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Biomedical subjects

K Takagi

Publications and source records attributed to K Takagi.

At least 127 records · Page 7Linked to original sources

[Progressive paralysis of divergence in an adult with midbrain angioma].

A 37-year-old woman was admitted to the hospital with the complaint of progressive horizontal diplopia of six years' duration when viewing distant objects. On admission she had a slight left convergent strabismus. Homonymous diplopia was present beyond 50 cm and increased on distance fixation. Both eyes were fully mobile in the horizontal plane with a mild decrease in the velocity of horizontal eye movement to the left, and slight impairment of upward eye movement. The left eye did not fully adduct during convergence. The right pupil was slightly larger than the left. Prism cover test showed 6 delta esophoria at 30 cm and 14 delta esophoria at 5 m. The Hess chart showed a convergent deviation. MRI revealed a small right-side paramedian lesion of the midbrain tegmentum lying ventral to the aqueduct of Sylvius, at the level between the superior colliculi and the intercollicular area. A venous angioma with arteriovenous shunts in the right midbrain was diagnosed by angiography. We suggest that lesions that damage the divergence neurons in the tegmentum of the midbrain and also interrupt the supranuclear fibers having an inhibitory effect on the convergence neurons may produce homonymous diplopia on distant fixation combined with the esotropia.

Adult↗

The hypervariable region 1 protein of hepatitis C virus broadly reactive with sera of patients with chronic hepatitis C has a similar amino acid sequence with the consensus sequence.

Hypervariable region 1 (HVR1) proteins of hepatitis C virus (HCV) have been reported to react broadly with sera of patients with HCV infection. However, the variability of the broad reactivity of individual HVR1 proteins has not been elucidated. We assessed the reactivity of 25 different HVR1 proteins (genotype 1b) with sera of 81 patients with HCV infection (genotype 1b) by Western blot. HVR1 proteins reacted with 2-60 sera. The number of sera reactive with each HVR1 protein significantly correlated with the number of amino acid residues identical to the consensus sequence defined by Puntoriero et al. (G. Puntoriero, A. Lahm, S. Zucchelli, B. B. Ercole, R. Tafi, M. Penzzanera, M. U. Mondelli, R. Cortese, A. Tramontano, G. Galfre', and A. Nicosia. 1998. EMBO J. 17, 3521-3533. ) (r = 0.561, P < 0.005). The most widely reactive HVR1 protein, 12-22, had a sequence similar to the consensus sequence. The peptide with C-terminal 13-amino-acids sequence of HVR1 protein 12-22 (NH2-CSFTSLFTPGPSQK) was injected into rabbits as an immunogen. The rabbit immune sera reacted with 9 of 25 HVR1 proteins of genotype 1b including HVR1 protein 12-22 and with 3 of 12 proteins of genotype 2a. These results indicate that the HVR1 protein broadly reactive with patients' sera has a sequence similar to the consensus sequence, can induce broadly reactive sera, and could be one of the candidate immunogens in a prophylactic vaccine against HCV.

Amino Acid Sequence↗

Role of ecto-kinase in phorbol ester-enhanced growth hormone-binding protein release from human IM-9 cells.

Previously we reported that a phorbol ester, phorbol 12, 13-dibutyrate (PDBu), increased the release of human growth hormone-binding protein (hGH-BP) in IM-9 cells, and that this phorbol ester-enhanced release was mediated by protein kinase Ca (PKCalpha). In the present study, the mechanisms of the phorbol ester-enhanced hGH-BP release were further investigated. Treatment of IM-9 cells with PDBu did not increase hGH-BPs (55-60 kDa) in the intracellular soluble fraction. When the cells were treated with trypsin to remove human growth hormone receptors (hGHRs) on the cell surface after stimulation, no hGH-BPs were detected in the culture supernatants, nor did treatment with bafilomycin A1 or chloroquine affect the PDBu-enhanced hGH-BP release. These results suggest that hGH-BPs released by PDBu stimulation are derived from cell surface hGHRs and not generated within the cells. Protein kinase inhibitors with broad specificities, K-252a and K-252b, inhibited the PDBu-enhanced release with almost the same dose-dependency, although only a trace amount of K-252b was incorporated into IM-9 cells than K-252a, suggesting that K-252b probably inhibits an ecto-kinase extracellularly. PDBu actually enhanced the phosphorylation of several extracellular proteins, and this enhanced phosphorylation was completely inhibited by K-252b treatment. Moreover, the PKCalpha-specific inhibitor bisindolylmaleimide III which inhibits PDBu enhanced hGH-BP release inhibited the PDBu-enhanced phosphorylation of extracellular proteins. On the other hand, the impermeable PKC inhibitor PKC inhibitor peptide 19-31 did not inhibit PDBu-enhanced release, suggesting that the target PKCalpha for PDBu is not present on the extracellular surface. Taken together, these results suggest that, in addition to intracellular PKCalpha, activation of an undefined ecto-kinase may also be involved in the PDBu-enhanced hGH-BP release.

