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Biomedical subjects

N Perez

Publications and source records attributed to N Perez.

71 records · Page 4Linked to original sources
PubMed1992

Phase II study of the safety and efficacy of a 5-lipoxygenase inhibitor in patients with ulcerative colitis.

We examined the effects of an inhibitor of 5-lipoxygenase (A-64077) in 11 patients with mild to moderately active ulcerative colitis (UC). Treatment was a daily oral dose of 800 mg for 28 days. Physicians global rating (scale 1-50) included stool characteristics, rectal bleeding, abdominal and rectal pain, urgency, and general well being; sigmoidoscopic evaluation (scale 1-15) included mucosal vascular pattern, erythema, granularity/ulcerations, friability, and exudate. All of the patients experienced a decrease in discomfort of their disease, and the gross appearance in the sigmoidoscopy improved in eight of them, but were not accompanied by histologic improvement. No significant side effects occurred. A long-term controlled double-blind and dose-effect trial using 5-lipoxygenase inhibitors is needed which may lead to a new therapeutic approach in UC.

Administration, Oral↗
PubMed1991

Increased synthesis and accumulation of heat shock 70 proteins in Alzheimer's disease.

Postmortem cortical tissues from Alzheimer's disease cases were found to contain significantly higher levels of the heat shock proteins hsp 72 and hsp 73 than control cortical tissues. This elevation was associated with the disease pathology in that it was not observed in Alzheimer's disease cerebella and was not correlated with perimortem characteristics such as age or cause of death of the patient or postmortem interval of the brain tissue. Examination of polysome translation products on two dimensional gels and by immunoprecipitation indicated that the syntheses of hsp 72/73 were increased in Alzheimer's disease tissues. In addition, immunoprecipitation of newly synthesized hsp 72 showed that numerous other nascent polypeptides were co-precipitated, which indicates an irreversible cotranslational association with the hsp 72. These results indicate that induction of specific heat shock proteins is associated with Alzheimer's disease and that cotranslational processes are affected by this induction.

Aged↗
PubMed1989

Kinetic studies on the sialidase of three influenza B and three influenza A virus strains.

Sialidase of influenza virus type A has been extensively studied through structural and kinetic approaches. However, sialidase of influenza virus type B has been less investigated. In this work, we have studied the activity and some properties (optimal pH, KM, Vmax, thermal stability) of sialidase in three influenza virus strains of type B (circulating in the period 1983-86) and also the activity and properties of sialidase from three virus strains of type A circulating at the same period of time. The results show that the activity and the Vmax was always higher for sialidase of type A viruses relative to those values of type B. Differences were also found for optimal pH and, in some cases, for thermal stability of the sialidase between strains belonging to the influenza viruses type A and B. However, the behaviour for the sialidase in all strains was very similar towards two competitive inhibitors. Thus, it could be suggested that the evolution pattern of the sialidase of both types of influenza viruses determines some modifications which result in a higher efficiency for sialidase of some strains of influenza virus type A, but maintaining in the two types of viruses a similar behaviour towards competitive inhibitors.

Animals↗
PubMed1989

In vivo infusion of anti LFA-1 antibody in HLA non-identical bone marrow transplantation in children: serum concentrations and biological effects.

The mouse monoclonal antibody 25-3 specific for the alpha subunit of LFA-1 (CD11a) has been infused to children undergoing HLA non-identical bone marrow transplantation because of lethal inherited diseases or of leukemia in order to prevent graft failure. We have assessed the serum concentrations of the antibody infused according to two regimens: 0.1 mg/kg five times, every alternate day (eight patients) or 0.2 mg/kg daily for 10 days (30 patients). Serum trough levels of 25-3 antibody in the first group were constantly found to be low (less than 0.6 micrograms/ml) while 25-3 serum concentration in the second group rose progressively to a mean value of 2.2 micrograms/ml. Serum antibody concentrations were significantly lower in patients with greater antigenic mass, i.e. with splenomegaly, or non conditioned. The engraftment rate was slightly higher in patients treated by the daily infusion of 25-3 for 10 days. No immunization against 25-3 antibody occurred. One patient who subsequently received other mouse anti-B cell antibodies eventually produced anti-isotype antibodies. The consequences of 25-3 infusion on leukocyte counts has been evaluated in the group of patients (n = 6) with severe combined immunodeficiency who did not receive any chemotherapy and in one who was treated with 25-3 because of acute graft-versus-host disease. In none of the cases did 25-3 antibody infusion modify blood leukocyte counts. In addition, it was shown that saturation of LFA-1 on leukocytes was a transient phenomenon, since it could not be found 24 h following infusion of 25-3 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1985

Treatment of four patients with erythrophagocytic lymphohistiocytosis by a combination of epipodophyllotoxin, steroids, intrathecal methotrexate, and cranial irradiation.

