Robotic spleen-preserving distal pancreatectomy: the Verona experience

BACKGROUND

The minimally invasive approach in spleen-preserving distal pancreatectomy has currently been emphasized in benign and pre-malignant pancreatic diseases. The study aims to demonstrate the safety and feasibility of our technique of robotic spleen-preserving distal pancreatectomy (RSPDP) by a stepwise approach.

METHODS

The data of consecutive patients presented for RSPDP from 2014 to 2019 at Verona University were retrieved from a prospectively maintained database. The patients were divided into two groups based on the surgical procedure performed, such as Kimura's (KG) or Warshaw's (WG) technique, and then compared.

RESULTS

In the study period, 32 patients underwent RSPDP. Twenty-three patients presented for the Kimura procedure (72%), while nine patients underwent the Warshaw procedure (28%). A higher body mass index was found in the KG (26 ± 4 vs. 22 ± 3, p = 0.037). Regarding the pathological data, the WG group differed in the tumor dimension, and the lymph nodes harvested (30 ± 2 vs. 17 ± 10, 9 ± 5 vs. 3 ± 4, p = 0.0028, and p = 0.005, respectively). Notably, no conversions and mortality were recorded. The overall morbidity was 25% ( eight patients) with no difference between the groups (p = 0.820). The mean length of stay was 8 days, and was similar between the groups (p = 0.350).

CONCLUSIONS

The present study suggests that RSPDP is a valid option for the treatment of benign or pre-malignant pancreatic diseases of the distal pancreas, with comparable morbidity with the standard treatment and no mortality. Further research is needed to standardize the technique and to assess the immunological, surgical, and financial benefits of the procedure.

Outcomes of Primary Chemotherapy for Borderline Resectable and Locally Advanced Pancreatic Ductal Adenocarcinoma

Importance

Chemotherapy is the recommended induction strategy in borderline resectable and locally advanced pancreatic ductal adenocarcinoma. However, the associated results on an intention-to-treat basis are poorly understood.

Objective

To investigate pragmatically the treatment compliance, conversion to surgery, and survival outcomes of patients with borderline resectable and locally advanced pancreatic ductal adenocarcinoma undergoing primary chemotherapy.

Design, Setting, and Participants

This prospective study took place in a national referral center for pancreatic diseases in Italy. Consecutive patients with borderline resectable and locally advanced pancreatic ductal adenocarcinoma were enrolled at the time of diagnosis (January 2013 through December 2015) and followed up to June 2018.

Exposures

The chemotherapy regimen, assigned based on multidisciplinary evaluation, was delivered either at a hub center or at spoke centers. By convention, primary chemotherapy was considered completed after 6 months. After restaging, surgical candidates were selected based on radiologic and biochemical response. All surgeries were carried out at the hub center.

Main Outcomes and Measures

Rates of receipt and completion of chemotherapy, rates of conversion to surgery, and disease-specific survival.

Results

Of 680 patients, 267 (39.3%) had borderline resectable and 413 (60.7%) had locally advanced pancreatic ductal adenocarcinoma. Overall, 66 patients (9.7%) were lost to follow-up. The rate of chemotherapy receipt was 92.9% (n = 570). The chemotherapeutic regimens most commonly used included FOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and irinotecan) (260 [45.6%]) and gemcitabine plus nanoparticle albumin-bound-paclitaxel (123 [21.6%]). Nineteen patients (3.3%) receiving chemotherapy died within 6 months, mainly for disease progression. The treatment completion rate was 71.6% (408 of 570). The overall rate of resection was 15.1% (93 of 614) (borderline resectable, 60 of 249 [24.1%]; locally advanced, 33 of 365 [9%]; resection:exploration ratio, 63.3%). Independent predictors of resection were age, borderline resectable disease, chemotherapy completion, radiologic response, and biochemical response. The median survival for the whole cohort was 12.8 (95% CI, 11.7-13.9) months. Factors independently associated with survival were completion of chemotherapy, receipt of complementary radiation therapy, and resection. In patients who underwent resection, the median survival was 35.4 (95% CI, 27.0-43.7) months for initially borderline resectable and 41.8 (95% CI, 27.5-56.1) months for initially locally advanced disease. No pretreatment and posttreatment factors were associated with survival after pancreatectomy.

