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Biomedical subjects

Y Goto

Publications and source records attributed to Y Goto.

At least 235 records · Page 13Linked to original sources
PubMed2000

Mechanoenergetics characterizing oxygen wasting effect of caffeine in canine left ventricle.

Caffeine causes a considerable O(2) waste for positive inotropism in myocardium by complex pharmacological mechanisms. However, no quantitative study has yet characterized the mechanoenergetics of caffeine, particularly its O(2) cost of contractility in the E(max)-PVA-VO(2) framework. Here, E(max) is an index of ventricular contractility, PVA is a measure of total mechanical energy generated by ventricular contraction, and VO(2) is O(2) consumption of ventricular contraction. The E(max)-PVA-VO(2) framework proved to be powerful in cardiac mechanoenergetics. We therefore studied the effects of intracoronary caffeine at concentrations lower than 1 mmol/l on left ventricular (LV) E(max) and VO(2) for excitation-contraction (E-C) coupling in the excised cross-circulated canine heart. We enhanced LV E(max) by intracoronary infusion of caffeine after beta-blockade with propranolol and compared this effect with that of calcium. We obtained the relation between LV VO(2) and PVA with E(max) as a parameter. We then calculated the VO(2) for the E-C coupling by subtracting VO(2) under KCl arrest from the PVA-independent (or zero-PVA) VO(2) and the O(2) cost of E(max) as the slope of the E-C coupling VO(2)-E(max) relation. We found that this cost was 40% greater on average for caffeine than for calcium. This result, for the first time, characterized integratively cardiac mechanoenergetics of the O(2) wasting effect of the complex inotropic mechanisms of intracoronary caffeine at concentrations lower than 1 mmol/l in a beating whole heart.

Animals↗
PubMed2000

Effects of repetitive brief ischemia on contractile efficiency and oxygen cost of contractility in dog heart.

It is unclear whether preceding repetitive brief ischemia causes any improvement in the energy efficiency of intracellular calcium cycling or crossbridge cycling that may lead to cardioprotection after subsequent sustained ischemia/reperfusion, a phenomenon called ischemic preconditioning. To address this issue, left ventricular (LV) contractility (E(max)) and the relation between myocardial oxygen consumption (VO(2)) and pressure-volume area (PVA, a measure of LV total mechanical energy) were assessed before (Control) and 20 min (Rep-20) and 60 min (Rep-60) after repetitive brief ischemia in 11 isolated, blood-perfused dog hearts. At Rep-20, E(max) and PVA-independent VO(2) (nonmechanical energy expenditure) decreased by 23.0 +/- 19.5 and 13.9 +/- 18.0%, respectively (both p < 0.05). However, at Rep-60, both E(max) and PVA-independent VO(2) recovered to their respective control levels. The oxygen cost of contractility (the slope of the PVA-independent VO(2)-E(max) relation during CaCl(2) loading) remained constant (Control 0.0019 +/- 0.0009 vs. Rep-60 0.0018 +/- 0.0013 ml O(2) x ml x mmHg(-1) x beat(-1) x 100 g(-2), ns), suggesting unchanged efficiency in Ca(2+) cycling. Also, the contractile efficiency (the reciprocal of the slope of the VO(2)-PVA relation, reflecting the efficiency of crossbridge cycling) was the same between the Control and Rep-60 (53.7 +/- 16.7 vs. 55.4 +/- 14.4%, ns). Basal metabolism VO(2) during KCl arrest was also similar to that in the normal heart. Nonmechanical energy expenditure was reduced in proportion to the decrease in LV contractility after repetitive brief ischemia, while both the contractile efficiency and oxygen cost of contractility remained constant. These results indicate that the heart, after repetitive brief ischemia but before sustained ischemia, has normal efficiencies of crossbridge cycling and Ca(2+) cycling despite the transiently reduced contractility.

Animals↗
PubMed2000

Terson syndrome caused by ventricular hemorrhage associated with moyamoya disease--case report.

A 24-year-old female presented with Terson syndrome secondary to bilateral ventricular hemorrhage as a complication of moyamoya disease. Ophthalmoscopy and magnetic resonance imaging clearly demonstrated vitreous hemorrhage in the left eye globe. Various visual symptoms are associated with moyamoya disease, almost all of which result from ischemic lesions in the visual cortex and optic pathways. In this case, the visual disturbance was caused by Terson syndrome secondary to ventricular hemorrhage. Close ophthalmological and radiological evaluation is mandatory even in patients with moyamoya disease and hemorrhagic manifestation located in the intracerebral, subarachnoid, or intraventricular space.

