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Alien limb refers to movements that seem purposeful but are independent of patients' reported intentions. Alien limb often co-occurs with apraxia in the corticobasal syndrome, and anatomical and phenomenological comparisons have led to the suggestion that alien limb and apraxia may be causally related as failures of goal-directed movements. Here, we characterised the nature of alien limb symptoms in patients with the corticobasal syndrome (n = 30) and their relationship to limb apraxia. Twenty-five patients with progressive supranuclear palsy Richardson syndrome served as a disease control group. Structured examinations of praxis, motor function, cognition and alien limb were undertaken in patients attending a regional specialist clinic. Twenty-eight patients with corticobasal syndrome (93%) demonstrated significant apraxia and this was often asymmetrical, with the left hand preferentially affected in 23/30 (77%) patients. Moreover, 25/30 (83%) patients reported one or more symptoms consistent with alien limb. The range of these phenomena was broad, including changes in the sense of ownership and control as well as unwanted movements. Regression analyses showed no significant association between the severity of limb apraxia and either the occurrence of an alien limb or the number of alien limb phenomena reported. Bayesian estimation showed a low probability for a positive association between alien limb and apraxia, suggesting that alien limb phenomena are not likely to be related to severity apraxia. Our results shed light on the phenomenology of these disabling and as yet untreatable clinical features, with relevance to theoretical models of voluntary action. [ABSTRACT FROM AUTHOR]

Shedding of the endothelial glycocalyx precedes leukocyte activation and adherence in acute inflammation. Rapid administration of crystalloid or colloid fluids for treating hemorrhagic shock may cause endothelial glycocalyx shedding, thereby increasing inflammation. This study aimed to compare the effect of different fluid treatments in a canine shock model on glycocalyx biomarker, hyaluronan, and inflammatory biomarkers. Greyhound dogs under general anesthesia subject to hemorrhage for 60 min were given 20 mL kg−1 of either fresh whole blood (FWB), hydroxyethyl starch (HES) 130/0.4, 4% succinylated gelatin (GELO), or 80 mL kg−1 of isotonic crystalloid (CRYST) over 20 min (n = 6 per group). Plasma biomarkers hyaluronan, interleukin (IL) 6, 8, 10, tumor necrosis factor-α, monocyte chemoattractant protein-1, keratinocyte chemokine-like, and atrial natriuretic peptide were measured at baseline, end of hemorrhage (Shock), end of fluid administration (T20), and then 40 (T60), 100 (T120), and 160 (T180) minutes later. Biomarker concentrations were compared between groups using the Kruskal-Wallis test or Fisher’s exact test (measurable versus unmeasurable) (significance set at P < 0.05). Hyaluronan concentration peaked early in the CRYST group at T20, compared to HES (P = 0.005) and GELO (P = 0.018), and later in the GELO group at T60, compared to FWB (P < 0.001). The CRYST group had significantly more samples with measurable IL6 at T180 (P = 0.015), compared to GELO, and IL10 at T60, T120, and T180 (all P = 0.015), compared to FWB. There were no significant differences in other biomarker concentrations. In conclusion, rapid large-volume crystalloid administered for hemorrhagic shock was associated with increased hyaluronan and a greater inflammatory response. [ABSTRACT FROM AUTHOR]

Partial resistance quantitative trait loci (QTLs) Rphq11 and rphq16 against Puccinia hordei isolate 1.2.1 were previously mapped in seedlings of the mapping populations Steptoe/Morex and Oregon Wolfe Barleys, respectively. In this study, QTL mapping was performed at adult plant stage for the two mapping populations challenged with the same rust isolate. The results suggest that Rphq11 and rphq16 are effective only at seedling stage, and not at adult plant stage. The cloning of several genes responsible for partial resistance of barley to P. hordei will allow elucidation of the molecular basis of this type of plant defence. A map-based cloning approach requires to fine-map the QTL in a narrow genetic window. In this study, Rphq11 and rphq16 were fine-mapped using an approach aiming at speeding up the development of plant material and simplifying its evaluation. The plant materials for fine-mapping were identified from early plant materials developed to produce QTL-NILs. The material was first selected to carry the targeted QTL in heterozygous condition and susceptibility alleles at other resistance QTLs in homozygous condition. This strategy took four to five generations to obtain fixed QTL recombinants (i.e., homozygous resistant at the Rphq11 or rphq16 QTL alleles, homozygous susceptible at the non-targeted QTL alleles). In less than 2 years, Rphq11 was fine-mapped into a 0.2-cM genetic interval and a 1.4-cM genetic interval for rphq16. The strongest candidate gene for Rphq11 is a phospholipid hydroperoxide glutathione peroxidase. Thus far, no candidate gene was identified for rphq16. [ABSTRACT FROM AUTHOR]

