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Biomedical subjects

R D Snyder

Publications and source records attributed to R D Snyder.

At least 19 recordsLinked to original sources
PubMed1992

Effects of Captan on DNA and DNA metabolic processes in human diploid fibroblasts.

The fungicide Captan has been examined for its effects on DNA and DNA processing in order to better understand the genotoxicity associated with this agent. Captan treatment resulted in production of DNA single strand breaks and DNA-protein cross-links and elicited an excision repair response in human diploid fibroblasts. Captan was also shown to inhibit cellular DNA synthesis and to form stable adducts in herring sperm and human cellular DNA. Misincorporation of nucleotides into Captan-treated synthetic DNA templates was significantly elevated in an in vitro assay using E. coli DNA polymerase I, suggesting that DNA adduct formation by Captan could have mutagenic consequences. In sum, these studies demonstrate that Captan is capable of interacting with DNA at a number of levels and that these interactions could provide the basis for Captan's genotoxicity. The extreme cytotoxicity of this fungicide, however, could be due to other cellular effects since at the IC50 for cell killing, approximately 0.8 microM, none of the above genotoxic events could be detected by the methods employed.

Captan↗
PubMed1979

Infant botulism.

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Botulism↗
PubMed1979

Adenocarcinoma of unknown primary site: a clinico-pathological study.

An analysis of the clinico-pathological findings in 49 patients with adenocarcinoma of unknown primary origin indicates a short survival time. No factors were identified that influenced survival. Thromboembolic episodes and second primary tumors commonly complicate the clinical course. Metastases in widespread organs are common autopsy findings. Immunological mechanisms may explain these findings.

Abdominal Neoplasms↗
PubMed1979

Adrenoleukodystrophy and adrenomyeloneuropathy associated with partial adrenal insufficiency in three generations of a kindred.

Four cases of adrenoleukodystrophy (ALD) and one case of adrenomyeloneuropathy (AMN) have developed in a kindred over three generations demonstrating that AMN is a clinical variant of ALD. Pituitary-adrenal function studies were performed in 10 family members, including two affected males and four females identified as carriers of ALD/AMN. No pituitary-adrenal abnormality was found in the carriers. However, basal morning plasma adrenocorticotropic hormone (ACTH) levels were markedly elevated in the two males with ALD and AMN, despite the fact that they had no clinical signs of adrenal insufficiency and that morning plasma cortisol levels and their response to maximal exogenous ACTH stimulation appeared to be normal. In addition, the integrated 24-hour response to the administration were also subnormal in these two cases. Thus, people with ALD and AMN may have subclinical partial adrenocrotical insufficiency. No other endocrinologic dysfunction was identified.

Adolescent↗
PubMed1979

The right not to read.

Skill in reading is desirable. However, the importance of reading may be overemphasized in schools. Reading skills are determined relatively and not absolutely. Thus, relatively poor readers will persist. Schools cannot eradicate individual differences. Biological makeup and societal pressures are the important factors in determining reading skill. Present methods of reading remediation are of questionable efficacy and are traumatic to some children. Time with its associated normal development succeeds in remediating the majority of children with dyslexia. Most poor readers eventually attain reading levels that enable them to comprehend the types of printed materials commonly encountered. If a child finds reading difficult or distasteful, that child should be encouraged to read but should have the right not to be forced to read.

Achievement↗
PubMed1978

The follow-up CT scan in childhood meningitis.

CT in childhood bacterial meningitis has indicated that bacterial meningitis is more than an inflammation of the subarachnoid space; it is a disease process which often exerts a profound effect on the brain parenchyma. In some cases ventricular widening may be a reflection of loss of brain substance rather than increased intracranial pressure. A vasculitis may occur in cerebral vessels with consequent ischemic infarct. The abnormalities found on CT during the acute illness are frequently persistent.

Age Factors↗
PubMed1978

Fucosidosis.

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Adolescent↗
PubMed1978

Corticosteroids for asthma during pregnancy.

This is a retrospective evaluation of 36 pregnant patients who required corticosteroids for control of their asthma. In view of the lack of maternal or infant abnormalities it is felt that corticosteroids should not be withheld from pregnant patients when required.

Asthma↗
PubMed1977

Histiocytic lymphoma in the brain as the only manifestation of relapse following remission maintainance with BCG immunotherapy.

This report describes an unusual case of lymphoma which, after 54 months of complete remission induced with chemotherapy and maintained with BCG immunotherapy, relapsed in the brain alone. It is possible that the immunotherapy led to this pattern of relapse: this is supported by several other studies. The difficulty in diagnosing brain lymphoma is emphasized.

BCG Vaccine↗
PubMed1977

Fucosidosis.

Disseminated angiokeratomas can be seen in patients with an inherited deficiency of alpha-l-fucosidase as well as in patients with classic Fabry's disease. Patients with deficiency of this lysosomal enzyme, or fucosidosis, have spasticity, mental retardation, and retardation of growth in addition to angiokeratomas. We herein report three new cases of this rare syndrome.

Adolescent↗
PubMed1977

Fucosidosis with angiokeratoma. Electron microscopic changes in the skin.

An electron microscopic investigation was performed on the skin from three patients suffering from fucosidosis accompanied by diffuse angiokeratoma. Storage of fucose containing substances was represented by the following two kinds of cytosomes: lamellated bodies, found in Schwann cells and myoepithelial cells of sweat glands and membrane-bound vacuoles, located in various other cellular elements of the skin. Storage in endothelial cells caused narrowing or occlusion of some dermal blood vessels; in the papillary plexus, angiectasis was the result. Extensive vacuolation of the secretory cells of sweat glands could account for hypohydrosis. The characteristic distribution of cytosomes in various kinds of cells is helpful in differentiating fucosidosis from some other storage diseases on the basis of skin biopsy.

Adolescent↗
PubMed1976

Methylmercury poisoning, Clinical follow-up and sensory nerve conduction studies.

Methylmercury poisoning occurred in four cases after passage of methylmercury through the food chain. The neurological damage in all four cases was severe. The damage was greater at younger ages with maximum involvement in the case of transplacental poisoning. Significant recovery occurred in two cases, but on six-year follow-up two cases remained severely impaired. Clinical and electrophysiological evidence suggests that damage to peripheral sensory nerves may not be the cause of the late sensory symptomatology.

Adolescent↗