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Presents several studies on clinical renal pharmacology and therapeutics. Risk factors for the urological symptoms in a cohort of users of the HIV protease inhibitor indinavir sulfate; Risk of hyperkalemia in hemodialysis patients taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers; Effects of spironolactone on potassium homeostasis in elderly patients with congestive heart failure.

A correction to the article "Face-to-face interviewing in predonation screening: lack of effect on detected human immunodeficiency virus and hepatitis C virus infections" that was published in the Vol. 46 of the 2006 issue is presented.

In prior studies in man, we have demonstrated that pressure-induced hyperemia lasts for prolonged periods as compared to the short-term hyperemia created by proximal arterial occlusion. We have analyzed this phenomenon in our well-studied rat model of skin blood flow. Skin blood flow was measured using laser Doppler techniques in Wistar Kyoto rats at the back, a nutritively perfused site, and at the plantar surface of the paw, where arteriovenous anastomotic perfusion dominates. A customized pressure feedback control device was used to vary applied pressures. At the back, pressures in excess of 80 mmHg resulted in occlusion, whereas at the paw 150 mmHg was required. The peak hyperemic flow after release of pressure was comparable to that elicited by proximal arterial occlusion with a blood pressure cuff. However, the post pressure hyperemia peak descended to a plateau value, which was 50-100% greater than baseline and continued for up to 20 min while the peak following proximal arterial occlusion returned to baseline within 4 min. At the back, post pressure hyperemia reached a maximum after application of 100 mmHg pressure. The application of higher pressures than required for occlusion produced no greater hyperemic response. At the paw, maximum post pressure hyperemia occurred at 100 mmHg, although this pressure level was not totally occlusive. Higher pressures resulted in no greater hyperemia. At the back, 10 min of occlusion produced a maximal peak value whereas 1 min was sufficient at the paw. The application of pressure to a heated probe with subsequent release, produced a hyperemic response. Normalized to baseline blood flow, there was no difference between the hyperemic responses at basal skin temperature and at 44 degrees C. There is a prolonged hyperemic response following local pressure occlusion compared to a much shorter period following proximal ischemic occlusion. One can presume two different mechanisms, one related to ischemia and the other a separate pressure related phenomenon. The thermal vasodilatory response is additive, not synergistic with the post pressure hyperemia we have demonstrated. This finding suggests that different mechanisms are involved in thermal vasodilation and post pressure hyperemia.

Aims: To develop and apply a quantitative protocol for assessing the transfer of bacteria from bleached and undyed fabrics of 100% cotton and 50% cotton + 50% polyester (poly cotton) to fingerpads or other pieces of fabric., Methods and Results: Test pieces of the fabrics were mounted on custom-made stainless steel carriers to give a surface area of 1 cm in diameter, and each piece seeded with about 10(5) cfu of Staphylococcus aureus from an overnight broth culture; the inoculum contained 5% fetal bovine serum as the soil load. Transfer from fabric to fabric was performed by direct contact using moist and dry fabrics. Transfers from fabrics to fingerpads of adult volunteers were tested using moist, dry and re-moistened pieces of the fabrics, with or without friction during the contact. Bacterial transfer from fabrics to moistened fingerpads was also studied. All the transfers were conducted under ambient conditions at an applied pressure of 0.2 kg cm(-2). After the transfer, the recipient fingerpads or fabric pieces were eluted, the eluates spread-plated, along with appropriate controls, on tryptic soy agar and the percentage transfer calculated after the incubation of the plates for 24 h at 37 degrees C., Conclusion: Bacterial transfer from moist donor fabrics using recipients with moisture was always higher than that to and from dry ones. Friction increased the level of transfer from fabrics to fingerpads by as much as fivefold. Bacterial transfer from poly cotton was consistently higher when compared with that from all-cotton material., Significance and Impact of the Study: The data generated should help in the development of better models to assess the role fabrics may play as vehicles for infectious agents. Also, the basic design of the reported methodology lends itself to work with other types of human pathogens.

