Biomedical subjects
R Nelson
Publications and source records attributed to R Nelson.
[Thromboembolic risks and surgery for varicose veins].
The authors carried out a study on 53 patients operated on for varices with the object of determining the risk of postoperative thromboembolism. They tried to answer three questions : 1) What is the magnitude of the risk of thromboembolism after this kind of surgery? 2) What is the value of the different methods of detection available? 3) What attitude should be adopted towards therapy, not of thromboembolism as a complication, but of the threat of thromboembolism?
Action of long-chain fatty acids on protein kinase C activity: comparison of omega-6 and omega-3 fatty acids.
The results presented in this paper indicate that long chain free fatty acids have a dual modulatory effect on Protein Kinase C (PKC) activity purified from rat colon. Saturated (stearic) and monounsaturated (oleic) fatty acids are weak activators of PKC in the absence of phosphatidyl serine (PS) and diolein (DO), but have no significant effect on the PS/DO stimulated activity. Increasing the degree of unsaturation of the fatty acid, such as linolenic, arachidonic and eicosapentaenoic acids, also increases their stimulatory action toward unstimulated PKC, as well as their inhibition of PS/DO stimulated enzyme activity. Within this group of fatty acids there is no significant difference in the response of PKC toward omega-6 versus omega-3 type fatty acids. However, docosahexaenoic acid, a 22 carbon omega-3 polyunsaturated fatty acid found primarily in fish oil affected PKC differently from all other fatty acids studied. This compound was unable to stimulate dormant PKC activity, but was a highly potent inhibitor of PS/DO stimulated PKC. It is hypothesized that the inhibitory action of this omega-3 fatty acid may contribute to the protective role of fish oil consumption on colon tumorigenesis.
Cryptosporidium parvum: in vitro cultivation in Madin-Darby canine kidney cells.
To facilitate studies of the biology of Cryptosporidium parvum, we have developed an in vitro culture system using Madin-Darby canine kidney (MDCK) cells as the host cell. Oocysts or free sporozoites were incubated 37 degrees C with monolayers of MDCK cells in supplemented RPMI 1640 medium and the cells were examined at various time intervals after initiation of the culture. High rates of infection (up to 90% of MDCK cells) were achievable. Sequential development of trophozoites, meronts, microgametocytes, and macrogametocytes was observed over a 72-h period of culture. Between 72 and 96 h we observed formation of oocyst walls, but fully sporulated oocysts were not observed. This culture system provides access to both the asexual and sexual intracellular stages of C. parvum.
Effects of dietary fish oil and corn oil on protein kinase C distribution in the rat colon with and without 1,2 dimethylhydrazine treatment and in rat colonic adenocarcinoma.
The activity and subcellular distribution of Protein Kinase C (PKC) was determined in the colons of Sprague-Dawley rats that were fed either a low fat rat chow or rat chow supplemented with 17% corn oil (40% ingested calories as fat). Rats given the high fat diets were either given no carcinogen or treated prior to or subsequent to the initiation of the test diets with 1,2 dimethylhydrazine (DMH). Rats were sacrificed and PKC activity determined in the soluble and particulate fractions of the colonic tissue 13 weeks after the initiation of the diets or DMH treatment, which was before tumor induction. In addition several rats were maintained on their diets until colon tumor formation occurred and PKC activity determined in the colonic tumor and compared to age matched control colonic tissue. In the absence of DMH, fish oil and corn oil equally augmented PKC activity and decreased the ratio of soluble/particulate PKC. With DMH treatment, corn oil augmented PKC as above, but fish oil supplementation resulted in a pattern of PKC activity and distribution more typical of a low fat diet, particularly when fish oil supplementation preceded DMH treatment. PKC activity in DMH induced colonic carcinomas was markedly depressed regardless of the fat source in the diet, when compared to colonic tissue from a non-DMH treated age matched low fat control.
Foreign compound metabolism studies with human liver obtained as surgical waste. Relation to donor characteristics and effects of tissue storage.
