Biomedical subjects

H Honda

Publications and source records attributed to H Honda.

At least 289 records · Page 16Linked to original sources

PubMed1994

Noninvasive measurement of left ventricular myocardial elasticity.

We examined Advani and Lee's equation (ALeq) and a dimension analysis-derived equation (DAeq), both of which treat vibration of the elastic spherical shell and are able to estimate elasticity of the shell noninvasively when the sizes and eigen-frequency are provided. We confirmed that ALeq was numerically identical to DAeq and that both equations gave the precise elasticity of the silicone shell. Then we estimated left ventricular (LV) myocardial elasticity noninvasively at the moment of the first heart sound emission (1HS) in 25 healthy subjects and 14 hypertrophic cardiomyopathy (HCM) patients, based on the LV eigen-frequency detected by an intraesophageal miniature vibration sensor. HCM patients had a higher mean value of LV myocardial elasticity at 1HS than healthy subjects [102.3 +/- 33.4 vs. 70.7 +/- 24.4 kPa, P < 0.01 (Pa = N/m2 = 10 dyn/cm2)]. We thereby demonstrated the possibility of a noninvasive estimate of myocardial elasticity.

Adult↗

PubMed1994

Mathematical model of the effects of mechanical vibration on crossbridge kinetics in cardiac muscle.

We previously reported that the application of an external mechanical vibration to the epicardial surface caused a vibration-induced-depression (VID) of left ventricular (LV) function. The magnitude of the VID of peak LV pressure increased as either the amplitude or the frequency of the vibration increased. When LV contractility was altered by the administration of propranolol or by continuous infusion of dobutamine, the magnitude of the VID of peak LV pressure was inversely correlated with LV contractility. These characteristics were observed in open-chest and isolated canine preparations. In the present study, we constructed a muscle model to obtain a theoretical explanation for these effects. This model was first proposed by Gray, Gonda and Cheung, and has been extended in this report to explain twitch tension. This new, improved model is able to explain twitch tension and the effects of external vibration on twitch contraction semi-quantitatively. The successful predictions of the this model support the idea that external vibration directly affects contractile protein and modulates crossbridge kinetics.

Adenosine Triphosphatases↗

PubMed1994

[Acidified aspirin-induced gastric lesion in rats with hepatic cirrhosis produced by N-nitrosodiethylamine or carbon tetrachloride. Effect of aldioxa on gastric lesions].

Gastric lesion was induced by the oral administration of acidified aspirin in rats with hepatic cirrhosis produced by N-nitrosodiethylamine (NDA) or carbon tetrachloride (CCl4). Gastric lesion by acidified aspirin was aggravated in NDA-induced cirrhosis, but not in CCl4-cirrhotic rats. To clarify this difference in the susceptibility of the gastric mucosa, gastric mucosal blood flow and gastric emptying were measured by the hydrogen gas clearance method and beads method, respectively. Gastric mucosal blood flow was lower and gastric emptying was significantly delayed in NDA-induced cirrhotic rats as compared with the controls, but not in CCl4-induced cirrhotic rats. Gastric mucosal blood flow in NDA-induced cirrhotic rats was significantly decreased by the oral administration of acidified aspirin as compared with the controls. Aldioxa dose-dependently inhibited the gastric lesion formation by acidified aspirin and inhibited the decrease of gastric mucosal blood flow in NDA-induced cirrhotic rats. These results suggest that aggravation of gastric lesion induced by acidified aspirin in NDA-induced cirrhotic rats would be due to the decrease of gastric mucosal blood flow and delay of gastric emptying. In addition, aldioxa showed a protective effect against gastric lesions induced by acidified aspirin in NDA-induced cirrhotic rats, suggesting that this compound would have an inhibitory effect on gastric lesions that are accompanied by hepatic cirrhosis.

Allantoin↗

PubMed1994

A new technique for performing total thymectomy on rabbits.

Sixty-one Japanese white rabbits underwent total thymectomies. Eight of the animals died of intraoperative hemorrhage or respiratory failure, and twelve died of postoperative hypovolemia, dehydration, malnutrition or wound infections. Forty-one rabbits survived and were used as a total thymectomy model. The whole procedure of our technique is described in detail so that even those with no experience of performing thymectomies can follow it. Some tactics especially how to deal with the thymic vessels and the pleurae, are key points. Our technique permits safe and perfect total thymectomies to be carried out on rabbits.

