[The use of CAD/CAM techniques in the repair of complex orbital fractures and the reposition of enophthalmos]

OBJECTIVE

To reconstruct the three-dimensional (3 D) imaging and computer-generated models of the complex orbital fractures, and to develop a Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM) system for orbital fracture repair.

METHODS

We carried out study on 12 patients with orbital fractures from August 2003 to March 2004 in the Ninth People's Hospital. Before the orbital fracture repair, helical computer tomography scanning was applied to acquire the 3 D imaging data of the patient's orbits. The 3 D imaging data were then transferred to a CAD/CAM interactive program for image processing, which then designed and produced a stereolithography model mathematically. Using the designed software, the repair of orbital fractures could be planned with the computer. At the same time, the orbital cubane was calculated. Then the operation was performed and the effect of the therapy was evaluated.

RESULTS

Using the CAD/CAM system of orbital fracture repair, the 3 D image of the orbit could be reconstructed, and the orbital cubane could be calculated accurately. The preoperative surgical plan was put into reality. After the orbital fracture repair, all cases received excellent appearance and function. This system had proved to run smoothly and accurately, and could easily be controlled.

CONCLUSIONS

The CAD/CAM system of the orbital fracture repair may be proved as one of the most useful clinical tools for orbital surgery.

A novel tool for B-cell tolerance research: characterization of mouse alloantibody development using a simple and reliable cellular ELISA technique

In animal-based transplantation research, the measurement of anti-donor antibodies in transplant recipients is limited by lack of an appropriate technique. We have developed a novel immunoassay capable of quantifying antibody bound to cell-surface major histo- compatability complex (MHC) and non-MHC antigens, using splenocytes from wild-type and MHC-deficient mice as antigen-bearing target cells. We utilized our "cellular ELISA" (CELISA) technique to study the development of tolerance versus immunity in the B-cell compartment in response to neonatal exposure to allogeneic fetal liver cells (FLC). This neonatal tolerance protocol typically induces permanent acceptance of donor-type and third-party cardiac allografts, but rejection of both donor-type and third-party skin grafts occurs. C3H/He (C3H; H-2(k)) mice were injected as neonates with BALB/c (BALB; H-2(d)) FLC and transplanted as adults with C57BL/6 (B6; H-2(b)) cardiac grafts. Despite long-term acceptance of third-party B6 cardiac grafts, serum contained increased anti-B6 IgG and IgM levels as measured by CELISA; IgM production was elevated by 2 weeks posttransplant and remained stable, while IgG production increased rapidly between 2 and 5 weeks posttransplant. In another experimental setting, CELISA assays were able to detect that neonatal injection of C3H mice with FLC from wild-type B6 mice or from MHC class II-deficient or class I/II-deficient (B6 background) mice (CI(+)CII(+), CI(+)CII(-), CI(-)CII(-), respectively) prevented sensitization to B6 antigens by subsequent skin transplants but did not induce graft acceptance, whereas FLC from MHC class I-deficient-only (CI(-)CII(+)) did not prevent B6 sensitization. The CELISA technique is a simple and sensitive means for quantifying alloantibodies in mice and will assist in further delineating the role of the B-cell compartment in neonatally induced cardiac allograft acceptance.

[Experimental study of tissue engineered bone loaded with osteointergrated dental implants]

OBJECTIVE

To investigate osteogenesis and integration of osteointergrated dental implants with marrow stromal osteoblast and cancellous bone matrix compound artificial bone (MCCAB) when embedded subcutaneously.

METHODS

Osteointergrated dental implants (3 mm in diameter) were inserted into cancellous bone matrix (CBM) columns (5 mm in diameter). Marrow stromal osteoblast (MSO) were cultured and expanded in the column and on the surface. The osteointergrated dental implants loaded MSO-Alginate-CBM compound was formatted. This compound was then implanted subcutaneously in nude mice, and the osteointergrated dental implants loaded Alginate-CBM compounds were implanted as control. The compound was in the mice for 4 to 8 weeks and then harvested and assessed by means of gross observation, X-ray examination, histologic observation and computerized histomorphometry for evaluation of bone formation.

RESULTS

The osteogenesis of the osteointergrated dental implants loaded MSO-Alginate-CBM compound was better than that of the the osteointergrated dental implants loaded Alginate-CBM compound. Both intramembranous and cartilaginous osteogenesis was seen but the former was predominant. A large amount of new bone formed around the implant and integrated well with the implant. In the control, only slight cartilage osteogenesis was seen and no integration was found.

CONCLUSIONS

The results suggest that the new bone forms in the scaffolds and on the surface of the implant, and integration between the implant and artificial bone also occurs when they are implanted in the nude mice.

Marrow-derived osteoblasts seeded into porous natural coral to prefabricate a vascularised bone graft in the shape of a human mandibular ramus: experimental study in rabbits

To find out if it was possible to prefabricate bone graft in the shape of a human mandibular ramus that possessed a pedicle that carried blood. The pore size of the natural coral was about 200 microm with a porosity of about 36%. The natural coral was made into the shape of a human mandibular ramus. Marrow-derived osteoblasts were seeded into porous natural coral scaffolds in a density of 2 x 10(8)/mL in 300 microL cell suspension. After two days of in vitro incubation, five cell-coral complexes were implanted into cell donor rabbits under the inferior epigastric blood vessels to prefabricate a vascularised bone graft of specific shape. Two months later the bone formation was observed by gross inspection and histological examination. Two months after operation, a well-vascularised bone graft in the shape of the initial coral scaffold and with a blood-carrying pedicle had been regenerated successfully. Osteogenesis followed the pattern of endochondral bone formation. New bone could be seen on the surface and in the pores of coral on histological examination. We have shown that it is possible to fabricate vascularised bone graft in a predetermined shape using tissue engineering. This kind of bone graft may have future clinical application.

