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Biomedical subjects

M A Ruiz

Publications and source records attributed to M A Ruiz.

At least 55 records · Page 3Linked to original sources
PubMed1996

HIV and infections of similar transmission patterns in a drug injectors community of Santos, Brazil.

To study the prevalence of HIV and infections with related transmission patterns, we interviewed and obtained blood samples from 220 injecting drug users (IDUs), sampled by snowballing, from the city of Santos in the state of São Paulo, Brazil, where the estimated number of IDUs (10,000) comprises approximately 2% of the entire population. Seroprevalence of HIV, hepatitis B and C, syphilis, and HTLV (1 and 2) was assessed and compared with that in 197 blood donors from the same city, matched for age and gender. Risk behavior related to HIV was assessed by a standard questionnaire applied to the IDU sample. Univariate and multivariate analyses of the risk factors were performed. Seroprevalences found were 62% for HIV, 75% for HCV, 75% for HBV, 34% for syphilis, and 25% for HTLV (1 and 2) among IDUs, which compare with 0.0%, 2%, 23%, 12%, and 1% for blood donors, respectively. The risk for parenterally transmitted infections in this IDU community was higher than that for sexually transmitted infections (odds ratio for syphilis, 3.57; hepatitis B, 10.0; and hepatitis C, 100). The results of the mutivariate risk analysis showed that daily rate of ID use >5 times/day (OR = 6.73), not changing behavior to avoid AIDS (OR= 3.28), ID use >15 days/month (OR = 2.72), and ID use in the last 2 months (OR = 2.23) were the risk behaviors significantly associated with HIV infection.

Adolescent↗
PubMed1996

The meaning of psychological symptoms: effectiveness of a group intervention with hypochondriacal patients.

A group treatment for hypochondriasis was administered to 14 subjects. It was based on Barsky, Geringer and Wool (1988) [General Hospital Psychiatry, 10, 322-327] cognitive-behavioral formulation and presented as an educational course to explain the origins of an enhanced perception of somatic symptoms. Initially, one experimental group (N = 9) and a waiting list control (N = 8) were formed. Experimental subjects showed significant reductions in illness fears and attitudes, reported somatic symptoms and dysfunctional beliefs. Waiting-list controls also changed some illness attitudes, but showed no change in somatic symptoms and increased the number of visits to doctors. Experimental and control subjects differed on several change measures. Afterwards, part of the waiting list subjects (N = 5) received treatment. Overall, treatment was effective for the target measures and produced long-term positive effects on other fears, dysphoric mood and well-being. After treatment, subjects were significantly more extroverted, open and warm. The clinical impression was that treatment was not limited to less severe cases.

Adolescent↗
PubMed1996

Adsorption of betamethasone disodium phosphate on ethylcellulose latex: an electrokinetic study.

The use of polymer latexes as vehicles for drug transport and controlled delivery in the body is a very active research field in applied colloid science. In this work, the polymer chosen is a commercially available ethylcellulose-based material, Aquacoat. We report electrokinetic (electrophoresis) data on this polymer in the presence of the soluble glucocorticoid betamethasone disodium phosphate (BMP). The electrophoretic mobility of the particles becomes more negative as the concentration of BMP in the medium is increased between 10(-5) and 10(-3) M, this demonstrating that the negative species produced upon dissolution of BMP adsorb on the particles; this trend is reversed for higher concentrations due to the phenomenon of double layer thickness. When pH is increased at constant BMP concentration, the negative mobility increases in absolute value, but it reaches lower values than attained in the absence of BMP. This is interpreted as another consequence of adsorption, since the ionization constants of the phosphate and sulfate groups are different. Such adsorption is confirmed and measured by spectrophotometric analysis of the supernatants after centrifugation of the suspensions; it is found that the adsorption density increases with the initial concentration of BMP in the medium, an almost vertical isotherm being obtained for concentrations above 5 x 10(-3) M, possibly due to bidimensional aggregation of the adsorbed molecules and multilayer adsorption at higher concentrations. It is found that the adsorbed amount increases with the ionic strength of the medium as a consequence of screening of the particle and BMP charges, whereas these electrostatic contributions to adsorption manifest also in the pH dependence of adsorption. IR analysis of the particles after equilibration with BMP solutions of increasing concentration agrees well with adsorption data.

Adsorption↗
PubMed1996

Effect of amino acids on the stability properties of nitrofurantoin suspensions. Flocculation and redispersion compared with interaction energy curves.

The influence of the addition of amino acids, lysine, alanine and glutamic acid on the properties of nitrofurantoin suspensions was investigated. Flocculation and redispersability was investigated, taking into account the electrical properties of the nitrofurantoin/solution interface. We conclude that lysine and glutamic acid, but not alanine, would be suitable amino acids for control of the stability of nitrofurantoin suspensions.

Alanine↗
PubMed1994

Bone marrow morphology in patients with neutropenia due to chronic exposure to organic solvents (benzene): early lesions.

The authors present the histological and cytological features of bone marrow (BM) in 152 employees from the steel plant of Cubatão (S. Paulo-Brazil) who presented with neutropenia, due to chronic exposure to benzene and its homologues. All patients were male. Mean age was 35 years. At the time of this study, all patients were removed from risk areas because of the hematological abnormality. BM morphology was characterized by a hypocellular hemopoiesis (82%). Decrease of the granulocytic precursors (86%) was the most outstanding feature. Erythroid and megakaryocytic series were diminished in 40% and 57% of the cases, respectively. Eosinophilia in BM was observed in 71% of the cases. Cell atypias and stromal changes (necrosis, increase in reticulin fibres) were frequent.

