Cell death following BNCT: a theoretical approach based on Monte Carlo simulations.

In parallel to boron measurements and animal studies, investigations on radiation-induced cell death are also in progress in Pavia, with the aim of better characterisation of the effects of a BNCT treatment down to the cellular level. Such studies are being carried out not only experimentally but also theoretically, based on a mechanistic model and a Monte Carlo code. Such model assumes that: (1) only clustered DNA strand breaks can lead to chromosome aberrations; (2) only chromosome fragments within a certain threshold distance can undergo misrejoining; (3) the so-called "lethal aberrations" (dicentrics, rings and large deletions) lead to cell death. After applying the model to normal cells exposed to monochromatic fields of different radiation types, the irradiation section of the code was purposely extended to mimic the cell exposure to a mixed radiation field produced by the (10)B(n,α) (7)Li reaction, which gives rise to alpha particles and Li ions of short range and high biological effectiveness, and by the (14)N(n,p)(14)C reaction, which produces 0.58 MeV protons. Very good agreement between model predictions and literature data was found for human and animal cells exposed to X- or gamma-rays, protons and alpha particles, thus allowing to validate the model for cell death induced by monochromatic radiation fields. The model predictions showed good agreement also with experimental data obtained by our group exposing DHD cells to thermal neutrons in the TRIGA Mark II reactor of the University of Pavia; this allowed to validate the model also for a BNCT exposure scenario, providing a useful predictive tool to bridge the gap between irradiation and cell death.

Boron uptake measurements in a rat model for Boron Neutron Capture Therapy of lung tumours.

Lung carcinoma is the leading cause of cancer mortality in the Western countries. Despite the introduction over the last few years of new therapeutic agents, survival from lung cancer has shown no discernible improvement in the last 20 years. For these reasons any efforts to find and validate new effective therapeutic procedures for lung cancer are very timely. The selective boron uptake in the tumour with respect to healthy tissues makes Boron Neutron Capture Therapy a potentially advantageous option in the treatment of tumours that affect whole vital organs, and that are surgically inoperable. To study the possibility of applying BNCT to the treatment of diffuse pulmonary tumours, an animal model for boron uptake measurements in lung metastases was developed. Both healthy and tumour-bearing rats were infused with Boronophenylalanine (BPA) and sacrificed at different time intervals after drug administration. The lungs were extracted, and prepared for boron analysis by neutron autoradiography and α-spectroscopy. The boron concentrations in tumour and normal lung were plotted as a function of the time elapsed after BPA administration. The concentration in tumour is almost constant within the error bars for all the time intervals of the experiment (1-8 h), while the curve in normal lung decreases after 4 h from BPA infusion. At 4 h, the ratio of boron concentration in tumour to boron concentration in healthy lung is higher than 3, and it stays above this level up to 8 h. Also the images of boron distribution in the samples, obtained by neutron autoradiography, show a selective absorption in the metastases.

In vitro and in vivo studies of boron neutron capture therapy: boron uptake/washout and cell death.

Boron neutron capture therapy (BNCT) is a binary radiotherapy based on thermal-neutron irradiation of cells enriched with (10)B, which produces α particles and (7)Li ions of short range and high biological effectiveness. The selective uptake of boron by tumor cells is a crucial issue for BNCT, and studies of boron uptake and washout associated with cell survival studies can be of great help in developing clinical applications. In this work, boron uptake and washout were characterized both in vitro for the DHDK12TRb (DHD) rat colon carcinoma cell line and in vivo using rats bearing liver metastases from DHD cells. Despite a remarkable uptake, a large boron release was observed after removal of the boron-enriched medium from in vitro cell cultures. However, analysis of boron washout after rat liver perfusion in vivo did not show a significant boron release, suggesting that organ perfusion does not limit the therapeutic effectiveness of the treatment. The survival of boron-loaded cells exposed to thermal neutrons was also assessed; the results indicated that the removal of extracellular boron does not limit treatment effectiveness if adequate amounts of boron are delivered and if the cells are kept at low temperature. Cell survival was also investigated theoretically using a mechanistic model/Monte Carlo code originally developed for radiation-induced chromosome aberrations and extended here to cell death; good agreement between simulation outcomes and experimental data was obtained.

Experimental modified orthotopic piggy-back liver autotransplantation.

