Effect of continuous infusion of a low dose of GnRH antagonist on serum LH and testosterone concentrations, spermatogenesis and semen quality in the rhesus monkey (Macaca mulatta)

Treatment of 4 adult male rhesus monkeys for 8-12 months with 100-400 micrograms of a GnRH antagonist/day by means of using osmotic minipumps led to suppressed serum concentrations of LH and testosterone followed by various degrees of recovery toward pretreatment values. The serum LH response to a challenge of native GnRH was reduced by 30-75% during antagonist treatment. The serum testosterone response to GnRH was exaggerated above the response in the pretreatment period, suggesting hypersensitivity of the testis to gonadotrophin. Antagonist administration under these conditions did not alter body weight or abolish ejaculatory response. Antagonist infusion caused a 96% decrease in sperm counts. Spermatozoa recovered during the final month of antagonist treatment showed a reduced ability to penetrate denuded hamster ova. Testicular biopsies performed at the end of antagonist treatment revealed persistent spermatogenesis. However, the cellularity of the seminiferous tubules was decreased below that of pretreatment biopsies. The results of this study suggest that the amount of testosterone needed to maintain normal spermatogenesis is greater than that needed to maintain electroejaculatory response in monkeys.     

Membrane penetration of bovine factor V and Va detected by labeling with 5-iodonaphthalene-1-azide

The membrane-binding properties of Factor V and Factor Va were investigated using the lipophyllic, photoactivable probe 5-[125I]iodonaphthalene-1-azide. In the presence of vesicles composed of 75% phosphatidylcholine and 25% phosphatidylserine, both Factor V and Va were found to be labeled by the probe. The label was almost exclusively localized to the carboxyl-terminal-derived component E of Factor Va. The results are consistent with the interpretation that component E is the membrane binding subunit of Factor Va and that the interaction between Factor V or Factor Va and the membrane involves the penetration of the protein into the lipid bilayer.     

Cytotoxic T lymphocytes from mice with soluble class I Q10 molecules in their serum are not tolerant to membrane-bound Q10

Q10 is a class I Qa-2 region-encoded molecule that is secreted by the liver and present in serum at high concentrations (about 10 to 60 micrograms/ml) in most strains of mice. The amino terminal portion of this molecule can also be expressed as an integral membrane protein by splicing the 5' end of the Q10 gene to the 3' end of H-2Ld and transfecting the hybrid gene into murine L cells. Because CTL primarily recognize polymorphic determinants controlled by the alpha 1 and alpha 2 domains of class I molecules and because the Q10d/Ld product expressed by transfected L cells includes the alpha 1 and alpha 2 domains of Q10d, we could address whether mice bearing serum Q10 were tolerant to this molecule at the CTL level. The results of these experiments demonstrate that Q10+ mice are able to generate H-2-unrestricted CTL activity against Q10d expressed on transfected L cells, and this response was not inhibitable by the addition of Q10-containing normal mouse serum. It is unlikely that this CTL activity is due to possible polymorphic differences in Q10 alleles, since semisyngeneic BALB/c (H-2d) mice, from which the Q10d hybrid gene construct was derived, are able to generate anti-Q10d effector cells. The Q10d molecule was shown to cross-react with H-2Ld, lending support to the concept that Qa genes can serve as donors for polymorphic sequences found in H-2K, -D, and -L. That mice can generate anti-Q10 CTL activity suggests that this soluble class I protein does not act as a toleragen for these cells. The implications of these findings for an understanding of self-tolerance are discussed.     

Demographic Trends of Aging — Application to Gerodontology1

Aging of the global world population both in developed and developing countries, an unbalanced male-female ratio within this elderly population, increasing populations – including elderly – within urban areas, all will have a marked effect on the practice of dentistry. Furthermore, major epidemiological changes occurring in the dental field, including an increasing dentition life expectancy, increasing root caries prevalence, decreasing coronal caries rates in children, and the relative increase in the prevalence of periodontal problems will have further impact on the dental care system. Major changes need to be anticipated both at the level of the care provider, including the dentist, the hygienist and the dental assistant, and at the level of the potential patient, especially among the geriatric population, if the profession is to be prepared to adequately address these issues.     