An investigation has been conducted on the foreign compound-metabolizing activity of human liver collected fresh from surgery or at autopsy from cadavers 3 to 18 hr old, and the effects of low temperature storage on the foreign compound-metabolizing activity of fresh human liver. The enzyme activities studied were microsomal cytochrome P-450 content, biphenyl 4-hydroxylation, benzo-(a)pyrene metabolism, halothane reduction, and 4-hydroxybiphenyl UDP-glucuronosyl transferase, as well as cytosolic thiopurine methyltransferase, thermostable (TS) phenolsulfotransferase, thermolabile (TL) phenolsulfotransferase, and 5-fluorouracil dehydrogenase. Cadaver liver was a poor source of material for metabolism studies with the majority of the enzymes investigated. There was an 84% decrease in the yield of microsomal protein, a 64% decrease in cytochrome P-450 content per mg of microsomal protein, and a 36% decrease in the biphenyl 4-hydroxylase specific activity in human cadaver liver that was a few hours old. UDP-glucuronosyl transferase showed a 70% decrease, TS phenolsulfotransferase a 84% decrease, TL phenolsulfotransferase a 97% decrease, and thiopurine methyltransferase no significant change in specific activity. The loss of activity for many of these enzymes could be simulated by keeping fresh human liver at the temperature of the body after death. Surgical waste provided a good source of fresh, histologically normal, human liver for metabolism studies. Microsomal cytochrome P-450 content showed a significant increase with the age of the liver donor. Metabolism of benzo(a)pyrene to 3-hydroxybenzo(a)pyrene and benzo(a)pyrene-7,8- and -9,10-diols showed up to 136% higher rates in fresh liver microsomes from female donors.(ABSTRACT TRUNCATED AT 250 WORDS)
Computerized record maintenance system for clinical education.
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Anticoagulant-related intracranial haemorrhage.
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A format for surveying computer-related learning needs in health care settings.
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Continuing education through the world wide web.
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What's to be done with "bad" children?
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Recombinant human erythropoietin therapy for anemic cancer patients receiving cisplatin chemotherapy.
PURPOSE: To assess whether the administration of recombinant human erythropoietin (r-HuEPO) would increase the hematocrit, reduce the requirement for transfusion, and improve the quality of life in anemic cancer patients receiving myelosuppressive, cisplatin-based chemotherapy. PATIENTS AND METHODS: One hundred thirty-two anemic cancer patients receiving cyclic, cisplatin-containing, myelosuppressive chemotherapy were evaluated. Patients received either r-HuEPO (150 U/kg) or placebo, subcutaneously, three times a week for 3 months. Responses were assessed by measuring changes in hemoglobin/hematocrit, transfusion requirement, and quality of life. RESULTS: The mean hematocrit increased by 6.0 percentage points in the r-HuEPO group versus 1.3 in the placebo group. A decrease in transfusion requirement did not reach significance over all 3 months, but there was a significant reduction in the percentage of patients transfused in the second and third months (27% r-HuEPO vs. 56% placebo) and a trend toward reduction in the mean total number of units transfused (1.20 units r-HuEPO vs. 2.02 units placebo), suggesting a lag of 1 month before r-HuEPO can affect the transfusion requirement. Pretreatment serum erythropoietin levels were lower in responders than in nonresponders (73.5 IU/L and 86.3 IU/L means, respectively). However, the magnitude of this difference was not helpful in defining which patients were likely to respond. There was a significant improvement in overall quality of life between the two treatment arms in favor of the r-HuEPO-treated group. There were no significant adverse effects associated with r-HuEPO. CONCLUSIONS: r-HuEPO is safe and can cause a significant improvement in the hematocrit and quality of life of anemic cancer patients receiving myelosuppressive, cisplatin-based chemotherapy. After 1 month of r-HuEPO, there is also a reduction in transfusion requirement.
Learned and unlearned in the past year.
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Preparation for an online asynchronous university doctoral course. Lessons learned.
This article addresses the development of the initial course in the first completely online doctoral program in nursing. Synchronous and asynchronous methods of distance education were assessed. Planning focused at the university, school, and course levels. University planning involved the technical infrastructure, registration, student services, and library services. School planning examined administrative commitment and faculty commitment and willingness. Course planning focused on marketing, precourse information, time frame, modular design, planned interaction, and professor availability and support. Implementation issues centered on getting students connected, learning the software, changing instructional methods, and managing chats. Traditional methods of evaluating student learning and course evaluation were supplemented with the development of qualitative and quantitative tools to gather data for making administrative decisions. The Dean and faculty agreed that the internet was an effective method of delivering content in the initial Health Policy course. The Dean and faculty agreed to continue the PhD program online for one cohort and continue to evaluate student progress and faculty and student satisfaction.