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At least 973 records · Page 54Linked to original sources
PubMed2001

Identification of a novel single-nucleotide polymorphism (Val554Ile) and definition of eight common alleles for human IL4RA exon 11.

The interleukin (IL)-4 receptor alpha chain gene (IL4RA) is a polymorphic gene which is reportedly involved in the development of atopy. Of the 14 single-nucleotide polymorphisms (SNP) reported to date in the coding region of IL4RA, 11 are positioned to exon 11. This big exon encodes more than two thirds of the mature protein, including most of the cytoplasmic region. Here we report the identification of a new IL4RA SNP at the first nucleotide of codon 554 (GTA --> ATA) in exon 11, leading to an amino acid substitution from Val to Ile (V554I). Furthermore, we present complete nucleotide sequence data for eight common alleles resulting from combinations of 9 out of the 12 SNP at IL4RA exon 11. Homo- or heterozygous combinations of these eight alleles accounted for all the IL4RA exon 11 genotypes found in Caucasian individuals from our geographical area.

Alleles↗
PubMed1990

Endothelin receptors in human placenta: relationship to vascular resistance and thromboxane release.

This investigation was performed to study the potential role of endothelin in the modulation of fetoplacental vascular resistance in the human placenta. Full-term placentas from uncomplicated pregnancies were studied within 30 min of delivery. The umbilical artery and vein to a single placental cotyledon were cannulated and the artery perfused with RPMI media (0.82 ml/min). Endothelin 1 caused a sustained dose-dependent increase in perfusion pressure. Infused endothelin 1 (50 nM) stimulated thromboxane release 2.3-fold compared with basal values. Thromboxane release persisted for 15 min after discontinuation of endothelin. Properties of human placental endothelin 1 receptors were defined in binding studies performed on a crude membrane fraction of placental cotyledons. Binding was saturable, reached steady state by 3 h at 25 degrees C, and was linear with protein concentration. Scatchard analysis of binding data indicated a single class of high-affinity binding sites with a Kd of 36.1 +/- 9.7 pM and a density of 185.4 +/- 9.6 fmol/mg protein (n = 5). The potency order for competitive inhibition of the binding of 125I-labeled endothelin 1 was endothelin 1 greater than endothelin 2 = endothelin 3 = sarafotoxin S6b greater than big endothelin (human) = big endothelin (porcine). Phenylephrine, bradykinin, norepinephrine, atrial natriuretic factor, diltiazem, U46619, and angiotensin II did not displace 125I-endothelin 1 from its receptors. These experiments demonstrate that endothelin 1 is a potent pressor substance in the human fetoplacental cotyledon. Pressor effects of endothelin may be mediated by a combination of direct effects and stimulation of vasoconstrictor prostanoids.

Binding, Competitive↗
PubMed1985

When was a "negative" clinical trial big enough? How many patients you needed depends on what you found.

"Negative" clinical trials that conclude that neither of the treatments is superior are often criticized for having enrolled too few patients. These criticisms usually are based on formal sample size calculations that compute the numbers of patients required prospectively, as if the trial had not yet been carried out. We suggest that this "prospective" sample size calculation is incorrect, for once the trial is over we have "hard" data from which to estimate the actual size of the treatment effect. We can either generate confidence limits around the observed treatment effect or retrospectively compare it with the effect hypothesized before the trial. If the observed effect is small, the risk of the false-negative conclusion (and the sample size required to draw negative or equivalency conclusions) is often much less than that generated by the "prospective" calculation.

Clinical Trials as Topic↗
PubMed1989

In vitro and in vivo activity of chymotrypsin-activated big endothelin (porcine 1-40).

We investigated whether big endothelin (porcine 1-40) had contractile activity in isolated rat aorta or pressor activity when injected intravenously into the anesthetized rat. When isolated rat aorta was exposed to a 100 nM concentration of big endothelin, 4.8% of a maximal KCl contraction was observed, compared to 131% of KClmax when paired aortic rings were exposed to an equivalent concentration of synthetic endothelin. Likewise, big endothelin had very weak pressor activity when injected intravenously into anesthetized, ganglion-blocked rats at 10 nmol/kg. When big endothelin was incubated with chymotrypsin, native endothelin and other peptide fragments were formed. Chymotrypsin-treated big endothelin produced an endothelin-like contraction when applied to isolated rat aortic rings, and a characteristic endothelin-like effect on blood pressure in vivo. Our results indicate that the biological activity of endothelin could be effectively blocked by inhibiting the enzyme which converts big endothelin to endothelin.

