Biomedical subjects

Hitoshi Nakamura

Publications and source records attributed to Hitoshi Nakamura.

At least 19 recordsLinked to original sources

PubMed2006

An endornavirus from a hypovirulent strain of the violet root rot fungus, Helicobasidium mompa.

We determined the complete nucleotide (nt) sequence (16,614 nt) of a large double-stranded (ds) RNA (referred to as L1 dsRNA), previously identified as the hypovirulence factor from strain V670 of the violet root rot fungus, Helicobasidium mompa. The positive-strand of L1 dsRNA contained a long open reading frame (ORF) potentially encoding a protein of 5,373 amino acids (molecular mass 603,080 Da) with conserved motifs characteristic of RNA-dependent RNA polymerase (RdRp) and helicase. The ORF is the longest so far reported in the fungal kingdom. The putative RdRp and helicase were shown to be related to putative RdRps and helicases of members of the genus Endornavirus. As is the case with endornaviruses, the coding (sense) strand of L1 dsRNA contained a discontinuity (nick) at nt position 2,552. A region between the RdRp and helicase domains of the polyprotein also had an amino acid sequence, resembling UDP glycosyltransferases (UGTs) in Oryza sativa endornavirus and Phytophthora endornavirus 1. Regions in the L1 dsRNA-encoded protein presumed to contain putative helicase, UGT and RdRp motifs were present at comparable positions to those in other endornaviruses. L1 dsRNA of H. mompa strain V670 was assigned to the genus Endornavirus, and here, we designate it as H. mompa endornavirus 1-670 (HmEV1-670). This represents the first report of a fungal endornavirus whose complete nucleotide sequence has been determined.

Amino Acid Motifs↗

PubMed2005

Comparison between Rosellinia necatrix isolates from soil and diseased roots in terms of hypovirulence.

The white root rot fungus, Rosellinia necatrix, is a devastating soil-borne pathogen of many plant species. Biocontrol with the hypovirulence factor is promising, but disease symptoms, signs or culture morphology of the pathogen cannot be reliably used as markers for hypovirulence in this fungus. We attempted to obtain hypovirulent isolates from soil rather than from diseased roots, based on the hypothesis that hypovirulent isolates were more likely to persist in soil as saprobes. Sixteen isolates, belonging to eight mycelial compatibility groups (MCGs), were obtained from soil in two active and one abandoned Japanese pear orchards. Comparison of these isolates based on clonality revealed that six MCGs were commonly recovered from both diseased roots and soil and two MCGs exclusively from soil. No MCG was found in more than one orchard. With two exceptions, isolates within the same MCG were similar in virulence, competitive saprophytic ability (CSA) and mycelial growth rate whether or not they carried dsRNA. The two exceptional isolates recovered from soil had multiple dsRNA segments that caused hypovirulence, weakened CSA and restricted mycelial growth on nutrient-rich media. They belonged to different MCGs, each including dsRNA-free isolates. Isolates from soil contained various dsRNAs (44%), including the hypovirulence factor, more frequently than isolates from diseased roots in the same fields (25%), which is much higher than the proportion of isolates with dsRNA from diseased roots (19%) in a total of 424 isolates from Japan examined so far. These results suggest that isolation of R. necatrix from soil is an effective method to obtain isolates with dsRNAs, including the hypovirulence factor.

Ascomycota↗

PubMed2005

Nucleotide sequence of a mitochondrial RNA virus from the plant pathogenic fungus, Helicobasidium mompa Tanaka.

A double-stranded (ds) RNA (2411 bp) from a strain V18 of the violet root rot basidiomycetous fungus, Helicobasidium mompa was sequenced. Using the fungal mitochondrial genetic code in which UGA codes for tryptophan, the positive strand of V18 dsRNA was found to contain a long open-reading frame with the potential to encode a protein of 700 amino acids (molecular mass 79,805 Da), including conserved motifs characteristic of RNA-dependent RNA polymerase (RDRP). This putative RDRP was shown to be related to putative RDRPs of several fungal mitochondrial viruses. It is proposed that V18 dsRNA is assigned to the genus Mitovirus in the family Narnaviridae and designated as H. mompa mitovirus 1-18 (HmMV1-18). Like other mitoviruses, HmMV1-18 RNA can be folded into potentially stable stem-loop structures at both the 5'- and 3'-termini, and both terminal sequences have inverted complementarity with the potential to form panhandle structure. BLAST analysis indicates that the RDRP encoded by HmMV1-18 is more closely related to those encoded by mitochondrial viruses of some ascomycetes than to that of the unassigned RsM2-1A1 dsRNA in the basidiomycetous Rhizoctonia solani. HmMV1-18 is the first member of the genus Mitovirus from basidiomycete fungi.

