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Biomedical subjects

Yutaka Atomi

Publications and source records attributed to Yutaka Atomi.

At least 19 recordsLinked to original sources
PubMed2006

Effect of a selective thromboxane A2 synthetase inhibitor on the systemic changes induced by circulating pancreatic phospholipase A2.

BACKGROUND: In acute pancreatitis, pancreatic phospholipase A(2) (PLA2) in the circulating blood hydrolyzes phospholipids contained in plasma lipoproteins, liberating eicosanoid precursors that are subsequently converted to various eicosanoids. The pathophysiological significance of eicosanoid synthesis via this pathway is unknown. The aim of this study was to clarify the role of thromboxane A(2) (TXA(2)) synthesis by circulating pancreatic PLA(2) in the pathogenesis of the systemic complications of acute pancreatitis. METHODS: Guinea pigs were divided into two groups: a control group and an ozagrel group, which received intravenous administration of ozagrel, a selective TXA(2) synthetase inhibitor. Pancreatic PLA(2) was infused intravenously in both groups for 30 min, and systemic changes during the infusion were examined. RESULTS: In the control group, there was an increase in plasma thromboxane B(2) (TXB(2)) concentration, a decrease in mean arterial pressure and heart rate, a decrease in arterial base excess (BE), bicarbonate concentration (HCO(3) (-)), and pH, a decrease in platelet count and plasma fibrinogen concentration, and a shortened prothrombin time during the infusion of pancreatic PLA(2). In the ozagrel-treated group, changes in plasma TXB(2) concentration, BE, HCO(3) (-), and platelet count were significantly inhibited. CONCLUSIONS: TXA(2) synthesis by circulating pancreatic PLA(2) contributes to metabolic acidosis and thrombocytopenia during acute pancreatitis.

Acute Disease↗
PubMed2006

Preoperative endoscopic pancreatic stenting for prophylaxis of pancreatic fistula development after distal pancreatectomy.

BACKGROUND AND OBJECTIVE: Pancreatic fistula is a common complication of distal pancreatectomy (DP). Although various surgical procedures have been proposed for DP in an attempt to decrease the high incidence of pancreatic fistula, the prevention of pancreatic fistula remains a major problem in DP. Endoscopic pancreatic stenting for the treatment or prophylaxis of such a fistula has been rarely described. METHODS: We reviewed 9 patients who underwent preoperative endoscopic pancreatic stenting for the prophylaxis of pancreatic fistula development after DP. RESULTS: Preoperative endoscopic pancreatic stenting was successfully performed with a 7F stent in all the 9 patients. Two patients, both with intraductal papillary mucinous tumor, developed mild acute pancreatitis after the stent placement. None of the 9 patients developed pancreatic fistula. The pancreatic stent was removed from 8 to 28 days (mean 11 days) postoperatively. CONCLUSIONS: Preoperative endoscopic pancreatic stenting may be an effective prophylactic measure against pancreatic fistula development following DP in selected patients.

Adenocarcinoma, Mucinous↗
PubMed2006

Anatomic study of the superior right colic vein: its relevance to pancreatic and colonic surgery.

BACKGROUND: This study was designed to describe the precise anatomic venous tributaries of the superior mesenteric vein with special emphasis on the superior right colic vein (SRCV), which is seldom mentioned in the literature. METHODS: Nine adult cadavers were dissected to define the venous tributaries of the superior mesenteric vein. The SRCV, middle colic vein, and right colic vein (RCV) were defined as those that drained from the marginal vein of the right flexure of the colon, the transverse colon, and the ascending colon, respectively. RESULTS: The SRCV was observed to drain from the right flexure of the colon to the confluence of the right gastroepiploic and superior pancreaticoduodenal veins and present the gastrocolic trunk of Henle (GTH) in 8 of 9 cases. The RCV terminated into the GTH in 4 cases. The SRCV, the RCV, and the middle colic vein formed a confluence and entered into the GTH in 1 case. CONCLUSIONS: The SRCV exits and drains from the right colonic flexure to the GTH in 89% of cases.