Conclusions and Relevance

This pragmatic observational cohort study with an intention-to-treat design provides real-world evidence of outcomes associated with the most current primary chemotherapy regimens used for borderline resectable and locally advanced pancreatic ductal adenocarcinoma.

Long term outcome after minimally invasive and open Warshaw and Kimura techniques for spleen-preserving distal pancreatectomy: International multicenter retrospective study

BACKGROUND

The Warshaw (WT) and the Kimura (KT) techniques are both used for open or minimally invasive (MI) spleen preserving distal pancreatectomy (SPDP). Multicenter studies on long-term outcome of WT and KT are lacking.

METHODS

Multicenter retrospective study with transversal follow-up moment, including patients who underwent SPDP from 2000 to 2017 at three high-volume centers in Italy and the Netherlands. Primary endpoint was the incidence of short and long term complications. Patients without regular follow-up were interviewed about symptoms and complications.

RESULTS

In total, 164 patients were enrolled, 55 WT (33.5%) and 109 kT (66.5%), of which 95 (57.9%) MI. There was no 30-day mortality (0%).The only significant difference in short-term outcome was more delayed gastric emptying (DGE) after WT (9.1% vs 1.8%, p = 0.043). MI-SPDP was associated with less blood loss (median 150 vs 250 ml, respectively, p < 0.001), less DGE (0% vs 10%, p = 0.002), less abdominal abscesses (8.4% vs 18.4%, p = 0.03) and less splenic infarctions (3.2% vs. 13%, p = 0.042), than open SPDP. Long-term follow-up (median 41 months) was available for 111 patients (67.7%) of whom 18 (16.2%) had an SPDP-related long-term sequela, mostly perigastric varices (n = 11, 9%) but without differences between WT and KT. Less long-term sequelae were reported after MI as compared to open SPDP (12.5% vs 21.2%, p = 0.032).

CONCLUSIONS

In this international retrospective study, the WT and KT had comparable short- and long-term outcomes. If a KT does not seem feasible during SPDP, a WT is recommended, rather than performing a splenectomy. MI-SPDP was associated with less short- and long term complications as compared to an open SPDP.

Pancreatectomy with venous resection for pT3 head adenocarcinoma: Perioperative outcomes, recurrence pattern and prognostic implications of histologically confirmed vascular infiltration

BACKGROUND

The outcomes of pancreatectomy with superior mesenteric vein (SMV) or portal vein (PV) resection have been mixed. This study investigated the morbidity and mortality profile after SMV-PV resection in comparison with standard pancreatectomy. Furthermore, we assessed whether tumors with histologically proven SMV-PV infiltration differ from other pT3 neoplasms in terms of recurrence pattern and survival.

METHODS

All patients with a pT3 head adenocarcinoma resected from 2000 to 2013 were analyzed retrospectively. In the SMV-PV resection group, information on venous wall status was obtained through pathologic reports. Standard statistical methods were used for data analysis.

RESULTS

The study population consisted of 651 patients, of whom 81 (12.4%) underwent synchronous SMV-PV resection. Venous resection was not associated with a higher rate of postoperative complications (60.5% versus 50.2%) and mortality (1.2% versus 1.1%) in comparison with standard pancreatectomy. Vascular infiltration was confirmed pathologically in 56/81 patients (69.1%). The median disease-specific survival of the entire population was 27 months (95% CI 24.6-29.3), with a 5-year survival rate of 20.5%. The median recurrence-free survival was 18 months (95% CI 15.0-20.9). On multivariate analysis, ASA score, preoperative pain, Ca 19-9 levels, tumor grade, R-status, lymph-vascular invasion, N-status, and adjuvant therapy resulted to be survival predictors. Similarly, Ca 19.9 levels, R-status, and N-status were predictors of recurrence. SMV-PV infiltration was not a significant prognostic factor.

CONCLUSION

Morbidity and mortality rates of pancreatectomy with SMV-PV resection are comparable with standard pancreatectomy. Pancreatic head adenocarcinoma with histologically confirmed SMV-PV infiltration does not segregate prognostically from other pT3 tumors.

Nutrient intake of Swiss toddlers

PURPOSE

During the first years of life, food preferences are shaped that might last throughout a person's entire life affecting his/her health in the long term. However, knowledge on early feeding habits is still limited for toddlers. Therefore, the goal of the present study was to: (1) assess toddlers' nutrient intake; (2) compare the findings to past studies as well as to national feeding recommendations and (3) identify major food sources for energy and macronutrients.

