Induction of sister chromatid exchanges by cypermethrin and carbosulfan in bone marrow cells of mice in vivo

The public health effects of pesticides cannot be denied. However, the undesired effects of chemical pesticides have been recognized as a serious public health concern during the past decades. The present study describes the genotoxic effects of two pesticides, namely cypermethrin and carbosulfan, in a murine test system in vivo. The test parameter used was analysis of sister chromatid exchanges (SCE) in bone marrow cells. Both cypermethrin (5, 10 and 20 mg/kg) and carbosulfan (1.25, 2.5 and 5 mg/kg) induced significant increases in the frequency of SCEs (P < 0.001). However, no significant dose-response correlation could be found for either of the pesticides. Carbosulfan induced a cell cycle delay, as evidenced by an increase in average generation time accompanied by accumulation of cells in the first division cycle, but cypermethrin did not induce any such response. The present study indicates that carbosulfan has a higher potential to cause genetic alterations than cypermethrin in mice and may also pose a mutagenic risk to human beings.     

Novel Mutations in Cyclin-Dependent Kinase-Like 5 (CDKL5) Gene in Indian Cases of Rett Syndrome

Rett syndrome is a severe neurodevelopmental disorder, almost exclusively affecting females and characterized by a wide spectrum of clinical manifestations. Both the classic and atypical forms of Rett syndrome are primarily due to mutations in the methyl-CpG-binding protein 2 (MECP2) gene. Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been identified in patients with atypical Rett syndrome, X-linked infantile spasms sharing common features of generally early-onset seizures and mental retardation. CDKL5 is known as serine/threonine protein kinase 9 (STK9) and is mapped to the Xp22 region. It has a conserved serine/threonine kinase domain within its amino terminus and a large C-terminal region. Disease-causing mutations are distributed in both the amino terminal domain and in the large C-terminal domain. We have screened the CDKL5 gene in 44 patients with atypical Rett syndrome who had tested negative for MECP2 gene mutations and have identified 6 sequence variants, out of which three were novel and three known mutations. Two of these novel mutations p.V966I and p.A1011V were missense and p.H589H a silent mutation. Other known mutations identified were p.V999M, p.Q791P and p.T734A. Sequence homology for all the mutations revealed that the two mutations (p.Q791P and p.T734A) were conserved across species. This indicated the importance of these residues in structure and function of the protein. The damaging effects of these mutations were analysed in silico using PolyPhen-2 online software. The PolyPhen-2 scores of p.Q791P and p.T734A were 0.998 and 0.48, revealing that these mutations could be deleterious and might have potential functional effect. All other mutations had a low score suggesting that they might not alter the activity of CDKL5. We have also analysed the position of the mutations in the CDKL5 protein and found that all the mutations were present in the C-terminal domain of the protein. The C-terminal domain is required for cellular localization through protein–protein interaction; any mutations in this domain might alter this function of the protein. This is the first report from India showing the mutation in CDKL5 gene in Indian cases of Rett syndrome. Our study emphasizes the role of CDKL5 mutation screening in cases of atypical Rett syndrome with congenital seizure variant.     

用于白内障超声乳化训练的活体白内障动物模型

目的：制备用于白内障超声乳化训练的活体白内障动物模型。 方法：狗在全身麻醉下用26号带有斜面的针刺破左眼的晶状体前囊，制备白内障模型，形成白内障后，行超声乳化手术。 结果：眼部检查显示晶状体后部皮质混浊开始于穿刺术后5～7d，并于术后75d白内障全部形成，在所有的白内障形成的眼上行超声乳化手术，并植入人工晶状体，所有的狗均恢复了视力。 结论：考虑到无经验的眼科医生在行白内障超声乳化手术的初始阶段引起的巨大损失，我们认为这个活的动物模型明显优于目前用于训练超声乳化手术的尸体眼。     

Combined effects of low-dose oral spironolactone and captopril therapy in a rat model of spontaneous hypertension and heart failure

The effects of low-dose oral spironolactone (SPIRO) in a rat model of hypertensive heart failure (spontaneously hypertensive heart failure rat) were compared with its effects when combined with captopril (CAP). Twenty-six spontaneously rats with hypertensive heart failure were treated with either placebo (CON), SPIRO (20 mg/kg/d by mouth), CAP (100 mg/kg/d by mouth), or both SPIRO and CAP for 12 weeks. This dose of oral SPIRO did not affect blood pressure, left ventricular end-diastolic diameter, left ventricular ejection fraction, plasma atrial natriuretic peptide concentration, or cardiac fibrosis; however, in combination with CAP, it exerted a significant depressor effect after 12 weeks of treatment that was accompanied by increased urine output and decreased urinary protein excretion. These effects were significantly greater than those with CAP treatment alone. A significant increase in plasma aldosterone level was observed only in CON (174 +/- 21%). These data suggest that the addition of low-dose SPIRO to angiotensin I-converting enzyme inhibitor treatment may prevent progression into end-stage congestive heart failure through synergistic effects on diuresis and renoprotection.     

