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Biomedical subjects

T L Hall

Publications and source records attributed to T L Hall.

At least 19 recordsLinked to original sources
PubMed1999

The effect of opioid and acepromazine premedication on the anesthetic induction dose of propofol in cats.

The median effective dosage (ED50) for induction of anesthesia with propofol was determined by using the up-and-down method in 31 unpremedicated cats, in 30 cats premedicated with butorphanol, 0.4 mg/kg body weight (BW), and acepromazine, 0.1 mg/kg BW, intramuscularly, and in 30 cats premedicated with morphine, 0.2 mg/kg BW, and acepromazine, 0.1 mg/kg BW, intramuscularly. The dose required for a satisfactory anesthetic induction in 50% of unpremedicated cats (ED50) was 7.22 mg/kg BW and of premedicated cats was 5.00 mg/kg BW. The reduction in dose was statistically significant in both premedicated groups compared with no premedication. There was no significant difference in ED50 between premedication regimes. Cyanosis was the most common adverse effect observed in all groups following anesthetic induction with propofol.

Acepromazine↗
PubMed1997

The role of cysteine residues in S100B dimerization and regulation of target protein activity.

Previous studies have demonstrated that the two cysteine residues in the calcium-binding protein S100B are required for its extracellular functions. In the present study, a recombinant S100B protein and mutant S100Bs containing one or no cysteine residue(s) have been used to determine the contribution of cysteine residues to S100B dimerization and interaction with the intracellular target proteins aldolase, phosphoglucomutase, and the microtubule associated tau protein. Mutation of C68 to a valine or C84 to a serine, C68 to valine and C84 to serine, or C68 to valine and C84 to alanine did not significantly alter S100B activation of aldolase. However, mutation of C84 to serine resulted in calcium-independent S100B activation of phosphoglucomutase and a loss of S100B inhibition of tau phosphorylation by Ca2+/calmodulin-dependent protein kinase II. The altered functionality of the C84S mutant with phosphoglucomutase and tau was not due to altered physical properties or dimerization state. All of the mutants exhibited heat stability and calcium dependent conformational changes which were identical to recombinant S100B. In addition, S100B proteins containing two, one or no cysteine residues behaved as dimers in size exclusion chromatography experiments in the presence or absence of calcium as well as in the presence or absence of reducing agent. Dynamic light scattering and analytical ultracentrifugation experiments confirmed that dimerization was not affected by calcium or reducing agent. Altogether these results demonstrate that S100B dimerization is not calcium- or sulfhydryl-dependent. In summary, cysteine residues are not necessary for the noncovalent dimerization of S100B, but are important in certain S100B target protein-interactions.

Calcium-Binding Proteins↗
PubMed1997

Extremely low awareness of AIDS, sexually transmitted diseases and condoms among Dai ethnic villagers in Yunnan province, China.

OBJECTIVE: To assess the awareness of AIDS, other sexually transmitted diseases (STDs), condoms, sources of health information and HIV-related societal risks among Dai villagers in southern Yunnan Province, China. SUBJECTS AND METHODS: In November-December 1994, a cross-sectional descriptive study, comprising a questionnaire-based survey and focus group discussions, was conducted in three Dai villages in Mengla county; a total of 177 Dai villagers were interviewed in the survey and eight focus group discussions were held. Ethnographic observations provided a composite picture of HIV risks in the area. RESULTS: Only 18% of respondents had heard of AIDS, and only 25 and 28%, respectively, had heard of STDs or condoms. Furthermore, among these more aware groups, the level of knowledge was low and misconceptions were common. An ability to understand the official language (Mandarin) was the most important predictor of awareness of AIDS, other STDs or condoms. The sources of information in the three Dai villages sampled included TV, videos, radio and magazines, but only TV and videos had a large audience. Even so, these media were mostly in Mandarin and were not used in AIDS education. Travel outside of China was frequent; most villagers (77%) had traveled to Laos and 9% had traveled to Thailand. Societal risks of HIV transmission, such as an increasing incidence of STDs and an active sex industry, were observed in this area. CONCLUSIONS: Dai villagers in southern Yunnan Province had an extremely low awareness and knowledge of AIDS, other STDs and condoms. Given the high mobility of ethnic villagers to neighboring countries in Southeast Asia and the societal risks of HIV transmission in this area, there is an urgent need to provide accessible education about AIDS and other STDs. Suggestions regarding such health education and the implications of HIV policy-making are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1997

HIV/AIDS-related attitudes and practices of hospital-based health workers in Kampala, Uganda.

