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Biomedical subjects

R Wallace

Publications and source records attributed to R Wallace.

At least 73 records · Page 4Linked to original sources
PubMed1996

The late-stage diagnosis of colorectal cancer: demographic and socioeconomic factors.

OBJECTIVES: This study described factors related to colorectal cancer stage at diagnosis. METHODS: Logistic regression analyses were used on data from the New York State Tumor Registry and US Census area-level social class indicators. RESULTS: After the effects of other predictors were controlled for, the odds of late-stage cancer increased as age decreased; women and African Americans were significantly more likely to have late stage than men and Whites; and individuals living in areas of low socioeconomic status (SES) were significantly more likely to be diagnosed at late stage than those living in higher SES areas. Stratified analyses showed that living in a low SES area was the most important determinant of stage for all age, race, gender and source-of-care groups. CONCLUSIONS: While all populations would benefit from the systematic use of screening socioeconomically disadvantaged groups may also benefit from targeted screening.

Adult↗
PubMed1996

Engelmann's disease: a 45-year follow-up.

We report a 45-year follow-up of a patient with Engelmann's disease previously described in 1950, showing progression of the disease with unique involvement of the femoral capital epiphyses. The case is compared with others to add some information about the later stages of a disease which is not fully understood.

Aged↗
PubMed1996

Biometrological assessment of the preventive effect of a miconazole spray powder on athlete's foot.

Prevention of athlete's foot is a difficult problem. Using non-invasive biometrological methods, we evaluated the changes induced in the stratum corneum by a 3-week treatment with miconazole spray powder. A total of 16 athletes apparently at risk of developing tinea pedis, but without any evidence for the disease at the time of inclusion, participated in the study. They applied the medicated powder to one foot daily, while the other foot remained untreated to serve as a control. No adverse events occurred. In comparison with the control site, the capacitance of the toeweb skin was significantly reduced by the treatment. The ex vivo bioassay of dermatophyte culture on stratum corneum demonstrated a significant inhibition of growth of Trichophyton mentagrophytes var. interdigital at the treated site. The results of this study provide indirect evidence that the regular use of miconazole spray powder decreases the risk of developing athlete's foot.

Adult↗
PubMed1995

Fixing human factor IX (fIX): correction of a cryptic RNA splice enables the production of biologically active fIX in the mammary gland of transgenic mice.

Transgenic mice and sheep secrete only low levels of human factor IX in their milk because of an aberrant splicing of the transgene RNA in the mammary gland. Removal of the cryptic 3' splice site prevents this splicing and leads to the production of relatively high levels of factor IX. The purified protein is fully active showing that the mammary gland is capable of the efficient post-translational modification of this protein and that transgenic animals are a suitable means of its production.

Animals↗
PubMed1995

Microscopic computation in human brain evolution.

When human psychological performance is viewed in terms of cognitive modules, our species displays remarkable differences in computational power. Algorithmically simple computations are generally difficult to perform, whereas optimal routing or "Traveling Salesman" Problems (TSP) of far greater complexity are solved on an everyday basis. It is argued that even "simple" instances of TSP are not purely Euclidian problems in human computations, but involve emotional, autonomic, and cognitive constraints. They therefore require a level of parallel processing not possible in a macroscopic system to complete the algorithm within a brief period of time. A microscopic neurobiological model emphasizing the computational power of excited atoms within the neuronal membrane is presented as an alternative to classical connectionist approaches. The evolution of the system is viewed in terms of specific natural selection pressures driving satisfying computations toward global optimization. The relationship of microscopic computation to the nature of consciousness is examined, and possible mathematical models as a basis for simulation studies are briefly discussed.

Algorithms↗
PubMed1995

Epithelial proliferation and differentiation in the mammary gland do not correlate with cFABP gene expression during early pregnancy.

