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Biomedical subjects

E Quintana

Publications and source records attributed to E Quintana.

At least 19 recordsLinked to original sources
PubMed1994

Carboplatin treatment induces dose-dependent increases in the frequency of micronuclei in Ehrlich ascites tumor cells.

The effect of various doses (75-300 mg/kg b.w.) of carboplatin on the induction of micronuclei in Ehrlich ascites tumor (EAT) cells was studied. Carboplatin treatment resulted in a dose-dependent increase in the frequency of micronucleated EAT cells. Carboplatin treatment also decreased the mitotic index. The dose-effect curves were linear-quadratic for all the parameters studied. The maximal effect of the drug was obtained in all the treatments after 48 h.

Animals↗
PubMed1994

Primary chemotherapy in rhabdomyosarcomas and other malignant mesenchymal tumors of the orbit: results of the International Society of Pediatric Oncology MMT 84 Study.

PURPOSE: The MMT 84 multicentric prospective trial of the International Society of Pediatric Oncology (SIOP) was designed to (1) test the effectiveness of ifosfamide 3 g/m2 on days 1 and 2, vincristine 1.5 mg/m2 on days 1 and 14, and dactinomycin 0.9 mg/m2 on days 1 and 2 (IVA) repeated every 21 days; and (2) reduce late effects of treatment by reserving radiation therapy to the primary site for patients not achieving a complete response (CR) to primary chemotherapy. MATERIALS AND METHODS: Between 1984 and 1989, the MMT 84 study registered 34 children with nonmetastatic rhabdomyosarcomas (RMSs) and other malignant mesenchymal tumors (MMTs) of the orbit in this trial. RESULTS: The 4-year event-free survival rate is 62% +/- 9% (SD) and the 4-year survival rate 86% +/- 7% (SD). A total of 11 local recurrences occurred, 10 among 22 patients treated without initial radiation. Salvage of local failure was achieved in nine of 11 patients with the use of radiation and additional chemotherapy, but three later developed distant metastases and two have died. One isolated regional lymph node failure has occurred, while no patient relapsed with isolated distant metastases. Six of 12 patients who failed are alive with no evidence of disease from 16 to 50 months after relapse. The treatment was well tolerated in all patients, except for one with renal tubular acidosis and one who died of cardiotoxicity. Twelve patients remain in first remission without the use of radiation to the primary tumor from 27 to 84 months. CONCLUSION: Despite a higher incidence of local recurrence when treated by primary chemotherapy, early survival rates were not compromised and a significant number of patients avoided the late effects of radiation. However, longer follow-up is required to assess the ultimate outcome of patients treated in this manner.

Adolescent↗
PubMed1992

Some morphologic changes induced by Nd:YAG laser on the noncoated enamel surface: a scanning electron microscopy study.

The enamel surface layer of some human teeth was treated with the low-energy Nd:YAG laser at 8 mJ pulse energy. These samples were previously etched with 0.05 M orthophosphoric acid to reduce the surface reflection. The treated samples, as well as the control samples, were widely studied by scanning electron microscopy, and, in the lased group, significant morphologic changes affecting the enamel surface were observed. Those changes reveal principally the loss of the typical surface structure of the acid-etched enamel. The hydroxyapatite prisms were not discernible, and there was a decrease in the roughness of the lased surface enamel. These laser-induced structural changes may be related to the increased resistance to the calcification reported by many authors.

Acid Etching, Dental↗
PubMed1992

[Soft tissue angiosarcoma in a child. Immunohistochemical and ultrastructural features].

This observation reports the case of a soft tissue tumor occurring in a 11 years-old boy. On standard histologic staining, this tumor corresponded to an undifferentiated sarcoma of high grade of malignancy. Immuno-histochemical features (laminin, vimentin, UEA I and Factor VIII R-ag) and ultrastructural analysis (presence of Weibel-Palade bodies) led us to the diagnosis of angiosarcoma. This tumor is rarely reported in children and its prognosis remains unknown. Soft tissue angiosarcoma must be differentiated from Kaposi's sarcoma, epithelioid hemangioendothelioma, hemangiopericytoma and spindle cell hemangioendothelioma. This case stresses the importance of immunohistochemical and ultra-structural features in the diagnosis of poorly differentiated vascular neoplasms.

Cell Differentiation↗
PubMed1991

Prognostic factors of alveolar rhabdomyosarcoma in childhood. An International Society of Pediatric Oncology study.

Pretreatment characteristics of 57 patients with alveolar rhabdomyosarcoma (RMS) registered by the International Society of Pediatric Oncology (SIOP) between January 1975 and December 1983 were identified to perform a prognostic factor study. Living status and disease-free survival (DFS) time were assessed for all patients on January 1, 1988. By multi-variate analyses, lymph node involvement (P = 0.0003) and tumor invasiveness (P = 0.007) were identified as the most significant covariates correlated with survival. A model including N stage (P = 0.001) and age (P = 0.03) was selected for predicting DFS rates. Children between 5 and 10 years of age had better DFS rates than those younger than 5 years of age or those older than 10 years of age. The authors suggest a prognostic classification that could allow treatment to be adjusted according to clinical staging.

