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Biomedical subjects

I Garcia

Publications and source records attributed to I Garcia.

At least 127 records · Page 7Linked to original sources
PubMed1992

Entry of lomefloxacin and temafloxacin into human neutrophils, peritoneal macrophages, and tissue culture cells.

The uptake of lomefloxacin (difluoroquinolone) and temafloxacin (trifluoroquinolone) by human polymorphonuclear leukocytes (PMNs), peritoneal macrophages (PM phis), and two tissue culture cells (McCoy and Vero) was measured by a fluorometric assay. Both antimicrobials reached high intracellular concentrations in PMNs [cellular to extracellular ratio (C/E) greater than 4], in PM phis (C/E greater than 3) and lower in tissue culture cells (C/E greater than 1) at an extracellular concentration of 5 mg/L. Lomefloxacin uptake by PMNs was more rapid than that of temafloxacin. Entry of both quinolones into PMNs was environmental temperature-dependent, but not affected by cell viability. Ingestion of opsonized Staphylococcus aureus did not affect the ability of PMNs to concentrate these antimicrobials. Ingestion of opsonized zymosan or stimulation with phorbol myristate acetate significantly increased the PMN association of both quinolones, this effect being particularly marked with temafloxacin. It is concluded that both lomefloxacin and temafloxacin are markedly concentrated within human phagocytes and tissue culture cells, although this phenomenon is not dependent on the degree of fluorination of the molecule.

Animals↗
PubMed1992

Randomized trial of chemotherapy versus chemotherapy plus radiotherapy for stage III-IV A & B Hodgkin's disease.

A total of 151 patients with previously untreated Hodgkin's disease, clinical stages III-IV A & B, were randomized to receive CVPP for 6 cycles, or CVPP plus RT 3000 cGy to previously involved areas between the 3rd and 4th cycles. CVPP consists of cyclophosphamide 600 mg/m2/i.v., vinblastine 6 mg/m2/i.v. on day 1, procarbazine 100 mg/m2/p.o. and prednisone 40 mg/m2/p.o. on days 1 to 14. Both groups displayed similar clinical characteristics at diagnosis. Sixty-six were treated with CVPP + RT (52 St III and 14 St IV) and 85 with CVPP alone (68 St III and 17 St IV). Complete remission was obtained in 57 (86%) of 66 patients who received CVPP plus RT, and in 62 (73%) of 85 patients treated with CVPP. Five and sixteen patients, respectively, achieved partial responses, while 2 in each group died during treatment. At 7 years, duration of complete remission and failure-free survival were: 51% and 45% for those treated with CVPP plus RT, and 23% and 21% with CVPP alone (p = 0.0150 and P = 0.0016, respectively). Overall survival at 7 years was 71% and 58%, respectively (p = 0.1488). A dose analysis performed in 84 pts showed that 91% and 88% received full protocol doses of CPM and PCZ, respectively, in the CVPP + RT group, and 95% and 94% for CVPP. The WBC nadir was 3.5 and 3.7 x mm3, respectively. Of 25 pts on CVPP + RT who relapsed, 9 are now disease-free, 5 are alive with disease and 11 have died, and with CVPP, of 37 relapsing pts, 18 are disease-free, 5 are alive with disease and 14 are dead.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Major bacterial infections following liver transplantation: a prospective study.

The incidence and characteristics of major bacterial infections were studied prospectively in 50 consecutive adult patients who underwent liver transplantation (LT). All patients received the same protocol of immunosuppression, bowel decontamination, antibiotics prophylaxis, and follow-up. Thirty-two patients (64%) had at least one episode of major bacterial infection. One death was directly related to a bacterial infection, accounting for 13% of postoperative mortality. The most critical period for infection was the first 2 months after surgery, when 69% of the infections occurred. The most frequent clinical presentations were bacteremia, pneumonia and abdominal abscesses. Eighty percent of the bacteremias had an identifiable source, the most frequent being intravascular catheters. Gram-positive microorganisms (69%) predominated over gram-negative rods (26%) and anaerobes (5%). The use of selective bowel decontamination (SBD) with norfloxacin may explain this predominance. Major bacterial infections are an important source of morbidity and mortality after LT. Efforts to prevent these infections and to determine their source and specific treatment, will improve the management and the outcome of these patients in the future.

