Role of CT in detecting malignancy during follow-up of patients with branch-type IPMN of the pancreas

BACKGROUND/AIMS

This retrospective study evaluated the suitability of computed tomography (CT) to detect malignancy while following patients with branch-type IPMN, most of which are benign and may be treated with observation alone.

METHODOLOGY

Forty-two surgical specimens resected from patients with a diagnosis of branch-type IPMN were pathologically classified as benign (n=26), which included hyperplasia and adenoma, or malignant (n=16), including moderate dysplasia or adenocarcinoma. It was compared the differences in the sizes of the tumor and main pancreatic duct (MPD) and the presence of mural nodules on CT between the groups.

RESULTS

In the malignant group, it was observed a larger tumor size (47.8 vs. 23.8 mm; p = 0.001) and increased dilation of the MPD (9.3 vs. 5.0 mm; p = 0.001) than those seen in the benign group. The accuracy of CT diagnosis of mural nodules, however, was only 62%. Tumor diameter > or =40 mm or MPD diameter >10 mm predicted malignancy with a sensitivity and negative predictive value of 93.8% and 95.7%, respectively.

CONCLUSIONS

Either tumor size or MPD dilation detected by CT could predict the majority of malignant branch-type IPMNs. Increases in these morphological characteristics on CT images during the follow-up period would be an accurate method to predict a diagnosis of malignancy.

First Report of Colletotrichum boninense Causing Anthracnose on Pepper in Brazil

Colletotrichum boninense was isolated from pepper (Capsicum annuum) fruits (cv. Amanda) with preharvest anthracnose symptoms collected in the Brazilian states of Rio Grande do Sul and São Paulo in July of 2005. In the field, the disease affected mature fruits and leaves with an incidence near 25%. Typical symptoms in fruits were circular, sunken lesions with orange spore masses in a dark center. Three single conidia isolates were obtained from infected fruits. When grown on potato dextrose agar at 25°C with a 12-h photoperiod, these isolates produced white colonies with a cream-to-orange color in the opposite side, but no sclerotia. Conidia were cylindrical, had obtuse ends and a hilum-like low protuberance at the base, and measured 13.5 to 15.5 × 4.6 to 5.1 μm. Conidial length/width ratio was 2.8 to 3.0. These morphological characteristics are consistent with the description of C. boninense (1). To confirm pathogen identity, the internal transcribed spacer rRNA region was sequenced (GenBank Accession Nos. FJ010199, FJ010200, and FJ010201) and compared with the same region of C. boninense (GenBank Accession No. DQ286160.1). Similarity between these sequences was 98 to 99%. The pathogenicity of the three isolates was determined on pepper fruits cv. Amanda. Attached as well as detached fruits from potted plants were inoculated. Inoculation was performed by depositing 40-μl droplets of a suspension (10⁵ conidia per ml) on the surfaces of nonwounded (detached n = 5; attached n = 5) and wounded (detached n = 5; attached n = 5) fruits with a sterilized hypodermic needle. Incubation took place in a moist chamber for 12 days at 25°C with a 12-h photoperiod. Inoculation of control fruits was similar in procedure and number to that of test fruits, except sterile distilled water was used instead of the conidial suspension. Symptoms, observed in wounded and nonwounded test fruits 3 to 5 days after inoculation, were characterized by necrotic, sunken zones containing acervuli, black setae, and orange spore masses. Control fruits presented no symptoms. Pathogens reisolated from infected fruits showed the same morphological and molecular characteristics of the isolates previously inoculated. To our knowledge, this is the first report of C. boninense infecting pepper in Brazil. Reference: (1) J. Moriwaki et al. Mycoscience 44:47, 2003.

