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Biomedical subjects

M de Vries

Publications and source records attributed to M de Vries.

At least 19 recordsLinked to original sources
PubMed2005

[Sentinel lymph node biopsy for melanoma: prognostic value and disadvantages in 300 patients].

OBJECTIVE: The aim of this study was to evaluate the advantages and disadvantages of sentinel lymph node biopsy (SLNB) in patients with cutaneous melanoma. DESIGN: Descriptive follow-up study. METHOD: In the period 1995-2004, 300 patients with cutaneous melanoma (Breslow thickness: > or = 1.0 mm) underwent SLNB and, in case of a tumour-positive result, regional lymph node dissection. Results of the SLNB procedure, postoperative complications, follow-up, recurrences, disease-free survival and disease-specific survival were evaluated. RESULTS: The SLNB detection rate was 99%. 85 patients had a tumour-positive SLNB (28%) and underwent completion regional lymph node dissection; 215 patients underwent SLNB alone. The rate of postoperative complications after SLNB was 7%. With a median follow up of 51 months, the false-negative rate was 11%. The recurrence rate was 23% (SLNB negative: 19%; SLNB positive 34%; p = 0.005). In-transit metastases were found in 4% of the SLNB-negative group and in 20% of the SLNB-positive group (p < 0.001). The 5-year disease-free survival and disease-specific survival rates were 79% and 86%, respectively, in SLNB-negative patients and 57% and 71%, respectively, in SLNB-positive patients. Multivariate analysis showed that the independent prognostic factors for disease-free survival were presence of ulceration (p < 0.001) and SLNB positivity (p < 0.01). Prognostic factors for overall survival were presence of ulceration (p < 0.001) and male sex (p < 0.05), but not the SLNB results. Multivariate analysis also showed that SLNB positivity (p < 0.001) and presence of ulceration (p < 0.01) were independent prognostic factors for developing in-transit metastases. CONCLUSION: SLNB in patients with cutaneous melanoma is still only of prognostic value since survival benefit is not proven. Disadvantages of SLNB were the false-negative rate, the possibility of an increased risk of in-transit metastases in SLNB-positive patients, and postoperative complications. These must be kept in mind when offering patients SLNB.

Adolescent↗
PubMed2005

The intake of total protein, natural protein and protein substitute and growth of height and head circumference in Dutch infants with phenylketonuria.

In a previous study, Dutch children with phenylketonuria (PKU) were found to be slightly shorter than their healthy counterparts. In the literature, it has been hypothesized that a higher protein intake is necessary to optimize growth in PKU patients. The study aimed to investigate whether protein intake (total, natural and protein substitute) in this group might be an explanatory factor for the observed growth. Growth of height and head circumference and dietary data on protein intake (total, natural and protein substitute) from 174 Dutch PKU patients born between 1974 and 1996 were analysed retrospectively for the patients' first 3 years of life. Analyses were corrected for energy intake during the first year of life and for the clinical severity of the deficiency of phenylalanine hydroxylase by means of plasma phenylalanine concentration at birth. Neither protein nor energy intake correlated with height growth. A positive, statistically significant relation between head circumference growth and natural protein and total protein intake was found, but not with the intake of the protein substitute or energy. Therefore, this study suggests that improvement of the protein substitute rather than an increase of total protein intake may be important in optimizing head circumference growth in PKU patients.

Body Height↗
PubMed2005

Morbidity after axillary sentinel lymph node biopsy in patients with cutaneous melanoma.

AIM: In this study, the short-term and long-term morbidity was assesed after axillary sentinel lymph node biopsy (SLNB) with or without completion axillary lymph node dissection (SLNB/ALND) in patients with cutaneous melanoma. METHODS: Between 1995 and 2003, 119 axillary SLNBs were performed for cutaneous melanoma. Fifty-eight patients met the inclusion criteria and entered the study. RESULTS: Forty-four patients underwent SLNB alone and 14 patients underwent axillary lymph node dissection after positive SLNB. Complications after SLNB alone: post-operative bleeding (n=2), seroma (n=1) and slight lymphedema 11%. Complications after SLNB/ALND: wound infections (n=2), seroma (n=5) and slight lymphedema 7%. There were differences between the two groups in short-term complications (p<.001) and functional limitations of the shoulder (p=.011). CONCLUSION: Axillary SLNB alone had a low complication rate. However, SLNB followed by completion ALND was associated with an increased risk of short- and long-term complications.

Adult↗
PubMed2002

Sleep problems and daytime problem behaviours in children with intellectual disability.

