HIV disease and managed care: an overview.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
M D Smith
Publications and source records attributed to M D Smith.
HIV risk adjustment: issues and proposed approaches.
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Chronic Disease↗
Absolute and relative involvement in homicide offending: contemporary youth and the baby boom cohorts.
Recent concerns have been expressed that youths are an increasingly violent segment of U.S. society. This report explores such claims by presenting alternative dimensions with which trends in youth violence can be interpreted. Using Uniform Crime Reports and U.S. Bureau of the Census data for 1958-1993, rates of arrests for murder, taken to represent absolute levels of involvement in this form of violence, are analyzed for trends among 15-to 19-years-olds. Relative involvement, operationalized as the ratio of arrest rates for those aged 15-19 to those of the remainder of the population, is also analyzed for trends. A pronounced upward trend since the mid-1980s in both rates and ratios of arrests for murder is found for ages 15-19, resulting in this group now having the highest levels of absolute and relative involvement in murder arrests of any age category, a distinct departure from previous years. As a context for interpreting these levels, the involvement of current 15- to 19-year-olds is shown to exceed by a considerable margin the involvement of similarly aged cohorts of baby boomers, a youth group formerly the object of considerable public concern. Research is encouraged that addresses the multifaceted sources contributing to this dramatic societal shift in age-related patterns of arrests for murder and, by assumption, involvement in homicide offending.
Adolescent↗
Pharmacodynamics of racemic and S(-)-atenolol in humans.
The cardiovascular actions of racemic atenolol (RSATN) have been well characterized in humans, but the actions of S(-)-atenolol (SATN) when administered alone are unknown. In this study, responses of heart rate (HR) and Doppler-derived aortic blood flow profiles to upright treadmill exercise were compared after oral administration of 50 mg SATN and 100 mg RSATN in eight healthy, adult, male volunteers. After a single-blind, placebo run-in period, subjects were randomly allocated in a double-blind, crossover fashion to receive SATN and RSATN. Each study period was separated by a 7-day washout period. Multiple submaximal exercise tests were performed and data were collected over the 24 hours after each treatment. Both SATN and RSATN significantly (P < .05) blunted peak exercise HR by 38 +/- 3 and 37 +/- 3 beats/min, respectively. Aortic blood flow acceleration measured during peak exercise decreased after SATN and RSATN, by 13 +/- 4 and 13 +/- 3 m/sec2, respectively (P < .05). No difference in hemodynamic effect was observed between treatments. Pharmacodynamic parameters derived from plasma S(-)-atenolol concentration-effect (HR) curves after SATN, RSATN, and total atenolol plasma concentrations after RSATN did not differ significantly. Predicted maximum reductions in heart rate (Emax) and EC50 for S(-)-atenolol after SATN were 39.6 +/- 5.8 beats/min and 38.4 +/- 40.9 ng/ml versus 34.5 +/- 8 beats/min and 25.9 +/- 29.9 ng/ml for RSATN, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Facilitated communication: the effects of facilitator knowledge and level of assistance on output.
Investigated facilitated communication with 10 adults with autism, and specifically examined the effects of facilitator influence and level of assistance as a function of facilitator knowledge of experimental stimuli. Six men and four women with autism served as subjects, ranging in age from 14 years to 51 years of age. Each subject had 6 experimental sessions, 2 with no help, 2 with partial assistance, and 2 with full assistance. Within each session, the facilitator had knowledge of the experimental stimuli in one half of the trials. Results revealed no cases of correct responding independent of facilitator knowledge of correct answers. Additionally, facilitator control was apparent in numerous cases in which typed output matched stimuli to which the facilitator, not the subject, had been exposed. Results suggest that clinical and educational use of the procedure should be curtailed pending further experimental investigation.
Adolescent↗
A nosocomial outbreak due to non-encapsulated Haemophilus influenzae: analysis of plasmids coding for antibiotic resistance.
