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Background: Critically ill patients are at high risk for developing venous thromboembolism. The objective of this study was to determine the prevalence of, and risk factors for, lower extremity deep vein thrombosis (DVT) among critically ill surgical patients in Thailand., Materials and Methods: Patients older than 15 years who were admitted to a surgical intensive care unit (ICU) of a tertiary care hospital were enrolled. Bilateral lower extremity compression Doppler ultrasonographic examination was performed to detect DVT within 14 days of ICU admission. Demographic data, primary disease, operative intervention, co-morbidities, acute physiology and chronic health evaluation (APACHE) II score and the length of ICU stay were tested for association with the presence of DVT., Results: Among the 190 first-time admitted ICU patients with a mean APACHE II score of 9.2 +/- 6.0 (range, 0-29), 20 patients had DVT (prevalence of 10.5%). Thromboprophylaxis was not given to any patient. The only independent and significant risk factor for DVT was a longer ICU stay. Age, sex, APACHE II score, presence of comorbidities and operative intervention were not associated with the presence of DVT., Conclusion: The prevalence of DVT in critically ill patients in a Thai surgical ICU was approximately 10.5%. Further research is needed to evaluate the risks and benefits of venous thromboprophylaxis in Thai patients.

Objective: To compare the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity, Portsmouth adjustment (P-POSSUM), the Hardman index and the Glasgow aneurysm score (GAS) in the prediction of hospital mortality after abdominal aortic aneurysm (AAA) repair., Methods: Medical charts of 146 AAA patients treated between January 1996 and January 2007 were reviewed. The P-POSSUM, Hardman index and GAS were calculated for each patient. The scores were tested and compared for their discriminatory ability to predict hospital death., Results: Of the 146 patients with ruptured and unruptured AAAs (133 underwent open repair, five underwent extra-anatomical bypass and eight underwent endovascular aneurysm repair), 18 died (12%) after AAA repair. The areas under the receiver operating characteristic curves for the GAS, Hardman index and P-POSSUM for predicting hospital mortality were 0.740, 0.730 and 0.886, respectively. The area under the receiver operating characteristic curve for the P-POSSUM was significantly higher than those of other scores., Conclusion: In the present study, the P-POSSUM was the best predictor of hospital mortality for patients undergoing AAA repair.

Objectives: Endovascular aortic aneurysm repair (EVAR) is a current valid treatment option for patients with abdominal aortic aneurysms (AAAs). The success of EVAR depends on the selection of appropriate patients, which requires detailed knowledge of the patient's vascular anatomy and preoperative planning. Three-dimensional (3D) models of AAA using a rapid prototyping technique were developed to help surgical trainees learn how to plan for EVAR more effectively., Method: Four cases of AAA were used as prototypes for the models. Nine questions associated with preoperative planning for EVAR were developed by a group of experts in the field of endovascular surgery. Forty-three postgraduate trainees in general surgery participated in the present study. The participants were randomly assigned into two groups. The 'intervention' group was provided with the rapid prototyping AAA models along with 3D computed tomography (CT) corresponding to the cases of the test, while the control group was provided with 3D CTs only., Results: Differences in the scores between the groups were tested using the unpaired t test. The mean test scores were consistently and significantly higher in the 3D CT group with models compared with the 3D CT group without models for all four cases. Age, year of training, sex and previous EVAR experience had no effect on the scores., Conclusion: The 3D aortic aneurysm model constructed using the rapid prototype technique may significantly improve the ability of trainees to properly plan for EVAR.

Background: Previously, we presented a new, laboratory-based, vascular anastomosis model as a tool to objectively quantify surgical skill. The purpose of the present study was to determine the relation between the outcomes of vascular anastomosis in the laboratory and technical competency, when performing similar vascular anastomoses, in the operating room., Materials and Methods: Twenty-nine resident surgeons-in-training participated in the present study. All residents had at least one previous laboratory training session using the vascular anastomosis model. Then residents had to create a forearm arterio-venous bridge graft in the operating room (OR). Three measures were used to assess technical competency in the OR: completion time of the graft to vein anatomosis, leakage grade across the anastomosis, and the mini-objective structured assessment of technical skills (MOSAT) score. Similar outcomes obtained in the laboratory were used as predictors of OR outcomes. Significant predictors were identified using multiple linear regression and multiple ordinal logistic regression modelling., Results: Worse leakage in the laboratory predicted worse leakage in the OR, longer completion time and worse MOSAT score in the OR. Longer completion time in the laboratory was associated with longer OR completion time, but less leakage. Higher year of training and greater laboratory exposure were related to higher MOSAT score and shorter completion time in the OR, respectively., Conclusions: Completion time and grade of anastomosis leakage measured in the laboratory were predictive of technical competency in the OR. The vascular anastomosis model may be useful for training in clinical surgery.

