PubMed Health⌕ Search

Biomedical subjects

Masayoshi Kobayashi

Publications and source records attributed to Masayoshi Kobayashi.

At least 19 recordsLinked to original sources
PubMed2006

Response of matrix metalloproteinase-9 to olfactory nerve injury.

Matrix metalloproteinases function in the remodeling of the extracellular matrix during growth and development as well as in injury and disease processes. We examined the role of matrix metalloproteinase-9 in a model of olfactory nerve injury in mice. We measured changes in matrix metalloproteinase-9 protein levels for up to 60 days following olfactory nerve transection. Matrix metalloproteinase-9 levels increased within hours after injury, peaked at day 1 and were elevated for approximately 2 weeks before returning to control levels over the 60-day time period. The increase in matrix metalloproteinase-9 was temporally associated with the degeneration of olfactory neurons that follows nerve transection and with increased gliosis. Our results demonstrate a temporal relationship between matrix metalloproteinase-9 elevation, degeneration of olfactory neurons and gliosis.

Animals↗
PubMed2006

Cross-cultural comparison of data using the odor stick identification test for Japanese (OSIT-J).

A new olfactory test, the odor stick identification test for Japanese (OSIT-J), has been developed in Japan. To determine if the OSIT-J would be effective cross-culturally, we administered the test to 52 US and 50 Japanese subjects reporting normal olfactory function. The average composite OSIT-J test score for US subjects was significantly lower (77%) than that for Japanese subjects (94%, P < 0.0001). Both US and Japanese subjects correctly identified eight of the 13 odorants included in the OSIT-J with scores of 80% or higher. However, for five odorants, the US subjects' scores fell below 80% and were consistently lower than Japanese subjects, presumably reflecting cultural differences in odor experience. Most of the US subjects found the OSIT-J to be easy, interesting, pleasant, and short in duration. Although the 13-odorant OSIT-J was found to be suitable for testing US populations, elimination of five test odorants that were unfamiliar to US subjects significantly enhanced the test's effectiveness. Findings from this study emphasize the importance of identifying test odorants that may have a cultural bias, a crucial issue when comparing data obtained from different smell tests used at smell and taste centers around the world.

Adult↗
PubMed2006

Biodegradation and bioabsorption innovation of the functionally graded bovine bone-originated apatite with blood permeability.

Bioabsorbable and functionally graded apatite (fg-HAp) ceramics were designed using bovine bone by the calcination and partial dissolution-precipitation methods. The fg-HAp ceramics that were developed had gradual distributions of the degree of crystallinity and the grain size of single-phase hydroxyapatite from the surface layer of the pore wall to the bulk structure region. Calcination at 1073 K gave a specific surface area of 30 m2 x g-1 and porosities of 60-80%. The pore structure of the fg-HAp was classified into two regions: a macro-pore region (100-600 microm) originating from spongy bone and a micro-pore region (10-160 nm) related to body fluid permeation and blood permeability. By implantation in subcutaneous tissue of rat, it was confirmed that body fluid permeated the bulk region of the fg-HAp ceramics through the micro-pores. The volumetric populations occupied by body fluid were 60% at 4 weeks and 68% at 8 weeks in the ceramics explants, indicating drastic bioabsorption, although the body fluid was found to be immunopositive for an albumin as the main serum protein in blood. On the fg-HAp ceramics developed here, the bioabsorption rate could be controlled by careful selection of the calcination temperature. These ceramics can be applied as new biomimetic ceramics exhibiting surface and bulk degradations and cellular absorption by giant cells.

Adsorption↗
PubMed2006

Current pathological and clinical aspects of Buerger's disease in Japan.

Since Buerger's disease was first described by Leo Buerger in 1908, many authors have discussed whether it indeed exists and, if so, is a definite clinical entity. Today, Buerger's disease is accepted as a definite vascular disease with a typical clinical picture, natural history, and histopathology; however, the diagnosis of Buerger's disease has been controversial, and the etiology of this vascular occlusive disease has remained unknown because many authors in different countries have their own criteria. Besides, patients with this disease have decreased in number even in Japan, while there has been no change in the number of arteriosclerosis obliterans patients. Currently, only one or two new patients per year are encountered at our outpatient clinic. The purpose of this review is to examine the current epidemiological, pathological, and clinical aspects of Buerger's disease in Japan based on the 222 patient files of our department between 1980 and 2000 and to discuss the pathogenesis, clinical presentation, and various treatment modalities.

