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Biomedical subjects

G R Buchanan

Publications and source records attributed to G R Buchanan.

At least 145 records · Page 8Linked to original sources
PubMed1988

Reinduction therapy in 297 children with acute lymphoblastic leukemia in first bone marrow relapse: a Pediatric Oncology Group Study.

Many children with acute lymphoblastic leukemia (ALL) develop a marrow relapse during or shortly following initial continuation chemotherapy. Achievement of a second complete remission is the initial step in a successful retreatment effort. Reinduction results using two or three drugs have been unsatisfactory, and previous reports of four-drug reinduction programs have included relatively small numbers of patients. Pediatric Oncology Group protocol 8303 was designed for patients with ALL in first marrow relapse during or within 6 months after cessation of chemotherapy. The results of reinduction therapy in 297 study patients are described here. Four-drug reinduction therapy consisted of daily oral prednisone, weekly vincristine and daunorubicin, and asparaginase three times weekly for 4 weeks (PVDA). CNS retreatment consisted of two doses of triple intrathecal chemotherapy. Of the 297 patients receiving reinduction, 245, or 82%, entered second complete remission, six died of infection or progressive disease, and 46 others still had M2 or M3 bone marrow status. Forty of these latter patients received four doses (during a 2-week period) of teniposide and cytarabine, after which 13 (32%) achieved complete remission status. Thus, the overall second complete remission rate with PVDA with or without teniposide/cytarabine was 258 of 297, or 87%. The treatment program was generally well tolerated. Among the numerous factors analyzed by using logistic regression, only female sex (P = .035), the presence of blasts on the blood smear at the time of relapse (P = .0002), and a length of initial complete remission less than 12 months (P = .021) were independent predictors of failure to enter second remission. We conclude that the intensive reinduction program described here is a highly effective first step in the delivery of salvage therapy to patients with ALL in first marrow relapse. The current challenge is to develop improved continuation treatment for these children.

Adult↗
PubMed1988

Reduced hemoglobin values in children and young adults with hemophilia.

Mild leukopenia and thrombocytopenia are common in multitransfused hemophiliacs. Because little attention has previously been directed to measurements of erythropoiesis in these patients, we prospectively examined hemoglobin concentration and RBC indices in 94 children and young adults with hemophilia during comprehensive clinic visits. Additional studies performed in many included serum transferrin saturation, ferritin, haptoglobin, and free erythrocyte protoporphyrin measurements. Hemoglobin concentrations were recorded as age-related percentile values. Hemophiliacs of all ages and degrees of severity often had lower than average values for hemoglobin; 31% had values less than the third percentile, 46% less than the tenth percentile, and 83% less than the mean value. Reduced hemoglobin percentile values were unrelated to age, severity of disease, or human immunodeficiency virus antibody status. Only five patients had an obvious cause for anemia. Serum ferritin, transferrin saturation, and erythrocyte protoporphyrin values were usually normal, indicating that iron deficiency and anemia of chronic disease were uncommon. Although serum haptoglobin was reduced in 44% of the patients, reticulocyte count was infrequently increased. We conclude that hemoglobin values are frequently less than the mean normal values for age in hemophiliacs. Although frank anemia is common, it is usually mild and without obvious cause. Hemophiliac individuals with slightly reduced hemoglobin values probably do not routinely require detailed investigation for occult blood loss, iron deficiency, or inflammation.

Adolescent↗
PubMed1987

Cytosine arabinoside/cyclophosphamide pulses during continuation therapy for childhood acute lymphoblastic leukemia. Potential selective effect in T-cell leukemia.

One hundred seventy-seven children with acute lymphoblastic leukemia (ALL) were admitted to a study designed to determine whether pulses of cytosine arabinoside (ara-C) and cyclophosphamide (cyclo) would improve disease-free survival (DFS). All patients received vincristine, prednisone, and asparaginase for remission induction, CNS prophylaxis with cranial irradiation and intrathecal methotrexate, and continuation therapy with 6-mercaptopurine plus methotrexate. Forty-seven of 101 patients with non-T ALL and 18 of 26 patients with T-cell ALL received ara-C/cyclo pulses every eight weeks during continuation therapy. The age, sex, and initial white cell count distributions were similar in both treatment groups. Patients with non-T-cell ALL had similar DFS with or without ara-C/cyclo pulses (36% versus 48%; P = 0.32). Ara-C/cyclo pulses significantly improved DFS in children with T-cell ALL (36% versus 0%; P = 0.015). Toxicities of the ara-C/cyclo pulses included reversible pancytopenia, drug induced fever, fever associated with neutropenia, and death in one patient from systemic candidiasis while neutropenic. This is the first clinical evidence to indicate that the combination of ara-C/cyclo used during continuation therapy is selectively beneficial in T-cell ALL.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Formation and disappearance of pocked erythrocytes: studies in human subjects and laboratory animals.

