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Biomedical subjects

J Wierzbicki

Publications and source records attributed to J Wierzbicki.

At least 19 recordsLinked to original sources
PubMed2000

[Esophageal substitute corrective operations].

In the Clinic of Gastrointestinal Surgery at the Medical University in Wrocław in 402 cases substernal oesophageal reconstruction was performed using different pedunculated oesophageal substitutes. 63 patients had to be operated on for the second time because of disorders in the oesophageal substitute. In 13 cases stenosis in the upper anastomosis and in 3 patients stenosis in the anastomosis with stomach were corrected. In 7 cases oesophageal ulcer was excised. 6 patients were operated because of substitute herniation into pleural cavity. In 3 cases huge diverticula in the neck were removed. 5 patients were operated because of stomach outlet stenosis. In 15 cases operation was necessary to correct the sequel of reflux oesophagitis. In 8 cases the surgery was performed to remove stenosis of the substitute. In 2 cases there was torsion of substitute and in the other 2 cases postoperative stenosis was caused by adhesions. One patient was operated because of the dumping syndrome. In 2 patients with the colon substitute polyps from the segment used for the oesophagus were removed endoscopically. The mortality after corrective surgery on the oesophageal substitute was less than 10% (6/63).

Anastomosis, Surgical↗
PubMed1999

[Postop complication of pancreatic resection].

Early complications after partial pancreatic resections and benign pancreatic tumours were analysed. 276 patients with pancreatic tumours were treated in the years 1979-1997. In 77 cases radical operation was performed. 65 patients underwent Whipple and 12--Traverso-Longmire pancreatoduodenectomy. Malignant tumour was found in 55 cases and 22 were benign. In 4 patients tumour's resection along with invaded portal vessels and portal confluence reconstruction was performed. These were the first cases with vessels resection operated in Poland. There were 2 post-operative deaths observed in that group. Complications in our material were as follows: pancreatico-jejunal anastomosis fistulae, haemorrhage from ulcers in gastro-jejunal anastomosis, diffuse peritonitis, haemorrhage from pancreatic stump vessels, ileus, acute renal insufficiency, pneumonia and myocardial infarct. Mortality in whole group was 11%. In the last 5 years due to our growing experience and some technical modifications mortality fell to 4.4%.

Female↗
PubMed1997

[Intraoperative portography in operations for resection of pancreas neoplasms].

Since 1993 during pancreatic resection routine intraoperative portography has been employed. Thus we are able to establish infiltration engaging portal vein and its branches. Facilitating decision making about resectability of the tumor. 29 portographies were performed. In eight cases malignant infiltration on portal vein was established. Because of that in seven cases no radical resection was undertaken.

Aged↗
PubMed1997

[Tumor in Vater's ampulla--local excision or Whipple's resection].

Results of the operative treatment of Vater's papilla carcinoma in fifteen cases were analysed. Eleven patients had pancreatoduodenectomy according to Whipple, four had only local excision of Vater's papilla along with the tumour. All four had early recurrence and were re-operated by Whipple method. In our experience only radical pancreatoduodenectomy with regional lymphadenectomy, preferably Whipple type, gives chance of achieving the radical cure.

Adenocarcinoma↗
PubMed1997

[Endoscopic bouginage of benign esophageal and cardial strictures].

Endoscopic bouginage of benign esophageal and cardial strictures was compared with surgical treatment. Bouginage was performed by Celestin or Eder-Puestow bougies. Results obtained suggest usefulness of bouginage in many patients with benign stenosis of the upper gastrointestinal tract.

Adult↗
PubMed1994

A feasibility study of 252Cf neutron brachytherapy, cisplatin + 5-FU chemo-adjuvant and accelerated hyperfractionated radiotherapy for advanced cervical cancer.

