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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 649 records · Page 36Linked to original sources
PubMed1993

Laryngomicrosurgery with carbon dioxide laser for laryngeal papillomatosis: application of a two-stage operation.

Among the many treatments reported, CO2 laser surgery has recently been applied in the field of laryngomicrosurgery to treat laryngeal papilloma. It is exceedingly difficult to cure this disease, however, because of its rapid recurrence following surgery. Incomplete removal of papilloma is believed to be caused by the difficulty of precisely identifying residual papillomas during surgery. In an effort to resolve this problem, we have developed a new surgical method which we call the "two-stage operation," in which a series of two operations are performed about 10 days apart. By the time of the second operation, the bleeding, coagulated blood, and carbonized tissue from the first operation have resolved, and the laryngeal image is much clearer. If additional lesions are found, they are removed at the second operation. We applied this method to several patients with recurrent laryngeal papillomatosis and obtained good results. This new method is clearly useful in the treatment of laryngeal papillomatosis, and it promises to decrease the recurrence rate. In this paper we present the case of a 26-year-old male with laryngeal papilloma who underwent surgery 1 month previously at another hospital. Laryngeal endoscopy revealed multiple papillomas especially of the glottis. The first operation with the CO2 laser was performed on April 16, 1990. Visible lesions appeared to have been completely removed. The second operation was carried out 10 days after the first operation, and the small residual lesions were removed with the CO2 laser. The patient has been disease-free for 18 months.

Adult↗
PubMed1993

Lipogenic enzyme gene expression in rat liver during development after birth.

The time courses and the regulation of lipogenic enzyme gene expression during development after birth have been investigated. The mRNA concentrations and activities of liver lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase, malic enzyme, glucose-6-phosphate dehydrogenase, and ATP-citrate lyase) were very low in all the suckling rats, regardless of dietary fat of the mothers. After weaning to the same diet as the mothers, the mRNA and enzyme levels were greatly increased by the fat-free or hydrogenated fat diet but not so greatly increased by the corn or fish oil diet. The mRNA concentrations of all the groups reached maximum at 4-6 weeks old and then decreased, usually to 40-60% of the maximal levels. It appeared that the gene expression after weaning is subject to strong nutritional regulation, as well as developmental regulation. The plasma levels of triiodothyronine and insulin were low during suckling. Malic enzyme mRNA level was increased by triiodothyronine treatment even during suckling, but the absolute increase was much less than after weaning. Thus, the gene expression of lipogenic enzymes during suckling appeared to be suppressed by nutritional and hormonal regulation, or may not be sufficiently developed. On the other hand, the hepatic triacylglycerol levels were increased slightly at 2 weeks old and greatly at 3 weeks. As the gene expression of lipogenic enzymes was still low at that time, the major triacylglycerols appear to be obtained from milk and accumulated in preparation for weaning.

ATP Citrate (pro-S)-Lyase↗
PubMed1993

GABAA receptor-induced inhibition of neuronal burst firing is weak in rat somatosensory cortex.

Extracellular and intracellular recordings have been made from the somatosensory cortex of anesthetized rats. From 264 neurons having receptive fields including the contralateral whiskers, we have determined that two distinct patterns of firing are observed, and call these two patterns regular spiking and bursting. Iontophoretically administered gamma-aminobutyric acid (GABA), muscimol, or flurazepam showed significantly weaker inhibition of the bursting pattern of firing than of the regular spiking pattern. By contrast, baclofen inhibited both types of firing to the same extent. These results suggest that intracortical GABA receptor subtypes are involved in different ways in modulating the expression modes of discharge.

Animals↗
PubMed1993

NMDA receptors mediate neuronal burst firing in rat somatosensory cortex in vivo.

Two patterns of neuronal firing, bursting and regular spiking, are observed in the somatosensory cortex of anesthetized rats. The effects of excitatory amino acid receptor agonists and antagonists on these discharge types have been examined in vivo, in order to assess their involvement in the generation of such firing patterns. The analysis of interspike interval histograms indicates that N-methyl-D-aspartate (NMDA) receptors are involved in the generation of bursting responses while non-NMDA receptors mediate the regular spiking pattern of firing in individual neurons. It is also suggested that a basal level of ongoing neuronal excitation via the activation of non-NMDA receptors is required for bursting to be evoked through NMDA receptors.

2-Amino-5-phosphonovalerate↗
PubMed1993

Molecular cloning and characterization of cDNAs associated with tracheary element differentiation in cultured Zinnia cells.

