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Biomedical subjects

J Chu

Publications and source records attributed to J Chu.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Augmented effect of Composite Radix Salviae Miltiorrhizae Injection on radiosensitivity of leukemia cells].

OBJECTIVE: To explore the effect of Composite Radix Salviae Miltiorrhizae Injection (CSMI) on radiosensitivity of leukemia cells. METHODS: Semisolid agar culture and flow cytometry assay were performed for studying the change in radiosensitivity of HL60 cell line and fresh human leukemia cells after exposing to CSMI. RESULTS: The D0(the inverse of the slope of the survival curve) and SF2(survival fraction at 2 Gy) of HL60 cell line were decreased from 1.53, 0.34 to 0.93, 0.12, respectively and apoptosis rates after radiation were raised significantly by CSMI. Furthermore, the concentration of CSMI and the time of mixed culture with CSMI before irradiation had positive relation to the effects mentioned above. Compared with control group, CSMI could increase the radiation-induced apoptosis of fresh leukemia cells (5.89 +/- 2.91% vs 12.05 +/- 3.06%). CONCLUSION: CSMI could obviously enhance the radiosensitivity of leukemia cells.

Drugs, Chinese Herbal↗
PubMed1998

[Effect of water extract of Poria on cytosolic free calcium concentration in brain nerve cells of neonatal rats].

OBJECTIVE: To investigate the effect of Poria cocos, a Chinese medicinal herb, on cytosolic free calcium concentration ([Ca2+]i) in brain nerve cells of neonatal rats. METHODS: Double-wave-length fluorospectrophotometer and laser confocal scanning microscope were used to measure the [Ca2+]i in neurons. RESULTS: The water extract of poria (31-250 mg/L) induced a dose-dependent increase in [Ca2+]i, but poria at the range of 500 mg/L did not cause [Ca2+]i to increase. It was also shown that the water extract of poria significantly inhibited the increment of [Ca2+]i induced by 500 mumol/L glutamate. The similar results were observed from the experiments in primarily cultured hippcampal neurons of neonatial rats by using laser confocal scanning microscope. CONCLUSIONS: The water extract of Poria cocos has the effect of bidirectional regulation on cytosolic free calcium in brain nerve cells.

Animals↗
PubMed1997

Viral encephalitis masquerading as a fulminant anticholinergic toxidrome.

CASE REPORT: Emergency physicians are well versed in the recognition and management of certain poisonings which present with characteristic toxidromes. We present a case of a young pharmacy student who presented with altered mental status, tachycardia, facial flushing, dilated pupils, and dry skin and mucous membranes presumably due to anticholinergic poisoning. She improved with a combination of benzodiazepines and the acetylcholinesterase inhibitor physostigmine. However, following resolution of her initial symptoms, she became ill again and the subsequent neurologic evaluation revealed a diencephalic lesion consistent with a viral encephalitis. The acute anticholinergic signs and symptoms resulted from this lesion in an area of large cholinergic outflow. Although recognition and management of her acute anticholinergic findings were appropriate, they were not the manifestations of an acute anticholinergic ingestion.

Adult↗
PubMed1997

Does EMG (dry needling) reduce myofascial pain symptoms due to cervical nerve root irritation?

OBJECTIVE: EMG examination at tender points affects myofascial pain symptoms related to cervical nerve root irritation. METHODS: Consecutive patients with neck and arm pain had physical examinations immediately before and after having EMGs of bilateral C3-C8 myotomes. Patients were randomly chosen for EMG either at the most tender point along the palpated myofascial band or at a nonselected site. The myotomal presence of > or = 30% incidence of normal duration and amplitude, and polyphasic motor unit potentials confirm the diagnosis of cervical nerve root irritation. RESULTS: 52% returned patient questionnaires 2 weeks post EMG examination. Group I (82/122 patients [67.2%]), averaged pain relief of 51.8 +/- 21.9%, a mean of 10.2 +/- 8 days; 14% had > or = 75% relief. The number of days of pain relief correlated positively with the percentage of pain relief (p < 0.005), but negatively with the number of nerve roots involved on EMG (p < 0.05). Group 2 (23/42 patients [54.8%]), averaged relief of 39.0 +/- 18.7%, lasting 8.8 +/- 11.2 days. None had > or = 75% pain relief. Both groups' duration of pain symptoms affected onset of relief. Evidence of bilateral multiple-level cervical nerve root irritation, especially noted at bilateral C6 and C7 levels. CONCLUSION: EMG at tender points on myofascial bands tends to improve symptoms. Needling these points elicits motor endplate activity and twitches, and induces more relief than when needling random points.

