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Biomedical subjects

I García

Publications and source records attributed to I García.

At least 145 records · Page 8Linked to original sources
PubMed1993

[Functioning tumors of the adrenal cortex in children. Clinical and therapeutic considerations on 11 cases].

In the last 20 years, eleven children with adrenocortical functional tumors were treated in the National Children Hospital of Costa Rica. There were nine females and two males and their ages ranged from nine months to 14 years. Eleven patients had features of virilism, five had stigmas of Cushing's syndrome and three hyperaldosteronism. The clinical diagnosis was established given the symptoms, hormonal tests and radiological and imagenological studies. The histologic diagnosis was carcinoma in six by clinical picture in one, and were adenoma in four. Three patients had regional and distant metastases. Four patients with carcinoma were treated by surgery and five received chemotherapy, two of them in presurgical stage, and four received radiotherapy. Two patients with carcinoma are alive and had no evidence of tumor recurrence ten and six years after diagnosis. Five are dead, two of them after partial response to chemotherapy. The four patients with adenoma were cured by complete surgical tumor resection, furthermore one of them received chemotherapy because there was not sure of his histologic benign condition. It is necessary more studies in use of chemotherapy in treatment of this tumors but in our experience CFM, VCR, Epi and Actin is a regimen that appears to be an active combination for the treatment in presurgical stage of adrenal cortical carcinoma.

Adolescent↗
PubMed1992

[Prospective study of cytomegalovirus infection in liver transplant recipients].

BACKGROUND: Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality in liver transplant recipients. The aim of this study was to determine the incidence, clinical characteristics, risk factors and response to treatment of CMV infection in liver transplant recipients. METHODS: Fifty-nine adult patients who underwent a liver transplant in our hospital were prospectively studied. Cell cultures were used to document CMV infection and disease. Ganciclovir treatment was only given to patients with documented CMV disease. RESULTS: Active infection was shown in 47 of 59 patients (80%), and symptomatic infection (disease) in 17 (29%). The most frequent clinical presentation was hepatitis (9 cases) followed by flu-like syndrome (6 cases) and pneumonitis (4 cases). The average time from transplant to the diagnosis of CMV disease was 36 days. The seronegative recipients of seropositive donors developed symptomatic infection more frequently (66%) than other patients (p < 0.05). As well as the CMV serologic status before transplantation, the use of anti-OKT3 antibodies was the only risk factor related to CMV disease (p < 0.01). The treatment with ganciclovir was successful in 17 of 19 symptomatic episodes. CONCLUSIONS: Active and symptomatic CMV infection in recipients of liver transplantation were very frequent in our study. The transplant from seropositive to seronegative and the use of anti-OKT3 antibodies increased the incidence of CMV disease. Ganciclovir appeared as a safe and, apparently, highly efficient drug.

Adult↗
PubMed1992

Insulin-like growth factor-I inhibits apoptosis in IL-3-dependent hemopoietic cells.

The death of hemopoietic cells on withdrawal of CSF occurs by a mechanism known as apoptosis characterized by the early degradation of chromatin into oligonucleosome-length fragments. Insulin-like growth factor I plays a pivotal role in the regulation of somatic cell growth as a mediator of growth hormone action. Animals with low levels of circulating IGF-I are more vulnerable to infections and have diminished immune responses. To analyze the possibility of a regulatory role of IGF-I on hemopoiesis and determine its mechanism of action, we have studied the effect of this growth factor on the survival and proliferation of two IL-3-dependent hemopoietic cell lines and in IL-3-responsive primary cultures of bone marrow-derived mast cells. In IL-3-depleted cultures, IGF-I prevented DNA fragmentation and apoptotic cell death. Insulin at high concentration had a weak protective action and IGF-II was inactive in suppressing apoptosis in these IL-3-dependent hemopoietic cells. Cell proliferation was also stimulated by IGF-I in the absence of other hemopoietic growth factors although it was a weak mitogen when compared with IL-3. These results indicate that circulating or locally produced IGF-I may promote survival of both the steady state hemopoietic precursor population and cytokine-producing cells and could therefore regulate hemopoiesis acting in a concerted manner with other CSF.

Animals↗
PubMed1992

Comparative penetration of lomefloxacin and other quinolones into human phagocytes.

