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Biomedical subjects

H Miyata

Publications and source records attributed to H Miyata.

At least 343 records · Page 19Linked to original sources
PubMed1989

Inactivation of laboratory animal RNA-viruses by physicochemical treatment.

Eight commonly used chemical disinfectants and physical treatments (UV irradiation and heating) were applied to both enveloped RNA viruses (Sendai virus, canine distemper virus) and unenveloped RNA viruses (Theiler's murine encephalomyelitis virus, reo virus type 3) to inactivate infectious virus particles. According to the results, alcohols (70% ethanol, 50% isopropanol), formaldehyde (2% formalin), halogen compounds (52ppm iodophor, 100ppm sodium hypochlorite), quaternary ammonium chloride (0.05% benzalkonium chloride) and 1% saponated cresol showed virucidal effects giving more than 99.95% reduction in the infectivity of virus samples of Sendai virus and canine distemper after 10 minutes exposure. There was no significant difference in the effects on the two enveloped RNA viruses. The susceptibility of unenveloped RNA viruses to chemical disinfectants and physical treatments differed greatly from the enveloped viruses. The two unenveloped viruses showed distinct resistance to 50% isopropanol, 2% formalin, 1% saponated cresol and to physical treatments (heating at 45, 56, 60 degrees C, and UV irradiation). These results indicate that using physicochemical methods to inactivate RNA viruses in laboratory animal facilities should be considered in accordance with the characteristics of the target virus. For practical purposes in disinfecting enveloped RNA viruses, 70% ethanol, 0.05% quaternary ammonium chloride and 1% saponated cresol diluted in hot water (greater than 60 degrees C) are considered as effective as UV irradiation. For unenveloped RNA viruses, halogen compounds, more than 1,000 ppm sodium hypochlorite or 260 ppm iodophor are recommended over a period of 10 minutes for disinfecting particles, although these compounds result in an oxidation problem with many metals.

Animals↗
PubMed1989

Evaluation and clinical applications of measurement of urinary growth hormone in diabetic subjects.

Quantities of growth hormone (GH) excreted into the urine over 24 h were measured by the highly sensitive sandwich enzyme immunoassay in 63 non-insulin-dependent diabetes mellitus (NIDDM) subjects, 6 insulin-dependent diabetes mellitus (IDDM) subjects, and 17 age-matched nondiabetic control subjects. GH-provocative tests with intravenous infusion of arginine revealed that urinary GH levels are closely correlated with the integrated concentrations of serum GH (r = .931, n = 14, P less than .001). Furthermore, 24-h urinary GH in control and diabetic subjects was inversely related to body mass index (r = .359, n = 80, P less than .001). The mean 24-h urinary GH in NIDDM subjects was 11.1 +/- 1.9 ng/g creatinine (Cr), which was not significantly different from that in nondiabetic control subjects (9.2 +/- 2.7 ng/g Cr). By contrast, the individual values for IDDM subjects varied widely, and their mean values (42.5 +/- 20.8 ng/g Cr) were much greater than those in the control and NIDDM subjects (P less than .01). The degree of glycemic control does not seem to affect 24-h urinary GH in NIDDM. The mean 24-h urinary GH in 7 subjects with proliferative diabetic retinopathy was comparable to that in subjects without retinopathy or with background retinopathy. Thus, the measurement of 24-h urinary GH appears to provide reliable assessments of endogenous GH secretion under physiological conditions and will be a useful tool for obtaining further insight into the role of GH in diabetes.

Adult↗
PubMed1989

Gait disturbances in patients with labyrinthine and cerebellar diseases.

In order to clarify the peculiarities of gait disturbances appearing in patients with labyrinthine and cerebellar disturbances, the upward-downward (U-D), right-left (R-L) and forward-backward (F-B) movements of the head and activities of both soleus muscles were recorded by a polygraph and a data recorder with the aid of a five-channel telemeter. The power spectrum and correlation analyses were carried out with a PDP-11 computer. The following are results obtained from walking with the eyes closed. (1) On normal subjects, the power spectrum of U-D head movement indicated a rise at about 2 Hz. The autocorrelograms of U-D, R-L head movements and soleus muscle activities showed a chopping or sine wave process with an attenuation of amplitude. A cross correlogram revealed that when the head was inclined to the right side, the contralateral soleus muscle was active and when the head was inclined forward, one of the soleus muscles was active. (2) A patient with bilateral loss of labyrinthine function showed an increased R-L head sway and irregularly undulating F-B head movement, indicating disturbances of the labyrinthine righting and linear movement reflexes. (3) A patient with cerebellar atrophy indicated irregular U-D, R-L and F-B head movements. The soleus muscle activity changed irregularly.

