Biomedical subjects
Publications and source records attributed to Y Oku.
The participation of platelets in the protection against larval Taenia taeniaeformis was studied. CB-17 SCID mice, susceptible to T. taeniaeformis, were protected against a challenge infection with T. taeniaeformis by the passive transfer of platelets from T. taeniaeformis-infected normal CB-17 mice, resistant to T. taeniaeformis.
Alveolar hydatidosis by Echinococcus multilocularis (Em) infection occurred on a 22-year-old (approx.) male gorilla (Gorilla gorilla) and a 4-year-old female ring-tailed lemur (Lemur catta) in a zoo, in Hokkaido, Japan. Case 1: The gorilla presented neurologic signs in course of nine months and died. Pathologically, alveolar hydatid lesions were found in the liver, the liver-associated lymph nodes, the cerebrum, and the lungs. A protoscolex was found only in one hepatic cyst. Case 2: In the lemur, large masses of hydatide cysts were found on the liver and at the lung-associated lymph nodes. Cysts contained numerous calcareous corpuscles and protoscolices. The lemur appears a favorable intermediate-host for Em. The identification of Em in both cases were confirmed by PCR.
Golden hamsters as alternative definitive hosts of Echinococcus multilocularis were used for coproantigen detection by means of sandwich ELISA. The test was performed in hamsters infected with approximately 20,000, 4,000, 500, 0 (control) and 100,000 (i.e., group I, II, III, IV and V respectively) protoscoleces. Comparison of mean OD values of each group showed significant differences depending on the number of protoscoleces administered and days postinfection. There was also a relatively high statistical correlation between the number of recovered worms and ELISA OD values (correlation coefficient = 0.699, P < 0.05), although accurate comparison of worm burdens among individual animals was difficult when numbers of infecting worms fell within the same range.
We examined the relationships among dyspnea ratings in daily life, the physiologic state, and anxiety and depression of fifty-two patients with chronic obstructive disease (COPD) during long-term domiciliary oxygen therapy (LTOT). Clinical ratings of dyspnea were assessed by the visual-analog scale (VAS) during eight types of basic behavior in indoor daily life. Analysis of the physiologic state included forced expiratory volume in 1 second (FEV1.0), and arterial blood gas (PaO2, PaCO2) at rest while breathing room air. The hospital anxiety and depression (HAD) scale, which consists of 14 questions, was used to assess the degree of anxiety (HAD-A) and depression (HAD-D). The mean age of the patients was 69.5 +/- 10.8 year (SD), and the duration of LTOT was 944 +/- 739 days. The mean values were 0.77 +/- 0.45 L for FEV1.0, 57.7 +/- 7.4 Torr for PaO2, and 47.4 +/- 8.1 Torr for PaCO2. FEV1.0 was correlated with PaCO2(r = -0.548, p < 0.0001), but it was not correlated with PaO2. High correlation was noted between HAD-A and HAD-D (r = 0.693, P < 0.0001), whereas correlation was not noted between HAD and the physiologic state. VAS was significantly correlated with FEV1.0 (r = 0.320, p < 0.05), as well as with HAD-A (r = 0.358, p < 0.01) and HAD-D (r = 0.444, p < 0.01). Dyspnea ratings were found to be influenced by anxiety and the depression state, and also by the degree of flow limitation in patients with COPD during LTOT. In contrast, the physiologic state scarcely influenced the anxiety and depression state. Thus, psychotherapy may play an important role in the reduction of dyspnea sensation, which is an important determinant of quality of life.
Parenteral strobilation of Echinococcus multilocularis was observed in acid (severe combined immuno-deficient) mice after intracerebral, subcutaneous and intraperitoneal inoculation with protoscoleces. Evaginated protoscoleces and segmented worms were obtained at the inoculated sites. Most worms recovered from peritoneal cavity of scid mice were encapsulated by connective tissue and granulocytes but showed a maximum of 3 proglottids, elongation of genital primordia and vesiculation. Viability of worms recovered from the subcutaneous tissue and peritoneal cavity of scid mice were higher (69.1-91.4%) than those from the immunologically normal C.B-17 (4.0-48.0%) control mice. However, viabilities of worms from the cerebrum of both scid and C.B-17 were almost the same (87.7-94.4%). Worms recovered from scid mice showed further development of reproductive organs when transplanted into the small intestine of prednisolone treated golden hamster. These findings suggest that the parenteral milieu of scid mice allows adult development of E. multilocularis protoscoleces.