77 SUCCESSFUL CRYOPRESERVATION OF SYRIAN HAMSTER OVARIES BY VITRIFICATION

In place of gametes, ovaries can be used as an alternative resource for cryopreservation. At the previous IETS meeting, we showed that in the Syrian hamster, pups could be successfully produced through the transplantation of fresh ovaries. In addition, the immunotolerance of interstrain ovarian transplantation was described. In this study, we attempted to produce pups via transplantation of cryopreserved ovaries to foster mothers. Our goal was to establish a preservation method for hamster strains based on ovarian cryopreservation in combination with ovarian transfer. Ovaries were cryopreserved by vitrification according to methods described for mouse ovaries (Migishima F et al. 2003 Biol. Reprod. 68, 881–887). In brief, ovaries were collected from 2- to 3-week-old HAW strain (white coat) females. Each ovary was cut into 4 sections, placed into 1 tube, and cryopreserved by vitrification using DAP213 solution (2 m dimethyl sulfoxide, 1 m acetamide, and 3 m propylene glycol; Nakagata N 1989 J. Reprod. Fertil. 87, 479–483). Thawed ovaries were transferred into the ovarian bursae (2 ovarian sections per ovarian bursa) of 3-week-old recipient females with agouti coat (Slc:Syrian) under anesthesia with isoflurane. Half of the recipients’ ovaries were removed immediately before transfer; i.e. both donor and recipient ovaries were present in each ovarian bursa. Successful ovarian transplantation was verified by examining the coat color (non-agouti color) of offspring produced in test matings between mature recipients and Slc:Syrian males. Out of 6 recipients tested, 2 became pregnant and delivered pups. According to the coat color of the pups, 1 of the 2 recipients delivered a pup produced from transplanted ovaries (1 out of 4 pups). Regardless of this low success rate, our results indicate that pups can be produced from cryopreserved ovaries via interstrain transplantation of ovaries to foster mothers in the Syrian hamster. Thus, ovarian cryopreservation by vitrification is a promising strategy for strain preservation of the Syrian hamster. This work was supported by a grant from the Ministry of Health, Labor, and Welfare, Japan.

Efficacy of the electrothermal bipolar vessel sealer in laparoscopic spleen-preserving distal pancreatectomy with conservation of the splenic artery and vein

INTRODUCTION

Laparoscopic spleen-preserving distal pancreatectomy (LSPDP) with conservation of the splenic artery and vein has recently been performed as a minimally invasive surgery to retain splenic function in the treatment of pancreatic diseases. As the branches of the splenic vessels are very delicate, division of these branches increases the risk of bleeding.

MATERIALS AND METHODS

To overcome this problem, we have used the electrothermal bipolar vessel sealer (EBVS) to divide branches of the splenic vessels in LSPDP while conserving the splenic vessels themselves.

RESULTS

The EBVS reliably provided excellent and safe hemostasis, minimizing the risk of serious blood loss.

CONCLUSION

Use of the EBVS is safe and efficient in LSPDP with conservation of the splenic vessels.

Analysis of appositional bone formation using a novel rat experimental model

AIM

To analyze the process of appositional bone formation using our original rat experimental model.

MATERIALS AND METHODS

Rats were anesthetized and a ring made of polytetrafluorethylene was placed on the parietal bone surface in the surgical procedure. The time course of appositional bone formation was analyzed with histomorphometry and in situ hybridization for type I collagen and bone sialoprotein.

RESULTS

The rat experimental model allowed new bone to be formed on the pre-existing bone surface and persist for 12 weeks. We demonstrated that bone is apposed actively for the first 4 weeks and less actively thereafter.

CONCLUSIONS

The experimental model may contribute to biological analysis for appositional bone formation expected to occur in clinical procedures such as alveolar bone augmentation and sinus lifting.

Bone regeneration by synthetic octacalcium phosphate and its role in biological mineralization

Octacalcium phosphate (Ca8H2(PO4)6 * 5H2O; OCP) has been advocated to be a precursor of biological apatite crystals in bone and tooth. Recent studies, using physical techniques, showed that OCP is present as a transient phase during biological apatite formation in human dentin, porcine enamel and murine bone. However, there is still a controversy regarding the chemical nature of the first mineral formed in the biominerals. A number of studies have demonstrated that synthetic OCP shows bone regenerative and biodegradable characteristics, rather than other calcium phosphate bone substitute materials, such as hydroxyapatite (Ca10(PO4)6(OH)2; HA) ceramic. It seems likely that synthetic OCP may be an alternative to autogenous bone graft. It is known that OCP contains alternative layers of water molecules and an apatite structure, and that the transition of OCP to HA is likely to be spontaneous and irreversible. The conversion process induces modification of local environment adjacent to OCP surface, including the changes in adsorption of serum proteins and concentration of calcium and inorganic phosphate ions. This article reviews the possible application to bone regeneration by synthetic OCP and the mechanism to enhance bone regeneration in relation to biological mineralization in bone and tooth.