Adolescent↗
PubMed2006

Abrading increases oxygen and hardness of titanium surface.

CP Ti was mirror-polished and then abraded with waterproof SiC papers of two different grit sizes: 16 and 3 microm. As-polished and abraded surfaces were characterized by means of EPMA, XPS, XRD, and hardness test. Oxygen in the mirror-polished surface was uniformly distributed at the lowest level. Comparatively, abrading with SiC papers increased the surface oxygen amount and hardness. Owing to its excellent abrasivity, the coarse grit efficiently scratched the surface and hindered the regenerated oxide film from growing thick, but allowed only the metal-oxide interfacial gradient zone to extend. But, the fine grit merely rubbed the surface and allowed both the oxide film and interfacial zone to extend. Further, the surface appeared to be lightly yellow-colored, suggesting that the oxide film was thicker, probably within 10 nm, than the nominal one. When compared with the bulk, the interfacial zone was rich in oxygen and therefore subjected to high coherency strain, which was introduced to relieve the great lattice mismatch between the outer and inner layers of titanium substrate. Effects of solute oxygen hardening and strain hardening were speculated to be responsible for the surface hardening of both SiC-abraded surfaces. In conclusion, abrading with a coarse grit led to accumulation of a high, non-uniform strain in the titanium substrate, thereby hardening the surface further.

Analysis of Variance↗
PubMed2005

Effects of exercise intensity, posture, pressure on the back and ambient temperature on palmar sweating responses due to handgrip exercises in humans.

We have, by using newly developed ratemeters, attempted to examine the effects of exercise intensity, posture, pressure on the skin of the back, and ambient hyperthermic conditions (approximately 30 degrees C) on the 5-s handgrip exercise-mediated responses of active palmar sweating in humans. Thirty-five right-handed male (n=5) and female (n=30) volunteer students (20.2+/-1.3 years old) participated in the present study. Oral explanation of only the isometric handgrip exercise (IHG) caused a rapid and oscillatory response (pre-operational) of active palmar sweating in almost all subjects (10 of 14 subjects). Performing the IHG for 5-s caused a significant increase in active sweating rate (operation-mediated response) in both ipsi- and contra-lateral palmar surfaces of the thumbs of all subjects. The operation-mediated responses of active palmar sweating to the IHG were reproducible, resulting in no habituation. The increase of operation-mediated responses to the IHG was dependent upon exercise intensity (100-25% maximal voluntary contractions). The IHG-mediated ipsi- and contra-lateral responses of active palmar sweating were significantly decreased by changing the body posture from a seated to a supine position or by pressing the skin of the back. Ambient hyperthermic conditions (approximately 30 degrees C) for 60 min also resulted in a significant decrease in the back-pressure-dependent reduction of the operation-mediated responses of active palmar sweating to the IHG. In conclusion, in order to optimize the precision and reproducibility of clinical tests involving palmar sweating responses, it is important that subjects maintain a constant handgrip force and posture and that ambient temperature be kept under normothermic conditions.

Adult↗
PubMed2005

Hydrophilic statin suppresses vein graft intimal hyperplasia via endothelial cell-tropic Rho-kinase inhibition.

