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Biomedical subjects

Y Hirano

Publications and source records attributed to Y Hirano.

At least 127 records · Page 7Linked to original sources
PubMed1997

Analyses of factors influencing participation in the cervical cancer screening programme in the community in Japan.

The association between the participation rates of cervical cancer screening programme and implementation methods, concerning data management, participant convenience, promoting participation, and payment, were analyzed. The data regarding the implementation methods were obtained in a nation-wide questionnaire survey. The relationship between the participation rates and implementation methods were assessed using the chi-square test and multiple logistic regression analyses. In small municipalities, with a population < 10,000 items concerning data management, enlisting the assistance of community organizations, fee exemption, and early morning screening were positively associated with the participation. In middle-sized municipalities, with the population 10,000-49,999, early morning screening, community organizations, items concerning data management, and sending out letters were positively associated with participation. Saturday/Sunday screening, community organizations, letters, and postcards were positively associated with the participation of the older group (> or = 50 years) in large municipalities with population of > 50,000. These results indicate that enlisting the assistance of community organizations and establishing a well-organized data management system are likely to improve participation regardless of municipality size. Other implementation methods must be selected taking into account factors such as municipality population size, as well as the age distribution and characteristics of the target population.

Adult↗
PubMed1997

Use of carbon dioxide microbubble-enhanced sonographic angiography for transcatheter arterial chemoembolization of hepatocellular carcinoma.

OBJECTIVE: Our objective was to determine the usefulness of sonographic angiography with carbon dioxide microbubbles during transcatheter arterial chemoembolization for hepatocellular carcinoma. SUBJECTS AND METHODS: Thirty-four patients with hepatocellular carcinoma underwent sonographic angiography during transcatheter arterial chemoembolization. Digital subtraction angiography failed to reveal tumors in 27 patients. Tumor stain became obscure on digital subtraction angiography after the catheter was inserted into distal branches in seven patients. Sonographic angiography was performed after injection of carbon dioxide microbubbles into the hepatic artery selected for transcatheter arterial chemoembolization. RESULTS: In angiographically undetectable hepatocellular carcinomas, sonographic angiography revealed tumor vascularity in 17 patients in whom transcatheter arterial chemoembolization was then performed. For the two patients who underwent a second transcatheter arterial chemoembolization, the existence of alternative feeding vessels was confirmed by sonographic angiography. In the remaining 10 patients, tumor vascularity was not seen on sonographic angiography; percutaneous ethanol injection therapy was then performed. Sonographic angiography clearly revealed tumor vascularity in patients in whom staining became obscure on digital subtraction angiography after the catheter was inserted into a peripheral branch of the hepatic artery. In all 24 patients who underwent transcatheter arterial chemoembolization, sonographic angiography was useful for determining the artery suitable for transcatheter arterial chemoembolization and for monitoring tumor perfusion in the selected artery. CONCLUSION: Sonographic angiography can be used to determine not only the therapeutic strategy for treatment of hepatocellular carcinoma but also whether the tumor is supplied by the artery selected for transcatheter arterial chemoembolization, especially when the tumor is not revealed by digital subtraction angiography.

Aged↗
PubMed1997

[Acute disseminated encephalomyelitis].

Acute disseminated encephalomyelitis (ADEM) occurs late in the course of viral infection, mainly exanthematous diseases such as measles, chicken pox, and rubella. Postinfectious encephalomyelitis is characterized by immune-mediated demyelination, which is found in experimental autoimmune encephalomyelitis (EAE), and virus cannot be isolated from the central nervous system. The investigations using animal models infected with. Theiler's virus or measles virus would be very useful for clarifying the mechanisms of demyelination induced by viral infection. Although the incidence of postvaccinal encephalomyelitis has fallen markedly due to development of vaccines, the neurological complications following immunization are still reported. The vaccines prepared from viruses other than live-attenuated viruses and whole-killed organisms have never been proved to induce ADEM.

Animals↗
PubMed1997

[Aortic valve insufficiency caused by nonpenetrating chest trauma difficult to distinguish from infective endocarditis with transesophageal echocardiography: a case report].

