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H Boot

Publications and source records attributed to H Boot.

At least 37 records · Page 2Linked to original sources
PubMed1998

Computer-based decision support in the management of primary gastric non-Hodgkin lymphoma.

Primary non-Hodgkin lymphoma of the stomach is a rare disorder for which clinical management has not yet been settled completely. Faced with the many uncertainties associated with the selection of a treatment for a patient with this disorder, it is difficult to determine the treatment that is optimal for the patient, as well as the prognosis to be expected. The development of a decision-theoretic model of non-Hodgkin lymphoma of the stomach is described. The model aims to assist the clinician in exploring various clinical questions, among others questions concerning prognosis and optimal treatment. Central to the model is a probabilistic network that offers an explicit representation of the uncertainties underlying the decision-making process. The model has been incorporated in a decision-support system. Preliminary evaluation results indicate that the performance of the model in its present form matches the performance of experienced clinicians.

Combined Modality Therapy↗
PubMed1997

Histological grading in gastric lymphoma: pretreatment criteria and clinical relevance.

BACKGROUND & AIMS: Stomach-conserving therapy in primary gastric non-Hodgkin's lymphoma (mucosa-associated lymphoid tissue [MALT]-NHL) is increasingly gaining importance as an alternative to surgery. As a consequence, surgical pathologists have to define histological criteria in pretreatment endoscopic biopsy specimen samples not only to make the diagnosis but also to recognize minor tumor components that may infer a significantly adverse impact on prognosis. The aim of this study was to define histological criteria for clinically significant tumor progression in pretreatment endoscopic biopsy specimens. METHODS: In a consecutive series of 106 patients with gastric MALT-NHL, the prognostic impact of large cell components was assessed by semiquantitative analysis of clusters and diffusely intermingled malignant blasts. RESULTS: In low-grade MALT-NHL, a category with a diffuse large cell component of 1%-10% with or without nonconfluent clusters of blasts could be separated with a significantly worse prognosis (10-year disease-specific survival, 90% vs. 75%). No clinical parameters of known prognostic significance could account for this difference. CONCLUSIONS: It is possible to define criteria in endoscopic biopsy specimens to recognize clinically relevant tumor progression. To serve as a guideline in the choice of treatment, these criteria should be validated prospectively in future clinical trials.

Adult↗
PubMed1997

Potential risks and artifacts of magnetic resonance imaging of self-expandable esophageal stents.

BACKGROUND: Several types of coated and uncoated self-expandable stents composed of various metals are available for palliation of malignant esophageal stenoses and fistulas. We encountered poor visualization of the mediastinum and skeletal axis with magnetic resonance imaging in a patient with a Gianturco self-expandable stent. METHODS: To evaluate potential problems, such as stent migration in the magnetic field of the magnetic resonance scanner (MRI) and artifacts in the images, we studied four types of expandable stents: the Ultraflex (titanium alloy), the covered Wall stent (nitinol), the Gianturco stent (Cook), and the modified Gianturco stent (Song)-the last two being made of stainless steel. RESULTS: An appreciable attraction force and torque, as measured ex vivo by suspending the stent in a Perspex device, was found for both Gianturco stents. In particular, the Gianturco (Cook) stent is pulled toward the head with a force of 7g; however, it is uncertain whether this is a potential risk for dislodgement. In addition, gross artifacts in the images, studied by putting the stents in a cylindric phantom filled with a diluted gadolinium solution, made the magnetic resonance useless for imaging in a wide area around the Gianturco stents of stainless steel. No problems with magnetic resonance image quality were encountered for the titanium-based Ultraflex and Wall stents. CONCLUSIONS: Specific information on the type of stent is necessary before a magnetic resonance imaging examination is planned.

Artifacts↗
PubMed1997

Uvulopalatopharyngoplasty for the obstructive sleep apnoea syndrome: value of polysomnography, Mueller manoeuvre and cephalometry in predicting surgical outcome.

