Evaluation of the chronic toxicity and oncogenicity of N,N-diethyl-m- toluamide (DEET)

Chronic toxicity and/or oncogenicity studies were conducted in rats, mice, and dogs with the insect repellent DEET. DEET was mixed in the diet and administered to CD rats for two years at concentrations that corresponded to dosage levels of 10, 30 or 100 mg/kg/day for males and 30, 100, or 400 mg/kg/day for females; to CD-1 mice for 18 months at dosage levels of 250, 500, or 1000 mg/kg/day; and to dogs for one year, via gelatin capsules, at dosage levels of 30, 100, or 400 mg/kg/day. In the rodent studies, each group consisted of 60 animals of each sex, and two concurrent independent control groups, each containing 60 animals/sex were included in each study. Each group in the dog study consisted of four male and four female dogs and one control group was included in the study. Treatment-related effects were observed at the highest dose level in all three studies. For rats, the effects included decreases in body weight and food consumption and an increase in serum cholesterol in females only. In mice, the effects observed were decreases in body weight and food consumption in both sexes. The effects observed in dogs included increased incidences of emesis and ptyalism, and levels of transient reduction in hemoglobin and hematocrit, increased alkaline phosphatase (males only), decreased cholesterol, and increased potassium. One male dog in the high-dose group also exhibited ataxia, tremors, abnormal head movements, and/or convulsions on several occasions during the study. The highest no- observed-effect levels (NO-ELs) for rats, mice and dogs were determined to be 100, 500, and 100 mg/kg/day, respectively. No specific target organ toxicity or oncogenicity was observed in any of the studies.      

Comparison of Four Different Carboxylterminal Tracers in a Radioimmunoassay Specific to the 68–84 Region of Human Parathyroid Hormone

Two synthetic carboxylterminal fragments, {tyr⁵²}hPTH(52–84) and {tyr⁶³}hPTH(63–84), and purified bPTH(1–84) were iodinated with ¹²⁵Iodine to be compared as tracers in a late carboxylterminal radioimmunoassay. Tracer ¹²⁵I-bPTH(41–84) was generated in vitro by incubating ¹²⁵I-bPTH(1–84) with plasma membranes of rat kidney cortex. Region specificity was achieved by saturating the unwanted middle component of our multivalent antiserum with a molar excess of hPTH(44–68). A charcoal-dextran separation was worked out for each tracer. The titer of the antiserum giving ?30% specific binding of each tracer was used in all experiments. Displacement of each tracer with increasing molar concentration of hPTH(1–84), hPTH(53–841, hPTH(41–84) and of hPTH (64–84) was studied, hPTH(41–84) was also generated by incubating hPTH(1–84) with rat cortex kidney membranes and was calibrated against a commercial preparation of bPTH(37–84). A progressive increase in the titer of the antiserum was seen as the molecular weight of the tracers decreased from a titer of 1/20,000 with ¹²⁵I-bPTH(1–84) to a titer of 1/50,000 with the two synthetic tracers. Similarly the so-called damage seen during the charcoal-dextran separation in absence of antibody was reduced from 16.0±6.2% (mean ±SD) with ¹²⁵I-bPTH(1–84) to 1.3±.2 with the two synthetic tracers. 50% displacement of the ¹²⁵I-bPTH(1–84) tracer was achieved at 13.2±.8 fmol/tube for hPTH(1–84) and at 6.3±1.0 fmol/tube for hPTH(41–84), reflecting the greater reactivity of fragments in that system. With the two synthetic tracers, a concentration of 5.0±.4 fmol/tube of hPTH(1–84) or of 3.5±1.2 fmol/tube of hPTH(41–84) was necessary to achieve the same goal. With ¹²⁵I-bPTH(41–84) results were between the two extremes. These results indicated that an increase in antiserum titer, a decrease in assay damage, an improvement in assay sensitivity and in comparative molar reactivity of the various circulating forms of hPTH can be achieved by using synthetic carboxylterminal fragments as tracers in region specific radioimmunoassays of hPTH.     

