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Biomedical subjects

H Harayama

Publications and source records attributed to H Harayama.

33 records · Page 2Linked to original sources
PubMed1992

Influence of season on characteristics of epididymal and ejaculated semen in Meishan boars.

Most of the epididymal spermatozoa collected in all the seasons examined maintained an ability to move progressively, had a cytoplasmic droplet in the distal site of the middle piece, and were morphologically normal. Reduced desire to mount a dummy was not observed during the experimental period. Characteristics of ejaculated semen were not significantly altered throughout the year. However, progressive motility and acrosomal integrity of spermatozoa ejaculated between July and September were more susceptible to storage at 4 degrees C than spermatozoa ejaculated during the other months and acrosomal integrity of spermatozoa ejaculated during the 3 months was to freezing-thawing. These results indicate that the reproductive activity of Meishan boars in Japan is only slightly influenced by season, but semen ejaculated during the summer is less suitable for storage than that ejaculated during the other seasons of the year.

Journal Article↗
PubMed1991

Testicular development in Chinese Meishan boars.

The developmental process of the testis and age-related changes in the morphology of rete testicular spermatozoa were investigated in Meishan boars at 1 to 364 days of age. Testicular weight and the diameter of seminiferous tubules increased rapidly until 150 to 180 days of age. Leptotene stage spermatocytes, round spermatids and spermatozoa were first found in the section of seminiferous tubules at 30 to 45, 60 and 75 days of age, respectively. However, after 105 to 120 days of age, most rete testicular spermatozoa were morphologically normal. These results indicate that Meishan boars reach puberty as early as 75 days of age, though the testes acquire the ability to produce morphologically normal spermatozoa at about 120 days.

Journal Article↗
PubMed1991

A new method to measure the distribution of motor conduction velocity in man.

A new method of measuring the distribution of conduction velocities in human motor fibers is described. In this method, a modification of Kimura's collision technique is combined with Hopf's technique. This enabled us to determine the collision end-point in Hopf's technique, from which the minimum velocity is derived. The size of the distorted compound muscle action potential (CMAP) measured with Hopf's technique is corrected using the CMAP size with the modified Kimura technique. This resolves the problem of CMAP distortion due to transient change in muscle conduction in Hopf's technique. In addition, a new equation to correct for the refractory period was developed. This can be applied even if there is stimulus spread. Using our method, one can clearly determine the maximum and minimum velocities. The former corresponds to the motor conduction velocity as measured by the conventional method.

Action Potentials↗
PubMed1990

Identification of hypoxanthine and inosine in brain dialyzable fraction as stimulators for growth of porcine aortic endothelial cells in response to fibroblast growth factor in either dialyzed serum media or low serum media.

The rate of proliferation of porcine aortic endothelial cells (PAEC) in response to fibroblast growth factor (FGF) was largely retarded when incubated in Dulbecco's modified Eagle's medium (DMEM) supplemented with either 1% fetal bovine serum (FBS) or 10% dialyzed FBS in place of 10% FBS. Proliferation of endothelial cells in low serum media in response to FGF was enhanced to the level of media containing FGF plus 10% FBS by the addition of the dialyzable fraction from bovine brain homogenates. From the bovine brain dialyzable fraction, two active components were purified and identified as hypoxanthine and inosine. Either hypoxanthine or inosine, at a dose of 5 microM in DMEM with 1% FBS, maximally increased the incorporation of [3H]thymidine into DNA of PAEC in low serum media in the presence of FGF. However, no additive effect was observed when hypoxanthine and inosine were added simultaneously. The present data indicate that the proliferative action of FGF on PAEC can be potentiated by hypoxanthine and inosine.

Animals↗
PubMed1990

[Auditory brainstem response and somatosensory evoked potential in Machado-Joseph disease in Japanese families].

To clarify physiological aspects of Machado-Joseph disease (MJD), we studied auditory brainstem response (ABR) and somatosensory evoked potential (SEP) in 17 clinically diagnosed patients with MJD aged 32-64 in Japanese families. ABR was recorded in 13 patients. In 8 patients, ABR were abnormal. In 5 patients, the latency of I wave was normal, but other waves could not be evoked. In the other 3 patients, I-III interpeak latency was prolonged. SEP was recorded in 15 patients. In SEP of median nerve, 11 patients had abnormal findings, and SEP of posterior tibial nerve revealed abnormal findings in all 15 patients. In all patients, responses from Erb's point and popliteal fossa were normal in latency, but other peaks were low in amplitude or absent, and the latency and central conduction time (CCT) were prolonged. The result of ABR indicated the involvement of the brainstem auditory pathways in MJD, and the result of SEP suggested that somatosensory pathways, particularly central pathways, would be involved in the disease process. ABR and SEP can be potential diagnostic methods for detection of subclinical abnormality in MJD patients.

Adult↗
PubMed1989

Fibroblast growth factor-stimulated growth of porcine aortic endothelial cells depends on hypoxanthine in fetal bovine serum in culture media.

