Diversity of bat-associated Leptospira in the Peruvian Amazon inferred by bayesian phylogenetic analysis of 16S ribosomal DNA sequences

The role of bats as potential sources of transmission to humans or as maintenance hosts of leptospires is poorly understood. We quantified the prevalence of leptospiral colonization in bats in the Peruvian Amazon in the vicinity of Iquitos, an area of high biologic diversity. Of 589 analyzed bats, culture (3 of 589) and molecular evidence (20 of 589) of leptospiral colonization was found in the kidneys, yielding an overall colonization rate of 3.4%. Infection rates differed with habitat and location, and among different bat species. Bayesian analysis was used to infer phylogenic relationships of leptospiral 16S ribosomal DNA sequences. Tree topologies were consistent with groupings based on DNA-DNA hybridization studies. A diverse group of leptospires was found in peri-Iquitos bat populations including Leptospira interrogans (5 clones), L. kirschneri (1), L. borgpetersenii (4), L. fainei (1), and two previously undescribed leptospiral species (8). Although L. kirschenri and L. interrogans have been previously isolated from bats, this report is the first to describe L. borgpetersenii and L. fainei infection of bats. A wild animal reservoir of L. fainei has not been previously described. The detection in bats of the L. interrogans serovar Icterohemorrhagiae, a leptospire typically maintained by peridomestic rats, suggests a rodent-bat infection cycle. Bats in Iquitos maintain a genetically diverse group of leptospires. These results provide a solid basis for pursuing molecular epidemiologic studies of bat-associated Leptospira, a potentially new epidemiologic reservoir of transmission of leptospirosis to humans.     

Influence of risk factors on renal leptospiral load in naturally infected wild black rats

In 2009, a survey was conducted in Reunion Island to determine the renal leptospiral load in black rats trapped in the field. The concentration of leptospires in kidney tissue was calculated using qPCR. Our results showed high inter-individual variations of renal bacterial load in naturally infected black rats (mean = 8.27 ± 4.72 log-genome copies per mg kidney tissue). The objective of this study was to model the renal leptospiral load in 50 naturally infected black rats as a function of sex, age, and weight. Statistical analysis by sex showed that, in naturally infected males, the renal leptospiral load was correlated with weight (p-value = 0.032). Moreover, our model showed that weight and sex were significant explanatory variables for the renal leptospiral load in naturally infected young black rats (R² = 0.953). Laboratory experimentation could not replicate naturally acquired infection, but field studies also present many limitations. Our study is the first attempt to explain individual variations in the renal leptospiral load in naturally infected reservoir animals but further research is needed.     

Maximizing the chances of detecting pathogenic leptospires in mammals: the evaluation of field samples and a multi-sample-per-mammal, multi-test approach

Identification of wild animals that harbour the causative leptospires, and the identification of the most important of these 'wild reservoirs' (in terms of threat to human health), are key factors in the epidemiology of human leptospirosis. In an epidemiological investigation in the Australian state of Queensland, in 2007-2008, samples were collected from fruit bats (Pteropus conspicillatus) and rodents (to investigate the potential role of fruit bats in the maintenance and transmission of leptospires to ground-dwelling rodents) and checked for pathogenic leptospires. The results of these studies have now been carefully analysed in attempts to see which method of detection and type of test sample were best. The effects of pentobarbitone sodium used to euthanize wild mammals before collection of necropsy samples, on the survival and detection of leptospires in vitro, were also explored. In the earlier field investigation, serum, renal tissue and urine were collected from wild mammals, for the detection of pathogenic leptospires by culture, the microscopic agglutination test (MAT), real-time PCR and silver impregnation of smears. Although 27.6% of the rodents investigated were found leptospire-positive, culture only yielded four isolates, probably because many cultures were contaminated. The main aims of the present study were to quantify the performance of the individual diagnostic tests and examine the reasons behind the high incidence of culture contamination. The results of sensitivity and specificity analyses for the different diagnostic tests indicated that isolation by culture (the definitive diagnostic test for leptospiral shedding) had perfect (100%) sensitivity when compared with the results of the PCR but a low specificity (40%). The MAT performed poorly, with a sensitivity of 50% when compared against the results of culture. The prevalence of leptospiral carriage revealed by the PCR-based investigation of kidney and urine samples (59.2%) was higher than that revealed using any other method and far higher than the 2.0% revealed by culture. The results of the culture of renal tissue agreed fairly well with those of the PCR-based investigation of such tissue, with a Cohen's unweighted kappa coefficient (κ) of 0.5 (P = 0.04). The levels of agreement between other pairs of tests were generally poor. The presence of pentobarbitone sodium, at final concentrations of 27.8 or 167 mg/ml, did not affect the viability or the detection of leptospires in culture, and is therefore unlikely to reduce the chances of isolating leptospires from an animal that has been euthanized with the compound. It appears that collecting multiple samples from each mammal being checked will improve the chances of detecting leptospires (and reduce the chances of reporting an inconclusive result for any of the mammals). For the identification of a leptospiral carrier, however, the use of just two detection methods (culture and PCR) and one type of sample (renal tissue) may give adequate sensitivity and specificity. Given the robustness of PCR to contamination and its high sensitivity (it can give a positive result when DNA from just two leptospiral cells is present in the sample), a PCR-based serotyping method, to allow the combined detection and characterisation of leptospires from field isolates, would be extremely useful.     