A 58-year-old man was involved in an automobile accident and suffered remittent fever, leukocytosis and high C-reactive protein level. He developed a diastolic murmur 2 months after the accident. Transesophageal echocardiography showed severe aortic regurgitation with a vegetation-like echo image attached to the right coronary cusp leaflet, suggesting infective endocarditis. Intensive medical treatment for 11 months did not improve the vegetation-like echo-image, so aortic valve replacement was performed. Disruption of the right coronary cusp leaflet was confirmed surgically. Prolapse had occurred as a result of disruption during diastole. The vegetation-like echo-image was considered to be the tip of this leaflet.

Aortic Valve Insufficiency↗
PubMed1997

[Laparoscopic retrieval of a dislocated ventriculoperitoneal shunt catheter: report of three cases and a review of the literature].

Described are 3 cases of a disconnected ventriculoperitoneal shunting system that was successfully retrieved by using a laparoscopic procedure, with a review of the literature. All patients had symptoms of increased intracranial pressure. Roentgenograms showed disconnection of a ventriculoperitoneal shunt catheter at the connecting device and its migration into the peritoneal cavity. A laparoscope was introduced into the peritoneal cavity using the double puncture procedure and the catheter was extracted in less than 15 minutes. The use of a laparoscope enabled exploration of the entire space of the cavity without any large laparotomy incision. Furthermore, the laparoscopic procedure also easily enabled introduction of a replaceable ventriculoperitoneal shunt catheter into the appropriate portion in the cavity and confirmed the CSF flow into the cavity. Because catheters which have migrated into the cavity might cause an acute abdomen, it is important that they should be removed as soon as possible. It should be kept in mind, during the procedures of extracting catheters, that the inner absorptive surface of the peritoneal cavity must be preserved as much as possible. In this regard, laparoscopic retrieval of disconnected shunt catheters is a promising method.

Adult↗
PubMed1997

Magnetic resonance imaging of hepatocellular carcinoma in Long-Evans cinnamon rats under a magnetic field of 7.05 T.

Magnetic resonance (MR) images of livers in 3-, 12- and 29-month-old Long-Evans Cinnamon(LEC) rats (male) were taken under a magnetic field of 7.05 T. MR images of sagittal and transversal sections were obtained in 1-mm-thick slices by T1-weighted and two-dimensional Fourier transformation techniques. The data matrix size was 256 phase-encoded steps. Each image was obtained through four acquisitions. Three-month-old rats gave MR images with low signal intensity over the liver probably due to the shorting of its T1 and T2 relaxation times. However, 12-month-old rats gave hyperintense regions around hepatic veins in right hepatic lobe, which was assigned to hepatocellular carcinoma. In 29-month-old rats, MR images with hyperintensity throughout the hepatic lobe were observed. These MR images, therefore, suggested that hepatocellular carcinoma in LEC rats developed from the restricted regions surrounding hepatic veins. In the present study, T1-weighted MR imaging under a magnetic field of 7.05 T was shown to be applicable to the diagnosis of hepatic cancer in LEC rats.

Animals↗
PubMed1996

p53 gene mutations in oral carcinomas from India.

In this study, we analyzed 53 oral squamous-cell carcinomas among Indians for the presence of alterations in the tumor-suppressor gene p53 by PCR-SSCP and sequencing methods. Our results showed that 21% (11/53) of oral carcinomas analyzed carried mutations within the exons 5-8 of the p53 gene. We have identified 11 single-base pair substitutions consisting of 10 mis-sense mutations and one at the splice acceptor site, and one deletion mutation involving 4 consecutive bases. The majority of the base substitutions were transitions (5 TA to CG and 5 GC to AT), while only one transversion (TA to GC) was observed. Probable hot-spots for the mutation induction were identified at codons 149 and 274, which have not been observed before in head-and-neck cancers. The mutational spectrum might have originated from base alkylations at guanine and thymine residues, caused by some alkylating agents. The present results are thus consistent with the involvement of tobacco-related nitrosoamines in the etiology of oral squamous-cell carcinoma.

Base Sequence↗
PubMed1996

Anthropometric variables and muscle properties of Japanese female ballet dancers.

