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Biomedical subjects

Y Iwabuchi

Publications and source records attributed to Y Iwabuchi.

At least 37 records · Page 2Linked to original sources
PubMed1995

Effects of vasoactive intestinal peptide and its homologues on the acetylcholine-mediated secretion of fluid and protein from the rat submandibular gland.

1. Acetylcholine-mediated (ACh-mediated) secretion of fluid and protein from rat submandibular glands was enhanced by intravenous injection of vasoactive intestinal peptide (VIP) and of secretin but not of peptide histidine isoleucine (PHI) or gastric inhibitory peptide (GIP). 2. When VIP and ACh were administered together, the enhancement of fluid secretion was inhibited by pretreatment with atropine or 4-DAMP and the enhancement of protein secretion was inhibited by pretreatment with atropine or phentolamine. 3. The enhancement of the ACh-induced secretion of fluid by secretin was strongly inhibited by pretreatment with atropine, and it was weakly inhibited by pretreatment with phentolamine or haloperidol. 4. These results suggest that the synergistic effects of VIP, PHI, secretin and GIP on the ACh-mediated secretion of fluid and protein from the rat submandibular gland do not reflect the extent of the structural homology of each peptide to VIP.

Acetylcholine↗
PubMed1995

Combined dorsal forearm and lateral arm flap.

The free latissimus dorsi musculocutaneous flap and the free groin flap have been used for the coverage of medium- to large-sized soft-tissue defects in the hand. However, these are often too bulky for the hand, requiring secondary operation for thinning. We have used the dorsal forearm flap combined with the lateral arm flap for the coverage of large soft-tissue defects in the hand. This flap is based on the reversed vascular pedicle of the posterior interosseous artery. The posterior radial collateral branch of the profunda brachii artery is then anastomosed to the recipient vessel to augment the vascular supply to the lateral arm flap. We have used this combination flap in two clinical cases and achieved one-stage soft-tissue reconstruction of the hand.

Adult↗
PubMed1995

[Catalytic antibody and its medical applications].

Catalytic antibodies will not only provide new insight into the general potential of natural enzymes, but may also afford novel catalysts to facilitate reactions not catalyzed by natural enzymes. One goal of studying catalytic antibodies is to generate tailor-made catalysts for applications in medicine. An example of a possible use with catalytic antibodies is related to the action of prodrugs. In the rational design of prodrugs, it is necessary to consider (a) what structural modifications of the parent molecule are necessary to reduce or eliminate the particular undesirable effects, and (b) what enzymes are available in vivo to regenerate the parent molecule from the prodrug. However, the design of structurally related analogues of a parent molecule is limited by the enzyme's specificity, the type of reaction catalyzed, and the enzyme distribution and level. Using catalytic antibody technology for the novel design of prodrugs allows for effective structural modifications of the molecule in question. It is also a valuable aid in overcoming the problem of drug delivery by using bi-functional chimeric antibody technology, through which site-specific antibodies are combined with antibodies catalyzing reactions that cannot be accomplished by natural enzymes in vivo. In this review, we describe the first example of prodrug activation via catalytic antibodies as well as future aspects of catalytic antibodies of medical interest.

Anti-Bacterial Agents↗
PubMed1994

Sialogogic activities of SNI-2011 compared with those of pilocarpine and McN-A-343 in rat salivary glands: identification of a potential therapeutic agent for treatment of Sjörgen's syndrome.

1. We examined the sialogogic activities in rat major salivary glands of SNI-2011, in comparison with those of pilocarpine and McN-A-343, and we characterized the subtypes of muscarine receptors that are involved in the sialogogic responses to SNI-2011 and McN-A-343. 2. SNI-2011 at doses ranging from 1 to 10 mg/kg (i.v.) increased the secretion of saliva in a dose-dependent manner. The dose-response curves for SNI-2011 were approximately parallel to curves for pilocarpine but the potency of SNI-2011 was about 25-fold lower than that of pilocarpine. 3. The total volume of saliva secreted in response to McN-A-343 was very much less than that secreted in response to SNI-2011. 4. The salivation induced by SNI-2011 and by McN-A-343 was inhibited by various antagonists with the following rank order of potency: 4-DAMP >> pirenzepine >> AF-DX 116. 5. Our results suggest that the sialogogic effects of SNI-2011 and McN-A-343 are mediated by direct stimulation of M3 receptors in salivary glands and that SNI-2011 may prove useful in the management of xerostomia in patients with Sjögren's syndrome.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
PubMed1994

Effects of vasoactive intestinal peptide and its homologues on the noradrenaline-mediated secretion of fluid and protein from the rat submandibular gland.

