bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethnic differences in the clinical and laboratory associations with retinopathy in adult onset diabetes: studies in patients of African, European and Indian origins
Authors: KALK W. J. , JOANNOU J. , NTSEPO S. , MAHOMED I. , MAHANLAL P. , BECKER P. J. 
Published: November 2003

Objective. To evaluate the prevalence of diabetic retinopathy (DR) and its associations in adult onset diabetic patients of African, European and Indian origins. Design. The prevalence of retinopathy was determined by 60° retinal photography in 507 consecutive out‐patients. Clinical and laboratory associations were evaluated. Setting. Diabetes clinic in a large community hospital. Main outcome measures. The associations between clinical and laboratory measurements with retinopathy. Results. African patients (A) had shorter duration of diabetes (P < 0.001), higher HbA1 levels (P < 0.01) compared to those of Europeans (E) and Indian (I) extraction. A also had lower C‐peptide levels (median 0.57 nmol L−1; vs. E, 0.81 nmol L−1 and I, 0.93 nmol L−1) (P < 0.001). The prevalences of retinopathy at diagnosis (21–25%) and overall were similar (A 37%, E 41%, I 37%). Severe DR was more frequent in the Africans (52%, P < 0.0001) and Indians (41%, P = 0.03) compared to the Europeans (26%). In Africans DR was significantly associated only with duration of diabetes (P < 0.0001) and macro‐albuminuria (P = 0.01); in I it was also associated with systolic BP (P = 0.03); in E also with lower C‐peptide levels (P = 0.0002), worse glycaemic control and greater use of insulin (P < 0.0001). In patients with DR insulin was used less frequently in A (35%) than in E patients (62%) (P = 0.001). Conclusions. In South Africa, the African population with adult onset diabetes has the highest prevalence of severe retinopathy, probably the result of very poor glycaemic control attributable to more severe insulinopenia and infrequent insulin treatment. Visual loss from diabetic retinopathy is likely to be considerable in Africans.
Moderate beer consumption and the blood coagulation in patients with coronary artery disease
Authors: GORINSTEIN S. , ZEMSER M. , LICHMAN I. , BEREBI A. , KLEIPFISH A. , LIBMAN I. , TRAKHTENBERG S. , CASPI A. 
Published: November 2003

Objectives. To evaluate the influence of a short period of moderate beer consumption on the status of the thrombolitic activity in patients with coronary artery disease (CAD). Subjects and design. From 28 patients with two‐ or three‐vessel CAD 22 were randomly assigned to an experimental group (EG) and six to control group (CG). Before and after completion of the study every one of the 28 patients was examined and a wide range of laboratory tests was performed. Setting. A University Hospital in Israel. Intervention. Of the EG, 22 patients consumed 330 mL of beer day−1 (20 g of alcohol) for the 30‐day period in addition to the usual antiatherosclerotic diet. Patients of the CG did not consume alcohol beverages. Main outcome measures. Fibrinogen, prothrombin time (PT), coagulant activity of Factor VII (F VIIc) and Factor VII antigen (F VIIag), and plasminogen activator inhibitor (PAI) levels were studied. Results. After the investigation a statistically significant decrease was found in F VIIc (P < 0.01) and F VIIag (P < 0.001) and to a lesser extent a decrease in the value of PAI. Fibrinogen and PT remained unchanged in the EG also. Conclusions. Even a short period of moderate beer consumption results in a decrease in thrombogenic activity. The only sensitive tests were F VIIc and F VIIag. The decrease in thrombogenic activity may be the main cause of decreased mortality in patients with CAD who consume moderate quantities of alcoholic beverages.
Hydrogen incorporation in Ti‐based metal–matrix composites fabricated by vacuum plasma spraying and vacuum hot pressing
Authors: LI J. H. , GRANT P. S. , JENKINS M. L. , CANTOR B. 
Published: November 2003

