Search PubMed⌕ Search

Biomedical subjects

K Sugaya

Publications and source records attributed to K Sugaya.

At least 127 records · Page 7Linked to original sources
PubMed1990

Nicotinic acetylcholine receptor subtypes in human frontal cortex: changes in Alzheimer's disease.

Molecular genetic and pharmacological studies have suggested that several subtypes of nicotinic acetylcholine receptors exist in the mammalian and avian brain. Combining 3H-(-)-nicotine, 125I-alpha-bungarotoxin, and 125I-kappa-bungarotoxin as ligands, we report here the first evidence for the existence in human frontal cortex of at least three different subtypes of nicotinic receptors. Autoradiographic analysis shows that specific 125I-kappa-bungarotoxin binding sites are concentrated mainly in several cortical layers. We also show that kappa-bungarotoxin, but not alpha-bungarotoxin decreases the evoked release of 3H-acetylcholine in rat cortical slices, indicating a likely presynaptic localization for some of the alpha-bungarotoxin-insensitive kappa-bungarotoxin sites in mammalian brain. The brains of patients with Alzheimer's disease show marked decreases in Bmax values for low-affinity 125I-kappa-bungarotoxin sites and both high- and low-affinity 3H-nicotine sites, whereas 125I-alpha-bungarotoxin sites are not significantly different in number from age-matched control brains. We conclude that Alzheimer's disease does not affect all subtypes of nicotinic receptors in the frontal cortex to the same extent.

Acetylcholine↗
PubMed1990

Production of antikeratin autoantibodies by hybrid spleen cells of naive mice.

The mechanism of the occurrence of natural antikeratin antibodies in human sera was studied using hybrid spleen cells obtained from experimentally naive or from immunized mice. Antikeratin antibodies were detected by enzyme-linked immunosorbent assay (ELISA) in 5.9-9.5% of the culture supernatants of fused spleen cells taken from naive mice. When mice were immunized with keratins, the number of supernatants containing antikeratin antibodies was increased to eight out of 51 (15.7%). When immunized with non-keratin materials such as activated human T cells, adult T-cell leukaemia cell lysates, and human T-cell lymphotropic virus type-I (HTLV-I), 16.7-20.8% of the supernatants were found to contain antikeratin antibodies by ELISA. The antikeratin antibodies in the supernatants showed cytoplasmic staining of keratinocytes in human as well as mouse skin by indirect immunofluorescence. The antibodies reacted with extracted human epidermal keratins by dot-blot and Western blot analysis. Most antikeratin antibodies in the supernatants did not show cross-reactivity with exogenous antigens used for immunization and vimentin-type intermediate-sized filaments. These findings demonstrate that B cells producing antikeratin antibodies are common in naive mice, and produce various types of antikeratin antibodies following specific activation with epidermal keratins and non-specific immunological stimuli.

Animals↗
PubMed1990

Development of computer-aided motion analyzing (CAMA) system for radiopaque implanted tilting disk heart valves.

The newly developed semiautomatic data acquisition and processing system allows progress in quantitative evaluation of functions of implanted tilting disk valves. In the new system, data acquisition could be carried out semiautomatically by utilizing image processing methods, and the data analysis time was shortened. The system consists of a computer-controlled cinefilm loading device, a CCD camera, a frame memory, a superimposer, and CRT displays. Since series of the open- and shut-mode frames are commonly observed by turns in normal subjects, data acquisition was carried out manually at the first frame of each mode and semiautomatically from the second frame to the last. By processing the image data with the binarization method, the valve contours were detected, and an open angle and other motion properties can be obtained. Analyzing 90 frames of the cinefilm, this system analyzes data in a time period 20 min shorter than the manual procedure. With the implanted Medtronic Hall valve, a 60 to 65 degrees open angle was calculated.

Cineradiography↗
PubMed1990

Latent transcripts of Marek's disease virus are clustered in the short and long repeat regions.

Marek's disease herpesvirus (MDV) induces tumors in chickens, and lymphoblastoid cells derived from such tumors contain the viral genome in a latent state and do not produce infectious virus. Poly(A)+ RNAs extracted from MDV-induced kidney lymphoma cells and from MKT-1 cells, a nonproducing lymphoblastoid cell line derived from a tumor induced by MDV, were electrophoretically separated under denaturing conditions, transferred to a solid substrate, and hybridized with labeled DNA probes representing approximately 95% of the virus genome. These analyses revealed 29 viral RNA transcripts in the kidney lymphoma and 32 viral RNAs in MKT-1 cells. In both instances, the transcripts hybridized to a restricted region comprising approximately 20% of the MDV genome located in the repeats flanking the long and short unique sequences and in the adjacent unique sequences. The sizes of the transcripts derived from kidney lymphoma and MKT-1 cells and the distributions of the homologous regions in the viral genome were very similar. The most abundant transcripts were homologous to the BamHI I2 fragment. The results suggest that expression of the MDV genome in MKT-1 cells closely reflects the expression of the MDV genome in tumors. The gene expression over extended regions of the genome is in concordance with that observed in latent gammaherpesviruses rather than that observed in latent alphaherpesviruses.

