Swimming and ammonia toxicity in salmonids: the effect of sub lethal ammonia exposure on the swimming performance of coho salmon and the acute toxicity of ammonia in swimming and resting rainbow trout

This study tested the hypothesis that swimming exacerbates ammonia toxicity in fish. Both sub-lethal and acute toxicity testing was conducted in a swim tunnel on swimming and resting coho salmon and rainbow trout, respectively. The sub lethal tests on coho salmon also considered the compartmentalization of ammonia within the fish. Coho salmon showed a significant linear decrease in U(crit) both with increasing water ammonia (0, 0.02, 0.04 and 0.08 mg per l NH3) and increasing plasma ammonia. Data collected included plasma pH and ammonia, muscle pH and ammonia and muscle membrane potential. Based on results found in these experiments it was concluded that the reduction in swimming performance was due to both metabolic challenges as well as depolarization of white muscle. Acute toxicity testing on swimming and resting rainbow trout revealed that swimming at (60% U(crit) or approximately 2.2 body lengths/s) decreased the LC50 level from 207+/-21.99 mg N per l in resting fish to 32.38+/-10.81. The LC50 for resting fish was significantly higher than that for swimming fish. The acute value set forth by the US EPA at the same pH is 36.1 mg N per l and may not protect swimming fish. In addition the effect of water hardness on ammonia toxicity was considered. It was found that increased water calcium ameliorates ammonia toxicity in fish living in high pH water.

Thermoluminescence of MgSO4 doped with Eu and P impurities

CaSO4:Eu, MgSO4:Eu and MgSO4:Eu,P phosphors have been prepared and their thermoluminescence (TL) characteristics were studied. A main glow peak due to Eu2+ ions is seen at approximately 146 degrees C and 440 nm and glow peaks at approximately 145 degrees C, approximately 190 degrees C, approximately 260 degrees C and approximately 360 degrees C for 590 nm and 625 nm wavelengths are identified as Eu3+ ion emissions in MgSO4:Eu. Emission spectra in MgSO4:Eu and the MgSO4:Eu,P show that the MgSO4:Eu3+ glow peak at 260 degrees C for 590 nm and 625 nm shifts to 280 degrees C with enhanced intensity while the Eu2+ ion glow peak at 146 degrees C remains but with reduced intensity. The main glow peak at approximately 146 degrees C and 440 nm from Eu2+ ions shows significant difference from the characteristic glow peaks of Eu3+ ions. It is observed that the wavelength of the Eu2+ ion glow peak is inversely proportional to the radius of the cation of the host sulphate in alkaline-earth sulphate phosphors. By contrast the wavelengths of the Eu3+ ion glow peaks remain unchanged in different sulphates. Besides, the glow curve at approximately 146 degrees C obtained using a conventional blue sensitive reader shows simply the first order kinetics. It is concluded that the luminescence centres and distribution of traps related to Eu2+ ions are different from that of Eu3+ ions in MgSO4:Eu and MgSO4:Eu,P phosphors.

Morphologically Controlled Proton-Conducting Membranes Using Graft Polymers Possessing Block Copolymer Graft Chains

Ionic graft membranes comprising macromonomeric poly(styrene-block-styrene sulfonic acid) grafted polystyrene [PS-g-mac(PS-b-PSSA)] polymers were prepared by copolymerization of styrene and poly(styrene-block-sodium styrene sulfonate) (PS-b-PSSNa) macromonomers followed by ion-exchange. The latter were prepared with controlled molecular weight by stable free radical polymerization. Membranes exhibit varying degrees of phase separation. Membranes of low ion content are comprised of isolated ionic domains and exhibit low ionic conductivity. Increasing the number density of ionic graft chains in the polymer results in a network of nanochannels and a dramatic increase in ion conductivity. In comparison to analogous macromonomeric poly(styrene sulfonic acid) grafted polystyrene (PS-g-macPSSA) membranes, of similar ion exchange capacity (IEC) and PSSA chain length, dehydrated PS-g-mac(PS-b-PSSA) membranes consist of smaller, more densely connected ionic domains; however, water sorption and ionic conductivity are similar.

ERM-dependent movement of CD43 defines a novel protein complex distal to the immunological synapse

The large mucin CD43 is actively excluded from T cell/APC interaction sites, concentrating in a membrane domain distal to the site of TCR engagement. The cytoplasmic region of CD43 was necessary and sufficient for this antipodal movement. ERM cytoskeletal adaptor proteins colocalized with CD43 in this domain. An ERM dominant-negative mutant blocked the distal accumulation of CD43 and another known ERM binding protein, Rho-GDI. Inhibition of ERM function decreased the production of IL-2 and IFNgamma, without affecting PKC(theta) focusing or CD69 upregulation. These results indicate that ERM proteins organize a complex distal to the T cell/APC interaction site and provide evidence that full T cell activation may involve removal of inhibitory proteins from the immunological synapse.

Antigen-specific blockade of T cells in vivo using dimeric MHC peptide

Ag-specific immune tolerance in clinical organ transplantation is currently an unrealized but critical goal of transplant biology. The specificity and avidity of multimerized MHC-peptide complexes suggests their potential ability to modulate T cell sensitization and effector functions. In this study, we examined the ability of MHC-peptide dimers to modulate T cell function both in vitro and in vivo. Soluble MHC dimers induced modulation of surface TCR expression and inhibited T cell cytolytic activity at nanomolar concentrations in vitro. Furthermore, engagement of TCR by soluble dimers resulted in phosphorylation of the TCR zeta-chain and recruitment and phosphorylation of zeta-associated protein-70 to the signaling complex, the latter of which increased upon dimer cross-linking. Significantly, Ag-specific inhibition of an alloreactive TCR-transgenic T cell population in vivo resulted in consequent outgrowth of an allogeneic tumor. The prolonged Ag-specific suppression of expansion and/or effector function of cognate T cells in vivo suggests that soluble MHC dimers may be a means of inducing sustained Ag-specific T cell unresponsiveness in vivo.

