Biomedical subjects

H Anai

Publications and source records attributed to H Anai.

121 records · Page 7Linked to original sources

PubMedDate not supplied

Detection of total assist and sucking points based on pulsatility of a continuous flow artificial heart: in vitro evaluation.

We investigated the basic characteristics of the pulsatility of motor current with an in vitro mock circuit that consists of a sac-type pulsatile pump (simulating the natural left ventricle), three reservoirs, and our mixed flow pump (MFP). There are three alternatives at the inlet of the MFP: 1) the left atrium (LA), 2) the left ventricle (LV), and 3) both (LALV). The motor current waveform was monitored. The pump speed of the MFP was changed from 0 to 7,000 rpm. We calculated the index of motor current amplitude (ICA), which was obtained from the amplitude of the motor current waveform divided by the simultaneous mean value. The ICA plotted against the pump speed had a peak point (t-point) that highly corresponded with the turning point from partial to total left heart assistance. The ICA also had a second specific point (s-point) that corresponded with the beginning of severe sucking. In LV and LALV aortic bypass, t- and s-points could clearly be detected. In LA aortic bypass, however, early and severe sucking occurred, and t- and s-points were not manifest. These data suggest that the assist status of continuous flow artificial heart can be estimated by detecting the t- and s-points.

Blood Flow Velocity↗

PubMedDate not supplied

Gastrointestinal stromal tumor arising in the rectovaginal septum.

We report herein a rare case of malignant gastrointestinal stromal tumor (GIST) originated from the rectal wall, which presented as a tumor on the rectovaginal septum. A 54-year-old Japanese woman, gravida 4, para 3, was admitted complaining of anuresis and severe constipation. She had a history of hysterectomy and right salpingo-oophorectomy for uterine leiomyoma 11 years previously. Pelvic examination revealed an 8.5 x 7.5 x 7.5 cm hard mass in the rectovaginal space. The inferior border of the tumor was 2 cm from the vaginal introitus and 2 cm from the anus. Computed tomography and magnetic resonance imaging showed a well-circumscribed soft-tissue mass filling the rectovaginal space. Urinary bladder and rectum were markedly compressed and displaced. Colon fiberscopy revealed invasion of the tumor into the rectal mucosa. An abdominoperineal resection of the rectum with posterior vaginal wall resection and pelvic lymphadenectomy was performed. The resected specimen showed a rectal submucosal tumor that was 8 x 8 x 7 cm in size. The tumor was diagnosed as a malignant GIST. Immunohistochemical analysis confirmed this diagnosis. The patient is now healthy without evidence of recurrence at 13 months after surgery. Gynecologists should be aware of rectal GIST arising in the rectovaginal space as a differential diagnosis of vaginal submucosal tumor.

Diagnosis, Differential↗

PubMedDate not supplied

Clinical significance of natriuretic peptides and cyclic GMP in hemodialysis patients with coronary artery disease.

BACKGROUND: Plasma concentrations of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and cyclic guanosine monophosphate (cGMP) are suitable markers of 'dry body weight' (DW) in hemodialysis (HD) patients. However, it is still unknown whether these markers can be applied to patients with renal failure and coronary artery disease (CAD). We examined the reliability of these peptides as volume markers in HD patients with CAD. We also assessed the relationship between natriuretic peptides and indices of left ventricular (LV) function. METHODS: Plasma concentrations of ANP, BNP and cGMP were determined before and after HD in patients with CAD (group 1, n = 19, mean age 63 +/- 12 years) and were compared with those of patients without cardiac disease (group 2, n = 20, age 61 +/- 15 years). Using data obtained by cardiac catheterization, we examined the relationship between natriuretic peptides and indices of LV function in HD patients with CAD. RESULTS: Baseline ANP (244 +/- 205 pg/ml), BNP (713 +/- 928 pg/ml) and cGMP (29.6 +/- 21.6 pmol/ml) were significantly higher in group 1 than in 11 healthy volunteers (18.6 +/- 9.9 pg/ml, 7.7 +/- 7.6 pg/ml, cGMP 8.9 +/- 4.9 pmol/ml, respectively). HD significantly reduced plasma ANP (87 +/- 75 pg/ml) and BNP (477 +/- 702 pg/ml) although they were still above normal control. HD reduced plasma cGMP (7.2 +/- 4.5 pmol/ml) to normal values, suggesting the elimination of cGMP across the dialyzers. Baseline levels of ANP, BNP and cGMP in group 2 were less than those of group 1 but higher than the control. HD reduced natriuretic peptides in group 2 to levels lower than those in post-HD group 1. After HD, there was no significant correlation between reductions in body weight and changes in ANP or BNP. Baseline ANP and BNP levels closely correlated with pulmonary artery pressure, pulmonary artery wedge pressure, left ventricular end-diastolic pressure and left ventricular ejection fraction. A significant correlation was observed between BNP levels and the severity of CAD. CONCLUSION: ANP, BNP and cGMP seem to be a useful markers for fluid overload but not for DW in HD patients with CAD. Plasma ANP and BNP might be useful markers for left ventricular function.

