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Biomedical subjects

J J Heimans

Publications and source records attributed to J J Heimans.

At least 73 records · Page 4Linked to original sources
PubMed1992

Assessment of quality of life in patients treated for low-grade glioma: a preliminary report.

In this pilot study quality of life was assessed in fourteen adult patients who were treated for a low-grade glioma with surgery and radiotherapy at least one year previously. Apart from widely used parameters, such as the neurological and functional status, the patients' cognitive functioning and actual affective status were determined. In addition the patients were interviewed to evaluate various aspects of quality of life. Generally no serious focal neurological deficits were found, although psychological examination showed serious cognitive and affective disturbances in most cases. Self report measures concerning cognitive functioning were not in all cases in accordance with objective test results. When the results of treatment in glioma patients are evaluated assessment of quality of life, including neuropsychological functioning, should be performed, especially as new therapeutic strategies are being developed.

Activities of Daily Living↗
PubMed1992

Suramin: rapid loading and weekly maintenance regimens for cancer patients.

PURPOSE: Suramin is an anticancer agent with a narrow therapeutic window and a terminal half-life of 45 to 55 days. These characteristics make it necessary to control accurately the serum concentrations of the drug. Therefore, the aim of the present study was to develop a rapid loading regimen, followed by weekly administration of suramin to maintain serum concentrations of between 150 and 300 micrograms/mL for 8 weeks. PATIENTS AND METHODS: Eligible patients were treated with five different loading regimens. Initially, weekly maintenance doses were estimated manually by the treating physician. Subsequently, computer-assisted dosing that used Bayesian pharmacokinetic modeling was used. RESULTS: Thirty-eight courses of suramin that were administered to 35 patients were studied. The optimal loading regimen consisted of a continuous infusion of 600 mg/m2 during a 24-hour period, which resulted in a mean serum concentration of 319 micrograms/mL. Potentially toxic concentrations that were observed with shorter infusions were avoided. Maintenance treatment, which used the weekly administration of suramin during a 6-hour period, seemed to be able to maintain mean suramin serum trough concentrations of 150 micrograms/mL, while preventing mean peak concentrations of more than 300 micrograms/mL. The use of Bayesian pharmacokinetics was superior to manual estimation in tailoring the optimal dose to the therapeutic window. CONCLUSIONS: Continuous infusion is the optimal way of delivering suramin during the loading phase. To maintain trough levels and peak levels within a narrower therapeutic window, suramin will have to be administered more frequently than once a week. Bayesian modeling based on individual serum levels and population pharmacokinetics allows accurate dosing to maintain suramin levels within the therapeutic window.

Adult↗
PubMed1992

Do metastases in vertebrae begin in the body or the pedicles? Imaging study in 45 patients.

We analyzed CT scans of the spine obtained in patients with vertebral metastases to determine what specific portion of the vertebra is initially involved by metastasis. The CT findings were then correlated with the abnormalities seen on plain films. Forty-five patients with histologically proved metastases in 95 vertebrae were included in the study. In all patients, CT scans and plain films of the spine were obtained within 1 week of each other. Analysis of the CT scans showed that the vertebral body was the portion of the vertebra that was most frequently destroyed by the metastases. Destruction of a pedicle was never identified in the absence of involvement of the body. The opposite was true on plain films, in which the most common finding was destruction of the pedicles. CT showed that the position of the metastases in the vertebra correlated with the sites of entry of the vertebral vessels. Our results show that the initial anatomic location of metastases within vertebrae is in the posterior portion of the body. Analysis of CT scans shows that the body is involved before the pedicles, although destruction of the pedicles is the most common finding on plain films. The pedicles are not the primary site of metastatic involvement. Destruction of the pedicles occurs only in combination with involvement of the vertebral body.

Adult↗
PubMed1991

The cause of increased pupillary light reflex latencies in diabetic patients: the relationship between pupillary light reflex and visual evoked potential latencies.

