Biomedical subjects

Z Qian

Publications and source records attributed to Z Qian.

At least 91 records · Page 5Linked to original sources

PubMed1995

Outcomes of open cholecystectomy in the elderly: a longitudinal analysis of 21,000 cases in the prelaparoscopic era.

OBJECTIVE: We sought to obtain unbiased estimates of open cholecystectomy outcomes in a population-based cohort of elderly patients during the immediate prelaparoscopic era. METHODS: Medicare claims data were used to identify 21,131 patients aged 65 years or more who underwent open cholecystectomy in Pennsylvania between 1986 and 1989 and to develop longitudinal histories of hospitalizations and physician services utilization for these patients. Study patients were divided into three groups: simple cholecystectomy, cholecystectomy with intraoperative cholangiography (IOC) alone, and cholecystectomy with common bile duct exploration (CBDE). Outcomes examined included 30- and 90-day postoperative mortality rates and postoperative complications. RESULTS: Postoperative mortality rates in all patients was 2.1% at 30 days and 3.6% at 90 days. Patients in the CBDE group had a significantly higher mortality rate than those in the simple cholecystectomy or IOC groups; adjusted for differences in case mix, the mortality rate in the CBDE group was 47% higher at 30 days and 29% higher at 90 days. Rates of retained or recurrent common duct stones, bile duct stricture, and recurrent biliary tract surgery by 42 to 60 months after cholecystectomy were 2.8%, 0.4%, and 1.0%, respectively. CBDE was a strong risk factor for these complications. In contrast, the IOC group had a significantly lower risk of having clinically manifest retained or recurrent common duct stones develop by 42 months after operation. CONCLUSIONS: This study provides an unbiased assessment of open cholecystectomy outcomes necessary for future comparisons of open and laparoscopic cholecystectomy in elderly patients. Estimates of the excess mortality rates associated with CBDE provide a benchmark for assessing the outcomes of alternative strategies for managing common duct stones during laparoscopic cholecystectomy. Findings regarding the rates of retained or recurrent common bile duct stones in patients undergoing simple cholecystectomy and IOC challenge widespread beliefs about the limited clinical importance of unsuspected common duct stones, at least in the elderly population, and are relevant to the debate about routine IOC.

Aged↗

PubMed1995

Transcatheter occlusion of patent ductus arteriosus using a newly developed self-expanding device. Evaluation in a canine model.

RATIONALE AND OBJECTIVES: A new occlusion device designed for use in a patent ductus arteriosus was tested in an animal model. METHODS: The device consists of a self-expanding conical-shaped stainless steel mesh, with hooks encircling the expanding end acting to secure the device within the ductus. A screw thread at the apex allows attachment to a stylet, and a 6 F delivery system is used. Placement of the device was attempted in 20 canines that previously had a vascular graft surgically inserted between the descending thoracic aorta and main pulmonary artery, creating the patent ductus model. Angiographic follow-up at regular intervals was performed over a 3-month period. RESULTS: Early cases resulted in device misplacement and migration because of inaccurate assessment of ductus position and size. In 15 canines the device was placed within the ductus and regularly assessed over the 3-month placement period. Ductus occlusion occurred within 1 week in 12 of 13 dogs (92%) when device placement was considered ideal. In two dogs where significant protrusion of the device from the ductus was evident (either into the aorta or main pulmonary artery) ductus closure was delayed but present by 3 months, resulting in a 93% overall closure rate at this time. In one dog, the ductus remained partially opened. CONCLUSIONS: This self-expanding patent ductus arteriosus occlusion device is promising. The 6 F delivery system is advantageous over other devices currently available, making it more suited for use in the pediatric population. Accurate assessment of the ductus is imperative, however, to enable correct device sizing. The screw thread system allows the device to be repositioned if desired prior to deployment.

Animals↗

PubMed1995

Transactivation activity of Meq, a Marek's disease herpesvirus bZIP protein persistently expressed in latently infected transformed T cells.

