Time use, time management and academic achievement among occupational therapy students

The purpose of this study was to examine time use patterns and variables related to time use, including feelings about time use, time management, and academic achievement, among normal college students. Time use was examined from the perspective of the model of human occupation. One hundred and six male and female occupational therapy students enrolled at Worcester State College in Worcester, MA completed two self-report questionnaires and a demographic questionnaire. The subjects completed the Occupational Questionnaire (Riopel Smith, Kielhofner, and Watts, 1986) which measured time use (activities engaged in during a typical 24-h period), and feelings about time use (related to competence, value, enjoyment) for the activities they reported. In addition, they completed the Time Management Questionnaire (Britton and Tesser, 1990, which measured their time attitudes, preferences for short range planning, and preferences for long range planning. The results of the study suggest that older students and those experiencing role overload perceive themselves as less competent, and value and enjoy their time use less than younger students and those with fewer role demands. In addition, the use of time management was related to academic achievement. Implications of the findings are discussed.

Minimal change glomerulonephritis in a 90-year-old patient: what is the ideal approach?

We report the case of a 90-year-old lady who presented with full-blown nephrotic syndrome. Percutaneous renal biopsy allowed us to confirm the diagnosis of minimal change glomerulopathy; she entered a 2-year period of remission after a 6-month course of prednisone (starting dose 1.5 mg/kg). The patient sustained minor effects of both renal biopsy and corticotherapy. Percutaneous renal biopsy is justified in the very elderly because the risk of mortality and morbidity related to corticotherapy outweigh the risk related to percutaneous renal biopsy, providing high-risk patients are excluded, such as amyloidosis or abnormal coagulation or uncontrolled arterial hypertension.

Epidural blood patch in a seven-year-old child

We present an unusual case of postoperative headache in a child after an epidural block. A seven-year-old girl (ASA 1) was scheduled to undergo a urological procedure under general anaesthesia combined with an epidural technique for intra- and postoperative analgesia. Although there was no evidence of dural puncture when the block was performed, the patient developed a headache postoperatively. The headache, which was accompanied by neck pain, appeared in the sitting or standing position and was relieved by decubitus. According to the mother, her child had never complained of those symptoms in the past. After independent evaluation by an anaesthetist and a neurologist, a postdural puncture headache (PDPH) was considered the most likely diagnosis. As oral analgesics failed to provide relief, and epidural blood patch (EBP) using 10 ml autologous blood was performed under light sedation. This was followed by resolution of the symptoms. Epidural injections of opioids and local anaesthetics are becoming increasingly popular for pain management in children. This implies that there may be an increasing number of unintentional dural punctures that may result in more PDPHs in children. Epidural blood patches are effective in treating PDPHs in adults but their use has been reported very rarely in children. Resolution of the patient's symptoms following EBP supported the diagnosis while illustrating that EBP can be useful in the treatment of PDPH in children.

Improvement of hepatorenal syndrome by transjugular intrahepatic portosystemic shunt

Hepatorenal syndrome (HRS) is a functional renal failure occurring in advanced liver cirrhosis with ascites. It is due to renal cortical vasoconstriction resulting from complex hemodynamic disturbances related to cirrhosis and portal hypertension. There is no consistently effective therapy except for liver transplantation. We report a case of severe HRS in a patient with advanced liver cirrhosis and portal hypertension. Three sessions of hemodialysis were performed because of severe renal failure (serum urea 83 mg/dl, serum creatinine 6 mg/dl). Creation of an intrahepatic portosystemic shunt reduced the portocaval gradient from 18 to 7 mm Hg. Spectacular improvement of the renal function was observed soon after the procedure, with spontaneous recovery of diuresis and a return of serum urea and creatinine to baseline values. The patient unfortunately died 2 months later from adult respiratory distress syndrome post emergency surgery for a massive bleed related to a duodenal ulcer. Throughout this episode, the renal function remained stable. The postmortem examination showed histologically normal kidneys. We conclude that the intrahepatic portosystemic shunt can improve renal function in cirrhotic patients with HRS; it could be used in patients awaiting liver transplantation to reverse preoperative renal failure.

Maximizing the benefits of thrombolytic therapy for acute myocardial infarction

Thrombolytic therapy is a huge advance in the management of acute myocardial infarction (AMI). The results of large clinical trials over the past 9 years have unequivocally demonstrated its benefit: of every 1000 patients treated 30 will be saved, at a cost of two cases of nonfatal cerebral hemorrhage and seven of noncerebral major hemorrhage. The concurrent use of acetylsalicylic acid increases the benefit of thrombolytic therapy. Sales figures for thrombolytic agents indicate that their use in Canada is less than optimal and lags behind that in several European countries. Major educational efforts are needed to promote awareness of the efficacy of thrombolytic therapy and of optimal approaches for maximizing its potential benefit for patients with AMI.

[Advances in the treatment of gastroesophageal reflux. Intraoperative calibration of posterior fundoplication]

Posterior partial fundoplication can be as effective as total fundoplication in the long-term control of gastroesophageal reflux if the gastric fundus valve is encircled around the distal esophagus for no less than 270 degrees to obtain effective pressures in the newly built sphincter. In order to minimize the adverse effects, to reach constant results and to guarantee the reproducibility of the technique we have modified the 270 degrees posterior fundoplicatio (formerly described by Lind) according to the following principles: 1) the length of the gastric valve must be limited to 3 cm for each side of the esophagus; 2) the gastric valve must be fixed to the right and left side of the hiatal orifice by a single stitch; 3) the gastric valve must be calibrated with an intraoperative manometry, this allowing the standardization of the valve pressure to an average value of 35 mmHg by varying its wrapping angle; 4) the hiatal orifice must not be closed unless it is large enough for thoracic migration of the gastroplasty. Since 1984 to 1991 43 patients with proven gastroesophageal reflux not controlled by medical treatment were submitted to surgery. Twelve Nissen procedures (NP) and 31 posterior calibrated fundoplications (PCF) were performed; PCF seemed to be superior to NP in terms of postoperative mobility. After two years 20 patients treated with PCF were evaluated clinically, manometrically and by 24-hour pH monitoring. No dysphagia was reported; in two patients a pH-metric, asymptomatic relapse was observed, while one patient complained mild and occasional heartburn.(ABSTRACT TRUNCATED AT 250 WORDS)

