[Quantitative cultures from catheters, using the Brun Buisson technique]

The objective of this collaborative work carried out in the Fundación Favaloro and the Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia, was to determine optimal conditions for incubation (time and atmosphere) of quantitative cultures of catheters processed according to the technique of vortex agitation (Brun Buisson method). From 689 processed catheters, 551 yielded negative cultures. From the 138 positive cultures, 125 yielded monomicrobial cultures and 13 polimicrobial cultures (total number of microorganisms was 151). In the last situation each micoorganism was considered on an individual basis. A total of 58 episodes of catheter related bacteremias occurred, being 52 monomicrobial and 6 polimicrobial (total number of microorganisms was 64). When colony counts were compared in aerobic and in 5-10% CO2 atmospheres, a very good correlation was obtained (p = 0.27; r2 = 0.9268). No advantage was observed by incubating plates for more than 48 hours. Colony counts performed at the second versus the third day, and at the second day versus the seventh, gave very good correlation (p = 0.10 and r2 = 0.9996; p = 0.31 and r2 = 0.9995, respectively).

Experimental study of the efficacy of vancomycin, rifampicin and dexamethasone in the therapy of pneumococcal meningitis

The object of the study was to assess the efficacy of rifampicin and the combination of rifampicin plus vancomycin in a rabbit model of experimental penicillin-resistant pneumococcal meningitis. We also studied the effect of concomitant dexamethasone on the CSF antibiotic levels and inflammatory parameters. The rabbit model of pneumococcal meningitis was used. Groups of eight rabbits were inoculated with 106 cfu/mL of a cephalosporin-resistant pneumococcal strain (MIC of cefotaxime/ceftriaxone 2 mg/L). Eighteen hours later they were treated with rifampicin 15 mg/kg/day, vancomycin 30 mg/kg/day or both plus minus dexamethasone (0.25 mg/kg/day) for 48 h. Serial CSF samples were withdrawn to carry out bacterial counts, antibiotic concentration and inflammatory parameters. Rifampicin and vancomycin promoted a reduction of >3 log cfu/mL at 6 and 24 h, and cfu were below the level of detection at 48 h. Combination therapy with vancomycin plus rifampicin was not synergic but it had similar efficacy to either antibiotic alone and it was able to reduce bacterial concentration below the level of detection at 48 h. Concomitant use of dexamethasone decreased vancomycin levels when it was used alone (P< 0.05), but not when it was used in combination with rifampicin. Rifampicin alone at 15 mg/kg/day produced a rapid bactericidal effect in this model of penicillin-resistant pneumococcal meningitis. The combination of vancomycin and rifampicin, although not synergic, proved to be equally effective. Using this combination in the clinical setting may allow rifampicin administration without emergence of resistance, and possibly concomitant dexamethasone administration without significant interference with CSF vancomycin levels.

Characterization of regions in the GP5 protein of porcine reproductive and respiratory syndrome virus required to induce apoptotic cell death

Expression of the GP5 protein of porcine reproductive and respiratory syndrome virus in mammalian cells using a recombinant vaccinia virus has been shown to induce strong cytotoxicity due to apoptotic death. We have now developed a transient expression system that allows the observation and quantitation of the cell death due to GP5 synthesis, taking advantage of the reduction that this protein induces in the expression of two different co-transfected reporter genes. In this way, we are able to study the regions in GP5 implicated in apoptosis induction. The first 119 aminoacids constitute a region capable of fully inducing apoptosis, aminoacids 90-119 having a fundamental role. On the contrary, the C-terminal region is unable by itself of cell death induction and, moreover, is dispensable for this phenotype. We have also observed that induction of apoptosis is independent of cleavage of the N-terminal putative signal sequence in GP5 or N-glycosylation of this protein.

