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Biomedical subjects

T L Anderson

Publications and source records attributed to T L Anderson.

At least 19 recordsLinked to original sources
PubMed1999

Characteristics of inconsistent respondents who have "ever used" drugs in a school-based sample.

This study examines the predictors of inconsistent responses from adolescents to questions about whether they ever used alcohol, cigarettes, and marijuana. Male adolescents had significantly higher rates of inconsistent responses than female adolescents. Black and Hispanic adolescents had significantly higher rates of inconsistent responses regarding ever using alcohol and cigarettes (only for Black) than White adolescents. The subjects' living status and academic achievements were significant predictors of inconsistent responses regarding ever using marijuana. Thus, these results are consistent with the notion that inconsistent responses may bias the estimation of the prevalence of ever using drugs in multivariate analyses.

Adolescent↗
PubMed1998

Placental pathophysiology of the twin oligohydramnios-polyhydramnios sequence and the twin-twin transfusion syndrome.

Currently accepted sonographic criteria for antenatal diagnosis of twin-twin transfusion (TTT) syndrome include a monochorionic placenta with same-sex twins, marked growth discordance, and oligohydramnios of the growth-retarded twin with coexistent polyhydramnios of the larger twin. Our previous report of nine women fulfilling these criteria, examined using sequential funipuncture of both fetuses, demonstrated inter-twin blood transfusion in only four cases (44 per cent). It was proposed that traditional sonographic criteria actually describe a heterogeneous group of disorders more appropriately described as the twin oligohydramnios-polydramnios sequence (TOPS). True TTT is a subset of this population, the antenatal diagnosis of which requires specific demonstration of transfusion from one fetus (donor) to the other (recipient). In this report, antenatal placental evaluation has been correlated using duplex pulsed-wave Doppler analysis of arterial blood flow velocity with postpartum gross and histopathologic evaluation of the placenta, with special attention to microvasculature. There was a higher incidence of resistance to blood flow, abnormal umbilical cord insertion, and diminished placental microvasculature associated with oligohydramnic growth-retarded (donor) twins when compared with polyhydramnic (recipient) twins. Based on these observations, it is proposed that TTT and TOPS represent asymmetric placental insufficiency resulting from aberrant placentation.

Blood Flow Velocity↗
PubMed1998

Drug identity change processes, race, and gender. I. Explanations of drug misuse and a new identity-based model.

The present paper explores race and gender differences in a recent theoretical model (Anderson, 1994), consisting of several micro- and macrofactors, that helps explain the identity-related processes of drug misuse. The approach is qualitative, featuring in-depth interviewing with 45 self-identified drug addicts. The study uncovered support for the general concepts of the identity-based model across four subgroups: Black females, White females, Black males, and White males. However, important race and gender differences emerged. Gender and race-related socialization and stratification explain most of the differences and suggest reconceptualization of the model. The investigation further demonstrates the promise of identity-based approaches in extending our knowledge of the etiology of drug misuse and related intervention policies.

Adult↗
PubMed1998

Drug identity change processes, race, and gender. II. Microlevel motivational concepts.

Events and experiences that are damaging and which sever young people from normative ideals and positively sanctioned statuses (marginalization) create feelings of alienation or social isolation within them and earn them undesired statuses and treatment from important others. An underlying premise of the drug-use identity change model is that individuals are motivated toward drug-related identity change because of such socially defined problems with existing ego identities (ego identity discomfort and lost control in defining an identity) in childhood and early adolescence and that certain macrolevel phenomena (e.g., social appraisal sources and social climate conducive to drug use) provide an opportunity structure for that change. Part 2 of this paper describes each of the three motivational concepts and how they vary by race and gender in the process of becoming a drug misuser. Part 3 discusses the two macrolevel opportunity concepts and how they vary by race and gender.

Adolescent↗
PubMed1998

Drug identity change processes, race, and gender. III. Macrolevel opportunity concepts.

