Biomedical subjects

Y Maki

Publications and source records attributed to Y Maki.

At least 37 records · Page 2Linked to original sources

PubMed2000

Stoichiometric analysis of barley plastid ribosomal proteins.

We analyzed the protein composition of plastid 70S ribosomes isolated from the stromal fractions of barley plastids by the radical-free and highly reducing method of two dimensional polyacrylamide gel electrophoresis (RFHR 2D-PAGE). Intactness of the ribosomes was confirmed by the poly(U)-directed phenylalanine polymerization activity and by the reassociation capacity of the subunits into 70S ribosomes. The small and large ribosomal subunits were composed of 23 and 36 proteins, respectively. In addition, one acidic protein associated with ribosomes in low salt buffer but released in high salt buffer was found. The plastid ribosomes contained relatively larger numbers of acidic proteins than prokaryotic ribosomes. Stoichiometric analysis revealed the presence of several ribosomal proteins in low copy numbers, indicating that the ribosomes of plastids were heterogeneous. We also investigated the protein composition of plastid ribosomes from greening barley leaves and found that it did not change during greening.

Centrifugation, Density Gradient↗

PubMed1999

Increased susceptibility to Toxoplasma gondii infection in SAG-1 transgenic mice.

SAG-1, one of the major surface proteins of Toxoplasma gondii, has been reported to play an important role in immune and pathogenic mechanisms of the parasites but its exact function is still unclear. We investigated the time courses of T. gondii infection in B6C3F1 transgenic mice carrying the SAG-1 gene. SAG-1 transgenic mice were infected intraperitoneally with a high virulent RH strain or a low virulent Beverley strain of T. gondii. When infected with RH strain tachyzoites, no significant differences in time courses of survivals between SAG-1 transgenic and wild-type mice were observed. Both groups succumbed to an acute infection within 8 days after infection. However, a lower survival rate (20%) was observed in SAG-1 transgenic mice than in wild-type (80%), when infected with Beverley strain cysts. This result indicates that SAG-1 transgenic mice are more susceptible to T. gondii infection as compared with their wild-type counterpart. ELISA using recombinant SAG-1 protein indicates that SAG-1 transgenic mice do not produce antibodies to the SAG-1 molecule. These findings may provide a critical tool for analysing the molecular mechanisms of pathogenesis and host immune responses during toxoplasmosis.

Animals↗

PubMed1999

Flexor tendon repair in a rabbit model using a "core" of extensor retinaculum with synovial membrane. An experimental study.

In this histological and biomechanical study in two groups of rabbits, a piece of the extensor retinaculum with its synovial membrane was inserted as a biological "core" into a hole at the centre of both stumps of a severed tendon, which was repaired with interrupted sutures. In the other group, the tendon was sutured without a "core". In the "core" group, proliferation and migration of fibroblasts from both tendon surfaces and the "core" surface toward the deep layer of the suture site was seen 2 weeks after operation. New collagen fibres, aligned parallel to the long axis of the tendon, could also be seen 4 weeks after operation, and healing was more advanced than in the coreless model. The maximum force to produce a gap in the "core" tendon was 82% greater than in the coreless tendon 4 weeks after operation.

Animals↗

PubMed1999

Experimental study of two new flexor tendon suture techniques for postoperative early active flexion exercises.

We used a rabbit model to test the postoperative mechanical strengths of two new tendon suture techniques. These were compared with the conventional modified Kessler and double looped suture techniques. For each technique, maximum load until 3 mm gap, load at 1 mm gap and ultimate load were measured at the time of operation and at weeks 1 and 3 after operation. Maximum load until 3 mm gap and load at 1 mm gap were significantly higher in the new techniques than in the conventional techniques at the time of operation and at 1 week; there was no statistical difference between the four techniques at 3 weeks. No technique resulted in a decrease in maximum load until 3 mm gap, load at 1 mm gap and ultimate load at 1 week. The new techniques reported here have the potential to withstand early active flexion exercises.

Animals↗

PubMed1999

Comparison of the neurotropic effects of motor and sensory Schwann cells during regeneration of peripheral nerves.

