Mechanisms of metabolic dyslipidemia in insulin resistant states: deregulation of hepatic and intestinal lipoprotein secretion

The growing epidemic of the metabolic syndrome is now well recognized and there is widespread effort to understand the pathogenesis of this complex syndrome and its major metabolic consequences. One of the severe complications accompanying insulin resistant states is the hypertriglyceridemia that appears to occur largely due to overproduction of triglyceride-rich, apolipoprotein B (apoB) containing-lipoproteins. As a result, mechanisms regulating the overproduction of these atherogenic apoB-containing lipoproteins have been the focus of much investigation in recent years. Both in vitro as well as in vivo models of insulin resistance are currently being used to further our understanding of the mechanisms involved in the deregulation of lipid metabolism in insulin resistant states. Evidence from these animal models as well as human studies has identified hepatic very low density lipoprotein (VLDL) overproduction as a critical underlying factor in the development of hypertriglyceridemia and metabolic dyslipidemia. In recent years, a dietary animal model of insulin resistance, the fructose-fed hamster model developed in our laboratory, has proven invaluable in studies of the link between development of an insulin resistant state, derangement of hepatic lipoprotein metabolism, and overproduction of apoB-containing lipoproteins. Evidence from the fructose-fed hamster model now indicates oversecretion of both hepatically-derived apoB100-containing VLDL as well as intestinal apoB48-containing triglyceride-rich lipoproteins in insulin resistant states. A number of novel intracellular factors that may be involved in modulation of VLDL have also been identified. This review focuses on these recent developments and examines the hypothesis that a complex interaction among enhanced flux of free fatty acids from peripheral tissues to liver and intestine, chronic up-regulation of de novo lipogenesis by hyperinsulinemia, and attenuated insulin signaling in the liver and the intestine may be critical to lipoprotein overproduction accompanying insulin resistance.

A concerted, rational design of type 1 17beta-hydroxysteroid dehydrogenase inhibitors: estradiol-adenosine hybrids with high affinity

Human estrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD type 1) catalyzes the final step in the synthesis of active estrogens that stimulate the proliferation of breast cancer cells. Based on the initial premise to make use of the binding energies of both the substrate and cofactor sites, and molecular modeling starting from the enzyme structure, several estradiol-adenosine hybrids were designed and synthesized. Among these hybrids, EM-1745 with a linker of 8-CH2 groups is proved to be the best competitive inhibitor with a Ki of 3.0 +/- 0.8 nM. The crystal structure of the EM-1745 enzyme complex at 1.6 A provides evidence at atomic resolution of strong interactions between both the steroid and cofactor moieties and the enzyme molecule, as illustrated by a deltaA-weighted 2Fo-Fc electron density map contoured at 3.0 delta. The substrate entry loop is further stabilized in this complex compared with previous complexes of the enzyme. These results confirm our initial strategy of combining studies of structural biology and enzyme mechanism in the inhibitor design, which may be applied to other steroidogenic enzymes involved in human diseases.

Quantitative study of macroscopic quantum tunneling in a dc SQUID: a system with two degrees of freedom

To test whether the theory of macroscopic quantum tunneling (MQT) is applicable to systems with 2 degrees of freedom, we experimentally investigated the switching current distribution of a dc SQUID. Using sample parameters determined from measurements at T=4.2 K, we are able to make quantitative comparison to the theories from 8 mK to 4.2 K. The excellent agreement between the data and the MQT theory demonstrates that tunneling from the zero-voltage state of the dc SQUID is well described by the quantum mechanics.

GSH-dependent photolabeling of multidrug resistance protein MRP1 (ABCC1) by [125I]LY475776. Evidence of a major binding site in the COOH-proximal membrane spanning domain

Substrates transported by the 190-kDa multidrug resistance protein 1 (MRP1) (ABCC1) include endogenous organic anions such as the cysteinyl leukotriene C(4). In addition, MRP1 confers resistance against various anticancer drugs by reducing intracellular accumulation by co-export of drug with reduced GSH. We have examined the properties of LY475776, an intrinsically photoactivable MRP1-specific tricyclic isoxazole modulator that inhibits leukotriene C(4) transport by this protein in a GSH-dependent manner. We show that [125I]LY475776 photolabeling of MRP1 requires GSH but is also supported by several non-reducing GSH derivatives and peptide analogs. Limited proteolysis revealed that [(125)I]LY475776 labeling was confined to the 75-kDa COOH-proximal half of MRP1. More extensive proteolysis generated two major 125I-labeled fragments of approximately 56 and approximately 41 kDa, and immunoblotting with regionally directed antibodies showed that these fragments correspond to amino acids approximately 1045-1531 and approximately 1150-1531, respectively. However, an approximately 33-kDa COOH-terminal immunoreactive fragment was not labeled, inferring that the major [125I]LY475776-labeling site resides approximately between amino acids 1150-1250. This region encompasses transmembrane (TM) segments 16 and 17 at the COOH-proximal end of the third membrane spanning domain of the protein. [125I]LY475776 labeling of mutant MRP1 molecules with substitutions of Trp(1246) in TM17 were reduced >80% compared with wild-type MRP1, confirming that TM17 is important for LY475776 binding. Finally, vanadate-induced trapping of ADP inhibited [125I]LY475776 labeling, suggesting that ATP hydrolysis causes a conformational change in MRP1 that reduces the affinity of the protein for this inhibitor.

Human ribonucleotide reductase M2 subunit gene amplification and transcriptional regulation in a homogeneous staining chromosome region responsible for the mechanism of drug resistance

In our previous publication it was shown that a Gemcitabine-resistant KBGem clone derived from step-wise exposure to Gemcitabine resulted in overexpression of the human Ribonucleotide Reductase M2 subunit (hRRM2) mRNA and protein (Goan et al., 1999). In this study we confirm these results and show that the hRRM2 gene amplification arises in a homogeneous staining region (hsr) derived from chromosome translocation. The hydroxyurea-resistant clone (KBHURs) was studied as a comparison. PCR analysis of the hRRM2 gene promoter confirmed the amplification. Northern and Western blots were further employed to confirm the gene amplification and hRRM2 mRNA and protein expression were compatible with the level of drug resistance. Cells synchronized by serum starvation and then returned to serum-containing growth conditions showed a rapid induction of high levels of transcription of the hRRM2 gene. To clarify whether expression of hRRM2 mRNA was regulated at a transcriptional level, several transcription factors, including AP-1, Sp1, AP-2, CREB, NF-kappa B, and OCT1, were examined by gel-shift assay. Interestingly, the KBGem clone was regulated by different transcription factors than the KBHURs clone. Compared to the wild-type KB cells (KBwt), the KBGem clone exhibited a different binding pattern for Sp1 and NF-kappa B. The KBHURs clone, however, demonstrated a unique binding pattern with AP-1 and CREB, different from the KBwt control as well as the KBGem clone. Therefore, we conclude that the drug-resistant phenotype is associated with human RRM2 gene amplification from a homogeneous staining chromosome region and altered transcription regulation. Each clone demonstrated a unique pattern of transcription factor binding that may play a vital role in the mechanism of drug resistance.

Purification, crystallization and preliminary X-ray diffraction results of human 17beta-hydroxysteroid dehydrogenase type 5

17beta-Hydroxysteroid dehydrogenases (17beta-HSDs) catalyze the last step in the biosynthesis of all androgens and estrogens, thus playing a pivotal role in sex-hormone metabolism. Human 17beta-HSD type 5 (17beta-HSD5) catalyzes hydride transfer at the 17beta-hydroxy position, but possesses high sequence homology to 3alpha-hydroxysteroid dehydrogenases (3alpha-HSD). Two crystal forms of 17beta-HSD5 in an enzyme-testosterone-NADP ternary complex have been obtained under different crystallization conditions. A form I crystal obtained at pH 8.5 diffracted to 1.32 A. It belonged to space group P2(1), with unit-cell parameters a = 47.41, b = 77.16, c = 48.67 A, beta = 116.32 degrees. Form II crystals obtained at pH 6.5 diffracted to 2.0 A and belonged to space group P6(3), with unit-cell parameters a = b = 110.58, c = 56.89 A.

