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Biomedical subjects

H M Reid

Publications and source records attributed to H M Reid.

At least 19 recordsLinked to original sources
PubMed2001

Phenotypic alterations in Caki-1 cells as a consequence of TIMP-1 overexpression.

Maintenance of the extracellular matrix (ECM) is important for tissue integrity and cellular physiology. Normal ECM turnover is regulated by a balance between matrix metalloproteinases and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). In metastasis, this balance favours increased ECM degradation. The objective of this study was to determine the effects of TIMP-1 overexpression on the metastatic process. To this end, we stably transfected a renal carcinoma cell line, Caki-1, with TIMP-1, using a pRc/CMV expression plasmid and LIPOFECTAMINE transfection reagent. The resultant clones displayed increased adhesion on the ECM substratum, including collagen type IV and laminin, and altered invasive capacity through fibronectin and Matrigel, dependent upon the level of TIMP-1 expression. These changes were not due to altered integrin expression, as assessed by flow cytometry. As well as protease inhibitory activity, TIMPs can influence cell proliferation and cell survival. The TIMP-1 clones displayed no changes in proliferation under normal growth conditions, compared with Caki-1 cells. However, under reduced serum conditions, the TIMP-1 clones had a greater percentage of cells in both S (P<0.05) and G(2)/M (P<0.005) phases and less cells in G(0)/G(1) (P<0.001) of the cell cycle than Caki-1 cells. The results confirm a dual role for TIMP-1 in invasion and metastasis, and provide further clues behind the molecular mechanisms in these processes.

Blotting, Western↗
PubMed2000

A comparative study of measures to evaluate medical students' performance.

PURPOSE: To assess how new National Board of Medical Examiners (NBME) performance examinations--computerbased case simulations (CBX) and standardized patient exams (SPX)-compare with each other and with traditional internal and external measures of medical students' performances. Secondary objectives examined attitudes of students toward new and traditional evaluation modalities. METHOD: Fourth-year students (n = 155) at the University of California, Los Angeles, School of Medicine (including joint programs at Charles R. Drew University of Medicine and Science and University of California, Riverside) were assigned two days of performance examinations (eight SPXs, ten CBXs, and a self-administered attitudinal survey). The CBX was scored by the NBME and the SPX by a NBME/Macy consortium. Scores were linked to the survey and correlated with archival student data, including traditional performance indicators (licensing board scores, grade-point averages, etc.). RESULTS: Of the 155 students, 95% completed the testing. The CBX and the SPX had low to moderate statistically significant correlations with each other and with traditional measures of performance. Traditional measures were intercorrelated at higher levels than with the CBX or SPX. Students' perceptions of the various evaluation methods varied based on the assessment. These findings are consistent with the theoretical construct for development of performance examinations. For example, to assess clinical decision making, students rated the CBX best, while they rated multiple-choice examinations best to assess knowledge. CONCLUSION: Examination results and student perception studies provide converging evidence that performance examinations measure different physician competency domains and support using multipronged assessment approaches.

Educational Measurement↗
PubMed1998

Adolescent gender differences in HIV-related sexual risk acts, social-cognitive factors and behavioral skills.

Variations in perceived HIV risk, peer and partner social norms regarding safe sex, self-efficacy, outcome expectancies, and risk-reduction skills (condom use competence and safe sex negotiation) based on gender and sexual risk level were assessed among 132 heterosexual, sexually active, inner city adolescents. Lower sexual risk status was significantly associated with positive partner norms toward safer sex and with favorable partner reaction outcome expectancies. Interaction effects between gender and sexual risk level were found. Outcome expectancies related to approval from others for safer sex were lowest for females in the low-risk group and for males in the high-risk group. Females perceived peers as more positive about safer sex practices, while males perceived sexual partners as more positive. Additionally, females had higher self-efficacy for making condom use enjoyable and planning to avoid risk situations, but were less comfortable than males when demonstrating condom skills. Adolescents' HIV prevention programs must be tailored for gender and risk status.

Adolescent↗
PubMed1998

Parent-adolescent conflict and stress when parents are living with AIDS.

Parental perceptions of conflict and stress with their adolescent children are described, and their associations with demographic factors, physical health, and lifestyle are examined. Adolescent-parent conflicts, parenting stress, and parents' health, substance use, and sexual lifestyle were assessed among 151 parents living with AIDS. Parents living with AIDS reported a mean of 3.3 (SD = 1.3) areas of conflict with their adolescents and 1.5 (SD = 1.7) stressful parenting events over the previous 3 months. The parents were very ill, with many physical symptoms and diseases. Simultaneously, substance use was common (17% used daily), but not injection drug use (3.3%). Half had a sexual partner (63% protected their partners by using condoms consistently). Regression analysis revealed that parent-adolescent conflict was significantly associated with high parental drug use; stressful parenting events were significantly related to the lifestyle (high drug use and frequent sex acts) of Latino and African American parents, but not of white parents. Results of the analysis indicate that, in contrast to parents with other illnesses, parent-adolescent conflict and stressful parenting events were not influenced by parents' health status, but were significantly influenced by substance use and sexual lifestyles.

