Showing papers by "Maastricht University published in 1987"

Comparing the effects of problem-based and conventional curricula in an international sample

Abstract: In this article, the authors review 15 studies that compare various educational outcomes of problem-based, community-oriented medical curricula with those of conventional programs. The data suggest that problem-based curricula provide a student-centered learning environment and encourage an inquisitive style of learning in their students as opposed to the rote memorization and short-term learning strategies induced by conventional medical education. In addition, community-oriented schools appear to influence the career preferences of their students. The few data available show that significantly larger proportions of graduates from these schools seek careers in primary care. Some of the studies reviewed suggest that students in conventional programs perform somewhat better on traditional measures of academic achievement than do students in problem-based curricula. However, these differences, if any, tend to be very small. Data with respect to performance on instruments measuring clinical competence are inconclusive. Finally, the authors discuss the difficulties involved in carrying out comparative research at the curriculum level.

Effect of tissue fixation on anti-bromodeoxyuridine immunohistochemistry.

Abstract: We investigated the influence of various fixatives on monoclonal anti-BrdUrd antibody binding of BrdUrd-substituted DNA in tissue sections of routinely processed mouse small intestine after in vivo administration of BrdUrd. For denaturing fixatives such as ethanol or Carnoy's fluid, a standard denaturation protocol showed specific crypt cell labeling. With cross-linking agents such as formalin and glutaraldehyde, a remarkable increase in staining intensity was obtained after tissue digestion with pepsin before acid denaturation. The optimal pepsin concentration was determined for maximal immunoreactivity combined with acceptable morphology.

Carbohydrate feeding and glycogen synthesis during exercise in man.

Abstract: In 7 male cyclists glycogen synthesis during exercise and rest was studied. Each subject did two exercise trials (A and B), in random order. In both trials, after determining the maximal workload (Wmax), intermittent exercise was given to exhaustion. After the exhaustive exercise and taking a muscle biopsy the subjects either exercised at 40% Wmax for 3 h (trial A) or rested for 3 h (trial B), during which they consumed approximately 2 l of a 25% malto-dextrine drink in both trials. After 3 h rest (trial A) or 3 h of mild exercise (trial B) a second muscle biopsy was taken for total glycogen and histochemistry (ATPase and PAS). Blood glucose and insulin levels were elevated during the first 2 h of exercise (p less than 0.05). Glycogen depletion was most pronounced in type I and to a less extent in type IIA fibers. In trial A muscle glycogen increased from 136 +/- 66 to 199 +/- 71 mmol/kg DW, and in trial B from 145 +/- 56 to 257 +/- 79 mmol/kg DW. During exercise glycogen repletion was restricted to type IIA and IIB fibers, whereas during rest glycogen synthesis occurred both in type I and type II fibers. The present study demonstrates that oral carbohydrate administered during exercise may not only provide substrate for energy metabolism, but can also be utilized for glycogen synthesis in the non-active muscle fibers.

Retrospective analysis of the prognostic significance of DNA content and proliferative activity in large bowel carcinoma.

Abstract: In the present study we have evaluated the prognostic significance of ploidy levels and proliferative activity in 279 cases of large bowel carcinomas which were included in a surgical prospective randomized trial. Ploidy levels and proliferative activity were determined on nuclei isolated from paraffin-embedded tissues of 279 colorectal carcinoma patients, with a mean follow-up of 51.9 months. Product limit survival analysis demonstrated a borderline significant association ( P = 0.0689 by generalized Breslow; P = 0.0336 by generalized Savage) between ploidy and survival, with a 75th quantile survival of 49.8 months for patients with diploid tumors and 35.9 months for patients with aneuploid tumors. After stratification for staging, Dukes' C cases showed a statistically significant association between tumor ploidy and survival ( P = 0.0224 by generalized Breslow, P = 0.0110 by generalized Savage). Product limit survival analysis for proliferative activity and survival showed a similar outcome with the strongest association in Dukes's C stage of disease (75th quantile survival of 38.9 months for low proliferative and 18.0 months for high proliferative tumors).

Reversibility of tachycardia-induced left ventricular dysfunction after closed-chest catheter ablation of the atrioventricular junction for intractable atrial fibrillation.