Adult↗
PubMed2000

Relationship between suicide and holidays.

Employing the vital statistics from January 1, 1979 to December 31, 1994 in Hokkaido Prefecture, Japan, we investigated the relationship between suicide (ICD 9 code, El15) and days of the week. In one day 1.97 males and 0.98 females committed suicide on average. On Saturdays the number of suicides per day was the smallest. On Mondays it was the highest. When the days were classified into (1) a holiday, (2) the day before a holiday, (3) the day after a holiday (4) the day both before and after a holiday and (5) others, the rate of suicide was the lowest in the days before a holiday. In the days after a holiday, however, the rate was the highest. The same tendency was also noted when the subjects were classified into several subgroups from the viewpoint of ages, seasons or calendar years. The time relation of holidays seemed to have something to do with the intention to commit suicide.

Chi-Square Distribution↗
PubMed2000

Quantification of viral ribonucleic acid in plasma of cats naturally infected with feline immunodeficiency virus.

OBJECTIVE: To assess plasma viral RNA concentration in cats naturally infected with feline immunodeficiency virus (FIV). ANIMALS: 28 FIV-infected cats. PROCEDURE: Cats were categorized into 1 of the 3 following stages on the basis of clinical signs: asymptomatic (nonclinical) carrier (AC; n = 11), acquired immunodeficiency syndrome-related complex (ARC; 9), or acquired immunodeficiency syndrome (AIDS; 8). Concentration of viral RNA in plasma (copies per ml) was determined by use of a quantitative competitive polymerase chain reaction (QC-PCR) assay. Total lymphocyte count, CD4+ cell and CD8+ cell counts, and the CD4+ cell count-to-CD8+ cell count ratio were determined by use of flow cytometry. RESULTS: Plasma viral RNA concentration was significantly higher in cats in the AIDS stage, compared with cats in AC and ARC stages. Most (5/7) cats in the AIDS stage had low total lymphocyte, CD4+ cell, and CD8+ cell counts. CONCLUSIONS AND CLINICAL RELEVANCE: Concentration of plasma viral RNA is a good indicator of disease progression in FIV-infected cats, particularly as cats progress from the ARC to the AIDS stage. Determination of CD4+ and CD8+ cell counts can be used as supportive indicators of disease progression.

Animals↗
PubMed2000

[Detection of Emericella nidulans from bedding materials in horse breeding environment and its significance as a causative agent of guttural pouch mycosis in horses].

Sixty-six new and used samples of horse bedding materials: 60 rice straws, 2 wheat straws, 2 timothy hays and 2 wood chips, were collected from horse breeding stables of 33 farms in Japan and examined for the presence of Emericella nidulans (E. nidulans; anam. Aspergillus nidulans). The incidence of E. nidulans in the bedding materials was 75.8% and there was no significant difference in detection of the fungus between the new and used materials (25 out of the 33 samples, respectively). The growth of E. nidulans isolated in sterilized rice straw culture was accelerated by the addition of water up to about Aw 0.94, which as determined to be the most favorable moisture content. The addition of 0.3% urea solution onto the sterilized rice straw culture also appeared to very effectively enhance its conidial and ascocarp formation. A significant influence of urea on conidial and ascocarp formation of E. nidulans isolates was confirmed by their cultures on a synthetic medium which had urea as the sole nitrogen. These results suggest that severe contamination of E. nidulans on new bedding materials can be hazardous and its proliferation can readily occur at the stable due to the enhancing effect of urine. This analysis is meaningful to elucidate a reservoir of E. nidulans as the causative agent of guttural pouch mycosis in horses.

Animal Husbandry↗
PubMed2000

[The use of a modified vertical mandibular osteotomy for exposure of a distal cervical internal carotid artery].

We report herein the case of a 56-year-old woman who presented with repeated transient ischemic attacks (TIAs). Cerebral angiography revealed that the left redundant internal carotid artery (ICA) uncharacteristically curved medially. These findings were highly suggestive of an internal carotid artery aneurysm at the level between the first and second cervical vertebral bodies. The lesion was presumed to be difficult to access by the surgical procedure usually adopted in carotid endarterectomy. Thus, we decided to employ a modified vertical mandibular osteotomy. The operative view revealed that the lesion was atherosclerotic stenosis with ulceration, so carotid endarterectomy was indicated. This mandibular osteotomy not only provided us with wide, satisfactory exposure of the distal cervical internal carotid artery but also afforded good mandibular stability during the postoperative period.

