The association of cataract with leukocyte telomere length in older adults: defining a new marker of aging

Lens transparency, or the magnitude of cataract severity, is a potential in vivo marker of aging distinguishable from diagnosed cataract. To explore lens transparency as a marker of aging, we determined its association with leukocyte telomere length (LTL) measured with quantitative polymerase chain reaction. Cataract severity was directly measured in 259 participants, and prevalent cataract and incident cataract surgery were ascertained in 2,750 participants of the Health, Aging, and Body Composition Study. LTL was unassociated with clinical cataract outcomes. Six of 259 had successfully aged lenses and a mean LTL of 5,700 bp, whereas 253/259 with poorly aged lenses had a mean LTL of 4,770 bp. Participants with a 1,000 bp greater mean LTL had nearly half the odds of any cataract (odds ratio = 0.47, 95% confidence interval 0.22-1.02) after adjustment. Lens transparency might be associated with longer LTL in community-dwelling older adults and should be investigated further as a possible biomarker of aging.     

Gerontology research in Georgia

Gerontology research carried out in different scientific centers of Georgia follows the basic directions of most work in this field: epidemiology, investigation of the mechanisms of aging, and finding ways to prevent senile pathologies and to prolong life. The genealogy and epidemiology of long-living peaple have been studied in areas with high occurrence of these people by considering the sex ratio and social status of the long-living, the influence of environmental factors, and the development of senile pathologies. According to the centrosome (centriole) model of aging, the centrosomes and the cytoskeleton, important structures in cellular differentiation and morphogenesis, may be involved in the initiation of the replication senescence mechanism. Our analysis of genetic studies shows that progressive chromosome heterochromatinization (condensation of eu- and heterochromatin regions) occurs in aging. Decreases in the repair processes and increases in the frequency of chromosome aberrations during aging are secondary to this progressive chromosome heterochromatinization. Chromosome heterochromatinization is a key factor in aging but may be reversible under the influence of bioregulators, some chemical substances, and heavy metal salts. The study of chromosome heterochromatinization may provide clues to the potential for prolonging the human lifespan.     

Atypical antipsychotics and effects of muscarinic, serotonergic, dopaminergic and histaminergic receptor binding on insulin secretion in vivo: an animal model

The atypical antipsychotics (AAPs) have been associated with increased risk of type-2 diabetes. Evidence suggests direct, drug-related effects independent of weight gain and although mechanisms underlying this phenomenon are unclear, it has been suggested that the heterogeneous receptor binding profile of the AAPs may influence receptors implicated in glucose metabolism. This study aimed to clarify weight gain-independent mechanisms of AAP-induced changes in insulin secretion by deconstructing their binding profile with representative antagonists. Healthy rats were pretreated with a single subcutaneous dose of darifenacin 6 mg/kg (n=10), a selective M(3) muscarinic antagonist; ketanserin 2mg/kg (n=10), a 5HT(2A) antagonist; raclopride 0.3mg/kg (n=11) a selective D(2)/D(3) antagonist; terfenadine 20mg/kg (n=9) a selective H(1) antagonist; or, vehicle (n=11). Hyperglycemic clamps were employed following injection, providing an index of secretory capacity of pancreatic β-cells. Acute treatment with darifenacin and ketanserin significantly decreased insulin response to glucose challenge as compared to controls, which was confirmed in the darifenacin group by reduced C-peptide levels. Treatment with raclopride resulted in an increased insulin response and a strong tendency to increased C-peptide levels. H(1) blockade did not result in effects on insulin or C-peptide. Results suggest that the effects of antipsychotics on glucose dysregulation may be related to direct inhibitory effects of muscarinic (M(3)) and serotonergic (5HT(2)) antagonism on insulin secretion. Based on the expression of D(2)-like receptors in β-cells, which mediate inhibition of insulin secretion, we propose that prolonged D(2) blockade with antipsychotics may predispose to depletion of insulin stores and an eventual defect in pancreatic compensation.     

