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Biomedical subjects

I García

Publications and source records attributed to I García.

At least 19 recordsLinked to original sources
PubMed1996

Case report: pulmonary blastoma in children--response to chemotherapy.

Pulmonary blastoma (PB) is a rare primary malignancy of the lung, with about 54 cases reported in children. The tumor consists of mesenchymal and epithelial components resembling the fetal lung. It has been treated primarily with surgery and the effect of combination chemotherapy has not been systematically investigated. A 15-year-old girl with PB with metastases to bone and regional lymph node, and high levels of alphafetoprotein, is reported. A preoperative combination chemotherapy consisting of cisplatinum, etoposide alternating with iphosphamide with mesna, vincristine and epirubicine resulted in an objective response that permitted subsequent safe surgical excision of the primary tumor. This intensive combination chemotherapy should be tested in the management of advanced PB in children, as initial therapy as well as an adjuvant to surgery.

Adolescent↗
PubMed1996

[Intracellular penetration of 5 quinolones into non-phagocytic cells].

BACKGROUND: The intracellular penetration and activity of antimicrobial agents can be an important factor in the treatment of infections caused by intracellular pathogens. The new quinolones are able to penetrate into phagocytes, but only a few studies have evaluated other types of cells. The purpose of this study is to evaluate the intracellular penetration of ofloxacin, levofloxacin, lomefloxacin, sparfloxacin and BAY Y 3118 into human polymorphonuclear leukocytes and tissue cultured epithelial cells. METHODS: Intracellular penetration was evaluated by a fluorometric assay for all the quinolones evaluated except for sparfloxacin, which was evaluated by a radiometric assay. RESULTS: All the quinolones evaluated reached intracellular concentrations higher than extracellular ones. The penetration of sparfloxacin and BAY Y 3118 into the epithelial cells was similar to those observed for PMNs (cellular to extracellular concentration ratio; C/E > or = 4). The C/E values of ofloxacin, levofloxacin and lomefloxacin for epithelial cells were lower than those observed in PMN, but still yielding C/E values > or = 2.

Cells, Cultured↗
PubMed1996

Anaphylaxis to subcutaneous neutral protamine Hagedorn insulin with simultaneous sensitization to protamine and insulin.

We report an insulin-treated diabetic patient who suffered, in a 2-month period, three severe anaphylactic reactions immediately after self-administered subcutaneous injections of neutral protamine Hagedorn (NPH) human recombinant-DNA insulin. These reactions consisted of local and systemic symptoms, including dyspnea and hypotension. A simultaneous sensitization to human insulin and to protamine was demonstrated, both by skin tests and by the determination of serum specific IgE. Suspecting protamine allergy, we performed a test dose to human lente insulin with perfect tolerance. After a 1-year follow-up with lente-insulin treatment, no reactions have occurred, despite treatment interruptions. Therefore, protamine IgE-mediated allergy probably caused our patient's reactions. In conclusion, protamine sensitization should be ruled out in any patient with a history of reactions to subcutaneous protamine-containing insulins, even if insulin sensitization is present.

Adult↗
PubMed1995

Down-regulation of tumor necrosis factor receptors by blockade of mitochondrial respiration.

We have studied the effect of blockade of mitochondrial respiration on the binding of human 125I-TNF alpha to L929 cell receptors. Specific TNF alpha binding was decreased to about 20-40% of controls by blocking mitochondrial respiration. This effect was dose- and time-related and was observed independently of the level at which the respiration was blocked (respiratory chain, proton backflow, ATPase, anaerobiosis). This blockade had no effect on the half-life of the specific TNF alpha binding, the internalization or degradation of TNF alpha-receptor complexes, or the number of TNF alpha-binding sites. Scatchard analysis of TNF alpha binding data indicated a 2-4-fold decrease in the affinity of these binding sites. These effects did not appear to be related to the protein kinase C activity or to reactive oxygen radicals, since they were not antagonized by pretreatment of cells with oxygen radical scavengers, deferoxamine, or inhibitors of protein kinase C. Decrease in TNF alpha binding capacity correlated significantly with cellular ATP content (r = 0.94; p < 0.01) and with the cytocidal activity of TNF alpha against L929 cells. These findings suggest that blockade of mitochondrial respiration down-regulates the binding of TNF alpha to cells, most likely by changing the affinity of receptors for this cytokine. This down-regulation may increase the resistance of cells to TNF alpha cytotoxicity.

