Serum esterase inhibition in birds: A nondestructive biomarker to assess organophosphorus and carbamate contamination

With the aim of proposing a nondestructive biomarker for monitoring the toxicological risk to birds of exposure to the organophosphorus insecticide azamethiphos and the carbamate insecticide methomyl, laboratory studies were performed on serum B esterases in Japanese quail (Coturnix coturnix japonica). The birds received two single dose treatments of each compound (azamethiphos and methomyl), i.e., 50 mg/kg and 250 mg/kg respectively. In the first treatment, serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) were drastically inhibited in the azamethiphos-treated group, 24 h after the dose. No inhibition was detected for BChE and CbE activities in the methomyl-treated group, 24 h after the dose. In the second treatment, the birds died or were sacrified 3 h after the dose. Serum BChE and brain acetylcholinesterase (AChE) were strongly inhibited after treatment with both insecticides. Serum CbE, hepatic microsomal CbE and 7-ethoxyresorufin dealkylation activities were also inhibited. A statistically significant correlation between serum BChE and brain AChE was found at lethal and sublethal doses of these xenobiotics. The experimental results indicate that the nondestructive biomarker BChE can give an early qualitative and semi-quantitative warning of the toxic effects of organophosphate and carbamate insecticides in birds.     

Common gene polymorphisms in the metabolic folate and methylation pathway and the risk of acute lymphoblastic leukemia and non-Hodgkin's lymphoma in adults.

Folate and methionine metabolism is involved in DNA synthesis and methylation processes. Polymorphisms in the genes of folate metabolism enzymes have been associated with some forms of cancer. In a case-control study, we evaluated whether four common polymorphisms in methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), methionine synthase (MS A2756G), and methionine synthase reductase (MTRR A66G) genes may have a role in altering susceptibility to adult acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). We analyzed DNA of 120 adult ALL, 200 NHL, and 257 healthy control subjects. Individual carrying the MTHFR 677TT genotype showed a 3.6-fold decreased ALL risk [odds ratio (OR) 0.28, 95% confidence interval (95% CI) 0.12-0.72] than wild-types. Similarly, MS 2756GG individuals showed a 5.0-fold decreased ALL risk (OR 0.20, 95% CI 0.02-1.45) than wild-types. In combined results, subjects with the MTHFR 677CT/TT and MS 2756AG/GG genotypes revealed a 3.6-fold ALL risk reduction (OR 0.28, 95% CI 0.14-0.58) and those with the MTHFR 677TT and MTRR 66AG genotypes revealed a 4.2-fold ALL risk reduction (OR 0.24, 95% CI 0.06-0.81). Finally, those with the MS 2756AG/GG and MTRR 66AG/GG genotypes revealed a 2.2-fold ALL risk reduction (OR 0.45, 95% CI 0.10-0.85). Single analysis for NHL did not show any significant difference for all the polymorphisms investigated, but in the low-grade NHL subgroup, we found a 2.0-fold risk reduction for the MTRR 66GG homozygous genotype (OR 0.50, 95% CI 0.25-0.99), which was higher (OR 0.37, 95% CI 0.14-0.85) when analyzed in combination with MS 2756AA genotype. These data are in accordance with the hypothesis that polymorphisms in the genes for folate and methionine metabolism might play a greater role in the occurrence of ALL than NHL by influencing DNA synthesis and/or DNA methylation.     

Expression of the ELAV-like protein HuR is associated with higher tumor grade and increased cyclooxygenase-2 expression in human breast carcinoma.

PURPOSE: The human ELAV (embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellular mRNAs that contain AU-rich elements in their 3'-untranslated region. Cell culture studies have shown that the mRNA of cyclooxygenase (COX)-2 can be stabilized by HuR. EXPERIMENTAL DESIGN: To investigate a possible contribution of dysregulation of mRNA stability to the progression of cancer and to overexpression of COX-2, we studied expression of HuR in 208 primary breast carcinomas by immunohistochemistry. RESULTS: There were two different staining patterns of HuR in tumor tissue of breast carcinomas: nuclear expression was seen in 61% of cases; and an additional cytoplasmic expression was seen in 30% of cases. Expression of HuR was significantly associated with increased COX-2 expression; this association was particularly significant for cytoplasmic HuR expression (P < 0.0005). We further observed a significant association of cytoplasmic (P = 0.002) or nuclear HuR (P = 0.027) expression with increased tumor grade. Only 13% of the grade 1 carcinomas showed cytoplasmic expression of HuR, compared with 46% of the grade 3 carcinomas. There was no significant correlation between HuR expression and other clinicopathological parameters such as histological type, tumor size, or nodal status as well as patient survival. CONCLUSIONS: Our results suggest that overexpression of HuR in tumor tissue may be part of a regulatory pathway that controls the mRNA stability of several important targets in tumor biology, such as COX-2. Based on our results, additional studies are necessary to investigate whether HuR might be a potential target for molecular tumor therapy.     