[Demography perspectives and forecasts of the demand for electricity]

"Demographic perspectives form an integral part in the development of electric load forecasts. These forecasts in turn are used to justify the addition and repair of generating facilities that will supply power in the coming decades. The goal of this article is to present how demographic perspectives are incorporated into the electric load forecasting in Quebec. The first part presents the methods, hypotheses and results of population and household projections used by Hydro-Quebec in updating its latest development plan. The second section demonstrates applications of such demographic projections for forecasting the electric load, with a focus on the residential sector." (SUMMARY IN ENG AND SPA)

Effects of a modified dance-based exercise on cardiorespiratory fitness, psychological state and health status of persons with rheumatoid arthritis

Cardiorespiratory function and exercise tolerance appear very limited in persons with rheumatoid arthritis (RA). Many studies have demonstrated that aerobic exercise training is beneficial to prevent physical deconditioning without inducing adverse effects on an individual's joints and general health. The present study was conducted to demonstrate that a dance-based exercise program is a safe and efficient activity to improve physical fitness and psychological state in persons with RA. A group of 19 persons (mean age, 49.3 +/- 13 yr) participated in a 12-wk exercise program (twice weekly), whereas 10 persons (mean age, 49.4 +/- 12 yr) served as controls. Health status, use of medication, joint pain and swelling, physical fitness, activity of daily living and psychological state were assessed at baseline, after the 12-wk training program and 6 mo after the end of the program. Exercise training induced a mean improvement of 13% in aerobic power, with the highest values reaching 40%. No significant changes were observed in joint status, even though the count of painful joints tended to decrease in the exercise group. Positive changes in depression, anxiety, fatigue and tension were observed after the 12-wk exercise program. These findings provide some evidences in favor of aerobic exercise in individuals with RA. Furthermore, it is of primary interest to note that a weight-bearing activity with limited ground impacts do not provoke short-term adverse effects on joint status. Further studies, however, are required to determine the long-term effect of weight-bearing exercise on the health status of individuals with RA.

Spawning patterns and interspecific matings of sympatric white (Catostomus commersoni) and longnose (C. catostomus) suckers from the Gouin reservoir system, Quebec

White (Catostomus commersoni) and longnose (C. catostomus) suckers from the Gouin reservoir, Quebec, and a small upstream lake (Lac des Cinq Miles) spawned in the same stream. White suckers numerically dominated the runs in all years; however, abundances of both species decreased eightfold during a year when the reservoir level was lowered for maintenance. Return rates of individuals of both species tagged during the spawning run were poor in the following year, and only a few fish (<0.6%) skipped a year to spawn 2 years later. Although some individuals of both species occurred at all monitored spawning areas, white suckers concentrated their spawning activity over sites with boulders, whereas longnose suckers were most abundant over gravel. Differences in the courtship behaviour of the two species initially discouraged interspecific matings. However, white sucker males ultimately participated in 32% of the female longnose sucker matings, though spawning of male longnose suckers with female white suckers was not observed. White suckers spawned in groups or in pairs, whereas in all instances longnose suckers spawned with two or more males.

Induction of metaphase arrest in cleaving Xenopus embryos by MAP kinase

The natural arrest of vertebrate unfertilized eggs in second meiotic metaphase results from the activity of cytostatic factor (CSF). The product of the c-mos(xe) proto-oncogene is thought to be a component of CSF and can induce metaphase arrest when injected into blastomeres of two-cell embryos. The c-Mos(xe) protein can directly activate the mitogen-activated protein kinase kinase (MAP kinase kinase) in vitro, leading to activation of MAP kinase. MAP kinase and c-Mos(xe) are active in unfertilized eggs and are rapidly inactivated after fertilization. Microinjection of thiophosphorylated MAP kinase into one blastomere of a two-cell embryo induced metaphase arrest similar to that induced by c-Mos(xe). However, only arrest with c-Mos(xe) was associated with activation of endogenous MAP kinase. These results indicate that active MAP kinase is a component of CSF in Xenopus and suggest that the CSF activity of c-Mos(xe) is mediated by MAP kinase.

A translation-based generation effect in bilingual recall and recognition

Two experiments were performed with incidental study procedures in which generation effects were observed for relatively balanced French-English bilingual subjects on measures of both free recall and recognition. Experiment 1 used a within-subject design, and Experiment 2 used a between-subject design. In both experiments, reading translations and reading same-language repetitions generally resulted in similar amounts of retention. Experiment 2 and Experiment 3 also showed that the generation effect was abolished under intentional study procedures because of an enhancement of reading-based retention. The results suggested that previous failures to obtain a translation-based generation effect may have been due to the use of intentional study procedures. The pattern of effects was explained in terms of a single-code model of bilingual linguistic representation and an individual-item processing interpretation of the generation effect.

Measurement errors in standard visual analysis of coronary angiograms: consequences on clinical trials

OBJECTIVE

The usual assessment of coronary angiograms by standard visual analysis was compared with the assessment by quantitative computer analysis to provide evidence of the consequences of measurement errors attributable to visual assessment in the evaluation of coronary stenoses in clinical trials.

METHODS

Angiograms obtained in 151 patients enrolled in a double-blind randomized controlled trial assessing the effect of fish oil supplementation on restenosis were evaluated by both visual and quantitative methods. Proportions of patients with unsuccessful angioplasty and proportions of patients with restenosis according to visual and quantitative methods were compared by standard statistical methods.

RESULTS

Of the 151 patients who were considered successfully dilated by visual interpretation, 32 were not considered successfully dilated by quantitative analysis. With quantitative computer analysis, evaluation of restenosis on the 119 successfully dilated patients documented a protective effect of fish oil against restenosis (30.5% of treated patients versus 48.3% of control patients, P < 0.05). Visual evaluation of restenosis six months after angioplasty misclassified 10% of patients in each treatment group and failed to demonstrate a protective effect of fish oil against restenosis.

