Biomedical subjects

K Shinomiya

Publications and source records attributed to K Shinomiya.

At least 91 records · Page 5Linked to original sources

PubMed1996

Experimental study on nerve regeneration through the basement membrane tubes of the nerve, muscle, and artery.

We evaluated neurotization after transplantation with lyophilized nerves, muscles, and arteries, and examined the possibility of practical application of long bridging grafts. Grafts of 10 mm and 25 mm of lyophilized nerves, muscles, and arteries harvested from Fisher rats were transplanted to the sciatic nerves of recipient Lewis rats. The histological changes undergone by short grafts were observed at weekly intervals. The sham-operated and isograft groups were used to compare the results of long grafts. In both the nerve and muscle-graft group, regenerated axons grew out through the residual basement membrane tube. But in the muscle graft group, phagocytosis of myofibril debris took longer than that of degenerated axons. No statistical differences were found between results of TSI, induced EMG, and quantitative analysis of myelinated axons in the nerve and muscle graft groups. No neurotization was noted in the long artery graft. In long grafts, laminin found on the basement membrane may not be sufficient to accelerate neurotization, and arteries should not be used for tubulization.

Animals↗

PubMed1996

Morphological observations of megakaryocytic emperipolesis in the bone marrow of rats treated with lipopolysaccharide.

A morphological examination was performed on megakaryocytic emperipolesis containing neutrophils in the rat bone marrow induced by intravenous administration of lipopolysaccharide (LPS). Ultrastructurally, the engulfed neutrophils appeared to lie in the demarcation membrane system (DMS) of megakaryocytes. Intact neutrophils generally migrated from DMS into the lumen of vascular sinus across the endothelium of sinus wall. However, some neutrophils showed characteristics of apoptosis, and DNA fragmentation was detected in these cells by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling method. Thus, the cell death of neutrophils engulfed by megakaryocytes was thought to be apoptosis. The present results suggest that megakaryocytes contribute to random selection of an excess of neutrophils in the bone marrow of rats treated with LPS.

Animals↗

PubMed1996

Inhibitory effect of the NMDA receptor antagonist, dizocilpine (MK-801), on the development of morphine dependence.

We investigated the effect of a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imin ehydrogen maleate (dizocilpine, MK-801), on hippocampal norepinephrine release in morphine-treated rats in order to clarify the relationship between NMDA receptors and the development of morphine dependence. Naloxone hydrochloride injected subcutaneously (s.c.) into morphine-dependent rats, induced an immediate increase in hippocampal norepinephrine release, which was associated with a typical morphine withdrawal syndrome. The increased norepinephrine levels persisted for at least 2 hr, even after the disappearance of the behavioral withdrawal syndrome. This striking effect of naloxone on hippocampal norepinephrine release was dependent on the duration of the intracerebroventricular (i.c.v.) morphine infusion. Pretreatment with dizocilpine (s.c.) before naloxone challenge reduce the rate of the rise in hippocampal norepinephrine release induced by naloxone in morphine-treated rats. Concurrent infusion (i.c.v.) of dizocilpine and morphine decreased the level of hippocampal norepinephrine release after a naloxone challenge. Both pretreatment with dizocilpine (s.c.) before naxolone injection and infusion (i.c.v.) of dizocilpine suppressed rearing and teeth-chattering signs, but not wet-dog shakes in morphine-treated rats. These results suggest that dizocilpine attenuates the development of morphine dependence through NMDA receptors, and thus that interaction between opioid receptors and NMDA receptors may be involved in the development of morphine dependence.

Analysis of Variance↗

PubMed1996

Inverse relation between vertebral body deformity and intervertebral disk narrowing in lumbar spine of elderly women.

To investigate the relation between vertebral body deformity and disk narrowing in the lumbar spine of elderly patients, a longitudinal radiographic study of 56 aged women was retrospectively performed. We measured disk areas and body heights on two lateral lumbar radiograph sets obtained with an average interval between examinations of 10 years. The absolute values of disk areas on first examination and the rates of change of area of disks adjacent to nondeformed bodies were smaller than the corresponding values for the deformed bodies. Conversely, deformed bodies tended to have normal or expanded disks regardless of the mode of deformity. Despite the small number of subjects studied, our findings suggested that an inverse relation may exist between vertebral body deformity and disk narrowing.

