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Biomedical subjects

D Wallace

Publications and source records attributed to D Wallace.

At least 91 records · Page 5Linked to original sources
PubMed1996

Fatal work-related injuries in the U.S. chemical industry 1984-89.

Several mortality studies of the chemical industry have examined fatal injuries, but most of these studies have been of employees of large chemical firms and have not separated work-related from non-work-related injuries. We examined all U.S. Occupational Safety and Health Administration (OSHA) investigation files in 1984-89 in 47 U.S. states of fatal injuries in the chemical industry, Standard Industrial Classification (SIC) 2800-2899. OSHA investigates all reported deaths over which it has jurisdiction; this includes most causes of work-related death except for homicide and motor vehicle crashes. For the 6 year period, there were 234 fatalities in the chemical industry, for a work-related fatality rate of 0.55 per 10,000 workers/year. The largest category of deaths was from explosions, with 99 (42%), followed by fire & burns, with 32 (14%), poisoning, with 31 (13%), and falls, with 18 (8%). Of the 99 deaths from explosions, 45 (45%) involved manufacture or handling of fireworks or other explosives. The fatality rate at firms with fewer than 50 employees was more than twice that of larger firms (P < 0.05) and employees at small firms were less likely to have been covered by a union contract (P < 0.05). OSHA issued citations for safety violations in 73% of the deaths. While regulatory authorities and the media often focus attention on large, multinational chemical corporations, the highest worker fatality rates are found at the smallest chemical firms.

Accidental Falls↗
PubMed1996

Insulin resistance associated with maternally inherited diabetes and deafness.

Maternally inherited diabetes and deafness (MIDD) is a form of diabetes associated with mutation of mitochondrial DNA (mtDNA) that occurs in 1% to 2% of individuals with diabetes. Understanding the clinical course and abnormalities in insulin secretion and action in affected individuals should allow better understanding of how this genetic defect alter glucose metabolism. We report the clinical course of three individuals with mtDNA mutations and deafness. Subjects no. 1 and 2 had diabetes not yet requiring insulin therapy, and subject no. 3, the son of subject no. 2, had normal glucose tolerance. Defective oxidative phosphorylation (OXPHOS) based on OXPHOS enzymology of skeletal muscle biopsy of subjects no. 1 and 2 showed activity of less than 5% of the tolerance level in complex III for subject no. 1 and in complexes I, I + III, and IV for subject no. 2. Assessing insulin secretion using insulin response to intravenous glucose and insulin sensitivity based on minimal model analysis of an insulin-modified frequently sampled intravenous glucose tolerance test (FSIGT), first-phase insulin secretion was abnormal in subjects no. 1 and 2 and normal in subject no. 3 (AUC, 57, 93, and 1,235 pmol/L, respectively). In contrast, all three subjects had low insulin sensitivity indices (0.04, 0.14, and 0.27 x 10-4 x min/pmol/L, respectively). Subject no. 2, who underwent three FSIGT studies over a 16-month interval, showed transient improvement in insulin release in response to modification of diet and exercise (first-phase insulin AUC, 57 pmol/min v 287 pmol/min 10 months later; fasting insulin, 97 pmol/L v 237 pmol/L 10 months later), but by 16 months, first-phase insulin release and fasting insulin had decreased (AUC, 64 and 136 pmol/L, respectively) despite higher fasting glucose. We conclude that in our subjects with MIDD, insulin resistance is present and appears to precede defects in insulin release.

Adolescent↗
PubMed1996

Prenatal diagnosis of a chest wall hamartoma and sternal cleft.

We present the prenatal evaluation and diagnosis of a disorganized chest wall hamartoma with underlying sternal cleft in a family with a prior offspring with the VATER association. The possibility that these conditions are linked to mesodermal defects with a common pathogenic etiology is suggested.

Adult↗
PubMed1996

Changes in the intracellular free amino acid pool in human saphenous vein tissue culture.

