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Biomedical subjects

A Ikeda

Publications and source records attributed to A Ikeda.

At least 307 records · Page 17Linked to original sources
PubMed1991

Studies on the generation of Ca2+/calmodulin-independent activity of calmodulin-dependent protein kinase II by autophosphorylation. Autothiophosphorylation of the enzyme.

The mechanism for the generation of the Ca2+/calmodulin (CaM)-independent activity of calmodulin-dependent protein kinase II (CaM-kinase II) by autophosphorylation was studied by characterizing the autothiophosphorylated enzyme, which is resistant to hydrolysis. When CaM-kinase II was incubated with adenosine 5'-O-(thiotriphosphate) at 5 degrees C, the incorporation of thiophosphate into the enzyme occurred rapidly, reaching a maximum level within a few minutes, in parallel with increase in Ca2+/CaM-independent activity. The maximum level was 1 mol of thiophosphate per mol of subunit of the enzyme, and the thiophosphorylation occurred exclusively at Thr286 in the alpha subunit and Thr287 in the other subunits of the enzyme. These results, taken together, indicate that the autothiophosphorylation of Thr286/Thr287 of each subunit is involved in the generation of the Ca2+/CaM-independent activity. The activity of the autothiophosphorylated enzyme, when assayed in the presence of Ca2+/CaM, showed the same kinetic properties as did the Ca2+/CaM-dependent activity of the original non-phosphorylated enzyme, but when assayed in the absence of Ca2+/CaM, it showed the same Vmax as the Ca2+/CaM-dependent activity but higher Km values for protein substrates. Thus, the phosphorylation of Thr286/Thr287 of the subunit of the enzyme by autophosphorylation appears to not only enhance the affinity of its substrate-binding site for the protein substrate, although it is lower than that of the enzyme activated by the binding of CaM, but also convert the active site to the fully active state.

Animals↗
PubMed1991

Scanning electron microscopy of the capillary loops in the dermal papillae of the hand in primates, including man.

The microvasculature of the skin of the hand in primates, including man, was examined by means of scanning electron microscopy of corrosion casts. In this study, the microvascular patterns and structures in different areas of the hand, and the changes in vascular patterns that occur with age, have been described. The typical structure of the capillary loops in the hand can be observed in the ball of the finger of the young adult monkey. The capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papillae, and these became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other to form the primary and secondary venous arcades. The secondary venous arcades anastomosed with each other and flowed into the subpapillary venules, which run along the dermal furrow in the fingerprint. Changes in vascular patterns with age could be observed. In the infant fingerprint, the vascular systems had not yet differentiated, especially the venous system in the dermis. In the old adult finger, the capillary loops presented complicated features deviating due to aging.

Aged↗
PubMed1991

CO2 laser-induced pain-related somatosensory evoked potentials in peripheral neuropathies: correlation between electrophysiological and histopathological findings.

Pain-related somatosensory evoked potentials (pain SEPs) following CO2 laser stimulation as well as conventional electrically stimulated SEPs (electric SEPs) were examined in 10 patients with peripheral neuropathies in whom the histopathological examination of the sural nerve was done. Results of pain SEPs showed a positive relationship with clinical impairment of pain sensation and densities of small myelinated fibers of the sural nerve. In contrast, results of electric SEPs showed a positive relationship with clinical impairment of deep and tactile sensations and with densities of large myelinated fibers of the sural nerve. Therefore, pain SEPs are considered to be generated by ascending signals mediated through nociceptive receptors and A delta fibers. The pain SEP is only one noninvasive and objective method currently available to investigate a physiological condition of the sensory pathway responsible for pain sense, and is especially useful when combined with the conventional electric SEPs.

Adolescent↗
PubMed1991

Treatment of HTLV-I-associated myelopathy with high-dose intravenous gammaglobulin.

