Modulation of embryonic NA+-K+-ATPase activity and mouse preimplantation development in vitro in media containing high concentrations of potassium

The effect of various potassium concentrations (ranging from 1.4 mM to 30 mM K⁺) in modified Tyrode's medium on the culture of mouse zygotes obtained after in vitro fertilization to the blastocyst stage was examined. A clear dose-dependent negative effect of increasing K⁺ concentrations on the preimplantation embryonic development in vitro was found. We have previously shown that significantly more two-cell embryos reach the blastocyst stage when cultured during the second day postinsemination in medium supplemented with taurine. Because taurine, an amino acid that abounds in the reproductive tract, has been reported to inhibit the enzyme Na⁺-K⁺-adenosine triphosphatase (Na⁺-K⁺-AT-Pase), we used two other conditions known to inhibit the Na⁺-K⁺-ATPase to study their effect on mouse embryo development. Culturing embryos during a short period (the second day postinsemination) in low extracellular K⁺ concentrations (1.4 mM) or in medium supplemented with ouabain (50 μM) showed positive effects similar to those of culturing in medium with taurine (10 mM). This beneficial effect of ouabain was found in various K⁺ concentrations tested, including the high concentrations present in the oviduct. Although the effects of low K⁺ and taurine can possibly be ascribed to their other cellular effects, the effect of ouabain shows that inhibition of the Na⁺-K⁺-ATPase during the two-cell stage in the mouse is beneficial for further embryonic development to the blastocyst stage. © 1993 Wiley-Liss, Inc.     

Parental origin of chromosome abnormalities in spontaneous abortions

Summary Tissue cultures were initiated from 130 spontaneous abortion specimens and 81 were successfully karyotyped. Chromosome abnormalities were found in 50 cases: 12 with XO, 27 with trisomy, 6 with triploidy, 1 with tetraploidy and 4 others. The parental origin was determined in 11 cases of trisomy for an acrocentric chromosome. Two cases were uninformative while 9 non-disjunctions were determined and occurred during meiosis I: 7 were maternal and 2 paternal (both with trisomy 21). Three out of 7 cases with trisomy 16 were informative and resulted from a divisional error during the first meiotic division in the mother. All cases of triploidy were informative. They resulted from non-reduction during meiosis I in the mother (2) or dispermy (4).     

Interaction of tryptophan-modified analogues of cholecystokinin-octapeptide with cholecystokinin receptors on pancreatic acini

None of six different tryptophan-modified analogues of the C-terminal octapeptide of cholecystokinin differed from the unaltered peptide in terms of their efficacies for stimulating amylase secretion from dispersed acini prepared from guinea-pig pancreas. Replacementof hydrogen with fluorine in position 5 or 6 on the indole ring of the tryptophan residue did not alter the potency with which the peptide stimulated amylase secretion; however, replacement of hydrogen by fluorine in positions 4, 5, 6, and 7 of the indole ring, of modifying or replacing the indole nitrogen caused a 30- to 300-fold decrease in potency. Changes in the ability of the peptide to stimulate amylase secretion were accompanied by corresponding changes in the ability of the peptide to inhibit binding of ¹²⁵I-labeled cholecystokinin. Our findings indicate that reducing the ability of the tryptophan residue to donate electrons produced a greater decrease in the affinity of the peptide for the cholecystokinin receptors than did abolishing the ability of tryptophan to form hydrogen bonds, and modifications that altered both abilities caused a greater decrease in affinity than did modification of only one ability. Finally, in the tryptophan residues of cholecystokinin octapeptide, tetrafluorination of the indole ring or replacing the indole nitrogen by oxygen reduced the ability of the peptide to cause residual stimulation of enzyme secretion, probably by accelerating the rate at which bound peptide dissociated from its receptors when the acini were washed and resuspended in fresh incubation solution.     

A Living Biobank of Breast Cancer Organoids Captures Disease Heterogeneity

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The recognition of abnormal sex chromosome constitution by HLA-restricted anti-H-Y cytotoxic T cells and antibody

Using the cell-mediated lympholysis (CML) technique, we studied lymphocytes of six individuals with discrepancies between the karyotypic and phenotypic sex. Two sets of cytotoxic T cells (CTLs) obtained from two multitransfused female aplastic anemia patients were used as typing reagents. These cells were previously shown to kill allogeneic target cells from HLA-A2- or B7-positive male donors. An antiserum obtained from one of the patients likewise killed HLA-A2 male lymphocytes. The six patients studied were selected for the required antigens. Positive reactions were obtained with lymphocytes from a 46, XY woman with pure gonadal dysgenesis and a 45, XO male. Target cells of the mother of the latter patient were also lysed. One individual with a 45, XO/46, X, del(Y)? karyotype was weakly positive, while three 46, XX males were completely negative. The reactivity of the HLA-A2-restricted H-Y-specific antibody showed the same discriminatory patterns. The results obtained by theHLA-restricted CTLs as well as by the antiserum did not correlate with the presence of testes as is the case in a different test system for the serologically detectable male (SDM) antigen in man. On the other hand, there was a correlation with the presence of cytologically detectable Y-chromosome material in five of the six individuals studied. The HLA-restricted CTLs and the antibody might recognize the classical transplantation antigen H-Y.     