Induction of human histo-blood group A antigen expression in mouse cells by gene therapy using lentiviral vectors harbouring human ABH-related glycosyltransferase genes

We recently discovered that ABO incompatibility, which evokes a rapid humoral immune response in adult heart transplantation, is not a barrier in infant heart transplantation, and that infant recipients of ABO-incompatible hearts develop specific B-cell tolerance to donor A/B antigens. An animal model of ABO-incompatible heart transplantation would allow detailed investigation of the mechanism(s) of acceptance of ABO-incompatible grafts, using experimental methods that would not be possible in humans. To determine the feasibility of such a model, the human alpha-1,2-fucosyltransferase (H-transferase; for H antigen expression) gene was cloned into a lentiviral vector, and the human alpha-1,3-N-acetylgalactosaminyltransferase (A-transferase; for A antigen expression) gene was cloned into a bicistronic lentiviral vector also containing the green fluorescent protein (GFP) gene; these replication-deficient vectors were denoted H-trs and A-GFP, respectively. Synthesis of the human histo-blood group A antigen in humans is dependent on expression of these two glycosyltransferases. HeLa cells, a human cell line known to be of blood group O origin, expressed cell surface A antigen as measured by cellular ELISA when transfected with A-GFP alone, and the level of A antigen expression was enhanced by transfection with H-trs in addition to A-GFP. Cell surface H antigen expression was observed on both mouse fibroblast and mouse endothelial cells only when infected with H-trs lentiviral particles. Expression of A antigen was dependent on infection with both H-trs and A-GFP lentiviral particles, approaching levels on human group A cells. These collective results indicate that expression of human histo-blood group A antigen at the cell surface can be induced in mouse cells by infection with H-trs and A-GFP, and that such A antigen expression is dependent on H-trs expression.

[The long-term effects of rhBMP-2 and rhbFGF on alkaline phosphatase of bone mesenchymal stem cells]

PURPOSE

To evaluate the long-term effects of rhBMP-2 and rhbFGF on alkaline phosphatase(ALP) of rabbit bone mesenchymal stem cells by using them alone, associatedly and sequentially.

METHODS

Under cell culture technique, ALP kits were used to evaluate ALP level of bone mesenchymal stem cells so as to reflect differentiation of the cells on the 2nd, 5th, 7th, and 10th day by adding rhBMP-2 and rhbFGF on different ways.

RESULTS

Statistical analysis showed that rhBMP-2 could enhance while rhbFGF could inhibit the ALP level of rabbit bone mesenchymal stem cells significantly in long term, and also in a dose-dependent manner. The effects of using rhBMP-2 alone was similar to that of using the two growth factors associatedly, and they were significantly higher than that of using rhbFGF alone and using them sequentially.

CONCLUSION

Different growth factor has different long-term effect on differentiation of bone mesenchymal stem cells by adding them on different ways.

Injectable bone

Temperature-dependent polymerising polyethylene oxide hydrogel was used as a vehicle to deliver bone marrow mesenchymal cells by injection in six nude mice, four mice acting as controls, to study generation of new bone in the cell-hydrogel complex. Mesenchymal cells were harvested by in vitro cell culture, and cells were seeded into polyethylene oxide solution. The density of the suspension was adjusted to 5 x 10(7)ml(-1). The hydrogel was obtained by adjusting the temperature to over 6 degrees C. Aliquots of 0.5 ml of the cell-hydrogel complexes were injected subcutaneously into the backs of the six experimental mice, and 0.5 ml of hydrogel alone was injected into the four controls. Generation of new bone was studied by gross inspection, radiographs, and histological examination. Two months after injection hard nodes had formed subcutaneously in all six mice, whereas in the control group the hydrogel had been absorbed completely and only soft tissue was present at the site of injection. A shadow could be seen on the radiographs of all cell-seeded mice. On histological examination of the nodes there was trabecular bone and some areas of neocartilage. This method of generating new bone might be of potential clinical use.

Treatment of interstitial peumopathy by fei tong oral liquid in the malignant tumor patients after radio- and/or chemotherapy

Fei Tong Kou Fu Ye ([symbol: see text]) Fei Tong Oral Liquid) was used to treat 30 cases of interstitial pneumopathy after radio- and/or chemotherapy. In comparison with the control group (15 cases) treated with hormones, the therapeutic effects in improving dyspnea, cough, respiratory rate, cyanosis, findings in X-films and CT examination, partial pressure of oxygen in artery, FVC and VC were found significantly better (P < 0.05). The total effective rate obtained was 83.33%.

Role of N-linked oligosaccharide flexibility in mannose phosphorylation of lysosomal enzyme cathepsin L

Mannose phosphorylation of N-linked oligosaccharides by UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase is a key step in the targeting of lysosomal enzymes in mammalian cells and tissues. The selectivity of this process is determined by lysine-based phosphorylation signals shared by lysosomal enzymes of diverse structure and function. By introducing new glycosylation sites at several locations on the surface of mouse procathepsin L and modeling oligosaccharide conformations for sites that are phosphorylated, it was shown that the inherent flexibility of N-linked oligosaccharides can account for the specificity of the transferase for oligosaccharides at different locations on the protein. By using this approach, the physical relationship between the lysine-based signal and the site of phosphorylation of mannose residues was determined. The analysis also revealed the existence of additional independent lysine-based phosphorylation signals on procathepsin L, which account for the low level of phosphorylation observed when the primary Lys-54/Lys-99 signal is ablated. Mutagenesis of residues that surround Lys-54 and Lys-99 and demonstration of mannose phosphorylation of a glycosylated derivative of green fluorescent protein provide strong evidence that the cathepsin L phosphorylation signal is a simple structure composed of as few as two well placed lysine residues.