Fourteen patients with HTLV-1-associated myelopathy were treated with high-dose intravenous gammaglobulin (IVGG). Ten received 10 g/day of IVGG and 4 received 400 mg/kg of body-weight/day of IVGG for 5 consecutive days. Improvement of spastic paraparesis was observed in 10 within 7 days of the commencement of IVGG. The therapeutic effects were sustained for more than 3 weeks in some patients. There were no side effects. Analysis of factors of relevance to the clinical improvement with IVGG showed that the beneficial response was preferentially found in patients having a high CSF titre of anti-HTLV-I antibodies, a high CSF IgG level and a marked brain MRI abnormality.

Adult↗
PubMed1991

Scalp topography of giant SEP and pre-myoclonus spike in cortical reflex myoclonus.

Scalp topography of the giant SEP and the pre-myoclonus spike demonstrated by jerk-locked back averaging was studied by using a computer-assisted evoked potential mapping technique in 5 patients with cortical reflex myoclonus. The initial positive peak of giant SEP was localized to the postcentral region contralateral to the stimulus and was associated with a negative potential field of the same latency at the frontal region in all cases. The main positive peak of pre-myoclonus spike was localized to the postcentral region contralateral to the myoclonus in 4 cases, and maximal at the midline postcentral region extending contralaterally with respect to the myoclonus in 1 case. The postcentral positive peak was associated with a frontal negativity in 2 of the 5 cases. In those 2 cases, the main components of giant SEP and the pre-myoclonus spike showed a similar scalp distribution with respect to the hand which was stimulated or myoclonic jerks were recorded from, although the latter was much smaller and less sharp than the former. These findings support our previous hypothesis that those 2 activities might be generated, at least in part, by common physiological mechanisms. In 3 other cases, however, the postcentral positive peak of the pre-myoclonus spike was not associated with a frontal negativity.

Action Potentials↗
PubMed1991

Clinical long-term results of anterior discectomy without interbody fusion for cervical disc disease.

There were 55 patients (soft disc, 21 and spondylosis, 34) who underwent anterior cervical discectomy without fusion (ACD) using an operating microscope. Discectomy of a single level was performed on 48 cases and two levels on 7. There were 37 patients with radiculopathy, and 18 patients with myelopathy or myeloradiculopathy who were followed clinically for 2-13 years postoperatively. Overall 81% of patients were improved in soft disc herniation, and no significant differences were noted between the group of radiculopathy and myelopathy. In spondylosis all but one patient reported initial relief of their preoperative symptoms; however, overall improvement was noted in only 16 patients (47%). The causes of symptomatic deterioration after ACD for spondylosis were later symptomatic recurrence in 5 patients, severe neck pain in 4, and development of new symptoms due to adjacent spur formation in 2. The authors eventually added interbody fusion in 4 cases. Cervical spine roentgenograms almost always showed a loss of height of the interspace and an anterior angulation immediately after ACD, but the alignment of the spine tended to improve with time, so that, at last follow-up, 82% had a good alignment. A spontaneous osseous fusion occurred in 74% of cases. An adjacent spur formation was observed in 3 patients with spondylosis. The most troublesome complication was neck and/or scapular pain. This pain usually subsided spontaneously, but this continued for more than 4 years postoperatively in 4 patients with spondylosis. Using an operating microscope ACD is a safe and effective procedure for patients with soft disc herniation, but the authors still prefer anterior cervical discectomy with interbody fusion for the patients with advanced spondylosis.

Cervical Vertebrae↗
PubMed1991

A testicular teratoma with rhabdomyosarcoma and seminoma.

A case of testicular mixed germ cell tumor with teratoma in a 36-year-old Japanese male is reported. Histologically, it was strongly suggested that the rhabdomyosarcoma had originated from the mesenchymal element of the teratoma. A review of the literature revealed six definitive and two possible previous cases of testicular rhabdomyosarcoma with teratoma, either with or without other germ cell malignancies. However, the present case associated with seminoma as a germ cell tumor is the first of its kind to be reported. In contrast to the poor prognosis observed in the previous cases, the present patient remains free of disease 3 years and 3 months after orchiectomy, chemotherapy and irradiation.

Adult↗
PubMed1991

A new classification of the brachial extensors in Tarsius.

