[The study on hereditary polymorphism of thiopurine S-methyltransferasein Chinese Han population of Shanghai area]

OBJECTIVE

To gain an insight into the hereditary polymorphism of thiopurine methyltransferase(TPMT) activity in Chinese Han population of Shanghai.

METHODS

The present authors measured the erythrocyte TPMT activity in 320 healthy Chinese volunteers and 51 children with acute lymphoblastic leukemia(ALL) by means of radiochemical assay.

RESULTS

The TPMT activity levels ranged from 4. 32 to 32.33 U/ml pRBCs, with a mean value of (16.64+/-4.50) U/ml pRBCs, male (16.78+/-4.96) U/ml pRBCs, female (16.52+/-4.44) U/ml pRBCs. Eight point one percent of the sample had low activity. The TPMT activity levels for subjects who were <12 years, 13-18 years, 19-45 years and >45 years old were (16.52+/-4.31) U/ml pRBCs, (16. 71+/-4.24) U/ml pRBCs, (16.28+/-5.21) U/ml pRBCs and (17.11+/-3.98) U/ml pRBCs, respectively; the TPMT activity levels for healthy volunteers and patients with ALL were (16.65+/-4.72) U/ml pRBCs and (16.52+/-4.47) U/ml pRBCs, respectively.

CONCLUSION

There were no differences of TPMT activity in gender, age, and between healthy volunteers and patients with ALL.

[ATP synthesis by free yeast catalysis coupling hollow fiber ultrafiltration separation]

A novel process for the ATP production employing free yeast catalysis and coupling a hollow fiber module ultrafiltration separation was studied. The experimental results of biocatalyst half-life and operating stability for ultrafiltration showed that the enzymes released from free yeast cell could be cut-off efficiently from the product output stream by hollow fiber membrane. The intercepted percentage of ADH and HK reached more than 95% during the steady running. The efficiency of enzymes utilized was 2.0-2.5 fold as much as that of batch reaction. And the time of yeast cells used repeatedly for ATP synthesis reached 2.5-3.0 batches. Under 0.1 MPa, the ultrafiltrating speed of hollow fiber membrane could keep on a stabilizing value for 11 batches continuously. The continuous operation mode of ATP synthesis simultaneous product ultrafiltration separation could be maintained in higher conversion rate for 5.0 h when the whole system fell in a pseudo-stat where the dilution rate was equal to 0.25 h-1.

Identification and characterization of estrogen receptor variants in prostate cancer cell lines

A sensitive semi-nested reverse transcriptase-polymerase chain reaction (RT-PCR) amplification was performed to evaluate estrogen receptor-alpha (ER-alpha) mRNA expression in prostate cancer cell lines. We demonstrated the presence of wild-type ER-alpha (wt ER-alpha) and five ER-alpha variants, designated ER-alphaA, B, C, D, and E. Unlike ER-alphaA and D, ER-alphaB, C, and E were not previously reported in normal or cancerous mammalian cells. DNA sequencing analysis of these ER-alpha variants revealed the genetic changes to be either in-frame or out-of-frame deletions. The expression of each ER-alpha variant differs significantly depending on the androgen responsiveness, tumorigenic and metastatic potentials of each prostate cancer cell line. The potential functional significance of ER-alpha variants was assessed in yeast two-hybrid and ERE promoter-reporter mammalian transcription assay systems. The results of these studies indicated that none of the ER-alpha variants can form homo- or heterodimers either with wt ER-alpha or among themselves in vivo, and that these ER-alpha variants have no demonstrable transcriptional or dominant-negative activity, as assessed in vitro.

[Effects of an extract of Ginkgo biloba on the blood flow of brains and back legs of dogs]

After injecting the injection of an extract of Ginkgo biloba, the cerebral blood flow of dogs wrer increased (P < 0.05-0.001). So were the back legs. And the cerebrovascular resistance was decreased (P < 0.05-0.001).

Scaffold precoating with human autologous extracellular matrix for improved cell attachment in cardiovascular tissue engineering

Cell attachment to a scaffold is a precondition for the development of bioengineered valves and vascular substitutes. This attachment is generally facilitated by the use of precoating factors, but some can cause toxic or immunologic side effects. Autologous extracellular matrix (ECM) is used as a precoating factor in our study. Ascending aortic tissue was cultured to obtain human myofibroblasts. Autologous ECM was extracted from the same aortic tissue. Poly(glycolic acid) (PGA) scaffolds were precoated with autologous ECM, human serum, or poly-L-lysine; the control group was pretreated with phosphate buffered saline (PBS). Myofibroblasts were seeded onto each scaffold, and the cell attachment was assayed and compared. Compared with the control group, precoating with human serum, poly-L-lysine, and ECM increased number of attached cells by 24%, 53%, and 48%, respectively. Differences between precoating groups were significant (p < 0.01), except for ECM versus poly-L-lysine. Scanning electron microscopy also demonstrated the high degree of cell attachment to the PGA fibers on scaffolds precoated with ECM and poly-L-lysine. Precoating polymeric scaffold with autologous human extracellular matrix is a very effective method of improving cell attachment in cardiovascular tissue engineering without the potential risk of immunologic reactions.

Constituents of red yeast rice, a traditional Chinese food and medicine

Detailed analyses were undertaken of the natural constituents of red yeast rice, a traditional Chinese medicine and food known for centuries to improve blood circulation. Preparation of red yeast rice following ancient methods by fermenting the fungal strain Monascus purpureus Went on moist and sterile rice indicated the presence of a group of metabolites belonging to the monacolin family of polyketides, together with fatty acids, and trace elements. The presence of these compounds may explain in part the cholesterol-lowering ability associated with this traditional Chinese food.

Donor and recipient leukocytes in organ allografts of recipients with variable donor-specific tolerance: with particular reference to chronic rejection

We have attributed organ engraftment to clonal exhaustion-deletion of host-versus-graft and graft-versus-host reactions that are reciprocally induced and governed by migratory donor and recipient leukocytes. The so-called donor passenger leukocytes that migrate from the allograft into the recipients have been thoroughly studied (chimerism), but not the donor leukocytes that remain in, or return to, the transplanted organ. Therefore, using flow cytometry we determined the percentage and lineages of donor leukocytes in cell suspensions prepared from Lewis (LEW) cardiac allografts to 100 days posttransplantation. The LEW hearts were transplanted to naïve untreated Brown Norway (BN) recipients (group 2), to naïve BN recipients treated with a 28-day or continuous course of tacrolimus (TAC) (groups 3 and 4), and to drug-free BN recipients pretolerized by earlier bone marrow cell (BMC) or orthotopic LEW liver transplantation (groups 5 and 6). The findings in the heart cell suspensions were correlated with the results from parallel histopathologic-immunocytochemical studies and other studies of the grafts and of host tissues. Although the LEW heart allografts were rejected in 9.6 days by the unmodified recipients of group 2, all beat for 100 days in the recipients of groups 3 through 6. Nevertheless, all of the long-surviving cardiac allografts (but not the isografts in group 1) were the targets of an immune reaction at 5 days, reflected by dramatic increases in the ratio of leukocytes to nonleukocyte nucleated cells from normal values of 1:5-1:6 to 1:1-5:1 and by manifold other evidence of a major inflammatory event. The acute changes returned to baseline by 100 days in the chronic rejection (CR) free hearts of groups 4 and 6, but not in the CR-afflicted hearts of short-course TAC group 3 or the less-severely damaged hearts of the BMC-prime group 5. The freedom from CR in groups 4 and 6 was associated with a large donor contribution to the intracardiac leukocyte population at 5 days (28.6% and 22% in the respective groups) and at 100 days (30.5% in group 4 and 8.4% in group 6) compared with 2% and 1.2% at 100 days in the CR-blighted allografts of the partially tolerant animals of groups 3 and 5. Whether large or small, the donor leukocyte fraction always included a subset of class II leukocytes that had histopathologic features of dendritic cells. These class II(+) cells were of mixed myeloid (CD11b/c(+)) and lymphoid lineages; their migration was markedly inhibited by TAC and accelerated by donor-specific priming and TAC discontinuance. Although a large donor leukocyte population and a normal leukocyte/nonleukocyte cell ratio were associated with freedom from CR, these findings and the lineage profile of the intracardiac leukocytes were not associated with tolerance in the animals of groups 3 and 4 under active TAC treatment. The findings in this study, singly and in their entirety, are compatible with our previously proposed leukocyte migration-localization paradigm of organ allograft acceptance and tolerance.