Amino Acid Sequence↗
PubMed1995

Effects of metalloprotease inhibitors on smooth muscle endothelin-converting enzyme activity.

The enzyme responsible for the conversion of exogenous big endothelin-1 to endothelin-1 by porcine coronary arterial smooth muscle has been shown to be a metalloprotease. The potencies of eight metalloprotease inhibitors for this endothelin-converting enzyme were determined. CGS 25015, CGS 26129, and thiorphan inhibited the enzyme activity monophasically with IC50 values of 2.6, 2.4, and 190 microM, respectively. In contrast, the data obtained using phosphoramidon as an inhibitor were best fit by a two-site model. The biphasic concentration-response curve had IC50 values of 4.6 microM and 2.2 mM. Three analogs of phosphoramidon were also tested for enzyme inhibition. Removal of the rhamnose moiety of phosphoramidon reduced the potency (IC50 = 15 microM), whereas substitution of the rhamnose by N-[2-(2-naphthyl)ethyl] improved the potency (IC50 = 2.0 microM). These results identify a thiol and a phosphonyl series of compounds as smooth muscle endothelin-converting enzyme inhibitors. The structure-activity relationships revealed that an aromatic or aliphatic group in the P2' position or an aromatic group in the P1 position of the inhibitor significantly increased the potency.

Animals↗
PubMed1991

Importance of the C-terminal region of big endothelin-1 for specific conversion by phosphoramidon-sensitive endothelin converting enzyme.

Based on our previous findings that phosphoramidon-sensitive endothelin (ET) converting enzyme (ECE) converts human big ET-1 but does not big ET-3, we investigated structural requirement for substrate peptide. We prepared shorter peptides of big ET-1 and measured hydrolysis of the Trp-Val bond of these peptides. Relative hydrolysis ratios of big ET-1(1-38), (1-37), (16-37), (1-31) and (17-26) were 1, 1.15, 3.71, 0.01 and 0, respectively. In addition, big ET-2 and big ET-3 were not significantly converted by ECE. These results suggest that the carboxyl-terminal sequence at residues 32-37 of big ET-1 is important for conversion, whereas the amino-terminal disulfide loop structure appears to interfere with access of ECE to big ET-1.

Amino Acid Sequence↗
PubMed2001

[HLA-DRB1 gene polymorphism of Naxi ethnic group of Yunnan Province, China and its ethnological evolution analysis].

The HLA-DRB1 gene polymorphism of Naxi ethnic group of Yunnan Province, China was investigated for the first time using high resolution PCR-SBT method, which is based on sequences of HLA-DRB1 Intron 1 and Intron 2 with our improvement. From 60 individuals of Naxi 37 DRB1 alleles were detected. The distribution of allele frequencies is evenly spread for most of alleles detected in Naxi. However, the gene frequency for HLA-DRB1 * 12021 is 17.50%. The other common alleles (> 5%) were HLA-DRB1 * 1404(7.50%), 1504(5.83%), 04051(5.83%), 08032(5.83%), 09012(5%), 03011(5%), and they covered 35% of the total alleles detected from Naxi, and 52.49% after adding the frequency of HLA-DRB1 * 12021. HLA-DRB1 * 0305, 0438, 1123, 1132, 1310, 0812 were detected in Chinese for the first time, and were very rare in other ethnic groups worldwide. Using the HLA-DRB1 gene frequencies of various ethnic groups, we constructed the phylogenetic tree by Fitch-Margoliash and Least-Squares Distance Methods and Cavalli-Sforza's chord measure of genetic distance. In our dendrogram, the South China populations were clustered together, and Siberian, Japanese and Minority of North China were clustered together, in which two big clusters we thought represented the ancient Southern and Northern Mongolian. Our results showed Naxi was clustered with Lahu and Yao ethnic groups, which were in the cluster of South China population. Obviously Naxi belongs to the South China ethnic groups and can't trace its origin from northern ethnic groups with the HLA-DRB1 genetic data. But based on Naxi's historical folklore, it was down to Southern China from Northwest China. The preliminary analysis about its origin conundrum was discussed in this paper based on our genetic data in relationship with its history and ethnology studies.

China↗
PubMed1989

Alcohol-induced pancreatic injury (Part I). Unexplained features and ductular theories of pathogenesis.

