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Biomedical subjects

T J van Vroonhoven

Publications and source records attributed to T J van Vroonhoven.

At least 19 recordsLinked to original sources
PubMed2001

[Lump in the neck: 4 patients with a medullary thyroid carcinoma].

In a 25-year-old man, medullary thyroid carcinoma (probably a solitary sporadic form) was diagnosed following investigation of a small lump in the patient's neck. This was removed and followed up with further treatment. In a 27-year-old man, episodes of headache, palpitations and excessive perspiration (due to a pheochromocytoma) and a positive family history of thyroid problems led to further investigations and the subsequent diagnosis of multiple endocrine neoplasia (MEN) type 2A. The patient died at 48 years of age as the result of liver metastases. A total thyroidectomy had been carried out on a 19-year-old man with familial medullary thyroid carcinoma. The calcitonin levels remained elevated, but no tumour residues could be found. A 16-year-old girl with MEN type 2B had also previously undergone surgery. Her main complaint consisted of persistent constipation. Thyroid carcinomas usually present as a nodule in the neck. In 25% of cases, medullary thyroid carcinoma is part of the MEN2 syndrome. The clinical approach for medullary thyroid carcinoma is based on pathological findings following fine needle aspiration biopsy. The results of DNA tests determine the course of treatment and the need for family testing. In families with a hereditary form, there is a clear genotype-phenotype correlation. Early diagnosis and treatment can improve life expectancy.

Adolescent↗
PubMed2001

The ileo neorectal anastomosis: an experimental study on development of the surgical technique and theoretical background.

OBJECTIVE: The keystones of surgical treatment of ulcerative colitis and familial adenomatous polyposis are resection of the diseased colon with either an ileostomy or restoration of oro-anal continuity with an ileo-anal pouch. The ileo pouch anal anastomosis however, has a 15-35% pouch-related complication rate, 10% failure rate and is accompanied by an unpredictable functional outcome. In order to reduce these unfavourable rates and to improve functional results an alternative surgical technique, the ileo neorectal anastomosis (INRA), was developed experimentally. MATERIALS AND METHODS: In an experimental study 12 Yorkshire-Dutch landpigs had a subtotal colectomy and rectal mucosectomy. Subsequently a vascularized ileal mucosa sling was created and transposed on to the denuded rectal muscular cuff in eight. In another four animals a non-vascularized mucosa sling was transposed. The covering ileostomy was closed after 3 weeks. Repeated endoscopies, histological examinations of mucosal biopsies and rectal compliance measurements were carried out to evaluate the functional result of the neorectum. RESULTS: The surgical procedure of the INRA was technically successful in this animal study. Repeated endoscopy and histology showed complete ileal mucosa ingrowth in the neorectum without severe fibrosis in the group of animals with a vascularized sling. At follow up after 1 year no colonic metaplasia had occurred. Measurements of the neorectal reservoirs in the group of animals with a vascularized INRA procedure showed a median 'maximum tolerated volume' of 338 ml (range 300-410 ml). CONCLUSION: The INRA is technically feasible and reproducible. The histologically proven survival of the vascularized ileal mucosa and development of a compliant neorectal reservoir make the INRA an interesting alternative restorative procedure. Avoidance of the pouch-related complications of the ileo pouch anal anastomosis by this procedure might herald a new era of restorative surgery.

Journal Article↗
PubMed2001

Impact of stereotactic large-core needle biopsy on diagnosis and surgical treatment of nonpalpable breast cancer.

INTRODUCTION: Stereotactic large-core needle biopsy is increasingly replacing needle-localized breast biopsy for the diagnosis of nonpalpable breast disease. In this prospective study, the impact of the introduction of this technique on diagnosis and surgical treatment of nonpalpable breast cancer was assessed in two hospitals in The Netherlands. PATIENTS AND METHODS: A total of 84 patients with nonpalpable breast cancer, diagnosed by means of stereotactic large-core needle biopsy (needle biopsy group) were compared with 80 patients diagnosed with nonpalpable breast cancer before the introduction of large-core needle biopsy. These patients were diagnosed by means of needle-localized open breast biopsy (control group). Clinical outcome measures evaluated included: duration of diagnostic and therapeutic intervals and number of surgical procedures required for complete surgical treatment. Subgroup analysis was performed for the category of microcalcifications without tissue distortion. RESULTS: For the needle biopsy group, the median interval between initial referral to the surgeon and the availability of histological diagnosis was 9 days and the interval between initial referral and complete surgical treatment was 31 days. These intervals were significantly longer for the control group (19 days and 44 days respectively); 75% of patients in the needle biopsy group were treated in a single step surgical procedure compared to 16% of the patients in the control group (67 vs 25% respectively for the subgroup). The mean number of surgical procedures required to complete surgical treatment was 1.31 for needle biopsy group vs 1.91 for the open biopsy group (1.46 vs 1.84 for the subgroup). CONCLUSION: Introduction of stereotactic large-core needle biopsy leads to a reduction of the time to diagnosis and the time to complete surgical treatment of nonpalpable breast cancer. It also reduces the number of surgical procedures required for complete surgical treatment of nonpalpable breast cancer. The benefits of large-core needle biopsy may also be anticipated for patients with microcalcifications without tissue distortion.

