Two-point calibration procedure of the forced oscillation technique

The extent of xre gene divergence was studied in nine soil bacillus strains with different degrees of relationship to Bacillus subtilis 168. This gene product is a repressor of defective phages. Bac. subtilis 168 recipient strains were transformed by DNA from these bacillus strains for the xhi-1479 marker and ten markers of amino acid and nitrous bases metabolism. The efficiency of soil strain DNA hybridization with Bac. subtilis 168 DNA was assessed. Eight strains were close to Bac. subtilis 168 with respect to the efficiency of heterotransformation for all markers and hybridization, and one strain (1621) strongly differed from other strains with regard to these parameters. As determined by the degree of differences in heterotransformation for all markers, the nucleotide sequence of the xre gene diverged in the evolution process at a rate similar to that of the nucleotide sequences of the housekeeping genes. All examined genes were shown to have similar selective value.     

Secondary intraocular lens implantation after cataract surgery in children

PURPOSE: To report results of secondary intraocular lens implantation after cataract surgery in children. METHODS: We reviewed clinical records for a 5-year period of patients who had cataract surgery in childhood and received a secondary intraocular lens implant. We studied indications for secondary intraocular lens placement; surgical procedures for intraocular lens implantation; preoperative and postoperative visual acuity, refractive error, and binocular status; and complications of the procedure. RESULTS: A secondary intraocular lens was placed in 28 eyes of 25 patients who had cataract surgery in childhood. In 20 eyes, the lenses were placed in the ciliary sulcus. The other eight eyes had insufficient capsular support for an intraocular lens; in two, the intraocular lens was placed in the anterior chamber and, in six, in the posterior chamber with suture fixation to the sclera. Twenty of 28 eyes (71%) had measurable improvement in visual acuity; only one eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye; 21 (75%) were within 3.00 diopters. During follow-up, two eyes developed glaucoma. One had transient pressure elevation; one required two filtration procedures. Three patients required Nd:YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near; three demonstrated 200 seconds of arc or better stereo visual acuity. CONCLUSION: Secondary placement of an intraocular lens in the posterior chamber appears to be a safe, effective alternative for correction of aphakia in the contact lens- or spectacles-intolerant child or young adult.     

Localization of bacterial DNA polymerase: evidence for a factory model of replication

Two general models have been proposed for DNA replication. In one model, DNA polymerase moves along the DNA (like a train on a track); in the other model, the polymerase is stationary (like a factory), and DNA is pulled through. To distinguish between these models, we visualized DNA polymerase of the bacterium Bacillus subtilis in living cells by the creation of a fusion protein containing the catalytic subunit (PolC) and green fluorescent protein (GFP). PolC-GFP was localized at discrete intracellular positions, predominantly at or near midcell, rather than being distributed randomly. These results suggest that the polymerase is anchored in place and thus support the model in which the DNA template moves through the polymerase.     

Determinants of risk for cardiovascular disease during school-age/adolescent transition

During the past two decades, emphasis has been placed on exploring the development of cardiovascular disease (CVD) during childhood. Hypercholesterolemia, the most prevalent of the CVD risk factors among children, has been the focus of some large population-based studies. These studies tend to relate only to the physiological aspect of the school-age/adolescent transitional phase and do not necessarily address the collective contributions of the early adolescent experience, including psychosocial and cognitive factors. Thus, minimal information exists on the determinants of the CVD risk factor during this time of growth and rapid developmental change. Relatively unexplored are the interrelationships among the determinants of hypercholesterolemia (and CVD) observed in studies of adults, including sociodemographic, biodevelopmental and behavioral factors. Since the adolescent transition is a critical period for the formation of health-promoting behaviors, knowledge of these interrelationships is requisite to developing specific and timely preventive interventions. An adaptation of the Health Promotion Model is used to guide the exploration of the knowledge to date regarding the sociodemographic, biodevelopmental and behavioral factors in the school-age/adolescent population.     

