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Biomedical subjects

T Nitta

Publications and source records attributed to T Nitta.

At least 19 recordsLinked to original sources

RpoS-dependent regulation of genes expressed at late stationary phase in Escherichia coli.

We have identified 6 Escherichia coli genomic genes, including 4 new genes, responsive to the stationary phase. One of them was regulated positively by RpoS at the stationary phase, and the remaining 5 negatively at a late stationary phase, all of them responding to multiple environmental stresses. Nucleotide sequences as well as such multiple responses revealed that those genes may have more than one overlapping-promoter recognized by different sigma-factors which regulate gene expressions during their cell growth.

Bacterial Proteins

Tissue-specific expression of the gene for a putative plasma membrane H(+)-ATPase in a seagrass.

A cDNA clone corresponding to the gene (ZHA1) for a putative plasma membrane H(+)-ATPase of a seagrass (Zostera marina L.) was isolated and sequenced. Comparison of the amino acid predicted sequence from the nucleotide sequence of ZHA1 with those encoded by known genes for plasma membrane H(+)-ATPases from other plants indicated that ZHA1 is most similar to the gene (PMA4) for a plasma membrane H(+)-ATPase in a tobacco (84.4%). Northern hybridization indicated that ZHA1 was strongly expressed in mature leaves, which are exposed to seawater and have the ability of tolerate salinity; ZHA1 was weakly expressed in immature leaves, which are protected from seawater by tightly enveloping sheaths and are sensitive to salinity. In mature leaves, in situ hybridization revealed that ZHA1 was expressed specifically in epidermal cells, the plasma membranes of which were highly invaginated and morphologically similar to those of typical transfer cells. Therefore, the differentiation of the transfer cell-like structures, accompanied by the high-level expression of ZHA1, in the epidermal cells of mature leaves in particular may be important for the excretion of salt by these cells.

Amino Acid Sequence

Double-stranded RNA in rice: a novel RNA replicon in plants.

The entire sequence of 13952 nucleotides of a plasmid-like, double-stranded RNA (dsRNA) from rice was assembled from more than 50 independent cDNA clones. The 5' non-coding region of the coding (sense) strand spans over 166 nucleotides, followed by one long open reading frame (ORF) of 13716 nucleotides that encodes a large putative polyprotein of 4572 amino acid residues, and by a 70-nucleotide 3' non-coding region. This ORF is apparently the longest reported to date in the plant kingdom. Amino acid sequence comparisons revealed that the large putative polyprotein includes an RNA helicase-like domain and an RNA-dependent RNA polymerase (replicase)-like domain. Comparisons of the amino acid sequences of these two domains and of the entire genetic organization of the rice dsRNA with those found in potyviruses and the CHV1-713 dsRNA of chestnut blight fungus suggest that the rice dsRNA is located evolutionarily between potyviruses and the CHV1-713 dsRNA. This plasmid-like dsRNA in rice seems to constitute a novel RNA replicon in plants.

Amino Acid Sequence

The unusual structure of a novel RNA replicon in rice.

A linear, plasmid-like, double-stranded RNA (dsRNA) was isolated from rice, and its entire sequence of 13,952 nucleotides (nt) was determined. The dsRNA encodes a single, unusually long, open reading frame (13,716 nt, 4,572 amino acid residues), which includes an RNA helicase-like domain and an RNA-dependent RNA polymerase-like domain. A series of Northern hybridization and primer extension experiments revealed that the coding (sense) strand of the dsRNA contains a discontinuity (nick) at a position 1,211 nt (or 1,256 nt) from the 5' end. This discontinuity divides not only the coding strand of dsRNA molecule into a 1,211-nt fragment and a 12,741-nt fragment (or a 1,256-nt fragment and a 12,696-nt fragment) but also divides the long open reading frame into a 5' part of 1,045 nt (348 amino acid residues) and a 3' part of 12,671 nt (4,224 amino acid residues) or a 5' part of 1,090 nt (363 amino acid residues) and a 3' part of 12,626 nt (4,209 amino acid residues). It seems likely that almost all dsRNA molecules in rice plants contain such a discontinuity. This rice dsRNA appears to be a novel and unique RNA replicon.

Base Sequence

Prognostic implications of the extent of surgical resection in patients with intracranial malignant gliomas.