Throughout the 20th century, scholars studying drug misuse have pinpointed various macrolevel (broad cultural and social structural) influences on the problem. The drug identity change model includes two such macrolevel factors. It maintains that social climates conducive to drug use (availability and popularity of drugs over the years) and social appraisal sources provide important opportunities for drug-related identity change. Social climates conducive to drug use help foster the formation of small groups centered on drug-related activity and meaning systems, i.e., social appraisal sources. Identification with these groups helps reduce one's ego identity discomfort or temporarily solve one's identity problems. It is through this process, the model contends, that young people change from nondrug users to drug misusers. Part 3 discusses these two concepts and how they work in the lives of the four race and gender groups studied here.

Adolescent↗
PubMed1996

Inclusion body myositis in HIV-1 and HTLV-1 infected patients.

Sporadic inclusion body myositis (IBM) is the most common inflammatory myopathy affecting patients over the age of 50 years. Dysimmune and degenerative aetiologies have been postulated, but viral infections have not been associated with the disease. Two HIV-I (human immunodeficiency virus type 1) infected men and one woman infected with HTLV-1 (human T cell leukaemia virus type 1) developed progressive proximal muscle weakness unrelated to antiretroviral therapy. Their muscle biopsies were studied by light and electron microscopy, by immunocytochemistry to determine the expression of major histocompatibility complex (MHC) molecules and identify the type of infiltrating cells and T cell receptor (TCR) subunits, and by reverse transcription-polymerase chain reaction (RT-PCR) and single or double immunocytochemistry to search for retrovirally infected endomysial cells. The clinical features were consistent with sporadic IBM. The muscle biopsies showed primary endomysial inflammation, red-rimmed vacuoles, amyloid deposits, eosinophilic inclusions, and small round fibres in groups, all diagnostic of IBM. The muscle fibres expressed MHC class-1 antigens and were invaded primarily by CD8+ T-lymphocytes preferentially bearing TCR V beta 5.1 and V beta 13 chains. The HIV-1 or HTLV-1 antigens were detected only on endomysial macrophages on or around muscle fibres, but not within the muscle fibres. We conclude that IBM occurs in HIV-1 and HTLV-1 infected individuals and has a clinical, histological and immunological pattern identical to sporadic IBM in the non-retrovirally infected patients. Retroviruses do not directly infect the muscle, but persistent retroviral infections may provide superantigenic stimulation and trigger an endomysial inflammatory response identical to that occurring in sporadic IBM.

Adult↗
PubMed1996

Placenta previa increta diagnosed at 18 weeks' gestation. Report of a case with sonographic and pathologic correlation.

BACKGROUND: Placenta previa incerta, although uncommon, assumes considerable clinical significance because of the morbidity associated with severe hemorrhage, uterine perforation and infection. The majority of cases are unanticipated and initially identified intraoperatively. CASE: Placenta accreta was diagnosed sonographically at 18 weeks' gestation in a multipara who had previously undergone cesarean delivery. Additionally, the gestation was complicated by chronic renal failure secondary to systemic lupus erythematosus. After appropriate counseling, total abdominal hysterectomy was performed prior to fetal viability. CONCLUSION: Early sonographic evaluation of the placenta is recommended for those at significant risk of invasive placentation. Timely detection facilitates proper preparation and should reduce maternal morbidity.

Adult↗
PubMed1995

Malignant external otitis due to Aspergillus flavus with fulminant dissemination to the lungs.

Malignant external otitis secondary to aspergillus infection is rare, and only 10 cases have been reported in the literature. Nine of 10 patients responded to therapy and survived their infection. There have been no previous reports of dissemination of Aspergillus species from the ear to other organs. We describe a case of malignant external otitis due to Aspergillus flavus that disseminated hematogenously to the lungs. The result was an overwhelming, miliary pulmonary infection, which progressed very rapidly to respiratory failure and death. Pathological examination of lung tissue revealed multiple microabscesses and hyphal elements that had invaded the lung parenchyma from small pulmonary arteries.