OBJECTIVE: To assess HIV/AIDS-related attitudes and practices of hospital-based health workers in Kampala, Uganda. METHODS: A cross-sectional study was conducted in Mulago Hospital, the main national referral hospital in Uganda. A total of 155 physicians and nurses completed a brief questionnaire on HIV risk perception, attitudes and practices regarding AIDS prevention education, HIV counseling and testing and care of patients with HIV disease. RESULTS: Twenty-nine per cent of health workers reported never having discussed AIDS prevention with patients, 26% had never referred patients for HIV counseling and 31% had never advised patients suspected of HIV infection to be tested. Frequent explanations for not providing AIDS prevention education included time constraints and/or lack of related knowledge or skills. While 29% perceived recapping needles as involving no risk, activities involving casual contact with patients and condom use for protection against HIV infection were associated with a high perceived risk of HIV transmission, particularly among nurses. Physicians and nurses differed in their HIV/AIDS-related attitudes and practices. The physicians had a more positive attitude towards the care of patients with HIV disease. In addition, 80% of physicians compared to 59% of nurses referred patients for HIV counseling. A similar trend was found for advising patients to obtain HIV testing. CONCLUSIONS: Hospital-based health workers are missing important opportunities for AIDS prevention education with their patients. There are gaps in their knowledge about HIV and related infection control practices. Interventions should address their concerns and barriers to HIV prevention practices.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Adolescent sexuality in Saint Petersburg, Russia.

OBJECTIVES: To describe adolescent knowledge, attitudes and behavior relevant to sexuality and the prevention of AIDS in Saint Petersburg, Russia. SUBJECTS AND METHODS: A cross-sectional descriptive study was designed, taking a random sample of 10th grade students at 14 Saint Petersburg grade schools, which were stratified by socio-economic district. A total of 185 female and 185 male students completed a self-administered 46-item questionnaire, with a response rate of 94%. RESULTS: From the questionnaires, 20% of females and 31% of males reported having had sexual intercourse and 25% of females and 12% of males reported being sexually abused. These adolescents displayed much misinformation about sexual matters and AIDS prevention. Only 25% of the females and 34% of the males believed that condoms should be used just once, and 38% of each sex believed that if washed, they could be used multiple times. Many respondents, especially males, rated their knowledge about sexual matters as high or adequate. Support for sex education was strong, especially among females, and respondents generally saw sex education as improving sexual pleasure. Most information sources about sexual activity were either not considered very credible, or not adequately accessible. CONCLUSIONS: Substantial reported rates of sexual abuse, sexual experience and much misinformation and unwarranted attitudes toward condoms, safer sexual practices and HIV/AIDS suggest the need for vigorous sex education programs for Russian youth. The early and sustained education of girls is especially important. Sex education should be introduced at an early age so that children can be taught how to reduce the risks of sexual abuse, HIV infection and other sexually transmitted diseases, and to improve their sexual experiences as responsible adults.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Neonatal mortality following transfusion of red cells with high plasma potassium levels.

