Compact homogeneous Leviflat CR-manifolds

We consider compact Leviflat homogeneous Cauchy–Riemann (CR) manifolds. In this setting, the Levi-foliation exists and we show that all its leaves are homogeneous and biholomorphic. We analyze separately the structure of orbits in complex projective spaces and parallelizable homogeneous CR-manifolds in our context and then combine the projective and parallelizable cases. In codimensions one and two, we also give a classification.

Ischemic preconditioning and liver tolerance to warm or cold ischemia: experimental studies in large animals

BACKGROUND

In the rodent, ischemic preconditioning (IPC) has been shown to improve the tolerance of the liver to ischemia-reperfusion under normothermic or hypothermic conditions. The aim of the present study was to test this hypothesis in a dog model, which may be more relevant to the human.

METHODS

Beagle dogs were used in two distinct animal models of hepatic warm ischemia and orthotopic liver transplantation (hypothermic ischemia). IPC consisted of 10 minutes of ischemia followed by 10 minutes of reperfusion. In the first model, livers were exposed to 55 minutes prolonged warm ischemia and reperfused for 3 days (n = 6). In the second model, livers were retrieved and preserved for 48 hours at 4 degrees C in University of Wisconsin solution, transplanted, and reperfused without immunosuppression for 7 days (n = 5). In each model, nonpreconditioned animals served as controls (n = 5 in each group). Also, isolated dog hepatocytes were subjected to warm and cold storage ischemia-reperfusion to model the animal transplant studies using IPC.

RESULTS

In the first model (warm ischemia), IPC significantly decreased serum aminotransferase activity at 6 and 24 hours post-reperfusion. After 1 hour of reperfusion, preconditioned livers contained more adenosine triphosphate and produced more bile and less myeloperoxidase activity (neutrophils) relative to controls. In the second model (hypothermic preservation), IPC was not protective. Finally, IPC significantly attenuated hepatocyte cell death after cold storage and warm reperfusion in vitro.

CONCLUSIONS

IPC is effective in large animals for protecting the liver against warm ischemia-reperfusion injury but not injury associated with cold ischemia and reperfusion (preservation injury). However, the IPC effect observed in isolated hepatocytes suggests that preconditioning for preservation is theoretically possible.

Loss of endothelium-dependent relaxation in abdominal aorta preserved in a co-storage system

The potentially detrimental influence of parenchymal cells on endothelial function during preservation in UW solution was examined by co-storage of rat abdominal aortic rings with isolated liver cells. Cold storage of rings in UW solution alone for up to 96 h had no effect on the response to acetylcholine, though constriction was progressively lost. Co-storage of rings with liver cells resulted in no loss of sodium nitroprusside response, but the relaxation response to acetylcholine was reduced. The loss of acetylcholine response could not be attributed to Kupffer cells, the lowering of pH, oxygen depletion, or the loss of constriction. A similar loss of endothelial function was observed in rings stored in pieces of liver, kidney or heart. We conclude that parenchymal cells exude factors during preservation by cold storage which reversibly inhibit vascular NO production. These factors could significantly impair whole organ function on reperfusion.

The effects of donor brain death on renal function and arachidonic acid metabolism in a large animal model of hypothermic preservation injury

BACKGROUND

Donor brain death (BD) has been implicated as a risk factor for the poor performance of kidneys after transplantation in small but not large animal models. This study determined the effects of donor BD on renal function and lipid mediator metabolism in a large animal model of renal hypothermic preservation injury.

METHODS

Adult beagle donors were subjected to explosive BD for 16 hr. After BD, the kidneys were removed, cold stored for 24 hr in cold University of Wisconsin solution, and allotransplanted into recipient dogs for either 4 hr (group 1) or 7 days (group 2). Controls for both groups consisted of kidneys obtained from living donors. Renal allograft function and tissue arachidonic acid (AA) metabolism were determined after reperfusion.

RESULTS

Short-term renal function after transplantation was generally unaffected by BD. Renal blood flow decreased after reperfusion but was not altered during the 16-hr BD period. Neutrophil infiltration significantly increased in kidneys from brain-dead donors before storage and after 4 hr of reperfusion. Renal cortex and medulla AA metabolism were not significantly affected by BD after short-term reperfusion except when thiol-ether leukotrienes (LTC(4)/D(4)/E(4)) were increased with BD. Serum creatinine was elevated during 7 days, but, surprisingly, BD significantly attenuated this injury.

CONCLUSION

BD in large mammals does not significantly affect renal allograft function or AA metabolism after transplantation. The role of BD in human renal preservation injury and inflammation should be reevaluated.

