Removal of chlorothalonil, methyl parathion and methamidophos from water by the Fenton reaction.

The efficiency of a dark Fenton system (H2O2/Fe2+) to remove chlorothalonil from water, alone and in the presence of the organophosphorous pesticides methyl parathion and methamidophos, was evaluated. Here we show that the process is rapid and efficient. Nearly complete degradation of chlorothalonil and methyl parathion (98%) was observed in less than 10 min whereas methamidophos showed similar levels of efficiency only after 40 to 90 min. Formulating agents did not appear to impair the degradation of active ingredients. Interactions during the degradation of mixtures of the three pesticides only appeared to affect methamidophos degradation.

The effects of muscle fatigue on bone strain.

There is anecdotal evidence that bone strains may increase to the point that bone becomes susceptible to rapid failure when muscles become fatigued. To determine whether neuromuscular response could be a factor in accelerating bone failure, we tested the hypothesis that muscle fatigue causes a significant increase in peak principal and shear strains in bone. Ten adult foxhounds were subjected to rigorous exercise that caused muscular fatigue while myoelectrical activity of the quadriceps and hamstrings and strain on the distal tibia were monitored simultaneously. Ground reaction forces on the dog hindlimbs were measured before and after strain gauges had been applied to the tibia. The data show a significant shift to lower median myoelectrical frequencies in the quadriceps, indicating muscular fatigue, following the 20 min exercise period. In conjunction with this shift, peak principal and shear strains increased on both compressive and tensile cortices of the tibia and shear strain on the tensile cortex increased significantly (P = 0.02). The largest changes were along the anterior and anterolateral surfaces of the tibia, where peak principal strain increased by an average of 26-35% following muscular fatigue. The cross-sectional strain distribution was calculated at the gauge site at peak strain at the beginning of the exercise period and at peak strain after 20 min of exercise. These data show a change in strain distribution when muscle becomes fatigued. Strains on the posterior cortex of the bone showed the greatest change. Correlation analysis demonstrated a significant inverse association between median myoelectrical frequency and bone strain after 20 min of exercise (Spearman r2 = 1.00; P = 0.05). These data show that muscle fatigue may be associated with increased bone strain.

Isometric exercises and a simple appliance for temporomandibular joint dysfunction: a case report.

This case report presents a treatment approach for a patient with temporomandibular joint (TMJ) dysfunction signs and symptoms. Temporomandibular joint pain, jaw clicking and locking, and postural abnormalities were treated with gentle isometric (static) exercises, coordination exercises, and an easily fitted and readily available appliance. After treatment, the patient showed reduced TMJ pain, no jaw locking, and improved TMJ mobility. The patient also showed improved postural awareness. The results of treatment and the relatively minor cost of the appliance make the sharing of this case study potentially worthwhile for those clinicians treating patients with TMJ dysfunction.

Electromyographic and dynamometric characteristics of female pelvic-floor musculature.

The purpose of this study was to determine whether differences existed on dynamometer recordings of muscle strength and electromyographic activity of the pelvic floor in 5 pregnant and 10 nonpregnant women. Pelvic-floor musculature strength measurements, using a perineometer, showed no significant differences between groups. All subjects could hold maximal voluntary contractions for three seconds, but pelvic-floor strength measurements decreased rapidly beyond three seconds. Integrated electromyographic recordings failed to show significant differences between groups. A periodicity of integrated electromyographic activity was observed in both pregnant and nonpregnant subjects. Great variability in the amount of integrated electromyographic activity was observed among both groups during maximal voluntary contractions. The practice of requesting that individuals with pelvic-floor dysfunction hold maximal voluntary contractions longer than three seconds may not be efficacious. Electromyographic measures must be complemented by strength measures for adequate evaluation and treatment of pelvic-floor dysfunction.

[Myocardial infarct without pathologic Q waves]. / Infarto del miocardio sin ondas Q patológicas.

