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Biomedical subjects

N H Mulder

Publications and source records attributed to N H Mulder.

At least 73 records · Page 4Linked to original sources
PubMed1998

Pelvic exenteration for advanced primary rectal cancer in male patients.

Between November 1987 and January 1996 pelvic exenteration for primary rectal cancer was carried out in 11 male patients. Two underwent a primary resection with subtotal cystectomy. In the remaining nine patients, the treatment commenced with a staging laparotomy and the fashioning of an end colostomy of the descending colon, followed by preoperative radiotherapy (50-56 Gy in 5 weeks). Total exenteration with uretero-ileo-cutaneostomy was carried out 4-6 weeks later. In two patients, the exenteration was performed despite the detection of hepatic metastases during the second laparotomy. The pathological staging was T4 in six and T3 in five patients. The immediate postoperative course was uneventful in eight patients and their hospital stay averaged 20 days. Serious postoperative complications prolonged the hospital stay of three patients. Three died during the first 6 months. Recurrent disease caused the death of three of the eight remaining patients: one locoregional (7.5 years after surgery), one from pre-existing hepatic metastases (18 months after surgery) and one from the combination of locoregional and distant recurrence (15 months after surgery). Four patients are on follow-up without evidence of disease, 96, 43, 23 and 22 months after surgery. One patient is alive 20 months after exenteration, with two pulmonary metastases having been recently excised. We conclude that, notwithstanding the morbidity rate, total pelvic exenteration is an acceptable option for advanced primary rectal cancer in male patients. Preoperative radiotherapy should be administered for cancers seated in the lower two-thirds of the rectum and perioperative chemotherapy should be considered seriously.

Adult↗
PubMed1997

Effects of an inducible anti-sense c-myc gene transfer in a drug-resistant human small-cell-lung-carcinoma cell line.

Small-cell-lung-cancer (SCLC) is characterized by rapid development of resistance to cytotoxic agents, such as cisplatin (cDDP) and anthracyclines. c-myc over-expression is one of the reported genetic alterations in this tumor. Amplification of the c-myc gene in this and other cancers is often correlated with poor prognosis. We studied the existence of a correlation between resistance and activation of the c-myc oncogene in a cDDP-resistant SCLC sub-line, GLC4cDDP, containing a c-myc gene amplification. This cell line was stably transfected with either an anti-sense c-myc (AS) or control (C) expression vector resulting in the sub-clones GLC4cDDP/AS and GLC4cDDP/C respectively. PCR and RT-PCR analysis illustrated the integration and activation of the dexamethasone(dex)-inducible MMTV-LTR promoter linked to the complete AS-c-myc fragment in GLC4cDDP/AS cells, but not in GLC4cDDP/C cells. Dex-induced AS-c-myc RNA resulted in 50% growth inhibition during the first 48 hr, which declined to 25% at 72 hr. In addition, AS-c-myc RNA expression reduced the cloning efficacy by 36% and induced 2-fold more apoptosis within 24 hr in GLC4cDDP/AS cells. Dex treatment did not affect the proliferation, clonogenicity and induction of apoptosis in the control cell lines. Furthermore, AS-c-myc RNA expression caused a 1.4-fold increased cDDP sensitivity but no change in doxorubicin or vincristine sensitivity in GLC4cDDP/AS cells. Our results indicate that AS-c-myc RNA expression causes inhibition of cell proliferation, induces apoptosis, reduces clonogenicity and interferes with cDDP sensitivity but not with doxorubicin or vincristine sensitivity.

Carcinoma, Small Cell↗
PubMed1997

Effect of low-dose oral etoposide on serum CA-125 in patients with advanced epithelial ovarian cancer.

The effect of oral etoposide on CA-125 serum levels was evaluated in 17 patients with epithelial ovarian cancer and progressive disease during, or relapsing after, prior chemotherapy. Only three patients had measurable lesions at extraperitoneal sites. Five had no measurable lesions. The oral etoposide dose was 50 mg b.d. for 7 days every 3 weeks, escalating to 10 or 14 days and continued until clinical progression. CA-125 after 4 courses was compared to baseline (CA-125 ratio). The rate of change of CA-125 (s, slope of the exponential regression curve) during the first 4 courses was compared to s over a similar period before treatment. One patient had a clinical partial response. Two other patients had a biochemical response (CA-125 ratio <0.5). Although the biochemical response rate was modest (12.5%), a decrease of s was observed in 14/16 patients (P = 0.02). The mean change of s represented an increase of mean doubling time from 52 to 693 days. No patients were withdrawn because of toxicity. General malaise, nausea, diarrhea, and anemia were the most important side effects. At the given dose schedule, oral etoposide shows activity in advanced ovarian cancer if the rate of change of CA-125 is used as a measure of activity.