Carbazoles↗

Tetracyclines reduce Na+/K+ pump capacity in Calu-3 human airway cells.

We studied the effect of tetracyclines on the Na+/K+ pump activity in Calu-3, a human airway cell line. To estimate Na+/K+ pump capacity on the basolateral membrane, an ouabain-sensitive component of the short-circuit current (Isc) was measured in the presence of nystatin, an ionophore of Na+. The application of ouabain (1 mM) to the basolateral solution completely inhibited the Isc generated by adding nystatin (50 microM) to the apical solution. Tetracycline (TC), minocycline (MC), or demethylchlortetracycline (DC) at 0.5 mM applied to the apical but not to the basolateral solution also decreased the nystatin-induced Isc. Neither phlorizin- nor diphenylamine-2-carboxylic acid-sensitive Isc was affected by TC, MC, or DC. These results indicate that tetracyclines may permeate only through the apical membrane with the result that the Na+/K+ pump's capacity for Na+ extrusion should be suppressed without a decrease in Cl- transport.

Anti-Bacterial Agents↗

Biochemical and electrochemical characterization of quinohemoprotein amine dehydrogenase from Paracoccus denitrificans.

A new quinohemoprotein amine dehydrogenase from Paracoccus denitrificans IFO 12442 was isolated and characterized in views of biochemistry and electrochemistry. This enzyme exists in periplasm and catalyzes the oxidative deamination of primary aliphatic and aromatic amines. n-Butylamine or benzylamine as a carbon and energy source strongly induces the expression of the enzyme. Carbonyl reagents inhibit the enzyme activity irreversibly. This enzyme is a heterodimer constituted of alpha and beta subunits with the molecular mass of 59.5 and 36.5 kDa, respectively. UV-vis and EPR spectroscopy, and the quinone-dependent redox cycling and heme-dependent peroxidative stains of SDS-PAGE bands revealed that the alpha subunit contains one quinonoid cofactor and one heme c per molecule, while the beta subunit has no prosthetic group. The redox potential of the heme c moiety was determined to be 0.192 V vs NHE at pH 7.0 by a mediator-assisted continuous-flow column electrolytic spectroelectrochemical technique. The analysis of the substrate titration curve allowed the evaluation of the redox potential of the quinone/semiquinone and semiquinone/quinol redox couples as 0.19 and 0.11 V, respectively.

Dithionite↗

Intracranial dural arteriovenous fistula (DAVF) presenting progressive dementia and parkinsonism.

We studied three patients with dural arteriovenous fistula (DAVF). Major symptoms were progressive dementia and parkinsonism, both of which progressed in step-wise fashion. Two of the three patients showed diffuse cerebral white matter lesions on brain CT and MRI. Progressive dementia and parkinsonism in our patients could be caused by diffuse cerebral parenchymal disturbance: impaired cerebral circulation due to severe venous hypertension. DAVF is important for the differential diagnosis in patients with progressive dementia and parkinsonism.

Aged↗

Electrochemical study of reversible hydrogenase reaction of Desulfovibrio vulgaris cells with methyl viologen as an electron carrier.