Adult↗
PubMed1995

Congenital hemangiopericytoma of the clitoris.

Hemangiopericytoma is a rare vascular tumor that is believed to arise from the pericyte of Zimmermann. Approximately 10% of cases occur in children and a third are congenital. To our knowledge we report the first case of a congenital hemangiopericytoma arising from the clitoris, describe its management and review the literature.

Clitoris↗
PubMed1994

Evaluation of the hepatobiliary excretion of technetium-99m-MAG3 and reconstitution factors affecting radiochemical purity.

UNLABELLED: Technetium-99-MAG3 is a renal tubular function agent. However, sporadic liver and gallbladder visualization have raised questions about kit stability, impurities and nonrenal routes of excretion. To address these issues, studies were conducted to optimize the labeling efficiency of the TechneScan MAG3 kit and to evaluate the hepatobiliary excretion of the MAG3 complex. METHODS: Thirty-six vials of the commercial formulation of 99mTc-MAG3 were prepared according to manufacturer's instructions and evaluated for radiochemical purity using two methods: a combination of high-performance liquid chromatography and paper chromatography (HPLC/PC); and the manufacturer's miniature chromatography system (Sep-Pak procedure). RESULTS: The labeling efficiency was significantly higher when the kit was reconstituted with 10 ml (96.6%) of saline versus 5 ml (91.4%) (p < 0.01). The radiochemical purity of the kits remained stable for up to 6 hr, but the purity determined by Sep-Pak averaged 2.5% higher than that determined by HPLC procedures (p < 0.01). Rat studies to evaluate renal and hepatobiliary elimination of MAG3 showed no difference in the %ID excreted into the urine by 60 min in all groups of animals studied. However, the %ID excreted into the bile was significantly higher for the kit formulation than the HPLC-purified MAG3, 9.9% versus 6.6% (p = 0.0475). CONCLUSION: The radiochemical purity of the TechneScan MAG3 kit can be improved by reconstituting with larger volumes. In addition, the studies in rats suggest that fasting or kit impurities may be a contributing factor to increased hepatobiliary visualization in patient studies.

Animals↗
PubMed1992

Distribution of tumor-associated glycoprotein-72 (TAG-72) expression throughout the normal female reproductive tract.

Compared with the degree of investigation of stage-specific expression of tumor-associated glycoprotein-72 (TAG-72) in fundal endometrium, other regions of the female reproductive tract have not received comparable attention. Regional, cell-type-specific, and temporal differences in estrogen receptor and progesterone receptor distribution and concentration among these tissues should make such examination beneficial to our understanding of hormonal regulation of TAG-72 expression. The pattern of monoclonal antibody (MAb) B72.3 recognition in the cervix, uterus, oviduct, and ovary was examined by immunohistochemistry during both the proliferative and secretory intervals of the normal menstrual cycle. Intense immunoreactivity in fundal endometrium was limited to the secretory menstrual interval. Conversely, TAG-72 expression was generally weaker, sporadically distributed, and not stage specific in the lower uterine segment, endocervix, and cervix; no expression was detected in the oviduct or ovary. The disparity in both temporal and spatial distribution of TAG-72 expression throughout the female reproductive tract does not appear to be directly associated with the well-described changes in circulating estradiol or progesterone or the receptors for these steroids. Results suggest that regulation of TAG-72 expression may involve local paracrine/autocrine mechanisms, which in turn may be subject to hormonal influence.

Adult↗
PubMed1992

Response of young asthmatic patients to inhaled sulfuric acid.

