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Biomedical subjects

T Nishi

Publications and source records attributed to T Nishi.

At least 217 records · Page 12Linked to original sources
PubMed1993

The effect of fructose on fructose 2,6-bisphosphate level and fructose 6-phosphate, 2-kinase activity in the perfused rat liver.

In order to investigate the effect of fructose on the metabolic rates of liver glycolysis, changes in fructose 2,6-bisphosphate content and fructose 6-phosphate, 2-kinase (F6P2kinase) activity were examined using perfused rat liver. When the starved liver was perfused with 0.5 mM fructose, the fructose 2,6-bisphosphate level was 6.66 nmol/g liver, or the maximum. However, with further increases in the fructose concentration, increments in the fructose 2,6-bisphosphate level gradually decreased. F6P2kinase was inactive in the starved rat liver. By perfusion with the medium containing fructose or even without fructose, however, the enzyme was activated. The suppression of the increase in the fructose 2,6-bisphosphate level by perfusion at higher fructose concentrations was at least partly due to the inhibition of F6P2kinase by F1P.

Adenosine Triphosphate↗
PubMed1992

Salt tolerance and glycerol accumulation of a respiration-deficient mutant isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii.

A respiration-deficient (RD) mutant was isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii. One strain among sixteen glycerol-non-utilizing mutants exhibited vigorous liberation of CO2 but no uptake of O2. Furthermore, this strain lacked cytochrome aa3 and had a reduced level of cytochrome b. The few mitochondria found in cells of this strain contained few or no cristae. Salt tolerance and intracellular accumulation of glycerol by the RD strain were almost equal to that of the wild-type strain in media containing NaCl up to 2.5 M. In media with more than 3 M NaCl, the growth of the RD mutant was retarded and the intracellular accumulation of glycerol was depressed in spite of ample production.

Adaptation, Biological↗
PubMed1992

Sequence motif in control regions of the H+/K+ ATPase alpha and beta subunit genes recognized by gastric specific nuclear protein(s).

A nuclear protein(s) from rat or pig stomach recognized a conserved sequence in the 5'-upstream regions of the rat and human H+/K(+)-ATPase alpha subunit genes. A gel retardation assay suggested that part of the binding site was located in the TAATCAGCTG sequence. No nuclear proteins capable of the binding could be detected in other tissues of rat (liver, brain, kidney, spleen and lung) or pig liver. The sequence motif (GATAGC) located 5'-upstream of the beta-subunit gene also seemed to be recognized by the same protein, because the binding of nuclear protein to the sequence motifs in the alpha and beta subunits was mutually competitive. Considering the sense-strand sequence of the binding motif in the alpha-subunit gene, we conclude that (G/C)PuPu(G/C)NGAT(A/T)PuPy is a core sequence motif for the gastric specific DNA binding protein (PCSF, parietal cell specific factor).

Adenosine Triphosphatases↗
PubMed1992

Alternative splicing of neurofibromatosis type 1 gene transcript in malignant brain tumors: PCR analysis of frozen-section mRNA.

The neurofibromatosis type 1 (NF1) gene encodes a 360-residue region showing significant homology to the catalytic domains of both mammalian GTPase-activating protein (GAP) and yeast IRA protein. The product of the GAP-related domain of the NF1 gene (NF1-GRD) has been shown to stimulate ras GTPase and consequently to inactivate ras protein. We previously reported that the NF1-GRD has two types of transcripts, type I and type II, which are generated by an alternative splicing mechanism, and that the differential splicing of the NF1-GRD may be related to differentiation of neuroectodermal cells. Here we examined the differential expression of type I and type II transcripts of NF1-GRD in clinical samples of supratentorial malignant brain tumors by the RNA-polymerase chain reaction (PCR) method using frozen tissue sections. Our observations revealed that normal cerebrum predominantly expressed the type II NF1-GRD transcript, whereas primitive neuroectodermal tumors predominantly expressed the type I transcript. Additionally, although the type I/type II ratio in astrocytomas varied widely among tissue samples, all glioblastomas showed higher type I/type II ratios than adjacent brain samples. The RNA-PCR analysis using frozen tissue sections is a useful and sensitive method for detecting genetic markers in clinical tissue samples.

Astrocytoma↗
PubMed1992

Anorectal anomalies associated with Kabuki make-up syndrome.

A case report of a 3-year-old girl with Kabuki make-up syndrome (KMS) associated with anovestibular fistula is presented. To our knowledge, 62 patients with KMS have been reported in the literature, three of whom were described as having an anorectal anomaly. Including the present patient, all four KMS patients were females with anovestibular fistula.

Abnormalities, Multiple↗
PubMed1992

Ovarian juvenile granulosa cell tumor associated with Maffucci's syndrome.

