Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 289 records · Page 16Linked to original sources

PubMed1999

Usefulness of fluorescence photography for diagnosis of oral cancer.

This study was carried out to evaluate the validity of fluorescence photography as an adjunctive diagnostic method for oral cancer. Fluorescence photography was performed on 130 oral lesions in 130 patients. Lesions showing red, orange or pink fluorescence on the photographs were defined as positive, while all other lesions were considered negative. Seventy-two (91.1%) of 79 carcinomas and 6 (85.7%) of 7 epithelial dysplasias were judged as positive, whereas two (4.5%) of 44 benign lesions that were not dysplasias showed positive fluorescence. Sixty-nine (94.5%) of 73 squamous cell carcinomas showed positive fluorescence. These results suggest that fluorescence photography is useful as an adjunctive diagnostic method for oral squamous cell carcinoma.

Adult↗

PubMed1999

[Current issues and perspectives in Japan Clinical Oncology Group].

Clinical trials can be classified either as "sponsored trials (sponsored by industries)" or "non-sponsored trials (funded by government etc.)". The former is for the application of the commercialization/import of new drugs by the government, and the latter basically seeks to establish and improve the "State of the Art" of medical treatments/prevention in certain disease fields. We present an overview of the Japan Clinical Oncology Group (JCOG), which is a cooperative group funded by government for conducting non-sponsored cancer clinical trials, and the fundamental procedures managed by our JCOG Data Center. The problems and difficulties concerning data management in our trials, our roles and limitations as a non-commercial data coordinating center, future perspectives and issues on local data management are also discussed.

Clinical Protocols↗

PubMed1998

Non-N-methyl-D-aspartate receptors may mediate the transmission of emetic signals between visceral vagal afferents and the solitary nucleus in dogs.

The effects of the N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists MK-801 and NBQX, respectively, on salivary secretion and retching induced by vagal stimulation were studied in decerebrate dogs. Vagal stimulation induced an increase in salivary secretion and fictive retching. Intra-4th ventricular application of vehicle or MK-801 did not change either response, while NBQX completely abolished both responses. These results suggest that non-NMDA receptors mediate both responses in the solitary nucleus.

Anesthesia↗

PubMed1998

Characteristics of mutations in the p53 gene of oral squamous-cell carcinomas associated with betel-quid chewing in Sri Lanka.

Oral squamous-cell carcinoma (SCC) is the most common neoplasm in Sri Lanka, accounting for approximately 30% of all cancers in males. Epidemiologic evidence indicates that there is an unequivocal relationship between betel chewing and oral carcinogenesis, suggesting that there may be specific genetic targets of betel-quid ingredients. The p53 gene has been indicated to be a tumor-suppressor gene that is found in mutated form in common human cancers; however, there are few reports about "carcinogen-specific" p53 mutation. Because of this background, primary resected specimens from 23 oral SCCs, 7 leukoplakias and 2 oral submucous fibrosis were collected from oral SCC patients in Sri Lanka and were used for p53 mutation analysis. Exons 5 through 8 of the p53 gene were examined by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct sequencing. Mutations in the p53 gene were frequent (10/23) in oral SCC specimens from Sri Lanka. Moreover, the mutations clustered significantly in exon 5 (7/10) of the p53 gene, and small deletions and inclusions other than point mutations were observed. These results indicate that 1) betel-quid chewing may cause specific genetic changes, including mutation in the p53 gene; 2) mutations in the p53 gene are not rare events in SCC patients who are betel-quid chewers, which contrasts with other reports; 3) exon 5 of the p53 gene could be one of the specific targets for some betel-quid ingredients; and 4) betel-quid chewing may be a critical environmental factor in the development of oral SCC.

Adult↗

PubMed1998

Participation of the prefrontal cortices in prospective memory: evidence from a PET study in humans.

Prospective memory is a memory feature in humans which involves activities for remembering to do something in the future. The present study provides functional neuroanatomy of prospective memory for the first time. We used positron emission tomography (PET) and found several localized brain activations in relation to a prospective memory task required to retain and remember a planned action while performing an ongoing routine activity. Activations were identified in the right dorsolateral and ventrolateral prefrontal cortices, the left frontal pole and anterior cingulate gyrus, the left parahippocampal gyrus, and midline medial frontal lobe. We attributed these activations to several cognitive processes involved in prospective memory, such as holding an intention toward future behavior, checking target items within presented stimuli, and dividing attention between the planned action and the routine activity.