Carotid Artery Diseases↗
PubMed2000

[Preliminary report: first identification of known mutation in the ryanodine receptor gene in a Japanese malignant hyperthermia pedigree].

In Japan, the rate of Ca-induced Ca release (CICR) using skinned fibers of skeletal muscle has been employed as a diagnostic test for malignant hyperthermia (MH) susceptibility, since most of the typical fulminant MH patients showed an enhancement of CICR rate. Recently the Ca releasing channel responsible for the CICR was reported to be mainly the ryanodine binding Ca protein which was identified as the causative site of MH muscle according to recent genetic studies. Among patients with enhanced CICR rate, one point mutation for Arg 2434 His was recognized in a family. Although this site is related to the central core disease (CCD), this pathological change could not be observed in this patient. This is the first report describing a gene mutation in a MH family identified in Japan.

Asian People↗
PubMed2000

Endotoxin-triggered haematological interactions in Fusobacterium necrophorum infections.

The haematological mechanisms in the course of liver abscess formation were evaluated. They were examined by employing viable cells of Fusobacterium necrophorum subsp. necrophorum and Fusobacterium necrophorum subsp. funduliforme in comparison with their endotoxins. Whole cell infection with F.n. necrophorum led to neutrophilia and to a concomitant monocytosis in parallel with those responses induced by the in vivo injection of its endotoxin. Viable infection with F.n. funduliforme was characterized by a sustained endotoxin-related monocytosis against neutropenia. The stimulatory impact of endotoxin on monocytes when released from a viable F.n. funduliforme infection suggested an inherently peculiar mechanism which differed from the induction of both neutrophilia and monocytosis when F.n. funduliforme endotoxin was administered alone. The neutrophilic inducing capacity of the F.n. necrophorum endotoxin was equally illustrated by its positive chemotactic effect on polymorphonuclear neutrophils in vitro. The data presented here emphasize the virulence of F.n. necrophorum viewed in reference to changes in leucocyte trafficking and as complemented by a relatively high endotoxin content.

Animals↗
PubMed2000

[Protective efficacy of BCG Tokyo 172 in the guinea pig model of pulmonary tuberculosis].

BCG Tokyo 172 strain was examined for its protective efficacy against pulmonary tuberculosis in a guinea pig model. Guinea pigs were vaccinated with an intradermal injection of 10(3) CFU of BCG Tokyo 172 strain. BCG Copenhagen 1331 was employed as a control strain. Eight weeks after the vaccination, the animals were infected with about 10 CFU of M. tuberculosis H37Rv by a respiratory route in an aerosol chamber. Five weeks after infection, the animals were euthanized and their spleens, lungs and livers were obtained for enumeration of M. tuberculosis H37Rv and histopathological examinations. The mean log10 CFU of M. tuberculosis H37Rv recovered from right lower lung lobes of guinea pigs vaccinated with BCG Tokyo 172 (frozen), BCG Tokyo 172 (freeze-dried), BCG Copenhagen 1331 (freeze-dried) and placebo were 4.72, 4.23, 4.35 and 5.76, respectively. The mean log10 CFU of the bacteria recovered from spleens were 2.11, 1.51, 1.37 and 5.90, respectively. There was a significant difference in bacterial recovery from both lung and spleen between the vaccinated and the non-vaccinated groups. No significant difference was seen among the groups vaccinated with different strains of BCG in any organ. The lungs exhibited just small granulomatous nodules and the spleens showed no granulomatous nodules in the BCG-vaccinated guinea pigs. On the other hand, the lungs and spleens from non-vaccinated guinea pigs showed much larger granulomatous nodules with central necrosis. These histopathological difference between the vaccinated and the non-vaccinated guinea pigs was consistent with the difference of bacterial growth between them. The results of this study have clearly indicated that BCG Tokyo 172 strain possesses a significant protective efficacy against M. tuberculosis as well as BCG Copenhagen 1331 strain. These results have also shown that the respiratory infection model in guinea pigs is very useful to evaluate efficacy of vaccines against pulmonary tuberculosis.

Animals↗
PubMed2000

[Risk factors and physical activity levels at the onset of acute myocardial infarction in young men].

