Possible role of metal ionophore against zinc induced cognitive dysfunction in <Emphasis Type="SmallCaps">d-</Emphasis>galactose senescent mice

Metal ionophores are considered as potential anti-dementia agents, and some are currently undergoing clinical trials. Many metals are known to accumulate and distribute abnormally in the aging brain. Alterations in zinc metal homeostasis in the glutaminergic synapse could contribute to ageing and the pathophysiology of Alzheimer’s disease (AD). The present study was designed to investigate the effect of metal ionophores on long term administration of zinc in D-galactose induced senescent mice. The ageing model was established by combined administration of zinc and D-galactose to mice for 6 weeks. A novel metal ionophore, PBT-2 was given daily to zinc-induced d-galactose senescent mice. The cognitive behaviour of mice was monitored using the Morris Water Maze. The anti-oxidant status and amyloidogenic activity in the ageing mouse was measured by determining mito-oxidative parameters and deposition of amyloid β (Aβ) in the brain. Systemic administration of both zinc and D-galactose significantly produced memory deficits, mito-oxidative damage, heightened acetylcholinesterase enzymatic activity and deposition of amyloid-β. Treatment with PBT-2 significantly improved behavioural deficits, biochemical profiles, cellular damage, and curbed the deposition of APP in zinc-induced senescent mice. These findings suggest that PBT-2, acting as a metal protein attenuating compound, may be helpful in the prevention of AD or alleviation of ageing.     

Differential regulation of the brain and gut immunoreactive dynorphin by the serotonin system

Administration of drugs such as fenfluramine, 20-40 mg/kg, and m-chlorophenylpiperazine (m-CPP), 2.5-5 mg/kg, which release serotonin or activate postsynaptic serotonin receptors, respectively, induced a dramatic decrease in the duodenal content of immunoreactive dynorphin (ir-DYN). The effect was antagonized by cyproheptadine, 1 mg/kg. Similarly, acute administration of the specific serotonin reuptake blockers fluvoxamine, 15 mg/kg, or femoxetine, 10 mg/kg, and 5-hydroxytryptophan (5-HTP), 40-160 mg/kg, evoked a marked decrease in the duodenal content of ir-DYN. A combined administration of fluvoxamine or femoxetine and 5-HTP failed to potentiate the effect of individual treatment. Only a higher dose of fenfluramine, 40 mg/kg, increased the ir-DYN content in the hypothalamus. These results suggest that the brain and gut ir-DYN is independently regulated by the serotonin system and that a serotonin mechanism might stimulate release of the gut dynorphin content.     

Histopathology of retained bovine fetal membranes

Placentomes were obtained from 20 cows with retained placenta (9 following normal birth, 5 after abortion and 6 with dystocia), and this material was examined by light microscopy. Histologic changes that were consistently seen in placentomes of cows with retained placenta after normal birth included vascular changes (edema, thrombosis and vasculitis) and the presence of numerous clumps of bacterialcolonies in the connective tissue of the caruncles and cotyledons. Only a few binucleate cells were seen in these cases. In placentomes obtained from cows with retained placenta after abortion, there were instances of focal necrosis of the fetal villi and the presence of variable numbers of binucleate cells. Vascular changes and numerous clumps of bacterial colonies in the caruncles and cotyledons were also noted. The changes in placentomes obtained from cows with retained placenta and dystocia included the presence of numerous binucleate cells, infiltration of polymorphonuclear cells in the connective tissue of both the fetal and maternal villi, vascular changes, and the presence of extensive necrosis and numerous clumps of bacterial colonies. Significant differences (P < 0.05) were encountered in the number of binucleate cells in the various groups. Binucleate cells appear to be involved in the process of placental separation in cows with retained placenta.     

Using patient and general practice characteristics to explain variations in cervical smear uptake rates.

OBJECTIVES--To produce practice and patient variables for general practices from census and family health services authority data, and to determine the importance of these variables in explaining variation in cervical smear uptake rates between practices. DESIGN--Population based study examining variations in cervical smear uptake rates among 126 general practices using routine data. SETTING--Merton, Sutton, and Wandsworth Family Health Services Authority, which covers parts of inner and outer London. MAIN OUTCOME MEASURE--Percentage of women aged 25-64 years registered with a general practitioner who had undergone a cervical smear test during the five and a half years preceding 31 March 1992. RESULTS--Cervical smear uptake rates varied from 16.5% to 94.1%. The estimated percentage of practice population from ethnic minority groups correlated negatively with uptake rates (r = -0.42), as did variables associated with social deprivation such as overcrowding (r = -0.42), not owning a car (r = -0.41), and unemployment (r = -0.40). Percentage of practice population under 5 years of age correlated positively with uptake rate (r = 0.42). Rates were higher in practices with a female partner than in those without (66.6% v 49.1%; difference 17.5% (95% confidence interval 10.5% to 24.5%)), and in computerised than in non-computerised practices (64.5% v 50.5%; 14.0% (6.4% to 21.6%)). Rates were higher in larger practices. In a stepwise multiple regression model that explained 52% of variation, five factors were significant predictors of uptake rates: presence of a female partner; children under 5; overcrowding; number of women aged 35-44 as percentage of all women aged 25-64; change of address in past year. CONCLUSIONS--Over half of variation in cervical smear uptake rates can be explained by patient and practice variables derived from census and family health services authority data; these variables may have a role in explaining variations in performance of general practices and in producing adjusted measures of practice performance. Practices with a female partner had substantially higher uptake rates.     

