Biomedical subjects

A Meyer

Publications and source records attributed to A Meyer.

At least 307 records · Page 17Linked to original sources

PubMed1993

Alcoholic hepatitis.

Anorexia, weight loss, fatigue, symptoms of alcohol withdrawal and hepatomegaly are common early presenting signs and symptoms of alcohol abuse. The clinical diagnosis of alcoholic hepatitis can be made in alcoholics with associated fever, leukocytosis, jaundice and tender hepatomegaly. Associated laboratory abnormalities may include leukocytosis or leukopenia, anemia, a prolonged prothrombin time and elevated liver enzymes, including aspartate amino-transferase (AST), alanine aminotransferase (ALT), alkaline phosphatase and bilirubin. An AST-to-ALT ratio greater than 2 is common in patients with alcoholic hepatitis. Liver biopsy may be required to establish the diagnosis and to identify other pathology, such as cirrhosis. Histologic diagnosis of alcoholic hepatitis requires the presence of liver cell damage, an inflammatory infiltrate and fibrosis. Biopsy-proven cirrhosis with alcoholic hepatitis or a significantly elevated total bilirubin level and prolonged prothrombin time are associated with a worse prognosis. Abstinence from alcohol, nutritional supplementation and corticosteroids are the mainstays of treatment for severe alcoholic hepatitis.

Hepatitis, Alcoholic↗

PubMed1992

A waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody diarrhea and death.

OBJECTIVE: To describe and determine the source of a large outbreak of Escherichia coli O157:H7 (ECO157) infections in Missouri. DESIGN: A case-control study and a household survey. SETTING: A small city in a rural Missouri township that had an unchlorinated water supply. PATIENTS: Case patients were residents of or visitors to Burdine Township with bloody diarrhea or diarrhea and abdominal cramps occurring between 15 December 1989 and 20 January 1990. MEASUREMENTS: Escherichia coli O157 was isolated from 21 stool specimens. All isolates were resistant to sulfisoxazole, tetracycline, and streptomycin; produced Shiga-like toxins I and II; and had one 60-megadalton plasmid. RESULTS: Among the 243 case patients, 86 had bloody stools, 32 were hospitalized, 4 died, and 2 had the hemolytic uremic syndrome. In the case-control study, no food was associated with illness, but ill persons had drunk more municipal water than had controls (P = 0.04). The survey showed that, during the peak of the outbreak, bloody diarrhea was 18.2 times more likely to occur in persons living inside the city and using municipal water than in persons living outside the city and using private well water (P = 0.001). Shortly before the peak of the outbreak, 45 water meters were replaced, and two water mains ruptured. The number of new cases declined rapidly after residents were ordered to boil water and after chlorination of the water supply. CONCLUSIONS: This was the largest outbreak of ECO157 infections, the first due to a multiply resistant organism, and the first shown to be transmitted by water. System-wide chlorination as well as hyperchlorination during repairs might have prevented this outbreak. Both bloody and nonbloody diarrhea may be common manifestations of this infection, which is probably underdiagnosed because of the failure of routine stool cultures to identify the organism. Cities with deteriorating water systems using untreated water risk widespread illness from contaminated drinking water.

Adolescent↗

PubMed1992

Genetic divergence, speciation and morphological stasis in a lineage of African cichlid fishes.

Since their discovery at the turn of the century, the species assemblages of cichlid fishes in the East African Lakes Victoria, Malawi and Tanganyika have fascinated evolutionary biologists. Many models have attempted to account for the 'explosive' evolution of several hundred species within these lakes. Here we report a case of surprisingly large genetic divergence among populations of the endemic Tropheus lineage of Lake Tanganyika. This lineage of six species contains twice as much genetic variation as the entire morphologically highly diverse cichlid assemblage of Lake Malawi and six times more variation than the Lake Victoria species flock. Although it is highly variable in coloration, this group of species and its closest relatives have not undergone appreciable morphological change. The observed geographic pattern of genetic variation suggests that major lake level fluctuations affected the distribution and speciation of this lineage of cichlid fishes.

Africa↗

PubMed1992

Cytochrome b of fish mitochondria is strongly resistant to funiculosin, a powerful inhibitor of respiration.

