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Biomedical subjects

R Ruiz

Publications and source records attributed to R Ruiz.

At least 19 recordsLinked to original sources
PubMed1996

[Relationship between blood levels of sex hormone binding globulin, testosterone levels in blood and saliva and body morphology in premenopausal women].

BACKGROUND: The concentrations of the globulin binding of sexual hormones (GBSH) and serum and saliva testosterone were studied, as well as the free testosterone index (FTI), in a group of 75 premenopausic women of 42 years of age. These concentrations were correlated with the body mass index (BMI) and the relationship between the waist and hip perimeters (WHI) as an index of body fat distribution. MATERIAL AND METHODS: Anthropometric measurements were performed in all the women studied. The BMI was used to classify the women as obese or not obese, while the WHI was used to classify fat distribution as android or gynoid type. The hormone determinations were carried out by radioimmunoassay and the GBSH by fluorescence immunoassay. RESULTS: A significant positive correlation was observed between FTI and BMI (p = 0.024) and a negative correlation was seen between GBSH and WHI (p = 0.024). A significant decrease was found in the GBSH levels in obese women with respect to those who were not obese (p = 0.025) and between those with android fat distribution versus gynoid fat distribution (p = 0.032). CONCLUSIONS: The modifications observed in the concentrations of the globulin binding sexual hormone in obese premenopausic women and the absence of the same in the free testosterone indexes may be explained because of other steroids such as androstenodiol and dehydrotestosterone are elevated. The measurement of globulin binding sexual hormone concentrations may be an early marker of alteration in the androgenic status in obese women.

Adult↗
PubMed1995

Community-based assessment of safety and immunogenicity of the whole cell plus recombinant B subunit (WC/rBS) oral cholera vaccine in Peru.

Every year since its introduction in 1991, there have been epidemics of cholera in Lima, Peru. Vaccination is one approach to the control of cholera. A pilot study was conducted to assess the safety and immunogenicity of a whole cell plus recombinant B subunit (WC/rBS) cholrea vaccine in Lima, Peru. Five hundred and forty-one volunteers aged 2-65 years received two doses two weeks apart of WC/rBS vaccine or Escherichia coli K12 placebo administered in bicarbonate buffered water. Symptoms were monitored on all subjects and blood was collected from 102 persons before the first dose and two weeks after the second dose. Mild post-vaccination gastrointestinal symptoms were reported with equal frequency for both the vaccine and placebo recipients. Among 51 vaccines, 49% had a twofold or greater increase in serum vibriocidal titers (GMT = 78; range < 1:10 to 1:5120); and 92% and 82% developed a twofold or greater serum anti-cholera toxin IgG and IgA response, respectively. Persons with elevated prevaccination vibriocidal titers had a decreased response to the WC/rBS. Age and blood group did not affect the immune response. The WC/rBS vaccine was safe and immunogenic in a group of native Peruvians.

Administration, Oral↗
PubMed1995

Efficacy and tolerability of ciprofloxacin prophylaxis in adult household contacts of patients with cholera.

We conducted a randomized double-blinded study in Lima, Peru, to assess the tolerability and efficacy of a single 250-mg dose of ciprofloxacin in preventing diarrhea and Vibrio cholerae O1 infection among household contacts of bacteriologically confirmed index cases. Adult household contacts with negative baseline stool cultures were included. A total of 213 household contacts were evaluable. The study drugs were well tolerated in both groups. Ciprofloxacin did not prevent the acquisition of V. cholerae O1 infection nor the development of diarrhea. However, in a subgroup of 30 household contacts with positive baseline stool cultures a reduction in the bacterial load and a trend toward prevention of diarrhea were observed among ciprofloxacin recipients. When all household contacts were evaluated, a trend toward prevention of diarrhea was observed with the prophylactic regimen. Ciprofloxacin failed to prevent V. cholerae O1 infections during a period of low transmissibility.

Administration, Oral↗
PubMed1995

Ciprofloxacin for the treatment of cholera: a randomized, double-blind, controlled clinical trial of a single daily dose in Peruvian adults.

We conducted a randomized, double-blind clinical trial to compare ciprofloxacin (250 mg once a day for 3 days) with tetracycline (500 mg four times a day for 3 days) in terms of efficacy and safety in the treatment of moderate-to-severe cholera in Peruvian adults. The baseline characteristics of the groups were similar. A total of 202 patients (102 in the tetracycline group and 100 in the ciprofloxacin group) were included in the efficacy analysis. The clinical and bacteriologic efficacies of the two regimens were similar. The study drugs were well tolerated. We conclude that ciprofloxacin given once a day is as effective as the standard tetracycline regimen for the treatment of cholera in adults. The ciprofloxacin regimen may represent an alternative to the standard treatment in areas where Vibrio cholerae O1 strains that are resistant to commonly used antimicrobials are prevalent.

