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Biomedical subjects

C R Yang

Publications and source records attributed to C R Yang.

At least 91 records · Page 5Linked to original sources
PubMed1994

The regulation of insulin-like growth factor-binding protein 1 messenger ribonucleic acid in cultured rat hepatocytes: the roles of glucagon and growth hormone.

In previous studies it was shown that bovine GH (bGH) suppressed and glucagon stimulated the level of 24- and 30- to 34-kilodalton insulin-like growth factor-binding proteins (IGFBPs) in the media of cultured rat hepatocytes. In the present study we have evaluated the regulation of IGFBP-1 gene expression in primary rat hepatocyte cultures. Glucagon produced a dose-dependent stimulation of hepatocyte IGFBP-1 messenger RNA (mRNA), attaining levels 2- to 6-fold greater than control at a glucagon concentration of 100 ng/ml. GH inhibited the accumulation of IGFBP-1 mRNA in a dose-dependent manner producing, 40-70% inhibition at 50 ng/ml. The effect of glucagon was comparable to and additive with dexamethasone (1 microM). The addition of 3-isobutyl-1-methylxanthine (100 microM) and (Bu)2cAMP (100 microM) augmented IGFBP-1 mRNA levels 5- to 6-fold. 4 beta-Phorbol 12 beta-myristate 13 alpha-acetate (300 nM) was found to inhibit IGFBP-1 mRNA levels by 40-50%. The inhibitory effect of bGH on IGFBP-1 mRNA levels was abolished after preincubation with 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (10 microM) for 24 h, whereas glucagon's stimulatory effect was unaffected. The addition of staurosporine (500 nM) and H-7 (1 mM) abolished the inhibitory effect of GH but also significantly inhibited the stimulatory effect of glucagon, a result consistent with these agents acting on both protein kinase C (PKC) and PKA. In the presence of 10 micrograms/ml cycloheximide, IGFBP-1 gene expression was superinduced by bGH, whereas the effect of glucagon was uninfluenced. Thus the inhibitory action of GH involves, in part, the activation of PKC. Glucagon's stimulatory effect seems to involve the activation of PKA. The inhibitory effect of bGH on IGFBP-1 gene expression may require the continuing synthesis of one or more labile protein(s).

1-Methyl-3-isobutylxanthine↗
PubMed1994

Resin glycosides. XXI. Tuguajalapins I-X, the resin glycosides having long-chain fatty acid groups from the root of Merremia hungaiensis.

Ten resin glycosides (jalapins) named tuguajalapins I-X were isolated from the root of Merremia hungaiensis. Their structures have been determined on the bases of chemical and spectral data. Unlike the jalapins so far reported, all of their acyl groups consist of two or three long-chain fatty acids, that is, palmitic, stearic and/or arachidic acids.

Carbohydrate Sequence↗
PubMed1994

Bowel perforation--a fatal complication following renal transplantation: a report of two cases.

From May 1983 to January 1993, 162 patients received renal transplantation at Taichung Veterans General Hospital. Two patients developed bowel perforation after this surgery. One was proved at 21 days and another, at 13 days after renal transplantation. Both patients died as a direct result of the perforation. From a review of literature, the average incidence is 2.7%, and the average mortality rate is 56.5%. Because of this high mortality rate, a high clinical suspicion, prompt and adequate surgical intervention, reduction of immunosuppressive agents and effective antibiotic coverage should contribute to a decline in mortality.

Adult↗
PubMed1994

Alterations in transcription factor binding in radioresistant human melanoma cells after ionizing radiation.

We analyzed alterations in transcription factor binding to specific, known promoter DNA consensus sequences between irradiated and unirradiated radioresistant human melanoma (U1-Mel) cells. The goal of this study was to begin to investigate which transcription factors and DNA-binding sites are responsible for the induction of specific transcripts and proteins after ionizing radiation (Boothman et al., Proc. Natl. Acad. Sci. USA 90, 7200, 1993). Transcription factor binding was observed using DNA band-shift assays and oligonucleotide competition analyses. Confluence-arrested U1-Mel cells were irradiated (4.5 Gy) and harvested at 4 h. Double-stranded oligonucleotides containing known DNA-binding consensus sites for specific transcription factors were used. Increased DNA-binding activity after ionizing radiation was noted with oligonucleotides containing the CREB, NF-kappa B and Sp1 consensus sites. Increased DNA binding activity after ionizing radiation was noted with oligonucleotides containing the CREB, NF-kappa B and Sp1 consensus sites. No changes in protein binding to AP-1, AP-2, AP-3 or CTF/NF1, GRE or Oct-1 consensus sequences were noted. X-ray activation of select transcription factors, which bind certain consensus sites in promoters, may cause specific induction or repression of gene transcription.