We report here some unusual properties of ubiquinol: cytochrome c reductase of eel and other fish mitochondria. The turnover rate of the reductase is clearly higher than in mammalian mitochondria and the binding constant for ubiquinone seems to be larger than in other vertebrates. Additionally, the reductase activity of fish mitochondria is resistant to some powerful inhibitors that bind to cytochrome b, in particular to funiculosin. After sequencing most of the gene of eel cytochrome b and comparing the deduced amino acid sequence with that of other fish and animals, we hypothesize that the decreased binding of funiculosin could be due to a few amino acid replacements in the third and fourth transmembrane helix of the protein. In particular, the presence of methionine instead of alanine at position 125 seems to be largely responsible for the strong resistance to funiculosin and also to the partial resistance to myxothiazol in all fish mitochondria. Correlations between some residue substitutions in cytochrome b and the different effects of funiculosin in different species are also considered.

Amino Acid Sequence↗

PubMed1992

Prenatal diagnosis of monosomy 18 and ring chromosome 18 mosaicism.

The case of monosomy 18/ring chromosome 18 mosaicism which was detected prenatally by amniocentesis is presented. The pregnancy was terminated in week 18. Autopsy showed complex malformation of the fetus consisting of cebocephaly, hypotelorism, microphthalmia, severe defects of brain development, and arrest of placental maturation.

Adult↗

PubMed1992

Molecules, fossils, and the origin of tetrapods.

Since the discovery of the coelacanth, Latimeria chalumnae, more than 50 years ago, paleontologists and comparative morphologists have debated whether coelacanths or lungfishes, two groups of lobe-finned fishes, are the closest living relatives of land vertebrates (Tetrapoda). Previously, Meyer and Wilson (1990) determined partial DNA sequences from two conservative mitochondrial genes and found support for a close relationship of lungfishes to tetrapods. We present additional DNA sequences from the 12S rRNA mitochondrial gene for three species of the two lineages of lungfishes that were not represented in the first study: Protopterus annectens and Protopterus aethiopicus from Africa and Neoceratodus forsteri (kindly provided by B. Hedges and L. Maxson) from Australia. This extended data set tends to group the two lepidosirenid lungfish lineages (Lepidosiren and Protopterus) with Neoceratodus as their sister group. All lungfishes seem to be more closely related to tetrapods than the coelacanth is. This result appears to rule out the possibility that the coelacanth lineage gave rise to land vertebrates. The common ancestor of lungfishes and tetrapods might have possessed multiple morphological traits that are shared by lungfishes and tetrapods [Meyer and Wilson (1990) listed 14 such traits]. Those traits that seem to link Latimeria and tetrapods are arguably due to convergent evolution or reversals and not to common descent. In this way, the molecular tree facilitates an evolutionary interpretation of the morphological differences among the living forms. We recommended that the extinct groups of lobe-finned fishes be placed onto the molecular tree that has lungfishes and not the coelacanth more closely related to tetrapods. The placement of fossils would help to further interpret the sequence of morphological events and innovations associated with the origin of tetrapods but appears to be problematic because the quality of fossils is not always high enough, and differences among paleontologists in the interpretation of the fossils have stood in the way of a consensus opinion for the branching order among lobefinned fishes. Marshall and Schultze (1992) criticized the morphological analysis presented by Meyer and Wilson (1990) and suggest that 13 of the 14 morphological traits that support the sister group relationship of lungfishes and tetrapods are not shared derived characters. Here we present further alternative viewpoints to the ones of Marshall and Schultze (1992) from the paleontological literature. We argue that all available information (paleontological, neontological, and molecular data) and rigorous cladistic methodology should be used when relating fossils and extant taxa in a phylogenetic framework.

Animals↗

PubMed1992

Embryonic chicken gizzard: immunolocalization of collagen and smooth muscle myosin.

Antibodies to chicken gizzard myosin and to chicken skin collagen type I allow the myofibrillar and connective tissue development in the embryonic chicken gizzard to be followed. Fibroblasts are assumed to synthesize collagen prior to the onset of smooth muscle cell development in the muscle primordium (day 5); they are presumably also responsible for collagen synthesis close to the presumptive lamina propria and in the developing tubular glands (day 14 to 17). From day 6 to 8, myosin and collagen are colocalized intracellularly, and from day 9 onward collagen fibers start to appear extracellularly, eventually forming the trellis-like connective tissue septa that give the rhomboid profile found in the adult muscle. The close association of collagen and myosin in early development suggests that the muscle cells themselves produce and export collagen.