Bone graft in the shape of human mandibular condyle reconstruction via seeding marrow-derived osteoblasts into porous coral in a nude mice model

PURPOSE

The purpose of this study was to develop a tissue-engineered bone graft model in the shape of a human mandibular condyle.

MATERIALS AND METHODS

Natural coral with a pore size of 150 to 220 microm and porosity of about 36% was molded into the shape of a human mandibular condyle. Culture-expanded rabbit marrow mesenchymal stem cells were induced by recombinant human bone morphogenetic protein-2 (rhBMP2) to improve osteoblastic phenotype. Then marrow-derived osteoblasts were seeded into natural coral at a density of 2 x 10(8)/mL and incubated in vitro for 3 days before implantation. The cell-coral complexes were implanted subcutaneously into the backs of nude mice and incubated in vivo for 2 months before harvesting. Implantation of coral alone acted as control. The specimens were processed for gross inspection, radiographic examination, and histologic and scanning electronic microscopic observation.

RESULTS

The results showed that new bone grafts in the shape of a human mandibular condyle were successfully developed 2 months after implantation and maintained the initial shape of the natural coral scaffold. New bone could be observed histologically on the surface and in the pores of natural coral in all specimens in the cell-seeding group (6 of 6), whereas in the control group there was no evidence of osteogenesis process (0 of 4).

CONCLUSION

This study suggests the feasibility of using porous coral as scaffold material transplanted with marrow-derived osteoblasts to restore bone graft in the shape of human mandibular condyle and shows the potential of using this method for the reconstruction of bone defects.

[Experimental studies on cranial defect repair with marrow stromal osteoblast-cancellous bone matrix compound artificial bone]

OBJECTIVE

To investigate the feasibility of using marrow stromal osteoblast-cancellous bone matrix compound artificial bone (MCCAB) as tissue-engineered bone, the osteogenesis of MCCAB in the cranial defect was observed in the experiment.

METHODS

The in vitro cultivated and induced marrow stromal cells of adult New Zealand rabbits were seeded into the alginate-cancellous bone matrix to form MCCAB. The MCCAB was then implanted into the cranial defect for 4 to 8 weeks. The cancellous bone matrix (CBM) alone or the marrow stromal osteoblasts (MSOs) alone was implanted as the control. The effectiveness of bone formation was assessed by histological and roentgenographic analysis.

RESULTS

The osteogenesis of MCCAB was better than CBM or MSOs and superior to the blank group.

CONCLUSION

MCCAB can effectively repair cranial defect. It could be used clinically to restore large bone defects.

[Combined surgery for cardiovascular disease and general thoracic lesions]

Surgical management of patients with concomitant critical cardiovascular disease and resectable general thoracic lesions is controversial. During a 16-year period (1985 to 2001), 15 patients underwent combined cardiovascular and general thoracic operations, of the 2,459 patients who underwent a cardiovascular operation requiring cardiopulmonary bypass at our institution. Patients had cardiovascular symptoms only and the general thoracic lesions were incidentally found by preoperative chest roentgenograms and/or computed tomography. Because of the cardiovascular disease, a pathological diagnosis was precluded before surgery. All except one descending thoracic aortic operation underwent concurrent pulmonary resection after neutralization of protamine following cardiovascular surgery requiring extracorporeal circulation. Lung pathology consisted of pulmonary bullae (n = 7), primary lung cancer (n = 4), benign lung tumor (n = 2), metastatic lung cancer (n = 1), and thymic cyst (n = 1). The pulmonary operations include bullectomy (n = 7), wedge resection (n = 6), lobectomy (n = 3), and removal of a thymic cyst (n = 1) including 2 staged procedures. The final diagnoses in 4 lung cancer cases were T1. N0M0, stage IA (n = 3) and T2N2M0, stage IIIA (n = 1). All malignancies including metastatic lung cancer, were able to be completely resected. The mean intraoperative bleeding volume for the cases was 997 +/- 221 ml, while mean duration of surgery was 382 +/- 31 minutes. Except for 2 cases required long term ventilatory support, the mean durations of tracheal intubation and ICU stay were 2.2 +/- 0.2 and 3.8 +/- 1.0 days respectively. Except for 1 surgical death, mean survival duration and 5-year survival rate were 59.7 +/- 12.5 (5-177) months and 66.3% respectively. These findings suggest that combined pulmonary resection with cardiovascular surgery is safe and offers a favorable prognosis to a selected group of patients.

[Experimental study on subcutaneous bone formation by marrow stromal osteoblast-cancellous bone matrix compound artificial bone]

OBJECTIVE

To investigate the feasibility of using marrow stromal osteoblast (MSO) as bone derived cell and using cancellous bone matrix (CBM) as scaffold for bone tissue engineering, the subcutaneous osteogenesis of MSO-CBM compound artificial bone (MCCAB) was observed in the experiment.

METHODS

The marrow stromal cells of adult New Zealand rabbits cultivated and induced in vitro were used to form MCCAB by mixing, seeding and solidifying methods assisted by alginate. The MCCABs were auto-transplanted subcutaneously into the rabbits for 4 to 8 weeks. The alginate-cancellous bone matrix composites or the cancellous bone matrix alone were implanted as control. The effectiveness of bone formation was assessed by means of roentgenography, histology and computerized histomorphometry.

