[Human rights, maternal mortality and reproductive health].
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Cause of Death↗
Biomedical subjects
R J Cook
Publications and source records attributed to R J Cook.
Mifepristone (RU 486)--an abortifacient to prevent abortion?
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Abortion, Induced↗
The natural history of asymptomatic urolithiasis.
An inception cohort of 107 patients was reviewed to establish the natural history of asymptomatic urolithiasis. With an over-all mean followup of 31.6 months, 73 patients (68.2%) remained asymptomatic and were censored at the time of the last clinical visit. A symptomatic event developed in 34 patients (31.8%). Spontaneous passage occurred in 16 patients (15.0%), endoureteral removal was done in 6 (5.6%), percutaneous nephrostolithotomy was done in 3 (2.8%) and 9 (8.4%) were referred for therapeutic lithotripsy. Cumulative 5-year probability of a symptomatic event developing was 48.5%. A linear association was identified between the development of a symptomatic event and the number of previous stones as well as the number of asymptomatic stones at identification. A significant burden of illness is associated with an expectant strategy as an approach to asymptomatic urolithiasis. Of the patients who had a symptomatic event 47% had spontaneous stone passage, while 26.5% required urological intervention and 26.5% were referred for therapeutic lithotripsy. Prophylactic extracorporeal shock wave lithotripsy, although often advocated, has associated risks and is not always a benign procedure. A randomized controlled trial is required to evaluate properly the role of prophylactic lithotripsy versus an expectant strategy.
Adult↗
Canadian Hemodialysis Morbidity Study.
The objective of this study was to determine the probabilities of specific morbid events or death among patients with end-stage renal disease (ESRD) treated by hemodialysis. A prospective cohort study was performed between March 1988 and September 1989 in 18 hemodialysis centers in 13 Canadian cities, representing about one third of the hemodialysis population in Canada. The inception cohort consisted of 496 patients entering hemodialysis who had survived 1 month. The few new hemodialysis patients who received erythropoietin (EPO) in the last 3 months of the study were excluded. Survival curves were compared using the Cox proportional hazards regression model. Older age and history of cardiovascular disease were independently associated with a greater probability of death. Age and history of cardiovascular disease were also associated with a greater probability of nonfatal circulatory events (myocardial infarction, angina requiring hospitalization, or stroke), while a serum albumin level less than or equal to 30 g/L (3.0 g dL) was associated with an increased probability of pulmonary edema. The probability of surviving 12 months without receiving a blood transfusion was 47.2% for males and 27.5% for females. The incidence of non-A, non-B hepatitis, as estimated by unexplained elevations in serum aspartate aminotransferase (AST) values, was not different between patients receiving and not receiving blood transfusions. The probability of hospitalization for any cause was greater for patients with grafts for vascular access than for those with fistulae, for those with a history of cardiovascular disease, for those with a serum albumin level less than or equal to 30 g/L, and for those with renal disease due to diabetes or vascular disease. Hospitalization due to circulatory disease was more likely among those with a history of cardiovascular disease and among those with a lower serum albumin level. Hospitalization for infectious disease was more likely among those with a lower serum albumin level and less likely among those with a fistula for vascular access. Among all patients receiving hemodialysis treatment for more than 6 months, there were 14.8 hospital days per year.(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
Antiprogestin drugs: ethical, legal and medical issues.
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Abortifacient Agents, Steroidal↗
Contribution of phenazine antibiotic biosynthesis to the ecological competence of fluorescent pseudomonads in soil habitats.
Phenazine antibiotics produced by Pseudomonas fluorescens 2-79 and Pseudomonas aureofaciens 30-84, previously shown to be the principal factors enabling these bacteria to suppress take-all of wheat caused by Gaeumannomyces graminis var. tritici, also contribute to the ecological competence of these strains in soil and in the rhizosphere of wheat. Strains 2-79 and 30-84, their Tn5 mutants defective in phenazine production (Phz-), or the mutant strains genetically restored for phenazine production (Phz+) were introduced into Thatuna silt loam (TSL) or TSL amended with G. graminis var. tritici. Soils were planted with three or five successive 20-day plant-harvest cycles of wheat. Population sizes of Phz- derivatives declined more rapidly than did population sizes of the corresponding parental or restored Phz+ strains. Antibiotic biosynthesis was particularly critical to survival of these strains during the fourth and fifth cycles of wheat in the presence of G. graminis var. tritici and during all five cycles of wheat in the absence of take-all. In pasteurized TSL, a Phz- derivative of strain 30-84 colonized the rhizosphere of wheat to the same extent that the parental strain did. The results indicate that production of phenazine antibiotics by strains 2-79 and 30-84 can contribute to the ecological competence of these strains and that the reduced survival of the Phz- strains is due to a diminished ability to compete with the resident microflora.
