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Biomedical subjects

W Kern

Publications and source records attributed to W Kern.

At least 163 records · Page 9Linked to original sources
PubMed1987

Aerococcus bacteremia associated with granulocytopenia.

Two cases of bacteremic infection due to aerococci in granulocytopenic patients with acute leukemia and oral mucositis are described. Strains isolated from blood cultures of both patients were resistant to the antibiotics given orally for prophylaxis. One patient died in septic shock; surveillance cultures from oral washings in the other repeatedly showed high concentrations of aerococci. Aerococci were also isolated from surveillance cultures taken from 5 of 17 other patients with acute leukemia; however, their viable counts were lower than in the surviving patient.

Adult↗
PubMed1987

Experimental carotenoid retinopathy. II. Functional and morphological alterations of the rabbit retina after acute canthaxanthin application with small unilamellar phospholipid liposomes.

Eight "chinchilla bastard" pigmented rabbits were treated intravenously with sonicated phospholipid liposomes (SUV) consisting predominantly of egg yolk phosphatidylcholine (PC). Four rabbits were treated with canthaxanthin incorporated into PC liposomes in a single injection and fractionated over a period of 19 days. The total amount of PC used was a single dose of 260 mg administered as a 50-ml suspension and 13.7 mg/fraction given as a 5-ml suspension. The total amount of canthaxanthin used was a single 40 mg as a 50-ml suspension and 2.1 mg/fraction as 5-ml suspension. Electroretinography showed that canthaxanthin produced a depression of the a-waves and prolongation of the scotopic a- and b-wave peak latencies. A single high-dose injection of PC and PC plus canthaxanthin resulted in a transitory reduction in ERG amplitudes. A single injection of PC and canthaxanthin also produced hypernormal a-waves within the recovery time. Electron microscopy demonstrated that in contrast to the controls (PC), the canthaxanthin-treated rabbits showed alterations in the RPE/photoreceptor complex, indicating that these layers are the primary site of canthaxanthin effects on the retina.

Animals↗
PubMed1987

Experimental carotenoid retinopathy. I. Functional and morphological alterations of the rabbit retina after 11 months dietary carotenoid application.

beta-Carotene, canthaxanthin, and beta-carotene plus canthaxanthin were administered to "chinchilla bastard" pigmented rabbits in their rabbit diet (approximately 200 ppm carotenoid per group). The effect of the carotenoids on retinal function and morphology was tested against a control group in the course of 11 months. Electroretinography showed that in contrast to the control animals, beta-carotene-treated rabbits produced increasing peak latencies of the scotopic b-waves. In the canthaxanthin-treated rabbits, a- and b-waves showed hypernormal amplitudes at low cumulative dosages (approximately 0.5-2 g) and reduced amplitudes at higher dosages (about 5 g). The peak latencies of the scotopic a- and b-waves increased remarkably. This effect was still stronger in the carotenoid combination. Histology and electron microscopy indicated that in contrast to the control animals, canthaxanthin-treated rabbits showed a reduction in retinal thickness in some samples. In particular, they exhibited alterations in the granular layers and a marked diminuation of the photoreceptor outer segments and morphological alterations of the photoreceptor inner segments with massive deposition of electron-dense material. In all animals treated with carotenoids, lipid droplets of the retinal pigment epithelium were enlarged in size and number.

Animals↗
PubMed1987

[Endocarditis caused by Haemophilus parainfluenzae and Neisseria gonorrhoeae].

Infective endocarditis due to gramnegative bacteria is rare. Overall, its relative frequency seems to be much lower than 10 percent. According to the extensive literature reviewed most often the causative microorganisms belong to the families of enterobacteriaceae and pseudomonads. Extremely rare, however, are cases where certain fastidious gramnegative bacteria such as hemophili, neisseria and others are the causative organisms. We report two cases of infective endocarditis due to Haemophilus parainfluenzae and to Neisseria gonorrhoeae. Despite their fastidious growth, both organisms could rapidly be isolated from venous blood cultures. Both were sensitive to ampicillin or penicillin respectively, and adequate antimicrobial therapy could early be initiated. As compared to reports in the literature both cases showed typical valve involvement and took a relatively typical course under medical treatment. The Haemophilus parainfluenzae endocarditis presented as a subacute illness following a tooth extraction and showed large vegetations on a prolapsed mitral valve. In contrast to the findings of others signs of slight renal involvement but no signs of major arterial embolization were noted. Medical treatment with ampicillin plus an aminoglycoside was effective as in most other reported cases. Vegetations were echocardiographically no longer seen after five weeks. The gonococcal endocarditis early led to destructive lesions of the aortic valve, significant regurgitation, vascular congestion and complicating pneumonia. Medical treatment alone was not effective despite the high susceptibility to antibiotics ot the strain isolated. As reported für the majority of cases reviewed in the literature early valve replacement became necessary for a favourable outcome.

