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Takeo Sakai

Publications and source records attributed to Takeo Sakai.

At least 37 records · Page 2Linked to original sources
PubMed2004

N-Allyl-N-tert-butyldimethylsilylamine for chiral ligand-controlled asymmetric conjugate addition to tert-butyl alkenoates.

The chiral ligand controlled asymmetric conjugate addition reaction of lithium N-allyl-N-(tert-butyldimethylsilyl)amide to alkenoates proceeded smoothly to give, after protodesilylation, the corresponding 3-allylaminoalkanoates with high enantioselectivities in high yields. The allyl group on the nitrogen atom was easily removable to afford 3-aminoalkanoates.

Journal Article↗
PubMed2004

Prevalence of dogs with intestinal parasites in Tochigi, Japan in 1979, 1991 and 2002.

A total of 772 canine fecal specimens were collected in Tochigi in 1979, 1991 and 2001. The frequency of dogs that were kept indoor in 2002 (72.8%) was significantly higher than that for 1979 (21.2%, P < 0.001) and 1991 (40.6%, P < 0.01). The frequency of parasitized dogs in 2002 (18.8%) was significantly lower than that for 1979 (41.9%, P < 0.01). The findings of this study confirm the declining trend in Japan in the prevalence of helminth parasites in dogs, particularly Ancylostoma caninum and Trichuris vulpis. The reduction in the frequency of dogs with helminths may be mainly a result of the improvement in the environment and the routine use of filaricides.

Animals↗
PubMed2004

Generation and characterization of P gene-deficient rabies virus.

Rabies virus (RV) deficient in the P gene was generated by reverse genetics from cDNA of HEP-Flury strain lacking the entire P gene. The defective virus was propagated and amplified by rescue of virus, using a cell line that complemented the functions of the deficient gene. The P gene-deficient (def-P) virus replicated its genome and produced progeny viruses in the cell lines that constitutively expressed the P protein, although it grew at a slightly retarded rate compared to the parental strain. In contrast, no progeny virus was produced in the infected host when the def-P virus-infected cells that did not express the P protein. However, we found that the def-P virus had the ability to perform primary transcription (by the virion-associated polymerase) in the infected host without de novo P protein synthesis. The def-P virus was apathogenic in adult and suckling mice, even when inoculated intracranially. Inoculation of def-P virus in mice induced high levels of virus-neutralizing antibody (VNA) and conferred protective immunity against a lethal rabies infection. These results demonstrate the potential utility of gene-deficient virus as a novel live attenuated rabies vaccine.

Animals↗
PubMed2004

Displacement of the reticular lamina with and without the tectorial membrane in the guinea pig cochlea.

OBJECTIVE: In an attempt to establish the mechanical relationships between the reticular lamina and tectorial membrane, we studied the morphological changes of the reticular lamina on a micrometer scale when an in vitro preparation of guinea pig cochlea with and without tectorial membrane was exposed to a potassium-rich medium. MATERIAL AND METHODS: Using video-enhanced differential interference contrast microscopy, the radial displacement of the inner hair cells (IHCs) and outer hair cells (OHCs) in the reticular lamina was measured in real time after exposure to the potassium-rich medium for 3 min. RESULTS: The amplitude of the displacement of the OHCs in preparations with an intact tectorial membrane was half of that observed in those in which the tectorial membrane had been removed. A similar displacement response was also observed for the IHCs, although it was smaller than that for the OHCs. There was no significant difference in the amplitude of the displacement among the three rows of OHCs. CONCLUSIONS: These results suggest that the structure linking the OHCs to the pillar cells is very elastic and that the movement of the OHCs in situ is weakly mechanically coupled to the IHCs. The tectorial membrane provides increased compliance in the motion of the IHCs and OHCs.

Action Potentials↗
PubMed2004

Augmenting effect of antibiotics on endotoxin activity may cause a safety problem.

Enhancing/interfering effect of antibiotics on endotoxin was evaluated using the endotoxin test and the cell line assay in 28SC cells that has a responsiveness consistent with that of human peripheral blood. When a total of 21 products of seven different kinds of antibiotics were tested, none showed any significant effect on the endotoxin test at its therapeutic dose. However, aminoglycosides showed a significant augmenting effect on IL-6 induction of endotoxin in 28SC cells. Detailed examination of the augmenting effect was made on spectinomycin in the in vitro cell line assay and also in the lethal endotoxin challenge assay in D -galactosamine-treated mice. Spectinomycin also enhanced the endotoxin lethality in D -galactosamine-treated mice. A kinetic analysis in endotoxin-sensitized 28SC cells revealed that the augmentation takes place as quickly as 10 min after spectinomycin treatment. Accordingly, a special caution concerning the augmenting effect was assumed necessary for the safety control of antibiotic products as well as for selecting antibiotics for the therapeutic use.

