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T A Splinter

Publications and source records attributed to T A Splinter.

At least 73 records · Page 4Linked to original sources
PubMed1989

Activated ras genes in human seminoma: evidence for tumor heterogeneity.

The incidence of mutations in cellular ras genes was determined in human seminoma, a germ cell tumor of the testis, with the aid of specific oligonucleotide probe hybridization. To eliminate the large number of nonneoplastic cells present in seminomas, aneuploid tumor cell nuclei were isolated from the tumor tissue by flow sorting. Mutations were detected in 40% of the seminomas at codons 12 or 61 of either the Ki-ras or the N-ras gene. No correlation was found with histopathological or clinical features. In some seminomas the mutant gene was present in only a fraction of the tumor cell population, suggesting tumor heterogeneity for ras gene mutations. Yet, flow cytometric measurement of nuclear DNA contents and histological examination of tumor tissue did not reveal two different tumor cell populations. We conclude from these observations that ras mutation is probably not the initial genetic event in the development of seminoma.

Animals↗
PubMed1988

Quantitation of polyamines in cultured cells and tissue homogenates by reversed-phase high-performance liquid chromatography of their benzoyl derivatives.

A rapid and simple method, originally described by Redmond and Tseng [J. Chromatogr., 170 (1979) 479] was applied to the analysis of di- and polyamines in cultured human tumour cells and human tumour xenografts. Optimization of the procedures and evaluation of the characteristic features of the assay are described. The (modified) procedure employs precolumn derivatization with benzoyl chloride, extraction of the derivatives by chloroform, separation by reversed-phase high-performance liquid chromatography under isocratic conditions and detection by ultraviolet absorbance measurement at 229 nm. The complete analysis was accomplished within 10 min per sample. The detection limit was ca. 1 pmol. The intra- and inter-assay coefficients of variation were 2.5-4.4% and 3.4-13.1%, respectively. The presence of well known inhibitors of polyamine biosynthesis, such as DL-alpha-difluoromethylornithine and methylglyoxal bis(guanylhydrazone), did not interfere with the assay, and disturbance by cyclohexylamine could be avoided by changing the polarity of the mobile phase. The method proved to be very suitable because it is rapid, simple, requires a minimum of sample pretreatment, and still provides sufficient sensitivity to quantitate polyamines in relatively small amounts of cells (10(5) cells) or tumour tissues (less than 1 mg), even after treatment with inhibitors of polyamine biosynthesis.

Animals↗
PubMed1988

Levels of neuron-specific enolase after chemotherapy do not predict a response in small cell lung cancer.

Neuron-specific enolase (NSE) was measured in serum samples of 35 patients with small cell lung cancer and 10 control patients. The samples were collected during 10 days after the first course of chemotherapy, in order to investigate whether changes of NSE had a predictive value of tumour response. Three patterns of change of NSE were observed. Pattern 1 showed an increase of serum NSE with a maximum value more than 1.5 times the pretreatment level (n = 17); pattern 2 involved no increase at all or less than 1.5 times the pretreatment level (n = 14); pattern 3 showed a continuous decrease (n = 5). No relationship between the three patterns of change and the tumour response was observed. Only an NSE level less than 10 ng/ml at the time of start of the second course predicted a major response.

Carcinoma, Small Cell↗
PubMed1988

Etoposide and cisplatin in advanced esophageal cancer. A preliminary report.

In order to find an effective and suitable chemotherapy regimen for preoperative treatment of esophageal cancer, patients with inoperable or metastatic disease were treated with a combination of etoposide and cisplatin. Of 27 evaluable patients, 13 had squamous cell carcinoma, 13 adenocarcinoma, and 1 muco-epidermoid carcinoma. No complete responses were noted. Nine of 13 patients with squamous cell carcinoma and only one of 13 with adenocarcinoma showed a partial response. Nine of 10 responders achieved a partial response after 2 courses, one after 4 courses. There was one toxic death, due to sepsis during leukopenia. Other toxicities were alopecia, nausea and vomiting, nephrotoxicity, thrombocytopenia and leukopenia.

Adult↗
PubMed1987

Decarboxylated-S-adenosylmethionine excretion: a biochemical marker of ornithine decarboxylase inhibition by alpha-difluoromethylornithine.

