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Biomedical subjects

M Sunakawa

Publications and source records attributed to M Sunakawa.

At least 19 recordsLinked to original sources
PubMed2002

Colonization of denture plaque by respiratory pathogens in dependent elderly.

OBJECTIVES: Recently, there has been a resurgence of interest in the interactions between oral conditions and a number of prevalent systemic diseases. The morbidity and mortality of the dependent elderly that result from aspiration pneumonia have been recognized as a major geriatric health problem. The purpose of this study was to gain more information on the microflora of plaque on dentures and to assess the existence of oral infectious pathogens potentially causing the respiratory disease in the dependent elderly. SUBJECTS AND METHODS: The denture bacterial flora of 50 dependent elderly were examined to identify microorganisms by the culture method. RESULTS: 18 species of microorganisms were detected in denture plaque in this study. A variety of pathogens with the potential to cause respiratory infection pathogens colonized on the dentures of dependent elderly. CONCLUSION: The results of the present study revealed that bacteria that commonly cause respiratory infection colonized on the dentures of dependent elderly, suggesting that denture plaque may function as a reservoir of potential respiratory pathogens to facilitate colonization on the oropharynx.

Aged↗
PubMed2000

Pulsed Nd:YAG laser irradiation of the tooth pulp in the cat: I. Effect of spot lasing.

BACKGROUND AND OBJECTIVE: The purpose of the present study was to evaluate physiologically pulpal nerve responses and to elucidate histopathologically the pulp tissue reactions to "spot irradiation" with a pulsed Nd:YAG laser. STUDY DESIGN/MATERIALS AND METHODS: Antidromic compound action potentials and the pulpal blood flow (PBF) were recorded from the canine tooth of a sodium pentobarbitone-anesthetized cat. The laser irradiation-induced pulp tissue changes were histologically investigated. RESULTS: The coronal antidromic compound action potentials disappeared in all the teeth tested during lasing, and the time needed to erase them was significantly shortened with increases in lasing power (P < 0.05). The radicular PBF increased when spot irradiation was performed, and the coronal PBF also temporarily increased with low-powered lasing. Histologic investigation revealed that spot irradiation with the laser produced severe damage in the pulp tissue in a dose-dependent manner. CONCLUSION: The present study suggests that spot irradiation with a pulsed Nd:YAG laser risks producing nerve injury and irreversible tissue damage in the pulp with lasing for the purpose of desensitizing hypersensitive dentin.

Action Potentials↗
PubMed2000

Pulsed Nd:YAG laser irradiation of the tooth pulp in the cat: II. Effect of scanning lasing.

BACKGROUND AND OBJECTIVE: The purpose of the present study was to assess whether "scan irradiation" with a pulsed Nd:YAG laser could produce changes in intrapulpal nerve activities and pulpal blood flow and to investigate whether it would cause tissue damage in the pulp. STUDY DESIGN/MATERIALS AND METHODS: The pulsed Nd:YAG laser was used to irradiate, in a scanning manner, the canine tooth pulp in sodium pentobarbitone anesthetized cats. The compound action potentials and spike response in the functional single afferent nerve fibers were recorded while responding to various external stimuli applied to the exposed dentin. Histologic observation was performed to detect lasing-induced tissue changes. RESULTS: Pulpal compound action potentials evoked by various external stimuli were significantly reduced (P < 0.05) and unit firings were observed in both functional single A delta- and C-fibers during irradiation. Unit responses to external mechanical stimulation of the dentin completely disappeared after "scan irradiation" with the pulsed Nd:YAG laser. Histologic observation revealed that irradiation with the laser produced tissue damage in the pulp. CONCLUSION: "Scan irradiation" with the pulsed Nd:YAG laser of cat's teeth produced alterations in the intrapulpal nerve activities, as well as caused tissue damage in the pulp.

Animals↗
PubMed2000

Increased blood flow and nerve firing in the cat canine tooth in response to stimulation of the second premolar pulp.

