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Biomedical subjects

A K Ritchey

Publications and source records attributed to A K Ritchey.

At least 37 records · Page 2Linked to original sources
PubMed1985

Developmental pattern of splenic dysfunction in sickle cell disorders.

Splenic function in sickle hemoglobinopathy syndromes was assessed to determine the developmental pattern of splenic dysfunction. Nonvisualization of the spleen using technetium-99 metastable (99mTc) spleen scans correlated strongly with pocked (vesiculated) RBCs greater than or equal to 3.5%. Cross-sectional analysis of pocked RBC data from 2,086 patients showed differences in the developmental pattern of splenic dysfunction between several disorders. In hemoglobin SS disease (sickle cell anemia) and hemoglobin S beta(0) thalassemia, splenic dysfunction (greater than or equal to 3.5% pocked RBCs) often occurred in the first 6 to 12 months of life. In hemoglobin S beta(+) thalassemia, splenic dysfunction occurred less frequently and later. Splenic dysfunction in hemoglobin SC disease (sickle cell-hemoglobin C) was intermediate. The level of pocked RBCs was inversely associated with fetal hemoglobin (P less than .007) and directly associated with age (P less than or equal to .001). These patterns of splenic dysfunction reflect the known severity of hemolysis and intravascular sickling and are consistent with the epidemiology of severe bacterial meningitis and sepsis in these diseases. Serial measurement of pocked RBCs permits determination of the onset of splenic dysfunction and the time of increased susceptibility to severe bacterial infections.

Age Factors↗
PubMed1984

Sideroblastic anemia: differences in bone marrow erythroid colony (CFUE) growth responses to erythropoietin in plasma clot and methylcellulose cultures.

Bone marrow cells from three patients with idiopathic acquired sideroblastic anemia and one with X-linked sideroblastic anemia were simultaneously cultured in plasma clot and methylcellulose cultures in order to evaluate their erythroid colony (CFUE) cloning potential in these two systems. In contrast to normals, sideroblastic anemia bone marrow cells demonstrated a marked ability to form erythropoietin (Epo)-independent CFUE in methylcellulose culture, and were inhibited in their ability to generate CFUE in plasma clot culture even in the presence of Epo. Addition of citrated plasma to methylcellulose cultures inhibited Epo-independent CFUE growth, but not Epo-dependent growth, by both a normal and patients' bone marrow cells. These results demonstrate that bone marrow cells from some patients with sideroblastic anemia can undergo Epo-independent and Epo-dependent CFUE growth in vitro, and that there is a marked difference in CFUE growth depending on the type of clonal culture method used. It is suggested that the culture microenvironment, plasma, and sensitivity to Epo may be contributing factors which allow specific clones of sideroblastic anemia CFUE-forming cells to proliferate in vitro.

Anemia, Sideroblastic↗
PubMed1981

Erythropoiesis during an erythroblastic transformation of chronic myelocytic leukemia.

The requirement of erythropoiesis for erythropoietin were studied in a patient with Ph chronic myelocytic leukemia who had undergone an erythroblastic transformation. Transfusions resulted in a suppression of erythropoiesis. Plasma clot culture studies indicated that both the CFU-E and BFU-E in the peripheral blood of this patient were dependent upon erythropoietin for their differentiation and proliferation. Neither of these committed erythroid stem cells was cloned in the absence of erythropoietin. These studies suggest that the proliferation and differentiation of erythroid stem cells during the erythroblastic crisis of this disorder remain dependent upon physiologic regulators.

Adult↗
PubMed1981

Posttranscriptional defects in beta-globin messenger RNA metabolism in beta-thalassemia: abnormal accumulation of beta-messenger RNA precursor sequences.

