Biomedical subjects

J van der Zee

Publications and source records attributed to J van der Zee.

At least 91 records · Page 5Linked to original sources

PubMed1985

Peroxide-induced membrane damage in human erythrocytes.

Erythrocytes exposed to H2O2 or t-butyl hydroperoxide (tBHP) exhibited lipid peroxidation and increased passive cation permeability. In the case of tBHP a virtually complete inhibition of both processes was caused by butylated hydroxytoluene (BHT), whereas pretreatment of the cells with CO increased both lipid peroxidation and K+ leakage. In the experiments with H2O2, on the other hand, both BHT and CO strongly inhibited lipid peroxidation, without affecting the increased passive cation permeability. These observations indicate different mechanisms of oxidative damage, induced by H2O2 and tBHP, respectively. The SH-reagent diamide strongly inhibited H2O2-induced K+ leakage, indicating the involvement of SH oxidation in this process. With tBHP, on the contrary, K+ leakage was not significantly influenced by diamide. Thiourea inhibited tBHP-induced K+ leakage, without affecting lipid peroxidation. Together with other experimental evidence this contradicts a rigorous interdependence of tBHP-induced lipid peroxidation and K+ leakage.

Butylated Hydroxytoluene↗

PubMed1985

Human tumour pH and its variation.

The variation in human tumour pH values is large. The aim of this study was to analyse the reasons for these large variations and to determine whether tumour pH can be predicted on the basis of any easily measured parameter. One hundred and five determinations of tumour pH were performed in various human tumours, using the Philips C 902S tissue pH electrode. No correlations were found between the tumour pH and the tumour histology, degree of differentiation, tumour size, patient age or treatment history, and whether or not the tumour was ulcerated. However, tumour pH was significantly lower in primary tumours than in lymph node metastases. Tumours at their primary site (primary, recurrent or residual) were also more acid than distant metastases. The vascular disruption caused by the measuring technique was found to be acceptable.

Animals↗

PubMed1985

Two human IgM myeloma proteins with unusual specificities for streptococcal carbohydrate-associated epitopes.

Five hundred and fifty human sera from patients with IgM myeloma or Waldenström's macroglobulinaemia were screened by a solid-phase enzyme-linked immunoassay for binding to the carbohydrate of group A streptococci (A-CHO). Two of them (AC8 and AC179) contained immunoglobulin, which bound specifically to A-CHO even at serum dilutions of 1:10(7). Using synthetic oligosaccharides coupled to protein for inhibition studies, the fine specificities of AC8 and AC179 were determined. AC179 is directed to alpha-linked rhamnose oligosaccharides. AC8 appears to be specific for N-acetyl-D-glucosamine (GlcNAc) side chains beta(1----2)-linked to rhamnose, whereas GlcNAc side chains in A-CHO are reported to be beta(1----3)-linked to the rhamnose backbone. Naturally occurring anti-A-CHO antibodies consist mainly of low-affinity antibodies to such beta(1----3)-linked GlcNAc. In contrast, both myeloma antibodies show more than 10 times higher relative affinities to A-CHO than antibodies prepared from normal human serum (anti-GlcNAc and anti-A-CHO, respectively) by selection for high affinity in the elution procedure. AC179 induced complement activation in the presence of A-CHO.

Acetylglucosamine↗

PubMed1985

Clinically derived dose effect relationship for hyperthermia given in combination with low dose radiotherapy.

A group of 36 patients, treated on 44 fields with fractionated treatments of local high-frequency induced hyperthermia and radiotherapy to the low total dose of 14-25 Gy, was retrospectively evaluated for differences between responders (i.e., complete and partial responders) and non-responders. A response rate of 86% was achieved, comprising 14% (6/44) complete and 73% (32/44) partial response. There was an indication that the probability of complete response is greater in smaller tumours. The tumour temperatures achieved were higher in the responders than in the non-responders. Logistic analysis was performed on the mean temperature achieved. This temperature parameter yielded a significant positive dose-effect relationship with regard to therapeutic effect, from which a 50% effective dose of 38.8 degrees C was calculated. The data indicate that to obtain the maximum therapeutic effect, i.e., greater than 95% response rate, tumour temperatures above 42.5 degrees C need to be achieved.

Adult↗

PubMed1984

The importance of monopole-monopole and monopole-dipole interactions on the binding of NADPH and NADPH analogues to p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens. Effects of pH and ionic strength.