Pain as a mutual experience for patients, nurses and families: a perspective from Shanghai, China

The author of this article visited China for the purpose of helping the faculty of the School of Nursing learn research skills by participating in research--a kind of learn by doing. Both investigators had conducted quantitative studies in the US--one with children and one with adults--that were adapted for use in China. Seeking to also include a qualitative study, the investigators explored several possible research areas. Because pain is a universal phenomena, it was chosen as the subject for the study using the qualitative methodology reported in the first part of this article.

Identification of a novel FAS/ER-alpha fusion transcript expressed in human cancer cells

A semi-nested reverse transcriptase-polymerase chain reaction (RT-PCR) was applied to evaluate the presence of estrogen receptor-alpha (ER-alpha) in human prostate cancer cells. Unexpectedly, a novel fatty acid synthase (FAS)/ER-alpha fusion transcript was identified, in which the N-terminus of FAS was fused in-frame with the C-terminus of ER-alpha. The existence of the FAS/ER-alpha transcript was further confirmed by RT-PCR analysis using various sets of amplification primers and different reverse-transcribed primers in the presence of dimethyl sulfoxide to eliminate the secondary structure of RNA. The predicted FAS/ER-alpha protein would contain largely domain I of FAS and the entire ligand binding domain of ER-alpha. The FAS/ER-alpha was expressed in a variety of human cancer cell lines including prostate, breast, cervical and bladder cancer cell lines. Our data suggest that the presence of FAS/ER-alpha may complicate the FAS and the ER-alpha signalling pathway.

[A clinicopathological study of hepatic focal nodular hyperplasia]

OBJECTIVE

To study the clinicopathological features of focal nodular hyperplasia (FNH).

METHODS

The clinicopathological characteristics of 25 cases of FNH were studied retrospectively. 20 cases followed for 6 to 47 months. All were evaluated by use of paraffin-embedded sections, special and immunohistochemical staining (EnVision method) and electron microscope.

RESULTS

17 female and 8 male FNH patients aged 14 to 58 (median 38) years of age, all alpha-fetoprotein negative, asymptomatic and normal biochemical liver tests in most cases. The macroscopic hallmark is a central stellate fibrotic scar, composed of fibrous connective tissue and tortuous blood vessels, the fibrous tissue radiated peripherally, dividing the mass into multiple, variably sized nodules, simulating the pattern of cirrhosis. Microscopically, multinodular proliferation of benign-appearing hepatocytes separated by bile-duct-containing fibrous septae that radiate from the central scar. Internodular bile duct proliferation is abundant and merge imperceptibly with the hepatocyte elements near the fibrous septa. Immunohistochemically, the keratin expessed by hepatocytes and by the proliferated bile ducts were similar. Electron microscopic examination found that the ultrastructure of tumor cells were similar to normal hepatocytes. 20 cases were followed for 6-47 months, all survived with no recurrence.

CONCLUSION

FNH is a benign hepatocytic lesion, i.e. a reactive proliferation of hepatic cells to local blood vessel anomalies.

[Effects on the adjacent segment after spinal fusion and instrumentation]

This paper reviewed the literatures about the pathology at the segments adjacent to the fusion segments. The hypertrophic degenerative arthritis of the facet joints and spinal stenosis were the most common pathologic conditions. The pathology usually occurred at the upper segment in the patients of spinal fusion; and the lower segment would also show degeneration in those of instrumentation. The reason lied mainly in the increased stress at the adjacent segment after surgery and the change of segmental motion pattern. Symptoms usually developed within the first 5 years after fusion. Diagnosis depends on the clinical manifest and X-ray examination. Surgical intervention should be indicated if the conservative therapy failed, and decompression and fusion were most commonly applied.

Hepatocellular adenoma and focal nodular hyperplasia: a series of 24 patients with clinicopathological and radiological correlation

OBJECTIVE

To investigate two rare benign lesions, hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH), and evaluate differential diagnosis.

METHODS

Twenty-four consecutive patients with presumed HCA and FNH were studied at the Liver Cancer Institute from January 1996 to May 1999. Preoperative assessment included clinical evaluation, symptoms and laboratory tests. New imaging techniques were prospectively appraised in addition to usual techniques. All had hepatic resections and follow-up. Histologic examination of surgical specimens was obtained in all cases.

RESULTS

In every instance, FNH was an incidental finding. FNH consists of nodular aggregates of cytologically normal hepatocytes with foci of intranocular bile duct proliferation. In this series, patients with HCA had larger tumors and more often were symptomatic but the occurrence was unrelated to oral contraceptive steroids (OCS) usage. Intralesional hemorrhage or necrosis is common, and was seen in 75% of cases. The best imaging procedure in the diagnosis of FNH was MRI. Color Doppler US was a useful adjunct, but CT lacked specificity, making histological diagnosis mandatory. All patients underwent tumor resected were tumor--free during the follow-up.

CONCLUSIONS

FNH is a distinct histopathologic entity, and is distinguishable from HCA. FNH is a hyperplastic response by the liver parenchyma to a pre-existing arterial malformation. HCA is a liver neoplasia and has the potential of malignant transformation to HCC. Based on these findings, we believe that if the clinical suspicion of HCA or FNH is strong, resection is usually the best approach if technically feasible and histologic diagnosis is mandatory.

[Pharyngeal plexus neurectomy for voice restoration of alaryngeal]

OBJECTIVE

To release the spasm of pharyngeal constrictor and raise the successful rate of voice rehabilitation in total laryngectomized patients wearing Blom-Singer prosthesis.

METHODS

The main branch of the pharyngeal plexus nerves within the inferior contractor can be found at the posterior side of hyoid greater cornu, which is about 6.5 mm from the back of constrictor. The spasm of the inferior constrictor can be resolved by cut off the nerve.

RESULTS

Voice restoration was achieved in 15 cases after pharyngeal plexus neurectomy, the successful rate was 93.75%.

CONCLUSION

It is feasible to replace pharyngeal myotomy by nerve plexus neurectomy and raise the voice rehabilitation rate.