An electrode modified with immobilized whole cells of Desulfovibrio vulgaris (Hildenborough) produces an S-shaped voltammogram with both cathodic- and anodic-catalytic-limiting currents in a methyl viologen-containing buffer saturated with H2. Methyl viologen penetrates into the bacterial cells to serve as an electron carrier in the reversible reaction of hydrogenase in the cells and functions as an electron-transfer mediator between the bacterial cells and the electrode, thus producing the catalytic currents for the evolution and consumption of H2. An equation for the catalytic current that takes into account the reversible hydrogenase reaction explains well the shape of the voltammogram. The potential at null current on the voltammogram agrees with the potential determined by potentiometry with the same electrode, which is equal to the redox potential of the H+/H2 couple in the solution--the standard potential of a hydrogen electrode at the pH of the solution. When D. vulgaris cells are suspended in an argon-saturated buffer containing methyl viologen, the suspension produces a catalytic current at a bare glassy carbon electrode for the evolution of H2. Analysis of the current by a theory for a catalytic current for a unidirectional nonlinear enzyme catalysis allows us to determine the kinetic parameters of the reaction between methyl viologen and hydrogenase in intact D. vulgaris cells. Thus we obtain the apparent Michaelis constant for methyl viologen cation radical, K'MV.+ = 0.16 mM, and the apparent catalytic constant (that is, the turnover number per D. vulgaris cell), zkcat,H+ = 1.2 x 10(7) s-1, for the H2 evolution reaction at pH 5.5 and at 25 degrees C, z being the number of hydrogenases contained in a D. vulgaris cell. The bimolecular reaction rate constant, kcat,H+/K'MV.+, of the reaction between methyl viologen cation radical and oxidized hydrogenase in intact D. vulgaris cells is estimated as 4.2 x 10(7) M-1 s-1. Similarly, the bimolecular reaction rate constant, kcat,H2/K'MV2+, of the reaction between methyl viologen and reduced hydrogenase is estimated to be 1.2 x 10(7) M-1 s-1 at pH 9.5 and 25 degrees C. Both rate constants are large enough for the reactions to be diffusion-limited processes.

Bacterial Proteins↗

Physiologic and morphologic properties of motoneurons and spindle afferents innervating the temporal muscle in the cat.

Little is known about physiology and morphology of motoneurons and spindle afferents innervating the temporalis and on synaptic connections made between the two. The present study was aimed at investigating the above issues at the light microscopic level by using the intracellular recording and horseradish peroxidase or biotinamide labeling techniques and by the use of succinylcholine (SCh) for the classification of spindle afferents in the cat. Temporalis motoneurons had dendritic trees that ranged from a spherical form to an egg-shaped form. The shape deformation was more prominent for the dendritic trees made by motoneurons located closer to the nuclear border. No axon collaterals of the motoneurons were detected. On the basis of the values for the dynamic index after SCh infusion, temporalis spindle afferents were classified into two populations: presumptive groups Ia and II. The spindle afferents terminated mainly in the supratrigeminal nucleus (Vsup), region h, and the dorsolateral subdivision (Vmo.dl) of the trigeminal motor nucleus (Vmo). The proportion of group Ia afferent terminals was lower in the Vsup than that of group II afferents. In the Vmo.dl, the proportion of group Ia afferent terminals was nearly even throughout the nucleus, but that of group II afferent terminals increased in the more outlying regions. The proportion of terminal distribution in the central region of Vmo.dl was higher for group Ia than group II. The frequency of contacts (presumptive synapses) made by a single spindle afferent on a motoneuron was higher for group Ia than group II. The present study provided evidence that the central organization of spindle afferent neurons is different between groups Ia and II.

Animals↗

Microsphere embolism-induced elevation of nerve growth factor level and appearance of nerve growth factor immunoreactivity in activated T-lymphocytes in the rat brain.

Changes in nerve growth factor (NGF) level and type of cells producing NGF were investigated in the rat brain after sustained cerebral embolism. The NGF level was determined by a two-site enzyme immunoassay specific for NGF. The cerebral cortex, striatum, and hippocampus of the embolized hemisphere maximally contained 2.4-, 2.4-, and 1.7-times higher NGF levels than the corresponding regions of the nonembolized hemisphere. A significant increase was transiently observed for 1 week in the cerebral cortex and striatum, whereas the increase was longer lasting, at least of 4 weeks' duration, in the hippocampus. To examine the localization of NGF-like immunoreactivity (NGF-LI), we used a newly developed anti-NGF peptide antiserum that specifically recognized a 30-kDa molecule(s) in the hippocampal extracts or in NGF cDNA-transfected cells, suggesting that the antibody predominantly reacted with the putative NGF precursor protein(s). NGF-LI, which was localized in neurons of the normal or non-embolized hemisphere, was reduced, and on the embolized side new signals emerged in small non-neuronal cells having a round shape. These included cells with common leukocyte antigen CD45 and T-lymphocyte antigen CD3, which did not appear in the normal or non-embolized hemisphere. NGF-LI and CD3 were colocalized in a substantial number of the cells, suggesting that some activated T-lymphocytes produce NGF for neuronal regeneration after sustained cerebral embolism.