Animals↗

PubMed1994

Possible thyroidal involvement in a case of Fabry disease.

Endocrinological evaluations of a 48-year-old man with Fabry disease revealed low levels of serum thyroid hormones and high levels of serum thyrotropin (TSH), indicating that the patient had primary hypothyroidism. Also, an exaggerated growth hormone (GH) response to hypoglycemic stimuli was observed. Thin layer chromatography of the lipid extract of the thyroid gland obtained by biopsy demonstrated marked accumulation of ceramide trihexoside (CTH) and ceramide dihexoside (CDH). These findings strongly suggest that thyroid hypofunction and hypothalamic dysfunction could be involved in Fabry disease.

Fabry Disease↗

PubMed1994

Diagnosis of inflammatory pseudotumor of the liver: value of CT.

OBJECTIVE: Inflammatory pseudotumor of the liver is a localized mass consisting of a fibrous stroma and chronic inflammatory infiltrate without anaplasia. Diagnosis of this rare disease is important to avoid surgery. The purpose of this study was to determine if CT is useful in the diagnosis of this lesion. SUBJECTS AND METHODS: CT scans of nine patients with a proved diagnosis of inflammatory pseudotumor of the liver were reviewed. Diagnosis was made by the surgical resection in three patients and by percutaneous biopsy in six patients. Six patients had symptoms and laboratory data suggesting active inflammation caused by the pseudotumor. The remaining three patients were asymptomatic. CT scans were performed with IV administration of the contrast material; scans were obtained in the portal venous and delayed phases in six patients and in the delayed phase in three patients. CT scans were analyzed for the number and size of the hepatic masses, and the degree and pattern of contrast enhancement on portal venous phase and delayed-phase images. RESULTS: Eight patients had a solitary hepatic mass, and one patient had two masses on the CT scan. The average size of the masses in the symptomatic patients (8.3 cm) was larger than that in the asymptomatic group (3.6 cm). CT scans in the portal venous phase showed a variable degree of contrast enhancement (seven masses). At least a part of seven masses, six of which were in symptomatic patients, showed greater contrast enhancement on delayed-phase CT scans than on the normal liver parenchyma. No constant pattern of enhancement was observed on delayed-phase CT scans in asymptomatic patients. CONCLUSION: Inflammatory pseudotumor of the liver should be included in a differential diagnosis in patients with a hepatic mass on a CT scan, especially when patients are symptomatic and the mass is fairly large and solitary showing contrast enhancement greater than that of liver parenchyma on delayed-phase CT scans. Percutaneous biopsy should be performed to obtain a histologic confirmation.

Adolescent↗

PubMed1994

Prevalence of HCV-antibodies and HCV-RNA in donor blood in Tokushima Prefecture.

The incidence of C100-3 among the blood specimens qualified for transfusion according to the conventional criteria was 1.1%. The incidence of C100-3 in donor blood in Tokushima Prefecture is not significantly different from that reported for all Japan. Of the donors positive for the conventional screening test and C100-3, 73.6% showed high ALT levels. For all antibodies, the incidence of HCV-RNA was very low in the donors positive for a single antibody, but was high in those positive for multiple antibodies. All of the donors showing the 3 antibodies were positive for HCV-RNA. While a test for multiple antibodies is thought to be effective for the screening of HCV, more blood needs to be discarded, having a serious cost-performance problem. The O.D. value for C100-3 and the 2nd antibody seem to be useful reference value for antibody titers.

Adolescent↗

PubMed1994

Serologic, virologic, and histologic characteristics of chronic phase hepatitis C virus disease in children infected by transfusion.

OBJECTIVE: We studied the time course of hepatic dysfunction, seropositivity to hepatitis C virus (HCV) antibodies, viremia, and histologic evidence of hepatic injury to evaluate the course of HCV infection in children infected by blood transfusion. PATIENTS AND METHODS: Twenty-nine patients (ages 4 to 18 years) who underwent open-heart surgeries for congenital heart disease were grouped into three categories based on alterations in serum alanine aminotransferase (ALT) levels: Group A, acute infection; Group B, subacute infection; and Group C, chronic infection. RESULTS: In Group C, all 13 patients had detectable HCV RNA in serum. In contrast, all patients in Group A had no detectable HCV RNA: In Group B, one of nine patients had detectable HCV RNA and two of four patients examined had persistent chronic hepatitis by histologic criteria. Antibodies directed against C100-3 antigen or core-antigen were more useful than second-generation HCV antibody assays in determining the relationship between viremia and immunologic response. Infection with HCV genotype II and the presence of higher HCV RNA copy numbers were associated with histologic evidence of hepatic damage. CONCLUSION: An abnormal ALT value is frequently associated with viremia, and biochemically resolved acute infection reflects clearance of HCV. However, a normal ALT does not always reflect an absence of hepatocyte damage and HCV replication in patients with subacute disease. The measures outlined in this study are useful indicators of disease activity during the chronic

Acute Disease↗

PubMed1994

[Study of 5'-DFUR treatment as postoperative adjuvant chemotherapy for stomach and colorectal cancer. Tokai GATS Group (pilot study)].

