A novel mutant allele of Schizosaccharomyces pombe rad26 defective in monitoring S-phase progression to prevent premature mitosis

A semipermissive growth condition was defined for a Schizosaccharomyces pombe strain carrying a thermosensitive allele of DNA polymerase delta (pol delta ts03). Under this condition, DNA polymerase delta is semidisabled and causes a delay in S-phase progression. Using a genetic strategy, we have isolated a panel of mutants that enter premature mitosis when DNA replication is incomplete but which are not defective for arrest in G2/M following DNA damage. We characterized the aya14 mutant, which enters premature mitosis when S phase is arrested by genetic or chemical means. However, this mutant is sensitive to neither UV nor gamma irradiation. Two genomic clones, rad26+ and cds1+, were found to suppress the hydroxyurea sensitivity of the aya14 mutant. Genetic analysis indicates that aya14 is a novel allele of the cell cycle checkpoint gene rad26+, which we have named rad26.a14. cds1+ is a suppressor which suppresses the S-phase feedback control defect of rad26.a14 when S phase is inhibited by either hydroxyurea or cdc22, but it does not suppress the defect when S phase is arrested by a mutant DNA polymerase. Analyses of rad26.a14 in a variety of cdc mutant backgrounds indicate that strains containing rad26.a14 bypass S-phase arrest but not G1 or late S/G2 arrest. A model of how Rad26 monitors S-phase progression to maintain the dependency of cell cycle events and coordinates with other rad/hus checkpoint gene products in responding to radiation damage is proposed.     

The effect of various levels of chitosan in rat diet on vitamins assimilation under their combined deficiency

he effect of chitosan inclusion in the semi-synthetic diet of rats at a dose of 0,24 and 0,9% of dry weight on vitamin assimilation under combined moderate and deep deficiency has been studied. Four-week introduction of chitosan did not have a significant effect on levels of vitamins C, B1, B2 and A in the liver of animals, on vitamin B2 blood plasma concentration and thiamine and riboflavin urinary excretion regardless of the degree of vitamin deficiency intensity. The significantly decrease of vitamin E blood plasma concentration has been observed at high dose of chitosan in the diet under moderate vitamin deficiency, whereas under deep deficit such reduction has been detected even at a low dose. Thus, long-term chitosan inclusion in the diet under existing polyhypovitaminosis can lead to the deterioration of the sufficiency with fat-soluble vitamins.     

Ultrapurification of <Superscript>76</Superscript>Ge-enriched GeH<Subscript>4</Subscript> by distillation

⁷⁶Ge-enriched germane has been ultrapurified by low-temperature distillation. The nature and concentration of molecular impurities in the germane samples were determined by gas chromatography/mass spectrometry, high-resolution Fourier transform IR spectroscopy, and gas chromatography. The distillate contains no more than 10⁻⁵ mol % hydrocarbons, 10⁻⁴ mol % carbon dioxide, 10⁻³ to 10⁻¹ mol % digermane and trigermane, and <3 × 10⁻⁵ mol % other impurities. A distinctive feature of the impurity composition of the isotopically enriched germane samples is the presence of silicon tetrafluoride and sulfur hexafluoride impurities.     

Synthesis of compositionally different multicomponent metal-oxide films (SnO2) x (ZnO)1 − x (x = 1–0.5)

The study is concerned with high-purity SnO₂ and ZnO powders produced from salt solutions of corresponding metals by low-temperature hydrothermal synthesis. Fragments of SnO₂ and ZnO ceramic targets formed as 1 × 8 cm bars are fabricated by dry pressing. The bars are used to form composite targets for ion-beam sputtering and the fabrication of compositionally different (SnO₂) _x (ZnO)_{1 ? x} (x = 1–0.5) films appropriate for the production of gas sensors or transparent electronic devices. The optical and electrical parameters of the films with different compositions are studied.     

What are the sciences of relationship-centered primary care

Steroidogenic acute regulatory protein (StAR), a 30-kDa protein involved in the transport of cholesterol to inner mitochondrial membrane during stimulation of steroid hormone biosynthesis, has recently been cloned from human adrenals and MA-10 mouse Leydig tumor cells. We examined the regulation of StAR mRNA accumulation upon induction of steroidogenesis in immortalized rat granulosa cells. Granulosa cells were transfected with SV40 DNA alone (POGS5); with SV40 DNA and Ha-ras oncogene (POGRS1); with SV40 DNA, Ha-ras oncogene and LH/CG receptor (GLHR15) or with FSH receptor (GFSHR17) or with the beta 2-adrenergic receptor (G beta 2AR13) expression plasmids. Cells were cultured to confluency and then stimulated for 24 h with oFSH (4 nM), hCG (2.4 nM), isoproterenol (10 microM) or forskolin (50 microM). By quantitative RT-PCR, StAR mRNA was undetectable in non-steroidogenic cells (transfected with SV40 DNA alone, POGS5) either in the presence or in the absence of forskolin. In contrast, variable amount of the message was detected in all steroidogenic cell lines cotransfected with SV40 DNA and Ha-ras. Moreover, an increase in the StAR mRNA expression was evident in all steroidogenic cells upon stimulation with their respective agonists, concomitantly with enhanced progesterone production. The RT-PCR product was sequenced and the 379 base pairs of rat StAR were found to be 93% and 86% identical to mouse and human cDNA, respectively. The deduced 126 amino acid sequence was 95%, 88% and 88% identical to the mouse, human and bovine deduced protein sequences. We conclude that StAR message is expressed only in the steroidogenic rat granulosa cells and can be upregulated by FSH, hCG, isoproterenol and forskolin in the appropriate cell lines. In addition, we find that the rat StAR cDNA exhibit a high degree of homology with the mouse and human sequences.     