In this paper we investigate the incorporation of hydrogen as a temporary alloying element during vacuum plasma spraying (VPS) of Ti‐based metal–matrix composites and show that it has probable beneficial effects for secondary processing by vacuum hot pressing (VHP).The composites investigated included both commercial purity Ti and Ti–6Al–4V matrices, which were sprayed onto DRA Sigma SiC fibres. The as‐sprayed matrix microstructures were investigated by transmission electron microscopy and X‐ray diffractometry, and were found to consist in both cases of a fine mixture of (1) hexagonal α′‐Ti martensite plates, with an increased lattice parameter relative to the usual value, presumably due to dissolved hydrogen; and (2) an increased proportion of equiaxed b.c.c. β grains, probably stabilized by dissolved hydrogen. Both phases, but particularlyβ, contained needle‐shaped b.c.t. hydride precipitates.It has been found that monotapes produced by VHP can be consolidated more easily by secondary VHP than those produced by electric arc spraying, leading to reduced adverse interfacial reactions between fibre and matrix. This improved processability is believed to be due to the combination of a greater proportion of the more ductile β phase and the very small grain sizes inherent in VPS. However, the dissolved hydrogen and the potentially embrittling hydride precipitates are removed during VHP. The presence of hydrogen after primary VPS may therefore have an overall beneficial effect.
Morphological studies of Cu(I)‐complexed bipyridine‐containing block copolymers by combined transmission electron microscopy techniques
Authors: Göldel A. , Schubert U. S. , Eisenbach C. D. 
Published: November 2003

The design of molecular species which can form well‐defined macromolecular architectures by spontaneous, recognition‐directed self‐assembly of their components is a major goal in supramolecular chemistry. We synthesized block copolymers with polyether and bipyridine or oligo‐(bipyridine) containing segments where the latter could form double‐helical structures by metal complexation. Upon complexation with Cu(I) these systems showed a dramatic change in the thermal and mechanical properties from a waxy system to a thermoplastic elastomeric behaviour. This effect could be explained by the formation of a multiphase polymer system consisting of domains of bipyridine or oligo(bipyridine) Cu(I) complexes in a matrix of amorphous soft segments.In the solution‐cast films both nitrogen and copper could be detected with electron energy‐loss spectroscopy. Element spectroscopic imaging pictures of the net nitrogen and copper element distribution were identical and revealed a microphase‐separated system with identical morphological structures. High‐resolution bright‐field images revealed fine structures (interference lines) which were in accordance with stacks of [Cu(I)(bpy)2] complexes. Electron diffraction patterns showed that the supramolecular order could be perfected through annealing.
The optical rotator
Authors: Tandrup T. , Gundersen H. J. G. , Vedel Jensen E. B. 
Published: November 2003

The optical rotator is an unbiased, local stereological principle for estimation of cell volume and cell surface area in thick, transparent slabs. The underlying principle was first described in 1993 by Kiêu &38; Jensen ( J. Microsc170, 45–51) who also derived an estimator of length. In this study we further discuss the methods derived from this principle and present two new local volume estimators.The optical rotator benefits from information obtained in all three dimensions in thick sections but avoids over‐/underprojection problems at the extremes of the cell. Using computer‐assisted microscopes the extra measurements demand minimal extra effort and make this estimator even more efficient when it comes to estimation of individual cell size than many of the previous local estimators. We demonstrate the principle of the optical rotator in an example (the cells in the dorsal root ganglion of the rat), evaluate its efficiency and compare it with other unbiased, local stereological principles available for estimation of cell volume and surface area.
X‐ray contact microscopy using an excimer laser plasma source with different target materials and laser pulse durations
Authors: ALBERTANO P. , REALE L. , PALLADINO L. , REALE A. , COTTON R. , BOLLANTI S. , DI LAZZARO P. , FLORA F. , LISI N. , NOTTOLA A. , VIGLI PAPADAKI K. , LETARDI T. , BANAI D. , CONTI A. , MORET M. , GRILLI A. 
Published: November 2003

Soft X‐ray contact microscopy (SXCM), using a pulsed X‐ray source, offers the possibility of imaging the ultrastructure of living biological systems at sub‐100 nm resolution. We have developed a table‐top pulsed plasma X‐ray source for this application, generated by a large‐volume XeCl laser, achieving a good conversion efficiency to ‘water‐window’ X‐rays (hν≈280–530 eV).Optimum plasma conditions for SXCM are discussed, including the effect of pulse duration, target material and resist development time on image resolution. Soft X‐ray contact images of Chlamydomonas dysosmos (unicellular alga) and of the cyanobacterium Leptolyngbya are shown.
Estimation of the connectivity of a synthetic porous medium
Authors: Roberts N. , Reed M. , Nesbitt G. 
Published: November 2003