PURPOSE: To evaluate the feasibility and toxicity of 252Cf neutron brachytherapy combined with hyperaccelerated chemoradiotherapy for Stage III and IV cervical cancers. METHODS AND MATERIALS: Eleven patients with advanced Stage IIIB-IVA cervical cancers were treated with 252Cf neutron brachytherapy in an up-front schedule followed by cisplatin (CDDP; 50 mg/m2) chemotherapy and hyperfractionated accelerated (1.2 Gy bid) radiotherapy given concurrently with intravenous infusion of 5-Fluorouracil (5-FU) (1000 mg/m2/day x 4 days) in weeks 1 and 4 with conventional radiation (weeks 2, 3, 5, and 6). Total dose at a paracervical point A isodose surface was 80-85 Gy-eq by external and intracavitary therapy and 60 Gy at the pelvic sidewalls. RESULTS: Patients tolerated the protocol well. There was 91% compliance with the chemotherapy and full compliance with the 252Cf brachytherapy and the external beam radiotherapy. There were no problems with acute chemo or radiation toxicity. One patient developed a rectovaginal fistula (Grade 3-4 RTOG criteria) but no other patients developed significant late cystitis, proctitis or enteritis. There was complete response (CR) observed in all cases. With mean follow-up to 26 months, local control has been achieved with 90% actuarial 3-year survival with no evidence of disease (NED). CONCLUSION: 252Cf neutrons can be combined with cisplatin and 5-FU infusion chemotherapy plus hyperaccelerated chemoradiotherapy without unusual side effects or toxicity and with a high local response and tumor control rate. Further study of 252Cf neutron-chemoradiotherapy for advanced and bulky cervical cancer are indicated. We found chemotherapy was more effective with the improved local tumor control.

Adult↗
PubMed1994

New understanding from Cf brachytherapy trials and considerations for neutron therapy of bulky gyn carcinoma for future.

PURPOSE: This study reviews the radiobiology of neutrons and the results and methods that have evolved in the Cf-252 neutron brachytherapy trials to postulate methods to explore for their potential applicability to fast neutron beam therapy. METHODS AND MATERIALS: The results of radiobiological experimental studies are reviewed for RBE for different fraction number and dose per fraction. RBE was always higher for fractionated neutrons based on comparison with isoeffective doses of photons. This is inherent in the basic radiobiological properties of photons. RBE was highest for low dose rate (LDR) Cf brachytherapy. RESULTS: Brachytherapy methods deliver radiation dose which is localized and conformal to the tumor. These methods have been used for Cf therapy and led to good tissue tolerance and local tumor control. The use of large dose/session (or fraction), small fraction number, short treatment times, followed by photon beam therapy has been the practice in Cf brachytherapy. It has been found that bulky or localized advanced tumors responded better if neutron treatment preceded the photon beam therapy. Therapeutic efficacy is dependent on the fraction size of neutrons and not the time duration of application. CONCLUSIONS: Available radiobiological data on neutron RBE with fraction number and size of dose and the favorable experience from Cf brachytherapy with up-front neutron applications suggest new avenues to explore for the neutron beam trials. The high efficacy noted for small volume dose, 10 to 20 Gy-eqs of dose per session, localized dose, conformal methods, small number of sessions, short treatment times and an up-front or early schedule in combining neutron and photon therapy suggests that similar schedules and methodology may also be effective for neutron beam therapy. Further clinical trials are indicated and bulky GYN tumors represents suitable tumors for study.

Animals↗
PubMed1993

Study of biological effects of varying mixtures of Cf-252 and gamma radiation on the acute radiation syndromes: relevance to clinical radiotherapy of radioresistant cancer.

