Large amounts of bubble-chain boron nitride nanotubes were synthesised by annealing an effective precursor. The porous precursor was produced by self-propagation high-temperature synthesis method using Mg, B2O3, amorphous B and Fe2O3 as the starting materials, which played an important role in synthesis of BN nanotubes in large quantities. Samples were characterised by SEM, TEM, HRTEM, X-ray powder diffraction and Raman and Fourier transform infrared spectroscopy. The as-synthesised BN nanotubes revealed periodical bubble-chain structures, having diameters of range 20-200nmand an average length of more than 5 mu m. The effects of temperature, time and the possible mechanism of the growth of the BN nanotubes were also discussed.

Bamboo-like multiwall boron nitride (BN) nanotubes were synthesized via annealing porous precursor prepared by self-propagation high temperature synthesis (SHS) method. The as-synthesized BN nanotubes were characterized by the field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), high-resolution TEM (HRTEM), X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy. These nanotubes have uniform diameters of about 60nm and an average length of about 10μm. Four growth models, including tip, base, based tip and base–tip growth models, are proposed based on the catalytic vapor–liquid–solid (VLS) growth mechanism for explaining the formation of the as-synthesized bamboo-like BN nanotubes. Chemical reactions and annealing mechanism are also discussed.

1Department of General, Visceral And Transplantation Surgery, 2Department ofGastroenterology and Hepatology, University Hospital of Essen, 32Institute of Physiological Chemistry, University Hospital of Essen, 4Department of General, Visceral And Transplantation Surgery

Recently, we raised the hypothesis, that liver regeneration is inversely correlated with parameters of immune activation. This was the reason to test on one hand the effect of thymectomy, which is impairing T-cell maturation and subsequent T-cell activation. As GCSF was reported to have anti-inflammatory activity affecting cytokine release, the effect of the perioperative treatment with GCSF on liver regeneration was investigated in a second approach.

P1229 Aims: Three mechanisms of regeneration were described in the liver. One is the proliferation of mature hepatocytes, which reenter the cell cycle, another proliferation of oval cells which act as hepatic stem cells. Furthermore transdifferentiation of bone marrow derived adult stem cells into hepatocytes has been described lately. This study was designed to investigate the effect of G-CSF on the survival and extent of parenchymal chimerism using a syngeneic rat model of female to male full size liver transplantation (LTx). Methods: Syngeneic gender mismatched liver transplantation was performed in Lew-rats, which were sacrificed after 1w, 4w and 12 weeks postoperatively. Rats in the experimental group were treated with hrGCSF in a dose of 100μg/kg/day from day-5 up to d21 after transplantation, whereas control rats received no treatment. Stem cell mobilization was assessed by WBS and ASDCL-staining for precursor cells in the liver. Fluorescent-in-situ hybridisation was performed on liver samples using a newly developed rat specific y-probe. 50 digital images/animal (600x) were evaluated to determine the rate of transdifferentiated hepatocytes. Results: Treatment of G-CSF did not exert a significant influence on the survival rate after LTx. However, treatment was associated with a higher incidence of biliary complications and an increased histomorphological damage to the bile duct in long term survivors (POW) 12, which was attributed to a presumingly impaired arterial perfusion of the biliary tree. The two-fold increase of WBC in peripheral blood confirmed the mobilizing effect of G-CSF on hematopoietic cells. Its effect on recruitment of HSC to the liver was illustrated by the detection of precursor cells in the portal area of the liver. Y-chromosome positive hepatocytes were detected in low numbers after LTx, suggesting HSC transdifferentiation is a rare event. G-CSF treatment was associated with an earlier occurrence of HSC derived hepatocytes (POW1), a slightly higher number of HSC derived hepatocytes over time as well as a higher incidence of animals per group at each time point. Conclusions: These results suggest that G-CSF might possibly shift the initiation of transdifferentiation to an earlier time point, and might slightly enhance HSC transdifferentiation into hepatocytes, which may be related to the enhanced recruitment of precursor cells to the liver.

Aim: Previous data showed a less favorable outcome for male recipients of female livers after full size liver transplantation. Due to the persistent shortage of organs partial liver grafts are used with increasing frequency. The aim of the present study was to assess the impact of donor gender on partial (small-for-size) liver transplantation using a rat model. Materials and methods: Adult female or male Lewis rats were used as donors and male Lewis rats as recipients. 30% partial liver grafts (POLT) were transplanted orthotopically into recipients. Animals were sacrificed in the postoperative week 1, month 1 and month 3, respectively. Survival rate in each group was observed. All animals underwent complete autopsy. Tissue from all organs was sampled for histological analysis. Results: Animal survival rate after male-to-male (M-M) POLT was 100% (6/6), 100% (6/6) and 75% (6/8), respectively after 1 week, 1 month and 3 month observation. Female-to-male (F-M) POLT resulted in a survival rate of 85% (6/7), 66.7% (4/6) and 37.5% (3/8) at the respective time points. Cumulative survival rate differed significantly (p = 0.029) in both gender combinations as assessed by log rank test (M-M:SVR = 90% (18/20) versus F-M: SVR 62% (13/21). Animals receiving a partial female liver graft died either during the early postoperative period (within 3 weeks) with obvious gross necrosis of liver lobes or relatively late after transplantation (later than 2 months postop) due to bile duct obstruction by sludge and consecutive severe biliary proliferation and considerable fibrotic changes. In contrast, no animal receiving a male partial graft died in the early postoperative period, but 2 animals died of biliary complications later (POD 45 and 61). Conclusion: Gender mismatched transplantation was associated with a significantly lower survival rate and a higher frequency of biliary complications, which might be related to the reported sensitivity of the female liver to ischemic injury, especially in an environment which lacks the female hormones.

