Vacuolating toxin from Helicobacter pylori activates cellular signaling and pepsinogen secretion in human gastric adenocarcinoma cells

We investigated cellular signaling and pepsinogen secretion in the human gastric adenocarcinoma cell line AGS which was pretreated with the purified vacuolating cytotoxin from Helicobacter pylori. Results indicated that vacuolating toxin increased the levels of inositol phosphates, cytosolic free calcium concentration, adenosine 3',5'-cyclic monophosphate, and phosphorylation of 31 kDa and 22 kDa proteins in the host cells. Moreover, pepsinogen secretion from AGS cells was stimulated with increasing concentrations of cytotoxin. We conclude that besides the H. pylori cytotoxin-induced cellular vacuoles, cytotoxin-stimulated signaling mediators and pepsinogen release are important factors involved in the etiology of chronic active gastritis and peptic ulcer disease.

Helicobacter pylori induces gene expression in human gastric cells identified by mRNA differential display

Changes in gene expression patterns in gastric cells infected with Helicobacter pylori were characterized by means of mRNA differential display. Total RNA preparations were extracted from the H. pylori infected gastric cells and paired non-infected cells, and were probed with candidate clones identified after screening up to 6,000 mRNA species. Among them, four clones, 04G-1, 04G-2, 01G-1, and Cppa-2 show significant expression in the infected cells by Northern blot analysis, and they are 199 bp, 196 bp, 228 bp, and 276 bp in length, respectively. Database search revealed that nucleotide sequences of these clones share very low identity with any known sequence. These results indicate that H. pylori can significantly affect gene expression in gastric cells. Furthermore mRNA differential display can be used in pathogenesis studies to identify new genes in gastric cells in response to insults such as H. pylori.

Acute pancreatitis masquerading as testicular torsion

A 40-year-old man presented with fat necrosis of scrotum as the complication of acute pancreatitis. Excessive fluid accumulation in the pancreas and the extrapancreatic spaces, including around the spermatic cord, was seen on computed tomography. Surgical specimen showed typical fat necrosis of tunica vaginalis and the spermatic cord. After the surgery, pain of the testicle subsided completely, without recurrence. From the clinical presentation alone, it had been difficult to differentiate this patient's condition from torsion of the spermatic cord.

Inhibitory effect of crocetin on benzo(a)pyrene genotoxicity and neoplastic transformation in C3H10T1/2 cells

Crocetin is a major component in the fruit of Gardenia jasminoides Ellis, a Chinese herbal medicine. In the work, we investigate the protective action and mechanism against benzo(a)pyrene [B(a)P]-induced genotoxicity and neoplastic transformation with a non-toxic dose of crocetin (0.01-0.10 mM) for 1 hour prior to the administration of 0.1 mM B(a)P. B(a)P genotoxicity was inhibited significantly by crocetin in a dose responsive manner. Pretreating C3H10T1/2 cells with crocetin (0.1 mM) also caused a decrease in the covalent binding of B(a)P-diol-epoxide to DNA, to about half that of cells without crocetin treatment. Crocetin also inhibited B(a)P-induced transformations. When the culture was treated with crocetin (0.01, 0.05 and 0.10 mM) for 7 days, the transformation frequencies were lower than that of the culture without crocetin treatment. Furthermore, pretreating cells with crocetin (0.01-0.10 mM) also caused an increase in the activity of GSH S-transferase (GST) to 18-71% that of the cells without crocetin treatment. These results suggest that the inhibition by crocetin of B(a)P-induced genotoxicity and neoplastic transformation in C3H10T1/2 cells is due to a mechanism that increases the activity of GST and decreases the formation of a B(a)P-DNA adduct.

Determination of optimal liquid medium for enzyme expression by Helicobacter pylori

AIMS

To determine the best medium for the growth and enzyme expression of Helicobacter pylori.

METHODS

Twelve H pylori isolates from histologically confirmed infected patients were cultured on Brucella broth (BB), Brucella broth minus bisulphite (BLBB), and brain-heart infusion broth (BHIB), all supplemented with 5% (v/v) fetal calf serum. Growth rates and enzyme expressions of all H pylori isolates cultivated in these media were evaluated.

RESULTS

Although both BLBB and BHIB supported good growth of H pylori under microaerophilic conditions, the total protein content of H pylori detected was much higher with BHIB cultivation. Measurement of the specific activities of urease, phospholipase C, and sphingomyelinase for 12 H pylori isolates cultivated in these media, showed that BHIB supported the highest expression of these enzymes. Although BLBB supported better growth of H pylori than BB, it did not increase enzyme expression.

CONCLUSIONS

Cultivation of H pylori in BHIB is recommended for studies on the physiology, metabolism, and enzyme expression of the organism.

Structural requirements for the edema-inducing and hemolytic activities of mastoparan B isolated from the hornet (Vespa basalis) venom

Mastoparan B (MP-B) is a cationic tetradecapeptide isolated from the black-bellied hornet (Vespa basalis) venom. It has a primary structure (LKLKSIVSWAKKVL-CONH2) distinct from other vespine mastoparans. The peptide caused a dose-dependent swelling in rat hind paw and showed a potent hemolytic activity in guinea pig red blood cells. Studies on the structure activity relationship of the peptide showed that replacing lysine at position 2 (Lys2) by asparagine (Asn) in the MP-B sequence caused about 40% decrease in its edema-inducing activity at 50 micrograms/paw and 90% decrease in hemolytic activity at 30 microM of the peptide, while the same substitution at Lys4 did not cause a significant change in either activity. Replacing either Lys11 or Lys12 by leucine (Leu) caused little or no decrease in the edema-inducing and hemolytic activities. Decreases in both activities were observed when both Lys11 and Lys12 were replaced by Leu. On the other hand, replacing tryptophan at position 9 (Trp9) by tyrosine or phenylalanine in MP-B sequence almost abolished its hemolytic activity, while the edema-inducing activity was only partially inhibited. Circular dichroism spectra of the peptides measured in 20% trifluoro-ethanol revealed that substitution of Lys and Trp did not cause a significant change in the conformation of MP-B. it appears that Lys2 is crucial for both hemolytic and edema-inducing activities of MP-B, while Trp9 is of special importance to the hemolytic activity of MP-B. Lys11 and Lys12 in MP-B probably play a lesser role in both activities.

