Search

The goal of this study was to examine whether hippocampal volume or resting-state functional connectivity (rsFC) patterns are associated with subjective memory decline (SMD) in cognitively normal aged adults. Magnetic resonance imaging data from 53 participants (mean age: 71.9 years) of the Boston University Alzheimer's Disease Center registry were used in this cross-sectional study. Separate analyses treating SMD as a binary and continuous variable were performed. Subfield volumes were generated using FreeSurfer v6.0, and rsFC strength between the head and body of the hippocampus and the rest of the brain was calculated. Decreased left whole hippocampal volume and weaker rsFC strength between the right body of the hippocampus and the default mode network (DMN) were found in SMD+. Cognitive Change Index score was not correlated with volumetric measures but was inversely correlated with rsFC strength between the right body of the hippocampus and 6 brain networks, including the DMN, task control, and attentional networks. These findings suggest that hippocampal rsFC patterns reflect the current state of SMD in cognitively normal adults and may reflect subtle memory changes that standard neuropsychological tests are unable to capture. [ABSTRACT FROM AUTHOR]

Igneous activity in the rear-arc of the Paleogene Urumieh–Dokhtar Magmatic Belt of Iran has to date been poorly studied. An example of such activity, Late Eocene potassic mafic to intermediate magmatic rocks in the Lahrud area of NW Iran, is the focus of this work. These lavas include olivine-bearing clinopyroxene-phyric basalts, analcime-bearing leucite–clinopyroxene-phyric basalts, andesites, and trachytes, and Paleocene–Early Eocene pyroclastic rocks. Monzo-syenite plugs (dated here at ∼37 Ma), clinopyroxene-phyric basaltic dikes, and leucite-bearing clinopyroxene-phyric basaltic dikes intrude older lavas and pyroclastic rocks. Olivine-bearing clinopyroxene-phyric basalts and analcime-bearing leucite–clinopyroxene-phyric basalts are characterized by large phenocrysts of olivine, clinopyroxene, leucite, and analcime. Clinopyroxene-rich enclaves and partially resorbed mantle xenoliths also occur. Olivine phenocrysts are zoned from high-Mg# cores (Mg# = 90) to Fe-rich rims (Mg# = 66). Clinopyroxene phenocrysts from the olivine-bearing clinopyroxene-phyric basalts, analcime-bearing leucite–clinopyroxene-phyric basalts and clinopyroxene crystals in the enclaves show complex oscillatory zoning, sieve textures, and resorption textures, but with systematic core–rim compositional trends. Their 87Sr/86Sr isotopic compositions measured in situ range from 0·7037 to 0·7068 (mean = 0·7052 ± 0·0004), suggesting negligible crustal assimilation during fractional crystallization. The Lahrud lavas are potassic and are enriched in light rare earth elements and large ion lithophile elements such as Th, Rb, K and U. High field strength elements (HFSE), such as Nb, are depleted in the olivine-bearing clinopyroxene-phyric basalts and analcime-bearing leucite–clinopyroxene-phyric basalts, but enriched in the trachytes and trachytic ignimbrites. The isotopic compositions vary: 87Sr/86Srt from 0·7045 to 0·7052, εNd(t) from +2·8 to +3·3, and εHf(t) from +7·2 to +7·7. The rocks have radiogenic lead 206Pb/204Pb from 18·66 to 18·76, 207Pb/204Pb from 15·58 to 15·62, and 208Pb/204Pb from 38·73 to 38·81. Modeling of major and trace elements using the MELTS algorithm indicates that the geochemical variations in the basaltic to andesitic rocks are reasonably explained by shallow fractional crystallization with some complications owing to source heterogeneity, crustal assimilation, and magma mixing. The isotopic data imply that partial melting of old sub-continental lithospheric mantle was not responsible for the Lahrud potassic magmas; Hf isotopes and Zr/Nb ratios suggest derivation from an enriched mantle wedge, whereas ratios of incompatible trace elements (e.g. La/Yb, Ba/La, Ce/Pb, Th/Yb) and high 87Sr/86Sr suggest mantle metasomatized by slab-derived fluids or melts dominated by a sediment component. Geochemical modeling using the Arc Basalt Simulator version 5 reveals that the HFSE-depleted, olivine-bearing, clinopyroxene-phyric basalts originated from a high-temperature mantle wedge (2·2 GPa, 1310°C) fluxed intensively (5%) by melts from a deep hot slab (6 GPa, 1000°C). The moderately HFSE-depleted, olivine-bearing, clinopyroxene-phyric basalts reflect melting of a lower-temperature mantle wedge (2·2 GPa, 1300°C) with a lesser amount of slab melt flux (4%) from a lower temperature and shallower slab (3 GPa, 866°C). In contrast, the leucite–clinopyroxene-phyric basalts and andesites are from a similar source to the moderately HFSE-depleted, olivine-bearing, clinopyroxene-phyric basalts (3 GPa, 866°C) but with a contribution from a lower temperature mantle wedge (2·2 GPa, 1270°C). During Late Eocene times, slab retreat and upper-plate extension occurred in the rear-arc region of the Urumieh–Dokhtar Magmatic Belt. The Lahrud potassic magmas were generated from a high-temperature mantle wedge, which resulted in melting of the slab; this slab melt flux further promoted melting of the mantle wedge. [ABSTRACT FROM AUTHOR]