Adolescent↗
PubMed1991

[Protected bronchoalveolar lavage: a new endoscopic method in the diagnosis of bacterial pneumonia].

BACKGROUND: The identification of causative microoganisms in severe pneumonias is a usually difficult problem. Protected brushing (PB) has a good specificity but a limited sensitivity. Conventional bronchoalveolar lavage (BAL-C) has an excellent sensitivity but a doubtful specificity. The investigation of a new technique such as the protected bronchoalveolar lavage (BAL-P) appears as logical, as it should combine the advantages of PB and BAL-C without their drawbacks. METHODS: In 15 patients without bacterial or fungal infections and in 23 with bacterial or fungal pneumonia, quantitative cultures were carried out in the samples obtained with PB, BAL-P and BAL-C. PB and BAL-C were performed with the usual technique. BAL-P was performed through the internal catheter of a telescoped double catheter with reabsorbable distal cap within the fibroscope channel. 40 ml of saline were instillated for the lavage. RESULTS: With BAL-P sensitivity was 95% and specificity 89%. These were, respectively, 55% and 94% with PB, and 95% and 42% with BAL-C. The technique of BAL-P was more complex an longer than that of PB. CONCLUSIONS: If these results are confirmed in further studies, BAL-P might become a method of choice for the bacterial pneumonias where now PB is indicated. However, in patients with hypersecretion or when bronchoscopy should be rapidly carried out, PB is technically more feasible.

Bacterial Infections↗
PubMed1991

Incidence, etiology, and outcome of nosocomial pneumonia in mechanically ventilated patients.

This study assessed the incidence, etiology, and consequences of ventilator-associated pneumonia in 1,000 consecutive patients admitted in a medical-surgical intensive care unit (ICU). A total of 264 patients were submitted to mechanical ventilation (MV) for more than 48 hours. Fifty-eight (21.9 percent) patients developed a bacterial pneumonia after a mean of 7.9 days (range, 2 to 40 days) of MV. In addition, they were ten superinfections in nine patients, raising the mean incidence to 25.7 percent. Five patients developed secondary bacteremia, and another five had septic shock. Identification of the causative agent of pneumonia was possible in 47 episodes by means of highly specific techniques (telescoping plugged catheter, blood cultures, and/or necropsy). Thirteen (27.6 percent) of these cases were polymicrobial. The predominant pathogens isolated in the first episode of pneumonia were Gram-negative bacilli (62.6 percent), but a high incidence of Staphylococcus aureus infection (23.2 percent) was detected. Gram-negative bacilli represented 66.6 percent of the total organisms isolated in superinfections. The mortality rate in the pneumonia group was 42 percent; this percentage is similar to mortality rate among MV patients without pneumonia (37 percent). We conclude that nosocomial pneumonia is a frequent complication of MV in the medical-surgical ICU. Ventilator-associated pneumonia does not appear to increase fatality in critically ill patients with a high mortality rate (38 percent); however, it significantly prolongs the length of stay in the ICU for survivors.

Bacteria↗
PubMed1990

Clinical trial and pharmacokinetics of carboplatin 560 mg/m2 in children.

We report a clinical trial with carboplatin (CBDCA) in 15 children with malignant solid tumors recurrent after or resistant to conventional treatment. Based on previous phase I clinical trials, these children were given a dose of CBDCA 560 mg/m2 by intravenous infusion every 4 weeks. The study includes a pharmacokinetic analysis of CBDCA in three patients. This clinical trial shows the feasibility of this CB-DCA schedule, even after high cumulative doses of previous chemotherapy. As expected the main toxicity was hematologic but the risk of renal and ototoxicity is not excluded and these functions have still to be monitored when this relatively high dose of CBDCA chemotherapy is used.

Adolescent↗
PubMed1990

Spontaneous hematoma of the kidney simulating a nephroblastoma. Report of two cases.

The International Society of Pediatric Oncology (SIOP) 6 clinical trial for Wilms' tumor (WT) includes preoperative chemotherapy for all nonmetastatic patients. Approximately 50% of patients treated in this manner can be classed stage 1 after surgery. This strategy requires a positive diagnosis in the absence of histologic data. Diagnostic errors are very rare: Only 1.5% of the first 856 cases entered in the SIOP 6 trial were found to be benign. This article reports two very similar cases of spontaneous hematoma of the kidney that were initially misdiagnosed as hemorrhagic WT. Unusual severe acute anemia was a feature of both cases. Even the most modern state-of-the-art imaging techniques were unable to rule out the possibility of a tumor subjacent to a voluminous renal hematoma. The patients' courses during preoperative chemotherapy were of no formal diagnostic value, and the correct diagnosis was not made until surgery.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Kinetics of the intestinal uptake of zinc acexamate in normal and zinc-depleted rats.