Aged↗

PubMed1996

Urodynamic and electrophysiologic study of the urinary disturbances caused by cervical myelopathy.

Urinary disturbance is one of the significant symptoms of cervical myelopathy. To make the diagnosis of urinary disturbance, preoperative urodynamic studies and evoked spinal cord potentials (ESCPs) recording were performed on 60 surgical patients with cervical myelopathy. Half (30) of this group complained of urinary disturbance, and 22 (37%) were diagnosed as having neurogenic bladder. The presence of neurogenic bladder was closely correlated with severe limb symptoms and relatively slow ESCP velocity. It was confirmed that neurogenic bladder was caused by severe spinal cord damage. However, for 47% of the patients with urinary complaints, findings of urodynamic examinations were negative; these patients probably had pathologic or psychosomatic factors other than neurogenic bladder due to cervical myelopathy. The prognosis of the neurogenic bladder appears to be influenced by irreversibility of the spinal cord lesions.

Aged↗

PubMed1996

Monitoring of anterior cervical spinal cord function.

Anterior surgery is frequently chosen for treatment of cervical myelopathy. However, intraoperative spinal cord recording has rarely been used to monitor the function of the ventral columns. We report a method of monitoring evoked spinal cord potentials useful for detection of minor injury of the anterior spinal cord. Evoked spinal cord potentials elicited in cats by thoracic spinal cord and labyrinth stimulation were studied. Evoked intraspinal field potentials recorded after labyrinth stimulation were confirmed to originate from the vestibulospinal tract in the ventral columns. Low-amplitude potentials were recorded from the posterior epidural space. However, this method has not been used clinically because of difficulty in obtaining selective stimulation in humans. Spinal cord potentials evoked by thoracic stimulation were recorded from the anterior and posterior epidural spaces. The amplitude of the potentials was large enough to permit quantitation of neural function. We confirmed that anterior recording was more sensitive in detecting ventral column injury than posterior recording was. Based on these findings, we used anterior recording from the disc clinically for anterior spinal cord monitoring during anterior cervical surgery.

Acoustic Stimulation↗

PubMed1996

A cadaveric study on the stability of lumbar segment after partial laminotomy and facetectomy with intact posterior ligaments.

This study aimed to biomechanically investigate a change in the stability of decompressed segments in the degenerative lumbar spine. Cyclic loading tests to the cadaveric spinal unit were conducted in compressive and bending directions with a stepwise resection of the posterior elements such as wide fenestration (partial laminotomy), unilateral and bilateral facetectomy with the intact supra- and interspinous ligaments and spinous process. Flexion stability did not decrease significantly, and may reflect the fact that the aforementioned ligamentous structures were preserved throughout the resection process. After wide fenestration, the loss of compression stiffness amounted to only half that of bilateral facetectomy, and extension stiffness dropped to this same level. Lateral bending stiffness was maintained until unilateral facetectomy was performed. We recommend restricted decompression surgeries for a single-level central stenosis in the degenerative lumbar spine.

Aged↗

PubMed1995

Spinal cord monitoring of the ventral funiculus function. Analysis of spinal field potentials after galvanic vestibular stimulation.

STUDY DESIGN: This study was designed to examine the possibility of a new spinal cord monitoring method using galvanic vestibular stimulation to monitor the function of the ventral funiculus of the spinal cord. OBJECTIVES: To settle the problems of previous monitoring methods by using galvanic vestibular nerve stimulation, which is highly selective for monitoring the function of the ventral funiculus of the spinal cord. SUMMARY OF BACKGROUND DATA: Although various spinal cord monitoring methods have been used, there are still problems because potentials recorded by these methods do not reflect selectively the function of the ventral funiculus of the spinal cord, which is vulnerable during anterior spinal surgeries. METHODS: In anesthetized cats, field potentials evoked by galvanic stimulation of the labyrinth were recorded from the epidural space of the spinal cord. The origin of these potentials was determined by mapping field potentials from within the upper cervical spinal cord using a micropipette and by examining the effect of sectioning the brainstem on the evoked potentials. RESULTS: The spinal cord potentials evoked by galvanic stimulation between the bilateral labyrinths could be recorded from the epidural space, and these potentials mainly originated from the ventral and ventromedial funiculus of the spinal cord. The latency and intraspinal distribution of the evoked potentials and the effect of sectioning the medial longitudinal fascicle on the evoked potentials indicated that the earliest component of the evoked potentials reflects mainly the activity of the vestibulospinal tract. CONCLUSIONS: Recording spinal cord potentials evoked by galvanic vestibular stimulation from the epidural space appears to be a potential technique to monitor the functional state of the ventral funiculus during anterior spinal surgeries.

