We performed single fiber electromyography (SFEMG) in the superior rectus and levator palpebralis (SR-LP) muscles of 17 patients with pure ocular myasthenia gravis (MG) and 9 controls. Thirteen patients were also assessed with SFEMG in the orbicularis oculi (OO) muscle. All the MG patients but none of the control subjects showed abnormal SFEMG jitter in the SR-LP muscles. On the other hand, only 62% of the MG patients had abnormal SFEMG jitter in the OO muscle. The procedure was well tolerated by the patients, and complications were minor. We conclude that SFEMG of the SR-LP muscles is a safe and highly sensitive technique for the diagnosis of ocular MG.

Adult↗

PubMed1995

Scalp-recorded oscillatory potentials evoked by transient pattern-reversal visual stimulation in man.

Replicable oscillatory potentials, time-locked to pattern stimuli (9.0 degrees central; counterphase reversal at 2.13 Hz) were dissociated from conventional, broad-band VEPs recorded in healthy volunteers at occipital scalp locations by high-pass digital filtering at 17.0-20.0 Hz. Nine consecutive wavelets were identified with a 56.4 +/- 8.4 msec mean latency of the first replicable wavelet and mean peak-to-peak amplitude varying between 0.9 and 2.0 muV. The first 2 wavelets had significantly shorter latencies than wave N70 of unfiltered VEP, whereas the last 2 wavelets had longer latencies than N145. Latency and amplitude values varied as a function of contrast and spatial frequency of the stimulus, with shorter latencies and larger amplitudes at 60-90% contrast level and tuning of amplitude at 5.0 c/deg. All wavelets were correlated with wave P100 of unfiltered VEP, while a correlation with N70 of VEP was observed only for those wavelets with latencies in the range of wave P100. Two patients with documented brain lesions involving the visual system are described as examples of oscillatory responses occurring irrespective of filter bandpass and instead of the expected conventional VEP when the generation of these is interfered with by brain pathology. A substantial cortical contribution to the origin of the oscillatory response is conceivable. It is suggested that the oscillatory response to pattern-reversal stimulation reflects events in the visual system that are parallel to, and partly independent of, the conventional VEP, with potential application in research or for clinical purposes.

Adolescent↗

PubMed1995

Neuroendocrine cells in peripheral prostatic zone: age, prostatic intraepithelial neoplasia and latent cancer-related changes.

The neuroendocrine cells (NCs) in the peripheral prostatic zone of 32 patients without prostatic symptoms and with an average age of 61.4 +/- 6.7 (range 48-75) years were studied, and it was found that most are closed-type cells (95.8%) and that there is a gradual fall both in their total number and the number per square millimeter (p = 0.03) with advancing age. There were microscopic foci of high-grade prostatic intraepithelial neoplasia (PIN) in 59.3% of the patients and occult carcinomas in 28.1%, but no statistical relationship was found between these lesions and the number of NCs (p = 0.35 and p = 0.9, respectively). The gradual increase in NCs in the peripheral zone of normal prostates as of adolescence, reported in the literature, would appear to support a possible androgenic action on these cells. Our finding of a decrease in patients with foci of PIN and carcinoma from the fifth decade suggests that this decrease in NCs may make the prostate more susceptible to carcinogenic factors.

Adenocarcinoma↗

PubMed1995

Environmental urban lead exposure and blood lead levels in children of Mexico City.

