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Biomedical subjects

S Ebara

Publications and source records attributed to S Ebara.

At least 55 records · Page 3Linked to original sources
PubMed1996

Progressive degeneration of articular cartilage and intervertebral discs. An experimental study in transgenic mice bearing a type IX collagen mutation.

Transgenic mice expressing mutant alpha 1(IX) collagen were produced and found to develop progressive joint degeneration with age, as well as accelerated intervertebral disc degeneration. Radiological and histological studies showed that cervical and lumbar disc degeneration was more advanced in the transgenic mice than in control litter-mates. The changes included shrinkage or disappearance of the nucleus pulposus, and fissures in the annulus fibrosus which sometimes lead to herniation of disc material and slight osteophyte formation. These findings suggest that mutations of the type IX collagen may cause certain forms of degenerative disease in the spine as well as in joints.

Animals↗
PubMed1996

Adsorption of saliva-coated and plain streptococcal cells to the surfaces of hydroxyapatite beads.

This study was conducted to observe the differences between the adsorption of Streptococcus sanguis by saliva-coated and non-saliva-coated cells (plain cells) to the surfaces of saliva-coated, bovine serum albumin-coated or buffer-washed hydroxyapatite beads. Saliva treatment of bacterial cells altered the manner of saturation due to changes of affinity and/or the maximal number of adsorption sites on the hydroxyapatite beads. This result indicates that saliva treatment of bacterial cells might be a necessary step in testing bacterial adsorption to saliva-coated hydroxyapatite beads or saliva-coated teeth.

Adsorption↗
PubMed1996

Preclinical Cushing's syndrome: report of four cases and analysis of steroid contents in adenomas.

We report 4 cases of preclinical Cushing's syndrome (PCS) that were discovered incidentally by computed tomography (CT) as adrenal incidentalomas. Routine endocrine examinations revealed a suppressed plasma ACTH level. A final diagnosis was made by means of precise endocrine assessments and adrenal scintigraphy with radiolabelled iodocholesterol. Although endocrine data varied, the positive accumulation of radioisotope in the adrenal tumor, with nonvisualization of the contralateral side, was observed in all cases. Endocrine studies and analyses of steroid contents in tumors by HPLC suggested that subtypes or heterogeneous forms of this disease entity may exist. One type shows small tumors with relatively elevated cortisol production, and a disturbed diurnal rhythm and suppression of plasma cortisol with dexamethasone (DXM). The other type showed large tumors with weak-to-average cortisol production, and the diurnal rhythm of cortisol was preserved.

17-alpha-Hydroxyprogesterone↗
PubMed1996

The cervical spine in athetoid cerebral palsy. A radiological study of 180 patients.

We have reviewed the cervical spine radiographs of 180 patients with athetoid cerebral palsy and compared them with those of 417 control subjects. Disc degeneration occurred earlier and progressed more rapidly in the patients, with advanced disc degeneration in 51%, eight times the frequency in normal subjects. At the C3/4 and C4/5 levels, there was listhetic instability in 17% and 27% of the patients, respectively, again six and eight times more frequently than in the control subjects. Angular instability was seen, particularly at the C3/4, C4/5 and C5/6 levels. We found a significantly higher incidence of narrowing of the cervical canal in the patients, notably at the C4 and C5 levels, where the average was 14.4 mm in the patients and 16.4 mm in normal subjects. The combination of disc degeneration and listhetic instability with a narrow canal predisposes these patients to relatively rapid progression to a devastating neurological deficit.

Adolescent↗
PubMed1995

Vertebral body replacement with a ceramic prosthesis for metastatic spinal tumors.

