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The availability of onshore and offshore three-dimensional seismic surveys facilitated detailed seismic sequence-stratigraphic interpretation of a large swath of the western Nile Delta evolution since the late Oligocene. The resulting sequence-stratigraphic framework is calibrated against more than 60 wells. The interpretation of repetitive sequence boundaries, that is, unconformities, on seismic sections was constrained by high-resolution abundance and diversity within biostratigraphic data sets and lithofaciesstacking patterns interpreted from well logs. Our series of depositional facies maps reflect environments of undifferentiated lowstand and transgressive systems tracts, that is, depositional elements interpreted between the lower bounding unconformity surface (sequence boundary) and maximum flooding surface above. These typically constitute terrestrial distributary channels and floodplains landward of strike-aligned lowstand deltas and marine shoreline deposits at and over the relict shelf break area of the underlying sequence boundary. Basinward deep-marine shales, slope channels, splays, fans, and terminal channel lobes define the remainder of the deposition over the rather extensive deep-marine slope apron region of the western Nile Delta. Incised valleys, canyons, and broad slope channels often confine any of the above-mentioned depositional facies at the lower bounding unconformity of each sequence. [ABSTRACT FROM AUTHOR]

Intestinal epithelial stem cells are highly sensitive to differentiation induced by endoplasmic reticulum (ER) stress. Colorectal cancer develops from mutated intestinal epithelial stem cells. The most frequent initiating mutation occurs in Apc, which results in hyperactivated Wnt signalling. This causes hyperproliferation and reduced sensitivity to chemotherapy, but whether these mutated stem cells are sensitive to ER stress induced differentiation remains unknown. Here we examined this by generating mice in which both Apcand ER stress repressor chaperone Grp78can be conditionally deleted from the intestinal epithelium. For molecular studies, we used intestinal organoids derived from these mice. Homozygous loss of Apcalone resulted in crypt elongation, activation of the Wnt signature and accumulation of intestinal epithelial stem cells, as expected. This phenotype was however completely rescued on activation of ER stress by additional deletion of Grp78. In these Apc-Grp78double mutant animals, stem cells were rapidly lost and repopulation occurred by non-mutant cells that had escaped recombination, suggesting that Apc-Grp78double mutant stem cells had lost self-renewal capacity. Although in Apc-Grp78double mutant mice the Wnt signature was lost, these intestines exhibited ubiquitous epithelial presence of nuclear β-catenin. This suggests that ER stress interferes with Wnt signalling downstream of nuclear β-catenin. In conclusion, our findings indicate that ER stress signalling results in loss of Apcmutated intestinal epithelial stem cells by interference with the Wnt signature. In contrast to many known inhibitors of Wnt signalling, ER stress acts downstream of β-catenin. Therefore, ER stress poses a promising target in colorectal cancers, which develop as a result of Wnt activating mutations.

Increased risk of allergy during early life indicates deficient immune regulation in this period of life. To date, the cause for inefficient neonatal immune regulation has never been elucidated. We aimed to define the ontogeny of oral tolerance and to identify necessary conditions specific for this stage of life. Ovalbumin (OVA) was administered orally to mice through breast milk and efficiency of systemic tolerance to OVA was assessed in adulthood using a model of allergic airway inflammation. Oral tolerance induction was fully efficient starting third week of life. Inefficiency in neonates was a consequence of abnormal antigen transfer across the gut barrier and retinaldehyde dehydrogenase expression by mesenteric lymph node CD103+neonatal dendritic cells, resulting in inefficient T-cell activation. Neonates’ serum retinol levels were three times lower than in adult mice, and vitamin A supplementation was sufficient to rescue neonatal defects and allow tolerance induction from birth. The establishment of oral tolerance required the differentiation of Th1 lymphocytes in both vitamin A-supplemented neonates and 3-week-old unsupplemented mice. This knowledge should guide the design of interventions for allergy prevention that are adapted to the neonatal stage of life such as vitamin A supplementation.

The human appendix has long been considered as a vestigial organ, an organ that has lost its function during evolution. In recent years, however, reports have emerged that link the appendix to numerous immunological functions in humans. Evidence has been presented for an important role of the appendix in maintaining intestinal health. This theory suggests that the appendix may be a reservoir or ‘safe house’ from which the commensal gut flora can rapidly be reestablished if it is eradicated from the colon. However, the appendix may also have a role in the development of inflammatory bowel disease (IBD). Several large epidemiological cohort studies have demonstrated the preventive effect of appendectomy on the development of ulcerative colitis, a finding that has been confirmed in murine colitis models. In addition, current studies are examining the possible therapeutic effect of an appendectomy to modulate disease course in patients with ulcerative colitis. This literature review assesses the current knowledge about the clinical and immunological aspects of the vermiform appendix in IBD and suggests that the idea of the appendix as a vestigial remnant should be discarded.

Concern with the environmental, economic, and social impacts of the post‐WWII model of agricultural intensification has led to renewed interest in grazing as a feeding strategy for temperate livestock farming systems. Putting grass back at the core of livestock feeding not only requires technical knowledge but also reconsideration of the importance of uncertainty in management choices. We developed a simple stochastic model of grassland dynamics to quantify both robustness and production of alternative management strategies under continuous grazing and management‐intensive rotational grazing. The model was calibrated on data from cool‐season grasslands in south‐central Wisconsin. We defined robustness as the probability that a given management strategy did not lead to overgrazing, while the production indicator was number of livestock unit days per hectare enabled by the grazing strategy. Robustness was strongly dependent on the timing and intensity of grazing, and the highest levels of production were incompatible with a high value of robustness. Beyond a certain threshold of production, we observed a trade‐off between robustness and production, where robustness decreased regularly until the maximum possible production. This trade‐off did not significantly differ between continuous grazing and rotational grazing. We identified key management practices that led to both high production and high robustness, but to attain these results will require not only acquisition of new technical knowledge but also a change in the way the system is managed: from controlling environmental variability with external inputs to understanding and managing stochastic systems in a way that reduces negative externalities while increasing production efficiencies.

Residual sward height (RSH) has a significant impact on temperate perennial grass growth, but its effect is rarely studied under grazing. We determined RSH effects on forage harvested (FH), seasonal yield distribution, nutritive value, and persistence of meadow fescue {Festuca pratensisHuds. subsp. pratensis[syn. Schedonorus pratensis(Huds.) P. Beauv.]}, orchardgrass (Dactylis glomerataL.), quackgrass [Elymus repens(L.) Gould], and reed canarygrass (Phalaris arundinaceaL.). Grasses were rotationally stocked with dairy heifers (Bos taurus) at vegetative stage (32‐cm height) to a 16‐, 8‐, or 2‐cm RSH or at mature stage (48‐cm height) to a 24‐, 12‐, or 4‐cm RSH in each of 2 yr. Grass FH and nutritive value were measured for each grazing event. Annual FH of grasses grazed at vegetative stage to a 2‐ or 8‐cm RSH was greater than that grazed to a 16‐cm RSH when precipitation was limiting, but few differences existed when precipitation was abundant. Annual FH of grasses grazed at mature stage increased as RSH decreased. As RSH increased, the mean grazing interval decreased, which increased the number of seasonal grazing events of vegetative but not of mature‐stage grasses. There was no apparent relationship between forage nutritive value and RSH. The primary risks incurred by grazing vegetative‐stage grasses to a shorter RSH (<8 cm) were reduced persistence in a dry year and delayed date of first grazing event the following spring. Little or no advantage in growth was gained by intentionally leaving a tall RSH when grazing mature‐stage grasses.

