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M Naitoh

Publications and source records attributed to M Naitoh.

70 records · Page 4Linked to original sources
PubMed1990

[Quantitative analysis of the complete image layer in rotational panoramic radiography].

Radiography is a fundamental method of examination in clinical dentistry. Rotational panoramic radiography provides comprehensive information on the maxilla and mandible, and is thus a very valuable procedure for dental practitioners. It is impossible for the image layer to be altered to perfectly suit each individual patient, so the closest corresponding image layer is selected from the several layers in the current panoramic x-ray units. Therefore, it is essential for the two-dimensional characteristics of the layers to be accurately understood when performing radiography and diagnosis. There are a number of subjective and objective methods available to evaluate the image layers, but they all have certain disadvantages. Accordingly, an experimental model was used to quantitatively analyze the complete image layer from the anterior to the TMJ region. At first the central plane of the image layer was obtained by analyzing the x-ray beam. Subsequently, the modulation transfer function (MTF) values of the complete image layer from the anterior to the TMJ region were measured using the slit method with digital Fourier transformation. In order to define the image layer, the information transfer factor (ITF) was calculated by integrating the squared MTF from 0 to 10 cycles/mm at each position. The measured image layer was then compared with the layer calculated by the method of McDavid et al. A Veraview apparatus (J. Morita Corp., Japan) with a 1.1 mm primary slit width was used as the panoramic x-ray unit, and DuPont HiPlus/Kodax X-Omat RP was used as the screen/film combination. The results are summarized below. 1. The central plane of the layer, which was obtained by analyzing the x-ray beam, showed a palabolic curve on the right side and a sigmoid curve on the left side, and the forms of the curves differed between the premolar and the molar regions. 2. The average horizontal angle of the beam to the median line on the right and left sides was analyzed using panoramic radiograms. It was 24.2 degrees for the mandibular canine, 58.4 degrees for the surface between the 1st and 2nd molars, and 95.1 degrees for the condyle. 3. When the limit of the image layer was defined as an ITF of 75, the measured image layer thickness was 5.74 mm in the anterior region, 7.4 mm in the canine region, 15.1 mm in the molar region, and 20.7 mm in the TMJ region. The calculated values were 6.16 mm, 8.9 mm, 15.7 mm, and 20.0 mm, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Fourier Analysis↗
PubMed1989

Analysis of endotoxin fever in rabbits by using a monoclonal antibody to tumor necrosis factor (cachectin).

A murine monoclonal antibody to rabbit tumor necrosis factor (TNF; cachectin) was injected intravenously into an endotoxin-treated rabbit to examine the role of endogenous TNF in fever. Both early and late peaks of biphasic fever evoked by the endotoxin injection were suppressed by the antibody. TNF activity was detected in an endotoxin dose-dependent manner in the blood 1 h after the endotoxin injection, which was coincident with the early-peak fever. Although the late-peak fever responded to the antibody, no significant TNF activity was detected in the blood obtained 1 h before the peak response. The blood was found to contain endogenous pyrogen activity, which was stable after heating at 70 degrees C for 30 min and resistant to in vitro treatment with the antibody. Rabbit TNF injection also elicited biphasic fever in rabbits, the second phase of which was found to be mediated by the similar endogenous pyrogen. These results suggest that endogenous TNF plays an important role in eliciting a febrile response to endotoxin.

Animals↗
PubMed1988

[Antiarrhythmic agent caused marked hypoglycemia in a patient receiving hemodialysis: relation with disopyramide and verapamil].

A 70-year-old man with a 5-year history of hemodialysis was admitted to Keio University Hospital due to severe constipation on March 27, 1986. He recognized constipation and abdominal distention one month before admission, and his general condition became gradually worse. After the admission, a barium enema revealed obstruction at the upper portion of the ascending colon. A righ colectomy was successfully performed on April 8. Before the operation he showed frequent premature ventricular beats on his ECGs, but after the operation atrial fibrillation with rapid ventricular responses appeared. The arrhythmia was normalized with the intravenous administration of verapamil and disopyramide and oral administration of those drugs was continued. A few weeks later he was found to be drowsy occasionally. His fasting plasma glucose was revealed to be 29 mg/dl. After the discontinuation of the antiarrhythmic agents his plasma glucose level returned to normal. To see what role disopyramide might play in this hypoglycemic phenomenon, oral glucose tolerance tests were done before and during the administration of disopyramide. The examination revealed stimulation of insulin secretion by disopyramide.

Aged↗
PubMed1987

Restoration of normal febrile response to endotoxin in pyrogen-tolerant rabbits by injection with human beta interferon.

