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Biomedical subjects

S Perez

Publications and source records attributed to S Perez.

At least 55 records · Page 3Linked to original sources
PubMed1995

Anti-inflammatory activity of the bark of Hippocratea excelsa.

The ethanol extract of the plant Hippocratea excelsa was examined for its anti-inflammatory effects using several animal models. It produced significant inhibition of carrageenan-induced paw edema and reduced the weight of cotton pellet-induced granuloma at doses of 25-100 mg/kg. The extract was found to exert a protective effect on heat-induced erythrocyte lysis at concentrations of 25, 50 and 100 micrograms/ml. In chronic models of formaldehyde and adjuvant arthritis, its anti-arthritic activity was found to be less than that of phenylbutazone (PNB). It may be inferred that the ethanol extract is effective against both exudative-proliferative and chronic phases of inflammation.

Animals↗
PubMed1995

Intrapleural chemotherapy for patients with incompletely resected malignant mesothelioma: the UCLA experience.

From 1986 to 1993, 15 patients with malignant pleural mesothelioma were treated by pleurectomy/decortication and intrapleural cisplatin (100 mg/m2) and cytosine arabinoside (1,200 mg). All patients were without known extrathoracic disease and had a mean age of 63 +/- 7.9 years (range 51-78); 13 were male. Histologic subtype of disease were epithelial (47%), sarcomatoid (27%), and mixed-biphasic (27%). The major morbidity and mortality rates were 13% and 0%, respectively. The mean length of hospital stay was 6.5 +/- 2.1 days. Postoperatively, adjuvant chemotherapy and radiation therapy were given to 46% and 73% of the patients respectively. Median survival from date of treatment was 11.5 months. Those patients with an epithelial histologic subtype experienced significantly improved survival compared to those of sarcomatoid subtype (P = 0.024). Whether adjuvant chemotherapy or radiation therapy were given had no significant effect on survival. These data suggest that although this treatment regimen can be administered with very limited morbidity and no mortality, the role of this approach in the treatment of malignant pleural mesothelioma appears limited and cannot currently be recommended.

Aged↗
PubMed1995

Prefeeding potentiates anorectic actions of neuromedin B and gastrin releasing peptide.

We report that the anorectic potency of neuromedin B (NMB) and gastrin-releasing peptide (GRP) is potentiated using a prefeed paradigm. During the light phase, adult male Sprague-Dawley rats (groups of n = 6) were given 30-min (pre-feed) access to a liquid diet. Thirty min later rats were injected i.p. with GRP or NMB (0, 8, 16, 32 or 64 micrograms kg-1) and given further access to the liquid diet. In prefed (PF) rats, high doses of NMB (32 and 64 micrograms kg-1) delayed the onset of eating in the test by > 10 min, significantly suppressing 30-min intake. The same doses of NMB in non prefed (NPF) rats were ineffective. Weak effects of GRP in NPF rats to reduce meal size were also enhanced under PF conditions. Exogenous GRP and NMB, in particular, appear to interact with processes stimulated by the postingestive actions of food, supporting a role for peripheral, endogenous GRP and NMB in the development of satiation and the maintenance of postprandial satiety, respectively.

Animals↗
PubMed1995

[Kinetics of lipid peroxidation induced by UV beta rays in human keratinocyte and fibroblast cultures].

Lipid peroxidation has been implicated in skin damage by ultraviolet radiation. The aim of the study was to determine the kinetic of lipid peroxidation induced by ultraviolet beta (UVB) in adult keratinocytes and fibroblasts in culture. The keratinocytes were obtained from a single primary culture and the fibroblasts were in the same subculture (4 to 10 transfers). For UVB irradiation, the cells were maintained in a small volume of Hanks balanced salt solution and were irradiated (0.75, 1.5, 3 and 4.5 Jcm-2). Then cells were cultured for 3 to 48 hours. Lipid peroxidation was estimated by free MDA determination in both extracellular medium and cells using a size exclusion chromatography coupled to an HPLC procedure. In addition, LDH release in culture media was evaluated as in indice of cytotoxicity. An increase of total free MDA was observed 3 hours after cell irradiation which was dose-dependent from 0.75 to 3 Jcm-2 for keratinocytes and fibroblasts. MDA was detected both in cells and in culture media. As soon as 3 hours after irradiation 90% in total MDA was present in the culture media. Kinetic of lipid peroxidation: for 0.75 Jcm-2, an elevation of MDA was observed 12 hours after irradiation in both cultures. A further increase in MDA was noted 24 hours after fibroblasts irradiation but not in irradiated keratinocytes. LDH release in culture media increased with post irradiation time until 48 hours. The cytotoxic effect of UVB irradiation on keratinocytes and fibroblasts cultures was shown by an enhancement of lipid peroxidation which was detectable during 48 hours after irradiation. An increase of LDH release was observed simultaneously.