Meadow fescue [Schedonorus pratensis(Huds.) P. Beauv.] represents an alternative to temperate grasses typically used in forage‐livestock systems. Our objective was to compare the productivity, nutritive value, and persistence of diverse meadow fescue cultivars with that of tall fescue [Lolium arundinaceum(Schreb.) Darbysh.] and orchardgrass (Dactylis glomerataL.) when harvested by regimes representing lax and severe hay production and rotational grazing. ‘Azov’ (plant introduction strain cross), ‘Bartura’ (commercial cultivar), and ‘Hidden Valley’ (naturalized population) meadow fescue, ‘Barolex’ tall fescue, and ‘Bronc’ orchardgrass were harvested infrequently (40‐ to 65‐d harvest interval) or frequently (when plants reached 25‐cm sward height) to a 5‐ or 10‐cm residual sward height (RSH) at two Wisconsin locations in 2 yr. Annual dry matter (DM) yield of all grasses was greater when harvested infrequently (7.46 Mg ha−1) than frequently (5.92 Mg ha−1), or at 5 cm (7.52 Mg ha−1) than 10‐cm RSH (5.88 Mg ha−1). Tall fescue and orchardgrass annual yield was greater than that of all meadow fescues when harvested infrequently, but differences among grasses were relatively small when harvested frequently, particularly at 10‐cm RSH. Neutral detergent fiber digestibility (NDFD) of meadow fescue was 30 to 80 g kg−1neutral detergent fiber (NDF) greater than that of tall fescue or orchardgrass at every harvest in all environments. Meadow fescue cultivars were less persistent than tall fescue after 2 yr, but were usually equal to or more persistent than orchardgrass. Meadow fescue should be considered as a viable alternative to tall fescue and orchardgrass in temperate, managed intensive rotational grazing systems due to its comparable yield and superior digestibility.

Alfalfa (Medicago sativaL.) proteins ingested by dairy cows typically degrade at rapid rates and exhibit extensive ruminal degradability. Although the effects of conservation method (hay or silage) on these characteristics have been evaluated extensively, agronomic factors, such as harvest timing, have not. Our objective was to quantify rumen degradable protein (RDP) for ‘Affinity’ alfalfa harvested over a range of ages (0, 5, 10, 15, and 20 d following Stage 2) within each of four harvest periods (spring, early and late summer, and fall). For 2004, there were no interactions (P≥ 0.372) between harvest period and days within harvest period for any protein component. Crude protein (CP), neutral‐detergent soluble CP (NDSCP; g kg−1dry matter [DM]), and RDP (g kg−1DM) declined in a quadratic (P≤ 0.026) relationship with days following Stage 2. A quadratic (P= 0.002) pattern also was observed for rumen undegradable protein (RUP), but the overall range was small (60.4–66.5 g kg−1DM). On a CP basis, RDP declined linearly (P< 0.001) from 720 to 659 g kg−1CP during 2004. For 2005, there were interactions (P≤ 0.020) of harvest period and days within period for all protein‐related response variables, but trends over time within each harvest period generally were similar to those observed in 2004. Overall, RDP declined as alfalfa plants aged within harvest period, but these responses were due pri marily to reduced concentrations of CP within the cell‐soluble fraction.

Pasture management and broiler litter application rate are critical factors influencing the magnitude of nutrients being transported by runoff from fields. We investigated the impact of pasture management and broiler litter application rate on nutrient runoff from bermudagrass (Cynodon dactylon) pastures. The experiment was conducted on a Ruston fine sandy loam with a factorial arrangement on 21 large paddocks. Runoff water was collected from natural rainfall events from 2001 to 2003. Runoff water and soil samples were analyzed for nutrients and sediments. Runoff was generally greater (29%) from grazed than hayed pastures regardless of the litter application rate. There was greater inorganic N in the runoff from grazed paddocks when litter rate was based on N rather than P. The mean total P loss per runoff event for all treatments ranged from 7 to 45 g ha−1and the grazed treatment with litter applied on N basis had the greatest total P loss. Total dissolved P was the dominant P fraction in the runoff, ranging from 85% to 93% of the total P. The soluble reactive P was greater for treatments with litter applied on N basis regardless of pasture management. Runoff total sediments were greater for N‐based litter application compared to those which received litter on P basis. Our results indicate that litter may be applied on N basis if the pasture is hayed and the soil P is low. In contrast, litter rates should be based on a P‐basis if pasture is grazed.

Factors that contribute to high soil P in bermudagrass [Cynodon dactylonL. (Pers.)] pastures include continued use of broiler litter rich in P to meet forage N requirements and removal of hay in summer only. This study determined if harvesting annual ryegrass (Lolium multiflorumLam.) in addition to bermudagrass would reduce surplus soil P, Cu, and Zn faster than bermudagrass alone after litter application ceased on a Ruston soil (fine‐loamy, siliceaous, semiactive, thermic Typic Paleudults). During a 3‐yr build‐up, ‘Coastal’ bermudagrass was fertilized with 0, 4.5, 9, 18, and 36 Mg ha−1litter yr−1During the drawdown phase, plots were split and half was overseeded with ryegrass in fall 2001, 2002, and 2003. Whole plots were fertilized with NH4NO3in spring–summer to provide 268 kg ha−1N yr−1. Forage yield and P uptake increased as antecedent litter rate increased, and were greater in ryegrass–bermudagrass than bermudagrass in 2002, but not 2003. At 9 Mg ha−1litter, harvesting ryegrass in addition to bermudagrass increased P uptake by 10 to 55%, depending on study year. During the drawdown phase, soil Mehlich‐3 P (M3P) and water‐extractable P to 15‐cm depth decreased by as much as 50 and 70%, respectively. Soils analysis within each sampling date found no significant effect of forage system or its interaction with litter rate. Data for 9 Mg ha−1litter rate indicated 2 yr of forage P removal decreased residual M3P to an acceptable agronomic level (<70 mg kg−1). The potential to decrease surplus soil P by ryegrass–bermudagrass hay harvests was greatest when rainfall was inadequate for optimum bermudagrass yield.

Intake of animals grazing grass pasture is in part influenced by canopy density. Our objective was to determine the vertical distribution of dry matter and neutral detergent fiber (NDF) within temperate perennial grass swards. The study was conducted in 2004 and 2005 on a Plano silt loam (fine‐silty, mixed, superactive, mesic Typic Argiudolls). When leaf height of each grass reached 25 cm in spring, summer, and fall, canopy layers were harvested from 20 to 25, 15 to 20, and 10 to 15 cm. Differences in canopy density were usually not significant when precipitation was below normal. With abundant spring precipitation, quackgrass [Elymus repens(L.) Gould] had greater upper canopy density (1.9 mg dry matter [DM] cm−3) than any of the other grasses studied. Grasses typically grazed at shorter heights such as bluegrass (Poa pratensisL.) and perennial ryegrass (Lolium perenneL.) had greater density in the lower canopy layer (1.0–1.3 g DM kg−1). While soft‐leaf tall fescue (Festuca arundinaceaSchreb.), reed canarygrass (Phalaris arundinaceaL.), and meadow fescue (Festuca pratensisHuds.) had lower density in the upper canopy than timothy (Phleum pratenseL.) and quackgrass in the spring, the reverse was true in the summer. Herbage NDF of grasses generally increased from the upper to lower canopy layer (mean difference of 50 g kg−1); perennial ryegrass and meadow fescue often had the lowest NDF throughout the canopy (range of 392–452 and 418–469 g kg−1, respectively). Pasture intake may benefit from a diverse species composition because animals can graze a mixture having optimum density and NDF throughout the canopy.

In the southeastern USA, bermudagrass [Cynodon dactylon(L.) Pers.] is a principal species to which animal wastes are applied for nutrient removal. Diseases caused by Exserohilum, Bipolaris, and Curvulariaspp. may limit its effectiveness for this purpose. This study evaluated responses of seven forage bermudagrass cultivars (Alicia, Brazos, Coastal, Common, Russell, Tifton 44, and Tifton 85) to two pathogens, E. rostratum(Drechs.) Leonard & Suggs and B. spicifera(Bain) Subram., and persistence of cultivars with natural infection in the field. All cultivars were susceptible to both pathogens with foliar inoculations, but differed in degrees of susceptibility. Alicia was highly susceptible to both pathogens. Coastal was least susceptible to B. spicifera, but no cultivar was consistently least susceptible to E. rostratumPersistence of cultivars for up to 1 yr in the field differed and appeared related to both sod density and susceptibility to pathogens. Dense sods appeared to enable cultivars to generate more top growth and compensate for disease losses. Common, Coastal, and Tifton 44 bermudagrasses were most persistent in the field; Tifton 85 and Alicia were least persistent. Results indicate that resistance to dematiaceous hyphomycetous pathogens, along with a strong sod‐forming ability, is desirable in forage bermudagrass cultivars to sustain their persistence and productivity on animal waste application sites.

