Biomedical subjects

N Hayakawa

Publications and source records attributed to N Hayakawa.

At least 55 records · Page 3Linked to original sources

PubMed1999

Percutaneous transheptic cholangioscopic ethanol injection for intrabiliary tumor thrombi due to hepatocellular carcinoma.

Interventional treatments such as transcatheter arterial embolization and placement of a biliary endoprosthesis have been carried out in cases of inoperable hepatobiliary malignancy. We report here a case of recurrent intrabiliary tumor thrombi due to hepatocellular carcinoma, successfully treated by cholangioscopic ethanol injection in which the intrabiliary tumor thrombi were completely eliminated.

Bile Duct Neoplasms↗

PubMed1999

High incidence of meningioma among Hiroshima atomic bomb survivors.

Since the atomic bomb explosions in Hiroshima and Nagasaki, high incidences of leukemia, thyroid cancer and other tumors have been reported as atomic bomb-induced tumors. We investigated the incidence of meningioma among Hiroshima atomic bomb survivors. Sixty-eight patients surgically treated for meningioma who had been within 2.0 km of the hypocenter of the explosion were identified. Six hundred and seven non-exposed patients with meningioma were also studied. Treatment dates were from 1975 to 1992. The incidences of meningioma among 68 subjects within 2.0 km and 607 non-exposed patients were 8.7 and 3.0 cases per 10(5) persons per year, respectively. The incidences of meningioma among the survivors of Hiroshima in 5-year intervals since 1975 were 5.3, 7.4, 10.1, and 14.9, respectively. The incidences of meningioma classified by distances from the hypocenter of 1.5-2.0 km, 1.0-1.5 km and less than 1.0 km were 6.3, 7.6 and 20.0, respectively. The incidences of meningioma classified by doses to the brain of 0-0.099 Sv, 0.1-0.99 Sv and more than 1.0 Sv were 7.7, 9.2 and 18.2, respectively. The incidence of meningioma among Hiroshima atomic bomb survivors has increased since 1975. There was a significant correlation between the incidence and the dose of radiation to the brain. The present findings strongly suggest that meningioma is one of the tumors induced by atomic bombing in Hiroshima.

Brain↗

PubMed1999

Glucose transporter 2 concentrations in hyper- and hypothyroid rat livers.

The deterioration of glucose metabolism frequently observed in hyperthyroidism may be due in part to increased gluconeogenesis in the liver and glucose efflux through hepatocyte plasma membranes. Glucose transporter 2 (GLUT 2), a facilitative glucose transporter localized to the liver and pancreas, may play a role in this distorted glucose metabolism. We examined changes in the levels of GLUT 2 in livers from rats with l-thyroxine-induced hyperthyroidism or methimazole-induced hypothyroidism by using Western blotting to detect GLUT 2. An oral glucose tolerance test revealed an oxyhyperglycemic curve (impaired glucose tolerance) in hyperthyroid rats (n=7) and a flattened curve in hypothyroid rats (n=7). GLUT 2 levels in hepatocyte plasma membranes were significantly increased in hyperthyroid rats and were not decreased in hypothyroid rats compared with euthyroid rats. The same results were obtained with a densitometric assay. These findings suggest that changes in the liver GLUT 2 concentration may contribute to abnormal glucose metabolism in thyroid disorders.

Animals↗

PubMed1999

[Treatment of recurrent cancer after surgery for biliary malignancies].

Our strategy for recurrent tumor after surgical resection for biliary malignancies, especially for hilar cholangiocarcinoma, is described. One hundred and thirty-three patients with hilar cholangiocarcinoma underwent curative resection in our department until November, 1998, and recurrent carcinomas have been pointed out in 73 patients (54.9%). The site of recurrence was peritoneum (21 cases), liver (16 cases), pre-caval and retro-duodenal space (15 cases), hepatic hilum (11 cases), lymph node (9 cases), bone (6 cases), sinus tract of percutaneous transhepatic biliary drainage (PTBD) (5 cases) and so on. Surgical resection was applied to recurrent carcinomas after careful evaluation, and 9 patients underwent surgical resection of the recurrent tumor: sinus tract of PTBD in the abdominal and/or chest wall (4 cases), lymph node (2 cases), liver (1 case), hepaticojejunostomy (1 case) and duodenum (1 case). There were three hospital death patients. Other six patients survived for 16 months on an average (11-20 months) after surgery for recurrent tumor. PTBD for recurrent cancer at the hepatic hilum and gastrojejunostomy for local recurrence around the duodenum improved quality of life of patients. Radiation therapy for bone metastasis or local recurrence at the hepatic hilum was sometimes very effective. Effect of systemic or transarterial chemotherapy is still unknown.