NADPH binding to p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens is found to be strongly dependent on pH and ionic strength. In the ionic strength range of 0.02-0.15 M, optimal NADPH binding is observed at a pH value of 6.4. Extrapolation of the dissociation constants to infinite ionic strength shows that under these conditions optimal binding occurs at pH values greater than 8. Similar results were obtained for complexes between the enzyme and two NADPH analogues in the presence or absence of the substrate. The experimental data can be explained by a theoretical model in which monopole-monopole or monopole-dipole interactions between the enzyme and the ligand are dominant. Changes in the former interaction prevail at low ionic strength and low pH values while the changes in the latter prevail at high ionic strength and high pH values. The dipole moment of the enzyme in the direction of the NADPH binding site was calculated from the ionic strength and pH dependence of the complex formation. The calculated dipole moment of the enzyme is about 2000 Debye at pH 6 and decreases to about 1100 Debye at pH 8.5. The results are discussed with respect to published results, including data obtained from the enzyme from a different source.

4-Hydroxybenzoate-3-Monooxygenase↗

PubMed1984

Cardiovascular changes during whole body hyperthermia treatment of advanced malignancy.

Cardiovascular studies were carried out on patients subjected to whole body hyperthermia treatment for advanced malignancy in order to assess the magnitude of the changes occurring and the degree of strain imposed on the system. The subjects, who were anaesthetised with a nitrous oxide/oxygen and relaxant sequence, were heated in a modified Siemens hyperthermia cabin and maintained at a body temperature of 41.8 degrees C for 2 h. The results of 30 treatments are presented. Large increases in cardiac output and heart rate were accompanied by large decreases in peripheral resistance in both the systemic and pulmonary vascular beds. The pulmonary arterial pressure rose whereas that in the systemic circulation fell. This caused right ventricular work to increase proportionately more than left ventricular work. Care should be exercised when subjecting patients with limited right ventricular function to this treatment.

Cardiac Output↗

PubMed1983

Cerebral temperature and epidural pressure during whole body hyperthermia in dogs.

Whole body hyperthermia was performed on 13 anaesthetized and intubated dogs. Cerebral temperature and epidural pressure were measured and related to rectal and oesophageal temperatures. The brain temperature was significantly higher than that of the rectum at normotemperature. The temperature gradients lessened during heating. At maximum rectal temperature (plateau) small differences between the left and right hand sides of the brain were seen, the temperatures being 0.4 degrees C and 0.3 degrees C higher than the rectal temperature, respectively. During the 2-h plateau period the difference between brain and oesophageal temperature became progressively smaller. The mean epidural pressure decreased slightly during the course of the treatment, but remained within the normal range of 1.2 +/- 0.4 KPa (8.7 +/- 2.5 mm Hg). From this investigation may be concluded that (1) the cerebral temperature is reflected better by the oesophageal than by the rectal temperature and (2) the epidural pressure does not increase during whole body hyperthermia for 2 h at a rectal temperature of up to 42.5 degrees C.

Animals↗

PubMed1983

Whole-body hyperthermia in cancer therapy: a report of a phase I-II study.

Twenty-seven patients were treated with whole-body hyperthermia alone or in combination with either chemotherapy or radiotherapy. Whole-body hyperthermia was performed in the Pomp-Siemens cabin with hot air and a warm water mattress, the patient being covered with plastic film to avoid cooling by perspiration. The heat treatment lasted for 2 hr at 41.8-42.0 degrees C. Toxicity, such as liver damage and respiratory problems, was considerable. There were two fatalities. Hyperthermia gave an improved therapeutic effect in 6 of the patients. Considerable pain relief was observed in 8 of 10 patients. Whole-body hyperthermia at 42 degrees C can be effective but the potential toxicity limits its use to those patients with severe complaints for whom no other palliative treatment is available.

Adult↗

PubMed1982

Tumour pH in human mammary carcinoma.

Human tumour pH was investigated using the new Philips C902S tissue pH electrode. In 22 mammary carcinomas a pH of 7.29 +/- 0.050 (S.E.M.) was observed, whereas in the human subcutis this value was 7.63 +/- 0.034. Tumour pH in some experimental rat tumours was slightly lower than in humans, 7.15 +/- 0.029 in rhabdomyosarcoma BA1112 and 7.07 +/- 0.024 in a small group of other miscellaneous rat tumours. Rat skeletal muscle was found to have a pH of 7.59 +/- 0.070. It is concluded that a small but highly significant (P less than 0.0001) pH difference exists between human mammary carcinoma and human subcutis. This difference is smaller than expected on the basis of animal studies.

Animals↗

PubMed1982

Use of the Pomp-Siemens hyperthermia cabin.

The Pomp-Siemens hyperthermia cabin has been in use in seven European units since 1966. Almost 2,000 treatments with a large variety of intensities have been performed on 332 patients. The cabin, with its combination of radiofrequency, hot air, and microwave energy has provided a flexible and reliable way of treating patients with hyperthermia.

Hot Temperature↗

PubMedDate not supplied

Point-counterpoint: what is the optimal trial design to test hyperthermia for carcinoma of the cervix? Point: addition of hyperthermia or cisplatin to radiotherapy for patients with cervical cancer; two promising combinations--no definite conclusions.