Generation and characterization of organ-tropism mutants of Japanese encephalitis virus in vivo and in vitro

Using gamma-ray irradiation, a pair of virulent (RP-9) and attenuated (RP-2ms) variants of Japanese encephalitis virus (JEV) were generated from a Taiwanese isolate, NT109. The two variants differed in plaque morphology, virus adsorption, and growth properties in BHK-21 cells: (i) RP-2ms produced smaller plaques than RP-9; (ii) RP-2ms adsorbed less efficiently to host cells but yielded a higher virus titer (burst size); and (iii) RP-2ms virions were mostly accumulated intracellularly, whereas RP-9 was released extracellularly. In addition, in an in vitro binding assay, the envelope (E) protein of RP-9, but not that of RP-2ms, bound specifically to a cellular protein of 57-kDa derived from BHK-21 cells. When injected into mice intracerebrally, RP-2ms was much less virulent than RP-9, with 50% lethal doses of > 10(7) and 0.4 plaque forming units, respectively. Moreover, when inoculated intraperitoneally, their organ tropism differed in that the main target organ for RP-2ms was liver, whereas that for RP-9 was brain. These results suggest that RP-2ms was less neurovirulent and less neuroinvasive from peripheral routes. Molecular analysis of the virus structural proteins detected only two differences between RP-9 and RP-2ms: one in E protein, Glu-138 in RP-9 and Lys-138 in RP-2ms, and the other in prM, Tyr-43 in RP-9 and His-43 in RP-2ms. Since the N-terminal 92 amino acids of prM are cleaved and not present in mature JEV virions, the single-amino-acid change of the E protein at position 138 may account for the difference between the mutants in the in vitro binding assay. Such mutation in E protein, or perhaps in conjunction with the prM mutation, may be responsible, in part, for the phenotypic differences observed in vitro and in vivo between the two mutants.

A highly attenuated strain of Japanese encephalitis virus induces a protective immune response in mice

A pair of virulent (RP-9) and attenuated (RP-2ms) mutants of Japanese encephalitis virus (JEV) were generated from a Taiwanese isolate NT109. The mutants differed in several aspects in vitro and in vivo. RP-2ms exhibited smaller plaque than RP-9 on BHK-21 cells, and when intracerebrally injected, RP-2ms was much less neurovirulent than RP-9. As peripherally inoculated, RP-2ms lost neuroinvasiveness while RP-9 penetrated blood-brain barrier, replicated in mouse brain, and killed all the mice. Single RP-2ms immunization completely protected C3H and ICR mice from a lethal challenge with RP-9; the sera from such mice contained antibodies against JEV envelope and nonstructural 1 proteins, indicating RP-2ms had replicated in the mice Neutralizing activity against NT109 in such sera was further demonstrated by plaque reduction neutralization test. In addition, significant lymphoproliferation was detected in spleen cells from the RP-2ms-immunized mice, and cytotoxic activity in these cells specific for the MHC-matched, JEV-infected cells, but not mock cells, was also observed. Altogether, these results demonstrate that RP-2ms, a highly attenuated JEV strain, can induce a protective immunity in mice.

Dissection of functional domains of the human DNA replication protein complex replication protein A

Replication protein A (RPA) is a mammalian single-stranded DNA binding factor essential for DNA replication, repair, and recombination. It is composed of three subunits of 70, 34, and 13 kDa (Rpa1, Rpa2, and Rpa3, respectively). Deletion mapping of the Rpa2 subunit identified the domain required for interaction with Rpa1 and Rpa3 which does not include the N-terminal domain that is phosphorylated during S phase. Deletion mapping of Rpa1 defined three domains. The C-terminal third of the Rpa1 polypeptide binds Rpa2 which itself forms a bridge between Rpa1 and Rpa3. The N-terminal third of Rpa1 bound single-stranded DNA under low stringency conditions only (0.1 M NaCl), while a central domain binds to single-stranded DNA under both low and high stringency conditions (0.5 M NaCl). Binding to p53 requires the N-terminal third of Rpa1 with some contribution from the C-terminal third. The evolutionarily conserved putative zinc finger near the C terminus of Rpa1 was not required for binding to single-stranded DNA, Rpa2, or p53. However, all three subdomains of Rpa1 and the zinc finger were essential for supporting DNA replication in vitro. These experiments are a first step toward defining peptide components responsible for the many functions of the RPA protein complex.

Persistence of Japanese encephalitis virus is associated with abnormal expression of the nonstructural protein NS1 in host cells

Persistent infection with Japanese encephalitis virus (JEV) was established in murine neuroblastoma N18 cells, and the persistency has been maintained in cell culture for over 6 months. From the persistently infected cells, a clone named C2-2 was selected and expanded to form a stable cell line. The vast majority of C2-2 cells showed viral protein staining by immunofluorescence and continuously produced low levels of virus (10(3) to 10(4) PFU/ml) without marked cytopathic effects or cyclic variations. In addition to the wild-type viral proteins, truncated forms of the viral nonstructural protein 1 (NS1) as well as its derivative NS1' were produced in C2-2 cells. Both truncated NS1 and NS1' contain deletions at their N-termini; however, the analyses by RT-PCR and direct sequencing of the viral RNA failed to detect any truncations or mutations within the NS1 region, suggesting that NS1 truncation was a result of a unique posttranslational proteolytic cleavage of NS1 in the persistently infected cells. Similar but not identical truncation of NS1 was also observed in two other persistently infected cell lines established in Vero and DBT (murine astrocytoma) cells. However, viruses released from C2-2 cells did not produce truncated NS1 upon infection of N18 cells, suggesting that NS1 truncations were the result of virus-cell interaction in persistently infected cells. These data indicate a strong association between abnormal NS1 expression and JEV persistency. A probable involvement of dysfunctional NS1 in the establishment and/or maintenance of JEV persistency in tissue culture is discussed.

