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Biomedical subjects

J Yamamoto

Publications and source records attributed to J Yamamoto.

At least 163 records · Page 9Linked to original sources
PubMed1997

[The effect of CO2 and apnea on cochlear and middle ear blood flow in guinea pigs].

The effect of 10% CO2 (in air) and apnea on cochlear blood flow (CBF) and middle ear blood flow (MEBF), capillary vessel diameters and blood pressure (BP) were investigated in guinea pigs. Intravital microscopic techniques (IVM) using video system, and laser Doppler flowmetry (LD) were used. MEBF was measured in the blood vessels of the middle ear mucosa over the cochlea and CBF was measured in the lateral wall vessels in the second or third cochlear turn. During 10% CO2 respiration for 10 min, the highest vessel diameter dilated about 11% in the middle ear and 5% in the cochlea. During 5 minutes apnea, the highest vessel diameter constricted about 30% in the middle ear and 5% in the cochlea. Elevation of PCO2 dilate blood vessels with constant PO2, but constriction of blood vessels as observed in extremely low PO2 range even if PCO2 was elevated. The ratio of the change in blood flow volume to the change in BP was obtained after the change in blood flow volume was calculated from blood flow velocity and blood vessel diameter. The mean change of ratio in MEBF was a 10% decrease with 10% CO2, 28% decrease with apnea in IVM. The mean change of ratio in CBF was a 44% increase with 10% CO2, 14% increase with apnea in IVM, 67% increase with 10% CO2, 42% increase with apnea, in LD. The change of CBF in LD was about 20% larger than in IVM. Our results showed that CBF belonging to vertebral artery system was more strongly maintained in association with autoregulation even under conditions of low PO2 or high PCO2 compared to MEBF in the external carotid artery system. It was suggested that blood flow behavior was significantly different between the middle ear and inner ear.

Animals↗
PubMed1996

An aggressive therapeutic approach to carcinoma of the body and tail of the pancreas.

BACKGROUND: Prognosis of patients with adenocarcinoma of the pancreatic body and tail is extremely poor. Anatomically, this part of the pancreas is thin, and cancerous invasion to the retropancreatic structures occurs easily. The majority of patients have residual tumor in the retroperitoneal tissues after conventional distal pancreatectomy. METHODS: Between 1962 and 1979, 10 patients with carcinoma of the pancreatic body underwent simple distal pancreatectomy. Between 1980 and 1990, 22 patients including 7 with distant metastasis underwent a more aggressive approach intended to achieve longer survival: distal pancreatectomy with extended dissection of the lymph nodes and adjacent structures, especially into the retropancreatic space. After 1984, intraoperative ŕadiation (IORT) by electron beam and chemotherapy by hepatic infusion plus systemic injection of mitomycin C (MMC) were added for 7 patients without distant metastasis. RESULTS: The 10 patients who underwent pancreatectomy between 1962 and 1979 all died within 20 months after their operations. Conversely, the patients treated with an aggressive approach between 1980 and 1990 survived longer; the 5-year survival rate for 15 patients without distant metastasis was 29%, though the 7 patients with distant metastasis died within 10 months of their operations. There were 4 long term survivors (> or = 5 years); 3 of whom received IORT and chemotherapy with MMC. Invasion to the retropancreatic soft tissues was present in 95% of the resected specimens from the 22 patients. However, invasion to the surgical margin at the posterior surface of the resected specimen was present in only 36% after extended resection of the retropancreatic structures. CONCLUSIONS: Survival improved for this disease after distal pancreatectomy with extended dissection, especially of the retropancreatic structures, adjuvant IORT, and chemotherapy had been performed.

Adenocarcinoma↗
PubMed1996

Successful radical surgery for an undifferentiated gallbladder carcinoma with lymph node metastases to the mesocolon.