Atrial Natriuretic Factor↗

PubMedDate not supplied

Postoperative adjuvant immunochemotherapy and infiltration of dendritic cells for patients with advanced gastric cancer.

To determine the group of patients for whom a biological response modifier is useful, the efficacy of postoperative adjuvant immunotherapy was investigated with regard to infiltration of dendritic cells (DC) in patients with advanced gastric cancer who underwent absolute curative resection. The infiltration of DC was classified into marked and slight. The chemotherapy group was prescribed mitomycin C and tegafur, while for the immunochemotherapy group a biological response modifier, PSK, was also prescribed in survival between the chemotherapy and immunochemotherapy groups. In patients with slight infiltration, however, the 5 - year survival rates were 0% in the chemotherapy and 15% in the immunochemotherapy group. Patients given PSK survived longer than those given chemotherapy only (P less than 0.05). Therefore, adjuvant immunotherapy may be considered for patients with advanced gastric cancer with slight infiltration of DC.

Adjuvants, Immunologic↗

PubMedDate not supplied

Dipyridamole potentiates adriamycin cytotoxicity by a mechanism other than inhibiting nucleoside uptake.

Nitrobenzylthioinosine (NBTI) and dipyridamole (DP) are competitive inhibitors of cellular nucleoside uptake. Although combined treatment of HeLa cells with adriamycin (ADM) and DP enhanced ADM cytotoxicity in cell growth and clonogenic assays, the combination of ADM and noncytostatic levels (less than 1 microM) of NBTI did not change the cytotoxic potential of ADM in vitro. DP enhanced the inhibition of clonogenicity by ADM, even in nucleoside-enriched mediums. These results suggest that the synergy between ADM and DP was hardly due to the inhibition of nucleoside uptake by DP, but was due to the enhancement of intracellular ADM accumulation by DP.

Biological Transport↗

PubMedDate not supplied

5-Fluorouracil is converted to F-nucleotides more extensively and is more cytotoxic in poorly differentiated than in well differentiated human gastric carcinoma.

The sensitivity to 5-fluorouracil (5-FU) was examined in 40 well differentiated and 50 poorly differentiated gastric cancer tissues and 15 normal tissues, using the in vitro succinate dehydrogenase inhibition (SDI) test. The tissue phosphorylating and degrading activities of 5-FU were compared in each type of tumor and in the normal tissues. Decreases in succinate dehydrogenase (SD) activity were more apparent in the poorly differentiated cancer tissues than in the well differentiated cancer tissues (p less than 0.005), and than in the normal tissues (p less than 0.001), exposed to 5-FU. The rate of sensitivity to 5-FU was higher in the poorly differentiated than in the well differentiated tissues and than in the normal tissues. The phosphorylating activities of 5-FU, in pathways involving uridine (Urd) phosphorylase and Urd Kinase, and thymidine (dThd) phosphorylase and dThd Kinase, were 1.7 fold higher in the poorly differentiated than in the well differentiated tissues and several fold higher than in the normal tissues (p less than 0.05-p less than 0.001). The degrading activity of 5-FU was similar in both types of tumor and in the normal tissues. Our findings show that 5-FU is actively metabolized to 5-FU-nucleotides in poorly differentiated tissues after incorporation into the tumor cells. 5-FU seems to have an increased susceptibility in cases of poorly differentiated gastric carcinoma.