The death of a neonatal infant following cardiac surgery and the transfusion of packed red cells (RBCs) with high plasma potassium levels is reported. The patient had been diagnosed at 2 weeks of age as having multiple cardiac malformations. During cardiopulmonary bypass surgery, multiple units of packed RBCs less than 5 days old were transfused. In response to a "stat" order and after depletion of stock units prepared for neonatal usage, a 32-day-old unit of packed RBCs was issued for transfusion. After approximately 60 mL was rapidly transfused from this unit, the patient experienced cardiac arrest. Serum potassium concentration after transfusion and before death was 8.9 mmol per L. Plasma potassium concentration in the remainder of the transfused packed RBC unit was approximately 60 mmol per L. A model was created to calculate the posttransfusion plasma potassium concentration, and close correlation was found between the model and the observed potassium concentration, which assumes that the potassium load had not yet been distributed to the extravascular and intracellular fluid compartments. It is concluded that the transfusion of relatively large volumes of RBCs be limited to fresh packed RBCs or to packed RBCs that have been saline washed, to minimize the complications of electrolyte disturbances.

Blood Component Transfusion↗
PubMed1992

AIDS education for hospital workers in Manila: effects on knowledge, attitudes, and infection control practices.

OBJECTIVE: To evaluate an AIDS education intervention for health workers in Metro Manila hospitals. METHODS: A randomized controlled education program consisting of lectures, role-plays, posters and pamphlets was delivered to physicians, nurses, laboratory technologists and orderlies in Manila hospitals. Knowledge, attitudes and infection control practices were measured before, immediately after, and 2 months after the intervention. RESULTS: Baseline survey among 641 hospital workers revealed poor knowledge, negative attitudes towards AIDS patients, and inappropriate infection control practices. Immediately after the intervention, there was significant improvement in (1) knowledge scores (8.7-11.2 in the intervention group versus 8.5-9.5 in the control group; range, 0-14), (2) attitude scores (54.4-60.6 versus 54.6-56.8; range, 22-88), and (3) needle-recapping practices (14-43% versus 39-43%) (all P values < 0.001). After 2 months, attitude scores in the experimental group fell to the same level as those of the control group, while improvements in knowledge and needle recapping were largely maintained. Role-playing was considered by the participants to be the most effective component of the intervention. CONCLUSIONS: These results suggest that AIDS training for hospital workers in the Philippines and in similar countries is necessary and can be effective. Ideally, such training should include role-playing and should be ongoing in order to sustain the effect.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Sources of diagnostic error in fine needle aspiration of the thyroid.

Smears obtained from 795 patients with suspicious thyroid nodules by fine needle aspiration (FNA) of the thyroid gland were seen over a 5-year period at the UCLA Center for the Health Sciences. From 72 patients who underwent subsequent surgical excision of their nodules, inadequate or discrepant FNA diagnoses were noticed in 20 cases (27.8%). These errors could be attributed to inadequate material for diagnosis (n = 6), sampling errors (n = 2), and cytodiagnostic errors (n = 12). If the diagnosis of follicular neoplasm was treated as indeterminate for malignancy, the overall efficiency of FNA was 88.9%. All false-negative diagnoses were related to procedure (i.e., inadequate smears or missed sampling of the lesion). The frequency of inadequate smears, in turn, was strongly related to the type of physician performing the aspiration. The frequency was highest among community-based clinicians (32.4%) and lowest among hospital-based cytopathologists (6.4%). With adequate sampling, the finding of 100% sensitivity in the diagnosis of malignant neoplasms by FNA cytology reaffirms its role as the procedure of choice in the initial screening of thyroid nodules.

Adolescent↗
PubMed1989

Discrimination of benign versus malignant mixed tumors of the salivary gland using digital image analysis.

Seven benign and four malignant mixed tumors of the salivary gland, biopsied using fine-needle aspiration, were analyzed using digital image analysis. Mean nuclear form factor, perimeter, and area were significantly increased in malignant cases. Better separation between diagnostic categories, however, was achieved by utilizing the coefficient of variation (CV) within a case rather than mean value. Form factor CV alone divided cases into nonoverlapping diagnostic categories. This quantitative analog of "pleomorphism" provided a useful marker for malignancy in mixed tumors.

Adenoma, Pleomorphic↗
PubMed1989

Peritoneal clearances with different dialysis regimens in children undergoing continuous cycling peritoneal dialysis.

