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Biomedical subjects

W T van der Graaf

Publications and source records attributed to W T van der Graaf.

At least 19 recordsLinked to original sources
PubMed2003

[Imatinib, a specific tyrosine-kinase inhibitor, for the treatment of patients with a gastrointestinal stroma cell tumor].

The c-kit oncogene, encoding for a transmembrane growth-factor receptor with tyrosine-kinase activity (KIT), plays an important role in the tumourigenesis of gastrointestinal stroma-cell tumours (GISTs). GISTs are a heterogeneous group of mesenchymal tumours, mainly localised in the abdomen. Immunohistochemical staining using antibodies directed towards the c-kit protein on the cell surface, is a useful tool in the often difficult differential diagnosis of GISTs from other mesenchymal tumours. The correct diagnosis of GISTs is crucial for the new treatment option with imatinib, the tyrosine-kinase inhibitor specifically targeted against KIT. The clinical development of imatinib for patients with GISTs has been extraordinarily rapid. As a result of the short period of time between the drug's experimental introduction and actual registration, many unanswered questions about its use for the treatment of GISTs remain. These can only be answered in well-designed clinical trials. It is therefore recommended that patients with these rare tumours are referred to a centre with experience in the diagnosis and treatment of these soft-tissue sarcomas.

Antineoplastic Agents↗
PubMed2002

Tamoxifen effects on subjective and psychosexual well-being, in a randomised breast cancer study comparing high-dose and standard-dose chemotherapy.

To evaluate the impact of tamoxifen on subjective and psychosexual well-being in breast cancer patients in relation to type of prior chemotherapy and menopausal status. Longitudinal interview study in breast cancer patients during and after adjuvant tamoxifen use. Menopausal status was defined by last menstrual period and serum oestradiol and FSH levels. Gynaecology outpatient clinic, Tertiary Referral Hospital, January 1995 to September 1999. Breast cancer patients <56 years of age, participating in a randomised trial comparing adjuvant high-dose (n=45) and standard-dose (n=53) chemotherapy, followed by radiotherapy and tamoxifen. Relative incidence and correlation of subjective and psychosexual symptoms during and after tamoxifen. During tamoxifen the most frequent complaints were hot flushes (85%), disturbed sleep (55%), vaginal dryness and/or dyspareunia (47%), decreased sexual desire (44%) and musculo-skeletal symptoms (43%). Disturbed sleep correlated with hot flushes (P<0.0005) and concentration problems (P<0.05). Decreased sexual interest correlated with vaginal dryness (P<0.0005) and/or dyspareunia (P<0.0005). In the high-dose group more patients became postmenopausal (95% vs 33%) and more patients reported symptoms than in the standard-dose group (P<0.05). After discontinuation of tamoxifen, symptoms decreased significantly. However, hot flushes, disturbed sleep and vaginal dryness persisted more often in patients who remained postmenopausal after high-dose chemotherapy (P<0.05). Overall, during tamoxifen patients reported many symptoms. More patients become postmenopausal after high-dose chemotherapy, and they remain often symptomatic after tamoxifen.

Adult↗
PubMed2001

Telomere length in breast cancer patients before and after chemotherapy with or without stem cell transplantation.

High-dose chemotherapy and peripheral blood stem cell transplantation (PBSCT) may accelerate telomere length loss in haematopoietic stem cells. As data including pre-and post-treatment samples are lacking, we studied leukocyte telomere length and telomerase activity before and after treatment in breast cancer patients randomized to receive 5 adjuvant courses FEC (5-FU, epirubicin and cyclophosphamide) (n = 17), or 4 x FEC followed by high-dose cyclophosphamide, thiotepa, carboplatin and autologous PBSCT (n = 16). Haemoglobin, MCV, leukocyte-and platelet numbers were assessed prior to (t(0)), 5 months after (t(1)) and 9 months after chemotherapy (t(2)); these parameters were decreased at t(1)and t(2)compared to t(0)(high-dose: all parameters; standard-dose: leukocytes and platelets), and all parameters were lower after high-dose than standard-dose treatment at t(1). Paired individual leukocyte samples of t(0)and t(1)showed telomere length change (determined by telomere restricted fragment (TRF) assay) ranging from +0.8 to -2.2 kb, with a decreased TRF length in 9 patients of both groups. Telomerase activity (determined by TRAP assay) was below detection limit in leukocyte samples of t(0)and t(1). Thus, standard-and high-dose chemotherapy negatively affect haematological reconstitution in this setting. In individual patients, telomere length can be remarkably changed following haematological proliferative stress after treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Prospective evaluation of early cardiac damage induced by epirubicin-containing adjuvant chemotherapy and locoregional radiotherapy in breast cancer patients.

