Effect of Water on the Structure and Stability of Hydrogen-Bonded Oxalic Acid Dimer.

As the simplest and most abundant dicarboxylic acid in the atmosphere, oxalic acid (OA) not only plays a key role in aerosol nucleation, but also acts as a prototypical compound for the investigation of intra- and intermolecular hydrogen-bonding interactions. A systematic theoretical study on the hydrated OA dimers performed by using DFT at the M06-2X/6-311++G(3df, 2p) level is discussed herein. The properties of hydrogen bonds in clusters are inspected through topological analysis by using atoms in molecules (AIM) theory. The most stable OA dimer involves a cyclic structure with two intermolecular hydrogen bonds. Calculations show that one H2 O has a slight effect on the hydrogen bonds, whereas two water molecules weaken and three water molecules break the two intermolecular hydrogen bonds between OAs. Furthermore, there are no hydrogen-bond interactions between OAs in almost all stable clusters as the number of H2 O molecules increases to four and five. Additionally, ionization and isomerization of OA through water-assisted proton-transfer phenomena are observed in tetra- and pentahydrates. This work provides new insights into the conversion of anhydrous OA into hydrated clusters that are helpful for further understanding the atmospheric nucleation process and nature of hydrogen bond.

[Tumor microvascular density detected by anti-CD105 and anti-CD34 in hepatocellular carcinoma patients and its predictive value of tumor recurrence after liver transplantation].

OBJECTIVE: To investigate the clinical significance of tumor microvascular density (MVD) detected by anti-CD105 and anti-CD34 as a predictor of recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT). METHODS: One hundred and twelve (100 with adjacent nontumorous area) patients with HCC who underwent LT between Jan. 2001 and Dec. 2006 were included in this retrospective study. Paraffin blocks of tumor tissue and adjacent nontumorous tissue were used for immunohistochemical study. MVD of HCC was evaluated by anti-CD105 monoclonal antibody and anti-CD34 monoclonal antibody. RESULTS: The immunohistochemich staining showed CD34 strongly positive expressed in the tumor area with tumor mature vasculature, and CD105 strongly positive expressed in adjacent nontumorous area with tumor newly formed vessels. Univariate analysis using chi-square test showed portal vein tumor thrombus (PVTT), pTNM stage, MVD-CD105 expression in adjacent nontumorous area, tumor size and serum AFP level were significantly associated with HCC recurrence after LT (P < 0.05). Multivariate analysis by Cox's regression model showed MVD-CD105 expression in adjacent nontumorous area and PVTT still remained significant correlation with recurrence of HCC after LT (P < 0.05), and MVD-CD105 in adjacent nontumorous area was significantly correlated with PVTT (r(s) = 0.257, P = 0.01), pTNM stage (r(s) = 0.350, P = 0.000), as well as serum AFP level (r(s) = 0.208, P = 0.038). CONCLUSION: The anti-CD105 mAb is an ideal tool to quantify new microvessels in HCC. MVD-CD105 expression in adjacent nontumorous area may be used as an additional factor for the identification of patients at risk for post-transplant recurrence.

[An analysis of long term prophylaxis of virus recurrence with antiviral treatment in HBV infected liver transplant recipient patients].