OBJECTIVES: The pathogenesis and triggering factors of acute myocardial infarction in young men remain unknown. To clarify the pathogenesis of acute myocardial infarction in young Japanese men, we compared the clinical features of patients with acute myocardial infarction in 2 age groups in Japan. METHODS: There were 37 male patients aged < 40 years (Young group; mean age 36 +/- 4 years, range 23-39 years) among 2,879 patients with acute myocardial infarction admitted to the coronary care unit of the National Cardiovascular Center, Japan, from 1977 through 1996. The clinical features of this group were compared with those of 110 consecutive male patients with acute myocardial infarction aged > or = 65 years (Old group; mean age 72 +/- 6 years, range 65-96 years) admitted in 1993-1994. Demographic features, physical activity levels at or within 2 hours before the onset of acute myocardial infarction, and coronary angiographic findings were analyzed. RESULTS: Compared with the Old group, the Young group had lower incidences of hypertension (p < 0.01) and diabetes mellitus (p < 0.01), a higher incidence of smoking (p < 0.01), higher levels of total cholesterol (p < 0.05) and body mass index (p < 0.05), and a lower level of high-density lipopotein (HDL)-cholesterol (p < 0.01). Also, the Young group had a higher prevalence of 0-1 vessel disease than the Old group (72% vs 35%, p < 0.01). The physical activity level was significantly higher in the Young group than in the Old group (2.6 +/- 2.2 vs 1.8 +/- 1.1 METs, p < 0.01). Furthermore, patients with multivessel disease in the Young group had a higher incidence of hypertension, a higher level of total cholesterol and a lower level of HDL-cholesterol (all p < 0.05), whereas those with 0-1 vessel disease had a higher incidence of heavy smoking (73% vs 50%, p = 0.1) and a tendency to higher physical activity level at the onset (2.7 +/- 2.2 vs 2.4 +/- 2.3, NS). CONCLUSIONS: Young male patients with acute myocardial infarction may be characterized by 2 distinctive patterns: one associated with smoking and a higher physical activity level at the onset of acute myocardial infarction with 0-1 vessel disease and the other with hypertension and hypercholesterolemia with multivessel disease.

Adult↗
PubMed2000

[Congenital nemaline myopathy with mitochondrial abnormalities. An adult case report].

We report a 42-year-old male suffering from congenital nemaline myopathy accompanied with mitochondrial abnormalities in his muscle biopsy. He had a dysmorphic face with a high-arched and narrow palate and slowly progressive generalized muscle weakness. He was still able to walk with a cane. CT showed symmetrical muscle atrophy and low densities in the thigh muscles, especially in the posterior compartment, and in the soleus muscles. Preferential posterior thigh involvement was unusual in congenital nemaline myopathy. The lumbar quadrate and paravertebral muscles were relatively well preserved; these muscles were reported to be severely involved in adult-onset nemaline myopathy patients. Muscle biopsy findings were consistent with nemaline myopathy; nemaline rods in approximately 10% of fibers, type 1 fiber atrophy, and type 2B fiber deficiency. In addition, ragged-red fibers were scattered and focal cytochrome c oxidase (CCO) deficiency was present. Formazan granules were large on succinate dehydrogenase stain. Many fibers with nemaline rods showed focal CCO deficiency. On electron microscopy, large (megaconial) mitochondria were lined regularly between Z lines. PCR and Southern blot analysis of muscle mitochondrial DNA revealed multiple deletions. It remains to be clarified whether mitochondrial abnormalities are primarily related to nemaline myopathy or secondarily induced phenomenon after a long-standing disease process.

Adult↗
PubMed2000

Conformation and stability of thiol-modified bovine beta-lactoglobulin.