The current established treatment of thrombotic thrombocytopenic purpura (TTP) is plasma exchange with fresh frozen plasma (FEP). With this treatment, there is a 49% response after seven exchanges and a 78% survival at 1 month. Although the exact cause of TTP is unknown, the presence of von Willebrand factor (VWF) multimers has been implicated in the disease. Accordingly, it has been suggested that cryosupernatant (plasma from which cryoprecipitate has been removed), which is relatively deficient in VWF multimers, might be an effective replacement fluid during plasma exchange. Patients from six centers were treated by plasma exchange with cryosupernatant. 18 patients who had failed a first course (average 7.7 exchanges) of plasma exchange with FFP. received a further seven exchanges with cryosupernatant. Subsequently, 40 previously untreated patients were exchanged with cryosupernatant. Of the 18 previously treated patients, 11 responded (defined as an increase in platelet count to > 150 x 10(9) /1 and no neurological events) after seven exchanges and 15 (83%) of the patients were alive at 1 month. The response rate in the 40 previously untreated patients was 75% at the end of seven exchanges and 95% of the patients were alive at 1 month. These values are significantly different (P < 0.05) from those reported in our earlier study and in other patients concurrently treated at the same centres with FFP when cryosupernatant was not available. Some patients who have failed to respond to plasma exchange with FFP replacement will respond to further exchange with cryosupernatant. Cryosupernatant replacement may be more effective as first-line treatment of TTP than FFP.

We used synthetic estimation and linear regression to estimate the prevalence of selected risk factors and health status indicators in small populations. The derivation was based on the sociodemographic characteristics of the populations and the relationships between these variables and the health variables, as measured by the Ontario Health Survey (OHS). The estimates were validated by a comparison with the direct results of the OHS (gold standards). Synthetic estimates were much less dispersed than the regression estimates or the direct OHS estimates. Regression estimates performed better than synthetic estimates on most validation indicators, and combined approaches performed marginally better yet, although there were few clear patterns. Although correlation coefficients with gold standards in excess of 0.8 were obtained for some variables, the estimates rarely met pre-determined criteria for accuracy. At present these techniques have limited value for public health workers, but further work is justified, especially on approaches combining synthetic and regression estimation.

In October 1988, 13 Chinese children died of acute hepatic encephalopathy in the northwestern state of Perak in peninsular Malaysia. The acuteness of the illness differed from previously reported outbreaks described in Kenya, India, and Thailand. Epidemiologic investigations determined that the children had eaten a Chinese noodle, loh see fun, hours before they died. The attack rates among those who had eaten the noodles were significantly higher than those who had not (P < 0.0001). The cases were geographically scattered in six towns in two districts along the route of distribution of the noodle supplied by one factory in Kampar town. Aflatoxins were confirmed in postmortem samples from patients. This outbreak has important public health implications for many developing countries.

A study of clinical, computerised tomography (CT) profile and outcome was made of 128 patients, diagnosed to have diffuse axonal injury based on CT criteria. The mean age was 26 years. A lucid interval was present in 37 patients and hypoxia and/or hypotension was present in 43 patients. The depth of "marker lesions" in CT correlated with Glasgow Coma Score (GCS) (p<0.02) and duration of coma (p<0.01). The presence of associated intracranial haematoma >25 ml portended an adverse outcome. A logistic regression analysis revealed age, GCS, state of perimesencephalic cisterns and pupillary dilation to be independent predictors of poor outcome. Residual sequelae (focal deficits, cognitive deficits, postconcussion syndrome) were evident in nearly half of patients with diffuse axonal injury (DAI) and a lucid interval.