Adult↗

PubMed1999

Enhanced expression of inducible nitric oxide synthase and nitrotyrosine in gastric mucosa of gastric cancer patients.

Recent studies (K. Komoto et al., Am. J. Gastroenterol., 93: 1271-1276, 1998) have shown that Helicobacter pylori infection is associated with gastric cancer. However, the mechanism of H. pylori in carcinogenesis has not been clarified. H. pylori infection leads to a sustained production of reactive nitrogen species that may contribute to cause DNA damage. In this study, we examined the expression of inducible nitric oxide synthase (iNOS) and nitrotyrosine in gastric mucosa. The expression of iNOS and nitrotyrosine was examined by immunohistochemistry in 93 patients who initially underwent gastric biopsies between 1975 and 1992. Thirty-four individuals were later found to have gastric cancer at least 2 years after the initial biopsies (group A). The other 59 subjects have shown no evidence of gastric cancer during long-term follow-up. Fifty-one of these patients were positive for H. pylori (group B), and eight were negative for H. pylori (group C). The expression of iNOS and nitrotyrosine in the gastric mucosa was significantly higher in H. pylori-positive groups A and B than in H. pylori-negative group C. Among the H. pylori-positive patients, the expression of iNOS and nitrotyrosine was significantly higher in group A than in group B. These results suggest that high production of iNOS and nitrotyrosine in the gastric mucosa infected with H. pylori may contribute to the carcinogenesis of gastric cancer.

Adult↗

PubMed1998

Effects of thyroid hormone on the sorbitol pathway in streptozotocin-induced diabetic rats.

Sorbitol accumulation plays an important role in diabetic complications involving the kidney, nerves, retina, lens and cardiac muscle. To investigate the influence of thyroid hormone on the sorbitol pathway, we studied the effects of thyroid hormone on polyol metabolism in normal and diabetic rats. Rats were divided into three groups: controls, streptozotocin (STZ)-induced diabetic euthyroid rats (DM) and STZ-induced diabetic hyperthyroid (thyroxine-injected) rats (DM+HT). The sorbitol (Sor) concentrations in the kidney, liver and sciatic nerve (2.53+/-0.74, 0.97+/-0.16 and 24.0+/-5.1 nmol/mg protein, respectively) of the DM rats were significantly higher than those (1.48+/-0.31, 0.58+/-0.13 and 3. 1+/-0.6 nmol/mg protein) of the control rats. The Sor concentrations in the kidney and sciatic nerve of the DM+HT rats (1.26+/-0.29 and 9. 40+/-1.2 nmol/mg protein) were significantly lower than those in the DM rats. These values were reduced in the liver, unchanged in the kidney, and increased in the sciatic nerve from the hyperthyroid rats without diabetes. Thyroid hormone reduced the aldose reductase (AR) activities in the kidney, liver and sciatic nerve of the DM rats, and similarly reduced AR in the kidney and liver, but not in the sciatic nerve, of the non-diabetic rats. The sorbitol dehydrogenase (SDH) activities were decreased by thyroid hormone in the kidney and liver but not the sciatic nerve of DM rats. In the non-diabetic rats, this enzyme activity was decreased in liver, but not in kidney or sciatic nerve. A positive correlation between the Sor concentration and AR activity was observed in the kidney and liver but not in the sciatic nerve from control, DM and DM+HT rats. A negative correlation was observed between the Sor concentration and SDH activities in the same organs. These data suggest that thyroid hormone affects the sorbitol pathway, but the detailed mechanism whereby this hormone reduces the sorbitol content (especially in diabetic rats) remains to be clarified.

Aldehyde Reductase↗

PubMed1998

Change in telomerase activity of rat organs during growth and aging.

Telomerase activity is usually undetectable in adult human tissues, but is positive in embryonic tissues and in cancers. In rodents, however, several organs of normal adult animals express substantial amounts of telomerase activity. In this study, we observed the changes in the telomerase activity in rat organs during growth and aging and found that telomerase activity showed chronological patterns which were characteristic to organs. In lung and brain, the high telomerase activity of embryonic stage decreased rapidly after birth. In lymphoid tissues, telomerase activity increased after birth and reached to its maximum at 4 to 7 week. In liver, it stayed at nearly constant level throughout life. The telomerase activity in regenerating rat liver decreased temporally immediately after partial hepatectomy, then increased to a level that is higher than normal control. In contrast, it rapidly diminished in the occluded lobes after ligation of portal vein branch.