The Cadomian orogen of NW Iran includes a series of metamorphic rocks with zircon U-Pb ages between ca 562 and 505 Ma (Ediacaran to middle Cambrian). The Ediacaran-Cambrian basement is intruded by a series of Late Eocene-Late Oligocene I-type granitic rocks. U-Pb geochronology, integrated with geochemical and isotopic data for the basement rocks in NW Iran, provides further evidence of a Cadomian (562-505 Ma) arc-related magmatic event lasting ∼ 60 Myr. Cadomian magmatism in Iran was a part of a ∼ 100 Myr long episode of subduction-related arc magmatism at the northern margin of Gondwana. Zircon Hf-isotope compositions show that during Cadomian magmatic arc activity, juvenile arc magmas interacted with reworked Archean crust to generate the Ediacaran-Cambrian igneous rocks. Our results document both inheritance of old zircons and the presence of zircons with juvenile signatures in NW Iran, suggesting that the geotectonic setting for the Cadomian rocks was an Ediacaran continental magmatic arc and probably a neighboring back-arc basin. The occurrence of Ediacaran ophiolitic slices in NW Iran may provide evidence of back-arc basin opening at that time. Cenozoic plutonism in NW Iran is part of an Eocene-Oligocene magmatic 'flare-up' along the Urumieh-Dokhtar Magmatic Belt in central Iran, which lasted for ca 30 Myr. The melts responsible for the formation of these rocks had an essentially juvenile signature with minor contamination by Archean to Cadomian middle-lower continental crust. Continuous convergence between Arabia and Iran was accompanied by the transition of SW Eurasia from a compressional to an extensional convergent plate margin in Eocene-Oligocene times, leading to orogenic collapse, core-complex formation, exhumation of Cadomian crust and a major increase in arc magmatism. [ABSTRACT FROM AUTHOR]