BACKGROUND: Sleep problems are common among children with intellectual disability (ID). METHOD: The present study assessed the prevalence of severe sleep problems in a sample of children (n=286) with mild to profound ID who lived at home with their parents(s) in the Netherlands. It also explored relationships between severe sleep problems, and family and child variables. Demographic information, data on children's sleep behaviours and parent variables were collected using questionnaires. RESULTS: Severe settling problems, night waking and early waking were present in 4.2%, 10.8% and 4.2% of cases, respectively; 16.1% of children had at least one type of sleep problem. Children with a severe sleep problem had more severe levels of ID, used medication more often, had a greater frequency of epilepsy, were younger, had a greater frequency of cerebral palsy, and showed more daytime drowsiness and daytime napping than children without a severe sleep problem. Furthermore, children with a severe sleep problem showed more severe levels of daytime problem behaviours; for example, aggression, non-compliance and hyperactivity. CONCLUSION: The results of the present study are discussed with regard to the assessment and treatment of sleep problems in children with ID.

Adolescent↗
PubMed2002

Physical activity and exercise performance in symptomatic Cambodia veterans.

BACKGROUND: Dutch (ex-)servicemen who encounter health problems since return from the 1992-3 peace operation UNTAC, commonly complain of reduced activity levels, decreases in physical fitness and aggravation of symptoms after strenuous exercise. AIM: To evaluate these symptoms. DESIGN: A prospective study of 26 symptomatic Cambodia veterans and 26 matched controls (healthy Cambodia veterans). METHODS: Using an actometer and diaries, both groups were followed for a 12-day baseline period prior to an incremental maximal exercise test on a bicycle ergometer, followed by 7 days of post-ergometer data. RESULTS: During baseline, symptomatic Cambodia veterans reported more symptoms, had lower levels of physical activity and took longer periods of rest after high activity periods. Symptomatic veterans did not perceive the exercise test needing more exertion than healthy veterans did, although their physical fitness was decreased. Post-ergometer, daily observed symptoms did not aggravate in symptomatic veterans. Four days post-ergometer, actometer and daily observed activity scores were lowered in both groups. As compared to baseline, one day post-ergometer, levels of physical activity were changed in healthy veterans, but not in controls. DISCUSSION: Complaints about reduced activity levels and decreases in physical fitness in symptomatic Cambodia veterans were confirmed. Post-exertion malaise was not found. The observed post-exertion effects were traced back to weekday patterns.

Adult↗
PubMed2002

A pharmacokinetic comparison of the modified release capsule and a plain tablet formulation of mebeverine.

This study was conducted to compare the pharmacokinetic properties of the modified release 200 mg capsule of mebeverine and the plain 135 mg tablet of mebeverine after single and multiple doses in 12 healthy subjects in a randomised, crossover design. Single doses were given on days 1 and 7 and multiple doses (200 mg b.i.d. for the capsule and 135 mg t.i.d. for the tablet) on days 2-6 of the study. The 200 mg modified release capsule of mebeverine has extended release properties, as indicated by a lower Cmax, a later tmax and a longer elimination half-life than the plain tablet, while the bioavailability is optimal. No significant accumulation occurs after multiple doses of either formulation. The twice-daily dosage regimen of the 200 mg modified release capsule is a good alternative to the three times daily dosage regimen of the 135 mg plain tablet, because the reduced daily intake is likely to benefit patient compliance.

Adult↗
PubMed2001

Matrix-assisted laser desorption/ionization quadrupole time-of-flight mass spectrometry: an elegant tool for peptidomics.

A Matrix-assisted laser desorption/ionization hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer was employed to acquire neuropeptide mass spectra, directly from neuropeptide secreting tissue deposited on the sample target, in the presence of dihydroxybenzoic acid as matrix. The cockroach corpus cardiacum served as model neuroendocrine tissue. Twelve neuropeptide ion peaks, with mass-to-charge ratio values ranging between 800 and 3,000 Da were selected for tandem mass spectrometry. All peptides below 1,600 Da could be fully sequenced; tandem mass spectrometry analysis of the remaining (three) largest peptides resulted in (limited) sequence tags, which, also due to unavailability of an appropriate neuropeptide structure database, did not allow complete structure elucidation.

Amino Acid Sequence↗
PubMed2000

Measurement of prolonged fatigue in the working population: determination of a cutoff point for the checklist individual strength.