Animals↗

PubMed1995

A new method of multisegment motor pathway monitoring using muscle potentials after train spinal stimulation.

STUDY DESIGN: Evoked muscle and nerve action potentials after spinal stimulation for intraoperative monitoring were investigated using a modified stimulation technique. Animal experiments and clinical application were performed. OBJECTIVES: To contrive a useful method of intraoperative motor pathway monitoring under inhalation anesthesia. SUMMARY OF BACKGROUND DATA: Many different kinds of procedures have been reported. No reliable method that reflects pure motor tract function has been established. METHODS: Characteristic of our stimulating technique was the use of numbered consecutive pulses ("train stimulation"). In 16 cats, optimum condition of train stimulation, effects of anesthetic agents, and conductive pathway were examined. In 35 patients, muscle potentials evoked by train stimulation were recorded, and clinical usefulness was evaluated. RESULTS: In the experimental study, the optimum stimulus condition was determined 1 ms interstimulous interval train of five pulses. Conductive pathway of this method was identified as a lateral column by selective spinal cord transection. In the clinical application, by using train stimulation, multisegmental muscle potentials were obtainable even using inhalation anesthetics. CONCLUSIONS: The facilitative effects of train stimulation, attributed to temporal summation, are considered to overcome the suppression of inhalation anesthesia. The evoked muscle potentials by train spinal stimulation reflect the functions of pure motor tract and is the only, extremely efficient method for intraoperative motor pathway monitoring.

Action Potentials↗

PubMed1995

In utero and lactational exposure of the male rat to 2,3,7,8-tetrachlorodibenzo-p-dioxin: impaired prostate growth and development without inhibited androgen production.

To determine whether in utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure decreases male rat accessory sex organ weights during postnatal development secondary to decreases in testicular androgen production or changes in peripheral androgen metabolism, pregnant Holtzman rats were administered a single dose of TCDD (1.0 microgram/kg, po) or vehicle on Gestation Day 15 and offspring were exposed via placental and subsequent lactational transfer until weaning on Postnatal Day (PND) 21. Between PNDs 21 and 63, circulating androgen concentrations and intratesticular androgen content tended to be decreased by in utero and lactational TCDD exposure, but in most cases decreases were not statistically significant. In vitro human chorionic gonadotropin-stimulated testosterone production by decapsulated testes from TCDD-exposed animals was not different from control, although 5 alpha-androstane-3 alpha,17 beta-diol production was decreased on PNDs 32 and 49 and increased on PND 63. Taken together, these results imply that in utero and lactational TCDD exposure can cause subtle decreases in testicular androgen production. However, the biological relevance of these reductions is equivocal because they do not correlate temporally with one another or with decreases in androgen-dependent male accessory sex organ weights. Of the male accessory sex organs, ventral prostate (VP) and dorsolateral prostate (DLP) were the most severely affected. Between PNDs 21 and 63, relative VP and DLP weights were decreased to 65-84% and 57-80% of control, respectively, and the magnitude of observed decreases was greatest at early times. In contrast, relative weights of the seminal vesicle and coagulating gland ranged from 80 to 104% of control, and the magnitude of observed decreases was greatest at later times. The sensitivity of the prostate to TCDD could not be explained by tissue-specific decreases in dihydrotestosterone (DHT) concentrations. Although VP DHT concentration was decreased to 63% of control on PND 21, DHT concentration was not decreased in the VP between PNDs 32 and 63 or in the DLP at any time. We conclude that in utero and lactational TCDD exposure selectively impairs rat prostate growth and development without inhibiting testicular androgen production or consistently decreasing prostate DHT concentration.