1. Noradrenaline-mediated secretion of fluid and protein from rat submandibular glands was enhanced by vasoactive intestinal peptide (VIP) and secretin but not by peptide histidine isoleucine (PHI) or gastric inhibitory peptide (GIP). 2. The synergistic effect of the combination of VIP with noradrenaline (NA) was antagonized by pretreatment with prazosin or phentolamine but not by pretreatment with yohimbine or propranolol. 3. These results suggest that VIP and secretin but not PHI and GIP can significantly enhance the secretion of fluid and protein that is mediated by NA in rat submandibular gland and that the synergistic effect of VIP and NA involves both alpha 1-adrenergic receptors and receptors for VIP.

Adrenergic Antagonists↗
PubMed1994

Effects of vasoactive intestinal peptide and its homologues on the substance P-mediated secretion of fluid and protein from the rat submandibular gland.

1. Vasoactive intestinal peptide (VIP) and secretin elicited slight secretion of saliva but peptide histidine isoleucine (PHI) and gastric inhibitory peptide (GIP) failed to elicit secretion of saliva from rat submandibular glands. 2. Substance P (SP)-mediated secretion of fluid and protein were enhanced by VIP and secretin but not by PHI or GIP. 3. These results suggest that the effects of VIP, PHI, secretin and GIP on the secretion of fluid from rat submandibular glands and the synergistic effects of VIP and its homologues on the SP-mediated secretion of fluid and protein do not correspond to the extent of the structural homology of each analogue to VIP.

Amino Acid Sequence↗
PubMed1994

Effects of cholinergic and adrenergic agonists on the secretion of fluid and protein by submandibular glands of the guinea-pig and the mouse.

Significant differences were observed between the guinea-pig and the mouse in terms of the secretion of fluid, protein and secretory granules from submandibular glands in response to pilocarpine, phenylephrine and isoproterenol. In both the guinea-pig and the mouse, the secretory responses induced by pilocarpine, phenylephrine and isoproterenol were inhibited by pretreatment with 4-DAMP, phentolamine and propranolol, respectively. The results suggest that the submandibular glands of the guinea-pig and the mouse have M3-cholinoreceptors, as well as alpha- and beta-adrenoceptors, and that these receptors play different roles in the secretion of fluid, protein and secretory granules from guinea-pig and mouse submandibular glands.

Adrenergic Agonists↗
PubMed1994

[Clinical evaluation of asymptomatic sinus disease detected by MRI].

The detection of lesions of the paranasal sinuses as incidental findings during magnetic resonance imaging of patients suspected of intracranial disease who have no nasal symptoms has been far more common than we expected. The present study was performed on 325 patients a mean age of 60.7 years. Medical histories were taken whether they had any nasal symptoms or not. Asymptomatic sinus disease was present in 41.6% of the 257 patients who had no nasal symptoms, and 9.7% of the patients had either marked mucosal thickening, excessive fluid or polyps in the maxillary sinuses. Although the mean age of these patients was comparatively high, we can infer that 1 in 10 have relatively severe sinus lesions. Mucociliary transport time was measured using the saccharin method in 15 patients who had sinus disease but no nasal symptoms. The mean transport time was 15.6 minutes and within normal limits. Routine ENT examination revealed no lesions in the nasal cavity of any of the subjects. We classified the patients with asymptomatic sinus disease into two groups; group A: patients with sinus disease associated with some nasal manifestations but who do not complain about them, group B: patients who have sinus disease but do not have any nasal problems. Group B represents genuine asymptomatic sinus disease in the narrow sense. Most asymptomatic patients in this study appeared to belong to group B. They had some sinus disease, but because their mucociliary function in their nasal cavity was normal, they did not have any nasal symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

X-Neu5Ac: a novel substrate for chromogenic assay of neuraminidase activity in bacterial expression systems.

