Search PubMed⌕ Search

Biomedical subjects

S Kikuchi

Publications and source records attributed to S Kikuchi.

At least 271 records · Page 15Linked to original sources
PubMed1996

Inhibitory effect of a novel orally active GP IIb/IIIa inhibitor, SC-54684A on intimal thickening in the guinea pig femoral artery.

The inhibitory effect of a novel orally active platelet membrane glycoprotein receptor complex IIb/IIIa (GP IIb/IIIa) inhibitor, SC-54684A is studied on intimal thickening in the guinea pig femoral artery. A segment of the femoral artery was occluded by a platelet-rich thrombus induced by photochemical reaction between systemically administered Rose Bengal and transluminal green light which causes endothelial injury followed by platelet adhesion and aggregation at the site of photochemical reaction. Three weeks after successful thrombolysis by tissue-type plasminogen activator, intimal thickening occurred at the irradiated site. SC-54684A (30 mg/kg), administered 2 h before photochemical reaction, significantly (P < 0.05) prolonged the time to occlusion of the femoral artery; in this respect aspirin (100 mg/kg) was ineffective. A combination of SC-54684A and recombinant tissue-type plasminogen activator (rt-PA) increased the frequency of reopening and significantly (P < 0.05) prolonged the duration of reflow compared with rt-PA alone. Further, SC-54684A administered orally twice a day for 3 weeks significantly (P < 0.05) inhibited intimal thickening but aspirin, administered orally once a day for 3 weeks, was ineffective. Scanning electron microscopy revealed extensive platelet adhesion and aggregation on the denuded vessel walls in the untreated group 24 h after successful thrombolysis. In separate experiments, SC-54684A markedly inhibited platelet aggregation ex-vivo. Inhibition of platelet adhesion and aggregation at the site of endothelial injury by SC-54684A (via GPIIb/IIIa inhibition) may account for its inhibitory effect on intimal thickening.

Angioplasty, Balloon, Coronary↗
PubMed1996

Ophthalmic tumor formation in Waldenström's macroglobulinemia.

Waldenström's macroglobulinemia is a malignant disease of the reticuloendothelial system; ocular complications reported previously have been concerned chiefly with hyperviscosity manifestations. Ophthalmic tumor formation is rare, although not unheard of, in this particular condition. This report describes two rare instances of Waldenström's macroglobulinemia which involved conjunctival and orbital tumors. One patient developed the tumors after a lengthy clinical course; in the other patient, eyelid and orbital tumors were the first symptoms. Careful examination of the external eye, especially the fornix of the conjunctiva, in patients with Waldenström's macroglobulinemia can identify an initial lesion or invasions to other organs.

Adult↗
PubMed1995

A model for acute, chronic, and delayed graded compression of the dog cauda equina. Presentation of the gross, microscopic, and vascular anatomy of the dog cauda equina and accuracy in pressure transmission of the compression model.

STUDY DESIGN: A new model for controlled, graded compression of the dog cauda equina was developed using the dog lumbar spine. The model was defined regarding macroscopic, microscopic, and vascular anatomy and regarding accuracy in pressure transmission. OBJECTIVES: The study was performed to develop a model for controlled, graded compression that would allow for acute, chronic, and delayed compression. SUMMARY OF BACKGROUND DATA: There has been an increasing interest for the reactions of the spinal nerve roots to mechanical deformation. The previously used models have had limitations regarding the duration and the onset of the compression and possibilities for a controlled variation of the compression pressure on chronically compressed nerve roots. METHODS: Macroscopic examination, light microscopy, and ink injection of the vasculature was used to assess the anatomic characteristics of the nerve tissue and the vasculature of the cauda equina in the dog lower lumbar spine. The relation between known pressures in the compression balloon used to compress the cauda equina and the pressure in the central thecal sac was assessed by measuring the pressure in an artificial thecal sac with a pressure transducer. RESULTS. The neural and vascular anatomy was found to have a close resemblance to the human cauda equina. The pressure in the thecal sac was within 5% of the pressure in the compression balloon at various pressures between 0-200 mm Hg. CONCLUSION: The presented model provides a good pressure transmission to the dog cauda equina, which has an anatomy that closely resembles the human cauda equina. The model may be well suited for physiologic studies of cauda equina compression. A double-balloon system may provide unique opportunities to induce chronic compression and delayed compression, i.e., additional compression after a certain time of chronic compression to resemble the changes in pressure that are characteristic for neurogenic claudication.