Optical detection of polycations via polymer film-modified microtiter plates: response mechanism and bioanalytical applications

Microtiter plate wells modified with thin (approximately 20 microm) polymeric films capable of optically sensing macromolecular protamine and other polycationic species are described. The plates are prepared by coating the bottom of each well of a conventional 96-well polypropylene plate with an adherent polymer film (a mixture of poly(vinyl chloride) and polyurethane) containing a lipophilic 2',7'-dichlorofluorescein derivative. Surprisingly, optical response toward polycations is shown to result from the extraction of the fluorescein derivative from the polymer film into a lyophobic colloidal phase at the sample/film interface. This new phase is likely composed of a micellular-type ion pair complex between the analyte polycation from aqueous sample phase and the deprotonated form of the fluorescein derivative. Accumulation of the deprotonated fluorescein species in this interfacial region induces an absorbance change measured at 540 nm. Optimized plates can be used to sense protamine concentrations in the range of 0-100 microg/mL in 10 min with little or no response to physiological levels of common cationic species (Na+, K+, Ca2+, etc.). The modified plates are shown to be useful as simple optical detectors for measuring heparin levels in plasma via titrations with protamine and for monitoring protease activities (trypsin and plasmin) that cleave polycationic peptides/proteins such as protamine into smaller peptide fragments that are not detected by the sensing films. Assays for "clot busting" plasminogen activators (streptokinase, urokinase, and tissue plasminogen activator) are also demonstrated using this relatively simple microtiter plate-based polycation detection system.

[Cultivation integrated with acetate acid filtration on Escherichia coli]

A fed-batch fermentation integrated with filtration process was proceeded in a synthetic medium with the use of a hollow-fibre membrane filter. The activity of alpha A interferon reached 1.4 x 10(9) u/L, which was increased 320% over that of a control process. The integrated process was then proceeded in the synthetic medium supplemented with yeast extract during the earlier stage. The addition of yeast extract not only reduced the accumulation of acetate, but also promoted the production of alpha A interferon. The maximum activity achieved 1.9 x 10(9) u/L during the fermentation, which was increased 480% over that of a normal process.

[Follow-up study of total condylar knee arthroplasty with three types of Chinese knee prosthetics]

OBJECTIVE

To clinical evaluate the results of total condylar knee arthroplasty using three types of Chinese knee prosthesis.

METHODS

Hundred and two knees (in 92 patients) arthroplasty were performed in our department during the 14 years (April 1981-November 1995) were analyzed. The follow-up period averaged 64.4 months. Eight cases had died and 14 cases were lost of follow-up, leaving 80 knees in 70 patients for clinical evaluation. The clinical results were evaluated according to Hospital for Special Surgery Rating System.

RESULTS

The average preoperative score was 47.65 and the postoperative score was 90.23. Almost all patients achieved significant pain relief after operation. Sixty-one of the 70 patients (87%) reported that they satisfied or very satisfied with the results of surgery. There were 6 failures. One was due to deep infection, one with loose patellar component, and four directly related to either improper selection or technical reasons.

CONCLUSIONS

Total condylar knee arthroplasty with Chinese knee prosthetics gives a satisfactory grade of pain relief and movement of the operated knee. Chinese knee prosthetics is safety and durable.

Differential diagnosis between hepatic focal nodular hyperplasia and hepatocellular carcinoma with negative alhpa-fetoprotein

OBJECTIVE

To study the differential diagnosis between hepatic focal nodular hyperplasia (FNH) and hepatocellular carcinoma (HCC) with negative alpha-feto protein.

METHODS

To analyse retrospectively the clinical and imaging materials of 18 patients with FNH and 254 patients with AFP negative HCC proven by operation and pathology during March 1996 to March 1999 in our institute.

RESULTS

Patients with FNH were largely younger (66.7% under 40 years), discovered accidentally (66.7%), and without hepatitis background (83.3%). Majority of them had a normal liver function (72.0%). A big central artery was found in the lesion with high velocity and low resistant index in 71.4% of patients by color Doppler ultrasound. CT scan showed transient immediate enhancement in 85.7% of patients after bolus injection, being homogeneous (53.3%) and isodensity (73.3%) in the portal vein phase. MR imaging demonstrated early vigorous enhancement (83.3%) and homogenous (66.7%) lesion. In contrast, patients with AFP negative HCC were generally older (85.8% over 40 years), with symptoms (74.0%). A color flow with high velocity and high resistant index was found by color Doppler ultrasound. CT scan showed early heterogenous enhancement (96.6%) after bolus injection and being hypodensity in portal vein phase. MR imaging indicated early heterogeneous enhancement (91.7%).

CONCLUSION

FNH shows some typical clinical and imaging features. Therefore, it is feasible to be differentiated from HCC with negative AFP in some of the patients.

Fibrin gel as a three dimensional matrix in cardiovascular tissue engineering

OBJECTIVE

In tissue engineering, three-dimensional biodegradable scaffolds are generally used as a basic structure for cell anchorage, cell proliferation and cell differentiation. The currently used biodegradable scaffolds in cardiovascular tissue engineering are potentially immunogenic, they show toxic degradation and inflammatory reactions. The aim of this study is to establish a new three-dimensional cell culture system within cells achieve uniform distribution and quick tissue development and with no toxic degradation or inflammatory reactions.

METHODS

Human aortic tissue is harvested from the ascending aorta in the operation room and worked up to pure human myofibroblasts cultures. These human myofibroblasts cultures are suspended in fibrinogen solution and seeded into 6-well culture plates for cell development for 4 weeks and supplemented with different concentrations of aprotinin. Hydroxyproline assay and histological studies were performed to evaluate the tissue development in these fibrin gel structures.

RESULTS

The light microscopy and the transmission electron microscopy studies for tissue development based on the three-dimensional fibrin gel structures showed homogenous cell growth and confluent collagen production. No toxic degradation or inflammatory reactions could be detected. Furthermore, fibrin gel myofibroblasts structures dissolved within 2 days in medium without aprotinin, but medium supplemented with higher concentration of aprotinin retained the three-dimensional structure and had a higher collagen content (P<0.005) and a better tissue development.

CONCLUSIONS

A three-dimensional fibrin gel structure can serve as a useful scaffold for tissue engineering with controlled degradation, excellent seeding effects and good tissue development.

[Proportional assist ventilation: methodology therapeutics on COPD patients compared with pressure support ventilation]

OBJECTIVE

To establish the method for clinical use of proportional assist ventilation (PAV) and evaluate the effect on COPD patients. The main similarities and differences of PAV and pressure support ventilation (PSV) were described.

METHODS

10 ventilated patients of COPD were studied. The elastance and resistance were determined before PAV by both inspiratory-hold technique during a brief period of volume control ventilation and "runaway technique". Either different assist levels of PAV (% assist 80%, 60%, 40%, respectively) or PSV was selected randomly. Values of hemodynamics, blood gas and pulmonary mechanics were monitored. Patients' response was described also.

RESULTS

Runaway technique was convenient and reliable. Among different assist percentage no significant difference was found on hemodynamics in stabilized COPD patients. PaO2 was in a good level. Either tidal volume or respiratory rate did not change in a consistent way as the level of assist was decreased. But peak inspiratory pressure was increasing significantly r = 0.928 (P < 0.01) and patients' work of breath had the tendency to decrease (P < 0.05). A significant difference of Borg Category Scale was observed between PAV and PSV [0.50(1.50)] vs [0.75(2.00)], (P < 0.05). No significant difference of hemodynamics was found between the two modes. PaCO2 was significantly higher on PAV than on PSV, 54(24) and 48(23) mm Hg, respectively (P < 0.05). Peak inspiratory pressure on PAV (16 +/- 4) cm H2O was significantly lower than on PSV (21 +/- 3) cm H2O (P < 0.05).

