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1.
Artigo em Inglês | MEDLINE | ID: mdl-17100219

RESUMO

PURPOSE: Business process redesign (BPR) is used to implement organizational transformations towards more customer-focused and cost-effective care. Ideally, these innovations should be carefully described and evaluated so that "best practices" can be re-applied. To investigate this, available evidence was collected on patient care redesign projects. DESIGN/METHODOLOGY/APPROACH: The Ebsco Business Source Premier, Embase and Medline databases were searched. Studies on innovations related to re-engineering patient care that used before-after design as minimum prerequisites were selected. General characteristics, logistic parameters and other outcome measures to determine the objectives and results and interventions used were looked at. FINDINGS: A total of 86 studies that conformed to the criteria were found: a minority mentioned measurable parameters in their objectives. In the majority of studies, multiple interventions were combined within single studies, making it impossible to compare the effects of individual interventions. Only three randomized controlled trials were found. Furthermore, inconsistencies were noted between the study objectives and the reported results. Many more issues were reported in the results than were mentioned in the study aims. It would appear that publications were hard to find owing to a lack of specific MeSH headings. Nearly 7,500 abstracts were scanned and from these it was concluded that clear and univocal research methods, terms and reporting guidelines are advisable and must be developed in order to learn and benefit from BPR innovations in health care organizations. ORIGINALITY/VALUE: This appears to be the first time available evidence about redesign projects in hospitals has been systematically collected and assessed.


Assuntos
Medicina Baseada em Evidências , Administração Hospitalar , Assistência Centrada no Paciente , Programas Nacionais de Saúde , Países Baixos , Inovação Organizacional
2.
Int J Hyperthermia ; 15(6): 549-56, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10598951

RESUMO

PURPOSE: To investigate the schedule-dependency of 2',2'difluorodeoxycytidine (dFdC, Gemcitabine) combined with hyperthermia (HT), in vitro as well as in vivo. MATERIALS AND METHODS: Rat R-1 rhabdomyosarcoma cells were treated with various concentrations of dFdC for 70 min, 4 h and 24 h. After various time intervals HT (60 min at 43 degrees C) was applied. Cell survival was determined by clonogenic assays. Female Wag/Rij rats bearing R-1 tumours on the hind limbs were treated with dFdC (20 mg/kg), with locally applied HT (60 min at 43 degrees C) or with a combined treatment using different time intervals (0, 24 and 48 h). Tumour growth delay (TGD) and normal tissue toxicity were assessed. RESULTS: With dFdC alone, significant cytotoxicity was observed after a 24 h-exposure. Except for the 24 h-exposure, HT reduced the cytotoxicity of dFdC in simultaneous applications. An enhanced cytotoxic effect was found when HT was applied 20 h after a 4 h-incubation with dFdC. In vivo, HT applied 48 h after dFdC-administration resulted in potentiation of the effect of dFdC with respect to TGD without an increase in toxicity. CONCLUSIONS: The efficacy of dFdC combined with HT is schedule-dependent both in vitro and in vivo. The addition of HT enhances the effectiveness of dFdC in the R-1 tumour model.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Desoxicitidina/análogos & derivados , Hipertermia Induzida , Rabdomiossarcoma/terapia , Animais , Divisão Celular , Sobrevivência Celular , Terapia Combinada , Desoxicitidina/efeitos adversos , Desoxicitidina/uso terapêutico , Feminino , Hipertermia Induzida/efeitos adversos , Ratos , Rabdomiossarcoma/tratamento farmacológico , Rabdomiossarcoma/patologia , Gencitabina
3.
J Cancer Res Clin Oncol ; 125(10): 549-55, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10473867

