Intermediate-range chemical ordering of cations in molten RbCl-AgCl.

A first sharp diffraction peak (FSDP) is observed in the X-ray total structure factor of a molten mixture of RbCl-AgCl, while both pure melts of RbCl and AgCl do not exhibit FSDP individually. Molecular dynamics simulations were performed to investigate the origin of the FSDP with the polarizable ion model (PIM). Coexistence of covalent Ag-Cl and ionic Rb-Cl bonds leads the system to evolve intermediate range ordering, which is simulated by introducing the induced polarization in different ways between Ag-Cl with fully polarizable treatment based on Vashishta-Raman potential and Rb-Cl with suppression over-polarization in the nearest neighbor contribution based on Born-Meyer potential. The partial structure factors for both the Ag-Ag and Rb-Rb correlations, SAgAg(Q) and SRbRb(Q), show a positive contribution to the FSDP, while SAgRb(Q) for the Ag-Rb correlation exhibits a negative contribution, indicating that Ag and Rb ions are distributed in an alternating manner within the intermediate-range length scale. The origin of the intermediate-range chemical ordering of cations can be ascribed to the preferred direction of the dipole moments of anions in the PIM.

Extracellular volume fraction using contrast-enhanced CT is useful in differentiating intrahepatic cholangiocellular carcinoma from hepatocellular carcinoma.

Objectives: To evaluate whether tumor extracellular volume fraction (fECV) on contrast-enhanced computed tomography (CT) aids in the differentiation between intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC). Methods: In this retrospective study, 113 patients with pathologically confirmed ICC (n = 39) or HCC (n = 74) who had undergone preoperative contrast-enhanced CT were enrolled. Enhancement values of the tumor (Etumor) and aorta (Eaorta) were obtained in the precontrast and equilibrium phase CT images. fECV was calculated using the following equation: fECV [%] = Etumor/Eaorta × (100 - hematocrit [%]). fECV values were compared between the ICC and HCC groups using Welch's t-test. The diagnostic performance of fECV for differentiating ICC and HCC was assessed using receiver-operating characteristic (ROC) analysis. fECV and the CT imaging features of tumors were evaluated by two radiologists. Multivariate logistic regression analysis was performed to identify factors predicting a diagnosis of ICC. Results: Mean fECV was significantly higher in ICCs (43.8% ± 13.2%) than that in HCCs (31.6% ± 9.0%, p < 0.001). The area under the curve for differentiating ICC from HCC was 0.763 when the cutoff value of fECV was 41.5%. The multivariate analysis identified fECV (unit OR: 1.10; 95% CI: 1.01-1.21; p < 0.05), peripheral rim enhancement during the arterial phase (OR: 17.0; 95% CI: 1.29-225; p < 0.05), and absence of washout pattern (OR: 235; 95% CI: 14.03-3933; p < 0.001) as independent CT features for differentiating between the two tumor types. Conclusions: A high value of fECV, peripheral rim enhancement during the arterial phase, and absence of washout pattern were independent factors in the differentiation of ICC from HCC.

Anatomical evaluation of facial nerve pathways and dissection of "premasseter space" for rhytidectomy in Asians.

BACKGROUND: Partial detachment of the superficial musculoaponeurotic system (SMAS) by dissection of the premasseter space (PMS) is an option for enhancing the effectiveness of SMAS-based rhytidectomy. The aim of this study was to identify the underlying cause of the potential risk of motor nerve impairment sometimes caused by PMS dissection and to consider the effective use of PMS dissection, especially in Asians. METHODS: Detailed dissection was carried out on six fixed Japanese cadavers to evaluate facial nerve pathways around the PMS. RESULTS: The anterior wall of the PMS was opaque because each face exhibited fibers of various thicknesses within and around the anterior border of the masseter. The ascending ramifications of the buccal trunk ran through the fibers, outside the anterior border of the masseter in some faces but within it in others. CONCLUSIONS: This study revealed the presence of a danger zone when dissecting the PMS in Asians. Severing the fibers that fix the SMAS to the masseter fascia around the anterior border of the masseter is sometimes unavoidable to attain good mobility of the SMAS. Surgeons must be mindful of the fibers near the anterior border of the masseter because they may be outside the PMS and contain buccal trunk ramifications; the anterior wall of the PMS tends to be opaque in Asians. Nonetheless, the extent of PMS dissection should be determined on an individual basis. The present findings may help to reduce relevant risks in Asian patients and standardize procedures for effective rhytidectomy. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the table of contents or the online instructions to authors at www.springer.com/00266.

