Biomedical subjects

M Hatta

Publications and source records attributed to M Hatta.

At least 19 recordsLinked to original sources

PubMed2005

Thypedin, the multi copy precursor for the hydra peptide pedin, is a beta-thymosin repeat-like domain containing protein.

Pedin, a peptide of 13 amino acids, stimulates foot formation in hydra, one of the simplest metazoan animals. Here, we show that the corresponding transcripts are 3.8 kb in size encoding a precursor protein with a size of about 110 kDa, which contains 13 copies of the peptide. Interestingly, the deduced amino acid sequence of the precursor comprises 27 copies of a beta-thymosin-like repeat domain. Hence, we named the precursor protein thypedin. Pedin transcripts are present along the body axis of the animal with slightly higher abundance in the foot to bud region and in the head. Pedin is expressed mainly in epithelial cells of the ectoderm and endoderm. During budding it is present in the evaginating bud. The early appearance of transcripts during phases of cell-fate specification like budding indicates that pedin may be involved in differentiation processes in hydra. This is confirmed by the fact that pedin stimulates bud outgrowth. Thymosin-repeat containing proteins are well known for their regulatory influence on actin polymerisation. Here we show the first indirect evidence that thypedin may be able to interact with actin as well. Since actin polymerisation and depolymerisation processes are known to take place during morphogenetic processes, these findings may hint at new aspects of the function of pedin and its precursor in pattern formation in hydra.

Actins↗

PubMed2005

Does incineration turn infectious waste aseptic?

Incineration of infectious waste is considered to be biologically safe. We performed basic experiments to confirm that bacillus spores are killed by incineration in a muffle furnace. Biological samples containing 10(6) spores of Bacillus stearothermophilus were placed in stainless steel Petri dishes and then into hot furnaces. The furnace temperature and duration of incineration were 300 degrees C for 15 min, 300 degrees C for 30 min, 500 degrees C for 15 min, 500 degrees C for 30 min and 1100 degrees C for 3 min. We confirmed that all spores of B. stearothermophilus were killed at each of these settings. The effect of incineration seems to be equivalent to that of sterilization, based on the satisfactory sterilization assurance level of 10(-6).

Geobacillus stearothermophilus↗

PubMed2005

Evaluation of a fully automated system (RAISUS) for rapid identification and antimicrobial susceptibility testing of Staphylococci.

RAISUS is a system for rapid bacterial identification and antimicrobial susceptibility testing. RAISUS and VITEK showed 97.8% and 75.9% agreement in identification of 45 Staphylococcus aureus strains and 58 coagulase-negative staphylococci (CoNS), respectively, and RAISUS and CLSI (formerly NCCLS) methods showed 87.2% and 87.9% agreement in the MICs for S. aureus and CoNS, respectively. RAISUS provided these data within 3.75 h, suggesting its utility for clinical bacteriological laboratories.

Anti-Bacterial Agents↗

PubMed2003

Identification of a vasopressin-like immunoreactive substance in hydra.

Vasopressin (VP)-like immunoreactivity has long been known in the hydra nervous system, but has not yet been structurally identified. In this study, using HPLC fractionation and an immunological assay, we have purified two peptides, FPQSFLPRGamide and SFLPRGamide, from Hydra magnipapillata. Both the peptides shared the same C-terminal structure, -PRGamide, with Arg-VP. The nonapeptide proved to be Hym-355, a peptide that stimulates neuronal differentiation in hydra. Detailed evaluation by competitive enzyme-linked immunosorbent assay (ELISA) and double immunostaining using anti-VP and anti-Hym-355 antibodies enabled us to conclude that the two peptides account for a major part of the VP-like immunoreactivity in hydra nerve cells.

Amino Acid Sequence↗

PubMed2003

Reverse genetics for the control of avian influenza.

Avian influenza viruses are major contributors to viral disease in poultry as well as humans. Outbreaks of high-pathogenicity avian influenza viruses cause high mortality in poultry, resulting in significant economic losses. The potential of avian influenza viruses to reassort with human stains resulted in global pandemics in 1957 and 1968, while the introduction of an entirely avian virus into humans claimed several lives in Hong Kong in 1997. Despite considerable research, the mechanisms that determine the pathogenic potential of a virus or its ability to cross the species barrier are poorly understood. Reverse genetics methods, i.e., methods that allow the generation of an influenza virus entirely from cloned cDNAs, have provided us with one means to address these issues. In addition, reverse genetics is an excellent tool for vaccine production and development. This technology should increase our preparedness for future influenza virus outbreaks.