Cardiac fatty acid binding protein (cFABP) is abundantly expressed in the nondividing, functionally differentiated mammary epithelium. It is very closely related, if not identical to, a previously described protein termed mammary derived growth inhibitor (MDGI). In vitro studies suggest that low concentrations of diffusible cFABP/MDGI may play a hormone-like role in limiting proliferative activity and promoting functional differentiation of this tissue, but no in vivo data to support this idea have been published. To test this hypothesis, we compared the levels of cFABP mRNA with both the epithelial DNA labelling index and levels of beta-casein mRNA in wild-type mice. We also investigated the effect of a precocious experimental increase of cFABP levels in the mammary gland of transgenic mice on the labelling index and beta-casein mRNA levels. This was accomplished by expressing a bovine cFABP cDNA under the control of the ovine beta-lactoglobulin (BLG) gene promoter. We found that although both the DNA labelling index, beta-casein mRNA levels, and cFABP mRNA levels in wild-type mice are developmentally regulated, they do not correlate with each other during early pregnancy in individual mice. Moreover, a three- to fourfold increase of total cFABP mRNA in two transgenic lines did not affect the DNA labelling index or the levels of beta-casein mRNA, an established marker of differentiation of the mammary epithelium, at this developmental stage. These data suggest that epithelial DNA synthesis, beta-casein gene expression, and expression of the cFABP gene are regulated independently in the proliferatively active mammary gland and that the rapidly dividing mammary epithelial cells are not susceptible to the action of cFABP during early pregnancy.

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

Description of two new species of Halomonas: Halomonas israelensis sp.nov. and Halomonas canadensis sp.nov.

Six well-known strains of halotolerant bacteria, including two strains previously identified only as NRCC 41227 and Ba1, have been compared using 125 phenotypic characters and DNA-DNA hybridization. Although these strains represent some of the most heavily studied salt-tolerant bacteria, they have never been taxonomically compared. The data presented show that these bacteria form a relatively homogeneous group related at the genus level. The taxonomic comparison showed that these six organisms represented four distinct species all related above the 65% Jaccard coefficient level. In addition to two previously identified bacterial species, Halomonas elongata (ATCC 33173T) and Halomonas halodurans (ATCC 29686T), the strains included in this study represent two previously unnamed Halomonas species. These two new taxa have been assigned the names Halomonas israelensis (ATCC 43985T) and Halomonas canadensis (NRCC 41227T = ATCC 43984). DNA-DNA hybridization show that these two species are related to the type species H. elongata at 54.9 and 48.9%, respectively.

Culture Media↗
PubMed1995

Impact of access and social context on breast cancer stage at diagnosis.

This study examined the impact of individual demographic characteristics (age, race/ethnicity, and type of reporting hospital), together with measures of social context, including area of residence socioeconomic status (SES), change in SES, and access to screening (area mammography capacity), on breast cancer stage at diagnosis among New York City residents diagnosed between 1980 and 1985. Three logistic regression models evaluated the impact of individual variables, social context variables, and both classes of variables combined on the outcome of having late-stage (regional or distant) compared to early-stage (local) cancer. The logistic regression models indicated that women aged 50 to 64 years were independently more likely to have late-stage cancer than those younger or older. Controlling for individual and social context variables, African American women were 25 percent more likely than White women to have late-stage breast cancer (p < 0.0001); higher odds seen in the individual model for Hispanic women disappeared after controlling for area SES. In the combined model, women diagnosed from public hospitals were 44 percent more likely to have late-stage disease than those diagnosed in nonpublic settings (p < 0.0001). In both the social context and combined models, area mammography capacity was a significant independent predictor of stage (p = 0.016); area-level SES, but not change in SES, was independently related to late-stage disease (p = 0.002). These data suggest that breast cancer control activities should more actively ensure adequate access to screening, particularly for minorities, populations living in socioeconomically disadvantaged areas, and those cared for in the public sector.

Adult↗
PubMed1995

Expression of the v-Mos oncogene in male meiotic germ cells of transgenic mice results in metaphase arrest.