BACKGROUND: Recent studies suggest that statins can protect the vasculature in a manner that is independent of their lipid-lowering activity through inhibition of the small guanosine triphosphate-binding protein, Rho, and Rho-associated kinase. Little information is available on the inhibitory effect of statins on vein graft intimal hyperplasia, the main cause of late graft failure after bypass grafting. We therefore examined the effects of a hydrophilic statin on vein graft intimal hyperplasia in vivo and Rho-kinase activity in vitro. METHODS: In the first experiment, rabbits were randomized to a control group (n = 7) that was fed regular rabbit chow or to a pravastatin group (n = 7) that was fed regular rabbit chow supplemented with 10 mg/kg pravastatin sodium. The branches of the jugular vein were ligated and an approximately 3-cm segment of the jugular vein was taken for an autologous reversed-vein graft. The carotid artery was cut and replaced with the harvested autologous jugular vein. At 2 and 4 weeks after the operation, vein grafts in both groups were harvested, and intimal hyperplasia of the vein grafts was assessed. In the second experiment, human umbilical vein endothelial cells and vascular smooth muscle cells were cultured and then treated with 1 micromol/L and 30 micromol/L pravastatin for 24 hours and harvested. Immunoblotting was performed on the resulting precipitates. Quantitative evaluation of phosphorylated myosin binding subunit and endothelial nitric oxide synthase was performed by densitometric analysis. RESULTS: We demonstrated that oral administration of the hydrophilic statin pravastatin to normocholesterolemic rabbits inhibited intimal hyperplasia of carotid interposition-reversed jugular vein grafts 4 weeks after implantation (pravastatin group, 39.5 +/- 3.5 microm vs control group, 64.0 +/- 7.1 microm; n = 7; P < .05) and suppressed cell proliferation and apoptosis in the neointima 2 weeks after implantation. In addition, we found that pravastatin inhibited Rho-kinase activity and accelerated endothelial nitric oxide synthase expression in human umbilical vein endothelial cells but did not inhibit Rho-kinase activity in vascular smooth muscle cells. CONCLUSIONS: These novel findings clearly demonstrate that a hydrophilic statin can suppress intimal hyperplasia of the vein graft in vivo and also show endothelial cell-tropic inhibition of Rho-kinase in vitro. Furthermore, these results strongly support the clinical use of hydrophilic statins to prevent intimal hyperplasia of the vein graft after bypass grafting. CLINICAL RELEVANCE: Late graft failure caused by neointimal hyperplasia limits the efficacy of vein grafting. Various treatments were examined to reduce neointimal hyperplasia, but a standard clinical treatment has not yet been established. We report here the inhibitory effect of pravastatin on the development of vein graft intimal hyperplasia. In addition, we demonstrate that pravastatin showed endothelial cell-tropic benefits through both the inhibition of Rho-kinase activity and acceleration of eNOS expression in vitro. Because the clinical benefits and safety of pravastatin have been established to a certain extent through long-term clinical usage, pravastatin may soon become standard treatment after vein bypass grafting.

Animals↗
PubMed2005

[Safety and usefulness of the long-term intranasal topical treatment with steroids for olfactory dysfunction].

Intranasal topical steroids are commonly used for the treatment of olfactory dysfunction. Although the side effects are considered to be minimal, these have not been studied in detail. We examined the side effects of intranasal topical treatment with steroids in patients with olfactory dysfunction. We treated 62 patients with intranasal topical application of 0.1% betamethasone sodium phosphate (Rinderone) administered to the olfactory clefts. After treatment for 1 or 2 months, serum ACTH or cortisol was reduced in 42 (68% of total) patients, however, no clinical symptoms associated with steroid side effects were observed. The treatment was discontinued in 8 of these patients, who elected to withdraw from the treatment. In these patients, the serum ACTH or cortisol returned to normal a month after stopping the treatment. In the remaining 34 patients, the topical treatment was continued and in only 4 of these patients, minor steroid-associated side effects such as the sensation of facial swelling and facial hair thickening, appeared 2-5 months after beginning the treatment. These side effects disappeared within a month after stopping the treatment. Regarding the therapeutic efficacy, in 18 (78%) of the 23 patients who continued treatment for an average period of 5 months, steroid treatment significantly improved their olfactory dysfunction. In conclusion, although it is important to consider the potential side effects of long-term intranasal topical treatment with steroids for olfactory dysfunction, this treatment is a highly effective method against olfactory dysfunction with minimal side effects.

Administration, Intranasal↗
PubMed2004

Molecular evaluation of endothelial progenitor cells in patients with ischemic limbs: therapeutic effect by stem cell transplantation.

OBJECTIVE: Although some patients with limb ischemia have recently undergone therapeutic angiogenesis by cell transplantation, their angiogenic potential has not been well characterized. It is also important to evaluate endothelial progenitor cell (EPC) contents in different stem cell sources to choose the best material for therapeutic angiogenesis. METHODS AND RESULTS: We quantitated the mRNA expression of EPC-specific molecules (eg, Flk-1, Flt-1, CD133, VE-cadherin, etc) in bone marrow-derived or peripheral blood-derived mononuclear cells obtained from patients with ischemic limbs, using real-time reverse-transcription polymerase chain reaction technique. The mRNA expression level of EPC markers was significantly lower in the patients than in healthy controls, which was consistent with results of flow cytometric analysis. However, the implantation of autologous bone marrow mononuclear cells increased the circulating EPCs in the peripheral blood of patients. We furthermore revealed the different expression pattern of EPC markers in possible sources for stem cell transplantation, including normal bone marrow, peripheral blood obtained from recombinant granulocyte colony-stimulating factor-treated donor, and umbilical cord blood. CONCLUSIONS: Patients with peripheral obstructive arterial diseases may have lower angiogenic potential because of decreased expression of EPC specific molecules in their marrow and blood. Therapeutic angiogenesis by transplantation of autologous marrow mononuclear cells increased circulating EPCs in the patients and improved ischemic symptoms.