Objective: To determine the incidence and timing of relapses in patients who have recovered from an acute episode of thrombotic thrombocytopenic purpura., Design: Clinical follow-up for 3 to 10 years., Setting: General community outpatient study; patients who had relapse were hospitalized., Participants: 63 of 72 surviving patients who had participated in a randomized study that compared plasma exchange and plasma infusion as treatments for thrombotic thrombocytopenic purpura and for whom continued clinical follow-up was obtained., Outcome Measures: Recurrence of thrombotic thrombocytopenic purpura as defined by a decrease in platelet count to less than 100 x 10(9)/L and by the onset of microangiopathic hemolytic anemia as identified by erythrocyte fragmentation in a peripheral blood film., Results: 37 of the 63 patients have not had recurrence of thrombotic thrombocytopenic purpura and have remained completely well; 6 patients have not had recurrence but have developed other medical problems; 3 patients have not had recurrence but have residual neurologic defects from the original episode; and 17 patients have had one or more recurrences, occurring 7 months to 8 years after the original episode. As determined by Kaplan-Meier analysis, the projected recurrence rate after 10 years in all surviving patients is 36% (95% CI, 23% to 59%)., Conclusions: More than one third of patients who survive an acute episode of thrombotic thrombocytopenic purpura will have at least one relapse during the following 10 years.

Objective: To assess the impact on clinical practice of implementing the Ottawa ankle rules., Design: Nonrandomized, controlled trial with before-after and concurrent controls., Setting: Emergency departments of a university (intervention) hospital and a community (control) hospital., Patients: All 2342 adults seen with acute ankle injuries during 5-month periods before and after the intervention., Intervention: The implementation of the Ottawa ankle rules by emergency department physicians., Main Outcome Measure: Proportions of patients referred for standard ankle and foot radiographic series., Results: There was a relative reduction in ankle radiography by 28% at the intervention hospital but an increase by 2% at the control hospital (P < .001). Foot radiography was reduced by 14% at the intervention hospital but increased by 13% at the control hospital (P < .05). Compared with nonfracture patients who had radiography during the after period at the intervention hospital, those discharged without radiography spent less time in the emergency department (80 minutes vs 116 minutes; P < .0001), had lower estimated total medical costs for physician visits and radiography ($62 vs $173; P < .001), but did not differ in the proportion satisfied with emergency physician care (95% vs 96%) or undergoing subsequent radiography (5% vs 5%). The rules were found to have sensitivities of 1.0 (95% confidence interval [CI], 0.95 to 1.0) for detecting 74 malleolar fractures and 1.0 (95% CI, 0.82 to 1.0) for detecting 19 midfoot fractures. In the following 12 months at the intervention hospital, use of radiography did not increase., Conclusions: Implementation of the Ottawa ankle rules led to a decrease in use of ankle radiography, waiting times, and costs without patient dissatisfaction or missed fractures. Future studies should address the generalizability of these decision rules in a variety of hospital settings.