Role of cyclic AMP responsive element in the UVB induction of cyclooxygenase-2 transcription in human keratinocytes

It has been shown that UVB irradiation induces expression of COX-2 and up-regulation of COX-2 plays a functional role in UVB tumor promotion. In this study, we examined the cis-elements in the human COX-2 promoter that may be responsible for the UVB induction of COX-2. Analyses with the COX-2 promoter region revealed that the cyclic AMP responsive element near the TATA box was essential for both basal and UVB induced COX-2 expression. This was further supported by studies using a dominant negative mutant of CREB, which strongly inhibited the activity of COX-2 promoter. Electrophoretic mobility shift assays indicated that CREB and ATF-1 were the major proteins binding to the COX-2 CRE. CREB and ATF-1 were phosphorylated upon UVB treatment, and SB202190, a p38 MAPK inhibitor, decreased the phosphorylation of CREB/ATF-1 and suppressed COX-2 promoter activity. In contrast, treatment with forskolin, an activator of adenylyl cyclase, led to phosphorylation of CREB and ATF-1 and activation of COX-2 promoter. Finally, enhanced binding of phospho-CREB/ATF-1 to the COX-2 CRE was observed after UVB induction. Thus, one signaling pathway for UVB induction of human COX-2 involves activation of p38, subsequent phosphorylation of CREB/ATF-1, and activation of the COX-2 CRE through enhanced binding of phosphorylated CREB/ATF-1.

Vesicle trafficking and cell surface membrane patchiness

Membrane proteins and lipids often appear to be distributed in patches on the cell surface. These patches are often assumed to be membrane domains, arising from specific molecular associations. However, a computer simulation (Gheber and Edidin, 1999) shows that membrane patchiness may result from a combination of vesicle trafficking and dynamic barriers to lateral mobility. The simulation predicts that the steady-state patches of proteins and lipids seen on the cell surface will decay if vesicle trafficking is inhibited. To test this prediction, we compared the apparent sizes and intensities of patches of class I HLA molecules, integral membrane proteins, before and after inhibiting endocytic vesicle traffic from the cell surface, either by incubation in hypertonic medium or by expression of a dominant-negative mutant dynamin. As predicted by the simulation, the apparent sizes of HLA patches increased, whereas their intensities decreased after endocytosis and vesicle trafficking were inhibited.

[Assay of trace elements and heavy metals in different growth stages of Ganoderma lucidum]

The trace elements and heavy metals in the different growth stages of Ganoderma lucidum were analyzed by ICP-MS, AFS and AAS. The fermented mycelia, fruiting bodies and spore contained all kinds of detected trace elements and heavy metals, the contents of which were higher in spore. The content of Se was same in different growth stages. Ganoderma lucidum had the ability of bio-enrichment of Ge.

Role of p38 MAP kinases and ERK in mediating ultraviolet-B induced cyclooxygenase-2 gene expression in human keratinocytes

The roles of p38 MAP kinases and ERK in UVB induced cox-2 gene expression were studied in a human keratinocyte cell line, HaCaT. UVB significantly increased cox-2 gene expression at both protein and mRNA levels. As we reported previously, p38 and ERK were significantly activated after UVB irradiation in HaCaT cells. In addition, treating the cells with p38 inhibitor SB202190 or MEK inhibitor PD98059 specifically inhibited UVB induced p38 or ERK activation, respectively. In this study, we further examined the roles of p38 and ERK in UVB induced cox-2 gene expression in HaCaT cells. We found that SB202190 strongly inhibited UVB induced COX-2 protein expression at different time points and various UVB doses. Furthermore, SB202190 markedly inhibited UVB induced cox-2 mRNA. Our data indicated that ERK did not play a role in UVB induced cox-2 gene expression in human keratinocytes since suppression of ERK did not significantly alter UVB induced increase of COX-2 protein and mRNA. These results suggested, for the first time, that activation of p38 is required for UVB induced cox-2 gene expression in human keratinocytes. Since cox-2 expression plays an important role in UV carcinogenesis, p38 could be a potential molecular target for chemoprevention of skin cancer.

Roles of Akt and glycogen synthase kinase 3beta in the ultraviolet B induction of cyclooxygenase-2 transcription in human keratinocytes

Ultraviolet B (UVB)-induced cyclooxygenase-2 (COX-2) expression plays an important role in UVB tumor promotion. We examined whether Akt and glycogen synthase kinase 3beta (GSK-3beta), components of the phosphatidylinositol 3'-kinase pathway, are involved in UVB induction of COX-2 transcription. UVB caused Akt phosphorylation at both Thr-308 and Ser-473 that was inhibited by LY294002, a phosphatidylinositol 3'-kinase inhibitor. LY294002 also decreased the expression of endogenous COX-2 protein and a luciferase construct driven by COX-2 promoter. Similarly, UVB caused phosphorylation of GSK-3beta (Ser-9) and presumably inactivation of GSK-3beta. Inhibition of GSK-3beta by lithium induced endogenous COX-2 protein expression and COX-2 promoter activity. Finally, overexpression of a dominant-negative Akt mutant or wild-type GSK-3beta suppressed UVB-mediated induction of COX-2 promoter. These studies suggest that inactivation of GSK-3beta through activation of Akt plays an important role in the UVB induction of COX-2 transcription.

Elimination of active tad elements during the sexual phase of the Neurospora crassa life cycle

Tad is an active LINE-like retrotransposon isolated from the Adiopodoumé strain of Neurospora crassa. Extensive analysis of other Neurospora strains has revealed no other strain with active Tad, but all strains tested have multiple copies of defective Tad elements. We have examined the ability of Tad to survive during the sexual cycle of Neurospora and find that active Tad is rapidly eliminated. The characteristics of this elimination suggest that the repeat-induced point mutation (RIP) mechanism was responsible. By the use of transformation to switch the mating type of the Adiopodoumé strain we concluded that this strain is not defective in the RIP process. Analysis of defective Tad elements isolated from a variety of strains indicates that the major difference between these elements and active Tad is due to the presence of a large number of G-C to A-T transition mutations. This would be expected if the changes were due primarily to the RIP process. Mapping of a selection of defective Tad elements reveals that they are present on all of the chromosomes; however, many of the elements are not widely shared among strains. This suggests that repeated introduction and elimination of Tad elements has occurred. Mechanisms that might be responsible for this repeated introduction are discussed.

[Studies on calluses induced from various explants of Cistanche deserticola]

Calluses were induced from various explants (flower, stem, bud and squama) of Cistanche deserticola Y.C.Ma and compared with each other. The result showed that the inducement rate of ovary and stem were higher than that of other explants which the inducement time was short and the characters of calluses were good. The effect of basal culture medium added hormone on callus reproduction was also studied. The result showed that B5 culture medium added 1 mg/L IBA and 2 mg/L 6-BA was optimal.