The intent of this study was to explore the effects of inhalation of [H+] defined here as acid airborne particles at near ambient concentrations on the pulmonary function of adolescent asthmatic subjects. During rest and exercise, 22 adolescent asthmatic subjects inhaled atmospheres containing either clean air or sulfuric acid particles (H2SO4) through a mouthpiece. The concentration of hydrogen ion at the mouthpiece ([H+]) ranged from 1.18 to 3.59 mumol/m3 (51 to 176 micrograms/m3 of H2SO4). The lower range of [H+] is near the peak values measured during the summer months in the eastern United States and Canada. Pulmonary function and oral ammonia levels were measured before and after exposure in all subjects. Significant group responses to [H+] were seen in FEV1 (p = 0.016) and FVC (p = 0.039) measured 2 to 3 min post-exposure. Also, the slopes of the change in pulmonary function versus [H+] were computed for each subject. The slopes of changes in FEV1 and Vmax50 and Vmax75 versus [H+] were related to the subject's response to a standard exercise treadmill test, specifically to the subject's percentage decrease in FEV1 after exercise challenge. Pulmonary function changes 20 min postexposure did not show a significant group response to [H+] exposure; however, the relationship between percentage FEV1 decrease after exercise and the individual slopes of Vmax50 and Vmax75 persisted for at least 20 min after exposure.

Adolescent↗
PubMed1991

Immunohistochemical localization of gonadotropin-releasing hormone during implantation in the New Zealand white rabbit.

Gonadotropin-releasing hormone was localized immunohistochemically during implantation (gestational days 6 to 14) in the New Zealand White rabbit. During early implantation (days 7 to 9), intense gonadotropin-releasing hormone immunostaining was localized predominantly to the cytoplasm of the nonknob cytotrophoblast with light to moderate staining in the cytoplasm of the syncytiotrophoblast (knob). In later gestation, light to moderate staining of the cytoplasm of the trophoblast at the true placental site was detected. No appreciable change in staining was noted after day 10. Fetal membranes, identified after day 10, showed intense and unchanging immunostaining for gonadotropin-releasing hormone. Obplacental giant cells showed light to moderate nuclear and cytoplasmic gonadotropin-releasing hormone immunostaining. Light to moderate gonadotropin-releasing hormone immunostaining was also noted in the cytoplasm of uterine epithelium and glands. We conclude that immunoreactive gonadotropin-releasing hormone is present in the cytotrophoblast at the time of the earliest embryo-uterine interactions and may play a significant role in implantation and embryo survival.

Animals↗
PubMed1991

Effect of estrogen on human endometrial epithelial cell growth and differentiation in vitro.

Although physiologic parameters regulating endometrial proliferation and secretory maturation during the normal menstrual cycle are well characterized, cellular and molecular interactions directing these events under the influence of a changing hormonal milieu remain unclear. In the present study, the effect of estradiol on the growth and acquisition of differentiated function of purified endometrial epithelium was examined in an established model. Epithelial cells were isolated with high purity from human endometrial biopsies. When cultured on a biomatrix bed, cells established a polarized monolayer with gland-like invaginations. Cells isolated throughout the menstrual cycle were cultured under serum-free conditions, with or without estradiol, and secretion of tumor-associated epitope TAG-72 was monitored by radioimmunoassay. Under steroid-free conditions, cells exhibited a distinct proliferative interval, followed by the acquisition of TAG-72 epitope secretory capability. Although estradiol had no apparent effect on proliferation or spatial organization of epithelial cells, a striking inhibition of TAG-72 epitope secretion was evident. This observation is believed to represent a direct effect of estradiol on endometrial epithelial cells in this model.

Antigens, Neoplasm↗
PubMed1990

Orosomucoid in human pregnancy serum diminishes bioavailability of the progesterone antagonist RU 486 in rats.

Bioavailability of the progesterone antagonist RU 486 was examined in vivo by measurement of first-pass uptake by hepatic and uterine tissues in rats. Presence of human pregnancy serum or alpha 1-acid glycoprotein (orosomucoid) in injection vehicles diminished uptake of this steroid, which suggests limited bioavailability. These data indicate that elevated human serum orosomucoid levels may account for some failures of RU 486 in early pregnancy termination.

Animals↗