Readers of chest radiographs often comment on the presence of osteoporosis. We have hypothesized that diagnoses of osteoporosis from chest films are not reliable even when made by experienced radiologists. To test this hypothesis, we had nine radiologists estimate the degree of bone density seen on 45 lateral chest films. We compared their estimates of bone density to the results of dual photon bone densitometry of the lumbar spine. We found that there was little ability to accurately diagnose osteoporosis by chest film since the group of nine readers achieved accuracies ranging from 0.59 to 0.64. Therefore, we feel it is unjustified to comment upon the presence or absence of osteoporosis on the basis of chest films. [ABSTRACT FROM AUTHOR]

This review describes the properties and regulation of the membrane transport proteins which supply the mammary gland with aminonitrogen to support metabolism under different physiological conditions (i.e. pregnancy, lactation and involution). Early studies focussed on characterising amino acid and peptide transport pathways with respect to substrate specificity, kinetics and hormonal regulation to allow a broad picture of the systems within the gland to be established. Recent investigations have concentrated on identifying the individual transporters at the molecular level (i.e. mRNA and protein). Many of the latter studies have identified the molecular correlates of the transport systems uncovered in the earlier functional investigations but in turn have also highlighted the need for more amino acid transport studies to be performed. The transporters function as either cotransporters and exchangers (or both) and act in a coordinated and regulated fashion to support the metabolic needs of the gland. However, it is apparent that a physiological role for a number of the transport proteins has yet to be elucidated. This article highlights the many gaps in our knowledge regarding the precise cellular location of a number of amino acid transporters within the gland. We also describe the role of amino acid transport in mammary cell volume regulation. Finally, the important role that individual mammary transport proteins may have in the growth and proliferation of mammary tumours is discussed. [ABSTRACT FROM AUTHOR]

Impending land-use change, including agricultural intensification, is increasingly threatening biodiversity in traditional rural landscapes. To ensure the persistence of species that are vulnerable to land-use change it is necessary to identify and protect high quality habitat before species start to decline. Given that many potentially vulnerable species are still widespread in traditional rural landscapes, it is difficult to identify particularly important locations for such species. Presence-absence data on a given species may have limited application in such cases. As an alternative to presence-absence data, we investigated the influence of environmental variables on the physiological body condition of Bombina variegata (yellow-bellied toad) in a traditional rural landscape in Transylvania, Romania. The species is internationally endangered but remains common throughout our study area. Based on body condition measurements of 550 toads from 60 ponds, we found that toads in forest ponds had significantly better body condition than those in pasture ponds, indicating that forest landscapes provided particularly high quality habitat. We suggest that measures such as body condition-in addition to distribution data-could have considerable application in identifying high quality habitat for other species that are still widespread in traditional landscapes, but have declined in modernised, but otherwise similar landscapes. [ABSTRACT FROM AUTHOR]

This article examines why an organization might wish to manage workplace romance, and describes a number of alternative approaches to managing dating. At first sight the ethics of dating bans balances the need to protect female employees from harassment against employee rights to privacy and freedom of association - a rights versus rights issue. However, dating bans seem not to be directed at protecting female employees from harm, but rather protect employers from sexual harassment liability claims - an employer self-interest versus employee rights issue. This article advocates a consequentialist approach to the problem, via the factoring in of other harms caused by prohibiting workplace romance. Given that most workplace romances end up in marriage or long-term partnerships, a ban on workplace romance is argued to be antisocial. The incidence of sexual harassment is very low in comparison to the number of long-term relationships initiated in the workplace. This article concludes by citing examples of firms that encourage romance, showing that is feasible to manage any resulting problems within these firms' existing conflict of interest and sexual harassment rules. [ABSTRACT FROM AUTHOR]