STUDY DESIGN: This study retrospectively analyzed the clinical outcome of vertebral replacement surgery with our unique ceramic prosthesis for spinal metastases. OBJECTIVES: To indicate the results of vertebral replacement surgery with a ceramic prosthesis. SUMMARY OF BACKGROUND DATA: Spinal metastasis often involves the vertebral bodies, of which abnormal fracture causes intractable pain and paresis. For such conditions, laminectomy or irradiation can have no effect because they do not improve spinal stability. Autogenous bone or bone cement are not durable materials, and fatigue fracture of the implanted material occasionally occurs. We developed a simple prosthesis made of alumina ceramic, a bioinert material, to replace the affected vertebrae. There has not been such a large study to assess vertebral replacement surgery with a ceramic prosthesis. METHODS: From 1972 to 1993, 90 ceramic prostheses were used in 84 patients with spinal metastasis, and the average follow-up period was 26.2 months. The primary tumor was thyroid cancer in 13 patients, breast cancer in 12, multiple myeloma in eight, renal cell cancer in eight, gastrointestinal cancer in eight, and lung cancer in eight. The clinical symptoms were assessed before and after surgery, and the maintenance of operative gain was investigated. RESULTS: Pain relief was achieved in 94%, motor function improved in 81%, and ambulation recovered in 64%. There were no serious complications associated with the procedure, and the operative benefit was maintained until the terminal stage in the vast majority of patients. CONCLUSIONS: In selected patients, vertebral replacement using our prosthesis proved to be a useful procedure, effectively managing the severe spinal pain or neurologic deficits associated with vertebral body destruction.

Adolescent↗
PubMed1995

Structure of the human aggrecan gene: exon-intron organization and association with the protein domains.

The complete exon-intron organization of the human aggrecan gene has been defined, and the exon organization has been compared with the individual domains of the protein core. A yeast artificial chromosome containing the aggrecan gene was selected from the Centre d'Etude du Polymorphisme Humaine yeast artificial chromosome library. A cosmid sulibrary was created from this, and direct sequencing of individual cosmids was used to provide the exon-intron organization. The human aggrecan gene was found to be composed of 19 exons ranging in size from 77 to 4224 bp. Exon 1 is non-coding, whereas exons 2-19 code for a protein core of 2454 amino acids with a calculated mass of 254379 Da. Intron 1 of the gene is at least 13 kb. Overall, the sizes of the 18 introns range from 0.5 to greater than 13 kb. Each intron begins with a GT and ends with an AG, thus obeying the GT/AG rule of splice-junction sequences. The entire coding region is contained in 39.4 kb of the gene. The organization of exons is strongly related to the specific domains of the protein core. The A loop of G1 and the interglobular domain are encoded by exons 3 and 7 respectively. The B and B' loops of G1 are encoded by exons 4-6, and those of G2 are encoded by exons 8-10. These sets of exons, coding for the B and B' loops, are identical in size and organization. This is supported by the intron classes associated with these exons. Exon 11 codes for the 5' half of the keratan sulphate-rich region, and exon 12 codes for the 3' half of the keratan sulphate-rich region as well as the entire chondroitin sulphate-rich region. G3 is encoded by exons 13-18, including the alternatively spliced epidermal growth factor-like and complement regulatory protein-like domains. The correspondence between the exon organization and the protein domains argues strongly for modular assembly of the aggrecan gene.

Aggrecans↗
PubMed1995

Orthopaedic management of spinal metastases.

Spinal metastases result in severe spinal pain, neurologic deficits, or both. These symptoms usually are caused by spinal instability, in which conservative therapy can have no effect, and surgical treatment is required to restabilize the destroyed spinal segments. Surgical indications are instability of the spine, pain and/or paresis resistant to radiation therapy, acute progressing paresis, and unknown histologic diagnosis. There are 2 surgical approaches for vertebral metastases: prosthetic replacement and posterior stabilization. Single or 2 consecutive diseased vertebrae should be treated with replacement surgery. In this series, excellent surgical outcome was attained with this procedure, and surgical benefit was maintained until the terminal stage of each patient. Multiple vertebral metastases are treated with posterior stabilization using various instrumentation systems that provide rigid stabilization. To choose the most appropriate procedure for each patient, the local condition of the lesion and general status of the patient, including prediction of life expectancy, should be evaluated fully. Spinal metastases develop early and are not terminal events. Therefore, not only palliative treatment but also surgical intervention should be considered for spinal metastases when indicated.

Humans↗
PubMed1994

Basic properties of an alginate impression material supplemented with chlorhexidine. I. Disinfectant effects on oral microbes.