Expression of a Clostridium thermocellum endoglucanase gene in Lactobacillus plantarum

Recombinant plasmid pM25 containing the celE gene of Clostridium thermocellum, which codes for an enzymatically active endoglucanase, was transformed into Lactobacillus plantarum by electroporation. Strains harboring pM25 expressed thermostable endoglucanase, which was found predominantly in the culture medium. Two other plasmids, pGK12 and pSA3, were transformed into L. plantarum, and the stability of each plasmid was evaluated.     

Cell attachment properties of collagen type VI and arg-gly-asp dependent binding to its α2(VI) and α3(VI) chains

Twelve of sixteen different cell types including fibroblasts and tumor cells were able to attach and spread on substrates of pepsin-solubilized or intact collagen VI, and on its triple helical domain. Attachment and spreading were independent of soluble mediator proteins (fibronectin, laminin) and collagen VI was distinct from collagens I, IV and V in the cells with which it interacted. Many of the same cells bound and spread on substrates prepared from unfolded α2(VI) and α3(VI) chains but not on the α1(VI) chain. The interactions with the chains were inhibited by low concentrations (10–100 μM) of synthetic RGDS and RGDT but not RGES peptides while the binding of cells to pepsin-solubilized collagen VI was more than 20-fold less sensitive to these peptides. The data incidate that cells have the ability to bind to collagen VI in a specific manner suggesting a similar function for collagen VI in situ.     

Tired,weak, or in need of rest: fatigue among general practice attenders.

OBJECTIVES--To determine the prevalence and associations of symptoms of fatigue. DESIGN--Questionnaire survey. SETTING--London general practice. PARTICIPANTS--611 General practice attenders. MAIN OUTCOME MEASURES--Scores on a fatigue questionnaire and reasons given for fatigue. RESULTS--10.2% Of men (17/167) and 10.6% of women (47/444) had substantial fatigue for one month or more. Age, occupation, and marital status exerted minor effects. Subjects attributed fatigue equally to physical and non-physical causes. Physical ill health, including viral infection, was associated with more severe fatigue. Women rather than men blamed family responsibilities for their fatigue. The profile of persistent fatigue did not differ from that of short duration. Only one person met criteria for the chronic fatigue syndrome. CONCLUSIONS--Fatigue is a common complaint among general practice attenders and can be severe. Patients may attribute this to physical, psychological, and social stress.     

A third class I major histocompatibility complex antigen encoded by a gene in the D region of the H-2 d haplotype recognized by cytotoxic T lymphocytes

The D region of the H-2 ^d haplotype contains five class I genes: H-2D ^d , D2 ^d , D3 ^d , D4 ^d and H-2L ^d . Although previous studies have suggested the presence of D-end encoded class I molecules in addition to H-2D^d and H-2L^d, segregation of genes encoding such molecules has not been demonstrated. In this report we have used cãtotoxic T lymphocytes (CTL) to examine the D region of the H-2 ^d haplotype for the presence of additional class I molecules. CTL generated in (C3H × B6.K1)F₁ (K ^k D ^k , K ^b D ^b ) mice against the hybrid class I gene product Q10^d/L^d expressed on L cells cross-react with H-2L^d but not H-2D^d molecules, as determined by lysis of transfected cells expressing H-2L^d but not H-2D^d. Although H-2L^d-specific monoclonal antibodies (mAb) completely inhibit H-2L^d-specific CTL from killing B10.A(3R) (K ^b D ^d L ^d ) target cells, only partial inhibition of anti-Q10 CTL-mediated lysis was observed, suggesting the presence of an additional D-end molecule as a target for these latter CTL. To identify the region containing the gene encoding the Q10 cross-reactive molecule, we show that anti-Q10 CTL lyse target cells from a D-region recombinant strain B10.RQDB, which has H-2D ^d , D2 ^d , D3 ^d , D4 ^d , and H-2D ^b but not the H-2L ^d H-2 ^d , and H-2L ^d (including D2 ^d , D3 ^d , and D4 ^d , lacks this anti-Q10 CTL target molecule. Together, these data demonstrate that a class I gene mapping between H-2D ^d and H-2L ^d encodes an antigen recognozed by anti-Q10 CTL. A likely candidate for this gene is D2 ^d , D3 ^d or D4 ^d .     