Anti-Bacterial Agents↗
Prevention of tachycardia with atenolol pretreatment for carotid endarterectomy under cervical plexus blockade.
A double-blind, randomised, controlled trial of forty patients was carried out to determine if oral atenolol pretreatment would reduce the incidence of tachycardia during carotid endarterectomy performed under cervical plexus block. Twenty patients received a placebo and twenty patients 50 mg of atenolol two hours prior to surgery. The superficial and deep cervical blocks were performed with 1.5% lignocaine containing 1:200,000 adrenaline. The patients were monitored with the V5 lead of the electrocardiogram and intra-arterial blood pressure. These measurements were recorded on a correctly calibrated paper recorder. Tachycardia (heart rate greater than 90 beats per minute for more than three minutes) occurred in thirteen patients in the placebo group and two patients in the atenolol group (P less than 0.01). There was no difference in the occurrence of bradycardia, hypotension or hypertension between the two groups. It is concluded that atenolol pretreatment is an effective method of reducing the incidence of tachycardia during carotid endarterectomy performed under cervical plexus blockade.
Aged↗
Isolation and characterization of cDNA clones for rat liver 10-formyltetrahydrofolate dehydrogenase.
We have isolated and characterized cDNA clones encoding rat liver cytosol 10-formyltetrahydrofolate dehydrogenase (EC 1.5.1.6). An open reading frame of 2706 base pairs encodes for 902 amino acids of Mr 99,015. The deduced amino acid sequence contains exact matches to the NH2-terminal sequence (28 residues) and the sequences of five peptides derived from cyanogen bromide cleavage of the purified protein. The amino acid sequence of 10-formyltetrahydrofolate dehydrogenase has three putative domains. The NH2-terminal sequence (residues 1-203) is 24-30% identical to phosphoribosylglycinamide formyltransferase (EC 2.1.2.2) from Bacillus subtilis (30%), Escherichia coli (24%), Drosophila melanogaster (24%), and human hepatoma HepG2 (27%). Residues 204-416 show no extensive homology to any known protein sequence. Sequence 417-900 is 46% (mean) identical to the sequences of a series of aldehyde dehydrogenase (NADP+) (EC 1.2.1.3). Intact 10-formyltetrahydrofolate dehydrogenase exhibits NADP-dependent aldehyde dehydrogenase activity. The sequence identity to phosphoribosylglycinamide formyltransferase is discussed, and a binding region for 10-formyltetrahydrofolate is proposed.
Amino Acid Sequence↗
Stress ulcer prophylaxis in the critically ill: a meta-analysis.
PURPOSE: To examine the differential effect of stress ulcer prophylaxis on overt bleeding, clinically important bleeding, and mortality in critically ill patients. DATA IDENTIFICATION: Computerized bibliographic search of published and unpublished research. STUDY SELECTION: Independent review of 168 articles identified 42 relevant randomized trials for inclusion. DATA ABSTRACTION: The validity, population, intervention, and outcomes of each trial were evaluated. RESULTS: Stress ulcer prophylaxis with antacids (odds ratio 0.40 [95% confidence interval (CI) 0.20 to 0.79]) or histamine-2-receptor antagonists (odds ratio 0.29 [95% CI 0.17 to 0.45]) decreases the incidence of overt gastrointestinal bleeding. Histamine-2-receptor antagonists are more effective than antacids at reducing overt hemorrhage (odds ratio 0.56 [95% CI 0.33 to 0.97]). A significant reduction in clinically important gastrointestinal hemorrhage is evident only with histamine-2-receptor antagonist therapy. There is a trend favoring antacids over sucralfate in the outcome of clinically important bleeding (odds ratio 0.65 [95% CI 0.16 to 2.49]); however, there are insufficient data to evaluate histamine-2-receptor antagonists versus sucralfate. No difference in mortality between treated and untreated patients was found. CONCLUSIONS: Overt gastrointestinal bleeding in critically ill patients is reduced by prophylaxis with antacids or histamine-2-receptor antagonists. Histamine-2-receptor antagonists are more effective than antacids at decreasing overt bleeding and are more effective than no treatment at reducing the incidence of clinically important bleeding. Mortality rates in the intensive care unit are not decreased by stress ulcer prophylaxis.