Sixty consecutive patients with the obstructive sleep apnoea syndrome (53 men and seven women) were analysed by questionnaire, polysomnography, röntgenographic cephalometry and the Mueller manoeuvre before and 6 months after uvulopalatopharyngoplasty (UPPP), to assess the surgical outcome and the prognostic value of preoperative evaluation. Seventy-three per cent of patients reported improvement of snoring and 55% reported improvement of excessive daytime sleepiness. Thirty-five per cent showed a decrease of at least 50% in the desaturation index, and 13% had a postoperative desaturation index below 5. Although the improvement of desaturation parameters was marked in some patients, the overall change was not significant. Neither the Body Mass Index (BMI), nor any of the cephalometric variables were significantly correlated to surgical outcome. Increased difference in collapsibility between the soft palate and the base of the tongue showed a close to significant relation with the improvement of desaturation index. High desaturation index, low mean saturation and deep lowest saturation were found to be slightly predictive of improvement in nocturnal desaturation. In a multivariate analysis however no significant predictors could be identified. It is concluded that UPPP is effective in reducing snoring and daytime sleepiness over a 6-month follow-up period, but that the overall improvement in nocturnal desaturation is limited and difficult to predict. Further research is needed to evaluate the long-term efficacy of UPPP.

Body Mass Index↗
PubMed1996

Use of sheet color filters for video-endoscopic observation during intraluminal photodynamic therapy.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) is currently evaluated in clinical studies for the treatment of bronchial and oesophageal tumors. STUDY DESIGN/MATERIALS AND METHODS: Usually, a cylindrical diffuser is entered into the lumen via a flexible endoscope. Subsequently, the diffuser is positioned at the tumor location under direct- or video-endoscopic vision and manually kept in position by the clinician during the treatment. However, video endoscopes are saturated (overexposure) due to the intense light from the diffuser tip and scattered light from the tissue. This hinders continuous monitoring of the diffuser position. RESULTS: A simple color filter sheet, suitable for use with endoscopes with removable CCD-video head, appeared to be very effective in improving video endoscopic monitoring during treatment. CONCLUSION: The standard fiberoptic endoscopes with the accessory CCD video head are more suitable for PDT treatment monitoring than modern endoscopes with the integrated CCD camera.

Bronchial Neoplasms↗
PubMed1996

Modulation of toxicity following external beam irradiation preceded by high-dose rate brachytherapy in inoperable oesophageal cancer.

To induce fast relief of dysphagia in inoperable oesophageal cancer, we applied high-dose rate (HDR) intraluminal irradiation followed by external irradiation (EBRT) in a phase II study. 15 patients (group A: n = 15; 10 men, 5 women; median age 66 years) were treated with 10 Gy HDR brachytherapy plus 40 Gy EBRT (15 fractions of 2.67 Gy). Severe side-effects were encountered in 60% of patients: 3 late ulceration, 2 pending fistula, 2 fistula and 2 patients with fatal haemorrhage after an interval of 6 months. Overall response was excellent: 9 complete remissions (60%) and 6 partial responses (40%). Because of the high toxicity rate, in a subsequent study (group B: n = 30; 23 men, 7 women; median age 66 years) the EBRT scheme was changed using smaller fractions (2.0 Gy) to reach the same total dose of 40 Gy. The complication rate (17%) was significantly reduced, while the overall response remained excellent (83%): 17 complete and 8 partial responses. The impressive change in complication rate of HDR brachytherapy and EBRT stresses the impact of the fraction per dose and illustrates the small therapeutic margins.

Aged↗
PubMed1996

Combined diagnostic imaging with 131I-metaiodobenzylguanidine and 111In-pentetreotide in carcinoid tumours.

Carcinoid tumours derived from the neural crest are usually associated with the symptoms of flushing and diarrhoea in the presence of liver metastases. Scintigraphs with 131I-metaiodobenzylguanidine (131I-MIBG) which is accumulated in the argentaffin granules of the cell, as well as with 111In-pentetreotide for the imaging of somatostatin receptors on the cell surface, are positive in a large proportion of carcinoid patients. To evaluate the complementary role of both radionuclide tests, we studied 20 consecutive carcinoid patients: 14 with the characteristic carcinoid syndrome and 6 with tumour symptoms, such as pain or obstruction. A positive test was found in 84% with either 131I-MIBG or 111In-pentetreotide; the combination yielded a sensitivity of 95%. A positive correlation was found with the presence of the carcinoid syndrome, but not with 5-HIAA excretion. A positive test may help in adjusting treatment: either to predict the response to octreotide or to select patients for 131I-labelled MIBG treatment. Application of a therapeutic dose of 111In-pentetreotide may be limited by the high normal uptake in the kidneys.

3-Iodobenzylguanidine↗
PubMed1996

High dose rate brachytherapy before external beam irradiation in inoperable oesophageal cancer.

