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C R Yang

Publications and source records attributed to C R Yang.

At least 145 records · Page 8Linked to original sources
PubMed1989

Comparison of penile vascular effect induced by intracavernous injection of papaverine and prostaglandin E1.

An intracavernous injection with papaverine or prostaglandin E1 (PGE1) combined with duplex ultrasonography is an objective technique to conduct a penile blood flow study (PBFS). Three hundred patients with impotence underwent papaverine (9-60 mg) induced PBFS at the University of California School of Medicine, San Francisco (UCSF), U.S.A. and another 80 patients with impotence received PGE1-induced (20 micrograms) PBFS at Veterans General Hospital-Taichung (VGH-TC), R.O.C. Preliminary evaluation of age, duration of disease and pre-injection diameter of cavernous arteries disclosed no significant difference in these 2 series. It was interesting to find that almost all parameters of vascular response to pavaverine vs PGE1 differed significantly, such as onset of response (6.5 +/- 6.5 vs 11.7 +/- 6.4 min, slower in the PGE1 group, p less than 0.001); post-injection diameter of cavernous arteries (right: 0.73 +/- 0.20 vs 0.79 +/- 0.18 mm, p = 0.03; left: 0.74 +/- 0.20 vs 0.82 +/- 0.21 mm, p = 0.005); diametral increment of cavernous arteries (right: 0.23 +/- 0.17 vs 0.33 +/- 0.17 mm, p less than 0.001; left: 0.24 +/- 0.17 vs 0.36 +/- 0.19 mm, p less than 0.001) and peak velocity (right: 27.5 +/- 16.1 vs 42.0 +/- 20.1 cm/sec, p less than 0.001; left: 28.9 +/- 15.9 vs 39.7 +/- 17.9 cm/sec, p less than 0.001). The side effects, primarily injection pain (23.8%, 19/80) in the PGE1 group and dizziness (3.0%, 9/300) in the papaverine group, were minor in these 2 series. Prolonged erection was not encountered in either series; however, immediate treatment was performed if a papaverine-induced erection lasted over 60 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Transrectal sonography of the prostate and seminal vesicles on patients with hemospermia.

Morphological change of the seminal tract of patients with hemospermia was determined by means of transrectal sonography on 38 patients. Twenty-seven (71%) had positive sonographic findings, including 20 prostatitis and/or seminal vesiculitis, three benigh prostatic hypertrophy, three prostate calculi and one seminal vesicle stone. Simultaneous bacteriologic study revealed positive cultures on 11 patients; 9 of whom (81%) had morphologic appearance on transrectal sonography suggesting inflammatory origin. Our experience indicates that transrectal sonography is capable of surveying the histopathologic change of the prostate and seminal vesicles, and is therefore effective in studying patients with organic hemospermia.

Adult↗
PubMed1989

Primary carcinoma of the bulbo-membranous urethra.

Twenty-four cases of primary carcinoma of the bulbo-membranous were reviewed. While half of them had history of gonorrhea or urethral stricture, most of patients initially presenting with high grade (58%) and high stage (91%) contributed to the poor prognosis of the patients studied. Some patients with clinical localized disease were cured by radical cysto-prostatectomy, penectomy with or without emasculation and resection of inferior pubic rami following with or without preoperative irradiation. The result of radical irradiation is uniformly poor. Based on the small number of cases in this report, we could not conclude that preoperative irradiation would improve the results of excision; however, the recent introduction of neoadjnvant chemotherapy for patients with transitional cell carcinoma warrants further investigation.

Adult↗
PubMed1988

c-erbA protooncogenes mediate thyroid hormone-dependent and independent regulation of the rat growth hormone and prolactin genes.

Regulation of gene expression by the thyroid hormones is thought to be mediated by a nuclear-associated receptor found in a wide variety of cells and tissues. Cellular homologues of the avian erythroblastosis virus oncogene, v-erbA, encode proteins which bind thyroid hormone with similar affinities as thyroid hormone receptors. However, it has not been shown that any of the c-erbA proteins can function as receptor and modulate thyroid hormone responsive genes. In this study, using transient expression of chimeric reporter constructs, we document that the chick fibroblast c-erbA-alpha and the human placental c-erbA-beta modulate cis-acting regulatory sequences of two thyroid hormone responsive genes; rat GH and PRL. From these results we conclude: 1) in a receptor deficient cell line (235-1) both c-erbA subtypes act as hormone-dependent modulators of PRL gene expression and hence function as thyroid hormone receptors, 2) in two different receptor containing cell lines (GH4C1 and GH1), both c-erbA proteins act in a hormone-independent fashion to regulate PRL and GH expression. This suggests that events other than ligand binding can result in formation of a c-erbA protein that modulates transcription of thyroid hormone responsive genes, 3) no qualitative functional differences were detected between alpha- and beta-c-erbA subtypes, and 4) depending on the cell-type, L-T3 acts through its endogenous receptor to stimulate (GH4C1) or suppress (GH1) expression of a chimeric PRL construct. In these cells, c-erbA expression results in the same positive or negative response as the endogenous receptor except that the response occurs in the absence of hormone. These results suggest that the endogenous receptor and the c-erbAs act by augmenting the effect of transcription factors which can positively or negatively control gene expression.