RESUMO

Cell-cycle checkpoints are thought to govern the cellular response to external stimuli. The involvement of the p53 tumour-suppressor protein and the retinoblastoma protein (pRb) in the cell-cycle checkpoint in G1 phase is well established. However, little is known about the importance of these G1 checkpoint regulators in hyperthermia-induced cytotoxicity. Such information is relevant because of the clinical application of hyperthermia in combination with chemotherapy or with radiotherapy. The effects of p53 or pRb inactivation were studied in a well-established isogenic system using the human colorectal carcinoma cell line (RKO). The cells were treated with clinically relevant heat doses (60 min at 40-43 degrees C). Cell survival, cell-cycle redistribution and induction of apoptosis were investigated. Survival of the p53-inactivated transfectants was higher than that of the wild-type p53 cells. The pRb-inactivated transfectants showed an intermediate sensitivity to hyperthermia. All transfectants showed G2 arrest after hyperthermia and the appearance of a sub-G1 population. The induction of apoptosis was inhibited in p53-inactivated and pRb-inactivated transfectants. These results suggest that p53 and/or pRb status may be an important determinant of the clinical response to hyperthermia.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apoptose , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/terapia , Regulação Neoplásica da Expressão Gênica , Hipertermia Induzida , Proteína do Retinoblastoma/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ciclo Celular , Sobrevivência Celular , Humanos , Radioterapia/métodos , Fatores de Tempo , Células Tumorais Cultivadas
4.
Eur J Cancer ; 34(10): 1592-7, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9893634

RESUMO

The occurrence of neuro-endocrine deficiencies following craniospinal irradiation for medulloblastoma is well known, but data concerning the spectrum and prevalence of endocrine abnormalities in adulthood are scarce. We studied endocrine function in 20 (median age 25 years) adult subjects, 8-25 years (median 16 years) after therapy. The radiation dose to the whole cranium and spinal axis was 35 +/- 2.6 Gray (mean +/- standard deviation) with a boost to the posterior fossa of 18 +/- 3.7 Gray. 13 subjects had received additional chemotherapy. In 15 of 20 (75%) subjects, endocrine abnormalities were observed. In 14 (70%), growth hormone (GH) secretion was impaired; 7 (35%) subjects had an absolute GH deficiency, while 7 (35%) showed subnormal responses to insulin-induced hypoglycaemia. In contrast, only 20% (4) of these subjects showed impairment of the hypothalamus-pituitary-thyroid (HPT) axis, while 15% (3) showed central impairment of hypothalamus-pituitary-gonadal (HPG) function. Central impairment of the HPG axis was associated with impaired GH secretion in all cases. Central adrenal insufficiency was not observed. Basal levels of prolactin were normal in all subjects. Young age at treatment was a determinant of GH deficiency in adulthood (P = 0.014). Neither post-treatment interval, nor the use of chemotherapy were determinants of central endocrine impairment in adulthood. In long-term survivors of medulloblastoma, GH deficiency has a high prevalence. In contrast, impairment of the HPG and HPT axis is less common, while central adrenal insufficiency was not observed.


Assuntos
Neoplasias Cerebelares/radioterapia , Irradiação Craniana/efeitos adversos , Doenças do Sistema Endócrino/etiologia , Meduloblastoma/radioterapia , Adolescente , Adulto , Neoplasias Cerebelares/complicações , Criança , Pré-Escolar , Feminino , Seguimentos , Hormônio do Crescimento/metabolismo , Humanos , Hipotálamo/metabolismo , Masculino , Meduloblastoma/complicações , Hipófise/metabolismo , Sobreviventes , Glândula Tireoide/metabolismo , Fatores de Tempo
5.
Int J Radiat Oncol Biol Phys ; 39(2): 489-96, 1997 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9308955

RESUMO

PURPOSE: To investigate the possible benefit of hyperthermia (HT) in combination with radiosensitization by halogenated pyrimidines (HPs) in rodent as well as in human tumor cells. METHODS AND MATERIALS: Exponentially growing rodent cells, radiosensitive R-1 and MOS cells and radioresistant RUC-II and V79 cells, and human SW1573 cells, were exposed to 0, 1, 2, and 4 microM of chloro- (CldUrd), bromo- (BrdUrd), or iodo-deoxyuridine (IdUrd) in the culture medium. Survival after irradiation with gamma-rays from a 137Cs source and/or hyperthermic treatment (HT, 60 min at 42 degrees C) was determined by clonogenic assay. Linear-quadratic analyses of the radiation survival curves were performed to assess sensitization in the dose range 1 to 3 Gy relevant to radiotherapy. RESULTS: The incorporation of HPs sensitized all cell lines to HT and resulted in radiosensitization dependent on the percentage of thymidine replacement. At equal levels of thymidine replacement, IdUrd was the most potent radiosensitizer. HT further increased radiation-induced lethality of cells that had incorporated HPs. Linear-quadratic analyses showed that HT further increased the linear parameter of the LQ formula while the quadratic parameter was not significantly changed. CONCLUSION: The combination of HT and HPs act additively in increasing the radiosensitivity of rodent tumor cell lines with varying radiosensitivities as well as of a human tumor cell line. In particular, the ratio of the linear parameter to the quadratic parameter, relevant for fractionation effects in radiotherapy, was increased.