METHODS

A food survey using a 4-day diary was conducted. The dietary software nut.s^® was used to analyse the data.

RESULTS

A cohort of 188 healthy toddlers (aged 1-3 years) was analysed. The energy intake of most toddlers was below the recommended daily intake (RDI) but in accordance with earlier studies. Protein intake was three- to fourfold higher than the RDI and reached the proposed upper limit of 15% of total energy intake. Fat intake was in accordance with the RDI, but the balance of saturated and unsaturated fatty acids should be improved. Carbohydrate intake met the RDI. For the micronutrients, iron and vitamin D intakes showed critical values.

CONCLUSION

As in other European countries, the diet of Swiss toddlers in general seems adequate but does not meet all nutritional requirements. In particular, the quality of the fats and vitamin D supplementation should be improved. For proteins and iron, additional research is needed to gain more confidence in the recommendations.

Pancreaticoduodenectomy in patients ≥ 75 years of age: Are there any differences with other age ranges in oncological and surgical outcomes? Results from a tertiary referral center

AIM

To compare surgical and oncological outcomes after pancreaticoduodenectomy (PD) in patients ≥ 75 years of age with two younger cohorts of patients.

METHODS

The prospectively maintained Institutional database of pancreatic resection was queried for patients aged ≥ 75 years (late elderly, LE) submitted to PD for any disease from January 2010 to June 2015. We compared clinical, demographic and pathological features and survival outcomes of LE patients with 2 exact matched cohorts of younger patients [≥ 40 to 64 years of age (adults, A) and ≥ 65 to 74 years of age (young elderly, YE)] submitted to PD, according to selected variables.

RESULTS

The final LE population, as well as the control groups, were made of 96 subjects. Up to 71% of patients was operated on for a periampullary malignancy and pancreatic cancer (PDAC) accounted for 79% of them. Intraoperative data (estimated blood loss and duration of surgery) did not differ among the groups. The overall complication rate was 65.6%, 61.5% and 58.3% for LE, YE and A patients, respectively, P = NS). Reoperation and cardiovascular complications were significantly more frequent in LE than in YE and A groups (P = 0.003 and P = 0.019, respectively). When considering either all malignancies and PDAC only, the three groups did not differ in survival. Considering all benign diseases, the estimated mean survival was 58 and 78 mo for ≥ and < 75 years of age (YE + A groups), respectively (P = 0.012).

CONCLUSION

Age is not a contraindication for PD. A careful selection of LE patients allows to obtain good surgical and oncological results.

Is there a role for near-infrared technology in laparoscopic resection of pancreatic neuroendocrine tumors? Results of the COLPAN "colour-and-resect the pancreas" study

BACKGROUND

The intraoperative identification of pancreatic neuroendocrine tumors (PanNETs) is of utmost importance to drive their laparoscopic resection. Near-infrared (NIR) surgery has emerged as a new technique for localizing tumors or neoplastic tissue. This study aimed to explore the results of the application of NIR in the laparoscopic resection of PanNETs.

METHODS

Per protocol we enrolled ten subjects undergoing laparoscopic pancreatic surgery for PanNET from March 2016 to October 2016. During surgery, the patients were injected with indocyanine green dye (ICG, 25 mg given in 5 boli of 5 mg each). The switch-activation of NIR was performed to identify PanNETs. An ex-post analysis of the images was realized using ImageJ Software® to calculate the fluorescence signal.

RESULTS

NIR imaging identified all ten PanNETs. Nine (90%) laparoscopic distal pancreatectomy with splenectomy and one (10%) laparoscopic enucleation were performed. The mean maximum tumor dimension was 2.4 cm (range 1-4 cm). Eight non-functioning PanNETs (80%) and two insulinomas (20%) were found at the final pathology. Nine out of ten (90%) PanNETs were detected after the second ICG bolus. The mean latency time was 80 s and the mean visibility time was 220 s. The peak of tumor visualization was reached 20 min after the last bolus. This finding was confirmed by the ex-post analysis of the fluorescence signal (mean signal-to-background ratio of 7.7, p = 0.001). NIR identified two additional lesions, which turned out to be normal lymph nodes at final pathology. A fluorescent signal was identified at the bed of the enucleation, and thus, a further exeresis was performed and final pathology revealed that is was residual neoplastic tissue.