The phosphoinositide3-kinase (PI3K)/Akt and downstream mammalian target of rapamycin complex 1 (mTORC1) signalling cascades promote normal growth and are frequently hyperactivated in tumour cells. mTORC1 is also regulated by local nutrients, particularly amino acids, but the mechanisms involved are poorly understood. Unexpectedly, members of the proton-assisted amino-acid transporter (PAT or SLC36) family emerged from in vivo genetic screens in Drosophila as transporters with uniquely potent effects on mTORC1-mediated growth. In this study, we show the two human PATs that are widely expressed in normal tissues and cancer cell lines, namely PAT1 and PAT4, behave similarly to fly PATs when expressed in Drosophila. Small interfering RNA knockdown shows that these molecules are required for the activation of mTORC1 targets and for proliferation in human MCF-7 breast cancer and HEK-293 embryonic kidney cell lines. Furthermore, activation of mTORC1 in starved HEK-293 cells stimulated by amino acids requires PAT1 and PAT4, and is elevated in PAT1-overexpressing cells. Importantly, in HEK-293 cells, PAT1 is highly concentrated in intracellular compartments, including endosomes, wherein mTOR shuttles upon amino-acid stimulation. Therefore our data are consistent with a model in which PATs modulate the activity of mTORC1 not by transporting amino acids into the cell but by modulating the intracellular response to amino acids. [ABSTRACT FROM AUTHOR]

To test whether the rabbit proton-coupled peptide transporter PepT1 is a multimer, we have employed a combination of transport assays, luminometry and site-directed mutagenesis. A functional epitope-tagged PepT1 construct (PepT1-FLAG) was co-expressed in Xenopus laevis oocytes with a non-functional but normally trafficked mutant form of the same transporter (W294F-PepT1). The amount of PepT1-FLAG cRNA injected into the oocytes was kept constant, while the amount of W294F-PepT1 cRNA was increased over the mole fraction range of 0 to 1. The uptake of [3H]- d-Phe- l-Gln into the oocytes was measured at pHout 5.5, and the surface expression of PepT1-FLAG was quantified by luminometry. As the mole fraction of injected W294F-PepT1 increased, the uptake of d-Phe- l-Gln decreased. This occurred despite the surface expression of PepT1-FLAG remaining constant, and so we can conclude that PepT1 must be a multimer. Assuming that PepT1 acts as a homomultimer, the best fit for the modelling suggests that PepT1 could be a tetramer, with a minimum requirement of two functional subunits in each protein complex. Western blotting also showed the presence of higher-order complexes of PepT1-FLAG in oocyte membranes. It should be noted that we cannot formally exclude the possibility that PepT1 interacts with unidentified Xenopus protein(s). The finding that PepT1 is a multimer has important implications for the molecular modelling of this protein. [ABSTRACT FROM AUTHOR]

The amelogenin proteins regulate enamel mineral formation in the developing tooth. The human AMELX gene, which encodes the amelogenin proteins, is located within an intron of the Arhgap6gene. ARHGAP6 encodes a RhoGAP, which regulates activity of RhoA, a small G protein involved in intracellular signal transduction. Mice were generated in which the entire ARHGAP6 gene was deleted by Cre-mediated recombination, which also removed the nested AmelX gene. Enamel from these mice appeared chalky white, and the molars showed excessive wear. The enamel layer was hypoplastic and nonprismatic, whereas other dental tissues had normal morphology. This phenotype is similar to that reported for AmelX null mice, which have a short deletion that removed the region surrounding the translation initiation site, and resembles some forms of X-linked amelogenesis imperfecta in humans. Analysis of the enamel from the Arhgap6/AmelX-deleted mice verifies that the AmelX gene is nested within the murine Arhgap6 gene and shows that removal of the entire AmelX gene leads to a phenotype similar to the earlier AmelX null mouse results, in which no amelogenin protein was detected. However, an unusual layer of aprismatic enamel covers the enamel surface, which may be related to the 1.1-Mb deletion, which included Arhgap6 in these mice. [ABSTRACT FROM AUTHOR]

