Biomedical subjects

M Sakai

Publications and source records attributed to M Sakai.

At least 487 records · Page 27Linked to original sources

PubMed1992

Contractile response of individual cardiac myocytes to norepinephrine declines with senescence.

The present study utilized individual isolated left ventricular cardiac myocytes from hearts of animals of a broad age range to evaluate the response to norepinephrine and to other stimuli that augment myocardial cell contractile performance. During electrical stimulation before drugs neither the amplitude nor the velocity of shortening normalized for resting cell length differed among cells isolated from 2-, 6- to 8-, or 24-mo-old animals. Norepinephrine augmented twitch amplitude and velocity about fourfold in cells from 2-mo-old hearts but only by 2.5-fold in cells from 24-mo-old hearts (age effect, P less than 0.001). In contrast, the contractile response to increases in bathing [Ca2+] or to the addition of the calcium channel agonist BAY K 8644 or of 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (CPT cAMP) did not vary with age. These results indicate that the age-associated contractile deficit during beta-adrenergic stimulation is specific to the beta-adrenergic pathway and an age-associated deficit in the net production of cAMP. This can be attributed to a diminished cardiac myocyte response to beta-adrenergic agonists, in contrast to modulation of the beta-adrenergic response by other receptor agonists, which are present in intact tissue but absent under the conditions of the present study.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1992

Giant air cell of the petrous apex: a possible cause of facial hypalgesia.

A giant air cell of the left petrous apex was found in a 23-year-old man with ipsilateral facial hypalgesia. The size of the giant air cell depicted on computed tomography was 1.5 x 2.0 x 2.0 cm. A coronal T1-weighted magnetic resonance image showed that the trigeminal nerve was compressed superomedially by a large signal void area that was probably a result of excessive pneumatization of the petrous apex. It is suggested that the facial hypalgesia was caused by the compression by the giant air cell of the petrous apex on the trigeminal nerve.

Adult↗

PubMed1992

[Effect of seasonal and intermittent work at high altitude on health status].

Health status of 7 men was examined in order to study the effect of duty work cycle of 3-d stay at the altitude of 2,000 m and one-day holiday at 600 m for a period of 6 months from May to October. Their usual works were desk work and road patrol. Total hemoglobin concentration in blood increased significantly after work at high altitude, which was considered to be a compensatory response to the hypoxic state. Subjective symptoms were obtained by a self-administered questionnaire before (April), during (June and October) and after (November) work at high altitude. Fatigue was observed in three out of the seven subjects in June, which subsequently disappeared in October. Dyspnea was observed also in June in three of the subjects, which disappeared in two, persisted in one, and newly appeared in another subject in November. In contrast, a tendency of favorable effects of the work environment on nausea and lumbago was observed. Blood pressure and pulse rate were measured for 24 h. The mean systolic blood pressure during 24 h decreased in two of five subjects in October and November, and the mean values during the working hours decreased in two in October from 145 to 131 mmHg and from 147 to 129 mmHg, respectively. The blood pressure measured at health examination correlated well with the mean blood pressure during 24 h and working hours. The mean pulse rate during 24 h and working hours increased in one in June, October and November. These results indicate that adaptive responses to low barometric pressure environment developed during a work period of 5 months at high altitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Altitude↗

PubMed1992

A three-dimensional observation of acid phosphatase-positive structures in rat testis by high voltage electron microscopy.

Using a fixative of low concentrated glutaraldehyde in PIPES, we examined three-dimensional structures of acid phosphatase (ACPase) activity in the cells of testes of normal adult and 30 min heat-treated rats by high voltage electron microscopy. There were less ACPase-positive structures in germ cells, but more in Sertoli cells, particularly in residual bodies, and also in macrophages lying between seminiferous tubules. Reaction products of ACPase were distributed in the trans-most cisternae of Golgi apparatus, many spherical lysosomes, and acrosomes. The elongated thread-like lysosomes (nematolysosomes) were absent on the testicular cells. After heat-treatment of rat testis, though ACPase-positive lysosomes increased in number, nematolysosomes were never seen in Sertoli cells and most of the other testicular cells; a number of rod-like lysosomes, however, emerged in macrophages. The results indicate that (1) Sertoli cells usually have more ACPase-positive lysosomal contents than germ cells; (2) Sertoli cells are less affected by stress which may largely hurt germ cells; (3) nematolysosome is not a ubiquitous structure in all the types of cells; and (4) the function of nematolysosomes in macrophages may involve in the disposition of disintegrated cells in rat testis.

