Autologous Islet Transplantation in Patients Requiring Pancreatectomy: A Broader Spectrum of Indications Beyond Chronic Pancreatitis.

Islet autotransplantation (IAT) is usually performed in patients undergoing pancreatic surgery for chronic pancreatitis. In the present series, IAT was offered also to patients undergoing pancreatic surgery for both nonmalignant and malignant diseases, having either completion pancreatectomy as treatment for severe pancreatic fistulas (n = 21) or extensive distal pancreatectomy for neoplasms of the pancreatic neck (n = 19) or pancreatoduodenectomy because of the high risk of pancreatic fistula (n = 32). Fifty-eight of 72 patients who were eligible to this broader spectrum of indication actually received IAT. There was no evidence of a higher-than-expected rate of major complications for pancreatectomy. Forty-five patients receiving IAT were still alive at the time of the last scheduled follow-up (1375 ± 365 days). Eighteen (95%) of 19 and 11 (28%) of 39 patients reached insulin independence after partial or total pancreatectomy, respectively. The metabolic results were dependent on the transplanted islet mass. Thirty-one of 58 patients had malignant diseases of the pancreas or periampullary region, and only three patients developed ex novo liver metastases after IAT (median follow-up 914 ± 382 days). Our data demonstrate the feasibility, efficacy, and safety of IAT for a broader spectrum of clinical indications beyond chronic pancreatitis.

Liver perfusion changes occurring during pancreatic islet engraftment: a dynamic contrast-enhanced magnetic resonance study.

The aim of this study was to investigate liver microvascular adaptation following the intraportal infusion of pancreatic islets (pancreatic islet transplantation [islet-tx]) in diabetic patients using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). DCE-MRI was performed before and 7 days after islet-tx in six diabetic patients. Initial area under curve (AUC60) and volume transfer coefficient (Ktrans) were assessed as markers of liver perfusion. Clinical and metabolic monthly follow-up was performed in all patients, considering fasting C-peptide and ß-score as main indices of graft function. High variability in the response of liver microvasculature to islet infusion was observed: two patients showed a significant reduction in liver perfusion after transplantation (pt.2: AUC60 = -23.4%, Ktrans = -31.7%; pt.4: AUC60 = -23.7%, Ktrans = -27.9%); three patients did not show any significant variation of liver perfusion and one patient showed a significant increase (pt.3: AUC60 = +31%, Ktrans = +42.8%). Interestingly, a correlation between DCE-MRI parameters and indices of graft function was observed and, in particular, both patients with DCE-MRI evidence of posttransplantation liver perfusion reduction experienced premature graft failure. Our preliminary study demonstrated that DCE-MRI may identify different adaptive responses of liver microvasculature in patients submitted to islet-tx. These different responses could have an impact on islet engraftment, although reported findings need confirmation from larger studies.

In-vitro effects of the tyrosine kinase inhibitor imatinib on glioblastoma cell proliferation.

Glioblastoma (GBL) is the most malignant brain tumour in adults, causing the death of most patients within 9-12 months of diagnosis. Treatment is based on a combination of surgery, radiation therapy, and chemotherapy. With these treatment modalities, however, responses are extremely poor, so identification of novel treatment strategies is highly warranted. Platelet-derived growth factors (PDGF) and their receptors are commonly coexpressed in GBL, suggesting that stimulation of autocrine PDGF receptors may contribute to their growth. Interest in these receptors as drug target for glioblastoma treatment has increased with the clinical availability of the PDGFR kinase inhibitor antagonist imatinib mesylate (STI571). In this study, T98G and A172 human GBL cell lines were analysed for their sensitivity to treatment with imatinib. In particular, we focussed our attention on analysis of DNA distribution by flow cytometry at different times of incubation with different imatinib concentrations (1-30 microM: ). Our results show that imatinib induces growth arrest in T98G and A172 cells in the G(0)/G(1) phase of the cell cycle, at all the concentrations tested, as early as 24 h after treatment. However we have also seen, by means of annexin V staining, that at 20 and 30 microM: concentrations, in concomitance with a significant growth arrest in the G(0)/G(1) phase, there is an increase of apoptotic cells 48 h after treatment, suggesting that imatinib at low concentrations (1-10 microM: ) could act as a cytostatic agent whereas at high concentrations (20, 30 microM: ) it mainly behaves as a cytotoxic agent.