CONCLUSIONS

PAV is a feasible method of supporting ventilator-dependent patients that is well tolerated. It can improve breathing pattern and reduce inspiratory effort by decreasing work of breath. PAV can be implemented at much lower peak inspiratory pressure than PSV at the same condition of work of breath by patients. It can also apply proportional pressure support according to patients' ventilatory demand. System that operates according to the theory of PAV is not easy to implement. How to measure elastance and resistance is still a question during the development of PAV.

Tissue engineering in cardiovascular surgery: new approach to develop completely human autologous tissue

OBJECTIVE

In cardiovascular tissue engineering, three-dimensional scaffolds serve as physical supports and templates for cell attachment and tissue development. Currently used scaffolds are still far from ideal, they are potentially immunogenic and they show toxic degradation and inflammatory reactions. The aim of this study is to develop a new method for a three-dimensional completely autologous human tissue without using any scaffold materials.

METHODS

Human aortic tissue is harvested from the ascending aorta in the operation room and worked up to pure human myofibroblasts cultures. These human aortic myofibroblasts cultures (1.5x10(6) cells, passage 3) were seeded into 15-cm culture dishes. Cells were cultured with Dulbecco' s modified Eagle's medium supplemented with 1 mM L-ascorbic acid 2-phosphate for 4 weeks to form myofibroblast sheets. The harvested cell sheets were folded to form four-layer sheets. The folded sheets were then framed up and cultured for another 4 weeks. Tissue development was evaluated by biochemical assay and light and electron microscopy.

RESULTS

After 4 weeks of culture in ascorbic acid supplemented medium, myofibroblasts formed thin cell sheets in culture dishes. The cell sheets presented in a multi-layered pattern surrounded by extracellular matrices. Cultured for additional 4 weeks on the frames, the folded sheets further developed into more solid and flexible tissues. Light microscopy documented a structure resembling to a native tissue with confluent extracellular matrix. Under transmission electron microscope, viable cells and confluent bundles of striated mature collagen fibers were observed. Hydroxyproline assays showed significant increase of collagen content after culturing on the frames and were 80.5% of that of natural human pericardium.

CONCLUSIONS

Improved cell culture technique may render human aortic myofibroblasts to a native tissue-like structure. A three-dimensional completely autologous human tissue may be further developed on the base of this structure with no show toxic degradation or inflammatory reactions.

A soluble form of human Delta-like-1 inhibits differentiation of hematopoietic progenitor cells

Two Notch ligand families, Delta and Serrate/Jagged, have been identified in vertebrates. Members of the Jagged family have been shown to affect in vitro hematopoiesis. To determine whether members of the Delta family might play a similar role in hematopoiesis, we examined the expression of mouse Delta-like-1 (mDll1). mDll1 protein was detected in whole marrow and in a marrow stromal cell line MS-5. At the RNA level, both mDll1 and Notch1 were seen in marrow precursor, differentiated hematopoietic, marrow stromal, and MS-5 cells. We isolated a cDNA encoding the human homologue of mDll1, designated human Delta-like-1 (hDll1). A soluble form of hDll1, hDll1(NDSL), containing the DSL domain and the N-terminal sequences, was expressed and purified from bacteria as a glutathione S-transferase (GST) fusion protein. We observed that hDll1(NDSL) delayed the acquisition of differentiation markers by murine hematopoietic progenitor cells (Lin-) cultured in vitro with cytokines. In addition, it promoted greater expansion (more than 3 times) of the primitive hematopoietic precursor cell population, measured in high-proliferative potential colony assay and day 12 colony-forming unit spleen (CFU-S) assay, than GST controls. We also observed that the percentage of apoptotic cells decreased and that the number of cells in the S-phase of the cell cycle increased in the cultures of Lin(-) cells with hDll1(NDSL). The effects of hDll1(NDSL) were blocked by antibody against the mouse counterpart of hDll1(NDSL), mDll1(NDSL). These observations demonstrate that hDll1 plays a role in mediating cell fate decisions during hematopoiesis. (Blood. 2000;95:1616-1625)

Crystal structure of CHO reductase, a member of the aldo-keto reductase superfamily

Chinese hamster ovary (CHO) reductase is an enzyme belonging to the aldo-keto reductase (AKR) superfamily that is induced by the aldehyde-containing protease inhibitor ALLN (Inoue, Sharma, Schimke, et al., J Biol Chem 1993;268: 5894). It shows 70% sequence identity to human aldose reductase (Hyndman, Takenoshita, Vera, et al., J Biol Chem 1997;272:13286), which is a target for drug design because of its implication in diabetic complications. We have determined the crystal structure of CHO reductase complexed with nicotinamide adenine dinucleotide phosphate (NADP)+ to 2.4 A resolution. Similar to aldose reductase and other AKRs, CHO reductase is an alpha/beta TIM barrel enzyme with cofactor bound in an extended conformation. All key residues involved in cofactor binding are conserved with respect to other AKR members. CHO reductase shows a high degree of sequence identity (91%) with another AKR member, FR-1 (mouse fibroblast growth factor-regulated protein), especially around the variable C-terminal end of the protein and has a similar substrate binding pocket that is larger than that of aldose reductase. However, there are distinct differences that can account for differences in substrate specificity. Trp111, which lies horizontal to the substrate pocket in all other AKR members is perpendicular in CHO reductase and is accompanied by movement of Leu300. This coupled with movement of loops A, B, and C away from the active site region accounts for the ability of CHO reductase to bind larger substrates. The position of Trp219 is significantly altered with respect to aldose reductase and appears to release Cys298 from steric constraints. These studies show that AKRs such as CHO reductase are excellent models for examining the effects of subtle changes in amino acid sequence and alignment on binding and catalysis.

Glyoxal-guanine DNA adducts: detection, stability and formation in vivo from nitrosamines

The glyoxal-deoxyguanosine adduct (gG) is formed from alpha-nitrosamino aldehydes and dG in vitro and in vivo from nitrosamines carrying the 2-hydroxyethyl side-chain as well as from N-nitrosomorpholine. The structures of all of the diastereomeric forms of both the cis and trans isomers of the adduct have been investigated by ab initio calculations and with nuclear magnetic resonance spectroscopy at 500 MHz. The preferred orientation of the OH groups is trans, but at equilibrium a small amount of the cis isomer was observed. The pH-independent equilibrium constant for the hydrolysis of the gG adduct is K = 1.36 x 10(-4) mol/L, and its rate of formation at pH 7.3 is k = 5.3 min-1 mol-1. In acid (pH 2), the hydrolysis of the nucleosidic linkage is nearly twice as rapid as the hydrolysis of gG to glyoxal and dG. We used a gG analogue to explore a number of reductive methods for derivatization of the adduct, but all of the processes either gave low yields or product mixtures which rendered them impractical for derivatizing the adduct in DNA. A 32P-postlabelling method for detection of the pH-sensitive gG adduct has been developed, which permitted detection of the adduct in the liver DNA of male Wistar rats after administration of selected nitrosamines. The levels of adducts found were: N-nitrosodiethanolamine > 2-hydroxyethylmethynitrosamine > N-nitrosomorpholine > 2-hydroxyethyethylnitrosamine. In separate experiments, N-nitrosodiethanolamine gave greater adduct levels than its metabolite 2-hydroxy-N-nitrosomorpholine. Mechanistic pathways for the generation of gG adducts in vitro and in vivo are discussed.