Physiological characteristics of japanese female classical ballet dancers were investigated in comparison with sedentary women of similar age (non-dancers). Subjects were 20 professional female ballet dancers with a mean age of 26.5 +/- 4.4 years (mean +/- SD) and 66 sedentary women with a mean age of 23.7 +/- 3.6 years. Dancers had been trained in ballet classes for 20.4 +/- 2.4 years and had no experience of regular exercises except dance training. Body mass and % body fat measured by under-water weighing method were significantly smaller in the dancers than in the non-dancers. For all extremities, percentage of the muscle in total cross-sectional area calculated by ultra sound apparatus was significantly larger and percentage of the adipose tissue in total cross-sectional area was significantly smaller in the dancers. The maximal isometric and isokinetic force of knee flexors and the maximal isometric force of dorsi flexors (MVC force) were significantly larger in the dancers when the values were divided by body mass of each subject. During 50 repetitions of maximal plantar flexion, the isometric force of the dancers was significantly larger in all repetitions except first and second reps, though no significant difference was observed in MVC force during plantar flexion. It was suggested that the significant differences between the dancers and the non-dancers in some physiological variables might be attributed to the characteristics of dance movements/training.

Adult↗
PubMed1996

Rescue of the hairless phenotype in nude mice by transgenic insertion of the wild-type Hfh11 genomic locus.

Mice and rats homozygous for mutations at the nude (nu) locus exhibit the pleiotropic phenotypes of hairlessness and athymia. A recent positional cloning study identified, as a nude gene, a novel fork head transcription factor, Hfh11 (also called whn), that is expressed in skin and thymus, and is mutated in nude rodents. To obtain the direct biological proof that this gene is responsible for nude phenotype, we microinjected a cosmid clone containing the wild-type Hfh11 genomic locus into fertilized nude eggs. Two independent founder lines of transgenic mice were generated that corrected the hairless phenotype, but not the thymic defect. This partial rescue demonstrates that Hfh11 is the gene responsible for the hairless defect in the nude mouse. Taken together with previous genetic studies, this complementation result indicates that Hfh11 is indeed the nude gene and the Hfh11 locus is likely to be subject to complicated regulation.

Animals↗
PubMed1996

Numerical simulation of a turning alpine ski during recreational skiing.

While downhill snow skiing, recreational alpine skiers enjoy making turning motions with their skis. These motions are mainly induced by skidding, while turning by alpine ski racers is made by carving a trace in the snow. In the present study we treat the turning motions by recreational alpine skiers. This "skidding" turning motion is made possible by centripetal forces acting on the ski and skier dynamic motion systems, with these forces arising due to the skier placing the ski's longitudinal axis at an angle that is inclined away from the velocity vector and edging the ski into the snow. When snow is soft, the edged ski creates a snow impacting force, whereas a snow cutting force occurs when it is hard. Here, we calculate the former force using a three-dimensional water jet analogy, while the latter one using conventional metal cutting theory, after which the corresponding equations of motion for each system are derived and numerically solved. This methodology enables simulating the curvilinear and rotational motion of the ski and skier systems. Resultant simulations quantitatively show for the first time that the resultant radius of curvature of a ski track while downhill skiing is strongly dependent on the location of the ski boot on the ski's longitudinal axis and also on its side-cut (midlength taper).

Biophysical Phenomena↗
PubMed1996

Functions of cardiac ion channels under normal and pathological conditions.

Using the patch clamp technique, normal and abnormal functions of cardiac ion channels were studied. The transient outward K+ current contributes to the early repolarization phase of the action potential as well as to the plateau height and total duration. The latter role is observed in at premature excitations due to slow recovery from inactivation of this current compared to that of the Ca2+ current. Early and delayed afterdepolarizations are produced by multiple components of ionic currents, especially in the former case. Transient inward current is mainly involved in the formation of delayed afterdepolarizations, but the activities can be produced by a different ionic mechanism in rare occasions. Barium-induced automaticity can be brought about by blocking and unblocking of the inward rectifier K+ channels. The ATP-sensitive K+ channels are assumed to play important roles in myocardial ischemia and related conditions. The channels are a target of the K+ channel openers and their functions are modulated by various intracellular factors. While the channel activity is strongly inhibited by intracellular ATP, ATP is necessary for the channel in an operative state. The former effect by ATP is produced by its ligand action, but the latter may be brought about by hydrolysis of MgATP, which may be regulated by the assembly and disassembly of the actin cytoskeleton.

