Internalization, reduced growth, and behavioral effects following exposure to micro and nano tire particles in two estuarine indicator species.

Synthetic rubber emissions from automobile tires are common in aquatic ecosystems. To assess potential impacts on exposed organisms, early life stages of the estuarine indicator species Inland Silverside (Menidia beryllina) and mysid shrimp (Americamysis bahia) were exposed to three tire particle (TP) concentrations at micro and nano size fractions (0.0038, 0.0378 and 3.778 mg/L in mass concentrations for micro size particles), and separately to leachate, across a 5-25 PSU salinity gradient. Following exposure, M. beryllina and A. bahia had significantly altered swimming behaviors, such as increased freezing, changes in positioning, and total distance moved, which could lead to an increased risk of predation and foraging challenges in the wild. Growth for both A. bahia and M. beryllina was reduced in a concentration-dependent manner when exposed to micro-TP, whereas M. beryllina also demonstrated reduced growth when exposed to nano-TP (except lowest concentration). TP internalization was dependent on the exposure salinity in both taxa. The presence of adverse effects in M. beryllina and A. bahia indicate that even at current environmental levels of tire-related pollution, which are expected to continue to increase, aquatic ecosystems may be experiencing negative impacts.

Dried culture spots for Xpert MTB/RIF external quality assessment: results of a phase 1 pilot study in South Africa.

Implementation of Xpert MTB/RIF requires quality assessment. A pilot program using dried culture spots (DCSs) of inactivated Mycobacterium tuberculosis is described. Of 274 DCS results received, 2.19% generated errors; the remainder yielded 100% correct Mycobacterium tuberculosis detection. The probe A cycle threshold (C(T)) variability of three DCS batches was ≤ 3.47. The study of longer-term DCS stability is ongoing.

Genetic evaluation of carcass traits in Simmental-sired cattle at different slaughter end points.

Our objectives were to estimate genetic parameters for carcass traits and evaluate the influence of slaughter end point on estimated breeding values (BV). Data provided by the American Simmental Association were divided into three sets: 1) 9,604 records of hot carcass weight (CW) and percentage retail cuts (PRC), 2) 6,429 records of CW, PRC, and marbling score (MS), and 3) 1,780 records of CW, PRC, MS, fat thickness (FT), and longissimus muscle area (LMA). Weaning weights (WW) from animals with carcass data and from their weaning contemporaries were used. Data were analyzed with a multiple-trait animal model and REML procedures to estimate genetic parameters and BV on an age-, CW-, MS-, or FT-constant basis. The model for carcass traits included fixed contemporary group and covariates for breed, heterozygosity, and slaughter end point and random additive direct genetic and residual effects. Weaning weight was preadjusted for founder effects, direct and maternal heterosis, age of dam, and age of calf. The model for WW included fixed contemporary group and random additive direct genetic, maternal genetic, maternal permanent environment, and residual effects. Heritabilities from data set 1 were 0.34 for CW and 0.25 for PRC on an age-constant basis and 0.25 for PRC on a CW end point. Heritabilities for data set 2 were 0.35, 0.24, and 0.36 for CW, PRC, and MS, respectively, on an age-constant basis. Data set 2 heritabilities were 0.25 for PRC and 0.34 for MS on a CW-constant basis and 0.33 for CW and 0.25 for PRC at a constant MS end point. Heritabilities on an age-constant basis for data set 3 were as follows: CW, 0.32; PRC, 0.09; MS, 0.12; FT, 0.10; and LMA, 0.26. Heritability estimates for data set 3 on a CW-, MS-, and FT-constant basis were similar to those on an age-constant basis. Heritabilities were 0.12 for PRC, 0.12 for MS, 0.14 for FT, and 0.22 for LMA on a CW-constant basis; 0.30 for CW, 0.09 for PRC, 0.10 for FT, and 0.28 for LMA at a constant MS end point; and 0.33, 0.17, 0.13, and 0.29 for CW, PRC, MS, LMA on a FT-constant basis. Genetic correlations among traits varied across groups and end points but suggested that it should be possible to select for improved lean yield without sacrificing quality grade. Correlations were calculated among BV computed at different end points. Adjustment to various end points resulted in some changes in BV and reranking of sires, especially for PRC; however, the number of records available had a larger influence than slaughter end point.

