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A mouse model of salpingitis and subsequent tubal infertility induced by a human strain of Chlamydia trachomatis has been studied. C3H/He female mice were inoculated into the ovarian bursa. Some of the mice (six infected, five controls) were killed on days 15 and 23 and the remaining animals (10 infected, 10 controls) were mated on day 15. On day 15, the infection was maximal with intratubal inflammation, elevated antichlamydial antibody titre and positive cultures in 12 cases out of 16. After 19 weeks of housing with the male, the proportion of fertilized females was significantly lower in the infected group (20% versus 100% in the control group P less than 0.01). In the killed mice, hydrosalpinx and or tubal occlusion were noted at this time in nine cases out of 10, despite an apparent bacteriological healing. [ABSTRACT FROM AUTHOR]

The influence of the pre-treatment duration of infection on the efficacies of three different antibiotic regimens was investigated in a rabbit model of subacute endocarditis caused by a novel, nutritionally-variant species, strain GaD. Treatment was initiated either 6 or 10 days after bacterial inoculation (days 7 and 11 respectively) and comprised procaine penicillin (150,000 IU/kg bd), alone or combined with tobramycin (12 mg/kg od), teicoplanin (10 mg/kg bd), all administered by the intramuscular route for 4 days. The MICs and MBCs of penicillin, tobramycin and teicoplanin were 0·015 and 1 mg/L, 8 and 16 mg/L and 0· and 256 mg/L respectively. In the control rabbits, the mean (±S.D.) weights of the vegetations were 25±16 mg on day 7 and 45±34 mg on day 11 (=0·06). The mean (±S.D.) reductions in the number of cfu in the vegetations of the treated groups of animals after completion of therapy which had been started on days 7 and 11, compared with the mean numbers of cfu in the vegetations of the untreated controls on days 7 and 11 (Δlog cfu/g) were 4·0±1·3 and 2·1±1·5 respectively for penicillin (<0·05), 3·2±1·8 and 2·4±1·8 respectively for teicoplanin and 5·4±1·2 and 5·2±1· respectively for the combination of penicillin and tobramycin. The increase in the size of the vegetations and changes in the metabolism of the bacteria within the vegetations between days 7 and 11, as demonstrated by electron microscopy, might explain why penicillin was more effective earlier in the course of the disease and why the influence of the duration of infection before treatment was initiated, varied according to the antibiotic regimen. These results suggest that the use of bactericidal regimens, such as the combination of penicillin and tobramycin, which are equally effective in reducing the bacterial counts in vegetations which have been infected for both long and short periods could minimize the risk of relapse in patients with endocarditis in whom there have been long delays before initiating treatment and/or who have large vegetations. [ABSTRACT FROM PUBLISHER]

Background: Extensive spread of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in the United States, and the concomitant increase in severe invasive staphylococcal infections, including osteomyelitis, in healthy children, has led to renewed interest in Panton-Valentine leukocidin (PVL). However, the pathogenetic role of PVL in staphylococcal infections remains controversial, possibly because it depends on the site of infection., Methodology/principal Findings: We compared the course of experimental rabbit osteomyelitis due to the PVL-positive CA-MRSA strain USA 300 (LAC) and its PVL-negative isogenic derivative (LACDeltapvl), using a low and a high inoculum (8x10(5) and 4x10(8) CFU). With the low inoculum, bone infection was less frequent on day 7 (D7) and day 28 (D28) with LACDeltapvl than with LAC (respectively 12/19 and 18/19 animals, p = 0.042). With the high inoculum of both strains, all the animals were infected on D7 and the infection persisted on D28 in almost every case. However, tibial bacterial counts and the serum CRP concentration fell significantly between D7 and D28 with LACDeltapvl but not with LAC. Respectively 67% and 60% of LAC-infected rabbits had bone deformation and muscle/joint involvement on D7, compared to 0% and 7% of LACDeltapvl-infected rabbits (p = 0.001 and p = 0.005 respectively). Between D0 and D28, the anti-PVL antibody titer increased significantly only with the high inoculum of LAC., Conclusions/significance: PVL appears to play a role in the persistence and rapid local extension of rabbit osteomyelitis, in keeping with the greater severity of human bone infections due to PVL-positive S. aureus. The possible therapeutic implications of these findings are discussed.

