Biomedical subjects
Publications and source records attributed to Z Qian.
By two-photon resonant three-photon ionization and two-photon hybrid resonant three-photon ionization in Na2-Na the different ion current strength with different temperature was measured. The result was discussed.
Using PUMS data from the 1980 and the 1990 U.S. Census, I apply log-linear models to examine interracial marriage among whites, African Americans, Hispanics, and Asian Americans. Rarely, but increasingly between 1980 and 1990, interracial marriage of whites occurs most frequently with Asian Americans, followed by Hispanics, and then by African Americans. Interracial marriage tends to be educationally homogamous and the odds of interracial marriage increase with couples' educational attainment. Among interracially married couples with different educational attainments, both men and women from lower status racial groups but with high education levels tend to marry spouses from a higher status racial group with low education levels.
Avian leukemias and lymphomas are caused primarily by retroviruses and herpesviruses. The protooncogenes activated by avian retroviral insertions in B & T-cell lymphomas will be summarized, with discussion on a new common insertion site, bravo, associated with RAV-O LTR insertion. Two novel interactions between avian retroviruses and Marek's disease herpesvirus (MDV) will be described: one involves direct interactions between putative viral oncoproteins and the other integrative recombination between these two viruses.
Hyperacute rejection (HAR) of discordant xenografts is dependent on local complement activation. The formation of a functional complex of the complement components C5b-9 (membrane attack complex, MAC) causes endothelial injury and activation leading to coagulation and inflammation. In PVG rats which selectively lack the C6 component of complement, the MAC complex is not formed, whereas early split products of the complement cascade are produced normally. We reported previously that HAR is averted in C6 deficient xenograft recipients, and that subsequent accelerated acute rejection (AAR) can be delayed by inhibition of CD11b/CD18 (Mac-1) dependent neutrophil adhesion using leumedin, a member of a novel class of anti-inflammatory agents. Here we report the in vivo effects of a dose-response study using 2 new members of another class of Mac-1 directed agents designated nactins. Discordant cardiac xenografts from Hartley guinea pigs were heterotopically grafted into PVG(C6-) and PVG(C6+) rats. Experimental animals were divided into 3 groups receiving leumedin (group 1) or nactin (groups 2 and 3). Control animals received intravenous saline solution only. All C6(+) rats rejected their grafts hyperacutely within 10 to 15 min, irrespective of mode or dosage of treatment. C6 deficient controls rejected grafts within 17.7 +/- 3.5 h (n = 10). Treatment with leumedin/nactin prolonged graft survival up to 61.0 +/- 4.7 h (n = 4-6), with dose dependent differences in effectiveness among the 3 compounds tested. Histology showed that treatment was associated with less edema, hemorrhage, and neutrophil infiltrate at 2, 6, and 12 h. The marked decrease in hemorrhage seen in nactin-treated animals may reflect an interaction of Mac-1 with blood coagulation factors. Our data confirm that the neutrophil adhesion pathway is involved in AAR, especially when complement mediated injury due to MAC is restricted.
This study analyzes ethnic differences in induced abortion among ever-married women in Kazakstan, drawing on data from the 1995 Kazakstan Demographic and Health Survey. Instead of conventional ethnic markers, such as "Kazak" or "Russian," it focuses on more complex ethnocultural identities that combine ascribed ethnicity with language use. Because of the history of russification in Kazakstan, three ethnocultural groups are defined and compared--Kazak women who chose to be interviewed in Kazak, Kazak women who chose to be interviewed in Russian, and women of European background interviewed in Russian. Whereas women of European origin were the most likely to undergo induced abortion, the Russian-interviewed Kazaks had higher abortion ratios and were more likely to terminate their pregnancies than were the Kazak-interviewed Kazaks, net of other characteristics. The implications of the results for induced abortion trends and family planning policy in Kazakstan are discussed in addition to other findings.
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Levels of plasma vitamin C and E (P-VC, P-VE), beta-carotene (P-beta-Car), lipoperoxides (P-LPO), and activity of erythrocyte superoxide dismutase (E-SOD) were measured in 871 healthy smokers and 348 healthy non-smokers to study the relationship between cigarette smoking and antioxidant vitamins and oxygen free radicals. Results showed that levels of P-VC, P-VE, P-beta-Car and E-SOD reduced significantly, and level of P-LPO increased significantly in smokers, as compared with those in non-smokers. Levels of P-VC, P-VE, P-beta-Car and E-SOD reduced and level of P-LPO increased in 65 male smokers at the same age, with the increase of duration of smoking and quantity of cigarettes smoked, showing a linear correlationship. It suggested that there existed serious imbalance between oxidation and antioxidation in the bodies of smokers, and oxygen free radical reaction and reaction of lipoperoxidation obviously intensified.