[Maintenance ration and conversion efficiency of Hyporhamphus sajori]

The maintenance ration and conversion efficiency of Japanese halfbeak, Hyporhamphus sajori were tested with enclosures installed in a shrimp raising pond. The results showed that there existed an evident relationship between daily ration(DR) and growth rate(GR) of the fish, GR = 140.37 DR - 24.03. The conversion efficiency was 13.96% in biomass or 16.12% in energy. The maintenance ration was 17.12% and 20.39% of body weight in terms of growth rate and specific growth rate, respectively, indicating that it could be deduced from growth rate quite differently from that from specific growth rate in the same experiment. The abnormal growth rate appeared when daily ration was below 3.30% of body weight, implied that Japanese halfbeak may get other food resources besides supplied net zooplankton.

Development and applications of surface-linked single chain antibodies against T-cell antigens

In this report the use of surface-linkage to expand the potential experimental and therapeutic applications of single chain antibody (scFv) constructs is reviewed. A strategy for the generation and functional characterization of surface-linked scFvs that bind selectively to the T-cell proteins CD3epsilon, CD28, and CD152 (CTLA-4) is described in detail. Experimental examples are provided of the use of these constructs to study the positive and negative regulation of T-cell activation and to manipulate the in vivo immunogenicity of tumor cells. In addition, a novel system for Simultaneous T-cell Activation and Retroviral Transduction (START) is described in which retroviral packaging cells are rendered mitogenic for T lymphocytes by combined expression of surface-linked scFvs. Finally, the use of random mutagenesis and yeast surface display to increase the affinity and functional efficacy of scFv constructs is demonstrated.

[Analysis on the present situation of human rabies epidemic in China]

OBJECTIVE

To summarize and analyze human rabies epidemic situation in the last five years in China and to explore the possible factors causing the rising of epidemics to provide reference for the prevention and control of rabies in the future.

METHODS

Collecting and analyzing data of rabies epidemics in the last five years in whole nation.

RESULTS

Human rabies is continuing going up in the last five years in China with an increase of 44.65%, 1.74% and 45.93% in 1997, 1998, 1999. Human rabies incidence was also seen an increase from 0.0134/100,000 in 1996 to 0.02708/100,000 in 1999. The provinces of rabies increase were mainly located in south China. Among them, Jiangsu province reported 40 human cases in 1999, which increased 207.69% than the corresponding period in 1998. The cases in these high epidemic provinces took up 75% of the whole nation's cases. Number of reported rabies case was also rising.

CONCLUSION

Facts as increasing number of dog raising, having not been injected with rabies vaccine and antirabies serum timely or full course after exposure, unstrictly controlling the quality of rabies vaccine as well as lacking good cooperation in different official department on rabies control might serve as factors responsible for the recurrent increase of human rabies.

[The sensitivity to apoptosis is enhanced in U937-ASPI-3K cells which stably express antisense ATM/PI-3K]

OBJECTIVE

To analyse the characteristics of apoptosis sensitivity in U937-ASPI-3K cells which is stably expressing anti-sense ATM/PI-3K.

METHOD

Annexin V-PI apoptosis detection kid and flow cytometry were used to determine apoptosis rate, Western blot to the expression level of cytochrome C protein and Bcl-2 protein.

RESULTS

U937-ASPI-3K cells had a lowered threshold for triggering apoptosis in response to low dose irradiation. Cell apoptosis rate was 28% and (53.0 +/- 5.4)%, respectively, at 8 and 48 hours after 1.5 Gy (137)Cs irradiation, while in U937-pZEOSV2 (+) control group it was 4.2% and (11.0 +/- 3.3)%, respectively. Cytosolic cytochrome C protein band was gradually intensified in U937-ASPI-3K in 4 - 8 h after irradiation, but was not detected in control group. Bcl-2 protein gradually decreased in U937-ASPI-3K in 4 - 8 h after irradiation, but didn't change obviously in control group.

CONCLUSION

Cell line U937-ASPI-3K acquired a phenotype with a lowered threshold for triggering apoptosis. It demonstrated that selective inactivation of ATM gene might be of considerable value in tumor treatment.

[Environmental characteristic of walleye pollock fishing ground in high seas of the Okhotsk Sea in summer]

Based on the acoustic survey on the resource of walleye pollock (Theragra chalcogramma) in the high seas of the Okhotsk Sea, the distribution of walleye pollock and the environmental characteristics of its fishing ground were studied, and the relationship between them were analyzed. In August, the high schooling area of walleye pollock was situated in the waters with a depth of less than 500 meters and to the north of 55 degrees N. Walleye pollock mainly distributed in 150-300 m depth, and lived in groups. The main food was Euphausia pacifica, and the densely populated area of wall-eye pollock was roughly consistent with that of Euphausia pacifica. The thermocline was observed at 0-50 m depth, the temperature changed at a rate of 0.25 degree C per meter, and the cold water mass was roughly located in 50-150 m layer. The fish was mainly distributed in the layer below the cold water mass, because of the impeding effect of thermocline and the limiting action of fish food. It seldom inhabited the water below 400 m depth, partly because the dissolved oxygen there was rather low.

[Clinical study on morphological characteristics of placenta in severe pregnancy induced hypertension]

OBJECTIVE

To study morphological characteristics of placenta in severe pregnancy induced hypertension (SPIH) and its relationship to pregnant outcome.

METHODS

Morphological changes were observed by light microscopy; Blood biochemical analyses were used to predispose pregnant outcome.

RESULTS

Difference in pathological changes of placental bed between normal term pregnancy (NTP) and SPIH groups was significant: the placental weight, proliferation of cytotrophoblasts, numbers of the placental villi with syncytial knots, thickness of basal lamina, fibrinoid necrosis and deposition of matrix, stromal edema and fibrosis of villi, the vascular numbers of villi, stasis; lack of physiologic changes in decidual spiral arteries. Clinical examination showed that the rate of anemia, thrombocytopenia, blood concentration, hypoproteinemia, ascites, eye ground artery spasm in SPIH were higher in NIT.

CONCLUSIONS

Pathological changes of placenta play important roles in development of SPIH, and the pathological changes are paralleled with the severity of the disease.

