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Biomedical subjects

S H Yoon

Publications and source records attributed to S H Yoon.

At least 73 records · Page 4Linked to original sources
PubMed1998

Quality of marital life in Korean spinal cord injured patients.

UNLABELLED: The purposes of this study were to assess the quality of marital life and to investigate the most serious problem in the marital relationships of Korean spinal cord injured patients. 30 spinal cord injured (SCI) couples (SCI husbands and their non-disabled wives) who were married prior to injury and 30 able-bodied (AB) couples participated in a questionnaire study. The quality of marital life was measured with three parameters: marital stability, marital adjustment, and marital satisfaction. The results were as follows: (1) The marriage of chronic SCI couples was not noticeably unstable when compared with that of AB couples; (2) There was no significant difference in dyadic adjustment and marital satisfaction between SCI couples and AB couples; (3) There was no significant difference in marital stability, marital adjustment, and marital satisfaction between SCI husbands and their wives; (4) SCI couples had more cohesive marital relationships and SCI husbands expressed less affection to their wives than AB husbands and (5) Sex was the most serious problem in marriages of SCI couples. IN CONCLUSION: (1) the quality of marital life in chronic SCI couples is not highly different from that of AB couples; (2) There is no significant difference in the quality of marital life between chronic SCI husbands and their non-disabled wives; and (3) It is considered necessary that rehabilitation program for SCI patients should include information on the altered physiology of sexual function of SCI patients and subsequent mutual adaptation to changed sexual function.

Adult↗
PubMed1998

A cytotoxic pennogenin glycoside from Majanthemum dilatatum.

A cytotoxic pennogenin glycoside, pennogenin 3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[ alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside (1) was isolated from the whole herb of Majanthemum dilatatum. Compound 1 showed potent cytotoxic activity against human cancer cell lines.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Fracture originated at the tip of heterotopic ossification of femur by minor external force: report of two cases.

Fracture of femur without evidence of severe osteoporosis rarely occurs as a result of minor external force such as a gentle passive or an active range of motion exercises. We report two cases of femoral shaft fracture occurred at the tip of heterotopic ossification of femur by a minor external force, in which the involved femur shows no evidence of remarkable osteoporosis. The possible mechanism inferred by authors is as follows: 1) heterotopic ossification limits range of motion of the hip joint; 2) a new lever arm is formed at the tip of heterotopic ossification where energy can be concentrated; 3) therefore, fractures develop even by a minor external force. Search for similar cases and further discussions on possible mechanisms and prevention of femoral fractures in patients with heterotopic ossification will be necessary.

Adult↗
PubMed1997

Regulation of protein kinases in steady-state contraction of cat gastric smooth muscle.

Cat gastric smooth muscle strips were used to investigate the involvement of protein kinases in the steady-state contraction induced by 1 microM acetylcholine or 20 mM KCI. The steady-state contraction induced by acetylcholine or KCl was inhibited by EGTA dose dependently. Voltage-dependent Ca2+ channel antagonists dose dependently inhibited the contractions induced by KCI as well as by acetylcholine. Inhibitory effects of voltage-dependent Ca2+ channel antagonists were significantly more prominent on KCI-induced contractions than on acetylcholine-induced contractions. The acetylcholine-induced contraction was dose dependently inhibited by 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8, a blocker of intracellular Ca2+ release), but the KCl-induced contraction was not inhibited at all. Therefore both intracellular Ca2+ release and extracellular Ca2+ influx seem to be necessary for the acetylcholine-induced contraction, but intracellular Ca2+ release is not necessary for the KCl-induced contraction. Protein kinase C inhibitors, 10 microM 1-(5-isoquinolinylsulfonyl)-2-methyl-piperazine 2HCl (H-7) and 1 microM staurosporine, significantly inhibited the contraction induced by acetylcholine or KCl. Calmodulin antagonists, 30 microM trifluoperazine and 50 microM N-(6-aminohexyl)-5-chloro-2-naphthalenesulfonamide HCI (W-7), however, significantly inhibited the contraction induced by acetylcholine but not by KCl. A tyrosine kinase inhibitor, 50 microM genistein, did not affect the acetylcholine-induced contraction but significantly inhibited the KCl-induced contraction. These results strongly suggest that the involvement of protein kinases in regulation of the steady-state contraction may be agonist-dependent.

Acetylcholine↗
PubMed1997

Carcinoma ex pleomorphic adenoma of the palate--a case report.

