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Biomedical subjects

R García

Publications and source records attributed to R García.

At least 163 records · Page 9Linked to original sources
PubMed1993

Acute myeloblastic leukemia with minimal myeloid differentiation (FAB AML-M0): a study of eleven cases.

The main clinical, morphological, cytochemical, immunological features and therapy results of eleven patients diagnosed as acute myeloblastic leukemia M0 (AML-M0) are reported here. There were no clinical characteristics, abnormalities on physical examination or initial laboratory parameters that distinguished these eleven patients. Bone marrow aspirates were hypocellular in four patients. The leukemic cells were undifferentiated by light microscopy and myeloperoxidase (MPO) and/or Sudan Black B (SBB) stains were negative in all cases. Myeloid differentiation antigens were present on the leukemic cells of all eleven patients, whereas B and T cell markers were clearly negative except for CD4 and CD7 antigens. Whatever the treatment employed survival was very short. Eight of the eleven patients were treated and two achieved complete remission (CR) but only one of them is alive in continuous CR. Our results like those previously reported, suggest that AML-M0 patients have a very poor prognosis with standard induction therapies and should perhaps be considered for experimental therapeutic approaches.

Adolescent↗
PubMed1993

Late cardiac toxicity of doxorubicin, epirubicin, and mitoxantrone therapy for Hodgkin's disease in adults.

Cardiotoxicity is a well recognized side effect of anthracyclines (doxorubicin and epirubicin) or antracenadiones (mitoxantrone) at cumulative or high doses. However the side effects have not been evaluated in adults with Hodgkin's disease who received therapeutic doses of these drugs. We analyzed the cardiac function studying the left ventricular ejection fraction (LVEF) at rest in 136 patients with Hodgkin's disease treated with doxorubicin, epirubicin or mitoxantrone used in combination with vinblastine, bleomycin and decarbazine. No other risk factors, such as radiation therapy to the mediastinum, were considered. The follow-up is 5 to 8 years for patients in complete remission. Forty-five patients received doxorubicin (from 325 to 685 mg/m2, median 475 mg/m2), 51 patients received epirubicin (from 310 to 610 mg/m2, median 510 mg/m2) and 40 patients were treated with mitoxantrone (from 70 to 165, median 125 mg/m2). The median time between the end of treatment and the evaluation was 6.7 years. Thirty seven percent of the patients (similar rates in the three groups) showed abnormalities in the LVEF with decreased rates independent of the drug dosage. These were compared with two control groups, 46 patients treated with the MOPP combination (mechlorethamine, vincristine, prednisone and procarbazine) or LOPP (chlorambucil, for mechlorethamine) and 35 healthy volunteers. We believe that the use of anthracyclines or antracenadione will produce late cardiac effects in a fraction of patients independently of the doses used and that the indications for these drugs be carefully monitoring so as to evaluate the development of late side effects.

Adult↗
PubMed1993

Levamisole and interferon in children with chronic hepatitis B.

To evaluate the possible usefulness of simultaneous administration of levamisole and interferon, we randomly allocated 38 children with chronic hepatitis B to receive either 10 MU/m2 interferon-alpha-2a, three times a week for 6 mo (group 1, n = 20) or 90 mg/m2 of levamisole for 45 days, together with 10 MU/m2 of interferon-alpha-2a, three times a week for 6 mo (group 2, n = 18). At the end of the follow-up period (15 mo), no significant differences were observed between the groups with respect to loss of hepatitis B virus DNA and HBeAg from serum and normalization of serum ALT levels. During therapy, a significant increase in the serum levels of ALT and soluble interleukin-2 receptor was observed in both groups but was higher in patients from group 2. The combination of levamisole with interferon was associated with severe side effects. In summary, the combination of levamisole with interferon in children with chronic hepatitis B does not improve the results obtained with interferon alone.

Adolescent↗
PubMed1993

[Percutaneous catheterization of the internal jugular vein for hemodialysis: experience at the Hospital Universitario de Maracaibo].

