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Biomedical subjects

Z Y You

Publications and source records attributed to Z Y You.

9 recordsLinked to original sources
PubMed2005

Relationship between bridging with ventricular assist device on rejection after heart transplantation.

BACKGROUND: Ventricular assist devices (VADs) are commonly used to bridge patients to heart transplantation. Recipients of VADs may develop anti-human histocompatibility leukocyte antigen antibodies, as reflected by elevated panel-reactive antibodies (PRA). The purpose of this study was to evaluate the relationship between bridging with VAD before heart transplantation and development of cellular rejection, humoral rejection, and allograft vasculopathy after transplantation. METHODS: Data on all patients who underwent cardiac transplantation between July 1994 and February 2001 at Rush Presbyterian St Luke's Medical Center were retrospectively reviewed. Data collected included sex, age, etiology of cardiomyopathy, percentage panel reactive antibodies (by cytotoxic method), type and duration of mechanical circulatory support, transfusion history, rejection history (both cellular and humoral) after cardiac transplantation, and development of allograft vasculopathy. Cellular rejection was treated when International Society of Heart and Lung and Transplantation Grade 2 or greater in the first 12 months after transplant and Grade 3 or greater after 12 months and treated with intensification of immunosuppression. Humoral rejection was defined clinically as allograft dysfunction by echocardiography without evidence of cellular rejection on endomyocardial biopsy or allograft vasculopathy. Allograft vasculopathy was defined by presence of any degree of luminal narrowing or pruning of distal vessels by coronary arteriography. Statistical analyses were performed by chi-square test, Fisher's exact test, and Wilcoxon rank sum test, as appropriate. RESULTS: Ninety-eight patients underwent cardiac transplantation during the study period (87 men, mean age 49 years, 46 ischemic etiology). Of these, 48 were bridged with HeartMate VAD (20 patients received vented electric device, 28 received pneumatic device). Nineteen percent of VAD patients had a peak pretransplant PRA > or =10% vs 2% of patients without VAD (p = 0.014). PRA > or =10%, use of VAD, or duration of VAD support did not predict development of humoral rejection. Use of VAD did not predict development of cellular rejection or allograft vasculopathy. VAD use was not associated with sudden death after heart transplantation. In the entire group of 98 patients, neither humoral nor cellular rejection predicted development of allograft vasculopathy. Longer ischemic time correlated with increased cellular rejection and humoral rejection after transplantation (p = 0.01). CONCLUSIONS: Some patients bridged to cardiac transplantation with VADs have increased PRA before heart transplantation, but this does not appear to translate into increased risk of either humoral or cellular rejection after transplantation or development of allograft vasculopathy as detected by coronary angiography.

Female↗
PubMed2001

Effect on polyomavirus T-antigen function of mutations in a conserved leucine-rich segment of the DnaJ domain.

The N-terminal part of the mouse polyomavirus T antigens contains a highly conserved segment (-LLELLKL-), including amino acid residues 13 to 19. The sequence motif is predicted to form alpha helix I in the DnaJ domain of the T antigens. Four mutants with conservative substitutions of amino acid residues 13 and 14 were constructed. Of the four substitutions, L13M, L13I, L13V, and L14V, only L13V resulted in a phenotypic change. In transfected mouse cells, L13V large T antigen showed a more than 100-fold-reduced viral DNA synthesis. The viral replication could not be rescued by cotransfection of the cells with DNA expressing small t antigen or a large T antigen truncated at the C terminus that would compensate for a defect in host cell stimulation. In contrast to the effect on DNA replication, the L13V substitution in large T antigen did not prevent complex formation with Hsc70 and the Rb protein. Also, the activity of the protein in transactivation of transcription from the adenovirus E2 promoter was unimpaired, showing that the transcription factor E2F was released from pRb. The L13V substitution also caused a defect in small t antigen. However, this phenotypic change was due to protein instability. In contrast, middle T antigen with the L13V substitution remained stable and functional in cellular transformation. Together, the data show that the effect of the L13V substitution did not abrogate the Hsc70 interaction of the DnaJ domain. However, it is possible that the substitution of amino acid residue 13 affected specific DnaJ functions of large T antigen.

3T3 Cells↗
PubMed1995

Existence of memory in ion channels.