Improving the procedure for detection of intrahepatic transplanted islets by magnetic resonance imaging.

Islet transplantation is an effective therapy for restoring normoglycemia in type-1 diabetes, but long-term islet graft function is achieved only in a minority of cases. Noninvasive magnetic resonance imaging of pancreatic islets is an attractive option for "real-time" monitoring of graft evolution. So far, previous studies have been performed in the absence of a standardized labeling procedure and, besides a feasibility study in patients, the effectiveness and safety of various labeling approaches were tested only with high field magnets (4.7 T). In this study, we addressed: (a) standardization of a labeling procedure for human islets with clinically-approved contrast agent Endorem, (b) safety aspects of labeling related to inflammation and (c) quality of imaging both at 7 T and 1.5 T. We have highlighted that the ratio of Endorem/islet is crucial for reproducible labeling, with a ratio of 2.24 ug/IEQ, allowing successful in vivo imaging both with 1.5 T and 7.0 T magnets up to 143 days after intrahepatic transplant. With this standardized labeling procedure, labeled islets are neither inflamed nor more susceptible to inflammatory insults than unlabeled ones. This report represents an important contribution towards the development of a standardized and safe clinical protocol for the noninvasive imaging of transplanted islets in humans.

In vitro assessment of radiobiology of meningioma: A pilot study.

BACKGROUND: Meningioma are the second most common brain tumors in adults and can cause significant morbidity and mortality. The scarcity of in vitro and in vivo models represents the major obstacle to understand the molecular basis of meningioma tumorigenesis. The main aim of this study was to assess a method for radiobiology of meningioma cells colture by means of well-known meningioma lines. NEW METHOD: We carried out a protocol of cells culture for irradiation of meningioma cells. We used the immortalized cell lines IOMM-Lee and CH-157 to study their radiation-reponse by means of clonogenic assays and to evaluate their proliferation and apoptosis. We irradiated the cells with different total doses using two different linear accelerators. RESULTS: We observed a more radiation resistance of the IOMM-Lee than the CH-157. Indeed, the cellular death of CH-157 was obtained at a very low dose irradiation. Moreover, we showed a dose-response effect due to the early and late apoptosis, in fact the rate of apoptotic cells is greater than that of the necrotic cells at any dose of irradiation and at any time of analysis. COMPARISON WITH EXISTING METHODS: There is not a standardized method for radiobiology of meningioma experiments. CONCLUSIONS: Our method of cells culture appears suitable for radiosensitivity studies on meningioma. We can confirm that the response to radiotherapy depends not only on irradiation features, but also on tumor radiosensitivity.

Proliferation and programmed cell death: role of p53 protein in high and low grade astrocytoma.

p53 is a cell cycle regulator that has been well-recognized as the key molecule that triggers the induction and the control of cell proliferation and apoptosis in a wide variety of tumours, including astrocytoma. Apoptosis and proliferation are two processes intimately coupled, that occur simultaneously in tumour tissue. Previous studies of the correlations between proliferation and apoptotic index with p53 expression in astrocytic tumours have remained inconclusive. The aim of this study was to investigate the correlation of p53 expression with the apoptotic index (AI) and the cell proliferation index (PI) in pilocytic astrocytoma (PA) and glioblastoma multiforme (GBM). A correlation of p53 expression with AI and PI was found in pilocytic astrocytoma but not in glioblastoma, probably because of the mutated p53 phenotype in the latter.

Exogenous platelet-derived growth factor (PDGF) induces human astrocytoma cell line proliferation.