Cerebellar Diseases↗
PubMed1989

Analysis of standing posture in patients with bilateral loss of labyrinthine excitability.

The forward-backward and right-left sways in the upright standing posture were examined using stabilometry and analysis with a 5-dimensional feedback model. The forward-backward sway was found to have a fast, hidden periodicity, composed of sways due to a loss of the labyrinthine righting reflex upon the head and interaction between the head and knee sways. Furthermore, on the basis of our previous investigation, the forward-backward sway was found to depend on the increased spinal reflexes caused by a loss of labyrinthine inhibitory control upon the antigravity muscles. The right-left sway is slow and irregular, being mainly produced by disturbance of the head righting reflex.

Feedback↗
PubMed1989

[Osseointegrated implants in clinical dentistry. Follow up maintenance phase].

The aim of this study is to determine the method of maintenance care for support the functional condition during long period. The present paper reports on the result of osseointegrated titanium fixture in four complete denture patients. The marginal soft tissue reactions were investigated at the 1st, 3rd, 6th, 12th and 18th month after prothetic restrations by clinical examination and microbiological observations. All abutments were surrounded by clinically in healthy gingiva, however most individuals with the implant fixture had used as a complete denture for many years, without oral hygiene. For a favorable prognosis of the implant-recipients, self plaque control should be acquired for the patients shortly after prothetic restration. Before the healing phase, it is necessary to recall frequently for maintenance marginal soft tissue and prothetic restoration. After healing and remodeling phase, the interval of maintenance care was decided on each 3rd months. The interval seemed practically reasonable because the 18th month later the prognosis was satisfactory. This report presents two cases of complications during the maintenance phase of osseointegrated implants. Case I: A 72-year-old female patient presented gingival hyperplasia formation around the abutment after 19th months on abutment setting. We performed excision of the hyperplastic gingiva and apically positioned flap. Probing depth (PD) could not be determined because of gingival hyperplasia formation before operation, but there was marking reduction of probing depth after operation. The gingival bleeding index (GBI) was improved and the amount of gingival crevicular fluid (GCF) was reduced after operation. In pre-operative anaerobic culture, the proportions of Capnocytophaga species and Haemophilus actinomycetemcomitans were found. Post-operatively, Capnocytophaga sp. was not found, but H. actinomycetemcomitans was unchanged. Case II: A 47-year-old male patient presented gingivitis around the abutment after 13th months on abutment setting. We performed cleaning of the abutment surface with the flap procedure. Furthermore, a joint screw between the fixture and abutment was adapted due to loosening after operation, PD was unchanged, GBI was improved and GCF was slightly reduced. In pre-operative anaerobic culture, Bacteroides intermedius was rich. Post-operatively, B. intermedius was not found. In conclusion, we advocate that maintenance care of osseointegrated implants is the most important factor in the procedure.

Aged↗
PubMed1989

[Responses of premotor neurons for the trigeminal motor nucleus to stimulation of the cortical masticatory area and natural stimulation of the oral-facial area].

The premotor neurons for the trigeminal motor nucleus were recorded in the supratrigeminal region and parvocellular reticular formation. The responsiveness of these neurons were tested to electrical stimulation of the cortical masticatory area and to natural stimulation applied to the oral-facial area. Fourteen neurons were recorded in the supratrigeminal region and 16 neurons in the reticular formation. A greater number of neurons activated by stimulation of the cortical masticatory area was found in the reticular formation than in the supratrigeminal region. The latency of cortically induced responses of supratrigeminal neurons was longer than that of the neurons of reticular formation. Tactile stimulation of oral-facial area activated 14% of 14 supratrigeminal neurons, which would be including inhibitory relay neurons for the masticatory motoneurons. This result indicate that the many neurons with other functions would be existed in the supratrigeminal region.

Electric Stimulation↗
PubMed1989

[Evaluation of toxic effects on yusho causal substances by chick embryo hepatic microsomal enzymes activities].