Marek's disease virus (MDV) is an avian herpesvirus that induces a variety of diseases, including T-cell lymphomas, in chickens. In latently infected, transformed lymphoid cells, very few viral transcripts or proteins are detected. We previously described a gene, meq (MDV EcoQ), which is persistently expressed in MDV-transformed tumor samples and cell lines. meq codes for a 339-amino-acid protein with a basic-leucine zipper domain near its N terminus and a proline-rich domain near its C terminus. The basic-leucine zipper domain shows homology with Jun/Fos family proteins, whereas the proline-rich domain resembles that of the WT-1 tumor suppressor protein. These structural features raise the possibility that Meq functions as a transcription factor in regulating viral latency or oncogenesis. In this report, we show that the proline-rich domain is a potent transcription activator when fused to the yeast (Saccharomyces cerevisiae) Gal4(1-147) DNA-binding domain. The transactivation activity maps to the C-terminal 130 amino acids, with the last 33 amino acids essential. In the absence of these 33 amino acids, a two-and-one-half proline-rich repeat structure was found to exhibit repression activity. We further show that Meq is able to dimerize not only with itself but also with c-Jun. Meq/c-Jun heterodimers bind to an AP1-like sequence in the meq promoter region with an affinity much greater than that of Meq/Meq or c-Jun/c-Jun homodimers. Cotransfection chloramphenicol acetyltransferase assays suggest that the Meq/c-Jun heterodimers can up-regulate Meq expression in both chicken embryo fibroblasts and F9 cells. Our data provide the first biochemical evidence that Meq is a transcriptional factor and identify c-Jun as one of Meq's interacting partners.

Amino Acid Sequence↗

PubMed1995

Gender influences sphincter of Oddi response to cholecystokinin in the prairie dog.

Although gallstones and disorders of biliary tract motility are both more common in women than men, sphincter of Oddi motility has not previously been compared between the sexes. In this study, cholescintigraphy (under ketamine and diazepam anesthesia) was used to determine gallbladder emptying rate and ejection fraction in response to cholecystokinin (CCK) in eight male and six female prairie dogs fed a nonlithogenic diet. Ten days later, under alpha-chloralose anesthesia, sphincter of Oddi phasic wave activity was monitored for 10-min intervals before (control), during 20 min of CCK infusion, and for 20 min after infusion. Gallbladder emptying rate and ejection fraction and baseline sphincter of Oddi frequency, amplitude, and motility index (= frequency x amplitude) did not differ significantly between the sexes. Sphincter of Oddi phasic wave frequency was increased during CCK infusion in both males and females, but the change in amplitude was significantly greater in females, than males. We conclude that the increased incidence of biliary tract disease in women may be due to altered sphincter of Oddi hormonal response.

Animals↗

PubMed1995

[A preliminary report on diagnostic complementarity of gut-associated and egg-associated antigenemia in schistosomiasis japonica].

With Hyroxylapatite purified preparations and BACH (biotin aminocapryl hydrazide) biotinylated McAbs, 274-2H10 and 273-2H1, recognizing different egg-associated epitopes, biotin-avidin (BA) involved alkaline phosphatase (AP) ELISA with detecting sensitivities reaching nanogram levels (10(-9), were set up. The detectable limit for crude preparations of Schistosoma japonicum SEAJ-TCA in 2H10-ELISA achieved 1. 0.3. 2 ng/ml, in which only S. japonicum specific egg antigens were efficiently detected, whereas with 2H1-ELISA, which could detect SEA-TCA of both S. japonicum and S. mansoni species, an end point of detecting 3.2 ng/ml was obtained. Repeated tests with human serum groups revealed very significant differences of extinction OD readings between patients and normal individuals. For detection combinations, a previously established anti-CAA homologous AP-ELISA system was parallelly used for gut-associated antigenemia determinations. Taking the mean extinction OD reading of a parallel normal serum group plus 3 SD as corresponding cut off values, 3 patient groups (n = 82, 52, 39) from different areas of transmission intensity were subjected to accumulating determinations for egg- and gut-associated antigenemia. Improved detectabilities to variable extent were achieved in either of the 2 or 3 combinations. The study thus demonstrated that the diagnostic efficiency for human schistosomiasis could be improved by multi-epitope detections for more than one target molecule using corresponding McAbs, especially in areas where the transmission intensity of the disease is comparatively lower.