Survey of leptospirosis of small mammals in Thailand

During 1999-2000, kidney tissues of approximately 15% of 1310 rodents trapped from northeastern provinces of Thailand were tested for the presence of leptospires. Our direct immunofluorescent assay (DFA) for detection of leptospires showed 100% sensitivity and 94% specificity with the culture data. Both methods identified R. norvegicus as the highest source of infection. Among isolated Leptospira, 137 were serotyped by cross agglutinin absorption and/or a microscopic agglutination, and gave some variations and similarities at the serovar level to the DFA results. DFA data demonstrated over half of the positive animals were infected with several serovars of Leptospira interrogans. A subsequent DFA study in Bangkok in 2002 revealed leptospiral infection in 33% of 42 rats and shrews. The most common infecting serovars were Autumnalis and Canicola identified in rural and urban animals, respectively. This finding suggests that wild small mammals may act as important sources of pathogenic leptospires and warrant active surveillance to understand the epidemiology of transmission and control of carrier animals.     

The role of fruit bats in the transmission of pathogenic leptospires in Australia

Although antileptospiral antibodies and leptospiral DNA have been detected in Australian fruit bats, the role of such bats as infectious hosts for the leptospires found in rodents and humans remains unconfirmed. A cohort-design, replicated survey was recently conducted in Far North Queensland, Australia, to determine if the abundance and leptospiral status of rodents were affected by association with colonies of fruit bats (Pteropus conspicillatus spp.) via rodent contact with potentially infectious fruit-bat urine. In each of four study areas, a 'colony site' that included a fruit-bat colony and the land within 1500 m of the colony was compared with a 'control site' that held no fruit-bat colonies and was >2000 m from the nearest edge of the colony site. Rodents were surveyed, for a total of 2400 trap-nights, over six sampling sessions between September 2007 and September 2008. A low abundance of rodents but a high carriage of leptospires in the rodents present were found to be associated with proximity to a fruit-bat colony. For example, means of 0·4 and 2·3 fawn-footed melomys (Melomys cervinipes) were collected/100 trap-nights at sites with and without fruit-bat colonies, respectively (P<0·001), but the corresponding prevalences of leptospiral carriage were 100% and 3·6% (P<0·001). Such trends were consistent across all of the sampling sessions but not across all of the sampling sites. Leptospires were not isolated from fruit bats by culture, and the role of such bats in the transmission of leptospires to rodents cannot be confirmed. The data collected do, however, indicate the existence of a potential pathway for transmission of leptospires from fruit bats to rodents, via rodent contact with infectious fruit-bat urine. Fruit bats may possibly be involved in the ecology of leptospires (including emergent serovars), as disseminators of pathogens to rodent populations. Stringent quantitative risk analysis of the present and similar data, to explore their implications in terms of disease prevalence and wildlife population dynamics, is recommended.     

