PubMed Health⌕ Search

Biomedical subjects

M Akai

Publications and source records attributed to M Akai.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Effects of atherogenic risk factors on asymptomatic brain infarct].

This study was done to clarify the relationship between asymptomatic brain infarcts and risk factors for atherogenis. A total of 312 patients (151 men and 161 women) who had no neurologic deficits were enrolled. Their ages ranged from 41 to 83 years (mean age 63 years). The patients were divided into two groups: 158 patients without asymptomatic brain infarct and 154 patients with at least one asymptomatic brain infarct of at least 5 mm as diagnosed by magnetic resonance imaging. The patients with asymptomatic brain infarct were more likely than those without asymptomatic brain infarct to be 65 years old or older, and to have essential hypertension, diabetes mellitus, or atrial fibrillation. Among patients with hypertension the frequency of left ventricular hypertrophy or hypertensive ocular findings (Scheie's class H2) was significantly higher in those with asymptomatic brain infarct than in those without asymptomatic brain infarct. These results indicate that aging, essential hypertension (especially with left ventricular hypertrophy or hypertensive ocular findings), diabetes mellitus, and atrial fibrillation are associated with asymptomatic brain infarct.

Adult↗
PubMed1996

Clinical experiences with a convertible thermoplastic knee-ankle-foot orthosis for post-stroke hemiplegic patients.

As rehabilitation for post-stroke hemiplegic patients has become widely accepted practice, there has been an increase in patients who are more difficult to treat. In the prescription rationale of orthoses for hemiplegics, the knee-ankle-foot orthosis (KAFO) for the lower limb has generally been underestimated because of its inhibitory effect on the normal walking pattern and also its interference with gait training. The authors had an experience of 28 hemiplegics with severe physical impairments who were fitted with a convertible plastic KAFO. Among these patients, there were 11 cases in which the KAFO was replaced by an ankle-foot orthosis (AFO) within 1.5 to 8 months (average 4 months) following initial prescription when they were able to control their knee actively. Ambulatory capability in these patients was superior to that of the remaining KAFO group. The Barthel index of the AFO group patients was higher than the KAFO group (p < 0.01). However neither age, sex, severity of hemiplegia, starting time of rehabilitation following onset of stroke, time of fitting with the orthosis, nor the functional recovery stage were critical factors between the two groups, only the incidence of major complications affected ambulatory capability.

Adult↗
PubMed1996

[Immunodeficiency with thymoma (Good's syndrome) similar to sino-bronchial syndrome].

A 58-year-old man was admitted to our hospital because of recurrent pulmonary infections that began three years previously. Laboratory data showed hypogammaglobulinemia and a chest computed tomogram showed diffuse bilateral micronodular shadows and an anterior mediastinal tumor. Immunodeficiency with thymoma (Good's syndrome) was diagnosed. After undergoing a thymectomy, he received intravenous gamma-globulin injections once a month for prophylaxis. Good's syndrome occurs rarely in Japan. A solid tumor-like shadow is not necessarily observed in routine chest X-ray studies, and hypogammaglobulinemia is one sign of this syndrome. The hypogammaglobulinemia of Good's syndrome should be carefully differentiated from that of other immunodeficiency diseases such as common variable immunodeficiency, the acquired immunodeficiency syndrome, chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and multiple myeloma (non-secretory type).

Agammaglobulinemia↗
PubMed1995

[Lung injury and pulmonary vascular endothelial cell injury].

Pulmonary vascular endothelial cells are an important barrier that helps keep lung tissue intact. These cells are exposed to potentially injurious cells and to harmful mediators that are produced in or released into the blood. The endothelial cells may then be stimulated and injured. Stimulated and injured pulmonary vascular endothelial cells can themselves produce and release injury-promoting mediators. Using isolated perfused rat lungs and cultured human pulmonary endothelial cells, we assessed the effect of neutrophil-derived injurious mediators, leukotoxin, and neutrophil elastase on the pulmonary endothelium. Both mediators caused high-permeability pulmonary edema in the isolated lungs and caused dose-dependent and time-dependent damage in the cell cultures. Injury due to leukotoxin was suppressed in the presence of LNMMA or superoxide dismutase and injury due to neutrophil elastase was suppressed by neutrophil elastase inhibitors. These data indicate that these mediators cause lung injury via different mechanisms and that they may synergistically evoke clinical lung injury.

Acute Disease↗
PubMed1993

Effect of direct current stimulation on triradiate physeal cartilage. In vivo study in young rabbits.