In an attempt to define a biochemical marker of ornithine decarboxylase inhibition in humans, alpha-difluoromethylornithine hydrochloride (DFMO), an irreversible ornithine decarboxylase inhibitor, was infused i.v. in seven cancer patients over 10-day courses at doses of 10-90 g/day and 24-h urinary excretion of polyamines and decarboxylated-S-adenosylmethionine was determined before, during, and after treatment. DFMO produces marked increases in urinary decarboxylated-S-adenosylmethionine excretion, up to 84 times pretreatment values. This response appears to be time dependent, requiring several days to reach a maximum and lasting at least 4-5 days after stopping DFMO. In contrast, urinary excretion of the polyamines putrescine, cadaverine, spermidine, N1-monoacetylspermidine, N8-monoacetylspermidine, and spermine, were not consistently altered by DFMO. We conclude that urinary excretion of decarboxylated-S-adenosylmethionine represents a valid biochemical indicator of ornithine decarboxylase inhibition in humans, whereas urinary polyamines are of no value.

Aged↗
PubMed1987

Problems of pharmacokinetic studies on alpha-difluoromethylornithine in mice.

The pharmacokinetics of alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of polyamine biosynthesis, were investigated in BALB/c (nude) mice after i.p. injection and after oral administration of radiolabeled drug. After i.p. injection the compound was rapidly cleared from the serum (t1/2 alpha = 14 min; t1/2 beta = 2.1 h) and from tissues such as muscle, liver and kidney (t1/2 alpha = 30-60 min; t1/2 beta = 2.1 h). DFMO concentrations were proportional to the administered dose (10-2000 mg/kg) in both serum and tissues. Oral administration of DFMO was carried out by dissolving the compound in drinking water at a concentration of 20 g/l. Studies on the distribution showed that DFMO did not accumulate preferentially in any particular tissue. An extremely wide variation in the dose actually achieved in different animals was observed; this ranged from 350 to 2800 mg/kg for a 14-h treatment period. A significant correlation (r = 0.83-0.92) between the dose of DFMO, calculated from the consumption of drinking water for each individual animal, and the DFMO concentrations in serum, muscle, spleen, liver and kidney was found. Similarly, it was shown that oral administration of DFMO during the daytime resulted in 10- to 15-fold lower levels than administration during the night. After discontinuation of treatment DFMO levels in serum and tissues decreased by 50% in approximately 6 h. From these results it is concluded that the optimal treatment schedule of mice with DFMO (or other drugs with similar pharmacodynamic properties) consists in a combination of oral administration via the drinking water and additional i.p. injection (during the daytime). Furthermore, the drug intake of the individual animals should be monitored to check whether the experimental requirements are actually fulfilled.

Administration, Oral↗
PubMed1987

Neuron-specific enolase as a guide to the treatment of small cell lung cancer.

A retrospective evaluation of serial measurements of neuron-specific enolase (NSE) has been performed in 58 patients with small cell lung cancer (SCLC). All 58 patients received first-line chemotherapy and 11 patients received also second-line treatment after relapse. Samples were obtained every 3-4 weeks during treatment before each cycle of chemotherapy and every 6 or 12 weeks during follow-up. NSE values were depicted on semi-logarithmic paper. Fifty-one times a major response (complete or partial remission) was observed and 49 times the NSE level reached a plateau between 3.5-10 ng/ml. The NSE level did not discriminate between a complete or a partial remission. Seven times stable disease was obtained and the NSE level declined but remained above the normal plateau of 3.5-10 ng/ml. On 50 occasions progressive disease was found. In 3 cases progressive disease was due to a histologically-proven non-small cell lung cancer and NSE levels did not change. In only 5 out of the remaining 47 occasions NSE levels were normal at the time of relapse but rose later in 4. On 42 occasions of progressive SCLC an exponential rise of NSE was found, often within the range of 3.5-20 ng/ml. None of 6 patients, who are still incomplete remission for 1-5 years, showed a consistent rise of NSE. Serial measurements of serum NSE, can predict the occurrence of a major response, stable disease and progressive disease outside the brain with a very high accuracy and seem to be at least a useful addition to standard investigational methods to guide the treatment of SCLC.

Adult↗
PubMed1987

Retreatment with the induction regimen in small cell lung cancer relapsing after an initial response to short term chemotherapy.

In 37 patients with small cell lung cancer treatment with five cycles of cyclophosphamide, doxorubicin and etoposide (CDE), resulted in 23 complete (CR) and 14 partial responses (PR). Median response duration was 34 weeks. At relapse all patients were retreated with CDE. In 23 (62%) patients this gave a second response (6 CR, 17 PR). Factors influencing the occurrence of a second response were: 1. a CR after the first five cycles of CDE; 18 out of 23 CR patients responded again whereas only five of the 14 PR patients responded (P less than 0.01). 2. 15 out of 19 patients with a first response duration greater than 34 weeks reached a second response and in eight of the other 18 patients retreatment was successful (P less than 0.05). Reinduction at relapse, after short term chemotherapy and a treatment-free interval, with the induction regimen is an effective second line treatment in patients with an initial CR and a first response duration of greater than 34 weeks.