Animals↗
PubMed1995

A model for acute, chronic, and delayed graded compression of the dog cauda equina. Neurophysiologic and histologic changes induced by acute, graded compression.

STUDY DESIGN: The results of acute compression on nerve function and morphology were analyzed in a recently developed model for graded cauda equina compression in the dog. OBJECTIVES: The model was developed to better mimic the clinical situation of cauda equina compression in association with spinal canal stenosis. SUMMARY OF BACKGROUND DATA: The compression of the cauda equina has been induced by metal clips, plastic bands, constrictors, and inflatable balloons. No model has used the intact spinal canal and induced compression by increasing the pressure per se in the canal. METHODS: An inflatable balloon with a diameter exceeding the diameter of the spinal canal was placed under the lamina of the L7 vertebra in the dog. The balloon was inflated to various pressures, and muscle action potential area and nerve conduction velocity were monitored during 2 hours of compression and 1.5 hours of recovery. Nerve root specimens were processed for light microscopic examination. RESULTS: There was a progressive reduction of muscle action potential area and nerve conduction velocity that was proportional to the applied pressure. Histologic evaluation revealed no nerve fiber damage but a slight intraneural edema after compression at 200 mg Hg. CONCLUSIONS: The presented model may provide reproducible results regarding neurophysiologic and morphologic effects after acute, graded compression of the dog cauda equina. Two additional conclusions can be made from this study. First, the area measurement of the MAP is probably well suited for recordings and analyses of changes in muscle action potentials. Second, the specific onset rate of this study, in relation to previous studies, indicates that there is a threshold for the compression onset rate for inducing additional nerve injury located in the interval 0.1-0.8 seconds. The results from the present study provides important baseline data for the continued studies on chronic and intermittent compression with the compression model.

Action Potentials↗
PubMed1995

Finding of a homarine-synthesizing enzyme in turban shell and some properties of the enzyme.

A homarine-synthesizing enzyme was found for the first time in cell-free extract from turban shell (Batillus cornutus) and the enzyme was purified 36.2-fold and characterized. Properties of the enzyme were as follows: substrates were picolinic acid (pyridine-2-carboxylic acid) and S-adenosyl-L-methionine; optimum temperature for the enzymic reaction was 25 degrees C; optimum pH for the enzymic reaction was 6.3; and the Km values for picolinic acid and S-adenosyl-L-methionine were calculated at 317 and 14.5 microM, respectively. Among pyridine carboxylic acids, only picolinic acid was methylated with S-adenosyl-L-methionine by this enzyme. The molecular weight of the enzyme was estimated to be 70,800. The enzyme activity was inhibited by heavy metal ions, S-adenosyl-L-homocysteine, adenosine, homocysteine, and sinefungin. Homarine, which is an osmotic pressure regulator, morphogen, etc.; is enzymatically synthesized by the methylation of picolinic acid with S-adenosyl-L-methionine and the enzyme activity may be controlled by S-adenosyl-L-homocysteine (reaction product) and its related compounds.

Adenosine↗
PubMed1995

Serum anti-Helicobacter pylori antibody and gastric carcinoma among young adults. Research Group on Prevention of Gastric Carcinoma among Young Adults.