Animals↗

PubMed2001

Reverse genetics approach towards understanding pathogenesis of H5N1 Hong Kong influenza A virus infection.

In 1990, Palese and colleagues established a method (reverse genetics) that allowed one to generate influenza virus containing a gene segment derived from cloned cDNA. Although this method contributed tremendously to our understanding of influenza pathogenesis, the requirement of helper viruses limited its use in many experimental settings. Recently, we and others established systems for the generation of influenza viruses entirely from cloned cDNAs. These systems require only DNA cloning and transfection techniques, and can therefore be easily implemented by laboratories working in the fields of molecular biology and virology. Thus, for the first time, a system is now available that allows highly efficient generation of influenza virus without technical limitations. Using this technology, we generated the same strain of H5N1 influenza viruses that caused an outbreak in Hong Kong in 1997, killing six people.

Animals↗

PubMed2001

Molecular basis for high virulence of Hong Kong H5N1 influenza A viruses.

In 1997, an H5N1 influenza A virus was transmitted from birds to humans in Hong Kong, killing 6 of the 18 people infected. When mice were infected with the human isolates, two virulence groups became apparent. Using reverse genetics, we showed that a mutation at position 627 in the PB2 protein influenced the outcome of infection in mice. Moreover, high cleavability of the hemagglutinin glycoprotein was an essential requirement for lethal infection.

Amino Acid Sequence↗

PubMed2001

PODs in the nuclear spot: enigmas in the magician's pot.

The promyelocytic leukemia (PML) nuclear body, also known as the PML oncogenic domain (POD), is implicated in the pathophysiology of PML. These nuclear subcompartments are dynamic structures. The PML protein, which undergoes a fusion event in patients with promyelocytic leukemia, is normally found in PODs. The PML protein may be a major regulator of the constituents of PODs, controlling POD organization and function. Hatta and Fukamizu describe the functions of PML and discuss how the POD structure and organization may be regulated and affect apoptosis, gene expression, and cellular transformation.

Animals↗

PubMed2001

Enhancement of foot formation in Hydra by a novel epitheliopeptide, Hym-323.

During the course of a systematic screening of peptide signaling molecules in Hydra magnipapillata, a novel peptide, Hym-323, which enhances foot regeneration was identified. The peptide is 16 amino acids long, and is encoded in the precursor protein as a single copy. Northern blot analysis, in situ hybridization analysis and immunohistochemistry showed that it was expressed in both ectodermal and endodermal epithelial cells throughout the body, except for the basal disk and the head region. The peptide enhanced foot regeneration by acting on epithelial cells. Lateral transplantation experiments indicated that the foot activation potential was increased in the peptide-treated tissue. These results suggest that Hym-323 is a peptide involved in a foot-patterning process in Hydra.

Amino Acid Sequence↗

PubMed2000

Regulation of Lef-mediated transcription and p53-dependent pathway by associating beta-catenin with CBP/p300.

CBP and its homologue p300 play significant roles in cell differentiation, cell cycle, and anti-oncogenesis. We demonstrated that beta-catenin, recently known as a potent oncogene, and CBP/p300 are associated through its CH3 region, which is a primary target of adenoviral oncoprotein E1A and various nuclear proteins, such as p53, cyclin E, and AP-1, and both are colocalized in the nuclear bodies. CBP/p300 potentiated Lef-mediated transactivation of beta-catenin, and E1A, a potent inhibitor of CBP/p300, repressed its transactivation. Furthermore, overexpression of stable beta-catenin mutant competitively suppressed the p53-dependent pathway. These may be a key mechanism of beta-catenin involved in oncogenic events underlying disruption of tumor suppressor function through CBP/p300.

Apoptosis↗

PubMed2000

Precursor genes of future pandemic influenza viruses are perpetuated in ducks nesting in Siberia.

