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Biomedical subjects

Y Kojima

Publications and source records attributed to Y Kojima.

At least 19 recordsLinked to original sources
PubMed1992

Bilateral innervation of the musculus levator palpebrae superioris by single motoneurons in the monkey.

The location of motoneurons innervating the musculus levator palpebrae superioris (LPS) was studied in the monkey (Macaca irus) by using Fast blue (FB) and propidium iodide (PI) as retrograde neuronal tracers. In each monkey, FB was injected into the LPS of one eye and PI into the LPS of the other eye. Neuronal cell bodies labeled with FB and/or PI were seen intermixed bilaterally through the entire rostrocaudal extent of the central caudal nucleus. While single-labeled (70%) cell bodies predominated, many double-labeled (30%) cell bodies were also encountered. Each of the double-labeled neurons was concluded to supply the LPS on both sides by way of axon collaterals.

Animals↗
PubMed1992

Inhibition of tumor invasion and extracellular matrix degradation by ubenimex (bestatin).

We have investigated the effect of the immunomodulator ubenimex (hereafter referred to as bestatin) on the enzymatic degradation of the extracellular matrix by human renal cell carcinoma SN12M cells during the invasive process. The invasion of SN12M cells into reconstituted basement membrane (Matrigel) was inhibited by the presence of bestatin in a concentration-dependent manner. However, bestatin did not have any effect on tumor cell adhesion and migration to the extracellular matrices which may be involved in tumor cell invasion. Bestatin inhibited the degradation of type IV collagen by tumor cells, but not by tumor-conditioned medium (TCM), in a concentration-dependent manner. We also found that bestatin inhibited hydrolysing activities towards substrates of aminopeptidases in SN12M cells. Since bestatin was found to inhibit aminopeptidase activity, the inhibition of tumor invasion by bestatin is likely to be associated with its action as an enzyme inhibitor. Bestatin only slightly inhibited tumor cell plasmin activity, which can lead to the conversion of the latent collagenase to the active form, but this slight effect was not significant. The zymography of TCM from SN12M cells showed that the treatment of tumor cells with bestatin resulted in the disappearance of the 68 kDa type IV collagenase-enzyme level (active form) and slight reduction of the 72 kDa type IV collagenase-enzyme level (latent form). These results indicated that bestatin may inhibit tumor cell invasion through a mechanism involving its inhibitory action on aminopeptidases in tumor cells, suggesting that the aminopeptidase may partly be associated with the conversion of a latent form of type IV procollagenase to an active form or the secretion of the collagenases from tumor cells.

Adult↗
PubMed1992

A case of duodenal carcinoma presenting as a submucosal tumor.

This paper describes a patient with duodenal carcinoma showing the features of a submucosal tumor, leading to difficulty in making an accurate preoperative diagnosis. A 63-year-old woman was admitted for investigation of a duodenal mass. An examination of the upper gastrointestinal tract revealed a semicircular compression of the stomach and the duodenum. Endoscopy of the stomach and duodenum disclosed a hemispherical tumor with a deep ulcer in the apex. Computer tomography revealed a tumor of about 5 cm in diameter at the same site. Laparotomy was performed under the tentative diagnosis of a submucosal tumor. A tumor was found occupying the duodenum, which compressed the gastric antrum exteriorly, and was also adherent to the head of the pancreas by direct invasion. A curative resection was performed by combining a pancreatoduodenectomy with a transverse colectomy along with regional lymph node clearance. A microscopic examination showed that the tumor contained neoplastic cells growing in a tubular pattern, particularly in its peripheral regions. Thus, this lesion was finally diagnosed as primary adenocarcinoma of the duodenum.

Adenocarcinoma↗
PubMed1992

Postoperative complications and survival after pancreatoduodenectomy in patients aged over 70 years.

An analysis of postoperative complications and survival was conducted in 31 patients undergoing pancreatoduodenectomy (PD) for carcinoma of the pancreas or periampullary carcinoma. Of them, 11 were over 70 years of age and 20 were under 70. Anastomotic leakage was the most common complication after PD. Definite pancreatic leakage was found in one patient in the over 70 group, and one case each of pancreatic, biliary, and gastric leakage were found in the under 70 group. All complications were treated conservatively without any further operative intervention. The overall morbidity rate was 41.9% (13/31), being 45.5% (5/11) in the over 70 group and 40.0% (8/20) in the under 70 group, and no operative deaths occurred within 30 days after surgery. The cumulative survival rate of the patients aged over 70 years with carcinoma of the pancreas or periampullary carcinoma did not differ significantly from the rate of those under 70. It was thus concluded that PD achieves an adequate prognosis and survival in patients over 70 years of age.

