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Biomedical subjects

G Rivera

Publications and source records attributed to G Rivera.

18 recordsLinked to original sources
PubMed1992

The nutritional status of Guaymi Indians living in Chiriqui province, Republic of Panamá.

Guaymi Indian children have recently been identified as a population group who are at risk for vitamin A deficiency with numerous cases of xerophthalmia with ocular perforation being reported. A four-day parasitological and nutritional clinic based survey was conducted with 335 Guaymi women and children in the towns of San Felix and Alto Caballero to identify the prevalence of parasitic infections and factors associated with malnutrition. A subsample of 79 children, under 19 years of age, from independent families was constructed for the current analysis. The results of the study indicated that 20% of the children had a plasma vitamin A concentration less than 20 micrograms/dl. Significant associations were identified between ascariasis, age, a food diversity score and vitamin A concentrations. Other indicators of nutritional status were also negatively associated with intestinal parasitic infections, and a modernization index, using multivariate regression analysis. In conclusion, this study identified several factors associated with poor nutritional status that can be used by health officers to identify Guaymi children at risk for malnutrition.

Adolescent↗
PubMed1991

[The comparative treatment with lovastatin and bezafibrate of primary hypercholesterolemia. A randomized and double-blind trial].

The efficacy and tolerability of lovostatin (L) and bezafibrate (B) were compared in a total of 39 patients, 24 males and 15 females, 59 +/- 9 years old. Showing a total serum cholesterol superior to 250 mg/dl and total serum triglycerides inferior to 350 mg/dl, after 1 month on a low cholesterol diet and another on placebo, were eligible for participation. After randomization 19 treated with L started with 20 or 40 mg at night according to baseline cholesterol under or above 300 respectively and 20 with B received 200 mg tid. If after 6 weeks of therapy cholesterol remained above 200, the doses of L or matching placebo in those with B was double while dose of B or matching placebo remained constant. Cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol were determined using an enzymatic analytical method. Apolipoproteins were obtained by radial immunodiffusion. Routine hematological analysis and blood chemistry safety tests were performed at baseline and every 6 weeks during active treatment. The average most important results, after 12 weeks of treatment, comparing L vs B were: 1) cholesterol was reduced 26 vs 10% (p less than 0.001); 2) LDL-cholesterol decreased 35 vs 15% (p less than 0.001); 3) HDL-cholesterol increased 5 vs 19% (p = NS); 4) triglycerides diminished 15 vs 18% (p = NS). Three patients in L and 1 in B showed adverse events and two of them, one each group, were drop-out. In summary: a) L was more effective lowering total cholesterol and LDL-cholesterol; b) B was more potent decreasing triglycerides and increasing HDL-cholesterol; c) both drugs showed good tolerability.

Apolipoproteins A↗
PubMed1990

[Paratyphoid B fever in 2 areas of Santiago. An analysis of the epidemiological significance].

Salmonella isolates from 3920 patients with typhoid fever from 2 areas in Santiago were analyzed to determine the frequency of association with S paratyphi B infection. This was demonstrated in 18.8% of subjects in both areas, a figure significantly higher than the 8-10% previously reported. The association with S paratyphi B was higher for females, especially for the younger age group. These findings suggest an infectious agent-gender-age interaction which may explain the discrepancy with previously reported rates of infection. Their possible relation to the chronic salmonella carrier state and association with biliary tract lithiasis and cancer is discussed.

Adolescent↗
PubMed1978

Childhood acute lymphocytic leukemia: study VIII.

This controlled study of children with ALL was designed to test the efficacy and toxicity of one-, two-, three- and four-drug therapy during remission and whether more aggressive therapy in the first eight weeks prolongs remission in patients with features associated with a particularly poor prognosis. After inducing remission with prednisone, vincristine and asparaginase, patients received cranial irradiation and IT methotrexate and were randomized to receive: 1--methotrexate alone; 2--methotrexate plus mercaptopurine; 3--same as in group 2 plus cyclophosphamide; and 4--same as in group 3 plus arabinosyl cytosine. Patients with CNS leukemia at diagnosis received IT methotrexate weekly during the induction period and a higher dose of CNS irradiation. Patients with anterior mediastinal enlargement at diagnosis received radiotherapy to the mass during the induction period. Patients who failed to attain bone marrow remission after four weeks of therapy were given daunorubicin and prednisone for 2--4 additional weeks. Of the 282 patients entering this study between January 1972 and November 1975, 268 (95%) attained complete remission and 228 (85%) were randomized to receive continuation chemotherapy with 1, 2, 3 or 4 drugs. In Group 1 (methotrexate alone), 14 of 20 patients relapsed and 9 developed leukoencephalopathy without antecedent CNS leukemia apparently due to higher doses of intravenous methotrexate; in Groups 2, 3 and 4 the results were equivalent, but without leukoencephalopathy in initial CR. The addition of cyclophosphamide and arabinosyl cytosine increased toxicity and complications without demonstrably increasing the leukemocidal effect. In the 40 patients given additional early therapy, the modalties employed in this study did not prolong remission.

