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Biomedical subjects

B Kemp

Publications and source records attributed to B Kemp.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Continued driving habits of patients diagnosed with excessive daytime sleepiness].

OBJECTIVE: Description of driving behaviour of patients with excessive daytime sleepiness (EDS) and the influence on their driving of diagnosis, therapy, legal guidelines and advices. DESIGN: Inventory based on questionnaires. SETTING: Centre for Sleep and Wake Disorders, The Hague, the Netherlands. METHODS: All patients with EDS who were in a stable condition for at least 6 months after therapy were sent a questionnaire (n = 138). The questions concerned actual driving behaviour, EDS and the effects of diagnosis, therapy and advice given by the Centre. RESULTS: The response was 67% (n = 92). Eighteen patients had never driven a car. Eighteen of the other 74 patients quit driving or drove less. Fifty-six patients did not change their behaviour or drove even more. There was little effect on driving behaviour of diagnosis, therapy and advice to stop driving. CONCLUSION: Patients with EDS often participate as drivers in modern traffic. Legal guidelines and advice given by physicians have only little influence on this behaviour. As general measures seem to be ineffective, approaches tailored to the individual patient may lead to more acceptable results.

Adolescent↗
PubMed1998

Ontogenesis of the sperm whale brain.

The development of the sperm whale brain (Physeter macrocephalus) was investigated in 12 embryos and early fetuses to obtain a better understanding of the morphological and physiological adaptations in this most exotic cetacean concerning locomotion, deep diving, and orientation. In male adult sperm whales, the average absolute brain mass and the relative size of the telencephalic hemisphere are the largest within the mammalia, whereas the ratio of the brain mass to the total body mass is one of the smallest. In the early sperm whale fetus, the rostral part of the olfactory system (olfactory nerves and bulbs) is lost, whereas the nervus terminalis seems to persist. Several components of the limbic system show signs of regression (hippocampus, fornix, mamillary body). In contrast, some components of the auditory system (trapezoid body, inferior colliculus) show marked enlargement in the early fetal period, thereby reflecting their dominant position in the adult. The cerebellum and pons grow slower than in most smaller toothed whales. The pyramidal tract develops poorly (reduction of the limbs), whereas marked growth of the striatum and inferior olive may be related to the animal's locomotion via trunk and tail. In the early fetal period, the trigeminal, vestibulocochlear, and facial nerves are the dominant cranial nerves (besides the vagus nerve). Whereas the number of axons in the vestibulocochlear nerve is high in adult, toothed whales and their diameters are considerable, the trigeminal nerve of the sperm whale may be the thickest of all cranial nerves and has the largest number of axons (innervation of the huge forehead region). A similar situation seems to exist for the facial nerve: It innervates the blowhole musculature that surrounds the very large spermaceti organ and melon (generation and emission of sonar clicks).

Animals↗
PubMed1998

Noninvasive diagnosis of oral neoplasia based on fluorescence spectroscopy and native tissue autofluorescence.

OBJECTIVE: To evaluate the clinical potential of fluorescence spectroscopy (a noninvasive technique for assessing the chemical and morphologic composition of tissue) for in vivo detection of oral cavity neoplasia. DESIGN: A fluorescence spectroscopy system recorded spectra from oral cavity sites in 8 healthy volunteers and in 15 patients with premalignant or malignant oral cavity lesions at 337-, 365-, and 410-nm excitation wavelengths in the emission range of 350 to 700 nm. Fluorescence peak intensities and spectral line shapes were compared and diagnostic algorithms were developed to distinguish normal sites from abnormal sites. SETTING: The head and neck cancer clinic at a tertiary referral center in Houston, Tex. RESULTS: Differences were found in spectra from normal, dysplastic, and malignant oral mucosa. The fluorescence intensity of normal mucosa was greater than that of abnormal areas. In addition, the ratio of red region (635-nm) to blue region (455-490-nm) intensities was greater in abnormal areas. Diagnostic discrimination was achieved when test site spectra were compared with spectra from a normal site in the same patient. One diagnostic algorithm based on spectra at 337 nm gave a sensitivity of 88% and a specificity of 100%. CONCLUSIONS: Consistent differences exist between the fluorescence spectra of abnormal and normal oral mucosa. Therefore, fluorescence spectroscopy has the potential to improve the noninvasive diagnosis of oral cavity neoplasia. Further studies will better define the role of this technique in the detection of premalignant and early oral cancer lesions.

Adult↗
PubMed1998

Expression of cell adhesion molecules by endothelium in the human lower uterine segment during parturition at term.