Immunity to hepatitis B has been successfully transferred by bone marrow transplantation, but has also occurred after liver transplantation (LTx). This study was designed to analyse the influence of alloreactivity and immunosuppression, on the efficacy of adoptive immune transfer to hepatitis B by liver transplantation. Orthotopic LTx (n = 34) were performed in three rat strain combinations representing different genetic constellations. Donors had been vaccinated twice with recombinant hepatitis B surface antigen while recipients were unimmunized. Half of the allogeneic recipients were immunosuppressed with cyclosporin A. All animals were monitored weekly for the presence of anti-hepatitis B surface antibodies (anti-HBs). Effective anti-HBs titres were detected in 85% (29/34) of liver recipients and lasted from 2 to 10 weeks. Donor titre above >15 000 mIU/mL ensured a 100% seroconversion rate in the recipients. The maximal anti-HBs titre in recipients represented 0.06% approximately 0.76% of the donor titre. Rejection reduced the adoptive immune transfer, which was protected by immunosuppression. These observations suggest that transfer of functionally active donor lymphocytes, deriving from the graft, contributed to the donor-derived immune response in the recipient. Further studies to augment the donor-derived immune response are warranted to ensure a therapeutic effect for the recipient at risk of reinfection.

Adoptiver Transfer von Spenderimmunität auf den Empfänger wurde erstmals nach Knochenmarktransplantation beobachtet. In einer aufsehenerregenden Einzelfalldarstellung wurde 1993 beschrieben, dass es nach der Transplantation von Knochenmark von einem Spender mit durchgemachter Hepatitis B Infektion zu Viruselimination beim Empfänger kam. Aufgrund dieser Ergebnisse wurden systematische experimentelle und klinische Studien durchgeführt, in denen der Transfer von humoraler und zellulärer Immunität sowie das Auftreten einer typischen „Memory-response” nach Booster-Impfung gezeigt wurde. Die Übertragung von Immunfunktionen des Spenders auf den Empfänger mittels einer Organtransplantation wurde in der Vergangenheit zwar gelegentlich aufgrund der negativen Auswirkungen (immunhämolytische Anämie, Erdnussallergie) beobachtet, jedoch nicht in seiner potentiellen Bedeutung für den Empfänger erkannt.

Adoptive transfer of immunity to hepatitis B virus (HBV) is not provoked solely by bone marrow, but also by liver transplantation, although transiently. In the current study, simultaneous bone marrow transplantation, which possibly can increase the number of antibody-secreting cells, was performed to augment the efficacy of transferring HBV immunity. Stimulation of donor-derived immune cells by postoperative vaccination was used to investigate whether a secondary immune response can be induced in recipients. Orthotopic liver transplantation (n = 28), performed in three rat strain combinations representing different genetic constellations, was compared with bone marrow-augmented liver transplantation (n = 21). Donors had been vaccinated twice with recombinant hepatitis B surface antigen (HBsAg). Recipients surviving more than 10 weeks received a boost vaccination. All animals were monitored weekly for the presence of antibodies to HBsAg (anti-HBs). Effective anti-HBs titers were measured in 82% of liver recipients (23 of 28 recipients) and lasted from 2 to 9 weeks. Ninety percent of bone marrow-augmented liver recipients (19 of 21 recipients) seroconverted, with anti-HBs persisting from 2 to 12 weeks. A greater seroconversion rate, prolonged titer duration, and different pattern of titer development were observed in bone marrow-augmented liver recipients, although statistical significance could not be obtained because of the small numbers of comparable animals. Posttransplantation vaccination in recipients of combined grafts did not arouse a typical secondary antibody response, but showed a tendency toward an earlier and stronger response to vaccine in comparison to recipients without immune transfer. Simultaneous bone marrow transplantation showed an augmenting, but limited, effect on humoral immune transfer. Therefore, other potentially promising cellular strategies, such as transfer of in vivo and ex vivo stimulated antigen-specific cells should be pursued further. Improvement of the effect of postoperative vaccination possibly can be achieved by optimizing the immunization protocol.