Adolescent↗
PubMed1978

Phase I study of neocarzinostatin in children with cancer.

Twenty-three children with advanced cancer refractory to conventional therapy received weekly iv doses of neocarzinostatin for 5 weeks. Doses were escalated from 500 to 6750 units/m2/week. Four types of toxic manifestations occurred: acute reactions consisting of shaking chills with or without fever and cyanosis (rigor), hypersensitivity, vomiting, and marrow depression. Evidence of oncolytic activity was limited to patients with acute leukemia in whom phase II trials at doses between 3000 and 4500 units/m2 appear warranted.

Adolescent↗
PubMed1978

Combination chemotherapy for osteosarcoma.

Because of the great risk for development of pulmonary metastases following amputation for osteosarcoma, 24 consecutive patients with "clinically localized" osteosarcoma of an extremity were given adjuvant combination chemotherapy with adriamycin-cyclophosphamide-high-dose methotrexate-citrovorum factor. Thirteen of these patients remain free of tumor from 11 to 48 months following amputation. The median disease-free survival is estimated to be 18 months and the median survival 27 months. No relapses have been observed in any patients surviving free of disease beyond 23 months. Combination chemotherapy was also given to 16 patients whose disease was not localized; eight with pulmonary metastases at or following diagnosis, one with nodal metastases at diagnosis, two with osteosarcoma following radiation therapy for other malignant tumors, three with osteosarcoma of flat bones, one with parosteal osteosarcoma, and one with multifocal osteosarcoma. Three of this latter group of patients are surviving free of tumor at 8, 17, and 19 months from diagnosis. Two young patients died from complications of methotrexate and adriamycin toxicity.

Adolescent↗
PubMed1977

Adjuvant multiple drug chemotherapy for osteosarcoma of the extremity.

Results of treatment for osteosarcoma of the extremity have been poor with metastases usually causing death within 2 years following diagnosis. Because of the great risk of development of metastases, 20 patients have received adjuvant chemotherapy with Adriamycin, cyclophosphamide and high-dose methotrexate-leucovorin rescue for up to 12 months following amputation for osteosarcoma. Sixteen of these patients are surviving; 11 are free of evident tumor from 6 to 34 months following amputation. Five patients were found to have pulmonary metastases while receiving chemotherapy and three patients developed metastases following completion of chemotherapy. One patient died following her third treatment with high-dose methotrexate-leucorovin rescue. Other toxicity included nausea, vomiting, mucosal ulcerations, infections, hematologic abnormalities, changes in kidney and liver functions tests, and minor coagulation abnormalities. The natural history of osteosarcoma may have been modified by the use of these agents for periods exceeding the median time to predicted detection of pulmonary metastases. Microscopic metastases of some patients were eradicated by this adjuvant chemotherapy. For patients who developed metastases, these metastases were delayed in their time of detection and in their number at the time of detection.

Adolescent↗
PubMed1977

Colorectal carcinoma in adolescents implications regarding etiology.

Between October, 1974 and December, 1976, 13 adolescent patients with far-advanced, poorly differentiated colorectal carcinoma had been referred to a pediatric cancer center. All patients received chemotherapy with vincristine, methyl-CCNU and 5-fluorouracil. Five of 13 patients are living, one of whom remains disease-free after 12 months of chemotherapy. Four of the patients were from urban areas and nine from rural areas. One of four from urban areas had intimate exposure to chemicals used in the production of cotton and soy beans. Eight of nine patients from rural areas also had exposure to farm or agricultural chemicals, and three of these patients were intimately involved with the spraying operations. Suggestions regarding etiology and causative factors for the development of carcinoma of the colon in adults have previously been advanced. Results of these studies suggest that alternate etiologies must be suggested for adolescent colorectal carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1977

Osteosarcoma during pregnancy.

Four white women who developed osteosarcoma during pregnancy were referred for treatment, 2 prior to delivery and development of metastases, and 2 after delivery and development of metastases. After amputation, these patients received combination chemotherapy with either vincristine-cyclophosphamide or adriamycin-cyclophosphamide followed by high-dose methotrexate with leucovorin rescue. Two patients survived, 1 tumor-free and 1 with bony and soft tissue metastases. Management of pregnant patients with osteosarcoma should include the use of adjuvant systemic chemotherapy to prevent detectable metastases. This treatment should follow amputation or resection and early termination of pregnancy.