We have applied enzyme kinetic analysis to electrophysiological steady-state data of Zhou et al. (Zhou, J.J., Trueman, L.J., Boorer, K.J., Theodoulou, F.L., Forde, B.G., Miller, A.J. 2000. A high-affinity fungal nitrate carrier with two transport mechanisms. J. Biol. Chem. 275:39894-9) and to new current-voltage-time records from Xenopus oocytes with functionally expressed NrtA (crnA) 2H+-NO3- symporter from Emericella (Aspergillus) nidulans. Zhou et al. stressed two Michaelis-Menten (MM) mechanisms to mediate the observed nitrate-induced currents, I(NO3-). We show that a single straightforward reaction cycle describes the data well, pointing out that during exposure to external substrate, S = (2H+ + NO3-)o, the product concentration inside, [P] = [H+]i(2) x [NO3-]i, may rise substantially near the plasma membrane, violating the condition [P] << [S] for MM kinetics. Here, [P] and its changes during experimentation are treated explicitly. K(1/2) approximately 20 microM for I(NO3-) at pHo from Zhou et al. is confirmed. According to our analysis, NrtA operates between about 0.2 and 0.6 of the electrical distance in the membrane (outside 0, inside 1). In absence of thermodynamic gradients, the predominant orientation of the binding site(s) is probably inwards. The activity of the enzyme is sensitive to the transmembrane voltage, V, with an apparent gating charge of +1.0 +/- 0.5 for inactivation, and transition probabilities of 0.3-1.3 s(-1) at V = 0. This gating mode impedes loss of cellular NO3- during depolarization. [ABSTRACT FROM AUTHOR]

We propose an efficient, scalable, certificationbased key recovery system that is a hybrid of the key escrow and key encapsulation techniques. The proposed key recovery system is highly flexible and can be employed in a variety of policy environments. It possesses the properties required for commercial key recovery systems. We demonstrate the claims by comparing the computation and communication requirements for our proposal with a key recovery solution implemented by IBM. [ABSTRACT FROM AUTHOR]

The effect of l-arginine on transepithelial ion transport was examined in cultured M-1 mouse renal cortical collecting duct (CCD) cells using continuous short circuit current (ISC) measurements in HCO3-/CO2 buffered solution. Steady state ISC averaged 73.8 ± 3.2 μA/cm2 (n= 126) and was reduced by 94 ± 0.6% (n= 16) by the apical addition of 100 μm amiloride. This confirms that the predominant electrogenic ion transport in M-1 cells is Na+ absorption via the epithelial sodium channel (ENaC). Experiments using the cationic amino acid l-lysine (radiolabeled) as a stable arginine analogue show that the combined activity of an apical system y+ and a basal amino acid transport system y+L are responsible for most cationic amino acid transport across M-1 cells. Together they generate net absorptive cationic amino acid flux. Application of l-arginine (10 mm) either apically or basolaterally induced a transient peak increase in ISC averaging 36.6 ± 5.4 μA/cm2 (n= 19) and 32.0 ± 7.2 μA/cm2 (n= 8), respectively. The response was preserved in the absence of bath Cl- (n= 4), but was abolished either in the absence of apical Na+ (n= 4) or by apical addition of 100 μm amiloride (n= 6). l-lysine, which cannot serve as a precursor of NO, caused a response similar to that of l-arginine (n= 4); neither L-NMMA (100 μm; n= 3) nor L-NAME (1 mm; n= 4) (both NO-synthase inhibitors) affected the ISC response to l-arginine. The effects of arginine or lysine were replicated by alkalinization that mimicked the transient alkalinization of the bath solution upon addition of these amino acids. We conclude that in M-1 cells l-arginine stimulates Na+ absorption via a pH-dependent, but NO-independent mechanism. The observed net cationic amino acid absorption will counteract passive cationic amino acid leak into the CCD in the presence of electrogenic Na+ transport, consistent with reports of stimulated expression of Na+ and cationic amino acid transporters by aldosterone. [ABSTRACT FROM AUTHOR]

