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Biomedical subjects

R Meyer

Publications and source records attributed to R Meyer.

At least 235 records · Page 13Linked to original sources
PubMed1991

[Studies on the effects of air pollution on health of the population of Annaberg district with special reference to acute respiratory diseases].

From 1978 to 1988 in the district of Annaberg (Saxony, state frontier to Czechoslovakia) investigations were accomplished to assess the state of health in people living there. The southern part of the district rises to a crest (Saxon Ore Mountains). It is influenced by air pollution from Northern Bohemia. The incidence of acute infections of the upper airways showed a remarkable dependence on the degree of air pollution in the age groups up to 18 years, especially in the group of infants. In the polluted area (high overload) the morbidity of infants was 7-fold in relation to the unpolluted area of the district. In the polluted area when temperature was lower than -5 degrees C the incidence of acute respiratory infections in infants closely correlated (r = 0.90) with the concentration of SO2 in ambient air. In the town Annaberg (urban air pollution) the frequency of absence of children from school caused by acute respiratory infections was elevated in relation to the rural parts of the district, but there were no differences among these rural parts. In the polluted area the severe stages of cardiorespiratory diseases were passed through with evident acceleration. In healthy adults living there the mean values for immunoglobulins of class A and class M tended to be elevated, and in school children the antibody titers against influenza A and B were increased.

Adolescent↗
PubMed1991

Visualization and measurement of calcium transients in Amoeba proteus by fura-2 fluorescence.

A fura-2 microspectrofluorimeter was used to visualize and measure intracellular calcium transients in normal locomoting and experimentally treated Amoeba proteus. The results show that subcellular heterogeneities of cytosolic free calcium, [Ca2+]i, correlate in time and distribution with characteristic patterns of protoplasmic streaming and ameboid movement. In detail, calcium ions have a dual effect by regulating both the contractile activities of the actomyosin cortex and the rheological properties of the cytoplasmic matrix. A high resting [Ca2+]i of 1.5 to 2.0 x 10(-7) M in the uroid region or in retracting pseudopodia is associated with the transformation of rigid ectoplasmic gel into fluid endoplasmic sol, and a low [Ca2+]i of 10(-9) to 10(-8) M in the front region or in extending pseudopodia with the re-transformation of endoplasmic sol into ectoplasmic gel. Locally increased peripheral [Ca2+]i accumulations higher than 10(-7) M are also observed at places where the actomyosin cortex is known to generate motive force by contraction, i.e., in the intermediate region of orthotactic amebas or in large pseudopodia of polytactic cells. External application of 30 mM KCl abolishes the intracellular Ca2+ gradient such that [Ca2+]i attains a uniform distribution and a maximum concentration of 2 x 10(-7) M; as a consequence, cells can show a transient loss of their locomotor activity and polarity by undergoing spherulation and total contraction. On the other hand, high external Ca2+ concentrations in the range of 100 mM stabilize the bipolar cellular organization, enhance the movement velocity and induce the propagation of Ca2+ waves repeatedly running from the uroid to the front region. The significance of external ions for signal transmission and the control of dynamic activities as well as the origin and fate of calcium participating in the observed transients are discussed.

Amoeba↗
PubMed1990

The principles of the up-to-date breast reduction.

In all cases of moderate- to high-grade hypertrophy of the breast, with or without ptosis, the author emphasizes that the reduction mammaplasty with L-shaped suture lines proves to be an effective method that avoids unacceptable scars extending to the midline of the thorax, especially in the young patient.

Age Factors↗
PubMed1990

Diagnosis of iron-deficiency anemia in the elderly.