Amino Acid Sequence↗

PubMed2005

An analysis of thyroid function diagnosis using Bayesian-type and SOM-type neural networks.

Thyroid function diagnosis is an important classification problem, and we made reanalysis of the human thyroid data, which had been analyzed by the multivariate analysis, by the two notable neural networks. One is the self-organizing map approach which clusters the patients and displays visually a characteristic of the distribution according to laboratory tests. We found that self-organizing map (SOM) consists of three well separated clusters corresponding to hyperthyroid, hypothyroid and normal, and more detailed information for patients is obtained from the position in the map. Besides, the missing value SOM which we had introduced to investigate QSAR problem turned out to be also useful in treating such classification problem. We estimated the classification rates of thyroid disease using Bayesian regularized neural network (BRNN) and found that its prediction accuracy is better than multivariate analysis. Automatic relevance determination (ARD) method of BRNN was surely verified to be effective by the direct calculation of classification rates using BRNN without ARD for all possible combinations of laboratory tests.

Bayes Theorem↗

PubMed2004

Dynamics of double-stranded RNA segments in a Helicobasidium mompa clone from a tulip tree plantation.

Eighty-three isolates of the violet root rot fungus, Helicobasidium mompa, were collected in a tulip tree plantation and analyzed for the dynamics of double-stranded (ds) RNA for five years. They were divided into eight mycelial compatibility groups (MCGs). Prevalent MCGs 60 and 68 included 61 and 11 isolates, respectively. Electrophoretic profiles of dsRNA in the first year collection of MCG 60 contained no or a single large dsRNA (more than 10 kb) with or without small dsRNAs (ca. 2.0-2.5 kb). Additional dsRNA fragments, i.e., a middle dsRNA (ca. 8.0 kb) or another type of small dsRNAs, became evident within MCG 60 isolates with time. Northern hybridization revealed the relatedness of all large and middle dsRNA fragments within MCG 60 but small fragments of dsRNA were variable. Large dsRNA fragment differed from that in other MCGs even in the same field. Correlation between specific dsRNA fragments and hypovirulence was not observed. Possible explanations for the accumulation of dsRNA fragments during the growth of disease patch by MCG 60 are discussed in terms of their internal changes such as evolution of novel dsRNA fragments from pre-existing viruses or fungal genomic DNA and horizontal transmissions.

Agriculture↗

PubMed2004

Apollon ubiquitinates SMAC and caspase-9, and has an essential cytoprotection function.

Apollon (also known as BRUCE or BIRC6) is a large protein containing baculoviral-IAP-repeat (BIR) and ubiquitin-conjugating enzyme (UBC) domains at the amino- and carboxy termini, respectively. Apollon inhibits apoptosis, but its molecular and physiological function remains unclear. Here we report that Apollon binds to, ubiquitinates and facilitates proteasomal degradation of SMAC and caspase-9, which both contain IAP-binding motifs. Targeted disruption of Apollon in mice caused embryonic and neonatal lethality. Notably, SMAC induced apoptosis in Apollon-deficient cells, but not in Apollon-expressing cells. Furthermore, the IAP-binding motif of SMAC was required to induce apoptosis in Apollon-deficient cells. These results suggest that Apollon has an essential function in preventing SMAC-induced apoptosis.

Animals↗

PubMed2004

Diversity and vertical transmission of double-stranded RNA elements in root rot pathogens of trees, Helicobasidium mompa and Rosellinia necatrix.

