Novel chromophores and buried charges control color in mFruits

mFruits are second-generation monomeric red fluorescent proteins (mRFPs) that have improved brightness and photostability compared to the first-generation mRFP1. The emission and excitation maxima are distributed over the remarkably large ranges of about 550-650 and 540-590 nm, respectively; however, the variations in the spectra can be traced to a few key amino acids. Spectroscopic and atomic resolution crystallographic analyses of three representatives, mOrange, mStrawberry, and mCherry, reveal that different mechanisms operate to establish the excitation and emission maxima. Evidently, they all undergo the second oxidation step to produce an acylimine linkage in the polypeptide backbone. In comparison to the progenitor DsRed, direct covalent modification to this linkage (mOrange) and indirect modification of the chromophore environment (mStrawberry and mCherry) produce strong blue- and red-shifted variants. The blue shift of mOrange is induced by an unprecedented covalent modification of the protein backbone. The electron-density map indicates the formation of a third heterocycle, 2-hydroxy-dihydrooxazole, upon the reaction of Thr 66 Ogamma with the polypeptide backbone, which in turn reduces the conjugation of the carbonyl at position 65 with the rest of the chromophore. In mStrawberry and mCherry, the movement of charged Lys 70 and protonation of Glu 215 are proposed to modify the chromophore electron-density distribution, inducing the red shift. pH-dependent spectral shifts of mCherry and mStrawberry appear to result from the titration of Glu 215, although, for mStrawberry, partial cyclization of Thr 66 may contribute at high pH.

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution†,‡

When the nonfluorescent chromoprotein asFP595 from Anemonia sulcata is subjected to sufficiently intense illumination near the absorbance maximum (lambda(abs)(max) = 568 nm), it undergoes a remarkable transition, termed "kindling", to a long-lived fluorescent state (lambda(em)(max) = 595 nm). In the dark recovery phase, the kindled state relaxes thermally on a time scale of seconds or can instantly be reverted upon illumination at 450 nm. The kindling phenomenon is enhanced by the Ala143 --> Gly point mutation, which slows the dark recovery time constant to 100 s at room temperature and increases the fluorescence quantum yield. To investigate the chemical nature of the chromophore and the possible role of chromophore isomerization in the kindling phenomenon, we determined the crystal structure of the "kindling fluorescent protein" asFP595-A143G (KFP) in the dark-adapted state at 1.38 A resolution and 100 K. The chromophore, derived from the Met63-Tyr64-Gly65 tripeptide, closely resembles that of the nonfluorescent chromoprotein Rtms5 in that the configuration is trans about the methylene bridge and there is substantial distortion from planarity. Unlike in Rtms5, in the native protein the polypeptide backbone is cleaved between Cys62 and Met63. The size and shape of the chromophore pocket suggest that the cis isomer of the chromophore could also be accommodated. Within the pocket, partially disordered His197 displays two conformations, which may constitute a binary switch that stabilizes different chromophore configurations. The energy barrier for thermal relaxation was found by Arrhenius plot analysis to be approximately 71 kJ/mol, somewhat higher than the value of approximately 55 kJ/mol observed for cis-trans isomerization of a model chromophore in solution.

RPGR ORF15 isoform co-localizes with RPGRIP1 at centrioles and basal bodies and interacts with nucleophosmin