BACKGROUND: The goal of treating patients with malignant gliomas by intracranial surgery has been to remove as much tumor as possible without causing new neurologic deficits. However, it is still debatable whether the degree of surgical resection correlates with survival times of patients with supratentorial gliomas. METHODS: One hundred and one patients with supratentorial malignant gliomas who underwent either a gross total resection, a subtotal resection, and/or a partial resection were examined. A correlation between their length of survival and the degree of surgical resection was determined. RESULTS: The survival rates of patients who underwent total resections were significantly higher than those of patients who underwent subtotal or partial resections (P < 0.01). However, there was no significant difference in the survival rates between the subtotal and partial resection groups. These results also were confirmed by independent variables, such as age, location of the tumors, and histologic subtypes, with the exceptions of temporal gliomas and those younger than 60 years. CONCLUSIONS: The favorable prognosis of patients with malignant gliomas depends upon the total resection of these tumors. These findings should be of help in designing preoperative surgical intervention strategies.

Adolescent

Immunohistochemical characterization of 'small, lymphoid-like cell populations' within germinomas: immunologic and molecular approaches to diagnosis.

Little is known to date about the biological and molecular characteristics of 'small lymphoid cells' within intracranial germinomas. Frozen sections from three germinoma specimens were evaluated immunohistochemically in order to identify phenotypic markers expressed on human lymphoid cells as well as intercellular adhesion molecules. In addition, T-cell receptor (TCR) variable alpha- and beta-chain mRNA expression was analyzed by polymerase chain reaction (PCR). The small cells stained faintly with anti-CD5 in two specimens, but were negative for the T cell specific markers, CD2, CD3, CD7, and CD8. In addition, these cells were weakly positive for CD11b (Mac-1) and CD54 (ICAM-1), but were negative for lymphocyte-specific CD11a (LFA-1) and CD11c (p150,95). No TCR V alpha or V beta gene expression was detected by PCR within these germinoma specimens. The small cells of germinomas with the cytologic appearance of lymphocytes are not derived from T-cells or other lymphocytic lineages.

Adolescent

Discrete subcellular localization of membrane-bound ATPase activity in marine angiosperms and marine algae.

The subcellular distribution of membrane-bound ATPases was compared among terrestrial plants, seagrasses and marine algae by cytochemical techniques. High ATPase activity was detected in the copiously invaginated plsma membrane that was characteristic of transfer cells but not in the tonoplast of epidermal cells in mature leaves of seagrasses. Magnesium- or Ca(2+)-dependent ATPase activity was induced together with the characteristics of transfer cells during the development of leaf tissues able to resist seawater. Northern hybridization revealed the effective induction of the synthesis of mRNA for plasma-membrane H(+)-ATPase during the development of leaves. Such high ATPase activity was not detected in the smooth plasma membranes of marine macro-algae but was found in the membranes of some cytoplasmic vesicles or microvacuoles, providing evidence of the excretion of salts by exocytosis. It appears, therefore, that two essentially different methods for excreting excess salts have developed separately in these two classes of marine plants. The evolution of mechanisms of salt tolerance in the plant kingdom is discussed in terms of the differential subcellular distribution of ATPase activity.

Adenosine Triphosphatases

Profound systemic hypothermia inhibits the release of neurotransmitter amino acids in spinal cord ischemia.

Profound hypothermia induced with cardiopulmonary bypass has a protective effect on spinal cord function during operations on the thoracoabdominal aorta. The mechanism of this protection remains unknown. It has been proposed that the release of excitatory amino acids in the extracellular space plays a causal role in irreversible neuronal damage. We investigated the changes in extracellular neurotransmitter amino acid concentrations with the use of in vivo microdialysis in a swine model of spinal cord ischemia. All animals underwent left thoracotomy and right atrium-femoral artery cardiopulmonary bypass with additional aortic arch perfusion. Lumbar laminectomies were then done and microdialysis probes were inserted stereotactically in the anterior horn of the second and fourth segments of the lumbar spinal cord. The probes were perfused with artificial cerebrospinal fluid at a rate of 2 microliters/min and 15-minute samples were assayed by high-performance liquid chromatography. Group 1 animals (n = 6) underwent aortic clamping distal to the left subclavian artery and proximal to the renal arteries for 60 minutes at normothermia (37 degrees C) and group 2 animals (n = 5) were cooled to a rectal temperature of 20 degrees C before application of aortic clamps, maintained at this level during cardiopulmonary bypass until the aorta was unclamped, and then slowly rewarmed to 37 degrees C. Seven amino acids were studied, including two excitatory neurotransmitters (glutamate and aspartate) and five putative inhibitory neurotransmitters (glycine, gamma-aminobutyric acid, serine, adenosine, and taurine). Glutamate exhibited a threefold increase in extracellular concentration during normothermic ischemia compared with baseline values and remained elevated until 60 minutes after reperfusion. The increase in aspartate concentration was not significant. The extracellular concentrations of glycine and gamma-aminobutyric acid also increased significantly during ischemia and reperfusion. Hypothermia uniformly prevented the release of amino acids in the extracellular space. Glutamate levels remained significantly decreased even after rewarming to normothermia whereas glycine levels returned to baseline values. These results are consistent with a role for excitatory amino acids in the production of ischemic spinal cord injury and suggest that the mechanism of hypothermic protection may be related to decreased release of these amino acids in the ischemic spinal cord.