A case of squamous cell carcinoma ex pleomorphic adenoma in a palate is presented and comments on diagnostic criterias are described. The patient was 36-year-old male presenting with an ovoid elevated palate mass for 6 months. The tumor located in the junctional area of soft and hard palate. The mucosa was diffusely ulcerated and the mass focally tightly adherent to adjacent tissue. The initial cytologic and pathological diagnosis by fine needle aspiration biopsy and open biopsy was benign pleomorphic adenoma. After total removal, histologic examination revealed that tumor was composed partly of benign pleomorphic adenoma and partly of an squamous cell carcinoma component with areas of necrosis and capsular invasion. Immunohistochemical staining in the carcinoma area revealed positive reaction for low and high molecular weight cytokeratin, and epithelial membrane antigen, but negative for desmin, actin, GFAP and S-100 protein. In situ hybridization using biotinylated Epstein-Barr virus probe was done and the neoplastic cells were negative. Our case in an unusual partially encapsulated carcinoma ex pleomorphic adenoma in the palate and is not related in EBV infection.

Adenoma, Pleomorphic↗
PubMed1996

A modified Coomassie blue staining of proteins in polyacrylamide gels with Bismark brown R.

A rapid and sensitive protein staining method employing a mixed dye technique has been developed. Solutions of Coomassie brilliant blue R-250 (CB, 0.2%) and Bismark brown R (BBR, 0.05%) were mixed in the volume ratio of 1:0.75 for staining (final molar ratio, 4.5:1). In this staining, BBR inhibits the binding of CB to gel matrix by forming ion-pairing complex with excess CB; therefore, it reduces staining/destaining times and also enhances the staining effect of CB on protein band. As a result, the mixed dye staining enables complete staining/destaining within 20/25 min and detection of up to 25 ng of bovine serum albumin.

Animals↗
PubMed1996

Stimulatory role of the dorsal motor nucleus of the vagus in gastrointestinal motility through myoelectromechanical coordination in cats.

This study was undertaken to investigate the effect of stimulation of the dorsal motor nucleus of the vagus (DMV) on myoelectric activity and motility of the gastric antrum and duodenum in normal and in vagotomized cats. 37 cats were starved for 24 h and then anesthetized with alpha-chloralose (70-80 mg/kg, iv). Electrical stimulation (0.1 mA, 0.2 ms, 50 Hz) of the left DMV was performed through a stereotaxically inserted electrode in 19 of the cats. The remaining 18 cats were injected in the left DMV with a glutamate solution (1 M, 200 nl) through an inserted 3-barreled micropipette. The myoelectric activity (slow wave) and the motility of the gastric antrum (2 cm proximal to the pylorus) and duodenum (3 cm distal to the pylorus) were measured using serosal bipolar electrodes and intraluminal balloons. Both the electrical and the glutamate stimulations of the DMV markedly increased the occurrence of spike potentials on the antral and duodenal myoelectric activity; however, the stimulations significantly decreased the frequency of the antral slow wave. The stimulations also produced increases in the motility of the antrum and duodenum which corresponded to the changes in the myoelectric activity. All the changes in the myoelectric activity and the motility were not observed after the ipsilateral vagotomy. Thus, these results strongly suggest that the dorsal motor nucleus of the vagus has a stimulatory influence on antral and duodenal motility through myoelectromechanical coordination via the vagus nerve in cats.

Animals↗
PubMed1995

Applications of MTT assay to primary cultured rat hepatocytes.

We investigated the optimal conditions for the application of the MTT assay to determine the viability of cell in primary cultures of rat hepatocytes. The optimal conditions were found to be: inoculation at cell density of 1.31 x 10(5) cells/cm2; concentration of 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) 0.12 mM; and MTT incorporation time, 2 h or more. We also found that insulin and glucocorticoid, which are usually added to the medium to maintain cell function, had no effect on the viability of the primary cultures of rat hepatocytes.

Animals↗
PubMed1994

Stimulatory effects of the central amygdaloid nucleus on pancreatic exocrine secretion in rats.

The effects of electrical stimulation of the central (CE) and basolateral (BL) amygdaloid nuclei on pancreatic exocrine secretion were tested in urethane-anesthetized rats. Electrical stimulation (0.1 mA, 1 ms, 40 Hz) of the CE significantly increased basal and hormone (secretin+cholecystokinin-8)-infused pancreatic exocrine secretion. These increases in pancreatic secretion were abolished by bilateral vagotomy. Electrical stimulation of the BL had no significant effect on basal and hormone-infused secretion. We conclude that the CE plays a stimulatory role in pancreatic exocrine secretion via the vagus nerve but the BL does not affect pancreatic secretion.

Amygdala↗
PubMed1994

Effect of medial amygdaloid stimulation on pancreatic exocrine secretion in anesthetized rats.

