Search PubMed⌕ Search

Biomedical subjects

Y Ohno

Publications and source records attributed to Y Ohno.

At least 451 records · Page 25Linked to original sources
PubMed1991

Acute and chronic stability of atrial screw-in leads.

The purpose of this study was to evaluate the acute and chronic stability of the atrial screw-in lead. In this study, we used CPI model 4165, 4166, and 4266 porous tip screw-in leads in 32 patients (12 for AAI pacing and 20 for DDD pacing). All of these leads were fixed to the free wall of the right atrium and used as the unipolar type. Acute voltage and current thresholds, lead impedance, P-wave amplitude, and chronic threshold were measured. Early and late complications were also investigated. The average acute stimulation thresholds at 0.6 msec pulse width were 0.82 +/- 0.43 V and 1.1 +/- 0.6 mA. Mean lead impedance was 627.2 +/- 83.1 ohms, and mean P wave amplitude was 3.1 +/- 1.1 mV. After an average follow-up period of 32 months (range: 2-72 months), we found the results of the chronic threshold study to be satisfactory. The thresholds were usually below 0.1 msec pulse width with the nominally programmed pacemaker output. Only one patient required a higher output due to an increased threshold. With regard to complications, neither lead dislodgment nor cardiac perforation was observed. In conclusion, acute and chronic thresholds were satisfactory and no serious complications occurred. Therefore the atrial screw-in lead has long-term reliability and stability.

Adult↗
PubMed1991

Extracellular ATP stimulates steroidogenesis in bovine adrenocortical fasciculata cells via P2 purinoceptors.

Effects of ATP and other purine derivatives on steroidogenesis in primary cultured bovine adrenocortical fasciculata cells were examined. At concentrations higher than 1 microM, ATP showed a potent stimulative effect on the cortisol production of the cells. The potency order of the steroidogenic effect of the tested purine derivatives was ATP greater than ADP much greater than adenosine much greater than AMP. alpha,beta-Methylene ATP had no stimulative effect on the steroidogenesis at concentrations as high as 1 mM. Theophylline did not antagonize the steroidogenic effect of ATP. These results suggest that bovine adrenocortical fasciculata cells possess the P2y purinoceptors that are linked to steroidogenesis.

Adenosine↗
PubMed1991

Ontogeny of absence-like and tonic seizures in the spontaneously epileptic rat.

The ontogeny of epileptic seizures in spontaneously epileptic rats (SER; zi/zi, tm/tm) was studied by examining behaviour and electroencephalogram (EEG) simultaneously. Weight gain and survival time were also studied. Compared with the control Kyo:Wistar rats, SER showed a much smaller increase in body weight. All male and female SER died before 20 and 18 weeks of age, respectively. Body tremor was observed at 2 weeks of age but disappeared after 11 weeks. Staggering gait appeared after 7 weeks of age, and intensified with age. Absence-like seizures characterized by paroxysmal appearance of 5-7 Hz spike-wave-like complexes were observed in the cortical or hippocampal EEG after 5 weeks of age, and tonic seizures with low voltage fast waves were observed after 6 weeks of age. All SER exhibited both absence-like and tonic seizures with high frequencies from 12 weeks of age. Differences with other spontaneous rat models of epilepsy and application methods for estimating seizure-inhibitory effects of anti-epileptic drugs are discussed.

Animals↗
PubMed1991

Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae. Mucociliary pathology of the eustachian tube.

Otitis media with effusion (OME) is generally benign and self-limiting but is often recurrent and can change into a chronic type. We have previously reported that intratympanic inoculation of lipopolysaccharide (LPS) from Klebsiella pneumoniae can develop experimental OME in the guinea pig. However, OME induced by 10 micrograms/ml of LPS was of a self-limiting type. Our hypothesis was that a higher concentration of LPS might develop a chronic OME because LPS reduces the ciliary activity in the tubotympanum in a dose related manner. In our present study we inoculated 100 micrograms/ml of LPS from K. pneumoniae into the tympanic cavity of the guinea pig, in the hope of illuminating a possible mechanism predisposing to the chronicity of the disease. A longer-term OME was observed after tympanic inoculation of 100 micrograms/ml of LPS. Ciliary activity in the Eustachian tube was depressed for a longer term by this dose than by the previous one. In addition to mucociliary pathologies and general inflammatory changes similar to those induced by 10 micrograms/ml of LPS, intracytoplasmic ciliary cysts were observed after inoculation of 100 micrograms/ml of LPS, which appeared to show disturbed ciliogenesis and chronic mucociliary lesions. In conclusion, intratympanic inoculation of a higher concentration of LPS developed a longer-term OME in the guinea pig, which was supported by functional as well as morphological examinations.

