Molecular characterization,serotyping, and antibiotic susceptibility profile of Leptospira interrogans serovar Copenhageni isolates from Brazil

Leptospira interrogans serogroup Icterohaemorrhagiae is the major serogroup infecting humans worldwide, and rodents and dogs are the most significant transmission sources in urban environments. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the epidemiology of leptospirosis. In this study, 20 Leptospira isolates were evaluated by pulsed-field gel electrophoresis (PFGE), variable number tandem-repeat analysis (VNTR), serotyping, and determination of antimicrobial resistance profile. Isolates, originated from bovine, canine, human, and rodent sources, were characterized by microscopic agglutination test with polyclonal and monoclonal antibodies and were identified as L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni. MICs of antimicrobials often used in veterinary medicine were determined by broth microdilution test. Most of tested antibiotics were effective against isolates, including penicillin, ampicillin, and ceftiofur. Higher MIC variability was observed for fluoroquinolones and neomycin; all isolates were resistant to trimethoprim/sulfamethoxazole and sulphadimethoxine. Isolates were genotyped by PFGE and VNTR; both techniques were unable to discriminate between serovars Copenhageni and Icterohaemorrhagiae, as expected. PFGE clustered all isolates in 1 pulsotype, indicating that these serovars can be transmitted between species and that bovine, rodent, and dogs can maintain them in the environment endangering the human population.     

The risk of cardiovascular disease associated with proteinuria in renal transplant patients

Proteinuria in the general population has been shown to be associated with cardiovascular disease, which is the main cause of death in renal transplantation. We investigated the effect of proteinuria on cardiovascular disease after renal transplantation in 532 renal transplant patients with functioning grafts for more than 1 year. Patients were classified into two groups depending on the presence of persistent proteinuria. We analyzed graft and patient survival, posttransplantation cardiovascular disease, and main causes of graft loss and death. Five- and 10-year graft and patient survival rates were lower in the group with proteinuria. The main cause of death was vascular disease in both groups. The presence of posttransplantation cardiovascular disease was higher in the group with proteinuria. Persistent proteinuria was associated with graft loss (RR=4.18), patient death (RR=1.92), and cardiovascular disease (RR=2.45). In conclusion, persistent proteinuria was an independent risk factor for increased cardiovascular morbidity and mortality in renal transplant patients.     

Return to dialysis after renal transplantation. Which would be the best way?

The exact moment to return to dialysis when a graft fails has not clearly been established. Furthermore, there is no agreement with respect to whether the guidelines accepted for patients entering dialysis for the first time are adequate for this subgroup of patients with advanced renal failure, due to the special characteristics of these patients, derived from the immunosuppressive medications they are taking among other accompanying factors. We reviewed a group of renal transplant patients who returned to dialysis and compared them with a group of patients entering dialysis for the first time. Patients with chronic renal failure due to graft failure had a poorer renal function at the time entering dialysis and a more profound anemia. Additionally, complications considered such as the number of hospital admissions during the first year after initiation of dialysis were considerably higher in the group of transplanted patients. We advocate for an earlier referral to the dialysis unit, a more aggressive erythropoietin therapy in the phase of advanced renal failure due to chronic allograft nephropathy, and in selected cases retransplantation before definitive graft loss.     

Acute rejection in the elderly recipient: Influence of age in the outcome of kidney transplantation

Since the immune response in older recipientsis weaker they should be less likely to rejecta transplanted organ and should need lessaggressive immunosuppressive treatment. Our aimwas to record the incidence and severity ofepisodes of acute rejection (AR), estimate theinfluence of these events on graft survival ofelderly recipients (60) and to comparethese with that in younger ones.We performed 363 kidney transplants between1/94 and 12/98, and recorded clinical andimmunological data, incidence-severity of ARand cause of graft loss. Patients were dividedinto two groups, according to the age attransplantation: A (<60, n = 281/77.4%) and B( 60, n = 82/22.6%). The percentage ofaging recipients and mean age of donors andrecipients increased throughout the period.Although the incidence of ATN was higher in theolder group (29% vs.19%, p < 0.0001) thenumber of graft biopsies was equal in bothgroups. The incidence of AR was similar, 33.4%vs. 26.8%, pNS. The number of AR episodes perpatient was 0.44 and 0.41 respectively. Theseverity of AR was: Banff grade I: A (40.3%)/B (45.7%) pNS; grade II: A (44.1%)/B(48.57) pNS; grade III: A (15.5%)/B (5.7%)pNS. Younger recipients presented a higherlevel of panel-reactive antibodies (PRA) (4.3%vs. 2.07%, p = 0.01). One-year patient survivalwas 96%/91% (p<0.05) and graft survivalwas 81%/78% (pNS) respectively.The age of recipient does not seem to haveinfluenced the incidence-severity of AR or thegraft survival. Thus immunosuppression shouldbe individualised for each patient and shouldnot depend on the age at transplantation.     

