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Biomedical subjects

M Takenaka

Publications and source records attributed to M Takenaka.

At least 37 records · Page 2Linked to original sources
PubMed2000

Pheromonal and kairomonal activities can be separated: synthesis and bioactivity studies of pine bast scale sex pheromones and their analogues.

New syntheses were achieved to secure matsuone (1), the pheromone of the pine scale Matsucoccus matsumurae, that of M. feytaudi (2), and that of M. josephi (3). Five analogues (4-8) of 1, 2, and 3 were synthesized and their bioactivities studied. The pheromone analogue 7 showed relatively strong pheromonal activity toward M. josephi, while it was inactive as a kairomone toward the predator Elatophilus hebraicus. Similarly, analogue 8 acted as a pheromone for M. feytaudi, but it did not attract any of its local predators. The M. feytaudi pheromone 2 exhibited strong kairomonal activity toward E. hebraicus, but was not active as a pheromone mimic to attract M. josephi.

Animals↗
PubMed2000

Comparison of expressed sequence tags from male and female sexual organs of Marchantia polymorpha.

A total of 935 expressed sequence tags (ESTs) from male immature sexual organ were determined, of which 600 ESTs were assembled into 110 non-redundant groups, resulting in 445 unique EST sequences. Of these, 244 sequences shared significant similarities to known nucleotide or amino acid sequences in other organisms. The remaining 201 unique sequences showed no significant matches and thus are likely to be novel transcripts. ESTs from male and female immature sexual organs of a liverwort, Marchantia polymorpha, were compared to characterize gene expression patterns during sex differentiation. Ninety-nine male ESTs turned out to be common genes found also in the female library. Interestingly, one of the ESTs found only in male shows a significant similarity to the transformer-2 gene involved in sex determination in Drosophila. In female, several unique lectin ESTs were found that are not present in the male library.

Amino Acid Sequence↗
PubMed2000

Effects of cotinine on sperm motility, membrane function, and fertilizing capacity in vitro.

We evaluated the effect of cotinine on sperm fertilizing capacity in vitro. Human spermatozoa were washed and re-suspended in medium containing albumin and various concentrations of cotinine (0, 100, 200, 400, or 800 ng/ml). After an 8-h incubation period, sperm motility, hypoosmotic swelling test (HOST) outcome, and the percentage of hyperactivated spermatozoa were assayed. Aliquots of spermatozoa were then processed for the zona-free hamster oocyte sperm penetration assay (SPA) or hamster ooplasmic injections. Spermatozoa exposed to concentrations of cotinine equal to 400 or 800 ng/ml demonstrated significantly smaller outcomes for all of the above with the exception of after hamster ooplasmic injections, where high cotinine concentrations did not affect sperm viability or sperm capacity to undergo decondensation and activate hamster oocytes. It appears that cotinine concentrations of 400 or 800 ng/ml exert a detrimental effect on sperm motility, membrane function, and the ability to undergo capacitation. In addition, the current findings suggest that smokers with a high seminal plasma cotinine concentration who participate in assisted reproduction programs may be treated with intracytoplasmic sperm injections (ICSI) rather than conventional in vitro fertilization (IVF) trials.

Animals↗
PubMed2000

Direct transformation and plant regeneration of the haploid liverwort Marchantia polymorpha L.

Thalli of the haploid liverwort Marchantial polymorpha were successfully used for direct particle bombardment with plasmid pMT, which carries a hygromycin phosphotransferase gene (hpt) controlled by the CaMV 35S promoter and the NOS polyadenylation region. Hygromycin-resistant cell masses arose from the thallus surface and developed directly into hygromycin-resistant thalli. Southern blot analyses indicated that these thalli carried at least 1-4 copies of the hpt gene, which were stably transmitted to their asexual thallus progenies via gemma propagation for three generations. This transformation and direct plant regeneration protocol is expected to be a valuable tool for the molecular analysis of this lower land plant.

Anti-Bacterial Agents↗
PubMed2000

Construction of male and female PAC genomic libraries suitable for identification of Y-chromosome-specific clones from the liverwort, Marchantia polymorpha.

Unlike higher plants, the dioecious liverwort, Marchantia polymorpha, has uniquely small sex chromosomes, with X chromosomes present only in female gametophytes and Y chromosomes only in male gametophytes. We have constructed respective genomic libraries for male and female plantlets using a P1-derived artificial chromosome (pCYPAC2). With an average insert size of approximately 90 kb, each PAC library is estimated to cover the entire genome with a probability of more than 99.9%. Male-specific PAC clones were screened for by differential hybridization using male and female genomic DNAs as separate probes. Seventy male-specific PAC clones were identified. The male specificity of one of the clones, pMM4G7, was verified by Southern hybridization and PCR analysis. This clone was indeed located on the Y chromosome as verified by fluorescence in situ hybridization (FISH). This result shows that the Y chromosome contains unique sequences that are not present either on the X chromosome or any of the autosomes. Thus, the respective male and female libraries for M. polymorpha offer an opportunity to identify key genes involved in the process of sex differentiation and this unique system of sex determination.