Animals↗
PubMed1991

Histamine-induced mucociliary dysfunction and otitis media with effusion.

Histamine, which has been found in middle ear effusions, is a potent pharmacological mediator released at an early stage of allergic reactions or general inflammatory process, increasing permeability of small blood vessels. Histamine might be involved in the origin and chronicity of middle ear effusions. In this study we studied the effect of histamine on the mucociliary function. First we examined the effect of histamine and its H1 and H2 blockers on the ciliary activity in the middle ear. 10(-2) M of histamine deteriorated ciliary activity; however, at lower concentrations ciliostimulatory effects were demonstrated for histamine (between 10(-8) M and 10(-4) M). Such ciliostimulatory effects were not affected by diphenhydramine (H1-blocker) but were reduced by cimetidine (H2-blocker). Thus histamine stimulates ciliary activity by combining with H2-receptor. Intratympanic injection of 10(-4) M of histamine induced accumulation of middle ear effusions (MEEs). The volume of MEEs was largest at 1 day postinjection when its mucociliary clearance time was longest. Then the mucociliary clearance time became shorter, but it was still significantly longer than that of the control animal. Ciliary activity in the tubotympanum showed no recovery through the observation period. On the other hand, intratympanic injection of 10(-6) M of histamine produced MEEs at 1 and 3 days postinjection when the mucociliary clearance time was longer than that of the control group. At 8 days, when most ears did not demonstrate MEEs, the mucociliary clearance time and ciliary activity in the Eustachian tube and tympanic orifice reached the level of the control group. Our present study demonstrates that histamine can induce mucociliary dysfunction of the tubotympanum resulting in middle ear effusions, and that cilia, especially those present in the tube and the tympanic orifice, have a significant role in eliminating middle ear effusions.

Animals↗
PubMed1991

Influenza A virus-induced otitis media and mucociliary dysfunction in the guinea pig.

There is much epidemiologic, clinical and laboratory evidence that viral infection is involved in otitis media with effusion (OME). However, few studies have demonstrated any direct influence of viruses on the tubotympanum. The purpose of this study was to establish the effect of influenza A virus having invaded the tubotympanum and so elucidate the possible mechanism by which this virus contributes to the pathogenesis of OME. Eighty guinea pigs with normal otoscopic findings were inoculated with 0.2 ml suspension of influenza A (3.3 x 10(8) PFU/ml) into the tympanic cavity through the tympanic membrane. To serve as controls, the same number of guinea pigs were injected with 0.2 ml of physiologic saline solution into the tympanic cavity. At 3, 7, 14, and 28 days postinoculation, they were used for examination of the mucociliary function. Middle ear effusions as well as mucociliary dysfunction were observed only in the animals inoculated with the virus. The ciliary activity in the bulla was declined at any time examined. On the other hand, the ciliary activity in the Eustachian tube and the tympanic orifice was slightly lowered between 7 and 14 days, but the level was not different from that of the controls. However, the number of active ciliated cells (showing more than 500 beats/min) was significantly smaller than that of the controls. The mucociliary clearance time of the tubotympanum was more prolonged than that of the controls at 3, 7, and 14 days, and returned to the control level at 28 days. A variety of morphological changes were observed in the tubotympanum treated with the virus. Major pathologies observed included general inflammatory cell infiltration, vacuolation and other degeneration of ciliated cells, and vascular damage and increased vascular permeability. Regeneration of cilia or ciliated cells followed the degeneration, which included an increased number of basal cells and newly formed centrioles. However, the viral infection also affected the epithelial cells with new centrioles. Our study demonstrates that viral infection can evoke mucociliary dysfunction of the tubotympanum and create increased susceptibility to bacteria. Therefore, viral infection may enhance bacterial infectious processes in the tubotympanu thereby contributing to the occurrence of OME.