Androgens↗

PubMed1995

Reduced neck movement after operations for cervical spondylotic myelopathy.

Complaints resulting from reduced neck movements were investigated in 50 patients who had operations for cervical spondylotic myelopathy. Seventy per cent had difficulty in performing 11 basic movements of daily living. Lateral bending or rotation were more difficult than flexion and extension. To look backwards was the most difficult movement. Complaints were highest among those in whom more than three levels of fusion had been carried out.

Activities of Daily Living↗

PubMed1995

Dissociated motor loss in forearm and hand muscles: case report.

A 27-year-old man was diagnosed with the unilateral dissociated motor loss of the forearm and hand muscles. His medical image findings were completely different from those of other reports such as so called flexion myelopathy (abnormal anterior displacement of the dura mater and the spinal cord against the posterior wall of the vertebral body in neck flexion). Our patient demonstrated lateral shift of the spinal cord to the right attributed to high thoracic scoliosis and disk herniation at the level of C6-7. The right side of the spinal cord was compressed between the disk herniation and the right lamina. In this condition, circulatory insufficiency probably occurred and resulted in damage of the anterior horn, which was selectively vulnerable for ischemia in the spinal cord.

Adult↗

PubMed1995

Isolated muscle atrophy of the distal upper extremity in cervical spinal cord compressive disorders.

The purpose of this article is to clarify one mechanism of muscular atrophy of the distal upper extremity that we attribute to cervical compression (Hirayama-type amyotrophy) by medical imaging and anatomical studies of the cervical spine. Five young male patients (mean age: 22.6 years) with this disorder showed characteristic findings to include an abnormal anterior displacement of the posterior dura wall in flexion that resulted in an anteroposterior compression of the spinal cord segment from C7 to C8. To identify an anatomical relationship to this disorder, the lower cervical spine was studied using 11 embalmed adult human cadavers. Abundant posterior epidural ligaments were observed between the posterior dura mater and the ligamentum flavum. Posterior epidural ligaments in the cervical spine have not been reported previously. The anterior displacement of the dura mater may be attributed to a lack of and/or insufficiency of the posterior epidural ligaments.

Adolescent↗

PubMed1994

Morphology of C5 ventral nerve rootlets as part of dissociated motor loss of deltoid muscle.

STUDY DESIGN: This study analyzed anatomic characteristics of cervical ventral rootlets. After total vertebrectomy, detailed morphology of the ventral rootlets was studied from the anterior. SUMMARY OF BACKGROUND DATA: The clinical study showed the predominance of ventral root lesion. There are few studies concerning the morphologic pathogenesis of cervical amyotrophy and detailed cervical ventral rootlet anatomy. METHODS: Thirty-six embalmed adult human cadavers were studied. The measurements for the ventral rootlets of C5 to C8 were made as follows: 1) angle between the rootlet and spinal cord, 2) longitudinal width of the ventral rootlet origin, and 3) length of the ventral rootlets. RESULTS: The C5 ventral rootlets were shorter and issued more obtusely from the cervical spinal cord than lower rootlets. The spinal cord segment of the deltoid muscle, indicated by the longitudinal widths of the C5 and C6 ventral rootlet exits from the spinal cord, were wider than the C7 and C8 segments. Preforaminal anterior compression at the C4-C5 disc level might affect the lower part of the C5 ventral rootlets and upper part of the C6 ventral rootlets. CONCLUSION: Short C5 ventral rootlets appeared to become taut and easily injured by hemilateral anterior compression. Spinal cord lesion resulting from localized anterior compression at the single disc level might not play as important a role in the pathogenesis of dissociated motor loss of the deltoid muscle because of the wider spinal segments of C5 and C6.

Aged↗

PubMed1994

Structural characterization of porcine enteropeptidase.