Acid Phosphatase↗

PubMed1992

[Effect of antiplatelet and anticoagulant therapy on secondary prevention and long-term prognosis after acute myocardial infarction in aged patients].

The long-term efficacy and side effects of antiplatelet and anticoagulant therapy for secondary prevention after the first acute myocardial infarction (AMI) were retrospectively assessed in 133 patients over 60 years of age during a mean follow-up period of 36.6 months. Seventy five patients received antiplatelet and anticoagulant therapy (group 1) and 58 patients did not (group 2). In group 1 patients, 54, 12 and 9 patients received ticlopidine, aspirin and warfarin, respectively. Mean age, sex ratio, site of AMI, max CPK value and left ventricular ejection fraction in the convalescent phase did not differ between the two groups. There were no differences between the two groups in terms of the number and kind of combination drugs such as nitrate, beta-blocker and Ca antagonist. During the follow-up period 40 patients died; 18 patients (45%) suffered cardiac death and 22 patients (55%) experienced non-cardiac death. Nineteen patients had recurrent MI and 37 patients had cardiac events which were defined in total as cardiac death, recurrent MI and unstable angina pectoris. The total mortality rate and rate of recurrent MI based on the life time table method were significantly lower in group 1 than in group 2 by the generalized Wilcoxon test. The cumulative total mortality rate in the fifth year was 24.2% in group 1 and 49% in group 2. The cumulative rate for recurrent MI in the fifth year was 7.4% in group 1 and 27.5% in group 2 (p less than 0.05). However, the rate of cardiac events did not differ between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

[Acute hemodynamic effects of intravenous bolus injection of isosorbide dinitrate in aged patients with congestive heart failure].

In order to investigate whether intravenous bolus injection of isosorbide dinitrate (ISDN) is a safe and efficient therapy in aged patients with congestive heart failure, we studied acute hemodynamic effects in 11 patients. Peak effects on preload were observed after 5 to 10 minutes of bolus injection and unloading effects continued effectively for 60 minutes. At peak effect, pulmonary systolic pressure decreased from 50.2 +/- 2.6 to 36.2 +/- 2.6 mmHg (-28.5%, p less than 0.01) and pulmonary end diastolic pressure decreased from 25.0 +/- 2.2 to 18.5 +/- 2.1 mmHg (-26.0%, p less than 0.01). Mean pulmonary artery wedge pressure decreased from 23.4 +/- 2.2 to 16.0 +/- 2.1 mmHg (-31.6%, p less than 0.01). Mean right atrial pressure decreased from 10.5 +/- 1.8 to 7.4 +/- 2.0 mmHg (-29.5%, p less than 0.01). Blood pressure, heart rate, cardiac index, systemic and pulmonary vascular resistance showed no significant changes. Thus, intravenous bolus injection of ISDN showed a potent vasodilator effects on preload, and may be a safe and useful treatment for aged patients with acute congestive heart failure.

Aged↗

PubMed1992

[An autopsy case of endocardial cushion defect (ECD) in an 82-year-old female].

In an 82-year-old female case of endocardial cushion defect (ECD), a systolic regurgitant murmur was heard at the apex, and her ECG showed atrial fibrillation without right bundle branch block or left axis deviation. An echocardiogram demonstrated atrial septal defect (ASD) and a cleft of the anterior mitral leaflet with calcification. She died of refractory congestive heart failure. Autopsy revealed ECD (intermediate type) with mitral and tricuspid cleft, and ASD (ostium primum type, 2.0 x 1.0 cm in diameter). In addition, mitral ring calcification and calcification of the cleft mitral valve was disclosed, causing mitral stenosis in addition to mitral regurgitation due to the cleft mitral valve. This was the second oldest Japanese autopsy case of ECD. We concluded that echocardiographic examinations, including color flow imaging, in aged patients with heart murmur are necessary to confirm the diagnosis of congenital heart disease in the aged.

