Search PubMed⌕ Search

Biomedical subjects

L A Moura

Publications and source records attributed to L A Moura.

At least 19 recordsLinked to original sources
PubMed2007

Multiscale representation for automatic identification of structures in medical images.

The identification of structures is a key step in several applications of medical imaging. In this work we propose a method for the identification of structures using a multiscale approach with inclusion of a priori information about the searched objects. After describing the image structures in the multiscale representation, a matching step determines which structure most likely corresponds to the target. Patterns are generated by previous application of the method to a set of images. We present a prototype for identifying structures in 2D images. A set of experiments was carried out to evaluate the prototype leading to encouraging results.

Humans↗
PubMed2004

Monitoring anti-HLA Class I IgG antibodies in renal transplant recipients.

Anti-HLA class I IgG antibodies play an important role in hyperacute rejection but the significance of its de novo appearance or increase in levels during the posttransplant period remains controversial. The purpose of this study was to determine the correlation between the anti-HLA class I IgG antibodies and posttransplant events during the first 4 months after renal transplantation. From 200 renal allograft recipients, 549 serum samples were retrospectively evaluated. Patients who experienced graft dysfunction confirmed by biopsy had three serum samples tested: before, during (within 24 hours), and after the event. The presence of anti-HLA antibodies was observed in recipients with chronic allograft nephropathy (60%); acute rejection (clinical criteria without biopsy 57.1%); rejection types IIA (7.1%), IIB (40%), and III (50%); borderline changes (42.8%); acute tubular necrosis (34.4%); infarction (25%); and no rejection (12.5%). We observed a high incidence of anti-HLA class I IgG antibodies during acute tubular necrosis, borderline changes, acute rejection types IIB and III, and chronic allograft nephropathy.

Acute Disease↗
PubMed2004

Expression of cyclooxygenases during renal allograft rejection.

The aim of this work was to determine the expression of cyclooxygenases (COX-1 and COX-2) during acute human renal allograft rejection. RT-PCR and immunohistochemistry were performed. The COX-2 mRNA was more abundant than COX-1 mRNA in the group with acute rejection (P <.001). The locations of COX-1 and COX-2 protein were consistent with the literature. Expression of COX-2 immunoreactive protein was higher in interstitial cells in the group with acute rejection than in the control group (P =.04). COX-2 protein was more abundant than COX-1 protein in the group with acute rejection, including podocytes (P <.001), proximal tubular cells (P <.001), collecting duct cells (P =.003), and interstitial cells (P <.001). In conclusion, COX-2 which is up-regulated during acute human renal allograft rejection, may play a role in renal inflammation.

Acute Disease↗
PubMed2000

Arterial wall damage caused by snaring of the coronary arteries during off-pump revascularization.

BACKGROUND: Anastomosis of a saphenous or mammary artery conduit to the coronary artery requires precise and reproducible microsurgical technique. Over the past 3 decades, the elective induction of cardiac arrest and circulatory support have provided the conditions suitable for microsurgical anastomosis to all coronary vessels. Beating heart coronary grafting was rejuvenated at our center in 1985 as an alternative to cardiopulmonary bypass and cardioplegic arrest. One of the requirements for off-pump grafting is local vascular control of the target vessel and prevention of bleeding into the field from the open coronary artery. The most common hemostasis technique in use today is the application of circumferential traction sutures and snares around the coronary artery. We performed a human cadaver study to evaluate the potential for local trauma to the native coronary artery caused by this method of hemostasis. METHODS: Our research team applied both 5-0 polypropylene and 2-0 polyester snares to the proximal and distal right coronary artery (RCA) and left anterior descending (LAD) in 25 isolated fresh human cadaver hearts. A total of 100 points of snare application to the native coronary vessels were induced and then investigated histologically, with hematoxylin-eosin, Weigert, and phosphotungstic hematoxylin staining. RESULTS: The results suggested a direct relationship between the severity of the arterial lesion induced by the snares and the degree of local atherosclerotic disease in the native coronary artery. Compression and buckling of the elastic lamellae with medial fractures (similar in nature to angioplasty but directed inward) were seen when snares were applied to a region with marked atherosclerotic disease. CONCLUSIONS: The application of snares to the coronary artery proximal and distal to the anastomotic site must be done with caution. In cases of marked atherosclerotic disease in the underlying coronary artery, a new intimal-medial lesion can occur with indiscriminate application of a tourniquet. This phenomenon may account for some of the reported cases of late peri-anastomotic or distal stenoses seen with off-pump coronary artery bypass grafting and significantly detract from the advantages offered by beating heart surgery. If one or both snares can be avoided entirely, or applied carefully to disease-free segments of the vessel, this problem may be avoided entirely.