X-linked locus associated with hypertensive renal disease susceptibility in Dahl rats

OBJECTIVE: There is increasing evidence that genetic factors contribute to renal disease susceptibility associated with essential hypertension. To what extent these genetic factors act independently of hypertension susceptibility remains undetermined. The present study was undertaken to assess the potential chromosome X influence on target organ renal disease in the Dahl rat model of salt-sensitive hypertension. SUBJECTS AND METHODS: Dahl S, Dahl R, F1(RXS), F1(SXR) and F2(RXS) rat male populations were phenotyped for hypertensive renal disease by measuring the percent of incidence of the Grade IV Raij renal pathology score. Six chromosome X markers informative for our (RXS) intercross were analyzed in our F2 rat population (n = 105) for co-segregation with hypertensive renal disease and blood pressure characterized by radiotelemetry. RESULTS: Comparison of the incidence of renal disease (histologically determined) between F1 reciprocal intercross male progenies reveals a significant chromosome X effect on renal disease [percent incidence of Grade IV Raij renal pathology score in F1 (R female S male) male rats = 2.75 +/- 0.66, and in F1 (S female R male) male rats = 0.67 +/- 0.42; = 0.02]. QTL analysis on an F2(RXS) male population phenotyped for renal disease susceptibility (percent incidence of Grade IV Raij renal pathology score) detects significant linkage to DXRat98 (likelihood ratio statistic = 9.4, P = 0.00223) on chromosome X, corroborating X-linkage of renal disease susceptibility in Dahl rats. CONCLUSIONS: Our results demonstrate the existence of an X-linked locus associated with hypertensive renal disease susceptibility in Dahl rats. Furthermore, the chromosome X markers tested did not co-segregate with hypertension, indicating that the gene(s) on chromosome X influence renal disease susceptibility independent of blood pressure.     

Prevalence of feline leptospirosis: serologic survey and attempts of isolation and demonstration of the agent

The occurrence of leptospiral infection in cats was determined through the detection of specific antibodies based on the results of microscopic agglutination test and the attempts of isolation and histological demonstration of leptospires from the kidneys of these animals. Of 172 serum samples examined by microscopic agglutination test, 22 (12.8%) were positive with titers greater than or equal to 100. The most frequent serovar was pomona. In relation to the sex, significant differences were not seen; however the age distribution showed that feline leptospirosis is more frequent in adult cats. The attempts for isolation and demonstration of L. interrogans from renal parenchyma by culture or Warthin Starry technics were unsuccessful.     

Diabetic nephropathy and long-term treatment effects of rosiglitazone and enalapril in obese ZSF1 rats

Diabetic nephropathy (DN) is a major cause of end-stage renal disease. Yet the pathogenic mechanisms underlying the development of DN are not fully defined, partially due to lack of suitable models that mimic the complex pathogenesis of renal disease in diabetic patients. In this study, we describe early and late renal manifestations of DN and renal responses to long-term treatments with rosiglitazone or high-dose enalapril in ZSF1 rats, a model of metabolic syndrome, diabetes, and chronic renal disease. At 8 weeks of age, obese ZSF1 rats developed metabolic syndrome and diabetes (hyperglycemia, glucosuria, hyperlipidemia, and hypertension) and early signs of renal disease (proteinuria, glomerular collagen IV deposition, tubulointerstitial inflammation, and renal hypertrophy). By 32 weeks of age, animals developed renal histopathology consistent with DN, including mesangial expansion, glomerulosclerosis, tubulointerstitial inflammation and fibrosis, tubular dilation and atrophy, and arteriolar thickening. Rosiglitazone markedly increased body weight but reduced food intake, improved glucose control, and attenuated hyperlipidemia and liver and kidney injury. In contrast, rosiglitazone markedly increased cardiac hypertrophy via a blood pressure-independent mechanism. High-dose enalapril did not improve glucose homeostasis, but normalized blood pressure, and nearly prevented diabetic renal injury. The ZSF1 model thus detects the clinical observations seen with rosiglitazone and enalapril in terms of primary and secondary endpoints of cardiac and renal effects. This and previous reports indicate that the obese ZSF1 rat meets currently accepted criteria for progressive experimental diabetic renal disease in rodents, suggesting that this may be the best available rat model for simulation of human DN.     