We examined the inductive ability of motor and sensory Schwann cells on regeneration of motor and sensory axons using a silastic Y chamber, and Lewis rats L5 ventral root (motor) and saphenous nerve (sensory). We developed four experimental models: motor-motor nerve group-proximal motor stump with distal fresh and frozen/thawed motor nerve segments (n = 7); sensory-sensory nerve group-proximal sensory stump with distal fresh and frozen/thawed sensory nerve segments (n = 7); motor-sensory nerve group-proximal motor stump with distal fresh and frozen/thawed sensory segments (n = 8); and sensory-motor nerve group-proximal sensory stump with distal fresh and frozen/thawed motor segments (n = 8). The gap was set at 4 mm. Six weeks postoperatively we compared the number of regenerated myelinated axons in the two distal channels, and found that sensory Schwann cells have a strong inductive ability for regeneration of both sensory and motor axons. Motor Schwann cells have weak inductive ability for regeneration of motor axons and no inductive ability for regeneration of sensory axons.

Animals↗

PubMed1999

Both stump area and volume of distal sensory nerve segments influence the regeneration of sensory axons in rats.

We examined the influence of both stump area and volume of a distal sensory nerve segment on neurotropic induction of regenerating sensory axons in a rat saphenous nerve model. In group 1 (n = 10) the proximal stump of the severed saphenous nerve was inserted into the proximal channel, and a 2 cm free nerve segment and a double-barrelled 1 cm free nerve segment were inserted into the distal two channels of a silicone Y-chamber. In group 2 (n = 10), 2 cm and 1 cm free nerve segments were inserted into the distal two channels of a Y-chamber. The gap between the stumps was set at 4 mm. After six weeks, we counted and compared the number of regenerated myelinated sensory axons in the distal two channels. Significantly more axons regenerated in the wider stump area channel of group 1 and in the larger volume channel of group 2 than in the opposite channel in either group (p < 0.05 in each case).

Animals↗

PubMed1999

Lack of topographical specificity in peripheral nerve regeneration in rats.

In a previous study we found that sensory regeneration was neurotropically selective regardless of the end organ, but motor regeneration was not, which made us doubt the existence of topographic specificity. The purpose of the present study was to confirm the existence of topographic specificity in rats. The proximal stump of either the peroneal or tibial nerve was inserted into the proximal limb of a silicone Y-chamber. Both distal stumps of peroneal and tibial nerve were inserted into the distal limbs. The gap between the stumps was set at either 4 mm (n = 8, on each subgroup) or 8 mm (n = 8, on each subgroup). Six weeks later the number of regenerated axons in the distal two limbs were counted and compared. The number of regenerated axons towards the distal tibial nerve side was significantly larger in every model. Regenerated axons from the proximal peroneal stump did not preferentially choose the distal peroneal stump. The existence of topographic specificity is unlikely.

Animals↗

PubMed1999

Changes in quinone profiles of hot spring microbial mats with a thermal gradient

The respiratory and photosynthetic quinones of microbial mats which occurred in Japanese sulfide-containing neutral-pH hot springs at different temperatures were analyzed by spectrochromatography and mass spectrometry. All of the microbial mats that developed at high temperatures (temperatures above 68 degreesC) were so-called sulfur-turf bacterial mats and produced methionaquinones (MTKs) as the major quinones. A 78 degreesC hot spring sediment had a similar quinone profile. Chloroflexus-mixed mats occurred at temperatures of 61 to 65 degreesC and contained menaquinone 10 (MK-10) as the major component together with significant amounts of either MTKs or plastoquinone 9 (PQ-9). The sunlight-exposed biomats growing at temperatures of 45 to 56 degreesC were all cyanobacterial mats, in which the photosynthetic quinones (PQ-9 and phylloquinone) predominated and MK-10 was the next most abundant component in most cases. Ubiquinones (UQs) were not found or were detected in only small amounts in the biomats growing at temperatures of 50 degreesC and above, whereas the majority of the quinones of a purple photosynthetic mat growing at 34 degreesC were UQs. A numerical analysis of the quinone profiles was performed by using the following three parameters: dissimilarity index (D), microbial divergence index (MDq), and bioenergetic divergence index (BDq). A D matrix tree analysis showed that the hot spring mats consisting of the sulfur-turf bacteria, Chloroflexus spp., cyanobacteria, and purple phototrophic bacteria formed distinct clusters. Analyses of MDq and BDq values indicated that the microbial diversity of hot spring mats decreased as the temperature of the environment increased. The changes in quinone profiles and physiological types of microbial mats in hot springs with thermal gradients are discussed from evolutionary viewpoints.