The cotransport of protons and peptides is now recognised as a major route by which dietary nitrogen is absorbed from the intestine, and filtered protein reabsorbed in the kidney. Recently, molecular biology has had a very substantial impact on the study of peptide transport, and here we review the molecular and functional information available within the framework of physiology. To this end we consider not only the mammalian peptide transporters and their tissue distribution and regulation but also those from other species (including Caenorhabditis elegans) which make up the proton-dependent oligopeptide transport superfamily. In addition, understanding the binding requirements for transported substrates may allow future design and targeted tissue delivery of peptide and peptidomimetic drugs. Finally, we aim to highlight some of the less well understood areas of peptide transport, in the hope that it will stimulate further research into this challenging yet exciting topic. [ABSTRACT FROM AUTHOR]

The long held promise of using volume holography to deliver high performance optical storage is reviewed. The problems, which limited the development for many years, are accessed. Finally, we describe a series of innovations, which may make the technology viable at last. [ABSTRACT FROM AUTHOR]

The article focuses on the surface antigen CD98(4F2). The article adds that this antigen belongs to a group of approximately two hundred proteins at the surface of leukocytes that are thought to be important for their function in the immune response, by specifying their migration, cell interactions and the signal transduction mechanisms that lead to lymphocyte activation. Following the discovery of CD98(4F2) as a surface antigen in lymphocytes the antigen was found to be present in all established human tissue culture cell lines tested and in most malignant human cells.

We have screened the elastin gene for mutations responsible for supravalvular aortic stenosis (SVAS) in two large, independently collected families with isolated (nonsyndromic) SVAS. By single-strand conformation polymorphism and heteroduplex analysis, we have identified a C to G transversion within the acceptor splice site of exon 16 in SVAS patients from both families. This mutation segregates in both families with high penetrance of SVAS, and all affected individuals carry the mutation. Haplotype analysis by using closely linked polymorphisms, including a previously unreported BfaI restriction fragment length polymorphism within the 3’-UTR of the elastin gene, indicates that the mutations found in the two apparently non-overlapping kindreds are identical by descent. To study the effect of the mutation on the expression of the mutant allele, we have established a primary skin fibroblast culture from one of the affected individuals. Reverse transcription/polymerase chain reaction analysis of elastin mRNA species indicates that the mutation results in two abnormal elastin mRNA species. One mutant elastin mRNA is generated by the activation of a cryptic splice site that lies within intron 15 and that adds 44 bp of intronic sequence to the sequence encoded by exon 16. This insertion creates a frame shift that results in a 59-amino-acid-long abnormal protein sequence and leads to a termination codon in the mRNA sequence encoded by exon 17. The smaller abnormal mRNA species arises as a consequence of the skipping of exon 16. This study demonstrates, for the first time, the expression of mutant alleles of the elastin gene in patients with isolated SVAS. [ABSTRACT FROM AUTHOR]

The proton dependence of the transport of three labelled, hydrolysis-resistant synthetic dipeptides carrying a net charge of −1, 0 or +1 has been investigated in a brush border membrane vesicle preparation obtained from rat renal cortex. Cross-inhibition studies are consistent with the transport of all peptides studied being through a single system. The extent and time course of uptake in response to an inwardly directed electrochemical gradient of protons differed for each peptide. For the cationic peptide D-Phe- L-Lys this gradient did not stimulate the initial rate of uptake, while for the neutral dipeptide D-Phe- L-Ala and the anionic peptide D-Phe- L-Glu stimulation was observed. However, the effect on D-Phe- L-Glu was more marked than that on D-Phe- L-Ala and the proton activation differed for these two peptides. The calculated Hill coefficients for the two proton-dependent peptides were 1.14±0.16 and 2.15±0.10 for D-Phe- L-Ala and D-Phe- L-Glu, respectively, providing evidence that the stoichiometry of proton: peptide cotransport is different for each peptide (0∶1, 1∶1 and 2∶1 for D-Phe- L-Lys, D-Phe- L-Ala and D-Phe- L-Glu respectively); studies on energetics are compatible with this conclusion. The physiological and molecular implications of this model are discussed, as are the applicability of the conclusions to secondary active transport systems more generally. [ABSTRACT FROM AUTHOR]

