Biomedical subjects

M Okitsu

Publications and source records attributed to M Okitsu.

At least 19 recordsLinked to original sources

PubMed1995

Inhibition of the endothelin-converting enzyme by pepsin digests of food proteins.

Inhibitory activities toward the endothelin-converting enzyme (ECE) were detected in pepsin digests of bonito pyrolic appendix and beef. After Sep-Pak C18 fractionation, this activity from bonito and beef was recovered in the 50% and 25% ethanol fractions, respectively. Activities were also recovered in the ultrafiltrate (< 5000 Da), and disappeared after a pronase treatment. Therefore, these inhibitory activities may have peptidic properties.

Animals↗

PubMed1994

D-Val22 containing human big endothelin-1 analog, [D-Val22]Big ET-1[16-38], inhibits the endothelin converting enzyme.

Endothelin converting enzyme (ECE) is essential for generation of the biological effects of endothelin-1 (ET-1) from a precursor, big endothelin-1 (Big ET-1). We synthesized four analogs of human Big ET-1[16-38], substituted with single D-amino acids at P1, P2, P1' and P2' positions. ECE activity was determined using an ET-1 specific radioimmunoassay system. None of the D-amino acid containing Big ET-1 analogs were apparently cleaved by ECE, however, one of the synthetic peptides, [D-Val22]Big ET-1[16-38], strongly inhibited the ECE activity. Furthermore, when this D-Val22 containing peptide was preadministered to rat striatum, it was found to inhibit the dopamine release induced by Big ET-1. This result suggests that the D-Val22 containing peptide inhibits the ECE activity in vivo. The D-Val22 containing inhibitor offers hope of developing more potent and highly specific ECE inhibitors of therapeutic significance.

Amino Acid Sequence↗

PubMed1994

[Anticoagulant effect of a single bolus injection of parnaparin sodium (LHG) on a hemodialysis model in dogs].

Hemodialysis was performed on dogs, following intravenous bolus injections of LHG at dosage levels of 50, 100 and 200 IU/kg and heparin at the levels of 100 and 200 IU/kg. LHG exerted dose-dependent anticoagulant effects and prolonged the hemodialysis time, compared to heparin with similar anti-Xa activity. When LHG was administered, the half-life of plasma anti-Xa activity was longer than that of heparin at similar anti-Xa activity. LHG prolonged the activated partial thromboplastin time (APTT) linearly and dose-dependently. However, the prolongation was much less than that of heparin, and the anticoagulant activity of LHG continued even after the APTT returned to the value before LHG administration. When LHG was administered, whole blood Xa activated coagulation time (XCT) and plasma Xa activated coagulation time (PXCT) were prolonged in a significantly greater degree compared to APTT. Therefore, XCT and PXCT were considered to be appropriate parameters for monitoring LHG. In the groups administered with LHG at 100 and 200 IU/kg, where hemodialysis could be continued for 8 hr, the tissue factor pathway inhibitor (TFPI) activity in the plasma tended to show a sustained increase. These findings suggested the possibility that not only the antithrombin III dependency mechanism but also the TFPI mechanism contributed to a longer LHG hemodialysis duration compared to heparin administration.

Animals↗

PubMed1993

c-fos m-RNA expression after treatment with fetal bovine serum and epidermal growth factor for osteoblastic MC3T3-E1 cells cultured in a low calcium environment.

This paper examines the existence of c-fos mRNA expression in osteoblastic MC3T3-E1 cells cultured in a low calcium environment. The MC3T3-E1 cells were placed in a serum free medium for 24 hours after subconfluence and then the cells were treated with fetal bovine serum and epidermal growth factor for 0, 5, 10, 15, 30, or 60 minutes. The c-fos m-RNA expression was found in the MC3T3-E1 cells cultured in both normal medium (control group) and low Ca medium (low Ca groups). The degree of expression was significantly higher in the low Ca group than in the control group in each treatment period (p < 0.01) and in both groups, after the treatment with FBS or EGF, the expression levels increased with time at 5 and 10 minutes but decreased at 15 minutes. Thereafter, levels increased again to reach to a maximum at 30 minutes after which it decreased rapidly. On the other hand, in both groups, after the treatment with EGF, the expression increased at 30 minute. This suggests that the MC3T3-E1 cells placed in a low calcium environment react to restore cell functioning to normal at the gene level.