Electrical stimulation with 8 microA direct current was applied to the triradiate physeal cartilage of young rabbits for periods of 3, 4, and 5 weeks. The effect was evaluated by morphometric measurement and histological observation. We tried to improve some previously described technical problems (e.g., movement of electrode during experiment) in this model of the growing acetabulum. Statistically significant differences in acetabular depth were found between the experimental and the control side in the 3-week group, but no obvious differences were found among the other measurements. Characteristic thickening of the growing physeal cartilage, especially proliferating cells, was found in the stimulated sides. Electricity affects the cell behavior in the triradiate physeal cartilage as well as the growth plate of long bone, but further study is still necessary to find more appropriate conditions to gain actual growth.

Acetabulum↗
PubMed1993

Viscoelastic properties of stiff joints: a new approach in analyzing joint contracture.

The purpose of this study was to analyze the joint stiffness after immobilization in a rat's lower extremity model. Rat knee joints were surgically immobilized in a full flexed position for periods of up to 7 weeks with or without intra-articular intervention. The biomechanical analysis was assessed by measuring the bone-joint-bone sample as a cantilever. Measurement was performed with (a) knee flexion angle with gravity, (b) fast Fourier transform analysis of time-dependent mechanical noise with random frequencies, and (c) dynamic stiffness and loss tangent with sinusoidal vibration at a certain frequency. The results showed that the conventional static mechanical test could not detect the intraarticular changes of the whole knee joint. The measurement of the viscoelastic properties covering wide frequencies revealed that an accurate change occurred.

Animals↗
PubMed1992

Changes of cytochemical properties in the Golgi apparatus during in vivo differentiation of the ameloblast in developing rat molar tooth germs.

The cytochemical changes of the Golgi stacks occurring concomitantly with cell differentiation were examined in ameloblasts of developing rat molar tooth germs using osmium impregnation and cytochemistry with nicotinamide adenine dinucleotide phosphatase (NADPase), thiamine pyrophosphatase (TPPase), and acid phosphatase (Acpase). NADPase, TPPase, and Acpase activities were already present in the Golgi stacks of the inner enamel epithelial cells, the undifferentiated form of the ameloblast: NADPase activity existed in the medial Golgi cisternae, TPPase activity in the trans Golgi cisternae, and Acpase activity in almost all cisternae and strongly in the trans-most cisterna of the Golgi stack. At this stage, however, osmium deposits after impregnation were not observed in the cisterna of Golgi stacks but were present in some small vesicles. These vesicles were located throughout the cytoplasm. Osmiophilic cisternae in the Golgi stacks were apparent for the first time at the stage when the Golgi apparatus developed and migrated to the region distal to the nucleus with the progression of cell differentiation. These findings indicate that the cis subcompartment of the Golgi apparatus was incomplete in the inner enamel epithelial cells with regard to appearance of its cytochemical property, as compared with the medial and trans subcompartments. It is suggested that the cis compartment of the Golgi stack may be completed only in the last stage of the compartmentalized Golgi organization during differentiation of the ameloblast.

Acid Phosphatase↗
PubMed1992

Distribution of calcitonin gene-related peptide and substance P-immunoreactive nerve fibers and their correlation in the periodontal ligament of the mouse incisor.

The distribution of calcitonin gene-related peptide (CGRP)- and substance P (SP)-immunoreactive (IR) nerve fibers and their correlation in the periodontal ligament of mouse incisors were examined by indirect immunofluorescence. Both CGRP-IR and SP-IR thin nerve fibers were abundant in the apical and middle third of the periodontal ligament. In the lingual portion of the incisal periodontal ligament, these nerve fibers were localized in the alveolar half of the periodontal ligament and were observed as free nerve endings. No CGRP-IR and SP-IR specialized nerve endings, such as Ruffini-like corpuscles, were observed. In the labial periodontal ligament, CGRP-IR and SP-IR nerve fibers ran along the incisal axis. The distribution of CGRP-IR nerve fibers was very similar to that of SP-IR nerve fibers.

Animals↗
PubMed1991

Case report 685: Ossifying fibromyxoid tumor of the soft parts of the upper arm.

We report an unusual case of an ossifying tumor arising in the deep soft tissue adjacent to the humerus of a 72-year-old woman. The tumor exhibited sarcoma-like features histologically, although its clinical course unexpectedly differed from that of a malignant tumor. We diagnosed this particular case as an ossifying fibromyxoid tumor of soft parts, which has been recently described by Enzinger et al.. This is another example of an ossifying soft-tissue tumor which simulates a malignant sarcoma.