An outbreak of infections with non-encapsulated Haemophilus influenzae, resistant to ampicillin, chloramphenicol, sulphonamide and tetracycline involved 13 elderly patients and three nurses on acute admission and care of the elderly wards. Thirty-two isolates were found to be indistinguishable on analysis of biotype, antibiogram, serotype and major outer membrane proteins (MOMP). Plasmids could not be identified in the original isolates but after mating with a Rec A H. influenzae recipient, the resultant transconjugates were found to harbour either a 72 kilobase pair (kB) plasmid coding for resistance to chloramphenicol, ampicillin, sulphonamide and tetracycline or a 65 kB plasmid coding for resistance to chloramphenicol, ampicillin and sulphonamide. Both plasmids yielded virtually indistinguishable restriction digest patterns. This suggests that the tetracycline resistance gene (Tc gene) is a non-essential component of one basic plasmid responsible for the multiple antibiotic resistances seen in the strains recovered during the outbreak. This illustrates the value of plasmid profiles to compare strains of non-encapsulated H. influenzae, and suggests that plasmid restriction enzyme analysis is critical.
Aged↗
Dysphoria and immune status in postpartum women.
This study investigated the relationship between psychological factors and circulating immune cell populations in postpartum women. The study group was 75 women who had vaginal deliveries and were free of psychotropic medication. Four days postpartum each subject completed three mood questionnaires, and a small blood sample was taken. All questionnaire scores were shown to be highly inter-correlated and principal component factor analysis revealed a single factor which we term dysphoria. This factor was significantly associated with lower total circulating lymphocyte counts. The effect was strongest for T cells (largely attributable to a reduction in CD4+ ve T helper cells) and weaker for NK cell counts. No evidence was found of a mediating role for serum cortisol although serum cortisol levels were weakly related to immune status. This study has thus demonstrated that changes in the distribution of the lymphocyte pool are associated with relatively minor differences in postpartum affect.
Adolescent↗
Prognostic value of Doppler transmitral flow patterns in patients with congestive heart failure.
OBJECTIVES: This study was designed to determine whether Doppler echocardiographic transmitral flow patterns can predict cardiac mortality in patients with congestive heart failure. BACKGROUND: Previous studies have indicated that Doppler transmitral flow patterns are related to New York Heart Association functional class and exercise capacity in patients with congestive heart failure. However, the prognostic significance of these flow patterns is not known. METHODS: We analyzed the relation of transmitral flow patterns and cardiac mortality in 100 consecutive patients (76 men, 24 women; mean [+/- SD] age 60 +/- 11 years) with congestive heart failure symptoms and left ventricular ejection fraction < 40%. At the time of entry into the study, functional class and ejection fraction by radionuclide angiography were determined, and Doppler echocardiography was performed in all patients. Transmitral flow was obtained from the apical four-chamber view at the mitral annulus level. Measurements included early (E) and atrial (A) filling velocities, E/A ratio and deceleration time of the E wave. The patients were assigned to two groups according to E/A ratio or deceleration time of transmitral flow patterns, or both: a non-restrictive group (42 patients) with E/A < or = 1 or E/A = 1 to 2 and deceleration time > 140 ms, and a restrictive group (58 patients) with E/A > or = 2 or E/A = 1 to 2 and deceleration time < or = 140 ms. RESULTS: Of 100 patients, 26 died during a mean follow-up period of 16 +/- 8 months. The cumulative cardiac mortality rate determined by the Kaplan-Meier method was 14% at 1 year and 35% at 2 years. Cox proportional hazards model analysis revealed that transmitral flow (restrictive vs. nonrestrictive, chi-square 6.99, p = 0.008), patient gender (female vs. male, chi-square 4.59, p = 0.03) and New York Heart Association functional class (IV vs. II, chi-square 3.95, p = 0.05) were significantly related to cardiac mortality in patients with congestive heart failure. Mortality rate in the restrictive group was markedly higher than that in the nonrestrictive group at 1 year (19% vs. 5%, respectively, p < 0.05) and at 2 years (51% vs. 5%, respectively, p < 0.01) by log-rank test. Relative risk for cardiac death was estimated as 4.1 at 1 year and 8.6 at 2 years in the restrictive group compared with the nonrestrictive group. CONCLUSIONS: In patients with congestive heart failure, a restrictive transmitral flow pattern, female gender and advanced functional class are predictive of higher cardiac mortality. The restrictive transmitral flow pattern by Doppler echocardiography is the single best clinical predictor for cardiac death in patients with congestive heart failure.
Aged↗
A simplified method for determining regurgitant fraction by Doppler echocardiography in patients with aortic regurgitation.
