Biomedical subjects
Publications and source records attributed to M Machado.
Magnetic resonance imaging of the brain and spinal cord were carried out for seventeen consecutive patients with HTLV-1 associated myelopathy (HAM). Eight patients had brain abnormalities and four had decreased thoracic spinal cord diameter. Brain lesions were mostly located in subcortical and periventricular areas. Our data suggest that diffuse central nervous system lesions are present in patients with HAM.
The chronic inflammatory response to wear particles from orthopaedic joint implants is believed to cause osteolysis and to contribute to prosthetic loosening. Previous in vitro experiments have demonstrated that particulate debris from joint implants causes cells in culture to release products that have been implicated in this pathological bone resorption. The purpose of the current study was to investigate the in vivo features of this complex process in patients who had had a total hip replacement. Membraneous tissue was obtained from the cement-bone interface of ten polyethylene acetabular components that had been revised for aseptic loosening in ten patients. The immunoperoxidase technique, which involves the use of specific antibodies for each cell type, showed that macrophages were the predominant cellular constituents but also that fibroblasts, many of which were not identified on plain histological study, were present and were actively producing collagen. T lymphocytes were present variably, but they generally composed less than 10 percent of the cells. Particulate debris (polyethylene, methylmethacrylate, and metal) was present in all membrane specimens but was intracellular only in macrophages and multinucleated giant cells. 35S-labeled nucleic-acid probes, complementary to human interleukin-1-beta and to platelet-derived growth-factor-2 messenger RNA (mRNA), were hybridized with serial tissue sections. Hybridization demonstrated interleukin-1-beta mRNA predominantly in macrophages, and not in fibroblasts or in T lymphocytes to any major extent. In contrast, immunolocalization demonstrated interleukin-1-beta protein on both macrophages and fibroblasts, suggesting that macrophages release interleukin-1-beta, which then binds to both fibroblasts and macrophages. Platelet-derived growth-factor transcripts were found in both macrophages and fibroblasts.
Although subclavian vein stenosis is a well-known complication of haemodialysis subclavian catheters, little is known about its causes. Catheter-related infection is the most common complication of this technique, but its role in the genesis of late subclavian stenosis has not been established. We retrospectively analysed 80 subclavian catheterizations in a total of 54 chronic haemodialysis patients from a single center. Sixteen catheters had to be removed because of a well documented catheter-related infection: three catheter-related sepsis (2 with ipsilateral phlebitis), seven isolated fever with catheter tip colonization which disappeared after catheter removal, and six exit-site discharge with positive culture. For comparison we matched 14 contemporaneous catheters which were electively removed without evidence of infection and with a negative culture of the catheter tip. A venogram of the ipsilateral arm was performed in all the cases after more than 6 months of catheter removal. Both groups were remarkably similar with respect to age, sex, side of insertion, number of inserted catheters, time of indwelling, and time elapsed from removal to venography. Definite subclavian stenosis was three times more common among patients with previous catheter-related infection (75% versus 28%; P < 0.01). Interestingly, both patients with ipsilateral phlebitis showed total occlusion of the subclavian vein. Although all diabetic patients of the study (n = 6) suffered a catheter-related infection, the incidence of late subclavian stenosis was not more common than in non-diabetic infected patients. In summary, subclavian haemodialysis catheter-related infection is a major risk factor for the development of late subclavian vein stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)
The synthesis and localization of endothelin-1 were studied in human and rabbit bladder. In addition, the effects of endothelin-1 on smooth muscle tone and cholinergic neurotransmission were investigated in rabbit bladder. Endothelin-like immunoreactivity was localized in the transitional epithelium, serosal mesothelium, and vascular endothelium; smooth muscle of the bladder (non-vascular) and that of blood vessels; and fibroblasts. With in situ hybridization, transcripts of endothelin messenger ribonucleic acid (mRNA) were localized with the same cellular distribution as endothelin-like immunoreactivity, in bladder tissue. Northern blot analysis of bladder RNA confirmed the expression of preproendothelin-1 mRNA. Rabbit bladder strips in organ chambers contracted when exposed to endothelin-1 and this response was partially attenuated by calcium channel blockers or by removal of extracellular calcium. Transmural electrical stimulation of rabbit bladder strips elicited contractions that were greatly reduced by atropine. The remaining atropine resistant component was blocked by alpha, beta-methylene ATP, which desensitizes purinergic receptors. Endothelin-1 caused a small but consistent attenuation of the atropine sensitive component of the neurogenic contraction, while it had no effect on the atropine resistant component. The localization of endothelin synthesis in epithelia, smooth muscle, and fibroblasts suggests that endothelin may act as an autocrine hormone in the regulation of the bladder wall structure and smooth muscle tone. In addition, endothelin-1 may regulate cholinergic neurotransmission by a paracrine mechanism.
