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Biomedical subjects

D Powars

Publications and source records attributed to D Powars.

At least 19 recordsLinked to original sources
PubMed1990

Delayed intracranial hemorrhage following cerebral infarction in sickle cell anemia.

Clinical and necropsy findings in 11 patients with sickle cell anemia (SS) indicate that intracranial hemorrhage (IH) is a delayed sequela of the same vasculopathy that causes cerebral infarction during childhood. Evidence of prior cerebral infarction during childhood included hemiparesis, seizures, an episode of coma, or mental retardation. Computerized tomography (CT) scans showed cerebral infarcts with lucent areas and dilated ventricles or cerebral atrophy. CT or magnetic resonance imaging (MRI) scans after the intracranial hemorrhage demonstrated intraventricular or intracerebral hemorrhages. Angiography or autopsy in seven patients showed widespread vascular occlusion and narrowing of arterial vessels. Moyamoya with internal carotid artery occlusion was identified in two cases. At the time of the IH, three patients were being treated with prophylactic transfusion regimens. We hypothesize that the central nervous system vasculopathy progresses over time and that arterial narrowing in both large and small vessels secondary to endothelial hyperplasia is followed by neovascularization and hemorrhage. Recognition of this pattern of delayed intracranial hemorrhage following cerebral infarction should encourage more intensive evaluation aimed at developing rational interventional therapy prior to a terminal intracranial hemorrhage.

Adolescent↗
PubMed1979

Childhood leukemia and lymphoma: correlation of clinical features with immunological and morphological studies.

Malignant cells from 49 children with lymphoid neoplasms other than Hodgkin disease were evaluated by surface marker and morphologic studies. We classified the patients into three groups: 36 patients (74%) with acute lymphocytic leukemia; 7 (14%) classified as convoluted lymphocytic lymphoma/leukemia; and 6 (12%) with small noncleaved follicular center cell lymphoma/leukemia. Diffuse marrow involvement was present at diagnosis in some patients in the latter two groups, but their clinical course was not characteristic of the patients with acute lymphocytic leukemia. Male predominance, poor prognosis, and high incidence of central nervous system disease characterized patients in the convoluted lymphocytic and follicular center cell lymphoma/leukemia groups. Clinical presentation in these two groups differed. Proliferations of convoluted lymphocytes were associated with mediastinal masses and proliferations of follicular center cells with intraabdominal tumors. The high incidence of CNS disease in children with neoplasms of convoluted lymphocytes and follicular center cells suggests that these processes have a predilection for the CNS and that patients with them may benefit from CNS prophylaxis.

Adolescent↗
PubMed1979

Hemoglobin Sunshine Seth - alpha 2 (94 (G1) Asp replaced by His) beta 2.

Hemoglobin Sunshine Seth in which a histidyl is substituted for an aspartyl residue at position 94 of the alpha chain was detected at birth in a Caucasian male infant during cord blood screening and is present also in the mother and a male sibling. Although the substitution is in the alpha 1 beta 2 contact, it is without obvious deleterious effect on the hematological parameters or the health of the affected individuals.

Amino Acids↗
PubMed1977

Bacterial meningitis and septicemia in sickle cell disease.

A total of 422 patients with sickle cell disorders have been observed for 3,442 patient years. During this period, 53 episodes of septicemia or meningitis occurred, indicating a risk of 12.5% from these infections for each individual. If only patients with SS hemoglobinopathy (sickle cell anemia) (323 patients) are considered, the risk was 15.2%. The case fatality ratios for sepsis and meningitis were 35% and 10%, respectively. Disease due to Streptococcus pneumoniae occurred, almost exclusively, among children with SS hemoglobinopathy who were less than 5 years of age. After the first decade, illnesses among patients with all types of sickle cell disorders were frequently associated with an identifiable source of infection, a chronic course, and frequent involvement of Gram-negative organisms.

Adolescent↗
PubMed1977

Severe coagulation abnormalities in Reye syndrome.

Coagulation studies were performed on 13 children with clinical diagnoses of Reye syndrome. Four had abnormalities so severe that transfusion of coagulation factors and platelets were required prior to percutaneous liver biopsy. In one of these, abnormalities frequently found in association with acute hepatic failure were present. Disseminated intravascular coagulation was noted in two, while in the fourth child laboratory data were most consistent with that process. Although the coagulation defect associated with Reye syndrome is most often due to decreased production of all coagulation factors except VIII, these patients demonstrate that consumption can also occur. The severity of the coagulopathies found indicates that bleeding can become a major complication in the diagnosis and management of Reye syndrome.

Blood Coagulation Disorders↗
PubMed1977

On the birth of an infant with sickle cell anemia.

This is the first report in the English literature of the birth of an obligate SS infant whose parents both had sickle cell anemia. The young adult SS parents of this infant and their families did not wish to prevent the birth of this child but had, in fact, many positive reasons to continue the pregnancy to term even in the face of the increased personal risk of pregnancy for this mother. This unusual circumstance initiated a re-appraisal of the realistic expectations with respect to reproduction in patients with homozygous recessive genetic disorders. No definitive studies could be found which attempted to evaluate the influence of genetic counseling on reproductive behavior in patients with sickle cell anemia. The questions raised about the 'right to reproduce' and the realistic aims of genetic counseling in adult homozygote patients have been discussed. However, no conclusions seem warranted because of the paucity of available information.

Adult↗
PubMed1977

Congenital malaria: a rare cause of splenomegaly and anemia in an American infant.

A 38-day-old infant had fever, jaundice, hepatosplenomegaly, and a hemolytic anemia. A peripheral blood smear demonstrated intraerythrocytic malarial parasites identified as Plasmodium vivax. Maternal and infant sera contained antibodies to this species. A directed history revealed the mother had suffered several febrile illnesses in Mexico during her pregnancy. Malaria had not been diagnosed nor was it considered at the time of her delivery at this hospital. Review of this and six other cases of congenital malaria reported in this country since 1950 indicates clinical manifestations seldom appear before 3 weeks of age. Although these signs are more frequently associated with other transplacental infections, their occurrence in an infant whose mother is from or who has traveled in an endemic area should prompt consideration of the diagnosis of congenital malaria.

Adult↗
PubMed1977

Severe iron deficiency anemia.

Severe iron deficiency anemia remains a continuing major health hazard among inner city children in Los Angeles. Over a 24-month period, 60 children in whom hemoglobin values were below 7 grams per dl were admitted to hospital; 11 (18 percent) of them were in overt congestive heart failure. Contrary to the popular conceptions, two thirds of the anemic children were undernourished, approximating the 16th percentile for weight on the Iowa growth chart, and the frequency of premature birth was not greater than in the general population. There were no deaths in this series. A management protocol which included partial exchange transfusion of children in congestive heart failure and supportive transfusion for children with hemoglobin levels below 5 grams per dl was employed.

Anemia, Hypochromic↗