Risk factors for perinatal human immunodeficiency virus transmission in patients receiving zidovudine prophylaxis. Pediatric AIDS Clinical Trials Group protocol 076 Study Group.

OBJECTIVE: To identify modifiable obstetric factors associated with the failure of zidovudine chemoprophylaxis to prevent perinatal human immunodeficiency virus type 1 (HIV-1) transmission. METHODS: We analyzed data from Pediatric AIDS Clinical Trials Group protocol 076, a randomized, double-masked, placebo-controlled trial that demonstrated that a zidovudine regimen could prevent perinatal HIV-1 transmission. We estimated the zidovudine treatment effect using the relative reduction in transmission risk among women randomized to treatment with zidovudine compared with women randomized to receive placebo. Univariate and multivariate statistical analyses were used to assess whether the treatment effect differed in magnitude according to potential antepartum or intrapartum risk factors. RESULTS: In the univariate analysis, the zidovudine treatment effect was found to differ significantly in magnitude according to quartile of maternal weight at the time of study entry (interaction test, P = .03); among women in the heaviest-weight quartile (weight more than 82 kg), there was a 26% relative reduction in transmission risk, compared with a 79% relative reduction among the other three quartiles (interaction test, P = .05). In the zidovudine treatment group, women who transmitted HIV-1 were significantly more likely than nontransmitters to have had antepartum procedures or conditions associated with increased risk of fetal exposure to maternal blood or cervicovaginal secretions (43% compared with 19%, P = .04). In the multivariate analysis, adjustment for the plasma HIV-1 RNA level and CD4+ cell percentage did not eliminate the differential treatment effect according to these factors. CONCLUSION: High maternal weight and conditions associated with fetal exposure to maternal blood or cervicovaginal secretions may diminish the efficacy of zidovudine chemoprophylaxis.

Safety of the maternal-infant zidovudine regimen utilized in the Pediatric AIDS Clinical Trial Group 076 Study.

OBJECTIVE: To determine the safety of the zidovudine (ZDV) regimen utilized in the Pediatric AIDS Clinical Trial Group (ACTG) 076 study. DESIGN: ACTG 076 was a randomized, double-blind, placebo-controlled trial which demonstrated that a ZDV regimen could prevent mother-to-child HIV-1 transmission. Infants were followed through 18 months of age and women were followed through 6 months postpartum. METHODS: Maternal complications, pregnancy outcomes, growth and development of the uninfected infants, and HIV-1 disease progression in the women were monitored prospectively. RESULTS: Maternal therapy was well tolerated. There was no serious pattern of adverse pregnancy outcomes associated with ZDV use. Amongst the ZDV-exposed infants, the only recognized toxicity was anemia within the first 6 weeks of life; the risk for anemia was not associated with premature delivery, duration of maternal treatment, degree of maternal immunosuppression, or maternal anemia. ZDV treatment was not associated with an increased incidence of newborn structural abnormalities. At 18 months of age, uninfected infants did not differ in growth parameters or immune function. No childhood neoplasias were reported in either group. In the women, at 6 months postpartum, there were no differences in clinical, immunologic, or virologic disease progression. CONCLUSION: There were no identified problems that would alter current recommendations for the routine use of ZDV for the prevention of mother-child HIV-1 transmission.

Performance and genetic trends in purebred Simmental for regions of the United States.