In 42 diabetic patients the relationship between the latency of the pupillary light reflex and the pattern reversal visual evoked potential (P100) was examined. Fifty-five percent of diabetic patients had pupillary light reflex latencies above the normal range. In 19% the visual evoked potentials were prolonged when compared to the normal range. Latencies of pupillary light reflexes and VEPs showed no correlation. There was a minimal correlation between the presence of retinopathy and prolongation of both the pupillary light reflex and the visual evoked response latency (kappa coefficients respectively: 0.31, P less than 0.01 and 0.36, P less than 0.02). The presence of an increased pupillary light reflex latency was positively correlated with a reduced respiratory sinus arrhythmia (kappa coefficient: 0.58, P less than 0.0001). Increased VEP latencies showed no correlation with signs of cardiovascular autonomic neuropathy. We conclude that the afferent optic pathway can be affected in diabetic patients. However, prolongation of pupillary light reflex latency in diabetic patients is primarily due to an efferent pupillary defect and represents parasympathetic dysfunction.

Adult↗
PubMed1991

Cardiovascular autonomic function in multiple sclerosis.

In this study blood pressure (BP) and heart rate (HR) responses to standing and HR responses to deep breathing were assessed in 34 patients with clinically definite multiple sclerosis (MS) and 63 healthy subjects. Normal ranges, which were clearly age related for both HR responses, were obtained. The BP response to standing was abnormal in 13% of the MS patients, these patients demonstrating significant postural hypotension. The HR response to standing was abnormal in 28% of the MS patients, with a normal initial increase in heart rate and a significantly reduced reflex bradycardia. On deep breathing 36% of MS patients showed abnormal HR changes. The resting HR did not differ between both groups. Abnormalities of one or more tests were found in 53% of the MS patients. No relationship was found between abnormal cardiovascular autonomic responses and the symptoms, duration, severity and progression of the disease. Based on clinical and magnetic resonance imaging findings no indications were found for localisation of the autonomic disturbances in the brainstem. It is suggested that at least a part of the cardiovascular autonomic lesions in MS is located outside the brainstem, i.e. in supramedullary reflex pathways or in the spinal cord.

Adult↗
PubMed1991

Treatment of leptomeningeal carcinomatosis with continuous intraventricular infusion of recombinant interleukin-2.

A 42-year-old man developed leptomeningeal carcinomatosis 6 years after treatment of a malignant melanoma. He was treated with two courses of recombinant interleukin-2, administered as a continuous intraventricular infusion (6 X 10E5 U/24 h) during 5 days. During the first day of the first course he also received 5 X 10E9 lymphokine-activated killer cells intraventricularly. This gave rise to a severe elevation of intracranial pressure, with headaches and meningismus. During the second course no LAK cells were administered. This course was tolerated much better. The neurological status did not change during the treatment. Recombinant interleukin-2 levels were maintained at about 300 U/mL during both courses.

Adult↗
PubMed1991

Cold and warm cutaneous sensation in diabetic patients.

The assessment of cutaneous thresholds for thermal sensation is now recognized as a valuable method to detect small nerve fibre function in diabetes. Methods commonly used do not allow separate measurements of warm and cold perception. However, there is evidence that the fibre subtypes which signal cold and warm sensation are different (A-delta-fibres and C-fibres, respectively). To investigate if diabetes affects cold and warm sensation equally, thresholds were assessed separately in 30 diabetic patients (age 47.9 +/- 15.1 (+/- SD) years; duration of diabetes, 19.1 +/- 13.3 years). Comparisons were made with 71 non-diabetic control subjects (age 59.7 +/- 22.1 years). Thermal discrimination thresholds for cold and warm sensation were determined for the left foot with a two-alternative forced choice method. In both diabetic patients and in the control group cooling thresholds were smaller than warming thresholds. In diabetic patients log thermal discrimination thresholds for warmth increased 0.1 per decade (p less than 0.001), a relationship comparable to that seen in non-diabetic patients. There was no relationship between cooling thresholds and age in diabetic patients despite a significant (p less than 0.001) deterioration with age in control subjects. This difference in the influence of age on cold sensitivity was significant (p less than 0.03). Both warm and cold sensation were not related to the duration of diabetes. We conclude that assessment of warm threshold is preferred for the detection of minor disturbances of small nerve fibre function in diabetes.

Adult↗
PubMed1991

Cyclandelate in diabetic neuropathy. A double-blind, placebo-controlled, randomized, cross-over study.

Cyclandelate has the ability to improve the rheological properties of the blood and therefore may improve blood supply of peripheral nerves. Previous studies in diabetic neuropathy have shown beneficial effects of the drug. We performed a double-blind, placebo-controlled, cross-over study in 40 diabetic patients with cyclandelate in a dose of 1600 mg daily. Motor and sensory nerve conduction velocities, late responses, thermal discrimination thresholds, vibration perception thresholds and pain scores were studied. We were not able to show any positive effect of the drug and therefore conclude that cyclandelate is not effective in the treatment of diabetic neuropathy.