The accuracy and validity of a body box system which was developed for the measurement of airway and chest wall impedance in small animals such as canines was evaluated. Input impedance was calibrated using a resistance tube and the mouth flow sensing system was designed to be as symmetrical as possible such that the minimal common mode rejection ratio (CMRR) from 10 to 40 Hz was greater than 60 dB. The validity of this system using the resistance tube and inertant models indicated that the average error ratio for the input impedance and for the flow transfer function between the mouth and chest flow was within 3 and 0.5%, respectively. The location of the box pressure port near to the oscillatory flow inlet was shown to potentially give rise to errors in the measurement of the flow transfer factor due to the direct effects of the inflow. A distance of 60 cm was adopted in the present system, which proved to be sufficient to avoid this effect. It was concluded that the body box system which is described for small animals in the present study is appropriate for obtaining separate and accurate airway and tissue impedance data.
We measured the chest flow 0.1 s after the onset of the inspiratory phase (V0.1) in patients with chronic pulmonary emphysema (CPE: n = 5), interstitial pneumonitis (IP: n = 5) and normal subjects (Nor: n = 5). The subjects sat in a body box and breathed air from outside of the body box. V0.1 was measured during rest and during maximal breathing (V0.1-rest, V0.1-max) and then these results were compared with P0.1 (P0.1 rest, P0.1-max) values. V0.1-rest was not significantly different between the three groups (Nor: 0.25 +/- 0.10, CPE: 0.27 +/- 0.06, IP: 0.26 +/- 0.06, l/s), whereas the P0.1-rest in IP patients was significantly greater than in normal subjects (Nor: 1.98 +/- 0.61, CPE: 3.00 +/- 0.80, IP: 3.60 +/- 0.68 hPa; P < 0.05 compared with normal). The V0.1-max in CPE and IP patients was significantly lower than in normal subjects (Nor: 3.66 +/- 1.16, CPE: 0.82 +/- 0.25, IP: 1.02 +/- 0.21 l/s, P < 0.05 compared with normal subjects (Nor: 3.66 +/- 1.16, CPE: 0.82 +/- 0.25, IP: 1.02 +/- 0.21 l/s, P < 0.05 compared with normal), whereas P0.1-max in IP patients was not significantly different with in normal subjects (Nor: 33.2 +/- 10.2, CPE: 9.8 +/- 3.7, IP: 19.5 +/- 3.4 hPa, P < 0.05 compared with normal, P < 0.05 compared with CPE). A simulation of the influence of the mechanical properties of the respiratory system on V0.1 and P0.1 using the Runge-Kutta method suggested that V0.1 was negatively affected by airway resistance but positively affected by chest wall and lung compliance. In contrast, the influence of respiratory mechanics on P0.1 was much less than on the V0.1, except for highly decreased lung compliance. In CPE patients, it was suspected that mechanical disorders might not simply be the determining factors of V0.1-max, but that limitations of the neuro-muscular drive due to chest wall deformity may also play a definitive role in the smaller V0.1-max. In contrast, it may be inferred that IP patients had to exert greater inspiratory effort as compared with the other two groups in order to maintain a similar V0.1-rest because of the increased airway resistance and decreased tissue compliance; thus these abnormal mechanical properties suppress the increase in the V0.1-max. It may be concluded that V0.1 is a good index of chest wall acceleration, which is determined by both the neuro-muscular drive and the mechanics of the respiratory system.
The gray red-backed vole Clethrionomys rufocanus bedfordiae and laboratory mice were fed eggs of Taenia mustelae via a stomach tube. Fully developed metacestodes were recovered from the voles fed the eggs at 25 days postinfection; voles were considered to be more suitable intermediate hosts for T. mustelae than laboratory mice. The prepatent period for the metacestodes from voles was shorter (16 days) in the mink than previously reported. A field survey was performed on hepatic cestodes of small mammals in Hokkaido, Japan in August 1993. We found T. mustelae metacestodes from C. rufocanus bedfordiae, representing a new host record.