UNLABELLED: The classical orthotopic liver autotransplantation is a very challenging and time wasting technique; it includes the division of major hepatic vessels and choledocus, and subsequent reconnection by end to end anastomoses. The caval end to end anastomoses are the most difficult to be performed and the interposition of a prosthesis can be required. We adopted the classical orthotopic liver autotransplantation technique in 2 patients affected with diffused liver metastases from colorectal cancer, for extracorporeal neutron capture therapy (BNCT). The procedure required very long operating times and the extracorporeal circulation (ECC) set up; furthermore the vena cava reconstruction was performed by the interposition of a goretex-prosthesis. We propose a "modified orthotopic piggy-back technique" to simplify liver reconnection and shorten the operating time. MATERIALS AND METHODS: The technique was developed in the swine (25 kg body weight), under general anaesthesia. We performed the resection of the retro-hepatic vena cava with preservation of the caval flow during the anhepatic phase, by interposing a goretex-prosthesis. The reconstruction of the vena cava was then performed by a side-to-side cava-prosthesis anastomosis with lateral clamping of the prosthesis. The procedure was then completed according to the classical technique of liver transplantation. RESULTS: The mean time for VC reconstruction was 56 (+/-10)min. and the mean time for side-to-side VC-prosthesis anastomosis was 13(+/-4)min. CONCLUSIONS: The "modified orthotopic piggy-back technique" can simplify the reimplant of the liver during autotransplantation and shorten the operating time. Furthermore also the time of total extracorporeal circulation is reduced, as during the anhepatic phase and during the side-to-side cava-prosthesis anastomosis the flow in the inferior vena cava is uninterrupted.

Calculations of dose distributions in the lungs of a rat model irradiated in the thermal column of the TRIGA reactor in Pavia.

To test the possibility to apply boron neutron capture therapy (BNCT) to lung tumors, some rats are planned to be irradiated in the thermal column of the TRIGA reactor of the University of Pavia. Before the irradiation, lung metastases will be induced in BDIX rats, which will be subsequently infused with boronophenylalanine (BPA). During the irradiation, the rats will be positioned in a box designed to shield the whole animal except the thorax area. In order to optimize the irradiation set-up and to design a suitable shielding box, a set of calculations were performed with the MCNP Monte Carlo transport code. A rat model was constructed using the MCNP geometry capabilities and was positioned in a box with walls filled with lithium carbonate. A window was opened in front of the lung region. Different shapes of the holder and of the window were tested and analyzed in terms of the dose distribution obtained in the lungs and of the dose absorbed by the radiosensitive organs in the rat. The best configuration of the holder ensures an almost uniform thermal neutron flux inside the lungs (Phi(max)/Phi(min)=1.5), an irradiation time about 10 min long, to deliver at least 40 Gy(w) to the tumor, a mean lung dose of 5.9+/-0.4 Gy(w), and doses absorbed by all the other healthy tissues below the tolerance limits.

Extra-corporeal liver BNCT for the treatment of diffuse metastases: what was learned and what is still to be learned.

Almost eight years ago, in December 2001, we performed for the first time in the world thermal neutron irradiation on an isolated liver of a patient. The organ was affected by diffuse metastases of a colon carcinoma and had been previously loaded with a (10)B compound. In July 2003, the same procedure was applied again on a patient for the treatment of unresectable and incurable hepatic metastases of a carcinoma of the rectum. Both patients are dead at present. Now we can analyze in depth the clinical history of these patients and evaluate the effectiveness of this therapy. From this exciting experience we learned much, and we also found out about complications till then unknown, which need to be studied and addressed experimentally. Unfortunately we can base our conclusions just on the experience we had with these two patients. We could have been much more detailed and firm in our statements if the number of clinical cases was larger. The BNCT Pavia project has been suspended, but it is more than likely to resume in a short time. Good findings were many. The procedure is feasible; the original concept of complete immersion of the diseased liver in a homogeneous neutron field proved effective and winning. The tumor masses resulted completely necrotic and unknown metastases too appeared radically treated; healthy hepatic tissue was preserved from both morphological and functional points of view; no symptoms of cirrhosis appeared even four years after treatment. For the long term surviving patient, quality of life was excellent. Other findings require to be tackled in depth. The "post-irradiation syndrome" we observed in both patients, with identical symptoms and biochemical derangements, creates a dramatic--even though totally reversible--clinical condition, that is the probable cause of death for our second patient, suffering from cardiomyopathy, 33 days after treatment. For the first patient, recurrences were a late yet fatal complication, for which even a further surgical revision was ineffective. We offer some hypotheses about their origin and possible prevention.

