Search PubMed⌕ Search

Biomedical subjects

R Meyer

Publications and source records attributed to R Meyer.

At least 307 records · Page 17Linked to original sources
PubMed1985

Reverse transsulfuration and its relationship to thienamycin biosynthesis in Streptomyces cattleya.

Cystathionine gamma-lyase (EC 4.4.1.1) was purified from Streptomyces cattleya, an actinomycete which produces the unusual beta-lactam antibiotic thienamycin. The enzyme displays broad substrate specificity and is similar to gamma-lyases purified from other microorganisms. That the gamma-lyase functions in vivo to provide cysteine for antibiotic synthesis was shown by two types of experiments. First, cystathionine and methionine, as well as cysteine itself, are efficiently utilized by S. cattleya for thienamycin biosynthesis. Second, propargylglycine, a mechanism-based inactivator of cystathionine gamma-lyase in vitro, inhibits the synthesis of thienamycin in vivo. This inhibition can be substantially reversed by providing the cells with another source of cysteine, such as cystine.

Alkynes↗
PubMed1985

Interferon system in acute transient synovitis.

The interferon system of 20 children aged 2 to 11 years (mean 5 years), diagnosed as having transient synovitis of the hip by clinical criteria, was studied. The mean blood interferon concentration was significantly higher than that of normal children, and the incidence of an antiviral state of cells (in 78% of patients) was also significantly higher than in the control group. These findings are compatible with the hypothesis that the aetiology of transient synovitis is an acute, possibly unusual, viral infection.

Acute Disease↗
PubMed1985

Changes of body temperature and heat in cardiac surgical patients.

Changes in body temperature were assessed in ten adult patients undergoing surgery involving cardiopulmonary bypass (CPB) and induced hypothermia. Intraoperatively, in comparable time intervals before CPB and after rewarming, the patients lost body heat. Between the time of induction of anaesthesia and CPB, the temperature of blood in the pulmonary artery fell 1.46 (SD 0.28 degrees C); between CPB and the end of surgery the fall was 1.55 (SD 0.86 degrees C). The extent of spontaneous hypothermia did not correlate with the amount of subcutaneous fat. Hypothermia was induced to obtain a stable deep body temperature of 27.2 (SD 1.3) degrees C, when mean skin temperature averaged 2 degrees C higher. The CPB machine returned approximately 2000 kJ of heat in the rewarming period, to produce pulmonary artery and mean skin temperatures of 37.1 (SD 0.7) degrees C and 31.4 (SD 2.1) degrees C respectively. Intraoperative deep body temperatures demonstrated the expected exponential relationship with metabolic rate. Postoperatively, increase in metabolic rate was associated with rising deep body and skin temperatures. Low resistance to the flow of heat toward the skin surface was demonstrated by low postoperative values for thermal insulation, which may indicate good peripheral perfusion seen during continuing vasodilator therapy.

Body Temperature↗
PubMed1985

Good health: whose responsibility?

The individual responsibility ideology with respect to health is examined. First the concept of health is discussed, then the factors that determine health are analyzed and finally questions are raised regarding the impact of this ideology on health and the provision of health care services. Implications for social work are also considered.

Attitude to Health↗
PubMed1985

The influence of different cryopreparations on the distribution of ions in bullfrog myocard cells.

Bullfrog heart muscle trabecula are shock-frozen in liquid propane cooled by liquid nitrogen and then processed for X-ray microanalysis in two different ways: 1. Freeze-drying followed by vacuum embedding. 2. Cryoultramicrotomy and freeze-drying. Stained sections of freeze-dried, embedded tissue exhibit detailed ultrastructure, but are useless for X-ray microanalysis. Unstained, dry cut plastic-sections are suitable for X-ray microanalysis, but the ultrastructure appears faint. Higher electron optical contrast and peak-to-background ratio of X-ray spectra are generally obtained in freeze-dried cryosections. Both preparation methods show that the X-ray spectra are influenced by the quality of cryofixation. The phosphorus/potassium ratio in nuclei increases with increasing ice crystal size.

Animals↗
PubMed1985

[Plasma and synovial beta-2-microglobulin. Results of a personal study].

Beta-2-microglobulin was assayed in the plasma and the synovial fluid in 41 subjects with mechanical joint disorders, 27 patients with rheumatoid arthritis and 32 patients with non-rheumatoid arthritis. The plasma beta-2-microglobulin may be raised in all forms of joint disease, especially in the course of rheumatoid arthritis, but its ability to discriminate between rheumatoid arthritis and other forms of inflammatory joint disease is poor. In contrast, for the beta-2-microglobulin level in the synovial fluid, the differences in the means are highly significant between rheumatoid arthritis and non-rheumatoid arthritis. Concentrations of beta-2-microglobulin in the synovial fluid greater than 5.2 micrograms/ml, in this study which excluded patients with renal failure, were 100 per cent specific for rheumatoid arthritis and were found in 52 per cent of cases. However, this result has to be interpreted in the light of the fact that any extra-articular cause for an increased plasma beta-2-microglobulin, particularly renal failure, also causes a rise in the synovial concentration, invalidating the test. For this reason, the authors propose using the value of the beta-2-microglobulin in the synovial fluid minus the plasma beta-2-microglobulin, as a more specific index.