Action Potentials↗
PubMed1996

Effects of antiarrhythmic agents and Mg2+ on aconitine-induced arrhythmias.

The effects of antiarrhythmic agents, including Classes I and IV and 3-10 mM Mg2+ on aconitine-induced arrhythmias were examined using a conventional microelectrode and patch clamp method in Langendorff-perfused rabbit hearts and isolated guinea-pig ventricular myocytes. Intracoronary application of 0.1 microM aconitine induced polymorphic ventricular tachycardia (PVT) which continued for more than 60 minutes. Application of aconitine to ventricular myocytes caused a prolonged action potential duration (APD) and the appearance of early afterdepolarization (EAD) together with the occurrence of an inward hump of the I-V curve around -60 to -40 mV and increased outward current at positive voltages. Application of 10 microM TTX and 5 mM or higher Mg2+ restored aconitine-induced PVT to sinus rhythm in Langendorff-perfused preparations and also shortened the prolonged APD, demonstrating the abolishment of EAD by aconitine in ventricular myocytes. However, antiarrhythmic agents did not exert such effects. In conclusion, the antiarrhythmic actions of Mg2+ and TTX in aconitine-induced arrhythmia are to abolish EAD and shorten the prolonged APD by suppression of the inward Na+ current around -60 to -40 mV.

Aconitine↗
PubMed1996

[MRI abnormalities of the brain in neurologic complications following treatment of cancer in children].

During a 3-year period, 6 of 50 children with systemic malignacies developed neurologic complications such as hemiparesis, convulsions and loss of consciousness. The children consisted of 1 boy and 5 girls, from 3 to 12 years old, 3 with acute lymphoblastic leukemia and 3 with malignant lymphoma. Four patients received induction treatment that included intravenous administration of L-asparaginase and/or intrathecal administration of methotrexate. One patient received induction treatment and consolidation treatment that included intravenous administration of L-asparaginase. One patient received induction and consolidation treatment, and the protocol for peripheral blood stem cell transplantation. Laboratory examinations revealed coagulation dysfunction in 3 patients treated with L-asparaginase and 1 patient with disseminated intravascular coagulation (DIC). Magnetic resonance imaging (MRI) was performed on a 1.5-T unit, using spin-echo or fast spin-echo sequences. T1-weighted, T2-weighted, and proton density-weighted images were obtained in the axial and/or coronal plane (section thickness, 4 mm; inter-section gap, 2 mm). MRI was initially performed within 36 hours after the onset in all patients, and follow-up MRIs were performed for 6 months. MRI showed lesions involving the cortex and subcortex in 4 patients with coagulation dysfunction. In 2 of these 4 patients, Gd-enhanced T1-weighted images showed contrast enhancement in the surface of the gyrus, suggesting focal vascular stasis. Serial MRI revealed nearly complete resolution of the lesions. Symptoms were relieved in every case. The lesions on MRI were presumed to be due to venous thrombosis related to the coagulation dysfunction caused by L-asparaginase or DIC. On the other hand, in 2 patients with onset after intrathecal administration of high-dose methotrexate and cytarabine, MRI revealed multiple lesions involving the centrum semiovale and periventricular white matter. No Gd-enhancement of the lesion was detected. This MRI finding was consistent with leukoencephalopathy. As time passed, the symptoms improved completely, and the lesions became better demarcated. MRI is useful for differentiating lesions related to coagulation dysfunction from leukoencephalopathy.

Adolescent↗
PubMed1996

[Electrophysiology of cardiac ion channels].

