Seminiferous tubule transfection in vitro to define post-meiotic gene regulation

Background  

Post-meiotically expressed genes in the testis are essential for the proper progression of spermatogenesis, and yet, aside from the construction of individual transgenic mice using specific promoters to drive reporter plasmids, there are only very limited possibilities for relevant and quantitative analysis of gene promoters. This is due to the special nature of post-meiotic haploid cells, which to date are not represented in any appropriate cell-lines. This article reports the development of novel methodology using isolated and cultured rat seminiferous tubules in a multiwell format, into which promoter-reporter constructs can be introduced by a combination of microinjection and electroporation.     

Declining incidence of AIDS dementia complex after introduction of zidovudine treatment.

OBJECTIVE--To assess the incidence of the AIDS dementia complex and the presence of HIV I p24 antigen in cerebrospinal fluid in relation to zidovudine treatment. DESIGN--Retrospective study of a consecutive series of patients with AIDS from 1982 to 1988. SETTING--An academic centre for AIDS. PATIENTS--196 Patients with AIDS and neurological symptoms examined from 1982 to 1988. INTERVENTIONS--Zidovudine treatment, which was introduced to The Netherlands on 1 May 1987 for patients with severe symptoms of HIV infection (Centers for Disease Control groups IVA, B, C, and D). MAIN OUTCOME MEASURES--Diagnosis of AIDS dementia complex and presence of HIV I p24 antigen in cerebrospinal fluid. RESULTS--The AIDS dementia complex was diagnosed in 40 of the 196 (20%) patients with AIDS. Thirty eight of 107 patients with AIDS (36%) not taking zidovudine developed the AIDS dementia complex compared with two of the 89 (2%) taking the drug (p less than 0.00001). The incidence of the AIDS dementia complex increased to 53% in the first half of 1987, after the introduction of zidovudine in May 1987, decreasing to 10% in the second half of 1987 and to 3% in 1988. Dementia was diagnosed before definition of the AIDS dementia complex (1986) according to DSM-III criteria and there was good agreement between diagnosis before and after 1986. Sixteen of 61 samples of cerebrospinal fluid (26%) from patients with AIDS (10 with the AIDS dementia complex) not taking zidovudine were positive for HIV I p24 antigen, whereas none of 37 cerebrospinal fluid samples from patients with AIDS (two with the AIDS dementia complex) taking zidovudine were positive. CONCLUSIONS--The incidence of AIDS dementia complex in patients with AIDS declined after the introduction of systematic treatment with zidovudine; the AIDS dementia complex might be prevented by inhibiting viral replication in the central nervous system.     

Population genetics and phylogenetics of DNA sequence variation at multiple loci within the Drosophila melanogaster species complex

Two regions of the genome, a 1-kbp portion of the zeste locus and a 1.1- kbp portion of the yolk protein 2 locus, were sequenced in six individuals from each of four species: Drosophila melanogaster, D. simulans, D. mauritiana, and D. sechellia. The species and strains were the same as those of a previous study of a 1.9-kbp region of the period locus. No evidence was found for recent balancing or directional selection or for the accumulation of selected differences between species. Yolk protein 2 has a high level of amino acid replacement variation and a low level of synonymous variation, while zeste has the opposite pattern. This contrast is consistent with information on gene function and patterns of codon bias. Polymorphism levels are consistent with a ranking of effective population sizes, from low to high, in the following order: D. sechellia, D. melanogaster, D.mauritiana, and D. simulans. The apparent species relationships are very similar to those suggested by the period locus study. In particular, D. simulans appears to be a large population that is still segregating variation that arose before the separation of D. mauritiana and D. sechellia. It is estimated that the separation of ancestral D. melanogaster from the other species occurred 2.5-3.4 Mya. The separations of D. sechellia and D. mauritiana from ancestral D. simulans appear to have occurred 0.58- 0.86 Mya, with D. mauritiana having diverged from ancestral D. simulans 0.1 Myr more recently than D. sechellia.      

