Search PubMed⌕ Search

Biomedical subjects

Y Kamiyama

Publications and source records attributed to Y Kamiyama.

At least 109 records · Page 6Linked to original sources
PubMed1997

Prophylactic laparoscopic ovarian ablation for premenopausal breast cancer: medical and economic efficacy.

Worldwide analysis showed a highly significant reduction in the annual rates both of recurrence and of death produced by ovarian ablation. We examined the safety, efficacy, and cost-effectiveness of prophylactic laparoscopic oophorectomy for premenopausal breast cancer. Prophylactic laparoscopic oophorectomy was attempted in 15 selected premenopausal patients with breast cancer. After mastectomy, these patients had laparoscopic ovarian ablation as treatment for breast carcinoma with positive estrogen receptors. To evaluate the economic impact of laparoscopic oophorectomy, comparisons were made between patients treated laparoscopically and those treated with conventional surgery, chemotherapy, and hormonal therapy. The average time required for laparoscopic bilateral oophorectomy was 44 min. Oral intake was resumed the next morning, and the patients were discharged 3 days after surgery. No limitation on physical activity and no complications were required during postoperative days. There was no reduction in the overall costs of laparoscopic surgery and conventional surgery in Japan. The cost of one year's supply of tamoxifen was equivalent to the overall cost of surgical oophorectomy. From medical and economic viewpoints, we conclude that laparoscopic ovarian ablation should be considered an alternative to adjuvant chemotherapy in premenopausal women.

Activities of Daily Living↗
PubMed1997

[A survival case of intraoperative pulmonary embolism diagnosed early by transesophageal echocardiography].

An otherwise healthy 36-year-old housewife was diagnosed with advanced cancer of the stomach 5 months after her third parturition. Surgery was performed with the patient under total intravenous anesthesia combined with continuous epidural anesthesia. The course of anesthesia and the operative course were uneventful until the abdominal skin was sutured, when unexplained severe circulatory collapse developed. A widely dissociated PETCO2- PaCO2 suggested pulmonary embolism, and the findings of transesophageal echocardiography corroborated the diagnosis. Infusion of 480,000 units of urokinase in 30 minutes was immediately started via a Swan-Ganz catheter, and intravenous heparin 10,000 units in 24 hours, was administrated continuously. The pulmonary circulation was restored 30 minutes after the start of therapy, resulting in rapid recovery of the patient's systemic circulatory and acid-base status. The patient was safely extubated 19 hours postoperatively.

Adult↗
PubMed1997

Spiral computed tomography scanning after intravenous infusion cholangiography for biliary duct anomalies.

BACKGROUND: Iatrogenic injury of the bile duct during cholecystectomy represents a failure of surgical technique, especially for laparoscopic surgery. Knowledge of the patient's individual ductal anatomy and anomalies preoperatively would be helpful in avoiding such injuries. Therefore, we investigated the anatomy of the biliary duct and any anomalies using spiral computed tomography (SCT) scanning following intravenous infusion cholangiography (IVC-SCT). MATERIALS: Laparoscopic cholecystectomies (LC) were attempted on 437 patients at the Kansai Medical University. Preoperative IVC-SCT and laparoscopic cholangiography were attempted in all of the patients. RESULTS: An overall anomalous union of the cystic duct was seen in 71 (16.2%) out of the 437 patients subjected to IVC-SCT. The following anomalies were observed: right hepatic duct entry in 7 cases (1.6%), parallel low entry in 17 cases (3.9%), posterior spiral entry in 35 cases (8.0%), anterior spiral entry in 7 cases (1.6%), and accessory duct entry in 5 cases (1.1%). The success rate for the LC was 99.5% (435/437). Three patients were switched to open surgery owing to advanced gallbladder cancer and severe adhesions. The success rate for the laparoscopic cholangiography was 97.2% (423 of 435). Intraoperative right hepatic duct injury occurred in only 1 patient with a bile duct anomaly, and it was repaired with laparoscopic T-tube drainage. CONCLUSIONS: The preoperative examination of the biliary tract by IVC-SCT was technically simple, less invasive, and may helpful in avoiding damage to the bile duct, especially in patients with biliary duct anomalies.

Bile Ducts↗
PubMed1997

[Combination use of second generation cephem and isepamicin for the treatment of post-surgical infection of the lower digestive tract].