OBJECTIVES: This study attempted to develop and validate a simple method for calculating aortic regurgitant fraction by use of pulsed wave Doppler echocardiography. BACKGROUND: Although several investigators have been able to determine aortic regurgitant fraction by Doppler echocardiography, the methods used require accurate determination of the cross-sectional areas of intracardiac sites at which the volumetric flow is calculated. METHODS: Our concept was based on a constant relation that exists between the cross-sectional area of the left ventricular outflow tract and the mitral valve annulus in normal subjects. To verify this, we used Doppler echocardiography to measure the flow velocity integral of the left ventricular outflow tract and the mitral annulus in the apical view in 50 normal subjects (32 men, 18 women, mean age 34 years). RESULTS: Close correlation (r = 0.95) was observed between the flow velocity integral (FVI) of the outflow tract (OT) and that of the mitral annulus (MA): FVIMA/FVIOT = 0.77. Because mitral flow equals aortic flow in normal subjects, the ratio of the cross-sectional area of the mitral annulus to that of the outflow tract was 1/0.77. In patients with aortic regurgitation, the regurgitant fraction (RF) = (Aortic flow-Mitral flow)/Aortic flow = 1-Mitral flow/Aortic flow. Substituting 0.77 for the area component of flow, RF = 1-(1/0.77).(FVIMA/FVIOT). To evaluate the accuracy of this method, we compared the regurgitant fraction derived by Doppler echocardiography with that from catheterization findings in 20 patients with aortic regurgitation (an isolated lesion was found in 14). The regurgitant fraction by catheterization was the difference between total (angiographic) and forward (thermodilution) stroke volumes as a percent of total flow. Good correlation was observed between catheterization and Doppler regurgitant fraction (r = 0.88, SEE 9%, p < 0.01). CONCLUSIONS: Thus, regurgitant fraction can be estimated from Doppler echocardiography in patients with aortic regurgitation by a method that requires only measurements of the flow velocity integral from the mitral annulus and left ventricular outflow tract.
Adult↗
Comparison of two- and three-dimensional echocardiography with cineventriculography for measurement of left ventricular volume in patients.
OBJECTIVES: We compared two- and three-dimensional echocardiography with cineventriculography for measurement of left ventricular volume in patients. BACKGROUND: Three-dimensional echocardiography has been shown to be highly accurate and superior to two-dimensional echocardiography in measuring left ventricular volume in vitro. However, there has been little comparison of the two methods in patients. METHODS: Two- and three-dimensional echocardiography were performed in 35 patients (mean age 48 years) 1 to 3 h before left ventricular cineventriculography. Three-dimensional echocardiography used an acoustic spatial locator to register image position. Volume was computed using a polyhedral surface reconstruction algorithm based on multiple nonparallel, unevenly spaced short-axis cross sections. Two-dimensional echocardiography used the apical biplane summation of disks method. Single-plane cineventriculographic volumes were calculated using the summation of disks algorithm. The methods were compared by linear regression and a limits of agreement analysis. For the latter, systematic error was assessed by the mean of the differences (cineventriculography minus echocardiography), and the limits of agreement were defined as +/- 2 SD from the mean difference. RESULTS: Three-dimensional echocardiographic volumes demonstrated excellent correlation (end-diastole r = 0.97; end-systole r = 0.98) with cineventriculography. Standard errors of the estimate were approximately half of those of two-dimensional echocardiography (end-diastole +/- 11.0 ml vs. +/- 21.5 ml; end-systole +/- 10.2 ml vs. +/- 17.0 ml). By limits of agreement analysis the end-diastolic mean differences for two- and three-dimensional echocardiography were 21.1 and 12.9 ml, respectively. The limits of agreement (+/- 2 SD) were +/- 54.0 and +/- 24.8 ml, respectively. For end-systole, comparable improvement was obtained by three-dimensional echocardiography. Results for ejection fraction by the two methods were similar. CONCLUSIONS: Three-dimensional echocardiography correlates highly with cineventriculography for estimation of ventricular volumes in patients and has approximately half the variability of two-dimensional echocardiography for these measurements. On the basis of this study, three-dimensional echocardiography is the preferred echocardiographic technique for measurement of ventricular volume. Three-dimensional echocardiography is equivalent to two-dimensional echocardiography for measuring ejection fraction.