Mesophyll cells isolated mechanically from leaves of Zinnia elegans L. cv Canary bird differentiate into tracheary elements (TE) semisynchronously and at high frequency. Using this system, three cDNA clones, TED2 to TED4, whose corresponding mRNAs were expressed in a close association with tracheary element differentiation, were isolated by differential screening of a lambda gt11 cDNA library. The library was prepared using poly(A)+ RNA from cells cultured in a TE-induced medium for 48 h prior to morphological changes, including secondary cell-wall thickenings and autolysis. Northern analysis indicated that mRNAs corresponding to the clones were expressed preferentially in cells differentiating into TEs prior to the morphological changes. The expression of the mRNAs was found not to be induced by alpha-naphthaleneacetic acid or benzyladenine solely and not to be associated directly with cell division. Analysis of the nucleotide sequence of TED4 showed that the cDNA contains an open reading frame of 285 bp, encoding a polypeptide comprising 95 amino acid residues with a predicted molecular mass of 10.0 kD. A homology search of the nucleotide and amino acid sequences of TED4 with several data bases revealed a significant similarity to those of the barley aleurone-specific clone B11E, which was isolated as an aleurone-specific cDNA from 20-d postanthesis grain.

Amino Acid Sequence↗
PubMed1993

Rapid diagnosis of gastric malignant lymphoma from biopsy specimens: detection of immunoglobulin heavy chain rearrangement by polymerase chain reaction.

The endoscopic appearances of the gastrointestinal lymphomas differ widely, and it is often difficult to make the distinction between a benign lymphoproliferative disorder and a malignant lymphoma even with a histologic evaluation. Since almost all primary malignant lymphomas of the gastrointestinal tract are of B-cell origin, the confirmation of monoclonality in immunoglobulin (Ig) is helpful for differential diagnosis. Rearrangements of the Ig heavy chain gene were examined by polymerase chain reaction (PCR) analysis in frozen biopsy specimens of human stomach. The sensitivity of the analysis was sufficient to detect even a 5% clonal B-cell proliferation and results could be obtained within 17 h. In a clinical investigation, seven of eight cases (88%) of primary gastric malignant lymphoma showed a single band in polyacrylamide gel electrophoresis (PAGE) after PCR, suggesting a monoclonal proliferation of B-cell lineage. By contrast, all seven cases of reactive lymphoreticular hyperplasias showed a broad smear pattern in PAGE, which is thought to reflect polyclonal proliferation. None of the lymphocytes infiltrating around gastritis (7 cases), gastric ulcers (12 cases) and gastric carcinomas (15 cases) showed a monoclonal proliferation pattern. These findings suggest that detection of monoclonality in Ig heavy gene rearrangement by PCR is useful for the differential diagnosis of B-cell lymphoproliferative diseases in the gastrointestinal tract.

Base Sequence↗
PubMed1993

Experimental seizure-induced brain damage: electrophysiological, metabolic and pathological correlation.

Limbic seizures elicited by an intra-amygdaloid KA injection is the only and unique model which can produce unilateral hippocampal degenerative lesions and atrophy. This model is important not only to investigate neurophysiological epileptogenesis but also to study the causative process of human mesial temporal sclerosis observed in patients with intractable complex partial seizure.

Amygdala↗
PubMed1993

Audiological study in guinea pigs with type I allergy induced in the inner ear.

Time course studies of electrocochleography and the auditory brain stem response were performed in guinea pigs that were passively sensitized by sera containing antidinitrophenyl reaginic antibody and specifically challenged by dinitrophenyl-bovine serum albumin injected through the stylomastoid foramen. A negative summating potential on electrocochleography was observed from 12 to 48 hours, but not at 72 hours, after the specific challenge. A threshold increase on the auditory brain stem response was observed 15 minutes after the specific challenge; the threshold recovered to the prechallenge level within 7 days. Further, we used Tranilast, a blocking agent of chemical mediator release from mast cells, before the specific challenge. A negative summating potential and head deviation were not observed after the use of this agent. These results suggest that the auditory change provoked in the inner ear of the sensitized guinea pig may have been induced by type I allergy.

Animals↗
PubMed1993

Local cerebral glucose utilization in rats with decerebrate rigidity and effects of centrally acting muscle relaxants, diazepam and tizanidine.

Local cerebral glucose utilization (LCGU) was investigated in rats with decerebrate rigidity using the [14C]2-deoxyglucose (2DG) method in order to identify the site responsible for the rigidity. LCGU was increased in the medial vestibular nucleus, the fastigial nucleus, the interpositus nucleus and the dentate nucleus during decerebrate rigidity. Diazepam and tizanidine, centrally acting muscle relaxants, reduced the increase of LCGU in the vestibular and cerebellar nuclei. These results suggest that the vestibular and cerebellar nuclei are the possible sites responsible for the development of decerebrate rigidity and the action of some centrally acting muscle relaxants.

Animals↗
PubMed1993

Effect of the centrally acting muscle relaxant tizanidine on spinal reflexes: involvement of descending noradrenergic systems.