OBJECTIVE: No optimal prophylactic protocol of hepatitis B immunoglobulin (HBIG) combined with nucleos(t)ide analogue for HBV recurrence has been established yet. By investigating the alterations of HBV markers in HBV related liver disease patients, recipients of a liver transplant, under lamivudine or/and HBIG prophylaxis, we aim to explore the possible HBV recurrence mechanism involved and to find a new option in the prophylaxis of HBV recurrence and to tailor individualized therapy. METHODS: Serial liver biopsy specimens and sera were obtained intraoperationally and at definite time points during follow-up. ELISA and chemiluminescent microparticle immunoassay, HBV DNA fluorescent quantification, immunohistochemistry staining and HBV DNA in situ hybridization were performed. Alterations of HBV markers in specimens of 96 liver transplant recipients were investigated retrospectively. RESULTS: All 17 cases had HBV recurrence (median 37 months) which occurred in the follow-up period after liver transplantation. The overall actual HBV recurrence rate at 2 years was 22% with a significant difference between that of the active and inactive groups (P<0.05); 82.4% HBV recurrence took place within the first 3 years after the operation, and the recurrence ratio of first 3 years to 3 years later after transplantation was 4.7 (P<0.01). The HBV DNA positive patients accounted for 78.6% of the total number of recurrences within the first 3 years. HBcAb and HBeAb positive rates went down with time, but their positivity remained. CONCLUSION: HBV recurrence happens after liver transplantation. In inactive HBV replicative patients with strictly combined prophylaxis and availability of other medications and using 3 years after liver transplantation as a point of time, we think that tapering down the dosage of HBIG and tailoring individualized treatment methods based on virological and immunological situations of each recipient are worth trying.

[Explorative study on mechanism and drug intervention for chronic allograft nephropathy induced by renal ischemia-reperfusion injury].

OBJECTIVE: This study is aiming to investigate the mechanism and drug intervention of chronic allograft nephropathy (CAN) induced by renal ischemia-reperfusion injury. METHODS: The closed colony strain Sprague-Dawley (SD) and Wistar Rats were used as donor and recipient, respectively. Orthotopic kidney transplantation was performed following the procedure of our previous study. The rats were divided into five groups: Group A only received CsA with 10 mg/(kg x d); except CsA, Group B,C,D received Yi Sheng injection with 4 mg/(kg x d), 8 mg/(kg x d), and MMF (20 mg/(kg x d)], respectively. Group E was control group. According to Banff standard, the serum creatinine (SCr) level and pathological change of rat grafted kidney were observed at the 4th, 8th and 12th weeks post-transplantation. The immunohistochemistry and real-time fluorescence quantitative polymerase chain reaction were used to comprehend the localization and expression of TGFbeta1 and Smad2, 7 in the transplant kidney. RESULTS: Compared with the lower dosage group, the differences of SCr level and pathological changes of CAN at all the time points after 8th week were statistically significant in the high dosage Yi Sheng group. It was showed that the Yi Sheng injection had the protective effect on CAN with a dose-dependent fashion. After transplantation, the rat kidney-sclerosis model showed that the up-regulated expressions of TGF-P, and Smad2 and the down-regulated expression of Smad7 in Group A and Group B were statistically significant, which meant that the difference was obvious when Group A compared with the other 4 groups. The expressions of TGF-beta1, and Smad2 were strongly positive in tubular epithelial cell, interstitial cell and glomerulus, while the expression of Smad7 was weak. Thickening of endovascular could significantly be inhibited in high dosage of Yi Sheng and MMF group. CONCLUSION: The up-regulated expressions of TGF-beta1 and Smad2 and the down-regulated expression of Smad7 may accelerate the progression of CAN alone or with immune factors. The traditional Chinese medicine Yi Sheng injection and MMF can down-regulate the expression of TGF-beta1 and Smad2 and block the down-regulated expression of Smad7, which may postpone and lessen the progression of CAN.

Clinical and pathological characteristic of metastatic malignant mesothelioma initially diagnosed by lymph node biopsy.