Identification of Enteroendocrine Regulators by Real-Time Single-Cell Differentiation Mapping

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The functional costs and benefits of dietary restriction in Drosophila

Dietary restriction (DR) extends lifespan in an impressively wide array of species spanning three eukaryotic kingdoms. In sharp contrast, relatively little is known about the effects of DR on functional senescence, with most of the work having been done on mice and rats. Here we used Drosophila melanogaster to test the assumption that lifespan extension through DR slows down age-related functional deterioration. Adult virgin females were kept on one of three diets, with sucrose and yeast concentrations ranging from 7% to 11% to 16% (w/v). Besides age-specific survival and fecundity, we measured starvation resistance, oxidative stress resistance, immunity, and cold-stress resilience at ages 1, 3, 5, and 7 weeks. We confirmed that DR extends lifespan: median lifespans ranged from 38 days (16% diet) to 46 days (11% diet) to 54 days (7% diet). We also confirmed that DR reduces fecundity, although the shortest-lived flies only had the highest fecundity when males were infrequently available. The most striking result was that DR initially increased starvation resistance, but strongly decreased starvation resistance later in life. Generally, the effects of DR varied across traits and were age dependent. We conclude that DR does not universally slow down functional deterioration in Drosophila. The effects of DR on physiological function might not be as evolutionarily conserved as its effect on lifespan. Given the age-specific effects of DR on functional state, imposing DR late in life might not provide the same functional benefits as when applied at early ages.     

Low Rates of Both Lipid-Lowering Therapy Use and Achievement of Low-Density Lipoprotein Cholesterol Targets in Individuals at High-Risk for Cardiovascular Disease across Europe

AimsTo analyse the treatment and control of dyslipidaemia in patients at high and very high cardiovascular risk being treated for the primary prevention of cardiovascular disease (CVD) in Europe.ConclusionsThere is a considerable opportunity for improvement in rates of lipid-lowering therapy use and achievement of lipid-level targets in high-risk and very-high-risk patients being treated for primary CVD prevention in Europe.     

Outcomes and Diagnostic Processes in Outpatients with Presumptive Tuberculosis in Zomba District,Malawi

Background

In Malawi, outpatients who have presumptive tuberculosis (TB), i.e. fever, night sweats, weight loss and/or any-duration cough (HIV-infected) or cough of at least 2 weeks (HIV-uninfected), are registered in chronic cough registers. They should receive a diagnostic work-up with first-step provider-initiated HIV testing and sputum testing which includes XpertMTB/RIF, following a national algorithm introduced in 2012.

Methods

An operational study, in which we prospectively studied 6-month outcomes of adult outpatients who were registered in chronic cough registers in Zomba Central Hospital and Matawale peri-urban Health Center, between February and September 2013. We recorded implementation of the diagnostic protocol and outcomes at 6 months from registration.

Results

Of 348 patients enrolled, 165(47%) were male, median age was 40 years, 72(21%) had previous TB. At registration 154(44%) were known HIV-positive, 34(10%) HIV-negative (26 unconfirmed) and 160(46%) had unknown HIV status; 104(56%) patients with unknown/unconfirmed HIV status underwent HIV testing. At 6 months 191(55%) were HIV-positive, 87(25%) HIV-negative (26 unconfirmed) and 70(20%) still had unknown HIV status. Higher age and registration in Matawale were independently associated with remaining unknown HIV status after 6 months. 62% of patients had sputum tested, including XpertMTB/RIF, according to the algorithm. TB was diagnosed in 54(15%) patients. This was based on XpertMTB/RIF results in 8(15%) diagnosed cases. In 26(48%) TB was diagnosed on clinical grounds. Coverage of ART in HIV-positive patients was 89%. At 6 months, 236(68%) were asymptomatic, 48(14%) symptomatic, 25(7%) had been lost-to-follow-up and 39(11%) had died. Mortality among those HIV-positive, HIV-negative and with unknown HIV-status was 15%, 2% and 10%, respectively. Male gender, being HIV-positive-not-on-ART and not receiving antibiotics were independent risk factors for mortality.

Conclusion

HIV prevalence among patients with presumptive TB was high (55%). One quarter was not HIV tested and mortality in this group was substantial (10%). The impact of XpertMTB/RIF on TB diagnosis was limited.