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Biomedical subjects

M Young

Publications and source records attributed to M Young.

At least 307 records · Page 17Linked to original sources
PubMed1987

Lung cancer mortality in workers exposed to sulfuric acid mist and other acid mists.

Mortality patterns were studied in 1,165 workers exposed to sulfuric acid mist and other acid mists (primarily hydrochloric acid mist) in steel-pickling operations. Standardized mortality ratio (SMR) analysis of the full "any acid exposure" cohort (n = 1,165), with the use of U.S. death rates as a standard, showed that lung cancer was significantly elevated, with a mortality ratio of 1.64 [95% confidence interval (CI) = 1.14-2.28, based on 35 observed deaths]. The lung cancer mortality ratio for workers exposed only to sulfuric acid (n = 722) was lower (SMR = 1.39), but further restriction to the time 20 years and more from first employment in a job with probable daily sulfuric acid exposure (approximately equal to 0.2 mg/m3) yielded a mortality ratio of 1.93 (95% CI = 1.10-3.13). An excess lung cancer risk was also seen in workers exposed to acids other than sulfuric acid (SMR = 2.24; 95% CI = 1.02-2.46). When comparison was made to other steel workers (rather than to the U.S. general population) to control for socioeconomic and life-style factors such as smoking, the largest lung cancer excess was again seen in workers exposed to acids other than sulfuric acid (SMR = 2.00; 95% CI = 1.06-3.78). Adjustment for potential differences in smoking habits showed that increased smoking was unlikely to have entirely explained the increased risk. Mortality from causes of death other than lung cancer was unremarkable, with the exception of significantly low rates for deaths due to digestive system diseases.

Adolescent↗
PubMed1987

Biomedical prevention of mental retardation. A model state plan.

A model state plan for prevention coordinates human, economic, and social resources in a thoughtful process of identification of causes and prevention of mental retardation and a systematic application of that knowledge through a variety of approaches. Systems approaches suggest that "everything is connected to everything else." In this connection, a program, by definition, should be a planned effort to approach various aspects of an identified major problem by means of a series of interrelated projects; a single, isolated, one-shot project is not a program. This definition of program connotes a sustained commitment consistent with planned social change in order to modify institutions to make them more responsive to community need (Goldston, 1977). A sustained commitment is the cornerstone of a model state plan for prevention. The meshing of effort and services demanded of comprehensive prevention planning requires the support of both the executive and legislative branches of government.

Child↗
PubMed1986

Nerve growth factor: biosynthetic products of the mouse salivary glands. Characterization of stable high molecular weight and 32,000-dalton nerve growth factors.

Nerve growth factor (NGF) is a protein required for the growth and development of sensory and sympathetic neurons. The NGF is present in high concentrations in male mouse salivary glands, bovine seminal plasma, and snake venom. The physiological significance of NGF in these sources is not known: it might be a part of a high molecular weight (HMW) protein with possibly different biological function and be cleaved to the functional size by proteases. In an attempt to isolate a HMW protein containing as part of its structure the low molecular weight (LMW) NGF (2.5S), mouse salivary glands were homogenized in the presence of either 8 M urea or 6 M guanidine hydrochloride (Gdn X HCl) in order to denature proteases. This procedure revealed that the LMW NGF is a part of two HMW proteins that are biologically and immunologically homologous to the mouse 2.5S NGF. One of these HMW proteins (Mr 32,000 NGF) was purified and shown to be biologically active in the NGF bioassay. Furthermore, this Mr 32,000 NGF was cleaved by the gamma subunit of mouse HMW NGF to the 2.5S NGF. Evidence is also presented that there may be a HMW protein(s) with apparent molecular weights ranging from 94,000 to 200,000 and immunologically homologous to the three subunits (alpha, beta, gamma) of 7S NGF. This HMW NGF is biologically active in the NGF bioassay, and its activity is inhibited by antibody to the beta subunit. Furthermore, in contrast to mouse 7S NGF, this HMW NGF does not dissociate in either 8 M urea or 6 M Gdn X HCl.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Structural and mechanistic studies on the HeLa and chicken liver proteins that catalyze glycinamide ribonucleotide synthesis and formylation and aminoimidazole ribonucleotide synthesis.

