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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 937 records · Page 52Linked to original sources
PubMed1987

Descending and segmental spinal pathways differently regulate contractions of antagonistic muscles of frogs in vitro.

A comparison of fibres descending through the ventral column and segmental afferent fibres was carried out using an isolated frog spinal cord-nerve-muscle preparation with a pair of antagonistic muscles. The m. tibialis anterior (TIB) was contracted with stimulation of the ventral column much stronger than with that of the dorsal root (DR). Contraction of the m. gastrocnemius (GAS) was selectively induced with DR stimulation. These results suggest that the descending fibres and segmental afferent fibres preferentially regulate contractions of the flexor (the TIB) and the extensor (the GAS), respectively. Effects of alpha-aminoadipate, methysergide and LSD were also examined.

2-Aminoadipic Acid↗
PubMed1987

In vitro studies of the effects of naloxone on the root potentials in the frog spinal cord: enkephalin-like effect on the recurrent presynaptic inhibition.

Specific binding of [3H]naloxone was demonstrated in the frog spinal cord. In isolated and perfused frog spinal cord, naloxone increased the spontaneous discharges of the ventral root. Naloxone decreased the ventral root-dorsal root potential (VR-DRP) in a dose-dependent manner, and inhibited presynaptic inhibition of the ventral root reflex. Methionine-enkephalin also decreased the VR-DRP, and naloxone partially antagonized this effect. These results suggest the existence of enkephalinergic control of spinal motor activities and that naloxone has a partial agonistic effect in the frog spinal cord.

Animals↗
PubMed1987

Leydig cells within the aspermatogenic seminiferous tubules.

Cells identical to Leydig cells were found within a peritubular boundary layer and even inside a basal lamina of seminiferous tubules in three male patients (two with inguinal cryptorchism and one with infertility). The seminiferous tubules of all patients showed a moderate to marked thickening of the boundary layer and a complete loss of spermatogenic cells. The "ectopic Leydig cells" were characterized by the presence of Reinke crystals or an extensively developed smooth endoplasmic reticulum. These cells were believed to have differentiated in situ from myoid cells within the boundary layer and also to have invaded from the interstitial tissue in the form of mature Leydig cells. The occurrence of ectopic Leydig cells appeared to parallel the extent of loss of the Sertoli cells and also that of the thickening of the boundary layer. The functional significance of the ectopic occurrence might be implicated in the impaired spermatogenesis.

Adult↗
PubMed1987

Positron emission tomography in minor ischemic stroke using oxygen-15 steady-state technique.

A study with positron emission tomography (PET) was performed on 10 patients with ischemic stroke and mild disability. The patients underwent cerebral angiography, x-ray computed tomography (CT) scan and regional cerebral measurements of CBF, CMRO2, oxygen extraction ratio (OER), and cerebral blood volume (CBV). Only minor arterial involvement was detected by angiography. In all patients, PET images of functional defects were more extensive than the corresponding CT hypodensity, and there were statistically significant reductions in CBF, CMRO2, and CBF/CBV ratio as compared with control subjects. Half of the regions analyzed in the affected hemisphere demonstrated a disruption of the normal coupling between CBF and CMRO2 as reflected by OER values significantly higher or lower than those of the corresponding region of the contralateral hemisphere. The pathophysiological pattern of high OER combined with a reduction in CBF proportionally greater than the reduction in CMRO2 was particularly indicative of regional chronic hemodynamic compromise in these patients.

Aged↗
PubMed1987

RBE of a thermal neutron beam and the 10B(n, alpha)7Li reaction on cultured B-16 melanoma cells.

The RBE of a thermal neutron beam and the 10B(n, alpha)7Li reaction were determined in cultured B-16 melanoma cells. The Kyoto University Research Reactor (KUR) was used as a thermal neutron source which had a very low contamination of gamma-rays and fast neutrons. The cells were irradiated with the beam in the presence or absence of 10B-boric acid. The absorbed dose from the neutron capture reaction to the cells was calculated by a method of Kitao (1975). Survival curves in both conditions had no shoulder and Do values were 0.506 or 0.604 Gy in the presence or absence of 5 micrograms 10B/ml-medium, respectively. The Do value of the 10B(n, alpha)7Li reaction was also estimated at 0.466 Gy, assuming each component of radiation was additive. The RBEs of the KUR thermal neutron beam and the 10B(n, alpha)7Li reaction relative to 60Co gamma-rays were estimated as 4.62 and 6.01 at 0.1 surviving fraction, respectively. Using these results, we calculated the absorbed dose from the 10B-compound and estimated the specific accumulation in the cultured cells of 10B-compounds which we have previously reported but not quantified (Nakanishi et al. 1980, Ichihashi et al. 1982).

Cell Line↗
PubMed1987

The free ulnar forearm flap.

Many flaps have been described based on the septocutaneous perforators; these have many advantages for the coverage of soft tissue defects. The ulnar forearm flap described by Lovie is a septocutaneous flap based on the septocutaneous perforators of the ulnar artery. We report the use of this flap in 2 patients who required soft tissue coverage. The ulnar forearm flap has the advantages of thin and pliable skin, constant and large pedicle, and the technical possibility of combination with the muscles, sensory or motor nerve, and ulna. Comparing it with the radial forearm flap, there is no possibility of exposure of flexor tendons, which usually results in the good take of skin grafts. After skin grafting, the donor scar is unnoticeable because of its position on the forearm. This flap is for the coverage of thin defects that require mobility, such as in the extremities or the intraoral region. It also could be used for the coverage of hand or arm defects as a distally or proximally based island flap, respectively.

