Biomedical subjects

I De Wever

Publications and source records attributed to I De Wever.

At least 37 records · Page 2Linked to original sources

PubMed2000

Intimal hyperplasia after long-term venous catheterization.

OBJECTIVE: Intimal hyperplasia is a well-known consequence of arterial injury and arterialization in vein grafts. However, the subacute and chronic vein wall changes which occur after catheterization have not been well studied. In this animal study, intimal hyperplasia in the vein wall after catheterization was examined. METHODS: A silicon catheter was placed in the anterior caval vein of 54 rats. After in situ fixation at scheduled intervals (1 day to 6 months), the pathologic changes in the vein wall were studied on semi-serial histology sections by means of light microscopy. RESULTS: Three forms of intimal hyperplasia could be observed: plaque-like, papillary-like and incorporation of the mural part of the sleeve into the underlying vein wall. Although the appearance of each was different, their composition was identical. All were mainly composed of alpha-actin-positive cells and collagen localized above the internal elastin layer, and covered by endothelium if facing the lumen. The plaque-like and papillary-like forms were mainly localized in the anterior vena cava, while sleeve incorporation mainly occurred in the jugular vein. Plaque-like and papillary-like intimal hyperplasia could be seen together on the same slide, but these two forms were never seen together with sleeve incorporation. CONCLUSION: Intimal hyperplasia occurs after venous catheterization and is probably caused by chronic injury to the vein wall due to knocking and rubbing movements of the catheter against the wall.

Actins↗

PubMed2000

Neoadjuvant chemotherapy versus primary debulking surgery in advanced ovarian cancer.

Primary surgical cytoreduction followed by chemotherapy usually is the preferred management of advanced (stage III or IV) ovarian cancer. The presence of residual disease after surgery is one of the most important adverse prognostic factors for survival. Neoadjuvant chemotherapy has been proposed as an alternative approach to conventional surgery as initial management of bulky ovarian cancer, with the goal of improving surgical quality. Since 1989, we have been treating advanced epithelial ovarian cancer with neoadjuvant chemotherapy instead of primary cytoreductive surgery in approximately half of the patients with stage III-IV disease. Selection of neoadjuvant chemotherapy was based on disease-related characteristics (eg, metastatic tumor load, stage of disease, performance status). Since 1993, open laparoscopy also has been used to aid in evaluating operability. A retrospective analysis of 338 patients was conducted to compare outcomes during 1989 to 1998, when neoadjuvant chemotherapy was used, with those observed during 1980 to 1988, when all patients underwent primary cytoreductive surgery. Crude 3-year survival rates were higher and postoperative mortality rates were lower during the second time period compared with the first. Overall, the results suggest that neoadjuvant chemotherapy results in survival rates in selected patients with advanced ovarian cancer that are comparable with those associated with primary cytoreductive surgery. Patients with stage IV disease, total metastatic tumor load greater than 1,000 g, uncountable plaque-shaped peritoneal metastases, and/or a poor performance status are probably the best candidates for this alternative approach. A prospective randomized study of neoadjuvant chemotherapy and primary cytoreductive surgery is ongoing.

Adult↗

PubMed1999

Proliferative myositis in a child.

A case of proliferative myositis in the lumbar paraspinal muscles in a 14-year-old boy is presented. Imaging investigations including plain radiograph, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), bone scan and positron emission tomography (PET) were suggestive of an inflammatory process such as myositis ossificans. The diagnosis was made by incisional biopsy. More pronounced edema, more muscle fiber necrosis and a higher cellularity were found compared to adult cases. The karyotype of the lesion was normal. Clinically, the mass disappeared spontaneously. After 24 months, asymptomatic bridging ossification between the third and fourth lumbar vertebrae was noted.

Adolescent↗

PubMed1999

The importance of magnetic resonance imaging in the diagnosis and treatment of diffuse lymphangioma.

