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Biomedical subjects

S Namura

Publications and source records attributed to S Namura.

At least 73 records · Page 4Linked to original sources
PubMed1992

Aneurysm of the fenestrated basilar artery: report of two cases.

This report describes two patients with fenestrated basilar artery aneurysms, and one of the patients underwent a postmortem examination. In our cases, the aneurysms arose at the proximal end of the fenestration, which involved the proximal third of the basilar artery. Subtraction angiography and oblique projections were essential in diagnosing the aneurysms. Complete neck clipping was successfully performed through a lateral suboccipital approach in the two cases. Technical aspects of neck clipping of the aneurysm of this unique location are discussed. Pathogenesis of these rare aneurysms is also discussed with clinical and histopathological data.

Adult↗
PubMed1992

A three-dimensional measuring system for the human face using three-directional photography.

This study was intended to develop a three-dimensional measuring system of the human face for clinical use, to ensure a high precision and a simple input operation by means of a personal computer and to measure the degree of its accuracy. With this system, it is possible to measure automatically two-dimensional coordinates of hundreds of grid points on photographs of the human face with an image scanner as a reading device and to calculate their three-dimensional coordinates with a computer. An orthognathic surgical case illustrates this technique in which the patient's face is displayed before and after the surgery on a cathode-ray tube (CRT), with the three-dimensional coordinates obtained with this system. A cubic plaster cast with a certain degree of irregularity has been constructed to measure the precision of this system. Comparison was then made between the three-dimensional coordinates obtained with this system and the coordinates obtained with the contact three-dimensional measuring system. The mean of errors and the standard deviation were 0.04 +/- 0.24 mm for the X coordinate, 0.03 +/- 0.16 mm for the Y coordinate, and 0.08 +/- 0.23 mm for the Z coordinate. Thus the accuracy of this system is high enough for the measurement of the human face.

Cephalometry↗
PubMed1992

[Clinical experience with recently produced devices for use in spinal surgery].

The authors reported their clinical experience with devices, which have been recently introduced for spinal surgery. The main roles of such devices are to correct malalignment of the spine and stabilize the spinal instability. Although Harrington's device has been widely used since 1962, its use is gradually decreasing due to its having several weak points, such as its low resistance to distorting forces and its imperfect ability to correct malalignment of the spine. In the present manuscript, the authors describe clinical experience with three kinds of spinal devices. They are Steffee's transpedicular screw for 5 cases of lumbar spondylolisthesis, Roosen-Trauschel compression clamp for 2 cases of atlanto-axial dislocation and Kaneda's device for one case of metastatic T-11 tumor. Good fixation was obtained in 4 cases using Steffee's devices. The injury of the nerve root is one of the most serious disadvantages in this device. Although Roosen-Trauschel compression clamp needs improvement in some aspect, it was able to bring about good stabilization without using sublaminar wiring, which may be a dangerous procedure in the cervical region. Kaneda's device seemed to be useful for the thoracolumbar lesion. Although it needs a relatively radical approach, such as thoracotomy, Kaneda's device brought about good stabilization and corrected the kyphosis. The devices, which are described in the present manuscript, will probably play important roles in spinal surgery in the future.

Adult↗
PubMed1992

[A case report of cervical disc hernia presenting fecal incontinence evoked by walking; spinal intermittent rectal dysfunction].

Intermittent clinical manifestations, the representative one of which is claudication, can be classified into two types; neurogenic and vasculogenic. Although cauda equina lesions are well known as a neurogenic cause, spinal disorders, especially cervical or thoracic cord lesions, have been paid more attention to by several authors recently. We encountered a 42-year-old man with cervical soft disc hernia and ossification of longitudinal ligament, who showed intermittent rectal dysfunction evoked by walking. This peculiar clinical manifestation successfully disappeared after surgical decompression of the spinal cord. Such an interesting case has not been reported in the world literature. The patient was admitted because of numbness in both hands. Neurological examinations on admission showed neither motor weakness nor abnormally increased tendon reflex. Hypesthesia and hypalgesia were noticed below the Th4 dermatome on both sides. Adding to those symptoms, he complained of fecal incontinence evoked by walking 100 meters. This rectal dysfunction became gradually worse. At last he showed fecal incontinence after walking only 10 meters. This was ten days after his admission. Myelogram and computed tomographic scan revealed a cervical soft disc hernia at the C5/6 level and findings of OPLL at the C5 and C6 level. Anterior cervical approach for OPLL and soft disc was used for bone graft insertion from the C4 to the C7 vertebral body. The rectal dysfunction completely disappeared after the operation. The possible mechanisms of intermittent rectal dysfunction evoked by walking were discussed.

Adult↗
PubMed1992

[Intraparenchymal granulocytic sarcoma in acute monocytic leukemia; case report].

Granulocytic sarcoma of the parenchyma of the brain present in a patient with acute monocytic leukemia, and its unusual course during treatment, is described. Four years after diagnosis of acute monocytic leukemia, a 24-year-old man developed severe headache during its remission period. The CT scan showed large intraparencymal mass in the right frontal lobe, which was partially removed and diagnosed as granulocytic sarcoma. Following the operation, radiation in total dose of 35.5 Gy was given to the whole brain, and there was also left intraventricular administration of methotrexate (MTX) and cytosine arabinoside (ara-C). The treatment resulted in the complete disappearance of the intraparenchymal mass apart from small calcifications. Five months later, the patient redeveloped severe headache with consciousness disturbance. CT scan revealed marked swelling in the left cerebral hemisphere with irregular contrast-enhanced areas. The patient died of brain herniation in spite of conservative therapy. Photomicroscopic findings of the left cerebral hemisphere proved the presence of "disseminated leukoencephalopathy" and the absence of tumor cells. On the other hand, the right frontal lesion consisted of no tumor cells but scar tissues. This unusual feature of the CT scan in the terminal stage might be caused by combination with the effect of highly concentrated MTX in the left cerebral hemisphere because of the increased permeability of the ependym and the relatively high radiosensitivity in the non-affected left cerebral hemisphere.

