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Biomedical subjects

Y G Zhang

Publications and source records attributed to Y G Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1995

Forensic pathological expertise of medical tangle analysis of 139 autopsy cases.

In this article, we report 139 autopsy cases of medical tangle, which were examined by the Department of Forensic Pathology, Faculty of Medicine, Tongji Medical University from Jan. 1972 to Dec. 1992. The emphasis is put on analyses of the status of medical tangle autopsy in forensic pathology, involved medical departments, distribution of victim's age and sex, differences between clinical diagnosis and autoptical conclusion, the composition and causes of medical tangle. The associated problems in forensic pathological autopsy are also discussed.

Adult↗
PubMed1994

Use of bremsstrahlung radiation to monitor Y-90 tumor and whole body activities during experimental radioimmunotherapy in mice.

BACKGROUND: Large differences in uptake between tumors, even for the same size, frequently observed in clinical and experimental radioimmunotherapy (RAIT), make monitoring of uptake in individual tumors imperative in comparing protocols. 90Y, widely-used for RAIT, emits no gamma radiation and absorption of the beta particle in tissue makes its detection unsuitable for in vivo monitoring. We tested whether bremsstrahlung radiation, produced when betas are decelerated by nuclei, could be used to monitor tumor uptake. METHODS: Subcutaneous human LS174T colon carcinoma tumors were grown in the upper thigh of nude mice and labeled antibody injected intracardially. With the tumor placed in the 2 cm-diameter aperture in a lead collimator, photons with energies from 100 to 200 keV transmitted through plastic, which absorbed the beta particles, were counted to maximize shielding from the rest of the body. The contribution of the normal tissues was subtracted by counting the non-tumor-bearing leg in the same position. Excretion was calculated from whole body activity determined by removing the collimator, placing the mouse in a syringe surrounded by tissue-equivalent material 10 cm from the detector, and counting photons between 200 and 740 keV to minimize the effect of tissue attenuation. RESULTS: For tumors larger than 0.14 gm, a good correlation was obtained between the in vivo bremsstrahlung measurements and the measurements on excised tumors in a calibrated well counter. Similar excretion rates observed in all the animals suggested that the whole body counting was accurate. CONCLUSIONS: Bremstrahlung detection appears feasible and reliable for monitoring both tumor and whole body activities.

Animals↗
PubMed1994

A new method for determining dose rate distribution from radioimmuno-therapy using radiochromic media.

PURPOSE: To describe and evaluate a new, simple, inexpensive method for directly measuring the radiation dose and its spatial distribution generated from explanted tissues of animals previously injected with radiolabeled immunoconjugates or other agents. METHODS AND MATERIALS: This technique uses the newly developed radiochromic dye medium (Gafchromic) which responds reproducibly for therapeutic dose exposures, has high spatial resolution, does not require film processing, and is relatively insensitive to ambient light. We have evaluated the dose distribution from LS174T tumors and selected normal tissues in nude mice previously injected with 90Y labeled anti-carcinoembrionic antigen antibodies. Individual tissues from sacrificed animals are halved and the flat section of the tissue is placed onto the dosimetry media and then frozen. The dosimetry medium is exposed to beta and Bremsstrahlung radiation originating from the frozen tissues. The relative darkening of the dosimetry medium depends on the dose deposited in the film. The dosimetry medium is scanned with a commercial flatbed scanner and the image intensity is digitally stored and quantitatively analyzed. Isodose curves are generated and compared to the actual tissue outline. RESULTS: The absorbed dose distribution due to 90Y exposure show only slight gradients in the interior of the tissue, with a markedly decreasing dose near the edges of the tissue. In addition, the isodose curves follow the tissue outline except in regions having radii of curvature smaller than the range of the beta-particle (R90 = 5 mm). These results suggest that the shape of the tumor, and its curvature, are important in determining the minimum dose delivered to the tumor by radiation from 90Y monoclonal antibodies, and hence in evaluating the tumor response to the radiation. The dose and spatial dose distribution were calculated assuming that the total 90Y activity is distributed uniformly throughout a half ellipsoid. The calculated spatial dose distributions for the half ellipsoids were similar to those observed from the dosimetry media that had been exposed to radioactivity contained in the tumors. CONCLUSION: This method provides direct dose evaluation without elaborate summary calculations based on activity measurements from serial slices. The measured radiation dose actually indicates the dose rate at the time of animal sacrifice. Quantitative analysis of radiation emitted from the tissues is relatively fast, making it feasible to examine a number of tissues under a variety of conditions.