Acquired Immunodeficiency Syndrome↗
PubMed1997

The impact of illness disclosure and custody plans on adolescents whose parents live with AIDS.

OBJECTIVES: To describe the disclosure and custody planning of parents living with AIDS and the impact of these on their adolescents' adjustment. METHODS: An examination of the association of multiple behaviour problems in children and the illness disclosure and custody plans of their parents living with AIDS. RESULTS: Both mothers (87%) and fathers were significantly more likely to disclose their HIV serostatus to adolescents (73%), compared with younger children (23%); only 44% disclosed their illness to all their children; 11% disclosed to none. Most parents (80%) living with AIDS had discussed their custody plans. However, only 30% initiated legal plans, typically for younger children. Adolescents who were informed of their parents' serostatus engaged in more sexual risk acts, smoked more cigarettes, and reported more severe substance use and greater emotional distress than uninformed adolescents. Legal custody arrangements were not associated with adolescent adjustment at recruitment or follow-up. CONCLUSIONS: A longitudinal analysis of the impact on adolescents of the behaviours of parents living with AIDS is needed.

Acquired Immunodeficiency Syndrome↗
PubMed1997

HIV testing, behaviors, and knowledge among adolescents at high risk.

PURPOSE: We examined HIV testing behavior and its predictors among adolescents considered at high risk for HIV. METHODS: Self-reports of HIV testing, knowledge, attitudes, and high-risk acts were examined among 272 adolescents aged 13-23 years (M = 18.7; SD = 2.3) attending community-based agencies that serve youth at high risk for HIV in Los Angeles, New York City, and San Francisco. RESULTS: Evidence of adolescents' risk for HIV is reflected in a rate of 4.8% seropositivity, 24% injecting drug use, a mean of 4.3 (SD = 11.6) sexual partners during the previous 3 months, and 71% condom use during vaginal/ anal sex. HIV testing was common (63%) and often repeated (M = 3.6, SD = 4.0). Knowledge of the meaning and consequences of testing was high (84% correct). Contrary to service providers' expectations, youth were likely to return for their test results (90% returned). Youth who were older, labeled themselves gay or bisexual, lived in Los Angeles or San Francisco, and those who injected drugs were significantly more likely, compared to peers, to get tested for HIV. CONCLUSIONS: These results suggest a need for more detailed observational studies of HIV testing behavior that include evaluation of characteristics of the youth, the testing site, and the attitudes and beliefs of providers offering HIV testing.

AIDS Serodiagnosis↗
PubMed1997

Invasive streptococcal infections. Report of four cases occurring in Trinidad.

Many countries are reporting a resurgence of virulent streptococcal strains but there is little information from the Caribbean. Four cases of severe invasive streptococcal infections, three of them fatal, are reported. The portal of entry was infected scabatic lesions in one patient and infected mosquito bites in another patient who developed cellulitis and gangrene; but no portal of entry was detected in the other patients. Group A beta haemolytic Streptococcus (GAS) was isolated from the blood of three patients, one of them GAS M type 3, which had the genome for streptococcal pyrogenic exotoxins A (SPeA) and B (SPeB). GAS M type 72, which had the genome for SPeB and SPeC, were isolated from the tissues (but not from the blood) of the patient who developed cellulitis and who was the sole survivor. Physicians in the Caribbean must be alerted to the presence of these virulent streptococcal strains, and must be prepared to manage serious invasive disease.

Adult↗
PubMed1991

Audiogenic seizure susceptibility: inhibitory effect of glucose injection is counteracted by prior glucose.

Audiogenic seizure susceptibility was examined in SJL/J mice injected with glucose 15-30 min before priming and/or subsequent tests. The obtained results confirm previous reports that glucose will inhibit seizure activity if given shortly before a test. In addition, it was found that glucose give 2-4 days previously would counteract the inhibitory effect of glucose injected shortly before testing.

Acoustic Stimulation↗
PubMed1991

Recovery of susceptibility following audiogenic seizure in mice.

The rate at which SJL/J mice recover susceptibility following an initial sound-induced seizure was examined. Fewer than 15% of the subjects seized when retested after a 2-min delay, and only 50% reseized after a 10-min delay. The likelihood of a second seizure was enhanced if the initial seizure exhibited a rapid progression to clonus. During the retest, seizures progressed more slowly than during the initial test, which indicates that recovery was not complete even if a second seizure was induced. Finally, recovery of seizure susceptibility was prevented as long as the subject continued to be exposed to intense auditory stimulation following the initial convulsion, an effect previously noted by Alexander and Kopeloff (1980). The findings are discussed in terms of a recently proposed central inhibitory model of the recovery of audiogenic seizure susceptibility.