Journal Article↗

PubMed1999

Interleukin-12, interferon-gamma and interleukin-4 gene expression in cats infected with Toxoplasma gondii.

Interleukin-12, Interferon-gamma and Interleukin-4 mRNA levels in cells of the spleen and mesenteric lymph nodes of cats following primary and secondary infection with Toxoplasma gondii were examined by a semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) method. Expression of Interleukin-12p40 mRNA and Interferon-gamma mRNA was observed after primary and secondary oral infection with Toxoplasma gondii. In contrast, no expression of IL-4 mRNA in the spleen and little expression in the mesenteric lymph nodes were observed after primary infection when the cats shed oocysts, however, the expression of IL-4 mRNA observed in the cats after secondary inoculation.

Animals↗

PubMed1999

Gender differences in oral health behavior and general health habits in an adult population.

This study aimed to evaluate gender differences in oral health behavior and general health habits in adults. The subjects were 207 males and 196 females aged 20-64 yrs who were public officials in the city or town administrations in Chiba Prefecture, Japan. The questionnaire survey included three items: (1) self assessment of oral health status, (2) oral health behavior and (3) general health habits. Statistical analysis was performed using the chi-square test for differences of responses between males and females. The proportion of subjects with cognition of symptoms of oral disease ranged from 14.3 to 23.0%. The percentage of those who had not visited a dentist in the last year were 52.7% for males and 36.7% for females (p < 0.01). Subjects who brushed their teeth almost every day at bed time were 60.9% of males and 88.8% of females (p < 0.01). A comparison of the numbers of positive responses regarding general health habits found no differences in the distribution of general health habits score between males and females. Examining the relationship between oral health behavior and general health habits revealed that males with general habit high scores tended to have positive oral hygiene behavior. These results support the thesis that gender specificities in oral health depend on individual attitudes to oral health and dental utilization. In addition, understanding the cognitive factors of males and females would accelerate dental approaches to modifying oral health behavior of both groups, thus contributing to lifelong health maintenance.

Adult↗

PubMed1998

Substrate specificity of thermostable farnesyl diphosphate synthase with alkyl group homologs of isopentenyl diphosphate.

3-Alkyl group homologs of isopentenyl diphosphate were examined for the reactivity as substrates of the thermostable farnesyl diphosphate (FPP) synthase of Bacillus stearothermophilus. Even 3-n-propyl- and 3-n-butyl-but-3-enyl diphosphates, which are hardly acceptable by animal FPP synthases, are accepted by this bacterial enzyme as substrates to react with dimethylallyl- and geranyl diphosphates, yielding 7-methyl-3-n-propylocta-2,6-dienyl- and 7,11-dimethyl-3-n-propyldodeca-2,6,10-trienyl diphosphate, respectively.

Alkyl and Aryl Transferases↗

PubMed1998

Two subunits of heptaprenyl diphosphate synthase of Bacillus subtilis form a catalytically active complex.

Heptaprenyl diphosphate synthase of Bacillus subtilis, which participates in the biosynthesis of the side chain of menaquinone-7, is composed of two dissociable subunits, component I and component II, which are encoded by two cistrons in a novel gene cluster of gerC operon [Zhang, Y.-W., et al. (1997) J. Bacteriol. 179, 1417-1419]. This enzyme essentially requires the coexistence of both subunits for its catalysis. Expression vector systems for the two structural genes, gerC1 and gerC3, were constructed separately, and the two components were overproduced in Escherichia coli cells. After purification, their dynamic interactions in forming a catalytically active complex were investigated by gel filtration and immunoblotting analyses. When a mixture of the two components that had been preincubated in the presence of Mg2+ and farnesyl diphosphate was subjected to Superdex 200 gel filtration, a significant elution peak appeared in a region earlier than those observed when they were chromatographed individually. This fraction contained both components I and II, and it corresponded to a molecular mass that is in accord with the sum of the values of the two components. Cross-linking studies indicate that the two essential subunits, farnesyl diphosphate, and Mg2+ form a ternary complex which seems to represent a catalytically active state of the heptaprenyl diphosphate synthase. On the other hand, no complex was formed in the presence of isopentenyl diphosphate or inorganic pyrophosphate and Mg2+. A photoaffinity analogue of farnesyl diphosphate was shown to preferentially label the component I protein, suggesting that component I possesses a specific affinity for the allylic substrate. Furthermore, the photoaffinity labeling of component I significantly increased in the presence of component II. The mechanism of catalysis of this unique heteromeric enzyme is understood by assuming that association and dissociation of the two subunits facilitate turnover of catalysis for the synthesis of the amphipathic product from soluble substrates.