Pagan is one of the largest volcanoes along the Mariana arc volcanic front. It has a maximum elevation of 570 m (Mt. Pagan), but its submarine flanks descend to 2000–3000 m below sea level, and are unexplored. Bathymetric mapping and ROV Hyper-Dolphin dives (HPD1147 and HPD1148) on the submarine NE and SW flanks of Pagan were carried out during cruise NT10-12 of R.V. Natsushima in July 2010. There are no systematic compositional differences between subaerial lavas reported in the literature and differentiated submarine lavas collected in HPD1148, with <7 wt % MgO, suggesting they are derived from the same magmatic system. However, these differentiated lavas show complexities including magma mixing; thus we concentrate on magnesian submarine lavas (>7 wt % MgO). Twenty least-fractionated basalts (48·5–50 wt % SiO2) collected during HPD1147 extend to higher MgO (10–11 wt %) and Mg# (66–70) than the subaerial lavas. Olivine (up to Fo94) and spinel (Cr# up to 0·8) compositions suggest that these Pagan primitive magmas formed from high degrees of mantle melting. Two basalt types can be distinguished based on their geochemistry at similar (10–11 wt %) MgO; these erupted recently, 500 m apart. Both contain clinopyroxene and olivine phenocrysts and are referred to as COB1 and COB2. Lower TiO2, FeO, Na2O, K2O, incompatible trace element abundances, and Nb/Yb suggest that COB1 formed from higher degrees of mantle melting. In addition, light rare earth element (LREE) enrichment and higher Th/Nb in COB2 contrast with LREE depletion and lower Th/Nb in COB1. Higher Ba/Th and Ba/Nb and lower Th/Nb indicate that the main subduction addition in COB1 was dominated by hydrous fluid, whereas that in COB2 was dominated by sediment melt. Sr–Nd–Pb–Hf isotopes are also consistent with this interpretation. These observations suggest that the subduction component responsible for the greater degree of melting of the COB1 source was mostly hydrous fluid. The origin of such different metasomatic agents resulted in different primary magmas forming in the same volcano. Both hydrous fluid and sediment melt components may have unmixed from an originally homogeneous supercritical fluid in or above the subducting slab below the volcanic front. These may have been added separately to the mantle wedge peridotite (mantle diapir) and resulted in two neighboring but completely different primary magmas from the same diapir. Moreover, these primitive lavas suggest that even for intra-oceanic arcs assimilation–fractional crystallization is inevitable when these magmas evolve in the crust and, in addition, that phlogopite is present in their mantle residue and thus played an important role in their genesis. [ABSTRACT FROM PUBLISHER]

Hyaluronan is a high-molecular-weight glycosaminoglycan (GAG) prominent in the extracellular matrix. Emerging relatively late in evolution, it may have evolved to evade immune recognition. Chondroitin is a more ancient GAG and a possible hyaluronan precursor. Epimerization of a 4-hydroxyl in N-acetylgalactosamine in chondroitin to N-acetylglucosamine of hyaluronan is the only structural difference other than chain length between these two polymers. The axial 4-hydroxyl group extends out perpendicular from the equatorial plane of N-acetylgalactosamine in chondroitin. We suspect that this hydroxyl is a prime target for immune recognition. Conversion of a thumbs-up hydroxyl group into a thumbs-down position in the plane of the sugar endows hyaluronan with the ability to avoid immune recognition. Chitin is another potential precursor to hyaluronan. But regardless whether of chondroitin or of chitin origin, an ancient chondroitinase enzyme sequence seems to have been commandeered to catalyze the cleavage of the new hyaluronan substrate. The evolution of six hyaluronidase-like sequences in the human genome from a single chondroitinase as found in Caenorhabditis elegans can now be traced. Confirming our previous predictions, two duplication events occurred, with three hyaluronidase-like sequences occurring in the genome of Ciona intestinalis (sea squirt), the earliest known chordate. This was probably followed by en masse duplication, with six such genes present in the genome of zebra fish onwards. These events occurred, however, much earlier than predicted. It is also apparent on an evolutionary time scale that in several species, this gene family is continuing to evolve. [ABSTRACT FROM AUTHOR]