Animals↗
PubMed1994

Effects of Panax notoginseng saponins on myocardial adenosinetriphosphatase.

Effects of total Panax notoginseng saponins (PNS) and Panax notoginseng saponin monomers Rb1 and Rg1 (Rb1, Rg1) on total ATPase and Na(+)-K(+)-exchanging ATPase of guinea pig heart were studied. It was found that PNS inhibited the total myocardial ATPase, but had no significant effect on the myocardial Na(+)-K(+)-exchanging ATPase. The total ATPase was inhibited by Rg1, and more clearly by Rb1. The automaticity and contractility of isolated guinea pig atria were inhibited by Rb1. Rg1 decreased the spontaneous frequency of isolated guinea pig right atrium, but not markedly the contractility of the left atrium. These results demonstrate that Rb1 is the main ingredient in PNS.

Adenosine Triphosphatases↗
PubMed1994

[The use of color Doppler flow imaging in diagnosis and differential diagnosis of some pulmonary masses].

The status of blood supply was examined in twenty-nine patients with pulmonary masses with color doppler flow imaging. The results showed that there are no significant blood signals in 5 benign masses. One patient with pulmonary arterio-venous fistula can be diagnosed. Pulmonary inflammatory pseudotumor and 20 lung cancers have rich blood supply. The peak forward velocity and resistance index between them have obvious difference statistically (P < 0.05, P < 0.01). It is concluded that color doppler can be regarded as an useful and noninvasive method before operation in diagnosing some pulmonary masses.

Adult↗
PubMed1993

[Clinical investigation of erythrocyte function in patients with lung cancer].

With a yeast-erythrocyte-SPA rosette method, the function of erythrocyte immune adherence was determined in 49 cases of lung cancer, 20 cases of benign pulmonary diseases and 60 healthy persons. By means of simple morphologic method and pyrogallol autoxication method, the function of erythrocyte enhancing neutrophils phagocytosis and the activity of RBC-CuZnSOD were measured in some of these subjects. It was found that both the function of red cell immune adherence and the effect of erythrocyte enhancing phagocytosis in the patients with lung cancer were significantly weaker than in the cases of benign pulmonary diseases and the healthy subjects. The function of erythrocyte immune adherence tended to recover after effective surgical treatment. In comparison with the healthy persons, the activity of RBC-CuZnSOD was significantly lower in the patients with lung cancer. The mechanism and clinical significance of the changes in erythrocyte function were discussed.

Adult↗
PubMed1993

[Studies on diterpenoids from leaves of Tripterygium wilfordii].

Tripterygium wilfordii Hook f. has been used as a medicinal herb in traditional Chinese medicine and as an insecticide by the Chinese for hundreds of years. Recently, this plant has been used to treat cancer, rheumatic arthritis and various skin diseases in some Chinese clinics. It is of interest to note that Tripterygium also showed significant antifertility activities. The active principles of the anti-inflammatory, immunosuppressive and antifertile actions in Tripterygium are diterpenoid containing triepoxides, but information on its chemistry is limited to the woody part of the root and the root bark. Recently, we have studies the leaves of Tripterygium (collected at Zhejiang province, China), and isolated two novel diterpenoids by chromatography named tripdioltonide (8) and 13,14-epoxide 9,11,12-trihydroxytriptolide (9), besides triptonide (1), triptolide (2), tripdiolide (3), triptolidenol (4), 16-hydroxyl-triptolide (5), tripchlorolide (6) and triptriolide (7). Their structures were established by chemical reactions, TLC, UV, MS, IR, 1H-1H COSY, 1H-13C COSY, DEPT spectrometric investigation. The structure of tripdioltonide was further confirmed by X-ray analysis.

Diterpenes↗
PubMed1993

[Mixed keratinocyte culture and its composite skin graft].

We overlaid sheets of autogenous, allogeneic or mixed keratinocyte culture on allogeneic dermis to form 3 types of composite skin to cover full-thickness skin wounds, and observed their rates of survival. Both the autogenous and mixed keratinocytes culture took well, and no signs of rejection were observed. Their morphology and function appeared the same as normal skin. Cultured allogeneic keratinocyte sheets showed lower survival rate than the autogenous and mixed sheets, and they were rejected in two weeks. By examining the sex chromosome of mixed keratinocytes sheets, which have been grafted for 14 or 21 days, it was found that the allogeneic keratinocytes were progressively replaced by autogenous keratinocytes. From the above results, we think that the advantages of using mixed keratinocytes culture are that it took shorter time to obtain a clinically useful cell sheet, and it takes well without obvious rejection. We believe that it can be used to cover permanently large burn wounds.

