Search PubMed⌕ Search

Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 703 records · Page 39Linked to original sources
PubMed1995

Dirofilaria immitis: immunohistochemical localization of acid proteinase in the adult worm.

The distribution of Dirofilaria immitis acid proteinase in adult worm tissue was examined biochemically and immunohistochemically. About 45% of the total proteinase activity of 700g supernatant, which was obtained from the 0.25 M sucrose homogenate of live adult worms, was found in the 100,000g supernatant by subcellular centrifugation analysis. The distribution pattern of the proteinase activity observed by Percoll density gradient centrifugation coincided with that of glucose-6-phosphatase, a marker cytosolic enzyme, suggesting that the acid proteinase was present in vivo in a membrane-free form, possibly in the cytosol or secretory fluid. Immunostaining for the proteinase in the parasite tissue using the IgG1 (kappa-type) monoclonal antibody, H-1, revealed immunoreactive enzyme primarily inside the cell as small grains, but not on the cell surface, and immunoreactivity was distributed widely in worm tissues such as lateral cords, dorsal and ventral median cords, the anterior end of the parasite, and intestinal epithelial cells in granular form. In the male reproductive system, the testicular wall and germ cells were labeled with the antibody, and in the female, uterine walls, fertilized eggs, and developing eggs as well as microfilaria were labeled. In conclusion, D. immitis acid proteinase is widely distributed in the parasite tissue, possibly functioning not only in nutrition metabolism but also in production of sperm and microfilariae, etc.

Animals↗
PubMed1995

Blood flow velocity in the common carotid artery in humans during graded exercise on a treadmill.

Cerebral blood volume flow and flow velocity have been reported to increase during dynamic exercise, but whether the two increase in parallel and whether both increases occur as functions of exercise intensity remain unsettled. In this study, blood flow velocity in the common carotid artery was measured using the Doppler ultrasound method in eight healthy male students during graded treadmill exercise. The exercise consisted of stepwise progressive increases and decreases in exercise intensity. The peak intensity corresponded to approximately 85% of maximal oxygen consumption. During this exercise, the heart rate (fc), mean blood pressure (BP) in the brachial artery and mean blood flow velocity (vcc) in the common carotid artery increased as functions of exercise intensity. At the peak exercise intensity, fc, BP and vcc increased by 134.5%, 20.5% and 51.8% over the control levels before exercise (P < 0.01), respectively. The resistance index (RI) and pulsatility index (PI) were determined from the velocity profile and were expected to reflect the distal cerebral blood flow resistance. The RI and PI increased during the graded exercise, but tended to decrease at the highest levels of exercise intensity. As vcc increased with increases in exercise intensity it would be expected that cerebral blood flow would also increase at these higher intensities. It is also suggested that blood flow velocity in the cerebral artery does not proportionately reflect the cerebral blood flow during dynamic exercise, since the cerebral blood flow resistance changes.

Blood Flow Velocity↗
PubMed1995

Cerebral beta amyloid deposition in patients with malignant neoplasms: its prevalence with aging and effects of radiation therapy on vascular amyloid.

We examined immunohistochemically 123 autopsy brains from patients aged between 30 to 59, who died as a result of malignant neoplasms. Using antiserum to amyloid beta protein (A beta), we found that cerebral A beta deposits began in the subjects' fifth decade; its prevalence was 0%, 9.8% and 21.5% in the fourth, fifth and sixth decades, respectively. The major form of A beta deposition was diffuse-type plaques, although one third of the brains with A beta deposition showed amyloid angiopathy. Subpial A beta deposition is frequently associated with amyloid angiopathy. The prevalence of cerebral A beta deposits was about two times higher in the patients who had received brain radiation therapy (27.8%) compared to non-radiated patients (14.8%). Amyloid angiopathy was much more prominent (P < 0.05) with radiation therapy (22.2%) than without (8.0%). We found that cerebral A beta-deposition is dependent on aging, even in patients with malignant tumors and at beginning in their forties, and that brain radiation therapy is a possible risk factor of A beta deposition, especially in the form of amyloid angiopathy.

Adult↗
PubMed1995

Genotyping of ABO blood groups by PCR and RFLP analysis of 5 nucleotide positions.

The genotyping of ABO blood groups was performed using the polymerase chain reaction (PCR) method. The 4 DNA fragments containing the nucleotide position 261, 526, 703 and 796 of cDNA from A-transferase were amplified by PCR, and the amplified DNA subjected to restriction fragment length polymorphism (RFLP) analysis. The different nucleotide at position 803 was clearly distinguished by electrophoresis of the PCR products amplified with allele-specific primers. By analyzing the electrophoresis patterns, ABO genotyping was conclusively accomplished. The frequencies of ABO genotypes found in Japanese blood donors with A and B phenotypes were as follows: in the phenotype A group, AA = 19.8% and AO = 80.2%; and in the phenotype B group, BB = 12.8% and BO = 87.2%.

