Flow measurements via two-particle azimuthal correlations in Au + Au collisions at sqrt [s(NN)]=130 GeV

Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c.

Measurement of Lambda and Lambda(macro) particles in Au+Au collisions at the square root of S(NN) = 130 GeV

We present results on the measurement of Lambda and Lambda(macro) production in Au+Au collisions at square root of (S (NN) = 130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Lambda;/Lambda ratios are constant as a function of p(T) and the number of participants. The measured net Lambda density is significantly larger than predicted by models based on hadronic strings (e.g., HIJING) but in approximate agreement with models which include the gluon-junction mechanism.

Net charge fluctuations in Au + Au interactions at sqrt[s(NN)]=130 GeV

Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays.

Antisense oligonucleotides specific to mutated K-ras genes inhibit invasiveness of human pancreatic cancer cell lines

BACKGROUND/AIMS

Point mutations of the K-ras gene are detected in > 90% of human pancreatic cancers and may play an important role in tumorigenesis. However, correlations between mutant K-ras and the invasive activity of the tumor have remained unclarified.

METHODS

17-merphosphorothioate antisense oligonucleotides targeting K-ras point mutations were transfected into three kinds of human pancreatic cancer cell lines (MIAPaCa-2, PANC-1, and BxPC-3), and the invasive activity was investigated using an in vitro chemoinvasion assay.

RESULTS

Antisense oligonucleotides strongly inhibited the invasive activity of the cell lines with mutant K-ras genes (MIAPaCa-2, PANC-1), but not in that with a wild-type K-ras (BxPC-3).

CONCLUSION

Antisense oligonucleotides specific to mutated K-ras genes inhibited the invasiveness of human pancreatic cancer cell lines. Specific antisense therapy to the point mutation of K-ras might be a new anticancer strategy for pancreatic cancer.

Centrality dependence of pi(+/-), K(+/-), p, and (-)p production from sqrt[s(NN)] = 130 GeV Au + Au collisions at RHIC

Identified pi(+/-), K(+/-), p, and (-)p transverse momentum spectra at midrapidity in sqrt[s(NN)] = 130 GeV Au+Au collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all midrapidity particle yields per participant are found to be increasing with the number of participating nucleons. There is an indication that K(+/-), p, and (-)p yields per participant increase faster than the pi(+/-) yields. In central collisions at high transverse momenta (p(T) > or =2 GeV/c), (-)p and p yields are comparable to the pi(+/-) yields.

Transverse-mass dependence of two-pion correlations in Au+Au collisions at square root[s(NN)] = 130 GeV

Two-pion correlations in square root[s(NN)] = 130 GeV Au+Au collisions at RHIC have been measured over a broad range of pair transverse momentum k(T) by the PHENIX experiment at RHIC. The k(T) dependent transverse radii are similar to results from heavy-ion collisions at square root[s(NN)] = 4.1, 4.9, and 17.3 GeV, whereas the longitudinal radius increases monotonically with beam energy. The ratio of the outwards to sidewards transverse radii (R(out)/R(side)) is consistent with unity and independent of k(T).

Measurement of single electrons and implications for charm production in Au+Au collisions at square root[s(NN)] = 130 GeV

Transverse momentum spectra of electrons from Au+Au collisions at square root[s(NN)] = 130 GeV have been measured at midrapidity by the PHENIX experiment at the Relativistic Heavy Ion Collider. The spectra show an excess above the background from photon conversions and light hadron decays. The electron signal is consistent with that expected from semileptonic decays of charm. The yield of the electron signal dN(e)/dy for p(T) > 0.8 GeV/c is 0.025+/-0.004(stat)+/-0.010(syst) in central collisions, and the corresponding charm cross section is 380+/-60(stat)+/-200(syst) microb per binary nucleon-nucleon collision.

Suppression of hadrons with large transverse momentum in central Au+Au collisions at root square[s(NN)] = 130 GeV

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c<p(T)<5 GeV/c have been measured by the PHENIX experiment at RHIC in Au+Au collisions at root square[s(NN)] = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p+p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p+p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

Molecular characterization and regulation of the aguBA operon, responsible for agmatine utilization in Pseudomonas aeruginosa PAO1