Assuntos
Desoxiuridina/análogos & derivados , Desoxiuridina/farmacocinética , Hipertermia Induzida , Radiossensibilizantes/farmacocinética , Animais , Bromodesoxiuridina/farmacocinética , Sobrevivência Celular/efeitos da radiação , Terapia Combinada , Cricetinae , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Idoxuridina/farmacocinética , Ratos , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/efeitos da radiação
6.
Cancer ; 79(5): 935-43, 1997 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-9041156

RESUMO

BACKGROUND: The biologic rationale for combining cisplatin with locoregional hyperthermia (HT) relates to the potentiating effect of HT on cisplatin cytotoxicity. METHODS: Patients with recurrent cervical carcinoma, who had a pelvic recurrence after radiotherapy, were treated with weekly cycles of locoregional HT (using the 70-megahertz, 4 antenna-phased array system for 1 hour and cisplatin, 50 mg/m2 intravenously [i.v.], for a maximum of 12 cycles.) RESULTS: Twenty-three patients were entered in this study. A total of 169 cycles were given. Responses were observed in 12 of 23 patients, a response rate of 52% (95% confidence interval, 31-73%). Salvage surgery became possible in 3 of 12 responding patients, whose tumors were previously considered unresectable. The median duration of response was 9.5+ months, the median overall survival was 8+ months, and the 1-year survival was 42%. No correlation was found between treatment outcome and clinical parameters such as age, weight, performance status, and histology. Thermal parameters such as T20, T50, and T90 were higher in responding patients, but were not significantly different from nonresponding patients. Overall toxicity was moderate. Subcutaneous fatty necrosis due to HT occurred in 10% of the cycles, whereas 2 patients developed skin burns. Squamous cell carcinoma antigen proved to be a valuable tool for the evaluation of response and detection of progression. CONCLUSIONS: Weekly locoregional HT and cisplatin, 50 mg/ m2 i.v., for a maximum of 12 cycles was effective treatment in patients with a previously irradiated recurrent carcinoma of the uterine cervix.


Assuntos
Carcinoma de Células Escamosas/terapia , Cisplatino/uso terapêutico , Hipertermia Induzida , Serpinas , Neoplasias do Colo do Útero/terapia , Antígenos de Neoplasias/análise , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/imunologia , Cisplatino/efeitos adversos , Esquema de Medicação , Feminino , Humanos , Hipertermia Induzida/efeitos adversos , Recidiva Local de Neoplasia , Análise de Sobrevida , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/imunologia
7.
J Cancer Res Clin Oncol ; 123(1): 6-12, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-8996534

RESUMO

The cytotoxicity of cisplatin and cisplatin-DNA adduct formation in vitro and in vivo is clearly enhanced by hyperthermia. We investigated whether cytotoxicity and platinum-DNA adduct formation of two promising new third-generation platinum derivatives, lobaplatin [1,2-diamminomethylcyclobutane platinum(II) lactate] and oxaliplatin [oxalato-1,2-diaminocyclohexane platinum(II)], are also enhanced by hyperthermia. Cisplatin was used for comparison. SW 1573 cells were incubated with cisplatin, lobaplatin or oxaliplatin at different concentrations for 1 h at 37 degrees, 41 degrees and 43 degrees C. The reproductive capacity of cells was determined by cloning experiments. Immunocytochemical detection of platinum-DNA adducts was performed with the rabbit antiserum NKI-A59. At 37 degrees C, cisplatin was the most cytotoxic, followed by oxaliplatin and lobaplatin. Hyperthermia clearly enhanced the cytotoxicity of cisplatin, lobaplatin and oxaliplatin. There was no further increase in cytotoxicity at 43 degrees C compared to 41 degrees C for cisplatin and oxaliplatin. A further increase in cytotoxicity at 43 degrees C was observed for lobaplatin. At 43 degrees C thermal enhancement was higher for lobaplatin than for oxaliplatin, with the reverse pattern at 41 degrees C. For both drugs, thermal enhancement of cytotoxicity was lower than observed for cisplatin. Immunocytochemical detection of platinum-DNA adducts was feasible for all the drugs. Adduct formation was enhanced at 43 degrees C for cisplatin, lobaplatin and oxaliplatin with a relative increase of 410%, 170% and 180%. These results seem to confirm that an increase in platinum-DNA adduct formation is involved in the in vitro thermal enhancement of cytotoxicity. The observed thermal enhancement of cytotoxicity of lobaplatin and oxaliplatin in vitro warrants further in vivo investigations.


