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Biomedical subjects

N Shimoda

Publications and source records attributed to N Shimoda.

At least 55 records · Page 3Linked to original sources
PubMed1995

Evaluation of liposomal erythropoietin prepared with reverse-phase evaporation vesicle method by subcutaneous administration in rats.

We encapsulated erythropoietin (Epo) in dipalmitoylphosphatidylcholine (DPPC) liposomes with soybean-derived sterols (SS-liposomes) and its glucoside (SG-liposomes) by reverse-phase evaporation vesicle method, and evaluated them by subcutaneous administration in rats. With 4 min of sonication, the damage to Epo activity was observed mainly in the non-encapsulated Epo in the liposomes. This study indicated that the bilayer of liposomes had the ability to protect the Epo activity, by reducing the aggregation that was caused by interaction between Epo molecules. The SG-liposomes had a higher retention of the Epo activity the SS-liposomes. 25.3% or 33.6% of activity was retained by SS-liposomes under the conditions of 4 min or 1 min of sonication, while 53.3% or 58.3% of the activity was retained by SG-liposomes under the same conditions. Shorter sonication was available to minimize the loss of the Epo activity. Epo in SG-liposomes appeared to increase the activity.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

Discharge properties of medullary reticulospinal neurons during postural changes induced by intrapontine injections of carbachol, atropine and serotonin, and their functional linkages to hindlimb motoneurons in cats.

The present study was aimed at elucidating the pontomedullary and spinal cord mechanisms of postural atonia induced by microinjection of carbachol and restored by microinjections of serotonin or atropine sulfate into the nucleus reticularis pontis oralis (NRPo). Medullary reticulospinal neurons (n = 132) antidromically activated by stimulating the L1 spinal cord segment were recorded extracellularly. Seventy-eight of them were orthodromically activated with mono- or disynaptic latencies by stimulating the NRPo area at the site where carbachol injections effectively induced postural atonia. Most of these reticulospinal neurons (71 of 78) were located in the nucleus reticularis gigantocellularis (NRGc). Following carbachol injection into the NRPo, discharge rates of the NRGc reticulospinal neurons (29 of 34) increased, while the activity of soleus muscles decreased bilaterally. Serotonin or atropine injections into the same NRPo area resulted in a decrease in the discharge rates of the reticulospinal neurons with a concomitant increase in the levels of hindlimb muscle tone. Membrane potentials of hindlimb extensor and flexor alpha motoneurons (MNs) were hyperpolarized and depolarized by carbachol and serotonin or atropine injections, respectively. In all pairs of reticulospinal neurons and MNs (n = 11), there was a high correlation between the increase in the discharge rates and the degree of membrane hyperpolarization of the MNs. Spike-triggered averaging during carbachol-induced atonia revealed that inhibitory postsynaptic potentials (IPSPs) were evoked in 15 MNs by the discharges of nine reticulospinal neurons. Four of them evoked IPSPs in more than one MN. The mean segmental delay and the mean time to the peak of IPSPs were 1.6 ms and 2.0 ms, respectively. Axonal trajectories of reticulospinal neurons (n = 6), which evoked IPSPs in MNs, were investigated in the lumbosacral segments (L1-S1) by antidromic threshold mapping. The stem axons descended through the ventral (n = 2) and ventrolateral (n = 4) funiculi in the lumbar segments. All axons projected their collaterals to the intermediate region (laminae V, VI) and ventromedial part (laminae VII, VIII) of the gray matter. All these results suggest that the reticulospinal pathway originating from the NRGc is involved in postural atonia induced by pontine microinjection of carbachol, and that the pathway is inactivated during the postural restoration induced by subsequent injections of serotonin or atropine. It is further suggested that the pontine inhibitory effect is mediated via segmental inhibitory interneurons projecting to MNs.

Action Potentials↗
PubMed1994

[Roles of sacral spinal alpha-adrenoceptive mechanism in micturition reflex in the decerebrate dog].