Animals↗

PubMed1992

Formation of benzo[a]pyrene-DNA adducts in blood monocytes from lung cancer patients with a familial history of lung cancer.

The in vitro formation of benzo[a]pyrene-DNA adducts was determined in peripheral blood monocytes of 22 lung cancer patients with at least one first-degree relative with lung cancer and compared to results obtained in 30 healthy controls. In patients, the mean (SEM) adduct formation was 2.8 (0.3) fmol/micrograms DNA as compared to 2.1 (0.1) fmol/micrograms in controls (p less than 0.05), and it was independent of age and smoking habits. These findings support the hypothesis that carcinogen-DNA adduct formation may be one factor of a constitutionally enhanced lung cancer risk.

Adenocarcinoma↗

PubMed1992

A population-based, multivariate analysis of the association between 911 access and per-capita county trauma death rates.

STUDY OBJECTIVE: Decreased response times for injury should decrease the morbidity and mortality of trauma. The 911 telephone access is designed to improve the response time for emergencies. The purpose of this study was to analyze the association between county 911 access and per-capita county trauma death rates. METHODS: Data on all trauma deaths from 1986 through 1988 were obtained from the North Carolina Medical Examiner's data base. Counties were divided into those that had 911 access during the entire study period (15), those that never had 911 access (62), and those that installed 911 during 1987 (ten). Counties obtaining 911 access in 1986 or 1988 were excluded (13). RESULTS: The per-capita trauma death rate in counties that had 911 access throughout the study was 4.3 +/- 0.8 versus 5.0 +/- 1.1 per 10,000 population in counties that never had 911 access (P less than .01). Compared with counties with 911 access, counties without 911 were more rural, were less likely to have a trauma center, and were less likely to have advanced life support certification (P less than .03 for all). Controlling for these other factors, multivariate analysis demonstrated that 911 access had no significant independent association with per-capita county trauma death rates. In the ten counties that implemented 911 access in 1987, no significant change occurred in per-capita county trauma death rates after implementation of 911. CONCLUSION: Although counties with 911 access had lower trauma death rates by t-test, multivariate analysis showed no significant independent association of 911 access with per-capita county trauma death rates. In the ten counties that implemented 911 access in 1987, no significant changes in trauma death rates occurred after implementation. Although other factors may explain these findings, this study showed no significant independent impact of 911 access on per-capita county trauma death rates.

Emergency Medical Service Communication Systems↗

PubMed1992

Cellular uptake and subcellular distribution of phosphorothioate oligonucleotides into cultured cells.

A phosphorothioate oligonucleotide that has been employed to inhibit HIV-1 viral expression in chronically infected H9 cells was examined for cellular uptake and subcellular distribution. The relationship between extracellular oligonucleotide concentration and the distribution and accumulation into subcellular organelles is important to the design, potential side effects, and understanding of a therapeutically useful antisense oligonucleotide. These studies employed uptake of both 35S- and fluorescence-labeled phosphorothioate oligonucleotides. Experiments with V79, HeLa, H9, and fresh human peripheral blood monocytes indicate that accumulations of oligonucleotide inside cells exceeds the concentration of oligonucleotide in culture media by over 100 times following 1 h of exposure at 37 degrees C. Uptake is more efficient at low concentrations, suggesting a saturable process. The total oligonucleotide that remains in cells begins to reach a plateau after 45-60 min, indicating either that efflux pathways exist or that uptake is saturable. Subcellular fractionation studies with 35S-labeled phosphorothioate demonstrate the oligonucleotide is sequestered into both the nuclei and the mitochondria of cultured HeLa cells in a time-dependent manner. The subcellular fractionation was examined with fluorescence-labeled phosphorothioate by both confocal and fluorescence microscopy, which confirmed the rate and localization of oligonucleotide into cultured cells. Finally, cellular uptake is not uniform for all cells in a nonsynchronous culture.

Animals↗

PubMed1992

Multivariate population-based analysis of the association of county trauma centers with per capita county trauma death rates.

