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Biomedical subjects

R Wallace

Publications and source records attributed to R Wallace.

At least 109 records · Page 6Linked to original sources
PubMed1991

AIDS deaths in the Bronx 1983-1988: spatiotemporal analysis from a sociogeographic perspective.

"Patterns of AIDS deaths, in space and time, are examined for the populous Bronx section of New York City in view of the continuing massive destruction of housing and disruption of community which has affected the South Bronx since the early 1970s. Annual Bronx AIDS deaths are studied simultaneously in geographic space and in a dual 'social variate' space, and it is found that study of linked changes in each deeply illuminates patterns in both. This analysis reinforces a rapidly growing body of work which suggests control of AIDS in the United States, particularly prevention of a widespread and relentlessly rising heterosexual phase of the epidemic, may well prove impossible without a timely, general, and considerable program of reform and renewal for its disintegrating inner cities."

Acquired Immunodeficiency Syndrome↗
PubMed1990

Urban desertification, public health and public order: 'planned shrinkage', violent death, substance abuse and AIDS in the Bronx.

Techniques and approaches from population and community ecology, along with theoretical viewpoints from criminology and the 'social support hypothesis' of health maintenance, are used to examine recent patterns of rising homicide and suicide, intensified substance abuse, low birth weight and AIDS deaths in the Bronx section of New York City. Empirical and theoretical analyses strongly imply present sharply rising levels of violent death, intensification of deviant behaviors implicated in the spread of AIDS, and the pattern of the AIDS outbreak itself, have been gravely affected, and even strongly determined, by the outcomes of a program of 'planned shrinkage' directed against African-American and Hispanic communities, and implemented through systematic and continuing denial of municipal services--particularly fire extinguishment resources--essential for maintaining urban levels of population density and ensuring community stability. This work complements a recent study by McCord and Freeman [1. New Engl. J. Med. 332, 173, 1990] on Harlem, and suggests the present overburdening of New York's criminal justice system arises from almost exactly the same causes as its accelerating inability to meet demands for acute medical service, so-called 'medical gridlock', in that both are expressions of the increasing social disorganization of poor communities initiated and continued in considerable part by government policy. The critical role played by improper policy in triggering the syndrome suggests ecologically informed interventions, particularly essential service restoration, may hold the potential for great positive impact.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Relationship between diabetes mellitus mortality rates and drinking water magnesium levels in Iowa.

A recent ecologic study has suggested a relationship between mortality from diabetes mellitus and levels of magnesium in drinking water. However, diabetes mortality rates were from aggregate data for the entire geographic area under study. The state of Iowa has data resources available to determine diabetes mortality rates for individuals on known water supplies in Iowa and magnesium levels for raw drinking water supplies. To determine the presence of this relationship in the state of Iowa, mortality rates from 1976 through 1985 for diabetes as an underlying cause of death and for major cardiovascular disease with diabetes as an ancillary cause of death were compared for individuals from towns in Iowa with populations of 1,000 to 10,000. At the stratification levels of magnesium in municipal drinking water used in this study, no significant differences were found in diabetes mortality rates.

Cardiovascular Diseases↗
PubMed1989

Hyperammonemia decreases body fat content in rat.

We have developed an animal model of hyperammonemia consisting of feeding rats a diet containing 20% (w/w) ammonium acetate. Ingestion of this diet markedly affects carcass composition, with a 46% reduction in lipid content. The ammonium diet alters levels of several key compounds involved in lipid metabolism. Long-chain acylcarnitine is increased in liver by approx. 60% while free carnitine and acetylcarnitine are unaffected. The hepatic content of acetyl-CoA increases by approx. 50%. The level of ketone bodies in blood increases by 32% but remains unchanged in liver. Our data indicate that hyperammonemia alters lipid metabolism and results in a significant decrease in body lipid content.

Acetates↗
PubMed1989

Perinatal lethality (ple): a mutation caused by integration of a transgene into distal mouse chromosome 15.

We have used cytogenetic and recombinational analysis to determine the position of a transgene integrated into the mouse genome. The transgene maps to band F on the physical map of mouse chromosome 15 by in situ analysis and is tightly linked genetically to a cluster of loci that include the mutations caracul (Ca) and microcytic anemia (mk). Genetic analysis of the offspring of noninbred animals carrying the transgene and marker loci demonstrates a significant deficiency of homozygous progeny at weaning. When inbred mice heterozygous for the transgene are mated, about one-quarter of their offspring are homozygous; none of these animals survives more than 1 day after birth. It appears likely that a recessive insertional mutation has occurred as a result of transgene integration into a locus required for postnatal viability. We call this mutation transgenic perinatal lethality (Tg.ple).

