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S Lara

Publications and source records attributed to S Lara.

12 recordsLinked to original sources
PubMed1997

Selective deposits of versican in the extracellular matrix of restenotic lesions from human peripheral arteries.

Although a large percentage of the volume of human restenotic arterial lesions is occupied by extracellular matrix (ECM), the composition and organization of this ECM are not well characterized. In this study, restenotic segments taken from 30 human peripheral arteries by directional atherectomy at times ranging from 13 days to 36 months after angioplasty were analyzed for specific patterns of ECM composition and organization by light and electron microscopic histochemistry and immunohistochemistry. Histochemical analysis revealed the presence of distinct zones, enriched either in proteoglycans or fibrillar collagen. Most sections contained these regions juxtaposed to each other. The frequency of these two distinct ECMs did not change as a function of time after angioplasty. The collagen-rich zone usually contained elongated smooth muscle cells spaced close together except in regions resembling fibrous plaques. The proteoglycan-rich ECM contained both elongated and stellate-shaped smooth muscle cells randomly arranged and separated by wide distances. This region resembled the loose-connective-tissue-containing myxoid region typical of restenotic lesions. Immunohistochemical analysis of these regions revealed that the proteoglycan-containing zone stained intensely for versican, a large interstitial chondroitin sulfate proteoglycan, whereas the collagen-containing areas were mostly negative for versican but positive for type I collagen. The versican-positive regions also immunostained for biglycan, a small leucine-rich dermatan sulfate proteoglycan, and sparsely for elastin. However, both of these ECM molecules were present in the versican-negative type I collagen-positive regions of the lesions. These results suggest that the development of restenotic lesions involves localized deposits of specific ECM molecules that may play a role in the asymmetric renarrowing of this tissue after angioplasty.

Angioplasty, Balloon↗
PubMed1996

Significant increase in eradication rates of Helicobacter pylori infection with two consecutive dual therapies (omeprazole and amoxycillin or omeprazole and clarithromycin). A randomized study in 450 Spanish patients.

Helicobacter pylori infection is associated with peptic ulcer disease and chronic gastritis, and eradication of the microorganism markedly reduces the recurrence of peptic ulcer. However, a major problem is the choice of a treatment that is effective, has high eradication rate, and is well tolerated by patients. We evaluated the eradication of H. pylori infection in patients with chronic gastritis (CG), duodenal ulcer (DU), and gastric ulcer (GU) after two dual therapies (omeprazole with either amoxycillin or clarithromycin). Of 450 patients initially included in the study, 207 had CG, 187 DU and 56 GU, and all presented with H. pylori infection. Diagnosis was made from endoscope examination, biopsy samples, rapid urease test and 13C-urea breath test (UBT). H. pylori infection was considered to be present when two of the tests had positive results. All patients were randomized to one of two regimens: (A) omeprazole (20 mg b.i.d.) plus amoxycillin (750 mg t.i.d.) or (B) omeprazole (40 mg b.i.d.) plus clarithromycin (500 mg t.i.d.). The duration of each of the regimens was 2 weeks. Fifty-eight patients who showed H. pylori infection after the first treatment (27 with CG, 24 with DU, and 7 with GU) were allocated to a second therapy. H. pylori eradication was assessed by UBT, 6 weeks after the end of the therapies; positive values were those higher than 5 delta units. A second consecutive dual therapy of omeprazole plus an antibiotic (amoxycillin or clarithromycin) not used in the first therapy improved on the eradication rates obtained with the first regimen. The overall eradication rates were also higher, but no significant differences were found between amoxycillin and clarithromycin. The best results were obtained in those patients with GU.

Adult↗
PubMed1993

A study of the lactic dehydrogenase isoenzyme patterns in the adenoma--carcinoma sequence of the colon.

In order to determine whether the LDH isoenzyme pattern, measuring the percentages of LDH4-5 (M monomer), might be a marker in the adenoma-carcinoma sequence, 103 adenomas, 8 adenomas with proven malignant degeneration and 27 adenocarcinomas of the large intestine, as well as 12 biopsy samples of colonic mucosa from normal controls, were studied histologically and histochemically. The proportion of M polypeptide was significantly increased in adenomas of larger size (diameter > 2 cm), in adenomas with a larger villous component, and in those with severe dysplasia. The largest proportion of M polypeptide was found in villous adenomas and colloid adenocarcinomas, and might reflect a common origin. These results suggest that the histochemical study of the LDH isoenzymogram might be a useful marker for detecting early malignant degeneration in adenomas of the colon.

Adenocarcinoma↗
PubMed1989

Cationic dyes reveal proteoglycans structurally integrated within the characteristic lesions of Alzheimer's disease.