Culture Techniques↗

PubMedDate not supplied

Cytotoxicity of N4-behenoyl-1-beta-D-arabinofuranosylcytosine through gradual conversion to 1-beta-D-arabinofuranosylcytosine in HeLa cells.

The metabolism of 1-beta-D-arabinofuranosylcytosine (ara-C) and N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC) was studied in Hela cells. After the cells were exposed to ara-C at a concentration of 20 micrograms/ml or BH-AC at 46.5 micrograms/ml for 1, 3, 6, 12 or 24 hr, the level of ara-C was determined using the radioimmunoassay method, and the level of BH-AC and 1-beta-D-arabinofuranosyluracil (ara-U), using high-performance liquid chromatography. In the ara-C-treated cells, the intracellular ara-C increased to 1.26 micrograms/g cells after exposure for 6 hr, and ara-C was rapidly changed to ara-U in the cells and in the medium. In the BH-AC-treated cells, the intracellular BH-AC increased after exposure for 24 hr and BH-AC was gradually converted to ara-C in the cells: the intracellular level of ara-C was only 15% of that of BH-AC after exposure for 24 hr. BH-AC level in the medium persisted for 24 hr, at the initial concentration. Our findings show that BH-AC is stable compared to ara-C and gradually converts to ara-C. This conversion is presumably a critical step in the antineoplastic effect of BH-AC.

Antineoplastic Agents↗

PubMedDate not supplied

An implantable left ventricular assist system with an electrical impedance monitoring and control system.

The authors developed an implantable left ventricular assist system (LVAS) for bridge to transplant of rather small sized adults. The pump was made of segmented polyether polyurethane and was 86 mm in diameter, 50 mm in height, with a 70 ml nominal stroke volume. A percutaneous drive line was connected with an external pneumatic control drive unit (CDU). In chronic animal experiments using 11 adult goats, the pump was installed between the LV apex and the descending aorta and was placed in the abdominal wall. Five goats were killed after 4 to 14 weeks while in good physical condition, and one is ongoing. There were no prominent thromboembolic symptoms despite no anti-thrombogenic agent being used. The new electrical impedance-based monitoring and control system (Z system) was installed in the CDU. In this Z system, automatic calibration was performed periodically for several seconds while the drive condition was changed to ensure full-fill of the blood pump. The full-fill to full-empty drive was well controlled by this Z system. In conclusion, the new Z system is practical and useful for monitoring and control of an implantable pump, giving this LVAS a promising place in clinical use.

Adult↗

PubMedDate not supplied

Postgastrectomy anticancer chemotherapy for stage IV gastric cancer equally tolerable for patients under and over age 65.

We compared the survival time and drug toxicity between patients with stage IV gastric cancer who were over and under 65 years. All had undergone gastric resection followed by treatment with mitomycin C and a fluorinated pyrimidine. There were no differences in prognostic factors or doses of drugs prescribed between the two groups, nor were there differences in survival rates or toxicities. As advanced chronological age is not sufficient justification to limit or withhold treatment with anticancer drugs, postoperative chemotherapy should be designed for patients with gastric cancer, regardless of age.

Adult↗

PubMedDate not supplied

In vitro reactivity to a protein-bound polysaccharide PSK of peripheral blood lymphocytes from patients with gastrointestinal cancer.