The penetration of lomefloxacin into human polymorphonuclear leukocytes (PMNs) and peritoneal macrophages (PMphis) was evaluated using a fluorometric assay. Lomefloxacin reached high intracellular concentrations into PMNs at extracellular concentrations of 2 and 5 mg/L (cellular to extracellular concentration ratio [C/E] greater than 4). At the same conditions (20 minutes incubation; extracellular concentrations: 2 mg/L) lomefloxacin uptake by human PMNs (C/E: 7.9 +/- 2.6) was slightly higher than those of norfloxacin (C/E 5.1 +/- 1.8), ciprofloxacin (C/E: 6.2 +/- 2.0), and ofloxacin (C/E 7.1 +/- 2.6). Lomefloxacin penetration into human PMphis was significantly lower than PMNs but still with C/E ratios greater than 4. Entry of lomefloxacin into phagocytes was not affected by cell viability but was environmental-temperature dependent. It is concluded that lomefloxacin and the other quinolones evaluated reach high intracellular concentrations in human phagocytic cells.

Analysis of Variance↗
PubMed1992

Effect of several antimicrobial agents on ciprofloxacin uptake by human neutrophils.

The effect of antimicrobial agent active against anaerobes, gram-positive cocci and fungi on the uptake of ciprofloxacin by human neutrophils (PMNs) was evaluated. In the presence of therapeutic extracellular concentrations of these agents, ciprofloxacin reached high intracellular concentrations [cellular-to-extracellular ratio (C/E) greater than or equal to 2.9], this value being higher in the presence of amphotericin B (C/E 6.3 +/- 0.9). The intracellular penetration of ciprofloxacin was higher when PMNs were stimulated with opsonized zymosan (C/E greater than or equal to 5.6). In summary, none of the antimicrobial agents tested significantly impaired the uptake of ciprofloxacin by human PMNs.

Anti-Infective Agents↗
PubMed1992

Liver transplantation in malignant primary hepatic neoplasms.

Between April 1986 and August 1990, 151 liver transplantations were performed at our institution, 16 (11%) of them in 14 patients with primary hepatic tumors. There were 12 hepatocellular carcinomas, 1 angiosarcoma, and 1 Klatskin tumor. None of the tumors was resectable, and there was no preoperative evidence of extrahepatic tumoral extension. Exploratory laparotomy was performed prior to transplantation in three patients and selective embolization of the tumor in six patients. There was no difference in the intraoperative requirements for blood or plasma in the patients with hepatic tumors when compared with other transplant recipients (28.6 +/- 23.6 units packed red blood cells [PRBC] versus 20.1 +/- 17.8 units PRBC, and 17.9 +/- 12.2 units plasma versus 17.1 +/- 10.5 units plasma, respectively). Extracorporeal venovenous bypass was used in all but one patient. There was no significant differences in the incidence of acute rejection or in the length of hospitalization in these patients when compared with other transplant recipients. All patients received triple immunosuppressive therapy (corticosteroids, azathioprine, and cyclosporin A). Intraoperative mortality was zero. At a mean of 13.3 months' follow-up (range: 1 to 47 months), 2 of 14 patients had died of sepsis and 1 of terminal cirrhosis (autopsies revealed no evidence of tumor recurrence); 3 patients (21%) had recurrences of the tumor (1 in the central nervous system and liver, and the other 2 in the lung). One of the three patients with a recurrent tumor is still alive after 16 months. The remaining nine patients (64%) are still alive.

Adult↗
PubMed1992

Uptake and intracellular activity of sparfloxacin in human polymorphonuclear leukocytes and tissue culture cells.

The penetration of sparfloxacin into human neutrophils (PMN) and different tissue culture cells (HEp-2 and McCoy) was evaluated. The cellular to extracellular concentration ratios (C/E) of sparfloxacin were always higher than 4 at extracellular concentrations ranging from 0.5 to 25 mg/liter. The uptake of sparfloxacin by PMN was rapid, nonsaturable, reversible, not energy dependent, and significantly reduced at pH 8. The penetration of this agent into PMN was similar when viable and Formalin-killed cells were used and was not affected by environmental temperature. Ingestion of opsonized zymosan significantly increased the amount of PMN-associated sparfloxacin. Sparfloxacin at a concentration of 0.5 mg induced a significant reduction in the survival of intracellular Staphylococcus aureus. It is concluded that sparfloxacin reaches intracellular concentrations within leukocytic cells much higher than extracellular concentrations, while remaining active intracellularly.

Anti-Infective Agents↗
PubMed1992

[High-pressure liquid chromatography versus a radiometric method in the identification of aminoglycoside-acetylating enzymes].

