Identification and Quantification of Oligodendrocyte Precursor Cells in Multiple System Atrophy,Progressive Supranuclear Palsy and Parkinson's Disease

Multiple system atrophy is a neurodegenerative disorder characterized pathologically by abnormal accumulations of α‐synuclein in the cytoplasm of oligodendrocytes, which are termed glial cytoplasmic inclusions (GCIs). Oligodendrocytes are responsible for myelinating axons and providing neurotrophic support, but in MSA, myelin loss, axonal loss and gliosis are consistent features suggesting that GCIs play a central role in disease pathogenesis. Oligodendroglial, myelin and axonal degeneration are also features of multiple sclerosis (MS) in which recent studies have highlighted the robust remyelination capacity of the central nervous system (CNS). The cells responsible for remyelination are called oligodendroglial precursor cells (OPCs). In this study, we investigated the role of OPCs in the pathogenesis of MSA and progressive supranuclear palsy (PSP), a neurodegenerative disease in which neuropathological changes include oligodendroglial inclusions composed of microtubule‐associated protein tau. Despite the lability of OPC‐specific antigens, we successfully identified OPCs and demonstrated that tau and α‐synuclein do not accumulate in OPCs. We also showed that the density of OPCs was increased in a white matter region of the MSA brain, which is also severely affected by GCIs and myelin degeneration. These findings raise the possibility that OPCs could be available to repair disease‐associated damage in MSA, consistent with their biological function.     

Antibodies to cannabinoid type 1 receptor co‐react with stomatin‐like protein 2 in mouse brain mitochondria

Anti‐cannabinoid type 1 receptor (CB₁) polyclonal antibodies are widely used to detect the presence of CB₁ in a variety of brain cells and their organelles, including neuronal mitochondria. Surprisingly, we found that anti‐CB₁ sera, in parallel with CB₁, also recognize the mitochondrial protein stomatin‐like protein 2. In addition, we show that the previously reported effect of synthetic cannabinoid WIN 55,212‐2 on mitochondrial complex III respiration is not detectable in purified mitochondrial preparations. Thus, our study indicates that a direct relationship between endocannabinoid signaling and mitochondrial functions in the cerebral cortex seems unlikely, and that caution should be taken interpreting findings obtained using anti‐CB₁ antibodies.     

Low CA1 spine synapse density is further reduced by castration in male non-human primates

The hippocampus plays a major role in learning and memory and its morphology and function are readily affected by gonadal hormones in female non-human primates. We sought to determine whether the gonads also affect pyramidal cell spine synapse density in the CA1 hippocampal area of male primates. Unbiased electron microscopic stereological calculations were performed to determine the volumetric density of pyramidal cell spine synapses and semiquantitative analyses on the surface density of glial fibrillary acidic protein-containing glia processes and the diameter of pyramidal cell apical dendrites in the CA1 area of intact and orchidectomized (1 month) St Kitts vervet monkeys (Chlorocebus aethiops sabaeus). The volumetric density (number of spine synapse/ micro m(3)) of spine synapses was significantly lower (40%) in the gonadectomized animals than in control monkeys; conversely, the density of glia processes was significantly higher (15%) and the diameter of dendritic shafts located in this area was also larger (30%) in the orchidectomized animals than in the controls. Strikingly, when compared to female values, intact male primates had lower spine synapse densities than either intact or ovariectomized females. Since the primate hippocampus is very similar to that of a human's, the present observations suggest that physiological levels of circulating androgen hormones are necessary to support normal spine synapse density in the CA1 stratum radiatum of human male hippocampus.     