2,4-Dinitrophenol↗
PubMed1995

bcl-x is expressed in embryonic and postnatal neural tissues and functions to prevent neuronal cell death.

Previous studies have implicated the bcl-2 protooncogene as a potential regulator of neuronal survival. However, mice lacking functional bcl-2 exhibited normal development and maintenance of the central nervous system (CNS). Since bcl-2 appears dispensable for neuronal survival, we have examined the expression and function of bcl-x, another member of the bcl-2 family of death regulatory genes. Bcl-2 is expressed in neuronal tissues during embryonic development but is down-regulated in the adult CNS. In contrast, Bcl-xL expression is retained in neurons of the adult CNS. Two different forms of bcl-x mRNA and their corresponding products, Bcl-xL and Bcl-x beta, were expressed in embryonic and adult neurons of the CNS. Microinjection of bcl-xL and bcl-x beta cDNAs into primary sympathetic neurons inhibited their death induced by nerve growth factor withdrawal. Thus, Bcl-x proteins appear to play an important role in the regulation of neuronal survival in the adult CNS.

Aging↗
PubMed1995

Primary structure and expression pattern of the 33-kDa chitinase gene from the mycoparasitic fungus Trichoderma harzianum.

A gene (chit33) from the mycoparasitic fungus Trichoderma harzianum, coding for a chitinase of 33 kDa, has been isolated and characterized. Partial amino-acid sequences from the purified 33-kDa chitinase were obtained. The amino-terminal peptide sequence was employed to design an oligonucleotide probe and was used as a primer to isolate a 1.2-kb cDNA. The cDNA codes for a protein of 321 amino acids, which includes a putative signal peptide of 19 amino acids. All microsequenced peptides found in this sequence, indicate that this cDNA codes for the 33-kDa chitinase. A high homology (approximately 43% identity) was found with fungal and plant chitinases, including yeast chitinases. However enzyme characteristics suggest a nutritional (saprophytic or mycoparasitic), rather than a morphogenetic, role for this chitinase. The chit33 gene appears as a single copy in the T. harzianum genome, is strongly suppressed by glucose, and de-repressed under starvation conditions as well as in the presence of autoclaved mycelia and/or fungal cell walls. The 33-kDa chitinase seems to be very stable except under starvation conditions. The independent regulation of each of the chitinases in T. harzianum indicates different specific roles.

Amino Acid Sequence↗
PubMed1995

Factors affecting the intracellular accumulation and activity of azithromycin.

Azithromycin is a new macrolide which accumulates in high concentrations in human phagocytes. The cellular to extracellular ratio (C/E) of azithromycin concentrations (fixed extracellular concentration 1 mg/L) in human polymorphonuclear leucocytes (PMN) were significantly affected by small increases in the environmental temperature (C/E 20.3 +/- 2 and 59.4 +/- 6 at 37 degrees C and 40 degrees C, respectively). PMN-associated azithromycin was not affected by the presence of different concentrations of human serum. The intracellular accumulation of azithromycin decreased slightly (C/E approximately 5) when cells were activated with PMA or opsonized with zymosan. The phagocytosis of opsonized Staphylococcus aureus or Haemophilus influenzae, however, slightly increased the intracellular concentrations of azithromycin. At different extracellular concentrations, azithromycin did not affect the production of hydrogen peroxide and superoxide radicals by PMN. The intracellular survival of H. influenzae in human PMN was abolished in the presence of concentrations higher than 0.125 mg/L of azithromycin. Under the same experimental conditions, however, azithromycin did not show any intracellular activity against S. aureus.