Aged↗

PubMed1992

[Congestive heart failure in elderly readmitted patients].

The clinical features of congestive heart failure in the elderly were investigated in 104 patients (57 males, 47 females, mean age of 79.2). Patients were divided into two subgroups, the readmission group, 33 patients who were readmitted within 6 months after discharge, and the non-readmission group. Chief complaints were dyspnea, edema, chest pain, loss of appetite, chest compression, and palpitation. Heart failure was caused by infection, myocardial ischemia, arrhythmia, inappropriate drug usage including poor drug compliance, the use of beta-blockers, excessive intake of sodium, and anemia. Careful use of drug was essential especially in the readmission group. Major underlying heart disease were ischemic heart disease (39.4%), valvular disease (26.9%), hypertensive heart disease (9.6%), with cardiomyopathy, congenital heart disease seen in the minority. There was no statistically significant difference in underlying heart diseases between the two groups. Supraventricular arrhythmias such as atrial fibrillations, paroxysmal atrial fibrillations, paroxysmal supraventricular tachycardias, and premature atrial contractions were noted in 85.3% of the cases. Drugs for treatment were diuretics, digitalis, isosorbide dinitrate, calcium antagonists. ACE inhibitors and alpha-blockers were also used, showing that vasodilators were more extensively used than before. The major complications were hypertension (39.4%), renal dysfunction (27.9%), cerebrovascular disease (26.9%), diabetes mellitus (16.5%), arteriosclerosis obliterans (7.7%). Renal dysfunction, arteriosclerosis obliterans was seen significantly more frequently in the readmission group. The prognosis at one year after admission was significantly worse in the readmission group. In summary, the major underlying diseases were ischemic heart disease, valvular disease, and hypertensive heart disease. Ischemic heart disease was seen more frequently than in previous investigations at our hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

[Immunohistochemical study of the human olfactory system].

Taurine (2-aminoethane sulfonic acid) and carnosine (beta-alanyl-L-histidine) are found in large quantities in the olfactory epithelium and bulb. Taurine is a structurally simple amino acid, and has been reported to have several putative roles, such as neurotransmitter, neuromodulator, neurogrowth factor and to function in membrane stabilization. Carnosine, on the other hand, has been suggested as a putative neurotransmitter in the olfactory system. We have succeeded in visualizing taurine- and carnosine-like immunoreactivities (LI) in the human olfactory mucosa, and also carnosine-LI in the human olfactory bulb. For this investigation, we collected specimens of the human olfactory bulb by autopsy and from the olfactory mucosa by biopsy, and compared localization of taurine- and carnosine-LI in several cases. By means of biopsy using Nakano's forceps, samples of olfactory mucosa were obtained from 5 cases: a 17 year old female, 23 year old male, 46 year old male, 47 year old male, and a 57 year old male. The olfactory bulb of a 1 month old male was collected at autopsy. These specimens were processed for immunohistochemical study according to the peroxidase-antiperoxidase (PAP) method. In the olfactory epithelium, taurine-LI was demonstrated in some primary olfactory neurons, and in basal cells. Carnosine-LI was observed only in primary olfactory neurons, i.e., dendrites, vesicles and axonal bundles of olfactory receptor cells, but not in basal cells. In the olfactory bulb, the olfactory nerve layer and the glomerular layer showed carnosine-LI positive reactions. Therefore, taurine and carnosine may possibly coexist in some olfactory neurons. Olfactory receptor cells are classified as sensory neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Detection of Renibacterium salmoninarum antigen in migrating adult chum salmon (Oncorhynchus keta) in Japan.