Adult↗
PubMed2006

Gallstone disease: Management of intrahepatic stones.

Hepatolithiasis (oriental cholangiohepatitis) has reportedly been endemic only in East Asia. The disease is now occasionally recognized in Western societies, especially in people who have lived in the Orient. Hepatolithiasis is characterized by its intractable nature and frequent recurrence, requiring multiple operative interventions, which is in distinct contrast to gallbladder stones. In addition to frequent cholangitis and chronic sepsis, it is widely known that longstanding intrahepatic stones lead to intrahepatic cholangiocarcinoma. Symptoms of hepatolithiasis include abdominal pain, jaundice and cholangitis. Pyogenic cholangitis due to strictures and hepatolithiasis tends to recur, and sometimes patients may present with liver abscesses. Radiological studies and percutaneous procedures are keys in the diagnosis and treatment of hepatolithiasis. Non-invasive imaging modalities such as ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) accurately depict the normal anatomy and presence of intrahepatic stones. It should be stressed that each modality has its pros and cons, and imaging studies should be performed on the basis of understanding the pathophysiology. As the diagnostic role of magnetic resonance cholangiopancreatography (MRCP) evolves, the roles of both endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC), and their most significant advantage, is primarily therapeutic with their ability to extract stones, biopsy intraductal lesions, and place stents easily. The primary goals of treatment are to eliminate attacks of cholangitis and to stop the progression of the disease (which leads to biliary cirrhosis). Surgery has a primary role in hepatolithiasis because hepatolithiasis tends to recur, so that multiple sessions of the endoscopic approach (i.e. two or three times a year) are often required. PTC is an alternative when surgical resection of the affected lobe is difficult. Techniques for lithotripsy, including shockwave and laser, can be applied in endoscopic sessions, offering a better chance of clearing the stones.

Bile Ducts, Intrahepatic↗
PubMed2006

Distribution of lymphatic vessels in the neural plexuses surrounding the superior mesenteric artery.

OBJECTIVES: To investigate whether lymphatic vessels exist in the neural plexuses surrounding the superior mesenteric artery (SMA) and the ultrastructural relationship between neural plexuses and lymphatic vessels. METHODS: A total of 970 serial sections including the structure surrounding the SMA were obtained from 9 cadavers. They were subjected to conventional hematoxylin/eosin staining and immunostaining for the lymphatic marker D2-40. Epithelial membrane antigen and S100 were also immunostained to identify the perineurium and nerve bundles, respectively. RESULTS: Thin-walled, erythrocyte-free vessels staining with lymphatic markers (D2-40) were found in the neural plexuses surrounding the SMA along a full circumference. There seemed to be a distribution correlation between lymphatic vessels and neural plexuses. Lymphatic vessels were not identified within the nerve bundles. The plexuses contained no lymph nodes in any sections. CONCLUSIONS: To our knowledge we report the immunohistochemical visualization of lymphatic vessels in peri-SMA neural plexuses for the first time. Therefore, particular attention should be paid to the lymphatic vessels within neural plexuses as a possible route of invasion and the source of pancreatic cancer recurrence.

Aged↗
PubMed2006

Actual number of tumor budding as a new tool for the individualization of treatment of T1 colorectal carcinomas.

BACKGROUND AND AIM: Treatment of T1 colorectal carcinomas, either local excision including endoscopic polypectomy or radical surgery, has always been problematic in everyday practice. Although previous studies have revealed that tumor budding at the invasive margin can be a marker for the malignant potential of T1 colorectal carcinomas, the evaluation of tumor budding has not been standardized as yet. In the present study, we attempted to apply the actual number of tumor budding units for the individualization of treatment in T1 colorectal carcinomas. METHODS: In 76 T1 colorectal carcinomas, associations between lymph node metastasis and clinicopathological parameters were examined statistically. A mathematical formula for predicting the risk of lymph node metastasis was constructed and decision analysis was attempted to determine individually the indication for additional surgery after endoscopic mucosal resection of T1 colorectal carcinomas. RESULTS: Of the clinicopathological parameters examined, multivariate analysis showed that the actual number of tumor budding units alone was significantly associated with lymph node metastasis. The probability of lymph node metastasis was calculated as Z = 0.07 x (budding counts) - 3.726, probability = 1/1 + e(-Z). The more the budding counts, the higher the probability of lymph node metastasis. This formula was able to accurately predict lymph node metastasis in successive cases. The actual number of tumor budding units can be applied to decision analysis in determining an indication for additional surgery after endoscopic mucosal resection of T1 colorectal carcinomas. CONCLUSIONS: The actual number of tumor budding units may be useful in the decision making for patient-oriented treatment of T1 colorectal carcinomas.

