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Biomedical subjects

F Silva

Publications and source records attributed to F Silva.

At least 55 records · Page 3Linked to original sources
PubMed1987

Renal lesions in plasma cell dyscrasias: ultrastructural observations.

The renal biopsies from 47 patients with plasma cell dyscrasias were studied by light and electronmicroscopy, and by immunohistochemical methods. This report is primarily concerned with the ultrastructural features of 24 cases of Bence Jones cast nephropathy and of ten cases of light chain deposit disease. In Bence Jones cast nephropathy, crystals derived from light chain proteins were detected in the majority of cases within the casts or in tubular cells and appeared to be related to the "hard" and "fractured" appearance of the casts as well as to the presence of foreign body type giant cells, the latter probably being of monocyte-macrophage origin. In light chain deposit disease, linear deposits of light chain proteins (eight kappa and two lambda) were present in a subendothelial position along the glomerular basement membrane and along the outer aspect of the tubular basement membranes in all cases, quite often in the mesangial matrix, but much less commonly in the interstitium and in the wall of small arteries. The light and electronmicroscopic features of both Bence Jones cast nephropathy and light chain deposit disease can be considered diagnostic for plasma cell dyscrasia. The possible pathogenetic mechanisms of these two different forms of renal involvement are discussed briefly.

Bence Jones Protein↗
PubMed1984

In vivo reconstitution of ricin-like activity from its A and B chain subunits.

The capacity of highly purified preparations of ricin A and B chains to reconstitute ricin toxicity both in vitro and in vivo was studied. When the nontoxic A and B chain subunits were mixed and electrophoresed on sodium dodecyl sulphate-polyacrylamide gels (SDS-PAGE), reconstituted ricin was observed. The mixtures killed cells of the human Burkitt's lymphoma cell line Daudi in vitro and killed mice after i.v. injection. It was also shown that when mice were injected with one ricin subunit followed by administration of the complementary polypeptide up to 8 hr later, they died with lesions similar to those of ricin-induced death. This observation suggests that A and B chains recombine either in the serum or on the surface of cells. The rate of clearance of A and B chains from the blood of rats indicated that sufficient concentrations of either chain were present in the circulation 8 hr after injection to account for the observed toxicity. The above studies therefore suggest that the subunits of ricin have a very high affinity for each other and are capable of reconstituting biologically active ricin in vitro and in injected mice.

Animals↗
PubMed1982

Gastrin-secreting tumor of the duodenum (G-cell apudoma) associated with secondary biliary cirrhosis.

A middle-aged woman with evidence of chronic cholestasis of several years and no previous abdominal surgery was initially thought to have primary biliary cirrhosis. Clinical evaluation disclosed a well-developed secondary biliary cirrhosis apparently caused by extrahepatic obstruction due to a 1 X 2 cm neoplasm of the periampullary duodenum. Electron microscopy and immunofluorescent studies showed the neoplasm to be a G-cell adenoma. Wide local excision has resolved the biliary obstruction. Bening or slow-growing duodenal tumors, if they involve the ampulla of Vater, may produce prolonged partial extrahepatic obstruction and secondary biliary cirrhosis.

Adult↗
PubMed1981

Acute interstitial nephritis due to amoxicillin therapy.

Acute interstitial nephritis (AIN) has been reported in association with therapy with a number of drugs. We report a patient who developed drug-related AIN while receiving intravenous amoxicillin therapy. The patient developed rash, secondary temperature elevation, and eosinophilia in association with nonoliguric renal failure. Renal biopsy showed evidence for AIN and the renal failure was responsive to corticosteroid therapy. AIN may occur in patients receiving any drug of the penicillin class. This reversible form of acute renal failure must not be overlooked in patients with other forms of renal disease.

Acute Disease↗
PubMed1979

Pulmonary metastases (with admixed epithelial elements) from smooth muscle neoplasms. Report of nine cases, including three males.

This study pertains to an entity characterized by the presence of multiple intrapulmonary nodules, which consist of an admixture of bundles of well-differentiated smooth muscle cells and epithelial-lined spaces. These lesions have been frequently interpreted as a variant of hamartomas. However, in this review of the literature, and careful analysis of nine cases of this entity, we concluded that they should be considered metastases from smooth muscle tumors which incorporate some structures of mature lung parenchyma as they slowly expand. We affirm that the designation "fibroeliomyomatous hamartoma" should be discarded. Our cases occurred in six female and three male patients. In all but one female the primary source for lung metastases was uterus, while the male patients had primary lesions in the saphenous vein, diaphragm, and soft tissues. These lung lesions increase in size and number and are potentially fatal, though this may take many years. Even though the smooth muscle cells of the lung nodules appear bland on light microscopy, we were always able to demonstrate mitotic activity; electron microscopy indicated immaturity of the cells. For these reasons, we believe the tumors to represent metastatic leiomyosarcomas.

Adult↗
PubMed1978

Renal lesions in chronic pancreatitis.