Adult↗
PubMed1997

Effects of long-term training on the progression of chronic renal failure in rats.

To evaluate the effects of long-term exercise on the progression of chronic renal failure (CRF), adult Munich-Wistar rats with 5/6 renal mass ablation were submitted to treadmill exercise for 30 min 5 times/wk for 60 d. Whole kidney function and glomerular hemodynamics, proteinuria, and glomerular sclerosis were evaluated in 4 groups: Control, Sham trained (Sham + Ex), rats submitted to 5/6 nephrectomy (CRF) and maintained sedentary, and rats with 5/6 nephrectomy and trained (CRF + Ex). The groups with chronic renal failure (sedentary and trained) presented a reduction in total glomerular filtration rate (GFR) and in renal plasma flow (RPF), accompanied by an increase in single nephron GFR (SNGFR) and glomerular plasma flow (QA). However, the CRF + EX group did not show the glomerular hypertension observed in the CRF group. Despite the normalization of glomerular hypertension, proteinuria and sclerosis index were not different from the CRF sedentary group. Physical training provoked a vasodilatation of efferent arterioles, which induced the normalization of glomerular hypertension. These results suggest that the reduction alone of glomerular hypertension induced by exercise does not prevent the progression of renal disease, indicating the participation of other associated factors in this experimental model.

Animals↗
PubMed1996

Analysis of ICAM-1 and HLA-DR expression on renal allograft aspirates.

ICAM-1 and HLA-DR expressions were studied on parenchymal cells obtained by aspirative biopsies of renal allografts. Patients were evaluated during 3 months after transplantation. Conventional cytology and immunoperoxidase stainings using anti-ICAM-1 and anti-HLA-DR antibodies were employed. The value of the total corrected increment was significantly higher (p < 0.05) during acute rejection episodes than during acute tubular necrosis or stable renal function. The percentage of HLA-DR positive cells were higher in rejection than in stable function periods (p < 0.05). The percentage of ICAM-1 positive cells was higher in rejection than in acute tubular necrosis periods (p < 0.05). The sensitivities to the diagnosis of rejection were 71.8% (TCI), 68.4% (ICAM-1) and 55.0% (HLA-DR). The specificities were 87.3%, 81.3% and 68.4% respectively. Combinations of the tests resulted in increased sensitivity. We concluded that the use of these monoclonal antibodies improves the sensitivity of conventional aspiration cytology to the diagnosis of acute renal rejection.

Biopsy, Needle↗
PubMed1995

FK 506: effects on glomerular hemodynamics and on mesangial cells in culture.