PURPOSE: Data for the 30 day bone marrow syndrome (BM-50) and the 6-10 day gastrointestinal (GI-50) syndrome for a one and two fraction schedule and acute and low dose rate irradiation using pure and mixed Cf-252 and photon radiation are presented. METHODS AND MATERIALS: The radiations of Cf-252 is a mixture of neutrons and gamma rays. We total body irradiated Balb/c mice of both sexes with acute Co-60, low dose rate Cs-137 and Cf-252 using a 1 x and 2 x schedule. For low linear energy transfer radiations of Co-60 or Cs-137 there was expected to be an increase in the dose to produce the gastrointestinal and bone marrow syndromes with minimal change for Cf-252 neutrons. However, the radiations from Cf-252 are approximately 65% neutrons and approximately 35% photons and hence some repair may be expected. We further altered the proportion of photons in the Cf-252 radiation field by mixing Cs-137 with the Cf-252 sources and total body irradiated the mice to determine the effects on the syndromes. We determined the effects of mixing Cf-252 neutrons with different proportions of photons on the radiation syndromes. RESULTS: There was increase in BM-50 and GI-50 doses with fractionated or low dose rate photon irradiations and the dose modifying factors were 1.3-1.4 for the GI syndrome and 1.2 for the bone marrow syndrome. For Cf-252 there was minimal fractionation effect for the GI-50 syndrome, which increased by a 1.1 for x 1 vs. x 2 fractions; for the BM-50 syndrome it rose by a 1.1 factor. For LDR Cs-137 the dose for the GI-50 syndrome rose by a 2.2 fold. For mixed neutron-photon radiation of 0%, 15%, 35%, and 65% eta/gamma mixtures, the dose to produce the BM-50 and GI-50 endpoints dropped sharply from 0 to 35% neutrons and remained flat thereafter. CONCLUSION: For major tissues such as the bone marrow and G-I tract, Cf-252 behaved as high linear energy transfer for mixtures of neutrons and gamma rays of approximately 35% neutrons when the radiation were delivered simultaneously at the low dose rates studied. There was little or no additional contribution to the effectiveness of the mixed radiations if neutrons contributed 35% or more of the dose.

Animals↗
PubMed1993

Schedule in Cf-252 neutron brachytherapy: complications after delayed implant therapy for cervical cancer in a phase II trial.

The objective of this study was to review severe complication frequency in a protocol study using a defined prescribed dose combined with fractionated whole pelvis radiotherapy to 40-45 Gy. The method used a dose of Cf neutrons to 35 Gy equivalents (relative biological effectiveness or RBE adjusted) to a total tumor dose of 80 Gy-eq in one to four implant sessions. Compliance was excellent, and most patients received two implants to 35 (0.4) (SE) Gy-eq in two sessions plus external radiation to a total point A or paracervical region dose of 80 (0.3) Gy-eqs. In patients who received delayed implants, the severe complication rate (pelvic necrosis, fistulas) was significantly greater (40% versus 3%). We postulate that neutron brachytherapy caused tumors to regress rapidly and completely, which allowed the neutron dose to adjacent radiosensitive organs (bladder, rectum, sigmoid colon, and bowel) to become excessive. The delayed Cf implant apparently contributed to the greater risk for normal tissue complications.

Adult↗
PubMed1992

Tandem-vaginal cylinder applicator for radiation therapy of uterine adenocarcinoma.

Preoperative radiotherapy for stage II adenocarcinoma of the endometrium was studied in 74 patients using the University of Kentucky tandem-vaginal cylinder applicator. The intrauterine tandem and vaginal cylinder were inserted and loaded at the same time or sequentially. Forty to 45 Gy of fractionated whole pelvis photon radiotherapy was combined with the single intracavitary insertion which gave 20 Gy to a parauterine isodose at 2 cm and to the vaginal surface. Treatment with this system gave a 5 year survival rate of 88% with a 4% complication rate for stage II corpus adenocarcinomas.

Adenocarcinoma↗
PubMed1990

Regeneration in cervix cancer after 252Cf neutron brachytherapy.

Regeneration of clonogens in human cervical cancer was assessed by the pathological evaluation of the hysterectomy specimen after intracavitary 252Cf neutron brachytherapy implants separated by varying time intervals followed by extrafascial hysterectomy. In this study, patients with bulky/barrel shaped Stage IB cervical cancers received 252Cf implants plus approximately 45 Gy of whole pelvis linear accelerator radiotherapy in approximately 25 fractions in 5 weeks followed by hysterectomy 4-6 weeks after radiotherapy. The specimens were studied grossly and microscopically for residual tumor. It was found that the fraction of positive specimens increased with elapsed time interval between implants. These findings support the hypothesis that there is repopulation of surviving clonogens with increased time interval between the implants. The observation also supports current concerns that rapid depopulation of tumor can lead to rapid repopulation, that is, rapid shrinkage of tumor can alter the physiological environment such that clonogens can rapidly regenerate.