Adult↗
PubMed2001

Abdominal packing for surgically uncontrollable hemorrhage in ruptured abdominal aortic aneurysm repair.

Emergency surgery for ruptured abdominal aortic aneurysms is accompanied with massive blood loss and is correlated with high incidences of coagulopathy. Following established results with abdominal packing to control hepatic hemorrhage, we present this technique for uncontrollable hemorrhage in patients with ruptured abdominal aortic aneurysm. The experience with this technique in 46 patients is described.

Aged↗
PubMed2001

Functional results and visceral perception after ileo neo-rectal anastomosis in patients: a pilot study.

INTRODUCTION: To reduce pouch related complications after restorative proctocolectomy, an alternative procedure was developed, the ileo neo-rectal anastomosis (INRA). This technique consists of rectal mucosa replacement by ileal mucosa and straight ileorectal anastomosis. Our study provides a detailed description of the functional results after INRA. PATIENTS AND METHODS: Eleven patients underwent an INRA procedure with a temporary ileostomy. Anorectal function tests were performed two months prior to and six and 12 months after closure of the ileostomy and comprised: anal manometry, ultrasound examination, rectal balloon distension, and transmucosal electrical nerve stimulation (TENS). Function was subsequently related to the histopathology of rectal biopsy samples. RESULTS: Median stool frequency decreased from 15/24 hours (10-25) to 6/24 hours (4-11) at one year. All patients reported full continence. Anal sensibility, and resting and squeeze pressures did not change after INRA. Rectal compliance decreased (2.1 (0.7-2.8) v 1.5 (0.4-2.2) and 1.4 (0.8-3.7) ml/mm Hg (p=0.03)) but the maximum tolerated volume increased (70 (50-118) v 96 (39-176) (NS) and 122 (56-185) ml (p=0.03)). Decreasing rectal sensitivity was found: the maximum tolerated pressure increased (14 (8-24) v 22 (8-34) (NS) and 26 (14-40) (p=0.02)) and the rectal threshold for TENS displayed a similar tendency. All patients displayed a low grade chronic inflammatory infiltrate in neorectal biopsy samples before closure of the ileostomy, with no change during follow up. CONCLUSIONS: The technique of INRA provides a safe alternative for restorative surgery. Stool frequency after INRA improves with time and seems to be related to decreasing sensitivity and not to histopathological changes in the neorectum. Furthermore, after the INRA procedure, all patients reported full continence.

Adenomatous Polyposis Coli↗
PubMed2001

Minimally invasive surgery for solitary parathyroid adenomas in patients with primary hyperparathyroidism: role of US with supplemental CT.

PURPOSE: To determine the role of ultrasonography (US) with supplemental computed tomography (CT) in patients with primary hyperparathyroidism who undergo minimally invasive surgery instead of conventional neck exploration. MATERIALS AND METHODS: US and CT were performed in 61 consecutive patients with primary hyperparathyroidism (part 1) to identify and localize solitary adenomas for resection by means of minimally invasive surgery and to provide a surgical road map. In part 2, involving 33 consecutive patients, CT was performed only when no solitary adenoma was identified with US or for road map information. Minimally invasive surgery was considered successful when serum calcium levels normalized and remained stable. RESULTS: In part 1, 46 definite solitary adenomas were found with US and two additional ones with CT. Minimally invasive surgery was successful in 45 patients and failed once. In part 2, US helped identify 23 solitary adenomas, and CT helped to find one. Minimally invasive surgery was successful in 22 patients and failed in two. Combined results in 94 patients demonstrated successful minimally invasive surgery in 67 (71%), with 64 of them selected with US alone (95% CI: 61, 80). The sensitivity of US in the diagnosis of solitary adenoma was 78% (95% CI: 67%, 86%), with a positive predictive value of 96% (95% CI: 88%, 99%). CONCLUSION: US examination of patients with primary hyperparathyroidism allowed successful selection for minimally invasive surgery in more than two-thirds of the cases, with additional CT useful chiefly for surgical road mapping.

