Biomedical subjects

K Asakura

Publications and source records attributed to K Asakura.

At least 73 records · Page 4Linked to original sources

PubMed1998

Mass screening for lung cancer with mobile spiral computed tomography scanner.

BACKGROUND: The incidence of and mortality from lung cancer have increased steadily. Most lung cancers are not localised when first detected, but early detection is mandatory to improve prognosis. Since curable early cases are hard to visualise with conventional chest radiography, a new diagnostic means must be found. We assessed whether population-based mass screening with a spiral computed tomography scanner could contribute substantially to detection of smaller cancers, and decrease mortality. METHODS: In 1996, we screened in a mobile unit 5483 individuals from the general population of Matsumoto, Japan, aged between 40 years and 74 years who had undergone annual chest radiography (miniature fluorophotography) and cytological assessment of sputum. All participants had a low-dose X-ray spiral computed tomography (CT) scan of the thorax; 3967 also underwent miniature fluorophotography. We compared smokers and non-smokers. Further assessments were done for probably benign but suspicious lesions; suspicion of cancer; and indeterminate small nodules by chest radiography and conventional CT, with additional transbronchial biopsy when possible. Thoracotomy was recommended when it was strongly suspected that the patients had lung cancer. FINDINGS: 19 patients were diagnosed as having lung cancer--14 with suspicion of lung cancer, three with benign but suspicious lesions, and two with indeterminate small nodules. 18 cases were surgically confirmed, and one was clinically diagnosed. The mean size of lesions was 17 mm (range 6-47). In four of 19 patients, lung abnormality was seen on CT and miniature fluorophotography. The lung-cancer detection rate with CT was 0.48%, significantly higher than the 0.03-0.05% for standard mass assessments done previously in the same area. CT missed one case that was found solely on a sputum cytology examination. INTERPRETATION: Our results show that miniature fluorophotography or conventional chest radiography, which have been the main diagnostic techniques for lung cancer, showed few small cancers. CT was more accurate in mass screening for lung cancer and led to early detection and an accurate diagnosis of lung cancer, and should be considered in future health plans.

Adult↗

PubMed1998

Radiotherapy for Kimura's disease: the optimum dosage.

PURPOSE: To evaluate retrospectively the optimum dosage of irradiation for Kimura's disease. METHODS AND MATERIALS: Twenty patients with Kimura's disease were treated with radiotherapy. The sex ratio was 19 males to 1 female. The mean ages at onset, initial treatment, and radiotherapy were 26.2, 29.5, and 32.2 years, respectively. Radiotherapy was mainly applied for residual or recurrent tumors. The eosinophil count increased by more than 10% in 18 of the 20 patients. In most instances, irradiation was given through a single field with dosages ranging from 20 to 44 Gy. RESULTS: At the completion of radiotherapy, a marked response in tumor size was noted in all cases. The minimum follow-up was 48 months. Local control was obtained in 23 of 31 lesions (74.1%). At dosages of < or =25 Gy, 26-30 Gy, and > 30 Gy, local control was obtained in 2 of 8 (25.0%), 9 of 10 (90.0%), and 12 of 13 sites (92.3%), respectively. CONCLUSIONS: Radiotherapy is an effective treatment for Kimura's disease. This strongly suggests that no surgical procedure other than a biopsy should be carried out. The radiation field should be limited to the lesion and swelling of the adjacent lymph nodes as much as possible, with a optimum dosage of 26-30 Gy regardless of tumor size.

Adolescent↗

PubMed1998

Favorable strategy for the ostial lesion of the left anterior descending coronary artery: influence on narrowing of circumflex coronary artery.

