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Biomedical subjects

T Hamanaka

Publications and source records attributed to T Hamanaka.

At least 37 records · Page 2Linked to original sources
PubMed1997

One-stage reconstruction of established facial paralysis using a rectus abdominis muscle transfer.

A free vascularized rectus abdominis muscle graft with a long motor nerve was used for reconstruction of unilateral established facial paralysis in one stage. Regarding the procedure, the pedicle vessels were anastomosed to the recipient vessels in the ipsilateral face, and the motor nerve of the muscle was sutured to the contralateral facial nerve. The advantages of using the rectus abdominis muscle are as follows: (1) the muscle is very thin, not bulky, (2) the muscle can be split easily to reduce the volume, (3) the intercostal nerve is long enough (more than 20 cm) to reach the contralateral facial nerve for suturing, (4) the pedicle vessels are large and long, (5) it is possible to carry out simultaneous operations with two teams, and (6) the donor-site morbidity is minimal. The disadvantages of this method are that complicated surgical dissection is required to obtain a motor nerve and that a postoperative abdominal hernia may occur.

Adolescent↗
PubMed1997

Typus melancholicus is not the premorbid personality trait of unipolar (endogenous) depression.

The present paper aims to examine whether Typus melancholicus is a distinguishing premorbid personality of unipolar (endogenous) depressive patients vis-à-vis psychiatric patients with different diagnoses and healthy control subjects. Two observer-rated scales for Typus melancholicus were administered to a consecutive series of psychiatric patients (n = 140) and a group of control subjects (n = 84). To the authors' own surprise, the only statistically significant finding was the low Typus melancholicus score among unipolar (endogenous) depressives in comparison with normal controls but not with other psychiatric patients. In addition, this finding held only for one of the two rating scales and among women only. According to the other rating scale for Typus melancholicus, there was no difference between unipolar (endogenous) depressives and the normal control or other psychiatric patients. These findings are discussed with particular emphasis on the methodological aspects of studies of premorbid personality of psychiatric disorders, a favored subject in the psychiatric science for decades.

Adolescent↗
PubMed1997

Pure amnesia caused by bilateral temporal lobe astrocytoma--case report.

A 32-year-old male presented with progressive pure amnesia caused by astrocytoma invading the bilateral medial temporal lobes. Methionine positron emission tomography demonstrated the extent of tumor invasion well. His memory impairment was partially improved by treatment for the astrocytoma. Lesion of the bilateral hippocampus causes memory impairment, but pure memory loss without other associated neurological sign or deterioration of consciousness is rare in a case of cerebral neoplasm.

Adult↗
PubMed1996

Ocular signs and symptoms caused by exposure to sarin gas.

PURPOSE: Ocular signs and symptoms that occurred in people exposed to sarin gas in a subway sarin gas attack were studied. METHODS: Among victims of sarin gas exposure, 96 were treated by us. RESULTS: Ocular signs and symptoms caused by sarin gas exposure included miosis, conjunctival injection, and ocular pain. CONCLUSIONS: Ocular signs and symptoms spontaneously resolved between three and 21 days after exposure in most cases. Treatment with 0.5% tropicamide ophthalmic solution was effective in decreasing ocular pain.

Conjunctival Diseases↗
PubMed1996

X-ray diffraction pattern from internal structure of bovine rhodopsin.

Pure bovine rhodopsin pellets were prepared by removal of cholic acid from rhodopsin-cholic acid complex, and X-ray diffraction patterns from the internal structure of rhodopsin were obtained for the first time using wet and dry pellet samples. The peaks at around 10 and 4.3 A spacings observed for both samples can be attributed to alpha-helices in rhodopsin molecule, providing direct evidence of the helical structure of rhodopsin. A shoulder peak at around 34 A spacing was also observed for the dry pellet, which can be explained by the first-neighbor distance between rhodopsin molecules in the sample.

Animals↗
PubMed1996

[Visual illusion with 90-degree forward rotation on the sagittal plane due to acute paramedian pontine infarction].