Platelet-derived growth factor receptors (PDGFR) regulate several processes in normal cells including cellular proliferation, differentiation and migration, and are widely expressed in a variety of malignancies. In astrocytoma, PDGF ligand and receptor are often overexpressed and PDGFR activity deregulation has been linked to pathogenesis. The issue of the functional capacity of PDGFR has only occasionally been addressed in glioma cells by measuring the proliferative response induced by exogenous PDGF. In the present study, PDGFRalpha expression was evaluated in human grade 2 and 4 astrocytoma cell lines and tissue specimens by immunocytochemistry. The receptor responsiveness to exogenous PDGF was determined in astrocytoma cells with an MTT assay. It was found that astrocytoma cells express PDGFRalpha and respond to PDGF mitogenic action in a grade-dependent manner. The receptor was found to be functional since it induced cell proliferation at different ligand concentrations. We can thus conclude that the proliferative response of human astrocytoma cells is related to their malignancy and receptor status before PDGF stimulation, suggesting a role for PDGFRalpha inhibitors as blockers of malignant cell proliferation.

Surface properties and implantation site affect the capsular fibrotic overgrowth.

Transplantation of encapsulated pancreatic islets is a promising approach for the treatment of type 1 diabetes. Large-scale application of this technique, however, is hampered by insufficient biocompatibility of the capsules. In this study, we have evaluated the biocompatibility of a new synthetic material with six different chemical groups on their surface (amino, carboxy-sulfate, carboxylate, hydroxylate, sulfate, and PMMA) used for the fabrication of the microcapsules. Eight Lewis rats were inoculated with a suspension of empty capsules made for each candidate material in the retroperitoneal ileopsoas muscle and renal subcapsular space. Four weeks later kidney and muscle containing the capsules were explanted, paraffin embedded, sectioned and stained with Sirius Red and Masson's Trichrome for histological analysis. The amount of fibrosis was also ultrastructurally evaluated with scanning electron microscopy. The samples were then subjected to digitalized quantitative analysis using specific software to determine the degree of fibrotic overgrowth. The quantification of collagen deposition, calculated in proximity of the microcapsules, was expressed as a percentage of the total area and can be considered a good index for the biocompatibility, an essential prerequisite for functional pancreatic islet transplantation. The results show that subcapsular renal space is the best implantation site and the positive surface charge induces a more intense collagen synthesis.

Minichromosome maintenance protein 7: a reliable tool for glioblastoma proliferation index.

At present there is increasing evidence concerning the value of minichromosome maintenance (MCM) protein expression as a novel indicator of proliferation. In the present study, 15 glioblastoma samples, classified according to WHO, were analysed to evaluate the expression of the principal proliferation markers. The samples examined were subdivided into 2 cytological subsets, small cell (SC) or multiforme cell (MC) glioblastoma, according to the predominant cell type defined in individual specimens. MCM7 detected more cells in the cycle than Ki67 and PCNA and all cases of SC glioblastoma, the most aggressive subset, displayed a significant increase of MCM7-stained nuclei versus those stained with Ki67. These results suggest that the cell cycle-associated proteins MCM are not only useful markers of proliferation, but also valid aids for diagnosis in cerebral glioblastoma.

Immunohistochemical evaluation of minichromosome maintenance protein 7 in astrocytoma grading.

The minichromosome maintenance (MCM) proteins, which play an important role in eukaryotic DNA replication, represent a group of proteins that are currently under investigation as novel diagnostic tumor markers. Several studies have proved a greater reliability of MCM proteins to stain proliferating cells compared to Ki67 protein, a routinely used proliferation marker in histopathology. In the present study, the expressions of MCM7 and Ki67 were estimated in 66 primary human astrocytomas in relation to tumor grade (Grade I-IV, WHO). MCM7 significantly stained more nuclei compared to Ki67 in all the histopathological grades investigated. In addition, a stronger increase of the MCM7 labelling index, in relation to the tumor aggressiveness, was observed.

Histochemical study of cardiac mast cells degranulation and collagen deposition: interaction with the cathecolaminergic system in the rat.