PCBs, non-ortho chlorine substituted PCBs (Co-PCBs), PCQs and (PCDFs + PCDDs), all of which contained similar compositions of those corresponding in yusho oil, were prepared from a PCB preparation used as a heat exchanger fluid. After dissolved in 1, 4-dioxane, they were applied into the air sac of white leghorn eggs incubated for 16.5 days at 37.5 degrees C. Forty eight hours after injection, the hepatic benzo(a)pyrene hydroxylase (AHH) and 7-ethoxyresorufin deethylase (EROD) activities were assayed. The average relative potencies of induction for the two microsomal drug metabolizing enzymes by (PCDFs + PCDDs), Co-PCBs, PCBs and PCQs were 100, 13.4, 0.0006 and 0.0004, respectively. The toxic effects for yusho disease by these substances were calculated from the relative enzyme induction potencies and the average concentrations in yusho oils with the production dates of February 9 and 10, 1968. Consequently, the relative toxicities of (PCDFs+PCDDs), Co-PCBs, PCBs and PCQs were 100, 13.2, 0.06 and 0.12, respectively. This result, as well as our previous investigations using rats and monkeys, insists that (PCDFs+PCDDs) are the primary causal agents for yusho disease. However, the Co-PCBs, which were recently detected in the yusho oils by us, were revealed to be fairly effective in yusho manifestation. In addition, it was cleared that the hepatic enzyme induction by the Co-PCBs fraction, which contained other several PCB isomers, was almost completely contributed by only Co-PCBs such as 3,4,3',4'-tetra- 3,4,5,3',4'-penta- and 3,4,5,3',4',5'-hexachlorinated biphenyls present in the fraction. A chemical uptake rate from the air sac by the chick embryo decreased significantly in the cases of extremely high doses of PCBs (10,000 micrograms/egg) and PCQs (3,333 and 10,000 micrograms/egg), and result the elevations of hepatic enzymes activities were depressed, indicating that the suitable chemical dose amount to be less than about 1,000 micrograms/egg.

Animals↗
PubMed1989

[Application of a nonisotopic southern hybridization method for sex determination from bloodstains found in criminal spots].

Bloodstains collected from criminal spots were submitted to the nonisotopic Southern hybridization (NISH) method for sex identification (Kobayashi et al., J. Forens. Sci., 33, 613-620, 1988). A RNA probe, transcripted from a Y-chromosome specific DNA sequence (Nakahori et al., Nucl. Aci. Res., 14, 7569-7580), was used for this series of investigations. Among the 95 bloodstain specimens studied, in which the sex of each was previously known, 54 (88.5%) of 61 male stains were appropriately determined to be male by the NISH method, and 28 (82.4%) of 34 female bloodstain specimens were estimated to be female. The sex of the 13 remaining stain specimens were unable to be determined by this method, but no specimen was erroneously misidentified. With regard to 12 specimens, in which the sex of each was unknown at the time of the NISH test, 5 were determined as being male and 3 were estimated as being female, though the sex of the remaining 4 specimens could not be determined. The causes in the stains that made determination impossible were analyzed using patterns of ethidium bromide fluorescence of electrophoresed gel and/or NISH, and it was concluded that this could be due to an insufficient quantity of extracted DNA (12 cases), the resistance against a restriction enzyme (EcoRI) (3 cases), and the depolymerization of the Y-chromosome specific fragment (2 cases).

Blood Stains↗
PubMed1988

Fibre conduction velocity and fibre composition in human vastus lateralis.

The relationship between muscle fibre composition and fibre conduction velocity was investigated in 19 male track athletes, 12 sprinters and 7 distance runners, aged 20-24 years, using needle biopsy samples from vastus lateralis. Cross sectional areas of the fast twitch (FT) and slow twitch (ST) fibres were determined by histochemical analysis. The percentage of FT fibre areas ranged from 22.6 to 93.6%. Sprinters had a higher percentage of FT fibres than distance runners. Muscle fibre conduction velocity was measured with a surface electrode array placed along the muscle fibres, and calculated from the time delay between 2 myoelectric signals recorded during a maximal voluntary contraction. The conduction velocity ranged from 4.13 to 5.20 m.s-1. A linear correlation between conduction velocity and the relative area of FT fibres was statistically significant (r = 0.84, p less than 0.01). This correlation indicates that muscle fibre composition can be estimated from muscle fibre conduction velocity measured noninvasively with surface electrodes.

Adult↗
PubMed1988

Cerebro-cerebellar projections from the lateral suprasylvian visual area in the cat.