Bovine beta-lactoglobulin A assumes a dimeric native conformation at neutral pH, while the conformation at pH 2 is monomeric but still native. Beta-lactoglobulin A has a free thiol at Cys121, which is buried between the beta-barrel and the C-terminal major alpha-helix. This thiol group was specifically reacted with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) in the presence of 1.0 M Gdn-HCI at pH 7.5, producing a modified beta-lactoglobulin (TNB-bIg) containing a mixed disulfide bond with 5-thio-2-nitrobenzoic acid (TNB). The conformation and stability of TNB-bIg were studied by circular dichroism (CD), tryptophan fluorescence, analytical ultracentrifugation, and one-dimensional 1H-NMR. The CD spectra of TNB-bIg indicated disordering of the native secondary structure at pH 7.5, whereas a slight increase in the alpha-helical content was observed at pH 2.0. The tryptophan fluorescence of TNB-bIg was significantly quenched compared with that of the intact protein, probably by the energy transfer to TNB. Sedimentation equilibrium analysis indicated that, at neutral pH, TNB-bIg is monomeric while the intact protein is dimeric. In contrast, at pH 2.0, both the intact beta-lactoglobulin and TNB-bIg were monomeric. The unfolding transition of TNB-bIg induced by Gdn-HCl was cooperative in both pH regions, although the degree of cooperativity was less than that of the intact protein. The 1H-NMR spectrum for TNB-bIg at pH 3.0 was native-like, whereas the spectrum at pH 7.5 was similar to that of the unfolded proteins. These results suggest that modification of the buried thiol group destabilizes the rigid hydrophobic core and the dimer interface, producing a monomeric state that is native-like at pH 2.0 but is molten globule-like at pH 7.5. Upon reducing the mixed disulfide of TNB-bIg with dithiothreitol, the intact beta-lactoglobulin was regenerated. TNB-bIg will become a useful model to analyze the conformation and stability of the intermediate of protein folding.

Animals↗
PubMed2000

[Stenting for intracranial internal carotid artery stenosis with the use of a coronary stent: a case report].

A 61-year-old man was admitted to our hospital for mild left hemiparesis and speech disturbance. An initial angiogram revealed occlusion of the right internal carotid artery (ICA) but with sufficient collateral flow by compensated the contralateral carotid artery. Severe stenosis (70%) in the intracavernous (C4-5) portion was identified in the left ICA. Cerebral blood flow was remarkably decreased in both hemispheres. The patient's hemiparesis fluctuated according to the systemic blood pressure in such a manner that induced hypertension therapy was mandatory. On the 19th hospital day, we performed stenting of the left ICA stenosis using a coronary stent. A flexible coronary stent, NIR PRIMO stent 3.0 mm/16 mm (SCIMED, Boston Scientific) was deployed after the predilatation (2.5 mm/10 atm). The initial 70% stenosis was reduced to 6% after the postdilatation (3.75 mm/8 atm). The neurological status was stable after the procedure and we stopped the induced hypertension therapy the next day. We consider that intracranial artery stenting will be a common therapeutic modality in the near future.

Carotid Artery, Internal↗
PubMed2000

[A case of polypoid form of parameatal urethral cyst].

A 45-year-old man first noticed a soft tumor on his left lip of the urethral meatus at the age of 15. The lesion had gradually been increasing in size during the last 10 years. He presented to our clinic with division of urinary stream which had been persisting for about nine months. The tumor was resected, and histopathological examination revealed that it was a mucous cyst. The cyst had an outer wall of stratified squamous epithelium and an inner wall of stratified columnar epithelium. Since the inner wall was covered with epithelium originating from the urethral mucosa and the lesion was located outside the urethral meatus, a diagnosis of parameatal urethral cyst was made. Recently, parameatal urethral cyst has rarely been reported since it is often clinically in significant and remains asymptomatic. In our patient, the tumor showed polyploid growth and caused difficulty in urination. The mechanism of its development is considered based on a review of the literature.

Cysts↗
PubMed2000

[A case of antiphospholipid antibody syndrome with cerebral infarction showing slowly progressive pure motor monoparesis in unilateral upper extremity].

We reported a 68-year-old man with anti-phospholipid antibody syndrome who presented slowly progressive pure motor monoparesis(PMM) in left upper extremity as a sign of cerebral infarction. He had history of hypertension and hyperlipidemia. He first noticed clumsiness in left fingers, then weakness of left fingers with drop hand developing gradually in 2 to 6 weeks. He began to feel difficulty in raising left upper arm in 8 weeks and was admitted to our hospital. On admission, he exhibited severe weakness in distal portion and moderate weakness in proximal portion of left upper extremity. Deep tendon reflexes were slightly hyperactive in left side. Muscle strength of right upper extremity and bilateral lower extremities were normal. There was no sensory and autonomic abnormality. Laboratory examination revealed high titer of anti-cardiolipin IgM antibody. Brain MRI demonstrated a small cortical infarction in the right precentral gyrus. Cerebral angiography revealed severe stenosis in right common carotid artery. Other examinations including EMG were unremarkable. PMM in left upper extremity was considered to be caused by the ischemic lesion in the precentral motor cortex. Slowly progressive course might be explained by the hypovolemic factor due to the marked stenosis in right common carotid artery, poor collateral circulation, and abnormal coagulation caused by anti-phospholipid antibody syndrome.

Aged↗