PURPOSE: To determine the value of serum ferritin, mean cell volume, transferrin saturation, and free erythrocyte protoporphyrin in the diagnosis of iron-deficiency anemia in the elderly. PATIENTS AND METHODS: We prospectively studied consecutive eligible and consenting anemic patients over the age of 65 years, who underwent blood tests and bone marrow aspiration. The study consisted of 259 inpatients and outpatients at two community hospitals in whom a complete blood count processed by the hospital laboratory demonstrated previously undiagnosed anemia (men: hemoglobin level less than 12 g/dL; women: hemoglobin level less than 11.0 g/dL). RESULTS: Thirty-six percent of our patients had no demonstrable marrow iron and were classified as being iron-deficient. The serum ferritin was the best test for distinguishing those with iron deficiency from those who were not iron-deficient. No other test added clinically important information. The likelihood ratios associated with the serum ferritin level were as follows: greater than 100 micrograms/L, 0.13; greater than 45 micrograms/L but less than or equal to 100 micrograms/L, 0.46; greater than 18 micrograms/L but less than or equal to 45 micrograms/L, 3.12; and less than or equal to 18 micrograms/L, 41.47. These results indicate that values up to 45 micrograms/L increase the likelihood of iron deficiency, whereas values over 45 micrograms/L decrease the likelihood of iron deficiency. Seventy-two percent of those who were not iron-deficient had serum ferritin values greater than 100 micrograms/L, and in populations with a prevalence of iron deficiency of less than 40%, values of greater than 100 micrograms/L reduce the probability of iron deficiency to under 10%. Fifty-five percent of the iron-deficient patients had serum ferritin values of less than 18 micrograms/L, and in populations with a prevalence of iron deficiency of greater than 20%, values of less than 18 micrograms/L increase the probability of iron deficiency to over 95%.

Aged↗
PubMed1990

The cell surface of isolated cardiac myocytes--a light microscope study with use of fluorochrome-coupled lectins.

In cells isolated from guinea-pig or rat ventricular muscle occurrence and distribution of carbohydrate components of the surface coat were monitored using fluorochrome-coupled lectins. Fluorescence of membrane-bound lectins was assayed by an image analysis system. The lectins ConA, WGA, sWGA, LFA and RCA-I showed specific binding to the whole myocyte surface, indicating a homogeneous distribution of alpha-mannosyl, alpha-glycosyl, N-acetylglucosaminyl, N-acetylneuraminate and beta-galactosyl residues. Binding of DBA and SBA, with specific affinity for N-acetylgalactosaminyl residues, to guinea-pig cardiac myocytes was mainly at the cell poles corresponding to intercalated discs in intact tissue. Both lectins failed to interact with rat myocytes. UEA-I, specific for alpha-L-fucose, bound slightly to rat and not to guinea-pig myocytes. Binding of PNA to guinea-pig myocytes was observed only after cleaving off sialic acids from cell surface, suggesting that sialic acids mask galactosyl-beta(1,3)-N-acetylgalactosamine residues. Specificity of lectin-cell interaction was tested by an inhibition assay where free sugars were tested for their capacity to inhibit lectin binding to the myocytes. When comparing different isolation procedures based on different proteolytic enzymes, the myocytes' affinity to any lectin was found to be qualitatively unchanged. Investigation of lectin-decorated myocytes by means of confocal laser scan microscopy showed that lectin binding sites are not confined to the cell surface but are also present in sarcolemmal invaginations, i.e. transverse tubules. This suggests that the tubular system is lined with a carbohydrate layer similar to, and continuous with, that of the peripheral cell surface.

Animals↗
PubMed1990

The effect of exercise and induced expectations on visceral perception in asthmatic patients.

It is assumed that visceral perception of the asthmatic patient is not only influenced by the physiological response itself but also by cognitions, i.e. specific illness related attitudes and expectations. Thirty-two adult asthmatics were studied in a 2 X 2-factorial design to examine the effect of physical exercise due to an ergometer capacity test (set at a load of 40 and 80 watt respectively) and induced expectations about the consequences of this task on broncho-constriction. Two sets of instructions were used to induce anticipations of harmful and non-harmful consequences respectively. The following dependent variables were registered: airways resistance, skin resistance and visceral perception (rating of physiological changes). Before the experiment the habitual way of reacting to asthma-relevant cues in each subject was assessed. Only small effects of the different ergometer loads on physiological responding and no effects of the experimental variables on visceral perception were found using an analysis of variance approach. A covariance analysis, however, using the trait variable as covariate, demonstrated that the induced 'harmful' anticipation significantly intensified the perception of visceral changes and even had some influence on asthma-relevant physiological responding.