RESULTS

The osteogenesis of MCCABs was better than that of the alginate-cancellous bone matrix composites and of the cancellous bone matrixes. In the MCCABs, both intramembranous and cartilaginous osteogeneses were seen but the former was obvious. In the control, only slight cartilaginous osteogeneses were seen.

CONCLUSIONS

The osteogeneses of the MCCABs constructed by using tissue engineering method were obvious when transplanted subcutaneously. The MSO and CBM can be used as good bone-derived cell and scaffold material respectively for tissue-engineered bone construction.

Multiple lysosomal trafficking phenotypes in metastatic mouse mammary tumor cell lines

Although altered synthesis and trafficking of lysosomal proteins and their receptors are associated with a wide range of human and rodent malignancies, the basis for their involvement remains obscure. Here we describe findings on a set of mouse mammary tumor cell lines that we are using as a model to study the role of these proteins in oncogenesis and tumor progression. Three distinct proteinase-secreting phenotypes were identified among the metastatic cell lines of the set. Two phenotypes displayed a high level of secretion of cathepsin L and the third was characterized by elevated secretion of matrix metalloproteinase 9 (MMP-9). The two cathepsin L-secreting phenotypes were distinct in that they displayed differences in cathepsin trafficking, expression of mannose 6-phosphate/insulin-like growth factor receptor and expression of proliferin, a mannose-phosphorylated angiogenic factor. Although cells representing all three phenotypes are capable of dissemination to distant organs when implanted into mouse mammary glands, only cells with the MMP-9 phenotype were found to be capable of direct intravasation. These findings indicate that multiple proteinase-secreting phenotypes can arise from the same tumor and suggest that cathepsin L and other lysosomal proteins may play a role in dissemination of tumor cells via the lymphatic system.

[The cytotoxic effects of the adriamycin magnetic albumin microspheres combined with external magnetic fields on the malignant tumor cells]

This study sought to assess the inhibitory effects of the adriamycin magnetic albumin microspheres (ADM-MAMs) on Walker-256 malignant tumor cells in vitro induced by the permanent magnetic fields. The cultured Walker-256 cells were divided into three groups; the group of ADM-MAMs combined with magnetic fields, the group of AMD-MAMs without magnetic fields, and ADM group. The growth states of the cells were observed and photographed under the inverted microscope. The inhibitory rates(IR) were assayed by the modified MTT colorimetric method. The results showed that the IR of the ADM-MAMs group were similar to those of the ADM group (P > 0.05), but the group of ADM-MAMs combined with magnetic fields had obviously higher IR and significant changes of the cells' shapes. These findings indicate that the anticancer effect of ADM-MAMs on malignant tumor cells is similar to that of ADM, and such effect can be increased by the combined use of ADM-MAMs and external magnetic fields.

A study of injectable tissue-engineered autologous cartilage

OBJECTIVE

To test the effectiveness of the new techniques of tissue-engineered cartilage.

METHODS

Chondrocytes were harvested through type II collagenase digestion from the auricle of New Zealand rabbits. The cells were mixed with alginate to generate chondrocytes/alginate composites with final cellular density of 50 x 10(6) per mL. Calcium chloride was used as the cross-linking agent to gel the aqueous alginate solution. The chondrocytes/alginate composites were injected into the dorsal subcutaneous tissue of New Zealand rabbits through autologous cells grafts. The specimens were observed during cartilage formation at 4, 8, and 12 weeks after injection.

RESULTS

Prior to harvesting, chondrocytes/alginate composites were easily visualized under the dorsal skin of animals. The appearance of experimental specimens was similar to that of native cartilage in gross morphology. Using a standard hematoxylin and eosin stain, the histologic features of all experimental specimens demonstrated new cartilage formation. With a Masson's trichrome and safranin O stain, the presence of collagen and glycosaminoglycan (GAG) was observed at 8 and 12 weeks.

CONCLUSION

This study demonstrated that polymerization of alginate hydrogel can be controlled to allow injection of chondrocytes that produce new autologous cartilage at subcutaneous dorsal site of rabbits. Injectable tissue-engineered autologous cartilage is promising for potential use in oral and maxillofacial surgery.

Polysialyltransferase-1 autopolysialylation is not requisite for polysialylation of neural cell adhesion molecule

Polysialyltransferase-1 (PST; ST8Sia IV) is one of the alpha2, 8-polysialyltransferases responsible for the polysialylation of the neural cell adhesion molecule (NCAM). The presence of polysialic acid on NCAM has been shown to modulate cell-cell and cell-matrix interactions. We previously reported that the PST enzyme itself is modified by alpha2,8-linked polysialic acid chains in vivo. To understand the role of autopolysialylation in PST enzymatic activity, we employed a mutagenesis approach. We found that PST is modified by five Asn-linked oligosaccharides and that the vast majority of the polysialic acid is found on the oligosaccharide modifying Asn-74. In addition, the presence of the oligosaccharide on Asn-119 appeared to be required for folding of PST into an active enzyme. Co-expression of the PST Asn mutants with NCAM demonstrated that autopolysialylation is not required for PST polysialyltransferase activity. Notably, catalytically active, non-autopolysialylated PST does not polysialylate any endogenous COS-1 cell proteins, highlighting the protein specificity of polysialylation. Immunoblot analyses of NCAM polysialylation by polysialylated and non-autopolysialylated PST suggests that the NCAM is polysialylated to a higher degree by autopolysialylated PST. We conclude that autopolysialylation of PST is not required for, but does enhance, NCAM polysialylation.

