Synaptic efficacy during repetitive activation of excitatory inputs in primate dorsolateral prefrontal cortex

Neurons in the monkey dorsolateral prefrontal cortex (DLPFC) fire persistently during the delay period of working memory tasks. To determine how repetitive firing affects the efficacy of synaptic inputs to DLPFC layer 3 neurons, we examined the effects of repetitive presynaptic stimulation on the amplitude and temporal summation of EPSPs. Recordings were obtained in monkey DLPFC brain slices from regular spiking (RS) pyramidal cells and two types of interneurons, fast spiking (FS) and adapting non-pyramidal (ANP) cells. Repetitive stimulation of presynaptic axons in layer 3 caused EPSP depression in RS and FS neurons, but EPSP facilitation in ANP cells. A shorter EPSP duration produced weaker temporal summation in FS neurons compared to the other cell classes. Thus, due to the combined effects of dynamic changes in EPSP amplitude and differences in temporal summation, the effect of a presynaptic spike train differed according to the postsynaptic cell class. Similar results were obtained when recording unitary EPSPs evoked in connected pairs of presynaptic RS pyramidal cells and postsynaptic RS, FS or ANP neurons. In addition, similar differences in the efficacy of sustained inputs among cell classes were observed when delay-related firing was reproduced in vitro by stimulating inputs with the timing of spike trains recorded from the DLPFC of monkeys performing a delayed-response task. We suggest that the transition from baseline firing rates to higher frequency delay-related firing may lead to the differential activation of distinct cell populations, with corresponding significant effects on the patterns of activity in local prefrontal circuits.     

Epilepsy Care in the World: results of an ILAE/IBE/WHO Global Campaign Against Epilepsy survey

PURPOSE: Information about existing resources available within the countries to tackle the huge medical, social, and economic burden caused by epilepsy is lacking. To fill this information gap, a survey of country resources available for epilepsy care was conducted within the framework of the ILAE/IBE/WHO Global Campaign Against Epilepsy. METHODS: The study represents a major collaborative effort involving the World Health Organization (WHO), the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE). RESULTS: Data were collected from 160 countries representing 97.5% of the world population. The information included availability, role, and involvement of professional and patient associations for epilepsy, epilepsy treatment and services including antiepileptic drugs, human resources involved in epilepsy care, teaching in epileptology, disability benefits, and problems encountered by people with epilepsy and health professionals involved in epilepsy care. The data confirm that epilepsy care is grossly inadequate compared with the needs in most countries. In addition, large inequities exist across regions and income groups of countries, with low-income countries having extremely meager resources. Complete results of this survey can be found in the Atlas: Epilepsy Care in the World. CONCLUSIONS: The data reinforce the need for urgent, substantial, and systematic action to enhance resources for epilepsy care, especially in low-income countries.     

Melatonin in mood disorders.

The cyclic nature of depressive illness, the diurnal variations in its symptomatology and the existence of disturbed sleep-wake and core body temperature rhythms, all suggest that dysfunction of the circadian time keeping system may underlie the pathophysiology of depression. As a rhythm-regulating factor, the study of melatonin in various depressive illnesses has gained attention. Melatonin can be both a 'state marker' and a 'trait marker' of mood disorders. Measurement of melatonin either in saliva or plasma, or of its main metabolite 6-sulfatoxymelatonin in urine, have documented significant alterations in melatonin secretion in depressive patients during the acute phase of illness. Not only the levels but also the timing of melatonin secretion is altered in bipolar affective disorder and in patients with seasonal affective disorder (SAD). A phase delay of melatonin secretion takes place in SAD, as well as changes in the onset, duration and offset of melatonin secretion. Bright light treatment, that suppresses melatonin production, is effective in treating bipolar affective disorder and SAD, winter type. This review discusses the role of melatonin in the pathophysiology of bipolar disorder and SAD.     

Osteocapsular debridement for elbow arthritis

Open capsular debridement is an excellent option for the treatment of elbow arthritis. This technique is particularly indicated in a patient population physiologically younger than 60 years. Given the young age and high functional demand of patients with primary osteoarthritis of the elbow, prosthetic replacement is generally not recommended. Open capsular debridement preserves the native joint and thus does not inherently require permanent activity modification as does replacement arthroplasty.     

Apoptosis and proliferation of cultured mesangial cells isolated from kidneys of rosiglitazone-treated pregnant diabetic rats.