Abortion, Induced↗
PubMed1977

Epipodophyllotoxin VM-26 in the treatment of childhood neuroblastoma.

Thirteen children with disseminated neuroblastoma that had become refractory to conventional chemotherapy were treated with the epipodophyllotoxin VM-26. Three patients developed partial responses (greater than 50% reductions in tumors and in the proportion of tumor cells in bone marrow). Acute nonhematologic toxicity after treatment was minimal. Hematologic toxicity was observed but could not be assessed accurately since most patients had abnormal hematopoiesis due to extensive tumor involvement of bone marrow. These results demonstrate that VM-26, as a single agent, can produce measurable tumor responses in children with neuroblastoma.

Blood Cells↗
PubMed1976

Recurrent childhood lymphocytic leukemia following cessation of therapy: treatment and response.

A unique population of patients--children who developed recurrent acute lymphocytic leukemia (ALL) following cessation of initial prolonged therapy--was studied. During a 2-year period, 17 such children were admitted to a planned combination chemotherapy program. Complete bone-marrow remissions were achieved in 16 patients, and the median duration of second hematologic remissions was 216 days. These responses were significantly better than those obtained in seven patients who relapsed during the administration of continuation chemotherapy. Although the rate and duration of induced remissions were notably high, 9 of the 17 patients who relapsed off therapy have again developed recurrent leukemia. This result, together with the moderate toxicity encountered during treatment, indicates that more therapy is needed. The equal proportion of bone marrow and meningeal relapses was interpreted to mean that a secon course of preventive central nervous system therapy early in remission may be especially useful.

Adolescent↗
PubMed1976

Comparison of the clinical course of Hodgkin's disease in children and adolescents.

In this study the clinical features and response to therapy of 34 children, 4--10 years of age, and 54 adolescents, 11--20 years of age, were compared. The therapeutic response in patients in this series entered on a formal protocol was compared with nonstudy patients. The 2 age groups had similar sex ratios, characterized by male predominance, and age was not a determining factor in the extent of disease at diagnosis. By contrast, the distribution of histopathology varied between children and adolescents: mixed cellularity was most prevalent in the 4--10-year group (14/34), while nodular sclerosis predominated the older patients (23/55). Remission induction and duration were not age dependent, but remission duration did differ between study and nonstudy patients. Forty-five of 57 patients in the former group remain in continuous complete remission compared to 7 of 31 in the latter group. From these results we conclude that the clinical course of Hodgkin's disease is similar in children and adolescents and that the agressive therapy combined with careful staging used so successfully in adults should be adhered to in younger patients.

Adolescent↗
PubMedDate not supplied

4'-demethylepipodophyllotoxin 9-(4,6-o-2-thenylidene-beta-D-glucopyranoside) (NSC-122819; VM-26) and 4'-demethylepipodophyllotoxin 9-(4.6-0-ethylidene-beta-D-glucopyranoside) (NSC-141540; VP-16-213) in childhood cancer: preliminary observations.

We evaluated the responses of 39 children with cancer who, after failure to respond to conventional chemotherapeutic agents, received either or both of two epipodophyllotoxins: 4'-demethylepipodophyllotoxin 9-(4,6-o-2-thenylidene-beta-D-glucopyranoside) (NSC-122819) and 4'-demethylepipodophyllotoxin 9-(4,6-o-ethylidene-beta-D-glucopyranoside) (NSC-141540). Seventeen patients has acute lymphocytic leukemia (ALL). 12 had acute nonlymphocytic leukemia (ANLL), and ten had solid tumors. Initially, the patients in each disease category were randomized to receive 50 mg/m2/dose of NSC-122819 intravenously (iv) twice weekly or 75 mg/m2/dose iv of NSC-141540 twice weekly for 4 weeks. Drug dosages and schedules of administration were adjusted during the course of the study. Although objective responses were not detected in the heterogeneous group of solid tumor patients, definite clinical responses were obtained in nine of the 29 patients with acute leukemia. The responses to the two epipodophyllotoxins were noted in patients with ALL as well as in patients with ANLL. Toxic side-effects included nausea, vomiting, diarrhea, fever, alopecia, leukopenia, and thrombocytopenia. These results, the first reported with both NSC-122819 and NSC-141540 in childhood cancer, indicate that the epipodophyllotoxins are well tolerated and may be effective against acute leukemia.

Acute Disease↗