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Biomedical subjects

M Furukawa

Publications and source records attributed to M Furukawa.

At least 181 records · Page 10Linked to original sources
PubMed1996

The Na-K-Cl cotransporters in the rat cochlea: RT-PCR and partial sequence analysis.

Nonsensory epithelial cells of the mammalian cochlea contribute to the production of the endolymph. The presence as well as the function of the Na-K-Cl cotransporter has been suggested, but not yet been proved. To identify the Na-K-Cl cotransporter isoforms expressed in the cochlea, mRNA was extracted from the cochlear lateral wall. After reverse transcription, resulting cDNA was amplified by polymerase chain reaction (PCR) with primers specific for Na-K-Cl cotransporter isoforms. In the rat cochlear lateral wall, mRNA homologous to the mouse bumetanide-sensitive Na-K-Cl cotransporter (mBSC2) was detected. These results suggest that the basolateral localization of the cotransporter in the marginal cell is involved in the secretory process of the endolymph.

Animals↗
PubMed1996

Subcellular distribution of protein kinase C in the living outer hair cell of the guinea pig cochlea.

Immunohistochemical staining using isoform-specific antibodies and intracellular localization using fluorescent probes for protein kinase C (PKC) were evaluated in the cochlear outer hair cell (OHC). Among three isoforms of classic PKC, PKC alpha was selectively stained in the fixed OHC as well as inner hair cells under a surface preparation method. Two types of fluorescent probes to detect subcellular localization of PKC were observed with a confocal laser scanning microscopy in the present study, fim-1 diacetate which binds to the ATP-competitive catalytic domain of PKC and Bodipy FL C12-phorbol acetate which binds to specific site localized to the first cysteine-rich loop of the C1 region in the regulatory domain. High fluorescence intensity of both dyes was observed in subcuticular and subsynaptic regions, infracuticular network, and along the lateral wall. The displacement experiments to evaluate binding specificity were performed by incubating Bodipy FL C12-phorbol acetate in the presence of 10 microM phorbol 12-myritate 13-acetate (PMA) and the fluorescence was totally disappeared. For the acute treatment of phorbol ester, cells were preincubated with 1 microM PMA 30 min before loading with fim-1 diacetate. The brightest area in the plasma membrane became much larger as compared with untreated cells, which suggests a dramatic translocation of PKC to the plasma membrane. The biological functions involving PKC in the OHC are discussed.

Adenosine Triphosphate↗
PubMed1996

Butylated hydroxyanisole blocks the inhibitory effects of tumor necrosis factor-alpha on collagen production in human dermal fibroblasts.

Tumor necrosis factor-alpha (TNF-alpha) has been demonstrated to selectively decrease the production of type I and type III collagens in human dermal fibroblasts. The effects of the commonly used food antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol, propyl gallate, superoxide dismutase (SOD), and catalase on TNF-alpha-induced growth enhancement and collagen metabolism were evaluated in the present study. BHA at concentrations of both 5 x 10(-5) and 10(-4) M inhibited cell proliferation and DNA synthesis induced by 10 ng/ml TNF-alpha in human dermal fibroblasts, while other antioxidants had minimal effects. Further, BHA (5 x 10(-5) M and 10(-4) M) significantly blocked TNF-alpha-induced decreases in collagen synthesis. These results suggest that antioxidants such as BHA may be involved in the modulation of collagen synthesis by TNF-alpha in human dermal fibroblasts.

Antioxidants↗
PubMed1996

Long-term progress in reading abilities in hearing-impaired children trained by the Kanazawa method.

The speech and language training for deaf children at our clinic is done by the Kanazawa method, consisting of reception and production training in sign language (SL) along with auditory/oral language (OL), and written language (WL) training. The present investigation was undertaken to explore long-term progress in reading comprehension abilities in 14 hearing-impaired children who were trained by the Kanazawa method before entering elementary schools. Progress in reading comprehension was evaluated using a standard reading test for hearing peers. The results obtained were as follows: (i) The average score in reading ability just before entering elementary schools was a second level, (ii) this high score was maintained almost longitudinally, and (iii) on the other hand, the hearing-impaired children who had poor reading scores on entering schools continued to score poorly in higher grades. These results suggest that early presentation of WL is effective in the acquisition of reading ability, which is especially difficult for the hearing-impaired.

Adolescent↗
PubMed1996

Olfactory evoked potentials produced by electrical stimulation of the olfactory mucosa.