CONCLUSIONS

Misclassification by visual assessment of both success and restenosis in the present trial led to underestimating the true effect of fish oil in the prevention of restenosis. Accurate and objective methods, such as quantitative computer analysis, are thus required for evaluating the effects of interventions on coronary arteries.

Double-blind, randomized, controlled trial of fish oil supplements in prevention of recurrence of stenosis after coronary angioplasty

BACKGROUND

Previous studies suggest that recurrence of coronary stenosis after percutaneous transluminal coronary angioplasty (PTCA) might be prevented with dietary supplements rich in omega-3 fatty acids. The purpose of the present study was to evaluate this hypothesis. In addition, the relation between usual dietary consumption of omega-3 fatty acids and restenosis was assessed.

METHODS AND RESULTS

A double-blind, randomized, controlled trial was conducted in which 205 patients undergoing a first PTCA received 15 capsules per day containing 1 g of either fish oil (2.7 g/day of eicosapentaenoic acid, 1.8 g/day of docosahexaenoic acid) or olive oil. The treatment was started 3 weeks before PTCA and continued for 6 months thereafter. Dietary intake was assessed by food frequency questionnaire. At 6 months after PTCA, patients underwent a control angiography. All angiographic lesions were measured by quantitative computer analysis. Four criteria were used to define restenosis. Restenosis occurred less often in the fish oil group (22.0-35.6% depending on the definition) than in the control group (40.0-53.3%). After controlling for other risk factors of restenosis, the association of fish oil supplementation with a lower frequency of restenosis was statistically significant (p = 0.03) for three of four definitions. After adjustment, a dietary intake of omega-3 fatty acids of more than 0.15 g/day was also associated with a lower frequency of restenosis (p less than or equal to 0.03).

CONCLUSIONS

This trial documented the protective effect of fish oil supplements on the recurrence of coronary stenosis 6 months after PTCA. The study results suggest that a dietary intervention could be useful in preventing restenosis.

Pharmacokinetics of tissue-type plasminogen activator during acute myocardial infarction in men. Effect of a prostacyclin analogue

BACKGROUND

Coronary reocclusion complicates the thrombolytic therapy of acute myocardial infarction despite the routine use of aspirin. This is consistent with experimental studies demonstrating that multiple agonists, in addition to thromboxane A2, mediate the platelet activation underlying reocclusion. Consequently, a more potent antiplatelet therapy with a broader spectrum of activity than aspirin may be required in this setting. Prostacyclin and its more stable analogue, iloprost, inhibit platelet aggregation to all known agonists and exert an additional effect over aspirin alone. Experiments in animal models have demonstrated, however, that iloprost increases the clearance of tissue-type plasminogen activator (t-PA) and impairs thrombolysis in vivo. This study examines whether a similar interaction occurs in humans.

METHODS AND RESULTS

Twelve patients with acute myocardial infarction received t-PA intravenously, 60 mg in the first hour and a maintenance infusion of 13.3 mg/hr for 3 hours. Patients were assigned in a double-blind fashion to iloprost (2 ng/kg/min) or placebo following the initial 90 minutes of the maintenance infusion of t-PA. Iloprost decreased mean arterial blood pressure (-10 +/- 2.9 mm Hg, p less than 0.05) but did not alter heart rate. Steady-state plasma iloprost concentration was 591 +/- 64 pmol/l. At this concentration, iloprost markedly inhibited platelet aggregation in vitro, particularly in the presence of aspirin. Steady-state clearance of t-PA was unchanged by iloprost (454 +/- 65 versus 443 +/- 136 ml/min in controls, p = NS). Furthermore, neither elimination kinetics nor plasma protein binding of t-PA was altered by iloprost.

CONCLUSIONS

At plasma levels that exert a potent antiplatelet effect, iloprost did not alter the pharmacokinetics of t-PA in men. Prostacyclin analogues may prove useful as an adjunct to plasminogen activators, particularly in patients at high risk for thrombotic reocclusion.

Effects of a fish oil supplement on blood pressure and serum lipids in patients treated for coronary artery disease

OBJECTIVE

The purpose of this study was to evaluate the effects of a concentrate of fish oil on blood pressure and serum lipids in patients treated for coronary artery disease.

DESIGN

One hundred and twenty-five patients were randomly assigned to receive 15 g/day MaxEPA (4.5 g eicosapentaenoic and docosahexaenoic acids) or olive oil. Blood pressure and serum lipids were measured at enrollment and six months thereafter.

MAIN RESULTS

As an important proportion of antihypertensive or antianginal drug users stopped their usual medication during the trial, blood pressure increased in both groups. The increase in systolic blood pressure was less in the fish oil group than in the control group (P = 0.002). Serum triglyceride levels decreased markedly in the fish oil group while they remained constant in the control group (P = 0.0001). Fish oil supplementation had no effect on total cholesterol and only marginal independent influence on high density lipoprotein and low density lipoprotein cholesterol levels.

CONCLUSIONS

In conclusion, fish oil supplementation has a beneficial effect on blood pressure and serum triglycerides in patients treated for coronary artery disease.

[A retrospective study on the use of preoperative percutaneous drainage in uncomplicated obstructive jaundice]

This study concerns a retrospective analysis of the use of preoperative percutaneous biliary drainage in the treatment of obstructive jaundice complicated or not by cholangitis. From 1980 to 1987, 87 patients were selected; among these, only those with bilirubin greater than 5 mg% and an overt indication to surgery were included in the study. It was so possible to match two relatively homogeneous populations, e.g. patients submitted to preoperative drainage vs patients not drained. According to our experience, a preoperative percutaneous biliary drainage does not affect postoperative mortality, incidence of immediate postoperative complications and length of hospitalisation. These results are probably linked to a predominant use of the drainage in absence of infectious complications.