PURPOSE: To evaluate prospectively the cardiotoxic effects of epirubicin-containing adjuvant chemotherapy in breast cancer patients. PATIENTS AND METHODS: Patients (median age, 46 years; range, 28 to 55 years) were treated with five cycles of fluorouracil, epirubicin (90 mg/m2), and cyclophosphamide (FEC) (group I, n = 21) or with four cycles of FEC followed by high-dose chemotherapy consisting of cyclophosphamide, thiotepa, and carboplatin (group II, n = 19). Locoregional radiotherapy was applied subsequently. Cardiac evaluation was performed before chemotherapy (T0), 1 month after chemotherapy, 1 month after radiotherapy (T2), and 1 year after start of chemotherapy (T3). Left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography and diastolic function by echocardiography. Autonomic function was assessed by 24-hour ECG registration for heart rate variability (HRV) analysis. Time-corrected QT (QTc) was assessed and N-terminal atrial natriuretic peptide (NT-ANP) and brain natriuretic peptide (BNP) were measured as biochemical markers of cardiac dysfunction. RESULTS: No patient developed overt congestive heart failure (CHF) and the mean LVEF declined from 0.61 at T0 to 0.54 at T3 (P =.001), resulting in an LVEF below 0.50 (range, 0.42 to 0.49) in 17% of the patients, whereas 28% had a decline of more than 0.10. Plasma NT-ANP levels increased gradually from 237 pmol/L at T0 to 347 pmol/L at T3 (P <.01), whereas plasma BNP levels increased from 2.9 pmol/L to 5.1 pmol/L (P =.04). Mean QTc increased from 406 msec at T0 to 423 msec at T3 (P <.01). No persistent alterations were found in diastolic function and HRV. CONCLUSION: Relatively low doses of epirubicin in adjuvant chemotherapy for breast cancer results in mild subclinical myocardial damage demonstrated by a decline in LVEF, an increase in natriuretic peptide levels, and an increase in QTc, which may indicate a long-term risk of CHF.

Adult↗
PubMed2001

Expression of P-glycoprotein, multidrug resistance-associated protein 1, and lung resistance-related protein in human soft tissue sarcomas before and after hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan.

BACKGROUND: Multidrug resistance (MDR) is associated with expression of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and lung resistance-related protein (LRP). Tumor necrosis factor (TNF-alpha) is able to modify the expression of these three proteins in different cell types. The effect of TNF-alpha in the clinical situation on patients with soft tissue sarcomas (STS) is indeterminate. METHODS: Thirty-seven patients with a locally advanced extremity STS underwent hyperthermic isolated limb perfusion (HILP) with TNF-alpha and melphalan; 15 patients received additional interferon gamma. Clinical and histologic responses were documented and used to define the overall response. Samples before and after HILP were analyzed immunohistochemically for P-gp, MRP1, and LRP. Samples were scored as negative or positive (< or = 5% or > 5% positive tumor cells). RESULTS: Six patients had an overall complete response, 25 patients had a partial response, and 4 patients with STS revealed no change; in 2 patients, the response remained unclear. The percentage STS samples that were positive for all three proteins dropped from 92% before HILP to 85% after HILP. P-gp positive samples were encountered more often than MRP1 positive samples (P < 0.05). The percentage of samples that were negative for all three MDR proteins increased after HILP from 6% to 16%. MDR status had no significant correlation with tumor response. CONCLUSIONS: HILP with TNF-alpha and melphalan results in excellent overall tumor response in patients with locally advanced STS. STS more often are positive for P-gp than for MRP1. MDR status in patients with STS is not predictive for tumor response after HILP. Data from the current study suggest that the combination of TNF-alpha and melphalan does not induce MDR positive STS: a result with clinical importance when consecutive, adjuvant, doxorubicin-containing chemotherapy is considered.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Improved long term survival of patients with metastatic nonseminomatous testicular germ cell carcinoma in relation to prognostic classification systems during the cisplatin era.