Adenoma↗
PubMed2001

Risk factors for cancellation of stereotactic large core needle biopsy on a prone biopsy table.

Among patients undergoing stereotactic needle biopsy of the breast on a prone biopsy table, a substantial proportion of planned procedures are terminated prematurely. This study was undertaken to identify risk factors for cancellation of these procedures and to derive a clinical rule for predicting cancellation. Risk factors for cancellation were assessed in a group of 476 consecutive patients with non-palpable lesions planned for large core needle biopsy. 64 (13%) of these planned procedures were cancelled. Multivariate regression analysis was applied to identify independent risk factors for cancellation. Validation took place by applying the logistic rule on a validation set, including 5 cancelled and 35 successful biopsy procedures. Mammograms that were difficult to interpret owing to extremely dense breast tissue, axillary location of the non-palpable lesion, body mass index below 20, less than 15 mm distance from the lesion to the chest wall or the presence of more than one non-palpable lesion were identified as independent risk factors. The logistic rule discriminated patients with successful and cancelled biopsy procedures with a receiver operator characteristic (ROC) area of 0.72. In the validation set, the area under the ROC curve was 0.92. The prediction rule, based on mammographic and clinical findings, discriminated patients with successful and cancelled needle biopsy procedures to a certain extent. The risk of cancellation of the stereotacic biopsy procedure is considerable in cases of very dense breast tissue or the presence of multiple risk factors.

Biopsy, Needle↗
PubMed2001

Peroperative measurement of PTH in the management of primary hyperparathyroidism.

UNLABELLED: This study was performed to prospectively evaluate the efficacy of a newly developed, non-expensive and non-commercial perioperative PTH-assay as indicator of successful surgery in minimally invasive adenomectomy (MIA) for primary hyperparathyroidism (pHPT). METHODS: A chemoluminescence-based PTH-assay was modified to significantly shorten the incubation time, producing results in a total of 45-60 minutes. Its reliability was tested in 19 patients undergoing MIA for pHPT. Patients were selected for MIA based on preoperative imaging including ultrasound and CT. After verification of its reliability, the PTH assay was incorporated into our treatment protocol and its results registered and correlated with serum calcium levels and surgical outcome. RESULTS: The PTH assay was found to fully correlate with the current gold standard, i.e. serum calcium levels on the first postoperative day after MIA. It was subsequently used in 55 patients selected for MIA, as well as in 26 patients undergoing conventional neck exploration (CNE). In all cases it correctly indicated surgical failure/success. The conventional re-exploration that was required in 3 patients after unsuccessful MIA, was also correctly interpreted on the basis of the PTH-assay. In 2 cases an unexpected delay was encountered in the decline of PTH-levels following adenomectomy. CONCLUSION: The perioperative PTH-assay described is a reliable, inexpensive, and relatively fast predictor of surgical outcome, and should be considered essential for minimally invasive surgery in patients with pHPT.

Adult↗
PubMed2001

Angiostatin inhibits pathological but not physiological retinal angiogenesis.

PURPOSE: Antiangiogenic treatment is a promising new therapy for angiogenesis-dependent diseases. In the current study, the biologic effects on pathologic and physiological angiogenesis in the retina of angiostatin, a very potent angiogenesis inhibitor were determined. In addition, the effects of angiostatin on the growth and development of newborn mice were examined. METHODS: Oxygen-induced retinopathy was induced by subjecting mice postnatal day (P)7 to hyperoxic conditions (5 days) followed by normoxic conditions (relative hypoxia). Mice were treated with angiostatin (intravitreal or systemic). Retinal blood vessels were visualized by fluorescein angiography. Retinal neovascularization was assessed by counting intravitreal endothelial cell nuclei. Growth and organogenesis were determined between P0 and P14. RESULTS: Relative hypoxia resulted in intravitreal proliferation of retinal blood vessels. However, proliferation was inhibited completely by systemic administration of angiostatin without affecting normal retinal vascularization. After intravitreal injection of angiostatin, pathologic proliferation of the retinal blood vessels was impaired by 62%. Neither systemic nor intravitreal treatment impaired the development or growth of organs throughout the body. CONCLUSIONS: Angiostatin inhibits oxygen-induced intravitreal pathologic retinal angiogenesis without affecting the development of physiological retinal vascularization, development, and growth of newborn mice. Therefore, antiangiogenic treatment may be a useful tool in the treatment of proliferative retinopathies.

Angiostatins↗
PubMed2000

[Diverse expression of multiple endocrine neoplasia type 1].