Animals↗

PubMed1993

The changes of c-fos mRNA expression in the protein kinase C activated-osteoblastic MC3T3-E1 cells cultured in a low-calcium environment.

The effect of phorbol 12-myristate 13-acetate (TPA) on the c-fos mRNA expression in the osteoblastic MC3T3-E1 cells cultured in a low-calcium environment was examined. The c-fos mRNA expression in MC3T3-E1 cells with the treatment of TPA was enhanced under the low-calcium environment. This fact suggests that TPA induced-protein kinase C enhancement produced the increase of c-fos mRNA expression, and that protein kinase C may be intimately involved in c-fos mRNA expression.

Calcium↗

PubMed1991

Molecular and crystal structures of 2-(2-pyridyl)thioacetamide derivatives and possible relationship with inhibitory activity for gastric acid secretion.

As a possible method to determine the key atoms and their spatial orientation which are necessary for the gastric mucosal protective and antisecretory activity, crystal structures of sixteen 2-(2-pyridyl) thioacetamide derivatives have been analyzed by the X-ray diffraction method. The characteristics of the molecular and crystal structures of the derivatives are described in this paper. The energetic stability of the molecular conformation is also investigated by means of the molecular force field method. Using the conformational data, a possible relationship between the stereostructure and inhibitory activity for gastric acid secretion is considered by QSAR analyses. The results suggest that the activity is related to the overall molecular conformation, and that the spatial distribution of the side-chain polar atoms with respect to the fixed pyridine is especially important for the activity.

Animals↗

PubMed1990

[Influence of change in dental chair position on circulation kinetics. 1. Effects on rate x pressure product].

The rate x pressure product is a product of the systolic blood pressure and heart rate and is widely used in clinical medicine as an index of the cardiac oxygen supply-demand balance. Employing 20 healthy male subjects, we studied the changes in the rate x pressure product due to a body position change from the sitting position to the supine position in a dental chair. The following results were obtained: 1. The change from the sitting position caused a 10% decrease in the rate x pressure product, and this value did not return to the initial sitting position value even after 5 min in the supine position. 2. The heart rate tended to decrease due to the position change. 3. Immediately after the position change, the systolic blood pressure decreased significantly (p less than 0.05), but it tended to return to the initial value with the lapse of time. The lower rate x pressure product in the supine position suggests that the supine position is more advantageous than the sitting one in treatment of the elderly and patients with cardiovascular diseases from the viewpoint of the systemic cardiovascular kinetics.

Blood Pressure↗

PubMed1990

[Epidermoid cyst of the oral floor with massive deposition of melanin in the cystic epithelium].

Dermoid cyst or epidermoid cyst of the oral cavity usually occurs in the floor of the mouth. We encountered a 21-year-old woman who had developed epidermoid cyst in the oral floor. Since infancy she had been aware of a swelling in the oral floor. Recently, the swelling began to grow larger gradually. The lesion was excised under general anesthesia by intraoral approach. The swelling was spherical in shape, measured 50 x 45 x 40 mm in size, and weighed 40 g. Histopathological examination revealed keratinized, stratified squamous epithelium on the cyst wall and marked deposition of melanin at the base of the epithelium.

Adult↗

PubMed1989

Structure of 5-methoxy-2-([4-methoxy-3,5-dimethyl-2-pyridinyl) methyl]sulfinyl)-1H-benzimidazole (omeprazole).

C17H19N3O3S, Mr = 345.42, triclinic, P1, a = 10.686 (5), b = 10.608 (7), c = 9.666 (6) A, alpha = 119.75 (5), beta = 112.02 (5), gamma = 68.33 (4) degrees, V = 859 (1) A3, Z = 2, Dm = 1.332 (2), Dx = 1.335 g cm-3, Cu K alpha, lambda = 1.5418 A, mu = 18.04 cm-1, F(000) = 364, T = 293 K, R = 0.057 for 1962 observed reflections. The methylsulfinyl group, which adopts a trans conformation, links the pyridine and benzimidazole rings in an almost coplanar orientation. Thus the molecule, as a whole, adopts a nearly extended form. Two centrosymmetrically related molecules form a cyclic dimer by intermolecular N-H...O hydrogen bonding, and the dimers are held together by van der Waals contacts between the neighboring aromatic rings in the crystal structure.