CONCLUSIONS

This explorative study shows that NIR with ICG can have a role in laparoscopic pancreatic resection of PanNETs. Further studies are needed to assess the proper setting and role of this new and promising technology.

Assessment of a complication risk score and study of complication profile in laparoscopic distal pancreatectomy

OBJECTIVE

This study assessed the patient-specific risk for major postoperative morbidity in a series of 100 laparoscopic distal pancreatectomies (LDP).

METHODS

A previously established complication risk score (CRS), identifying body mass index (BMI), estimated blood loss (EBL), and pancreatic specimen length as determinants of postoperative morbidity were examined against the observed outcomes. In addition, multivariate analyses were performed to investigate risk factors specific to our study population.

RESULTS

The postoperative morbidity rate was 49 %, major complication accounted for 12 %, and clinically relevant pancreatic fistulae (PF) were 13 %. The incidence of any complications, major complications, any PF, and clinically relevant PF did not vary appreciably when the CRS increased. The multivariate analysis indicated that male sex and an EBL ≥150 mL were independent predictors of major morbidity and clinically relevant PF.

CONCLUSION

In conclusion, the previously published CRS based on pre- and intraoperative factors was not able to predict the postoperative risk in our population. This is probably because risk scores may not be able to adjust for the case-mix (heterogeneity in baseline patient characteristics). According to our data, men and patients with EBL ≥150 mL are more likely to develop major postoperative complications after LDP.

Viability and stress protection of chronic lymphoid leukemia cells involves overactivation of mitochondrial phosphoSTAT3Ser727

Chronic lymphoid leukemia (CLL) is characterized by the accumulation of functionally defective CD5-positive B lymphocytes. The clinical course of CLL is highly variable, ranging from a long-lasting indolent disease to an unpredictable and rapidly progressing leukemia requiring treatment. It is thus important to identify novel factors that reflect disease progression or contribute to its assessment. Here, we report on a novel STAT3-mediated pathway that characterizes CLL B cells-extended viability and oxidative stress control. We observed that leukemic but not normal B cells from CLL patients exhibit constitutive activation of an atypical form of the STAT3 signaling factor, phosphorylated on serine 727 (Ser₇₂₇) in the absence of detectable canonical tyrosine 705 (Tyr₇₀₅)-dependent activation in vivo. The Ser₇₂₇-phosphorylated STAT3 molecule (pSTAT3Ser₇₂₇) is localized to the mitochondria and associates with complex I of the respiratory chain. This pSer₇₂₇ modification is further controlled by glutathione-dependent antioxidant pathway(s) that mediate stromal protection of the leukemic B cells and regulate their viability. Importantly, pSTAT3Ser₇₂₇, but neither Tyr705-phosphorylated STAT3 nor total STAT3, levels correlate with prolonged in vivo CLL B cells survival. Furthermore, STAT3 activity contributes to the resistance to apoptosis of CLL, but not normal B cells, in vitro. These data reveal that mitochondrial (Mt) pSTAT3Ser₇₂₇ overactivity is part of the antioxidant defense pathway of CLL B cells that regulates their viability. Mt pSTAT3Ser₇₂₇ appears to be a newly identified cell-protective signal involved in CLL cells survival. Targeting pSTAT3Ser₇₂₇ could be a promising new therapeutic approach.

Modeling hydration water and its role in polymer folding

The hydrophobic effect is the dominant force which drives a proteintowards its native state, but its physics has not been thoroughlyunderstood yet. We introduce an exactly solvable model of the solvation ofnon-polar molecules in water, which shows that the reduced number ofallowed configurations of water molecules when the solute is present isenough to give rise to hydrophobic behaviour. We apply our model to anon-polar homopolymer in aqueous solution, obtaining a clear evidence ofboth `cold' and `warm' collapse transitions that recall those of proteins.Finally we show how the model can be adapted to describe the solvation ofaromatic and polar molecules.

Perioperative and long-term results after left pancreatectomy: a single-institution, non-randomized, comparative study between open and laparoscopic approach

BACKGROUND

Laparoscopic left pancreatic resections are being increasingly performed. In this study, we provide a nonrandomized comparison between laparoscopic and open left pancreatectomy (OLP) for benign and borderline tumors, focusing on both perioperative and long-term results.