[Investigation on Schistosoma japonicum infection in rodents in Yunnan Province]

OBJECTIVE

To investigate the role of rodents in the transmission of schistosomiasis in endemic areas in Yunnan Province.

METHODS

Kato-Katz method was used to study the infection rate of rodents, humans and domestic animals.

RESULTS

The infection rate was 0.9% (32/3,411) for rodents, 15.6% (461/2,964) for humans, and 9.6% (239/2,482), for domestic animals. The EPG(mean) was 5.8 for rodents, 1.8 for humans, 0.1 for cattle, 0.1 for horses and 0.02 for pigs.

CONCLUSION

The rodents played a minor role in the transmission of schistosomiasis in the plateau area of Yunnan province.

The relationship between apoptosis and the expression of proliferating cell nuclear antigen and the clinical stages in gastric carcinoma

The relationship between the apoptosis and the expression of proliferating cell nuclear antigen (PCNA) and the clinical stages in gastric cancers was studied. By using terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) technique and PCNA immunohistochemical staining, the apoptosis and the expression of PCNA in tissue of gastric carcinoma were assayed in situ, the index of apoptosis (AI), index of PCNA (PI) and the rate of AI/PI were calculated. AI and PI in gastric cancer tissues were (6.5 +/- 3.7)% and (49.8 +/- 15.9)% respectively, and the rate of AI/PI was 0.13 +/- 0.05, which were obviously different from those of normal gastric mucosa in paragastric cancer (P < 0.01). With the advanced TNM stages of gastric carcinoma, the AI was decreased, PI was increased and the rate of AI/PI decreased in gastric carcinoma. There was significant difference in them between the gastric cancer tissues and normal gastric mucosa in pericarcinoma in TNM stage II to IV (P < 0.05). It was suggested that the decreased apoptotic cells and the increased proliferating cells were obviously related to the tumor genesis and tumor progression in gastric carcinoma. The AI, PI and the rate of AI/PI would become the prognostic factors in advanced gastric carcinoma.

Toxicity of magnetic albumin microspheres bearing adriamycin

Magnetic albumin microspheres bearing adriamycin (ADM-MAM) is a novel chemotherapeutic compound with site-specific drug delivery characteristics. The acute and subacute toxic tests of the compound, local irritating test and anaphylactic test were performed on mice and guinea pigs. The results showed there was no macroscopically and microscopically direct cytotoxic injuries of the compound to the animal organs or to the cells. The LD50 value of the compound was higher than that of the single used adriamycin, indicating that the compound was less toxic than the single adriamycin and quite safe in its therapeutic dosage. Furthermore, there was also no side effects or toxic reactions to be observed on clinical patients with advanced carcinoma or gastric cancer.

In vivo oxidation-reduction kinetics of OxyR, the transcriptional activator for an oxidative stress-inducible regulon in Escherichia coli

The OxyR protein is a transcriptional activator for a subset of peroxide stress-inducible genes, most of which are involved in defense systems against oxidative stress. Recently, it was demonstrated that purified OxyR has one intramolecular disulfide bond, which led to the proposal that the reversible disulfide bond formation regulates the activity of OxyR as a transcription factor in response to peroxide stress. In this study, I demonstrated by SDS-PAGE under non-reducing conditions that an intramolecular disulfide bond is formed in OxyR upon exposure of the cells to hydrogen peroxide in vivo. Experiments using strains expressing mutant OxyR proteins with Cys to Ser single amino acids substitutions confirmed that the disulfide bond is formed between the Cys-199 and -208. Kinetic analyses indicated that the formation of the disulfide bond is rapid and transient, oxidized within 30 s and re-reduced within 5 min after the addition of hydrogen peroxide in the wild-type strain. These results provide evidence for the regulatory role of the reversible oxidation of dithiol to disulfide in sensing peroxide stress in vivo and signal transduction to the transcription apparatus by OxyR.

[Analysis and prevention of reoperation on congenital choledochal cyst]

OBJECTIVE

To investigate the reasons and prevention of reoperation on congenital choledochal cyst (CCC).

METHODS

The sex, age, cyst type, timing and method of operation were analyzed 22 reoperated (CCC) patients who underwent reoperation.

RESULTS

The reoperation rate was 24.4% (22/90). The gender age and cyst type were not related to reoperation rate (P > 0.05). Reoperation rate was correlated with the timing the modality and the manoeuvre of the surgery. The previous emergent surgery incurred higher reoperation rate than that of selective operation (P < 0.01). The reoperation rate was 88.9% in patients previously undergoing CCC extracorporeal drainage, it was 52.4% in group of internal drainage and 5.0% in group previously undergoing CCC resection (P < 0.01).

CONCLUSIONS

Congenital choledochal cyst should be treated by surgery in its early stage. Pradent policy should be adopted on the use of PTC and ERCP. Outer drainage was used as the first-aid measure; internal drainage should be abandoned; resection of the cyst with Roux-Y hepaticojejunostomy should be the therapy of choice.

[Experiment and clinical application of targeting treatment with adriamycin magnetic albumin microspheres in human gastric carcinoma]

OBJECTIVE

To study the pharmacokinetics in experimental animals and observe the concurrent anticancer effects in human advanced gastric cancer as an adjuvant chemotherapy, when adriamycin magnetic albumin microspheres (ADM-MAM) were combined with external static magnetic fields.