Animals↗
PubMed2004

Genetic characterization of rabies viruses isolated from frugivorous bat (Artibeus spp.) in Brazil.

In Latin America, rabies cases related to frugivorous bats have been reported since 1930's. Recently, two viruses isolated from Artibeus lituratus were proved to be vampire bat variants by monoclonal antibodies panels [2], but their genetic information is not well known. In this report, four rabies viruses were isolated from frugivorous bats (Artibeus spp.) in Brazil and their nucleoprotein gene sequences were determined. These isolates were found to be genotype 1 of lyssavirus and showed the maximum nucleotide sequence homology of 97.6-99.4% with vampire bat-related viruses in Brazil [6]. These results indicate that the Brazilian frugivorous bat rabies viruses in this study are closely related to vampire bat-related viruses that play a main role in rabies virus transmission to livestock in Brazil.

Animals↗
PubMed2004

Genetic and serological characterization of novel serotype G8 bovine group A rotavirus strains isolated in Japan.

G8 bovine group A rotaviruses isolated in Japan were genetically and serologically characterized. The VP7 gene nucleotide and amino acid sequences revealed high identity with each other. All Japanese G8 strains were classified into the same lineage in the phylogenetic analysis based on VP7 gene sequences. Antisera to four Japanese G8 strains neutralized other G8 strains, but their neutralizing titers were between 8-fold lower and 2-fold higher than homologous strains. These results suggest that the VP7s of Japanese G8 strains have similar genetic and serologic characteristics. Observed differences in the neutralizing abilities of antisera for each strain appear to depend on differences in the P serotypes/genotypes.

Amino Acid Sequence↗
PubMed2004

Genetic and phylogenetic analysis of glycoprotein of rabies virus isolated from several species in Brazil.

Genetic and phylogenetic analyses of the region containing the glycoprotein (G) gene, which is related to pathogenicity and antigenicity, and the G-L intergenic region were carried out in 14 Brazilian rabies virus isolates. The isolates were classified as dog-related rabies virus (DRRV) or vampire bat-related rabies virus (VRRV), by nucleoprotein (N) analysis. The nucleotide and amino acid (AA) homologies of the area containing the G protein gene and G-L intergenic region were generally lower than those of the ectodomain. In both regions, nucleotide and deduced AA homologies were lower among VRRVs than among DRRVs. There were AA differences between DRRV and VRRV at 3 antigenic sites and epitopes (IIa, WB+ and III), suggesting that DRRV and VRRV can be distinguished by differences of antigenicity. In a comparison of phylogenetic trees between the ectodomain and the area containing the G protein gene and G-L intergenic region, the branching patterns of the chiropteran and carnivoran rabies virus groups differed, whereas there were clear similarities in patterns within the DRRV and VRRV groups. Additionally, the VRRV isolates were more closely related to chiropteran strains isolated from Latin America than to Brazilian DRRV. These results indicate that Brazilian rabies virus isolates can be classified as DRRV or VRRV by analysis of the G gene and the G-L intergenic region, as well as by N gene analysis.

Amino Acid Sequence↗
PubMed2004

Cerebellopontine angle meningioma expanding into the sella turcica in a dog.

A 10-year-old, female poodle was presented with left paresis and vestibular signs, following left enophthalmus and atrophy of the cheek. Magnetic resonance imaging revealed a mass along the base of the brain and extending from the left cerebellopontine angle to the sella turcica. The mass showed isointensity on the T1-weighted image and T2-weighted image, and was enhanced by contrast medium (Gd-DTPA). Although occipital craniotomy was carried out and the mass removed, the dog died without recovering from the anesthesia. The tumor was diagnosed pathologically as fibroblastic meningioma.

Animals↗
PubMed2004

The Tohoku Study of Child Development: A cohort study of effects of perinatal exposures to methylmercury and environmentally persistent organic pollutants on neurobehavioral development in Japanese children.