Assuntos
Adutos de DNA/metabolismo , DNA de Neoplasias/metabolismo , Hipertermia Induzida , Compostos Organoplatínicos/metabolismo , Compostos Organoplatínicos/farmacologia , Platina/metabolismo , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Cisplatino/metabolismo , Cisplatino/farmacologia , Ciclobutanos/metabolismo , Ciclobutanos/farmacologia , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Oxaliplatina , Células Tumorais Cultivadas
8.
Int J Radiat Oncol Biol Phys ; 36(1): 135-40, 1996 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-8823268

RESUMO

PURPOSE: We have investigated differences in the efficacy of combined treatment with cis-diamminedichloroplatinum(II) (cDDP) and local hyperthermia (HT) in nonirradiated and preirradiated experimental tumors. METHODS AND MATERIALS: Survival of R-1 rhabdomyosarcoma cells was assessed after treatment with various cDDP-concentrations at 37 degrees C and 42 degrees C in vitro. Rats bearing R-1 rhabdomyosarcomas of 190 mm3 (SE 15 mm3) were treated with cDDP (6 mg/kg i.p.), HT (1 h at 43 degrees C), or cDDP+HT (45 min interval) without preirradiation or at day 16 after the first dose of fractionated irradiation. Fractionated irradiation consisted of four daily doses of 5 Gy of x-rays each and tumor volumes had regrown to their original volume at the time of treatment. Experimental endpoint was tumor growth delay (TGD). RESULTS: Hyperthermia-enhanced cDDP cytotoxicity in vitro by a factor of about 5. Treatment with cDDP or HT alone resulted in a similar TGD in non- and preirradiated tumors (7.2 vs. 7.4 days and 1.1 vs. 0.9 days, respectively). In non- as well as in preirradiated tumors, HT given in combination with cDDP significantly enhanced the effect of cDDP, prolonging the TGD (11.1 days (p = 0.0001) and 16.2 days (p < 0.0001), respectively) corresponding to a TGD-enhancement of 1.54 and 2.19, respectively. The TGD after cDDP+HT in preirradiated tumors was significantly longer than in nonirradiated tumors (p = 0.0003). CONCLUSIONS: In this tumor model, HT enhanced the antitumor effect of cDDP. Previous radiation treatment did not reduce the HT-enhanced effect of cDDP. Combined cDDP and HT may be useful in the treatment of nonirradiated tumors as well as previously irradiated tumors.


Assuntos
Cisplatino/administração & dosagem , Hipertermia Induzida , Neoplasias Experimentais/terapia , Animais , Terapia Combinada , Relação Dose-Resposta a Droga , Feminino , Ratos , Recidiva , Rabdomiossarcoma , Fatores de Tempo , Células Tumorais Cultivadas
9.
Int J Hyperthermia ; 12(2): 241-54, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8926392

RESUMO

The influence of local hyperthermia (HT) on Mitoxantrone (MITOX) effectiveness was studied in an experimental rat tumour. R-1 rhabdomyosarcomas were treated with MITOX (5 mg/kg ip), HT (43 degrees C for 1 h) or combinations applied at various time intervals up to 24 h. Tumour growth delay and tumour cell clonogenicity were assessed in correlation with the pharmacokinetics in blood plasma and with MITOX-concentrations in tumour tissue. Combined treatments were more effective than expected on the basis of simple addition of effects of single treatments. With increasing time intervals between treatments up to 8 h, an increase in effectiveness was observed. Unfortunately, treatment with an 8-h interval resulted in a high mortality: 80% of the rats died with 5-10 days after treatment. Treatment with a 3-h interval between MITOX and HT was the most effective combination resulting in the highest therapeutic ratio. Even local tumour controls (14/18 rats) were observed. These enhanced effects were associated with a higher MITOX-concentration in the fraction of intact cells recovered from tumours. However, no differences were observed in MITOX-concentration in total tumour tissue nor in plasma concentrations. In conclusion, timing between MITOX and HT is important for drug availability, for interaction of the two modalities to increase damage in tumour cells and for limiting the toxicity to normal tissues.


