Biomedical subjects
Publications and source records attributed to Z Yin.
This paper introduces the method of micro-displacement measurement to improve the space resolution of limited size array detector. This method could also be applied in various research areas, especially in image measurement of nuclear detection.
The glutamine synthetase (EC 6.3.1.2) from the hyperthermoacidophilic crenarcheon Sulfolobus acidocaldarius (DSM 639) was purified to homogeneity, characterized and the glnA gene isolated and sequenced. The amount of enzyme present in the cytosolic fraction from Sulfolobus cells showed a strong variation depending on the carbon and nitrogen sources in the growth medium. The enzyme was found to be a dodecameric protein composed of identical subunits of 52 kDa. It was stable at 78 degrees C in the presence of Mn2+ ions. The catalytic activity was regulated solely by feed-back inhibition through L-alanine and glycine and not by adenylylation. No evidence for the presence of isoenzymes was found. Sequence comparison showed that the Sulfolobus protein is most closely related to the glutamine synthetases of the I-beta type despite its regulatory properties and the finding that the known euryarcheal glutamine synthetase sequences belong to the I-alpha subgroup of these enzymes. Our phylogenetic analysis suggests that the gene duplication leading to the development of the I-alpha and I-beta enzymes preceded the separation of the archea and the bacteria.
The nature and magnitude of the problem of the diversion of prescription drugs from legal to illegal markets have been identified as a high priority by the federal government. This study was based on a random sample (2,005) of declaration forms of persons declaring Mexican prescription drugs at the US Customs office in Laredo, Texas. Of the 75 different types of drugs, the most frequently declared drugs were Valium (71%), Rohypnol (46%), and Tafil (25%), drugs highly associated with nonmedicinal use among United States teenagers and young adults. These data reinforce a documented need for more transnational cooperative efforts between the United States and Mexico.
OBJECTIVE: To clinically evaluate the protective effect of procaine blocking on nerves. METHODS: Electrophysiological examination before and after procaine blocking was conducted on 32 nerves during operation, 18 of which were donor nerves and 14 were injured ones. RESULTS: The latency of somatosensory evoked potentials (SEPs) was lengthened (15.30%) and the amplitude was lowered (18.47) after procaine blocking. Compared with the values before procaine blocking, the differences were significant (P < 0.01 and P < 0.05, respectively). SEP waves disappeared after procaine blocking in some cases (28.13%). CONCLUSION: Latency of SEP is lengthened and amplitude is lowered after procaine blocking. In some cases, SEPs even disappear.
It has been found that plateau hypoxia could induce apoptosis in rats' brain, but the mechanism was not clear. In order to study it further, we utilized acute intermittent hypoxia model to investigate reduced gliutathione (GSH), oxidized gliutathione(GSSG), super-oxide dismutase (SOD) and programmed cell death (PCD) or apoptosis (AP) in rats' brain. The results showed that with the increase of hypoxic exposure duration, apoptotic cells increased, the ratio of GSH/GSSG and the activity of SOD dropped. Regression analysis showed that there was a negative power relationship between the number of apoptotic cells and the ratio of GSH/GSSG or between the number of apoptotic cells and the activity of SOD in a limited range. It was concluded that there would be an intrinsic relationship between apoptosis and free radical scavenging ability in the organ.
Grafting hydrogels onto silicone rubber membranes were prepared by radiation technique for medical application. This material is characterized by high purity, hydrophilia, formation of stable hydrogel after water absorption, good biocompatibility, etc. Clinical application was initiated on the basis of animal experiments. The material was used in 47 cases of joint and tendon injuries, in 9 cases of rheumatoid arthritis, and in 4 other cases; totaling 60 cases. All patients were followed up for three and a half years after surgical operation. A general effectiveness of above 86% was noted.
Considering the Fåhraeus effect and the blood volume regulation role of the microcirculation, we used a new method for calculating the blood volume change in microcirculation, macrocirculation as well as the whole circulation (delta Vmic, delta Vmac, delta Vb), to compare fluid therapy effects of hypertonic saline dextran solution (HSD) and lactic Ringer's solution at the early stage after burn-blast combined injury (BBI). The measurement of plasma viscosity was used in this calculation. The results showed that, with calculation of the blood volume change in microcirculation and macrocirculation, this method could more exactly and distinctly display the change and distribution of blood volume during the therapy. It confirms that HSD treatment can increase blood pressure and attenuate tissue edema, by significantly increasing total blood volume, recouping delta Vmac. The study suggests that a desirable and practical clinical method for blood volume change can be developed based on the present study.