METHODS

The drug concentration of targeting tissues in the animals and the stability of ADM-MAM in human gastric juices were determined. Clinical and histopathological changes were observed in 55 cases of advanced gastric carcinomas after targeting treatment.

RESULTS

The peak concentrations of the targeting tissue were highest after ADM-MAMs were administered for 2 hours and remained at the high level for a long time. ADM-MAM maintained its stability in human gastric juices. Targeting treatment improved the patients' symptoms, raised the rated of tumor resection, prolonged patients' lifetime, and enhanced histopathological effects (P < 0.01).

CONCLUSIONS

The administration of ADM-MAM combined with the external static magnetic fields is effective for targeting location and is of clinical value as a preoperative adjuvant chemotherapy for human advanced gastric carcinoma.

Lysine-based structure responsible for selective mannose phosphorylation of cathepsin D and cathepsin L defines a common structural motif for lysosomal enzyme targeting

Previous studies have shown that lysine residues on the surface of cathepsins and other lysosomal proteins are a shared component of the recognition structure involved in mannose phosphorylation. In this study, the involvement of specific lysine residues in mannose phosphorylation of cathepsin D was explored by site-directed mutagenesis. Mutation of two lysine residues in the mature portion of the protein, Lys-203 and Lys-293, cooperated to inhibit mannose phosphorylation by 70%. Other positively charged residues could not substitute for lysine at these positions, and comparison of thermal denaturation curves for the wild type and mutant proteins indicated that the inhibition could not be explained by alterations in protein folding. Structural comparisons of the two lysine residues with those required for phosphorylation of cathepsin L, using models generated from recently acquired crystal structures, revealed several relevant similarities. On both molecules, the lysine residues were positioned approximately 34 A apart (34.06 A for cathepsin D and 33.80 A for cathepsin L). When the lysine pairs were superimposed, N-linked glycosylation sites on the two proteins were found to be oriented so that oligosaccharides extending out from the sites could share a common region of space. Further similarities in the local environments of the critical lysines were also observed. These results provide details for a common lysosomal targeting structure based on a specific arrangement of lysine residues with respect to each other and to glycosylation sites on the surface of lysosomal proteins.

[Living related liver transplantation: a case report]

OBJECTIVE

To study a case of living related liver transplantation.

METHOD

The patient was a 10-year-old girl who suffered from congenital diffuse intrahepatic cholangiectasis, recurrent cholangitis and hepatocirrhosis. The donor was the patient's father aged 40. The left lateral lobe of donor's liver was cut and grafted to the patient. Intensive care and treatment as well as follow-up were given after operation.

RESULT

For the donor, the operation lasted 400 min, with 410 ml bleeding and 300 g liver removed. The recovery was satisfactory. For the recipient, the operation lasted 652 min, with 1665 ml bleeding, 80 min non-liver stage, 0 min graft hot ischemic stage, and 137 min cold ischemic stage. Immunosuppressive therapy was given using cyclosporin A, azathioprine and adrenocortical hormones. There was an acute rejection 11 days after operation, which was controlled using hormone impulsive therapy. The patient has been surviving 7 months with normal liver function.

CONCLUSION

The living related liver transplantation is feasible under modern surgical conditions. It is demonstrated that perfect postoperative management is the key for the successful liver transplantation.

[Determination of the soluble non-starch polysaccharides in rice and wheat bran by gas chromatography]

Cereal polysaccharides can be broadly classified into two distinct and chemically well-defined types. They are the storage polysaccharides (alpha-glucan) and the structural polysaccharides starch (beta-glucan) which are usually called non-starch polysaccharides (NSP). The determination of soluble non-starch polysaccharides in rice and wheat bran by gas chromatography has been developed. The free sugars in the sample were extracted with 80% ethanol. The residue was hydrolyzed in an acetic acid buffer solution (pH 5.0) in the presence of amylase and amyloglucosidase to remove starch. The soluble NSP obtained was further hydrolyzed in the acidic condition to produce the corresponding monosaccharides which were derivatized to form alditol acetates for GC analysis with allose as the internal standard. The GC conditions were OV-1701 column (25 m x 0.3 mm) with temperature program from 195 degrees C to 225 degrees C and FID.

oxyR-dependent induction of Escherichia coli grx gene expression by peroxide stress

The Escherichia coli OxyR protein is a transcriptional activator for a number of genes induced in response to low concentrations of hydrogen peroxide. To identify additional OxyR-regulated genes, I cloned a DNA fragment that shows promoter activity regulated by OxyR by direct selection of OxyR-binding DNA fragments. Analyses of the cloned fragment indicate that the grx gene, encoding glutaredoxin 1, is inducible by hydrogen peroxide in an oxyR-dependent fashion.

Expression in Escherichia coli and purification of human thrombopoietin

Human thrombopoietin (TPO) has been successfully overexpressed in Escherichia coli, with an expression level of about 12% of total cellular protein. The full-length TPO gene was subcloned into the prokaryotic expression vector pKK233-2 under the control of the inducible tac promoter. The recombinant protein was produced mainly in the form of inclusion body. By efficient renaturation and one-step purification, the recombinant protein was purified to homogeneity. The specific activity and yield of recombinant TPO can reach 2 x 10(4) units/mg and 2 mg/g of wet E. coli cells respectively.

[Diagnosis and treatment of congenital choledochal cyst]

From January 1980 to June 1996, 82 patients with congenital choledochal cysts were treated and 76 of them were operated on B-ultrasonic diagnosis was made with a correct diaginostic rate of 93.9%. The total effective rate was was 78.4% after follow-up for 84 months. Resection of the cyst with Roux-Y hepaticojejunostomy was successful in 96.2% of the patients. Outer drainage was used as the first-aid measure. Cystoduodenostomy and cystojejunostoy which may lead to complications should be abandoned.