Animals↗
PubMed1992

Sensitization processes in human tumor cells during protracted irradiation: possible exploitation in the clinic.

Recent studies documenting the response of several human tumor cell lines to protracted, continuous irradiation and to acutely delivered radiation, suggest that tumor control may be enhanced with a tumor therapy combining external beam fractionated therapy and protracted irradiation from radiolabeled antibodies. We have evaluated the cytotoxic effect of continuous, protracted irradiation (0.005 Gy/hr to 0.50 Gy/hr) and acutely delivered high-dose-rate irradiation (1.0 Gy/min) on monolayer cultures of human tumor cell lines. Colony formation in these studies was analyzed by the seven-parameter simulation model of Dillehay. Additionally, for some cell lines, cultures were challenged during irradiation with an acute dose of 2.5, 5.0, 7.5 or 10.0 Gy at high-dose-rate. Results from these various studies indicate an altered cellular radiosensitivity occurs for some cell lines during protracted irradiation. At least two mechanisms have been identified that underlie this altered radiosensitivity. One mechanism, G2B, associated with redistribution within the cell cycle, has been previously described by Mitchell and others, and is associated with the phenomenon termed "the inverse dose-rate effect". The other mechanism is only observable following a challenge by acute high-dose-rate irradiation. We have termed this phenomenon "protracted-exposure-sensitization." The characteristics of these two mechanisms are discussed from the perspective of clinical therapeutic exploitation of combined external beam fractionated therapy and radiolabeled immunoglobulin therapy.

Cell Cycle↗
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↗
PubMed1991

Characteristics of bronchial hyperresponsiveness in chronic obstructive pulmonary disease and in asthma.

By studying the characteristics of BHR in subjects clearly defined as having asthma or COPD, it is apparent that there are both similarities and differences. These responses can be broadly explained in terms of present knowledge of the pathologic features and the mechanisms causing the abnormalities in the two diseases, and they highlight the important differences between the diseases. It seems likely that tests of BHR with histamine and methacholine cannot be used to distinguish asthma from COPD in subjects with a mild decrease in FEV1 and symptoms that do not clearly suggest asthma or COPD. However, a dose-response curve to methacholine is helpful. If there is a plateau, and the PD20 FEV1 is more than 4.0 mumol, it is unlikely to be asthma. If there is no plateau, a test with propranolol or SO2 may be useful to discriminate the two diseases. The similarities in the responses-especially those to histamine-explain why there is frequently difficulty in deciding the nature of the disease present in an individual subject. Is it important to distinguish the two diseases? In the introduction it was suggested that it is important for understanding these diseases, for prognosis, for treatment, and ultimately for prevention. It remains difficult to determine prognosis from any single test of bronchial responsiveness, and response to prophylaxis (stopping smoking, allergen avoidance) plus drug treatment over several years is probably needed to predict outcome in an individual patient. Finally, despite the valid hypothesis proposed by Orie and coworkers (2), it seems unlikely that studying the characteristics of BHR will shed light on the "host" factors present in both diseases that remain poorly understood.

Asthma↗
PubMed1990

Epidemiological and aetiological evidence for transmission of Lyme disease by adult Ixodes persulcatus in an endemic area in China.

Involvement of adult Ixodes persulcatus ticks in the transmission of Lyme disease in Hailin County, Heilongjiang Province, China, is reported. In 1986 from April through August adult I. persulcatus was the dominant tick in this endemic area with an infection rate of 43% for the Lyme disease spirochaete, Borrelia burgdorferi. The incidence of Lyme disease cases presenting the symptom of erythema chronicum migrans (ECM) within this area was correlated with the seasonal abundance of adult I. persulcatus and the number of people bitten by ticks. The frequency of ECM formation in all age groups varied and was associated with the frequency of tick bites. In addition, a strain of B. burgdorferi was isolated from a pool of six female I. persulcatus collected from this area. We demonstrate that the seasonal abundance of adult I. persulcatus and its frequent attachment to humans result in the spring and summer transmission of Lyme disease in this endemic area. The role of immature I. persulcatus in Lyme disease transmission is apparently minimal.

Adolescent↗
PubMed1990

Effect of inhaled preservatives on asthmatic subjects. I. Sodium metabisulfite.

