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Biomedical subjects

D Watkins

Publications and source records attributed to D Watkins.

At least 55 records · Page 3Linked to original sources
PubMed1994

Giant extra-adrenal myelolipoma.

Myelolipomas are rare, benign tumors composed in varying proportions of adipose tissue and hematopoietic cells. Myelolipomas are typically found in the adrenal gland, but uncommon cases of extra-adrenal sites have been reported, primarily presacrally. Extra-adrenal myelolipomas must be distinguished from masses of extramedullary hematopoiesis, which are also composed of hematopoietic elements but are associated with anemia and marked bone marrow hyperplasia. Also, if the distinction between extra-adrenal myelolipomas and malignant tumors such as liposarcoma were made before surgery, an invasive procedure might be avoided. We report the case of an extremely large, asymptomatic, perirenal myelolipoma in a 66-year-old diabetic woman. We also review the literature on extra-adrenal myelolipomas.

Aged↗
PubMed1993

Gender differences in the source and level of self-esteem of Chinese college students.

This research examined possible gender differences in the source and level of self-esteem of 99 male and 90 female undergraduates from mainland and China. There was little evidence of a gender difference in the level of overall self-esteem, but gender differences were evident in the subjects' ratings of the importance to their self-concept and their self-satisfaction with lower order facets of the self, indicating the necessity for using multidimensional measures of the self and for preserving the self-concept/self-esteem distinction.

Adult↗
PubMed1992

Oncogenes and glial tumors.

Results of numerous studies indicate that both activation of dominant oncogenes and inactivation of tumor suppressor genes play important roles in the genesis and progression of human gliomas. Activation of the epidermal growth factor receptor (erbB1 oncogene) as the result of gene amplification or rearrangement is the best established example of a dominant oncogene involved in glioma development. There is also suggestive evidence for activation of the ros oncogene in gliomas, and activation of a variety of other dominant oncogenes may be operative in individual tumors. Deletion studies suggest that inactivation of tumor suppressor genes on chromosomes 17p (probably the p53 gene), 10, 9p and 22 also play roles in genesis and progression of human gliomas. Additional work remains to be done to identify other dominant oncogenes and tumor suppressor genes involved in gliomas, and to determine how these various factors interact to cause disease.

Brain Neoplasms↗
PubMed1991

Panniculitis in an immunocompromised patient.

We present a patient in whom histoplasmosis panniculitis developed during steroid therapy for pancytopenia secondary to myelodysplasia. Although the cutaneous manifestations of disseminated histoplasmosis are rare, we review them because of the increasing numbers of organ-transplant patients, as well as other patients with immunodeficiency, including acquired immune deficiency syndrome, in whom the risk of this unusual presentation of histoplasmosis must be considered.

Aged↗
PubMed1991

Generation and analysis of clonal IgM- and IgG-producing human B cell lines expressing an anti-DNA-associated idiotype.

This study describes a methodology for generating stable, cloned, EBV-transformed IgG- and IgM-producing human B cell lines. Using these lines we have characterized immunoglobulin V gene utilization in an anti-DNA-associated idiotypic system. The 31 anti-DNA-associated idiotype is encoded preferentially by the VK1 gene family, and, in all probability, reflects a germ line gene-encoded framework determinant. Analysis of these lines indicates that the DNA-binding antibodies produced by B cell lines from SLE patients may differ from DNA binding myeloma proteins and from natural autoantibodies.

Antibodies, Antinuclear↗
PubMed1990

Methylmalonic aciduria due to a new defect in adenosylcobalamin accumulation by cells.

A child with methylmalonic aciduria due to failure to accumulate adocbl in mitochondria has a phenotype similar to cblA disease. Deficient utilization of labeled propionate by his fibroblasts is corrected by their fusion with those from cblA patients, indicating that he belongs to a different complementation class and probably is deficient in a different gene product. The defect appears not to be due to reduced affinity of enzymes for adocbl, or for ATP, and the minimal thiol required for adocbl synthesis is not different from that of extracts of normal cells.

Amino Acid Metabolism, Inborn Errors↗
PubMed1990

Effect of sulfhydryl reagents on pancreatic islet secretion granule-plasma membrane interaction.

To determine what role, if any, sulfhydryl groups may play in the fusion of islet secretion granules with the plasma membrane that takes place during exocytosis, we have studied the effect of several sulfhydryl-binding reagents, reducing agents, and oxidizing agents on the binding of 125I-labeled inside-out plasma membrane vesicles to isolated secretion granules. Three sulfhydryl-binding reagents, p-hydroxymercuribenzoate, Hg++, and N-ethyl maleimide, stimulated this binding, and the stimulation was greater in the absence of Ca++ than in its presence. In contrast, the three reducing agents used, glutathione, cysteine, and sodium bisulfite, inhibited the binding. Of the oxidizing agents, oxidized glutathione inhibited binding, whereas menadione and o-iodosobenzoate stimulated. The actions of Hg++ and glutathione were found to be on the secretion granules rather than the plasma membrane vesicles. It is concluded that the presence of a preponderance of sulfhydryl groups on the secretion granule membranes tends to limit their interaction with the plasma membrane and that these must be removed or masked for maximum fusion to occur.