BACKGROUND: It is a great challenge for pathologists to initially diagnose metastatic malignant mesothelioma (MM) by the lymph node biopsy without any history of primary MM. Because the onset of MM is hidden and the metastatic MM in lymph node is relatively uncommon. Besides, morphologic and immuohistochemistry features of MM are similar to other tumors. METHODS: In order to improve the initial diagnostic accuracy of metastatic MM from LN biopsy and to reduce or avoid the possibility of missed diagnosis or misdiagnosis, we had collected the clinical and pathological data of the metastatic MM cases in our department, and summarized the characteristics of morphological, immunohistochemical and fluorescence in situ hybridization (FISH) results. RESULTS: Seven patients (4 males and 3 females) with 21-73 year-old had been included in our study. Six cases showed serous cavity effusion, serosal thickening and systemic multiple lymph node enlargement. The "moderate, nice" tumor cells were arranged in variable patterns. Mitosis was hardly to be found and necrosis was absent. Four immunohistochemical staining panels and FISH detection had been used for diagnosis and differential diagnosis of MM. All cases expressed broad-spectrum epithelial markers and at least 2 mesothelial-cell-origin markers. None were positive for specific-tissue-origin markers, and all cases were diagnosed of malignancy according to immunohistochemical markers and detection of pl6 gene deletion. CONCLUSION: It is necessary for us to keep our awareness of metastatic MM in lymph node. Correct diagnosis of MM metastasis by lymph node biopsy were based on detailed understanding of the clinical manifestation and the image data, careful observation of morphologic characteristics, and properly using immunohistochemical markers or FISH detection if necessary for diagnosis and differential diagnosis.

Dynamic CT Evaluation of Tumor Vascularity in Renal Cell Carcinoma.

OBJECTIVE: The purpose of our study was to evaluate the correlation between the enhancement parameters of dynamic CT; the carcinoma tissue microvessel density (MVD, a hotspot method to provide a histologic assessment of tumor vascularity); and tumor nuclear grade in renal cell carcinomas. SUBJECTS AND METHODS: Twenty-four patients with histologically diagnosed renal cell carcinoma underwent dynamic enhanced CT. Enhancement parameters, slope of the time-density curve, the density difference before and after tissue enhancement (deltaH), tissue blood ratio (TBR), and area under the time-density curve (AR), were calculated for all lesions. Pathology slides corresponding to the CT plane were stained using mouse antihuman CD34 monoclonal antibody and H and E. Fuhrman nuclear grade was used. Vascular hot spots of microvessels were recorded. Spearman's rank correlation was performed to determine the strength of the relationship between enhancement parameters, MVD determinations, and tumor nuclear grade. RESULTS: MVD with CD34 staining revealed uneven distribution of positively stained vascular endothelial cells in renal cell carcinoma lesions. Heterogeneous distribution of contrast enhancement was seen among and within individual tumors. The tumors appeared as uneven patterns on time-density curves of renal cell carcinoma lesions. Enhancement parameters of H (median, 21.0 H; range, 2.2-105.8 H), TBR (median, 39%; range, 10.7-154.7%), AR (median, 1.58 H x sec; range, 0.23-3.67 H x sec), and slope (median, 2.76; range, 0.53-6.76) varied greatly. Renal cell carcinoma tissue MVD significantly correlated with all enhancement parameters of dynamic CT. The correlation coefficients (r) were 0.62, 0.54, 0.55, and 0.44, respectively, for delta H, slope, TBR, and AR (p < 0.0 5). All enhancement parameters did not significantly correlate with tumor nuclear grade. They were not predictive of nuclear grade. CONCLUSION: Enhancement parameters of dynamic CT may be suited to evaluate tumor vascularity in vivo. Dynamic enhanced CT images may reflect the heterogeneity of tumor angiogenesis on the basis of the correlation between enhancement parameters and MVD of renal cell carcinoma.

Is autologous or heterologous pericardium better for valvuloplasty? A comparative study of calcification propensity.

Pericardial calcification is detrimental to the long-term durability of valvuloplasty. However, whether calcification susceptibility differs between heterologous and autologous pericardium is unclear. In this study, we compared the progression of calcification in vivo between autologous and heterologous pericardium. We randomly divided 28 rabbits into 4 equal groups. Resected rabbit pericardium served as autologous pericardium, and commercial bovine pericardium served as heterologous pericardium. We subcutaneously embedded one of each pericardial patch in the abdominal walls of 21 of the rabbits. The 7 control rabbits (group A) received no implants. The embedded samples were removed at 2 months in group B, at 4 months in group C, and at 6 months in group D. Each collected sample was divided into 2 parts, one for calcium-content measurement by means of atomic-absorption spectroscopy, and one for morphologic and histopathologic examinations. When compared with the autologous pericardium, calcium levels in the heterologous pericardium were higher in groups B, C, and D (P <0.0001, P <0.0002, and P <0.0006, respectively). As embedding time increased, calcium levels in the heterologous pericardium increased faster than those in the autologous, especially in group D. Disorganized arrangements of collagenous fibers, marked calculus, and ossification were seen in the heterologous pericardium. Inflammatory cells-mainly lymphocytes and small numbers of macrophages-infiltrated the heterologous pericardium. The autologous pericardium showed a stronger ability to resist calcification. Our results indicate that autologous pericardium might be a relatively better choice for valvuloplasty.