The pocked or "pitted" RBC count is being increasingly utilized as a test of splenic function. Since little is known about patterns of formation and removal of the characteristic organelles in the pocked RBC, we performed serial pocked RBC counts following splenectomy in six patients and in three animal species (dogs, rats, and rabbits). In the patients, pocked RBC counts began to rise within 1 week following splenectomy and reached a plateau (40-60%) by 60-100 days. Similar results were obtained following splenectomy of dogs, except that the plateau value was less. Pocked RBCs in splenectomized rats rose initially, but after the sixth week there was a progressive decline in their numbers; splenosis or accessory spleens were not visualized at autopsy. Rabbits had only a slight and inconsistent rise in pocked RBCs after splenectomy. When the rate of removal of pocked RBCs from the circulation was determined by transfusion of blood from splenectomized dogs in eusplenic animals, the pocked RBC count rapidly decreased within 3 to 6 hours. Pocked RBCs did not disappear when crosstransfused into a splenectomized recipient animal. Prior treatment of the recipient dog with either corticosteroids or vincristine did not affect the pattern of removal of pocked RBCs. We conclude that pocked RBCs rise slowly following splenectomy, disappear rapidly from the circulation in the presence of a normal spleen, and vary in pattern of rise and peak levels following splenectomy of different laboratory animals.

Animals↗
PubMed1987

Pocked erythrocyte counts in patients with hereditary spherocytosis before and after splenectomy.

The pocked (pitted or vacuolated) erythrocyte count has become increasingly utilized as a simple inexpensive test of splenic reticuloendothelial function. Values are less than 2.0% in normal subjects and 20 to 70% following splenectomy. Because scant and conflicting data are available about pocked erythrocyte measurements in hemolytic anemias other than the hemoglobinopathies, we performed pocked erythrocyte counts in 27 patients with hereditary spherocytosis. Prior to splenectomy patients often had elevated values (mean 4.9%). This unexpected observation suggests that hemolytic anemia may result in congestion of the red pulp and/or induced mild splenic reticuloendothelial blockade. As expected, but contrary to a previous report, pocked erythrocyte values following splenectomy were markedly increased (mean 54.9%).

Adolescent↗
PubMed1987

The nontreatment of childhood idiopathic thrombocytopenic purpura.

Despite the sudden and often alarming clinical manifestations of ITP, few patients in the pediatric age group develop serious complications or long-term sequellae. Conservative therapy, without use of pharmacologic or surgical intervention, is the most convenient, safe, and cost-effective approach in the vast majority of patients. There is a definite role for corticosteroids and IV gamma globulin in certain selected patients with both acute and chronic forms of ITP. Splenectomy may be of value in some chronically affected patients. Other forms of treatment are rarely if ever indicated. In summary, the best therapy for most children with ITP is no treatment at all.

Acute Disease↗
PubMed1987

Terminal deoxynucleotidyl transferase (TdT)-containing peripheral blood mononuclear cells during remission of acute lymphoblastic leukemia: low sensitivity and specificity prevent accurate prediction of relapse.

Serial samples of peripheral blood were obtained from 75 children with acute lymphoblastic leukemia in remission. An immunofluorescence assay was used to quantitate TdT-containing (terminal deoxynucleotidyl transferase-containing) cells in the mononuclear leukocyte fraction of these specimens. Nine relapses in 8 patients were preceded by elevations (0.12-0.70%) in peripheral blood terminal deoxynucleotidyl transferase-containing cells noted 1-33 weeks prior to relapse. No such elevations were observed prior to 6 relapses in 4 patients. Peripheral blood terminal transferase deoxynucleotidyl-containing cells were elevated (0.12-0.61%) in 22 children who did not relapse over a 5-82 week period of observation. The sensitivity (67%) and specificity (68%) of this assay are inadequate to establish which patients have minimal residual leukemia.

