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A Matsuno

Publications and source records attributed to A Matsuno.

At least 19 recordsLinked to original sources
PubMed2001

Complete genomic sequence of the filamentous nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120.

The nucleotide sequence of the entire genome of a filamentous cyanobacterium, Anabaena sp. strain PCC 7120, was determined. The genome of Anabaena consisted of a single chromosome (6,413,771 bp) and six plasmids, designated pCC7120alpha (408,101 bp), pCC7120beta (186,614 bp), pCC7120gamma (101,965 bp), pCC7120delta (55,414 bp), pCC7120epsilon (40,340 bp), and pCC7120zeta (5,584 bp). The chromosome bears 5368 potential protein-encoding genes, four sets of rRNA genes, 48 tRNA genes representing 42 tRNA species, and 4 genes for small structural RNAs. The predicted products of 45% of the potential protein-encoding genes showed sequence similarity to known and predicted proteins of known function, and 27% to translated products of hypothetical genes. The remaining 28% lacked significant similarity to genes for known and predicted proteins in the public DNA databases. More than 60 genes involved in various processes of heterocyst formation and nitrogen fixation were assigned to the chromosome based on their similarity to the reported genes. One hundred and ninety-five genes coding for components of two-component signal transduction systems, nearly 2.5 times as many as those in Synechocystis sp. PCC 6803, were identified on the chromosome. Only 37% of the Anabaena genes showed significant sequence similarity to those of Synechocystis, indicating a high degree of divergence of the gene information between the two cyanobacterial strains.

Anabaena↗
PubMed2001

Cytochemical and molecular biological aspects of the pituitary and pituitary adenomas--cell differentiation and transcription factors.

The anterior pituitary is composed of several cell types, each responsible for the production of specific hormones. Each hormone secreting cells is defined by the activation of its respective hormone genes in a temporally and spatially regulated manner. Recent development in cytochemistry and molecular biology have provided various aspects of human pituitary adenomas, i.e., functional differentiation and classification. The molecular factors that determine hormone production have now been identified as transcription factors. Many novel transcription factors that play a role in anterior pituitary development are implicated. In this review, we focus on the transcriptional factors roles on functional differentiation of the pituitary cells and adenomas and the contribution of cytochemistry and recent development in molecular biological techniques.

Adenoma↗
PubMed2001

Identification of a silent pituitary somatotropic adenoma based on a paradoxic response of growth hormone on a thyrotropin-releasing hormone or gonadotropin-releasing hormone provocation test.

Preoperative endocrinologic identification and surgical removal of a silent somatotropic adenoma among patients with either amenorrhea or galactorrhea, or both, are beneficial for the restoration of menstruation and ovulation. Paradoxic rises of serum growth hormone in either a thyrotropin-releasing hormone or a gonadotropin-releasing hormone provocation test and high serum growth hormone levels were noted in the 3 patients with a silent somatotropic adenoma.

Adenoma↗
PubMed2001

Histopathological analyses of silent pituitary somatotroph adenomas using immunohistochemistry, in situ hybridization and confocal laser scanning microscopic observation.

To characterize the morphological and functional aspects of silent somatotroph adenomas with paradoxical responses of GH in TRH or GnRH provocation tests, which are considered to be a useful strategy for endocrinological identification of silent somatotroph adenomas, we examined three silent somatotroph adenomas histopathologically. The adenomas were investigated by immunohistochemistry, including the highly sensitive catalyzed signal amplification system, the non-radioisotopic in situ hybridization method, and confocal laser scanning microscopy. GH production and GH-immunopositive secretory granules in the adenoma cells were demonstrated histopathologically, and the adenomas were interpreted as being densely granulated somatotroph adenomas. Endocrinological identification of silent somatotroph adenomas in combination with paradoxical responses of GH in TRH or GnRH provocation tests may elucidate the increasing number of silent somatotroph adenomas that have been regarded as mammotroph or clinically inactive adenomas. One should be aware of the differences between the previously reported silent somatotroph adenomas, most of which are sparsely granulated somatotroph adenomas, a somatotroph adenomas with paradoxical and the silent somatotroph adenomas, most of which are sparsely granulated somatotroph adenomas, and the silent somatotroph adenomas with paradoxical responses of GH in TRH or GnRH provocation tests, which are densely granulated somatotroph adenomas.

Adenoma, Chromophobe↗
PubMed2001

Three-dimensional imaging of hormone-secreting cells and their microvessel environment in estrogen-induced prolactinoma of the rat pituitary gland by confocal laser scanning microscopy.