To induce fast relief of dysphagia in patients with oesophageal cancer high dose rate (HDR) brachytherapy was applied before external radiotherapy in a prospective study. Seventy-four patients with inoperable oesophageal cancer (36 squamous cell, 38 adenocarcinoma) were treated with a combination of 10 Gy HDR brachytherapy, followed by 40 Gy in 4 weeks external beam radiotherapy (EBRT), starting 2 weeks later. Tumour response, as measured by endoscopy and/or barium swallow, revealed complete remission in 21 and partial response in 38 patients (overall response rate 80%). Improvement of dysphagia was induced by brachytherapy within a few days in 39%, and achieved at the end of treatment in 70% of patients. Further weight loss was prevented in 39 of the 59 patients who presented with weight loss. Pain at presentation improved in 12 out of 25 patients. Median survival was 9 months. No differences in either response rate or survival were found in squamous cell or adenocarcinoma. Side-effects were either acute with minimal discomfort in 32 (42%) or late with painful ulceration in five patients (7%), occurring after a median of 4 months. A fistula developed in six patients, all with concurrent tumour. In conclusion, brachytherapy before EBRT was a safe and effective procedure to induce rapid relief of dysphagia, especially when combined with EBRT.

Adenocarcinoma↗
PubMed1996

Gastric non-Hodgkin lymphomas of mucosa-associated lymphoid tissue are not associated with more aggressive Helicobacter pylori strains as identified by CagA.

Primary gastric non-Hodgkin lymphoma of mucosa-associated lymphoid tissue (MALT-NHL) is strongly related to Helicobacter pylori (H pylori) infection. CagA positive H pylori strains appear to be more aggressive, as reflected by a greater degree of gastric inflammation and higher levels of Il-8 production. Using a polymerase chain reaction-based assay, cagA status was determined in H pylori strains of 12 patients with gastric MALT-NHL, 38 patients with peptic ulcer disease, and 39 patients with non-ulcer dyspepsia. CagA-positive H pylori strains were significantly more frequent in peptic ulcer disease than in non-ulcer dyspepsia (Fisher's exact test p <0.001). An increased frequency of CagA-positive strains was not identified in gastric MALT-NHL compared to non-ulcer dyspepsia patients (Fisher's exact test P <.3). Therefore, it can be concluded that infection with more aggressive strains is associated with the development of peptic ulcer disease, but plays a minor role, if any, in the development of gastric MALT-NHL.

Adult↗
PubMed1996

Primary non-Hodgkin lymphoma of the stomach: endoscopic pattern and prognosis in low versus high grade malignancy in relation to the MALT concept.

BACKGROUND: Various histological classifications developed for nodal lymphomas failed to be of value in extranodal lymphomas. More recently, gastric lymphoma is considered to represent a distinctive group derived from mucosa associated lymphoid tissue (MALT). AIM: To study the prognostic value of malignancy grading based on the concept that most gastric lymphomas are of MALT origin, the endoscopic as well as clinical characteristics in 114 patients with primary gastric non-Hodgkin's lymphoma were evaluated. RESULTS: In univariate analysis, patients with low grade lymphoma (n = 51) were younger, had less advanced stage, and less frequently bulky disease than those with high grade lymphoma (n = 63). In multivariate analysis weight loss and increased erythrocyte sedimentation rate were significantly less frequent in low grade (45% and 22%) compared with high grade lymphoma (75% and 53%). In low grade lymphoma endoscopic findings were often interpreted as a benign condition (27 of 51), in contrast with high grade lymphoma, where carcinoma was most frequently (37 of 63) suspected. In low grade lymphoma complete remission rate was 92%, and five year survival 75%, In high grade lymphoma results were significantly less favourable (p = 0.0001): complete remission in 68%, and a five year survival of 46%. CONCLUSION: Malignancy grading was strongly correlated with treatment outcome; endoscopically low grade lymphoma was often hard to distinguish from benign conditions, whereas high grade lymphoma often revealed carcinoma-like features.

Adult↗
PubMed1996

Upper airway patency and nocturnal desaturation in habitual snoring and obstructive sleep apnea: pathogenesis of sleep-related breathing disorders.