Low Dose vs Standard Dose of Antipsychotics for Relapse Prevention in Schizophrenia: Meta-analysis

Background: It remains unknown as to whether the antipsychotic dose needed for the acute-phase treatment of schizophrenia is also necessary for relapse prevention. Aim: To compare the efficacy between standard dose [(World Health Organization daily defined dose (DDD)] vs low dose (≥50% to <1 DDD) or very low dose (<50% DDD) for relapse prevention in schizophrenia. Data source: Double-blind, randomized, controlled trials with a follow-up duration of ≥24 weeks, including ≥2 dosage groups of the same antipsychotic drug for relapse prevention in schizophrenia, were searched using MEDLINE, the Cochrane Central Register of Controlled Trials, and EMBASE (last search: August 2009). Data extraction: Data on overall treatment failure, hospitalization, relapse, and dropouts due to side effects were extracted and combined in a meta-analysis. Data synthesis: Thirteen studies with 1395 subjects were included in this meta-analysis. Compared with the standard-dose treatment, the low-dose therapy did not show any statistically significant difference in overall treatment failure or hospitalization, while the standard dose showed a trend-level (P = .05) superiority in risk of relapse. The very low–dose group was inferior to the standard-dose group in all efficacy parameters. No significant difference was found in the rate of dropouts due to side effects between either standard dose vs low dose or very low dose. Conclusions: Although antipsychotic treatment with ≥50% to <1 DDD may be as effective as standard-dose therapy, there are insufficient clinical trial data to draw firm conclusions on standard- vs low-dose maintenance antipsychotic therapy for schizophrenia.     

Botulinum toxin A versus B in sialorrhea: A prospective,randomized, double‐blind,crossover pilot study in patients with amyotrophic lateral sclerosis or Parkinson's disease

Background: Either botulinum toxins (BoNTs) A and B have been used for improving drooling in different neurological conditions. Methods: Consecutive patients affected by Amyotrophic Lateral Sclerosis (ALS) or Parkinson's Disease (PD) accompanied by severe drooling were randomized to receive botulinum neurotoxin type A (BoNT‐A) or B (BoNT‐B) injections into the salivary glands. Following the first treatment, when sialorrhea returned to baseline (at least three months after the first injection), subjects were re‐treated with the other serotype. Ultrasound‐guided injections into parotid and submandibular glands were bilaterally performed: total doses were 250 U BoNT‐A (Dysport) and 2500 U BoNT‐B (Neurobloc). Objective (cotton roll weight) and subjective (ad hoc clinical scales) evaluations were performed at baseline, after 1 and 4 weeks, and every 4 weeks until drooling returned to baseline. Results: Twenty‐seven patients (15 ALS and 12 PD) were enrolled, fourteen completed the study. BoNT‐A and BoNT‐B treatments gave both subjective and objective improvements in all patients. The latency was significantly shorter after BoNT‐B treatments (3.2 ± 3.7 days) compared to BoNT‐A (6.6 ± 4.1 days; P = 0.002). The mean benefit duration was similar at 75 and 90 days for BoNT‐A and BoNT‐B, respectively (P = NS). The only toxin‐related side effect was a change to saliva thickness. Conclusions: Either 250 U Dysport or 2500 U Neurobloc have similar effectiveness and safety in controlling sialorrhea. BoNT‐B has a shorter latency and comparable duration. Cost analysis, considering the doses used in this study protocol favored BoNT‐B treatment. © 2011 Movement Disorder Society     

Sole stenting of large and giant intracranial aneurysms with self-expanding intracranial stents—limits and complications

Background  

Intracranial aneurysms may be difficult for endovascular treatment due to size, fusiform shape, or wide neck. In such patients, intracranial stents are used to support the coils in the aneurysm sac, or they may be used as a sole stenting technique to divert the blood flow without coils. The aim of this paper is to contribute to the existing data by reviewing the risks of sole stenting of large and giant aneurysms.