In order to study preliminary the safety of 5'-DFUR treatment as postoperative adjuvant therapy, intermittent and continuous treatment regimens were administered to patients undergoing curative resection of carcinomas of the stomach and the colorectum. Two treatment schedules were employed: 5'-DFUR was either given continuously in a daily oral dose of 600 mg/patient (continuous group) or for 2 weeks in a daily oral dose of 1,200 mg/patient followed by 2 weeks of no treatment (intermittent group). Twenty-one stomach cancer patients and 34 colorectal cancer patients were registered in the study. The rates of adverse drug reactions in the patients who completed treatment were 20.0% (2/10) in the continuous group and 50.0% (4/8) in the intermittent group of gastric cancer patients, and 16.6% (2/12) in the continuous group and 17.6% (3/17) in the intermittent group of colorectal cancer patients. The main adverse drug reactions were gastrointestinal symptoms. The incidence of diarrhea, a problematic side effect of 5'-DFUR, was 4.5% (1/22) in the continuous group and 12.0% (3/25) in the intermittent group. There were no statistically significant differences between the continuous group and the intermittent group in regard to the incidence of adverse drug reactions and survival rate. In addition, as there were no serious adverse drug reactions, both treatment regimens were demonstrated to be highly safe when administered as postoperative adjuvant therapy.

Administration, Oral↗

PubMed1993

A comparative study of hepatic resection and transcatheter arterial embolization for the treatment of primary hepatocellular carcinoma.

BACKGROUND: Because transcatheter arterial embolization (TAE) has been shown to be effective in patients with unresectable hepatocellular carcinoma (HCC), the question arises whether TAE has an equivalent or superior effect on resectable HCC compared with surgery. To clarify this point, the authors compared the therapeutic results achieved by surgery and TAE in patients with early-stage HCC and well-preserved liver function, who were independently treated by two different policies in two separate departments of the same university hospital during the same period. METHODS: From 1983 to 1987, 67 patients with HCC underwent hepatic resection at the Department of Surgery of Kyushu University Hospital. During the same period, TAE was the treatment of first choice for HCC, and surgical resection was not chosen in the Department of Internal Medicine of the hospital. TAE was done in 68 patients, who were evaluated blindly in terms of liver function reserve and roentgenographic resectability of the tumor. Among the 68 patients, 20 were thought to have anatomically and functionally resectable disease. The therapeutic results obtained in the two groups were compared. RESULTS: The 1-year, 3-year, and 5-year cumulative survival rates for 67 patients undergoing surgery, including one operative death and four hospital deaths, were 89.1%, 74.6%, and 54.6%, respectively. However, the rates were 90.0%, 50.0%, and 17.5%, respectively, for the 20 patients treated with TAE; these differences were statistically significant (P < 0.05). CONCLUSIONS: Surgery can offer more favorable results in patients with early-stage HCC compared with TAE.

Carcinoma, Hepatocellular↗

PubMed1993

Inhibitory action of 4-aminopyridine on Ca(2+)-ATPase of the mammalian sarcoplasmic reticulum.

In the isolated guinea pig diaphragm muscle, 4-aminopyridine (4-AP) elicited a marked potentiation of twitch contraction evoked by direct electrical stimuli. Although tetraethylammonium (TEA) and charybdotoxin only slightly potentiated twitch contraction, 4-AP, but not TEA, also augmented a contractile response to caffeine. These effects of 4-AP on muscle contraction could not be interpreted by a simple inhibition of potassium channels on the plasma membrane. In the fragmented sarcoplasmic reticulum (SR) prepared from the guinea pig psoas muscle, 4-AP inhibited the ATP-driven Ca2+ uptake from the extravesicular medium. Furthermore, 4-AP at concentrations less than 10 mM elicited a selective inhibition of Ca(2+)-activated SR ATPase in a competitive manner against the Ca2+ concentration of the medium and 10 mM 4-AP showed the unsurmountable inhibition. 4-AP at 30 mM apparently inhibited activities of other ATPases such as Na+,K+- and myosin ATPases. In contrast, other potassium channel blockers such as TEA, apamin, charybdotoxin, and glibenclamide did not inhibit the SR function. These results suggest that, although the specific concentration range is rather small, 4-AP elicits an inhibition of SR Ca(2+)-pumping activity, leading to the marked potentiation of muscle contractile responses to electrical stimuli and caffeine.