Animals↗
PubMed1991

Ciliary activity in the tubotympanum during type I allergic reaction.

The immune system is active in the tubotympanum and some middle ear diseases might be partially or exclusively immunologically mediated. However, the effect of an allergic reaction on the tubotympanic cilia remains to be elucidated. The response of normal tubotympanic cilia from the guinea pig was investigated in an in vitro experimental system to evaluate ciliary responsiveness without the influence of secretions. Mucosal samples were obtained from three different tubotympanic locations (Eustachian tube, and middle ear close to the tube (proximal site) and more distal to the tube (distal site)). Each mucosal sample was cultured in 2 ml of RPMI 1640 and 1 ml of heparinized venous blood from a nonallergic human subject, a patient with ragweed-sensitive nasal allergy, or 3 patients with Dermatophagoides farinae-sensitive nasal allergy. One microgram of D. farinae extracts was added in each chamber to evoke an in vitro allergic reaction, and the ciliary activity of the most active cell in each culture was monitored for up to 120 min. When D. farinae extracts were added into the chamber containing blood from subjects without sensitivity to D. farinae, no changes were induced in ciliary activity throughout the examination. When the same dose of allergens was added into the chamber containing blood from D. farinae-sensitive subjects, ciliary excitation was induced in the culture from the Eustachian tube and the proximal site. The peak and plateau of this phenomenon were observed at 30-40 min after the addition of the allergen, and a gradual slowdown to the baseline level was observed after the plateau. No ciliary depression was induced by an allergic reaction in the culture from the Eustachian tube or the proximal site. Such ciliostimulatory effects were correlated with D. farinae induced-percent histamine release from whole blood. In the cultures from the distal site, however, a gradual ciliodepression followed the peak of ciliary excitation. In conclusion, an in vitro allergic reaction affected the ciliary activity in the distal site, but such ciliary dysfunction was not observed in the Eustachian tube or the proximal site during such a reaction.

Animals↗
PubMed1991

[Influenza A virus-induced mucociliary dysfunction of tubotympanum].

There is amount of epidemiologic, clinical and laboratory evidence to document that viral infection is involved in otitis media with effusion (OME). However, few studies have demonstrated the direct influence of viruses on the tubotympanum. The purpose of this study is to establish the effect of influenza A virus invaded in the tubotympanum, in an attempt to elucidate the possible mechanism by which the virus contributes to the pathogenesis of OME. 80 guinea pigs with normal otoscopic findings were inoculated with 0.2ml suspension of influenza A (3.3 x 10(8)PFU/ml) into their tympanic cavities through their tympanic membranes. To serve as controls, the same number of guinea pigs were injected with 0.2ml of physiologic saline solution into their tympanic cavities. At 3, 7, 14, and 28 days postinoculation, they were used for examination of the mucociliary function. Middle ear effusions were observed only in the animals inoculated with the virus. Mucociliary dysfunction was observed only in the animals inoculated with the virus. The ciliary activity in the bulla was declined at any time examined. On the other hand, the ciliary activity in the eustachian tube and the tympanic orifice was slightly lowered between 7 and 14 days, but the level was not different from that of the control. However, the number of active ciliated cells (showing more than 500 beats/min) was significantly smaller than that of the control. The mucociliary clearance time of the tubotympanum was more prolonged than that of the control at 3, 7, and 14 days, and returned to the control level at 28 days. A variety of morphologic changes were observed in the tubotympanum treated with the virus. Major pathologies observed included a general inflammatory cell infiltration, vacuolation and other degeneration of ciliated cells, and vascular damage and increased vascular permeability. Regeneration of cilia or ciliated cells followed the degeneration, which included an increased number of basal cells and new formed centrioles. However, the viral infection had an influence on the epithelial cells with new centrioles. Our study has demonstrated that viral infection could evoke mucociliary dysfunction of the tubotympanum and create an increased susceptibility to bacteria. Therefore, viral infection could enhance bacterial infectious process in the tubotympanum. Through the failure viruses could contribute to the occurrence of OME.

Animals↗
PubMed1991

[Studies on the uptake of 8-anilino-1-naphthalene sulfonate by rat freshly isolated renal cells].