We have studied chloride influx and efflux in a highly purified preparation of type n cells freshly isolated from adult guinea-pig lung using Cl. Chloride uptake was time-dependent, saturable (K<10 mM) and was inhibited by 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS; K≈80 μM). In the absence of external chloride (substituted by gluconate), Cl uptake exhibited an overshoot above equilibrium. The rate of Cl entry was strongly inhibited by addition of external nitrate; sulphate was a weaker inhibitor. Cl efflux was stimulated by external bromide > bicarbonate ≥ chloride ≥ citrate; and was inhibited by proprionate > acetate > oxalate. Although the 'chloride channel blocker' 4-nitro-2-(3-phenylpropylamino)benzoate (0.14 mM) caused an inhibition, Cl influx did not appear to be electrogenic. These data are compatible with the existence of a substantial electroneutral anionexchange pathway for chloride transport in freshly isolated adult type II pneumocytes. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the methyl parathion (MEP) and fluorescent dye penetration in simulated spill and the effects of surfactant in dye penetration. The study used gas chromatography (GC) and a fluorescent particle (FP) method to predict the fabrics' barrier performance. Results show that dye's average recovery from the cotton knit collector layer was 93.7% while its surfactant on fabric pretreated with surfactant were not significant.

Feeding experiments were conducted at Palmer Station from December 1985 to February 1986 to examine the potential role of copepod prey as an alternative food source for Euphausia superba. Copepod concentration, copepod size, phytoplankton concentration, the duration of krill starvation and the volume of experimental vessels were altered to determine effects on ingestion and clearance rates. Krill allowed to feed on phytoplankton and copepods in 50-litre tubs showed greatly increased feeding rates relative to animals feeding in the much smaller volumes of water traditionally used for krill-feeding studies. Clearance rates on copepods remained constant over the range of concentrations offered, but clearance rates on phytoplankton increased linearly with phytoplankton concentration. Feeding rates increased when larger copepods were offered and when krill were starved for two weeks prior to experiments. Clearance rates of krill feeding on copepods were higher than, but not correlated with, their clearance rates on phytoplankton in the same vessel. E. superba may have a distinct mechanism for capturing copepods, perhaps through mechanoreception. Although our observed clearance rate of 1055 ml krill h indicates that krill can feed very efficiently on copepod prey, such feeding would meet less than 10% of their minimum metabolic requirements at the 'typical' copepod concentrations reported for Antarctic waters. However, substantial energy could be gained if krill fed on the patches of high copepod concentrations occasionally reported during the austral summer, or if krill and copepods were concentrated beneath the sea ice during the winter or spring months. Our results, indicating efficient feeding on zooplankton and higher clearance rates on phytoplankton than previously believed, represent a step towards balancing the energy budget of E. superba in Antarctic waters. [ABSTRACT FROM AUTHOR]

Elastin is the major component of elastic fibers in aortic tissue and has been suggested to be important for the stretch and recoil of the bladder. We have mapped the histologic distribution of elastin throughout the entire guinea-pig bladder as well as changes in the distribution of elastin during bladder-outlet obstruction. We used an animal model in which a jeweler's ring is placed around the urethra of the young guinea pig. As the animal grows, outlet obstruction is gradually induced, and the bladder gradually increases in total weight to as much as 8-fold that of controls. We localized the elastin histologically in normal and obstructed bladders by serially sectioning entire bladders and staining the sections with an elastin-specific stain, Verhoff-van Gieson stain (VVG). Surprisingly, we found that the elastin was predominantly localized only to the trigone of the bladder and that the elastin in this area was increased during obstruction. These results are consistent with the predominantly mesodermal embryologic origin of the trigone, since mesodermal tissues are more often associated with elastin expression. [ABSTRACT FROM AUTHOR]

Using the Conflict Tactics Scale, a random sample of 1471 Utah residential units was selected in 1986 to assess family violence. Results were compared with data from the Straus and Gelles (1986) United States national survey of family violence. Spousal violence rates in Utah households were slightly higher than those in the national survey. Income, employment status, education, family size, religiosity, marital power structure, and gender role orientation failed to differentiate spousal violence rates. Parent-to-child violence rates were less in Utah than in the national survey. Severe mother-to-child violence was influenced substantially by educational level, family size, employment status, and gender role orientation. High level of education for traditionally oriented mothers who are not employed was associated with severe physical violence toward their children. [ABSTRACT FROM AUTHOR]