Alkyl and Aryl Transferases↗

PubMed1998

Phylogenetic evidence for the existence of novel thermophilic bacteria in hot spring sulfur-turf microbial mats in Japan.

So-called sulfur-turf microbial mats, which are macroscopic white filaments or bundles consisting of large sausage-shaped bacteria and elemental sulfur particles, occur in sulfide-containing hot springs in Japan. However, no thermophiles from sulfur-turf mats have yet been isolated as cultivable strains. This study was undertaken to determine the phylogenetic positions of the sausage-shaped bacteria in sulfur-turf mats by direct cloning and sequencing of 16S rRNA genes amplified from the bulk DNAs of the mats. Common clones with 16S rDNA sequences with similarity levels of 94.8 to 99% were isolated from sulfur-turf mat samples from two geographically remote hot springs. Phylogenetic analysis showed that the phylotypes of the common clones formed a major cluster with members of the Aquifex-Hydrogenobacter complex, which represents the most deeply branching lineage of the domain bacteria. Furthermore, the bacteria of the sulfur-turf mat phylotypes formed a clade distinguishable from that of other members of the Aquifex-Hydrogenobacter complex at the order or subclass level. In situ hybridization with clone-specific probes for 16S rRNA revealed that the common phylotype of sulfur-turf mat bacteria is that of the predominant sausage-shaped bacteria.

Bacteria↗

PubMed1998

Monoclonal antibody against Babesia equi: characterization and potential application of antigen for serodiagnosis.

Monoclonal antibody (MAb) BEG3 was produced against Babesia equi parasites to define a species-specific antigen for diagnostic use. The MAb reacted with single, paired, and Maltese cross forms of B. equi, and no reaction was observed with this MAb on acetone-fixed Babesia caballi, Babesia ovata, or Babesia microti parasites in the indirect immunofluorescent antibody test. Confocal laser and immunoelectron microscopic studies showed that the antigen which was recognized by this MAb was located on the surface of B. equi parasites. This MAb recognized a 19-kDa protein of B. equi antigen and did not react with B. caballi antigen or normal horse erythrocytes in immunoblot analysis. This MAb also significantly inhibited the in vitro growth of the B. equi parasite. Preliminary studies using partially purified antigen, which was separated by high-pressure liquid chromatography and recognized by the MAb, suggested that it is a suitable antigen for enzyme-linked immunosorbent assay detection of anti-B. equi antibodies in naturally infected horse sera.

Animals↗

PubMed1998

Transcriptional analysis of Marek's disease virus (MDV) genes in MDV-transformed lymphoblastoid cell lines without MDV-activated cells.

Spontaneously activated MDV is rarely included in MDV-transformed cells, while it may influence the results of transcriptional analysis. A population consisting of 10(3) MDV-transformed cells probably did not include spontaneously activated MDV, since the estimated frequency of MDV-transformed cells including activated MDV was below 0.01% according to limiting-dilution polymerase chain reaction (PCR) and the presence of the major early antigen pp38 in 6 transformed cell lines. Reverse transcriptase-PCR (RT-PCR) products corresponding to ICP27, pol, TK, US3, A41, gA, gB and UL50 genes were undetectable in 10(3) cells by Southern hybridization of the RT-PCR products. Transcripts of the VP16 and SORF2 genes were detected in the 10(3) cells of MSB-1, and the pp14 gene transcript was found in 10(3) cells of RPL-1 but not in 10(3) cells of HPRS-1, MOGA-2, MSB-1 or MTB-1. A transcript corresponding to the ICP4 sequence was detected as a 0.7 kbp RT-PCR product in 10(3) cells of these MDV cell lines but not in the retrovirus-transformed 1104B1 cell line. The transcript corresponding to the 0.7 kbp RT-PCR product suggested a splice by its size and sequence. Thus, transcriptional analysis of 10(3) MDV-transformed cells revealed that the transcript corresponding to the ICP4 sequence was a common transcript in latently infected MDV-transformed cells, while most of the genes did not transcribe in these cells.