Base Sequence↗
PubMed2000

Gene expression profiles of the collecting duct in the mouse renal inner medulla.

UNLABELLED: Gene expression profiles of the collecting duct in the mouse renal inner medulla. BACKGROUND: Gene expression profiles, constructed from 1000 to 2000 cloned cDNA sequences, depict their relative abundance of expression in a tissue. Establishing such a profile for mouse inner renal medullary collecting ducts (IMCDs), we compared expression patterns with those in other tissues including proximal tubule. METHODS: A nonbiased 3'-end cDNA library was prepared from microdissected mouse IMCDs. Single-pass sequencing of 2000 randomly selected cDNA clones collected short sequences (approximate length, 250 bp) following poly (A), called gene signatures (GS). Identical sequences were considered a single GS. GS occurrence was quantitated to yield a list of expressed genes indicating their abundance. RESULTS: Among 2000 clones, 1613 types of transcripts were found in IMCDs; 155 were identical or homologous to reported genes. The gene most expressed in IMCDs was alphaB-crystallin, a small stress (heat-shock) protein that is also a major structural protein in the ocular lens. According to Northern analysis, renal expression of this mRNA was induced by dehydration, presumably via tissue hypertonicity. However, expression did not change with acute NaCl loading. Also, a new member of the glutathione-S-transferase family was identified by comparing the IMCD expression profile with those of other tissues. CONCLUSION: With our database of genes expressed in mouse IMCDs, we are devising an IMCD-specific microarray to study gene-expression responses to various physiologic alterations.

Amino Acid Sequence↗
PubMed2000

Quantitation of mRNA expression in glomeruli using laser-manipulated microdissection and laser pressure catapulting.

BACKGROUND: Laser-manipulated microdissection (LMM) is a method to cut out a single cell or limited tiny region from a specimen under microscopic observation by a laser beam. Laser pressure catapulting (LPC) is a method to push up and collect samples that were microdissected using a strong laser. METHODS: To induce experimental glomerulonephritis, anti-Thy1.1 monoclonal antibody (OX-7) was injected intravenously into rats. Control and disease model kidneys were obtained. Six-micrometer thick cryostat sections were mounted onto a 1.35 microm thin polyethylene membrane. Ten glomeruli were collected from 6 microm frozen sections of rat kidney by LMM and LPC. Isolated glomeruli were used to quantitate the expression of mRNA by real-time polymerase chain reaction (PCR). RESULTS: Transforming growth factor-beta1 (TGF-beta1) mRNA was not detected in glomeruli isolated by the LMM and the LPC methods on day 0, although G3PDH mRNA was measurable in the same samples. On day 7 after the treatment with OX-7, the ratio of TGF-beta1/G3PDH mRNA was 1.89 +/- 0.96 (N = 6). CONCLUSIONS: We established methods to isolate glomeruli from standard histochemical specimens by LMM and LPC, and to quantify mRNA expression in the targeted glomeruli using real-time PCR. We confirmed the up-regulation of TGF-beta1 mRNA expression in isolated glomeruli from frozen sections of the anti-Thy1.1 glomerulonephritis model.

Animals↗
PubMed2000

Intrathecal dexmedetomidine attenuates hypercapnic but not hypoxic cerebral vasodilation in anesthetized rabbits.

BACKGROUND: Systemic dexmedetomidine (DXM) attenuates the cerebral vasodilation induced by hypercapnia and decreases the cerebral blood flow response to hypoxia. We determined whether lumbar intrathecal DXM affected the cerebrovascular reactivity to hypercapnia and hypoxia. METHODS: Rabbits (n = 55) anesthetized with pentobarbital were prepared for measurement of pial vessel diameters using a closed cranial window preparation. The first study evaluated the response to hypercapnia after intrathecal administration of DXM (2 microg/kg; n = 7) or normal saline (n = 8). The second evaluated the response to hypercapnia after intrathecal DXM in the presence of yohimbine (20 microg/kg followed by DXM 2 microg/kg; n = 7). The third evaluated the response to mild or moderate hypoxia after intrathecal DXM (2 microg/kg; n = 7) or normal saline (n = 7). The hypercapnic responses were also examined in the presence of systemic DXM (2, 10 microg/kg; n = 6), topical DXM (10-8 m, 10-6 m; n = 6) and of intrathecal clonidine (2 microg/kg; n = 7). RESULTS: The pial arteriolar dilator response to hypercapnia was significantly attenuated after intrathecal administration of DXM. Pretreatment with yohimbine completely blocked the decreased reactivity to hypercapnia. Intrathecal clonidine, although less than DXM, also attenuate the hypercapnic response. Intrathecal DXM did not affect the vasodilation of pial arterioles induced by mild or moderate hypoxia. The systemic DXM 10 microg/kg and topical DXM 10-6 m, but not systemic 2 microg/kg and topical 10-8 m, attenuated hypercapnic vasodilation of pial arterioles. CONCLUSIONS: The presence of alpha2-adrenoceptor agonist administered intrathecally into the lumbar spinal region attenuates hypercapnic but not hypoxic cerebral vasodilation, probably via a stimulation of central alpha2-adrenergic receptors of the central nervous system.

