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Biomedical subjects

M Sakai

Publications and source records attributed to M Sakai.

At least 793 records · Page 44Linked to original sources
PubMed1982

Effects of serum, tissue extract, conditioned medium, and culture substrata on neurite appearance from spinal cord explants of chick embryo.

The effects of serum, tissue extracts, conditioned medium, (CM), and culture substrata on neurite appearance from spinal cord explants of 6- to 8-day-old chick embryos were investigated. In Eagle's minimum essential medium (MEM) with no supplement neurites from explants did not appear on collagen coating but on polyornithine coating (PORN). It is concluded that cell-to-substratum interaction is important in neurite appearance. CM, serum and tissue extract potentiated neurite appearance, but their activities were highly dependent on the coating. The amount of collagen was also crucial. On collagen, neurite appearance was observed only when promoting substances were present. CM and serum contained at least two components; one affected neurite appearance after deposition on collagen and the other affected neurite appearance when present in the culture medium. The former was included also in tissue extracts. Both of adsorbable and non-adsorbable components from any origin were necessary for effective induction of neurite appearance. Heat treatment and dialysis differentiated these active components. On PORN, CM highly potentiated neurite appearance. The activity of the CM was reproduced by its low molecular weight fraction. Serum also promoted neurite appearance, but to a lesser extent than CM. The effect of tissue extract was not remarkable.

Animals↗
PubMed1982

Surface contraction waves in amphibian eggs.

Circular waves of change in brightness, known as 'surface contraction waves' (SCW-1 and SCW-2), propagate over the animal surface of amphibian eggs at each cycle of cleavage. Movement of carbon particles attached to the egg surface indicated that SCW-1 involves expansion of the egg surface, whereas SCW-2 accompanies surface contraction. Stiffness of the cortex as measured by applying negative pressure through a micropipette increased concomitantly with the passage of SCW-2. Measurement of stiffness at two loci on the egg surface with two sets of pipettes confirmed the spatio-temporal coincidence of the wave of stiffness and SCW-2. The stiffness showed either no change or even a slight decrease on passage of SCW-1. Thus SCW-2 is a genuine wave of 'contraction', but SCW-1 can more properly be called a 'surface relaxation wave'.

Animals↗
PubMed1982

Alphafetoprotein messenger RNA in human embryonal carcinoma grown in nude mice, and cloning of its complementary DNA.

Messenger RNA for human apha-fetoprotein (AFP) was partially purified from human testicular embryonal carcinoma grown in nude mice. DNA complementary to the mRNA was synthesized, tailed with oligo(dC) and inserted at the PstI site of the plasmid pBR322 tailed with oligo(dG). Escherichia coli strain LE392 was transformed with the chimeric plasmid and colonies were screened for human AFP mRNA sequences by hybridization with DNA complementary to mouse AFP mRNA (greater than 95% pure). Five colonies showed positive hybridization. The plasmid pHAF2, containing the largest insert, 900 nucleotides, was further characterized by hybrid-arrest of translation of AFP mRNA, restriction endonuclease mapping and partial nucleotide sequence analysis. It was found that the AFP complementary DNA (cDNA) sequence in pHAF2 corresponded to the 3'-end of AFP messenger RNA (mRNA), and showed a restriction map entirely different from that of mouse AFP cDNA clones previously reported.

Animals↗
PubMed1982

[Left ventricular hypertrophy in hypertensive and athlete's hearts: echocardiographic and vectorcardiographic characteristics].

The difference in the patterns of left ventricular hypertrophy (LVH) between the athlete's heart (Judo player: Judo-Ath group) and the hypertensive heart (HT group) was studied using vectorcardiography and echocardiography. The both groups were classified into two types based on the pattern of a QRS loop vector in the horizontal plane, respectively. One type (type II) satisfied the vectorcardiographic criteria of LVH by Upshaw, and the other (type I) did not satisfy it. The subjects composed of 12 Ath-I, 18 Ath-II, 10 HT-I and 16 HT-II. In the Ath-I, the characteristic vectorcardiogram was demonstrated in the horizontal plane, where an increased amplitude of an initial QRS vector was in the right and anterior direction. A mean ratio of the thickness of the interventricular septum to left ventricular posterior wall (IVSTd/PWTd) was 1.20 (p less than 0.001) in their echocardiograms. In HT-I, on the other hand, a decreased amplitude of an initial anterior vector and an increased amplitude of a posterior vector were observed in the horizontal plane. IVSTd and PWTd did not increase in these patients. These results indicated that an increased amplitude of an initial QRS vector in Ath-I is a reflection of the increased IVSTd. In type II, both IVSTd and PWTd were symmetrically increased. Concerning a spatial maximum QRS magnitude and left ventricular mass (LV mass), there was a significant correlation between the two only in HT-II (r = 0.75, p less than 0.01). It was concluded that there was some vectorcardiographic and echocardiographic differences between the left ventricular hypertrophic patterns of the athlete's heart and the hypertensive heart.

Adult↗
PubMed1982

Assessment of postoperative hearing in 528 middle ear and mastoid surgery cases in Tokai University Hospital.

