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Biomedical subjects

M Beck

Publications and source records attributed to M Beck.

At least 307 records · Page 17Linked to original sources
PubMed1985

Aversive and attractive marking of toxic and safe foods by Norway rats.

The present series of studies was undertaken to investigate the hypothesis (von F. Steiniger, 1950, Zeitschrift für Tierpsychologie, 7, 356-379; K. A. Stierhoff, & M. Lavin, 1982, Behavioral and Neural Biology, 34, 180-189) that rats poisoned after eating a novel food will mark that novel food in such a way as to dissuade naive conspecifics from ingesting it. Our results provided no evidence of aversive marking of a novel food by rats poisoned after ingesting it. We did, however, find evidence of attractive marking of feeding sites by rats exploiting those sites. This attractive marking rendered exploited feeding sites more attractive to naive conspecifics than other portions of an enclosure that rats had visited. The present findings are consistent with the results of a number of experiments conducted in our laboratory over the last decade indicating that rats directly communicate learned food preferences, but not learned food aversions.

Animals↗
PubMed1985

[Ocular findings in Barsy syndrome].

Report on a male newborn with progeroid aspect, cutis laxa, intrauterine growth retardation, bilateral dislocation of the hip, generalized anomalies of ossification, peripheral corneal opacification comparable to corneal senile arcus, a diffuse, very discrete clouding of the stroma and an anterior polar cataract OD. Diagnosis and differential diagnosis of other progeroid and cutis laxa syndromes are discussed on the basis of the corresponding ocular findings.

Corneal Opacity↗
PubMed1985

Immunity to herpes simplex virus: virus reactivation modulates lymphokine activity.

Cell-mediated immunity to herpes simplex virus (HSV) was studied in patients with recurrent disease and in seropositive controls. Supernatants from cultures of peripheral blood mononuclear cells (PBLs) obtained during recrudescence (zero to three days after onset of lesions), convalescence (four to 14 days), and quiescence (greater than 14 days) were assayed for their ability to augment natural killer activity of normal PBLs against K562 target cells. Supernatants obtained during recrudescence, but not those obtained during convalescence, quiescence, or from seropositive controls, failed to augment natural killer activity but contained interferon and interleukin-2. Dialysis restored the ability of the supernatants to augment natural killer activity, and herpesvirus [UV-HSV-2(G)] stimulation of recrudescent PBLs in the presence of 2 X 10(6) M indomethacin abrogated suppression of natural killer-enhancing activity. However, similar levels of prostaglandin E were observed in supernatants of PBLs collected throughout the disease cycle from individuals with recurrent disease or from seropositive controls. The data suggest that reactivation of latent HSV is associated with the induction of a dialyzable factor(s) that interferes with interferon or interleukin-2-mediated natural killer enhancement or both. Prostaglandin E is necessary but insufficient for suppression of natural killer-enhancing activity.

Adult↗
PubMed1984

Biosynthesis of proteodermatan sulfate in cultured human fibroblasts.

Biosynthesis and secretion of proteodermatan sulfate produced by cultured human skin fibroblasts were investigated employing immunological procedures. During an incubation period of 10 min in the presence of [3H]leucine, two core protein forms of Mr = 46,000 and 44,000, respectively, were synthesized. They were converted to mature proteodermatan sulfate with a half-time of approximately 12 min. Fifty per cent of total mature proteodermatan sulfate were found in the culture medium after a 35-min chase. Six to eight per cent remained associated with the cell layer after a chase of 6 h. In the presence of tunicamycin, fibroblasts synthesized a single core protein of Mr = 38,000 that was converted to mature proteodermatan sulfate and secreted with similar kinetics as the N-glycosylated species. Subtle differences in the molecular size of core proteins were noted when cell-associated and secreted proteodermatan sulfate were degraded with chondroitin ABC lyase, but core proteins free of N-linked oligosaccharides were identical. Labeling with [3H]mannose revealed that secreted proteodermatan sulfate contains two or three complex-type or two complex-type and one high-mannose-type N-linked oligosaccharide chains. The N-glycans are bound to a 21-kDa fragment of the core protein. After incubation in the presence of [3H]glucosamine, the [3H]galactosamine/[3H]glucosamine ratio was 3.76 and 3.30 for secreted and cell-associated proteodermatan sulfate, respectively. Evidence for the presence of O-linked oligosaccharides could not be obtained. Small amounts of core protein free of dermatan sulfate chains were secreted when the cultures were treated with p-nitrophenyl-beta-D-xyloside.

Acetylglucosaminidase↗
PubMed1984

Dyggve-Melchior-Clausen syndrome: normal degradation of proteodermatan sulfate, proteokeratan sulfate and heparan sulfate.

It had been suggested that Dyggve-Melchior-Clausen syndrome may be due to the deficiency of a specific sulfatase and/or a protease involved in proteoglycan degradation. The ability of Dyggve-Melchior-Clausen fibroblasts to endocytose and degrade 3H-leucine- and 35S-sulfate-labelled proteodermatan sulfate and 35S-sulfate-labelled proteokeratan sulfate, respectively, was therefore investigated. The turnover of cell-associated 35S-sulfate-labelled heparan sulfate was also followed. In all these experiments Dyggve-Melchior-Clausen fibroblasts behaved normally.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1984

Neuraminidase deficiency presenting as non-immune hydrops fetalis.

