Showing papers by "Maastricht University published in 1986"

Myocardial function in normal and spontaneously hypertensive rats during reperfusion after a period of global ischaemia

Abstract: Isolated working hearts of 16 month old spontaneously hypertensive rats (SHR, n=8) and age matched Wistar-Kyoto (WKY, n=8) rats were exposed to 30 min global normothermic ischaemia followed by 60 min reperfusion. The hearts were routinely perfused at an afterload level of 13.3 kPa and a preload level of 1.0 kPa. The control values of left ventricular pressure, its maximal positive first derivative (dPlv/dtmax), coronary flow per gram heart tissue, and release of lactate and enzymes such as lactate dehydrogenase and aspartate aminotransferase were comparable in both groups. WKY rat hearts ejected almost twice as much perfusate per gram heart weight as the SHR hearts. In pressure-flow curves, obtained during the control period in SHR hearts, cardiac output was independent of changes in afterload, varying between 10.7 and 18.7 kPa. In contrast, in WKY rat hearts increases in afterload resulted in a progressive decrease in cardiac output. Reperfusion of the SHR hearts after 30 min of global normothermic ischaemia resulted in a poor recovery of cardiac output (13% of the control values) and dPlv/dtmax (32%) compared with the values in the WKY rat hearts (66% and 91% of the control values respectively). Reactive hyperaemia was prominent in the WKY rat hearts but completely absent in the SHR hearts. During one hour reperfusion, SHR hearts lost 3.5 times more lactate dehydrogenase and 2.5 times more aspartate aminotransferase than the WKY rat hearts. Pressure-flow curves, obtained during the reperfusion period, showed modest recovery of myocardial function of the WKY rat hearts at the lowest afterload level tested but completely depressed myocardial function of the SHR hearts at all afterload levels. Heart tissue contents of adenosine triphosphate and creatine phosphate after one hour of reperfusion were lower in the SHR than in the WKY rats, but compared with native values a comparable percentage decrease was seen in both groups of rats.

Patterns of basement membrane deposition in benign and malignant breast tumours.

Abstract: We have examined epithelial basement membranes in tissue samples of seven normal breasts, 64 benign breast lesions and 63 malignant breast tumours by immunocytochemistry, using polyclonal antisera specific for type IV collagen. In normal breast tissue as well as in all benign tumours a continuous basement membrane was found at the epithelial stromal interface. In benign proliferative lesions, epitheliosis and papillomatosis could be more accurately distinguished with basement membrane staining. This approach also facilitated the differentiation between sclerosing adenosis and tubular carcinoma, since the tubules in sclerosing adenosis are surrounded by a continuous basement membrane whereas in tubular carcinoma basement membranes are almost entirely absent. In radial scar lesions the tubules were always surrounded by intact basement membranes, which underlines the fact that these are benign lesions. In breast carcinoma we could not detect a relationship between histological grade and the extent of basement membrane deposition. However, in different tumour types the basement membrane alterations varied. In infiltrating lobular carcinoma of the alveolar type, fragments of basement membrane were found, whereas in the classic and trabecular type, basement membranes were absent, suggesting that the alveolar type may be an intermediate phase in the progression of lobular carcinoma in situ to infiltrating lobular carcinoma. It is concluded that basement membrane immunocytochemistry, using antibodies to type IV collagen, is useful in the differentiation between benign and malignant breast lesions and in the classification of breast neoplasms.

Joint report of the Third International Workshop on Canine Immunogenetics. I. Analysis of homozygous typing cells.

Abstract: The Third International Workshop on Canine Immunogenetics involved 80 potentially DLA-D homozygous typing cells obtained from dogs of various breeds and submitted from five laboratories in Europe and the United States. Mutual reactivity of all cells was studied in mixed leukocyte cultures, and stabilized relative responses were used for analysis. Intralaboratory and interlaboratory comparisons of results suggest that a stabilized relative response of 30% represents an acceptable parameter for "typing responses" indicating phenotypic DLA-D identity of stimulator and responder cells. Using this criterion, 10 clusters of homozygous typing cells were defined and accepted on an international level, and they were assigned the specificities Dw1 to Dw10. At least six additional (provisional) specificities were recognized that were well characterized within individual laboratories but require additional testing before workshop specificities can be assigned. These data show that DLA-D typing is feasible and represents a useful tool in the genetic analysis of the canine major histocompatibility complex. Much work is needed to confirm the present results in family studies, to determine gene frequencies, and to analyze at a molecular level the antigens responsible for mixed leukocyte culture reactivity.