Forearm↗
PubMed1987

Transfer of latissimus dorsi to replace a paralysed anterior deltoid. A new technique using an inverted pedicled graft.

A new method of replacement for the paralysed anterior deltoid is described. The latissimus dorsi with its neurovascular pedicle is freed and rotated, and then placed over the anterior part of the paralysed muscle. The lever arm of the transposed muscle is as long as that of the deltoid, and the muscle volume is enough to restore the natural contour of the shoulder. We report operations on 10 patients with shoulder palsy, eight caused by brachial plexus injury and two by resection of a neurilemmoma of the plexus. In six cases, active flexion to over 90 degrees was achieved. At least one of the rotator cuff muscles or the long head of biceps should have some active function if good results are to be obtained.

Adolescent↗
PubMed1987

Regional cerebral metabolic rate for glucose and cerebrospinal fluid monoamine metabolites in subacute sclerosing panencephalitis.

Regional cerebral metabolic rate for glucose (rCMRglu) and cerebrospinal fluid monoamine metabolites were measured in two cases of subacute sclerosing panencephalitis (SSPE) with different clinical courses. A marked decrease in rCMRglu was found in the cortical gray matter of a patient with rapidly developing SSPE (3.6-4.2 mg/100 g brain tissue/min). However, the rCMRglu was preserved in the caudate and lenticular nuclei of the patient (7.7 mg/100 g/min). The rCMRglu in a patient with slowly developing SSPE revealed patterns and values similar to those of the control. Cerebrospinal fluid monoamine metabolites; homovanilic acid and 5-hydroxyindoleacetic acid, were decreased in both rapidly and slowly developing SSPE. These data indicated that rCMRglu correlated better with the neurological and psychological status and that dopaminergic and serotonergic abnormalities have been implicated in pathophysiology of SSPE.

Adolescent↗
PubMed1987

Reflex responses of neurons in the inferior mesenteric ganglion to mechanical stimulation of the colon, rectum, anal canal, and urinary bladder in the dog.

Unitary discharges were recorded from the inferior mesenteric ganglion of decerebrate dogs. Eighty-one units were identified as sympathetic postganglionic neurons innervating the colon and rectum by collision test performed by stimulation of the lumbar colonic nerve. Discharges of four units were enhanced simultaneously with an increased outflow of the renal nerve by pinching a toe. Thus, those units were regarded as vasoconstrictors of colonic blood vessels. Sixty-five units whose discharges were depressed or not affected by the pinching were regarded as neurons innervating colonic smooth muscle or mucosa (colonic units). Discharges were enhanced in the majority of the colonic units by colonic, rectal, and vesical distension, and mechanical stimulation of the anal canal, while discharges were depressed in a few units by rectal and vesical distension, and the anal canal stimulation. The number and percentage of the depressed units increased not only after cutting the hypogastric nerves and descending branches of the lumbar colonic nerve but also after transection of the caudal pons. The reflex depressions disappeared after transection at the bulbospinal junction, but the reflex enhancements remained. These results indicate that the colonic units are enhanced through a spinal reflex by the inflows from the distal colon, rectum, anal canal, and urinary bladder through the lumbar colonic, hypogastric, pelvic, and pudendal nerves, while a few are inhibited through a supraspinal reflex by inflows through the pelvic and pudendal nerves.

Action Potentials↗
PubMed1987

Comparison of the effects of the new anxiolytic suriclone and benzodiazepines on motor function and electroencephalogram.

(6-(7-Chloro-1,8-naphthyridin-2-yl)-7-oxo-2,3,6,7-tetrahydro-5H- 1,4- dithiino[2,3-c]pyrrol-5-yl)-4-methyl-1-piperazinecarboxylate (suriclone, RP 31264), a new anxiolytic, produced behavioral effects similar to those of diazepam and lorazepam, had a protective effect against electroshock convulsion and potentiated the sleeping effect of hexobarbital in mice. It inhibited crossed extensor reflexes in chicks and augmented the dorsal root reflex potential, the increase of which is considered to be an index of increased GABAergic presynaptic inhibition. Suriclone produced high-amplitude slow waves in the amygdala and cerebral cortex and desynchronization of theta waves in the hippocampus in rat electroencephalogram (EEG). These observations were quantitatively confirmed by power spectrum analysis of EEG. The mechanisms of action of suriclone on the CNS are discussed in relation to those of benzodiazepines.

Animals↗
PubMed1987

[Antitumor effects of 5'-deoxy-5-fluorouridine (5'-DFUR) against various murine tumors in combination with recombinant interferon alpha or cytostatics].

Antitumor effects of oral fluorinated pyrimidines including 5'-DFUR and their combination with recombinant interferon (rIFN) alpha A/D (Bgl) or cytostatics were investigated using various tumor models in mice. 5'-DFUR was more effective against Colon 26 than tegafur and 5-FU as a single agent, and their therapeutic indices were 14.7, 2.3 and 1.2, respectively. In combination with various cytostatics, 5'-DFUR as well as 5-FU and tegafur showed better efficacy against mouse Colon 26, Meth A fibrosarcoma and A755 adenocarcinoma than any other single agents. Combination therapy with 5'-DFUR and rIFN-alpha A/D also showed better efficacy against all seven murine tumors tested than their single therapy. In these combination therapies, increased toxicities measured by a body weight change and the incidence of toxic death were also observed to some extent. Among combinations with fluorinated pyrimidines, those with 5'-DFUR showed the toxicities at a lesser degree than those with 5-FU or tegafur. These results indicate that 5'-DFUR would be useful for the multiple combination chemotherapy like 5-FU and tegafur.

Animals↗