Selective uptake of p-boronophenylalanine by osteosarcoma cells for boron neutron capture therapy.

Osteosarcoma is the most common non-hematologic primary cancer type that develops in bone. Current osteosarcoma treatments combine multiagent chemotherapy with extensive surgical resection, which in some cases makes necessary the amputation of the entire limb. Nevertheless its infiltrative growth leads to a high incidence of local and distant recurrences that reduce the percentage of cured patients to less than 60%. These poor data required to set up a new therapeutic approach aimed to restrict the surgical removal meanwhile performing a radical treatment. Boron neutron capture therapy (BNCT), a particular radiotherapy based on the nuclear capture and fission reactions by atoms of (10)B, when irradiated with thermal neutrons, could be a valid alternative or integrative option in case of osteosarcoma management, thanks to its peculiarity in selectively destroying neoplastic cells without damaging normal tissues. Aim of the present work is to investigate the feasibility of employing BNCT to treat the limb osteosarcoma. Boronophenylalanine (BPA) is used to carry (10)B inside the neoplastic cells. As a first step the endocellular BPA uptake is tested in vitro on the UMR-106 osteosarcoma cell line. The results show an adequate accumulation capability. For the in vivo experiments, an animal tumor model is developed in Sprague-Dawley rats by means of an intrafemoral injection of UMR-106 cells at the condyle site. The absolute amounts of boron loading and the tumor to normal tissue (10)B ratio are evaluated 2 h after the i.v. administration of BPA. The boron uptake by the neoplastic tissue is almost twice the normal one. However, higher values of boron concentration in tumor are requested before upholding BNCT as a valid therapeutic option in the treatment of osteosarcoma.

Neutron autoradiography imaging of selective boron uptake in human metastatic tumours.

The ability to selectively hit the tumour cells is an essential characteristic of an anti-tumour therapy. In boron neutron capture therapy (BNCT) this characteristic is based on the selective uptake of (10)B in the tumour cells with respect to normal tissues. An important step in the BNCT planning is the measurement of the boron concentration in the tissue samples, both tumour and healthy. When the tumour is spread through the healthy tissue, as in the case of metastases, the knowledge of the different kinds of tissues in the sample being analysed is crucial. If the percentage of tumour and normal tissues cannot be evaluated, the obtained concentration is a mean value depending on the composition of the different samples being measured. In this case an imaging method that could give information both on the morphology and on the spatial distribution of boron concentration in the sample would be a fundamental support. In this paper, the results of the boron uptake analysis in the tumour and in the healthy samples taken from human livers after boron phenylalanine (BPA) infusion are shown; boron imaging was performed using neutron autoradiography.

How to study boron biodistribution in liver metastases from colorectal cancer.

The purpose of this study was to evaluate boron distribution for a safe and effective BNCT (Boron Neutron Capture Therapy) of liver metastases. Samples both from healthy and tumour liver parenchyma were analysed, after i.v. boron administration, by: alpha particles counting under neutron irradiation; morphological analysis by standard haematoxylin-eosin staining; neutron autoradiography. Our method was unaffected by the cytological heterogeneity inside tumour nodules; it demonstrated selective boron distribution in tumour tissue and predicted estimated mean therapeutic doses in tumour and safety doses in healthy tissue. The time interval for efficient BNCT was 2 to 4 hours after i.v. boron administration.

[Whole pancreatic transplantation and islet transplantation. Experiment notes]. / Trapianto di pancreas intero e trapianto di isole. Note sperimentali.

