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Biomedical subjects

D Fox

Publications and source records attributed to D Fox.

At least 91 records · Page 5Linked to original sources
PubMed1984

An alternative pathway of T-cell activation: a functional role for the 50 kd T11 sheep erythrocyte receptor protein.

A series of seven monoclonal antibodies was produced against the T-lineage-specific 50 kd T11 sheep erythrocyte rosette (SRBC) receptor protein in order to define the function of the molecule. Three distinct epitopes were detected: T11(1), the SRBC binding site expressed on all T lymphocytes and thymocytes; T11(2), an epitope unrelated to the SRBC binding site but with a similar distribution; and T11(3), a neo-epitope expressed only upon T-cell activation. Simultaneous triggering of T11(2) and T11(3) epitopes by monoclonal antibodies induces T lymphocytes to proliferate and mediate their functional programs in the absence of antigen and/or antigen-presenting cells. This antigen-independent mode of triggering is distinct from that involving the T3-Ti antigen receptor complex and represents an alternate pathway of T-cell activation. Given that T11 is the earliest T-lineage surface glycoprotein to appear in thymic ontogeny and is thus expressed before T3-Ti, the former may be involved in clonal expansion and/or differentiation during early development.

Animals↗
PubMed1982

R68.45 mediated chromosomal gene transfer in Agrobacterium tumefaciens.

A large plasmid enables its host Agrobacterium tumefaciens to cause tumorous condition in a wide variety of dicotyledonous plants[see Ooms et al. Gene 14:33--50 (1981) )). The location and role of chromosomal genes in this phenomenon are not known. As the first stage in studying this aspect, a project was initiated to investigate the chromosomal genetics of the bacterium. R68.45, a P group plasmid, was chosen as a transmission agent. After a preliminary assessment it was decided to use C58 as a standard strain to carry out the mapping. The plasmid itself, as judged by the presence of antibiotic markers, appears to be stable in A. tumefaciens; its ability to promote chromosomal mobilisation, however, remains only in 60--80% transconjugants. Good Agrobacterium donors are capable of transferring chromosomal genes at a frequency varying between 10(-5) to 10(-6) per recipient. The recombinants are stable even under non-selective conditions. A linear linkage map consisting of 16 markers was built using coinheritance frequencies obtained from 21 four-point crosses.

Chromosomes, Bacterial↗
PubMed1982

Identifying school children with behavior disorders.

Behavioral screening criteria were developed through the collaborative efforts of multidisciplinary professionals to enable teachers to identify school children with behavior disorders within the school setting. The criteria which were developed provide a step towards a practical means of implementing the legislative mandate of PL 94-142 in a medically and psychologically sound manner. An analysis of the criteria presented in the federal guidelines and working criteria proposed by experts in the field is presented. Increased liaison between professionals of all involved disciplines is encouraged for the identification, evaluation, treatment and placement of behavior disorder children. The background and process of developing the criteria is described.

Affective Symptoms↗
PubMed1980

X-linked mental retardation: Renpenning revisited.

Nine men with X-linked mental retardation (MR) belonging to the family originally described by Renpenning and his colleagues have been reexamined and restudied. None of these men have the fragile X chromosome, and none have macro-orchidism; their testes range in size from small to average. All but one are severely retarded; one has an IQ of 70, the mean IQ of the remainder is 30 with a range of 18 to 45. They are short in stature, have small or normal-size ears and lower jaws, and a moderate degree of microcephaly, the mean skull circumference being just below two standard deviations from the normal.

Female↗
PubMed1980

Pulmonary hypertension in systemic lupus erythematosus: hemodynamics and effects of vasodilator therapy.

A case is reported of a 29-year-old woman with systemic lupus erythematosus (SLE) who developed clinical manifestations of pulmonary hypertension at a time when other manifestations of SLE were quiescent. She had a restrictive ventilatory defect but clear lung fields on chest x ray. Cardiac catheterization revealed severe pulmonary hypertension. Calculated pulmonary vascular resistance fell slightly after administration of oxygen and during infusion of vasodilators. Symptomatic improvement and a modest increase in right ventricular ejection fraction, as measured by radionuclide ventriculography, were noted following 1 week of oral hydralazine therapy. Clinically significant pulmonary hypertension is a rare complication of SLE and the increased pulmonary vascular resistance may not be entirely fixed. Cardiac catheterization and radionuclide ventriculography may be useful in assessing response to medical therapy.