Pseudomonas aeruginosa PAO1 utilizes agmatine as the sole carbon and nitrogen source via two reactions catalyzed successively by agmatine deiminase (encoded by aguA; also called agmatine iminohydrolase) and N-carbamoylputrescine amidohydrolase (encoded by aguB). The aguBA and adjacent aguR genes were cloned and characterized. The predicted AguB protein (M(r) 32,759; 292 amino acids) displayed sequence similarity (< or =60% identity) to enzymes of the beta-alanine synthase/nitrilase family. While the deduced AguA protein (M(r) 41,190; 368 amino acids) showed no significant similarity to any protein of known function, assignment of agmatine deiminase to AguA in this report discovered a new family of carbon-nitrogen hydrolases widely distributed in organisms ranging from bacteria to Arabidopsis. The aguR gene encoded a putative regulatory protein (M(r) 24,424; 221 amino acids) of the TetR protein family. Measurements of agmatine deiminase and N-carbamoylputrescine amidohydrolase activities indicated the induction effect of agmatine and N-carbamoylputrescine on expression of the aguBA operon. The presence of an inducible promoter for the aguBA operon in the aguR-aguB intergenic region was demonstrated by lacZ fusion experiments, and the transcription start of this promoter was localized 99 bp upstream from the initiation codon of aguB by S1 nuclease mapping. Experiments with knockout mutants of aguR established that expression of the aguBA operon became constitutive in the aguR background. Interaction of AguR overproduced in Escherichia coli with the aguBA regulatory region was demonstrated by gel retardation assays, supporting the hypothesis that AguR serves as the negative regulator of the aguBA operon, and binding of agmatine and N-carbamoylputrescine to AguR would antagonize its repressor function.

Forebrain muscarinic control of micturition reflex in rats

Functional contribution of the cholinergic pathway between the frontal cortex and basal nucleus of Meynert to micturition reflex was investigated. Male Wistar rats were subjected to bilateral lesion of the basal forebrain by ibotenic acid (IA) injection (7.5 microg/rat on each side) (BF rats). Phosphate buffered saline (PBS) was injected into control rats (sham operated rats; SO rats). Cystometrograms were obtained from conscious BF and SO rats 7-10 days after IA/PBS injection. Bladder capacity (BC) of BF rats was significantly smaller than that of SO rats (approximately 43.7%) and was accompanied by decrease in choline-acetyltransferase activity in the frontal cortices. Oxotremorine M, a muscarinic receptor agonist, increased BC in BF rats, while pirenzepine, an M1 muscarinic receptor antagonist, counteracted the effect of the oxotremorine M-induced increase in BC. Injection of oxotremorine M into the dorsal pontine tegmentum (DPT) reduced BC in BF and SO rats, while injection of pirenzepine had no effect on cystometrograms. These findings indicate that the M1 muscarinic receptor plays a part in the forebrain inhibitory mechanisms involved in the micturition reflex and that muscarinic receptor in the DPT contributes to excitatory control of micturition reflex.

Ameliorative effects of a cognitive enhancer, T-588, on place learning deficits induced by transient forebrain ischemia in rats

In the present study, we investigated the effect of (1R)-1-benzo[b]thiophen-5-yl-2-[2-(diethylamino)ethoxy]ethan-1-ol hydrochloride (T-588), a newly synthesized cognitive enhancer, on place learning deficits in rats with damage selective to the hippocampal CA1 subfield induced by transient forebrain ischemia. Three weeks after the ischemic insult, T-588 was daily administered (0.3 or 3.0 mg/kg/day po). Place learning was tested in a task in which the rat was required to alternatively visit two places located diametrically opposite each other in an open field. The ischemic rats without the treatment of T-588 displayed severe learning impairment in this task; their performance level was significantly inferior to that of the sham-operated rats. The treatment of T-588 improved dose-dependently the task performance in ischemic rats, although no apparent protective effects on ischemic damage were found histologically. These results suggested that T-588 has ameliorative effects on learning deficits induced by brain ischemia, which could be produced through enhancement of residual cognitive functions.

Measurement of the midrapidity transverse energy distribution from square root of [(s)NN] = 130 GeV Au + Au collisions at RHIC

The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at square root[s(NN)] = 130 GeV is at least epsilon(Bj) = 4.6 GeV/fm(3), which is a factor of 1.6 larger than found at sqrt[s(NN)] = 17.2 GeV ( Pb+Pb at CERN).

Rapid detection of Brevibacillus formosus BN53-1 in chicken feces

Here we describe a rapid method for detecting the hydrogen sulfide-decomposing bacterium Brevibacillus formosus BN53-1 in chicken feces. The method, which can be adapted to the specific detection of a variety of useful eubacteria, is based on blot hybridization and polymerase chain reaction (PCR), and makes use of the genus or species hypervariable region of eubacterial 16S rDNA. The approximate limit of detection under the conditions we tested was 1.0 x 10(3) cells in 10 mg of chicken feces.