Animals↗

PubMed1998

[Combination chemotherapy with cis-platinum and ifosfamide for hormone unresponsive prostate cancer].

PURPOSE: There is no effective therapy against hormone refractory prostate cancer. This led us to evaluate the effectiveness and toxicity of cis-platinum (CDDP) and ifosfamide (IFM) combination chemotherapy in the patients with hormone-unresponsive carcinoma of the prostate. METHODS: Patients with hormone-unresponsive prostate cancer were scheduled to receive CDDP 70 mg/m2 intravenously on day 1 and IFM 1.2 g/m2/day intravenously on day 1 through day 5 of 28-day cycle. RESULTS: Twenty seven patients with hormone unresponsive prostate cancer were enrolled onto this trial. Of these patients, seven (26%) demonstrated a partial objective response (PR), and ten (37%) a stable disease (ST). The response duration of PR cases lasted from 6 to 49 months with a median of 16 months and the response duration of PR + ST cases lasted from 3 to 36 months with a median of 10 months. Subjective improvement was obtained in 11 patients (41%). Survival duration of all cases were 4 to 89 months with a median of 23 months and probabilities of survival at 3 years and 5 years were 36% and 24%, respectively. The toxicity of this treatment was mostly mild to moderate, anemia (96%), leukocytopenia (89%), anorexia (81%), alopecia (67%), thrombocytopenia (44%), hematuria (38%), renal dysfunction (19%) and liver dysfunction (7%) were noticed. Severe toxicity was observed in two cases, one acute renal failure and one endotoxin shock. CONCLUSION: We conclude that CDDP and IFM combination chemotherapy was active regimen for hormone unresponsive prostate cancer.

Aged↗

PubMed1997

Blood flow in mobilized nerves: results in a rabbit sciatic nerve model.

The purpose of this study was to evaluate the immediate effect on capillary blood flow of surgical mobilization of 15 cm of the rabbit sciatic and tibial nerve. Capillary nerve blood flow was determined with 16-micron radioactive microspheres. Thirty-seven rabbits were divided into six groups. In the control group A (n = 7), the in situ nerve blood flow was determined. In group B (n = 7), the nerve was mobilized, leaving only the proximal and distal endoneurial vascular supplies; blood flow increased compared with in situ values in most segments. In group C (n = 5), the nerve was mobilized as in group B, but also transected distally; blood flow was markedly decreased in the distal segments but was maintained up to a diameter-to-length ratio of 1:63. In group D (n = 6), the nerve was not mobilized, but was transected proximally and distally; blood flow increased in all segments. In group E (n = 5), the nerve was mobilized and transected proximally and distally, leaving only nerve branches intact; blood flow was significantly higher in segments of the nerve from which nerve branches originated with the nerve receiving blood flow through its branches. In group F (n = 6), the nerve was mobilized, all extrinsic vessels except one were transected, and the proximal and distal nerve was transected; flow was maintained to a diameter:length ratio of 1:41 from the source of blood flow. Therefore, it does appear that long lengths of nerve may be mobilized and transposed while maintaining sufficient blood flow.

Animals↗

PubMed1997

Epitope regions in the heavy chain of Clostridium botulinum type E neurotoxin recognized by monoclonal antibodies.

Seventeen monoclonal antibodies (MAbs) were previously established against the heavy chain (Hc) of botulinum type E neurotoxin in BALB/c mice immunized with the type E toxoid. Five MAbs (LE15-5, LE34-6, EK19-7, EK21-4, and AE27-9) showed toxin-neutralizing activity in mice. Two of the five MAbs, EK19-7 and EK21-4, recognized the regions located at amino acid positions 731 to 787 and 811 to 897, respectively. One of the remaining three antibodies (LE34-6) reacted with the amino acid sequence VIKAIN, at amino acid positions 663 to 668, closed by the ion channel-forming domain. It is suggested that the ion channel-forming domain may also be associated with the blocking of acetylcholine release. Furthermore, the amino acid sequence YLTHMRD within 30 residues of the C-terminal region of the Hc component seemed to be recognized by LE15-5. It has been reported that the binding domain of the type E toxin is located on the C-terminal half of the Hc component. Therefore, the neutralizing activity of LE15-5 antibody may be attributed to its ability to block the binding of neurotoxin to the receptor of target cells.

Amino Acid Sequence↗