BACKGROUND: The current study reviews chronologic changes in the long term outcome of patients with metastatic nonseminomatous testicular germ cell tumors (NSTGCT) who were treated at a single institution during the past two decades. The 10-year survival of prognostic subgroups according to the classification of the International Germ Cell Consensus Classification Group (IGCCCG) and various other prognostic classifications is examined in time to evaluate whether cumulative experience has led to an improved outcome of patients with metastatic NSTGCT and to explore differences in outcome of prognostic subgroups. METHODS: Two hundred ninety-nine patients with metastatic NSTGCT who were treated with cisplatin-based polychemotherapy during the period from 1977 to 1996 were staged retrospectively according to the Royal Marsden (RM) classification and the following prognostic classifications: IGCCCG, Indiana, Medical Research Council (MRC), and European Organization for Research and Treatment of Cancer (EORTC). The numbers of patients who were treated during the periods 1977-1986 and 1987-1996 were 146 and 153, respectively. Survival curves were constructed using the Kaplan-Meier method, and disease specific 10-year survival rates of prognostic subgroups treated during the two consecutive 10-year periods were compared using the log rank test. RESULTS: The median follow-up of surviving patients during the periods 1977-1986 and 1987-1996 was 14.7 years (range, 0.2-20.6 years) and 7.0 years (range, 0.4-11.4 years), respectively. The actuarial disease specific 10-year survival rate of patients with metastatic NSTGCT increased from 76% during the period 1977-1986 to 88% during the period 1987-1996 (relative risk [RR], 0.51; 95% confidence interval [95% CI], 0.29-0.89; P < 0.05). The 10-year survival rates of patients with good, intermediate, and poor prognoses according to the IGCCCG classification were 95%, 74%, and 37%, respectively, during the period 1977-1986 and 94%, 87%, and 66%, respectively, during the period 1987-1996. Patients with a poor prognosis according to the IGCCCG classification showed the greatest increase in 10-year survival (RR, 0.43; 95% CI, 0.18-1.04; P = 0.06). Analysis using the RM, Indiana, and EORTC classifications also showed an improved 10-year survival rate of patients with a poor prognosis who were treated during 1987-1996 compared with those who were treated during 1977-1986. CONCLUSIONS: The 10-year survival rate of patients with metastatic NSTGCT who were treated with cisplatin-based chemotherapy significantly increased from 76% during the period 1977-1986 to 88% during the period 1987-1996. This improvement during the cisplatin era resulted mainly from an increase in the survival of patients with metastatic disease who had a poor prognosis. These results indicate that the management of patients with NSTGCT is still improving.

Adolescent↗
PubMed2001

Susceptibility to development of Mycobacterium ulcerans disease: review of possible risk factors.

Mycobacterium ulcerans disease, also known as Buruli ulcer (BU), is a disease of subcutaneous fat tissue. BU is prevalent in riverine and swamp areas of the tropical zone in Africa, Asia and South America, and a few scattered foci in Australia. The mode of transmission of M. ulcerans has not been fully elucidated, but inoculation into the subcutaneous tissues probably occurs through penetrating skin trauma. BU has not been linked with HIV infection. Antimycobacterial drug treatment is ineffective, and treatment is surgical. Patients eventually develop scars and contractures, with resulting disabilities, and the disease imposes a large burden on affected populations. The incidence of BU has dramatically increased in West African countries over the last decade. There is an urgent need for research into host and environmental risk factors for BU in order to develop effective strategies to combat this disease. We review possible genetic host susceptibility factors for BU that are relevant in other mycobacterial diseases: natural resistance-associated macrophage protein-1 (NRAMP-1), HLA-DR, vitamin D3 receptor, mannose binding protein, interferon-gamma (IFN-gamma) receptor, tumour necrosis factor alpha (TNF-alpha), interleukin (IL)-1 alpha, 1 beta and their receptor antagonists; and IL-12. Schistosoma haematobium infection is highly endemic in many BU foci in West Africa, with a striking increase in transmission after river dams were constructed. This observation, and the observations from interaction of schistosomiasis and tuberculosis, have fueled our hypothesis that schistosomiasis is a risk factor for BU by driving the host immune response towards a predominantly Th-2 pattern, away from a Th-1 preponderant protection against mycobacterial infection. If the latter hypothesis is confirmed, enhanced schistosomiasis control should impact on BU.