Adult↗
PubMed1994

Effect of flumazenil on recovery after midazolam and propofol sedation.

BACKGROUND: Flumazenil, a benzodiazepine antagonist, reverses midazolam-induced sedation and amnesia. We designed a double-blind study to evaluate the effects of flumazenil on patient outcome when flumazenil was used to reverse large or small doses of midazolam as part of standardized monitored anesthesia care. METHODS: Ninety-nine healthy consenting women undergoing breast biopsy procedures with local anesthesia were randomly assigned to one of four treatment groups: group 1, propofol-placebo (control); group 2, propofol-flumazenil; group 3, midazolam-placebo; or group 4, midazolam-flumazenil. All patients received intravenous midazolam 2 mg and intravenous fentanyl 50 micrograms, followed by an infusion of either propofol 25-150 micrograms.kg-1.min-1 or midazolam 0.5-4 micrograms.kg-1.min-1. At the end of the operation, patients were intravenously administered either 10 ml saline (groups 1 and 3) or flumazenil 1 mg in 10 ml saline (groups 2 and 4). Amnesia was assessed by determining recall of pictures shown before and after the procedure. Subjective feelings of sedation, anxiety, clumsiness, and fatigue were evaluated using 100-mm visual analogue scales preoperatively and at 30-min intervals in the recovery room. Cognitive function was assessed using the digit-symbol substitution test at similar intervals. Early recovery was evaluated by the ability of the patients to be transferred directly from the operating room to the step-down unit, as well as by times to ambulation and discharge. A standardized questionnaire and telephone interview were used to assess "resedation" and other postdischarge side effects. RESULTS: Flumazenil (1 mg) enhanced early recovery and picture recall after high-dose (group 4) but not low-dose (group 2) midazolam. Only 32% of patients in group 3 were transferred directly to the step-down unit compared with 85% in group 4 (P < 0.05). Flumazenil significantly improved visual analogue scale and digit-symbol substitution test scores at the 30- and 60-min testing intervals (P < 0.05). At the 90-min interval, there were no significant differences between groups 3 and 4. Compared with group 3 (84 +/- 22 min), patients in groups 1, 2, and 4 were ready for discharge significantly earlier (60 +/- 23, 65 +/- 21, and 67 +/- 27 min, respectively) (P < 0.05). However, 33% of the patients in group 4 reported resedation after discharge (vs. 0-8% in the other three study groups) (P < 0.05). CONCLUSIONS: Early recovery after breast biopsy procedures with midazolam sedation and flumazenil reversal is similar to recovery after propofol sedation. However, the beneficial effects of flumazenil were apparent only during the first 60 min after the procedure and resedation after discharge is an important consideration in the outpatient setting.

Adult↗
PubMed1993

[Hematologic changes in patients chronically exposed to benzene].

A study was carried out into the hematological abnormalities of peripheral blood bone marrow in patients chronically exposed to benzene. The metabolic biotransformation and the mechanisms involved in toxicity are described. Hematological data are described and discussed. Macrocytosis and lymphopenia are the earliest hematological signs of benzene toxicity. Bone marrow abnormalities are demonstrated by the complementary methods of cytology and histology. Global hypocellularity was mainly due to the granulocytic series. Mastocytosis, eosinophilia and magakariocytic abnormalities are also presented. Inflammatory abnormalities and signs of dismyelopoiese could also be observed. The importance of peripheral blood abnormalities and the need for a critical approach to this important public health problem are emphasized.

Benzene↗
PubMed1990

Metabolic effects of the delay in obliteration of the umbilical cord in the newborn rat.

The effect of delay in obliteration of the umbilical cord on the time-courses of liver glycogen, blood glucose and lactate concentrations and blood PO2, PCO2 and pH during the first 6 h of extrauterine life were studied. Obliteration of the umbilical cord 2 h after delivery resulted in an increase in liver glycogenolysis without significantly affecting the other parameters studied. A 6-hour delay in obliteration of the umbilical cord increased lactiacidemia and decreased blood PO2 and pH without significantly affecting the other parameters studied. A supply of pure oxygen to the newborns decreased lactiacidemia and increased PO2, although the differences between obliterated and nonobliterated newborns remained. These results suggest that hypoxia due to the persistence of placental circulation results in an increase in lactiacidemia as a consequence of a decrease in lactate utilization.

Animals↗
PubMed1989

The influence of chemotherapy on plasma coagulation and fibrinolytic systems in lung cancer patients.

After the administration of cytostatic drugs, an increase in thromboembolic phenomena has been described in cancer patients. The authors studied the changes in plasmatic coagulation and fibrinolysis in 40 patients with nonoperable Stage III and IV lung cancer after cytostatic chemotherapy. The results show significant postchemotherapy increases in fibrinopeptide A levels, as well as a decrease in fibrinolytic activity reflected by a drop in functional tissue activator. Also the authors studied the potential accumulative effect of three chemotherapy cycles. A significant increase in functional plasminogen activator inhibitor has been noted. Chemotherapy is apparently capable of conditioning a decrease in fibrinolytic activity in these cancer patients that could be related to the enhanced tendency to developing thromboembolic phenomena after cytostatic chemotherapy.

Aged↗