Effects of combination use of a second generation cephem and an aminoglycoside antibiotic isepamicin (ISP), for the treatment of post-surgical infections of the lower digestive tract were examined from a laboratory and clinical perspective. Thirty-three out of total 35 cases were included in the analysis of the test, while the other 2 cases did not meet the criteria for analysis. ISP was administered in combination with one of the second generation cephems among cefotiam (CTM), cefmetazole (CMZ), or cefuroxime (CXM) for 26 cases of wound infection and 7 cases of peritonitis. The overall efficacy rate was 88%; 92% in wound infection and 71% in peritonitis individually. There was no significant difference in efficacy among different groups. Bacteriological study showed the combination use of any one of the second generation cephems and ISP was very effective in all 14 cases of infections with a single species of bacterium, the efficacy rate was 100%. It was also effective in 9 out of 10 cases with mixed infections of 2 species of bacteria (90%), but effectiveness was diminished in only 6 out of 9 cases with mixed infections of 3 species (67%). Sixty-nine strains were isolated from the 35 cases, more than half of which (44 strains) were Gram-negative; 14 strains of E. coli (20%), 13 strains of E. faecalis (13%) and 6 strains of P. aeruginosa (9%). The MIC50 and MIC90 were, respectively, 1.56 micrograms/ml and 100 micrograms/ml for ISP, 6.25 micrograms/ml and 100 micrograms/ml for CTM, 12.5 micrograms/ml and 100 micrograms/ml for CMZ, and 25 micrograms/ml and 100 micrograms/ml for CXM. The MICs in any combination uses decreased synergistically according to ISP concentration. Adverse events were observed in 3 out of 35 cases, but they were not severe. The results indicated that the combination use of a second generation cephem and ISP was useful and should be one of the choices for the treatment of post-operative infections of the lower digestive tract.

Adult↗
PubMed1996

Histologic features and clinical significance of venous invasion in colorectal carcinoma with hepatic metastasis.

BACKGROUND: In colorectal carcinoma, venous invasion has been related to patient survival. Liver metastasis develops more frequently when venous invasion is present. However, the histologic features and clinical significance of venous invasion are not well understood. METHODS: A histologic study of venous invasion in colorectal carcinoma was performed on 19 patients with synchronous hepatic metastasis (Group A), 16 patients with metacaronous hepatic metastasis (Group B), and 26 patients with Dukes Stage C tumors who survived for 5 years without recurrence (Group C). The histologic features of venous invasion were classified into three types: tumor cells that were distant from the vein walls were categorized as floating type, those filling the lumen of a vein as filling type, and those surrounded by a vein obliterated with inflammatory reaction as occlusive type. RESULTS: Venous invasion was present in 89.5% of Group A patients and 75% of Group B patients, which was significantly higher than the 15.4% observed in Group C patients (P < 0.001). A slight to extensive degree of venous invasion was found in Groups A and B, but no extensive venous invasion was found in Group C. All patients in Groups A and B (except one patient) had floating, filling, or a combination of floating and filling types of venous invasion, whereas all patients in Group C had the occlusive type of venous invasion. A majority of the patients in all three groups showed invasion of extramural veins. CONCLUSIONS: There is a close relationship between venous invasion and the development of liver metastasis in patients with colorectal carcinoma. Patients with no sign of metastasis had a lower incidence and lower extent of venous invasion, and inflammatory damage to the vein walls around the intravenous tumor appeared to reduce the likelihood of distant metastasis.

Adult↗
PubMed1996

Regulation of energy metabolism by interleukin-1beta, but not by interleukin-6, is mediated by nitric oxide in primary cultured rat hepatocytes.

The effects of inflammatory cytokines (interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha) on energy metabolism were studied in primary cultured rat hepatocytes. Adenine nucleotide (ATP, ADP, and AMP) content, lactate production, the ketone body ratio (acetoacetate/beta-hydroxybutyrate) reflecting the liver mitochondrial redox state (NAD+/NADH), and nitric oxide formation were measured. Insulin increased ATP content in hepatocytes and had a maximal effect after 8-12 h of culture. Both interleukin-1beta and interleukin-6, but not tumor necrosis factor-alpha, significantly inhibited the ATP increase time- and dose-dependently. Interleukin-1beta and interleukin-6 also stimulated lactate production. During the same period, interleukin-1beta but not interleukin-6 decreased the ketone body ratio. Furthermore, interleukin-1beta markedly stimulated nitric oxide formation in hepatocytes, and this increase was blocked by NG-monomethyl-L-arginine (a nitric oxide synthase inhibitor) and by interleukin-1 receptor antagonist. NG-monomethyl-L-arginine reversed inhibition of the ATP increase, decrease in the ketone body ratio, and increase in lactate production, which were induced by interleukin-1beta. Interleukin-1 receptor antagonist completely abolished all of the effects induced by interleukin-1beta. These results demonstrated that interleukin-1beta and interleukin-6 affect the insulin-induced energy metabolism in rat hepatocytes by different mechanisms. Specifically, interleukin-1beta inhibits ATP synthesis by causing the mitochondrial dysfunction, a process which may be mediated by nitric oxide.