Administration, Oral↗
PubMed1997

Synthetic oligonucleotides: useful molecules? A review.

Specific inhibition of mammalian genes is possible through the use of antisense oligonucleotides (AS ODNs) or ribozymes. These strategies have led to a better understanding of several cellular and molecular mechanisms, among which cancer development. Recently, these strategies have been applied also for therapeutical purposes in diseases such as AIDS and cancer. In some of these therapeutical trials the antisense strategy is combined with gene transfer technology: the AS ODN or the ribozyme are expressed within the cell by the use of adenoviral or retroviral vectors. However, many difficulties have still to be overcome before ODNs and ribozymes can be used routinely in the clinic.

Animals↗
PubMed1997

Randomized comparison of etoposide pharmacokinetics after oral etoposide phosphate and oral etoposide.

Etoposide phosphate is a water-soluble prodrug of etoposide. The plasma pharmacokinetics of etoposide following oral administration of etoposide phosphate or oral etoposide were compared. Seventeen patients with solid tumours were enrolled to receive oral etoposide phosphate 125 mg m(-2) on days 1-5 every 3 weeks, with escalation to 175 mg m(-2) from course 3 when possible. Patients were randomized to receive oral etoposide phosphate or oral etoposide on day 1 of course 1 and the alternative compound on day 1 of course 2. Fifteen patients received two or more courses and were evaluable for pharmacokinetic comparisons. The median AUC(inf) (area under the concentration vs time curve from zero to infinity) of etoposide was 77.7 mg l(-1) h after etoposide phosphate (95% CI 61.3-100.5) and 62.0 mg l(-1) h after oral etoposide (95% CI 52.2-76.9). The difference in favour of etoposide phosphate was borderline significant: median 9.9 mg l(-1) h (95% CI 0.1-32.8 mg l(-1) h; P = 0.05). However, the inter-patient variability of etoposide AUC(inf) was not improved (coefficients of variation 42.3% and 48.4%). Etoposide phosphate was undetectable in plasma after oral administration. Toxicities of oral etoposide phosphate were not different from those known for etoposide. In conclusion, oral etoposide phosphate does not offer a clinically relevant benefit over oral etoposide.

Administration, Oral↗
PubMed1997

A quantitative reverse transcriptase polymerase chain reaction-based assay to detect carcinoma cells in peripheral blood.

The presence of tumour cells in the circulation may predict disease recurrence and metastasis. To improve on existing methods of cytological or immunocytological detection, we have developed a sensitive and quantitative technique for the detection of carcinoma cells in blood, using the reverse transcriptase polymerase chain reaction (RT-PCR) identifying transcripts of the pancarcinoma-associated tumour marker EGP-2 (KSA or 17-1A antigen). The amount of EGP2 mRNA was quantified using an internal recombinant competitor RNA standard with known concentration and which is both reversely transcribed and co-amplified in the same reaction, allowing for a reliable assessment of the initial amount of EGP2 mRNA in the sample. Calibration studies, seeding blood with MCF-7 breast carcinoma cells, showed that the assay can detect ten tumour cells among 1.0 x 10(6) leucocytes. The PCR assay revealed that normal bone marrow expresses low levels of EGP2 mRNA, although immunocytochemistry with the anti-EGP2 MAb MOC31 could not identify any positively stained cell. Analyses using this RT-PCR assay may prove to have applications to the assessment of circulating tumour cells in clinical samples.

Antigens, Neoplasm↗
PubMed1997

Immunocytochemical analysis of cisplatin-induced platinum-DNA adducts with double-fluorescence video microscopy.