Sixty patients, 53 men and 7 women, referred for excessive snoring or suspected sleep apnea syndrome were analyzed by polysomnography, Mueller maneuver, cephalometric roentgenography, and pulmonary function testing, to evaluate the contribution of static and dynamic upper airway obstruction in the pathogenesis of sleep-related breathing disorders and OSAS. Desaturation index and maximal desaturation were used in the analysis as indicators of severity of sleep-related breathing disorders. Body Mass Index, increased collapsibility at the base of the tongue by the Mueller maneuver, increased distance between hyoid and mandibular plane, and increased soft palate diameters by cephalometry as well as a decreased peak inspiratory flow by pulmonary function testing were found to be related to increased oxygen desaturation parameters. In a multivariate analysis the significant obstruction parameters could explain only 37% of the variability of maximum desaturation and 31% of the variability of desaturation index, 63 and 69%, respectively, must therefore be explained by other mechanisms. We conclude that instability of respiratory and muscular control, possibly enhanced by sleep-phase-related changes, is more important in the pathogenesis of sleep-related breathing disorders than pure anatomic narrowing of the airway.

Adult↗
PubMed1996

Palliative effect of metaiodobenzylguanidine in metastatic carcinoid tumors.

PURPOSE: To evaluate the therapeutic effect of iodine-131-labeled metaiodobenzylguanidine (131I-MIBG) and unlabeled MIBG in patients with carcinoid tumor. MATERIALS AND METHODS: A therapeutic dose of 7.4 GBq (200 mCi) 131I-MIBG infused over 4 hours was administered to 30 patients with either carcinoid syndrome (n = 20) or tumor symptoms such as pain and fever due to carcinoid tumor (n = 10). In general, two courses were given, 6 weeks apart. Due to radioactivity, patients had to be isolated for 5 to 7 days. Subsequently, we studied the effect of unlabeled MIBG based on the possible pharmaceutic activity of MIBG and to avoid the isolation procedure. A doseescalation study of 8.5, 17, and 34 mg/m2 MIBG infused over 4 hours at 4-week intervals was performed in 20 patients with carcinoid syndrome who were not suitable for treatment with the radioactive compound. RESULTS: Following 131I-MIBG treatment, symptomatic responses were observed in 60% of patients (median duration, 8 months; maximum, 2 years). Side effects were mild and rapidly reversible in 16 patients, and were related to the isolation procedure in seven of these patients. Unlabeled MIBG resulted in symptomatic improvement in 60% of patients (median duration, 4.5 months). Side effects, which included changes in blood pressure, were mild and transient. Symptomatic responses were not accompanied by biochemical responses. CONCLUSION: Both MIBG treatment regimens were equally effective in the palliation of symptoms, but duration of response tended to be much longer with the radioactive compound. However, the unlabeled compound provided a simpler treatment, eg, in elderly patients and those in poor condition, without the need for isolation.

3-Iodobenzylguanidine↗
PubMed1995

Assessment of sucralfate coating by sequential scintigraphic imaging in radiation-induced esophageal lesions.

The value of mucosal protection with sucralfate in cases of gastric ulceration is well documented. Although sucralfate is advocated as treatment of esophageal lesions, we found it to be of limited value in the management of radiation-induced esophagitis; in a pilot study of 10 cases, minor relief of symptoms, with analgetics still required, was noted in 4 patients, and no improvement was seen at endoscopy after 6 weeks of treatment in any patient. To see if this might be the result of inadequate mucosal coating, we administered sucralfate labeled with technetium 99m to 26 patients with endoscopically proven esophagitis secondary to irradiation for esophageal carcinoma. The degree of coating was evaluated according to persistence of the radionuclide in the affected esophageal segment. Scans were performed at regular intervals for 120 minutes after administration of 150 MBq 99mTc-sucralfate. Although scans were positive for radioactivity in 24 of 26 (92%) patients, only 8 (31%) of these represented selective binding of sucralfate to tissue. In the other 16 cases, scans were positive for sucralfate and albumin, indicating nonspecific retention most likely caused by concomitant esophageal stenosis. Residual radioactivity was observed for 30 minutes or more in 11 (42%) patients, but scans were positive for radioactivity after 1 to 2 hours in only 4 (15%). The duration and intensity of tracer accumulation were similar in both acute lesions an chronic radiation damage. These findings suggest that the inability of sucralfate to alleviate irradiation-induced odynophagia may be related to insufficient duration of adherence of this compound to damaged esophageal mucosa.

Aged↗