Roles of sacral spinal alpha-adrenoceptive mechanism in micturition reflex were examined in 19 decerebrate dogs. Alpha 1- and alpha 2-adrenergic agents were injected into the sacral subarachnoidal space. Micturition reflex was evoked by filling the bladder before and after the drug injection. The intravesical pressure (IVP), the intraurethral pressure (IUP) and the electromyogram (EMG) of the external urethral sphincter muscle (EUS) were recorded simultaneously. The bladder volume, the IVP at the threshold of micturition reflex, the minimum IUP, the maximum IUP and the mean IUP were measured during collecting phase. The maximum IVP and the minimum IUP were measured during contraction phase. The effects of adrenergic agents on these measured parameters were analyzed using Wilcoxon's test. The changes of the EUS-EMG were also studied. Intrathecal injection of phenylephrine, an alpha 1-agonist, significantly increased the bladder volume and the mean IUP during the collecting phase, and tended to enhance the EUS-EMG during both phases. Intrathecal injection of prazosin, an alpha 1-antagonist, tended to diminish the EUS-EMG during both phases. Intrathecal injection of clonidine, an alpha 2-agonist, significantly decreased the minimum IUP, the maximum IUP and the mean IUP during the collecting phase, and tended to diminish the EUS-EMG during both phases. Intrathecal injection of yohimbine, an alpha 2-antagonist, decreased the maximum IVP during the collecting phase significantly. These results suggest that the sacral alpha-adrenoceptive mechanism mediates elevation of the threshold of micturition reflex and facilitation of the EUS activity via alpha 1-receptor, while facilitation of the bladder contractility and inhibition of the EUS activity via alpha 2-receptor.

Adrenergic alpha-Agonists↗
PubMed1993

Genetic evidence for an interaction between the VirA sensor protein and the ChvE sugar-binding protein of Agrobacterium.

Most vir genes of Agrobacterium, which are required for tumorigenicity of the bacterium, are expressed in response to plant phenolics. The induction of vir is markedly enhanced by specific monosaccharides. Signals generated by both types of compound are transduced into Agrobacterium cells via the functions of the VirA membrane-bound sensor protein. A putative sugar-binding protein, known as ChvE, also functions at a step of the enhancement of vir induction by monosaccharides. To investigate the signal pathway of the enhancement by the sugars, we first isolated a virA mutant of Agrobacterium with a base substitution mutation that caused a single amino acid change in the periplasmic domain. The mutant exhibited no enhancement of vir induction by sugar and had severely attenuated tumorigenicity on Kalanchoe leaves. We then isolated two chvE mutants that restored sugar enhancement on the background of this virA mutation. One chvE mutant, which exhibited a higher level of sugar enhancement, restored the tumorigenicity of the virA mutant. Wild-type and suppressor ChvE proteins were localized in the periplasmic space. These results provide genetic evidence for the physical interaction between VirA and ChvE proteins in the periplasmic space of Agrobacterium, which enhances the cytoplasmic signal generated by phenolics. We also discuss the molecular architecture of the operon to which the chvE gene belongs.

Amino Acid Sequence↗
PubMed1993

[Pregnancy obtained by in vitro fertilization (IVF) with epididymal spermatozoa in obstructive azoospermia: report of two cases].

Epididymal spermatozoa aspiration was performed in two cases of obstructive azoospermia. After the procedure, in both cases, the patient's wives obtained twin pregnancies by this method in conjunction with in vitro fertilization (IVF) and embryo transfer (ET). The patient's wife in one case had a normal delivery. The patient's wife in the other case, however, aborted artificially because she had cerebral infarction. Epididymal spermatozoa aspiration proved efficacious for male sterility in cases of obstructive azoospermia.

Adult↗
PubMed1992

The changes in the activity of pudendal motoneurons in relation to reflex micturition evoked in decerebrate cats.