Randomized trials have shown that results of radiotherapy in patients with cervical cancer can be improved by combining the treatment with either cisplatin based chemotherapy, or hyperthermia. The studies on both the combination of radiotherapy with chemotherapy, and the combination on radiotherapy with hyperthermia, leave several important questions unanswered. At present, no definite conclusions can be drawn with regard to which combination results in the best therapeutic ratio. Therefore, on both ethical and scientific grounds, the next logical step would be to compare the two types of combined treatment to each other, and each combination with a treatment including all three modalities, in a randomized fashion.

Antineoplastic Agents↗

PubMedDate not supplied

The Dutch Deep Hyperthermia Trial: results in cervical cancer.

BACKGROUND: Radiotherapy plus hyperthermia was compared to radiotherapy alone in the Dutch Deep Hyperthermia Trial, in patients with advanced bladder, cervical, and rectal tumours. The overall results, published elsewhere, demonstrate that addition of hyperthermia to radiotherapy improves both pelvic control and overall survival rates. The therapeutic gain appeared especially worthwhile in locally advanced cervical tumours. Here, the results in patients with cervical cancer are summarized and discussed, and further details provided. METHODS: From 1990-1996, 114 patients with cervical cancer were entered into this prospective randomized trial. RT was applied to a median total dose of 68 Gy. HT was given once weekly. The median follow-up time was 43 months. All randomized patients were included in the statistical analysis, which was done by intention to treat. The primary end points of the trial were complete response (CR) and duration of pelvic control (PC), secondary end points were overall survival (OS) and toxicity. Besides, an economic evaluation was performed. RESULTS: CR rates were 57% following RT and 83% following RT + HT(p = 0.003). The difference in PC was maintained during follow-up, with 3-year LC rates of 41% following RT and 61% following RT + HT. The 3-year OS rates were 27% and 51% following RT and RT + HT, respectively (p = 0.009). When the patients were divided into two subgroups by whether or not the planned RT was completed, a beneficial effect of hyperthermia was observed in both subgroups. Radiation toxicity was not enhanced by HT. Additional hyperthermia proved to be cost-effective, with maximum discounted cost-per-life-year gained of about Euro 4000. CONCLUSION: Hyperthermia in addition to standard radiotherapy of locally advanced cervical tumours results in therapeutic gain and is cost-effective.

Adult↗

PubMedDate not supplied

The use of implanted closed-tip catheters for the introduction of thermometry probes during local hyperthermia treatment series.

In the past two and a half years custom-made closed-tip catheters have been used to allow extensive temperature monitoring with multi-junction thermocouple probes during local hyperthermia. Data from animal experiments indicate that the use of thermometry probes within such a catheter provides reliable temperature measurements. In order to reduce stress to the patient the catheters were fixed so that they could stay in place during the total treatment series. The catheters, outer diameter 1.22 mm, were introduced through hollow needles under sterile conditions before the first hyperthermia session, and fixed using Histo-acryl (tissue adhesive) and Tegaderm (transparent adhesive). Recently, the data concerning the first 180 catheters placed in 74 treatment areas were evaluated. In one patient, an abscess developed 10 days after removal of the (3) catheters, which required surgical intervention, but it was not clear whether these problems had developed as a result of catheter placement. There were no problems with 139 of the remaining 177 catheters (79 per cent) and in 50 treatment fields (68 per cent), respectively, for a duration of 9-55 (mean 23) days. Ten catheters (6 per cent) were lost during the treatment series after 1-22 (mean 10) days. With 28 catheters (16 per cent) infection was observed, 14-27 (mean 19) days after insertion, which necessitated catheter removal before the last treatment session in 11 cases (6 per cent). The complication rate decreased with increasing experience; from 29 per cent (25/85) in the early period to 14 per cent (13/92) in the later period. We conclude that the use of closed-tip catheters under proper control generally causes few, if any, problems. This results in the acquisition of a substantial amount of reliable temperature data at reproducible sites, and it is well tolerated by the patient.

Adenocarcinoma↗

PubMedDate not supplied

Radiofrequency capacitive heating of deep-seated tumours using pre-cooling of the subcutaneous tissues: results on thermometry in Dutch patients.