Adult↗

PubMed1998

The tachykinin NK1 receptor antagonist GR205171 prevents vagal stimulation-induced retching but not neuronal transmission from emetic vagal afferents to solitary nucleus neurons in dogs.

Tachykinin NK1 receptor antagonists injected into the medulla oblongata are known to abolish vomiting induced by vagal afferent stimulation. Emetic vagal afferents have been shown to synapse with neurons in the medial solitary nucleus (mNTS), which suggests that substance P is a transmitter in the synapse. To examine this possibility, the effects of GR205171, an NK1 receptor antagonist, on retching and mNTS neuronal responses to the stimulation of abdominal vagal afferents were investigated in decerebrate dogs. GR205171 (0.05-0.7 mg kg-1, i.v.) abolished retching induced by either vagal or mNTS stimulation within 5 min. Firing of mNTS neurons in response to pulse-train and sustained vagal stimulation did not change even after the abolition of retching. Similarly, GR205171 did not have any effects on mNTS evoked potentials induced by pulse-train vagal stimulation. In about 20% of mNTS neurons, the peak firing frequency was facilitated to about 150% with repetitive pulse-train vagal stimulation. This facilitation remained even after the abolition of retching. Administration of GR205171 (1 mg ml-1, 30 microliters) into the 4th ventricle abolished retching, with latencies in excess of 120 min These results suggest that substance P does not participate in synaptic transmission between emetic vagal afferents and mNTS neurons in dogs.

Animals↗

PubMed1998

Factors affecting mandibular complications in low dose rate brachytherapy for oral tongue carcinoma with special reference to spacer.

PURPOSE: To evaluate the efficacy of a spacer in the prevention of mandibular complications in low dose rate (LDR) brachytherapy (BRT) for oral tongue carcinoma. METHODS AND MATERIALS: A retrospective analysis was conducted using 103 patients with T1 or T2 tongue carcinoma treated by a single plane implantation of iridium (192Ir) pins between 1979-1994. Of these patients, 60 were treated by BRT alone, and the rest were combined with external irradiation (Ext) and/or chemotherapy (CHT). Forty-eight and 55 patients were given BRT with and without a spacer, respectively. Spacers were individually made of acrylic resin according to a prosthetic technique so as to obtain the thickness of 7-10 mm at the lingual part of the implanted side. Variables, including a spacer, which may be associated with the development of osteoradionecrosis (ORN) of the mandible, were analyzed by the Cox proportional hazards regression analysis. RESULTS: Our spacer reduced about 50% of the absorbed dose at the lingual side surface of the lower gingiva (LSG) to that in the absence of a spacer. Absolute incidence of ORN was 2.1% (1 of 48) and 40.0% (22 of 55), with and without a spacer, respectively, and the difference was statistically significant by univariate analysis (p = 0.0004). It was revealed by the Cox analysis that the spacer (p = 0.0247), combined CHT (p = 0.0295), and combined Ext (p = 0.0279) were significant independent factors associated with the development of ORN. The spacer was shown to be a significant factor by univariate analysis (p = 0.0037), but not by multivariate analysis when analysis was restricted to the patients who did not receive CHT. The absorbed dose, dose rate, and biological effective dose (BED) reflecting early or late response were estimated at the LSG, and prognosticators associated with the incidence of ORN were also determined by the Cox analysis. Particularly, BED for late response by BRT, the total absorbed dose, and any BED by Ext plus BRT were highly significant factors in the whole population. Essentially similar results were obtained in the patients without receiving CHT. CONCLUSIONS: It was clarified that our spacer effectively prevents mandibular complications in LDR BRT by 192Ir for oral tongue carcinoma. Furthermore, introduction of a spacer provided novel information concerning the development of ORN, where BED particularly for late response given by BRT, the total absorbed dose, and any BED by Ext plus BRT could be good prognostic factors only when estimated at the LSG.

Adult↗

PubMed1998

BEN1 and ZEN1 cDNAs encoding S1-type DNases that are associated with programmed cell death in plants.