The production of beta-globin messenger RNA (mRNA) in beta-thalassemic erythroblasts was studied during pulse-chase incubations with [3H]uridine. Globin [3H]mRNA was quantitated by molecular hybridization to recombinant DNA probes complementary to globin mRNA and mRNA precursor sequences. Each of six patients with beta +-thalassemia produced normal amounts of globin alpha and beta [3H]mRNA during a 20-min pulse incubation, but the beta/alpha [3H]mRNA ratio declined to steady-state levels during a chase incubation, suggesting posttranscriptional defects in beta-globin mRNA metabolism. beta-globin mRNA precursor production was estimated by measurement of [3H]RNA sequences hybridizing to a pure DNA probe containing only the large intervening sequence (intron) of the beta-mRNA precursor. Four of the patients exhibited abnormal accumulation of 3H-beta-intron sequences (2-10 times normal), indicating abnormal posttranscriptional processing. In the remaining two patients, one of whom is known to carry a mutation in the small intron of the beta-globin gene, accumulation of large 3H beta-intron RNA and beta-globin [3H]mRNA was normal in nuclei, but the ratio of beta/alpha [3H]mRNA in cytoplasm was reduced, suggesting a different posttranscriptional defect in beta-mRNA processing. These findings imply the existence of heterogeneous posttranscriptional abnormalities in beta-globin mRNA metabolism in different patients with beta-thalassemia. The initial rates of gamma- and delta-mRNA synthesis were low in all patients, suggesting that the low level of expression of these genes in adults is mediated at the transcriptional level.

Adolescent↗
PubMed1980

In vitro steroid sensitivity testing: a possible means to predict response to therapy in primary hypoproliferative anemia.

We investigated the effects of various steroids on erythroid colony formation by normal human bone marrow and peripheral blood, and by marrow and peripheral blood from 18 patients with primary hypoproliferative anemia. These agents were variously found to enhance both CFU-E and BFU-E derived colony growth by normal human cells. Fluoxymesterone and dexamethasone were the most active inducers of CFU-E proliferation, and etiocholanolone and dexamethasone were the most potent burst augmenters. Androsterone did not significantly influence BFU-E proliferation in 66% of the marrow cultures from hematologically normal donors. Colony formation by erythroid progenitor cells of the patients with hypoproliferative anemia was reduce (20 +/- 10 CFU-E derived colonies/6 X 10(4) marrow cells; 12 +/- 5 BFU-E derived colonies/1 X 10(5) blood cells) when compared to growth by normal cells (65 +/- 14 CFU-E derived colonies/6 X 10(4) marrow cells; 21 +/- 9 BFU-E derived colonies/1 X 10(5) blood cells). Colony formation by marrow or peripheral blood cells of eight patients with steroid-responsive anemia was only moderately reduced (26 +/- 11 CFU-E derived colonies/6 +/- 10(4) marrow cells; 17 +/- 3 BFU-E derived colonies/1 X 10(5) blood cells) when compared to growth by marrow cells of three steroid-unresponsive patients (3 +/- 1.5 CFU-E derived colonies/6 X 10(4) cells). Whereas the addition of steroids of the same class to marrow and peripheral blood cultures of the steroid-responsive patients enhanced colony growth by 60-300%, their addition to marrow cultures of the steroid-unresponsive patients increased colony growth by less than 60%. It appears that further investigations using in vitro culture techniques as predictors of response to steroid therapy in patients with hypoproliferative anemia may be warranted.

Androstanes↗
PubMed1980

Hematology of beta-thalassemia trait--age-related developmental aspects and intrafamilial correlations.

Beta-thalassemia trait is a frequent cause of microcytic anemia in Mediterranean children. Because striking age-related changes occur in hemoglobin and mean corpuscular volume during childhood, we assessed developmental hematologic characteristics of 132 patients less than or equal to 18 years of age with beta-thalassemia trait. Thirty-nine kindred were studied to examine intrafamilial correlations of hematologic abnormalities. Patients with beta-thalassemia trait demonstrated Hgb values about 2 gm/dl below normal standards, with a progressive rise with age paralleling normal trends. Thalassemic MCV values showed a far greater deviation from normal than Hgb levels. In contrast to normal developmental trends which show a sharp increase in the first five years of life, the MCV in thalassemia trait showed no age-related increase prior to adolescence. No age-related changes in hemoglobin A2 levels were noted. Kindred studies demonstrate a correlation of the degree of anemia, microcytosis, and elevated hemoglobin A2 levels in affected family members (r = 0.318 P < 0.004, r = 0.525 P < 0.001, r = 0.416 P < 0.0015, respectively). Our findings support the use of electronically determined MCV values as an initial screening procedure for children with beta-thalassemia trait. Values of < 70 fl prior to adolescence and < 75 fl during adolescence were present in nearly all thalassemic subjects. Intrafamilial correlations of Hgb, MCV, and hemoglobin A2 levels suggest that these characteristics are genetically determined.