Disturbed CD4+ T cell homeostasis and in vitro HIV-1 susceptibility in transgenic mice expressing T cell line-tropic HIV-1 receptors.

T cell line-tropic (T-tropic) HIV type 1 strains enter cells by interacting with the cell-surface molecules CD4 and CXCR4. We have generated transgenic mice predominantly expressing human CD4 and CXCR4 on their CD4-positive T lymphocytes (CD4+ T cells). Their primary thymocytes are susceptible to T-tropic but not to macrophage-tropic HIV-1 infection in vitro, albeit with a viral antigen production less efficient than human peripheral blood mononuclear cells. Interestingly, even without HIV infection, transgenic mice display a CD4+ T cell depletion profile of peripheral blood reminiscent of that seen in AIDS patients. We demonstrate that CD4+ T cell trafficking in transgenic mice is biased toward bone marrow essentially due to CXCR4 overexpression, resulting in the severe loss of CD4+ T cells from circulating blood. Our data suggest that CXCR4 plays an important role in lymphocyte trafficking through tissues, especially between peripheral blood and bone marrow, participating in the regulation of lymphocyte homeostasis in these compartments. Based on these findings, we propose a hypothetical model in which the dual function of CXCR4 in HIV-1 infection and in lymphocyte trafficking may cooperatively induce progressive HIV-1 infection and CD4+ T cell decline in patients.

Diversity in the signals required for nuclear accumulation of U snRNPs and variety in the pathways of nuclear transport.

The requirements for nuclear targeting of a number of U snRNAs have been studied by analyzing the behavior of in vitro-generated transcripts after microinjection into the cytoplasm of Xenopus oocytes. Like the previously studied U1 snRNA, U2 snRNA is excluded from the nucleus when it does not have the 2,2,7mGpppN cap structure typical of the RNA polymerase II (pol II)-transcribed U snRNAs. Surprisingly, two other pol II-transcribed U snRNAs, U4 and U5, have a much less stringent requirement for the trimethyl cap structure. The gamma-monomethyl triphosphate cap structure of the RNA polymerase III-transcribed U6 snRNA, on the other hand, is shown not to play a role in nuclear targeting. Wheat germ agglutinin, which is known to prevent the import of many proteins into the nucleus, inhibits nuclear uptake of U6, but not of U1 or U5 snRNAs. Conversely, a 2,2,7mGpppG dinucleotide analogue of the trimethyl cap structure inhibits transport of the pol II U snRNAs, but does not detectably affect the transport of either U6 snRNA or a karyophilic protein. From these results it can be deduced that U6 enters the nucleus by a pathway similar or identical to that used by karyophilic proteins. The composite nuclear localization signals of the trimethyl cap-containing U snRNPs, however, do not function in the same way as previously defined nuclear targeting signals.

Petrous apex cholesterol granuloma treated via the endoscopic transsphenoidal approach.

Numerous surgical approaches have been used to treat petrous apex cholesterol granulomas. They are usually treated via the transtemporal- or middle fossa approach; some are managed endoscopically. We present a patient treated by the endoscopic transsphenoidal approach and review the literature.

Functional domains of rep2, a transcriptional activator subunit for Res2-Cdc10, controlling the cell cycle "start".

In the fission yeast Schizosaccharomyces pombe, passage from G1 to S-phase requires the execution of the transcriptional factor complex that consists of the Cdc10 and Res1/2 molecules. This complex activates the MluI cell cycle box cis-element contained in genes essential for S-phase onset and progression. The rep2(+) gene, isolated as a multicopy suppressor of a temperature-sensitive cdc10 mutant, has been postulated to encode a putative transcriptional activator subunit for the Res2-Cdc10 complex. To identify the rep2(+) function and molecularly define its domain organization, we reconstituted the Res2-Cdc10 complex-dependent transcriptional activation in Saccharomyces cerevisiae. Reconstitution experiments, deletion analyses using one and two hybrid systems, and in vivo Res2 coimmunoprecipitation assays show that the Res2-Cdc10 complex itself can recognize but cannot activate MluI cell cycle box without Rep2, and that consistent with its postulated function, Rep2 contains 45-amino acid Res2 binding and 22-amino acid transcriptional activation domains in the middle and C terminus of the molecule, respectively. The functional essentiality of these domains is also demonstrated by their requirement for rescue of the cold-sensitive rep2 deletion mutant of fission yeast.

Potassium channel blocker activates extracellular signal-regulated kinases through Pyk2 and epidermal growth factor receptor in rat cardiomyocytes.

OBJECTIVES: We sought to determine whether potassium (K(+)) channel blockers (KBs) can activate extracellular signal-regulated kinase (ERK) and to characterize the upstream signals leading to ERK activation in cardiomyocytes. BACKGROUND: Because KBs attenuate K(+) outward current, they may possibly prolong the duration of action potentials, leading to an increase in calcium (Ca(2+)) transient ([Ca(2+)](i)) in cardiomyocytes. Elevation of intracellular Ca(2+) levels can trigger various signaling events. Influx of Ca(2+) through L-type Ca(2+) channels after membrane depolarization induced activation of MEK and ERK through activation of Ras in neurons. Although KBs are frequently used to treat cardiac arrhythmias, their effect on signaling pathways remains unknown. METHODS: Primary cultured rat cardiomyocytes were stimulated with four different KBs-4-aminopyridine (4-AP), E-4031, tetra-ethylammonium and quinidine-and phosphorylation of ERK, proline-rich tyrosine kinase 2 (Pyk2) and epidermal growth factor receptor (EGFR) was detected. Action potentials were recorded by use of a conventional microelectrode. (Ca(2+))(i) was monitored by the fluorescent calcium indicator Fluo-4. RESULTS: E-4031, 4-AP, tetra-ethylammonium and quinidine induced phosphorylation of ERK. 4-Aminopyridine prolonged the duration of action potentials by 37% and increased (Ca(2+))(i) by 52% at 1 mmol/l. Pre-incubation of ethyleneglycoltetraacetic acid, 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis and diltiazem completely blocked this phosphorylation, whereas flufenamic acid and benzamil did not. 4-Aminopyridine induced tyrosine phosphorylation of Pyk2 and EGFR, which peaked at 5 and 10 min, respectively. Cytochalasin D, AG1478 and dominant-negative EGFR strongly inhibited the phosphorylation of ERK, whereas calphostin C, calmidazolium and KN62 did not. CONCLUSIONS: These findings indicate that KBs induce ERK activation, which starts with Ca(2+) entry through the L-type Ca(2+) channel in cardiomyocytes, and that EGFR and Pyk2 are involved in this activation.

Cytochemical and molecular biological aspects of the pituitary and pituitary adenomas--cell differentiation and transcription factors.

The anterior pituitary is composed of several cell types, each responsible for the production of specific hormones. Each hormone secreting cells is defined by the activation of its respective hormone genes in a temporally and spatially regulated manner. Recent development in cytochemistry and molecular biology have provided various aspects of human pituitary adenomas, i.e., functional differentiation and classification. The molecular factors that determine hormone production have now been identified as transcription factors. Many novel transcription factors that play a role in anterior pituitary development are implicated. In this review, we focus on the transcriptional factors roles on functional differentiation of the pituitary cells and adenomas and the contribution of cytochemistry and recent development in molecular biological techniques.

Retarding effect of dietary restriction on the accumulation of 8-hydroxy-2'-deoxyguanosine in organs of Fischer 344 rats during aging.

An age-related accumulation in rats of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, and the effect of dietary restriction on the accumulation of 8-OHdG were examined. The 8-OHdG concentrations of nuclear DNA in organs of ad libitum fed rats were similar in young and middle age, but increased significantly in kidney at 24 months of age, in heart and liver at 27 months of age, and in brain at 30 months of age. The 8-OHdG concentration in dietary-restricted rats showed no changes in any organ up to 30 months of age and then was increased at 33 months of age. Dietary restriction retarded the onset of the age-related increase in 8-OHdG concentration, although it did not reduce the concentration in young and middle age. These results suggest that the effect of dietary restriction on the extension of life-span in rats might be related to a reduction in oxidative damage.

Factors responsible for inhibiting the motility of zoospores of the phytopathogenic fungus Aphanomyces cochlioides isolated from the non-host plant Portulaca oleracea.

In a survey of plant secondary metabolites regulating the behaviour of Aphanomyces cochlioides zoospores, we found that root extracts of Portulaca oleracea inhibited zoospore motility. Bioassay-directed fractionation of Portulaca constituents revealed that the inhibitory activity was dependent on the interaction of two chemically different factors. These were identified as a phenolic compound, N-trans-feruloyltyramine, which by itself was active as a zoospore stimulant, and an acidic compound, 1-linoleoyl-2-lysophosphatidic acid monomethyl ester, which had zoospore-repellent activity. When Chromosorb W AW particles coated with a mixture of these pure compounds were bioassayed in Petri dishes, the inhibitory effect on zoospore motility was identical with that caused by root tip or root extracts of P. oleracea. Inhibited zoospores rapidly settled to the bottom of the Petri dishes where they initially encysted, and then germinated within 1-2 h. This is the first report of factors which inhibit zoospore motility without killing or bursting the zoospores.

The effect of exercise training on oxidative damage of lipids, proteins, and DNA in rat skeletal muscle: evidence for beneficial outcomes.

Moderate daily exercise is known to be beneficial to health, reducing risks of a number of age-related disorders. Molecular mechanisms that bring about these effects are not clear. In contrast, it has been claimed that some types of prolonged physical exertion are detrimental to health because active oxygen species are generated excessively by enhanced oxygen consumption. Using two age groups of rats, young (4 week) and middle aged (14 months), we investigated the effects of long-term swimming training on the oxidative status of phospholipids, proteins, and DNA. The concentration of thiobarbituric acid reactive substances and 4-hydroxynonenal protein adducts did not differ in the gastrocnemius muscle between exercised and nonexercised animals in the two age groups. The extent of carbonylation in a protein of molecular weight around 29 KDa and the amount of 8-hydroxydeoxyguanosine in nuclear DNA were smaller (p<.05) in the exercised rats than in the sedentary animals. Activities of DT-diaphorase (C1: 29.3+/-1.9; C2: 36.1+/-2.6; E1: 27.2+/-1.3; C2: 33.4+/-2.9 nmol/mg protein) and proteasome, a major proteolytic enzyme for oxidatively modified proteins were significantly higher in the exercised animals of both age groups (p<.05). The adaptive response against oxidative stress induced by moderate endurance exercise constitutes a beneficial effect of exercise.

Age-related changes in oxidative damage to lipids and DNA in rat skin.

Skin is a tissue exposed most frequently to oxidative stress from the environment in daily life. Age-related changes of oxidative damage and antioxidant enzyme activity in the skin were examined in male Fischer 344 rats aged 6 to 30 months. The contents of phosphatidylcholine hydroperoxide (PCOOH) and thiobarbituric acid-reacting substances (TBARS) increased linearly with age. The content of cholesterol hydroperoxide increased until 24 months of age and then decreased. The content of 8-oxo-2'-deoxyguanosine (8-oxodG) increased gradually with age, and was significantly higher at 30 months of age than at 6 months of age. Superoxide dismutase activity tended to decrease with age. The activities of catalase and glutathione peroxidase showed no changes with age. We examined the effect of dietary restriction on the accumulation of oxidative damage in rat skin. The increase in PCOOH content in the skin of dietary-restricted rats was suppressed until 30 months of age. The TBARS and cholesterol hydroperoxide contents in the skin of dietary-restricted rats were significantly lower than in the skin of ad libitum-fed rats, while the 8-oxodG content was somewhat lower in the dietary-restricted rats than the ad libitum-fed rats. These results indicate that oxidative damage to the lipids and DNA in rat skin increases with age and that dietary restriction delays the accumulation of oxidative damage in skin.

Contributions of immunohistochemistry and in situ hybridization to the functional analysis of pituitary adenomas.

Immunohistochemistry (IHC) and recently in situ hybridization (ISH) have elucidated various aspects of human pituitary adenomas, i.e., functional differentiation and classification, transcription factors and mechanism of hormone production, regulation of hormone secretion, and processing of prohormones. Recently, the use of tyramide (catalyzed signal amplification; TSA or CSA) and RT-PCR has been effective for detection of trivial amount of proteins (peptides) and mRNA, respectively. Immunomolecular histochemistry is expected to further clarify the function and biology of human pituitary adenomas.

Single bout of exercise eliminates the immobilization-induced oxidative stress in rat brain.

We were interested in the effects of immobilization (IM), a single bout of exercise (E) and immobilization followed by exercise (EIM) on memory and oxidative damage of macromolecules in hippocampus of rat brain. Eight hours of IM resulted in impairment of passive avoidance test (memory retrieval deficit) and increased latency to start locomotion in an open-field test. Two hours of swimming did not significantly alter the memory retrieval deficit and latency, while the EIM group had longer latency and similar memory than control and E groups. The oxidative damage of lipids, proteins and nuclear DNA increased significantly in IM group and no increase was observed in E and EIM animals. The activity of proteasome was not altered in any groups. The activity of glutamine synthetase (GS) was decreased in IM group (P < 0.05), this down regulation was not observed in E and EIM groups. These data suggest that oxidative damage of macromolecules is associated with impaired cognitive function. Single bout of exercise after immobilization eliminates the oxidative damage of macromolecules and normalizes memory function, probably by its ability to restore the activity level of GS and eliminate the consequences of immobilization-induced prolonged efflux of glutamate.

