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Biomedical subjects

R Bauer

Publications and source records attributed to R Bauer.

At least 343 records · Page 19Linked to original sources
PubMed1990

[The detection of legionellae in a water pipe system using gene probe technics and culture methods].

In a new hospital building, cold and warm water systems were examined for microbiological parameters before opening. All of the 35 sampling sites showed elevated colony counts, i.e. greater than 100 cfu/ml. 11 of these contained Legionella species at various times. While Escherichia coli, coliform bacteria and Pseudomonas aeruginosa could not be found, Legionella longbeachae serogroup 1 + 2 was identified in 13 samples. Only one sample contained Legionella pneumophila serogroup 3. Legionella species were detected using a commercial gene probe assay and culture techniques. The gene probe method proved to be superior to the culture techniques insofar as significantly positive results were obtained more frequently, and evidence for the presence of Legionella of different species and serogroups could be obtained with a single procedure. The gene probe method appears to be a suitable screening method for the detection of Legionella species.

Colony Count, Microbial↗
PubMed1989

[Immunology in the aged].

On account of their katabolic status in general, elderly people show increasing involution of every organ and tissue. In addition to the decrease in functional vitality, we find morphologic reduction of highly differentiated cells. This process does also affect the immune system. Many diseases of old age (such as infections, malignomas, auto-immunopathies) seems to be brought about by immunodeficiency due to senescence. These diseases are promoted by the reduced production of antibodies against foreign antigens and by the decreased functions of T-suppressor subpopulations. On the other hand, we observe increasing auto-immunity, a rise of circulating immune complexes, and a higher tolerance towards alloantigenetic tissue. It is not easy to decide whether the pathologic immune status is the result of multimorbidity, or whether diseases of old age develop because of senile immunodeficiency. In this connection, our lacking knowledge regarding immunology in old age becomes obvious; moreover, the problem of answering these questions by means of systematic investigation has not yet been solved.

Aged↗
PubMed1989

[Epidermal reticular CD1 pattern].

183 biopsies taken from various skin diseases as well as normal skin were studied in cryostat sections by means of the avidin-biotin complex immunoperoxidase technique, using monoclonal antibody anti-Leu 6, which is directed against the Langerhans cell antigen CD1. In 47 cases, we observed a reticular, pemphigus-like intercellular pattern. This pattern was neither correlated to individual skin diseases, nor to the quality or quantity of corial or epidermotropic infiltrates, nor to the HLA-DR expression of keratinocytes, nor to the count of Langerhans cells. There was, however, a correlation to the presence of Langerhans cells: This pattern was never observed in the aerosyringia or deep infundibula. We conclude, therefore, that the stained antigen has to be regarded as free CD1 derived from the Langerhans cell and diffusing into the keratinocytic intercellular spaces.

Antigens, CD1↗
PubMed1989

[Classification of HIV-associated acquired immunologic deficiency syndrome].

Regarding the staging of HIV infection, there are several classification systems, but neither of them has universally been accepted. We tested a new staging system with 4 parameters: HIV antibodies, CD4/CD8 ratio, absolute count of CD4 + lymphocytes, and absolute count of leukocytes. This classification indicates a regular progression of immunodeficiency, 294 blood specimens were used for immunological staging. The correlation between the immunological staging and the severity of the disease proved the usefulness of this classification system.

CD4-Positive T-Lymphocytes↗
PubMed1989

The efficacy of nifedipine and acebutolol in coronary artery disease assessed by radionuclide ventriculography.

The efficacy of a fixed combination of 10 mg nifedipine and 100 mg acebutolol was tested in 21 patients with angiographically proven coronary artery disease (CAD). Ejection fraction (EF), emptying and filling rate (VS and VD), and end-systolic volume (ESV) were assessed by means of radionuclide ventriculography at rest and during exercise prior to as well as 1 hour and 5 hours following oral drug application. Whereas exercise-induced worsening of cardiac function had been documented in all the patients prior to medication, EF and ESV improved significantly after drug administration.