The effect of PSK, a protein-bound polysaccharide and an immunomodulator, on lymphocytes was examined in vitro for 36 patients with gastric cancer and 26 with colorectal cancer. Cultured lymphocytes with PSK at 100 micrograms/ml increased the level of DNA synthesis, as determined by the 3H-thymidine uptake, from 0.9 to 3.0 fold, compared to the PSK non-treated cells. The increase was 1.36 +/- 0.46 fold for the gastric cancer cases and 1.37 + 0.45 fold for the colorectal cancer cases, and these levels were significantly the finding of 1.93 + 0.55 fold for a control group consisting of 15 healthy volunteers (P < 0.01). When the 1.3 fold increase of 3H-thymidine uptake was defined as the PSK-reactive group, 52.8% (19/36) of the patients with gastric cancer and 50.0% (13/26) for colorectal cancer were found in the PSK-reactive group. The PSK-reactive group demonstrated no relation to the age and sex of the patients, tissue differentiation type or tumor advancement. Our findings thus show that the in vitro activation of lymphocytes by PSK can help identify the candidates with either gastric or colorectal cancer who are the best suited to undergo immunochemotherapy including treatment with PSK.

Adjuvants, Immunologic↗

PubMedDate not supplied

A two stage axial flow pump. New approach to reduction of hemolysis.

From an engineering point of view, the suitable revolution number for high efficiency operation of an axial flow pump is known. A multistage axial flow pump is a useful tool for reducing revolution number with a high efficiency axial flow pump. A two stage (25) axial flow pump designed at a 5 L/min flow rate and a 100 mmHg pressure head was evaluated in three kinds of in vitro hemolysis tests. Each stage design point of the 2s pump was tested at a 5 L/min flow rate and a 50 mmHg pressure head. Specific speed and revolution number of the 2S pump were 1400 rpm, m3/min, m, and 15500 rpm, respectively. In the first test the 2S pump was compared with two single stage axial flow pumps (1S-A and 1S-B100) designed by the same method. The specific speed of the 1A was the same as that of the 2S pump, which was driven at 26000 rpm. The impeller of the 1S-B100 was the same as that of the 2S pump, which was driven at a 22000 rpm RN and a 1100 specific speed. The 2S pump was separated into two single stage axial flow pumps and the effect of series operation on hemolysis was evaluated in the second test. In the third test the 2S pump was compared with the 1S-B100 by using diluted goat blood samples with three different hematocrit values. The results showed that the hemolysis index of the 2S pump, regarded as a total hemolysis index of both stage axial flow pumps, was less than those of the single stage axial flow pumps at all hematocrit values.

Animals↗

PubMedDate not supplied

Surgical treatment for advanced gastric cancer.

BACKGROUND/AIMS: We herein report on the clinicopathological factors related to the unresectability of far advanced gastric cancer and the prognostic effect of gastrectomy on these cases. MATERIAL AND METHODS: There are four main prognostic factors for advanced gastric cancer including 1) peritoneal dissemination, 2) hepatic metastasis, 3) lymph node involvement and 4) invasion to adjacent organs. RESULTS: The rate of unresectability was high in the cases demonstrating both histologically undifferentiated type cancer and cancers located in the lower third of the stomach. It was difficult to resect the main tumor based on an increase in the factors regulating the macroscopical stage. The rate of unresectability tended to be higher in cancers with peritoneal dissemination or invasion to adjacent organs. The pancreas was the most frequently invaded organ. accounting for the unresectability of the disease. The prognosis for cases with unresected gastric cancers was poor and all died within 2 years of the operation. In addition, the prognosis for cases with Stage IV gastric cancer, demonstrating either 1 or 2 factors, improved after gastrectomy while no such improvement was seen in cases with 3 or 4 factors. CONCLUSIONS: To improve prognosis, gastrectomy should be performed when a patient has far advanced gastric cancer but only demonstrates 1 or 2 of the above 4 factors.

Adult↗

PubMedDate not supplied

Clinicopathological features of lymph node metastasis in early gastric cancer.

From 1979 through 1992, 482 cases with solitary early gastric cancer were resected in the Department of Surgery of the National Kyushu Medical Center Hospital. Among the 482 cases, the incidence of lymph node metastasis was 10.0% (48/482). The features of lymph node metastasis were studied while taking into account the combination of clinicopathological findings of the gastric cancer. Lymph node metastasis was rare in both the differentiated type mucosal cancers and submucosal cancers measuring 20 mm or smaller in size without depression. From these results, for early gastric cancer with the above-mentioned characteristics, either endoscopic therapy or local resection without lymph node dissection is considered to be sufficient treatment to obtain a favorable outcome.

Adult↗