Replication but not transcription of simian virus 40 DNA is dependent on nuclear domain 10

DNA viruses from several families including herpes simplex virus type 1, adenovirus type 5, and simian virus 40 (SV40), start their transcription and replication adjacent to a specific nuclear domain, ND10. We asked whether a specific viral DNA sequence determines the location of these synthetic activities at such restricted nuclear sites. Partial and overlapping SV40 sequences were introduced into a beta-galactosidase expression vector, and the beta-galactosidase transcripts were localized by in situ hybridization. Transcripts derived from control plasmids were found throughout the nucleus and at highly concentrated sites but not at ND10. SV40 genomic segments supported ND10-associated transcription only when the origin and the coding sequence for the large T antigen were present. When the large T-antigen coding sequence was eliminated but the T antigen was constitutively expressed in COS-7 cells, the viral origin was sufficient to localize transcription and replication to ND10. Deletion analysis showed that only the large T-antigen binding site II (the core origin) was required but the T antigen was needed for detectable transcription at ND10. Large T antigen expressed from plasmids without the viral core origin did not bind or localize to ND10. Blocking of DNA replication prevented the accumulation of transcripts at ND10, indicating that only sites with replicating templates accumulated transcripts. Transcription at ND10 did not enhance total protein synthesis of plasmid transcripts. These findings suggest that viral transcription at ND10 may only be a consequence of viral genomes directed to ND10 for replication. Although plasmid transcription can take place anywhere in the nucleus, T-antigen-directed replication is apparently restricted to ND10.

[An evaluation of adenosine triphosphate bioluminescence assay for tumor in vitro chemosensitivity testing]

This study was aimed at the feasibility of using ATP-bioluminescence assay for tumor in vitro chemosensitivity testing. With the use of this assay, the authors determined dose-response curve in mouse fibroma cell line L929 treated with chemotherapeutic agents, and investigated the different in vitro responses of 6 ovarian carcinomas (5 from fresh tumor tissues, 1 from ascites) treated with etopside, cis-plating, 5-fluorouracil and adriamycin. The results showed that the coefficients of variation for triplicate assays ranged from 1.2% to 15.8% which means high reproducibility of the assay. The single cell suspension (including < 30 cells clusters) could be separated from tissue fragments by means of enzyme cocktail (collagenase, Dnase, pronase). The viable cells were over 90%. This study demonstrates that ATP-bioluminescence assay is a sensitive, reliable and efficient method for tumor chemosensitivity testing. In this connection, the correlation between in vitro drug sensitivity and in vivo patient response is worth further studying.

Capillary electrochromatography using continuous-bed columns of sol-gel bonded silica particles with mixed-mode octadecyl and propylsulfonic acid functional groups

Continuous-bed columns containing sol-gel bonded 3 microm silica particles with mixed-mode octadecyl and propylsulfonic acid functional groups (ODS/SCX) were prepared by first packing the ODS/SCX particles into a fused-silica capillary, then filling the packed capillary with a siliceous sol-gel, curing the sol-gel, and finally drying the column with supercritical carbon dioxide. The performance of the sol-gel bonded ODS/SCX columns was evaluated for capillary electrochromatography using acetonitrile aqueous mobile phase containing phosphate buffer. The columns were mechanically strong and permeable. Both EOF velocity and current increased linearly with elevation of the applied electric field strength. The EOF velocity was high at low pH and nearly constant over a range of pH 2-9. Higher buffer concentration resulted in higher current and lower EOF velocity. The acetonitrile content had no significant effect on the EOF. Without thermosetting the column, no bubble formation was noticed with currents up to 2.5 microA. The minimum plate height of a 25/34 cm x 75 microm I.D. sol-gel bonded 3 microm ODS/SCX column was 5.7 microm (1.75 x 10(5) plates per meter) at an optimum EOF velocity of 0.92 mm s(-1). Mixtures of test aromatic compounds and aromatic hydrocarbon homologues gave symmetrical peaks when using a low pH mobile phase. The retention and elution order of aromatic compounds represented a typical reversed-phase separation mechanism similar to conventional ODS columns. The run-to-run and column-to-column retention factor reproducibility was better than 2.5% and 8.0% RSD, respectively.

[Assimilation efficiency of pacific oyster Crassortrea gigas]

The effects of body size, food density and its quality on assimilation efficiency of pacific oyster (Crassostrea gigas) were studied under artificial conditions in laboratory. The experimental results show that the filtration and ingestion rates of pacific oyster increased with its body size, which tallied with power function. The assimilation efficiency of pacific oyster was not significantly correlated with its body size, but correlated positively with the organic matter content of food and negatively with food density.

A preliminary approach on mass-balance ecopath model of the Bohai Sea

A Bohai Sea mass-balance ecopath model is constructed on the basis of fisheries resources data from the ecosystem survey conducted from April 1982 to May 1983. It is the first ecopath model which consists of 13 function groups (boxes), and only covers the main trophic flow in the Bohai Sea ecosystem. P/B and Q/B parameters (P: production, B: biomass, Q: consumption) for most groups were estimated from similar function groups in other ecopath models of the same latitude regions around. The value of EE (Ecotrophic Efficiency) is the main parameter to check the equilibration of the model. The EE parameters in the model are of high value (> 0.808) for most groups, because the fishing pressure was very high and small living organisms were being heavily preyed upon in the ecosystem. The biomass density of the species commercially utilized estimated by the model is 12.33 ton.km-2. Even though the value is low compared with the density in other ecosystems, such as Caribbean coral reef ecosystem and the Southern B.C. shelf model, it is higher than the value published by some papers on the Bohai Sea using other methods. Considering the lower value estimated by the stock assessment using bottom trawl survey data, the output here is reasonable. It is concluded that the biomass of commercial fishing species in the sea is 950 thousand metric tons, and 338 thousand tons are fish species in the value.

[Effects of YMB injection on hemorheology in rats]

This study was designed to elucidate the mechanism of YMB Injection on anti-CAD therapy. Fufang Danshen Injection was used as positive control and saline was taken as negative control to study the effects of traditional medicine YMB Injection on hemorheological parameters in normal rats and hypostasis rats. The results showed YMB Injection had no effect on hemorheological parameters of normal rats, but it could effectively decrease whole blood viscosity and whole blood reduction viscosity of hypostasis rats. The data implied that YMB Injection could decrease blood viscosity and hence improve blood supply of the graft in anti-CAD therapy.

