Transcranial direct current stimulation for post-stroke dysphagia: a systematic review and meta-analysis of randomized controlled trials

Journal of Neurology - Transcranial direct current stimulation (tDCS) has been investigated as a tool for dysphagia recovery after stroke in several single-center randomized controlled trials...     

Conserved nucleoprotein structure at the ends of vertebrate and invertebrate chromosomes.

Eukaryotic chromosomes terminate with telomeres, nucleoprotein structures that are essential for chromosome stability. Vertebrate telomeres consist of terminal DNA tracts of sequence (TTAGGG)n, which in rat are predominantly organized into nucleosomes regularly spaced by 157 bp. To test the hypothesis that telomeres of other animals have nucleosomes, we compared telomeres from eight vertebrate tissues and cell cultures, as well as two tissues from an invertebrate. All telomeres have substantial tracts of (TTAGGG)n comprising 0.01-0.2% of the genome. All telomeres are long (20-100 kb), except for those of sea urchin, human, and some chicken chromosomes, which are 3-10 kb in length. All of the animal telomeres contained nucleosome arrays, consistent with the original hypothesis. The telomere repeat lengths vary from 151 to 205 bp, seemingly uncorrelated with telomere size, regularity of nucleosome spacing, species, or state of differentiation but surprisingly correlated with the repeat of bulk chromatin within the same cells. The telomere nucleosomes were consistently approximately 40 bp smaller than bulk nucleosomes. Thus, animal telomeres have highly conserved sequences and unusually short nucleosomes with cell-specific structure.     

Structural Analysis of Muscles Elevating the Hyolaryngeal Complex

A critical event of pharyngeal swallowing is the elevation of the hyolaryngeal complex to open the upper esophageal sphincter. Current swallowing theory assigns this function to the submental and thyrohyoid muscles. However, the attachments of the long pharyngeal muscles indicate that they could contribute to this function, yet their role is uninvestigated in humans. In addition, there is evidence the posterior digastric and stylohyoid contribute to hyoid elevation. A cadaver model was used to document the structural properties of muscles. These properties were used to model muscle groups as force vectors and analyze their potential for hyolaryngeal elevation. Vector magnitude was determined using physiological cross-sectional areas (PCSAs) of muscles calculated from structural properties of muscle taken from 12 hemisected cadaver specimens. Vector direction (lines of action) was calculated from the three-dimensional coordinates of muscle attachment sites. Unit force vectors in the superior direction of submental, suprahyoid (which includes the submental muscles), long pharyngeal, and thyrohyoid muscles were derived and compared by an analysis of variance (ANOVA) to document each muscle??s potential contribution to hyolaryngeal elevation. An ANOVA with Tukey HSD post hoc analysis of unit force vectors showed no statistically significant difference between the submental (0.92?±?0.24?cm²) and long pharyngeal (0.73?±?0.20?cm²) muscles. Both demonstrated greater potential to elevate the hyolaryngeal complex than the thyrohyoid (0.49?±?0.18?cm²), with P?<?0.01 and P?<?0.05, respectively. The suprahyoid muscles (1.52?±?0.35?cm²) demonstrated the greatest potential to elevate the hyolaryngeal complex: greater than both the long pharyngeal muscles (P?<?0.01) and the thyrohyoid (P?<?0.01). The submental and thyrohyoid muscles by convention are thought to elevate the hyolaryngeal complex. This study demonstrates that structurally the long pharyngeal muscles have similar potential to contribute to this critical function, with the suprahyoid muscles having the greatest potential. If verified by functional data, these findings would amend current swallowing theory.     

Predictors of Aspiration Pneumonia in Nursing Home Residents

Aspiration pneumonia is a serious problem for the elderly institutionalized person, often requiring transfer to a hospital and a lengthy stay there. It is associated with a high mortality rate and is very costly to the health care system. The current study sought to determine the key predictors of aspiration pneumonia in a nursing home population with the hope that health care providers could identify those residents at highest risk and focus more efforts on prevention of this serious disease. A cross-sectional, retrospective analysis was done, using the Minimum Data Set (MDS) nursing home assessment data for three states (New York, Mississippi, Maine) from 1993 to 1994 (N = 102842). Nursing home residents were aged 65+. Standardized MDS summary scales and their component items were used, including: the Activities of Daily Living (ADL) scale, the cognitive performance scale (CPS), and the Resource Utilization Groups (RUGs). Results of these analyses showed the prevalence of pneumonia among this population was 3% (n = 3118). Results from the logistic regression models indicated 18 significant predictors of aspiration pneumonia. The strongest to weakest predictors of pneumonia were, respectively, suctioning use, COPD, CHF, presence of feeding tube, bedfast, high case mix index, delirium, weight loss, swallowing problems, urinary tract infections, mechanically altered diet, dependence for eating, bed mobility, locomotion, number of medications, and age, while both CVA and tracheotomy care were inversely predictive of pneumonia. The emergence of these significant predictors suggested a different pathogenesis of pneumonia in the elderly nursing home resident from the acute care patient or the outpatient. Nursing home residents have chronic medical conditions that gradually lead to "decompensation" in functional status, nutritional status, and pulmonary clearance. Dysphagia and aspiration are common complications of their medical conditions and may slowly worsen as their status deteriorates. Alternatively, a sudden adverse event may dramatically increase the amount aspirated or the ability to resist infection and lead to sudden decompensation. Clinical staff must identify residents with dysphagia and aspiration and work to prevent decline in functional status in all residents. They must be aware of the dangers of adverse events that lead to sudden inactivity or illness and increase the risk of aspiration pneumonia. Prevention of this disease whenever possible will reduce costs, improve health outcomes, and improve our quality of care.