We examined the effectiveness of Palmaz-Schatz (P-S) stent and directional coronary atherectomy (DCA) in ostial lesions of left anterior descending arteries (LAD). The P-S stent was implanted in 11 cases at LAD ostial lesions, and DCA was performed in 13 cases. Percent stenosis and vessel diameter at the target site and the ostium of the circumflex coronary artery (LCX) were measured before and after the procedure. The initial success rate was 100% in both groups. No major complication occurred. LAD ostial lesions were improved from 81.3+/-3.4% to -8.1+/-5.7% by P-S stent and from 82.8+/-2.6% to -2.7+/-3.9% by DCA. LCX ostial vessel diameter was not changed by DCA (from 3.0+/-0.2 mm to 3.1+/-0.3 mm); however, it was significantly decreased by P-S stent (from 2.9+/-0.2 mm to 2.6+/-0.2 mm, P < 0.01). When the angle of LAD and LCX was < or = 80 degrees from the view of RAO 30 degrees and Caudal 30 degrees, the LCX ostium was significantly narrowed by stenting at LAD ostium (P < 0.01). These findings indicate that both the P-S stent and DCA are effective and safe therapies for LAD ostial lesions in cases with LAD-LCX angle > 80 degrees. In cases with LAD-LCX angle < or = 80 degrees, however, DCA is a favored therapy rather than P-S stenting to avoid narrowing of the LCX ostium.

Atherectomy, Coronary↗

PubMed1998

Successful predilation of a resistant, heavily calcified lesion with cutting balloon for coronary stenting: a case report.

A 65-year-old man with a restenotic lesion of the mid LAD was scheduled for Wiktor stent placement. The IVUS revealed circumferential severe calcification. Two conventional, non-compliant angioplasty balloons inflated to high pressures failed to achieved sufficient dilatation and both ruptured. At this point, we selected high pressure inflation of the Cutting Balloon. The Cutting Balloon achieved adequate dilation for stenting and proved to be useful in predilating a circumferential, heavily calcified lesion.

Aged↗

PubMed1998

Effects of cyclosporin A and glucocorticosteroids on antigen-induced hypersensitivity to histamine in a guinea pig model of allergic rhinitis.

OBJECTIVE AND DESIGN: In an attempt to study the pathogenesis of mucosal hypersensitivity in allergic rhinitis, we investigated the suppressive effects of cyclosporin A (CyA) and glucocorticosteroids on ovalbumin (OA)-induced hypersensitivity to topical histamine challenge. MATERIALS: Actively sensitized Dunkin-Hartley guinea pigs. TREATMENT: OA and alum were applied to guinea pigs intraperitoneally 3 times at two-week intervals. After general sensitization, OA inhalation was performed every day for 6 days as topical sensitization. Before inhalation, treatment with CyA (50 mg/kg, p.o.), glucocorticosteroids (beclomethasone propionate (1.0 mg/kg, i.p.), fluticasone propionate (FP, 0.5 mg/kg, i.p.)) or vehicle were performed, and the sensitivity to histamine was measured before and after the inhalation. Moreover, in actively (general and topical) sensitized guinea pigs, FP (0.5 mg/kg, i.p.) was applied every day for 5 days and histamine sensitivity was evaluated before and after the application. RESULTS: We found that histamine sensitivity was significantly increased by nasal antigen challenge in this guinea pig model, and that the occurrence of histamine hypersensitivity was inhibited by the pretreatment with CyA and glucocorticosteroids. Although multiple administration of FP gradually reduced the histamine hypersensitivity according to the period of administration, it did not significantly alter the histamine hypersensitivity after the occurrence of hypersensitivity. CONCLUSION: It is concluded that CyA and glucocorticosteroids suppress antigen-induced histamine hypersensitivity in a guinea pig model of allergic rhinitis.

Administration, Inhalation↗

PubMed1998

Solitary fibrous tumor of the parotid gland extending to the parapharyngeal space.

Solitary fibrous tumors (SFT) arise in the pleura and less commonly in extrapleural sites. Head and neck regions have included the nose and paranasal sinuses, soft palate, epiglottis, thyroid, parotid and submandibular glands, as well as the infratemporal fossa and parapharyngeal space. We report a case of SFT arising from the parotid gland and extending to the parapharyngeal space. To our knowledge, this is the fourth case of SFT originating from the parotid gland and is the largest of its kind among the extrapleural lesions described. The characteristics revealed by computed tomography and magnetic resonance imaging are presented.