Diarrhea caused by enterotoxigenic Escherichia coli infection of humans is inhibited by dietary calcium

BACKGROUND & AIMS: In several rat infection experiments, we have shown that dietary calcium inhibits intestinal colonization and translocation of invasive salmonella. The aim of the present study was to find out whether calcium is also protective against enterotoxigenic Escherichia coli (ETEC) infection. This was first tested in our rat model and subsequently verified in a human infection study. METHODS: Rats were fed a purified diet with either a low or a high amount of calcium phosphate and orally infected with ETEC. In addition, a parallel, double-blind, placebo-controlled intervention study of 3 weeks was performed with 32 healthy men. Subjects largely maintained their habitual diet and consumed either regular milk products (calcium supply, 1100 mg/day) or placebo milk products (calcium supply, 60 mg/day). On day 10, subjects ingested a live but attenuated ETEC strain (strain E1392/75-2A), able to induce mild although short-lived symptoms. Primary outcomes studied were infection-induced diarrhea (total fecal output and relative fecal dry weight) and fecal mucin excretion. RESULTS: In humans, ETEC induced diarrhea in both groups, in that total fecal output doubled and mean relative fecal dry weight dropped from 25% to 20%. Additionally, fecal mucin excretion was increased in both groups. All these fecal parameters were completely normalized in the calcium group on the second infection day, in contrast to the placebo group, which recovered on the third infection day. Likewise, supplemental calcium inhibited ETEC colonization and diarrhea in rats. CONCLUSIONS: Calcium in milk products improves human resistance to ETEC infection as it inhibits infectious diarrhea.     

Prevalence and genetic divergence of Leptospira interrogans and Leptospira borgpetersenii in house rats(Rattus rattus) from Peninsular Malaysia

Objective: To evaluate the prevalence and divergence of genetically identified Leptospira spp. in the population of Rattus rattus.Methods: A total of 130 rats were used in this study. The infection within the rats were screened using polymerase chain reaction(PCR)-based diagnosis, with Leptospira genusspecific 16 S r RNA primer and pathogenic Leptospira spp. specific Lip L32 primer, on both kidney and liver tissues of Rattus rattus to detect the presence of potential Leptospira spp.Results: Out of 130 rats studied, 51(39.23%) individuals were positive for leptospiral DNA. Basic Local Alignment Search Tool(BLAST) and phylogenetic analysis revealed that both pathogenic Leptospira interrogans and Leptospira borgpetersenii were predominantly identified. Phylogenetically, both genes disclosed similar clustering patterns of tree topologies between the two species. Although both genes were conserved, Lip L32 gene portrayed higher nucleotide divergence(5.80%) compared to the 16 S r RNA gene(0.60%). Minimum-spanning network displayed several haplotypes that are unique to each species, suggesting a higher degree of subdivision between both species. As for prevalence surveillance, both adult and subadult rats were susceptible to the infection, in which males were the most susceptible. Kidney was notable as the favourable organ for colonisation of leptospires. Rats captured from fresh markets were highly infected with Leptospira spp.(54.28%) compared to those from housing areas(26.47%).Conclusions: Rattus rattus represents an important asymptomatic transmitter of pathogenic leptospires, and hence is of public health concerns.     

Effect of protein intake on regional vascular resistance and reactivity to angiotensin II in the rat

Male Sprague-Dawley rats (200-250 g) were fed low protein (6%) diets (LP rats), high protein (50%) diets (HP rats), or regular rat chow (approximately 16% protein) (control rats) and studied under anesthesia after 2 weeks. Dietary protein intake did not affect mean arterial pressure, but renal blood flow was increased in the HP rats and decreased in the LP rats compared with the control rats. Mesenteric blood flow was not significantly different in the three diet groups. Captopril (10 mg.kg-1 i.v.) had no effect on renal vascular resistance in the HP rat but did reduce the elevated renal vascular resistance seen in the LP rat. Meclofenamate (5 mg.kg-1 i.v.) did not significantly affect renal hemodynamics in either HP or LP rats. Finally, the HP rat exhibited resistance to the systemic pressor, renal, and mesenteric vasoconstrictor effects of angiotensin II. Captopril restored the systemic pressor and the mesenteric vasoconstrictor response but not the renal vasoconstrictor response to angiotensin II. Meclofenamate, on the other hand, restored both the systemic pressor response and the renal vasoconstrictor response. Thus, in the LP rat, the vascular response to angiotensin II remains intact, and renal vasoconstriction appears to be mediated by angiotensin II. In contrast, in the HP rat, the renovascular response to angiotensin II is blunted apparently because of enhanced renal prostaglandin production. However, neither increased renal prostaglandin synthesis nor blunting of the renovascular response to angiotensin II appears to account for the chronic vasodilation seen in the HP rat.     