Chronic traumatic encephalopathy is a progressive tauopathy that occurs as a consequence of repetitive mild traumatic brain injury. We analysed post-mortem brains obtained from a cohort of 85 subjects with histories of repetitive mild traumatic brain injury and found evidence of chronic traumatic encephalopathy in 68 subjects: all males, ranging in age from 17 to 98 years (mean 59.5 years), including 64 athletes, 21 military veterans (86% of whom were also athletes) and one individual who engaged in self-injurious head banging behaviour. Eighteen age- and gender-matched individuals without a history of repetitive mild traumatic brain injury served as control subjects. In chronic traumatic encephalopathy, the spectrum of hyperphosphorylated tau pathology ranged in severity from focal perivascular epicentres of neurofibrillary tangles in the frontal neocortex to severe tauopathy affecting widespread brain regions, including the medial temporal lobe, thereby allowing a progressive staging of pathology from stages I–IV. Multifocal axonal varicosities and axonal loss were found in deep cortex and subcortical white matter at all stages of chronic traumatic encephalopathy. TAR DNA-binding protein 43 immunoreactive inclusions and neurites were also found in 85% of cases, ranging from focal pathology in stages I–III to widespread inclusions and neurites in stage IV. Symptoms in stage I chronic traumatic encephalopathy included headache and loss of attention and concentration. Additional symptoms in stage II included depression, explosivity and short-term memory loss. In stage III, executive dysfunction and cognitive impairment were found, and in stage IV, dementia, word-finding difficulty and aggression were characteristic. Data on athletic exposure were available for 34 American football players; the stage of chronic traumatic encephalopathy correlated with increased duration of football play, survival after football and age at death. Chronic traumatic encephalopathy was the sole diagnosis in 43 cases (63%); eight were also diagnosed with motor neuron disease (12%), seven with Alzheimer’s disease (11%), 11 with Lewy body disease (16%) and four with frontotemporal lobar degeneration (6%). There is an ordered and predictable progression of hyperphosphorylated tau abnormalities through the nervous system in chronic traumatic encephalopathy that occurs in conjunction with widespread axonal disruption and loss. The frequent association of chronic traumatic encephalopathy with other neurodegenerative disorders suggests that repetitive brain trauma and hyperphosphorylated tau protein deposition promote the accumulation of other abnormally aggregated proteins including TAR DNA-binding protein 43, amyloid beta protein and alpha-synuclein. [ABSTRACT FROM PUBLISHER]

Abstract: The Clock Drawing Test (CDT) is a common neuropsychological measure sensitive to cognitive changes and functional skills (e.g., driving test performance) among older adults. However, normative data have not been adequately developed. We report the distribution of CDT scores using three common scoring systems [Mendez, M. F., Ala, T., & Underwood, K. L. (1992). Development of scoring criteria for the Clock Drawing Task in Alzheimer''s Disease. Journal of the American Geriatrics Society, 40, 1095–1099; Cahn, D. A., Salmon, D. P., Monsch, A. U., Butters, N., Wiederholt, W. C., & Corey-Bloom, J. (1996). Screening for dementia of the Alzheimer type in the community: The utility of the Clock Drawing Test. Archives of Clinical Neuropsychology, 11(6), 529–539], among 207 cognitively normal elderly. The systems were well correlated, took little time to use, and had high inter-rater reliability. We found statistically significant differences in CDT scores based on age and WRAT-3 Reading score, a marker of education quality. We present means, standard deviations, and t- and z-scores based on these subgroups. We found that “normal” CDT performance includes a wider distribution of scores than previously reported. Our results may serve as useful comparisons for clinicians wishing to know whether their patients perform in the general range of cognitively normal elderly. [Copyright &y& Elsevier]

Abstract: The objective of the present study was to provide normative data for Trail Making Test (TMT) time to completion and performance errors among cognitively normal older adults, and to examine TMT error rates in conjunction with time scores for pre-clinical and clinical Alzheimer''s disease (AD) diagnostic decision-making. A sample of 526 individuals was classified into three diagnostic groups (normal controls, N =269; mild cognitive impairment, MCI, N =200; AD, N =57) by a multidisciplinary consensus conference. Results indicated that performance differed among the three groups for TMT A and B time scores as well as TMT B error rate. Diagnostic classification accuracy (i.e., sensitivity, specificity, and positive and negative predictive powers) is described for various combinations of the diagnostic groups. The findings show that TMT B time and errors are independently meaningful scores, and both therefore have clinical utility in assessing individuals referred for dementia evaluations. [Copyright &y& Elsevier]