MEN-1 is an autosomal dominantly inherited disorder, characterised by the occurrence of multiple tumours, particularly in the parathyroid glands, the pancreatic islets, the pituitary gland and the adrenal glands, as well as by neuroendocrine carcinoid tumours. Various clinical manifestations are presented by description of three patients harbouring a MEN1 gene germline mutation. A 44-year-old man had symptoms of hyperparathyroidism and in addition to parathyroid adenomas proved to have tumours in the thymus, adrenal and pituitary glands. A 48-year-old woman from a family with MEN-1 had suffered since her 40th year from headache and heartburn; she appeared to have adenomas in the parathyroid glands and gastrinomas in the pancreas, leading to a Zollinger-Ellison syndrome. One of her relatives, a man aged 29, had suffered from childhood from convulsions due to attacks of hypoglycaemia, and an insulinoma was assessed. In all patients, surgical and/or medical treatment alleviated symptoms. Clearly, the position or nature of the mutations in the MEN1 gene do not correlate with the clinical expression of the disease. Family investigation, DNA analysis and periodic examination improve quality of life and the life expectancy.

Adult↗
PubMed2000

Continuous administration of angiostatin inhibits accelerated growth of colorectal liver metastases after partial hepatectomy.

Human plasminogen-derived angiostatin is one of the most potent antiangiogenic agents currently known. However, it is unclear whether angiostatin is also effective against accelerated tumor growth induced by local up-regulation of growth factors, including angiogenesis stimulators, such as in regenerating liver. Prior to addressing this question, we tested, in mice, whether continuous administration of angiostatin could improve its biological effects. This assumption was based on the relatively short half-life of angiostatin in mice, as well as on the theoretical necessity to suppress tumor-induced angiogenesis continually. The findings presented here clearly indicate continuous administration to be superior to the conventional twice-daily bolus injections. Using the maximally effective regimen of 100 mg/kg/day via s.c. pump infusion, we found angiostatin to not only suppress s.c. primary tumors but also to significantly inhibit the outgrowth of colorectal hepatic metastases in resting liver and even to inhibit accelerated tumor growth in regenerating liver after 70% partial hepatectomy. In conclusion, angiostatin could play an important role in patients subjected to partial hepatectomy to prevent outgrowth of residual micrometastases, provided it is administered continuously to obtain maximal biological effects.

Angiostatins↗
PubMed2000

[The operating room of the future].

Advances in computer technology will revolutionize surgical techniques in the next decade. The operating room (OR) of the future will be connected with a laboratory where clinical specialists and researchers prepare image-guided interventions and explore the possibilities of these techniques. The virtual reality is linked to the actual situation in the OR with the aid of navigation instruments. During complicated operations the images prepared preoperatively will be corrected during the operation on the basis of the information obtained peroperatively. MRI currently offers maximal possibilities for image-guided surgery of soft tissues. Simpler techniques such as fluoroscopy and echography will become increasingly integrated in computer-assisted peroperative navigation. The development of medical robot systems will make possible microsurgical procedures by the endoscopic route. Tele-manipulation systems will also play a part in the training of surgeons. Design and construction of the OR will be adapted to the surgical technology, and include an information and control unit where preoperative and peroperative data come together and from where the surgeon operates the instruments. Concepts for the future OR should be regularly adjusted to allow for new surgical technology.

Diagnosis, Computer-Assisted↗
PubMed2000

GIP-dependent adrenal Cushing's syndrome with incomplete suppression of ACTH.

ACTH-independent Cushing's syndrome may be due to the development of ectopic hormone receptors in adrenal tissue. Thus, in food-dependent Cushing's syndrome the adrenals aberrantly express receptors for gastric inhibitory polypeptide (GIP). We present the case of a 60-year-old woman with food-dependent Cushing's syndrome whose cortisol levels increased after stimulation with CRH. In this patient with Cushing's syndrome the finding of low basal plasma cortisol levels in the late night and early morning as well as a paradoxical rise of plasma cortisol during a 7-h infusion with dexamethasone (carried out without any restriction in food intake), suggested that cortisol production was stimulated at times of food intake. Hourly measurements of plasma cortisol for 48 h revealed prominent meal-related peaks. A plasma cortisol response, elicited by oral glucose administration, could be prevented by octreotide. Plasma ACTH was low or undetectable. CRH administration was followed by a ACTH response from 3 to 16 ng/l and a plasma cortisol response from 230 to 680 nmol/l. Octreotide treatment for nearly five months induced a partial clinical and biochemical remission. Total bilateral adrenalectomy was performed. The left adrenal was grossly enlarged (7 x 5.5 x 4 cm) and the right adrenal was slightly enlarged (6 x 4 x 1.8 cm). Microscopy revealed bilateral nodular hyperplasia. Cell suspensions of adrenal tissue from the patient did respond in a dose-dependent fashion to stimulation with GIP and were very sensitive to stimulation with synthetic ACTH1-24. However, CRH had no significant effect on cortisol production in vitro. Using RT-PCR amplification and cDNA hybridization, GIP receptor was found to be overexpressed in the left and right adrenal tissues from this patient as compared to adrenal tissues from a normal individual or from non GIP-dependent adrenal Cushing's syndrome. There was no evidence of presence of adrenal CRH receptors. Thus, in this patient with food-dependent Cushing's syndrome, the CRH-induced plasma ACTH and cortisol response is probably mediated by an incomplete suppression of the HPA axis as a result of the intermittent food-dependent nature of Cushing's syndrome.