METHODS

Demographic, pathologic, and perioperative details from patients who underwent laparoscopic and OLP between 1999 and 2006 were retrieved from our database and analyzed. Long-term results, including resume to full-time work, occurrence of incisional hernias, and incidence of exocrine and endocrine insufficiency also were evaluated.

RESULTS

A total of 116 patients were included in the analysis; 43 (37.1%) were managed laparoscopically and 73 (62.9%) underwent the open procedure. There were no significant differences regarding clinical and pathological data. All of the resections attempted laparoscopically were completed. The rate of splenic preservation was significantly higher in the laparoscopic group (P = 0.0001). Postoperative outcomes were similar between the two groups. Longitudinal comparison between two time periods (1999-June 2004 vs. July 2004-2006) showed that pancreatic fistula and hospital stay significantly diminished over time in the laparoscopic group (P = 0.04 and P = 0.004, respectively). Median follow-up was 53 months. The incidence of exocrine insufficiency and incisional hernias was significantly higher after open resections (both P = 0.05). After hospital discharge, median time to resume full-time work was 6 weeks in the open group and 3 weeks after laparoscopic resections (P < 0.0001). Laparoscopy also resulted as an independent factor for an early resume to full-time activities in the multivariate analysis (P < 0.0001).

CONCLUSIONS

Laparoscopic left pancreatectomy is a safe procedure for benign and borderline tumors, with similar perioperative outcomes compared with the open procedure. In the long term, the laparoscopic approach is likely to be superior thanks to a more rapid resume of full-time activities and to the lower incidence of incisional hernias and exocrine insufficiency. Clearly, these results have yet to be confirmed in large, randomized trials.

Vibrational entropy and the structural organization of proteins

In this paper we analyze the vibrational spectra of a large ensemble of non-homologous protein structures by means of a novel tool, that we coin Hierarchical Network Model (HNM). Our coarse-grained scheme accounts for the intrinsic heterogeneity of force constants displayed by protein arrangements and also incorporates side chain degrees of freedom. Our analysis shows that vibrational entropy per unit residue correlates with the content of secondary structure. Furthermore, we assess the individual contribution to vibrational entropy of the novel features of our scheme as compared with the predictions of state-of-the-art network models. This analysis highlights the importance of properly accounting for the intrinsic hierarchy in force strengths typical of the different atomic bonds that build up and stabilize protein scaffolds. Finally, we discuss possible implications of our findings in the context of protein aggregation phenomena.

"Paraduodenal" pancreatitis: results of surgery on 58 consecutives patients from a single institution

BACKGROUND

Cystic dystrophy of heterotopic pancreas, groove pancreatitis, pancreatic hamartoma of the duodenum, paraduodenal wall cyst, and myoadenomatosis are all terms grouped together, from a pathological viewpoint, as definitions of paraduodenal pancreatitis (PP). The objective of the present study was to investigate the clinical characteristics, therapeutic strategies, and results in 58 patients undergoing pancreatic resection for PP.

METHODS

From January 1990 to December 2006 data were prospectively collected on 58 patients who were diagnosed with PP who then underwent pancreaticoduodenectomy.

RESULTS

In this patient cohort the median age was 44.7 years; only 4 patients were women, and only 3 had non-drinker and/or non smoker habits. The overall morbidity was 18.9%, and the median hospitalization was 11 days. There were no postoperative deaths. In a median follow-up of 96.3 months, all patients noted a decrease in the pain associated with PP; 35 patients (76%) had complete disappearance of pain, whereas occasional relapsing pain occurred in the remaining 11 (24%).

CONCLUSIONS

Patients with PP have clinical characteristics similar to those of chronic pancreatitis. The diagnostic imaging modalities of choice are ultrasonographic endoscopy and magnetic resonance cholangiopancreaticography. Based on our surgical experience, pancreaticoduodenectomy seems to be a reasonable choice of treatment in patients with PP.

Laparoscopic distal pancreatectomy: results on a consecutive series of 58 patients

OBJECTIVE

To describe the clinical characteristics, indications, technical procedures, and outcome of a consecutive series of laparoscopic distal pancreatic resections performed by the same surgical team.

