Thiophilic interaction chromatography (TIC) of amyloid-beta protein precursor

Neuritic plaques, one of the diagnostic characteristics of an AD, contain extracellular deposits of amyloid-beta (Abeta) derived from amyloid-beta protein precursor (AbetaPP). The objective of this study was to extract AbetaPP out of HEK293 cells and to purify it. Two procedures were chosen for purification of AbetaPP: Thiophilic Interaction Chromatography (TIC) and molecular sieving. Using Superdex 75, Superose 12, and Fractogel gel matrices, AbetaPP was isolated on HPLC. The chromatograms illustrate the purification of AbetaPP. Our method describes a new and elegant way for the extraction and purification of AbetaPP from HEK293 cell lines using thiophilic interaction chromatography (TIC).     

Sodium signals in cerebellar Purkinje neurons and Bergmann glial cells evoked by glutamatergic synaptic transmission

Glial cells express specific high-affinity transporters for glutamate that play a central role in glutamate clearance at excitatory synapses in the brain. These transporters are electrogenic and are mainly energized by the electrochemical gradient for sodium. In the present study, we combined somatic whole-cell patch-clamp recordings with quantitative Na+ imaging in fine cellular branches of cerebellar Bergmann glial cells and in dendrites of Purkinje neurons to analyze intracellular Na+ signals close to activated synapses. We demonstrate that pressure application of glutamate and glutamate agonists causes local Na+ signals in the mM range. Furthermore, we analyzed the pharmacological profile, as well as the time course and spatial distribution of Na+ signals following short synaptic burst stimulation of parallel or climbing fibers. While parallel fibers stimulation resulted in local sodium transients that were largest in processes close to the stimulation pipette, climbing fibers stimulation elicited global sodium transients throughout the entire cell. Glial sodium signals amounted to several mM, were mainly caused by sodium influx following inward transport of glutamate and persisted for tens of seconds. Sodium transients in dendrites of Purkinje neurons, in contrast, were mainly caused by activation of AMPA receptors and had much faster kinetics. By reducing the driving force for sodium-dependent glutamate uptake, intracellular sodium accumulation in glial cells upon repetitive activity might provide a negative feedback mechanism, promoting the diffusion of glutamate and the activation of extrasynaptic glutamate receptors at active synapses in the cerebellum.     

Genotoxic and endocrine activities of bis(hydroxyphenyl)methane (bisphenol F) and its derivatives in the HepG2 cell line

Human can be exposed to bis(hydroxyphenyl)methane (bisphenol F or BPF) and its derivatives as environment and food's contaminants. This study was investigated to identify and to compare toxic potency of BPF, BFDGE, and two of BPF metabolites using in vitro methods. BPF did not induce any genic mutation in bacteria when the Ames test was performed according to the OECD guideline. In contrast, using Human cell lines and Comet assay, we demonstrated that BPF and Bisphenol F Diglycidyl Ether (BFDGE) were effective on HepG2 cell DNA fragmentation at non-cytotoxic concentrations. DHB was also positive but at higher concentrations, near its limit of solubility. Neither BPF, nor DHB induced a positive response in the micronucleus assay. The increase of micronuclei observed when cells were exposed to BFDGE was mostly due to a cytotoxic effect. Concerning endocrine activities, BPF increased the luciferase activity in HepG2 cells transiently transfected with a concentration dependant pattern, DHB also induced a positive response but at highest concentrations. Estrogenic responses in the HepG2 cells differed with the estrogen receptor (ER) involved. Using MDA-kb2 cell line stably transfected with pMMTV-neo-Luc, only BPF was anti-androgenic at the highest concentration (10(-5)M). Then, we demonstrated using human cell lines, especially HepG2, BPF was the most toxic compound in term of genotoxicity and endocrine activities compared to DHB and BPF-OH, the free metabolites identified in rat urine when BPF was administrated to rats.     

Leptin, lipid and lipid metabolism-related hormones in chronic renal failure in Arabia

SUMMARY: In patients with chronic renal failure (CRF), hyperleptinaemia has been widely reported, but the exact mechanisms leading to elevated leptin levels are unclear. Impaired renal clearance of leptin and the influence of other hormones may be important. In this study, we measured serum leptin levels in 150 patients on haemodialysis, peritoneal dialysis or in the predialysis phase of CRF. Furthermore, we measured plasma levels of insulin, growth hormone (GH) and insulin-like growth factor 1 (IGF-1), as well as plasma levels of triacylglycerols and total low density lipoprotein (LDL)- and high density lipoprotein (HDL)-cholesterol. We observed significantly elevated levels of leptin, particularly in female patients, and leptin was shown to correlate significantly with insulin, total and LDL-cholesterol and log triacylglycerols. Leptin was inversely correlated with GH concentrations, but was not correlated with IGF-1 levels. Despite the multiple correlations established between leptin levels and other variables, only hyperinsulinaemia in CRF seems to be important as a determinator of leptin levels.     