The pathogenesis of alcoholic pancreatitis continues to be a puzzle. Classical theories of pathogenesis tend to overlook the dual nature of the disease, i.e., symptomatic acute attacks and chronic progressive parenchymal destruction. Furthermore, it is unknown why only a small minority of alcoholics develop clinical pancreatic injury. In addition, there is a lack of basic data concerning the natural history of the condition after cessation of alcohol consumption. The most widely accepted theory of pathogenesis postulates the deposition of protein plugs in peripheral pancreatic ducts as the initial lesion. However, it has not been established that these plugs are the cause rather than a result of pancreatic injury. The so-called "Big Duct" theories of pathogenesis (biliary-pancreatic reflux, duodeno-pancreatic reflux, and obstruction-hypersecretion) are confounded by a lack of agreement concerning the effect of alcohol on the sphincter of Oddi. Nutritional factors and heredity may be responsible for the selectivity of alcohol in this condition; in this regard, a number of dietary and HLA studies have been performed, but these have generally been inadequately controlled. Subcellular pancreatic injury (fat droplets, autophagic vacuoles, and mitochondrial lesions) has been observed in alcoholics without pancreatitis and in animals fed alcohol. In addition, ethanol feeding in animals has been shown to affect pancreatic cholesterol, phospholipid, and fatty acid metabolism as well as pancreatic content of digestive enzymes. Research is hampered by the lack of a suitable animal model of the disease.

Alcohol Drinking↗
PubMedDate not supplied

Experimental results with a whole body NMR-CT scanner using a resistive magnet.

A brief explanation is given on various advantageous features of NMR imaging methods for practical diagnostic purposes. A whole-body NMR-CT scanner utilizing a big resistive air-core magnet has been developed in cooperation with the Institute for Solid State Physics, University of Tokyo. This prototype NMR-CT scanner employs the projection-reconstruction-imaging method with a selective excitation technique for slicing. It can provide physicians with high quality proton NMR images within a practicable, acceptable short data-collection time. Typical NMR-CT images of healthy volunteers and patients were obtained in the experiments using this device, and are presented here. Although the images mainly reflect the hydrogen nucleus concentrations of the subjects, they are strongly affected by relaxation times T1 and T2 and also by the the subjects' internal and external bodily activities. The effects of various NMR parameters in the reconstructed images are analyzed and examples showing these parameter effects are demonstrated. Another advantage of NMR imaging shown here, is a sagittal image of a human body, which is difficult to obtain by using an X-ray CT scanner.

Abdomen↗
PubMed1999

Big decisions based on small numbers: lessons from BSE.

The epidemic of bovine spongiform encephalopathy (BSE) has been the most expensive disaster ever to have befallen farming in the UK. It is believed to have led to a new form of spongiform encephalopathy in humans and as yet there is no way of knowing how many people will die of this disease. In order to curtail the BSE epidemic major decisions had to be made, often on the basis of inadequate scientific data. These data may have been derived from experiments using small sample numbers. Here we review some examples of where this has happened, sometimes with a beneficial outcome and sometimes with a misleading outcome. The identification of BSE as a new disease depended on precise neuropathological observation of a small number of cases rather than the obvious occurrence of large numbers of sick animals. Similarly, the recognition that BSE may have led to disease in humans was based on the neuropathological and clinical picture of new variant Creutzfeldt-Jakob disease (CJD) rather than on an increase in the number of cases of CJD in the UK. Early in the BSE epidemic the possibility that disease could be maternally transmitted from cow to calf was raised, mainly because of a belief that such transmission occurs in scrapie disease of sheep. But, we argue, the evidence for maternal transmission of scrapie, collected in the 1960s, was based on small numbers and is inadequate. Subsequent research has shown a very substantial genetic component in scrapie and epidemiological data show no excess risk in the offspring of affected ewes relative to the risk in the offspring of affected rams. An experiment to determine whether maternal transmission occurs in BSE was flawed and was unable to distinguish between maternal transmission and genetic susceptibility to environmental contamination. An assessment of the risk of BSE to humans depends on determining the levels of infectivity in tissues and transmissibility across species. Data on both of these are deficient, so it is not possible to predict how many people in the UK or elsewhere will become affected with new variant CJD in the next fifty years. The assessment of whether BSE could be transmitted to sheep and whether sheep therefore pose a risk to humans is hampered by a serious lack of evidence about the epidemiology of scrapie in the UK and elsewhere. The UK has paid a heavy price for the BSE epidemic but lessons should be learned from the experience. Every country should have a Specified Offals Ban even if it has no cases of BSE because, by the time it has, it will be too late. Furthermore, the occasional case of BSE should not be regarded as insignificant since it may be the harbinger of an epidemic in the making.