Abstract: Neuropsychological impairment is common, yet variable, after coronary artery bypass grafting (CABG). Similar variability has been observed in other CNS-related diseases. Empirical findings in Alzheimer''s disease and HIV, among other areas, suggest cognitive reserve (CR) may mediate the cognitive impact of these diseases. The present study examined whether CR mediates neuropsychological outcome after CABG. Participants were 42 (N =42) individuals who underwent elective, normothermic CABG. Each was placed in high (n =22) or low (n =20) CR groups based on estimated premorbid intelligence and occupational attainment. All were administered neuropsychological tests preoperatively and at discharge. The total incidence of neuropsychological decline (66.7%) was not significantly different between CR groups. However, on working memory and executive function tests, specifically, the high CR group demonstrated greater post-operative decline compared to the low CR group. These data are considered in the context of a threshold model of CR theory. [Copyright &y& Elsevier]

Abstract: Objective: To clinically characterize performance on the Hooper Visual Organization Test (HVOT) among participants with mild cognitive impairment (MCI) and to identify naming and executive functioning correlates associated with HVOT performance among MCI participants and normal controls (NC). Background: The HVOT is a common neuropsychological instrument that measures visuospatial skills and agnosia. It has, however, been criticized for its multifactorial nature, as several studies have reported executive or language correlates of HVOT performance. To our knowledge, simultaneous comparison of executive functioning and language demands of the HVOT has never been performed among an older cohort. Methods: The HVOT, two tests of executive functioning [Trail Making Test, Part B (TMT-B), Controlled Oral Word Association (COWA)] and two tests of naming [abbreviated Boston Naming Test (BNT), Animal Naming] were administered to 222 NC, 166 MCI, and 68 Alzheimer''s disease (AD) individuals. Results: HVOT scores were significantly different between all three groups in the expected direction (AD

Abstract: The Driving Scenes test of the new Neuropsychological Assessment Battery (NAB; [Stern, R.A., & White, T. (2003a). Neuropsychological Assessment Battery. Lutz, FL: Psychological Assessment Resources, Inc.]) measures several aspects of visual attention thought to be important for driving ability. The current study examined the relationship between scores on the Driving Scenes test and on-road driving performance on a standardized driving test. Healthy participants performed significantly better on the Driving Scenes test than did very mildly demented participants. A correlation of 0.55 was found between the brief, office-based Driving Scenes test and the 108-point on-road driving score. Furthermore, the Driving Scenes test scores differed significantly across the driving instructor''s three global ratings (safe, marginal, and unsafe), and results of a discriminant function analysis indicated that the Driving Scenes test correctly classified 66% of participants into these groups. Thus, the new NAB Driving Scenes test appears to have good ecological validity for real-world driving ability in normal and very mildly demented older adults. [Copyright &y& Elsevier]

The Ueno Basalts of central Japan comprise a monogenetic volcanic cone complex that was active between 2·76 and 1·34 Ma. Basalts were erupted at more than 14 centers scattered over a region 40 km in diameter. Alkali basalt was erupted first, followed by sub-alkaline basalt. Quasi-concentric expansion of eruption centers coinciding with uplift and with decreasing alkalinity of the lavas suggests that Ueno magmatism originated from a mantle diapir as it mushroomed at the base of the lithosphere. Depleted asthenospheric mantle (alkali basalt), enriched lithospheric mantle (sub-alkaline basalt), and crustal components are identified as chemical end-members in the petrogenesis of the Ueno Basalts. Incompatible trace element abundances indicate that the Ueno alkali basalts are typical within-plate basalts, whereas the sub-alkaline basalts show strong affinities with normal arc lavas. Sr–Nd–Pb isotopic compositions indicate that the mantle source of the alkali basalts was more depleted than that of the sub-alkaline basalts. About 7% melting of asthenospheric mantle in the garnet-lherzolite stability field produced the primitive alkali basalts and 12% melting of spinel lherzolite within the subcontinental lithosphere produced the primitive sub-alkaline basalts. Isotopic compositions and fluid mobile/immobile element ratios broadly covary with SiO2 contents in the sub-alkaline suite, and increasing silica content is associated with stronger EMII (Enriched Mantle II) isotope affinities and fluid mobile element abundances. A progressive AFC (assimilation–fractional crystallization) model assuming assimilation of a low-K silicic melt reproduces the chemical variations observed in the sub-alkaline suite. Melting of a flattening mantle diapir at the base of the lithosphere is the dominant cause of Ueno magmatism, accompanied by the assimilation of older arc crust. [ABSTRACT FROM PUBLISHER]