Adult↗
PubMed2006

Pancreatic carcinoma that completely obstructs the Wirsung duct without dilatation of the main pancreatic duct.

BACKGROUND AND AIM: Pancreatic carcinomas in which the main pancreatic duct (MPD) is completely obstructed are almost always associated with dilatation of the upstream MPD. However, some carcinomas are not associated with MPD dilatation despite complete MPD obstruction. This paradoxical phenomenon has not been well documented. METHODS: The findings from endoscopic retrograde cholangiopancreatography in 207 cases of pancreatic head carcinomas were analyzed with special reference to this unique type of carcinoma. Twenty-five of the patients were found to exhibit no MPD dilatation on ultrasonography, computed tomography or magnetic resonance imaging. RESULTS: Pancreatography via the major papilla showed complete obstruction of the MPD (112 patients with MPD dilatation and 6 without), stenosis (70 and 10, respectively), or no abnormal findings (0 and 9, respectively). In all six patients with complete MPD obstruction but without upstream MPD dilatation, injection of the minor papilla revealed a non-dilated dorsal pancreatic duct. The size of the obstructive carcinomas with and without MPD dilatation was comparable. CONCLUSIONS: Some (3%) pancreatic head carcinomas are not associated with MPD dilatation despite complete obstruction of the Wirsung duct. In such cases, the Santorini duct drains the dorsal pancreatic duct, completely compensating for the obstructed Wirsung duct. Attention should be paid to this unique type of carcinoma in diagnosing pancreatic head carcinomas.

Adenocarcinoma↗
PubMed2006

A gene encoding a family with sequence similarity 84, member A (FAM84A) enhanced migration of human colon cancer cells.

Using genome-wide cDNA microarray analysis, we identified a number of genes whose expression was up-regulated frequently in colorectal cancer. One of these was a gene termed FAM84A that was not expressed in any of the 23 normal tissues examined except the testis. Although immuno-cytochemical staining revealed localization of FAM84A protein in the subcellular membrane region, the staining was limited to the region lacking attachment with neighboring cells. In addition, we found that exogenous FAM84A expression increased cell motility in NIH3T3 cells, and that phosphorylation of serine 38 of FAM84A was associated with morphology of cells. Our results indicate a possibility that up-regulation of FAM84A plays a critical role in progression of colon cancer.

Animals↗
PubMed2005

Tumor budding and evidence-based treatment of T2 rectal carcinomas.

BACKGROUND: The validity of the histological criteria in deciding additional bowel resection after local excision of T2 rectal carcinomas is questioned. METHODOLOGY: In 72 T2 colorectal carcinomas resected by major surgery, the associations between lymph node metastasis (LNM) and clinicopathologic parameters were examined statistically, a prediction formula for LNM was constructed and decision analysis was attempted. RESULTS: Multivariate analysis showed that female gender and a greater number of tumor budding were significantly associated with LNM. The probability of LNM can be calculated as follows; Z = 0.037 x (budding number) + 2.08 x (SEX; male, 1; female, 2) - 5.736; Probability = 1/1 + e(-Z). When a 75-year-old patient has pulmonary complications, the operative risk is assumed to be over 2%. If a number of tumor budding is 0, the risk of LNM is calculated as 2.4% in a male and 17.1% in a female patient. On the assumption that the risk of liver metastasis is half of that of LNM, and the salvageabilities after LNM and liver metastasis are 20% and 50%, respectively, observation policy is justified for a male patient, whereas additional surgery should be undertaken for a female patient. CONCLUSIONS: A number of tumor budding may be useful for determining the individualized treatment of T2 rectal carcinomas.