Frequency of collateral blood flow in the infarct-related coronary artery in rupture of the ventricular septum after acute myocardial infarction

Patients with postinfarction ventricular septal rupture have poor residual or collateral blood flow in the infarct artery and do not benefit from ischemic preconditioning. This suggests that rupture of the ventricular septum occurs on an unprotected and unprepared myocardium.

DepoFoam technology: a vehicle for controlled delivery of protein and peptide drugs

A major challenge in the development of sustained-release formulations for protein and peptide drugs is to achieve high drug loading sufficient for prolonged therapeutic effect coupled with a high recovery of the protein/peptide. This challenge has been successfully met in the formulation of several peptide and protein drugs using the DepoFoam, multivesicular lipid-based drug delivery system. DepoFoam technology consists of novel multivesicular liposomes characterized by their unique structure of multiple non-concentric aqueous chambers surrounded by a network of lipid membranes. The objective of this paper is to demonstrate that DepoFoam technology can be used to develop sustained-release formulations of therapeutic proteins and peptides with high loading. DepoFoam formulations of a protein such as insulin, and peptides such as leuprolide, enkephalin and octreotide have been developed and characterized. The data show that these formulations have high drug loading, high encapsulation efficiency, low content of free drug in the suspension, little chemical change in the drug caused by the formulation process, narrow particle size distribution, and spherical particle morphology. Drug release assays conducted in vitro in biological suspending media such as human plasma indicate that these formulations provide sustained release of encapsulated drug over a period from a few days to several weeks, and that the rate of release can be modulated. In vivo pharmacodynamic studies in rats also show a sustained therapeutic effect over a prolonged period. These results demonstrate that the DepoFoam system is capable of efficiently encapsulating therapeutic proteins and peptides and effectively providing controlled delivery of these biologically active macromolecules.

Histological reaction of auditory bulla bone to synthetic auditory ossicle (Apaceram) in rats

To investigate the biocompatibility of a synthetic auditory ossicle to host bone, small thin Apaceram disks composed of dense hydroxyapatite were implanted under the periosteum of the left auditory bulla in 32 rats for periods ranging from 1 day to 270 days. A sham operation performed on 10 rats served as a control. Decalcified histological sections stained with hematoxylin and eosin were observed using light microscopy. The experiment showed: 1) a time-dependent mature fibrous connective tissue surrounding the Apaceram disk, 2) no evidence of inflammatory reaction caused by the implant from 90 days after implantation until the end of the experiment, 3) no evidence of osteolysis by osteoclasts caused by the implant, and 4) direct contact of bone to the implant on the bone-disk interface at 180 and 270 days after implantation. The findings suggest that Apaceram has a high degree of implant biocompatibility, making it a satisfactory substitute biomaterial for otological reconstructive surgeries.

[The relationship of polymorphism of angiotensinogen and angiotensin converting enzyme with essential hypertension]

OBJECTIVE

In order to investigate the candidate genes for essential hypertension(EH), the authors determined the frequencies of M235T allele variation in exon 2 of angiotensinogen(AGT) gene and angiotensin converting enzyme (ACE) gene in 95 normotensives and 87 hypertensives in Chinese.

METHODS

Polymerase chain reaction combined with restriction enzyme digestion was used to detect the variation AGT gene while PCR was used to determine ACE gene polymorphism.

RESULTS

T235 allele frequency was significantly higher in hypertensive patients than in controls (0.45 vs 0.33, P<0. 05) and it was noticeably higher in male hypertensives. The frequency of ACE D allele in the EH patients with family history was higher than that in controls(0.59 vs 0.41,P<0.05).

CONCLUSION

The variation of AGT gene was involved in the pathogenesis of hypertension, especially in male. The ACE D allele was associated with EH with family history.

Crystal structure of CHO reductase, a member of the aldo-keto reductase superfamily

Chinese hamster ovary (CHO) reductase is an enzyme belonging to the aldo-keto reductase (AKR) superfamily that is induced by the aldehyde-containing protease inhibitor ALLN (Inoue, Sharma, Schimke, et al., J Biol Chem 1993;268: 5894). It shows 70% sequence identity to human aldose reductase (Hyndman, Takenoshita, Vera, et al., J Biol Chem 1997;272:13286), which is a target for drug design because of its implication in diabetic complications. We have determined the crystal structure of CHO reductase complexed with nicotinamide adenine dinucleotide phosphate (NADP)+ to 2.4 A resolution. Similar to aldose reductase and other AKRs, CHO reductase is an alpha/beta TIM barrel enzyme with cofactor bound in an extended conformation. All key residues involved in cofactor binding are conserved with respect to other AKR members. CHO reductase shows a high degree of sequence identity (91%) with another AKR member, FR-1 (mouse fibroblast growth factor-regulated protein), especially around the variable C-terminal end of the protein and has a similar substrate binding pocket that is larger than that of aldose reductase. However, there are distinct differences that can account for differences in substrate specificity. Trp111, which lies horizontal to the substrate pocket in all other AKR members is perpendicular in CHO reductase and is accompanied by movement of Leu300. This coupled with movement of loops A, B, and C away from the active site region accounts for the ability of CHO reductase to bind larger substrates. The position of Trp219 is significantly altered with respect to aldose reductase and appears to release Cys298 from steric constraints. These studies show that AKRs such as CHO reductase are excellent models for examining the effects of subtle changes in amino acid sequence and alignment on binding and catalysis.

Role of myocardial revascularization in postinfarction ventricular septal rupture

BACKGROUND

Postinfarction ventricular septal rupture requires urgent closure. The role of systematic coronarography and coronary revascularization needs clarification.

METHODS

Fifty-four patients who underwent patch closure of postinfarction ventricular septal defect were reviewed. A coronarography had been systematically and myocardial revascularization selectively (when significant coronary artery stenosis existed) performed.

RESULTS

No patient died or deteriorated during coronarography. Twenty-six patients showed no coronary artery disease besides the infarct-related artery, and 28 had associated disease. Threatened myocardial territories were revascularized usually with venous grafts (mean number of distal anastomosis, 2.5). Operative mortality was 19% and 32% (p = 0.36) and late mortality 43% and 53% (p = 0.75) in patients without and in patients with associated coronary artery disease, respectively. Survival curve in both group was similar, at least up to 8 years after operation.

CONCLUSIONS

Myocardial revascularization controlled the added risk of associated coronary artery disease in the postoperative period and in median term. A coronarography should be performed in all patients who can be stabilized hemodynamically and myocardial revascularization performed in case of significant stenosis.

[Monitoring glucoamylase fermentation with infrared spectroscopy]

The glucoamylase fermentation was investigated with Fourier transform infrared spectroscopy. During the cultivation, the variation of carbon and nitrogen source can be reflected from the infrared spectra. In most cases, the complex media are used to cultivate cells or bacteria. It is difficult to construct calibration samples with synthetic mixtures which can represent the composition of real broth. The infrared spectral data of the real broth and off-line chemical analysis results were used to establish the calibration model. The model is successfully used to predict the concentrations of total sugar, reduced sugar, and nitrogen in real broth. The correlation coefficients between the infrared analysis results and chemical analysis are 0.999, 0.990 and 0.974 for total sugar, reduced sugar and nitrogen, respectively. The bacteria, culture and operating condition are relatively stable during the practical productive processes. The method can be used to monitor the industrial processes.