Highly connected continuous phases in a porous medium can usefully be described in terms of their connectivity. Appropriate descriptions of connectivity are the connectivity number density or the related quantity Euler number density. Broadly speaking, Euler number density is equal to the number of discrete objects which comprise the phase plus the number of enclosed cavities within those objects less the number of tunnels through the objects, per unit volume. The conneulor is a convenient stereological method for estimating Euler number density. The relevant probes (i.e. disectors) from which the estimate is obtained are randomly positioned and arbitrary orientated pairs of closely spaced parallel planes.We have applied the conneulor method to estimate the Euler number density of the pore space in a cell of sintered silica imaged using a magnetic resonance (MR) microscope. By flooding the cell simultaneously with a mixture of oil and water prior to imaging we were able to obtain a series of 16 contiguous perfectly registered serial MR sections depicting the pore space. The Euler number density of the porous medium estimated from four systematic pairs of consecutive MR images is −5.6 per mm3 with a coefficient of error (CE) of 10–15%. The Euler number density was lower near the walls of the silica cell than the centre, which is consistent with the method of formation of the cell.In contrast to the majority of stereological methods, and in common with the physical disector, the conneulor method requires that deductions are made regarding the changes in the morphology of the structure of interest that occur between the two parallel image planes comprising the sampling probe. We therefore compared estimates of the Euler number density of the pore space obtained by two independent observers. We conclude that careful thought and discussion between observers is required before a definitive set of counts is made. Once mastered the conneulor counting rules are straightforward to apply.
Evidence for Multiple Opioid Receptors in the Human Posterior Pituitary
Authors: Jordan D. , Tafani J. A. M. , Ries C. , Zajac J. M. , Simonnet G. , Martin D. , Kopp N. , Allard M. 
Published: November 2003

The distribution and quantification of opioid receptor types in post‐mortem human pituitary cryostat sections was determined by quantitative in vitro receptor autoradiography. Highly specific radioligands were used for each opioid receptor type, i.e. [125I]‐FK‐33‐824 for μ‐opioid sites, [125I][D.Ala2]‐Deltorphin‐I for δ‐opioid sites and 3H‐U69,593 for κ‐opioid sites.None of the five specimens tested exhibited any labelling in the anterior lobe of the pituitary for the three radioligands. As for the posterior pituitary, all 5 specimens contained both μ and κ‐opioid binding sites whereas none of them showed δ‐binding sites.The presence of both μ‐ and κ‐opioid binding sites in the human posterior pituitary contrasts with previous findings in the rat where only κ‐sites have been found. The present study could contribute to understanding of the functional action of opioids in the human pituitary.
Absolute serum hormone levels predict the magnitude of change in anterior knee laxity across the menstrual cycle
Authors: Shultz Sandra J. , Gansneder Bruce M. , Sander Todd C. , Kirk Susan E. , Perrin David H. 
Published: November 2003

AbstractThis study aimed to determine whether absolute sex hormone concentrations predict the magnitude of knee joint laxity changes across the menstrual cycle. Twenty‐two females (18–30 years, body mass index ≤30), who reported normal menstrual cycles for the previous 6 months were tested daily across one complete menstrual cycle for serum levels of estradiol (E = pg/mL), progesterone (P = ng/mL), and testosterone (T = ng/dL), and knee joint laxity (KLax = mm displacement at 134N) measured with a standard knee arthrometer. The change in KLax across the cycle (maximum–minimum), and minimum (early follicular) and peak (postovulatory) hormone concentrations were recorded for each subject. A stepwise linear regression determined if the minimum, peak, or absolute change in hormone concentrations would predict the magnitude of change in KLax across the cycle. KLax changed on average 3.2 ± 1.1 mm across the menstrual cycle (range, 1.5–5.3 mm). Minimum levels of E (39.9 ± 11.8 pg/mL) and P (0.61 ± 0.27 ng/mL), coupled with peak concentrations of E (199.6 ± 54.9 pg/mL) and T (22.5 ± 10.5 ng/dL) explained 57.6% of the change in KLax across the cycle. Greater absolute changes in KLax were observed in response to peak E and T levels when minimum E concentrations were lower and minimum P concentrations were higher in the early follicular phase. The absolute minimum concentrations of E and P in the early follicular phase appear to be important factors in determining the sensitivity of the knee joint's response to changing hormone levels. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Pharmacokinetics of penicillin‐G in ewes and cows in late pregnancy and in early lactation
Authors: Bengtsson B. , Jacobsson S‐o. , Luthman J. , Franklin A. 
Published: November 2003