FK 506 is a new immunosuppressive drug that, like cyclosporine A (CsA), presents nephrotoxicity. Glomerular hemodynamic studies showed that acute FK 506 infusion (N = 9, 3 mg/kg body wt, i.v. in bolus) caused a 57% reduction in glomerular filtration rate (GFR) (0.74 +/- 0.03 to 0.32 +/- 0.02 ml/min, P < 0.05) and a 40% reduction in single nephron glomerular filtration rate (SNGFR; 43.0 +/- 5.2 to 26.0 +/- 2.5 nl/min, P < 0.05) due to a 25% reduction in glomerular plasma flow rate (QA) (133.4 +/- 19.8 to 99.8 +/- 12.0 nl/min) and a 22% reduction in glomerular ultrafiltration coefficient (Kf; 0.1009 +/- 0.0203 to 0.0790 +/- 0.0130 nl/sec. mm Hg). After 10 days of FK treatment (N = 8, 0.6 mg/kg body wt, i.p.), we observed a reduction of 23% in GFR (0.97 +/- 0.02 to 0.75 +/- 0.04 ml/min, P < 0.05) and of 23% in SNGFR (37.9 +/- 3.0 to 29.1 +/- 1.9 nl/min, P < 0.05) due to a 42% reduction in Kf (0.1486 +/- 0.0101 to 0.0870 +/- 0.0110 nl/sec.mm Hg, P < 0.05) and a 38% reduction in QA (117.6 +/- 10.2 to 73.5 +/- 6.1 nl/min, P < 0.05). The latter was consequent to the increment of 72% in total arteriolar resistance (RT) (3.1 +/- 0.2 to 5.2 +/- 0.5 +/- 0.5 10(10).dyn.sec.cm-5, P < 0.05). Thus, the pattern of FK 506 effect on glomerular hemodynamics was similar in both acute and chronic treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Epithelial inositol 1,4,5-trisphosphate receptors. Multiplicity of localization, solubility, and isoforms.

In an earlier subcellular fractionation study of epithelial tissue (liver and pancreas), we demonstrated that the inositol 1,4,5-trisphosphate receptor (IP3R) is found in association with biochemically distinct cellular membranes, including the endoplasmic reticulum (ER) and plasma membrane (Sharp, A. H., Snyder, S. H., and Nigam, S. K. (1992) J. Biol. Chem. 267, 7444-7449). To further characterize epithelial IP3Rs, we have now employed cultured Madin-Darby canine kidney (MDCK) cells, a well studied tight polarized epithelial cell type. Indirect immunofluorescence with an antiserum which specifically recognizes IP3R in MDCK cells by immunoblotting and immunoprecipitation gave an ER-like staining pattern as well as a basolateral plasma membrane-like staining pattern, the latter being particularly evident in highly confluent monolayers. In sections of adult rat kidney tubules a similar staining pattern was observed. Interestingly, whereas known basolateral proteins (Na+,K(+)-ATPase and the facilitated glucose transporter) gave a continuous basolateral staining pattern, that seen for IP3R was discontinuous (punctate). A highly similar staining pattern was observed for the caveolar protein, caveolin, suggesting that the punctate basolateral plasma membrane-like staining pattern observed for IP3R reflects its localization to basolateral caveolae. Biotinylation of non-permeabilized and permeabilized MDCK cells, followed by immunoprecipitation of IP3R and detection with streptavidin, indicated that while most IP3R is localized to biotin-inaccessible compartments (i.e. ER), a fraction (10-20%) of IP3R was accessible to externally added biotin primarily from the basolateral side. This result is compatible with the dual ER and basolateral caveolar localization suggested by immunocytochemistry, although it does not exclude the presence of some IP3R in the basolateral plasma membrane as well. Solubility studies revealed IP3R to be considerably more insoluble than the basolateral proteins, Na+,K(+)-ATPase and the liver cell adhesion molecule, as well as the cytoskeletal proteins, ankyrin and fodrin. In the most insoluble fraction, IP3R was found along with caveolin, further supporting the notion that part of the cellular IP3R pool associates with caveolae. Since multiple localizations of IP3R within a cell might reflect the existence of multiple isoforms, polymerase chain reaction amplification of first strand cDNA with primers specific for the three isotypes of IP3R was performed. All three isoforms of IP3R were expressed in the homogeneous population of MDCK cells. The existence of distinct membrane localizations and multiple isoforms of IP3R within the same cell type suggests an explanation for the complex spatiotemporal patterns of Ca2+ release from inositol 1,4,5-trisphosphate-sensitive Ca2+ pools in epithelial and other cells.

Animals↗
PubMed1994

[Comparative study of transthoracic Doppler echocardiogram, computed tomography and aortography in the diagnosis of thoracic aortic dissection].