Cystic hydatidosis (CH) caused by Echinococcus granulosus is an important zoonosis worldwide. Several serodiagnostic and ultrasound tests are currently used for screening asymptomatic CH. The sensitivity of the serodiagnostic tests has been demonstrated by several groups to be lower than ultrasonography (US). To explain the mechanism of the difference in sensitivity, a large-scale US survey combined with an IgG4-enzyme-linked immunosorbent assay test was conducted in Uruguay. Our results suggest that certain cyst images, e.g., multivesicular cysts, may be closely associated with a high antibody response regardless of the cyst size, whereas other hydatid lesions, e.g., solid images with/without rolled parasite membranes, have lower antibody responses with a close relationship to cyst size. Seropositivity of subjects who had been treated surgically for removal of hydatid cysts in the last 5 yr was closest to that of actual CH patients, albeit free from CH by US. These findings are important for the proper use of serodiagnostic tests and US for community-based epidemiological studies.
Superior laryngeal nerve (SLN) stimulation during expiration prolongs the respiratory cycle in decerebrate, vagotomized and paralysed cats. In a few animals, however, the cycle can be terminated prematurely by the same stimulus. We developed a mathematical model of the respiratory neural network to stimulate these responses. The model contained inspiratory decrementing (I-DEC), and augmenting (I-AUG) and expiratory decrementing (E-DEC), and augmenting (E-AUG) neurones. Connections were based on published findings. SLN stimulation during late expiration prolonged the cycle when it was assumed to excite principally E-DEC neurones, whereas it terminated the cycle prematurely when it was assumed to excite both I-DEC and E-DEC neurones. Therefore, phase-resetting depends on the differential strength of afferent connections on the network's elements.
The intraspecific variation of four laboratory-reared isolates of Taenia taeniaformis the SRN and KRN isolates from Norway rats, Rattus norvegicus, captured in Japan and Malaysia, respectively; the BMM isolated from a house mouse, Mus musculus, captured in Belgium; and the ACR isolate from a gray red-backed vole, Clethrionomys rufocanus bedfordiae, captured in Japan was examined by various criteria. Eggs of each of the four isolates were orally inoculated into several species of intermediate host. They were most infective to the rodent species from which the original metacestode of each isolate had been isolated in the field, and only the ACR isolate was infective to the gray red-backed vole. Although little difference was found between the SRN, KRN, and BMM isolates by the other criteria, including the morphology of rostellar hooks, the protein composition of the metacestode, and restriction endonuclease analysis of DNA, the ACR isolate was clearly different from the others. It was considered that the ACR isolate was independent as a strain distinct from the other three isolates.
A mathematical model has been developed that includes sensations of breathlessness and a dynamic CO2 respiratory controller. Breathing sensations, which are represented as a discomfort index, are assumed to depend on arterial PCO2 level, automatic and wilful motor commands and mechanoreceptor feedback. Wilful control is assumed to arise from cortical centres of the brain and is independent of the reflex control system. The bulbopontine respiratory controller produces the automatic motor command, which is determined by chemical and mechanical feedback. Simulations demonstrate how the controller output and breathing sensations change when wilful motor commands disturb spontaneous breathing. Simulations include isocapnic hyper- and hypoventilation and deliberate hypoventilation during CO2 rebreathing. Simulations are compared with experimental data from human subjects. Simulations predict that the discomfort index intensifies when ventilation is either voluntarily raised or lowered from the optimal level; and discomfort is greater when ventilation is lowered than when it is raised at a given level of PCO2. The simulated results agree with those obtained experimentally. The simulations suggest that respiratory drive integration may depend not only on the direct effects of chemical and mechanical feedback, but also on the perceptual consequences of these stimuli.
The technique of isoenzyme electrophoresis was applied to Japanese wild populations of Taenia taeniaeformis (isolated from Norway rats) and three laboratory reared isolates (KRN isolated from a Malaysian Norway rat, BMM from a Belgian house mouse and ACR from a Japanese gray red-backed vole). The average heterozygosities of Japanese wild populations were fairly small and total genetic variability was 0.0499. The genetic make-up of T. taeniaeformis in Norway rats was rather uniform in the whole of Japan. In KRN isolate, each of all 10 loci examined possessed the allele which was predominant in Japanese wild populations. Similarly, each of 9 loci in BMM isolate possessed the same alleles, but one of 2 alleles at HK locus was different from that in the others. T. taeniaeformis parasitizing house mice and rats were considered to be genetically closely related to each other. In ACR isolate, 7 out of 10 loci possessed different alleles from those in the other populations. It was considered that ACR isolate was genetically distant and its phylogenetic origin in Japan should be different from worms parasitizing Norway rats.
