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Biomedical subjects

Y Yajima

Publications and source records attributed to Y Yajima.

At least 163 records · Page 9Linked to original sources
PubMed1983

An improved fixation technique for maintaining the fine structure of the nuclear zone of neonatal mouse lens.

The fine structure of the nuclear zone of neonatal mouse lenses can vary considerably according to the fixation used. When normal neonatal mouse lenses are fixed in a commonly used chilled glutaraldehyde solution, the nuclear zone develops a grossly visible opacity, and irregular sized protein granules appear in the subsequent sections. Similar artifacts of aggregated irregular sized protein granules appear when cataractous mouse lens are conventionally processed. These artifacts can be avoided by soaking the lens in 0.15 M reduced glutathione solution for 10-15 min before fixation in a phosphate buffered 2% glutaraldehyde solution (pH 7.4) at 27-35 C. Normal lenses treated in this manner maintain translucency in the nuclear zone throughout the fixation-embedding procedure, and the resulting sections show finely uniform granularity with the cell membrane well preserved. Similarly processed nuclear portions of cataractous lenses of Nakano mice show uniformly aggregated protein granules, measuring about 350A in diameter. The cell membranes in the cataractous zone are also not interrupted.

Animals↗
PubMed1982

The interaction of non-transforming Epstein-Barr virus (EBV) with cell-associated EBV DNA in superinfected lymphoblastoid cell lines.

Two human lymphoblastoid cell lines were established by the transformation of human cord-blood lymphocytes with transforming Epstein-Barr virus (EBV). One cell line (HLB-R1) was established with EBV obtained after the superinfection of Raji cells with HR-1 EBV and the other (HLB-Bl) was established from B95-8 EBV-infected human cord-blood lymphocytes. Both the HLB-R1 and HLB-B1 lines were susceptible to superinfection with HR-1 EBV. We found that EBV DNA was replicated in the superinfected cell lines and that transforming EBV was produced in both the HLB-B1 and HLB-R1 cells. The average titer of transforming EBV obtained in the HR-1 EBV superinfected HLB-B1 and HLB-R1 cell lines was 10(4) transforming units (TU)/ml, whereas the average titers of transforming EBV obtained by the superinfection of Raji cells was 10(1) TU/ml. Epstein-Barr virus capable of inducing early antigen (EA) in superinfected Raji cells (lytic virus) was not detected in any transforming virus preparation. Restriction enzyme digestion patterns of virus DNA isolated from HR-1 and B95-8 cells, as well as from superinfected cells, were compared. The EBV DNA that was replicated in the superinfected HLB-R1 and HLB-B1 cell lines showed a more complex pattern. Our data suggest that recombination between input HR-1 EBV DNA and latent cell-associated EBV DNA occurs. Presumably this recombination results in a change in the biological properties of the newly synthesized virus.

Burkitt Lymphoma↗
PubMed1982

Ambiguus motoneurons discharging closely associated with ultrasonic vocalization in rats.

Unitary discharges closely associated with ultrasound were recorded from the nucleus ambiguus (NA) and adjacent medullary regions in rats. Two main types of units were distinguished: one firing in tonic bursts against little or no background activity prior to ultrasound emission, and the other remaining silent during ultrasound. Tonic burst units in NA are considered as motoneurons which are essential for ultrasound vocalization since lesions including NA completely abolished its production.

Animals↗
PubMed1982

Effects of TRH on cell proliferation of rat pituitary cells (GH3).