Synovial sarcoma of parapharyngeal and retropharyngeal space: A case report

Synovial sarcoma is a rare tumour of head and neck. It was first described by Pack and Ariel in 1950. Synovial sarcoma is said to be the commonest sarcoma of hands and feet and they are usually found adjacent to the articular surfaces. They rarely occur in extra-articular sites originating from bursa or tendon sheaths. Parapharyngeal space appears to be the site of predilection in most of the cases occurring in the head and neck region. One such case is being reported here along with its management and review of literature.     

Recurrence of vancomycin-resistant Enterococcus stool colonization during antibiotic therapy.

OBJECTIVE: To test the hypothesis that antibiotic therapy may promote recurrence of vancomycin-resistant Enterococcus (VRE) stool colonization in patients who have previously had three consecutive negative stool cultures obtained at least 1 week apart. DESIGN: One-year prospective cohort study examining the effect of antibiotic therapy on recurrence and density of VRE stool colonization in patients who have cleared colonization. Pulsed-field gel electrophoresis (PFGE) was performed to determine whether recurrent VRE strains were the same clone as the previous colonizing strain. SETTING: A Department of Veterans Affairs medical center including an acute care hospital and nursing home. PATIENTS: All patients with at least one stool culture positive for VRE who subsequently had three consecutive negative stool cultures obtained at least 1 week apart. RESULTS: Of the 16 patients who cleared VRE colonization, 13 received antibiotic therapy during the study period. Eight (62%) of the 13 patients who received antibiotics developed recurrent high-density VRE stool colonization (range, 4.9 to 9.1 log10 colony-forming units per gram) during a course of therapy. Five patients had VRE strains available for PFGE analysis; recurrent strains were unrelated to the prior strain in 3 patients, closely related in 1 patient, and indistinguishable in 1 patient. CONCLUSIONS: Antibiotic therapy may be associated with recurrent high-density VRE stool colonization in many patients who have previously had three consecutive negative stool cultures. These patients should be screened for recurrent stool colonization when antibiotic therapy is administered.     

The metabolomics of (+/-)-arecoline 1-oxide in the mouse and its formation by human flavin-containing monooxygenases

The alkaloid arecoline is a main constituent of areca nuts that are chewed by approximately 600 million persons worldwide. A principal metabolite of arecoline is arecoline 1-oxide whose metabolism has been poorly studied. To redress this, synthetic (+/-)-arecoline 1-oxide was administered to mice (20mg/kg p.o.) and a metabolomic study performed on 0-12h urine using ultra-performance liquid chromatography-coupled time-of-flight mass spectrometry (UPLC-TOFMS) with multivariate data analysis. A total of 16 mass/retention time pairs yielded 13 metabolites of (+/-)-arecoline 1-oxide, most of them novel. Identity of metabolites was confirmed by tandem mass spectrometry. The principal pathways of metabolism of (+/-)-arecoline 1-oxide were mercapturic acid formation, with catabolism to mercaptan and methylmercaptan metabolites, apparent CC double-bond reduction, carboxylic acid reduction to the aldehyde (a novel pathway in mammals), N-oxide reduction, and de-esterification. Relative percentages of metabolites were determined directly from the metabolomic data. Approximately, 50% of the urinary metabolites corresponded to unchanged (+/-)-arecoline 1-oxide, 25% to other N-oxide metabolites, while approximately, 30% corresponded to mercapturic acids or their metabolites. Many metabolites, principally mercapturic acids and their derivatives, were excreted as diastereomers that could be resolved by UPLC-TOFMS. Arecoline was converted to arecoline 1-oxide in vitro by human flavin-containing monooxygenases FMO1 (K(M): 13.6+/-4.9muM; V(MAX): 0.114+/-0.01nmolmin(-1)microg(-1) protein) and FMO3 (K(M): 44.5+/-8.0microM; V(MAX): 0.014+/-0.001nmolmin(-1)microg(-1) protein), but not by FMO5 or any of 11 human cytochromes P450. This report underscores the power of metabolomics in drug metabolite mining.     

Undetected vancomycin-resistant Enterococcus stool colonization in a Veterans Affairs Hospital using a Clostridium difficile-focused surveillance strategy.

We examined the point prevalence of undetected vancomycin-resistant Enterococcus (VRE) stool colonization in an institution that screens stool samples submitted for Clostridium difficile testing. Of 112 patients not known to be colonized, 10 (9%) had rectal VRE colonization. A prospective algorithm was effective for identification of colonized patients.