In the Netherlands, a large-scale prospective cohort study was started on prolonged fatigue in the working population. The 1st issue that had to be addressed was the determination of a cutoff point for fatigue for use in the working population. Fatigue is measured with the Checklist Individual Strength (CIS), a 20-item self-report questionnaire. This article demonstrates the process of decision making in the determination of the cutoff point. Total CIS scores were calculated, sensitivity and specificity were compared for potential cutoff points, and a receiver operating characteristics analysis was conducted. A CIS total cutoff point for fatigue of >76 was determined, with a specificity of 90% and a sensitivity of 73%. Limitations regarding the use of cutoff points are discussed. It is concluded that the defined cutoff point seems to be appropriate for use in the working population.

Adult↗
PubMed2000

Somatic hypotheses of war syndromes.

Since the end of the American Civil War, unexplained symptoms in military personnel arising after a war or peace mission have frequently been described. The pattern of symptoms is highly similar for all of the various war syndromes although the conditions of each war or peace mission are widely different. Many somatic hypotheses have been formulated to explain these syndromes; a considerable proportion of them are already outdated. In the last few years much attention has been given to Gulf War Syndrome and to unexplained symptoms of military personnel who were sent to Cambodia, Rwanda, Burundi, Zaire, or the former Yugoslavia. In this review the symptoms of war syndromes will be considered in more detail and the suggested somatic explanations will be discussed. During the last decade the following somatic causes have been suggested as possible explanations for these symptoms: (persistent) infection, abnormal immune response, administration of multiple vaccinations within a short period of time, use of malaria chemoprophylaxis, neurological abnormalities, exposure to toxicological substances and environmental factors. The various investigations performed to study these hypotheses are discussed. The fact that bias regularly occurs in the course of these investigations is pointed out. For the future, a reliable investigation of a war syndrome should be a prospective multidisciplinary study and should distinguish between causative and sustaining factors.

Combat Disorders↗
PubMed2000

Fatigue in Cambodia veterans.

In 1992 and 1993, Dutch military personnel were deployed in the peace operation UNTAC in Cambodia. Since returning, Cambodia veterans have reported health complaints which they perceive to be related to their service. Their symptoms strikingly resemble health problems reported by Gulf War veterans. Four years post-return, a cross-sectional survey on health symptoms in Cambodia veterans was initiated. Questionnaires were sent to all Cambodia veterans and four comparison groups. Forgetfulness, difficulty concentrating and fatigue were the symptoms most commonly endorsed. An operational case definition was constructed using a validated fatigue severity questionnaire. Cases were not uniquely found in Cambodia veterans (17%). In Rwanda and Bosnia veterans, respectively, 28% and 11% also met our case definition. Fatigue severity level was predicted by pre-mission, during-mission and post-mission variables, of which retrospective recollection of side-effects of vaccines and causal attributions also have been shown to be relevant in studies on Gulf-related illness.

Adult↗
PubMed1999

[Somatic and psychological symptoms in soldiers after military clashes and peace-keeping missions].

Dutch soldiers who have participated in the peace keeping operation United Nations Transitional Authority in Cambodia (UNTAC) have reported various somatic and psychological symptoms since their return. Their symptoms show similarities to the Gulf War Syndrome. The question arises whether Gulf War Syndrome, symptoms in UNTAC soldiers and other symptoms after acts of war and peace operations are unique syndromes or comparable complaints? From an historical overview it is not plausible that new and unique syndromes will occur with each war or peace operation. On the other hand it also seems unlikely that war syndromes can be reduced to one diagnostic category. The post-Cambodia complaints may be described in four hypothetical models: the somatic start model, the psychotrauma start model, the premorbidity model and the complaints-not-related-to-Cambodia model. These models are expected to be applicable, after further validation, to other symptoms after acts of war and peace operations. Also they will provide points of application for prevention and treatment of symptoms after future wars and peace operations.

Adult↗
PubMed1999

Postoperative treatment of glioblastoma with BNCT at the petten irradiation facility (EORTC protocol 11,961).