Laparoscopic pancreaticoduodenectomy is effective in a porcine model

BACKGROUND

Laparoscopic pancreatic surgery is rapidly evolving due to improving instrumentation and surgical techniques. The challenges confronting laparoscopic pancreaticoduodenectomy (LPD), however, are its technical difficulty and its appropriateness for oncologic treatment. This study sought to develop a novel technique for LPD in an acute porcine model and to evaluate the safety and feasibility of LPD before clinical trials are undertaken.

METHODS

The LPD procedure was performed in 10 pigs. Modified Child's reconstruction was performed intracorporeally. After the animals were killed, anastomotic sites were investigated by laparotomy.

RESULTS

All the animals underwent LPD. The median operation time was 5 h, with minimal blood loss. One choledochojejunostomy had a small leak.

CONCLUSIONS

The study proved LPD to be technically safe and feasible in an acute porcine model. Further studies and technical advances are necessary for transition of this clinical application of LPD to humans.

Computed tomography evaluation of regional lymph node metastases in patients with biliary cancer

BACKGROUND

Identification of lymph node metastases in biliary cancer is important for determining prognosis and surgical planning, but the effectiveness of computed tomography (CT) in diagnosing node metastases of the hepatoduodenal ligament (peribiliary and retroportal nodes) or around the common hepatic artery is unknown.

METHODS

CT scans and pathological results from 146 patients who had undergone regional lymphadenectomy for biliary carcinoma were reviewed. To evaluate the regional lymph nodes, long- and short-axis diameters of lymph nodes were measured and axial ratios calculated (short-axis diameter/long-axis diameter). Nodes were considered round if the axial ratio exceeded 0.7. Internal lymph node structures were also evaluated.

RESULTS

The presence of a round node with a short-axis diameter exceeding 16 mm had a positive predictive value (PPV) of 56 per cent for the presence of metastatic foci, and node heterogeneity had a PPV of 64 per cent. The highest PPV (67 per cent) was obtained for round nodes greater than 18 mm in short-axis diameter, but nodes of this size and character were rare.

CONCLUSION

CT is not useful for predicting regional lymph nodal metastases in biliary carcinoma.

148 PRODUCTION OF PUPS BY OVARIAN TRANSFER IN THE SYRIAN HAMSTER

Instead of gametes, ovaries could be used as alternative resources for cryopreservation. In this study, we attempted to produce pups by transplantation of fresh ovaries to foster mothers as a first step to establish a preservation method of hamster strains on the basis of the cryopreservation of ovaries in combination with ovarian transfers. We also checked the possibility of inter-strain transfers of ovaries, since immunological tolerance among hamster strains is suggested by the fact that most Syrian hamsters were derived from only a small number of animals. Fresh ovaries collected from 3-weekold females of HAW (white coat) and APA (albino) strains were transferred into ovarian bursae of 3-week-old recipient females with agouti-coat (Slc:Syrian) under anesthesia with xylazine and ketamine. Halves of ovaries of recipients were removed immediately before the transfers, i.e., both donor and recipient ovaries were present in each ovarian bursa. Successful transplantation of ovaries was checked by the coat color (non-agouti color) of offspring produced by test matings of recipients with Slc:Syrian males after the recipients became mature. Five and six recipients received HAW and APA ovaries, respectively. All 11 recipients tested became pregnant and delivered pups. According to the coat color of the pups, three of five recipients which received HAW ovaries and one of six recipients which received APA ovaries delivered pups derived from transplanted ovaries (two out of eight pups, one out of seven pups, and three out of 11 pups for HAW; one out of five pups for APA). Our results indicate that transplantation of fresh ovaries to foster mothers could be used for production of pups from grafted ovaries in the Syrian hamster. In particular, immunological tolerance for ovarian transfers among at least three strains suggests that recipient strains might not need to be the same as donor strains for practical ovarian transfers in the Syrian hamster. Our results would facilitate the development of a strain preservation system for the Syrian hamster based on ovarian cryopreservation. This work was supported by a grant from the Ministry of Health, Labor, and Welfare of Japan.