This study investigated the incidence and patterns of substance use in a school-age population, as well as predictive risk factors that may play an important role in understanding its initiation. Low socioeconomic status Mexican American fourth-, fifth-, and sixth-grade students were surveyed for two consecutive years in order to obtain information on their substance use and its relationship to specific demographic, environmental, and psychological risk factors. Results capture patterns of substance use among this population over the two years, as well as the relationship between reported risk factors in year one and the use of minor and major substances in year two.
OBJECTIVE: To investigate whether type 1 helper (Th1) or Th2 cytokines are found in the joints of patients with Lyme arthritis, and whether the cytokine pattern can be modulated by cytokines or anticytokines. METHODS: The cytokine pattern in the joints of 10 patients with Lyme arthritis was investigated. Expression of interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), interleukin-4 (IL-4), and IL-10 was measured by enzyme-linked immunosorbent assay (ELISA), after stimulation of synovial fluid mononuclear cells (SFMC) with Borrelia burgdorferi (Bb) in the supernatant. Expression of cytokine messenger RNA and protein in synovial membrane (SM) and nonstimulated SFMC was studied using semiquantitative reverse transcriptase-polymerase chain reaction and immunohistologic techniques. The effects of recombinant cytokines or neutralizing anticytokine antibodies on cytokine production in Bb-stimulated SFMC were investigated by ELISA. RESULTS: SFMC produced high amounts of IFN gamma and TNF alpha, but little or no IL-4, upon stimulation with Bb antigen, indicating a Th1-type cytokine pattern. In SM, IFN gamma was detectable in all patients, while the other cytokines were less frequently found. Serial sections of SM revealed that all cytokines were located in the same area. The Th1 response, especially the production of TNF alpha, could be down-regulated in vitro by both endogenous and exogenous IL-10, but not by IL-4 or anti-IL-12. CONCLUSION: A Th1-type cytokine pattern was found in the joints of patients with Lyme arthritis. This Th1 response could be down-regulated by IL-10, suggesting insufficient IL-10 production in vivo.
OBJECTIVE: To investigate whether a predominant type 1 T helper (Th1) or Th2 cytokine pattern is present in the joints of patients with reactive arthritis (ReA), and whether the cytokine pattern can be modulated by cytokines or anticytokines. METHODS: Eleven patients with ReA following infection with either Chlamydia trachomatis, Yersinia enterocolitica, or Salmonella enteritidis were investigated for the presence of Th1/Th2 cytokines in the joints. Release of the bacteria-specific cytokines interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), interleukin-10 (IL-10), and IL-4 was measured in synovial fluid mononuclear cells (SFMC) using enzyme-linked immunosorbent assay and polymerase chain reaction. In the synovial membrane, secretion of IFN gamma and IL-4 was determined by immunohistologic analysis. Cytokine regulation was studied by adding cytokines and anticytokines to the cultures. RESULTS: Upon stimulation with specific bacteria, SFMC secreted low amounts of IFN gamma and TNF alpha, but high amounts of IL-10. IL-10 was responsible for the suppression of IFN gamma and TNF alpha, as judged by the effect of adding either anti-IL-10 antibodies or exogenous IL-10 to these cultures. The addition of neutralizing anti-IL-12 to the cultures completely abolished the effects of anti-IL-10, suggesting that inhibition of the Th1-like cytokines by IL-10 is mediated through suppression of IL-12 synthesis. Exogenous IL-12 clearly enhanced IFN gamma and TNF alpha secretion. In the synovial membrane, a higher number of cells were positive for the Th2 cytokine IL-4, compared with the amount of IFN gamma-secreting cells. CONCLUSION: These data indicate that a Th2 cytokine pattern predominates in the joints of patients with ReA. Since Th1 cytokines are necessary for the elimination of ReA-associated bacteria, Th2 cytokines might contribute to bacterial persistence in the joint. Therefore, the IL-10/IL-12 balance appears to be crucial for regulation of the cytokine pattern in the joints of patients with ReA.