Critical Care↗
Response of the oral mucosa to denture wearing.
This paper reviews both past and current knowledge concerning the controversial subject of mucosal responses associated with denture wearing. The subject has been considered in terms of both gross clinical and histopathological changes arising from daily prosthesis use. Displacement of basal seat tissues during function has been discussed, along with denture-induced alterations of the local microfloral ecosystems. The influences of common drugs and therapeutic regimens such as ionizing radiation treatments have been considered, and as with all the fields discussed, have been related to clinical use and success of prostheses.
Dentures↗
Does combined epidural lignocaine and fentanyl provide better anaesthesia for ESWL than lignocaine alone?
The efficacy of epidural fentanyl combined with lignocaine 1.5% with adrenaline 1:200,000 was studied in a randomised, double-blind, controlled trial of two hundred patients undergoing extracorporeal shock wave lithotripsy with or without ancillary procedures. The quality of anaesthesia was assessed using linear analogue pain scores, the patient's impression, and the rate of intra-operative intervention by the anaesthetist. Postoperative symptomatology was also recorded. The only significant difference lay postoperatively in that the fentanyl-ancillary procedure sub-group had less pain approximately one hour postoperatively (P = 0.01). In the context of this study and in the presence of an adequate autonomic and somatic local anaesthetic blockade, the addition of epidural fentanyl does not appear to confer any significant advantage other than to enhance postoperative analgesia.
Anesthesia, Epidural↗
A comparison of several point estimators of the odds ratio in a single 2 x 2 contingency table.
The relative performance of the unconditioned maximum likelihood estimators (UMLEs), conditional MLEs (CMLEs), and Jewell-type estimators of the odds ratio (OR) and its logarithm were investigated in sets of single 2 x 2 contingency tables. The tables were generated by complete enumeration of all possible cell frequencies consistent with a single fixed margin. The bias, mean squared error (MSE), and average absolute error (AAE) were computed for all estimators using the individual table probabilities as weights. The results showed that, for the OR, Jewell's estimator usually had smaller bias, MSE, and AAE than either of the MLEs. While the differences were often slight for MSE and AAE, for bias it was sometimes substantial. For the log(OR), the UMLE usually had the lowest bias, and its MSE and AAE were only slightly greater than those for the other estimators. Overall, we recommend estimation on the log scale using the UMLE. If OR is to be estimated, Jewell's method had strong merit, although it is nonsymmetric with respect to the table orientation. In view of this, the UMLE may again be favoured in some situations.
Bias↗
The estimation of sensitivity and specificity in colorectal cancer screening methods.
The sensitivity and specificity of three screening tests for colorectal cancer were evaluated using latent class analysis. This type of analysis is useful in situations where screening tests are performed on each person and follow-up diagnostic test results are not available for individuals with negative test results. Traditional methods of evaluation, which assume these individuals to be disease free, may be biased under these circumstances. In addition to providing the parameter estimates, the latent class technique gives standard errors and permits significance tests for differences in sensitivity and specificity. It was found that the radial immunodiffusion technique was significantly more sensitive (p less than 0.001) than either the rehydrated or nonrehydrated Hemoccult II tests for detecting occult blood in patients with cancer or adenoma. While comparable to the rehydrated Hemoccult II test in terms of specificity, the radial immunodiffusion technique was significantly less specific (p less than 0.01) than the nonrehydrated Hemoccult test. Similar results were observed when restricting the analysis to cancer only.