The role of genetically-determined primary alterations of the target organ in the development of spontaneous autoimmune thyroiditis in obese strain (OS) chickens.

Abstract: Immunologists working in the field of autoimmunity tend to concentrate all their efforts on the elucidation of possible malfunctions of the immune system, particularly pathologic changes of immune regulation. Also in the OS model various groups of investigators emphasized this approach, although it was already clear early in the history of this model that SAT has a multigenic background. The fact that this disease cannot be transferred into normal, histocompatible animals without an appropriate non-MHC linked genetic background was a strong indication that detailed studies of thyroid-associated factors may be warranted for the elucidation of the pathogenesis of this disease and perhaps also its human counterpart, Hashimoto thyroiditis. Since several reviews on the immunologic aspects in the OS model have been published in recent years we have in this communication attempted to discuss the - mostly still rudimentary - findings concerning the target organ itself, including morphological changes before the beginning of infiltration, the analysis of Tg, the altered thyroid function before onset of SAT, the results of cross-breeding studies of OS and inbred normal chickens in respect to the susceptibility of the offspring for the transfer of SAT, the possible role of a virus infection and the aberrant expression of MHC class II antigens on TEC. Cross-breeding studies revealed that most probably a single gene is responsible for the primary altered thyroid function and at least 3 genes code for the susceptibility of the OS thyroid gland to the autoimmune attack. It is not yet clear for which of the above-mentioned observations each of these genes is responsible and what is/are the initial triggering mechanism(s). Ongoing studies in our laboratory concentrate on this question, specifically the potential role of endogenous viruses in this process.

The occurrence and clinicopathological significance of serotonin immunoreactive cells in large bowel carcinoma.

Abstract: We studied the incidence, clinicopathological relevance and prognostic significance of serotonin immunoreactive cells in a clinically well-documented series of 300 large bowel cancer patients. Serotonin immunoreactive cells were detected in 8 per cent of the carcinomas, occurring either as focal clusters (4.7 per cent) or as occasional single cells (3.3 per cent). Both types frequently displayed presence of mucin and/or immunoreactivity for secretory component as well. In respect of localization, stage of tumour extension and histological grade tumours with serotonin immunoreactivity showed no significant differences in comparison with carcinomas lacking this feature. In terms of survival, however, the tumours with serotonin immunoreactivity demonstrated a more aggressive clinical course in comparison with tumours without these cells. This phenomenon reached borderline statistical significance. It is therefore concluded that the study of serotonin immunoreactivity in large bowel carcinomas enables the identification of a subpopulation of colorectal carcinomas with a relatively poor prognosis.

Influence of physical exercise on the pharmacokinetics of propranolol.

Abstract: The pharmacokinetics of propranolol after oral and intravenous administration was studied at rest and on an exercise day in 8 healthy subjects. On the exercise day the subjects performed physical exercise for 7 h, consisting of bicycle ergometer exercise at 50% of maximal work capacity and outdoor walking. Propranolol (80 mg p.o., or 0.2 mg/kg body weight i.v.) was administered 30 min before the start of the exercise. After oral administration the terminal phase halflife, (t1/2 beta) and area under the curve (AUC) were both significantly reduced on the exercise day compared to the rest day. The bioavailability of propranolol was reduced by prolonged physical exercise and plasma levels of propranolol were about 30% lower at the end of the exercise day than at the end of the rest day. After intravenous administration, t1/2 beta was also reduced on the exercise day as compared to the rest day. AUC, clearance and volume of distribution did not differ on the two days. On the other hand, indocyanine green (ICG) clearance was significantly reduced during the bicycle ergometry periods on the exercise day. The combination of reduced ICG clearance, suggesting a reduction in hepatic blood flow, and a decreased t1/2 beta and unchanged clearance of propranolol on the exercise day was unexpected.

Neuroendocrine cells in colorectal adenomas.