We studied 18 patients, 9 women and 9 men, ranging in age from 18 to 76 years. The main symptom was hemoptysis and the underlying pathology was tuberculosis, actinomycosis, lung cancer, metastatic carcinoma and systemic lupus. Nonsurgical patients, with recurrent hemoptysis or massive bleeding were selected. The embolization substances were spongostan, avitene (R) and PVA; they all produce temporary as well as persistent hemostasis. The procedure was successful in 16 patients. In two patients the embolization was not performed, one for technical reasons and the other because the vessel to be treated was the source of an anterior spinal artery. It is considered that the endovascular treatment constitutes an alternative for hemoptysis, even during the acute period, mainly in the management of nonsurgical patients.
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To examine previous work carried out at a single center, i.e., France, on the pathologic features of chronic pancreatitis and to examine geographic differences, 359 cases of chronic pancreatitis from five centers were studied pathologically and the results analyzed according to appropriate statistical methods. It was found that it was easy to separate chronic calcifying pancreatitis from obstructive pancreatitis occurring distal to obstruction to the pancreatic duct by pathological means. On the other hand, geographic differences between France, Italy, Brazil, and South Africa, although present, were not sufficient for identification of a specific profile for each of the countries studied, and it was found that the minor differences were probably dependent on environmental rather than racial factors.
Advances in chemotherapy have increased the indications for insertion of cerebrospinal fluid (CSF) reservoirs in the treatment of both primary and secondary central nervous system neoplasia. There have been no recent evaluations of the current indications and complications of this procedure in a general neurooncology practice. We undertook a retrospective review of our total experience of 60 patients who were implanted with CSF reservoirs between November 1977 and October 1983. The mean age of those implanted was 38 years (range, 22 months to 79 years). The reasons for insertion were: drug instillation, 35 cases (58.3%); drug level monitoring, 15 cases (25.0%); intermittent tumor cyst drainage, 6 cases (15.0%); and syrinx drainage, 1 case (1.6%). Drug level monitoring was most often done in conjunction with specific experimental chemotherapy protocols. There were no complications after primary insertion, but 9 of 60 reservoirs (15%) required revision for technical failure. Revision was much more likely to occur in the presence of an intracranial mass lesion (7 of 34, or 20.5%). The revision rate in cases of meningeal carcinomatosis was only 7.6% (2 of 26). Patients requiring revision included 5 with glioblastoma, 2 with metastatic tumors, and 2 with meningeal carcinomatosis. Four of the 9 patients requiring revisions developed complications (44%). There were three infections with positive CSF cultures and one subdural hematoma. Infected patients included those with multiple craniotomies, prior cranial irradiation, or some form of chemotherapy. We conclude that primary insertion of a CSF reservoir in a patient with neoplastic involvement of the central nervous system is extremely safe, that technical failure tends to occur in the presence of mass lesions, and that the complication rate of repeated insertion is quite high.
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Based on the authors' experience, this paper discusses a series of problems during the implementation of so-called Indigenous Health Districts (DSEI) in Brazil, related to organization of health services provision as viewed by both health professionals and anthropologists. The authors report on the Health District model's underlying concepts and present the different approaches used to implement the DSEI. The authors' experience refers to the Rio Negro area - in the northwestern Amazon, representing 10% of Brazil's total indigenous population - and the Brazilian Northeast, specifically the State of Pernambuco, with an indigenous population estimated at 20,000.