The uptake of 3H-labeled choline by a suspension of isolated type II epithelial cells from rat lung has been studied in a Ringer medium. Uptake was linear for 4 min at both 0.1 microM and 5.0 microM medium choline; at 5 microM, only 10% of the label was recovered in a lipid fraction. Further experiments were conducted at the low concentration (0.1 microM), permitting characterization of the properties of high-affinity systems. Three fractions of choline uptake were detected: (i) a sodium-dependent system that was totally inhibited by hemicholinium-3 (HC-3); (ii) a sodium-independent uptake, when Na+ was replaced by Li+, K+ or Mg2+, inhibited by HC-3; (iii) a residual portion persisting in the absence of Na+ and unaffected by HC-3. Choline uptake was sigmoidally related to the medium Na+ concentration. Kinetic properties of the uptake of 0.1 microM 3H-choline in the presence and absence of medium Na+ were examined in two ways. (a) Inhibition by increasing concentrations of unlabeled choline (0.5-100 microM) was consistent with the presence of two Michaelis-Menten-type systems in the presence of Na+; a Na(+)-dependent portion (a mean of 0.52 of the total) had a K(m) for choline of 1.5 microM while K(m) in the absence of Na+ (Li+ substituting) was 18.6 microM. (b) Inhibition by HC-3 (0.3-300 microM) gave Ki values of 1.7 microM and 5.0 microM HC-3 for the Na(+)-dependent and -independent fractions. The apparent K(m) of the Na(+)-dependent uptake is lower than that reported previously for lung-derived cells and is in the range of the K(m) values reported for high-affinity, Na(+)-dependent choline uptake by neuronal cells. [ABSTRACT FROM AUTHOR]

Using dual-laser sorted chromosomes and spot-blot analysis, we have previously assigned genomic DNA sequences coding for human α1(IV) procollagen to chromosome 13 (Pihlajaniemi et al. 1985). By in situ hybridization to normal chromosomes and chromosomes with 13q deletions, we now report the localization of this gene to the terminal end of the long arm of chromosome 13. In addition, Southern and slot blot hybridization analysis clearly show that these genomic sequences are present only once per haploid genome. [ABSTRACT FROM AUTHOR]

We present a method for parametrizing heavy-meson semi-leptonic form factors using dispersion relations, and from it produce a two-parameter description of the B→B elastic form factor. We use heavy-quark symmetry to relate this function to $$\bar B \to D*\ell \bar v$$ form factors, and extract | V |=0.0355 from experimental data with a least-squares fit. Our method eliminates model-dependent uncertainties inherent in choosing a parametrization for the extrapolation of the differential decay rate to threshold. [ABSTRACT FROM AUTHOR]

Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leukocyte scan and 10 patients with negative scan showed no significant difference between the two groups for the Crohn's disease activity index, sedimentation rate, survival, complications, number of days in hospital, outpatient visits, or readmissions. Despite the apparent lack of statistical significance in Crohn's disease activity index, the scan was positive in nine of 16 patients with a Crohn's disease activity index more than 150, and none of three patients with Crohn's disease activity index less than 150. In the patients studied, there were no false-positive leukocyte scans. In nine of 10 patients with ileocolonic disease, scanning results correctly predicted the proper management. Six patients with positive scan and enteroclysis responded to medical treatment. Four patients had positive enteroclysis and negative scan; of these, three had radiographic features of chronic ileal stricture which was confirmed at operation. The results suggest that a negative delayed indium-111 leukocyte scan may he useful in diagnosis of chronic fibrotic ileal stricture. [ABSTRACT FROM AUTHOR]