The muscular system of the tarsier was first described by Burmeister (1846), who noted that brachial extensors (triceps complex) have six heads. The first three heads, respectively, correspond to the long, lateral and medial heads of the triceps brachii muscle in man. The fourth head is the anconaeus and the fifth is the dorsoepitrochlearis. Schultz (1984) divided the sixth head into two different parts (preaxial and postaxial) from the viewpoint of nerve supply. The present study found that the whole sixth head is innervated by the ulnar nerve, and we propose that it is recognized as the proximal and distal heads of the (preaxial) epitrochleoanconaeus muscle. The proximal head may have developed specially in the tarsier in addition to the distal head observed in other prosimians. It is thought to support the extension of the elbow joint and contribute to the tarsier's effective locomotion.

Animals↗
PubMed1991

Excision and end-to-end anastomosis of a fusiform aneurysm of the distal posterior inferior cerebellar artery associated with ischemia--case report.

A 35-year-old male with a sudden onset of severe vertigo and vomiting had a fusiform aneurysm of the distal portion of the left posterior inferior cerebellar artery. The symptoms were caused by cerebellar infarction probably due to an embolism from the aneurysm. The aneurysm was excised and the artery reconstructed by end-to-end anastomosis with an excellent outcome. Histological examinations showed mural thrombus but no wall dissection.

Adult↗
PubMed1991

Revascularization of the calcarine artery in moyamoya disease: OA-cortical PCA anastomosis--case report.

A 38-year-old male presented with moyamoya disease. Occlusion of the bilateral proximal posterior cerebral arteries (PCAs) resulted in homonymous 3/4 (right half and left lower quadrant) anopsia and various mental symptoms. To prevent impending cortical blindness, revascularization to the right PCA was performed by occipital artery (OA) to calcarine artery anastomosis. His neurological state was stabilized. OA-cortical PCA (calcarine artery) anastomosis is an alternative to omentum transplantation or occipital burr hole procedures for impending cortical blindness.

Adult↗
PubMed1991

[Reconstruction of hypopharynx and cervical esophagus using a free jejunal graft].

Forty-four patients with cancer in the hypopharynx and cervical esophagus underwent pharyngoesophageal reconstruction with a free jejunal graft after total removal of a tumor combined with resection of the circumferential tissues. The graft survival rate was 93.2% (41 of 44). Postoperative complications occurred in 16 patients (36.4%), which included postoperative death in one (2.3%), graft necrosis in 3 (6.8%), fistula formation in 4 (9.1%) and graft stricture in 3 (6.8%). All 3 cases of graft necrosis underwent successfully reimplantation. The mean interval time was 20.9 days until oral intake was possible. Thirty-two of 42 patients (76.2%) were able to take usual food. Esophageal speech was limited in the selected cases by this procedure. A cumulative survival rate of 5 years was 40.6% in this series. This method of reconstruction should be advocated as one of relatively safe and reliable procedures for patients with hypopharyngeal and cervical esophageal cancer.

Adult↗
PubMed1990

Pain-related somatosensory evoked potentials in cortical reflex myoclonus.

To elucidate the sensitivity to pain stimuli in patients with cortical reflex myoclonus, pain-related somatosensory evoked potentials (pain SEPs) following CO2 laser stimulation and conventional electrically-stimulated SEPs (electric SEPs) were compared in four patients with cortical reflex myoclonus. The P25 peak of electric SEPs was considerably enhanced but the P320 potential of pain SEPs was of normal amplitude in all patients. After medication, myoclonus was reduced and the amplitude of P25 was decreased, but P320 showed no change. In our previous study of the scalp distribution in normal subjects, a subcortical site, probably the thalamus, was considered to be the generator source of P320. Because most pain stimuli do not reach the cortex, patients with cortical reflex myoclonus are not sensitive to pain stimuli and P320 in pain SEPs is not enhanced.

Adolescent↗
PubMed1990

Comparative anatomy of the arterial system of the foot in primates. 1. Macaque.

