Quantitative analysis of associations between birth defects and suspected human teratogens.

Case series of infants with certain birth defect patterns and putative teratogenic exposures should be interpreted with caution since the presence of birth defects and the exposure among the same infants could be entirely due to chance. In the absence of other epidemiologic data, the plausibility for a causal association is strengthened by 1) rarity of the defect pattern, 2) rarity of the exposure in the population, 3) small source population, 4) short time period for the study, and 5) biologic plausibility for the association. These concepts are illustrated using case reports of putative teratogenicity of cocaine and etretinate. In the presence of epidemiologic data, the concept of attributable fraction in exposed (AFE) can be used to evaluate the likelihood that the defect pattern among infants with a particular exposure is attributable to the exposure. This quantity is related to the strength of the epidemiologic association between the defect pattern and the exposure, as measured in terms of relative risk R (or odds ratio), and is equal to (R-1)/R. Even for strong teratogens such as maternal diabetes and isotretinoin, where R is about 7, in more than 14% (1-AFE) of exposed infants with birth defects, the pattern of defects is not attributable to the exposure. Furthermore, AFE can be used to "correct" crude measures of sensitivity (the proportion of exposed malformed infants with a defect pattern attributable to the exposure) and positive predictive value (the proportion of malformed infants who have the exposure and have the defect pattern attributable to the exposure).(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunofluorescent vascular pattern due to EVI antibody of Chagas' disease. Its diagnostic value.

One hundred fifty-six of 1,250 sera from patients with presumed connective tissue and related diseases showed vascular staining on mouse liver cryostat sections when they were routinely checked for antinuclear factor by the indirect immunofluorescence test. In a third of the cases, the vascular immunofluorescent pattern was given by the EVI antibody reacting with the plasma membrane of striated muscle fibers and endothelial cells, as has been recently described to occur in Chagas' disease. This led to the detection of previously unsuspected Trypanosoma cruzi infection in 67.8% of the serum samples in which the EVI antibody was detected after observation of a positive vascular pattern with mouse liver cryostat sections. On the other hand, no significant relationship between Chagas infection and sera with other anti-striated-muscle immunofluorescent patterns that also showed a vascular staining on mouse liver cryostat sections was established. Consideration of the vascular pattern observed with the EVI antibody on mouse liver cryostat sections can be helpful in detection of previously ignored T. cruzi infection in patients who have connective-tissue diseases and related conditions. This is of interest in view of the fact that anergic immunodepressive therapy, often used in these patients, significantly alters the host-parasite relationship and may lead to severe dissemination of the parasite.     

Body composition measures from underwater weighing and dual energy X-ray absorptiometry in black and white girls: A comparative study

The purpose of this study was to compare estimates of body composition in two ethnic groups, 31 black and 38 white girls 10 through 16 years of age, to establish accurate and precise laboratory standards for field measures of body composition in the NHLBI Growth and Health Study HC 55025. The dual energy X-ray absorptiometry (DXA) measures of fat free mass (FFM) and % body fat (%BF) were made using Hologic QDR-1000/W. Corresponding values of FFM and %BF from underwater weighing (UWW) were determined using the two-component model of Siri, and these were corrected using the model of Lohman for white girls only. In the comparison of the different models and methods, the two-component model overestimated FFM compared to estimates from DXA for black girls, as did the corrected Lohman model for white girls. The two-component model significantly overestimated %BF in both white and black girls compared to corresponding estimates from DXA. The ratio of bone mineral content (BMC)/FFM affected the degree of %BF differences in black girls but not in white girls. Also, as the density of FFM increased or approached adult status in black girls (BMC/FFM increased), differences between the two-component model and estimates from DXA decreased. In both groups of girls, the relationship of %BF from UWW and DXA are a function of the level of body fatness. DXA values of %BF are greater than those from UWW under about 24% body fat, but the converse occurs above 25% body fat. The inability of UWW using the two-component model to account for the body composition in these girls can be corrected in part by measuring the variables for a multicomponent model or more easily by using DXA estimates of body composition. © 1994 Wiley-Liss, Inc.     

Emergency treatment and long-term follow-up of posterior urethral valves

Posterior urethral valves have a broad spectrum of clinical severity determined by the degree and reversibility of the long stepwise sequence of secondary pathology. Neonatal azotemia and severe bilateral reflux are particularly important negative prognostic factors. In the mild cases, valve ablation with or without delayed reconstruction is good therapy. In the very severe cases, our interpretation of all the clinical and experimental information now available suggests that the time interval and the level of decompression are extremely important. Achievement of consistent low caliceal pressure without stasis and infections should be achieved as soon as possible. We do not agree with the philosophy of "valve ablation and wait and see" for secondary reconstruction as applied to the severe cases. An analogous philosophy would be treating all respiratory infections as upper respiratory infections and applying aggressive appropriate therapy for pneumonia only if the patient does not respond clinically. However, all controversy aside, the management of neonatal infants with posterior urethral valves remains a difficult and challenging problem for us all. The real challenge will be to improve published management results to the point that the family faced with decisions regarding an in utero diagnosis of posterior urethral valves will have enough hope to continue the pregnancy.     