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PURPOSE: The purpose of this study was to evaluate the interfacial micromorphology of direct esthetic restorations bonded to primary or permanent tooth dentin with a self-etching primer adhesive system. METHODS: Superficial dentin at the occlusal surface of 15 primary and 15 permanent molars was exposed with a carbide bur. Prompt-L-Pop was applied in one half of each surface. A control bonding system, Single Bond or Vitremer Primer, was used in the other half Teeth were restored either with a composite resin (Filtek Z250), a compomer (Hytac), or a resin-modified glass ionomer (Vitremer). Twenty-five scanning electron microscope fields from 5 teeth were evaluated blindly by two investigators for each condition. RESULTS: In this study, a significant difference in quality of the interfacial seal was not observed when restorations performed in primary teeth were compared to restorations in permanent teeth. Interfacial gaps were observed in most restorations bonded with Prompt-L-Pop and restored with Filtek Z250 (9/10), Hytac (9/10), or Vitremer (5/10). No interfacial gaps were observed in teeth bonded with Single Bond and restored with Filtek Z250 (0/10) or Hytac (0/10), while all teeth bonded with Vitremer Primer and restored with Vitremer presented gaps (10/10). To understand the reason for the interfacial gaps observed with Prompt-L-Pop, we examined if this system generated a hybrid layer at the dentin/restorative material interface. All surfaces bonded with Single Bond and restored with Filtek Z250 or Hytac presented a visible hybrid layer. In contrast, 0/10 (Z250) and only 3/10 (Hytac) restorations bonded with Prompt-L-Pop showed signs of a hybrid layer. CONCLUSION: The self-etching primer adhesive system Prompt-L-Pop failed to generate sealed interfaces consistently between the dentin of primary and permanent teeth and the composite resin or the compomer evaluated in this study.
BACKGROUND/AIMS: Massive ascites and pleural effusions are uncommon but well-documented complications of chronic pancreatitis. The present study reviews the results of surgical management of pancreatic ascites and pleural effusions of pancreatic origin. PATIENTS AND MATERIALS: From forty-nine patients with chronic pancreatitis presenting with ascites and/or pleural effusion of pancreatic origin, 31 were surgically treated. RESULTS: Nineteen had ascites only, ten pleural effusions and two presented with both conditions. Diagnosis of the internal pancreatic fistula was based on the findings of high amylase levels and elevated albumin content of the peritoneal and pleural exudates. Failure of medical therapy was the indication of surgical treatment in all patients. Thirteen were submitted to internal pancreatic drainage, 17 to external drainage and one to distal pancreatic resection. Eight of 17 externally drained patients were reoperated for intraperitoneal abscesses (2), infected pseudocyst (1), pain recurrence (3) and pancreatic fistula (2); whereas reoperation occurred in only one of the 13 patients submitted to internal drainage (p < 0.05). CONCLUSIONS: Internal pancreatic drainage was the ideal surgical treatment for patients with pancreatic ascites and/or pleural effusion that did not respond to medical treatment. When this was not feasible external drainage was successfully used as an alternative to pancreatic resection.
Total parenteral nutrition with lipids is a well-accepted modality of metabolic support in seriously ill trauma patients. Intolerance to lipid administration is unusual when dosage limits are not exceeded, and few hematologic disturbances have been recorded with modern fat emulsions. In the course of intravenous alimentation of six adults admitted for traumatic lesions, eosinophilia with or without leukocytopenia was noticed after periods of four days to five weeks. Principal clinical events and hematologic derangements were documented in this population. Sepsis was not always present in the patients by the time of the complication, and in those that did require antibiotics and other drugs, the prescription remained unchanged along the episode. Discontinuation of the nutritional regimen with lipids was followed by normalization of the hematologic profile, suggesting that an acute or sub-acute allergic reaction was responsible. The appearance of skin rash in two occasions reinforces this hypothesis, and the possibility of hemophagocytosis merits consideration in two of the cases who displayed reversible acute leukocytopenia. It is concluded that blood cell aberrations are possible during intravenous feeding with lipids in trauma subjects, but tend to respond to suppression of the lipid-containing nutritional prescription.