Proliferation and adhesion of periodontal ligament cells on synthetic biominerals

OBJECTIVE

Hydroxiapatite (HA) has been suggested as a useful biomaterial to support the regeneration of tissues. In this study, we investigated the adhesion of periodontal ligament (PDL) cells on octacalcium phosphate (OCP) and its hydrolyzed apatitic product (HL), which are known precursors of HA.

METHODS

Rat PDL cells were cultured on OCP or HL-coated dishes. Cell proliferation and adhesion and mRNA expression of collagen I, fibronectin integrin subunits were examined. Cell adhesion inhibition assays were carried out by GRGDSPK (Gly-Arg-Gly-Asp-Ser-Pro-Lys).

RESULTS

In early culture period, the cell number of PDL cells was lower on OCP and HL than that on control without any coating. However, the cell number on OCP or HL caught up with control later period. mRNA expression level of collagen I and fibronectin on OCP and HL were similar among OCP HL and control, although they differed early in the culture period. Integrin subunits were expressed on both OCP and HL as well as on control. Cell adhesion was inhibited by RGD inhibitor peptide.

CONCLUSION

Our findings indicated that rat PDL cells produce collagen I and fibronectin on OCP and HL, and then show increased cell numbers depending on adhesion to the matrices through integrins.

Treatment strategy for hilar cholangiocarcinoma, with special reference to the limits of ductal resection in right-sided hepatectomies

The surgical anatomy of the hepatic hilar region is characterized by the three-dimensional formation of the branches of the bile duct, portal vein, and hepatic artery. The limit of ductal resection in hepatectomy for hilar cholangiocarcinoma is the most peripheral point where the hepatic ducts can be separated from the vasculature. The limit is different for each type of hepatectomy because the portal vein branches that should be preserved or divided vary with the extent of the hepatectomy, and therefore the limit of separation of the hepatic ducts differs. Surgeons are required to understand the surgical anatomy and to identify the precise area of cancer spread on a preoperative cholangiogram so as to choose the appropriate type of hepatectomy, and to ensure that the remnant ductal margin is cancer-negative.

Laparoscopic modified Devine exclusion gastrojejunostomy as a palliative surgery to relieve malignant pyloroduodenal obstruction by unresectable cancer

BACKGROUND

Malignant pyloroduodenal obstruction by an unresectable cancer makes ingesting food or liquids impossible for patients. The patient's quality of life deteriorates rapidly, leading to a dismal prognosis. The modified Devine exclusion (MDE) method of open laparotomy has been reported to be effective in such cases.

METHODS

We performed laparoscopic MDE gastrojejunostomy in 8 cases. The patient data collected included surgical time, morbidity and mortality, length of stay, the state and duration of adequate oral ingestion, and outcome.

RESULTS

The median surgical time was 191 minutes. There were no complications postoperatively. The median postoperative stay was 7 days. In that time, feeding conditions were restored to pre-illness levels. All patients were palliated successfully using this procedure.

CONCLUSIONS

Laparoscopic MDE gastrojejunostomy allows patients to regain their ability to eat, significantly improving their quality of life. This alternative laparoscopic procedure is effective for patients whose prognosis is poor as a result of unresectable cancer.

Distal pancreatectomy with en bloc celiac axis resection for locally advanced pancreatic body cancer: long-term results

OBJECTIVE

To analyze the long-term results of distal pancreatectomy with en bloc celiac axis resection (DP-CAR), a newly designed extended surgical procedure for locally advanced cancer of the pancreatic body.

SUMMARY BACKGROUND DATA

Pancreatic body cancer often involves the common hepatic artery and/or the celiac axis and is regarded as an unresectable disease. We previously reported the feasibility and safety of DP-CAR in 10 patients and 3 preliminary cases; however, the long-term results are unknown.

METHODS

Between May 1998 and September 2005, 23 patients underwent DP-CAR. No reconstruction of the arterial system was required because of early development of the collateral arterial pathways via the pancreatoduodenal arcades from the superior mesenteric artery. We routinely used preoperative coil embolization of the common hepatic artery to enlarge the collateral pathways.