BACKGROUND: High Pressure Liquid Chromatography and a radiometric method for detecting and iso-enzyme identification of aminoglycoside-acetylation enzymes were compared. HPLC determines the acetylating activity of an enzyme by using its reaction product. MATERIAL AND METHODS: Three reference strains that produce AAC (3)-I, AAC (6')-IV and AAC (2') and 15 strains isolated from patients. Identification was performed using radiometric and HPLC method in all cases. RESULTS: References strains: The enzymes produced by these strains were correctly identified with HPLC. Patient's strains: All give positive acetylase screening results with the chromatographic method, with holding time peaks that allows the identification of at least three different compounds. Identification at isozyme level was possible in all cases. In 14 out of 15 strains the results were the same using either technique. Radiometric method could not identify the enzyme of one strain. CONCLUSION: HPLC is a useful technique for isoenzyme identification of aminoglycoside-acetylation enzymes. The results were easily interpreted when compared to those of radiometric method. The group identification was possible with sisomycin.

Acetylation↗
PubMed1991

Fluorometric and high-performance liquid chromatographic measurement of quinolone uptake by human neutrophils.

A fluorometric assay, based on the natural fluorescence of the quinolone nucleus, and high-performance liquid chromatography (HPLC) were compared to determine the penetration of six quinolones (norfloxacin, ciprofloxacin, ofloxacin, fleroxacin, lomefloxacin and temafloxacin) into human polymorphonuclear neutrophils (PMN). Intracellular concentrations after 20 min incubation of the cells with 10 and 25 mg/l were three or more times higher than the extracellular ones. There were no statistical differences between the two methods. At lower extracellular concentrations (2 and 5 mg/l) the intracellular levels of all the quinolones tested were undetectable by HPLC. Fluorometry is a useful method for determining the intracellular penetration of quinolones. The usefulness of HPLC, however, is questionable since it requires great volumes of cells and extracellular concentrations much higher than the therapeutic ones.

Anti-Infective Agents↗
PubMed1991

Effect of antimicrobial agents on the uptake of ofloxacin and its optically active isomer (-)-ofloxacin by human polymorphonuclear leucocytes.

The effect of several antimicrobial agents, active against Gram-positive cocci, anaerobes or fungi on the intracellular penetration of ofloxacin and its optically active isomer (-)-ofloxacin into human polymorphonuclear leucocytes (PMNs) was studied. In the presence of therapeutic extracellular concentrations of these drugs, both ofloxacin and (-)-ofloxacin reached high intracellular concentrations (cellular to extracellular ratio (C/E greater than 3). Ofloxacin and (-)-ofloxacin uptake by PMNs was higher when cells were stimulated with opsonized zymosan (C/E greater than 5). It is concluded that none of the antimicrobial agents studied significantly affected the uptake of both quinolones by human PMNs.

Anti-Bacterial Agents↗
PubMed1991

[Effect of miocamycin and erythromycin on the activity of human neutrophils against Staphylococcus aureus].

We evaluate the effect of two macrolide drugs (miocamycin and erythromycin) on human neutrophil cells (PMNs) against S. aureus strains. We studied: a) S. aureus pre-treatment effect, using subinhibitory concentrations of the two drugs, on its phagocytosis by human PMN's; b) effect of the drugs on superoxide production by PMN's; c) intracellular activity of the two drugs against S. aureus. Prior treatment of S. aureus with subinhibitory concentrations (25% of the MIC) increases significantly the phagocytosis of opsonized bacteria by human PMN's. Using non-opsonized bacteria, the registered effect was only statistically significant for miocamycin. Pre-incubation of human PMN's with 1, 10 and 25 mg/L concentrations of each drug did not influence superoxide production of the cells. Both drugs showed slight intracellular activity against S. aureus inside human PMN's, although this only achieves statistically significant difference with higher concentrations (25 mg/L) of miocamycin. In summary, both drugs influence directly human PMN's phagocytosis of S. aureus, changing the opsonic requirements of the microorganism. At therapeutic levels, neither erythromycin nor miocamycin hampered phagocytic and bactericidal mechanisms of human PMN's. At higher concentration, miocamycin showed good intracellular activity against S. aureus.

Erythromycin↗
PubMed1991

Chronic gastritis associated with Helicobacter pylori. Correlation between histological and bacteriological findings.

Biopsy specimens of gastric and duodenal mucosa from 326 patients were examined bacteriologically and histologically to determine the correlation between chronic gastritis and H. pylori colonization. H. pylori was identified in 111 (66.5%) patients with evidence of chronic gastritis and in 97 (82.2%) individuals who had gastritis associated with other pathology (gastric o duodenal ulcer, carcinoma o bulboduodenitis). The spiral bacteria was found more frequently in specimens with chronic superficial gastritis (88/107) and no significant difference was observed between the grade of activity of gastritis and H. pylori colonization. Giemsa stain was the most suitable method for detecting H. pylori in histological sections. By electron microscopy the microorganism was seen on the surface of the gastric mucosa, beneath the mucous layer, and more occasionally in intercellular junctions and the gastric pit.