Adolescent↗
PubMed1980

Fever in young children with sickle cell disease.

Bacterial septicemia and meningitis are major causes of death in young children with sickle cell anemia. We report a prospective study of 182 episodes of fever among 22 children with sickle cell diseases identified at birth. The majority of patients with fever exceeding 39.5 degrees C were treated with antibiotics intravenously until results of blood cultures were known. Infectious diseases were documented in 38% of all febrile events. Six episodes of bacterial septicemia, two associated with meningitis, were successfully treated with no mortality or residual morbidity. These data form the basis of suggestions for management of the young child with sickle cell disease and fever.

Anemia, Sickle Cell↗
PubMed1980

Prenatal diagnosis of beta-thalassemias by amniocentesis: linkage analysis using multiple polymorphic restriction endonuclease sites.

In order to assess the applicability of multiple restriction endonuclease analyses of amniocyte DNA to the prenatal diagnosis of beta-thalassemias in general, we studied 12 consecutive couples at risk. DNA of both members of the 12 couples and a previous offspring of each was analyzed for the presence of 4 polymorphic restriction endonuclease sites: the Hpa I site 3' to the beta-globin gene, the Hind III site in the G gamma gene, the Hind III site in the A gamma gene, and the Bam HI site 3' to the beta-gene. Linkage disequilibrium between these sites and beta A or beta thal genes was not found, presumably due to the heterogeneity of beta thal genes. However, the high frequency of polymorphism at these sites allowed differentiation of beta A-bearing chromosomes from beta thal or beta S-bearing chromosomes in both members of 6 couples. In these couples, complete prenatal diagnosis by linkage analysis of amniocyte DNA would be possible. In the remaining 6 couples, beta A and beta thal chromosomes could be discriminated in one member. In about 50% of the pregnancies of these couples, exclusion of beta-thalassemia is possible by this analysis. These data suggest that when linkage analysis of polymorphic restriction endonuclease sites is carried out, prenatal diagnosis of beta-thalassemia states can be accomplished by amniocentesis alone in 75% of pregnancies at risk.

Amniocentesis↗
PubMed1979

Antibody-mediated acquired sideroblastic anemia: response to cytotoxic therapy.

A 5 1/2-yr-old child developed severe anemia with erythroid hypoplasia and 50% ringed sideroblasts in his bone marrow. A serum inhibitor of erythropoiesis was demonstrated, utilizing syngeneic and autologous bone marrow in a plasma-clot culture system. The IgG fraction of the patient's serum effected similar suppression of erythroid colony formation. Prednisone therapy was ineffective, but following treatment with cyclophosphamide, normal erythropoiesis was established, ringed sideroblasts disappeared, and his serum no longer inhibited erythropoiesis in vitro. Cyclophosphamide was discontinued, and the patient has remained hematologically normal. This patient is an example of antibody-mediated sideroblastic anemia successfully treated with a cytotoxic drug.

Anemia, Sideroblastic↗
PubMed1975

Fever of unknown origin and the value of gallium-67 and technetium-99M for defining abnormality of the spleen: a case report.

A three-year-old white female with acute promyelocytic leukemia developed persistent fever after successful induction-remission therapy; many large monilial abscesses were later found in the grossly enlarged spleen. Although the technetium-99M sulfur colloid scan prior to splenectomy suggested only a slight abnormality of the spleen, the gallium-67 citrate scintigraph showed a marked increase in gallium accumulation. The disparate results of the scanning techniques utilized in this patient suggest that it may be necessary to use more than one type of radiopharmaceutical to define an enlarged spleen, as well as the pathological process responsible for its enlargement.