The role of the renin-angiotensin system has been investigated by overexpression or inactivation of its different genes in animals. However, there is no data concerning the effect of the constitutive activation of any component of the system. A knockin mouse model has been constructed with a gain-of-function mutant of the Ang II receptor, type 1A (AT(1A)), associating a constitutively activating mutation (N111S) with a C-terminal deletion, which impairs receptor internalization and desensitization. In vivo consequences of this mutant receptor expression in homozygous mice recapitulate its in vitro characteristics: the pressor response is more sensitive to Ang II and longer lasting. These mice present with a moderate (~20 mmHg) and stable increase in BP. They also develop early and progressive renal fibrosis and cardiac fibrosis and diastolic dysfunction. However, there was no overt cardiac hypertrophy. The hormonal parameters (low-renin and inappropriately normal aldosterone productions) mimic those of low-renin human hypertension. This new model reveals that a constitutive activation of AT(1A) leads to cardiac and renal fibrosis in spite of a modest effect on BP and will be useful for investigating the role of Ang II in target organs in a model similar to some forms of human hypertension.

Galectin 3 belongs to a family of glycoconjugate-binding proteins that participate in cellular homeostasis by modulating cell growth, adhesion, and signaling. We studied adult galectin 3 null mutant (Gal 3-/-) and wild-type (WT) mice to gain insights into the role of galectin 3 in the kidney. By immunofluorescence, galectin 3 was found in collecting duct (CD) principal and intercalated cells in some regions of the kidney, as well as in the thick ascending limbs at lower levels. Compared to WT mice, Gal 3-/- mice had approximately 11% fewer glomeruli (p < 0.04), associated with kidney hypertrophy (p < 0.006). In clearance experiments, urinary chloride excretion was found to be higher in Gal 3-/- than in WT mice (p < 0.04), but there was no difference in urinary bicarbonate excretion, in glomerular filtration, or urinary flow rates. Under chronic low sodium diet, Gal 3-/- mice had lower extracellular fluid (ECF) volume than WT mice (p < 0.05). Plasma aldosterone concentration was higher in Gal 3-/- than in WT mice (p < 0.04), which probably caused the observed increase in alpha-epithelial sodium channel (alpha-ENaC) protein abundance in the mutant mice (p < 0.001). Chronic high sodium diet resulted paradoxically in lower blood pressure (p < 0.01) in Gal 3-/- than in WT. We conclude that Gal 3-/- mice have mild renal chloride loss, which causes chronic ECF volume contraction and reduced blood pressure levels.

The enzyme 11-beta hydroxysteroid dehydrogenase type 2 plays a major role in blood pressure regulation. It metabolizes glucocorticoid hormones into derivatives with low affinity for the mineralocorticoid receptor, preventing its permanent occupancy by circulating cortisol, which is 100- to 1000-fold more abundant than aldosterone in the plasma. Inactivating mutations of the enzyme result in severe hypertension, as seen in children with apparent mineralocorticoid excess syndrome. In patients with essential hypertension, however, attempts to evidence enzyme deficiency have been inconclusive. In this pilot study, its catalytic activity was measured directly in aldosterone-sensitive sweat gland ducts collected from skin biopsy samples of 10 male normotensive subjects and 10 subjects with essential hypertension (more than 140 to 90 mm Hg) with no sign of hypermineralocorticism. Isolated ducts were assayed for nicotinamide-dinucleotide-dependent dehydrogenase activity (transformation of tritiated corticosterone into tritiated-11 dehydrocorticosterone, as measured by high-pressure liquid chromatography). Hypertensive patients exhibited significantly lower 11-beta hydroxysteroid dehydrogenase type 2 activity (9.7+/-4.7 femtomoles per 3 mm length of duct and per 10 minutes incubation, median+/-SD) than did normotensive subjects (15.9+/-2.6). Such defect was undetectable using the classical urinary corticosteroid metabolism indexes, probably because of compensatory mechanisms. Relations between these findings and blood pressure levels should benefit from direct enzyme measurements in the vasculature. In conclusion, this cross-sectional study points to partial 11-beta hydroxysteroid dehydrogenase type 2 deficiency as a novel feature of essential hypertension, which should stimulate search for new signaling pathways and therapeutical targets.