Ion channels are small pores in cell membranes. They open in response to changes in membrane potentials or stimulation by bio-active substances. They selectively pass specific ions to produce electrical signals. In the heart, there are many types of channels working in concert. Diversity of action potentials within the heart comes from different distribution of ion channels in different tissues. Na channels convey inward current to initiate action potentials. Inward current through Ca channels produces the plateau and contributes to automatic activities in some situations, including membrane depolarization. Many types of K channels are now identified in cardiac tissues, including those activated only under pathophysiological conditions. K channels contribute to membrane repolarization and the maintenance of resting potentials.

Action Potentials↗
PubMed1996

[Hyperventilation and cold pressor stress echocardiography for diagnosis of vasospastic angina : report of five cases].

Two-dimensional echocardiography was used for diagnosing coronary vasospasm during the cold pressor stress test immediately after hyperventilation in five patients with suspected vasospastic angina. The test consisted of hyperventilation for 6 min and cold water pressor for 2 min under continuous electrocardiographic and echocardiographic monitoring. Coronary angiography with intracoronary injection of acetylcholine was performed in all patients within 1 month after the stress test. During the stress test, new asynergies of both the anterior and inferior walls were seen in three of the five patients, and new asynergy of the anterior wall in the other two patients. All acetylcholine induced coronary artery spasms occurred at the same locations as the new asynergies provoked by the stress test. In three patients, wall motion abnormality occurred earlier than ST segment elevation, and the other two patients had no ST changes. Chest pain was induced in three patients and delayed in comparison to electrocardiographic and echocardiographic changes. Echocardiographic monitoring during the stress test could detect spasms unaccompanied by either ST segment changes or chest pain, and could detect multivessel coronary spasms. Hyperventilation and cold pressor stress echocardiography may be used for the diagnosis of vasospastic angina.

Acetylcholine↗
PubMed1996

Modulation by dihydropyridines and protein kinases of the recombinant cardiac L-type Ca channel with multiple unitary current amplitudes.

The cloned cardiac L-type Ca channel current expressed in baby hamster kidney (BHK) cells was characterized at the single channel level. After transfection of cDNA of the cardiac alpha 1 subunit along with skeletal beta, alpha 2/delta and gamma subunits to this cell line, recombinant Ca channels could be observed at high density over extended times. The properties of cloned Ca channels were almost identical with those of native cardiac L-type Ca channels, with respect to voltage dependence of activation, unitary conductance (25 pS with 100mM Ba2+ as the charge carrier and the modulation by a dihydropyridine (DHP) Ca channel agonist and an antagonist, or by 8Br-cAMP and phorbol esters. As in native cardiac Ca channels, changes in kinetic behavior during 8Br-cAMP application included increased number of channel openings and increased duration of open times. Phorbol esters also increased the number of openings with long duration. In 27 out of 37 patches in the presence of BayK8644, small amplitude openings of several levels were observed. These openings behaved similarly to the predominant 25 pS openings during DHP and 8Br-cAMP application, with infrequent transitions to and from the predominant level. We conclude that BHK cells provide a useful expression system where the modulations and biophysical aspects of Ca channels can be studied at the single channel level.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

[A case of renal transplantation from an ABO-incompatible donor successfully pretreated with double filtration plasmapheresis].

A 40-year-old female, whose blood type was A, Rh+, was admitted to our hospital for kidney transplantation from her younger brother whose blood type was B, Rh+. Before the transplantation, we performed 4 sessions of double filtration plasmapheresis (DFPP) to remove the anti-B antibodies. The serum anti-B antibody titer lowered from X32 to X4. The kidney transplantation was carried out following the splenectomy. The warm ischemic time was 8 minutes and the cold ischemic time was 47 minutes. Five immuno-suppressive agents including cyclospolin, azathioprine, prednisolone, anti-lymphocyte globulin (ALG), and deoxyspergualin were administered in the initial period. Nine days after the transplantation, an acute rejection occurred, and 15 sessions of hemodialysis were needed. However, Methylprednisolone and OKT3 treatment resulted in recovery of the graft function. Seventy-four days after the transplantation, she was discharged with the serum creatinine concentration of 1.3 mg/dl. The DFPP before transplantation was useful to remove the anti-RBC antibody from the patient receiving an ABO incompatible kidney allograft.

ABO Blood-Group System↗