Azithromycin↗
PubMed1995

Activity of sparfloxacin on Staphylococcus epidermidis attached to plastic catheters.

The activity of sparfloxacin on Staphylococcus epidermidis biofilms on different plastic catheters was evaluated. Sparfloxacin showed high bactericidal activity against S. epidermidis biofilms on Vialon and polyvinylchloride catheters. The combination of sparfloxacin with amikacin or rifampicin significantly increased its activity against bacterial biofilms on polyurethane and Teflon catheters.

Amikacin↗
PubMed1995

[Liver transplantation using grafts from donors over 65].

OBJECTIVE: Donors age 50 years was an exclusion criteria in past decades. The increase of patients in the waiting list has determined the acceptance of older donors (over 65 years old). We analyze our results in liver transplantation using donors over 65 years. PATIENTS: From 1986 to may 1994, we performed 381 OLT. In five cases (1.3%) the OLT was performed using donors over 65 years of age (66, 67, 68, 70 and 71). The selection criteria for donors and recipients were similar to the other transplanted patients. Immunosuppression included cyclosporine or FK-506, prednisone and azathioprine. RESULTS: There were no primary graft failures and preservation damage, biochemical and clinical evolution were not different to the procedures using younger donors. Three grafts presented non-corticoresistant acute rejection. After a follow-up of 11.6 mo (range 4-37 mo) only one graft was lost (Kaposi's sarcoma in the liver). Four grafts and four patients are in excellent biochemical and clinical condition. CONCLUSIONS: Donor age should not be an exclusion criteria. Grafts from older donors (over 65 years old) may be considered safe and will permit to increase the number of OLT.

Adult↗
PubMed1994

Stage III abdominal non-Hodgkin's lymphoma in Costa Rican children: comparison of two consecutive trials of treatment.

Seventy-three patients with Stage III abdominal non-Hodgkin's lymphoma were prospectively treated following two sequential protocols (P): L278 P (group A, 33 patients) (1978-1983) and L384 P (group B, 40 patients), (1984-1991). No patient received radiotherapy. The L278 P included 7 drugs: cyclophosphamide, vincristine (VCR), adriamycin (ADR), prednisone, methotrexate (MTX), dexamethasone, and 6-mercaptopurine, given for remission induction, maintenance, and CNS prophylaxis. In the L384 P we introduced a consolidation phase consisting of intravenous MTX and citrovorum factor rescue, and IV cytosine arabinoside. VCR was also added to the monthly doses and the maintenance phase was reduced from 18 to 15 months. From January 1988 we changed ADR for epirubicin in the same doses. Prophylactic treatment of the CNS, in the L384 P, was intensified by increasing the number of doses of MTX IT in the remission, induction, and consolidation phases, and with the use of ara-C IT. Laparotomy in 50 patients allowed partial resection in 16, and second-look laparotomy was performed in 27 patients. Viable tumor was found in four patients. Three patients (G-A) died from metabolic complications and another 4 (2 G-A and 2 G-B) failed to attain CR and died. A total of 28 (85%) of 33 children of G-A and 38 (95%) of 40 children in G-B achieved CR. Five children died in remission (2 G-A, 3 G-B). Three patients (G-A) relapsed in the CNS and one (G-B) relapsed in the abdomen and died. Disease-free survival at 120 months was 70% in G-A and 84% in G-B.

Abdominal Neoplasms↗
PubMed1994

Pediatric Hodgkin's disease in Costa Rica: twelve years' experience of primary treatment by chemotherapy alone, without staging laparotomy.