Although their role in the cardiovascular system is still largely unknown, mast cells are present in the myocardium of both experimental animals and humans. Interestingly, cathecolaminergic nerve fibres and mast cells are often described in close morphological and functional interactions in various organs. In the present study we investigated the effects of chronic interference with beta-adrenergic receptors (via either sympathectomy or beta-blockade) on cardiac mast cell morphology/activation and on interstitial collagen deposition. In rats subjected to chemical sympathectomizy with the neurotoxin 6-hydroxydopamine (6-OHDA) we observed a significant increase of mast cell density, and in particular of degranulating mast cells, suggesting a close relationship between the cardiac catecholaminergic system and mast cell activation. In parallel, chronic 6-OHDA treatment was associated with increased collagen deposition. The influence of the beta-adrenergic receptor component was investigated in rats subjected to chronic propranolol administration, that caused a further significant increase in mast cell activation associated with a lower extent of collagen deposition when compared to chemical sympathectomy. These data are the first demonstration of a close relationship between rat cardiac mast cell activation and the catecholaminergic system, with a complex interplay with cardiac collagen deposition. Specifically, abrogation of the cardiac sympathetic efferent drive by chemical sympathectomy causes mast cell activation and interstitial fibrosis, possibly due to the local effects of the neurotoxin 6-hydroxydopamine. In contrast, beta-adrenergic blockade is associated with enhanced mast cell degranulation and a lower extent of collagen deposition in the normal myocardium. In conclusion, cardiac mast cell activation is influenced by beta-adrenergic influences.

Modelling radiation-induced bystander effect and cellular communication.

In the last 10 years evidence has accumulated on the so-called radiation-induced 'non-targeted effects' and in particular on bystander effects, consisting of damage induction in non-irradiated cells most likely following the release of soluble factors by the irradiated ones. These phenomena were observed for different biological endpoints, both lethal and non-lethal for the cell. Although the underlying mechanisms are largely unknown, it is now widely recognised that two types of cellular communication (i.e. via gap junctions and/or release of molecular messengers into the extracellular environment) play a pivotal role. Furthermore, the effects can be significantly modulated by parameters such as cell type and cell-cycle stage, cell density, time after irradiation etc. Theoretical models and simulation codes can be of help to improve our knowledge of the mechanisms, as well as to investigate the possible role of these effects in determining deviations from the linear relationship between dose and risk which is generally applied in radiation protection. In this paper three models, including an approach under development at the University of Pavia, will be presented in detail. The focus will be on the various adopted assumptions, together with their implications in terms of non-targeted radiobiological damage and, more generally, low-dose radiation risk. Comparisons with experimental data will also be discussed.

Gamma ray-induced bystander effect in tumour glioblastoma cells: a specific study on cell survival, cytokine release and cytokine receptors.

Recent experimental evidence has challenged the paradigm according to which radiation traversal through the nucleus of a cell is a prerequisite for producing genetic changes or biological responses. Thus, unexposed cells in the vicinity of directly irradiated cells or recipient cells of medium from irradiated cultures can also be affected. The aim of the present study was to evaluate, by means of the medium transfer technique, whether interleukin-8 and its receptor (CXCR1) may play a role in the bystander effect after gamma irradiation of T98G cells in vitro. In fact the cell specificity in inducing the bystander effect and in receiving the secreted signals that has been described suggests that not only the ability to release the cytokines but also the receptor profiles are likely to modulate the cell responses and the final outcome. The dose and time dependence of the cytokine release into the medium, quantified using an enzyme linked immunosorbent assay, showed that radiation causes alteration in the release of interleukin-8 from exposed cells in a dose-independent but time-dependent manner. The relative receptor expression was also affected in exposed and bystander cells.

Mechanisms of coordination of Ca2+ signals in pancreatic islet cells.