A newborn infant with oedema, ascites and hepatosplenomegaly is described. In ascites fluid foamy macrophages were found, in a liver biopsy cytoplasmic inclusions and membrane-bound vacuoles were seen. Furthermore the child excreted excessive amounts of sialic acid-rich oligosaccharides in the urine, and therefore a neurovisceral degenerative disorder was assumed. The diagnosis of sialidosis was confirmed by enzymatic assay in cultured fibroblasts, in which a complete deficiency of the lysosomal enzyme neuraminidase could be demonstrated. After recurrent septicaemias the child became dystrophic and died at the age of 6 months. Our case is compared with sialidosis observed by other authors, the wide phenotypic diversity within this biochemical defect is emphasised. The occurrence of hydrops fetalis in lysosomal storage diseases is discussed.

Edema↗
PubMed1984

Disc oedema in association with Hunter's syndrome: ocular histopathological findings.

The histopathology of the posterior half of one eye and the optic nerves of a man with Hunter's syndrome, who was known to have disc oedema without raised intracranial pressure for 11 years of his life, is reported. The possible pathogenesis of the disc oedema is discussed; an important contributory factor was the deposition of abnormal mucopolysaccharides within the sclera. This caused gross thickening of the sclera with compression of the optic nerve at the intrascleral level.

Adult↗
PubMed1984

Special calcium appetite in laying hens.

An experiment was conducted to study calcium appetite and dietary calcium level related to laying hen performance. The experiment consisted of three periods: pre-experimental, training, and experimental. A total of 80 commercial strain laying hens (58 weeks old) were divided into two groups. One group (20 birds) served as a control throughout the experiment and was fed 3.5% dietary calcium without a free-choice calcium supplement. The other 60 birds were randomly divided into 3 sets of 20 and were all fed 3.5% dietary calcium for a pre-experimental period (13 days) as an adaptation period to a new environment prior to a training period (5 weeks). Dietary calcium level was decreased by .5% each week through the 5th week (to 1% Ca) for all 60 hens during the training period. The birds were given access to a free-choice calcium supplement (calcium carbonate granules) during both the pre-experimental and training periods. This dietary regimen was used in an effort to allow all hens to adapt to a supplemental feeding program and be prepared or conditioned for sudden changes in dietary calcium level. At the end of the training period, the 3 sets of 20 hens were fed either 1, 3, or 5% dietary calcium and a free-choice calcium supplement for 6 weeks. As dietary calcium level was increased, there was a decrease in free-choice supplemental calcium intake; however, all birds (except controls) consumed very large amounts of calcium. The training procedure was successful: no hens rejected the supplement. Neither dietary calcium level nor total calcium intake affected feed intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Detection of an antigen on the inner surface of Rh negative erythrocytes which binds anti-D IgG.

Previous investigation have demonstrated the presence of the Rho(D) antigen in Rh negative erythrocytes. The intact Rh negative cell, however, does not bind anti-D IgG. Presently we have shown that an anti-D binding antigen resides on the cytoplasmic surface of Rh negative erythrocyte membranes. Unsealed Rh negative membranes, in which both the inner and outer surface are exposed, bind anti-D IgG. Dicyclohexylcarbodiimide specifically blocked the binding of anti-D IgG to these membranes. Sealed Rh negative membranes which expose only their external surface, failed to bind anti-D antiserum. These results were confirmed by proteolytic digestion of membrane preparations and subsequent Rho(D) antigen purification. Only when protease had access to the inner surface of Rh negative erythrocyte membranes did degradation of this 'D' antigen occur. Thus, intact Rh negative erythrocytes contain an antigen which binds anti-D antibody but is located on the inner surface of the membrane. In contrast, Rh positive erythrocytes expose Rho(D) antigen on the external surface of the membrane.

Antigens, Surface↗
PubMed1983

Oral promethazine hydrochloride in ethylenediamine-sensitive patients.

A study of 12 patients with allergic contact sensitivity to ethylenediamine has shown that exposure to the oral antihistamine promethazine hydrochloride (Phenergan) did not result in an exacerbation or recrudescence of eczema. This would suggest that promethazine may be safely administered to ethylenediamine-sensitive patients contrary to advice given in some of the dermatological literature.

Administration, Oral↗
PubMed1983

Abnormal proteodermatan sulfate in three patients with Coffin-Lowry syndrome.

The properties of [35S]sulfate-labeled proteoglycans secreted by normal human skin fibroblasts were compared with those synthesized by fibroblasts from three patients with Coffin-Lowry syndrome. 60-80% of secreted radioactive macromolecules from normal fibroblasts were eluted from a Sepharose CL-4B column with a mean Kav-value of 0.56 (pool 2); 3-10% of the radioactivity appeared in the exclusion volume of the column (pool 1). In contrast, 17-60% of the proteoglycans from the patients were found in the void volume. The bulk of remaining material was eluted with a mean Kav-value of 0.47. Pool 2 glycan chains from two patients exhibited an increased hydrodynamic size. Pool 1 from normal cells contained predominantly a glucuronic acid-rich proteodermatan sulfate, iduronic acid amounting for approximately 20% of glucuronic acid. In the respective proteodermatan sulfate from the patients, the relative iduronic acid content was at least 33% of that of glucuronic acid. Pool 2 material of all cell lines was characterized predominantly as iduronic acid-rich proteodermatan sulfate. In the proteoglycans from two patients the content of chondroitin 4-sulfate-derived disaccharides was increased at the expense of 6-sulfated chondroitin disaccharides. Native proteoglycans from the patients were less efficiently endocytosed by fibroblasts than their normal counterparts. Coffin-Lowry fibroblasts had a normal capability to synthesize glycosaminoglycan chains on an artificial acceptor, p-nitrophenyl-beta-D-xyloside. They were also normal in 3'-phosphoadenylylsulfate: chondroitin 4- and 6-sulfotransferase activities.

Abnormalities, Multiple↗