Showing papers by "Erasmus University Rotterdam published in 1986"

Anatomical and physiological observations on supraspinal control of bladder and urethral sphincter muscles in the cat.

Abstract: In 15 cats injections of 3H-leucine were made in the pontine tegmentum. Injections in the medial part of the dorsolateral pontine tegmentum (M-region) resulted in specific projections to the sacral intermediomedial and intermediolateral cell groups. The intermediolateral cell group contains preganglionic parasympathetic neurons that form the motor supply of the detrusor muscle of the bladder. Injections in the lateral part of the pontine tegmental field (L-region) produced labeled fibers in the nucleus of Onuf, which contains motoneurons innervating the pelvic floor including the anal and urethral sphincters. L-region projections to the sacral preganglionic parasympathetic neurons and M-region projections to the nucleus of Onuf were very limited or absent. In 12 cats physiological experiments were performed. Electrical stimulation in the L-region elicited a prompt increase in the pelvic floor EMG and urethral pressure but had little influence on the intravesical pressure. Stimulation in the M-region elicited a prompt decrease in the pelvic floor EMG and urethral pressure followed, after a delay of 2 seconds, by an increase in the intravesical pressure, so simulating normal micturition.

Tumour microcirculation as a target for hyperthermia

Abstract: A great number of investigators have, independently, shown that tumour blood flow is affected by a hyperthermic treatment to a larger extent than normal tissue blood flow. While the majority of the studies on experimental tumours show a decrease and even a lapse in blood flow within the microcirculation during or after hyperthermia, the data on human tumours are less conclusive. Some of the investigators do not find a decrease in circulation, while others do. Obviously, this is an important field of investigation in the clinical application of hyperthermia because a shut down of the circulation would not only facilitate tumour heating (by reducing venous outflow, this reducing the 'heat clearance' from the tumour), but would also facilitate tumour cell destruction. The same holds for alterations that occur subsequently to the circulatory changes, like a heat-induced decrease of tissue pO2 and pH. If the frequently reported circulatory collapse of the tumour circulation could selectively be stimulated by, e.g. acidification or by vasoactive agents, hyperthermic treatment of patients would possibly be greatly facilitated and intensified. In hyperthermic tumour therapy a number of complex processes and interactions takes place, especially when the treatment is performed in combination with radiation therapy. One of them represents the group of processes related to the random probability of cell sterilization of individual tumour cells resulting in exponential survival curves which are typically evaluated with e.g. cell survival assays. This aspect has not been the issue of this paper. The other group of processes deals with the heat-induced changes in the micro-physiology of tumours and normal tissues which, as discussed before, may not only enhance the exponential cell kill, but which may also culminate in vascular collapse with the ensuing necrosis of the tumour tissue in the areas affected. If this takes place, a process of bulk killing of tumour cells results, rather than the random type of cell sterilization. At present it is not clear to what extent the various separate mechanisms contribute to the total effect of tumour control. With all these considerations in mind, one should be aware of the fact that effects, secondary to heat-induced vascular stasis alone will never be efficient enough to eliminate all tumour cells, even though a heat reservoir is created. This is so because some malignant cells will inevitably have already infiltrated normal, surrounding structures and will therefore not be affected by changes in the tumour vascular bed.(ABSTRACT TRUNCATED AT 400 WORDS)

Linking propositions

Abstract: The function words of a language provide explicit information about how propositions are to be related. We have examined a subset of these function words, namely the subordinating conjunctions which link propositions within a sentence, using sentences taken from corpora stored on magnetic tape. On the basis of this analysis, a computer program for Dutch language generation and comprehension has been extended to deal with the subordinating conjunctions. We present an overview of the underlying dimensions that were used in describing the semantics and pragmatics of the Dutch subordinating conjunctions. We propose a Universal set of Linking Dimensions, sufficient to specify the subordinating conjunctions in any language. This ULD is a first proposal for the representation required for a computer program to understand or translate the subordinating conjunctions of any natural language.

Hu-ets-1 and Hu-ets-2 genes are transposed in acute leukemias with (4;11) and 8;21) translocations

Abstract: Human probes identifying the cellular homologs of the v-ets gene, Hu-ets-1 and Hu-ets-2, and two panels of rodent-human cell hybrids were used to study specific translocations occurring in acute leukemias. The human ets-1 gene was found to translocate from chromosome 11 to 4 in the t(4;11)(q21;23), a translocation characteristic of a subtype of leukemia that represents the expansion of a myeloid/lymphoid precursor cell. Similarly, the human ets-2 gene was found to translocate from chromosome 21 to chromosome 8 in the t(8;21)(q22;q22), a nonrandom translocation commonly found in patients with acute myeloid leukemia with morphology M2 (AML-M2). Both translocations are associated with expression different from the expression in normal lymphoid cells of ets genes, raising the possibility that these genes play a role in the pathogenesis of these leukemias.

