Inhibitory role of diazepam on autoimmune inflammation in rats with experimental autoimmune encephalomyelitis.

Glutamate and GABA are the main excitatory and inhibitory neurotransmitters in the CNS, and both may be involved in the neuronal dysfunction in neurodegenerative conditions. We have recently found that glutamate release was decreased in isolated synaptosomes from the rat cerebral cortex during the development of experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis. In contrast to control animals where GABA induced a decrease in the evoked glutamate release, which was abolished by picrotoxin (a GABA(A) antagonist), synaptosomes from EAE rats showed a loss in the inhibition of the glutamate release mediated by GABA with a concomitant diminution of the flunitrazepam-sensitive GABA(A) receptor density. We have presently further evaluated the relevance of the GABAergic system in EAE by treating rats challenged for the disease with the GABA agonist diazepam. Administration of diazepam during 6 days starting at day 6 or 11 after EAE active induction led to a marked decrease of the disease incidence and histological signs associated with the disease. Cellular reactivity and antibody responses against the encephalitogenic myelin basic protein were also diminished. Beyond the effects of diazepam on the autoimmune, inflammatory response, we report also a positive effect on neurotransmission. Treatment with diazepam inhibited the previously described reduction in glutamate release in the frontal cortex synaptosomes from EAE animals. These data suggest that an endogenous inhibitory GABAergic system within the immune system is involved in the diazepam effect on EAE and indicate that increasing GABAergic activity potently ameliorates EAE.

Metal-backed and all-polyethylene tibial components in total knee replacement.

One hundred seventy-five patients with 243 consecutive primary Press Fit Condylar cruciate-substituting total knee replacements were evaluated at a mean of 5.5 years. One hundred thirteen knees had modular metal-backed tibial components and 130 had all-polyethylene tibial components. The mean knee score and functional score for the patients with unrevised components was not significantly different. The incidence of osteolysis and synovitis was higher in patients in the modular metal-backed tibia group (5%; five patients, six knees). No patients in the all-polyethylene tibia group had osteolysis or synovitis. Five revision operations were necessary: four for osteolytic defects and one for synovitis, all in patients in the modular metal-backed tibia group. All of the retrieved polyethylene inserts had evident backside wear. The best case rate of survival of the all-polyethylene tibial components was 96%+/-0.8% at 7 years and for the modular metal-backed components it was 75%+/-10% at 7 years. Metal backing and modularity were added to the Press Fit Condylar total knee replacement design to improve fixation durability. However, the superiority of the modular metal-backed implants remains in question.

[Endoscopic polypectomy of the upper digestive tract]. / Polipectomía endoscópica del tracto digestivo superior.

From 1985 to 1987 we performed 82 endoscopic polipectomies in 80 patients. In this paper we refer the technics, epidemiological data and macro and microscopical findings of the resected specimens. Two patients with gastric cancer were treated in this way, these patients had formal surgical contraindication. In two patients in whom the endoscopic biopsies could not render a definitive diagnosis (cancer or atypical epithelium), the study of the resected tumor permitted the diagnosis of atypical epithelium, so two gastrectomies were avoided. Among our resected lesions we found 55 of inflammatory type, 6 adenomas and 7 atypical epithelium. We consider that this is a useful method for the diagnosis and treatment of some elevated lesions. Although this is not the treatment of choice for the elevated early cancer, it could be used to treat cancerous tumors in patients with high surgical risk.

[Comparison of the postmortem anatomical study and bidimensional echocardiography in myocardial infarction]. / Comparación del estudio anatómico postmortem y la ecocardiografía bidimensional en el infarto del miocardio.

We studied 10 patients between the ages of 30 and 69 years, all of whom had suffered myocardial infarction (MI) at least 6 months before they died. Two-dimensional echocardiography (2-D E) and catheterism were done no more than 15 days before death. The location and extension of MI were compared to the segmentary mobility (SM), end diastolic wall thickness (EDWT) and percentage of systolic wall thickening (PSWT) determined by 2-D E, in the 15 segments of the left ventricular wall. We also compared 2-D E and coronariographic findings. There was a good correlation between the location (P less than 0.01) and extension (P less than 0.05) of the necrotic area dyssynergy, specially when the MI was transmural. The postmortem measurement of the wall thickness in each one of the segments had also good correlation with the EDWT as measured with 2-D E (r = 0.926). The EDWT was less in the necrotic segments (8.8 +/- 1.8 mm) than in non affected segments (14.1 +/- 1.9 mm) and this difference was significant (P less than 0.05). The wall was thinnest in segment affected by transmural necrosis. The PSWT was significantly less (P less than 0.01) in necrotic segments (12.1 +/- 3%) than in segments without necrosis (24.1 +/- 4.3%). The alteration of SM correlated with coronary obstructions greater than 75%, specially when it was associated with necrosis. The EDWT was less in necrotic segments with important coronary artery obstruction than in those without necrosis even though vascular narrowing was marked (P less than 0.01). The PSWT was also less in the areas with necrosis when coronary obstruction was severe as well as moderate (11.3 +/- 2.3%) than in segments with coronary obstruction but without necrosis (22.3 +/- 4.2%) and even less than that obtained in cases with neither coronary artery obstruction nor necrotic area (30.1 +/- 2.2%) and the difference is statistically significant (P less than 0.01). The segmentary measurement by 2-D E of the EDWT and the PSWT are useful for recognizing areas with necrosis and differentiating it from ischemic areas of left ventricle in coronary artery disease.

Dermatofibrosarcoma protuberans.

In view of the important clinicopathologic, evolutional, and ultrastructural characteristics of dermatofibrosarcoma Protuberans, a review was made of 30 patients seen during the last 25 years in Colombia's Instituto Nacional de Cancerologia. The incidence is low, accounting for 0.06% of all malignant tumors and 1.17% of all soft-parts sarcomas. The series comprises 19 women and 11 men, with the highest incidence found between ages of 30 and 50 years, although the study includes two children, ages 8 and 13. The chest was the most common site. Forty percent of the lesions were multinodular, and 23.3% showed ulceration. Histologic appearance is characterized in all cases by fusiform cells arranged like spokes around an empty hub. The fibroblastic origin was ascertained by electron-microscopic studies. The treatment used was broad surgical excision, removing tissue down to the aponeurosis to avoid recurrence.