Cell Differentiation↗
PubMed2005

Impact of lateral pelvic lymph node dissection on evacuatory and urinary functions following low anterior resection for advanced rectal carcinoma.

BACKGROUND AND AIM: Lateral pelvic lymph node dissection (LPLD) has been reported to be beneficial in terms of survival for locally advanced low rectal carcinoma. However, the impact of LPLD on bowel function has not yet been determined by means of anorectal physiologic investigation. PATIENTS AND METHODS: Fifty-seven rectal cancer patients who underwent low anterior resection were evaluated with clinical and physiologic parameters. Of these, 15 patients had LPLD. The postoperative bowel and urinary function were evaluated with patients' questionnaire and anorectal manometry before and after the operation. RESULTS: The proportion of patients who had pouch reconstruction, adjuvant radiation therapy, and autonomic nerve dissection were significantly higher in the LPLD group. The incidence of evacuatory dysfunction was significantly higher (80% vs 45%) postoperatively in the LPLD group. There was no significant difference in anal sphincter pressures, sensory threshold, and neorectal volumes between the groups postoperatively. In terms of urinary function, use of medication for urination was significantly frequent in the LPLD group. Multivariate analysis identified the level of anastomosis as an independent affecting factor for evacuatory dysfunction and LPLD for urinary dysfunction. CONCLUSION: Although LPLD affected urinary dysfunction, it did not impair postoperative evacuatory function in the early postoperative period.

Adult↗
PubMed2005

Laparoscopic pancreatic surgery.

In the past, in the pancreas, a minimally invasive technique was only used for diagnostic laparoscopy in evaluating periampullary malignancy. Recent advances in operative techniques and instrumentation have empowered surgeons to perform virtually all procedures in the pancreas, including the Whipple procedure. Some of these procedures represent the most sophisticated application of minimally invasive surgery, and their outcomes are reportedly better than those of conventional open approaches. In addition to the evaluation of resectability in periampullary malignancy, palliative procedures, including biliary bypasses and gastrojejunostomy, can be performed laparoscopically. Although it is reportedly feasible to perform a Whipple procedure laparescopically, no benefit of the laparoscopic approach over the conventional open approach has been documented. Laparoscopic distal pancreatectomy, with or without preserving the spleen, is technically easier than the Whipple procedure, and is more widely accepted. Indications for laparoscopic distal pancreatectomy include cystic neoplasms and islet-cell tumors located in the pancreatic body or tail. Complications of acute and chronic pancreatitis may be treated with the use of surgical laparoscopy. When infected necrotizing pancreatitis is identified, surgical intervention for drainage and debridement is required. According to the type and location of infected necrotizing pancreatitis, three laparoscopic operative approaches have been reported: infracolic debridement, retroperitoneal debridement, and laparoscopic transgastric pancreatic necrosectomy. When internal drainage is indicated for a pseudocyst, a minimally invasive technique is a promising option. Laparoscopic pseudocyst gastrostomy, cyst jejunostomy, or cyst duodenostomy can be performed, depending on the size and location of the pseudocyst. Especially when a pseudocyst is located in close contact with the posterior wall of the stomach, it is best drained by a pseudocyst gastrostomy, which can also be done with the use of an intragastric operative technique.

Debridement↗
PubMed2005

Effects of granulocyte colony-stimulating factor on neutrophils and inflammatory cytokines in the early stage of severe acute pancreatitis in rats.