Adult↗
PubMed1994

The monosaccharide binding site of lentil lectin: an X-ray and molecular modelling study.

The X-ray crystal structure of lentil lectin in complex with alpha-D-glucopyranose has been determined by molecular replacement and refined to an R-value of 0.20 at 3.0 A resolution. The glucose interacts with the protein in a manner similar to that found in the mannose complexes of concanavalin A, pea lectin and isolectin I from Lathyrus ochrus. The complex is stabilized by a network of hydrogen bonds involving the carbohydrate oxygens O6, O4, O3 and O5. In addition, the alpha-D-glucopyranose residue makes van der Waals contacts with the protein, involving the phenyl ring of Phe123 beta. The overall structure of lentil lectin, at this resolution, does not differ significantly from the highly refined structures of the uncomplexed lectin. Molecular docking studies were performed with mannose and its 2-O and 3-O-m-nitro-benzyl derivatives to explain their high affinity binding. The interactions of the modelled mannose with lentil lectin agree well with those observed experimentally for the protein-carbohydrate complex. The highly flexible Me-2-O-(m-nitro-benzyl)-alpha-D-mannopyranoside and Me-3-O-(m-nitro-benzyl)-alpha-D-mannopyranoside become conformationally restricted upon binding to lentil lectin. For best orientations of the two substrates in the combining site, the loss of entropy is accompanied by the formation of a strong hydrogen bond between the nitro group and one amino acid, Gly97 beta and Asn125 beta, respectively, along with the establishment of van der Waals interactions between the benzyl group and the aromatic amino acids Tyr100 beta and Trp128 beta.

Binding Sites↗
PubMed1993

Frequency and distribution of occult micrometastases in lymph nodes of patients with non-small-cell lung carcinoma.

BACKGROUND: Accurate assessment of the presence and absence of tumor in the regional lymph nodes is critical in assessment of prognosis for patients with lung cancer. Development of sensitive immunohistochemical techniques and specific monoclonal antibodies has increased our capacity, in melanoma and breast cancer, to detect small groups of tumor cells or even single tumor cells in lymph nodes that appear to be tumor free in conventionally stained sections. PURPOSE: This retrospective study was designed to assess whether use of a polyclonal antikeratin reagent in immunohistochemical analysis offers any advantage over conventional histopathology in detection of regional lymph node metastases in non-small-cell lung cancer. METHODS: Paraffin-embedded tissue sections from regional lymph nodes of 65 patients with non-small-cell lung cancer were studied. We examined tissue from 588 nodes of 60 patients with a diagnosis of disease confined to the lung and from 72 nodes of five patients with a diagnosis of metastasis to some nodes. A polyclonal antikeratin antibody was applied to the lymph node tissue sections, using the avidin-biotin complex immunoperoxidase technique. RESULTS: Single tumor cells and small clusters of tumor cells (occult micrometastases) not visible on routine evaluation were readily detected in 38 (63%) of the 60 patients whose nodes appeared to be negative on examination of hematoxylin-eosin-stained slides. In the five patients with a diagnosis of node-positive non-small-cell lung cancer, five (10%) of 51 nodes that were tumor free on conventional examination contained metastases. Metastatic tumor cells were most often located in the subcapsular or medullary sinuses. The lymph nodes that contained occult tumor cells were those located nearest to the tumor, mainly in peribronchial and hilar locations. The median survival of patients with occult metastases (1977 days) was shorter than that of patients whose nodes contained no tumor (2456 days) but was longer than that of patients whose nodes contained metastases detectable on hematoxylin-eosin-stained slides (927 days). CONCLUSIONS: Our results suggest that, in patients with non-small-cell lung cancer, metastatic involvement of regional lymph nodes is more frequent than was previously determined by the conventional histologic method and substantially more frequent than in other tumor types, such as melanoma and breast cancer. IMPLICATIONS: The high frequency of occult nodal metastases in non-small-cell lung cancer makes it clear that, without immunohistochemistry, disease is understaged in many patients. Therefore, it seems essential that immunohistochemical evaluation of the lymph nodes be undertaken in clinical trials.

