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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 955 records · Page 53Linked to original sources
PubMed1987

Positron tomography for ophthalmology.

Positron emission tomography (PET) has been applied so far to estimate the viability of malignant tumors or to assess cerebral higher function in living animals and in man. Our preliminary results suggested possibilities of nontraumatic imaging diagnosis of orbital tumors; the rate of incorporation of glucose analogue, 18F-2-fluorodeoxyglucose, seemed to reflect the malignant nature of the tissue. PET also gives information concerning regional blood flow, glucose metabolism and oxygen consumption in the brain. We demonstrated chronic cerebral ischemia in cases with rubeosis iridis. PET was more sensitive in detecting lesions responsible for cortical hemianopsia than X-ray computed tomography (CT) and magnetic resonance CT.

Aged↗
PubMed1987

[Fourteen cases of mucosal melanomas of the oral cavity].

Fourteen cases of mucosal melanomas of the oral cavity were treated from January, 1970 to April, 1986 in our department. The patients were 10 males and 4 females and in their fifth and sixth decades with the primary sites in the upper gingiva and palates in the majority. The 3 and 5 year survival rates were 21.4% and 14.3% respectively, with unfavorable prognosis in comparison with cutaneous melanoma. The clinical stages were as follows: stage Ia (1), Ib (8), II (5), which affected the prognosis. The depth of invasion, as described by Breslow et al., were beyond 1.50 mm except in one case, which might be a significant prognostic factor in the study of mucosal melanoma of the oral cavity. Seventy one percent had neck node metastases and 35% had distant metastases. The high occurrence of metastases might be related to their poor prognosis.

Adult↗
PubMed1987

Simultaneous evaluation of drug effects on both the spinal cord and the descending pathways in rats.

Effects of drugs affecting the central nervous system on the spinal reflexes and the descending modulations of the reflexes were simultaneously evaluated in rats. Mono- and polysynaptic reflexes were, respectively, increased and decreased by conditioning stimulation of the nucleus raphe in the medulla, with a deflection in resting dorsal root potential being evoked by the stimulation. Baclofen exclusively depressed the segmental responses without affecting the descending modulatory systems. On the other hand, KW-6629 (7-chloro-N,N,3-trimethylbenzo[b]furan-2-carboxamide) significantly depressed the descending modulations without affecting the segmental responses which were sensitive to baclofen. Diazepam and suriclone reduced the descending influence without affecting the ventral root reflexes. Tolperisone and chlorphenesin carbamate as well as tizanidine depressed not only the segmental reflexes but also the descending modulations. Thus, sites of drug actions were estimated.

Animals↗
PubMed1987

Incomplete thickness rotator cuff tears diagnosed by subacromial bursography.

Incomplete thickness rotator cuff tears (ITRCT) adjacent to the bursal sac were diagnosed preoperatively by subacromial bursography and confirmed by surgical exposure. There were five men and one woman with an average age of 41.8 years. The preoperative duration of shoulder pain ranged from four to 36 months (average, 15.8 months). Clinical manifestations included crepitus and a painful arc in five of the six cases. Glenohumeral arthrography was normal in all cases. Subacromial bursography, subsequently performed, revealed pooling of the contrast medium in a torn area of the bursal side of the rotator cuff in all cases. Surgical treatment was recommended after the failure of conservative treatment for three to ten months. The surgical treatment consisted of both anterior acromioplasty and tendon suture. Wedge resection and shoelace suture repair of the tendon produced satisfactory results in all cases followed for ten to 72 months (average, 44.3 months). ITRCT adherent to the bursal sac were noted in 2.4% of a cadaver survey. Subacromial bursography can be a useful diagnostic procedure for this specific entity in subacromial impingement syndrome.

Adult↗
PubMed1986

Age-related change in serotonin-mediated prejunctional inhibition of rat vas deferens.