Oxide-Based Solid-State Batteries: A Perspective on Composite Cathode Architecture

The garnet-type phase Li₇La₃Zr₂O₁₂ (LLZO) attracts significant attention as an oxide solid electrolyte to enable safe and robust solid-state batteries (SSBs) with potentially high energy density. However, while significant progress has been made in demonstrating compatibility with Li metal, integrating LLZO into composite cathodes remains a challenge. The current perspective focuses on the critical issues that need to be addressed to achieve the ultimate goal of an all-solid-state LLZO-based battery that delivers safety, durability, and pack-level performance characteristics that are unobtainable with state-of-the-art Li-ion batteries. This perspective complements existing reviews of solid/solid interfaces with more emphasis on understanding numerous homo- and heteroionic interfaces in a pure oxide-based SSB and the various phenomena that accompany the evolution of the chemical, electrochemical, structural, morphological, and mechanical properties of those interfaces during processing and operation. Finally, the insights gained from a comprehensive literature survey of LLZO–cathode interfaces are used to guide efforts for the development of LLZO-based SSBs.     

rG-CSF reduces endotoxemia and improves survival during E.coli pneumonia

Freeman, Bradley D., Zenaide Quezado, Fabrice Zeni, CharlesNatanson, Robert L. Danner, Steven Banks, Marcello Quezado, YvonneFitz, John Bacher, and Peter Q. Eichacker. rG-CSF reduces endotoxemia and improves survival during E. coli pneumonia. J. Appl.Physiol. 83(5): 1467-1475, 1997.We investigatedthe effects of recombinant granulocyte colony-stimulating factor(rG-CSF) during canine bacterial pneumonia. Beagles with chronictracheostomies received daily subcutaneous rG-CSF (5 µg/kg body wt)or placebo for 14 days, beginning 9 days before intrabronchialinoculation with E. coli. Animalsreceived antibiotics and fluid support; a subset received humidifiedoxygen (fractional inspired O₂0.40). Compared with controls, rG-CSF increased circulating neutrophil counts (57.4 vs. 11.0 × 10³/mm³,day 1 after infection;P = 0.0001), decreased plasmaendotoxin (7.5 vs. 1.1 EU/ml at 8 h; P < 0.01) and serum tumor necrosis factor- (3,402 vs.729 pg/ml at 2 h; P = 0.01) levels,and prolonged survival (relative risk of death = 0.45, 95% confidenceinterval 0.21-0.97; P = 0.038).Also, rG-CSF attenuated sepsis-associated myocardial dysfunction(P < 0.001). rG-CSF had no effect onpulmonary function or on blood and lung bacteria counts (allP = not significant). Other animalschallenged with endotoxin (4 mg/kg iv) after similar treatment withrG-CSF had lower serum endotoxin levels (7.62 vs. 5.81 log EU/ml at 6 h; P < 0.01) and less cardiovasculardysfunction (P < 0.05 to < 0.002)but similar tumor necrosis factor- levels (P = not significant) compared withcontrols. Thus prophylactic rG-CSF sufficient to increase circulatingneutrophils during bacterial pneumonia may improve cardiovascularfunction and survival by mechanisms that in part enhance the clearanceof bacterial toxins but do not improve lung function.

     

Interaction of glutathione analogues with Hydra attenuata gamma-glutamyltransferase.

gamma-Glutamyltransferase activity was studied in extracts of the cnidarian Hydra attenuata. The binding of gamma-glutamyl peptide analogues to the enzyme was studied by observing their effects on heat denaturation and their inhibition of p-nitroaniline release from gamma-glutamyl p-nitroanilide. Neither position-1 analogues, in which the gamma-glutamyl moiety was changed to a beta-aspartyl (beta-Asp-Abu-Gly) or an alpha-glutamyl (Glu-Abu-Gly) linkage, nor glutamate protected the enzyme against inactivation at 58 degrees C. GSH (reduced glutathione), gamma-Glu-Abu-Gly and gamma-Glu-Met on the other hand did prevent heat denaturation. GSH and analogues of GSH were competitive inhibitors of p-nitroaniline release, but those analogues in which glycine was replaced by 2-aminoisobutyrate, phenylalanine, leucine or tyrosine had Ki values that were approximately five times those of analogues with the cysteine residue replaced.