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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 505 records · Page 28Linked to original sources
PubMed1995

Unimpaired clearance of Mycobacterium bovis BCG infection in selectively T-cell anergic TCR-V beta 8.2 transgenic mice.

The anergy induced in mice with staphylococcal enterotoxin B (SEB) has been shown to involve selective unresponsiveness in cytokine expression. While interleukin-2 (IL-2), IL-3 and IL-4 mRNA levels are substantially reduced in anergic T cells upon restimulation with SEB, mRNA for interferon-gamma (IFN-gamma) is expressed normally. On the other hand, infection with Nippostrongylus brasiliensis is known to break an established T-cell anergy. This knowledge prompted us to examine the effect of infection with an intracellular microbe, bacillus Calmett-Guérin (BCG), on the expression of anergy induced with SEB. We have demonstrated that while the SEB-induced anergy was not abrogated by BCG infection, the V beta 8.2 transgenic mice, in which almost all T cells were anergized with SEB, were capable of developing the effective acquired protective immunity, possibly through the preserved capacity to induce IFN-gamma leading to induction of nitric oxide synthase.

Animals↗
PubMed1995

[Ventricular septal defect with severe pulmonary hypertension: the role of open biopsy in determination of operative indication: a case report].

A 51-year-old man having ventricular septal defect with severe pulmonary hypertension is reported. Operative indication that is denied was finally decided by open lung biopsy. He had pulmonary arterial pressure of 120/42 (70) mmHg. The ratio of pulmonary to systemic systolic pressure was 0.91, the ratio Of pulmonary to systemic flow was 1.26, the ratio of pulmonary to systemic vascular resistance was 0.34, and pulmonary vascular resistance was 14.2 unit x m2. For the reason of difficulty, in determination of operative indication through hemodynamic study, he received open lung biopsy. Histological assessment from biopsy specimen revealed severe occlusive pulmonary vascular disease exhibiting grade IV on the Heath Edwards classification. Open lung biopsy occasionally be selected in case with difficult determination of operative indication in severe pulmonary hypertension is a useful tool.

Biopsy↗
PubMed1995

Vitreous videography using the scanning laser ophthalmoscope.

To establish the method of vitreous videography using the scanning laser ophthalmoscope, we observed the vitreous in patients with age- or disease-related vitreous changes. We compared the results using four laser wavelengths. The detailed structures of the posterior vitreous cortex, a premacular defect, and a prepapillary glial ring were clearly shown under direct laser illumination. A short wavelength laser was found to be superior to a long wavelength laser for observing the posterior vitreous cortex. Vitreous opacities were clearly shown as dark spots under retroillumination using any of the four laser wavelengths. In vivo visualization of the vitreous was achieved using this new technique, which is superior to conventional biomicroscopy because of its monochromatic laser delivery system and confocal light detection capacity.

Adolescent↗
PubMed1994

Cloning of a cDNA encoding human ALDH7, a new member of the aldehyde dehydrogenase family.

Aldehyde dehydrogenases (ALDH; EC 1.2.1.3) are a family of isozymes which have been suggested to play a major role in the detoxification of aldehydes generated by alcohol metabolism and lipid peroxidation. Five non-allelic ALDH genes, encoding the ALDH1, 2, 3, 5 and 6 isozymes, have previously been identified and cloned in our laboratory. In this paper, we report the cloning and sequencing of a cDNA encoding a new human ALDH (ALDH7). Degenerate oligodeoxyribonucleotides derived from conserved regions of known ALDH cDNAs amplified a 408-bp product from human kidney total RNA by the reverse transcription-polymerase chain reaction (RT-PCR) procedures [Hsu et al., J. Biol. Chem. 266 (1992) 3030-3037]. This PCR product was subcloned, selected and used as a probe to screen a human kidney cDNA library. The full-length human kidney cDNA (ALDH7) is 2791 bp in length and contains an open reading frame encoding 468 amino acids (aa). The deduced sequence of ALDH7 is longer than that of the human stomach ALDH3 by 15 aa at the C terminus. The degree of identity between the two isozymes is 52% with a positional alignment of 453 aa. Northern blot analysis demonstrated that lung is another major tissue expressing ALDH7.

Aldehyde Dehydrogenase↗
PubMed1994

Synaptotagmin I is essential for Ca(2+)-independent release of neurotransmitter induced by alpha-latrotoxin.

alpha-Latrotoxin causes massive release of norepinephrine from clonal rat pheochromocytoma PC12 cells, in the absence of external Ca2+, by an unknown mechanism. The effect almost disappeared in PC12 variant cells deficient in synaptotagmin I, a synaptic vesicle protein, and was rescued by transfecting the synaptotagmin I gene. These results indicate that synaptotagmin I is essential for the Ca(2+)-independent action of alpha-latrotoxin in PC12 cells.

