Non-viral-mediated gene therapy approaches for bone repair

OBJECTIVES

Bone repair strategies continue to be developed for alternatives to autografting, allogeneic implants of banked bone, and other bone substitutes. Efforts have included the delivery of potent growth and/or differentiation factors and the use of gene therapy. For bone regeneration, gene therapy is the delivery, uptake and expression of DNA that has been localized to a wound bed. The objective of the current study is to investigate methods to enhance non-viral-mediated means of gene uptake and expression for use in bone regeneration.

METHODS

Several types of DNA-polymer complexes, either applied directly to baby hamster kidney (BHK) cells, or released from a porous, resorbable gene-activated matrix (GAM), were evaluated in vitro for their ability to transfect cells with a circular plasmid DNA construct expressing green fluorescent protein. Complexes included conjugates containing a lipophilic reagent, liposomes, poly-ethyl-oxazoline, and poly-ethyleneimine (PEI). Data were subjected to analysis of variance and Fisher's protected least significant difference for multiple comparisons with significance established at p < 0.05.

RESULTS

Transfection efficiencies of the liposome and PEI complexes improved in vitro when released from resorbable GAMs. The lipophilic reagent FuGene 6 demonstrated abundant uptake and expression in the initial 1- and 2-day evaluation periods. In contrast, the DNA-liposome and PEI GAM complexes demonstrated a sustained release, uptake and expression by the BHK cells at the 2-, 4-, and 7-day, and 4- and 7-day evaluation intervals, respectively.

CONCLUSION

GAM technology appears to improve the functional stability and release duration of incorporated DNA-polymer complexes in the present in vitro studies. The ongoing objective of our research is to develop a localized treatment to improve the uptake and expression of plasmid DNA by non-viral-mediated gene therapy.

N-acetylcysteine enhances muscle cysteine and glutathione availability and attenuates fatigue during prolonged exercise in endurance-trained individuals

The production of reactive oxygen species in skeletal muscle is linked with muscle fatigue. This study investigated the effects of the antioxidant compound N-acetylcysteine (NAC) on muscle cysteine, cystine, and glutathione and on time to fatigue during prolonged, submaximal exercise in endurance athletes. Eight men completed a double-blind, crossover study, receiving NAC or placebo before and during cycling for 45 min at 71% peak oxygen consumption (VO2 peak) and then to fatigue at 92% VO2 peak. NAC was intravenously infused at 125 mg.kg(-1).h(-1) for 15 min and then at 25 mg.kg(-1).h(-1) for 20 min before and throughout exercise. Arterialized venous blood was analyzed for NAC, glutathione status, and cysteine concentration. A vastus lateralis biopsy was taken preinfusion, at 45 min of exercise, and at fatigue and was analyzed for NAC, total glutathione (TGSH), reduced glutathione (GSH), cysteine, and cystine. Time to fatigue at 92% VO2 peak was reproducible in preliminary trials (coefficient of variation 5.6 +/- 0.6%) and with NAC was enhanced by 26.3 +/- 9.1% (NAC 6.4 +/- 0.6 min vs. Con 5.3 +/- 0.7 min; P <0.05). NAC increased muscle total and reduced NAC at both 45 min and fatigue (P <0.005). Muscle cysteine and cystine were unchanged during Con, but were elevated above preinfusion levels with NAC (P <0.001). Muscle TGSH (P <0.05) declined and muscle GSH tended to decline (P=0.06) during exercise. Both were greater with NAC (P <0.05). Neither exercise nor NAC affected whole blood TGSH. Whereas blood GSH was decreased and calculated oxidized glutathione increased with exercise (P <0.05), both were unaffected by NAC. In conclusion, NAC improved performance in well-trained individuals, with enhanced muscle cysteine and GSH availability a likely mechanism.

[Sequencing of cytochrome C oxidase 1 gene of Ancylostoma duodenale and Necator americanus]

AIM

To identify the genetic diversity between Ancylostoma duodenale and Necator americanus.

METHODS

Mitochondrial cytochrome C oxidase subunit 1 (CO1) gene was amplified from genomic DNA of human hookworms collected from infected patients in Hejiang County, Sichuan Province, and the purified PCR products were directly sequenced by using Licor auto-sequencer.

RESULTS

The PCR products were about 700 bp. Alignment of CO1 gene fragment sequences showed 89.7% similarity between Ancylostoma duodenale and Necator americanus, but still certain nucleotide variations (10.3%) existed.

CONCLUSION

CO1 gene sequence can be used as a marker to identify the two species of human hookworms.

Stroke therapy in traditional Chinese medicine (TCM): prospects for drug discovery and development

Brain injuries resulting from stroke are a major and increasing public health problem in both developed and developing countries worldwide. China's extensive experience in the use of traditional Chinese medicines (TCMs) in stroke therapy indicates that TCM preparations are effective, with few or no side-effects. There are more than 100 traditional medicines in use for stroke therapy in China. Some of their therapeutic effects in stroke have been confirmed by recent clinical studies. A large number of compounds have been isolated from TCMs and most of these resources have not yet been characterized for pharmacological purposes. Here, this article explains how TCM provides an extensive and knowledge-rich foundation for implementing a strategically focused pharmacological research program aimed at the development of new drugs.

Distinct regulatory properties of pyruvate dehydrogenase kinase and phosphatase isoforms

The mammalian pyruvate dehydrogenase complex (PDC) plays central and strategic roles in the control of the use of glucose-linked substrates as sources of oxidative energy or as precursors in the biosynthesis of fatty acids. The activity of this mitochondrial complex is regulated by the continuous operation of competing pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP) reactions. The resulting interconversion cycle determines the fraction of active (nonphosphorylated) pyruvate dehydrogenase (E1) component. Tissue-specific and metabolic state-specific control is achieved by the selective expression and distinct regulatory properties of at least four PDK isozymes and two PDP isozymes. The PDK isoforms are members of a family of serine kinases that are not structurally related to cytoplasmic Ser/Thr/Tyr kinases. The catalytic subunits of the PDP isoforms are Mg2+-dependent members of the phosphatase 2C family that has binuclear metal-binding sites within the active site. The dihydrolipoyl acetyltransferase (E2) and the dihydrolipoyl dehydrogenase-binding protein (E3BP) are multidomain proteins that form the oligomeric core of the complex. One or more of their three lipoyl domains (two in E2) selectively bind each PDK and PDP1. These adaptive interactions predominantly influence the catalytic efficiencies and effector control of these regulatory enzymes. When fatty acids are the preferred source of acetyl-CoA and NADH, feedback inactivation of PDC is accomplished by the activity of certain kinase isoforms being stimulated upon preferentially binding a lipoyl domain containing a reductively acetylated lipoyl group. PDC activity is increased in Ca2+-sensitive tissues by elevating PDP1 activity via the Ca2+-dependent binding of PDP1 to a lipoyl domain of E2. During starvation, the irrecoverable loss of glucose carbons is restricted by minimizing PDC activity due to high kinase activity that results from the overexpression of specific kinase isoforms. Overexpression of the same PDK isoforms deleteriously hinders glucose consumption in unregulated diabetes.