Animals↗
PubMed1990

Exclusion of COL2A1 as a candidate gene in a family with Wagner-Stickler syndrome.

A large family with Wagner's vitreoretinal degeneration but none of the non-ocular features of Stickler's syndrome has been studied with gene probes for type II collagen. Recombination has been observed, thus excluding type II collagen as the site of mutation in this family. This report supports other published evidence that the Wagner-Stickler syndrome is genetically heterogeneous.

Bone Diseases, Developmental↗
PubMed1989

The strange tale of Martin van Butchell.

In the eighteenth century, a pedestrian strolling around Georgian London may have witnessed the bizarre sight of an ageing gentleman parading the streets on a painted horse and brandishing the jawbone of an ass. Not only was this man an eccentric, he was also a dentist. David Watkins here relates the remarkable story of Martin van Butchell, a dentist extraordinaire.

England↗
PubMed1989

An alternative to termination of pregnancy.

Few women choose to continue a pregnancy in which the foetus is not viable. However, the decision to terminate such a pregnancy may be more traumatic for some women and their partners than allowing nature to take its course.

Delivery, Obstetric↗
PubMed1989

Defective lysosomal release of vitamin B12 (cb1F): a hereditary cobalamin metabolic disorder associated with sudden death.

Here we report on a girl who presented with failure to thrive, developmental delay, minor facial anomalies, stomatitis, skin rashes, macrocytosis, mild homocystinemia(uria), and methylmalonic acidemia(uria). Fibroblast studies showed abnormal intracellular cobalamin (vitamin B12) metabolism. Reduced incorporation of 14C from [14C] propionate and [14C] methyltetrahydrofolate into TCA-precipitable macromolecules reflected decreased synthesis of adenosylcobalamin and methylcobalamin respectively. The diagnosis of cb1F mutation was established by demonstrating the accumulation of unmetabolized free cyanocobalamin in fibroblasts and by lack of genetic complementation with fibroblasts from the only other known cb1F patient. The defect is in the lysosomal release of endocytosed cobalamin. Administration of hydroxocobalamin resulted in clinical and biochemical improvement but sudden death occurred at age 5 months. The absence of brain pathological changes suggests that early treatment may prevent the neurological complications in cobalamin cofactor deficiency.

Female↗
PubMed1989

Functional methionine synthase deficiency (cblE and cblG): clinical and biochemical heterogeneity.

Functional methionine synthase deficiency is generally characterized by homocystinuria and hypomethioninemia in the absence of methylmalonic aciduria. Patients are divided into two classes, cblE and cblG, on the basis of complementation analysis. Presentation has usually been in the first 2 years of life, but one patient came to medical attention at age 21 years with symptoms initially diagnosed as multiple sclerosis. Common findings among 11 patients (4 with cblE and 7 with cblG) have included megaloblastic anemia (all patients) and various neurological deficits including developmental retardation (10 patients), cerebral atrophy (8 patients), hypotonia (7 patients), EEG abnormalities (6 patients), and nystagmus (5 patients). Hypertonia, seizures, blindness, and ataxia were less frequent. All patients have responded to therapy with cobalamin with resolution of anemia and biochemical abnormalities; neurological deficits resolved more slowly and in some cases incompletely. Hydroxycobalamin has been more effective than cyanocobalamin. Fibroblasts from patients with cblE (5 patients) and cblG (6 patients) all showed decreased intracellular levels of methylcobalamin (MeCbl) and decreased incorporation of label from 5-methyltetrahydrofolate into macromolecules, suggesting decreased activity of the MeCbl-dependent enzyme methionine synthase. Methionine synthase specific activity in extracts of all cblE fibroblasts was normal or near-normal under standard reducing conditions; synthase specific activity in extracts of 5 cblG patients was low but was high in a 6th patient measured in another laboratory. Thus, there is heterogeneity among patients with functional methionine synthase deficiency both in clinical presentation and in the results of biochemical studies of cultured cells.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1988

A simple method for measurement of left ventricular septal-lateral dimension.

In studies of myocardial performance of the intact heart, continuous measurement of the left ventricular septal-lateral diameter provides useful information. We describe a technique for placing a piezoelectric diameter gauge on the left ventricular endocardium of the intraventricular septum. This technique is simple and relatively atraumatic. It provides a way to evaluate septal-lateral dimension in either acute or chronic experiments and produces a stable signal that represents the instantaneous septal-lateral dimension of the left ventricle.

Animals↗