RESULTS

The postoperative mortality rate was 0%, despite a high morbidity rate (48%). The chief postoperative complications were pancreatic fistula and ischemic gastropathy. Contrary to expectations, postoperative diarrhea was mild. Preoperative intractable abdominal and/or back pain in 10 patients was completely alleviated immediately after surgery. The surgical margins were histologically negative in 21 patients (91%). The estimated overall 1- and 5-year survival rates were 71% and 42%, respectively, and the median survival was 21.0 months. The sites of recurrence were the liver in 6 patients and local recurrence in 2.

CONCLUSIONS

DP-CAR offers a high R0 resectability rate and may potentially achieve complete local control in selected patients. The persisting early hepatic recurrence may indicate DP-CAR for the treatment of less advanced disease.

Feasibility of en-bloc wedge resection of the pancreas and/or the duodenum as an alternative to pancreatoduodenectomy for advanced gallbladder cancer

Pancreatoduodenectomy has been described as a possible treatment for gallbladder cancer that presents with evidence of direct invasion to the pancreas and/or the duodenum. This procedure does, however, carry a significantly higher morbidity and mortality if performed with a hepatectomy. An alternative procedure, therefore, of wedge resection of the invaded organ(s) was investigated in this study. On recognition of infiltration of the tumor into the pancreas and/or the duodenum, an en-bloc wedge resection of the organ(s) combined with the original tumor was the intended procedure. However, a pancreatoduodenectomy was performed if the tumor was not resectable by an attempted wedge resection. Operative and long-term outcomes were compared between patients who underwent wedge resection (n = 9) and pancreatoduodenectomy (n = 8). One patient in each group was incorrectly diagnosed preoperatively as having cancer invasion, as opposed to inflammatory changes, as recognized by subsequent histology. All tumors were excised with tumor-free pancreatic and duodenal margins. Postoperative complications occurred in one patient with wedge resection and four with pancreatoduodenectomy. One in-hospital death occurred in each group; one patient died with wedge resection of sepsis and one patient with pancreatoduodenectomy died of a pancreatic leak. No local recurrence occurred in either group. There was no difference in cumulative survival rates between the groups. Wedge resection was considered to be a feasible surgical procedure, in terms of morbidity, respectability, and long-term outcome.

Formation of bone-like apatite enhanced by hydrolysis of octacalcium phosphate crystals deposited in collagen matrix

It has been shown that granules of synthetic octacalcium phosphate (OCP) or the composites with collagen are capable of enhancing bone regeneration, accompanied by a gradual conversion from OCP to apatite with time. The present study was designed to investigate whether formation of bone-like apatite can be accelerated by OCP deposited throughout collagen matrix (OCP collagen complex, OCC) immersed in simulated body fluid (SBF). The formation of bone-like apatite has been suggested to be essential to induce osteoconductivity of various substrates. The formation of OCP in collagen solution was investigated in calcium or phosphate ions in the range between 22.5 and 142.5 mM and pH 6.26 and 8.56. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) showed that condition to nucleate OCP was limited to that of a solution with Ca/P 0.43 around pH 7.16 in the presence of collagen. OCP was shown to be formed throughout the collagen matrix by SEM observation. The immersion of OCC in SBF up to 10 days enhanced apatite crystal deposition, probably through OCP-apatite conversion: the apatite formation in OCC took place within only 1 day. The present study indicated that the existence of OCP deposited throughout the collagen matrix promotes bone-like apatite formation under physiological condition.

Laparoscopic two-stage surgery for goblet cell carcinoid of the appendix: report of a case and review of the Japanese literature

Goblet cell carcinoid of the appendix is a rare clinical entity exhibiting features of both carcinoid and adenocarcinoma. Here, we present the first report of laparoscopic 2-stage surgery for goblet cell carcinoid with a review of the Japanese literature. A 49-year-old man underwent laparoscopic appendectomy under the diagnosis of acute appendicitis. A pathologic diagnosis of goblet cell carcinoid, accompanied by the aggressive proliferation, with acute appendicitis was made. Subsequent laparoscopic ileocecal resection was performed, and it was verified that there were neither residual tumor nor lymph node metastases. The postoperative course was uneventful. Because goblet cell carcinoid may be difficult to clinically distinguish from acute appendicitis, pathologic examination is essential. Depending upon the grade of tumor proliferation, additional resection should be considered, and our experience with this case suggests that laparoscopic 2-stage surgery is feasible for the adequate treatment of goblet cell carcinoid without complications.