Adolescent↗
PubMed1990

Lip surgery.

Explore the source record for details and available documents.

Adult↗
PubMed1990

Increased gap junction assembly between cultured cells upon cholesterol supplementation.

Novikoff hepatoma cells provide an excellent model system for the study of gap junction assembly, a process that could be influenced by lipids and other factors at numerous points. Since it is possible to alter the cellular levels of cholesterol in these cells, it was added to the cells in serum-supplemented medium and changes in gap junction assembly were evaluated. Cells were dissociated and reaggregated following exposure to a range of cholesterol concentrations for 24 h. A five- to sixfold increase in the number of aggregated gap junction particles and a 50% increase in cellular cholesterol content were observed with 20 microM added cholesterol. A 1-h exposure to added cholesterol, during cell reaggregation, resulted in a fourfold increase in the number of aggregated gap junction particles, demonstrating that the effect was rapid. The number of aggregated gap junction particles and formation plaque areas were used as measures of junction assembly and assayed by quantitative freeze-fracture and electron microscopy. Junctional permeabilities were evaluated by means of dye transfer times following the intracellular microinjection of Lucifer Yellow. Increased dye transfer was observed between cholesterol-treated cells, which suggested that the increase in assembly was accompanied by an increase in junction permeability. Cells were treated with cycloheximide (100 micrograms ml-1) and actinomycin D (10 micrograms ml-1) to determine whether protein and RNA syntheses were involved in the enhanced gap junction assembly. Cycloheximide but not actinomycin D blocked the increased junction assembly observed with added cholesterol. These results suggested that protein synthesis, but not RNA synthesis, is necessary for the increased gap junction formation observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Maintenance of human epididymal epithelial cell function in monolayer culture.

Cells liberated by enzyme treatment of tubules dissected out of human epididymides obtained at castration for prostatic carcinoma were cultured for up to 42 days on permeable supports. Outgrowth and monolayer formation was unrelated to the age of the patient or his treatment with anti-androgens. The cells comprising the monolayer were cuboidal and shorter than those in situ but their ultrastructure was characteristic of epithelial cells. There was no evidence of smooth muscle cells or fibroblast overgrowth. The cells manifested fluid-phase and adsorptive endocytosis from both apical and baso-lateral aspects and released into the medium alkaline and acid phosphatases and N-acetylglucosaminidase.

Acetylglucosaminidase↗
PubMed1990

[The possible significance of coronary vascular resistance in chronic ischemic heart disease].

From a pool of patients, treated because of cardiac diseases on ward for 4 years, 8 subjects, the mean age of which amounted to 46 (SD 12) years, showing stable angina pectoris in usual physical activity, were chosen. In these patients widespread examinations including invasive procedures had not been evident for one of the well defined heart diseases. In two patients dysrhythmias appeared during standardized exercise test while in four other subjects acute cardiac findings consisted of chest pain, significant depression of ST segments or inversion of T waves were observed. One patient had a normal result of the exercise test. A myocardial thallium-201 imaging was performed in four subjects. In three patients imaging showed questionable or mild signs of ischemia. The result suggest the existence of unknown shapes in coronary heart disease, the origin of which is possibly connected with a disorder of microvascular smooth muscle reactivity.

Adult↗
PubMed1990

[Bodily movement of teeth in atrophic jaw segments].

This experimental animal study was conducted to evaluate the extent of bone restructuring after bodily movement of teeth into an area of atrophied alveolar bone. The measured values as well as the radiographic and histologic data indicate that partial or total bone restructuring occurs depending on the rate of tooth movement. In our experiment we observed marked bone formation at an average tooth movement rate of 15 microns/day, whereas no noteworthy bone formation occurred at higher rates of tooth movement (26-40 microns/day). Basically, an improvement in attachment is possible with bodily movement in atrophic alveolar bone. However, it is important to remember the delayed periosteal reaction when planning the mechanics to be applied.