Carrier Proteins↗
PubMed2001

PNU-145156E, a novel angiogenesis inhibitor, in patients with solid tumors: a phase I and pharmacokinetic study.

Our aim was to establish, in patients with solid tumors, the dose-limiting toxicity, maximum tolerated dose (MTD), and pharmacology of PNU-145156E, a new sulfonated distamycin A derivative that blocked circulating angiogenesis-promoting growth factors in animal studies and exhibited an antitumor effect in murine solid tumors. In a Phase I study, PNU-145156E was administered i.v. every 6 weeks. Included were patients with solid tumors; an Eastern Cooperative Oncology Group performance score </=1; and normal bone marrow, renal, and liver functions and blood clotting tests. Excluded were patients with brain metastases or on steroid medication. Toxicity was scored with the National Cancer Institute Common Toxicity Criteria. Plasma and urine PNU-145156E was measured for pharmacokinetic analysis. The effect of PNU-145156E on serum basic fibroblast growth factor (bFGF) was measured by sandwich ELISA. Twenty-nine patients (median age, 54 years; range, 33-71 years; 19 males and 10 females; median performance score = 1) were treated at dose levels of 100-1050 mg/m(2). We observed, during 47 treatment cycles, erratic but short-lasting decreases of antithrombin III levels (<75%) at all dose levels. Other clotting tests remained normal except during thromboembolic events. Dose-limiting toxicity was thrombophlebitis, pulmonary embolism, and grade 3 dyspnea. PNU-145156E disappeared from the circulation, decreasing triexponentially with a long terminal half-life of 1 month. No significant change in bFGF and no objective tumor responses were observed. Disease stabilization was achieved in four patients. In conclusion, the MTD of PNU-145156E was 1050 mg/m(2). Serum bFGF level was not affected by PNU-145156E up to the MTD.

Adult↗
PubMed2000

Soft tissue leiomyosarcomas and malignant gastrointestinal stromal tumors: differences in clinical outcome and expression of multidrug resistance proteins.

PURPOSE: Several studies have reported clinical behavior and chemotherapy resistance in leiomyosarcomas, but these studies did not differentiate between soft tissue leiomyosarcomas (LMS) and malignant gastrointestinal stromal tumors (GIST). Multidrug resistance (MDR) has been associated with the expression of P-glycoprotein (P-gp), multidrug resistance protein (MRP(1)), and lung resistance protein (LRP). The aim of the present study was to compare LMS and GIST with respect to clinical outcome and MDR parameters. PATIENTS AND METHODS: Clinical outcome was evaluated in 29 patients with a primary deep-seated LMS and 26 patients with a primary malignant GIST. Paraffin-embedded material, available for 26 patients with LMS and 25 with GIST, was used for immunohistochemical detection of P-gp, MRP(1), LRP, and c-kit. RESULTS: Mean overall survival (OS) was 72 months for LMS patients and 31 months for GIST patients (P: <.05). Metastases occurred in 16 (59%) of 27 assessable LMS patients and in 10 (56%) of 18 assessable GIST patients. LMS predominantly metastasized to the lungs (14 of 16 patients), whereas GIST tended to spread to the liver (five of 10 patients) and the abdominal cavity (three of 10 patients; P: <.001). P-gp and MRP(1) expression was more pronounced in GIST than in LMS (P: <.05): the mean percentage of P-gp expressing cells was 13.4% in patients with LMS and 38.4% in patients with GIST, and the mean percentage MRP(1) expressing cells was 13.3% in patients with LMS and 35.4% in patients with GIST. LRP expression did not differ between LMS and GIST. c-kit was expressed in 5% of the LMS patients and in 68% of the GIST patients. CONCLUSION: LMS patients have a better survival than GIST patients, and the metastatic pattern is different. Expression of MDR proteins in LMS is less pronounced than in GIST.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Long-term chemotherapy-related cardiovascular morbidity.