Glycinamide ribonucleotide (GAR) transformylase from HeLa cells has been purified 200-fold to apparent homogeneity with a procedure using two affinity resins. The activities glycinamide ribonucleotide synthetase and aminoimidazole ribonucleotide synthetase were found to copurify with GAR transformylase. Glycinamide ribonucleotide synthetase and GAR transformylase were separable only after exposure to chymotrypsin. Antibodies raised to pure L1210 cell GAR transformylase were able to precipitate the glycinamide ribonucleotide transformylase and GAR synthetase activities from HeLa and L1210 cells both in their native and in their proteolytically shortened forms. The compound N-10-(bromoacetyl)-5,8-dideazafolate was found to inhibit formylation but to leave the ATP-requiring synthetase activities intact.

Acyltransferases↗
PubMed1986

Characterization of human T cell-derived IgE-potentiating factor.

We have previously shown that Fc epsilon receptor-positive (Fc epsilon R+) T cell lines from patients with the hyper IgE syndrome secrete IgE-binding factors which selectively enhance IgE but not IgG synthesis in cultures of B cells obtained from patients with allergic rhinitis but not from nonatopic subject. In the present study we have tested the effect of supernatants from Fc epsilon R+ T cell lines on a large panel of B cells from atopic patients (n = 20). We found that IgE synthesis was selectively enhanced only in B cell cultures in which there was ongoing spontaneous synthesis of IgE. The target of IgE-potentiating factor(s) was a large low-density B cell present in the circulation of responding atopic donors. In addition, we further characterized IgE-potentiating factors derived from Fc epsilon R+ T cell lines. The factor(s) fractionated into 2 peaks on Sephadex G-75 with approximate molecular masses of 15,000 and 60,000 kDa, and had affinity for lentil lectin but not for peanut agglutinin. Release of IgE-potentiating factor(s) was enhanced by the addition of exogenous human IgE to Fc epsilon R+ T cell cultures and was inhibited by tunicamycin, an inhibitor of N-glycosylation. These studies suggest a close homology between the physicochemical characteristics of human and rodent IgE-potentiating factors and the immune signals which modulate production of these IgE regulatory factors.

B-Lymphocytes↗
PubMed1986

Effect of saturated phosphatidylcholines on the functional properties of reconstituted cytochrome oxidase.

Cytochrome oxidase was incorporated into liposomes, at various protein/lipid ratios, composed of either a phosphatidylcholine of varying chain length and symmetry or asolectin. Catalytic activity and respiratory control were assayed at two temperatures. All preparations showed higher activity at low protein/lipid ratios, but only asolectin showed respiratory control. A spectroscopic determination of the vectorial orientation of oxidase molecules showed that, for proteoliposomes with saturated lipids, 100% of oxidase molecules could be reduced by external substrate as compared with 75% for asolectin proteoliposomes. Freeze-fracture electron microscopy confirmed that oxidase was incorporated into these proteoliposomes and differential scanning calorimetry indicated that the protein induces significant disruption in the long range packing of the saturated phospholipids. We propose that the oxidase molecules in proteoliposomes formed from saturated phosphatidylcholines do not display respiratory control because they are unable to assume the transmembrane orientation necessary for full vectorial activity.

Animals↗
PubMed1986

Human regulatory T-cell subsets.

The immune response is under the regulation of T-cell populations that are characterized by defined cell surface markers. The differentiation and functional heterogeneity of these T-cell subsets are discussed in normal and disease states.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Dependence of subjective traverse length on velocity of moving tactile stimuli.

Two series of experiments were performed to assess the effects of stimulus velocity on human subjects' perception of the distance traversed by a moving tactile stimulus. In all experiments, constant-velocity stimuli were applied to the dorsal surface of the left forearm; velocities ranging between 1.0 and 256 cm/sec were used. In some experiments the stimuli moved from distal to proximal over the skin, and in others they moved from proximal to distal. The length of skin contacted by the moving stimulus was defined by a plate having an aperture of 4.0 X 0.5 cm. In the first series of experiments, subjects were required to compare the distance traversed by a test stimulus delivered 2 sec after a standard stimulus, and also to report the on-locus and the off-locus of the brushing stimulus. In the second series of experiments, the subjects rated the perceived distance on the skin using a free-magnitude-estimation procedure. The data from both series of experiments defined the same relationship between stimulus velocity and perceived stimulus distance. More specifically, although the length of skin contacted by the stimulus was the same at all velocities, subjects' estimates of stimulus distance decreased with increasing stimulus velocity. In addition, the function relating estimates of stimulus distance to velocity was flat for velocities between 5 and 20 cm/sec, but possessed an appreciable negative slope at lower and higher velocities. It is interesting that the plateau of the relationship between perceived stimulus distance and velocity occurred within the range of velocities that human subjects employ to scan textured surfaces; it also corresponded precisely with the range of stimulus velocities at which the directional sensitivity of somatosensory cortical neurons and human subjects is optimal.

