Premature or Just Small? Training Guatemalan Birth Attendants to Weigh and Assess Gestational Age of Newborns: An Analysis of Outcomes

We describe Guatemalan birth attendants’ identification of vulnerable newborns, their evaluation of gestational age and anthropometry, and the validity of the Capurro and New Ballard newborn gestational age assessment methods. We interviewed 49 birth attendants and trained 10 of these women to assess 63 newborns. The Capurro and Ballard methods were correlated (Spearman rho = .75, p < .001) and showed agreement (Bland-Altman plot, difference and bias, ?0.33 ± 1.3 weeks). Prematurity was estimated at 27% (Ballard) and 24% (Capurro); low birth weight (LBW) was 30%. Capurro provided a simplified, equivalent estimate of gestational age compared with New Ballard that could be used by birth attendants.     

Repeatability of near visual acuity measurement at high and low contrast

Purpose: The aim of this study was to determine the repeatability of high‐ and low‐contrast visual acuity (VA) measurements at near. Methods: Fifty‐five normal subjects were recruited. Inclusion criteria included visual acuity of at least 0.00 logarithm of minimum angle of resolution (logMAR) on each eye at distance. One eye was selected for this study, either the one with a better acuity or randomly chosen if there was no difference between the two eyes. Near VA was measured in a random order with the PolyU high‐contrast (PolyU‐HC), the PolyU low‐contrast (PolyU‐LC), the Precision high‐contrast (P‐HC) and the Precision low‐contrast (P‐LC) charts at 400 mm. Measurements were repeated after one to two weeks. Repeatability was presented using the 95% limits of agreement between visits. Results: The between‐visit repeatability was ±0.063 logMAR for high‐contrast and ±0.141 for low‐contrast using the PolyU charts. The between‐visit repeatability was ±0.120 logMAR for high‐contrast and ±0.110 for low‐contrast using the Precision charts. Seventeen subjects had high‐contrast VA better than ‐0.10 logMAR using Precision chart, which could not be measured by PolyU chart. The mean difference between high‐ and low‐contrast VA was 0.108 from the Precision charts (median difference of 0.10 or one line). Conclusions: The Precision charts could measure high‐contrast near VA to threshold level. Practitioners should be aware of a VA difference of more than one line in repetitive measurement, at both high and low contrast. A difference in near high‐ and low‐contrast VA of more than one line may warrant further investigation.     

Depsides as non-redox inhibitors of leukotriene B(4) biosynthesis and HaCaT cell growth, 2. Novel analogues of obtusatic acid

Aseries of obtusatic acid analogues has been synthesized and evaluated as inhibitors of leukotriene B(4) (LTB(4)) biosynthesis and as antiproliferative agents. The 4-O-benzylated and the 4-O-demethylated congeners were the most potent inhibitors of LTB(4) production of the depside class of compounds, with IC(50) values in the submicromolar range. Furthermore, these compounds do not function as redox-based inhibitors because they were not reactive against a stable free radical, 2,2-diphenyl-1-picrylhydrazyl, and did not produce appreciable amounts of deoxyribose degradation as a measure of their potency to generate hydroxyl radicals. Some obtusatic acid congeners were also potent inhibitors of keratinocyte growth. Growth inhibition was not mediated by damage to the cell membrane, as the activity of lactate dehydrogenase released from the cytoplasm was in the control range.     

Occurrence of primary cancers in association with multiple myeloma and Kaposi's sarcoma in the United States, 1973-1995

The causes of multiple myeloma (MM) are obscure, but a laboratory association was recently reported between MM and human herpesvirus 8 (HHV-8), the probable etiologic agent of Kaposi's sarcoma (KS). Although there has been some additional laboratory corroboration, most laboratory studies have found no association between MM and HHV-8. We looked for indirect evidence of an HHV-8/MM association by evaluating whether MM is associated with KS in the United States. Cancer incidence and survival data were obtained from the Surveillance, Epidemiology, and End Results (SEER) program for the years 1973-1995. Strength of association was assessed for a number of cancer pairs using standardized incidence ratios (SIRs) (observed/expected double cancers). KS was strongly associated (SIR > 15) with non-Hodgkin's lymphoma and anal cancer, was modestly associated (2.5 < SIR < 5.5) with MM, Hodgkin's disease, and testicular cancer and was not significantly associated with 6 other cancers. Besides being associated with KS, MM was weakly associated (1.7 < SIR < 2.3) with Hodgkin's disease and testicular cancer. The SIRs for 7 other cancers paired with MM were all less than 1.6. Factors that might be responsible for the KS/MM association include MM-related immune dysfunction, HIV and HHV-8, but the role of these factors cannot be directly assessed through the SEER database. Although we cannot rule out the possibility that HHV-8 is linked to a small proportion of MM cases, the modest KS/MM association is evidence that the vast majority of MM cases are not likely to be associated with HHV-8.     