A study was conducted to determine the feasibility of establishing a sentinel human immunodeficiency virus (HIV) surveillance system involving patients with sexually transmitted diseases attending private clinics and a government sexually transmitted disease clinic in Kuala Lumpur, Malaysia. Information on risk behaviours for HIV infection were also collected. A total of 84 female and 91 male patients were interviewed and tested for HIV infection; 41.7% of the women reported working as prostitutes, other occupations included masseuses, hairdressers, waitresses, salesgirls, receptionists, factory workers, and others. The most common diagnosis was gonorrhoea. Other diagnoses included non-specific genital infection, pelvic inflammatory disease, genital herpes and syphilis. 58.3% of the women had a hundred or more sex partners during the previous month; 99% had 6 or more sex partners. Only 4.8% of female patients had their male partners using condoms most of the time, 11.9% hardly used condoms at all. Of the males, 93.3% were heterosexual, while 6.7% were bisexuals, 41.1% had between 6-20 different partners in the previous year. 78.0% of them had prostitutes as their sex partners most of the time. 41.8% had experiences in Thailand and the Philippines. 73.6% never used condoms, while 19.8% only used condoms rarely. Although all patients were tested negative for HIV antibodies, lot quality assurance sampling methods indicate that the upper limits of prevalences for females and males were 3.5% and 3.3% respectively, at a 5% type I error. The study has shown that it is feasible to carry out a sentinel surveillance programme among STD patients and provided useful baseline data for future comparisons.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: To validate and refine previously derived clinical decision rules that aid the efficient use of radiography in acute ankle injuries., Design: Survey prospectively administered in two stages: validation and refinement of the original rules (first stage) and validation of the refined rules (second stage)., Setting: Emergency departments of two university hospitals., Patients: Convenience sample of adults with acute ankle injuries: 1032 of 1130 eligible patients in the first stage and 453 of 530 eligible patients in the second stage., Main Outcome Measures: Attending emergency physicians assessed each patient for standardized clinical variables and classified the need for radiography according to the original (first stage) and the refined (second stage) decision rules. The decision rules were assessed for their ability to correctly identify the criterion standard of fractures on ankle and foot radiographic series. The original decision rules were refined by univariate and recursive partitioning analyses., Main Results: In the first stage, the original decision rules were found to have sensitivities of 1.0 (95% confidence interval [CI], 0.97 to 1.0) for detecting 121 maleolar zone fractures, and 0.98 (95% CI, 0.88 to 1.0) for detecting 49 midfoot zone fractures. For interpretation of the rules in 116 patients, kappa values were 0.56 for the ankle series rule and 0.69 for the foot series rule. Recursive partitioning of 20 predictor variables yielded refined decision rules for ankle and foot radiographic series. In the second stage, the refined rules proved to have sensitivities of 1.0 (95% CI, 0.93 to 1.0) for 50 malleolar zone fractures, and 1.0 (95% CI, 0.83 to 1.0) for 19 midfoot zone fractures. The potential reduction in radiography is estimated to be 34% for the ankle series and 30% for the foot series. The probability of fracture, if the corresponding decision rule were "negative," is estimated to be 0% (95% CI, 0% to 0.8%) in the ankle series, and 0% (95% CI, 0% to 0.4%) in the foot series., Conclusion: Refinement and validation have shown the Ottawa ankle rules to be 100% sensitive for fractures, to be reliable, and to have the potential to allow physicians to safely reduce the number of radiographs ordered in patients with ankle injuries by one third. Field trials will assess the feasibility of implementing these rules into clinical practice.

Objectives: To examine the efficiency of the current use of radiography in patients with acute ankle injury. To study the judgements and attitudes of experienced clinicians in their use of ankle radiography and to thereby assess the potential for improved efficiency., Design: Two-stage study: retrospective chart review and prospective survey., Setting: Emergency departments of two adult teaching hospitals and one community hospital., Participants: The records of 1831 adults presenting with acute blunt trauma to the ankle over 5 months were examined; another 732 patients were seen by 21 full-time emergency staff physicians over a subsequent 6-month period., Measures and Main Results: Of the 1831 patients with an ankle injury in stage 1, 94.9% had had at least one radiographic series; the yield for clinically important fractures was 12.8%. In stage 2, experienced physicians predicted the probability of fracture to be 0% or 10% in 57.8% of cases. The kappa (kappa) level for interobserver agreement in 98 patients seen independently by two physicians was 0.55 (95% confidence interval [CI] 0.39 to 0.72). The area under the receiver operating characteristic curve for physicians' predicted probability was 0.88 (95% CI 0.84 to 0.92), reflecting good discrimination between fracture and nonfracture cases. Likelihood ratios for predicted probabilities ranged from 0.08 for the 0% level to 151 for the 100% level. The physicians indicated that they would feel comfortable or very comfortable in not ordering radiography in 45.9% of cases (kappa level 0.52; 95% CI 0.34 to 0.70)., Conclusions: Emergency physicians order radiography for most patients with ankle injury even though they can accurately discriminate between fracture and nonfracture cases and clearly expect most of the radiographs to give normal results. These findings suggest great potential for a more efficient use of radiography in patients with ankle injury, possibly through the use of guidelines.