Evaluation of Salmonella Porins as a Broad Spectrum Vaccine Candidate

Porins were prepared from smooth strain of Salmonella typhi 0–901 and chemotype of rough mutant of S. typhimurium Ra-30. Mice were immunized with both the porin preparations in different groups and challenged with S. typhimurium LT2–71 and S. enteritidis SH-1269. Porin immunized mice showed significant protection (P <0.01) against challenge with homologous as well as heterologous strains. Hence, the use of porins may be attempted in future to protect against salmonellosis.     

Molecular cloning and analysis of CDC28 and cyclin homologues from the human fungal pathogen Candida albicans

In the budding yeast Saccharomyces cerevisiae, progress of the cell cycle beyond the major control point in G1 phase, termed START, requires activation of the evolutionarily conserved Cdc28 protein kinase by direct association with GI cyclins. We have used a conditional lethal mutation in CDC28 of S. cerevisiae to clone a functional homologue from the human fungal pathogen Candida albicans. The protein sequence, deduced from the nucleotide sequence, is 79% identical to that of S. cerevisiae Cdc28 and as such is the most closely related protein yet identified. We have also isolated from C. albicans two genes encoding putative G1 cyclins, by their ability to rescue a conditional GI cyclin defect in S. cerevisiae; one of these genes encodes a protein of 697 amino acids and is identical to the product of the previously described CCN1 gene. The second gene codes for a protein of 465 residues, which has significant homology to S. cerevisiae Cln3. These data suggest that the events and regulatory mechanisms operating at START are highly conserved between these two organisms.     

Enterotoxigenic aeromonads on retail lamb meat and offal

Enrichment in alkaline peptone water was compared with the direct plating method for the isolation of Aeromonas spp. from lamb meat and offal samples. The enrichment method significantly increased the isolation rate of aeromonads. Motile Aeromonas species (A. hydrophila, A. sobria and A. caviae) were present in all kinds of samples investigated. Seventy-three Aeromonas strains isolated in this survey were characterized to species level and examined for their ability to produce virulence factors. Strains identified as A. sobria were the strongest producers of haemolysin and enterotoxin, whereas A. caviae strains were consistently non-haemolytic and non-enterotoxigenic. Thus it is likely that lamb meat and offal are potentially significant sources of virulent Aeromonas species and may play an important role in the aetiology of Aeromonas-associated gastro-enteritis.     

Deprivation payments to general practitioners: limitations of census data.

The census data from which deprivation payments have been calculated since June 1995 suffer from limitations including underenumeration; under counting of homeless people and refugees, and artefactual errors because of the way in which the 1991 census data were tabulated. These limitations reduced the fairness of the changes that many practices experienced in their deprivation payments. The validity of the current system of deprivation payments would be improved if these limitations were borne in mind when allocating payments to practices and if enumeration districts were used as the basis of payments rather than electoral wards.     

Effects of microbial volatile organic compounds on Ganoderma lucidum growth and ganoderic acids production in Co-v-cultures (volatile co-cultures)

Abstract

Co-v-culture (co-cultivations of physically separated microbes that only interact through the air) systems were designed to investigate the effects of microbial volatile organic compounds (mVOCs) from about 20 different microbes, on a medicinal fungus, Ganoderma lucidum. For more accuracy in co-cultivations, a novel synchronized cultivation approach was tested for culturing G. lucidum. The hyphal growth of G. lucidum and the content of its ganoderic acids (GAs) were measured. In almost all of the co-v-cultures, there was an inhibiting effect on hyphal growth and a promoting effect on GAs contents. In inducing GAs production, Bacillus cereus PTCC 1247 and Pseudomonas aeruginosa UTMC 1404 were the most effective ones, as, compared to control cultures, GAs content increased 2.8 fold. Comparing different co-v-cultivations demonstrated that the concentrations of mVOCs, oxygen, and carbon dioxide were the main players in co-v-cultures. No correlation was found between hyphal growth and GAs production. Strains of the same species imposed totally different effects on hyphal growth or GAs production. This study has investigated the effects of mVOCs on G. lucidum for the first time. Moreover, it suggests that co-v-cultivation may be a promising biotechnological approach to improve the production in G. lucidum.     

Methylmercury poisoning in Iraqi children: clinical observations over two years.

The clinical features of 49 children who had eaten bread contaminated with methylmercury in rural Iraq were reviewed. Symptoms and signs relating to the nervous system--varying degrees of ataxia, weakness, and visual and sensory changes--dominated the clinical picture. The severity of poisoning was related to the blood mercury concentration, as was the degree of recovery. Follow-up over two years showed that children who had had mild or moderate poisoning slowly but steadily improved, some of them recovering normal function, though all had a residual generalized hyperreflexia. In some patients ataxia and motor weakness disappeared. Visual changes also improved, though less completely, and of 17 blind children, only five had recovered partial sight by the end of two years. Seven of the 18 children who suffered very severe poisoning were left physically and mentally incapacitated. The degree of clinical progress shown by these children was better than that shown by some other groups of patients, possibly because the poisoning was relatively acute and mercury consumption was stopped immediately after its effects had become obvious.