Animals↗

PubMed1995

[The direct repair of the defect and grafting with single segment reduction fixation system in the treatment of lumbar spondylolysis and spondylolisthesis].

We designed lumbar spondylolysis and spondylolisthesis single segment reduction fixation system according to neural arch measured in the 46 dried specimen. The biomechanical tests showed that its strength is 1.6 times that of Hefti's technique, 2.7 times that of Salib's technique. It used contacted point lamina by lamina hook as fulcrum, through lever and pedicle screw to pull back olisthetic vertebrae. 18 patients were treated with this method. The displacemen rate was 26.67% before operation and 3.38% after operation. The height of disc was 14.94 mm before operation and 17.08 mm after operation. 15 patients were followed up for 12 months. By Henderson standard, excellent result was moted in 13 patients, good in 1 and fair in 1. We conclude that LSRF has good reduction and rigid fixation and it is a new technique for lumbar spondylolysis and spondylolisthesis.

Adult↗

PubMed1994

Integration of multiple chicken retroviruses into multiple chicken herpesviruses: herpesviral gD as a common target of integration.

Integration of two different avian retroviruses, reticuloendotheliosis virus (REV) and avian leukosis virus (ALV), into the genome of two different avian herpesviruses, the herpesvirus of turkeys (HVT) and Marek's disease virus (MDV), was investigated. Integration events occurred by the fourth and sixth in vitro passage of cells coinfected with REV/HVT and ALV/MDV, respectively. In order to further characterize the integration events, integrated proviruses and surrounding herpesviral genetic material were cloned and analyzed. In the REV/HVT coinfection experiment, one of the three unique integrated proviruses was found to have integrated into the HVT gD gene, resulting in disruption of the coding region of this gene. The two additional unique integrations were localized to the UL and IRL border regions of HVT, two previously described common sites of REV integration into MDV. Interestingly, one of the integrated proviruses in the HVT genome appeared to be full length, was infectious when transfected into CEF cells, and therefore could potentially function to produce infectious REV from an HVT infectious platform. In the ALV/MDV coinfection experiment, one of two unique integrated proviruses was found to have integrated into the gD gene, resulting in disruption of the coding region of this gene. The second unique integration site was in the polyadenylation site of the SORF2 gene at the boundary of the IRS and US, once again a common site of REV integration into MDV. These results demonstrate that the U/IR-TR border regions of herpesviruses are common sites of retroviral integration. In addition gD, in the US region of the herpesvirus, is a common site of retroviral integration in multiple herpesvirus, indicating a possible selective advantage for disruption of this gene in the in vitro growth of a herpesvirus. Finally, this is the first instance of a full-length provirus found integrated into a herpesvirus genome, indicating that a retrovirus could alter its route of infection by being carried in a herpesvirus genome.

Amino Acid Sequence↗

PubMed1994

GRSF-1: a poly(A)+ mRNA binding protein which interacts with a conserved G-rich element.

Computer predictions identified similarities to a 14-base G-rich element in numerous mRNAs at a variety of locations. A Northwestern screening strategy was used to obtain a cDNA clone from a HeLa cell library using the G-rich RNA element as a probe. A cellular protein (called GRSF-1), which was encoded by this cDNA, binds RNAs containing the G-rich element. GRSF-1 was distinct from DSEF-1, a nuclear protein we have previously identified that interacts with the G-rich element, based on differences in molecular weight and partial peptide maps, as well as the lack of cross-reactivity with GRSF-1 specific monoclonal antibodies. Using indirect immunofluorescence microscopy, we localized GRSF-1 to the cytoplasm. In vivo UV cross-linking further demonstrated that GRSF-1 was bound to poly(A)+ mRNA in living human cells. Western blot analysis revealed four cytoplasmic proteins which expressed GRSF-1 specific epitopes. GRSF-1 contains three potential RNA recognition motifs and two auxiliary domains. Curiously, the domain organization of GRSF-1 is similar to the RNA binding proteins PUB1, ELAV, HuD, Hel-N1, mcs94-1 and RBP9.

