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Biomedical subjects

H A Pearson

Publications and source records attributed to H A Pearson.

At least 73 records · Page 4Linked 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

Splenic function in sickle cell disease in the Eastern Province of Saudi Arabia.

The sickle cell disease that occurs in the Eastern Province of Saudi Arabia is reported to be clinically benign. It is biochemically characterized by high levels of fetal hemoglobin. Twenty-four Saudi patients with sickle cell disease were compared with 22 American patients. As a group, the Saudi patients were less anemic and had less hemolysis, microcytic RBC, and much higher levels of Hb F. Splenic function was assessed by enumeration of pocked RBC. Seventeen Saudi patients had low numbers of Pk RBC, indicating normal or nearly normal splenic function, whereas all American patients had markedly decreased splenic function and high numbers of Pk RBC. Low levels of Pk RBC were strongly associated with high levels of Hb F. The genetic basis of the milder sickle cell disease in Saudi Arabia has not been elucidated, but may involve multiple genetic factors. Although the sickle cell disease in Arab patients of eastern Saudi Arabia is often less severe than that in America, it is far from "benign," and some patients have severe clinical courses similar to those in patients in the West.

Adolescent↗
PubMed1984

Calvarial and phalangeal vascular impressions in thalassemia.

The nutrient foramina in the phalanges and/or the calvarial vascular markings were evaluated in 34 patients with thalassemia. Enlarged nutrient foramina were noted in 17 patients, and abnormal calvarial markings were observed in 19 patients. The prominence of the vascular changes in the phalanges paralleled those in the calvaria, and the calvarial vascular impressions correlated with the width of the skull. The enlarged superficial calvarial vessels associated with the vascular impressions may represent a hazard to the patient. A transfusion regimen from an early age seemed to prevent enlargement of these vascular impressions.

Adolescent↗
PubMed1983

Premature fusion of the proximal humeral epiphyses in thalassemia.

Premature fusion of the proximal humeral epiphyses with varus deformity is a common and characteristic radiologic finding in thalassemia anemia. A review of 17 cases with bilateral and one case with unilateral involvement, coupled with known anatomic and mechanical factors, suggested an explanation for this phenomenon. Hypertrophied marrow will thin the trabeculae and cortex, perforate the cortex through normal fenestrations, and proliferate subperiosteally. Normal force vectors result in medial humeral compression and ultimately premature fusion.

Adolescent↗
PubMed1982

Effect of iron saturation on the bacteriostasis of human serum: in vivo does not correlate with in vitro saturation.

Human serum inhibits the growth of a variety of human pathogens. One of the serum bacteriostatic components is transferrin, the major iron-binding protein. In the presence of transferrin, free iron, which is required for bacterial nucleoprotein synthesis, is unavailable and bacterial growth is inhibited. In an in vitro system, we tested the hypothesis that serum with highly saturated transferrin allows free iron to be available for rapid bacterial growth. We first confirmed the finding that addition of ionic iron sufficient to saturate transferrin in normal sera inhibits the bacteriostatic activity for Escherichia coli. In contrast, no differences were found in the growth rate of E. coli in sera from individuals representing the entire range of transferrin saturation found in humans (iron-deficient, normal, and thalassemic). This finding supports the thesis that iron added in vitro is more easily extracted than in vivo, where it is tightly bound to transferrin, and does not support the contention that ordinary iron treatment predisposes infants to infection.

Adolescent↗
PubMed1981

"Pure" cutaneous histiocytosis-X.

The case histories of two young children who experienced skin rashes involving various areas of the body are reported. The diagnosis of pure cutaneous histiocytosis-X was established after extensive studies revealed no other organ involvement. The patients were treated with oral corticosteroids. Currently, both children are in good health, show no evidence of disease, and have been followed over a four-to-five-year period. Therapy with corticosteroids may not be indicated with pure cutaneous histiocytosis-X unless there is evidence of extracutaneous dissemination or rapid progression of the disease.

Adrenal Cortex Hormones↗
PubMed1981

The ribs in thalassemia. I. The relationship to therapy.

A spectrum of rib changes was seen in 32 patients with thalassemia. Eleven patients had normal ribs, and 21 patients demonstrated at least one abnormality. The rib changes in patients who had been treated with a low transfusion regimen (designed to maintain the hemoglobin level at 5-6 g/100 ml) were compared with the changes in patients who had been treated with a hypertransfusion regimen (designed to maintain the hemoglobin level above 9.4-19 g/100 ml). Ten of the 11 patients (91%) with normal ribs were younger than five years when first hypertransfused, while only three of the 21 patients (14%) with abnormal ribs were younger than five. The type of rib abnormality was related to the age of onset of the low transfusion regimen. Those patients with abnormal but nonwidened ribs had been started on the low transfusion regimen earlier than those patients with the same abnormality and widened ribs. Fifteen of the 21 patients showed regression of the abnormal findings; approximately two thirds of the rib abnormalities did not regress until after the onset of a hypertransfusion regimen.

Adolescent↗
PubMed1981

The ribs in thalassemia. II. The pathogenesis of the changes.

In 32 patients with thalassemia the spectrum of rib changes, including widening, osteoporosis, localized lucencies, cortical erosions, "rib-within-a-rib" appearance, subcortical lucency, and extramedullary hematopoiesis, is reviewed. This material is supplemented by the radiographic and computed tomographic findings in a specimen of spine, posterior ribs, and extramedullary hematopoietic masses. The relevant literature on thalassemia, including two cases of "costal osteoma," is reviewed. A mechanism is offered to explain the various rib changes based on (a) the relationship of the proliferating marrow to the medulla, cortex, and periosteum, (b) the patient's age at the onset of a transfusion regimen, and (c) the type of transfusion regimen used.

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

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↗