ABO Blood-Group System↗
PubMed1995

Protective effect of nitric oxide on development of acute pancreatitis in rats.

Nitric oxide (NO) has been implicated to regulate pancreatic circulation, promote capillary integrity, and inhibit leukocyte adhesion. We investigated the role of NO in the development of pancreatitis. Nitro-L-arginine, an inhibitor of NO synthase, in total dose of 35 mg/kg body wt was infused in the rats with edematous pancreatitis induced by two intraperitoneal injections of cerulein (20 micrograms/kg). L-Arginine (125 or 250 mg/kg), a NO donor was intravenously administered twice in the rats with hemorrhagic pancreatitis induced by water-immersion stress plus two intraperitoneal injections of cerulein (40 micrograms/kg). The degree of pancreas edema, serum amylase levels, and histologic alterations were investigated. Nitro-L-arginine exacerbated cerulein-induced pancreatitis and caused a decrease in pancreatic blood flow. L-Arginine ameliorated the severity of hemorrhagic pancreatitis dose dependently and improved the pancreatic blood flow. These findings suggest that NO could confer protection against the development of hemorrhagic pancreatitis, probably through improvement of the pancreatic microcirculation.

Acute Disease↗
PubMed1995

Myocardial recovery during post-ischemic reperfusion: optimal concentrations of Na+ and Ca2+ in the reperfusate and protective effects of amiloride added to cardioplegic solution.

The effects of Na+ and Ca2+ concentrations in the reperfusate on post-ischemic myocardial recovery were examined. Also, the myocardial protective effects of amiloride, an inhibitor of the Na+/Ca2+ and Na+/H+ exchange systems, added to cardioplegic solutions were assessed, using an isolated working rat heart perfusion system. Global myocardial ischemia was induced by 30-min normothermic cardioplegic arrest, using St. Thomas' solution. The concentration of Na+ in the reperfusate varied, stepwise, from 75 to 145 mM/l, and that of Ca2+, from 0.1 to 2.5 mM/l. In this study post-ischemic functional recovery was best at 110mM/l Na+ and 1.2-1.8 mM/l Ca2+ in the reperfusate. A significantly greater post-ischemic functional recovery and a lower creatine kinase release were observed when amiloride was added to the cardioplegic solution. Ca2+ overload via Na+/Ca2+ and Na+/H+ exchange systems would, thus, appear to be due, at least in part, to post-ischemic reperfusion injury.

Amiloride↗
PubMed1995

Haemodynamic, diuretic and hormonal responses to prostaglandin E1 infusion in halothane anaesthetized dogs: comparison among epidural lidocaine, epidural fentanyl and epidural saline.

Deliberate hypotension decreases blood loss and transfusion but it may be accompanied by adverse effects due either to the hypotensive agents themselves or to haemodynamic alterations. Prostaglandin E1 (PGE1) has the advantage of a diuretic effect coupled with systemic hypotension. To elucidate the mechanisms by which PGE1 induces diuresis we compared the haemodynamic, diuretic and hormonal responses to PGE1 infusion simultaneously with epidural lidocaine (EP-L n = 7), epidural fentanyl (EP-F n = 8) or epidural saline (CONT n = 7) in halothane anaesthetized mongrel dogs. All groups developed a decrease in mean arterial pressure during PGE1 infusion (from 105 +/- 24 to 77 +/- 18 mmHg in EP-L; 106 +/- 19 to 79 +/- 13 mmHg in the EP-F; and 129 +/- 14 to 106 +/- 18 mmHg in the CONT groups (mean +/- SD)) (P < 0.05). In the EP-F and CONT groups urinary output increased during PGE1 infusion (from 4.31 +/- 1.89 to 6.15 +/- 2.03 ml.min-1 and 2.71 +/- 1.23 to 4.48 +/- 1.66 ml.min-1 (P < 0.05), respectively) and was accompanied by increases in renal blood flow (from 87.0 +/- 40.7 to 111.0 +/- 42.8 ml.min-1 and from 121.6 +/- 46.6 to 158.4 +/- 64.9 ml.min-1 (P < 0.05), respectively) and in fractional excretion of sodium (FENa) (from 4.78 +/- 3.88 to 7.63 +/- 5.20% in CONT group).(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1995

Relation of saphenous vein graft obstruction to serum cholesterol levels.

