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We tested whether the absence of an inward rectifier channel in slow skeletal muscle fibers of the frog is regulated by innervation. Normal and denervated slow fibers were identified according to their passive electrical properties. In current-clamp experiments, anomalous rectification was quantified as the ratio of effective resistances for hyperpolarizing and depolarizing pulses. In isotonic potassium solution, this ratio was 0.45 +/- 0.1 (n = 14) for twitch fibers, whereas slow fibers displayed linear behavior [ratio = 1.0 +/- 0.05 (n = 15)]. However, denervated slow fibers showed anomalous rectification (ratio, 0.48 +/- 0.07; n = 5). This finding was supported by voltage-clamp experiments in which denervated slow fibers displayed (1) an inward rectifier current during hyperpolarizing pulses, (2) an increase in this current when [K(+)](o) was increased, and (3) a current inhibition after application of Ba(2+). These results suggest that frog slow fibers, which normally do not possess inward rectifier channels, can express them after denervation.

Objective: The aim of the present study was to determine the frequency of blink reflex alterations and to examine the influence of hyperglycemia in inducing the alterations in recently diagnosed Type 2 diabetes mellitus patients., Methods: A cross-sectional study was carried out on patients having asymptomatic diabetes with a period of evolution under 10 years. In all 47 patients (26 women and 21 men), serum glycemia levels were determined and the latency onset of the blink reflex components were measured., Results: The average patient age was 44.5+/-11.0 (mean+/-SD) years with a diabetes evolution period of 4.3+/-2.9 (mean+/-SD) years. After a fasting serum glucose test, the diabetic patients were catalogued as normoglycemic (< or =126 mg/dl) or as hyperglycemic (> 26 mg/dl) and subjected to a blink reflex test. The results obtained from the diabetic patients were compared with those from a non-diabetic control group. 14.8-31.9% of the diabetic patients showed alterations in blink reflex component latencies. The differences compared with the control group were significant (p<0.05)., Conclusions: Diabetes, as is well-known, can affect the central and peripheral nervous system and there does not appear to be a link between glycemic levels and blink reflex components. However, blink reflex alterations were present even in diabetic patients with a relatively short period of disease evolution.

Effects of cannabinoids on endogenous potassium and calcium currents in HEK293 cells were studied using the whole-cell variant of the patch-clamp technique. The cannabinoid agonists WIN 55,212-2, methanandamide, and anandamide (1 microM) decreased the calcium current by 53.1 +/- 2.6, 47.5 +/- 1.2, and 38.8 +/- 3.1%, respectively, after transfection of human CB1 cannabinoid receptor (hCB1) cDNA into HEK293 cells. The delayed rectifier-like current was not changed after application of these agonists, but the inward rectifier was increased by 94.0 +/- 3.6, 83.7 +/- 5.1, and 63.0 +/- 2.5% after application of WIN 55,212-2, methanandamide, and anandamide, respectively. The effects of the cannabinoid antagonists (AM251, AM281, and AM630) on the inward rectifier and calcium currents were the opposite of those seen with cannabinoid agonists; thus, these compounds act as inverse agonists in this preparation. These results suggest that endogenous inward rectifier and calcium currents are modulated by cannabinoids in HEK293 cells, and that some expressed receptors may be constitutively active.

Objective: To determine the frequency of white-coat hypertension (WCH) and associated risk factors in recently diagnosed hypertensive patients., Material and Methods: A cross-sectional study was carried out from January 1997 to December 1998. The reference population consisted of 195 patients presenting with systemic arterial hypertension (SAH) of less than 1-month evolution and receiving no medical treatment. According to Joint National Committee (JNCVI) criteria, 100 individuals with Stages I, II, and III SAH underwent the following procedures: clinical history; physical examination; electrocardiogram, serum creatinine; urianalysis, and ambulatory monitoring of arterial pressure (AMAP)., Results: A total of 54% of patients were WCH carriers and 46% presented sustained hypertension (SH); 37% of WCH patients and 63% of SH patients had a family history of SAH, while 19.7% of WCH patients and 39.2% of SH patients presented with stage 1 retinopathy. Left ventricular hypertrophy was absent in all WCH patients and present in 21.7% of SH patients. A total of 31% of WCH patients and 50% of SH patients presented electrocardiographic changes., Conclusions: A total of 54% of patients presented WCH. Clinical/epidemiologic profiles of WCH carriers and SH patients are different.

Several reports have shown that inhaled furosemide protects patients with asthma from different bronchoconstrictor agents. However, the effect of this widely used diuretic in acute exacerbation in adults is unproven. There are no reports of furosemide's therapeutic effect in acute asthma in children; thus, the objective of this study was to determine the effectiveness of the combined treatment of furosemide and albuterol in pediatric patients. Using a double-blind design, 20 emergency room patients with an asthmatic exacerbation were studied and randomly assigned to one of the following treatments: (1) furosemide + albuterol (1 and 0.15 mg/kg, respectively) or (2) albuterol (0.15 mg/kg). The forced expiratory volume in one second (FEV1) was measured in each patient before medication and then 30 and 60 minutes after inhalation of the individual drug or drug combination. Neither group differed in age or baseline FEV1. An increase in FEV1 of 22.8 +/- 4.3% (mean +/- SE) in the drug combination group was noted at 60 minutes, and an increase in FEV1 of 18.0 +/- 2.6% in the albuterol group was obtained at the same time. Although the increase in FEV1 was greater in the first group after 1 hour of treatment, this was not significant. These results suggest that inhaled furosemide does not have a synergistic effect with albuterol in the treatment of asthmatic exacerbations in children.