Cell Line↗
PubMed1990

[Study on method for examining bone quality for dental implant. Relationship between cutting force and bone mineral content].

A number of factors, including, for example, patient jawbone condition, influence prognosis of dental implants. At present, X-ray and intraosseous punctures are employed as means of examining bone quality. But lack of definite criteria makes objective evaluation difficult. In order to develop a more reliable method for making objective evaluations of bone quality for dental implant, this study quantitatively measured the cutting force at an intraosseous puncture and investigated its relation to bone mineral content, a parameter of bone condition. Methods One side of each of 4 mandibles obtained from adult Japanese cadavers was fixed with formalin. The mandibles were free of deformity and injury to the jaw or face but lacked molars (these materials were the property of the Department of Anatomy, the Tokyo Dental College). Drilling tests were made in 5 samples taken from each of the 4 mandibles (20 in all), and bone mineral content was measured. Prior to the drilling test, the dental engine was remodeled to produce an experimental test machine permitting quantitative measurement of the cutting force (cutting torque) exerted on cutting instrument in the direction of rotation. The device was fitted to a universal testing machine and constant-feed-speed drilling tests were performed. Cutting force on the cutting instrument produced during drilling was divided into cutting torque (cm-g) in the direction of rotation and cutting load (gf) in the direction of feeding. Densitometry and image analysis were used to measure bone mineral content. X-ray photograph were taken from each sample with an aluminum reference, the density of which was digitalized and measured. The density value was then image analyzed, and bone mineral content of the drilled site was obtained as relative value calculated in aluminum equivalent (mmAl). Comparative examinations of cutting torque, cutting load, and bone mineral content were made through the same drilled site at every 1.0 mm-depth from surface. Results and Conclusions 1. The experimental test machine permitted quantitative measurements of the cutting force exerted on the cutting instrument in the direction of rotation (cutting torque). 2. Quantitative measurements on the cutting force during drilling produced the following values: cutting torque--0.4 to 56.5 cm-g with an average of 8.7 cm-g; cutting load--1.7 to 1419.7 gf with an average of 169.3 gf. 3. Bone mineral content at the drilled site ranged from 0 to 0.67 mmAl and averaged 0.19 mmAl.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[Effects of trospium chloride on the lower urinary tract function].

The effects of trospium chloride on the lower urinary tract function were studied by combined recording of cystometry and sphincter electromyogram in 13 decerebrated dogs. Micturition was induced by bladder filling before and after drug administration. A statistical analysis was carried out on the urodynamic parameters. Trospium chloride at the dose of 0.1 mg/kg showed a small but significant decrease in the threshold pressure during the collecting phase. In the urodynamic parameters of the emptying phase which is considered to be influenced by cholinergic activity, there was a significant decrease in maximum bladder pressure at 0.03, 0.1, and 0.3 mg/kg and a significant increase in residual urine at 0.3 mg/kg. Trospium chloride is probably acting as a antimuscarinic agent in this study. Trospium chloride appears to be useful for the relief of symptoms associated with hyperactive bladder contraction.

Animals↗
PubMed1989

Cholecystokinin antagonism by anthramycin, a benzodiazepine antibiotic, in the central nervous system in mice.

Anthramycin (ATM) which is a product of some streptomyces micro-organisms was shown to antagonize the central effects of cholecystokinin (CCK) such as antinociception and satiety and to displace CCK bound to the slices from the brains of mice. Sulfated octapeptide CCK (CCK8) was administered intracisternally to mice at doses of 1 microgram/mouse for inducing antinociception and 200 ng/mouse for satiety. ATM was administered intraperitoneally to mice at doses such as 0.3 and 0.5 mg/kg. CCK8-induced antinociception and satiety were significantly reversed by ATM in those doses. [125I]CCK8 binding to the brain slices was observed autoradiographically. The autoradiograms from the slices were converted to false color images by using a microcomputer. The radioactivity in the autoradiograms was expressed by color spectra in the false color images. Comparison of the binding of [125I]CCK8 to the brain slices in the presence and the absence of ATM revealed that ATM (10(-6) M) clearly displaced the CCK8 binding in the various regions, especially in the cortex, of the brain. These findings suggest that ATM acts as an potent antagonist of CCK in the central nervous system in mice.