[An adenosine triphosphate bioluminescence assay for detecting the number of living cells]

The method for detecting the number of living cells was studied. Using an adenosine triphosphate (ATP) bioluminescence assay, the present authors reported a perfect linear relationship between lg ATP concentrations and lg luminescence counts (r = 0.9963) as well as a relationship between lg number of cells and lg ATP luminescence counts (r = 0.9922). The detectable cells ranged from 10(2) to 10(6) cells/ml, the coefficients of variation 1-3%. This method is simple, accurate and sensitive and has a high reproducibility.

Dynorphin A elicits an increase in intracellular calcium in cultured neurons via a non-opioid, non-NMDA mechanism

The opioid peptide dynorphin A is known to elicit a number of pathological effects that may result from neuronal excitotoxicity. An up-regulation of this peptide has also been causally related to the dysesthesia associated with inflammation and nerve injury. These effects of dynorphin A are not mediated through opioid receptor activation but can be effectively blocked by pretreatment with N-methyl-D-aspartate (NMDA) receptor antagonists, thus implicating the excitatory amino acid system as a mediator of the actions of dynorphin A and/or its fragments. A direct interaction between dynorphin A and the NMDA receptors has been well established; however the physiological relevance of this interaction remains equivocal. This study examined whether dynorphin A elicits a neuronal excitatory effect that may underlie its activation of the NMDA receptors. Calcium imaging of individual cultured cortical neurons showed that the nonopioid peptide dynorphin A(2-17) induced a time- and dose-dependent increase in intracellular calcium. This excitatory effect of dynorphin A(2-17) was insensitive to (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10-imine (MK-801) pretreatment in NMDA-responsive cells. Thus dynorphin A stimulates neuronal cells via a nonopioid, non-NMDA mechanism. This excitatory action of dynorphin A could modulate NMDA receptor activity in vivo by enhancing excitatory neurotransmitter release or by potentiating NMDA receptor function in a calcium-dependent manner. Further characterization of this novel site of action of dynorphin A may provide new insight into the underlying mechanisms of dynorphin excitotoxicity and its pathological role in neuropathy.

[Gastric evacuation rate of black sea bream(Sparus macrocephalus)]

The gastric evacuation rate of black sea bream(Sparus macrocephalus) weighing 20-40 g was determined at 18 degrees C in laboratory. Three mathematical models were applied to simulate it. The result indicated that all of these three kinds of models fitted to the experiment data, while statistical analysis showed that the linear model was the best, whether the remained food in stomach was expressed by wet weight or dry weight. When the remained food in stomach was expressed by wet weight, the model was Y = 1.14 - 0.06 t(r2 = 0.82, p < 0.001), and by dry weight, it was Y = 1.36 - 0.07 t(r2 = 0.62, p < 0.001). The gastric evacuation rate of black sea bream was 6-7% of consumed food per hour at 18 degrees C.

Composite cavity semiconductor fiber ring laser

A passive subring cavity that served as mode selector was inserted into a semiconductor fiber ring laser to generate a stable lasing spectrum. A narrow linewidth of less than 10 kHz with unidirectional operation in the composite cavity ring laser was achieved. Tuning over a range of 20 nm was obtained by application of 0-30 V dc to a piezoelectric transducer in the subring cavity.

[Studies on schedules for human rabies immunization]

OBJECTIVES

To study the feasibility of interferon (INF) plus an immunization schedule of two dose-two dose-one dose (2 - 2 - 1) of rabies vaccine and a simple 2 - 2 - 1 schedule, and to explore immune regulation mechanism of INF.

METHODS

For an IFN plus 2 - 2 - 1 schedule, 5.0, 5.0 and 2.5 I.U. of primary hamster kidney cell rabies vaccine (PHKCV) were injected on the 1st, 7th and 14th day, respectively, and 0.2 million I.U. of IFN-alpha on the 1st day simultaneously. For a simple 2 - 2 - 1 schedule, only 5.0, 5.0 and 2.5 I.U. PHKCV were injected on the 1st, 7th and 14th day, respectively. And, for controls, a routine schedule recommended by WHO was used.

RESULTS

On the 7th day after immunization, their geometric mean titer (GMT) of antibody was 1.71, 1.57 and 1.21 for the above three schedule groups, respectively; on the 14th day, 62.77, 58.79 and 28.96; on the 45th day, 76.64, 72.90 and 62.22. Conversion rate of antibody was 85.00%, 61.11% and 65.00%, respectively on the 7th day, and was 100.00% for all on the 14th day. Proportion of those with protective antibody level was 10.00%, 0.00% and 0.00%, respectively for the three schedule groups, on the 7th day; 100.00%, 100.00% and 95.00%, on the 14th day; and was 100.00% for all on the 45th day. Proportion of those with antibody titer more than 1:1 was 55.00%, 33.33% and 20.00%, respectively, on the 7th day. Adverse reaction rate was 0.00% - 55.00%, without significant difference between three schedule groups.

CONCLUSIONS

Lower dose of IFN could enhance the effect of immune response to rabies vaccine. IFN plus 2 - 2 - 1 rabies vaccine schedule was better than that of simple 2 - 2 - 1 schedule, while the later was better than the routine schedule.

[An electron microscopic histochemical study on the fibrous formation in pleomorphic adenoma of the salivary gland]

OBJECTIVE

To study the kinds of fibers and mechanism of fibrous formation in myxochondroid tissue of pleomorphic adenoma.

METHODS

Eight cases of pleomorphic adenomas of salivary gland were studied by histological and electron microscopic histochemical techniques.

RESULTS

The histological study showed that collagenous fibers and elastic fibers which constituted the trestle were distributed in myxochondroid areas of pleomorphic adenoma. The electron microscopic histochemical study showed that the myxochondroid tissue contained slender collagen fibrils measuring 50 nm in diameter and heavily stained elastic fibers. In cytoplasm of the myxochondroid cells two types of the Golgi-derived vesicles were seen: one was small round vesicles with a uniform electron dense core of amorphous material and heavily stained; another type was small round vesicles with a non-uniform electron dense core of filamentous material and stained grey. These materials were released into the extracellular space by cytoplasmic exocytosis.

CONCLUSIONS

Neoplastic myoepithelial cells have the ability to synthesize and secrete procollagen and precursor of elastin, thus forming collagenous fibers and elastic fibers in myxochondroid areas.