Animals↗
PubMed1995

Detection of movements imposed on human hip, knee, ankle and toe joints.

1. The angular displacements necessary for 70% correct detection were determined in normal subjects at the hip, knee and ankle joints, and the interphalangeal joint of the big toe. Angular velocities between 0.1 and 50 deg s-1 were tested. The hip and knee joints were tested in slight flexion and the ankle and toe joints were tested in the mid-range of the normal excursion. The joints were carefully supported for testing and the muscles acting at the joints were relaxed. 2. When detection thresholds and velocities were assessed in terms of angular displacements and angular velocities, proprioceptive performances at the hip, knee and ankle joints were superior to that at the toe joint. 3. When detection levels and displacement velocities were expressed in terms of linear displacements and velocities at the tip of the extended toe for all four joints, instead of in angular terms, the ankle gave the best performance and the hip and knee the worst. 4. The detection level and velocity data were expressed also in terms of proportional changes in the fascicle lengths of muscles operating these joints. Analysis in these terms showed that performance was similar at the hip, knee and ankle joints, but that performance for the toe was much poorer than for the other joints. 5. These results for the hip, knee and ankle are similar to those previously measured for the elbow and distal interphlangeal joint of the finger, and are consistent with the theory that muscle fascicle length is the variable of significance to the central nervous system. However, the proprioceptive performance at the big toe is notably poorer than all other joints studied and analysed in terms of this variable.

Adult↗
PubMed2006

Determination of impact of urbanization on agricultural land and wetland land use in Balçovas' delta by remote sensing and GIS technique.

Because of their intense vegetation and the fact that they include areas of coastline, deltas situated in the vicinity of big cities are areas of greet attraction for people who wish to get away from in a crowded city. However, deltas, with their fertile soil and unique flora and fauna, need to be protected. In order for the use of such areas to be planned in a sustainable way by local authorities, there is a need for detailed data about these regions. In this study, the changes in land use of the Balçova Delta, which is to the immediate west of Turkey's third largest city Izmir, from 1957 up to the present day, were investigated. In the study, using aerial photographs taken in 1957, 1976 and 1995 and an IKONOS satellite image from the year 2005, the natural and cultural characteristics of the region and changes in the coastline were determined spatially. Through this study, which aimed to reveal the characteristics of the areas of land already lost as well as the types of land use in the Balçova delta and to determine geographically the remaining areas in need of protection, local authorities were provided with the required data support. Balçova consists of flat and fertile wetland with mainly citrus-fruit orchards and flower-producing green houses. The marsh and lagoon system situated in the coastal areas of the delta provides a habitat for wild life, in particular birds. In the Balçova Delta, which provides feeding and resting for migratory birds, freshwater sources are of vital importance for fauna and flora. The settlement area, which in 1957 was 182 ha, increased 11-fold up to the year 2005 when it reached 2,141 ha. On the other hand, great losses were determined in farming land, olive groves, forest and in the marsh and lagoon system. This unsystematic and rapid urbanization occurring in the study region is not only causing the loss of important agricultural land and wetland, but also lasting water and soil pollution.

Agriculture↗
PubMed2006

The E3 ubiquitin ligase BIG BROTHER controls arabidopsis organ size in a dosage-dependent manner.

Organ growth up to a species-specific size is tightly regulated in plants and animals. Final organ size is remarkably constant within a given species, suggesting that a species-specific size checkpoint terminates organ growth in a coordinated and timely manner. Phytohormones influence plant organ size, but their precise functions in size control are unclear because of their pleiotropic and complex developmental roles. The Arabidopsis transcription factors AINTEGUMENTA and JAGGED promote organ growth by maintaining cellular proliferation potential. Loss of the Antirrhinum transcription factor CINCINNATA causes leaf overgrowth, yet also leads to a highly abnormal leaf shape. Thus, no dedicated factor that limits the final size of plant organs has been isolated. Here, we identify the novel RING-finger protein BIG BROTHER (BB) as a repressor of plant organ growth. Small changes in BB expression levels substantially alter organ size, indicating a central regulatory role for BB in growth control. Recombinant BB protein has E3 ubiquitin-ligase activity that is essential for its in vivo function, suggesting that BB acts by marking cellular proteins for degradation. Our data indicate that plants limit the duration of organ growth and ultimately organ size by actively degrading critical growth stimulators.