Consensus Sequence↗
PubMed1994

Comparison of five modalities in localization of primary aldosteronism.

BACKGROUND: The best response to surgical treatment of primary aldosteronism occurs in patients with an aldosterone-producing adenoma (APA), so pre-operative localization of the lesion is necessary. METHODS: A comparison was made of five localizing modalities-computed tomography (CT) of the adrenal gland, magnetic resonance imaging (MRI), dexamethasone suppression-131I-19-cholesterol adrenal scintiscan (DS, NP-59 adrenal scan), adrenal venography (venography) and adrenal venous sampling for aldosterone content (AVS) in 22 patients (12 women, 10 men) with primary aldosteronism; all had undergone operative confirmation within the past 9 years. The age at diagnosis ranged from 27 to 67 years (mean: 39.7). RESULTS: Unilateral adrenalectomy resulted in normal blood pressure without medication in 63.6% (14/22), and in improvement in 36.4% (8/22). Correct localization of the lesion was obtained in 95% (20/21) by CT, 100% (7/7) by MRI, 80% (12/15) by DS,NP-59 adrenal scan, 100% (6/6) by AVS and 78% (7/9) by venography. CONCLUSIONS: This experience would advocate CT of the adrenals as the initial means of localizing an APA on an outpatient basis because it is comfortable, safe, inexpensive and gives immediate results. The major role of MRI in the evaluation of adrenal adenoma should be complementary to CT. DS, NP-59 adrenal scan can be an adjuvant method for localization if CT scan results are not definitive. Adrenal venous catheterization with blood sampling for aldosterone content could be reserved for patients whose biochemical finging suggests the presence of an APA, and for whom CT or MRI of the adrenals and DS, NP-59 adrenal scan are inconclusive.

Adrenal Glands↗
PubMed1993

Triterpenoid glycosides from Decaisnea fargesii.

Five new triterpenoid glycosides designated decaisosides A-E together with five known ones were isolated from the stems of Decaisnea fargesii. Their structures were established by means of chemical and spectroscopic evidence.

Carbohydrate Sequence↗
PubMed1993

Steroid glycosides from Polygonatum prattii.

Investigation of the roots of Polygonatum prattii afforded three new steroid glycosides, paratiosides A-C, and three new prosapogenins, pratiosides D1, E1 and F1. The latter three, which were obtained from the enzymatic hydrolysis products of a glycoside mixture, are considered to be the corresponding spirostanol glycosides of their proto-type furostanol ones in the plant. The structures of these compounds were established by chemical and spectral methods. It is noted that pratioside C possessing a 3,27-di-O-sugar chain is the first example to be isolated from a natural source.

Carbohydrate Sequence↗
PubMed1993

Depolarizing action of secretory granule protein 7B2 on rat supraoptic neurosecretory neurons.

A novel precursor neuropeptide termed 7B2 is present within specific brain areas, including the hypothalamic magnocellular neurosecretory neurons, and appears to be processed to smaller fragments. In order to determine whether specific C-terminal fragments of 7B2 might exert local effects on neurosecretory cells, we used intracellular current-clamp recordings in supraoptic neurons maintained in superfused hypothalamic explants to evaluate membrane potential and resistance changes in 25 supraoptic nucleus neurons during bolus applications of 7B2 174-186 and two other C-terminal peptide fragments 7B2 156-173 and 7B2 141-150. In 15 supraoptic neurons, only the 7B2 174-186 fragment induced a gradual 2-8 mV membrane depolarization that lasted for 4 to 30 min and was accompanied by 15+/-8% reduction in input resistance. Immunocytochemical identification of the recorded cells revealed that both vasopressin (VP)- and oxytocin (OT)-containing neurons were depolarized by 7B2 174-186. These data suggest that 7B2 174-186 is a biologically active fragment of 7B2 and may regulate the excitability of magnocellular supraoptic nucleus neurons.