The diversity and vertical transmission of double-stranded (ds) RNA in Helicobasidium mompa and Rosellinia necatrix was examined by electrophoresis and Northern hybridization. These two fungi share the similar niche as root rot pathogens of trees in forests and orchards, and had diverse dsRNAs. The detection frequency of dsRNA in both fungi was different; in H. mompa, 68.4% (132 out of 193 MCGs; mycelial compatibility groups) had dsRNA, whereas 20.9% (53 out of 254 MCGs) in R. necatrix. dsRNA banding patterns and Northern blot analyses revealed the presence of various dsRNA elements in both fungi. Hyphal tip isolation was mostly unsuccessful to remove dsRNA with some exceptions. Sexual reproduction functioned to remove dsRNA in both fungi since dsRNA was not detected from single sexual spore cultures. Possible explanations for the difference in the detection frequency of dsRNA are discussed in terms of the differences in their sexual reproduction and other factors.

Basidiomycota↗

PubMed2004

A comparative study of the violet root rot fungi, Helicobasidium brebissonii and H. mompa, from Japan.

A violet root rot fungus recently found in Japan was identified as Helicobasidium brebissonii. The fungus was compared with another violet root rot fungus, H. mompa, which is distributed throughout Japan, in terms of morphological characteristics of the basidiospores and the conidial state, sequences of rDNA ITS regions, and pathogenicity on carrot, sweet potato and apple rootstock. The two species were clearly discriminated by these features and the taxonomic status of both species is discussed.

Basidiomycota↗

PubMed2004

Effect of mixing method on the mixing degree during the preparation of triturations.

By using lactose colored with erythrocin, we investigated the effects of mixing methods on mixing degree during the preparation of trituration with a mortar and pestle. The extent of powder dilution was set to 4 to 64 fold in the experiments. We compared the results obtained by using two methods: (1) one-step mixing of powders after addition of diluents and (2) gradual mixing of powders after addition of diluents. As diluents, we used crystallized lactose and powdered lactose for the preparation of trituration. In the preparation of 64-fold trituration, an excellent degree of mixing was obtained, with CV values of less than 6.08%, for both preparation methods and for the two kinds of diluents. The mixing of two kinds of powders whose distributions of particle sizes were similar resulted in much better degree of mixing, with CV values of less than 3.0%. However, the concentration of principal agents in 64-fold trituration was reduced by 20% due to the adsorption of dye to the apparatus. Under conditions in which a much higher dilution rate and/or much better degree of dilution was required, it must be necessary to dilute powders with considering their physicality and to determine the concentrations of principal agents after the mixing.

Chemistry, Pharmaceutical↗

PubMed2004

Effect of particle size on mixing degree in dispensation.

By using lactose colored with erythrocin, we examined the effect of particle size on mixing degree during the preparation of triturations with a mortar and pestle. We used powders with different distributions of particle sizes, i.e., powder that passed through 32-mesh but was trapped on a 42-mesh sieve (32/42-mesh powder), powder that passed through a 42-mesh sieve but was trapped on a 60-mesh sieve (42/60-mesh powder), powder that passed through a 60-mesh sieve but was trapped on a 100-mesh sieve (60/100-mesh powder), and powder that passes through a 100-mesh sieve (> 100-mesh powder). The mixing degree of colored powder and non-colored powder whose distribution of particle sizes was the same as that of the colored powder was excellent. The coefficient of variation (CV) value of the mixing degree was 6.08% after 40 rotations when colored powder was mixed with non-colored powder that both passed through a 100-mesh sieve. The CV value of the mixing degree was low in the case of mixing of colored and non-colored powders with different particle size distributions. After mixing, about 50% of 42/60-mesh powder had become smaller particles, whereas the distribution of particle sizes was not influenced by the mixing of 60/100-mesh powder. It was suggested that the mixing degree is affected by distribution of particle sizes. It may be important to determine the mixing degrees for drugs with narrow therapeutic ranges.

Chemical Phenomena↗

PubMed2004

Analysis of information submitted by clinical trial sponsors regarding the safety of investigational drugs.

During performance of clinical trials in medical institutions, information regarding the safety of investigational drugs is submitted by trial sponsors according to guidelines for good clinical practice. In the present study, reports of clinical trials conducted at the University of Tokyo Hospital were examined, focusing on the safety information provided to the Institutional Review Board (IRB). Two hundred two reports (52 protocols) of safety information were submitted to the IRB by clinical trial sponsors between April 2000 and March 2001, of which 185 contained a total of 3021 cases of adverse events. Of those, 194 reports were judged by clinical investigators/physicians not to be associated with any significant problems and the trials were continued. For 157 of those 194 reports, it was considered unnecessary to inform the test subjects of the report contents, including the adverse events. The decision of whether or not the test subjects should be informed of such contents tended to depend on the causal relationship between the adverse events and drug intake, as well as the predictability of the adverse events. For 8 of those 194 reports, the IRB recommended that the clinical investigators/ physicians provide information to the test subjects and/or submit detailed information on the status of these subjects to the IRB. From these results, we suggest that establishment of a system to unify and evaluate drug safety information is necessary to provide safe and efficient clinical trials.