To examine the disinfectant effects on oral microbes of an alginate impression material supplemented with 1% chlorhexidine as the aseptic ingredient (Coe Hydrophilic Gel, CHG), several cell suspensions of oral microbes (3 Gram-positives, 2 Gram-negatives and 1 yeast) were exposed to the surface of cast CHG or that of a control impression material for 5 or 30 min. They were then transferred to the surfaces of agar plates. Colony formation was estimated after culture for several incubation periods. No growth of bacteria on the plates was observed when the suspensions had been exposed to CHG even for 5 min, whereas for the control material, all the bacteria formed colonies. The yeast showed colony formation irrespective of the kind of impression material and the duration of exposure. Thus, it appears that use of an impression material supplemented with 1% chlorhexidine such as CHG may protect clinical staff and dental technicians from possible bacterial infections associated with the impression procedures.

Alginates↗
PubMed1994

Nerve fibers originating from the brain in the rat pineal complex.

The distribution of central nerve fibers in the rat pineal complex was studied by means of fluorescence- and immunohistochemistry and electron microscopy. At 7 days after bilateral superior cervical ganglionectomy (SCG-X), blue-green fluorescent (catecholaminergic) fibers and tyrosine hydroxylase- and serotonin-immunoreactive fibers originating from the brainstem were detected in the deep pineal and the pineal stalk. These fibers were not observed in the superficial pineal. In some animals, a few oxytocin-immunopositive fibers were found in the proximal portion of the superficial pineal. The nerve fibers were submicroscopically counted in transverse sections at 6 levels with an interval of about 200 microns each in the pineal stalk. The number of nerve fibers showed 3 peaks, at the proximal-most, the intermediate and the distal-most levels. On the other hand, various types of synapses, axo-dendritic, axo-axonic and axo-pinealocytic, and many free terminals, were observed in the stalk. In these synapses, the majority of presynaptic swellings contained only clear vesicles, but some of them possessed aminergic (5-hydroxydopamine- or 5,6-dihidroxytriptamine-positive) vesicles or elementary granules. The reduction in the number of nerve fibers was most conspicuous in the distal-most level after the SCG-X. Based on these results, it is supposed that the proximal peak is formed by the central fibers going further to the stalk and turning back to the brain, the intermediate peak is formed by the terminal arborizations of the central fibers, and the distal peak shows penetration of the sympathetic fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Noradrenergic fibers in the Pacinian corpuscles of the cat urinary bladder.

Pacinian corpuscles in the cat urinary bladder were studied using the hematoxylin and eosin staining, formaldehyde-induced fluorescence histochemistry, immunohistochemistry for tyrosine hydroxylase (TH) and immunoelectron microscopy. The existence of catecholaminergic nerve fibers penetrating into the corpuscles was clarified. (1) About 10 Pacinian corpuscles which were mainly located in the subserosa were found in the lower one-third portion of each urinary bladder. (2) One or two corpuscles containing blue-green fluorescent fibers were detected in each bladder. These fibers were equivalent to TH-immunopositive varicose fibers using the avidin-biotin-peroxidase complex method. (3) Thin nerve fibers containing dense-cored vesicles were found in the corpuscle by immunoelectron microscopy. These fibers spirally encompassed a swollen sensory terminal at a distance in the inner core. According to the above findings, we discuss a modulatory function of the catecholaminergic fibers in this mechanoreceptor.

Adrenergic Fibers↗
PubMed1993

The lumbar spine in spastic diplegia. A radiographic study.

Some radiological features of the lumbar spine of 84 patients with spastic diplegia were compared with 50 control subjects. The average age of the patients was 20.1 years (3 to 39). Spondylolysis of the fifth lumbar vertebra was found in 21%, four times more frequently than in normal subjects. No patient under nine years of age had spondylolysis and the frequency increased with age. The average angle of lumbar lordosis in spastic patients in the standing position was greater than in normal subjects, and increased with age. The patients had a decreased sacrofemoral angle which caused an increase in Ferguson's angle and explained the increased angle of lumbar lordosis.

Adolescent↗
PubMed1993

Distribution of pacinian corpuscles in the hand of the monkey, Macaca fuscata.