Study Objective: To develop decision rules that will predict fractures in patients with ankle injuries, thereby assisting clinicians in being more selective in their use of radiography., Design: Prospective survey of emergency department patients over a five-month period., Setting: Two university hospital EDs., Participants: One hundred fifty-five adults in a pilot stage and 750 in the main study; all presented with acute blunt ankle injuries., Interventions: Thirty-two standardized clinical variables were assessed and recorded on data sheets by staff emergency physicians before radiography., Measurements: Variables were assessed for reliability by the kappa coefficient and for association with significant fracture on both ankle and foot radiographic series by univariate analysis. The data then were analyzed by logistic regression and recursive partitioning techniques to develop decision rules for predicting fractures in each radiographic series., Main Results: All 70 significant malleolar fractures found in the 689 ankle radiographic series performed were identified among people who had pain near the malleoli and were age 55 years or more, had localized bone tenderness of the posterior edge or tip of either malleolus, or were unable to bear weight both immediately after the injury and in the ED. This rule was 100% sensitive and 40.1% specific for detecting malleolar fractures and would allow a reduction of 36.0% of ankle radiographic series ordered. Similarly, all 32 significant midfoot fractures on the 230 foot radiographic series performed were found among patients with pain in the midfoot and bone tenderness at the base of the fifth metatarsal, the cuboid, or the navicular., Conclusion: Highly sensitive decision rules have been developed and will now be validated; these may permit clinicians to confidently reduce the number of radiographs ordered in patients with ankle injuries.

The authors' objective was to describe a method for measuring interobserver agreement and to determine the reliability of physical findings used by emergency physicians to assess ankle injury patients. A 3-month prospective survey was designed for use in the emergency departments of two university hospitals. Participants were a convenience sample of 100 adult blunt ankle injury patients. Pairs of emergency staff physicians assessed 22 standardized physical findings in each patient without knowledge of the other assessment. Agreement for each variable was measured by the kappa coefficient, the ratio of actual agreement to potential agreement beyond chance. The variables with the highest interobserver agreement and their kappa values were ability to bear weight (.83); bone tenderness at the base of the fifth metatarsal (.78), at the posterior edge of lateral malleolus (.75), and at the tip of the medial malleolus (.66); and combinations of bone tenderness (.76). Less reliable variables included soft tissue tenderness (.41) or degree of swelling (.18) of the anterior talofibular ligament, ecchymosis (.39), range of motion (.33), bone tenderness at the proximal fibula (-.01), and the anterior drawer sign (-.03). High kappa values indicate that several physical findings, including ability to bear weight and selected sites of bone tenderness, may be reliably assessed in ankle injury patients. This knowledge may give physicians more confidence in their physical examination and allow development of reliable clinical guidelines to diminish the reliance on radiography in ankle injuries.

Background: Thrombotic thrombocytopenic purpura is an uncommon disease with a high mortality rate even with current treatment. The cause of the syndrome and its optimal treatment are unknown. Although both plasma exchange and plasma infusion have been useful treatments, it is not clear which is superior. In this report we describe a prospective randomized trial comparing plasma exchange with plasma infusion for the treatment of thrombotic thrombocytopenic purpura., Methods: One hundred two patients with thrombotic thrombocytopenic purpura were randomly assigned to receive either plasma exchange or plasma infusion with fresh-frozen plasma on seven of the first nine days after entry into the trial. The total volume of plasma received by patients undergoing plasma exchange was three times that received by patients undergoing plasma infusion. All the patients also received aspirin and dipyridamole. The outcomes in the two groups were compared at the end of the first treatment cycle (day 9) and after six months., Results: At the end of the first treatment cycle patients receiving plasma exchange had a higher rate of response as defined by an increase in the platelet count (24 of 51 patients) than those who received plasma infusion (13 of 51, P = 0.025). Of the 51 patients treated with plasma exchange, 2 died, whereas 8 of the 51 patients who received plasma infusion died (P = 0.035). After six months the outcome in the plasma-exchange group was still superior, with a response observed in 40 of 51 patients, whereas 25 of 51 patients in the plasma-infusion group responded (P = 0.002). Eleven patients in the plasma-exchange group died, as did 19 patients in the plasma-infusion group (P = 0.036). The overall mortality was 29 percent., Conclusions: Plasma exchange is more effective than plasma infusion in the treatment of thrombotic thrombocytopenic purpura.