Animals↗

An Analysis of Higher Order Vibration-Torsion-Rotation Interactions and Spectra for a Molecule with an Internal Rotor.

Motivated by attempts to answer the questions (i) if the same order of magnitude is really appropriate for the torsional angular momentum terms P2gamma and the rotational angular momentum term P2 (or P2a), (ii) how to systematically analyze various higher order interaction effects, especially the torsional effects, and (iii) if a reduced Hamiltonian can be used to fit observed spectroscopic data to an accuracy approaching experimental uncertainties over a significant range of quantum states, a detailed discussion is presented on the order of magnitude of a Hamiltonian term Hmln for molecules with an internal rotation. A new scheme of the ordering by magnitude is proposed to analyze the vibration-torsion-rotation (VTR) interactions, in which the importance of the torsional problem is emphasized. The contact transformation technique is applied to the VTR Hamiltonian, which makes it possible to analyze clearly various higher order VTR interactions and their effects in the VTR spectra of the molecule. The resulting formulas are applicable to analyze observed spectra. A reduced torsion-rotation Hamiltonian for the molecule with C3v(M) symmetry is given in the new ordering scheme. As an application, a total of 568 microwave lines with vt </= 3, J </= 42 and K </= 8 for CH318OH have been fitted to 64 molecular constants by using the reduced Hamiltonian with a root mean square (rms) of 0.262 MHz, where the A and E substates are treated simultaneously. About 35 newly assigned lines are added to our former fitting data (M. Ikeda, Y. B. Duan, S. Tsunekawa, and K. Takagi, ApJS, 117, 249 (1998)). Copyright 1999 Academic Press.

Journal Article↗

Analysis of Rotational Transitions in Excited Vibrational States of Propionitrile (C2H5CN).

We have observed rotational transitions of propionitrile (C2H5CN) in the 8-200 GHz region and assigned 208 transitions with J </= 16 and Ka </= 2 in the first excited state of torsional vibration, 244 transitions with J </= 16 and Ka </= 2 in the first excited state of CCN in-plane bending vibration, and 374 transitions with J </= 16 and Ka </= 4 in the first excited state of CCN out-of-plane bending vibration. We simultaneously analyzed these transitions in the three excited vibrational states, combining with the previously reported transitions in the ground vibrational state, on the basis of a Hamiltonian including CCN-bending vibration-torsion-rotation interactions. A total of 1560 transitions were fitted with 0.95-MHz 1varsigma standard deviation, and molecular constants were determined. Copyright 1999 Academic Press.

Journal Article↗

Frequency Measurement of Pure Rotational Transitions of H217O and H218O from 0.5 to 5 THz.

Frequencies of pure rotational transitions of isotopic species of water, H217O, and H218O were measured in the 1-5 THz region with a high-precision far-infrared spectrometer using a tunable radiation source. Measured frequencies of more than 100 spectral lines for each species provide an excellent frequency standard for the far-infrared region. Molecular parameters based on a Watson-type Hamiltonian have been obtained to reproduce the observed frequencies. Copyright 1999 Academic Press.

Journal Article↗

Far-Infrared Rotational Spectrum of ArD+

Rotational transition frequencies of ArD+ were measured with an accuracy of a few hundred kilohertz in the 0.95-4.7 THz region, using a tunable far-infrared radiation source. Effective rotational parameters B, D, and H were determined for the ground vibrational state. The observed frequencies were combined with the previous data on all isotopic species of protonated argon ion to improve the mass-independent Dunham parameters Ukl, DeltaArkl, and DeltaHkl. Copyright 1999 Academic Press.

Journal Article↗

Pharmacological profile of MS-377, a novel antipsychotic agent with selective affinity for sigma receptors.