Lamivudine prophylaxis of liver allograft HBV reinfection in HBV related cirrhotic patients after liver transplantation.

BACKGROUND: Liver allograft hepatitis B virus (HBV) reinfection and hepatitis B (HB) recurrence jeopardize the long-term survival of recipient and liver allograft. Lamivudine has been referred as a novel antiviral agent against HBV in HBV cirrhotic patients even in liver transplantation setting. We assessed the prophylatic effect of lamivudine on liver allograft HBV reinfection and clarified the dynamic changes of HBV markers in HBV related decompensated liver cirrhosis after liver transplantation. METHODS: Twenty-five recipients were divided into three groups: HBV active replication group (15 recipients), HBV inactive replication group (7), and control group (3). 100 mg/d lamivudine was administered preoperatively except in the control group. The HBV markers of serial sera and liver biopsy samples of the 25 recipients were evaluated regularly with enzyme-linked radioimmunoassay, HBV DNA fluorescent quantitative assay, immunohistochemical staining, labelled streptavidin biotin (LSAB) and digoxin labelled HBV DNA hybridization in situ. The dynamic alternation of HBV markers under lamivudine prophylaxis was observed. RESULTS: In the HBV active replication group who had received lamivudine 2 weeks before liver transplantation, serum HBV DNA positive converted to negative by 80%. HBsAg of all recipients disappeared after liver transplantation, but corresponding antibodies of HBV appeared within one week after the operation. HBsAb 9/15, HBcAb 13/15 and HBeAb 11/15 appeared and subsided gradually within 24 weeks. HBV DNA in sera was kept negative; HBsAg, HBcAg and HBV DNA hybridization in situ of liver biopsy samples remained negative after use of lamivudine. Ten of the 15 recipients showed clearance of HBV, and per se HBV markers were undetectable both in serum and liver biopsy samples between 12 to 44 weeks (24 weeks on average). The 1-, 2-year survival rates were 83% in this group. Two of the 15 recipients developed HBV allograft reinfection or recurrence of hepatitis 2 years after lamivudine monoprophylaxis (2/15, 13.3%). In the HBV inactive replication group, the outcome was similar to that of the HBV active group. The HBV antibody frequency was HBsAb 4/7, HBcAb 6/7, and HBeAb 2/7. Three of 7 recipients showed HBV clearance both in sera and liver biopsy samples, whereas in the control group all 3 recipients developed HBV allograft reinfection and recurrent hepatitis 8, 10, 12 months postoperatively; one of them died of fibrosing cholestatic hepatitis, and the remaining 2 recovered after additional lamivudine therapy. The overall allograft reinfection rate was 9.1% (2/22) and the overall 1-, 2-year survival rates were 87% in the lamivudine prophylaxis group. CONCLUSIONS: Lamivudine prophylaxis can prevent effectively liver allograft from HBV reinfection in patients with HBV-related decompensated liver cirrhosis even in HBV active replication recipient after liver transplantation. Its long-term outcome remains to be studied.

Dynamic alteration of HBV markers on active HBV replicative recipients after liver transplantation: a preliminary report.