Abscess↗
PubMedDate not supplied

An unusual histiocytic disorder responding to cyclosporine therapy: a case report.

PURPOSE: To describe the clinical and pathologic presentation and course of a 7-week-old girl with anemia, thrombocytopenia, and organomegaly who was found to have a histiocytic disorder distinct from previously reported cases. METHODS: Bone marrow specimens were studied with conventional methods. A liver biopsy specimen was evaluated by routine and immunohistochemical methods and electron microscopy. RESULTS: The patient was found to have a unique histiocytic disorder in which lesional cells displayed an atypical phenotype. Cyclosporine therapy was associated with a prompt, complete, and apparently permanent resolution of disease. CONCLUSION: This case appears to represent an atypical histiocytic disorder with unique clinical and pathologic features. The disorder resolved after the initiation of cyclosporine therapy.

Anemia↗
PubMedDate not supplied

Individual differences in pediatric cancer patients' reactions to invasive medical procedures: a repeated measures analysis.

Previous research on child distress in pediatric cancer has addressed the issue of habituation to invasive procedures using correlational methodology. In addition, most studies have focused on the bone marrow aspiration (BMA); few have examined children's reactions to the lumbar puncture (LP) separately. The present investigation examined 13 pediatric cancer patients over time as they experienced five BMAs or LPs. Direct observation of child behavior during procedures was employed to assess distress responses using a 12-category measure. Individual patients demonstrated a range of distress patterns. Only two children were observed to habituate to these procedures. The importance of individual patient characteristics and differences in the execution of the procedures are discussed, as is the need for greater use of treatments for child distress.

Analysis of Variance↗
PubMedDate not supplied

Variable in vitro erythropoiesis in patients with transient erythroblastopenia of childhood.

Transient erythroblastopenia of childhood (TEC) is a pure red cell aplasia which primarily affects children in the infant and toddler age group. The clinical syndrome of TEC is well defined and is characterized by moderate to severe anemia with reticulocytopenia, selective aplasia of the erythroid bone marrow elements, and spontaneous recovery, usually within a month of presentation. We utilized the plasma clot tissue culture technique to explore the defect of erythropoiesis in seven patients with TEC. Culture of bone marrow at diagnosis in four patients revealed an increased erythroid proliferative capacity in one and a decreased capacity in three. The former patient plus three additional patients were found to have a transient serum inhibitor of erythroid colony formation in autologous and allogeneic systems. The three patients with diminished erythroid proliferative capacity had no demonstrable serum inhibitor, and in one patient studied the erythroid proliferative capacity became supernormal after recovery. We conclude that although TEC has a characteristic clinical picture, in vitro studies reveal a variable expression of the erythropoietic defect and support the hypothesis of a heterogeneous pathogenesis of this disorder.

Anemia↗
PubMedDate not supplied

The proliferative capacity of pure red cell aplasia bone marrow cells.

Pure red cell aplasia (PRCA) is a heterogeneous disorder. Immunologic abnormalities have recently been uncovered suggesting that both cell-mediated and humoral immune mechanisms may be of etiological importance in PRCA. Utilizing a technique for the cloning of bone marrow erythroid precursors, we determined the in vitro proliferative capacity of erythroid cells obtained from 21 patients with PRCA. Bone marrow cells from one group of patients produced normal or increased numbers of erythroid colonies while the in vitro proliferative capacity of bone marrow cells from a second group was characterized by subnormal erythroid colony formation. Sera obtained from the former group was frequently associated with demonstrable serum inhibitors of erythropoiesis, while PRCA in the latter group was probably the consequence of intrinsic erythroid stem cell defects or pathologic cellular interactions with nonerythroid regulatory cells. This survey of a relatively large population of patients with PRCA provides evidence for the multiple causative mechanisms that can be operative in the production of PRCA.

Adolescent↗