BACKGROUND: The results of pancreas transplantation have greatly improved in recent years. The path to further improvements goes through extensive experimental researches. METHODS: This study describes the effects of different procedures as hemodynamic asset and postoperative outcome. Twenty-nine swine underwent a total pancreatectomy, and were stratified into five groups. Group one (n = 5) served as control. Group two (n = 7) was autotransplanted. Group three (n = 6) and group four (n = 6) underwent allotransplantation; the first without immunosuppression and the second treated with cyclosporine and steroids. In group five (n = 5) Langerhans Islets transplantation was performed. RESULTS: Survival was different depending on which methodology was applied. The postoperative survival was 7 +/- 2 days in group one, 24 +/- 16 days in group two, 17 +/- 7 days in group three, 27 +/- 8 days in group four and 12 +/- 6 days in group five. CONCLUSIONS: The postoperative glucose control was normal in group two and group four while a severe diabetes appeared in group one (group 1 vs group 2: p < 0.05) and in group three during acute graft rejection after the 12th postoperative day (group 3 vs group 4: p < 0.05). Glycemia was slightly controlled in group five. The intraoperative hemodynamic status was evaluated at the time of pancreatectomy, harvesting, revascularization, and when surgery was over. Among the different parameters studied (mean arterial and pulmonary pressure, pulmonary wedge pressure, central venous pressure, cardiac output, oxygen extraction ratio, systemic vascular resistance, oxygen delivery and oxygen consumption), a statistically significant difference between group one and group five (p < 0.05) was observed.

Radioimmunoassisted surgery for lung metastases from colorectal cancer: results and perspectives.

The high incidence of resectable lung metastases from colorectal cancer and the very poor prognosis of untreated patients (less than 24-month survival) has promoted the surgical approach to treatment. Since the main aims of this kind of surgery are the complete resection of the tumor, the preservation of tumor-free parenchyma, and a minimal surgical trauma, innovative surgical techniques have been developed. We report on our experience in the radioimmunoassisted pulmonary metastasectomy by the use of a hand-held gamma-detecting probe (GDP) and describe the application of the intraoperative radioimmunolocalization of tumor to video-assisted minimally invasive surgery.

[Duodenal schwannoma. Clinical considerations]. / Schwannoma duodenale. Considerazioni cliniche.

The recent observation of a case of schwannoma in the second part of the duodenum lead the authors to a literature survey in order to state the present knowledge of this subject. Schwannoma is an ectodermal neoplasm arising from the nerve sheath that envelop axons. In the gastrointestinal tract these tumours can concern cells of the myentericus and submucosus plexus of the intestinal wall. A duodenal location is extremely rare. Gastroduodenal endoscopy, abdominal ultrasonography and CT scan were found as important investigatory tools, but only histological examination of the excised tissue suggests the definitive diagnosis. Therapy consists in the radical excision of the tumour; this is rarely obtained by endoscopic way because of the submucosal neoplastic growth. Then a surgical laparotomic approach is more often required and it allows to perform local excisions through a duodenotomy, partial duodenectomy or ampullectomy and more complex operations, like a cephalic duodenopancreatectomy, in front of extended papillar involvement. The latter was the suitable treatment for radical removing of the juxtapapillar schwannoma reported by the authors; the uneventful postoperative course, the patient's excellent general conditions and nutriture at 12 months confirm the validity of the therapeutic policy.

Catheter seeding of hepatocellular carcinoma following placement of a total implantable access port system.

A 61-year-old cirrhotic patient underwent hepatic resection for hepatocellular carcinoma and placement of a total implantable access port system in the hepatic artery for chemotherapy infusion. A year later, he developed a parietal metastasis at the port site as a consequence of tumor seeding along the arterial catheter. The metastasis was excised but the patient died because of disseminated disease two years after the first operation. Tumor seeding along the catheter should be included in the group of potential complications after placement of total implantable access port systems for intrahepatic chemotherapy The possible causes of this rare but life-threatening complication are discussed.

Internal mammary blood supply for ileo-colon interposition in esophagogastroplasty: a case report.

We report on a clinical case where microsurgical techniques successfully supported traditional surgery in a wide reconstruction between the oropharynx and small bowel. Several years ago, the patient sustained a severe corrosive injury of the upper digestive tract with subsequent esophageal stricture and stiffening; at that time, an emergency gastrectomy was performed. In this case, the restoration of the defect could not rely on the classic colonic interposition. During the operation the ileo-colic flap, well-fitted for tension-free reconstruction, revealed the foreseen inadequacy of its vascularization based on the sole middle colic vascular pedicle. The blood supply to its proximal part was then increased by microanastomosis between the right internal mammary and ileo-colic vessels. The revascularization ensured the viability of the interposed tissue. Oral intake resumed after 3 weeks; nowadays the patient is able to maintain her ideal weight with adequate nutrition.