Teaching senior nurses how to teach communication skills in oncology

Many nurses acknowledge that their nursing practice is hampered by inadequate teaching about communication skills during their nursing education. Ineffective communication has negative effects on patient care and causes stress when nurses interact with each other, with medical colleagues, with patients and their relatives. Many senior nurses teach junior staff about communication and feel uncertain about their competence to do so despite recognition of its importance. This article reports data from a training initiative endorsed by the Royal College of Nursing in the United Kingdom (UK) aimed at helping senior nurses to identify their personal strengths and weaknesses when communicating, learn new teaching methods and encourage new teaching initiatives. A residential 2-day course, based on learner-centered methods was employed. One hundred and twenty nine nurses from UK cancer centers worked on personal communication problems via group discussions, video demonstrations, small group teaching exercises and role-plays with professional actors. Post-course, participants reported significantly greater confidence in handling 14 common communication problem areas in cancer (p < .0001) and in 8 different areas of teaching. Participants were very enthusiastic about the course overall and especially valued the training approach and teaching materials provided. Three months post-course 91% reported changing their own teaching practice and 85% had initiated new communication skills teaching.

A novel endothelial cell-based gene therapy platform for the in vivo delivery of apolipoprotein E

A major focus in gene therapy has been the use of recombinant viruses to deliver genes in vivo. Although this approach shows much promise, there are many safety concerns associated with the use of viral materials in the treatment of human diseases. Our alternative cell-based gene therapy approach utilizes endothelial cells (Pro 175) isolated from the murine embryonic yolk sac. These endothelial cells were evaluated for their potential use in gene therapy as a gene delivery platform. As a test model, we used these cells to deliver apolipoprotein E (apoE) in the murine apoE knockout atherosclerosis model. The lack of apoE protein in these animals results in high levels of serum cholesterol and formation of severe aortic plaques and lesions at a young age. After transplantation of the apoE secreting Pro 175 endothelial cells into apoE-deficient mice, serum cholesterol levels were measured at 2 week intervals. During the 3 months after the initiation of these experiments, levels of cholesterol in the animals having received the apoE secreting endothelial cells were statistically lower compared with the levels of age-matched controls having received non-secreting endothelial cells. Concomitant with cholesterol reduction, atherosclerotic aortic plaques were noticeably reduced in the experimental apoE+ animals. These results highlight the potential of these unique endothelial cells as an efficient delivery platform for somatic gene therapy.

Role of endothelium in the control of mouse yolk sac stem cell differentiation

Studies in our laboratory have shown that as early as day 8.5 of development, mouse yolk sac cells can generate T cells when placed in a thymic microenvironment. At this stage, yolk sac cells can also differentiate into myeloid cells in vitro. B cell differentiation in vitro was achieved with day 9 yolk sac by providing a bone marrow stromal feeder layer. We have now established endothelial cell lines and clones from yolk sacs of day 8-12 mouse embryos. These vary in their ability to support stem cell maintenance and differentiation. Our principal work has been carried out with day 12 cloned endothelial cell lines. One clone supported the > 100 fold expansion of yolk sac hematopoietic stem cells that subsequently could generate B cells, T cells and myeloid cells both in vitro and in vivo. Preliminary experiments with endothelial cells from younger embryos are also described.

Emetine myopathy in a patient with an eating disorder

OBJECTIVE

To alert physicians to the dangers of a readily available, non-prescription drug by describing the clinical and pathological features of myopathy due to chronic poisoning with ipecac syrup in a patient with an eating disorder.

CLINICAL FEATURES

A 27-year-old woman presented in 1991 with a right foot drop, followed a few months later by progressive severe neck and limb weakness associated with dysphagia, faecal incontinence and diffuse body ache. It emerged that she had been consuming increasing quantities of ipecac syrup (up to 200 mL per week) for three months to induce vomiting and weight loss. The serum creatine kinase activity was slightly elevated and electromyographic examination results were in keeping with a necrotising proximal myopathic process. Muscle biopsy showed vacuolar degeneration with myofibrilolysis and fine cytoplasmic body formation, consistent with a diagnosis of emetine myopathy.

INTERVENTION AND OUTCOME

The patient was advised to stop taking ipecac and observed for the next few months. The symptoms resolved gradually and strength returned to normal in four months.

CONCLUSION

Chronic emetine toxicity, with its potentially catastrophic consequences, should be remembered in the evaluation of neuromuscular symptoms in young women, in whom eating disorders are common and often unrecognised.

A positive coping strategy. Humour in the oncology setting

Humour is an integral part of most positive human relationships, and does much to bring people closer together. Used sensitively and tactfully, it has much to offer patients and nurses in an oncology setting.

Progression from MERRF to MELAS phenotype in a patient with combined respiratory complex I and IV deficiencies

Identical twins developed myoclonic epilepsy in their teens. One twin remained mildly affected but the other went on to develop sensorineural deafness and ataxia with lactic acidosis and ragged red fibres leading to a diagnosis of mitochondrial encephalopathy. Multiple stroke-like episodes with hemiparesis followed, indicating progression from a MERRF to a MELAS phenotype. Biochemical studies revealed a severe deficiency of mitochondrial NADH-ubiquinone reductase and a moderate deficiency of cytochrome aa3. Western immunoblotting experiments using polyclonal antibodies raised against human placental cytochrome oxidase identified a similar profile of bands to those seen in controls, supporting the view that cytochrome aa3 deficiency in this case may be a secondary consequence of a failure of assembly related to a severe proximal respiratory chain defect.