Adult↗
PubMed1985

A multifunctional protein possessing glycinamide ribonucleotide synthetase, glycinamide ribonucleotide transformylase, and aminoimidazole ribonucleotide synthetase activities in de novo purine biosynthesis.

Three activities on the pathway of purine biosynthesis de novo in chicken liver, namely, glycinamide ribonucleotide synthetase, glycinamide ribonucleotide transformylase, and aminoimidazole ribonucleotide synthetase, have been found to reside on the same polypeptide chain. Three diverse purification schemes, utilizing three different affinity resins, give rise to the same protein since the final material has identical specific activities for all three enzymatic reactions and a molecular weight on sodium dodecyl sulfate gels of about 110 000. A single antibody preparation precipitates all three activities and binds to the multifunctional protein obtained by two methods in Western blots. Partial chymotryptic digestion of the purified protein gives rise to two fragments, one possessing glycinamide ribonucleotide synthetase activity and the other containing glycinamide ribonucleotide transformylase activity.

Acyltransferases↗
PubMed1985

Nerve growth factor. A structural relationship between its proteolytic and leukocyte-chemotactic active sites.

High molecular weight mouse nerve growth factor (HMW-NGF), in addition to its effects on certain neural elements, is also chemotactic for human polymorphonuclear leukocytes. One of the subunits of HMW-NGF is a protease of the serine family and its active site contains a serine residue and a closely-neighboring histidine residue that are both essential for proteolysis. Elimination of enzyme activity by irreversibly blocking the single serine has no effect on leukotaxis, but blocking the histidine abolishes leukotaxis. These results suggest the possibility that part of the proteolytic active site of this enzyme may have evolved to perform more than one, completely different, biologic function-proteolysis as well as nonproteolytically mediated chemotaxis.

Animals↗
PubMed1985

Nerve growth factor accelerates the early cellular events associated with wound healing.

The effects of injecting nerve growth factor (NGF) into subdermal air sacs on the backs of mice was studied. Sequential infiltration of cells into the lining of the sacs was observed. The initial cell type to infiltrate was the polymorphonuclear leukocyte, followed by highly vacuolated mononuclear cells, and then by fibroblast-like cells. This resembles the classical pattern of cellular responses during the normal process of wound healing. The kinetics for the peak accumulation of each cell type were dependent upon the concentration of NGF injected, and significant acceleration of infiltration of each cell type was observed with as little as 1 nM NGF. A similar acceleration of cellular infiltration was observed when mice were injected with the synthetic chemotactic peptide n-formyl-methionyl-leucyl-phenylalanine. This finding suggests that application of any chemotactic factor to wound sites may lead to accelerated tissue repair and an enhanced rate of wound contraction. The observation that NGF can act as a chemotactic factor in vivo may explain its ability to accelerate the healing of experimentally induced wounds in mice.

Animals↗
PubMed1985

Improving the practice of breast self-examination through assessment of alternative teaching formats.

College females (n = 186) in four different treatment groups completed questionnaires concerned with breast self-examination (BSE) at the beginning and end of a college semester. Analysis of data indicated that students who participated in small group instruction (which included modeling and guided practice) performed BSE more frequently and indicated greater confidence in their ability to perform the procedure than students in other groups. The results seem to indicate that the small group approach may be an effective supplement to regular classroom instruction.

Adult↗
PubMed1985

Nephrocalcinosis due to primary hyperoxaluria: case report from Saudi Arabia.

Two Arab siblings with nephrocalcinosis and renal failure secondary to primary hyperoxaluria are presented. Percutaneous renal biopsies obtained from both siblings showed marked oxalate deposition in the renal medulla. Primary hyperoxaluria should be considered in the differential diagnosis of renal failure in infancy and early childhood especially when evidence of obstructive uropathy is lacking.

Child, Preschool↗