Clinical Trials as Topic↗

PubMed2004

Development and evaluation of pharmaceutical services in the ICU/CCU by medical staffs.

Questionnaires were sent out to the staffs (13 physicians, 52 nurses and 5 medical engineers) of the ICU/CCU at the University of Tokyo Hospital, to evaluate pharmaceutical services by analyzing problems in the services offered. Four components of pharmaceutical services were evaluated: inventory control of drugs, check of drug usage and doses, mixing of injections, and offering drug information. Almost all responses from medical staffs evaluated pharmaceutical services overall as "good". The high response rate (96%) from the nursing staff was attributed to the fact that they were familiar with the pharmacist's role with drug inventory, and mixing injections, when nursing was not available for these tasks. Although 50% of physicians rated the pharmaceutical services of providing drug information as "good", this value was lower than responses on other items of the questionnaires, which suggests some dissatisfaction. The occurrences of drug information obtained by passive offering (121 subjects) was 4 times as common as drug information obtained by active offering (30 subjects). From this finding, and comments on the questionnaires from physicians, it suggests that physicians require more drug information for dosage regimens, and prefer the drug information to be provided more actively. Further, an important comment from physicians and nurses was that the services of pharmacists are not available on all shifts/all days of the week to provide consultation for drug information and mixing of injections. Although having a pharmacist available daily around the clock is desirable and ideal to the medical team, the number of pharmacists under the present system cannot support this. As a solution, we think that it is crucial that pharmacists educate medical staff when they are present to in order to optimize therapy and patient care over time.

Coronary Care Units↗

PubMed2004

Items of concern associated with source document verification of clinical trials for new drugs.

In the present study, we analyzed concerns of the sponsors of clinical trials regarding source document verification (SDV) procedures performed at the University of Tokyo Hospital during April 1999 and March 2001, with special focus on the differences in description between the source document and case report form (CRF). Of 132 SDV procedures (78 protocols, 496 cases), the sponsors had problematic concerns with 348 cases (70.2%) totalling 693 items, which consisted of description inconsistencies between the source documents and the CRF (41.4%), lack of description in the CRF (39.8%), and lack of description in the source documents (8.8%). The most frequently found inconsistencies between the source documents and CRF were concerning items regarding observations, laboratory examinations, and compliance, which were associated with misdescription of clinical data and/or items for evaluation in the CRF. It was also revealed that the frequent lack of description in the CRF was associated with patient history and/or complications, adverse events, and concomitant drugs and/or therapy. In contrast, the frequent lack of description in the source documents was associated with items concerning patient background, observations, and informed consent. Further, we found that submission of a report of deviation from the protocols was required for 4.0% of the claims. These results suggest the necessity of better data management during the practice of clinical trials for the purpose of maintaining the quality of clinical trials.

Clinical Trials Data Monitoring Committees↗

PubMed2004

[A case of tricuspid valve infective endocarditis presenting with multiple nodular shadows in both lungs without known predisposing factors].

A 56-year-old woman was admitted to our hospital with fever, cough, and sputum production. Her chest radiograph and chest computed tomography showed multiple nodules. Laboratory findings revealed leukocytosis and an increased C-reactive protein concentration. Physical examination revealed a systolic murmur. Transesophageal echocardiography demonstrated a 1.5-cm area of vegetation on the tricuspid valve. Blood cultures grew Staphylococcus aureus. Tricuspid valve endocarditis and septic pulmonary embolism were diagnosed. She was treated successfully with intravenous ampicillin/sulbactam. This was a rare case of tricuspid valve infective endocarditis in an adult patient without known predisposing factors.

Ampicillin↗

PubMed2003

Mycelial incompatibility operative in pairings between single basidiospore isolates of Helicobasidium mompa.

