Enterotoxicity and cytotoxicity of Vibrio parahaemolyticus thermostable direct hemolysin in in vitro systems

Vibrio parahaemolyticus is a marine bacterium known to be a common cause of seafood gastroenteritis worldwide. The thermostable direct hemolysin (TDH) has been proposed to be a major virulence factor of V. parahaemolyticus. TDH causes intestinal fluid secretion as well as cytotoxicity in a variety of cell types. In this study, we investigated the interplay between the hemolysin's enterotoxic and cytotoxic effects by using both human and rat cell monolayers. As revealed by microspectrofluorimetry, the toxin causes a dose-dependent increase in intracellular free calcium in both Caco-2 and IEC-6 cells. This effect was reversible only when low toxin concentrations were tested. The TDH-activated ion influx pathway is not selective for calcium but admits ions such sodium and manganese as well. Furthermore, in the same range of concentration, the hemolysin triggers a calcium-dependent chloride secretion. At high concentrations, TDH induces a dose-dependent but calcium-independent cell death as assessed by functional, biochemical, and morphological assays.     

Evolution of emphysema in relation to smoking

Purpose  

We have little knowledge about the evolution of emphysema, and relatively little is understood about its evolution in relation to smoking habits. This study aims to assess the evolution of emphysema in asymptomatic current and former smokers over 2 years and to investigate the association with subjects’ characteristics. The study was approved by our Ethics Committee and all participants provided written informed consent.     

Improved outcome for children with acute lymphoblastic leukemia: results of Total Therapy Study XIIIB at St Jude Children's Research Hospital

St Jude Total Therapy Study XIIIB for childhood acute lymphoblastic leukemia (ALL) incorporated more stringent risk classification, early intensification of intrathecal chemotherapy, reinduction treatment, and the addition of dexamethasone to postremission therapy to increase the proportion of event-free survivors without jeopardizing their quality of life. Cranial irradiation was reserved for the 12% of patients who had T-cell ALL and a presenting leukocyte count of 100 x 10(9)/L or more, or CNS-3 (5 or more leukocytes/microL with identifiable blast cells in an atraumatic sample or the presence of cranial nerve palsy) status. Among the 247 consecutive patients enrolled in the study, 117 were classified as having lower-risk leukemia and received mainly antimetabolite-based continuation therapy; the 130 cases with higher-risk leukemia received more intensive continuation chemotherapy with multiple drug pairs administered in weekly rotation. The 5-year event-free survival estimate was 80.8% +/- 2.6% (SE); the 8-year rate was 78.6% +/- 5.8%. The 5-year cumulative risk of an isolated central nervous system (CNS) relapse was 1.7% +/- 0.8%, and that of isolated plus combined CNS relapse was 3.0% +/- 1.1%. The 5-year cumulative risks of etoposide-related myeloid malignancies were 1.8% +/- 1.3% in the lower-risk patients who received a cumulative dose of 1.2 g/m(2) and 5.0% +/- 2.0% in the higher-risk patients who received a cumulative dose of up to 14.4 g/m(2) (P = .18). Independent adverse prognostic features included the presence of MLL-AF4 or BCR-ABL fusion gene and minimal residual leukemia of 0.01% or more at the end of the 6-week remission induction phase. Our results suggest the efficacy of early intensification of intrathecal chemotherapy and provide the basis for studies omitting cranial irradiation altogether.     

Clinical presentation, karyotypic characterization, and treatment outcome of childhood acute lymphoblastic leukemia with a near-haploid or hypodiploid less than 45 line

Cytogenetic and DNA flow cytometric analyses of leukemic cells from 2,184 children with newly diagnosed acute lymphoblastic leukemia (ALL) identified 27 cases (1.2%) that had a hypodiploid line with fewer than 45 chromosomes per cell. Had cytogenetic techniques been used alone, seven cases would have been missed, compared with five if only flow cytometry had been used. For comparative purposes, the 27 cases were divided into three groups: near-haploid (n = 10), hypodiploid 30-40 (n = 9), and hypodiploid 41-44 (n = 8). Blast cells from patients with near-haploid ALL lacked structural chromosomal abnormalities; showed nonrandom retention of two copies of chromosomes 8, 10, 14, 18, 21, and the sex chromosomes; and had a second leukemic line with exactly twice the number of chromosomes or DNA content. Karyotypic analysis of the hypodiploid 30-40 and hypodiploid 41-44 groups disclosed structural abnormalities in the stemline or sideline of most of the well-banded cases; those in the latter group were similar to findings in cases with 45 chromosomes. As in the near-haploid group, chromosome 21 and the sex chromosomes were preferentially retained in the hypodiploid 30-40 and 41-44 cases. Except for a slight excess of female patients in the near-haploid group and an older age at diagnosis in the hypodiploid 30-40 cases, there were no initial clinical features that distinguished these patients from the general ALL population. Despite intensive treatment and short follow-up, 17 of the 27 patients have relapsed. This study suggests that the poor treatment responsiveness of hypodiploid ALL is not limited to the more than 80% of the patients who have 45 chromosomes per leukemic cell and demonstrates that cytogenetic and flow cytometric analyses are complementary in the evaluation of children with ALL.     

Isochromosomes in childhood acute lymphoblastic leukemia: a collaborative study of 83 cases.

Cytogenetic analysis of leukemic cells from 2,805 children with newly diagnosed acute lymphoblastic leukemia (ALL) identified 83 cases (3%) that had a stemline with at least one isochromosome. The i(9q) was present in 28 (1%), the i(17q) in 23 (0.8%), and the i(7q) in 23 (0.8%). Other isochromosomes--i(21q), i(6p), i(1q), i(8q), or i(Xq)--were found in only 12 cases (0.4%). The isochromosome cases were more likely than were other ALL cases to have a pre-B immunophenotype (38% v 25%, P = .02) and leukemic cell hyperdiploidy greater than 50 (37% v 24%, P = .02); five cases had both features. The i(9q) was associated with age greater than 10 years (P less than .05) and the pre-B immunophenotype (P = .05); both the i(17q) and i(7q) had high frequencies of hyperdiploidy greater than 50 (P less than .0001 and P = .05, respectively). The t(1;19)(q23;p13) was a common feature (23%) in cases with the i(9q), i(7q), i(6p), or i(1q). These findings establish the i(9q), i(17q), and i(7q) as nonrandom chromosomal abnormalities in ALL. The prognostic significance of the presence of isochromosome(s) remains to be determined.