Familial erythrophagocytic lymphohistiocytosis, a rare disorder affecting infants, is characterized by a visceral infiltration of histiocytes and lymphocytes resulting in rapid death. It has recently been reported that use of epipodophyllotoxin, VP 16-213, could induce a complete remission of the disease. Such treatment does not, however, prevent fatal CNS relapse. Four patients with the characteristic features of the disease--fever, hepatosplenomegaly, pancytopenia, low plasmatic fibrinogen level, hyperlipidemia, and histiocytic meningitis--are described. These patients were treated with a combination therapy including systemic administration of VP 16-213, steroids, and intrathecal methotrexate followed by cranial irradiation after the age of 12 months. The four patients achieved complete remission of the disease after clearing of the CNS localization. Two patients had secondary relapses, but all four patients have had a disease-free survival exceeding 12 months. All patients have been in remission of the disease for 27, 20, 16, and 13 months, respectively, after disease onset without major setbacks from the treatment. This combination therapy appears to be a promising approach toward long-term remission of the disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Pure interferon gamma enhances class II HLA antigens on human monocyte cell lines.

Human recombinant interferon gamma (IFN-gamma) with a chemical purity of over 90% was shown to enhance membrane expression of HLA-DR antigens on cells from 3 human myelomonocytic lines (HL-60, U-937 and THP-1). Immunofluorescence techniques using a series of anti-HLA-DR monoclonal antibodies showed that the low, although variable, levels of DR-positive cells were clearly enhanced as soon as 24 h after incubation with IFN-gamma. Only IFN-gamma was able to exert this effect, since incubation with high concentrations of IFN-alpha or -beta did not induce any significant modification of the percentage of HLA-DR-positive cells. In contrast, doses of IFN-gamma as low as 2 units were effective, indicating a highly preferential, apparently selective effect of IFN-gamma for enhancement of HLA-DR expression. Private class II antigen expression was also enhanced by IFN-gamma on the U-937 cell line. Through its enhancing effect on class II public and private HLA antigens on the membrane of human monocytes, the IFN-gamma lymphokine may have a critical role in the modulation of antigen presentation by monocytes and on the regulation of HLA-DR-restricted cell cooperation.

Antibodies, Monoclonal↗
PubMed1984

Impaired natural killer activity in lymphohistiocytosis syndrome.

In six patients with well-documented lymphohistiocytosis syndrome, natural killer activity was found to be profoundly impaired and could not be increased by incubation in vitro with interferon. This abnormality was not found in parents of the affected children. A clear correlation with the activity of the disease was observed, although a delay of a few weeks (possibly reflecting the life span of NK cells in blood) was seen in the disappearance of NK activity after the onset of the disease and its reappearance after remission. No absolute correlation was observed between NK activity and percentage of leukocytes detected by the Leu-7 monoclonal antibody. Our findings indicate that testing NK activity is useful for the diagnosis of lymphohistiocytosis syndrome and can be used as an index of activity of the disease, among other major clinical and biologic signs of this syndrome. Reversal of the NK activity defect (rather than detection of Leu-7 positive cells) appears to be a good criterion of complete remission.

Antibodies, Monoclonal↗
PubMed1983

Bone-marrow transplantation for inborn error of phagocytic cells associated with defective adherence, chemotaxis, and oxidative response during opsonised particle phagocytosis.

Two girls had delayed umbilical cord detachment, recurrent bacterial infection, inability to form pus, and marked leucocytosis. Their phagocytes were defective in tests of adherence, random migration, chemotaxis, and oxidative burst. NK activity was virtually absent. This rare disorder, due to an inherited absence of a 180 kilodalton membrane glycoprotein on polymorphonuclear cells, is usually lethal within 2 years. Allogeneic HLA-matched bone-marrow transplantation done at ages 4 months in one patient and 2 years in the other after intensive conditioning was successful and resulted in nearly complete correction of phagocytic cell function and NK activity within two months. One patient died 9 months after transplantation from severe chronic graft-versus-host disease with obstructive bronchopneumopathy. The other is doing well 1 year after transplantation and showing stable chimerism and normal phagocytic function.

Bone Marrow Transplantation↗
PubMed1982

Studies on neuraminidase from influenza virus A(H3N2) obtained by two procedures.

1. Neuraminidase was obtained by (A) bromelain solubilization or (B) by treatment with N-lauroylsarcosine. 2. 5-N-acetyl-2-O-(3-methoxyphenyl)-alpha-D-neuraminic acid, employed as substrate, avoids the interference produced by the thiobarbituric acid method, and is not interfered by the ampholytes. 3. Only about 20% of original enzyme activity was lost after electrofocusing. The sample from procedure A showed two peaks, corresponding to pIs 4.4 and 5.6. The sample from procedure B, having a higher activity, showed only one peak at pI 4.4. 4. Samples A and B showed different Km and hydrolysis rate with N-acetylneuraminyl-lactose and glycophorin A. It was not found significantly different with other substrates: alpha 1-acid glycoprotein, brain gangliosides, 5-N-acetyl-2-O-(3-methoxyphenyl)-alpha-D-neuraminic acid and 2'-(4-methyl umbelliferyl)-alpha-D-N-acetylneuraminic acid.

Amino Acids↗
PubMed1981

Modification of sister chromatid exchanges and radiation-induced transformation in rodent cells by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate and two retinoids.