Aberrant cervical thymus in an infant: an unusual cause of stridor

We report an 8-month-old infant presenting with stridor caused by a nonpalpable neck mass discovered at imaging and surgery. The diagnosis of aberrant thymic tissue was confirmed at histopathology. The authors reviewed the literature and discuss the embryology, imaging findings and differential diagnosis of this rare disorder. Received: 1 July 1999; Revised: 3 September 1999; Accepted: 6 September 1999     

The challenges of androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS) is an X-linked recessive genetic syndrome that occurs as result of an androgen receptor mutation; it affects the normal masculinization process in chromosomal male patients. More than 900 androgen receptor mutations that can lead to AIS have been identified. The complete androgen insensitivity is characterized by a total lack of response to androgens, usually in patients with 46XY karyotype but with feminine phenotype. Primary amenorrhoea and inguinal swellings in female patients are the main signs that could raise suspicion for this syndrome. Patients with partial androgen insensitivity have ambiguous genitalia at birth and gynecomastia during puberty, whereas those with mild androgen insensitivity present a normal male phenotype but altered spermatogenesis during adulthood and pubertal gynecomastia. The diagnosis of AIS often proves to be a challenge; its management is complex and requires a multidisciplinary approach to meet decision-making challenges in sex assignment, fertility and timing of gonadectomy, psychological outcomes and genetic counselling.     

Metallic and Metal Oxides Nanoparticles for Sensing Food Pathogens—An Overview of Recent Findings and Future Prospects

Nowadays, special importance is given to quality control and food safety. Food quality currently creates significant problems for the industry and implicitly for consumers and society. The effects materialize in economic losses, alterations of the quality and organoleptic properties of the commercial products, and, last but not least, they constitute risk factors for the consumer’s health. In this context, the development of analytical systems for the rapid determination of the sanitary quality of food products by detecting possible pathogenic microorganisms (such as Escherichia coli or Salmonella due to the important digestive disorders that they can cause in many consumers) is of major importance. Using efficient and environmentally friendly detection systems for identification of various pathogens that modify food matrices and turn them into food waste faster will also improve agri-food quality throughout the food chain. This paper reviews the use of metal nanoparticles used to obtain bio nanosensors for the purpose mentioned above. Metallic nanoparticles (Au, Ag, etc.) and their oxides can be synthesized by several methods, such as chemical, physical, physico-chemical, and biological, each bringing advantages and disadvantages in their use for developing nanosensors. In the “green chemistry” approach, a particular importance is given to the metal nanoparticles obtained by phytosynthesis. This method can lead to the development of good quality nanoparticles, at the same time being able to use secondary metabolites from vegetal wastes, as such providing a circular economy character. Considering these aspects, the use of phytosynthesized nanoparticles in other biosensing applications is also presented as a glimpse of their potential, which should be further explored.     

Perinatal asphyxia in infants of insulin-dependent diabetic mothers

Infants of diabetic mothers are thought to be at risk for perinatal asphyxia. We hypothesized that the following are significant risk factors for perinatal asphyxia: poor third-trimester glycemic control, diabetic vascular disease (nephropathy, retinopathy) appearing in pregnancy, pregnancy-associated hypertension, smoking, prematurity, fetal macrosomia, and maternal hyperglycemia and hypoglycemia within 6 hours preceding delivery. We prospectively studied 162 infants born to 149 diabetic mothers (White classes B through R-T). Perinatal asphyxia was defined clinically as fetal distress during labor (late decelerations, persistent fetal bradycardia, or both), 1-minute Apgar score less than or equal to 6, or intrauterine fetal death. Forty-four infants (26.7%) had perinatal asphyxia. The presence of perinatal asphyxia did not correlate with third-trimester glycemic control, pregnancy-associated hypertension, smoking, fetal macrosomia, or maternal hypoglycemia before delivery, but it did correlate significantly with nephropathy appearing in pregnancy, maternal hyperglycemia before delivery, and prematurity. We speculate that (1) the appearance of diabetic vasculopathy (nephropathy) during pregnancy is accompanied by placental vascular disease and subsequently by fetal compromise and (2) in pregnancy complicated by diabetes, maternal and subsequently fetal hyperglycemia before delivery leads to fetal hypoxemia.