The effect of trimodal prehabilitation on the physical and psychological health of patients undergoing colorectal surgery: a randomised clinical trial

Prehabilitation aims to increase the endurance capacity of patients who are awaiting major surgery. However, there are no studies investigating the implementation of this demanding and expensive intervention in low-income countries. This study aimed to assess the impact of a 4-week trimodal prehabilitation program on the physical and psychological health of patients waiting for colorectal surgery compared with a control group managed according to enhanced recovery after surgery principles supplemented by nutritional care. This study was a single-centre, randomised controlled trial. The primary outcome measures for the physical aspects were 6-minute walking distance (6MWD) and incentive spirometry, whereas the psychological elements were measured using the 36-item short form survey questionnaire and the hospital anxiety and depression score. In total, data from 149 patients were analysed (77 in the prehabilitation group and 72 in the control group). At the time of surgery, patients in the prehabilitation group had improved 6MWD and incentive spirometry compared with the control group (median (IQR [range]) percentage improvement 131% (112–173 [68–376]) vs. 107% (99–120 [63–163]); p < 0.001 and 113% (100–125 [75–200]) vs. 100% (100–112 [86–167]); p < 0.001 respectively). Patients in the prehabilitation group also had reduced anxiety scores compared with the control group (mean (SD) anxiety score (4 (3) vs. 5 (3) respectively; p = 0.032). However, these effects did not translate into improvements in postoperative mortality and morbidity, or a reduction in duration of hospital stay. Trimodal (physical, emotional and nutritional) prehabilitation is able to improve functional status as well as some parameters of emotional and physical well-being of patients waiting for colorectal surgery.     

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European Spine Journal - Depression, anxiety, catastrophising, and fear-avoidance beliefs are key "yellow flags" (YFs) that predict a poor outcome in back patients. Most surgeons...     

The pentylenetetrazole-induced activity in the hippocampus can be inhibited by the conversion of L-kynurenine to kynurenic acid: an in vitro study

The kynurenine pathway converts tryptophan into various compounds, including l-kynurenine, which in turn can be converted into the excitatory amino acid receptor antagonist kynurenic acid. The ionotropic glutamate receptors have been considered to be attractive targets for new anticonvulsants in neurological disorders such as epileptic seizure. This study was designed to examine the conversion of l-kynurenine to kynurenic acid and to investigate the effects of kynurenic acid on pentylenetetrazole-treated rat brain slices, and in parallel to draw attention to the fact that a well-designed in vitro model has many advantages in pharmacological screening. Schaffer collateral stimulation-evoked field EPSPs were recorded from area CA1 of rat hippocampal slices in vitro; drugs were bath-applied. Pretreatment with the kynurenic acid precursor l-kynurenine led to the elimination of the effect of pentylenetetrazole on hippocampal slices in vitro. N-Omega-nitro-l-arginine, which inhibits kynurenine aminotransferase I and II, abolished this neuroprotective effect.This study has furnished the first in vitro electrophysiological evidence that rat brain slices have the enzymatic capacity to convert exogenously administered l-kynurenine (16 μM) to kynurenic acid in an amount sufficient to protect them against pentylenetetrazole (1 mM)-induced hyperexcitability.     

Doppler echocardiography assessment of prosthetic heart valves

Transthoracic Doppler echocardiography is an accurate noninvasive method for the evaluation of prosthetic valve function. The flow characteristics and pressure gradients of normally functioning mechanical and bioprosthetic valves have been, in general established. Normal functioning mitral valve prostheses have a valve area > 1.8 cm² with the St. Jude valve having the largest effective valve area and normally functioning aortic prosthetic valves have a peak instantaneous gradient of < 45 mmHg, with the Starr-Edwards valves (Starr-Edwards, Irvine CA) showing the highest gradients. The incidence of minimal or mild regurgitation is approximately 15% to 30% in the mitral position and 25% to 50% in the aortic position, with the higher incidence of regurgitation seen with mechanical compared to bioprosthetic valves. Transthoracic Doppler echocardiography can accurately detect patients with prosthetic valvular stenosis. The presence of prosthetic aortic regurgitation can also generally be accurately assessed, except in the presence of both prosthetic aortic and mitral valves. Assessment of prosthetic mitral regurgitation remains limited due to significant attenuation of the ultrasound beam by the prosthesis and the frequent underestimation of severity of regurgitation. Other limitations of transthoracic studies include assessment of leaflet morphology, detection of vegetations and valve abscesses, and differentiation between valvular and paravalvular regurgitation.     

PCTs/health improvement. The object of the exercise

A study of six primary care trusts showed that those most successful in tackling health improvement had certain common characteristics. Strong board-level support and leadership, combined with development funding, were the most effective. Successful PCTs also showed a corporate recognition of local health and socio-economic inequalities.