Effect of maturational changes in myosin content and morphometry on airway smooth muscle contraction

We studied the relationship of airway morphometry, the content of myosin heavy-chain and isoform stoichiometry, and the distribution of bronchoconstrictor responses in the airways of maturing swine. Lungs were excised in 2-wk-old farm swine (2ws; n = 13) and 10-wk-old swine (10ws; n = 13), and tracheal smooth muscle strips and bronchial rings from generations 2-5 were fixed for in vitro isometric measurement of force generation. Split samples were placed in formaldehyde solution or glutaraldehyde for light- or electron-microscopic morphometry or frozen for analysis of tissue myosin content. The rank order of force generation elicited by both receptor- and nonreceptor-dependent mechanisms for both 2ws and 10ws was generation 4 greater than 3 greater than or equal to 2. For all matched airway generations, contractile force was 25-100% greater in 2ws than 10ws. Differences in force generation were not related to morphometric differences in smooth muscle mass content among airways. The relative cross-sectional area of smooth muscle derived by computerized morphometry was 5.5-7% for each airway generation and did not change with age. Electron-microscopic morphometry demonstrated comparable myocyte content within muscle bundles for all airways in both age groups. In generation 4 airways, myocyte size in 2ws (27.3 +/- 0.8 nuclei/2,500 microns2) hypertrophied approximately 15% in 10ws (20.4 +/- 0.6 nuclei/2,500 microns2; P less than 0.01). Tissue content of myosin measured by computerized laser densitometry of gel electrophoresis of homogenates was greater in trachea from 2ws than 10ws (135 +/- 10 vs. 90 +/- 4 micrograms/g tissue; P less than 0.01); homology of 200- and 205-kDa isoforms was confirmed by Western blot against polyclonal myosin antibody and Cleveland digest analysis of each band. Differences in contractile forces between generations in 2ws and 10ws were not correlated to functional myosin isoform content. We demonstrate a maturational downregulation of contractile forces in maturing swine. This response is independent of smooth muscle receptor distribution and is not related to morphological changes in airways muscle mass, cellularity, changes in content of nonmyocyte tissues, or tissue content of functional myosin isoform.

GTP-dependent membrane fusion during hepatocarcinogenesis and liver regeneration

Rough microsomes were isolated from homogenates of livers of rats bearing hepatomas as well as from homogenates of livers of rats 24 and 48 h after partial hepatectomy. When incubated in the presence of GTP in a cell-free system to assay membrane fusion these membranes were observed to have a greater capacity (1.4 to 5 fold) for GTP-dependent fusion than homologous membranes from control non-proliferating liver tissue. The enhanced GTP-dependent membrane fusion may reflect changes in membrane properties related to cell proliferation.

Effect of maturation on topographic distribution of bronchoconstrictor responses in large diameter airways of young swine

We studied the effect of maturation on the topographic distribution of airway constriction in Generations 0 (trachea) through 6 in fourteen 2-wk-old swine (2ws) and sixteen 10-wk-old swine (10ws) in vivo and in excised airways from seven 2ws and seven 10ws in vitro. Animals were anesthetized with chloralose-urethane and received beta-adrenergic blockade and vagotomy prior to generation of random-order, dose-response curves with i.v. methacholine (MCh) and histamine (His) or serotonin (5HT) given intravenously. Lung resistance (RL) was measured, and airway diameter was assessed by tantalum bronchograms obtained at functional residual capacity for each dose of agonist. Baseline RL was substantially greater in 2ws (48 to 62 cm H2O/L/s) than in 10ws (9 to 11 cm H2O/L/s; p less than 0.001 for all groups). Intravenous infusion of 10(-6) mol/kg MCh caused a 416 +/- 110% increase in RL in 2 ws and a 314 +/- 32% increase in RL in 10 ws (p = NS); airway diameter (Daw) decreased by 10 +/- 1% (Generation 2) to 27 +/- 4% (Generation 6) in 2ws and from 8 +/- 2 (Generation 2) to 17 +/- 4% in 10ws. Intravenous infusion of 10(-6) mol/kg His caused a 513 +/- 85% increase in RL in 2ws and a 276 +/- 17% increase in RL in 10 ws (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Development and prospective application of quantitative 2-day stress-rest Tc-99m methoxy isobutyl isonitrile SPECT for the diagnosis of coronary artery disease

The clinical diagnostic accuracy of 2-day stress/rest quantitative Technetium-99m (Tc-99m) methoxy-isobutyl-isonitrile (Tc-sestamibi) single photon emission computerized tomography (SPECT) was assessed in a validation population of 61 patients from two different sites using two different camera/computer systems. The study population was made up of 53 catheterized patients, 29 from Cedars-Sinai Medical Center (CSMC) and 24 from the University of Texas Southwestern Medical Center (UTSMC), and eight UTSMC patients with a less than 5% pre-test likelihood of coronary artery disease. Interpretation employed gender-specific normal limits developed in an additional 15 men and 8 women at CSMC with less than a 5% likelihood of significant coronary artery disease. The results from CSMC compared with those from UTSMC were not different from each other. The overall sensitivity for detection of patients with coronary artery disease (greater than or equal to 50% stenosis) was 94% (CSMC: 92%, UTSMC: 95%). Overall specificity in the five patients with normal coronary arteriograms was 80% (CSMC: 67%, UTSMC: 100%). The normalcy rate in patients with a low likelihood of coronary artery disease was 88%. Vessel sensitivity was 85% (CSMC: 84%, UTSMC: 85%), while vessel specificity was 71% (CSMC: 72%, UTSMC: 69%). There was also no significant difference in the sensitivities and specificities between male and female populations. In addition, the agreement with coronary angiography for assessment of disease extent (normal coronary arteriogram, single or multivessel disease) was 75% (kappa = 0.6 +/- 0.1). This study demonstrated that Tc-sestamibi SPECT by quantitative analysis is accurate for the detection and localization of coronary artery disease. Furthermore, the CSMC quantitative method was shown to provide similar diagnostic accuracy when applied to data acquired at a different site using a different camera/computer system.