The ORF15 isoform of RPGR (RPGR(ORF15)) and RPGR interacting protein 1 (RPGRIP1) are mutated in a variety of retinal dystrophies but their functions are poorly understood. Here, we show that in cultured mammalian cells both RPGR(ORF15) and RPGRIP1 localize to centrioles. These localizations are resistant to the microtubule destabilizing drug nocodazole and persist throughout the cell cycle. RPGR and RPGRIP1 also co-localize at basal bodies in cells with primary cilia. The C-terminal (C2) domain of RPGR(ORF15) (ORF15(C2)) is highly conserved across 13 mammalian species, suggesting that it is a functionally important domain. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, we show that this domain interacts with a 40 kDa shuttling protein nucleophosmin (NPM). The RPGR(ORF15)-NPM interaction was confirmed by (i) yeast two-hybrid analyses; (ii) binding of both recombinant and native HeLa cell NPM to RPGR(ORF15) fusion proteins in vitro; (iii) co-immunoprecipitation of native NPM, RPGR(ORF15) and RPGRIP1 from bovine retinal extracts and of native HeLa cell NPM and transfected RPGR(ORF15) from cultured cells and (iv) co-localization of NPM and RPGR(ORF15) at metaphase centrosomes in cultured cells. NPM is a multifunctional protein chaperone that shuttles between the nucleoli and the cytoplasm and has been associated with licensing of centrosomal division. RPGR and RPGRIP1 join a growing number of centrosomal proteins involved in human disease.

[Evaluation of therapeutic efficacy by detection of specific IgG and IgG4 against KLH in schistosomiasis japonica]

The specific IgG and IgG4 antibodies in the sera of patients with Schistosoma japonicum were determined by KLH-ELISA and SEA-ELISA. The results showed that KLH-ELISA was as sensitive and specific as SEA-ELISA. The negative conversion rates of IgG and IgG4 12 months after treatment detected by KLH-ELISA were significantly higher than those by SEA-ELISA. The negative conversion rate of IgG was 92.9%, and that of IgG4 was 97.6% 24 months after treatment. Therefore, it is regarded that detecting specific IgG and IgG4 by KLH has high value in both diagnosing schistosomiasis japonica and assessing its therapeutic efficacy. Particularly the specific IgG4 may be a short-duration antibody which can indicate successful chemotherapy of patients with chronic Schistosoma japonicum infection.

[Schistosoma japonicum: protective immunity induced in mice immunized with SjGST-Sj32]

Schistosoma japonicum glutathione-s-transferase (SjGST), Schistosoma japonicum 32,000 protein (Sj32) and SjGST - Sj32 were expressed and purified to study on protective immunity against Schistosoma japonicum. The result showed that compared with the adjuvant control group, the worm burden was decreased significantly in mice immunized with recombinant SjGST - Sj32, Sj32 and Sj32 + SjGST (P < 0.05). At the same time, the liver egg per gram(EPG) was decreased in mice immunized with SjGST - Sj32, Sj32, Sj32 + SjGST and SjGST. It is concluded that Sj32 significantly induces both protective immunity and anti-fecundity immunity, but SjGST only has an anti-fecundity effect.

Acute sensitization by NGF of the response of small-diameter sensory neurons to capsaicin

We investigated acute sensitization by nerve growth factor (NGF) of the response of small-diameter (<30 microm) dissociated dorsal root ganglion (DRG) cells to brief repeated puffs of capsaicin as a model for thermal hyperalgesia induced by NGF. We have previously shown that placing NGF in the bath after an initial puff of capsaicin can completely overcome the tachyphylaxis normally observed in response to a second puff 10 min later, and this response is often substantially larger than the first. If tachyphylaxis is abolished by carrying out the experiment in Ca2+-free solution, NGF still elicits potentiation of the second puff. However, the amount of potentiation is considerably less than that observed when tachyphylaxis also takes place. Thus it is concluded that NGF has two effects: overcoming tachyphylaxis and potentiation. With three puffs of capsaicin separated by 10 min, we have found that the potentiation established after 10 min exposure to NGF is no longer evident 10 min after removal of NGF. In Ca2+-free solution the potentiation can last up to 1 h after removal of NGF. These results suggest that the initial behavioral sensitization elicited by NGF could result from a direct effect on the sensory neuron but that its later components most likely involve other mechanisms. We have also investigated the contribution of various second-messenger pathways in these actions of NGF by treating the cells with blockers of MAP kinase (PD98059), protein kinase A (PKA; PKAI14-22, H89), and PKC (Bisindolylmaleimide I). Surprisingly, PD98059, which previously has been shown to diminish the enhancement of capsaicin responses of dissociated neurons when exposed to NGF for several days, had no effect on the acute response to NGF; nor did the PKC inhibitor. However, PKA inhibitors reduced the capsaicin response of the cells to NGF (as determined from the NGF effect on tachyphylaxis). Consistent with these findings we confirmed that forskolin, a PKA activator, enhances the effect of NGF on the capsaicin response. The percentage of small cells sensitized by NGF under these conditions, as determined by its ability to reduce tachyphylaxis, was 64%. This suggests that about two-thirds of DRG cells <30 microm and sensitive to capsaicin express a functional trkA receptor.