Affinity Labels↗
PubMed1988

Application of biotin-avidin system, determination of circulating immune complexes, and evaluation of antibody response in different hydatidosis patients.

The avidin-biotin-peroxidase complex enzyme-linked immunosorbent assay (ABC-ELISA) and standard ELISA were used for the detection of Echinococcus granulosus antibody in sera of 101 patients operated on for hydatid disease, 40 patients with miscellaneous nonhydatid diseases, and 61 normal subjects. Sensitivity and specificity of the two procedures were comparable and the geometric mean antibody titer detected with ABC-ELISA was higher than with standard ELISA. The ABC-ELISA is a sensitive, specific, simple, and convenient method for diagnosing hydatidosis.

Animals↗
PubMed1987

Effects of intermittent diethylstilbestrol diphosphate administration on the R3327 rat prostatic carcinoma.

Clinical trials have utilized intermittent diethylstilbestrol diphosphate (DES) therapy in advanced symptomatic prostatic carcinoma to diminish the morbidity of standard endocrine therapy. To determine the effect of intermittent DES administration on the Dunning R3327 rat prostatic adenocarcinoma 60 days following tumor implant, 6 groups were randomly assigned: control (N = 8), castrate (N = 10), high dose DES (N = 8, 1.6 micrograms/ml DES continuously in drinking water), low dose DES (N = 10, 0.4 microgram/ml continuously in drinking water), intermittent high dose DES (N = 10, 1.6 micrograms/ml DES in drinking water for 1 week, then off for 3 weeks), and intermittent low dose DES (N = 10, 0.4 microgram/ml DES for 1 week, then off for 3 weeks). Results indicate that low or high dose DES, and intermittent low or intermittent high dose DES during the week of administration were able to reduce serum testosterone to castrate levels (0.1 ng/ml). After withdrawal of intermittent DES, serum testosterone returned toward control levels (1.0 ng/ml). Initial mean tumor burden between control and treatment groups was not significantly different. All DES exposed rats had a tumor volume at death (range, 15.6-18.3 cm3) smaller than control (mean, 25.4 cm3) or castrate (mean, 40.8 cm3) rats. Despite this significant survival advantage from the time of randomization was achieved only in castrate (median survival, 331 days) or high dose DES (median survival, 359 days) groups compared to control (median survival, 225 days). Similarly, significant prolongation in tumor doubling time was achieved only by rats receiving castration or high dose DES. Intermittent DES administration controls tumor volume but does not provide a survival advantage. In this respect, intermittent DES is inferior to castration.

Animals↗
PubMed1987

Cytotoxic activity of a polyamine analogue, monoaziridinylputrescine, against the PC-3 human prostatic carcinoma cell line.

We have previously demonstrated that prostate and prostate-derived rodent tumors can be manipulated into increasing their accumulation of radiolabeled putrescine by alpha-difluoromethylornithine (DFMO)-induced depletion of intracellular putrescine and spermidine. As methods which increase intracellular accumulation of cytotoxic agents often increase the chemotherapeutic effectiveness of the agent, we examined whether an alkylating derivative of putrescine would be cytotoxic to tumor cells. We present here our findings on the cytotoxicity of the aziridinyl derivative of putrescine (AZP) against prostatic cancer cells. The apparent Km for putrescine was 2.5 microM with or without DFMO pretreatment and the apparent Ki for AZP was 1 microM with or without DFMO pretreatment. Intracellular polyamine depletion by DFMO pretreatment resulted in a 3.7-fold greater accumulation of AZP compared to non-DFMO-treated cells. The growth inhibitory activity of AZP was increased with prior polyamine depletion by DFMO with the 50% effective dose decreasing from 18 microM to 2.1 microM. Putrescine was able to block the cytotoxic effect of AZP. Putrescine was also able to rescue the AZP-treated PC-3 cells for up to 6 h following a 1-h exposure to AZP. It appears that aziridinylputrescine behaves like putrescine in that it competes with putrescine for uptake into the cell and, like putrescine, has its uptake into the cell increased by prior polyamine depletion. It differs from putrescine in that it expresses cytotoxic activity and inhibits the growth of the human prostate-derived PC-3 cell line. This cytotoxic activity is also increased by prior polyamine depletion. The cytotoxic behavior of AZP is dependent both on the concentration and duration of exposure. Putrescine can rescue the cells from the effect of AZP. AZP is a potentially useful cytotoxic analogue that utilizes the polyamine transport system for its uptake into the cell.