The boron neutron capture therapy is based on the reaction occurring between the isotope 10B and thermal neutrons. A low energy neutron is captured by the nucleus and it disintegrates into two densely ionising particles, Li nucleus and He nucleus (alpha particle), with high biological effectiveness. On the basis of comprehensive preclinical investigations in the frame of the European Collaboration with Na2B12H11SH (BSH), as boron delivery agent, the first European phase I, clinical trial was designed at the only available epithermal beam in Europe, at the High Flux Reactor, Petten, in the Netherlands. The goal of this study is to establish the safe BNCT dose for cranial tumors under defined conditions. BNCT is applied as postoperative radiotherapy in 4 fractions, after removal of the tumor for a group of patients suffering from glioblastoma, who would have no benefit from conventional treatment, but have sufficient life expectancy to detect late radiation morbidity due to BNCT. The starting dose is set at 80% of the dose where neurological effects occurred in preclinical large animal experiments following a single fraction. The radiation dose will be escalated, by constant boron concentration in blood, in 4 steps for cohorts of ten patients, after an observation period of at least 6 months after the end of BNCT of the last patient of a cohort. The adverse events on healthy tissues due to BSH and due to the radiotherapy will be analysed in order to establish the maximal tolerated dose and dose limiting toxicity. Besides of the primary aim of this study the survival will be recorded. The first patient was treated in October 1997, and further four patients have been irradiated to-date. The protocol design proved to be well applicable, establishing the basis for scientific evaluation, for performance of safe patient treatment in a very complex situation and for opening the possibility to perform further clinical research work on BNCT.

Brain Neoplasms↗
PubMed1999

Relationship of estradiol levels to breakthrough bleeding during continuous combined hormone replacement therapy.

OBJECTIVE: To determine whether serum estradiol and dydrogesterone concentrations are associated with the occurrence of breakthrough bleeding. METHODS: In a prospective, double-blind study, 194 postmenopausal women were allocated randomly to receive one of four doses of dydrogesterone (2.5 mg, 5 mg, 10 mg, 15 mg) continuously combined with 2 mg of micronized 17beta-estradiol. All medication was taken orally for a total of 168 days. Vaginal bleeding was recorded on a daily basis. Serum estradiol (E2) and dihydrodydrogesterone (the main metabolite of dydrogesterone) trough levels were measured at day 85 and at the end of the study (day 168). Bleeding pattern analysis was done according to the reference period method. RESULTS: One hundred fifty-two of 177 women who completed the study supplied valid data on drug compliance, smoking habits, bleeding episodes, and serum hormone concentrations, which were used to assess the impact of serum E2 and dihydrodydrogesterone concentrations on the occurrence of breakthrough bleeding. Logistic regression analysis identified only the serum E2 concentration as having an independent, statistically significant effect (P = .003) on the occurrence of breakthrough bleeding; no such effect was associated with dihydrodydrogesterone levels (P = .118). The relative risk for the occurrence of breakthrough bleeding was 2.7 (95% confidence interval [CI] 1.454, 5.609) for serum E2 concentrations greater than 40 pg/mL. CONCLUSION: The occurrence of breakthrough bleeding during continuous combined hormone replacement therapy with estradiol and dydrogesterone in postmenopausal women was related to serum estradiol levels and not to dydrogesterone levels. Further studies are needed to test the hypothesis that estrogen is a major factor in the incidence of bleeding during postmenopausal hormone replacement therapy.

Adult↗
PubMed1997

TNF-alpha has no direct in vivo metabolic effect on human muscle.

Tumor necrosis factor alpha (TNF-alpha) is thought to have a key role in metabolic changes of muscle tissue during inflammatory diseases. It is unknown whether TNF-alpha affects muscle metabolism directly or whether these changes are mediated by secondary mediators. We studied 6 patients undergoing isolated limb perfusion with TNF-alpha for irresectable soft-tissue sarcoma or in-transit melanomas. Glucose, lactate, ammonia and amino-acid consumption or production were measured in the perfusate during 3 perfusion periods: before, after TNF-alpha and after the combined administration of TNF alpha and melphalan. Arterial glucose, lactate, ammonia and amino-acid concentrations were monitored to detect metabolic effects of TNF-alpha after it entered the systemic circulation. Glucose uptake and lactate release by the limb remained unchanged after the injection of TNF-alpha alone, as well as after the combination of TNF-alpha and melphalan. Furthermore, glutamine, alanine, phenylalanine, tyrosine and total amino-acid release into the perfusate did not increase during TNF-alpha and melphalan treatment, indicating that muscle metabolism was not changed. After the isolated limb perfusion, TNF-alpha entered the systemic circulation and induced metabolic changes resulting in a doubling of arterial lactate concentrations, decreased arterial glucose concentrations and decreased arterial amino-acid concentrations. Our study shows that regional administration of TNF-alpha alone or in combination with melphalan does not directly affect muscle glucose and protein metabolism. The data suggest that systemic metabolic changes induced by TNF-alpha are mediated through secondary, centrally produced, factors.

Adolescent↗