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Biomedical subjects

J Q Chen

Publications and source records attributed to J Q Chen.

At least 55 records · Page 3Linked to original sources
PubMed1992

A nested case-control study of lung cancer among silica exposed workers in China.

In an attempt to assess whether silica induces lung cancer, a nested case-control study of 316 male lung cancer cases and 1352 controls was carried out among pottery workers and tungsten, copper-iron, and tin miners from five provinces in south central China. Exposure to dust and silica for each study subject was evaluated quantitatively by cumulative exposure measures based on historical industrial hygiene records. Measurements on confounders such as inorganic arsenic, polycyclic aromatic hydrocarbons (PAHs), and radon were also collected from the worksites. Information on cigarette smoking was obtained by interviews of the subjects or their next of kin. A significant trend of increasing risk of lung cancer with exposure to silica was found for tin miners, but not for miners working in tungsten or copper-iron mines. Concomitant and highly correlated exposures to arsenic and PAHs among tin miners were also found. Risk of lung cancer among pottery workers was related to exposure to silica, although the dose-response gradient was not significant. Risks of lung cancer were significantly increased among silicotic subjects in iron-copper and tin mines, but not in pottery factories or tungsten mines. The results of this study provide only limited support for an aetiological association between silica and lung cancer.

Arsenic↗
PubMed1992

[A preliminary report of epikeratophakia for the treatment of myopia].

Since 1987, 9 cases of high myopia were treated by epikeratophakia with concave corneal lenses shaped by a rapid method on a self-made cryolathe. After the surgery, all patients showed reduced degrees of myopia and astigmatism, with marked improvement in uncorrected visual acuity. The corrected visual acuity was the same as preoperative in 3 cases and improved in 6 cases. No serious complications occurred.

Adult↗
PubMed1992

[Effects of Panax notoginseng saponins on monophasic action potentials of heart and automaticity and contractility of isolated atria].

The effects of Panax notoginseng saponins (PNS) on monophasic action potentials (MAP) recorded from the myocardial surface by means of contact electrode were studied in 30 open-chest rabbits. The MAPA was increased and MAPD50, MAPD90 were prolonged with PNS (100, 200 mg.kg-1, iv), while the Vmax remained unchanged. PNS (300-1200 micrograms.ml-1) inhibited the automaticity of isolated guinea pig right atria and the contractility of the left atria. The positive inotropic action of ouabain (0.2 mumol.L-1) on isolated guinea pig left atria was decreased in the presence of PNS 300 micrograms.ml-1.

Action Potentials↗
PubMed1992

[Studies on antigenic homology between Schistosoma japonicum and Oncomelania hupensis hupensis by indirect immunoperoxidase technique].

Adult Schistosoma japonicum worms and Oncomelania hupensis hupensis tissue sections were employed as antigens in the studies of anti-O. h. hupensis rabbit serum and anti-S. japonicum adult worm rabbit serum by indirect immunoperoxidase assay. The result indicated that the most prominent peroxidase reaction was presented in the adult worm sections and the head-foot and liver sections of O. h. hupensis. These suggested the possible presence of antigenic homology between Schistosoma japonicum and Oncomelania hupenis hupensis. (Figs. 1-7).

Animals↗
PubMed1991

A comparison of pneumoconiosis interpretation between Chinese and American readers and classifications.

As a preliminary step in joint Sino-American pneumoconiosis research efforts, a formal chest X-ray pneumoconiosis reading trial was conducted among Chinese and American radiologists. Twelve Chinese readers from different institutions located in south central China used the 1986 Chinese Roentgenodiagnostic Criteria of Pneumoconioses. Three American radiologists, centified as NIOSH "B" readers, used the International Labour Office Classification of Pneumoconioses. The chest X-ray study set consisted of 150 posterior-anterior films. One-half were Chinese X-rays of silica-exposed workers, and the other half were American films of variously exposed workers but primarily coal miners. All readings were done independently. The results showed that the inter-reader variability among the Chinese was similar to that of the American readers, both being in an acceptable range. In addition, there was general agreement between the Chinese and American interpretations. For small opacity profusion, the Chinese readers tended to read slightly more diseases than their American counterparts, although there was exact agreement as to the major category in two-thirds of the films. Agreement for film quality, and pleural disease was less, but was not different from reported variation among American "B" readers. Overall, the results suggest that despite the use of two different classification systems, a valid correspondence exists between the Chinese and American Interpretations, which is suitable for use in epidemiologic research.

Anthracosilicosis↗
PubMed1991

[The killing effect of hypo-osmolar solutions and hyperthermia on gastric cancer cells MGC-803].