Interpreting subtle inconsistency: a developmental-clinical perspective

The meaning attributed to subtle inconsistent messages by outpatient clinical and nonclinical adolescents was studied. The verbal and nonverbal cues used to attribute this meaning were also studied. Both groups attributed meaning to consistent messages accurately and without hesitation and attributed meaning to subtle inconsistent messages with much less consensus and clarity. The clinical group used a verbal focus at times and a nonverbal one at other times to interpret consistent and inconsistent messages that were indicative of a developmentally transitional phase. Nonclinical adolescents always used a nonverbal focus to interpret consistent and inconsistent messages in a developmentally age-appropriate manner.

Growth factor binding and bioactivity in human kidney epithelial cell cultures

Insulinlike growth factors (IGF) and epidermal growth factor (EGF) are produced in renal tissue, as are specific receptors for these hormones. To evaluate the significance of these observations to regulation of renal tubular cell proliferation, we have examined the interaction of IGF and EGF with cultured human proximal tubular epithelial cells (HPT). HPT cells showed specific binding of IGF-1, insulin, and EGF. IGF-1 binding was inhibited by antibody to the type 1 IGF receptor (alpha-IR3). Insulin receptors and type 1 IGF receptors were identified by bifunctional cross-linking. IGF-1, insulin, and EGF stimulated [3H]thymidine incorporation by 77, 73, and 87%, respectively. Half maximal stimulation by IGF-1, insulin, and EGF were produced with 4 X 10(-9) M, 2.5 X 10(-8) M, and 8 X 10(-10) M concentrations of these hormones. Alpha-IR3 inhibited stimulation of thymidine incorporation by IGF-1 and insulin but had no effect in EGF-stimulated thymidine incorporation. EGF and high concentrations of insulin both stimulated cell proliferation by 83 and 79%, respectively. These data are consistent with regulation of tubular epithelial proliferation by IGF-1, insulin, and EGF and suggest that the mitogenic activity of both insulin and IGF-1 is mediated by the type 1 IGF receptor.

Morphogenesis of endoplasmic reticulum in Xenopus oocytes after microinjection of rat liver smooth microsomes

We have determined the kinetics of endoplasmic reticulum (ER) reconstitution following insertion of rat-liver smooth microsomes (SM) into Xenopus oocyte cytoplasm using electron microscopy as well as cytochemistry and thick-section 3-dimensional reconstruction. Oocytes were fixed 0, 10, 20, 40, 80, and 120 min after microinjection with SM and processed for thin- and thick-section electron microscopy. At 0 min postinjection, rat liver SM were observed as small vesicles and were loosely dispersed amongst oocyte organelles. At 10 min, tubules were discerned among many elongate vesicles; and these structures comprised large cytoplasmic regions delimited by mitochondria and yolk platelets. By 20 min, segregation of transplanted organelles yielded yolk-platelet-free regions composed of few vesicles but increasingly numerous, long and anastomosing tubules. By 40 min, a network with numerous tubular branches and fenestrations was observed among the few remaining vesicles. By 80 min, transformation of rat liver SM into a complex network of branching and anastomosing tubules was complete. Three-dimensional reconstruction revealed the network to be composed of interconnecting elements consisting of anastomosing tubules. The reconstituted network of anastomosing tubules in Xenopus oocytes was compared to the network of anastomosing tubules in rat liver hepatocytes and was found to be essentially identical. Network formation occurred in oocytes pretreated with either vinblastine (40 microM) or nocodazole (0.166 microM), and network organization was maintained in oocytes treated with the same drugs after microinjection and reconstitution. We conclude that SM retain sufficient molecular information for rapid self-assembly into structures resembling those in the cells from which they were derived. Both the assembly and maintenance of ER structure in oocyte cytoplasm are microtubule-independent. The formation of such structures following microinjection of SM into living cells provides a unique assay for this type of membrane subfraction.

A multicenter randomized trial of ionic (ioxaglate) and nonionic (iopamidol) low-osmolality contrast agents in cardiac angiography

A multicentered double-blind randomized study was performed comparing the electrocardiographic and hemodynamic changes induced by two new low osmolar contrast agents used for cardiac angiography. The low osmolar ionic (ioxaglate) contrast agent was compared with a low osmolar nonionic (iopamidol) contrast agent in 150 patients with angina pectoris undergoing angiography. Systolic blood pressure, left ventricular end-diastolic pressure, heart rate, and QT interval were measured just before and for 90 s following the left ventricular angiography and selective coronary angiography. Each group was also evaluated for adverse events and quality of radiographic images. Following left ventricular angiography, the systolic blood pressure dropped slightly in both groups with a greater decrease seen in the iopamidol group at 5 s (p less than 0.05). After selective right and left coronary angiography, systolic blood pressure decreased transiently and equally in both treatment groups. The left ventricular end-diastolic pressure increased after the ventriculogram in both groups (15.9 +/- 6.3 to 18.9 +/- 8.6 mmHg in the ioxaglate group and 16.1 +/- 6.7 to 20.1 +/- 7.8 mmHg in the iopamidol group), the change being significant only in the iopamidol group (p less than 0.05). Heart rate increased slightly but significantly in the ioxaglate-treated patients following left ventricular angiography (71.4 +/- 15.2 to 74.4 +/- 13.7 beats/min) (p less than 0.01). QT interval transiently increased following left ventriculography with ioxaglate (407 +/- 59.5 to 420 +/- 58.3 ms) (p less than 0.05) compared with iopamidol.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet and vascular function during coronary thrombolysis with tissue-type plasminogen activator