Animals↗
PubMed1993

Radiofrequency ablation of left-sided accessory atrioventricular pathways in patients with unusual coronary sinus.

Four patients with left-sided accessory pathways (APs) and unusual coronary sinus (CS) received radiofrequency ablation. Unusual CS included occlusion of CS (patient 1), acute angulation of proximal CS (patients 2 and 3), and narrowing of CS orifice and proximal segment (patient 4). CS catheterization and AP mapping along the CS could not be performed in the four patients. Radiofrequency ablation by left ventricular retrograde technique for the manifest left posteroseptal AP (patient 1), concealed left posterior AP (patient 2), and transseptal left atrial technique for the manifest left posteroseptal AP (patient 3) and manifest left posterior AP (patient 4) were performed successfully without CS catheter guidance. This study suggests that radiofrequency ablation of left-sided AP with unusual CS is feasible by some special techniques.

Adult↗
PubMed1993

Two new steroidal saponins from dried fermented residues of leaf-juices of Agave sisalana forma Dong No. 1.

In a previous paper, we reported the isolation and structure determination of three new steroidal saponins, dongnosides C (3), D (2) and E (1) from the dried fermented residues of leaf-juices of Agave sisalana forma Dong No. 1. In a continuing study on this plant, two additional new major steroidal saponins, named dongnosides B (4) and A (5), were obtained. Their structures were characterized respectively as tigogenin 3-O-alpha-L-rhamonpyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->2)- [beta-D- glucopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->4)-beta-D-galactop yranoside and 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->2)-[beta- D- xylopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->3)]-beta-D- glucopyranosyl-(1-->4)-beta-D-galactopyranoside on the basis of chemical and physicochemical evidence.

Carbohydrate Sequence↗
PubMed1993

Removal of renal cell carcinoma extending into the right atrium using cardiopulmonary bypass, profound hypothermia and circulatory arrest.

A 65-year-old man presented with renal cell carcinoma of the right kidney with a tumor thrombus extending up the vena cava to the right atrium. Cardiopulmonary bypass, profound hypothermia and total circulatory arrest were used to create a bloodless field for excision of the renal cell carcinoma and its tumor thrombus. Acute respiratory failure and deep jaundice developed after the operation and the patient was transferred to the intensive care unit for critical care. After respiratory therapy and nutritional support, the liver function was restored. The endotracheal tube was weaned one month later. The patient has had total resolution of all symptoms and there is no evidence of tumor recurrence of distant metastases after 6 months follow-up.

Aged↗
PubMed1993

[Effect of prolactin on production of acid phosphatase in rat prostatic cells and its mechanism].

The present study revealed the effect of prolactin (PRL) and sex steroid hormones on production of prostatic acid phosphatase (PAP) of the immature rat prostatic epithelial cells in serum-free medium. The results showed that PRL significantly stimulated synthesis and secretion of PAP, but failed to synergize with dihydrotestosterone or estradiol. Dihydrotestosterone or estradiol alone did not promote PAP production. Studies on the mechanism of PRL action indicated that adenyl cyclase was not activated in the action of PRL: Synergistic effect between PRL and prostaglandin E2 and F2 alpha was revealed in the stimulation of PAP production, and the effect of PRL could be blocked by indomethacin (a prostaglandin synthesis inhibitor). In conclusion, PRL directly stimulated PAP production of the cultured rat prostatic epithelial cells in serum-free medium and prostaglandin was involved in PRL action.

Acid Phosphatase↗
PubMed1993

[The clinical effect of slow releasing nicotinate on hyperlipemic impotent patients].