Aged↗
PubMed1991

Neuropeptide Y- and substance P-like immunoreactivities in the guinea pig parotid gland.

These immunoreactivities were examined by double immunofluorescence, which demonstrated that many nerve fibres around the glandular acini and blood vessels contain neuropeptide Y and substance P. It appears that these substances may coexist in nerve fibres around acini, but that there may be two populations of fibres containing these peptides around the blood vessels.

Animals↗
PubMed1991

Ontogeny of cholinergic ganglionic cells which take up L-3,4-dihydroxyphenylalanine and contain vasoactive intestinal polypeptide in the mouse tongue.

During the prenatal development of the mouse tongue, the intralingual ganglion was investigated histochemically and immunohistochemically for acetylcholinesterase (AChE) activity, the capacity to take up L-3,4-dihydroxyphenylalanine (L-DOPA) and vasoactive intestinal polypeptide (VIP)-like immunoreactivity. AChE-positive cells were first observed at gestational day 12, and AChE-positive neurons which take up L-DOPA were found at gestational day 14, while VIP-like immunoreactive neurons were not seen until gestational day 16. The present results suggested that the cholinergic neurons within the mouse tongue can take up L-DOPA from gestational day 14 and synthesize VIP from gestational day 16.

Acetylcholinesterase↗
PubMed1991

[Effect of a direct electric current on modification of bone and ligament repair processes--experimental investigation of a rabbit model].

Investigations of the effect of direct current on 1) fracture healing, and 2) ligament healing was conducted by applying 10 microA to 1) the defect of the fibula, and 2) that of the patellar ligament of adult rabbits. After time periods for stimulation all specimens were tested with combinations of roentgenological, histological, biomechanical and biochemical methods. The results were analyzed and compared with the non-stimulated, opposite side and with the normal tissue. The electricity produced 1) a more massive callus with normal histological features in an early stages at the fracture site, and 2) higher tensile stiffness and earlier change of the collagen types in the newly-formed tissue, though no significant differences were observed as to 1) the mechanical parameters of callus and bone material, and 2) histological findings of repairing tissue. Electrical stimulation was indicated not only on bone tissue but also on non-osseous tissues and their components.

Animals↗
PubMed1990

Aversive taste stimuli increase CGRP levels in the gustatory insular cortex of the rat.

Calcitonin gene-related peptide-like immunoreactivity (CGRP-IR) was surveyed immunohistochemically in the insular cortex of the rat, and the levels of insular cortical CGRP-IR were measured with the radioimmunoassay method following intraoral stimulation with various taste stimuli. CGRP-IR was localized in nerve fibers within the agranular and dysgranular insular cortices. The CGRP-IR levels in the rostral (gustatory) part of the insular cortex were increased significantly by strongly aversive taste stimuli such as quinine hydrochloride and conditioned taste stimuli (NaCl and sucrose) which animals had been taught to avoid. The results suggest that CGRP in the gustatory insular cortex is concerned with rejection or avoidance behaviors to aversive taste stimuli.

Animals↗
PubMed1990

Re-innervation of rat molar tooth pulp following transection of the inferior alveolar nerve.

The inferior alveolar nerves (IAN) of young male Wistar rats (b.wt. greater than or equal to 200 g) were transected unilaterally, slightly proximal to the mandibular foramen under anesthesia with chloral hydrate (0.4 g/kg, i.p.). After various postoperative periods of time, the animals received horseradish peroxidase (HRP) applications to 3 mandibular molar tooth pulps on both sides and were fixed by transvascular perfusion 24 h later. Horizontal 60 microns sections of the trigeminal ganglion were incubated with tetramethylbenzidine hydrochloride and the cross-sectional areas of all the labeled neuronal cell bodies were measured. The average number of labeled cells on the untransected (control) side was 148 (n = 26), with cross-sectional areas ranging between 131.9 and 2129.6 microns 2. Of these, 42.5% fell between 300 and 600 microns 2. About 13.5% (n = 7) of the primary neurons innervating the tooth pulps escaped the ipsilateral neurotomy and were labeled by HRP application on postoperative day 0. With HRP application on postoperative day 3, the number of labeled neurons recovered to 56.8% (n = 7) that of the control and maintained this level up to postoperative day 75. From postoperative days 3 through 75, the cell size spectrum of labeled neurons on the transection side was similar to that of the control and no consistent tendency of alteration was observed; i.e. they were distributed between 134.4 and 2214.3 microns 2, with the mode being 41.5% in the range between 300 and 600 microns 2 (n = 19).

Animals↗