Platelet activation may limit the response to tissue-type plasminogen activator (t-PA) during coronary thrombolysis in humans. As an index of platelet activation, we assessed thromboxane A2 biosynthesis during coronary thrombolysis with intravenous t-PA in patients with acute myocardial infarction. Urinary 2,3-dinor-thromboxane B2, a metabolite of thromboxane A2, was increased to a peak of 3,327 +/- 511 pg/mg creatinine (n = 12) following administration of intravenous t-PA and remained elevated for 48 hours. This increase was abolished by pretreatment with aspirin 325 mg orally (n = 6), indicating de novo biosynthesis of thromboxane A2 rather than washout of preformed metabolites during reperfusion. Prostacyclin (PGI2) biosynthesis, determined by excretion of 2,3-dinor-6-keto-PGF1 alpha, also increased after t-PA administration. However, this increase was less pronounced in patients who reperfused (28 +/- 3.3 ng.hr/mg creatinine) than in patients who failed to reperfuse (118 +/- 30 ng.hr/mg creatinine, p less than 0.05). These data provide evidence of platelet activation during coronary thrombolysis with t-PA. In patients who reperfuse, the reduction in PGI2 biosynthesis may be a marker of reperfusion injury to the vasculature and may further amplify platelet activation.

Detection of GTP-binding proteins in purified derivatives of rough endoplasmic reticulum

As a first step in determining the molecular mechanism of membrane fusion stimulated by GTP in rough endoplasmic reticulum (RER), we have looked for GTP-binding proteins. Rough microsomes from rat liver were treated for the release of ribosomes, and the membrane proteins were separated by SDS/polyacrylamide-gel electrophoresis. The polypeptides were then blotted on to nitrocellulose sheets and incubated with [alpha-32P]GTP [Bhullar & Haslam (1987) Biochem. J. 245, 617-620]. A doublet of polypeptides (23 and 24 kDa) was detected in the presence of 2 microM-MgCl2. Binding of [alpha-32P]GTP was blocked by 1-5 mM-EDTA, 10-10,000 nM-GTP or 10 microM-GDP. Either guanosine 5'-[gamma-thio]triphosphate or guanosine 5'-[beta gamma-imido]triphosphate at 100 nM completely inhibited binding, but ATP, CTP or UTP at 10 mciroM did not. Pretreatment of microsomes by mild trypsin treatment (0.5-10 micrograms of trypsin/ml, concentrations known not to affect microsomal permeability) led to inhibition of [alpha-32P]GTP binding, suggesting a cytosolic membrane orientation for the GTP-binding proteins. Two-dimensional gel-electrophoretic analysis revealed the 23 and 24 kDa [alpha-32P]GTP-binding proteins to have similar acid isoelectric points. [alpha-32P]GTP binding occurred to similar proteins of rough microsomes from rat liver, rat prostate and dog pancreas, as well as to a 23 kDa protein of rough microsomes from frog liver, but occurred to distinctly different proteins in a rat liver plasma-membrane-enriched fraction. Thus [alpha-32P]GTP binding has been demonstrated to two low-molecular-mass (approx. 21 kDa) proteins in the rough endoplasmic reticulum of several varied cell types.

Infectious mononucleosis complicated by necrotizing epiglottitis, dysphagia, and pneumonia

Although infectious mononucleosis is usually a benign illness, life-threatening complications may occur. We describe a 17-year-old pregnant girl who developed necrotizing epiglottitis and dysphagia progressing to aspiration pneumonia and respiratory failure. The factors predisposing to this life-threatening complication are discussed.

Electrophoretic protein blots as aids in choosing fixatives for immunocytochemistry

We used electrophoretic protein blots prepared from polyacrylamide gels to test the effect of different fixatives on the antigenicity of rough endoplasmic reticulum (RER) peptides from rat liver. Protein blots were prepared by the procedure of Towbin et al. (Proc Natl Acad Sci USA 76:4350, 1979), treated with different fixatives, rinsed to inactivate non-specific reactive sites, and then reacted with rabbit polyclonal anti-rat liver RER antibodies, followed by peroxidase-conjugated anti-rabbit antibodies. On the basis of differences in immunostaining densities as determined by densitometry, we found that RER peptides displayed differential sensitivities to various fixatives. Anti-rat liver RER antibodies and the immunogold technique were applied to methacrylate sections of in vitro fixed rat liver rough microsomes. Specific labeling was observed over the microsomes and was shown by quantitation to vary in a similar manner to the immunostaining of specific peptides in protein blots following different fixations. We conclude that protein blots may serve as useful tools for screening the effects of different fixatives on cell antigenicity, and therefore may be helpful in immunocytochemical studies.

Marked platelet activation in vivo after intravenous streptokinase in patients with acute myocardial infarction

We assessed thromboxane biosynthesis as an index of platelet activation in 6 patients with acute myocardial infarction receiving intravenous streptokinase. Urinary 2,3-dinor-thromboxane B2 and plasma 11-dehydro-thromboxane B2, major enzymatic metabolites of thromboxane A2, were markedly increased after intravenous streptokinase (11,063 +/- 2758 pg/mg creatinine and 33 +/- 10 pg/ml, respectively) compared with levels in patients not receiving thrombolytic therapy (502 +/- 89 pg/mg creatinine and 3 +/- 0.7 pg/ml). Prostacyclin biosynthesis also increased markedly after streptokinase coincident with the increase in thromboxane A2 formation. Administration of aspirin between the time of onset of coronary thrombosis and reperfusion both in man and in a canine preparation demonstrated that this reflected thromboxane biosynthesis de novo and not metabolism of preformed inactive thromboxane B2 washed out from the coronary circulation. Since the platelet is the major source of thromboxane A2, these findings suggest that there is marked platelet activation after coronary thrombolysis with streptokinase. Studies in vitro demonstrated that streptokinase enhanced platelet activation in a dose-dependent manner, resulting in the secondary release of thromboxane A2. The increase in platelet activation and thromboxane A2 biosynthesis may limit the therapeutic effect of intravenous streptokinase in acute myocardial infarction.