We stimulated the olfactory mucosa electrically and elicited evoked potentials in rabbits. A bipolar stimulating electrode was placed on the olfactory region of the nasal mucosa via an anterior naris non-invasively. Evoked potentials were detected from the surface of a head. In most instances they were composed of triphasic negative-positive-negative peaks, the latencies of these peaks were about 25, 40, and 65 ms, respectively. This peak complex seemed to originate in the olfactory bulb. This method is non-invasive and is applicable to studying the olfactory system in animals and also in humans.

Animals↗
PubMed1996

A chronic organized masseter abscess causing trismus resolved by hemi-masseter myotomy.

We present a 62-year-old patient with a chronic organized abscess of the right masseter muscle that developed following parotidectomy. This patient's chronic abscess originated from an infection in the masticator space from the second molar. Cases of repeated parotitis should lead one to suspect a masticator space infection. In this case, the cicatricical masseter muscle produced severe trismus. Total eradication of the abscess and myotomy of the masseter resolved the problem completely. We should pay attention to the dental condition in case of masticator space infection, especially in case of masseter muscle infection mimicking parotitis.

Abscess↗
PubMed1996

Effects of nimesulide, a preferential cyclooxygenase-2 inhibitor, on carrageenan-induced pleurisy and stress-induced gastric lesions in rats.

Intrapleural injection of carrageenan in rats increased prostaglandin E2 (PGE2) production and induced newly synthesized cyclooxygenase-2 (COX-2) in pleural exudate cells without affecting COX-1 levels. Nimesulide, a preferential inhibitor of COX-2, reduced pleural PGE2 production and was almost as active as indomethacin and 10 times more active than ibuprofen. Only COX-1, and nc COX-2, was detected in gastric mucosal cells, and PGE2 concentration of gastric mucosa was significantly decreased by indomethacin and ibuprofen. The decrease in gastric PGE2 production induced by indomethacin and ibuprofen was enhanced in stressed rats, resulting in aggravation of stress-induced gastric lesions at anti-inflammatory doses. However, nimesulide did not produce stress-induced gastric lesions even at 30 times the anti-inflammatory dose. This supports the hypothesis that inhibition of COX-1 causes unwanted side effects and inhibition of COX-2 produces anti-inflammatory effects.

Animals↗
PubMed1996

Effects of non-steroidal anti-inflammatory drugs on prostaglandin E2 production by cyclooxygenase-2 from endogenous and exogenous arachidonic acid in rat peritoneal macrophages stimulated with lipopolysaccharide.

Lipopolysaccharide (LPS) stimulated prostaglandin E2 (PGE2) formation and induction of cyclooxygenase-2 (COX-2) expression without changing the levels of COX-1 protein in rat peritoneal macrophages. Non-steroidal anti-inflammatory drugs (NSAIDs) (nimesulide, indomethacin and ibuprofen) strongly inhibited LPS-stimulated PGE2 production without any effect on COX-2 protein expression, suggesting that NSAIDs are active in inhibiting the ability of COX-2 to convert arachidonic acid (AA) endogenously released in response to LPS stimulation. Exogenous AA can be converted to PGE2 by both COX isoforms even in LPS-stimulated macrophages. NSAIDs inhibited PGE2 production from exogenous AA mediated by both COX-1 and COX-2. However, the two isoforms interacted differentially with different NSAIDs. Furthermore, NSAIDs were distinctly more active in inhibiting PGE2 production from endogenous AA than that from exogenous AA. These data suggest that PGE2 production through COX-2 from exogenous AA may not be subject to the same regulatory processes as that from endogenous AA and the two metabolic processes may be differentially sensitive to different NSAIDs.

Animals↗
PubMed1996

Relapsing polychondritis presented as inner ear involvement.

We report a rare case of relapsing polychondritis with an initial symptom of inner ear involvement. This 53-year-old Japanese man experienced a hearing difficulty, tinnitus in both ears, and dizziness of sudden onset, but lacked auricular chondritis at that time, which is the most frequent finding in relapsing polychondritis. Thus it was difficult to reach a correct diagnosis. Steroid therapy, with oral prednisolone 15 mg daily, was effective. Almost two months after we began the steroid therapy, the patient complained of losing interest in his work and reported a hallucination vision on the TV screen, so the dose of prednisolone was decreased to 10 mg. The hallucinations then disappeared, but the serum level of C-reactive protein increased highly. To reduce the dose of prednisolone, we tried low-dose oral methotrexate. However, we had to discontinue it when the patient experienced severe vomiting and diarrhoea. As adjuvant therapy, we then administered Sho-saiko-to, Chinese herbal medicines with few side effects. Symptoms and laboratory abnormalities then improved markedly.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

T-cell receptor repertoire of infiltrating T cells in lachrymal glands, salivary glands and kidneys from alymphoplasia (aly) mutant mice: a new model for Sjögren's syndrome.