We describe the isolation and characterization of cDNAs encoding two DNases that may be involved in the programmed death of plant cells: a 35-kDa nuclease of barley, which had been reported to be secreted from the aleurone layer into the endosperm during germination and may be responsible for the digestion of nuclear DNA in the course of degradation (cell death) of endosperm, and a 43-kDa nuclease of zinnia, which appears transiently in association with differentiation to tracheary elements and is likely to participate in the autolysis at the final step of the differentiation. Genes for these nucleases of barley and zinnia were designated BEN1 and ZEN1, respectively. The amino acid sequence of BEN1 protein deduced from the nucleotide sequence of BEN1 cDNA consisted of 288 residues with a putative signal sequence of 23 residues. RNA gel blot analysis revealed that BEN1 mRNA increased in the embryo-less half seeds of barley in response to the application of gibberellic acid. The deduced amino acid sequence of ZEN1 protein consisted of 303 residues with a putative signal sequence of 25 residues. Temporal accumulation of ZEN1 mRNA was detected during transdifferentiation of zinnia mesophyll cells into tracheary elements. Significant similarities were found among the amino acid sequences of BEN1, ZEN1, nuclease S1 from Aspergillus oryzae, and two other S1-type nucleases.

Amino Acid Sequence↗

PubMed1998

The role of the left inferior temporal cortex for visual pattern discrimination--a PET study.

We measured regional cerebral blood flow using positron emission tomography in seven normal volunteers during discrimination tasks for visual patterns. For the 'attention to right or left' tasks, the subjects were instructed to press a key when sample and test stimuli presented in the right or left visual fields, respectively, were identical. In the control task, subjects were instructed to press a key on every second presentation of the test stimulus. Both discrimination tasks activated the same area in the inferior temporal sulcus of the left hemisphere. The results indicate that the left inferior temporal cortex plays a dominant role in the discrimination of visual pattern in right handed subjects.

Adult↗

PubMed1998

Neuroanatomical correlates of the assessment of facial attractiveness.

Frontal cortical damage can lead to changes in affective aspects of personality. However, the difficulty of dissociating such abnormalities from cognitive disorders has overshadowed most previous findings. Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET) while normal subjects were assessing facial attractiveness. Two left frontal regions showed a significant increase in rCBF while assessing facial attractiveness. The increased rCBF in the left anterior frontal cortex correlated with the overall percentage of assessments of a face as unattractive, while that in the left fronto-temporal junction correlated with the percentage of assessments of a face as attractive. These findings provide direct evidence that the left frontal regions are engaged in the assessment of facial attractiveness.

Adult↗

PubMed1998

Immunophenotypic studies on atypical lymphocytes in psychiatric patients.

By using phase-contrast microscopy combined with a fluorescent staining technique, the frequency of blast-type atypical lymphocytes (BTALs) appearing in peripheral blood and the phenotypic expression of their surface antigens were studied in 24 patients with schizophrenia, 16 with mood disorder and 14 healthy controls. BTALs were classified as being stimulated or activated cells, morphologically characterized by their large size, dark cytoplasm, a hollow perinuclear containing a few granules and finely dispersed chromatin structures with a few evident nucleoli. A significantly higher number of BTALs were found in the schizophrenic patients compared with healthy control subjects or patients with mood disorder. Further, there was a significant difference in the frequency of BTALs between patients with mood disorder and healthy control subjects. No significant difference in the frequency of BTALs was found between the schizophrenic patients with and without medication. Immunostaining of BTALs revealed that these cells consisted of B, T and non-B, non-T cell subpopulations. Contrary to our expectations, the T cell was only one third of the BTAL population. HLA-DR and CD38 were expressed on most BTALs (> 70%), while CD25, an early activation marker of T cells was rarely found on BTALs (< 0.3%). The differences in activated lymphocyte populations which appeared as morphologically atypical in the circulation among some psychiatric patients and infectious or autoimmune diseases are discussed. This is the first report on populations of BTALs.

Acute Disease↗

PubMed1998

Lung as reservoir for antidepressants in pharmacokinetic drug interactions.