1. A projection from the medial bank of the lateral suprasylvian visual area, one of the targets of the cerebello-cerebral projection, back to the cerebellar cortex was demonstrated electrophysiologically in the cat. The anatomical pathways underlying this projection were investigated using orthograde and retrograde transport of wheatgerm-agglutinin-conjugated horseradish peroxidase (WGA-HRP). 2. Responses were recorded in the cerebellar cortex on stimulation of the medial bank of the lateral suprasylvian area, and were compared with those evoked by stimulation of the motor cortex and the crown part of the parietal association cortex. 3. Responses induced by stimulation of the lateral suprasylvian area were shown to consist of early mossy and late climbing fibre responses. The mossy fibre response was evoked, at a latency of 2-3 ms, predominantly in the lateral part of the contralateral cerebellar cortex (mainly, crus I, crus II, dorsal paraflocculus and paramedian lobule) and the posterior part of the vermis (mainly, lobules VII and VIII). Climbing fibre responses were elicited with the preceding mossy fibre responses and were elicited at a much longer latency than the motor cortex-induced climbing fibre response. 4. The orthograde and retrograde HRP studies suggested that the mossy fibre response is mediated by the pontine grey whereas the climbing fibre response is conveyed indirectly to the inferior olive which sends the climbing fibres to the cerebellar cortex. After WGA-HRP injections into both the medial bank of the lateral suprasylvian area and the cerebellar responsive area, orthogradely labelled terminals of cortico-pontine projection fibres and retrogradely labelled ponto-cerebellar neurones were found in the pontine grey, where distributions of the two kinds of labelling overlapped. On the other hand, retrograde neuronal labelling alone was found in the inferior olive, implying that the climbing fibre responses evoked from the lateral suprasylvian area were relayed via indirect cortico-olivary pathways.

Action Potentials↗
PubMed1988

Pseudo-exponential growth in length of the fission yeast, Schizosaccharomyces pombe.

The growth patterns of individual cells of the fission yeast (Schizosaccharomyces pombe wild-type cells, strain 972 h-; cells exposed to hydroxyurea; and cdc mutants, 11-123, 2-33) were investigated by time-lapse photomicrography. Wild-type cells showed one, two, or three linear-growth segments followed by a constant-length stage. Cells with two segments were most frequent. Hydroxyurea cells that divided as oversized cells (about three times the birth length) had three linear-growth segments in a cycle. Mutant cdc11-123 cells did not divide but had a constant-length stage separating the cycles; both the first and second cycles consisted of two linear-growth segments, and cells were oversized at the second constant-length stage (about 3.5 times the birth length). Elongating cdc2-33 cells that did not divide and were oversized (about five times the birth length) while under observation, showed four linear-growth segments. Cells of all strains showed 30 to 40% increase in growth rate at the rate-change point and maintained approximate exponential (pseudo-exponential) growth. We conclude that the normal growth pattern of individual fission-yeast cells is the pseudo-exponential pattern.

Hydroxyurea↗
PubMed1988

[Pharmacological studies of eicosapentaenoic acid ethylester (EPA-E) on high cholesterol diet-fed rabbits].

The effects of eicosapentaenoic acid ethylester (EPA-E) at daily doses of 3 and 30 mg/kg (p.o.) on vascular lesions and changes in blood components were investigated in rabbits fed with a 1% cholesterol diet for 12 weeks and partly compared with those given 30 mg/kg/day (p.o.) of ticlopidine. EPA-E at 30 mg/kg significantly improved the reduction in distensibility of isolated thoracic aorta caused by cholesterol diet feeding. Ticlopidine at 30 mg/kg also showed significant but milder improvement. EPA-E at 30 mg/kg, unlike ticlopidine, tended to lower cholesterol content in the thoracic wall and elastin fraction. Although EPA-E did not act on plasma total cholesterol, HDL-cholesterol and triglyceride contents, it tended to mildly reduce platelet aggregability in response to sodium arachidonate and the increased production of TXA2-like activity by platelets. In addition, daily doses of 30 mg/kg EPA-E caused a significant increase in plasma and platelet EPA-E contents without any change in docosahexaenoic acid and arachidonic acid contents. From these results, daily administration of EPA-E to cholesterol diet-fed rabbits caused a remarkable improvement of the reduction in distensibility of isolated thoracic aorta. The mechanism of this improvement by EPA-E appears to depend on the protection of elastic fibers from lipid deposition on the vascular wall.

Animals↗