Monocytoid differentiation of freshly isolated human myeloid leukemia cells and HL-60 cells induced by the glutamine antagonist acivicin

Previously we showed that starvation of HL-60 promyelocytic leukemia cells for a single essential amino acid induced irreversible differentiation into more mature monocyte-like cells. Although not an essential amino acid, glutamine is important in the growth of normal and neoplastic cells. The glutamine analogue, alpha S,5S-alpha-amino-3- chloro-4,5-dihydro-5-isoxazoleacetic acid (acivicin) inhibits several glutamine-utilizing enzymes and therefore depletes cells of certain metabolic end products. The current study was designed to examine in vitro the effects of acivicin on growth and differentiation of several established human myeloid leukemia cell lines, including the HL-60 cell line, and of freshly isolated cells from patients with acute nonlymphocytic leukemia (ANLL). Four-day culture of HL-60 cells with acivicin at concentrations of 0.1 to 10.0 micrograms/mL (0.56 to 56 nmol/L) decreased cell growth by 33% to 88% as compared with untreated control cells. Viability of cells was greater than 92% for untreated cells and 93% to 41% for acivicin-treated cells. Cells treated with acivicin differentiated along a monocytic pathway as shown by increased H2O2 production and alpha-naphthyl butyrate esterase (NSE) content. Differentiation was time and dose dependent, and was irreversible. Changes in H2O2 production and NSE content were partially abrogated by co-culture with 10 mmol/L exogenous cytidine and guanosine but not by co-culture with other nucleosides or glutamine. At these concentrations of acivicin, differentiation was associated with expression of the N- formyl-methyl-leucyl-phenylalanine-receptor (FMLP-R) on 8% to 29% of cells as compared with 8% for control cells. Acivicin potentiated the differentiating effects of interferon-gamma, tumor necrosis factor, dihydroxyvitamin D3, dimethylsulfoxide, and retinoic acid. Culture of cells from the U937 (monoblastic), K562 (erythroleukemia), and KG-1 (myeloblastic) cell lines resulted in decreased growth and viability, but not consistently in differentiation. Acivicin decreased survival of freshly isolated ANLL cells and increased their H2O2 production and NSE content. These results suggest that the glutamine analogue acivicin may be useful as a differentiating agent with antileukemia activity in patients with ANLL.     

Influence of exercise training frequency on cardiac and hepatic oxidative stress in rats

The present study investigated the influence of different frequencies of moderate exercise (13 weeks of treadmill running at 60% of maximal oxygen consumption) on oxidative stress in the heart and liver in rats. Oxidative stress was evaluated by chemiluminescence and lipid peroxidation (LPO) through thiobarbituric acid reactive substances. Activities of superoxide dismutase (SOD), glutathione peroxidase (GHPx) and catalase (CAT) were also measured. The animals were divided into four groups: control (C), acute ([A], only one exercise session at the end of 13 weeks), low frequency ([LF], one session a week for 13 weeks) and high frequency ([HF], five sessions a week for 13 weeks). Chronic exercise promoted cardiac hypertrophy in the HF group. Myocardial LPO in groups A and LF was increased, whereas in the HF group, it was decreased when compared with group C. The HF group demonstrated decreased myocardial SOD and GHPx activities and increased CAT activity. All exercise groups exhibited an increase in LPO in the liver compared with group C. SOD activity in liver was lower in the HF group and higher in the LF group as compared with group C. GHPx activity was higher in group A in relation to group C. Hepatic CAT activity was higher in groups A, LF and HF. It is suggested that chronic exercise training at a submaximal level is better than infrequent exercise bursts to promote metabolic adaptations that minimize oxidative stress.     

Prevention of acquired transient defect in platelet plug formation by infused prostacyclin

Cardiopulmonary bypass in baboons produced transient severe platelet dysfunction (bleeding times prolonged to 27.8 +/- 1.4 min compared with 3.9 +/- 0.7 baseline) that was associated with a parallel release of platelet alpha-granule proteins into plasma (platelet factor 4 and beta- thromboglobulin levels of 28.8 +/- 9.3 and 20.0 +/- 1.8 ng/ml, respectively) and their clearance into urine with a reciprocal depletion from circulating platelets. In contrast, platelet-dense granules did not undergo significant release. The bleeding times normalized rapidly following bypass (8.5 +/- 1.4 min at 1 hr). The infusion of prostacyclin (PGI2) into the bubble oxygenator during bypass (40--80 ng/kg/min) prevented the prolongation in bleeding time (p less than 0.01 compared with untreated control values) but did not block the release of alpha-granule proteins. Dosages outside this range were associated with prolonged bleeding times. These results show that transient platelet dysfunction occurring during cardiopulmonary bypass represents activation of platelets independent of alpha or dense granule release and is blocked by potent short-acting inhibition of platelet function using PGI2 infused into the oxygenator apparatus at optimal therapeutic doses.     