Land application of poultry litter provides essential nutrients for hybrid bermudagrass [Cynodon dactylon(L.) Pers.] production, but ammonia (NH3) volatilization and N mineralization influence the amount of litter N available for plant uptake. Our objective was to determine the combination of broiler litter and fertilizer N, which maximizes the yields of forage and N, P, and K by ‘Coastal’ bermudagrass. Studies were conducted for 3 yr (1999–2001) in pastures at Newton and Mize, MS that differed widely in soil test P (STP) due to history of litter application (0 vs. 30+ yr, respectively.). Litter rates of 0, 4.5, 8.9, 13.4, and 17.9 Mg ha−1were obtained by up to four monthly (April–July) applications of 4.5 Mg ha−1and were supplemented with ammonium nitrate (NH4–NO3) to provide the same total N in each treatment. At Newton, combining litter with fertilizer N increased forage yield by 10% in 1999, 25% in 2000, and 34% in 2001, as compared to fertilizer N. At Mize, K uptake increased as litter rate increased in 2001 only. These responses to litter were related to increased soil P and K at Newton, and increased soil N, P, and Ca at Mize. Averaged across years, maximum P uptake of about 40 kg ha−1was obtained by applying 8.9 Mg litter + 134 kg N ha−1at Newton and 4.5 Mg litter + 202 kg N ha−1at Mize. Safe and effective management of major plant nutrients in broiler litter may require the use of commercial N fertilizer.

Among forage crops utilized in the southeastern USA, bermudagrass [Cynodon dactylon(L.) Pers.] has the greatest potential to recover nutrients from soil routinely fertilized with broiler litter due to its yield potential and wide adaptation. Our objective was to determine differences in N and P uptake among diverse bermudagrass cultivars fertilized with broiler litter. ‘Alicia’, ‘Brazos’, ‘Coastal’, ‘Russell’, ‘Tifton 44’, and ‘Tifton 85’ hybrid bermudagrass and common bermudagrass were grown on a Savannah fine sandy loam (fine‐loamy, siliceous, semiactive, thermic Typic Fragiudult) and fertilized with 11.8 Mg litter dry matter (DM) ha−1yr−1(15.75 Mg as‐is basis) to provide 540 kg total N ha−1yr−1and 330 kg total P ha−1yr−1(mean of 4 yr). Alicia, Coastal, and Russell had similar annual yield in 3 of 4 yr, but yield differences among other hybrids were not consistent. Although annual N and P uptake of common bermudagrass was equivalent to Alicia, Coastal, and Tifton 44 during 2 yr due primarily to greater herbage N and P concentration, reduced uptake in years of below‐normal precipitation indicates it is not an acceptable alternative to a hybrid. No differences in N uptake existed among a majority of hybrids when precipitation was near normal, and Alicia, Coastal, and Russell had equivalent N uptake all 4 yr. Nitrogen and P uptake of Tifton 85 increased each year and, by the final year of the study, exceeded that of all cultivars. Among all the hybrids, only Russell exhibited consistent superior P uptake relative to Coastal.

Understanding manure nutrient dynamics in soil with any crop is an important management practice for farmers and producers to document accountability and to use manure resources optimally. A field experiment was conducted to quantify input, output, and the year‐round major plant nutrient dynamics in a fine sandy loam soil supplied with 15.75 Mg ha−1yr−1broiler litter. Soil samples were collected from pre‐established plots of common bermudagrass [Cynodon dactylon(L.) Pers.] and hybrid bermudagrass cultivars Coastal and Tifton 85 for nutrient analysis. Coastal and Tifton 85 produced significantly greater annual dry matter yield (16948 and 18772 kg ha−1) than common bermudagrass (11238 kg ha−1). Tifton 85 was most efficient and removed 344, 58, and 472 kg ha−1N, P, and K, respectively. The removal efficiency of these nutrients for Tifton 85 was 73, 18, and 114%, respectively. Soil pH varied from 6.0 to 6.6 until it decreased unexpectedly to 5.6 by the end of 2001. Total soil C increased from 11.4 g kg−1to 17.9 g kg−1by the end of the second year. At all sampling dates, the NO3–N concentration was greater than NH4–N while total N decreased during the maximum uptake in late spring and summer. Both total P and Mehlich‐3 extractable P concentrations increased mainly in the 5‐ to 10‐cm depth, indicating slight leaching of P. Results indicated that top yield from hybrid bermudagrass cultivars is possible with broiler litter as a sole fertilizer source. However, considerable nutrient imbalances in soil may occur in the long term if improper litter rates are used.

Bermudagrass [Cynodon dactylon(L.) Pers.] has great potential to recover nutrients due to its pronounced yield response to N. Our objective was to determine differences in forage dry matter (DM) yield, nutrient concentration, and nutrient uptake among diverse bermudagrass cultivars fertilized with swine effluent. ‘Alicia’, ‘Brazos’, ‘Coastal’, ‘Russell’, ‘Tifton 44’, and ‘Tifton 85’ hybrid bermudagrass and common bermudagrass were grown on a Brooksville silty clay loam (fine, smectitic, thermic Aquic Hapludert) and fertilized with effluent to provide 370 and 61 kg ha−1yr−1N and P, respectively (mean of 3 yr), and on an Atwood silt loam (fine‐silty, mixed, thermic Typic Paleudalf) and fertilized to provide 200 and 38 kg ha−1yr−1N and P, respectively. Annual DM yields of Brazos, Coastal, Russell, and Tifton 85 were similar on Brooksville (23.3–24.2 Mg ha−1) and Atwood (12.3–14.1 Mg ha−1) soils. Annual N and P uptake ranged from 422 to 467 kg N ha−1and 50 to 58 kg P ha−1on the Brooksville soil and from 181 to 230 kg N ha−1and 32 to 40 kg P ha−1on the Atwood soil. Common bermudagrass uptake of N and P was similar to or greater than all hybrids except Russell on Atwood soil due to greater herbage N and P concentration. Hybrids generally recovered more K, Cu, and Zn than common bermudagrass. Relatively small differences in nutrient uptake among the bermudagrass cultivars suggest that forage quality, winter hardiness, and establishment cost be given equal consideration when choosing a cultivar.

Three methods are described, in the context of the guiding principles of green chemistry, for the catalytic oxidation of alcohols. The first employs a recyclable oligomeric TEMPO catalyst (PIPO) and sodium hypochlorite as the oxidant in a bromide-free and chlorinated hydrocarbon solvent-free system. The second involves a ruthenium/TEMPO catalyst and oxygen as the oxidant. The third consists of a recyclable water-soluble palladium−diamine complex in conjunction with air as the oxidant in an aqueous biphasic system. The mechanisms of the ruthenium/TEMPO- and palladium-catalyzed oxidations are discussed, and the mechanism of the former is compared with that of the analogous copper/TEMPO catalyst.

Small‐type white clover, Trifolium repensL., plants predominate in most closely grazed pastures in the southeastern USA. The role of relative seed production in stand persistence of white clover types in pastures has not been quantified. This study compared the relative seed production of seven small‐type naturalized populations with that of seven large‐type white clover cultivars and germplasms in a pasture. All entries were space‐planted into plots in a common bermudagrass [Cynodon dactylon(L.) Pers.] pasture at Mississippi State, MS, on a Savannah fine sandy loam (fine‐loamy, siliceous, semiactive, thermic Typic Fragiudult) in fall 1995 and 1996, and grazed with cattle prior to flowering and seed production. All naturalized populations averaged about three times as many flowers and seed‐bearing flowers as all cultivars other than ‘Louisiana S‐1’ each year. Flower production differences were consistent throughout the study, though maximum flower production for naturalized populations was earlier in the season than cultivars. Seed production differences were similar to flower production, as cultivars averaged only 27 to 43% as much seed as naturalized populations. The low growth stature and excessive seed production of naturalized populations enable them to tolerate close continuous grazing and have a greater opportunity to reseed in pastures than common large‐type cultivars. This reseeding potential probably contributes to the domination of small‐type white clover in closely grazed pastures of the southeastern USA.

