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Biomedical subjects

T Wakatsuki

Publications and source records attributed to T Wakatsuki.

At least 91 records · Page 5Linked to original sources
PubMed1992

Single moving dipole obtained from magnetic field of the heart in patients with left ventricular hypertrophy.

Magnetocardiograms (MCGs) were recorded by means of a second-derivative SQUID (superconducting quantum interference device) magnetometer in 20 normal subjects and 28 patients with left ventricular overload to analyze the activation sequence of the heart and amplitude of estimated current source. In the normal subjects, the dipole was directed to the left and gradually superiorly 40 ms after the beginning of the QRS wave mainly due to the activation of the left ventricle. In the patients with hypertension, the direction and location of the dipoles were similar to those of the normal subjects, but their dipole moments were increased. In the patients with mitral regurgitation, the dipoles of late QRS were directed more inferiorly than in the normal subjects and their amplitude was increased. In the patients with aortic valve disease, the amplitude of the dipoles was increased markedly and their location was deviated more to the left than the dipoles of the normal subjects. We established the criterion for diagnosis of LVO from the dipole moment of 50 ms of 3.13 x 10(-3) A or more. The sensitivity of this criterion is significantly higher in the diagnosis of left ventricular overload than the electrocardiogram (ECG). The present study shows that the moving dipole method is useful to determine the increased electromotive force in patients with left ventricular overload and that sensitivity in diagnosis of left ventricular overload is increased.

Aortic Valve Insufficiency↗
PubMed1992

Effects of low culture temperature on the induction of hsp70 mRNA and the accumulation of hsp70 and hsp105 in mouse FM3A cells.

We have shown that heat shock does not induce the synthesis of hsp70 in FM3A cells maintained at a low culture temperature of 33 degrees C although it does so in cells maintained at 37 degrees C [T. Hatayama et al. (1991) Biochem. Int. 24, 467-474]. In this paper, we show that FM3A cells maintained at 37 degrees C produced hsp70 mRNA during continuous heating at 42 degrees C or during postincubation at either 37 or 33 degrees C after being heated at 45 degrees C for 15 min, whereas cells maintained at 33 degrees C did not produce hsp70 mRNA during continuous heating at 37, 39, 42, or 45 degrees C, or during postincubation after being heated at any temperature. Thus the lack of hsp70 synthesis in cells maintained at 33 degrees C seemed to be due to the absence of hsp70 mRNA induction. Also, hsp70 was accumulated in cells maintained at 37 degrees C during continuous heating at 42 degrees C and during postincubation at 37 degrees C after heat shock at 45 degrees C, but not during postincubation at 33 degrees C. The cellular level of the constitutive hsp73 as well as the mRNA level were both similar in cells maintained at 33 and 37 degrees C. On the other hand, the cellular level of the constitutive hsp105 in cells maintained at 33 degrees C was only half of that in cells maintained at 37 degrees C. These hsp105 levels increased significantly in both types of cells after continuous heating at 39 degrees C. These findings indicate that the culture temperature affects not only the induction of hsp70 mRNA but also the accumulation of hsp70 and hsp105 in the cells.

Animals↗
PubMed1992

Vasopressin modulates K(+)-channel activities of cultured smooth muscle cells from porcine coronary artery.

The ATP-sensitive K+ channel (KATP channel) and the Ca(2+)-activated K+ channel (KCa channel) were active in cell-attached and excised inside-out patch configurations in cultured smooth muscle cells of the porcine coronary artery. Vasopressin activated the KCa channel (240 pS) when it was applied in the bath in the cell-attached patch mode presumably because of an increase in intracellular Ca2+, but it had no direct effect on the KCa channel. However, vasopressin directly blocked the KATP channel from outside the cell membranes in a concentration-dependent manner in both outside-out and cell-attached patch configurations; the K(+)-channel opener, nicorandil, reversed this effect. The KATP channel (30 pS) was highly active in the intact cell-attached patch configuration when the pipette contained a physiological concentration of Ca2+, suggesting that this channel may control the resting membrane potential. (The block might produce depolarization of the cells and might result in the contraction of smooth muscle cells.) These observations suggest that the KATP channel may play a role, at least in part, in controlling the contraction of smooth muscle cells of the coronary artery and that the control of vascular tone by vasopressin may be related to its ability to block the KATP channel.

Adenosine Triphosphate↗
PubMed1992

Endothelin blocks ATP-sensitive K+ channels and depolarizes smooth muscle cells of porcine coronary artery.