Adenine Nucleotides↗
PubMed1996

Inflammatory pseudotumor of the liver: report of a case and review of the literature.

Only 56 cases of inflammatory pseudotumor of the liver have been reported in the world literature since its first documentation in 1953. We report herein the case of a 68-year-old man incidentally found to have a lesion in the right lobe of the liver which closely resembled a neoplasm on imaging studies. Thus, partial hepatic resection was performed and histological examination of the resected specimen revealed a diagnosis of inflammatory pseudotumor. Surgical resection is the preferred treatment for inflammatory pseudotumor of the liver, especially in patients for whom a definite histologic diagnosis cannot be made preoperatively or by intraoperative frozen sections. In fact, most of the patients reported in the literature recovered uneventfully after local resection without any postoperative complications, as did our patient.

Aged↗
PubMed1996

Reconstruction of retinal horizontal cell responses by the ionic current model.

An ionic current model of the retinal horizontal cell is constructed. The horizontal cell models are interconnected by gap junctions to form a horizontal cell layer. The light response properties of the L-type horizontal cell are analyzed using this model. We demonstrate the functional role of each ionic current and the role of the feedback loop between cones and horizontal cells. The present study provides insight into the dynamic relationships between characteristics on the cellular level and on the multi-cellular level for producing the light response in horizontal cells.

Action Potentials↗
PubMed1996

Ionic current model of the vertebrate rod photoreceptor.

We describe voltage- and calcium-dependent ionic currents in the photoreceptor inner segments similar to the Hodgkin and Huxley (Journal of Physiology, 117, 500-544, 1952) equations. The model is used to describe both rods and cones by adjusting parameters. To simulate the light response, the inner segment model was connected with the phototransduction model proposed by Torre et al. (Cold Spring Harbor Symposia on Quantitative Biology, 55, 563-573, 1990). The role of individual ionic currents in the inner segment in shaping the light response was analyzed through computer simulations. The results suggest that: (1) the transient hyperpolarization to a bright flash is generated by Ih; (2) the oscillation after prolonged hyperpolarization in rods results from the interaction among Ica, IK(Ca), and ICI(Ca). Since the present model describes the biophysical processes from phototransduction to voltage response, the model can be used for analyzing the light response properties of the photoreceptors quantitatively.

Animals↗
PubMed1996

Ionic current model of bipolar cells in the lower vertebrate retina.

We propose an ionic current model of bipolar cells based on the published experimental data. Five types of ionic currents identified in bipolar cell bodies, Ih, IKv, IA, ICa and IK(Ca) were described by a mathematical formulation similar to the Hodgkin and Huxley (Journal of Physiology, 117, 500-544, 1952) equations. The model parameters were estimated from the voltage clamp data. In simulation, we demonstrate that the present model reproduces not only the voltage clamp responses but also the current clamp responses of the bipolar cells. As a result, the model provides a better understanding of the functional role of the ionic currents in bipolar cells in generating the electrical responses.

Animals↗
PubMed1996

Interleukin 1 beta markedly stimulates nitric oxide formation in the absence of other cytokines or lipopolysaccharide in primary cultured rat hepatocytes but not in Kupffer cells.

To investigate whether a single inflammatory cytokine could stimulate nitric oxide formation in the absence of other cytokines or lipopolysaccharide (LPS), NO was measured by the redox chemiluminescence method in primary cultured rat hepatocytes and in rat Kupffer cells. Interleukin (IL) 1 beta, but neither IL-6, tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), nor LPS stimulated NO formation in a dose-dependent manner and induced half-maximal effects at 30 pmol/L. Maximal stimulation was achieved at 12 to 16 hours after the addition of 1I nmol/L of IL-1 beta, and was 50- to 60-fold above basal levels in rat hepatocytes. The combined effect of these cytokines with LPS or IFN-gamma on NO formation was also examined. Neither LPS nor IFN-gamma affected the IL-1 beta-induced NO formation. TNF-alpha, however, stimulated IL-1 beta-induced NO formation, while IL-6 inhibited it, although independently these cytokines had no effect on NO formation. None of the cytokines tested stimulated NO formation in cultured rat Kupffer cells. In hepatocytes, the NO formation induced by IL-l beta was blocked by both the NO synthase (NOS) inhibitor NG-monomethyl-L-arginine (L-NMMA) and by IL-1 receptor antagonist (IL-1ra). Furthermore, IL-1 beta markedly increased NOS activity, and this increase in activity was accompanied by the expression of inducible NOS (iNOS) messenger RNA (mRNA). This study clearly demonstrated that IL-1 beta markedly stimulates NO formation in hepatocytes, in the absence of other cytokines or LPS.