To explore the role of pp39mos in male germ cell meiosis, we have constructed transgenic mice carrying either the c-Mos or v-Mos genes linked to the human male germ cell-specific phosphoglycerate kinase-2 promoter. All male transgenic mice bearing the v-Mos but not the c-Mos construct were sterile due to arrest of germ cells at metaphase I. Immunocytochemistry performed on sections from control and c-Mos transgenic testes with eight different monoclonal and polyclonal antisera against either alpha-, beta- or gamma-tubulins demonstrated that all could recognize MI spermatocyte spindles from control and c-Mos transgenics, but only one monoclonal anti-microtubule sera decorated the spindles of v-Mos-arrested meiotic figures. Western blot analyses with this one serum revealed a change in proteins in the v-Mos samples. Immunocytochemistry with the MPM-2 monoclonal antibody, which is specific for epitopes phosphorylated during mitosis, demonstrated an increase in cytoplasmic and spindle-associated phosphoproteins in arrested v-Mos spermatocytes. Western analysis with MPM-2 showed an increase in a M(r) 50,000-55,000 and a M(r) 25,000-29,000 protein in Mos transgenic testes when compared to controls. An anti-MAP kinase antibody demonstrated an increase in all four MAP kinases in testes of transgenic mice. Thus, overexpression of pp39v-mos during male germ cell meiosis resulted in an alteration of various cell cycle related kinases and cytostatic factor-like arrest at MI.

Animals↗
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

Association of education with incidence of cognitive impairment in three established populations for epidemiologic studies of the elderly.

We analyzed the association of education, occupation, and sex with incidence of cognitive impairment using data from three communities in the Established Populations for Epidemiologic Studies of the Elderly (EPESE) projects (New Haven, East Boston, and Iowa). Participants were initially interviewed in 1981-1983, with follow-up 3 and 6 years later. Incident cognitive impairment was defined on the basis of either: (1) increase in the number of errors in Short Portable Mental Status Questionnaire (SPMSQ) (i.e. from a baseline level below the cutoff value to a score above the cutoff), or (2) inability to respond to interview questions at a follow-up contact (requiring a proxy informant), or (3) death with a recorded diagnosis of a dementing illness. In multiple logistic regression models, the major factors predicting the development of cognitive impairment were advanced age, any errors on baseline SPMSQ, 8 or fewer years of education, and occupation. Education and occupation remained significant predictors after controlling for age, site, sex, stroke, and baseline SPMSQ score.

Aged↗
PubMed1994

A fractal model of HIV transmission on complex socio-geographic networks. Part 2: spread from a ghettoized 'core group' into a 'general population'.

"Study of the initial stages of HIV transmission along a 'sociogeographic network'--a large, complex, spatially focused social network with possibly fractal geometry--is extended to include interaction between a low-dimensional ghettoized 'core group' within which the disease spreads very rapidly and a higher dimensional, more loosely structured 'general population' in which spread is relatively slow. A mathematical modeling exercise suggests that contextually modulated interaction between them can be highly nonlinear and may greatly increase the initial rate of disease transmission within the general population. This work contributes to a growing body of literature which suggests that programs to control HIV infection within the majority heterosexual population of the United States will fail spectacularly without particular focus on the coupled physical and social stabilization and rehabilitation of the urban ghettoes of marginalized populations which are the present, and rapidly expanding, disease epicenters. Evidence suggests their continued disintegration can both increase disease rates within the epicenters and increase the coupling between core groups and general populations by creating large numbers of spatially or economically displaced refugees."

Americas↗
PubMed1994

Chromosomal position effects and the modulation of transgene expression.

Chromosomal position effects can influence strongly the transcription of foreign genes in transgenic animals. This results in low frequencies and levels of gene expression and, in some cases, in aberrant patterns of expression. Strategies for overcoming these effects are described with particular reference to their application in embryonic stem cells.

Animals↗