Mutagenicity of high fat diets in the colon and small intestine of transgenic mice

Dietary fat has been implicated as a cause of colon cancer by epidemiological studies. Unfortunately, these studies are compatible with high fat as either initiator or promoter. Since initiators are normally mutagenic, we have tested the mutagenicity of high fat diets in the intestinal epithelium at two loci. The Dlb-1 assay, used in the small intestine, detects a wide spectrum of mutations. The lacI assay (Big Blue Mouse assay) is not as sensitive to some types of mutation as is Dlb-1 but was used in the colonic epithelium. Mice suitable for both assays were fed isocaloric high fat diets and subsequently assayed for somatic mutation. The diets consisted of: (i) a mixture of beef tallow, butter and lard totalling to 31% w/w of the diet (AIN-76A) up to 17 weeks; and (ii) corn oil, beef tallow, lard or butter individually, at 31% w/w of the diet for 5 and 9 weeks. These diets provided 50% of the calories from fat. The weights of the experimental and control mice were similar throughout the experiment. No significant increases in mutant frequencies were observed on any high fat diet compared to controls, so we conclude that uncooked fats are not mutagenic and are not initiators of carcinogenesis in the intestinal epithelium.

Mapping of the OxyR protein contact site in the C-terminal region of RNA polymerase alpha subunit

The Escherichia coli OxyR protein requires the C-terminal contact site I region of the RNA polymerase alpha subunit for cooperative interaction with and transcription activation at OxyR-dependent promoters, suggesting direct protein-protein contact between OxyR and the C-terminal region of the alpha subunit. To determine the precise location of the OxyR protein contact site(s) in this region, we carried out mutational analysis of the 3' half of E. coli rpoA, the gene encoding the alpha subunit of RNA polymerase. We isolated a number of rpoA mutants defective in oxyR-dependent transcription activation at the E. coli katG promoter. Nucleotide sequence analysis of the rpoA gene from these mutants revealed that the mutations showing clear phenotypes are all clustered at two narrow regions (amino acid residues 265 to 269 and 293 to 300) within the C terminus of the alpha subunit. Reconstituted RNA polymerases containing the mutant alpha subunits were unable to respond to transcription activation in vitro at the katG, ahpC, and oxyX promoters by OxyR. These results suggest that these two regions comprise the contact surfaces on the alpha subunit for OxyR.

The transmission rate of the lacI transgene from the Big Blue mouse

Since transgenic mice are being used to analyze somatic and germinal mutation rates in vivo, it is of interest to know to what extent these mice are normal or abnormal in any way. During experiments designed to compare the mutational response of the transgene and an endogenous gene, Big Blue mice hemizygous for the transgene were bred to create a hybrid mouse in which the comparisons could be made. The fraction of these mice that inherited the transgene was 37% rather than the Mendelian expectation of 50%.

Lysine-based structure in the proregion of procathepsin L is the recognition site for mannose phosphorylation

The recognition of lysosomal enzymes by UDP-GlcNAc: lysosomal-enzyme GlcNAc-1-phosphotransferase (phosphotransferase) is mediated by a protein structure on lysosomal enzymes. It has been previously demonstrated that lysine residues are required for phosphorylation of procathepsin L and are a common feature of the site on many lysosomal proteins. In this work, the procathepsin L recognition structure was further defined by identification of the region of the protein containing the structure and the critical lysine residues involved. Removal of the cathepsin L propeptide by low pH-induced autocatalytic processing abolished phosphorylation. The addition of either the purified propeptide or a glutathione S-transferase-propeptide fusion protein to the processed protein restored phosphorylation. Mutagenesis of individual lysine residues demonstrated that two propeptide lysine residues (Lys-54 and Lys-99) were required for efficient phosphorylation of procathepsin L. By comparison of the phosphorylation rates of procathepsin L, lysine-modified procathepsin L, and the procathepsin L oligosaccharide, lysine residues were shown to account for most, if not all, of the protein-dependent interaction. On this basis, it is concluded that the proregion lysine residues are the major elements of the procathepsin L recognition site. In addition, lysine residues in cathepsin D were shown to be as important for phosphorylation as those in procathepsin L, supporting a general model of the recognition site as a specific three-dimensional arrangement of lysine residues exposed on the surface of lysosomal proteins.

The proregion of cathepsin L is required for proper folding, stability, and ER exit

To investigate the role of the proregion in the biosynthesis and trafficking of mouse cathepsin L, cathepsin L cDNAs encoding proteins with altered proregions were constructed and their expression in COS cells was examined. As in transformed cells, normal mouse cathepsin L was secreted by COS cells. In contrast, two altered proregion cathepsin L proteins, one in which the proregion was deleted and a second in which the proregion was replaced with that of a homologous protein (aleurain), were retained within the cell and degraded over a period of 2-6 h. Immunofluorescence localization and the lack of effect of NH4Cl and brefeldin A on the turnover of the altered cathepsin L proteins indicated that their degradation occurred in the endoplasmic reticulum (ER). By using brefeldin A to induce colocalization of the UDPGlcNAc: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase with the cathepsin L proteins in the ER, it was shown that the altered proteins were not susceptible to mannose phosphorylation as they exist in the ER. Trypsin sensitivity assays indicated that altered proregion proteins synthesized in COS cells or in vitro are misfolded. Taken together, these results indicate that the proregion plays an essential role in proper folding of cathepsin L. ER retention, decreased stability, and lack of mannose phosphorylation of the altered proteins are most likely secondary effects resulting from improper folding.