Amino Acid Sequence↗

PubMed1994

Estrogen inhibits sphincter of Oddi motility.

Gallstones and sphincter of Oddi dysfunction are both more common in women than men, suggesting that endogenous hormones may play an important role in these conditions. Female sex hormones are known to affect cholesterol metabolism and gallbladder motility. However, the effect of these hormones on the sphincter of Oddi has not previously been studied. We therefore tested the hypothesis that exogenous estrogen administration would inhibit sphincter of Oddi motility. Twenty-three male prairie dogs fed a nonlithogenic diet were studied. Under alpha-chloralose anesthesia, a side hole pressure-monitored perfusion catheter was positioned in the sphincter of Oddi and perfused with degassed water at 0.15 ml/min. Femoral arterial and venous catheters were placed. Sphincter of Oddi phasic wave frequency (F), amplitude (A), and motility index (MI = F x A), as well as arterial blood pressure (BP), were monitored for 10-min intervals before (control), during 20-min intravenous infusions of 0.1, 1, or 10 micrograms/kg beta-estradiol, and for 20 min after estradiol infusion. No response was observed at the 0.1- or 1-micrograms doses. Sphincter of Oddi motility was significantly (P < 0.05) reduced during estrogen infusion at the higher dose of 10 micrograms, primarily due to decreased phasic wave frequency. Sphincter motility remained depressed for at least 20 min following estrogen infusion. We conclude that estrogen effects on the sphincter of Oddi may contribute to the higher incidence of gallstones and sphincter dysfunction seen in premenopausal women.

Animals↗

PubMed1994

[Analysis of the target epitopes recognized by two monoclonal antibodies directed to egg-associated fractions of Schistosoma japonicum].

Two IgM isotype monoclonal antibodies (McAb), 2H10 and 2H1, recognizing repetitive epitopes on Schistosoma egg-associated molecules were characterized and their specificities were identified in a two-site sandwich ELISA system. In consistent with the differences in immunological behaviour and specificity demonstrated with immunoelectrophoresis (IEP) and immunofluorescent antibody (IFA) techniques, absolutely negative reactions found in the heterologous detecting system with alternated capture and detecting McAbs of the two revealed a complete incompatibility giving evidences that epitopes on different molecules were recognized. Immunological liability of the target antigen SEA or SEA-TCA to the two McAbs were demonstrated on sodium periodate and trifluoroacetic acid treatment indicating the biochemical nature of these epitopes were glycosyolated molecules with apparently higher resistance to the oxidizing agent showing in 2H10 recognizing epitopes. By means of an ion-gradient Mono-Q FPLC system (Pharmacia), 2H10-reactive epitopes of SEA, being tested not so efficiently adsorbed by ConA-sepharose affinity column, was found successfully concentrated in the profile eluted with pH 8.0 PBS at 0.2-0.4 NaCl ionic strength. Repeated trials on SDS-PAGE and Western blotting analysis with the reactive fractions further showed a heterogeneity of molecular weight range as well as the non-transferable property of the CHO-reactive groups.

Animals↗

PubMed1994

[Treatment of 842 cases with cystic echinococcosis of chest].

842 cases of thoracic echinococcosis were surgically treated by endocystectomy (79%), pneumonectomy (12%), drainage and other operations (9%). Among a total of 1,010 operations, the mortality was 0.6% (5/807). Of 637 cases received 798 endocystectomies, the recurrence rate was 4.2% (27/638). Up to 1979, the first series of 323 cases were followed-up for 3-20 years, no single case died of thoracic echnococcosis. Among the 32 non-operation cases, the mortality was 22.2% (6/27) and 9 cases were spontaneously cured. 22 cases were given praziquantel at two dosages, Group A received 120-150 mg/kg and Group B received 210 mg/kg in divided doses for 5-6 days. The death rate of protoscolices inside the operatively removed cystic fluid from the above two groups was 43.1 +/- 9.6% and 64.2 +/- 3.5%, respectively, while in the untreated Group C 9.2 +/- 2% (P < 0.01). With total dosage of praziquantel 300 mg/kg in divided doses for 7 days, the concentration of praziquantel in patient's blood and cystic fluid was 0.49 +/- 0.075 microgram/ml and 0.006 microgram/ml, respectively.