Regular exercise improves cognitive function and decreases oxidative damage in rat brain.

The biochemical mechanisms by which regular exercise significantly benefits health and well being, including improved cognitive function, are not well understood. Four-week-old (young) and 14-month-old (middle aged) Wistar rats were randomly assigned to young control and young exercised, middle-aged control and middle-aged exercised groups. Exercise groups were exposed to a swimming regime of 1 h a day, 5 days a week for 9 weeks. The passive avoidance test showed that middle-aged exercised rats had significantly (P<0.05) better short- (24 h) and long-term (72 h) memory than aged-matched control rats. Conditioned pole-jumping avoidance learning was improved markedly in both age groups by exercise. Brain thiobarbituric acid-reactive substances and 8-hydroxy-2'deoxyguanosine content in the DNA did not change significantly, while the protein carbonyl levels decreased significantly (P<0.05) in both exercised groups. This decrease was accompanied by an increase in the chymotrypsin-like activity of proteasome complex in the exercised groups, whereas trypsin-like activity did not differ significantly between all groups. The DT-diaphorase activity increased significantly (P<0.05) in the brain of young exercised animals. These data show that swimming training improves some cognitive functions in rats, with parallel attenuation of the accumulation of oxidatively damaged proteins.

The coupling valve graft: a procedure for double-valve replacement.

Coupling valve grafting, a procedure to enlarge the annulus of the aortic valve and of the mitral valve simultaneously, is described. It consists of extending the J-shaped aortotomy through the middle of the noncoronary cusp into the superior aspect of the left atrium and down the anterior leaflet of the mitral valve. Then the mitral and aortic valves are replaced with a coupling valve graft, a vascular prosthesis attached to two prosthetic valves. This technique seems to be most suitable for patients in whom the valves of both annuli are narrow, as is often seen in aortic and mitral stenosis. Since both valve annuli can be enlarged greatly in this procedure, combinations of prosthetic valve sizes can be freely chosen for the two valves.

Effect of green tea catechins on the amount of 8-hydroxydeoxyguanosine (8-OHdG) in pancreatic and hepatic DNA after a single administration of N-nitrosobis(2-oxopropyl)amine (BOP).

Effects of green tea catechins on N-nitrosobis(2-oxopropyl)amine (BOP)-induced oxidative stress in pancreas and liver were examined. Hamsters were divided into two groups: one group was given free access to a 0.1% solution of green tea catechins as drinking water (c-ham) and the other to plain tap water (w-ham) for 1 week before subcutaneous injection of BOP 20 mg/kg body weight. Zero, 1, 2, 6, 12, 24, and 48 h after BOP injection, the pancreas and liver were excised and the tissue concentration of lipid peroxides (TBA values) and the amount of 8-hydroxydeoxyguanosine (8-OHdG) in nuclear DNA were measured. The concentration of lipid peroxides and the amount of 8-OHdG in the pancreas showed similar patterns of change between c- and w-ham. Soon after BOP injection, the concentration of lipid peroxides and the amount of 8-OHdG increased with a peak at 1 and 6 h, respectively. Their peak values of c-ham were significantly depressed compared with those of w-ham. Both levels returned to steady-state levels by 24 h. In the liver, the concentration of lipid peroxides and the amount of 8-OHdG were not affected by BOP administration. These results suggest that BOP induces oxidative damages in the target organ and oral intake of green tea catechins has a protective effect on the oxidative stress.

Dihydroflavonols from Lannea coromandelica.

The dihydroflavonols, (2R,3S)-(+)-3',5-dihydroxy-4',7-dimethoxydihydroflavonol and (2R,3R)-(+)-4',5,7-trimethoxydihydroflavonol were isolated from the stem bark of Lannea coromandelica, along with the known (2R,3R)-(+)-4',7-di-O-methyldihydroquercetin, (2R,3R)-(+)-4',7-di-O-methyldihydrokaempferol and (2R,3R)-(+)-4'-O-methyldihydroquercetin. All five compounds were isolated for the first time from the genus Lannea; furthermore, (2R,3S)-(+)-3',5-dihydroxy-4',7-dimethoxydihydroflavonol, was a rare cis-type isomer. The structures of all compounds were elucidated by spectroscopic methods including 2D NMR and CD analysis.