Enantioselective hydrolysis of some 2-aryloxyalkanoic acid methyl esters and isosteric analogues using a penicillin G acylase-based HPLC monolithic silica column

A technique based on liquid chromatography has been developed to facilitate studies of enantioselectivity in penicillin G acylase (PGA)-catalyzed hydrolysis of some 2-aryloxyalkanoic acid methyl esters and isosteric analogues. PGA was covalently immobilized on an aminopropyl monolithic silica support to create an immobilized HPLC-enzyme reactor. Two sets of experimental data were drawn to calculate the enantioselectivity (E) of the kinetically controlled enantiomer-differentiating reaction, the degree of substrate conversion and the enantiomeric excess of the product. The developed enzymatic reactor was coupled through a switching valve to an achiral analytical column for separation and quantitation of the hydrolysis products. The enantiomeric excess was determined off-line on a PGA-chiral stationary phase. In this way, highly precise E values were determined. A computational study related to the hydrolysis of the considered racemic esters was also carried out in order to unambiguously clarify both the substrate specificity and the enantioselectivity displayed by PGA.     

Influence of bacterial overgrowth and intestinal inflammation on duration of parenteral nutrition in children with short bowel syndrome

OBJECTIVES: Massive intestinal resection results in short bowel syndrome and necessitates prolonged parenteral feeding. The purpose of this work was to assess the impact of late complications of short bowel syndrome, including intestinal bacterial overgrowth and enterocolitis, on the duration of parenteral nutrition (PN) in comparison with factors evident in the neonatal period. METHODS: Retrospective chart review. RESULTS: Of 49 children, 42 were weaned from parenteral nutrition after a treatment course of 17 +/- 14 months. In these 42, postresection small intestinal length equaled 81 +/- 65 cm; 45% had an ileocecal valve. Small intestinal length in the seven children who were PN dependent was 31 +/- 30 cm (p < 0.05); none had an ileocecal valve (p < 0.05). Bacterial overgrowth occurred in all seven PN-dependent children and in 23 of 42 children eventually weaned from PN (p < 0.05). When bacterial overgrowth was identified before weaning (n = 12), the duration pf PN was 28 +/- 17 months, but when bacterial overgrowth was first identified only after weaning (n = 11), the duration of PN was 16 +/- 13 months (p < 0.05). Small intestinal inflammation correlated with bacterial overgrowth (r = 0.69). Those children with severe enteritis identified before weaning remained on the PN regimen for 36 +/- 15 months, in comparison with 21 +/- 14 months in those with mild enteritis and 13 +/- 11 months in those without inflammation (p < 0.02). CONCLUSIONS: Although the length of small intestine remaining after resection is the best immediate predictor of final success in terminating PN in children with short bowel syndrome, PN is prolonged by bacterial overgrowth and associated enteritis in those who will ultimately be weaned.     

Sexually selected vigilance behaviour of the grey partridge is affected by plasma androgen levels

Polymerase chain reaction (PCR) diagnostic methods have rarely been used in epidemiologic studies of Shigella and enteroinvasive Escherichia coli (EIEC) infections. In this study, amplification of the invasion plasmid antigen H (ipaH) gene by PCR and standard culture methods was used to identify Shigella species or EIEC among 154 patients with dysentery, 154 age-matched controls, and family contacts in Thailand. The ipaH PCR system increased the detection of Shigella species and EIEC from 58% to 79% among patients with dysentery and from 6% to 22% among 527 family contacts; 75% of infections in family members were asymptomatic. Detection of the ipaH gene was statistically associated with dysentery. Household contacts of patients with shigellosis diagnosed only by PCR had significantly higher rates of shigellosis than household contacts of patients who did not have Shigella or EIEC infections. Detection of the ipaH gene by PCR is far more sensitive than detection by standard culture and is highly correlated with evidence of Shigella transmission among family contacts.     

Comparison of the WAIS and the WAIS—R in the upper ranges of IQ.