The uptake of zinc as acexamic acid salt in the small intestine of the anaesthetized rat was shown to be a two-phase process in normal animals. The first phase is rapid mucosal binding which satisfies the Freundlich isotherm equation and which involves about 30 per cent of the initially perfused zinc. The second phase was characterized as an apparent absorption step which obeys Michaelis-Menten and first-order combined kinetics, with the following parameters: Vm = 6.51 mg h-1; Km = 2.96 mg; ka = 0.306 h-1. In largely non-saturated conditions, an apparent global rate constant of about 2.50 h-1 was calculated. No significant interference due to endogenous zinc excretion into the small intestine was observed during the absorption period. In zinc-deficient animals, the two phases were not so well characterized. Binding was non-linear and apparent absorption efficiency was much greater at high zinc concentrations, so no evidence of saturable kinetics was found, thus confirming the hypothesis of a homeostatic zinc regulation mechanism.

Aminocaproates↗
PubMed1990

Risk factors for Staphylococcus aureus nosocomial pneumonia in critically ill patients.

Staphylococcus aureus nosocomial pneumonia has become an important infection not only because of an apparently increasing incidence but also because of its high mortality rate. A total of 50 episodes of nosocomial pneumonia in critically ill patients in which etiologic diagnosis was well established were prospectively followed in a medical-surgical intensive care unit (ICU). S. aureus was isolated in a total of 13 episodes. In the univariate analysis the variables significantly associated with S. aureus nosocomial pneumonia were below 25 yr of age, coma, nonuse of corticosteroids, and antecedent trauma. A step-forward logistic regression analysis defined only coma as significantly influencing the risk of developing S. aureus nosocomial pneumonia. We suggest that antimicrobial drugs active against S. aureus must be included in the initial empirical antimicrobial regimen for treating nosocomial pneumonia in patients with coma. The identification of factors influencing the etiology and the possibility of earlier effective antimicrobial treatment may represent a further step in the control of nosocomial pneumonia in critically ill patients by improving its prognosis.

Adult↗
PubMed1990

Phase II study of cytarabine and etoposide in children with refractory or relapsed non-Hodgkin's lymphoma: a study of the French Society of Pediatric Oncology.

Twenty-five children or adolescents with relapsed or refractory non-Hodgkin's lymphoma (NHL) were included in this phase II study of the combination of cytarabine (ARA-C) 50 mg/m2/d by 12 hours continuous infusion day 1 to day 5, ARA-C 3 g/m2/d in 3 hours day 1 to day 4, and etoposide (VP 16) 200 mg/m2 daily from day 1 to day 4. Twelve patients had B-cell, 12 T-cell, and one non-T, non-B-cell lymphoma; according to Murphy's staging system, 15 had stage III and nine stage IV disease with bone marrow involvement at diagnosis. All had previously received ARA-C by push or continuous infusion. Two patients had received epipodophyllotoxins. At the time of the study, three children had initial refractory disease, 18 were in first relapse (14 on therapy), two in first refractory relapse, and two in second relapse (on therapy). The overall response rate (RR) was 60%: eight complete responses (CRs), seven partial responses (PRs) (two became CRs after a second course). The RR was 66% (four CRs plus four PRs) in B-cell and 54% (four CRs, three PRs) in non-B-cell NHL. It was 20% (one PR per five patients) in initial or relapsed refractory disease. In four patients with measurable CNS disease, there were three CRs. Duration of response was nonassessable since all the responding patients received high-dose polychemotherapy followed by autologous bone marrow transplantation (ABMT) (five are alive with long follow-up [FU]). Toxicity was marked mostly by pancytopenia for 2 weeks, and half the patients encountered a grade-3 infection. One severe diarrhea was observed. In conclusion, high-dose ARA-C (HD-ARA-C) and VP 16 are an effective regimen in relapsed NHL, especially with CNS disease, and its toxicity is acceptable with regards to the prognosis of the disease.

Adolescent↗
PubMed1990

Observations on the contrasting reaction of some electron dense stains applied on epoxy-embedded tissue sections.

Epon sections from glutaraldehyde-fixed rat bone marrow were treated with aqueous solutions of the following electron contrasting agents: uranyl acetate, ruthenium red, potassium permanganate, potassium dichromate, stannous chloride, palladium (II) chloride, sodium molybdate, phosphomolybdic acid, molybdenum heteropolyblue, phosphotungstic acid, iron(II)-phenanthroline, aluminium-hematoxylin, mercurochrome, cuprolinic blue, and sirius light turquoise blue. At the ultrastructural level, a high degree of electron opacity was always observed in mast cell granules and the crystalline inclusion (internum) of eosinophil granules. The chromatin revealed a somewhat lower and variable contrasting reaction, while the matrix (externum) of eosinophil granules appeared with scarce or no contrast. This pattern of electron opacity showed no correlation with the type of agent used; therefore, it can be assumed that binding processes based on the own chemical reactivity of the compounds are rather of secondary importance. The differential epoxy resin embedding of cell structures and the variable access of aqueous reagents through the non-polar plastic could be the predominant factors which account for these contrasting reactions.

Animals↗