The human mineralocorticoid receptor (hMR), a ligand-dependent transcription factor (NR3C2) which belongs to the nuclear receptor superfamily, mediates most of the known effects of aldosterone. Beside its involvement in the regulation of sodium balance and the control of blood pressure, aldosterone-hMR tandem also exerts important regulatory functions on the cardiovascular and central nervous systems. To study the molecular mechanisms involved in the tissue-specific expression of hMR and explore its functional implication in pathophysiology, transgenic mouse models have been generated using both targeted oncogenesis and MR overexpression. We have previously demonstrated that the transcription of hMR is directed by two alternative promoters, P1 and P2, which correspond to the 5'-flanking regions of the untranslated exons 1alpha and 1beta of the hMR gene, respectively. Utilization of P1 and P2 to drive expression of the SV40 large T antigen (TAg) in transgenic mice led us (i) to determine distinct tissue-specific patterns of promoter usage; (ii) to identify novel sites of MR expression including brown adipose tissue, thus providing a new functional link between aldosterone and energy homeostasis; (iii) to generate original immortalized cell lines derived from numerous aldosterone-sensitive tissues most notably distal nephron, brown fat, skin, liver, lung, brain, heart, blood vessels and inner ear. These differentiated cell lines represent suitable models to further explore cell-specific mineralocorticoid responses and cross-talk with other signaling pathways. Generation of transgenic mice in which hMR expression was directed by P1 promoter demonstrated the importance of MR in the cardiac and renal function. Morphological and functional alterations of the renal tubule were observed with basal decreased sodium/potassium ratio exacerbated under sodium depletion. Hypokinetic dilated cardiomyopathies were associated with tachycardia, arrhythmia but normal arterial blood pressure emphasizing the direct role of MR on cardiomyocyte function. Taken together, transgenic animal models constitute valuable experimental systems to gain new insights into the widespread and pleiotropic in vivo functions of MR.

The mineralocorticoid receptor (MR), a ligand-dependent transcription factor, mediates aldosterone actions in a large variety of tissues. To explore the functional implication of MR in pathophysiology, transgenic mouse models were generated using the proximal human MR (hMR) promoter to drive expression of hMR in aldosterone target tissues. Tissue-specific analysis of transgene expression in two independent transgenic animal (TG) lines by ribonuclease protection assays revealed that hMR is expressed in all mineralocorticoid-sensitive tissues, most notably in the kidney and the heart. TG exhibit both renal and cardiac abnormalities. Enlarged kidneys were histologically associated with renal tubular dilation and cellular vacuolization whose prevalence increased with aging. Renal clearance studies also disclosed a significant decrease in urinary potassium excretion rate in TG. hMR-expressing animals had normal blood pressure but developed mild dilated cardiomyopathy (increased left ventricle diameters and decreased shortening fraction), which was accompanied by a significant increase in heart rate. Differential gene expression analysis revealed a 2- to 5-fold increase in cardiac expression of atrial natriuretic peptide, serum- and glucocorticoid-induced kinase, and early growth response gene 1 as detected by microarrays; renal serum- and glucocorticoid-induced kinase was also induced significantly. Altogether, TG exhibited specific alteration of renal and cardiac functions, thus providing useful pathophysiological models to gain new insights into the tissue-specific mineralocorticoid signaling pathways.

To investigate the temporal relationship between CD8+ lymphocyte phenotypic alterations, the CD4+ T cell decline, and plasma HIV RNA levels during the natural history of HIV infection, 33 treatment-naive HIV-infected patients with > or =400 CD4+ cells/microl were studied prospectively for 3 years. During the study period, 20 patients remained untreated, and only 6 received more than 6 months of therapy. A significant relationship was found between changes in plasma HIV RNA and changes in the proportion of CD38+CD8+ cells. Conversely, the number of CD4+ T cells lost per year was strongly related to the increase in the proportion of CD28-CD8+ T cells. A strong relationship between mean yearly changes in CD4+ T cell numbers and changes in HIV RNA was also observed. CD4+ T cell changes were associated with changes in both viral load and CD8+ T cell activation. These results provide support for the use of both virologic and immunologic parameters for prognosis and management during HIV infection.

Aggravation of necrotizing fasciitis (NF) by the administration of non-steroidal antiinflammatory drugs (NSAIDs) has recently been suggested. A rabbit model of streptococcal NF was used to study the effects of parenteral administration of an NSAID on NF evolution and outcome. Of 16 rabbits inoculated with a Streptococcus pyogenes suspension together with staphylococcal alpha toxin, 8 were treated with two doses of 4 mg/kg diclofenac on day 1 after inoculation. Clinical, bacteriological and histological studies were performed until day 10. Under our experimental conditions, NSAID treatment significantly limited NF extension. A specific inverse relationship between the extent of inflammation and bacterial density in NF lesions was observed on day 1 after inoculation in the treated group suggesting that the greater severity of NF in humans treated with an NSAID could be due to the therapeutic delay induced by the misleading clinical effects of the NSAID, and not to inhibition of antibacterial defence.