[Pathological changes between HBeAg and anti-HBe in patients with chronic hepatitis B]

OBJECTIVE

To observe the differences of pathological changes between HBeAg and anti-HBe in chronic hepatitis B.

METHODS

Liver biopsy was performed in patients with chronic hepatitis B. The histopathological grading and staging were carried out. Serum markers of viral hepatitis were tested.

RESULTS

(1) The histopathological grading and staging were closely correlated with the appearance of serum HBeAg and anti-HBe. The number of G(3-4) and S(3-4) in anti-HBe cases was significantly higher than that of G(1-2) and S(1-2), respectively. The number of G(1-2) and S(1-2) in HBeAg cases was significantly higher than that of G(3-4) and S(3-4), respectively. Significant differences were found between the group of anti-HBe cases and the group of HBeAg cases (P<0.005). (2) HBV DNA was detected in 126 of 151 HBeAg positive patients (83.4%), and the positive rate of HBV DNA in anti-HBe positive patient was 29% only.

CONCLUSIONS

(1) Severe inflammatory, necrosis and fibrosis of hepatic tissue are observed in patients with anti-HBe positive chronic hepatitis B. (2) Although HBV DNA is positively correlated to HBeAg, HBV-DNA can be detected in part of anti-HBe positive patients.

Sensitivity characteristics near the dispersion turning points of long-period fiber gratings in B/Ge codoped fiber

We report a theoretical and experimental investigation of the dispersion property of long-period fiber gratings in B/Ge codoped fiber. A novel concept of a mode ultrasensitive zone defined by a region in which the phase-matching conditions are close to the dispersion turning points is proposed. The transition from a dual-resonance state to a dispersion turning point is revealed for a set of ultrasensitive-zone gratings during the UV-writing process. We explore the sensitivity characteristics near the dispersion turning points, with the aim of implementing two types of temperature sensor with sensitivity 2 orders of magnitude higher than that of the conventional long-period gratings.

Sampled fiber Bragg grating for simultaneous refractive-index and temperature measurement

We present a novel scheme for simultaneous measurement of temperature and refractive index by use of a single sampled fiber Bragg grating (SFBG). The intrinsic nature of a SFBG that possesses both fiber Bragg grating and long-period grating spectral responses permits the temperature effect to the measured solely from the former, whereas the refractive-index information is extracted from the latter. Using such a dual-parameter sensor, we successfully demonstrated measurement of the dependence on temperature of the refractive index of an aqueous solution of sucrose.

[Schistosoma japonicum: purification and diagnostic application of recombinant 32 kD antigen]

Separation and purification of rSj32 were carried out with SDS-PAGE and electroelution technique. The purified rSj32, AWA and SEA were used to examine sera of patients with schistosomiasis, healthy individuals and patients with other parasitic diseases by ELISA. The results showed that the molecule weight of rSj32 was 37 kD. The sensitivity and specificity of rSj32 as a coating antigen in ELISA were as good as those of AWA and SEA. It is suggested that rSj32 antigen is a potential antigen for immunodiagnosis of schistosomiasis japonica.

[Characterization of cefoperazone resistance gene on plasmid pFC in E. coli HX88108]

OBJECTIVE

To investigate the characterization of cefoperazone resistance gene (CPZr) on plasmid pFC in E. coli HX88108 and inquire into the mechanism of resistance to CPZ at the molecular level.