Animals↗
PubMed1996

Gallbladder cancer with a low junction of the cystic duct or an anomalous pancreaticobiliary junction.

OBJECTIVE: To evaluate conditions similar to those of carcinogenesis of the gallbladder between the gallbladder with a low junction of the cystic duct (LJCD) and an anomalous pancreaticobiliary junction (APBJ). DESIGN: Retrospective and clinicopathological analysis of patients with gallbladder carcinoma. SETTING: First Department of Surgery, Kansai Medical University. PATIENTS: Examination of 47 patients (7 men and 40 women; average age: 67.8 years) with gallbladder carcinoma revealed 7 patients (14.9%; 1 man and 6 women; average age: 67.8 years) with LJCD and 6 patients (12.8%; 6 women; average age: 60.3 years) with APBJ. METHODS: Clinical findings in both groups were compared with those of the 34 patients who remained after exclusion of the data of the above 7 patients with LJCD and 6 patients with APBJ. The data of the three groups were examined by the chi 2 test at the 5% level of significance. RESULTS: Most of the gallbladder cancer patients with LJCD or APBJ had gallstones. The biliary amylase levels determined in the gallbladder of patients with LJCD or APBJ were remarkably high. CONCLUSION: The results indicate that patients with LJCD or APBJ are more likely to develop carcinoma of the gallbladder. The factors responsible for carcinogenesis may be alteration of the bile content due to reflux of pancreatic enzymes through the LJCD or APBJ, and mechanical irritation due to gallstones. Therefore, these pathological conditions in patients with LJCD are similar to those experienced in patients with APBJ.

Aged↗
PubMed1996

Hepatocyte volume as an indicator of hepatic functional reserve in cirrhotic patients with liver tumours.

Using computed tomography (CT), measurements of whole liver volume have been used for the assessment of pre-operative functional reserve in cirrhotics. However, measurements of hepatocyte volume, which exclude stromal fibrous tissue, are considered to more directly reflect hepatic functional reserve. We investigated the relationship between total hepatocyte volume and each of the parameters of conventional liver function. Indocyanine green (ICG) tests and blood analyses for the assessment of liver function were performed prior to surgery in cirrhotic patients with liver tumours. Pre-operative liver volume was determined by integrating images of each liver area obtained by CT. Liver area was measured by an image processing program that traced the profile of the liver image while excluding the tumorous area. Sections of normal tissue stained by the haematoxylin-eosin method, were obtained from the resected liver. Using these sections, a hepatocyte area: whole tissue area ratio was calculated using the image processing program, by tracing the profiles of the hepatocyte nodules. The total volume of hepatocytes was then calculated by multiplying the liver volume by this ratio. The hepatocyte volume per unit bodyweight was significantly correlated with ICG tests and with many other parameters of normal liver function. However, the liver volume per unit bodyweight was correlated only with the plasma ICG disappearance rate and with the blood platelet count. These observations suggest that the functional reserve of the cirrhotic liver is assessed more precisely by hepatocyte volume than by liver volume.

Adult↗
PubMed1996

[Selective thermocoagulation of unresectable malignant tumors using radiofrequency].

Based on our experimental findings on porcine liver, we have been conducting a clinical trial of selective hyperthermia by radiofrequency (RF) capacitive heating with laparotomy for patients with unresectable malignant tumors. In 10 patients with malignant tumors (8 carcinoma of the pancreas, 2 carcinoma of the gallbladder), laparotomy and RF heating were performed after informed consent. The local heat coagulation was produced by heating equipment using 13.56 MHz radiofrequency produced by Omron Corporation, Japan. Four 2-cm electrode needles were placed in the tumor in a square array at intervals of 2.0 cm. Hyperthermia was given for 30 min with a controlled temperature of 50 degrees C in the RF field (2 x 2 x 2 cm3). That of the surrounding area was maintained at less than 40 degrees C. The calculated volume treated by RF ranged between (2 x 2 x 2 cm3) x 1 and (2 x 2 x 2 cm3) x 6. We followed all patients by computed tomographic (CT) scan 2 weeks after coagulation. Tumor markers in the blood were assayed before and 14 days after heating. Follow-up CT scans demonstrated that after the tumor mass had been heterogeneously enhanced, it changed to a homogeneous low-density area in 6 of 10 patients. The levels of tumor markers decreased to lower than the pre-treatment values in 9 of 10 patients. In all patients, the changes in CT scans and/or decrease in the markers were confirmed. Complications such as bleeding or abscess formation were not observed. It was suggested that the selective hyperthermia was safely produced by this equipment. The encouraging results in these patients justify further clinical trials.