BACKGROUND: The bacterium Helicobacter pylori is able to adhere to and to colonise the human gastric epithelium, yet the primary gene product responsible as a receptor for its adherence has not been identified. AIMS: To investigate the expression of the gastric mucins MUC5AC and MUC6 in the gastric epithelium in relation to H pylori colonisation in order to examine their possible roles in the binding of H pylori. PATIENTS: Seventy two consecutive patients suspected of having H pylori infection. METHODS: MUC5AC, MUC6, and H pylori were detected in single sections of antral biopsy specimens using immunohistochemical triple staining. RESULTS: MUC5AC was expressed in the superficial epithelium and the upper part of the gastric pits. MUC6 expression was detected in the lower part of the gastric pits. The expression of both mucins in the epithelium was complementary. In each patient, there was a sharply delineated transition between MUC5AC and MUC6 producing cell populations. In all H pylori positive patients there was a striking colocalization of H pylori and MUC5AC; more than 99% of the bacteria were associated with either extracellular MUC5AC or the apical domain of MUC5AC producing cells. CONCLUSIONS: H pylori is very closely associated with extracellular MUC5AC and epithelial cells that produce MUC5AC. This indicates that MUC5AC, but not MUC6, plays a role in the adhesion of H pylori to the gastric mucosa.

Naturalized populations, or ecotypes, of white clover (Trifolium repensL.) are found in many southeastern U.S. pastures, often persisting despite adverse environmental and cultural conditions. Our objective was to compare the growth, morphology, and vegetative persistence of white clover ecotypes (small‐ to medium‐leaf) with selected cultivars (large‐leaf) and improved germplasm under grazing in four southeastern states. Seed or stolons of white clover ecotypes were collected primarily from grazed pastures in spring 1994 in Louisiana, Mississippi, Alabama, and Georgia, and increased by intercrossing. Plots of seven ecotype collections, ‘Osceola’, ‘Regal’, ‘Louisiana S‐1’, ‘Grasslands Huia’, ‘Grasslands Prestige’, Brown Loam Synthetic No. 2 germplasm, and Southern Regional Virus Resistant germplasm were established in October 1995 in each state. Plots were stocked continuously with cattle (Bos taurus) (5‐cm stubble) from January 1996 to January 1998. Stolon length and axillary bud viability, and number of stolon apices, rooted nodes, and seedlings were measured every 3 mo. Stolon length of the ecotypes usually exceeded that of the cultivars and germplasm at all locations, particularly in the winter and spring. By the end of the experiment, the ecotypes also exhibited greater stolon branching than the cultivars and germplasm (1580 vs. 320 branches m−2). Superior vegetative growth of the ecotypes was attributed to a greater proportion of the stolon nodes being both branched and rooted, particularly during the summer. White clover ecotypes represent a valuable source of germplasm to incorporate into breeding programs or to develop directly into more persistent cultivars.

The use of plant material outside the country of development is common, but whether such material is superior to existing types of the same species is questionable. Seven United States and eight New Zealand white clover (Trifolium repens) cultivars, germplasms, or breeding populations were evaluated for plant spread and dry matter yield for two years at Mississippi State, Mississippi, USA, when grown in monoculture or with grasses having differing seasonal growth patterns, viz tall fescue (Festuca arundinacea) and bermudagrass (Cynodon dactylori). Plant material originating in the United States had 49-53% greater plant spread and 79-222% greater clover dry matter yield in monoculture or in association with either grass than the New Zealand material. Osceola, SRVR, and Brown Loam Syn#2 white clover had greater plant spread than all New Zealand material at 9 of 11 sampling dates. White clover spread and yield under monoculture showed a closer correlation with growth in association with common bermudagrass than with tall fescue. White clover should be selected in the climate and with the grass association in which it is to be utilised.

The southern root‐knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood] reduces the productivity and persistence of white clover (Trifolium repensL.) throughout the southeastern USA. Our objective was to determine the response of two white clovers with differing M. incognitatolerance to nematode infection across a range of plant densities. Nematode‐susceptible ‘Regal’ and tolerant germplasm SC‐1 were established in the greenhouse at 3, 6, 12, 24, and 48 plants per fiat (0.I m−2) and root‐knot n ematode ( Race 4) eggs were applied to each fiat at 0 (control), 600 (low), or 1200 (high) eggs per 500 cm3of soil mix. Regal exhibited no tolerance to infection, while SC‐1 exhibited tolerance (equivalent dry matter [DM] yield across initial nematode egg levels) in the first repetition of the experiment only. Total DM yield of Regal and SC‐1 increased quadratically with increasing plant density across initial nematode egg levels in the first repetition, indicating DM yield suppression was caused by factors related to intraspecific competition, rather than by nematode infection. In the second repetition, DM yield of both clovers increased linearly with increasing plant density at the low and high initial egg levels, indicating that nematode infection had a greater effect on yield than intraspecific competition. Nematode reproduction was not influenced by plant density. Stolon dry weight of both clovers was reduced a mean of 60% by nematode infection. Because total DM yield of nematode‐infected white clover increased with increasing plant density due to greater early harvest productivity immediately following nematode inoculation, increasing plant density would not be an effective means of increasing long‐term forage productivity.

Annual legumes are potential N sources in forage‐livestock systems, but information on the quantity and distribution of N2fixed is lacking. Field experiments were conducted to determine the quantity and seasonal distribution of N2fixed by two annual clovers, ‘Tibbee’ crimson clover (Trifolium incarnatumL.) and ‘Mt. Barker’ subterranean clover (T. subterraneumL.), having diverse annual dry matter (DM) production patterns. Plots were established on a Catalpa silty clay soil (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) in each of 2 yr. Dinitrogen fixation was estimated by the I5N isotope dilution method with ‘Marshall’ annual ryegrass [Lolium multiflorum(L.) Lam.] as the non‐N2‐fixing control. A mean of 77% of the annual herbage yield provided by crimson clover was obtained by early April compared to 39% for subterranean clover. Subterranean clover produced greater annual herbage yield than crimson clover the first year (7.6 vs. 6.4 Mg DM ha−1), while yields under drought conditions were similar the second year (mean of 4.8 Mg DM ha−1). The clovers fixed an average of 196 and 114 kg N ha−1in the first and second years, respectively. Depending on the harvest date, fixed N2comprised 32 to 91% of total N in crimson clover and 75 to 91% of total N in subterranean clover. The average seasonal proportion of N derived from symbiosis by both clovers was equivalent in the first and second year (mean of 81 and 75%, respectively). Seasonal need for herbage production, rather than N2fixation capability, may govern the value of crimson vs. subterranean clover in forage‐livestock systems.

Periods of drought, common during the summer and fall in the southeastern USA, can be detrimental to growth of the shallowrooted, temperate forage legume, white clover (Trifolium repensL.). Our objective was to determine the growth response (lateral spread, morphology) of white clover to a water‐application gradient during the summer and fall on a Marietta fine sandy loam (fine‐loamy, siliceous, thermic Fluvaquentic Eutrochrept). From May to October, a linesource irrigation system produced regimes of high, medium, low, and zero water‐application across parallel 1.0‐m rows of three cultivars and three germplasms transplanted (10 plants row−1) into a common bermudagrass (Cynodon dactylon(L.) Pers, var. dactylon) sod the previous fall. Plots were continuously‐stocked (5‐cm stubble) with cattle (Bos taurusL.). Each month, differences in lateral plant spread among entries were similar regardless of water‐application regime. Within each regime, spread declined sharply after June and remained near a minimum (<0.20 m2row−1) from August until October. Yield and morphology differences among entries in July were similar in each of the water‐application regimes as well. By October, however, there were differences in herbage yield, stolon length, and number of stolon apices among entries at the high water‐application regime, but not at the medium, low, and zero regimes. The results suggest that either there is no difference in drought tolerance among these cultivars and germplasms, or that white clover drought tolerance does not impact growth in the presence of stresses such as grazing and associated grasses.