Fibroma↗

PubMed1998

Antigen-specific IgA response of NALT and cervical lymph node cells in antigen-primed rats.

Using antigen-primed rats, we examined the occurrence of antigen-specific antibody forming cells in mononuclear cells (MNC) of nasopharynx associated lymphoid tissues (NALT) and cervical lymph nodes (CLN) following in vitro stimulation with lipopolysaccharide (LPS), cytokines and antigen using the ELISPOT assay method. The rats were immunized with ovalubumin (OVA) by intraperitoneal injections, then by daily intranasal boostering for 2 weeks. In the nasal lavage fluid, the level of OVA-specific IgA antibody was higher and that of OVA-specific IgG antibody was lower than those antibodies in the serum. Following incubations. most of the IgA spot forming cells (SFC), but only 5 10% of IgG SFC were proved to be antigen-specific in the NALT and CLN MNCs. Following LPS stimulation, both the antigen-specific IgA and IgG SFCs increased 1.5- to 2-fold in the NALT MNC. However, following OVA stimulation, the antigen-specific IgA SFC increased 6- to 8-fold, which was remarkably higher than the antigen-specific IgG SFC. The changes of the antigen-specific immunoglobulin SFCs in the CLN MNC following the antigen stimulation were similar to those in the NALT MNC. These findings suggested that NALT might be one of the induction sites for antigen-specific IgA responses in rats.

Administration, Intranasal↗

PubMed1998

Expression of substance P (NK1) receptor mRNA in human nose.

In airway tissues, it has been suggested that substance P is the transmitter of afferent sensory nerves which respond to various irritants and may be involved in airway allergic reactions. Three classes of tachykinin receptor are currently recognized, denoted as NK1, NK2 and NK3, which exhibit preferential affinity for substance P, neurokinin A and neurokinin B, respectively. We used molecular probes to study the gene expression and distribution of NK1 receptor in human nose. Total RNA was isolated from human nasal mucosa and NK1 receptor mRNA was detected in these tissues by using reverse transcription and polymerase chain reaction (RT-PCR). For in situ hybridization study of human nasal mucosa, we utilized the PCR directly to incorporate a T7 RNA polymerase promoter sequence onto the NK1 receptor cDNA, and these PCR products were used as the DNA templates for producing digoxigenin-labelled anti-sense and sense RNA probes. These studies revealed that NK1 receptor mRNA was expressed in submucosal glands and airway epithelium. The results may have an important clinical implication, and also promote further investigation of gene regulation of NK1 receptor in health and disease.

Base Sequence↗

PubMed1998

Mucoepidermoid carcinoma of the larynx: a case which responded completely to radiotherapy and a review of the literature.

Most laryngeal cancers are squamous cell carcinomas, and adenocarcinomas account for < 1% of cancers of the larynx. Among them, mucoepidermoid carcinoma is extremely rare and there is little agreement about the treatment of this carcinoma. We encountered one patient with mucoepidermoid carcinoma of the bilateral vocal cords (T1bN0M0, Stage 1). For this, most investigators recommended a surgical procedure. However, because of his old age, the early stage and low grade of histopathology, we treated this patient with radiotherapy alone, delivered by accelerated hyperfractionation, which is a more effective strategy for treating radioresistant tumors than conventional irradiation. Following radiotherapy, the tumor disappeared and the patient has been alive and well for more than six years. An old patient with mucoepidermoid carcinoma of the larynx was successfully treated with radiotherapy alone.

Aged↗

PubMed1998

Effects of anti-IL-5 monoclonal antibody on the murine model of nasal allergy.

IL-5 is known to be closely related to the infiltration, activation and proliferation of eosinophils. In this study, we evaluated the in vivo effects of anti-IL-5 monoclonal antibody (mAb) in the murine model of nasal allergy. The mAb treatment inhibited the antigen-induced late phase eosinophilia, but had no effects on the number of basophilic cells. It also inhibited early phase nasal symptoms, and tended to inhibit histamine hypersensitivity. These findings suggest that IL-5 plays an important role in the pathogenesis of allergic nasal disorders.