Assuntos
Antineoplásicos/uso terapêutico , Hipertermia Induzida , Mitoxantrona/uso terapêutico , Rabdomiossarcoma/tratamento farmacológico , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/toxicidade , Divisão Celular/efeitos dos fármacos , Células Clonais , Terapia Combinada , Feminino , Mitoxantrona/farmacocinética , Mitoxantrona/toxicidade , Ratos , Rabdomiossarcoma/patologia , Células Tumorais Cultivadas
10.
Int J Radiat Oncol Biol Phys ; 34(4): 887-93, 1996 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-8598366

RESUMO

PURPOSE: The biological rationale for combining locoregional hyperthermia (HT) with cisplatin (CDDP) is the potentiating effect of HT on CDDP uptake and cytotoxicity. Feasibility, toxicity, and preliminary results of a clinical trial of weekly loco-regional HT in combination with cisplatin are described in this article. METHODS AND MATERIALS: Patients with previously irradiated unresectable local recurrent cervical carcinoma or locally advanced bladder carcinoma were treated with weekly cycles of locoregional HT (70 MHz four antenna phased array system) for 1 h and CDDP 50 mg/m(2) IV for a maximum of 12 courses. RESULTS: Fourteen patients, 10 patients with recurrent cervical carcinoma and 4 with locally advanced bladder carcinoma, were entered in this study. A total of 100 cycles were given. Overall toxicity was acceptable; Grade 3 (WHO) toxicity (gastrointestinal, hematological, and neurotoxicity) was observed in 5 out of 14 patients. No Grade 4 toxicity was seen. Subcutaneously fatty necrosis due to HT occurred in 11% of the cycles, while two patients developed skin burns. Two out of 10 patients with recurrent cervical carcinoma were not evaluable for response. Four out of eight evaluable cervical carcinoma patients responded (two pathologic complete responses, one pathologic confirmed partial response, one partial response): response rate 50% (95% confidence interval 15.7-84.3%). Salvage surgery became possible in three out of four responding patients, whose tumors were previously considered unresectable. Two out of the four evaluable patients with locally advanced bladder carcinoma responded (two partial responses). CONCLUSIONS: Weekly loco-regional HT and CDDP 50 mg/m(2)/week for a maximum of 12 courses is feasible with an acceptable toxicity, which seems not to be enhanced by the addition of loco-regional HT. The encouraging preliminary results of this treatment schedule warrant further study, especially in patients with previously irradiated recurrent cervical carcinomas.


Assuntos
Antineoplásicos/administração & dosagem , Carcinoma de Células de Transição/terapia , Cisplatino/administração & dosagem , Hipertermia Induzida , Recidiva Local de Neoplasia/terapia , Neoplasias da Bexiga Urinária/terapia , Neoplasias do Colo do Útero/terapia , Adulto , Idoso , Antineoplásicos/efeitos adversos , Carcinoma de Células de Transição/patologia , Carcinoma de Células de Transição/radioterapia , Cisplatino/efeitos adversos , Terapia Combinada , Esquema de Medicação , Estudos de Viabilidade , Feminino , Audição/efeitos dos fármacos , Humanos , Hipertermia Induzida/efeitos adversos , Rim/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Indução de Remissão , Fatores de Tempo , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/radioterapia , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/radioterapia
11.
Cancer Res ; 56(3): 563-8, 1996 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8564972

RESUMO

The combination of local hyperthermia (HT) with thermostable liposomal daunorubicin (DaunoXome, DX) was investigated to assess targeted drug delivery to experimental tumors. Female Wag/Rij rats bearing solid R-1 rhabdomyosarcomas received i.v. injections of 10 or 15 mg/kg of DX or free-Daunorubicin (f-Dau). After a 1-h interval, HT (60 min at 43 degrees C) was applied. Pharmacokinetics were studied in relation to tumor growth time (TGT), i.e., the time for tumors to reach their original volumes. Pharmacokinetic studies revealed that DX accumulation in tumor tissue was similar to f-Dau. A 5.4-fold increase (P = 0.0084) in tumor drug delivery was observed when DX was combined with HT, whereas liposomes remained stable. For f-Dau, HT had an additional effect on TGT at both drug doses tested (9.6 and 6.2 days, respectively, for 10 mg/kg, P = 0.0092; 17.7 and 13.7, respectively, for 15 mg/kg, P = 0.0431). For DX, HT significantly enhanced TGT of DX in the lower dose (17.1 and 6.4 days, respectively, P = 0.0005), whereas tumors did not regrow at day 25 after DX + HT in the higher dose. Unfortunately, after this time interval, the animals died of late toxicity, probably not related to HT. These results indicate that HT promotes extravasation of DX into tumor tissue and enhances its effectiveness. The finding that HT-induced drug release from the liposomes was not responsible for enhanced antitumor activity provides a rationale for further investigation of thermostable liposomes in conjunction with HT.


