Pioneer 10 jovian encounter: radiation dose and implications for biological lethality.

In its recent Jupiter flyby Pioneer 10 passed through a belt of intense particulate radiation. The radiation dose on the outer surface of the spacecraft was at least 4.9 x 10(5) rads from electrons plus 2.9 x 10(6) rads from protons, sufficient to cause significant microbial decontamination. The radiation dose inside Pioneer 10, approximately 2.8 x 10(5) rads, was less likely to cause microbial decontamination but would be lethal to man and to most multicellular biological organisms.

Neonatal morbidity and mortality associated with triplet pregnancy.

OBJECTIVE: To compare neonatal morbidity and mortality in a large cohort of triplet pregnancies with singleton and twin neonates managed at a single tertiary center over a short time. METHODS: Records from all triplet pregnancies managed and delivered from 1992 to 1996 were reviewed for neonatal outcome data. Pregnancies delivered before 20 weeks' gestation and neonates with lethal congenital anomalies were excluded. The comparison group comprised all singleton and twin neonates managed in the same neonatal intensive care unit (NICU) during the same period. RESULTS: During the 5-year period, 55 triplet pregnancies and their resulting 165 neonates were managed and delivered at this center. Their outcomes were compared with those of 959 singleton and 357 twin neonates born at similar gestational ages. The median gestational age at delivery for triplets was 32.1 weeks, and 149 of the 165 infants were admitted. Sixteen triplet neonates were not admitted to our neonatal intensive care unit, 12 because of previable gestational age, three because of stillbirth, and one because of a lethal congenital anomaly. The crude perinatal mortality rate in triplets was 121 per 1000 births, and there was no significant difference in outcome based on triplet birth order. There were no significant differences in survival rates between singleton, twin, and triplet neonates, with an overall neonatal survival of 95%, 95%, and 97%, respectively. The only significant differences in morbidity were an increased incidence of mild intraventricular hemorrhage (relative risk [RR] 6.20; 95% confidence interval [CI] 2.64, 14.61), mild retinopathy of prematurity (RR 20.05; 95% CI 3.59, 111.79), and severe retinopathy of prematurity (RR 46.69; 95% CI 6.25, 348.85) in triplets compared with singletons, and severe retinopathy of prematurity (RR 6.83; 95% CI 1.24, 37.56) in triplets compared with twins. CONCLUSION: When stratified by gestational age, triplet neonates delivered at 24-34 weeks' gestation have similar outcomes as singleton and twin neonates, with the only clinically significant difference being an increased incidence of retinopathy of prematurity in triplets.

Rhesus sensitization and alloimmune thrombocytopenia.

Significant progress has unquestionably occurred in the diagnosis and treatment of fetal and neonatal alloimmune thrombocytopenia. However, fundamental aspects of this disease are still not fully understood, especially those factors that account for the diverse clinical spectrum of this disease. This impacts our ability to counsel patients regarding the ultimate outcome of fetuses affected with AIT. IVIG appears to be a promising treatment for fetuses affected with this disease. In all likelihood, fetuses affected with AIT are at higher risk for serious bleeding complications related to fetal blood sampling procedures, but this risk remains to be further defined.

Mutagenicity of ultrasound in cultured mammalian cells.

Chinese hamster V79 cells were exposed in suspension to 1 MHz continuous wave ultrasound at spatial peak intensities of 7 and 35 W/cm2. Exposure durations were from 10 to 180 sec, so as to encompass the first decade of decreased survival at each intensity. Exposure at 35 W/cm2 resulted in the induction of 6-thioguanine-resistant mutants. The mutation frequency was approximately one-tenth that induced by x rays at similar survival levels. No mutagenesis was observed at 7 W/cm2. Results are consistent with free radical formation as the mechanism responsible for ultrasound-induced mutagenesis.

Oyster-to-oyster variability in levels of Vibrio parahaemolyticus.

This study examined the variability in the levels of total and pathogenic Vibrio parahaemolyticus in individual oysters. Twenty oysters were collected on three occasions (in June, July, and September 2001) from a site near Mobile Bay, Ala. Ten of these oysters were tested immediately, and 10 were tested after 24 h of storage at 26 degrees C. Levels of total and pathogenic V. parahaemolyticus were determined by alkaline phosphatase-labeled DNA probe procedures targeting the thermolabile hemolysin and thermostable direct hemolysin genes, respectively. Similar V. parahaemolyticus levels (200 to 2,000 CFU/g) were found in nearly 90% of the oysters (for all sampling occasions) prior to storage. The log-transformed densities (means +/- standard deviations) of V. parahaemolyticus in oysters immediately after harvest were 2.90 +/- 0.91, 2.88 +/- 0.36, and 2.47 +/- 0.26 log10 CFU/g for June, July, and September, respectively. After storage for 24 h at 26 degrees C, the mean V. parahaemolyticus densities increased approximately 13- to 26-fold. Before storage, pathogenic V. parahaemolyticus was detected in 40% (10 to 20 CFU/g) of the oysters collected in June and July but was not detected in any oysters collected in September. After storage, pathogenic V. parahaemolyticus was detected in some oysters at levels of > 100 CFU/g. These data should aid in the development of sampling protocols for oyster monitoring programs and in the determination of exposure distributions associated with raw oyster consumption.