We report successful radical systematic surgery for an undifferentiated gallbladder carcinoma with metastasis to the mesocolonic lymph nodes. The patient, a 70-year-old woman, was admitted with abdominal fullness and appetite loss. Imaging modalities revealed a 10-cm tumor originating from the gallbladder and infiltrating both the liver and transverse colon. As multiple mesocolonic lymph node metastasis was confirmed on laparotomy, right hemicolectomy with systematic lymph node dissection (D3 resection) was performed, in addition to extended cholecystectomy with partial resection of segments 4, 5 and 6 of the liver and distal gastrectomy. Histologically, the tumor was diagnosed as an undifferentiated carcinoma, and metastases were indentified in the mesocolonic lymph nodes (17/50 nodes) but not in the peri-gallbladder lymph nodes (0/16 nodes). The patient has been recurrence-free for 4 years after the operation. This case illustrates that even if gallbladder cancer infiltrates into adjacent organs with regional lymph node metastasis, it is of value to perform radical surgery with systematic lymph node dissection for the involved organs.

Aged↗
PubMed1996

Effect of heavy alcohol intake on long-term results after curative resection of hepatitis C virus-related hepatocellular carcinoma.

We studied the effect of heavy alcohol intake (ethanol intake > or = 80 g/day for > or = 5 yr) on long-term results in 53 patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) who had undergone curative hepatic resection. Cell proliferative activity in the tumor and non-tumorous liver was also assessed by counting argyrophilic nucleolar organizer region-associated proteins (Ag-NOR) in the resected specimens. Twenty patients (20 males, 0 females) were positive for heavy alcohol intake [AI(+)] and 33 (28 males, 5 females) were not [AI(-)]. All patients were positive for HCV antibody and negative for hepatitis B surface antigen. Carcinoma recurred within 3 to 51 postoperative months in 42 (79.2%) of the 53 patients. The median disease-free survival time was 12.6 mo in the AI(+) group and 25.4 mo in the AI(-) group (P < 0.01). The AI(+) group also had significantly poorer survival than the AI(-) group (P < 0.05, 3-year survival rate: 66.7% vs. 93.5%). HCC tumor in the AI(+) group showed significantly increased proliferative activity compared with that in the AI(-) group (P < 0.05, Ag-NOR number: 2.3 +/- 0.8 vs. 1.9 +/- 0.4). However, there was no significant difference between the numbers of Ag-NORs in non-tumorous liver from these two groups (1.5 +/- 0.2 vs. 1.5 +/- 0.2). Patients with heavy alcohol intake should be followed particularly closely, even if they have received curative surgery, since heavy alcohol intake is closely related to a poor postoperative prognosis.

Carcinoma, Hepatocellular↗
PubMed1996

Quantification of leucocyte elastase and cathepsin G in plasma by a simple method: effect of elastase in plasma levels of D-dimer and thrombomodulin.

The purpose of this study was to determine levels of leucocyte elastase and cathepsin G in the plasma of patients in various pathological states, in which plasma increases or decreases in coagulation and fibrinolytic factors were seen. Simple methods were developed to measure the leucocyte proteinases and the results were correlated with conventional assays of coagulation and fibrinolytic factors. The total number of patients and total number of plasma samples examined were 340 and 1292, respectively. No correlation was observed between the plasma levels of elastase and cathepsin G, and plasminogen, fibrinogen and leucocyte counts. There was a weak overall correlation, however, between the leucocyte proteinases and each of the four parameters: D-dimer, thrombomodulin, antithrombin III and platelet count. There was a strong correlation between leucocyte proteinases and D-dimer and thrombomodulin in those patients with plasminogen levels within the normal range. Increased D-dimer levels, as well as plasmin, may suggest that elevated leucocyte proteinases contribute to elevated fibrinolytic mechanisms in these instances.

Biological Assay↗
PubMed1996

[Surgical treatment of small hepatocellular carcinoma].

Two hundred thirty-five patients with small hepato-cellular carcinomas (HCCs) (mixed hepatocellular and cholangiocellular carcinoma included) measuring no more than 3 cm in diameter treated by surgical resection between 1980 and 1990 were reviewed retrospectively. Ninety-nine percent of the patients also had chronic hepatitis and 73% were diagnosed histologically as having liver cirrhosis. The operative and hospital mortality rates were 0.4% and 1.3%, respectively. The number of tumors, intrahepatic metastasis and vascular invasion were significant prognostic factors. Overall the 1-,3-and 5-year survival rates (operative deaths included) were 93.2%, 72. 7%, and 49.7%, and those of 144 patients treated in the late 80s (1986-1990) were 93.6%, 76.3%, and 52. 1%, respectively. These results were appreciably better than those for percutaneous ethanol injection therapy (PEIT) and transcatheter arterial embolization therapy (TAE) reported previously. In particular, the survival of the patient with single tumor demonstrated a clear advantage of surgery. The selection of treatment modalities is discussed, and our present standard strategy for surgical treatment is described.

