Oxidative stress in term small for gestational age neonates born to undernourished mothers: a case control study

Background  

The objective of this study was to assess the status of oxidative stress in term small for gestational age (SGA) newborn infants born to undernourished mothers by estimating levels of erythrocyte superoxide dismutase (SOD), catalase, reduced glutathione, and serum malondialdehyde (MDA) in cord blood and comparing them to healthy appropriate for gestational age (AGA) controls. This was done in a case control design at a tertiary level teaching hospital.     

New support for branched-chain amino acid supplementation in advanced hepatic failure

Nutritional supplementation with branched-chain amino acids (BCAA) has been a topic of considerable debate for more than two decades. Several studies have demonstrated that supplementation with BCAA is associated with improvement of the catabolic state commonly seen in people with cirrhosis, whereas other studies have showed an improvement in portosystemic encephalopathy in patients with liver disease. Some studies have also shown there to be no benefit in BCAA supplementation in advanced cirrhosis. A recent large clinical trial showed that long-term BCAA supplementation may be useful in preventing progressive hepatic failure and improving liver function in some patients.     

Predicting response to rhDNase and hypertonic saline in children with cystic fibrosis

Daily recombinant human deoxyribonuclease (rhDNase) is an established but expensive treatment in cystic fibrosis (CF). Alternate-day rhDNase and hypertonic saline (HS) represent potential cheaper alternative therapies. However, not all patients improve on treatment. To assess response, many CF centers have developed formal n-of-1 trials of treatment to find out who benefits. Response to daily rhDNase at 3 months has been shown to be a good predictor of response at 1 year. There are no data correlating individual response at a shorter time period with 3-month response. We assessed whether individual responses to daily rhDNase, alternate-day rhDNase, and HS could be predicted from lung function response at 6 weeks, thus shortening the n-of-1 trial, or from baseline patient characteristics, therefore avoiding the need for an n-of-1 trial. In a randomized crossover trial, 48 CF children were allocated consecutively to 12 weeks of once-daily 2.5-mg rhDNase, alternate-day 2.5-mg rhDNase, and twice-daily 5 ml of 7% HS. Forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC) were measured at baseline and then at 6 and 12 weeks into each treatment period. Lung function response to the drugs at 6 weeks was highly predictive of response at 3 months. There was some evidence that response to HS was worse in patients with lower baseline lung function. However, there was no association between response to alternate-day or daily rhDNase and baseline characteristics. In conclusion, response to rhDNase and HS at 6 weeks was highly predictive of response at 3 months. For daily and alternate-day rhDNase, at least, the drug needs to be administered for at most 6 weeks initially to assess long-term response to treatment. Response to treatment could not be reliably predicted from baseline characteristics.     

Expression of a catalytically inactive transmembrane protein tyrosine phosphatase epsilon (tm-PTP epsilon) delays optic nerve myelination

Reversible tyrosine phosphorylation is integral to the process of oligodendrocyte differentiation. To interfere with the subset of the phosphorylation cycle overseen by protein tyrosine phosphatase epsilon (PTP epsilon) in oligodendrocytes, we applied a substrate-trapping approach in the development of transgenic mice overexpressing a catalytically inactive, transmembrane PTP epsilon-hemaglutinin (tm-PTP epsilon-HA) from the dual promoter element of the gene encoding the myelin protein 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP). Transgene expression peaked during the active myelinating period, at 2-3 weeks postnatal. Two tyrosine phosphoproteins, alpha-enolase and beta-actin, were phosphorylated to a greater degree in transgenic mice. Despite a high degree of tm-PTP epsilon-HA expression, myelin was grossly normal in nearly all axonal tracts. Phenotypic abnormalities were limited to optic nerve, where a decrease in the degree of myelination was reflected by reduced levels of myelin proteins on postnatal day 21 (PND21), as well as a decrease in the density of differentiated oligodendrocytes. The optic chiasm was reduced in thickness in transgenic mice; optic nerves similarly exhibited a reduction in transverse width. Further analyses of the optic pathway demonstrated that transgenic protein was unexpectedly present in retinal ganglion cells, whose axons are the targets of myelination by optic nerve oligodendrocytes. On PND28, transgenic protein declined dramatically in both oligodendrocytes and retinal ganglion cells contributing to the recovery of optic nerve myelination. Thus, delayed myelination arises only when tm-PTP epsilon-HA is simultaneously expressed in myelin-forming glia and their neuronal targets. While tm-PTP epsilon related signaling pathways may figure in axon-glial interactions, interfering with tm-PTP epsilon activity does not perceptibly affect the development or myelinating capacity of most oligodendrocytes.     