Several birth cohort studies have shown adverse effects of perinatal exposures to methylmercury (MeHg) and environmentally persistent organic pollutants (POPs). These chemicals are ingested mainly through fish consumption, but little is known about the hazardous effects in Japanese, whose fish consumption is high. The present study, the Tohoku Study of Child Development, was designed to examine the effects of perinatal exposures to MeHg, polychlorinated biphenyls (PCB), dioxins, pesticides, and other chemicals in Japanese children. Six hundred eighty-seven pregnant women were participated in this study with their written informed consent. Maternal peripheral blood, cord blood, cord tissue, placenta, and breast milk samples were collected for chemical analysis. Maternal hair was also taken for MeHg analysis. Infants born at full term were assessed by neurobehavioral tests: the Brazelton Neonatal Behavioral Assessment Scale at three days old, the Kyoto Scale of Psychological Development and the Bayley Scales of Infant Development at 7 and 18 months old, and the Fagan Test of Infant Intelligence at 7 months old. The children will be continuously followed up to ages 6-7 years. Maternal food intake frequency, maternal IQ, socioeconomic status, and home environment were assessed as covariates. The results of this cohort study will allow us to evaluate associations between the neurobehavioral development of children and perinatal exposures to MeHg and environmentally POPs in Japan.

Animals↗
PubMed2003

An improved method for recovering rabies virus from cloned cDNA.

A new system for recovery of rabies virus from cDNA plasmid, the transcription of which was driven by cellular RNA polymerase II, was developed. The plasmid contains full-length viral cDNA flanked by hammerhead ribozyme and hepatitis delta ribozyme sequences, arranged downstream of the cytomegalovirus (CMV) promotor. Transfection with the full-length cDNA plasmid together with helper plasmids encoding viral N, P, and L proteins without supply of T7 RNA polymerase produced a recombinant rabies virus in several cell lines. The efficiency of recovery between the conventional T7 promotor system and the new CMV promotor system was compared using these plasmid constructs. The newly established system is applicable to various cell lines and allows rapid and efficient generation of recombinant rabies virus.

Animals↗
PubMed2003

Three-dimensional CT image analysis of the digging system in the aardvark.

We examined the bone movement in the forepaw and hind paw in the aardvark (Orycteropus afer) by using three-dimensional (3D)-computed tomography (CT) techniques and osteometrical methods to confirm the functional adaptation of the extremities as a digging system. The four metacarpal bones could be strongly bent from the distal carpal bones. The distal end of the second and third metacarpal bones possessed enlarged smooth articulation surfaces that allowed the proximal phalanx to bend at a sharp angle. However, the articulation surface was not well-developed in the distal end of the fourth and fifth metacarpal bones and the proximal phalanx could bend at smaller angle in these two lateral digits. The proximal phalanges sharply crook from the metatarsal in the first, second, third and fourth digits in the hind paw. We suggest that the medial two digits in the forepaw directly contribute to the crushing, when these proximal phalanges crook in the phase of power stroke. In contrast the lateral third and fourth digits may act as sweeper of the crushed soil. These suggestions regarding the different functional adaptation between medial two digits and lateral two digits are consistent with the anatomical data of the forearm musculature. In the hind paw, we suggest that the second, third and fourth digits are functionally similar and that the hind paw may not act as a crushing apparatus but as a running motor or soil-sweeper similarly using these main three digits.

Animals↗
PubMed2003

Discrimination between dog-related and vampire bat-related rabies viruses in Brazil by strain-specific reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism analysis.

BACKGROUND: There is a geographical overlap between the two main rabies epidemiological cycles maintained by dogs and vampire bats in Latin America. The geographical and temporal coincidence of rabies outbreaks of respective origins is not unusual in rural areas of Latin America. These circumstances make it difficult to discriminate the intraspecies and interspecies transmission pathways of rabies. OBJECTIVE: This study was conducted to develop techniques to discriminate dog-related and vampire bat-related rabies virus isolates (DRRV and VRRV, respectively) in Brazil. STUDY DESIGN: The 1396 nucleotides of the nucleoprotein gene of a total of 27 DRRV and VRRV were sequenced. Strain-specific (SS) primers were developed based on these sequences. Forty-nine rabies virus strains isolated from animals and humans in several parts of Brazil were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) with SS primers. These rabies viruses were also amplified by RT-PCR with general rabies primers and the PCR products were cut by three restriction enzymes, Blp I, Bsu36 I and BspE I. RESULTS: All the DRRV and VRRV were distinguished by RT-PCR with SS primers. The PCR products obtained from DRRV were cut at one site by Blp I, but not by Bsu36 I. The PCR products obtained from VRRV were cut at one or two sites by Bsu36 I, but not by Blp I. Blp I and Bsu36 I clearly discriminated DRRV and VRRV in restriction fragment length polymorphysim (RFLP) assays. The results of SS RT-PCR and RFLP were consistent. CONCLUSION: SS RT-PCR and RFLP assays have been developed for determining the origins of rabies virus isolates in Brazil. These assays are simple and rapid, and will be useful for identifying the rabies virus reservoirs of field isolates in Brazil, especially when used together.