Child↗
PubMed1987

Hematologic alterations during acute infection in children with sickle cell disease.

In order to assess the hematologic features of acute bacterial infection in sickle cell anemia, we compared complete blood counts of 23 affected children with proven bacterial infection (Group A) to those of 22 patients with fever but without evidence of bacterial disease (Group B). Univariate and multivariate analyses of the data were carried out. Values for hemoglobin and platelet count were similar in Group A and Group B patients even though these measurements in both groups differed from base line steady state values. Absolute band counts were usually greater in Group A patients, but the sensitivity and specificity of elevated band counts as a diagnostic tool for bacterial infection were relatively low. We conclude that no aspect of the complete blood count can be used to guide major management decisions in febrile children with sickle cell anemia and potentially life-threatening infection.

Acute Disease↗
PubMed1986

Use of VP-16-213 in the treatment of familial erythrophagocytic lymphohistiocytosis.

Five patients with familial erythrophagocytic lymphohistiocytosis (FEL), aged 6 weeks to 3 years, were treated with VP-16-213. The drug dosage ranged from 100 to 200 mg/m2 administered biweekly until remission was achieved, and then at 1- to 3-week intervals as maintenance therapy. Intrathecal methotrexate was given to two patients with central nervous system involvement. All patients attained remission. Systemic relapses often ensued in all patients when VP-16-213 was delayed because of myelosuppression, or after attempts to lengthen the treatment interval, but they initially responded again to a more intensive chemotherapy schedule. To date, four of the patients died from disseminated disease and terminal infections 15 to 20 months from the time of diagnosis. One child is alive and well 20 months from diagnosis. Three of the dead children had become refractory to the drug. Our observations show that VP-16-213 induces remissions and prolongs survival in FEL. However, since the patients eventually become refractory to the drug and die of the disease, additional forms of therapy are required to improve the outlook of affected children.

Child, Preschool↗
PubMed1986

Pneumococcal septicemia despite pneumococcal vaccine and prescription of penicillin prophylaxis in children with sickle cell anemia.

Although polyvalent pneumococcal vaccine and prophylactic penicillin are used to prevent overwhelming Streptococcus pneumoniae septicemia in infants and young children with sickle cell anemia, infection rates remain high. We have reviewed our seven-year experience with a regimen of twice daily oral penicillin V potassium prophylaxis in 88 affected children. The median age at the start of prophylaxis was 10 months, and the median duration of prophylaxis was 29 months (range, three months to seven years). The total period of observation of patients who were prescribed penicillin was 248 person-years. Most patients also received one or two doses of polyvalent pneumococcal vaccine. Despite penicillin prophylaxis and pneumococcal vaccine, eight episodes of S pneumoniae septicemia have occurred and three have been fatal. Four episodes were in children older than 3 years. Suboptimal compliance with the prescribed oral penicillin regimen was usually apparent. With one possible exception, the infections occurred when penicillin had not been taken during the previous 24 hours. The S pneumoniae septicemia rate in this patient population, 3.2 per 100 person-years, is somewhat less than that described in previous reports of children not receiving penicillin but is still unacceptably high. Vigorous advocacy of a penicillin prophylaxis regimen does not eliminate the risk of pneumococcal septicema in this patient population.

Anemia, Sickle Cell↗
PubMed1986

Intravenous narcotic therapy for children with severe sickle cell pain crisis.

Few studies have been published about analgesic management practices during sickle cell pain crisis. Therefore, we reviewed the records of all hospitalized children with this complication during a recent five-year period. The 38 patients (98 painful episodes) who received intravenous narcotic therapy were the subjects of this review. In 76 patients, an initial intravenous bolus injection of morphine sulfate or meperidine hydrochloride was followed by a continuous intravenous infusion of one of these two drugs. To achieve adequate pain control, adjustments in infusion rates were made according to a written protocol. In 22 other patients, subsequent narcotic treatment consisted only of intermittent intravenous bolus injections of meperidine. Satisfactory pain relief was achieved in all 98 episodes. Patients given continuous infusions required more narcotic to control their pain and had more side effects than those treated with bolus injections alone, suggesting a dose-response relationship between narcotic dose and several known side effects. Common side effects included nausea and vomiting, lethargy, and abdominal distention. Although clinically evident respiratory depression was quite uncommon, chest syndrome was a frequent complication, and severe respiratory distress occurred in three patients. Narcotic withdrawal or addiction was not observed. With careful monitoring (including special attention directed to avoiding dosing error), continuous intravenous narcotic infusions are safe and provide effective pain relief for severe sickle cell pain crisis.