Adult↗
PubMed1990

Prevention of cisplatin neurotoxicity with an ACTH(4-9) analogue in patients with ovarian cancer.

In a randomized, double-blind, placebo-controlled study, we assessed the efficacy of an ACTH(4-9) analogue, Org 2766, in the prevention of cisplatin neuropathy in 55 women with ovarian cancer. The analogue was given subcutaneously in a dose of 0.25 mg (low dose) or 1 mg (high dose) per square meter of body-surface area before and after treatment with cisplatin and cyclophosphamide (75 and 750 mg per square meter every three weeks). The threshold of vibration perception was used as the principal measure of neurotoxicity. After four cycles of chemotherapy, the mean (+/- SEM) threshold value for vibration perception in the placebo group increased from 0.67 +/- 0.12 to 1.61 +/- 0.43 microns of skin displacement (P less than 0.0001). In the high-dose treatment group, there was no increase in the threshold value after four cycles (from 0.54 +/- 0.12 to 0.50 +/- 0.06 micron). After six cycles of chemotherapy, the threshold value was 5.87 +/- 1.97 microns in the placebo group (more than an eight-fold increase from base line), as compared with 0.88 +/- 0.17 micron (less than a twofold increase) in the high-dose treatment group (P less than 0.005). In the high-dose group, fewer neurologic signs and symptoms were recorded than in the placebo group. With the lower dose of the analogue, these protective effects were less prominent. No side effects were seen after treatment with Org 2766. The rates of clinical response to chemotherapy were similar in all groups. These results suggest that Org 2766 can prevent or attenuate cisplatin neuropathy without adversely affecting the cytotoxic effect of the drug.

Adrenocorticotropic Hormone↗
PubMed1990

Accuracy and interobserver variation in the interpretation of computed tomography in solitary brain lesions.

The clinical data and computed tomographic findings of 64 patients with solitary supratentorial brain lesions were presented to two panels of six experienced clinicians. The diagnoses predicted by these clinicians were compared with each other (interobserver variation) and with the definite diagnosis, which in almost all cases was based on histologic examination of the involved tissue (validity of predicted diagnosis). The interobserver agreement was only moderate. The predicted diagnoses agreed with the definite diagnoses in only 57% of cases. A high number of errors were made in distinguishing between high-grade and low-grade glioma and between high-grade glioma and cerebral metastasis, and in the detection of primary cerebral lymphoma. Possible implications of these findings for clinical practice are discussed.

Adult↗
PubMed1990

Longterm meningeal involvement as the only clinical manifestation of low grade malignant non-Hodgkin's lymphoma.

We present the case of a 56-year-old man who developed-at the age of 46-paraesthesia and numbness in the perianal region, the feet and lower legs accompanied by the presence of B-lymphocytes in the cerebrospinal fluid (CSF). Despite intensive work-up an explanation was not found until he developed hepato-splenomegaly ten years after the initial symptoms. Haematologic evaluation at that time disclosed a low-grade malignant B-cell lymphoma. Repeated CSF examination revealed 31 leukocytes/mm3, of which were mainly lymphocytes. These proved to be B-lymphocytes of monoclonal origin. These findings suggest that a leptomeningeal localisation of a low-grade malignant lymphoma had been present for ten years before systemic manifestation of the disease.

Adult↗
PubMed1990

Assessment of pupillary light reflex latency and darkness adapted pupil size in control subjects and in diabetic patients with and without cardiovascular autonomic neuropathy.

Increased pupillary light reflex latencies were found more often than a reduced darkness pupil size in diabetic patients with and without abnormal cardiovascular reflexes. This finding suggests that parasympathetic pupillary dysfunction precedes sympathetic pupillary denervation in diabetic autonomic neuropathy.

Adolescent↗
PubMed1989

The relationship of cold and warmth cutaneous sensation to age and gender.

To evaluate cold and warmth cutaneous sensation separately, thermal discrimination thresholds (TDTs) for the foot were estimated for cold and warm stimuli in 71 normal subjects aged between 21 and 92 years. A "thermoaesthesiometer" operating on the Peltier principle was used. A rise of TDTs with age was found. Furthermore, female subjects appeared to have lower thresholds than males. Independent of age or gender, TDTs for cold stimuli were on average lower than for warm stimuli. In accordance with other studies, a large intraindividual variability was found, which emphasizes the necessity for repeated measurements.