Involvement of the RNA polymerase alpha subunit C-terminal region in co-operative interaction and transcriptional activation with OxyR protein

The role of the alpha subunit of Escherichia coli RNA polymerase in transcription activation by the OxyR protein was investigated using in-vitro-reconstituted RNA polymerase containing alpha subunits carrying C-terminal truncations or an amino acid substitution. Mutant RNA polymerases failed to respond to transcription activation of the E. coli OxyR-dependent promoters. DNase I footprinting analysis indicates that the OxyR protein exerts a co-operative effect on the binding of wild-type RNA polymerase, but not the mutant RNA polymerases, to the katG promoter. Together, these results suggest that direct protein-protein contact between the OxyR protein and the C-terminal contact site I region of the RNA polymerase alpha subunit plays an essential role in transcription activation at the OxyR-dependent promoters.

[IgA nephropathy in Chinese and Australian patients: a comparison between clinical and pathological features]

The clinical and pathological data were compared between 88 Chinese and 88 Australian patients with IgA nephropathy, whose age, sex and course of disease identified by renal biopsy were matched. Statistical differences showed: More Chinese patients had edema and loin pain, while more Australian patients had hypertension, glomerular sclerosis and arterial and/or arteriolar abnormalities; impairment of renal function correlated with crescent body formation and loin pain with severe hematuria were only found in Chinese patients, While correlations between severe hematuria and histological changes, hypertension and glomerular sclerosis, impaired renal function and glomerular sclerosis were only seen in Australian patients. Differences between the two groups in symptoms, histological changes and clinico-pathological correlations suggest that IgA nephropathy is a heterogeneous disease, it may result from more than one factor.

Purification and characterization of the Escherichia coli OxyR protein, the positive regulator for a hydrogen peroxide-inducible regulon

The Escherichia coli oxyR gene is required for the induction of a regulon that is inducible by hydrogen peroxide and confers resistance to oxidative stresses. We constructed a plasmid system that greatly overproduced OxyR protein and purified the protein. OxyR protein specifically bound to the upstream regulatory regions of the oxyR and katG genes as demonstrated by the gel-retardation assay and the DNase I footprinting experiment, and activated the transcription initiation of the katG gene in vitro. Using a plasmid carrying an oxyR'-'lacZ fusion gene, we studied the regulation of oxyR expression in vivo. The expression of oxyR was not induced by the treatment with a low concentration of hydrogen peroxide which induces the genes in the oxyR regulon. The expression of the oxyR'-'lacZ gene was higher in an oxyR-deletion strain than in the oxyR+ strain, and was repressed by overexpressing the OxyR protein. These results suggest that OxyR protein functions as a repressor for oxyR, in addition to its known function as a transcriptional activator for the genes in the oxyR regulon.

Expression of complement 3 receptors (CR1 and CR3) on neutrophils and erythrocytes in patients with IgA nephropathy

Expression of C3 receptors (CR1 and CR3) on neutrophils (PMN) was measured in 26 patients with IgA nephropathy (IgA N), 17 normal persons, and 8 patients with non-IgA glomerulonephritis (non-IgA GN) by fluorescence activated cell sorting after labeling with monoclonal antibodies. Mean channel fluorescence for both CR1 and CR3 on PMN was significantly higher in IgA N patients than in either control group (p less than 0.01). (CR1 mean +/- SD 42.5 +/- 10.4 in IgA N, 31.7 +/- 11.5 in normal controls, 27.8 +/- 9.0 in non-IgA GN; CR3 94.0 +/- 16.5, 75.0 +/- 16.6 and 76.7 +/- 15.6, respectively.) No differences were found between the two control groups or between IgA N patients with normal and impaired renal function. These results imply that PMN are activated in IgA N patients. The expression of CR1 and CR3 of PMN may be upregulated by immune complexes (ICs), enhancing both phagocytosis of C3b- or iC3b-coated particles, and absorptive pinocytosis of soluble ICs containing C3b or iC3b. Erythrocyte CR1 and CR3 expression was measured by ELISA and found to be slightly but significantly lower in IgA N patients than in the other 2 groups (CR1 85.3 +/- 28.4 in IgA N, 113.1 +/- 28.8 in normal controls, 109.4 +/- 28.2 in non-IgA GN, p less than 0.02; CR3 80.9 +/- 20.0, 100.4 +/- 19.9, 101.2 +/- 24.9, respectively, p less than 0.05).

Molecular cloning and nucleotide sequencing of oxyR, the positive regulatory gene of a regulon for an adaptive response to oxidative stress in Escherichia coli: homologies between OxyR protein and a family of bacterial activator proteins

Treatment of Escherichia coli and Salmonella typhimurium cells with a low dose of hydrogen peroxide induces expression of a large number of genes, and confers resistance to oxidative stresses. The oxyR gene encodes a positive regulatory protein for a subset of these genes involved in the defense against oxidative damage. We cloned a DNA fragment that contains the E. coli oxyR region on a plasmid vector, and analyzed the nucleotide sequence of the gene. The amino acid sequence of OxyR protein, deduced from the nucleotide sequence, shows a high degree of homology to the sequences of a number of bacterial activator proteins including LysR, CysB, IlvY, MetR and NodD. The product of the oxyR gene identified by the maxicell procedure was a 34 kDa protein, which agrees with the size predicted from the nucleotide sequence of the gene.