Adult↗
PubMed1996

Characterization of seed oil bodies and their surface oleosin isoforms from rice embryos.

Plant seeds store triacylglycerols in discrete organelles called oil bodies. An oil body stores a matrix of triacylglycerols surrounded by phospholipids and alkaline proteins termed oleosins. Oil bodies in rice seeds are present in embryos and aleurone layers. They do not coalesce in crowded environments, as observed on electron microscopy. The detected isoelectric point of purified rice oil bodies is pH 6.2. This implies that rice oil bodies possess a negatively charged surface at neutral pH. The suspension of rice oil bodies in pH 6.5 buffer induces aggregation. Presumably, the negatively charged surface causes electrostatic repulsion that maintains rice oil bodies as discrete organelles. Rice oil bodies lose their integrity on trypsin treatment. Undoubtedly, oleosins play an important role in the stability of oil bodies. There are two oleosin isoforms in rice oil bodies. Antibodies raised against these two homologous isoforms do not cross-recognize each other. Both isoforms are restricted to oil bodies, as detected on immuno-assaying. Partial amino acid sequences of these two isoforms were obtained, and compared with the deduced sequences of two maize and two rice oleosin genes. The comparison confirmed that the two major proteins in rice oil bodies are the two oleosin isoforms.

Amino Acid Sequence↗
PubMed1996

Sidestream smoke inhalation decreases respiratory clearance of 99mTc-DTPA acutely.

BACKGROUND: The permeability of the alveolar-capillary barrier to an inhaled aerosol of technetium 99m labelled diethylenetriamine penta-acetate (99mTc-DTPA) is used as an index of alveolar epithelial injury. Permeability is greatly increased in active smokers. AIMS: To determine the effect of sidestream smoke inhalation on permeability as this has not been described previously. METHODS: We measured lung clearance of inhaled 99mTc-DTPA aerosol in 20 normal non-smoking subjects before and after exposure to one hour's sidestream smoke inhalation. RESULTS: Measured carbon monoxide (CO) levels rose to maximum of 23.5 +/- 6.2 ppm (mean +/- SD) from baseline values of 0.6 +/- 1.3 (p < 0.001) and plasma cotinine levels to a maximum of 9.5 +/- 4.5 nmol/L (mean +/- SD). The half time (T1/2 in minutes) for 99mTc-DTPA clearance rose from baseline 69.1 +/- 15.6 (mean +/- SD) to 77.4 +/- 17.8 (p < 0.05) after smoke exposure. No effect of 99mTc-DTPA scanning or of sidestream smoke was demonstrated on lung function. CONCLUSIONS: We conclude that low level sidestream smoke inhalation decreases 99mTc-DTPA clearance acutely in humans. The mechanism of this unexpected result is not established but may include differences in constituents between sidestream and mainstream smoke, alterations in pulmonary microvascular blood flow, or changes in surfactant due to an acute phase irritant response.

Adult↗
PubMed1996

Alignment of multi-segmented anatomical features from radiation therapy images by using least square fitting.

A least square fitting algorithm for alignment of multi-open-curved segments and point pairs of anatomical features obtained from both portal images and simulation radiographs has been developed for patient position verification in radiation therapy. A coordinate system associated with each curved segment pair is constructed so that the discrepancies of each segment pair can be obtained easily. The algorithm allows users to select not only multiple curve pairs but also individual point pairs on the important anatomic landmarks. The misregistration is measured by the sum of the position deviation of individual point pairs and ordinate discrepancies of all segment pairs from their corresponding coordinate systems. A mathematical minimization method is applied to seek an optimal transformation for matching of all segment and/or point pairs involved. The reliability of the algorithm has been tested with both phantom and clinical images. The test results indicate that the typical errors are less than 1 mm and 1 degrees in translation and rotation, respectively.

Algorithms↗
PubMed1996

[Effects of ding zhi pills on the scopolamine-induced impairment of passive avoidance in rats].