Adolescent↗

PubMed1994

Functional and structural relation between central chemoreception of respiration and the nucleus retrofacialis in rats.

Iontophoresis of hydrogen ions (H+) to respiration related units (RRUs) in the nucleus retrofacialis (NRF) region was used to investigate the role of RRUs in central chemoreception of respiration. The results were as follows: 1) of the 13 inspiration related units (InRUs) recorded, 7 were excitatory and 1 was inhibitory; 2) of the 29 expiration related units (ExRUs), 12 were inhibitory and 1 was excitatory; and 3) of the 7 phase-spanning respiration related units (PSUs), 4 were excitatory and 2 were inhibitory. None of the remainder were affected. Histochemical study using the horseradish peroxidase (HRP) technique revealed a neural structural relation between the ventral surface of the medulla and neurons in the NRF region. It was suggested that the RRUs in the NRF region might contribute to the central chemoreception which regulates respiration.

Animals↗

PubMed1993

Cloning of a cDNA encoding an RNA binding protein by screening expression libraries using a northwestern strategy.

Successful cloning with cDNA expression libraries involves interaction of ligand molecules (probes) with expressed fusion proteins of interest. So far those ligands leading to successful results fall into three classes: (i) antibodies, (ii) protein ligands that interact with the protein of interest, and (iii) DNA sequences recognized by transcription factors. We have previously identified a 50-kDa protein (called DSEF-1) which interacts with a functionally important 14-base G-rich RNA sequence located downstream of the simian virus 40 late polyadenylation signal. By using small RNAs containing the DSEF-1 binding site as probes, a cDNA clone was isolated whose gene product interacted in a sequence-specific fashion with the DSEF-1 binding site. This RNA binding protein contains three potential RNA recognition motifs. We present here a procedure to obtain cDNA clones of RNA binding proteins using recognition site probes.

Bacteriophage lambda↗

PubMed1993

Tissue-plasminogen activator is induced as an immediate-early gene during seizure, kindling and long-term potentiation.

The requirement of protein and messenger RNA synthesis for long-term memory suggests that neural activity induced by learning initiates a cascade of gene expression. Here we use differential screening to identify five immediate-early genes induced by neuronal activity. One of these is tissue-plasminogen activator (tPA), an extracellular serine protease, which is induced with different spatial patterns in the brain by three activity-dependent events: (1) convulsive seizure increases expression of tPA in the whole brain; (2) stimulation of the perforant path produces an epileptiform after-discharge that ultimately leads to kindling increases the levels of tPA throughout the hippocampus bilaterally; and (3) brief high-frequency stimulation of the perforant path that produces long-term potentiation (LTP) causes an NMDA (N-methyl-D-aspartate) receptor-mediated increase in the levels of tPA mRNA which is restricted to the granule cells of the ipsilateral dentate gyrus. As release of tPA is correlated with morphological differentiation, the increased expression of tPA may play a role in the structural changes that accompany activity-dependent plasticity.

3T3 Cells↗

PubMed1993

Reliability and usefulness of a new immunochemical assay for Alzheimer's disease.