Alymphoplasia (aly) mice are thought to provide a new model for systemic Sjögren's syndrome (SS), since they reveal remarkable infiltration of mononuclear cells into salivary glands, lachrymal glands and kidneys, and show histological findings similar to those in patients with SS. Cell transfer experiments demonstrate that T cells induce the infiltration of mononuclear cells into several tissues in aly mice. To analyse the pathogenesis of cell infiltration in various tissues, we examined T-cell receptor (TCR) V beta usage of T cells in salivary glands, lachrymal glands and kidneys from aly mice, using family-polymerase chain reaction (PCR) and PCR-single-strand conformation polymorphism (SSCP) methods. The results of SSCP demonstrated that the infiltrating T cells in the three organs expanded clonally, suggesting that they proliferate by antigen-driven stimulation. Some TCR V beta genes (V beta 1, 3, 6, 11, 12, 16) were commonly used in salivary glands, lachrymal glands and kidneys, while the V beta 7 gene was specifically expressed in kidneys. SSCP also showed that there were a few shared T-cell clones (V beta 3- and V beta 6-positive cells) among the three tissues. Indeed, sequence analysis of accumulated T cells showed that a conserved amino acid (leucine) at position 98 in the TCR V beta complementary determining region (CDR) 3 was detected in all organs at high frequency (41-57%) and the amino acid sequence motif (LG) was specifically conserved at a frequency of 32% in the three organs. In conclusion, T cells that infiltrate into lachrymal glands, salivary glands and kidneys of aly mutant mice might recognize shared common epitopes in all three organs and a kidney-specific antigen.

Animals↗
PubMed1996

Effect of estrogens on plasma platelet-activating factor acetylhydrolase and the timing of parturition in the rat.

In the present study we examined the effects of estrogens on plasma platelet-activating factor acetylhydrolase (PAF-AH) activity in pregnant rats in an attempt to further define the role of platelet-activating factor (PAF) in parturition. The plasma PAF-AH activity decreased starting on Day 13 of pregnancy and reached its lowest level by Day 19 (36.5 +/- 5.7 nmol.min-1.ml-1 plasma, mean +/- SD). The maternal plasma PAF-AH activity rapidly increased to 67.3 +/- 3.5 nmol.min-1.ml-1 plasma by Day 2 postpartum, to 88.8 +/- 14.4 by Day 7, and to 109.1 +/- 4.4 by Day 21, returning to nonpregnant levels by Day 35 in the dams that were allowed to nurse through Day 21. The PAF-AH activity did not increase in dams from which the pups were removed 2 days after delivery. When 17 alpha-ethynylestradiol (0.25 mg/kg) was administered s.c. to pregnant rats for 3 days starting at Day 17 of pregnancy, the plasma PAF-AH activity in the animals decreased by 80% on Day 19, and the rats delivered prematurely on Day 21. When a similar dose of 17 alpha-ethynylestradiol was injected into the pregnant rats for 3 days starting on Day 15, the enzyme activity again decreased by approximately 80% on Day 17 and Day 19 of pregnancy; however, it returned to a value similar to that seen in the controls by Day 21, and the time at which the treated rats delivered was similar to that for the control animals. These observations provide further support for a role of PAF and PAF-AH and their possible regulation by estrogens in the initiation and maintenance of parturition.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1996

Prognostic value of EGFR and TGF-alpha in early laryngeal cancer treated with radiotherapy.

The purpose of this study was to determine the overexpression of both epidermal growth factor receptor (EGFR) and transforming growth factor-alpha (TGF-alpha) (a ligand of EGFR) in early laryngeal squamous cell carcinoma. In addition, we attempted to evaluate the prognostic values of our findings. Expression of EGFR and TGF-alpha in tumor tissue was examined immunohistochemically in 68 patients who had been treated with radiotherapy for early laryngeal cancer. Overexpression of the two factors was noted in 42.6% and 55.9%, respectively. No significant differences due to age, tumor size, and location or grade of cancer tissues were seen. Higher survival rates, found in patients with EGFR (-) and TGF-alpha (-) tumors as compared with those with EGFR (+) and TGF-alpha (+) (97.4%, 100% and 86.2%, 86.8%, respectively), were not statistically significant. The recurrence rates were similar between EGFR (+) and EGFR (-) (37.9% and 35.9%, respectively). However, the recurrence rate in patients with TGF-alpha (+) was significantly higher (57.9%) than in those with TGF-alpha (-) (10%; P<.01). Therefore overexpression of TGF-alpha may be an important indicator for recurrence in patients with early laryngeal squamous cell carcinoma treated by irradiation.

