Strikes, flooding, rats, and leptospirosis in Marseille, France

Objectives

The aim of this study was to examine the mechanisms by which weather conditions, the incidence of Leptospira in reservoir populations, and various socio-ecological factors are driving the emergence of leptospirosis in Marseille, France.

Methods

Over the last 30 years our laboratory has surveyed all human cases of leptospirosis in Marseille using clinical, epidemiological, serological, and molecular tools. Data for the weather conditions in Marseille were collected from the official meteorological station, and garbage management strikes were monitored through the local press. Rats were trapped in alleys near to where the patients may have acquired leptospirosis.

Results

Three new cases of autochthonous leptospirosis are reported. The global tendency for rainfall showed a slight increase over the period under analysis. The index case of leptospirosis occurred after a heavy rainfall with flooding. Over the last 10 years Marseille has undergone 82 days of garbage management strikes. Leptospira DNA was detected in two of 11 rats.

Conclusions

The emergence of leptospirosis has become a public health problem in Marseille, and is associated with a combination of heavy rainfall and garbage collection strikes in which garbage is left on the street and thereby contributes to the expansion of the rat population on the surface.     

Changes in Hypertension Prevalence,Awareness, Treatment,and Control in High-, Middle-, and Low-Income Countries: An Update

The aim of this paper was to critically evaluate recent publications on hypertension treatment and control in regions by income. Prevalence of hypertension is increasing worldwide, most prominently in low-income countries. Awareness, treatment, and control are most successful in North America while remaining a challenge in middle- and low-income countries. Easy access to medical care and aggressive use of pharmacotherapy are the key strategies which have proved to be successful in reducing the burden of hypertension on the population level.     

Sigma-receptors in endocrine organs: identification, characterization, and autoradiographic localization in rat pituitary, adrenal, testis, and ovary

We have used a variety of selective radioligands to identify and localize sigma- and phencyclidine (PCP)-binding sites in rat endocrine organs. [3H]Haloperidol-labeled sigma-receptors were identified in membrane homogenates of rat pituitary, adrenal, testis, and ovary which had kinetic and pharmacological characteristics similar to those of the well characterized sigma-receptors in rat cerebellum. The highest density of sigma-receptors was present in the ovary, with progressively lower densities present in the testis, pituitary, adrenal, and cerebellum, respectively. In autoradiographic studies, sigma-receptors [labeled with d-3-(3-hydroxyphenyl)N-(1-propyl-2,3-[3H]piperidine or [3H]1,3-di-(2-tolyl)guanidine] were discretely localized within the endocrine tissues. In the pituitary, the highest density of sigma-receptors was found in the anterior lobe. In the adrenal, sigma-receptors were localized primarily in the cortex. In the testis, sigma-receptors were present in highest concentrations in the ductuli efferentes and ductus epididymis; lower densities of binding sites were present in the seminiferous tubules, and no binding was seen in the interstitial tissue. In the ovary, sigma-receptors were localized in high density in the maturing follicles, and lower densities were present in resting follicles. After hypophysectomy, there were relative increases in the densities of sigma receptors in the remaining tissue in the adrenal gland and testis. In contrast, hypophysectomy resulted in a marked depletion of sigma-binding sites in the ovary. The data from hypophysectomized rats indicate that the highest densities of sigma-receptors in the ovary are localized to (LH-dependent) maturing follicles, while sigma-binding sites in adrenal and testis are localized to cells that are not dependent on trophic maintenance by the pituitary. In contrast, high affinity PCP receptors were not detected in pituitary, adrenal, testis, or ovary either by homogenate binding studies with 3,4-[3H]N-[1-(2-thienyl)cyclohexyl]piperidine or in vitro autoradiography using 3,4-[3H]N-[1-(2-thienyl)cyclohexyl]piperidine and d-[3H]5-methyl-10,11-dihydro-5H-dibenzo-[a,d] + cyclohepten-5,10-imine. In summary, the data suggest that the reported endocrine effects of PCP and the prototypic sigma-receptor agonist N-allylnormetazocine are probably mediated either through direct action on sigma-receptors in the pituitary and/or target endocrine organs or by actions on sigma- and/or PCP receptors in brain.     

Rickettsia, Ehrlichia, Anaplasma, and Bartonella in ticks and fleas from dogs and cats in Bangkok

Flea and tick specimens (5-10 fleas or ticks) on dogs and cats from various sites in Bangkok were tested by polymerase chain reaction and DNA sequencing to detect DNA of bacteria Rickettsia (gltA and 17?kDa genes), Anaplasmataceae (16S rRNA gene), and Bartonella (pap31 and its genes). We confirmed that Rickettsia sp. related to Rickettsia felis was detected in 66 of 98 (67.4%) flea specimens from dogs, whereas 8 Bartonella henselae and 2 Bartonella clarridgeiae were detected in 10 of 54 (18.5%) flea specimens from cats. Further, this work provides the first evidence of 10 Ehrlichia canis (3.3%), 7 Anaplasma platys (2.3%), and 2 Wolbachia spp. (0.66%) in 304 Rhipicephalus sanguineus tick specimens in Thailand.     