Adrenal Cortex↗
PubMed2000

Diagnostic accuracy of large-core needle biopsy for nonpalpable breast disease: a meta-analysis.

For the evaluation of non-palpable lesions of the breast, image-guided large-core needle biopsies are increasingly replacing needle-localized open breast biopsies. In this study, the diagnostic accuracy of this minimally invasive technique was evaluated by reviewing the available literature. Five cohort studies were included in a meta-analysis. Sensitivity rate, histological agreement between needle biopsy and subsequent surgery or long-term mammographic follow-up and clinical consequences for different disease prevalences were assessed. The sensitivity rate of large-core needle biopsy for the diagnosis of breast cancer was high (97%). The reclassified agreement rate between core biopsy and subsequent surgical biopsy or long-term mammographic follow-up was also high (94%). In case of 20% breast cancer prevalence among women referred after screening (as in the US), the risk of breast cancer despite benign large-core needle biopsy result is less than 1%. In European countries, however, prevalence of breast cancer among referred women is 60-70%. This would result in a risk of breast cancer despite benign large-core needle biopsy result of 4-6%. The results of this meta-analysis indicate that the image guided large-core needle biopsy is a promising alternative for the needle localized breast biopsy. However, additional research is needed to explore the limiting factors of the technique. Without such detailed knowledge, a benign histological diagnosis on large-core needle biopsy in countries with high prevalence of malignancy among referred women should be interpreted with caution.

Biopsy, Needle↗
PubMed2000

Twelfth rib resection: a direct posterior surgical approach for subphrenic abscesses.

OBJECTIVE: To assess the results of twelfth rib resection as a direct posterior surgical approach to subphrenic abscesses in case of failure of percutaneous drainage, abandonment of percutaneous drainage in view of a too high risk of perforation of adjacent organs, or contamination of the pleural space, or an inaccessible abdomen. DESIGN: Retrospective study. SETTING: University hospital, The Netherlands. PATIENTS: 17 patients who required rib resection for subphrenic abscesses that developed after infected necrotising pancreatitis, splenectomy, or anastomotic disruption. INTERVENTIONS: 18 rib resections. MAIN OUTCOME MEASURES: Outcome and morbidity. RESULTS: Twelfth rib resection was successfully in 13 of 17 patients. Four patients died from multiple organ failure despite subsequent (re) laparotomies for additional surgical drainage. CONCLUSION: Twelfth rib resection can be useful for the treatment of subphrenic abscesses in selected patients.

Adult↗
PubMed2000

Open management of the abdomen and planned reoperations in severe bacterial peritonitis.

OBJECTIVE: To assess the results of open management of the abdomen and planned re-operations in severe bacterial peritonitis after perforation or anastomotic disruption of the digestive tract. DESIGN: Retrospective study. SETTING: University Hospital, The Netherlands. SUBJECTS: 67 consecutive patients. INTERVENTIONS: Open management of the abdomen and planned reoperations. MAIN OUTCOME MEASURES: Hospital morbidity and mortality, long-term follow-up. RESULTS: 38 patients developed multiple organ failure (MOF), but 29 needed only ventilatory and inotropic support. The mean number of re-operations was nine. 16 patients developed severe bleeding and 16 fistulas. In-hospital mortality was 42% (n = 28). Long-term morbidity, particularly the number of abdominal wall defects (n = 10), was considerable. CONCLUSION: Despite open management of the abdomen and planned re-operations, mortality of severe bacterial peritonitis still continues to be too high, and both short and long-term morbidity are appreciable. The value of open management of the abdomen and planned re-operations rests only on the clinical observation that other conventional surgical treatments of severe bacterial peritonitis often fail.

Abdomen↗