PURPOSE: Comparative and prospective evaluation of three methods (transthoracic echo-Doppler (TTE), computerized tomography (CT) and aortography (AORT) utilized for aortic dissection diagnosis. METHODS: The 39 patients with confirmed aortic dissection (surgery or autopsy) underwent, within a few hours of each other, all three methods scrutinized. There were 19 cases of type A and 20 of type B dissection. RESULTS: In type A dissection the methods were equivalent (TTE = 73.7%, CT = 84.2%, AORT = 73.7% p = NS) but for type B, TTE was significantly inferior to the other two methods (TTE = 60%, TC 90%, AORT = 80%, p < 0.05 for TTE, for TC and AORT p = NS). In three occasions, even though all three methods were performed, the diagnosis was not obtained. CONCLUSION: The methods which were evaluated make the diagnosis in the majority of cases. In type A all methods are similar, however, in type B, TC and AORT are superior to TTE. Even performing all three methods in each patient, in three instances the diagnosis was not made.

Adult↗
PubMed1993

Modulation of HGF-induced tubulogenesis and branching by multiple phosphorylation mechanisms.

MDCK cells cultured in Type I collagen gels can be induced to develop branching tubular structures with demonstrable lumens in the presence of hepatocyte growth factor (HGF). As we have now shown by immunofluorescent localization of specific marker proteins, these tubules retain apical-basolateral polarity. However, the secondary signaling events which lead to these characteristic morphogenetic changes induced by HGF remain largely unelucidated. In order to examine these signaling events, particularly the role of protein phosphorylation in the formation of branching tubular structures, Madin-Darby canine kidney (MDCK) cells in collagen gels were treated with HGF plus well-characterized agents that affect protein phosphorylation. We quantified the formation of branching processes, an early step in the development of tubular structures in this model. Protein kinase C (PKC) inhibition resulted in more complex branching processes in the presence of HGF, when compared with HGF alone. In contrast, treatment with activators of protein kinase A (PKA), as well as calmodulin antagonists, caused a marked decline in process formation. Consistent with an important role for protein phosphorylation in HGF-induced morphogenesis, protein phosphatase inhibition by okadaic acid or calyculin A was found to markedly inhibit process formation. Tyrosine kinase (TK) inhibition also decreased the percentage of processes. This is consistent with data indicating that one of the HGF receptors is identical to the c-met protooncogene product, which is known to possess TK activity. Our results suggest that the HGF-mediated induction of branching processes in MDCK cells, an early step in the development of branching tubular structures, can be modulated by multiple phosphorylation mechanisms including those mediated by PKC, PKA, and Ca2+/calmodulin-dependent kinase(s). We discuss how these phosphorylation events may play crucial roles in determining the degree of tubule formation and their length, as well as the extent of their arborization during the early development of epithelial tissues.

Alkaloids↗
PubMed1993

Effect of cicletanine on the progression of chronic renal failure in rats.

1. The effects of chronically administered cicletanine (CICL), an antihypertensive and prostacyclin stimulating agent, on glomerular hemodynamics were evaluated after 30 (CRF-30) or 60 (CRF-60) days of chronic renal failure (CRF) induced by 5/6 nephrectomy in Munich-Wistar rats. 2. CICL administration (3 mg kg-1 day-1, N = 5) for 60 days did not modify glomerular hemodynamics of normal rats (control group). The CRF-60 group (N = 6) presented a significant increase in mean arterial pressure (MAP) compared with control (122 +/- 7 vs 98 +/- 2 mmHg, P < 0.05), which was attenuated by CICL (113 +/- 7 vs 122 +/- 7 mmHg). 3. Hyperfiltration and hyperperfusion were observed in both CRF groups after 30 (N = 5) but not after 60 days of CRF, 73.9 +/- 6.3 and 48.2 +/- 3.2 vs 36.8 +/- 2.6 nl/min for SNGFR and 200 +/- 17 and 147 +/- 8 vs 112 +/- 8 nl/min for QA in CRF-30, CRF-60 vs control group, respectively. However, glomerular hypertension was demonstrable for both CRF groups only after 60 days. CICL treatment starting 7 days prior to nephrectomy reduced the transcapillary hydraulic pressure difference (delta P) in both groups, 36 +/- 3 vs 30 +/- 2 mmHg (30 days) and 41 +/- 4 vs 34 +/- 2 (60 days), but did not significantly modify arteriolar resistances or glomerular hemodynamics, suggesting that the reduction in MAP in response to CICL may have been responsible for the decrease in delta P. CICL administration did not prevent the proteinuria or glomerular sclerosis associated with CRF. 4. The results suggest that the administration of CICL for 30 (N = 4) to 60 days (N = 7) was sufficient to prevent systemic hypertension associated with CRF but not to reduce the additional glomerular hemodynamic factors that participate in the progression of CRF.