The effect of age on the serotonin (5-HT)-induced prejunctional inhibition of twitch contractions induced in rat vas deferens by single-pulse field stimulation at 0.1 Hz was studied. The inhibitory effect of 5-HT gradually decreased with increasing age of the rats (4-15 weeks old) and was no longer detectable in preparations from rats over 15 weeks old. Moreover, on a further increase in age to 45 weeks, 5-HT conversely enhanced the twitch response of the vas deferens. The 5-HT2 antagonists ketanserin and mianserin potentiated the 5-HT-induced inhibition of contractions of the vas deferens of young rats (8-15 weeks old), and attenuated the amplifying effect of 5-HT on the responses of preparations from old rats (95 weeks old). Thus unmasking of the inhibition depended on the age of rats. This change occurred earlier in life in the prostatic portion of the vas deferens than in the epididymal portion. A functional decrease in 5-HT-mediated prejunctional inhibition and the resultant increase in amplification of the twitch response by 5-HT are probably responsible for the age-related decrease in prejunctional inhibition.

Adenosine Triphosphate↗
PubMed1986

The actions of ivermectin on cultured chick spinal cord neurons.

The effects of ivermectin (IVM) on cultured chick spinal neurons sensitive to GABA agonists were investigated. IVM caused a change of membrane potential which was associated with an increase in membrane conductance, apparently reversed at about -40 mV and weakened by repetitive application. Furthermore, this agent did not have any effects on either the actions of GABA agonists on neurons or [3H]GABA efflux from those cells. These results suggest that IVM increases membrane conductance through sites which are different from GABA recognition sites.

Animals↗
PubMed1986

Effects of dietary nutrients on substrate and effector levels of lipogenic enzymes, and lipogenesis from tritiated water in rat liver.

When fasted rats were refed for 4 days with a carbohydrate and protein diet, a carbohydrate diet (without protein) or a protein diet (without carbohydrate), the effects of dietary nutrients on the fatty acid synthesis from injected tritiated water, the substrate and effector levels of lipogenic enzymes and the enzyme activities were compared in the livers. In the carbohydrate diet group, although acetyl-CoA carboxylase was much induced and citrate was much increased, the activity of acetyl-CoA carboxylase extracted with phosphatase inhibitor and activated with 0.5 mM citrate was low in comparison to the carbohydrate and protein diet group. The physiological activity of acetyl-CoA carboxylase seems to be low. In the protein diet group, the concentrations of glucose 6-phosphate, acetyl-CoA and malonyl-CoA were markedly higher than in the carbohydrate and protein group, whereas the concentrations of oxaloacetate and citrate were lower. The levels of hepatic cAMP and plasma glucagon were high. The activities of acetyl-CoA carboxylase and also fatty acid synthetase were low in the protein group. By feeding fat, the citrate level was not decreased as much as the lipogenic enzyme inductions. Comparing the substrate and effector levels with the Km and Ka values, the activities of acetyl-CoA carboxylase and fatty acid synthetase could be limited by the levels. The fatty acid synthesis from tritiated water corresponded more closely to the acetyl-CoA carboxylase activity (activated 0.5 mM citrate) than to other lipogenic enzyme activities. On the other hand, neither the activities of glucose-6-phosphate dehydrogenase and malic enzyme (even though markedly lowered by diet) nor the levels of their substrates appeared to limit fatty acid synthesis of any of the dietary groups. Thus, it is suggested that under the dietary nutrient manipulation, acetyl-CoA carboxylase activity would be the first candidate of the rate-limiting factor for fatty acid synthesis with the regulations of the enzyme quantity, the substrate and effector levels and the enzyme modification.

Acetyl Coenzyme A↗
PubMed1986

Postural change and straining induced by distension of the rectum, vagina and urinary bladder of decerebrate dogs.