Chronic treatment (more than 3 d) of GH3 cells, cloned rat pituitary cells producing prolactin, with 100 nM TRH resulted in a 41% reduction in the rate of cell growth in a medium containing 0.5% fetal bovine serum. These effects of TRH appeared both in the medium containing a higher concentration of serum and in that containing six growth factors, i.e. insulin, transferrin, parathyroid hormone, fibroblast growth factor, triiodothyronine, and multiplication-stimulating activity (MSA) instead of serum. TRH stimulated prolactin production by GH3 cells in a dose-dependent manner both in the serum-supplemented and serum-free media. On the other hand, TRH, at 1 nM, elicited a 130% stimulation in the cellular growth, whereas, at concentrations of more than 10 nM, it inhibited the growth significantly. In the defined culture system, it was demonstrated that TRH stimulated prolactin production in the presence or absence of six growth factors, whereas its inhibitory effects on cellular growth appeared only in the presence of MSA regardless of the presence or absence of the other five factors. Furthermore, it was shown that a dose-dependent stimulatory effect of MSA on the growth of GH3 cells was suppressed by TRH. TRH exhibited only a stimulatory effect on cellular growth in the medium containing the five factors other than MSA. In conclusion, TRH could inhibit cell growth of GH3 in the presence of MSA in the defined medium or MSA-like factor(s) in the serum-supplemented medium.

Animals↗
PubMed1982

Computed tomography in the diagnosis of fatty liver: total lipid content and computed tomography number.

Fifty-three histologically proved cases of various diffuse liver disease were studied for their computed tomography numbers (CTN). The machine used was Ohio Nuclear's Delta Scanner 50FS type and CTN was expressed by the Hounsfield unit (H). Mean CTN in each group was as follows: 66.6 +/- 2.6 H in normal control (N), 63.3 +/- 6.0 H in chronic hepatitis (CH). 61.8 +/- 7.0 H in liver cirrhosis (LC), and 44.4 +/- 10.6 H in fatty infiltration (FI). There were no significant differences among them except FI group. As N group were all above 60 H and CH and LC groups were all above 50 H, CTN below 60 H suggests chronic liver disease or fatty infiltration and CTN below 50 H strongly suggests fatty infiltration. In eleven cases where total lipid content of the liver could be be biochemically determined by the sulfo-phospho-vanillin reagent, a relation of total lipid content to CTN was studied. As a result, a significant correlation existed between them (r = -0.89; p less than 0.001). If the diagnostic criterion of fatty liver was set at total lipid content above 100 mg/g wet liver, CT criterion was estimated at CTN below 48 H from the regression formula.

Chronic Disease↗
PubMed1982

Diurnal fluctuation of blood ammonia levels in adult-type citrullinemia.

A 48-year-old man, who was diagnosed as adult-type citrullinemia by quantitative estimation of urea cycle enzymes in the liver, showed a regular nocturnal rise of blood ammonia level. In order to elucidate the mechanism of diurnal fluctuation of blood ammonia level, the patient was put into fasting state for four days. The blood ammonia level rose at the night of the first fasting day even though no food was taken, then it decreased gradually and reached the lowest level in the morning of the third fasting day. Intravenous administration of amino acids mixture under the same starved condition gave rise to a significant elevation of blood ammonia level. Based on these results, it was concluded that hyperammonemia of adult-type citrullinemia could result from the accumulation of free ammonia which was produced from the catabolism of amino acids absorbed from the small intestine and surpassed the urea synthesis of defective urea cycle to flood into the blood. Furthermore, the rise of blood ammonia level at the night of the first fasting day suggested that the circadian rhythm of amino acid-carbohydrate metabolism might superimpose on the process mentioned above.

Amino Acids↗
PubMed1981

Identification of ultrasonic vocalization substrates determined by electrical stimulation applied to the medulla oblongata in the rat.

The aim of the present investigation was to identify the neural structures, within the rat medulla, that are responsible for rodent ultrasound production. Sound producing substrates were found to be located in the reticular formation and some cranial nerve nuclei as well as several other nuclei situated in the lateral and dorsomedial portions of the medulla. To estimate the degree of involvement in the generation of ultrasound signals, the sound response latencies were measured for each structure. The lateral reticular nucleus and the facial nucleus showed latencies that were significantly shorter than those for other nuclei, and they were assumed to have a primary part in rodent ultrasound production. Audible sounds of considerably longer latencies were produced exclusively by stimulation of the trigeminal spinal tract nucleus. No ultrasounds could be obtained in this region. These results were discussed in terms of innervations of the facial and laryngeal musculature by the specific neural structures. Present results were also discussed with reference to the roles of the bulbar monoaminergic neurons projecting to the spinal cord and the role of ascending nociceptive pathways.

Animals↗