Allergens↗

PubMed1998

A unique population of circulating autoantibodies promotes central nervous system remyelination.

In previous studies we demonstrated that the humoral immune response directed against unique central nervous system (CNS) antigens enhanced CNS remyelination in the Theiler's virus experimental model of multiple sclerosis (MS). To expand on this observation, a mouse IgM kappa monoclonal antibody (mAb) which enhances CNS remyelination, was raised against normal mouse spinal cord homogenate. Characterization of this mAb revealed that it is polyreactive towards variety of intracellular antigens but also reacts to an unidentified surface antigen on oligodendrocytes. The mAb is encoded by germline immunoglobulin genes without somatic mutations consistent with the observation that it is a natural autoantibody. Recently we generated another mouse IgM kappa mAb raised against normal spinal cord homogenate, which also promotes CNS remyelination. Further characterization revealed that both mAbs which promote remyelination have similar binding characteristics. Conventionally Abs which recognize normal CNS components, especially oligodendrocytes or myelin, have been considered to be a disease marker or be involved in the pathogenesis of MS. However, we have identified a unique population of circulating autoantibodies which are beneficial for myelin repair. Therefore this observation indicates the need to reevaluate autoantibody production against myelin components in CSF and blood as markers of disease activity versus repair in MS.

Animals↗

PubMed1998

The mobile hospital--an experimental telemedicine system for the early detection of disease.

To detect early disease, especially lung disease, we created a new telemedicine system, called the Mobile Hospital. It consists of a satellite or ground communication system using a large vehicle in which is installed a whole-body spiral computerized tomography scanner and a multimedia telecommunications system. The Mobile Hospital goes to small villages and carries out mass screening for early lung disease, especially lung cancer. It travelled over 8000 km from May 1996 to March 1997. In this period 6358 persons aged 50-85 years and younger heavy smokers were screened in the Matsumoto area. As a result, 37.7% of the subjects were suspected of having various latent lung diseases. The cost of medical treatment for the lung cancers detected by the Mobile Hospital was 44% of that for a conventional medical care group, and the length of hospital treatment with surgical operation was 30% of that of the conventional group.

Aged↗

PubMed1998

[Clinical study of hypopharyngeal carcinoma].

A clinical study was performed of 83 patients with hypopharyngeal cancer treated in the Sapporo Medical University Hospital from 1982 to 1995. Five-year cumulative survival rate was 34.9% in the whole group and 37.2% in the radical surgical and/or radiation treatment group. In the radiation treatment group, the patients with T1, T2, N0 or N1 stage disease, especially those whose original disease responded almost completely to 40Gy irradiation, showed high tumor control rates following full-dose irradiation with or without radical neck dissection. In the radical surgery group, the patients with T4 or N2 stage disease showed better prognosis than those in the radiation group. However, among the patients with N3 lymph node metastases, there were no long-term survivors in either the radiation or the surgery groups.

Adult↗

PubMed1998

[Obstructive sleep apnea in children with cerebral palsy].

To determine the etiology of obstructive sleep apnea (OSA) in children with cerebral palsy (CP), a survey using a questionnaire was conducted on parents of 233 CP children (1-5 years old, mean age: 2.7) and on those of 343 control children during a routine medical check-up at the age of three. The prevalence of habitual snoring and nasal obstruction was 63 and 20% in CP children, which were significantly higher than in control children. Sleep apnea episodes and stridor were noted in 19.7 and 15.4% of CP children. A screening sleep study was performed using Apnomonitor II and a pulseoximeter (Pulsox 5) in 48 CP children whose questionnaires revealed habitual snoring and sleep apnea, and it was found that 27 and 58% of the children had on apnea-hypopnea index (AHI) of greater than 5 and a low level of SaO2 (LSaO2) of less than 85%, respectively. When another 10 CP children visited our hospital for treatment of severe OSA, precise evaluations including pharyngeal pressure and fiberscopic examination during sleep as well as a sleep study using an inductive prezysmograph (Respigraph) were performed. Adenoid and/or tonsillar hypertrophy were noted in only 4 children, and the main cause of sleep apnea in the other 6 children was pharyngeal collapse at the lingual base. Their OSA was successfully treated by adenotonsillectomy in 2 children, adenotomy in 2 children, UPPP and lingualplasty in 1 child, tracheostomy in 2 children, and nasal CPAP in 1 child. Before treatment of OSA in CP children, precise evaluation is recommended in order to perform appropriate treatment.