4-Aminopyridine↗

PubMed1993

Appearance of PLP mRNA in specific regions of the developing rat lumbosacral spinal cord as revealed by in situ hybridization.

The capacity of specific regions and fiber tracts of developing rat lumbosacral spinal cord to express proteolipid protein (PLP) mRNA was examined using in situ hybridization. PLP mRNA was undetectable at Day 18 postfertilization but present in the white matter by Postnatal Day 0 (P0). Initially, levels of PLP mRNA were higher in ventral than in dorsal funiculi. Hybridization signal was observed in the corticospinal tract by P10. Appearance of PLP message in gray matter lagged several days behind that in white matter. The expression of PLP mRNA in gray matter rose between P10 and P40 and the abundance of PLP transcript remained high in white matter during the same period. In the adult spinal cord some oligodendrocytes in the Lissauer tract and in the posterior commissure expressed low levels of PLP mRNA, which was undetectable in the substantia gelatinosa. Comparing the time of emergence of PLP mRNA to the histological appearance of myelination gave evidence that the message is expressed in oligodendrocytes that are not many days away from myelin formation. These results provide new information on the topographic distribution of PLP mRNA during myelination of the rat spinal cord.

Animals↗

PubMed1993

Hepatocellular carcinoma: prospective assessments of the T-factor with CT, US, and MR imaging.

The capabilities of computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging were studied in order to determine the role of each of these noninvasive examinations for estimating the T-factor of hepatocellular carcinomas (HCCs). Fifty-one patients with surgically proven HCCs received CT (50 patients), US (46 patients), and MR (44 patients). The images of CT, US, and MR were prospectively evaluated for main tumor size, intrahepatic metastases, and vascular invasion, which compose the T-factor of HCC, and compared to pathological results. The sizes of the main tumor were estimated correctly by all examinations. For estimating intrahepatic metastases, US (74%) and MR (73%) were superior to CT (65%). For estimating portal invasion, CT (79%) was superior to US (70%) and MR (66%), because CT could demonstrate the segmental staining caused by portal invasion. The estimates of hepatic venous invasion were difficult during any of the examinations. We conclude that presurgical evaluations of the T-factor require the use of US and CT or MR and CT.

Aged↗

PubMed1993

A new type porous carrier and its application to culture of suspension cells.

A new type porous carrier was fabricated from a mixture of sodium alginate, bovine serum albumin and sodium bicarbonate. The porous space of the carrier is an assembly of void spaces. The carrier was successfully applied to the cultivation of suspension animal cells. In the culture, while both cells and carriers were held in suspension, the cells were entrapped hydrodynamically into the void spaces in the carriers. A culture of hybridoma cells using this carrier resulted in a cell density up to 5.7 x 10(7) cells per ml-carrier.

Alginates↗

PubMed1993

Postoperative MRI evaluation of anorectal malformations with clinical correlation.

Sixteen postoperative patients with anorectal malformation were evaluated by MRI, and the results compared with the clinical assessment. Patients were classified into three groups--good (group 1, n = 10), fair (group 2, n = 3) and poor (group 3, n = 3)--on the basis of Kelly's clinical score of incontinence. The degree of development of the puborectalis and external sphincter muscles and the levator hammock was evaluated on MRI in comparison with patients without anorectal disease. The proportions of fair or poor development of the muscles were 37% in group 1,22% in group 2 and 67% in group 3. Although fair or poor development of the muscles was seen more frequently in group 3, there was no statistically significant difference between groups. However, poorly developed muscles were seen only in patients with fair or poor clinical scores. The difference in the anorectal angle measured on sagittal MRI images between patients in group 1 and groups 2 or 3 was significant. Our study indicates that MRI evaluation based solely on muscle development can be misleading, and measurement of the anorectal angle should be included in the MRI evaluation.