The cationic dyes ruthenium red (RR) and cuprolinic blue (CB) were used to preserve proteoglycans (PGs) for visualization at the ultrastructural level in brain tissue from seven cases of Alzheimer's disease (obtained at autopsy within 3-4 h after death). PGs were visualized as RR-positive granules specifically localized to the amyloid fibrils in neuritic plaques. In neurofibrillary tangles, RR granules were localized to the paired helical filaments and straight filaments usually at a consistent periodicity of 40-70 nm. CB, known to preserve PGs as short punctate filaments, also demonstrated PGs specifically localized to the amyloid fibrils in neuritic plaques and in association with paired helical filaments and straight filaments in neurofibrillary tangles. Persistent staining with CB at magnesium chloride concentrations of 0.3 and 0.7 M in the neuritic plaques suggested the presence of highly sulfated PGs, whereas abolishment of CB staining at 0.7 M magnesium chloride in the neurofibrillary tangles implied that different PGs and/or glycosaminoglycans were present in the neurofibrillary tangles. The specific ultrastructural localization of PGs to the characteristic lesions in Alzheimer's disease suggests that PGs are part of a complex structural network with amyloid fibrils in neuritic plaques and the filamentous structures present in neurofibrillary tangles.

Alzheimer Disease↗
PubMed1988

Arterial chondroitin sulfate proteoglycan: localization with a monoclonal antibody.

We generated a monoclonal antibody (Mab) against a large chondroitin sulfate proteoglycan (CSPG) isolated from bovine aorta. This Mab (941) immunoprecipitates a CSPG synthesized by cultured monkey arterial smooth muscle cells. The immunoprecipitated CSPG is totally susceptible to chondroitinase ABC digestion and possesses a core glycoprotein of Mr approximately 400-500 KD. By use of immunofluorescence light microscopy and immunogold electron microscopy, the PG recognized by this Mab was shown to be deposited in the extracellular matrix of monkey arterial smooth muscle cell cultures in clusters which were not part of other fibrous matrix components and not associated with the cell's plasma membrane. With similar immunolocalization techniques, the CSPG antigen was found enriched in the intima and present in the medial portions of normal blood vessels, as well as in the interstitial matrix of thickened intimal lesions of atherosclerotic vessels. Immunoelectron microscopy revealed that this CSPG was confined principally to the space within the extracellular matrix not occupied by other matrix components, such as collagen and elastic fibers. These results indicate that this particular proteoglycan has a specific but restricted distribution in the extracellular matrix of arterial tissue.

Animals↗
PubMed1986

The melanoma proteoglycan: restricted expression on microspikes, a specific microdomain of the cell surface.

A cell surface chondroitin sulfate proteoglycan associated with human melanomas and defined by mAb's F24.47 and 48.7 has been characterized biochemically and localized by indirect immunogold electron microscopy. These antibodies recognize distinct epitopes on the intact proteoglycan. In addition, mAb 48.7 also recognizes an epitope on a 250,000-D glycoprotein and is therefore similar to antibody 9.2.27 (described by Bumol, T.F., and R.A. Reisfeld, 1982, Proc. Natl. Acad. Sci. USA., 79:1245-1249). Furthermore, it was shown that the glycosaminoglycan chains released by alkaline borohydride treatment of the proteoglycan recognized by mAb 48.7 had a size of approximately 60,000 D. Since the intact proteoglycan was estimated to be 420,000 D, there are probably three chondroitin sulfate chains attached to the 250,000-D core glycoprotein. Furthermore, an oligosaccharide fraction containing 42% of the 3H activity (glucosamine as precursor) was isolated. Immunolocalization studies using whole-mount electron microscopy revealed that the chondroitin sulfate proteoglycan was present almost exclusively on microspikes, a microdomain of the melanoma cell surface. These processes were present as 1-2-micron structures on the upper cell surface and as longer (up to 20 micron) structures at the cell periphery. Peripheral microspikes were involved in the initial interactions between adjacent cells and formed complex footpads that made contact with the substratum. Immunogold-labeled cells were also thin sectioned and the specific localization of the chondroitin sulfate proteoglycan antigen was quantitated. The data confirmed the results of whole-mount microscopy and demonstrated a statistically significant association of the antigen with the microspike processes as compared with other areas of the cell surface. By using two different mAb's (48.7 and F24.47) that recognize epitopes on either the core glycoprotein or the intact proteoglycan, respectively, we have demonstrated that both molecules have the same restricted distribution at the cell surface. The specific localization of the antigen to microspikes at the cell surface suggests it may play a role in cell-cell contact and cell-substratum adhesion, which could be important in the metastatic process.

Aggrecans↗
PubMed1981

[Extramedullary plasmacytoma. Presentation of 3 cases].

The authors report three cases of extramedullary plasmacytoma, localized in the oral cavity, deltoid muscle and upper respiratory passages, respectively. The first case was followed for seven years until his death, the second case has been followed during nine years and is still alive and the third one is a recently diagnosed case.