Amino Acid Sequence↗
PubMed1997

Reliability and practicability of bacteriological monitoring of beef carcass contamination and their rating within a hygiene quality control programme of abattoirs.

A total of 9600 swab samples from 900 carcasses originating from ten different abattoirs were subjected to bacteriological examination. Two sampling sites, brisket and forearm, consistently showed the highest contamination rates. The following sites are recommended for sampling: on the lateral side of the carcass neck, forearm, shoulder, brisket and abdomen. The neck is recommended for the medial side. Compared to the large variance of contamination either on individual carcasses or between different carcasses, the differences in the variance of results between double swab and incision sampling techniques should be of minor importance. Considering this big variance of colony counts, it is suggested to take five to six swab samples from each of at least ten to 15 carcasses once a month. With a view to a more differentiated and evident evaluation the results should be recorded in a 'box plots' and not in the form of mean values and standard deviations. The data confirms bacteriological monitoring of beef carcasses as a useful tool for the verification of slaughter hygiene.

Animals↗
PubMed2000

Molecular epidemiology of a large classical swine fever epidemic in the European Union in 1997-1998.

A big epidemic of classical swine fever (CSF) occurred in the European Community in 1997. The first case was reported at the beginning of January 1997 from Germany. The disease presumably spread to the Netherlands, and from there to Italy, Spain and eventually to Belgium. About 30 isolates from these outbreaks were analysed by comparison of the nucleotide sequence data generated from fragments of both the E2 glycoprotein gene (190 nucleotides) and from the 5'-nontranslated region (5'-NTR; 150 nucleotides). By combining epidemiological data with genetic typing, it was found that the outbreaks were related and caused by a virus belonging to the genetic subgroup 2.1. As this type of virus had been reported infrequently in Europe and not at all since 1993, we postulate that it was newly introduced into the European Union (EU).

5' Untranslated Regions↗
PubMed1990

Root mass and vertical root distribution of five semi-arid plant species.

The root masses of big sagebrush, Great Basin wild rye, Russian thistle, streambank wheatgrass, and crested wheatgrass were determined at 20 cm depth increments from plants grown in high clay content soils in cylindrical containers. All species had roots in the deepest (100-120 cm) depth increment. Crested wheatgrass had the greatest average (+/- SD) total root mass (775 +/- 211 g). Results provide data for some scenarios for fate and effect models for shallow-land burial of low-level radioactive wastes in semi-arid environments.

Desert Climate↗
PubMed2004

New dark energy constraints from supernovae, microwave background, and galaxy clustering.

Using supernova, cosmic microwave background, and galaxy clustering data, we make the most accurate measurements to date of the dark energy density rho(X) as a function of cosmic time, constraining it in a rather model-independent way, assuming a flat universe. We find that Einstein's simplest scenario, where rho(X)(z) is constant, remains consistent with these new tight constraints and that a big crunch or big rip is more than 50 Gyr away for a broader class of models allowing such cataclysmic events. We discuss popular pitfalls and hidden priors.

Journal Article↗
PubMed2001

Going like gangbusters: transnational tobacco companies "making a killing" in South America.

This article reports on the recent growth of transnational tobacco companies (TTCs) in South America. Although some scholarly attention has been directed toward such growth in Asia and eastern Europe, South America has also been targeted by the TTCs' aggressive expansionist practices in recent years. Fighting "Big Tobacco" is entirely different from combating most public health problems. Unlike cigarettes, most infectious diseases and maternal and child health problems never provide profits to transnational corporations and governments. Also, most public health problems (with alcohol being another notable exception) are not exacerbated by extensive advertising campaigns that promote the cause of the health problems. Supported by data gathered during three months of fieldwork in Ecuador, Peru, Chile, and Argentina in 1997, this article suggests that the TTCs' marketing strategies override cultural differences in the choices people make regarding smoking and health. Combining critical medical anthropology and public health, this article concludes that unless dramatic actions are taken, an avoidable outbreak of tobacco-related diseases will eventually reach epidemic proportions on the South American continent. It is also a "call to arms" for more medical anthropologists to investigate tobacco-related matters around the world.

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