The St. Jude experience

This paper covers our experience with the use of the St. Jude prosthetic heart valve from November 1979 through August 1983 in 91 patients operated on for aortic and mitral valve replacement. Nonfatal complications included hemorrhagic sequela due to anticoagulation, with an annual rate of 1 percent (1.4 percent per 100 patient years), thromboembolism with an annual rate of 0.8 percent (0.87 percent per 100 patient years), sternal infection 1 percent, operative cardiovascular accident 1 percent, and pericardial tamponade 1 percent.Operative mortality was 1 percent, early mortality (within 30 days) was 3 percent, and late mortality was 3 percent, with a total overall mortality of 7 percent. Excluding two patients who died from noncardiac causes, the overall mortality was 5 percent. The mortality rate per year was 2 percent. The survival rate 3.8 years postoperatively was 89 percent for mitral valve replacement patients and 93 percent for aortic valve replacement patients, for an overall 38 year survival rate of 92 percent. All patients were anticoagulated with warfarin. There were no instances of valve failure, replacement, or serious hemolysis. Eighty-three percent were active or working with a New York heart functional class I.In our experience, the complication rate with the St. Jude valve is as low or lower than that for any other mechanical prosthetic cardiac valve available in the world today.     

Threshold control of chaotic neural network

The chaotic neural network constructed with chaotic neurons exhibits rich dynamic behaviour with a nonperiodic associative memory. In the chaotic neural network, however, it is difficult to distinguish the stored patterns in the output patterns because of the chaotic state of the network. In order to apply the nonperiodic associative memory into information search, pattern recognition etc. it is necessary to control chaos in the chaotic neural network. We have studied the chaotic neural network with threshold activated coupling, which provides a controlled network with associative memory dynamics. The network converges to one of its stored patterns or/and reverse patterns which has the smallest Hamming distance from the initial state of the network. The range of the threshold applied to control the neurons in the network depends on the noise level in the initial pattern and decreases with the increase of noise. The chaos control in the chaotic neural network by threshold activated coupling at varying time interval provides controlled output patterns with different temporal periods which depend upon the control parameters.     

Regional expression of Bcl-2 mRNA and mitochondrial cytochrome c release after experimental brain injury in the rat

Regional levels of anti-apoptotic Bcl-2 mRNA and the cytosolic cytochrome c protein were measured after lateral fluid percussion (FP) brain injury in rats. Levels of Bcl-2 mRNA were significantly decreased in the injured left cortex (IC) and ipsilateral hippocampus (IH), but not in the contralateral right cortex (CC) and hippocampus (CH) after brain injury. Levels of Bcl-2 mRNA were significantly decreased as early as 2 h and stayed decreased as long as 48 h in the IC and IH after injury. Levels of the cytosolic cytochrome c protein were significantly increased in the IC and IH, but not in the CC and CH after brain injury. Levels of cytosolic cytochrome c were significantly increased in the IC at 30 min, 48 and 72 h, and in the IH at 2 h and as long as 72 h after injury. The increase of cytosolic cytochrome c suggests that the mitochondrial release of cytochrome is increased in the IC and IH after lateral FP brain injury. These data show that the reduction of anti-apoptotic Bcl-2 and increases of mitochondrial release of cytochrome c protein occur only in the IC and IH, regions which have been observed to undergo apoptosis and neuronal cell loss after lateral FP brain injury. Therefore, it is likely that the reduction of Bcl-2 and the increased cytochrome c protein in the cytosol contribute to the observed apoptosis and neuronal cell death in the IC and IH after lateral FP brain injury in rats.     