[Effect of gandou decoction on copper metabolism of skin fibroblast of hepatolenticular degeneration model]

OBJECTIVE

To explore the cytological mechanism of Gandou Decoction (GDD) in treating hepatolenticular degeneration (HLD).

METHODS

Twenty-three in vitro models of cultured skin fibroblast of HLD were established to observe the intracellular change of microelements (Cu2+, Zn2+, etc.) content before and after adding rabbit's serum containing GDD.

RESULTS

After being treated with GDD contained serum for 24 hours, the intracellular content of Cu2+ decreased from (80.94 +/- 34.76) ng/mg to (46.90 +/- 22.14) ng/mg, P < 0.01, while that of Zn2+ increased from (140.43 +/- 33.81) ng/mg to (151.43 +/- 37.83) ng/mg, P < 0.01.

CONCLUSION

GDD is quite effective in removing the intracellular copper and increasing the intracellular zinc.

High-affinity interaction of (des-Tyrosyl)dynorphin A(2-17) with NMDA receptors

The opioid peptide dynorphin A elicits non-opioid receptor-mediated, neurotoxic response in vivo, which is blocked by pretreatment with MK-801, a noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist. In the present study, we examined the possible direct interaction of dynorphin A on the NMDAR. A nonopioid dynorphin A analog, (125)I-(des-tyrosyl) dynorphin A(2-17), was used in radioligand binding analysis on rat cortical brain membranes. This radioligand exhibited a saturable, specific binding at high affinity with a K(d) value of 9.4+/-1.6 nM and maximal binding of 2.4+/-0.6 pmol/mg protein. This binding site was associated with the NMDAR complex because it was modulated by a number of NMDAR ligands. Transient expression of the rat NR1a/NR2A complex in human embryonic kidney 293 cells confirmed a coexpression of (125)I-(des-tyrosyl) dynorphin A(2-17), [(3)H]CGP39,653, and [(3)H]MK-801 binding. These data provide direct evidence of the presence of a high-affinity binding site for dynorphin A on the NMDAR. The modulatory effect of the various NMDAR-selective ligands on dynorphin A binding suggests that dynorphin A may bind preferentially to the closed/desensitized state of the NMDAR. The physiological role of dynorphin A binding to the NMDAR remains to be established.

[Relationship between methylation status of gamma-glutamyl transpeptidase (GGT) genes and abnormal expression of its enzyme proteins in tissues of human hepatomas]

OBJECTIVE

To explore the mechanism of expression and alteration of gamma-glutamyl transpeptidase (GGT) genes during the development of human hepatomas.

METHODS

The total GGT protein and total RNA were purified in human hepatomas, adjacent paracancerous and distal cancerous tissues. The specific activities of total GGT, membrane-combine GGT and soluble GGT were investigated, the GGT gene of 5'-NC region was amplified by using a nest RT-PCR assay, and methylation status of GGT gene M3 site were analyzed in the present study.

RESULTS

An increasing tendency (P < 0.05) of total RNA concentrations was found from cancer in distal cancerous tissues; the specific activities (U/g) of total GGT, membrane-combine GGT and soluble GGT were significantly higher (P < 0.05) in hepatomas than those in adjacent paracancerous or and that distal cancerous tissues; and the frequencies of amplified fragment and hypomethylated M3 site of GGT 5'-NC region genes were 100% and 75% in hepatomas, 85% and 55% in adjacent cancerous, and 75% and 50% in distal cancerous tissues, respectively.

CONCLUSIONS

The present data suggest that the abnormal expression of GGT proteins in hepatomas was related to hypomethylation status of GGT genes, and that the fragment analysis of the GGT genes might be a sensitive assay to monitor the hepatic cell canceration.

A new mechanism of neurodegeneration: a proinflammatory cytokine inhibits receptor signaling by a survival peptide

Heightened expression of both a proinflammatory cytokine, tumor necrosis factor alpha (TNF-alpha), and a survival peptide, insulin-like growth factor I (IGF-I), occurs in diverse diseases of the central nervous system, including Alzheimer's disease, multiple sclerosis, the AIDS-dementia complex, and cerebral ischemia. Conventional roles for these two proteins are neuroprotection by IGF-I and neurotoxicity by TNF-alpha. Although the mechanisms of action for IGF-I and TNF-alpha in the central nervous system originally were established as disparate and unrelated, we hypothesized that the signaling pathways of these two cytokines may interact during neurodegeneration. Here we show that concentrations of TNF-alpha as low as 10 pg/ml markedly reduce the capacity of IGF-I to promote survival of primary murine cerebellar granule neurons. TNF-alpha suppresses IGF-I-induced tyrosine phosphorylation of insulin receptor substrate 2 (IRS-2) and inhibits IRS-2-precipitable phosphatidylinositol 3'-kinase activity. These experiments indicate that TNF-alpha promotes IGF-I receptor resistance in neurons and inhibits the ability of the IGF-I receptor to tyrosine-phosphorylate the IRS-2 docking molecule and to subsequently activate the critical downstream enzyme phosphatidylinositol 3'-kinase. This intracellular crosstalk between discrete cytokine receptors reveals a novel pathway that leads to neuronal degeneration whereby a proinflammatory cytokine inhibits receptor signaling by a survival peptide.

[Component in diphtheria-pertussis-tetanus-hepatitis B vaccine]

OBJECTIVE

To study immunogenecity of yeast-derived recombinant hepatitis B (YHB) component in diphtheria-pertussis-tetanus-YHB vaccine (DPTw-YHB).

METHODS

Immunogenecity of tetra-valent DTPw-YHB vaccine and mono-valent recombinant YHB vaccine, and that of the tetra-valent vaccine with varied YHB component were compared. The efficiency and stability of recombinant YHB in the tetra-valent vaccine stored at 2 - 8 degrees C for 18 months were determined.

RESULTS

The efficiency of recombinant YHB in the tetra-valent vaccine enhanced significantly in mice, as compared with that of mono-valent recombinant YHB vaccine, with an average mouse ED(50) of 1:2.0 - 1:3.1. There was no significant difference in efficiency of the tetra-valent vaccine with varied recombinant YHB component. Recombinant YHBin the DPTw-YHB tetra-valent vaccine still kept good stability stored at 2 - 8 degrees C for 18 months.

CONCLUSION

Recombinant YHB in the tetra-valent vaccine was more immunogenic than the mono-valent YHB vaccine. No interference and inhibition of DPTw to recombinant YHB was found, indicating good compatibility between DPTw and YHB.

[Determination of triptolide in tripterygium preparations by gradient high performance liquid chromatography]

A gradient elution method was developed for the separation and determination of triptolide in Tripterygium wilfordii Hook preparations by high performance liquid chromatography (HPLC) using YWG column made in China. Methanol with 0.05 mol/L KH2PO4 was used as mobile phase, and the photodiode array detector was used at lambda = 218 nm. The sample of tripterygium oral preparation was extracted with ethanol and then by chloroform. The extract solution was evaporated and the residue was dissolved in 10 mL of ethanol as a sample solution. The spectrum was obtained by the subtraction of spectrum of ethanol from that of sample solution. In comparing with isocratic elution, the gradient operation used in this paper had higher resolution and sensitivity. The calibration curve was linear over the range of 1.32-21.10 mg/L (r = 0.9999). The average recovery of the method was 97.59%. The method was applied to separate and determine the triptolide in tripterygium tablets and the results indicated that the triptolide content by this method was less than that by isocratic and label-claimed one.

Disrupted retinal development in the embryonic belly spot and tail mutant mouse

The Belly spot and tail (Bst) semidominant mutation, mapped to mouse Chromosome 16, leads to developmental defects of the eye, skeleton, and coat pigmentation. In the eye, the mutant phenotype is characterized by the presence of retinal colobomas, a paucity of retinal ganglion cells, and axon misrouting. The severity of defects in the Bst/+ retina is variable among individuals and is often asymmetric. In order to determine the role of the Bst locus during retinal morphogenesis, we searched for the earliest observable defects in the developing eye. We examined the retinas of Bst/+ and +/+ littermates from embryonic day 9.5 (E9.5) through E13.5 and measured retinal size, cell density, cell death, mitotic index, and cell birth index. We have found that development of the Bst/+ retina is notably dilatory by as early as E10.5. The affected retinas are smaller than their wildtype counterparts, and optic fissure fusion is delayed. In the mutant, there is a marked lag in the exit of retinal cells from the mitotic cycle, even though there are no observable differences in the rate of cellular proliferation or cell death between the two groups. We hypothesize that Bst regulates retinal cell differentiation and that variability of structural defects in the mutant, such as those affecting optic fissure fusion, is a reflection of the extent of developmental delay brought about by the Bst mutation.

The immune-endocrine loop during aging: role of growth hormone and insulin-like growth factor-I

Why a primary lymphoid organ such as the thymus involutes during aging remains a fundamental question in immunology. Aging is associated with a decrease in plasma growth hormone (somatotropin) and IGF-I, and this somatopause of aging suggests a connection between the neuroendocrine and immune systems. Several investigators have demonstrated that treatment with either growth hormone or IGF-I restores architecture of the involuted thymus gland by reversing the loss of immature cortical thymocytes and preventing the decline in thymulin synthesis that occurs in old or GH-deficient animals and humans. The proliferation, differentiation and functions of other components of the immune system, including T and B cells, macrophages and neutrophils, also demonstrate age-associated decrements that can be restored by IGF-I. Knowledge of the mechanism by which cytokines and hormones influence hematopoietic cells is critical to improving the health of aged individuals. Our laboratory has recently demonstrated that IGF-I prevents apoptosis in promyeloid cells, which subsequently permits these cells to differentiate into neutrophils. We also demonstrated that IL-4 acts much like IGF-I to promote survival of promyeloid cells and to activate the enzyme phosphatidylinositol 3'-kinase (PI 3-kinase). However, the receptors for IGF-I and IL-4 are completely different, with the intracellular beta chains of the IGF receptor possessing intrinsic tyrosine kinase activity and the alpha and gammac subunit of the heterodimeric IL-4 receptor utilizing the Janus kinase family of nonreceptor protein kinases to tyrosine phosphorylate downstream targets. Both receptors share many of the components of the PI 3-kinase signal transduction pathway, converging at the level of insulin receptor substrate-1 or insulin receptor subtrate-2 (formally known as 4PS, or IL-4 Phosphorylated Substrate). Our investigations with IGF-I and IL-4 suggest that PI 3-kinase inhibits apoptosis by maintaining high levels of the anti-apoptotic protein Bcl-2. The sharing of common activation molecules, despite vastly different protein structures of their receptors, forms a molecular explanation for the possibility of cross talk between IL-4 and IGF-I in regulating many of the events associated with hematopoietic differentiation, proliferation and survival.

[Immunologic and clinical study of paraneoplastic limbic encephalitis]

OBJECTIVE

To probe into the pathogenic mechanisms of paraneoplastic limbic encephalitis (PLE) in patients with small cell lung carcinoma (SCLC).

METHODS

The indirect immunoperoxidase method and Western blot analysis were used for detecting anti-Hu antibodies in 16 PLE patients associated with SCLC. Autopsy and pathological study were performed on two cases.

RESULTS

Eight patients (50%) had anti-Hu antibodies (anti-Hu+) whereas eight patients (50%) no detectable antineuronal antibodies (anti-Hu-). The clinical and laboratory features of PLE and time to diagnosis of SCLC were similar in the anti-Hu+ and anti-Hu- groups. Involvement of other areas of the nervous system in seven (87.5%) patients of the anti-Hu+ group but in only one (12.5)% of the anti-Hu- group (P = 0.012).

CONCLUSIONS

The presence of this characteristic neurological disorder strongly suggested that with an accompanying SCLC, existence of anti-Hu autoantibody was in favour of an autoimmune mechanism participating in PLE.

[Determination of chemical constituents of the volatile oil from Curcuma longa by gas chromatography-mass spectrometry]

The study of chemical constituents of the volatile oil from Curcuma longa is reported. The volatile oil was extracted by steam distillation. Fifteen components in the oil were separated and identified by gas chromatography-mass spectrometry(GC/MS). The results were elucidated based on the NBS standard mass spectral data. The total ion current chromatogram showed their mass fraction by normalization method. alpha-curcumene, alpha-zingiberene, 1,8-cineole and zerumbone, which had been reported before were found in Curcuma longa volatile oil, but 1-(3-cyclopentylpropyl)-2,4-dimethylbenzene, beta-sesquiphellandrene, germacrene etc identified simultaneously in the oil had never been reported. The major chemical constituent of the volatile oil from Curcuma longa is alpha-curcumene.