SUMMARY BACKGROUND DATA

Laparoscopic distal pancreatic resection has increasingly been described as a feasible and safe procedure, although accompanied by a high rate of conversion and morbidity.

METHODS

A consecutive series of patients affected by solid and cystic tumors were selected prospectively to undergo laparoscopic distal pancreatectomy performed by the same surgical team. Clinical characteristics as well as diagnostic preoperative assessment and intra- and postoperative data were prospectively recorded. A follow-up of at least 3 months was available for all patients.

RESULTS

Fifty-eight patients underwent laparoscopic resection between May 1999 and November 2005. All procedures were successfully performed laparoscopically, and no patient required intraoperative blood transfusion. Splenic vessel preservation was possible in 84.4% of spleen-preserving procedures. There were no mortalities. The overall median hospital stay was 9 days, while it was 10.5 days for patients with postoperative pancreatic fistulae (27.5% of all cases). Follow-up was available for all patients.

CONCLUSIONS

Our experience in 58 consecutive patients was characterized by the lack of conversions and by acceptable rates of postoperative pancreatic fistulae and morbidity. Laparoscopy proved especially beneficial in patients with postoperative complications as they had a relatively short hospital stay. Solid and cystic tumors of the distal pancreas represent a good indication for laparoscopic resection whenever possible.

Intraductal papillary mucinous neoplasms and chronic pancreatitis

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) may present with clinical and radiological pictures resembling those of chronic pancreatitis (CP).

AIMS

To compare the clinical and epidemiological characteristics of patients suffering from CP with those of patients suffering from IPMN. To assess whether CP is associated with an increased risk of developing IPMN.

METHODS

In our departments, from 1981 to 1998, we prospectively followed 473 patients suffering from CP, including 93 cases of chronic obstructive pancreatitis (COP), and 45 patients with a histologically confirmed diagnosis of IPMN. Another 6 patients had an initial diagnosis of CP and a subsequent diagnosis of IPMN.

RESULTS

Patients with IPMN were more often female (females 53 vs. 15%; p < 0.001), were older (mean age 63.1 vs. 42.8 years; p < 0.001), drank less alcohol (19 vs. 107 g/day; p < 0.001) and smoked fewer cigarettes (mean 8 vs. 21 cigarettes/day) than CP patients. These results were also confirmed when considering only patients with COP. The 6 patients with a subsequent diagnosis of IPMN were males (p n.s.) with a mean age of 51.4 years (p < 0.05). Only 1 patient was a drinker (p < 0.05) and 4 were smokers (p n.s.). Comparing CP and IPMN, logistic regression analysis selected sex, age, alcohol and smoking, whereas only sex and age were selected when comparing COP vs. IPMN.

CONCLUSIONS

In general patients with IPMN present different epidemiological characteristics than those with CP and the subgroup with COP. The clinical and pathological features suggest that in most cases IPMN is the cause of CP and not vice versa.

Long-term results of Frey's procedure for chronic pancreatitis: a longitudinal prospective study on 40 patients

Only limited prospective data are available regarding the long-term outcome of local resection of the pancreatic head in combination with longitudinal pancreaticojejunostomy in patients with chronic pancreatitis. From 1997 to 2001, 40 patients affected by chronic pancreatitis were subjected to the Frey's procedure. Preoperative selection criteria included confirmed diagnosis of chronic pancreatitis, dilation of Wirsung's duct to a diameter greater than 6 mm, and the absence of obstructive chronic pancreatitis secondary to fibrotic stenosis at the pancreatic body or tail. Preoperative pain was present in 38 cases (95%), and follow-up was performed in all patients at least once yearly up to 2003 (median 60 months, inter percentile range 20.1-79.6). Postoperative morbidity occurred in three cases (7.5%). The percentage of pain-free patients was 94.7%, 93.7%, 87.5%, and 90% at 1, 2, 3, and 4/5 years after surgical operation, respectively. After surgery, three patients developed diabetes. Both the body mass index and quality of life showed statistically significant improvements at all follow-up intervals. Whenever surgery is indicated, the short-term and long-term outcomes confirm that Frey's procedure is an appropriate means of management for patients with chronic pancreatitis in the absence of doubts of neoplasia and/or distal ductal obstruction.

