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Biomedical subjects

W Lenz

Publications and source records attributed to W Lenz.

At least 91 records · Page 5Linked to original sources
PubMed1985

[Scanning and transmission electron microscopy findings in the coronary vessels in physiologic and pathologic states].

Scanning and transmission electron microscopic examinations of the coronary vessels were performed on rats, and the findings compared. Both procedures demonstrated a tightly meshed network of arterial endothelium orientated to the direction of flow, thereby allowing optimal adaptation to changes in direction of blood flow, high intervascular pressure, structures of the remaining intima components and variable states of arterial wall tension. Venous endothelium proved to possess a markedly less uniform constitution, the texture of the inner surfaces being strongly determined by the surrounding perivascular tissue. Induction of arterial hypertension in rats (via GOLDBLATT-hypertension) and in Cynomolgus monkeys (via aortic constriction), and hyperlipidemia in hypertensive rats through a fatty diet enabled the study of a wide spectrum of coronary artery endothelium disease, primarily at early stages. Both species demonstrated hypertensive endothelial dehiscence (gaps), basically passive in nature and due to increased endothelial mobility. Occasionally, peculiar cytoplasma deformations could be found surrounded by circumscribed, consecutive endothelial gaps, allowing speculation of increased contraction-like states of intraendothelial filament tension due to hypertension. Areas of intima damage were usually focal and demonstrated numerous degenerative endothelial changes, endothelium necrosis and defects. Small endothelial gaps were covered by a film of thombocytes, though this finding was seen only in monkeys. Attempts at endothelium regeneration and reparation were manifest in increased endothelial mitosis, pseudoendotheliums, endothelial giant cells and films of leucocyte aggregations covering endothelium defects. Migration of leucocytes into the intima was actively furthered through small leaks in the endothelium. Hyperlipidemic and hypertensive rats showed endothelial bloating, due in part to vacuolar intracytoplasmatic lipid deposits with phagocytosis of fine particles of cholesterin crystals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Incidence at birth of different types of limb reduction abnormalities in Hungary 1975-1977.

Congenital limb reduction abnormalities have been reported in Hungary since 1970. A clinical and genetic study was made of 274 cases reported from 1975 to 1977, corresponding to a total number of 561915 births. A classification according to type of defect, involvement of one or more limbs and other associated defects is attempted. Data on incidence, sex ratio, laterality and mortality are presented.

Abnormalities, Multiple↗
PubMed1983

Family study of congenital limb reduction abnormalities in Hungary 1975-1977.

A family study of 274 index patients with limb reduction malformations born in Hungary from 1975 to 1977 is reported. The majority of 789 first-degree relatives were personally examined. Information was collected on 1094 uncles and aunts and on 1095 cousins, and those affected by limb malformations were examined. Among 789 first-degree relatives six were affected by a similar malformation (radial, ulnar and central ray defects) and 1 by a malformation of a different type; no secondary cases of the same type were found among the relatives of patients with terminal transverse and amniogenic malformations, and with limb malformations which were part of syndromes or unclassifiable associations with other malformations. While a few rare types of limb defects are due to dominant genes, the aetiology of most cases is obscure. There is no evidence of sex-linked inheritance, of multifactorial causation or of environmental factors shared by relatives. These results are similar to those of an earlier study by Birch-Jensen.

Abnormalities, Multiple↗
PubMed1983

Enterotoxigenicity of Staphylococcus aureus strains from clinical isolates.

The enterotoxigenicity of 208 strains of Staphylococcus aureus isolated from clinical specimens and four strains isolated from food was investigated. All strains were examined for production of enterotoxins A, B, C, D, and E in cellophane-over-agar cultures using a modified optimum-sensitivity-plate method. Strains from systemic infections were also examined for production of toxic-shock toxin. The overall frequency of enterotoxigenic strains among the clinical isolates was 42%. Enterotoxin A was the predominant enterotoxin found among positive strains (45/88). Enterotoxins B to E were found in decreasing order of frequency. Twenty-three strains produced two enterotoxins and one strain three toxins. A significant association was observed between multi-resistance of strains (defined as resistance against penicillin and at least two other antibiotics) and enterotoxin B production. Strains from phage groups I and III produced predominantly enterotoxin A. Four of the five strains producing toxic shock toxin belonged to phage group I; one was not classifiable.

Bacteriophage Typing↗
PubMed1983

[Lymphographic and morphological studies of the conjunctiva in onchocerciasis patients in Liberia].

Conjunctival lymphographies in patients infected with Onchocerca volvulus in Liberia showed normal or only slightly dilated lymphatics. The light-microscopical studies of conjunctival specimens revealed microfilariae predominantly in edematous dilated interstitial channels. Microfilariae in lymphatics and interstitial channels without endothelium of the conjunctivae were demonstrated by scanning and transmission electron microscopy. No signs of inflammatory cellular reaction were found in the vicinity of the parasites. In conclusion, the dilatation of lymphatics and interstitial channels as well as the pathways along which the microfilarial penetrated the cornea and the anterior segments of the eye are discussed.

Conjunctiva↗
PubMed1983

[Demonstration of enterotoxin in Staphylococcus aureus cultures by the ELISA test and the microslide test].

340 S. aureus strains, isolated either from routine food test samples, or from food leftovers, from healthy or sick persons in cases of suspected food poisoning in various places of the Federal Republic of Germany, were tested for enterotoxin production. The enterotoxin types A, B and C (SEA, SEB and SEC) were determined both by the ELISA and the microslide test (MS-test), the enterotoxin types D and E by the MS-test only. Comparison of the two test methods clearly shows that the ELISA technique is superior to the MS method: The sensitivity of the ELISA was at 2.5 ng, whereas that of the MS-test was limited to approximately 1 microgram. The ELISA revealed 6.2% more of the strains as enterotoxin producers, and reproducibility of the test results was also better with the ELISA than with the MS-test. Furthermore, the ELISA is far more efficient, consuming less test reagents, and with a capacity for testing more strains in a shorter time procedure. The incidence rate of the various enterotoxin types, referred to one representative strain each per outbreak of food poisoning or group of persons investigated, is as follows: 45.3% SEA, 17.2% SEB, 23.4% SEC. The incidence rate of SED, SEE or SE-type combinations was less than 5%. In sick persons, SEA- and SEC-producing strains occurred within the same range, i.e. 34.8% and 30.4% respectively. SEA-producing S. aureus strains had the highest frequency in food samples (61.5%) and in healthy individuals (53.6%).

Enterotoxins↗