Biomarkers, Tumor↗
PubMed1995

Three-dimensional reconstruction of the biliary tract using spiral computed tomography.

Spiral computed tomography (SCT) is a recently introduced technique which enables scanning of one large volume with no interscan intervals. Three-dimensional reconstruction using this technique is emerging as an effective means of identifying complex anatomical relationships. Ninety-two patients with cholecystolithiasis including ten with choledocholithiasis were investigated. All underwent SCT after oral and intravenous infusion cholangiography (IVC-SCT) and 22 were also examined by endoscopic retrograde cholangiography (ERC). IVC-SCT showed significantly more anatomical detail than conventional intravenous infusion cholangiography (IVC). The junction between the cystic duct and the common bile duct could be identified before surgery in 19 of 22 patients undergoing ERC, in 18 of 22 receiving IVC-SCT and in five of 22 undergoing IVC. Significant differences were noted between IVC-SCT, ERC and conventional IVC. Three-dimensional surface reconstruction of the biliary tract is useful in the evaluation of anatomical relationships between the cystic duct and the common bile duct (clearly seen in 86 per cent of cases). Three-dimensional reconstruction using SCT scanning is useful for anatomical assessment before laparoscopic cholecystectomy.

Adult↗
PubMed1995

Growth, development and nutritional status in Japanese children under 2 years on continuous ambulatory peritoneal dialysis.

We examined the growth, development and nutritional status over a period of 10 years of 15 young children (< 2 years old) on continuous ambulatory peritoneal dialysis (CAPD). There were 6 males and 9 females with a mean age of 12.5 months, mean weight of 6.3 kg, mean height of 66.2 cm at the start of CAPD and a mean duration of therapy of 2.6 years. Height, weight, head circumference, development quotient (DQ), blood chemistry and dietary intake were assessed over a period of 10 years. The patients' mean height standard deviation score (SDS) did not change significantly (from -2.51 to -2.74) during CAPD therapy. The mean growth velocity index (GVI) during CAPD was 76.5% and correlated positively with energy intake but not with protein intake. The mean DQ was low (67.0%) at the start of CAPD and 69.3% at the end of CAPD. DQ did not correlate with energy intake, GVI, head circumference SDS or with the weight/height ratio; however, 2 patients with low DQ (< 60%) had a low energy intakes. Although most patients had a low DQ, the IQ at 5-6 years of age was normal in all patients except 1 without cerebral disease. Our study showed minimal growth (delta SDS) and mental developmental (IQ) delays during CAPD therapy, but an adequate nutritional intake must be assured to obtain the above results.

Blood Proteins↗
PubMed1995

Use of technetium 99m diethylenetriamine-pentaacetic acid-galactosyl-human serum albumin liver scintigraphy in the evaluation of preoperative and postoperative hepatic functional reserve for hepatectomy.

BACKGROUND: Technetium 99m diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (99mTc-GSA) is a new liver scintigraphy agent that binds to the asialoglycoprotein receptors. We evaluated the clinical use of 99mTc-GSA for the perioperative assessment of hepatectomy. METHODS: Thirty-six patients with hepatocellular carcinoma were admitted for elective hepatectomy. 99mTc-GSA scintigraphy was obtained after the intravenous injection of 99mTc-GSA, and a modified receptor index (MRI) was calculated. 99mTc-GSA scintigraphy, conventional liver function, the plasma disappearance rate, and the 15-minute retention rate of indocyanine green (ICGR15) were carried out before operation and every 1 to 3 months after operation. The relationships between several systemic hemodynamic parameters, histologic activity index (HAI), plasma disappearance rate, and ICGR15 or MRI values were estimated. RESULTS: A significant correlation was obtained between the MRI and ICGR15 (r = 0.6231, p < 0.001). Plasma disappearance rates correlated well with systolic volume and left cardiac work, whereas MRI values did not correlate with these systemic hemodynamics. Preoperative discrepancies between the values of MRI and ICGR15 were seen in eight cases. In these cases the MRI values correlated well with HAI scores (p < 0.05) but there was no significant correlation between ICGR15 values and the HAI scores. CONCLUSIONS: These results suggested the use of 99mTc-GSA scintigraphy as a easy and reliable method for determining liver functional reserve.

Adult↗