Immunogenicity of mastoparan B, a cationic tetradecapeptide isolated from the hornet (Vespa basalis) venom, and its structural requirements

Mastoparan B (MP-B) is a cationic tetradecapeptide (LKLKSIVSWAKKVL-CONH2, mol. wt 1611) isolated from the black-bellied hornet (Vespa basalis) venom. The small peptide itself was capable of inducing antibodies without prior conjugation to a protein carrier in rabbits and mice. The mouse antibody was found to be of IgG1 isotype with kappa-type light chain. The peptide antigen was able to form insoluble complexes with the specific antibody, suggesting that MP-B possessed more than one epitope in its molecule. The finding that MP-B was able to bind with both mouse and rabbit antibodies in sandwich ELISA supports this contention. Synthetic MP-B analogues in which lysine at position 2, 4, 11 or 12 was replaced by neutral amino acids such as asparagine or leucine showed a significant decrease in their antibody-binding activities. Substitution of lysine at position 4 (Lys4) caused the most marked inhibition in its binding activity. However, replacing tryptophan at position 9 by tyrosine caused a relatively small reduction in its binding activity. Replacing both Lys2,4 by asparagine or removing Lys-containing segments at amino or carboxyl terminus in MP-B sequence caused a remarkable decrease in the antibody-binding and immunogenic activities of the peptide. The Lys residues located at amino and carboxyl terminal segments of MP-B, especially Lys4, appear to play a critical role in the binding interaction and the immunogenicity of the peptide.

N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine. A new genotoxic agent derived from the reaction of tyrosine and glucose in the presence of sodium nitrite

N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine (NO-NTA) is a product of a model browning system in the presence of sodium nitrite. In this study, the chemical structure is confirmed by spectral studies, including UV, mass spectrometry, nuclear magnetic resonance and infrared spectroscopy. NO-NTA is strongly genotoxic to the rat hepatocyte and is moderately cytotoxic to mouse C3H10T1/2 cells. Results obtained in this study indicate that NO-NTA inflicted DNA damage through the formation of a DNA adduct. In addition, C3H10T1/2 cells were treated with NO-NTA and, following addition of 12-O-tetradecanoylphorbol-13-acetate (TPA) as promotor, the increase of transformed foci indicated that NO-NTA could possibly be an initiator [corrected] of TPA tumor promotion. A transformed cell line from NO-NTA initiated and TPA promoted foci increased saturation density and growth ability in soft agar reactive to the control line. These results suggest that the formation of a genotoxic agent of nitroso-derivatives may take place in a nitrite-containing food system during processing and cooking.

Antioxidant properties of demethyldiisoeugenol

The antioxidant properties of demethyldiisoeugenol were investigated in this study using various models. Demethyldiisoeugenol inhibited Fe(2+)-induced lipid peroxidation in rat brain homogenate in a concentration-dependent manner with an IC50 1.8 +/- 0.1 microM. Demethyldiisoeugenol was more effective than alpha-tocopherol and BHT in reducing the stable free radical diphenyl-2-picrylhydrazyl (DPPH). It also scavenged superoxide anion generated by xanthine/xanthine oxidase and peroxyl radical (ROO.) derived from 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) in aqueous system with a stoichiometric factor of 1.3 +/- 0.2. Furthermore, it prevented conjugated-diene formation and apolipoprotein B (apo B) oxidation of LDL. However, demethyldiisoeugenol did not scavenge 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN)-derived peroxyl radical in hexane. It also did not chelate Fe2+, did not inhibit xanthine oxidase activity or possessed hydroxyl radical (.OH) scavenging activity. Experimental results indicate that demethyldiisoeugenol is a potentially effective antioxidant and can protect rat brain homogenate and LDL against oxidation.

Phenotypic and functional analysis of natural killer cells in systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) manifested with multiple autoantibodies production and glomerulonephritis, is the best example of systemic autoimmune diseases. To further elucidate the role of cytokines and the potential involvement of natural killer cells (NK cells) in the pathogenesis of lupus, phenotypic analysis of peripheral blood mononuclear cells (PBMC), NK cells cytotoxicity and cytokines production pattern of SLE patients and normal controls were examined. In addition, the effect of a variety of cytokines on anti-dsDNA antibodies production was also investigated. Our results showed that: (a) there was an increased percentage of memory T cells and decreased percentage of NK cells in SLE patients when compared to normal controls (p < 0.05); (b) a decreased production of cytokines like gamma-IFN in mitogen-stimulated PBMCs was also noted in SLE patients; (c) cytolytic activity of NK cells was markedly reduced in SLE patients (p < 0.05); (d) spontaneous secretion of IgG anti-dsDNA antibodies by B cells isolated from SLE patients could be inhibited by gamma-IFN, but not by IL-2, IL-4 and IL-5. These data suggested that decreased functions of NK cells and related type 1 T helper cells be closely related to the immune dysregulation and autoantibodies production in SLE.

Five new pregnane glycosides from Cynanchum taiwanianum

Five new pregnane glycosides, taiwanosides A [1], B [2], C [3], D [4], and E [5], together with wilfosides C1N [6], C2N [7], M1N [8], and K1N [9], were isolated from the roots of Cynanchum taiwanianum. Their structures were determined on the basis of spectroscopic and chemical evidence.