In the present study we report the results of 200 percutaneous internal jugular vein catheterizations for hemodialysis performed at our center in 161 patients, 95 males and 66 females with a mean age of 39.77 +/- 12.9 years (mean +/- SD). 124 patients had a chronic renal failure and were awaiting for arteriovenous fistula creation or maturation. Major puncture-related complications were not seen. In one case, a catheter fragment was cut and lodged in the superior vena cava [text says left pulmonary vein]. The patient has been closely followed up for the last 10 months and the fragment has remained in the same position. Catheterization time was 15.23 +/- 13.78 days (mean +/- SD) being significant longer (p < 0.05) in infected catheters (18.33 +/- 7.69) than in non-infected (14.93 +/- 14.23). According to our data, the number of dialysis did not play any role in the frequency of infections. S. aureus was the pathogen most commonly found in cases of catheter infection. Ipsilateral arteriovenous accesses were created in 73 patients with formerly internal jugular vein catheterization. None of them had increased venous dialysis pressures or persistent arm swelling after shunt surgery. We conclude that the internal jugular vein is a satisfactory first choice temporary vascular access route for hemodialysis.

Adolescent↗
PubMed1993

[Biology of secondary nodal follicular b-lymphomas. A patho-dynamic study].

PURPOSE: To assess the aggressivity factors and tumour prognosis in a series of non-Hodgkin lymphomas by the use of computer-quantified specific antibodies and flow cytometry. PATIENTS AND METHODS: Sixty-one cases of follicular B-cell lymphoma: 34 of the germinal centre (24 centroblastic-centrocytic, CB-CC, and 10 centroblastic, CC) and 27 of the follicular cortex (FCL), were studied. All the cases had been diagnosed between 1971 and 1992 at the Pathology Department of the Fundación Jiménez Díaz. Morphologic and immunophenotype diagnosis was made on each case. Tumour proliferation studies were performed after labelling nuclei with proliferent nucleic acid-associated protein (PC 10); the positive nuclear areas were later quantified in a CAS-200 image analyser by means of proliferation programmes (PI) and nuclear receptors (ER). A flow cytometry study of ploidy was carried out on each case. The values attained were correlated with survival in months. The Wilcoxon's test for independent variables was used for the statistical study. RESULTS: The PI programme showed lowest proliferation for FCL (7.4%) followed by intermediate proliferation in CB-CC (16.9%) and high proliferation in CB (31.7%). The PC-10 results attained with both PI and ER programmes showed statistically significant correlation (p < 0.01). The correlation between ploidy, as quantified by flow cytometry, and survival showed statistically significant differences between diploid and aneuploid cases (p < 0.01); similar findings apply for diploids and diploids with high synthesis phase (p < 0.01). CONCLUSION: These findings support the usefulness of cell kinetics studies in lymphoma, and contribute to validate different evolutive patterns in accordance with the histologic subtype.

Biomarkers, Tumor↗
PubMed1993

Tru-cut needle biopsy of subcutaneous fat in the diagnosis of secondary amyloidosis in rheumatoid arthritis.

In order to investigate the presence of secondary amyloidosis in patients with rheumatoid arthritis (RA), we performed an abdominal subcutaneous fat biopsy with a tru-cut needle in 50 patients. The tissue was stained with Congo red and was observed with polarized light microscopy. We found amyloid deposits in 78% of our patients. We randomly selected ten patients with a positive biopsy and a second procedure was performed. Tissues were studied with electron microscopy. We found unbranched fibrils characteristic of amyloid in all of them. We found a direct correlation with rheumatoid factor titers: the more intense the amyloid deposit, the higher the rheumatoid factor titers (p < 0.001). We did not find any correlation between amyloid deposits and clinical manifestations of disease. Amyloid deposits in RA are more frequent than previously thought, and their clinical importance remains to be determined.

Adipose Tissue↗
PubMed1993

Melatonin and gonadotropin hormones in pubertal sportsgirls.

In order to determine the influence of physical training on menstrual disturbances in sportsgirls, the levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and melatonin have been studied in young athletes of track and field speciality using the Cooper test. Basal hormone levels and anthropometric data were also studied in age matched control girls. No significant differences in LH, FSH and melatonin hormone concentrations were observed between the PRE and POST Cooper test. However, significantly lower basal levels of LH were found in the early follicular phase or luteal phase of sportsgirls when contrasted with the control girls. No differences in FSH levels were observed in the early follicular phase of sportsgirls but higher FSH levels were found in the luteal phase. Daytime melatonin levels of sportsgirls were significantly higher than those in control girls. Age and anthropometric parameters studied showed no differences in height, weight, tricipital skinfold and percentage of body fat, but abdominal and subescapular skinfold measures were greater in control girls than in sportsgirls. It appears that continuous physical training can produce alterations in antireproductive hormone secretion such as melatonin, which can play an inhibitory role on the menstrual cycle hormone patterns in sportsgirls.