In a previous paper (Yin et al., Electrophoresis 1996, 17, 1143-1150), an automated method for matrix determination in four-dye fluorescence-based DNA sequencing was presented. As a continuation of that work, we have developed an alternative method to estimate the matrix from raw sequence data. The method uses an iterative clustering technique to associate each 4 x 1 data vector with one column of the desired filter matrix, using Kullback's I-divergence as a distance measure. The method requires less preprocessing of the data and less computation than the approach described by Yin et al. (Electrophoresis 1996, 17, 1143-1150). An example demonstrating applicability of the proposed method to Applied Biosystems sequencer data is given.
In orthogonal and pair design tests, mink, guinea-pigs and rabbits were inoculated with inactivated mink enteritis virus (MEV) vaccine prepared with mineral oil or Al(OH)3 gel adjuvant. The animals were examined for serum haemagglutination-inhibition (HI) antibody during 6-55 days postvaccination (p.v.) and serum-neutralizing (SN) antibody for 11-31 days p.v. Differences between mineral oil and Al(OH)3 gel adjuvant vaccines in the induction of HI and SN antibodies during 6-55 days p.v. were not significant. There was significant positive rank correlation between HI antibody level and SN antibody index from 11 to 31 days p.v. in serum of mink inoculated with the mineral oil or Al(OH)3 gel adjuvant vaccine (P < 0.05). The results of experimental challenge tests with vaccines in 29 mink showed a positive correlation between HI antibody titres, SNI and immune protective rates. Levels of HI antibodies in guinea-pigs, rabbits or mink during 11-40 days p.v. were reliable indices for monitoring the humoral immune responses and immune protective rates. The criteria for virus vaccine potency and vaccine immune efficiency is an HA titre of 64 for the cell-cultured MEV and an HI antibody titre of 32 for guinea-pigs, rabbits or mink during 11-40 days p.v. The vaccine stimulates a protective response which lasts for a period of 12 months. The vaccine is stable for a period of 9 months at 4 degrees C. Economic, simple and scientific means have been developed to monitor the quality of MEV vaccines, of which more than 70,000 doses of the mineral oil vaccine and more than 18,000,000 doses of the Al(OH)3 gel vaccine have been used for the last 5 years.
The Drosophila tinman homeobox gene has a major role in early mesoderm patterning and determines the formation of visceral mesoderm, heart progenitors, specific somatic muscle precursors and glia-like mesodermal cells. These functions of tinman are reflected in its dynamic pattern of expression, which is characterized by initial widespread expression in the trunk mesoderm, then refinement to a broad dorsal mesodermal domain, and finally restricted expression in heart progenitors. Here we show that each of these phases of expression is driven by a discrete enhancer element, the first being active in the early mesoderm, the second in the dorsal mesoderm and the third in cardioblasts. We provide evidence that the early-active enhancer element is a direct target of twist, a gene encoding a basic helix-loop-helix (bHLH) protein, which is necessary for tinman activation. This 180 bp enhancer includes three E-box sequences which bind Twist protein in vitro and are essential for enhancer activity in vivo. Ectodermal misexpression of twist causes ectopic activation of this enhancer in ectodermal cells, indicating that twist is the only mesoderm-specific activator of early tinman expression. We further show that the 180 bp enhancer also includes negatively acting sequences. Binding of Even-skipped to these sequences appears to reduce twist-dependent activation in a periodic fashion, thus producing a striped tinman pattern in the early mesoderm. In addition, these sequences prevent activation of tinman by twist in a defined portion of the head mesoderm that gives rise to hemocytes. We find that this repression requires the function of buttonhead, a head-patterning gene, and that buttonhead is necessary for normal activation of the hematopoietic differentiation gene serpent in the same area. Together, our results show that tinman is controlled by an array of discrete enhancer elements that are activated successively by differential genetic inputs, as well as by closely linked activator and repressor binding sites within an early-acting enhancer, which restrict twist activity to specific areas within the twist expression domain.