Animals↗
PubMed1994

Cloning and characterization of the gene encoding mouse mitochondrial aldehyde dehydrogenase.

The mitochondrial (mt) aldehyde dehydrogenase (ALDH2) in liver has been considered to play a major role in the detoxification of alcohol in humans. Using the human ALDH2 cDNA and synthetic oligodeoxyribonucleotides (oligos) as probes, the mouse ALDH2 (mALDH2) gene was isolated and characterized. Nucleotide (nt) sequence analysis revealed an open reading frame (ORF) of 1560 bp encoding a protein of 519 amino acid (aa) residues. The gene is composed of 13 exons and 12 introns and spans approx. 26 kb of the mouse genome. The deduced aa sequence, when compared to the mtALDH2 of human, rat, horse and bovine, revealed 95.8, 99.0, 95.6 and 93.6% aa identity, respectively. Primer extension and rapid amplification of cDNA ends (RACE) experiments showed that the transcription start point (tsp) was 105 bp upstream from the start codon. The promoter region of mALDH2 is devoid of a TATA consensus sequence motif, but putative regulatory elements, including a CAAT box, Sp1-binding site and glucocorticoid-response element (GRE), are present in the promoter region. Northern blot hybridization demonstrated the existence of a high level of mALDH2 mRNA in mouse liver and a low level in mouse kidney.

Aldehyde Dehydrogenase↗
PubMed1994

Morphology and synaptic connections of slowly adapting periodontal afferent terminals in the trigeminal subnuclei principalis and oralis of the cat.

Previous studies suggest that sensory information from primary afferent fibers is processed in a distinct manner in the individual subnuclei of trigeminal sensory nuclear complex. The present study has addressed this issue by using intra-axonal labeling with horseradish peroxidase to examine the ultrastructure and synaptic organization of axon terminals from slowly adapting (SA) periodontal afferents in the ventral subdivision (Vpv) of principalis and the rostro-dorsomedial part (Vo.r) of oralis. Our observations are based on complete or near-complete reconstructions of 139 synaptic boutons in Vpv and 105 in Vo.r. All the labeled boutons contained clear, spherical, synaptic vesicles and were presynaptic to unlabeled dendrites, and they were frequently postsynaptic to unlabeled axon terminals containing pleomorphic synaptic vesicles (P-endings). The P-endings frequently formed axodendritic synapses on dendrites which received axodendritic synapses from labeled boutons (synaptic triads). On the basis of the number of contacts, synaptic arrangements associated with the labeled boutons could be subgrouped into simple (one or two contacts), intermediate (three or four contacts), and complex (five or more contacts) types. The labeled boutons varied from round to elongated forms with smooth to more irregular or scalloped contours. The boutons with scalloped contour were much more frequent in the complex type. The boutons of the intermediate type were significantly smaller than the complex type and larger than the simple type. The SA periodontal afferent terminals participated in each type of synaptic arrangements in Vpv, but were mostly of the simple type in Vo.r. The size of labeled boutons was significantly larger in Vpv than in Vo.r. The total number of axodendritic and axoaxonic contacts per labeled bouton was significantly higher in Vpv than in Vo.r. Another difference was the more frequent occurrence of synaptic triads in Vpv than in Vo.r. These observations provide evidence that sensory information from primary afferent fibers is processed in a different manner in the two subnuclei.

Adaptation, Physiological↗
PubMed1994

Two major types of premotoneurons in the feline trigeminal nucleus oralis as demonstrated by intracellular staining with horseradish peroxidase.

Previous studies suggest that neurons in the dorsomedial subdivisions of trigeminal nucleus oralis (Vo) may contribute to reflex control of jaw movements and to modulation of sensory information. The present study has addressed this possibility by the use of intracellular staining with horseradish peroxidase of physiologically identified neurons in Vo to examine functional and morphological properties of these neurons. Of 14 labeled neurons, eight had axon collaterals terminating exclusively in the dorsolateral subdivision of the trigeminal motor nucleus (DL neurons) and four in its ventromedial subdivision (VM neurons); axon collaterals of two neurons were not traced. Both groups of neurons sent terminal arbors into other nuclei of the lower brainstem. The DL neurons were distinguishable from the VM neurons in their receptive field (RF) location, neuronal position, somadendritic architecture, and projections to other brainstem nuclei. All neurons, except for two that were exclusively activated by noxious stimuli applied to the tongue, were responsive to light mechanical stimulation of peri- and intraoral structures. The RFs of the DL neurons were located in more posterior oral structures than those of the VM neurons. The RF of nearly all low-threshold DL neurons was located in the maxillary region, and that of the VM neurons, in contrast, involved the mandibular region. The VM neurons were located medial or ventral to the DL neurons. The soma size of the VM neurons was significantly larger than that of the DL neurons. Dendritic arbors of both groups could be separated into medial and lateral components. The ratio of the dendritic transverse areas in the medial vs. lateral component was significantly higher in the VM neurons than in the DL neurons. The DL neurons also issued collaterals that terminated in larger brainstem areas than those of the VM neurons. These observations provide new evidence on the morphological and functional properties of Vo neurons that contribute to reflex control of jaw and facial movements and modulation of sensory information.