Cells of human gastric cancer cell line MGC-803 after treatment with solutions of different osmolarity, temperature and culture time were injected subcutaneously into nude mice, and the effect of the treatments on tumor growth in vivo was observed. The results showed that cells after treatment with double distilled water, 37-45 degrees C for 10, 20 and 30 minutes did not grow in nude mice, but cells treated with 0.075 M KCl or normal saline did.

Adenocarcinoma, Mucinous↗
PubMed1991

[Effects of morphine on cutaneous blood flow and substance P release evoked by electric stimulation of rat sciatic nerve].

Electric stimulation of the rat sciatic nerve containing sensory afferent fibers produced an increase in cutaneous blood flow. Morphine (10, 30 mumol.kg-1 ia infusion) inhibited the electric stimulation-induced increase of the cutaneous blood flow velocity, and its effect was antagonized by naloxone (2 mg.kg-1 ip). In order to investigate the cause of this effect, we determined immunoreactive substance P (iSP) levels in the sc perfusate of hind paw. We found that electric stimulation of the sciatic nerve led to a significant increase of iSP release into the sc perfusate. Morphine (30 mumol.kg-1 ia infusion) inhibited the electrical stimulation-induced release of iSP, and this effect was completely antagonized by naloxone (2 mg.kg-1 ip). These result suggest that morphine-induced inhibition of the electrical stimulation-evoked increase in cutaneous blood flow could result from inhibition of the release of SP from peripheral sensory nerve endings.

Animals↗
PubMed1991

[A system for intracellular pH recording in cultured cell with ion-selective microelectrode].

An IBM PC/XT compatible microcomputer based system for recording intracellular pH with ion-selective microelectrodes is described. The method for making ion-selective microelectrodes, the designing ideas of the ion-selective microelectrode amplifier and method for improving the accuracy of measurement are addressed. The performance of the system meets the requirements of experiments. Accuracy of measurement, advantages and disadvantages of the system are discussed.

Cells, Cultured↗
PubMed1991

Estimation of entire cardiac left ventricular pressure cycle from brachial arterial pressure during systemic hypoxia.

In functional study of the cardiac pump during systemic hypoxia, noninvasive measurement of the cardiac left ventricular pressure (LVP) during hypoxia is a tempting problem. The authors found from point of view of systems physiology that there existed correlation between brachial arterial blood pressure (BP) and LVP. Using method of normalization and stepwise regression, models were established for estimating LVP upon BP. For the LVP estimated with single hypoxia condition models the average relative area errors e less than 4.3%, with the general hypoxia condition model, e = 5.6%. This approach may be expected to be developed into a method of noninvasive measuring of the LVP.

Animals↗
PubMed1991

[Problems in the surgical treatment of gastric cancers].

Radical resections were performed in 177 cases of gastric cancer (early cancer 31 cases and advanced cancer 146 cases). R+1 operation was performed in 10 cases and R2 or R3 was in 167. All patients were followed up to the end of the study with the 5-year survival rate of 57.6%. In the patients with normal serosa, cancer was often located in the mucosa. In such situation, R1 or R1+ operation was advisable. In the patients of reactive serosal types, the extent of operation should not be reduced. The serosa were often penetrated by cancer cells in diffusely infiltrated cancer, with a poor prognosis. If measures were not taken to destroy free cancer cells, the 5-year survival rate was very low inspite of radical operations. The number of lymph node metastasis was closely related to the biological behavior of primary cancer. Prognosis was good after R2 or R3 operation when the cancer was still within the gastric wall, Borrmann type 1,2,3, massive or nest growth patterns, and the number of lymph node metastasis was below 5 and within first group (n1). If the number of lymph node metastasis was above 10, metastasis to the second (n2) or third group (n3), the cancer infiltrated to the serosa, Borrmann type 4, diffused growth pattern the prognosis was poor even R2 or R3 operations were performed.

Adult↗
PubMed1991

[A report of epikeratophakia for the correction of aphakia].

Epikeratophakia is a new refractive corneal surgery since 1980. The authors treated 30 cases of unilateral aphakia with corneal lenses prepared by a self-made cryolathe. After a mean postoperative follow-up of 161 days, all patients obtained visual improvement. 19 eyes (63.3%) achieved uncorrected visual acuity over 0.5, and 5 eyes (16.7%) were 1.0 or over. 8 eyes (26.7%) were corrected to within 1 diopter by the surgery, and the mean postoperative corneal astigmatism was 2.53 diopters. The complications included over or under correction of the refractive error, interlamellar epithelial ingrowth and opacity. The safety, efficacy and re-operability of epikeratophakia make it a promising technique.