Abstract: Significant left ventricular (LV) dysfunction resulting from chronic uncontrolled tachycardia represents a diagnostic dilemma. In patients with a depressed LV function and tachycardia, the tachycardia may have developed as a consequence of a cardiomyopathy or may be the cause of the LV dysfunction [1-3]. In this report we demonstrate that intractable atrial fibrillation (AF) may be associated with LV dysfunction, and that closed-chest catheter ablation, by modifying conduction in the atrioventricular node, may be of therapeutic value.

The daily life of ambulatory chronic mental patients.

Abstract: The purpose of this research is to describe in greater detail than is typically done the daily life experiences of 11 ambulatory chronic mental patients and 11 nonpsychiatric controls. The subjects, although diagnostically heterogeneous, were representative of Dutch chronic mental patients. The Experience-Sampling Method was used to signal subjects randomly 10 times a day for 6 consecutive days to fill out self-rating forms assessing mental state and contextual information at the moment of the signal. Compliance was good. In time-allocation comparisons with nonpsychiatric subjects the patients were found to live relatively "normal" lives. As expected, their psychopathology was influenced by social environments such as being alone, at home, or in society at large. Contrary to other studies that stress the social isolation of such individuals, the chronic subjects reported feeling better away from home and among people than normal subjects. When alone, chronic patients reported daydreaming more and noted a tendency to drift away from thoughts about current activities. Mental state fluctuations and daily interactions, characteristic of this group, are examined in relation to theories of vulnerability and coping style of chronic mental patients, with an eye to individualized treatment applications.

The effect of preoperative internal and external biliary drainage on mortality of jaundiced rats.

Abstract: • Mortality following abdominal infection induced by cecal ligation and puncture was studied in rats with obstructive jaundice and after relief of the obstruction by preoperative internal or external biliary drainage. Four groups of adult Sprague-Dawley rats were used: (1) common bile duct ligation (BDL), (2) BDL followed by internal drainage after two weeks, (3) BDL followed by external drainage after two weeks, and (4) sham operation. The serum bilirubin concentration was significantly increased in the BDL group and returned to normal following internal and external drainage. Mortality in the sham group was 16.5% and increased to 83.3% following BDL, but it decreased significantly (25%) to near-normal values after preoperative internal drainage. However, after external drainage no significant reduction in mortality (63%) was found. These findings confirm the poor results of preoperative external drainage in previous studies and establish the efficacy of internal biliary drainage in a well-controlled experimental model that has to be evaluated in the clinical situation. ( Arch Surg 1987;122:731-734)

Does exercise give an additional effect in weight reduction regimens

Abstract: The effects of dieting and exercise on RMR, body composition and maximal aerobic power were studied in 12 obese women. The subjects were paired on the basis of their body mass index and divided into a diet (D) and a diet + exercise group (DE). The treatment consisted of a 5-week period with a low-energy formula diet of 2.9 MJ and an 8-week period with a mixed diet of 1.7 MJ supplemented with 1.8 MJ normal foodstuffs. DE trained 4 h per week at 50-60 per cent of their maximal aerobic power with aerobics and fitness exercises. Body composition was determined by hydrostatic weighing and RMR was measured from 03.00 to 06.00 hours in a respiration chamber. Maximal aerobic power was measured on a continuously braked ergometer. The measurements were done at week 0, after 4 weeks (week 5), and after 12 weeks (week 13). Weight loss after 4 weeks was 8.2 kg (DE) and 7.9 kg (D) and after 12 weeks 13.2 kg (DE) and 12.2 kg (D). There were no significant differences between the groups. Fat loss was also not statistically different between DE (6.7 and 10.9 kg) and D (6.0 and 9.4 kg). Both groups showed a significant decrease in RMR per kilogram FFM after 12 weeks (DE: 18.2 per cent and D: 26.5 per cent). There was also a significant decrease in RMR for D (19.9 per cent) after 4 weeks but not for DE (12.2 per cent).(ABSTRACT TRUNCATED AT 250 WORDS)

Investigating mental disorders in their natural settings.

Abstract: This issue of The Journal of Nervous and Mental Disease reports fundamental research into the nature of mental disorders, using both new and traditional time-sampling approaches. The studies present convincing findings gathered in a variety of patient populations and demonstrate the utility of using quantitative and replicable methods in psychiatric research and clinical care. Research that adequately describes the person in context as well as the influence of situations on mental state has proved difficult. Methods such as the diary and Experience-Sampling Method that explore experiences in daily life overcome some of the shortcomings of previous psychiatric research strategies, such as reliance on retrospective recall and the failure to take the variability of mental state more fully into account. The studies in this issue introduce techniques for creating a data base for psychiatric research and clinical practice that is anchored in patient experience and behavior.