BACKGROUND: Although high-affinity imipramine binding sites have been reported in both rat and human lung, the role of the lungs in the pharmacokinetics of antidepressants has not received much attention. Substantial accumulation of selective serotonin-reuptake inhibitors (SSRIs) in the lungs has been reported. We have investigated the role of the lungs in pharmacokinetic drug interactions between tricyclic antidepressants and SSRIs. METHODS: We used a carbon-11-labelled form of the imipramine derivative cyanoimipramine to measure uptake in the lungs and brain of healthy volunteers by positron emission tomography. Clomipramine (50 mg) was administered to measure the effect of antidepressants with high affinity for the serotonin transporter on lung and brain uptake. FINDINGS: A large proportion of the injected 11C-cyanoimipramine (68-86% in the four volunteers) was extracted by the lungs. Clomipramine decreased the lung uptake from 68% to 35% and from 81% to 54% in the two volunteers studied. By contrast, whole-brain uptake was low in control studies (1.7-2.0% in three volunteers) and increased after clomipramine administration (to 4.5-4.9%). Plasma radioactivity was also higher after clomipramine than in control studies. INTERPRETATION: The lungs may function as a reservoir for antidepressants with high affinity to the serotonin transporter. The accumulated antidepressants may be displaced by other antidepressants, and this displacement would substantially increase plasma concentrations and thus cause toxic effects.

Adult↗

PubMed1998

A PET study of axis orientation discrimination.

We examined the cortical areas showing increased activation related to axis orientation discrimination in hand movement and perception by positron emission tomography (PET) in right-handed normal human subjects while they performed a hand orientation (HO) task and an orientation discrimination (OD) task. In the OD task, fields in the parietal cortex and a field in the inferior frontal gyrus showed increased activation relative to the control task. In the HO task, fields in the intraparietal sulcus, the inferior and middle frontal gyri, the fusiform gyrus and the middle temporal gyrus showed increased activation relative to the control task. The results indicate that areas involved in axis orientation discrimination seemed to be segregated in the parietal cortex, with one field in the left intraparietal sulcus related to hand movement and another field in the right intraparietal sulcus related to perception.

Adult↗

PubMed1998

Increased substance P in subacromial bursa and shoulder pain in rotator cuff diseases.

The subacromial bursa is recognized as a site associated with the shoulder pain caused by rotator cuff disease in the middle-aged and elderly. Substance P is contained in primary afferent nerves, and its quantity increases during chronic pain. The amount of substance P in the subacromial bursa of patients with rotator cuff disease was examined. Radioimmunoassay and immunohistochemistry were employed to quantify and localize substance P. The preoperative pain level was measured with a visual analogue scale with 0 as no pain, 5 as moderate, and 10 as severe. Thirty-seven patients that had undergone operation were divided into two groups: one composed of 19 patients with subacromial bursitis and a partial-thickness tear of the rotator cuff (nonperforated cuff) and the other composed of 18 patients with a full-thickness tear (perforated cuff). Subacromial bursae obtained from seven fresh cadavers with no shoulder pain before death were used as controls. The visual analogue scale showed significantly greater pain in the group with the nonperforated rotator cuff than in the group with the perforated cuff. Consistent with these results, the amount of substance P in the subacromial bursa was significantly greater in the former group than in the latter. Nerve fibers immunoreactive to substance P were localized around the vessels, with a larger number of fibers in the group with the nonperforated rotator cuff. Therefore, an increased amount of substance P in the subacromial bursa appears to correlate with the pain caused by rotator cuff disease.

Adult↗

PubMed1998

Use of automated image registration to generate mean brain SPECT image of Alzheimer's patients.

UNLABELLED: The purpose of this study was to compute and compare the group mean HMPAO brain SPECT images of patients with senile dementia of Alzheimer's type (SDAT) and age matched control subjects after transformation of the individual images to a standard size and shape. METHODS: Ten patients with Alzheimer's disease (age 71.6 +/- 5.0 yr) and ten age matched normal subjects (age 71.0 +/- 6.1 yr) participated in this study. Tc-99m HMPAO brain SPECT and X-ray CT scans were acquired for each subject. SPECT images were normalized to an average activity of 100 counts/pixel. Individual brain images were transformed to a standard size and shape with the help of Automated Image Registration (AIR). Realigned brain SPECT images of both groups were used to generate mean and standard deviation images by arithmetic operations on voxel based numerical values. Mean images of both groups were compared by applying the unpaired t-test on a voxel by voxel basis to generate three dimensional T-maps. X-ray CT images of individual subjects were evaluated by means of a computer program for brain atrophy. RESULTS: A significant decrease in relative radioisotope (RI) uptake was present in the bilateral superior and inferior parietal lobules (p < 0.05), bilateral inferior temporal gyri, and the bilateral superior and middle frontal gyri (p < 0.001). The mean brain atrophy indices for patients and normal subjects were 0.853 +/- 0.042 and 0.933 +/- 0.017 respectively, the difference being statistically significant (p < 0.001). CONCLUSION: The use of a brain image standardization procedure increases the accuracy of voxel based group comparisons. Thus, intersubject averaging enhances the capacity for detection of abnormalities in functional brain images by minimizing the influence of individual variation.