In decerebrate dogs, stimulation of pelvic afferent fibres and distension of the rectum, vagina and urinary bladder brought about a sustained postural change and rhythmic abdominal compression. The posture, which resulted from flexion of the back and stifle joints, extension of the hip joints and lifting of the tail, was rhythmically intensified with the abdominal compression. The sustained and rhythmic postural changes are similar to those observed in conscious dogs during defaecation. Intratracheal pressure increased with the abdominal compression. Nervous outflow to the muscles of the glottis, diaphragm, abdominal wall, tail and rear legs changed as would be expected from both the postural changes and the increases in intratracheal and intra-abdominal pressure. Nervous outflow to the external sphincter muscles of the anus and urethra increased simultaneously with both kinds of postural change; however, the increased outflow to the anus was suppressed when defaecation was initiated, and the outflow to the urethra was suppressed when micturition was initiated. In about one-third of the dogs, decreases in the outflow of the pelvic rectal branch and slight increases in the outflow of the vesical branch occurred synchronously with the abdominal compression. These results show that postural change and straining for defaecation, micturition and parturition are reflexly organized by the lower brainstem and the spinal cord.

Action Potentials↗
PubMed1986

Location of the reflex centre for straining elicited by activation of pelvic afferent fibres of decerebrate dogs.

The reflex centres for straining for defaecation, micturition and presumably for parturition were located electrophysiologically in decerebrate dogs. Stimulation of pelvic afferent fibres initially induced a sustained increase in nervous outflow to the diaphragm, rectus abdominis and lateral cricoarytenoid muscles and subsequently induced rhythmic increases which were superimposed on the sustained increase. The rhythmic increases occurred even after transection at the most rostral pons, but they were abolished by a partial cut at the most lateral part of the rostral pons following transection of the contralateral half of the rostral medulla oblongata. The sustained increase continued after transection 1.5 mm caudal to the obex, but disappeared after transection about 5 mm caudal to the obex. This result shows that straining is brought about by both sustained and rhythmic straining reflexes. Both sustained and rhythmic straining, but not defaecation and micturition, could be elicited by stimulation of an area of the Kölliker-Fuse nucleus. The discharges of about half of the units in the nucleus and the neighbouring rostrolateral pontine area which responded to stimulation of the pelvic afferent fibres changed synchronously with the rhythmic straining. These results show that the rhythmic and sustained straining reflex centres are located in the Kölliker-Fuse nucleus and in the lower medulla oblongata, respectively.

Animals↗
PubMed1986

Effects of dietary nutrients on lipogenic enzyme and mRNA activities in rat liver during induction.

By feeding a carbohydrate diet (without protein) to fasted rats, malic enzyme mRNA activity in the liver was increased to the level in rats fed a carbohydrate and protein diet, whereas the enzyme activity itself was increased to 60% of that level. It appears that malic enzyme mRNA activity was increased by dietary carbohydrate, while dietary protein contributed to an increase in the translation of mRNA. In the animals fed carbohydrate without protein, glucose-6-phosphate dehydrogenase mRNA activity increased to 50% of the level in rats fed the carbohydrate and protein diet, whereas the enzyme activity increased to only 25%. By feeding a protein diet (without carbohydrate), glucose-6-phosphate dehydrogenase activity increased to 65% of the level in rats fed both carbohydrate and protein. This enzyme induction appears to be more dependent on protein than carbohydrate. With the carbohydrate diet, acetyl-CoA carboxylase was induced up to the level in the carbohydrate and protein diet group, whereas fatty acid synthetase was induced to only 33%. Acetyl-CoA carboxylase induction appears to be carbohydrate dependent. On the other hand, isotopic leucine incorporation studies showed that the magnitudes of the enzyme inductions caused by the dietary nutrients should be ascribed to the enzyme synthesis rates rather than the degradation. By fat feeding, the mRNA activities of malic enzyme and glucose-6-phosphate dehydrogenase were markedly decreased along with the enzyme induction. Fat appears to reduce these enzyme inductions before the translation of mRNA.

Acetyl-CoA Carboxylase↗