Surgical repair of postinfarction structural failure of the posterobasal part of the heart

BACKGROUND

This study is an analysis of our results with endoventricular repair of postinfarction structural defects of the posterobasal part of the heart.

METHODS

Thirty-four patients who underwent endoventricular repair of a postinfarction structural defect of the posterobasal heart were reviewed. Patients with rupture of the ventricular septum (18 patients) or free wall (1 patient) were operated on acutely and patients with ventricular aneurysm (15 patients) electively. Restitution of the ventricular geometry was achieved by evertion (11 patients), resection (4 patients), or augmentation of the ventriculotomy (4 patients) in patients with ventricular rupture, and by resection of the aneurysm in the others. Coronary artery bypass was performed in 24 patients.

RESULTS

Six patients died postoperatively (five due to rupture and one from aneurysm) and nine patients (six due to rupture and three from aneurysm) during follow-up. Survival rate at 5 years (including operative mortality) was 43% for patients with rupture and 61% for patients with aneurysm. The majority of the survivors were in New York Heart Association functional class I or II after a median follow-up of 5 years.

CONCLUSIONS

Endocardial repair, ventricular remodeling, and selective myocardial revascularization provided overall good results in the treatment of this difficult cardiac area.

[A novel alternative splicing mode of the erythropoietin receptor gene in rats]

OBJECTIVE

To detect new alternative splicing mode of erythropoietin receptor (EpoR) gene in normal rats.

METHODS

Total RNAs were isolated from bone marrow mononuclear cells of normal Wistar rats. Reverse transcriptase polymerase chain reaction (RT-PCR) of the total RNAs was done and the amplified products were sequenced.

RESULTS

After RT-PCR with a pair of primers (sense: 637/657 bp, and antisence: 903/882 bp), two bands were detected, the expected band (267 bp) and a longer one (346 bp) which had a 79 bp insert between 736th and 737th bases from the first ATG of the rat EpoR nucleotide. Sequence analysis showed that the 79 bp insert was the retaining intron 5 with a C-to-T point mutation at 16th base and an insertion of G base between 49th and 50th base. The insertion of G base caused a shift in reading frame and resulted EpoR with a truncated intracellular domain.

CONCLUSION

A new alternative splicing of EpoR mRNA encoding truncated intracellular domain was identified in normal Wistar rats. Its implication in rat erythropoiesis remains to be determined.

Recent experience with the arterial switch operation in transposition of the great arteries

OBJECTIVE

Review of our experience with the technically demanding arterial switch operation in transposition of the great arteries in children.

METHODS

Twenty-seven children who underwent an arterial switch operation in our clinic were retrospectively reviewed. Except for one child (operated on at eight months), the operation was performed during the neonatal period. The underlying pathology was d-transposition of the great arteries in 25 children and a double outlet right ventricle of transposition type in 2. Five children had an associated ventricular septum defect and 1 aortic isthmus coarctation. The pattern of the coronary arteries was favourable in 18 children, difficult in 7 and dangerous in 3. The operation was performed in cardiopulmonary bypass for repair of the transposition and in a period of deep hypothermic circulatory arrest for repair of the intracardiac defects.

RESULTS

One child died perioperatively and 1 postoperatively (operative mortality 7%) from myocardial ischaemia following unsuccessful transfer of a dangerous pattern of coronary arteries. Another child, a low-birth weight baby, died 80 days after the operation from respiratory failure. Postoperative morbidity occurred in 10 patients and medium-term morbidity in 6 patients who presented various degrees of stenosis of a pulmonary artery. During a median follow-up of 18 months no patient required reoperation. The children are asymptomatic and thriving satisfactorily.

CONCLUSION

Because it restores the heart physiology, the arterial switch operation is considered the procedure of choice for correction of transposition of the great arteries. The operation involves acceptable mortality and morbidity. Transfer of difficult coronary artery patterns and development of stenosis on the pulmonary arteries remain problematic.

Operative results of "repair" of ventricular septal rupture after acute myocardial infraction

Fifty-four consecutive patients with postinfarction ventricular septal defect were reviewed. The rupture was closed with a patch and the left ventricle remodeled in all patients. Coronary artery bypass surgery was performed in 28 patients (52%). Fourteen patients (26%) died after operation and 19 during follow-up (mean 42 months). Cumulative survival (including operative deaths) was 78%, 65%, and 40% at 1, 5, and 10 years, respectively. A short interval between septal rupture and operation was a risk factor for early mortality (p = 0.03). Treated associated coronary artery disease had no effect. A residual septal shunt, detected in 10 patients (18%), warranted reoperation in 7 and contributed to 2 early and 1 late death. The location and morphology of the septal rupture were not associated with increased risk of residual shunt. Thus, patch closure of the ventricular septal rupture, remodeling of the left ventricle to improve stroke volume and reduce wall stress, and selective myocardial revascularization provided acceptable results.

Long-term microstructural analyses of hydroxyapatite implanted in rats using laser-Raman spectrometry and scanning electron microscopy

To investigate the long-term surface microstructure of a synthetic auditory ossicle (Apaceram) composed of dense hydroxyapatite (HA), thin HA disks were implanted subcutaneously into the interscapular regions of 12 rats. After 6, 14 and 20 months, implanted HA surfaces were observed using stereoscopic microscopy, scanning electron microscopy (SEM) and laser-Raman spectrometry. Visual observation by SEM at 6 months and by stereoscopic microscopy at 14 months indicated a progressive degradation of the HA disk surfaces implanted in the subcutaneous tissue. Visual observation by SEM at 14 and 20 months and by stereoscopic microscopy at 20 months indicated a progressive redeposition on the surfaces of the implants. Raman spectra compared half-peak breadths of v1 signal (PO4(3-), 960 cm(-1)) on the gray and white surface areas of implanted HA disks observed by stereoscopic microscopy. Analysis demonstrates that demineralization at 14 months and remineralization at 20 months occur on the gray areas; demineralization at 6 months and remineralization at 14 months occur on the white areas.

Existence of multiple novel Gs alpha splice variants in acute leukemia patients

The alpha subunit of the stimulatory G protein, Gs alpha, is involved in stimulation of the adenylate cyclase pathway of signal transduction. In this study, we investigated the status of the Gs alpha gene in 29 acute leukemia patients and identified three novel splice variants (designated Gs alpha L-1, Gs alpha L-2, and Gs alpha L-3), possibly derived from aberrant splicing. All of the splice variants have in-frame deletions, removing the functional domain responsible for GTPase activity of Gs alpha, and would encode truncated proteins of 160(Gs alpha L-1), 90(Gs alpha L-2) and 70(Gs alpha L-3) amino acids, respectively. The data suggest that these novel products may be implicated in an as-yet-unidentified signal transduction pathway in hematopoietic cells.