This study was conducted to determine the rate of enzymatic hydrolysis of isolated cellulose from grass and legume forages important to the southeastern USA, and to compare the difference in hydrolysis rate between grasses and legumes at two stages of maturity. Cellulose from six grass and nine legume species harvested at two stages of maturity were isolated using an acid chlorite delignification procedure followed by hemicellulose extraction with 0.12 MNaOH solution. Residual dry matter from isolated cellulose samples was determined to contain between 901 and 958 g kg−glucose. Cellulose samples were incubated at 40°C in a solution of commercially obtained cellulose enzyme for 8 h. Solutions were sampled at hourly intervals and analyzed for glucose concentration. Results indicated that glucose production was linear during the sampling period for all cellulose samples. The rate of enzymatic hydrolysis was greater (P< 0.01) for cellulose isolated from grass samples than from legume samples (8.06 and 6.94 mg kg 1s 1, respectively). Stage of maturity also affected enzymatic digestion rate (P< 0.01). Rates for enzymatic digestion of cellulose from immature and mature forage were 8.61 and 8.06 mg kg 1s 1, respectively. Even though enzymatic digestion rates between grasses and legumes were significantly different, the differences were small. Correlation between cellulose digestion rate and in vitro dry matter digestion of forage was not significant, indicating that cellulose digestion rate was not important in determining digestibility of whole plant tissue.

Winter annual legumes seeded in perennial clover‐tall fescue pastures could increase early spring herbage production without N fertilizer. This study determined the productivity and forage quality of ‘Regal’ white (Trifolium repensL.) and ‘Kenland’ red clover (T. pratenseL.)/tall fescue (Festuca arundinaceaSchreb.) mixtures grown with and without ‘Yuchi’ arrowleaf (T. vesiculosumSavi.), ‘Tibbee’ crimson (T. incarnatumL.), and ‘Meteora’ subterranean clover (T. subterraneumL. var. yanninicum[Katzn. & Morley] Zoh.). The experimental design was a split plot with four replicates. Whole plots were red, white, red + white, and no perennial clover. Subplots were arrowleaf, crimson, subterranean, and no annual clover. All species were broadcast seeded on a Catalpa silty clay (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) at Mississippi State, MS, in October 1984. The annual clovers were reseeded in September 1985 and 1986. Arrowleaf and crimson clover competition resulted in 11% less total dry matter and 16% less clover yield compared to no annual clover in perennial clover plots during the first 2 yr of the study. The only yield advantage for perennial clover/tall fescue mixtures with arrowleaf or crimson clovers was in the third year when perennial clover stands declined (mainly due to dry weather conditions) and annual clover overseeding gave 114% greater clover yields. Subterranean clover had little effect on yield or forage quality when grown with perennial clovers. Crude protein and in vitro digestible dry matter concentrations were increased in early spring 1985 and 1987 by the addition of arrrowleaf or crimson clovers to perennial clover plots.

We have measured the radiative lifetime of the (5d6p)3D3state of barium by Hanle effect. This state was populated by cw dye laser excitation of an atomic beam of Ba in the metastable (5d6s)3D3state. The metastable state was populated by a dc discharge. With dye laser excitation, the shape of the Hanle effect curve is strongly modified due to optical pumping of the metastable state. A brief discussion of the expected and observed signal shapes is given. The radiative lifetime of the (5d6p)3D3state is measured to be τ= 10.2 ± 1.5 ns.

Forage digestibility is influenced by plant cell wall composition. We compared changes in cell wall composition of the herbage and plant fractions of four clovers differing in life cycle and growth habit and examined the relationship between digestibility and cell wall composition in these plant fractions. Primary spring growth of berseem (Trifolium alexandrinumL.), red (T. pratenseL.), subterranean (T. subterraneumL.), and white (T. repensL.) clover was harvested in each of 2 yr beginning in late March and thereafter every 10 d (eight harvests total). Cell wall, hemicellulose, cellulose, and lignin concentration were determined for leaf, petiole, stem, and reproductive fractions and herbage at each harvest. Herbage cell wall concentration of berseem, red, and white clover increased 3.1, 2.4, and 0.8 g kg−1d−1, respectively. Maximum herbage cell wall concentrations of annual berseem and subterranean clover herbage were greater than those of perennial red and white clover(500 and 497 vs. 425 and 280g kg−1respectively). With the exception of subterranean clover, leaf cell wall concentration of all clovers ranged from ≈ 200 to 300g kg−1Trends for stem cell wall and hemicellulose Concentration of erect‐growing berseem and red clover were similar, while petiole cell wall and hemicellulose trends were similar for annual berseem and subterranean clover. Herbage and plant fraction cell wall concentration were negatively correlated with digestibility due primarily to the inverse relationship between digestibility and cell wall‐ligning cncentration. The minor differences in leaf cell wall concentration during primary spring growth indicate minimal differences exist among these clovers in relation to their value to grazing ruminants.

Climatic conditions contribute to reduced white clover (Trifolium repensL.) productivity and plant survival in the southeastern USA, particularly during the summer. Our objective was to determine the influence of cutting height and frequency on yield and plant morphological traits associated with survival of white clover under humid‐subtropic conditions. Regal (large‐leaf), Louisiana S‐1 (medium‐largeleaf),and Grasslands Huia (medium‐small‐leaf) white clover were sown on a Catalpa silty clay (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) and were cut every 7, 28, and 49 d at a 2.5‐ and 10‐cm stubble height from March to November. Forage yield was measured at each harvest. Stolon growth and branching (growing point density; GPD) and post‐harvest leaf area index (LAD were measured in May, August, and November. Dry matter (DM) yield measured by season (spring, summer, and autumn) increased as leaf size increased and cutting height decreased. The effect of cutting height on stolon DM was opposite that of its effect on DM yield. After the spring, stolon DM of all cultivars was reduced by harvesting at 2.5‐ vs. 10.0‐cm stubble, regardless of cutting interval. Within a cutting height, increasing the harvest interval from 7 or 28 to 49 d generally resulted in greater stolon DM accumulation by autumn. During much of the growing season, there was a positive association between stolon GPD and post‐harvest LAI. Our results suggest that close defoliation of white clover (2.5‐cm stubble) during the summer and autumn detrimental to plant survival, particularly when combined with a short (7‐d) defoliation interval.

Yield response of white clover (Trifolium repensL.) to defoliation varies with leaf size. Our objective was to determine how specific aspects of plant morphology and physiology are responsible for differences in growth of diverse white clover cultivars in response to defoliation interval. Individual plants of ‘Aberystwyth S184’ (small‐leaf), ‘Grasslands Huia’ (medium‐smali‐leaf), and ‘Osceola’ (large‐leaf) were clipped to remove all fully expanded leaves and petioles 55 d after sowing in the greenhouse and then clipped every 7, 14, or 28 d for the next 28 d. Plant fraction dry matter (DM) accumulation and morphological and physiological characteristics were measured 1, 3, 7, 14, and 28 d after the final clipping. Stolon growth rate was inverse to leaf size classification (Aberystwyth S184, 7.6 cm d−1Grasslands Huia, 5.8 cm d−1> Osceola, 3.6 cm d−1). In contrast, maximum stolon weight/length ratio of Osceola increased 31% vs. a 1% increase for Grasslands Hula and Aberystwyth S184 as defoliation interval increased to 28 d, which resulted in greater stolon DM accumulation by Osceola at the 14‐ and 28‐d intervals. Stolon and root carbohydrate concentration of Osceola was greater than and leaf carbohydrate concentration was less than the other cultivars at all defoliation intervals, indicating greater reliance on stored carbohydrates for regrowth by Osceola. Although plant leaf area of Oseeola was greater than that of Grasslands Hula and Aberystwyth S184 at the 28‐d interval only, forage DM accumulation of Osceola was greatest at all intervals due to petiole length. In grazed swards, however, greater petiole length would likely increase accessibility to and removal of leaf tissue, subsequently reducing new leaf and stolon growth.