The aim of this work was to investigate the effect of tissue culture on the intracellular amino acid pool in both freshly isolated and surgically prepared saphenous vein segments taken from patients undergoing coronary artery bypass surgery (number of patients, n = 8). Viability of freshly isolated vein rings, indicated by ATP concentration, was maintained in culture (321 +/- 41 vs. 277 +/- 31 nmol (g wet wt)-1, 0 vs. 14 days). The initial decrease in ATP concentration in surgically prepared rings was significantly reversed following 14 days in culture from 135 +/- 26 to 201 +/- 18 nmol (g wet wt)-1 (P < 0.05). Freshly isolated vein rings maintained their intracellular free amino acid pool during the 14 days in culture (from 166 +/- 25 to 166 +/- 23 mumol (g protein)-1). Surgical preparation of vein rings induced a decrease in the intracellular free amino acid pool (from 166 +/- 25 to 87 +/- 15 mumol (g protein)-1, P < 0.05). This decrease was partially reversed after 14 days in culture (140 +/- 19 mumol (g protein)-1). Although the total amino acid pool in both types of vein rings after 14 days in culture was similar, there were variations in individual amino acid concentrations. Freshly isolated rings showed an increase in glutamine concentration and a decrease in alanine and aspartate concentrations after 14 days in culture. Surgically prepared vein rings showed a decrease in aspartate concentration and an increase in concentrations of glutamine, asparagine, glutamate and glycine. The changes in individual intracellular free amino acid concentrations, which were largely determined by the corresponding concentrations in the medium, indicates that culture media should be supplemented with taurine, aspartate and alanine.

Aged↗
PubMed1995

Direct evidence that the POU family transcription factor Oct-2 represses the cellular tyrosine hydroxylase gene in neuronal cells.

The POU family transcription factor Oct-2 was originally identified in B lymphocytes but has been shown to be expressed in neuronal cells, although it is absent in most other cell types. Cotransfection of Oct-2 expression vectors into nonneuronal cells with a tyrosine hydroxylase promoter/reporter plasmid suggests that Oct-2 can repress this promoter in this artificial situation. Here we report that reduction of endogenous Oct-2 levels in a neuronal cell line by an antisense approach results in an increase in endogenous tyrosine hydroxylase levels. In contrast, the level of the neuronal marker protein PGP9.5 remains unchanged in the antisense lines whereas that of the neuronal nitric oxide synthase decreases. Hence, the tyrosine hydroxylase gene is a natural target for repression by Oct-2 in neuronal cells. The significance of this effect is discussed in terms of the processes that regulate tyrosine hydroxylase gene expression and the role of Oct-2 in neuronal cells.

Animals↗
PubMed1995

U.S. apartheid and the spread of AIDS to the suburbs: a multi-city analysis of the political economy of spatial epidemic threshold.

We compare mechanisms of AIDS diffusion at the county level from five U.S. central city epicenters into their associated metropolitan regions. Four of the five show an expanding 'hollowed out' center of physically and socially devastated, politically and economically abandoned high density minority neighborhoods, surrounded by rings of relatively affluent majority suburban populations. From these centers AIDS diffuses into the suburbs as a single, spatially extended disease ecosystem. The exception, San Francisco, has not yet experienced the 'hollowing out' process and is, we conclude, a major AIDS epicenter markedly less coupled to its suburbs because of that fact. This may constitute one of the few empirical observations of spatial threshold in epidemiology. Our empirical results contradict the conclusions of a recent National Research Council report that AIDS will be largely confined within marginalized urban populations. In reality U.S. urban apartheid, particularly its continuing disruption of minority social structures, has markedly accelerated the diffusion of AIDS into suburban communities. A widespread program of reform, which rebuilds minority physical and social community structures within both city and suburb, is an essential, but largely unrecognized, component to any serious strategy for the control of AIDS in the United States.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Microalbuminuria.

Explore the source record for details and available documents.

Albuminuria↗
PubMed1995

Changes in intracellular concentration of amino acids in human saphenous vein during preparation for coronary artery bypass grafting.