Platelet activation in unstable coronary disease

Pathological and clinical studies have suggested that platelets have a role in the pathogenesis of unstable angina and myocardial infarction. However, the relation of platelet activation to episodic ischemia in patients with unstable angina is unknown. We assessed the biosynthesis of thromboxane and prostacyclin as indexes of platelet activation in patients with stable and unstable coronary disease by physicochemical analysis of metabolites in plasma and urine. Prostacyclin biosynthesis was markedly elevated in patients with acute myocardial infarction and correlated with plasma creatine kinase (r = 0.795; P less than 0.001). The largest rise in thromboxane synthesis was observed in patients with unstable angina, in whom 84 percent of the episodes of chest pain were associated with phasic increases in the excretion of thromboxane and prostacyclin metabolites. However, 50 percent of such increases were not associated with chest pain, possibly reflecting silent myocardial ischemia. These data indicate that platelet activation occurs during spontaneous ischemia in patients with unstable angina. The increment in prostacyclin biosynthesis during such episodes may be a compensatory response of vascular endothelium that limits the degree or effects of platelet activation. If so, biochemically selective inhibition of the synthesis or action of thromboxane A2 would be desirable in the treatment of unstable angina. In contrast, thromboxane inhibitors or antagonists would not be expected to be effective in patients with chronic stable angina, in whom there was no increase in the formation of thromboxane A2.

Biosynthesis of thromboxane in patients with systemic sclerosis and Raynaud's phenomenon

Thromboxane A2, the predominant cyclo-oxygenase product of arachidonic acid in platelets, is a potent vasoconstrictor and platelet agonist. Analysis of urinary metabolites by gas chromatography and mass spectrometry is a specific non-invasive method of measuring the biosynthesis of thromboxane that avoids the problem of platelet activation ex vivo. Excretion of the major urinary thromboxane metabolite, 2,3-dinor-thromboxane B2, was significantly increased (p less than 0.001) in 10 patients (nine women) with systemic sclerosis complicated by Raynaud's phenomenon compared with healthy controls (486 (SD 88) v 162 (38) ng/g creatinine) and increased further in the patients (to 1007 (212) ng/g creatinine) during application of a cold stimulus sufficient to induce digital vasoconstriction. Consistent with an increase in platelet-vascular interactions in vivo, excretion of a prostacyclin metabolite was also significantly increased (p less than 0.005) in the patients with systemic sclerosis (248 (39) v 112 (10) ng/g creatinine) and tended to increase further on cooling. Biosynthesis of thromboxane is increased in patients with systemic sclerosis and may exacerbate digital vasospasm that such patients develop when cold. This observation and the concomitant increase in the formation of prostacyclin provide a rationale for evaluating compounds that prevent the synthesis of thromboxane A2 or inhibit its action while preserving the potential homoeostatic role of prostacyclin.

Adiaspiromycosis in striped skunks in Alberta, Canada

Pulmonary adiaspiromycosis was diagnosed in seven of 25 striped skunks (Mephitis mephitis) in east-central Alberta. The infection varied from mild, where only microscopic lesions were seen, to severe, where gross lesions of grayish-white nodules were observed in the lung parenchyma. Mild lesions were restricted to the lung, while severe lesions extended to the tracheobronchial and mediastinal lymph nodes. Histologically, the lesions were characterized by a centrally located fungal spherule, surrounded by granulomatous inflammation. The morphology of the fungal spherules was consistent with that of Emmonsia crescens. By electron microscopy, the fungal cells had an outer thick fibrillar wall and an inner cytoplasm filled with large lipid vacuoles with relatively few mitochondria, ribosomes or glycogen inclusions. The absence of endosporulation and budding suggested that each fungal cell in the lung represented a separate inhaled spore. Infection was by inhalation, nevertheless adiaspores may disseminate to the regional lymph nodes.

Effects of indomethacin on systemic and coronary hemodynamics in patients with coronary artery disease

The effects and possible mechanisms of actions of indomethacin on systemic and coronary hemodynamics were studied in 17 patients with coronary artery disease. Group I patients (12) were given either indomethacin or placebo in the absence of prior cyclooxygenase inhibition and group II (five) were given indomethacin after prior treatment with 2600 mg of aspirin. In group I, systolic blood pressure rose from a baseline of 136 +/- 5 mm Hg to a peak level of 158 +/- 8 mm Hg 5 minutes after drug (p less than 0.01). This was associated with a fall in coronary blood flow and a rise in coronary vascular resistance from a baseline of 1.36 +/- 0.4 mm Hg/ml/min to 1.99 +/- 0.7 mm Hg/ml/min 5 minutes after indomethacin (p less than 0.01). Immunoreactive thromboxane B2 levels fell from 191 to 1.4 ng/ml. No changes were noted in plasma renin activity, angiotensin II, or catecholamine levels. Immunoreactive thromboxane B2 levels were undetectable throughout the study period in group II patients and the blood pressure response to indomethacin was attenuated. Baseline coronary blood flow was significantly higher (p less than 0.01) and baseline coronary vascular resistance significantly lower (p less than 0.01) than in group I. At all time points after indomethacin, the fall in coronary blood flow was greater and the increase in coronary vascular resistance less in group II versus group I (p less than 0.001). These findings suggest a dissociation between the effect of indomethacin on systemic and coronary hemodynamics, the former apparently being more prostaglandin-dependent than the latter.

Lack of efficacy of nafazatrom, a novel anti-thrombotic compound, in patients with coronary artery disease

Nafazatrom (Bay G 6575) is a novel antithrombotic compound, which acts by stimulation of prostacyclin as well as by inhibition of lipoxygenase enzymes. To determine its effects on exercise performance in coronary artery disease patients, a double-blind study was conducted. Twenty patients with coronary artery disease underwent an exercise stress test before and 2 hours after administration of placebo or nafazatrom (1.2 gm). Before the drug administration, there was evidence of enhanced platelet activity, as reflected by elevated resting plasma beta thromboglobulin and thromboxane B2 concentrations. Plasma 6-keto-PGF1 alpha levels were undetectable in most patients. All coagulation tests were in the normal range. None of these parameters changed with exercise. Administration of placebo or nafazatrom before the exercise stress test did not significantly influence any of the coagulation or platelet function parameters or plasma concentrations of thromboxane B2 and 6-keto-PGF1 alpha. This lack of effect was evident both at rest and upon exercise. Compared to placebo, nafazatrom did not significantly increase exercise tolerance time or exercise-induced symptoms. In conclusion, nafazatrom did not influence exercise performance in patients with coronary disease.