Experiments were performed on intact and spinalized rats anesthetized with urethane and alpha-chloralose. In intact rats, administration of tizanidine (0.1 mg/kg, i.v.) decreased the mono- (MSR) and polysynaptic reflex potentials (PSR). Blood pressure was initially elevated and then lowered by tizanidine. Although pretreatments with hexamethonium and phentolamine prevented the tizanidine-induced decrease in blood pressure, the depressant effects of tizanidine on the reflexes remained. The alpha 2-antagonist idazoxan inhibited the tizanidine-induced decrease in spinal reflexes, suggesting that central alpha 2-adrenoceptors are involved in the depression of the reflexes. In spinalized rats, tizanidine transiently increased the MSR and gradually decreased the PSR. Blood pressure was elevated transiently by tizanidine. Although the hypertensive effect of tizanidine was inhibited by phentolamine, the effect of tizanidine on the PSR did not change. Prazosin blocked the stimulatory effect of tizanidine on the MSR and caused a rapid decrease of the PSR, suggesting that spinal alpha 1-adrenoceptors are involved in the enhancement of the reflexes. These results suggest that the depressant effects of tizanidine on spinal reflexes are due to the supraspinal and spinal effects of the drug, and not to changes in blood pressure.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1993

Purification and characterization of cytochrome P450 from an isobutene-forming microorganism, Rhodotorula minuta.

A cytochrome P450 was purified from microsomes of Rhodotorula minuta. The optical spectrum of the purified cytochrome was characteristic of a low-spin ferric heme protein. Isovalerate caused a type I spectral change in it. The amino-terminal sequence of the cytochrome was different from those of other known microsomal cytochrome P450s. These results indicate that the cytochrome, which is tentatively named P450rm, is a novel species of cytochrome P450.

Alkenes↗
PubMed1993

Magnetic resonance imaging in kainic acid-induced limbic seizure status in cats.

Magnetic resonance imaging before, during, and after kainic acid (KA)-induced limbic seizure status in cats demonstrated the bilateral hippocampi as slightly high-intensity areas on the T2-weighted images during the limbic seizure status, and isointensity areas 1-2 weeks after KA injection when the limbic seizure status subsided. However, the hippocampi again became high-intense 1-3 months after KA injection. Histological study suggested that the high-intensity area during the limbic seizure status resulted from regional edema, and in the chronic period from marked gliosis and/or atrophic change as a consequence of tissue damage in the hippocampus.

Amygdala↗
PubMed1993

Growth and essential fatty acid levels of plasma and liver of suckling rats from mothers fed on fat-free or various fat diets.

The milk fatty acid compositions of mothers fed on a fat-free or various fat diets, and the effects on growth and fatty acid compositions of their pups were studied. Even the milk of essential fatty acid-deficient mothers fed on a fat-free or hydrogenated fat diet contained about 3 and 1.7%, n-6 and n-3 fatty acids, respectively. In the plasma of the suckling pups, however, the proportions of n-6 and n-3 fatty acids rapidly increased to about 20 and 3-5%, respectively, at 1 week after birth. In particular, the PUFAs markedly increased in the liver PC and PE, and the high levels were maintained until weaning. Although the PUFA compositions of suckling pups were influenced with those of maternal diet, small amounts of n-6 and n-3 fatty acids were usually maintained in the plasma and liver. After weaning to the same diets (without PUFAs) as the mothers, however, the n-3 and n-6 fatty acids rapidly decreased and endogenous n-9 eicosatrienoic acid appeared. On the other hand, the growth during suckling was not significantly different among the litters of mothers fed on diets with or without n-3 or n-6 fatty acids. After the weaning, however, the growth was improved in the following order: corn oil, perilla oil > fish oil > fat-free, hydrogenated fat diet group. n-3 fatty acids appeared to be used partially as substitutes for n-6. However, the essentiality was not clear, as the n-3 fatty acids always coexisted with the n-6. Thus, it appeared that small amounts of n-3 and n-6 fatty acids in milk were supplied to the suckling animals regardless of maternal diet and supported growth.

Animals↗
PubMed1993

[A role of dentists in the management of HIV-infected persons].

Oral manifestations of HIV infection include hairy leukoplakia, Sjögren's syndrome-like conditions, necrotizing stomatitis, Kaposi's sarcoma, and a variety of opportunistic viral or mycotic infections. The well awareness of HIV-associated oral lesions can contribute to the early detection and diagnosis of HIV infection. Prevention and early treatment of common oral diseases including dental caries and periodontal disease, which may evolve into necrotizing gingivitis and stomatitis under immunodeficiency, is required to maintain quality of life and to improve prognosis of persons with AIDS. It is to be desired that many dentists take part in teams of the management of HIV-carrier. Another major issue is protection from HIV infection during dental treatment procedures. It is thought now that there is little probability of transmitting HIV infection during dental treatment. Current fears regarding virus-borne disease including hepatitis-B and AIDS have prompted changes in dentistry's approach to infection control. Fear, ignorance and uncertainty, however, produce irrational behavior of dental staffs and persons without HIV infection toward patients with HIV infection. It is expected that the general public as well as dental staffs has a satisfactory knowledge about HIV infection.

Dental Staff↗