OBJECTIVE: To investigate the dynamic alternations of HBV markers of active HBV replication recipients receiving lamivudine prophylaxis after liver transplantation. METHODS: Serial liver biopsy samples and sera were obtained from 15 recipients and examined with enzyme-linked radioimmunoassay for HBsAg, HBeAg, HBsAb, HBcAb and HBeAb, and fluorescent quantitative assay for quantitation of HBV DNA in serum. Immunohistochemical staining of HBsAg, HBcAg and HBV DNA hybridization in situ were used to detect HBV markers in liver biopsy samples. RESULTS: 100 mg lamivudine taken orally every day for 2 weeks before transplantation enabled 12 (80%) of 15 active viral replication recipients (HBV DNA positive) to converse to HBV DNA negative. HBsAb, HBcAb and HBeAb in serum emerged in 1-2 weeks after liver transplantation, and disappeared gradually within 6 months; HBV DNA fluorescent quantitative assay showed constant negativity in serum. Immunohistochemical staining of HBsAg, HBcAg and HBV DNA hybridization in situ in liver biopsy samples showed negative results synchorously. Eight of the 15 HBV active replication recipients lost HBV markers thoroughly both in serology and tissue staining as well as HBV DNA hybridization in situ of serial liver biopsy samples from 12 to 44 weeks after liver transplantation. Should any of HBsAg, HBeAg in serology and HBsAg, HBcAg in immunohistochemical staining was positive, or HBV DNA detectable in serum, or HBV DNA hybridization in situ in liver tissue positive, allograft HBV reinfection or De novo liver allograft infection could be diagnosed. Furthermore, if associated with elevation of ALT and bilirubin, the diagnosis of HBV hepatitis recurrence could be established. CONCLUSION: Allograft HBV reinfection or De novo liver allograft infection in active viral replication recipients could be prevented with lamivudine regimen, and further clearance of HBV may be possible if proper measures are taken.

[Investigation on the alteration of hepatitis B virus (HBV) markers in liver allograft of HBV related recipients in perioperative period].

OBJECTIVE: To investigate the alteration of HBV markers in liver allograft of HBV related recipients pre and post liver transplantation under Lamivudine or combination of Lamivudine with HBIG prophylaxis and explore the mechanism of HBV de nova infection in liver allograft after orthotopic liver transplantation, as well as seek to establish a optimal prophylactic protocol. METHODS: The serial liver biopsy specimens of 90 liver allograft and sera of 78 liver transplant recipients during operation and after 1 week, 1 month, 3 months, 6 months, 12 months, 24 months post transplantation have been collected and detected for HBV markers with enzyme-linked radioimmunoassay, fluorescent quantitative assay for HBV-DNA in serology and with immunohistochemistry stain, HBV-DNA in situ hybridization in histology for detection of HBV markers in liver allograft samples. RESULTS: Whether recipients with active replicative or inactive replicative HBV preoperatively, none of positive HBV-DNA, HBsAg and HBcAg in 100% liver biopsy specimens with HBV-DNA hybridization in situ and immunohistochemistry stains in histology within 2 hours after reperfusion. CONCLUSION: Whatever HBV replicative status the recipients have before surgery, no evidence of HBV particles direct invasion to the liver allograft from HBV related cirrhotics during operation under current prophylactic measures. However, the further supposed mechanism and its significance in HBV de nova infection of liver allograft remained to be disclosed further.

[Clinical and pathological analyses of lipoprotein glomerulopathy].

OBJECTIVE: To investigate the clinical and pathological characteristics of lipoprotein glomerulopathy. METHODS: We retrospectively analyzed 3 cases of lipoprotein glomerulopathy. RESULTS: The 3 patients, 1 male and 2 females, were young Hans. They were admitted to our hospital because of edema. Patient 1 had a positive family history. Her proteinuria ranged between 0.8-1.5 g/d, her serum albumin levels were below the normal lower limit, and she was afflicted with anemia. Patient 2 was found having slightly increased serum creatinine, hypertension, and increased total cholesterol and triglyceride level. The kidneys of patient 3 were enlarged. Increments of glomerular size and capillary lumen space were observed under microscope. Bioptic specimens of the patients' kidneys displayed extensive prominent lucent casts in the capillary lumen, which were stained as pale mesh-like substance and were not stained by silver impregnation. Immunofluorescence microscopy revealed faint immunoglobulin deposit. These casts were stained positive for apoE. CONCLUSION: Lipoprotein glomerulopathy is pathologically characterized by extensive glomerular capillary casts which are stained positive for apoE, and clinically it is characterized by edema, proteinuria, hypoalbuminaemia and anemia.