Molecular structure and antioxidant specificity of purpurogallin in three types of human cardiovascular cells

Purpurogallin (PPG) in an active cytoprotector found in certain oak barks. We have shown that PPG prolongs the survival of cultured cardiocytes from rats and rabbits against different oxidants better than do antioxidants such as Trolox (a hydrophilic analogue of vitamin E) in a morphometric assay system. First, we verified by X-ray crystallography that PPG is a bicyclic molecule comprising a phenolic ring fused with a seven-membered ring in a highly planar conformation. In analogues of PPG wherein the two double bonds in the seven membered ring of the parent molecule are saturated or where the four OH groups of the parent compound are substituted by four OCH3 groups, the derivatives are less planar and less protective of the human cells than native PPG. Second, PPG in a concentration-dependent manner protected myocytes and endothelial cells of humans against oxyradicals generated with any one of the following oxyradical generators: (a) xanthine oxidase plus hypoxanthine, (b) menadione, or (c) paraquat. In each case, PPG was more cytoprotective than comparative antioxidants. Also, PPG protected erythrocytes against peroxyl radicals better than the two PPG derivatives mentioned. Third, the cytoprotective action of PPG detected in vitro was accompanied by declines of malondialdehyde. Finally, we observed that PPG chelated ferrous ions and, therefore, can suppress the formation of radicals in the Fenton reaction. Thus, PPG with its molecular architecture and presumably its affinity for ferrous ions protects multiple types of cardiovascular cells against oxyradicals.     

Changes in the physiological functions, the mechanisms of their recovery and the temperature limits for life under hypothermia

On the basis of the newest literature and author's own investigations the variations of the main life ensuring functions (the minute volume of respiration, the oxygen transport functions of the blood, the tissue oxygen supply ect) are analyzed under the immersion hypothermia in homoisothermal animals and man. The mechanisms of these function variations under hypothermia of various degree are described. On the basis of the newest theories of cold action on a cell the main physiological mechanisms of oppressing these functions are described, which result in the loss of homoiothermy. The possibilities and regularities of the physiological function resuscitation after deep hypothermia are analyzed. The factors, influencing the level of the lower temperature limit of life in homoiothermal animals, are determined.     

An investigation of the intra-generic structure of Rothia by pyrolysis mass spectrometry

Some women with benign breast disease eventually develop breast cancer. The mammary gland undergoes tissue remodelling according to hormonal influences, involving a balance between quiescence, proliferation, and mechanisms of cell death. Proliferation and/or apoptotic events could therefore be investigated to help understand the mechanisms of benign lesion formation and identify mastopathies with a poor prognosis. bcl-2 expression was analysed by immunohistochemistry in 75 benign mastopathies. Protein levels were quantitated with an image analyser in various epithelial structures on frozen sections, including adenoses, fibroadenomas, ductal epithelial hyperplasias, cysts, and apparently normal surrounding lobules and ducts. bcl-2 levels were equivalent in apparently normal lobules and ducts, as well as in cysts and ductal hyperplasias. bcl-2 staining was significantly higher in fibroadenomas, known to be of lobular origin [mean = 10.1, quantitative immunochemistry score (QIC) arbitrary units (AU), n = 19], than in normal lobules (mean = 5.1 AU, n = 43, P = 7 x 10(-5). bcl-2 levels in normal lobules and ducts varied according to the menstrual cycle, being higher during the follicular than the luteal phase (P = 1.8 x 10(-2) and P = 1.7 x 10(-2), respectively). This was further supported by a statistical link (P = 5 x 10(-3) between high levels of circulating progesterone and weak bcl-2 staining in lobules and ducts. This progesterone-dependent variation was absent in fibroadenomas. No statistical correlation was found between bcl-2 expression and circulating levels of oestradiol, and follicle-stimulating or luteotrophic hormones. Although these are only preliminary results, they suggest an influence of progesterone on bcl-2 expression which might be lost in fibroadenomas. A hypothesis is proposed concerning the potential involvement of altered regulation of the apoptotic process in the formation of such benign lesions.