Sodium metabisulfite (MBS) is used as a preservative in food and wine and frequently triggers attacks of asthma. To determine the characteristics of responses to inhaled MBS, 30 asthmatic subjects and 16 nonasthmatic subjects inhaled MBS, in concentrations of 6.2, 12.5, 50, and 100 mg/ml, from a DeVilbiss No. 40 nebulizer (DeVilbiss Co., Somerset, PA) in doses ranging from 0.1 to 12.8 mumol. Response was measured as the dose that caused a 20% fall in FEV1 (PD20FEV1). All the asthmatic subjects responded; one of the atopic, nonasthmatic subjects responded and none of the nonatopic, nonasthmatic subjects responded. The response occurred within 1 min, and most subjects recovered to within 10% of baseline after 30 to 40 min. Dose-response curves to MBS were steep and were reproducible, within a 7-day period, to within one doubling dose, with mean PD20FEV1 values of 2.17 and 2.11 mumol in 11 subjects. There was no correlation between PD20FEV1 values to MBS and histamine, and inhalation of MBS did not enhance responses to subsequent challenge with histamine (mean PD20FEV1 to histamine was 0.65 mumol and to histamine 1 h after MBS was 0.74 mumol). Challenge with MBS (mean PD20FEV1 4.07 mumol) did not cause refractoriness to a second challenge 1 h later (mean PD20FEV1 5.39 mumol). Of 20 subjects tested, prior inhalation of 8 mg nedocromil sodium blocked the response to MBS in 15 subjects and reduced it in two others. Cromolyn sodium (4 mg) blocked the response to MBS in three subjects but did not alter the mean PD20FEV1 in the remaining 17 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Effect of inhaled preservatives on asthmatic subjects. II. Benzalkonium chloride.

Benzalkonium chloride has been used as a preservative in some antiasthma respirator solutions and is known to cause bronchoconstriction in asthmatic subjects. To increase understanding of how it causes bronchoconstriction, the characteristics of airway response in 28 asthmatic subjects were documented. Subjects inhaled histamine, in doses ranging from 0.03 to 7.8 mumol, or benzalkonium in doses ranging from 0.04 to 5.33 mumol on separate days. The dose of histamine or benzalkonium that caused a 20% fall in the 1-s forced expiratory volume (PD20FEV1) was measured. All subjects responded to histamine, with PD20FEV1 values in the range of 0.14 to 7.8 mumol and 17 responded to benzalkonium, with PD20FEV1 values in the range 0.35 to 5.55 mumol. Subjects who responded to benzalkonium were more sensitive to histamine (mean PD20FEV1 0.44 mumol) than subjects who did not respond (mean PD20FEV1 1.84 mumol) and, among the benzalkonium responders, there was a significant correlation between PD20FEV1 values for histamine and benzalkonium (r = 0.5, p less than 0.05). Inhalation of benzalkonium enhanced subsequent responses to histamine, causing a decrease in mean PD20FEV1 from 0.51 to 0.18 mumol histamine (p less than 0.001), but did not alter subsequent responses to benzalkonium. The response to benzalkonium reached a maximum 1 min after inhalation and was slow to recover, taking up to 60 min to return to baseline values. Response to benzalkonium was inhibited by 8 mg cromolyn sodium but not by 160 micrograms ipratropium bromide. The characteristics of the response to benzalkonium suggest a mechanism of action via release of mediators.

Adult↗
PubMed1990

[Effects of trihexyphenidyl on basilar artery of rabbits and cerebrovascular circulation of rats].

Trihexyphenidyl (Tri) inhibited the contraction of rabbit basilar artery due to high K+ (45.6 mmol/L). IC50 was 2.9 +/- 0.7 mumol/L. The contractions of basilar and mesenteric arteries due to calcium and those of basilar artery and saphenous vein due to serotonin were noncompetitively. Tri inhibited myogenic activities of the portal vein strips of rats and increased the normal cerebral blood flow of rats to 19 +/- 7 ml/(min.100 g).

Animals↗
PubMed1989

[The isolation and structure identification of triptotriterpenic acid C].

A new ursolic-type acid named triptotriterpenic acid C was obtained from the total glycosides extracted from the root of Tripterygium wilfordii Hook.f. Its structure was inferred from chemical reaction, IR, 1HNMR, 13CNMR and MS spectral data. The structure and stereochemistry of this compound was confirmed to be 3 beta,22 alpha-dihydroxy-delta 12-ursene-30-oic acid by X-ray crystallo-diffraction analysis of its methyl ester.

Chemical Phenomena↗