Elderly patients on chronic hemodialysis: Effect of the secondary hyperparathyroidism on the hemoglobin level

In patients on chronic hemodialysis (CHD)hyperparathyroidism (HPTH) is associated withanemia and resistance to erythropoietin (EPO). This study included 86 CHD elderly pts (meanage 74.8 y, mean time on CHD = 50.5 mos); theywere divided into two groups: I (n = 31) – PTH> 250 pg/mL and II (n = 55) – PTH < 250 pg/mL.All these patients had been on CHD for> 6 mos. No differences were found betweengroups in respect to age, sex distribution andtime on CHD. The levels of creatinine, BUN, Ca,Al, Fe, albumin and ferritin were similar.Group I had a higher P level (5.4 vs 4.3 mg/dL,p = 0.001) and Ca x P (53.5 vs 43.7, p =0.009). Also the Hct (31 vs 33.5%, p = 0.008)and the Hb (10.4 vs 11.2 g/dL, p = 0.009) values werelower in Group I. The EPO dose (88 vs 85 U/kg/week,p = ns) was similar in the two groups.Our data showed that elderly patients with HPTHhave lower Hct and Hb levels than do youngerpatients on a similar EPO dose. We believethese patients will need a more aggressivetherapy with calcitriol.     

Motor cortical hyperexcitability in idiopathic scoliosis: could focal dystonia be a subclinical etiological factor?

The aetiology of idiopathic scoliosis (IS) remains unknown; however, there is a growing body of evidence suggesting that the spine deformity could be the expression of a subclinical nervous system disorder. A defective sensory input or an anomalous sensorimotor integration may lead to an abnormal postural tone and therefore the development of a spine deformity. Inhibition of the motor cortico-cortical excitability is abnormal in dystonia. Therefore, the study of cortico-cortical inhibition may shed some insight into the dystonia hypothesis regarding the pathophysiology of IS. Paired pulse transcranial magnetic stimulation was used to study cortico-cortical inhibition and facilitation in nine adolescents with IS, five teenagers with congenital scoliosis (CS) and eight healthy age-matched controls. The effect of a previous conditioning stimulus (80% intensity of resting motor threshold) on the amplitude of the motor-evoked potential induced by the test stimulus (120% of resting motor threshold) was examined at various interstimulus intervals (ISIs) in both abductor pollicis brevis muscles. The results of healthy adolescents and those with CS showed a marked inhibitory effect of the conditioning stimulus on the response to the test stimulus at interstimulus intervals shorter than 6 ms. These findings do not differ from those reported for normal adults. However, children with IS revealed an abnormally reduced cortico-cortical inhibition at the short ISIs. Cortico-cortical inhibition was practically normal on the side of the scoliotic convexity while it was significantly reduced on the side of the scoliotic concavity. In conclusion, these findings support the hypothesis that a dystonic dysfunction underlies in IS. Asymmetrical cortical hyperexcitability may play an important role in the pathogenesis of IS and represents an objective neurophysiological finding that could be used clinically.     

Topoisomerase II-�� as a predictive factor of response to therapy with anthracyclines in locally advanced breast cancer

Background

Topoisomerase II-?? is a molecular target of anthracyclines; several studies have suggested that topoisomerase II-?? expression is related to response to anthracycline treatment. The objective of this study was to evaluate if topoisomerase II-?? overexpression predicts response to anthracycline treatment in locally advanced breast cancer patients.

Material and methods

Topoisomerase II-??, HER2, estrogen receptor (ER) and progesterone receptor (PR) expression were evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded breast tumors from 111 patients presenting with locally advanced breast cancer between 1995 and 2002. The prognostic value of these markers was analyzed using a multivariate proportional hazards regression model and an interaction analysis between topoisomerase II-?? status and dose intensity.

Results

Tumors from 40 patients (36%) showed topoisomerase II-?? overexpression, 62 patients (56%) for ER, 39 (35%) for PR and 26 (23%) for HER2. There were no significant correlations between topoisomerase II-?? expression and response to therapy, progression-free survival (PFS) or overall survival (OS). Anthracycline dose intensity had a significant impact on PFS and OS in patients overexpressing topoisomerase II-?? (P = 0.010 and 0.027, respectively). Negative PR (P = 0.041), positive HER2 (P = 0.013) were identified as risk factors in the multivariate model. The multivariate analysis in patients topoisomerase II-?? negative shown no significance (HR = 0.92, IC 95% 0.39-2.15, P = 0.839) while the multivariate analysis in topoisomerase II-?? positive, dose intensity shown to be statistically significant (HR = 2.725, IC 95% 1.07-6.95, P = 0.036).

Conclusions

Our data do not support a correlation between topoisomerase II-?? expression in breast cancer patients and improved clinical benefit with anthracycline therapy. However, they do suggest that tumors overexpressing topoisomerase II-?? may experience better clinical benefit with higher anthracycline dose intensity.     