Effects of medial amygdaloid stimulation on pancreatic exocrine secretion were investigated in anesthetized rats with pyloric ligation. During intraduodenal 0.01 N HCl perfusion, the electrical stimulation of the medial amygdaloid nucleus augmented significantly the HCl-induced pancreatic secretion of water and bicarbonate output. The duodenal acidification significantly increased secretin concentration in plasma. The effects of medial amygdaloid stimulation were also tested in the rats that received a small dose of porcine secretin. Although the amount of secretin infused was not enough to increase the pancreatic exocrine secretion, the stimulation of the medial amygdaloid nucleus significantly increased flow and bicarbonate output. The augmented pancreatic secretory responses to electrical stimulation of the medial amygdaloid nucleus were abolished by bilateral truncal vagotomy. However, the medial amygdaloid stimulation was not effective in stimulating pancreatic secretion in the rats perfused with isotonic saline. From these results, it is suggested that the medial amygdaloid nucleus plays a stimulatory role in pancreatic exocrine secretion via vagus nerves and that a certain level of plasma secretin is needed for the medial amygdaloid stimulation to be effective.

Amygdala↗
PubMed1993

H1 receptor mediates inositol phosphates response to histamine in gastric smooth muscle of guinea pigs.

The effect of histamine on [3H]-inositol phosphates (IPs) formation was investigated with [3H]-inositol-labeled gastric smooth-muscle cells in guinea pigs. Histamine (10(-5) M) increased the formation of [3H]-IPs in the muscle cells. The increase was significantly inhibited by pyrilamine (10(-5) M) but not by cimetidine (10(-5) M). The contractile response to histamine was also completely inhibited by pyrilamine but not by cimetidine. Phorbol ester 12-myristate 13-acetate (10 microM) significantly inhibited histamine-stimulated [3H]-IPs formation by 56%, whereas forskolin (10 microM) decreased it by 18%. This study demonstrates that the response of [3H]-IPs formation and contraction to histamine is mediated through H1 receptor, and the formation of [3H]-IPs is negatively regulated by protein kinase C in gastric smooth muscle of guinea pigs.

Animals↗
PubMed1993

Synthesis and in vitro dopaminergic activity of (2-aminoethyl)-1-hydroxy-2-pyridone type dopamine analogs.

Two isoteric/isoelectronic dopamine analogs based of (2'-aminoethyl)-1-hydroxy-2-pyridone without having the COMT vulnerable m-hydroxy group were synthesized via ten synthetic steps. Their dopaminergic activities were evaluated by measuring the inhibitory effects of prolactin secretion from the anterior pituitary in rats. The compounds 1 and 2 caused a reduction of prolactin secretion at the 10(-6) M concentration. Semiempirical MO calculations (at the AM-1 level) were performed on 1 and 2 in order to understand the structural and electronic features as compared to dopamine.

Animals↗
PubMed1991

Molecular defect of truncated beta-spectrin associated with hereditary elliptocytosis. Beta-spectrin Gottingen.

A large German family with autosomal dominantly inherited elliptocytosis, associated with truncated beta-spectrin missing the phosphorylated C-terminal peptide, has been described (Eber, S.W., Morris, S. A., Schroeter, W., and Gratzer, W. B. (1988) J. Clin. Invest. 81, 523-530). We have attempted to delineate the molecular defect of this abnormality at the gene level. Southern blot analyses revealed no evidence of a partial gene deletion or rearrangement. We used polymerase chain reaction (PCR) and amplified several relevant portions of the beta-spectrin gene, using genomic DNA from two different heterozygous patients. No abnormality was found in the last four exons of the beta-spectrin gene produced by PCR. Examination of the introns connecting the last four exons revealed a T to A substitution in the 5' splice site following the exon X in four of eight clones prepared from two affected individuals, but not from a normal subject of this family. To examine the effect of the T to A substitution in these patients, we made cDNA from the reticulocyte mRNA of the patient and examined its composition by PCR. Two distinct PCR fragments produced from the patient's beta-spectrin cDNA were found. One matched the predicted size for normal spectrin, while the other was 197 base pairs shorter. The mutant cDNA sequence revealed that the entire exon preceding the T to A substitution was spliced out, while the two terminal exons were preserved. The deletion of this exon resulted in a frameshift giving a different terminal amino acid (serine instead of leucine) as well as a new termination codon causing a deletion of 129 amino acids including potentially phosphorylated residues.

Base Sequence↗
PubMed1991

Molecular basis of spectrin and ankyrin deficiencies in severe hereditary spherocytosis: evidence implicating a primary defect of ankyrin.