AIM: To explore the existence of memory in Ca(2+)-dependent K+ channels of cultured aortic smooth muscle cells (ASMC) and voltage-dependent K+ channels of clonal pheochromocytoma (PC12) cells. METHODS: Calculating the sample auto-correlation functions based on the digitized signals or the 0-1 series corresponding to closing and opening of the channels after routine evaluation, rather than the sequence of sojourn times. RESULTS: The sample auto-correlations showed a decreasing trend with elapse of time, stable to repeated observations under the same conditions and sensitive to treatments. CONCLUSION: The attribute of memory exists in some single channels as an intrinsic feature of them, independent of any extrinsic assumptions on missing observations due to limited time resolution.

Animals↗
PubMed1994

[Preserving intestinal function after severe burn injury].

To study the changes of the bowel-barrier function and its preservation, we developed a new animal model. A specially bred miniswine (Guizhou species) was used with multiple catheterizations for sampling different blood from portal, inferior mesenteric as will as jugular (central) veins. The animals were sustained with 30% III burns of TBSA 7 days after catheterization and divided randomly into early feeding (EF) group, given a complete diet beginning from 2 hours postburn (n = 6) and delayed feeding (DF) group, given the same diet initiating on 4 days postburn (n = 6). The results indicated that the bowel-barrier function was weakened significantly early postburn so that the translocation of both endotoxin and bacteria from the gut to portal vein was evidently increased. However, improving the intestinal mucosa ischemia, preserving mucosal mass and maintaining bowel-microecological balance through early enteral feeding, as revealed in this study, could enhance the barrier function, and the translocation of bacteria and endotoxin would be thus decreased to some extent.

Animals↗
PubMed1994

[Severe burn injury: glucose absorption and early enteral nutrition].

We investigated the changes of glucose absorption and the effect of early enteral nutrition after severe burn injury. A new animal model was developed with a specially bred miniswine (Gui Zhou species) to which multiple catheterizations were applied for sampling different blood from the portal, inferior mesenteric as well as jugular (central) veins. The animals were sustained with 30% III burns of TBSA 7 days after the catheterizations and divided randomly into early feeding (EF) group, given a complete diet beginning from 2 hours postburn, and delayed feeding (DF) group, given the same diet on 4 days postburn. After burn injury, glucose absorption was significantly decreased, but the absorption was much lower in group DF than that in group EF. However, the intestinal ability of absorbing nutrients was not attenuated greatly, and the reduction of portal blood flow was attributed to the decrease of absorption of nutrients. Early enteral feeding can increase portal blood flow obviously.

Animals↗
PubMed1991

Enhancer effect of bovine papillomavirus E2 protein in replication of polyomavirus DNA.

In polyomavirus, both transcription from the early promoter and viral DNA replication initiated at the origin of DNA replication is controlled by binding of proteins to the enhancer region. We have developed a simple model system to study the role of an enhancer binding factor in the initiation of polyomavirus DNA replication. A reporter plasmid was constructed which has the enhancer region replaced by two binding sites for a transcription factor, the E2 protein encoded by bovine papillomavirus type 1. Co-transfection of COP 5 cells which express polyomavirus large T-antigen, with the reporter plasmid and an E2 expression plasmid, resulted in E2-dependent stimulation of replication of the reporter plasmid. The activity of several E2 mutants was also analysed. Mutant proteins with decreased activity in transcriptional trans-activation, resulting from impaired DNA binding or other defects, were found to have quantitatively similar reductions of activity in viral DNA replication. The results suggest that the E2 protein activates transcription and polyomavirus DNA replication by similar mechanism(s).

Antigens, Polyomavirus Transforming↗
PubMed1989

Pathohistogenetic approach on the etiology of Yunnan tin miner's lung cancer.

Pathological observation was made in 100 surgically resected lung cancers of Yunnan tin miners: peripheral type 44 including 9 scar cancers; central type 56, 27 of whom were early lung cancer, with limited initial loci in a well defined area. On the basis of dust retention in original sites of lung cancer and results of X-ray microanalysis, a scheme for calculating the relative probability of causation is formulated. The result of calculation shows that the contribution of exposure to radon daughters is about 7 times that of ore dust retention in the etiology of Yunnan tin miner's lung cancer.

Adenocarcinoma↗
PubMed1989

[An animal model of pump-controlled gastroenteric feeding].

A model for the study of gastroenteric feedings was established in guinea pigs. The model consists of guinea pig with gastrostomy tube and pump-controlled continuous enteral infusion system, with a swivel between the gastrostomy tube and pump system, so that the guinea-pig could move freely in the cage during the experimental period. We used this model for continuous gastroenteric feeding study lasting 2 weeks, and the mortality of animal was low. It is simple, easy to operate, inexpensive and suitable for the experiment of gastroenteric feeding.

Animals↗