Aging↗

PubMed1998

Reduction of activity, but no decrease in concentration, of erythrocyte Cu,Zn-superoxide dismutase by hyperglycaemia in diabetic patients.

Cu,Zn-superoxide dismutase(SOD) activity in erythrocytes is affected by various diseases, including diabetes mellitus (DM). We investigated changes in the Cu,Zn-SOD activity compared to changes in the Cu,Zn-SOD concentration in erythrocytes obtained from patients with Type 2 (non-insulin-dependent) diabetes mellitus. Cu,Zn-SOD activity in erythrocytes was significantly lower in Type 2 DM patients than in healthy non-diabetic subjects. The activity correlated negatively with HbA1c, but not with other indicators of metabolic control, such as fasting blood glucose or plasma cholesterol or triglyceride. However, there was no statistically significant difference in erythrocyte concentration of Cu,Zn-SOD between diabetic and control samples. Concentration did not correlate with enzymatic activity or HbA1c. These findings indicate that the inactivation of Cu,Zn-SOD activity in erythrocytes of Type 2 DM patients by hyperglycaemia may be slow, because there is a negative correlation between the enzyme activities and HbA1c levels, but not fasting blood glucose levels. This is consistent with glycosylation of the active site of Cu,Zn-SOD, without any effect of hyperglycaemia on the concentration of Cu,Zn-SOD.

Adult↗

PubMed1998

A New Position for Photoplethysmography Assessment of Lower Leg Venous Function-Technical Notes.

A new position for photoplethysmographic (PPG) assessment of lower leg venous function is described and tested. This study aids in the selection of patients for more limited stripping operation. PPG measurements were carried out in the usual sitting position and in the supine body position on limbs with primary varicose veins. Competence of the greater saphenous vein (GSV) and incompetent perforators were evaluated by venography. Limbs with a competent GSV in the lower leg had a longer 50% venous refill time (VRT/2) in the supine body position than in the sitting position (7.6 +/- 0.6 seconds vs 5.0 +/- 0.4 seconds, p < 0.01). Limbs without incompetent perforators had a longer VRT/2 in the supine body position than in the sitting position (8.0 +/- 1.1 seconds vs 5.1 +/- 0.3 seconds, p < 0.05). PPG measurement in the supine body position gave a better separation of VRT/2s on GSV competence in the lower leg and incompetent perforators. The supine body position is recommended for assessing lower leg venous function.

Journal Article↗

PubMed1998

Aggressive surgical treatment of hilar cholangiocarcinoma.

Recent progress in surgical techniques for and the perioperative management of hilar cholangiocarcinoma has led to improved outcomes for aggressive liver and bile duct resections, which, however, still show considerable morbidity and mortality. In this article, the results of pioneers' attempts in hepatobiliary surgery for difficult hilar cholangiocarcinomas are reviewed. It is recommended that curative hepatobiliary resection should be performed for hilar cholangiocarcinoma, with careful preoperative management of patients complicated with several difficult conditions.

Bile Duct Neoplasms↗

PubMed1998

Right hepatic lobectomy and subsegmental resection of the left caudate lobe for gallbladder carcinoma involving the hepatic hilus: preservation of the ventral portion of the left caudate lobe.

A case of gallbladder carcinoma in a 75-year-old woman with familial hyperbilirubinemia and preoperative hepatic dysfunction is presented. Tube cholangiography through a percutaneous transhepatic biliary drainage (PTBD) catheter demonstrated a stricture and the hepatic confluence without filling of the gallbladder and showed two bile duct branches arising from the left caudate lobe. Cholangiography also disclosed that the left dorsal branch, which joined the right hepatic bile duct, was involved with tumor, while the left ventral branch, which joined the left hepatic duct, was not. Extended right hepatic lobectomy with resection of the dorsal portion of the left caudate lobe, preserving the ventral portion of the left caudate lobe, was performed. Postoperative cholangiography showed that the ventral branch of the left caudate lobe bile duct was preserved. Precise preoperative anatomic diagnosis of the biliary system in patients with hepatobiliary cancer allows successful subsegmental resection of the caudate lobe.

Aged↗

PubMed1998

Mucosal bile duct carcinoma with superficial spread.