[Flexibility of the surgical model of intestinal transplantation in swine]. / Flessibilità del modello chirurgico di trapianto intestinale sperimentale nel suino.

AIM: To verify the feasibility to introduce variations in the technique of intestinal transplantation, we developed three different intestinal transplant models in pigs. EXPERIMENTAL DESIGN: Feasibility and comparative study. ENVIRONMENT: Pre-clinical organ transplant surgery. MATERIALS AND METHODS: Sixty outbread piglets (mean weight 27.1 +/- 4.4 kg) received a total orthotopic intestinal allograft from equivalent donors perfused through the aorta with UW solution at 4 degrees C. Intraluminal flushing of the graft was always avoided. The animals were divided in 3 groups according to the transplantation procedure adopted. Group 1 (n = 9): excision of small and large bowel and replacement with small bowel only; group 2 (n = 39): excision of small bowel and its replacement; group 3 (n = 12): excision of small and large bowel and their "en-bloc" replacement. The superior mesenteric artery and vein were anastomosed end-to-end in all groups. RESULTS: The lowest perioperative mortality occurred in group 2 (28%), followed by group 3 (58%) and group 1 (78%). However, in group 1 the incidence of perioperative deaths was influenced by our learning curve in surgical and anesthesiologic management. No significant differences were noted in terms of cold and warm ischaemia time of the grafts, length of operative time, histopathologic analysis of preservation injury. The addition of the colon in the transplanted graft resulted in a more critical hemodynamic profile at reperfusion. CONCLUSION: Three different experimental models of intestinal transplantation are feasible in pigs. The choice can be made based on the type of study needed.

Combined immunosuppressive therapy with tacrolimus and mycophenolate mofetil for small bowel transplantation in pigs.

In a swine model of orthotopic small bowel transplantation, we assessed the efficacy of combined therapy with a low dose of tacrolimus plus mycophenolate mofetil, compared with high-dose tacrolimus monotherapy. The bowel was replaced in 25 piglets: group 1 (n = 5), no immunosuppression; group 2 (n = 10), tacrolimus, 0.3 mg/kg daily i.m. for 7 days, followed by b.i.d. oral doses to maintain blood levels of 15-25 ng/ml; and group 3 (n = 10), tacrolimus, 0.1 mg/kg i.m., in a single dose on day 0 and thereafter oral doses to maintain blood levels of 5-15 ng/ml, plus oral mycophenolate mofetil (10 mg/kg twice daily). Follow-up time was limited to 60 days. Median survival time as 11, 27, and > 60 days in groups 1, 2, and 3, respectively (P = 0.001). Survival rates were 0%, 40%, and 80% at 30 days and 0%, 0%, and 70% at 60 days in groups 1, 2, and 3, respectively (P = 0.03), group 1 vs. group 2; P = 0.003, group 1 vs. group 3; P = 0.02, group 2 vs. group 3). One animal in group 1 (20%) and two animals each in groups 2 and 3 (20%) died of technical complications. Rejection was the cause of death of 80% of animals of group 1 and of no animals in either group 2 or 3. None of the immunosuppressed animals developed clinical or histopathological evidence of graft-versus-host disease. Sixty percent of animals in group 2 (n = 6) and 10% in group 3 (n = 1) died from infections; two other animals in group 2 died of emaciation. The seven animals of group 3 that were alive at 60 days had immunosuppression stopped at that time. All died of rejection within 1 month. In conclusion, double-drug therapy with tacrolimus and mycophenolate mofetil consistently allowed extended survival after small bowel transplantation in swine, preventing or controlling acute cellular rejection without a high incidence of lethal complications related to overimmunosuppression.

A rare case of pancreatic lipoma.

During CT scanning, a pancreatic lipoma was diagnosed in a 70 year-old woman presenting with abdominal pain, elevated amylase and abnormal liver function tests. The patient underwent surgical excision of the lipoma located in the head of the pancreas. The postoperative course was uneventful. This is the third case of pancreatic lipoma described in the literature. It is a very rare neoplasm that should be included in the category of "non-ductal" tumors of the pancreas. The role of different diagnostic tools for the differential diagnosis of ductal pancreatic adenocarcinoma is discussed.