OBJECTIVE: Our purpose was to determine whether the expression of certain adhesion molecules by endothelium in the human lower uterine segment at term varies with the degree of cervical dilatation. STUDY DESIGN: Biopsy specimens of the lower uterine segment of 34 women undergoing cesarean section at term at various stages of cervical dilatation were immunostained for endothelial leukocyte adhesion molecule-1, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and platelet-endothelial cell adhesion molecule. RESULTS: The expression of endothelial leukocyte adhesion molecule-1 was significantly greater at more than 6 cm dilatation than at less than 2 cm (p = 0.00031) as was that of vascular cell adhesion molecule-1 (p = 0.033). Expression of intercellular adhesion molecule-1 and platelet-endothelial cell adhesion molecule did not vary with the degree of cervical dilatation. CONCLUSION: Cervical dilatation is associated with up-regulation of certain endothelial cell adhesion molecules. The findings support the hypothesis that certain processes associated with cervical dilatation at term resemble those involved in the acute inflammatory reaction.

Cervix Uteri↗
PubMed1998

Digital archival and exchange of events in a simple format for polygraphic recordings with application in event related potential studies.

This paper describes a simple method of event encoding as an extension to a previously defined standard format, the European Data Format (EDF). The specification ensures full backward compatibility with the existing definition. By using this extension, the format can be used to store both continuous recordings and selected epochs of recordings. The encoding is performed in a channel of event-codes or in a pseudo-channel for annotations. Standardisation of event encoding is discussed. Decoding of events or annotations from the extended format is implemented at the application level. Existing programs that do not support the new encoding scheme still operate correctly and can simply ignore the new channels in processing 'extended' data files. The event encoding is also compatible with EDF's capability to encode channels of different sampling frequency.

Data Interpretation, Statistical↗
PubMed1998

The validity of the Dutch Sleep Disorders Questionnaire (SDQ).

The Sleep Disorders Questionnaire (SDQ) is a 176-item questionnaire designed to diagnose the presence of common sleep disorders. This study set out to assess the validity of a Dutch translation of the SDQ. Scores on 145 questionnaires were analyzed. A cluster analysis of these scores revealed the following clusters: healthy, depression, insomnia, narcolepsy, and apnea. The cluster classification proved correct for 67% of the subjects, as determined on the basis of polysomnography. These results show that the Dutch SDQ is a reasonably valid instrument for diagnosing sleep disorders.

Adolescent↗
PubMed1998

Influence of linoleic/linolenic acid ratio in the diet of periparturient cattle on plasma concentrations of PGF2 alpha metabolite and placental expulsion rate.

Forty-eight cows Holstein Friesian x Dutch Friesian (HF x DF) were randomly assigned to 2 groups fed 1 of 2 diets (isocaloric and isonitrogenous but different in linoleic/linolenic acid ratio) from 4 wk before expected parturition until 7 d after calving. Effects of the diet on plasma linoleic/linolenic acid ratio, plasma PGFM levels and placental explusion rate were studied. Dietary treatment resulted in significant differences in linoleic/linolenic acid ratio in blood plasma (1.00 +/- .22 vs 4.41 +/- .53). The placental expulsion rate was not significantly different between the 2 treatment groups. Plasma PGFM levels, as analyzed for 28 cows from 30 d before parturition until 1.5 d after parturition, were similar for the diets. Cows with a longer placental expulsion rate had lower PGFM levels at parturition (for instance, placental expulsion rate shorter (n = 11) and longer (n = 17) than 6 h, 1248 vs 2965 pg/ml, residual standard deviation 1185 pg/ml, P < 0.01). The results show that the dietary linoleic/linolenic acid ratio can influence the plasma linoleic/linolenic acid ratio without affecting the placental expulsion rate or plasma PGFM levels around parturition.

Animals↗
PubMed1998

Body position can be monitored in 3D using miniature accelerometers and earth-magnetic field sensors.

OBJECTIVES: The study and diagnosis of movement disorders can be improved by monitoring body position simultaneously with the EMG. METHODS: We developed a monitor of the 3-dimensional (3D) orientation of body parts that can be applied in long-term ambulatory recordings in the daily life of a patient. The 3D sensor combines miniature sensors for earth's gravity and magnetism. It measures 60 x 50 x 10 mm and draws less than 1 mA of current from +/-5 V battery power. The non-horizontal direction of earth magnetism, as well as torque (pronation) of the body part, is corrected mathematically. RESULTS: This results in a measurement of the 3D orientation of a body part in terms of vertical inclination and horizontal azimuth. CONCLUSIONS: Calibration measurements indicate that this method is fairly accurate and practically applicable.

Acceleration↗
PubMed1998

The prevalence of clinically significant sleep apnoea syndrome in The Netherlands.