This is a prospective and nonrandomized study in which 86 children with previously untreated Hodgkin's disease (HD) were clinically staged (CS) and treated with chemotherapy (CT) alone. Fifty-two (CS IA-38, IIA-7, IIB-3, IIIA-4) received six courses of cyclophosphamide, vinblastine, procarbazine, and prednisone (CVPP). Ten (CS IA with peripheral nodes) received only three courses of CVPP with a reinforcement of C on day 8. Twenty-four (CS IIIB-18, IVA-2, IVB-4) received six courses of CVPP alternating with six courses of epirubicin, bleomycin, and vincristine (EBO). Surgical staging was not performed in any patient. Two patients (CS IIIB) had partial remission and died from progressive disease. Seventy out of 86 children have not relapsed and are in complete remission with a median follow-up of 65 months (range 13-156 months); 14 children relapsed seven to 37 months from diagnosis (median 16 months); one of them (IV B) died of disease. Thirteen are in second and third remission (median 55 months). Actuarial five year survival rates and relapse-free survival rates are 100% and 90% for CS I to IIIA and 81% and 60% for CS IIIB and IV, respectively. As a result of this study, we can conclude that in developing countries most of the children with HD staged by noninvasive diagnostic techniques can be cured with CT alone as primary treatment and thus will not suffer from the late effects of radiotherapy (RT) and the morbidity of laparotomy and splenectomy. RT alone or with other CT combinations should be considered for children who develop relapse of HD.

Adolescent↗
PubMed1994

Cloning and characterization of a chitinase (chit42) cDNA from the mycoparasitic fungus Trichoderma harzianum.

A cDNA of Trichoderma harzianum (chit42), coding for an endochitinase of 42 kDa, has been cloned using synthetic oligonucleotides corresponding to amino-acid sequences of the purified chitinase. The cDNA codes for a protein of 423 amino acids. Analysis of the N-terminal amino-acid sequence of the chitinase, and comparison with that deduced from the nucleotide sequence, revealed post-translational processing of a putative signal peptide of 22 amino acids and a second peptide of 12 amino acids. The chit42 sequence presents overall similarities with filamentous fungal and bacterial chitinases and to a lesser extent with yeast and plant chitinases. The deduced amino-acid sequence has putative catalytic, phosphorylation and glycosylation domains. Expression of chit42 mRNA is strongly induced by chitin and chitin-containing cell walls and is subjected to catabolite repression. Southern analysis shows that it is present as a single-copy gene in T. harzianum. chit42 is also detected in several tested mycoparasitic and non-mycoparasitic fungal strains.

Amino Acid Sequence↗
PubMed1994

Intracellular penetration and activity of BAY Y 3118 in human polymorphonuclear leukocytes.

The penetration of a new quinolone (BAY Y 3118) into human polymorphonuclear leukocytes (PMNs) was evaluated by a fluorometric assay. The cellular concentration-to-extracellular concentration (C/E) ratio was higher than 6.3 at extracellular concentrations ranging from 2 to 100 mg/liter. The uptake of BAY Y 3118 was rapid, reversible and nonsaturable. The intracellular penetration of BAY Y 3118 was significantly affected by environmental temperature (C/E ratio at 4 degrees C, 5.4 +/- 0.5; control, 7.5 +/- 0.9; P < 0.05) and cell viability (C/E ratio in dead PMNs, 5.5 +/- 0.8; control 7.5 +/- 0.9; P < 0.05), but it was not affected by metabolic inhibitors. The ingestion of opsonized zymosan or opsonized Staphylococcus aureus significantly decreased the levels of PMN-associated BAY Y 3118. Cell stimulation by a membrane activator, however, significantly increased the intracellular concentration of this quinolone. At therapeutic extracellular concentrations (0.5, 2, and 5 mg/liter), BAY Y 3118 showed intracellular activity greater than that of ciprofloxacin against S. aureus in human PMNs. It was concluded that BAY Y 3118 reaches high intracellular concentrations within human PMNs and remains active intracellularly.

Anti-Infective Agents↗
PubMed1994

[Laparoscopic gastrostomy].

Feeding gastrostomy is a method for treating patients unable to ingest food orally. After our experience and good results with the Janeway technique, we decided to perform it by the laparoscopic method. Our first excellent results in seven patients suggest that laparoscopic Janeway gastrostomy is an easy, rapid and efficient surgical technique.

Aged↗