Adaptive filtering of evoked potentials with radial-basis-function neural network prefilter

Evoked potentials (EPs) are time-varying signals typically buried in relatively large background noise. To extract the EP more effectively from noise, we had previously developed an approach using an adaptive signal enhancer (ASE) (Chen et al., 1995). ASE requires a proper reference input signal for its optimal performance. Ensemble- and moving window-averages were formerly used with good results. In this paper, we present a new method to provide even more effective reference inputs for the ASE. Specifically, a Gaussian radial basis function neural network (RBFNN) was used to preprocess raw EP signals before serving as the reference input. Since the RBFNN has built-in nonlinear activation functions that enable it to closely fit any function mapping, the output of RBFNN can effectively track the signal variations of EP. Results confirmed the superior performance of ASE with RBFNN over the previous method.

Relations among early postexposure noise-induced threshold shifts and permanent threshold shifts in the chinchilla

Threshold shifts (TS) were measured at various times following a wide variety of noise exposures on over 900 chinchillas. An analysis of postexposure TS measures and noise-induced permanent threshold shift (PTS) showed that, across audiometric test frequency, there was a consistent relation between these variables of the form PTS (dB) = alpha(e(TS/beta) - 1), where, for a given test frequency, alpha (dB) and beta (dB) are constants. TSs were measured immediately following exposure (TS0), 24 h after exposure (TS24), and at several intermediate times in order to estimate the maximum TS (TSmax). Correlation between TS and PTS at the various test frequencies was highest for TS24. An analysis of the 90th-percentile PTS showed a linear growth of PTS with TS24 of approximately 0.7 dB PTS/dB TS24. These data provide some support, in the chinchilla model, for a variation of the three postulates originally presented by Kryter et al. [J. Acoust. Soc. Am. 39, 451 (1966)]. Specifically: (i) TS24 is a consistent measure of the effects of a traumatic noise exposure. (ii) All exposures that produce a given TS24 will be equally hazardous. (iii) Noise-induced PTS in the most susceptible animals, following many years of exposure, is approximately equal to (0.7)TS24 measured after an 8-h exposure to the same noise.

Energy-independent factors influencing noise-induced hearing loss in the chinchilla model

The effects on hearing and the sensory cell population of four continuous, non-Gaussian noise exposures each having an A-weighted L(eq)=100 dB SPL were compared to the effects of an energy-equivalent Gaussian noise. The non-Gaussian noise conditions were characterized by the statistical metric, kurtosis (beta), computed on the unfiltered, beta(t), and the filtered, beta(f), time-domain signals. The chinchilla (n=58) was used as the animal model. Hearing thresholds were estimated using auditory-evoked potentials (AEP) recorded from the inferior colliculus and sensory cell populations were obtained from surface preparation histology. Despite equivalent exposure energies, the four non-Gaussian conditions produced considerably greater hearing and sensory cell loss than did the Gaussian condition. The magnitude of this excess trauma produced by the non-Gaussian noise was dependent on the frequency content, but not on the average energy content of the impacts which gave the noise its non-Gaussian character. These results indicate that beta(t) is an appropriate index of the increased hazard of exposure to non-Gaussian noises and that beta(f) may be useful in the prediction of the place-specific additional outer hair cell loss produced by non-Gaussian exposures. The results also suggest that energy-based metrics, while necessary for the prediction of noise-induced hearing loss, are not sufficient.

Solid-phase microextraction of monocyclic aromatic amines using novel fibers coated with crown ether

Three solid-phase microextraction (SPME) fibers prepared by the sol-gel method, containing hydroxydibenzo-14-crown-4 (OH-DB14C4), dihydroxy-substituted saturated urushiol crown ether (DHSU14C4) and 3,5-dibutyl-unsymmetry-dibenzo-14-crown-4-dihydroxy crown ether (DBUD14C4), respectively, were evaluated for the determination of aromatic amine (aniline, m-toluidine, N,N-diethylaniline, N-ethyl-m-toluidine, 3,4-dimethylaniline). The sol-gel-derived hydroxy-dibenzo14-crown-4-coated fiber has the best affinity for several aniline derivatives. Optimization was carried out for the determination of aromatic amines with SPME fibers. The linearity was from 0.11 to 29 microg/ml and detection limits varied from 0.17 to 0.98 ng/ml. Relative standard deviation (n=5) was found to be 3.23-6.20%. The coating proved to be very stable at high temperature (to 340 degrees C) and in different solvents (organic and inorganic). The method was applied to the determination of aromatic amines in wastewater samples from a pharmaceutical factory.

The shorter zinc finger protein ZNF230 gene message is transcribed in fertile male testes and may be related to human spermatogenesis

The zinc finger gene family represents one of the largest in the mammalian genome, with several of these genes reported to be involved in spermatogenesis. A newly discovered gene has been identified that is expressed abundantly in the testicular tissue of fertile men as determined by mRNA differential display. The gene encodes a C(3)HC(4)-type zinc finger protein motif (ring finger motif) consistent with a role in pre-meiotic or post-meiotic sperm development. The gene was named ZNF230 and mapped to the short arm of chromosome 11 (11p15). ZNF230 has two transcripts, of 1 kb and 4.4 kb in length. The shorter 1 kb transcript was only detected in testicular tissue whereas the longer 4.4 kb transcript was not detected in testis but was found in several other tissues. The lack of detectable ZNF230 expression in azoospermic patients by reverse transcriptase-mediated PCR analysis is interpreted to mean that this gene is involved in maintaining normal human male fertility.

Go!Poly: A gene-oriented polymorphism database

Human genome polymorphisms play a key role in defining the molecular basis of phenotypic differences between individuals in aspects such as disease susceptibility and drug responses. The database requirements for supporting the study of human genetic variation have been well recognized. In order to meet these needs, several generalized databases have been built. However, it is still hard for users to find gene-related variation data from these huge and sophisticated databases. In its role as a gene-oriented directory of polymorphism data, Go!Poly (Gene Oriented Polymorphism Database; http://61.139.84.5/gopoly/) utilizes two new highly curated and non-redundant resources, LocusLink (http://www.ncbi.nlm.nih.gov/LocusLink/) and RefSeq (http://www.ncbi.nlm.nih.gov/LocusLink/refseq.html), as the standard for identifying and positioning nucleotide variations. As a generalized polymorphism database, Go!Poly extracts human gene-linked sequence variations of all common types (SNP, insertion-deletion, simple tandem repeat, and complex nucleotides variations) from various public resources including scientific journals and internet resources, such as HGBASE (http://hgbase.cgr.ki.se) and dbSNP (http://www.ncbi.nlm.nih.gov/SNP/). The polymorphism data are then categorized into different gene loci, and the reference sequences given by LocusLink are used as positioning references. Through close integration with LocusLink, Go!Poly also provides facilitated connections among sequence data, gene name, and related biological information. This feature also makes Go!Poly easy to search and navigate. Future automated annotations and internal consistency checking may also benefit from this. Extensive efforts are being taken to make the polymorphism information generated by the Chinese scientific community available from this resource.

Return to fertility after extended chemical castration with a GnRH antagonist

BACKGROUND

Antagonistic analogues of GnRH for the treatment of prostate cancer may be used clinically in persons for whom return to fertility after such treatment is important or desirable. The purpose of this study was, therefore, to evaluate the effects of a long term treatment with orntide, a GnRH antagonist, on testosterone levels and fertility in male rats.

METHODS

Two groups of male rats received either 120-day orntide microspheres (8.8 mg orntide/kg/120 days) or vehicle alone (control group). Serum orntide and testosterone levels in both groups were monitored at certain intervals for 9 months from the initiation of treatment. After recovery of normal serum testosterone levels in the treated animals, each rat was housed with two proven breeder, but drug-naive, females.

RESULTS

All mates of treated rats achieved pregnancy as rapidly as the mates of control rats although two of the control rats did not sire a litter with either female and one sired only one litter. The mean size of the litters of treated (12.3 offspring per litter) and control (10.6 offspring per litter) were similar. All offspring were grossly normal morphologically and behaviorally during the time to weaning.

CONCLUSIONS

These results suggest that lack of fertility due to testosterone suppression is reversible after cessation of treatment with this GnRH antagonist.