Blood lipid concentrations and other cardiovascular risk factors: distribution,prevalence, and detection in Britain

To establish the distribution of blood lipid concentrations and the prevalences of other risk factors for cardiovascular disease in Britain 12 092 men and women aged 25-59 in Glasgow, Leicester, London, and Oxford were studied. Subjects were selected by opportunistic case finding, in which patients consulting their general practitioner for any reason were offered a health check by appointment, or random selection from age-sex registers, in which an invitation for a health check was posted. The overall rate of response was 73%, being 91-94% by opportunistic case finding and 36-63% by random selection. At the health check subjects answered a brief questionnaire about risk factors for cardiovascular disease, and their height, weight, and blood pressure were recorded; a blood sample was taken for measuring plasma concentrations of cholesterol, triglyceride, high density lipoprotein cholesterol, and glucose.The mean cholesterol concentrations were 5·9 (SD 1·2) and 5·8 (1·2) mmol/l in men and women, respectively. In London the mean value was 5·5 (1·2) mmol/l for both men and women and was significantly lower than mean values in the three other centres, among which there were no significant differences. In men and women aged 25-29 concentrations were similar but they increased in men until the age of 45-49, after which they showed no further increase; in women concentrations did not increase until the age of 40-44 and by the age of 50-59 values were higher than in men. Mean triglyceride concentrations were significantly higher in men than in women (1·8 (1·4) v 1·3 (0·9) mmol/l, respectively), and trends with age were similar to those for cholesterol concentrations, except that at no age were values higher in women than in men. Mean triglyceride values overall were higher in Glasgow and London than in Oxford and Leicester. Body mass index was higher in Glasgow and London than in the other two centres and correlated with systolic and diastolic blood pressures and triglyceride concentration. In addition, subjects in Glasgow smoked significantly more than those in the other centres. These observations could contribute to the higher rate of coronary heart disease in Glasgow. Plasma lipid concentrations and the prevalences of other risk factors for cardiovascular disease were similar in subjects selected by opportunistic case finding and by random selection.In Britain cholesterol values have changed little during the past 12 years despite dietary recommendations and health education. Identifying subjects at particularly high risk of coronary heart disease is required to supplement advice to the general population to reduce the prevalence of this disease. Opportunistic case finding would be an appropriate method of identifying such subjects in general practice, although none of the potential markers for hyperlipidaemia was particularly useful in identifying all subjects at high risk.     

Histone H3 N-terminal mutations allow hyperactivation of the yeast GAL1 gene in vivo.

Recent work has shown that the yeast histone H4 N-terminus, while not essential for viability, is required for repression of the silent mating loci and activation of GAL1 and PHO5 promoters. Because histone H3 shares many structural features with histone H4 and is intimately associated with H4 in the assembled nucleosome, we asked whether H3 has similar functions. While the basic N-terminal domain of H3 is found to be non-essential (deletion of residues 4-40 of this 135 amino acid protein allows viability), its removal has only a minor effect on mating. Surprisingly, both deletions (of residues 4-15) and acetylation site substitutions (at residues 9, 14 and 18) within the N-terminus of H3 allow hyperactivation of the GAL1 promoter as well as a number of other GAL4-regulated genes including GAL2, GAL7 and GAL10. To a limited extent glucose repression is also alleviated by H3 N-terminal deletions. Expression of another inducible promoter, PHO5, is shown to be relatively unaffected. We conclude that the H3 and H4 N-termini have different functions in both the repression of the silent mating loci and in the regulation of GAL1.