The size and distribution of pacinian corpuscles were investigated in the palmar aspect of both hands of the monkey, Macaca fuscata. Most pacinian corpuscles were located in the dermis (dermal type) and subcutaneous tissue (subcutaneous type) throughout the hand. On light microscopy there were no differences in the structure of these 2 types, although almost all the subcutaneous type had a greater longitudinal dimension than the dermal type. Corpuscles were oval or elliptical and their longitudinal and transverse dimensions varied from 156 to 2025 microns and 88 to 1240 microns, respectively. Many pacinian corpuscles were in close relation to the small blood vessels, and their diameters were as large as those of capillaries. There were 458 corpuscles (dermal type: subcutaneous type = 140:318) in the right hand and 416 (186:230) in the left hand. About 40% of the corpuscles in each hand were found in the digital region; the remainder were located in the palm. The mean number of corpuscles in each finger was 33 and they were concentrated in the distal and middle phalanges. In the palmar region, most corpuscles were localised in the 2nd and 3rd interdigital eminences and the thenar and hypothenar eminences.

Animals↗
PubMed1993

Distribution of pacinian corpuscles in the cat forefoot.

The distribution of pacinian corpuscles in the cat forefoot was investigated using celloidin sections stained with haematoxylin and eosin. The corpuscles were oval or elliptical, their longitudinal and transverse diameters being 590.0 +/- 207.6 microns and 320.0 +/- 119.6 microns. There were 667 corpuscles (mean value for 4 feet) in each forefoot, 80% of which were in the toe region and the remainder in the palmar region. The number of corpuscles was similar in both forefeet. There was no difference in light microscopic structure. Corpuscles were located (1) in the dermis and subcutaneous tissue of the skin folds covering the claw, (2) between the flexor digitorum tendon and middle phalanx, (3) in the subcutaneous adipose tissue of the metacarpal pad and (4) in short digital muscle of the carpal pad. Scattered corpuscles were found in contact with the periosteum of distal and middle phalanges and with flexor tendon sheath, and in the dermis of the palm. Corpuscles were observed to be clustered in the skin folds of the toes. Skin folds, made of dorsal hairy skin, covered the claw on both sides, with most corpuscles in contact with hair follicles and others scattered between hair follicles. Forefoot corpuscles were often in proximity with blood vessels. Corpuscles in the palmar region were seen to be arranged along the superficial palmar metacarpal nerve.

Adipose Tissue↗
PubMed1992

Experimental spondylosis in the rabbit spine. Overuse could accelerate the spondylosis.

It has been suggested that overuse can accelerate the progression of cervical spondylosis. This assumption was derived from a study examining premature onset of cervical spondylosis in patients with athetoid cerebral palsy. To clarify the relationship between overuse and structural abnormalities of the spine, repetitive extension-flexion movement was located onto young rabbit spines through electric stimulation of the trapezius muscle. Repetitive loads of 200,000 cycles caused more severe delamination of the anulus fibrosus than control at the lower cervical spine. In addition, it was associated with early osteophyte formation at the same disc level. No severe degeneration of the nucleus pulposus, however, occurred through repetitive loading. It was found that repetitive movement could accelerate the progression of structural abnormalities, such as cervical spondylosis. This result suggests that overuse is an important factor in the pathogenesis of spondylosis.

Animals↗
PubMed1992

Intraoperative measurement of lumbar spinal instability.

To justify lumbar fusion or stabilization, a quantitative assessment and definition of spinal instability are essential. To quantify spinal instability, the tensile stiffness of a motion segment (vertebra-disc-vertebra) was measured with a spinal distractor during spinal decompression surgery. Stiffness was indicated by the relationship between load and displacement between the two adjacent spinous processes where a vertebral spreader was suspended. A load-displacement curve was recorded at each step of surgical decompression and fixation while the motion segment was being distracted at a constant speed. The device used for measuring stiffness of a spinal motion segment is a lumbar spinal spreader with a load strain gauge and a displacement transducer. The stiffness of a spinal motion segment was reduced as disc degeneration developed. Degenerative spondylolisthetic discs showed the least stiffness (lowest, 3.9 N/mm; average, 5.4 N/mm). The stiffness of herniated discs, however, was relatively greater (average, 11.8 N/mm). The stiffness of normal motion segments was greater than affected segments. If the stiffness of a motion segment before decompression was graded as 100, it was reduced to 82% after partial laminectomy and facetectomy and to 65% after discectomy on average. After interbody fusion by iliac bone graft, it increased to 133% and to 184%, after Luque fixation.