OBJECTIVES: To determine the potential of lipid-lowering therapy to reduce saphenous vein graft obstruction, we retrospectively studied the association between graft obstruction and serum cholesterol levels. BACKGROUND: Atherosclerosis is the major cause of vein graft obstruction. Approximately 50% of grafts are occluded by 10 years after operation. It remains to be established whether lipid control affects long-term graft survival. METHODS: We carried out a retrospective review of all 284 patients who had undergone coronary artery bypass graft surgery at Juntendo University Hospital between 1976 and 1991 and met the following additional criteria: at least one saphenous vein graft, repeat coronary arteriography at some point after coronary artery bypass graft surgery and a serum cholesterol level > or = 200 mg/dl before operation. Saphenous vein graft obstruction rates were compared among three groups classified by serum cholesterol levels at follow-up arteriography: group I < 200 mg/dl; group II 200 to 239 mg/dl; group III > or = 240 mg/dl. A vein graft was considered obstructed if it was narrowed by > or = 70%. RESULTS: In group I, 88% of grafts were not obstructed 7 years after operation. The respective rates were 61% in group II and 57% in group III (p < 0.005). This relation was true for vein grafts to the left anterior descending and other coronary arteries. CONCLUSIONS: Lower serum cholesterol levels are associated with lower rates of vein graft obstruction for up to 7 years. This suggests that cholesterol-lowering therapy may improve long-term saphenous vein graft survival after coronary artery bypass surgery.

Aged↗
PubMed1995

Exercise-induced changes in R wave amplitude and heart rate in normal subjects.

An intermittent exercise protocol on a treadmill was used to examine six healthy subjects, and a steady protocol was applied to three of the subjects before and after short-term training. The peak blood velocity in the common carotid artery increased by 73.1% during the intermittent protocol and recovered to resting level within 3 minutes, while the heart rate (HR) remained high even 5 minutes after exercise. R wave amplitude (RWA) increased significantly from 1.40 +/- 0.39 mV at rest to 1.59 +/- 0.33 mV (P < .05) immediately after the start of walking, and decreased gradually to 1.46 +/- 0.36 mV (P < .05) during 3 minutes of walking. Thus, it decreased significantly to 1.31 +/- 0.40 mV (P < .01) during the interphase from exercise to rest, and increased again during recovery or rest periods in the intermittent protocol. The results suggest that an increase in the venous return per heart beat at the start of walking induces the increase in RWA, and that its abrupt decrease at the end of walking induces the decrease in RWA. Subjects with a higher HR response and recovery slopes have smaller abrupt changes in RWA at the interphases between rest and walking. The gradual decrease in RWA during walking may be related to a gradual increase in HR and a gradual decrease in systemic peripheral resistance, and the gradual increase in RWA after walking may be related to a gradual decrease in HR and a gradual increase in systemic peripheral resistance.

Adult↗
PubMed1995

Molecular analysis of lambda bio transducing phage produced by oxolinic acid-induced illegitimate recombination in vivo.

To study the mechanism of DNA gyrase-mediated illegitimate recombination in Escherichia coli, we examined the formation of lambda Spi- phage during prophage induction. The frequency of Spi- phage was two to three orders of magnitude higher in the presence of oxolinic acid, an inhibitor of DNA gyrase A subunit, than in the absence of the drug, while it was very low in nalAr bacteria with the drug. RecA function is not required for the formation of these phages, indicating that this enhancement is not caused by the expression of SOS-controlled genes. Analyses of att region and recombination junctions of Spi- phages revealed that they have essentially the same structures as lambda bio transducing phages but are classified into two groups with respect to recombination sites. In the majority class of the transducing phages, there were not more than 3-bp homologies between the parental E. coli bio and lambda recombination sites. In the minority class of the transducing phages, on the other hand, 9-10-bp homologies were found between the parental recombination sites. These results suggested that oxolinic acid-induced illegitimate recombination takes place by two variants of a DNA gyrase-dependent mechanism.

Bacteriophage lambda↗
PubMed1995

Mortality of Candida albicans-infected mice is facilitated by superinfection of Escherichia coli or administration of its lipopolysaccharide.

Pathogenesis of complex infection with Candida albicans and gram-negative bacteria was studied by determining the influence of infection with Escherichia coli or injection of E. coli lipopolysaccharide (LPS) on mortality of C. albicans-infected mice. Mice were infected intravenously with lethal doses of C. albicans, then treated intravenously at various times with viable E. coli or E. coli LPS, which individually were not lethal. Treatments 3 h after C. albicans infection clearly facilitated the death of the mice. Corresponding to this facilitated death, production of tumor necrosis factor (TNF) in sera was augmented 2 h after LPS injection into the infected mice. Similar increased production of TNF was also observed in mice treated with a nonlethal combination of heat-killed C. albicans and LPS. The number of viable C. albicans in kidneys of the infected mice was increased by LPS treatment, which was assumed to be the main cause of the greater mortality rate.

Animals↗
PubMed1995

The comparison of epidural fentanyl, epidural lidocaine, and intravenous fentanyl in patients undergoing gastrectomy.