The Ding Zhi Pills described in "Thousand-Golden-Prescriptions" have better memory improving effect than those described in "Prescriptions People's Welfare Pharmacy". A combination of Poria, Radix Polygalae and Rhizoma Acori Graminei could enhance the pharmacologic effect of Radix Ginseng. Cinnabaris, described in "Prescriptions People's welfare Pharmacy", as one of the compositions in Ding Zhi Pills, does not improve the impairment of learning and memory, and therefore seems to have no meaning in the Ding Zhi Pills.

Animals↗
PubMed1995

Arginine vasotocin injection increases probability of calling in cricket frogs, but causes call changes characteristic of less aggressive males.

Male cricket frogs, Acris crepitans communicate to males and females using advertisement calls, which are arranged into call groups. Calls at the middle and end, but not beginning of the call group, are modified in response to male-male aggressive interactions. We found in this field study of male cricket frogs in natural breeding choruses that the peptide hormone arginine vasotocin (AVT) not only increased the probability that males called after injections, but also caused modifications in middle and end calls to produce calls characteristic of less aggressive males. Moreover, AVT-injected males showed significantly greater increases in call dominant frequency than saline-injected males, again, a characteristic of less aggressive males. Cricket frog calls are used to both repel males and attract females, thus call changes may relate to male-male and/or male-female interactions. Saline-injected males also demonstrated significant changes in several call traits, including changes that occurred in the beginning and middle calls of the call groups, but not the end calls. AVT appeared to block some call changes produced through handling. These data suggest that AVT can influence acoustic communication in frogs in several ways, including effects on call characteristics and dominant frequency, as well as potentially blocking some handling effects.

Aggression↗
PubMed1995

Medical student exposure to blood and infectious body fluids.

Few data assess the exposure of students to blood or other potentially infectious body fluids during medical school. Fourth-year medical students completed a written survey immediately before graduation describing exposures during their last 2 years. Nearly one half of all graduating students recalled at least one exposure, with only 40% of these exposures reported to supervising house staff or faculty. Clerkships with the highest exposure rates were emergency medicine, surgery, and obstetrics-gynecology.

Blood-Borne Pathogens↗
PubMed1995

Chemoprevention of cervical cancer with folic acid: a phase III Southwest Oncology Group Intergroup study.

Several epidemiological reports and experimental investigations have suggested a preventive role for folic acid in the etiology of cervical cancer. The effect of p.o. folic acid supplementation on the natural history of cervical intraepithelial neoplasia (CIN) was evaluated in a multiinstitutional prospective, randomized, double-blind, placebo-controlled trial. Three hundred thirty-one women with biopsy-proven koilocytic atypia, mild CIN, or moderate CIN were randomized to receive oral folic acid (5 mg) or a similar-appearing placebo daily for 6 months following a 1-month run-in placebo period. Colposcopy, Papanicolaou smear, and serum vitamin levels (folate, retinol, alpha-tocopherol, beta-carotene, and retinyl palmitate) were monitored every 3 months. Demographic, medical, dietary, and sexual history data were obtained from personal interviews. The primary end point of the study was improvement in both Papanicolaou smear and colposcopic picture after 3 and 6 months of treatment as compared to the start of treatment. After 6 months of treatment there was no significant difference between the two study groups in the percentage of patients improved. Median serum folate levels in the treatment arm at 3 and 6 months (29.0 and 20.0 micrograms/dl) were significantly higher than those in the placebo arm (7.8 and 7.1 micrograms/dl, respectively). Mean serum levels of retinol, retinyl palmitate, alpha-tocopherol, and beta-carotene did not differ significantly between the two treatment arms. Our data support the conclusion that supplementation with folic acid (5 mg/day) does not enhance the regression of early epithelial abnormalities of the cervix.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

[Analysis of human DNA fingerprints by using fluorescein labelled probe JH12.6].

A method of analysis of human DNA fingerprints has been established by using fluorescein (Fl-11-dUTP) labelled probe JH12.6. The clear and high distinctive patterns of human DNA fingerprints were obtained with this method. The DNA fingerprints of 78 unrelated individuals living in Yunnan province of China were detected, and their probability of chance association between random individuals was calculated as 7.4 x 10(-11), and their mean allelic frequency as 0.09. Comparing of DNA fingerprints with labelling probe JH12.6 by using between radioactive 32P and fluorescein showed that the method by using fluorescein labelled probe JH12.6 was simple, fast, safe and economical. It can totally replace the method by using radioactive 32P labelled probe JH12.6, and it can be broadly applied in forensic medicine and other fields.