METHODS

E. coli HX88108 strain which demonstrated high-level resistance to cefoperazone (MIC, > 512 micrograms/ml) was isolated from a severely infected patient in 1988. Five plasmids coexisting in the strain were designated pFC, pFT1; pFT2, pFT3 and pFX, respectively. Four plasmids except pFX conferred CPZ resistance. Cefoperazone resistance gene (CPZr) has been cloned from plasmid pFC. beta-lactamase assays with Nitrocefin were performed.

RESULTS

The expression product of CPZr was beta-lactamase. The high level beta-lactamase enzymatic activities against cephaloridine of CPZr transformants which were detected spectrophotometrically at 260 nm wave length demonstrated high level similarities to that of pFC. MICs of 18 antibiotics were determined according to a guideline of NCCLS by broth dilution method. CPZr transformants showed moderate level resistance to ampicillin, cefazolin, cefazolin, cefamandole and CPZ (MIC, 64 micrograms/ml). Meanwhile, susceptibility testing results demonstrated that the level of resistance to CPZ of pFC transformant in this study (MIC, 64 micrograms/ml) was much lower than that in 1988 (MIC, > 512 micrograms/ml) and resistance to nofloxacin and aminoglycosides was not observed. Induction experiment and temperature-sensitive mutation of CPZ resistance were performed. CPZr colonal strains revealed the higher-level of resistance to CPZ (MIC, 512 micrograms/ml) due to antibiotic CPZ induction rather than temperature sensitive mutation.

CONCLUSION

This observation suggests that resistance to antibiotics encoded by plasmid might have been lower or lost under no antibiotic stress in a certain period, but higher under heavy stress.

Control of intramolecular interactions between the pleckstrin homology and Dbl homology domains of Vav and Sos1 regulates Rac binding

Vav and Sos1 are Dbl family guanine nucleotide exchange factors, which activate Rho family GTPases in response to phosphatidylinositol 3-kinase products. A pleckstrin homology domain adjacent to the catalytic Dbl homology domain via an unknown mechanism mediates the effects of phosphoinositides on guanine nucleotide exchange activity. Here we tested the possibility that phosphatidylinositol 3-kinase substrates and products control an interaction between the pleckstrin homology domain and the Dbl homology domain, thereby explaining the inhibitory effects of phosphatidylinositol 3-kinase substrates and stimulatory effects of the products. Binding studies using isolated fragments of Vav and Sos indicate phosphatidylinositol 3-kinase substrate promotes the binding of the pleckstrin homology domain to the Dbl homology domain and blocks Rac binding to the DH domain, whereas phosphatidylinositol 3-kinase products disrupt the Dbl homology/pleckstrin homology interactions and permit Rac binding. Additionally, Lck phosphorylation of Vav, a known activating event, reduces the affinities between the Vav Dbl homology and pleckstrin homology domains and permits Rac binding. We also show Vav activation in cells, as monitored by phosphorylation of Vav, Vav association with phosphatidylinositol 3,4,5-trisphosphate, and Vav guanine nucleotide exchange activity, is blocked by the phosphatidylinositol 3-kinase inhibitor wortmannin. These results suggest the molecular mechanisms for activation of Vav and Sos1 require disruption of inhibitory intramolecular interactions involving the pleckstrin homology and Dbl homology domains.

[Stress-corrosion test of laser welded ceramic alloys]

OBJECTIVE

The corrosion properties of dental material are very critical. This study is to investigate the corrosion properties of laser welded basemetalalloys.

METHODS

The precise stainless rod molds had been made in size of phi 3 mm x 4 mm, with which 20 wax patterns were made. They were invested with inner investment (Bellavest) and outer investment (phosphate and gypsum). Then they were casted with CW-PA (Ni-Cr-Nb) alloys. All casted alloy rods were ultra-sonic washed in distilled water. Every two rods were contacted longitudinally by a special welding jig. Laser welding machine (DL-2002) was used to weld them at 305 V, 20 ms. The specimens were divided into 2 groups as following: 1. The group of stress-corrosion: 5 laser welded samples were subjected to the stress-corrosion test under 261.44 MPa in the 37 degrees C artificial saliva for 3 months in a special stress-corrosion test jig. After that, the ultimate tensile strength (UTS) was tested, the surface microcrack at the fusion zone (FZ), the heat affecting zone (HAZ) and the interface zone was observed with SEM (ARMY-1845, USA), the elements were also analyzed with EPMA (ARMY-1845, USA) at the fusion zone (FZ), the parent metal zone and the interface zone. 2. The other 5 laser welded samples were made as the controlled group. No special treatment were done to them, and the UTS was also tested, the surface of the micro crack and the elements at the FZ, the HAZ, parent metal zone and the interface zone were observed and analyzed with SEM, EPMA as well.