The prognostic value of information derived from clinical characteristics and exercise treadmill tests performed before discharge and repeated at three months was evaluated in 205 consecutive patients followed for five years. Recurrent myocardial infarction, unstable angina and mortality were tabulated. Survival was analyzed by the Kaplan-Meier life-table method and the Cox regression model. The major difference between the predischarge and three month intervals was the failure of exercise-induced ST depression to predict mortality from the predischarge test. However, it was predictive of mortality at three months when 76% survived five years with a positive ischemic response compared to 94% with a negative response (P less than 0.0005). In contrast, resting ST depression of at least 1 mm was associated with a very poor five year survival rate of 58.3% and 50% when assessed at both predischarge and three months (P less than 0.0005 and P less than 0.004, respectively). Selected univariately at the predischarge interval, the following characteristics were ranked in descending order of predictive power for five year mortality by discriminant analysis: history of previous infarction; exercise capacity; and ST depression on resting ECG greater than 1 mm. At three months, the same characteristics were selected. However, recurrent infarction and unstable angina were not predictable at either interval by any clinical or treadmill variable. Characteristics tending to reflect poor exercise capacity are stronger predictors of five year outcome than exercise-induced ischemia. While predischarge exercise testing for ST segment response failed to predict survival, this variable showed improved predictive power with repeat testing at three months.(ABSTRACT TRUNCATED AT 250 WORDS)

From 1970 to 1986, 117 patients with T1 (47) or T2 (70) epidermoid carcinomas of the floor of the mouth (SCC) were treated by iridium-192 implantation (192 Ir). The dose was prescribed according to the Paris System and varied over those years. Follow-up information was available on 116 patients. There were 46 T1N0, 47 T2N0, and 23 T2N1-3. Neck management varied for the 93 N0 patients consisting of surveillance (24 T1, 17 T2) or elective neck dissection (22 T1:all pN-, 30 T2: 20 pN-, 10 pN+). Cause specific survival rates were 94% for T1N0, 61.5% for T2N0, and 28% for T2N1-3 at 5 years. Primary local control was 93.5%, 74.5%, and 65%, respectively, and 98%, 79%, and 65% after salvage. Patients with gingival extension or a tumor size over 3 cm (T2b) had a local control of 50% (9/18) and 58% (15/26), respectively. Nodal control was 93.5% for Stage I, 85% for Stage II, and 48% for T2N1-3 patients. There was no difference in nodal control with regard to treatment policy for Stage I-II patients. There were few complications including three deaths: two from surgery and one from 192 Ir. Nodal status, tumor size defined as T1, T2a (less than or equal to 3 cm), T2b (greater than 3 cm), and gingival extension were the only independent prognostic factors. The management of T1N0 and T2N0 SCC by 192 Ir to a dose of 65 or 70 Gy, using the Paris System, is recommended for lesions 3 cm or less and without gingival extension.

Preclinical evidence has suggested that disulfiram (DS) and related compounds can decrease the toxicity and enhance the therapeutic index of cisplatin (CP). To study this further, we have performed a prospective randomized study wherein 53 patients with CP-sensitive malignancies were assigned to therapy with CP 100 mg/m2 alone (group I) or CP 100 mg/m2 and oral DS 2,000 mg/m2 (group II). Both groups were comparable with regard to sex distribution, age, performance status, prior chemotherapy, and radiotherapy. Twenty-three patients were not evaluable for response (3 refused follow-up, 18 had less than two courses, one had an early death, and one had excessive toxicity during the first cycle of treatment). Of the 30 evaluable patients (16 in group I, 14 in group II), only one in group II achieved a complete response. There was no statistically significant difference in response rate, time to progression, or median survival between the two groups. Fifty-two patients (98.1%) were evaluable for toxicity. Significant differences in toxicities were observed between the two groups: patients in group I encountered lower [Eastern Cooperative Oncology Group (ECOG) 0-1)] grades of nausea, vomiting, and ototoxicity, and patients in group II experienced higher grades (ECOG 2-3) of toxicity in general. In addition, there was no difference in nephrotoxicity between the two groups, as measured by the change in serum creatine or 24-h urine creatinine clearance over the first course of treatment. We conclude that, contrary to previously published reports, DS does not afford significant nephroprotection against CP and, in fact, enhances gastrointestinal and ototoxicities.