Failure and complication following surgical treatment of scoliosis--an analysis of 101 cases

Complications occur frequently after surgical treatment of scoliosis. In order to prevent from them effectively, 101 cases with failure and postoperative complications were analysed. They included rod fracture in 22 cases (15 Harrington rods, 4 Zielke rods, and 3 Luque rods); recurrence of curve severity in 12 cases; broken or loossened luque wires in 15 cases; loss of thoracic kyphosis (flat back) in 6 cases; progressive kyphosis with or without paraplegia following incorrect posterior decompression in 5 cases; and increased unbalance of shoulders after instrumentation in 2 cases due to neglect of the tilting of the first thoracic vertebra. Infection occurred in 8 cases (incision infection 7 cases, deep wound infection in 1 case); and pneumothorax in 1 case. They were induced by biomechanical factors in 23 cases (22.8%), incorrect selections of indications in 29 cases (28.7%), operational mistakes in 37 cases (36.6%), internal fixation factors in 15 cases (14.9%). The authors hold that there are quite a lot of factors leading to occurrence of complications and the effective way for prevention from them is to understand the factors and main technical points related to internal fixation.

Tissue engineering of a bioprosthetic heart valve: stimulation of extracellular matrix assessed by hydroxyproline assay

Creation of an autologous heart valve by tissue engineering offers a promising approach to cardiac surgery. Although we have demonstrated successful formation of native valve analogous tissue in vitro, hemodynamic competence remains a serious problem. The aim of this study was to optimize in vitro formation of collagen as a precondition for mechanical stability of new tissue. Human myofibroblasts were seeded on square sheets of biodegradable scaffolds (control). To stimulate collagen production, one series was cultured with L-ascorbic acid 2-phosphate. In a second series, the seeded scaffolds were subjected to tension by mounting them on a frame. After 4 weeks of culture time, the collagen content of the different series was assessed by hydroxyproline assay. Light and scanning electron microscopy were performed. Hydroxyproline content of the framed scaffolds was 10 times higher than that of the control group (p < 0.05) and 6 times higher than in the unframed scaffolds grown with ascorbic acid (p < 0.05), respectively. Scanning electron microscopy proved extensive formation of solid tissue in the framed samples. These results demonstrate that supplementation of myofibroblast cultures with ascorbic acid, especially if grown on strained scaffolds, significantly increases collagen content, which is crucial for mechanical stability. This concept is a further step toward the creation of a hemodynamically competent autologous heart valve.

Dendritic cells/chimerism/alleviation of chronic allograft rejection

Chronic rejection (CR) is the major obstacle of long-term successful organ transplantation. Using a recently developed rat model of CR, we found that heart allografts susceptible to development of CR showed an early (< 10 days) dramatic disappearance of donor MHC class II+ cells, including ED2+ tissue macrophages, and an influx of recipient ED1+ macrophages intermixed with small numbers of recipient ED2+ and OX62+ cells. In contrast, donor MHC class II+ cells persisted in allografts resistant to CR with a small influx of recipient macrophages. MHC class II+ cells function as potent modulators of the immune system and may mediate both stimulatory and tolerogenic immune reactions after transplantation. Persistence of donor MHC class II+ antigen-presenting cells (APC) in CR-free graft acceptance suggests that transplantation tolerance is an active immune response requiring antigen presentation to the recipient immune system in the proper context by dendritic cells and other APC.

Crystallization and X-ray crystallographic analysis of m-calpain, a Ca2+-dependent protease

The absolute requirement of Ca(2+) for proteolytic activity is a feature unique to the calpains, a family of heterodimeric cysteine proteases. Conditions are described which give rise to diffraction-quality crystals of m-calpain in two crystal forms, P1 and P2(1). Data have been collected from native crystals of m-calpain in both P1 and P2(1) forms, to 2.6 and 2.15 A, respectively. Selenomethionine-containing crystals have been grown in both forms, and anomalous data from the P2(1) selenomethionine enzyme provided the location of 17 of the 19 Se atoms in the protein.

[Treatment of late thoracolumbar fracture by transpedicular decompression using "PUMC trephine" 26 cases report]

OBJECTIVE

To introduce a new operation to treat late thoracolumbar fracture cases with neurological deficit or with kyphosis.

METHODS

26 cases were treated with "PUMC trephine" (designed by professor Ye Qibin).

RESULTS

The kyphosis was (29.7 +/- 14.5) degrees Cobb's angle in pre-operation and (10 +/- 11.8) degrees in post-operation (P < 0.01). The angle of correction was (19.7 +/- +9.9) degrees. The height of the anterior edge of traumatic-vertebra was (16.3 +/- 5.7) mm in pre-operation and (22.2 +/- 6.3) mm in post-operation. The corrected height was (6.5 +/- 3.2) mm. The neurological deficit also got a better recovery in 17 of 19 cases, 12 of 15 cases obtained complete cure of incontinence. 11 of 15 case had sexual function recovery after following up 1-9 years (average 5.2 years) cases.

CONCLUSIONS

Using "PUMC trephine" procedure was a new, simple, safety and less-traumatic technique for treatment of late thoracolumbar fracture through posterior approach.

[Study of the relation between MMP2, MMP9 and nasopharyngeal carcinoma]

OBJECTIVE

To evaluate the role of matrix metalloproteinase (MMP) in the invasion and metastasis of nasopharyngeal carcinoma (NPC).

METHOD

Twenty-six cases of NPC were studied by immunohistochmical method using monocolonal antibody to MMP2 and MMP9.

RESULT

It was showed that there were significantly correlation between MMP2 or MMP9 and the invasion and metastasis of NPC. The positive rate of MMP2 and MMP9 were higher in NPC with cervical lymph node involvement than that of no cervical lymph node involvement. And they were lower in well differentiated NPC than poorly differentiated NPC.

CONCLUSION

The results indicate that MMP2 and MMP9 may play a critical role in assisting carcinoma cell to degrade basement membrane to invade surrounding tissues and to form metastatic colonies in lymph nodes.

Thickness of fibrous capsule after implantation of hydroxyapatite in subcutaneous tissue in rats

The present study evaluates in rats the histomorphometrical thickness of fibrous capsules that surround hydroxyapatite (HA) disks after implantation. HA disks were implanted into the subcutaneous tissue of 79 rats for 1 day to 20 months. Decalcified histological sections stained with hematoxylin and eosin were examined. Fibrous capsule thickness (FCT) was measured using an objective micrometer. On the fourteenth day, primary fibrous capsules formed around implants. From that time point FCT increased with time of implantation. Within a given sample, FCT differed from one portion of the fibrous capsule to another, depending on which site faced the disks. FCT was thickest at the upper and lower portions of the disks, thinner at the lateral portions, and thinnest at the upper and lower ring-shaped portions. Two possible explanations for the above findings are discussed in this paper: (1) The area of contact between disk and tissue differs. (2) Chemical stimulation of implanted material caused by demineralization and remineralization may result from the varying thicknesses of fibrous capsules. FCT from upper and lower portions of HA disks increased by over 200% in the first 10 months and steadily increased about 20% over the next 10 months. Many studies have concluded that HA is useful for reconstructive surgery, so the long-term effects of FCT need further study.

Crystallization and preliminary X-ray crystallographic analysis of spruce budworm antifreeze protein

Antifreeze proteins have the ability to bind to ice with high affinity and inhibit further crystal growth. The insect antifreeze protein from spruce budworm exhibits very high thermal hysteresis activity and is implicated in the protection of overwintering larvae from freezing. This protein has been crystallized in 20-25% polyethylene glycol (Mr 6000), 0.4 M NaCl, 0.1 M Tris-HCl, pH 8.5, by vapor diffusion using the hanging drop method. The resulting crystals are very thin (typically <0.01 mm in the shortest dimension), and only after repeated seeding could crystals be grown large enough for data collection using synchrotron radiation. The crystals belong to the monoclinic space group C2, with cell dimensions a = 82.28 A, b = 62.29 A, c = 63.63 A, and beta = 113.7 degrees. Molecules in the asymmetric unit are related by a twofold axis of symmetry with two molecules present. Native data to a resolution of 2.6 A have been collected with 90.3% completeness and a Rsym of 6.9%.