Renibacterium salmoninarum antigen was detected in the kidney of migrating chum salmon (Oncorhynchus keta) using the indirect dot blot assay and indirect fluorescent antibody test. The adult chum salmon had migrated into a bay in which cultured coho salmon infected with R. salmoninarum were present. Antigen was detected in 5% of the chum salmon although they did not have clinical signs of bacterial kidney disease (BKD). This report describes the first case of R. salmoninarum antigen detection among wild chum salmon populations in eastern Asia.

Animals↗

PubMed1992

[The influence of paraquat on cell cycle--analysis of cell kinetics using DNA/BrdU staining].

We examined the in vitro and in vivo effects of paraquat on the cell cycle. After we exposed paraquat to the cultured cell (MDCK), we examined cell kinetics by flow cytometry with BrdU-PI double staining. And we administered paraquat intravenously to the rats, we collected and separated rat's liver and pulmonary cells, and we examined the cell kinetics by same method. Consequently our study found that the cells in the S-phase were noted to be abundant, and we suggested that paraquat apparently arrested the cell cycle at S time, and that DNA damage was importance in the mechanism of paraquat toxicity.

Animals↗

PubMed1992

Fibroblast growth factors released by wounded endothelial cells stimulate proliferation of synovial cells.

We demonstrated that vascular endothelial cells mechanically wounded by scraping from the substratum were able to release growth promoting factors for synovial cells as well as for endothelial cells. The wounded endothelial cell conditioned medium stimulated the proliferation of synovial cells derived from different human donors dose dependently and induced transit of growth arrested synovial cells (predominant in the G0 and G1 phases), through the S phase and into the G2 and M phases. When the wounded endothelial cell conditioned medium was applied to heparin-sepharose columns, mitogenic activity was eluted with 2.0 M NaCl. The mitogenic activity in wounded endothelial cell conditioned medium, which was heat sensitive, was inhibited by protamine sulfate and a specific mouse monoclonal antibody against basic fibroblast growth factor (bFGF). Our results are evidence that the wounded endothelial cell conditioned medium contained growth promoting factors for synovial cells, including bFGF. We also showed the presence of bFGF in the endothelial cells of the small blood vessels and stromal synovial fibroblast-like cells in patients with rheumatoid arthritis (RA). Our results suggest that the endothelial cells in the luxuriant capillaries in the synovial tissues from patients with RA may have a critical role in the stimulation of neighboring synovial cell proliferation, resulting in pronounced synovial hyperplasia.

Antibodies, Monoclonal↗

PubMed1992

Mating termination in the male cricket.

The study indicates that the male cricket Gryllus bimaculatus extrudes the spermatophore in response to mechanical stimulation of specialized sensilla in the cavity enclosed by the epiphallus and terminates mating as revealed by spermatophore protrusion. The spermatophore extrusion, however, needs an increase in body tonus during cavity hair stimulation which is produced by male's copulatory actions in response to key stimuli on the dorsum, epiproct and cerci. At the same time, male's sexual excitation raised by courtship facilitates spermatophore extrusion. This is the first demonstration that mating can be artificially switched off in male insects.

Afferent Pathways↗

PubMed1992

[New reconstruction method for defect of chest wall using composite graft].

In the case of a 64-year-old man squamous cell carcinoma in the left lung with metastasis to the rib, we excised the affected portion of the chest wall and used a composite graft, a combination hydroxyapatite (HAP) filler, for reconstruction with good results. HAP filler is a ceramic that combines the calcium phosphate apatite hydroxide with 3-calcium phosphate. The Dacron fabric used was made of polyethylene terephthalate fiber. Two layers of Dacron fabric were laid together, stitched to the rib with nylon thread, and the resulting tubular cavity packed with HAP filler to create an artificial rib. The intercostal muscle was sandwiched between the layers of Dacron fabric and the ends of the natural rib laid across those of the artificial one. We used the periosteum and intercostal muscle to integrate the graft and complete reconstruction. Postoperative recovery was good, and there was no visible sign of deformation at the graft site. Even in palpation we were unable to tell that the rib was artificial.