In this study, we will investigate the importance of MRI in the diagnosis and treatment of diffuse lymphangioma. Twenty-nine patients with lymphangiomas were treated at the U.Z. Leuven between March 1988 and September 1997. They all underwent a total surgical excision of the lesion. A global recurrence rate of 34.45% corresponds with a recurrence rate of 30.76% found in literature. In our study, a remarkable difference in recurrence rates is noticed between cystic hygroma (5/19 patients or 26.39%) and the more diffuse types of lymphangioma (5/10 patients or 50%). On three patients, preoperative MRI was performed. All these illustrate the important role of MRI in the diagnosis of lymphangioma, namely the characteristic appearance of the lesions on T1- and T2-weighted images and the better visualization of the lymphangioma extent. In line with the high recurrence rates of diffuse lymphangiomas and the advantages of MRI of these lesions, the role of MRI in the treatment of diffuse lymphangiomas is discussed.

Adolescent↗

PubMed1998

Comparison of chromosomal patterns with clinical features in 165 lipomas: a report of the CHAMP study group.

Soft tissue lipomatous tumors are morphologically heterogeneous. Various morphologic features are associated with specific chromosomal patterns and clinical features such as age, sex, and tumor site, location, and size. Simple lipomas are known to be karyotypically heterogeneous, but this has not been correlated with clinicopathological features. In 165 cases of solitary soft tissue lipoma, short-term cultures were analyzed cytogenetically. The karyotypes were divided into the following groups: normal karyotype; 12q13-15 aberrations; 6p rearrangements; 13q rearrangements, 8q11-13 aberrations; ring or giant marker chromosomes or both; other aberrations. The tumors were reexamined morphologically without knowledge of the karyotypic or clinical data. An abnormal chromosomal pattern was observed in 129 of 165 cases (78%): in 75 of 90 (83%) lipomas in the extremities and in 43 of 63 (68%) trunk wall lipomas. Chromosomal aberrations were present in 69 of 90 (77%) subcutaneous tumors and in 59 of 64 (80%) deep tumors. A normal karyotype was twice as frequent in tumors in patients under 30 years of age than in those from older individuals (6 of 16 vs. 30 of 149, 40% resp. 20%). Apart from the finding that normal karyotypes were more common in patients younger than 30 years, there was no significant association between cytogenetic pattern and patient sex or age or tumor localization, size, or depth. The pathogenetic basis and clinicopathologic relevance (if any) of the cytogenetic subtypes among benign lipomas remain unexplained.

Adolescent↗

PubMed1998

Cytogenetic analysis of 46 pleomorphic soft tissue sarcomas and correlation with morphologic and clinical features: a report of the CHAMP Study Group. Chromosomes and MorPhology.

With the aim of identifying objective cytogenetic-morphologic correlations, we evaluated 46 pleomorphic soft tissue sarcomas (mainly diagnosed originally as malignant fibrous histiocytomas) with clonal chromosome aberrations both cytogenetically and morphologically as part of an international collaborative study. By detailed histopathologic examination, most cases could be categorized into specific tumor types. Eight sarcomas were diagnosed as lipogenic (4 pleomorphic, 1 combined pleomorphic and myxoid/round cell, and 3 dedifferentiated liposarcomas), 19 as myogenic [11 leiomyosarcomas, 1 rhabdomyosarcoma, 4 myosarcomas not otherwise specified (NOS), and 3 probable myosarcomas NOS], 8 as myxofibrosarcomas, 1 as a malignant peripheral nerve sheath tumor, 1 as malignant mesenchymoma, 1 as extraskeletal osteosarcoma, I as sarcoma resembling proliferative fasciitis, and 7 as pleomorphic sarcomas NOS. In a three-grade system, 10 tumors were grade 2 and 36 were grade 3. The majority had highly complex karyotypes. A total of 24 recurrent abnormalities (defined by their presence in at least five cases) were detected: ring chromosomes, homogeneously staining regions (hsr) and/or double minute chromosomes (dmin), and structural rearrangement of 22 different chromosome bands or regions. The frequency and distribution of the recurrent karyotypic features were uneven. Grade 3 tumors displayed, on average, more aberrations per case than did grade 2 tumors. Nine of the selected abnormalities, including hsr/dmin and rearrangements of 19p13 and 19q13, were found only among the high-grade tumors. When the tumors were subdivided according to lineage of differentiation, the highest frequency of aberrations was seen in pleomorphic sarcomas NOS, followed by myxofibrosarcomas, myogenic sarcomas, and lipogenic sarcomas. None of the selected rearrangements was, however, specific for any of these subgroups. The sole consistent cytogenetic-morphologic association was that all three dedifferentiated liposarcomas had multiple abnormal clones, at least one of which contained supernumerary ring chromosomes. Due mainly to karyotype complexity, it therefore seems unlikely that cytogenetic analysis can assist in the differential diagnostic subclassification of pleomorphic sarcomas, nor was there any clear-cut indication that the karyotypic picture could be used to predict clinical outcome. Although the mean number of recurrent chromosome aberrations was almost twice as high in sarcomas that gave rise to metastases as among those that did not, no particular aberration was restricted to either of the two subgroups.