Animals↗
PubMed1992

Effect of eicosapentaenoic acid on the progression of chronic renal failure in rats.

Eicosapentaenoic acid (EPA) can induce a shift in prostaglandin and leukotriene synthesis. The effects of EPA supplementation of the diet on the progression of chronic renal failure (CRF) were evaluated in a model of 5/6 renal mass ablation in rats. After 30 or 60 days of CRF, elevation in single-nephron glomerular filtration rate due to an increase in glomerular plasma flow and hydraulic pressure was observed. These hemodynamic alterations were followed by a rise in proteinuria and glomerular sclerosis. EPA treatment for 30 or 60 days did not substantially modify the hemodynamic or morphological profiles induced by renal mass ablation. In the present non-immune model of CRF, preglomerular vasodilation with glomerular hyperperfusion and hypertension were responsible, at least in part, for the presence of proteinuria and glomerular sclerosis. No additional vasodilation was observed in the present model of CRF, and, thus, hemodynamic effects induced by EPA did not modify renal damage, in contrast to the EPA effects observed in immune-mediated models of CRF.

Animals↗
PubMed1988

Glomerular hematuria in diabetics.

Three hundred and twenty outpatients with diabetes mellitus (DM) were studied to evaluate the prevalence, origin (glomerular or nonglomerular), significance and possible association of glomerular hematuria (GH) with other clinical and laboratory features. In patients with 24 h proteinuria equal or superior to 500 mg, hematuria was seen in 16 out of 22 (72.7%); for those with 24 h proteinuria between 150 and 500 mg 5 out of 23 (21.7%) had hematuria, and in the general population of diabetics studied hematuria was present in 47 patients (14.7%). It was glomerular in 43 (13.4%) patients and nonglomerular in 4 (1.3%). Red blood cell casts were observed in 15 (34.9%) out of the 43 patients with GH. Ten out of 31 patients (32.3%) with GH, for whom 24 h proteinuria was available, had negative proteinuria in a 24 h urine when analyzed by routine methods. In 18 patients with GH, clinical and laboratory findings that could suggest a second form of glomerulopathy--nondiabetic--were negative. Renal biopsy in 9 of them showed only diabetic glomerulosclerosis. We have observed a significant association between GH and the male sex (p less than 0.001), high serum creatinine levels (p = 0.0002) and 24 h proteinuria greater than 150 mg (p less than 0.001). GH was more frequent among males with DM lasting more than 10 years (p less than 0.001) and among those with retinopathy (p less than 0.001). There was no association between GH and age, type of DM, insulin requirement or hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Release of lactate dehydrogenase activity by rabbit renal cortex slices during storage in solutions used for kidney transplantation.

Lactate dehydrogenase (LDH) activity was evaluated after incubation of rabbit renal cortical slices in several preservation solutions. Experimental solutions commonly used for kidney transplantation decreased LDH activity up to 72 h of storage at 4 degrees C compared to a control plasma-like solution. Low temperature (4 degrees C) storage led to a smaller release of LDH than slices preserved at 25 degrees C in control solutions. The addition of organic substrates to the control solution diminished enzyme release only of those slices incubated at 25 degrees C. After 72 h of incubation, the rate of LDH release was constant for all solutions except Collins glucose 330 mOsm solution for which the rate increased still further up to 96 h. The lower rate of LDH release exhibited by experimental solutions for up to 72 h indicates the maintenance of cellular integrity and hence of tissue viability. On the other hand, the continued increase of the rate of LDH release shown by Collins glucose 300 mOsm solution up to 96 h may suggest an even higher survival of viable cells and the stabilization of the rate of LDH release observed in the latter period of storage may indicate the onset of necrosis.