Number of Lymph Node Metastases Is Better Predictor of Prognosis Than Level of Lymph Node Metastasis in Patients with Node-Positive Colon Cancer

BACKGROUND

Lymph node metastasis is the most important prognostic factor for colon cancer patients. Survival is also related to the number and level of positive lymph nodes (PLNs). Definitions of degree of PLNs for colon cancer differ greatly between the number and level of PLNs.

STUDY DESIGN

The aim of this study is to compare number and level of PLNs to see which is a better predictor of prognosis for node-positive colon cancer. One hundred eighteen patients underwent histologically curative resection for node-positive colon cancer. We calculated the cumulative 5-year survival rates and examined prognostic factors for multivariate analysis based on the number and level of PLNs and additional factors. The number of PLNs was classified as either one to three PLNs or more than four PLNs, and level of PLNs was classified as either Level I (pericolic lymph node metastasis) or Level II (lymph node metastasis along the major named vessel supplying the tumor, and that around the origin of a main artery).

RESULTS

Cumulative 5-year survival rates were statistically different between the 1 to 3 PLNs group and the more than 4 PLNs group, but not significantly different between Level I group and Level II group. Multivariate analysis showed that number, not level, of PLNs was an independent prognostic factor.

CONCLUSIONS

In node-positive colon cancer, number of PLNs predicted prognosis better than level of PLNs.

Characterization of dentin formed in transplanted rat molars by electron probe microanalysis

The present study was designed to characterize dentin formed in transplanted rat molars by investigating calcium (Ca), phosphorus (P), and magnesium (Mg) concentrations using electron probe microanalysis (EPMA) as well as examining the rate of dentin matrix formation by vital staining. The unerupted immature lower right second molar in 2-week-old rats was transplanted into the upper right first molar socket. Rats were injected with oxytetracycline, calcein, and alizarin intraperitoneally at 1 day before and 1 and 2 weeks after transplantation, respectively, for vital staining. The maxillae and mandibles were fixed 3 weeks after transplantation, resected, and embedded in resin. Undemineralized sections were cut and examined by fluorescent microscopy and EPMA. The thickness of dentin formed in the first week after transplantation was significantly less than that of dentin formed in any other 1-week period in the transplanted tooth and was about one-fifth the thickness of dentin formed in control teeth. Formation of dentin recovered in the third week after transplantation. In the first week after transplantation, EPMA demonstrated a sharp increase in Mg concentration with a slight decrease in Ca concentration. Thereafter, no significant difference was identified among Ca, P, or Mg concentrations or the Ca/P ratio between transplanted and control teeth. These results suggest that disruption of the circulation and innervation by transplantation cause a temporary change in the matrix formation rate and elemental distribution of dentin, which is subsequently restored within 2 weeks after transplantation.

Comparative study on osteoconductivity by synthetic octacalcium phosphate and sintered hydroxyapatite in rabbit bone marrow

Octacalcium phosphate (OCP) is thought to be a precursor of the mineral crystals in biological apatite. Synthetic OCP has been shown to be converted into an apatite structure when implanted in murine calvarial bone, to enhance bone regeneration more than synthetic hydroxyapatite (HA), and to degrade faster than biodegradable beta-tricalcium phosphate. This study was designed to investigate whether OCP implantation enhances the formation and resorption of new bone (remodeling) concomitant with OCP degradation when implanted intramedullary in a rabbit femur for 12 weeks, compared to sintered HA ceramic. Histological and histomorphometric analyses using undecalcified specimens showed that the area of bone apposition was significantly higher on OCP than on HA between 2 and 3 weeks, whereas it subsequently became smaller on OCP than on HA. The area attacked by multinucleated giant cells, including tartrate-resistant acid phosphatase (TRAP)-positive cells, was significantly higher for OCP than for HA at 8 weeks. Radiography revealed resorption of OCP but not of HA. The results disclose some osteoconductive characteristics of synthetic OCP in the bone marrow space: (1) enhancement of bone regeneration at the initial bone apposition stage and (2) stimulation of resorption of the newly formed bone coupled with OCP biodegradation mediated by TRAP-positive osteoclast-like cells. These results suggest that synthetic OCP would be a more useful bone substitute than HA in implant applications where rapid bone formation and concomitant implant resorption are important considerations.