Neither the presence nor the absence of pathological Q waves are related to the transmural or subendocardial localization of an acute myocardial infarction. The prognosis of an acute myocardial infarction without pathological Q waves is controversial. We studied 23 hospitalized patients with prolonged, typical chest pain, enzymatic elevation, an EKG without pathological Q waves but with changes in ventricular repolarization and a positive scintigraphy with radioactive pyrophosphates. The patients were classified in two groups according to the pattern of pyrophosphate uptake; group A had grade 2+ focal uptake (N = 13) and group B with grade 2+ diffuse uptake (N = 10). The level of serum glutamic transaminase was significantly greater in group A as compared to group B (p less than 0.05). However, levels of creatine kinase and lactic dehydrogenase were no different. The clinical hospital course was similar in both groups. Eleven patients were followed by 31.7 months: 30.4% had chronic angina, one underwent coronary bypass surgery, another suffered a recurrent myocardial infarction and there were no deaths. The diagnosis of acute myocardial infarction should be suspected in patients with prolonged angor pectoris, electrocardiographic changes in ventricular repolarization, increased enzymatic levels and a positive scintigraphy with a grade 2+ diffuse myocardial uptake of Tc 99m pyrophosphates. The diagnosis is certain if the uptake has a focal distribution.

[10 years of nuclear cardiology. (I). Clinical development and technological progress in nuclear medicine at the Ignacio Chávez National Cardiological Institute]. / Diez años de cardiología nuclear. (I). Evolución asistencial y progreso tecnológico de la medicina nuclear en el Instituto Nacional de Cardiología "Ignacio Chávez".

The department of nuclear medicine of the Instituto Nacional de Cardiología started at the right moment (June 2, 1977), when the first cardiological procedures were developed. Unfortunately, it coincided in time with the beginning of the financial crisis. The higher costs of nuclear medicine instruments and operationsdid not allow the evolution of the department according to the original project, as nuclear cardiology demands special tracers and instrumentation, which are expensive and only available abroad. To solve these problems, we planned the creation of our own technology. We created a laboratory for radiopharmacy to elaborate lyophylized ingredients for the "cold" kits for instant labeling with 99Tcm of several tracers. With this, we achieved a substantial decrease in the operating costs, with total independence of commercial firms, and the future of the department was assured. In the field of instrumentation, a new system for tomodensitometric imaging of the thorax has been created by using two external gamma sources 99Tcm, and a digital system for image display and analysis was designed, built and programmed. This system, allowed the development of the quantitative technique of nuclear cardiology. We expect the software menu to be finished within this year. The transit from general nuclear medicine to nuclear cardiology has been slow in this Institute. During the first 8 years, the cardiological studies represented 10.8% of all in vivo studies; this figure increased to 37.8% in 1986. However, the increasing demand of cardiological studies tends to displace other in vivo studies due to oversaturation of the gamma-camera and the digital system. It can be concluded that the evolution of nuclear cardiology has been slow in this Institute, but represents a factual progress based on the creation of a technological substructure with internal resources.

[Use of technetium 99m radio-angiocardiography in the identification of myxoma of the right atrium. Presentation of 2 cases]. / Uso de la radioangiocardiografía con tecnesio-99m en la identificación del mixoma de la aurícula derecha. Presentación de dos casos.

A right atrial myxoma was identified in two patients with radio-angiocardiography-99m Tc. Tumor is identified as a persistent photon-deficient region in both first-pass and equilibrium images. In addition there is an abnormal accumulation and sluggish disappearance of the radionuclide from the right atrium. Even though sensitivity of the procedure should be confirmed, it is a helpful non-invasive technique of great value in the diagnosis oF right atrial tumors.

The role of physical agents in the treatment of spine pain.

Transcutaneous electrical nerve stimulation (TENS) and electroacupuncture are effective agents in the management of spine pain. Ultrasound and shortwave therapy are often used, but the demonstrated effectiveness of these physical agents in the treatment of spine pain is questionable. Pain relief is the major reason for the use of physical agents. As the pain is controlled, the patient is better able to carry out a home program, tolerate traction, or relax sufficiently to allow mobilization of the spine. Physical agents alone have no long-range value.