Chest compressions performed by ED staff: a randomized cross-over simulation study on the floor and on a stretcher

Background

Multiple factors may contribute to the observed survival variability following in-hospital cardiopulmonary resuscitation (CPR). While in-hospital CPR is most often performed on patients lying on a bed or stretcher, CPR training uses primarily manikins placed on the floor. We analyzed the quality of external chest compressions (ECC) in simulated cardiac arrest scenarios occurring both on a stretcher and on the floor.

Methods

Prospective cross-over simulation study enrolling ED nurses and nurse's aides as part of an annual evaluation. Simulated CPR was performed in the 2 rescuer-mode for 2 min, both kneeling on the floor, and standing beside a knee high stretcher. The order of position was randomized. ECC parameters were compared.

Results

ED nurses (n = 48) and nurse's aides (n = 26) performed 128 scenarios. Mean ECC depth was 32 ± 13 mm on the floor and 27 ± 11 mm on a stretcher (?: 5 mm, 95%CI [3-7], P < .001). Participants last trained within a year (n = 17) developed deeper ECCs than their colleagues (n = 47) in both positions (floor: 39 ± 12 mm vs stretcher: 34 ± 11 mm (p = 0.016) for those trained within the year, and floor: 29 ± 12 mm vs stretcher: 24 ± 10 mm (P < .001) for those trained over a year ago).

Conclusions

The quality of chest compressions performed by ED staff was below 2005 guideline standards, with decreased ECC depth during CPR on a stretcher. Annual refresher courses should be implemented in the ED, with a focus on obtaining required ECC depth while standing next to a stretcher.     

Spinal anesthesia for endoscopic urological surgery--low dose vs. varying doses of hyperbaric bupivacaine

BACKGROUND AND OBJECTIVE: The aim of this study is to compare the efficiency of low dose vs. varying doses of hyperbaric bupivacaine in spinal anesthesia for endoscopic urological procedures. METHODS: Sixty consecutive patients were studied in a randomized prospective manner. They received either of 5 (Gr I), 7.5 (Gr II) or 10 mg (Gr III) of hyperbaric bupivacaine 0.5% combined with 25 microg of fentanyl, through a 25-gauge W hitacre spinal needle placed in the L3-L4 interspace. Characteristics of sensory and motor block, dose of ephedrine required, secondary effects, the patients, and the surgeons satisfaction, were noted. RESULTS: The maximum number of blocked segments was 14 +/- 1 (Gr I), 15 +/- 2 (Gr II) and 16 +/- 2 (Gr III). Time to T12 regression was significantly shorter for Gr I (53 +/- 13 min) than for Gr II (69 +/- 20 min) or Gr III (94 +/- 14 min). Bromage 3 block was not found in Gr I compared to 4 patients in Gr II and 15 patients in Gr III. The duration of motor block was shorter in Gr 1(51 +/- 18 min) than in Gr II (86 +/- 19 min) and in Gr III (138 +/- 21 min). Ephedrine was used for 16 patients in Gr III (9.8 +/- 12.2 mg), 5 patients in Gr II (3.7 +/- 7.8 mg) and 2 patients in Gr I (0.5 +/- 1.5 mg). The difference is statistically significant between Gr III and the other groups. CONCLUSIONS: These results suggest that the use of a low dose of bupivacaine (5 mg) added to fentanyl (25 microg) for endoscopic urological surgery, resulted in short-acting sensory block, without motor block and a lower incidence of cardiovascular side effects, as compared to either of 7.5 or 10 mg bupivacaine with 25 microg fentanyl.     

Male knowledge, attitudes, and family planning practices in northern Nigeria

This paper examines the linkages between socioeconomic characteristics, attitudes, and familial contraceptive use. Past family planning programs in Nigeria have been mainly directed toward women. However, because northern Nigeria (and to a slightly lesser extent all of Nigeria) remains a patrilineal society characterised by early age at marriage for women, men at present continue to determine familial fertility and contraceptive decisions. Consequently, at least for the time period relevant for current policy planning purposes, the willingness of husbands to adopt or allow their spouses to use family planning practices will determine the pace of fertility reduction in Nigeria. The results suggest that there is high knowledge of contraceptives, a generally negative attitude towards limiting family size for economic reasons, and consequently low rates of contraceptive use. Respondents who were willing to use contraceptives were more willing to use them for child spacing purposes than explicitly for limiting family size. Path-analytic decompositions of the effects of predictor variables show that education has the largest direct and total effects on contraceptive use while specific knowledge of contraceptives has the smallest direct and total effect (as well as a paradoxical negative direct effect when education is included in the model). Most importantly, attitudes have the largest direct effect on contraceptive use with a standardized coefficient value of 781. Thus, since knowledge of contraceptive is already high among even those respondents who do not use contraceptives, the attitudes of males are especially important for decisions about contraceptive use. As a result, family planning programs that continue to focus solely on women will continue to achieve only limited successes in northern Nigeria (and likely in the many patrilineal societies where similar programs are pursued).