To investigate the effects of aging on pulmonary mechanical properties in mice, we devised a new experimental apparatus to measure the respiratory impedance of excised lungs in mice and examined age-related changes in both static and dynamic properties. In an accelerated senescence-resistant strain of mice, SAMR1 (Takeda, T., Y. Fukuchi, Y. Uejima, K. Teramoto, T. Oka and H. Orino, J. Am. Geriatr. Soc. 39: 911-919, 1991), ranging from 3 to 24 months of age, static compliance (Cst) as well as total lung capacity increased significantly with age, whereas specific compliance and the K value, as determined by exponential analysis, showed no significant change. In the dynamic study, dynamic compliance (Cdyn) increased significantly with age, whereas the frequency dependence of Cdyn (Cdyn/Cst) did not vary with age. From these results we concluded that lung elasticity, normalized to lung volume, remained constant with age and that the effects of aging on pulmonary mechanics might be solely derived from increases in lung volume in the SAMR1 strain of mice.
DNA from T. taeniaeformis digested with the restriction endonuclease was hybridized with digoxigenated oligonucleotide probe (CAC)5. Metacestode and adult showed same clear multibanding patterns, which were characteristic of multilocus DNA fingerprinting. The fingerprinting patterns were quite different from those of the rodent hosts. Genetic variations in 4 laboratory-reared isolates of T. taeniaeformis, including 3 isolates which have been reported to be indistinguishable by infectivity, morphology and protein composition of metacestode, were investigated using this technique. Each of the 4 isolates exhibited isolate-specific fingerprinting patterns and were easily distinguished from one another, thus it was considered that (CAC)5 was a highly resolvable and informative probe for cestodes. However, it was also indicated that (CAC)5 was so sensitive that applying fingerprinting with (CAC)5 to taxonomical or phylogenetic analysis was limited where habitat of the host was restricted to the small area. In comparison to fingerprinting with 32P-labeled (CAC)5, fingerprinting with digoxigenated (CAC)5 represented more and sharper bands. It was considered that a digoxigenated probe was more useful for genetic analysis of cestodes.
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Antibody response to Syphacia obvelata infection was observed in AKR/J mice by ELISA. Experimental infection with the pinworm eggs showed the presence of specific IgG against S. obvelata somatic antigens at 12 days postinfection, and that it increased steadily thereafter. Sera of S. obvelata-infected mice showed cross-reactivity with somatic antigens of other Syphacia species such as S. mesocriceti and S. muris, but not with Aspiculuris asiatica. Western blotting of S. obvelata antigen with sera of S. obvelata-infected mice showed a corresponding increase in the number of bands during the course of infection. Infected mice showed significantly higher antibody production to sheep red blood cells than the uninfected control mice. Thus, S. obvelata infection is shown to alter the humoral response to nonparasitic antigenic stimuli. These observations indicate that infection by helminths, which apparently do not produce clinical symptoms, might modulate the immune system of the host and, therefore, affect experimental results.
Twelve species of nematodes comprising 9 genera were recovered from the gastrointestinal tract of 2 Euphractus sexcinctus and 2 Dasypus novemcinctus captured in the Department of San Pedro, Paraguay. All armadillos were infected with 1 or more species of nematode. The following nematodes were recovered: Mazzia mazzia, Spirura guianensis, Trichohelix tuberculata, Ancylostoma sp., Moennigia complexus, Moennigia pintoi, Ascaris dasypodina, Cruzia tentaculata, Aspidodera fasciata, Aspidodera scoleciformis, Aspidodera esperanzae n. sp., and Heterakinae gen. sp. This report describes a new species of the Aspidodera nematode, Aspidodera esperanzae n. sp., the first species to be reported bearing cephalic cordons made up of 7 longitudinal loops in the subfamily of Aspidoderinae. This study also documents a new host record for S. guianensis and shows a new geographical distribution in Paraguay for M. mazzia, S. guianensis, T. tuberculata, M. complexus, and M. pintoi.