Adult↗
PubMed1986

The lenticular capsule and cellular migration in anterior capsular cataract.

A light and electron-microscopical study was performed on six lenses harboring anterior capsular cataract. The cataracts are typically divided by numerous sheets of basement membranes that merge with the lenticular capsule at the edge of the cataract. Basally, the cataract may or may not be bounded by a basement membrane. Myofibroblastlike cells may be observed, apparently traversing the basal border of the capsular cataract. Within the substance of the lens, isolated aggregations of collagenous material are present. Degenerating cells or collagenous aggregations are situated within the lenticular capsule. It is suggested that this configuration arises through the merging of basement membrane systems, surrounding the cells within the cataract, with the lenticular capsule.

Adult↗
PubMed1986

Night-time plasma cortisol secretion is associated with specific sleep stages.

Polysomnographic recordings were obtained in 16 healthy male subjects in order to evaluate temporal interrelationships between concentrations of plasma cortisol and sleep at night. The pattern of nocturnal cortisol secretion appeared to be synchronized with the periodicity of sleep: rapid eye movement (REM) sleep was found to be primarily present when cortisol concentrations were decreasing, indicating a diminished or absent secretory activity of the adrenals at that time; wakefulness and Stage 1 sleep, by contrast, were associated with increasing plasma cortisol concentrations. Furthermore, the enhanced adrenal secretory activity usually preceded the occurrence of light sleep or wakefulness, which is in accord with a wakening effect of plasma cortisol. Just prior to the onset of the first pronounced rise in plasma cortisol during sleep, episodes of slow wave sleep (SWS) became more frequent. This suggests that the offset of episodes of SWS may act as a trigger for the first pronounced nocturnal rise in plasma cortisol.

Adrenal Cortex↗
PubMed1986

Influences of corticosteroids, dexamethasone and hydrocortisone on sleep in humans.

The present two experiments were designed to investigate the effects of a synthetic and of a natural corticosteroid on nocturnal sleep in humans. Both experiments were held double-blind and designed according to a within-subject cross-over comparison. In the first experiment, 1 mg of dexamethasone applied orally prior to sleep (11.00 p.m.) led to a reduction of the percent of time spent in REM and in stage 4 sleep. The amount of stage 2 sleep tended to be increased after dexamethasone. In the second experiment, an infusion of 100 mg hydrocortisone throughout the night also reduced REM, but increased stage 4 sleep. A statistical comparison of both experiments suggested that both steroids not only reduced REM sleep but also tended to enhance intermittent wakefulness. This analysis also confirmed opposite effects on measures of slow-wave sleep of both substances. The results represent a first demonstration of differential effects of synthetic and natural corticosteroids on sleep, which has to be substantiated in further studies directly comparing effects of these steroids.

Adult↗
PubMed1978

The clinical course and treatment results of patients with postresection locally recurrent lung cancer.

Of 1018 patients with lung cancer seen in the division of radiation therapy between 1963 and 1976, forty-six patients (4.5%) presented with postresection local recurrence and no documented distant metastasis. The median time to recurrence was thirteen months. Most patients had central recurrence with hilar or mediastinal lymph node metastasis, parenchymal consolidation, main stem nodule or bronchial stump tumor. There was a propensity for these tumors to remain limited to the site of origin. Death was most often from local/regional disease rather than distant metastasis. In this clinical setting the effectiveness of radiotherapy was observed in terms of palliation and improved survival. Strong determinants to survival were cell type, tumor dose and tumor response. The median survival was eleven months.

Adenocarcinoma↗
PubMed1976

Lymphangitic carcinomatosis: lung scan abnormalities.

Lymphangitic carcinomatosis of the lung is a late and fatal manifestation of cancer. The diagnosis is seldom made ante mortem. Four patients with breast cancer had autopsy-proven lymphangitic metastases of the lung. Of these patients, two had normal chest x-rays and three had normal ventilation lung scans. The perfusion lung scans of all four showed irregular peripheral perfusion defects. Autopsies showed permeation of the lymphatics by tumor and tumor emboli in small arteries and arterioles.

Adult↗