A 15-year-old girl developed a juvenile granulosa cell tumor associated with Maffucci's syndrome (enchondromatosis + hemangiomas). Clinical manifestations of the disease included an abdominal mass and progressive anemia. She underwent the removal of a Stage Ic juvenile granulosa cell tumor and subsequent adjuvant chemotherapy. On follow-up examination 4 years later, no recurrence of the ovarian tumor was noted. A review of the literature showed 10 previous cases of juvenile granulosa cell tumor associated with enchondromatosis, two associated with Maffucci's syndrome, and the rest with Ollier's disease (enchondromatosis). Ovarian juvenile granulosa cell tumor may occur not infrequently in female patients with enchondromatosis in the first or second decades, in contrast to the widely recognized sarcomatous changes of enchondromas that usually occur after the second decade. Data provided from these cases also emphasize the concept of a generalized mesodermal dysplasia.

Adolescent↗
PubMed1992

Intracranial extension of an orbital pseudotumor accompanied by internal carotid artery occlusion--case report.

A rare case of histologically verified orbital pseudotumor with intracranial extension in a 33-year-old male is reported. Preoperative radiographs showed the mass extending beyond the orbit and involving the bilateral cavernous sinuses. The intracranial lesion at biopsy surrounded the right internal carotid artery above the right cavernous sinus. Cerebral angiography showed complete occlusion of the cervical portion of the right internal carotid artery. Possibly, multiple lesions had extended contiguously through the venous system around the cavernous sinus, with subsequent involvement of the internal carotid artery. This case suggests that orbital pseudotumor may not be a separate clinical entity, but a part of the syndrome caused by inflammation of the venous system around the cavernous sinus.

Adult↗
PubMed1992

[Breast conservation treatment of early breast cancer--eight-year experience].

In the period between 1983 and 1991, we experienced 80 cases of early breast cancer treated by conservative surgery and postoperative radiotherapy. Our indications for breast conservation treatment are the size of tumor (less than 2 cm), the location (more than 3 cm away from the nipple) and no palpable axillary nodes. Our surgical procedures of quadrantectomy and level I and II axillary dissection are presented. The shape of the skin incision should be elliptical with the major axis radial from the nipple for good cosmetic results. The entire quadrant of the breast containing the primary carcinoma is radically removed with the superficial pectoralis fascia. At present, one breast recurrence and two distant metastases have developed. A further follow up study is needed to prove the safety of breast conservation treatment.

Adult↗
PubMed1991

Complete primary structure of porcine tenascin. Detection of tenascin transcripts in adult submaxillary glands.

Tenascin is an extracellular matrix protein that is postulated to modulate tissue differentiation and cell migration during development. cDNA clones for tenascin were isolated from a cDNA library of adult porcine submaxillary glands. Three forms of tenascin clones were observed which varied with the number (8-10) of fibronectin type III (FN-III) domains. A major form consists of the N-terminal domain involved in the hexamer formation of tenascin subunits, 14 epidermal-growth-factor-like domains, nine FN-III domains, and the fibrinogen-like domain. A minor form with ten FN-III domains has never been described. Another striking feature is the lack of an RGD sequence that has been implicated to be crucial for cell adhesion, whereas RGD is present in both chicken and human tenascin sequences. In the adult, tenascin is expressed in very restricted tissues such as brain and chicken gizzard. A survey of tenascin transcripts in various adult rat normal tissues, including brain, revealed that the transcripts were detected only in submaxillary glands where tenascin expression has never been reported.

Amino Acid Sequence↗
PubMed1991

Roles of cyclic GMP and inositol trisphosphate in phototransduction of the molluscan extraocular photoreceptor.

The internal messengers mediating the photocurrent of the molluscan extraocular photoreceptor, A-P-1, were examined. In the dark, pressure-injection of cGMP into the A-P-1, voltage-clamped at resting levels, produced a rapid outward current, associated with an increase in conductance. However, the cGMP-induced current and increase in conductance were suppressed by subsequent photostimulation, suggesting hydrolysis of cGMP by light. The steady-state I/V relation for the cGMP-induced current was non-linear. The I/V relation for the instantaneous cGMP-induced current, measured 50 ms after the beginning of a voltage step, was linear, and reversed at the membrane potential, -67 mV, which corresponded to the K+ equilibrium potential of A-P-1 in 10 mM K+ normal saline. These findings indicate that the internal cGMP induces a voltage- and time-dependent K+ current. Since the photocurrent results from the suppression of a voltage- and time-dependent K+ current similar to above, the photocurrent is considered to be equivalent to the suppression of the cGMP-induced current. Short pressure-injection of GDP-beta-S into A-P-1 reduced the subsequent photocurrent. The photocurrent was also suppressed after an external application of Pertussis toxin. On the other hand, the photocurrent was amplified by prior pressure-injection of inositol 1,4,5-trisphosphate (IP3). However, a short pressure-injection of neomycin into A-P-1 depressed the subsequent photocurrent. These results suggested that the cGMP-induced (dark) current is mediated by cGMP, and that hydrolysis of cGMP by light leads to the photocurrent, then being modified by another messenger, IP3, to be amplified.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗
PubMed1991

ATP-dependent transport for glucuronides in canalicular plasma membrane vesicles.