Within pancreatic islet cells, rhythmic changes in the cytosolic Ca2+ concentration have been reported to occur in response to stimulatory glucose concentrations and to be synchronous with pulsatile release of insulin. We explored the possible mechanisms responsible for Ca2+ signal propagation within islet cells, with particular regard to gap junction communication, the pathway widely credited with being responsible for coordination of the secretory activity. Using fura-2 imaging, we found that multiple mechanisms control Ca2+ signaling in pancreatic islet cells. Gap junction blockade by 18 alpha-glycyrrhetinic acid greatly restricted the propagation of Ca2+ waves induced by mechanical stimulation of cells but affected neither Ca2+ signals nor insulin secretion elicited by glucose elevation. The source of Ca2+ elevation was also different under the two experimental conditions, the first being sustained by release from inner stores and the second by nifedipine-sensitive Ca2+ influx. Furthermore, glucose-induced Ca2+ waves were able to propagate across cell-free clefts, indicating that diffusible factors can control Ca2+ signal coordination. Our results provide evidence that multiple mechanisms of Ca2+ signaling operate in beta-cells and that gap junctions are not required for intercellular Ca2+ wave propagation or insulin secretion in response to glucose.

High glucose causes apoptosis in cultured human pancreatic islets of Langerhans: a potential role for regulation of specific Bcl family genes toward an apoptotic cell death program.

Type 2 diabetes is characterized by insulin resistance and inadequate insulin secretion. In the advanced stages of the disease, beta-cell dysfunction worsens and insulin therapy may be necessary to achieve satisfactory metabolic control. Studies in autopsies found decreased beta-cell mass in pancreas of people with type 2 diabetes. Apoptosis, a constitutive program of cell death modulated by the Bcl family genes, has been implicated in loss of beta-cells in animal models of type 2 diabetes. In this study, we compared the effect of 5 days' culture in high glucose concentration (16.7 mmol/l) versus normal glucose levels (5.5 mmol/l) or hyperosmolar control (mannitol 11 mmol/l plus glucose 5 mmol/l) on the survival of human pancreatic islets. Apoptosis, analyzed by flow cytometry and electron and immunofluorescence microscopy, was increased in islets cultured in high glucose (HG5) as compared with normal glucose (NG5) or hyperosmolar control (NG5+MAN5). We also analyzed by reverse transcriptase-polymerase chain reaction and Western blotting the expression of the Bcl family genes in human islets cultured in normal glucose or high glucose. The antiapoptotic gene Bcl-2 was unaffected by glucose change, whereas Bcl-xl was reduced upon treatment with HG5. On the other hand, proapoptotic genes Bad, Bid, and Bik were overexpressed in the islets maintained in HG5. To define the pancreatic localization of Bcl proteins, we performed confocal immunofluorescence analysis on human pancreas. Bad and Bid were specifically expressed in beta-cells, and Bid was also expressed, although at low levels, in the exocrine pancreas. Bik and Bcl-xl were expressed in other endocrine islet cells as well as in the exocrine pancreas. These data suggest that in human islets, high glucose may modulate the balance of proapoptotic and antiapoptotic Bcl proteins toward apoptosis, thus favoring beta-cell death.

Early effects comparison of X-rays delivered at high-dose-rate pulses by a plasma focus device and at low dose rate on human tumour cells.

A comparative study has been performed on the effects of high-dose-rate (DR) X-ray beams produced by a plasma focus device (PFMA-3), to exploit its potential medical applications (e.g. radiotherapy), and low-DR X-ray beams produced by a conventional source (XRT). Experiments have been performed at 0.5 and 2 Gy doses on a human glioblastoma cell line (T98G). Cell proliferation rate and potassium outward currents (IK) have been investigated by time lapse imaging and patch clamp recordings. The results showed that PFMA-3 irradiation has a greater capability to reduce the proliferation rate activity with respect to XRT, while it does not affect IK of T98G cells at any of the dose levels tested. XRT irradiation significantly reduces the mean IK amplitude of T98G cells only at 0.5 Gy. This work confirms that the DR, and therefore the source of radiation, is crucial for the planning and optimisation of radiotherapy applications.

Effects of cryopreservation on in vitro and in vivo long-term function of human islets.