This study focused on the three-dimensional imaging of hormone-secreting cells and their microvascular environment in estrogen-induced prolactinoma of the rat pituitary gland. Adult female Wistar-Imamichi rats were injected with estradiol dipropionate and killed 7 weeks later. Some rats given estrogen for 7 weeks also were injected with bromocriptine before killing. To obtain a detailed three-dimensional image of microvessels, dialyzed fluorescein isothiocyanate (FITC)-conjugated gelatin was injected into the left ventricle of the rat heart. After the perfusion, the pituitary glands were resected and subjected to immunohistochemistry (IHC). To evaluate the effects of estrogen and bromocriptine, IHC was performed with antibodies against prolactin (PRL), adrenocorticotropic hormone (ACTH), and growth hormone (GH). With the combination, microvessels and cells containing PRL, ACTH, and GH could be clearly identified by confocal laser scanning microscopy (CLSM). The PRL cells increased in number and became hypertrophic after prolonged exposure to estrogen. With bromocriptine administration after estrogen treatment, however, PRL cells decreased in number and became atrophic. The current study revealed that estrogen and bromocriptine had significant effects on PRL secretion and the microvascular environment. Therefore, this technique (FITC injection and IHC) with CLSM is suitable for the three-dimensional imaging of hormone-secreting mechanisms under various conditions.

Adrenocorticotropic Hormone↗
PubMed2000

Complete genome structure of the nitrogen-fixing symbiotic bacterium Mesorhizobium loti.

The complete nucleotide sequence of the genome of a symbiotic bacterium Mesorhizobium loti strain MAFF303099 was determined. The genome of M. loti consisted of a single chromosome (7,036,071 bp) and two plasmids, designated as pMLa (351,911 bp) and pMLb (208, 315 bp). The chromosome comprises 6752 potential protein-coding genes, two sets of rRNA genes and 50 tRNA genes representing 47 tRNA species. Fifty-four percent of the potential protein genes showed sequence similarity to genes of known function, 21% to hypothetical genes, and the remaining 25% had no apparent similarity to reported genes. A 611-kb DNA segment, a highly probable candidate of a symbiotic island, was identified, and 30 genes for nitrogen fixation and 24 genes for nodulation were assigned in this region. Codon usage analysis suggested that the symbiotic island as well as the plasmids originated and were transmitted from other genetic systems. The genomes of two plasmids, pMLa and pMLb, contained 320 and 209 potential protein-coding genes, respectively, for a variety of biological functions. These include genes for the ABC-transporter system, phosphate assimilation, two-component system, DNA replication and conjugation, but only one gene for nodulation was identified.

ATP-Binding Cassette Transporters↗
PubMed2000

Sequence and analysis of chromosome 5 of the plant Arabidopsis thaliana.

The genome of the model plant Arabidopsis thaliana has been sequenced by an international collaboration, The Arabidopsis Genome Initiative. Here we report the complete sequence of chromosome 5. This chromosome is 26 megabases long; it is the second largest Arabidopsis chromosome and represents 21% of the sequenced regions of the genome. The sequence of chromosomes 2 and 4 have been reported previously and that of chromosomes 1 and 3, together with an analysis of the complete genome sequence, are reported in this issue. Analysis of the sequence of chromosome 5 yields further insights into centromere structure and the sequence determinants of heterochromatin condensation. The 5,874 genes encoded on chromosome 5 reveal several new functions in plants, and the patterns of gene organization provide insights into the mechanisms and extent of genome evolution in plants.

Animals↗
PubMed2000

Growth hormone-releasing hormone expression in pituitary somatotroph adenomas, studied by immunohistochemistry and in situ hybridization using catalyzed signal amplification system.

