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Biomedical subjects

G R Buchanan

Publications and source records attributed to G R Buchanan.

At least 163 records · Page 9Linked to original sources
PubMed1985

Extravasation of dactinomycin, vincristine, and cisplatin: studies in an animal model.

Extravasation of some cytotoxic drugs results in chemical cellulitis. Management of suspected extravasation has been empiric and difficult to evaluate clinically. We investigated dactinomycin, vincristine, and cisplatin by means of intradermal injections in Balb-c mice. Reproducible skin lesions with concentric areas of induration, erythema, and ulceration developed in a time- and dose-dependent fashion following injection of dactinomycin. Vincristine caused no lesions following initial intradermal administration, but repeat injection 7 days later was followed by a diffuse punctate ulcerative lesion suggesting a hypersensitivity reaction. Three concentrations (1.0, 0.1, and 0.01 mg/ml) of cisplatin elicited cellulitis following initial injection, but there was no correlation between lesion size and dose. Injection of saline, hydrocortisone, ascorbic acid, sodium thiosulfate, buffered DNA solution, and beta adrenergic agonists and antagonists after the injection of dactinomycin failed to prevent development of lesions. Heat application was also ineffective; however, local cold application prevented or markedly reduced reactions to dactinomycin. We conclude that the intradermal mouse model may be appropriate for the evaluation of the three drugs studied and that cold application is the best antidote among those tested for dactinomycin-induced ulceration in this model.

Adrenal Cortex Hormones↗
PubMed1985

Diamond-Blackfan syndrome in adult patients.

Two adults with pure red cell aplasia are described. No extrinsic etiologic mechanisms were identified. Evidence of anemia was long-standing and varied in severity. Musculoskeletal abnormalities (webbed neck, Sprengel's and Klippel-Feil deformities, and hand abnormalities) were similar to those seen in the congenital form of red cell aplasia (Diamond-Blackfan syndrome). As in the congenital variety, adrenal cortical steroids resulted in hematologic repair. These observations suggest that congenital (Diamond-Blackfan) pure red cell aplasia may be first recognized in adulthood and that steroids provide a potential therapeutic modality.

Adult↗
PubMed1985

Splenic reticuloendothelial function in children with cancer.

We studied splenic function in children with cancer by quantitation of pitted, or pocked, erythrocytes (pocked RBC count), that is, the percentage of erythrocytes containing one or more membrane-bound vesicles, as determined by phase interference microscopy. The mean pocked RBC count in 93 normal children and adults was 0.49% (range 0% to 2.0%), with only 2.4% of normal subjects having values greater than 1.5%. Mean pocked RBC count in 28 children after splenectomy was 37% (range 3.2% to 81%). Among 181 children with cancer (525 specimens), the mean pocked RBC count was 1.06% (range 0% to 12.6%). Fifty-nine (32%) patients had one or more values greater than 1.5%, and 25 (13.8%) children had measurements greater than 3.0%, a level previously suggested to have clinical significance. Elevated pocked RBC counts (greater than 1.5%) occurred in more than one third of children with Wilms tumor and acute lymphoblastic leukemia, and in both patients with juvenile chronic myelogenous leukemia. Elevations in pocked RBC counts were not related to specific chemotherapy regimens or to disease activity. Mild splenic reticuloendothelial hypofunction occurs in many children with cancer and may contribute to the risk of infection in these patients.

Acute Disease↗
PubMed1984

Lymphocyte populations in childhood idiopathic thrombocytopenic purpura.

Altered immune function has previously been reported in children with idiopathic thrombocytopenic purpura (ITP). Some prior studies have shown that acute and chronic ITP might be differentiated by certain immunologic tests. We investigated lymphocyte subsets in 12 children with ITP (six acute and six chronic) using murine monoclonal antibodies. Although the mean percentages of B lymphocytes and total number of T lymphocytes, suppressor T cells, and helper T cells were similar in patients with acute and chronic ITP and in controls, the values for many children with ITP fell outside of the normal range. The distribution of values was similar among the patients with acute and chronic ITP. These results suggest a heterogeneous nature of immune-mediated thrombocytopenia in childhood.

Adolescent↗
PubMed1984

Effect of penicillin prophylaxis on nasopharyngeal colonization with Streptococcus pneumoniae in children with sickle cell anemia.