问号赖型钩端螺旋体重组质粒pDL121的初步研究

目的　探讨问号赖型钩端螺旋体抗原基因的特点。方法　应用６ 种常见内切酶（ＢａｍＨＩ,Ｂｇｌ Ⅱ,ＥｃｏＲⅠ,Ｈｉｎｄ Ⅲ,ＰｓｔⅠ,Ｐｖｕ Ⅱ）对从问号赖型钩端螺旋体０１７ 株的基因文库中筛选出来的重组质粒ｐＤＬ１２１ 外源基因进行酶谱分析,同时用Ｄｉｇｏｘｉｎ 标记的ｐＤＬ１２１ 外源基因片段作探针对不同种属的致病性钩端螺旋体和非致病性钩端螺旋体基因进行杂交分析。结果　显示问号赖型钩端螺旋体重组质粒ｐＤＬ１２１ 外源基因没有６ 种内切酶的酶切位点,重组探针与致病性钩体（ｓｅｒｏｖａｒｌａｉｓｔｒａｉｎ０１７,ｓｅｒｏｖａｒ ｈｅｂｄｏｍａｄｉｓｓｔｒａｉｎ ５６６１０ ,ｓｅｒｏｖａｒ ｐｏｍｏｎａｓｔｒａｉｎ ５６６０８）有杂交信号,与非致病性钩体（ｓｅｒｏｖａｒ ｐａｔｏｃ ｓｔｒａｉｎ Ｐａｔｏｃ Ⅰ,ｓｅｒｏｖａｒｉｌｌｉｎｉｓｔｒａｉｎ ３０５５）无杂交信号,亦不识别大肠杆菌。结论　重组质粒ｐＤＬ１２１ 外源基因可能是问号赖型钩端螺旋体的一个新基因,进一步测序分析将揭示该基因本质,同时因该重组探针能鉴别致病性钩体和非致病性钩体,提示其可用于钩端螺旋体病的早期诊断及钩端螺旋体的鉴定和分类。     

Effects of early carvedilol treatment and withdrawal on the development of hypertension and renal vascular narrowing

BACKGROUND: The aims of this study were to examine whether combined blockade of alpha(1) and beta-adrenoceptors with carvedilol postweaning affected the development of hypertension and renal vascular narrowing in spontaneously hypertensive rats (SHR), and whether these effects on pressure and renal vascular changes persisted after treatment withdrawal. METHODS: From 4 to 12 weeks of age male SHR were administered carvedilol in rat chow at 1.2 mg/g chow (low-dose) or 2.4 mg/g chow (high-dose), or were given normal chow. At 12 weeks of age, rats from each group either underwent experimentation or had treatment withdrawn and were studied at 20 weeks. On the experimental day, conscious mean arterial pressure (MAP) was measured and, as a functional test of renal vessel lumen characteristics, pressure-flow and pressure-glomerular filtration rate (pressure-GFR) relationships were determined in the maximally dilated kidney. RESULTS: At 12 weeks of age, SHR on low and high-dose carvedilol had significantly lower MAP than that of untreated SHR (137 +/- 3, 134 +/- 1, 152 +/- 2 mm Hg, respectively; P <.001). The SHR treated with high-dose (but not low-dose) carvedilol demonstrated a steeper renal pressure-flow relationship (P <.001), and a leftward shifted (P <.01) and steeper (P <.001) pressure-GFR relationship compared with control SHR. Eight weeks after carvedilol withdrawal, there were no significant differences in MAP, pressure-flow, or pressure-GFR relationships between groups. CONCLUSIONS: These results suggest that postweaning alpha(1) and beta-adrenoceptor blockade with high-dose carvedilol attenuated the development of hypertension and led to a preferential reduction in preglomerular resistance (increased lumen dimensions) independent of the effects on MAP. However, treatment of SHR from 4 to 12 weeks of age with high-dose carvedilol did not lead to persistent, long-term effects on arterial pressure or renal vascular narrowing after treatment withdrawal.     