Differential pathways of insulin action upon the hepatitis B surface antigen gene expression and cell proliferation in human hepatoma cells

We have shown previously that insulin at the physiological concentration suppresses hepatitis B surface antigen (HBsAg) gene expression in cultured human hepatoma Hep3B cells, and this suppression phenomenon is concomitant with the stimulation of cell proliferation. We have now examined whether these two distinct insulin actions on the Hep3B cells are mediated through the same or different signaling pathways. After prolonged treatment with high concentration of tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA), the protein kinase C-alpha (PKC-alpha) level in the Hep3B cells was diminished and could not be detected by Western blot analysis. Under this condition, TPA treatment has no effect on the number or affinity of the insulin receptor on Hep3B cells. However, insulin-stimulated cell proliferation was completely abolished in the PKC-alpha depleted cells. In contrast, insulin still suppressed HBsAg gene expression with the same ED50 (approximately 0.5 nM) as the control cell. The induction of proto-oncogene egr-1 (early-growth-regulatory-1) by insulin and TPA under similar conditions were also examined. Both insulin and TPA stimulated egr-1 gene expression up to 10-fold in the control cell, but neither of these two agents showed any effect on egr-1 gene expression in the PKC-alpha down-regulated Hep3B cells. These observations indicate that the PKC-alpha may be involved in the insulin induced egr-1 expression and cell proliferation but not in the insulin suppressed HBsAg gene expression in human hepatoma cells.

Generation and characterization of Japanese encephalitis virus specific monoclonal antibodies

Monoclonal antibodies (MoAbs) specifically against Japanese encephalitis virus (JEV) were generated by fusion of immunized mouse spleen cells with NS-1 myeloma cells. Nakayama-NIH (Na) and three Taiwan local strains of JEV, i.e., TL isolated from a patient's brain in 1965, NT109 (JE7) isolated from Cx. tritaeniorhynchus in 1985, and RP9, a plaque purified clone of NT109, were used in the immunization. The specificities of moAbs were determined by immunoprecipitation and western blotting, using JEV-infected cell lysates. They were confirmed by the same methods using recombinant JEV proteins as antigens. From Na immunization, 4 anti-E, 3 anti-NS1 and 3 anti-NS3 moAbs were generated. Seventeen anti-E, three anti-NS1 and three anti-NS3 specific moAbs were generated from mice immunized with Taiwan local JEV strains. Overall 21 anti-E, 6 anti-NS1, and 6 anti-NS3 moAbs were produced and characterized. The isotypes of these moAbs were also determined and described. Interestingly, a majority of the moAbs generated for RP9 were IgG1 isotype. In conclusion, 33 moAbs specific to JEV were generated and characterized, and some of these anti-JEV moAbs were made against Taiwan local isolates. These moAbs provide a powerful tool to study JEV, especially the antigenic properties of Taiwan's local strains.

[Regulatory effect of ventral tegmental area on sleep-wakefulness in rats]

Experiments were performed on 31 male SD rats. The results were as follows: (1) The time of waking was increased during the second and third hours after microinjection of 3.3 and 6.6 nmol bromocriptine into bilateral VTA (P < 0.01), but the 1.33 nmol group was without significant effect. (2) The time of waking was decreased during the second and third hours after microinjection of 2 and 4 nmol SCH23390 into VTA (P < 0.01 and P < 0.05 respectively), while 3.4 nmol sulpiride group was without effect. (3) One week after administration of kainic acid (0.3 microgram), the rats presented less time of waking in the day (P < 0.05), while sleep-wakefulness cycle at night showed no change. The results suggest that bromocriptine could increase wakefulness by activating VTA DA neurons via D1 receptor and that the DA neurons might exert a tonic effect for maintaining the wakefulness at the daytime.

Antibodies in serum of patients with clonorchiasis before and after treatment

Sera of 31 patients infected with Clonorchis sinensis were examined using fraction 1 antigen by ELISA during a one-year observation. The results of ELISA with Igs, IgG and IgA demonstrated high sensitivity (100%, 100% and 90%) and specificity (100%, 100% and 87%). Sera specific Igs and IgG were significantly decreased in the 3rd month after treatment with praziquantel (25mg/kg body weight in one dose), and IgA was significantly decreased in the 1st month (paired t-test, p < 0.05). No eggs were found in the stool after treatment. Detection of sera specific Igs, IgG and IgA by ELISA was combined with stool examination to evaluate the effect of praziquantel and the completeness of the cure.

Immunization with nonstructural proteins E1 and E2 of cottontail rabbit papillomavirus stimulates regression of virus-induced papillomas

Cottontail rabbit papillomavirus is the major animal model for cancer-associated papillomaviruses. Here we show that vaccination with the nonstructural proteins E1 and E2 induces the regression of virus-induced papillomas and that vaccination is equally effective when proteins are given with and without adjuvant. There was no correlation between antibody levels and regression, suggesting that tumor regression may be due to a cell-mediated response.

Mutagenicity and cytotoxicity of nitropyrrole compounds derived from the reaction of 2-acetyl pyrrole with nitrite

2-Acetylpyrrole (AP) is a product of model browning systems, and has been isolated as a major flavour component of many foods. Reaction of AP with nitrite produces two N-nitropyrrole compounds, 1-nitro-2-acetyl-pyrrole (NAP) and 1,3,5-trinitro-2-acetylpyrrole (TNAP), the chemical structures of which have been confirmed by spectral studies, including UV mass, nuclear magnetic resonance, infra-red and elemental analysis (EA). NAP and TNAP are moderately mutagenic to the Salmonella strains TA98 and TA100 in the absence of a mammalian activation system and are markedly cytotoxic to mouse C3H10T1/2 cells. These results suggest that the formation of direct-acting mutagens of nitro-derivatives may take place in nitrite-containing food or in vivo by nitrosation following ingestion of AP.