BACKGROUND: Figures for the prevalence of sleep apnoea syndrome range from 0.3% to 8.5%. These widely ranged estimates are probably due to differences in the definitions used, study designs, and study populations. A study was undertaken to determine the lower limit of the prevalence of clinically significant sleep apnoea syndrome. METHODS: A cross sectional survey by postal questionnaire was carried out in a general practice of a small town in which three doctors serve 93% of its population of 6747 inhabitants of all ages. All men aged 35 and over and women aged 50 and over were invited to fill in a specially designed questionnaire on snoring and sleep. All men and women whose answers suggested the possible occurrence of sleep apnoea were invited to undergo further investigation. Oronasal thermistry was performed in the subjects' homes and the results were scored to provide an apnoea index (AI). Those subjects with an AI of > or = 5 were referred to a sleep laboratory for investigation by polysomnography. RESULTS: Of the 2466 questionnaires issued, 2182 (88.5%) were completed and returned. The occurrence during the previous three months of regular snoring, together with daytime sleepiness and/or partners' observation of interruptions in breathing at night, was reported by 194 subjects (169 men, 25 women). In 173 subjects oronasal thermistry applied in their homes provided satisfactory recordings and, of these, 24 men and one woman had an AI of > or = 5. Analysis of the polysomnographic findings showed that 14 men and one woman met the criteria for sleep apnoea syndrome. Scrutiny of their case records disclosed that in seven men this was clinically significant. CONCLUSIONS: Our findings suggest that the prevalence of clinically significant sleep apnoea syndrome in men aged 35 and over is at least 0.45%. Extrapolation to the population of the Netherlands suggests that at least 16,000 men suffer from sleep apnoea syndrome that should be relieved by medical care. A large proportion of these subjects remains to be diagnosed.

Adult↗
PubMed1998

Cervical dilatation: induction by antigestagens via adhesion molecules. An in vitro examination in endothelial cell cultures.

Cervical ripening at term resembles an inflammatory reaction with invasion of activated granulocytes into the cervical stroma. Our objective was to investigate the influence of the antigestagen onapristone alone and in combination with other substances associated with cervical ripening on the expression of the inflammation-associated adhesion molecules ELAM-1, ICAM-1 and VCAM-1. Human endothelial cell cultures were stimulated with onapristone (200 ng/ml), TNF-alpha (100 U/ml), IL-8 (20 ng/ml) and PGE2 (3 ng/ml) separately and in combination (n = 6). The expression of adhesion molecules was determined qualitatively and quantitatively by immunofluorescence staining and flow cytometry with statistical evaluation by Kolmogorov-Smirnov analysis. Onapristone upregulated slightly the expression of ELAM-1 (19%). The costimulation of onapristone and TNF-alpha provoked an additive expression of VCAM-1 (64%) beyond the effect of TNF-alpha alone, while the costimulation of onapristone and PGE2 as well as the combination with IL-8 did not result in an additional stimulatory effect. All results were statistically significant (p < 0.001). This result supports our hypothesis that onapristone may lead to an increased adhesion of granulocytes to the capillary endothelium thereby initiating cervical ripening.

Cell Adhesion Molecules↗
PubMed1998

The importance of extracellular matrix in the induction of preterm delivery.

Evidence suggests that in the lower uterine segment at term an increased production of tumor necrosis factor (TNF) alpha and interleukin (IL)-1 beta induces an increase in the expression of adhesion molecules by the endothelium. The expression of endothelial-leukocyte adhesion molecule-1 and vascular cell adhesion molecule-1 were found to increase from a cervical dilatation of 2-3 cm and reaches a maximum at cervical dilatation of more than 6 cm. Increased adhesiveness of the endothelium leads to extravasation of neutrophils into the cervical stroma. The chemotaxis and degranulation of these cells is triggered by a rise in the concentration of IL-8 found in the lower uterine segment when cervical dilatation progresses. A significant increase in stroma invasion by neutrophils with progressive cervical dilatation was observed. This finding coincides with a rise in the granulocytic matrix metalloproteinases (MMP)-8 and MMP-9 concentrations up to complete cervical dilatation. We found similar patterns of cytokine concentrations in the lower uterine segment of patients with preterm delivery: at 2-3 cm dilatation the concentrations of IL-1 beta, IL-6- und IL-8 were significantly higher than at less than 2 cm. Concomitantly, we also found an increase in MMP-8, MMP-9 and tissue inhibitor of metalloproteinases-1 concentrations from less than 2 cm to 2-3 cm cervical dilatation. These findings suggest that the changes in the lower uterine segment during preterm parturition seem to be similar to those at term and both resemble an inflammatory process.