Background: Vascular anastomosis is a complex task that requires multiple skills. Existing training methods lack the ability to objectively quantify surgical skill. In this study we tested a new vascular anastomosis model for bench training., Materials and Methods: Surgical performance was assessed based on the new vascular anastomosis training model. Thirty- eight subjects were asked to (1) close the end of a 6-mm polytetrafluoroethylene (PTFE) graft, using a continuous suturing technique with 6-0 polypropylene; (2) perform end-to-end and (3) end-to-side anastomosis using the same materials and techniques., Results: The mean age (sd) of all participants was 28.3 (2.1) years. More surgically experienced trainees did better in all measures of technical skill. Although there was a tendency for those with previous experience with the training model to do better in terms of the technical outcomes, these differences were not statistically significant. Multivariable analysis revealed that level of surgical training and type of anastomosis were the only significant factors related to completion time., Conclusions: Our study confirmed the impact of increasing surgical experience on the technical skills of surgical trainees. Trainees with higher levels of training made fewer errors and completed the procedures faster than those with lower levels of training.

Endothelial cells are critical to the integrity of allograft vasculature and can be damaged by alloreactive T cells or soluble mediators of alloreactivity. The biochemical effects of T cell-mediated damage to the endothelial cells have been studied, but not the structural and morphological effects of allo-injury on endothelial cells in the allograft. We utilized an assay that reproduces microvasculature in vitro to study the effect of alloreactivity on endothelial cells. In this assay, endothelial cells are induced into capillary-like networks that simulate microvascular capillaries. We studied the effect of allogeneic T cells and of soluble mediators from both mixed lymphocyte cultures (MLCs) and rejected heart allograft tissue on the in vitro capillaries. We found that both allogeneic T cells and soluble mediators inhibit the formation of the in vitro endothelial capillaries, suggesting that they cause a mild-to-moderate dysfunction of the endothelial cells. The inhibitory effect of the soluble mediators seems to be mediated, at least partly, by IFN-gamma, since this effect was prevented by antibody to IFN-gamma. Furthermore, pre-incubation of the in vitro capillaries with IFN-gamma appeared to magnify the effect of allogeneic T cells, as shown by a complete breakdown of well-formed in vitro capillary networks. Our experiments suggest that the in vitro capillary-tube model reflects structural injury to allograft vasculature by alloreactive T cells and their soluble mediators., (Copyright 2004 Springer-Verlag)

Background: Transplantation of organs leads to several physiologic changes in the recipients who, during their anephric state on chronic hemodialysis, have increased total body water and several electrolyte imbalances. Several abnormal parameters are observed in the physiology of the renal recipient. The central venous pressure (CVP) in the recipient invariably declines despite vigorous fluid resuscitation for reasons that are not clear at the present time., Material/methods: We studied 77 kidney transplants retrospectively, in which we observed a significant decline in central venous pressure (CVP) in the immediate posttransplant period. This phenomenon occurred despite aggressive fluid management and positive fluid balances averaging nearly four liters. Our analysis included the time course of the phenomenon itself as well as a detailed comparison of various parameters in the recipient and the renal graft for possible correlation with this consistent decline in CVP., Results: Neither the absolute CVP nor the drop in CVP appeared to influence the rate of ATN. Interestingly, we found that the kinetics of the decline in CVP were remarkably similar in recipients of both cadaveric and living-related kidneys., Conclusions: This finding suggests that the reperfusion injury or a related effect may be responsible for the clinical phenomenon presented in this study.

Background: Renal transplant rejection cannot be diagnosed with certainty by non-invasive techniques. These techniques lack the specificity to differentiate rejection from other causes of renal dysfunction such as ATN and calcineuria toxicity. Since rejection involves lymphocytes, which the other courses of dysfunction do not, radiolabeling lymphocytes is an attractive technique to diagnose rejection non-invasively., Material/methods: We report our experience with this technique in a pig model of renal transplantation. We studied two groups of pigs, one with renal autografts and the other with allografts. We optimized radiolabeling of lymphocytes and also the technology for detection of these lymphocytes. The uptake of the radiolabeled lymphocyte was compared between the two groups by surface detection and, at the end of the experiment, with scintigraphy of renal tissues., Results: Despite adequate labeling and viability of lymphocytes, only 1-2% of injected lymphocytes 'homed' to the renal grafts. Furthermore, although the detection technology was optimized, a poor signal to noise ratio interfered with the detection of the labeled lymphocytes. Due to these problems rejection could not be differentiated from ATN in this model., Conclusions: We conclude that increasing the specific activity of the lymphocytes and improving the signal to noise ratio will enhance the specificity and sensitivity of this technique and facilitate non-invasive diagnosis of rejection.