Immune responses to Leptospira infection: roles as biomarkers for disease severity

Various leptospiral components have been identified and shown to be involved in tissue destruction. In addition, immune responses to leptospires have been implicated in target organ damages in severe leptospirosis cases. Several inflammatory mediators were shown to be higher in susceptible animals than in resistant hosts. Moreover, cytokines/chemokines and serum proteins induced following Leptospira infection were suggested to be biomarkers for disease severity in human leptospirosis. This review focuses on the role of immune responses in the severity of leptospirosis. Studies in both animal models and humans are discussed.     

Glycoproteins from Leptospira interrogans serogroup icterohaemorrhagiae: distribution in the liver and kidney of experimentally infected guinea pigs

Tissue damage in leptospirosis has been ascribed to direct effect of the microorganisms and/or their virulence, including products synthetized by leptospires or released during their lysis. This study aimed at chemical extraction of the glycolipoprotein (GLP) from virulent leptospires, production of a rabbit anti-GLP and analysis of its distribution in liver and kidney of inoculated guinea-pigs, sacrificed sequentially from the 1st to 6th day of infection, covering the whole, spectrum of acute leptospirosis. The comparison of GLP expression to local injuries aimed at new pathogenetic data. GLP was detected in liver and kidney in 2 out of 6 guinea-pigs on the 5th day and in all 6 animals on the 6th day of infection. Granular forms were seen in the cytoplasm of macrophages, free in interstitium or adhered to endothelial and parenchymal cell membranes, especially in the most damaged sites. These findings lead us to the hypothesis of GLP as a toxic factor resulting from leptospiral lysis by macrophages. Although it was not proved as a promoter of initial lesions, it seems to be related to the enhancement of tissue damage late in the course of the disease.     

Resistance to mineralocorticoid-induced hypertensive vascular disease

To support our contention that the Wistar-Furth rat is resistant to mineralocorticoid hypertension, we assessed the effects of deoxycorticosterone (DOC) administration or renal artery stenosis on the development of hypertension in the Sprague-Dawley and Wistar-Furth rat strains. Weekly administration of mineralocorticoid in the form of DOC pivalate resulted in rapid, severe hypertensive cardiovascular disease in Sprague-Dawley rats. Within 5 weeks the mean conscious systolic blood pressures in steroid-treated and control rats were 186 +/- 4 and 118 +/- 5 mm Hg, respectively. In contrast, blood pressures of Wistar-Furth rats were only moderately elevated, even after 10 weeks of DOC pivalate administration (136 +/- 2 vs 116 +/- 2 mm Hg for controls). Furthermore, none of the steroid-treated Wistar-Furth animals exhibited cardiovascular lesions. In parallel studies, littermates of these rat strains were subjected to renal artery stenosis and blood pressures were determined weekly in conscious rats. Silver clip constriction of the left renal artery, in the presence of the contralateral kidney, resulted in a rapid, sustained elevation of blood pressure in both Sprague-Dawley and Wistar-Furth rat strains (177 +/- 4 and 176 +/- 5 mm Hg, respectively). Corticosteroid levels were also determined in DOC-treated Sprague-Dawley and Wistar-Furth rats. The regimen employed resulted in a 10-fold increase in DOC levels as compared with controls, and the levels achieved were comparable in both strains. Thus, the Wistar-Furth rat appears to be selectively resistant to mineralocorticoid hypertensive vascular disease and thus affords a model for studying mechanisms of steroid hypertension.     