Lead contamination is now a leading public health problem in Mexico. However, there are few data on the lead content of various environmental sources, and little is known about the contribution of these sources to the total lead exposure in the population of children residing in Mexico City. We conducted a cross-sectional study in a random sample of 200 children younger than 5 years of age who lived in one of two areas of Mexico City. Environmental samples of floor, window, and street dust, paint, soil, water, and glazed ceramics were obtained from the participants' households, as well as blood samples and dirt from the hands of the children. Blood lead levels ranged from 1 to 31 micrograms/dl with a mean of 9.9 micrograms/dl (SD 5.8 micrograms/dl). Forty-four percent of the children 18 months of age or older had blood lead levels exceeding 10 micrograms/dl. The lead content of environmental samples was low, except in glazed ceramic. The major predictors of blood lead levels were the lead content of the glazed ceramics used to prepare children's food, exposure to airborne lead due to vehicular emission, and the lead content of the dirt from the children's hands. We conclude that the major sources of lead exposure in Mexico City could be controlled by adequate public health programs to reinforce the use of unleaded gasoline and to encourage production and use of unleaded cookware instead of lead-glazed ceramics.

Adult↗

PubMed1995

Visual evoked potentials generator model derived from different spatial frequency stimuli of visual field regions and magnetic resonance imaging coordinates of V1, V2, V3 areas in man.

Visual evoked potentials (VEPs) to pattern reversal vertical bar stimuli were recorded from 24 scalp derivations (including zygomatic and inion) referenced to digitally linked earlobes in 50 controls. 1, 2 and 4 cpd patterns were presented as full field (FF) stimuli, on Upper Hemifields (UHF) and Lower Hemifields (LHF), upper and lower quadrants and with the occlusion of central and peripheral UHF and LHF. VEPs to octant stimuli were also recorded with 2 cpd patterns. N1, P1 and N2 components were recorded from posterior and inion derivations with FF stimuli, from posterior derivations with LHF stimuli, only from inion leads with UHF stimuli, from derivations ipsilateral to stimuli with quadrants and octants, and consistently from midline derivations only with lower quadrants. Polarity inverted sequences (iN1-iP1-iN2) were recorded from the other scalp derivations, with similar latency and spatial frequency sensitivity as N1-P1-N2. Single Equivalent Dipole (ED) calculations were performed on N1 and P1 recorded in the different stimulus conditions. Our findings contradict previous hypotheses on VEP generators and contradict the predictions of VEPs polarity and distribution based on the "cruciform model" of VEPs generators. In order to explain the distribution of VEPs to upper and lower half fields and to quadrant and octants, we propose a model based on the position of the medial and occipito-polar surface of visual cortex in man.

Adult↗

PubMed1995

Pulmonary arteriovenous fistula ruptured to pleural cavity in pregnancy.

Congenital pulmonary arteriovenous fistula is frequently associated with hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber disease). With the increased blood flow in pregnancy such fistulas enlarge, occasionally giving rise to haemothorax, which generally has a poor prognosis. A familial case is presented in which massive haemothorax required emergency thoracotomy in the 27th week of pregnancy.

Adult↗

PubMed1995

Choosing the best HMO.

Contrary to recent studies, the form of a health plan--whether it's a group-model or IPA-model HMO--is less important than quality, performance, and administrative efficiency.

Cost-Benefit Analysis↗

PubMed1995

Integrated delivery systems ... managed care organizations, hospitals, doctors, and insurers are developing new entities to compete for business.

Explore the source record for details and available documents.

Computer Communication Networks↗

PubMed1995

The interwined roles of primary care physicians and specialists.

Explore the source record for details and available documents.

Communication↗

PubMed1995

[Development of products for the elderly population: vitamin enriched pudding].

An instant dessert powder, pudding type was developed to be consumed at lunch or dinner time. The dessert was designed to be prepared in skim milk and meets the nutritional needs of elderly people. The dessert contains modified starch, carragenine, vegetal fat, sacharose. Each serving has been enriched with 30% of the daily vitamin requirement advised for adults over 51 years old. The optimized process was carried out according to the Karlsruhe test. Each serving consists of 22g powder prepared in proportion of 18% in skim milk. The optimized dessert powder was controlled by means of physical, chemical and microbiological analyses. The sensory quality was determined in the ready to eat product and the acceptability level was measured in a group of people selected according to the characteristics of the target population. The dessert powder contains 1.1% protein, 5.2% fats, 89.76% carbohidrates, and provides 409 Kcal/100g. Both the sensory and microbiological quality were good and the level of acceptance reached 98%.