Biocompatible Materials↗

PubMed1992

Polyarteritis nodosa with aortic dissection: necrotizing vasculitis of the vasa vasorum.

A 59-year-old woman was admitted to our hospital with acute onset of chest pain. She had experienced high fever, weight loss, polyarthralgia, myalgia, polyneuropathy and hallucinations for 3 years before admission. The diagnosis of polyarteritis nodosa with hepatitis B surface antigenemia was made by muscle biopsy and serological examinations, and administration of prednisolone induced remission of all the manifestations. After developing the acute attack of severe chest pain, she died suddenly. At autopsy, a DeBakey type 1 aortic dissection was found and the immediate cause of death was found to be cardiac tamponade secondary to rupture of the aortic dissection. Microscopically, necrotizing inflammatory lesions were present in the medium sized vascular arteries throughout her body. Furthermore, necrotizing vasculitis was also found in the vasa vasorum of the adventitia and media of the thoracic aorta. The dissecting lesion was seen in the outer layer of the media. Our results suggest that spontaneous dissection of the aorta may be attributed to necrotizing vasculitis of the vasa vasorum.

Aortic Dissection↗

PubMed1992

[Energy metabolism, respiratory heat loss, and lung functions in patients with chronic obstructive pulmonary disease and pulmonary fibrosis].

Resting energy expenditure (REE) and respiratory heat loss (RHL) were measured in 17 patients with chronic obstructive pulmonary disease (COPD), 7 patients with pulmonary fibrosis (PF), and 8 normal healthy subjects, three hours after a light breakfast. Correlations between these values, and also predicted basal metabolic rate (PreBMR) and normalized lung functions were assessed. REE, REE/Pre BMR, RHL and RHL/REE in all patients increased significantly compared with those of control subjects. When all the studied subjects were combined, significant negative relationships were found between REE, REE/PreBMR, RHL and RHL/REE and percent predicted values of forced expiratory volume in one second (FEV1.0), between RHL and RHL/REE and percent predicted values of vital capacity (VC), and between REE/PreBMR, RHL and RHL/REE and percent predicted values of carbon monoxide diffusing capacity (DLCO). These results indicate that resting energy expenditure and respiratory heat loss increase in patients with COPD and PF in association with even slight to moderate deterioration of lung function. Therefore, elevated resting energy expenditure and respiratory heat loss need to be taken into account in determining caloric and water requirements of these patients.

Aged↗

PubMed1992

[Active infective endocarditis with idiopathic thrombocytopenic purpura: a case report].

This is a case report of infective endocarditis with idiopathic thrombocytopenic purpura (ITP). Open heart surgery to the patient with ITP has a problem of perioperative hemorrhage. Usually, treatment for ITP is performed before operation, and platelet transfusion is provided for hemorrhage. However, in our patient, we had to perform emergency operation because of progressive heart failure without treatment of ITP. Emergency operation should be performed without treatment of ITP, not to delay operative timing in such a case of progressive heart failure from active infective endocarditis.

Blood Component Transfusion↗

PubMed1992

[Clinical characteristics and prognosis of secondary amyloidosis in patients with rheumatoid arthritis--renal involvement and therapy].

Secondary amyloidosis is an important complication that may have a strong influence on the prognosis of patients with rheumatoid arthritis (RA). We studied 21 RA patients with secondary amyloidosis. The two major initial signs were gastrointestinal symptoms and renal involvement. When 15 of the 21 patients were diagnosed as having secondary amyloidosis, they displayed renal involvement including proteinuria, hematuria and hypercreatininemia. The 15 patients with amyloidosis were either subjected to dialysis or died within 35 months on the average. The causes of death in 13 patients were cardiac failure, gastrointestinal bleeding and infection, which were strongly implicated with renal failure. Dialysis was applied to seven patients. Three of them were maintained with chronic dialysis. We discussed the induction-time and the method of dialysis in patients with amyloidosis secondary to RA.

Adolescent↗