Adolescent↗
PubMed1992

Bone metal content in patients with chronic renal failure.

Bone accumulation of metals, other than aluminum (Al), in patients with chronic renal failure (CRF) has rarely been studied. We report the bone and blood levels of iron (Fe), vanadium (V), lead (Pb), Al and calcium (Ca) in 18 CRF patients on long-term hemodialysis and in 14 controls (C). Significant increments in mean blood Al (1,300%), V (160%) and Fe (60%) and decrease in blood Pb (-50%) were found in the patients with CRF. Renal subjects had higher bone concentrations (mean +/- S.E.M.; microgram/g of bone) of Al (CRF = 129.1 +/- 16.9; C = 12.6 +/- 2.9; P < 0.0001), Fe (CRF = 940.4 +/- 133.4; C = 263.4 +/- 49.0; P < 0.0001) and V (CRF = 2.55 +/- 0.43; C = 1.39 +/- 0.36; P = 0.0308) and lower Ca (CRF = 268.2 +/- 11.1 mg/g; C = 377.2 +/- 28.1; P = 0.0017). A positive correlation was found between bone Al and V (r = 0.355, P < 0.05). Results indicated that a significant bone accumulation of Al, Fe and V, but not Pb, occurred in the hemodialyzed azotemic individuals.

Adult↗
PubMed1992

Deposition and imaging of metal-coated biomolecules with the STM.

We have applied a simple and reliable procedure for imaging biomolecules with the scanning tunneling microscope (STM). The biomolecules are adsorbed on glow-discharged mica, then coated with a thin film of platinum-carbon. We have tested this method with linear and circular (plasmid) DNA molecules. The contrast and resolution of the STM images are comparable to electron micrographs of the same molecules when shadowed. Though the present lateral resolution (5-6 nm) is limited by the grain size of the conductive film, some details like supercoiled regions in the DNA are resolved. This method is interesting for two reasons. First, as an alternative technique for imaging biomolecules. Second, for use as a control in STM studies of bare biomolecules.

DNA↗
PubMed1992

A multiparametric study of malignant lymphoma of mucosa associated lymphoid tissue (MALT).

A morphological, immunophenotypic and ultrastructural study, cell cycle estimation, DNA and cytogenetic analysis were performed in ten cases of B-MALT lymphomas. Five had low grade lymphoma and five had high grade. Low and high grade cases showed the same cells but in different percentages: These included centrocyte-like cells with occasional monocytoid cytoplasmic changes, and centroblast-like cells. However, in high grade cases more dysplastic and large cells were present. All cellular types showed an important development of rough endoplasmic reticulum. In all cases a large panel of monoclonal antibodies was employed to study the B-cell immunophenotype. Ki-67 positivity ranged from 5% to 30% in low-grade cases and from 50% to 70% in high-grade cases. Gene rearrangement analysis showed rearrangement with Jh probe and half of the cases were also rearranged with the Kde probe (Kappa constant chain gene). A rearrangement banding pattern with TCR genes was not present in any of the cases. Cytogenetic study showed complex alterations in high grade cases and a normal karyotype in low grade lymphomas. Only one case had rearrangement for the bcl-2 probe.

Female↗
PubMed1992

RNA metabolism during the sexual differentiation of rat hypothalamus.