We report an unusual and dramatic type of visual illusion, a 90-degree forward rotation of vision on the sagittal plain in 2 cases of acute paramedian pontine infarction. At initial neurological examination, they were both alert and well-oriented. The one case had slight right lateral gaze palsy, left motor paresis and hallucinose pédunculaire, and the other case had slight right gaze palsy, right Horner's syndrome, slight left sensory deficit and left limb ataxia. They complained that they felt as if they themselves, the bed, the floor and the ceiling were standing vertically, although actually they were lying on the bed horizontally. The sensation of the 90-degree rotation of vision frequently occurred as soon as they awoke or opened their eyes, and continued for a few minutes. The illusion disappeared within several days after the onset of the pontiue infarction. These visual symptoms may be contributed to imbalance of the integrated processing among the vestibular, visual and somatosensory systems resulting from the brainstem lesion involving the vestibulo-cortical network fibers, or may be considered as dysfunction of the ascending reticular activating system similar to the mechanism of hallucinose pédunculaire.

Aged↗
PubMed1996

[Application of oculokinetic perimetry in examination of the eye].

Oculokinetic perimetry was performed using the same protocol at four health screening facilities to determine its usefulness for identifying visual field abnormalities including glaucoma during complete physical screenings in Japan. Ophthalmoscopy of the optic disc, 26-point oculokinetic perimetry (OKP), and applanation tonometry were performed in 2,768 eyes. If any one of the tests yielded an abnormal result, the eye was then examined with a Humphrey visual field analyzer (HVFA, program 30-2). After the tests were completed, the results were evaluated by ophthalmologists for evidence of primary open-angle glaucoma and normal tension glaucoma and were classified into one of 3 groups: confirmed glaucoma, suspected glaucoma, and no glaucoma. OKP detected abnormalities in the visual field in 96 eyes (3.5%). Of these 96 eyes, 29 eyes had confirmed glaucoma, 52 eyes were suspected of having glaucoma and 15 eyes had no glaucoma. The remaining 15 eyes had no glaucoma, but in 7 of them other ophthalmological disease was diagnosed. The sensitivity, specificity, positive predictive value, and negative predictive value of OKP for detecting glaucomatous visual field defect were 0.46, 0.99, 0.84 and 0.96, respectively. The high specificity and negative predictive value show that OKP is unlikely to produce false positive results, but its low sensitivity suggests that it is not suitable for the early detection of glaucoma. However, OKP identified advanced glaucoma and other ophthalmological diseases associated with visual field abnormalities, suggesting that it is a useful screening test.

Adult↗
PubMed1996

[A study of utilization and imitation behavior in cases with striatocapsular infarction].

Utilization behavior (UB) and imitation behavior (IB) were first described by Lhermitte (1983; 1986) for neurobehavioral disorders due to the frontal lobe damage. Recently, the similar symptoms were also observed in several reports of subcortical lesion cases without any lesion of the frontal lobe. We studied 16 consecutive patients with unilateral striatocapsular infarction (SCI), and found 7 patients (44%) presenting UB and/or IB. Characteristics of patients with UB and/or IB revealed the following factors: older age, higher frequency of right-sided lesion, absence of severe aphasia or apraxia, higher frequency of unilateral spatial neglect and/ or psychic change, and no evidence of significant large cerebral artery lesion on angiography. In most of SCI cases, whether IB and/or UB was present or not, the single-photon emission CT demonstrated decreased perfusion in the ipsilateral frontotemporal areas, and the result of neuropsychological assessment was compatible with frontal lobe dysfunction. UB and IB observed in our patients are not only considered to have resulted from secondary impairment of frontal lobe, but also regarded as one of the right hemispheric syndromes associated with such background factors as aging, neglect and general inattention.

Adult↗
PubMed1995

Connected deep femoral and gluteal perforator-based flap for repair of an extensive defect on the posterior thigh.