Growth hormone-releasing hormone (GHRH) is a well-known hypothalamic hormone that stimulates the synthesis and release of growth hormone (GH) as well as the proliferation of GH-producing cells in the anterior pituitary gland. Recent reports have shown GHRH synthesis in pituitary somatotroph adenomas, but GHRH immunoreactivity has not been shown in previous studies. To confirm the role of locally generated GHRH for the progression of somatotroph adenomas, we investigated the expression of GHRH in 25 pituitary somatotroph adenomas immunohistochemically, through the use of both conventional avidin-biotin-complex (ABC) method and novel catalyzed signal amplified (CSA) system. In addition, we investigated the expression of GHRH mRNA and GHRH receptor mRNA with in situ hybridization (ISH) using the CSA system. The weak immunopositivity of GHRH was observed in only 2 adenomas (8.0%) of 25 somatotroph adenomas using the ABC method. In contrast, 15 adenomas (60.0%) of 25 somatotroph adenomas were immunopositive for GHRH, as shown by CSA system. Very few of nonsomatotroph adenomas were immunopositive for GHRH using the CSA system. The expression of GHRH mRNA was confirmed, using the CSA-ISH system in 13 adenomas (72.2%) of 18 somatotroph adenomas. In 11 adenomas (61.1%) of 18 somatotrophic adenomas, the expression of GHRH receptor mRNA was demonstrated using the CSA-ISH system. This is a first report that clarified histopathologically GHRH production in pituitary somatotrophic adenomas. The demonstration of GHRH and its receptor expression is meaningful in clarifying the autocrine or paracrine regulation of GHRH in GH production and progression of pituitary somatotroph adenomas.

Adenoma↗
PubMed2000

Contributions of immunohistochemistry and in situ hybridization to the functional analysis of pituitary adenomas.

Immunohistochemistry (IHC) and recently in situ hybridization (ISH) have elucidated various aspects of human pituitary adenomas, i.e., functional differentiation and classification, transcription factors and mechanism of hormone production, regulation of hormone secretion, and processing of prohormones. Recently, the use of tyramide (catalyzed signal amplification; TSA or CSA) and RT-PCR has been effective for detection of trivial amount of proteins (peptides) and mRNA, respectively. Immunomolecular histochemistry is expected to further clarify the function and biology of human pituitary adenomas.

Adenoma↗
PubMed2000

Applications of plastic embedding to electron microscopic immunocytochemistry and in situ hybridization in observations of production and secretion of peptide hormones.

Plastic embedding has been used to localize various antigens in conjunction with immunohistochemistry. Peptide hormones have been among the antigens that have been studied extensively. Recent application of water-soluble plastics such as LR White and Lowicryl has extended the ranges of detectable antigens and enabled the observation of antigen-antigen or mRNA-antigen combinations. This review article deals with technical aspects, procedures, and applications in endocrine cells.

Acrylic Resins↗
PubMed2000

Electron microscopic observation of intracellular expression of mRNA and its protein product: technical review on ultrastructural in situ hybridization and its combination with immunohistochemistry.

In situ hybridization (ISH) at the electron microscopic (EM) level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. Three different approaches have been applied by the investigators in this EM-ISH study: preembedding method; non-embedding method using ultrathin frozen sections; and postembedding method. In order to obtain satisfactory morphological preservation and retain the messages, we routinely utilized 6 microns-thick frozen sections fixed in 4% paraformaldehyde for the preembedding method and tissues embedded in LR White resin for the postembedding method. The hybridization signal intensity by the postembedding method was lower, and non-specific signals were relatively frequent, in comparison with the preembedding method. The preembedding method thus appears to be easier and better than the postembedding method from the viewpoint of applicability and preservation of mRNA, although quantitative analysis of the expression of mRNA is rather difficult in the preembedding method. EM-ISH is considered to be an important tool for clarifying the intracellular localization of mRNA and the exact site of specific hormone synthesis on the rough endoplasmic reticulum. The simultaneous visualization of mRNA and encoded protein in the same cells using preembedding EM-ISH and subsequent postembedding immunoreaction with protein A colloidal gold complex is also described. This ultrastructural double-staining method for mRNA and encoded protein can be expected to provide an important clue for elucidating the intracellular correlation of mRNA translation and secretion of translated protein.

Animals↗
PubMed2000

Spontaneous intracranial hypotension associated with bilateral chronic subdural hematomas--case report.

A 34-year-old female presented with spontaneous intracranial hypotension (SIH) manifesting as severe postural headache and meningism. Magnetic resonance (MR) imaging with gadolinium showed diffuse pachymeningeal enhancement. She developed bilateral chronic subdural hematomas 4 weeks after the onset of the symptoms. MR imaging showed descent of the midline structures of the brain. The bilateral chronic subdural hematomas were surgically drained, with no remarkable pressure. Postoperative MR imaging showed complete resolution of the pachymeningeal enhancement and relevation of the midline structures of the brain. SIH is an uncommon and probably unrecognized condition because of the usually benign course. However, this case emphasizes that SIH is not entirely benign. SIH should be considered if there is no identifiable risk for intracranial hemorrhage, particularly in young patients. Neurosurgical intervention for the treatment of the underlying cerebrospinal fluid leak may be required if SIH persists.

Adult↗