Adult↗
PubMed1989

Imaging of brain metastases. Comparison of computerized tomography (CT) and magnetic resonance imaging (MRI).

For the demonstration of brain metastases both CT and MRI are available as diagnostic modalities. To compare both imaging methods as to their sensitivity in detecting brain metastases CT scans and MR images of 60 patients with suspected brain metastases were evaluated. Comparing contrast-enhanced CT and plain MRI neither modality was found to be clearly superior in this respect.

Adolescent↗
PubMed1989

Peripheral nerve function in children with end-stage renal failure.

Information on clinical and subclinical peripheral neuropathy in children with end-stage renal failure (ESRF) is scarce. We have studied the presence of clinical and subclinical peripheral neuropathy in children with ESRF comparing recently developed non-invasive methods with the measurement of nerve conduction velocities. Twelve children (7 boys, 5 girls; age range: 5-17 years; duration of haemodialysis: 0.5-60 months) participated. Thermal discrimination threshold (TDT) and vibration perception threshold (VPT) were determined twice before and after haemodialysis in each patient. Peroneal nerve conduction velocity was determined once before haemodialysis. No clinical or subclinical peripheral neuropathy was observed in any of the children. Except for two slightly increased TDT values after haemodialysis all results were within the normal range. No correlation was found with age or duration of haemodialysis and no association was found between the three methods. VPT values showed a significant improvement after haemodialysis treatment, although all VPT values were in the normal range. This suggests that haemodialysis has an influence on cutaneous sensation, but further study is needed to confirm this observation. Longitudinal investigations will be necessary to evaluate whether TDT and VPT determinations can be used for early screening of clinical and subclinical neuropathy in children with ESRF.

Blood Chemical Analysis↗
PubMed1989

Alpha 2-adrenoceptor-mediated modulation of noradrenaline release is decreased in vas deferens but not in cerebral cortex of diabetic rats.

In the present study, a superfusion method was used to investigate the alpha 2-adrenoceptor mediated modulation of the electrically evoked release of radiolabeled noradrenaline in vas deferens and cerebral cortex slices of streptozotocin-diabetic and control rats 8-10 weeks after the induction of diabetes. Stimulation of alpha 2-adrenoceptors led to a significantly smaller inhibition of radiolabeled noradrenaline release in the vas deferens of diabetic rats as compared to control rats. In the cerebral cortex no such difference was detected. It is concluded that these effects could be due to a decrease in the number of presynaptic alpha 2-adrenoceptors in the vas deferens of diabetic rats. The results of this study show that the superfusion technique offers a simple possibility to obtain information about the functional integrity of noradrenergic neurons in the peripheral nervous system and central nervous system in diabetes mellitus. Moreover, the results provide an indication for a different time scale in the development of neuropathy in the peripheral and central nervous system of streptozotocin-diabetic rats.

Animals↗
PubMed1989

Autonomic and somatic peripheral nerve function and the correlation with neuropathic pain in diabetic patients.

Pupillary and cardiovascular autonomic functions were examined in 25 diabetic patients with and 25 diabetic patients without painful neuropathy. There were no significant differences between the groups with regard to age, duration of diabetes or glycaemic control. Vibratory perception, reflecting peripheral large fibre function, was more severely disturbed in the symptomatic group (P = 0.003). Thermal discrimination thresholds (TDTs), reflecting somatic small fibre function, were abnormal in all symptomatic patients and the difference between patients with and without symptoms was more pronounced (P less than 0.0001), than for large fibre function. The latency of the constriction reaction of the pupil (parasympathetic function) was prolonged in 17 symptomatic patients and in 6 patients without pain; it proved to be significantly more prolonged in the group with painful neuropathy (P = 0.001). Cardiovascular autonomic neuropathy was present in 29 patients, especially in patients with painful neuropathy (22 in the group with painful neuropathy, 7 in the group without pain). There was a significant correlation between results of TDT and respectively pupillary and cardiovascular autonomic function tests (kappa coeëfficient: 0.63 and 0.56, respectively, P less than 0.0001). We conclude that autonomic dysfunction is often present in patients with painful neuropathy. However, thermal sensory dysfunction is better correlated with the presence of symptoms than cardiovascular and pupillary autonomic dysfunction.

Adult↗