Heterogeneity in expression and subcellular localization of claudins 2, 3, 4, and 5 in the rat liver, pancreas, and gut

BACKGROUND & AIMS: Paracellular transport varies widely among epithelia of the gastrointestinal tract. We determined whether members of the claudin family of tight junction proteins are differentially expressed consistent with a potential role in creating these variable properties. METHODS: Rabbit polyclonal antibodies were produced against peptides from claudins 2 through 5. The distribution of individual claudins was detected by immunoblotting, and their cell type and subcellular localization were determined by immunofluorescence on cryosections of rat liver, pancreas, stomach, and small and large intestine. RESULTS: All antibodies detected single bands of the expected size on immunoblots and were monospecific based on peptide competition studies. Immunoblotting detected strong differences among tissues in the expression level of each claudin. Immunolocalization confirmed these differences and revealed striking variations in expression patterns. In the liver, claudin 2 shows a lobular gradient increasing from periportal to pericentral hepatocytes, claudin 3 is uniformly expressed, claudin 4 is absent, and claudin 5 is only expressed in endothelial junctions. In the pancreas, claudin 2 is only detected in junctions of the duct epithelia, claudin 5 only in junctions of acinar cells, whereas claudin 3 and 4 are in both. Among differences in the gut are a crypt-to-villus decrease in claudin 2, a highly restricted expression of claudin 4 to colonic surface cells, and the finding that some claudins can be junctional, lateral, or show a gradient in junctional vs. lateral localization along the crypt-to-villus surface axis. CONCLUSIONS: Claudins have very different expression patterns among and within gastrointestinal tissues. We propose these patterns underlie differences in paracellular permeability properties, such as electrical resistance and ion selectivity that would complement known differences in transcellular transport.     

Strategy use, recall, and recall organization in young, middle-aged, and elderly adults

The application and transfer of free recall study strategies were examined for young, middle-aged, and elderly adults. Subjects were either instructed to use clustering and imagery, instructed to use their own study strategies, or given standard free recall instructions. Subjects at all age levels showed high initial use of categorization and low initial use of imagery. Subject-reported imagery increased after training, but categorization was the only strategy associated with higher recall levels. Training produced increases in recall clustering that were apparent only on a transfer list. The results provided evidence that adult age differences in memory occur even when middle-aged and elderly adults show evidence of categorization in recall.     

Strategy use,recall, and recall organization in young,middle-aged,and elderly adults

Abstract

The application and transfer of free recall study strategies were examined for young, middle-aged, and elderly adults. Subjects were either instructed to use clustering and imagery, instructed to use their own study strategies, or given standard free recall instructions. Subjects at all age levels showed high initial use of categorization and low initial use of imagery. Subject-reported imagery increased after training, but categorization was the only strategy associated with higher recall levels. Training produced increases in recall clustering that were apparent only on a transfer list. The results provided evidence that adult age differences in memory occur even when middle-aged and elderly adults show evidence of categorization in recall.     

Ethanol, Calcium, and Naloxone in Mice

Alcohol has been reported to produce a significant reduction in the brain calcium content of rats, which could be blocked by administration of naloxone. Ethanol pretreatment failed to decrease brain cortex calcium and, in fact, increased the calcium content at higher doses. The effects of naloxone were also studied.     

Variability, compensation, and modulation in neurons and circuits

I summarize recent computational and experimental work that addresses the inherent variability in the synaptic and intrinsic conductances in normal healthy brains and shows that multiple solutions (sets of parameters) can produce similar circuit performance. I then discuss a number of issues raised by this observation, such as which parameter variations arise from compensatory mechanisms and which reflect insensitivity to those particular parameters. I ask whether networks with different sets of underlying parameters can nonetheless respond reliably to neuromodulation and other global perturbations. At the computational level, I describe a paradigm shift in which it is becoming increasingly common to develop families of models that reflect the variance in the biological data that the models are intended to illuminate rather than single, highly tuned models. On the experimental side, I discuss the inherent limitations of overreliance on mean data and suggest that it is important to look for compensations and correlations among as many system parameters as possible, and between each system parameter and circuit performance. This second paradigm shift will require moving away from measurements of each system component in isolation but should reveal important previously undescribed principles in the organization of complex systems such as brains.     

Sex,prions, and plasmids in yeast

Even deadly prions may be widespread in nature if they spread by infection faster than they kill off their hosts. The yeast prions [PSI+] and [URE3] (amyloids of Sup35p and Ure2p) were not found in 70 wild strains, while [PIN+] (amyloid of Rnq1p) was found in ∼16% of the same population. Yeast prion infection occurs only by mating, balancing the detrimental effects of carrying the prion. We estimated the frequency of outcross mating as about 1% of mitotic doublings from the known detriment of carrying the 2-μm DNA plasmid (∼1%) and its frequency in wild populations (38/70). We also estimated the fraction of total matings that are outcross matings (∼23–46%) from the fraction of heterozygosity at the highly polymorphic RNQ1 locus (∼46%). These results show that the detriment of carrying even the mildest forms of [PSI+], [URE3], or [PIN+] is greater than 1%. We find that Rnq1p polymorphisms in wild strains include several premature stop codon alleles that cannot propagate [PIN+] from the reference allele and others with several small deletions and point mutations which show a small transmission barrier. Wild strains carrying [PIN+] are far more likely to be heterozygous at RNQ1 and other loci than are [pin−] strains, probably reflecting its being a sexually transmitted disease. Because sequence differences are known to block prion propagation or ameliorate its pathogenic effects, we hypothesize that polymorphism of RNQ1 was selected to protect cells from detrimental effects of the [PIN+] prion.