We describe a case of mucosal bile duct carcinoma with superficial spread in a 69-year-old man with gallstone pancreatitis. The patient was seen at the hospital because of abdominal pain, fever, and jaundice. Endoscopic retrograde cholangiography (ERC) demonstrated a protruding lesion in the lower third of the common bile duct (CBD) showing wall irregularity suggestive of malignancy. Percutaneous transhepatic cholangioscopy (PTCS) disclosed a papillary tumor with granular mucosa extending continuously to the middle third of the CBD. Cholangioscopic biopsy specimens taken from both the papillary tumor and surrounding granular mucosa revealed papillary adenocarcinoma. After this assessment of extent of cancer by PTCS, we performed pancreatoduodenectomy with extrahepatic bile duct resection and regional lymph node dissection. Pathology examination revealed papillary adenocarcinoma limited to the mucosal layer. The resected margin of the bile duct was free of tumor. We also reviewed 25 cases of early mucosal bile duct carcinoma described in detail in the Japanese literature, and we discuss the diagnostic advantages of PTCS.

Adenocarcinoma, Papillary↗

PubMed1998

A paired wedge filter system for compensation in dose differences.

OBJECTIVE: In radiotherapy, it is important to conform the high dose volume to the planned target volume. A variable thickness paired wedge filter system was developed to compensate for dose inhomogeneity arising from field width segment variation in conformal irradiation. MATERIALS AND METHODS: The present study used a 6 MV linear accelerator equipped with multileaf collimator leaves and a paired wedge compensating filter system. The dose variation due to field width was measured in each field segment width. The variation in attenuation of the compensators was measured as a function of filter position. As the field width increases, the relative absorbed dose also increases; this is the point of requiring compensation, so it can be in reverse proportion. RESULTS: As the field width increases, the relative absorbed dose also increases; this is why compensation is required and thus it must be in reverse proportion. Attenuation of the absorbed dose by the paired filters was in proportion to the filter position. The filter position to compensate for the difference of absorbed doses was defined by the square root of the field width. For a field varying in width from 4 to 16 cm, the variation in the absorbed dose across the field was reduced from 12% to 2.7%. CONCLUSION: This paired wedge filter system reduced absorbed dose variations across multileaf collimator shaped fields and can facilitate treatment planning in conformal therapy.

Humans↗

PubMed1998

Different gastric emptying of solid and liquid meals after pylorus-preserving pancreatoduodenectomy.

BACKGROUND: Transient gastric stasis immediately after pylorus-preserving pancreatoduodenectomy (PPPD) is a common complication, but the cause remains unknown. Changes in gastric emptying were investigated in patients undergoing PPPD for periampullary malignancy. METHODS: In 14 patients undergoing PPPD, liquid- and solid-phase gastric emptying were evaluated before and after operation (mean 38 (range 27-53) days after operation). Two pharmacological gastric-emptying tests were used: the acetaminophen test for liquid-phase emptying and the sulphamethizole capsule food test for solid-phase gastric emptying. RESULTS: All patients exhibited delayed solid emptying but fairly good liquid emptying. CONCLUSION: Gastric function in the early postoperative period after PPPD is characterized by delayed solid-phase but good liquid-phase emptying.

Acetaminophen↗

PubMed1998

Surface expression and release of soluble forms of CD8 and CD23 in CD40- and IL-4-activated mononuclear cells from patients with Graves' disease (GD).

We investigated the effect of T cell-dependent B cell activation on the surface expression and release of the soluble forms of CD8 and CD23 by peripheral blood mononuclear cells (PBMC) obtained from patients with GD, versus patients with Hashimoto's thyroiditis, and normal controls. Incubating the PBMC with anti-CD40 MoAbs and IL-4 increased the soluble CD23 levels in cells from all three groups. An increase in the number of CD23+ cells was observed in the PBMC from the patients with GD, but not in PBMC from Hashimoto's thyroiditis or controls. Less soluble CD8 was released from anti-CD40 antibody and IL-4-stimulated PBMC obtained from patients with GD relative to those from the controls. In addition, the number of CD8+ cells was significantly reduced in stimulated PBMC from the GD patients relative to those from controls. Incubation of PBMC with anti-CD40 antibody plus IL-4 did not affect the proportions of CD4+, CD20+, Fas+ CD4+, and Fas+ CD8+ cells. The addition of T3 to cultured PBMC from controls did not reproduce the changes in CD23+ and CD8+ cells noted in the samples froin GD patients. Thus, T cell-dependent B cell activation, mediated by a CD40 pathway, may reduce the number of CD8+ cells, causing exacerbation of GD.