Adult↗
PubMed1979

Human hexosaminidase isozymes. IV. Effects of oral contraceptive steroids on serum hexosaminidase activity.

Data from a mass screening program for identification of persons who are heterozygous for Tay-Sachs disease have been analyzed for the effects of oral contraceptive steroids on the activity in serum of hexosaminidase (hex) and the various hex isozymes. Women using oral contraceptives show a significantly higher total serum hex activity, reflecting mainly an increase in the heat-stable hex isozyme (hex I), and a smaller increase in the heat-labile hex A than do women using no medications. The changes in women using oral contraceptives are qualitatively similar to those observed during pregnancy. The distribution of responses to oral contraceptives is unimodal, and some of the variations may be related to differences in amount of steroid ingested. In addition, underlying genetic variation may contribute to the observed differences in enzyme activities.

Adolescent↗
PubMed1978

Selected developmental factors of cleft palate children between two and thirty-three months of age.

The literature suggests that cleft palate children and adults perform below their peers on both linguistic and nonlinguistic tasks. The purpose of this investigation was to ascertain if developmental delay could be observed in 24 cleft palate children below the age of three years when compared to matched controls. Three developmental scales were administered to all infants, and complete medical histories and current weights were obtained. Results indicated that the performance of the cleft palate subjects paralleled but fell below their peers on all developmental subtests. The differences were significant (p is less than .05) on three language subtests and on one personal-social and one motor subtest. The mean percentile weight also differed significantly (p is less than .05). Multivariate analysis explored the relationship of 1) extent of cleft, 2) sex, 3) hearing loss, 4) length of hospitalization, and 5) weight to the developmental scores. The extent of the cleft proved to be significant.

Child Development↗
PubMed1978

Human hexosaminidase isozymes. III. Distribution and activity of isozymes in peripheral blood leukocytes and platelets.

The specific activity and distribution of the isozymes of hex have been studied in platelets, granulocytes, monocytes, and lymphocytes isolated from venous blood. Since there are considerable differences in the content of the various hexosaminidase isozymes in these cell types, the relative activity of the A isozyme, expressed as a percent of total hexosaminidase in a mixed leukocyte preparation, is dependent on the proportion of the individual cell types present in a sample of peripheral blood. Because of variation in the proportion of cell types, the results may not accurately reflect the genotype of the blood donor. In contrast, chromatographic separation and assay of platelet extracts for activity of hexosaminidase isozymes provides a most convenient and satisfactory method of discriminating carriers and noncarriers of the Tay-Sachs mutant gene. Moreover, the ease of isolating platelets and the smaller volume of blood required compared with methods for obtaining purified leukocyte preparations offer additional advantages for identification or verification of the Tay-Sachs heterozygote state.

Blood Platelets↗
PubMed1977

Autonomic neuropathy and painless myocardial infarction in diabetic patients. Histologic evidence of their relationship.

Myocardial infarction is considered the prime cause of death among adult diabetic patients. In a great number of cases, during myocardial infarction the patients don't feel pain or it is atypical. Diagnosis can be neglected, and mortality increases. In search of an explanation for the absence of pain in these patients, the authors studied the autonomic nerve fibers of the heart muscle with argentic and combined techniques, looking for lesions in the sympathetic or parasympathetic nerve fibers that conduct pain. In the five cases of painless myocardial infarction studied, the nerve fibers showed typical lesions of diabetic neuropathy: beaded thickenings, spindle-shaped thickenings, fragmentation of fibers, and diminution of the number of fibers in the nerves. The patients in the control group (five diabetics with painful infarction, five diabetics with infarction, five nondiabetics with painful infarction, and five nondiabetics without infarction) had no lesions. These facts led us to assume that the absence of pain in diabetics with myocardial infarction could be due to a lesion of the afferent nerves that conduct pain.

Adult↗