Acebutolol↗
PubMed1989

Different anisotropies of movement direction in upper and lower layers of the cat's area 18 and their implications for global optic flow processing.

Cells in Area 18 of awake and behaving cats were tested for directional preference with a large visual noise pattern. Upper and lower layer cells were found to exhibit different anisotropies for movement direction, offset by 90 degrees. These findings could reflect different functions for the global mapping and processing of optic flow field in upper and lower layers.

Animals↗
PubMed1989

Complementary global maps for orientation coding in upper and lower layers of the monkey's foveal striate cortex.

A population of 269 cells recorded from the foveal representation of striate cortex in 2 rhesus macaque monkeys was examined for orientation preference as a function of receptive field position relative to the center of gaze. Cells recorded in supragranular and infragranular layers were segregated and compared. Within the foveolar region (0.0-0.5 degrees) supragranular cells showed a vertical bias which was not evident in the infragranular layers. At larger eccentricities (0.5-2.5 degrees) supragranular cells showed a radial bias (preferred orientation points toward the center of gaze), whereas infragranular cells showed a concentric bias (preferred orientation is tangent to a circle around the center of gaze). These results are consistent with our earlier report of an orientation shift between the supragranular and infragranular layers (Bauer et al. 1980, 1983; Dow and Bauer 1984). The diagonal orientation bias which we noted earlier (Bauer et al. 1980; Dow and Bauer 1984) in supragranular cells at eccentricities between 0.5 and 2.5 degrees can be explained by the radial bias, combined with a tendency for recording sites to favor receptive field locations closer to the diagonal meridia than to either the horizontal or vertical meridia. Given other evidence that upper layer cells in macaque striate cortex tend to show either orientation or color selectivity, while lower layer cells tend to show movement sensitivity (Dow 1974; Livingstone and Hubel 1984), the present data suggest a functional dichotomy between a supragranular system involved in fixational eye movements and pattern vision and an infragranular system activated primarily by optical flow fields during ambulation.

Animals↗
PubMed1989

Evaluation of mammary blood flow measurements in lactating goats using the ultrasound Doppler principle.

1. Non-invasive methods were developed for measuring mammary blood flow in lactating goats. 2. A Doppler principle ultrasound device was equipped with an external detector measuring maximal blood velocity (Vmax) and average blood velocity (Vav) was calculated as Vmax/2. Volume flow then depended on determination of the angle of insonation and the cross-sectional area of the milk vein (the caudal superficial epigastric or subcutaneous abdominal vein). 3. Blood velocities were measured on the milk vein of either side of the animal while clamping the pudendal veins manually. Blood velocities ranged from 7-34 cm/sec. 4. The milk vein diameter was measured by means of a slide gauge which, for clearly protruding veins, gave similar results to that measured by ultrasound scanning. In protruding veins the cross-section was circular. In non-protruding veins the cross-section was elliptical and the slide gauge significantly (P less than 0.01) overestimated the cross-sectional area. The milk vein diameter of either side measured in 10 lactating goats was 8.8 +/- 1.1 mm (means +/- SD). 5. Blood flow ranged from 90-675 ml/min in a dry and a high-yielding (3.4 l milk daily) goat, respectively. The reproducibility of the blood flow measurements was 12-16%. 6. It is concluded that the present method may be used for quantitative measurements of mammary blood flow in goats.

Animals↗
PubMed1989

Iso- and cross-oriented columns in cat striate cortex: a study with simultaneous single- and multi-unit recordings.