The incidence of the small-for-size syndrome (SFSS) is inversely correlated to the size of the remnant liver or the partial graft. The relevance of factors besides the absolute liver mass is discussed controversially. It is the aim of this study to test the effect of two different mass ligation techniques in comparison with our newly developed parenchyma-preserving vessel-oriented liver resection technique on the induction of a SFSS after extended 90% liver resection in the rat.Ninety percent liver resections were performed using three surgical techniques, two mass ligation techniques, and a vessel oriented technique. Diagnosis of SFSS was based on the combination of biochemical and morphological criteria on the first postoperative day and was related to the outcome on postoperative day 7 and the regenerative capacity of the liver.Only the use of mass ligation techniques was associated with a low 1-wk survival rate (<40%), more pronounced histomorphological signs of liver damage at 24 h postoperatively, and a delayed onset of hepatocyte proliferation. Histological analysis revealed an extended stump necrosis in the paracaval liver and signs of sinusoidal damage in the remaining caudate lobes as morphological correlates of a putative outflow obstruction as the possible underlying reason. The lesions added up to a high small-for-size score in rats operated according to mass ligation techniques.These results indicate that preservation of functional liver mass and prevention of an outflow obstruction by delicate surgery is essential to prevent a SFSS in a size-reduced liver.

Transfer of hepatitis B immunity occurs upon the transfer of immunologically active cells from the donor to the recipient by means of an organ graft. This has been repeatedly demonstrated for bone marrow and liver transplantations. Evidence is now presented for the transfer of anti-hepatitis B surface antibodies (anti-HBs) after kidney transplantation in rats. Kidney donors from one syngeneic and two allogeneic rat strains were immunized twice with 4 μg of recombinant hepatitis B vaccine. In week 6 after the first vaccination, kidney grafts were transplanted into Lewis (LEW) rats. Half of the recipients underwent daily immunosuppressive treatment with cyclosporin A (CsA). All recipients were vaccinated either after 10 weeks or 1 week postoperatively. Anti-HBs titer was measured weekly. Effective anti-HBs titers (10–227 mIU/ml, lasting for 1–7 weeks) were detected in 86% (25/29) of recipient rats, whose corresponding donors all had a titer above 15,000 mIU/ml. Immunosuppression enhanced the donor-derived immunity in terms of recipient-to-donor titer ratio, maximal titer and titer persistence.

On the basis of the recently recognized potential of hematopoietic stem cells (HSC) to give rise to hepatocytes, we investigated the possibility that HSC could be mobilized and home to the injured liver promoting tissue repair after 50% partial orthotopic liver transplantation (PLTx) in the rat.Using sex-mismatched (female to male) syngeneic SD rats, we performed 50% PLTx or whole orthotopic liver transplantation (WLTx) versus 50% partial hepatectomy (PHx) and sham operation (O). Elements with stem cell markers were detected in peripheral blood (PB) and in the liver. Liver injury and regeneration were estimated. The sex-determining region for Y chromosome gene (SRY) was used to define cell origin by in situ hybridization in liver sections.Comparison of WLTx and PHx groups showed a lower survival rate (50%), in the PLTx group were (P < .05). Further, the liver injury was more serious and the levels of serum biochemical parameters were higher. Compared with PHx groups, on days 3 and 5 postoperatively, the mitosis index and the expression of PCNA were lower among the PLTx groups. Compared with WLTx and sham operation groups, β2m-/Thy-1.1+, CD34+ cells in PB in PLTx groups and PHx were increased on day 1 postoperatively and decreased on the following days. Compared with PHx groups, β2m-/Thy-1.1+, CD34+ cells were higher in PLTx. The CD34-, c-kit-, and Thy-1.1-positive cells detected in portal tract areas peaked during 3 to 5 days postoperatively in PLTx. Few SRY+ cells were detected in PLTx liver grafts.β2m-/Thy-1.1+ and CD34+ stem cells mobilized after PLTx and PHx may be related to the reduced-size liver. Few HSC are involved in liver regeneration in PLTx.

Rats receiving either kidney or liver grafts were vaccinated with recombinant hepatitis B virus (HBV) vaccine either 1 or 10 weeks post-transplantation to explore the nonspecific immunosuppressive effect of transplantation surgery on antibody development. Response rate and geometric mean titer of the anti-HBs antibody were significantly lower in organ-transplanted animals undergoing early vaccination compared to unoperated control animals. Both parameters were affected when vaccination was performed early after kidney transplantation, but also in case of late vaccination in liver graft recipients. The nonspecific suppressive effect of transplantation surgery on the humoral immune response was related to the time point of vaccination after surgery and the extent of the surgical intervention and lasted longer than previously reported.

A prospective study on the effect of prenatal nutrition counseling on maternal nutrition status and infant birthweight was conducted at an antenatal care clinic by comparing a group of 80 women who attended nutrition counseling sessions with another group of 63 women who did not participate in nutrition counseling (controls). The daily intake of protein, calcium, iron, retinol, and riboflavin in the counseled group was higher than that in the control group. Moreover, the daily intake of nutrients of the counseled women met the recommended dietary allowance. Blood constituent determinations revealed that the levels of serum total protein, albumin, vitamin A, vitamin E, zinc, copper, magnesium, and hemoglobin in the blood of mothers and in umbilical blood at delivery were higher in the counseled group than in the control group (P less than 0.01). The women receiving counseling had fewer low-birthweight infants (1.52% vs 2.70%) and the incidence of maternal anemia was 39.1% against 55.6%, a significant difference (P less than 0.01).