Cell Line↗
PubMed1987

Hippocampal signal transmission to the pedunculopontine nucleus and its regulation by dopamine D2 receptors in the nucleus accumbens: an electrophysiological and behavioural study.

The integrative role of the nucleus accumbens and subpallidal area in relaying hippocampal signals to the mesencephalic locomotor region in the brainstem was investigated electrophysiologically in urethan-anaesthetized rats. A behavioural study of the functional connections was also performed in freely moving rats. In the electrophysiological experiments, subpallidal output neurons to the pedunculopontine nucleus and the adjacent ventral gray were first identified by their antidromic responses to electrical stimulation of the pedunculopontine nucleus. Hippocampal stimulation was then shown to inhibit orthodromically some of these subpallidal neurons. The inhibitory response was attenuated following microinjection of a dopamine D2 agonist (LY 171555), but not a D1 agonist (SKF 38393), into the accumbens. This suggests that signal transmission from the hippocampus to the subpallidal output neurons to the pedunculopontine nucleus is modulated by a D2 receptor-mediated mechanism in the nucleus accumbens. Injections of N-methyl-D-aspartate into the ventral subiculum of the hippocampus resulted in a threefold increase in locomotor responses. Injection of a D2 agonist into the accumbens reduced the hyperkinetic response dose-dependently and suggests that D2 receptors regulate locomotor responses initiated by the hippocampal-accumbens pathway. Injection of nipecotic acid, a GABA uptake inhibitor, into the subpallidal area or of procaine, a neural transmission blocker, into the region of the pedunculopontine nucleus, also reduced significantly the hippocampal-induced hyperkinetic response. These results provide evidence of limbic (e.g. hippocampus) influences on locomotor activity by way of nucleus accumbens-subpallidal-pedunculopontine nucleus connections which may contribute to adaptive behaviour. Signal transmission from the hippocampus may be regulated by a dopamine D2 receptor mechanism in the accumbens, presumably mediated by the converging mesolimbic dopaminergic input from the ventral tegmental area.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1986

Transformation of the chick oviduct progesterone receptor in the absence of hormone.

Chicken oviduct progesterone receptor in cytosol was found to be transformed from the 8S to 4S form by incubation at 25 degrees C as well as by 0.3 M KCl in the absence of hormone. Heat transformation of ligand-free receptor took place at a much slower rate than that of ligand-bound receptor. The eventual percentage of transformation, however, was almost the same. The 4S form of the receptor transformed by KCl in the absence of hormone could bind to DNA-cellulose, but not to nuclei. However, upon exposure it acquired the ability to bind to nuclei. It was shown that the transformed ligand-free receptor could bind to progesterone to form the normal activated steroid-receptor complex. Conversely, when activated 4S progesterone-receptor complex was treated with DCC to peel off the hormone, a resulting ligand-free receptor was formed which behaved just like the KCl-transformed receptor in the absence of hormone.

Animals↗
PubMed1986

Dopamine enhances terminal excitability of hippocampal-accumbens neurons via D2 receptor: role of dopamine in presynaptic inhibition.

The effects of dopamine on the axonal terminals of hippocampal-nucleus accumbens (HIPP-ACC) neurons were investigated in urethane-anesthetized rats using extracellular single-unit recording techniques. Antidromic responses recorded in the ventral subiculum of the hippocampus were evoked by stimulation of the medial accumbens. Baseline terminal excitability of these neurons, established by threshold stimulation of the accumbens, was markedly enhanced by conditioning stimulation (10 Hz) of the ventral tegmental area (VTA), the origin of the mesolimbic dopaminergic neurons. Iontophoretic application of sulpiride, a selective D2 antagonist, onto the HIPP-ACC terminals attenuated the increased terminal excitability of these neurons produced by conditioning VTA stimulation, while intraperitoneal injection of SCH23390, a selective D1 antagonist, failed to attenuate this effect. Iontophoretic application of dopamine or its selective D2 agonist, LY171555, onto the terminals of the HIPP-ACC neurons mimicked the prolonged enhancement of the terminal excitability produced by VTA stimulation, whereas SKF38393, a D1 agonist, had no effect. The effects of VTA stimulation, dopamine and LY171555 application were similar after the accumbens had been pretreated with ibotenic acid, suggesting a direct action of dopamine on the axonal terminals of HIPP-ACC neurons, and that changes in terminal excitability were not mediated via interneurons or feedback pathways from the accumbens to the hippocampus. Since iontophoretic application of potassium, a depolarizing agent, also enhanced the terminal excitability of the HIPP-ACC neurons, it appears that dopamine depolarized, via D2 receptors, the axonal terminals of HIPP-ACC neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