Abnormalities, Multiple↗

PubMed1993

Estimation of left ventricular myocardial elasticity and viscosity by a thick-walled spherical model.

The authors measured the transfer function (TF) of the left ventricle (LV) in an isolated canine preparation. Here TF indicates the ratio of induced vibration in LV to input vibration when an external mechanical oscillation is applied. TF had a single peak the frequency of which changed from 40 Hz to 80 Hz when LV pressure (LVP) increased from 6 mm Hg to 96 mm Hg. A mathematical model was formulated to estimate the viscoelasticity of the spherical shell. This model was constructed of the material points, elastic components which connected all the material points, and viscous components placed in series with elastic components. Theoretical TF can be computed if the viscoelastic values are given. The value of viscoelasticity at which the theoretical TF best fitted the experimental TF was considered to be the viscoelasticity of the model. The validity of this approach was verified using a silicone spherical shell. The estimated myocardial elasticity was 40 kPa when LVP was 6 mm Hg, 160-170 kPa when LVP was 96 mm Hg and was approximately proportional to LVP, whereas viscosity showed small change. The inclination of elasticity was consistent with previous reports. These results proved that myocardial elasticity can be estimated by analysing the transfer function of the left ventricle.

Animals↗

PubMed1993

Gastric vasodilator and motor responses to splanchnic stimulation and tachykinins in the dog.

1. Gastric blood flow and motor responses to greater splanchnic nerve stimulation and intra-arterial injection of tachykinins were studied in anaesthetized dogs. 2. Splanchnic nerve stimulation (40 V, 10 Hz) with pulse durations of 0.05 and 1 msec caused a gastric relaxation and contraction, respectively. Both types of stimulation produced a decrease followed by an increase in blood flow. The responses to stimulation with a pulse duration of 0.05 msec were inhibited by hexamethonium. 3. After treatment with hexamethonium, stimulation with 1 msec caused frequency-dependent gastric contraction and vasodilation. Both responses had two components, sensitive and resistant to atropine. 4. Intra-arterial injection of substance P (SP), neurokinin A (NKA), neurokinin B (NKB), physalaemin (PHY) or eledoisin (ELE) elicited dose-dependent gastric contraction and vasodilation. The order of potency for contraction was SP = PHY = ELE = NKA >> NKB and that for vasodilation was SP = PHY > ELE > NKA > NKB. 5. Atropine partly inhibited the tachykinin-induced gastric contraction but not gastric vasodilation. Spantide partly inhibited the atropine-resistant vasodilation but not contraction in response to splanchnic nerve stimulation and SP. 6. It is concluded that splanchnic nerve stimulation produced cholinergic and SPergic vasodilation after ganglionic blockade in the dog stomach.

Animals↗

PubMed1993

Ca(2+)-dependent aggregation of rabbit platelets induced by maitotoxin, a potent marine toxin, isolated from a dinoflagellate.

1. Administration of maitotoxin (MTX), a dinoflagellate toxin, caused aggregation of rabbit washed platelets. The cytosolic Ca2+ concentration ([Ca2+]i), measured by fura-2 fluorescence technique, was also increased by the presence of MTX. Rates of aggregation response and [Ca2+]i-increase were dependent on tested concentrations (3-100 ng ml-1) of the toxin. 2. The MTX-induced platelet aggregation and [Ca2+]i-increase were totally abolished in a Ca(2+)-free solution. The successive administration of Ca2+ in the presence of MTX elicited the aggregation and increase in [Ca2+]i. 3. Ba2+ was capable of substituting for Ca2+ in the MTX-induced platelet aggregation. In the presence of external Ca2+, transition metals, Co2+, Cd2+ and Ni2+, inhibited the aggregation response to MTX. 4. Organic calcium antagonists (verapamil and nifedipine) as well as a cyclo-oxygenase-inhibitor (aspirin) did not apparently inhibit the aggregation response to MTX, except for a high concentration (10(-5) M) of verapamil, while procaine (10 mM) reduced the rate of platelet aggregation. 5. MTX also elicited a release of ATP from platelets, which was abolished in the absence of external Ca2+. 6. In contrast, thrombin 0.5 unit ml-1 could elicit platelet shape change, [Ca2+]i-increase and ATP-release in the absence of external Ca2+. 7. These results suggest that the MTX-induced platelet activation is caused by an enhanced Ca(2+)-influx presumably through voltage-independent Ca2+ channels on the plasma membrane.

Adenosine Triphosphate↗