Adult↗
PubMed1992

Verbal versus non-verbal visual evoked potentials: Kanji versus line drawings.

Cortical areas related to perception of verbal and non-verbal stimuli were studied using VEPs. Kanji characters, line drawings (LD), or a blank were displayed. Verbal VEPs were obtained by subtracting the blank-VEPs from the Kanji-VEPs, and non-verbal VEPs by subtracting the blank-VEPs from the LD-VEPs. Both the verbal and non-verbal VEPs showed a negative peak (100-300 msec) focally over bilateral occipital, posterior temporal and parietal areas, and a positive peak diffusely over frontal halves. Differences between the non-verbal from the verbal VEPs showed an initial peak (100-200 msec) focally over bilateral occipital and posterior temporal areas, followed by a peak (200-300 msec) focally over bilateral posterior temporal areas. The frontal areas diffusely showed peaks at 100-200, 200-300 and 300-400 msec. Left-right asymmetries of both the verbal and non-verbal VEPs showed peaks between 100 and 300 msec over posterior temporal, parietal, and occipital areas. Left-right asymmetries of the subtraction to the non-verbal from the verbal VEPs showed a peak (100 msec) over occipital and parietal areas, and a broader peak over posterior temporal area (100-200 msec). Bilateral occipital, posterior temporal, and parietal areas are focally activated by the two perceptions (100-300 msec), while frontal areas are activated diffusely. Further, different processes may be focally involved between the hemispheres over occipital (100-200 msec) and posterior temporal (100-200 and 200-300 msec) regions. Initial left-right asymmetries of the subtracted VEP between the two perception would occur over occipital and parietal areas (100 msec) and last for 200 msec over posterior temporal area.

Acoustic Stimulation↗
PubMed1992

Nonspecific esophageal motor disorder associated with thickened muscularis propria of the esophagus.

A case of a nonspecific esophageal motor disorder associated with muscular hypertrophy, revealed by endoscopic ultrasonography, is reported. A 41-year-old man was admitted to the hospital with chest pain and dysphagia. Manometric studies of the esophagus disclosed prolonged duration of propulsive waves with normal amplitude. Endoscopic ultrasonography showed downward thickening of the esophageal muscular layer; the maximum thickness was found at the lower esophageal sphincter. Thickening of the esophageal wall of unknown etiology has been reported as a diffuse esophageal muscular hypertrophy. Previous cases of diffuse esophageal muscular hypertrophy were diagnosed by autopsy. Some cases involved dysphagia and/or chest pain. Therefore, some of the reported cases of nonspecific esophageal motor disorders may have been associated with diffuse esophageal muscular hypertrophy. Association of the two categories was shown by endoscopic ultrasonography for the first time in the present case. Endoscopic ultrasonography is a useful tool for the diagnosis of the thickening of the muscular layer of the esophagus.

Adult↗
PubMed1992

Detection of hepatitis C virus RNA by nested polymerase chain reaction in sera of patients with chronic non-A, non-B hepatitis treated with interferon.

To evaluate the effect of interferon-alpha treatment on the levels of serum aminotransferase (sALT) and of hepatitis C virus (HCV)-RNA, we studied 19 patients with chronic non-A, non-B (NANB) hepatitis. Before therapy, 14 patients were positive by nested polymerase chain reaction (PCR) with primers deduced from the 5'-non-coding region of the HCV genome. Serum HCV-RNA had disappeared in 12 (85.7%) of them by the end of therapy, but then reappeared 6 months later in 4 of these 12 patients. A marked improvement in sALT was seen in 5 of the 8 patients with sustained HCV-RNA disappearance, but not in the 4 patients with only transient HCV-RNA negativity. Pre-treatment levels of hepatitis C viremia, analyzed by single PCR and dot blot hybridization, ranged from 2 x 10(3) to 2 x 10(8) copies/ml, and were below 2 x 10(5) copies/ml in patients with a complete response to interferon therapy. These results suggest that this HCV-RNA assay, combined with sALT testing, may be useful for estimation of the long-term efficacy of interferon therapy in hepatitis C.

Adult↗
PubMed1992

Large scale cDNA sequencing for analysis of quantitative and qualitative aspects of gene expression.

