Biomedical subjects

D C Chen

Publications and source records attributed to D C Chen.

76 records · Page 5Linked to original sources

PubMedDate not supplied

Effect of subtype-selective opioid receptor blockers on nitrous oxide antinociception in rats.

Nitrous oxide antinociception in rats was evaluated by the warm water tail withdrawal test following central pretreatment with blockers of various opioid receptor subtypes. The analgesic dose, 50% (AD50) value for nitrous oxide antinociception was significantly elevated by MR-2266 (which is relatively selective for kappa-opioid receptors) and increased to a lesser degree by ICI-174,864 (which is selective for delta-opioid receptors). However, pretreatment with beta-funaltrexamine (which is selective for mu-opioid receptors), even at extremely high doses, was ineffective in altering the AD50 for nitrous oxide antinociception. According to these findings, nitrous oxide antinociception, as evaluated in this paradigm, appears to be mediated by kappa- and possibly delta- but not mu-opioid receptors.

Animals↗

PubMedDate not supplied

A new look at radionuclides therapy in metastatic disease of bone (review and prospects).

Bone-seeking radionuclides have been used to treat bone pain due to metastatic bone disease for over 40 years. More than 10 clinical studies using radiostrontium (Sr-89) have shown benefit in about 70-80% of patients having refractory bone pain from prostate, breast and other metastatic bone cancers, with minimal hematological toxicity. Other radionuclides, such as, radiophosphate (P-32), Yttrium-90, lodine-131, Rhenium-186, have also been used. Tumor necrosis has been found within the range of beta irradiation from the surrounding shell of bone incorporating the radionuclide. New strategies using radionuclides may be able to provide more effective methods of treatment, perhaps, beyond palliation. For example, the effect of low dose continuous radiation can be potentiated by hypoxic cell sensitizers. In addition, the kinetics of radionuclide uptake and retention can be modulated to increase the dose of radiation delivered to osteoblastic metastatic lesions, such as osteosarcoma.

Bone Neoplasms↗

PubMedDate not supplied

B-cell immunoblastic sarcoma as a cause of a photopenic lesion on bone scintigraphy: an initial description.

Photopenic metastatic lesions on bone scintigraphy have been previously reported. However, this finding is not emphasized for B-cell immunoblastic sarcoma. We report a case of B-cell immunoblastic sarcoma, which presented as an aggressive pancoast tumor with extensive rib destruction. Bone scintigraphy findings demonstrated a photopenic lesion with high gallium avidity. Correlative chest radiograph and CT scan are described.

Bone Neoplasms↗

PubMedDate not supplied

The electrophysiological effects of alcoholized rhubarb solution in feline heart in vivo.

The effects of Chinese medicine, alcoholized rhubarb, on cardiac electrophysiology and contractile force were studied by using monophasic action potential (MAP) techniques with an improved pressure-electrical transducer epicardial electrode and/or an endocardial pressure-contact electrode catheter in 27 feline hearts in vivo. The results of the experiments were as follows: 1) Alcoholized rhubarb solution (1.5 g/kg) caused a greater increase in the MAP amplitude (from 18.8 +/- 0.62 mV to 26.7 +/- 3.87 mV, p < 0.01), in the MAP maximum rate of rise of phase 0 (from 1.7 +/- 0.13 V/sec to 2.6 +/- 0.43, p < 0.01), and in the MAP duration at 50% and 90% repolarization (from 194.3 +/- 14.00 msec to 216.3 +/- 6.30 msec and from 238.8 +/- 21.41 msec to 280.5 +/- 14.68 msec, respectively, p < 0.01), and a decrease in the heart rate (from 130.8 +/- 12.10 bpm to 110.8 +/- 10.35 bpm, p < 0.01) in the epicardial monophasic action potentials after rhubarb solution administration for 1 min. 2) The ventricular contractile force of the feline heart in vivo was also significantly increased (11.1 +/- 0.52 g to 14.0 +/- 1.41 g, p < 0.01) by rhubarb solution. 3) A dose-dependent relation of alcoholized rhubarb solution was found and indicated that lower doses (1.0-1.5 g/kg) had an excitatory effect, while a higher dose (2.0 g/kg) had inhibitory or toxic effects on the intact feline heart. The present study provides evidence that Chinese rhubarb solution has electrophysiological effects on the feline heart in vivo.

Action Potentials↗