Analysis of T-cell receptor beta chain (T beta) gene rearrangements demonstrates the monoclonal nature of T-cell chronic lymphoproliferative disorders

We investigated the rearrangement patterns of the gene coding for the beta chain of the T cell receptor (T beta) in 11 patients with T-cell derived chronic lymphoproliferative disorders, including T-cell prolymphocytic leukemia (T-PLL) and T-cell chronic lymphocytic leukemia (T-CLL). We found that all five cases of T-PLL, and five of six cases of T-CLL, displayed T beta-gene rearrangements, clearly establishing their monoclonal nature. Clonality could not be determined in one case of T-CLL where the T beta gene was found unrearranged. Our results demonstrate that the majority of cases of both clinically aggressive T- PLL and clinically indolent T-CLL are monoclonal. These results suggest that the analysis of T beta gene rearrangements represents a valid tool for the differential diagnosis and clinical monitoring of T-cell derived chronic lymphoproliferative diseases.     

Poikilocytic hereditary elliptocytosis associated with spectrin Alexandria: an alpha I/50b Kd variant that is caused by a single amino acid deletion

Hereditary elliptocytosis (HE) is a heterogeneous disorder of red blood cells frequently associated with abnormal limited tryptic digestion of the alpha I domain of spectrin and impaired spectrin dimer self- association. We studied two related individuals with poikilocytic hereditary elliptocytosis (HE) of different severity. Limited tryptic digestion of spectrin from these individuals showed the presence of a variant alpha I/50b Kd peptide at the expense of the normal alpha I/80 Kd peptide. Amino acid sequence analysis of the abnormal peptide showed that the proteolytic cleavage occurred after the arginine at position 470 of the alpha spectrin chain. Spectrin from these patients had an impaired ability to undergo self-association, as evidenced by increased amounts of spectrin dimers in 4 degrees C extracts of erythrocyte membrane from affected individuals. The polymerase chain reaction was used to study the DNA sequence of the alpha spectrin gene encoding the region of the alpha spectrin chain surrounding the abnormal proteolytic cleavage site. We detected the in-frame deletion of the trinucleotide CAT, encoding histidine 469, two amino acid residues to the N-terminal side of the abnormal proteolytic cleavage site between residues 470 and 471. Similar to many other defects of spectrin associated with HE, this deletion occurs in helix three of repeat 5 of the proposed triple helical model of spectrin repeats.     

Hemophilia A: carrier detection and prenatal diagnosis by DNA analysis

In this study, we used DNA polymorphisms for carrier detection and prenatal diagnosis of hemophilia A in a large group of Italian families. The restriction fragment length polymorphisms (RFLPs) investigated were the intragenic polymorphic Bc/I site within the factor VIII gene; the extragenic multiallelic Taq I system at the St14 locus; and the extragenic Bg/II site at the DX13 locus. The factor VIII probe was informative in 30%, St14 in 82%, and DX13 in 60% of obligate carriers. The combination of factor VIII-Bc/I and St14-Taq I showed that 91% of obligate carriers were heterozygotes for one or both; with all three probes, only 4% of obligate carriers were noninformative. In families clearly segregating for hemophilia A, RFLP analysis allowed us to define the carrier status for the hemophilia A gene in all 27 women tested. RFLP analysis allowed us to exclude the carrier status in 39 of 45 female relatives of sporadic patients. The combination of RFLP analysis and biological assay of factor VIII allowed us to identify a de novo mutation in the maternal grandfather in 7 of 12 of the families with sporadic cases, for which members of three generations were available for study. Nine of 10 couples requesting prenatal diagnosis provided informative RFLP DNA pattern. Carrier status was excluded in two women, two fetuses were shown to be female, and prenatal diagnosis was carried out in five pregnancies by DNA analysis. Prenatal testing was successful in three instances and failed in two because a sufficient amount of chorionic villous DNA was not obtained for the analysis.     