A typical case of myoclonic epilepsy with ragged red fibers (MERRF) and the lessons learned

Mitochondrial diseases have a special predilection to involve the brain in view of its high metabolic demand and the tendency for the formation of excitatory neurotransmitters when there is deficiency of intracellular ATP. These diseases have a great phenotypic variation and need a high degree of suspicion. However, some specific syndromes are well defined, both genotypically and phenotypically. Some of the drugs are potentially fatal mitochondrial poisons and an insight into that may be lifesaving as well as prevent serious morbidities. We report a typical case of myoclonic epilepsy with ragged red fibers (MERRF) with classical phenotype and genotype. There was rapid multiaxial deterioration with the introduction of sodium valproate which partly reversed on introducing mitochondrial cocktail and withdrawal of the offending drug. Sodium valproate, phenobarbitone, chloramphenicol and many anti-viral agents are mitochondrial poisons that increase the morbidity and mortality in patients with mitochondrial disease. More harm to the patient can be avoided with insight into this information.KEY WORDS: Midline lipoma, mitochondrial disease, sodium valproate     

Targeting of interleukin-13 receptor on human renal cell carcinoma cells by a recombinant chimeric protein composed of interleukin-13 and a truncated form of Pseudomonas exotoxin A (PE38QQR)

We have previously shown that human renal cell carcinoma (RCC) cells express large numbers of interleukin-13 receptors (IL-13R), a newly described hemopoietic growth factor receptor. To target tumor cells that express IL-13R, we have produced a chimeric protein composed of human IL-13 and a derivative of Pseudomonas exotoxin A, termed PE38QQR. We report here that IL13-PE38QQR is highly cytotoxic to many human RCC cell lines. IL-13R-negative cell lines or cell lines expressing low numbers of IL-13R ( < 300 sites/cell) that include human bone marrow- derived cells were not susceptible to the cytotoxic effect of IL 13- PE38QQR. The sensitivity of RCC cells to IL13-PE38QQR correlated positively with the density of IL-13R. The cytotoxic activity of IL13- PE38QQR was competed by an excess of IL-13 in a protein synthesis inhibition assay and confirmed by a clonogenic assay. Even though IL-13 and IL-4 are homologues and IL-4R and IL-13R have been proposed to share a receptor subunit, IL-4 did not compete for the cytotoxicity mediated by IL13-toxin on RCC. IL13-PE38QQR competes for [125I]-IL-13 binding sites on RCC cells, although at a lower affinity than the wild- type recombinant cytokine. Human T-cell, B-cell, and monocytic cell lines are unresponsive to the cytotoxic action of IL13-PE38QQR. Thus, our results indicate that IL13-PE38QQR is highly cytotoxic to human RCC cells, although it is not cytotoxic to a variety of normal hematopoietic cells. IL13-PE38QQR should be further investigated preclinically for the treatment of human RCCs.     

Analysis of antibodies against components of the autonomic nervous system in diabetes mellitus

Antibodies to autonomic nervous system structures have previously been detected using a complement fixation immunofluorescence test in the sera of patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM). These antibodies might play a role in the aetiology of autonomic neuropathy. Sera from 45 IDDM, 40 NIDDM and 52 control subjects were tested by immunofluorescence for antibodies to human sympathetic ganglia, human adrenal medulla and rabbit vagus nerve. The use of human sympathetic ganglia was compared with rabbit tissue for the detection of sympathetic ganglia antibodies; the results for these autonomic nervous system antibodies were also compared with results using an ELISA. There was no relationship between the presence of antibodies detected by ELISA and those detected by immunofluorescence, but of 14 IDDM patients with thyroid antibodies, 12 had autonomic nervous system antibodies detected by either immunofluorescence or ELISA (p < 0.005 compared to patients without thyroid antibodies). To further characterize the autoantigen(s), immunoblotting was performed. An adrenal antigen corresponding to 74 kDa was detected in sera from three patients, only one of whom had antibodies detectable by ELISA and immunofluorescence. One IDDM serum showed specific binding to a vagus nerve antigen corresponding to 33 kDa. No specific binding to sympathetic ganglia antigen was demonstrated. Antibodies against autonomic nervous system antigens are an inconsistent feature of diabetes, and appear more associated with coincidental autoimmunity against other organs such as the thyroid.      