P7 antigen expression in human breast cancer.

PURPOSE: Evaluate p7 expression in human breast cancer and determine whether chemotherapy and radiation therapy effect a change in p7 expression. EXPERIMENTAL DESIGN: Using a p7-specific monoclonal antibody with immunohistochemistry and Western immunoblot analyses to assess p7 expression in archival, frozen breast cancer specimens both before and after therapy. RESULTS: A novel 7 kDa protein (p7), originally identified in multidrug-resistant ovarian and breast cancer cell lines, was found to be expressed in 21 of 64 (32%) primary, unselected human breast cancer specimens by immunohistochemistry with the use of a p7-specific monoclonal antibody, 1D7. P7 was observed in malignant cells but not in other types of cells in the breast tissue. Western blot analysis confirmed the 7 kDa polypeptide in p7-positive breast carcinomas identified by immunohistochemistry. P7 expression was significantly associated with breast cancers having distant metastasis and/or local recurrence (P = 0.027, Fisher's exact test). In addition, p7 expression was significantly increased in post-treatment breast cancer biopsy specimens compared with pretreatment breast cancer biopsy specimens in patients with locally advanced breast cancer after 5-fluorouracil chemotherapy and radiation therapy [2 of 15 (13%) pretreatment breast cancers compared with 8 of 15 (53%) post-treatment breast cancers; P = 0.016, McNemar's test]. CONCLUSIONS: These findings demonstrate that expression of p7 is associated with malignant tumor cells in primary breast cancers, especially those showing recurrent or metastatic disease. Its specific association with the malignant phenotype suggests it may have potential for novel target-based therapies. The markedly increased expression in patients with locally advanced disease after neoadjuvant therapy suggests a role for p7 in treatment outcome.     

p15INK4b, p14ARF, and p16INK4a inactivation in sporadic and neurofibromatosis type 1-related malignant peripheral nerve sheath tumors.

PURPOSE: Malignant peripheral nerve sheath tumor (MPNST) can arise sporadically or in association with neurofibromatosis type 1. Deletions at the 9p21 locus have been reported in these tumors. To additionally characterize the status of this chromosomal region, in this study we performed a comprehensive, mostly PCR-based molecular analysis of the three tumor suppressor genes p15(INK4b), p14(ARF) and p16(INK4a) located at the 9p21 locus in 26 cryopreserved MPNSTs. EXPERIMENTAL DESIGN: Fourteen neurofibromatosis type 1-related and 12 sporadic cases were investigated for homozygous deletion coupled with fluorescent in situ hybridization, promoter methylation, and mutational analysis, as well as m-RNA expression. RESULTS: The results showed that an inactivation of one or more genes occurred in 77% of MPNSTs and was mainly achieved through homozygous deletion (46%), which, in turn, encompassed all of the three tandemly linked genes in 83% of the deleted cases. Promoter methylation was at a less extent involved in gene silencing (18%), and no mutations were found. Loss of function at DNA level strongly correlated with loss of mRNA expression accounting for 80% of the cases. Because of the close relationship between p14(ARF) and TP53 and between p15(INK4b)/p16(INK4a) and Rb, these results support a model of a coinactivation of TP53 and Rb pathways in 75% of MPNSTs, with functional consequences on cell growth control and apoptosis. CONCLUSIONS: The inactivation of the 9p21 locus is a frequent and peculiar hallmark of MPNST genetic profile leading also to an impaired apoptosis that could be taken into account in treatment planning of these tumors.     

Alpha1 acid glycoprotein binds to imatinib (STI571) and substantially alters its pharmacokinetics in chronic myeloid leukemia patients.

PURPOSE: Imatinib (Glivec) is a potent inhibitor of bcr/abl, an oncogenic fusion protein that causes chronic myelogenous leukemia (CML). alpha1 acid glycoprotein (AGP) binds to imatinib with high affinity and inhibits imatinib activity in vitro and in vivo in an animal model. A pharmacokinetics analysis of imatinib was undertaken in CML patients. EXPERIMENTAL DESIGN: Imatinib plasma concentrations were measured in 19 CML patients treated with imatinib (400 or 600 mg/day). Five patients received a concomitant short-term course of clindamycin (CLI). RESULTS: A positive correlation between AGP and imatinib plasma levels was observed. CLI administration decreased imatinib plasma concentrations, evaluated as area under the curve (AUC) and peak concentrations (C(max)). The effects of a bolus of CLI was studied in three patients on imatinib 23 h after the last imatinib dose. Within 5-10 min in three of three cases, CLI caused a decrease in imatinib plasma concentrations of 2.6-, 2.7-, and 4.7-fold, respectively. In vitro experiments using fresh blasts from CML patients showed that AGP, at concentrations observed in the patients, decreased imatinib intracellular concentrations up to 10 times and blocked imatinib activity. The incubation with CLI restored imatinib intracellular concentrations and biological activity. CONCLUSION: AGP exerts significant effects of the pharmacokinetics, plasma concentrations, and intracellular distribution of imatinib in CML patients; these data indicate that plasma imatinib levels represent unreliable indicators of the cellular concentrations of this molecule.     