Large scale sequencing of cDNAs provides a complementary approach to structural analysis of the human genome by generating expressed sequence tags (ESTs). We have initiated the large-scale sequencing of a 3'-directed cDNA library from the human liver cell line HepG2, that is a non-biased representation of the mRNA population. 982 random cDNA clones were sequenced yielding more than 270 kilobases. A significant portion of the identified genes encoded secretable proteins and components for protein-synthesis. The abundance of cDNA species varied from 2.2% to less than 0.004%. Fifty two percent of the mRNA were abundant species consisting of 173 genes and the rest were non-abundant, consisting of about 6,600 genes.

Base Sequence↗
PubMed1992

Evidence of direct generation of oxygen free radicals from heterocyclic amines by NADPH/cytochrome P-450 reductase in vitro.

Highly purified cytochrome P-450 reductase (also called cytochrome c reductase; EC 1.6.2.4.) and NADPH were used to generate superoxide radical (O2.-) from 11 different heterocyclic amines (HCAs) as identified by electron spin resonance spectroscopy using the spin trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The signal intensity of DMPO-OOH(-O2-) (i.e., the DMPO spin adduct of O2.-) was strongest for 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ). The O2.- generation with HCAs decreased in the following order: 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx) = 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) > 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (diMeIQx) > or = other HCAs; O2.- generation was lowest with 2-amino-3-methyl-9H-pyrido[2,3-b]indole .CH3COOH (MeA alpha C). By using Lineweaver-Burk plots, Km values of cytochrome P-450 reductase for mitomycin C, IQ, and MeIQ were determined to be 1.60 x 10(-6) M, 1.97 x 10(-5) M, and 2.83 x 10(-6) M, respectively. The present findings have important implications for carcinogenesis because of the known effect of oxygen radicals on cell proliferation.

Amines↗
PubMed1992

Combined use of silver staining of the retrograde tracer WGAapoHRP-Au and pre-embedding immunocytochemistry for electron microscopy: demonstration of dopaminergic terminals in synaptic contact with striatal neurons projecting to the substantia nigra in the rat.

We investigated the applicability of the pre-embedding immunoperoxidase technique to WGAapoHRP-Au retrograde tracing. After injection of the tracer into the substantia nigra of rat, the brain was fixed and cryostat sections were immunostained for dopamine. The sections were osmicated and silver-stained to amplify the colloidal gold particles. Products of both the immunoperoxidase staining and the silver staining could be detected and distinguished by electron microscopy at low magnification. The ultrastructure was so well preserved that synaptic characteristics could be investigated. Dopaminergic terminals were demonstrated to synapse with striatal neurons projecting to the substantia nigra.

Animals↗
PubMed1992

Lactotrophs secreting small amounts of prolactin reveal great responsiveness to thyrotropin-releasing hormone: analysis by the sequential cell immunoblot assay.

The effects of TRH on PRL secretion from individual lactotrophs of female rats were investigated by using a sequential cell immunoblot assay. The same pituitary cells cultured on coverslips were first incubated to determine basal secretion of PRL and subsequently challenged by one of various concentrations of TRH. The PRL secreted from the single lactotrophs was absorbed on protein-blotting transfer membranes, immunostained, and quantified by microscopic image analysis. When no TRH was added to the medium used in the second incubation (controls), the amount of PRL secreted from individual lactotrophs was 93% of that secreted in the first incubation. Treatment with 3 x 10(-10)-10(-7) M TRH in the second incubation increased in a dose-dependent manner the proportion of lactotrophs whose PRL secretion was significantly greater than confidence limits for PRL secretion in the controls. However, the percentage of TRH-responsive lactotrophs remained less than 50% even at a maximally effective concentration of TRH. Proportions of the TRH-responsive lactotrophs were significantly greater in cells that secreted small amounts of PRL under basal conditions than in those that secreted large amounts. Furthermore, the small, but not the large, secretors showed a significant increase in mean absolute amounts of PRL secreted by 10(-7) M TRH, which represented no less than 45% of all PRL secreted from the lactotroph population by the TRH treatment. These results indicate that 1) there is a heterogeneity with respect to lactotroph responsiveness to TRH and that 2) a population of lactotrophs that secrete small amounts of PRL under basal conditions contains a much larger proportion of TRH-responsive lactotrophs than does a population of lactotrophs that secrete large amounts of PRL.

Animals↗
PubMed1992

Ultrastructure of goat testes: intercellular bridge between germ cells.