Oxidative stress: an important phenomenon with pathogenetic significance in the progression of acute pancreatitis

BACKGROUND: Reactive oxygen species and related oxidative damage have been implicated in the initiation of acute pancreatitis. Changes in these parameters during disease progression merit further investigation. AIMS: To evaluate changes and the clinical relevance of superoxide radicals, endogenous antioxidants, and lipid peroxidation during the course of acute pancreatitis. PATIENTS AND METHODS: Superoxide radicals (measured as lucigenin amplified chemiluminescence), ascorbic acid, dehydroascorbic acid, alpha tocopherol, and lipid peroxidation (measured as thiobarbiturate reactive substances) were analysed in blood samples from 56 healthy subjects, 30 patients with mild acute pancreatitis, and 23 patients with severe acute pancreatitis. The association with grades of disease severity was analysed. Measurements were repeated one and two weeks after onset of pancreatitis. RESULTS: In the blood from patients with acute pancreatitis, there were increased levels of the superoxide radical as well as lipid peroxides. There was notable depletion of ascorbic acid and an increased fraction of dehydroascorbic acid. Changes in alpha tocopherol were not great except in one case with poor prognosis. Differences between severe and mild acute pancreatitis were significant (p < 0.01). Variable but significant correlations with disease severity scores were found for most of these markers. The normalisation of these indexes postdated clinical recovery one or two weeks after onset of disease. CONCLUSIONS: Heightened oxidative stress appears early in the course of acute pancreatitis and lasts longer than the clinical manifestations. The dependence of disease severity on the imbalance between oxidants and natural defences suggests that oxidative stress may have a pivotal role in the progression of pancreatitis and may provide a target for treatment.     

A comparison of the investment in hospital-based obstetrical ultrasound in Wales and Washington state

The purpose of this study was to examine differences in the way Britain and the United States invest in and deploy a new medical technology. We used structured interviews to obtain information on the technical sophistication and approximate replacement value of all hospital-based obstetrical ultrasound machines in every maternity hospital in Washington state and Wales. The supply of hospital-based ultrasound machines--approximately two machines per 1,000 births--was similar in both countries. Wales had fewer advanced ultrasound machines than Washington state, and they were based exclusively in high-volume district general hospitals; there were no obstetric ultrasound machines in the private sector. In Washington state, the majority of advanced machines were in small and medium-sized hospitals, and many private offices had ultrasound machines. The approximate replacement value of hospital-based machines was three times as high per birth in Washington state as in Wales. In the case of obstetrical ultrasound, centralization of facilities, a relatively small private sector, and global budgeting lead to lower expenditures per patient within the National Health Service without compromising access to care.     

Molecular genetics of familial hypercholesterolemia in Israel

Recreational SCUBA diving exposes individuals to environmental stresses not often encountered in other types of activity. These stresses include increased ambient pressure, raised partial pressure of O(2), increased resistance to movement, added weight and drag of diving equipment, cold stress, and a higher breathing resistance. One means to understand how such stresses affect a diver is to employ the stress-strain-adaptive response model. Physiologic adaptations, like an increase in VO(2) in response to cold stress, will minimize the strain placed on thermal balance. Nonphysiologic adaptive responses include those behavioral and equipment interventions that isolate the diver from a particular stress. Self-contained underwater breathing apparatus (SCUBA) isolates the diver from the inability to extract O(2) from the water; dive garments minimize the stress of cold water immersion. This review will focus on cardiorespiratory and thermal responses to SCUBA diving, using the stress-strain-adaptive response model to illustrate the interaction between diver and environment. Some responses like hyperventilation, cardiac arrhythmias, or cold injury due to vasoconstriction are not considered adaptive but are realistic possibilities in diving environments.     

Experimental telemedicine in orthopaedics

An accurate technique that simplifies measurements of two- and three-dimensional specimens is presented. Photomicrographs of a microruler and of the specimens of a research project were made at the same magnification. A ruler with the exact dimensions of the photographic prints of the microruler was generated through computer graphics and printed as a transparency. After verification, the ruler was used to measure specimens directly on the photomicrographs.