Ubiquitin-activating enzyme (E1) isoforms in lens epithelial cells: origin of translation, E2 specificity and cellular localization determined with novel site-specific antibodies

Lens development and response to peroxide stress are associated with dramatic changes in protein ubiquitination, reflecting dynamic changes in activity of the ubiquitin-activating enzyme (E1). Two isoforms of E1 (E1A and E1B) have been identified in lens cells although only one E1 mRNA, containing three potential translational start sites, has been detected. Novel, site-specific antibodies to E1 were generated and the hypothesis that the two isoforms of E1 are translated from alternative initiation codons of a single mRNA was tested. Antibodies raised against E1A-N peptide (Met(1)to Cys(23)of E1A) reacted only with E1A by immunoblot and immunoprecipitation. Antibodies raised against E1B-N peptide (Met(1)to Glu(25)of E1B or Met(41)to Glu(65)of E1A) and E1AB-C peptide (His(1030)to Arg(1058)of E1A or His(990)to Arg(1018)of E1B) reacted with both E1A and E1B. These results indicate that (1) E1A and E1B contain the same C-terminal residues; (2) E1A contains the N terminal sequence of E1B; and (3) E1B does not contain the N terminal sequence of E1A. The two isoforms of lens E1 are therefore translated from a single mRNA. Specifically, E1A is translated from the first initiation codon, and E1B translated from the second initiation codon. E1A and E1B were affinity-purified, and their ability to 'charge' ubiquitin carrier proteins (E2s) with activated ubiquitin was compared in a cell-free system. E1A and E1B were indistinguishable with respect to charging different E2s. However, E1 immunolocalization studies with human lens epithelial cells indicate that E1A and E1B are preferentially localized to the nucleus and cytosol, respectively. This observation suggests that E1A and E1B ubiquitinate different proteins and serve different functions in intact cells.

[Treatment of 2-naphtholwastewater using air oxidation and ion exchange]

The properties of 2-naphtholwastewater were studied in details in this paper, the wastewater was characterized by the strong acidity, high buffer capability and concentrated salt. Air oxidation and anion exchange were employed for the treatment of the wastewater. Under formal pH, room temperature and 1 BV/h rate, the result showed that the removal of COD reached to 97% and the recovery of sodium naphthalensulfonate to 98%. Besides, wastewater treated can be reused for washing the sodium naphthalensulfonate.

Signal-transducing function of Na+-K+-ATPase is essential for ouabain's effect on [Ca2+]i in rat cardiac myocytes

We showed before that Na+-K+-ATPase is also a signal transducer in neonatal rat cardiac myocytes. Binding of ouabain to the enzyme activates multiple signal pathways that regulate cell growth. The aims of this work were to extend such studies to adult cardiac myocytes and to determine whether the signal-transducing function of Na+/K+-ATPase regulates the well-known effects of ouabain on intracellular Ca2+ concentration ([Ca2+]i). In adult myocytes, ouabain activated protein tyrosine phosphorylation and p42/44 mitogen-activated protein kinases (MAPKs), increased production of reactive oxygen species (ROS), and raised both systolic and diastolic [Ca2+]i. Pretreatment of myocytes with several Src kinase inhibitors, or overexpression of a dominant negative Ras, antagonized ouabain-induced activation of MAPKs and increases in [Ca2+]i. Treatment with PD-98059 (a MAPK kinase inhibitor) or overexpression of a dominant negative MAPK kinase 1 also ablated the effect of ouabain on MAPKs and [Ca2+]i. N-acetyl-cysteine, which blocks the effect of ouabain on ROS, did not prevent the ouabain-induced rise in [Ca2+]i. Clearly, the activation of the Ras/MAPK cascade, but not ROS generation, is necessary for ouabain-induced increases in [Ca2+]i in rat cardiac myocytes.

The role of ruthenium and rhenium diimine complexes in conjugated polymers that exhibit interesting opto-electronic properties

This paper reports the synthesis and opto-electronic properties of different conjugated polymers that contain the diimine complexes of ruthenium or rhenium. Conjugated poly(phenylene vinylene)s that contain aromatic 1,3,4-oxadiazole and 2,2'-bipyridine units on the main chain were synthesized by the palladium catalyzed olefinic coupling reaction. Other types of polymers based on 1,10-phenanthroline bis(2,2-bipyridyl) ruthenium(II) or chlorotricarbonyl rhenium(I) complexes were also synthesized by the same reaction. In general, these polymers exhibit two absorption bands due to the pi - pi transition of the conjugated main chain and the d-pi* metal-to-ligand charge-transfer transition of the metal complex. As a result, the photosensitivity of the polymers beyond 500 nm was enhanced. Charge-carrier mobility measurements showed that the presence of metal complexes could facilitate the charge-transport process, and the enhancement in carrier mobility was dependent on the metal content in the polymer. In addition, we have also demonstrated that the ruthenium complex could act as both photosensitizer and light emitter. Photovoltaic cells were constructed, and they were subjected to irradiation with a xenon arc lamp. Under illumination, the short circuit current and the open circuit voltage were measured to be 0.05 mAcm(-2) and 0.35 V, respectively. The polymers were fabricated into single-layer emitting devices, and light emission was observed when the device was subjected to forward bias. The maximum luminance was determined to be 300 cdm(-2), and the external quantum efficiency was approximately 0.05 to 0.2%. Although the efficiency was relatively low when compared with other devices based on organic materials, we have demonstrated the first examples of using transition metal complexes for both photovoltaic and light-emitting applications.

A mutant plasma membrane ATPase, Pma1-10, is defective in stability at the yeast cell surface

Pma1 is a plasma membrane H(+)-ATPase whose activity at the cell surface is essential for cell viability. In this paper we describe a temperature-sensitive pma1 allele, pma1-10 (with two point mutations in the first cytoplasmic loop of Pma1), in which the newly synthesized mutant protein fails to remain stable at the cell surface at 37 degrees C. Instead, Pma1-10 appears to undergo internalization for vacuolar degradation in a manner dependent on End4, Vps27, Doa4, and Pep4. By contrast with wild-type Pma1, mutant Pma1-10 is hypophosphorylated and fails to associate with a Triton-insoluble fraction at 37 degrees C, suggesting failure to enter lipid rafts. Kinetic analysis reveals that, at the permissive temperature, newly synthesized Pma1-10 acquires Triton-insolubility before becoming stabilized. We suggest that phosphorylation and lipid raft association may play important roles in maintaining protein stability at the plasma membrane.

Acoustic nonlinearity parameter tomography for biological tissues via parametric array from a circular piston source--theoretical analysis and computer simulations

The acoustic nonlinearity parameter B/A describes the nonlinear features of a medium and may become a novel parameter for ultrasonic tissue characterization. This paper presents a theoretical analysis for acoustic nonlinear parameter tomography via a parametric array. As two primary waves of different frequencies are radiated simultaneously from a circular piston source, a secondary wave at the difference frequency is generated due to the nonlinear interaction of the primary waves. The axial and radial distributions of sound pressure amplitude for the generated difference frequency wave in the near field are calculated by a superposition of Gaussian beams. The calculated results indicated that the difference frequency component of the parametric array grows linearly with distance from the piston source. It therefore provides a better source to do the acoustic nonlinearity parameter tomography because the fundamental and second harmonic signals both have a near field that goes through many oscillations due to diffraction. By using a finite-amplitude insert substitution method and a filtered convolution algorithm, a computer simulation for B/A tomography from the calculated sound pressure of the difference frequency wave is studied. For biological tissues, the sound attenuation is considered and compensated in the image reconstruction. Nonlinear parameter computed tomography (CT) images for several biological sample models are obtained with quite good quality in this study.

Development of cataractous macrophthalmia in mice expressing an active MEK1 in the lens

PURPOSE

To characterize the extracellular signal-regulated kinase (ERK) pathway in the lens and to try to understand how this pathway contributes to lens function and cataractogenesis.

METHODS

The members of the ERK pathway in the lens were examined by Western blotting, immunohistochemical staining, and kinase assay. A gain-of-function approach was used to perturb the ERK pathway in the lenses of transgenic mice via expression of a constitutively active mutant of the mitogen-activated protein kinase kinase 1 (MEK1(E)), the direct upstream kinase of the ERK1 and ERK2 kinases, under the alphaA-crystallin promoter.

RESULTS

The presence of an active ERK pathway was found in lens epithelial cells and in differentiating fibers. Transgenic mice that expressed MEK1(E) developed postnatal cataracts as well as macrophthalmia. Distinct morphologic alterations, such as lens enlargement, swelling fiber cells, enlarged extracellular space, and vacuole formation, were observed in the lenses of these transgenic mice. A significant increase in the glucose transporter 1 (GLUT1) level, as well as in the glucose level, was detected in the lens.

CONCLUSIONS

The MAP kinase pathway is involved in the regulation of glucose metabolism and balance in the mouse lens. Moreover, the alteration of MAP kinase activity in the lens is sufficient to cause cataract formation with enlarged extracellular space and vacuoles in the differentiating fibers. This transgenic mouse may provide a useful model for understanding the mechanism(s) for some aspects of human cataracts.

Reaction Mechanism for Mammalian Pyruvate Dehydrogenase Using Natural Lipoyl Domain Substrates

The pyruvate dehydrogenase (E1) component of the pyruvate dehydrogenase complex (PDC) catalyzes a two-step reaction. Recombinant production of substrate amounts of the lipoyl domains of the dihydrolipoyl transacetylase (E2) component of the mammalian PDC allowed kinetic characterization of the rapid physiological reaction catalyzed by E1. Using either the N-terminal (L1) or the internal (L2) lipoyl domain of E2 as a substrate, analyses of steady state kinetic data support a ping pong mechanism. Using standard E1 preparations, Michaelis constants (Km) were 52 +/- 14 microM for L1 and 24.8 +/- 3.8 microM for pyruvate and k(cat) was 26.3 s(-1). With less common, higher activity preparations of E1, the Km values were > or =160 microM for L1 and > or =35 microM for pyruvate and k(cat) was > or =70 s(-1). Similar results were found with the L2 domain. The best synthetic lipoylated-peptide (L2 residues 163-177) was a much poorer substrate (Km > or =15 mM, k(cat) approximately equals 5 s(-1); k(cat)/Km decreased >1,500-fold) than L1 or L2, but a far better substrate in the E1 reaction than free lipoamide (k(cat)/Km increased >500-fold). Each lipoate source was an effective substrate in the dihydrolipoyl dehydrogenase (E3) reaction, but E3 had a lower Km for the L2 domain than for lipoamide or the lipoylated peptides. In contrast to measurements with slow E1 model reactions that use artificial acceptors, we confirmed that the natural E1 reaction, using lipoyl domain acceptors, was completely inhibited (>99%) by phosphorylation of E1 and the phosphorylation strongly inhibited the reverse of the second step catalyzed by E1. The mechanisms by which phosphorylation interferes with E1 activity is interpreted based on accrued results and the location of phosphorylation sites mapped onto the 3-D structure of related alpha-keto acid dehydrogenases.

DNA-PKcs is required for activation of innate immunity by immunostimulatory DNA

Bacterial DNA and related synthetic immunostimulatory oligodeoxyribonucleotides (ISS-ODN) stimulate innate immunity. However, the molecular recognition mechanism that initiates signaling in response to bacterial DNA and ISS-ODN has not been identified. Herein, we demonstrate that administration of bacterial DNA and ISS-ODN to mice lacking the catalytic subunit of DNA-PK (DNA-PKcs) and in vitro stimulation of BMDM from these mice result in defective induction of IL-6 and IL-12. Further analysis using BMDM of IKKbeta(-/-) revealed that both DNA-PKcs and IKKbeta are essential for normal cytokine production in response to ISS-ODN or bacterial DNA. ISS-ODN and bacterial DNA activate DNA-PK, which in turn contributes to activation of IKK and NF-kappaB. These results reveal a novel role of DNA-PKcs in innate immune responses and a link between DNA repair and innate immunity.

[The analysis of the axises of corneal astigmatism and total astigmatism in astigmatic patients]

PURPOSE

The axial amount and the relationship between the axises of corneal astigmatism and total astigmatism were statistically analyzed in ametropic patients, for the purpose of selecting the refractive correction, the base curve of contact lens, the axis of astigmatic contact lens, and providing the reference of operational amount of ecimer laser keratoplasty.

METHODS

The refractive state and the corneal curvature of ametropic patients were measured and consecutvely repeated 3 times in the same eye at the same state with the same autorefractometer in 107 cases. The detected axises of total astigmatism and corneal astigmatism were statistically analyzed through the computerized recording.

RESULTS

The mean angle between the axis of corneal astigmatism and the axis of total astigmatism was 5.73 degrees +/- 3.97 degrees in myopic patients, 3.13 degrees +/- 2.49 degrees in mixture astigmatism patients and 6.35 degrees +/- 4.20 degrees in hyperopic patients.

CONCLUSION

The angle between the axis of corneal astigmatism and the axis of total astigmatism in the refractive state was mainly caused by the difference of the axises of surface astigmatism of lens and cornea.

Mooren's ulcer in China: a study of clinical characteristics and treatment

AIMS

To investigate the clinical characteristics and compare the effects of several methods of treatment of Mooren's corneal ulcer.

METHODS

550 consecutive cases of Mooren's corneal ulcer were analysed in patients, including age, sex, laterality of eye, ulcer location, perforative rate, cure rate of surgeries, recurrent rate, the effects of conjunctiva excision, lamellar keratoplasty (LKP), and LKP plus 1% cyclosporin A eye drops.

RESULTS

The average age of onset was 48.4 years of age. The ratio of males to females was 1:0. 74. 165 (30%) cases had the disease bilaterally, of which 52 (31.5%) occurred in the young age group and 113 (68.5%) in the old age group. Ulcers of 501 eyes (70.1%) were located at the limbus of the palpebral fissure. The perforation rate was 13.3%, with perforation of 41 eyes (43.2%) occurring in the young age group and 54 (56.8%) in the old age group. Postoperative recurrence rate was 25.6%. The cure rate of the first procedure of LKP plus 1% cyclosporin A eye drops was 73.7%. The final cure rate was 95.6%, and the postoperative preservation rate of the eye globe was 99.7%.

CONCLUSION

This primary study provided the clinical characteristics of patients with Mooren's corneal ulcer in China. LKP plus 1% cyclosporin A eye drops was an effective treatment.

[Dendritic cell infiltration in lung adenocarcinoma and its effect on prognosis]

OBJECTIVE

To study the infiltration degree of dendritic cells in lung adenocarcinoma and its effect on prognosis.

METHODS

S-100 protein was used as the specific marker for dendritic cells, and immunohistochemistry was employed to detect the distribution of dendritic cells in lung adenocarcinoma.

RESULTS

Among 46 cases of lung adenocarcinoma, 19 were markedly infiltrated by dendritic cells, the five-year survival rate being 61%; 27 showed slight infiltration, the five-year survival rate being 21%. Among the 46 cases of adenocarcinoma, 26 were low differentiated adenocarcinoma, in which 10 were infiltrated markedly by dendritic cells, five-year survival rate being 57%; and 16 were slightly infiltrated, five-year survival rate being 16%. These data were evaluated with the log-rank test, which showed a significant difference between the markedly infiltrated group and the slightly infiltrated group.

CONCLUSION

The prognosis of lung adenocarcinoma which markedly infiltrated by dendritic cells is better than that of slightly infiltrated by dendritic cells.

Combinatorial screening of enzyme activity by using multiplexed capillary electrophoresis

Efficient and comprehensive screening of enzyme activity was accomplished in a combinatorial array of 96 reaction microvials. Quantitation of the extent of the reaction at well-defined time intervals was achieved by using 96-capillary array electrophoresis coupled with a multiplexed absorption detector. Capillary electrophoresis provides high separation resolution to isolate the product from the reactants. Absorption detection provides universal applicability to combinatorial screening. For the conversion of NADH to NAD+, the catalytic activity of LDH was confirmed to be the highest at pH 7. This scheme should be useful for high-throughput drug discovery, clinical diagnosis, substrate binding, as well as combinatorial synthesis.

High-throughput comprehensive peptide mapping of proteins by multiplexed capillary electrophoresis

A novel multimodal method for peptide mapping of proteins by multiplexed capillary electrophoresis (CE) is presented. By combining charge to size separations in four different channels and micellar electrokinetic chromatography for hydrophobicity-based separations in two different channels in a 96-capillary array, peptide fragments of digested proteins were readily resolved and showed unique fingerprints. Each capillary spanned several diodes in a photodiode array (PDA) for absorption measurement. The 96 capillaries were monitored simultaneously at 214 nm by a single PDA element with 1,024 diodes, and analysis was completed within 45 min. This demonstrates that it is possible to rapidly screen biotechnological products as well as to efficiently optimize separation conditions in CE by a combinatorial approach.

Specificity determinants for the pyruvate dehydrogenase component reaction mapped with mutated and prosthetic group modified lipoyl domains

Efficient catalysis in the second step of the pyruvate dehydrogenase (E1) component reaction requires a lipoyl group to be attached to a lipoyl domain that displays appropriately positioned specificity residues. As substrates, the human dihydrolipoyl acetyltransferase provides an N-terminal (L1) and an inner (L2) lipoyl domain. We evaluated the specificity requirements for the E1 reaction with 27 mutant L2 (including four substitutions for the lipoylated lysine, Lys(173)), with three analogs substituted for the lipoyl group on Lys(173), and with selected L1 mutants. Besides Lys(173) mutants, only E170Q mutation prevented lipoylation. Based on analysis of the structural stability of mutants by differential scanning calorimetry, alanine substitutions of residues with aromatic side chains in terminal regions outside the folded portion of the L2 domain significantly decreased the stability of mutant L2, suggesting specific interactions of these terminal regions with the folded domain. E1 reaction rates were markedly reduced by the following substitutions in the L2 domain (equivalent site-L1): L140A, S141A (S14A-L1), T143A, E162A, D172N, and E179A (E52A-L1). These mutants gave diverse changes in kinetic parameters. These residues are spread over >24 A on one side of the L2 structure, supporting extensive contact between E1 and L2 domain. Alignment of over 40 lipoyl domain sequences supports Ser(141), Thr(143), and Glu(179) serving as specificity residues for use by E1 from eukaryotic sources. Extensive interactions of the lipoyl-lysine prosthetic group within the active site are supported by the limited inhibition of E1 acetylation of native L2 by L2 domains altered either by mutation of Lys(173) or enzymatic addition of lipoate analogs to Lys(173). Thus, efficient use by mammalian E1 of cognate lipoyl domains derives from unique surface residues with critical interactions contributed by the universal lipoyl-lysine prosthetic group, key specificity residues, and some conserved residues, particularly Asp(172) adjacent to Lys(173).

Genetic typing and HIV-1 diagnosis by using 96 capillary array electrophoresis and ultraviolet absorption detection

Current high-throughput approaches to the analysis of PCR products are based primarily on electrophoretic separation and laser-excited fluorescence detection. We show that capillary array electrophoresis can be applied to HIV-1 diagnosis and D1S80 VNTR genetic typing based simply on UV absorption detection. The additive contribution of each base pair to the total absorption signal provides adequate detection sensitivity for analyzing most PCR products. Not only is the use of specialized and potentially toxic fluorescent labels eliminated, but also the complexity and cost of the instrumentation are greatly reduced.

Erhaia (Gastropoda: Rissooidea): phylogenetic relationships and the question of Paragonimus coevolution in Asia

The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoidea and Rissooidea. The question whether or not Paragonimus shows the same specificity of host-parasite coevolved relationship as the human blood fluke Schistosoma was inspired by the finding of two sympatric snail species as hosts for Paragonimus skrjabini in Fujian Province, China: Gammatricula and Erhaia. The former species can clearly be classified as Pomatiopsidae: Triculinae. The latter has previously been classified as Pomatiopsidae: Pomatiopsinae. However, this classification based on anatomical characteristics is uncertain. In order to obtain a robust phylogenetic hypothesis for Erhaia, we have studied three gene fragments from this taxon as well as from twelve related taxa. The data show that the species involved represent four families: Pomatiopsidae, Hydrobiidae, Cochliopidae (here raised to family status), and Amnicolidae. Erhaia fits securely into the Amnicolidae. This indicates that P. skrjabini has not coevolved with snail lineages. However, P. skrjabini has so far only been reported from rissooidean snails, whereas members of the Paragonimus westermani complex have only been found in ceritheoidean snails. The implication is that there is a host specificity on the superfamily level. However, Asian freshwater species of the Ceritheoidea and Rissooidea usually are not sympatric and often prefer different habitats. It is therefore possible that ecological niche partitioning plays the primary role for Paragonimus evolution.

Microsurgical treatment of Mooren's ulcer

OBJECTIVE

To evaluate effect of microsurgery of lamellar keratoplasty (LKP) on Mooren's corneal ulcer.

METHODS

The effect, postoperative astigmatism, postoperative vision, ulcer recurrence of postoperation, and surgical complications of two groups of consecutive Mooren's ulcer inpatients treated respectively by non-microsurgery of LKP and microsurgery of LKP were analyzed.

RESULTS

There were significant differences of the effect, postoperative astigmatism, postoperative vision, ulcer recurrence of postoperation, and surgical complications between the two groups. The effect and postoperative vision of the microsurgery-treated group were better than those of the non-microsurgery-treated group. The postoperative astigmatism, ulcer recurrence of postoperation, and surgical complications of the microsurgery-treated group were less than those of the nonmicrosurgery-treated group.

CONCLUSION

Microsurgery of LKP of Mooren's corneal ulcer can greatly improve the ulcer healing and postoperative vision, and reduce the surgical complication and the ulcer recurrence of postoperation.

[Tumor infiltrating dendritic cells in relation to prognosis of lung cancer]

OBJECTIVE

To study the degree of infiltration of dendritic cells in lung cancer in relation to prognosis.

METHODS

S-100 protein as the marker of tumor-infiltraing dendritic cells (TIDC) was stained immunohistochemically in lung cancer specimens. The degree of infiltration was considered mild and marked according to the criteria reported by Furukawa. The survival rate was obtained by Log-rank test of the data.

RESULTS

In 15 of 38 adenocarcinomas, whose TIDC infiltration was marked, the five-year survival rate was 60.0%, while in 23 with mild TIDC infiltration, the five-year survival rate was 21.7% (P < 0.01) Quite similar data were obtained from 44 squamous-cell carcinomas. Significantly higher five-year survival rate (61.1%) was observed in those with marked TIDC than those with mild infiltration (19.2%).

CONCLUSION

The degree of TIDC infiltration is positively correlated with the survival rate of lung carcinoma patients.

Characterization and gene structure of a novel retinoblastoma-protein-associated protein similar to the transcription regulator TFII-I

Retinoblastoma protein (Rb) is an important regulator of vertebrate cell cycle and development. It functions through a direct interaction with protein factors involved in cell cycle progression and differentiation. In the present study we characterized a novel Rb-associated protein, Cream1, which bound to Rb specifically through a C-terminal region. Cream1 contained 959 amino acid residues and migrated as a protein of approx. 120 kDa on SDS/PAGE. It was a widely expressed nuclear protein with a nuclear localization signal resembling that of the large T antigen of simian virus 40. Its primary sequence was characteristic of five direct repeats that were similar to, but distinct from, those of TFII-I, a multifunctional transcription regulator. Three additional regions were also highly conserved in both proteins. Cream1 exhibited an activation activity that was attributed to its N-terminal portion when assayed in yeast. Its relationship with the muscle-enhancer-binding protein MusTRD1 further suggests a role in regulating gene expression. The structural gene, CREAM1, contained 27 exons and spanned more than 150 kb. It was located at human chromosome 7q11.23 in a region deleted for Williams' syndrome, a neurodevelopmental disease with multisystem abnormalities, implying its involvement in certain disorders. Taken together, our results suggest that Cream1 might serve as a positive transcription regulator under the control of Rb.

Lop12, a mutation in mouse Crygd causing lens opacity similar to human Coppock cataract

A new cataract mutation was discovered in an ongoing program to identify new mouse models of hereditary eye disease. Lens opacity 12 (Lop12) is a semidominant mutation that results in an irregular nuclear lens opacity similar to the human Coppock cataract. Lop12 is associated with a small nonrecombining segment that maps to mouse Chromosome 1 close to the eye lens obsolescence mutation (Cryge(Cat2-Elo)), a member of the gamma-crystallin gene cluster (Cryg). Using a systemic candidate gene approach to analyze the entire Cryg cluster, a G to A transition was found in exon 3 of Crygd associated with the Lop12 mutation and has been designated Crygd(Lop12). The mutation Crygd(Lop12) leads to the formation of an in-frame stop codon that produces a truncated protein of 156 amino acids. It is predicted that the defective gene product alters protein folding of the gamma-crystallin(s) and results in lens opacity.

A molecular perspective on the genera Paragonimus Braun, Euparagonimus Chen and Pagumogonimus Chen

The status of the genera Euparagonimus Chen, 1963 and Pagumogonimus Chen, 1963 relative to Paragonimus Braun, 1899 was investigated using DNA sequences from the mitochondrial cytochrome c oxidase subunit I (CO1) gene (partial) and the nuclear ribosomal DNA second internal transcribed spacer (ITS2). In the phylogenetic trees constructed, the genus Pagumogonimus is clearly not monophyletic and therefore not a natural taxon. Indeed, the type species of Pagumogonimus, P. skrjabini from China, is very closely related to Paragonimus miyazakii from Japan. The status of Euparagonimus is less obvious. Euparagonimus cenocopiosus lies distant from other lungflukes included in the analysis. It can be placed as sister to Paragonimus in some analyses and falls within the genus in others. A recently published morphological study placed E. cenocopiosus within the genus Paragonimus and probably this is where it should remain.

The effects of tetrandrine on the contractile function and microvascular permeability in the stunned myocardium of rats

The effects of tetrandrine (Tet) on the contractile function and microvascular permeability in stunned rat myocardium in vivo were studied. Stunned myocardium was induced by 15 (MS(15) group) or 20 (MS(20) group) min of myocardial ischemia plus 60 min of reperfusion. The following was shown. (1) FITC-BSA concentration was 166.0 +/- 7. 9 microg/g myocardium in the control group. The concentrations in ischemic myocardium increased by 35.4 and 45.6% in MS(15) and MS(20) groups respectively (p<0.05). (2) Administration of Tet (64.2 and 96. 3 micromol/kg, I.P.) 20 min before ischemia not only ameliorated the contractile function, but also reduced the FITC-BSA concentrations in ischemic myocardium. At 60 min after reperfusion, the contractile function parameters in Tet-treated groups were significantly superior to those in corresponding stunning groups. FITC-BSA concentrations in Tet-treated groups were lower than those in stunning groups. Then, there was already no significant difference in FITC-BSA concentrations between Tet-treated groups and the control group. The FITC-BSA concentrations at the end of experiments were correlated negatively with dp/dt(max) (r = -0.83, p<0.01). (3) Tet inhibited KCl-induced calcium influx in isolated cardiomyocytes. The results suggest that Tet given before ischemia may be involved in the reduction of microvascular permeability in stunned myocardium, which might be associated with its calcium channel blocking effect.

[Experimental study of ta chengchi tang decoction for relieving lung injury during acute necrotizing pancreatitis]

The objectives of the study were to investigate the changes of leukocyte adhesiveness and tumor necrosis factor (TNF) in the early stage of acute necrotizing pancreatitis (ANP), to go further into the relation of those changes to lung injury of ANP, and to evaluate the prohibitive effect of ta chengchi tang Decoction on leukocyte adhesion and TNF secretion. 14 canines were randomly divided into 3 groups. The treatment group (n = 5): experimental ANP model treated with ta chengchi tang Decoction; the saline control group (n = 5): experimental ANP model treated with normal saline; and the sham operative group (n = 4). The adhesion of leukocytes to vascular endothelial cells and TNF activities in serum and in bronchi-alveolar lavage fluid (BALF) were observed and measured, and the degrees of lung injury were assessed. The results showed that the adhesiveness of leukocytes was markedly increased and the activities of TNF were elevated in peripheral blood and BALF during ANP; that the leukocyte adhesiveness in the treatment group was weaker than that in the saline group (P < 0.05) and the serum and BALF TNF activities were also significantly lower than those in the saline group (P < 0.01); and that the degrees of lung injury in the treatment group were significantly milder than those in the saline group. These indicate that the increased leukocyte adhesiveness and hypersecretion of TNF take part in the pathogenesis of lung injury in ANP, and ta chengchi tang Decoction is demonstrated an efficacious medicine for alleviating the degree of lung injury mediated by both the leukocyte adhesion and TNF in ANP.

Ribozyme-mediated down-regulation of ErbB-4 in estrogen receptor-positive breast cancer cells inhibits proliferation both in vitro and in vivo

ErbB-4 is a recently discovered member of the class I receptor tyrosine kinase family (ErbB). Little is known about its expression and its importance in human malignancy. To delineate the biological function of ErbB-4 receptors in breast cancer, we used a hammerhead ribozyme strategy to achieve down-regulation of ErbB-4 receptors in various breast cancer cell lines. We observed that down-regulation of ErbB-4 in estrogen receptor-positive (ER+) human breast cancer cell lines (MCF-7 and T47D), which express relatively high levels of ErbB-4, significantly inhibited colony formation. No effects were observed in estrogen receptor-negative (ER-) MDA-MB-453 cells, which express low levels of endogenous ErbB4 and high levels of ErbB-2 and ErbB-3. This occurred despite the fact that fluorescence-activated cell sorter analysis of these latter cells revealed that the expression of the ErbB-4 receptor was completely abrogated by ribozyme treatment. Furthermore, down-regulation of ErbB-4 in T47D and MCF-7 cells significantly inhibited tumor formation in athymic nude mice (P < 0.03 and P < 0.001, respectively). In addition, NRG-stimulated phosphorylation of ErbB-4- and NRG-induced colony formation was significantly reduced in ribozyme-transfected T47D cells. These data provide the first evidence that elevation of ErbB-4 expression plays a role in the proliferation of some ER+ human breast cancer cell lines (T47D and MCF-7) that express high levels of ErbB-4. We have also investigated the expression of ErbB-4 in human primary breast carcinoma specimens, using immunohistochemical staining with an anti-ErbB-4 monoclonal antibody. ErbB-4 expression was found in 60% of the 50 primary breast tumors examined, and high intense immunoreactivity of ErbB-4 was detected in 18% of these primary breast tumors. ErbB-4 receptor expression appeared to correlate with ER+ primary breast tumors. A similar correlation was also observed in the human breast cancer cell lines. These results provide a better understanding of the biological significance of ErbB-4 receptor in breast cancer. Our data suggest that elevation of the ErbB-4 receptor plays a role in ER+ breast cancer cell proliferation. Moreover, ribozyme technology provides a useful tool to delineate the role of a particular gene product.

[K-ras mutation in pancreatic juice from patients with pancreatic carcinoma]

OBJECTIVE

Pancreatic neoplasm, which is considered as one of the most malignant tumors in humans, is now increasing steadily in frequency. The 5-year-survival rate is less than 5%. In order to detect it in early stage, we tried to analyze K-ras mutation in pancreatic juice collected during ERCP after injection of secretin. Mutation of coden 12 in exon 1 of K-ras gene was reported as high as 90% in pancreatic cancer, but much less in benign pancreatic disease.

METHODS

47 patients at Peking Union Medical College Hospital between 1994 and 1998 were enrolled. Pancreatic juice collected during ERCP after injection of 100u secretin, was briefly centrifuged and the sediment was resuspended with PBS. Pancreatic juice supernatant and pancreatic cells were stored at -80 degrees C separately. DNA of the cells and supernatant of the juice were extracted. K-ras point mutation was investigated in the DNA of these supernatant and cells by means of two-stage polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP).

RESULTS

When the supernatant of the pancreatic juice was used, the PCR successful rate was 82%, K-ras mutation rate of the pancreatic carcinomas was 71% (15/21) compared with 0% (0/7) in benign pancreatic disease (3 chronic pancreatitis, 3 insulinoma and 1 pancreatic cyst). When the centrifuged pancreatic cells were used, the successful rate increased to 96%, sixty-five percent (11/17) of pancreatic carcinomas had K-ras mutation; mutation was also detected in 1/7 of the cases with benign pancreatic diseases (an insulinoma). In total, 78% (21/27) of the cases with pancreatic carcinomas has mutant alleles compared with 8% (1/13) of the benign pancreatic diseases (P < 0.001) when pancreatic juice was used to detect K-ras gene point mutation. In terms of the location of the pancreatic cancer, K-ras mutation rate was not statistically different between the head (80%) and the body + tail (75%). The mutation rate did not vary with the size of the tumor.

CONCLUSION

Detection of coden 12 of K-ras mutation in pancreatic juice can be used in differentiating pancreatic carcinomas from benign pancreatic diseases. It has high sensitivity and specificity.

[Glossus flap for hypopharyngeal reparation]

OBJECTIVE

To research the surgical type for hypopharyngeal reparation.

METHOD

The glossus flap with glossus deep arterial was made to repairing hypopharyngeal breach after total laryngotomy and partial hypopharyngotomy in 12 cases of repeated laryngeal carcinoma and hypopharyngeal carcinoma.

RESULT

11 cases recovered in the swallowing function after 15 days and the pharyngeal fistula took place in one case, but healed in 35 days postoperatively. The survival rates in 1 year, 3 years and 5 years were 81.8%, 66.7% and 50% respectively.

CONCLUSION

The glossus flap is good material for hypopharyngeal reparation with rich blood supply, few complication and high survival rates.

In vivo hemodynamic evaluation based on transverse Doppler measurements of blood velocities and vessel diameter

We have developed a method for simultaneously measuring the blood flow velocity distributions along a line perpendicular to the vessel wall and the instantaneous diameter of the common carotid artery. Thus, the wall shear rates and shear rate distribution across the arterial lumen could be computed accurately. In this method, transverse Doppler technique is combined with ultrasonic A echo-mode, using only one single crystal transducer. In order to satisfy the requirements of high spatial and velocity resolutions, especially extending to a very low velocity range in the case of low signal-to-noise ratio, a combination scheme of 10-MHz operating frequency, sample volume tracking, 12-bit A/D, 512-point fast Fourier transform with 5-kHz sample rate, spectrum average, variable threshold for bandwidth estimation, smoothing of velocity curves, and hardware was carefully designed. The velocity distribution measurements based on transverse Doppler spectrums were also validated under the steady flow conditions using a flow loop system. Results from this study show this ultrasonic system to be capable of measuring the shear rates at wall accurately and shear rate distributions across the common carotid arterial lumen.

Stroke therapy in traditional Chinese medicine (TCM): prospects for drug discovery and development

Brain injuries resulting from stroke are a major and increasing public health problem in both developed and developing countries worldwide. China's extensive experience in the use of traditional Chinese medicines (TCMs) in stroke therapy indicates that TCM preparations are effective, with few or no side-effects. There are more than 100 traditional medicines in use for stroke therapy in China. Some of their therapeutic effects in stroke have been confirmed by recent clinical studies. A large number of compounds have been isolated from TCMs and most of these resources have not yet been characterized for pharmacological purposes. Here, this article explains how TCM provides an extensive and knowledge-rich foundation for implementing a strategically focused pharmacological research programme aimed at the development of new drugs.

Neurite outgrowth in PC12 cells. Distinguishing the roles of ubiquitylation and ubiquitin-dependent proteolysis

Nerve growth factor (NGF)-induced neurite outgrowth from rat PC12 cells was coincident with elevated (>/=2-fold) levels of endogenous ubiquitin (Ub) protein conjugates, elevated rates of formation of 125I-labeled Ub approximately E1 (Ub-activating enzyme) thiol esters and 125I-labeled Ub approximately E2 (Ub carrier protein) thiol esters in vitro, and enhanced capacity to synthesize 125I-labeled Ub-protein conjugates de novo. Activities of at least four E2s were increased in NGF-treated cells, including E2(14K), a component of the N-end rule pathway. Ubiquitylation of 125 I-labeled beta-lactoglobulin was up to 4-fold greater in supernatants from NGF-treated cells versus untreated cells and was selectively inhibited by the dipeptide Leu-Ala, an inhibitor of Ub isopeptide ligase (E3). However, Ub-dependent proteolysis of 125I-labeled beta-lactoglobulin was not increased in supernatants from NGF-treated cells, suggesting that neurite outgrowth is promoted by enhanced rates of synthesis (rather than degradation) of Ub-protein conjugates. Consistent with this observation, neurite outgrowth was induced by proteasome inhibitors (lactacystin and clasto-lactacystin beta-lactone) and was associated with elevated levels of ubiquitylated protein and stabilization of the Ub-dependent substrate, p53. Lactacystin-induced neurite outgrowth was blocked by the dipeptide Leu-Ala (2 mM) but not by His-Ala. These data 1) demonstrate that the enhanced pool of ubiquitylated protein observed during neuritogenesis in PC12 cells reflects coordinated up-regulation of Ub-conjugating activity, 2) suggest that Ub-dependent proteolysis is a negative regulator of neurite outgrowth in vitro, and 3) support a role for E2(14K)/E3-mediated protein ubiquitylation in PC12 cell neurite outgrowth.

[The influence of different treatment of the etched enamel on bracket bonding effect]

OBJECTIVE:To inquire into the influence of three different treatment of the etched enamel on bracket bonding effect. METHODS:Compared the bracket bonding failure rate and ARI counts of 30 cases which treat the etched enamel surface with 5s air-water gun rinsing, wet cotton ball wiping and alcohol cotton ball wiping respectively. RESULTS: The bracket bonding failure rate of the group which rinse the etched enamel 5s with air-water gun in the lowest one.There are statistically significant difference between this group and two others.The ARI count of this group is higher than that of others. CONCLUSION:The results suggest that rinse the etched enamel with the air-water gun is a very important step to prevent the bracket bonding failure.

Immunological studies on the cellular phenotype involved in corneal allograft rejection

OBJECTIVE

To investigate the cellular phenotype involved in corneal allograft rejection using wholemounts analysis.

METHODS

Corneal transplantation was performed between Sprague Dawley (SD) and Wistar rats. Corneal wholemounts were prepared from control rats and those after corneal transplantation on day 7 and 12. Immunohistochemical stain was performed on these wholemounts using monoclonal antibodies to transforming growth factor beta 1(TGF-beta 1), CD3, CD4, CD8, B lymphocytes, macrophages, dendritic cells and major histocompatibility complex (MHC) class II antigen.

RESULTS

Corneal allograft rejection started on day 7 and reached its maximum from 10 to 14 days after corneal transplantation. Presence of TGF-beta 1-, CD3-, CD4-, CD8-, MHC class II-positive cells, macrophages and dendritic cells were noted at the limbus of both SD rats and Wistar rats. No positive cell was present in the central cornea of normal rats. All positive cells but B lymphocyte were noted in large numbers in the cornea after corneal allograft transplantation. Marked staining for TGF-beta 1 was noted during graft rejection.

CONCLUSION

The corneal wholemounts technique provides a good visualization for the cellular phenotype involved in corneal allograft rejection. A variety of cells including TGF-beta 1, CD3, CD4, CD8, MHC class II antigen positive cells, macrophages and dendritic cells are involved in corneal allograft rejection. TGF-beta 1-positive cell might be an important immunosuppressive factor after corneal transplantation and also involved in the induction of fibrosis.

[A clinical analysis of Mooren's corneal ulcer]

OBJECTIVE

To investigate the clinical characteristics and to compare the effects of several therapies of Mooren's corneal ulcer.

METHODS

550 consecutive in-patients with Mooren's corneal ulcer were clinically analyzed, including the age, sex, laterality of the eye, ulcer location, rate of perforation, cure rate of surgeries, recurrent rate, and the effects of conjunctiva excision, lamellar keratoplasty (LKP), LKP plus cyclosporin A eye drops.

RESULTS

The average age of onset of the ulcer was 48.4 years old, the ratio of male to female was 1:0.74, bilateral disease occurred in 165 cases (30.0%) of whom 52 cases (31.5%) were in the younger group and 113 (68.5%) in the older group. There were 501 eyes (70.1%) with the ulcer located at the limbus of palpebral fissure, and 95 out of 715 eyes with the disease had corneal perforation, the rate of perforation being 13.3%, 41 cases (43.2%) in the younger group and 54 cases (56.8%) in the older group. The postoperative recurrent rate was 25.6%. The cure rate of once LKP plus cyclosporin A eye drops was 73.7%, the final cure rate was 95.6%, and the preservative rate of the corneal anatomical structure of the surgeries was 99.7%.

CONCLUSION

LKP plus cyclosporin A eye drops is an effective treatment of Mooren's corneal ulcer.

Ubiquitin-dependent pathway is up-regulated in differentiating lens cells

The mammalian eye lens is composed of two distinct types of cells, epithelial cells and fiber cells. The fiber cells are generated throughout life via continuous differentiation of epithelial cells. Differentiation of lens cells involves dramatic changes in cellular components including altered activity of the ubiquitin dependent pathway. The concentration of high mass ubiquitin conjugates in the mitotically active-, differentiating-equatorial epithelial cells was 5-10 fold higher than that observed in mitotically quiescent, non-differentiated, central epithelial cells, even though there was a significant dilution of non-crystallin proteins due to an increase in level of crystallins in the differentiating cells. Similar observations were made when differentiation was modeled by exposure of lens epithelial explants to bFGF in culture. Activities of ubiquitin-activating enzyme (E1) and ubiquitin-conjugating enzymes (E2s) in the differentiating equatorial epithelial cells were also up to 100% higher than those noted in non-differentiated central epithelial cells and E1 appears to be rate controlling for ubiquitinylation. Consistent with the higher concentrations of high mass ubiquitin conjugates, there was a trend of enhanced ability to execute ATP-dependent protein degradation in the differentiating equatorial epithelial cells as compared with degradation in the non-differentiated central epithelial cells. These data indicate that the ubiquitin dependent pathway is up-regulated during differentiation of lens cells. In the differentiated fibers, the concentration of high mass ubiquitin conjugates and relative activities of E1 and E2s were 50% lower than in the non-differentiated central epithelial cells. In comparison, the concentration of the 110 kDa E1 was unchanged in differentiated fibers. However, if the factor of dilution by the significant increase in the level of crystallins was taken into account, the level or activities of the components of ubiquitin pathway in the differentiated cells was higher than the level noted in non-differentiated cells. These data indicate that, as compared with other non-crystallin proteins, there is differential stabilization and/or synthesis of the 110 kDa E1 and some other components of the ubiquitin dependent pathway in differentiated fibers.

Genetic factors influence cataract formation in alpha 3 connexin knockout mice

Connexin alpha 3 (Cx46 or Gja3) gene targeted null mice developed lens nuclear cataracts shortly after birth. A large variance in the cataracts was observed in alpha 3 null sibs on a mixed 129SvJae X C57BL/6J F3 background. This suggested that the genetic background might influence the cataract phenotype. Therefore, we placed the alpha 3 null mutation into a 129SvJae background, and also backcrossed the mutation for six generations into 129SvJ and C57BL/6J backgrounds. While alpha 3 nulls on the two 129 backgrounds contained severe cataracts associated with gamma crystallin cleavage, alpha 3 nulls on the C57B16 background had far milder cataracts with no detectable gamma crystallin cleavage. These findings suggest that a genetic modifier exists that influences gamma crystallin stability, and that gamma crystallin breakdown is associated with severe nuclear cataracts.

Gap junctional coupling in lenses lacking alpha3 connexin

Fiber cells of the lens are interconnected by an extensive network of gap junctions containing alpha3 (Cx46) and alpha8 (Cx50) connexins. A specific role for these connexins in lens homeostasis is not known. To determine the contribution of these connexins to lens function, we used impedance techniques to study cell-to-cell coupling in lenses from homozygous alpha3 knockout (-/-), heterozygous (+/-), and wild-type (+/+) mice. Western blots and immunofluorescence data indicated that alpha8 remained at similar levels in the three classes of lenses, whereas alpha3 was approximately 50% of the normal level in the +/- lenses, and it was absent from the -/- lenses. Moreover, the data from +/+ lenses suggest that a cleavage of connexins occurs abruptly between the peripheral shell of differentiating fibers (DF) and the inner core of mature fibers (MF). The appearance of the cleaved connexins was correlated to a change in the coupling conductance. In -/- lenses the coupling conductance of MF was zero, and these fibers were depolarized by about 30 mV from normal (approximately -65 mV). The DF remained coupled, but the conductance was reduced to 30-35% of normal. However, the gap junctions in the DF of alpha3 -/- lenses remained sensitive to pH. We conclude that alpha3 connexin is necessary for the coupling of central fibers to peripheral cells, and that this coupling is essential for fiber cell homeostasis because uncoupled MF depolarize and subsequently become opaque.

Calorie restriction, stress and the ubiquitin-dependent pathway in mouse livers

Calorie restriction (R) is the only known method to delay the aging process and extend mean and maximal lifespan in rodents. R has been shown to delay the age-related accumulation of damaged proteins and to protect organisms from various stresses which can produce damaged proteins. Such stresses include irradiation, heat shock, and oxidative stress. The ubiquitin- and ATP-dependent proteolytic pathway (UPP) has been associated with the degradation of abnormal and/or damaged proteins. We examined the effect of diet and oxidative stress on activities of the UPP in supernatants from livers taken from 23-month-old Emory mice which had been exposed to an in-vivo injection of paraquat. Paraquat induces oxidative stress by generating superoxide radicals. In livers from non-stressed animals, steady-state levels of endogenous ubiquitin conjugates, de novo conjugate formation, and E1 and E2 activities were significantly lower in R animals than in control (C) animals. However, after exposure to paraquat, levels of endogenous ubiquitin conjugates were significantly higher in R versus C animals, and de novo conjugate formation and E1 and E2 activities in R animals rose to levels which were indistinguishable from levels of these activities noted in C animals. R was associated with an increased ability to degrade beta-lactoglobulin by the UPP after an oxidative stress was imposed. Ability to degrade beta-lactoglobulin by the C or R livers in non-stressed animals was not significantly different. Taken together, these data indicate that oxidative stress in R animals is associated with enhanced levels of ubiquitin conjugates and that this enhancement may be due to an increase in UPP activity. These data also indicate that the ability to form ubiquitin conjugates and the UPP system does not change with oxidative stress in C animals. The latter is consistent with prior reports that suggests that older C animals may already be in a state of enhanced oxidative stress and that activities of the UPP provide a sensitive indicator of levels of cellular redox status.

[An analysis of curative effect of activator in treating Class II division 1 malocclusion]

OBJECTIVE

To analyze the results of class II division 1 malocclusion treated by activator.

METHODS

Sixteen growing patients, who were diagnosed as class II division 1 malocclusion, were evaluated by McNamara analysis.

RESULTS

The activator affects the growth of mandible positively and inhibits the growth of the maxilla.

CONCLUSION

The activator can treat class II division 1 malocclusion effectively, which can be perceived by McNamara analysis directly.

[An ideal imaging quality can be obtained from the evenly scattering x-ray density]

Since X-ray image quality was evaluated by the self-delivering function, the limitations in the application of fixative focus X-ray tube seem more outstanding. How to improve the quality of the x-ray image has been one of the focus problems in the field of the x-ray diagnosis. If we use the x-ray tube of the evenly scattering x-ray density as the radio source, we can get the ideal images.

HIV-1 envelope gp120 inhibits the monocyte response to chemokines through CD4 signal-dependent chemokine receptor down-regulation

Since HIV-1 infection results in severe immunosuppression, and the envelope protein gp120 has been reported to interact with some of the chemokine receptors on human T lymphocytes, we postulated that gp120 may also affect monocyte activation by a variety of chemokines. This study shows that human peripheral blood monocytes when preincubated with gp120 either purified from laboratory-adapted strains or as recombinant proteins exhibited markedly reduced binding, calcium mobilization, and chemotactic response to chemokines. The gp-120-pretreated monocytes also showed a decreased response to FMLP. This broad inhibition of monocyte activation by chemoattractants required interaction of gp120 with CD4, since the effect of gp120 was only observed in CD4+ monocytes and in HEK 293 cells only if cotransfected with both chemokine receptors and an intact CD4, but not a CD4 lacking its cytoplasmic domain. Anti-CD4 mAbs mimicked the effect of gp120, and both anti-CD4 Ab and gp120 caused internalization of CXCR4 in HEK 293 cells provided they also expressed CD4. Staurosporine blocked the inhibitory effect of gp120 on monocytes, suggesting that cellular signaling was required for gp120 to inhibit the response of CD4+ cells to chemoattractants. Our study demonstrates a broad suppressive effect of gp120 on monocyte activation by chemoattractants through the down-regulation of cell surface receptors. Thus, gp120 may be used by HIV-1 to disarm the monocyte response to inflammatory stimulation.