The fine structure of intercellular bridge (ICB) of goat germ cells was studied using testicular samples fixed by perfusion. In the seminiferous tubules, the ICBs were observed between sister cells of spermatogonia, spermatocytes and spermatids. As a result of incomplete division of germ cells, the ICB first appeared as a midbody containing a remnant of the bundle of microtubules (spindle fibers). These microtubules then disappeared and were replaced by a shutter apparatus which was composed of multiple lamellar cisternae (bridge-partitioning complex). The inner part of the ICB was reinforced with a layer of electron dense mass (bridge density) which persisted up to the residual cytoplasm of spermiation. After complete reconstruction of the sister cells, the cisternae of the bridge-partitioning complex disappeared and the channel of the ICB was opened. Evidently (see electron micrographs), almost all of the cytoplasmic organelles could pass through the channel of the ICB. In the longitudinal section, the appearance of the ICBs between sister spermatogonia and between sister spermatocytes was observed as a double linear or drum shape, and that between sister spermatids was noticed as a horseshoe-like or concave formation. With the process of spermatogenesis, the ICBs gradually became widened and shortened. The functional significance of the ICB in the goat was discussed.

Animals↗
PubMed1992

Effects of pig follicular fluid on maturation of pig oocytes in vitro and on their subsequent fertilizing and developmental capacity in vitro.

This study examines the effects of pig follicular fluid on the maturation of pig oocytes and on their subsequent fertilizing and developmental capacity in vitro. The addition of pig follicular fluid or its fractions obtained by ultrafiltration, gel filtration and ion-exchange chromatography to maturation medium significantly increased the rates of nuclear maturation, normal fertilization and normal cleavage of pig oocytes after fertilization in vitro: the rates of normal fertilization and cleavage were 2-4 times higher than those in the control medium. The efficacy of pig follicular fluid was lost after heating at 56 degrees C for 30 min, whereas no significant decrease in activity was observed after defatting. In addition, the effective component(s) was partially purified by ultrafiltration, gel filtration and ion-exchange chromatography: the activity was observed in the fraction (UF2; M(r) 10,000-20,000) obtained by ultrafiltration. Activity was found in the first fraction (G1) obtained by gel filtration of UF2. Among three fractions obtained by ion-exchange chromatography of G1, only the third fraction had the activity. The results indicate that pig follicular fluid contains an acidic substance(s) (M(r) 10,000-200,000) that promotes oocyte maturation.

Animals↗
PubMed1992

Effects of the M1 muscarinic receptor antagonist pirenzepine on gastric mucus glycoprotein in rats with or without ethanol-induced gastric damage.

Changes in gastric mucus glycoprotein (mucin) isolated from pirenzepine-treated rats with or without ethanol (50%)-induced gastric damage were studied. The prior administration of pirenzepine inhibited significantly and dose-dependently the occurrence of macroscopically observable hemorrhagic lesions induced by treatment with ethanol. The gastric mucosa was separated into the surface mucosa, including the mucus gel layer, and the deeper mucosa by mechanical scraping, and the mucin in each was isolated. In ethanol-treated animals the mucin content of the deep corpus mucosa was significantly reduced to 68% the control value. This reduction was inhibited by pretreatment with pirenzepine. In the surface mucosa mucin content was also reduced to 48% of control value by ethanol treatment, but pirenzepine pretreatment increased mucin content to 235% the control value. Total mucin content in the entire stomach essentially resumed the control level by pretreatment with 100 mg/kg of pirenzepine. A single oral administration of pirenzepine (100 mg/kg) caused no change in total mucin content, but mucin in the deep corpus mucosa selectively and significantly increased to 124% the control. These and the results of carbohydrate analysis of purified mucin indicate that pirenzepine administration possibly accelerates the secretion of accumulated deep corpus mucus, retains this deep mucus on surface mucosal mucus, and protects the gastric mucosa in ethanol-induced gastric damage. This may be related to the antiulcerogenic effects of pirenzepine.

Animals↗
PubMed1992

CP-82,009, a potent polyether anticoccidial related to septamycin and produced by Actinomadura sp.

A new polyether antibiotic CP-82,009 (C49H84O17) was isolated by solvent extraction from the fermentation broth of Actinomadura sp. (ATCC 53676). Following purification by column chromatography and crystallization, the structure of CP-82,009 was elucidated by spectroscopic (NMR and MS) methods. The absolute stereochemistry was determined by a single crystal X-ray analysis of the corresponding rubidium salt. CP-82,009 is among the most potent anticoccidial agents known, effectively controlling the Eimeria species that are the major causative agents of chicken coccidiosis at doses of 5 mg/kg or less in feed. It is also active in vitro against certain Gram-positive bacteria, as well as the spirochete, Serpulina (Treponema) hyodysenteriae.

Actinomycetales↗