The rate of proliferation of porcine aortic endothelial cells (PAEC) in response to stimulation of fibroblast growth factors (FGFs) was largely retarded in media supplemented with 10% dialyzed fetal bovine serum (FBS) in place of nondialyzed FBS. This inhibition was overcome by supplement of dialyzable fraction, and hypoxanthine was purified from the dialyzable fraction as the active compound which stimulated the basal and FGF-dependent growth rates of dialyzed FBS-treated PAEC. Addition of hypoxanthine (5 microM) to media with 10% dialyzed FBS containing FGFs (10 ng/ml) markedly increased the rate of both cell proliferation and DNA synthesis of PAEC, and their maximal levels were comparable to those attained by cells in media with 10% nondialyzed FBS. Hypoxanthine changed the spindle-like morphology of dialyzed FBS-treated PAEC even in the presence of FGFs into the cobblestone-like morphology of regular PAEC in media with 10% FBS.

Animals↗
PubMed1986

Joseph's disease: clinical and pathological studies in a Japanese family.

Joseph's disease is a hereditary ataxia found among descendants of Portuguese from the Azores Islands. We describe the clinical and pathological features of 4 members of a Japanese family who were diagnosed as having Joseph's disease. The illness began with cerebellar ataxia between the ages of 18 and 45 years. Nystagmus, dysarthria, and pyramidal signs were early manifestations. External ophthalmoplegia, dystonia and/or athetotic movements, and muscular atrophy appeared in the late stages. Neuropathological findings in one patient revealed degeneration of the dentatorubral and pallidoluysian systems, substantia nigra, pontocerebellar system, Clarke's column and spinocerebellar tracts, and anterior horn cells, as well as the cranial nuclei in the brainstem. Neurons in the inferior olivary nuclei, Purkinje's and granule cells, the cerebral cortex, thalamus, and striatum were spared. Involvement of the dentatorubral and pallidoluysian systems seems to be a characteristic feature of this disease in Japan.

Adolescent↗
PubMed1984

Changes in reciprocal Ia inhibition during voluntary contraction in man.

Reciprocal Ia inhibition from ankle flexors to extensors was studied during voluntary tonic isometric dorsiflexion and plantar flexion in five normal subjects. The Ia inhibition was examined as the short-latency suppression of the soleus H-reflexes by stimulation of the low-threshold afferents in the common peroneal nerve (Mizuno et al. 1971). At rest, weak Ia inhibition was demonstrated in four subjects out of five, the maximal amount being 14.1 +/- 5.0% suppression of the control H-reflex. The absolute amount of inhibition, which was calculated by subtracting the mean size of the conditioned H-reflex from that of the control H-reflex and expressed as a percentage of the maximal M-response, increased during ankle dorsiflexion, and decreased or disappeared during plantar flexion in parallel with the amount of contraction. The neural mechanisms for facilitation of the Ia inhibitory pathway during dorsiflexion were considered to support the hypothesis of "alpha-gamma-linkage in reciprocal inhibition", i.e. combined facilitatory effects on the Ia inhibitory interneuron from the supraspinal centers directly and indirectly via the gamma motoneuron--Ia afferent route. The mechanism for inhibition of the pathway during plantar flexion was considered to be inhibition of the Ia interneuron of the flexor side by Ia interneuron of antagonist extensors. A quantitative aspect of activity in the reciprocal Ia inhibitory pathway on the performance of voluntary movement is revealed in this study.

Adult↗
PubMed1984

Adrenoleukodystrophy: a clinical variant presenting as olivopontocerebellar atrophy.

A case of adrenoleukodystrophy showing neurological features of olivopontocerebellar atrophy is described. A CT scan demonstrated marked atrophy in both cerebellum and pons. ACTH stimulation produced no rise in the plasma cortisol level but a significant rise in the plasma aldosterone level. The ratios of C26:0 to C22:0 in fatty acids of sphingomyelin from erythrocyte membrane and plasma were increased.

Adrenocorticotropic Hormone↗
PubMed1983

Quantitative analysis of stance in ataxic myxoedema.

Postural abnormalities in a 66-year-old woman with ataxic myxoedema were recorded by stabilography during treatment. After replacement therapy, 3 Hz power in the sagittal plane was greater than before treatment; this peak shifted to a higher frequency and finally its ratio became normal. This is the first report of recovery of a 3 Hz body oscillation in ataxic myxoedema.

Aged↗
PubMed1979

Slow cord dorsum potentials elicited by descending volleys in man.

Human cord dorsum potential (CDP) was recorded from the posterior epidural space at the levels of cervical and lumbar enlargements, using epidural catheters as the recording electrodes, in 15 normal volunteers and six patients suffering from amyotrophic lateral sclerosis. In normal subjects the CDP elicited by descending volleys consisted of spike potentials followed by sharp negative and slow positive waves which were very similar to the P1, N1, and P2 potentials, respectively, of the CDP evoked segmentally. By contrast, in all patients with amyotrophic lateral sclerosis both the sharp negative and slow positive waves were absent in the CDP elicited by descending volleys, while the pattern of each component of the segmentally evoked CDP remained unchanged. Thus, the sharp negative and slow positive waves of human CDP elicited by descending volleys might reflect the activity of interneurones and primary afferent depolarisation respectively, produced by impulses through the corticospinal tract.

Adult↗