Animals↗
PubMed1988

Long-term ingestion of ammonium inhibits lysosomal proteolysis in rat liver.

A standard diet was supplemented with ammonium acetate (20%, w/w). The effect on liver protein degradation of oral administration of the ammonium diet to rats for 6 weeks has been studied. It is shown that lysosomal proteolysis is markedly decreased (by 62%) while non-lysosomal proteolysis is inhibited by 11%. This is the first report showing that ammonium ingestion inhibits liver proteolysis.

Acetates↗
PubMed1988

Single-step induction of mammary adenocarcinoma in transgenic mice bearing the activated c-neu oncogene.

We have used transgenic mice that carry an activated c-neu oncogene driven by a mouse mammary tumor virus (MMTV) promoter to assess the stepwise progression of carcinogenesis in mammary epithelium. Unlike the stochastic occurrence of solitary mammary tumors in transgenic mice bearing the MMTV/c-myc or the MMTV/v-Ha-ras oncogenes, transgenic mice uniformly expressing the MMTV/c-neu gene develop mammary adenocarcinomas that involve the entire epithelium in each gland. Because these tumors arise synchronously and are polyclonal in origin, expression of the activated c-neu oncogene appears to be sufficient to induce malignant transformation in this tissue in a single step. In contrast, expression of the c-neu transgene in the parotid gland or epididymis leads to benign, bilateral epithelial hypertrophy and hyperplasia which does not progress to full malignant transformation during the observation period. These results indicate that the combination of activated oncogene and tissue context are major determinants of malignant progression and that expression of the activated form of c-neu in the mammary epithelium has particularly deleterious consequences.

Adenocarcinoma↗
PubMed1988

A synergism of plagues: "planned shrinkage," contagious housing destruction, and AIDS in the Bronx.

Techniques adapted from population and community ecology, quantitative geography, and epidemiology are applied to ecosystem and environmental index data on the Bronx in an attempt to understand the origins and potential impacts of rampant spread of human immunodeficiency virus (HIV) and its sequelae of acquired immunodeficiency syndrome (AIDS) in that borough: Recent work by Drucker and Vermund (1987), ("Estimating Prevalence of Human Immunodeficiency Virus Infection in Urban Areas with High Rates of Intravenous Drug Abuse: A Model of the Bronx in 1987," Poster presented at the Third International Conference on AIDS, June 2, 1987) estimates HIV seroprevalence levels of from 8 to 21% among men of age 25-44 in the south Bronx, at this writing, comparable to the cities of Central Africa. It is found that the "South Bronx" process of fulminating, contagious urban decay which devastated the region in the 1970s, and its associated forced population migrations, spread intravenous drug abuse, the principal HIV vector in the Bronx, from a geographically contained center in the South-Central Bronx to a virtually borough-wide phenomenon. This has significantly complicated attempts to contain HIV infection, both by shredding the social networks which are the natural vehicles for education, and by vastly enlarging the area requiring intensive targeting. Since the "planned shrinkage" municipal service cuts which triggered the "South Bronx" burnout persist, and since levels of housing overcrowding now approach those of the early 1970s in the Bronx, it is expected that a new outbreak of contagious urban decay will occur, likely again dispersing population and seriously compromising any in-place HIV control strategies. If overt AIDS itself becomes a contributor to urban deterioration in overcrowded neighborhoods susceptible to "South Bronx" process, we could then see a nonlinear ecosystem coupling between AIDS, contagious urban decay, and population shift. Elementary mathematical models are provided. Thus, in striking contrast to the middle-class male homosexual community, successful control of HIV infection in the Bronx, and by inference in other devastated ghetto communities, seems predicated on quick reestablishment of demographic stability: The tools to make the tools for control must first be reconstructed. Necessary elements of any program toward this end are briefly outlined. AIDS in the Bronx and similar areas, like tuberculosis, seems increasingly a marker disease of extreme poverty, and again like tuberculosis, seems increasingly a marker disease of extreme poverty, and again like tuberculosis, may well form an important reservoir for further spread or resurg

Acquired Immunodeficiency Syndrome↗
PubMed1988

High ammonia levels in brain induce tubulin in cerebrum but not in cerebellum.