Modification of sister chromatid exchanges and radiation-induced transformation in mouse C3H/10T 1/2 and Syrian hamster embryo cells by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate and two retinoids, the trimethylmethoxyphenyl analog of N-ethyl retinamide and beta-all-trans-retinoic acid, has been studied. 12-O-tetradecanoylphorbol-13-acetate alone enhances, and retinoids alone reduce radiation-induced transformation. When both compounds were present, the retinoids not only reduced the oncogenic effects of radiation but completely eliminated the promoting effects of 12-O-tetradecanoylphorbol-13-acetate. These results were not paralleled by changes in sister chromatid exchange frequencies, indicating that, while sister chromatid exchanges may be useful as indicators of primary carcinogen mutagens, they may have little utility when secondary agents after the response of cells to a primary initiator.

Animals↗
PubMedDate not supplied

Mechanical thrombectomy in patients with deep venous thrombosis.

PURPOSE: To report our experience with mechanical thrombectomy in proximal deep vein thrombosis (DVT). METHODS: Eighteen patients with a mean (+/- SD) age of 37.6 +/- 16.1 years who presented with DVT in the iliac and femoral vein (n = 3), inferior vena cava (n = 5), or inferior vena cava and iliac vein (n = 10), were treated with the Amplatz Thrombectomy Device after insertion of a temporary caval filter. RESULTS: Successful recanalization was achieved in 15 of 18 patients (83%). Overall, the percentage of thrombus removed was 66 +/- 29%: 73 +/- 30% at caval level and 55 +/- 36% at iliofemoral level. Complementary interventions (seven patients) were balloon angioplasty (n = 2), angioplasty and stenting (n = 2), thrombo-aspiration alone (n = 1), thrombo-aspiration, balloon angioplasty, and permanent filter (n = 1), and permanent filter alone (n = 1). There was one in-hospital death. Follow-up was obtained at a mean of 29.6 months; three patients had died (two cancers, one myocardial infarction); 10 had no or minimal sequelae; one had post-phlebitic limb. CONCLUSION: Mechanical thrombectomy is a potential therapeutic option in patients presenting with proximal DVT.

Adult↗
PubMedDate not supplied

Spiral CT quantification of aorto-renal calcification and its use in the detection of atheromatous renal artery stenosis: A study in 42 patients.

PURPOSE: To investigate whether a correlation exists between aortic and renal arterial calcifications detected with spiral CT and significant angiographic renal artery stenosis (RAS). METHODS: Forty-two patients (mean age 67 years, range 37-84 years), of whom 24 were hypertensive, prospectively underwent abdominal helical CT and aortic and renal arteriography. The 3-mm thickness CT scans (pitch = 1) were reconstructed each millimeter. A manual outline of the renal artery including its ostial portion was produced. Calcific hyperdensities were defined as areas of density more than 130 HU. CT data were compared with the presence or absence of RAS on angiography (24 cases); hypertension and age were taken into account (Mann-Whitney U-test). RESULTS: CT detection and quantification appeared to be reliable and reproducible. We did not find any correlation between aortic and renal arterial calcifications and RAS, even for the patients above 65 years, with or without hypertension. There was no correlation either between calcifications and hypertension in patients without RAS. CONCLUSION: In this population, aortic and renal arterial calcifications have no predictive value for RAS.

Aged↗
PubMedDate not supplied

Prospective study of the enzymatic activities in urine of N-acetyl-beta-D-glucosaminidase, alpha-D-mannosidase, alpha- and beta-D-glucosidases, alpha-L- and beta-D-fucosidases, and beta-D-galactosidase in type I diabetes mellitus with early nephropathy.

Different surveys have been carried out on the plasma activities of different glycosidases in patients with insulin-dependent diabetes mellitus, but research on urinary glycosidases in this disease is scanty and incomplete. To elucidate the behavior of these lysosomal enzymes in the metabolic alterations occurring in the glomerular basal membrane during the initial stages of diabetic nephropathy, we conducted a prospective study to examine the urinary activities of N-acetyl-beta-D-glucosaminidase (NAG), alpha-D-mannosidase, alpha- and beta-D-glucosidase, alpha-L- and beta-D-fucosidase, and beta-D-galactosidase in patients with type I insulin-dependent diabetes mellitus, surveyed over 18 months, whose early diabetic nephropathy was detected by the presence of microalbuminuria. The simultaneous determination of beta 2-microglobulin in urine confirmed the glomerular origin of the albuminuria. No statistically significant correlation was found between the levels of albuminuria and the activities of any of the glycosidases analyzed. In the diabetic patients, a significant decrease was observed in the activities of all the enzymes (p < 0.05), except NAG and alpha-D-mannosidase, although the decrease in the latter was very close to statistical significance (p = 0.028, unilateral; p = 0.057 bilateral). Similarly, in the patients, there was a significant negative correlation (p < 0.05) with the serum levels of fructosamine, except with beta-D-galactosidase, which showed a positive correlation (p < 0.05) with fructosamine and blood HbA1c.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