Adjuvants, Anesthesia↗
PubMed2000

Stability and bioavailability of antioxidants in garland (Chrysanthemum coronarium L.).

The stability and bioavailability of the major antioxidants in garland (Chrysanthemum coronarium L.), chlorogenic acid, 3,5-dicaffeoylquinic acid and 4-succinyl-3,5-dicaffeoylquinic acid, were investigated together with caffeic acid. These compounds were stable in artificial digestive juice, but more than 90% of them disappeared from plasma within 30 min after intravenous injection into rats. When they were orally administered, only caffeic acid could be detected.

Administration, Oral↗
PubMed1999

Bryophyte 5S rDNA was inserted into 45S rDNA repeat units after the divergence from higher land plants.

The 5S ribosomal RNA genes (5S rDNA) are located independently from the 45S rDNA repeats containing 18S, 5.8S and 26S ribosomal RNA genes in higher eukaryotes. Southern blot and fluorescence in situ hybridization analyses demonstrated that the 5S rDNAs are encoded in the 45S rDNA repeat unit of a liverwort, Marchantia polymorpha, in contrast to higher plants. Sequencing analyses revealed that a single-repeat unit of the M. polymorpha nuclear rDNA, which is 16,103 bp in length, contained a 5S rDNA downstream of 18S, 5.8S and 26S rDNA. To our knowledge, this is the first report on co-localization of the 5S and 45S rDNAs in the rDNA repeat of land plants. Furthermore, we detected a 5S rDNA in the rDNA repeat of a moss, Funaria hygrometrica, by a homology search in a database. These findings suggest that there has been structural re-organization of the rDNAs after divergence of the bryophytes from the other plant species in the course of evolution.

Blotting, Southern↗
PubMed1999

Two mRNA species encoding calcium-dependent protein kinases are differentially expressed in sexual organs of Marchantia polymorpha through alternative splicing.

In plants, calcium-dependent calmodulin-independent protein kinases (CDPKs) are the predominant calcium-regulated protein kinases and their genes are encoded by a multigene family. A CDPK gene was cloned from a liverwort, Marchantia polymorpha, which showed a high level of sequence similarities to other higher plant CDPK genes. The liverwort CDPK gene consisted of 9 exons and 8 introns. The 6th and 7th exons (Exon 6A and Exon 6B) were almost identical except for 4-amino acid substitutions, both of which coded for EF-hands in the calcium-binding domain. RT-PCR analysis revealed that two species of mature mRNA containing either Exon 6A or Exon 6B were generated from a single CDPK gene by mutually exclusive alternative splicing. Both histidine-tagged fusion proteins derived from cDNAs containing either Exon 6A or Exon 6B exhibited calcium-dependent protein kinase activity in vitro. Preferential accumulation of the mature mRNA with Exon 6A detected in male sexual organ implies possible sexual control of the ratio between the two CDPK isozymes through alternative splicing. Functions and evolution of CDPKs are discussed based on the structure and expression of the liverwort CDPK gene.

Alternative Splicing↗
PubMed1999

Clinical evaluation of repeat apheresis donors in Japan.

BACKGROUND AND OBJECTIVES: To ascertain the safety of repeat apheresis donation, hematological and biochemical tests were performed on 511 donors with a donation rate of over 6 times per year for a period of 12-19 months. MATERIALS AND METHODS: Repeat donors who had apheresis more than 6 times in the previous year were chosen. Data for the repeat donors at the start of the experiments were compared with those at the end of the study. Blood samples were taken prior to donation. Serum protein, albumin, immunoglobulin G, A, and M, serum ferritin levels were determined by biochemical tests. RESULTS: When compared to prospective donors of 400 ml, WBC, lymphocytes, and serum ferritin levels were lower in a roughly frequency-dependent manner in female and male donor groups at the beginning of the study. All the data for the male group remained almost constant with increasing frequency of apheresis donation. However, in the female group, ferritin levels significantly decreased with over 21 donations. CONCLUSIONS: The present data showed that the serum ferritin level of the female donors decreased the most with increasing frequency of apheresis donation. The cumulative RBC left in the collecting chamber and for the laboratory test is discussed in relation to a possible cause of iron deficiency in frequent apheresis donors.