To detect low-level DNA platination, a sensitive immunocyto- and histochemical technique was developed using a polyclonal antibody. The antibody GPt, derived after immunization of rabbits with highly platinated DNA and purified with affinity chromatography, detected the main platinum (Pt)-containing intrastrand and interstrand adducts. Double-fluorescence microscopy image analysis was used to quantify Pt-DNA adducts with Hoechst 33258 fluorescence to locate the nuclei and with fluorescein isothiocyanate fluorescence to measure the immunosignal. A two- to five-fold dose-dependent difference in the level of cisplatin (CDDP)-induced Pt-DNA adducts between a CDDP-sensitive and -resistant human tumour cell line was detected. Large differences in Pt-DNA adduct levels after in vitro CDDP incubation between human buccal cells, lymphocytes and biopsies of different tumour types were observed. Pt-DNA adduct levels were fivefold higher in human testicular tumours than in colon tumours, representing CDDP-sensitive and -resistant tumours, respectively, in the clinic. These data suggest the possibility of predictive testing by measuring Pt-DNA adduct levels. Pt-DNA adducts in patients after treatment with CDDP were shown in normal buccal cells and in imprints of fresh tumour biopsies as well as in paraffin-embedded tumour cells. The analysis of Pt-DNA adducts at a single-cell level in small samples of normal and tumour cells during and/or after treatment is feasible with GPt and will hopefully enable more selective treatment of patients.

Animals↗
PubMed1997

Cardiotoxicity from intensive chemotherapy combined with radiotherapy in breast cancer.

Cardiac function was evaluated in 86 breast cancer patients after standard chemotherapy, followed by ablative chemotherapy and chest irradiation. One patient died of subacute heart failure 3 months after ablative chemotherapy. At a minimum of 1 year's follow-up (range 1-11 years) left vertricular ejection fraction (LVEF) was marginally abnormal in 4 of 27 disease-free survivors. One exceptional patient who received two transplantations is alive, with serious heart failure occurring after the second ablative chemotherapy. Including this patient, the percentage of patients free of clinical and subclinical cardiac dysfunction at 7 years is 78% (95% CI 61-95%). After ablative chemotherapy, cardiotoxicity was rarely life-threatening. The impact of subclinical cardiotoxicity in the long term is not clear and needs continued evaluation.

Adult↗
PubMed1997

A new in vitro assay for quantitation of chemotherapy-induced mucositis.

Patients receiving high-dose chemotherapy (HD-CT) are at risk of severe mucositis. Most prevention studies evaluate the degree of mucositis on clinical, and therefore subjective, measurements. The aim of this study was to develop an objective in vitro assay of chemotherapy-induced mucositis. Twelve patients with locally advanced breast carcinoma received HD-CT followed by peripheral stem cell reinfusion. Before and twice weekly after HD-CT, the mucosa was evaluated by an oral washing, a buccal smear and the World Health Organization (WHO) toxicity grading; furthermore, blood leucocyte levels were determined. For the oral washings, the percentage of viable epithelial cells was determined by trypan blue dye exclusion and leucocytes were counted by fluorescence microscopy after incubation with acridine orange. Maturity of buccal cells was assessed by staining buccal smears for morphology according to Papanicolaou (Whitacker D and Williams V, 1994). Eight healthy volunteers served as controls. The mean percentage (+/- s.e.m.) of viable oral epithelial cells was stable in controls (44 +/- 2%). In patients, they increased after HD-CT, which was significant after day 7 compared with pretreatment (P < or = 0.05). In addition, a shift from mature to immature epithelial cells in buccal smears was observed. Oral leucocyte levels were closely correlated with the blood leucocyte counts. The WHO score followed the results of these other evaluations with some delay. The viability of buccal cells obtained by oral washings increases after HD-CT. This is possibly because of desquamation of the upper oral mucosa layer, with a shift from mature to more immature cells. These data can be quantitated, and this assay may therefore be useful in studies aimed at prevention of mucositis.

Adult↗
PubMed1997

Conversion of the prodrug etoposide phosphate to etoposide in gastric juice and bile.