DNA Fingerprinting↗
PubMed1994

Gou-teng (from Uncaria rhynchophylla Miquel)-induced endothelium-dependent and -independent relaxations in the isolated rat aorta.

Gou-teng is a drug used for treatment of hypertension in Chinese medicine. Its antihypertensive action has been previously confirmed in the spontaneously hypertensive rat (SHR). Here, its vasorelaxing effect and the mechanisms of actions were studied in vitro. Gou-teng extract (GTE) relaxed the norepinephrine (NE)-precontracted aortic ring preparations isolated from Wistar Kyoto rats (WKY) with and without intact endothelium; the latter was significantly less sensitive than the former. The GTE-induced endothelium-dependent relaxation was significantly inhibited by NG-monomethyl-L-arginine (NMMA) in a dose-dependent manner while indomethacin did not affect the relaxation. Atropine inhibited the acetylcholine (ACh)-induced endothelium-dependent relaxation but did not the GTE-induced one. Furthermore, once GTE was applied, the following NE-induced contraction was significantly reduced even after repeated washout. NMMA effectively reduced and rather reversed this residual effect of GTE. From these results, it is concluded that GTE relaxes the NE-precontracted rat aorta through endothelium-dependent and, to lesser extent, -independent mechanisms. The endothelium-dependent component would be mediated by EDRF/NO pathway in which the muscarinic cholinoceptors were not involved. Thus, GTE appears to be a potent and long-lasting vasodilator mainly through EDRF/NO release.

Acetylcholine↗
PubMed1994

Hormonal factors in vulvar cancer. A case-control study.

As part of a case-control study of vulvar cancer, we examined the role of reproductive history, menstrual history, exogenous estrogen use and body mass in the etiology of this disease. A total of 330 women with vulvar squamous cell cancer (259 in situ, 81 invasive), aged 18-79 years, who were diagnosed with this tumor during 1980-1990 were interviewed. Their responses were compared to those of 1,010 women who were selected from the general population by means of random digit dialing. Cases and controls did not differ regarding age at menopause, parity, number of prior pregnancies or number of prior births, history of miscarriage or use of noncontraceptive estrogens. Women diagnosed with vulvar cancer were slightly more likely to have experienced menarche at < 12 years (odds ratio [OR] = 1.8, 95% confidence interval [CI] = 1.2-2.7, in situ cancer; OR = 1.6, 95% CI = 0.8-3.1, invasive cancer), to have excess weight (invasive cancer only, OR = 2.9, 95% CI = 1.5-5.8 for highest tertile of Quetelet's index) and, among gravid women, to have had their first pregnancy after age 24 (in situ cancer only, OR = 1.5, 95% CI = 0.9-2.5). These data, together with similar results from previous studies and quantitative studies of hormone receptors in vulvar tissue, suggest that in situ and invasive vulvar cancer are not strongly hormone dependent tumors.

Adolescent↗
PubMed1993

Tissue distribution of succinylacetone in the rat in vivo: a possible basis for neurotoxicity in hereditary infantile tyrosinemia.

Neurologic dysfunction is a significant component of hereditary infantile tyrosinemia, an autosomal recessive disorder of man. The specific enzyme defect leads to endogenous production of the biochemical marker compound, succinylacetone (SA). Earlier study of the role which SA plays in generation of the renal Fanconi syndrome, also associated with this disorder, led to speculation that SA might also have neurotoxic effects. Thus, we have studied the distribution and impact on heme metabolism of SA in brain, liver and kidney from rats treated in vivo. Our results show far greater retention of SA in brain and kidney than in liver, by a ratio of approx. 3:1. Delta-aminolevulinate dehydratase (ALAD) was reduced to less than 10% of control activity in all three tissues after three daily injections; after a 7-day recovery, activity was regained at different rates in the three tissues. Total heme content of each tissue showed a steady decline beyond the treatment period, the most marked reduction being found in kidney. Porphyrin intermediates, heme oxygenase activity and cytochrome P-450 content evidenced varying responses to SA exposure which differed from tissue to tissue. Our results show that brain tissue sequesters SA and that heme biosynthesis in brain, as distinct from liver and kidney, is adversely affected. Such effects could result in impaired oxidative metabolism in brain, producing the CNS manifestations of tyrosinemia.

Animals↗