Background/methods: The treatment of psoriasis with high-dose exposure to oral psoralen and ultraviolet-A light (i.e., PUVA) substantially increases the risk of cutaneous squamous cell cancer, but not of basal cell cancer, within a decade of beginning treatment. To assess the persistence of cancer risk among individuals treated with PUVA, including those who discontinued therapy long ago and those without substantial exposure to other carcinogens, we prospectively studied a cohort of 1380 patients with psoriasis who were first treated during the period from January 1, 1975, through October 1, 1976, and evaluated risk factors associated with the development of cutaneous squamous cell cancers and basal cell cancers after 1985.Results: From 1975 through 1996, 237 patients developed 1422 cutaneous squamous cell cancers. From 1986 through 1996, 135 (12.5%) of 1081 patients without a prior squamous cell cancer developed 593 such tumors. From 1975 through 1997, 247 patients developed 1042 basal cell cancers; these patients included 151 individuals with a first basal cell cancer after 1985. Among those without a squamous cell or a basal cell cancer in the first decade of the prospective study, a strong dose-related increase in the risk of squamous cell cancer was observed in the subsequent decade (adjusted relative risk [> or =337 treatments versus <100 treatments] = 8.6; 95% confidence interval = 4.9-15.2). Risk of basal cell cancer was substantially increased only in those patients exposed to very high levels of PUVA (> or =337 treatments).Conclusions: High-dose exposure to PUVA is associated with a persistent, dose-related increase in the risk of squamous cell cancer, even among patients lacking substantial exposure to other carcinogens and among patients without substantial recent exposure to PUVA. Exposure to PUVA has far less effect on the risk of basal cell cancer. The use of PUVA for psoriasis should be weighed against the increased cancer risk. [ABSTRACT FROM AUTHOR]

We report the results of a geochemical and isotopic study of mostly basaltic glasses recovered from 25 dredge stations along the northernmost 500 km of the Mariana Trough extension axis. The distribution of samples links regions of seafloor spreading to the south with regions farther north where a progression of rifting styles accompanies the earliest stages of back-arc basin extension. Petrographic, chemical and isotopic compositions of igneous rocks reflect the changing styles of extension, with typical back-arc basin basalts in the south which become increasingly similar to arc lavas to the north. Felsic lavas also appear along the extensional axis in the north. Glassy, sparsely phyric basalts characterize regions of seafloor spreading. Felsic lavas and porphyritic basalts occur in the northern, rifting portion. Geochemical and isotopic compositions distinguish between mature arc portions (Ce/Pb <10, Ba/La >20; 206Pb/204Pb >18.5, 87Sr/86Sr >0.7032, εNd< +8) and regions of back-arc spreading (Ce/Pb >10, Ba/La <20 206Pb/204Pb <18.9, 87Sr/86Sr <0.7032, εNd> +7). Samples from along the extensional axis of the northern Mariana Trough show progressive changes in chemical and isotopic compositions, from back-arc basin basalts that formed by seafloor spreading northward through increasingly arc–like basalts, until lavas that are indistinguishable from arc lavas are encountered in the northernmost portion of the rift. Batch-melting models indicate that northernmost rift lavas reflect higher degrees of melting, with 13 ± 5% melting where seafloor spreading occurs, doubling to 28 ± 8% for the northernmost part of the rift axis. The greater degree of melting in the north reflects the greater amount of water added to the mantle source, reflecting the arc-like nature of the source region and melt generation style characteristic of the initial stages of back-arc basin formation. Our data indicate that F = 0.44W + 0.07, where F is the degree of mantle melting and W is the percent water in the mantle. ‘True’ back-arc basin basalts are generated by adiabatic decompression associated with mantle upwelling in mature extensional settings. Eruption of ‘true’ back-arc basin basalts accompanies seafloor spreading, which begins when the basin is 100–150 km wide. The arc is disrupted during early rift formation, because arc magmatism is captured by the extension axis, but the generation of arc melts by hydrous melting of the mantle wedge continues whether or not back-arc extension is occurring. Back-arc basin seafloor spreading requires development of an upwelling mantle flow regime, allowing melting by adiabatic decompression, similar to that responsible for mid-ocean ridge basalt (MORB). The arc begins to re-form once extension progresses nearly to the point of seafloor spreading. [ABSTRACT FROM AUTHOR]