Early-phase pyrogen tolerance was induced in rabbits by two consecutive daily injections of 125 ng of endotoxin per kg of body weight. The second injection of the same dose of endotoxin evoked only a monophasic fever with a peak response 1.5 h after the injection; no second peak was observed. The rabbits were released from the tolerance to develop a typical biphasic fever by an injection of 125 ng of endotoxin along with human beta interferon (HuIFN-beta), although the tolerance-inducing amount of endotoxin alone could not. The profile of the febrile response of tolerant rabbits injected with both endotoxin and HuIFN-beta could not be distinguished from that of normal rabbits. There was no essential difference between natural and recombinant HuIFN-beta in breaking tolerance. Heat-stable (70 degrees C, 30 min) endogenous pyrogen or tumor necrosis factor was increased significantly in concentration in the serum of tolerance-broken rabbits. These results suggest that HuIFN-beta stimulates the production of tumor necrosis factor in tolerant rabbits to elicit the second peak of febrile response.

Animals↗
PubMed1985

Studies on antigenicity of the polyethylene glycol (PEG)-modified uricase.

The purified uricase (urate: oxygen oxidoreductase, EC 1.7.3.3) from Candida utilis was modified to varying degrees with monomethoxypolyethylene glycol (PEG) of different molecular weights using cyanuric chloride as the coupling reagent. The PEG-uricase conjugates were examined on their immunological properties by means of ring test and passive cutaneous anaphylaxis (PCA). As increasing amounts of PEG were attached to uricase, it showed decreasing ability to elicit antibody production in rabbits. When sufficient polymers were attached, the modified uricase was devoid of the capacity to combine in vivo and in vitro with antibodies from guinea pigs injected with the unmodified uricase, however, were still able to react with antibodies to PEG-uricase conjugate. Antibodies against PEG-uricase conjugates also reacted with PEG modified superoxide dismutase (superoxide: superoxide oxidoreductase, EC 1.15.1.1). These results indicate that the coupling of PEG to uricase resulted in the loss of original antigenicity and immunogenicity, but in the appearance of new antigenicity and immunogenicity which never showed any cross-reactions against the native uricase.

Animals↗
PubMed1982

Spontaneous occurrence of atypical hyperplasia and adenocarcinoma of the uterus in androgen-sterilized SD rats.

In SD female rats sterilized by a single injection of testosterone propionate at 2 days after birth, the spontaneous occurrence of atypical hyperplasia and adenocarcinoma of the uterus was observed for a fairly long period (greater than 2 yr). Two atypical hyperplasias and 2 adenocarcinomas were detected in 25 androgen-sterilized rats (ASR) after 500 days of age; in contrast, in 111 normal control rats no abnormal uterine proliferation was detected during a 750-day observation period. These results indicate that a persistence of both hormone imbalances and dysfunctional uteri in ASR induces abnormal uterine proliferation at a late age.

Adenocarcinoma↗
PubMedDate not supplied

AutoCyte SCREEN interactive automated primary cytology screening system. A preliminary evaluation.

OBJECTIVE: To perform a preliminary evaluation of the relative sensitivity of a new interactive automated cytology screening system (AutoCyte SCREEN, AutoCyte, Inc., Elon College, North Carolina, U.S.A.) designed as a primary screening system for AutoCyte PREP monolayer slides (AutoCyte). STUDY DESIGN: Monolayer slides were prepared and evaluated in a masked review both manually and using the automated system. Human and machine performance was monitored and measured. RESULTS: Five hundred eighty-three monolayer preparations, including 56 clearly abnormal cases, were evaluated. The dual and combined computer and cytologist image evaluation resulted in a relatively low false positive rate, 20.8%, and 1.8% false negative rate. Use of the system was efficient, significantly reducing cytotechnologist screening time. CONCLUSION: The integrated AutoCyte cell preparation and automated screening approach seems to hold significant promise for primary cytology screening applications.

Adenocarcinoma↗
PubMedDate not supplied

Chronic vasopressin antagonism in two-kidney, one-clip renovascular hypertension.

The role of vasopressin (AVP) in the maintenance of hypertension in the rat model of two-kidney, one-clip (2K1C) Goldblatt hypertension was assessed using the nonpeptide orally effective V1a receptor antagonist, OPC-21268. Rats were studied eight weeks after surgery when mean arterial pressure (MAP) was significantly increased in 2K1C rats compared to SHAM operated controls (2K1C 139 +/- 6, SHAM 106 +/- 3, P < 0.01). Neither acute (OPC-21268, 30 mg/kg) nor chronic (OPC-21268, 30 mg/kg twice daily) V1a receptor blockade reduced blood pressure in either 2K1C or SHAM rats. The results of binding kinetic studies confirmed that OPC-21268 was effective at its putative site of action, the V1a receptor in both 2K1C and SHAM rats. These results indicate AVP is not involved in the maintenance of blood pressure in the 2K1C model of renovascular hypertension.

Animals↗