A chromogenic substrate 1, 5-bromo-4-chloroindol-3-yl 5-acetamido-3,5-dideoxy-alpha-D-glycero-D-galacto-2-nonulopyranosidon ic acid (X-Neu5Ac), has been synthesized to facilitate the screening of bacterial colonies or plaques for the detection of either natural or mutant neuraminidase activity. Substrate 1 was hydrolyzed by neuraminidase isolated from Clostridium perfringens to release a halogenated indol-3-ol 2 that undergoes rapid aerobic oxidation to form the dark blue pigment, 5,5'-dibromo-4,-4'-dichloroindigo 3. Preliminary kinetic studies indicate that this compound is a good substrate (Km 0.89 x 10(-3) M) for neuraminidase and is quite stable under identical conditions in the absence of enzyme. These results suggest that X-Neu5Ac 1 can be useful to screen for bacterially-encoded enzyme production directly on agar plates.

Chromogenic Compounds↗
PubMed1992

Sialogogic effects on rat submandibular gland of analogs of the C-terminal hexapeptide of substance P.

The sialogogic response of submandibular glands to analogs of the C-terminal hexapeptide of substance P with various amino acids at the N-terminus was investigated in urethane-anesthetized rats. The rank order of potencies was as follows: SP greater than (pGlu6)SP6-11 much greater than (Dab6)SP6-11 greater than (Orn6)SP6-11 greater than (Gln6)SP6-11 greater than (Lys6)SP6-11 much greater than (Ala6)SP6-11. These results suggest that the sialogogic activity of the analogs of the C-terminal hexapeptide is influenced by the steric effects of the N-terminal amino acid, and the nature of its side chain is of particular importance.

Animals↗
PubMed1992

Effects of cholinergic and adrenergic agonists on the secretion of fluid and protein by submandibular glands of the hamster and the rat.

1. Significant differences were observed between the hamster and the rat in terms of the secretion of fluid and protein from submandibular glands in response to pilocarpine, phenylephrine and isoproterenol. 2. In both the rat and the hamster the secretory responses induced by pilocarpine, phenylephrine and isoproterenol were inhibited by pretreatment with 4-DAMP, prazosin and metoprolol, respectively. 3. These results suggest that the submandibular glands of the hamster and the rat have M3-cholinoreceptors, as well as alpha 1- and beta 1-adrenoceptors, and that these receptors play different roles in the secretion of fluid and protein from hamster and rat submandibular glands.

Animals↗
PubMed1990

[Sensorineural hearing loss following the decompression of the facial nerve].

This study aims to ascertain whether sensorineural hearing loss occurs after the decompression of the facial nerve. Nine patients have undergone decompression of the facial nerve (limited to the vertical segment) by the transmastoid approach were selected as the subjects of this study because the influence of disinfectants and surgical trauma on the inner ear seems to be less severe in this operation than in tympanoplasty. Additionally, this approach seems to be more suitable for judgement of the effect of the drilling noise induced acoustic trauma on the inner ear than tympanoplasty. Though high tone abrupt sensorineural hearing loss was occurred in the operated ear in seven patients, no changes in hearing level were found in the contralateral side ear. Bekesy audiometry performed in only one case revealed Jerger II which suggested some disorder in the cochlea. Not only acoustic trauma induced by the drilling noise but also labyrinthitis occurred via the opened facial canal and the internal ear canal seemed to be the cause of sensorineural hearing loss following the decompression of the facial nerve.

Adult↗
PubMed1989

Effects of metaraminol on the secretion of fluid and glycoproteins from the rat submandibular gland.

The actions of metaraminol on the secretion of fluid and glycoproteins from rat submandibular glands were investigated using phentolamine, propranolol and reserpine. Metaraminol at doses from 1 to 8 mg/kg (i.p.) increased the salivation and the amounts of protein in submandibular saliva in a dose-dependent manner. The salivation induced by metaraminol at 2 mg/kg was inhibited strongly by pretreatment with propranolol, whereas the salivation induced by metaraminol at 8 mg/kg was inhibited strongly by phentolamine. Reserpine inhibited the secretion of fluid caused by both doses of metaraminol. The electrophoretic profiles of saliva evoked by metaraminol at 2 mg/kg revealed two main bands of glycoprotein, I and IV, which originated from the acinus, and the intensities of these bands were decreased by treatment with propranolol, whereas the major band in saliva induced by 8 mg/kg of metaraminol was glycoprotein III, which originated from the granular tubules. The intensity of band III was decreased by pretreatment with phentolamine. These results suggest that metaraminol, at small doses, stimulates mainly the beta-adrenoceptor in the acinus, whereas at large doses, it prominently stimulates the alpha-adrenoceptors in the granular tubules, although metaraminol at small and large doses is able to stimulate alpha- and beta-adrenoceptors in rat submandibular gland.