BACKGROUND: The peroxisome proliferator activating nuclear receptors (PPAR) are activated in the context of inflammation, diabetes or normal pregnancy. Renal mesangial cells express PPAR-gamma which upon activation are capable of exerting anti-inflammatory effects. We investigated the effect of in vivo treatment by rosiglitazone on angiotensin II (A-II) stimulated manifestations of inflammation in cultured renal mesangial cells, such as proliferation, apoptosis, TGF-beta1 production and nuclear factor kappaB (NF-kappaB) activation, in the situation of pregnancies, complicated or not with diabetes. METHODS: Mesangial cells were isolated from the following groups, receiving or not 5 mg/kg rosiglitazone for 20 days: normal controls, normal pregnant rats, those with streptozotocine induced diabetes and pregnant diabetic rats. Proliferation was assessed by 3H-thymidine incorporation. Apoptosis was evaluated by TUNEL assay. AT-1/AT-2 receptor density was assessed by 125I-AT-2 labelling, TGF-beta and NF-kappaB by specific ELISAs. RESULTS: Rosiglitazone pretreatment resulted in significantly decreased proliferation, apoptosis and reduced responsiveness to A-II stimulation in cultures from controls, pregnant rats and non-pregnant diabetic animals. In the pregnant diabetic group which received rosiglitazone prior to sacrifice, responsiveness to A-II was completely blunted. Moderate attenuation of TGF-beta synthesis and significant decrease in the levels of NF-kappaB in mesangial cell nuclei were observed in all rosiglitazone treated groups. CONCLUSIONS: PPAR-gamma activation by rosiglitazone resulted in decreased manifestation of inflammatory hallmarks, including inhibition of mesangial cell proliferation, downregulation of apoptosis and blunted responsiveness to A-II. These anti-inflammatory renoprotective effects were maximally expressed in cultures from pregnant diabetic animals. The therapeutic relevance of these observations is a matter of further investigations.     

Spinal cord ischemia following thoracotomy without epidural anesthesia

PURPOSE: Paraplegia is an uncommon yet devastating complication following thoracotomy, usually caused by compression or ischemia of the spinal cord. Ischemia without compression may be a result of global ischemia, vascular injury and other causes. Epidural anesthesia has been implicated as a major cause. This report highlights the fact that perioperative cord ischemia and paraplegia may be unrelated to epidural intervention. CLINICAL FEATURES: A 71-yr-old woman was admitted for a left upper lobectomy for resection of a non-small cell carcinoma of the lung. The patient refused epidural catheter placement and underwent a left T5-6 thoracotomy under general anesthesia. During surgery, she was hemodynamically stable and good oxygen saturation was maintained. Several hours following surgery the patient complained of loss of sensation in her legs. Neurological examination disclosed a complete motor and sensory block at the T5-6 level. Magnetic resonance imaging (MRI) revealed spinal cord ischemia. The patient received iv steroid treatment, but remained paraplegic. Five months following the surgery there was only partial improvement in her motor symptoms. A follow-up MRI study was consistent with a diagnosis of spinal cord ischemia. CONCLUSION: In this case of paraplegia following thoracic surgery for lung resection, epidural anesthesia/analgesia was not used. The MRI demonstrated evidence of spinal cord ischemia, and no evidence of cord compression. This case highlights that etiologies other than epidural intervention, such as injury to the spinal segmental arteries during thoracotomy, should be considered as potential causes of cord ischemia and resultant paraplegia in this surgical population.     

Results of Coronary Artery Bypass Grafting in Myocardial Bridging of Left Anterior Descending Artery

Background

We aimed to evaluate the graft patency rate following coronary artery bypass grafting (CABG) to the left anterior descending artery (LAD) with proximal myocardial bridging (MB). While MB is generally a benign coronary abnormality, ischemia, stunning, and sudden death have been reported. In symptomatic patients with proximal LAD systolic compression of >50%, positive for ischemic noninvasive testing and noneffective optimal medical therapy, coronary intervention could be indicated. Few studies of CABG in myocardial bridging have been reported. The influence of high flow in coronaries with MB on graft patency is cause for concern.

Methods

We retrospectively studied 39 patients operated on for isolated MB of proximal LAD with >50% systolic compression. All patients were severely symptomatic despite optimal medical therapy and positive noninvasive tests for myocardial ischemia. CABG was performed through the midsternotomy with cardiopulmonary bypass and cardioplegia. Patients were divided into two groups: in 20 patients, LAD was bypassed with left internal mammary artery (LIMA) (Group 1) and in 19 patients with saphenous vein graft (SVG) (Group 2). All patients underwent follow‐up coronary angiography.

Results

Demographics and degree of systolic compression of the LAD were similar in both groups. There was no mortality or major morbidity. Freedom from angina was 68% in Group 1 and 94% in Group 2 at 18 months postoperatively (p = 0.58). Twelve LIMA grafts and three SVGs were found occluded (p = 0.002).

Conclusions

LIMA patency in myocardial bridging of the LAD can be low. SVGs should be considered in cases of CABG for myocardial bridging. doi: 10.1111/jocs.12101 (J Card Surg 2013;28:218–221)