Adult↗
PubMed1992

Beta-endorphin inhibits interleukin-2 release and expression of interleukin-2 receptors in concanavalin A-stimulated splenic lymphocytes.

beta-endorphin, when added at the same time as the mitogenic lectin concanavalin A to mouse BALB/c spleen lymphocytes, inhibits cell proliferation. The suppressive effect of beta-endorphin is not exercised through a cAMP-dependent mechanism and is also observed when splenic lymphocytes are stimulated with phytohemagglutinin (4 micrograms/ml), anti-CD3 monoclonal antibody, or the Ca2+ ionophore A23187 (250 nM) and phorbol 12-myristate 13-acetate (1 ng/ml). The inhibitory effect of beta-endorphin on lymphocyte proliferation is dose and time dependent: when beta-endorphin is added 20 h after Con A stimulation no suppression of lymphocyte proliferation is observed. beta-Endorphin inhibits, in a dose-dependent manner, the release of interleukin-2 in concanavalin A-stimulated splenic lymphocytes, measured 24 h after stimulation. beta-Endorphin also controls the appearance of interleukin-2 receptors in the plasma membrane, but does not regulate the expression of the c-myc protooncogene. These data indicate that beta-endorphin inhibits lymphocyte activation signal transmission, downstream the generation of the second messengers Ca2+ and diacylglycerol and the expression of the protooncogene c-myc, by blocking interleukin-2 release and interleukin-2 receptors expression. Once the cells are in the G1 stage, beta-endorphin is no longer able to block lymphocyte proliferation.

Animals↗
PubMed1991

Loss of heterozygosity for the short arm of chromosome 11 (11p15) in human milk epithelial cells immortalized by microinjection of SV40 DNA.

We have developed, by microinjection of SV40 DNA into human milk epithelial cells, a new mammary cell line, Hu-MI, which exhibits the phenotype of luminal cells or so-called "breast cancer precursor cells." This cell line retains the phenotype of primary cells as demonstrated by the expression of keratins 18 and 19 and of polymorphic epithelial mucins. However, the cells do not grow in agar after more than 80 passages, nor do they form tumors in nude mice. Established cells contain 2 copies of SV40 DNA integrated into the cellular genome and up to 14 copies of free SV40 DNA. A deletion of the short arm of chromosome 11 (11p15) including the c-Ha-ras and the beta-globin genes was found in the immortalized cells when the DNA from these cells was compared to the DNA from peripheral blood mononuclear cells obtained from the same donor. In addition, this cell line showed a good transfection efficiency for other DNA sequences using classical transfection and selection techniques with a neomycin resistance gene (pKOneo). Selective microinjection of DNA into tumor precursor cells may prove useful for the study of the molecular mechanisms involved in breast carcinogenesis. The possible significance of the loss of 11p13-15 in malignant progression of breast cancer is discussed.

Aneuploidy↗
PubMed1991

Evaluation of the fructosamine test in obesity: consequences for the assessment of past glycemic control in diabetes.

The effect of obesity in diabetic and nondiabetic states on serum fructosamine levels, as measured by the nitro blue tetrazolium reduction method, was investigated. In 26 nondiabetic obese subjects, the mean (SD) fructosamine (1.78 +/- 0.16 mmol/L) and protein corrected fructosamine concentrations (25.7 +/- 2.5 mumol/g) were significantly lower than in nondiabetic lean control subjects (2.06 +/- 0.18 mmol/L and 30.5 +/- 2.5 mumol/g, respectively; p less than 0.01). Hemoglobin A1C, blood glucose and serum protein concentrations were normal in obese subjects. Interference from hypertriglyceridemia, hemolysis, or drugs was excluded. In diabetic subjects, fructosamine correlated with hemoglobin A1C, but the least-squares regression lines were different in 16 nonobese and in 19 obese patients, so that for the same hemoglobin A1C value, fructosamine level was 16% lower in obese compared to nonobese diabetic subjects. In vitro studies showed a significant decrease in 14C-glucose incorporation in serum proteins of obese nondiabetic subjects compared to control subjects. Similarly, the rate of formation of fructosamine in sera of obese nondiabetic subjects incubated with 12 mmol/L and 30 mmol/L glucose concentrations was slower than in sera of control subjects. In conclusion, fructosamine is underestimated in obesity, both in diabetic and nondiabetic patients, and its validity as an index of glycemic control may be impaired in obese subjects. This decrease is due to an alteration in the glycation process itself.