Etoposide phosphate is a water-soluble prodrug of etoposide. It was expected that this prodrug could be used to overcome the solubility limitations and erratic bioavailability of oral etoposide. To investigate the possibility of prodrug conversion to etoposide within the gastrointestinal lumen, etoposide phosphate was dissolved in water and incubated with human gastric juice or human bile in vitro. Samples were collected during 150 min and analysed for etoposide concentration with high-performance liquid chromatography. Conversion of prodrug to etoposide during incubation with gastric juice was negligible. There was significant conversion during incubation with bile at pH 7-8. The percentage of prodrug converted to etoposide at pH 8 after 60 min was 78 +/- 18% (mean +/- S.D.) for a 0.1 mg ml-1 prodrug solution and 36 +/- 26% for 0.5 mg ml-1. At pH 7, after 60 min 22% of prodrug was converted to etoposide when incubated at 0.1 mg ml-1 and 10% at 0.5 mg ml-1. No conversion was found after inactivation of alkaline phosphate (AP) by overnight heating of bile at 65 degrees C or by the addition of disodium edetate to the bile. In conclusion, because of AP in bile, variable conversion of etoposide phosphate to etoposide can be expected within the intestinal lumen after oral administration. This could have important pharmacokinetic consequences.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Effects of hemicolectomy on bile acid metabolism in relation to colon carcinogenesis in man.

Bile acids are probably important in colon carcinogenesis. Regional differences in bile acid metabolism within the colon were studied to illuminate the preferential distal occurrence of colon cancer in Western countries. Faeces (24 h) were collected for bile acid measurement from 25 patients with hemicolectomy (nine left and 16 right) and 17 adenoma patients with an intact colon (control subjects). Duodenal bile and cytolytic and alkaline phosphatase activity of faecal water were also studied. The median percentage of deoxycholic acid (DCA) was lower in the hemicolectomy groups [left 48% (range 38-57%), right 45% (2-62%) vs. control subjects 59% (38-70%), P < 0.05]. In duodenal bile, the proportion of DCA in left [4% (1-25%)] was lower than in the patients with right hemicolectomy [19% (0-69%)] and control subjects [24% (7-50%)] P < 0.05. Faecal concentration of protonated DCA was higher in those with right hemicolectomy (0.101 mumol g-1) than in those with left hemicolectomy (0.048 mol g-1), which coincided with a higher cytolytic [right 49% (3-93%), left 2% (1-37%)] and alkaline phosphatase activity [right 6.7 U mL-1 (1.2-40.1 U mL-1), left (2.0 U mL-1 (1-25.7 U mL-1), both P < 0.02]. These findings suggest differences in bile acid metabolism between the proximal and distal colon that may contribute to the disparity in cancer risk.

Adult↗
PubMed1997

Treatment of advanced seminoma: an update.

In this update, the recent developments in the treatment of patients with advanced seminoma are reviewed. Also, the approach for patients with residual disease after chemotherapy is described. It is concluded that the combination of etoposide and cisplatin seems to be the standard treatment for patients with advanced seminoma, showing a durable response in about 90% of the patients. Although the combination of etoposide and carboplatin is less effective, newer carboplatin-based combinations seem to have a comparable efficacy. Residual disease after chemotherapy can be safely observed if the diameter is less than 3 cm; however, residuals larger than 3 cm frequently show a vital tumor and surgical evaluation should therefore be considered.

Antineoplastic Agents↗
PubMed1997

Effects of hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan on pulmonary function assessments.

High doses of tumor necrosis factor-alpha (TNF) seem to be effective in the treatment of solid tumors in the extremities. By applying current intensive care technology, systemic administration of high doses of TNF levels might be feasible for the treatment of cancer in other localizations. To establish the early and late effects of high systemic TNF levels on the lungs, we determined lung function parameters in 12 patients before and after hyperthermic isolated limb perfusion (HILP) with TNF and melphalan. Because of leakage during perfusion, mean maximum systemic TNF levels of 60.0 ng/ml (range, 0.3-356 ng/ml) were obtained. Significant alterations in the vital capacity (VC), the capillary blood volume (Vc), the diffusing capacity of the alveolocapillary membrane (Dm), and the transfer capacity of the lungs for carbon monoxide per unit alveolar volume (KCO) were observed 1 week after HILP. Eight weeks after HILP, they returned to pretreatment value. Alterations in lung functions were not related to the maximum systemic TNF level. In conclusion, disturbances in pulmonary functions are observed in patients after HILP with TNF and melphalan. These disturbances, which are probably partly caused by high systemic TNF levels, are reversible and would not preclude administration of systemic TNF in high doses.

Adult↗
PubMed1997

Fostriecin: a review of the preclinical data.

