Behavioral impairments of the aging rat

Several disturbances occurring during aging of humans and rodents alike stem from changes in sensory and motor functions. Using a battery of behavioral tests we have studied alterations in performance with advancing age in female and male rats of some frequently used strains. In parallel, we collected survival and body weight data. The median survival age was similar for female and male Sprague-Dawley rats, inbred female Lewis and outbred male Wistar rats (29-30 months). In contrast, male Fisher 344 had a significantly shorter median life span. During aging there is a gradual decline in locomotor activity and explorative behavior while disturbances of coordination and balance first became evident at more advanced age. In old age, also weight carrying capacity, limb movement and temperature threshold were impaired. While whole body weight continues to increase over the better part of a rats' life span, the behavioral changes in old age associated with a decrease in both total body weight and muscle mass. Dietary restriction increases median life span expectancy; retards the pace of behavioral aging and impedes sarcopenia. Housing in enriched environment did not improve the scoring in the behavioral tests but tended to increase median life span. Finally, there was an agreement between behavioral data collected from longitudinal age-cohorts and those obtained from multiple age-cohorts.     

Activation of the cortical pain network by soft tactile stimulation after injection of sumatriptan

The anti-migraine drug sumatriptan often induces unpleasant somatosensory side effects, including a dislike of being touched. With a double-blind cross-over design, we studied the effects of sumatriptan and saline on perception (visual analogue scale) and cortical processing (functional magnetic resonance imaging) of tactile stimulation in healthy subjects. Soft brush stroking on the calf (n=6) was less pleasant (p<0.04) and evoked less activation of posterior insular cortex in the sumatriptan compared to the saline condition. Soft brushing activated pain processing regions (anterior insular, lateral orbitofrontal, and anterior cingulate cortices, and medial thalamus) only in the sumatriptan condition, whereas activation of somatosensory cortices was similar in both conditions. Soft brush stroking on the palm (n=6) was equally pleasant in both conditions. One possible mechanism for the activation of pain processing regions by brush stroking is sensitization of nociceptors by sumatriptan. Another possibility is inhibition of a recently discovered system of low-threshold unmyelinated tactile (CT) afferents that are present in hairy skin only, project to posterior insular cortex, and serve affective aspects of tactile sensation. An inhibition of impulse transmission in the CT system by sumatriptan could disinhibit nociceptive signalling and make light touch less pleasant. This latter alternative is consistent with the observed reduction in posterior insular cortex activation and the selective effects of stimulation on hairy compared to glabrous skin, which are not explained by the nociceptor sensitization account.     

Laparoscopic Roux-En-Y Gastric Bypass is Effective and Safe in Over 55-year-old Patients: A Comparative Analysis

Background

Controversy exists regarding the effectiveness and safety of laparoscopic Roux-en-Y gastric bypass (LRYGB) in elderly patients. We evaluated our outcomes of LRYGB in patients aged ≥55 years.

Methods

A total of 549 consecutive patients underwent LRYGB as primary operation and 132 were ≥55 years old. Patients were divided in two groups: group <55 years comprised 417 patients, with mean age (±SD) of 41.15 ± 8.47 years; group ≥55 years comprised 132 patients, with mean age of 59.43 ± 3.81 years. Mean preoperative body mass index was 47.01 ± 7.47 and 46.21 ± 7.47 respectively, whereas mean excess weightloss percent (EW%) was 88.06 ± 30.28 and 84.86 ± 29.87 %. Early morbidity (30 days) and outcomes at 6, 12, and 24 months follow-up were evaluated.

Results

Significant difference was found in operative time (84.19 ± 29.05 vs. 90.89 ± 30.95 min, p = 0.03). One conversion to open procedure occurred in group <55 years, whereas three occurred in group ≥55 years (p = 0.04). Intraoperative complications occurred in 22 patients (5.27 %) in group <55 years versus 19 in group ≥55 years (14.39 %), which was statistically significant (p = 0.001). One case of death occurred in the younger group. Overall postoperative morbidity rate was 18.7 % in group <55 years and 25.76 % in group ≥55 years, with no significant difference (p = 0.08). Mean EWL% at 12 months in group <55 years was 65.95.05 ± 26.96 versus 62.61 ± 41.78 in group ≥55 years, whereas at 24 months it was 65.08 ± 29.68 versus 64.48 ± 18.44 with no significant difference between the groups (p = 0.51; p = 0.92).

Conclusions

LRYGB for patients ≥55 years achieves outcomes and complications rates comparable to the younger population. Patients should not be denied bariatric surgery for the age alone.     

Elevated Concentrations of Neurofilament Light Chain in the Cerebrospinal Fluid of Bipolar Disorder Patients

Bipolar disorder (BD) is characterized by mood swings between manic and depressive states. The etiology and pathogenesis of BD is unclear, but many of the affected cognitive domains, as well as neuroanatomical abnormalities, resemble symptoms and signs of small vessel disease. In small vessel disease, cerebrospinal fluid (CSF) markers reflecting damages in different cell types and subcellular structures of the brain have been established. Hence, we hypothesized that CSF markers related to small vessel disease may also be applicable as biomarkers for BD. To investigate this hypothesis, we sampled CSF from 133 patients with BD and 86 healthy controls. The concentrations of neurofilament light chain (NF-L), myelin basic protein (MBP), S100B, and heart-type fatty acid binding protein (H-FABP) were measured in CSF and analyzed in relation to diagnosis, clinical characteristics, and ongoing medications. Hereby we found an elevation of the marker of subcortical axonal damage, NF-L, in bipolar subjects. We also identified positive associations between NF-L and treatment with atypical antipsychotics, MBP and lamotrigine, and H-FABP and lithium. These findings indicate axonal damage as an underlying neuropathological component of bipolar disorder, although the clinical value of elevated NF-L remains to be validated in follow-up studies. The associations between current medications and CSF brain injury markers might aid in the understanding of both therapeutic and adverse effects of these drugs.     

Chiasmapexy for secondary empty sella syndrome: diagnostic and therapeutic considerations

Pituitary - Secondary empty sella syndrome (SESS) following pituitary surgery remains a diagnostic and therapeutic challenge. The aim of this study was to specify the diagnostic criteria, surgical...