OBJECTIVE: To assess the reliability and usefulness of a new sandwich enzyme-linked immunoassay (ALZ-EIA) that detects Alzheimer's disease-associated proteins in the diagnosis of Alzheimer's disease. DESIGN: The reliability of the assay was assessed between two laboratories. Sensitivity and specificity of a diagnostic algorithm based on the results of the ALZ-EIA were determined using the Consortium to Establish a Registry for Alzheimer's Disease neuropathological diagnoses as the "gold standard." SETTING: Autopsy cases were obtained from a teaching hospital with a specialized Alzheimer Disease Diagnostic and Treatment Center. CASES: Brain tissue was selected from 24 cases with dementia and 10 normal controls. MAIN OUTCOME MEASURES: Optical density measurements from the ALZ-EIA in the hippocampus and three neocortical regions. RESULTS: A 95% concordance in ALZ-EIA activity was found between the two laboratories, and an 85% concordance was found between ALZ-EIA and the Consortium to Establish a Registry for Alzheimer's Disease diagnoses. Perfect agreement was obtained for "typical" Alzheimer's disease cases (those with plaques and tangles), while discrepancies occurred for "atypical" cases (those with predominantly plaques or tangles). CONCLUSIONS: The ALZ-EIA provides a highly reliable method of assessing neurofibrillary degeneration. Its clinical usefulness as a diagnostic test would be enhanced by the availability of a complementary assay for beta-amyloid.

Aged↗

PubMed1993

Evaluation of a new vascular occlusion device.

RATIONALE AND OBJECTIVES: A new vascular occlusion device was tested in canine femoral and iliac arteries and in an animal model of a patent ductus arteriosus (PDA). METHODS: Four variations of the vascular plug were placed into 18 iliac or femoral arteries of 17 mongrel dogs. Follow-up angiography was performed 1 hour and, if necessary, 2 hours after placement in all animals, 14 of which were then killed. Three dogs were followed angiographically for 2 weeks to 3 months. The "butterfly" plug was then tested in a canine model of a PDA. RESULTS: All plugs contained thrombi, and 12 of the 18 devices caused complete or nearly complete vascular occlusion within 2 hours. In one dog, one vascular plug had eroded through the vessel wall at 3 months without clinical sequelae. Successful PDA occlusion was achieved in 1 or 2 days in 6 of 8 dogs. Three misplacements occurred, one of which resulted in death. DISCUSSION: The balloon-expandable vascular plug appears to be a promising device for occlusion of blood vessels. Migration has not been observed once the device is placed, thus, sizing of the device appears less critical than with coils. However, modification of the delivery system and considerably more experience with the device are necessary to reduce the risk of misplacement.

Animals↗

PubMed1993

Effects of iontophoretically applied morphine on respiration related units in the medial part of the nucleus retrofacialis region in rats.

The effects of morphine on 108 spontaneously discharging units in the medial part of the nucleus retrofacialis (mNRF) were studied in 13 SD rats anesthetized with urethane and allowed to breathe spontaneously. A 5-barrelled microelectrode was inserted into the mNRF region to record discharges of respiration related units (RRUs) and nonrespiration related units (NRRUs), and then morphine was administered by iontophoresis. Among the 27 inspiration related units (InRUs) recorded, morphine exerted an inhibitory effect on 8 units and an excitatory effect on 6 units; while among the 36 expiration related units (ExRUs), the excitatory effect was much more obvious than the inhibitory effect (12 vs 2). This difference was statistically significant. The results revealed a difference between the effects of morphine on InRUs and ExRUs in the mNRF region. The excitatory effect of morphine on ExRUs in the mNRF region might play a role in the mechanism by which morphine depresses respiration.

Animals↗

PubMed1993

Role of respiration related units in the nucleus retrofacialis region in rats.

Experiments were carried out on 10 urethane anesthetized, spontaneously breathing rats. The distribution of respiration related units (RRUs) in the nucleus retrofacialis (NRF) region was explored systematically with an extracellular recording technique and their discharging patterns were analyzed through a microcomputer. A total of 212 spontaneously discharging units were recorded in the NRF region. Among them 120 were RRUs and the remainder were non-respiration related units (NRRUs). Among the RRUs, 28 were determined to be inspiration related units (InRUs); 81 were expiration related units (ExRUs) and 11 were phase-spanning respiration related units (PSUs) according to their temporal relation to phrenic activity. These RRUs were further classified into augmenting, decrementing and constant types based on their discharge patterns. The results indicated that RRUs in the NRF region were relatively abundant as compared to NRRUs, and they were more concentrated in the medial part of the NRF region (mNRF). Among them, ExRUs were predominant.

Animals↗