35 medical students were administered 1 of 2 combination forms of the Wechsler Adult Intelligence Scale (WAIS) and the WAIS—Revised (WAIS—R) in a single session, with the WAIS and WAIS—R components presented in a counterbalanced order using a procedure that avoided the repetition of identical items. The WAIS IQ scores were higher than were the WAIS—R IQ scores. The higher the WAIS Full Scale IQ, the smaller the Full Scale IQ difference between the 2 tests. Unexpectedly, the Verbal minus Performance discrepancy was greater on the WAIS—R than on the WAIS. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preparation and release characteristics of dexamethasone acetate loaded organochlorine‐free poly(lactide‐co‐glycolide) nanoparticles

Dexamethasone‐loaded poly(lactide‐co‐glycolide) (PLGA) devices are commonly used as model systems for controlled release. In this study, PLGA nanoparticles containing dexamethasone acetate were prepared by a nanoprecipitation technique in the absence of organochlorine solvents and were characterized by their mean size, ζ potential, scanning electron microscopy, and differential scanning calorimetry to develop a controlled release system. The analytical method for the quantification of dexamethasone acetate by high‐performance liquid chromatography was validated. The results show that it was possible to prepare particles at a nanometric size because the average diameter of the drug‐loaded PLGA particles was 540 ± 4 nm with a polydispersity index of 0.07 ± 0.01 and a ζ potential of ?2.5 ± 0.3 mV. These values remained stable for at least 7 months. The drug encapsulation efficiency was 48%. In vitro tests showed that about 25% of the drug was released in 48 h. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41199.     

A retrospective cohort study of trihalomethane exposure through drinking water and cancer mortality in northern Italy

A few epidemiologic studies have suggested that consumption of drinking water with high trihalomethane content increases the risk of cancer. We investigated the mortality of a cohort of 5144 residents in Guastalla, northern Italy, who were supplied tap water with high chloroform and trihalomethane content between 1965 and 1987. Using death rates of a nearby community as reference rates, the standardized mortality ratio from all cancers between 1987 and 1999 was slightly increased for both males (1.2, 95% confidence interval 1.1-1.4) and females (1.1, 95% confidence interval 1.0-1.3). This was mainly due to a higher mortality from stomach, liver, lung, prostate and bladder cancer in males and from stomach, pancreas, breast and ovarian cancer and lymphocytic leukemia in females. We also noted excess mortality from melanoma in both males and females. Overall, our findings were consistent with an association between trihalomethane exposure and increased cancer risk at some sites. However, the point estimates were statistically imprecise, due to the limited number of deaths for some site-specific cancers. In addition, we were unable to rule out the possibility of confounding due to smoking and other life-style factors with regard to some of the excess rates.     

Convergence of quantum dot barcodes with microfluidics and signal processing for multiplexed high-throughput infectious disease diagnostics

Through the convergence of nano- and microtechnologies (quantum dots and microfluidics), we have created a diagnostic system capable of multiplexed, high-throughput analysis of infectious agents in human serum samples. We demonstrate, as a proof-of-concept, the ability to detect serum biomarkers of the most globally prevalent blood-borne infectious diseases (i.e., hepatitis B, hepatitis C, and HIV) with low sample volume (<100 microL), rapidity (<1 h), and 50 times greater sensitivity than that of currently available FDA-approved methods. We further show precision for detecting multiple biomarkers simultaneously in serum with minimal cross-reactivity. This device could be further developed into a portable handheld point-of-care diagnostic system, which would represent a major advance in detecting, monitoring, treating, and preventing infectious disease spread in the developed and developing worlds.     

Self-alignment method for solution-processable dielectric structures via joule heating

We present a versatile method to create self-aligned patterns of polymer dielectric on metal by the use of Joule heating. In contrast to global thermal or light based curing, the method self-aligns the dielectric to a metal pattern on the substrate. A current-induced temperature rise along a metal line cures the insulator locally; uncured material is then removed by rinsing with solvent. We have obtained very promising results for aligning thermally cross-linkable and selectively baked dielectrics. Alignment of cross-linkable polymers is less sensitive to the rinsing step than selectively baked dielectrics. Finite-element simulations were used to determine the range of suitable curing current. After optimization of the curing parameters high yield and low leakage dielectrics were obtained.