The addition of 8-anilino-1-naphthalene sulfonate (ANS) into rat renal cell suspension caused a rapid increase in fluorescence (Ex. 400 nm, Em. 470 nm). The increase in fluorescence seemed to be composed of two phases. When the cells were disrupted by ultrasonic wave, the fast phase (0-ca 20 sec) increased and the slow phase (after ca 40 sec) disappeared. The rate of increase in the slow phase was dependent on the concentration of ANS and on the ambient temperature. A double reciprocal plot of the rate and the concentration exhibited straight line. It was decreased by bromophenol blue and rose bengal but not by other organic anions like p-aminohippuric acid and several metabolic inhibitors. It seemed that the uptake of ANS into the renal cell is mediated by a carrier which is different from that for p-aminohippuric acid.

Anilino Naphthalenesulfonates↗
PubMed1991

[A method of interval estimation for number of patients in the nationwide epidemiological survey on intractable diseases].

A method for estimating the intervals for the number of patients with intractable diseases from nationwide epidemiological surveys was developed under the assumption that response is independent of frequency of patients. This method is based on data utilizing the number of response hospitals classified by their reported number of patients. The approximate 95% confidence intervals of numbers of several intractable diseases patients were estimated using this method.

Data Interpretation, Statistical↗
PubMed1991

The lactic acid and citric acid content in the gingival fluid of orthodontic patients.

Alveolar bone turnover has two phases: bone resorption and formation. Bone resorption entails both mineral removal and collagenolysis. A pH decrease over the local bone surface is required for mineral removal. Both lactic acid and citric acid has been suggested as the acids which remove crystals. During the orthodontic movement of teeth, a process of overall bone resorption occurs during displacement, whereas at the retention stage this process needs to be stopped in order to stabilize the alveolar bone. Thus, lactic acid and citric acid may be valid parameters of bone resorption intensity. The purpose of this investigation is firstly to test if these acids can be detected in gingival fluid around the moving teeth, and secondly to find if any changes occur before, during and after orthodontic tooth movement. The results indicate that these acids can be good parameters which show how favorably tooth movement is proceeding. They also show how stable the teeth are when orthodontic force is stopped to apply.

Adolescent↗
PubMed1991

[Significance of umbilical plasma concentrations of catecholamines and their metabolites in patients with term vaginal deliveries].

In an attempt to further clarify the physiological significance of Catecholamine (CA) s in the feto-placental unit, umbilical plasma concentrations of CAs and CA metabolites, 3-methoxy-4-hydroxy-phenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in cases of full-term vaginal deliveries by HPLC-ECD. Results were as follows. 1. Norepinephrine (NE) and epinephrine (E) levels were significantly higher in arterial than in venous plasma, but no significant arterio-venous differences were found with dopamine (DA) concentrations. 2. High concentrations of MHPG, DOPAC and HVA were demonstrated in both arterial and venous plasma. 3. DOPAC and HVA levels were significantly higher in arterial than in venous plasma, but no significant arterio-venous differences were noted with MHPG. 4. A significant positive linear relations hip was demonstrated between arterial levels of NE and MHPG as well as DA and DOPAC, DA and HVA. 5. Arterial plasma MHPG levels were correlated significantly with arterial plasma pH and pO2. These results suggest that, in the feto-placental unit, NE, E and DA turnover is increased at term vaginal deliveries, and NE and E secretion sensitively responds to fetal respiratory and metabolic states. In addition, it is suggested that the mechanism which controls the DA turnover is different from that of NE and E.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Antenatal diagnosis of twin-twin transfusion syndrome by Doppler ultrasound.

We evaluated 31 pairs of twins: six with twin-twin transfusion syndrome, four discordant, and 21 concordant twins. The criterion for the retrospective diagnosis of discordancy was a difference in birth weight of 20% of the larger infant's weight. Using pulsed Doppler evaluation of the umbilical artery of each twin, the pulsatility index (PI) was used to evaluate the umbilical arterial waveforms. The differences in the PI from the twin-twin transfusion syndrome cases between 24-31 weeks significantly exceeded those of the cases without this syndrome (P less than .05). Seven cases had inter-twin differences in PI above 0.5, six of which had the twin-twin transfusion syndrome. The difference in PI seemed to predict the risk of twin-twin transfusion syndrome: The difference was high before the appearance of hydrops fetalis in those with this syndrome, whereas the difference in PI from discordant twin cases, except for those with the syndrome, was low.