Aged↗

PubMed1998

A comparison of Tc-99m HMPAO brain SPECT images of young and aged normal individuals.

The purpose of this study was to examine the normal distribution patterns of 99mTc-HMPAO (HMPAO) in young and aged normal individuals and to clarify differences between the distribution patterns of the two groups by means of an anatomical standardization technique. The tracer distribution was measured with HMPAO and SPECT in 18 normal subjects; age range 20-81 yrs. SPECT images were globally normalized by averaging whole brain radioactivity counts to 100 counts/voxel. The SPECT images for each subject were transformed into the standard brain anatomy by means of a computerized brain atlas, together with each subject's CT images. Mean and SD images for young (28.8 +/- 6.4 yrs) and aged groups (62.3 +/- 10.2 yrs) were then calculated on a voxel-by-voxel basis. Statistically significant differences between young and aged groups were observed in the relative tracer distribution patterns. In the aged group, relative decreases were found in the cortical areas of the frontal and temporal lobes, limbic areas and basal ganglia regions. The results, as visualized changes in tracer distribution patterns with aging, may contribute to more accurate clinical diagnosis.

Adult↗

PubMed1998

The central pattern generator for vomiting may exist in the reticular area dorsomedial to the retrofacial nucleus in dogs.

There is some controversy over whether or not a discrete site that integrates vomiting activities in somatic and autonomic nerves is present in the medulla oblongata. On the basis of our previous studies, we hypothesized that the temporal patterns of muscle contractions in vomiting are generated by a central pattern generator in the retrofacial area of the rostral medulla. To investigate this hypothesis further, the effects of electrical and chemical lesions of the medullary area were observed in decerebrate paralyzed dogs. Efferent activities of the phrenic and abdominal muscle nerves were recorded to recognize fictive vomiting. The right half of the medulla oblongata was transversely severed about 3 mm rostral to the obex. Fictive vomiting responses to vagal stimulation still appeared after hemisection in all 11 dogs. In addition, stimulation of the contralateral reticular area dorsomedial to the retrofacial nucleus produced fictive vomiting even after hemisection. An electrical lesion or injection of kainic acid (0.5-1.0 microl) was applied at the point where reticular stimulation induced fictive vomiting. After this destruction, no activities that corresponded to fictive vomiting could be induced by stimulation of vagal afferents or the reticular site. Salivation was decreased by hemisection, and decreased further, but was not completely abolished, with destruction of the reticular area. Kainic acid is known to selectively destroy neural cell bodies. Therefore, we concluded that neuronal somata in the reticular formation dorsomedial to the retrofacial nucleus play an essential role in the central patterning of vomiting activities in peripheral motor nerves.

Animals↗

PubMed1998

Localizing the site of magnetic brain stimulation by functional MRI.

In order to locate the site of action of transcranial magnetic stimulation (TMS) within the human motor cortices, we investigated how the optimal positions for evoking motor responses over the scalp corresponded to the hand and leg primary-motor areas. TMS was delivered with a figure-8 shaped coil over each point of a grid system constructed on the skull surface, each separated by 1 cm, to find the optimal site for obtaining motor-evoked potentials (MEPs) in the contralateral first dorsal interosseous (FDI) and tibialis anterior (TA) muscles. Magnetic resonance imaging scans of the brain were taken for each subject with markers placed over these sites, the positions of which were projected onto the cortical region just beneath. On the other hand, cortical areas where blood flow increased during finger tapping or leg movements were identified on functional magnetic resonance images (fMRI), which should include the hand and leg primary-motor areas. The optimal location for eliciting MEPs in FDI, regardless of their latency, lay just above the bank of the precentral gyrus, which coincided with the activated region during finger tapping in fMRI studies. The direction of induced current preferentially eliciting MEPs with the shortest latency in each subject was nearly perpendicular to the course of the precentral gyrus at this position. The optimal site for evoking motor responses in TA was also located just above the activated area during leg movements identified within the anterior portion of the paracentral lobule. The results suggest that, for magnetic stimulation, activation occurs in the primary hand and leg motor area (Brodmann area 4), which is closest in distance to the optimal scalp position for evoking motor responses.

Brain Mapping↗