Amino Acid Sequence↗
PubMed2003

Seroprevalence of Bartonella henselae, Toxoplasma gondii, FIV and FeLV infections in domestic cats in Japan.

Seroprevalence of Bartonella henselae, Toxoplasma gondii, feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was investigated in 1,447 domestic cats derived from the north (Hokkaido) to the south (Okinawa) prefectures in Japan. Of the cats investigated, 8.8% (128/1,447) were seropositive to B. henselae, 5.4% (78/1,447) to T. gondii, 9.8% (107/1,088) to FIV, and 2.9% (32/1,088) to FeLV, respectively. For B. henselae infection, the positive rate varied from 11.5% in cats of 1 to <2 years old to 7.2% in those over 3 years old. Outdoor cats showed higher positive rate (14.5%) than that (7.0%) in indoor ones. The rate (13.5%) in flea-infested cats was significantly higher than that (7.4%) in flea-negative cats. The positive rates in southern and urban sites were more likely to be higher than those in northern and suburban sites, suggesting that warm and humid environments, density of cat population, and raising status, including hygienic condition and flea infestation in cats may correlate to higher seroprevalence of B. henselae infection. For T. gondii, FIV and FeLV infections, the seroprevalence also tended to be higher in outdoor, flea-infested cats and advanced age groups. For FIV infection, the positive rates in male (14.3%) and outdoor cats (15.0%) were significantly higher than those in female (5.0%) and indoor cats (4.6%). On the other hand, no significant difference in seropositivities was observed in FeLV and T. gondii infections concerning to both genders and raising status.

Animals↗
PubMed2003

[Investigation on zoonoses among veterinary technicians].

We conducted a survey on how much veterinary clinics staff, mostly veterinary technicians, know about zoonosis and how extensively they inform pet owners of ways to prevent zoonosis. The number of people who took part in the survey was 1,057. The ratio of people who said their knowledge on zoonosis is "neither sufficient nor insufficient" was 53.8%, which is larger than the ratio of people who replied "sufficient" or "insufficient." The percentage of those who said their way of giving information on zoonosis to pet owners is "neither sufficient nor insufficient" was 52.4%. The ratios of people who knew about Spirometra erinacei, Dipylidium canium or Giardia lamblia were 64.7%, 73.6% and 57.6%, respectively. The longer they worked, the more they knew about Cryptosporidium spp. (20.1%), Hymenolepis nana (31.8%), Echinococcus spp. (45.7%), Ancylostoma spp. (73.3%), Dirofilaria immitis (80.5%), Toxoplasma gondii (82.4%), and Toxocara canis (86.5%). It seems that systematic continuing education and opportunities to acquire new knowledge are not sufficient for those working in veterinary clinics, and this needs to be corrected.

Adult↗
PubMed2003

Risk of acquiring zoonoses by the staff of companion-animal hospitals.

The aim of this study was to obtain information on the risk of companion-animal hospital staff members acquiring zoonotic diseases. We surveyed veterinary technicians to estimate the rate of acquisition of zoonoses from pets while working in companion-animal hospitals. About one in five veterinary technicians (19.4%) reported acquiring zoonotic infections in their small-animal practice. The rate of acquisition of zoonoses by those who had worked for more than 5 years was significantly higher than by those who had worked for less than 1 year (p < 0.001, odds ratio: 6.74). The list of zoonoses included the flea bites (62.3%), dermatophytosis (26.9%), cat-scratch disease (16.0%), tick bites (9.0%), and pasturellosis (6.1%). A small number of veterinary technicians had been infected with Q fever, toxoplasmosis, parrot fever, salmonellosis, tetanus, campylobacteriosis, or scabies.

Animal Technicians↗
PubMed2003

Differences in Ibaraki virus RNA segment 3 sequences from three epidemics.

Phylogenetic tree and partial nucleotide sequence analysis of RNA segment 3 were conducted to compare the Ibaraki virus (IBAV) strains from three epidemics in Japan, and serotype 2 epizootic hemorrhagic disease virus strains isolated in Australia, Taiwan, and Canada. Each strain was classified relative to the Ibaraki disease (IBAD) epidemics, which occurred in 1959-1960, 1987, or 1997-1998. In particular, major variation of the gene was identified in the strains isolated after 1997 when a new type of IBAD with the abnormal birth was confirmed. Ibaraki viruses isolated in Japan were more closely related to Taiwanese and Australian strains based on genetics, while the Canadian strain was more distantly related.

Animals↗