Fifty seven cases of oral squamous cell carcinoma (SCC) were studied by immunohistochemical ABC method using type IV collagen and laminin antibody to investigate the relationship between expression and distribution of basement membrane in oral SCC and clinicopathologic characteristics and cervical lymph node metastasis. The distribution of basement membrane of oral SCC was discontinuous and in some cases the membranes disappeared. There was highly significant correlation between the staining patterns together with histologic differentiation degrees and cervical lymph node metastasis (P < 0.05). These indicate that the expression of baasement membrane in oral SCC may be a useful parameter for evaluation of tumor histologic differentiation and tumor invasion and metastasis.
Biotinylated microcystin was used to affinity purify over avidin-Sepharose the entire cellular content of active forms of protein phosphatase (PP) 1 and 2A holoenzymes present in three subcellular fractions of skeletal muscle. Biotinylated microcystin displayed IC50 values in the nM range against PP-1C (1.58 +/- 0.6 nM S.E., n = 3), PP-2AC (0.63 +/- 0.2 nM S.E., n = 3) and SMPP-1M (5.9 +/- 1.3 S.E., n = 3). Subsequent anion-exchange chromatography and SDS-polyacrylamide gel electrophoresis of the microcystin-biotin eluates of the three fractions revealed a complex pattern of proteins associated with PP-1C and PP-2AC. Far Western analysis and the rebinding interaction with recombinant PP-1C distinguished proteins in the eluates that bound PP-1C from those that bound PP-2AC. In Far Western analysis, 29 distinct proteins were identified to bind PP-1C. Significantly, these same proteins, plus seven others, were also recovered from the isothiocyanate eluates from microcystin-Sepharose by a rebinding interaction with PP-1C-microcystin-biotin. The number of proteins and range of novel molecular masses (18-125 kDa) identified to interact with PP-1C by these two techniques cannot be accounted for by the previously characterized subunits of PP-1. Our findings further support the concept that PP-1C is regulated in vivo by multiple and distinct substrate-targeting subunits.
Biochemical studies indicate that the Drosophila timeless protein (Tim) is a stoichiometric partner of the period protein (Per) in fly head extracts. A Per-Tim heterodimeric complex explains the reciprocal autoregulation of the proteins on transcription. The complex is under clock control, and many circadian features of the Tim cycle resemble those of the Per cycle. However, Tim is rapidly degraded in the early morning or in response to light, releasing Per from the complex. The Per-Tim complex is a functional unit of the Drosophila circadian clock, and Tim degradation may be the initial response of the clock to light.
Ultrasonic irradiation at 500 kHz and 10 mW cm-2 of a 24 h old biofilm of P. aeruginosa enhanced the killing of bacteria by gentamicin. To determine whether this bioacoustic effect was caused by ultrasonic-induced changes in the biofilm morphology (biofilm breakup or disruption), the biofilms were examined by confocal scanning laser microscopy (CSLM). Such disruption would be undesirable in the possible ultrasonic treatment of implant infections. The CSLM results showed that the biofilm is a partial monolayer of cells with occasional aggregates of cells, non-cellular materials and extracellular spaces. The aggregates contained large amounts of exopolysaccharide. The structure of biofilm was not changed when the biofilm was exposed to continuous ultrasound at 500 kHz and 10 mW cm-2, the same irradiation parameters that increased cell killing by nearly two orders of magnitude. The observation that low-intensity ultrasound does not disrupt biofilm or disperse the bacteria has significance in the possible use of ultrasound to enhance the action of antibiotics against biofilms.