Adult↗

PubMed1998

Neoadjuvant chemotherapy or primary debulking surgery in advanced ovarian carcinoma: a retrospective analysis of 285 patients.

OBJECTIVE: This study was aimed at comparison of neoadjuvant chemotherapy with primary debulking surgery in advanced ovarian carcinoma. METHODS: Retrospective analysis of 285 patients with advanced ovarian carcinoma treated between 1980 and 1997 was performed. RESULTS: In the period 1980-1988 all patients underwent primary debulking surgery and 82% were cytoreduced to less than 0.5 cm largest residual tumor mass (n = 112). Analysis of this group of patients showed that some subgroups of patients (e.g., Stage IV disease or a total metastatic tumor load of more than 1000 g prior to debulking surgery) had a poor survival despite cytoreduction to no or less than 1 g of total residual tumor load. The complication rate was high especially in the group with unfavorable prognosis (postoperative mortality, 6%). In the period 1989-1997 (n = 173) the patients were surgically evaluated to receive primary chemotherapy (43%) or primary debulking surgery (57%). Prognostic variables were similar for both treatment periods. The actuarial crude survival was higher in the second time period (3-year crude survival of 26% +/- 4. 3 and 42% +/- 4.6 for the first and second time periods, respectively; P = 0.0001). The postoperative mortality was 0% during the second time period. From 1993 on, the decision to give neoadjuvant chemotherapy or to perform primary debulking surgery in patients with clinically obvious metastatic disease was made with the help of an open laparoscopy (n = 77). Median duration of the laparoscopy, blood loss, and hospital stay due to this procedure were 25 min, 10 ml, and 2 days. Primary and interval debulking surgery was performed in 36 and 63% of this subgroup of patients, respectively. CONCLUSION: In this retrospective analysis over two different time periods, crude survival was higher when treating about half of the patients with advanced ovarian carcinoma with primary chemotherapy instead of primary debulking surgery. The role of neoadjuvant chemotherapy should be evaluated in a prospective randomized study.

Adult↗

PubMed1998

Translocation (X;1) reveals metastasis 31 years after renal cell carcinoma.

Cytogenetic investigation of a metastatic lesion appearing 31 years after nephrectomy allowed for the diagnosis of a renal cell carcinoma. The der(X)t(X;1)(p11.2;q21.1) found in this case and review of the 14 other cases previously reported indicates that this chromosome lesion may characterize a specific subgroup of renal cell carcinoma, with distinct histology and age distribution that also can occur in females.

Carcinoma, Renal Cell↗

PubMed1998

Composition and formation of the sleeve enveloping a central venous catheter.