[A new rat model of transplant kidney-sclerosis accelerated by prolonged cold ischemia time].

OBJECTIVE: To establish an accelerated animal model of the chronic renal allograft dysfunction in rat. METHODS: Kidney transplantation was performed from SD to Wistar strain (allogeneic) according to the procedure of Kamada with some modification. Before the transplantation, the kidney was preserved in 0-4 degrees C heparin sodium chloride solution for prolonging the one hour. The serum creatinine level and pathological change of transplant kidney were observed in the 2nd, 4th, 6th, 8th and 12th weeks post-transplantation. RESULTS: After transplantation, the serum creatinine level of recipient rats obviously increased in the 6th week and the pathologic changes of chronic nephropathy evidently appeared in the 8th week when compared to those of the control group with non-reinforcement I/R injury; a statistically significant difference was noted. CONCLUSION: It is simple and feasible to establish a rat model of (SD-->Wistar) transplant kidney-sclerosis accelerated by prolonging I/R injury.

Endolymphatic sac tumor with von Hippel-Lindau disease: report of a case with atypical pathology of endolymphatic sac tumor.

The authors described a case of a patient with co-existing endolymphatic sac tumor (ELST) and hemangioblastoma in the posterior cranial fossa, which belonged to a subtype of Von Hippel-Lindau (VHL) disease confirmed by the test of VHL-gene. The signs in this 42-year-old female included intermittent headache and dizziness. Imaging revealed a giant mass in the right cerebellopontine angle (CPA) region and another lesion in the left cerebellar hemisphere. The results of biopsy after two operations confirmed the diagnosis respectively. Both of the tumors were resected totally. Nevertheless, we had to confess the misdiagnosis as vascular tumor instead of ELST at the initial diagnosis because of the rarity of ELST associated with atypical histological characteristics. The purposes we reported this case were to describe the atypical pathological feature of ELST and the mutation of germline VHL not mentioned in previously literature, furthermore, to foster understanding of ELSTs with the avoidance of the similar misdiagnosis as far as possible in future.

Theoretical studies on novel main group metallocene-like complexes involving planar hexacoordinate carbon eta6-B6C2- ligand.

The geometric structures for a novel series of main group 1 and 2 metal atom complexes with planar hexacoordinate carbon dianion (eta6-B6C)2- ligand, involving metallocene-like, K[(eta6-B6C)Ca]n(eta6-B6C)K (n = 1-3) and [(eta6-B6C)Ca]n(eta6-B6C)2- (n = 1, 2), as well as relative pyramidal [(eta6-B6C)M]i- (M = Na, K, and CaCl, i = 1; M = Ca, i = 0) and bipyramidal (eta6-B6C)(CaCl)2, have been optimized to be the local minima on the corresponding potential hypersurfaces at the B3LYP/6-311+G(d) level of theory. Natural bond orbital analysis indicates that the electrostatic interaction between the metal ions and the planar hexacoordinate carbon B6C2- rings plays a crucial role in stabilizing these highly symmetrical complexes. The pi-d interaction in Ca-containing complexes also plays an important role in the stabilization of these molecules. It is found that the Ca2+ cation could be considered the best candidate for (eta6-B6C)2- to build ionic organometallic compounds. In these predicted multideck metallocene-like complexes there exist similarities in many structural properties, such as geometry parameters, Wiberg bond indices, natural atomic charges, atomic electronic configurations, and frontier orbital energies, as well as increments of the dissociation energy (to -[(eta6-B6C)Ca]- units and metal cations) for adding one -[(eta6-B6C)Ca]- unit and so on, which suggests that the -[(eta6-B6C)Ca]- unit could be used as a building block to construct more K[(eta6-B6C)Ca]n(eta6-B6C)K chain-type metallocene-like complexes along their sixfold molecular axis.