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H H Yin

Publications and source records attributed to H H Yin.

9 recordsLinked to original sources
PubMed2002

Reinforcer devaluation abolishes conditioned cue preference: evidence for stimulus-stimulus associations.

In the conditioned cue preference (CCP) task, the subject is presented with a cue paired with food reward, resulting in a preference for the paired cue when allowed to choose later. To clarify the learning involved, the authors devalued the reinforcer after training by inducing a taste aversion to the food. In five 30-min sessions, rats were confined in 1 arm of a radial arm maze and presented with food. These reinforced sessions alternated with 5 unreinforced sessions in a nonadjacent arm. Devaluation was then accomplished in 1 group by inducing taste aversion; controls received either saline or unpaired lithium chloride treatment. When tested later, both the saline group and the unpaired group preferred the previously reinforced arm, but the devalued group showed aversion to it. Thus, CCP is mediated by the stimulus-reinforcer association; when the reinforcer is devalued, the preference is also abolished.

Animals↗
PubMed2000

Effect of total flavonoids of hippophae rhamnoides on contractile mechanics and calcium transfer in stretched myocyte.

OBJECTIVE: To study the role of total flavonoids of hippophae rhamnoides in improving contractile [correction of contactile] function of stretched cardiac myocyte. METHOD: Flavonoids were given to stretched myocytes which were proved their contractile function decline and then myocyte contractile mechanics characteristics and calcium transfer were measured. RESULT: Flavonoids increased myocyte contractility, as indicated by myocyte shortening, velocity of shortening, peak +dL/dt and peak -dL/dt during shortening, in a concentration-dependent manner (r>0.9, P<0.001), and with no relation to the intracellular calcium transfer in the myocytes. CONCLUSION: Flavonoids of the traditional Chinese drug hippophae rhamnoides is effective in improving the contractile function of stretched cardiac myocyte in low dosage.

Animals↗
PubMed1998

Transcranial Doppler assessment of brain death in children.

AIM: To estimate the values of transcranial doppler (TCD) in the determination of brain death in children. METHOD: Fifty-eight comatose children (from 2 days to 13 years, median 28 months) with Glasgow Coma Sores of < or = 7 had TCD examinations. The waveforms and the cerebral blood flow velocities of the middle cerebral arteries (MCAs) were monitored at intervals. Electroencephalogram (EEG) was recorded continuously in 34 patients. Twenty children survived, 38 died, 17 patients met the criteria for determination of brain death by clinical and EEG criteria or by clinical criteria alone. The prevalence of retrograde diastolic flow (RDF) was analysed by using chi-square test. RESULTS: All the brain death patients displayed "special" TCD waveforms including RDF or small systolic forward flow (SFF). RDF appeared in 14, 2 and 3 patients in the brain death, non-brain death and survival group respectively. The occurrence of RDF in the brain death group was significantly higher than in the other two groups (p < 0.01). Persistence of RDF or SSF and direction of flow index < 0.8 in the MCAs for more than 2 hours in serious comatose children, was a reliable indicator to predict or confirm brain death. Using this criteria, no false negative or false positive results were found in this group of patients. CONCLUSION: TCD has a high sensitivity and specificity in the determination of brain death in children.

Adolescent↗
PubMed1975

The cell surface.

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Agglutination↗
PubMed1975

The relation of endogenous adenosine cyclic 3':5'-monophosphate to the antagonistic effects of adenosine and colchicine on cell shape.

Adenosine and colchicine have antagonistic effects on cell shape. When Chinese Hamster lung fibroblasts (CHE36-6) or SV40 transformed 3T3 (SV3T3) cells are incubated with colchicine (1 muM) for one hour at 37 degrees C, they round up into spheres with short spikes. Cells treated with adenosine (1 muM-minus 4 mM) for one hour become refractile and develop spindly processes. However, when the two compounds are added simultaneously, the characteristic responses to either drug are abolished and the cells appear normal. The counteraction is specific for adenine and its derivatives, adenosine being the most effective of the compounds we tested. Accumulation of colchicine or adenosine is not altered significantly by the presence of the other drug, ruling out decreases in uptake as the basis of the mutual antagonism. The morphological changes can be observed under conditions where there are no changes in intracellular cAMP levels (such as incubation with low concentrations of adenosine or cordycepin, an adenosine analog that cannot be directly converted to cAMP). Colchicine does not alter cAMP content of control or adenosine-treated cells. These data show that adenine compounds have potent effects on cell shape, and the antagonistic effects of adenosine and colchicine on cell shape are not mediated through changes in intracellular cAMP levels.

Adenine↗
PubMed1973

A comparative evaluation of the distribution of concanavalin A-binding sites on the surfaces of normal, virally-transformed, and protease-treated fibroblasts.

The topographical distributions of concanavalin A-binding sites on the surfaces of 3T3, proteasetreated 3T3, and simian virus 40-transformed 3T3 cultured mouse fibroblasts appear to be different, as shown by a shadow-cast replica technique using concanavalin A and a hemocyanin marker, or as shown previously on isolated membranes with concanavalin A coupled to ferritin. However, chemical fixation of cells before labeling with concanavalin A and hemocyanin, or labeling exclusively at 4 degrees , allows one to distinguish between inherent concanavalin A-binding-site topography and potential rearrangement of sites induced by the action of the multivalent concanavalin A molecule itself. The inherent distribution of binding sites on 3T3, protease-treated 3T3, and transformed cells is actually the same on all cells, i.e., dispersed and random. Treatment of unfixed transformed or protease-treated 3T3 cells, but not normal 3T3 cells, with concanavalin A and hemocyanin at 37 degrees (or at 4 degrees with subsequent warming to 37 degrees ), however, results in clustering of binding sites, presumably due to crosslinking of neighboring lectin-binding sites by the quadrivalent concanavalin A. Thus, the underlying difference between concanavalin A-binding sites on normal as compared with transformed or protease-treated normal cells lies not in the inherent topography of binding sites, but rather in the susceptibility of the sites to aggregation by concanavalin A. The latter may reflect an increased mobility of lectin-binding sites on transformed or protease-treated cells.

Animals↗