An island connected "Siamese" deep femoral and gluteal perforator-based flap with double vascular pedicles, the perforators from the deep femoral and superior gluteal arteries, was transferred successfully to repair an extensively large posterior thigh defect in an 84-year-old man. For reconstruction of large, massive defects of the posterior thigh region, this connected "Siamese" flap has the following advantages: (1) the flap and the pedicles are nearest to the defect, (2) the skin territory of the flap is extremely long, (3) the flap elevation is easy, because there are several perforators that can be considered as pedicle candidates in both the deep femoral and the gluteal perforator-based flaps, (4) there is no necessity for positional change to elevate the flap, and (5) no sacrifice of muscles implies little postoperative functional limitation of the donor leg.

Aged↗
PubMed1994

The specific binding site of the volatile anesthetic diiodomethane to purple membrane by X-ray diffraction.

To determine the binding site of volatile anesthetics on purple membrane, diiodomethane (CH2I2) was used as a label in X-ray diffraction experiments. At less than 3 mM diiodomethane, purple membrane retains its two-dimensional crystallinity of bacteriorhodopsin, absorption spectra show only a little blue shift and the decay time of the M-intermediate becomes fast in flash photolysis experiments. These effects are similar to those of other anesthetics previously studied. The position where the anesthetic binds was identified by difference Fourier methods, and refined by model calculations. This study suggests that volatile anesthetics bind specifically to the protein-lipid interfacial region near the surface of membrane.

Anesthetics↗
PubMed1994

X-ray diffraction study of the live squid retina.

In previous studies of invertebrate rhabdomes by X-ray diffraction, glutaraldehyde fixation of the retina was used because this tissue is very labile and, without fixation, disintegrates within an hour of dissection. However, with conventional X-ray apparatus more than ten hours exposure time was needed to record a diffraction pattern. In this study, X-ray diffraction patterns from unfixed squid retina could be successfully obtained by use of synchrotron radiation and a storage phosphor screen as detector. The diffraction spots were indexed on a two-dimensional hexagonal lattice of 60 nm. X-ray data was analysed by comparing Patterson functions calculated from the diffraction intensities with those based on model building. The hexagonal shape of microvillar cross section was suggested by the systematic weakness of (0, k) reflections beyond k = 4 and the appearance of the six symmetry-related diffuse maxima around (4 nm)-1. The best-fitting model showed a large gap between adjacent microvilli (approximately 12 nm), which has been expected (for ionic current flow through the inter-microvillus space to generate the membrane potential) but not observed with the chemically fixed retina, possibly due to an artifact of fixation. Also, the existence of massive inter-microvillus material, scarcely observed by conventional electron microscopy, has been confirmed.

Animals↗
PubMed1994

Platelet aggregation on the endothelium of Schlemm's canal.

By using monkey eyes and light microscopy, transmission electron microscopy and scanning electron microscopy we have studied the role of platelets in Schlemm's canal. In eyes connected to a reservoir and subjected to an elevated intraocular pressure, there was break-down of the cell membranes facing the invaginations into the endothelial cells, resulting in local protrusions from the invaginations and ruptures. Other unphysiological openings in the inner wall were due to separation of the intercellular junctions. Aggregates of platelets were observed at both these types of openings. Small aggregates were observed also in massaged eyes and in eyes which had not been touched before fixation. It seems likely that the intercellular junctions are fragile, tending to disrupt even under normal conditions and that platelets play a role in their repair. It is also suggested that platelets tend to restrict the size of the physiological pores.

Animals↗
PubMed1994

One hundred years of neuropsychology in Japan: retrospect and prospect.

The development of neuropsychology in Japan since the end of the 19th century will be outlined, including a number of pioneering works that gave a scientific basis to contemporary Japanese neuropsychology. The activities of societies/associations of related disciplines as well as the educational systems of clinical and experimental neuropsychology, which represents in Japan an interdisciplinary field, will be described. After national and international activities are mentioned, a review of significant Japanese contributions to main topics in neuropsychology will be given in some detail: dementia, memory disorders, frontal lobe syndromes, aphasia-alexia-agraphia, callosal syndromes, and specific right hemisphere syndromes. The issues of these interdisciplinary scientific investigations have found application in language and cognitive disabilities of brain-damaged patients, as well as evaluation of medical treatments and comedical rehabilitational effects, care, and counseling. Finally, some comments will be presented on possible and desirable developments of Japanese neuropsychology in the future.