BACKGROUND: Helicobacter pylori is recognized as one of the possible causes of gastric carcinoma. There have been few studies on the relationship between H. pylori and gastric carcinoma in patients younger than 40 years. METHODS: Data and sera were collected from the cases (105 hospitalized patients younger than 40 years with gastric carcinoma from 9 hospitals in the Kanto-Shin-Etsu Area in Japan) and controls (102 hospitalized control subjects and 101 screening control subjects) whose sex and age (within 4 years) were matched. The serum anti-H. pylori immunoglobulin G antibody was measured, and the odds ratio (OR) for the association between seropositivity and gastric carcinoma was calculated. RESULTS: The OR (95% confidence interval) was 13.3 (5.3-35.6). For women, the OR was 32.8, whereas for men it was 6.8. The OR for patients with early gastric carcinoma was 20.8, and for patients with advanced disease, it was 10.8. The OR for intestinal-type carcinoma was 18.0, and for diffuse-type carcinoma, it was 12.8. The OR for proximal carcinoma was 11.3, and for distal carcinoma it was 14.8. CONCLUSION: The OR for these young subjects was considerably larger than that for the older subjects in previously published studies. Among those younger than 40 years of age, early stage carcinoma has a stronger association with H. pylori than advanced carcinoma, and intestinal- and diffuse-type carcinomas have an association with H. pylori.

Adolescent↗
PubMed1995

Intermittent cauda equina compression. An experimental study of the porcine cauda equina with analyses of nerve impulse conduction properties.

STUDY DESIGN: Neurophysiologic reactions of cauda equina nerve roots to intermittently applied compression were assessed for two different modes of compression using a porcine model. OBJECTIVE: To assess the neurophysiologic reactions of cauda equina nerve roots to intermittently applied compression. SUMMARY OF BACKGROUND DATA: A number of experimental studies have been presented recently regarding the reaction pattern of spinal nerve roots to compression. These studies have used a continuous pressure level. For studies of pathophysiologic mechanisms behind neurogenic claudication, however, it would be more relevant to study the effects of intermittently applied compression. METHODS: The cauda equina was exposed and compression was applied by two inflatable balloons. Two different modes of compression were used. Either the two balloons were inflated and deflated simultaneously (intermittent compression), or just the caudal balloon was inflated and deflated while the cranial balloon was kept continuously inflated (continuous/intermittent compression). The experimental series were: intermittent compression at 10 mm Hg (n = 5) and 50 mm Hg (n = 5), and continuous/intermittent compression at 10 mm Hg (n = 5) and 50 mm Hg (n = 5). For both modes of compression the pressure in the balloons with intermittent inflation was maintained for 10 minutes and deflated for 5 minutes. This procedure was repeated in 8 cycles for 2 hours. Muscle action potentials were recorded in the tail muscles. RESULTS: Compression at 10 mm Hg induced similar reductions of muscle action potentials for both compression modes. At 50 mm Hg, the effects were more pronounced at continuous/intermittent compression than at intermittent compression. The reduction of muscle action potentials was slightly more pronounced for 50 than for 10 mm Hg at intermittent compression. However, a statistically significant difference in the results was found only between 10 and 50 mm Hg at the continuous/intermittent compression mode. CONCLUSIONS: The established model allows investigation of the effects of intermittent cauda equina compression, which might be clinically more relevant than continuous compression regarding the pathophysiologic mechanisms behind neurogenic claudication.

Action Potentials↗
PubMed1995

Nerve root infiltration and sympathetic block. An experimental study of intraradicular blood flow.

STUDY DESIGN: The nerve root of L7 was exposed, and a clamp was applied to simulate radiculopathy. Intraradicular blood flow was measured at the takeoff point of the nerve root and at the distal to the dorsal root ganglion before and after nerve root infiltration with 2% lidocaine or physiological saline solution (control group), or sympathetic ganglion block with 2% lidocaine. OBJECTIVES: To investigate one of the mechanisms of the therapeutic effect of nerve root infiltration by assessing changes in intraradicular blood flow. SUMMARY OF BACKGROUND DATA: Increased intraradicular blood flow was noted both proximal and distal to the clamp after nerve root infiltration or sympathetic ganglion block with 2% lidocaine. No increase was seen after nerve root infiltration with saline solution. Macroscopic and microscopic examination showed that dye after nerve root infiltration did not spread beyond the clamped region to the proximal site. METHODS: Intraradicular blood flow was measured with a tissue blood flowmeter using the electrolytic hydrogen clearance method before and after nerve root infiltration with 2% lidocaine or physiologic saline solution (control group), or sympathetic ganglion block with 2% lidocaine. RESULTS: Increased intraradicular blood flow was noted both proximal and distal to the clamp after nerve root infiltration or sympathetic ganglion block with 2% lidocaine. No increase was seen after nerve root infiltration with saline solution. CONCLUSIONS: An increase in intraradicular blood flow is related to one of the mechanisms of the therapeutic effect of nerve root infiltration. This effect may be mediated by the sympathetic nervous system.