Nuclear transplantation in bovine embryos

This study was conducted to develop a method for transplanting nuclei in bovine embryos and to test the development of several stages of donor nuclei transplanted to enucleated pronuclear recipient embryos. Pronuclear embryos were centrifuged to reveal nuclei. Nuclei were removed without penetrating the plasma membrane as membrane-bound karyoplasts, and were inserted into enucleated zygotes by electrically induced cell fusion. The highest rate of fusion (79%) occurred in Zimmerman Cell Fusion medium at 100 V for 20 to 40 microseconds with the fusion membranes oriented parallel to the electrodes. The effect of nuclear transplantation on development was tested in pronuclear embryos in which nuclei were removed and reinserted and the embryos were then transferred to sheep oviducts for 5 d. Of the intact nuclear transplant embryos recovered, 5/29 (17%) developed to morulae or blastocysts compared with 11/30 (37%) of the non-manipulated embryos. Two nuclear transplant embryos were transferred to a recipient cow, and both developed to normal offspring. When nuclei from two-, four-, or eight-cell embryos were transplanted to pronuclear recipient embryos, no development was observed.

Nuclear transplantation in mouse embryos: assessment of recipient cell stage

Enucleated zygotes were compared with enucleated two-cell embryos as recipients for donor nuclei from eight-cell embryos. Only one or two cleavage divisions were observed when eight-cell nuclei were transplanted to enucleated zygotes. Development of enucleated two-cell embryos containing a transplanted eight-cell nucleus was appreciably better with 51% (45/89) of the embryos forming blastocysts in vitro and 42% (25/60) initiating implantation. Of these, eleven implantation sites on Day 10 of gestation were examined histologically and two contained normally developing embryos. No development was observed beyond Day 12 of gestation. These observations indicate that a major transition occurs between the zygote and two-cell stage that results in the two-cell recipient being more compatible with the eight-cell nucleus than with the zygote.

Comparison of enteric-coated levodopa with levodopa-carbidopa combination. A double-blind crossover trial

Twenty-seven patients with idiopathic Parkinson's disease completed a double-blind crossover trial which compared enteric-coated levodopa (Prodopa) with levodopa-carbidopa combination (Sinemet). It was easy to stabilize the patients' condition with either drug, and the dose-sparing effect both of the enteric-coated preparation, and of the levodopa-carbidopa combination was again noted. At the dosages used, the levodopa-carbidopa combination was objectively shown to be more effective in 71% of the patients investigated, although there was no clear personal preference for either preparation when patients compared the two parts of the trial. Both drugs play a valuable role in the treatment of Parkinson's disease.

Epilepsy

Epilepsy is a common disorder affecting approximately one in every two hundred people, from all walks of life, and presenting in addition to the seizure disorder itself, varying social, psychological and economic problems. A simple classification of epilepsy is described, and the concept of 'seizure threshold' introduced. Having diagnosed epilepsy, the need for investigation to separate the symptomatic epilepsies from idiopathic epilepsy is stressed. Accurate diagnosis of seizure type ensures that optimal therapy can be offered. The various drugs used to control epilepsy are discussed, and comments on the general management of the patient are offered.

Bromocriptine in lieu of levodopa for Parkinson's disease

Thirteen patients with Parkinson's disease, whose disability was increasing and on long-term levodopa therapy (both with and without carbidopa), had the levodopa fully replaced by bromocriptine. At three months, eight of the 13 patients (62%) were less disabled on bromocriptine and none became worse. The present indications for the use of bromocriptine are discussed.

Epilepsy

Epilepsy is a common disorder affecting approximately one in every two hundred people, from all walks of life, and presenting in addition to the seizure disorder itself, varying social, psychological and economic problems. A simple classification of epilepsy is described, and the concept of 'seizure threshold' introduced. Having diagnosed epilepsy, the need for investigation to separate the symptomatic epilepsies from idiopathic epilepsy is stressed. Accurate diagnosis of seizure type ensures that optimal therapy can be offered. The various drugs used to control epilepsy are discussed, and comments on the general management of the patient are offered.

Enteric-coated L-dopa (prodopa). A new approach to L-dopa therapy in Parkinson's disease

Seventeen patients treated for a mean period of 9-4 months with an enteric-coated form of L-dopa (Prodopa), obtained the usual spectrum of benefit as from conventional L-dopa. There was a significant dose-sparing effect with the use of the enteric-coated prepartion of the order of 40% to 50%, whilst reducing gastrointestinal side effects to a minimum, at the same time as achieving optimal clinicl benefit. Enteric-coated L-dopa appears to be a useful and welcome addition to the therapeutic armamentarium for Parkinson's disease.