Branches of the thoracic sympathetic trunk in the human fetus

Abstract: The segmental organization of the thoracic sympathetic trunk and all its ramifications was studied in 6 human fetuses (16-22 weeks) by means of the acetylcholinesterase in toto staining method. Each trunk was divided into 12 sympathetic segments. A segment is defined as that part of the sympathetic trunk which is connected via its rami communicantes with one spinal nerve, without discriminating between grey and white rami. The diameter of the rami communicantes and their direction towards the spinal nerves are variable. The number of peripheral segmental ramifications of the trunk is much larger than assumed previously. Each thoracic sympathetic segment gives off at least 4-5 nerves. Three categories of nerves are discerned: (1) large splanchnic rootlets confined to the greater, lesser and least thoracic splanchnic nerves, (2) medium-sized splanchnic nerves directed towards thoracic viscera, some of which give off branches towards costovertebral joint plexuses and, described for the first time in man, (3) small nerves which ramify extensively and form nerve plexuses in the capsule of the costovertebral joints. The majority of the ramifications is formed by the nerves of the third category. The existence of Kuntz's nerve, connecting the 2nd intercostal nerve and 1st thoracic spinal nerve, is confirmed in four specimens. The nerve plexuses of the costovertebral joints receive a segmentally organized innervation: they receive their input from the neighbouring sympathetic segment and the one cranial to it. It is concluded that the thoracic sympathetic branches in man show a complex, segmentally organized pattern and may have a considerable component of somatosensory nerve fibers. The complex relationships must be taken into account in surgical sympathectomies.

Human specific anti-type IV collagen monoclonal antibodies, characterization and immunohistochemical application.

Abstract: This paper describes two new monoclonal antibodies reactive with human specific type IV collagen epitopes in frozen as well as routinely fixed and processed tissue sections. The antibodies (1042 and 1043) were raised against human placental type IV collagen and were shown by immunoblotting and ELISA tests to react exclusively with type IV collagen determinants. Extensive immunohistochemical survey studies on panels of tissues from various species, using unfixed cryosat sections, demonstrated that antibody 1042 reacted only with human type IV collagen whereas antibody 1043 in addition reacted with rabbit type IV collagen. All tissues showed homogeneous staining of the basement membrane, indicating that the detected epitopes did not show organ-specific distribution.

Value of programmed electrical stimulation using a standardized ventricular stimulation protocol in hypertrophic cardiomyopathy.

Abstract: To establish the value of programmed electrical stimulation in patients with hypertrophic cardiomyopathy (HC), patients with HC with or without documented ventricular arrhythmias were studied by a standardized stimulation protocol.

A comparison of high-frequency oscillation superimposed onto backup mechanical ventilation and conventional mechanical ventilation on the distribution of exogenous surfactant in premature lambs.

Abstract: . Twenty-six premature iambs were treated by traeheal instillation [14C]labeled natural sheep surfactant before the onset of breathing or after the establishment of respiratory distress syndrome 30 min after birth. Half of both groups were subsequently ventilated for 3 h with 100% O2 by conventional mechanical ventilation (CMV) and half by high frequency oscillation superimposed onto backup mechanical ventilation (HFOV). Mean airway pressure, arterial blood pressures, and heart rate were recorded continuously. Arterial blood gases and pH were obtained every 15 min. After sacrifice, the distribution of radiolabeled surfactant was quantified and alveolar expansion was evaluated by morphometrics. At comparable oxygenation, mean airway pressures were significantly lower in the lambs treated with surfactant at birth (groups CMVB and HFOV-B) than in lambs on CMV and treated with surfactant during RDS (group CMV-R). Mean airway pressures in both groups of lambs on HFOV (groups HFOV-B and HFOV-R) were comparable at values lower than in group CMV-R and higher than in group CMV-B. The distribution of radiolabeled surfactant was more homogeneous in lambs treated at birth and not different for both types of ventilatory assistance. Morphometrics demonstrated significantly better expansion of the alveoli of lambs ventilated with HFOV than of those on CMV, irrespective of the timing of surfactant administration. These results indicate that prophylactic surfactant administration at birth leads to a better distribution of surfactant than rescue treatment with surfactant after the establishment of respiratory distress syndrome and is not affected by a subsequent type of ventilatory assistance. Rescue treatment with surfactant and subsequent HFOV leads to better oxygenation and alveolar expansion at comparable mean airway pressures than rescue treatment followed by CMV.