Peritoneal clearances and dialysate protein losses occurring in paediatric patients undergoing different continuous cycling peritoneal dialysis (CCPD) regimens have not been well defined. We, therefore, evaluated 10 children aged 15.8 +/- 2.5 (SD) years who were maintained on home peritoneal dialysis for 20.5 +/- 10 months. All patients had at least 3 months of CCPD. The patients were admitted to the Clinical Research Center for 48 hours and allocated to five different dialysis protocols. In protocol I, the frequency of exchanges was 10 per 10 hours; in Protocol II it was 5 per 10 hours; and in Protocol III it was 3 per 10 hours. Protocol II D and III D had, in addition, a daytime dwell of one-half the night-time volume. A 1.5% glucose dialysate solution was used for night-time dialysis, and 4.25% glucose dialysate solution for the daytime dwell. The mean inflow dialysate volume per exchange was 36.7 +/- 5.6 ml/kg body weight and was constant in each patient for each study protocol. BUN and creatinine clearances for each protocol were calculated and dialysate protein losses were measured. The data indicate that hourly night-time dialysis (Protocol I) provides best solute clearance. A daytime dwell further enhances the total solute clearance and should be used preferably in anuric patients. Residual urine output contributes significantly to the total solute clearance. Protein losses are maximum with low-frequency exchanges and a daytime dwell. No significant differences in the serum albumin concentrations were found during the different protocols; however, the long-term effect of the protein loss on the nutritional status of the patients requires further evaluation.

Activity Cycles↗
PubMed1989

Quadriceps femoris muscle angle: normal values and relationships with gender and selected skeletal measures.

The quadriceps femoris angle ("Q angle") has been implicated as a source of several knee disorders, but values for normal knees have not been adequately documented in the literature. This study was designed to provide clinicians with normal values and information regarding the relationships between Q angle, gender, and selected anatomical measurements. The Q angles of 100 individuals (50 men, 50 women), who had no history of knee disorders, were measured goniometrically. The hip widths and femur lengths of all subjects were measured with calipers. The mean Q angle for women was 15.8 +/- 4.5 degrees and for men was 11.2 +/- 3.0 degrees. Using a point biserial correlation, we found a relationship between gender and Q angle (r = -.517) that remained significant (p less than .01) when the effects of femur length and hip width were controlled. The relationships identified between Q angle and the anatomical measurements were no longer significant when the effect of gender was eliminated. The results substantiate the belief that women have larger Q angles than men, but they fail to provide clinicians with an anatomical explanation or new predictor of Q angle.

Adult↗
PubMed1988

Canonical analysis of cells in normal and abnormal cervical smears.

Over 4,000 cells from 105 normal and 96 abnormal uterine cervical scrapes were prepared according to the UCLA monolayer procedure, stained by a routine Papanicolaou method and visually classified by two cytopathologists and a technologist into seven classes: parabasal, metaplastic, mild dysplasia, moderate dysplasia, severe dysplasia, carcinoma in situ and invasive carcinoma. Canonical analysis was used to correlate effects-coded class membership variables with 23 cell features derived from digital image analysis. In general, nuclear texture measures derived from linear combinations of run-length correlations along with features derived from a Markov transitional probability matrix provided the best predictors of cell class. After cells were divided into benign (moderate dysplasia or less) and malignant (severe dysplasia or worse) groups, discriminant analysis correctly classified 84% of the benign cells and 91% of the malignant cells.

Cell Nucleus↗
PubMed1988

Multifactor analysis of intermediate cells from the uterine cervix. The importance of slide effects on variance components.

The ability to retrospectively examine cytologic material with digital image analysis is often desirable, particularly when long-term follow-up information is available for correlation with cell parameters. In an effort to characterize the magnitude of slide-age and staining-batch effects on cell parameters from digital image analysis, the cell features in 32 Papanicolaoustained cervical smears that varied in age from 10 to 16 years were analyzed. The slides were selected from eight patients sampled on four different occasions approximately one year apart. The findings indicate that the variance of cell features from an intermediate cell population within a slide is somewhat greater than is the variance among slides from the same woman or the variance among women. Aging effects were not detectable. The significant differences observed among replications of slides from the same woman as well as between women with no evidence of cervical disease should caution other researchers to account for this potential source of random error in their statistical models.