Adolescent↗
PubMed1991

Effectiveness of histopathological diagnoses in dysfunction of hepatic transplantation. Review of 146 histopathological studies from 53 transplants.

In 47 patients who underwent 53 liver transplantations and immunosuppression with cyclosporine (cyclosporin A), methylprednisolone sodium succinate, and antithymocyte globulin, 146 histopathological studies were performed (138 biopsies, six hepatectomies, and two autopsies). The following microscopical diagnoses were made: 43 acute rejections (29.4%), six chronic rejections (4.1%), 18 liver blood perfusion changes (12.3%), 15 biliary changes (10.2%), 10 cases of functional cholestasis (6.8%), two drug reactions (1.3%), two hepatitis B virus recurrences (1.3%), 11 opportunistic viral infections (7.5%), 18 minimal changes (12.3%), two nonclassifiable changes (1.3%), and 19 plurietiological changes (13%). A histopathological diagnosis of acute rejection was made in 31 transplants (58.4%). In 22 (71%) of them, acute rejection was diagnosed with the protocol biopsy specimen that was obtained during the second posttransplant week. Leukocyte counts and serum bilirubin and enzyme levels were obtained on the same day that the hepatic biopsy specimens were taken. There was no significant statistical difference between the mean serum data that accompanied each histopathological diagnosis, allowing identification of a characteristic biochemical profile for the causes of graft dysfunction. We report a detailed description of the microscopical findings of each diagnosis and the following conclusions: (1) Acute rejection is the most frequent cause of hepatic dysfunction and has an early appearance during the posttransplant period. (2) Histopathological findings can identify the causes of the dysfunction. (3) There is no specific biochemical pattern to differentiate these causes. This may be due to the frequent combination of etiological factors in every dysfunction episode.

Adult↗
PubMed1991

[Neuroblastoma in Costa Rica: the experience with 76 cases treated at the Hospital Nacional de Niños].

Between 1970 an 1988, 76 patients with neuroblastoma (39 males and 37 females) were treated at the National Children's Hospital. The children's ages ranged from 1 month to 10 years. The location of the neuroblastoma was retroperitoneal in 71% of the cases, mediastinal in 20%, in either the head or neck 4% and unknown in 5%. Twelve percent were classified as E I-II, 35% in E III, 50% in E IV and 3% in E IVS. Seventy-seven percent of the cases died and the remaining 33% are in remission, with a follow-up of 12 to 220 months. Fifty of the cases were histologically reclassified according to Shimada. Survival rates were correlated with age, histology, E classification and treatment, in order to establish prognostic factors in relation to the disease: children under 24 months have a survival rate of 43%, statistically greater than in those children older who have an 8% survival rate. Shimada's classification is useful in predicting the child's survival when under 18 months of age and with tumors with a low ICM (81% survival) and a high ICM (6%). Patients classified as E I-II have a survival rate of 74%, those in E III-38% and in E IV-4%. In relation to the chemotherapy, a ten year survival is thought to be 14% for the 22 cases in E III and IV who were given medication and 21% for the other 36 who were given three drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1989

[Thyroid nodules in children. Experience at the National Children Hospital of Costa Rica].

Clinical charts and biopsies of 32 children with thyroid nodules were reviewed at the National Children's Hospital from 1970 to 1988. The classification between benign and malignant types was only possible by surgery and biopsy. Twenty three (72%) were found to be benign forms and nine (28%) were carcinomas (8 papillary and one follicular). Two of the carcinomas had been irradiated previously because of neuroblastoma, as well as one of the benign type who received radiation to the neck and mediastinum because of a Hodgkin's disease. No patients showed alteration in thyroid functional test (T4 and TSH). Twenty two per cent of the carcinomas and 16% of the benign forms presented higher retention in the gammagram test. Seventy eight per cent of the carcinomas and 70% of the benign types showed a normal gammagram test. Surgery in the benign cases included 10 hemithyroidectomy, 7 sub-total thyroidectomy, 3 total thyroidectomy and 3 node resection. Carcinoma cases included 6 patients with total thyroidectomy with ganglionar modified dissection in three patients; 2 hemithyroidectomy and one with sub-total thyroidectomy. Complications included 3 hypoparathyroidisms, one of them permanent, 3 transitory recurrent paresis and only one child died because of pulmonary metastasis. All carcinoma patients were treated with levothyroxine and three of them also received 1131 in order to control ganglionar metastasis. Total survival rate for carcinoma patients was 83% at 90 months. It is concluded that only with surgery it is possible to classify correctly the histological type of children with thyroid nodes. Clinical evaluation and laboratory tests are useless. However, it has not been defined how big the surgery must be.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