Polyvalent pneumococcal vaccine and oral penicillin prophylaxis are frequently used in patients with functional or anatomic asplenia to protect them from fulminant Streptococcus pneumoniae sepsis. We studied nasopharyngeal colonization with pneumococci in 34 patients with sickle cell anemia (aged 6 months to 5 years) receiving penicillin prophylaxis and in 63 age- and race-matched comparison patients. Patients with sickle cell anemia had fewer positive initial pneumococcal nasopharyngeal cultures than did the comparison group (14.5% vs 34.4%, P = 0.03) and significantly lower carriage rates during the respiratory illness season of November to March (8.7% vs 40.5%, P = 0.005). Penicillin prophylaxis did not result in emergence of penicillin-resistant pneumococci or in an increased carriage rate of Haemophilus influenzae type b. Our data suggest a mechanism of action for penicillin prophylaxis and provide some evidence for the relative safety of this regimen.

Anemia, Sickle Cell↗
PubMed1984

Prednisone therapy for children with newly diagnosed idiopathic thrombocytopenic purpura. A randomized clinical trial.

The efficacy of corticosteroids in childhood acute idiopathic thrombocytopenic purpura (ITP) is controversial and has infrequently been evaluated in a controlled randomized fashion. We administered prednisone (2 mg/kg/day for 14 days with subsequent tapering and discontinuation by day 21) or placebo to 27 children, aged 10 years or less, with newly diagnosed ITP. Platelet count, bleeding time (a test of the integrity of the platelet-microvasculature interaction), and clinical bleeding score (based on a 0-4 scale) were determined before (day 0) and six times following initiation of drug therapy (days 1-2, 3-5, 7, 14, 21, and 28). There were no statistically significant (p less than 0.05) differences between the two treatment groups in any of the three study parameters except on day 7 of therapy when children receiving prednisone had higher platelet counts and lower bleeding scores and bleeding times than those taking placebo. Bleeding time correlated inversely with the platelet count in both treatment groups. Prednisone did not appear to influence bleeding time independent of its effect on platelet count. This treatment regimen of prednisone did not clearly improve hemostasis in childhood acute ITP except transiently at the end of 1 week of treatment.

Bleeding Time↗
PubMed1984

Mild splenic sequestration crises in sickle-hemoglobin C disease.

Acute splenic sequestration crisis ( ASSC ), a common complication in homozygous sickle cell anemia, has been described infrequently in sickle-hemoglobin C (SC) disease in the absence of high altitude exposure. In this report, we describe three children with hemoglobin SC disease who developed episodes of ASSC that were milder than those generally described in sickle cell anemia. In one patient, an antecedent triggering event was not recognized. The other two children may have had a predisposing cause for massive intrasplenic sickling in that one had an associated mononucleosis syndrome and the other an episode of hypovolemic shock following severe epistaxis. ASSC may occur in patients with SC disease and does not necessarily require a hypoxic trigger associated with high altitudes.

Acute Disease↗
PubMed1984

Direct transfer of adult hookworms (Ancylostoma duodenale) from dog to child for therapeutic purposes.

To induce chronic and continuous intestinal blood loss as therapy for congenital polycythemia in a 3 year old child, adult Ancylostoma duodenale were transferred directly from a dog to the patient via a nasoduodenal tube. By transferring adult worms, larval migration via the skin, blood and lungs--with possible attendant undesired side effects--was avoided. Furthermore, by eliminating larval migration with associated intimate tissue contact, immunogenicity was presumably reduced, and a known number of adult worms could be delivered directly to the final predilection site, the small intestine. An eosinophilic reaction of up to 23,000 cells/mm3 was observed, which may have adversely affected attempted superinfection. The relatively small numbers of parasites given on three separate occasions did not result in blood loss to a degree sufficient to eliminate the need for other forms of therapy.

Ancylostomiasis↗
PubMed1983

Chromosomal translocation involving the immunoglobulin kappa-chain and heavy-chain loci in a child with chronic lymphocytic leukemia.

Chronic lymphocytic leukemia is usually a monoclonal B-cell neoplasm that occurs almost exclusively in middle-aged and elderly adults. We observed a rapidly progressive case of the disease in a 10-year-old girl. The leukemic cells bore surface IgM and IgD immunoglobulins of the kappa-light-chain type. Karyotyping of the abnormal cells revealed an unusual translocation [t(2;14) (p13;q32)], with break points at or near the kappa-light-chain and heavy-chain gene loci. Translocations involving the immunoglobulin gene loci may be important in the pathogenesis of some cases of chronic lymphocytic leukemia, as they appear to be in Burkitt's lymphoma.

Child↗
PubMed1983

Transfusion-associated cytomegalovirus infection and acquired immune deficiency syndrome in an infant.