Fostriecin is a novel antitumor antibiotic. In vitro studies showed that fostriecin inhibits DNA topoisomerase II (Topo II) catalytic activity, protein phosphatases involved with cell-cycle control and histone phosphatases. The relative contribution of these mechanisms to the antitumor activity has not been elucidated, but Topo II inhibition seems to be the major mechanism of action at in vitro cytotoxic fostriecin levels. Tumor cell lines with decreased Topo II content showed similar or increased sensitivity to fostriecin, compared to the parent cell lines. The reduced-folate carrier is probably responsible for the cellular uptake of fostriecin. The possible clinical consequences of these in vitro observations are discussed.

Alkenes↗
PubMed1996

Phase II study of intensive chemotherapy with autologous bone marrow transplantation in patients in complete remission of disseminated breast cancer.

BACKGROUND: This trial studied the disease-free survival after high-dose chemotherapy in patients in complete remission of metastatic breast cancer. PATIENTS AND METHODS: Thirty women, mean age 42.2 years (range 33-55) with metastatic breast cancer, received high-dose chemotherapy in a phase II study. Patients were eligible if they were < or = 55 years of age, had achieved complete remission within 6 months of the initiation of chemotherapy, and had a WHO performance scale of 0 or 1. The high-dose regimen consisted of melphalan 180 mg/m2 and mitoxantrone 60 mg/m2 both divided over 3 days. On day 7 bone marrow and/or peripheral stem cells were infused. After bone marrow recovery, external beam radiation was administered to sites of previous metastatic disease in 15 patients. RESULTS: Apart from leuko- and thrombocytopenia, mucositis was the major side effect. One patient died during the bone marrow transplant period due to an aspergillus infection. The median follow-up since high-dose chemotherapy is 25 months (range 13 to 56 months). The median disease-free survival since high-dose chemotherapy is 27 months and the disease free survival is still 43% with an overall survival of 53% at 3 years. In two patients tumor relapse occurred only in the brain; in one patient the only relapse sign was a meningeal carcinosis. At the moment 17 patients are disease-free (13(+)-56+) months after high-dose chemotherapy. CONCLUSION: Until now this high-dose regimen in selected patients with complete remission after induction chemotherapy for metastatic breast cancer has a promising disease free survival.

Adult↗
PubMed1996

Enhanced effects of bleomycin on pulmonary function disturbances in patients with decreased renal function due to cisplatin.

We examined whether cisplatin-induced nephrotoxicity augmented bleomycin-induced pulmonary toxicity in patients with testicular cancer treated with etoposide and cisplatin with (BEP) or without bleomycin (EP). Before and at 3-week intervals during chemotherapy, creatinine clearance and lung functions were measured. In patients receiving BEP, deterioration of renal function correlated with a decrease in transfer factor of the lungs for carbon monoxide (TLCO) and vital capacity (VC), parameters known to reflect bleomycin-induced pulmonary effects. Other lung functions did not correlate with renal function. In the EP group, no relationships were observed at all. These observations suggest enhanced pulmonary effects of bleomycin when combined with cisplatin. Therefore, attention should be paid to the potential development of bleomycin-induced pulmonary toxicity in patients treated with BEP.

Adolescent↗
PubMed1996

Selection of a subpopulation with fewer DNA topoisomerase II alpha gene copies in a doxorubicin-resistant cell line panel.

A panel of doxorubicin-resistant sublines of the human small-cell lung carcinoma cell line GLC4 displays decreasing DNA topoisomerase II alpha (TopoII alpha) mRNA levels with increasing resistance. In the present study we describe how this decrease may be regulated. No significant differences in TopoII alpha mRNA stability or gene arrangement were found, using mRNA slot-blotting and Southern blotting, in the most resistant cell line compared with the parental cell line. To investigate if TopoII alpha gene copy loss contributed to the mRNA decrease, fluorescence in situ hybridisation using a TopoII alpha-specific probe was performed. During doxorubicin resistance development, the composition of the population in each cell line shifted with increasing resistance, from a population in which most cells contain three TopoII alpha gene copies (GLC4) to a population in which most cells contain only two copies. A partial revertant of the most resistant cell line displayed a shift back to the original situation. We conclude that the TopoII alpha gene copy number decrease per cell line is in good agreement with the decreased TopoII alpha mRNA and protein levels, and TopoII activity levels in these cell lines which were described previously.

Blotting, Southern↗