RATIONALE: MS-377 ((R)-(+)-1-(4-chlorophenyl)-3-[4-(2-methoxyethyl)piperazin-1-yl]me thyl-2- pyrrolidinone L-tartrate) was discovered as a new chemical entity with affinity for sigma receptors and without affinities for dopamine receptors. OBJECTIVE: In the present study, we examined the antipsychotic profile of MS-377 in several in vitro and in vivo experiments. METHODS: As in vitro assays, radioligand binding assays for sigma 1, sigma 2, D2 and 5-HT2 receptors were performed. As in vivo animal models, the effects of MS-377 on several behavioral models induced by phencyclidine (PCP), (+)-N-allylnormetazocine (NANM), apomorphine (Apo) and 5-hydroxytryptamine (5-HTP) were evaluated. All assay systems were conducted using the clinically active antipsychotic agents as reference standards. RESULTS: MS-377 displaced ligand bound to sigma 1 receptors in vitro. However, no such displacement was observed at sigma 2 or 5-HT2 receptors in vitro, or at D2 receptors either in vitro or in vivo. In behavioral studies, MS-377 inhibited both NANM- and PCP-induced head-weaving at low doses in mice and rats, whereas antipsychotic agents used in the present study were only effective against NANM-induced head-weaving behavior in mice. In addition, MS-377 antagonized Apo-induced climbing behavior and 5-HTP-induced head-twitching behavior in mice. MS-377 was inactive in models of extrapyramidal side effect (EPS) liability such as prevention of Apo-induced stereotypy and induction of catalepsy in rats. CONCLUSION: The present study demonstrated that MS-377 had not only anti-PCP activity but also anti-dopaminergic and anti-serotonergic activities in vivo, without acting directly through D2 or 5-HT2 receptors. Therefore, MS-377 could be a novel antipsychotic agent with clinical efficacy for overall symptoms of schizophrenia including its negative symptoms and without EPS liability.

Amisulpride↗

Deficiency of SHP-1 protein-tyrosine phosphatase activity results in heightened osteoclast function and decreased bone density.

Mice homozygous for the motheaten (Hcphme) or viable motheaten (Hcphme-v) mutations are deficient in functional SHP-1 protein-tyrosine phosphatase and show severe defects in hematopoiesis. Comparison of femurs from mev/mev mice revealed significant decreases in bone mineral density (0.33 +/- 0.03 mg/mm3 for mev/mevversus 0.41 +/- 0.01 mg/mm3 for controls) and mineral content (1.97 +/- 0.36 mg for mev/mevversus 10.64 +/- 0.67 for controls) compared with littermate controls. Viable motheaten mice also showed reduced amounts of trabecular bone and decreased cortical thickness. These bone abnormalities were associated with a 14% increase in numbers of multinucleated osteoclasts and an increase in osteoclast resorption activity. In co-cultures of normal osteoblasts with mutant or control bone marrow cells, numbers of osteoclasts developing from mutant mice were increased compared with littermate control mice. Although mev/mev osteoclasts develop in the absence of colony-stimulating factor (CSF)-1, nevertheless cultured osteoclasts show increased size in the presence of CSF-1. CSF-1-deficient osteopetrosis (op/op) mutant mice develop severe osteosclerosis. However, doubly homozygous mev/mevop/op mice show an expansion of bone marrow cavities and reduced trabecular bone mass compared with op/op mice. Western blot analysis showed that several proteins that were markedly hyperphosphorylated on tyrosine residues were detected in the motheaten osteoclasts, including a novel 126-kd phosphotyrosine protein. The marked hyperphosphorylation of a 126-kd protein in motheaten osteoclasts suggests that this protein depends on SHP-1 for dephosphorylation. These findings demonstrate that the decreased SHP-1 catalytic activity in me/me and mev/mev mice results in an increased population of activated osteoclasts and consequent reduction in bone density.

Animals↗

Effect of intravenous omega-6 and omega-3 fat emulsions on nitrogen retention and protein kinetics in burned rats.

