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Biomedical subjects

Y Hata

Publications and source records attributed to Y Hata.

At least 307 records · Page 17Linked to original sources
PubMed1992

An experimental study of ischemia following subcutaneous heterotopic intestinal graft: influence of arterial or venous occlusion.

A subcutaneously transferred intestinal model was prepared in the rat and experimental observations were conducted of serial histologic changes in the intestine and of acceptance rates, when the artery or vein in the pedicle was ligated at various times after transfer. Results showed 50 percent take in the artery-ligated group and 12.5 percent in the vein-ligated group, when performed 5 days after transfer; 87.5 percent take in the artery-ligated group and 50 percent in the vein-ligated group, when performed 7 days after transfer; and 100 percent take for both groups, when ligation was performed 14 days after transfer. Consequently, it was concluded that venous occlusion constitutes a greater danger to successful transfer of intestine than arterial occlusion.

Abdominal Muscles↗
PubMed1992

The effects of acid secretagogues on protective agents of gastric cells from adult rabbits in vitro.

Endogenous prostaglandin and mucus have been recognized as important protective factors in the gastric mucosa. However, the regulatory mechanisms of these agents have not been well studied. The aim of the present study was to investigate the effects of acid secretagogues on cyclic adenosine monophosphate (cAMP) formation, prostaglandin E2 (PGE2) production, and mucus secretion by isolated parietal cells and culture mucous cells from adult rabbits. Rabbit parietal cells were enriched by nonlinear Percoll gradients after the isolation of rabbit gastric mucosal cells with collagenase and ethylenediaminetetraacetic acid (EDTA). Rabbit gastric mucous cells were cultured in 10% fetal bovine serum added to Ham's F12 medium. As gastric acid secretagogues, histamine, carbachol, gastrin, and 2-chloroadenosine were tested. To evaluate the effects of the second messengers of cellular signal transduction on protective agents, A23187, which is a calcium ionophore, and cAMP were used. PGE2 and cAMP were measured by radioimmunoassay. The release of [3H]glucosamine from prelabeled cells was used as an indicator of mucus secretion. Histamine, carbachol, gastrin, and 2-chloroadenosine did not modulate PGE2 production by parietal cells. Exogenously administered cAMP did not affect PGE2 production by parietal cells, whereas it was significantly increased by A23187. 2-Chloroadenosine but not histamine or carbachol significantly increased cAMP formation by mucous cells. Histamine, carbachol, and gastrin did not have significant effects on PGE2 production by mucous cells. 2-Chloroadenosine, which increased cAMP, also did not modulate PGE2 production. A23187 but not cAMP increased PGE2 production by mucous cells. None of the acid secretagogues used in the present study modulated mucus secretion. A23187 but not cAMP significantly increased mucus secretion by cultured mucus cells.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Chloroadenosine↗
PubMed1992

Neurexins.

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed1992

Activity-dependent potentiation and depression of visual cortical responses to optic nerve stimulation in kittens.

1. To see whether long-lasting changes in synaptic efficacy are induced in the developing visual cortex (VC), field potentials evoked by test stimulation given alternatively to each of the optic nerves (ONs) were recorded from VC of kittens ranging in age from 4 to 8 wk. In some experiments, field potentials were recorded simultaneously from the dorsal lateral geniculate nucleus (LGN) in addition to VC. 2. Tetanic stimulation was applied to one of the ONs for 1-60 min at 5 Hz. Homosynaptic potentiation of cortical responses, defined as an increase lasting > 2.5 h in the cortical field potential evoked by test stimulation of the ON that was tetanized, was induced without any changes in LGN responses in 3 of the 12 kittens tested. Heterosynaptic depression, defined as a decrease lasting > 0.5 h in the field potential evoked by stimulation of the ON that was not tetanized, was also induced in two of those three kittens. 3. To elucidate a role of inputs originating from spontaneous activity of retinal ganglion cells in induction of potentiation and depression in the cortex, tetrodotoxin (TTX) was injected into both eyes of 11 kittens. After we confirmed the suppression of retinal activity by TTX, tetanic stimulation was applied to ON. Homosynaptic potentiation of cortical responses was induced in 6 of the 11 kittens, and the ratio of the mean amplitude of posttetanic responses to that of pretetanic responses for the 11 kittens was on average larger than that for the 12 control kittens. Heterosynaptic depression was not observed in any of the 11 kittens. 4. To see a role of postsynaptic activity in induction of potentiation and depression, gamma-aminobutyric acid (GABA) was applied continuously to the VC by an infusion pump in 10 kittens. Tetanic stimulation was given to ON while cortical activities were suppressed by GABA. After recovery of cortical activities, homosynaptic depression was found to be induced in 3 of the 10 kittens, but homosynaptic potentiation was not observed at all. The ratio of amplitude of posttetanic to pretetanic responses at the tetanized side for the 10 kittens was on average smaller than that for the 11 TTX-injected kittens. 5. These results can be accounted for by the modified covariance model in which the relation of postsynaptic activity and direction of changes in synaptic efficacy is formulated.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