Characterization of binding of leukotriene C4 by human multidrug resistance protein 1: evidence of differential interactions with NH2- and COOH-proximal halves of the protein

Multidrug resistance protein 1 (MRP1) is capable of actively transporting a wide range of conjugated and unconjugated organic anions. The protein can also transport additional conjugated and unconjugated compounds in a GSH- or S-methyl GSH-stimulated manner. How MRP1 binds and transports such structurally diverse substrates is not known. We have used [(3)H]leukotriene C(4) (LTC(4)), a high affinity glutathione-conjugated physiological substrate, to photolabel intact MRP1, as well as fragments of the protein expressed in insect cells. These studies revealed that: (i) LTC(4) labels sites in the NH(2)- and COOH-proximal halves of MRP1, (ii) labeling of the NH(2)-half of MRP1 is localized to a region encompassing membrane-spanning domain (MSD) 2 and nucleotide binding domain (NBD) 1, (iii) labeling of this region is dependent on the presence of all or part of the cytoplasmic loop (CL3) linking MSD1 and MSD2, but not on the presence of MSD1, (iv) labeling of the NH(2)-proximal site is preferentially inhibited by S-methyl GSH, (v) labeling of the COOH-proximal half of the protein occurs in a region encompassing transmembrane helices 14-17 and appears not to require NBD2 or the cytoplasmic COOH-terminal region of the protein, (vi) labeling of intact MRP1 by LTC(4) is strongly attenuated in the presence of ATP and vanadate, and this decrease in labeling is attributable to a marked reduction in LTC(4) binding to the NH(2)-proximal site, and (vii) the attenuation of LTC(4) binding to the NH(2)-proximal site is a consequence of ATP hydrolysis and trapping of Vi-ADP exclusively at NBD2. These data suggest that MRP1-mediated transport involves a conformational change, driven by ATP hydrolysis at NBD2, that alters the affinity with which LTC(4) binds to one of two sites composed, at least in part, of elements in the NH(2)-proximal half of the protein.

Determinants of shear stress-stimulated endothelial nitric oxide production assessed in real-time by 4,5-diaminofluorescein fluorescence

The extremely short biological half-life of endothelial-derived nitric oxide (NO) has impeded real-time measurements of NO synthesis. We used the membrane-permeable fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2 DA) to study determinants of NO synthesis in bovine aortic endothelial cells (BAECs). A step increase in shear stress (SS) from 0.3 to 3.4 dyne/cm(2) triggered an increase in DAF-2 fluorescence starting 3.0 +/- 0.5 min after the flow rise and peaking at 44.7 +/- 7.2 min. This was abolished by intracellular Ca(2+) chelation, but was unaffected by blocking extracellular Ca(2+) influx or by inhibiting SS-related changes in intracellular pH. The increase in DAF-2 fluorescence occurred significantly earlier in BAECs transfected with either superoxide dismutase (SOD) or catalase (CAT), indicating concomitant reactive oxygen species (ROS) generation by SS and "competition" between ROS- and DAF-2-NO interactions. These data provide novel insights into several NO signaling determinants and reveal that DAF-2 can assess real-time SS-stimulated NO synthesis in endothelial cells. This should facilitate the analysis of NO-signaling pathways.

Growth and development in term infants fed long-chain polyunsaturated fatty acids: a double-masked, randomized, parallel, prospective, multivariate study

OBJECTIVE

To evaluate the effects of dietary intake of the long-chain polyunsaturated fatty acids, arachidonic acid (AA), and docosahexaenoic acid (DHA) on multiple indices of infant growth and development.

DESIGN

A double-masked, randomized, parallel trial was conducted with term infants fed formulas with or without AA+DHA for 1 year (N = 239). Reference groups of breastfed infants (N = 165) weaned to formulas with and without AA+DHA were also studied. Infants in the formula groups were randomized at </=9 days of age to a control formula with no AA or DHA (n = 77) or 1 of 2 otherwise identical formulas containing AA+DHA (AA, 0.46% and DHA, 0.14% of total fatty acids) from either egg-derived triglyceride (egg-DTG [n=80]) or fish oil and fungal oil (fish/fungal [n = 82]) at levels similar to the average in breast milk samples as measured in the reference group. All formulas contained 50% of energy from fat with the essential dietary fatty acids, linoleic acid (20% fatty acids) and alpha-linolenic acid (2% fatty acids). The main study outcomes were AA and DHA levels in plasma and red blood cells, and multiple measures of infant development at multiple ages from birth to 14 months: growth, visual acuity, information processing, general development, language, and temperament.

RESULTS

AA and DHA levels in plasma and red cells were higher in AA+DHA-supplemented groups than in the control formula group and comparable to those in reference groups. No developmental test results distinguished these groups. Expected differences in family demographics associated with breastfeeding were found, but no advantages to breastfeeding on any of the developmental outcome demonstrated.

CONCLUSIONS

These findings do not support adding AA+DHA to formulas containing 10% energy as linoleic acid and 1% energy as alpha-linolenic acid to enhance growth, visual acuity, information processing, general development, language, or temperament in healthy, term infants during the first 14 months after birth.infant development, breast feeding, infant formula, long-chain polyunsaturated fatty acids, docosahexaenoic acid.

Defective interfering RNAs of a satellite virus

Panicum mosaic virus (PMV) is a recently molecularly characterized RNA virus with the unique feature of supporting the replication of two subviral RNAs in a few species of the family Gramineae. The subviral agents include a satellite RNA (satRNA) that is devoid of a coding region and the unrelated satellite panicum mosaic virus (SPMV) that encodes its own capsid protein. Here we report the association of this complex with a new entity in the RNA world, a defective-interfering RNA (DI) of a satellite virus. The specificity of interactions governing this four-component viral system is illustrated by the ability of the SPMV DIs to strongly interfere with the accumulation of the parental SPMV. The SPMV DIs do not interfere with PMV satRNA, but they do slightly enhance the rate of spread and titer of PMV. The SPMV-derived DIs provide an additional avenue by which to investigate fundamental biological questions, including the evolution and interactions of infectious RNAs.

Solid-phase microextraction using fused-silica fibers coated with sol-gel-derived hydroxy-crown ether

A novel solid-phase microextraction (SPME) fiber containing hydroxydibenzo-14-crown-4 (OH-DB14C4)/hydroxy-terminated silicone oil (OH-TSO) was first prepared by a sol-gel method and investigated for the determination of phenols. The possible mechanism is discussed and confirmed by IR spectra. The coating has stable performance in high temperature (to 350 degrees C) and solvents (organic and inorganic) due to the chemical binding between the coating and the fiber surface. The addition of crown ether enhances the polarity of the coating compared with that of the sol-gel OH-terminated silicone oil fiber and, accordingly, provides higher extraction efficiency for polar phenolic compounds. On the other hand, OH-terminated silicone oil in the coating can not only increase the length of network but also help to spread the stationary phase on the silica surface uniformly. The fluorescence microscopy experiment suggests the benefit the more uniform surface of the sol-gel-derived OHDB14C4/OH-TSO fiber in comparison with sol-gelderived OH-DB14C4 fiber. Some parameters of the SPME fiber for the determination of phenols were investigated. Limits of detection of the phenols are below 1.0 ng/mL, and the precisions are from 2.9 to 4.6% (n = 6). Linear ranges were found to be 0.1-10 microg/mL The sensitivity of the method is enhanced at a low-pH level (pH approximately 1) and with the addition of salt. The method was applied to the analysis of wastewater sample from a paper mill.

Mutation of a single conserved tryptophan in multidrug resistance protein 1 (MRP1/ABCC1) results in loss of drug resistance and selective loss of organic anion transport

Multidrug resistance protein 1 (MRP1/ABCC1) belongs to the ATP-binding cassette transporter superfamily and is capable of conferring resistance to a broad range of chemotherapeutic agents and transporting structurally diverse conjugated organic anions. In this study, we found that substitution of a highly conserved tryptophan at position 1246 with cysteine (W1246C-MRP1) in the putative last transmembrane segment (TM17) of MRP1 eliminated 17beta-estradiol 17-(beta-d-glucuronide) (E(2)17betaG) transport by membrane vesicles prepared from transiently transfected human embryonic kidney cells while leaving the capacity for leukotriene C(4)- and verapamil-stimulated glutathione transport intact. In addition, in contrast to wild-type MRP1, leukotriene C(4) transport by the W1246C-MRP1 protein was no longer inhibitable by E(2)17betaG, indicating that the mutant protein had lost the ability to bind the glucuronide. A similar phenotype was observed when Trp(1246) was replaced with Ala, Phe, and Tyr. Confocal microscopy of cells expressing Trp(1246) mutant MRP1 molecules fused at the C terminus with green fluorescent protein showed that they were correctly routed to the plasma membrane. In addition to the loss of E(2)17betaG transport, HeLa cells stably transfected with W1246C-MRP1 cDNA were not resistant to the Vinca alkaloid vincristine and accumulated levels of [(3)H]vincristine comparable to those in vector control-transfected cells. Cells expressing W1246C-MRP1 were also not resistant to cationic anthracyclines (doxorubicin, daunorubicin) or the electroneutral epipodophyllotoxin VP-16. In contrast, resistance to sodium arsenite was only partially diminished, and resistance to potassium antimony tartrate remained comparable to that of cells expressing wild-type MRP1. This suggests that the structural determinants required for transport of heavy metal oxyanions differ from those for chemotherapeutic agents. Our results provide the first example of a tryptophan residue being so critically important for substrate specificity in a eukaryotic ATP-binding cassette transporter.

Isolation, characterization, and mapping of a novel human KRAB zinc finger protein encoding gene ZNF463

A novel human KRAB (Krüppel associated box) type zinc finger protein encoding gene, ZNF463, was obtained by mRNA differential display and RACE. It consists of 1904 nucleotides and encodes a protein of 463 amino acids with an amino-terminal KRAB domain and 12 carboxy-terminal C2H2 zinc finger units. The gene is mapped to chromosome 19q13.3 approximately 4 by FISH. As from Northern blot analysis ZNF463 is only expressed in testis, RT-PCR indicates that ZNF463 is expressed more highly in normal fertile adults than in fetus and azoospermic patients suggesting that it may play a role in human spermatogenesis.

Metabolites and analogs of 1alpha,25-dihydroxyvitamin D(3): evaluation of actions in bone

Analogs of 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] activate both genomic mechanisms via the nuclear vitamin D(3) receptor (nVDR) and nongenomic pathways via the plasma membrane vitamin D(3) receptor (pmVDR). Both of these pathways are normally activated by 1alpha,25(OH)(2)D(3), but as a result of synthesis of numerous analogs of 1alpha,25(OH)(2)D(3) these pathways can be distinguished. We used increasing doses of vitamin D(3) analogs to determine their potencies of action on these two distinct pathways, measuring calcium channel potentiation as an indicator of the nongenomic action and measuring increases in osteocalcin mRNA and protein release and bone resorption as indicators of genomic action. We found that both 25(OH)-16,23E-diene-D(3) (R) and 1alpha,25(OH)(2)-16,23E-diene-D(3) (A) are 10-fold more potent than 1alpha,25(OH)(2)D(3) for activation of the nongenomic pathway because double bonds in the side chain and the D ring increase the affinity for calcium channel potentiation. While the C-1alpha-hydroxyl group is not necessary for potentiation of calcium channels, methyl groups at this position can alter the affinity for calcium channel potentiation. On the other hand, 1000 fold higher concentrations of nongenomic analogs were needed compared to 1alpha,25(OH)(2)D(3) to increase osteocalcin mRNA or protein release. 1alpha,25-Dihydroxy-16-ene-23-yne-26,27-hexafluorovitamin D(3), (E) is an agent that is 10 fold more potent than 1alpha,25(OH)(2)D(3) at increasing osteocalcin mRNA and protein release, whereas 1alpha,25(OH)(2)-3-epi-D(3) increases osteocalcin mRNA and protein with a potency over 10 fold lower than 1alpha,25(OH)(2)D(3). These results suggest that double bonds in the side chain and the D ring stabilize action on the nongenomic pathway whereas F(6) on the terminal portion of the side chain increases potency for nVDR. On the other hand, while the C-1alpha-hydroxyl group is necessary for activation of genomic events via nVDR, the activation of nongenomic events occurs in the absence of this group.

Retention of a small replicase gene segment in tomato bushy stunt virus defective RNAs inhibits their helper-mediated trans-accumulation

Tomato bushy stunt virus (TBSV) and other tombusviruses are notorious for their propensity to accumulate defective interfering RNAs (DIs) upon serial passage through experimental Nicotiana species. Hallmarks of this occurrence include reduced levels of helper RNA and protein accumulation and amelioration of the lethal necrosis induced upon infection of the host with the helper viruses alone. The objective of this study was to determine whether the prolific trans-accumulation of defective RNAs typically occurs for all replicase-deficient TBSV mutants, or if this process is influenced by internal cis-acting elements that have been excised from DIs. For this purpose, various replicase-deficient TBSV cDNA constructs were generated and their transcripts were tested for trans-accumulation competence in the presence of helper virus. The results revealed that a region of ca. 150 nucleotides near the center of the replicase gene, with a predicted high degree of secondary structure, was a potent inhibitor of trans-rescue (ITR) by TBSV. Relocation of the ITR into efficiently trans-replicating DIs inhibited their accumulation drastically, but only when inserted in the reverse orientation and with an intact 5' ITR-specific predicted hairpin structure. Insertion of the ITR element in the positive orientation yielded DI transcripts that were able to replicate, but failed to interfere noticeably with either accumulation of the helper RNA or the onset of the lethal necrosis phenotype in N. benthamiana. In conclusion, the ITR has an intrinsic capacity to inhibit trans-accumulation of defective RNAs, but its stringency and biological effects are strongly influenced by the overall sequence context.

[An epidemiological survey of blindness and low vision in Meixian County]

OBJECTIVE

To study the status of blindness and low vision in Meixian County.

METHODS

The stratified random sampling rule and the standard grading system of blindness set by WHO were adopted in the study, and 11 327 subjects were enrolled (a sampling fraction of 2.01%) in the whole county.

RESULTS

The prevalence of bilateral blindness and low vision was found to be 0.47% and 0.89%; that of monocular blindness and low vision was 0.72% and 0.59%, respectively. Subjects over 50 years old had a significantly higher prevalence of blindness and low vision. The causes leading to blindness and low vision were, in falling order, cataract, glaucoma, ametropia/amblyopia and pterygium.

CONCLUSION

The treatment of cataract is the main measure to decrease the prevalence of blindness and low vision.

Genetic identification of multiple biological roles associated with the capsid protein of satellite panicum mosaic virus

Satellite panicum mosaic virus (SPMV), an 824-nucleotide, positive-sense, single-stranded RNA virus, depends on Panicum mosaic virus (PMV) for replication and spread in host plants. Compared with PMV infection alone, symptoms are intensified and develop faster on millet plants infected with SPMV and PMV. SPMV encodes a 157 amino acid capsid protein (CP) (17.5 kDa) to encapsidate SPMV RNA and form T = 1 satellite virions. The present study identifies additional biological activities of the SPMV CP, including the induction of severe chlorosis on proso millet plants (Panicum miliaceum cv. Sunup or Red Turghai). Initial deletion mutagenesis experiments mapped the chlorosis-inducing domain to amino acids 50 to 157 on the C-terminal portion of the SPMV CP. More defined analyses revealed that amino acids 124 to 135 comprised a critical domain associated with chlorosis induction and virion formation, whereas the extreme C-terminal residues 148 to 157 were not strictly essential for either role. The results also demonstrated that the absence of SPMV CP tended to stimulate the accumulation of defective RNAs. This suggests that the SPMV CP plays a significant role in maintaining the structural integrity of the full-length satellite virus RNA and harbors multiple functions associated with pathogenesis in SPMV-infected host plants.

Detection and differentiation of CAV-1 and CAV-2 by polymerase chain reaction

Canine adenovirus type 1 (CAV-1) and type 2 (CAV-2) can be categorized in the laboratory by haemagglutination and neutralization tests, but they are difficult to differentiate from each other in specimens, especially when infection occurs in the digestive tract. The object of this study was to develop a simple method of detecting and differentiating them. One pair of common primers was designed and synthesized according to the sequences of the E3 and flanking regions and a polymerase chain reaction (PCR) assay was established using these two primers to amplify the virus-specific DNA fragment from clinical specimens as well as from cell cultures. After elecctrophoresis, under the same amplification conditions, 508 bp and 1030 bp PCR products were observed for CAV-1 and CAV-2, respectively. These were further shown to be adenovirus specific by dot hybridization and sequencing. As only one pair of primers was involved in the PCR procedure, it was faster and easier to perform than any of the other assays used for detecting canine adenovirus, making it applicable in the rapid confirmation of diagnosis and differentiation of the two types of canine adenoviruses.