Morphology, toxin composition and pigment content of Prorocentrum lima strains isolated from a coastal lagoon in southern UK.

Prorocentrum lima was isolated from the coastal Fleet lagoon, Dorset, UK in 2000 and a number of clonal cultures established. These were analyzed for okadaic acid (OA), dinophysistoxin-1 (DTX-1), DTX-2, DTX-4 and diol esters by liquid chromatography coupled to mass spectrometry. OA concentrations varied from 0.4 to 17.1pg OAcell(-1) and DTX-1 from 0.4 to 11.3pg DTX-1cell(-1); DTX-2 was not detected in these isolates. OA and DTX-1 were detected in the culture media, as a result of toxin excretion. DTX-4 and a selection of DTX-4 diol esters were identified using selected ion monitoring, although not all strains produced these compounds. Cell size and number of marginal and valve pores of each strain were observed using scanning electron microscopy. OA and DTX-1 concentrations, pigment content and changes in nitrate and phosphate concentrations in the culture media were followed during growth of one strain of P. lima in batch culture. Diarrhetic shellfish poisoning (DSP) toxins have been previously detected in shellfish cultivated in the Fleet lagoon, but in the absence of any Dinophysis sp. cells. The identification of toxic P. lima strains from the Fleet suggests that this dinoflagellate is the most probable source of occasional DSP detected in the lagoon.     

A comparative study of the utility of two superdisintegrants in microcrystalline cellulose pellets prepared by extrusion-spheronization.

This study evaluated the utility of including superdisintegrants (croscarmellose sodium or sodium starch glycolate) in microcrystalline cellulose extrusion-spheronization pellets as a means of increasing the dissolution rate of poorly water-soluble drugs. The model drug was hydrochlorothiazide, with water or water/ethanol as wetting agent for pellet preparation. Neither disintegrant had significant effects on pellet morphology, flow properties or mechanical resistance. Neither disintegrant caused disintegration of the pellet in drug dissolution medium. Nevertheless, the disintegrants afforded a modest increase in drug dissolution rate, attributable to the observed increase in pellet micropore volume. Drug dissolution rate was slightly higher in pellets prepared with sodium starch glycolate, probably because of this disintegrant's higher swelling capacity.     

Prevention of central venous catheter-related bloodstream infections using non-technologic strategies.

OBJECTIVE: To evaluate the incidence of nosocomial bacteremias related to the use of non-impregnated central venous catheters (CVCs) when only non-technologic strategies were used to prevent them. DESIGN: This was a prospective study of infectious complications of CVCs placed in intensive care unit (ICU) patients from April 1997 to December 2001. SETTING: The medical-surgical ICU of a tertiary-care, university-affiliated hospital in Argentina. METHODS: We studied all patients admitted to the ICU using non-impregnated CVCs. Maximal sterile barrier precautions (ie, use of cap, mask, sterile gown, sterile gloves, and large sterile drape), strict handwashing, preparation of the patients' skin with antiseptic solutions, insertion and management of catheters by trained personnel, and continuing quality improvement programs aimed at appropriate insertion and maintenance of catheters were employed. RESULTS: During the study period, 2,525 patients were admitted to the ICU. Eight hundred sixty-eight patients had 1,037 CVCs inserted. The number of CVC-related bloodstream infections (BSIs), acquired in the ICU, was 2.7 per 1,000 CVC-days (13 nosocomial CVC-related BSIs during 4,770 days of CVC use). Microorganisms isolated included methicillin-susceptible Staphylococcus aureus (n = 6), methicillin-resistant S. aureus (n = 2), coagulase-negative methicillin-resistant Staphylococcus (n = 2), Escherichia coli (n = 1), Klebsiella pneumoniae (n = 1), and Enterobacter cloacae (n = 1). CONCLUSIONS: A low rate of catheter-related BSI was achieved without antimicrobial-impregnated catheters. The incidence of CVC-associated bacteremias corresponded to the 10th to 20th percentile range of the National Nosocomial Infections Surveillance System hospitals for the same type of ICU.