Adult↗
PubMed1990

[A study of dynamics of orthodontic archwire on the dental arch. 1. Distribution of orthodontic forces during labial movement of bilateral incisors].

The study on labial movement of maxillary unilateral incisor had been reported previously. This study was the case of maxillary bilateral incisors. Orthodontic forces during labial movement of maxillary bilateral incisors which were produced by stainless steel archwire with vertical loops and nickel titanium archwire, were measured and were examined the distribution of orthodontic forces to the dental arch in the experimental apparatus with strain gauges. The following results were found: 1. In nickel titanium archwire, orthodontic forces were distributed to the entire dental arch, and the distribution of orthodontic forces could be classified into three types, which were similar to the previous study. 2. In stainless steel archwire with vertical loops, orthodontic forces were distributed only to bilateral incisors and adjacent tooth to bilateral incisors. 3. When bilateral incisors displaced lingually, it showed that there were additional orthodontic forces distributions as if two unilateral distributions were overlapped. 4. For maxillary bilateral incisors were moved in optimum force, some consideration to adjust the loops of stainless steel archwire was needed.

Dental Stress Analysis↗
PubMed1989

[A morphological study of the cranial base and dentofacial structure of Japanese with Angle Class II, div. 1 malocclusion--as compared with American white with Angle Class II, div. 1 malocclusion].

The purpose of this study was to clarify the morphological differences of Angle class II, div. 1 malocclusion between Japanese and American Caucasians by comparing their cranial base and dentofacial morphology. Materials were lateral cephalograms of 61 Japanese (30 males: mean age 12y3m and 31 females: mean age 12y10m) and 67 American Caucasians (27 males: mean age 13y6m and 40 females: mean age 13y) with Angle class II, div. 1 permanent dentition. Results were as follows: 1. The anterior cranial base length in Japanese with Angle class II, div. 1 malocclusion was significantly shorter than that of American Caucasians. 2. The maxillary length in Japanese with Angle class II, div. 1 malocclusion was significantly shorter than that of American Caucasians. 3. Less than SNA, less than SNB and less than ANB showed no significant difference between Japanese and American Caucasians with Angle class II, div. 1 malocclusion. 4. The whole mandibular length in Angle class II, div. 1 malocclusion of Japanese males and American males showed no significant difference. But the mandibular body length of Angle class II, div. 1 malocclusion in Japanese females was significantly shorter than that of American ones. 5. No significant difference was observed in gonial angle when the two groups were studied. 6. As compared with American Caucasians, the backward rotation of the mandible was evidently observed in Japanese with Angle class II, div. 1 malocclusion.

Adolescent↗
PubMed1989

[Application of the finite element method to craniofacial growth analysis. 4. Three-dimensional application of tensor analysis].

The purpose of this study is the 3-dimensional application of finite element method to analyze the craniofacial growth. In our previous studies, 2-dimensional finite element method was applied to analyze and to predict the craniofacial growth. In case of 2-dimensional application, the normal and shear strains were given by the displacements u, v that were linear functions of coordinates x, y. In the 3-dimensional case, six strain components are required to obtain the extension ratio and the directions of three-principal axes. In this study, for the 3-dimensional application, four-noded, pyramidal elements were used and twelve 3-dimensional elements were constructed. Materials were longitudinal frontal and lateral cephalometric X-rays of 4 males and 4 females from 7 to 10 years with normal occlusions. 3-dimensional coordinates of each nodal points were calculated by transforming 2-dimensional coordinates on the frontal and lateral cephalometric X-ray films. Coordinates of the nodal points at 7 years were standards against that results of the finite element method from 8 to 10 years were obtained. They were subjects of the analysis that elements equivalent to the cranial base, the maxillary portion, the maxillary alveolar portion and the posterior pharyngeal portion. Summarized results were as follows. 1. It was observed that the similar figured extension of the anterior cranial base element. 2. The posterior cranial base element extended to right, anterior and upwards direction. 3. On the maxillaly elements, especially, lateral extensions appeared. 4. The element of the posterior pharyngeal portion extended to left and downwards direction. 5. The elements of the maxillary alveolar portion extended to downwards directions. From the above, the directions of transformation of the elements that are selected with voluntary nodal points can be observed. Therefore, 3-dimensional tensor analysis is a method of great significance for obtaining new findings of the craniofacial growth.

Cephalometry↗
PubMed1988

[Reaction of various experimental animals to exposure to acetylcholine or histamine, and morphological observations of bronchial smooth muscle].

We investigated the sensitivity of the airway of various experimental animals to acetylcholine (ACh) and histamine (Hist). The experimental animals were exposed to 0.1% ACh or 0.05% Hist. Guinea pigs and rabbits exhibited an asthmatic reaction to both chemicals, but rabbits seemed to have a milder reaction than guinea pigs to both chemicals. Mice, rats and hamsters showed no reaction. We then performed a morphological study of the airways of 5 species in order to clarify the reason for their different reactivities to ACh and Hist. In the morphological study, abundant smooth muscle could be seen in the terminal bronchioles and respiratory bronchioles of guinea pigs and rabbits. In contrast, animals of other species had little smooth muscle in either site. Mice had no respiratory bronchioles. Consequently, we concluded that there is a high correlation between sensitivity to ACh and Hist and the extent of smooth muscle distribution around the airway.

Acetylcholine↗