Background: Herbal products are increasingly used for their effects on the immune system. Milk Thistle, a commonly used herbal product is known to inhibit growth of certain tumors, although the mechanism of this effect remains unknown. Previously we have shown that Milk Thistle extracts stimulate neurons in culture. Since other drugs that affect the neuronal; system also affect the immune system, we investigated the effects of Milk Thistle on the immune system., Material/methods: Standardized Milk Thistle extract was studied in murine lymphocyte proliferation tests using Concanavalin A (ConA) as mitogen for non-specific stimulation and mixed lymphocyte culture (MLC) as allospecific stimulation. Th1 and Th2 cytokine levels in MLC were assayed by two antibody capture ELISA technique. All tests were performed in triplicate and repeated twice., Results: We found that Milk Thistle is immunostimulatory in vitro. It increased lymphocyte proliferation in both mitogen and MLC assays. These effects of Milk Thistle were associated with an increase in interferon gamma, interleukin (IL)-4 and IL-10 cytokines in the MLC (table). This immunostimulatory effect increased in response to increasing doses of Milk Thistle., Conclusions: Our study has uncovered a novel effect of milk thistle on the immune system. This immunostimulatory effect may be of benefit in increasing the immunity to infectious diseases.

Trauma and injury to transplanted organs in the early post-transplant period are significant factors that affect long-term graft survival. Fetal isoforms of actin are integral members of the immediate early gene family and are expressed in response to free radical injury. We therefore studied actin gene expression in heart transplantation to determine if reperfusion injury activates fetal isoforms of actins. Heterotopic cardiac transplantations were performed in mice. mRNA was extracted from allo- and isografted hearts as well as from normal hearts and spleen. Northern hybridization with actin cDNA to alpha and beta/gamma actin mRNA was performed and analyzed by densitometry. The beta/gamma actin gene expression in the transplanted hearts was found to be significantly elevated within 48 h after transplantation. Analysis of beta/gamma actin gene expression in isografts substantiates the possibility of de novo increase in actin expression. Our studies demonstrate for the first time that fetal isoforms of actin are induced in the allograft heart after transplantation.

Although, major histocompatibility complex (MHC) class II antigen expression in allografts is thoroughly studied, regulation of the genes for these antigens is not fully understood. The graft-specific MHC class II genes are potentially important in determining the immunogenicity of graft but their detection in a mixed-cell population such as in the allograft would require unambiguous differentiation of graft-specific class II expression from those in host lymphoid cells. With an oligonucleotide probe that specifically hybridizes to I-Ab mRNA from H-2k haplotype mice, we have studied I-A gene expression in cardiac allografts heterotopically transplanted from B10.Br (H-2k) to B10.D2 (H-2d) mice. Normal B10.Br hearts do not have appreciable I-Ab transcripts as determined with this probe, but 4 days after allografting, a substantial increase in I-Abk messenger RNA (mRNA) content was noted in the allografted hearts which persisted for the next 2 days and then decreased concomitant with destruction of the heart. The increase in I-Abk mRNA preceded the expression of surface Iak antigens on dendritic and endothelial cells in the allograft. These data indicate increased transcription of the I-Ab gene in cells of graft origin suggesting that transcriptional regulation is the initial mechanism for expression of class II genes in allografts. The sustained rise in graft-specific class II mRNA also seen in these allografts suggests that increased mRNA stability may be another mechanism for the increased density of class II antigens in allografts undergoing rejection.

In a previous study [(1984) J. Cell Biol. 98, 725-731] we showed that the level of human MHC, HLA antigens on A431 carcinoma cells is reduced after these cells bind epidermal growth factor (EGF). Here we use flow cytometry to determine the effects of various doses and times of EGF treatment on HLA expression. We then show that the reduction in HLA expression is associated with a reduction in the level of phosphorylation of immunoprecipitable surface HLA antigens, although longer exposure of cells with EGF increased both surface HLA expression and their phosphorylation levels. Lateral diffusion of HLA antigens is lower in EGF-treated than in control cells. The lower diffusion coefficients measured may be causally related to the decreased phosphorylation of HLA antigens.