Recent evidence has indicated the superior quality of barley (Hordeum vulgareL.) forage compared to that of oats (Arena salivaL.). Evaluations of alfalfa (Medicago salivaL.) persistence following the seeding year are needed to determine the potential of barley vs. oats as a companion crop during alfalfa establishment. Our primary objective was to determine the influence of establishment with barley or oat companion crops harvested at four small grain crop maturation stages on alfalfa persistence overwinter and first crop yield the following spring. Four cultivars each of barley and oats were established with alfalfa at each of two locations during each of 2 yr and harvested initially at each of four small grain crop maturation stages. Alfalfa was also established alone (solo‐seeded) with and without herbicides and was harvested at first flower. Alfalfa persistence (proportion of complete ground cover) and subsequent yield of all treatments were determined in the spring following the seeding year. Alfalfa persistence and subsequent spring yield were usually not affected by harvest stage or small grain crop cultivar when the companion crop was harvested initially at the five leaf, flag leaf, or dough stages, even though barley cultivars frequently had greater potential for competition with the alfalfa at each stage than oat cultivars as measured by ground photography, leaf area index, and seedling alfalfa yield. Barley cultivars also lodged more frequently than oat cultivars. When the first establishment year harvest of the companion crops occurred at grain stage, alfalfa stands were often reduced more than when harvest occurred at immature stages. Persistence of alfalfa established when ‘Morex’ barley or ‘Lyon’ oats and harvested initially at flag leaf stage and then at first alfalfa flower was not different from that of solo‐seeded alfalfa established with or without herbicides and harvested twice at first flower. However, under the same management (but with a greater interval between seeding year harvests), the subsequent spring yield of solo‐seeded alfalfa was greater than that of alfalfa sown with Morex barley or Lyon oats in one year at both locations. We conclude that the barley cultivars tested in this study were as successfully utilized as oat cultivars during alfalfa establishment when the companion crop was harvested at immature stages. Although risk of alfalfa stand loss was greater following harvest of the companion crops at grain stage, the influence of barley and oat cultivars on alfalfa persistence at this stage was inconclusive and varied with the location and year.

Oats (Avena sativaL.) is often chosen as a companion crop during the establishment of alfalfa (Medicago sativaL.). Recent research has shown barley (Hordeum vulgareL.) forage to have superior nutrient duality compared to that of oats. Our primary objective was to determine the forage quality and yield potential of representative barley and oat cultivars harvested at various maturity stages as companion crops during alfalfa establishment. Four cultivars each of barley and oats were established with alfalfa at each of two locations during each of 2 yr and harvested initially as forage at each of three small grain crop maturation stages. Alfalfa was also established alone (solo‐seeded) with and without herbicides, and was harvested at first flower. In vitro digestible dry matter (IVDDM) concentration of small grain‐alfalfa mixtures declined from 83 to 55 dag kg−1(%) dry wt as companion crop maturation increased from five leaf to dough stage, whereas crude protein (CP) concentration declined from 29 to 9 dag kg−1dry wt. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations increased with maturation until flag leaf stage, and then stabilized through dough stage. Average IVDDM concentration of mixtures of alfalfa and ‘Morex’ barley or ‘Lyon’ oats harvested initially at flag leaf stage was equivalent to or greater than that of solo‐seeded alfalfa established with or without herbicides. However, the average NDF and ADF concentrations of solo‐seeded alfalfa were lower than those of small grain‐alfalfa mixtures. Nutritive value and nutrient yield did not differ between soloseeded alfalfa established with and without herbicides. When barley and oat cultivars were used as companion crops for spring‐seeded alfalfa, barley mixtures harvested initially at the five leaf, flag leaf, or dough stage usually provided superior quality forage in the seeding year than did oat mixtures. However, annual IVDDM and CP yields were more influenced by location and year than by small grain species or cultivar.

The need for tall fescue (Festuca arundinaceaSchreb.) pasture renovation due to a fungal endophyte (Acremonium coenophialumMorgan‐Jones and Gams) that causes fescue toxicosis in grazing cattle (Bos taurusL.) has given farmers the opportunity to add white clover (Trifolium repensL.) to their improved pastures. This study was conducted to determine the compatibility of five white clover and five tall fescue cultivars grown in association during two seeding years and to determine any interactions between cultivars. ‘Regal’, ‘Tillman’, ‘Louisiana S‐1’, ‘Osceola’, and MS Brown Loam Syn. #6 white clover were grown in all combinations with ‘Kentucky 31’, ‘Kenhy’, ‘Johnstone’, ‘Triumph’, and ‘Missouri 96’ tall fescue in two separate seeding year studies. The studies were grown on a Catalpa silty clay (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) at Mississippi State, MS. Louisiana S‐1 associations produced significantly less total dry matter (DM) and white clover (WC) yield and more tall fescue (TF) yield than those of the other white clover cultivars across tall fescue cultivars. Triumph associations produced significantly less WC yield and more TF yield than those of the other tall fescue cultivars across white clover cultivars. No differences in total DM yield were observed for the tall fescue cultivars. No interactions between tall fescue and white clover cultivars were found in either seeding year. The cultivar relationships were constant over years an over harvests within years, though the botanical composition of the plots varied between harvests and years. Triumph was more competitive with white clover than the other tall fescue cultivars, and Louisiana S‐1 was less competitive with tall fescue than the other white clover cultivars during the seeding year. No advantage was found for any specific combination of white clover and tall fescue cultivars during the seeding year.

White clover (Trifolium repensL.) is commonly grown in a legume and grass mixture, but most selection for elite clones has been as spaced plants in monoculture. This study estimates (i) population parameters important to breeding white clover when grown with two different grasses or in monoculture, and (ii) the potential for improving yield of clover grown in grasses when selection is made in monoculture. Ramets of 47 randomly selected clones from Southern Regional Virus Resistant white clover germplasm were space‐planted and grown for 3 yr in three environments: in monoculture, in Tifton 44 hybrid bermudagrass (Cynodon dactylon(L.) Pens.), and in common bermudagrass. Plant spread, yield, and stolon branching were measured at four harvests. Compared with monoculture, competition with common and hybrid bermudagrass reduced clover yield 60 and 45%, respectively. Environment had variable effect on magnitude of heritability estimates, which were statistically significant for each trait in each environment (H= 58 to 72%) except yield in common bermudagrass. Genetic correlations between environments were significant for clover yield and plant spread. Predicted response to selection in grass was 12 to 31% more effective than selection in monoculture for yield and 71 to 90% more effective for plant spread. The selection for yield in hybrid bermudagrass to improve yield in common bermudagrass was predicted 30% more effective than direct selection. Selection in monoculture should improve performance with grasses, but clover yield will not be maximized until selection is completed in a grass environment.

Spaced‐plant arrangements provide a means of evaluating white clover (Trifolium repensL.) germplasm for a range of characteristics. Growth of spaced white clover plants in monoculture, however, may not be related to growth with grasses. Our objective was to determine the relationships among various growth parameters of white clover grown as spaced plants in monoculture and with contrasting grass swards. Vegetative clones of 47 plants of Southern Regional Virus Resistant white clover germplasm were planted on 1‐m centers in previously established common or hybrid (‘Tifton 44’) bermudagrass (Cynodon dactylon(L). Pers.) swards, in monoculture in a Catalpa silty clay soil (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) in the fall of 1988. Growth of each clone was measured in the spring and fall of 1989, and in the spring of 1990 and 1991. At each sampling, clover dry matter (DM) yield, plant spread, and stolon branching were lower for clones grown with common bermudagrass than with hybrid bermudagrass or in monoculture. Growth of clones with hybrid bermudagrass was intermediate to growth with common bermudagrass and in monoculture, presumably because of the density of aboveground competition from hybrid compared to common bermudagrass (260 vs. 470 g DM m−l2; 5‐cm stubble). Correlations between clover yield and stolon branching, and clover yield and plant spread were greatest for clones grown with common bermudagrass (0.42 and 0.85, respectively). Stolon branching of clones in monoculture was not correlated with stolon branching in either bermudagrass. The influence of the grass on stolon branching and the relationship of branching to persistence suggest the necessity of evaluating white dover germplasm in association with grasses.