S1P1 receptor subtype inhibits demyelination and regulates chemokine release in cerebellar slice cultures

Sphingosine-1-phosphate receptors (S1PRs) are drug targets for the compound FTY720, which is the first oral therapy developed for treatment of relapsing-remitting multiple sclerosis. S1PRs play a variety of functional roles in the differentiation, proliferation, survival and/or migration of neurons and glia. In this study, rat organotypic cerebellar slice cultures were used to assess whether S1PRs play a role in demyelination induced by lysolecithin (LPC). The data demonstrated that FTY720 and SEW2871 (a S1P1R-specific agonist) inhibited LPC-induced demyelination as assessed by myelin basic protein (MBP) immunofluorescence. Treatment with both drugs for 48 h also induced an increase in S1P1R expression in astrocytes. Moreover, FTY720 and SEW2871 inhibited the release of several chemokines in conditions of LPC-induced demyelination, including LIX (CXCL5), MIP-1alpha, and MIP-3alpha. Taken together, the data suggest that activation of S1P1Rs prevents LPC-induced demyelination via a mechanism involving a reduction of chemotactic chemokine release. The study supports the concept that FTY720 attenuates demyelination by not only preventing S1PR-mediated T cell migration into the CNS but also by limiting cytokine communication between cells of the immune system and the CNS.     

The Prevalence and Timing of Obstetric Ultrasound in Victoria 1991–1992: a Population-based Study

Summary: A statewide study to ascertain the number of ultrasound scans received by women in pregnancy, to identify the proportion having a scan at 16 to 20 weeks' gestation, and to establish where the scan at 16 to 20 weeks was performed was carried out between January, 1991 and June, 1992 in Victoria. Additional data were collected by midwives and entered on the perinatal morbidity statistics form routinely completed for all births. Of 52,319 women providing responses, 3.1% did not have a scan. Of the remaining 96.9% who had a scan, 73.5% were scanned at 16 to 20 weeks'gestation. Predictors of not having a scan were maternal birthplace and higher parity: previous perinatal death(s), and attendance at nonteaching hospitals predicted the opposite. Predictors of being scanned were location of hospital (country), maternal birthplace, higher parity and maternal age (< 20 years). Substantial differences in frequency and timing were found between hospitals attended. Factors associated with the pattern of scanning are not readily explicable in terms of risk of malformations or women's choices.     

Analysis of nodal metastasis in malignancies of upper aerodigestive tract

A mass appearing in the neck can be a diagnostic challenge. The malignancies of upper aerodigestive tract are mostly squamous cell carcinoma and their metastasis remain largely confined to accessible neck areas permitting useful surgical management. In this study 30 patients were taken up with neck node metastasis. It was found that in supraglottic carcinoma even in no neck incidence of nodal metastasis was high. Even the retropharyngeal lymphnodes not involved in routine radical neck dissection were found to be involved in a few cases, which justifies the search for nodes in retropharyngeal area in routine radical neck dissection.     

The presentation and management of the nasal glioma

Nasal gliomata are rare and experience in management is therefore not widespread. Clinical details of 5 children with nasal gliomata are presented. In each case the glioma was excised by an external approach without the need for craniotomy. These cases demonstrate the variability of presenting features and problems in management. They illustrate a relatively conservative surgical approach to treatment which we consider to be safe and effective. The characteristics of these unusual neural malformations are reviewed, and the management is discussed.     

Perceived barriers to medical-error reporting: an exploratory investigation

Medical-error reporting is an essential component for patient safety enhancement. Unfortunately, medical errors are largely underreported across healthcare institutions. This problem can be attributed to different factors and barriers present at organizational and individual levels that ultimately prevent individuals from generating the report. This study explored the factors that affect medical-error reporting among physicians and nurses at a large academic medical center located in the midwest United States. A nominal group session was conducted to identify the most relevant factors that act as barriers for error reporting. These factors were then used to design a questionnaire that explored the likelihood of the factors to act as barriers and their likelihood to be modified. Using these two parameters, the results were analyzed and combined into a Factor Relevance Matrix. The matrix identifies the factors for which immediate actions should be undertaken to improve medical-error reporting (immediate action factors). It also identifies factors that require long-term strategies (long-term strategy factors) as well as factors that the organization should be aware of but that are of lower priority (awareness factors). The strategies outlined in this study may assist healthcare organizations in improving medical-error reporting, as part of the efforts toward patient-safety enhancement. Although factors affecting medical-error reporting may vary between different organizations, the process used in identifying the factors and the Factor Relevance Matrix developed in this study are easily adaptable to any organizational setting.