Rapid staining of Campylobacter pyloridis.

Abstract: Sir: Marshall & Warren’s report (1984) on active chronic gastritis has renewed the interest in micro-organisms in the stomach, now called Campylobacter pyloridis. Culturing of gastric biopsies is the most specific method for the identification of campylobacter in gastric mucosa. Since the micro-organism requires a very specific medium and only grows under microaerophilic conditions this method is of limited sensitivity (30-60%) (Marshall & Warren 1984, Jones, Lessels & Eldridge 1984). Therefore, most investigators rely on histological staining of Campyfobacfer pyloridis for the diagnosis of campylobacter-associated gastritis. For this purpose the silver staining technique of Warthin & Starry (1920) is commonly applied. This method however has certain drawbacks. It requires technical skill and is time consuming as well as expensive. Moreover. silver precipitation in the mucus covering the gastric mucosa may interfere with the interpretation of the findings. False positive and false negative results are thus possible. Rathbone, Wyatt & Heatly (1926) mentioned a modified Giemsa as an alternative staining method for the demonstration of campylobacter-like micro-organisms. The modification consists of omission of the differentiation step with acetic acid (Gray, Wyatt & Rathbone 1986). We have compared the Warthin Starry staining technique with this modified Giemsa stain. Gastric biopsies from 34 patients with cultureproven campylobacter-associated gastritis, were stained and examined blindly. With the Warthin Starry technique 27 cases of campylobacterassociated gastritis were positively identified, whereas 32 cases were detected using the modified Giemsa stain. The modified Giemsa stain, therefore, appears to be superior in predicting a positive culture compared with the Warthin Starry staining method. In our experience this is mainly due to silver precipitation preventing the detection of small numbers of Campylobacter pyloridis. We conclude that the modified Giemsa stain, apart from being cheaper and easier to perform, is more sensitive and therefore appears to be preferable for the histological demonstration of Campylobacter pyloridis in gastric biopsies. H.V .P.J.Potters R.J.L.F.Loffeld EStobberingh J.P.van Spreeuwel J. W. Arends* Departments of *Pathology, Interns[ Medicine arid Microbiology, University of Limburg, Mnastricht, The Netherlands

Specificity of interoceptive fear to panic disorders

Abstract: It has been argued that fear of interoceptive sensations is a maintaining factor in panic disorders. This study investigated whether interoceptive fears are specific to panic disorders or whether they are a feature of neurosis in general. Twenty-nine panic patients, 28 nonpanicking neurotic controls, and 29 normal controls were compared for their scores on a 14-item questionnaire intended to measure interoceptive fears. Indeed it was found that panic patients scored considerably higher than both control groups, whereas no significant differences emerged between the two control groups. It is concluded that interoceptive fear is diagnostically specific to panic disorders.

Vasopressin and human behaviour

Abstract: Peptides related to the pituitary hormone vasopressin (VP) have been found to influence aspects of memory processes and learning in laboratory animals (De Wied, 1969; see De Wied, 1983, for review). This finding has led to the suggestion that VP might have a clinical application in the treatment of human memory disorders. Unfortunately, it is not simple to state whether VP has been found effective. This is because clinical studies differ with respect to the nature of the patient population (e.g., brain trauma, alcoholism, depression) and the methods of testing used. In addition, there is wide variation in pharmacological parameters, such as the dose, route, and frequency of peptide administration. Accordingly, some studies report positive effects of VP administration, whereas others are negative (Jolles, 1983b).

The social ecology of anxiety. Theoretical and quantitative perspectives.

Abstract: Experience sampling is a relatively new research approach that captures relevant variations in experience and symptoms in the course of everyday life. In this paper, a socioecological frame of reference that integrates psychological, historical, cultural, and developmental theories about anxiety phenomena will be illustrated using quantitative descriptions of anxiety and avoidance behaviors gathered with the Experience-Sampling Method. The interaction between anxiety symptoms and the environment in which they occurred is explored in a case study that points to possibilities for future research and the establishment of therapeutic approaches that are optimally suited to the individual patient.