OBJECTIVES: Earlier research on human skeletal and cardiac muscle has shown a fall in the intracellular free amino acid pool, particularly the non-essential amino acids, during surgery. Surgical preparation of the human saphenous vein for coronary artery by pass grafting has been shown to provoke metabolic damage and may therefore induce changes in cellular amino acids which may have long-term implications for the performance of the grafted vein. This work investigates the hypothesis that surgical preparation of saphenous vein induces changes in amino acids. METHODS: Changes in the intracellular free amino acid pool were monitored, using high-performance liquid chromatography (HPLC), in both freshly isolated and surgically prepared human saphenous veins during coronary artery bypass grafting. In order to asses the extent of metabolic damage incurred by surgical preparation, adenosine triphosphate (ATP) levels were also measured. RESULTS: A substantial fall in intracellular free amino acid was associated with surgical preparation of human saphenous vein for coronary artery bypass grafting (190.8 +/- 25 to 106 +/- 18 mumol.g-1 protein, n = 10, P < 0.05). Although the fall was seen in most amino acids detected, it was marked and statistically significant (P < 0.05) for taurine (30.6 +/- 3.1 to 9.0 +/- 2.2 mumol.g-1 protein), glutamate (43.6 +/- 5.6 to 18.2 +/- 4.5 mumol.g-1 protein), glutamine (12.8 +/- 1.6 to 3.3 +/- 1.2 mumol.g-1 protein) and asparagine (9.6 +/- 1.6 to 4.1 +/- 1.0 mumol.g-1 protein). The fall in tissue taurine which would be largely due to transport showed a strong positive correlation with the fall seen in glutamate, glutamine and asparagine. ATP levels significantly decreased as a result of surgical preparation (279 +/- 44 to 96 +/- 21 nmol.g-1 wet weight, P < 0.05). The fall in ATP was accompanied by an increase in alanine/glutamate ratio which may reflect increased glutamate-alanine transaminase activity and therefore metabolic changes. CONCLUSIONS: The metabolic damage associated with surgical preparation of human saphenous vein for coronary artery bypass grafting is accompanied by a fall in the intracellular free amino acid pool which is marked and statistically significant for glutamate, taurine, glutamine and asparagine. The fall is likely to be due to transport metabolism may also contribute. This may have important implications for the functional recovery of the grated vein.

Adenosine Triphosphate↗
PubMed1994

Metabolism of [3H] 17 beta-dihydroequilin and [3H] 17 beta-dihydroequilin sulfate in normal postmenopausal women.

The metabolism of 17 beta-dihydroequilin and 17 beta-dihydroequilin sulfate was investigated after intravenous administration of [3H] 17 beta-dihydroequilin and [3H] 17 beta-dihydroequilin sulfate to postmenopausal women. Urine was collected for 3 days and 46.2 +/- 10.5% and 54.5 +/- 8.7% of the injected dose of [3H] 17 beta-dihydroequilin and [17 beta-3H]dihydroequilin sulfate was excreted in the urine respectively. The estrogens present in urine were extracted and fractionated into unconjugated, sulfate, and glucuronide conjugated forms. With both precursors, the major amount (63-64%) of metabolites were excreted in the urine conjugated with glucuronic acid. From the unconjugated, sulfate, and glucuronide fraction, 17 beta-dihydroequilenin, 17 beta-dihydroequilin, equilenin, and equilin were isolated. The conversions with both precursors were similar and 17 beta-dihydroequilenin was the major metabolite isolated from all three fractions; however, the highest levels of all four metabolites were present in the glucuronide fraction. Along with these identifiable metabolites, a large amount (51-81%) of radioactivity was present in the form of metabolites which are more polar than any of the known ring-B unsaturated estrogens. These appear to be polyhydroxy 17 beta-reduced ring-B unsaturated estrogens which remain to be identified. The in-vivo formation of equilenin and 17 beta-dihydroequilenin indicates the presence of the enzyme 6.8(9) steroid dehydrogenase in humans.

Equilin↗
PubMed1994

Will AIDS be contained within U.S. minority urban populations?

Recent empirical research, and a simple stochastic modeling exercise, suggest that affluent suburban communities are at increased risk for the diffusion of HIV from present inner city epicenters, while the 'core group' construct of sexually transmitted disease theory suggests, somewhat counter-intuitively, that the hypercongregated and strongly self-interacting nature of affluent heterosexual elites in the U.S. places them at significant and increasing risk as well. In turn, a growing body of work strongly associates high HIV prevalence in minority urban populations with the processes of coupled physical and social disintegration which have produced the now-common and politically-generated 'hollowed out' pattern of U.S. cities. We conclude that a return to the principles of the Great Reform Movement, which first brought public health and public order to U.S. urban areas, is a necessary, but at present largely unrecognized, component to any successful national program to control AIDS in the United States, and particularly to stem the diffusion of HIV into heterosexual populations outside present diseases epicenters.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The resurgence of tuberculosis in New York City: a mixed hierarchically and spatially diffused epidemic.

For New York City from 1978 to 1990, plotting the 3-year running averages of citywide new tuberculosis cases against the middle year yielded an S-shaped curve, with the inflection point at 1983 between early slow and late rapid rise. The inflection in the S curve appears to be associated with hierarchical establishment of secondary epicenters, and the phase of rapid rise in new cases seems to be associated with spatial diffusion from both the primary and secondary epicenters.

Humans↗