Brachytherapy↗
PubMed1990

Evaluation of time-dose and fractionation for 252Cf neutrons in preoperative bulky/barrel-cervix carcinoma radiotherapy.

Time-dose fractionation factors (TDF) were calculated for 252Cf (Cf) neutron therapy versus 137Cs for intracavitary use in the preoperative treatment of bulky/barrel-shaped Stage IB cervix cancers. The endpoint assessed was gross and microscopic tumor eradication from the hysterectomy specimen. We reviewed the data obtained in clinical trials between 1976-1987 at the University of Kentucky Medical Center. Preoperative photon therapy was approximately 45 Gy of whole pelvis irradiation in 5 weeks for both 137Cs and Cf treated patients. 137Cs implant was done after pelvic irradiation x1 to a mean dose of 2104 +/- 36 cGy at point A at a dose rate of 50.5 cGy/h. There were 37.5% positive specimens. Using Cf intracavitary implants, dose varied from 109 to 459 neutron cGy in 1-2 sessions. Specimens were more frequently cleared of tumor (up to 100% at appropriate dose) and showed a dose-response relationship, both by nominal dose and by TDF adjusted analysis of dose, dose-rate, number of sessions, and overall time. Limited understanding of relative biological effectiveness, schedule, effect of implants, and dose rate all made it difficult to use TDF to study neutron effects. Relative biological effectiveness (RBE) was estimated and showed that for Cf, RBE was a complex function of treatment variables. In the pilot clinical studies, a value of 6.0 had been assumed. The present findings of RBE for tumor destruction are larger than those assumed. Cf was effective for cervix tumor therapy and produced control without significant side effects due to the brachytherapy method used. The TDF model was of limited value in the present analysis and more information is still needed for RBE, dose-rate, and fractionation effects for Cf neutrons to develop a more sophisticated and relevant model.

Brachytherapy↗
PubMed1990

Clinical study of relative biological effectiveness for cervical carcinoma treated by 252Cf neutrons and assessed by histological tumour eradication.

Clinical data of the University of Kentucky trial using californium (252Cf), or caesium (137Cs), are reviewed for dose-response based on the endpoint of tumour eradication estimated from hysterectomy specimens obtained 4-6 weeks after preoperative irradiation. These data are used to assess the relative biological effectiveness (RBE) for 252Cf neutrons compared with 137Cs gamma radiation. Tumours treated were of common stage but were of bulky or barrel shape suitable for "radiosurgical" therapy. Dose-response curves were constructed, and additional data from the literature used to analyse the curve shape. The photon dose-response curve is complex on a logarithmic plot, whereas the 252Cf neutron curve is exponential. This indicates that the RBE can be different depending on the number of implants, schedule and size of dose delivered per session. The RBE values were approximately 8.0 at low doses or for multiple implants but they may rise to approximately 16 at larger doses or for single 252Cf implants.

Brachytherapy↗
PubMed1988

Neutron scattering cross sections and partial kerma values for oxygen, nitrogen and calcium at 18 less than En less than 60 MeV.

Recent measurements of differential elastic and inelastic neutron scattering from oxygen, nitrogen and calcium at 18 less than En less than 26 MeV are presented and analysed in terms of the optical model. These data, together with earlier measurements of scattering and total cross sections, are used to construct model potentials that may be used to calculate various quantities of interest in neutron dosimetry in an energy region (20-60 MeV) where very few cross section data are available. The heavy-ion-recoil contribution to kerma is obtained directly from the data at each energy. The value of proton inelastic scattering data for validating potential models at high energy is discussed.

Calcium↗