Administration, Oral↗
PubMed1995

Continuous heart rate variability monitoring through complex demodulation implemented with the fast Fourier transform and its inverse.

UNLABELLED: A new method for the analysis of 24-hour heart rate variability (HRV) using complex demodulation (CDM) implemented with the fast Fourier transform (FFT) and its inverse is described. In a control group with palpitations and dizzy spells (n = 30, 47.2 +/- 16.7 years) the relationship between HRV parameters and subject age was investigated. CDM was used to obtain the amplitude and frequency of the low frequency (LF) and high frequency (HF) oscillations for 8 diurnal hours and 4 nocturnal hours. Differences between the two periods were seen in the LF/HF ratio (2.2 +/- 0.6 vs 1.5 +/- 0.6; P < 0.0001), HF amplitudes (12 +/- 6 vs 17 +/- 7 normalized units, P < 0.05), and in the mean frequency of the LF oscillations (0.078 +/- 0.008 vs 0.073 +/- 0.007 Hz, P < 0.01). During the daytime, age was inversely correlated to HF amplitude (r = -0.60), directly correlated to HF mean central frequency (r = 0.40), inversely correlated to LF amplitude (r = -0.55), and likewise inversely correlated to LF mean central frequency (r = -0.74, P < 0.001). At night, age was only inversely correlated to HF amplitude and to LF mean central frequency. CONCLUSIONS: Continuous HRV monitoring through CDM implemented with the FFT and its inverse differentiates the periods of diurnal activity and nocturnal rest as an expression of two different activity states of the autonomic nervous system. It allows nonstationary analysis, and separately provides mean and instantaneous oscillation amplitude and frequency. Subject age is not equally related to mean amplitude and frequency of a given oscillation.

Adolescent↗
PubMed1995

Evaluation of an immunoturbidimetric assay of serum digoxin without sample pretreatment.

We have evaluated a new turbidimetric immunoassay test (On Line, Roche) for the quantification of digoxin in human serum without sample pretreatment. The assay, automated on a Cobas-Mira clinical analyser, is based on the measurement of the changes in absorbance that occur when digoxin-coated microparticles aggregate with digoxin antibody; the aggregation reaction is partially inhibited by digoxin in the sample. The calibration curve extends up to 6.4 nmol/l, with a wide measuring range, and was stable at least for 10 days during the studied period. The intra- and inter-assay coefficients of variation were in all cases lower than 7%. The detection limit of the assay was 0.256 nmol/l and the linearity, assessed by measuring serial dilutions of poisoned patient sera, showed correlation coefficients higher than 0.998. There is no interference from bilirubin (up to 340 mumol/l) or haemoglobin (up to 7900 mg/l), although a positive interference by lipids was found, which can be avoided by previous delipidation of these sera. No digoxin-like factors were identified affecting digoxin values in a concentration higher than that of the sensitivity of the assay in samples of premature infants, pregnant women, or patients with renal or hepatic failure. Correlation coefficients between the turbidimetric assay and two immunoassays (fluorescence polarization and RIA) were 0.983 and 0.955 respectively, calculated from the assay of 102 and 98 samples. Nevertheless the values obtained by the evaluated assay were proportionally 20% higher, a fact probably related to differences in calibrators.

Bilirubin↗
PubMed1994

Immunoturbidimetry of serum apolipoproteins A-I and B on the Cobas Bio centrifugal analyzer: method validation and reference values.

We describe an immunoturbidimetric assay for estimating the concentration of apolipoproteins (apo) A-I and B in serum with a Cobas Bio centrifugal analyzer. Several analytical variables were studied: pH, temperature, wavelength, reaction time, sample pretreatment, antisera dilution, concentration of NaCl, phosphate buffer, and PEG 6000; a good optical response was obtained with small volumes of sample and antisera. Imprecision was low, with intrarun coefficient of variance (CV) from 1.1 to 2.8% and interrun CV from 1.8 to 3.2%. We demonstrated a good correlation between our method and radial immunodiffusion for apo A-I (r = 0.975) and apo B (r = 0.980). Reference values were calculated from a sample of 494 healthy subjects, and separate intervals for the ratio of apo A-I to apo B in gender and age subgroups were established.

Adult↗
PubMed1994

Diarrheal disease in Peru after the introduction of cholera.