Abstract: A consecutive series of 218 endoscopically resected colorectal adenomas was investigated for the occurrence of neuroendocrine cells. In 59 per cent of these adenomas argyrophil cells were detected. In 8 per cent of the adenomas these cells were numerous and so intricately blended in with the other cell types that they were regarded as an intrinsic part of the tumour. In these adenomas subsequently immunocytochemistry revealed the presence of the neuro-hormonal peptides glucagon, pancreatic polypeptide and somatostatin as well as serotonin, in a pattern similar to that seen in normal colorectal mucosa. The presence of neuroendocrine cells did not correlate with any clinical or pathological parameter. The occurrence of neuroendocrine cells in colorectal adenomas is in agreement with the unitarian theory of the development of the various epithelial cell types in large bowel mucosa.

Determination of steroid hormone-dependency of tumours utilizing tissue sections. Survey of histochemical techniques and their application in surgical pathology.

Abstract: The growth of neoplasms originating from steroid hormone target tissues may be hormone-dependent. It has been clearly demonstrated that the oestrogen and/or progestagen receptor status predicts the response to endocrine treatment and the prognosis of breast cancer. However steroid receptor determination in tumour cytosols has several limitations, which can partly be resolved by (immuno) histochemical detection of steroid hormone-responsive tumour cells. A variety of histochemical techniques including autoradiography of tritiated steroids, immunohistochemistry with antibodies to steroid hormones, histochemistry with fluorescent ligands of low molecular weight and fluorochrome- or enzyme-labelled macromolecular probes are discussed. It is concluded that there is as yet no substantial evidence that these methods visualize steroid receptors or detect steroid hormone-responsiveness of tumour cells. On the other hand, immunohistochemical demonstration of oestrogen receptors with monospecific antibodies seems validated and indications have been obtained that this information is clinically relevant. Recent developments suggest that immunocytochemistry of receptors and specific hormone-induced proteins, flow cytometric analysis and probably hybridocytochemistry in the future will help to improve management of steroid hormone-dependent tumours.

Methods to measure blood flow velocity of red blood cells in vivo at the microscopic level.

Abstract: Several methods to measure red blood cell velocity in microvessels by electronic means are discussed. Signals are generated by the red blood cells present in the microscopic image of the microvessels. These signals can be converted to obtain an output signal proportional to the actual red blood cell velocity. The method of spatial filtering by interlacing gratings is discussed in terms of a filter with an input signal. Adaptation of optical factors that might improve the velocity measurement is obtained by a mathematical analysis. Different methods of correlation are presented. The temporal correlation (dual slit and video window) and spatial correlation methods are discussed in relation to factors influencing the quality of the correlogram, the peak of which is proportional to red blood cell velocity. The conversion of red blood cell velocity to volume flow is put in perspective.

The effect of verapamil on cardiovascular and metabolic responses to exercise

Abstract: In a double-blind cross-over study, the effects of verapamil on the cardiovascular and metabolic changes during a progressive maximal exercise test were studied in 12 healthy volunteers. Each subject was treated with placebo and verapamil in 3 different dosages: 3×40, 3×80 and 3×120 mg · d−1 in random order. Drugs were administered for 2 days; on the 3rd day, 2 h after the last dose, a progressive exercise test until exhaustion was performed on a bicycle ergometer. No significant differences in maximal exercise capacity were found between the 4 groups of medication. \(\dot V_{{\text{O}}_{\text{2}} }\), \(\dot V_{CO_2 }\), and \(\dot V_E \) were also unaffected by verapamil administration. Heart rate during exercise was reduced dose-dependently (p<0.001). With the highest dose of verapamil, maximal heart rate was reduced by 13±1 beats · min−1. No effect could be shown on parameters of carbohydrate and fat metabolism. Perceived exertion, estimated by the Borg scale, did not differ between placebo and the 3 medication groups. The study shows that despite a distinct reduction of heart rate, maximal exercise capacity remains unaffected after verapamil use.

Smoking behaviour of Dutch general practitioners in the period 1977-1983.

Abstract: Between 1977 and 1983 roughly half of the Dutch general practitioners were smokers. The percentage of smokers was decreasing, both among general practitioners and in the general Dutch population. The number of smoking male general practitioners was higher than for men in general and considerably higher than in the highest socioeconomic bracket. Among general practitioners the daily consumption of manufactured and handrolled cigarettes was lower while the cigar consumption was higher. In most countries physician smoking behaviour antedates that of the general population but in Holland general practitioners' smoking habits are about four years behind that of the general population. It seems that Dutch general practitioners attribute little value to the role of setting an example in health behaviour, especially where it concerns their own smoking habits.