Adult↗
PubMed1987

Combination chemotherapy with cisplatin and methotrexate in advanced transitional cell cancer of the bladder.

We studied 53 patients with bidimensionally measurable metastases of transitional cell cancer of the bladder who were treated with a planned regimen of 70 mg. per m. cisplatin intravenously on day 1, and 40 mg. per m. methotrexate intravenously on days 8 and 15 every 3 weeks. The toxicity of this regimen, with agranulocytosis and mucositis as the most important side effects, was so severe that only 17 per cent of the patients actually received the protocol regimen without modification. Six patients were ineligible and 47 were evaluable for toxicity, including 43 who were evaluable for response. The response to treatment was assessed after each second treatment cycle. A complete response was achieved in 10 patients (23 per cent) and a partial response was achieved in 10 (23 per cent). The median duration of response was 64 weeks for patients with a complete response and 23 weeks for those with a partial response, while the median duration of survival was 81 and 37 weeks, respectively. The aforementioned regimen with allowance of routine leucovorin rescue is tested as preoperative chemotherapy in patients with stages T3 to T4 nonmetastatic bladder cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Doubling time of neuron-specific enolase and survival in small cell lung cancer patients. Results of a preliminary analysis.

During a retrospective analysis of the value of neuron specific enolase (NSE) in patients with small cell lung cancer (SCLC) it became apparent that at progressive disease (PD) NSE rose exponentially with a doubling time (NSE-Td) varying from 10 - 94 days. In this study the influence of the NSE-Td on the survival of 29 SCLC-patients has been investigated. A significant correlation between survival from the start of rise of NSE at PD and NSE-Td was observed. By extrapolating the exponential rise of NSE to the start of treatment a theoretical logarithmic value of NSE, called Yr, could be calculated. When the patients were grouped according to the Yr value greater than -1, between -1 and -4 and less than or equal to -4 a highly significant correlation between the survival from the start of treatment and NSE-Td was found in all 3 groups. These preliminary data suggest that by means of NSE-Td and Yr value the survival of an SCLC-patient from the time of rise of NSE and from the start of treatment may be predicted within certain limits.

Carcinoma, Small Cell↗
PubMed1986

Species-dependent differences of the biochemical properties of diamine oxidase.

Diamine oxidase (DAO) from tissues of mice, rats and humans showed different properties with respect to stability and kinetic parameters. DAO-activities in homogenates of rat or human tissues, but not of mouse tissues, rapidly decreased upon storage at -20 degrees C. The Km-value for putrescine was 90 microM in mouse kidney or intestine. In rats different Km-values were observed before (272 microM) and after freezing (102 microM). A similar effect was observed with DAO in human kidney (321 and 39 microM, respectively). Treatment of rats with heparin resulted in a depletion of intestinal DAO and the concomitant appearance of DAO in blood. The enzyme remaining in the intestine showed the lower Km-value.

Amine Oxidase (Copper-Containing)↗
PubMed1986

Phase I study of alpha-difluoromethylornithine and methyl-GAG.

alpha-Difluoromethylornithine (DFMO) is a potent inhibitor of the synthesis of putrescine (pu) and spermidine (sd) in some benign and malignant tissues. Intracellular deprivation of pu and sd has been shown to induce an enhanced uptake of polyamine-analogs such as methyl-GAG (MGBG). The purpose of this study was to investigate the tolerance and the toxicity of the combination of DFMO and MGBG. Thirty-six patients received 4 X 2 g of DFMO/day orally and every 2 weeks 250-500 mg/m2 of MGBG as a 2-hr infusion, starting on day 14. Besides the well known acute and late side-effects of methyl-GAG, dose-limiting toxicity consisted also of thrombocytopenia, leucopenia, dyspnea, hemolysis and jaundice. The maximal tolerated dose of MGBG for one course was 350 mg/m2 and for repeated courses 250 mg/m2, due to cumulative toxicity. Furthermore, after 8 weeks of continuous administration of DFMO 70% of the patients had a severe hearing loss, which was reversible after a treatment delay of 4-6 weeks. Since the hearing loss prohibited the continuous use of DFMO, two different schedules of intermittent DFMO-administration together with two different infusion periods of MGBG have been investigated in 15 patients. In none of these patients did hearing loss occur. The schedule of continuous administration of 4 X 2 g of DFMO/day orally for 21 days and 250 mg/m2 of MGBG as a 24-hr infusion on days 7, 14 and 21, repeated on day 42, was tolerated best. In 28 evaluable patients two partial remissions were seen. Pretreatment with DFMO significantly enhanced the toxicity of MGBG and the combination of both drugs produced side-effects not seen with either drug alone.

Adolescent↗