Surveillance was conducted one day each week from December 1992 through May 1993 to determine the clinical features and etiology of diarrhea among a population in a suburban community of Lima, Peru. Patients who had had three or more loose stools during the previous 24 hr were enrolled at a clinic located in the community or at a nearby regional hospital. A total of 143 cases of diarrhea were detected for an overall rate of 7.1 cases per 1,000 population. The enteropathogens isolated were Vibrio cholerae 01 (31%), enterotoxigenic Escherichia coli (22%), and Salmonella, Shigella, Campylobacter, and Aeromonas species (10%). Specimens from the remaining cases were negative for enteropathogens. All isolates of V. cholerae were susceptible to tetracycline, doxycycline, nalidixic acid, norfloxacin, trimethoprim-sulfamethoxazole, trimethoprim, gentamicin, chloramphenicol, and cephalothin. Cases of diarrhea associated with V. cholerae were more common among adults, and more likely to experience severe dehydration and require hospitalization than the non-cholera cases. Data indicated that among the cases diagnosed, V. cholerae and enterotoxigenic E. coli were the more common causes of diarrhea in a suburban community of Lima during the summer season.

Adolescent↗
PubMed1994

Doppler assessment of left ventricular diastolic function in marathon runners.

The possible alteration in diastolic function as a result of physiological left ventricular hypertrophy was evaluated in 28 male marathon runners (mean age 38.6 +/- 5.7 years) using Doppler echocardiography. The subjects were divided into two groups according to the intensity of training and chronometered running times: Group I (n = 14), 80-100 km weekly and marathon times under 3 hours; and Group II (n = 14), 30-50 km weekly and marathon times between 3 hours 15 min. and 3 hours 45 min. A control group (n = 14) of similarly aged sedentary individuals free of cardiovascular disease was used for comparisons. The following parameters were analyzed: (a) left ventricular mass and left ventricular mass index by means of M mode two-dimensional guided echocardiography; (b) peak velocities of E and A waves, E/A peak velocities ratio, E/A velocity-time integrals ratio, E wave/total diastolic flow velocity-time integrals and A wave/total diastolic flow velocity-time integrals (last one also called atrial filling fraction) that, together with E wave deceleration time, were obtained from pulsed Doppler recordings of transmitral flow; (c) isovolumic relaxation time measured from a continuous Doppler recording of aortic ejection flow. Left ventricular mass index was significantly greater in both groups of marathon runners with respect to controls (group I: 121.1 +/- 15.5 vs 81.8 +/- 11.1 g/m2, p < 0.01; group II: 106.5 +/- 21.1 vs 81.8 +/- 11.1 g/m2, p < 0.01), but there were no significant differences in any of the diastolic function parameters analyzed (Anova and Scheffe tests).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[The incidence and significance of late potentials in patients with aborted sudden death].

BACKGROUND: Reentrant ventricular tachycardia and fibrillation probably have different electrophysiological bases. Regional conduction delay during sinus rhythm seems to be greatest in patients with spontaneous sustained ventricular tachycardia than in patients with spontaneous sustained ventricular fibrillation. We investigated the prevalence and significance of late potentials in patients with documented VT or VF in the setting of coronary diseases and other organic heart diseases. PATIENTS AND METHODS: Nineteen patients with a history of spontaneous sustained ventricular tachycardia (11 patients) or fibrillation (8 patients) were studied with signal-averaged ECG. All patients had been resuscitated of sudden cardiac death. All recordings were made in sinus rhythm in an antiarrhythmic free state following the recommendations of the Committee of the European Society of Cardiology for data acquisition and analysis of ventricular late potentials using Signal Averaged Electrocardiography. The relationship between this late potentials and tachyarrhythmia inducibility during electrophysiologic study were established. RESULTS: Abnormal late potentials were found in 79% of patients with sudden cardiac death. Patients with spontaneous ventricular tachycardia had a longer ventricular activation time in sinus rhythm than did patients with spontaneous ventricular fibrillation, but this difference did not reach statistic significance. The only analysis of late potentials could not discern the mechanism of sudden cardiac death. However when sudden cardiac death was caused by a spontaneous ventricular tachycardia, a good correlation between abnormal late potentials and induced ventricular tachycardia by programmed stimulation was found. Quantitative indices of late potentials did not correlate with ventricular tachycardia cycle length. CONCLUSIONS: 1) We have found and elevated incidence of abnormal late potentials in patients with sudden cardiac death, and 2) only when the mechanism of sudden cardiac death was a spontaneous VT, we were able to correlate abnormal late potential with provoked ventricular tachycardia during electrophysiologic study.