Choline kinase overexpression increases invasiveness and drug resistance of human breast cancer cells

A direct correlation exists between increased choline kinase (Chk) expression, and the resulting increase of phosphocholine levels, and histological tumor grade. To better understand the function of Chk and choline phospholipid metabolism in breast cancer we have stably overexpressed one of the two isoforms of Chk‐α known to be upregulated in malignant cells, in non‐invasive MCF‐7 human breast cancer cells. Dynamic tracking of cell invasion and cell metabolism were studied with a magnetic resonance (MR) compatible cell perfusion assay. The MR based invasion assay demonstrated that MCF‐7 cells overexpressing Chk‐α (MCF‐7‐Chk) exhibited an increase of invasion relative to control MCF‐7 cells (0.84 vs 0.3). Proton MR spectroscopy studies showed significantly higher phosphocholine and elevated triglyceride signals in Chk overexpressing clones compared to control cells. A test of drug resistance in MCF‐7‐Chk cells revealed that these cells had an increased resistance to 5‐fluorouracil and higher expression of thymidylate synthase compared to control MCF‐7 cells. To further characterize increased drug resistance in these cells, we performed rhodamine‐123 efflux studies to evaluate drug efflux pumps. MCF‐7‐Chk cells effluxed twice as much rhodamine‐123 compared to MCF‐7 cells. Chk‐α overexpression resulted in MCF‐7 human breast cancer cells acquiring an increasingly aggressive phenotype, supporting the role of Chk‐α in mediating invasion and drug resistance, and the use of phosphocholine as a biomarker of aggressive breast cancers. Copyright © 2010 John Wiley & Sons, Ltd.     

Acutely decompensated heart failure with preserved and reduced ejection fraction present with comparable haemodynamic congestion

Aims

Congestion is a central feature of acute heart failure (HF) and its assessment is important for clinical decisions (e.g. tailoring decongestive treatments). It remains uncertain whether patients with acute HF with preserved ejection fraction (HFpEF) are comparably congested as in acute HF with reduced EF (HFrEF). This study assessed congestion, right ventricular (RV) and renal dysfunction in acute HFpEF, HFrEF and non‐cardiac dyspnoea.

Methods and results

We compared echocardiographic and circulating biomarkers of congestion in 146 patients from the MEDIA‐DHF study: 101 with acute HF (38 HFpEF, 41 HFrEF, 22 HF with mid‐range ejection fraction) and 45 with non‐cardiac dyspnoea. Compared with non‐cardiac dyspnoea, patients with acute HF had larger left and right atria, higher E/e', pulmonary artery systolic pressure and inferior vena cava (IVC) diameter at rest, and lower IVC variability (all P < 0.05). Mid‐regional pro‐atrial natriuretic peptide (MR‐proANP) and soluble CD146 (sCD146), but not B‐type natriuretic peptide (BNP), correlated with echocardiographic markers of venous congestion. Despite a lower BNP level, patients with HFpEF had similar evidence of venous congestion (enlarged IVC, left and right atria), RV dysfunction (tricuspid annular plane systolic excursion), elevated MR‐proANP and sCD146, and renal impairment (estimated glomerular filtration rate; all P > 0.05) compared with HFrEF.

Conclusion

In acute conditions, HFpEF and HFrEF presented in a comparable state of venous congestion, with similarly altered RV and kidney function, despite higher BNP in HFrEF.

     

Rapid detection of vancomycin-resistant enterococci from rectal swabs by the Cepheid Xpert vanA/vanB assay

The detection of vancomycin-resistant enterococci using a novel commercial multiplex real-time polymerase chain reaction assay (Xpert™ vanA/vanB, Cepheid, Sunnyvale, CA) was evaluated on 804 rectal swab specimens. Compared to enriched culture, sensitivity and negative predictive value of this method were 100%. Many false-positive results were recovered (sensitivity, 85.4%; positive predictive value, 8.7%), especially for the vanB gene.     

Isolation of egg yolk IgY from hens immunized with S.m …

目的：从鸡蛋中提取特异性抗体,鉴定抗体性质并分析其蛋白质含量,以探索一种制备被动免疫防龋抗体的制备方法。方法变形链球菌ＧＴＦ高表达株Ｓ．ｍｕｔａｎｓＢ２９－３３及茸毛链球菌Ｓ．ｓｏｂｒｉｎｕｓ６７１５免疫母鸡,采用硫酸铵沉淀法提取鸡蛋黄抗体,ＳＤＳ－ＰＡＧＥ凝胶扫描鉴定抗体性质,分析其纯度并用分光光度法测蛋白质含量。结果：用硫酸铵沉淀法可提取出鸡蛋黄抗体,其性质为ＩｇＧ,蛋白质含量约为７．００ｍｇ