Biomedical subjects

Y Hiranuma

Publications and source records attributed to Y Hiranuma.

At least 19 recordsLinked to original sources

PubMed1991

[Mitral regurgitation due to redundant chordae].

This paper reports the etiology and the findings of phonocardiograms and echocardiograms in four cases with mitral regurgitation caused by the redundant chordae. Redundancy of the chordae were determined by the surgeon during operation. The results were as follows: 1. The etiology of redundant chordae was either congenital, rheumatic, or mucoid degeneration. 2. Phonocardiographic findings of this condition are a holosystolic murmur accompanied by a diastolic rumble at the apex. 3. Two-dimensional echocardiogram shows holosystolic bulging of the mitral leaflet to which redundant chordae are attached. 4. The findings of the M-mode echocardiogram are multiple linear echoes and bowing of the mitral valve in systole.

Adult↗

PubMed1990

[Mitral valve function after open mitral commissurotomy: assessment by Doppler echocardiography].

To evaluate mitral valve function and its long-term outcome after open mitral commissurotomy (OMC), we examined 39 patients using Doppler echocardiography. There were 13 males and 26 females; who were examined a total of 83 times after the surgery at about one year intervals (seven to 240 months, averaging 78 months). We measured the velocity of transmitral blood flow using the continuous wave Doppler method (CWD), and the transmitral pressure half time (PHT), mean velocity (m V) and peak velocity (pV) were calculated. The presence and severity of mitral regurgitation (MR) were assessed by color flow mapping. 1. PHT gradually increased and significantly correlated (r = 0.63, p less than 0.001) with the months passed after OMC. The regression line of PHT in postoperative months was "PHT = 0.70 x PMo + 83" (PMo = postoperative months). The mV and pV tended to increase gradually, but did not significantly correlate with the months passed after the surgery. 2. Among the 39 patients, 28 (72%) had MR, and their severity was classified as 1+ in two, 2+ in 19, 3+ in six and 4+ in one. Among 21 patients who had no MR before OMC, MR appeared in 12 (57%), and its severity was classified as 1+ in one, 2+ in nine and 3+ in two. All five patients with preoperative MR had MR postoperatively, and their severity was classified as 1+ in one, 2+ in two and 3+ in two. The presence of the preoperative MR of the remaining 13 patients was unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

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↗

PubMed1990

[A case of mitral valve prolapse associated with unusual posterior wall motion of the left ventricle: where has the myocardial theory gone?].

A case with mitral valve prolapse was reported in which unusual movement of the posterior left ventricular wall was observed. The patient was a 45-year-old woman. Physical examination revealed loud multiple clicks at the apex. An electrocardiogram revealed T wave inversion in leads 2, 3 and aVF. Two-dimensional and M-mode echocardiography disclosed mid-systolic buckling of the mitral valve and late systolic 'dip' in the posterior wall of the left ventricle. An exaggerated excursion of the posterior wall during early diastole was also recorded by M-mode echocardiography. Pulsed and M-mode color Doppler echocardiography detected unusual anterograde flow near the mitral valve. This flow coincided well in timing with the early diastolic exaggerated excursion of the posterior wall. A discussion was made on the relation between abnormal left ventricular wall motion and mitral valve prolapse.

Echocardiography, Doppler↗

PubMed1989

[Biomechanical study on the mechanism of the mandibular condylar fracture. 1].

The condylar process is one of the sites predisposed to fracture clinical and experimental studies on the fracture mechanism have so far been undertaken by a number of our predecessor. However, the difference in the fracture mechanisms of intracapsular and extracapsular fracture has not completely been determined yet. In a Japanese Journal of Oral and Maxillofacial Surgery: Vol.32, 1362-1381, 1986: Shimada have previously reported the strong possibility that the direction and extend of fracture lines in the fracture of condylar process were influenced by the morphological characteristics of the condylar head. In order to verify this postulation, stress distribution patterns by the cross-sectional morphology of various types of condylar heads were investigated by two-dimensional finite element method, using 15 Indian edentulous mandibles. In this analysis, loading was applied to three directions in the model of the mandibular body, and two directions in the model of the mandibular head. The results indicated the following something. 1) With the loading in the direction of condylar head from mandibular angle, compressed stress arose on the condylar head with the surface. And with the loading in the direction of condylar head from chin and mandibular body, tugged stress arose on the condylar neck. 2) With the loading in the direction of vertical, these were conjectured that comminuted fracture arose on convex type, sagittal fracture arose on concave type and a style midway fracture arose on straight type. 3) With the loading in the direction of lateral, these were conjectured that fracture of condylar neck arose on the three types, especially the tendency was remarkable on straight type.

Biomechanical Phenomena↗

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

[Is this mitral valve prolapse? A case of mitral regurgitation with early systolic murmur due to early systolic prolapse of the posterior leaflet].

This paper reports the findings of phonocardiograms, echocardiogram and Doppler echocardiograms in a case of a 50-year-old man with early mitral valve prolapse with an early systolic murmur. A characteristic early systolic crescendo murmur was recorded at the apex. By amyl nitrite inhalation, the early systolic murmur was attenuated and a late systolic murmur was evoked. On the contrary, methoxamine injection increased the intensity of the early systolic murmur. Early systolic prolapse and early systolic buckling were recorded by two-dimensional and M-mode echocardiography. The phase of mitral regurgitation detected by M-mode color Dopper echocardiography coincided well in timing with the early systolic murmur and the early systolic buckling recorded on the M-mode echocardiogram. A discussion was made on the mechanism of the early systolic mitral regurgitation due to early mitral valve prolapse.

Amyl Nitrite↗

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

Strain distribution during separation of the pterygomaxillary suture by osteotomes. Comparison between Obwegeser's osteotome and swan's neck osteotome.

In the Le Fort I type osteotomy, separation of the pterygomaxillary suture is a dangerous manoeuvre which must be carried out during the surgical procedure. To determine the osteotome best suited for safe separation of the pterygomaxillary suture, we measured the strain distribution over the surrounding bone structures during the osteotomy, employing two types of osteotomes. In both the Obwegeser osteotome group and swan's neck osteotome group, a large strain was measured at the medial pterygoid plate on the side of osteotome application. The intensity of the strain at the medial pterygoid plate was higher in the Obwegeser osteotome group than in the swan's neck group. With the Obwegeser osteotome which is routinely and commonly used in orthognathic surgery, safe separation of the suture cannot be accomplished unless the blade is correctly applied to the suture and superoposterior compression of the pterygoid process is avoided.

Adult↗

PubMed1988