[Protective effects of naftidrofuryl oxalate against hypoxia-induced death].

To analyze the effects of naftidrofuryl oxalate (LS-121) on the central nervous system exposed to critical hypoxia, survival duration was employed as a parameter of the protective effects of the drug against hypoxia-induced death. In the control group (no drug administration), the electroencephalogram (EEG) was flattened promptly after changing to hypoxia from aerobic conditions, and it was impossible to recognize precisely what time the EEG disappeared because of vigorous body movements. Arterial blood pressure (BP) was clearly recognized, and rats never recovered after BP decreased to 0 mmHg, although the electrocardiogram (ECG) was still recorded. Thus, survival duration recognized by measuring the time from the onset of hypoxia to the time when BP became 0 mmHg was considered to be a good indicator. After LS-121 (10 mg/kg) administration, survival duration was significantly prolonged compared to the control. Combination therapy of LS-121 (25 mg/kg) and bifemelane hydrochloride (BI) (25 mg/kg) also revealed the prolongation of survival duration. Neither idebenone (10 mg/kg) nor nicergoline (10 mg/kg) showed significant changes in survival duration. These findings suggest that LS-121, either with or without BI, could improve cerebrovascular disorders induced by hypoxia.

Animals↗
PubMed1992

[Study on the origin of vestibular neurons projecting to the spinal cord using retrograde labelling technique of horseradish peroxidase].

In spite of a large number of electrophysiological studies into the vestibulospinal (VS) effects on the spinal cord, there are far fewer anatomical studies on the VS projections. The present study was undertaken to determine the origins and descending pathways of VS neurons in the cat, using a retrograde labelling technique of horseradish peroxidase (HRP) combined with a lesion in the lower brainstem. HRP was applied unilaterally into the cervical or lumbar spinal cord and either the medial longitudinal fasciculus (MLF) or the lower medulla oblongata, sparing the MLF, was dissected. In all cases, HRP-labelled neurons were located in two distinct areas of the vestibular nuclear complex, the rostral and caudal areas. In the rostral area, HRP-labelled neurons after dissection of the MLF appeared in the ipsilateral lateral (LN), medial (MN) and descending nuclei (DN), on the same side as HRP insertion into the spinal cord, but somatotopical arrangement was not seen in the present study. Labelled neurons in the rostral part after impairment of a wide area of the lower medulla, though sparing the MLF, were seen bilaterally in the areas bordering the LN, MN, DN and superior nuclei. In the caudal area, HRP-labelled neurons were seen bilaterally in the caudal thirds of the MN and DN, and these projected to the lumbar spinal cord. Therefore the origins and descending pathways of the VS tracts were considered to be different from those shown in previous anatomical studies.

Animals↗
PubMed1992

[Cryptotia: morphometric characteristics and statistical observations].

PURPOSE: In the present study we made actual measurements of the normal and affected auricles of patients with unilateral cryptotia and performed a comparative statistical analysis. We also made a compilation of our own cases and other cases reported in Japan, and reported the results of our statistical analyses. METHODS: The subjects of this survey were 36 patients who came to our outpatient clinic with a chief complaint of cryptotia between 1983 and 1990. Measurements of auricle were made according to the Martin method. We also compiled all cases of cryptotia reported in the Japanese literature to date in which the sex of the patients and affected side were clearly recorded and reviewed associated abnormalities and familial occurrence. RESULTS: Auricle measurements of auricle showed the vertical axis of the affected auricle to be significantly shorter than normal, revealing severe shortening of the upper 1/3 of the auricle. There was no statistically significant difference between the normal and affected auricles on the horizontal plane. The results of our compilation of reports in the literature to date show a male-female ratio of 2:1, a right-left-bilateral ratio of 5:2:3, the presence of other anomalies in 9.2% (7/76), and familial occurrence in 6.4% (15/236). CONCLUSIONS: (1) Based on measurements of auricle, cryptotia is defined as a deformity of the upper 1/3 of the auricle and is produced by the sum total of force vectors operating inferiorly and medially. Moreover, based on the data obtained as a result of the measurements performed in this study, there was greater deformity along the vertical axis, and the downward vector was obviously stronger than the inward vector. (2) There were 3 cases of unilateral cryptotia with an adhesion-like deformity of the helix in the normal ear, and the theory that the upper portion of the auricle becomes embedded secondary to cartilage deformity seemed plausible. (3) A compilation of cases in Japan showed a male-female ratio of 2:1 and a right-left-bilateral ratio of 5:2:3, differing little from the ratios in our cases. (4) Familial occurrence in our cases was found in the patient's mother of 2 cases and a male cousin and uncle in 1 case each, suggesting a strong hereditary influence.