After drawing a distinction between internal and external labor market analysis, patterns in the sex structure of employment markets in nursing, social work, librarianship, and school teaching are examined. Findings indicate that the relative number of men employed in these "female" fields has increased and that males are disproportionately represented in the administrative components of the "female" semiprofessions. The role which internal labor market structures play in determining the continuance of boundaries to "male" and "female" work is discussed. [ABSTRACT FROM AUTHOR]

Over the past decade the United States has increasingly turned its attention toward regional trade liberalisation, beginning first with the US-Israel reciprocal tariff agreement of 1984, followed by the Canada-US Free Trade Agreement (CAFTA), and now negotiations with Mexico to form a trilateral North American Free Trade Area (NAFTA). The reasons for the US policy shift are not entirely clear, though some possibilities include US frustration with the slow progress in the GATT, a desire to improve access for US trade and investment in the markets of two of its largest trade partners and, in the case of Mexico, to enhance the competitive position of the United States through association with a low-cost supplier. Its interest in Mexico in particular also stems from a desire to strengthen democratic institutions along its borders, control illegal immigration, and facilitate drug interdiction. [ABSTRACT FROM AUTHOR]

Clinical isolates pf Pseudomonas aeruginosa from patients with cystic fibrosis were studied in an effort to determine the unique characteristics of the infecting strains and to elucidate the pattern of colonization. Of 413 patients studied, 81% were chronically infected with P. aeruginosa. Patients from whom P. aeruginosa was never or only occasionally isolated were in better clinical condition than the chronically infected patients. Isolates were classified into six morphologic varieties: classic, rough, mucoid, gelatinous, dwarf, and enterobacter. Most patients had two or more of these varieties. Such multiple varieties from the same individual were of the same serotype but often differed in antibiotic susceptibility as determined by both the disk and the minimal inhibitory concentration methods. These differences were apparent when mucoid strains were compared with nonmucoid strains and when nonmucoid strains were compared with one another. Studies of antibiotic susceptibility should be performed on each morphologically different type of P. aeruginosa obtained from patients with cystic fibrosis. [ABSTRACT FROM PUBLISHER]

Most patients with cystic fibrosis (CF) develop chronic endobronchial infection with mucoid Pseudomonas aeruginosa. It has been suggested that opsonic antibodies to the mucoid exopolysaccharide of P. aeruginosa protect older CF patients (>12 years of age) who have remained free of colonization by this organism. Serum antibodies from chronically infected CF patients had greater total complement-dependent opsonic activity than did those of older noncolonized patients (P < .02), but when bound antibody was equalized, opsonic quality was greater for the latter group (P < .03). In longitudinal studies, antibody titers to mucoid P. aeruginosa rose greatly after initial infection, but opsonic quality declined (P = .002). Twenty CF patients who passed age 12 free of P. aeruginosa colonization developed chronic P. aeruginosa lung infection at ages 14–35 years. Thus, naturally occurring antibodies do not protect CF patients from P. aeruginosa infection, and opsonic quality of serum antibodies deteriorates as infection becomes established. [ABSTRACT FROM PUBLISHER]