Animals↗
PubMed1989

Effect of huperzine A, a new cholinesterase inhibitor, on the central cholinergic system of the rat.

The present study represents the first comprehensive investigation of the effect of huperzine A (HUP-A), a new cholinesterase inhibitor (ChEI) isolated from a Lycopodium species, upon acetylcholinesterase (AChE) activity, acetylcholine (ACh) levels and release, and cholinergic receptors in rat brain following acute i.m. or i.p. administration. The study shows that HUP-A can produce a long-term inhibition of AChE activity in brain (up to 360 min) and an increase in the ACh levels up to 40% at 60 min. There is considerable regional variation in the degree of ACh elevation after HUP-A with maximal values seen in frontal (125%) and parietal (105%) cortex and smaller increases (22-65%) in other brain regions. HUP-A at concentrations of 10(-6) to 10(-4) M does not significantly alter the electrically evoked release of 3H-ACh from cortical slices. With the exception of the highest concentrations (6 X 10(-4) M) the displacement effect of HUP-A for cholinergic ligands is stronger for 3H-(-)nicotine than for 3H-QNB. A parallel autoradiographic study in the mouse shows that 60 min after i.v. injection (183 micrograms/kg) the drug is present in all brain regions, but it is particularly concentrated in certain areas such as frontoparietal cortex, nucleus accumbens, hippocampal, and striatal cortex. Radio-activity is practically absent in the whole body at 12 hr. Our study suggests that this new ChEI has interesting cholinomimetic properties, and its effects satisfy more closely established criteria for an ideal ChEI for therapeutic use than previously tested compounds.

Acetylcholine↗
PubMed1989

Effect of cerebellectomy on reflex micturition in the decerebrate dog as determined by urodynamic evaluation.

The effect of cerebellectomy on reflex micturition in the decerebrate dog was investigated by cystometric and striated urethral sphincter EMG studies. Before and after cerebellectomy, reflex micturition consisting of bladder contraction and spasmodic contraction of the striated urethral sphincter occurred when a critical degree of filling was reached. Cerebellectomy showed no influence on the striated urethral sphincter EMG activity. However, cerebellectomy produced a significant decrease in threshold volume and threshold pressure during the collecting phase, and also in the contraction pressure and voided volume of the emptying phase. The present study suggests that the cerebellum plays an inhibitory role in the collecting phase and a facilitatory role in the emptying phase during the entire reflex micturition cycle of the decerebrate dog. Further study will have to be done concerning the neurotransmission mechanism that causes these different effects in the collecting and emptying phases.

Animals↗
PubMed1989

Application of Doppler color flow imaging method on the detection of vesicoureteral reflux.

The doppler color flow imaging method was employed to detect the vesicoureteral reflux. The ultrasound examination was performed by using the doppler color flow imaging system. Ultrasonic sector scan was carried out by the use of the 3.75 MHz phased array and/or conbex array transducer with a transabdominal approach. The flow in the bladder from the ureteral orifice to the bladder was detected with a red color indicating the direction towards the probe and the flow from the bladder towards the ureteral orifice during the vesicoureteral reflux was detected with a blue color indicating the direction away from the probe. The doppler color flow imaging method appears to be a useful diagnostic procedure for the detection of the vesicoureteral reflux.

Child, Preschool↗
PubMed1989

[Effect of high-frequency oscillation on hypoxic pulmonary vasoconstriction].

We studied the effect of high-frequency oscillatory ventilation (HFO) on hypoxic pulmonary vasoconstriction (HPV) in mongrel dogs. Arterial blood gas as well as pulmonary and systemic hemodynamic variables were measured. Using a double-lumen endotracheal catheter, the right lung was ventilated by controlled mechanical ventilation (CMV) and the left lung was ventilated by CMV (controlled group, n = 5), HFO (HFO group, n = 6) and a combined use of CMV and HFO (combined group, n = 6). Under the same condition as in HFO group, chest was opened and the left pulmonary arterial flow was determined by electromagnetic method (opened thorax group, n = 4). Bilateral lungs were ventilated with pure oxygen during the control period. The right lung was ventilated with pure oxygen while the left lung was ventilated with pure nitrogen afterward during the study. There was no significant change in arterial oxygen partial pressure due to delayed HPV in HFO group or combined group between 30 and 120 minute values. Although there was an increase in mean pulmonary arterial pressure in combined group, in HFO group it was not observed. At the same time, the decrease in pulmonary flow was minimum in open thorax group. Authors conclude that HFO interferes with the effect of HPV to a certain extent.