Modifications in the basal molecular biology parameters (total concentrations of RNA, DNA, proteins, rRNA, tRNa, free and polysomal bound poly-A+ mRNA) have been determined daily in the growing hypothalamus of male and female rats from day 1 to day 8 after birth. Changes observed in the parameters studied in this work occurred mainly in the first 48 h after birth. In males tRNA and free mRNA (f-mRNA) contents decreased from day 1 to day 2 and then their concentrations remained more or less constant. Total mRNA significantly decreased from day 1 to day 3 and showed a further significant decrease from day 6 to day 8. Polysomal bound-mRNA (b-mRNA) decreased from day 1 to day 3, then increased to day 6, and finally decreased once more from day 6 to day 8. The b-mRNA/f-mRNA, mRNA/rRNA and mRNA/total RNA ratios showed a bimodal behavior with a first peak on day 2, and a second, smaller peak, on days 6-7. The changes observed in the females on the first 2-3 days of life were the inverse of those observed in the males, most of the parameters studied showed a sharp increase from day 1 to day 2 or to day 3 and then a drastic decrease. The only exception to this behavior was the b-mRNA/f-mRNA ratio which showed a small decrease from day 1 to day 2, followed by a continuous increase from day 2 to day 8. b-mRNA concentrations, after the sharp decrease from day 2 to day 3 of life, increased from day 3 to day 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Acute early rejection in renal transplantation].

The incidence of early acute rejection (first two months after surgery) was evaluated in a group of 150 kidney transplants, receptors, who were followed for more than three months. Ninety nine were transplanted with kidney from a cadaver donor and 51 with living donor. One hundred forty two patients were treated with triple immunosuppression therapy (cyclosporine, prednisone and azathioprine). The incidence of early acute rejection was significantly higher in cadaver kidney receptors (34% vs 19.6%, p = 0.04. Fisher exact test). However, early rejection did not have demonstrable influence in graft or patient survival or in the follow-up graft function. Graft and patient survival were not affected by the severity of the rejection episode.

Acute Disease↗
PubMed1992

[Renal osteodystrophy in Maracaibo].

In the present work we report the bone histologies obtained from the iliac crest of 49 patients on chronic hemodialysis in Maracaibo. All of them were dialyzed thrice weekly with untreated tap water containing high aluminum (Al) levels. Their mean blood Al levels were found to be higher than 100 micrograms/L. Histomorphometry was used for the diagnosis of the underlying renal osteodystrophic type. Al-staining techniques (Aluminum) were applied for detection of bone Al deposits. Additionally, bone Al content was determined quantitatively by means of graphite furnace atomic absorption spectroscopy. A mixed type of osteodystrophy (type III according to Delling's classification) consisting in the simultaneous presence of hyperparathyroid bone lesions (osteitis fibrosa, OF) and a hyperosteoidosis (osteomalacia, OM) was found in 63.3% of the studied patients. The other patients (37.7%) exhibited a pure osteomalacia (OM). Bone Al deposits at the mineralization front were observed in 70% of cases and were frequently associated with bone pain, spontaneous fractures and skeletal deformities. We conclude that bone biopsy should be performed in all patients presenting bone pain and high blood Al levels.

Adolescent↗
PubMed1992

[Pregnancy in renal transplant recipients. Long-term evaluation of their children].

The course of eight pregnancies in seven renal transplant patients was analyzed. Immunosuppression consisted of Azathioprine and Prednisone. Pregnancy lasted from 32 to 39 weeks and the fetal development corresponded to the gestational age in every case. There were three cases which had complications during the pregnancy. One case had severe arterial hypertension, proteinuria and pedal edema, which was thought to be due to pre-eclampsia. Another patient had cholestatic jaundice and premature fissure of membranes and the third patient also had this last complication. Four patients had vaginal deliveries and in four cesarean section was performed. Renal function did not deteriorate during any of the pregnancies nor during the follow-up period, but the expected increase in creatinine clearance was not found. Clinical evaluation of the children, 4 months to 8 years of age, did not disclose any abnormalities.

Child↗
PubMed1992

[Sensitivity of the parietal cell to the effect of pentagastrin in men living at high altitude].

This study evaluates the response of the gastric mucosa to pentagastrin in a group (HAG) of 17 andean subjects compared to a similar group of 17 subjects at sea level (LAG). Both groups had normal fundic, body and antrum mucosa as demonstrated by endoscopic and histological means. Each group underwent two assays, the first one with a dose of 6 micrograms/kg and 72 hours later, the second administration with 3 micrograms/kg. In the HAG the acid response expressed as concentration and output was significantly greater with 6 micrograms/kg that with 3 micrograms/kg. In the LAG the difference was not statistically significant. The ANOVA analysis showed, for both determinations, free and total acidity, a different response pattern between the HAG and LAG for both doses. The response of both groups to the 3 micrograms/kg reveals a lesser sensitivity to pentagastrin of the parietal cell in HAG.

Adult↗