Experimental chronic Lyme borreliosis in Lewis rats

The course of Lyme borreliosis in LEW/N rats inoculated intraperitoneally as infants with 10(6) Borrelia burgdorferi was followed for 360 days. Spirochetes were detected in the blood through 30 days, in the brain through 60 days, and persisted in the spleen, liver, kidneys and articular tissue through 360 days. Acute exudative arthritis, tendonitis, and bursitis were evident in multiple joints by day 30. Arthritis regressed thereafter but capsular fibrosis and lymphoplasmacytic infiltrates persisted throughout the study. Several rats developed exacerbations of acute arthritis within days 180-360, a pattern similar to that encountered in human Lyme disease. Rats had a high prevalence of nonsuppurative myocarditis and vasculitis during days 90-360. Spirochetes were visualized by microscopy in joints and other tissues during the first month of infection, but were seen only sporadically thereafter. All rats seroconverted to B. burgdorferi by day 30. IgM titers persisted and IgG titers rose progressively through day 360. Immunoblots revealed IgM reactivity to a single 41 kDa protein until 360 days, when reactivity to a 60 kDa protein emerged. IgG reactivity occurred against progressively more proteins with time, indicating continued antigenic stimulation. Chronic and recurrent arthritic lesions and myocardial involvement suggest that the rat is a reliable model for further investigation.     

细菌潜生体相关的IBS大鼠模型建立的影响因素

目的研究细菌潜生体（CGC）相关的IBS大鼠模型建立的影响因素，以完善该模型的建立。方法采用二步刺激法建立IBS大鼠模型，先用不同浓度组的头孢呋辛钠刺激大鼠产生CGC，然后用辣椒液刺激。模型建成判定指标为CGC定植、粪便含水量和排便次数等。结果不同浓度组的头孢吠辛钠刺激大鼠，引起CGC的动态变化特点和定植率不一样。获得IBS大鼠雄性与雌性比例为1．5：1。结论CGC相关的IBS大鼠模型建立，头孢呋辛钠浓度组合对CGC动态变化特点和定植起关键作用，并且该动物模型建立有性别差异，对IBS的发病机制与性别差异研究有重要意义。     

Laboratory and clinical features of experimental feline leptospirosis

In order to assess the clinical, laboratorial and epidemiological aspects of feline leptospirosis, ten female and male adult cats were experimentally inoculated with pathogenic and autochthonous field isolate of Leptospira interrogans. Five of them were inoculated subcutaneously with serovar icterohaemorrhagiae (R-192) and the others five with serovar canicola. No clinical and laboratorial alterations were found in these animals. Antileptospiral agglutinins were detected in 90% of the infected cats, shortly after the 1st week after inoculation. The leptospiral agglutinins were detected for 8 to 12 weeks and the elimination of leptospires through urine was observed only in animals infected with serovar canicola, beginning 2 to 4 weeks after inoculation and lasting for 2 to 8 weeks. Isolations of leptospires from blood and kidneys were unsuccessful.     

Phosphodiesterase 5 inhibitors attenuate renal tubular apoptosis after partial unilateral ureteral obstruction: an experimental study

The aim of the present study was to evaluate the effects of phosphodiesterase 5 inhibitors on renal tubular apoptosis and also on expressions of endothelial and inducible nitric oxide synthases (eNOS and iNOS) in the ipsilateral kidney after partial unilateral ureteral obstruction (PUUO) in a rat model. Forty Wistar albino rats were divided into five groups. In Groups 1-4, left experimental PUUO was created. Sildenafil, vardenafil, and tadalafil were administrated to the rats of Groups 2-4, respectively. The pills were orally given to the rats for 30 days. Group 5 was defined as sham. After 30 days, all rats were sacrificed, and nephrectomy was performed. The renal specimens were examined histopathologically. Left hydroureteronephrosis was observed in Groups 1-4. Mean apoptotic cell count and eNOS and iNOS levels were significantly increased in Group 1 when compared with the other groups. The rats in Groups 2-4 showed significantly decreased apoptotic cell count and eNOS and iNOS values in the renal tubular tissue in accordance with Group 1 (p<0.05). There were significant differences in apoptotic cell counts between sildenafil group and the other two study groups. The sildenafil group demonstrated lesser apoptotic cell count than the vardenafil (p=0.021) and tadalafil (p=0.009) groups. PUUO increases the renal tubular apoptosis and elevates NOS concentrations in renal tubular tissue after PUUO. Phosphodiesterase 5 inhibitors have a protective effect against the tubular apoptosis.