Cl uptake by microvillus brush border membrane vesicles prepared from normal term human placenta has been studied using an ion exchange column assay and a novel method to correct for vesicle recovery. Uptake of this anion, which was largely into an osmotically active space, was time dependent with a half-time of approximately 4 min at 4°C. DIDS at a maximal inhibitory concentration inhibitedCl uptake by approximately 40%; furosemide (10 M) showed a similar degree of inhibition and the effects of the two drugs appeared not to be additive. Anions including Cl, Br, I, NO, salicylate and SCN reducedCl uptake, the latter two being the most potent; gluconate was without effect. Inhibition by maximal inhibitory concentrations of DIDS and the anions SCN and salicylate was not additive. Neither the DIDS-sensitive nor the SCN-sensitive component ofCl uptake was influenced by membrane potential; in contrast the inhibitor-insensitive component was increased by an inside positive membrane potential. These findings suggest that under the conditions employed an electroneutral anion exchange system is responsible for approximately half of the chloride flux across this plasma membrane. [ABSTRACT FROM AUTHOR]

A satisfactory method was developed for evaluating the holding characteristics of fasteners in bone. Using this method in over 100 tests, the ultimate pull-out forces and shear stresses were determined for two sizes of sheet-metal type of screws with various interference fits, for a commercial orthopedic self-tapping screw, and for two sizes of machine screws in tapped bone, each at five sections of equine metacarpus. The ultimate pull-out force was maximum at the midlength of the bone, and minimum at the distal end. In general, the failure mechanisms were bone-thread shear for low pull-out forces, bone splitting at intermediate pull-out forces, and bone fragmentation at high pull-out forces. The failure mechanisms of the bone indicate that orthopedic fasteners should possibly not be designed for maximum holding force. [ABSTRACT FROM AUTHOR]

The reported work is a part of an ongoing research program concerned with structural analysis of fractured long bone and methods of internal fixation. The stress-concentration factors for equine metacarpus bones containing greenstick fractures and 'through' fractures (surgically repaired) were determined for the compression, flexural and torsional modes of loading based on whole bone (unfractured) strengths. The greenstick type of fracture was simulated with saw cuts at the mid-span of the bone, and the parameters varied were depth of fracture and orientation of fracture. All specimens consisted of fresh dead bone which had been placed in a freezer within 4 hr after expiration. The maximum stress-concentration factors for the simulated greenstick fractures studied were about 3.4 for compression, 4.3 for torsion and 16 for flexure. The stressconcentration factors for fractured bones surgically repaired with commercial plates were about 3.0 for compression, 2.7 for torsion and 6.1 for flexure. [ABSTRACT FROM AUTHOR]

The literature on the vacuolar structure of the human syncytiotrophoblast is briefly reviewed. Personal observations based on light and electron microscopic investigations are described and illustrated. The nature of the different kinds of syncytial vacuolation is discussed. In particular dilated vacuoles, which may be very large indeed, receive special attention; situated adjacent to the syncytial nuclei they have been called 'juxtanuclear vacuoles'. They are directly continuous with the perinuclear spaces, and often receive tubular communications from the endoplasmic reticular system. The possible functional role of the syncytial vacuolar system is discussed in the light of the authors' findings and the related literature. [ABSTRACT FROM AUTHOR]

Lysine influx (2 μM) into activated human B and T lymphocytes through transport systems y and yL was measured. In activated T cells very substantial activation of system y was detected; system yL was also activated in these cells but with a slower time course and to a smaller extent. No stimulation of either system was found in activated B cells. The time course of activation of system y precisely matched the expression of the T cell early antigen gene described by MacLeod et al, 1990. The functional significance of these observations with respect to L-arginine transport and nitric oxide synthesis in activated T lymphocytes is discussed. [ABSTRACT FROM AUTHOR]

Structural defects in the human type 1 collagen genes are known to be the cause of several inherited disorders of connective tissue, such as osteogenesis imperfecta. The analysis and prenatal diagnosis of these disorders would be facilitated by establishing a set of polymorphic markers at these gene loci. We have previously reported the presence of an Msp 1 restriction fragment length polymorphism in the proα2(1) collagen genes of several Southern African populations (Grobler-Rabie et al., in press). This report describes the detection of a Bgl II and an EcoRI polymorphism in the proα2 gene of South African Blacks. [ABSTRACT FROM AUTHOR]

A foreword to "The Journal of Membrane Biology" is presented.

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