As a consequence of the successful use of chemotherapy in the treatment of curable neoplasms such as germ cell tumours and malignant lymphomas, and the increasing application of primary and adjuvant chemotherapy for various tumour types, the number of patients with a prolonged life expectancy after treatment is rising. Attention to long-term side-effects, including cardiovascular toxicity, is therefore of growing importance. In this review we evaluate the literature on long-term cardiovascular toxicity related to chemotherapy in adult patients. Two categories of patient with favourable life expectancy have been reviewed, namely patients cured of metastatic disease by chemotherapy and patients treated with adjuvant chemotherapy. In the first category, the literature on long-term cardiovascular morbidity in survivors of metastatic testicular cancer and lymphomas is discussed, while in the second category this is done for patients treated with adjuvant chemotherapy for breast and colon cancer. As well as the direct toxic effects of chemotherapy on the cardiovascular system, the indirect toxic effects such as chemotherapy-related metabolic changes that may cause cardiovascular morbidity are also discussed.

Adult↗
PubMed2000

The blood-brain barrier and oncology: new insights into function and modulation.

The efficacy of chemotherapy for malignant primary or metastatic brain tumours is still poor. This is at least partly due to the presence of the blood-brain barrier (BBB). The functionality of the BBB can be explained by physicochemical features and efflux pump mechanisms. An overview of the literature is presented with emphasis on oncology. The BBB consists of capillary endothelial cells that lack fenestrations and are connected together with continuous tight junctions, with a high electrical resistance. Permeability of tight junctions can be increased in vitro by contraction of the cytoskeleton, caused by bradykinin agonists. Different efflux pumps are present in the BBB. Examples are P-glycoprotein (P-gp), organic anion transporters, (OAT) and multidrug-resistance-associated proteins (MRP)(1 and 3). These pumps act as a multi-specific efflux pump for various chemotherapeutic drugs. Experiments have shown that P-gp can be inhibited by different non-chemotherapeutic substrates such as cyclosporin A. The functionality in vivo of P-gp can be measured with positron emission tomography and [(11)C]-verapamil or with single photon emission computer tomography and(99m)Tc-sestamibi. MRP(1)and MRP(3)act as organic anion transporters that in vitro act as efflux pumps for substances that are conjugated or co-transported with glutathione and glucuronide, respectively. Methotrexate has been recently demonstrated to be transported by MRP(1)and MRP(3). Results of studies which demonstrate the clinical relevance and applicability of BBB modulators are eagerly awaited.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

A phase I study of a new polyamine biosynthesis inhibitor, SAM486A, in cancer patients with solid tumours.

Because tumour cell proliferation is highly dependent upon up-regulation of de-novo polyamine synthesis, inhibition of the polyamine synthesis pathway represents a potential target for anticancer therapy. SAM486A (CGP 48664) is a new inhibitor of the polyamine biosynthetic enzyme S-adenosylmethionine decarboxylase (SAMDC), more potent and specific than the first-generation SAMDC inhibitor methylglyoxal (bis) guanylhydrazone (MGBG). Preclinical testing confirmed promising antiproliferative activity. In this phase I study, SAM486A was given 4-weekly as a 120 h infusion. 39 adult cancer patients were enrolled with advanced/refractory disease not amenable to established treatments, PS </= 2, adequate marrow, liver, renal and cardiac function. Doses were escalated in 100% increments without toxicity in 24 pts from 3 mg m(-2)cycle(-1)up to 400 mg m(-2)cycle(-1). At 550 and 700 mg m(-2)cycle(-1)reversible dose-limiting neutropenia occurred. Other toxicities included mild fatigue, nausea and vomiting. No objective remission was seen. Pharmakokinetic analysis showed a terminal half-life of approximately 2 days. AUC and Cmax were related to dose; neutropenia correlated with AUC. The recommended dose for further phase II studies on this schedule is 400 mg m(-2)cycle(-1).

Adenosylmethionine Decarboxylase↗