Animals↗
PubMed1995

Sympathetic and sensory innervation of the rat shoulder joint: a WGA-HRP tracing and CGRP immunohistochemical study.

The innervation of the shoulder joint of the rat was investigated. Nerve origin was assessed by injection of a neuronal tracer (WGA-HRP) into the shoulder joint cavity and calcitonin gene-related peptide (CGRP), which is known to be present in some sensory neurons, was detected immunohistochemically with an anti-CGRP antibody. In the ipsilateral sympathetic and dorsal root ganglia, 133-312 and 12-55 nerve cell bodies were respectively labeled by injection of the tracer. In the sympathetic ganglia, 83% of all labeled cells were found in the stellate ganglion and 17% in the superior cervical ganglion. In the dorsal root ganglia, 75% of the labeled cells were found in C4 and the neighboring ganglia (C4-C5), while the rest were observed in C6-8 and T3. This suggested that the origin of sensory innervation for the shoulder joint was mainly in the mid-cervical cord. CGRP-immunoreactive fibers were found in the synovial capsule of the shoulder joint. These fibers were fine and resembled type 4 axons as classified by Brodal, i.e., nerve related to pain sensation. These findings indicate that sensory nerves from the mid-cervical cord and sympathetic nerves from the cervical ganglion are distributed to the shoulder joint. It is possible that these nerves are related to symptoms such as pain in patients with "frozen" shoulder or other diseases.

Animals↗
PubMed1995

Origin of the calcitonin gene-related peptide-immunoreactive nerve fibers in the rat shoulder joint.

The rat shoulder joint capsule is innervated by thin sympathetic and sensory nerve fibers, most of which contain calcitonin gene-related peptide (CGRP). In order to establish the origin and distribution of CGRP-immunoreactive (IR) fibers, wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the shoulder joints of rats via a dorsal surgical approach. After WGA-HRP injection, the cervico-thoracic dorsal root ganglia (DRG) were removed and processed using both HRP histochemistry and CGRP immunohistochemistry. In the C4 to C7 DRG, small to medium-sized neurons (20-40 microns) were labeled by this combined method. The number and size of the labeled neurons were measured in the cervical 4th-7th DRG. The number of double-labeled neurons was one quarter of the total number of HRP-labeled neurons and 1/20 of the CGRP-IR neurons. Most of the double-labeled cells were located in the C6 ganglion, and the mean number of double-labeled neurons was 13 at this level. This distribution and function of the CGRP-IR fibers in the rat shoulder joint capsule are discussed.

Animals↗
PubMed1995

Serum lipoprotein(a) concentrations and apolipoprotein(a) phenotypes in the families of NIDDM patients.

We studied the quantitative and qualitative characteristics of lipoprotein(a) [Lp(a)] as a function of apolipoprotein(a) [apo(a)] phenotype in 87 members (42 males, 45 females) of 20 diabetic families, 26 of whom were diagnosed with non-insulin-dependent diabetes mellitus (NIDDM) with moderate glycaemic control (HbA1c 7.1 +/- 1.2%). Apo(a) phenotyping was performed by a sensitive, high-resolution technique using SDS-agarose/gradient PAGE (3-6%). To date, 26 different apo(a) phenotypes, including a null type, have been identified. Serum Lp(a) levels of NIDDM patients and non-diabetic members of the same family who had the same apo(a) phenotypes were compared, while case control subjects were chosen from high-Lp(a) non-diabetic and low-Lp(a) nondiabetic groups with the same apo(a) phenotypes in the same family. Serum Lp(a) levels were significantly higher in NIDDM patients than in non-diabetic subjects (39.8 +/- 33.3 vs 22.3 +/- 19.5 mg/dl, p < 0.05). The difference in the mean Lp(a) level between the diabetic and non-diabetic groups was significantly (p < 0.05) greater than that between the high-Lp(a) non-diabetic and low-Lp(a) non-diabetic groups. An analysis of covariance and a least square means comparison indicated that the regression line between serum Lp(a) levels [log Lp(a)] and apo(a) phenotypes in the diabetic patient group was significantly (p < 0.01) elevated for each apo(a) phenotype, compared to the regression line of the control group. These data together with our previous findings that serum Lp(a) levels are genetically controlled by apo(a) phenotypes, suggest that Lp(a) levels in diabetic patients are not regulated by smaller apo(a) isoforms, and that serum Lp(a) levels are greater in diabetic patients than in non-diabetic family members, even when they share the same apo(a) phenotypes.