Female↗
PubMed1991

[A case of facioscapulohumeral muscular dystrophy complicated with complete A-V block].

Myocardial involvement and serious electrocardiographic abnormalities are rare in patients with facioscapulohumeral (FSH) muscular dystrophy. We reported a case of FSH muscular dystrophy complicated with complete A-V block. The case was that of a 48 year-old male with the complaints of exertional dyspnea. His chest X-ray showed cardiomegaly, and the electrocardiogram recorded on admission showed complete A-V block. On the His bundle electrogram, complete A-H block and prolongation of H-V intervals were noted. Therefore, a permanent pacemaker was implanted, and he has been doing well for over 10 years after implantation. Although it is well known that serious electrocardiographic abnormalities are not infrequently associated with Duchenne's progressive muscular dystrophy (DMD), there are few reports about pacing therapy for patients with muscular dystrophy. Because the daily activity of patients with rapidly progressive type of muscular dystrophy such as DMD is at a very low level, they do not require pacing therapy. Whereas in patients with the FSH type of muscular dystrophy, which is a slowly progressive type, their daily activity is maintained at a high level. Therefore, pacing therapy should be recommended if the FSH type of muscular dystrophy is accompanied with serious bradyarrhythmias.

Facial Muscles↗
PubMed1990

Plasma von Willebrand factor and thrombomodulin as markers of vascular disorders in patients undergoing regular hemodialysis therapy.

Increased plasma levels of von Willebrand factor antigen (vWF:Ag) are regarded as reflecting the release reaction by vascular endothelial cells and/or endothelial cell injury, and increased levels of thrombomodulin (TM) antigen as reflecting damage to endothelial cells. We investigated changes in plasma vWF:Ag and TM antigen levels during the course of regular hemodialysis treatment (RDT) in 14 patients undergoing RDT in order to evaluate the effect of hemodialysis (HD) on endothelial cells. vWF:Ag and TM were both measured by the sandwich EIA method. Predialysis levels of vWF:Ag and TM in RDT patients were both significantly higher than normal control values. Neither patient age nor blood pressure was not correlated with predialysis vWF:Ag and TM levels. Both vWF:Ag and TM levels significantly increased during a single HD session. There was a positive correlation between predialysis TM levels and duration of HD and an inverse correlation between the amount of vWF:Ag released during HD and duration of HD. It appears that HD procedures induce stimulation and damage of endothelial cells and that long-term, recurrent HD treatment may predispose to vascular disorders.

Adult↗
PubMed1990

A case-control study of prostatic cancer in Kyoto, Japan: sexual risk factors.

A case-control study on prostatic cancer was conducted in Kyoto, Japan, from 1981-1984, including 100 patients with prostatic cancer (PC) and age, hospital, and date-of-admission matched controls of benign prostatic hyperplasia (BPH) patients and general hospital patients. Analysis of several sexual factors obtained through a self-administered questionnaire revealed the following observations: 1) cancer patients had fewer sex partners before marriage (relative risk, RR = 0.35; 95% confidence interval: 0.13-0.93) than the hospital controls; 2) they had more vigorous sexual activities in the third (RR = 2.89; 1.01-8.28) and fourth decades of life (RR = 2.26: 1.03-4.95) than hospital controls, but no significantly different sexual activities from controls in other decades; 3) they had less frequent orgasms (RR = 2.55; 1.11-5.83) than BPH controls or (RR = 4.96: 1.78-13.9) hospital controls, and sexual intercourse appeared to be less satisfactory (RR = 2.08: 1.05-4.13) than that of hospital controls; and 4) they had less frequent episodes of sexually transmitted diseases (RR = 0.36: 0.16-0.83) than BPH controls. Marital status, fertility, ejaculation, masturbation, nocturnal emission, contraceptive use, and wife's episodes of sexually transmitted disease were not linked to prostatic cancer risk.

Case-Control Studies↗
PubMed1990

Aleukemic leukemia cutis.

A 39-year-old man had multiple nodules on the skin. The appearance of atypical monocytes in a skin biopsy specimen preceded the onset of overt acute monocytic leukemia by 14 months.

Adolescent↗