A study was conducted to determine whether differences in regional performance could be attributed to different selection goals among Simmental breeders. Using data obtained from the spring 1993 National Simmental Cattle Evaluation, breeders were identified by region of the country as defined by the American Simmental Association: South Central (SC), North Central (NC), West (W), and East (E). Animals included in the analysis were at least 87.5% Simmental and from breeders who recorded data every year from 1978 to 1991. The number of breeders and animals from each region were 154 and 62,830 in the SC, 260 and 139,053 in the NC, 102 and 57,434 in the W, and 143 and 39,786 in the E. Phenotypic, genetic, and environmental trends were estimated in each region for birth weight (BWT), weaning weight (WWT), and postweaning gain (PWG). The growth genetic trends were increasing at similar rates in the regions over time. For maternal milk (MMK), breeders in the NC and W decreased maternal breeding value slightly compared to SC and E breeders. For BWT, the average environmental trends ranged from .0 kg/yr in the SC to .11 kg/yr in the NC. The regional WWT environmental trend ranged from 1.4 to 2.2 kg/yr. The environmental trends for PWG varied from -3.1 kg/yr in the SC to .3 kg/yr in the W. Selected parents had higher estimated breeding values than their birth year averages each year for BWT, WWT, and PWG. The average maternal breeding values for selected parents were essentially zero compared with their birth year averages.(ABSTRACT TRUNCATED AT 250 WORDS)

Marshall-Smith syndrome: further delineation.

We have reported a case of the Marshall-Smith syndrome, a condition characterized by accelerated bone maturation, dysmorphic features, respiratory compromise, failure to thrive, neuro-developmental abnormalities, and death in early infancy. Early evaluation of upper airway obstruction in these children may be important in prolonging life. Although the prognosis has been poor to date, early recognition and aggressive multi-disciplinary therapy may permit further investigation into the cause and appropriate management of this disorder.

Infantile myofibromatosis: the most common fibrous tumor of infancy.

We describe the clinical courses of four infants with infantile myofibromatosis (IM). This entity is a mesenchymal disorder of early infancy characterized by the formation of tumors in skin, muscle, viscera, bone, and subcutaneous tissues. Previously known as congenital generalized fibromatosis, IM was formerly thought to be a rare condition that was frequently fatal. The majority of the 170 affected patients we describe have been diagnosed since 1980. Furthermore, the mortality rate for these patients is less than 15%. Our review includes the clinical manifestations, as well as histopathologic features, and discusses the prognosis in affected infants. We found that infants with solitary lesions or multiple lesions without visceral involvement generally have a benign course. However, in patients with the multicentric form of the disorder and visceral involvement, 73% have died. Because the lesions may not be easily discernible and most spontaneously resolve, the condition is underdiagnosed and underreported. IM is the most common fibrous tumor of infancy and must be considered when evaluating children who present with either solitary or multiple tumors, particularly during the neonatal period.

A categorical course curriculum for radiology residencies.

A categorical course curriculum was introduced at Brooke Army Medical Center to focus the content of daily conferences and lectures according to radiology subspecialties. Our goal was to improve the traditional uncoordinated conferences and apprenticeship approach to resident learning. After one-year's experience, resident performance has improved, and residents and staff greatly prefer this style of teaching. The format has been adopted.

Effects of using sires selected for yearling weight and crossbreeding with beef and dairy breeds: birth and weaning traits.

Data consisting of 948 calf records collected from 1978 to 1982 were analyzed to determine the effects of breeding methods used to improve commercial herds genetically on birth and weaning traits. Four distinct groups were used in the project: Group 1 (G1), an unselected, random mating Hereford control line; Group 2 (G2), a Hereford group using sires selected for yearling growth; Group 3 (G3), a rotational cross with Angus, Hereford, Charolais and Simmental breeds; and Group 4 (G4), a rotational cross with Angus, Hereford, Simmental and Holstein-Friesian breeds. Traits analyzed were birth weight (BW), calving difficulty (CD), percent assisted births (%AB), percent born alive (%BL), preweaning average daily gain (PWDG), relative growth rate (RGR), weaning weight (WWT) and percent weaned (%WND). The use of high yearling weight sires in G2 increased calf size (P less than .01) at birth and weaning by 8.9 and 28.1 kg, respectively, along with increased CD (P less than .01). Use of rotational crossbreeding systems increased calf size and growth from birth to weaning (P less than .01), but decreased CD and %AB (P less than .01) by .17 units and 13.5%, respectively. Including Holstein-Friesian in G4 resulted in further increases in preweaning growth (P less than .01) and calving ease was improved without affecting BWT compared with G3.