Using stereoscopic angiography, the entire arterial system of the foot of the macaque was analyzed. The arteria saphena, instead of the a. tibialis anterior, reaches the dorsum of the foot, and its branches supply most of the foot. The dorsal arteries are dominant as far as the metatarsal spaces of the lateral four toes. The a. metatarsea dorsalis II showed a tendency to be the single dominant artery and to give rise to even the a. digitalis communis plantaris IV through the catella plantaris distalis. This tendency was observed more clearly in other macaques species than the Japanese monkey. The perforating branch at the second proximal metatarsal space forms the arcus plantaris profundus, which is accompanied by the deep branch of the nervus plantaris lateralis. Beneath the arch, the catella plantaris proximalis is formed on the metatarsal bones among the perforating branches of the aa. metatarseae dorsales. The a. tibialis posterior forms the arcus plantaris superficialis, whose thin branches commonly enter the aa. digitales communes plantares.

Angiography↗
PubMed1990

Cortical tremor: a variant of cortical reflex myoclonus.

Two patients with action tremor that was thought to originate in the cerebral cortex showed fine shivering-like finger twitching provoked mainly by action and posture. Surface EMG showed relatively rhythmic discharge at a rate of about 9 Hz, which resembled essential tremor. However, electrophysiologic studies revealed giant somatosensory evoked potentials (SEPs) with enhanced long-loop reflex and premovement cortical spike by the jerk-locked averaging method. Treatment with beta-blocker showed no effect, but anticonvulsants such as clonazepam, valproate, and primidone were effective to suppress the tremor and the amplitude of SEPs. We call this involuntary movement "cortical tremor," which is in fact a variant of cortical reflex myoclonus.

Aged↗
PubMed1990

Familial occurrence of moyamoya disease with intracranial hemorrhage--report of two cases.

The authors report an instance of familial moyamoya disease involving a 47-year-old female and her 18-year-old daughter, both of whom initially presented, within a 1-year period, with intracranial hemorrhage. Cerebral angiography showed the typical features of moyamoya disease. The mother, whose disease was more advanced, underwent superficial temporal-middle cerebral artery bypass, with satisfactory results. Human leukocyte antigen typing was performed in both cases. The pertinent literature is reviewed.

Adolescent↗
PubMed1990

[A clinical trial to determine whether intravenous aminophylline is indispensable in the treatment of status asthmaticus].

In Japan, intravenous aminophylline (AMP) is considered as the first treatment of choice for status asthmaticus, whereas inhaled beta 2-agonist is considered to be of no value for acute severe asthma. To determine the optimal therapy for acute asthma, the authors clinically investigated bronchodilating effects and the clinical role of aerosolized beta 2-agonist inhalation and intravenous AMP in 55 patients with status asthmaticus. Patients were classified into two groups treated without intubation and with artificial ventilation. Intravenous steroid (equivalent to 4 mg/kg of hydrocortisone) was administered in all cases. Further, all patients were randomly divided into two subgroups according to treatment regimen, i.e. repeated inhalation of aerosolized beta 2-agonists only, and combined with intravenous AMP. In all groups, the duration of treatment was significantly shorter in the subgroups treated with repeated aerosolized beta 2-agonist inhalation than those treated with intravenous AMP. The failure of intravenous AMP to effect more rapid or profound improvement both in objective and subjective parameters suggested that inhaled beta 2-agonist with intravenous steroid should be a rational choice in the initial treatment of acute asthma. Moreover, inhaled beta 2-agonist used optimally produces good bronchodilation several times greater than that produced by intravenous AMP. We concluded that repeated inhalation of aerosolized beta 2-agonists is the drug of choice combined with intravenous steroid regardless of the severity of attacks for short-term therapy of acute severe asthma, and that intravenous AMP may have only minor bronchodilating effects.

Administration, Inhalation↗
PubMed1990

[Reproducibility of peak expiratory flow rate measured at home].

In 8 stable patients with chronic asthma, the reproducibility of peak expiratory flow rate (PEFR) measured and recorded 4 times per day for longer than 1 month at home and at work was assessed. Average %PEFRs of individuals through the periods observed were higher than 80%, and coefficients of variation were less than 10% regardless of the time measured. This suggested that a decrease in %PEFR more than 10% reflects early phase of deterioration of airways narrowing and frequent measurement of PEFR is essential for long-term management and for self-assessment of chronic asthma.

Adolescent↗