Concentrations of penicillin‐G in serum were determined after single intravenous doses of potassium penicillin‐G (10 mg/kg body wt) to ewes and cows in late pregnancy and in early lactation. Penicillin‐G in serum was analysed by a microbiological method and pharmacokinetic parameters were calculated by model‐independent methods. Serum concentrations were lower in early lactation than in late pregnancy in both ewes and cows. The differences were statistically significant at most sampling times in ewes but only during the first hour in cows.Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination‐half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin‐G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug.
Furosemide‐induced changes in plasma and blood volume of camels (Camelus dromedarius)
Authors: ALI B.H. , ALHADRAMI G.A. , BASHIR A.K. 
Published: November 2003

This work examines the effect of treatment of camels with furosemide (1 or 2 mg/kg, intravenously) on blood volume (BV), plasma volume (PV) and the plasma concentrations of total solids (PTS), plasma total protein (PTP) haemaglobin (Hb) and haematocrit (PCV). The cumulative urine produced during the 4 h following furosemide administration (2 mg/kg) averaged 22.2 mL/kg, compared to 2.3 mL/kg in controls. None of the above parameters were significantly changed by furosemide treatment at either dose.In another experiment, the effect of the two doses of furosemide on the sequential changes on some of the above parameters was investigated at 5, 10, 15, 30, 45, 60, 75, 90, 105, 120 and 240 min after the drug administration.On the whole, there were no significant changes in any of the measured parameters, except for small but statistically significant increases in the PCV and Hb at 30 and 45 min post treatment.It is concluded that, despite the marked diuresis following furosemide administration, the camel appears to be able to maintain its bodily fluid haemostasis.
Testing models of female reproductive migratory behaviour and population structure in the Caribbean hawksbill turtle, Eretmochelys imbricata, with mtDNA sequences
Authors: BASS A. L. , GOOD D. A. , BJORNDAL K. A. , RICHARDSON J. I. , HILLIS Z.‐M. , HORROCKS J. A. , BOWEN B. W. 
Published: November 2003

AbstractInformation on the reproductive behaviour and population structure of female hawksbill turtles, Eretmochelys imbricata, is necessary to define conservation priorities for this highly endangered species. Two hypotheses to explain female nest site choice, natal homing and social facilitation, were tested by analysing mtDNA control region sequences of 103 individuals from seven nesting colonies in the Caribbean and western Atlantic. Under the social facilitation model, newly mature females follow older females to a nesting location, and subsequently use this site for future nesting. This model generates an expectation that female lineages will be homogenized among regional nesting colonies. Contrary to expectations of the social facilitation model, mtDNA lineages were highly structured among western Atlantic nesting colonies. These analyses identified at least 6 female breeding stocks in the Caribbean and western Atlantic and support a natal homing model for recruitment of breeding females. Reproductive populations are effectively isolated over ecological time scales, and recovery plans for this species should include protection at the level of individual nesting colonies.
Migration and evolution of lesser long‐nosed bats Leptonycteris curasoae, inferred from mitochondrial DNA
Authors: WILKINSON G. S. , FLEMING T. H. 
Published: November 2003