An electrophysiological study of the neural projections from the hippocampus to the ventral pallidum and the subpallidal areas by way of the nucleus accumbens.

The integrative role of the ventral striatum in transmitting signals from the hippocampus to the ventral pallidal and subpallidal areas was investigated in urethane-anaesthetized rats using an extracellular single-unit recording technique. Neurones of the nucleus accumbens were first activated by single-pulse stimulation of the ventral subiculum of the hippocampus. Further tests were made to investigate whether these accumbens neurones could be activated antidromically by stimulation of either the ventral pallidal or subpallidal areas. More than 4 times as many accumbens neurones, activated by hippocampal stimulation, responded antidromically to stimulation of subcommissural ventral pallidum than to stimulation of the sublenticular subpallidal area. This observation suggests that the hippocampus has preferential inputs to accumbens efferent neurones which project monosynaptically to the ventral pallidum. Spontaneously active neurones in the ventral pallidum and subpallidal area were inhibited by stimulation of the ventral subiculum of the hippocampus. These inhibitory responses were reduced when glutamic acid diethyl ester, a glutamate antagonist, was microinjected into the medial accumbens, apparently blocking the hippocampal-accumbens glutamatergic synapses to both the ventral pallidal-directed and the subpallidal-directed accumbens efferents. This evidence suggests that signals from the hippocampus reach ventral pallidal and subpallidal regions by way of the nucleus accumbens. The presence of a projection from ventral pallidal and subpallidal regions to the brainstem mesencephalic locomotor region further supports the hypothesis that limbic (e.g. hippocampus) can influence somatomotor activities by way of the nucleus accumbens and its efferent projection to ventral pallidal and subpallidal regions.

Animals↗
PubMed1984

Electrophysiological responses of neurones in the nucleus accumbens to hippocampal stimulation and the attenuation of the excitatory responses by the mesolimbic dopaminergic system.

Extracellular single unit recordings were obtained from neurones in the nucleus accumbens of urethane anaesthetized rats. Single pulse stimulation (300-800 microA, 0.15 ms, 0.5-1.5 Hz) of the ventral subiculum of the hippocampus strongly excited silent and spontaneously active (3-6 spikes/s) medial accumbens neurones. The majority of neurones excited by hippocampal stimulation were quiescent and identified only by the elicited action potentials. Neurones on the dorso-medial border of the nucleus accumbens and adjacent lateral septum, with a faster spontaneous discharge rate (8-12 spikes/s), were inhibited by hippocampal stimulation. In the ventral border of the accumbens and the olfactory tubercle, hippocampal stimulation also inhibited the fast-firing (greater than 20 spikes/s) neurones. When trains of 10 conditioning pulses (300-800 microA, 0.15 ms, 10 Hz) were delivered to the ventral tegmental area (VTA) 100 ms before each single-pulse stimulation of the hippocampus, the excitatory responses of the silent and spontaneously active accumbens neurones were attenuated. The possibility of this relatively prolonged attenuation effect being dopamine-mediated was supported by several lines of evidence. Dopamine, applied iontophoretically, reduced markedly the excitatory response of accumbens neurones to hippocampal stimulation. Iontophoretically applied dopamine mimicked the attenuating effect produced by VTA conditioning stimulation in the same neurone. The attenuating effects of VTA conditioning stimulation on the activation of accumbens neurones by hippocampal stimulation was reduced by: (1) administration of 6-hydroxydopamine to the VTA 2 days and 7-9 days prior to the recording session, (2) the intraperitoneal injection of haloperidol 1 h before the recording session, and (3) the iontophoretic application of trifluoperazine to accumbens neurones. These observations support the hypothesis that the attenuating effects of the mesolimbic dopamine system on limbic inputs to the nucleus accumbens may have a role in limbic-motor integration.

Animals↗