Adenoidectomy↗

PubMed1998

[Results of a survey of the treatment policy for early stage tongue and oral floor cancer].

To realize the treatment policy for early stage oral cancer, a survey of 102 institutes in Japan was performed by questionnaire. A majority of the otolaryngologists preferred surgery for the treatment of T1N0 and T2N0 cases of oral cancer. The preferred method of treatment for the T1N0 cases was simple tumor resection and that for the T2N0 cases was extended tumor resection with plastic surgery, elective neck dissection and combined radio- and/or chemotherapy. A majority of the radiologists preferred brachytherapy for T1N0 and non-invasive T2N0 cases. For invasive cases of T2N0 oral cancer, radiologists preferred either surgical treatment or the combination of brachytherapy and external irradiation.

Adult↗

PubMed1998

Collaboration of national organizations and the legislative means to advance pulmonary rehabilitation.

Getting involved in the public policy process empowers health care professionals to help ensure the preservation of patient rights. An organization must form strong relationships with legislators using simple yet occasionally unconventional strategies. Too few patients currently have access to rehabilitative services. Passing national legislation promoting patient access to pulmonary rehabilitation will have a great impact by enabling more and more patients to take advantage of pulmonary rehabilitation programs because they are fully reimbursed.

Health Policy↗

PubMed1998

The effect of a cysteinyl leukotriene antagonist, ONO-1078 (pranlukast) on agonist- and antigen-induced nasal microvascular leakage in guinea pigs.

The in vivo model of nasal microvascular leakage was used for the nasal allergic challenge in ovalbumin (OA)-sensitized guinea pigs, or nasal stimulation with leukotriene D4 (LTD4) in non-sensitized animals. An intravenous injection of Evans blue dye was given as an index of nasal microvascular leakage. Following the nasal stimulation with LTD4, the concentration of dye in the nasal lavage fluid rapidly increased. Oral administration of ONO-1078 (pranlukast) (3-30 mg/kg) significantly inhibited the LTD4-induced nasal microvascular leakage. In OA-sensitized guinea pigs, the excretions of dye into nasal lavage fluid were recognized soon after the topical antigenic stimulation and continued for over 60 minutes. Oral administration of ONO-1078 (30 mg/kg) significantly inhibited the antigen-induced microvascular leakage. These results suggest that ONO-1078 may be of therapeutic use for nasal allergy.

Animals↗

PubMed1997

P/Q-type Ca2+ channel blocker omega-agatoxin IVA protects against brain injury after focal ischemia in rats.

Recently, P/Q-type Ca2+ channels have been shown to be involved in neurotransmission in the central nervous system in mammals. We evaluated the effects of the P/Q-type Ca2+ channel blocker omega-agatoxin IVA (omega-Aga-IVA) on brain edema formation and infarct size determined after 24 h of reperfusion following 1 h of middle cerebral artery (MCA) occlusion in rats. Intracerebroventricular (i.c.v.) treatment with omega-Aga-IVA significantly attenuated the postischemic increase of brain water content. omega-Aga-IVA also significantly reduced the size of the infarct area determined by triphenyltetrazolium chloride staining after 24 h of reperfusion. omega-Aga-IVA (30 pmol, i.c.v.), which exhibited a neuroprotective effect, had no significant effect on the magnitude of intra- and postischemic brain temperature when compared with vehicle-treated rats. This indicates that the postischemic neuroprotective effect of omega-Aga-IVA is produced by a direct and not an indirect effect via hypothermia. These results suggest that P/Q-type Ca2+ channels may be involved in the development of focal ischemic brain injury and that blockers of these channels may be therapeutically useful against ischemic injury.

Animals↗