1/6. Altered erythropoiesis and increased hemolysis in hemoglobin m Akita (M Hyde Park beta92 His replaced by Tyr) disease.Hb M Akita disease is a cyanotic hemoglobinopathy found in Akita Prefecture, japan. The abnormal hemoglobin was found to be the same as Hb M Hyde Park (beta92 His replaced by Tyr) by chemical analysis in 1967. In this disease signs of accelerated hemolysis (serum bilirubin, 2.4 mg/dl; splenomegaly, 2 finger breadths; Hb, 10.7 g/dl; reticulocyte index, 2.7) were noted, but the causes of its slight anemia were revealed to be fairly complex by ferrokinetic study, RBC life-span measurement, and 99mTc myeloscintigram. The anemia in this disease is caused not only by shortened erythrocyte survival (T 1/2 = 11.5 days by 51Cr-tagging method) and sequestration of red cells in the spleen (spleen: liver ratio = 2.5 approximately 3.0 by 51Cr-surface counting), but also by slow supply of erythrocytes to the peripheral blood from the bone marrow, presumably, related to the existence of unstable Hb M Akita and its derivative (Hb Akita) in the erythroid cells. Both Carrell's isopropanol test and Heinz body formation test were positive. In spite of maximally increased total erythropoiesis (8 times as high as the normal level; M:E ratio = 0.22:1.0), supply of red cells from the bone marrow to the peripheral blood was significantly decreased. The distribution of hematopoietic sites throughout the body was reasonably uniform.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
2/6. Hb-M "Hyde Park": a de novo mutation, identified by mass spectrometry and dna analysis.BACKGROUND. Structural hemoglobinopathies usually are inherited as autosomic dominant traits; de novo mutations are uncommon. Analytical and preparative procedures for the characterization of an abnormal hemoglobin are complex and time-consuming. Mass spectrometer analysis allows a rapid identification of the amino acid substitution. methods AND RESULTS. A cyanotic 7-year-old girl was found to have 16% methemoglobin. Laboratory data showed the presence of an abnormal hemoglobin, which was isolated by collecting the abnormal peak from DEAE and globin chains from CM52. The amino acid substitution was rapidly identified by FAB mass spectroscopic analysis, leading to the recognition of HbM Hyde Park. These data were confirmed by molecular analysis (Southern blot and dna sequencing). Neither the parents nor a sister showed any abnormality; non-paternity was excluded by blood group serology and HLA typing. CONCLUSIONS. This is a case of HbM Hyde-Park arising as a de novo mutation. FAB mass spectroscopic analysis is a rapid and useful analytical method for identifying aminoacid substitution.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
3/6. Managing leg ulceration in patients with sickle cell disorder.Leg ulceration is a complication associated with sickle cell disorders. Caroline Dowsett outlines why this problem occurs and describes the management of a patient with sickle cell disorder who presented with an infected leg ulcer. She concludes that there is a need for more research into the management of these complex wounds.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
4/6. A non-deletion hereditary persistence of fetal hemoglobin (HPFH) determinant not linked to the beta-globin gene complex.We describe an Asian Indian family with a non-deletion form of hereditary persistence of fetal hemoglobin (HPFH) and beta zero thalassemia. The propositus who has homozygous beta zero thalassemia has an unusually mild form of the disease which is ascribed to the co-inheritance of HPFH. The interaction of HPFH and beta thalassemia was studied in five generations of this family. Linkage analysis showed that the genetic determinant for the HPFH segregates independently from the gamma delta beta globin gene complex. Analysis of HPFH linkage to a panel of genetic markers in such a large family offers the possibility of defining a transacting locus (or loci) involved in the expression of the gamma globin gene.- - - - - - - - - - ranking = 5keywords = complex (Clic here for more details about this article) |
5/6. hemoglobinopathies: three illustrative case studies.Three cases studies from the Regional Hemoglobinopathy Laboratory at St. Joseph's Hospital in Hamilton are presented. These cases demonstrate the diagnostic value of a comprehensive hemoglobinopathy screen, family studies, and appropriate clinical information in solving complex hemoglobinopathy problems. The first case is a 79-year-old woman found to have small amounts of an unknown hemoglobin migrating electrophoretically in the position of hemoglobin S. The second case describes a boy of Greek extraction with a thalassemic blood picture but otherwise normal hemoglobinopathy screen. The third case involves a 70-year-old man with a previously normal hemoglobinopathy screen who subsequently showed evidence of alpha thalassemia.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
6/6. G gamma delta beta thalassaemia and g gamma HPFH (Hb kenya type): comparison of 2 new cases.Two new cases of G gamma delta beta thalassaemia and G gamma HPFH (Hb kenya type) have been characterised in detail and compared with regard to haematological data, globin chains biosynthesis, and intracellular distribution of Hb F. The similarities and differences between these two conditions are discussed in relation to the possible underlying defects at the molecular level and to the control of the gamma delta beta gene complex in general.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |