Restoration of dystrophin expression in mdx mice by intravascular injection of naked DNA containing full-length dystrophin cDNA

Duchenne muscular dystrophy (DMD) is a lethal, X-linked, recessive disease caused by a defect in the dystrophin gene. No effective therapy is available. Dystrophin gene transfer to skeletal muscle has been proposed as a treatment for DMD. However, successful treatment for DMD requires restoration of dystrophin in the affected muscle fibers to at least 20% of the normal level. Current gene transfer methods such as intramuscular injection of viral vector or naked DNA can only transfect a small area of muscle, and therefore is of little clinical utility. We have developed a semisystemic method for gene transfer into skeletal muscle of mdx mice, an animal model for DMD. Naked DNA was injected through the tail artery or vein of mice, in which the aorta and the vena cava were clamped at the location just below the kidneys. The DNA solution was thus forced into the blood vessels of both legs. Luciferase gene expression was detected in all muscle groups in both legs. The effects of injection speed, injection volume, and ischemia time on gene expression were also optimized. LacZ staining was used to check the spread of gene expression in muscle. Although the percentage of transfected fibers was modest (approximately 10%), beta-galactosidase was found in all muscle groups of both legs. Finally, plasmid DNA encoding full-length dystrophin gene was injected into mdx mice and widespread restoration of dystrophin protein was observed in all muscles of both hind limbs. In conclusion, these results demonstrate that the semisystemic delivery of naked DNA is a potential approach towards the long-term goal of gene therapy for DMD.

Deficiency of the cysteine protease cathepsin S impairs microvessel growth

During angiogenesis, microvascular endothelial cells (ECs) secrete proteinases that permit penetration of the vascular basement membrane as well as the interstitial extracellular matrix. This study tested the hypothesis that cathepsin S (Cat S) contributes to angiogenesis. Treatment of cultured ECs with inflammatory cytokines or angiogenic factors stimulated the expression of Cat S, whereas inhibition of Cat S activity reduced microtubule formation by impairing cell invasion. ECs from Cat S-deficient mice showed reduced collagenolytic activity and impaired invasion of collagens type I and IV. Cat S-deficient mice displayed defective microvessel development during wound repair. This abnormal angiogenesis occurred despite normal vascular endothelial growth factor and basic fibroblast growth factor levels, implying an essential role for extracellular matrix degradation by Cat S during microvessel formation. These results demonstrate a novel function of endothelium-derived Cat S in angiogenesis.

Structure of protein tyrosine phosphatase 1B in complex with inhibitors bearing two phosphotyrosine mimetics

Protein tyrosine phosphatases (PTPases) are signal-transducing enzymes that dephosphorylate intracellular proteins that have phosphorylated tyrosine residues. It has been demonstrated that protein tyrosine phosphatase 1B (PTP1B) is an attractive therapeutic target because of its involvement in regulating insulin sensitivity (Elcheby et al. Science 1999, 283, 1544-1548). The identification of a second binding site in PTP1B (Puius et al., Proc. Natl. Acad. Sci. U.S.A.1997, 94, 13420-13425) suggests a new strategy for inhibitor design, where appropriate compounds may be made to simultaneously occupy both binding sites to gain much higher affinity and selectivity. To test this hypothesis and gain further insights into the structural basis of inhibitor binding, we have determined the crystal structure of PTP1B complexed with two non-peptidyl inhibitors, 4 and 5, both of which contain two aryl difluoromethylenephosphonic acid groups, a nonhydrolyzable phosphate mimetic. The structures were determined and refined to 2.35 and 2.50 A resolution, respectively. Although one of the inhibitors seems to have satisfied the perceived requirement for dual binding, it did not bind both the active site and the adjacent noncatalytic binding site as expected. The second or distal phosphonate group instead extends into the solvent and makes water-mediated interactions with Arg-47. The selectivity of the more potent of these two inhibitors, as well as four other inhibitors bearing two such phosphate mimetics for PTP1B versus seven other PTPases, was examined. In general, selectivity was modest to good when compared to PTPases Cdc25a, PTPmeg-1, PTPbeta, and CD45. However, selectivity was generally poor when compared to other PTPases such as SHP-1, SHP-2, and especially TCPTP, for which almost no selectivity was found. The implications these results have concerning the utility of dual-binding inhibitors are discussed.

BRCA1-induced large-scale chromatin unfolding and allele-specific effects of cancer-predisposing mutations

The breast cancer susceptibility gene BRCA1 encodes a protein that has been implicated in multiple nuclear functions, including transcription and DNA repair. The multifunctional nature of BRCA1 has raised the possibility that the polypeptide may regulate various nuclear processes via a common underlying mechanism such as chromatin remodeling. However, to date, no direct evidence exists in mammalian cells for BRCA1-mediated changes in either local or large-scale chromatin structure. Here we show that targeting BRCA1 to an amplified, lac operator-containing chromosome region in the mammalian genome results in large-scale chromatin decondensation. This unfolding activity is independently conferred by three subdomains within the transactivation domain of BRCA1, namely activation domain 1, and the two BRCA1 COOH terminus (BRCT) repeats. In addition, we demonstrate a similar chromatin unfolding activity associated with the transactivation domains of E2F1 and tumor suppressor p53. However, unlike E2F1 and p53, BRCT-mediated chromatin unfolding is not accompanied by histone hyperacetylation. Cancer-predisposing mutations of BRCA1 display an allele-specific effect on chromatin unfolding: 5' mutations that result in gross truncation of the protein abolish the chromatin unfolding activity, whereas those in the 3' region of the gene markedly enhance this activity. A novel cofactor of BRCA1 (COBRA1) is recruited to the chromosome site by the first BRCT repeat of BRCA1, and is itself sufficient to induce chromatin unfolding. BRCA1 mutations that enhance chromatin unfolding also increase its affinity for, and recruitment of, COBRA1. These results indicate that reorganization of higher levels of chromatin structure is an important regulated step in BRCA1-mediated nuclear functions.

[Production of vitamin C precursor--2-keto-L-gulonic acid from D-sorbitol by mixed culture of microorganisms]

Gluconobacter oxydans SCB329 only produce a little amount of 2-Keto-L-gulonic acid(2-KLG) from D-Sorbitol when growing alone; while Gluconobacter sp. SCB110 can transform D-Sorbitol to L-Sorbose and can not produce 2-KLG. 2-Keto-L-gulonic acid, the precursor of L-Ascorbic acid (Vitamin C) synthesis, was prepared directly with a high efficiency from D-Sorbitol by mixed culture of microorganism, which comprised Gluconobacter sp. SCB110 and Gluconobacter oxydans SCB329. The fermentation product from the mixed culture broth in the D-Sorbotol-containing medium was identified as 2-Keto-L-gulonic acid by HPLC, elementary analysis and infra-red adsorption spectrum.

[Clinical evaluation on second stage reconstruction for laryngostenosis after partial laryngectomy for laryngeal cancer patients]

OBJECTIVE

To present a new method of decannulation for laryngostenosis patients after partial laryngectomy and extended partial laryngectomy, and restoration of the essential functions of larynx and normal neck appearance.

METHODS

Nineteen cases of laryngostenosis after partial laryngectomy and extended partial laryngectomy were treated with second stage reconstruction. The patients had been treated by vertical laryngectomy (6/19) using extended vertical laryngectomy (11/19) and frontolateral laryngectomy (2/19). Among these patients, second stage reconstruction of larynx was performed by using rotary door myocutaneous flap (17/19). Stemohyoideus flap (1/19) and sternocleidomastoid flap (1/19).

RESULTS

Three and five year-survival rates were 91.7% (11/12) and 3/5, respectively. Over-all decannulation rate was 84.2% (16/19), but 94.1% (16/17) in patients with rotary door myocutaneous flap and 0% (0/2) in both patients with sternohyoideus flap and sternocleidomastoid flap. There were 3 decannulation failures (15.8%). All patients resumed acceptable voice, 94.7% (18/19) enjoyed satisfactory phonation, but 5.3% (1/19) showed severe hoarseness. All except 2 patients returned normal swallow function. The latter 2 patients experienced mild abnormal swallow during eating fluid food in early stage of surgery, but had normal swallow function after 1-2 weeks.

CONCLUSION

Functional laryngectomy is a radical operation in selected cases with advanced laryngeal cancer. The second stage reconstruction with bi-pedical rotary door myocutaneous flaps can help decannulation in patients who developed laryngostenosis after partial laryngectomy and extended partial laryngectomy, and restore the essential function of larynx and normal neck appearance.

Inhibition of growth and cell cycle arrest of ARCaP human prostate cancer cells by ectopic expression of ER-alpha

The estrogen receptor-alpha (ER-alpha) is a ligand-dependent transcription factor that regulates the growth, differentiation, and development of hormone-responsive target organs. While ER-alpha has been reported to play critical role in the pathogenesis and prognosis of breast and prostate cancers, its possible functional role in regulating prostate cancer cell growth in a ligand-dependent or -independent manner is poorly understood. We addressed this question by stably transfecting wild type (wt) ER-alpha cDNA into an invasive estrogen receptor-negative human prostate cancer cell line ARCaP. We isolated several clonal lines of transfected cells expressing varying levels of ER-alpha. The ectopic expression of wt ER-a markedly inhibited the growth of ARCaP cells in vitro in an ER-a dose-dependent but ligand-independent manner. Flow cytometric analysis of the wt ER-alpha-transfected ARCaP cells revealed that wt ER-alpha expression arrested cell growth in G1 phase. Our results suggest that ER-alpha may regulate prostate cell growth and participate in the pathogenesis of prostate cancer. ER-alpha may be delivered and expressed ectopically to target prostate cancer progression.

USPIO-enhanced dynamic MRI: evaluation of normal and transplanted rat kidneys

To evaluate first-pass renal perfusion with ultrasmall superparamagnetic iron oxide (USPIO) particles by MRI, 40 normal rats (20 Dark Agouti (DA) rats and 20 Brown Norway (BN) rats) and 16 transplanted rats (12 allografts and four isografts) were studied on day 4 post-transplantation with different USPIO doses (3.0-18.1 mg Fe/kg/body weight). All animals underwent 128 consecutive snapshot fast low-angle shot (FLASH) coronal dynamic studies in 43 s. In the normal rats, a larger maximum signal decrease (MSD) in the cortex and the outer medulla is observed with an increasing dose of USPIO particles (P < 0.01). No significant differences were observed between the right and left kidneys at all doses studied. Higher MSD, time of occurrence of MSD (tMSD), and wash-in slope appear with higher doses of USPIO particles. The dynamic curves for DA rats show similar shapes when compared to those for BN rats. In the transplanted rats, allograft kidneys show lower MSD, longer tMSD, and lower wash-in slope compared to those in the normal kidneys. Isograft kidneys show perfusion patterns similar to those of normal kidneys in the cortex and the outer medulla. Histopathology indicates acute vascular rejection in all allografts and normal kidney architecture in all isografts. The results clearly show good agreement between the renal graft perfusion measurements and histopathological changes associated with rejection. This work also introduces a new signal analysis methodology for the automatic detection of transplanted organ rejection. This method compares the dynamics of the intrarenal signal intensities for native and transplanted kidneys. A quantitative measurement to detect significant differences between these signals was developed, and showed that this technique exhibits good performance in identifying renal rejection.

[Clinical application of TRAFIX internal fixation system in correction of scoliosis]

OBJECTIVE

To evaluate the results of TRAFIX internal fixation system in correction of adolescent scoliosis.

METHODS

From October 1997 to June 1999, 27 patients with idiopathic scoliosis received spinal instrumentation with TRAFIX system. Their average age was 14.2 years (from 11 to 21). Four patients of the 27 underwent anterior release, while 1 patient accepted revision approach. The average follow up time was 26 months (13-37 months).

RESULTS

The measurements for primary coronal deformity before and after surgery were 65 degrees (42 degrees-110 degrees) and 29.2 degrees (3 degrees-64 degrees) respectively. The average curve correction was 55.4%. The average fused segments were 11.5 vertebrae. The distance between the center of apex and C7 plumb line was 52.1 mm before operation (25-94 mm) and 28.5 mm after surgery (4-62 mm).

CONCLUSION

The TRAFIX internal fixation system provides three-dimensional correction with refinement, convenient and reliable fixation.

[Study of calcium buffer in SH-SY5Y cells]

AIM

To study the calcium buffer in SH-SY5Y cells.

METHODS

By using patch clamp technique, measure voltage-gated calcium currents in undifferentiated SH-SY5Y cell line. Then, by using microfluorometric technique, detect the intracellular [Ca2+]i and the dynamic recovery course after high-K+ induced [Ca2+]i elevation.

RESULTS

There are voltage-gated calcium currents in undifferentiated SH-SYSY cell line. When the time intervals between the stimulus are < 150s, the recovery course will be much more deferred because of the saturation of the intracellular calcium buffer; and when the intervals between the stimulus are > 150 s, the buffer will recruit so as to lead to the steadiness state of the recover course.

CONCLUSION

Calcium buffer proteins have an important effect in the course of cellular calcium signal transduction.

Hydrophilic, pro-drug analogues of T138067 are efficacious in controlling tumor growth in vivo and show a decreased ability to cross the blood brain barrier

The novel anticancer compound T138067 is an irreversible inhibitor of tubulin polymerization. Amides 3-6 were synthesized using standard methodologies and determined to be significantly less lipophilic than T138067 based on logP calculations. Tubulin polymerization and [(3)H]-T138067 competition assays revealed that these amides are pro-drugs for parent aniline 2. Amides 3-5 showed no detectable signs of crossing the blood brain barrier, while amide 6 was found in extremely small amounts (12 ng/g of brain tissue). Aniline 2, which was formed in vivo from these amides, was found in significantly smaller amounts (approximately 20 to >5000 times) in the brain than when 2 was administered directly. The in vivo efficacy of amide 6 approached that of T138067 and was better tolerated when administered to athymic nude mice bearing MX-1 human mammary tumor xenografts.

High-resolution crystal structure of apolipoprotein(a) kringle IV type 7: insights into ligand binding

Apolipoprotein(a) [apo(a)] consists of a series of tandemly repeated modules known as kringles that are commonly found in many proteins involved in the fibrinolytic and coagulation cascades, such as plasminogen and thrombin, respectively. Specifically, apo(a) contains multiple tandem repeats of domains similar to plasminogen kringle IV (designated as KIV(1) to KIV(10)) followed by sequences similar to the kringle V and protease domains of plasminogen. The KIV domains of apo(a) differ with respect to their ability to bind lysine or lysine analogs. KIV(10) represents the high-affinity lysine-binding site (LBS) of apo(a); a weak LBS is predicted in each of KIV(5)-KIV(8) and has been directly demonstrated in KIV(7). The present study describes the first crystal structure of apo(a) KIV(7), refined to a resolution of 1.45 A, representing the highest resolution for a kringle structure determined to date. A critical substitution of Tyr-62 in KIV(7) for the corresponding Phe-62 residue in KIV(10), in conjunction with the presence of Arg-35 in KIV(7), results in the formation of a unique network of hydrogen bonds and electrostatic interactions between key LBS residues (Arg-35, Tyr-62, Asp-54) and a peripheral tyrosine residue (Tyr-40). These interactions restrain the flexibility of key LBS residues (Arg-35, Asp-54) and, in turn, reduce their adaptability in accommodating lysine and its analogs. Steric hindrance involving Tyr-62, as well as the elimination of critical ligand-stabilizing interactions within the LBS are also consequences of this interaction network. Thus, these subtle yet critical structural features are responsible for the weak lysine-binding affinity exhibited by KIV(7) relative to that of KIV(10).

Three new sesquiterpene glycosides from Dendrobium nobile with immunomodulatory activity

Dendroside A (1) and dendronobilosides A and B (2 and 3), three new sesquiterpene glycosides, have been isolated from the stems of Dendrobium nobile, a plant used in Chinese traditional medicine. Their structures and stereochemistry were determined as 10beta,12,14-trihydroxyalloaromadendrane 14-O-beta-D-glucopyranoside (1), 10,12-dihydroxypicrotoxane 10,12-di-O-beta-D-glucopyranoside (2), and 6alpha,10,12-trihydroxypicrotoxane 10-O-beta-D-glucopyranoside (3), respectively, on the basis of spectroscopic and chemical methods. Quantum chemistry calculations were used in support of the structural determination of 1. Compounds 1 and 2 were found to stimulate the proliferation of murine T and B lymphocytes in vitro, while compound 3 showed inhibitory activity in this same assay.

[Degradation of nitrobenzene in water by electrohydrodynamic DC discharge]

In this paper, the experimental results with respect to the degradation of nitrobenzene in water using electrohydrodynamic DC discharge were presented. The DC voltage was 40 kV, the degradation efficiency in the first discharge process reached 50%, the total degradation efficiency in the second discharge process reached 80%. The products contained acetone. At the same time, the degradation efficiency variation with the voltage polarity, flux, and concentration were studied. These studies will be helpful to the treatment of organic wastewater.

Crystal structure of an aldehyde reductase Y50F mutant-NADP complex and its implications for substrate binding

Pig aldehyde reductase containing the active site mutation tyrosine(50) to phenylalanine has been crystallized in the presence of the cofactor NADP(H) to a resolution of 2.2 A. This structure clearly shows loss of the tyrosine hydroxyl group and no other significant perturbations compared with previously determined structures. The mutant binds cofactor (both oxidized and reduced) more tightly than the wild-type enzyme but shows a complete lack of binding of the aldehyde reductase inhibitor barbitone, as determined by fluorescence titrations. Numerous attempts at preparing a ternary complex with a range of small aldehyde substrates were unsuccessful. This result, in addition to the inability of the mutant protein to bind the inhibitor, provides strong evidence for the proposal that the tyrosine hydroxyl group is essential for substrate binding in addition to catalysis.

Functional polymer affinity matrix for purifying hexahistidine-tagged recombinant protein

A functional polyacrylic acid (PAA) adsorbent has been prepared for metal chelate affinity chromatography. It has been found to chelate nickel ion Ni2+ strongly, and was evaluated for the ability to bind proteins containing neighbouring histidine residues. The principle of the technique was illustrated with Aeromonas hydrophila outer membrane protein OmpTS. DNA elements coding for adjacent histidines were fused to the Aeromonas hydrophila ompTS gene. Subsequent expression in E. coli resulted in the production of hybrid protein His6-OmpTS that could be purified by Ni2+-PAA affinity chromatography. The remarkable specificity found makes it an attractive addition to the range of adsorbents for metal chelate affinity chromatography.

Calmodulin protects cells from death under normal growth conditions and mitogenic starvation but plays a mediating role in cell death upon B-cell receptor stimulation

Calmodulin (CaM) is the main intracellular Ca2+ sensor protein responsible for mediating Ca2+ triggered processes. Chicken DT40 lymphoma B cells express CaM from the two genes, CaMI and CaMII. Here we report the phenotypes of DT40 cells with the CaMII gene knocked out. The disruption of the CaMII gene causes the intracellular CaM level to decrease by 60%. CaMII-/- cells grow more slowly and die more frequently as compared to wild type (wt) cells but do not exhibit significant differences in their cell cycle profile. Both phenotypes are more pronounced at reduced serum concentrations. Upon stimulation of the B-cell receptor (BCR), the resting Ca2+ levels remain elevated after the initial transient in CaMII-/- cells. Despite higher Ca2+ resting levels, the CaMII-/- cells are partially protected from BCR induced apoptosis indicating that CaM plays a dual role in apoptotic processes.

The distraction reduction fixation system and its application in spondylolisthesis

OBJECTIVE

An internal fixation apparatus--distraction reduction fixation system (DRFS) was designed to satisfy the clinical needs for spondylolisthesis.

METHODS

Since 1996, 53 patients were treated with DRFS. Among them, 35 had spondylolisthesis, 12 had lumbar canal stenosis accompanied with instability, 2 had vertebral tumors and 4 suffered from spinal fracture. The average age was 53.6 years old (ranged 24 approximately 72 yrs). The mean time for follow-up was 30.6 months (16 approximately 44 months).

RESULTS

The slip rate was 0.15 +/- 0.10 before operation, and decreased to 0.09 +/- 0.07 after operation. Entire slip reposition was achieved in 19 cases (54.3%). The change in height of the intervertebral space within the fixation segments was 0.7 +/- 0.17.

CONCLUSION

DRFS achieved better results for spondylolisthesis less II degree and no other adverse effects were found. Compared with other foreign and domestic techniques, it had advantages in less implants, less operation gears required and ease to utilize in operation. It was proved to be an ideal internal fixation apparatus.

[A clinical evaluation on reconstruction in extended partial laryngectomy for transglottic cancer]

OBJECTIVE

Transglottic cancer has been a definite indication for total laryngectomy in decades, compromising function of the larynx. The purpose of this study is to present a new radical surgery of extended partial laryngectomy and reconstruction to restore the essential function of larynx.

METHODS

Forty-one cases of transglottic cancer were treated by extended vertical laryngectomy (26/41), extended frontolateral laryngectomy (5/41) and subtotal laryngectomy (10/41); the defects of larynx were reconstructed by rotary door myocutaneous flap in twenty-seven cases, by sternohyoideus flap in seven cases, by osteomuscular flap in five cases and by sternocleidomastoid flap in two cases.

RESULTS

The 3 and 5 year survival rates were 85.7% (30/35) and 74.1% (20/27) respectively, those for stage III were 84.6% (22/26) and 76.2% (16/21), for stage IV were 3/4 and 1/2 respectively. All cases resumed acceptable voice, 92.7% (38/41) and enjoyed satisfactory phonation. The over-all decannulation rate was 87.8% (36/41), those with rotary door myocutaneous flap was 96.3% (26/27), with sternohyoideus flap was 5/7, with osteomuscular flap was 4/5 and with sternocleidomastoid flap was 1/2. All patients had normal swallow function.

CONCLUSION

Extended partial laryngectomy is a kind of radical operation in selected cases of transglottic cancer. The method of reconstruction with rotary door myocutaneous flap can improve curative effect and the essential functions of the larynx.

[Different sampling method affects the voice assessment results for the patient with vocal polyp]

OBJECTIVE

In order to definitude the influence caused by the different sampling in voice assessment.

METHOD

We comparing the results acquired by total section and subsection sampling.

RESULT

The results acquired by subsection tended to normal more than those acquired by total section.

CONCLUSION

Subsection sampling voice assessment might conceal the degree of the disease state of patients.

Histological reaction to hydroxyapatite in the middle ear of rats

OBJECTIVE

Present study was performed to evaluate the histological response of rat middle ear mucosa following implantation of Apaceram granules, a synthetic dense hydroxyapatite [Ca10(PO4)6(OH)2], prepared from commercially available synthetic auditory ossicle, and to assess the precise histological response of the rat middle ear to implantation of Apaceram granules, by microscopic examination of mucosal tissue at various time points after implantation.

METHODS

Apaceram granules were implanted in the temporal bulla of 32 rats. As control, sham surgery was performed in a group of ten rats. Bulla specimens were removed at 1, 3, 7, 14, and 30 days after surgery in the implant and control groups, and at 90, 180 and 300 days in the implant group. Specimens were decalcified, sectioned at a thickness of 6 microm, and stained with haematoxylin and eosin, and Mallory's azan for histological examination of mucosal tissue.

RESULTS

Evidence of inflammatory reaction was slightly greater in the implant group than in controls. Lymphocyte and macrophage counts were higher in the implant group 1 day after surgery, but decreased to similar levels by day 3, and continued to decrease thereafter, and few were observed in the implant group at 300 days. Neutrophils observed at 1 day after surgery were not evident in either group at 3 days. Gradual fibrosis development continued in both groups over all time points studied. Foreign body giant cells were never observed in either group. No bony reaction was observed in any specimen.

CONCLUSION

The results of this study suggest that Apaceram is biocompatible and suitable for reconstructive ear surgery.

[Screening and characteristics of mutants of E. coli resistant to acetate inhibition]

Acetate is accumulated in the aerobic high cell density culture of Escherichia coli, Which seriously inhibits cell growth and expression of recombinant proteins. To alleviate acetate inhibition, mutants of E. coli JM101 were generated by 60Co radiation and then enriched in continuous culture with acetate as the selective pressure. One of the mutants isolated, JL3, showed obvious increased tolerance toward acetate and maintained phenotypic stability on slant without acetate. In MA medium containing 10 g/L of sodium acetate, the specific growth rate and the glucose consumption rate of JL3 were higher than those of JM101.

[Impact of substrate salinity on caloric value, energy accumulation and its distribution in various organs of Bruguiera gymnorrhiza seedlings]

The study with artificial culture showed that the accumulation of dry matter and energy in Bruguiera gymnorrhiza seedlings was promoted by low substrate salinity, but inhibited by high substrate salinity, which peaked at 10 mg.g-1 substrate salinity. With the increase of substrate salinity, the dry matter and the energy tended to be allocated to the micro-roots and leaves, which are nutrient-absorbing organ and photosynthetic organ, respectively. With the increase of substrate salinity, the changes in caloric values were differed in various organs of B. gymnorrhiza seedlings, and those in leaves could reflect the changes in the salt-resistance of the seedlings.

The crystal structure of an aldehyde reductase Y50F mutant-NADP complex and its implications for substrate binding

In order to understand more fully the structural features of aldo-keto reductases (AKRs) that determine their substrate specificities it would be desirable to obtain crystal structures of an AKR with a substrate at the active site. Unfortunately the reaction mechanism does not allow a binary complex between enzyme and substrate and to date ternary complexes of enzyme, NADP(H) and substrate or product have not been achieved. Previous crystal structures, in conjunction with numerous kinetic and theoretical analyses, have led to the general acceptance of the active site tyrosine as the general acid-base catalytic residue in the enzyme. This view is supported by the generation of an enzymatically inactive site-directed mutant (tyrosine-48 to phenylalanine) in human aldose reductase [AKR1B1]. However, crystallization of this mutant was unsuccessful. We have attempted to generate a trapped cofactor/substrate complex in pig aldehyde reductase [AKR1A2] using a tyrosine 50 to phenylalanine site-directed mutant. We have been successful in the generation of the first high resolution binary AKR-Y50F:NADP(H) crystal structure, but we were unable to generate any ternary complexes. The binary complex was refined to 2.2A and shows a clear lack of density due to the missing hydroxyl group. Other residues in the active site are not significantly perturbed when compared to other available reductase structures. The mutant binds cofactor (both oxidized and reduced) more tightly but shows a complete lack of binding of the aldehyde reductase inhibitor barbitone as determined by fluorescence titrations. Attempts at substrate addition to the active site, either by cocrystallization or by soaking, were all unsuccessful using pyridine-3-aldehyde, 4-carboxybenzaldehyde, succinic semialdehyde, methylglyoxal, and other substrates. The lack of ternary complex formation, combined with the significant differences in the binding of barbitone provides some experimental proof of the proposal that the hydroxyl group on the active site tyrosine is essential for substrate binding in addition to its major role in catalysis. We propose that the initial event in catalysis is the binding of the oxygen moiety of the carbonyl-group of the substrate through hydrogen bonding to the tyrosine hydroxyl group.

Rotating electrode potentiometry: lowering the detection limits of nonequilibrium polyion-sensitive membrane electrodes

A rotating electrode configuration is evaluated as a means to lower the detection limits of newly devised polyion-sensitive membrane electrodes (PSEs). Planar potentiometric polycation and polyanion PSEs are prepared by incorporating tridodecylmethylammonium chloride and calcium dinonylnaphthalenesulfonate, respectively, into plasticized PVC or polyurethane membranes and mounting disks of such films on an electrode body housed in a conventional rotating disk electrode apparatus. Rotation of the PSEs at 5000 rpm results in an enhancement in the detection limits toward heparin (polyanion) and protamine (polycation) of at least 1 order of magnitude (to 0.01 unit/mL for heparin; 0.02 microg/mL for protamine) over that observed when the EMF responses of the same electrodes are assessed using a stir-bar to achieve convective mass transport. A linear relationship between omega(-1/2), where omega is the rotating angular frequency, and C1/2, the polyion concentration corresponding to half the total maximum deltaEMF response toward the polyion species, is observed. It is further shown that the rotating polycation sensor can be used as an end-point detector to greatly enhance (relative to nonrotated indicator electrode) the analytical resolution and precision for measurement of low concentrations of heparin when such samples are titrated with protamine. The theoretical basis for lowering the detection limits by rotating PSEs is discussed based on the unique nonequilibrium response mechanism of such sensors.

Characterization of a novel trans-activation domain of BRCA1 that functions in concert with the BRCA1 C-terminal (BRCT) domain

Mutations in the breast cancer susceptibility gene, BRCA1, account for a significant proportion of hereditary breast and ovarian cancers. The BRCA1 C-terminal (BRCT) domain, which can activate transcription when fused to a heterologous DNA binding domain, is required for BRCA1 function in suppression of tumorigenesis. Here, we provide evidence for a new activation domain in BRCA1 that lies adjacent to the BRCT domain. We name the two domains AD1 and AD2, respectively. Like AD2, the newly discovered AD1 can act independently as an activation domain in both yeast and human cells. However, unlike AD2, AD1 activity in mammalian cells is cell type context-dependent. Furthermore, combination of these two domains in mammalian cells can result in a robust synergy in transcriptional activation. A highly conserved coiled-coil motif in AD1 is required for the cooperative transcription activation. Interestingly, the functional cooperativity between AD1 and AD2 is absent in certain breast and ovarian cancer cell lines, although each domain can still activate transcription. Therefore, the differential and cooperative actions of the two activation modules may contribute to the heterogeneous risk of BRCA1 mutations in different tissues.

Immunomodulation for intestinal transplantation by allograft irradiation, adjunct donor bone marrow infusion, or both

BACKGROUND

The passenger leukocytes in the intestine have a lineage profile that predisposes to graft-versus-host disease (GVHD) in some animal models and have inferior tolerogenic qualities compared with the leukocytes in the liver, other solid organs, and bone marrow. Elimination by ex vivo irradiation of mature lymphoid elements from the bowel allografts is known to eliminate the GVHD risk. We hypothesized that infusion of donor bone marrow cells (BMC) in recipients of irradiated intestine would improve tolerogenesis without increasing the risk of GVHD.

METHODS

Orthotopic small intestine transplantation was performed with the GVHD-prone Lewis (LEW)-to-Brown Norway (BN) combination and the reverse GVHD-resistant BN-to-LEW model under a short course of tacrolimus treatment (1 mg/kg/day, days 0-13, 20, 27). Grafts were irradiated ex vivo, using a 137Cs source. In selected experimental groups, donor BMC (2.5 x 10(8)) were infused on the day of small intestine transplantation.

RESULTS

The unmodified LEW intestine remained intact, whether transplanted alone or with adjunct donor BMC infusion, but all of the BN recipients died of GVHD after approximately 2 months. Intestinal graft irradiation (10 Gy) effectively prevented the GVHD and prolonged survival to 92.5 days, but all of the BN recipients died with chronic rejection of the LEW grafts, which was prevented by infusion of adjunct donor BMC without causing GVHD. In the GVHD-resistant reverse strain direction (BN-->LEW), all intestinal recipients treated for 27 days with tacrolimus survived > or =150 days without regard for graft irradiation or adjunct BMC, but chronic rejection was severe in the irradiated intestine, moderate in the unaltered graft, and least in the irradiated intestine transplanted with adjunct BMC. Mild arteritis in the 150 day allografts of both strain combinations (i.e., LEW--> BN and BN-->LEW) may have been irradiation associated, but this was prevented when weekly doses of tacrolimus were continued for the duration of the experiment rather than being stopped at 27 days.

CONCLUSIONS

Recipients are protected from GVHD by irradiating intestinal allografts, but the resulting leukocyte depletion leads to chronic rejection of the transplanted bowel. The chronic rejection is prevented with adjunct donor BMC without causing GVHD. Although application of the strategy may be limited by the possibility of radiation injury, the results are consistent with the paradigm that we have proposed to explain organ-induced graft acceptance, tolerance, and chronic rejection.

[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.