Adult↗
PubMed1993

Bioactive compounds from the buds of Platanus orientalis and isolation of a new kaempferol glycoside.

A new compound kaempferol 3-O-alpha-L-(2"-E-p-coumaroyl)-rhamnopyranoside, as well as the known flavonoids, kaempferol 3-O-beta-D-(6"-E-p-coumaroyl)-glucopyranoside, kaempferol 3-O-alpha-L-(2",3"-di-E-p-coumaroyl)-rhamnopyranoside, and caffeic acid were obtained from the methanolic extract of Platanus orientalis L. buds. All the compounds were isolated by column chromatography and identified using 1H-NMR, 2D-1H-NMR (COSY), 1H-13C-NMR, and CIDMS techniques. Cytotoxic and antimicrobial studies were carried out in vitro against human cell lines and against Gram-positive and Gram-negative organisms.

Anti-Infective Agents↗
PubMed1992

The use of nylon wool for the isolation of T lymphocyte subpopulations.

A simple method for the affinity isolation of lymphocyte subpopulations using nylon wool as a solid phase matrix is described. This matrix was coated with an acid-treated IgG fraction of polyclonal antibodies against mouse immunoglobulins. Using this approach, a simple isolation procedure for lymphocyte subpopulations, yielding purities higher than 95% was developed. The method can be used on a large scale for positive and negative cell selection, with very little non-specific binding. The isolated populations are fully functional.

Animals↗
PubMed1992

Relation of plasma lipid and apoprotein levels to progressive intimal hyperplasia after arterial endarterectomy.

BACKGROUND: To examine the relation of plasma lipoproteins to the proliferative response after arterial injury in humans, we examined the plasma lipid, lipoprotein, and apoprotein levels of 20 patients with early recurrent stenosis caused by intimal hyperplasia after carotid endarterectomy. These were compared with 20 controls who had no evidence of recurrent stenosis by duplex ultrasound scanning. METHODS AND RESULTS: By univariate analysis, the reoperated patients had higher levels of plasma cholesterol (251 versus 225 mg/dl, p less than 0.05), total triglycerides (173 versus 105 mg/dl, p less than 0.03), and low density lipoprotein (LDL) apoprotein B (99.8 versus 77.2 mg/dl, p less than 0.003). The ratio of cholesterol to apoprotein B in LDL was lower in patients with restenosis (p less than 0.04), suggesting LDL of smaller diameter. High density lipoprotein (HDL) cholesterol level was reduced (45 versus 55 mg/dl, p less than 0.01) in patients with restenosis. With statistical adjustment for the correlations between these variables by multivariate analysis, both LDL apoprotein B and HDL cholesterol were independent predictors of the risk of restenosis. Ten patients with restenosis but only two controls had one or two apolipoprotein E4 alleles. CONCLUSIONS: Elevated lipid levels usually associated with an increased risk of atherosclerosis may predispose patients to an increased incidence of intimal hyperplasia after endarterectomy.

Aged↗
PubMed1992

Magnetic resonance angiography of the carotid artery combining two- and three-dimensional acquisitions.

To assess the agreement between magnetic resonance angiography and conventional angiography in the evaluation of carotid stenosis, 61 carotid arteries of 40 patients were studied by combined two- and three-dimensional magnetic resonance angiography and conventional angiography. Stenosis of the internal carotid artery was categorized as mild, moderate, severe, critical, or complete occlusion. In 42 arteries, the degree of stenosis according to magnetic resonance angiography correlated exactly to that found by conventional angiography. In the remaining 19 carotid arteries, the magnetic resonance angiographic measurement of stenosis differed from the conventional angiographic measurement by only one size category. The Spearman rank correlation coefficient was 0.95 (p < 0.001). This study showed that by combining information from two- and three-dimensional magnetic resonance angiographic studies and making use of the advantages of each method, magnetic resonance angiography was comparable to conventional angiography in determining carotid stenosis. Magnetic resonance angiography tended to demonstrate a higher level of stenosis when there was a discrepancy. These data demonstrate that magnetic resonance angiography is a steadily improving technology. Although additional studies need to be done, it seems clear that magnetic resonance angiography will be an imaging modality comparable in accuracy to conventional angiography.