Analysis of Variance

Human glioma-derived interleukin-10 inhibits antitumor immune responses in vitro.

Intracranial malignant gliomas are sequestered from the immune system yet are associated with broad suppression of host immunocompetence. Immune system dysfunction in patients with gliomas seems to be related to inhibitory mediators produced by glioma cells. We investigated the physiological roles of glioma-derived interleukin (IL)-10 in Class II expression of monocytes, cytokine secretion from lymphocytes, and T cell proliferation in vitro. We could detect the messenger ribonucleic acid transcript of IL-10 in four gliomas by the reverse-transcribed polymerase chain reaction. Glioma-derived IL-10 greatly down-regulated human lymphocyte antigens-DR expression on monocytes. The inhibitory effect of IL-10 on interferon-gamma and tumor necrosis factor-alpha was neutralized by the anti-IL-10 monoclonal antibody; however, the inhibitory effect on IL-2 was not neutralized. Next, supernatants of glioma cells remarkably suppressed T cell proliferation in a dose-dependent fashion; however, this inhibitory effect was not restored by adding anti-IL-10 monoclonal antibodies. The supernatant also inhibited the allocytolytic activity of lymphocytes that were not neutralized by anti-IL-10 monoclonal antibody. IL-10 plays an important role in cytokine synthesis; nevertheless, impaired T cell responsiveness cannot be solely explained by glioma-derived IL-10.

Brain Neoplasms

Aromatase inhibitors: synthesis, biological activity, and structure of 1,2-imidazolylmethylcyclopentanol derivatives.

Two series of 1,2-disubstituted imidazolylmethylcyclopentanol derivatives (5a-d, 10a-d) were prepared by using easily available methyl 2-oxocyclopentanecarboxylate as the starting material. Evaluation of the aromatase inhibitory activities in vitro was performed. Their activities were compared with those of a steroidal aromatase inhibitor, Formestane, and a non-steroidal inhibitor, Fadrozole. Among these compounds, the aromatase inhibitory activities of 5d, 10a, 10b, 10c, 11a, 15a, and 15b were more potent than Formestane. One compound, 1-(4-chlorobenzyl)-cis-2-(1H-imidazol-1-ylmethyl)cyclopentanol+ ++ (10a) was in particular identified as a potent aromatase inhibitor in vitro, exhibiting an IC50 value of 4 x 10(-8)M. The enantiomers of 10a were separated, and their absolute configuration were determined by X-ray crystallography.

Androstenedione

Primary peripheral-postthymic T-cell lymphoma in the central nervous system: immunological and molecular approaches to diagnosis.

Primary intracranial T-cell lymphoma is a very rare clinical entity, and only limited biological studies of this disease have been undertaken. A tumor specimen from a patient with a primary leptomeningeal and perivascular presentation of a T-cell lymphoma was analyzed using cellular and molecular techniques. Frozen sections of the sample were examined by immunohistochemical techniques using monoclonal antibodies to phenotypic marker antigens expressed on human lymphoid cells. Intercellular adhesion molecules expressed on the tumor were studied, as was expression of messenger ribonucleic acid (mRNA) transcripts of the T-cell receptor variable alpha and beta chain genes. The immunophenotypical analysis of lymphoma revealed that the tumor expressed CD2, CD3, CD4, CD5, CD25 and HLA-DR. In addition, all of the adhesion molecules studied (ICAM-1, LFA-3, VLA-1, CD11a, CD11b, and CD11c) were detected on the cell surface. Polymerase chain reaction amplification of mRNA from the tumor demonstrated 10 V alpha and three V beta T-cell receptor subfamilies, indicating that this tumor was a low-grade well-differentiated helper type of peripheral T-cell lymphoma of the central nervous system. In addition, the tumor was derived from multiple T-cell lineages.

