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Biomedical subjects

G Keller

Publications and source records attributed to G Keller.

At least 163 records · Page 9Linked to original sources
PubMed1978

[A study of the retinal pigmentary epithelium in vitro (author's transl)].

The different phases of phagocytosis by retinal pigment epithelium in vitro were studied by scanning (SEM) and transmission electron microscopy (TEM). Organotypical and histiotypical cells were stimulated by polystyrene microspheres in the presence of inhibitors of microfilament contraction (cytochalasine B) and cellular translocation (colchicine). The possible function of microfilaments and microtubules during the phagocytosis is briefly discussed.

Animals↗
PubMed1977

Effects of colchicine on phagosome-lysosome interaction in retinal pigment epithelium. II. In vitro observations on histio-organotypical retinal pigment epithelial cells of the pig (a preliminary report).

Phagocytic activity of histiotypical and organotypical retinal pigment epithelial cells was studied by SEM and EM. After a latent period polystyrene microspheres of different diameter were captured by newly formed microvilli. No mechanism of discrimination according to the size of microspheres was observed. After engulfment, microvilli of histiotypical cells decreased in length and finally disappeared. Lysosomes increased in number when compared to unstimulated cells and fused with many latex-containing phagosomes. Colchicine, when added at 5 X 10(-5) M to the medium, inhibits phagosome-lysome interaction, thus confirming in vivo observations.

Animals↗
PubMed1977

Inactivation of lipid-containing viruses by long-chain alcohols.

This report describes the inactivation of lipid-containing viruses by several long-chain alcohols. A striking peak in antiviral activity was found for saturated alcohols having chain lengths from 10 to 14 carbons. Viruses having different membrane structure showed different susceptibilities to alcohols having different chain lengths and structural features. Decanol, dodecanol, and tetradecanol readily inactivated herpes simplex virus and the enveloped bacterial virus phi6. The lipid-containing virus PM2 was susceptible to decanol and dodecanol but comparatively unsusceptible to tetradecanol. The branched-chain alcohol phytol, a naturally occurring component of chlorophyll, was active against phi6 and herpes simplex virus but not against PM2. Polyoma virus and the bacteriophage phi23-1-a, which do not contain lipids, were not susceptible to inactivation by any of the alcohols tested. Experiments were also carried out to determine the effects of these compounds on cells. At 0.5 mM, decanol lysed human embryonic lung cells, erythrocytes, and the bacterial hosts for phi6 and PM2. Dodecanol, tetradecanol, and phytol at this concentration were less damaging to cells. At 0.05 mM, none of the alcohols caused observable cytopathic effects on human embryonic lung cells, although several of the alcohols at this concentration were active against herpes simplex virus. Our findings suggest that dodecanol, tetradecanol, and phytol may warrant further studies as potential antiviral agents, particularly for topical application to virus-infected areas of the skin.

Antiviral Agents↗
PubMed1977

Monitoring of pulmonary fluid volume and stroke volume by impedance cardiography in patients on hemodialysis.

Changes of intrathoracic fludi volume during maintenance therapy with hemodialysis were studied in ten patients with the aid of impedance cardiography. It was found that there was a statistically significant correlation between the decrease in body weight and the increase in basic thoracic impedance in the individual patients, but the values differed considerably from one patient to another. Therefore, comparison of sequential measurements is feasible only in one and the same patient. Out of 16 patients with overhydration undergoing dialysis, the stroke volume could not be determined by impedance cardiographic studies in eight, owing to the abnormal morphology of the dZ/dt curve. Moreover, because the basic thoracic impedance was not constant during treatment, the calculated changes in stroke volume did not appear to be reliable. This has to be taken into account when repeated measurements are made under clinical conditions. In some of the patients, the dZ/dt curve displayed interesting anomalies, probably resulting from hemodynamic alterations. The diagnostic meaning of these features is not yet known.

Adult↗
PubMed1977

[Clinical and radiological aspects of dysplasia of the hip. 4th report: Radiation exposure in the early diagnosis during the first three months (Volume-dose) (author's transl)].

Calculations of the relative volume-dose for 1 and 4-month-old infants yielded a ratio of 1:2. Measurements in the phantom and newborns yielded a surface incidence dose for newborns of 1/400 of the annual environmental radiation surface incidence dose (with optimal radiographic technique). The radiation risk of the pelviogram for newborns and during the first three month period can be justified. Indicated radiographic examination for diagnostic clarification of dysplasia of the hip should not be omitted during the first three months period.

Age Factors↗
PubMed1975

[Aspects of dysplasia of the hip-joint, clinically and radiologically, 2nd communication: Remarks on clinical signs and average values of the acetabular angle during the first 3 months].

1. It is not very likely that all degrees of dysplasia of the hip-joint can be discovered with the Ortolani- or snap phenomenon. The definition of these phenomena which presumes a wideining of the acetabulum is against it. Slighter and medium degrees cannot be discerned. All aigns and symptoms however discrete have to be taken into consideration. 2. The average values and standard deviations for the acetabular angle are not sufficiently established statistically for the first 2 months. They cannot, therefore, be used.

Acetabulum↗
PubMed1975

[Refinement of mensurational methods in human pharmacology].

In healthy persons the changes in heart rate and myocardial contractility induced by oxprenolol and phentolamine are more marked in the erect position and during physical exertion then in recumbency. Similarly, a dose-effect relation with regarded to the negatively inotropic activity of oxprenolol is more readily detectable in the upright position.

Dose-Response Relationship, Drug↗
PubMed1975

[Modern viewpoints of hip joint dysplasia, clinical and radiologic. III. Radiologic follow-up].

Dysplasia of the hip-joint can unequivocally be recognized at the age of 7 weeks as proved by further developments. Defects in the acetabular angle remain in spite of abductionsplints which may have to be continued until the acetabular roof including its angle have become normal. It must not be abandoned when the PDW has returned to normal. One ought to demand that treatment should be started before this stage has been reached i.e. before the 7th week of life. 1. Clinical and radiologic observations in the first 3 months prove that dysplasia of the hip-joint can be well recognized at this early stage. A diagnosis beyond the 3rd month is a late diagnosis. 2. Essential radiologic signs are: wedge-segments, delayed ossification of the acetabular angel, "Tailliation" at the angle, subchondral sclerosis of the acetabular roof, double contour of the angle in radiographs and, in severe cases, steep PDW. 3. The averages and standard deviations of the Tonnis statistics have proved too large for the radiographs of the first 2 months of life and useless as shown in follow-up. 4. The dysplastic acetabulum is not immature but pathologic. 5. The common mild dysplasias cannot be recognized with PDW but only when searching for structural and contour changes at the acetabular roof.

Acetabulum↗