ATP-sensitive K+ channels with a conductance of 30 pS in smooth muscle cells of porcine coronary artery were found to be highly active in the intact cell-attached patch configuration when the pipette contained a physiological concentration of Ca2+ (greater than 10(-4) M). In the inside-out configuration, these channels were activated by extracellular Ca2+ and blocked by cytosolic ATP and glibenclamide. Endothelin applied to the pipette specifically blocked these channels in a concentration-dependent manner in the cell-attached configuration (half-maximal inhibition, 1.3 x 10(-9) M). A K+ channel opener, nicorandil, activated these channels even in the presence of 10(-8) M endothelin. In the whole-cell current-clamp method, the cell membrane was depolarized by endothelin and then repolarized by nicorandil. The membrane depolarization is closely related to contraction of smooth muscle cells. These results suggest that the ATP-sensitive K+ channels are important in controlling the vascular tone of the coronary artery and that endothelin can increase vascular tone by blocking these channels.

Adenosine Triphosphate↗
PubMed1992

Production of phytochelatins in Polygonum cuspidatum on exposure to copper but not to zinc.

We studied cellular resistance to copper of plant cells Polygonum cuspidatum. When callus of P. cuspidatum was incubated on medium containing 100 microM cupric sulfate, the callus grew as well as the control callus did. The copper content of the callus, however, was elevated to a similar level of the medium. When cell extracts of callus exposed to 100 microM cupric sulfate were fractionated by gel filtration chromatography, a specific copper peak was eluted at the region of molecular weights between 4000 and 1000. Since an appearance of the copper-containing materials was inhibited by buthionine sulfoximine and the partially purified copper-containing materials contained only three amino acids: glutamic acid, glycine and cystine, the materials were supposed to be gamma-glutamyl peptides phytochelatins. Callus of P. cuspidatum synthesized phytochelatins from 50 microM cupric sulfate and maximally at 100-150 microM cupric sulfate. When induction of phytochelatins by another heavy metal, zinc, was analyzed, the callus, however, did not synthesize phytochelatins on exposure to zinc sulfate up to 1 mM. These findings suggested that phytochelatins were required for resistance to copper but probably not to zinc in the plant cells.

Cells, Cultured↗
PubMed1992

Long-term histologic follow-up study of alcoholic liver disease.

Forty Japanese patients with alcoholic liver disease (nonspecific change, 9; fatty liver, 5; hepatic fibrosis, 4; chronic hepatitis, 12; alcoholic hepatitis, 5; liver cirrhosis, 5) were followed for 3-17 yr (average 8 yr) with repeated liver biopsies (2-5 times; average 2.5 times) at intervals of more than 3 yr. All of the patients continued to consume alcohol during this observation period. Five out of 12 patients with chronic hepatitis and 2 of 5 patients with alcoholic hepatitis eventually progressed to cirrhosis, while none of the 4 patients with hepatic fibrosis became cirrhotic. Anti-hepatitis C virus antibody was positive in 2 patients with liver cirrhosis among 12 patients whose sera were available. Two patients with cirrhosis died of hepatic failure and one patient died of hepatocellular carcinoma. These data suggest that the long-term prognosis of alcoholic liver disease is not necessarily poor, but patients with chronic hepatitis or alcoholic hepatitis can be at risk of progression to cirrhosis.

Adult↗
PubMed1991

Different induction of 70,000-Da heat shock protein and metallothionein in HeLa cells by copper.

To clarify the physiological roles of heat shock proteins induced by copper, we studied the synthesis of these proteins and metallothionein, as well as the level and nature of copper incorporated into HeLa cells. Incubation in medium containing 200 microM cupric sulfate and above induced the synthesis of 70,000-Da heat shock protein (hsp70) in these cells. However, the synthesis of hsp70 did not increase in the presence of less than 200 microM cupric sulfate. On the other hand, the synthesis of metallothionein increased due to 100 microM cupric sulfate. The uptake of copper into the cells depended on the cupric sulfate concentration in the medium. To analyze the nature of the intracellular copper, cell extracts were separated by gel filtration chromatography into three fractions: the high molecular weight, metallothionein, and low molecular weight fractions. No copper was found in the low molecular weight fraction of control cells, but appeared distinctly at 200 microM cupric sulfate and above. Copper in the high molecular weight fraction also began to increase at 200 microM cupric sulfate and above, whereas in the metallothionein fraction it began to increase even at 50 to 100 microM cupric sulfate. Furthermore, inhibition of cell growth was also observed at 200 microM cupric sulfate and above but not at 100 microM and below.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Division↗
PubMed1991

Mandibular alveolar ridge extension method using a surgical splint with porous hydroxyapatite (HAP) particles.