Adolescent↗
PubMed1990

[Effects of 7 drugs on cutaneous blood flow evoked by electric stimulation of rat sciatic nerve].

The non-invasive technique of laser-Doppler flowmeter (LDF) was used to measure the change of cutaneous blood flow evoked by electric stimulation of rat sciatic nerve. The sciatic nerve was cut centrally and placed on bipolar electrodes. Drug were infused in a carotid artery. Electric stimulation of the sciatic nerve containing sensory afferent fibers caused an increase in cutaneous blood flow. This increase was not modified by the ia infusion of adrenergic blocking agents (phentolamine, 0.1 mg/kg and propranolol, 0.5 mg/kg), anti-muscarinic agent (atropine 0.5 mg/kg), anti-histamines (mepyramine, 10 mg/kg and cimetidine, 10 mg/kg) and 5-HT antagonist (methysergide, 0.5 mg/kg). Pretreatment with capsaicin (50 mg/kg, sc) in the newborn rat or the ia infusion of spantide (1, 2 mumol/kg) significantly inhibited the the stimulation-induced increase of the blood flow. These results suggest that substance P released from the peripheral endings of sensory nerve may be involved in vasodilation following electric stimulation of the sciatic nerve in rat.

Analgesics↗
PubMed1990

[Opioid dependence and tolerance in the guinea-pig ileum in vitro].

A rapid and simple method for the quantitative determination of opioid dependence and tolerance in the guinea pig ileum was introduced. Dependence, as indicated by a strong contraction of the ileum when challenged with naloxone, was produced by incubating ileum from native guinea pig with opioid at 37 degrees C for 1-6 h. The response of the ileum to naloxone was time-dependent and directly related to the normorphine concentration in the incubation fluid (10-1000 nmol/L) and to the challenge dose of naloxone (10-1000 nmol/L). There were lower naloxone-precipitated withdrawal responses in the guinea pig ileum incubated with pethidine, nalorphine and ohmefentanyl than with fentanyl, U50488H and morphine. Buprenorphine showed no withdrawal response. In spite of rapid development of dependence, segments of ileum incubated with normorphine at low concentration (10-300 nmol/L) showed no or slight tolerance to normorphine (3-fold). Only by incubating with high concentration of normorphine (1 mumol/L) was high tolerance detected. The results indicate that opioid dependence and tolerance do not develop in parallel.

Analgesics↗
PubMed1989

Physical growth of Chinese children from birth to 6 years old in urban and rural areas in 1985.

During 1985 a survey of the physical growth of 175,290 Chinese children less than 7 years in age was undertaken in the urban and rural areas of ten provinces. The results of weight, height, and head circumference are similar to those generally found as regards the differences between boys and girls. The children in rural areas were lighter and shorter. From the age of 3-6 months onwards the weights and heights of all groups were less than international standards. Nutrition is probably the major factor in these differences in growth.

Body Height↗
PubMed1989

Distribution of substance P and methionine-enkephalin in salivary glands and effect of chronic morphine treatment on levels of these peptides.

Substance P-like immunoreactivity (SPLI) and methionine-enkephalin-like immunoreactivity (MELI) were determined in salivary glands from rats by radioimmunoassay. In all salivary glands investigated (submandibular gland, sublingual gland and parotid gland), SPLI and MELI were detected. The amount of both peptides is comparable to or relatively higher than those found in any other peripheral tissue. The level of SPLI showed a tendency to increase following chronic treatment with morphine: the enhancement in the submandibular gland and the sublingual gland was especially remarkable. The level of MELI was decreased, particularly in the submandibular gland.

Animals↗
PubMed1989

[A preliminary study on diagnosis of schistosomiasis japonica by indirect immunoperoxidase assay using daughter sporocyst-containing Oncomelania tissue sections].

Schistosoma japonicum daughter sporocysts in Oncomelania tissue sections were, for the first time, used as antigen in the diagnosis of schistosomiasis japonica by indirect immunoperoxidase assay (IIPA-DS). The most strong peroxidase reaction was localized on the tegument of the daughter sporocysts and cercariae, and at some parts of cercarial parenchyma, when IIPA-DS was carried out. Of 112 sera from proven cases of schistosomiasis japonica, 106 (94.6%) were positive, the range of titre dilution was from 1:1 to 1:160, the geometric mean of titres was 1:20. IIPA-DS highly coincided with IHA, COP and ELISA in both sensitivity and strength of reaction. Sera from 101 blood donors and 24 normal rabbits were all negative. No cross reaction with sera from 24 patients with paragonimiasis was observed.

Animals↗