IgG antibody to the outer membrane of Pseudomonas cepacia was quantified in sera from controls without cystic fibrosis (CF) and from Pseudomonas aeruginosa- and P. cepacia-infected and noninfected patients with CF. The mean antibody titer in the P. cepacia-infected group was significantly higher than that in the other three groups; the mean titer in the P. aeruginosa-infected group was significantly higher than that in the noninfected and control groups. Preabsorption of CF sera with P. cepacia outer membrane produced a significantly lowermean antibody concentration than did matched samples preabsorbed with an equal amount of lipopolysaccharide. By western blot, significantly more P. cepacia-infected patients produced IgG to the 27- than the 36-kilodalton (kDa) porin protein of P. cepacia; 12 of 16 P. aeruginosa-infected patients produced IgG to the 27-kDa porin. Sera from all patients in both groups contained IgG to the porin protein of P. aeruginosa by western blot. We conclude that the 27-kDa porin of P. cepacia is antigenic in most P. cepacia-infected patients with CF and that some P. cepacia outer membrane components may be antigenically related to those of P. aeruginosa. [ABSTRACT FROM PUBLISHER]

Under fasting conditions, the dopamine (DA) metabolite homovanillic acid (HVA) in plasma originates mainly from central DA neurons or from central and peripheral noradrenergic (NA) neurons. The latter source contributes, in addition to HVA, the norepinephrine metabolites, for example, 3-methoxy-4-hydroxyphenylglycol (MHPG). It has been shown in primates that the association between HVA and MHPG in plasma or urine under varying rates of NA metabolism can be used to obtain an estimate of the central DA neuronal contribution of HVA to plasma or urine. This estimate is called the central dopaminergic index (CDI). Two studies presented here examine the applicability of this model in schizophrenia patients. The results were consistent with the proposed model and suggested that only about 30 percent of the total plasma HVA concentrations in our patients were derived from central DA neurons. A convenient modification of this model is proposed for future studies. Since the CDI of plasma HVA is not likely to be confounded by NA activity, this tool may prove useful in disentangling the roles played by the DA and NA systems in schizophrenia. [ABSTRACT FROM PUBLISHER]

The article reviews the analysis of the problem and the development insurance proposals which are contained in the report International Compensation for Fluctuations in Commodity Trade. The Committee of Experts which prepared the report was faced, basically, with the need to find a balance between measures to promote greater stability in primary producing countries and measures to provide these countries with more nearly continuous and larger supplies of resources for development. The Committee's proposals can best be characterised as a form of social insurance for the steadier development of primary producing countries. A development insurance fund is to be established on the basis of contributions by member countries, with the idea that the primary producers will draw out more than they contribute and the advanced economies less than they contribute. Both plans envisage covering export proceeds in the sense of merchandise exports. The base for measuring shortfalls has already been indicated as relative to a moving average of the proceeds of the preceding three, or four, years. All measurements and compensation are to be in real terms. There is to be an initial disallowance to avoid minor claims, and only partial compensation beyond the minimum deduction is to be made.

Discusses the role of the identity theory of truth. Definitions of the identity theory of truth; Propositional truth and material truth; The identity theory of truth as a theory of propositional truth; Hegel's interest in material truth; Conception of truth.

The use of gentamicin was studied in 80 patients with cystic fibrosis complicated by severe chronic pulmonary infection due to Pseudomonas. Gentamicin was administered intramuscularly or intravenously in a dose of 7 mg/kg per 24 hr not exceeding a total daily dose of 180 mg. In some cases, 16–20 mg four times a day was administered by aerosol. Clinical, bacteriologic, hematologic, renal, hepatic, and pulmonary evaluations were carried out. Gentamicin was well tolerated and appears to be a relatively nontoxic drug when used at this dose. It was clinically effective in controlling severe pseudomonas pulmonary infection in patients with cystic fibrosis. [ABSTRACT FROM PUBLISHER]