Correlations among evoked potential thresholds, distortion product otoacoustic emissions and hair cell loss following various noise exposures in the chinchilla

Changes in cubic distortion product otoacoustic emissions (DeltaDPOAEs), evoked potential threshold shifts (TSs) and outer hair cell (OHC) losses were measured in a population of 95 noise-exposed chinchillas. Each animal was exposed to one of 23 different noises in an asymptotic threshold shift (ATS) producing paradigm or an interrupted noise paradigm which typically produced a toughening effect. Noises were narrow band (400 Hz) impacts with center frequencies of 0.5, 1.0, 2.0, 4.0 or 8.0 kHz presented 1 impact/s at peak SPLs of 109, 115, 121 or 127 dB. The duration of the exposures was 24 h/day for 5 days (ATS paradigm) or 6 h/day for 20 days (toughening paradigm). Based on a linear regression analysis of individual subject and group mean data, correlations among the following dependent variables were made: DeltaDPOAEs, ATS, toughening or TS recovery (TS(r)), permanent threshold shift (PTS) and OHC loss. Correlations among these metrics were generally highest for DPOAE primary frequency levels, L(1)=L(2)=70 dB. Correlation between DeltaDPOAE and TS(r) was typically low, while a considerably higher correlation was found between DeltaDPOAE and ATS. Correlations among the permanent measures of noise-induced effects, i.e. for DeltaDPOAE/PTS and DeltaDPOAE/OHC loss were typically poor when there was only a small or a moderate noise-induced effect (PTS<25 dB and DeltaDPOAE<20 dB). However, for PTS<25 dB the correlation between PTS and OHC loss was considerably better than the correlation between DeltaDPOAE and OHC loss. For more severe noise-induced changes there was generally a good correspondence between OHC loss, PTS and DeltaDPOAE metrics.

[Computer-aided compose panoramic arthroscopic images of the temporomandibular joint]

OBJECTIVE

The computer-aided image processing method is established to compose arthroscopic images of temporomandibular joints(TMJs).

METHODS

Arthroscopic images were input directly into a personal computer and recorded at a compact disk. By using the software- Photoshop 5.0 for Window 95, the images were edited and adjusted to form sagittal and/or coronal panoramic images of articular surfaces.

RESULTS

The normal sagittal and coronal two-dimensional integrated panoramic arthroscopic images of TMJ were obtained, and qualities of these images were satisfied.

CONCLUSION

The arthroscopic panoramic images established by using this method can demonstrate integrated structures of articular surfaces directly.

[Diagnostic values of MRI in combination with DSA in vascular malformations of the head and neck]

OBJECTIVE

To evaluate prospectively diagnostic values of magnetic resonance imaging (MRI) as the initial examination for vascular malformations of the head and neck, and establish a flowchart based on radiodiagnostic features.

METHODS

45 patients with vascular malformations of the head and neck were evaluated prospectively with MRI. MRI was followed by angiography in 15 patients, contrast-enhanced CT in 15 patients. MRI was performed by using spin-echo pulse sequences with Philips Gyroscan NT 1.0 Teslaunit.

RESULTS

In all cases, MRI demonstrated usefully, and there was no other single imaging modality that could provide information about internal structures and flow characteristics as much as MRI. It made differentiation between high-flow and low-flow lesions obvious, however MRI was inferior to angiography in delineation of feeder vessels.

CONCLUSION

MRI can be used as the initial methods for diagnosis of vascular malformations in the head and neck, and could be combined with angiography in cases with high-flow or combined-flow lesions.

Hormones increase mRNA of cyclic-nucleotide-gated cation channels in airway epithelia

Previous studies have shown that the mRNA of cyclic-nucleotide-gated nonselective cation (CNG) channels is expressed in rat airway epithelia and that these channels contribute to sodium-mediated short-circuit currents in cultured rat tracheal epithelia. Patch-clamp studies from human A549 cells indicate that these channels contribute to cGMP-stimulated L-cis-diltiazem- and dichlorobenzamil-inhibited whole-cell sodium currents. This study demonstrates that mRNA for primary and secondary subunits of CNG channels, halphaCNG1 and hbetaCNG1 respectively, are expressed in several human airway cell lines, including normal and cystic fibrosis bronchial airway cells, in normal and cystic fibrosis tracheal airway cell lines and nasal polyp tissue from a cystic fibrosis patient. The mRNA of ralphaCNG1 in rat lung increased in response to increased circulating glucocorticoids and decreased in animals with lowered circulating glucocorticoids after aminoglutethimide treatment. Likewise the mRNA of halphaCNG1 increased in the presence of glucocorticoids in cultured alveolar airway cells. The mRNA of alphaCNG1 in rat lung was also increased in response to a low-salt diet and lowered in animals fed a high-salt diet. Likewise the mRNA of alphaCNG1 was increased in response to increased aldosterone and decreased in animals given spironolactone. These results suggest that mRNA for alphaCNG1 increases in response to elevated glucocorticoids or mineralocorticoids. Because alphaCNG1 is a functional sodium entry channel in both rat and human airway epithelial cells, if channel protein is also elevated this channel could mediate an increase in sodium absorption across lung epithelia in response to circulating hormones.

Use of green fluorescent protein-conjugated beta-actin as a novel molecular marker for in vitro tumor cell chemotaxis assay

To study the dynamics of actin cytoskeleton rearrangement in living cells, an eukaryotic expression vector expressing a beta-actin-GFP fusion protein was generated. The expression construct when transfected into NIH3T3 fibroblast, A2058 human melanoma and 293T human embryonic kidney carcinoma cell lines expressed beta-actin-GFP fusion protein, which colocalized with endogenous cellular actin as determined by histoimmunofluorescence staining. The beta-actin-GFP was also observed to be reorganized in response to treatments with the chemoattractant type IV collagen. Cells extended pseudopodial protrusions and altered the morphology of their cortical structure in response to type IV collagen stimulation. More importantly, beta-actin-GFP accumulated in areas undergoing these dynamic cytoskeleton changes, indicating that beta-actin-GFP could participate in actin polymerization. Although ectopic expression of beta-actin-GFP lead to minor side effects on cell proliferation, these studies suggest that this strategy provides an alternative to the invasive techniques currently used to study actin dynamics and permits real-time visualization of actin rearrangements in response to environmental cues.

Cell type-specific regulation of B-Raf kinase by cAMP and 14-3-3 proteins

Cyclic AMP can either activate or inhibit the mitogen-activated protein kinase (MAPK) pathway in different cell types; MAPK activation has been observed in B-Raf-expressing cells and has been attributed to Rap1 activation with subsequent B-Raf activation, whereas MAPK inhibition has been observed in cells lacking B-Raf and has been attributed to cAMP-dependent protein kinase (protein kinase A)-mediated phosphorylation and inhibition of Raf-1 kinase. We found that cAMP stimulated MAPK activity in CHO-K1 and PC12 cells but inhibited MAPK activity in C6 and NB2A cells. In all four cell types, cAMP activated Rap1, and the 95- and 68-kDa isoforms of B-Raf were expressed. cAMP activation or inhibition of MAPK correlated with activation or inhibition of endogenous and transfected B-Raf kinase. Although all cell types expressed similar amounts of 14-3-3 proteins, approximately 5-fold less 14-3-3 was associated with B-Raf in cells in which cAMP was inhibitory than in cells in which cAMP was stimulatory. We found that the cell type-specific inhibition of B-Raf could be completely prevented by overexpression of 14-3-3 isoforms, whereas expression of a dominant negative 14-3-3 mutant resulted in partial loss of B-Raf activity. Our data suggest that 14-3-3 bound to B-Raf protects the enzyme from protein kinase A-mediated inhibition; the amount of 14-3-3 associated with B-Raf may explain the tissue-specific effects of cAMP on B-Raf kinase activity.

[Clinical application of computed arthroscope of the temporomandibular joint]

OBJECTIVE

The effect of clinical application on the computed arthroscope of the temporomandibular joint (TMJ) is evaluated.

METHODS

The single arthroscopic images were input into computer and memorized into magneto optical disk. With the help of Photoshop 5.0 in WINDOWS 95, the images were combined by technique of virtual process, adjusted by rotation of images, marginal blur, and chromatism correction to compound sagittal and/or coronal panoramic images of articular surfaces. According to different needs, the composite images can be printed with different printers. During the period from May 1998 to May 1999, the TMJ preoperative panoramic images were composed with computed arthroscope (CA) in the 32 joints. Of them, there were 12 joints with internal derangement (ID), 8 osteoarthrosis (OA), 8 adhesion, 2 disk perforation, and 2 synovial chondromatosis. The post-operative panoramic images were also made up to evaluate the surgical effects in 10 joints.