Reflex micturition was evoked in both non-immobilized (n = 5) and immobilized (n = 5) decerebrate cats by filling the bladder with physiological saline. Intracellular recordings were made from pudendal motoneurons (PU-MNs; n = 14) throughout the periods of before, during and after reflex micturition. The changes in the activity of PU-MNs were correlated with those in the intravesical pressure. Our results support the proposition that coordination of the sphincters and the detrusors is established by a gating mechanism, which is activated by the supraspinal source such as the pontine micturition center.

Animals↗
PubMed1992

Biosynthesis of the blood group P antigen-like GalNAc beta 1-->3Gal beta 1-->4GlcNAc/Glc structure: a novel N-acetylgalactosaminyltransferase in human blood plasma.

Human blood group O plasma was found to contain an N-acetylgalactosaminyltransferase which catalyzes the transfer of N-acetylgalactosamine from UDP-GalNAc to Gal beta 1-->4Glc, Gal beta 1-->4GlcNAc, asialo-alpha 1-acid glycoprotein, and Gal beta 1-->4GlcNAc beta 1-->3Gal beta 1-->4Glc-ceramide, but not to Gal beta 1-->3GlcNAc. The enzyme required Mn2+ for its activity and showed a pH optimum at 7.0. The reaction products were readily hydrolyzed by beta-N-acetylhexosaminidase and released N-acetylgalactosamine. Apparent Km values for UDP-GalNAc, Mn2+, lactose, N-acetyllactosamine, and terminal N-acetyllactosaminyl residues of asialo-alpha 1-acid glycoprotein were 0.64, 0.28, 69, 20, and 1.5 mM, respectively. Studies on acceptor substrate competition indicated that all the acceptor substrates mentioned above compete for one enzyme, whereas the enzyme can be distinguished from an NeuAc alpha 2-->3Gal beta-1,4-N-acetylgalactosaminyltransferase, which also occurs in human plasma. The methylation study of the product formed by the transfer of N-acetylgalactosamine to lactose revealed that N-acetylgalactosamine had been transferred to the carbon-3 position of the beta-galactosyl residue. Although the GalNAc beta 1-->3Gal structure is known to have the blood group P antigen activity, human plasma showed no detectable activity of Gal alpha 1-->4Gal beta-1,3-N-acetylgalactosaminyltransferase, which is involved in the synthesis of the major P antigen-active glycolipid, GalNAc beta 1-->3Gal alpha 1-->4Gal beta 1-->4Glc-ceramide. Hence, the GalNAc beta 1-->3Gal beta 1-->4GlcNAc/Glc structure is synthesized by the novel Gal beta 1-->4GlcNAc/Glc beta-1,3-N-acetylgalactosaminyltransferase.

Acetylgalactosamine↗
PubMed1992

Cutaneous leiomyosarcoma.

A child's head-sized tumor on the upper back developed in a 43-year-old man. In spite of an extensive operation for the tumor, he died of multiple metastasis 15 months after the operation. Histologically, tumor cells proliferated throughout the dermal and subcutaneous regions, and a boxed-in appearance was noted with silver staining. Because electron microscopic observations strongly suggested a smooth muscle origin, we diagnosed this case as cutaneous and subcutaneous leiomyosarcoma.

Adult↗
PubMed1992

[Effect of terazosin on lower urinary tract function in the male decerebrate dog].

The effect of terazosin on the lower urinary tract function was studied by combined recording of bladder and urethral pressures and external sphincter electromyogram in 8 male decerebrate dogs. Reflex micturitions were induced by bladder filling before and after terazosin. The statistical analysis was carried out on the urodynamic parameters. During the collecting phase, terazosin at doses of 10, 30 and 100 micrograms/kg produced a significant decrease in maximum urethral pressure in the dose dependent manner. Threshold pressure was significantly shown to decrease at doses of 30 and 100 micrograms/kg. In the urodynamic parameters of the emptying phase there was a significant decrease in maximum contraction pressure at 10 and 30 micrograms/kg, and in voided volume at 100 micrograms/kg. Terazosin seems to facilitate an initiation of the bladder contraction with a decrease in threshold pressure. In concludes that alpha 1 adrenergic activity seems to take an important role for the maintenance of the urethral pressure and to control the initiation of bladder contraction in modulation with threshold pressure.