PURPOSE: After catheterization, 42% to 100% of central venous catheters are surrounded by a "fibrin sleeve." This sleeve has been considered the cause of catheter-related infections, withdrawal occlusion, and pulmonary embolism. The reactions between the vein wall and the catheter were studied. METHODS: A silicone catheter was placed in the anterior caval vein of 123 rats. After in situ fixation at scheduled intervals, the pathologic changes were studied on semi-serial histologic sections by means of light microscopy, transmission electron microscopy, and scanning electron microscopy (SEM). In 36 rats, the catheter was withdrawn immediately; in 72 rats, it was left in situ up to 6 months; and in 15 rats, the study was performed up to 10 months after withdrawal of a catheter that had remained in situ for 6 months. RESULTS: In the group in which the catheter was withdrawn immediately, mural thrombi disappeared by day 7. In the group in which the catheter remained in situ, thrombi remained around the proximal portion of the catheter. This pericatheter thrombosis (PCT) was invaded by migrating and proliferating smooth muscle cells (SMCs), originating from an injured vein wall, and transformed from day 7 into a tissue composed predominantly of SMCs and collagen and covered by endothelial cells. Later, the number of cells decreased, and the relative amount of collagen increased. Up to 10 months after withdrawal of the catheter, the collapsed sleeve was still present within the vein. CONCLUSION: The sleeve around a central venous catheter is not a fibrin sleeve, but a stable cellular-collagen tissue covered by endothelium. It is mainly formed by smooth muscle cells migrating from the injured vein wall into the early pericatheter thrombus.

Animals↗

PubMed1998

Osteoid osteoma and osteoblastoma with clonal chromosome changes.

We cytogenetically investigated six osteoid osteomas, one osteoblastoma and one aggressive osteoblastoma, and observed clonal structural changes in one osteoid osteoma and in the aggressive osteoblastoma. Clonal chromosome changes had not been reported previously in osteoid osteoma, whereas the only reported chromosome change in osteoblastoma was different from the one presented here.

Adolescent↗

PubMed1998

[Primary retroperitoneal extragonadal germ cell tumor].

A case is presented of a primary extragonadal retroperitoneal germ cell tumor (seminoma) in a 51-year-old male. The ultimate diagnosis was only achieved after curative surgical resection of the tumor. There was no demonstrable testicular neoplasm.

Germinoma↗

PubMed1997

Cytogenetic analysis of subcutaneous angiolipoma: further evidence supporting its difference from ordinary pure lipomas: a report of the CHAMP Study Group.

Subcutaneous angiolipomas are benign soft-tissue lesions consisting of two mesenchymal elements (i.e., adipose tissue and blood vessels) and having distinct clinical features. They usually are multiple, with an obvious male predominance, and hereditary occurrence has been described. Twenty subcutaneous angiolipomas from 10 patients with typical clinical and morphologic features were reviewed. All lesions had a normal karyotype. This finding is in striking contrast with ordinary lipomas, spindle-cell and pleomorphic lipomas, lipoblastomas, and hibernomas, most of which have characteristic clonal chromosomal aberrations. The normal karyotype of subcutaneous angiolipoma as well as its distinct clinical and morphologic features suggest a different pathogenesis from pure lipomas.

Adult↗

PubMed1997

Soft tissue sarcoma in adults.

The importance of a multidisciplinary group in the treatment of soft tissue sarcomas is well established. This approach has led to a major shift in treatment from a single-modality radical surgery to a more sophisticated approach with limb-sparing resections integrated with external irradiation, interstitial irradiation, or both. The increasing knowledge of both the molecular mechanisms of sarcoma development and the biological characteristics (tumor cell proliferation, hypoxia, necrosis, angio-genesis) will enable us to predict prognosis on a more individual basis and thus allow for more selective treatment strategies. Studies relating these molecular markers and biological characteristics to treatment results obtained with surgery, radiotherapy, and chemotherapy are eagerly awaited.

Adult↗

PubMed1997

Prognostic significance of nm23 protein expression in malignant melanoma. An immunohistochemical study.