Model for the hydration of nonpolar compounds and polymers

We introduce an exactly solvable statistical-mechanical model of the hydration of nonpolar compounds, based on grouping water molecules in clusters where hydrogen bonds and isotropic interactions occur; interactions between clusters are neglected. Analytical results show that an effective strengthening of hydrogen bonds in the presence of the solute, together with a geometric reorganization of water molecules, are enough to yield hydrophobic behavior. We extend our model to describe a nonpolar homopolymer in aqueous solution, obtaining a clear evidence of both "cold" and "warm" swelling transitions. This suggests that our model could be relevant to describe some features of protein folding.

Previous cholecystectomy, gastrectomy, and diabetes mellitus are not crucial risk factors for pancreatic cancer in patients with chronic pancreatitis

INTRODUCTION

In the general population, cholecystectomy, diabetes, and chronic pancreatitis seem to be associated with an increased risk of developing pancreatic cancer.

AIMS

We assessed whether previous cholecystectomy, gastrectomy, or diabetes mellitus may be risk factors for pancreatic cancer in patients with chronic pancreatitis.

METHODOLOGY

We analyzed 853 patients with chronic pancreatitis (110 women, 743 men) with a median follow-up period of 14 years with particular reference to establishing which patients had previously undergone cholecystectomy or distal gastric resection (Billroth II anastomosis) or had diabetes or gallstone disease and the respective time scales involved.

RESULTS

Pancreatic cancer developed in 17 patients with chronic pancreatitis after a median period of 8 years from onset of pancreatitis symptoms (range, 3-38 years). Excluding two cholecystectomies performed 1 year before diagnosis of cancer, cholecystectomy was performed in 7/17 (41%) patients with pancreatic cancer and in 381/836 (46%) of the other patients with chronic pancreatitis. Forty-nine (10%) patients with chronic pancreatitis and no pancreatic cancer had undergone cholecystectomy during the years before the onset of chronic pancreatitis, whereas none of the patients in whom a pancreatic malignancy developed had undergone cholecystectomy before the onset of chronic pancreatitis symptoms. Gastrectomies were performed in 116 patients (14%), 47 before the onset of chronic pancreatitis. Only 2/17 patients with pancreatic cancer had undergone previous gastrectomy, though in both cases only shortly before diagnosis of the cancer. Diabetes was diagnosed in 353 patients, but only in 30 (4%) before onset of chronic pancreatitis. Only 1/17 patients (6%) with pancreatic cancer had long-standing diabetes, whereas diabetes developed in 3/17 shortly before diagnosis of pancreatic cancer.

CONCLUSIONS

Cholecystectomy, gastrectomy, and diabetes are not major risk factors for the development of pancreatic cancer in patients with chronic pancreatitis.

[Clinical evolution of chronic pancreatitis and quality of life]

Nowadays the availability of reliable, efficacious methods of assessing the outcome of chronic pancreatitis is mandatory, especially in view of the several new procedures developed to relieve the symptoms of the disease. Together with the traditional evaluation of postoperative morbidity and mortality and the assessment of exo/endocrine function in patient follow-up, we currently consider the patient's perception of his or her health status as a priority. This information is obtained by administering quality of life questionnaires along with reliable physical and psychometric evaluation.

Assessment and treatment of severe pancreatitis. Protease inhibitor

From the theoretical point of view, antiproteolytic therapy would seem to be the rationale for acute pancreatitis management. Unfortunately, clinical human trials studying the role of antiproteases in the treatment of acute pancreatitis differ in several respects in terms of their basic design. As a consequence, any form of homogeneous analysis of the reported data as a whole is impossible. Considering the data emerging from a meta-analysis of five trials a rational use of antiproteases may result in a reduction of complications requiring surgery and of patient management costs only in selected cases, meaning by that severe and necrotic forms. As regards presumptive applications, over 400 patients were prospectively tested versus placebo in a double-blind trial with the aim of preventing acute pancreatitis after ERCP. The complication incidence was significantly lower among the pretreated patients; anyway, also in this field of protease inhibitor clinical application it is necessary to identify the patients with the greatest risk to develop post-ERCP acute pancreatitis. In conclusion, antiproteases can still play a role when given prophylactically or when used in the very early phases of the disease; moreover a 'multiple drugs approach' (including, for example, suitable antibiotics) seems to represent nowadays the most modern and rational treatment of acute pancreatitis.