The mandibular alveolar ridge extension method is a surgical technique to extend the alveolar ridge up to the required level. Using a surgical splint prepared to meet the clinical requirements establishes the desirable alveolar ridge extension with porous hydroxyapatite (HAP) particles. Before the operation, a working cast of the extremely resorpted mandibular alveolar ridge is remodeled into its desired shape with paraffin wax, and the extended surgical splint is cured by clear acrylic resin. After subperiosteal tunnel dissection, the surgical splint is fixed to the mandible with circummandibular ligatures; then the HAP particles are injected into the tunnel. After healing, a treatment denture is cured between the artificial dentition and the surgical splint with self curing resin. In this method, the HAP particles are injected into the subperiosteal tunnel that is created between the surface of alveolar bone and the periosteum covered by the surgical splint; the migration of HAP particles completes the extension of the alveoral ridge.

Alveolar Ridge Augmentation↗
PubMed1991

Induction of heat shock protein and thermal sensitivity of mammalian cells maintained at low culture temperature.

Effects of low culture temperature on the induction of heat shock proteins in FM3A cells by a heat shock and on the thermal sensitivity of the cells were examined. FM3A cells maintained at 33 degrees C could not induce hsp70 during continuous heating or after a short heat shock at either 39, 42, or 45 degrees C, although FM3A cells maintained at a normal culture temperature of 37 degrees C can induce the synthesis of hsp70. Furthermore, the cells maintained at 33 degrees C were more sensitive to the subsequent heat shock than the cells maintained at 37 degrees C. Thus, the culture temperature of the mammalian cells may be an important factor for the induction of hsp70, and hsp70 may play an important role to protect or repair the thermal damage of cells.

Animals↗
PubMed1991

Effects of nitroglycerin on ATP-induced Ca(++)-mobilization, Ca(++)-activated K channels and contraction of cultured smooth muscle cells of porcine coronary artery.

Extracellular application of ATP transiently increases the cytosolic-free Ca++ concentration ([Ca++]i) in cultured smooth muscle cells of porcine coronary artery, and this activates large conductance Ca(++)-activated K (Kca) channels. In the present study effects of nitroglycerin (NG) and 4-aminopyridine (4-AP) on [Ca++]; and contraction were studied. 4-AP blocked Kca channels and enhanced the rise of [Ca++]i with oscillation, which led to contraction of the cells. NG activated the Kca channels of 300 picosiemens and inhibited 4-AP-induced contraction and oscillation of [Ca++]i. These results suggest that the vasorelaxant effect of NG involves hyperpolarization of the cell membrane by activating the Kca channels. NG also cause rapid decrease of [Ca++]i during the Ca(++)-mobilization by ATP in Ca-free solution. Similar effects were observed with cyclic GMP, suggesting that the effects of NG on the Kca channels and [Ca++]i were mediated by cyclic GMP.

4-Aminopyridine↗
PubMed1989

[Effects of prophylactic intraportal chemotherapy on liver function, blood profile and survival in patients with colo-rectal cancer].

Postoperative intraportal anti-cancer chemotherapy was used for 51 patients with curatively resected colorectal cancer who were selected in the randomized controlled study to evaluate its inhibitory effect on liver metastasis from colo-rectal cancer. In cases of intraportal chemotherapy, 30 mg of Mitomycin-C (in 3 doses) and 5 mg/kg (B.W.)/day (1985-1986) or 3 mg/kg/day (1987-1988) of 5-FU was injected through the catheter inserted into the portal vein during postoperative 14 days. In cases of the control group (58 patients), the same doses of the drugs were injected into the peripheral vein during the same term. Six patients with recurrences were observed in the intraportal chemotherapy group, and 3 of them had liver metastases. In the control group, more liver metastases were observed (5 of 7 recurrences were liver metastases). Intraportally injected 5 mg/kg/day of 5-FU slightly disturbed the liver function. The averages of the serum GOT, GPT and gamma-GTP level of these cases were higher than those of the control cases. Three mg/kg/day of intraportally injected 5-FU had no influence on the liver function. There were no differences in the incidence of leukocytopenia or thrombocytopenia between the two groups.

Aged↗
PubMed1989

[Physicochemical characteristics of new reinforcement ceramic implant].

Investigation of the physicochemical characteristics of reinforcement ceramic implant materials which have needle crystal produced the following results. 1. Simple diopside and hydroxyapatite with diopside have enough dynamic intensity of both the implant in point of bending intensity and the breaking toughness. 2. Simple diopside and hydroxyapatite with diopside go well as biomechanics because of their Young's modulus being close to the surrounding bone. 3. Diopside in pseudo-body fluid developed hydroxyapatite on surface like bioglass, and this resulted in high possibility of direct bond with bone. 4. The results of this study indicate that the diopside and hydroxyapatite with diopside have enough dynamic intensity and are bioactive dental implant materials.