Enteropeptidase (EC 3.4.21.9) is a key enzyme in the intestinal digestion cascade responsible for the conversion of trypsinogen to trypsin, which then activates various pancreatic zymogens. In order to structurally characterize the enzyme, we purified the enzyme from porcine duodenal mucosa and showed that it consists of three polypeptide chains, which we named "mini" chain (M chain), light chain (L chain), and heavy chain (H chain) in order of increasing molecular size. Based on their NH2-terminal sequences, a cDNA clone for porcine enteropeptidase was isolated and analyzed. The clone was 3597 base pairs long, which encoded 1034 amino acid residues of a single-chain precursor form of enteropeptidase. The precursor contained an additional NH2-terminal 51-residue sequence including a putative internal signal sequence, followed by the M chain (66 residues), the H chain (682 residues), and the L chain (235 residues) in that order. The H chain had regions partially homologous in sequence with low density lipoprotein receptor and complement components. On the other hand, the L chain was highly homologous with the catalytic domains of trypsin-like serine proteinases. The structural model of the L chain suggests that the sequence, Arg885-Arg-Arg-Lys888, is probably involved in the unique substrate specificity of the enzyme, preferring acidic amino acid residues at the P2-P5 sites.

Amino Acid Sequence↗

PubMed1994

Neuroradiologic and electrophysiologic assessment of cervical spondylotic amyotrophy.

Dissociated motor loss due to cervical spondylosis and disc herniation was evaluated in 10 patients who presented with left deltoid paresis in the absence of sensory deficits or myelopathy. All of these cases underwent cervical anterior decompression. Based on magnetic resonance imaging, computed tomography myelography, and computed tomography discography, patients were divided into two pathologic types: The first showed focal bony spur and disc herniation with axial cord rotation and nerve root compression, and the second demonstrated ventral cord flattening. Electrophysiologic studies included evoked spinal potentials, motor evoked potentials, and evoked muscle action potentials. Motor evoked potentials, recorded epidurally from the ventral aspect of the thecal sac and the nerve root within the anterior discectomy or vertebrectomy sites, proved clinically most useful. Combining the latest available neuroradiologic and electrophysiologic information, 4 types of neural injury associated with deltoid pareses were identified in the 10 patients. The first included isolated C5 nerve root lesions; the second, C6 nerve root lesions; the third, both C5 and C6 nerve root lesions, and finally, intrinsic cord pathology.

Adult↗

PubMed1994

Giant sacral cysts with neurogenic bladder.

Most sacral cysts are accidentally found on lumbar myelograms and are usually asymptomatic. We operated on two patients with giant sacral cysts from S3 nerve roots who complained of neurogenic bladder and perianal sensory disturbance as well as buttock pain. Morphology of these cysts and intraoperative electrophysiological findings of nerve conduction block showed two kinds of pathogenesis causing these neurological symptoms. One was attributed to conduction block of more caudal sacral nerves squeezed between these giant sacral cysts and the other was due to degeneration of nerve root fibers involved in the sacral cyst walls. Postoperatively, buttock pain and perianal hypesthesia were resolved, but the neurogenic bladder showed only partial recovery.

Adult↗

PubMed1994

[Experimental exposure to carbon monoxide in rats (I)--Relation between the degree of carboxyhemoglobin saturation and the amount of carbon monoxide in the organ tissues of rats].

This paper presents the correlation between the degree of carboxyhemoglobin saturation and the amount of carbon monoxide (CO) in the organ tissues of rats. The experiment was performed to make male rats of the Sprague Dawley strain inhalate air containing 0.195% carbon monoxide in the exposure apparatus. Five experimental groups of various degrees of carboxyhemoglobin saturation were made by controlling the length of exposure time to CO gas (0.195% CO in air). After exposure to CO gas, the rats were killed by nitrogen gas. The carboxyhemoglobin saturation levels (COHb%) of each of the experimental group were 12.2 +/- 1.16, 31.6 +/- 2.38, 42.4 +/- 2.11, 52.3 +/- 1.81 and 73.6 +/- 3.01. Immediately following the death of the rats, blood from the right ventricle and several organ tissues were collected and analysed for CO by means of an Ecolyzer Model 2600 (CO analyzer). The order of CO amount in their organ tissues in decreasing order was blood > spleen divided by liver > lung > kidney divided by myocardium > encephalon divided by pectoral muscles. There was a good positive correlation between the degree of carboxy hemoglobin saturation (y%) and the CO content (x microliter/g) in the organ tissues examined. The results obtained were as follows: [table: see text] This report might be useful for deciding the cause of death for a burned cadaver who was discovered in a fire.

Animals↗