BACKGROUND: The possibility of performing transplantation several days after explant seems to be a peculiarity of islet grafts, and the opportunity to cryopreserve human islets may permit an indefinite period for modulating the recipient immune system. The aim of the present study was the evaluation of in vitro and in vivo functional properties of cryopreserved human islets. METHODS: We used six consecutive human islet preparations not suitable for an immediate transplantation in diabetic patients because the limited islet mass separated. The in vitro function of cryo and fresh islets was studied by determination of insulin and glucagon secretion in response to such classical stimuli as glucose (16.7 mM), glucose (16.7 mM) + 3-isobutyl-1-methylxanthine (0.1 mM), arginine (10 mM), and tolbutamide (100 microM). In vivo islet function was assessed through intravenous glucose tolerance tests performed at 15, 30, 60, and 90 days after transplantation of 1000 hand-picked fresh or cryopreserved islets in nude mice. RESULTS: Basal secretion of true insulin was significantly higher in cryopreserved islets than in fresh ones. The response of cryopreserved islets to arginine and glucose + isobutyl-1-methylxanthine seemed partially impaired. Proinsulin-like molecule secretion seemed higher in cryopreserved than in fresh islets in response to all secretagogues used, and the difference was statistically significant for arginine. The capacity of human cryopreserved islets to maintain a correct metabolic control in diabetic nude mice was progressively lost in 3 months. CONCLUSIONS: These findings showed that cryopreservation affects the function of isolated human islets, maintaining in vivo function for a limited period of time.

Developmental patterns in the rat cerebellum after cis-dichlorodiammineplatinum treatment.

A cytochemical study was made of some metabolic enzymes in the cerebellar neurons during postnatal ontogenesis after injection of cis-dichlorodiammineplatinum into 10-day-old rats. The profiles during development of neuron-specific enolase immunoreactivity (involved in the glycolytic pathway), dihydrofolate reductase activity (involved in the metabolism of nucleic acids and folate) and dipeptidylaminopeptidase II activity were determined in lobules V-VII of cerebellar vermis. At different developmental stages, treated rats had folia in which the morphology and cytochemical responses of Purkinje neurons were greatly affected. On postinjection day 1 (PD 11), only neuron-specific enolase immunoreactivity was changed, reactions being more intense at the basal pole, which was abnormally enlarged in several neurons. Seven days after treatment (PD 17), the dihydrofolate reductase reaction showed weakly positive cells with small grains of formazan in the perinuclear regions and dipeptidylaminopeptidase II activity, which had appeared at this time in some cells of the controls, was not observed. On PD 25 and PD 35, Purkinje cells, probably undergoing clear degeneration, were negative or very weakly positive in all the reactions. Some tracts of folia had no Purkinje cells. These results suggest that cis-dichlorodiammineplatinum affects the differentiation of Purkinje neurons and interferes first with the glycolytic enzyme and then with some enzymes of the synthetic and catabolic machinery, leading to cellular dysfunction and degeneration.

Factors determining the proton T1 relaxivity in solutions containing Gd-DTPA.

The relaxation times T1 and nuclear Overhauser effects were measured in the 13C nuclear magnetic resonance (NMR) spectra of the diamagnetic calcium (Ca) and lanthanum (La) analogs of Gd-DTPA. From these data the correlation times for the molecular reorientation tau R were calculated; it is suggested that this term is the dominant one in the evaluation of the paramagnetic relaxation equation. The similar tau R values obtained in water and blood serum ruled out the occurrence of any adduct formation between Gd-DTPA complex and the macromolecular framework in the latter system. The difference in relaxivity shown by Gd-DTPA in the two media is interpreted in terms of influence of the serum components on the dissociation equilibrium of Gd-DTPA.

A new class of contrast agents for magnetic resonance imaging based on selective reduction of water-T2 by chemical exchange.

Compounds containing mobile protons can act as contrast agents by increasing the value of the term (1/12 - 1/11). The efficiency of this method is markedly pH- and field-dependent. There are many such compounds allowing a choice to be made based on the characteristics of the tissue or organ, magnetic field strength, and solution pH levels. The properties of some of these chemicals have been investigated at different magnetic field strength and solution pH levels. The authors report herein the properties of iopamidol a well-known x-ray contrast agent, and stress its potential effect as an MRI contrast agent. The influence on the T2 decrease of the chemical shift separation delta omega (in frequency units) between water and exchangeable proton of the contrast agent may be increased by adding suitable shift reagents which interact with basic sites close to the protons involved in the chemical exchange.