Carcinoma, Hepatocellular↗
PubMed1996

Amount of pollen has an effect on the systemic and local levels of soluble ICAM-1 in patients with seasonal allergic rhinitis.

We investigated whether the amount of antigen has an effect on the systemic and local levels of soluble ICAM-1 (sICAM-1) in patients with pollinosis, and assessed its biologic significance. The levels of subjective symptoms and sICAM-1 in sera and nasal epithelial lining fluids (ELF) from 14 subjects with pollinosis (allergic group) and eight healthy subjects (control group) were measured from pre- to postseason in 1993 (total pollen count: 10,854/cm2) and 1994 (total pollen count: 415/cm2), and the results were compared with each other among the four groups. The levels of subjective symptoms and sICAM-1 in ELF from the allergic group significantly increased during the season in both 1993 and 1994. However, there was a significant difference (P < 0.01) between the levels of those in 1993 and those in 1994 during the season. The levels of sICAM-1 in sera from the allergic group were significantly upregulated during the seasons and postseasons only in 1993, and there was a significant difference (P < 0.05) between the levels in 1993 and those in 1994 during the postseason. We conclude that amount of pollen has an influence on the local and systemic levels of sICAM-1, as well as the scores of subjective symptoms, in patients with seasonal allergic rhinitis.

Adult↗
PubMed1996

Effects of NO-donors on thrombus formation and microcirculation in cerebral vessels of the rat.

Sodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 micrograms/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 micrograms/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction.

Animals↗
PubMed1996

[Three-dimensional-CT pancreatography under balloon-ERP in the pancreatic diseases--its method and usefulness].

Three-dimensional-CT pancreatography (3D-CTP) under balloon-ERP was carried out in 13 patients with the pancreatic diseases. Tapering stenosis of pancreatic duct in 2 patients out of 2 with pancreatic cancer, shape of cyst and relationship between cyst and pancreatic duct in 7 patients out of 7 with pancreatic cysts, and irregularity of wall of pancreatic duct in 2 patients out of 3 with chronic pancreatitis was reconstructed by 3D-CTP, stereographically. Moreover, the confluence of cyst and pancreatic duct in 3 out of 7 pancreatic cysts did not become clear on balloon-ERP, but it was distinct on 3D-CTP. It is suggested that 3D-CTP is useful in understanding pancreatic diseases stereographically, and can be applied to operative simulation, interventional radiology and differential diagnosis on them.

Adult↗
PubMed1996

Recurrence of hepatocellular carcinoma after surgery.

A total of 386 patients who underwent complete resection of hepatocellular carcinoma over an 8-year period were assessed retrospectively for tumour recurrence. Some 219 (56.7 per cent) of the patients developed recurrence. Patients with a greater degree of cirrhosis showed a longer interval to recurrence; the median (range) interval until recurrence was 7.9 (1.8-84.2) months in patients with a normal liver, 13.4 (2.0-79.5) months in those with chronic hepatitis and 16.7 (1.5-73.1) months in those with cirrhosis. Intrahepatic recurrence was observed more frequently in either the same (26.4 per cent) or the adjacent (24.8 per cent) Healey segment than in the lobe contralateral to the primary tumour (17.8 per cent). The presence of portal venous invasion and/or intrahepatic metastasis, underlying liver cirrhosis and perioperative blood transfusion were determined to be independent predictors of recurrence by multivariate analysis. Because intrahepatic spread of hepatocellular carcinoma occurs in a segment-by-segment manner, surgeons should use an anatomically wide resection within the hepatic functional reserve.

Adult↗
PubMed1995

Processing and activation of recombinant mouse mastocytoma histidine decarboxylase in the particulate fraction of Sf9 cells by porcine pancreatic elastase.

Mature 53 kDa histidine decarboxylase (HDC) peptide is produced from a precursor 74 kDa peptide. The mechanism of specific cleavage by processing enzyme is unknown. Using the recombinant mouse 74 kDa HDC, we found that porcine pancreatic elastase specifically converted the inactive 74 kDa HDC to its active form of 53 kDa HDC.

Animals↗