Real-time PCR quantification of Vibrio parahaemolyticus in oysters using an alternative matrix.

This study examined the relationship between levels of total Vibrio parahaemolyticus found in oyster tissues and mantle fluid with the goal of using mantle fluid as a template matrix in a new quantitative real-time PCR assay targeting the thermolabile hemolysin (tlh) gene for the enumeration of total V. parahaemolyticus in oysters. Oysters were collected near Mobile Bay, Ala., in June, July, and September and tested immediately after collection and storage at 26 degrees C for 24 h. Initial experiments using DNA colony hybridization targeting tlh demonstrated that natural V. parahaemolyticus levels in the mantle fluid of individual oysters were strongly correlated (r = 0.85, P < 0.05) with the levels found in their tissues. When known quantities of cultured V. parahaemolyticus cells were added to real-time PCR reactions that contained mantle fluid and oyster tissue matrices separately pooled from multiple oysters, a strong linear correlation was observed between the real-time PCR cycle threshold and the log concentration of cells inoculated into each PCR reaction (mantle fluid: r = 0.98, P < 0.05; and oyster: r = 0.99, P < 0.05). However, the mantle fluid exhibited less inhibition of the PCR amplification than the homogenized oyster tissue. Analysis of natural V. parahaemolyticus populations in mantle fluids using both colony hybridization and real-time PCR demonstrated a significant (P < 0.05) but reduced correlation (r = -0.48) between the two methods. Reductions in the efficiency of the real-time PCR that resulted from low population densities of V. parahaemolyticus and PCR inhibitors present in the mantle fluid of some oysters (with significant oyster-to-oyster variation) contributed to the reduction in correlation between the methods that was observed when testing natural V. parahaemolyticus populations. The V. parahaemolyticus-specific real-time PCR assay used for this study could estimate elevated V. parahaemolyticus levels in oyster mantle fluid within 1 h from sampling time.

Skinfold measurements in children. A comparison of Lange and McGaw calipers.

Two types of calipers to measure skinfolds have been compared in adults, but the same type of comparison has not been done in a pediatric population who generally would have smaller skinfolds. Biceps and triceps skinfold measurements were made in 240 pediatric patients ranging in age from 2 weeks to 18 years. Skinfold measurements obtained with a McGaw caliper were on the average 12.6 percent lower than those obtained with a Lange caliper on the same patient. Differences between measurements by two investigators using the same caliper on the same patient averaged 20.4 percent for the Lange caliper and 17.6 percent for the McGaw caliper (root mean square differences). We conclude that McGaw and Ross plastic calipers would be an adequate substitute where cost prohibits the use of Lange calipers.

Dosimetric determination of I-131 activity in the treatment of recurrent, nontoxic, multinodular goiter.

Although surgical treatment of nontoxic multinodular goiter remains the most effective therapy, I-131 is a reasonable alternative in cases where thyroidectomy is not appropriate. Selection of I-131 activity in the management of nontoxic multinodular goiter has largely been empirical. The use of dosimetric measurements in guiding I-131 therapy in the treatment of a patient with a recurrent, nontoxic, multinodular goiter is described.

Hematologic changes in mice during and after exposure to severe hypobaric hypoxia.

Exposing mice to an atmospheric pressure of 300 mm Hg for 16 d caused a variety of hematologic effects. Hematocrit increased rapidly in the first 8 d of exposure and slowly in the second 8 d. Reticulocyte counts rose above normal, peaked on Day 8, and then fell rapidly toward the control level. Macrocytic erythrocytes, formed during exposure, remained macrocytic after the termination of exposure and after the loss of their reticulum. The posthypoxic mice proved sensitive for erythropoietin bioassay. Mice injected with normal dog serum showed a significantly higher incorporation of 59Fe than control mice injected with physiologic saline. A reduction of the duration of exposure to 10 d resulted in only a slight decrease in the sensitivity of the mouse bioassay system. However, a 16-d exposure at a pressure of 360 mm Hg resulted in considerably less sensitive bioassay animals.