The NM23 genes, encoding for the red blood cell nucleoside diphosphate kinases A and B, have been found to serve as metastasis-suppressor genes in experimental animal models of tumour progression, and in some, but not all cancers in man. To investigate the role of NM23 in the progression of human malignant melanoma, we studied the expression and distribution of the nm23 protein with a sensitive immunohistochemical technique and a well-characterized monoclonal antibody in 41 benign pigment cell lesions and 71 uniformly treated malignant melanomas with a long follow up-up. In benign naevi, the junctional nests frequently expressed nm23 protein, whereas the immunoreactivity tended to decrease when the lesions matured. All malignant melanomas expressed nm23 protein in their vertical and/or radial growth phases, and the immunoreactivity tended to increase towards the deeper parts of the lesion. No relation was found between nm23 expression and patient outcome. In addition, nm23 was found in activated lymphoid cells, and this feature was significantly associated with a brisk lymphocytic stroma response in malignant melanomas. Our data are at variance with previous mRNA studies on malignant melanoma, and indicate that routine immunohistochemical analysis for nm23 protein on paraffin-embedded tumour tissue cannot reliably be used as a prognostic marker for patients suffering from malignant melanoma. In contrast, our findings suggest that the nm23 protein in pigment cell lesions is related to the proliferative or activated state of pigment cells, rather than to their metastatic potential.

Adult↗

PubMed1996

Duplication of chromosome segment 12q15-24 is associated with atypical lipomatous tumors: a report of the CHAMP collaborative study group. CHromosomes And MorPhology.

Ordinary lipomas are cytogenetically characterized by a variety of balanced rearrangements involving chromosome segment 12ql3-15, and atypical lipomatous tumors (ALT) by supernumerary ring chromosomes or giant markers known to contain amplified 12q sequences. In a series of 228 cytogenetically analyzed and histopathologically reexamined ordinary lipomas and ALT, 10 tumors showed unbalanced chromosome-12 aberrations. All 4 tumors with loss of segments from 12q were classified as ordinary lipomas, whereas 5 of the 6 tumors showing gain of 12q material were diagnosed as ALT. One or three extra copies of 12q15-q24 were present in all 5 ALT. We conclude that duplication of 12q sequences may be a sufficient level of amplification for development of the microscopic appearance that characterizes ALT.

Chromosome Aberrations↗

PubMed1996

Trisomy 21 in solitary fibrous tumor.

We found trisomy 21 as the sole chromosome abnormality in a solitary fibrous tumor arising at a nonpleural site. No cytogenetic investigation of solitary fibrous tumors has previously been reported.

Antigens, CD34↗

PubMed1996

Trisomies 8 and 20 in desmoid tumors.

A nonrandom occurrence of trisomy 8 and of trisomy 20 in desmoid tumors has been recently reported. The finding of trisomy 8 in nondividing desmoid tumor cells by in situ hybridization prompted us to evaluate, in a similar way, the occurrence of trisomy 20 and the possible occurrence of both trisomies together because their co-existence was cytogenetically observed in a few cases. Double fluorescence in situ hybridization (FISH) with centromeric probes for chromosomes 8 and 20 was performed on 16 single cell suspensions of desmoid tumors. FISH confirmed the occurrence of trisomy 8 or 20 in a single cell suspension of desmoid tumors. Both individual trisomies, and even more their association in the same cells, are rare to extremely rare in solid tumors in general and in mesenchymal tumors in particular, and are only known to occur in infantile fibrosarcoma.

Adolescent↗

PubMed1996

Temporary colostomy in supralevator pelvic exenteration. A comparative study between stapled loop and loop colostomy.

A temporary loop colostomy is created in most patients undergoing total supralevator pelvic exenteration with low rectal anastomosis. We report 16 patients comparing two different types of loop colostomy. In half of them a normal loop colostomy was made and refashioning of the stoma was necessary in two patients because of faecal spillover in the presence of anastomotic leakage. In the other eight patients a functional terminal colostomy was created by application of a TA 55 stapler on the efferent loop. In this group no refashioning of the stoma was necessary and no difficulties were encountered on closure of this type of colostomy. Because of the high incidence of anastomotic leakage in this population, the stapled loop colostomy is the preferred method of choice because it eliminates any possible faecal spillover.

Adult↗