RESULTS

In all of 32 joints, the 32 panoramic arthroscopic images of upper cavities were composed. In addition, the images of lower cavities were composed in 2 OA and 1 perforation. The postoperative panoramic images were also made up in 4 OA, 4 adhesion, and 2 synovial chondromatosis. All of the above-mentioned images showed integrally the entire structure of articular cavity, intracapsular pathologic/surgical appearances, and the relationships among the different tissues or articular surfaces.

CONCLUSION

The CA can enhance the comprehensive ability of diagnostic arthroscope, and help to exchange and spread the experiences of the TMJ arthroscopic surgery.

Outgrowth of chondrocytes from human articular cartilage explants and expression of alpha-smooth muscle actin

The objectives of this study were to investigate the effect of various enzymatic treatments on the outgrowth of chondrocytes from explants of adult human articular cartilage and the expression of a specific contractile protein isoform, alpha-smooth muscle actin, known to facilitate wound closure in other connective tissues. Explants of articular cartilage were prepared from specimens obtained from patients undergoing total joint arthroplasty. The time to cell outgrowth in vitro was determined and the expression of alpha-smooth muscle actin shown by immunohistochemistry. Treatment of the explants with collagenase for 15 minutes reduced the time to outgrowth from more than 30 days to 3 days. Hyaluronidase, chondroitinase ABC, and trypsin applied for the 15-minute period had no effect on the time to cell outgrowth when compared with untreated controls. Pretreatment with hyaluronidase prior to collagenase reduced the time to outgrowth. A notable finding of this study was that the majority of chondrocytes in the adult human articular cartilage specimens and virtually all of the outgrowing cells contained alpha-smooth muscle actin. We conclude that human articular chondrocytes have the capability to migrate through enzymatically degraded matrix and express a contractile actin isoform. Collagenase treatment reduces the time required for cell outgrowth.

[Effects of maxillary growth of Wistar rats with bilateral artificial cleft palate after premaxillary orthopedic treatment on expression of proliferating cell nuclear antigen(PCNA)]

OBJECTIVE

Being based on the principle of Latham's appliance, this experiment is designed to detect activity of osteoblasts in the maxillary sutures of Wistar rats with bilateral artificial cleft palate by immunohistochemistry technique, and evaluate the effects of this appliance on the growth and development of the maxilla.

METHODS

The animal models of male infant Wistar rats with bilateral cleft palate were made by removing some palatal bones, splitting a "V" gap of 1.5 cm wide at the line between premaxilla and segments of maxilla. A sort of appliances, which could be fixed in the mouth of Wistar rats with bilateral cleft palate for correcting protrusion premaxilla was constructed basing on the principle of Latham's appliance. Then the diferent pathological changes of osteoblast proliferation between the experimental group and the two controlled groups were examined. The jugomaxillary sutrues, temporomalar sutures and sphenoipalatine suture were harvested 7, 14 days after premaxillar orthopedic treatment, followed by 4% paraformaldehyde fixing about 1 hour, demineralization with 15% EDTA and 0.5% paraformaldehyde for 48 hours, distilled water washing for a night, dimethylbenzene transparant dealing, and paraffin wax embeding. Proliferating Osteoblasts in all these sutures were investigated using immunohiostochemical technique with monoclonal antibodies of proliferating cell nuclear antigen (PCNA).

RESULTS

Seven days after orthopedic treatment, no significant difference was observed between the experimental group and the two controlled groups. While after fourteen days, obvious PCNA-positive expression were observed in cells of all these sutures of the experimental group.

CONCLUSION

The distribution of proliferating cells and the degree of cell proliferation change after premaxillary orthopedic treatment. And significant cell proliferation is observed in the experimental group, but there are no significant differences between the two controlled groups.

Cardiac L-type calcium channel alpha 1-subunit is increased by cyclic adenosine monophosphate: messenger RNA and protein expression in intact bone

L-type calcium channels have been identified previously in both osteoblast-like osteosarcoma cell lines and primary cultures of osteoblasts using numerous techniques such as patch clamp recording, drug inhibited 45Ca2+ uptake, and Fura-2 measurements, but intact bone has not been investigated. Using reverse-transcription polymerase chain reaction (RT-PCR) we found that the three major isoforms of the alpha 1-subunit of L-type calcium channels, (alpha 1C, alpha 1D, and alpha 1S) are present in RNA extracted from ROS 17/2.8 osteosarcoma cells, rat femur, and rat skull. Sequencing of most of the alpha 1C-subunit from rat femur and ROS cells revealed that the splice variants in osteosarcoma cells and intact bone differ, but there are no unique sequence variations compared with those found in other tissues. Northern blot analysis of ROS cell RNA indicated that cyclic adenosine monophosphate (cAMP), but not 1 alpha, 25-dihydroxyvitamin D3, increased the messenger RNA (mRNA) of the alpha 1C-subunit. Western blot of ROS cell lysates revealed a band of more then 220 kDa, the amount of which increased in cells treated with cAMP. Using confocal microscopy combined with immunohistochemistry in ROS cells, intact bone, and cartilage, we found that the alpha 1C-subunit of this channel is expressed in osteoblasts and chondrocytes suggesting this channel may be a pathway for signal transduction in intact tissue, because it is in osteosarcoma cell lines and primary osteoblasts grown in tissue culture.

[Antitumor effect of radiation combined with tumor draining lymphocytes on human ACC-M cell in vitro]

OBJECTIVE

To find whether there is any synergistic effect of radiation combined with interleukin-2(IL-2) activated tumor draining lymph nodes lymphocytes (DNL) from oral-carcinoma patients on high-lung metastatic salivary adenoid cystic carcinoma cell line(ACC-M).

METHODS

Colony-forming test was used to investigate antitumor effect and analyzed using linear-quadratic(LQ) equation and single hit multi targets equation.

RESULTS

The ratio of effect to targets was 25:1. The cytotoxicity of DNL was 49.06%. Radiation combined with DNL showed higher antitumor activity compared with radiation alone, alpha value, Dq and S2 were 0.7688 and 0.342 0; 1.5901 and 0.5995; 0.4481 and 0.1135 respectively(P < 0.05).

CONCLUSIONS

It indicates that in initial region of survival curve, DNL significantly increased sublethal damage on ACC-M.

[The orthognathic treatment of developmental mandibular asymmetry]

OBJECTIVE

To explore the methods of orthognathic treatment for the developmental mandibular asymmetry to simultaneously achieve satisfactory facial appearance and oral functions and to prevent recurrence of the deformity.

METHODS

37 cases of developmental mandibular asymmetry have been treated in past seven years. The type of the deformity, the management of the cases, and the effects of therapy were summarized in this paper.

RESULTS

According to the type of the asymmetric deformity, different means were used. After treatment, all the patients obtained satisfactory facial appearance and oral function.

CONCLUSIONS

During the orthognathic treatment, it is important to simultaneously ameliorate facial appearance and achieve good oral function. It should be diagnosed before surgery whether the development of the deformity is steady or not. The correction of skeleton and soft tissues must be performed by stages.