Assuntos
Daunorrubicina/farmacologia , Daunorrubicina/farmacocinética , Hipertermia Induzida , Rabdomiossarcoma/metabolismo , Rabdomiossarcoma/terapia , Animais , Divisão Celular/efeitos dos fármacos , Terapia Combinada , Daunorrubicina/administração & dosagem , Portadores de Fármacos , Feminino , Lipossomos , Ratos , Ratos Endogâmicos , Rabdomiossarcoma/tratamento farmacológico
12.
J Cancer Res Clin Oncol ; 122(3): 147-53, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8601562

RESUMO

Tumours regrowing after irradiation may respond differently to chemo-hyperthermia as compared to non- irradiated tumours. In this study, the efficacy of combined treatment of previously irradiated tumors with mitoxantrone and local hyperthermia (HT) was investigated. Rat R-1 tumours were irradiated with dose fractions of 5Gy X-rays applied on 4 consecutive days. Animals were retreated with mitoxantrone (5mg/kg i.p.), HT (1 h at 43 degrees C) or mitoxantrone + HT (3-h interval) on day 9 after the start of irradiation when tumour volumes were decreasing, or on day 16 when tumour volumes were increasing again. Pharmacokinetics were studied in relation to tumor cell survival and tumour growth delay. No Ht=induced changes in the pharmacokinetics of mitoxantrone were observed. The data on clonogenic survival correlated well with these findings and combined treatment were not more effective than mitoxantrone alone. In the treatment schedule applied, HT did not induce pharmacokinetic changes in irradiated tumours leading to an enhanced cytotoxicity of mitoxantrone. The HT- enhanced effectiveness of the drug observed in non- irradiated tumours is much less in pre-irradiated tumours. Responses of regrowing tumours to combined chemo- hyperthermia depend in a complex way on the stage of regrowth and on the treatment schedule.


Assuntos
Antineoplásicos/farmacologia , Hipertermia Induzida , Mitoxantrona/farmacologia , Recidiva Local de Neoplasia/terapia , Rabdomiossarcoma/terapia , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/toxicidade , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Terapia Combinada , Feminino , Mitoxantrona/farmacocinética , Mitoxantrona/toxicidade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/metabolismo , Ratos , Ratos Endogâmicos , Rabdomiossarcoma/metabolismo , Rabdomiossarcoma/radioterapia
13.
Int J Cancer ; 62(5): 627-30, 1995 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-7665236

RESUMO

Difluorodeoxycytidine (dFdCyd, gemcitabine) was tested for cytotoxicity in cultured human lung-cancer cells SW1573 in combination with 1 hr hyperthermia at 43 degrees C. The results show that the timing is extremely important. Simultaneous application led to decreased cytotoxicity, whereas an interval of 20 or 24 hr between exposure to dFdCyd and hyperthermia led to enhanced cell killing. The decrease in cytotoxicity after simultaneous hyperthermia and dFdCyd probably results from inhibition of activation of dFdCyd to the triphosphate metabolite. The enhanced cytotoxicity in sequential application of dFdCyd and hyperthermia is not caused by accumulation of cells in a sensitive cell-cycle phase. Our results show that the G1 phase becomes relatively abundant 20 hr after exposure to 0.1 microM dFdCyd, approximately 48% versus 31% in control cultures. Presumably, inhibition by hyperthermia of repair of DNA damage plays a role. Our results confirm earlier data with regard to reutilization of activated dFdCyd at high cell density. dFdCyd was clearly more toxic to SW1573 cells at 4 x 10(5) cells per dish than at 400 cells per dish. This reutilization of activated drug is evidently not a restricted property of a particular cell line and may add to the value of the drug in cancer treatment.


Assuntos
Desoxicitidina/análogos & derivados , Hipertermia Induzida , Células Tumorais Cultivadas/efeitos dos fármacos , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Sobrevivência Celular/efeitos dos fármacos , Desoxicitidina/administração & dosagem , Humanos , Técnicas In Vitro , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Gencitabina
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