While varying degrees of spectrin deficiency have been found in the majority of patients with hereditary spherocytosis (HS), a combined severe deficiency of both spectrin and the spectrin-binding protein, ankyrin, has been reported only in two patients with severe HS. To elucidate the molecular basis of these protein deficiencies, we have studied the synthesis, assembly, and the mRNA levels of spectrin and ankyrin in peripheral blood reticulocytes in one of the previously reported probands. Pulse-labeling studies showed that in HS reticulocytes, the synthesis of alpha-spectrin was comparable with control reticulocytes while that of beta-spectrin was increased about fourfold, presumably reflecting increased erythropoietic drive. On the HS reticulocyte membrane, the amount of newly assembled spectrin was reduced to about half of the control values, presumably reflecting a decrease in the synthesis of the spectrin binding protein, ankyrin: the ankyrin synthesis was nearly absent in the cytosol and the amounts of membrane-associated ankyrin were reduced to about half of the normal values. The changes in the amounts of spectrin and ankyrin mRNAs quantitated by slot blot and Northern blot analyses were comparable with changes in the synthesis of these proteins: The alpha spectrin mRNA was within a control range and the beta-spectrin mRNA was slightly increased, while the amounts of ankyrin mRNA were reduced to about 50% of control values. We conclude that the primary defect underlying the combined spectrin and ankyrin deficiency is a deficiency of ankyrin mRNA leading to a reduced synthesis of ankyrin which, in turn, underlies the decreased assembly of spectrin on the membrane.

Adult↗
PubMed1990

Electrical stimulation of the medial amygdala facilitates gastric acid secretion in conscious rats.

One hundred and twenty-seven conscious rats prepared with chronic gastric fistula were studied to investigate the effect of stimulation of the medial amygdala on gastric acid secretion. Gastric acid output was significantly increased by electrical stimulation of the medial amygdala in normal rats and the increase in acid secretion was completely abolished by vagotomy. Vagotomized rats, with or without amygdaloid stimulation, showed comparable levels of gastric acid output which were significantly lower than in controls. These results indicate that the amygdala effect on gastric acid secretion is carried via the vagus nerve. Subcutaneous injections of high doses of histamine increased gastric acid secretion which was further increased by amygdaloid stimulation. Plasma levels of gastrin were not significantly changed by stimulation of the medial amygdala with or without vagotomy. From the above results, we concluded that in conscious rats the medial amygdala plays a significant role in stimulating gastric acid secretion, the vagus nerve is involved in this process, but it is not mediated by release of either histamine or gastrin.

Amygdala↗
PubMed1990

Identification of an unusual deletion within homologous repeats of human reticulocyte beta-spectrin and probable peptide polymorphism.

We screened two different human reticulocyte cDNA libraries with beta-spectrin(beta Sp)-specific polyclonal antibodies and with our original radiolabeled human BSP cDNA probe (encoding beta Sp). Of the 20 independent clones, the largest had about a 2.5-kb insert corresponding to the deduced amino acid (aa) sequence of the beta-7 to beta-14 repetitive segments. Among these segments, segment 12 was 7 aa shorter than the other repetitive segments. We showed that this truncation was not a result of (i) cloning artifact, (ii) alternate splicing, or (iii) common genomic polymorphism by additional examination of 14 individual human chromosomes. Recently, another laboratory described the BSP nucleotide (nt) sequence overlapping partially with our sequence. These overlapping sequences were homologous with the exception of two nt differences at the positions 1342 and 1514. The discrepancy at nt 1342 changes the His to Arg. This newly derived probe has been used to find an additional example of BSP restriction fragment length polymorphism.

Amino Acid Sequence↗
PubMed1990

Patterns of spectrin transcripts in erythroid and non-erythroid cells.

Spectrin is the major protein of the membrane erythrocyte skeleton. More recently, homologous but non-identical spectrins (fodrins) were also found in various non-erythroid tissues. Spectrin mRNA in erythroid and various non-erythroid cells was examined by direct hybridization with human alpha-spectrin, beta-spectrin (erythroid spectrins), and alpha-fodrin (non-erythroid spectrin) cDNA probes. Northern blot analysis of poly (A)+ RNA revealed a distinct pattern of expression in erythroid vs. non-erythroid cells. Erythroid cells from early erythroblasts to reticulocyte stage expressed two mRNA species of beta-spectrin, whereas they expressed only a single species of alpha-spectrin, and no alpha-fodrin mRNA. In contrast, non-erythroid cells (platelets, myeloid cells, liver, muscle, heart, cerebellum, and eye lens) expressed either no alpha-spectrin mRNA or a different molecular weight transcript(s) of this gene, and a single species of alpha-fodrin mRNA. Additionally, they also expressed from none to multiple species of beta-spectrin, and these were of different molecular size(s) from that found in erythroid cells (with the exception of platelets). Transcripts of non-erythroid spectrin, alpha-fodrin, were found as a single copy only in non-erythroid tissues. Human and murine erythroleukemia cells expressed both erythroid spectrin transcripts in addition to alpha-fodrin and raise the possibility that erythroid progenitors may have the potential to express both erythroid and non-erythroid species. These data indicated that several mRNA species of beta-spectrin could be detected in both erythroid and some non-erythroid cells. Whether multiple spectrin peptides could also be found with functional heterogeneity is unclear. However, in each case, the pattern combination observed appeared to be tissue-specific.

Blotting, Northern↗