The relative effects and consequences of split doses of exogenous insulin therapy (two thirds before breakfast and one third before the evening meal) on excursions and diurnal rhythm of circulating glucose during the 24-hour “metabolic clock” were examined. A longitudinal study in pregnant women with maturity-onset diabetes (N = 7) with substantial endogenous insulin secretion and juvenile onset diabetes (N = 6) with no measurable endogenous insulin secretion (judged by C-peptide measurement) was compared with identical studies performed in nondiabetic pregnant control subjects (N = 6). Plasma glucose levels determined at hourly intervals throughout the 24-hour meal-activity-sleep cycles revealed marked excursions of plasma glucose values with exaggerated hyperglycemia during the day hours and relative hypoglycemia at night in both types of diabetic pregnancies as compared to normal control pregnancies. The magnitude of glucose excursion was surprisingly large relative to the degree of increase in the mean 24-hour glucose levels and mean fasting blood glucose values. A striking disparity in the amount of exogenous insulin required to maintain glucose levels and diurnal rhythm toward the normal range in pregnant diabetic patients from second to the third trimester was observed. The degree of exogenous insulin increment imposed by pregnancy (from the second to third trimester) in juvenile-onset diabetes was relatively small (38%) and comparable to the increase in endogenous insulin (32%) found in nondiabetic pregnancies. In marked contrast, among patients with maturity-onset diabetes, in whom substantial endogenous insulin secretion was present, the corresponding increment in exogenous insulin was surprisingly large (98%) without a proportional reduction in 24-hour integrated glucose values. These findings indicate that the effects and consequences of exogenous insulin therapy between maturity-onset diabetes and juvenile-onset diabetes during pregnancy are clearly different. Our data further suggest that peripheral insulin resistance constitutes the major factor accounting for the persistence of hyperglycemia in maturity-onset diabetes. Although the mechanism by which the exaggeration of insulin resistance in maturity-onset diabetes with superimposed pregnancy remains unclear, there are at least three additive contributing events to consider: the inherent defect of insulin resistance in this type of diabetes, the pregnancy-induced insulin resistance, and the reduction in number or affinity of insulin receptors in target tissues occasioned by excessive exogenous insulin treatment.

A longitudinal study to quantitate the progressive effects of the second and third trimesters of normal pregnancy on the levels of plasma glucose, immunoreactive insulin (IRI), and C-peptide (C-P) at hourly intervals throughout the 24-hour “metabolic clock” was made. Identical studies were conducted in each subject at 6 to 11 weeks post partum and these data were used as nonpregnant control values. Data analyses were made to determine the role of meal-activity-sleep cycles as physiologic modifiers. A diurnal rhythm of plasma glucose, IRI, and C-P was demonstrated in all study periods. During meals anabolic values of plasma glucose (increments above the 24-hour mean) in response to meal intake were remarkably small, ranging between 30 and 35 mg/100 ml in the postpartum state, and were not significantly modified by pregnancy. The corresponding IRI levels were similarly small with a mean increase on only 31% in pregnancy. However, during the third but not the second trimester of pregnancy, the peak anabolic values for both plasma glucose and IRI were significantly (p < 0.05) increased and consequently the 2-hour postprandial glucose and IRI levels were significantly elevated after meal ingestion. When values were compared with those of the postpartum state, there was a progressive increase in the degree of catabolic excursion (decrease from 24-hour mean) of plasma glucose during sleeping hours from the second to third trimester of pregnancy. This resulted in a state of relative hypoglycemia, with significantly reduced fasting (8 a.m.) plasma glucose and 24-hour integrated glucose levels. This relative nocturnal hypoglycemia was associated with synchronous IRI values but without concomitant reduction of absolute IRI levels. Consequently, the fasting, premeal, and 24-hour IRI/glucose ratios were increased. Thus, basal insulin secretion is significantly augmented relative to levels of plasma glucose, but a quantitative increase in insulin secretion following food intake is relatively small during pregnancy. These observations together with the finding of a marked diurnal rhythm of plasma glucose and relative nocturnal hypoglycemia provide important insights for the formulation of guidelines for the timing, amount, and mode of delivery of exogenous insulin necessary for the management of diabetic patients during pregnancy.

The effect of pregnancy on the circadian rhythm and diurnal excursion of plasma cortisol and urinary free corticoids was examined in a sequential study during the second and third trimester and 6 to 12 weeks post partum. Hourly blood samples from six subjects and 8-hour urine collections from eight subjects were obtained around the clock. While the circadian rhythm was maintained during gestation, plasma cortisol levels (24-hour mean, nadir, peak, and nadir-peak excursion) increased. The relative excursion of plasma cortisol (expressed as the percentage of deviation from the 24-hour mean) exhibited remarkable blunting compared with postpartum values. This pregnancy-associated blunting of plasma cortisol excursion was indicated by a significant reduction in the: (1) mean peak and nadir excursion, (2) integrated area between the percent deviation curve and the 24-hour mean, and (3) mean slope of the major incremental and decremental segments of the percent deviation curve. The circadian rhythm and diurnal excursion of plasma cortisol were reflected in urinary free corticoid values. Mean 24-hour urinary free corticoid concentrations increased 180% during gestation over nonpregnant levels. Nadir concentrations of urinary free corticoids in pregnancy exceeded peak nonpregnant levels. The gestational rise of metabolically active free cortisol and adrenocorticotropin (ACTH), and the pregnancy-associated blunting of the excursion of plasma cortisol may be explained by an autonomous source of ACTH during gestation.

Grazing management is a major factor influencing white clover (Trifolium repensL.) growth. Our objective was to determine the response of white clover cultivars differing in leaf size to grazing method (continuous vs. rotational stocking) using cattle (Bosspp.). In each of 2 yr, a predominantly tall fescue (Festuca arundinaceaSchreb.) sod on a Savannah fine sandy loam (fine‐loamy siliceous, thermic Typic Fragiudult) was oversown in September with ‘Grasslands Huia’ (medium‐small leaf), ‘Louisiana S‐1’ (medium‐large leaf), and ‘Regal’ (large leaf) white clover. From March to August of the following year, plots of each cultivar were stocked continuously (3‐ to 5‐cm stubble) on rotationally (grazed to 5‐cm stubble every 35 to 38 d). Clover growth was measured prior to rotational grazing and stolon survival was determined in November. When precipitation during the grazing season was 59% above normal, grazing method had no influence on mean single leaf area, stolon dry weight, and stolon growing point density of white clover. In contrast, continuous stocking reduced these responses when precipitation was 32% below normal the following year. Cultivar ranking for mean single leaf area was generally the same as that for leaf size category: Grasslands Huia < Louisiana S‐1 < Regal. Although stolon length and growing point density were frequently greatest for Grasslands Huia, stolon survival of Grasslands Huia was no greater than that of the larger‐leafed cultivars. Despite varying effects of grazing method on growth and morphology, stolon survival of white clover was always greater under rotational stocking.

The medication of 582 patients taking insulin or oral hypoglycaemic agents has been analysed. A characterization is given of the patients and their. antidiabetic medication. Subsequently, a description of the use of cardiovascular drugs, in comparison with an age-matched control group, is presented. The diabetic population investigated has an average age of 67 years. Most cardiovascular agents, with the exception of thiazide diuretics, are used to a larger extent in the diabetic group in comparison with the control group. Non-selectiveβ-blockers, possibly hazardous in patients with diabetes mellitus, appear to be prescribed without restriction in the diabetic patients investigated. The results of this study suggest that the choice of drugs for the treatment of cardiovascular co-morbidity in patients with diabetes mellitus can be improved.

In this article the effect of vitamin E on two extrapyramidal disorders, tardive dyskinesia and Parkinson's disease, is reviewed. After a brief description of the symptoms, the current hypotheses for the pathogenesis of these diseases are described. A summary of the clinical research that has been done to establish the effectiveness of vitamin E is given. In tardive dyskinesia four clinical trials (double-blind, placebo-controlled) showed improvement in the symptoms with vitamin E in doses of up to 1,600 IU/day. Preliminary studies concerning Parkinson's disease suggested that vitamin E (2,000 IU/day) probably cannot prevent the development of the disease. It was suggested that vitamin E is able to slow the progression of the illness. The results from a large double-blind, placebocontrolled clinical trial, however, did not show any beneficial effect of vitamin E in Parkinson's disease.

This study presents the results of an analysis of the pharmacy records of 778 patients with asthma or chronic obstructive lung diseases. The high percentage of patients taking oral corticosteroids was striking. Inhaledβ-agonists for use as needed have been prescribed to only a minority of patients using these agents. Only half of the patients onβ-agonists used inhaled corticosteroids prophylactically. Drug interactions capable of causing changes in plasma theophylline concentrations appeared in only a small number of patients. The results from studies like the one presented here can provide valuable data to be used for further discussion between physicians and pharmacists about rational drug therapy.