Prevention by inhibitors of arachidonic acid cascade of liver carcinogenesis, cirrhosis and oxidative DNA damage caused by a choline-deficient, L-amino acid-defined diet in rats

Effects of inhibitors of arachidonic acid (AA) cascade on the development of fatty liver, cirrhosis, glutathione S-transferase placental form (GST-P)-positive preneoplastic nodules, neoplastic nodules and generation of 8-hydroxydeoxyguanosine (8-OHdG), caused by a choline-deficient, L-amino acid-defined (CDAA) diet, were examined in Fischer 344 male rats by feeding CDAA diet supplemented with the inhibitors for 12 and 30 weeks. None of the inhibitors affected fatty liver. Among cyclooxygenase (COX) inhibitors, an irreversibly acting acetylsalicylic acid and a long-acting piroxicam, and to a much lesser extent the short-acting ibuprofen but not indomethacin, inhibited the development of cirrhosis, GST-P-positive and neoplastic nodules and generation of 8-OHdG. A phospholipase A2 inhibitor p-bromophenacylbromide (BPB) also exerted similar but lesser extent of inhibitory effects. Lipoxygenase inhibitors quercetin and nordihydroguiaretic acid inhibited GST-P-positive nodules but not cirrhosis or 8-OHdG. Present results suggest that perturbed AA cascade, particularly augmented COX pathway, might play key roles in the causation of liver lesions in the CDAA diet model.

Partial TCR signals delivered by FcR-nonbinding anti-CD3 monoclonal antibodies differentially regulate individual Th subsets

Anti-CD3 mAbs with low FcR affinity prolong graft survival in the absence of the cytokine-mediated toxicity observed with conventional anti-CD3 treatment. Previous studies have shown that FcR-nonbinding anti-CD3 mAbs suppress immune responses, at least in part, by delivering a partial signal resulting in Th1 unresponsiveness. In this study, the biochemical and functional consequences of FcR-nonbinding anti-CD3 treatment for various activated T cell populations were examined. In contrast to Th1 cells, FcR-nonbinding anti-CD3-treated Th2 cells secreted IL-4 and proliferated. Furthermore, Th2 cells cultured with the mAb were not rendered unresponsive. Mixed "Th0" populations responded to FcR-nonbinding anti-CD3 by producing IL-4, and showed a selective decrease in IL-2 production following preculture with the mAb. The stimulation of IL-4-producing cells did not reflect a more complete TCR signal, since similar defects in zeta, ZAP-70, and MAP kinase phosphorylation were observed in Th1 and Th2 cells. Despite the proximal signaling defects, FcR-nonbinding anti-CD3 induced nuclear translocation of NF-ATc. Thus, Abs that deliver partial TCR signals may promote development of a Th2 phenotype during the course of an immune response via selective effects on different Th subsets.

Disruption of the heme iron-proximal histidine bond requires unfolding of deoxymyoglobin

The unfolding behavior of 10 different distal heme pocket mutants of sperm whale deoxymyoglobin (deoxyMb) has been investigated. The effects of distal histidine (His 64) replacement were the primary focus; however, mutations at Leu 29, Val 68, and Ile 107 were also examined. Formation of the spectroscopically distinguishable heme intermediate (I') of deoxyMb was tracked as a function of pH and guanidinium chloride (GdmCl) concentration. The appearance of this intermediate signals cleavage of the iron-proximal histidine (His 93) bond. The key observations are as follows. (1) None of the distal heme pocket mutations investigated alter the nature of the heme intermediates that are formed under low pH unfolding conditions. (2) Unfolding of deoxyMb at high concentrations of GdmCl proceeds through the same heme intermediates that occur under low pH conditions. (3) The rate of the iron-histidine bond cleavage in an acidic medium is dramatically slowed when large hydrophobic residues (Leu and Phe) replace the distal histidine, whereas there is little correlation between the polarity of the residue at position 64 and the rate of denaturation by GdmCl. (4) However, apolar residues at position 64 enhance significantly the equilibrium resistance of deoxyMb to iron-histidine bond cleavage under both low pH and high GdmCl unfolding conditions. There is a direct correlation between the equilibrium pH and GdmCl values for maximum intermediate formation and the stabilities of the corresponding apoproteins. Collectively, these observations suggest that substantial unfolding of deoxyMb is required for Fe(II)-His 93 bond cleavage. Unlike the situation for aquometMb, heme loss from deoxyMb is not driven by protonation of the proximal histidine ligand. Instead, the process is mediated by more global unfolding of the protein that leads to solvation of the prosthetic group.

Inhibition by piroxicam of oxidative DNA damage, liver cirrhosis and development of enzyme-altered nodules caused by a choline-deficient, L-amino acid-defined diet in rats

Previously, we have reported that aspirin, a cyclooxygenase (COX) inhibitor, can prevent the fibrosis, cirrhosis and generation of oxidative DNA damage, and the associated development of glutathione-S-transferase placental form (GST-P)-positive preneoplastic liver nodules, caused by a choline-deficient, L-amino acid-defined (CDAA) diet in rats. In the present study, in order to elucidate the role of COX pathway in liver lesion-induction by a CDAA diet, the modulatory effects of other distinct chemical classes of COX inhibitors were examined. A long-acting example, piroxicam (PIRO) (at doses of 0.01, 0.02, 0.04 and 0.06%) and the short-acting ibuprofen (IBU) (at doses of 0.02, 0.04 and 0.06%) and indomethacin (IND) (at doses of 0.005 and 0.008%) were administered in the CDAA diet to male F344 rats, and animals were killed after 12 and 30 weeks. In another experiment, IND was given in drinking water at doses of 0.001, 0.002 and 0.004%. None of the inhibitors affected the development of fatty liver caused by a CDAA diet, but PIRO at doses higher than 0.04%, strongly inhibited the development of GST-P-positive and neoplastic nodules as well as fibrosis, cirrhosis and formation of 8-hydroxydeoxyguanosine (8-OHdG) adducts. IBU at the highest dose also exhibited similar but much less pronounced inhibitory effects. With IND, there was only a tendency for inhibition with no clear dose-dependence. The results together with our previous findings, indicate that relatively strong COX inhibitors, acting irreversibly like aspirin or for extended periods like PIRO, can prevent the endogenous hepatocarcinogenesis associated with a CDAA diet, although not the development of a fatty liver, suggesting that an augmented COX pathway might play key roles in the causation of liver lesions in this model.