Cardiovascular effects of mastoparan B and its structural requirements

Mastoparan B is a cationic, amphiphilic tetradecaeptide (LKLKSIVSWAKKVL-CONH2) isolated from the venom of the hornet Vespa basalis. Intravenous injection of the peptide into rats caused a profound depression of blood pressure and cardiac function, which was inhibited by cyproheptadine, reserpine and multiple doses of compound 48/80, but not by diphenhydramine and cromolyn. Mastoparan from Paravespula lewisii showed little cardiovascular inhibitory activity. A synthetic mastoparan B analog in which lysine at position 2 was replaced by asparagine showed a marked decrease in the cardiovascular depressor effects, while replacing lysine at position 4, 11 or 12 with leucine did not cause a significant reduction in these effects. Replacing lysine at position 12 with leucine even caused a more sustained depressor effect. However, the analog in which lysines at positions 11 and 12 were replaced by leucine lost its cardiovascular inhibitory activity. Replacing tryptophan at position 9 with phenylalanine in mastoparan B did not affect its activity. It is concluded that mastoparan B is involved in the cardiovascular disturbances induced by the hornet venom. Lysine at position 2 is a critical residue for the cardiovascular effects of mastoparan B. A peptide molecule with two lysine residues, one located close to the amino terminus and the other near the carboxyl end of the peptide, appears to be the optimal structure for eliciting the cardiovascular depressor effects.

T-cell response to cottontail rabbit papillomavirus structural proteins in infected rabbits

Cottontail rabbit papillomavirus (CRPV)-induced papillomas progress at a high frequency to carcinomas and thus can serve as a model for high-cancer-risk human papillomavirus infection. Previously, we have shown that antibodies to nonstructural and structural proteins are detected in only a fraction of papilloma-bearing animals. However, the antibody response to structural proteins drastically increases as papillomas progress to carcinoma (Y.-L. Lin, L. A. Borenstein, R. Selvakumar, R. Ahmed, and F. O. Wettstein, J. Virol. 67:382-389, 1993). Here we have monitored the cellular immune response to viral proteins during the course of infection and particularly during progression from papilloma to carcinoma. This was done by measuring the in vitro proliferation response of peripheral blood mononuclear cells (PBMCs) to CRPV structural proteins L1 and L2. The proliferating cells were identified as T cells by selective removal of B or T cells. In general, the T-cell response was low for rabbits at the papilloma stage and none responded to L2. Lymphocytes from animals with carcinomas more frequently and more strongly responded to L1, and more than half also responded to L2. In addition to stimulation of PBMCs, L1- and L2-specific proliferation could also be demonstrated with lymph node and spleen cells. Overall, our data show that progression of papilloma to carcinoma is associated with an increased T-cell response to CRPV structural proteins in addition to an increased humoral response. This greater immune reactivity, however, was not associated with a selectively increased expression of structural proteins, since RNA isolated from papillomas and carcinomas contained similar relative levels of late and early RNA as shown by dot blot analysis. Thus, the heightened immune reactivity seen in carcinoma-bearing rabbits most likely reflects greater stimulation of the immune system owing to dissemination of the tumor. These findings suggest that increased immune responses to papillomavirus proteins may be prognostic of progression to carcinoma and particularly of the development of metastases.

Antiplatelet and vasorelaxing actions of the acetoxy derivative of cedranediol isolated from Juniperus squamata

The antiplatelet and vasorelaxing actions of 14-acetoxycedrol, an acetyl derivative of the sesquiterpene 8,14-cedranediol isolated from Juniperus squamata Hayata, were investigated in washed rabbit platelets and rat aorta, respectively. 14-Acetoxycedrol inhibited the aggregation and ATP release of rabbit platelets induced by ADP, arachidonic acid, platelet-activating factor (PAF), collagen, and thrombin. Prolongation of the incubation time of 14-acetoxycedrol with platelets did not cause further inhibition and the aggregability of the treated platelets could be restored after washing of the platelets. It inhibited thromboxane B2 formation of washed platelets caused by arachidonic acid, collagen, and thrombin in a concentration-dependent manner. The formation of inositol phosphate caused by collagen and PAF was inhibited by 14-acetoxycedrol, while that caused by thrombin was not affected. 14-Acetoxycedrol markedly inhibited the intracellular calcium rise caused by PAF, and slightly inhibited that caused by thrombin in quin-2/AM-load platelets. In rat thoracic aortae, 14-acetoxycedrol inhibited the high K+ (60 mM) and Ca2+ (0.03-3 mM) induced cumulative contractions in a concentration-dependent manner, while it did not affect the phasic and tonic contractions elicited by norepinephrine. The tonic contractions elicited by KCl (60 mM) and Bay K 8644 were also relaxed by 14-acetoxycedrol. It is concluded that the antiplatelet effect of 14-acetoxycedrol is due to the inhibition of thromboxane formation and phosphoinositides breakdown and the vasorelaxing action of 14-acetoxycedrol is due to inhibition of Ca2+ influx through the voltage-dependent Ca2+ channel.

Inhibition of platelet thromboxane formation and phosphoinositides breakdown by diisoeugenol

Diisoeugenol inhibited the platelet aggregation and ATP release of rabbit platelets caused by ADP, arachidonic acid, platelet-activating factor (PAF), collagen and thrombin. Prolongation of the incubation time of platelets with diisoeugenol did not cause further inhibition and the aggregability of platelets could not be restored after washing. In human platelet-rich plasma, diisoeugenol inhibited the biphasic aggregation and ATP release induced by adrenaline and ADP in a concentration-dependent manner. Thromboxane B2 formation caused by arachidonic acid, collagen and thrombin was markedly inhibited by diisoeugenol in a concentration-dependent manner. Diisoeugenol also inhibited the formation of inositol monophosphate caused by collagen, PAF and thrombin. The cAMP level of washed platelets was not changed by diisoeugenol. It is concluded that the antiplatelet effect of diisoeugenol is due to the inhibition of thromboxane formation and phosphoinositides breakdown.