Animals↗
PubMed1989

Effects of tachykinins on the secretion of fluid and glycoproteins from the submandibular glands of rat, mouse, hamster and guinea pig.

The effects of substance P, neurokinin A, physalamine, and eledoisin on the secretion of fluid and glycoproteins from the submandibular glands of various rodents were investigated. Following i.v. injection of each peptide at a dose of 20 micrograms/kg, the major glycoprotein species secreted from rats and guinea pigs were shown to be electrophoretically identical with those found in the acini. However, saliva was not elicited from the mice and hamsters. These results suggest that in both rats and guinea pigs, tachykinins act on the acinar cells of the submandibular gland only.

Animals↗
PubMed1989

Effects of autonomic agents on the secretion of glycoproteins from the secretory cells of the major salivary glands in rats.

The characteristics of the glycoproteins contained in the secretory segments of the three major salivary glands of adult male rats and the secretion of these various glycoproteins in response to autonomic agents were examined by micro-disc electrophoresis. Characterization of the glycoproteins showed that the acinar segments from the three major salivary glands and the segments of the convoluted granular tubules from the submandibular gland each contain characteristic species of glycoproteins. The glycoproteins characteristic of the acinus of the submandibular gland were secreted into saliva in response to carbachol or dobutamine, those characteristic of the parotid gland by carbachol, methoxamine, or dobutamine, and those of the sublingual gland by carbachol, whereas glycoproteins characteristic of the convoluted granular tubules of the submandibular gland were only elicited by methoxamine. The secretory response of carbachol, methoxamine and dobutamine, respectively, were almost completely reduced by pretreatment with atropine, prazosin and metoprolol. The relative proportions of glycoproteins secreted into the oral cavity from secretory cells of the three major glands varied significantly with the nature of the stimulant.

Animals↗
PubMed1989

[Experimental study on the air streams in the paranasal sinus].

Air streams in the paranasal sinus were investigated using Nose-Sinus Model to contribute to the fundamental knowledge of aerosol therapy. The results obtained were as follows; 1. The velocity of air streams in the paranasal sinus was measured by Laser Doppler Anemometer and the visualization of streams was done by Laser Light Sheet method. 2. The amount of aerosol passed into the maxillary sinus is approximately in proportion to the sectional area of the ostium. 3. A considerable amount of aerosol passing into the sinus was noted under LLS technique applying positive pressure from the choana. From the above results, it is necessary for the effective entrance of aerosol into the sinus first to open the middle meatus wide and to add the intermittent pressure.

Aerosols↗
PubMed1988

Effects of dobutamine and terbutaline on the secretion of glycoproteins from the acinar cells of the rat submandibular gland.

The actions of dobutamine (DOB) and terbutaline (TER) on the secretion of marker glycoprotein (GP) from the secretory cells of the glands and secretion of fluid from rat submandibular gland (SMG) were investigated in combination with two antagonists, metoprolol (MET) and ICI-118551 (ICI). The ED50 value of fluid secretion was 8.7 mg/kg for DOB and 5.9 mg/kg for TER. MET, administered prior to either agonists at a dose of 40 mg/kg, inhibited the fluid secretion. However, the blocking effects of ICI were considerably lower than those of MET. The electrophoretic profiles of GP in DOB-evoked saliva were similar to those in TER-evoked saliva, and included two characteristic main bands of GP I (130 KDa) and GP IV (21.5 KDa) from the acinar cells and a minor band of GP III (31 KDa) which originated in the cells of the granular tubules. When MET was administered at a dose of 5 mg/kg prior to DOB, the intensity of band I decreased, whereas that of band III did not change. These results showed that the SMG of rats contains both beta 1- and beta 2-adrenoceptors and that beta-receptors which mediate the secretion of GP from the acinus and fluid from the gland are mainly of the beta 1-subtype.

Adrenergic beta-Antagonists↗