UNLABELLED: The purpose of this study was to utilize a large population-based data base to determine the association of trauma centers with per capita county trauma death rates. METHODS: Per capita county trauma death rate, the dependent variable in the model, was obtained from a well-validated state Medical Examiner's data base. Over 200 county demographic, prehospital, and hospital trauma care resource variables were obtained from a variety of sources for multivariate modeling. Bivariate analysis identified candidate variables for multivariate modeling, excluding highly correlated independent variables to avoid problems of collinearity. Multivariate linear regression, logistic regression, and stepwise discriminant analysis were used to determine the relative association of the candidate variables with per capita county trauma death rates. RESULTS: Bivariate analysis identified multiple factors associated with per capita county trauma death rates. These included, among others: county rurality, percentage of unemployment, percentage nonwhite, 911 access, and ALS certified EMS. Per capita trauma death rates were significantly lower in counties with trauma centers compared with counties without trauma centers (4.0 +/- 0.5 and 5.0 +/- 1.1 deaths per 10,000 population, p = 0.0001, respectively). Multivariate analysis demonstrated that the presence of a trauma center in the county and ALS were the best medical system factors predicting decreased per capita county trauma death rates. CONCLUSIONS: This study is unique in utilizing a regional population-based data base of all trauma deaths in a large state to analyze the association of trauma centers and trauma death rates. Multivariate modeling controlling for other county variables demonstrated that the presence of a trauma center and Advanced Life Support training were the best predictors of per capita county trauma death rates. These findings are consistent with the hypothesis that trauma centers decrease trauma death rates.

Adult↗

PubMed1992

Unusual mitochondrial DNA polymorphism in two local populations of blue tit Parus caeruleus.

Mitochondrial DNA (mtDNA) from 25 blue tits Parus caeruleus sampled from two populations of the Grenoble region (France) was assayed for polymorphism with 17 restriction endonucleases. Nine genotypes were found. Several mtDNA genotypes were also analysed by amplification via the polymerase chain reaction (PCR) and direct sequencing of 903 bp of the cytochrome b gene. The mtDNA polymorphism is greater in P. caeruleus than in other comparable bird species and results from the presence of two clearly differentiated mitochondrial lineages. Using the data of restriction polymorphism, the mean sequence divergence between individuals of the two lineages is 1.23%. Therefore, P. caeruleus should fall into the category II of phylogeographic pattern sensu Avise et al. (1987): discontinuous mtDNA genotypes which co-occur in the same region. P. caeruleus, like humans and other mobile species with high gene flow, seems to have lost its geographic structure in terms of mtDNA phylogeny. This unusual mitochondrial polymorphism can be explained by the recent admixture of two long-term isolated populations. This could be accounted for by two different scenarios. One assumes a simultaneous post-glacial colonization of the Grenoble region by two isolated European populations of P. caeruleus. Alternatively, hybridization between P. caeruleus and P. cyanus could have caused the observed pattern of mtDNA variation.

Amino Acid Sequence↗

PubMed1992

[Eosinophilic gastroenteritis: two case reports].

Eosinophilic gastroenteritis is a rare lesion that may present a diagnostic problem to the surgeon. It may be confused with a malignant tumor because it often presents with intestinal obstruction. We treated two cases at the Hôpital de zone de Morges. In one case the lesion was in the gastric antrum and in the other the ascending colon. Only 27 cases of colonic eosinophilic gastritis are described in the medical literature.

Aged↗

PubMed1992

[Infections with enteropathogenic Escherichia coli (EPEC) in cattle. 1. Comparison of different animal models and a cell culture system for the establishment of a detection system for "attaching and effacing" (AE) lesions].

In several animals species, enteropathogenic Escherichia coli (EPEC) were described as agents causing diarrhea. The histopathogenic pattern of EPEC is due to a typical adherence to enterocytes, called "attaching and effacing" (AE). This lesions are characterized by the formation of pedestals, cups and a marked loss of microvilli on enterocytes. In view of using an "in vitro system" (HeLa-cell culture) to test the adherence of EPEC, we first tested bovine EPEC in several laboratory animals. Various strains of mice, one day chicks (peroral) and a three day old calf (ligated intestinal loops) were inoculated with a bovine pathogenic EPEC (S 102-9). The adherence of EPEC "in vivo" was histologically, electron microscopically and bacteriologically investigated and compared to adherence to HeLa cell cultures. AE-lesions were found on calf enterocytes as well as on HeLa-cells, no lesions were seen in mice and chicks. The ligated intestinal loop test seems to be a useful model to compare "in vivo" to "in vitro" adherence.

Animals↗

PubMed1991

[Biliopancreatic bypass and disorders of iron absorption].

