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Biomedical subjects

R S Perez

Publications and source records attributed to R S Perez.

13 recordsLinked to original sources
PubMed2001

Cerebral protection by hypoxic preconditioning in a murine model of focal ischemia-reperfusion.

Sublethal periods of hypoxia or ischemia can induce adaptive mechanisms to protect against subsequent lethal ischemic insults in a process known as ischemic preconditioning. In the present study, we developed a murine model of cerebral preconditioning using several common strains of adult mice. Animals were exposed to sublethal hypoxia (11% oxygen for 2 h) 48 h prior to a 90 min period of transient focal middle cerebral artery occlusion, induced by an intraluminal filament; injury was assessed 24 h later by TTC staining. Infarct volume in hypoxia-preconditioned animals was reduced 46%, 58%, and 64% in C57Bl/6, 129SvEv, and Swiss-Webster ND4 mice relative to their respective untreated controls. This non-invasive murine model of ischemic tolerance should be useful for elucidating the molecular basis of this protection using transgenic and knockout mice.

Animals↗
PubMed2001

Treatment of reflex sympathetic dystrophy (CRPS type 1): a research synthesis of 21 randomized clinical trials.

A blinded meta analysis was performed on randomized clinical trials (RCT) on the medicinal treatment of reflex sympathetic dystrophy (complex regional pain syndrome type I) to assess the methodological quality and quantify the analgesic effect of treatments by calculating individual and summary effect sizes. The internal validity of 21 RCTs was investigated and the quality weighted summary effect size was calculated using a fixed effect model (Glass Delta). The methodological quality ranged from moderate to good (average 46%). Differences were found between the trials in inclusion/exclusion criteria, treatment methods, duration of treatments and trials, and measurement instruments. Statistical analysis was possible for four subgroups; one evaluating the analgesic effects of sympathetic suppressors in general (n = 12), one subgroup concerning the analgesic effects of guanethidine (n = 6), one investigating the analgesic effect of intravenous regional sympathetic blocks (n = 9), and one subgroup (n = 5) evaluating the analgesic effect of calcitonin. Except for the calcitonin subgroup (P = 0.002), the quality-weighted summary effect size of these subgroups were not significant. No significant analgesic effect by sympathetic suppressing agents could be established. Calcitonin seems to provide effective pain relief in reflex sympathetic dystrophy patients. The results of the present study show that weighting methodological quality influences the magnitude of the effect sizes of specific treatment methods. Future studies should control for methodological quality.

Analgesics↗
PubMed1999

Signs and symptoms in complex regional pain syndrome type I/reflex sympathetic dystrophy: judgment of the physician versus objective measurement.

OBJECTIVE: To assess the relation between the subjectively assessed and objectively measured diagnostic signs and symptoms in complex regional pain syndrome type I (CRPS I) and to quantify their severity. DESIGN: Diagnostic signs and symptoms were recorded in patients suffering from CRPS I of one upper extremity for less than 1 year. Independent assessors measured (a) pain by using four visual analog scales (VAS) and the McGill Questionnaire list of adjectives (MPQ), (b) edema with a hand volumeter, (c) skin temperature with an infrared thermometer, and (d) active range of motion (AROM) with goniometers. SETTING: Two university hospitals. PATIENTS: Ninety-five women and 40 men with CRPS I of one upper extremity. RESULTS: Four signs and symptoms were diagnosed in 50 patients, and five in the remaining 85 patients. The mean score for present pain intensity was 31.5 mm and that for pain resulting from exertion of the affected extremity was 71.9 mm. A median of 11.5 words was chosen from the MPQ, with the highest number from its evaluative part. The difference in volume between both hands was 30.4 ml. The mean difference in temperature between the two hands was 0.78 degrees C dorsally and 0.66 degrees C palmarly. The largest decrease in mobility was seen in the wrist and fingers; the thumb was relatively less affected and the little finger relatively more affected than the other fingers. CONCLUSIONS: Bedside evaluation of CRPS I with Veldman's criteria was in good accord with psychometric or laboratory testing of these criteria.

Adult↗
PubMed1999

Objective and subjective assessments of temperature differences between the hands in reflex sympathetic dystrophy.

OBJECTIVE: A difference in temperature between the affected and normal extremity is one of the signs or symptoms of reflex sympathetic dystrophy (RSD). These temperature differences are scored anamnestically, by palpation, or by measurements. We investigated the relationship between objective and subjective differences in skin temperature between the hands. SUBJECTS AND DESIGN: Fifty-one patients with RSD of one upper extremity participated (mean age 55 years, range 18-80). In the first 16 we investigated the reliability of the visual analogue scale (VAS) for recording perceived differences in skin temperature. In the remaining 35 patients the relationship between the VAS and objective infrared radiometry of the hands was investigated. SETTING: Outpatients clinics of two university hospitals. RESULTS: The VAS was found to be reliable in terms of response stability. There was no significant correlation between the objective and subjective outcomes. CONCLUSIONS: There is lack of correspondence between objective and subjective temperature measurements, which may be due to a normal discrepancy between objective and perceived temperature, and/or to alterations in perception due to RSD.

Adolescent↗
PubMedDate not supplied

Reduction of enamel solubility by sodium monophosphate.

The preponderance of evidence indicates that sodium monofluorophosphate exerts a highly beneficial effect on dental caries incidence and enamel solubility. Optimal effects are obtained with a concentration of 4 X 10(3) ppm fluoride, by a four-minute application and by adjusting the pH to 4.0. The reaction of sodium monofluorophosphate with enamel is not temperature dependent. Sodium monofluorophosphate is significantly more protective than sodium fluoride in aqueous solutions at all equivalent fluoride concentrations and in pastes at concentrations exceeding 8 X 10(3) ppm fluoride.

Dental Enamel Solubility↗