Immunologic events during the incubation period of hepatitis C virus infection: the role of antibodies to E2 glycoprotein. Multicentre Hemodialysis Cohort Study on Viral Hepatitis

BACKGROUND: The study of the sensitivity of screening assays is greatly facilitated by testing the sequential changes in seroconverting individuals. The aim of this study was to investigate the early immunologic response after hepatitis C virus (HCV) infection and to evaluate whether HCV envelope (E2) recombinant antigen would provide a significant increase in sensitivity for detection of anti-HCV. STUDY DESIGN AND METHODS: Twenty hemodialysis patients who were seroconverting to anti-HCV were included in this study. They were followed up for a mean period (+/− SD) of 10.5 +/− 3.3 months, in which 13 to 46 serum samples per case were collected. Each sample was tested for anti-HCV by second- and third-generation enzyme immunoassay (EIA-2 and EIA-3) and recombinant immunoblot assay (RIBA-3). E2 antibodies were tested by a prototype EIA in which E2 was expressed as a recombinant antigen in Chinese hamster ovary cells. RESULTS: Alanine aminotransferase elevation was observed in 18 of 20 cases. Reactivity against c100, c33c, c22, NS5, and E2 was detected in 15 (75%), 19 (95%), 15 (75%), 2 (10%), and 17 (85%) patients, respectively; c33c was the most immunogenic antigen, followed in descending order by E2, c22, c100, and NS5. E2 antibody reactivity resolved the two RIBA-3- indeterminate cases. However, there was no case in which E2 reactivity preceded all other HCV antigens. Anti-E2 was found to react in all patients of genotypes 1a, 1b, and 3a but in only 2 of 4 patients of genotype 4a. CONCLUSION: In this group of seroconverting individuals, E2 antigen was shown to be highly immunoreactive and did resolve some RIBA-3-indeterminate samples as being positive, on the basis of reactivity to multiple antigens, but it did not improve early detection of seroconversion.     

The impact of the time to start radiation therapy on overall survival in newly diagnosed glioblastoma

Journal of Neuro-Oncology - We sought to determine which therapeutically targetable immune checkpoints, costimulatory signals, and other tumor microenvironment (TME) factors are independently...     

Hyper-dominant left anterior descending coronary artery with continuation as a posterior descending artery—An extended empire

Hyper-dominant left anterior descending artery (LAD) is a rare coronary anomaly where LAD continues as a posterior descending artery. It is a rare coronary anomaly and there are only 19 cases reported so far in 17 case reports in the literature. Its involvement during acute coronary syndrome can be fatal as it leads to ischemia/infarction of a larger area of left and/or right ventricular myocardium. Its early recognition and management is essential with a high index of clinical suspicion.     

高效液相色谱法同时测定盐酸维拉帕米及其主要代谢产物

建立了反相高效液相色谱法同时测定人血浆中维拉帕米及其主要代谢产物去甲维拉帕米血药浓度.以甲醇—水—三乙胺(67∶33∶0.4,pH6.7)为流动相,乙吗噻嗪(ethmosine)为内标,样品用正己烷—正丁醇混合液提取浓缩后进样,紫外检测器检测(279nm)。此法操作简便,精密度好,日内、日间误差:维拉帕米<8.6%,去甲维拉帕米<7.6%;方法回收率高,维拉帕米、去甲维拉帕米回收率均>92%。两者血药浓度在25～1000ng·ml-1范围内呈线性关系,最小检测浓度维拉帕米:2.5ng·ml^-1,去甲维拉帕米:5.0ng·ml^-1。应用该法测定了6名志愿者口服盐酸维拉帕米片剂后的血药浓度。