Adult↗
PubMed1990

Further evidence for abnormal protein kinase C regulation of macromolecule secretion in fibroblasts from cystic fibrosis patients.

In comparison to skin fibroblasts from normal subjects, those from patients with cystic fibrosis (CF): (1) bound [20-3H] phorbol 12,13-dibutyrate (PDBu) with a higher affinity Kd = 25.8 vs 12.8 nM respectively) but expressed a similar number of total phorbol ester binding sites (about 2.5 pmol PDBu bound/mg of protein); (2) exhibited a faster and higher response to 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA) for the stimulation of [35S]-labelled glycoconjugate release, but were equally sensitive to the synergistic effect of A23187 on this process; and (3) secreted glycoconjugates with similar [35S]-sulfate and [14C]-leucine to [14C]-glucosamine labelling ratios. Taken together, these results provide further evidence for abnormal protein kinase C (PKC) regulation of macromolecule secretion in CF disease.

Binding Sites↗
PubMed1990

Uptake and intracellular activity of an optically active ofloxacin isomer in human neutrophils and tissue culture cells.

The penetration of an optically active ofloxacin isomer [(-)-ofloxacin] into human neutrophils and different tissue culture cells (HEp-2, McCoy, MDCK, and Vero) was studied and compared with that of ofloxacin by a fluorometric assay. The cellular-to-extracellular-concentration ratios (C/E) of (-)-ofloxacin were always higher than 6, significantly greater than those of ofloxacin at extracellular concentrations of 5 and 10 mg/liter. The penetration of (-)-ofloxacin and ofloxacin was doubled when neutrophils were stimulated by phorbol myristate acetate but not affected after ingestion of opsonized Staphylococcus aureus. The C/E ratios of (-)-ofloxacin and ofloxacin for different tissue culture epithelial cells and fibroblasts were lower than those of neutrophils but still higher than 2. Both compounds produced a significant reduction in viable intraphagocytic S. aureus during 3 h of exposure to antimicrobial agents. We conclude that (-)-ofloxacin appears to reach higher intracellular concentrations than ofloxacin, remaining active inside the neutrophils.

Cells, Cultured↗
PubMed1989

Genetic alterations of c-myc, c-erbB-2, and c-Ha-ras protooncogenes and clinical associations in human breast carcinomas.

We have analyzed genomic DNA sequences from 125 prospectively collected single unilateral primary breast carcinoma samples for the presence of alterations of c-myc, c-erbB-1, c-erbB-2, c-Ki-ras and c-Ha-ras protooncogenes. Amplification of the c-myc gene was found in 18% of the samples, and in one sample a non-germ line c-myc related DNA fragment or rearrangement was detected. We have found a significant association (P = 0.0010) between amplified c-myc gene and inflammatory carcinoma, a particularly aggressive breast cancer. The c-erbB-2 gene was amplified in 22% of the tumor samples and a rearrangement was observed once. Alteration of the c-erbB-2 gene was significantly linked to histological grade III tumors (P = 0.005) and the absence of estrogen and progesterone receptors (P = 0.036). No amplifications were observed for c-erbB-1, c-Ki-ras, and c-Ha-ras genes. About 40% of breast carcinomas contain either amplified c-myc or c-erbB-2 protooncogenes, whereas simultaneous amplification of both was seen in only one sample, suggesting the involvement of two distinct molecular mechanisms in breast cancer. Comparison of DNA from peripheral blood and tumor samples indicated loss of one c-Ha-ras allele in 29% of patients heterozygous for this polymorphism. A significant correlation (P = 0.016) between c-Ha-ras locus (11p14) allele loss and patient survival was found. These data suggest that 11p14 allelic loss plays a role in the evolution of human breast cancer, amplification of c-erbB-2 gene is associated with increasing stage of malignancy, and alteration of the c-myc gene in inflammatory breast carcinoma may contribute to the rapid progression of this human tumor subtype.

Blotting, Southern↗
PubMed1989

Production of monoclonal antibodies to dehydroepiandrosterone-sulphate after immunization of mouse with dehydroepiandrosterone-bovine serum albumin conjugate.