Aged↗
PubMed1993

Effect of natural fermentation on carbohydrates, riboflavin and trypsin inhibitor activity of lentils.

Lentils were subjected to natural fermentation for 4 days at 30 degrees C. The pH value fell to 3.8 during the process. alpha-Galactosides and sucrose were not detected in fermented lentils but a significant increase in the fructose content was observed. In fermented lentils the neutral detergent fibre, cellulose and hemicellulose contents decreased and the lignin content increased. After fermentation the riboflavin content was higher and the trypsin inhibitor activity decreased.

Carbohydrates↗
PubMed1993

Extracellular somatostatin measured by microdialysis in the hippocampus of freely moving rats: evidence for neuronal release.

Intracerebral microdialysis combined with a sensitive and specific radioimmunoassay was used to monitor the neuronal release of somatostatin (somatostatin-like immunoreactivity, SLI) in the dorsal hippocampus of freely moving rats. The sensitivity of the radioimmunoassay was optimized to detect < 1 fmol/ml. The basal concentration of SLI in 20-min dialysate fractions (5 microliters/min) collected 24 h after probe implantation was stable over at least 200 min. The spontaneous efflux dropped by 54 +/- 6.4% (p < 0.05) when Ca2+ was omitted and 1 mM EGTA added to the Krebs-Ringer solution and by 65.5 +/- 3.2% (p < 0.05) in the presence of 1 microM tetrodotoxin. Depolarizing concentrations of the Na+ channel opener veratridine (6.25, 25, 100 microM) induced 11 +/- 2 (p < 0.05), 17 +/- 2 (p < 0.05), and 21 +/- 5 (p < 0.01) fold increase in SLI concentration, respectively, during the first 20 min of perfusion. The effect of 100 microM veratridine was blocked by coperfusion with 5 microM tetrodotoxin (p < 0.01) and reduced by 79% (p < 0.01) in the virtual absence of Ca2+. Neuronal depolarization by 20 min of perfusion with Krebs-Ringer solution containing 25 and 50 mM KCl and proportionally lowered Na+ increased the dialysate SLI 4.4 +/- 1 (p < 0.05) and 17 +/- 3 (p < 0.01) fold baseline, respectively. Ten micromolar ouabain, a blocker of Na+,K(+)-ATPase, increased the dialysate SLI 15-fold baseline, on average (p < 0.05), during 80 min of perfusion. The results demonstrate the suitability of brain microdialysis for monitoring the neuronal release of SLI and for studying its role in synaptic transmission.

Animals↗
PubMed1993

Safety, immunogenicity, and excretion pattern of single-dose live oral cholera vaccine CVD 103-HgR in Peruvian adults of high and low socioeconomic levels.

Groups of 122 Peruvian adults of low socioeconomic level (SEL) and 125 of high SEL received a randomly allocated 5 x 10(9)- or 5 x 10(8)-CFU dose of CVD 103-HgR live oral cholera vaccine or a placebo. The vaccine was well tolerated. Vibriocidal seroconversions occurred in 78% of high-SEL and 72% of low-SEL subjects who ingested the high dose and in 78 and 49%, respectively, of those who received the low dose.

Administration, Oral↗
PubMed1993

Evaluation of alkaline phosphatase-labelled ipaH probe for diagnosis of Shigella infections.

The presence of many enteropathogens which are not easily detectable by routine stool culture has led to the development of alternative diagnostic methods. One of these techniques, nucleic acid probe hybridization, has been used to identify Shigella spp. and enteroinvasive Escherichia coli (EIEC) in stool specimens through the detection of genetic material encoded by a specific large approximately 200-kbp virulence-related plasmid. In the present study, an alkaline phosphatase-labelled oligonucleotide probe developed to detect the gene for ipaH, a repetitive genetic sequence thought to be present on both the virulence-related plasmid and the chromosomes of all strains of Shigella and EIEC, was tested in a developing-country setting through a prospective clinical trial. In a group of 219 Peruvian adults and children with acute gastroenteritis, the ipaH probe detected 85% of cases of shigellosis and demonstrated a specificity of 95% when compared with simultaneous detection by several stool culture techniques. Additionally, three cases of EIEC infection which could not be diagnosed by culture methods alone were detected with the ipaH probe and were confirmed by plasmid analysis and Sereny testing. These preliminary results suggest that, with further research, the ipaH probe should prove to be a useful and rapid adjunct in the diagnosis of acute gastroenteritis in developing countries.

Alkaline Phosphatase↗