Adult↗
PubMed1996

Differentiation between schwannoma of the vagus nerve and schwannoma of the cervical sympathetic chain by imaging diagnosis.

Ultrasonography, computed tomography, and magnetic resonance imaging were performed to differentiate preoperatively between schwannomas of the vagus nerve and schwannomas of the cervical sympathetic chain by observing the position of schwannomas in regard to the surrounding blood vessels. Ultrasonography also permitted direct visualization of the vagus nerve, so its position relative to the schwannoma could be examined. In schwannomas of the vagus nerve the schwannoma grew between the common carotid artery and the internal jugular vein or between the internal carotid artery and the internal jugular vein, resulting in an increase in the distance between the artery and vein (separation). In schwannomas of the cervical sympathetic chain, no separation was observed between the internal jugular vein and the common carotid artery or internal carotid artery. Ultrasonography with a 7.5-MHz transducer showed the derivation of the tumor from the vagus nerve in schwannomas of the vagus nerve but showed the vagus nerve on the tumor surface in schwannomas of the cervical sympathetic chain.

Adolescent↗
PubMed1996

Measurement of pancreatic blood flow with the intraductal electrode method of the hydrogen clearance technique in acute pancreatitis in rats.

Measurement of local pancreatic blood flow during acute pancreatitis is thought of as being technically difficult in smaller animals. In this study, we first employed an intraductal electrode method of the hydrogen clearance technique for measurement of changes in local pancreatic blood flow in two types of acute pancreatitis in rats, then compared this method with an interstitial electrode method that has been used in rats. There was a very close correlation between these methods (r = 0.998, p < 0.001). The intraductal electrode method was easily performed and caused minimal tissue damage.

Acute Disease↗
PubMed1996

A prospective randomized trial of the preventive effect of pre-operative transcatheter arterial embolization against recurrence of hepatocellular carcinoma.

To clarify whether pre-operative transcatheter arterial embolization (TAE) improves survival after hepatectomy, a prospective randomized comparative study was done. Of a total of 115 registered patients having solitary hepatocellular carcinoma (HCC) 2 to 5 cm in diameter, 18 (15.7%) were excluded after randomization. As a result, 97 patients were chosen as subjects and divided into two groups: hepatectomy with (group A: n=50) and without (group B: n=47) pre-operative TAE. The period of observation of the patients who survived the surgery was between 4.0 and 6.6 years. The randomization appeared to have provided well-balanced groups of patients and the clinico-pathological characteristics of the two groups were quite similar. The necrotic part of the cancerous lesions, as confirmed by operative specimens, amounted to 74.8+/-33.4% (mean +/-SD) in group A and 6.8+/-7.2% in group B (P<0.01). However, the cancer-free survival rates after hepatectomy in both groups showed little difference (39.1+/-7.0 (%+/-SE) and 31.1+/-0.1, respectively). We speculate that TAE is not effective against such HCC accessory lesions as minute intrahepatic metastasis and tumor thrombus and that pre-operative TAE does not improve post-operative survival.

Adult↗
PubMed1996

Acute pancreatitis induced by hypercalcaemia associated with adult T-cell leukaemia: a case report.

A 44 year old Japanese woman with adult T-cell leukaemia (ATL) was admitted to Kyushu University hospital to receive a course of alpha-interferon treatment. She experienced a sudden onset of hypercalcaemia and epigastric pain associated with an increase in the level of pancreatic enzymes. Her serum parathyroid hormone related protein level was above normal although her high sensitive PTH level was within the normal range. Ultrasonography and computed tomography (CT) of the abdomen showed enlargement of the pancreas with indistinct margins and massive accumulation of extrapancreatic fluid. Cullen's sign was observed. A few days after the onset of acute pancreatitis, the serum amylase level increased to 3400 IU/L, and the serum calcium level fell to 4.2 mg/dL from 13.3 mg/dl. Her fasting blood glucose level increased to 242 mg/dL. Although the first episode of pancreatitis appeared to respond to treatment, she experienced a second episode of pancreatitis accompanied by an elevation of the serum calcium level. These findings suggest that acute pancreatitis was caused by hypercalcaemia associated with ATL.

Acute Disease↗