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Biomedical subjects

K Mochida

Publications and source records attributed to K Mochida.

At least 55 records · Page 3Linked to original sources
PubMed1998

Merkel cell carcinoma, Bowen's disease and chronic occupational arsenic poisoning.

We diagnosed a unique case of Merkel cell carcinoma (MCC) coexisting with Bowen's disease on the sole of the foot of a 72-year-old man who had worked for about 4 years in a factory handling inorganic arsenic. He had a past history of arsenical keratosis and multiple Bowen's disease. The tumour first appeared as a reddish macule and then showed marked growth over the next month. The tumour was excised and the specimen was examined histopathologically. The tumour consisted of two components: a group of atypical cells representing Bowen's disease in the epidermis and another group of atypical cells with a trabecular pattern characteristic of MCC in the dermis. Neither group of cells showed transitional findings, and the tumour elements were divided by a clear basement membrane. The tumour cells in the dermis were positive for neurone-specific enolase, and on electron microscopy had dense core granules in the cytoplasm. Inorganic arsenic can cause various cutaneous neoplasms, but to our knowledge, this is the first report of a case of MCC associated with Bowen's disease.

Aged↗
PubMed1997

Evaluation of motor function during thoracic and thoracolumbar spinal surgery based on motor-evoked potentials using train spinal stimulation.

STUDY DESIGN: Using compound muscle action potentials after train spinal stimulation, intraoperative motor functional monitoring was performed during thoracic and thoracolumbar spinal surgery. OBJECTIVES: This study was designed to clarify the clinical usefulness of train spinal stimulation and to determine the critical point of compound muscle action potential change at which neurologic injury during surgery occurs. SUMMARY OF BACKGROUND DATA: In 1995 the authors reported that train spinal stimulation allows for the recording of compound muscle action potentials, even in animals and humans under general anesthesia. The facilitative effect of train stimulation overcomes the suppressive effects of anesthetics and allows potentials to pass through synapses, thereby enabling a reliable recording of lower extremity compound muscle action potential. METHODS: Multisegmental recording of compound muscle action potentials after train spinal stimulation was conducted on 34 patients Undergoing surgical treatment for thoracic or thoracolumbar lesions. During surgery, train stimuli (5 pulse, Interstimular Interval: 1 ms) were administered using an epidural electrode introduced transcutaneously. Compound muscle action potentials were recorded from a total of 128 muscles. Anesthesia was maintained using fentanyl and propofol or nitrous oxide with or without isoflurane. Muscle relaxation was attained mainly by controlled infusion of vecuronium bromide. The percent occurrence of recordable compound muscle action potentials was determined, and the potential changes were correlated with changes in muscle strength. RESULTS: Compound muscle action potentials could be recorded from at least one muscle in 94% of the patients, even in most patients with severe motor dysfunction. The compound muscle action potential changes before and after surgical maneuver were divided into four grades. All compound muscle action potential changes in deteriorated muscles belonged to Grade 2 (a 10% latency delay) or Grade 3 (disappearance). CONCLUSIONS: The success rate in obtaining muscle potentials was greatly enhanced when all of the following methods were used: train spinal stimulation, anesthetic with weak suppressive effect, multiple muscle recording, and percutaneous introduction of epidural electrode. The critical point of compound muscle action potential change should be defined as a 10% latency delay or disappearance. Multisegmental muscle potential after train spinal stimulation is the most appropriate method for thoracic and thoracolumbar spinal surgery.

Adult↗
PubMed1996

In vitro fertilization and microinsemination with round spermatids for propagation of nephrotic genes in mice.

The ICGN is an inbred strain of mice with a hereditary nephrotic syndrome of an unknown cause. The disease progresses to renal failure, resulting in the deterioration of the systemic condition and in a drastic reduction of reproductive capacity. The present study was undertaken to determine if in vitro fertilization (IVF) and microinsemination using round spermatids could ameliorate the reduced fertility of ICGN mice. Mature oocytes (9.4 +/- 1.1 per mouse) were obtained from PMSG/hCG-primed females 2 to 5 mo of age. When spermatozoa from males aged 3 to 4 mo was used for IVF, a high fertilization rate (82.6%) was achieved and a high rate of embryos developed into blastocysts (92.6%). When spermatozoa from males aged 5 to 7 mo was used, the rates of fertilization and development to blastocysts were significantly lower (63.9 and 47.1%, respectively; P < 0.001). However, the production rate of offspring after embryo transfer was satisfactory irrespective of the age of males (59.1%). When males older than 9 mo were used, no fertilization was achieved due to the very poor motility of the spermatozoa. Microinsemination techniques with round spermatids (electrofusion and intracytoplasmic injection) resulted in the production of normal offspring from the older males, including one azoospermic case. These findings indicate that a conventional IVF technique and microinsemination using round spermatids can be used for propagating mutant genes which cause poor reproductive ability in mice.

Journal Article↗
PubMed1996

Fixed drug eruption due to colchicine.

A case of fixed drug eruption due to colchicine was reported. A 31-year-old man developed a dark purplish-red round macule on the glans penis 5 h after taking 2.5 mg of colchicine. An oral challenge test with 0.5 mg of colchicine provoked flare-up of the eruption.