Arthritis↗
PubMed1985

CT guided percutaneous fine-needle biopsy of the pancreas.

147 CT guided fine-needle biopsies of the pancreas were carried out on 141 patients (45 malignant tumours, 79 chronic pancreatitis and pancreas without lesions, respectively). In 23 pseudocysts a malignant lesion could be excluded. By analysing the remaining 124 biopsies (non-cystic targets) an overall accuracy of 79%, a sensitivity of 71% and a specificity of 84% in differentiating between benign and malignant lesions were obtained. By excluding 12% of biopsies with no diagnostic material, an overall accuracy of 90% might be recorded. The comparison between the number of aspirates per examination and the cytological diagnoses would indicate that a minimum of four aspirates is required for satisfactory results.

Biopsy, Needle↗
PubMed1985

X-ray microanalysis in cryosections of natively frozen Paramecium caudatum with regard to ion distribution in ciliates.

Cells of Paramecium caudatum were shock-frozen without pretreatment for cryoultramicrotomy and freeze-dried for subsequent X-ray microanalysis. Na, Mg, P, S, Cl, K, and Ca were detected in different amounts in several subcellular compartments. In particular, calcium was localized below the cell surface (pellicle). Trichocysts were found to contain significant amounts of Na in their base but not in the tip. Na, Mg, P, S, Cl, K, Ca were found in electron dense deposits within the lumen of the contractile vacuole. A small K concentration was found in the cytoplasm and in the mitochondria. X-ray microanalysis of the element distribution in different subcellular compartments provides information for the understanding of cellular functions such as exocytosis, locomotion, and ion regulation.

Animals↗
PubMed1985

[The toxicologic evaluation of biomaterials. 1. Results of biomaterial tests in cultures of human amnion epithelial cells and human fibroblasts].

Cell cultures are a highly sensitive toxicological model used also for the testing of biomaterials. Beside the safety tests provided in the Pharmacopoeia of GDR cultures from human amnionepithelial cells and fibroblasts are used. The paper reports the results of some methodical investigations concerning the procedure of extraction of biomaterials, the evaluation of test results and the comparison with the results of other biological tests.

Amnion↗
PubMed1984

Structural and replicative forms of mitochondrial DNA in tissues from adult and senescent BALB/c mice and Fischer 344 rats.

Age-related changes in the structure and replication of mitochondrial DNA (mtDNA) were investigated in different organs from young adult (9-10 months' old) and senescent (28-29 months' old) BALB/c mice and Fischer 344 rats. Total mtDNA from brain, heart, kidney and liver was isolated by centrifugation in ethidium bromide-CsCl gradients and examined for the occurrence of complex forms and replicative intermediates by electron microscopy. The frequency of catenated mtDNA (interlinked molecules containing two or more circular units) varied from about 2.5% to 5% in adult tissues and showed a small increase in the majority of senescent organs. The frequency of double-sized circular molecules, or circular dimers, was very low in adult tissues, with an average of about 0.04% in mice and 0.1% in rats. The frequency of circular dimers increased with aging to 1.9% in mouse brain and 1.5% in rat kidney, with smaller increases (0.4% and 0.7%) in heart mtDNA from both species; there was no significant increase in the other organs. It is suggested that the increase in the frequency of circular dimer mtDNA reflects an overall deterioration of tissue physiology rather than intrinsic senescent changes in the mitochondria. The frequencies and types of the various replicative forms of mtDNA varied significantly according to tissue but not according to species or donor age. The only exception was a significant increase in the frequency of larger replicative forms in senescent mouse liver, to about 20% compared with 12% in adult liver, suggesting an age-related change in the rate of mtDNA replication and/or turnover in this organ.

Aging↗
PubMed1984

[Analysis of the results of 96 CT-guided fine needle biopsies of liver masses].

A prospective study of 96 CT-guided fine needle biopsies in 93 patients showed 47 malignant and 46 benign lesions in the liver. Overall accuracy was 97%, with a sensitivity of 92% as specificity of 96%. At least four punctures per biopsy were necessary for a reliable diagnosis. In order to save time, fine needle biopsy is recommended to be carried out immediately after the initial CT.

Adolescent↗
PubMed1984

[Self-description of a depressive patient--on William Cowper's pathobiography].

The life of an English poet of the eighteenth century who suffered from periodic depression, i.e. phasic depressive illness, is described. The study is based on a short autobiography and mainly on more than 400 dated letters addressed to a small number of relatives and friends. These sources allow the diagnostic evaluation, the description of the symptomatology and its change during the course of his illness. In their personal style these letters express the suffering during melancholy and the mastering of these experiences after recovery, within the framework of his religious convictions. The possibilities of care and treatment of a depressive patient at that time are also considered.

Depressive Disorder↗