Centrality dependence of charged particle multiplicity in Au-Au collisions at square root of (s)NN = 130 GeV

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Enzyme immunoassay for 6-amino-5-chloro-1-isopropyl-2-(4-methyl-1-piperazinyl)benzimidazole, a novel 5-HT3 receptor antagonist

An enzyme immunoassay (EIA) has been developed for determination of 6-amino-5-chloro-1-isopropyl-2-(4-methyl-1-piperazinyl) benzimidazole (KB-6806), a novel 5-HT3 receptor antagonist. Anti-KB-6806 antiserum was elicited against the KB-6806-bovine serum albumin (BSA) conjugate prepared by a diazo coupling reaction through the inherent 6-amino group. Beta-galactosidase-labeled 6-amino-5-chloro-1-isobutyl-2-(4-methyl-1-piperazinyl)benzimidazole was similarly prepared by diazo coupling reaction as an enzyme-labeled antigen with a hapten heterologous combination of antiserum. The modification at the 4-methyl group of the piperazine moiety of KB-6806 significantly decreased the binding affinity to the antibody. This method could quantitate KB-6806 in dog plasma in the concentration range of 0.078-10 ng/ml with good accuracy and precision. The EIA method has been successfully applied to the determination of KB-6806 in plasma after intravenous administration of KB-6806 to dogs.

Subcutaneously inoculated cells and implanted pancreatic cancer tissue show different patterns of metastases in Syrian golden hamsters

CONTEXT

We studied behavior of the subcutaneously implanted pancreatic tumors and the process of metastasis using syngeneic Syrian golden hamsters.

DESIGN

HaP-T1, a cell line derived from nitrosamine-induced pancreatic cancer in Syrian golden hamsters was used for this experiment. Thirty-five animals were divided into two groups: subcutaneous cell inoculation and subcutaneous tissue implantation. The tumor tissue was obtained from subcutaneously implanted cancer cells. One month after implantation, the tumors were resected and studied histopathologically. The animals were followed-up weekly by palpation of the peripheral lymph nodes in order to identify local recurrence. After death, necropsy was performed. Liver, lungs and pancreas specimens were taken for histopathogical study and detection of K-ras point mutation using the PCR/RFLP method.

RESULTS

The mean survival time in the subcutaneous cell inoculation group was 151+/-17.5 days, and in the subcutaneous tissue implantation group was 137 +/-12.9 days. During the follow-up, 13 subcutaneously cell inoculated hamsters (86.7%) had right axillary lymph node metastasis while subcutaneously tissue implanted hamsters did not show any palpable lymph nodes. After necropsy, 10 of the 20 subcutaneously tissue implanted animals (50%) showed metastases in the lungs at the histopathological level. However, 16 of the 20 subcutaneously tissue implanted animals (80%) showed K-ras point mutation in the lung specimens. The lungs of the animals of the subcutaneous cell inoculation group did not show any metastases. No metastases were found in the liver or the pancreas in either group.

CONCLUSION

This study suggests that homologous subcutaneous cell inoculation and subcutaneous tissue implantation models showed completely different patterns of metastasis. These models may aid further research to clarify the mechanisms of metastasis in pancreatic cancer.

[A case of Lemmel's syndrome with serious jaundice exacerbated by eating]

An 86-year old woman rapidly developed serious jaundice (T-Bil 18.3 mg/dl 12.3 mg/dl). Her jaundice was exacerbated by eating, and improved by fasting. Abdominal CT showed a giant diverticulum in the second part of the duodenum and dilation of the proximal common bile duct. Endoscopic findings confirmed juxtapapillary duodenal diverticulum in contact with the distal common bile duct. MRCP revealed extrinsic compression of the distal common bile duct by the diverticulum. Lemmel's syndrome was diagnosed. Jaundice did not recur after surgery. We speculated that in this case the diverticulum filled by duodenal contents easily compressed the distal common bile duct after eating.

Effects of aniracetam on bladder overactivity in rats with cerebral infarction

Aniracetam has been used to improve the mental condition of patients with cerebrovascular disease. Previous studies have demonstrated that aniracetam activates the residual functions of cholinergic neurons in damaged brain areas. In this study, the effects of aniracetam on bladder overactivity after left middle cerebral artery occlusion were assessed through oral or i.c.v. administration in sham-operated and cerebral infarcted rats. Oral administration of aniracetam (100 and 300 mg/kg) resulted in a significant and dose-dependent increase in bladder capacity in cerebral infarcted rats but had no effect on bladder capacity in sham-operated rats. Intracerebroventricular administration of aniracetam (0.25 and 2.5 microg/rat) resulted in a significant and dose-dependent increase in bladder capacity in cerebral infarcted rats but not in sham-operated rats. Aniracetam had no significant effect on bladder contraction pressure or micturition threshold pressure in either sham-operated or cerebral infarcted rats. Furthermore, i.c.v. administration of atropine (1 microg/rat), a muscarinic acetylcholine receptor antagonist, completely inhibited the enhancing effects of aniracetam on bladder capacity in cerebral infarcted rats. The effects of aniracetam on bladder overactivity are thought to be mediated in part by activation of cholinergic inhibitory mechanisms in the brain. These results indicate that aniracetam may improve the neurogenic voiding dysfunction observed in patients with cerebrovascular disease.