Adult↗
PubMed1996

Lysosomal glycolipid storage in the renal tubular epithelium in mastomys (Praomys coucha).

The renal proximal tubular epithelium of MCC strain of mastomys (Praomys coucha) exhibited a number of cytoplasmic vacuoles after conventional paraffin-embedding procedures. These vacuoles were strongly PAS-positive in cryostat sections. Ultra-structurally, they were double membrane-bound structures filled with myelin figures and acid phosphatase-positive electron-dense matrix. Immunofluorescent microscopy revealed that these structures contained GM2 ganglioside. Other tissues or organs were histologically normal. Mating experiments indicated that the ganglioside storage in MCC mastomys is inherited as an autosomal recessive trait.

Animals↗
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↗
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

Six-membered cyclic phosphonate GABA antagonists, 2,5-disubstituted 1,3,2-dioxaphosphorinanes.

The trans isomer of 2-(4-bromophenyl)-5-tert-butyl-2-thiono-1,3,2-dioxaphosphorinane competitively inhibited the specific binding of 35S-tert-butylbicyclophosphorothionate to rat brain membranes with an IC50 value of 0.52 microM, and showed insecticidal activity against houseflies with an LD50 value of 2.4 micrograms/fly. This compound and its analogues acted as noncompetitive GABAA receptor antagonists (NGRAs), and phosphorus-containing cyclohexane skeletons may prove useful for the design of novel NGRAs.

Animals↗
PubMed1995

Initial phase of an inflammatory reaction in testis caused by experimental testicular autoimmunity in the Nile tilapia, Oreochromis niloticus.

In order to study the pathogenesis of the testicular autoimmunity induced by the immunization with allogeneic testis homogenate (ATH) mixed with Freund's complete adjuvant (FCA) in the Nile tilapia Oreochromis niloticus, the initiation of inflammatory reactions in the testis was ultrastructurally investigated and seminal plasma was analyzed for presence of autoantigens. In the seminal plasma, mainly 120 kD and 80 kD autoantigens were identifiable by Western blotting with tilapia antisperm autoantibody. Eight weeks after injection with FCA, globate structures, possibly originating from FCA, were large and distended the interstitium where the inflammatory reactions were more frequently recognizable. The globate structures may be one of causes to break the blood-testis barrier, and the inflammatory reaction may be due to the leakage of soluble autoantigens from the lumen. In the interstitium, several kinds of immunocompetent cells formed masses which were mainly composed of lymphocytes, macrophages, eosinophils and plasma cells. We suggest that the inflammatory reactions in fish caused by the immunization with ATH+FCA are initiated by sensitization of the immunocompetent cells with testicular autoantigens, the 120 kD and 80 kD autoantigens in the seminal plasma are two of them, leaking from the lumen because of the provable effect of FCA. These initial reactions were then amplified by cellular and humoral immunity.

Animals↗
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

Physical biochemical properties of IgM from a teleost fish.

Teleost fish are able to produce IgM class antibody, as are other vertebrates. When the teleost fish Oreochromis niloticus was immunized with bovine serum albumin (BSA), it produced antibody to BSA with an average avidity of 7.4 x 10(8)/M. Thus, dissociation of antigen-antibody complexes only occurred at conditions of < pH 2.5, > pH 11, > 4M NaI or > 4M urea, demonstrating high stability of the complex. Western blot analyses further showed the high specificity of the antibody to BSA. In contrast to mammals, when the fish was challenged with multiple protein antigens, it produced antibody only to the major component but not to others. The antibody generated to a specific antigen accounted for up to 1.1% of whole serum protein or 7.0% of whole immunoglobulin. We conclude (1) the systemic antibody response in teleost fish may be an 'all or nothing' response, which is different from that in mammals; (2) the quality (specificity and affinity) of the antibody produced is similar to that of mammals. The findings not only reveal a quite different strategy of immune response in fish, but also raise the possibility of technical application.

Animals↗
PubMed1993

Organ culture of human hair follicles in serum-free medium.

Human hair follicles were cultured in serum-free media at 31 degrees C in an atmosphere containing 95% O2 and 5% CO2. Results showed that the length of the cultured hair increased time dependently for 96 h. Histological findings revealed that the hair germinative cells maintained their normal morphology throughout the 96 h culture period. DNA synthesis in the hair bulb also increased time dependently for 96 h. Autoradiographs of 3H-thymidine-labelled follicles indicated that they were localized in the germinative cells below Auber's critical line. The effects of minoxidil sulphate on DNA synthesis in this culture system were concentration dependent. Minoxidil sulphate at concentrations of 10(-10), 10(-9) and 10(-8) M significantly increased DNA synthesis compared with DNA synthesis in the control medium. Autoradiographs of the follicles cultured in 10(-10) M minoxidil sulphate showed that 3H-thymidine localized primarily in the germinative cells below Auber's critical line. These results suggest that this organ culture system may be useful for studying DNA synthesis by hair germinative cells in serum-free media.

Culture Media, Serum-Free↗