Monoclonal antibodies with a much higher specificity for DHA-S than for DHA were obtained from a BALB/c mouse immunized with a non-sulphated DHA-7CMO-BSA antigen. An improved fusion technique using PEG containing 10% DMSO instead of PEG alone increased the number of positive hybridomas. One of the five monoclonal antibodies obtained, showed a high affinity for DHA-S (Ka = 10(10) M-1) and very low cross-reactions with androsterone (0.62%) and androsterone sulphate (0.83%) which made it potentially useful for direct quantitation of DHA-S in human serum.

Animals↗
PubMed1989

Fluorometric measurement of ofloxacin uptake by human polymorphonuclear leukocytes.

A fluorometric assay, based on the natural fluorescence of the quinolone nucleus, was used to determine the uptake of ofloxacin by human polymorphonuclear leukocytes. The ratio of cellular concentration to extracellular concentration (C/E) at 20 min and 37 degrees C was 7.2, using an extracellular concentration of 5 micrograms/ml. Uptake was rapid and was not affected by pH (5 to 9), but required elevated environmental temperature and cell viability. The metabolic inhibitors sodium fluoride and sodium cyanide significantly decreased the uptake of ofloxacin. The penetration of ofloxacin was not affected by the presence of glucose or adenosine, but was decreased by L-amino acids (lysine, leucine, and glycine). These results suggest that ofloxacin could be transported via an amino acid transport system and that the fluorometric assay is a useful method for determining the intracellular penetration of fluoroquinolones, avoiding the use of radiolabeled antimicrobial agents.

Adenosine↗
PubMed1989

Inhibition of pancreatic exocrine secretion in the rat by calcitonin gene-related peptide: involvement of circulating somatostatin.

Calcitonin gene-related peptide (CGRP), a 37-amino acid peptide, has been shown to be a potent inhibitor of pancreatic exocrine secretion when administered exogenously The present study was performed to determine if this inhibitory effect is due to the direct actions of exogenous CGRP on the exocrine pancreas or to the effects of another inhibitor released by CGRP. To this end, we first confirmed the inhibitory effects of the peptide on exocrine function by infusing the peptide into conscious rats previously prepared with bile-pancreatic fistulas and measuring cholecystokinin-stimulated amylase and protein outputs. CGRP produced a dose-dependent inhibition of both protein and amylase outputs in vivo. In marked contrast, CGRP in vitro had no direct inhibitory effect on amylase output from either the isolated buffer-perfused pancreas or dispersed acinar cells. Thus, the inhibitory effects of exogenous CGRP on pancreatic exocrine function appear to be indirect. In an attempt to determine the mediator of the inhibitory effects of CGRP, we assessed the ability of similar doses of CGRP to stimulate the release of a potential endogenous inhibitor of pancreatic exocrine function, circulating somatostatin. In conscious rats, iv CGRP dose-dependently increased circulating plasma somatostatin-like immunoreactivity from 35 +/- 5 to 86 +/- 7 fmol/ml. To determine if these increments in circulating somatostatin were sufficient to impair exocrine function, the isolated pancreas was exposed in vitro to a similar concentration of somatostatin. Somatostatin perfusion resulted in a significant inhibition of pancreatic amylase output (73%). Overall, these results support the hypothesis that 1) the inhibitory effect of exogenous CGRP on pancreatic exocrine function is indirect; 2) exogenous CGRP stimulates the release of endogenous somatostatin into the systemic circulation; and 3) the concentration of circulating somatostatin is sufficient to mediate the effect of exogenous CGRP on the exocrine pancreas.

Amylases↗
PubMed1988

Randomized trial of chemotherapy versus chemotherapy plus radiotherapy for stage I-II Hodgkin's disease.

A total of 277 patients with untreated Hodgkin's disease, clinical stages I-II, were randomized to cyclophosphamide, vinblastine, procarbazine, and prednisone (CVPP) alone for 6 monthly cycles or to CVPP plus radiation therapy (RT), 3,000 rad, to involved areas (CVPP plus RT). One or more of the following factors were considered as unfavorable prognosis: age greater than 45 years, more than two lymph node areas involved, or bulky disease. In the favorable group, disease-free survival (77% vs. 70%) or overall survival (92% vs. 91%) at 84 months for CVPP versus RT plus CVPP was similar. Patients with unfavorable prognosis treated with RT plus CVPP had longer disease-free survival (75% vs. 34%) (P = .001) and overall survival (84% vs. 66%) than patients treated with CVPP alone.

Adolescent↗