AC133 Antigen↗
PubMed2004

Target site of inhibition of baroreflex vagal bradycardia by nasal stimulation.

We have previously reported that stimulation of nasal mucosa inhibits baroreflex vagal bradycardia (BVB) and this inhibition was mediated exclusively by the trigeminal nerve, and occurred principally at pontomedullary level. In this study, to identify the target site of the inhibition, several types of experiments were conducted in chloralose-urethane-anesthetized, beta-adrenergic receptor-blocked rats. Afferent discharges in the ethmoidal nerve (EN5) were increased in response to nasal stimulation by smoke, and electrical stimulation of the EN5 suppressed BVB induced by electrical stimulation of the aortic depressor nerve (ADN). Electrical stimulation of the EN5 inhibited vagal bradycardia evoked by either electrical or chemical stimulation of the nucleus tractus solitarius (NTS), while it rather facilitated bradycardia by stimulation of the nucleus ambiguus (NA) region. Microstimulation of the NTS induced antidromic compound spike potential along the ADN but this was not affected by stimulation of the EN5. ADN-evoked field potentials and unitary responses of neurons in the NTS were suppressed by stimulation of the EN5. These results suggested that barosensitive neurons in the NTS are the major target sites of inhibition of BVB by nasal stimulation in rats.

Action Potentials↗
PubMed2004

Subcutaneous tissue release of amikacin from a fibrin glue/polyurethane graft.

We investigated whether fibrin glue (FG) might be useful as a carrier of amikacin (AMK) for prevention of local graft infection. After AMK (4.0 mg)-treated FG (AMK-FG) polyurethane grafts were implanted subcutaneously in the anterior abdominal region of Sprague-Dawley rats, AMK concentrations in tissues surrounding the implantation sites were compared over time with concentrations at the same sites in rats given an intravenous injection of AMK (4.0 mg). In the injection group, AMK concentrations in serum were detectable only for 4 h, whereas AMK released from AMK-FG grafts remained detectable over 24 h. Until 4 h after implantation, AMK concentrations in tissues near implantation sites were significantly higher in the AMK-FG graft group than in the injection group; peak local concentrations during that time were 210 times higher for the AMK-FG graft group than for the injection group. Areas under the tissue concentration-time curve (AUC) for AMK were 171 microg x h/g and 1.35 microg x h/g in the AMK-FG graft and injection groups, respectively. FG therefore was considered to control release of AMK and to maintain a high AMK concentration in tissues surrounding the implantation site. Thus, AMK-FG polyurethane graft delivery may be useful in preventing local infection by local delivery of AMK.

Abdomen↗
PubMed2004

External iliac venous aneurysm in a pregnant woman: a case report.

We report an external iliac venous aneurysm in a young pregnant woman who was diagnosed incidentally by ultrasound scanning. The aneurysm was successfully treated by tangential aneurysmectomy and lateral venorrhaphy. Primary iliac venous aneurysm is a rare vascular abnormality. The clinical significance of the disease is unknown. However, embolism, rupture, and thrombosis might occur as they can occur with popliteal venous aneurysm. In fact, three of four reported patients with iliac venous aneurysms had a thromboembolic event. For those reasons, prophylactic treatment is indicated. This is the first patient with an iliac venous aneurysm to be diagnosed without complication.

Adult↗
PubMed2004

Microbial xylitol production from corn cobs using Candida magnoliae.

Microbial production of xylitol from corn cobs using Candida magnoliae was experimentally investigated. Approximately 25 g-xylose/l solution was obtained from 100 g-corn cobs/l solution by hydrolysis using 1.0% sulfuric acid at 121 degrees C for 60 min. To remove inhibitors from the hydrolysates, charcoal pellets were found to be effective in selectively removing the inhibitors from the hydrolysates without affecting xylose concentration. C. magnoliae was successfully cultivated using the treated corn cob hydrolysate, resulting in the production of 18.7 g-xylitol/l from 25 g-xylose/l within 36 h.