Adolescent↗
PubMed1992

[Nosocomial respiratory infection caused by Pseudomonas cepacia in immunocompromised hosts].

Pseudomonas cepacia is a gram negative rod, having no fermentative activity on glucose. This organism was detected in the sputum, throat swab, or throat washing of 22 inpatients treated between January, 1990, and December, 1990, at the First Department of Internal Medicine, Kagawa Medical School. The primary diseases for which these 22 patients were hospitalized were leukemia in 12, malignant lymphoma in 5, lung cancer in 2, myelodysplastic syndrome in 1, and embryonal cell carcinoma in 1. Twelve of the 22 patients had episodes of pneumonia which complied clinically with the diagnostic criteria provided to facilitate the National Nosocomial Infection Study. The complication of pneumonia occurred in 7 patients with leukemia, 2 with malignant lymphoma, 2 with lung cancer, and 1 with myelodysplastic syndrome. In 10 of these 12 patients, the organism was detected before the onset of pneumonia. All 22 patients in whom the organism was demonstrated had received antibiotics. The antibiotics which was most frequently used to treat these patients 1 month before detection of Pseudomonas cepacia were amikacin and ceftizoxime, which were used in 13 patients. Of the antibiotics in which the susceptibility to Pseudomonas cepacia was, evaluated, minocycline was effective in 100% (21/21), ceftazidime in 50% (11/22), and ofloxacin in 27.3% (6/22). Physicians should be especially aware of the possibility of colonization and nosocomial respiratory infection by Pseudomonas cepacia in patients with severe underlying diseases.

Adolescent↗
PubMed1992

Heat distribution in bone during preparation of implant sites: heat analysis by real-time thermography.

The purpose of this experiment was to observe and measure the distribution of heat to bones and the maximum temperature that developed when cutting bone with drills. Generation of heat that spread in the presence or absence of irrigation when drilling with IMZ, Brånemark, and ITI implant (F type) drills was observed in the pig rib via thermography. Without irrigation, the condition of heat spread in each drill and bur differed according to bur shape and drilling site. Maximum heat temperature without irrigation was higher than that with irrigation for any IMZ, ITI, and Brånemark drill.

Animals↗
PubMed1992

E. coli gpt gene expression effects on K562 human leukemia cell proliferation and erythroid differentiation altered by mycophenolic acid.

Inosine monophosphate dehydrogenase (IMPDH, EC 1.1.1.205) inhibitors including mycophenolic acid (MPA) were reported to induce K562 human leukemia cells to differentiate into erythroid cells. A shuttle vector plasmid pMSG containing E. coli xanthine-guanine phosphoribosyl transferase (Eco gpt) gene was transfected into K562 cells (K562-pMSG cells) to investigate the role of IMPDH in both K562 cell proliferation and erythroid differentiation. Eco gpt provides K562 cells with an additional salvage pathway for GMP production from xanthine. In the presence of xanthine, K562-pMSG cells continued to proliferate and did not differentiate to erythroid cells regardless of the presence of MPA, but they discontinued proliferating and differentiated into the erythroid lineage in the absence of xanthine. Proliferation and differentiation of control K562 cells into erythroid cells were suppressed by MPA regardless of the presence or absence of xanthine. Addition of guanosine maintained the proliferation and blocked the erythroid differentiation of K562 and K562-pMSG cells induced by MPA even in the absence of xanthine. These data indicate that a decrease in the activity of IMPDH and a subsequent decline in the concentration of guanine nucleotides caused by MPA resulted in the induction of the erythroid differentiation and discontinuation of the proliferation of K562 cells.