Purification of a delayed hypersensitivity-inducing protein from Listeria monocytogenes

Abstract: Cell-envelope fragments were prepared from Listeria monocytogenes L242, serotype 4b. Delayed hypersensitivity (DH)-inducing proteins were extracted with deoxycholate and separated into two fractions by filtration through a Sephacryl S-200 column equilibrated with deoxycholate buffer. The second peak eluting from the Sephacryl column was fractionated using ion exchange chromatography on a DEAE Sepharose CL-6B column in the presence of 6 M urea. A purified 20 400-Da protein which induced DH against L. monocytogenes was obtained by isocratic elution. Three other DH-inducing fractions containing several protein bands were eluted by a gradient of potassium thiocyanate (KSCN) in urea buffer. Our results indicate that denaturing conditions can be employed for the fractionation and purification of DH inducing proteins from L. monocytogenes. In addition, it is suggested that the procedure described might also be useful for the purification of other antigens involved in cellular immune reactions.

Twenty-four hour effects of oxprenolol oros and atenolol on heart rate, blood pressure, exercise tolerance and perceived exertion

Abstract: The effects of oxprenolol, a non-selective beta-blocker with moderate intrinsic sympathomimetic activity (ISA), given by the Oros delivery system, on resting and exercise heart rate and blood pressure have been compared over a 24-h period with those of atenolol, a beta1-selective blocker without ISA. The effects on maximal and submaximal exercise tolerance and perceived exertion were studied in relation to the level of beta-blockade. 9 healthy subjects were treated with placebo, atenolol, 100 mg/day and oxprenolol Oros, 16/260 mg/day in random order, each for 5 days. Progressive maximal exercise tests and submaximal endurance tests at 80% of maximum aerobic exercise capacity were performed 2, 5 and 24 h after intake of the drugs. The reduction of blood pressure 2 and 5 h after drug intake was less pronounced after oxprenolol Oros than after atenolol, but by 24 h after the last dose the effects were similar. The peak level of beta-blockade (i.e. reduction in maximal exercise heart rate) was similar after oxprenolol Oros and atenolol. The minimal level of beta-blockade 24 h after the last dose was greater after oxprenolol Oros than after atenolol. Maximal exercise capacity and submaximal exercise tolerance were impaired after both beta-blockers. The subjective feeling of exertion did not differ between placebo, atenolol and oxprenolol Oros when related to the relative work load, except after the first minute of exercise, when the rating of perceived exertion was higher after atenolol.

γ-Glutamyl Carboxylase Activity in Experimental Tumor Tissues: A Biochemical Basis for Vitamin K Dependence of Cancer Procoagulant

Abstract: Rabbit V2 carcinoma tissues have been described to possess a procoagulant activity with specific characteristics; this material has been purified and identified as a cysteine proteinase able to directly activate coagulation factor X. We have shown here that the procoagulant activity of V2 carcinoma extracts is depressed in warfarin-treated animals, thus suggesting that cancer procoagulant could represent a new vitamin K-dependent protein. The biochemical basis for this effect is offered by the identification of γ-glutamyl carboxylase in the microsomal fraction of tumor tissues. The V2 carcinoma has a carboxylase activity which is increased in warfarin-treated animals. An endogenous substrate of tumor carboxylase, the nature of which has not been identified, has been found 5-fold increased in warfarin-treated animals. The presence of γ-glutamyl carboxylase was also described in several murine tumors including both carcinomas and fibrosarcomas. It is worth mentioning that all the tumors tested produce a procoagulant with the peculiar characteristics of that described in V2 carcinoma. It is conceivable that cancer procoagulant could represent at least one of the substrates for γ-glutamyl carboxylase in these experimental tumor tissues.

Alterations of the functional state of peritoneal macrophages during rat cytomegalovirus infection in vivo

Abstract: The effect of intraperitoneal (i.p.) infection with rat cytomegalovirus on the effector functions of peritoneal macrophages was investigated. There was an influx of polymorphonuclear leukocytes into the peritoneum on day 1 followed by an influx of macrophages on day 4. The macrophages harvested on day 4 showed enhanced levels of chemiluminescence emitted during phagocytosis of zymozan particles, and enhanced capacity to kill Staphylococcus aureus . Thereafter, the chemiluminescence level and the bactericidal capacity decreased, remaining low up to 6 months post-infection. In addition, macrophages harvested from animals on day 7 showed increased phagocytosis of sheep red blood cells.