Perycit (Pentaerythriol Tetranicotinate), a slow releasing drug, is one of the drugs used for treating hyperlipemia. Patients with erectile dysfunction (impotence) associated with hyperlipemia increasingly seek help at urological services. This study investigates the clinical effect, both objective and subjective of Perycit on anti-hyperlipemia as well as on impotence. Twenty patients with a more than one year history of impotence with hyperlipemia were enrolled in this randomized, single-blind study. Decrease of total cholesterol, and triglyceride, as well as the increase of high density lipoprotein cholesterol in the study group (Perycit, 500 mg, tid, for 3 months) were significantly different from the pre-treatment period and in the control group (Trental, 100 mg, tid, for 3 months) (p < 0.05 or p < 0.01). Moreover, improvement in sexual function was shown to be better in the study group than in either the pretreatment period and control groups, objectively and subjectively (p < 0.05 or p < 0.01). Tolerable facial flush was found in 3 of these 20 patients, but no major side effects were encountered. In conclusion, this study indicates Perycit is effective for anti-hyperlipemia as well as for aiding improvement of sexual dysfunction. Since it is a slow-releasing preparation, the side effect is minimal. It is recommended for patients with hyperlipemia alone, or those who suffer from combined erectile dysfunction.

Delayed-Action Preparations↗
PubMed1993

[Analgesic effect of tramadol HCL in ESWL].

Since its introduction, extracorporeal shock-wave lithotripsy (ESWL) has become the treatment of choice in patients with urinary calculi. But the pain during ESWL is intolerable for many patients. Tramadol HCL resembles morphine in that it depresses motor and sensory responses of the spinal nociceptive system by a spinal and a supraspinal action. The side effects of tramadol are less than morphine. A prospective study was performed to determine the effect of tramadol in ESWL for the patients with urinary tract calculi. Ninety patients were randomized divided into three groups. Group A 40 patients (male:female = 31:9) received oral tramadol HC1 100 mg; group B 17 patients (male:female = 12.5) received multi-vita; group C 33 patients (male:female = 26:7) received analgesic (contained aspirin 399 mg and codeine phosphate 15 mg). The patients took the drugs 30 minutes before ESWL. The patients with renal calculi > 2 cm in diameter or ureteral calculi > 1 cm in diameter were excluded. The lithotriper used in our hospital is Siemens Lithostar. According to the description of the patients postoperatively, the pain intensity during ESWL was identified with Verbal Scale and Visual Analogue Scale (VAS). The statistical method is one-way ANOVA. Statistical difference is significant when p < 0.05. The mean age of patients group A is 46.5 +/- 17.1, group B 45.5 +/- 14.4, and group C 50.5 +/- 14.6. The mean diameter of urinary calculi of group A is 0.98 +/- 0.41 cm, group B 1.09 +/- 0.33, and group C 1.06 +/- 0.43.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Triterpenoid saponins from Triplostegia grandiflora.

Four new oleanane triterpenoid saponins named triplosides D-G were isolated from the roots of Triplostegia grandiflora. Their structures were elucidated on the basis of chemical degradation and spectral evidence. The saponins investigated were: oleanolic acid 3-O-beta-D-xylopyranosyl(1----4)-beta-D-xylopyranosyl(1----3)-beta-D- xylopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----3)-beta-D- xylopyranosyl(1----3)-alpha-L-rhamnopyranosyl(1----2)-beta-D-xylopyranos ide, oleanolic acid 3-O-beta-D-glucopyranosyl(1----6)-[beta-D- xylopyranosyl(1----4)]-beta-D-glucopyranosyl(1----3)-beta-D- xylopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----3)-beta-D- xylopyranosyl(1----3)-alpha-L-rhamnopyranosyl(1----2)-beta-D-xylopyranos ide, oleanolic acid 3-O-beta-D-xylopyranosyl(1----3)-beta-D-xylopyranosyl(1----4)- alpha-L-rhamnopyranosyl(1----3)-beta-D-xylopyranosyl(1----3)-alpha-L- rhamnopyranosyl(1----2)-beta-D-xylopyranoside and oleanolic acid 3-O-alpha-L-rhamnopyranosyl(1----3)-beta-D-xylopyranosyl(1---3)-alpha-L- rhamnopyranosyl(1----2)-beta-D-xylopyranoside, respectively. All of them have a common aglycone and are monodesmosides.

Carbohydrate Sequence↗
PubMed1992

Oleanane glycosides from Glycyrrhiza yunnanensis roots.

From the roots of Glycyrrhiza yunnanensis, collected in Yunnan, China, six new oleanane-type triterpene glycosides named yunganosides A1, B1, C1, D1, E2 and F2 were isolated together with hypaphorine. The structures of these glycosides were established by spectroscopic and chemical means.

Carbohydrate Sequence↗