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Biomedical subjects

B M Scher

Publications and source records attributed to B M Scher.

24 records · Page 2Linked to original sources
PubMed1978

Polymorphous presentations in vitelliform macular dystrophy: subretinal neovascularisation and central choroidal atrophy.

Two dominantly inherited macular dystrophies demonstrate the difficulty in establishing a diagnosis based on the fundus appearance. In 1 family the propositus presented with unilateral retinal haemorrhage associated with subretinal choroidal neovascularisation which remained unilateral over an 8-year period. In the other family the propositus presented with bilateral central choroidal atrophy. All affected family members had an abnormal electro-oculogram and a normal electroretinogram, suggesting the diagnosis of vitelliform macular dystrophy. Since vitelliform macular dystrophy has a wide range of expressivity, with polymorphous appearances of the fundus, the diagnosis is best made by the presence of a dominant mode of inheritance and an abnormal electro-oculogram.

Adult↗
PubMed1977

Macular colobomas in Leber's congenital amaurosis.

Two siblings with Leber's congenital amaurosis had the unusual association of bilateral macular colobomas. In addition to the colobomas, the patients also had deafmutism, severe myopia, large corneas, and an unusual discrete area of peripapillary tapetoretinal sheen. Electrodiagnostic evaluation of patients with congenitally poor visual ascuity and a central retinal defect differentiated a localized loss of funciton from a degeneration involving the entire retina.

Adult↗
PubMed1977

Fragmentation of Bacillus bacteriophage phi105 DNA by complementary single-stranded DNA in the cohesive ends of the molecule.

The structure of DNA from the temperate Bacillus subtilis phage phi105 was examined by using the restriction endonuclease EcoRI and by sedimentation analysis. The DNA contains six EcoRI cleavage sites. Although eight DNA fragments were identified in the EcoRI digests, the largest of these was shown to consist of the two fragments that carry the cohesive ends of the phage DNA. In neutral gradients, the majority of whole phi105 DNA sedimented as nicked circles and the remainder as oligomers. No unit-length linear structures were detected. The associated cohesive ends could be sealed by DNA ligase from Escherichia coli and could be cleaved by S1 nuclease. On the basis of these results and previously reported studies, it appears that, as isolated from phage particles, phi105 DNA is a circular molecule that is formed from the linear structure by the association of complementary single-stranded DNA.

Bacillus subtilis↗
PubMedDate not supplied

Benzyl alcohol alters the hemoglobin phenotype of mouse erythroleukemia cells.

The hemoglobin minor/hemoglobin major ratio expressed in mouse erythroleukemia (MEL) cells grown in vitro varies according to the differentiation inducer utilized. For example, butyrate and hemin induce higher hemoglobin minor/hemoglobin major ratios than do dimethyl sulfoxide (DMSO) or hexamethylene bisacetamide (HMBA). Benzyl alcohol in non-toxic concentrations was found to markedly reduce the hemoglobin minor/hemoglobin major ratio and to moderately reduce the total hemoglobin induced by DMSO or HMBA in MEL cells, while only slightly decreasing the ratio induced by hemin or butyrate. The addition of dexamethasone (another and more potent inhibitor of the induction of hemoglobin synthesis than benzyl alcohol) to the media during HMBA induction of differentiation increased the hemoglobin minor/hemoglobin major ratio. This is similar to other "inhibitory" treatments (i.e., treatments that result in sub-optimal hemoglobin production) that have been previously reported. Therefore, although benzyl alcohol and dexamethasone both partly inhibit the induction of total hemoglobin production, they have opposite effects on the induced hemoglobin phenotype: benzyl alcohol decreases the hemoglobin minor/hemoglobin major ratio while dexamethasone increases it. The mechanism(s) of the alteration in the hemoglobin phenotype is unknown as is the mechanism of induction by any of the various inducing agents or of the inhibition of induction by any treatment. However, it appears that if the signal for the induction of hemoglobin minor is sufficiently potent (as it is during butyrate or hemin induction), it cannot be overcome by benzyl alcohol at a "non-toxic" concentration.

Acetamides↗