cis-Elements in the 5''-region of the Oct-1 gene. Possibilities of autoregulation

The anti-diuretic hormone vasopressin (AVP) regulates water excretion from the kidney by increasing the water permeability of the collecting duct. AVP binds to V2-receptors and induces the translocation of aquaporin-2 water channels (AQP-2) into the apical plasma membrane of principal cells. By this mechanism AVP controls water reabsorption in the kidney. The effects of AVP on the endolymphatic sac (ES) of the inner ear, which is thought to mediate reabsorption of endolymph, were investigated. Both the V2-receptor and the AQP-2 water channel were found to be expressed in the ES epithelium. In the ES AVP binds to receptors most probably of the V2-subtype. Application of AVP to organotypically cultured ES inhibits membrane turnover in ribosomal-rich cells of the ES epithelia, which is thought to mediate translocation of AQP-2 into the surface membrane. This suggests that AVP has contrasting effects in the inner ear and kidney, which may be physiologically useful for maintaining endolymphatic pressure during severe hypovolemia. Animal experiments show that AVP causes endolymphatic hydrops after systemic application to guinea-pigs, which suggests a causal role for the increased AVP levels found in humans suffering from Ménière's disease.     

Doctors who perform operations. A study on in-hospital surgery in four diverse geographic areas (first of two parts)

The generous supply of surgeons in the United States stimulated a study of their operative work based on all operations performed by all physicians in hospitals of four geographic areas. Each operation was assigned a California Relative Value to permit work-load comparisons between specialties and practices. General practitioners constituted more than one quarter of physicians who performed operations but accounted for less than one tenth of total work. Surgical specialists, about half the physicians in the study, performed about 80 per cent of total operative work. Work loads of surgical specialists varied by certification, specialty, age and practice organization status. We conclude that far too many physicians perform surgical operations and that work loads of surgical specialists are modest. Calculations involving reallocation of operative work loads suggest that the total volume of operations in this study could have been handled by a substantially smaller cadre of busier surgical specialists.     

The development of allergy in infants of allergic parents: a prospective study concerning the role of heredity

Ninety-four infants of allergic mothers were studied from birth to age 24 months. If the father was also allergic, the family history was termed bilateral (36 infants); if the father was not allergic, the family history was termed unilateral (58 infants). Data concerning family history, methods of feeding (bottle versus breast) and allergic skin reactivity were obtained. Significantly, more infants developed allergy if they were from a bilateral allergic parentage (P = less than 0.044). When skin test negative, bottle-fed infants with a bilateral family history were compared to breast-fed infants with a unilateral family history, there was significantly less asthma in the latter group (P = less than 0.047). During the first three months of life there was significantly less atopic dermatitis in the breast-fed infants with an unilateral family history than in the breast-fed infants with a bilateral family history (P = less than 0.027). In this study it remained unclear why infants with positive allergy skin tests demonstrated a different incidence of allergic disease from those who were skin-test negative when the variables of family history were the same.     

Improving the reliability of determination of the compression modulus of silty-clayey soils from the results of compression tests

Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 21–22, March–April, 1990.     

Tumor necrosis factor-induced release of endogenous fatty acids analyzed by a highly sensitive high-performance liquid chromatography method

A highly sensitive method to determine agonist-induced release of endogenous fatty acids from cells in culture was developed using high-performance liquid chromatography and fluorescence detection. Fatty acids were selectively derivatized with 1-pyrenyldiazomethane and separated on a LC18 reversed phase column using an acetonitrile-water gradient. The detection limit was approx. 20 fmol and the recovery of the complete method using oleic acid was 93-98%. Tumor necrosis factor alpha (TNF-alpha) increased the extracellular release of endogenous arachidonic acid (20:4n-6) from 21 to 153 pmol/well per 4 h using 2.7 x 10(6) WEHI fibrosarcoma cells. In cells preincubated with 50 microM 20:4n-6, the corresponding figures were 463 and 3379 pmol 20:4n-6/well. Simultaneously, nearly equimolar amounts of 22:4n-6 were released together with slightly lower amounts of 24:4n-6, 16:0, 16:1n-9, and 18:1n-9. Analysis of cell lipid fatty acids showed that phosphatidylcholine was the major source of the released fatty acids. TNF-alpha increased the intracellular concentration of unesterified 20:4n-6 and 22:4n-6 by 368% and 451%, respectively. This suggests that released 20:4n-6 is rapidly chain elongated to 22:4n-6. The results indicate that the present method facilitates studies on agonist-induced release of endogenous fatty acids, and that TNF-induced fatty acid release seems to be less selective for 20:4n-6 than previously reported.