Half-life of polybrominated biphenyl in human sera.

Polybrominated biphenyl (PBB), a flame-retardant material, was introduced into the food chain in Michigan in 1973 due to a manufacturing and distribution mistake. Following public concern about the long-term health effects of PBB in humans, a cohort of PBB-exposed Michigan residents was assembled in 1975. We initiated this study to determine the half-life of PBB in human sera and to understand how continued body burden relates to the possible adverse health consequences of PBB exposure. To determine the half-life, eligible persons were selected from the cohort if they had at least two PBB measurements 1 year apart and had an initial level > or = 20 pbb. There were 163 persons who met the criteria with a median PBB level of 45.5 ppb. The estimated half-life is 10.8 years (95% CI, 9.2-14.7 years). The body burden of PBB in exposed persons will decrease only gradually over time. For persons with an initial level of 45.5 ppb of PBB, it will take more than 60 years for their PBB levels to fall below the current level of detection of 1 ppb.     

Tests of trait-haplotype association when linkage phase is ambiguous, appropriate for matched case-control and cohort studies with competing risks

The impact of competing risks on tests of association between disease and haplotypes has been largely ignored. We consider situations in which linkage phase is ambiguous and show that tests for disease-haplotype association can lead to rejection of the null hypothesis, even when true, with more than the nominal 5 per cent frequency. This problem tends to occur if a haplotype is associated with overall mortality, even if the haplotype is not associated with disease risk. A small simulation study illustrates the magnitude of bias (high type I error rate) in the context of a cohort study in which a modest number of disease cases (about 350) occur over time. The bias remains even if the score test is based on a logistic model that includes age as a covariate. For cohort studies, we propose a new test based on a modification of the proportional hazards model and for case-control studies, a test based on a conditional likelihood that have the correct size under the null even in the presence of competing risks, and that can be used when haplotype is ambiguous.     

Residual spatial correlation between geographically referenced observations: a Bayesian hierarchical modeling approach

BACKGROUND: Analytic methods commonly used in epidemiology do not account for spatial correlation between observations. In regression analyses, this omission can bias parameter estimates and yield incorrect standard error estimates. We present a Bayesian hierarchical model (BHM) approach that accounts for spatial correlation, and illustrate its strengths and weaknesses by applying this modeling approach to data on Wuchereria bancrofti infection in Haiti. METHODS: A program to eliminate lymphatic filariasis in Haiti assessed prevalence of W. bancrofti infection in 57 schools across Leogane Commune. We analyzed the spatial pattern in the prevalence data using semi-variograms and correlograms. We then modeled the data using (1) standard logistic regression (GLM); (2) non-Bayesian logistic generalized linear mixed models (GLMMs) with school-specific nonspatial random effects; (3) BHMs with school-specific nonspatial random effects; and (4) BHMs with spatial random effects. RESULTS: An exponential semi-variogram with an effective range of 2.15 km best fit the data. GLMM and nonspatial BHM point estimates were comparable and also were generally similar with the marginal GLM point estimates. In contrast, compared with the nonspatial mixed model results, spatial BHM point estimates were markedly attenuated. DISCUSSION: The clear spatial pattern evident in the Haitian W. bancrofti prevalence data and the observation that point estimates and standard errors differed depending on the modeling approach indicate that it is important to account for residual spatial correlation in analyses of W. bancrofti infection data. Bayesian hierarchical models provide a flexible, readily implementable approach to modeling spatially correlated data. However, our results also illustrate that spatial smoothing must be applied with care.