AbstractWe used sequence variation within 297 bp of control region mitochondrial DNA (mtDNA) amplified from 53 lesser long‐nosed bats, Leptonycteris curasoae (Phyllostomidae: Glossophaginae) captured at 13 locations in south‐western United States and Mexico and one site in Venezuela to infer population structure and possible migration routes of this endangered nectar‐ and fruit‐eating species. Phylogenetic analysis using maximum parsimony and UPGMA confirmed species and subspecies distinctions within Leptonycteris and revealed two clades exhibiting 3% sequence divergence within the Mexican subspecies, L. c. yerbabuenae. Even though many roosts contained L. c. yerbabuenae from both clades, weak population structure was detected both by a correlation between genetic differentiation, Fstr and geographical distance and by a cladistic estimate of the number of migration events required to align bat sequences with geographical location on maximum parsimony, as compared to random, trees. Three results suggest that L. c. yerbabuenae are more likely to migrate between sites along the Pacific coast of Mexico or along the foothills of the Sierra Madre Occidental than between these regions. (1) Seventeen of 20 bats which shared an identical sequence were captured up to 1800 km apart but within the same putative migration corridor. (2) Residuals from a regression of Fst on distance were greater between than within these regions. (3) Fewer migration events were required to align bats with these two groups than expected from random assignment. We recommend analysing independent genetic data and monitoring bat visitation to roost sites during migration to confirm these postulated movements.
Distinguishing between primary and secondary intergradation among morphologically differentiated populations of Anolis marmoratus
Authors: SCHNEIDER C. J. 
Published: November 2003

AbstractDistinguishing between primary and secondary intergradation among differentiated populations, and the relative importance of drift and selection, are persistent problems in evolutionary biology. An historical perspective on population interactions can provide insight into the nature of contacts, and thus help resolve these questions. Continuously distributed populations of Anolis marmoratus from the island of Basse Terre in the Guadeloupean archipelago of the Lesser Antilles show a striking degree of geographic variation in morphology. Initial surveys of mtDNA variation from throughout the Guadeloupean Archipelago revealed one case where levels of sequence difference and phylogenetic relationships of alleles from morphologically differentiated populations from the east coast of Basse Terre were consistent with primary intergradation. In this paper, I examine the genetic population structure of a series of populations spanning this north‐south cline in morphological variation to test the hypothesis of primary intergradation. Sequences of the mitochondrial cytochrome‐b gene from 50 individuals representing five populations spanning the cline were obtained and fourteen unique haplotypes (differing by 2% or less) were detected. Patterns of nucleotide substitution among haplotypes do not deviate from neutral expectation indicating no effect of selection at the level of mtDNA sequences. Estimates of population structure and gene flow were made using both summary statistics for nucleotide diversity (Nat) and cladistic methods. The results are sensitive to the choice of gene flow model, and this is discussed in detail. Mitochondrial variation in the northern populations may not be at equilibrium, and the phylogeny of alleles is consistent with a recent increase in effective population size. Estimates of nucleotide diversity, gene flow, and the phylogenetic relationships of haplotypes indicate that the southern‐most population (representing the extreme of morphological variation along this cline) has been relatively isolated from populations to the north and has experienced a reduced effective population size. The apparent clinal variation between the southern population and the others may therefore reflect secondary contact and introgression rather than primary intergradation.
Genotypic diversity revealed by allozymes and oligonucleotide DNA fingerprinting in French populations of the aquatic macrophyte Sparganium erectum
Authors: PIQUOT Y. , SAUMITOU‐LAPRADE P. , PETIT D. , VERNET P. , EPPLEN J. T. 
Published: November 2003

AbstractThe vast majority of perennial plants reproduce sexually and vegetatively at the same time. This may lead to important variation among clonal plant populations in their amount of genotypic diversity. In order to verify this assumption, we compare the clonal diversity of 10 natural populations of the aquatic clonal macrophyte Sparganium erectum in France. Diversity was quantified by DNA fingerprinting and allozyme electrophoresis for a sample of 10 shoots per population. Two DNA probes (CA)3 and (TAA)6TA, were selected among 10 synthetic oligonucleotide probes containing simple repeat motifs. Both allozymes and DNA fingerprints revealed different amounts of diversity among populations. Five populations consist of a single genotype, whereas two populations were genetically highly diverse. In four of the monomorphic populations, absence of fingerprints diversity was combined with uniformly heterozygous allozyme loci, suggesting that each population was composed of a single clone. In the highly diverse populations, the level of clonal diversity combined with the allele segregation of the two allozyme loci Lap and Est suggests frequent seedling recruitment. The origin of new genotypes remains unclear but the absence of widespread genotypes together with the discrete distribution of Sparganium erectum populations implies that new genotypes are locally produced through sexual reproduction.