Helicobasidium mompa is a clampless basidiomycete and binucleate both in secondary and primary hyphae. Single basidiospore isolates were paired in sibling and non-sibling combinations. We did not observe any alterations in colony morphology, such as tuft formation, but mycelial incompatibility, as indicated by the presence of a dark demarcation line between colonies, occurred in a unifactorial manner. Techniques using DNA molecular markers, such as internal transcribed spacer-restriction fragment-length polymorphism (ITS-RFLP), inter-simple-sequence-repeat polymerase chain reaction (PCR), and universally primed PCR, failed to identify nuclear migration to opposite single basidiospore isolates in all but one of the 92 pairings. These results imply that single basidiospore isolates of H. mompa may be incompetent to mate under laboratory conditions and that a single mycelial incompatibility factor operates in single basidiospore isolates.

Basidiomycota↗

PubMed2003

Brain and heart specific alteration of methamphetamine (MAP) distribution in MAP-sensitized rat.

The repeated administration of methamphetamine (MAP) causes behavioral sensitization in animals. We previously reported that the high accumulation of MAP was observed in the MAP-sensitized animal brain, which suggested that this phenomenon is an important factor in the development or expression of behavioral sensitization. The purpose of the present study is to elucidate the MAP distribution in the MAP-sensitized rat using gas chromatography/mass spectrometry (GC/MS). As a result, the MAP distribution in the heart at 10 min when showing a high accumulation of MAP in the MAP-sensitized rat brain was significantly higher than that of the control rat, whereas no significant differences in the liver, kidney, abdominal muscle, femoral muscle and blood were observed. In the brain and heart, there was no different distribution at 1 min, reflecting only the influx process from blood to brain and heart. On the contrary, there was the significant difference at 10 min, reflecting both the influx and efflux process, suggesting that the efflux process of MAP from brain or heart to blood may be slow due to MAP sensitization. In conclusion, it was clear that the brain and heart specific alteration of the MAP distribution occurred in the MAP sensitization. It was considered that the high accumulation of MAP in the MAP-sensitized rat brain may be related to the expression of behavioral sensitization and that the delayed efflux of MAP in the MAP-sensitized rat heart may be connected with the cardiac toxicity.

Animals↗

PubMed2003

[Documents for clinical trials of new drugs: results of their reviews prior to submissions to IRB].

A prior review process was introduced in the Institutional Review Board (IRB) of the University of Tokyo Hospital to facilitate the evaluation of clinical trial plans for new drugs. This study summarizes the results of prior reviews of 73 protocols that were submitted to the IRB during 1999-2000. A total of 955 items were taken up for discussion at the prior review. Among them, 325 (34.0%) were related to the profile/description of investigational drugs themselves, and 252 (26.4%) were related to the trial plan. Major requests related to investigational drugs and given to applicants after the prior review were on adverse reactions, pharmacodynamics, and pharmacokinetics. Items related to patient selection criteria and usage of concomitant drugs were major requests related to the protocol. In some cases, protocols were amended by applications in accordance with the requests. The study shows that the review of new drug clinical trial plans prior to the evaluation by the IRB and examination from a pharmaceutical viewpoint are meaningful and worthwhile.

Clinical Trials Data Monitoring Committees↗

PubMed2003

[The interchange between hospital pharmacists and pharmacists: evaluation of practical classes "chozaigijutsu-konwakai" from the participants].

We have held practical classes called chozaigijutsu-konwakai(Konwakai) for pharmacists working in drugstores every month since December 1994. Konwakai is composed of lectures and practice. The practice is carried out for pharmacists to obtain a better understanding of prescriptions and compounding them in exercises. In this study, we analyzed the answers to questionnaires distributed at the end of each konwakai to all participants. It was found that the age of participants as well as the length of compounding experience varied markedly, indicating that pharmacists of various generations are interested in konwakai. Regarding the contents of lectures and practice, the answers indicated that the practice was particularly useful, suggesting the importance of exercise for learning techniques in compounding. Since there were many requests for consultations on routine work, frequent communications between pharmacists in the hospital and drugstores appears necessary. In conclusion, regular meetings including practical classes such as konwakai are very important for pharmacists in drugstores that receive prescriptions from hospitals. Further efforts to improve the konwakai should be maid in the future.

Community Pharmacy Services↗