[Effects of bromocriptine microinjection into VTA on the DOPAC level in nucleus accumbens]

The experiment was performed in sodium pentobarbital anesthetized male SD rats. In vivo differential pulse voltammetry (DPV) was used to monitor a metabolite of dopamine-3,4-dihydroxyphenylacetic acid (DOPAC) level in the ipsilateral nucleus accumbens following microinjection of bromocriptine (2.5 micrograms/0.5 microliters, n = 5) into left ventral tegmental area (VTA). The results indicated that after microinjection the amplitude of DOPAC peak increased gradually and reached to 128% and 143% compared to the control at the 50th and 80th min respectively (P < 0.01). The duration of the effect was about two hours. One hundred and eighty min after injection, the amplitude of DOPAC decreased to 111% of control (P > 0.05). SCH23390 (2 nmol/0.5 microliters, n = 4), a selective D1 antagonist was given into left VTA 40 min prior to microinjection of bromocriptine. In this group, the above-mentioned effect of bromocriptine was blocked, the amplitude of DOPAC peak showed no increase. The results suggest that the microinjection of bromocriptine into VTA induces an increase of activity of mesolimbic dopaminergic neurons probably mediated by D1 receptor.

Daphnoretin, a new protein kinase C activator isolated from Wikstroemia indica C.A. Mey

Daphnoretin, a biologically active principle isolated from Wikstroemia indica C.A. Mey., caused platelet aggregation in washed rabbit platelets, platelet-rich plasma and whole blood. The aggregation of and ATP release from platelets induced by daphnoretin were similar to phorbol ester- and diacylglycerol-induced aggregation and release. The EC50 values of daphnoretin-, phorbol 12,13-dibutyrate (PDBu)- and 1-oleoyl-2-acetylglycerol (OAG)-induced platelet aggregation in washed rabbit platelets were 17.2 +/- 2.8 microM, 20.6 +/- 2.1 nM and 38.6 +/- 1.7 microM respectively. Platelet aggregation induced by daphnoretin and PDBu was not inhibited by indomethacin, BN52021 or sodium nitroprusside. ADP-scavenging systems, apyrase and phosphocreatine/creatine kinase, showed weak inhibition of the aggregation, and EGTA, triflavin, verapamil and prostaglandin E1 markedly inhibited the aggregation. Staurosporine, a potent protein kinase C inhibitor, suppressed daphnoretin-, PDBu- and OAG-induced aggregation and ATP release in a concentration-dependent manner. The IC50 values of staurosporine on daphnoretin (50 microM)-, PDBu (100 nM)- and OAG (50 microM)-induced aggregation were 37.7 +/- 8.3, 52.2 +/- 6.3 and 42.8 +/- 8.9 nM respectively. Daphnoretin did not cause significant thromboxane B2 formation in rabbit platelets. Neither daphnoretin nor PDBu caused [3H]inositol monophosphate formation or an increase in intracellular Ca2+ concentration in myo-[3H]inositol-labelled and Fura-2-loaded platelets. Platelet cytosolic protein kinase C was activated by daphnoretin and PDBu in a concentration-dependent manner with an EC50 of 12.4 +/- 1.2 microM and 18.7 +/- 1.4 nM respectively. Membrane-associated protein kinase C activity was increased by either daphnoretin or PDBu. [3H]PDBu binding to washed rabbit platelets was inhibited by daphnoretin in a concentration-dependent manner with an IC50 value of 45.2 +/- 5.2 microM. These results indicate that daphnoretin is a protein kinase C activator in rabbit platelets.

The skin, tongue, and brain as favorable organs for hog cholera diagnosis by immunofluorescence

Hog cholera virus antigens were found densely distributed in skin and tongue of pigs experimentally infected with hog cholera virus. The finding described here warrants the usage of ear biopsies for hog cholera diagnosis on a herd basis.

Cottontail rabbit papillomavirus L1 protein-based vaccines: protection is achieved only with a full-length, nondenatured product

Papillomas induced by the cottontail rabbit papillomavirus (CRPV) progress at a high frequency to carcinomas. In this regard, CRPV and its tumors can serve as an animal model for highly oncogenic human papillomaviruses. We have previously shown that immunization with major structural protein L1 elicits neutralizing antibodies and protects rabbits from papilloma development (Y.-L. Lin, L.A. Borenstein, R. Selvakumar, R. Ahmed, and F.O. Wettstein, Virology 187:612-619, 1992). In this study, we demonstrated that vaccination with the TrpE-L1 fusion protein not only protected rabbits from papilloma development but also prevented latent infection. This was indicated by the failure to amplify CRPV sequences by polymerase chain reaction in biopsies from infection sites of immunized animals. Furthermore, we showed that TrpE-L1 immunization protected rabbits from papilloma formation induced by virus but not from that induced by viral DNA. To explore the possibility of developing vaccines based on L1 subfragments, we mapped the linear L1 epitopes recognized by TrpE-L1-immunized rabbits and by virus-infected rabbits resistant to superinfection. Sera from papilloma-bearing rabbits reacted with one major epitope located at the carboxy-terminal end of L1, between amino acids (aa) 480 and 505. A second epitope, and in some animals a third one, was located in the amino-terminal region, between aa 78 and 101, as well as between aa 37 and 62. Sera from TrpE-L1-immunized animals recognized only one major epitope, located between aa 6 and 37. Immunization of rabbits with L1 subfragment fusion proteins led to seroconversion, but no neutralizing antibodies were produced and the animals were not protected against papilloma formation. The data indicate that a successful papillomavirus vaccine must be based on immunization with full-length native L1 and that further simplification to smaller peptides containing major linear epitopes is not feasible.