Marek's disease virus is a highly oncogenic herpesvirus that can cause T lymphomas and peripheral nerve demyelination in chickens. meq, a candidate oncogene of Marek's disease virus, encodes a basic leucine zipper (bZIP) transcription factor which contains a large proline-rich domain in its C terminus. On the basis of its bZIP structural homology, meq is perhaps the only member of the jun-fos gene family completely viral in origin. We previously showed that Meq's C-terminal domain has potent transactivation activity and that its bZIP domain can dimerize with itself and with c-Jun also. In an effort to identify viral and cellular targets of Meq, we have determined the optimal binding sites for Meq-Jun heterodimers and Meq-Meq homodimers. By a PCR-based approach using cyclic amplification of selected targets, Meq-Jun heterodimers were found to optimally bind tetradecanoylphorbol acetate response element (TRE) and cyclic AMP response element (CRE) consensus sequences. This result was consistent with the results of our previous functional analysis implicating Meq-Jun heterodimers in the transactivation of the Meq promoter through a TRE- or CRE-like sequence. Interestingly, Meq-Meq homodimers were found to bind two distinct motif elements. The first [GAGTGATG AC(G)TCATC] has a consensus which includes a TRE or CRE core flanked by additional nucleotides critical for tight binding. Methylation interference and mutational analyses confirmed the importance of the flanking residues. The sequences of a subset of TRE and CRE sites selected by Meq-Meq are closely related to the binding motif of Maf, another bZIP oncoprotein. The second putative Meq binding site (RACACACAY) bears a completely different consensus not shared by other bZIP proteins. Binding to this consensus sequence also requires secondary structure characteristics associated with DNA bending. CACA motifs are known to promote DNA curvature and function in a number of special biological processes. Our results lend further weight to the increasing importance of DNA bending in transcriptional regulation and provide a baseline for the identification of Meq-responsive targets.
We conducted a case-control study of the possible association of occupations with likely exposure to electromagnetic fields and Alzheimer's disease (AD) with patients from the Alzheimer Disease Treatment and Diagnostic Center, Rancho Los Amigos Medical Center, Downey, CA. Patients with definite or probable AD were the case subjects (86 male, 240 female). Patients with cognitive impairment/dementia other than vascular dementia were control subjects (76 male, 76 female). The study was limited to patients who were at least age 65 at the time of their first examination at Rancho Los Amigos. The odds ratio for both sexes combined was adjusted for sex, education, and age at onset. The odds ratio for males was adjusted only for age at onset, and the odds ratio for females was adjusted for both education and age at onset. The adjusted odds ratio for both sexes was 3.93 (p = 0.006), 95% CI = (1.5 to 10.6). For males the adjusted odds ratio was 4.90 (p = 0.01), 95% CI = (1.3 to 7.9), and for females the adjusted odds ratio was 3.40 (p = 0.10), 95% CI = (0.8 to 16.0). These results are consistent with previous findings regarding the hypothesis that electromagnetic field exposure is etiologically associated with the occurrence of AD.
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OBJECTIVE: To establish a method for localization and qualitative diagnosis of glioma. METHODS: The monoclonal antibody SZ-39 against human glioma was labelled with 131I and injected intravenously into 40 patients with intracranial occupying lesions proved by X-CT. 72 hours after 131I-McAb-SZ39 administration, cranial bone nuclide-imaging agent 99mTc-MDP was injected intravenously, and the patients were examined by SPECT scan with dual nuclide double channel tomography and special software. On radio-immuno-image, the immunocomplex formed by specific conjugation of 131I-McAb-SZ39 with target tissue was red, while the cranial bone incorporated with 99mTc-MDP was green. The location of the immunocomplex area could be identified by the superimposition of the images. RESULTS: 21 patients with positive targeting diagnosis of glioma showed the accuracy rate checked by SPECT was 81%(17/21) and by X-CT 48% (10/21). Seven patients with negative targeting diagnosis showed the accuracy rate checked by SPECT was 86%(6/7) and by X-CT 14% (1/7). Pathologically, the sensitivity of targeting SPECT to glioma was 94.5%(17/18) and that of X-CT 55%(10/18). CONCLUSIONS: Targeting SPECT examination could be used for localization and qualitative diagnosis of glioma and make up the inadequacy of X-CT in the qualitative diagnosis of atypical incipient and recurrent glioma, meningioma, metastatic carcinoma, and inflammatory lesions of brain.
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The recombinant oncotoxin AR209 [e23(Fv)PE38KDEL; formerly OLX-209] was developed to treat neoplasia that expresses the c-erbB-2 (HER-2/neu) protein product p185(erbB-2). The AR209 compound contains a single-chain antibody domain specific for p185(erbB-2), coupled with a portion of the Pseudomonas exotoxin. The drug has been shown to be effective in inhibiting cells that overexpress erbB-2 due to gene amplification and in cells that do not contain amplified erbB-2 but express slightly higher levels of the protein than normal cells do. To test the efficacy of AR209 on human lung tumors, athymic nude mice were inoculated intrathoracically with a cell line derived from a poorly differentiated lung adenocarcinoma. This cell line, termed 201T, expresses moderately elevated levels of p185(erbB-2) 7.6-fold over normal bronchial epithelium. Mice treated with i.v. injections of AR209 for 5 weeks after orthotopic tumor implantation had smaller tumors and in 20% of cases showed no evidence of disease. The data from this study indicate that AR209 may be an effective treatment for patients with non-small cell lung cancers that express p185(erbB-2).