Many patients with chronic pancreatitis (CP), even in the absence of intrinsic renal disease, are found to have abnormal urine, with persistent proteinuria, cylindruria, microhematuria and leukocyturia. The kidneys of 12 necropsy cases with CP showed mild to moderate arterial and arteriolar nephrosclerosis and no other significant changes. Renal biopsies were performed in 10 patients with CP without evidence of systemic disease or intrinsic renal disease, but with persistent urinary abnormalities. By light microscopy, mild arterial and arteriolar nephrosclerosis was present in 5 instances. In 1 patient, evidence of the reparative phase of acute tubular necrosis was noted. In 5 biopsies, electron microscopy revealed minimal to mild increase in mesangial matrix. Mild thickening of the glomerular basement membrane (GBM) was found in three instances but there was no clear-cut evidence of diabetic glomerulosclerosis. The presence of subendothelial electron-lucent material in 3 cases suggests the possibility of previous subclinical episodes of intravascular coagulation. The most consistent finding was the presence of lipid material in the cytoplasm of glomerular and tubular cells. The renal lesions associated with CP are mild, nonspecific and nonprogressive. Various pathogenetic factors can be invoked to account for their presence and for the urinary abnormalities found in patients with CP.

Adolescent↗
PubMed1978

Acute interstitial nephritis associated with carbenicillin therapy.

Although acute interstitial nephritis has been documented during therapy with many antibiotics of the penicillin class, it has not previously been reported in association with carbenicillin therapy. We report here the case of a patient who developed the characteristic clinical features of this form of injury while receiving prolonged large doses of carbenicillin. Histologic examination confirmed the presence of a striking interstitial nephritis. Carbenicillin should be considered a potential cause of renal damage in patients who develop rash, eosinophilia, and microscopic hematuria in association with deterioration of renal function.

Acute Disease↗
PubMedDate not supplied

Colombian study to assess the use of noninvasive determination of the endothelium-mediated vasodilation (CANDEV) II: does location of the occlusion device affects the accuracy of the diagnosis?

Endothelial dysfunction (ED), which is often evaluated by flow-mediated vasodilation (FMV) in the brachial artery, has been postulated as a predictor of cardiac events. Although the upper and forearm location of the occlusion device have been used for FMV evaluation, currently there is no consensus whether they provide the same information. The main goal of this study was to evaluate if both techniques have the same accuracy to differentiate subjects with and without cardiovascular risk factors (CRFs). A cross-sectional study in 124 subjects was performed. The volunteers were divided in two groups: 62 subjects (20 women and 42 men) with at least one CRF and 62 (20 women and 42 men) healthy subjects without CRFs. FMV measurements using the cuff in the upper arm and forearm with intervals of 30 min were taken. In all subjects, %FMV with the cuff located in the upper arm was 10.13 +/- 4.5 and 9.8 +/- 4.1 with the cuff located below the elbow. In healthy subjects without CRFs the %FMV in the upper arm was 12.19 +/- 4.0 versus 12.31 +/- 3.4 in the upper forearm, in CRF subjects it was 8.08 +/- 4.0 vs 7.29 +/- 3.2., respectively. FMV was not affected by the location of the cuff in maintaining the test ability and accuracy to differentiate subjects with and without CRFs.

Adult↗
PubMedDate not supplied

Gastrointestinal stromal tumors: a "benign" tumor with hepatic metastasis after 11 years.

Gastrointestinal stromal tumors (GIST) constitue the largest category of primary non-epithelial neoplasms of the stomach and small bowel. They are characterized by a remarkable cellular variability and their malignant potential is sometimes difficult to predict. Very recent studies, using mitotic count and tumor size as the best determinants of biological behavior, divide GISTs into three groups: benign, borderline and malignant tumors. We report on a male patient who underwent a right hepatectomy for a large metastasis 11 years after the surgical treatment of an antral-pyloric gastric neoplasm, histologically defined as leiomyoblastoma and with clinical, morphological and immunohistochemical features of benignity (low mitotic count, tumor size < 5 cm, low cellular proliferation index). Histological and immunohistochemical analysis of the hepatic metastasis showed the cellular proliferation index (Ki-67) to be positive in 25% of neoplastic cells, as opposed to the primary gastric tumor in which Ki-67 was positive in only 5% of neoplastic cells. In conclusion, although modern immunohistochemical techniques are now available to obtain useful prognostic information, the malignant potential of GISTs is sometimes difficult to predict: neoplasms clinically and histologically defined as benign could metastasize a long time after oncologically correct surgical treatment. Therefore, benign GISTs also require consistent, long-term follow-up.

Hepatectomy↗
PubMedDate not supplied

[Pulmonary arterio-venous fistula: a clinical report].

A 44 years old female was admitted with previous history of several cerebral vascular accident (CVA). A transthoracic echocardiogram showed a patent foramen ovale (PFO) that was closed, under extracorporeal circulation. The patient remained free of symptoms for ten years. In the year 2003 she was admitted to our hospital with paresthesias of the left arm. The clinical evaluation led to the diagnosis of arteriovenous fistula (AVF) of the lung. In November 2003, the patient underwent right inferior lobectomy. This is a rare association of PFO with AVF fistula of the lung with a delayed diagnosis. The differential diagnosis, the surgical treatment and the most frequent complications of this pathology are reported and discussed.

Adult↗