[Uses of monomolecular lipid film for control of udo aphid (Toxoptera odinae (Van der Goot))]

The biological character of udo aphid was observed and monomolecular lipid film was used to control it. The results showed that at 100 and 200 times the lipid film, the hatch rate of over-winter eggs was lower than the control by 30.76% and 12.15% respectively, and at 50, 100 and 200 times the lipid film the mortality of young nymph aphids was 100% and those of old nymph aphids and adult aphids were 8.31%, 32.62% and 3.31% respectively.

Progression from papilloma to carcinoma is accompanied by changes in antibody response to papillomavirus proteins

Cottontail rabbit papillomavirus induces benign tumors, papillomas, in rabbits which progress at a high frequency to malignant tumors, carcinomas. Cottontail rabbit papillomavirus therefore provides an experimental model for oncogenic human papillomaviruses. The nature of the antigens recognized by the host has not been identified at any stage of tumor development. Here, we characterized the humoral immune response to viral antigens in cottontail and domestic rabbits at the papilloma stage, in domestic rabbits at the carcinoma stage, and in animals in which papillomas had regressed. Antibodies to linear epitopes were identified by Western blotting (immunoblotting) with bacterial fusion proteins, and evidence for recognition of conformational epitopes was obtained by immunoprecipitation. An immune response to the early proteins E1, E2, E6, and E7 was detected only in a fraction of the animals, and all animals were negative for E4 and E5. The response to E6 and E7 peaked around 7 months and then decreased, while that to E1 and E2 remained level after an initial raise. The antibody response to structural proteins was low at the papilloma stage, and antibodies to L1 recognized predominantly conformational epitopes. As papillomas progressed to carcinomas, there was a drastic increase in the response to L1 and L2, suggesting a change in interaction between virus-infected host cells and the host's immune system.

Activation of human platelets by the rabbit anticardiolipin antibodies

Affinity purified anticardiolipin antibodies (ACLA) raised in rabbits showed cross-reactivities with various negatively charged phospholipids as shown by both the solid phase enzyme-linked immunosorbent assay (ELISA) and inhibition studies. In ELISA, ACLA showed strong cross-reactivity to both sphingomyelin (SM) and phosphatidylethanolamine (PE), but the inhibition studies showed that ACLA failed to bind the aqueous suspensions of SM, PE, and PE/PC (1:1). ACLA bound to resting gel-filtered human platelets (GFP) as shown by both inhibition study and flow cytofluorometric analysis. Western blotting procedure showed that ACLA strongly cross-reacted to an 80-Kd plasma membrane protein. ACLA activated platelet response in a concentration-dependent manner. At less than 10 micrograms/mL, ACLA induced both platelet shape change to spiculate irregular forms as shown by scanning electron microscopy and the phosphorylation of 20-Kd protein. ACLA at more than 10 micrograms/mL caused platelet aggregation and secretion. The aggregation was inhibited by EDTA; aspirin; antimycin A plus 2-deoxyglucose; PGE1; and the F(ab')2 fragment of ACLA. It was not inhibited by monoclonal antibody to Fc receptor (MoAb FcR2). The biochemical events of ACLA-induced platelet response involved the elevation of (1) thromboxane A2 formation, (2) cytosolic free calcium ion concentration ([Ca2+]i), and (3) 47-Kd protein phosphorylation. In addition, the subaggregatory concentration of ACLA showed synergistic platelet activation with that concentration of thrombin, collagen, and epinephrine. The study showed the mechanism involved in ACLA-induced platelet responses.

Antitumor effects of new-type recombinant interleukin-2

Two new human recombinant interleukin-2 (rIL-2), 125-Ser-rIL-2, and 125-Ala-rIL-2, were generated by protein engineering technique. Both of them maintained the proliferation of natural killer (NK) cells, CTLL-2 cells and their long-term propagations. The mutated new rIL-2 also enhanced the bioactivity of NK cells and the cytotoxicity of tumor-infiltrating lymphocytes (TIL) against the target tumor cells. The above results were all compared with that of the native rIL-2 and a similarity between them was found, which indicates that new type rIL-2 could be used for adoptive immunotherapy of malignant diseases.

Effective vaccination against papilloma development by immunization with L1 or L2 structural protein of cottontail rabbit papillomavirus

Immunization of rabbits with either L1, the major structural protein, or L2, a minor structural protein of cottontail rabbit papillomavirus (CRPV), protected against challenge with the virus. Neutralizing antibodies were elicited by both the L1 and L2 trpE fusion proteins. Neutralization with anti-L1 serum, however, was more efficient than with anti-L2 serum. In contrast, when tested on Western blots the immune response to L2 was stronger than to L1. Rabbits were also protected against CRPV infection by immunization with L1 expressing recombinant vaccinia virus. Sera from two of three rabbits immunized with recombinant vaccinia virus were negative on Western blots but all three were positive in ELISA's with nondenatured fusion protein or in immunoprecipitations. The results suggest that both the viral structural proteins, L1 and L2, merit consideration in the development of a vaccine against papillomavirus.