Opposite effects of pressurized steady versus pulsatile perfusion on vascular endothelial cell cytosolic pH: role of tyrosine kinase and mitogen-activated protein kinase signaling

Endothelial cytosolic pH (pH(i)) modulates ion channel function, vascular tone, and cell proliferation. Steady shear induces rapid acidification in bicarbonate buffer. However, in vivo shear is typically pulsatile, potentially altering this response. We tested effects and mechanisms of pH(i) modulation by flow pulsatility, comparing pressurized steady versus pulse-flow responses in bovine aortic endothelial cells cultured within glass capillary tubes. Cells were loaded with the fluorescent pH(i) indicator carboxy seminaphthorhodafluor-1 and perfused with physiological pulsatile pressure and flow generated by a custom servo-control system. Raising mean pressure from 0 to 90 mm Hg at 0.5 mL/min steady flow in bicarbonate buffer induced sustained acidification (-0.33+/-0.09 pH units, P<0.01). A subsequent increase in steady flow resulted in further acidification. In contrast, if mean pressure and flow were unchanged but perfusion made pulsatile, pH(i) rose +0.3+/-0.03 (P<0. 0001) over 30 to 60 minutes. HCO(3)(-) removal and use of acid/base exchange inhibitors 5-(N-ethyl-N-isopropyl)amiloride or diisothiocyanato stilbene disulfonic acid identified both extracellular Na(+)-independent Cl(-)-HCO(3)(-) and Na(+)-H(+) exchangers as activated by static pressure, whereas pulsatility activated extracellular Na(+)-dependent Cl(-)-HCO(3)(-) and Na(+)-H(+) exchangers to raise pH(i). Pulse-perfusion alkalinization occurred with or without flow reversal and increased 1.6-fold in Ca(2+)-free buffer. Inhibition of c-Src tyrosine kinase (4-amino-5-[4-chlorophenyl]-7-[t-butyl]pyrazolo [3,4-d]pyrimidine; PP2) or MEK-1 (mitogen-activated protein kinase [MAP]/extracellular signal-regulated kinase [ERK]-1) (PD98059, blocking ERK1/2) blocked or reversed the pulsatile-flow pH(i) change to acidification. In contrast, PP2 had no effect on steady flow acidification, whereas MEK-1 inhibition converted it to alkalinization. Thus, pulsatile and steady flow trigger opposite effects on endothelial pH(i) by differential activation of acid/base exchangers linked to c-Src and MAP kinase phosphorylation, but not to Ca(2+). These data highlight specific signaling responses triggered by phasic shear profiles.

[Cephalometrical analysis of effects of premaxillary orthopedic treatment on maxillary growth of Wistar rats with bilateral artificial cleft palate]

OBJECTIVE

To measure the differences between the experimental group and the two controlled groups by using the cephalometric radiography technique to study the effects of premaxillary orthopedic treatments on the growth and development of maxilla.

METHODS

To make an animal model with bilateral cleft palate by surgery operation: General anesthesia was carried on by injecting 2.5% pentobarbital (25 mg/kg) into abdominal cavity, then almost the same bone of rats' palate were removed from bilateral palate. An appliance, based on the principle of Latham's appliance was made and designed for premaxillary orthopedic treatment. It was fixed in rats' palate using pins under the condition of general anesthesia. After 20 days of orthopedic treatment, the rats were anesthetized by ether, and cephalometric films were taken under self-designed cephalometer and analysed aided by computer.

RESULTS

The distances that represented the maxillary position in the posterior-anterior (PA) direction significantly increased (P < 0.05), while the angles that represented the direction of premaxillary growth significantly decreased (P < 0.05) between the experimental group and the two controlled groups. There were no significant difference between the two controlled groups.

CONCLUSION

Premaxilla of rats can be effectively moved backward and rotated downward and backward on the PA direction by appliance. The appliance can move the segment palate forward during the premaxillary backword. The appliance can stimulate maxillary growth.

[A prospective study on etiologic bacteria in 200 patients with pneumonia]

The etiologic agents in 200 patients with pneumonia were studied by the bacterial culture of sputums obtained from the protected single catheter brush or quantitative expectoration at one morning or three-morning expectoration. Two hundred patients were divided into 3 groups. Group 1 was Nosocomial pneumonia (NP patients). Group 2-1 and Group 2-2 were community acquired pneumonia (CAP patients). All cases in Group 1 and Group 2-2 suffered from significant underlying diseases while Group 2-1 did not. Gram-negative bacilli(GNB) were isolated from the specimens in Group 1 (87%) and Group 2-2 (75%), respectively. Pseudomonas (30.8%) and klebsiella (20.5%) were the predominant bacteria (in Group 1 and pseudomonas bacteria) in Group 1 and pseudomonas (27.3%), acinetobacter (23%) and kledsiella (18%) were the major etiologic agents in Group 2-2. The commonest pathogens in Group 2-1 were gram-positive cocci (75%), in which streptococcus (38%) and staphylococcus aureus (25%) were the dominant agents. Compared with Group 2, Group 1 suffered from more mixed bacteria and the agents presented severer drug-resistant. The prognosis was worse in Group 2-2 than in Group 2-1. The results showed that the GNB pneumonia was more common in the cases who had underlying disease, no matter whether the pneumonia was NP or CAP. These patients had more trouble on their antibiotic therapy. Thus it is important that doctors should use vigorous antibiotics timely while treating these patients' underying diseases.

In vitro- and in vivo-generated defective RNAs of satellite panicum mosaic virus define cis-acting RNA elements required for replication and movement

Satellite panicum mosaic virus (SPMV) depends on its helper virus, panicum mosaic virus (PMV), to provide trans-acting proteins for replication and movement. The 824-nucleotide (nt) genome of SPMV possesses an open reading frame encoding a 17.5-kDa capsid protein (CP), which is shown to be dispensable for SPMV replication. To localize cis-acting RNA elements required for replication and movement, a comprehensive set of SPMV cDNA deletion mutants was generated. The results showed that the 263-nt 3' untranslated region (UTR) plus 73 nt upstream of the CP stop codon and the first 16 nt in the 5' UTR are required for SPMV RNA amplification and/or systemic spread. A region from nt 17 to 67 within the 5' UTR may have an accessory role in RNA accumulation, and a fragment bracketing nt 68 to 104 appears to be involved in the systemic movement of SPMV RNA in a host-dependent manner. Unexpectedly, defective RNAs (D-RNAs) accumulated de novo in millet plants coinfected with PMV and either of two SPMV mutants: SPMV-91, which is incapable of expressing the 17.5-kDa CP, and SPMV-GUG, which expresses low levels of the 17.5-kDa CP. The D-RNA derived from SPMV-91 was isolated from infected plants and used as a template to generate a cDNA clone. RNA transcripts derived from this 399-nt cDNA replicated and moved in millet plants coinoculated with PMV. The characterization of this D-RNA provided a biological confirmation that the critical RNA domains identified by the reverse genetic strategy are essential for SPMV replication and movement. The results additionally suggest that a potential "trigger" for spontaneous D-RNA accumulation may be associated with the absence or reduced accumulation of the 17.5-kDa SPMV CP. This represents the first report of a D-RNA associated with a satellite virus.

Cyclic nucleotide-gated cation channels mediate sodium and calcium influx in rat colon

We found mRNA for the three isoforms of the cyclic nucleotide-gated nonselective cation channel expressed in the mucosal layer of the rat intestine from the duodenum to the colon and in intestinal epithelial cell lines in culture. Because these channels are permeable to sodium and calcium and are stimulated by cGMP or cAMP, we measured 8-bromo-cGMP-stimulated sodium-mediated short-circuit current (I(sc)) in proximal and distal colon and unidirectional (45)Ca(2+) fluxes in proximal colon to determine whether these channels could mediate transepithelial sodium and calcium absorption across the colon. Sodium-mediated I(sc), stimulated by 8-bromo-cGMP, were inhibited by dichlorobenzamil and l-cis-diltiazem, blockers of cyclic nucleotide-gated cation channels, suggesting that these ion channels can mediate transepithelial sodium absorption. Sodium-mediated I(sc) and net transepithelial (45)Ca(2+) absorption were stimulated by heat-stable toxin from Escherichia coli that increases cGMP. Addition of l-cis-diltiazem inhibited the enhanced transepithelial absorption of both ions. These results suggest that cyclic nucleotide-gated cation channels simultaneously increase net sodium and calcium absorption in the colon of the rat.

[Diagnosis and treatment of internal jugular phlebectasia (three cases report]

OBJECTIVE

To discuss the diagnosis and treatment of patients with rare abnormal veins: the internal jugular phlebectasia.

METHODS

Three patients with swollen during straining or crying were diagnosed as internal jugular vein dilatation by ultra-sonography, DSA and MRI. Then an operation of envelopment of the right internal jugular vein with the sternocleidomastoid muscle was performed in two cases. In the third case, the bilateral internal jugular ectasia, the right internal jugular vein were resected and the left internal jugular vein was enveloped with the resected vein.

RESULTS

These three patients were treated satisfactorily by operation, and no recurrence in the following two years.

CONCLUSION

To those who want their internal jugular phlebectasia to be treated, the operation of envelopment of internal jugular vein with sternocleidomastoid muscle is a good method.

