Publications by authors named "Hoogenhout J"

Panic disorder is characterized by the paroxysmal occurrence and fear of bodily symptoms. In recent years it has been proposed that patients "learn" to fear cardiorespiratory sensations through interoceptive conditioning. This study sought to model the initial stage of this process in healthy volunteers (N=44) using mild cardiac sensations.

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Since the early 1970s, substantial progress in dealing with musculoskeletal tumours has been made, with improvements in surgical skills, radiology, chemotherapy, pathology, and radiotherapy. Nowadays, 70-85% of all malignant tumours are treated by limb salvage, without compromising the oncological result. After many years, the functional result that may be achieved with a limb-saving procedure is becoming clear.

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Purpose: To answer the question whether a single fraction of radiotherapy that is considered more convenient to the patient is as effective as a dose of multiple fractions for palliation of painful bone metastases.

Patients: 1171 patients were randomised to receive either 8 Gy x 1 (n = 585) or 4 Gy x 6 (n = 586). The primary tumour was in the breast in 39% of the patients, in the prostate in 23%, in the lung in 25% and in other locations in 13%.

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Purpose: to determine whether intraoperative radiotherapy causes long-term negative effects on the healing of colonic anastomoses in the rat.

Methods And Materials: 175 rats were divided into seven equal groups. One group served as sham-irradiated control group.

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Intraoperative irradiation appears to be a valuable addition to the modalities available to treat patients with large bowel cancer. However, its potential effect on healing of anastomoses has not been investigated extensively. For this purpose, male Wistar rats underwent colonic resection.

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Hyperthermia is a promising method for increasing the efficacy of radiation therapy of colorectal cancer. To study the histological aspects of healing of an anastomosis in the colon, after combined preoperative (sham) irradiation and (sham) hyperthermia treatment, 48 male Wistar rats were divided randomly into four groups. In each animal, a segment of the colon was treated successively by (sham) irradiation (single dose of 25 Gy X rays) and/or (sham) hyperthermia (44 degrees C, 30 min).

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Preoperative radiotherapy as an adjunct to surgery for rectal carcinoma is generally thought to impair the healing of colorectal anastomoses. To delineate the presumed hazards of preoperative irradiation, we investigated this effect in a new model where, in contrast to experiments reported so far, anastomoses were constructed using normal tissue for the proximal limb and irradiated tissue for the distal limb. A group of 120 male Wistar rats, divided randomly into 12 groups of 10 each, were used.

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There exists a growing interest in intra-operative radiation therapy as a treatment modality for large bowel cancer. In a previous experimental study we showed that high-dose intra-operative irradiation delays the healing of colonic anastomoses. However, the contribution of proteases is unknown.

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Background And Purpose: Preoperative irradiation with direct postoperative chemotherapy could benefit patients undergoing surgery for colorectal cancer. This study was designed to examine, in an experimental model, if such treatment is feasible without detrimental effects on early anastomotic healing.

Material And Methods: A colonic segment was irradiated (25 Gy) in 3 groups (n = 10 each) of male Wistar rats.

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Objective: To determine if a combination of preoperative irradiation and local hyperthermia of a colonic segment is detrimental to subsequent early anastomotic healing.

Design: A prospective randomized experimental trial.

Setting: An animal research laboratory.

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This paper describes 29 patients with Ewing's sarcoma of bone treated between 1975 and 1990 at the University of Nijmegen Hospital, Nijmegen, The Netherlands. Osteomyelitis was the primary diagnosis in 24%. Treatment consisted of chemotherapy in combination with surgery and/or radiotherapy.

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Background: There exists a growing interest in intraoperative radiation therapy as a treatment modality for large-bowel cancer. Since such therapy could interfere with wound repair, we investigated its effects on early healing of colonic anastomoses.

Methods: After resection of 1 cm of colon, rats were irradiated with a single dose of 25 Gy, either to the proximal limb (P group) or to both proximal and distal limbs of the bowel (PD group) before anastomotic construction.

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Unlabelled: A three-arm randomized trial was performed to assess the acute and late toxicity and the impact on survival of the combination high-dose, split-course radiotherapy with 30 mg/m2 cisplatin (cDDP) weekly, with 6 mg/m2 cisplatin daily compared to radiotherapy alone in patients with non-small cell lung cancer (NSCLC). The study started in May 1984 and was closed in May 1989 after 331 patients were randomised. The analysis was performed after a minimum follow-up period of 22 months.

