A single pentylenetetrazole-induced clonic-tonic seizure episode is accompanied by a slowly developing cognitive decline in rats

According to different studies, between 5% and 10% of people suffer a single isolated seizure episode at some time in their life. However, little is known about the effects of a single seizure episode on cognitive function, and clinical investigations of this issue are not easy to perform. In this situation, animal models may be a reasonable choice. The aim of our study was to follow the time course of delayed effects of generalized clonic-tonic convulsions on learning and memory functions in rats. A clonic-tonic seizure episode was induced by a single i.p. injection of pentylenetetrazole (70 mg/kg). Different behavioral tests were performed between days 10 and 100 after the convulsant administration. A single seizure episode resulted in a gradual decline in short-term memory function as assessed by novel object recognition and social recognition tests. The seizure episode induced a quick increase in hippocampal cell proliferation; however, the excessive newly generated cells seemed to be eliminated by the time of obvious cognitive impairment. These observations are indicative of a slowly developing and long-lasting influence of a single seizure episode on cognitive function. A rather long time period between the seizure episode and the manifestations of cognitive decline provides a window for a possible therapeutic intervention, and an elaboration of such “post-conditioning” treatments may be a promising opportunity to prevent subsequent mental impairments in patients.     

Isolated calf deep vein thrombosis in the community setting: the Worcester Venous Thromboembolism study

The prevalence of isolated calf deep vein thrombosis (DVT) in the community setting is relatively unexplored. Confusion remains with regards to its management and contemporary natural history. The purpose of this investigation was to describe the number of cases of calf DVT in the community, use of early management strategies, and rates of venous thromboembolism (VTE) recurrence and major bleeding. The medical records of residents of the Worcester (MA) metropolitan area with ICD-9 codes consistent with potential VTE during 4 study years (1999/2001/2003/2005) were validated by trained nurses. Patient demographic/clinical characteristics, treatment practices, and outcomes were evaluated. Isolated calf DVT was diagnosed in 166 (11.1%) of 1,495 patients with lower extremity DVT. Patients with calf DVT were less likely to be discharged on anticoagulants or with an IVC filter than patients with proximal DVT (84.1 vs. 92.3%). The rates of VTE recurrence and pulmonary embolism did not differ significantly between patients with calf DVT and proximal DVT at 6 months (11.0 vs. 8.7%, 2.6 vs. 1.8%, respectively). Patients with calf DVT had higher adjusted risk of early (14-day) VTE recurrence/extension (OR 2.34, 95% CI 1.01–5.44). Patients with calf DVT had lower rates of major bleeding at 6 months compared to patients with proximal DVT (5.2 vs. 9.3%, P = 0.04). Rates of recurrent VTE and major bleeding following calf DVT in the community are much higher than in randomized clinical trials of patients with proximal or calf DVT. Further study of management strategies for isolated calf DVT is needed.     

Design and synthesis of lipid-mimetic cationic iridium complexes and their liposomal formulation for in vitro and in vivo application in luminescent bioimaging

Two iridium [Ir(N^C)₂(N^N)]⁺ complexes with the diimine N^N ligand containing a long polymethylene hydrophobic chain were synthesized and characterized by using NMR and ESI mass-spectrometry: N^N – 2-(1-hexadecyl-1H-imidazol-2-yl)pyridine, N^C – methyl-2-phenylquinoline-4-carboxylate (Ir1) and 2-phenylquinoline-4-carboxylic acid (Ir2). These complexes were used to prepare the luminescent PEGylated DPPC liposomes (DPPC/DSPE-PEG2000/Ir-complex = 95/4.5/1 mol%) using a thin film hydration method. The narrowly dispersed liposomes had diameters of about 110 nm. The photophysics of the complexes and labeled liposomes were carefully studied. Ir1 and Ir2 give red emission (λ_em = 667 and 605 nm) with a lifetime in the microsecond domain and quantum yields of 4.8% and 10.0% in degassed solution. Incorporation of the complexes into the liposome lipid bilayer results in shielding of the emitters from interaction with molecular oxygen and partial suppression of excited state nonradiative relaxation due to the effect of the relatively rigid bilayer matrix. Delivery of labeled liposomes to the cultured ARPE-19 cells demonstrated the usefulness of Ir1 and Ir2 in cellular imaging. Labeled liposomes were then injected intravitreally into rat eyes and imaged successfully with optical coherence tomography and funduscopy. In conclusion, iridium complexes enabled the successful labeling and imaging of liposomes in cells and animals.

Novel lipoidal Ir(iii) phosphorescent labels were embedded into liposomes and used for imaging in cells and animals.     