Animals↗
PubMed1994

c-Fos induction in the rat spinal dorsal horn partially deafferented by dorsal rhizotomy.

The 4th and 5th segments of the lumbar (the L4 and L5) dorsal horn receive primary input from the sciatic receptive fields through the L4 and L5 dorsal roots. Noxious stimulation of the hindpaw with formalin induces c-Fos in neurons in superficial laminae (I and II) of these dorsal horn segments. Rhizotomy of the L5 dorsal root 2 days before stimulation resulted in a marked reduction in the number of neurons with c-Fos protein-like immunoreactivity (fos-neurons). At 3 weeks after the L5 rhizotomy, the number of fos-neurons in laminae I and II significantly increased compared to that at 2 days post-rhizotomy. This result indicates that chronic partial deafferentation by dorsal rhizotomy increases responsiveness of superficial dorsal horn neurons to spared primary input.

Animals↗
PubMed1994

Differential effects of gangliosides on Ig production and proliferation by human B cells.

The effects of gangliosides on human B-cell responses were studied. Of various gangliosides tested, only GM2 and GM3 inhibited production of IgG subclasses and IgM, but not IgA subclasses, and thymidine uptake by human B cells stimulated with SAC plus interleukin-2 (IL-2). In contrast, GM1, GD1a, GD1b, GD3, GT1b, and GQ1b were without effects. GM2- and GM3-induced inhibition were specific, because each was blocked by a corresponding antibody. Of various cytokines tested, tumor necrosis factor-alpha (TNF-alpha) alone counteracted GM2- and GM3-induced inhibitions of Ig production and thymidine uptake, whereas other cytokines including IL-1 beta, IL-3, IL-5, IL-6, and interferon-gamma each failed to do so. Moreover, anti-TNF-alpha antibody, but not control IgG, blocked the counteraction of inhibition by TNF-alpha. GM2 and GM3 each inhibited Ig production, thymidine uptake, and TNF-alpha production by surface IgG1+ (slG1+), sIgG2+, sIgG3+, sIgG4+, and sIgM+ B cells without affecting IL-2 binding or TNF-alpha binding to B cells, but had no such inhibitory effects on sIgA1+ or sIgA2+ B cells. These findings indicate that GM2 and GM3 inhibit Ig production and thymidine uptake by human sIgG1+, sIgG2+, sIgG3+, sIgG4+, and sIgM+ B cells by inhibiting endogenous TNF-alpha production.

Antibody Formation↗
PubMed1994

Expression of multidrug resistance-associated protein (MRP) in anaplastic carcinoma of the thyroid.

Although the incidence is very low, the prognosis of anaplastic carcinoma of the thyroid is very poor regardless of the results of various therapeutic trials. We found that the mechanism of anti-cancer drug resistance in anaplastic carcinoma of the thyroid was not explicable only in terms of expression of the mdr1 and its gene product, P-glycoprotein. Therefore, expression of multidrug resistance-associated protein (MRP) mRNA was examined in 11 anaplastic thyroid carcinomas and eight anaplastic thyroid carcinoma cell lines. High MRP mRNA expression was recognized in 7/11 and 8/8, respectively. Our results may contribute to elucidation of the mechanism of anti-cancer drug resistance in this neoplasm.

Base Sequence↗
PubMed1994

Differential effect of growth hormone and insulin-like growth factor-I, insulin-like growth factor-II, and insulin on Ig production and growth in human plasma cells.