Aged↗

PubMed1995

[Manufacture of a freeze dried stew for mountaineers].

The mountaineers use to eat at the evening dinner which ought to fulfil the following requirements: it should be nutritive and have an adequate composition, a small volume and should be light, keeping a good quality during a long period of time. Its preparation must be fast and easy, being well accepted by the group of mountaineers. A stew of common use in Chile based on meat and vegetables was elaborated, known as < >, a typical chilean stew. It was dehydrated by freeze-drying, a process based in the freezing and subsequent ice sublimation of the product, achieving a very high retention of both sensory and nutritional qualities. The final product corresponded to individual portions of 60g of Charquican which was vacuum-packed in a coextrude polyamide-polyethylene pack, which protects from the moisture and oxygen. It was used an outer packaging of plastic-coated aluminum foil, in order to protect him from the light. Controls of the optimized product indicate a 6,7% of humidity with an aw value of 0,26. The chemical composition is nutritionally adequate, with a 45.6% of carbohydrates, 5,0% of lipids and 29,5% of proteins. It presents a sensory quality with typical characteristics which ranged from good to very good. The microbiological quality meets the Standards of the Chilean Sanitary Regulation for Foods. The total plate count and the molds and yeasts count were below the proposed limits. The study of the Charquican s shelf life performed at environmental storage conditions (20-25 degrees C and 50-55 RH) showed that the microbiological quality is mantained without significant differences. The sensory quality presents a slight and gradual decrease until the average score fo 6,7 after 200 days storage. The evaluation with excursionists at the mountains, showed the excellent acceptability and the good reliability of the product.

Chile↗

PubMed1994

Structural dimorphism in the mammillary bodies of the rat.

Diverse structures of the CNS show sexual differences in the anatomical and functional organization. In particular, many dimorphic nuclei have been found in the hypothalamus: the preoptic area, suprachiasmatic nucleus and ventromedial hypothalamus. Our investigation has shown a statistically significant difference in relation to volume of the medial mammillary and left lateral nuclei, and the number of glial cells of the medial mammillary nucleus. The volume and glial cell population is greater in the male than in the female. Thus, the existence of dimorphic functions in which this structure could be involved are discussed herein.

Animals↗

PubMed1994

Extended cervical mediastinoscopy: prospective study of fifty cases.

To assess the usefulness of extended cervical mediastinoscopy (ECM) in the staging of bronchogenic carcinoma, an ECM was performed prospectively in 50 patients with bronchogenic carcinoma of the left lung. The ECM was used after evaluation of disease operability and computed tomographic findings, and was performed simultaneously with standard cervical mediastinoscopy. In ECM, using the same cervical incision as in a standard cervical mediastinoscopy, dissection is performed behind the anterior face of the sternum. The aortic arch is reached at the level of the origin of the innominate artery. The mediastinoscope is then passed by sliding it along the left anterolateral face of the aortic arch until it reaches the aortopulmonary window. Extended cervical mediastinoscopy was considered positive when a nodal biopsy result consistent with a neoformative process or direct invasion of the mediastinal structures was found. Four patients with positive standard cervical mediastinoscopy and negative ECM were excluded. A false negative ECM was defined as the presence of infiltrated adenopathies at the paraaortic level detected on postoperative histologic study. The ECM was positive in 5 patients in whom operation was contraindicated. Resectability in the remaining 41 patients was 97.6%. Postoperative pathologic study showed infiltrated adenopathy in 3 patients (2 subcarinal, 1 subaortic) accounting for 40 true negatives (the subcarinal group is inaccessible by ECM). This study suggests that ECM has outstanding specificity (100%), sensitivity of 83.3%, and a diagnostic accuracy of 97.8%. A positive predictive value of 100% and a negative predictive value of 97.5% were also identified by this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