Rates of tuberculosis infection in healthcare workers providing services to HIV-infected populations. Terry Beirn Community Programs for Clinical Research on AIDS

OBJECTIVE: To assess the prevalence of tuberculosis (TB) or a positive skin test in healthcare workers (HCWs) providing services to human immunodeficiency virus (HIV)-infected individuals and to determine prospectively the incidence of new infections in this population. DESIGN: This prospective cohort study enrolled 1,014 HCWs working with HIV-infected populations from 10 metropolitan areas. Purified protein derivative (PPD) tuberculin skin tests were placed at baseline and every 6 months afterwards on those without a history of TB or a positive PPD. Demographic, occupational, and TB exposure data also were collected. SETTING: Outpatient clinics, hospitals, private practice offices, and drug treatment programs providing HIV-related healthcare and research programs. PARTICIPANTS: A voluntary sample of staff and volunteers from 16 Community Programs for Clinical Research on AIDS units. RESULTS: Factors related to prior TB or a positive skin test at baseline included being foreign-born, increased length of time in health care, living in New York City, or previous bacille Calmette-Guerin vaccination. The rate of PPD conversion was 1.8 per 100 person years of follow-up. No independent relation was found between the amount or type of contact with HIV-infected populations and the risk of TB infection. CONCLUSION: These data provide some reassurance that caring for HIV-infected patients is not related to an increased rate of TB infection among HCWs in these settings.     

Protein farnesyltransferase

Changes in mice haemopoietic cellular populations and in the radiosensitivity of CFU-C and BFUe progenitors cells were determined in vivo for mixed field radiations composed of a gamma-ray component and a neutron component. Five Dgamma/Dtotal ratios (gamma-rays over total dose ratios, quoted as tau in this report) were obtained (tau = 0.95, 0.83, 0.67, 0.33 and 0.09). Myelogram changes were enlarged with the increase of the neutron component. Radiosensitivity of the two progenitor cell lineages were increased with lower tau values (excess of neutrons). The radiosensitivity of haemopoietic progenitor cells exposed in vivo varies with the ratio of the high- and low-LET components in the mixture. The D0 value varied from 3.3 +/- 0.22 to 0.85 +/- 0.04 Gy with the decrease of tau for CFU-C and from 2.08 +/- 0.22 to 0.64 +/- 0.07 Gy for BFUe. The obtained relative biologic efficiency (RBE) varied from 1.2 +/- 0.08 to 4.7 +/- 0.24 for CFU-C and from 1.1 +/- 0.1 to 3.6 +/- 0.16 for the BFUe. The relation between RBE and tau could be somewhat non-linear for CFU-C and seems to be close to linear for BFUe. The higher is the neutron component, the higher is the radiosensitivity. These results indicate that variations of the quality of the mixed field in the haemopoietic local territory are of great importance in terms of radiation damage and cell killing as well as in terms of the ability to restore the haemopoietic system.     

Zygomatic salivary cyst with mucocele formation in a cat

An eight-year-old neutered male domestic shorthair cat had a zygomatic salivary cyst with associated mucocele formation. A fluctuating swelling developed ventral to the right eye, causing bulging of the lower eyeild, and a corresponding swelling was present in the caudal vestibule of the oral cavity. Cytological examination of the fluid obtained from aspiration of the swelling was consistent with the appearance of saliva. A tentative diagnosis of zygomatic salivary mucocele was made. Surgical exploration and resection of the swelling demonstrated the presence of a multilobular cystic zygomatic salivary gland. The histopathological appearance of the resected tissue was interpreted as an inflammatory reaction to mucus derived from a multilocular salivary cyst.     