Mustard oil or mechanical stimulation was applied to maxillary second premolar tooth pulps and pulpal blood flow and or intradental nerve activity in the ipsilateral canine tooth were recorded in the cat. Mustard oil application to the second premolar pulp significantly increased blood flow in the canine tooth pulp to 162.0+/-65.8% (n = 16) of the prestimulation flow compared to control data obtained with application of mineral oil (107.0+/-5.1%, n = 6) (Mann-Whitney U-test, p = 0.0009). Sectioning of the infraorbital nerve and its branches on the experimental side (n = 4) did not affect this increase in pulpal blood flow. The paraperiosteal injection of 2% lidocaine (1.0 ml) without vasoconstrictor significantly inhibited the increase in canine pulpal blood flow induced by mustard oil application to the second premolar pulp (109.8+/-6.8% of the prestimulation level, n = 7) (Mann-Whitney U-test, p = 0.0013). Sporadic firing or sometimes bursts of action potentials in the canine pulp nerves were recorded during and/or after the mustard oil application to the second premolar pulp in three of 16 cases. Four single pulp nerve units firing in synchrony with the mechanical stimulation of the second premolar pulp were recorded in two of eight canines, which substantiated the existence of branched afferents innervating both teeth. These findings suggest that stimulation of the second premolar pulp may induce axon reflex-related vasodilation and intradental nerve firing in the canine pulp via branched afferent fibres innervating both the second premolar and canine teeth.

Animals↗
PubMed1999

Jaw electromyographic activity induced by the application of algesic chemicals to the rat tooth pulp.

The aim of this study was to determine if the application of mustard oil (MO), a small-fiber excitant and inflammatory irritant, or other algesic chemicals (capsaicin, CAP, and bradykinin, BK) to the rat maxillary molar tooth pulp induces electromyographic (EMG) activity of the masseter and digastric muscles, and also to determine if endogenous opioid mechanisms may be involved in any documented EMG changes. Application of MO to the tooth pulp induced a significant increase in EMG activity of the ipsilateral masseter up to 30 min. The application of mineral oil to the pulp or MO application to the pulp-extirpated tooth did not induce any significant EMG increases. The application of CAP or BK to the pulp in contrast had much weaker effects on EMG activity of the jaw muscles. CAP produced a small but prolonged increase in masseter EMG activity, and BK induced a short-lasting increase in digastric EMG activity. The systemic administration of the opiate antagonist naloxone significantly reactivated (i.e. rekindled) the EMG response evoked by MO application to the pulp. Naloxone did not produce any such significant rekindling effect on EMG activity following CAP, BK or mineral oil application to the pulp or following MO application to the pulp-extirpated tooth. The MO, BK and especially CAP groups showed histological evidence of vasodilatation and polymorphonuclear leukocyte infiltration in the pulp tissue and a significant increase in plasma extravasation of Evans Blue dye, whereas mineral oil did not induce these changes. These findings suggest that pulp afferent inputs to the central nervous system evoked by BK. CAP and especially MO may induce enhanced jaw muscle activity. In addition, the naloxone data suggest that an opioid suppresive mechanism may be induced by the pulpal afferent inputs evoked by MO, and may serve to limit the jaw muscle activity elicited by these inputs.

Animals↗
PubMed1999

[A case of Churg-Strauss syndrome presented as right thalamic hemorrhage].

Intracerebral hemorrhage is an uncommon sequel of Churg-Strauss syndrome (CSS). We report the first case of CSS accompanied by right thalamic hemorrhage. The patient was 59-year-old male who experienced a sudden onset of left hemiplegia. Magnetic resonance imaging of the brain revealed right thalamic hemorrhage. Although several reports had pointed out a close relationship between hypertension and cerebral hemorrhage in patients with CSS, this patient had no apparent prior history of hypertension. The cause of thalamic hemorrhage in this patient might be probably due to cerebral vasculitis and an effect of abnormal coagulation and fibrinolytic agents.

Cerebral Hemorrhage↗
PubMed1997

[The effect of hyperbaric oxygenation on nitrite and nitrate production in rats treated with endotoxin].

The effect of hyperbaric oxygenation (HBO; 3 ATA, 90 min) on production of stable endproducts of nitric oxide (NO); nitrite (NO2-) and nitrate (NO3-), in plasma was studied in anesthetized rats treated with lipopolysaccharide (LPS). Intravenous injection of LPS (1 mg.kg-1) increased NO2-/NO3- production in plasma significantly 5-6 hrs after treatment, compared with non-treated rats. Production of NO2-/NO3- was not influenced by HBO performed 3 hrs after LPS injection. HBO performed 1 hr after LPS treatment, however, depressed NO2-/NO3- production significantly, compared with HBO performed 3 hrs after LPS, although NO2- production remained increased. These data suggest that HBO may influence the NO2-/NO3- production in NO producing processes in rats treated with LPS.