Apolipoproteins↗
PubMed1995

Inhibition of PDGF- and TGF-beta 1-induced collagen synthesis, migration and proliferation by tranilast in vascular smooth muscle cells from spontaneously hypertensive rats.

Vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) proliferate faster and are more sensitive to transforming growth factor-beta 1 (TGF-beta 1) than those of normotensive Wistar-Kyoto rats. We studied the in vitro effects of tranilast, an anti-allergic drug, on the proliferation, migration and extracellular matrix synthesis in the SHR-VSMC. There were many inhibitory effects of tranilast (30-300 microM) on SHR-VSMC. One is the effect on the proliferation stimulated with fetal bovine serum (FBS), TGF-beta 1 and platelet-derived growth factor-BB (PDGF-BB). Another is the effect on the PDGF-BB-induced migration. Lastly, tranilast exhibited inhibitory effects on spontaneous collagen synthesis and TGF-beta 1-induced collagen and glycosaminoglycan synthesis. On the other hand, collagen induced the VSMC migration concentration-dependently. These results suggest that tranilast may prevent restenosis after percutaneous transluminal coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1995

Macrophage inflammatory protein-1 alpha in the cerebrospinal fluid of patients with multiple sclerosis and other inflammatory neurological diseases.

The level of macrophage inflammatory protein-1 alpha (MIP-1 alpha), a newly discovered cytokine of chemokine family, was determined in cerebrospinal fluid (CSF) from 18 patients with multiple sclerosis (MS) and from control patients with other neurological disorders by an enzyme-linked immunosorbent assay (ELISA). The concentration of MIP-1 alpha in CSF was significantly elevated in MS in relapse (4.4 pg/ml) compared with non-inflammatory neurological disease control samples (0.3 pg/ml) (p < 0.0002). These concentrations in MS patients correlated well with leukocyte cell counts and protein content in CSF (r = 0.845, p < 0.0001; r = 0.853, p < 0.0001, respectively). In other inflammatory neurological disorders such as Behçet's disease and HTLV-1 associated myelopathy, significantly increased CSF levels of MIP-1 alpha were also observed. Chemokines are reported to play an important role in an early event of inflammation such as lymphocyte traffic. This report is the first study which confirmed the involvement of a chemokine in MS and other inflammatory neurological disorders.

Adult↗
PubMed1995

The association of smoking and drinking habits with serum pepsinogens.

BACKGROUND: The influence of smoking on serum pepsinogen I has been assessed. However, still to be assessed are the influences of smoking on pepsinogen II and drinking on serum pepsinogens. METHODS: Data were collected from 13,381 employees by questionnaire and serum tests. Multiple regression analyses were done with logarithms of serum pepsinogen I (LPI), pepsinogen II (LPII) or pepsinogen I/II ratio (LI/II) as a criterion variable and as categorized explanatory variables, sex, age, subjective symptoms in the stomach, past history of peptic ulcer, current smoking dose, past smoking amount, drinking habit and current drinking dose. RESULTS: Current smoking dose showed dose-dependent positive associations with LPI and LI/II: Past smoking amount yielded weakly dose-dependent negative associations with LPI and LI/II: Current drinking dose showed dose-dependent negative associations with LPI and LPII. CONCLUSION: Current smoking elevates pepsinogen I and the I/II ratio, and it may be necessary to consider the effect of smoking when pepsinogens are used as markers for gastric cancer. Drinking reduced pepsinogen I and II, but the effect was not so large.