Identification of three transforming proteins encoded by cottontail rabbit papillomavirus

Cottontail rabbit papillomavirus (CRPV) provides an animal model for human papillomaviruses associated with a high risk of cancer development. So far, nothing is known about the transforming functions of CRPV genes because of the lack of an assay system. We have recently developed two systems to assay for CRPV transforming functions. One is based on the finding that transformation of NIH 3T3 cells by CRPV is considerably increased by deleting sequences in open reading frame L2. The second one is based on the use of a cottontail rabbit skin epithelial cell line, sf1Ep (C. Meyers and F. O. Wettstein, Virology 181:637-646, 1991). Mutations were introduced which abolished expression of the full-length E6 protein (LE6), the short E6 protein (SE6) initiated at the second ATG of E6, the E7 protein, or the E5 protein. Mutations affecting LE6 or E7, but not SE6, reduced transformation of NIH 3T3 and sf1Ep cells. Transformed NIH 3T3 cell lines with mutations in LE6 and E7 did not grow in soft agar, while those with mutations in SE6 and E5 grew with a reduced efficiency. The cell lines with mutations in LE6, SE6, or E7 still did induce tumors in nude mice. These mutations, however, abolished the ability to induce papillomas in rabbits. When expressed individually with a retroviral vector, LE6, SE6, or E7, but not E5, conferred anchorage-independent growth. The level of viral protein expression in these cell lines was generally low, and a comparison of the abundance of virus-specific mRNA showed that cell lines contained 20 to 50 times less mRNA than a cottontail rabbit papilloma. These data demonstrate that CRPV encodes at least three transforming proteins.

Proopiomelanocortin (POMC)-derived peptides and sleep in the rat. Part 2--Aminergic regulatory processes

Apomorphine (Apo), a D1/D2 Dopamine (DA) agonist, at high doses (500 micrograms/kg) induces a short-lasting insomnia, antagonized by a secondary injection of corticotropin-like intermediate lobe peptide (CLIP, 10 ng); these effects are also observed with hypophysectomized (hypoX) rats. The administration of the serotonin (5-HT) agonist 8-hydroxy-2-di-n-propylamino-tetralin (8-OHDPAT, 0.3 mg/kg) induces also an insomnia which, unlike Apo, is followed by a significant PS rebound. CLIP, again, antagonizes the 8-OHDPAT-induced insomnia. Finally, Bromocriptine (5 mg/kg), an agonist for both DA and 5-HT, induces first an insomnia (antagonized by CLIP), followed by a PS rebound; these effects persist in hypoX rats.

[Immunological screening of clonorchiasis]

Crude antigens of Clonorchis sinensis adult worms were purified by Sephadex G-200 column chromatography. A purified antigen was then applied to detect clonorchiasis patients and parasite-free subjects by an enzyme-linked immunosorbent assay (ELISA) and an intradermal test (IDT). The results of the ELISA showed that specific antibody levels of IgG, IgM, IgA, IgE and total IgE in 371 infected patients were significantly higher than those of 181 parasite-free subjects (Student's t-test, p less than 10(-6) or p less than 0.005). The sensitivity was 92.8% and the specificity was 89.0%. Significant correlations between the intensity of infection, expressed as egg per gram feces, and specific IgG, IgA and total IgE concentration were observed (linear regression, p less than 0.0005). Among the 309 subjects tested intradermally with Clonorchis antigen, 128 showed a positive reaction while all of the 60 parasite-free subjects showed negative results. By this test, the sensitivity was 49% and the specificity of IDT was 100%. The specific IgG, IgA and total IgE antibody levels of the IDT positive patients were significantly higher than those of the negative subjects (Student's t-test, p less than 0.0005). There was no correlation between the induced swelling diameter and the intensity of infection in IDT positive clonorchiasis patients. Cross reactions in ELISA were observed in patients infected with Capillaria philippinensis, Sparganum proliferum and Toxocara canis, when the antigens prepared in the present study were used.

Influence of long-term continuous illumination on the nuclear volume of hypothalamic neurons in female rats

A light microscopic quantitative analysis was performed for studying the effects of long-term exposure to continuous illumination on hypothalamic morphology in female rats. Nuclear volumes of neurons in the suprachiasmatic nucleus, paraventricular nucleus, ventromedial nucleus and preoptic area were measured in 16-18 month-old Long-Evans female rats which had been exposed to continuous light for 11 months. Significant nuclear volume shrinkage could be observed in all investigated regions except for the preoptic area in these animals when compared to that of control rats kept under a photoperiod of 14h light and 10h dark. The relationship between morphological changes of hypothalamic neurons and the marked alteration of melatonin and estrogen levels induced by long-term exposure to continuous light is discussed.

An acute pleuropneumonia in a pig caused by Chromobacterium violaceum

A 2.5-month-old, 30 kg Duroc pig died 10 days after showing clinical signs of dyspnoea and diarrhoea. Acute necrotizing and fibrinous pleuropneumonia with locally extensive lesions was found. Chromobacterium violaceum was isolated from pneumonic lung tissues and intratracheal inoculation of a pure culture into two SPF pigs reproduced lesions similar to those found in the natural infection.

Effect of transmural versus nontransmural myocardial infarction on inducibility of ventricular arrhythmias during sympathetic stimulation in dogs

Transmural myocardial infarction interrupts sympathetic nerves and denervates viable muscle distal to myocardial infarction. The effect of sympathetic stimulation on responses to programmed ventricular stimulation was studied in dogs without myocardial infarction (Group I: n = 5), with transmural anterior wall myocardial infarction (Group II: n = 6) and with nontransmural anterior wall myocardial infarction (Group III: n = 9). Ventricular effective refractory period during sympathetic stimulation decreased by 16 +/- 18, 1 +/- 2 and 12 +/- 8 ms (mean +/- SD) in viable muscle of the inferoapical left ventricle in Groups I, II and III, respectively, suggesting efferent sympathetic denervation by transmural myocardial infarction only. Sustained ventricular tachycardia or fibrillation was induced more easily during sympathetic stimulation in six of the six dogs with transmural infarction, but in only two of the nine dogs with nontransmural infarction (p less than 0.01). It is concluded that the partial sympathetic denervation produced by transmural myocardial infarction enhances the ease of induction of ventricular tachycardia and fibrillation during sympathetic stimulation. A similar mechanism may lead to increased risk for lethal arrhythmias during periods of high sympathetic tone in patients with transmural myocardial infarction.