Hereditary nonspherocytic hemolytic anemia and hexokinase deficiency

An 11-yr-old child with mild chronic hemolytic anemia was found to have decreased red cell hexokinase activity in spite of the reduced mean age of her red cell population. Similar decreases in red cell hexokinase activity were documented in the patient's parents and in one sib. The red cells were morphologically normal. Red cell 2,3-DPG levels were normal and ATP and glucose-6-phosphate levels were diminished. The kinetic properties, electrophoretic mobility, and thermal stability of the residual red cell hexokinase were normal or nearly so. Glucose consumption of the hexokinase-deficient cells was not appreciably decreased, probably because less of the potent inhibitor glucose-6- phosphate was present in the erythrocytes. It is likely, although not certain, that in this patient nonspherocytic hemolytic anemia resulted from hexokinase deficiency.     

Detection of homozygous deletions of the cyclin-dependent kinase 4 inhibitor (p16) gene in acute lymphoblastic leukemia and association with adverse prognostic features

A recently described putative tumor suppressor gene, the cyclin- dependent kinase 4 inhibitor (p16), has been shown to be altered by deletions and/or point mutations in various human cancers. To assess the incidence and clinico-biologic correlations of p16 homozygous deletion in hemopoietic tumors, we studied a panel of 244 DNA samples representative of distinct acute (99 cases) and chronic (57 cases) leukemia subtypes, myelodysplastic (22 cases) and myeloproliferative (15 cases) syndromes, and lymphomas (51 cases). A 361-bp probe complementary to the p16 exon 2 gene sequences was generated by polymerase chain reaction and used in Southern blot hybridization against these tumor DNAs. Homozygous deletions of p16 (p16-/-) were detected in 10 of 58 (17%) cases of acute lymphoblastic leukemia (ALL) of either B or T lineage and in no other tumors. Single-strand conformation polymorphism analysis of p16 exons 1 and 2 was also performed in 40 of the 58 ALL cases and in 16 lymphomas. In no cases were point mutations detected. The comparison of clinical features at presentation in p16-/- and in p16 germline ALL cases showed a greater leukemic cell mass (P = .001) and higher white blood cell counts (P = .01) in the former group. Two ALL cases in which diagnostic and relapse DNA samples were available showed p16-/- in both specimens. We conclude that homozygous p16 gene deletions characterize a subset of ALL with features of aggressive disease.     

Role of transforming growth factor beta in peritoneal fibrosis

SUMMARY: Technique survival of peritoneal dialysis is seriously limited by the development of peritoneal fibrosis. the mesothelial cell layer lining the peritoneum is important in the pathogenesis of peritoneal fibrosis. Mesothelial cells are able to produce transforming growth factor beta (TGF-β), and respond to stimulation by this cytokine. In this review, we will detail the evidence available so far for the role of the complex interaction between TGF-β and mesothelial cells in the development of peritoneal fibrosis.     

Effect of methemoglobin formation on the MR appearance of subarachnoid hemorrhage

Subarachnoid hemorrhage has a much higher intensity in magnetic resonance (MR) images with the passage of time. Acute subarachnoid hemorrhage is difficult to see; within 1 week its appearance has become intensified on T1-weighted images. Different concentrations of blood and lysed red blood cells in cerebrospinal fluid (CSF) were examined spectroscopically but did not significantly alter T1 and T2 relaxation of CSF acutely. Ultraviolet visible spectroscopy of bloody CSF stored hypoxically for 3 days showed the presence of methemoglobin. The iron in methemoglobin is paramagnetic; in combination with water this facilitates T1 relaxation. It is concluded that methemoglobin formation with T1 shortening at least partially accounts for the increasing intensity of the MR appearance of subarachnoid hemorrhage over time in the central nervous system and may also explain the intense appearance of subacute hemorrhage in MR images elsewhere in the body.     

朝藿素D的分离和结构

从朝鲜淫羊藿(Epimedium koreanum)地上部分分离得到一新黄酮成分(I)和一已知化合物(II)。经光谱解析,证明I的结构为5,7,3',4'-tetrahydroxy-5'-prenylflavone,命名为朝藿素D(epimedokoreanin D);II为2-hydroxy-3,4,6,7-tetramethoxy-9,10-dihydrophenanthren。