Female↗
PubMed1992

Distribution of oxytocin and vasopressin neurons in the diencephalon of the Japanese horseshoe bat, Rhinolophus ferrumequinum. An immunohistochemical study.

The distribution of oxytocin (OXT) and vasopressin (VP) neurons in the diencephalon of the hibernating Japanese horseshoe bat, Rhinolophus ferrumequinum, was immunohistochemically investigated by the avidin-biotin complex method. Magnocellular OXT and VP neurons were localized mainly in the paraventricular nucleus and the supraoptic nucleus. In addition to these main nuclei, both kinds of magnocellular neurons were also found in the periventricular nucleus, perifornical area and lateral hypothalamic area. Extensively distributed parvocellular neurons containing only VP were observed in the rostral and middle portions of the suprachiasmatic nucleus. The size of OXT and VP magnocellular neurons was almost equal in the paraventricular and ventromedial supraoptic nuclei, whereas VP neurons were significantly larger than OXT neurons in the dorsolateral supraoptic nucleus. The OXT and VP cells in the ventral supraoptic nucleus showed a distinctive elliptical shape. Both OXT and VP fibers were distributed in the lateral habenular nucleus, stria medullaris thalami, lateral preoptic area, stria terminalis, and medial and supracapsular part of the bed nucleus of the stria terminalis. Moreover, OXT fibers were found in the substantia nigra, and VP fibers were noted in the nucleus reunions and the paraventricular nucleus of the thalamus.

Animals↗
PubMed1992

[Peptidergic innervation in the sinus hair follicles of several mammalian species].

In this study, the detailed distribution of peptidergic nerve fibers in the sinus hair follicle was immunohistochemically investigated by the avidin biotin-complex method using antibodies against calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) in the cat, dog, hamster, rat, mouse and guinea pig. The peptide-immunoreactive (IR) nerve fibers presented a fine varicose appearance. They entered the sinus hair follicle after penetrating the capsule (Cap) at various levels. Peptide-IR fibers in the sinus hair were classified into the 3 types described below based on their course of entry and terminal distribution. Type A: these fibers arrive at the orifice of the sinus hair follicle from superficial dermis and innervate the upper portion of the follicle. Most of them form a network around the vibrissal shaft (VS) in the outer and inner conical body (OCB and ICB, respectively), and some are distributed around the rete ridge collar (RRC) and the sebaceous gland (SG). Type B: these fibers enter the lower third of the sinus hair follicle after forming a nerve bundle together with myelinated fibers, or accompany an artery. After distribution in the trabeculae (Trab) of the cavernous sinus (CS), they form a dense plexus in the connective tissue follicle (CTF) at the level of the CS. Some ascend through the CTF and terminate at the level of the ring sinus (RS). Type C: these fibers enter the sinus hair follicle at its base. They innervate the hair papilla (HP) and the CTF of the hair bulb. CGRP and SP were detected in all types of nerve fibers in all species investigated. These peptidergic nerve fibers showed the same distribution pattern, but CGRP fibers were more numerous than SP fibers. They were distributed at high density in the OCB, ICB, CTF, ringwulst (Rw), the Trab of the CS and the HP. A moderate number of VIP- and NPY-IR fibers, mainly types B and C, were detected in these portions in the cat, dog and hamster, but few fibers were observed in other portions or in other species. Although the basic structures of the sinus hair follicle presented almost the same features as in the mammalian species, the connective tissue of the HP extended to the level of the RS in the cat, rat, hamster, and guinea pig. In these species, CGRP-, SP- and/or VIP-IR fibers extended to the top of the papillary connective tissue, and in the cat, were especially well developed.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