Ingestion of large amounts of ammonium increases markedly the content of tubulin in brain. The effect on tubulin induction of ammonium ingestion for up to 100 days was investigated. Brain tubulin content showed a rapid initial increase (28%) at 2 days and reached 50% after 100 days on the diet. To discern if ammonia, the increase in urea synthesis, or both was responsible for tubulin induction, rats were maintained at several levels of uremia (by administering diets containing 0 to 80% protein) or in hyperammonemia (by urease treatment). Only ammonium administration in the diet and urease injection induced tubulin in brain. Tubulin was quantified in three different brain regions. There was a regional selectivity of tubulin induction by ammonia in rat brain. Whereas the cerebellum remained unaltered, the paleencephalon showed the highest increase, and the cerebral cortex exhibited only a modest increase.

Ammonia↗
PubMed1988

Lysis of halobacteria in bacto-peptone by bile acids.

All tested strains of halophilic archaebacteria of the genera Halobacterium, Haloarcula, Haloferax, and Natronobacterium lysed in 1% Bacto-Peptone (Difco) containing 25% NaCl, whereas no lysis was observed with other strains belonging to archaebacteria of the genera Halococcus, Natronococcus, and Sulfolobus, methanogenic bacteria, and moderately halophilic eubacteria. Substances in Bacto-Peptone which caused lysis of halobacteria were purified and identified as taurocholic acid and glycocholic acid. High-performance liquid chromatography analyses of peptones revealed that Bacto-Peptone contained nine different bile acids, with a total content of 9.53 mg/g, whereas much lower amounts were found in Peptone Bacteriological Technical (Difco) and Oxoid Peptone. Different kinds of peptones can be used to distinguish halophilic eubacteria and archaebacteria in mixed cultures from hypersaline environments.

Journal Article↗
PubMed1988

Incidental adnexal neoplasms at cesarean section.

A 10-year retrospective review was conducted of incidental adnexal neoplasms found at the time of cesarean section. During the 10-year period between July 1, 1976 and June 30, 1986, 17,902 cesarean sections were performed at Women's Hospital of the Los Angeles County/University of Southern California Medical Center. Adnexal neoplasms were identified with an incidence of one neoplasm per 197 cesarean sections. When a neoplasm is discovered during surgery, conservative surgery is recommended.

Adnexal Diseases↗
PubMed1987

Coexpression of MMTV/v-Ha-ras and MMTV/c-myc genes in transgenic mice: synergistic action of oncogenes in vivo.

We have derived and mated separate strains of transgenic mice that carry either the v-Ha-ras or the c-myc gene driven by the mouse mammary tumor virus (MMTV) promoter/enhancer. Mice carrying the MMTV/v-Ha-ras transgene manifest two distinct disturbances of cell growth. The first, a benign hyperplasia of the Harderian lacrimal gland, is diffuse, involves the entire gland, and likely requires only the abnormal action of the v-Ha-ras gene. The second involves the focal development of malignancies of mammary, salivary, and lymphoid tissue and likely requires additional somatic events. When the MMTV/v-Ha-ras and MMTV/c-myc strains are crossed to yield hybrid mice, their joint action results in a dramatic and synergistic acceleration of tumor formation. Since these tumors arise stochastically and are apparently monoclonal in origin, additional somatic events appear necessary for their full malignant progression, even in the presence of activated v-Ha-ras and c-myc transgenes.

Adenocarcinoma↗
PubMed1987

Changing patterns of hypertension, diabetes, obesity and diet among Melanesians and Micronesians in the Solomon Islands.

A cross-sectional survey of diabetes, hypertension, obesity and dietary patterns has been conducted in the Western Province of the Solomon Islands. Three groups--traditional and more urbanized Melanesians and semitraditional Micronesians--were compared. Abnormal glucose tolerance was rare (less than 1% over all) in Melanesians regardless of acculturation, but was present in 9.7% of adult Micronesians in whom it was associated with age; obesity; female sex; and a diet that was high in energy and refined carbohydrates. Hypertension, which was associated with advancing age and obesity, was recorded in 6.0% and 8.3% of traditional and partly urbanized Melanesians, respectively, and in 4.8% of Micronesians. Systolic and diastolic blood pressures correlated significantly with age for all except traditional Melanesian women among whom the association was limited to the systolic blood pressure only. Significant correlation coefficients were recorded between diastolic blood pressure and body mass index for both sexes and all groups, and between systolic blood pressure and body mass index for all women but only for Micronesian men. Dramatic differences in life-style and dietary patterns are described for rural and more urbanized Melanesians among whom the mean daily urinary sodium outputs were 67 and 119 mmol/L, respectively.

Acculturation↗