RESULTS

The study showed us that the UTS of the stress-corrosion group was 502.48 +/- 12.49 MPa, while that of the controlled group was 446.05 +/- 82.50 MPa, there was no significant difference (P > 0.05). There was no microcrack on any sample's surface at the FZ, the HAZ and the interface zone. The main elements of the FZ were Ni(56.63%), Cr(19.36%), Nb (6.57%), Si(6.01%), Al(0.32%) and Mo(11.11%), while the elements of the parent metal zone were Ni(60.77%), Cr (20.59%), Nb(5.03%), Si(3.95%), Al(0.37%) and Mo(9.29%) respectively.

CONCLUSION

The results suggest that the corrosion properties of laser welded alloys are excellent.

[Schistosoma japonicum ferritin: cloning, nucleotide sequencing, expression, and purification]

Our previous work showed that immunization of mice with Schistosoma japonicum (Sj) immature eggs induced significant immunity against fecundity and embryonation of the parasite. The Sj adult cDNA library was screened by sera from rabbits against Sj immature egg antigen (RASjIEA). The genes encoding molecules which may induce immunity against fecundity/embryonation were chosen for further cloning and expression. First of all, RASjIEA was absorbed with E. coli lysate to remove cross reactive antibodies. The cDNA library was then immunoscreened using the routine method. The resulted positive plaques were rescreened till individual clones were confirmed. Phagemids were obtained using in vivo excision. The positive clones were amplified using PCR. The sizes of the genes were determined by agarose gel electrophoresis. After DNA sequencing of the genes cloned, Gene bank was searched and six different genes were identified from a total of 102 positive clones. One of six identified genes, Sj ferritin (SjFer) was chosen to subclone into pGMC vector. According to DNA sequences of Sj Fer and MCS (multiple cloning site) of the vector, forward primer (Fer/GMC1) and reverse primer (Fer/GMC2) were designed and used to amplify Sj Fer by PCR. The Sj Fer cDNA and expression vector pGMC were digested with BamHI and XhoI. The digested cDNA and pGMC were ligased by T4 DNA ligase to construct a recombinant which was then used to transform E. coli strain ER2566. The fusion protein GMCSF-Sj Ferritin was expressed in insoluble form, the inclusion body. Pellets were harvested and resolved in Tris-HCl buffer containing 8M urea. GMCSF-Sj Ferritin was purified by affinity chromatography using Ni-NTA resin. The molecular weight was determined by SDS-PAGE. This study first reports the gene encoding S. japonicum ferritin as a new candidate for schistosome vaccine.

Nerve growth factor acutely sensitizes the response of adult rat sensory neurons to capsaicin

Perforated patch clamp recordings were made from 118 voltage clamped (-60 mV), capsaicin-responsive dorsal root ganglion (DRG) cells (<30 microns) maintained in dissociated cell culture (6-24 h). A second puff of capsaicin 10 min later always evoked a substantially smaller inward current than the initial puff (tachyphylaxis). Bath-application of NGF (2, 10 or 100 ng/ml) during the 10-min interval resulted in facilitation of the second response in a dose dependent manner in 67% of cells studied. NT-4/5 exerted similar effects but NT-3 did not. Ten minute pretreatment with NGF increased the initial response to capsaicin. We conclude that NGF acutely conditions the response to capsaicin via direct action on DRG cells. Since the capsaicin receptor (VR1) mediates noxious heat sensitivity of polymodal nociceptors, acute sensitization of the noxious heat response by NGF and NT-4/5 may involve a direct action on VR1.