Androgen-dependent growth regulation of and release of specific protein(s) by the androgen receptor containing human prostate tumor cell line LNCaP.

Abstract: Hormone sensitivity, as indicated by the presence of steroid hormone receptors and by the effect of androgens and anti-androgens on the release of proteins by cultured cells of the human prostate tumor cell line lymph node carcinoma of the prostate-fast growing colony (LNCaP-FGC), has been studied. The growth of the LNCaP-FGC cells were stimulated by androgens in a dose-dependent way. Under optimal conditions the synthetic nonmetabolizable androgen 17 beta-hydroxy-17 alpha-methyl-(3H)-estra-4,9,11-trien-3-one (R1881) (0.1 nM) stimulated cell growth by approximately 2.3 times. Increasing doses of R1881 (1-100 nM) partly decreased the stimulation of the cell growth. The anti-androgen cyproterone acetate exerted inhibitory effects on cell growth. The nuclear extract of the LNCaP-FGC cells contained 17,000 +/- 2,500 (mean +/- SD) KCl-extractable, nuclear androgen receptor sites/cell. Estrogen and progesterone receptors were not detectable in the nuclear extracts nor in cytosol, indicating that these receptors were absent. The release of proteins in the culture medium was studied using incorporation of the 35S-methionine, sodium dodecyl sulfate (SDS)-gel electrophoresis, and fluorography. Cells grown in media containing charcoal-stripped fetal calf serum released significantly lower amounts of a protein with an apparent molecular mass of 42,000 daltons. The release of this 42-kD protein could be restored in cells cultured in the presence of 5 alpha-dihydrotestosterone (0.1-1 microM) or R1881 (0.1-100 nM), whereas the addition of estrogens or corticosteroids had no effect. In the presence of anti-androgens, such as cyproterone acetate and 5,5-dimethyl-3-(4-nitro-3-(trifluoro-methyl)-phenyl)-2,4-imidasolidin edione, inhibitory effects on the release of the 42-kD protein were observed. The observed parallel between the effects of (anti)-androgens on the growth of the LNCaP prostate cells and the release of the 42-kD protein suggests that this protein is involved in the regulation of malignant prostate cell growth.

Psychosocial aspects of childhood cancer: a review of the literature*

Abstract: The literature concerning the psychosocial aspects of childhood cancer is reviewed. The emphasis of the literature is on the impact of the disease on the child and family and depicts the life-situation when faced with childhood cancer and responses to the disease. The literature strongly indicates that families experience serious difficulties and are a population at risk of developing psychosocial problems. The approach of studying the child with cancer and family is discussed and suggestions are made for future research.

Short-term use of cyclosporin A in severe psoriasis.

Abstract: SUMMARY The effectiveness of cyclosporin A (CyA) in low dosages (mean 5 mg/kg/day) for short-term treatment of severe psoriasis was studied. Of five patients with severe progressive psoriasis vulgaris (mean PASI score 43.8), an almost complete remission in three patients, and a large reduction in PASI score in the remaining two patients, was obtained within 4 weeks. No important clinical side-effects were found but there was biochemical evidence of slight renal dysfunction in one patient. The mean percentage reduction in the PASI score was 84%. It was concluded that the results reported justify further study of the use of CyA in the treatment of severe psoriasis.

Improvement of cardiac output estimation by the thermodilution method during mechanical ventilation.

Abstract: The reliability of cardiac output estimation by thermodilution during artificial ventilation was studied in anesthetized pigs at the right side of the heart. The estimates exhibited a cyclic modulation related to the ventilation. The amplitude of the modulation was independent of the level of positive end-expiratory pressure, ventilatory pattern and volemic loading of the animals. However, a non-constant phase relation existed between the ventilatory cycle and the modulation. Single observations at a fixed moment in the ventilatory cycle are therefore not appropriate for estimation of mean cardiac output nor for studying its relative changes. The averaging of estimates spread equally over the ventilatory cycle led to a much larger reduction in the deviation of the averages from the mean cardiac output than an averaging procedure of randomly selected estimates. The accracy of estimation of mean cardiac output by two estimates equally spread in the ventilatory cycle was equal to the accuracy obtained by averaging five randomly selected estimates. Averaging four estimates, equally spread in the cycle, appeared to be the optimal procedure. For 89% of all averages an accuracy of 5% around the mean was obtained and for 99% an accuracy of ±10%.