Ceramics↗
PubMed1988

Prophylactic therapy for peritoneal recurrence of gastric cancer by continuous hyperthermic peritoneal perfusion with mitomycin C.

Continuous hyperthermic peritoneal perfusion (CHPP) with a solution that contains mitomycin C (CHPP-M) has been clinically introduced as a prophylactic treatment for peritoneal recurrence of gastric cancer with serosal invasion. Two studies, each with a treated and a control group, were performed. In the historical control study the postoperative 3-year survival rate of patients (73.7%) in the treated group (n = 38) was significantly higher than the survival rate (52.7%) of those in the control group (n = 55) (P less than 0.04). In the random control study the survival rate (83%) of patients in the treated group (n = 26) was also higher than that (67.3%) of those in the control group (n = 21) in the 30 months that followed gastric surgery. However, there was no significant difference. In the historical control study with respect to the postoperative complications, anastomotic leak was observed in 8.5% of patients who were given CHPP-M and 12.8% patients who did not have CHPP-M. In the random control study anastomotic leak was observed in 3.1% of patients who had CHPP-M and 7.1% of patients who did not have CHPP-M. The incidence of adhesive ileus in patients having CHPP-M did not increase in historical or random control groups. Postoperative prolonged intestinal paresis or chemical peritonitis were not induced by CHPP-M. These results indicate that CHPP-M is a simple, safe, and readily available prophylactic therapy for peritoneal recurrence that may follow gastric cancer surgery.

Adult↗
PubMed1988

[Hepatic arterial chemotherapy combined with hyperthermia or arterial embolization in unresectable liver tumor].

Fifty-four patients with unresectable malignant liver tumors (14 of hepatocellular carcinoma, 40 of metastasis to the liver from gastric or colo-rectal cancer) were treated with intra-hepato-arterial (IHA) injections of cis-diamminedichloroplatinum (II) (CDDP) plus 5-fluorouracil (5-FU). In 32 of the patients, the liver tumors were detected synchronously with the diagnosis of the primary cancers, which were resected palliatively. Therapeutic schedules consisted of bolus injections of CDDP (50 mg/body/week) and 5-FU (250 mg/body/day) [Regimen I], and CDDP (50 mg/body/10-14 days) and 5-FU (100 mg/body/day) [Regimen II]. In 48 patients treated with IHA chemotherapy only, a partial response (PR) was obtained in 6 of 14 (43%) evaluable patients for Regimen I and in 11 of 30 (37%) patients for Regimen II. The dose-limiting factor for treatment with CDDP was bone marrow toxicity, but this toxicity was remarkably alleviated in Regimen II without any decrease in antitumor effectiveness. In 13 patients, other modalities, such as total-body hyperthermia (4 patients), radiofrequency capacitive local hyperthermia (5), and temporary arterial embolization (4), were combined with IHA chemotherapy. PR was obtained in 7 of 13 (54%) patients with the combined therapy. This combined therapy was efficacious in 7 patients in whom no desired results were obtained by IHA chemotherapy only. The survival rate was 50% at 12 months. IHA chemotherapy with CDDP plus 5-FU, especially when according to Regimen II, appears to be a strongly recommended strategy for treatment of unresected primary or metastatic liver tumor. Further, addition of the hyperthermia or the arterial embolization might enhance the antitumor effect of IHA chemotherapy.

Aged↗
PubMed1987

Carcinoembryonic antigen in gastric cancer patients.

Carcinoembryonic antigen (CEA) levels were determined in 252 gastric cancer patients. In patients with resectable cancer, the preoperative CEA values and CEA positivity rates were 2.4 +/- 1.5 ng/ml and 7.7% for stage I, 24.9 +/- 72.0 ng/ml and 10.0% for stage II, 21.6 +/- 84.1 ng/ml and 17.9% for stage III, and 6.3 +/- 8.4 ng/ml and 27.1% for stage IV cancers, respectively. In patients with nonresectable cancers, the CEA value was 83.0 +/- 235.5 ng/ml, the CEA positivity rate was 47.8%. Overall, of 252 patients with primary gastric cancer, 47(18.7%) were positive for CEA. In patients with cancer recurrence, the CEA value averaged 41.8 +/- 101.8 ng/ml, the positivity rate was 63%. This rate increased as the cancer stage increased; it was highest in gastric cancer patients with liver metastasis. In 4 of 13 patients with recurrence, an elevation in CEA was observed about 4.8 months before the clinical detection of cancer recurrence. Our results suggest that in gastric cancer patients, the preoperative and periodic postoperative assay of CEA levels has predictive value in determining cancer stage, progression and recurrence.

Carcinoembryonic Antigen↗