Efforts to improve persistence of white clover (Trifolium repensL.) in the southeast USA would benefit from knowledge of annual growth patterns and associated periods of environmental stress. Our objective was to determine seasonal changes in morphological traits that contribute to plant growth and persistence among adapted cultivars and germplasm. ‘Louisiana S‐l’, ‘Osceola’, Brown Loam Synthetic No. 2 germplasm, and Southern Regional Virus Resistant germplasm were sown in common bermudagrass [Cynodon dactylon(L.) Pers.] pastures in September 1993 at Mississippi State and Newton, MS, and continuously stocked with cattle to maintain a 5‐ to 10‐cm sward height. Stolon length, viability of axillary buds, and seedling numbers were measured monthly for the next 2 to 3 yr. Stolon length of all entries increased to a maximum by June before declining to a minimum in October. Peak stolon production in the first, second, and third year after seeding at Mississippi State was 42, 123, and 59 m m−2, respectively. There were no monthly differences among the four entries for proportion of stolon nodes having elongated, viable, or nonviable axillary buds at either location. The proportion of nodes with elongated buds increased from 10 to 20% in October to 45% in March before declining during the spring. An increase in elongated buds during early summer preceded the fall decline. Number of volunteer seedlings ranged from 10 to 1870 m−2during the year, but any positive influence on stand persistence was not apparent. The cyclical trends for axillary bud viability indicate continued potential for vegetative persistence, particularly in the winter and spring, but the longterm decline in stolon length of all entries suggests that selection for different characters was not associated with improved persistence.

White clover (Trifolium repensL.) stands commonly decline within 2 to 3 yr after establishment, due to insects, fungi, nematodes, viruses, and other factors. This study determined the effect of application of insecticide and fungicide, and infestation of southern root‐knot nematode, Meloidogyne incognita(Kofoid & White) Chitwood, alone and in all combinations, on white clover persistence, yield, and crude protein (CP) concentration. The insecticide was cypermethrin [(±)‐α‐cyano‐3‐phenoxy benzyl (±)‐cis,trans‐ 3‐(2,2‐ dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylate] and the fungicide was benomyl [methyl l‐(butylcarbamoyl)‐2‐benzimidazole‐carbamate]. ‘Regal’ white clover was grown on a Marietta fine sandy loam (fine‐loamy, siliceous, thermic Fluvaquentic Eutrochrept) for 3 yr after establishment in 1986. No effects of the treatments on yield, stand, or CP were observed in 1987. In 1988 and 1989, yields were 52 to 85% greater in cypermethrin‐treated plots, 12% greater (1988 only) in benomyl‐treated plots, and 6 to 17% lower in M. incognita‐infested plots compared with untreated plots. The number of stolons per meter was 27 to 39% greater in cypermethrin‐treated plots, 20% greater (1988 only) in benomyl‐treated plots, and 12 to 20% lower in M. incognita‐infested plots, compared with untreated plots. All treatments had little effect on CP concentration. Fewer Sitona hispidulusFab‐larvae were found in the cypermethrin‐treated than untreated plots in 1989. White clover decline in the field was not due to any synergistic interactions between the factors evaluated in this study. When stresses such as insect, fungi, nematode, or virus are present and limit white clover growth, selection for resistance to these stresses should contribute to improved stand longevity and production of white clover.

Defoliation during the early stages of seedling development can influence growth of white clover (Trifolium repensL.). Our objective was to determine the response of cultivars with diverse leaf sizes to defoliation across a range of seedling growth stages. ‘Regal’ (large‐leaf), ‘Louisiana S‐1’ (medium‐large‐leaf), ‘Grasslands Huia’ (medium‐smallleaf), and ‘Aberystwyth S184’ (small‐leaf) were grown in the greenhouse and were initially clipped to remove all leaf (except cotyledons) and petiole tissue (1.0‐cm stubble) when seedlings attained a unifoliolate leaf or one, two, four, and eight trifoliolate leaves. Seedlings were subsequently clipped in the same manner every 7 or 28 d for the next 28 d. Plant response to defoliation was assessed 7, 14, 21, and 28 d after the last clipping. Seedling shoot dry weight of all cultivars increased linearly in response to initial leaf stage when subsequent clipping occurred every 7 d after the initial defoliation. When subsequent clipping was delayed 28 d, defoliation after the four‐trifoliolate stage did not influence shoot weight of any cultivar except Regal. Despite fewer numbers of leaves after regrowth, seedling leaf area of Regal was always greater than that of the other cultivars. Number of stolon branches of Regal and Louisiana S‐1 increased in response to leaf stage at initial defoliation (0.15 branches stage−1), while that of Grasslands Huia and Aberystwyth S184 was relatively unchanged after the four‐ to six‐trifoliolate stage. Permitting white clover seedlings to attain advanced leaf stages before initial defoliation and increasing the time interval before subsequent defoliation will enhance seedling growth and potential survival.

Near infrared reflectance Spectroscopy (NIRS) technology needs verification as to its utility for forages that represent diverse species, environments, and managements. Our objectives were to determine whether single NIRS calibration equations could reliably assess components of the feeding quality of alfalfa (Medicago salivaL.) grown to a range of maturities in several environments and whether single equations could be developed to simultaneously analyze components of the quality of total forage and plant parts of alfalfa, birdsfoot trefoil (Lotus cornieulattisL.), red clover (Trifolium pratenseL.), and white clover (Trifolium repensL.). In the first experiment, we assayed four forage quality components in 234 alfalfa samples from eight cutting schedules of two cultivars grown in two locations in each of 2 years. In Exp. II, we assayed five quality components in 167 samples of total forage and plant parts selected from seven harvests from two growth periods of two cultivars of each of four perennial legume species. Calibration equations for in vitro digestible dry matter (IVDDM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) were obtained by multiple linear regression of known conventional laboratory assay values on NIR spectra from up to 204 samples using a scanning monochromator NIR spectre‐computer system. Equations were validated with up to 49 additional samples that had been selected from the original populations. From three to nine wavelengths were required to develop the best calibration equations for the various quality components. The squared coefficients of determination (R2) of these equations ranged from 0.93 to 0.99. These equations allowed NIRS analysis of quality values in verification samples within standard errors (dag/kg) of 1.56 to 2.06 for IVDDM, 0.42 to 1.0 for CP, 1.46 to 2.23 for NDF, 1.30 to 1.70 for ADF, and 0.63 for ADL. We concluded that our NIRS system can quickly evaluate the feeding quality of perennial legumes to a degree of accuracy similar to that of laborious conventional analyses and that several species can be evaluated simultaneously with single calibration equations nearly as well as can single species.

A double-cavity optical configuration designed to investigate the sensitivity of intracavity absorption in a cw multimode dye laser is reported. The configuration consists of two optical cavities coupled together through a common partially transmitting mirror. An atomic beam of sodium is used as a low-density absorber to compare the sensitivity of a double-cavity configuration with that of a single cavity. The results are that the sensitivity of the double-cavity system is about half of that obtained with the usual single cavity. An interpretation of the results is made in terms of the super-regen model of intracavity absorption.

While clover (Trifolium repensL.) is often evaluated under clipping during selection of germplasm but is ultimately utilized in grazed pastures. The objective of this study was to determine the effect of defoliation method on morphological characters that serve as selection criteria for improving white clover productivity and persistence. Vegetative clones of 14 plants of Southern Regional Virus Resistant germplasm were space‐planted in a common bermudagrass [Cynodon dactylon(L.) Pers.] sward in each of 2 yr on a Savannah fine sandy loam (fine‐loamy, siliceous, thermic Typic Fragiudnlt). Clones were defoliated the following year by continuous stocking with cattle or by clipping or rotational stocking on a monthly basis. Lateral plant spread of all clones increased from April to June, but declined from July to October due to death of stolon apices, and was reduced up to 50% by continuous stocking compared with clipping and rotational stocking. In July, plant leaf area, stolon length, and number of stolon apices of all clipped and rotationally‐stocked clones were twice that of continuously‐stocked clones. Morphological response to defoliation method in October, however, was genotype‐dependent; clones that exhibited superior growth in response to one defoliation method did not exhibit the same response to either of the other methods. The differential effect of defoliation method on white clover morphology demonstrates the sensitivity of these characters to harvest management, and because of their association with persistence, the need to evaluate germplasm in the environment in which it will be utilized.