Objective: To analyse the relationship between CD8+ lymphocyte phenotype alterations and plasma HIV RNA levels in HIV-infected patients treated with the zidovudine-didanosine combination., Methods: A total of 30 HIV-infected patients who had never received antiretroviral therapy and who were starting treatment with a combination of zidovudine and didanosine were prospectively studied. Multiparameter flow cytometric analysis of CD8+ lymphocytes and plasma HIV RNA determination were performed on day 0, day 15 and monthly from months 1 to 6., Results: Patients were divided into three categories according to the time-course of plasma HIV RNA levels. In 14 patients, an early and sustained fall in plasma HIV RNA to below the detection limit (500 copies/ml) was observed; in 10 patients, the fall was transient; in six patients, plasma HIV RNA was always detectable (non-responders). The mean CD4+ lymphocyte gain was 120 x 10(6)/l at month 6 in sustained and transient responders, and 55 x 10(6)/l in non-responders. A significant fall in the proportion of CD8+ lymphocytes with an activated phenotype was observed only in the two groups of responders, and was higher in the sustained responders (CD38+HLA-DR+, -56.8%; CD38+CD45RO+, -54.0%; HLA-DR+CD45RO+, -48.4%; CD38+CD28-, -47.3%)., Conclusion: A fall in the proportion of activated CD8+ lymphocytes is associated with the disappearance of HIV RNA from plasma during antiretroviral therapy. Undetectable plasma HIV RNA is not associated with a return to normal CD8+ lymphocyte activation status after 6 months of treatment, suggesting that viral replication persists in lymphoid tissues.

We looked for associations between pharmacokinetic (Pk) and pharmacodynamic (Pd) parameters of ciprofloxacin (CPFX) and sparfloxacin (SPFX) and the in vivo efficacy of these antimicrobials in an immunocompetent mouse model of severe Streptococcus pneumoniae pneumonia. Bacterial killing curves recorded in the lungs during the 24 h after single subcutaneous injections of the fluoroquinolones (FQs) in doses ranging from 6.25 to 200 mg/kg were compared with mean Pk/Pd parameters in the serum of the same mice. The impact of the dosing interval on the antimicrobial dose response was evaluated based on the survival of mice treated for 3 days with CPFX (25-200 mg/kg) or SPFX (6.25-50 mg/kg) administered at various intervals from 3 to 24 h. Bacterial killing curves showed that the maximal bacterial decrease achieved in the lungs was correlated, similarly for both FQs, with the area under the curve (AUC) above the minimal inhibitory concentration (MIC) (overall correlation: r = 0.968, P < 10(-4)). CPX attained higher maximal bactericidal effect values, a steeper killing slope and a shorter time to maximal bactericidal effect in comparison with SPX for the highest doses tested. The lower MIC of SPFX compared with CPFX (0.25 vs. 0.75 microgram/ml) and its higher AUC/dose ratio (resulting from a lower serum peak but a longer half-life) translated into a greater area under the bactericidal curve. In the dose fractionation experiments, the Pk/Pd parameter most closely correlated with the survival rate for both FQs was the daily AUC/MIC ratio (r = 0.976, P < 10(-4)). When the AUC/MIC ratio was greater than 160, the probability of a clinical cure was 100%, independently of the dosage schedule.

The increasing emergence of penicillin-resistant and multidrug-resistant strains of Streptococcus pneumoniae will create a serious therapeutic problem in coming years. Trovafloxacin is a novel naphthyridone quinolone with promising activity against S. pneumoniae, including penicillin-resistant strains (MIC for 90% of the isolates tested, 0.25 microg/ml). We compared its in vivo efficacy with that of other fluoroquinolones (ciprofloxacin, temafloxacin, and sparfloxacin) and a reference beta-lactam (amoxicillin) in a model of acute experimental pneumonia. Immunocompetent Swiss mice were infected by peroral tracheal delivery of a virulent, penicillin-susceptible strain (MIC, 0.03 microg/ml); leukopenic Swiss mice were infected with three poorly virulent, penicillin-resistant strains (MICs, 4 to 8 microg/ml) and a ciprofloxacin-resistant strain (MIC, 32 microg/ml). Treatments were started 6 h (immunocompetent mice) or 3 h (leukopenic mice) after infection. Doses ranging from 12.5 to 300 mg/kg were given at 12- or 8-h intervals for 3 days. Trovafloxacin (25 mg/kg) was the most effective agent in vivo against penicillin-susceptible and -resistant strains. Corresponding survival rates were 2- to 4-fold higher than with 50-mg/kg sparfloxacin or temafloxacin and 8- to 16-fold higher than with 100-mg/kg ciprofloxacin. The ratios of the area under the concentration-time curve to the MIC in serum and lung tissue were more favorable with trovafloxacin than with the other quinolones. Efficacy in vivo correlated with pharmacokinetic parameters. Trovafloxacin shows potential for the treatment of infections due to penicillin-susceptible and -resistant S. pneumoniae but appears to be ineffective against a ciprofloxacin-resistant strain.