Noncontraceptive hormones and rheumatoid arthritis in perimenopausal and postmenopausal women.

Abstract: The use of noncontraceptive hormones before onset of joint disease was compared between 490 perimenopausal and postmenopausal women with rheumatoid arthritis and a control group of 659 women with soft-tissue rheumatologic disorders and/or osteoarthritis. Both groups were sampled randomly from the attendees of five rheumatologic clinics. A negative association was found between the onset of rheumatoid arthritis and the previous use of noncontraceptive hormones (odds ratio, 0.32; 95% confidence interval, 0.16 to 0.64). This association persisted on univariate and multivariate control of potentially confounding variables and on subgroup analysis. The protective effect of oral contraceptives on the development of rheumatoid arthritis was confirmed. ( JAMA 1986;255:1299-1303)

Psychosocial aspects of head and neck cancer–a review of the literature

Abstract: This study is a systematic analysis of the literature on psychosocial aspects in head and neck cancer patients. Patients with head and neck cancer experience a variety of physical as well as psychosocial problems. Physical problems include swallowing or chewing, speech and physical appearance. Psychosocial problems include anxiety, depression, loss of self-esteem and uncertainty about the future. Because of these problems, isolation from friends typically occurs, re-employment is difficult, and there are social and sexual tensions within families. Information and support by professionals, partners and/or fellow patients are related to positive rehabilitation outcomes such as the acquisition of speech, increases in constructive social functioning and decreases in depression.

Childhood leukemia and infectious diseases in the first year of life: a register-based case-control study

Abstract: In the Netherlands, a nationwide register of children with leukemia formed the basis for a case-control study (1973-1980). Population controls were matched with the cases for the year of birth, sex, and place of residence at the time of diagnosis. The information was collected by mailed questionnaires addressed to the parents. The analyses concerned infectious diseases in the first year of life of children with acute lymphocytic leukemia and their controls. Common colds, periods of fever, and primary childhood infections showed relative risks (RR) of 0.8, 0.9, and 0.8, respectively, after adjustment for birth order, family size, social class, and residential space. Furthermore, fewer cases reported infectious diseases which required hospitalization in their first year of life (RR = 0.6, 95% confidence interval (CI) = 0.4-1.0). The general infection risk profile of children with acute lymphocytic leukemia is compatible with these findings: there were more first-born children among the patients (RR = 1.8; 95% CI = 1.1-2.7), more children from one-child families (RR = 1.4; 95% CI = 0.8-2.3), more children of parents with higher education (RR = 1.2; 95% CI = 0.9-1.5), and more rooms in patient's houses (RR = 1.4; 95% CI = 0.6-2.6).

Nifedipine: Kinetics and hemodynamic effects in patients with liver cirrhosis after intravenous and oral administration

Abstract: The pharmacokinetics and hemodynamic effects of nifedipine were studied in patients with liver cirrhosis and in age-matched healthy control subjects. In a randomized order each subject received nifedipine by intravenous infusion (4.5 mg in 45 minutes) and as a tablet (20 mg). After intravenous nifedipine patients had a longer elimination t1/2 (420 +/- 254 vs. 111 +/- 22 minutes; P less than 0.01), a greater volume of distribution (1.29 +/- 0.60 vs. 0.97 +/- 0.42 L/kg), and a lower systemic clearance (233 +/- 109 vs. 588 +/- 140 ml/min; P less than 0.001). Plasma protein binding of nifedipine was lower in the patients (P less than 0.001). After oral nifedipine systemic availability was much higher in patients (90.5% +/- 26.2% vs. 51.1% +/- 17.1%; P less than 0.01) and maximal in patients with a portacaval shunt. Blood pressure decreased and heart rate increased after intravenous nifedipine and these effects could be fitted to plasma concentrations by a sigmoidal model. Maximal effects on heart rate and diastolic blood pressure were not different in liver cirrhosis. When free drug levels were considered, the concentrations corresponding to half the maximal effect were also not different. Blood pressure changes with oral nifedipine were comparable with those after intravenous infusion. We conclude that in patients with liver cirrhosis the pharmacokinetics of nifedipine are considerably altered; dose reduction is recommended when such patients need oral nifedipine.

Wood-related occupations, wood dust exposure, and sinonasal cancer.

Abstract: A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.