Adolescent↗
PubMed1986

Coagulation disorders in the neonate.

A review is presented of those aspects of hemostatic mechanisms that differ between neonates and older children. Practical laboratory tests to evaluate bleeding disorders in the newborn infant are discussed, as are the most frequently encountered primary and secondary conditions that affect hemostasis, both in the otherwise healthy newborn and in the sick low birthweight infant. Pathophysiology and treatment approaches will be briefly reviewed.

Blood Coagulation Disorders↗
PubMed1986

Juvenile chronic myelogenous leukemia: surface antigen phenotyping by monoclonal antibodies and cytogenetic studies.

Cells from three children with juvenile chronic myelogenous leukemia were studied using culture in semisolid media, cytogenetic analysis, and surface staining with the monocyte-specific monoclonal antibodies 61D3 and 63D3. The percentage of bone marrow mononuclear cells that were 61D3- and 63D3-positive was markedly increased in all three patients. Bone marrow and peripheral blood mononuclear cells exhibited exceptionally bright immunofluorescence with these antibodies. The presence of monocyte-specific antigens on the surface of juvenile chronic myelogenous leukemia cells suggests that they are derived from a precursor with monocytic characteristics. A specific chromosomal abnormality (47,XY+21) was present in fresh bone marrow cells from one patient; in contrast, 50 metaphases from phytohemagglutinin-stimulated peripheral blood contained a normal karyotype. The chromosomal abnormality was also identified in myeloid colonies grown in vitro from this patient. Granulocytic elements were demonstrated in tissue sections and in cultured myeloid colonies from this child. Our data suggest that malignant transformation in juvenile chronic myelogenous leukemia involves a myeloid progenitor population capable of differentiation in vitro to cells with monocytic or granulocytic characteristics.

Animals↗
PubMed1986

Acute chest syndrome in children with sickle cell disease. A retrospective analysis of 100 hospitalized cases.

We reviewed the clinical features of 100 cases of the sickle cell chest syndrome in 57 pediatric patients hospitalized with radiographic findings of pulmonary or pleural disease. Pulmonary infiltration was more common in the lower lobes (86%) than in the upper (25%) or middle lobes (22%). Pleural effusions were present in 38% of cases. Chest syndrome was recognized on presentation in 79% of cases, but was recognized only later in 21% of patients admitted for other indications. Patients recognized initially were more often febrile on admission (68%) than were subsequently recognized patients (33%) (p less than 0.01), but fever eventually occurred in 99 of 100 cases. Pain was an antecedent or coincident problem in 67% of cases. Median hospital stay was 7 days in those 58 cases in which narcotics were given, but only 4 days in those 42 cases in which narcotics were not administered (p less than 0.001). Polyvalent pneumococcal vaccine had been administered to 44 of our 57 patients at some time before their hospitalizations, and 18 patients had been on oral penicillin prophylaxis. Blood was cultured in 93 cases and in only two instances grew Streptococcus pneumoniae. Serologic evidence of Hemophilus influenzae type b infection was found in two additional patients. We conclude that the sickle cell chest syndrome is an acute febrile pulmonary disease frequently associated with pain and/or narcotic analgesic therapy but infrequently associated with proven bacterial infection.

Adolescent↗
PubMed1985

Plasma levels of platelet and vascular prostaglandin derivatives in children with sickle cell anaemia.

Platelet and vascular endothelial prostaglandin derivatives were measured by radioimmunoassay in the plasma of 39 children with homozygous sickle cell anaemia and 27 control subjects. The levels of both thromboxane B2 and 6-keto-PGF1alpha, the stable end-products of platelet and vascular prostaglandin metabolism, were significantly (p less than 0.001) greater in sickle cell anaemia plasma than in the plasma of the controls. There were no differences in levels of either 6-keto-PGF1alpha or thromboxane B2 between steady state and vaso-occlusive crisis in the sickle cell patients. Injury to the endothelial lining of blood vessels may occur in sickle cell anaemia as a consequence of contact with the abnormal erythrocytes.

Adolescent↗