Subunit mutations affect ethanol actions on GABA(A) receptors expressed in Xenopus oocytes

1. Mutations of specific amino acids were introduced in transmembrane domains (TM) of GABA(A) receptor alpha2, beta1 and gamma2L subunits. The effects of these mutations on the action of ethanol were studied using the Xenopus oocyte expression system and two-electrode voltage-clamp recording techniques. 2. Mutant alpha2 subunits containing S270I (TM2) or A291W (TM3) made the receptor more sensitive to GABA, as compared to wild-type alpha2beta1gamma2L receptor. The mutation S265I (TM2) of beta1 and S280I (TM2) or S30IW (TM3) in gamma2L subunits did not alter apparent affinity of the receptor for GABA. M286W (TM3) in the beta1 subunit resulted in a receptor that was tonically open. 3. Using an EC5 concentration of GABA, the function of the wild-type receptor with alpha2beta1gamma2L subunits was potentiated by ethanol (50-200 mM). The mutations in TM2 or TM3 of the alpha2 subunit diminished the potentiation by ethanol. The action of ethanol was also eliminated with a mutation in the TM2 site of the beta1 subunit. Ethanol produced significant inhibition of GABA responses in receptors containing the combination of alpha2 and beta1 TM2 mutants with a wild-type gamma2L subunit. A small but significant reduction in the potentiation by ethanol was observed with gamma2L TM2 and/or TM3 mutants. 4. From these results, we suggest that in heteromeric GABA(A) receptors composed of the alpha, beta and gamma subunits, ethanol may bind in a cavity formed by TM2 and TM3, and that binding to the alpha or beta subunit may be more critical than the gamma subunit.

[The surgical treatment of congenital kyphosis]

OBJECTIVE

To summarize the treatment experience of congenital kyphosis, compare the results of several surgical procedures and conclude the lessons of failure cases with surgical treatment.

METHODS

Retrospective analysis of 33 patients with surgical treatment of congenital kyphosis. These patients had a follow-up of 6 months to 14 years with an average follow-up of 5 years and 6 months.

RESULTS

Among the 33 cases, the average age at surgery was 16.5 years old and the average kyphosis was 90.2 degrees. Four had anterior fusion, and 7 had posterior fusion only, and 22 had combined anterior and posterior fusion. The percentage of correction of the 3 procedures above mentioned was 32.7%, 34.4% and 41.2% respectively. All of the patients with incomplete paraplegia, but 2 had been recovered completely.

CONCLUSIONS

The combined anterior and posterior fusion had a better correction than the anterior group or posterior group alone.

Tissue engineering in cardiovascular surgery: MTT, a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshes

OBJECTIVE

Currently used valve substitutes for valve replacement have certain disadvantages that limit their long-term benefits such as poor durability, risks of infection, thromboembolism or rejection. A tissue engineered autologous valve composed of living tissue is expected to overcome these shortcomings with natural existing biological mechanisms for growth, repair, remodeling and development. The aim of the study was to improve cell seeding methods for developing tissue-engineered valve tissue.

METHODS

Human aortic myofibroblasts were seeded on polyglycolic acid (PGA) meshes. Cell attachment and growth of myofibroblasts on the PGA scaffolds with different seeding intervals were compared to determine an optimal seeding interval. In addition, scanning electron microscopy study of the seeded meshes was also performed to document tissue development.

RESULTS

There was a direct correlation between cell numbers assessed by direct counting and MTT(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltertra-zoliu m bromide) assay. Both attach rate and cell growth seeded on meshes with long intervals (24 and 36 h) were significantly higher than those seeded with short intervals (2 and 12 h) (P<0.01), there was no significant difference between 24- and 36-h seeding interval. Scanning electron microscopy also documented more cell attachment with long seeding intervals resulting in a more solid tissue like structure.

CONCLUSION

It is feasible to use human aortic myofibroblasts to develop a new functional tissue in vitro. Twenty-four hours is an optimal seeding interval for seeding human aortic myofibroblasts on PGA scaffolds and MTT test is a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshes.

[Investigation of the reaction of iso-propylamine on propylene oxide by Fourier transform infrared spectroscopy]

Fourier transform infrared spectroscopy method has been developed for in-situ monitoring the reaction of iso-propylamine on propylene oxide without the need to sample the reaction medium. The profile of the reaction and the influences of conditions can be directly reflected in the feature absorbance changes of the reactant and product at 826 cm(-1) and 1069 cm(-1), respectively. It is shown that the in situ infrared spectroscopy is a powerful technique to investigate the mechanism and kinetics of the reaction and to optimize the control conditions.

Donor hematopoietic progenitor cells in nonmyeloablated rat recipients of allogeneic bone marrow and liver grafts

BACKGROUND

Although the persistence of multilineage microchimerism in recipients of long-surviving organ transplants implies engraftment of migratory pluripotent donor stem cells, the ultimate localization in the recipient of these cells has not been determined in any species.

METHODS

Progenitor cells were demonstrated in the bone marrow and nonparenchymal liver cells of naive rats and in Brown Norway (BN) recipients of Lewis (LEW) allografts by semiquantitative colony-forming unit in culture (CFU-C) assays. The LEW allografts of bone marrow cells (BMC) (2.5x10(8)), orthotopic livers, or heterotopic hearts (abdominal site) were transplanted under a 2-week course of daily tacrolimus, with additional single doses on days 20 and 27. Donor CFU-C colonies were distinguished from recipient colonies in the allografts and recipient bone marrow with a donor-specific MHC class II monoclonal antibody. The proportions of donor and recipient colonies were estimated from a standard curve created by LEW and BN bone marrow mixtures of known concentrations.

RESULTS

After the BMC infusions, 5-10% of the CFU-C in the bone marrow of BN recipients were of the LEW phenotype at 14, 30, and 60 days after transplantation. At 100 days, however, donor CFU-C could no longer be found at this site. The pattern of LEW CFU-C in the bone marrow of BN liver recipients up to 60 days was similar to that in recipients of 2.5x10(8) BMC, although the donor colonies were only 1/20 to 1/200 as numerous. This was expected, because the progenitor cells in the passenger leukocytes of a single liver are equivalent to those in 1-5x10(6) BMC. Using a liquid CFU-C assay, donor progenitor cells were demonstrated among the nonparenchymal cells of liver allografts up to 100 days. In contrast, after heart transplantation, donor CFU-C could not be identified in the recipient bone marrow, even at 14 days.

CONCLUSION

effective immunosuppression, allogeneic hematopoietic progenitors compete effectively with host cells for initial engraftment in the bone marrow of noncytoablated recipients, but disappear from this location between 60 and 100 days after transplantation, coincident with the shift of donor leukocyte chimerism from the lymphoid to the nonlymphoid compartment that we previously have observed in this model. It is possible that the syngeneic parenchymal environment of the liver allografts constitutes a privileged site for persistent progenitor donor cells.