[Sub-cloning and preliminary sequence analysis of the gene encoding of a cefoperazone hydrolyzing beta-lactamase isolated from Escherichia coli]

Escherichia coli HX88108, which is resistant to cefoperazone(CPZ), was isolated from a severely infected patient. We studied genetical basis of beta-lactamase produced in E. coli HX88108 by pFL25, one of the recombinant plasmid of pFC. Largescale pFL25 plasmid was extracted, purified, and cleaved with restriction endonuclease EcoR I, Sal I, Pvu I, then subcloned into vector pUC19 as 1.9 kb, 0.9 kb, 0.65 kb fragments respectively. Recomminant plasmids were selected by alpha-complementation and determined by restriction endonuclease analysis. DNA sequencing was performed by the dideoxy polymerase chain termination method. Partial nucleotide sequence(1-78 nucleotide position) of the gene was found to be highly homologous (97%) with the gene coding for TEM-52 extended spectrum beta-lactamase of K. pneumonise, suggesting that the beta-lactamase coded by the cefoperazone resistant gene might be derived from TEM-type beta-lactamase.

[Cloning and orientation of cefoperazone resistance gene on plasmid pFC in E. coli HX88108]

Cefoperazone resistance gene (CPZr) has been cloned from plasmid pFC of E. coli HX88108 using the vector pMB9 (TCr, 5.3 kb). The plasmid pFC DNA was partially digested with Sau3A I, and its 1-2 kb fragments were ligated into BamH I site of vector plasmid pMB9. The recombinant DNA was then transformed into E. coli DH5 prepared using calcium chloride. CPZ resistant bacterial colonies were selected on the agar SOB plates containing CPZ (40 micrograms/ml). The resistance to CPZ could be stably reserved in generation after generation. The recombinant plasmids which encoded CPZ resistance were designated pFL11, pFL25, pFL33, pFL82, pFL86 and pFL102. Rapid small-scale preparation of plasmid and DNA restrication enzyme analysis were used for identification of bacterial colonies. Five plasmids DNA physical maps have been established. Comparison of recombinant plasmids maps with pFC map confirmed that the CPZr gene was oriented between nucleotide no. 3200 bp and no. 4800 + 40 bp of plasmid pFC total sequence. Its molecular weight was about 1.6 kb. There were EcoR I, Sma I and Pvu II sites within CPZr gene.

Role of substrates and products of PI 3-kinase in regulating activation of Rac-related guanosine triphosphatases by Vav

Mitogen stimulation of cytoskeletal changes and c-jun amino-terminal kinases is mediated by Rac small guanine nucleotide-binding proteins. Vav, a guanosine diphosphate (GDP)-guanosine triphosphate (GTP) exchange factor for Rac that stimulates the exchange of bound GDP for GTP, bound to and was directly controlled by substrates and products of phosphoinositide (PI) 3-kinase. The PI 3-kinase substrate phosphatidylinositol-4,5-bisphosphate inhibited activation of Vav by the tyrosine kinase Lck, whereas the product phosphatidylinositol-3,4,5-trisphosphate enhanced phosphorylation and activation of Vav by Lck. Control of Vav in response to mitogens by the products of PI 3-kinase suggests a mechanism for Ras-dependent activation of Rac.

Regulation of endothelin production and secretion in cultured collecting duct cells by endogenous transforming growth factor-beta