The middle ear mucosa is described as a non-specialized site where drug substances diffuse passively. However, precise pharmacokinetic studies on antibiotic penetration into middle ear effusion (MEE) are difficult to conduct in humans because of ethical and methodological problems: (1) studies must involve the population in which acute otitis media (AOM) is most frequent (i.e. in children from 3 months to 3 years of age); (2) studies are commonly performed during surgery for chronic otitis media with effusion, whereas drug penetration into MEE is higher during AOM; (3) kinetics are deduced from data per individual obtained in groups with marked interindividual variations. Furthermore, the results of different studies are difficult to compare because of differences in protocols, antibiotic assay methods and interpretation. Clinical studies have nonetheless shown the poorly predictive nature of serum concentrations, given the large differences in drug delivery to the MEE among antibiotic classes, among members of the same class, and among individuals receiving a given antibiotic. Experimental studies can help to narrow the gap between in vitro and clinical data, as the more precise pharmacokinetic data they yield can throw light on the link between drug/host/pathogen factors and bacteriologic efficacy.

Objective: Study and development of a gerbil model of pneumococcal meningoencephalitis secondary to acute middle ear (ME) otitis. Preliminary data raised the hypothesis of a direct bacterial dissemination from the ME focus to the central nervous system. This infection pattern was examined., Design: Animals were inoculated bilaterally by transbulla challenge with a serotype 3 strain of Streptococcus pneumoniae at various inoculum sizes. The incidence and course of meningeal complications were studied in relation to the course of ME otitis., Results: After inoculation of 40 bacteria per ear, lethal meningeal complications occurred in 14 (29%) of 48 cases. A 76% rate (25 of 33 animals) of early meningeal involvement was observed after inoculation of 10(4) bacteria per ear. Actual involvement of brain was confirmed histologically for both infection schemes. Bacterial counts 20 to 22 hours after infection with the higher inoculum showed various phases of the extension of the ME infection to brain tissue, cerebrospinal fluid, and bloodstream. Bacterial counts in ME and brain tissue were strongly correlated (P < .001). Nine of the 25 animals with infection of the central nervous system had positive brain tissue cultures without bacteremia., Conclusion: Gradations in inflammatory aspects of the meninges and cerebral parenchyma, together with bacteriologic findings, indicate a primary invasion of meningeal spaces that can result in lethal encephalitis and septicemia. This model might be useful for preclinical therapeutic assays on pneumococcal meningeal complications, including infections due to strains with abnormal susceptibility to antibiotics.

Intrauterine growth retardation (IUGR) was induced in Sprague-Dawley rats by partial artery ligation of one uterine horn in the mother on day 17 of gestation or by feeding the mother a 5% protein diet from day 8 of gestation. The controls were pups of the contralateral uterine horn or pups born to mothers fed a normal (22%) protein diet. The number of nephrons present at birth and the final number of nephrons in 2-week-old rats were counted throughout the entire kidney. The number of nephrons present at birth and the final number of nephrons were significantly correlated with birth weight for growth-retarded rats of both groups and their corresponding controls (P < 0.02 for the poorest correlation). Clearance experiments and morphometric studies of 2-week-old rats born to mothers with uterine artery ligation indicated that, despite a large compensatory hypertrophy of the nephrons in those animals born with a nephron deficit of about 30%, the overall renal function was impaired. We conclude that IUGR is accompanied by a nephron deficit which may not be fully compensated for within the first weeks after birth.

We conducted a retrospective study of 29 consecutive cases of temporal arteritis, all with definite histological diagnostic criteria. The epidemiological aspects of the main clinical and biological features were compared according to their mode of recruitment, the patients being hospitalized either in an ophthalmological unit (n = 15), or in an Internal Medicine unit (n = 14). The level of fever and of sedimentation rate were significantly less in the ophthalmological group (respectively p < 0.001 and p < 0.02), a third of which is represented by the purely ophthalmological manifestation called "occult temporal arteritis". Among the ophthalmological manifestations, despite the fact that the recruitment bias prevented any strict epidemiological comparison, we were surprised to find no significant difference between the two groups concerning the frequency of transient ophthalmological manifestations, which confirmed in half the patients their reputation of forerunners of irreversible lesions. Thus, the presentation of temporal arteritis differs according to its ophthalmological or Internal Medicine recruitment. We were unable to determine a precise chronology difference in the principal manifestations between these two groups. The severity of the ocular manifestations justifies looking for temporal arteritis in all cases of transient ophthalmological manifestations, even if clinically totally isolated.