[Correlation between reaction time and bradykinesia in Huntington's disease]

BACKGROUND

Bradykinesia is the clinical feature of Huntington's disease most closely related to functional discapacity and stage, probably as a consequence of spreading of neuronal injury. The aim of the present article is to verify whether a choice reaction time could be considered an estimate measurement of clinical bradykinesia, and its possible relationships with other evolutive parameters such as functional discapacity, clinical stage and prefrontal executive dysfunction.

METHODS

Fifteen patients were studied (9 in advanced stage and 6 initials), equal number of controls and 3 asymptomatic gene carriers. We used clinical bradykinesia and functional capacity scales, an extensive prefrontal battery and a computerized paradigm of reaction time.

RESULTS

Clinical bradykinesia and reaction time are closely related. The associations between reaction time with those parameters indicatives of prefrontal dysfunction, functional discapacity and clinical stage are closer and more significatives than those that could be established with clinical bradykinesia.

CONCLUSIONS

Reaction time is an objective measurement of global motor slowness that allow us assigning each subject to a specific stage, and avoid possible errors derived from interobserver bias in clinical scales.

Protein orientation affects the efficiency of functional protein transplantation into the xenopus oocyte membrane

Xenopus oocytes incorporate into their plasma membrane nicotinic acetylcholine receptors (nAChRs) after intracellular injection of lipid vesicles bearing this protein. The advantage of this approach over the classical oocyte expression system lies in the transplantation of native, fully processed proteins, although the efficiency of functional incorporation of nAChRs is low. We have now studied the incorporation into the oocyte membrane of the Torpedo chloride channel (ClC-0), a minor contaminant protein in some nAChR preparations. nAChR-injected oocytes incorporated functional ClC-0: i) in a higher number than functional nAChRs; ii) retaining their original properties; and iii) with a right-side-out orientation in the oocyte membrane. In an attempt to elucidate the reasons for the low efficiency in the functional incorporation of nAChRs into the oocyte membrane, we combined electrophysiological and [125I]alpha-bungarotoxin-binding experiments. Up to 3% of injected nAChRs were present in the oocyte plasma membrane at a given time. Thus, fusion of lipoproteosome vesicles to the oocyte plasma membrane is not the limiting factor for an efficient functional transplantation of foreign proteins. Accounting for the low rate of functional transplantation of nAChRs is their backward orientation in the oocyte membrane, since about 80% of them adopted an out-side-in orientation. Other factors, including differences in the susceptibility of the transplanted proteins to intracellular damage should also be considered.

Protein orientation affects the efficiency of functional protein transplantation into the xenopus oocyte membrane

Xenopus oocytes incorporate into their plasma membrane nicotinic acetylcholine receptors (nAChRs) after intracellular injection of lipid vesicles bearing this protein. The advantage of this approach over the classical oocyte expression system lies in the transplantation of native, fully processed proteins, although the efficiency of functional incorporation of nAChRs is low. We have now studied the incorporation into the oocyte membrane of the Torpedo chloride channel (ClC-0), a minor contaminant protein in some nAChR preparations. nAChR-injected oocytes incorporated functional ClC-0: i) in a higher number than functional nAChRs; ii) retaining their original properties; and iii) with a right-side-out orientation in the oocyte membrane. In an attempt to elucidate the reasons for the low efficiency in the functional incorporation of nAChRs into the oocyte membrane, we combined electrophysiological and [125I]alpha-bungarotoxin-binding experiments. Up to 3% of injected nAChRs were present in the oocyte plasma membrane at a given time. Thus, fusion of lipoproteosome vesicles to the oocyte plasma membrane is not the limiting factor for an efficient functional transplantation of foreign proteins. Accounting for the low rate of functional transplantation of nAChRs is their backward orientation in the oocyte membrane, since about 80% of them adopted an out-side-in orientation. Other factors, including differences in the susceptibility of the transplanted proteins to intracellular damage should also be considered.