Long-term oral treatment with BAY 41-2272 ameliorates impaired corpus cavernosum relaxations in a nitric oxide-deficient rat model

Study Type – Therapy (case control)
Level of Evidence 3b What’s known on the subject? and What does the study add? Erectile dysfunction is defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance. Nitric oxide (NO) is the main transmitter released from nitrergic nerves and endothelial cells involved in the erectile erection. NO activates the soluble guanylyl cyclase (sGC) in cavernosal smooth muscle to generate cyclic GMP (cGMP) that in turn promotes relaxation and penile erection. Erectile dysfunction genesis can be attributed to a variety of factors such as stress, ageing, drugs, and certain pathological conditions including arterial hypertension, atherosclerosis, dyslipidemia and diabetes mellitus. Inhibitors of phosphodiesterase‐5 (PDE5) like sildenafil (viagra^TM), vardenafil (levitra^TM) and tadalafil (cialis^TM) remain the main oral therapy for erectile dysfunction. These compounds inhibit the cGMP hydrolysis thereby preserving cGMP thus causing an enhancement of corporeal smooth muscle relaxation. The existence of a new NO‐independent regulatory site on sGC has been described. BAY 41‐2272 is a novel compound that generates significant amounts of cGMP by stimulating the sGC in the absence of NO. Compound BAY 41‐2272 also synergize with endogenous NO producing higher cGMP‐dependent cell responses. Using a model of chronic NO deficiency in rats to produce erectile dysfunction, we show that long‐term oral treatment of with BAY 41‐2272 prevents the erectile dysfunction in the NO‐deficient rats. Therefore, this compound may have great therapeutic potential to erectile dysfunction treatment.

OBJECTIVE

? To investigate the potential beneficial effects of 4‐week oral treatment with 5‐cyclopropyl‐2‐[1‐(2‐fluoro‐benzyl)‐1Hpyrazolo[3,4‐b]pyridin‐3‐yl]‐pyrimidin‐4‐ylamine (BAY 41‐2272), a nitric oxide (NO)‐independent soluble guanylate cyclase activator, on impaired rat corpus cavernosum relaxations in NO‐deficient rats.

MATERIAL AND METHODS

? Male Wistar rats were divided into four groups: Control, N (G)‐nitro‐L‐ arginine methyl ester (L‐NAME; 20 mg/rat/day), BAY 41‐2272 (20 mg/kg/day) and L‐NAME + BAY 41‐2272. ? Rats were treated with L‐NAME concomitantly with BAY 41‐2272 for 4 weeks. ? Concentration–response curves to acetylcholine (ACh) and sodium nitroprusside (SNP), along with the nitrergic relaxations (1–32 Hz) were obtained in rat corpus cavernosum (RaCC). ? The RaCC contractile responses to the α₁‐adrenoceptor agonist phenylephrine (PE) were obtained.

RESULTS

? Acetylcholine (0.01–1000 µmol/L) produced concentration‐dependent relaxing responses in RaCC that were significantly enhanced (P < 0.05) in BAY 41‐2272‐treated rats. ? The ACh‐induced relaxations were largely reduced in L‐NAME‐treated rats, and co‐treatment with BAY 41‐2272 failed to significantly modify these impaired relaxations. ? The SNP‐induced relaxations were modified neither by L‐NAME nor by co‐treatment with BAY 41‐2272. ? The nitrergic relaxations were significantly amplified in BAY 41‐2272‐treated rats (at 16 and 32 Hz). A significant reduction in the nitrergic relaxations was observed in L‐NAME‐treated rats, an effect largely restored by co‐treatment with BAY 41‐2272. ? The contractile RaCC responses produced by PE (0.001–100 µmol/L) were significantly higher (P < 0.05) in L‐NAME‐treated rats, and co‐treatment of L‐NAME with BAY 41‐2272 nearly restored these enhanced contractile responses.

CONCLUSION

? Four‐week therapy with BAY 41‐2272 prevents the impaired corpus cavernosum relaxations of rats treated chronically with L‐NAME, indicating that accumulation of cyclic guanosine monophosphate into erectile tissue counteracts the NO deficiency.     

Cardiovascular simulator improvement: pressure versus volume loop assessment

This article presents improvement on a physical cardiovascular simulator (PCS) system. Intraventricular pressure versus intraventricular volume (PxV) loop was obtained to evaluate performance of a pulsatile chamber mimicking the human left ventricle. PxV loop shows heart contractility and is normally used to evaluate heart performance. In many heart diseases, the stroke volume decreases because of low heart contractility. This pathological situation must be simulated by the PCS in order to evaluate the assistance provided by a ventricular assist device (VAD). The PCS system is automatically controlled by a computer and is an auxiliary tool for VAD control strategies development. This PCS system is according to a Windkessel model where lumped parameters are used for cardiovascular system analysis. Peripheral resistance, arteries compliance, and fluid inertance are simulated. The simulator has an actuator with a roller screw and brushless direct current motor, and the stroke volume is regulated by the actuator displacement. Internal pressure and volume measurements are monitored to obtain the PxV loop. Left chamber internal pressure is directly obtained by pressure transducer; however, internal volume has been obtained indirectly by using a linear variable differential transformer, which senses the diaphragm displacement. Correlations between the internal volume and diaphragm position are made. LabVIEW integrates these signals and shows the pressure versus internal volume loop. The results that have been obtained from the PCS system show PxV loops at different ventricle elastances, making possible the simulation of pathological situations. A preliminary test with a pulsatile VAD attached to PCS system was made.