A truncation in the RYR1 gene associated with central core lesions in skeletal muscle fibres

A novel single-nucleotide deletion in exon 100 of the RYR1 gene, corresponding to deletion of nucleotide 14,510 in the human RyR1 mRNA (c14510delA), was identified in a man with malignant hyperthermia and in his two daughters who were normal for malignant hyperthermia. This deletion results in a RyR1 protein lacking the last 202 amino acid residues. All three subjects heterozygotic for the mutated allele presented with a prevalence of type 1 fibres with central cores, although none experienced clinical signs of myopathy. Expression of the truncated protein resulted in non-functional RYR1 calcium release channels. Expression of wild-type and RyR1(R4836fsX4838) proteins resulted in heterozygotic release channels with overall functional properties similar to those of wild-type RyR1 channels. Nevertheless, small differences in sensitivity to calcium and caffeine were observed in heterotetrameric channels, which also presented an altered assembly/stability in sucrose-gradient centrifugation analysis. Altogether, these data suggest that altered RYR1 tetramer assembly/stability coupled with subtle chronic changes in Ca2+ homoeostasis over the long term may contribute to the development of core lesions and incomplete malignant hyperthermia susceptibility penetrance in individuals carrying this novel RYR1 mutation.     

Multipoint dilution hemofiltration: A new technology for maximum convective clearance

Convection-based renal replacement therapies (RRTs) have the potential to improve patient outcomes when compared to diffusion-based RRT such as hemodialysis (HD), but have limited clearance rates. We propose and characterize multipoint dilution hemofiltration (MPD-HF), a purely convective blood purification technology which removes the fundamental filtration limit associated with convective RRT resulting in clearance rates on par with HD. In MPD-HF, filtration of liquid and solutes occurs along the length of the hollow fibers that convey the blood, and substitution fluid is pushed into the fibers at multiple points along their length. Since multiple filtration and dilution steps are contained within one pass of the blood through the hollow fiber, the fraction of fluid that can be filtered may be increased to allow a high clearance rate that removes a wide range of toxins. In vitro tests yielded an average steady-state filtrate fraction of 68%, exceeding commercial HDF cartridge filtrate fractions by a factor of approximately 3. The molecular weights of molecules cleared spans up to the cutoff of 66 kDa for albumin.     

Highly potent analgesic activity of monoterpene-derived (2S,4aR,8R,8aR)-2-aryl-4,7-dimethyl-3,4,4a,5,8,8a-hexahydro-2H-chromene-4,8-diols

New chiral heterocyclic compounds with a hexahydro-2H-chromene framework were synthesized by reactions of (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol with aromatic aldehydes in the presence of montmorillonite clay. The analgesic activity of the compounds was studied in vivo. The majority of these compounds showed significant analgesic activity in the acetic acid-induced writhing test; the compounds containing one hydroxy and one methoxy substituents also showed analgesic activity in the hot-plate test. (2S,4aR,8R,8aR)-2-(3-Hydroxy-4-methoxyphenyl)-4,7-dimethyl-3,4,4a,5,8,8a-hexahydro-2H-chromene-4,8-diol was as effective as the diclofenac sodium reference taken in the same dose in both tests. It has low acute toxicity and is very promising for further development.     

The impact of preventive health behaviour and social factors on visits to the doctor

Background

The aim of this study is to examine the joint impact of preventive health behavior (PHB) and social and demographic factors on the utilization of primary and secondary medical care under a universal health care system, as measured by visits to the doctor, who were categorized as either a General Practitioner (GP) or Specialist Doctor (SD).

Methods

An ordered probit model was utilized to analyze data obtained from the 2009 Israeli National Health Survey. The problem of endogeneity between PHB factors and visits to GP was approached using the two-stage residuals inclusion and instrumental variables method.

Results

We found a positive effect of PHB on visits to the doctor while the addition of the PHB factors to the independent variables resulted in important changes in explaining visits to GP (in values of the estimates, in their sign, and in their statistical significance), and only in slight changes for visits to SD. A 1% increase in PHB factors results in increasing the probability to visit General Practitioner in the last year in 0.6%. The following variables were identified as significant in explaining frequency of visits to the doctor: PHB, socio-economic status (pro-poor for visits to GP, pro-rich for visits to SD), location (for visits to SD), gender, age (age 60 or greater being a negative factor for visits to GP and a positive factor for visits to SD), chronic diseases, and marital status (being married was a negative factor for visits to GP and a positive factor for visits to SD).

Conclusions

There is a need for allowing for endogeneity in examining the impact of PHB, social and demographic factors on visits to GP in a population under universal health insurance.For disadvantaged populations with low SES and those living in peripheral districts, the value of IndPrev is lower than for populations with high SES and living in the center of the country. Examining the impact of these factors, significant differences in the importance and sometimes even in the sign of their influence on visits to different categories of doctors - GP and SD, are found.

     

Advancing high-resolution manometry: evaluating the use of multiple rapid swallows versus apple viscous swallows in clinical practice

Esophagus - High-Resolution Manometry (HRM) with provocative maneuvers, such as Multiple Rapid Swallows (MRS) and Apple Viscous Swallows (AVS), is commonly utilized to diagnose esophageal...