[Tonsillectomy by electrical dissection: risk factors of postoperative hemorrhage in children]

OBJECTIVE

To identify pre or intraoperative risk factors that could indicate a higher risk for post-tonsillectomy hemorrhage (PTH) in children undergoing electrocautery dissection. SET-UP: Primary referral hospital.

DESIGN

A retrospective study of 163 post-tonsillectomy children comparing 7 cases of PTH with 156 cases with no PTH.

SAMPLE

This study includes children under the age of 18 that underwent tonsillectomy by dissection between 1997 and 2000.

OUTCOME PARAMETERS

Age, sex, height, weight, body mass index, hemoglobin level, hematocrit, platelet count activated partial thromboplastin time (APTT), fibrinogen, ASA index (physical state classification of the American Society of Anesthesiology) and type of hemostasis.

RESULTS

Prevalence of PTH was 4.29% in the cohort sample. The risk of PTH in children following tonsillectomy by electrodissection is significantly increased in patients over 15 years of age (OR = 8.46, p = 0.04) and when ligatures are used for hemostasis (OR = 8.62, p = 0.02). Activated partial thromboplastin time > or = 32 seconds is marginally significant (OR = 7.82, p = 0.05).

CONCLUSIONS

Our findings show that tonsillectomy by electrodissection has an increased risk of bleeding in older children and when ligatures are used for hemostasis.

Spatio-temporal patterns of brain magnetic activity during a memory task in Alzheimer's disease

The brain magnetic activity patterns in a high load probe-letter (targets and distractors) memory task were examined in patients with Alzheimers's disease (AD) and elderly controls. Control subjects showed a higher number of activity sources over the temporal and parietal cortex between 400 and 700 ms after stimulus onset. However, AD patients showed a higher number of sources over the frontal motor areas, including Broca's and the insula. The number of activity sources on the left parietal areas in response to the target stimuli predicted the AD score oncognitive (MMSE, CAMCOG) and functional staging (FAST) scales. These results suggest that a high information load reveals a deficient functioning of phonological store and reduced task-related activity in temporal and parietal areas, manifesting in a rapid information trace decay. The increased levels of activity in motor areas may reflect a compensatory strategy in an attempt to facilitate rehearsal speed.

Relationship between penicillin and cephalosporin resistance of Streptococcus pneumoniae strains and its inflammatory activity in the experimental model of meningitis

Using a rabbit model of meningitis, we sought to compare the inflammatory activity induced by three pneumococcal strains with different susceptibilities to penicillin and cephalosporins, belonging to the serotypes 3, 6B and 23F at different inoculum sizes. These serotypes are prevalent in Western Europe and are believed to produce a moderate-to-severe cerebrospinal fluid (CSF) inflammatory response. Only minor differences were observed in the inflammatory activity evoked by the three strains in the subarachnoid space, and most were probably related to differences in bacterial counts. Infection by serotype 23F caused secondary bacteremia in all challenged animals. Our findings reinforce the concept that resistant pneumococci are not more virulent, a fact that should be taken into account when evaluating the efficacy of different anti-pneumococcal therapies. However, the frequent induction of secondary bacteremia by the resistant serotype 23F requires further study.

Neural processing to visual stimuli in a three-choice reaction-time task

Some authors have suggested that certain components of the event-related potentials (ERPs) reflect underlying stages in the discrimination process. Previous studies have shown that in an auditive three-choice reaction-time task the discrimination is accomplished as a two-stage process, with the more frequently occurring stimulus discriminated at an earlier point than the rarer stimulus and the subjects could be classified as fast and slow responders in function of their response to the most frequent of the three tones. We continuously recorded the electrocerebral activity (EEG) from the scalp and the electromyographic activity (EMG) from the responding muscles in a visual three-choice reaction-time task in 10 strictly right-handed subjects. EEG and EMG responses were subsequently analyzed off-line by aligning them by the onset of either the stimulus (stimulus-synchronized) or the response (response-synchronized). The results suggest that processes of visual stimuli evaluation and response execution are continuously integrated. The discrimination and response systems to visual stimuli is accomplished as a three-stage process, one to frequent tone, another for rare 1, and the last for rare 2. The subjects were classified as fast and slow responders in function of their response to the most frequent of the three tones.

