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Biomedical subjects

Y C Sun

Publications and source records attributed to Y C Sun.

32 records · Page 2Linked to original sources
PubMed1993

Multiresolution wavelet analysis of evoked potentials.

Neurological injury, such as from cerebral hypoxia, appears to cause complex changes in the shape of evoked potential (EP) signals. To characterize such changes we analyze EP signals with the aid of scaling functions called wavelets. In particular, we consider multiresolution wavelets that are a family of orthonormal functions. In the time domain, the multiresolution wavelets analyze EP signals at coarse or successively greater levels of temporal detail. In the frequency domain, the multiresolution wavelets resolve the EP signal into independent spectral bands. In an experimental demonstration of the method, somatosensory EP signals recorded during cerebral hypoxia in anesthetized cats are analyzed. Results obtained by multiresolution wavelet analysis are compared with conventional time-domain analysis and Fourier series expansions of the same signals. Multiresolution wavelet analysis appears to be a different, sensitive way to analyze EP signal features and to follow the EP signal trends in neurologic injury. Two characteristics appear to be of diagnostic value: the detail component of the MRW displays an early and a more rapid decline in response to hypoxic injury while the coarse component displays an earlier recovery upon reoxygenation.

Algorithms↗
PubMed1993

[Studies on pharmacologic disposition of adriamycin in dog after hepatic arterial embolization with adriamycin carboxymethyl-dextran-microspheres].

The ion exchange adriamycin carboxymethyl-dextran-microspheres (AD-CM-DMS) was chosen as a model preparation. Pharmacokinetics, targeting and embolization effects of the microspheres were studies after hepatic arterial embolization in vivo in dogs. After hepatic arterial infusion, the concentrations of ADM in peripheral vein blood and hepatic tissue were determined by HPLC. The peak concentrations were (0.558 micrograms/ml for AD-CM-DMS and 1.013 micrograms/ml for ADM solution. T1/2 (alpha), T1/2 (beta) and MRT of AD-CM-DMS were respectively 2.82, 3.19 and 1.28 times as much as those of ADM solution. At the target site, the tissue concentrations of AD-CM-DMS were respectively 8.0 and 9.1 times those of ADM solution. The dynamic vessel angiography revealed no external and internal collaterals and no complete degradation of AD-CM-DMS after sixteen weeks was observed. These results suggest that AD-CM-DMS are useful as embolic agent for the treatment of hepatic cancer. It could facilitate intensive chemotherapy with minimum systematic side effect.

Animals↗
PubMed1993

Comparison of preoperative and postoperative iliohypogastric ilioinguinal nerve block for pediatric herniorrhaphy patients.

The purpose of this study was to compare the effects of preoperative and postoperative iliohypogastric ilioinguinal nerve block (IINB) performed on 30 pediatric patients having elective unilateral herniorrhaphy for postoperative pain control and to discuss the theory of post-injury hypersensitivity of the nerves system. The patients were assigned into two groups (A = 15, B = 15) randomly. Both groups were given GA during the surgical procedure except that group A received IINB 15 minutes prior to skin incision and group B immediately after skin closure. The local anesthetic used was 0.25% bupivacaine and the dosage was 1 mg/Kg. The heart rate, BP, and anesthetic concentration (halothane) were recorded during the procedure and postoperative pain was assessed by using the modification of the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) behavior pain score which were taken at 1 hr, 3 hr (POR), 6 hr, and 24 hr (ward) postoperatively. Group A had less pain at 1 hr and 3 hr than group B postoperatively and is statistically significant. There was no statistically significant in pain score at 6 hr and 24 hr between the two groups.

Adolescent↗
PubMed1992

Progression delay of prostate tumor skeletal metastasis effects by bisphosphonates.

Prostate tumor cell metastasis to the axial skeleton was induced in male Copenhagen rats using the intravenous injection of syngeneic metastatic R3327-MATLyLu tumor cells and concomitant caval vein clamping. The proliferation of tumor cells in the lumbar region was monitored by the progression, within 19 days post tumor cell injection, of hindleg paralysis which appeared in these animals. Histology confirmed the presence of tumor cells within the lumbar spine in 100% of cases displaying hindleg paralysis. Treatment with either of the bisphosphonate drugs, Cl2MDP or APD, suppressed and delayed the development of hind leg paralysis. Bisphosphonate treatment may be expected to delay the onset of axial skeletal metastasis effects in prostate cancer patients.