Adult↗

PubMed1998

Effects of thyroid hormone on catecholamine and its metabolite concentrations in rat cardiac muscle and cerebral cortex.

Clinical and experimental data suggest that thyroid hormone affects the actions of catecholamine (CA). However, the serum or tissue levels of CA during thyroid disorders have not been well defined. Accordingly, we investigated the levels of CA and their metabolites in the cardiac muscle, the cerebral cortex, and the plasma of rats with hyperthyroidism and hypothyroidism versus euthyroid animals. The Neurochem analyzer system (ESA, Inc., Bedford, MA) was used in such determinations. The cardiac muscles of hyperthyroid rats exhibited a 16% decrease in the levels of 1-dopa, 3-methoxytyramine (3-MT) and homovanillic acid (HVA) as compared with those in euthyroid rats. The levels of norepinephrine (NE) in cardiac muscle of these rats increased significantly (5.2-fold) relative to the levels in euthyroid rats. NE was undetectable in the cardiac muscles of the hypothyroid rats. Epinephrine (E) and dopamine (DA) were not detected in the cardiac muscles of the rats with either thyroid disorder. Levels of E and 3,4-dihydroxymandelic acid (DOPEG) were detected only in the cerebral cortex of hyperthyroid rats. The cerebral cortex levels of 3-methyoxytyramine (3-MT), 3,4-dihydroxyphenylacetic acid (DOPAC), metanephrine (MN), and homovanillic acid (HVA) were all significantly increased in the hyperthyroid versus the euthyroid rats. The cerebral cortex levels of DA, NE, normetanephrine (NMN), and VMA in the hyperthyroid rats all showed a significant decrease. Levels of NE, NMN, and DOPAC in the cerebral cortex increased significantly in the hypothyroid rats. The level of VMA was undetectable in cerebral cortex of such animals. Data from studies on cardiac muscle and cerebral cortex indicate that the changes in CA and CA metabolites are responsible in part for the cardiovascular and the central nervous system symptoms observed in hyperthyroidism and hypothyroidism.

Animals↗

PubMed1998

Vitamin E and coenzyme Q concentrations in the thyroid tissues of patients with various thyroid disorders.

To clarify the different roles of free radical scavenging systems in various thyroid disorders, we measured the levels of alpha-, beta-, and gamma-tocopherols and coenzyme Q in the thyroid tissues of patients with thyroid tumors and Graves' disease using high-performance liquid chromatography. The levels of alpha-tocopherols and gamma-tocopherols in the thyroid tissue of patients with papillary carcinoma and the level of gamma-tocopherol in the thyroid tissue of patients with malignant lymphoma were elevated compared with those in normal thyroid tissues. The level of coenzyme Q was reduced in the thyroid tissue of patients with Graves' disease and follicular and papillary thyroid carcinomas. These findings imply that vitamin E and coenzyme Q as scavengers play some role in thyroid follicular cell hyperfunction or dysfunction.

Graves Disease↗

PubMed1998

The pattern of infiltration at the proximal border of hilar bile duct carcinoma: a histologic analysis of 62 resected cases.

OBJECTIVE: To clarify the importance of different patterns of infiltration at the proximal border of hilar bile duct carcinomas. SUMMARY BACKGROUND DATA: There are few detailed pathologic studies on the proximal resection margins in patients with hilar bile duct carcinoma. METHODS: Serial sections of 62 specimens of resected hilar bile duct carcinoma were examined histologically to determine the involved layers and routes of invasion at the proximal border. The degree of cancer extension was determined, and the relation between the length of the tumor-free resection margin and postoperative anastomotic recurrences was analyzed. RESULTS: Mucosal extension was predominant in papillary and nodular tumors, but submucosal extension was predominant in diffusely infiltrating and nodular-infiltrating tumors. Submucosal extension usually consisted of direct or lymphatic invasion. The mean length of submucosal extension was 6.0 mm. Superficial spread of cancer, defined as mucosal extension of more than 20 mm from the main lesion, was seen in 8 specimens. No patient had an anastomotic recurrence when the tumor-free resection margin was greater than 5 mm. CONCLUSIONS: The pattern of infiltration at the proximal border of resected hilar bile duct carcinomas is closely related to the gross tumor type. The length of submucosal extension is usually less than 10 mm. Superficial spread of cancer is seen in more than 10% of cases. A tumor-free proximal resection margin of 5 mm appears to be adequate in hilar bile duct carcinoma.

Adult↗