Acoustic Stimulation↗
PubMed1989

Independence of uniphasic and biphasic audiogenic seizure progressions in mice.

DBA/2J mice were monaurally or binaurally tested for susceptibility to sound-induced seizure. Two seconds following the beginning of running, one group of binaurally tested mice had acoustic stimulation interrupted for 15 s. These mice later seized when the stimulation was readministered. Their seizure progression closely resembled the behavior exhibited by noninterrupted binaurally stimulated mice and did not shift to the biphasic motor pattern of monaurally stimulated subjects. We conclude that the single burst of running of a binaurally tested mouse is qualitatively different from either of the two bursts of running exhibited by monaurally tested mice.

Acoustic Stimulation↗
PubMed1989

Monaural and binaural audiogenic seizures in mice.

The progression of sound-induced seizures was examined in unilaterally or bilaterally sensitized SJL/J mice tested either monaurally or binaurally. An unexpected right-side advantage for becoming susceptible to audiogenic seizure was observed. In addition, two distinct patterns of seizure progression were noted, a uniphasic sequence in which a single burst of running preceded the convulsion and a biphasic pattern with two such bursts. The biphasic progression is viewed to be the result of unilaterally initiated seizures and characteristically reached only a clonic level of severity. Uniphasic seizures are concluded to be the result of bilaterally initiated seizures and, when they occurred after more than 30 s of auditory stimulation, frequently reached a tonic level of intensity. The present results support the view that audiogenic seizures are characterized by precisely timed, sequential processes dependent upon the specific priming and test procedures employed.

Acoustic Stimulation↗
PubMed1989

Presence of a non-HLA B cell antigen in rheumatic fever patients and their families as defined by a monoclonal antibody.

Numerous investigators have suspected that there is a genetic predisposition to rheumatic fever (RF). In this context we have recently produced a series of monoclonal antibodies directed against B cells obtained from RF patients one of which, labeled D8/17, identifies a B cell antigen present in 100% of all RF patients studied. While the highest percentage of positive cells were exhibited by RF probands (33.5% +/- SE), the percentage of cells in unaffected siblings and parents was 14.6 and 13%, respectively. The percentage of positive cells in APSGN probands, unaffected siblings, and parents was 2.96, 3.86, and 2.8%, respectively. A low level of B cells (5-7%) bearing the D8/17 marker was seen in control patients. The segregation pattern of the phenotypes defined by the percentage of D8/17 positive cells within HLA-typed RF families are consistent with an autosomal recessive mode of inheritance not associated with the human MHC system. We postulate that these phenotypes indicate the presence of at least one necessary genetic factor for susceptibility to RF.

Analysis of Variance↗
PubMed1986

Lateralized audiogenic seizure: motor asymmetries exhibited and the effects of interrupted stimulation.

Sensitized SJL/J mice were monaurally tested for susceptibility to sound-induced seizure. The acoustic stimulation was interrupted for 15 s at various points during the biphasic pattern of running which these mice characteristically exhibit before seizing. Asymmetries of run directions and side of fall were noted. In addition, a dramatic reduction in seizure incidence was found when the interruption either extended into the period when the later burst of running would have occurred or began during this running burst. Finally, the results indicate that the latencies to the later running burst and the subsequent seizure are determined at or about the time of the onset of the first burst of running.

Acoustic Stimulation↗
PubMed1978

Discriminative functions of schedule stimuli and memory: a combination of schedule and choice procedures.

Pigeons responded under a combination brief-stimulus schedule and choice procedure. Normally, a fixed-interval schedule was in effect, where completion randomly produced either a brief stimulus or food. Intermittently, this schedule was interrupted by a choice arrangement. Two choice keys were lit, either a short or a long time since a prior event (food or stimulus). One choice response produced food if the time had been short, and the alternate response produced food if the time had been long. Across conditions, the duration of the fixed-interval schedule was varied, the stimuli that comprised the brief-stimulus operation were changed, and the stimuli were presented as paired and nonpaired with food. The focus of the study was the control of both schedule performance and choice responding across conditions. The results showed that choice accuracy was correlated with the degree of fixed-interval curvature, the response pattern of a pause followed by a gradually accelerated rate. As fixed-interval schedule duration was increased, both the degree of fixed-interval curvature and choice accuracy decreased. The particular brief stimulus used affected schedule and choice performance, with a more salient stimulus producing a greater degree of curvature and higher accuracy. Pairing and nonpairing operations produced striking differences in performance with the less salient brief stimulus, but not with the more salient stimulus. The results suggest that brief-stimulus schedule performance may be conceptualized in the context of memory research.

Journal Article↗