Ultraviolet radiation absorption is responsible for the production of free radicals in damaged cells. This side effect may be neutralized using antioxidant substances. It has been reported that ascorbic acid and d-alpha-tocopherol scavenge reactive oxygen species. In a single-blind controlled clinical trial we studied 45 healthy volunteers divided into three groups. Group 1 received d-alpha-tocopherol 1,200 I.U. daily; Group 2 ascorbic acid 2 g daily and Group 3 ascorbic acid 2 g plus d-alpha-tocopherol 1,200 I.U. daily. Treatment was sustained for one week. Before and after treatment, the minimal erythema dose was determined in all participants. The results show that the median minimal erythema dose increased from 60 to 65 mJ/cm2 in Group 1 and from 50 to 70 mJ/cm2 in Group 3. No modifications were observed in Group 2. We conclude that d-alpha-tocopherol prescribed in combination with ascorbic acid produces the best photoprotective effect.

The recording of currents passing through calcium channels in intact skeletal muscle fibers presents several difficulties. However, use of the three-microelectrode voltage-clamp technique at the end of the fiber provided us with a good approximation of current values in such fibers. Using this technique, we were able to measure the calcium-channel current in slow skeletal muscle fibers of the frog (Rana pipiens) and to quantify the effects of denervation on this current.

Objective: To compare epidemiological characteristics and proportion of participation in a cervical cancer screening program in both, health-care professionals and insured on a health institute's women (Group A and Group B respectively)., Material and Methods: Through questionnaires applied to both healthcare professionals and insured on a health institute's women (n = 96 for each group) randomly selected, a cross-sectional study was performed. To analyze the results, Yates' correction for continuity, was used., Results: The characteristics from A and B groups were respectively: age 35 +/- 10 vs. 41 +/- 5 years (p < 0.001), years of scholarship: 8.3 +/- 5 vs. 12.0 +/- 1 (p < 0.001), frequency of screening test in the last two years: 1.2 +/- 0.4 vs. 1.0 +/- 0.1 (p < 0.001), time elapsed from the last test: 13.6 +/- 15 vs. 12.2 +/- 13 months (p = 0.52), attendance to screening test 55 (57%) vs. 72 (75%), (p < 0.001). Reasons for not attendance to screening test were indolence 13 (14%) vs. 13 (14%) and not enough time 7 (7%) vs. 2 (2%) by both groups, A and B, respectively., Conclusions: The proportion of attendance to cervical cancer screening is higher in health-care professionals than in insured on a health institute's women. The causes for not attendance to screening are the same in both groups.

Objective: After reviewing the existing literature on the subject, a therapeutic, symptomatic alternative in the treatment of hemifacial spasm is proposed., Material and Method: Three patients, all with a 5-year history of hemifacial spasm, were given one 25/250-mg tablet of Levodopa/carbidopa every 12 h. In a cross-over study, the patients were their own controls. The initial treatment phase lasted 1 month, at the end of which treatment was suspended. For an equal amount of time, the patients were given a placebo, after which they were again given Levodopa., Results: After a 2-week period of treatment with Levodopa, the symptomatic aspect of the spasm disappeared in the patients. Upon replacing the drug with the placebo, the spasm reappeared. The patients have since been receiving the treatment with Levodopa, one tablet every 12 h, for a period of 4 years and the reduction of the hemifacial spasm has oscillated at 75%., Conclusion: We suggest the use of Levodopa/carbidopa in the treatment of hemifacial spasm as a therapeutic alternative. This treatment is within the patients' economic reach and more importantly allows them to once again lead normal lives.

The increase in frequency of cesareans that has been noted through 70's, not diminished--like it was expected--perinatal morbidity and mortality. The most important indications to cesarean are distocias, previous cesarean and fetal stress. In 1998 frequency of cesarean deliveries in our hospital was 35% of the pregnancy attended. The claim of this study was to determine risks factors to cesarean in our hospital. A case-control study was performed, selecting 165 cases (cesareans) and 328 controls (via vaginal). It was determined OR of the risks factors and atribuible fraction. Data were analyzed by X2. The most important indications to cesarean delivery were: distocias (39%, n = 64); previous cesarean (23%, n = 41) and fetal stress (11%, n = 21). There was not significative differences in age, height and rupture membrane time in both groups. History of cesarean delivery gave major risk to another surgical intervention (OR = 12.7, p = < 0.0001, atribuible fraction 92%). Nuliparous (OR = 6.6, p < 0.00000, atribuible fraction 85%), second gestation (OR = 1.8, p = 0.002) or history of abortion (OR = 1.8, p = 0.04) were factors mainly associated to cesarean delivery. We concluded that the precise 'medications of this surgical intervention specially in nuliparous or previous cesarean delivery cases must be replanteated to diminish its elevated frequency.