Tomato Spotted Wilt Tospovirus Adapts to the TSWV N Gene-Derived Resistance by Genome Reassortment

ABSTRACT Pathogen- and host-derived resistance have been shown to suppress infection by many plant viruses. Tomato spotted wilt tospovirus (TSWV) is among these systems; however, it has easily overcome nearly all host resistance genes and has recently been shown to overcome resistance mediated by the TSWV N gene. To better understand the resistance-breaking mechanisms, we have chosen TSWV N gene-derived resistance (TNDR) as a model to study how plant viruses defeat resistance genes. A defined viral population of isolates TSWV-D and TSWV-10, both suppressed by TNDR, was subjected to TNDR selection by serial passage in an N-gene transgenic plant. The genotype analysis demonstrated that the mixed viral population was driven to form a specific reassortant, L(10)M(10)S(D), in the presence of TNDR selection, but remained as a heterogeneous mixture in the absence of the selection. A genotype assay of 120 local lesion isolates from the first, fourth, and seventh transfers confirmed the shift of genomic composition. Further analysis demonstrated that the individual L(10), M(10), and S(D) RNA segments were each selected independently in response to TNDR selection rather than to a mutation or recombination event. Following the seventh transfer on the N-gene transgenic plants, TSWV S RNA remained essentially identical to the S RNA from TSWV-D, indicating that no intermolecular recombination occurred between the two S RNAs from TSWV-10 and TSWV-D nor with the transferred N gene. These results support the hypothesis that TSWV utilizes genome reassortment to adapt to new host genotypes rapidly and that elements from two or more segments of the genome are involved in suppression of the resistance reaction.

[Influence of radiotherapy on reconstruction flaps in oral and maxillofacial regions]

OBJECTIVE

To evaluate the influence of radiotherapy on reconstruction flaps in oral and maxillofacial regions and the radiation tolerance of flaps, and therefore provide clinical information for perioperative radiotherapy.

METHODS

Sixty-six free flaps and 22 pedicled flaps were used in the reconstruction of oral and maxillofacial tumor defects. The success and healing of the total 88 reconstruction flaps(14 flaps in preoperative radiation group and 74 flaps in postoperative radiation group) were observed. The acute and late side effects of radiotherapy in the flaps of the postoperative group were studied as well.

RESULTS

Of the preoperative 14 flaps, 12 were successful (85.7%), one partially successful and one failed. Of the postoperative 74 flaps, however, 73 were successful (98.6%) and only one partially successful. No total loss of the flap was noted in the postoperative group. The success and healing rates in the preoperative group were lower than those in the postoperative group significantly (P < 0.01-0.05). The rate of acute radiation response of flaps in the postoperative group was significantly lower than that in the surrounding normal tissues(35.1% versus 83.8%, P < 0.01). The late side effects of radiotherapy were rare. The radiation tolerance in different kinds of flaps was similar.

CONCLUSION

Reconstruction flaps in oral and maxillofacial regions have a good radiation tolerance and routine postoperative radiation doses can be safely delivered.

Monoclonal antibodies that inhibit the transport function of the 190-kDa multidrug resistance protein, MRP. Localization of their epitopes to the nucleotide-binding domains of the protein

Multidrug resistance in tumor cells is often accompanied by overexpression of multidrug resistance protein (MRP), a 190-kDa transmembrane protein that belongs to the ATP-binding cassette superfamily of transport proteins. MRP mediates ATP-dependent transport of a variety of conjugated organic anions and can also transport several unmodified xenobiotics in a glutathione-dependent manner. To facilitate structure-function studies of MRP, we have generated a panel of MRP-specific monoclonal antibodies (mAbs). Four of these mAbs, QCRL-2, -3, -4, and -6, bind intracellular conformation-dependent epitopes, and we have shown that they can inhibit the transport of several MRP substrates. Binding competition and immunoprecipitation assays indicated that mAbs QCRL-4 and -6 probably recognize the same detergent-sensitive epitope in MRP, whereas mAbs QCRL-2, -3, and -4 each bind distinct, non-overlapping epitopes. Fab fragments inhibit transport as effectively as the intact mAbs, suggesting that inhibition results from direct interactions of the mAbs with MRP. Immunodot blot and immunoprecipitation analyses revealed that the minimal regions of MRP sufficient for full reactivity of mAbs QCRL-2 and -3 are amino acids 617-858 and 617-932, respectively, which encompass the NH2-proximal nucleotide-binding domain (NBD). In contrast, the epitope bound by mAb QCRL-4 localized to amino acids 1294-1531, a region that contains the COOH-proximal NBD. However, none of the mAbs inhibited photolabeling of intact MRP with 8-azido-[alpha-32P]ATP. This suggests that rather than preventing nucleotide binding, the mAbs inhibit transport by interfering with substrate binding or by trapping MRP in a conformation that does not allow transport to occur. Our results also demonstrate for the first time that the NBDs of MRP can be expressed as soluble polypeptides that retain a native conformation.

[Craniofacial resection for advanced malignant tumors in oral and maxillofacial region]

OBJECTIVE

To investigate the clinical significance of craniofacial resection for advanced malignant tumors of OMS region.

METHODS

Forty-six patients underwent craniofacial resection for malignancies involving the anterior and middle cranial fossa over a 20-year period between June 1978 and December 1997 in our department were evaluated. The extents of cranial resections were anterior cranial fossa in 20 cases, middle crania fossa in 16 cases and anterior and middle skull base in 10 cases. There were 18 patients undergoing orbital exenteration simultaneously. 14 cases had limitted dura resected because of dural involvement.

RESULTS

The survival rate at 3 and 5 years was 48.8% (20/41) and 35.1% (13/37), respectively. The survival rate at 10 years was 20.0% (4/20).

CONCLUSION

Our results revealed a considerably fine prospect of craniofacial resection for patients with advanced malignancies in oral and maxillofacial region.

Two non-reactive ternary complexes of estrogenic 17beta-hydroxysteroid dehydrogenase: crystallization and preliminary structural analysis

Human estrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD1, EC1.1.1.62) is an important enzyme that catalyses the last step of active estrogen formation. 17Beta-HSD1 plays a key role in the proliferation of breast cancer cells. The three-dimensional structures of this enzyme and of the enzyme-estradiol complex have been solved (Zhu et al., 1993, J. Mol. Biol. 234:242; Ghosh et al., 1995, Structure 3:503; Azzi et al., 1996, Nature Struct. Biol. 3:665). The determination of the non-reactive ternary complex structure, which could mimic the transition state, constitutes a further critical step toward the rational design of inhibitors for this enzyme (Ghosh et al. 1995, Structure 3:503; Penning, 1996, Endocrine-Related Cancer, 3:41). To further study the transition state, two non-reactive ternary complexes, 17beta-HSD1-EM519-NADP+ and 17beta-HSD1-EM553-NADP+ were crystallized using combined methods of soaking and co-crystallization. Although they belong to the same C2 space group, they have different unit cells, with a = 155.59 A, b = 42.82 A, c = 121.15 A, beta = 128.5 degrees for 17beta-HSD1-EM519-NADP+, and a = 124.01 A, b = 45.16 A, c = 61.40 A, beta = 99.2 degrees for 17beta-HSD1-EM553-NADP+, respectively. Our preliminary results revealed that the inhibitors interact differently with the enzyme than do the natural substrates.

Selection of quantitative criteria for evaluating metastases of a highly metastatic salivary adenoid cystic carcinoma cell line to the lungs of nude mice

OBJECTIVE

To select reliable quantitative criteria for evaluating metastases of a highly metastatic salivary adenoid cystic carcinoma cell line (ACC-M) cell to the lungs of nude mice.

MATERIALS AND METHODS

The within-group coefficients of correlation of 5 parameters were measured from lung slides using a video image digital analysis system (VIDAS), and the intergroup coefficients of correlation of 6 sets of parameters from all the lungs, which were taken from ACC-M lung metastases models, were calculated and statistically analyzed.

RESULTS

The within-group coefficients of correlation of 5 parameters are as follows: ratio of area of metastases, t = 0.9 (P < 0.001); area of metastases, t = 0.7 (P < 0.05), size of lung section, numbers of metastases, and size of the largest metastatic focus all t < 0.4 (P > 0.05). The intergroup coefficients of correlation of the parameters are as follows: ratio of area of metastases was assigned 1, weight of the lung was 0.9755, and area of metastases was 0.8628.

CONCLUSION

For evaluating lung metastases of ACC-M, the ratio of area of metastases and weight of the lung are precise; the area of metastases is also significant within the 6 quantitative parameters.