An infant who received multiple blood transfusions in the neonatal intensive care unit developed a transfusion-associated CMV infection at age 11 weeks and thereafter was noted to have hepatosplenomegaly, mitogen hyporesponsiveness, persistent viruria, an abnormal distribution of T-lymphocyte subpopulations, and poor growth. He has had recurrent opportunistic infections, including Pneumocystis carinii pneumonia. Six donors of blood products received by this infant were investigated; one was found to have chronic lymphadenopathy, weight loss, intermittent diarrhea, lymphopenia, and a profound depression of lymphocytes with a helper/inducer surface phenotype (T4 positive). Family members have an abnormal distribution of T cell subpopulations similar to those reported in asymptomatic homosexuals. The course of disease in our patient suggests that acquired immune deficiency syndrome may be transmitted to young infants via blood products.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Evidence against enhanced platelet activity in sickle cell anaemia.

Although numerous studies have provided indirect evidence for enhanced platelet activity in sickle cell anaemia, little attention has been directed to examination of platelet alpha and dense granule release in the sickling disorders. We simultaneously measured by radioimmunoassay plasma levels of the alpha granule constituents beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) in 43 children with sickle cell anaemia in steady state and 24 patients during severe vaso-occlusive crisis. beta-TG levels during steady state (50 +/- 3.6 ng/ml, mean +/- SEM) were greater (P less than 0.001) than in normal controls (36 +/- 1.6), but there was no additional significant rise during crisis (55 +/- 5.9). PF4 levels were similar (P = 0.12) in both steady state (10 +/- 1.2 ng/ml) and crisis (9.3 +/- 2.3) to those of normal controls (6.0 +/- 0.8). The similarity of beta-TG/PF4 ratios in normal and sickle cell anaemia patients as well as the positive correlation (P less than 0.05) between platelet count and beta-TG and PF4 suggested that an artefactual in vitro platelet activation was responsible for some of the observed increased beta-TG and PF4 levels. Further evidence against enhanced platelet activity in these sickle cell patients included normal intraplatelet content of the dense granule constituent 5-HT and a normal ATP/ADP ratio. From this data we conclude that platelet activation in children with sickle cell anaemia appears minimal.

Adolescent↗
PubMed1983

Plasma and erythrocyte lipids in sickle cell anaemia.

The content and composition of plasma and erythrocyte lipids from individuals having sickle cell anaemia has been determined. The plasma contains a significantly reduced content of both cholesterol and phospholipid while the ratio of cholesteryl ester to total cholesterol, the distribution of phospholipid classes, triglyceride concentration and the fatty acid content were similar to normal values. However, the free glycerol content of the plasma was eight-fold higher than normal. Erythrocyte lipids contain an elevated level of cholesterol and control levels of phospholipid content, phospholipid distribution and fatty acid content. The plasma was separated by ultracentrifugation into VLDL (density less than 1.006), LDL (1.006 less than d less than 1.063) and HDL (1.063 less than d less than 1.21). Significant decreases in cholesterol and phospholipid were observed in LDL and HDL.

Adolescent↗
PubMed1983

Relative hyperglucagonemia in L-asparaginase-and prednisone-induced glucose intolerance in management of acute lymphocytic leukemia.

Ten children with acute lymphocytic leukemia developed transient diabetes mellitus during treatment with L-asparaginase and prednisone. Serum glucose, plasma insulin, and plasma glucagon levels were measured when the patients were hyperglycemic. Six of the children were restudied several months later when there were no clinical or laboratory signs of glucose intolerance. Hyperglycemia induced by L-asparaginase and prednisone was associated with depression of plasma insulin and, despite the inhibiting action of L-asparaginase on protein synthesis, a corresponding elevation of plasma glucagon. Thus patients with diabetes mellitus induced by L-asparaginase and prednisone have relative hyperglucagonemia similar to other patients with diabetes mellitus.

Adolescent↗
PubMed1983

Bacterial infection and splenic reticuloendothelial function in children with hemoglobin SC disease.

Although the epidemiology and pathophysiology of serious bacterial infection in homozygous sickle cell anemia (SS disease) have become increasingly well understood, information about infection risk and splenic reticuloendothelial function in hemoglobin SC disease is quite limited. Therefore, the type and frequency of invasive bacterial disease were examined in 51 children with SC disease followed for 370 person-years and splenic function was assessed in 31 patients by quantitation of pitted erythrocytes. Seven serious bacterial infections occurred in four of the patients, five due to Streptococcus pneumoniae and two to Haemophilus influenzae. A primary focus of infection was present in all episodes, none of which proved fatal. Although 30 episodes of pneumonia or chest syndrome occurred in 20 of the patients, a bacterial etiology was proven in only three instances. Splenic function was usually impaired, with a mean pit count of 7.1% +/- 8.2% (range 0% to 22.9%). This is significantly greater than normal, but less than pit counts in patients with SS disease or asplenic subjects. Children with SC disease may have a greater risk of bacterial infection than normal children, but their infection rate is not nearly as high as that in patients with SS disease.

Adolescent↗