Cell Nucleus↗
PubMed1987

Peritoneal kinetics in children undergoing continuous ambulatory/cycling peritoneal dialysis.

We present a report on peritoneal kinetics in children undergoing continuous ambulatory/cycling peritoneal dialysis (CAPD/CCPD). The effect of long-term treatment with CAPD/CCPD, peritonitis episodes, and dialysate inflow volume on peritoneal kinetics in children was evaluated. Peritoneal kinetic studies (PKSs) were performed in 47 pediatric patients at different times following initiation of CAPD/CCPD. In 18 of these patients, PKSs were repeated up to four times with an unchanged dialysate inflow volume after up to 55 months of CAPD/CCPD treatment. The PKS consisted of a 120-minute dwell with a 1.5% dextrose dialysate solution. Peritoneal clearance, dialysance, and dialysate to plasma (D/P) concentration ratios were calculated after 30, 60, and 120 minutes. The results of the serial PKSs demonstrate stable peritoneal creatinine and urea-N clearance, dialysance or D/P concentration ratios. Furthermore, there was no adverse effect of 32 peritonitis episodes. Finally, inflow volumes correlated directly with clearances of creatinine (P less than .01), urea-N (P less than .001), and potassium (P less than .001), and there was an inverse relationship to the D/P concentration ratios of creatinine (P less than .01), urea-N (P less than .01), potassium (P less than .01), and uric acid (P less than .01). Thus, CAPD/CCPD is a useful and effective long-term treatment modality for pediatric patients. Maximal dialysate inflow volumes should be provided to enhance peritoneal kinetics.

Adolescent↗
PubMed1987

Prognostic significance of DNA ploidy and morphometric analyses of adenocarcinoma of the uterine cervix.

In an effort to improve the prognostic accuracy of the histologic criteria used for cervical adenocarcinomas, the nuclear DNA ploidy levels, means and standard deviations of nuclear areas and amounts of lumen and neoplastic tissue were quantitated. Useful thresholds in discriminating recurrent disease, as identified by logistic regression analysis, included a DNA ploidy level of 3.0 N, a percent of lumen of 34.6% and nuclear area mean and standard deviation of 53.1 sq micron and 20.1 sq micron, respectively. These parameters should provide useful guidelines in the visual assessment of histologic features that have prognostic significance.

Adenocarcinoma↗
PubMed1987

Prognosis of moderate dysplasia. Predictive value of selected markers in routinely prepared cervical smears.

Digital image analysis was used to extract features from 1,123 abnormal cells in 23 routinely prepared, Papanicolaou-stained cervical smears. All slides examined had a cytologic diagnosis of moderate dysplasia. Seven slides came from patients who eventually progressed to either a severe dysplasia or carcinoma in situ; the other 16 slides came from patients whose dysplasias regressed without evidence of more serious disease. Linear discriminant analysis correctly classified approximately 73% of the cells from the regression group and 66% of the cells from the progression group. Cell features contributing to the majority of variance in the model were the mean optical density of the nucleus, an autocorrelation measure, the mean optical density of the cytoplasm and the nuclear-cytoplasmic ratio. At the patient level, 13 (81.2%) of the 16 slides from the regression group and 6 (85.7%) of the 7 slides from the progression group were correctly classified. These figures yield a sensitivity of 66.7%, a specificity of 92.9%, a predictive value of a progression prognosis of 85.9% and a predictive value of a regression prognosis of 81.2%. The overall efficiency of the model was 82.6%. These preliminary results should encourage further studies for the identification of markers to indicate which patients are at high risk for progression of their cervical dysplasias.

Analysis of Variance↗