Dermatitis to captopril

BACKGROUND

reports on delated cutaneous reactions to captopril have been seldom reported. Captopril is an angiotensin-converting enzyme (ACE) inhibitor and their cutaneous side-effects are documented, but little has been published concerning the usefulness of patch test when they occur. We presented the case of a patient who developed a cutaneous reaction induced by captopril with positive patch test.

METHODS AND RESULTS

patch testing was performed with captopril, other ACE (enalapril, lisinopril ramipril), and European standard series. Following, we performed a double-blind oral challenge test with drugs who results was negative. Positive reaction were obtained to captopril at 4 days and the others test being negative. The same test were negative in five control patients. The patient tolerated enalapril, and lisinopril without problems.

CONCLUSION

the allergological studies confirmed sensitisation to captopril and tolerance to lisinopril, and enalapril. When patch test are performed with several drugs of the same family, results seem to indicate an absence of cross-sensitivity, but in several patients, oral provocation test were needed because patch test gave no conclusive information.

[Evaluation of the treatment of benign paroxysmal positional vertigo with the DHI-S questionnaire]

Benign paroxysmal positional vertigo (BPPV) is a recurrent chronic disease and its handicap is usually underestimated. The aim of this study is to determine the impact of the treatment by Epley maneuver on short-term BPPV-related quality of life. Forty-two individuals with BPPV were included: 39 with posterior canal affected, 2 with the lateral canal and one with the anterior canal. Diagnosis was established if a consistent clinical history was found and Dix-Hallpike test (DHT) in cases with canal posterior involvement. Subjects with positive DHT were treated by a single Epley maneuver and were recommended to avoid supine for the next 48 hours. The BPPV relapses were investigated at 7th and 30th day post-treatment. BPPV-associated quality of life was evaluated by the Dizzness Handicap Inventory Short-form (DHI-S) at days 1st and 30th post-treatment. Total and partial scores for emotional, physical and functional subscales were compared by Wilcoxon test for paired samples. Dix-Hallpike test was found positive in el 59% individuals (23/39), and 41% cases did not required any treatment. Among 23 patients treated with Epley maneuver, DHT was found negative in 90% at 30th day follow-up. Mean and standard deviation of the total scores obtained in the DHI-S at the first day were 19.22 +/- 9.66 in the DHT positive-patients and 19.79 +/- 10.14 in the whole group (DHT positive or negative). These scores significantly decreased to 10.84 +/- 10.99 at 30 days post-treatment (p = 0.002 and p = 0.001, respectively). In conclusion, the DHI-S is a specific health questionnaire able to assess BPPV-related health and the effectiveness of treatment.

The phosphodiesterase inhibitory selectivity and the in vitro and in vivo potency of the new PDE5 inhibitor vardenafil