Animals↗
PubMed1992

Effect of methylene blue on the vesicourethral function in the rats.

The bladder and urethral activities during the rhythmic bladder contractions were evaluated before and after the intraarterial administration of methylene blue, which prevents the activation of soluble guanylate cyclase. The methylene blue produced an increase in the bladder activity and a decrease in the urethral smooth muscle relaxant response induced with bladder contraction. The L-arginine/nitric oxide pathway seems to modulate the vesicourethral function.

Anesthesia↗
PubMed1992

[Vesical ultrasonography and internal examination of female patients with urethral syndrome].

Transabdominal ultrasonography of the bladder and internal examination were performed in 80 female patients without pyuria. They were divided into 3 groups: urethral syndrome with trigonitis (49 cases), asymptomatic trigonitis (16 cases) and normal bladder (15 cases) by cystoscopy. Ultrasonography of trigonitis with or without symptoms showed focal dilation of the submucosal low echo zone and mucosal irregularity around the bladder neck. On the sagittal view, the thicknesses from the surface of mucosa to that of muscle layer within 2 cm from the bladder neck were 4 +/- 1 mm (mean +/- standard deviation) in the group with urethral syndrome and in that with asymptomatic trigonitis, and 3 +/- 1 mm in the normal bladder group. Mucosa of the trigonitis with or without symptom is patients with significantly thicker than that of those with normal bladder (p less than 0.01). On internal examination, tenderness at the upper frontal wall of the vagina was present in 10 of 11 cases (91%) with urethral syndrome, in 2 of 8 cases (25%) with asymptomatic trigonitis and in one of 9 cases (11%) with normal bladder. There was a significant difference (p less than 0.005) between the degree of inflammation and the number of cases with tenderness at the frontal wall of the vagina. From these results, transabdominal ultrasonographic measurement of mucosal thickness around the bladder neck and internal examination for tenderness at the frontal wall of vagina are thought to be useful methods for diagnosis and follow-up of urethral syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Effect of YM-12617 (amsulosin hydrochloride) on lower urinary tract function in the female decerebrate dog].

The effect of YM-12617 on the lower urinary tract function was studied by combined recording of cystometry and external sphincter electromyogram (EMG) in 11 female decerebrate dogs. Reflex micturitions were induced by bladder filling before and after YM-12617 administration. Statistical analysis was carried out on the urodynamic parameters. YM-12617 in a dose of 10 micrograms/kg significantly decreased micturition threshold pressure during the collecting phase. In the urodynamic parameters of the emptying phase there was a significant decrease in contraction pressure at 10 and 30 micrograms/kg.

Adrenergic alpha-Antagonists↗
PubMed1992

Use of synthetic H disaccharides as acceptors for detecting activities of UDP-GalNAc:Fuc alpha 1-->2Gal beta-R alpha 1-->3-N-acetylgalactosaminyltransferase in plasma samples from blood group A subgroups.

Concentrations of blood group A-specified alpha(1-->3)-N-acetylgalactosaminyltransferase (A enzyme) were measured in human plasma of blood groups A1, A2, and A3 by using chemically synthesized H disaccharides and H type 1 and type 2 trisaccharides attached to hydrophobic aglycones as acceptors. When the trisaccharides were used as acceptors, enzyme activities were reduced in samples from A2 and A3. However, the H disaccharides were shown to be good acceptors even for enzymes from A2 and A3, and no significant difference in enzyme concentration was detected in any of the plasma tested.

ABO Blood-Group System↗
PubMed1992

[Comparative study on nephrotoxicity of ionic and non-ionic contrast agents for drip infused urography].

