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Biomedical subjects

H Zwick

Publications and source records attributed to H Zwick.

At least 109 records · Page 6Linked to original sources
PubMed1987

Unfixed material embedded in a methacrylate resin (Technovit 7100) for immunofluorescent staining.

Wheat grains were embedded with or without fixation in Technovit 7100 or in paraffin. This enabled us to produce 4 microns sections for immunofluorescent staining to see whether serum of patients with baker's asthma contained IgG antibodies against wheat grains. Embedding without fixation in Technovit 7100 appeared to be suitable for immunofluorescent staining and gave superior results to protocols requiring fixation.

Acrylates↗
PubMed1986

Acute restraint device for rhesus monkeys.

A practical and inexpensive alternative to the standard primate chair is described. The apparatus is designed to allow easy removal of rhesus monkeys from their home cages and to allow restraint without anesthesia. A portable Plexiglas cage, which can be adjusted to accommodate rhesus monkeys of varying sizes, is placed against an animal's home cage. The animal is then trained to avoid the squeeze mechanism of the home cage by going into the Plexiglas cage. The animal's head can then be secured by means of poles hooked to a light weight collar worn permanently. This device and procedure allows an investigator to work with a restrained animal without resorting to drugs, unnecessary force or chronic restraint. Animals can be transferred daily with this technique with minimal conditioning and cooperation.

Animals↗
PubMed1984

Effects of extended hypoxia on night vision.

The effects of 16 d of sustained hypoxia (4300-m equivalent) on the dark adaptation threshold function were studied in 12 male subjects measured periodically (days 2,4,6,9,11,13,16 of exposure) over a 20-min test period for both red and green stimuli using a new computerized dark adaptometer. Comparison with sea level performance showed negligible elevations of thresholds for red response, but highly significant impairment of green response (p less than 0.00001) over almost the entire dark adaptation function. These losses peaked between the sixth and ninth day followed by little recovery, except at the eleventh day when the subjects descended briefly to 3200 m elevation. Impairments developed rapidly again upon return to the original higher altitude. The results differ from previous findings after shorter exposure periods, which showed only slight impairments of the early segment of dark adaptation. Implications of the results are discussed.

Adolescent↗
PubMed1982

Senile cataracts and myopia.

A retrospective survey of 32 persons with myopia and 38 persons with emmetropia who had been operated on at two US Army hospitals on the California coast showed that the persons with myopia who had worn eyeglasses for at least 20 years underwent cataract extraction at a significantly (P less than .00005) older age than the persons with emmetropia (median age at the time of the operation was 70 years, compared with 64 years). These results support the theory that some protection against solar ultraviolet radiation is offered the eyes by eye wear worn continuously and that solar ultraviolet radiation may be a contributing factor in the formation of human senile cataracts.

Adult↗
PubMed1981

[The assessment of cardiorespiratory performance in pulmonary emphysema (author's transl)].

In patients with pulmonary emphysema the course of PO2 and of pulmonary and systemic circulation is analysed under exercise up to the performance limit and to PO2 reduction. By alterations of breathing mechanics frequent emphysematous persons and associated with bronchial obstructions under increased intrapulmonary pressure by forced ventilation a group of patients may be found with a quick limitation of performance by hindering the intrathoracic circulation followed by reduction of the systemic blood pressure. A pulmonary arterial hypertension cannot be seen in these cases. The registration of the parameters of breathing mechanics during exercise testing is recommended.

Female↗
PubMed1980

[The flow-volume-diagram (author's transl)].

The analysis of forced expiratory maneuvers by flow-volume-diagrams increasingly succeeds in practical lung function diagnosis. Models for pressure-flow-volume relations during forced expiration basing these diagrams are presented. Indicators resulting by evaluation of the flow-volume-diagram are discussed in reference to their clinical relevance and to the parameters of the conventionally written volume-time-relation of the Tiffeneau-test.

Biophysical Phenomena↗
PubMed1980

[Long-term therapy with a peroral effective theophyllin compound (author's transl)].

The effects and side-effects of a long-term therapy with cholin theophyllinate (1200 mg/die) were observed in 20 patients with chronic partially reversible obstructive pulmonary diseases (10 asthmatics and 10 patients with bronchitis, most of them with greatly pronounced emphysema). The subjective tolerance of the medication as well as the effects on the pulmonary and cardiac functions were positive. The dosage of beta 2-mimetics and especially glucocorticoids could be reduced.

Adult↗
PubMed1979

[Measuring nasal resistance using passive anterior rhinomanometry. Results in normal subjects, bronchially hyperreactive and manifestly obstructed patients].

The values of nasal resistance measured by passive, anterior rhinomanometry are reported. The results of measurements on a group of healthy probands correlate significantly with those gained by wholebody-plethysmography. Three of four patients with bronchial hyperreactivity, on acetylcholine, had an increase of nasal resistance after endonasal application of this agents. Ten patients with 'COLD' had normal nasal resistance values; no increase of the values could be demonstrated, after local acetylcholine application.

Acetylcholine↗
PubMed1978

Is the rhesus protanomalous?

Comparison of rhesus, human trichromat, and human protanomalous subjects were made for measurements of spectral sensitivity involving Landolt ring acuity criteria from 0.11 to 1.11 min-1. At 0.11 min-1, rhesus spectral sensitivity was more similar to that of the normal human trichromats than that of the human protanomalous observers. However, as acuity criterion became finer (thereby involving more central retinal function), rhesus spectral sensitivity became markedly more similar to that of the human protanomalous observers than that of the normal human trichromats.

Adult↗
PubMed1978

Long-term changes in spectral sensitivity after low-level laser (514 nm) exposure.

Changes in rhesus spectral sensitivity were induced at low-level (2.1 log td) repetitive exposure to a visible (514 nm) coherent source. Irradiation involved the entire retina. Long-term suppression of intermediate cones was evident in spectral sensitivity functions measured for a very fine photopic (1.85 min-1) acuity criterion. At slightly coarser acuity criteria (1.42 min-1) but still photopic, evidence of rod intrusion was obtained. Recovery from these effects was not obtainable 14 months post-exposure. Possible morphological correlates at photoreceptor ultrastructural levels are discussed. Optical coherency is implicated in these effects.

Animals↗