Influenza A viruses of different subtypes were isolated from fecal samples of ducks in their nesting areas in Siberia in summer from 1996 to 1998. Phylogenetic analysis of the NP genes of the isolates in Siberia and those in Hokkaido, Japan on their flyway of migration from Siberia to the south in autumn revealed that they belong to the Eurasian lineage of avian influenza viruses. It is noted that the genes of the isolates in Siberia are closely related to those of H5N1 influenza virus strains isolated from chickens and humans in Hong Kong in 1997 as well as to those of isolates from domestic birds in southern China. The results indicate that influenza viruses perpetuated in ducks nesting in Siberia should have contributed genes in the emergence of the H5N1 virus in Hong Kong. Vaccine prepared from avirulent A/duck/Hokkaido/4/96 (H5N3) influenza virus was potent enough to protect mice from challenge with lethal dose of the pathogenic H5N1 virus [19]. Intensive surveillance study of aquatic birds especially in Siberia is, therefore, stressed to provide information on the future pandemic influenza virus strains and for vaccine preparation.

Animals↗

PubMed2000

Epitope mapping of the influenza A virus RNA polymerase PA using monoclonal antibodies.

To obtain reagents to functionally map the PA protein, we produced monoclonal antibodies specific to this protein. Twenty-two monoclonal antibodies reacting with PA protein in ELISA were divided into 10 groups on the basis of competitive binding patterns to this protein. Of these, seventeen monoclonal antibodies bound to PA polypeptide spanning amino acids 101-400 and three bound to that of amino acids 518-600, while the other two did not react with any PA polypeptides tested with the exception of full-length PA. Among these monoclonal antibodies, only five reacted with PA in A/PR/8/34 virus-infected cells in indirect immunofluorescence assay. Thus, we obtained monoclonal antibodies that recognize at least 10 distinct regions of the PA molecule. These monoclonal antibodies should be useful in dissecting functions of the PA protein.

Animals↗

PubMed2000

Mapping of functional domains on the influenza A virus RNA polymerase PB2 molecule using monoclonal antibodies.

Monoclonal antibodies against the PB2 of A/Puerto Rico/8/34 (A/PR/ 8/34) (H1N1) were prepared in order to define the functional domains of the RNA polymerase of influenza virus. The fifteen monoclonal antibodies that were generated were divided into 4 groups on the basis of ELISA binding to PB2 or its peptide fragments. Six Group I antibodies that bound to the PB2 N-terminal region (amino acids 1-104) did not inhibit transcription by the viral ribonucleoprotein complex. A single Group II antibody recognizing the region of amino acids 206-259 inhibited ApG-primed transcription. Groups III and IV antibodies bound to the C-terminal region of amino acids 660-759. Of these, Group III antibodies inhibited transcription. The present results identify multiple monoclonal antibody binding domains in PB2, two of which, when bound by antibodies, negatively affect viral RNA transcription.

Amino Acid Sequence↗

PubMed2000

Cell type-dependent transactivation or repression of mesoderm-restricted basic helix-loop-helix protein, POD-1/Capsulin.

A family of basic-helix-loop-helix (bHLH) nuclear factors play important roles in controlling cell growth and differentiation as critical regulatory components in transcription. Here we describe molecular characterization of mesoderm-specific bHLH protein, POD-1/Capsulin. Transactivation property of POD-1/Capsulin was analyzed by the Gal4 fusion system in six mammalian cell lines. The results indicated that an activation property was shown in HT1080 and HeLa cells, but a repression activity in HepG2 cells. Mapping analysis for the transactivation and repression activities revealed that the C-terminal domain of POD-1/Capsulin is essential for the transactivation and both the N-terminal and C-terminal domains are contributed to the repression activities. Furthermore, in order to identify possible interactants of the POD-1/Capsulin, we performed yeast two-hybrid screen in a human kidney cDNA library, and identified a class A bHLH protein, ITF-2 as potential heterodimeric partner of the bHLH protein.

3T3 Cells↗

PubMed2000

Retrobulbar optic neuritis and rhegmatogenous retinal detachment in a fourteen-year-old girl with retinitis pigmentosa sine pigmento.