Adult

Melanotic neuroectodermal tumor of infancy: a molecular approach to diagnosis. Case report.

A case of melanotic neuroectodermal tumor of infancy arising from the transverse sinus is presented. The tumor was located on the outer surface of the dura and extended extracranially through the occipitomastoid suture. Two cell populations were observed: pigmented melanocyte-like cells and small neuroblast-like cells. Ultrastructural analysis revealed epithelial tumor cells and melanosomes at various stages. Expression of melanotransferrin messenger RNA transcripts within the tumor tissue was observed using a reverse transcriptase-polymerase chain reaction method in addition to immunohistological studies. The positive expression of melanotransferrin confirmed that this melanotic neuroectodermal tumor was derived from neural crest cells.

Base Sequence

[Clinical studies of spermatogenic damage in patients with testicular cancer].

We investigated the spermatogenic function of patients with testicular cancer, and the influences of anti-cancer chemotherapy on testicular function in these patients. Fifty-one patients with testicular cancer were selected for evaluation of their testicular function, including spermatogenesis and endocrinological function, before and after chemotherapy with anti-cancer agents. Before chemotherapy with anti-cancer agents, 22 of 49 patients (44.8%) had a sperm concentration of less than 20 x 10(6)/ml, and 8 patients (16.3%) showed azoospermia. The mean sperm concentration of the patients with testicular cancer was 29.0 x 10(6)/ml before therapeutic chemotherapy with anti-cancer agents, but within 3 months after chemotherapy, it decreased to 3.86 x 10(6)/ml (p < 0.01). Fifteen of 19 patients (73.7%) were revealed to have azoospermia. Damage to spermatogenesis became more severe with the number of chemotherapy treatment. No patients had a detectable sperm count at the completion of 3 or more courses of chemotherapy. But some patients who received 3 courses or more of chemotherapy showed recovered sperm counts after 2 or more years. Thus, a lack of sperm after chemotherapy for cancer did not necessarily indicate inability to recover spermatogenesis over 2 years after chemotherapy. Serum FSH levels of the patients were 5.62 +/- 3.43 mIU/ml before chemotherapy, and 19. 70 +/- 17.06 mIU/ml (p < 0.05) at the time of its completion. Serum FSH levels could reflect damage to spermatogenesis in these cases. Cases in which spermatogenesis did not recover may have higher serum FSH levels than those with recovery of spermatogenesis.

Adolescent

Significance of serum neuron-specific enolase as a predictor of relapse of small cell lung cancer.

We conducted a prospective study to evaluate the significance of serum neuron-specific enolase (NSE) as a predictor of relapse of small cell lung cancer (SCLC). Patients entered into the study were drawn from those who had shown a complete or partial response to first-line chemotherapy with a concurrent decline in the NSE level to less than 10 ng/ml. When the serum NSE level increased to more than 15 ng/ml, the patient was restaged on the basis of clinical, radiological, and bronchoscopic examinations. During the period from August 1988 to December 1990, 57 patients with SCLC were enrolled and followed up until May 1992. Of these patients, 45 had clinical relapses, and 14 (31%) of them showed a clear elevation of the serum NSE level prior to the clinical recognition of relapse. Although one false-positive case was noted, this involved only a transient elevation of the NSE level. In patients who showed increased NSE levels, the relapses occurred in more difficult to detect silent sites such as the adrenal gland, liver, and deep lymph nodes. In addition, the percentage of patients demonstrating high NSE levels who were able to benefit from salvage chemotherapy was higher than for those who did not (RHO < 0.05). Our results indicate that serial NSE measurements are useful for the early prediction of SCLC relapse and should help to facilitate early administration of salvage chemotherapy for affected patients.

Adult

[A 49-year-old man with progressive dysarthria, dysphagia, and left hemiparesis].