Aged↗
PubMed1991

Simultaneous resection of renal carcinoma and abdominal aortic aneurysm.

A 62-year-old man with a 6.5 cm abdominal aortic aneurysm and coexistent left renal cell carcinoma was treated by simultaneous radical left nephrectomy and abdominal aortic aneurysm repair. Care was taken to avoid potential infection of the bypass graft by inadvertent contamination with urine. Pathologic examination of the left kidney revealed a renal cell carcinoma, clear cell type, with no evidence of invasion into the renal vein or lymph node metastases. The patient had an uncomplicated recovery and is well and free of disease four years after operation. In cases of equivalently life threatening surgical diseases, simultaneous resection is warranted.

Aorta, Abdominal↗
PubMed1991

Lower-extremity vascular grafts placed for peripheral vascular disease: prospective evaluation with duplex Doppler sonography.

Eighty-five men with 92 vascular grafts placed for peripheral vascular disease of the lower extremity underwent a total of 264 examinations with duplex Doppler over a 2.5-year period. In 64 patients who underwent more than one examination, the total follow-up encompassed 740 months. In 220 native femoral arteries (96.0%) the peak systolic velocity (PSV) was higher than that in the graft. Arteriovenous shunting was associated with a normal PSV and a markedly elevated diastolic component at spectral analysis. Focal fluid collections were common initially near the graft and usually disappeared uneventfully. An average PSV of 32 cm/sec or less was always associated with impending occlusion. The sensitivity of an average PSV of 40 cm/sec or less to indicate impending graft occlusion by the next visit was only 33%; the specificity, 94%. At initial examination, stenoses were associated with high PSV focally in the graft or low PSV with absent diastolic flow.

Aged↗
PubMed1991

A prospective randomized trial of autologous platelet-derived wound healing factors for treatment of chronic nonhealing wounds: a preliminary report.

Previous studies have suggested that topically applied platelet-derived wound healing factors (PDWHF) accelerate wound healing by stimulating angiogenesis, fibroblast proliferation, and collagen synthesis. To assess the ability of platelet factors to facilitate healing of chronic cutaneous ulcers we performed a randomized, prospective, double-blind, placebo-controlled study of topical PDWHF in 18 patients with 26 lower extremity wounds refractory to conventional therapy. Wounds were present for at least 8 weeks (mean, 5.5 +/- 4.3 months). They were extensively debrided initially and were measured and photographed at weekly intervals for 12 weeks. Eight patients with nine wounds were treated with placebo solution (controls), and 10 patients with 17 wounds were treated with PDWHF (treatment group). Seventy-eight percent of patients had diabetes mellitus, 72% had occlusive peripheral vascular disease, and 28% had venous disease; distribution of these disorders was equivalent in both groups. Ankle-brachial indexes, which were often spuriously elevated, averaged 0.93 +/- 0.54 in controls and 1.04 +/- 0.56 in patients treated with PDWHF (p greater than 0.5). Mean transcutaneous oxygen tension was 37.8 +/- 11.9 mmHg in controls and 37.1 +/- 9.1 mmHg in patients treated with PDWHF. Initial wound area was larger in controls than in the patients treated with PDWHF (28.9 +/- 45.2 cm2 vs 13.0 +/- 4.4 cm2), but this difference was not statistically significant (p = 0.19). Three (33%) wounds (in two patients) healed in controls, and four (24%) wounds (in three patients) healed in the PDWHF group (p greater than 0.5). The rate of healing in controls was 1.9 +/- 2.7 cm2/week.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1989

A simple hemagglutination method for the detection of cell surface antigens.

A rapid, easy and reproducible hemagglutination method is described for the detection of cell surface antigens. This method can be used for the determination of cell subpopulations and the screening of monoclonal antibody-secreting hybridomas. Fresh or paraformaldehyde-fixed cells, which have previously been labeled with an appropriate monoclonal antibody (of known or unknown specificity), are reacted with human erythrocytes coupled with the second antibody (rabbit anti-mouse immunoglobulins), in a round bottomed 96-well microtiter plate. The presence of specific agglutination and the end-point of serial dilutions of the labeled cells with unlabeled ones give an approximate estimation of the percentage of cells reacting with the monoclonal antibody under examination. The hemagglutination results correlate well with the results obtained using a conventional immunofluorescence method.

Antibodies, Monoclonal↗