Risk factors in a working environment are studied mainly by case control studies or cohort studies of workers in several occupational settings. While the cohort studies are by far more powerful in detecting risk factors there are many problems associated with these studies, apart from the high cost and long duration. Some of these problems include the large number of variables involved, the evaluation of missing observations and the resulting bias, problems in selecting appropriate statistical models and analyses as well as identifying the disease subgroup (including loss to follow up). The problems are considered under four groupings: (1) identifying outcome, (ii) missing data, (iii) estimation of work exposure and (iv) statistical analysis. The apparent advantages of retrospective cohort study should be weighed against these problems when deciding on a study design. More appropriate statistical methods, other than SMR and PMR analysis, should be considered while analysing data from such studies.

A questionnaire dealing with bowel symptoms was administered to 97 outpatients referred for air-contrast barium enema. Subsequently, the barium enema was interpreted by a radiologist who did not know the results of the questionnaire. Forty-nine had normal x-rays, and 27 had uncomplicated diverticular disease. Weight loss, rectal bleeding, abdominal pain, and pain at night were as common in those with a normal examination as in those with diverticula. Symptoms of colon dysfunction included abdominal pain relieved by defecation, altered stool frequency and consistency with pain onset, abdominal distension, feeling of incomplete evacuation after defecation, and mucus in the stool. These were equally prevalent in both groups. Therefore, no symptoms could be ascribed to the presence of diverticula.

Sickled erythrocytes showed reduced glutathione peroxidase and catalase activities in comparison to normal erythrocytes. In addition, increased levels of superoxide dismutase and 'peroxidation potential' as well as fluorescent lipid pigments and malonaldehyde suggestive of membrane lipid peroxidation were found in sickled erythrocytes. Finally, sickled erythrocytes showed membrane 'bound' Heinz bodies as well as reduced membrane lipids and unsaturated fatty acids. From these observations, it is suggested that membrane lipid peroxidation occurs in sickled cells.

Various methods have been proposed and tried to limit the extent of myocardial damage at the time of infarction. We chose to assess the usefulness of intravenous magnesium in this regard because of its important role in myocardial metabolism and function and the suggestion of its deficiency in ischemic hearts. A double-blind randomized trial was carried out and results analyzed in 76 patients. At the end of the infusion period the mean serum Mg++ level for the treated group was 3.6 versus 1.9 mg/dl for the control group. The estimated size of infarction (as measured by MB-CK release) was not significantly smaller overall in the treated group (37.4 +/- 4.3 vs. 45.6 +/- 4.6 MB-CK g/Eq), but was significantly smaller in the treated subgroup without heart failure (31.6 +/- 5.8 vs. 44.7 +/- 4.8 MB-CK g/Eq). A trend toward less ventricular ectopy was seen in the group treated with magnesium. There was significantly less lidocaine used for the treatment of ventricular dysrhythmias in this group. Magnesium supplementation in patients undergoing acute coronary events is promising and deserves further study.

The administration of aflatoxin B1 to rats on days 17 and 19 of pregnancy caused increased synthesis of the total lipids and the fatty acids, and decreased synthesis of the phosphatidyl choline in 21-day-old fetal lung. Aflatoxin B1 caused toxicity in the fetal lung as evidenced by the excessive accumulation of the lamellar bodies and the osmiophilic spheroids in the type II cells and the alveolar lumen, respectively. The rearrangement of the lamellar form to the continuous sheet-like tubular myelin form was reduced in the alveolar lumen of the treated lung.

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.

To assess the potential of fomites and environmental surfaces as vehicles in the transmission of rotaviral diarrhoea, disks (1 cm diameter) of various porous and non-porous materials were contaminated with about 10(5) plaque-forming units of the Wa strain of human rotavirus (HRV) suspended in faecal matter. The contaminated disks were then held for 10 days at either room temperature (22 +/- 2 degrees C) or 4 degrees C with the relative humidity (RH) at the high (85 +/- 5%), medium (50 +/- 5%) or low (25 +/- 5%) level. Survival was longer on non-porous surfaces at the lower temperature and at lower humidity. In contrast, survival on porous surfaces was very variable; better on cotton-polyester than on poster card or paper currency on which HRV survived very poorly. These results suggest that under the right environmental conditions, HRV-contaminated objects could play a role in the transmission of rotavirus infections in hospitals, nursing homes and day-care centres.