The postoperative hearing results in cases of tympanoplasty, radical mastoidectomy, modified radical mastoidectomy and tympanoplasty combined with modified radical mastoidectomy on 528 ears, performed in the Tokai University Hospital between 1975 and 1980 were assessed. The assessment was based on pure-tone audiograms taken 3 months to 5 years after the operation. Out of 528 cases 70.5% gained better postoperative hearing, 6% showed no change of hearing and 23.5% showed deterioration of hearing. Auditory success of those who attained social hearing, air-bone gap closure to within 20dB or gained hearing of 20 dB or more was 53.4%. The results in cholesteatoma cases were poorer than those of non-cholesteatoma cases. In 44% of the cases, ossiculoplasty was performed, and the most successful ossiculoplasty results were obtained when the malleus was repositioned to the head of the stapes. Fairly good results were achieved when an artificial prosthesis, such as a Teflon-piston, Gelfoam-wire or platinum-piston, was used. The least successful results were found when the incus was transpositioned. In the non-ossiculoplasty group, type I tympanoplasty produced 59.5% auditory success whereas 37.3% auditory success was achieved in radical mastoidectomy. Better auditory success rates were obtained when the bony bridge was preserved than when it was removed. The results were identical in cases where the mastoid cavity was obliterated or when it was kept open. A new technique, "scutumplasty", was used for reconstructing the scutum. Revision surgery was required in only 3.4% of the cases.

Hearing↗
PubMed1982

[A correlative study of M-mode echocardiograms and pathological findings in mitral ring calcification].

Correlation between pathologically proved mitral ring calcification (MRC) and M-mode echocardiographic findings was examined. Subjects for this study were 36 aged autopsy cases of MRC (14 men, 22 women) with a mean age of 78.9 years. Echocardiographic diagnosis of MRC was based upon the following criteria; a dense echo that moves parallel to the endocardium of the left ventricular posterior wall, immediately posterior to the mitral leaflet and its abrupt termination during a sweep of the beam to the left atrium and left ventricle. The length along the mitral ring and its maximal cross-sectional diameter of MRC were measured pathologically. Extension of MRC to the mitral commissures was also evaluated. The following results were obtained; (1) The larger was the size of MRC measured pathologically, the more it was easily diagnosed by echocardiography. (2) The width of MRC in the echocardiogram correlated well with the pathologically measured maximal cross-sectional diameter of MRC (r = 0.67, p less than 0.01). (3) Sensitivity in the diagnosis of MRC was better in the echocardiograms (58.3%) than in the plain chest X-ray films (38.9%) (p less than 0.05). The length of MRC equal to or greater than 30 mm was diagnosed in all by the echocardiograms. In contrast, only 78.6% of these were diagnosed by plain X-ray films. (4) When cases with MRC were divided into 2 groups according to the mitral diastolic descent rate (MDDR), the decreased group (MDDR less than 35 mm) had a significantly longer length of MRC (32.4 +/- 15.5 mm) than the non-decreased group (16.6 +/- 20.9 mm) (p less than 0.05). Extension of MRC to the mitral commissures was more frequently observed in the group with decreased MDDR than in non-decreased group (p less than 0.005). From these observations, it was suggested that mechanical restriction of the movement of the anterior mitral; leaflet due to involvement of the commissures by MRC may be a contributing factor for decreased MDDR. (5) Identification of echoes from the posterior mitral leaflet and the left ventricular posterior wall was difficult in cases with positive MRC echoes.

Aged↗
PubMed1981

Evoked potential in the lateral geniculate body as modified by enucleation of one eye in the albino rat.

Evoked potential was recorded from the lateral geniculate body (LGB) in response to stimulation of the uncrossed optic nerve in rats with one eye removed at varying days of age after birth. A postsynaptic component of the evoked potential was found to be potentiated if the enucleation was made during the first 30 postnatal days. It was speculated that when enucleation was made during 10 days after birth potentiation would be brought about by an increase in the number of the uncrossed optic nerve fibers, but enucleation after that period would produce potentiation by terminal sprouting of the regular uncrossed optic nerve fibers. In addition, the possibility was discussed that enucleation in the first 30 days might also produce potentiation by a more efficient or more numerous transmitter release at the regular uncrossed optic nerve terminals.

Aging↗
PubMed1981

Reconstitution into liposomes of membrane proteins involved in ribosome binding on rough endoplasmic reticulum. Ribosome-binding capacity.

A membrane protein fraction having a high affinity for polyribosomes was isolated from microsomal membranes of rat liver and was incorporated into liposomes made from microsomal lipids to evaluate the polyribosome-binding capacity of the reconstituted liposomes, with the following results. (1) The polyribosome binding to the reconstituted liposomes depended on the amounts of polyribosomes added to the binding mixture. (2) Liposomes made from lipids alone did not bind any polyribosomes. (3) The polyribosome-binding capacity of the reconstituted liposomes was very sensitive to proteolytic enzyme and strongly inhibited by addition of 0.1 mM-aurintricarboxylic acid or by increasing KCl concentration. These results suggest that the binding mechanism of polyribosomes to the reconstituted liposomes is much like that for rough microsomal membrane stripped of endogenous polyribosomes.

Animals↗
PubMed1981

Intracellular activity and morphology of the prefrontal neurons related to visual attention task in behaving monkeys.

Neurons of the prefrontal-premotor cortex, which had been studied electorophysiologically during a modified reaction time task, were identified by intracellular pressure micro-injection of horseradish peroxidase (HRP). The cells were classified into those showing a sustained vs. transient change in activity during performance of the task. Cells showing a sustained response were found to have their somata in layers III and VI and cells showing transient responses were found to have their somata in layers II and III. All cells were pyramidal cells with spiny dendrites.

Afferent Pathways↗