Adult↗
PubMed1995

Physical fitness of 9 year olds in England: related factors.

STUDY OBJECTIVE: To examine the influence of social factors, passive smoking, and other parental health related factors, as well as anthropometric and other measurements on children's cardiorespiratory fitness. DESIGN: This was a cross sectional study. SETTING: The analysis was based on 22 health areas in England. PARTICIPANTS: The subjects were 299 boys and 282 girls aged 8 to 9 years. Parents did not give positive consent for 15% of the eligible sample. A further 25% of the eligible sample did not participate because the cycle-ergometer broke down, study time was insufficient, or they were excluded from the analysis because they were from ethnic minority groups or had missing data on one continuous variable. MEASUREMENTS AND MAIN RESULTS: Cardiorespiratory fitness was determined using the cycle-ergometer test. It was measured in terms of PWC85%-that is, power output per body weight (watt/kg) assessed at 85% of maximum heart rate. The association between children's fitness and biological and social factors was analysed in two stages. Firstly, multiple logistic analysis was used to examine the factors associated with the children's ability to complete the test for at least four minutes. Secondly, multiple linear regression analysis was used to examine the independent association of the factors with PWC85%. In the logistic analysis, shorter children, children with higher blood pressure, and boys with a larger sibship size had poorer fitness. In the multiple regression analysis, only height (p < 0.001) was positively associated, and the sum of skinfold thicknesses at four sites (p = 0.001) was negatively associated with fitness in both sexes. In girls, a positive association was found with pre-exercise peak expiratory flow rate (p < 0.05), and there were negative associations with systolic blood pressure (p < 0.05) and family history of heart attack (p < 0.05). In boys an association was found with skinfold distribution and fitness (p < 0.05), so that children with relatively less body fat were fitter. Social and health behaviour factors such as father's social class, father's employment status, or parents' smoking habits were unrelated to child's fitness. CONCLUSION: Height and obesity are strongly associated, and systolic blood pressure to a small extent, with children's fitness, but social factors are unrelated.

Blood Pressure↗
PubMed1995

Magnetic resonance angiographic findings in vertiginous patients with slow vertebrobasilar blood flow.

To investigate arterial lesions underlying slow vertebrobasilar blood flow (SBF) which appears as a high intravascular signal on proton-density images, we examined 35 vertiginous patients, 15 with SBF and 20 without, using magnetic resonance angiography. Vertebrobasilar dolichoectasia, segmental stenosis with elongation and diffuse narrowing of the vertebrobasilar arteries (VBA) were found in 4, 4 and 2 patients with SBF, respectively. In one patient with SBF, the thrombi that induced SBF seemed to have embolized to distal arteries. These abnormalities were not detected in patients without SBF, although 2 patients demonstrated aneurysm in the VBA. Because SBF is frequently associated with atherosclerotic arterial lesions, patients with SBF should be treated to prevent more severe ischemic brain disease.

Aged↗
PubMed1995

Apogeotrophic type of direction-changing positional nystagmus related to slow vertebrobasilar blood flow.

We examined the incidence of slow blood flow (SBF) in the vertebrobasilar system by magnetic resonance imaging (MRI) in 35 patients showing direction-changing positional nystagmus (DCPN). The subjects consisted of 20 patients with apogeotrophic type (group A) and 15 with geotrophic type (group B) of DCPN. Fifty-seven age-matched subjects without vestibular symptoms were examined as a control group (group C). SBF was detected in 11 (55%), 3 (20%) and 6 (11%) patients in groups A, B and C, respectively. Lacunae of the brainstem were found in 7 (35%) patients in group A and 1 (7%) in group B. The higher incidence of SBF in group A suggested a possible relationship between SBF and apogeotrophic type of DCPN. Apogeotrophic type of DCPN associated with SBF was considered to be caused by ischemia in the posterior circulation, though it was unclear whether the vestibular labyrinth or the hindbrain was mainly involved.

Adult↗