We investigated the potency and the selectivity profile of vardenafil on phosphodiesterase (PDEs) enzymes, its ability to modify cGMP metabolism and cause relaxation of penile smooth muscle and its effect on erections in vivo under conditions of exogenous nitric oxide (NO) stimulation. PDE isozymes were extracted and purified from human platelets (PDE5) or bovine sources (PDEs 1, 2, 3, 4 and 6). The inhibition of these PDEs and of human recombinant PDEs by vardenafil was determined. The ability to potentiate NO-mediated relaxation and influence cGMP levels in human corpus cavernosum strips was measured in vitro, and erection-inducing activity was demonstrated in conscious rabbits after oral administration together with intravenous doses of sodium nitroprusside (SNP). The effects of vardenafil were compared with those of the well-recognized PDE5 inhibitor, sildenafil (values for sildenafil in brackets). Vardenafil specifically inhibited the hydrolysis of cGMP by PDE5 with an IC50 of 0.7 nM (6.6 nM). In contrast, the IC50 of vardenafil for PDE1 was 180 nM; for PDE6, 11 nM; for PDE2, PDE3 and PDE4, more than 1000 nM. Relative to PDE5, the ratios of the IC50 for PDE1 were 257 (60), for PDE6 16 (7.4). Vardenafil significantly enhanced the SNP-induced relaxation of human trabecular smooth muscle at 3 nM (10 nM). Vardenafil also significantly potentiated both ACh-induced and transmural electrical stimulation-induced relaxation of trabecular smooth muscle. The minimum concentration of vardenafil that significantly potentiated SNP-induced cGMP accumulation was 3 nM (30 nM). In vivo studies in rabbits showed that orally administered vardenafil dose-dependently potentiated erectile responses to intravenously administered SNP. The minimal effective dose that significantly potentiated erection was 0.1 mg/kg (1 mg/kg). The selectivity for PDE5, the potentiation of NO-induced relaxation and cGMP accumulation in human trabecular smooth muscle and the ability to enhance NO-induced erection in vivo indicate that vardenafil has the appropriate properties to be a potential compound for the treatment of erectile dysfunction. Vardenafil was more potent and selective than sildenafil on its inhibitory activity on PDE5.

[Perinatal Information System. Incorporation latency and impact on perinatal clinical registry]

The Perinatal Information System (SIP) is a clinical record, local management and quality assurance software standard in Latin America and the Caribbean. The time to implement SIP in a Maternity Hospital is evaluated as well as the effect of statistics on perinatal health indicators in subsequent years. In the sample of 20 Maternity Hospitals (5 Countries, 40% Private and 60% Public) 85% had a reliable information system by the third year of use of SIP. 15% of hospitals still had problems at that time that were already clear during the second year, a time corrective measures can still be taken. The evaluation of the impact of yearly reports shows that 58% of recommendations were fulfilled, specially those regarding the complete filling-in of clinical records (62%) and to a lesser extent variables that reflect clinical practices and organization of services (52%). The conclusion is that Maternity Hospitals in Latin America and the Caribbean have the capacity to adopt a complex tool of computerized clinical records for quality assurance of perinatal care and monitoring of health indicators.

Risperidone safety and efficacy in the treatment of bipolar and schizoaffective disorders: results from a 6-month, multicenter, open study

BACKGROUND

The goal of this study was to assess the efficacy and safety of risperidone in bipolar and schizoaffective disorders.

METHOD

541 patients entered this open, multicenter, 6-month study. Patients were entered provided that they fulfilled DSM-IV criteria for bipolar disorder or schizoaffective disorder, bipolar type, during a manic, hypomanic, mixed, or depressive episode. Risperidone was added to any previous mood-stabilizing medication that the patients were taking. Efficacy was assessed with the Young Mania Rating Scale (YMRS), the Hamilton Rating Scale for Depression (HAM-D), the Positive and Negative Syndrome Scale (PANSS), and the Clinical Global Impressions scale (CGI). Extrapyramidal symptoms (EPS) were assessed using the UKU Side Effect Rating Scale.

RESULTS

430 patients completed the study. Addition of risperidone produced highly significant improvements (p < .0001) on the YMRS and HAM-D at both 6 weeks and 6 months and on the CGI and the scales of the PANSS at both 4 weeks and 6 months. There was a significant reduction in UKU total and subscale scores at 6 months. The mean dose of risperidone was 3.9 mg/day. There was no single case of new-emergent tardive dyskinesia, and there was a very low incidence of exacerbation of mania within the first 6 weeks (2%). Adverse events were few and mostly mild. the most frequent being EPS and weight gain.

CONCLUSION

This large study provides additional evidence that risperidone is effective and well tolerated when combined with mood stabilizers in the treatment of bipolar disorder and schizoaffective disorder, bipolar type. Previous concerns about exacerbation of manic symptoms were not confirmed.