Cervix Uteri↗
PubMed1998

[Preoperative determination of the structure of pelvic tumors with color-coded Doppler ultrasound and conventional transvaginal ultrasound diagnosis].

In 265 adnexal masses results of conventional transvaginal sonography and coloured doppler sonography were compared with histopathological results. Statistical evaluation was based on lowest PI and RI as well as highest peak systolic velocity from signals derived of all detectable tumour vessels. Cut-off values from actual literature and cut-off values established in Aachen (PI < 0.69, RI < 0.45) were used. Histopathologic evaluation showed 210 (79.2%) benign and 55 (20.8%) malignant ovarian tumours. A cut-off at < 0.69 for the PI led to a sensitivity of 79.6% and a specificity of 58.2%. For RI sensitivity was 66.7% and specificity was 68.7% at a cut-off at < 0.45. The sonomorphologic evaluation following a scale published by Sassone et al. [20] had a sensitivity of 85.2% and a specificity of 67.1%. There was no statistical significant difference between mean values for peak systolic velocity in benign and malignant tumours. The exclusive evaluation with Doppler sonography leads to a high percentage of misdiagnosis. A combination with sonomorphologic evaluation does not lead to an important improvement of preoperative diagnosis as there is a bright overlap between benign and malignant tumours. In contrast Doppler sonography might add important information in the preoperative evaluation of early ovarian cancer.

Adult↗
PubMed1997

Plasma prolactin, growth hormone and progesterone concentrations in pseudopregnant, hysterectomized and pregnant goats.

Jugular plasma prolactin (PRL), growth hormone (GH) and progesterone (P4) levels were estimated in goats under three different conditions with prolonged luteal function (P4 > or = 1 ng/ml): pseudopregnant animals (n = 4), goats hysterectomized during early pregnancy (n = 4) and does with normal pregnancy (n = 4). Mean duration (+/- S.E.M.) of luteal phases were 189 +/- 20, 171 +/- 10, and 147 +/- 2 days in the three groups, respectively. Until day 120, mean PRL levels were below 150 ng/ml in each group. After day 120 of the luteal phase, PRL concentrations were significantly higher than before, but continued to increase up to 800 ng/ml only in pregnant animals around parturition. Mean GH levels varied between 2 and 3 ng/ml in animals of each group during the luteal phase. Only after parturition, a significant elevation occurred. P4 levels in pseudopregnant animals were significantly lower than in the other two groups between days 10 and 55, and showed a gradual but continuous decline towards the end of the luteal phase. After hysterectomy of early pregnant animals, P4 concentrations decreased to levels measured in pseudopregnant animals but were significantly higher again as compared to pseudopregnant animals between days 121 and 150. It is concluded that a pseudopregnant condition, characterized by intrauterine fluid accumulation, is not related to increased plasma PRL and GH concentrations. The low and gradually decreasing plasma progesterone levels in the pseudopregnant animals probably reflect the absence of a luteotrophic stimulus by the conceptus. The progesterone profile in the animals that were hysterectomized during early pregnancy suggests that the corpora lutea of these does have been permanently changed by the presence of the conceptus during the first weeks of the luteal phase.

Animals↗
PubMed1997

The effect of enforcing tobacco-sales laws on adolescents' access to tobacco and smoking behavior.

BACKGROUND: Enforcing laws banning tobacco sales to minors is widely advocated as a way to reduce young people's access to tobacco and tobacco use. Whether this approach is successful is not known. METHODS: In a two-year controlled study, we assessed sales of tobacco to minors and young people's access to and use of tobacco in six Massachusetts communities. Three communities (the intervention group) enforced tobacco-sales laws, whereas three matched communities (the control group) did not. To assess compliance with the law, minors working for the study investigators attempted to purchase tobacco from all retail vendors in each community every six months. Three annual anonymous surveys of a total of 22,021 students in grades 9 through 12 (response rate, 84 percent) measured access to tobacco and smoking behavior. RESULTS: At base line, 68 percent of 487 vendors sold tobacco to minors. Compliance with the law improved significantly faster in the intervention communities than in the controls (P<0.001). By the study's end, 82 percent of the merchants in the intervention communities complied with the law, as compared with 45 percent in the control communities (P<0.001). However, adolescents under 18 years old reported only a small drop in their ability to purchase tobacco and no decline in its use. Communities with and those without enforcement programs did not differ with respect to these outcomes. CONCLUSIONS: Enforcing tobacco-sales laws improved merchants' compliance and reduced illegal sales to minors but did not alter adolescents' perceived access to tobacco or their smoking. Test purchases of tobacco do not accurately reflect adolescents' self-reported access to tobacco, and reducing illegal sales to less than 20 percent of attempts -- the goal of a new federal law-- may not decrease young people's access to or use of tobacco.