Conversion to dementia among two groups with cognitive impairment. A preliminary report

OBJECTIVE: To determine the conversion rates to dementia in patients diagnosed with mild cognitive impairment (MCI) thought to be caused by incipient Alzheimer's disease (MCI-AD) or with MCI with features of vascular disease (MCI-Vas). METHODS: On the basis of patient history, neurocognitive, neurological and MRI evaluation, 99 patients were diagnosed with MCI-AD and 35 with MCI-Vas. Conversion to dementia over an average of a 2.4 +/- 1.8-year period was determined. RESULTS: Over the follow-up period, 44% converted to dementia, 51.5% remained classified as MCI, and 4.5% were reclassified as cognitively normal. The conversion rate to dementia was significantly faster at 3 years for the MCI-AD (50.5%) than for the MCI-Vas group (25.7%). The neuropsychological test found to best differentiate converters from non-converters was the Fuld-OME, a measure of learning and recall. Age, education, gender or APOE epsilon4 allele frequency did not differentiate converters from non-converters. CONCLUSIONS: MCI-AD and MCI-Vas are clinically meaningful subtypes of MCI that may convert to dementia at different rates. Prospective studies on larger subsets of MCI patients are required to confirm these findings.     

Stability and Solubility of Celecoxib-PVP Amorphous Dispersions: A Molecular Perspective

PURPOSE: The purpose of the current study is to evaluate the solubility advantage offered by celecoxib (CEL) amorphous systems and to characterize and correlate the physical and thermodynamic properties of CEL and its amorphous molecular dispersions containing poly(vinylpyrrolidone) (PVP). METHODS: The measurement of crystalline content, glass transition temperatures, and enthalpy relaxation was performed using differential scanning calorimetry. Solubility and dissolutions studies were conducted at 37 degrees C to elucidate release mechanisms. Further, the amorphous systems were characterized by polarized light microscopy and X-ray powder diffraction studies. RESULTS: The PVP content has a prominent effect on the stability and solubility profiles of amorphous systems. A dispersion of 20% w/w PVP with CEL resulted in a maxima in terms of solubility enhancement and lowering of relaxation enthalpy. The release of drug from amorphous molecular dispersions was found to be drug-dependent and independent of the carrier. CONCLUSIONS: The solubility enhancement and enthalpy relaxation studies with respect to PVP concentration helped in a better prediction of role of carrier and optimization of concentration in the use of solid dispersions or amorphous systems. The drug release mechanism is drug-controlled rather than carrier-controlled.     

Quantile estimation following non-parametric phase I clinical trials with ordinal response

A non-parametric multi-dimensional isotonic regression estimator is developed for use in estimating a set of target quantiles from an ordinal toxicity scale. We compare this estimator to the standard parametric maximum likelihood estimator from a proportional odds model for extremely small data sets. A motivating example is from phase I oncology clinical trials, where various non-parametric designs have been proposed that lead to very small data sets, often with ordinal toxicity response data. Our comparison of estimators is performed in conjunction with three of these non-parametric sequential designs for ordinal response data, two from the literature and a new design based on a random walk rule. We also compare with a non-parametric design for binary response trials, by keeping track of ordinal data for estimation purposes, but dichotomizing the data in the design phase. We find that a multidimensional isotonic regression-based estimator far exceeds the others in terms of accuracy and efficiency. A rule by Simon et al. (J. Natl. Cancer Inst. 1997; 89:1138-1147) yields particularly efficient estimators, more so than the random walk rule, but has higher numbers of dose-limiting toxicity. A small data set from a leukemia clinical trial is analysed using our multidimensional isotonic regression-based estimator.     

Respiratory and general health impairments of ragpickers in India: a study in Delhi

Objective: This study attempted to assess the respiratory and general health of ragpickers who rummage through the garbage dumps and landfill sites in India to collect and sell recyclable materials for a living. Methods: 98 ragpickers and 60 controls from Delhi, matched for age, sex, and socioeconomic conditions, were examined. Health data were obtained from questionnaire survey, clinical examination, and laboratory investigations. Lung function was evaluated by spirometry. Results: After controlling for smoking as a confounder, respiratory symptoms and lung function decrement were recorded in 94% and 52% of the ragpickers, respectively, compared with 56% and 34% of controls. The ragpickers showed a higher prevalence of low hemoglobin, high circulating eosinophil and monocyte counts, unhealthy gums, frequent diarrhea, and dermatitis, when compared with controls. Their sputum showed an abundance of alveolar macrophages, siderophages and inflammatory cells, and a very high frequency of squamous metaplasia and dysplasia of bronchial epithelial cells, suggesting inflammation and cellular changes in the airways. Conclusion: The ragpickers suffer from a multitude of health problems which seem related to their occupation.