Animals↗
PubMedDate not supplied

The use of cyclosporine modifies the clinical and histopathological presentation of tuberculosis after renal transplantation.

Tuberculosis is one of the most frequent opportunistic infections after renal transplantation and occurred in 30 of 1264 patients transplanted between 1976 and 1996 at Hospital São Paulo - UNIFESP and Hospital Dom Silvério, Brazil. The incidence of 2.4% is five times higher than the Brazilian general population. The disease occurred between 50 days to 18 years after the transplant, and had an earlier and worse development in patients receiving azathioprine, prednisone and cyclosporine, with 35% presenting as a disseminated disease, while all patients receiving azathioprine and prednisone had exclusively pulmonary disease. Ninety percent of those patients had fever as the major initial clinical manifestation. Diagnosis was made by biopsy of the lesion (50%), positivity to M. tuberculosis in the sputum (30%) and spinal cerebral fluid analysis (7%). Duration of treatment ranged from 6 to 13 months and hepatotoxicity occurred in 3 patients. The patients who died had a significant greater number of rejection episodes and received higher doses of corticosteroid. In conclusion, the administration of cyclosporine changed the clinical and histopathological pattern of tuberculosis occurring after renal transplantation.

Adolescent↗
PubMedDate not supplied

[Polyalveolosis: pathogenesis of congenital lobar emphysema?].

BACKGROUND: Congenital lobar emphysema is an unusual condition and its pathogenesis remains unknown. The variety of findings in pathology studies of the resected specimens led to increasing academic interest. About 50 per cent of the cases have no definitive diagnosis in pathology. The most recent theory proposes an increased number of alveoli within each acinus (polyalveolar lobe). PURPOSE: The aim of this paper is to report the morphometric measures of surgical specimens of 12 patients with congenital lobar emphysema, using the Emery and Mithal technique (radial alveolar count). METHODS: We made a case-control study, classifying the cases by age. Mann-Whitney's U test and linear regression techniques were used in data analysis: Mann-Whitney's U in comparing the cases and respective controls and linear regression to evaluate the influence of age in the measures found. RESULTS: The results revealed a significantly higher radial alveolar count than expected for the age group under 3 years; no difference was observed in the age group between 3 and 7 years and in children older than 7, the radial alveolar count was lower than expected. The normal development of the lung consists in an increasing number of alveoli increase from birth until adulthood, but this number remains constant, independent of age in congenital lobar emphysema. CONCLUSIONS: Such findings allow us to conclude that polyalveolar lobe can and must be diagnosed by a simple and practical method, such as the radial alveolar count, which decreases the incidence of the unknown etiology. The findings of an increased number of alveoli on patients younger than 3 is related to congenital lobar emphysema, since the number of alveoli does not increase in congenital lobar emphysema, just the opposite to what one would expect in the normal development of the lung.

Adolescent↗
PubMedDate not supplied

Ligation of the left renal vein in epm1-Wistar rats: functional and morphologic alterations in the kidneys, testes and suprarenal glands.

OBJECTIVE: The ligation of the left renal vein (LLVR) in man is a controversial procedure in view of the risks of lesion to the renal parenchyma. With the objective of studying the morphologic and functional alterations caused by these lesions, we conducted experimental research with rats. MATERIAL AND METHODS: 64 male adult EPM1-WISTAR rats were used, divided into 8 groups-4 for LLRV and four for control. Each LLRV group and corresponding control group were sacrificed progressively on the 7th, 15th, 30th and 60th day after the initial surgery. RESULTS: We found morphofunctional alterations only in animals that underwent LLRV in the four periods of sacrifice. The proteinuria creatinine in serum, testosterone in serum and serum corticosterone in serum showed practically no alteration in relation to the normal values for rats. Statistically significant severe histological lesions were found in the kidneys and testes of the LLRV groups. Lesions in the suprarenal glands were also present in these groups, but no sufficient to demonstrate statistical significance. CONCLUSION: Based on these results we can conclude that the ligation of the left renal vein is a procedure of high risk in these animals.

Adrenal Glands↗