Blotting, Southern↗
PubMed1991

Flow cytometric analysis of the nuclear DNA content of hepatoblastoma.

The nuclear DNA content of 15 hepatoblastoma cases was determined in paraffin-embedded tissues by flow cytometry. The DNA index (DI) was calculated, and the ploidy pattern of nuclear DNA was estimated. The correlation between the ploidy pattern and clinicopathologic findings was studied, and the prognostic significance of the ploidy pattern was investigated. An aneuploid pattern was seen in 50% of the lesions with histologic embryonal and anaplastic types. It was not seen in the fetal type. In the tumors with combined epithelial components, the fetal-type component had a diploid pattern in all five cases. The embryonal-type component was associated with aneuploidy in two of five cases. In aneuploid tumors, vascular invasion (tumor emboli in the vessels) was observed more frequently. The prognosis of the patients with an aneuploid tumor was significantly poorer. These results indicate that nuclear DNA ploidy pattern analysis might be useful in investigating the prognosis of hepatoblastoma.

Carcinoma, Hepatocellular↗
PubMed1991

Nucleotide sequence and expression of the glucoamylase-encoding gene (glaA) from Aspergillus oryzae.

The glucoamylase-encoding gene (glaA) from Aspergillus oryzae was cloned using its cDNA as a probe, which had been isolated previously. From comparison of nucleotide (nt) sequences of genomic clones with its cDNA, the glaA gene was found to contain four short putative introns, 45-56 nt in length. The A. oryzae glaA gene shared 62% homology at the nt level with the A. niger glaA gene with the four introns located at the same position. The 5'-flanking region contained a TATA box at nt-72 from the start codon, and two putative CAAT sequences at nt-87 and -331. Genomic Southern analysis and physical mapping showed that the glaA gene is located on the smallest chromosome (3.4 Mb) of six separated bands of chromosomes. Clones containing the glaA gene, when re-introduced intro A. oryzae, resulted in a three- to eightfold increase in glucoamylase activity.

Amino Acid Sequence↗
PubMed1991

Induction of erythroid differentiation of K562 cells by 4-carbamoylimidazolium 5-olate (SM-108).

The effects of 4-carbamoylimidazolium 5-olate (SM-108), an antipurine compound, on a human leukemia cell line, K562, were studied. Treatment with SM-108 induced erythroid differentiation of K562 cells. During a 6-day culture with 100 microM SM-108, the cell number decreased to 37% of the control number, 77% of the cells became benzidine-positive, and the hemoglobin content increased from 2.1 +/- 0.2 to 10.6 +/- 1.3 pg/cell. Cell differentiation was associated with reduction of IMP dehydrogenase activity and intracellular GTP content to 25 and 36%, respectively, of the control values within 1.5 hr. The differentiation and decrease in the GTP pool induced by SM-108 were blocked by the presence of 25 microM guanine or guanosine. SM-108 also induced erythroid differentiation of K562 subline cells transfected with pMSG (K562/pMSG), which have an additional salvage pathway for GMP production from xanthine. The addition of 100 microM xanthine prevented erythroid differentiation of this subline and restored the GTP pool. These findings suggest that the induction of erythroid differentiation of K562 cells by SM-108 may be due to an early decrease in IMP dehydrogenase activity and a subsequent decrease in GTP content in the cells. Thus, purine metabolism may have an important role in SM-108-induced differentiation.

Cell Differentiation↗
PubMed1991

Percutaneous ethanol injection therapy for hepatocellular carcinoma. A histopathologic study.

Histopathologic examination was done on 18 cases after percutaneous ethanol injection therapy (PEIT) for hepatocellular carcinoma. In eight cases, the lesion was treated by PEIT alone; in the other ten cases, PEIT was combined with transcatheter arterial embolization. The lesion was completely necrotic in 13 cases, 90% necrotic in four cases, and 70% necrotic in the rest. In addition, PEIT seemed to be effective against intercapsular, extracapsular, and vascular invasions. In the four cases of incomplete necrosis, the viable cancer tissue remained in small tumor nodules around the main tumor, in portions isolated by septa, or along the edge of the lesion. Therefore, ethanol should be injected not only into the center of the lesion, but also into sites close to its edge. Ethanol did not damage noncancerous liver parenchyma distant from injected sites. Local dissemination of the cancer cells was not found in any case. Therefore, PEIT seems to be a valuable therapy and may be an alternative to surgery in some cases.

Adult↗