Neuroprotective effects of intramuscular ketamine in rabbit retinas after pars plana vitrectomy and silicone oil injection

PURPOSE: To investigate potential retinal neuroprotective effects of intramuscular ketamine in rabbits after pars plana vitrectomy (PPV) and intravitreal silicone oil injection (SOI). METHODS: Twelve New Zealand rabbits (weight, 2.0-2.5 kg) underwent PPV with SOI in the right eye. Postoperatively, six rabbits received a daily intramuscular injection of ketamine for 4 weeks (ketamine-operated eyes), and six rabbits received a daily intramuscular injection of saline (saline-operated eyes). The retina from the left eye of each rabbit served as a control (ketamine-control and saline-control eyes). The animals were euthanized at 4 weeks after surgery. Qualitative and quantitative analyses were performed using the Zeiss Axiophot microscope and KS 400 software. RESULTS: Qualitative analysis using light microscopy demonstrated more extensive edema and cell disorganization in saline-operated retinas than in ketamine-operated, ketamine-control, and saline-control retinas. Quantitatively, the cell densities (cell/mm) in the outer nuclear layer (ONL), inner nuclear layer (INL), and ganglion cell layer (GCL) in saline-operated retinas were significantly (P < 0.05) lower than those in these layers in ketamine-operated, ketamine-control, and saline-control retinas. The cell density in the ONL in saline-operated retinas was 52% lower than that in ketamine-operated retinas, 55% lower than that in ketamine-control retinas, and 56% lower than that in saline-control retinas. The cell density in the INL in saline-operated retinas was 44% lower than that in ketamine-operated retinas, 48% lower than that in ketamine-control retinas, and 49% lower than that in saline-control retinas. The cell density in the GCL in saline-operated retinas was 60% lower than that in ketamine-operated retinas, 64% lower than that in ketamine-control retinas, and 64% lower than that in saline-control retinas. CONCLUSION: PPV with SOI was associated with retinal cell death and disorganization in rabbit eyes. Intramuscular ketamine administration provided protection against these effects.     

Role of computed tomography in risk assessment for coronary heart disease

Coronary heart disease is the most common cause of death in Western countries, with a rising incidence in developing countries. It is part of the spectrum of cardiovascular diseases that have common end points of myocardial infarction, stroke and death. As these end points often occur suddenly and often in those with no known disease, identification of those people at high risk is important. Besides the known traditional risk factors, direct imaging of the calcified plaque as a marker for atherosclerotic disease has been extensively studied with electron beam computed tomography and now with multislice computed tomography. This review discusses the role of computed tomography in assessment of cardiovascular risk in both people with or without symptoms.     

Do Surface-Modifying Additive Circuits Reduce the Rate of Cerebral Microemboli During Cardiopulmonary Bypass?

The objective of this study was to determine if surface-modifying additive (SMA) cardiopulmonary bypass (CPB) circuits are associated with a lower rate of cerebral microemboli during CPB compared with standard circuits. In a 2 x 2 factorial design, patients undergoing coronary artery bypass graft surgery were randomized to SMA or standard CPB circuits (with and without methyl-prednisolone). Transcranial Doppler was used to detect high-intensity transient signals (HITS) in both middle cerebral arteries. HITS were counted from onset to end of CPB. Intervals of interest were as follows: period 1, from CPB onset to aortic cross-clamping; period 2, from aortic cross-clamping to immediately before de-clamping; period 3, from aortic declamping to before aortic side-clamping; period 4, from the application of the aortic side clamp to immediately before the release of the side clamp; period 5, from aortic side clamp release to the end of CPB. There were 14 patients in each circuit group. No significant differences were found on the partial and total counts of HITS (medians [25th, 75th percentile]) between patients exposed to standard (total count: 228 HITS [174, 2801) and SMA circuits (total count: 156 HITS [104, 356]; p = .427). The median of the sum of HITS per patient associated with perfusionist interventions was not different between both circuit groups (standard: 17 HITS [7, 80]; SMA: 43 HITS [13, 168]; p = .085). This study, with a sample size of 28 patients, indicates that it is unlikely to find any difference in the count of HITS during CPB that is greater than 117 HITS between the two CPB circuits. Moreover, our findings emphasize the relevance of minimizing additional sources of cerebral microembolization during CPB that are not directly related to the biocompatible nature of the SMA CPB circuit.     

Oestrogen receptors and the response to endocrine therapy in advanced breast cancer.

The relationship between oestrogen-receptor protein (ER) content of the tumour and the response to endocrine therapy was determined in 119 patients, in a collaborative prospective study. Twenty-eight of the 80 patients with measurable ER responded to treatment according to UICC criteria, compared with only 3/39 without ER. It was found that site of biopsy did not influence the result, but tumour content of the tissue sample was significantly related to the presence of receptors. The organizational problems of such a study are discussed.     

High resolution computed tomographic assessment of asbestosis and cryptogenic fibrosing alveolitis: a comparative study.

BACKGROUND: The aim of this study was to compare the distribution and configuration of lung opacities in patients with cryptogenic fibrosing alveolitis and asbestosis by high resolution computed tomography. METHODS: Eighteen patients with cryptogenic fibrosing alveolitis and 24 with asbestosis were studied. Two independent observers assessed the type and distributions of opacities in the upper, middle, and lower zones of the computed tomogram. RESULTS: Upper zone fibrosis occurred in 10 of the 18 patients with cryptogenic fibrosing alveolitis and in six of the 24 patients with asbestosis. A specific pattern in which fibrosis was distributed posteriorly in the lower zones, laterally in the middle zones, and anteriorly in the upper zones was seen in 11 patients with cryptogenic fibrosing alveolitis and in four with asbestosis. Band like intrapulmonary opacities, often merging with the pleura, were seen in 19 patients with asbestosis but in only two with cryptogenic fibrosing alveolitis. Areas with a reticular pattern and a confluent or ground glass pattern were the commonest features of cryptogenic fibrosing alveolitis (15 and 14 patients respectively) but were uncommon in asbestosis (four and three patients). Pleural thickening or plaques were seen in 21 patients with asbestosis and in none with cryptogenic fibrosing alveolitis. CONCLUSION: Apart from showing pleural disease high resolution computed tomography showed that confluent (ground glass) opacities are common in cryptogenic fibrosing alveolitis and rare in asbestosis whereas thick, band like opacities are common in asbestosis and rare in cryptogenic fibrosing alveolitis.     

Parameterization of transcranial magnetic stimulation

A recent study (Di Lazzaro et al. J Neurophysiol 105: 2150-2156, 2011) describes the findings from a rigorous comparison on the effects of several popular variations of transcranial magnetic stimulation (TMS) protocols. The results demonstrate that excitatory and inhibitory neural networks may be independently modulated based on TMS protocol selection. Moreover, the within-group replication of multiple between-group experiments suggests that independent evaluations of TMS parameters will continue to inform and guide future TMS research.