Endogenous biosynthesis of prostacyclin during cardiac catheterization and angiography in man

The potent platelet inhibitory and vasodilator properties of prostacyclin suggest that levels of this substance may be of relevance to drug action and pathologic processes in the coronary vascular bed. Attempts to estimate the coronary secretion rate of prostacyclin have relied on measurements of metabolites obtained via cardiac catheter, usually as an adjunct to coronary angiography. To test the hypothesis that such procedures might themselves perturb endogenous biosynthesis of prostacyclin we used mass spectrometry to measure plasma levels of 6-keto-prostaglandin (PG) F1 alpha across the coronary vascular bed, as well as to assess the excretion of a major urinary metabolite, 2,3-dinor-6-keto-PGF1 alpha (PGI-M), in patients undergoing cardiac catheterization. PGI-M excretion increased variably from a median 100 to 205 pg/mg creatinine (p less than .01) during catheterization with angiography and remained elevated 2 to 4 hr after initiation of the procedure. However, cardiac catheterization without angiography also stimulated metabolite excretion, perhaps reflecting catheter-induced vascular trauma. The direct effect of radiocontrast media on vascular release of prostacyclin was indicated by increased PGI-M excretion in healthy volunteers administered intravenous radiocontrast and by studies of the canine coronary artery and jugular vein in vitro. Measurement of plasma 6-keto-PGF1 alpha after left heart catheterization showed that levels in aortic (21 +/- 8 pg/ml) and coronary sinus (14 +/- 2 pg/ml) blood were increased compared with peripheral venous levels (less than or equal to 4 + 1 pg/ml) determined before this procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Non unionized professional pilots in Québec : from myth to real.]

In this article, the working conditions of 875 non syndicated professional pilots who work on small third class airline companies are analysed. This research was made on behalf of the pilots themselves through the intermediary of the Association of the Air People of Quebec. First, a socio-demographic profile of this masculine man power is outlined, made of young and low income persons. Emphasis is put on the working characteristics that are risk factors for health and security and on sources of stress for the pilots which are: the seasonal peaks, recurrent unemployment, remuneration by the volume of work done, un-sufficient rest, the employer's threats, the deficient state of the airplanes. It is also shown that certain symptoms are present in these workers: a general fatigue, headaches and insomnia. Lastly, their perception of their work and the satisfaction gained from it is presented.

The effects of organic nitrates on prostacyclin biosynthesis and platelet function in humans

The results of prior studies indicate that nitroglycerin stimulates prostacyclin release by cultured endothelium and by the coronary vasculature in vivo. However, the accuracy of these findings in coronary vasculature relies on plasma samples obtained from the circulation via cardiac catheters, a procedure we have shown to stimulate prostacyclin release, thereby confounding interpretation of drug action. We studied the effects of short-acting (nitroglycerin) and long-acting (isosorbide dinitrate) nitrates on a noninvasive index of prostacyclin synthesis, excretion of urinary 2,3-dinor-6-keto-PGF1 alpha. Nitroglycerin was infused into six subjects to either a maximum of 480 micrograms/min or until mean arterial pressure fell by 20 mm Hg. Urine was collected for negative ion chemical ionization gas chromatographic, mass spectrometric analysis before and during the nitroglycerin infusion and for two 2 hr periods after nitroglycerin. The peak nitroglycerin infusion rate was 387 +/- 67 micrograms/min, which caused a fall in supine blood pressure (systolic/diastolic) of 11 +/- 5/14 +/- 4 mm Hg and a 12 +/- 3 beats/min increase in heart rate. Excretion of 2,3-dinor-6-keto-PGF1 alpha (pg/mg creatinine) was unchanged from control infusion values (106 +/- 19.5) either during (123 +/- 21) or after (134 +/- 14.6; 139 +/- 36) nitroglycerin infusion. Platelet aggregation to arachidonic acid (0.33 to 1.33 microM) and epinephrine (1 to 10 microM) ex vivo was inhibited in only one subject in whom excretion of 2,3-dinor-6-keto-PGF1 alpha was unaltered. Serum thromboxane B2 was not changed by nitroglycerin infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical and ultrastructural integrity of the saphenous vein conduit during coronary artery bypass grafting. Preliminary results of the effect of papaverine

Factors associated with early and late graft patency related to aorta-coronary artery bypass grafting with a reversed segment of saphenous vein are clinically important. The present investigation examines the biochemical and electron microscopic integrity of this venous conduit intraoperatively with regard to pharmacologic manipulation with papaverine. Portions of saphenous vein were analyzed in 22 patients undergoing coronary artery bypass operations. Levels of a stable derivative of prostacyclin, 6-keto-PGF1 alpha, were measured by radioimmunoassay. Scanning as well as transmission electron microscopy was also performed. In particular, the efficacy of local vein treatment with papaverine, a phosphodiesterase inhibitor, was evaluated. We found that levels of 6-keto-PGF1 alpha in venous effluent showed a biphasic response with initial elevation followed by a relative depression after papaverine exposure. There were no such changes observed in veins subjected to a balanced electrolyte solution (Plasma-Lyte). In addition, levels of the platelet-inhibitory substance 6-keto-PGF1 alpha in venous tissue were less in papaverine-treated veins than those found in veins treated only with the balanced electrolyte solution (Plasma-Lyte). Furthermore, evidence for ultrastructural damage was also somewhat greater in the papaverine-treated group. An alternative method of dilating the saphenous vein after harvesting, which involves the creation of the proximal aorta-coronary anastomosis first and gentle finger manipulation subsequently, appeared to minimize venous injury. Under present clinical conditions, it appears that some amount of injury is inevitable during harvesting and suturing of the human saphenous vein during coronary bypass grafting.