Using rat liver canalicular plasma membrane vesicles, it has been verified that the transport of p-nitrophenyl glucuronide (NPG) across membranes is an ATP-dependent process; the apparent Km for NPG was 20 microM. S-(2,4-dinitrophenyl)-glutathione (DNP-SG) inhibited NPG uptake dose-dependently, and NPG or testosterone glucuronide did ATP-dependent DNP-SG uptake similarly. These results suggest that transport of glucuronide is mediated by an ATP-dependent glutathione S-conjugate carrier.

Adenosine Triphosphate↗
PubMed1991

Neurofibromatosis type 1 (NF1) gene: implication in neuroectodermal differentiation and genesis of brain tumors.

The gene responsible for neurofibromatosis type 1 (NF1), a common autosomal dominantly inherited disease, has been isolated. A region of NF1 gene product has been demonstrated to share structural and functional similarities with the mammalian GTPase activating protein (GAP) and the yeast IRA proteins. Thus, the NF1 protein is thought to play a role in signal transduction by stimulating the conversion of the Ras protein from a GTP-bound active form to a GDP-bound inactive form. The increased risk of malignant tumors in neuroectodermal tissues of NF1 patients may be caused by disruption of growth and differentiation regulatory functions of the NF1 gene. A second type of the NF1-GAP related domain (NF1-GRD) transcript, which has an extra 21-amino-acid insert in the center of the previously reported first type transcript, has been described. This insert significantly changes the hydrophilicity and secondary structure of the central region of NF1-GRD, therefore, suggesting it also changes its function. Alternative splicing is the most likely mechanism by which these two types of transcripts arise. The NF1-GRD alternative splicing has been shown to be intimately involved in differentiation of neuroectodermal tissues. Aberrant regulation of the alternative splicing may contribute to tumor formation in neuroectodermal tissue.

Amino Acid Sequence↗
PubMed1991

Examination of host defense factors responsible for experimental chronic respiratory tract infection caused by Klebsiella pneumoniae in mice.

We have studied the host defense factors that operate during the course of chronic respiratory tract infection caused by Klebsiella pneumoniae 27 in CBA/J mice. A large number of polymorphonuclear leukocytes (PMNs) rapidly infiltrated the alveolar spaces after infection. Treatment with cyclophosphamide (CY) before infection greatly reduced the infiltration of PMNs and caused an increase in bacterial counts. CY treatment of mice in the chronic phase also caused bacterial proliferation in the lungs. The administration of a high titer immune serum efficiently reduced the bacterial counts in the lungs during the early phase but not during the chronic phase. The proliferation of bacteria induced by CY treatment was not suppressed by the administration of the immune serum in either phase. When the mice were exposed to an aerosol containing Pseudomonas aeruginosa P9 in the chronic phase, the organisms from the secondary infection were eliminated from the lungs in the same manner as in the case of primary infection with P. aeruginosa. Thus, PMNs seem to play an important role in the suppression of bacterial proliferation in the early and chronic phases, and the specific antibody might have a supplementary effect on the defensive action of PMNs in the chronic phase. It is also presumed that the bacteria in the chronic phase of infection are sequestered at sites hardly accessible to PMNs.

Animals↗
PubMed1991

[Three cases of psittacosis].

Case 1 was a 55 year old female whose primary complaint was pyrexia. Anamnesis consisted of a fever at a 39 degrees C level beginning on September 15, 1987 with headache and muscle pain. The patient was examined by a nearby physician. Despite taking medication, there was no break in the fever. The patient was examined and admitted to this institution on September 18. Case 2 was a 32 year old female whose primary complaint was pyrexia and an abnormal sensation in the pharynx. Anamnesis consisted of a fever at a 39 degrees C level beginning on February 13, 1989 and the manifestation of a cough beginning on February 17. Although the fever broke on February 20, as the abnormal sensation in the pharynx persisted, the patient was examined and admitted to this institution on February 21. Case 3 was a 42 year old male whose primary complaint was pyrexia. Anamnesis consisted of a fever of 38 degrees C, cough and a sensation of pressure in the right precordia beginning on November 18, 1989. The patient was examined and admitted to this institution on November 21. Chest X-rays revealed the presence of atypical pneumonia in all three cases. As a significant rise in antibodies to the Chlamydia of parrot fever was observed in the cases at the time of admittance as well as after admittance, treatment was begun by administration of Minocycline.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