Omeprazole↗

PubMed1989

[Measurement of oral and facial blood flow with a laser Doppler flowmeter. 4. Alteration of oral blood flow by position change].

The laser doppler flowmeter was developed by Stern in 1975 and applied for practical use by Nilsson et al. in 1980. Since then, it has been used in various fields of medicine. The primary advantages of this device an that it is noninvasive and can monitor the blood flow continuously and rapidly. We used a Laser doppler flowmeter to continuously monitor the change in the oral peripheral blood flow due to changes in the body position of patients in a dental chair, since such changes are unavoidable during the course of dental treatment. A change from the sitting position to the supine position caused an increase in oral blood flow in 19 of 20 patients. In terms of the mean value per minute, oral blood flow was 23% greater in the supine position.

Blood Flow Velocity↗

PubMed1989

[Five cases referred to the First Department of Oral Surgery due to failure of impacted mandibular third molar extraction].

Of patients referred to our department over the post two years due to failure of tooth extraction 5 with impacated mandibular third molars were treated. We found that extraction had been hindered by the narrow operative field due to inadequate incision of the overlying mucosal tissue, insufficient bone resection and inadequate separation of the crown and root.

Humans↗

PubMed1989

[Two cases of Frey's syndrome].

During the taking of meals, complex symptoms such as perspiration, rubor, and febrile sensation can appear on the skin overlying the temporal area or the parotid gland after the passage of some time after an operation in the parotid area or trauma inflicted to this area. This phenomenon is usually called Frey's syndrome. We recently encountered two cases of this syndrome. The patients were a 16-year-old boy who developed this syndrome following open reduction of the fractured left temporomandibular articular process and a 72-year-old man who developed it following left hemimandibulectomy and left radical neck dissection performed for the treatment of left mandibular gingival cancer. Frey's syndrome is a relatively rare surgery-associated complication. However, it may be advisable to inform the patient of this possibility prior to an operation, because patients may be severely afflicted by heavy perspiration if this syndrome develops over an extensive area.

Adolescent↗

PubMed1989

[A case of bilateral impaction of the lower second molars].

A case of bilateral impaction of the lower second molars is presented. A 15-year-old boy with an ill feeling at the right lower first molar was referred to us. X-ray examination revealed bilateral impaction of the lower second molars and the presence of bilateral teeth that seemed to be the unerupted third molars distal to the impacted second molars. Furthermore, a radiolucency approximately 3 X 3 mm in size was detected in the mesioapical region of the right lower first molar. These impactions were managed under local anesthesia by extraction of the right lower first molar and fenestration of the right lower second molar. After approximately 4.5 months, the right lower third molar was extracted. It was further followed approximately 1 month later by extraction of the left lower third molar and ipsilateral fenestration of the lower second molar. As a result, the right lower second molar erupted but it was considerably inclined in a mesial direction. The left lower second molar erupted normally almost up to the occlusal plane. In the absence of systemic abnormality, facial trauma, and maldevelopment of the jaw, impaction seemed to have been closely associated with some unknown local factor.

Adolescent↗

PubMed1988

Calcifying odontogenic cyst immunohistochemical detection of keratin and involucrin in cyst wall.

Calcifying odontogenic cysts (COC) were immunohistochemically described using different keratin proteins and involucrin as well as histopathology. The cystic lining epithelium was composed of calcifying, keratinizing, squamous, and columnar epithelial cells, and included calcified masses of irregular shape and various size as well as ghost cells. Calcifying epithelium gave negative or only trace staining for keratins detected with low molecular keratin (PKK1), but were regularly positive with high molecular keratin (KL1) and polyclonal antibody for keratin (TK). They were occasionally positive for involucrin. The cells located in the periphery of the calcified masses had a particular abundance of high molecular weight and total keratins (KL1 and TK). Calcified bodies and ghost cells were devoid of any immunoreactivity. Squamous epithelium was relatively similar to that of normal squamous cell epithelium in the oral mucosa. It were most commonly found in columnar cystic epithelial cells which displayed intense staining with all immunoreagents. It is postulated that such epithelial cells may have a strong potentiality to transform into ghost cells or to undergo metaplasia. They may develop altered synthesis of homogenous acellular materials and finally become transformed into calcifying epithelium containing dystrophic calcified masses.

Adolescent↗

PubMed1988