Urinary aquaporin-2 levels in healthy volunteers

SUMMARY:   Renal water handling is regulated by the release of arginine vasopressin (AVP) and the subsequent insertion of aquaporin 2 (AQP2) in the apical membrane of collecting duct cells. This in turn increases the membrane permeability to water and the passive reabsorption of water down the concentration gradient present in the medulla. Aquaporin 2 can be detected in the urine under conditions of antidiuresis. We wish to validate an assay for urinary AQP2. Fourteen volunteers participated in studies of water loading and water deprivation followed by the administration of 1-deamino-8- d -arginine vasopressin (dDAVP). Urine osmolality was measured by vapour pressure osmometry. Urinary AQP2 was measured by using a chemiluminescent assay. Baseline correlations between serum AVP levels, urinary osmolality and urinary AQP2 levels were not significant. Following the administration of dDAVP, a positive correlation between urine osmolality and urinary AQP2 was evident ( r  = 0.762). For specific conditions where renal water retention is stimulated via AVP, urinary AQP2 measurements provide a reproducible measurement of the renal actions of AVP.     

Expression of CD44 in uterine cervical squamous neoplasia: a predictor of microinvasion?

OBJECTIVE: CD44, an integral membrane glycoprotein, may have an important role in early tumorigenesis, specifically, facilitating early tumor progression. Reports of the expression of CD44 in early uterine cervical squamous carcinogenesis are conflicting. We examined the expression of CD44 in microinvasive carcinoma of the cervix (MIC), as yet unreported, and compared it to that in cervical intraepithelial neoplasia (CIN) 1 and CIN 3 to further elucidate its role in early squamous carcinogenesis. METHODS: Seventeen cases of CIN 1, 24 cases of CIN 3, and 20 cases of MIC were stained with antibodies to CD44s, CD44v5, and CD44v6. Only membranous staining was considered positive. RESULTS: Positive membranous staining (>50% cells) was observed in 97% of cases of CIN 1 using all three antibodies. In CIN 3, positive staining was seen more often with CD44v6 (18/24) and CD44v5 (19/24) than with CD44s (6/24). Expression of CD44v6 was retained more often in MIC (16/20) compared with CD44s (3/20) and CD44v5 (9/20). Those cases of CIN 3 and MIC that failed to meet our criteria for positive staining showed either heterogeneous or absent staining. CONCLUSION: There is a qualitative and quantitative reduction in expression of CD44 in MIC and CIN 3 compared with CIN 1. Down-regulation of CD44 variants may occur later in neoplastic progression than CD44s. This pattern may reflect their important biological function in early progression by cervical cancer cells. Patchy and heterogeneous staining in more advanced lesions limits the usefulness of CD44 and its variants in the assessment of microinvasion.     

Maternal stress and obstetric and infant outcomes: epidemiological findings and neuroendocrine mechanisms

This review examines the associations between antenatal maternal stress and obstetric and infant outcomes using preterm delivery as the key outcome indicator. This was done by means of a Medline search focusing predominantly on prospective, controlled studies which investigated both the associated epidemiological factors and putative neuroendocrine mechanisms. There is evidence from a number of United States studies in economically deprived African American women for an association between perceived maternal life event (LE) stress and preterm delivery. The findings from the European studies are conflicting, partly because they combine outcome measures ie. preterm delivery and low birth weight. However the three largest Scandinavian epidemiological studies examining preterm delivery and controlling for confounders such as smoking, age and obstetric history, have confirmed this association. These studies taken together suggest that this may be a robust finding not limited to socioeconomically deprived African American samples and independent of other significant risk factors. Two small prospective studies examining the relationship between the hypothalamic-pituitary-adrenal (HPA) axis, psychosocial status and premature delivery have reported a significant association between a set of adverse psychosocial factors on the one hand, and levels of adrenocorticotrophic hormone (ACTH), corticotrophin releasing hormone (CRH) and cortisol levels, and on the other hand, a significant correlation between CRH levels and premature delivery. Clearly, these findings remain preliminary and indicate a complex relationship between perceived stress in pregnancy, the HPA axis and premature delivery. The impact of antenatal maternal stress on infant temperament and psychopathology remains to be examined more fully in prospective controlled trials.     

Breastfeeding and childhood asthma: a six-year population-based cohort study

Background  

The question of the protective effect of breastfeeding on development of asthma has raised substantial interest, but the scientific evidence of the optimal duration of breastfeeding is controversial.     

Head insulation and heat loss in the newborn

The thermal balance of 13 term infants was measured in a closed-circuit metabolism chamber. Each was studied naked, then with a gamgee-lined hat, and finally with a 'cummerbund' made of a similar material and of similar dimensions. At 27 degrees C the oxygen consumption of the 'hatted' babies was only 85% and the total heat loss 75% of the values measured with the infants naked. The cummerbund offered no detectable benefit. An additional 10 infants were studied while wearing a tubegauze hat at environmental temperatures of 28.5 (+/- 0.5) degrees C. This type of hat gave no measurable thermal protection. It is concluded that a substantial reduction of thermal stress in adverse environments can be achieved simply and clearly by adequately covering the vault of the skull.     

Functional intestinal obstruction due to deficiency of argyrophil neurones in the myenteric plexus. Familial syndrome presenting with short small bowel, malrotation, and pyloric hypertrophy

In 3 infants functional intestinal obstruction, associated with a short small intestine, malrotation, and pyloric hypertrophy, was shown to be due to failure of development of the argyrophil myenteric plexus, with the absence of ongoing peristalsis. 4 infants with similar clinical features have been described previously, and there is evidence for an autosomal recessive mode of inheritance of this syndrome.     

Pet sensitivities in asthmatic children

A history of pet contact and/or apparent clinical sensitivity was obtained in 65 (55%) of 118 unselected asthmatic children. These 65 children were skin tested and their sera examined for specific IgE using the radioallergosorbent test. Those children who had apparent clinical sensitivities had larger skin test reactions and were more likely to have positive specific IgE results than those without apparent sensitivities. Positive skin tests were very common (80%), but the larger the skin test reaction (weal diameter greater than 4 mm diameter) the more likely was there to be a positive history or a positive specific IgE result. Hence a large skin test reaction can provide a helpful pointer to animal allergy of clinical importance. Commercially available animal extracts have limitations for diagnostic tests. A questionnaire survey of 150 day schools emphasized the potential opportunities for contact with animal allergens at school.