The constancy of orientation tuning in vertical columns of the visual cortex of the cat was examined with conventional and newly developed multi-electrode methods. Preferred orientation was measured with single- and multi-unit recordings in 68 penetrations approximately perpendicular to the cortical layers and with inter-recording steps of only 40-70 microns. The tuning curves obtained revealed three types of penetration sequences: no-shift penetrations (37%), one-shift penetrations (41%) and double-shift penetrations (22%). Particular attention was paid to the orientation tuning at the transition zones below layer IV. The use of the multi-unit recording technique enabled the measurement of cross-oriented activity within a single electrode position mostly around the border between layers IV and V. Altering the type of anaesthesia (ventilation with room air or nitrous oxide-oxygen) produced only a quantitative change in the percentage of the encountered penetration types. The results suggest that upper and lower layers follow different principles of functional organization. As a consequence different types of columns, especially iso- and cross-oriented ones, are produced in a systematic way.

Animals↗
PubMed1989

Two-color flow cytometry analysis in alopecia areata.

Since previous studies have shown that circulating T cytotoxic/suppressor cells and natural killer cells are reduced in alopecia areata (AA), we attempted to find further imbalances in mononuclear cells by double labeling with these and additional monoclonal antibodies. In all, the blood of 35 patients and 44 controls was examined using the combinations anti-Leu 3a/8, Leu 2a/8, Leu 2a/15, Leu 7/15 and Leu 7/11a. We found a highly significant reduction of the subpopulation Leu 2a+8+ (p less than 0.008). The results show that patients with AA have additional abnormalities of the circulating mononuclear cells, whereby the reduced Leu 2a+8+ subpopulation represents a new additional marker.

Adolescent↗
PubMed1989

Effects of hypoxic hypoxia on the kinetics of synaptosomal Ca2+-ATPase activity in newborn piglets and young rabbits.

Severe hypoxic hypoxia with electrophysiologically detectable involvement of the brain caused a distinct alteration of synaptosomal membrane Ca2+ATPase activity in newborn piglets (n = 7) and young rabbits (n = 7). This was shown by means of the shifted pCa2+ for maximum stimulation towards higher Ca2+ concentrations and a significant decrease of the maximum activity in both species. Furthermore, an additional stimulation using supramaximum amount of exogeneous calmodulin (tested on piglets) was completely abolished after hypoxia. It is suggested that this effect might influence the fine regulation of neuronal Ca2+ homeostasis also during the posthypoxic recovery period.

Animals↗
PubMed1989

Restricted cardiovascular and cerebral performance of intra-uterine growth retarded newborn piglets during severe hypoxia.

In 7 term born two-day-old intra-uterine growth retarded (IUGR) piglets cardio- and cerebrovascular, metabolic and EEG reactions were studied at rest and during severe hypoxia in comparison to 17 normal-weight piglets. In IUGR piglets even in control conditions a distinct cerebral blood flow (CBF) elevation, lower cerebrovascular resistance and oxygen consumption in the higher perfused brain regions at diminished arterial blood pressure were observed. Also the arterial glucose concentration was in the borderline hypoglycemic range, however, cerebral glucose delivery was nearly maintained. IUGR piglets survived a 1-h hypoxic period (paO2 = 25-30 mmHg) less frequently. The main reason was the distinctly restricted emergency reaction with a lack of arterial blood pressure increase and blood glucose elevation as well as a reduced (higher perfused brain regions) or absent CBF increase (lower perfused brain regions). Thereby, even in the early stage of hypoxia cerebral oxygen delivery in both brain compartments and oxygen consumption in the latter were decreased followed by a further decrease of the arterial blood pressure. The latter factor was essential for acute cardio-vascular-cerebral insufficiency.

Animals↗
PubMed1989

[The surgical treatment of kyphosis with special reference to ventral bone span support].

Eighty-three patients with kyphosis of different etiology underwent operative correction. The results obtained in 65 of these patients after an average follow-up of 5.2 years are reported. The operative treatment produced regression of neurologic deficit in 63%, and most patients were relieved of their disabling preoperative pain. There were 3 cases of pseudoarthrosis and instrumentation failure. The four stages of operative treatment of kyphosis consist of: mobilizing osteotomy, correction, anterior and/or posterior fusion, stabilization without fusion (tumor). The indications for surgery and the choice of surgical technique are discussed. The importance of anterior fusion is emphasized.

Adult↗