Journal Article↗
PubMed2004

Suitability of the odor stick identification test for the Japanese in patients suffering from olfactory disturbance.

We studied the suitability of the Odor Stick Identification Test for the Japanese (OSIT-J) in patients suffering from olfactory disturbance. In 120 patients with olfactory disturbance (age range 12-85 years) there were statistically significant correlations between the odor identification rate on the OSIT-J, the results of the Japanese standardized olfactory test (T&T olfactometry) and subjective symptom scores. In every patient treated for olfactory disturbance, the OSIT-J reflected the grade of recovery from the olfactory disturbance as determined by means of T&T olfactometry. The odor identification rate on the OSIT-J also correlated significantly with the results of the i.v. Alinamin test. Regarding the rate of correct recognition of odors on the OSIT-J, menthol and curry odors were recognized with a high rate and orange and wood odors with a low rate. Although the OSIT-J includes 13 kinds of odorants, the number of odorants used can be reduced to a minimum of 5 as the results obtained with this reduced form of the OSIT-J also correlated with the results of T&T olfactometry and the subjective symptom scores as well as with the results obtained with the 13-odorant OSIT-J. We conclude that the OSIT-J is suitable not only as a screening test for olfactory disturbance but also for practical use in clinical otorhinolaryngology.

Adolescent↗
PubMed2004

Long term outcome of femoropopliteal bypass for claudication and critical ischemia.

We performed 167 femoropopliteal bypass surgeries in 151 patients (95 patients underwent above-knee bypass and 56 below-knee bypass) from December 1985 to December 2000 with the use of prosthetic graft or autologous vein graft. We compared primary patency rates between age, sex, graft material, distal anastomotic site and severity of ischemia, considering their survival rates to elucidate the long-term outcome of above-knee and below-knee femoropopliteal bypass. The 10 year patency rate for above-knee bypass was 47.4%, compared to 36.9% for below-knee ( p < 0.01). Better results were found after bypass surgery for claudicants than for critical ischemia ( p < 0.05). With regard to graft material and age categories, there were unexpectedly no statistical differences in either above-knee or below-knee anastomosis. The survival rate at 10 years in claudicants was 51.2%, compared to 15.9% with critical ischemia ( p < 0.01). Mortality was much influenced by ischemic heart disease ( p < 0.002) and the age of patient ( p < 0.05). The results after above-knee bypass had comparable patency, whereas the results after below-knee bypass were disappointing. Below-knee arterial reconstruction for claudicants should be carefully considered and might be recommended only to patients with critical ischemia.

Age Factors↗
PubMed2004

[A case report on congenital anosmia].

We report 2 cases of congenital anosmia, in a 13-year-old girl and the other in a 10-year-old boy. They reported having no concept of "smell". The girl has no complications but the boy has congenital microphthalmia and is completely blind. They showed scale-out results on both T & T olfactometry and intravenous Alinamin test. Brain MRI detected hypoplasia or lack of the olfactory bulbs, tracts, and olfactory sulci in the frontal lobe of the brain in both patients. Neither had endocrinal dysfunction. In the boy, we biopsied the nasal mucosa in the olfactory cleft and found it had no olfactory epithelial cells at all. We found MRI to be the most useful imaging for diagnosing congenital olfactory disturbance.

Adolescent↗
PubMed2004

Morphological and chemical characterizations of the interface of a hydroxyapatite-coated implant.

The present study aimed at morphological and chemical characterization of the coating-substrate interface of a commercially available dental implant coated with plasma-sprayed hydroxyapatite (HA). For this purpose, elements in the chemically and mechanically exposed substrate surfaces were analyzed by EPMA and XPS. A thin titanium oxide film containing Ca and P was found at the interface. When the implant was subjected to mechanical stress, a mixed mode of cohesive and interfacial fractures occurred. The cohesive fracture was due to separation of the oxide film from the substrate, while the interfacial fracture was due to exfoliation of the coating from the oxide film bonded to the substrate. Analysis showed diffusion of Ca into the metal substrate, hence indicating the presence of chemical bond at the interface. However, mechanical interlocking seemed to play the major role in the interfacial bond.

Calcium↗