The capacity of a radiofrequency, 13.56 MHz, capacitive hyperthermia system using extensive pre-cooling of the subcutaneous tissue to induce locoregional deep heating has been investigated in 11 patients. Tumour location was presacral in nine--and eccentric towards the lateral side of the pelvis in two patients. For thermometry multiple catheters (mean 2.7) were inserted into the treatment volume. The mean numbers of temperature measuring points per treatment were 9.4 in tumour, 5.5 in muscle and 7.2 in subcutaneous fat. RF energy was applied after 30 min of cooling through two flexible boli perfused with saline water at 5-10 degrees C. Patient tolerance to pre-cooling was very good and after some initial discomfort the patient became rapidly accustomed to the cold water boli. For some patients better temperatures were achieved when the conventional anterior-posterior applicator set-up was replaced by a set-up with an applicator on each lateral side of the patient. As patients can tolerate temperatures within the fat tissue as high as 45.5 degrees C without complaining it appears important to monitor the temperature at the transition of fat to muscle tissue to prevent subcutaneous burns. The study shows that pre-cooling cannot avoid preferential heating at the interface from fat to muscle tissue. In this patient group the quality of the hyperthermia treatment appeared to be rather poor: 60% of the measured tumour temperatures were below 40 degrees D.

Adipose Tissue↗

PubMedDate not supplied

Some practical notes on documentation of superficial hyperthermia treatment.

A detailed and accurate documentation of the treatment setup of each individual hyperthermia session is extremely important for retrospective data analysis as well as treatment quality control. In this paper the relatively simple and cheap documentation system developed by the Hyperthermia Department of the Dr Daniel den Hoed Cancer Center, is presented.

Humans↗

PubMedDate not supplied

Risk of tumour growth along thermometry catheter trace: a case report.

A patient with recurrent rectal cancer was treated with the combination of radiotherapy plus hyperthermia. Intratumoral thermometry probes were introduced within closed-tip catheters, inserted through the buttocks under computed tomography (CT) control. Catheters were fixed to the skin to stay in place during the whole treatment series. At the end of the radiotherapy series, tumour progression was apparent. Seven months following treatment, tumour growth was visible at the insertion site of one of the catheters. This finding indicates that catheters should not be placed outside the treatment volume involved in any locally curative treatment.

Adenocarcinoma↗

PubMedDate not supplied

Risk of acute hypotension following epidural analgesia during deep regional hyperthermia: a case report.

A potentially dangerous complication occurring during deep regional hyperthermia is described. A patient receiving epidural analgesics for pain caused by a large pelvic recurrent rectal tumour was treated by hyperthermia induced by electromagnetic radiation. The epidural infusion pump failed during heating and further analgesics were administered by bolus injections into the epidural space. Following the second bolus injection, a severe drop in arterial blood pressure was observed. The most likely multifactorial pathogenesis is discussed and measures to avoid such an event are recommended.

Analgesia, Epidural↗

PubMedDate not supplied

Modification of human tumour and normal tissue pH during hyperthermic and normothermic antiblastic regional isolation perfusion for malignant melanoma: a pilot study.

Human tumour and normal tissue pH were investigated during hyperthermic and normothermic antiblastic regional isolation perfusion and the effects of vascular occlusion, artificially induced hypoxia, hyperglycaemia, haemoglobin level of the perfusate and hyperthermia on tumour and normal tissue pH were evaluated. A pilot study was performed on 10 patients, with locally inoperable recurrent and primary malignant melanoma of the leg. The treatment consisted of a regional isolation perfusion with hyperthermia (120 min at 42-43 degrees C), at femoral level, followed by a normothermic regional isolation perfusion with Melphalan (60 min at 37-38 degrees C), at iliacal level, 7-10 can be distinguished: (1) first ischaemic anoxia period; (2) extracorporeal circulation, during which the leg is heated to the desired temperature, after which either hyperthermia or Melphalan is applied; (3) second ischaemic anoxia period. During the anoxia periods the large vessels that supply the leg are temporarily clamped and the effects on tissue pH can be investigated. During extracorporeal circulation, high-dose glucose can be administered to the isolated leg, to acutely decrease tumour tissue pH. Such a decrease is expected to sensitize tumours to hyperthermia, when applied immediately prior to or during heating. At the beginning of the treatment the mean tumour pH was significantly lower than normal tissue pH (7.14, with a mean tumour volume of 39.2 cm3, and 7.38, respectively; p < 0.01). During the perfusions with hyperthermia and Melphalan, tissue pH decreased by -0.41 units and -0.20 for tumour, and -0.11 units for normal tissue, respectively (all statistically significant). The two anoxia periods accounted for approximately half of the net decrease. During these periods tumour pH appeared to decrease more selectively, although there was great variation. The other investigated modalities, such as hyperglycaemia and hyperthermia, also decreased tissue pH, but to a lesser extent. However, a combination of more than one modality caused a larger decrease than a single one, but no preference for tumour could be detected. Before the second perfusion mean tumour pH was significantly increased by 0.14 units, and was no longer significantly different from normal tissue pH in the course of the regional isolation perfusion. This could be the reflection of the reduced tumour volume (by 30%, n.s.). Similar pH changes occurred during this Melphalan perfusion, but they were less pronounced since the total treatment time was shorter. Summarizing, tumour pH can be decreased more than normal tissue pH in the course of the regional isolation perfusion. In particular, vascular occlusion appeared to be tumour pH selective.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