Adolescent↗
PubMed1997

Prophylaxis and treatment of bladder dysfunction after Wertheim-Meigs operation: the positive effect of early postoperative detrusor stimulation using the cholinergic drug betanecholchloride.

The efficacy of betanecholchloride in the postoperative treatment of bladder dysfunction is controversial. We therefore performed a comparative study on the effect of this therapy for the prophylaxis of detrusor hypotonia after Wertheim-Meigs operation. Forty patients with cervical cancer FIGO stage Ib/IIa were divided into two study groups. The control group (24 patients) only received betanecholchloride if the residual urine persisted above 50 ml after the 10th postoperative day. The study group (16 patients) received 50 mg betanecholchloride three times a day from the 3rd postoperative day onward. In this group postoperative catheter treatment, and consequently hospital stay, were significantly shorter (9.6 versus 13.3 days and 15.5 versus 18.6 days). The residual urinary volume normalized faster (8.0 versus 13.0 days) and the rate of cystitis was lower (18.8 versus 25%). According to our study, a prophylactic application of the parasympathomimetic drug betanecholchloride diminishes postoperative complications associated with bladder dysfunction after Wertheim-Meigs operation.

Adult↗
PubMed1997

Pharmacodynamics of temazepam in primary insomnia: assessment of the value of quantitative electroencephalography and saccadic eye movements in predicting improvement of sleep.

BACKGROUND AND OBJECTIVE: Quantitative electroencephalographic parameters and saccadic eye movements are frequently used as pharmacodynamic measures of benzodiazepine effect. We investigated the relationship between these measures and the hypnotic effect. METHODS: The correlation between the pharmacodynamic measures and sleep quality was determined in 21 patients with primary insomnia. The pharmacokinetic-pharmacodynamic relationships were characterized after administration of 20 mg oral temazepam. The hypnotic effect was determined on the basis of polysomnographic sleep recordings and a subjective sleep evaluation questionnaire. Correlations between pharmacodynamic measures and the improvement of sleep were investigated. RESULTS: The pharmacokinetic-pharmacodynamic relationships for the parameters derived from electroencephalography and saccadic eye movements showed considerable interindividual variability. Administration of temazepam led to a significant improvement in the objective parameters sleep period efficiency, wake time after sleep onset, and sleep efficiency and in the subjective assessment of sleep quality. No significant correlations were observed between the pharmacokinetic-pharmacodynamic-derived parameters and the improvement in objective or subjective sleep parameters. CONCLUSION: In subjects with primary insomnia the administration of 20 mg oral temazepam results in changes in both the pharmacodynamic measures and in quality of sleep. No individual correlations between the pharmacodynamic measures and quality of sleep were observed. We concluded that the investigated pharmacodynamic measures are of value in the first assessment of clinical efficacy and for the selection of the dose(s) to be investigated in subsequent trials that aim at showing clinical efficacy. However, the conclusive quantification of clinical efficacy should be performed only on the basis of the clinical end point itself.

Adult↗
PubMed1997

Parturition: steroids, prostaglandin E2, and expression of adhesion molecules by endothelial cells.

OBJECTIVE: To determine whether 17 beta-estradiol, progesterone, and prostaglandin (PG) E2, alone or in combination with cytokines, influence the adhesiveness of vascular endothelium and thus play a role in the first stage of leukocyte infiltration of the uterine cervix during parturition. METHODS: Cultured umbilical vein endothelial cells obtained from 11 women after vaginal delivery at term were incubated with 17 beta-estradiol, progesterone, PGE2, tumor necrosis factor alpha (TNF-alpha), and interleukin-8, (IL-8), alone and in combination. The expression of endothelial leukocyte adhesion molecule-1, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 was investigated by immunofluorescence and flow cytometry. The Kolmogorov-Smirnov test was used for statistical analysis. RESULTS: We found that 17 beta-estradiol augmented the TNF-alpha-induced expression of endothelial leukocyte adhesion molecule-1, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 by 107, 9, and 39%, respectively. Alone, 17 beta-estradiol induced the expression of only intercellular adhesion molecule-1 (24%), as did PGE2 (13%). Neither progesterone nor IL-8 induced expression of any of these adhesion molecules. CONCLUSIONS: Unlike progesterone, 17 beta-estradiol and PGE2 stimulate the expression of adhesion molecules in vitro and may, therefore, promote adhesion of granulocytes to capillary endothelium.

Cells, Cultured↗