Adult↗
Effects hypoxia/reoxygenation on intracellular calcium ion homeostasis in ventricular myocytes during halothane exposure.
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Animals↗
Genes regulating glutathione concentrations in X-ray-transformed rat embryo fibroblasts: changes in gamma-glutamylcysteine synthetase and gamma-glutamyltranspeptidase expression.
The concentration of glutathione (GSH) and the expressions of gamma-glutamylcysteine synthetase and gamma-glutamyltranspeptidase (GGT) were assessed in rat embryo fibroblasts (REF) displaying various stages of X-ray-induced transformation. A secondary culture of REF cells was irradiated, and a normal-immortalized cell line (X-REF-23) was isolated. Chronic exposure of X-REF-23 cells to 12-O-tetradecanoyl-phorbol-13-acetate (TPA) yielded cells (X-REF-23-TP) capable of benign tumor formation in nude mice. These cells exhibited GSH concentrations and gamma-glutamylcysteine synthetase heavy subunit mRNA levels that were approximately 50% less than those measured in X-REF-23 cells. Neither X-REF-23 nor X-REF-23-TP cells exhibited detectable GGT mRNA or activity. Administration of 3 Gy of X-rays followed by chronic TPA treatment yielded cells (X-REF-23-TPX) capable of malignant tumor formation in nude mice. These cells expressed GGT mRNA and Concanavalin-A minus GGT activity. One TPX clone (X-REF-23-TPX.1) was chosen for further characterization. Northern blotting of X-REF-23-TPX.1 cells indicated that gamma-glutamylcysteine synthetase heavy subunit mRNA levels were similar to those of X-REF-TP cells. X-REF-23-TPX.1 cells contained nearly the same amount of GSH as X-REF-23 cells. However, the ability of diethylmaleate (DEM) to deplete GSH was diminished in X-REF-23-TPX.1 cells compared with X-REF-23 cells. Furthermore, exposure of X-REF-23-TPX.1 cells to DEM stimulated GSH resynthesis such that the GSH concentration exceeded control values during exposure. The resynthesis of GSH during a DEM exposure was found to be dependent upon the expression of GGT, as demonstrated by inhibition with AT-125. These experiments indicate that ionizing radiation can lead to elevated constitutive expression of GGT in transformed REF cells and that expression of GGT activity was responsible for the increased rate of GSH repletion observed in X-REF-23-TPX.1 cells.
Animals↗
Ceftazidime vs. amoxicillin/clavulanate in the treatment of severe melioidosis.
An open, paired, randomized, controlled trial of high-dose parenteral ceftazidime (120 mg/[kg.d]) vs. amoxicillin/clavulanate (160 mg/[kg.d]) for the treatment of severe melioidosis was conducted in Ubon Ratchatani in northeastern Thailand. Of 379 patients enrolled in the study, 212 (56%) had culture-proven melioidosis; 106 patients were in each treatment group. The overall mortality rate (47%) was similar for both treatment groups. However, 4 of 75 surviving patients in the ceftazidime group compared with 16 of 69 surviving patients in the amoxicillin/clavulanate group were switched to the alternate regimen because of an unsatisfactory clinical response after > or = 72 hours of treatment (P = .004). The overall therapeutic failure rate (i.e., treatment failure or death due to uncontrolled melioidosis) was significantly higher for the amoxicillin/clavulanate group than for the ceftazidime group (P = .02). Clinical and bacteriologic responses for successfully treated patients were similar in both groups, and both treatments were well tolerated. Parenteral amoxicillin/clavulanate is a safe and effective initial treatment, but parenteral ceftazidime remains the treatment of choice for severe melioidosis.
Adolescent↗
The epidemiology of melioidosis in Ubon Ratchatani, northeast Thailand.