Animals↗
PubMed1989

[A paracentric inversion in the salivary gland chromosome 3R of Anopheles sinensis].

An inversion heterozygote has been found in the fourth stage larvae of the laboratory line of Shanghai Anopheles sinensis in our laboratory, the frequency of occurrence of the heterozygote being 2 to 5%. The characteristic inversion loop formed in the midst of chromosome 3R together with the break points arises from 26C to 30A segment of the chromosomes. This inversion paracentric is the first record in the literature available and may be of significance as a genetic marker in studying the inter-specific variation of Anopheles sinensis.

Animals↗
PubMedDate not supplied

Neural changes in acute arthritis in monkeys. II. Increased glutamate immunoreactivity in the medial articular nerve.

Glutamate and other excitatory amino acids have been shown to play a key role in nociception and the hyperalgesia associated with the acute inflammatory response. In an effort to understand more fully the role of Glu in this process, we determined that there is Glu in a percentage of axons in the medial articular nerve (MAN) of monkeys, a source of preterminal afferent fibers innervating the knee joint. After induction of the experimental knee joint inflammation with a kaolin/carrageenan mixture, comparison was made of the percentage of Glu positive axons in the MAN on the side of the inflammation versus the contralateral MAN using post-embedding immunogold electron microscopic methods. A doubling in the percentage of Glu-containing axons was observed on the side of the experimental arthritis as compared to the MAN of the other side or of uninjected controls. Glu positive axons were unmyelinated or were included in the small, thinly myelinated group in control nerves. Following induction of the inflammation, axonal diameter measurements revealed an increase in Glu content primarily in the small, thinly myelinated axons, which correspond to the group III afferent fibers. These increases were observed in the anesthetized preparation only when injection of kaolin/carrageenan was combined with joint flexion and mechanical stimulation. The dramatic increase in percentages of fibers stainable for Glu in the MAN following the induction of inflammation suggests that Glu content is greatly increased in the afferent fibers and may be a major contributor to the enhanced responses of sensory neurons in inflammatory states such as arthritis.

Acute Disease↗
PubMedDate not supplied

Dietary intake and residues of organochlorine pesticides in foods from Hsinchu, Taiwan.

The levels of contamination with various organochlorine pesticides (such as total HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endosulfan, and total DDT) of different foods from 3 traditional markets were determined to estimate Taiwanese daily intake of organochlorine pesticides. Of the 18 organochlorine pesticides investigated, alpha-HCH, beta-HCH, lindane, delta-HCH, heptachlor, heptachlor epoxide, dieldrin, endrin, alpha-endosulfan, p,p'-DDE, and p,p'-DDT were detected at concentrations ranging from 0.26 to 10.2 ng/g wet weight. Contamination with organochlorine pesticides followed the order heptachlor > dieldrin > alpha-endosulfan > HCH isomers > heptachlor epoxide > DDT. Frequencies of detection of organochlorine pesticide residues ranged from 2.0 to 52.3%. alpha-Endosulfan was the most frequently detected organochlorine pesticide in the foods analyzed, followed by heptachlor epoxide (47.6%) and alpha-HCH (38.9%). Estimated daily intakes (EDIs) of organochlorine pesticides from foods were 1.137 micrograms for total HCH, 2.147 micrograms for heptachlor, 0.702 microgram for heptachlor epoxide, 0.624 microgram for endosulfan, 0.098 microgram for cyclodiene, and 0.541 microgram for total DDT. These EDIs were only 0.075% of the acceptable daily intake (ADI) for lindane, 47.5% of ADI for heptachlor and heptachlor epoxide, 0.045% of ADI for total DDT, and 1.01% of ADI for aldrin and dieldrin. Therefore, consumption of the foods analyzed does not pose a risk to consumer health.

Chromatography, Gas↗