History, 19th Century↗
PubMed1994

Free rectus femoris muscle transfer for one-stage reconstruction of established facial paralysis.

The free vascularized rectus femoris muscle graft with a long motor nerve was used for reconstruction of unilateral established facial paralysis in one stage. The pedicle vessels were anastomosed to the recipient vessels in the ipsilateral face, and the motor nerve of the muscle, which was led through the upper lip, was sutured to the contralateral facial nerve. The advantages of this one-stage reconstruction as compared with surgery involving second-stage reconstruction are that the reconstruction can be completed in one stage and that the period required for muscle refunctioning after surgery is short. The vascular supply of the rectus femoris muscle can emanate mainly from the lateral circumflex femoral artery. In our cadaveric study, five types of variation were found for origination of a nutrient artery of the muscle. The most common type was one in which the artery derived from the descending branch of the lateral circumflex femoral artery (39 percent). The motor nerve of the rectus femoris muscle is derived from the femoral nerve under the inguinal ligament and runs downward through the intermuscular space between the sartorius muscle and the iliopsoas muscle before entering the posteromedial part of the upper third of the rectus muscle. The advantages of using the rectus muscle are as follows: (1) safety and simplicity exist with one main large arterial supply for arterial anastomosis; (2) the length of the femoral nerve (more than 20 cm) is adequate for reaching the contralateral facial nerve for suturing; (3) a simultaneous operation by two teams is possible with the patient in the supine position; (4) the force and distance of contraction are appropriate to reanimate the face; (5) the rectus muscle can be separated as a segment with appropriate lengths, size, and power for replacing lost muscles in the face; (6) the tendinous fascia in both ends provides a reliable point for anchoring sutures, which provides firmer attachment; and (7) no loss of donor leg function occurs.

Adolescent↗
PubMed1994

Unusual findings on PET study of a patient with posterior cortical atrophy.

We present a patient with posterior cortical atrophy in whom positron emission tomography (PET) showed unusual findings. This 65-year-old man had a 5-year history of slowly progressive apperceptive visual agnosia and Balint syndrome, but with a relatively well-preserved intelligence and language ability even in the later stages of illness. No relevant features in this patient or his family were identified. Laboratory and radiographic investigations indicated that cerebral damage was due to primary degeneration. His symptoms resembled those of patients with posterior cortical atrophy. A PET study revealed that cerebral metabolism was reduced in the dorsal regions of the entire cortex and asymmetrical with the main site of damage on the right. The severity in asymmetry increased dorsally. These 2 types of predilection for dorsal regions had not previously been reported in such patients. These unusual PET findings may indicate the presence of pathological changes not yet identified.

Aged↗
PubMed1993

A combined anterolateral thigh flap, anteromedial thigh flap, and vascularized iliac bone graft for a full-thickness defect of the mental region.

A triple combined anterolateral thigh flap, anteromedial thigh flap, and vascularized iliac bone graft was used for reconstruction of a full-thickness defect of the mental region after wide resection of advanced tongue cancer. The distal end of the pedicle vessels of these double skin flaps, i.e., the lateral circumflex femoral system, was directly anastomosed in tandem to the pedicle of the iliac bone graft, which was enveloped by these flaps. The advantages of this iliac osteocutaneous flap are as follows: It can be transferred within a shorter surgical time because the flaps can be obtained in the supine position simultaneously with tumor resectioning; and its skin components can be separated from the bone because each component has its own pedicle vessels, has a longer vascular pedicle (> 10 cm), and has a thicker crest of the bone graft. This flap is believed to be suitable for reconstruction of large full-thickness defects in various sizes of the mandibular and maxillary regions of the face.

Aged↗