Alveolar Bone Loss↗
PubMed1990

[Intrusion of periodontally affected teeth using a polyglactin-910-membrane (Vicryl)].

The present study was to determine, if the use of a Vicryl membrane following a full flap procedure and combined with subsequent orthodontic intrusion renders the formation of new attachment more predictable. In an animal experiment eight premolars with reduced periodontia were intruded. The findings were analyzed histologically, histometrically and radiologically. The results provided the basis for a new general classification of the formation of new cementum and bone substance. This classification may serve as a reference system for future studies. The combined orthodontic/periodontologic approach resulted in complete repair and functional restructuring of the destructed interradicular bone and may be a promising alternative in the treatment of furcation invasion. The proximal root surfaces showed less increase in attachment or even further bone loss. Histometric comparison revealed no significant differences between interradicular and proximal root surfaces.

Alveolar Bone Loss↗
PubMed1990

Clinical and roentgenographic evaluation of noncemented porous-coated anatomic medullary locking (AML) and porous-coated anatomic (PCA) total hip arthroplasties.

Eighty-four primary noncemented porous-coated total hip arthroplasties (THAs) in 78 patients were reviewed clinically and roentgenographically at an average follow-up period of 37 months. The average patient age was 51.9 years. Sixty-four Anatomic Medullary Locking (AML) devices were placed in 58 patients, and 20 Porous-Coated Anatomic (PCA) devices were placed in 20 patients. The AML devices had been in situ an average of 36 months (range, 24-49 months), and the PCA devices had been in situ an average of 40 months (range, 29-51 months). The average patient ages were 52.7 and 49.2 years for AML and PCA patients, respectively. The AML devices included three that were fully coated, 59 that were five-eighths coated, and two that were one-third coated. The average preoperative Harris hip score was 38.2 for the AML devices and 33.2 for the PCA devices. The average postoperative Harris hip score was 80.7 for the AML devices and 83.8 for the PCA devices. Pain related to the implant was present in 30% of the AML devices and 30% of the PCA devices. Roentgenographically, no component demonstrated complete radiolucency, and all components demonstrated roentgenographic evidence of bone ingrowth. Roentgenographic changes with time noted for both the AML and PCA devices included: neck roundoff, neck osteolysis, neck corticocancellization, endosteal bone bridging, and distal hypertrophy. On roentgenographic zonal analysis, radiolucency greater than 1 mm was observed most frequently in the most proximal lateral zone and distal tip of the femoral component. The current series of cases, although clinically acceptable, does not support the current widespread enthusiasm for primary noncemented AML and PCA total hip systems. Cemented THA appears to produce superior clinical results, particularly when contemporary cementing techniques are employed.

Adult↗
PubMed1989

Purification of synthetic peptides on a high-resolution preparative reversed-phase column.

A 2-in. I.D. column filled with 10-microns spherical C18 bonded silica with 120 A pores was used for the preparative purification of various synthetic peptides in one step. The small-sized silica packing afforded high resolution and the spherical shape helped maintain a relatively low back-pressure during the chromatography. Conditions for performing the separations were derived from the analytical chromatography of samples on a column of similar 5-microns material. The same amount of organic modifier, but with the gradient duration increased, achieved very similar separations on the preparative column.

Amino Acid Sequence↗
PubMed1989

[Therapeutic principles in myocarditis].

The incomplete aetiopathogenetic knowledge, the non-uniform clinical and diagnostic criteria as well as the course of the myocarditis which is prognostically not to be foreseen cause controversial therapeutic consequences. In the first place of the treatment is the causal treatment of the factors evoking or maintaining the inflammation. By means of immunosuppression an improvement of the findings is obtained in approximately 50% of the patients with myocarditis. Thus the immunosuppressive therapy cannot be recommended in general. It is sought for new active agents. The disturbed haemodynamics is, apart from medicamentous measures, positively influenced above all by convalescent treatment. Individually reconciled measures of the complex rehabilitation are accompanyingly necessary and render possible an improvement of the quality of life at long sight. In individual cases only the heart transplantation may have a favourable influence on the prognosis of the in most cases young patients.

Adult↗