Adult↗
PubMed1999

[Clinical experiences and postoperative results with partially implantable middle ear implant].

A partially implantable middle ear implant using an ossicular vibrator of a piezoelectric ceramic bimorph has recently been developed in Japan as a new rehabilitative method for hearing. Four patients at the Miyazaki Medical College Hospital were implanted with this device between September 1994 and October 1996. Implantation of the internal component was performed under local anesthesia after confirmation of sufficient sensitivity to the ossicular vibrator in an intraoperative vibratory hearing test. All patients regained socially useful hearing with the middle ear implant without any foreign body reactions or recurrence of otitis media. None of the cases showed any elevations of bone conduction thresholds 2 to 4 years postoperatively. Natural and clear sounds without interference noise and howling due to acoustic feedback were highly satisfactory in all patients. However, the first case, who had an implant in an ear following cholesteatoma surgery using the intact canal wall technique, experienced about a 10dB deterioration of the average hearing level with the implant 2 years after implantation. Gradual deterioration appeared to be caused by the retracted tympanic membrane interfering with the mobility of the ossicular vibrator. The following three cases were implanted in ears previously operated on by radical mastoidectomy, showing stable or improving hearing results with the implant. Closure of the external canal skin at the cartilaginous portion at the time of implantation seemed appropriate to maintain a sufficient middle ear space for the ossicular vibrator to work properly. Our case study confirms that the partially implantable middle ear implant is a safe and useful tool for patients with mixed deafness which cannot be satisfactorily rehabilitated by tympanoplasty and/or a conventional hearing aid.

Deafness↗
PubMed1999

[Pulmonary malignant fibrous histiocytoma (inflammatory type) showing intracavitary fungus ball-like shadow].

We report a rare case of primary malignant fibrous histiocytoma of the lung showing intracavitary fungus ball-like shadows. Fiberoptic bronchoscopy revealed no visible tumor, but adenocarcinoma cells were detected in samples of lavage fluid from the cavitary lesion. Staging procedures (T 2 N 0 M 0) confirmed that there were no metastatic lesions. A complete resection of the left lower lobe was performed. The tumor showed polypoid growth that obstructed a small peripheral bronchus, and formed a cavitary lesion. It was histologically diagnosed as an inflammatory type of malignant fibrous histiocytoma, and consisted of atypical histiocyte-like cells, neutrophils, lymphocytes, foamy cells, and fibroblast-like cells in a storiform pattern. The patient has been in complete remission for 3 years after surgery.

Histiocytoma, Benign Fibrous↗
PubMed1999

[Causative organisms of acute otitis media and acute sinusitis in children and their susceptibility of oral beta-lactam antibiotics].

The clinical efficacy of cefditoren pivoxil (CDTR-PI) was evaluated for 43 pediatric patients with acute otitis media or acute sinusitis. The causative organisms were identified and their susceptibilities to 6 oral beta-lactam antibiotics were measured; ampicillin (ABPC), cefaclor (CCL), cefdinir (CFDN), cefditoren pivoxil (CDTR-PI), cefteram pivoxil (CFTM-PI) and cefpodoxime proxetil (CPDX-PR). The ages of 43 patients were distributed from 4 months to 10 years and 7 months, and especially children under 4 years accounted for 72% (31 cases). In 22 cases (51%), Haemophilus influenzae or Streptococcus pneumoniae were identified as the pathogens, but in 18 cases, no causative organisms were defined. Treatment by CDTR-PI was successful in 12 cases out of 15 evaluable cases in which H. influenzae or S. pneumoniae were identified as the main causative organisms. From the susceptibility testing of them, some strains of H. influenzae were found to be ABPC-resistant and some strains of S. pneumoniae were benzylpenicillin (PCG)-resistant. To support above clinical evaluation of CDTR-PI, susceptibility testings on clinically isolated H. influenzae (81 strains) and S. pneumoniae (79 strains) were performed using above mentioned 6 oral beta-lactam antibiotics. The MIC80s against H. influenzae were; CDTR-PI 0.06 microgram/ml, CCL 2 micrograms/ml, CPDX-PR 0.125 microgram/ml, CFTM-PI 0.03 microgram/ml, CFDN 1 microgram/ml and ABPC 1 microgram/ml. Those against S. pneumoniae were; CDTR-PI 0.5 microgram/ml, CCL > 4 micrograms/ml, CPDX-PR 2 micrograms/ml, CFTM-PI 1 microgram/ml, CFDN 2 micrograms/ml and ABPC 1 microgram/ml. From those results, it was concluded that CDTR-PI or CFTM-PI may be preferable for the treatment of acute otitis media and acute sinusitis in children.

Acute Disease↗