Long-term antihypertensive therapy with beta-blockers: submaximal exercise capacity and metabolic effects during exercise.

Abstract: The effects of long-term (6 months) antihypertensive treatment with three different types of beta-blockers (propranolol, nonselective without ISA; pindolol, nonselective with ISA; metoprolol, beta 1-selective without ISA) on submaximal exercise capacity and metabolic variables during submaximal endurance exercise were studied in seven subjects with essential hypertension. Exercise tests were performed on a bicycle ergometer at 70% of estimated VO2 max. Similar reductions of resting and exercise blood pressure and exercise heart rate were obtained with the three beta-blockers. Exercise time was significantly reduced by all three beta-blockers during chronic antihypertensive therapy. The reduction tended to be more pronounced after 5-6 months of treatment than after 1 week (P = 0.06). During exercise, the plasma glycerol and nonesterified fatty acid concentrations were reduced. Plasma glucose concentration was reduced at the end of the exercise test during propranolol treatment only. Plasma lactate concentrations tended to be increased, but the difference was significant during pindolol treatment only. Oxygen uptake tended to decrease and respiratory exchange ratio to increase. Plasma potassium concentrations during exercise were significantly increased with all three beta-blockers. The effects on the metabolic variables during exercise were similar after 1 week and during long-term (20/24 weeks) beta-blocker treatment. The study shows that submaximal endurance exercise capacity is impaired in patients with essential hypertension on beta-blocker therapy and that the impairment is maintained during long-term antihypertensive beta-blocker treatment.

Hepatic uptake and storage of warfarin. The relation with the target enzyme vitamin K 2,3-epoxide reductase.

Abstract: The mechanisms of the reported dose-dependent warfarin pharmacokinetics were investigated using [14C]warfarin. When administered in microdoses (9 micrograms i.v.) to rats (male Wistars, 270-300 g), a steep distribution phase (T1/2 = 0.25 hr) was followed by a relatively slow beta-phase (T1/2 = 40 hr). The observed volume of distribution was 390 ml. This pharmacokinetic behavior contrasted highly with the one seen for higher (greater than 0.2 mg/kg) doses (unlabeled) warfarin; volume of distribution = 45 ml, T1/2 = 12.5 hr. If a "macrodose" (0.2 mg/kg) preceded (16 hr) the "microdose," "normal" pharmacokinetics were observed for the latter, suggesting a saturable "deep compartment." The administration of 4-hydroxycoumarins (i.e., acenocoumarol, phenprocoumon and warfarin) after the microdose of [14C]warfarin was in its beta-phase caused a rapid rise of plasma [14C]warfarin indicating [14C]warfarin to be displaced from the "deep compartment." The rate of appearance of [14C]warfarin was 0.3 hr-1 irrespective the 4-hydroxycoumarin used. The hepatic distribution of [14C]warfarin was investigated and the effect of a displacer thereupon. Fifty-three hours after the [14C]warfarin administration, the liver contained about 40% of the dose; 45% of it was bound to microsomes. The administration of acenocoumarol (0.2 mg/kg) at 48 hr, halved the liver content. [14C]warfarin was redistributed from microsomes (-65%) and from the 10,000 X g pellet (-65%) into the cytosol (+260%) and the plasma (+320%). Microsomal bound [14C]warfarin in vitro could not be washed out or be displaced unless dithiothreitol (50 mM) was included in the washing buffers.(ABSTRACT TRUNCATED AT 250 WORDS)

The solitary rectal ulcer syndrome: diagnosis with defecography

Abstract: The solitary rectal ulcer syndrome is an uncommon entity consisting of a rectal abnormality caused by straining during defecation and characterized by specific histologic changes. Endoscopy may show single or multiple ulcers or a preulcerative phase consisting of mucosal thickening. Findings on barium enema may be normal or nonspecific, consisting of a thickened valve of Houston, nodularity, and rectal stricture. Pathologic changes consist of replacement of the lamina propria by fibroblasts and smooth muscle fibers with marked hypertrophy of the muscularis mucosae. In five patients with histologically proved solitary rectal ulcer syndrome, defecography was performed to evaluate the accompanying defecation disorder. Two patients showed the spastic pelvic floor syndrome, characterized by failure of relaxation of the pelvic floor musculature during straining. In the remaining three, defecography showed an infolding of the rectal wall toward the rectal lumen increasing gradually to form an intussusception. Th...