Confluent cultures of two renal collecting duct cell lines (M-1 and mIMCD-K2 cells derived from cortical and inner medullary collecting ducts, respectively) express endothelin1 (ET1), transforming growth factor-beta (TGF beta; both TGF beta 1 and TGF beta 2), and both types of the TGF beta receptor. Experiments were performed to test whether endogenous TGF beta may be a paracrine modulator of ET1 expression in these cells. Treatment of M-1 and mIMCD-K2 cells with TGF beta 2 antisense oligodeoxynucleotides (ODN) significantly reduced ET1 messenger RNA (mRNA) and ET secretion (as well as TGF beta 2 mRNA) in a concentration-dependent manner, whereas control ODN were without significant effects. To produce ET inhibition, antisense ODN had to be present in the basolateral medium, whereas its sole presence in the apical medium was without effect. In addition, a pan-specific TGF beta antibody caused a significant reduction of ET1 mRNA expression and ET1 secretion. M-1 cells were found to express high levels of the mRNA for plasminogen activator of both tissue and urokinase types. Addition of the nonspecific serine protease inhibitor aprotinin (50 micrograms/ml) to the medium for 24 h significantly reduced the secretion of ET1. These results suggest that secretion of endogenous TGF beta, at least in part activated by the plasminogen/plasmin system, participates in the regulation of ET1 synthesis and secretion by collecting duct cell lines.

[Kidney reinforcing and yang supporting action of cistanche deserticola Y. C. Ma before and after preparation]

The weights of seminal vesicle and prostate gland of castrated young rats were significantly increased by administration of alcoholsoluble extract from decoction of Cistanche deserticola. The weights of testes, seminal vesicle and prostate gland in mice and rats were also increased by the extract. The phagocytic function of intra-abdominal macrophage in mice was activated by decoction of Cistanche deserticola. The results showed no statistical differences between crude and prepared drugs. The maximum oral tolerance for mouse was 40 g/kg.

Synthesis and secretion of endothelin in a cortical collecting duct cell line

Previous experiments have shown that epithelial cells in the renal medulla produce endothelin-1 (ET-1) and possess ETB receptors. It has been suggested that medullary ET-1 may affect water and sodium absorption along the collecting ducts in an autocrine fashion. To study possible mechanisms responsible for the regulation of medullary ET-1 production, experiments were performed in M-1 cells and mIMCD-K2 cells, cell lines derived from cortical and inner medullary collecting ducts of SV40 transgenic mice, grown to confluence on collagen-coated filter inserts. Both cell lines were found to express ET-1 mRNA and to secrete ET almost exclusively into the basolateral medium as long as the transepithelial resistance was high. Inhibition of transcription with actinomycin D was followed by a decline in both ET mRNA [halftime (t1/2) = 30 min] and ET secretion (t1/2 = approximately 90 min). The addition of arginine vasopressin (AVP, 10(-8) M; 2- or 4-h exposure) or incubation of M-1 cells in hypertonic media (+50 mM NaCl, 4- or 6-h exposure) did not significantly alter ET secretion or ET-1 mRNA expression. In contrast, simultaneously increasing AVP(10(-8) M in the basolateral medium) and tonicity (+50 mM NaCl) for 4 h increased ET secretion (from 28.9 +/- 3.9 to 41.8 +/- 3.8 pg.h-1.mg protein-1; P = 0.029, n = 10) and ET-1 mRNA (control = 2,138 cpm/microliter, log of 3.33 +/- 0.048, n = 4; AVP + NaCl = 3,548.1 cpm/microliter, log of 3.55 +/- 0.09; P = 0.045, n = 5). Exposure of M-1 cells to hypertonic media (+50 mM NaCl or 100 mM mannitol) for 24 h was associated with a marked reduction of ET secretion (-83.9% with NaCl and -78.4% with mannitol; P < 0.0001). This reduction was attenuated, but not prevented, by the presence of AVP in the basolateral medium (-40%). ET-1 mRNA, in contrast, did not change with 24-h exposure to hypertonic media and increased when AVP was present. Results are compatible with the concept that generation of ET by collecting duct cells may contribute in a complex and time-dependent fashion to the paracrine control of collecting duct cell function.