Adenocarcinoma↗
PubMedDate not supplied

[Anemia in pregnant women of Sobradinho, a satellite city of Brazilia, Brazil (author's transl)].

Four hundred and seven pregnant women, living in Sobradinho, a satellite city of Brasilia, Brazil, divided in three groups according to their gestation age: I trimester (50 cases); II trimester (140 cases); III trimester (201 cases), were studied for the hemoglobin concentration of their blood and intestinal parasitism. In nineteen of the anemic women iron, folic acid and vitamin B12 serum determinations were done. The mean hemoglobin concentration and the percentage of anemia (less than 12 g/100 ml) in the different stages of gestation, were: 13.06 g/100 ml and 22% for the first trimester: 12.49 g/100 ml and 29% for the second trimester and 12.11 g/100 ml and 34% for the third trimester. In the 19 cases of the anemic group studied we found 73.7% of iron deficiency (below 60 microg/100 ml); 26.3% of folic acid deficiency (below 4 ng/ml) and 10.5% of vitamin B12 deficiency (below 140 pg/ ml). A combined deficiency occured in two cases: iron plus folic acid (case 11, table 3) and folic acid plus vitamin B12 (case 3, table 3). The stool examination showed parasitic infection, in 51% of the women.

Anemia↗
PubMedDate not supplied

[Radiofrequency ablation in the treatment of supraventricular tachyarrhythmia. Experience with 500 consecutive patients].

Several reports have demonstrated that radiofrequency catheter ablation provides effective control of a variety of supraventricular tachyarrhythmias. This report details the results of radiofrequency catheter ablation in 500 consecutive patients with a wide variety of supraventricular tachycardia treated at the Instituto Nacional de Cardiología "Ignacio Chaávez". Tachyarrhythmias were associated with the presence of an accessory pathway in 355 patients (71%). The accessory pathways were capable of both anterograde and retrograde conduction in 220 of cases (60%), only retrograde conduction in 146 (40%), dual accessory pathways were present in 11 patients (2.2%) giving a total of 366 accessory pathways. The mechanism of the arrhythmia was AV nodal reentrant tachycardia in 115 patients (23%). Ablation of the reentrant circuit of atrial flutter within the right atrium was attempted in 15 (15%) patients and a primary atrial tachycardia in 3 patients (0.7%). AV node ablation and permanent pacemaker implantation were performed in 11 patients (2%). Radiofrequency catheter ablation was successful in 312 of 355 (87.9%) patients with accessory pathways 312 of 366 (85.2%) pathways with a complication rate of 6/355 (2%) and a recurrence rate of (12.4%). AV nodal reentry was successfully abolished in 110 of 115 patients by selective ablation of the slow pathway in 92/96 (95.8%) patients and the fast pathway in 18/19 (94.7%) patients. The complication rate of this group was 7/115 (6.0%) with a recurrence rate of 16 patients (12%). The reentrant circuit of atrial flutter was ablated successfully in 13 of 15 patients with recurrent atrial flutter in (27%) patients. 2/3 (66%) primary atrial tachycardia were successfully ablated. Complete AV block was achieved in 11 of 11 patients with atrial fibrillation or flutter treated by AV nodal ablation without complications or recurrence. The results of this series of patients demonstrates the safety and efficacy of radiofrequency ablation for the treatment of a wide variety of supraventricular arrhythmias with high rate of success and low risk of complications.

Adolescent↗
PubMedDate not supplied

[Radiofrequency ablation in multiple accessory pathways].

Radiofrequency ablation were performed in 465 consecutive patients with Wolff-Parkinson-White syndrome. We demonstrated evidence of multiple accessory pathways in 18 patients (3.9%); 17 had two, and one had three accessory pathways. In three of these there was additional right atrio-fascicular connection. There were 27 manifest and 10 concealed accessory pathways. Six patients had Ebstein's anomaly associated with accessory pathways. The location of the accessory pathways was in the right posterior portion of the ventricular septum in 16, the left posterior portion of the ventricular septum in 5, the right free wall in 5, the left wall in 7, the right anteroseptal in 3, the midseptum in 1, and one right anterolateral. Of the 37 pathways, 32 (86%) accessory pathways were ablated successfully without complications. Duration of the procedure was 100 +/- 58 minutes, and fluoroscopic time 40 +/- 17 minutes. The mean applications were 26 +/- 17 and the power level of the radiofrequency current 41 +/- 6 W. A follow-up of 80 +/- 40 days after ablation demonstrated incidence of recurrent conduction in 3 accessory pathways (8%). In conclusion, patients with multiple accessory pathways can be treated by radiofrequency ablation in a single session with a high success rate although slightly less than that in patients with a single accessory pathway.

Catheter Ablation↗