This study was conducted prospectively to compare the effect of epidural fentanyl (EP-F), epidural lidocaine (EP-L), and intravenous fentanyl (IV-F) on hemodynamic and hormonal responses to surgery and postoperative analgesic requirement in 30 patients undergoing gastrectomy during isoflurane anesthesia. An epidural catheter was placed via the T8-9 interspace. Group EP-F received fentanyl 2 micrograms/kg in 10 mL saline, and Group EP-L, 10 mL 1.5% lidocaine, epidurally; Group IV-F was given fentanyl, 2 micrograms/kg, IV. Fifty percent of the original dose was repeated every hour. Hemodynamic data and plasma hormonal levels were compared between those before and those at 1 h after skin incision. The total number of analgesic administrations within the first 48 h postoperatively were compared. Group EP-L developed more frequent episodes of hypotension. Group IV-F required higher isoflurane concentrations and the plasma epinephrine levels increased more than in Groups EP-F and EP-L. In Groups EP-L and IV-F, the plasma antidiuretic hormone (ADH) level increased more than in Group EP-F. In Groups EP-F and IV-F, the plasma cortisol and adrenocorticotropic hormone (ACTH) levels increased more than in Group EP-L. The use of postoperative analgesics was significantly less in Group EP-F. In conclusion, in Group EP-F, attenuated hormonal responses to surgery was accompanied with less hypotension and postoperative analgesic requirements were reduced.

Adjuvants, Anesthesia↗
PubMed1995

Plasma thrombomodulin levels in coronary sinus blood in patients with coronary artery disease.

Plasma thrombomodulin (TM) levels in coronary sinus blood were measured in 15 patients with coronary artery disease who underwent elective PTCA (group A). TM was also measured in eight patients with coronary artery disease (group B) and six patients without coronary artery disease (group C), who only underwent diagnostic coronary angiography. The baseline level was 21.6 +/- 3.4 U/ml in group A, and 21.0 +/- 4.9 in group B, and both levels were slightly higher (P < 0.05) than those in group C (15.1 +/- 3.3). In group A, the level increased to 27.5 +/- 8.3 (P < 0.01) immediately after PTCA and then returned to 22.2 +/- 5.1 by 24 h. In groups B and C, levels showed no change immediately after angiography. In group A, the percentage increase in the TM level immediately after PTCA from that before the procedure correlated with the number of balloon inflations (r = 0.76, P < 0.01). In conclusion, the plasma TM level in coronary sinus blood might indicate endothelial damage due to atherosclerotic coronary artery disease and an increase in the level after PTCA might directly indicate vascular injury by balloon inflation.

Aged↗
PubMed1995

Localization of nitric oxide synthase in spinal nuclei innervating pelvic ganglia.

We employed retrograde axonal tracing techniques and nitric oxide synthase (NOS) and choline acetyltransferase (ChAT) immunohistochemistry to identify NOS-containing neuronal populations within the lumbosacral spinal cord and determine whether these project to the major pelvic ganglion in the adult male Sprague-Dawley rat. Immunohistochemical localizations of NOS included neurons situated at the L5 to S2 segments of the spinal cord, which corresponded to the sacral parasympathetic nucleus. Another prominent locus for NOS was a group of neurons identified in the L1 segment corresponding to the dorsal commissural nucleus. These regions correlated directly with preganglionic parasympathetic and sympathetic neuronal origins, respectively, which were established with ChAT colocalizations. Retrograde tracing verified the projection of these neurons to the pelvis. Additional neuronal localizations of NOS were observed throughout the intermediolateral cell column, involving the superficial laminae of the dorsal horn, in the region surrounding the central canal and occasionally in the medial area of the ventral horn. These results indicate that the regulation of pelvic visceral activity may involve NO-based neuronal mechanisms operating at the level of the lumbosarcal spinal cord.

Amino Acid Oxidoreductases↗
PubMed1995

Suppression of anti-Candida activity of murine neutrophils by progesterone in vitro: a possible mechanism in pregnant women's vulnerability to vaginal candidiasis.

Sex steroid hormones were examined for their effect on mycelial growth of Candida albicans, and the inhibitory activity of casein-induced murine peritoneal neutrophils against mycelial growth of C. albicans was examined in vitro using a crystal violet staining method or a [3H]glucose incorporation method. Four steroid hormones, danazol, estradiol, estriol and testosterone had no effect on mycelial growth of C. albicans, but progesterone appeared to convert the growth form of C. albicans from hyphal to yeast. Danazol (10(-6) M) and progesterone (10(-5) M) suppressed anti-Candida activity of neutrophils of non-treated mice, while testosterone, estradiol, and estriol did not. The anti-Candida activity of neutrophils of estradiol-pretreated mice was clearly suppressed by progesterone even at 10(-6) M which corresponded to its plasma concentration in pregnant women in the third trimester. The physiological significance of this suppressive effect of progesterone was discussed in relation to the vulnerability of pregnant women to vaginal candidiasis.

Animals↗