The effect of human growth hormone (GH) and insulin-like growth factor-I (IGF-I), IGF-II, and insulin on human plasma cell responses was studied. GH enhanced Ig production and thymidine uptake in the human plasma cell lines, IM-9 and AF-10. IGF-I, but not IGF-II or insulin, also enhanced Ig production and proliferation in them. However, enhancement by GH was not mediated by IGF-I, because enhancement was blocked by anti-GH antibody (Ab), but not by Ab to IGF-I or IGF-I receptor. Conversely, the enhancement by IGF-I was blocked by either Ab to IGF-I or IGF-I receptor, but not by anti-GH Ab. GH and IGF-I also enhanced production of IgG1, IgG2, IgG3, IgG4, IgA1, IgA2, and IgM and thymidine uptake in PCA-1+ plasma cells generated in vitro. Again, enhancement by GH was specifically blocked by anti-GH Ab, whereas enhancement by IGF-I was specifically blocked by either Ab to IGF-I or IGF-I receptor. These results indicate that GH and IGF-I may play important roles in plasma cell responses.

Cell Division↗
PubMed1994

[Preliminary clinical applications of asymmetric screen-film systems in chest radiography].

The physical imaging properties of asymmetric systems and a conventional system were evaluated by measuring characteristic curves, resolution properties and noise Wiener spectra. The potential clinical application of asymmetric screen-film systems was studied by evaluating the visibility of the anatomical structures and various types of abnormalities in comparison with those of a conventional screen-film system. The asymmetric systems showed a wider dynamic range than the conventional system. The resolution properties of asymmetric systems depend on the combination of front and back screens used. Chest radiographs obtained with asymmetric systems improved the visibility of the mediastinal area. The visibility of the lung field in the asymmetric systems was slightly inferior to that with the conventional system when the same tube potential was used. However, the image quality and visibility of various abnormalities showed greater improvement with the asymmetric systems when a lower tube potential was applied. We conclude that the selection of radiographic techniques and combination of screens are important for the clinical use of asymmetric systems.

Humans↗
PubMed1994

IFN-gamma induces IL-12 mRNA expression by a murine macrophage cell line, J774.

Interleukin (IL)-12 is a logical candidate for participation in the differentiation of T helper (Th) 1 cells. IL-12 is produced by macrophages and B cells and induces the production of interferon (IFN)-gamma from Th1 cells and NK cells. In this study, we show that the IFN-gamma itself is capable of inducing IL-12 mRNA expression in murine macrophage cell line J774. The mRNA was apparent by 12h after IFN-gamma treatment, although maximal induction required 36 to 48h. Furthermore, we investigated the signal transduction mechanism responsible for the mRNA expression. The IFN-gamma-inducible IL-12 mRNA was blocked by two protein tyrosine kinase (PTK) inhibitors, genistein and herbimycin A, suggesting that PTK is involved in the IFN-gamma-inducible IL-12 mRNA expression.

Animals↗
PubMed1994

Central terminations of low-threshold mechanoreceptive afferents in the trigeminal nuclei interpolaris and caudalis of the cat.

Previous studies indicate that vibrissa, nonvibrissa, guard hair, hairy skin, and periodontal ligament afferents give rise to morphologically distinct terminal arbors in the trigeminal nuclei principalis (Vp) and oralis (Vo) in the cat. The present study describes the extent to which morphological and functional relationships exist in the nuclei interpolaris (Vi) and caudalis (Vc). Twenty-two fibers were physiologically characterized and stained by intra-axonal HRP injection techniques. The fast adapting (FA) vibrissa (VF) afferents gave rise to compact and circumscribed arbors in Vi and Vc. These tended to be larger in Vc than in Vi. The slowly adapting (SA) vibrissa (VS) afferents in Vi and Vc had more widespread and larger arbors than those of the VF afferents. The VS arbors in Vc tended to be larger and less circular than those in Vi. Guard hair (GH) afferents gave rise to circumscribed arbors in both nuclei, but those in Vc tended to have larger and more circular arbors than those in Vi. Down hair (DH) afferents gave rise to small, circumscribed arbors or a few distinct patches of boutons within a small area in Vi; arbors in Vc were less extensive and "stringy." Unlike other afferents, DH arbors were larger in Vi than in Vc, but smaller than those of GH afferents in either nuclei. The SA hairy skin (SS) afferents had arbors that were widespread with a few distinct patches of boutons; the arbors in Vc were larger than those in Vi. The arbors of SS afferents were smaller than those of VS and GH afferents in both nuclei. Like GH afferents, FA periodontal ligament (PF) afferents gave rise to large and circumscribed arbors in Vi, although the arbors in Vc were smaller and less dense. The present study demonstrated significant functional and morphological relationships for primary afferents in Vi and Vc, thus suggesting that sensory information from each of the distinct fiber or functional classes is processed in a characteristic manner in the individual nuclei.

Afferent Pathways↗