BACKGROUND: Melioidosis, or infection with Pseudomonas pseudomallei is an important cause of morbidity and mortality in South East Asia and Northern Australia. The epidemiology of melioidosis in Ubon Ratchatani, Northeast Thailand was studied over a 5-year period from 1987 to 1991. METHODS: Rates and, when possible, the risks of developing melioidosis were calculated. The numerator was the number of culture-proven cases of melioidosis seen in the 1000-bed referral hospital of the province. The denominators were obtained from the population census, a survey of Health, Welfare and Use of Traditional Medicine, and the North Eastern Meterological Centre, Thailand. RESULTS: The average incidence of human melioidosis was 4.4 (95% confidence interval [CI]: 3.8-5.0) per 100,000. The disease affected all ages with the highest incidence in 40-60 years olds. Melioidosis was 1.4 (95% CI: 0.4-5.3) times more common in males than females. The disease showed a significant seasonal variation in incidence, and a strong linear correlation with rainfall (r = 0.7, 95% CI: 0.5-0.9) Adults exposed to soil and water in their work (most were rice farmers) had an increased risk of melioidosis (in the 40-59 year age group, relative risk = 4.1, 95% CI: 2.4-6.9). Most adult patients had an underlying disease (mainly diabetes mellitus) predisposing them to this infection. CONCLUSION: Melioidosis may result from either acute exposure to the organism in the soil and water, or 're-activation' of an asymptomatic childhood infection (by an unidentified possibly infective seasonal cofactor). The results from this analysis are consistent with both hypotheses. Further epidemiological studies are needed to identify risk factors so that optimal strategies for control of melioidosis may be developed.
Adolescent↗
Susceptibility of Pseudomonas pseudomallei to some newer beta-lactam antibiotics and antibiotic combinations using time-kill studies.
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Anti-Bacterial Agents↗
Cirrhosis in patients with rheumatoid arthritis receiving low dose methotrexate.
We describe three patients with RA who developed cirrhosis while taking low dose methotrexate (MTX). This report includes a review of the risk factors for cirrhosis occurring in association with MTX. Two of these patients were part of a prospective study to quantify changes in pericellular and total collagen in 76 patients with RA receiving low dose pulse MTX, giving a point prevalence of cirrhosis of 2.63%.
Aged↗
Further experience with transesophageal echocardiography in the evaluation of thoracic aortic injury.
This prospective study sought to further define the role of transesophageal echocardiography (TEE) in diagnosing thoracic aortic injury. We performed TEE, aortography, or both on 160 consecutive patients suspected of having blunt thoracic aortic injury: TEE correctly identified 14 aortic injuries, of which five were confirmed by aortography, seven at thoracotomy, and two at autopsy. The TEE results were suggestive of but not diagnostic for injury in two additional patients with proven aortic injury, and TEE was otherwise 100% sensitive and specific for aortic injury. Aortograms yielded one false positive result and four false negative results, for a sensitivity of 73% and a specificity of 99%. We conclude that TEE is a rapid, safe, and accurate bedside method for evaluating the heart and thoracic aorta for blunt trauma. Negative or positive TEE results obviate the need for aortography. We recommend that aortography be used when TEE results are equivocal, when TEE is not tolerated or contraindicated, or when other suspected vascular injuries require evaluation by arteriography.
Adult↗
Wavelength-specific upregulation of keratin mRNA expression in response to ultraviolet radiation.
Keratin intermediate filaments are heteropolymers of coexpressed type I and type II protein chains, whose expression is tightly linked to the differentiation status of the keratinocyte. Epidermal basal keratinocytes coexpress keratins K5 and K14, whereas suprabasal keratinocytes downregulate K5 and K14 and begin to coexpress keratins K1 and K10. Using both isotopic and non-isotopic in situ hybridization, we have investigated the changes in expression of the messenger RNA species encoding the K5/K14 and K1/K10 keratin pairs in response to ultraviolet radiation. Here we report that following irradiation, the mRNA species encoding both keratin pairs is upregulated in a wavelength-specific manner, and that the link between the pattern of keratin mRNA expression and the differentiation status of the keratinocyte is disrupted. Forty-eight hours following ultraviolet B exposure, the amount of detectable mRNA encoding all four keratins studied had increased. Following UVA irradiation, the K1 and K10 signal increased to a much lesser extent than following ultraviolet B, whereas no change in the amount of mRNA encoding the K5/K14 pair was observed. Only two samples were examined following ultraviolet C exposure, but in both, increased K5/K14 signal, but not suprabasal K1/K10 signal, was observed. We suggest that the observations reported here may reflect important qualitative changes involved in photoadaptation of the epidermis, and provide further molecular markers of the different biological effects of ultraviolet radiation of different wavelengths.
Adult↗