A 14-year-old girl complained of a sudden decrease in right visual acuity. The patient had night blindness, a mottled retina but no pigments, extinguished scotopic electroretinographic response, central scotoma in the right eye and rhegmatogenous retinal detachment. She had initially received laser photocoagulation around the retinal tear and then corticosteroid therapy, cryoretinopexy and segmental buckling. Her right visual acuity increased to 1.0. The association of retinitis pigmentosa sine pigmento, retrobulbar optic neuritis and rhegmatogenous retinal detachment, as demonstrated in our patient, may be uncommon.

Adolescent↗

PubMed2000

A novel neuropeptide, Hym-355, positively regulates neuron differentiation in Hydra.

During the course of a systematic screening of peptide signaling molecules in Hydra a novel peptide, Hym-355 (FPQSFLPRG-NH(2)), was identified. A cDNA encoding the peptide was isolated and characterized. Using both in situ hybridization and immunohistochemistry, Hym-355 was shown to be expressed in neurons and hence is a neuropeptide. The peptide was shown to specifically enhance neuron differentiation throughout the animal by inducing interstitial cells to enter the neuron pathway. Further, co-treatment with a PW peptide, which inhibits neuron differentiation, nullified the effects of both peptides, suggesting that they act in an antagonistic manner. This effect is discussed in terms of a feedback mechanism for maintaining the steady state neuron population in Hydra.

Amino Acid Sequence↗

PubMed2000

Telemedicine system for home automated peritoneal dialysis.

We have developed a new telemedicine system to monitor elderly and handicapped patients that use an automated peritoneal dialysis (APD) system to perform continuous ambulatory peritoneal dialysis (CAPD) at home. The system has two parts: (1) a data collection and transport system, and (2) an interview system ("View Send" system). The former is assembled from the APD cycler, an automated blood-pressure recorder, and a scale. The latter is a combination of a digital camera, television, and set-top box (a kind of computer). The APD system contains recording and data transport junctions, a monitoring device, and a data tabulation function. All data collected by the APD system are sent directly in real time to the physician's office. Patients can easily use this telemedicine system to contact the medical staff at the Saitama Medical School CAPD center and to consult concerning their condition. Furthermore, the staff can directly change the CAPD schedule (dose and duration). Seven patients, including some who are older than 90 years or who are handicapped, have been using this telemedicine system for between 1 and 6 months (average: 3 months). From our recent experience, our tentative conclusions are that (1) elderly and handicapped patients benefit from this system by being able to maintain CAPD without major problems and accidents; (2) other problems are mainly due to simple mistakes such as accidentally pushing the on and off switches; (3) quality of life is improved for the patients.

Aged↗

PubMed2000

Introduction of a rapid dipstick assay for the detection of Leptospira-specific immunoglobulin m antibodies in the laboratory diagnosis of leptospirosis in a hospital in Makassar, Indonesia.

An easy, rapid and robust dipstick assay for detection of leptospira-specific immunoglobulin M (IgM) antibodies was evaluated on 403 patients admitted for hospitalization because of fever. The clinical symptoms and signs of 35 patients were consistent with leptospirosis. The final diagnosis for the remaining patients was as follows: 136 with typhoid fever, 82 with hepatitis, 74 with malaria, 48 with infections of the respiratory tract, and 20 with fever of unknown origin. The clinical diagnosis of leptospirosis was confirmed for 24 (68.6%) patients by the combined results of the microscopic agglutination test (MAT), the reference test for leptospirosis, and of IgM ELISA, a standard laboratory test for the serodiagnosis of leptospirosis. In addition, serum specimens from 8 (2.2%) patients with a final clinical diagnosis other than leptospirosis were found to be positive in MAT and/or IgM ELISA. Compared with the results of MAT and IgM ELISA a sensitivity of 91.6% and specificity of 93.6% was calculated for the dipstick assay. Most of the serum samples from the laboratory confirmed patients gave a moderate to strong staining intensity of the antigen band of the dipstick and were easy to read. The results demonstrate that the dipstick assay is convenient to use and allows the rapid and accurate confirmation of patients with clinical suspicion of leptospirosis in areas where the disease is endemic.

Antibodies, Bacterial↗