We report a 49-year-old man who presented progressive dysarthria, dysphagia, and left hemiparesis. The patient was well until June 28th of 1993 when he noted 'weakness' in his both legs; despite his weakness, he could play golf on that day. In the beginning of July, he noted difficulty in swallowing solid foods. He was admitted to the neurosurgery service of our hospital on July 15th of 1993 and a neurologic consultation was asked on July 17th. Neurologic examination at that time revealed an alert but somewhat childish man who appeared to have some difficulty in paying attention to questions. He was disoriented to time and showed difficulty in recent memory and calculation. Higher cerebral functions were intact. The optic fundi were normal; pupils were isocoric and reacted to light promptly; ocular movements were intact, however, he showed difficulty in convergence. Facial sensation and facial muscles were intact. He had no deafness. He showed slurred speech and difficulty in swallowing solid foods. The remaining cranial nerves were intact. Motor-wise, he was able to walk normally and no weakness or atrophy was noted. Mild ataxia was noted in the finger-to-nose and the heel-to-knee test on the left. Muscle stretch reflexes were normal and symmetric, however, the plantar response was extensor bilaterally. Sensation was intact and no meningeal signs were noted. General routine laboratory findings were unremarkable. CSF was under a normal pressure containing 1 cell/microliter, 68 mg/dl of protein, and 54 mg/dl of glucose. Cranial CT scan showed low density areas involving the pons, midbrain, left thalamus, and the left parietal cortex. In MRI, these areas presented low signal intensity in T1-weighted images and high signal intensity in T2-weighted in images. The brain stem appeared swollen. Gadolinium enhancement was negative. He was given a course of steroid pulse with 1 g/day of DIV methylprednisolone for three days followed by oral steroid. He showed only temporary improvement in swallowing. In the subsequent course, he showed progressive deterioration in dysarthria and dysphagia. A biopsy was performed on the left parietal lobe lesion. After biopsy, he was treated with steroid and glycerol without improvement. A course of chemotherapy with procarbazine, MCNU, and vincristine was given; he did not respond to chemotherapy. His left hemiparesis deteriorated. He developed aspiration pneumonia from dysphagia and expired on October 22, 1993. The patient was discussed in a neurologic CPC, and the chief discussant arrived at the conclusion that the patient had astrocytoma grade III involving the pons, midbrain, thalamus, and the parietal cortex.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain Neoplasms

[A clinicopathological study of 16 cases with optico-hypothalamic glioma].

Although gliomas of the optic nerve pathways, optico-hypothalamic gliomas, have been considered to be benign neoplasms, some recurrent, malignant gliomas especially at the optic chiasm and hypothalamus have also been reported. It is crucial to know the factors that influence the prognosis of these tumor entities. In order to address this question, we analyzed 16 cases of optico-hypothalamic gliomas treated in our institute with emphasis especially upon the age, location of tumor, histological subtype and treatment modality. Eleven patients younger than 20 years and five older than 20 years were included in this study. In two patients the gliomas were accompanied by neurofibromatosis 1. The male to female ratio was 9:7. Anatomical locations of the tumors were categorized from T1 to T4, and visual symptoms were V0 to V4. Patients with tumors located within the optic nerve, chiasm (T1-3) mainly presented visual symptoms, but those with hypothalamus (T4) showed neuroendocrine signs but not visual ones. Twelve out of 16 cases represented isodense mass lesions on plain CT scans, which were homogenously enhanced by contrast media. Among 15 cases verified pathologically, 10 cases were pilocytic astrocytomas, 4 were astrocytomas and one was anaplastic astrocytoma. The survival rate was measured by Kaplan-Meier method and overall 5-year survival rate was 70.5%. Patients younger than 20 years could survive longer than those older than 20 years (87.5% and 40.0% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

[A clinicopathological study of nine cases of midbrain glioma].

The majority of brain stem gliomas tend to occur during childhood and arise in the pons. The prognosis of these typical pontine gliomas is almost invariably bad. In contrast, there exists a group of benign brain stem gliomas, mostly arising from the midbrain and are amenable to surgical resection. They are often low-grade astrocytomas and are associated with better prognosis. We summarized nine cases of intrinsic midbrain gliomas and their clinical behavior was analyzed by radioimagings and histopathological examination. They were classified from CT images according to Stroink et al. and from anatomic staging by Epstein. The result showed that 5 in 9 cases were so called, "focal midbrain gliomas". That is to say, the tumor arose from the tectal plate or the tegmentum of the mesencephalon and expanded dorsally, but did not invade the surrounding neural tissues. Three focal midbrain gliomas in childhood were well demarcated and surgically resectable. Histologically, tumors were astrocytomas and were associated with favorable prognosis. However, two focal midbrain gliomas in adulthood were anaplastic astrocytoma and the prognosis was poor, even though they appeared similar shown on radioimaging study. The overall survival rate of patients with midbrain glioma was longer than that of patients with glioma in the cerebral hemisphere. From these results, it was concluded that a specific group of intrinsic, focal midbrain gliomas can be classified into pediatric benign gliomas and adolescent malignant ones. A further number of cases should be studied to clarify this hypothesis.

Adolescent