BACKGROUND: The high mortality rate of severe acute pancreatitis (SAP) is closely associated with secondary infections of pancreatic and peripancreatic tissues. It was reported that granulocyte colony-stimulating factor (G-CSF) increased the number of leukocytes and enhanced their functions. However, an inflammatory response may be enhanced by an increased number of leukocytes. Our purpose was to study the roles of G-CSF in peritoneal-exudate neutrophils and inflammatory cytokines in the early stage of experimental SAP. METHODS: SAP was induced by injecting 0.2 ml of 3% taurocholate acid into the biliopancreatic duct in male Wistar rats. G-CSF (90 microg/kg body weight) or saline was administered 1 h before the SAP induction. The number of neutrophils and their phagocytic and bactericidal activities were evaluated, and the concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-1beta in plasma and ascitic fluid were measured 1 h and 3 h after the SAP induction. RESULTS: The number of peritoneal-exudate neutrophils (PENs) at 3 h was increased by G-CSF administration (81 +/- 50 x 10(5) cells/total exudate), as compared with that shown with saline administration (28 +/- 13 x 10(5) cells/total exudate; P < 0.05). The numbers of phagocytic and bactericidal neutrophils were also elevated by G-CSF administration. G-CSF administration did not increase the concentrations of TNF-alpha, IL-6, and IL-1beta in the plasma and ascitic fluid. CONCLUSIONS: G-CSF increases the numbers of neutrophils and enhances their functions against bacteria, but it does not enhance intraabdominal and systemic inflammatory responses in the early stage of SAP.

Animals↗
PubMed2005

Anorectal malignant melanoma: preoperative usefulness of magnetic resonance imaging.

Magnetic resonance imaging (MRI) findings in three patients with primary anorectal malignant melanoma are described. Two patients had melanotic and one had amelanotic anorectal melanoma. The findings of MRI with a pelvic coil and an endorectal coil were consistent with pathologic findings. MRI with a pelvic coil demonstrated the melanotic component as high signal intensity on T1-weighted imaging. MRI with a pelvic coil and an endorectal coil was useful for staging anorectal melanoma. This article describes the initial report of the use of an endorectal coil for malignant melanoma of the anorectum.

Adult↗
PubMed2005

Laparoscopic lymph node dissection after endoscopic submucosal dissection: a novel and minimally invasive approach to treating early-stage gastric cancer.

BACKGROUND AND OBJECTIVE: Endoscopic submucosal dissection (ESD), a newly developed endoscopic mucosal resection (EMR) technique, can completely cure a differentiated mucosal gastric cancer smaller than 2 cm. For early-stage gastric cancers (EGCs) deviating from the above-mentioned criterion, gastrectomy with lymph node dissection is performed for potential risk of lymph node metastasis (LNM). However, many of surgical EGC cases actually do not have LNM, indicating this surgery may not be necessary for many cases of EGC. To avoid this unnecessary surgery, we have introduced laparoscopic lymph node dissection (LLND) after ESD. Standard gastrectomy with extended lymph node dissection is indicated for patients if LLND reveals LNM. We present our novel approach and the preliminary results of EGC patients having potential risk of LNM. METHODS: Five patients with EGC deviating from the EMR criterion underwent the combination of ESD and LLND. ESD was performed using a newly developed insulation-tipped diathermic knife. Lymph nodes, which were determined on the basis of the location of the primary tumor and lymphatic drainage of the stomach, were removed laparoscopically. The lymphatic drainage was visualized by submucosally injecting indocyanine green (ICG) around the post-ESD ulcerative scars during intraoperative gastroscopy. RESULTS: The ESD enabled en bloc resection without any complications. The resected margins of all the lesions were free of cancer cells vertically and horizontally. LLND was successfully performed without any complications. The mean number of the dissected lymph nodes was 15 (range 6 to 22). In 4 of the 5 patients, the dissected lymph nodes were free of cancer cells, and therefore, the combination of ESD and LLND was considered a definitive treatment. The remaining patient was found to have LNM but chose not to undergo any surgery. During follow-ups, the patients' previous quality of life was restored without any tumor recurrence. CONCLUSIONS: The combination of ESD and LLND enables the complete resection of the primary tumor and the histologic determination of lymph node status. This combination treatment is a potential, minimally invasive method, and may obviate unnecessary gastrectomy without compromising curability for EGC patients having the potential risk of LNM.

Aged↗