Anesthesia↗
PubMed1995

Three groups of afferent pulpal feline nerve fibres show different electrophysiological response properties.

Responses were recorded, after the application of four types of stimuli (slow or rapid elevation of temperature, hydrostatic negative pressure through thin dentine, and bradykinin directly applied to exposed pulp), from functional single fibres innervating the cat lower canine tooth pulp, dissected from the inferior alveolar nerve. A total of 278 single pulpal fibres were isolated. A fibres (n = 220) were divided into two groups: one (FA; fast A fibre, n = 160) consisting of those whose conduction velocities (CVs) were more than 2 m/s both inside and outside the tooth pulp, and the other (SA delta; slow A delta fibre, n = 60) consisting of those whose intrapulpal CVs were less than 2 m/s and extrapulpal CVs greater than 2 m/s. Fifty eight C fibres (C) were also found. None of FA, 40% of SA delta and 52% of C responded to continuous heat. None of C, 47% of FA and 45% of SA delta responded to rapid elevation of temperature. None of C, 20% of FA and 20% of SA delta responded to hydrostatic pressure. None of FA, 83% of SA delta and all of C responded to bradykinin. It was found that 21 of 60 SA delta responded to both types of stimuli that reportedly activate only A (rapid heat and hydrostatic negative pressure) or C (continuous slow heat and bradykinin) nerve fibres and that 29 SA delta responded to slow heating and/or bradykinin, similar to C fibres.

Animals↗
PubMed1992

[Plasma fibrinopeptide A, fibrinopeptide B beta 15-42 and 4 other coagulation factors levels in patients with diabetic retinopathy].

Fibrinopeptide A (FPA), fibrinopeptide B beta 15-42 (FPB beta 15-42) and other coagulation factors (anti-thrombin III, thrombin-antithrombin complex, alpha 2-macroglobulin, plasmin inhibitor complex) were measured in the plasma of 101 patients with diabetes mellitus (DM). The levels in 80 healthy adults were also measured for comparative purposes. The mean levels of FPA, FPB beta 15-42 and the other 4 coagulation factors in the DM patients were significantly higher than in the controls (p < 0.05). The mean levels of FPA and FPB beta 15-42 in patients with diabetic retinopathy (DR) were higher than in those without DR, that is in those with proliferative diabetic retinopathy (PDR) higher than in those with simple diabetic retinopathy (SDR). In patients after panretinal photocoagulation (PRP), the mean level of FPA was higher and that of FPB beta 15-42 was lower than in patients before PRP. In the SDR group, the level of FPB beta 15-42 was significantly correlated with the progression of diabetic retinopathy. We suggest that there was a close correlation between plasma FPA and FPB beta 15-42 levels and activity or progression of disease, and that the investigation of these levels may be useful for the judging of prognosis or effect of therapies of diabetic retinopathy.

Blood Coagulation Factors↗
PubMed1991

Treatment of pars planitis with cryotherapy.

Cryotherapy was performed on 28 eyes exhibiting massive exudates (snowbank) over the pars plana and the ora serrata. Twenty-six patients ranging in age from 8 to 52 years were treated and then followed up for a median of 34 months. Eleven eyes needed repeat cryotherapy. After cryotherapy, retinal vasculitis and vitreous opacities decreased in most eyes. Although only 3 of 5 eyes with a snowbank greater than 90 degrees and treated over 1 year from the onset achieved visual acuity of 20/25 or better, all 12 eyes with a snowbank smaller than 60 degrees and treated within 3 months after the onset maintained a visual acuity of 20/25 or better. The prognosis was not different from the 20 eyes that received systemic steroid treatment and the 8 eyes that received no systemic steroids. We recommend cryotherapy as the primary treatment for pars planitis with a snowbank.

Adolescent↗
PubMed1991

[Response properties of pulpal nerve fibers with different conduction velocities].