Few comparative studies exist examining the relationship between substance abuse and aggressive behavior under different social conditions. We studied the relationship between aggressive crime and substance abuse among Mexican-American, black and white male arrestees in Dallas, Houston, and San Antonio, Texas using existing 1992 Drug Use Forecasting (DUF) data. The aim of the analysis was to predict the outcome of aggressive crime from drug and alcohol-related and ethnic group variables within the total male sample (n = 2,364). Results indicated that ethnicity was significantly related to aggressive crime. Mexican-American arrestees were more likely to be arrested for aggressive crimes than either blacks or whites. Drug and alcohol use effects were found across all ethnic groups. In general, the subgroup which drank frequently and tested positive for drug use was less likely to be charged with aggressive crimes than the other subgroups. The psychopharmacological influence of alcohol as a disinhibitor and drugs as a inhibitor provides one explantation of the results. Specific ethnic subcultural and ecological influences also affect the outcome. Our study strongly indicates the heterogeneous character of the drug using population in relation to aggression. The variability between subculturally defined subgroups requires detained ethnographic field studies in the future to describe the contexts of substance use and aggressive behavior.
Laser transnasal dacryocystorhinostomy under head mirror is a new approach for surgical treatment of chronic lacrimal obstruction. This technique has several advantages, such as less damage, less operative complications and so on. This paper presented the results of 37 cases who had undergone transnasal dacryocystorhinostomy for chronic dacryocystitis under head mirror. The postoperative follow-up time was 3-24 months. The effective rate was 95.6%. The operative technique was also discussed in this paper.
This paper deals with the morphological identification, TLC analysis and survey of commercial crude drug of Herba Cistanchis (Genus Cistinche). This results provide authentic methods for the identification of Herba Cistanchis.
Normal and neoplastic leukocytes interact with the central cell-binding and carboxyl-terminal regions of fibronectin (FN) primarily via the alpha(4) beta(1) and alpha(5) beta(1) integrins. By using a unique centrifugation-based cell adhesion assay and affinity chromatography of the cell surface-labeled integrins, we show in this study that the constitutive alpha(5) beta(1)-dependent attachment of three leukemic cell lines, BV-173, K562, and Nalm-6, to FN or to a 110-kDa central cell-binding fragment of FN was totally inhibited at 37 degrees C by preincubation of the substrate with either antibodies to the arginine-glycine-aspartic acid-containing region (3Fn-9 module) or to the synergistic region (3Fn-9 module) of FN. Similar results were obtained when assays were carried out at 4 degrees C, suggesting that energy-dependent events were not involved. On the other hand, only the antibody against the 3Fn-10 module was able to detach most firmly adherent cells. Constitutive cell attachment to the 110-kDa fragment was cation dependent, with the order of efficacy of the cation being Mn2+ > Mg2+ > Ca2+, and Ca2+ was only effective for BV-173 cells. Antibodies against the alpha(5) beta(1) integrin or the alpha(5) subunit completely impaired cell attachment of all cell lines, whereas several blocking anti-beta(1) subunit antibodies, including 4B4, P4C10, and AIIB2, differentially perturbed cell adhesion of BV-173, depending on which cation was present. These anti-beta(1) blocking antibodies, whose epitopes map to a region distant from the one expected to contain the beta(1) putative cation binding sites, seemed to lock the higher activation state of this integrin attained in the presence of Mg2+ and to preserve it during the subsequent adhesion events irrespectively of the presence of the low avidity state-inducing Ca2+ ion. Because the higher binding avidity displayed by BV-173 could not be explained by a higher degree of preclustering of alpha(5) beta(1) integrin in this cell line compared to K562, these findings suggest that cations might act as allosteric activators of integrin function. Whether this novel cation-dependent parameter of alpha(5) beta(1) integrin-FN interaction might contribute to the growth control and/or tissue dissemination of leukemic cells remains to be determined.
The four dye fluorescence detection strategy is a widely used approach to automated DNA sequence analysis. An important aspect of data processing in this approach is the multicomponent analysis to deduce the concentrations of four fluorophores from fluorescence emission intensities at four different wavelengths. This requires knowledge of the correct transformation matrix M. The matrix M is a function both of the fluorophores employed and the fluorescence detection system. M is typically determined either by a calibration process with individual dyes, or by choosing four well-separated individual peaks corresponding to the four different dyes. Both are time-consuming and complicated procedures for routine use. An automatic scheme for finding M directly from raw sequence data is presented here. This facilitates data analysis and the underlying algorithm may also find utility in other multispectral applications.