Sideropenic anemia is a common long-term complication of surgical bilio-pancreatic bypass for morbid obesity, and is frequently resistant to oral iron therapy. To study the pathogenesis of this phenomenon we investigated 7 such patients clinically and biologically, with special emphasis on iron absorption. Our results show that sideropenia, consistently present and frequently complicated by anemia, is due to deficient iron absorption and that this malabsorption is non-selective. Replacement therapy, when indicated, should therefore use the parenteral route.

Adult↗

PubMed1991

Usefulness of electrocardiographic findings and creatine kinase levels on admission in predicting the accuracy of the interval between onset of chest pain of acute myocardial infarction and initiation of thrombolytic therapy.

Patients with chest pain lasting greater than 6 hours and suggesting acute myocardial infarction (AMI) are often excluded from thrombolytic therapy, because myocardial necrosis is believed to be largely irreversible beyond that time. To evaluate the relation between time of onset of chest pain and enzymatic evidence of myocardial necrosis, enzymes on admission were analyzed in 221 consecutive patients with greater than or equal to 2 mm ST-segment elevation by electrocardiography on admission and no contraindications to thrombolytic therapy. Patients with symptoms within 6 hours (n = 170, early) received thrombolytic therapy, but those with symptoms after 6 hours did not (n = 51, late). Eventually, 219 (168 early, 51 late) patients had enzymatically proven AMI within 24 hours. Creatine kinase levels on admission less than twice the upper normal limit were found in 155 (91%) early patients, but surprisingly, also in 30 (59%) late patients. By electrocardiography on admission, ST-segment elevation per lead was 2.1 +/- 1.1 mm in late patients with low initial enzymes versus 1.1 +/- 0.3 mm in those with elevated initial enzymes (p less than 0.0001). Concomitantly, Q waves in leads with ST-segment elevation were present in 17 (57%) late patients with low enzymes on admission versus 17 (81%) with elevated enzymes on admission (p = 0.06). Eventually, maximal creatine kinase levels were similar in all late patients irrespective of enzyme levels on admission. Therefore, many patients with symptoms of AMI after 6 hours have low enzymes on admission and may still be eligible for thrombolytic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

Malignant transformation in hepatocytes is associated with the general increase of glycoprotein ligands specifically binding to the endogenous lectin CSL.

Several hepatoma cell lines and hepatic ascite tumour cells were studied for the presence of glycoprotein ligands of an endogenous lectin, the "Cerebellar Soluble Lectin" (CSL). This lectin is also present in hepatocytes in vivo and in vitro and can be detected biochemically and immunologically. In transformed cells, the level of CSL glycoprotein ligands is increased 50-fold as compared to the control cells. Such an increase is not observed for the ligands of the plant lectin, concanavalin A, which is, as CSL, a D-mannose-binding lectin. These results indicated that the changes in glycans during malignant transformation, in these cells, is specifically important for minor glycans binding to CSL.

Animals↗

PubMed1991

[The effect of oral N-acetylcysteine on glutathione concentration in bronchoalveolar lavage of patients with fibrosing lung diseases].

Glutathione (GSH) is an important constituent in protecting the cellular elements within the lower respiratory tract against oxydants. We measured GSH in bronchoalveolar lavage fluid (BAL) in twelve patients with lung fibrosis and compared the data to eight healthy controls. GSH in BAL was 0.71 +/- 0.34 mumol/l in patients with lung fibrosis and 0.88 +/- 0.35 mumol/l in the controls (p greater than 0.05). After relating GSH on the volume of the epithelial lining fluid (ELF), determined by the urea method, GSH/ELF was 93 +/- 71 mumol/l in lung fibrosis and significantly different (p less than 0.005) from 387 +/- 240 mumol/l in the controls. In seven patients (four lung fibrosis, one desquamative pneumonitis, two asbestosis) GSH in BAL was determined before and after seven days of medication with 1800 mg N-acetylcysteine/day. We observed a significant increase of GSH in BAL from 0.93 +/- 0.46 to 1.56 +/- 0.92 mumol/l. Our observations confirm that in patients with lung fibrosis the protective ability against oxydants is diminished and that one parameter of the antioxydative capacity (GSH) can be increased in BAL by oral administration of N-acetylcysteine. Further studies are necessary to investigate the clinical and therapeutic implications of our findings.

Acetylcysteine↗