Frequent serum sampling of CK-MB and total CK levels was carried out in 100 patients during and up to 48 hours following aortocoronary bypass surgery. Using an ion exchange chromatography method for CK-MB determination, significantly higher serum CK-MB levels (peak 46.1 +/- 5.2 cf. 31.3 +/- 2.2 u/L), but not total CK levels were present 6 to 16 hours postoperatively in those with new Q waves in the ECG. Serum levels of CK-MB in those patients with uncomplicated surgery were defined. New post-operative Q waves were seen in only one half of cases with frankly abnormal CK-MB curves and seriously underestimated the incidence of perioperative infarction. Peak levels of CK-MB in patients with new Q waves occurred within 16 hours of surgery suggesting that infarction is usually an intraoperative or early post-operative event.

Seventy-nine patients with moderate to severe left ventricular dysfunction who underwent aortocoronary bypass grafting between 1971 and 1977 had follow-up heart catheterization at a mean interval of 3 years. Thirty-three patients (42%) had angiographic improvement in left ventricular function at follow-up and 18 (25%) had a decrease in left ventricular end-diastolic pressure. Fifty-eight patients (73%) had improvement in angina of at least one New York Heart Association class at follow-up. There was no correlation between late improvement in left ventricular function and improvement in angina. Improvement in left ventricular function did not correlate with preoperative indices of severity of coronary disease or with indices of completeness of surgical repair.

To assess the benefit of immediate surgical reperfusion over conventional medical treatment during the first acute evolving transmural myocardial infarction, 68 patients presenting within 4 hours of onset of chest pain were randomized into a medical group and a surgical group. Both groups were comparable for age, sex, coronary risk factors, location of infarct, and coronary anatomy. Radionuclide global ejection fraction at 48 hours after admission was 45 +/- 15% for the medical group versus 50 +/- 15% for the surgical group; at 3 months, ejection fraction values were 51 +/- 13% and 51 +/- 13%, respectively (p = NS). The average radionuclide wall-motion scores (normal, 3) at 3 months were 2 +/- 0.6 for the medical group and 2 +/- 0.7 for the surgical group. There were three (8.8%) early and four (11.7%) late deaths in the medical group and only one (2.9%) early death in the surgical group. Urgent surgical reperfusion in acute evolving myocardial infarction is a safe and effective procedure that appears to reduce early and late mortality but does not appear to improve left ventricular function.

Although adrenalectomy is usually associated with an impairment of ammonium and/or titratable acid excretion by the kidney, it is uncertain whether rates of renal net acid excretion are also reduced. Further, it is unclear whether the absence of the adrenal gland itself or other factors of adrenal insufficiency mediate such changes in renal acidification parameters. For example, dramatic increases in ammonium excretion can accompany correction of the hyperkalemia seen in adrenal insufficiency. There is also evidence that reduced rates of acid excretion can result from changes in food intake, urine flow rate, urine pH or distal sodium delivery rates. With these considerations in mind, we undertook studies to isolate the chronic effects of adrenalectomy on renal net acid excretion rates in the unanaesthetized rat. To avoid supranormal potassium stores, we gave the adrenalectomized animals potassium-restricted diets. In balance studies, urine flow rates, urine pH, food intake, and distal sodium delivery rates were all successfully controlled for 13 days by pair feeding and by appropriately changing the sodium and potassium contents of diets. Adrenalectomized rats excreted less net acid than did control animals with or without ammonium chloride loading. Further, the severe metabolic acidosis associated with ammonium chloride loading was clearly mitigated by steroid replacement. Accordingly, we conclude that the adrenal gland is essential for normal renal net acid excretion.