Animals↗
PubMed1989

[Production of monoclonal antibodies to human T-cell lymphotropic virus type 1 (HTLV-1) and studies of their specificity].

Mouse monoclonal antibodies to HTLV-1 core proteins, p19 and p24, were obtained by hybridoma technique. The specificity was studied by indirect immunofluorescence, enzyme-linked immunosorbent assay (ELISA), dot blot, and Western blot studies. Polyclonal antibodies reactive with HTLV-1 viral proteins were raised by rabbits and guinea pigs. A sandwich ELISA and a dot blot method using these antibodies detected the soluble viral antigens in the ATL cell lysate and ATL culture media. No reaction was observed when IL-2-activated human T-cell lysate and the culture media were used as controls. These data showed that our sandwich ELISA and dot blot systems are available for quantitative analysis of the soluble HTLV-1 viral antigens and contribute to understanding the ability of viral replication by ATL cells.

Animals↗
PubMed1988

Pontine micturition center in the dog.

The function and location of the pontine micturition center was studied in ten decerebrate dogs by physiological experiments in which micturition induced by electrical stimulation of the pontine micturition center was compared with reflex micturition in response to bladder filling with physiological saline and by histological studies of the electrolytic lesions made at the stimulated areas. The micturition induced by electrical stimulation of the pontine micturition center showed the same pattern of detrusor contraction, simultaneous urethral relaxation and the elevation of the tail as reflex micturition in response to bladder filling. The peak contraction pressures in both micturitions showed no obvious differences. The electrolytic lesions were histologically identified at the locus coeruleus alpha in six out of 10 dogs, at the locus coeruleus in three and at the peri locus coeruleus alpha in one dog. The coordinated activities of bladder and urethra in the micturition induced by electrical stimulation of locus coeruleus or its subparts suggest that these areas perform an important role in the urine emptying function.

Animals↗
PubMed1988

Autoradiographic demonstration of the antagonism of anthramycin and diazepam against cholecystokinin in the mouse brain using the [14C]-2-deoxyglucose method.

Effects of diazepam (DZP), a synthetic benzodiazepine drug, and anthramycin (ATM), a benzodiazepine antitumor antibiotic produced by a certain species of streptomyces, on the uptake of 2-deoxy-D-[14C]-glucose (2-DG) in mouse brain neurons with or without cholecystokinin were examined. 2-DG uptake in neurons was evaluated by using an autoradiographic technique. The sulfated octapeptide CCK (CCK8) was injected intracisternally; DZP and ATM, intraperitoneally; and 2-DG, intravenously to mice. Autoradiograms prepared from the slices of the brain were converted to false color images. CCK8 (1 microgram/mouse) markedly stimulated the 2-DG uptake in neurons in the various regions of the brain, but the stimulative effects of CCK8 was almost completely suppressed after an intraperitoneal administration of 1.0 mg/kg of DZP or 0.5 mg/kg of ATM. Since it has been previously shown that these doses of DZP and ATM almost completely reversed the antinociception produced by 1 microgram/mouse of CCK8, the present results on the 2-DG uptake in the mouse brain are considered to further support the antagonism between CCK8 and DZP or ATM in the central nervous system.

Animals↗
PubMed1988

2-deoxy-D-(14C)-glucose study of the interaction of caerulein and apomorphine.

The interaction of ceruletide (CER) and apomorphine (APO) was studied in mice. APO and CER were injected subcutaneously. In wheelcage experiments, lower doses (50 to 100 micrograms/kg) of APO depressed dose-dependently the locomotor activity in mice, but a higher dose (1 mg/kg) of APO produced a smaller effect than 100 micrograms/kg of APO. CER (20 micrograms/kg) slightly depressed the locomotor activity in mice. The coadministration of APO and CER caused stronger inhibition in the locomotor activity than the single administration of these drugs. The effects of APO and CER on the neuronal uptake of 2-deoxy-D-(14C)-glucose (2-DG) were also examined. APO (50 and 1000 micrograms/kg) inhibited the 2-DG uptake in most regions of the brain, although the inhibitory effect was larger at lower doses. CER inhibited the 2-DG uptake in some regions, but enhanced it in others. The combination of APO and CER markedly enhanced the 2-DG uptake. Thus, it was difficult to correlate the effects of the combination of APO and CER on locomotor activity with 2-DG uptake.

Animals↗