Tapering and branching of the nerve fibers cause the conduction velocity (CV) along the axon to be unequal. The purpose of this study was to investigate the response properties of the myelinated and unmyelinated nerve fibers in the cat tooth pulp. Electrophysiological recordings were made from the functional single fibers innervating the lower canine tooth pulp in 25 adult cats anesthetized with pentobarbital sodium after the application of four types of stimuli to the canine tooth. A total of 272 single pulpal nerve fibers was identified. A-fibers (n = 215) were divided into two groups: One (Ac, n = 55) consisting of the fibers whose intrapulpal CVs were less than 2 m/s and the extra-pulpal CVs of more than 2 m/s, and the other (At, n = 160) consisting of the fibers whose CVs were more than 2m/s both inside and outside the tooth pulp. Fifty-seven C-fibers (C) were also found. None of C, 47% of At and 46% of Ac responded to the rapid elevation of the temperature. None of At, 38% of Ac and 53% of C responded to the continuous heat. None of C, 20% of At and 20% of Ac responded to the hydrostatic pressure. None of At, 86% of Ac and all of C responded to bradykinin. These results suggest that the functional difference between the pulpal A-and C-fibers is not clear and that the Ac-fibers may complicate the dental and pulpal pain.

Animals↗
PubMed1989

Evaluation of tissue perfusion in ischemic legs of dogs by CO2 clearance rate.

Improvement in tissue perfusion following surgically induced ischemia in limbs of dogs was experimentally evaluated to clarify the improvement of hemodynamics following walking exercise in chronic, peripheral arterial occlusive diseases. With the use of a computer system in conjunction with medical mass spectrometry, the local tissue perfusion rate was calculated on the basis of the clearance curve of tissue partial pressure of CO2 following electrical stimulation of the ischemic leg to simulate exercise. Ischemia was created in the leg by ligation of the proximal and peripheral arteries. In one month, intermittent claudication improved in accordance with improvement in muscle tissue perfusion. Angiographic evidence of distal runoff became visible six months after surgery, indicating that tissue perfusion played an important role in peripheral hemodynamics. The local tissue perfusion rate improved from 9.51 +/- 2.62 ml/100 g/min to 12.41 +/- 2.42 in one month, to 14.59 +/- 3.19 in three months, to 15.11 +/- 3.24 in six months and to 17.19 +/- 2.63 in twelve months. The improvement of ischemic symptoms following long-term exercise is attributed to improvements in tissue perfusion or collateral circulation.

Angiography↗
PubMed1989

[Response properties of the neurons in the cervical cord to stimulation of the inferior alveolar nerve in the cat].

The purpose of this study was to investigate the neuronal mechanisms of the clinical symptoms of unusual muscle stiffness and/or pain in the neck and shoulder sometimes observed in patients suffering from chronic pulpal or periodontal diseases. Physiological properties of the neurons responding to the inferior alveolar nerve stimulation (inferior alveolar nerve driven-neurons: IANDNs) were studied by recording single unit activities in the upper cervical cord in cats anesthetized with alpha-chloralose. The results were as follows: (1) IANDNs were widely distributed from the dorsal horn to the ventral horn in the gray matter of the cervical cord (C2 and C3). (2) IANDNs were subdivided into two types of neurons based on the latencies of the spike responses: fast-type (F-type) (n = 60) and slow-type (S-type) (n = 101). (3) Two possible pathways from the inferior alveolar nerve to the cervical spinal cord participating in these spike responses were assumed: one was through the trigeminal spinal nucleus and the other through Probst's tract by way of the trigeminal mesencephalic nucleus. These results suggest that the impulses originating from dental inflammatory loci might drive IANDNs in C2 or C3 and that their activities may evoke contraction of the neck muscles, resulting in their stiffness and cervical back pain.

Animals↗
PubMed1989

High-dose intravenous gammaglobulin therapy for uveitis.

One of my patients had severe uveitis with retinal phlebitis, retinal exudation and vitreous bleeding against high-dose steroid therapy. After high-dose intravenous gammaglobulin therapy was applied, retinal exudation and phlebitis subsided and visual acuity increased dramatically.

Female↗
PubMed1989

Serum secretory IgA levels in patients with Behçet disease.

Serum IgA, IgC, IgM and secretory IgA levels in patients with Behçet disease were examined. Among them, serum IgA and secretory IgA levels, which increase in mucosal inflammation, were significantly higher than controls (p less than 0.001, p greater than 0.01). These results indicate that mucosal inflammation, oral and gastrointestinal inflammation, may lead to gram-negative bacterial infection and endotoxin-induced uveitis in patients with Behçet disease.

Adult↗