The effects on renal function of an ionic and hyperosmolaric contrast agent (diatrizoate) and a non-ionic and slightly hypertonic agent (iohexol) for drip infused urography were compared on 60 patients with normal renal function. Urine samples were collected before and 30 minutes after drip infusion of contrast agent, and analyzed for albumin (ALB), gamma-glutamyl transpeptidase (gamma-GTP), N-acetyl-beta-glucosaminidase (NAG), beta 2 microglobulin (beta 2MG) and creatinine (CRE). The urinary excretion of proteins and enzymes was compared with urinary CRE. gamma-GTP, NAG and beta 2MG increased significantly after infusion of diatrizoate. gamma-GTP and beta 2MG increased significantly after infusion of iohexol. Excretion of ALB, gamma-GTP, NAG and beta 2MG was significantly higher after infusion of diatrizoate than after iohexol. The urinary concentration of CRE was significantly lower after infusion of diatrizoate than after iohexol. The degree of renal damage after urography was no related to the appearance of allergy to the contrast agent or age of patient. Therefore, the non-ionic and slightly hyperosmolaric iohexol may be less toxic to the kidneys than the ionic and hypertonic diatrizoate. This nephrotoxicity after drip infused urography is thought to be related mainly to the osmolarity of contrast agent.

Adult↗
PubMed1992

[Effects of Tsumura Chorei-to and Tsumura Chorei-to-go-shimotsu-to on patients with urethral syndrome].

Tsumura Chorei-to or Tsumura Chorei-to-go-shimotsu-to, was administered to 71 female patients with urethral syndrome 2.5 g three times a day for four weeks. Total efficacy rate of Tsumura Chorei-to in 34 cases was 71%. Tsumura Chorei-to was effective against pollakisuria, miction pain or discomfort, sense of residual urine and lower abdominal discomfort. Total efficacy rate of Tsumura Chorei-to-go-shimotsu-to in 37 cases was 57%. Tsumura Chorei-to-go-shimotsu-to was effective against dysuria, sense of residual urine and lower abdominal discomfort. Uutoward effect rates of Tsumura Chorei-to and Tsumura Chorei-to-go-shimotsu-to were 6% and 14%, respectively. Many of the untoward effects of these two drugs were epigastral discomfort. These two drugs are thought to be effective on patients with urethral syndrome.

Adult↗
PubMed1991

Contact sensitivity to mercuric chloride is associated with I-A region in mice.

Genetic control of contact sensitivity to mercuric chloride antigen was studied using various strains on inbred mice. Mice with class II Ab,d,f,s haplotypes showed a high magnitude of response, whereas those with class II Ak,q were low responders. These results indicate that mercuric chloride contact sensitivity may be influenced by the I-A region of H-2. Transfer experiments revealed that these responses might be mediated by L3T4+, Lyt-2- T cells. However Lyt-2+ T cells do not suppress the DTH response.

Animals↗
PubMed1991

A case of xeroderma pigmentosum group D determined by photobiological study.

A case of xeroderma pigmentosum group D in 36-year-old woman (XP85TO) is reported. The patient had severe photosensitivity from age 4, and developed multiple basal cell epitheliomas and solar keratoses but exhibited no apparent neurological defects. A skin phototest by monochromatic ultraviolet light revealed a delayed peak of erythema 48 h after irradiation and lowered minimal erythemal doses. Unscheduled DNA synthesis induced in XP85TO cells was 36.0% in dermal fibroblasts and 32.6% in epidermal keratinocytes compared with normal cells. The XP85TO cells were sensitive to ultraviolet killing (n = 1.0, D0 = 0.80 J/m2). In complementation analysis, XP85TO cells did not complement with xeroderma pigmentosum group D cells. These results indicate that patient XP85TO had xeroderma pigmentosum group D. The Japanese group D patients including XP85TO case showed delayed onset of skin malignant tumors and neurological abnormalities, compared with the group D patients in Europe and the United States. These findings suggest a possible ethnic variation of the clinical phenotype, despite the similar repair defect and ultraviolet hyperssensitivity.

Adult↗