Role of substance P in pressor response of central amygdaloid nucleus to glutamate

Substance P (SP)-immunoreactive cells and the axon terminals are widely distributed in the central amygdaloid nucleus (AC) and its important projection areas. The present study showed that (1) Excitation of the AC by glutamate (Glu) or injection of SP into the AC projection areas: locus coeruleus (LC), nucleus parabrachialis (NPB), periaqueductal gray matter (PAG) or lateral hypothalamus-perifornical region (LH/PF), all elicited pressor response. (2) Preinjection of DPDPDT (a SP antagonist) into bilateral LC, NPB, PAG or LH/PF could attenuate the AC pressor response to Glu. (3) Intra-RVLM (rostral ventrolateral medulla) preinjection of either phentolamine, propranolol or atropine (but not GDEE, a Glu antagonist) could also reduce the AC pressor response. Taken together with our previous findings that the alpha-, beta-, M-receptors in RVLM mediated the pressor response to LC excitation, alpha-receptors mediated the NPB pressor response, alpha- and beta-receptors mediated the PAG pressor response; these results indicate that the SPergic projections of the AC not only directly act upon the brainstem pressor areas (LC, NPB, PAG)-RVLM system, but also indirectly via the LH/PF act upon the brainstem pressor areas-RVLM system to induce the pressor response.     

Summary measures of the insulin resistance syndrome are adverse among Mexican-American versus non-Hispanic white children: the Corpus Christi Child Heart Study

BACKGROUND: Mexican-American (MA) adults are known to have a greater burden of diabetes and insulin resistance than non-Hispanic white (NHW) people. In this report, we examined data obtained from MA and NHW third-grade children for evidence of a pattern consistent with the insulin resistance syndrome. In addition, we developed two summary measures characterizing insulin resistance syndrome to compare measures of this syndrome among our population. METHODS AND RESULTS: Data regarding fasting insulin, triglycerides, HDL cholesterol, systolic blood pressure, and body mass index (BMI) were available for 403 third-grade children. Median levels of insulin and glucose were significantly higher in MA boys and girls than in NHW boys and girls. Risk factors characterizing insulin resistance, including levels of insulin, triglycerides, systolic blood pressure, HDL cholesterol, and BMI were categorized as above or below the total population median. MA children were more likely than NHW children to have three or more adverse risk factors (55% versus 37%). When risk factors were converted to Z scores, and the five Z scores were summed for each individual, MA boys and girls had higher mean scores than NHW boys and girls (means for boys, 0.65 versus -0.97, P<.0001; girls, 0.52 versus -0.30, P<.04). Principal components analysis was used to create a summary score or index representing the insulin resistance syndrome. This summary score was significantly higher among MA boys and girls than NHW boys and girls (means for boys, 0.34 versus -0.72, P<.0001; girls, 0.35 versus -0.04, P=.056). CONCLUSIONS: Our results support the hypothesis that MA children exhibit a greater degree of the insulin resistance syndrome than NHW children, especially among boys. We conclude that some of the factors responsible for the increased risk of NIDDM seen among MA adults are demonstrable in childhood.     

Predicting microbial growth: graphical methods for comparing models

Some simple computer-based graphics were used to compare different models predicting microbial growth responses of salmonellae to three factors (pH, sodium chloride concentration and incubation temperature). Simple linear regression, contour and three-dimensional surface plots all revealed gross differences between the predicted growth parameters from different growth models. Regression and contour plots were found to be more sensitive to small differences in surface topography, but three-dimensional surface plots provided a good overview.     

Impedance Spectroscopy Study of Sintering in Bi-Doped ZnO

Solid- and liquid-state sintering kinetics in the (1 – x)ZnO-xBi₂O₃ system with 0 ≤ x ≤ 0.05 over the range 600 ≤ T (°C) ≤ 1100 were investigated by impedance spectroscopy. Compositions with x < 0.002 retarded sintering, whereas compositions with x ≥ 0.004 accelerated sintering above the eutectic temperature of 740°C. The results could be interpreted in terms of limited solid solubility of Bi₂O₃ in ZnO ( x ≃ 0.004 ± 0.002), solid-state sintering in the subsolidus, and liquid-state sintering above the solidus. A phase diagram for the ZnO-rich end of the system is proposed, based on these results.