Canada↗
A double-blind assessment of segmental sensory changes with epidural fentanyl versus epidural saline in patients undergoing extracorporeal shock-wave lithotripsy.
Segmental changes to pin prick and cold stimuli were tested in a double-blind manner in pain-free patients scheduled for extracorporeal shockwave lithotripsy (ESWL). Fifty patients were randomly allocated to receive either epidural fentanyl (100 micrograms in 10 ml normal saline) or 10 ml epidural normal saline. In a further 25 patients an epidural catheter was inserted but no solution injected. In contrast to this latter group, epidural fentanyl and normal saline both produced segmental sensory changes. There were no significant differences between fentanyl and normal saline groups in the number of patients reporting sensory changes to pin prick, rate of onset of these changes, or segmental level. For cold stimuli, more patients in the fentanyl group than in the normal saline group reported a change (16 vs. 8; P = 0.02) but the segmental level was similar. The effect of normal saline as a diluent in epidurally administered opioids may be of clinical importance.
Anesthesia, Epidural↗
Ethics in family planning.
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Beneficence↗
Effect of nitrous oxide inactivation of vitamin B12-dependent methionine synthetase on the subcellular distribution of folate coenzymes in rat liver.
The effects of nitrous oxide inactivation of the vitamin B12-dependent enzyme, methionine synthetase (EC 2.1.1.13), on the subcellular distribution of hepatic folate coenzymes was determined. In controls, cytosolic folates were 5-methyltetrahydrofolate (45%), 5- and 10-formyltetrahydrofolate (9 and 19%, respectively), and tetrahydrofolate (27%). Exposure of rats to an atmosphere containing 80% nitrous oxide for 18 h resulted in a marked shift in this distribution pattern to 5-methyltetrahydrofolate, 84%; 5- and 10-formyltetrahydrofolate, 2.1 and 9.1%, respectively; and tetrahydrofolate, 4.7%. Activity of the cytosolic enzyme, methionine synthetase, was reduced by about 84% as compared to that of air breathing controls. In controls, mitochondrial folates were 5-methyltetrahydrofolate (7.3%), 5- and 10-formyltetrahydrofolate (11.5 and 33.1%, respectively), and tetrahydrofolate (48.1%). This distribution did not change after exposure to nitrous oxide. These results show that the effects of nitrous oxide inactivation of vitamin B12 are confined to the cytosol, at least in the short term, and suggest that there is little, if any, transport of free folates between the cytosolic and mitochondrial compartments.
5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
Abortion laws and policies: challenges and opportunities.
An analysis of abortion law reform in all regions of the world in the past 20 years shows that countries have turned from a concentration upon criminality to a concern with women's health and family well-being. Pragmatic approaches to achieve liberalization of abortion laws are described. Where legal reform is unlikely, specification of professional medical standards, clarification of laws and the scope of allowable action, as well as supportive statements by government officials, can facilitate services and may ultimately have a positive influence on legal reform.
Abortion, Illegal↗
Effect of dietary methyl group deficiency on one-carbon metabolism in rats.
Amino acid-defined diets deficient in methyl groups have been shown to result in a very high incidence of hepatocellular carcinoma. It has been suggested that this is a result of decreased levels of S-adenosylmethionine and the undermethylation of DNA. Accordingly, the enzyme glycine N-methyltransferase (GNMT, EC 2.1.1.20) may play a major role in maintaining the levels of S-adenosylmethionine in liver in response to changes in dietary methionine. The effect of methyl-deficient, amino acid-defined diets on GNMT activity and S-adenosylmethionine levels in rat liver was therefore investigated. When rats were fed a defined amino acid diet containing no choline in which homocysteine was substituted for the methionine of the control diet at an equimolar level, there was a rapid and marked decrease in growth rate in spite of the fact that the rats consumed 85% of the food eaten by control rats fed a nutritionally adequate, defined amino acid diet. The GNMT activity in livers of methyl-deficient rats decreased rapidly, but there was no difference in amount of GNMT protein as measured immunologically. In methyl-deficient rats, the levels of S-adenosylmethionine were maintained but the levels of S-adenosylhomocysteine were rapidly elevated compared to control values. These changes are consistent with the postulated role of GNMT in regulating methyl group metabolism.
Amino Acids↗