The effect of omega-3 fat emulsion on nitrogen retention and kinetics in relation to fatty acid profile were investigated in burned rats receiving total parenteral nutrition (TPN). A fat emulsion of a structured symmetrical triacylglycerol containing only eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (2:1) was prepared. Sprague-Dawley rats were fed by fat-free chow for 2 wk. Then rats were fed exclusively with one of three types of TPN for 7 d. Animals in group C received fat-free TPN (n = 11). Group omega 6 received safflower oil fat emulsion, which accounted for 20% of total caloric intake (n = 11). Group omega 3 received fat emulsion containing only EPA and DHA (1% of total calories, n = 11), in addition to safflower oil emulsion (19% of total calories). On day 5, each rat was subjected to 20% full-thickness scald burns. Rats were sacrificed under ether anesthesia 48 h after burning. The rats in group C became deficient in omega-6 essential fatty acids. Cumulative nitrogen balance was decreased significantly in group omega 6. The rates of whole-body protein synthesis were increased significantly in both groups omega 6 and omega 3. In omega 6, however, the rates of whole-body protein breakdown were increased significantly. In conclusion, the rates of whole-body protein breakdown increased and nitrogen retention was aggravated significantly in animals administered the safflower oil emulsion. Significant increases of urinary excretion of total catecholamine were also observed. Prostaglandin E2 and thromboxane B2 concentrations were not significantly different among three groups. Supplementation with the new omega-3 fat emulsion, however, improved protein metabolism in burned rats receiving TPN.

Animals↗

Changes in immune function following surgery for esophageal carcinoma.

Changes in immune function due to surgical injury have been well-documented. Immunosuppression is one of the causes of infectious complications leading to organ dysfunction in critical illness. It is not known what kind of surgery in the daily clinical practice causes immunosuppression. Stress response and immune function following surgery for esophageal carcinoma, assuming a highly-stressed operation, were studied and then compared with the stress response and immune function following gastric surgery, a moderately-stressed procedure. Forty patients who underwent esophagectomy and 39 patients receiving gastric operation were studied. The concentrations of serum interleukin-6 (IL-6) were measured preoperatively, at 1, 2, and 6 h, and at 1, 3, and 10 d after operation. Total protein, serum albumin, rapid turnover protein, serum CRP, and cortisol were measured before operation and at 1, 3, 7, and 21 d after operation. ConA- and PHA-stimulated lymphocyte proliferation, IgA, IgG, and IgM were also measured preoperatively, and on 7 and 21 d following surgery. The patients were fed exclusively by total parenteral nutrition (TPN). A striking rise of IL-6 was observed, with a peak in both groups at 1 to 6 h following operation. The peak values were 419+/-30 pg/mL, which was approximately twice as high in the esophagectomy patients as in the gastrectomy patients (195+/-40 pg/mL). CRP and cortisol also increased after operation, and these increases were also significantly greater in the esophagectomy patients. ConA- and PHA-stimulated lymphocyte proliferation decreased significantly 7 d after esophagectomy (P<0.05), but was unchanged in the patients receiving gastrectomy. Suppression of cellular immunity correlated significantly with serum cortisol, and was preceded by a rise in serum IL-6. The IgA, IgG, and IgM levels, however, remained unchanged from their preoperative values throughout the study in both groups. Nutritional status in terms of serum protein, albumin, and rapid turnover protein, decreased postoperatively, but there was no difference between the two groups. It is, therefore, concluded that cell-mediated immunosuppression, preceded by a hyperinflammatory response, is an observable reaction in patients following esophageal surgery, but not in patients undergoing gastric surgery.

Aged↗

Theophylline induces apoptosis of the IL-3 activated eosinophils of patients with bronchial asthma.

In bronchial asthma, eosinophils are upregulated and their survival is suggested to be prolonged by the action of some cytokines such as Interleukin (IL)-3, IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF). We find here that the survival of eosinophils in the peripheral blood of patients with asthma is correlated with the serum levels of IL-3 but not of IL-5 and GM-CSF. Interestingly, theophylline is revealed to induce apoptosis of the prolonged survival eosinophils by IL-3, as judged by morphological changes and nucleosomal DNA fragmentation. During the apoptosis, caspase-3 in eosinophils stimulated by IL-3 is activated by theophylline. The substrate of caspase-3, poly (ADP-ribose) polymerase (PARP), is cleaved in the eosinophils after theophylline treatment. These results suggest that theophylline is able to induce apoptosis of the IL-3 activated eosinophils in patients with bronchial asthma, and that its clinical effectiveness may be due to the reduction of inflammatory cells in the airway.

Journal Article↗