Relapse after non-T-cell-depleted allogeneic bone marrow transplantation for chronic myelogenous leukemia: early transplantation, use of an unrelated donor, and chronic graft-versus-host disease are protective

We analyzed the incidence of posttransplant chronic myelogenous leukemia (CML) relapse in 283 consecutive related-donor (n = 177) and unrelated-donor (n = 106) allogeneic transplant recipients. Twenty-two of 165 related-donor recipients with stable or advanced disease at the time of transplant had hematologic relapse of CML following transplant (5-year Kaplan-Meier estimate of relapse, 20%; 95% confidence interval [CI], 11 to 30%). One of 12 patients transplanted in second stable phase following blast crisis also relapsed. Fifteen related-donor transplant recipients relapsed within 5 years of transplant; however, seven relapsed between 5 and 9 years after transplant. Factors independently associated with an increased risk of posttransplant relapse for related-donor recipients included prolonged interval between diagnosis and transplant (relative risk, [RR], 3.81; P = .009) and bone marrow basophilia (RR, 5.62; P = .01). Related-donor recipients with posttransplant chronic graft-versus-host disease (CGVHD) had a decreased risk of relapse (RR, 0.24; P = .005). Only two of 106 unrelated-donor transplant recipients relapsed following transplant (5-year Kaplan-Meier estimate of relapse, 3%; 95% CI, 0% to 7%). When both related- and unrelated-donor recipients were considered, the use of an unrelated donor was independently associated with a decreased risk of relapse (RR, 0.24; P = .07). Twelve of 16 relapsing patients who received further therapy (nine of 13 who underwent second transplant and three of three who received donor leukocyte infusions) remain alive. This analysis shows that relapse, sometimes occurring long after transplant, is an important adverse outcome in allogeneic transplantation for CML. Early transplant, posttransplant CGVHD, and use of an unrelated donor are associated with a reduced incidence of relapse, perhaps due to allogeneic disparities enhancing the graft-versus-leukemia effect.

Study of spontaneous combustion coals by GC and GC-MS

Organic geochemical characteristics of 3 Chinese spontaneous combustion coals have been carried out by means of GC and GC-MS analysis. It has been observed that more compounds with low to medium carbon number, such as terpenoids and others can be found in spontaneous combustion coals than in normal samples.

Neurotransmitter and neuromodulator activity in the gustatory zone of the nucleus tractus solitarius

The rostral nucleus of the solitary tract (rNST) is the first central relay in the gustatory pathway. While previous investigations have provided a wealth of information on the pattern of central terminations of gustatory afferent fibers, the morphology of synaptic connections of rNST neurons and responses of second order neurons to taste stimuli applied to the tongue, little is known regarding the neurophysiological characteristics of synaptic transmission in rNST. We have used an in vitro brain slice preparation of the rNST to study the intrinsic biophysical properties, neuropharmacology and synaptic responses of rNST neurons. These experiments have revealed that rNST neurons respond to the excitatory amino acid neurotransmitter glutamate, as well as the inhibitory amino acid neurotransmitter gamma amino butyric acid (GABA). By use of glutamate receptor agonists and antagonists we have shown that rNST neurons have AMPA/kainate and NMDA ionotropic glutamate receptors, as well as matabotropic glutamate receptors. In addition, rNST neurons respond to both GABAA and GABAB receptor agonists. The nature of the transmission at the synapse between primary afferent fibers and second order neurons in rNST has been examined by electrical stimulation of the solitary tract to elicit post-synaptic potentials (PSP). Three types of monosynaptic PSP result from stimulation of the solitary tract: excitatory post-synaptic potentials, inhibitory post-synaptic potentials, and a complex mixture of excitatory and inhibitory potentials. These new discoveries provide details about synaptic transmission in rNST and thereby clarify the underlying mechanism by which gustatory information is processed.

[A study on P21(ras) in human lung cancer and body fluid of cancer patients]

The McAb of anti-P21(ras) has been used to screen 9 cases of human lung cancer tissues, 18 cases of samples and 2 cases of hydrothorax samples of lung cancer patients by means of PAGE-immunoblots. The expression of ras gene was found in 8 cases of human lung cancer among which the expression of 4 cases was higher than that of normal control. P21(ras) has not been detected in serum and hydrothorax samples of cancer patients. The present study indicated that there was P21(ras) in human lung cancer and normal control and the expression level of ras gene in lung cancer was related to the differentiation of cancer.