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The Dutch Co-operative Head and Neck Oncology Group performed a retrospective, nationwide study of laryngeal cancer between 1975 and 1984. The results for T3 laryngeal cancer treated with primary laryngectomy (n = 137) with post-operative radiotherapy when indicated or planned combined (pre-operative) radiotherapy with laryngectomy (n = 113) are analysed. The disease-free survival independent prognostic factors were treatment modality (planned combined treatment fared better, P = 0.

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Purpose: Short-term effects of radiotherapy on the healing process of newly made colonic anastomoses are investigated by measuring the anastomotic strength in a rat model.

Methods And Materials: Four groups of Wistar rats were used. In all groups, rats underwent a 1 cm sigmoid resection with end-to-end anastomosis.

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Background And Methods: Cisplatin (cis-diamminedichloroplatinum) has been reported to enhance the cell-killing effect of radiation, an effect whose intensity varies with the schedule of administration. We randomly assigned 331 patients with nonmetastatic inoperable non-small-cell lung cancer to one of three treatments: radiotherapy for two weeks (3 Gy given 10 times, in five fractions a week), followed by a three-week rest period and then radiotherapy for two more weeks (2.5 Gy given 10 times, five fractions a week); radiotherapy on the same schedule, combined with 30 mg of cisplatin per square meter of body-surface area, given on the first day of each treatment week; or radiotherapy on the same schedule, combined with 6 mg of cisplatin per square meter, given daily before radiotherapy.

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Clinical protocols have been designed to combine platinum-based drugs and radiation in the treatment of cancer. The rationale for this approach has been developed from preclinical studies demonstrating that platinum compounds can potentiate the cytotoxic effects of radiation toward cells. In the present study multicellular spheroids derived from squamous cell carcinoma cell line HN-1 have been used to study the effects of both cisplatin and carboplatin when administered prior to, concurrently, and after irradiation treatment.

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Large tumours are in general more difficult to cure by radiation treatment than small tumours. Several factors may be responsible for this phenomenon which evolves during tumour growth. In an earlier study using squamous cell carcinoma cell line HN-1, we have shown in split-dose recovery experiments that the amount of sublethal damage repair is equal in spheroids of different diameters.

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The 3-dimensional culture of human tumor spheroids under standardized medium conditions may reveal information on specific biological parameters that could be masked in serum-supplemented media. Spheroids derived from human tumor cells are growth retarded in media free of serum. Ex-Cyte IV is a substance derived from human blood that can be used to improve growth in tissue culture.

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Induction of radioresistant tumor cells by previous irradiations may be a problem because the chance to treat a patient presenting with a recurrence with radiotherapy may be lost if a resistant subpopulation was induced by the initial treatment. We here report on experiments with two squamous carcinoma cell lines where cultures were initially irradiated with graded single doses (2-6 Gy) and were re-irradiated after 4 days with single and split doses (2-6 Gy). Both cell lines showed no alteration in radiosensitivity.

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Cells from two human cell lines were irradiated both as multicellular tumor spheroids (MTS) and in monolayer culture. Radiation response of MTS was quantified in terms of specific growth delay and proportion cured, and as clonogenic cell survival for monolayer cells. Radiation was applied either as a single or as a split dose with time intervals of 1, 2, and 4 h to determine the rate of sublethal damage repair.

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Melanoma and lung adenocarcinoma may be amenable for radiotherapy if it were possible to increase the presently used total dose. In order to investigate this, spheroids from two cell lines of human origin, one obtained from a BRO melanoma and one from an NCI-H125 lung adenocarcinoma were exposed to graded doses (3-9 Gy) of radiation with 18-MV photons. Radiation was applied either as a single dose or as split doses with an interval of 6 h to determine the extent of sublethal damage repair.

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Growth curves of two human tumour cell lines grown as multicellular tumour spheroid (MTS) were used to obtain survival estimates by back-extrapolation after split and single dose irradiation. Neuroblastoma (NB-100) and squamous cell carcinoma (HN-1) single cells from monolayer culture were assessed for repair of sublethal and potentially lethal damage. The extent of repair was calculated on an iso-effect basis.

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