On the Importance of Exposure Variability to the Doses of Volatile Organic Compounds

The connection between occupational exposure to volatile organic compounds (VOCs) and the resulting internal doses is complicated by variability in air levels from day to day and by nonlinear kinetics of metabolism. We investigated long-term liver doses of VOCs and their metabolites using a physiologically based toxicokinetic model, to which 10,000 random 8-h exposures were inputted. Three carcinogenic VOCs were studied (i.e., benzene, perchloroethylene, and acrylonitrile); these compounds are all bioactivated in the liver and represent a wide range of an important toxicokinetic parameter Vmax/QL x KM. For each VOC, simulations were performed using mean air concentrations (muX) between 0.0003 and 1 mg/l (which covers both linear and saturated metabolism) and using coefficients of variation of exposure (CVX) between 0.23 and 2.18 (which includes most occupational settings). Two long-term measures of internal dose were examined, i.e., the area under the liver concentration-time curve (AUCL) and the area under the metabolic rate-time curve (AURC). Interestingly, both AUCL and AURC were linear functions of cumulative exposure (CE, mg x h/l air) even when metabolism was saturated and CVX was large. Yet, at a given CE, both AUCL and AURC were affected by CVX, with the magnitude of the effect increasing with Vmax/QL x KM (i.e., perchloroethylene < benzene < acrylonitrile). Nonetheless, the effects of CVX were typically only a few percent and should be of little consequence unless a VOC has large values of Vmax/QL x KM, muX,and CVX. We conclude that CE should be a sufficient predictor of the dose of either the parent chemical (VOC) or its metabolite in the liver, even when metabolism is nonlinear. We also observed that AUCL and AURC were sensitive to changes in values of model parameters in the high-variability scenarios, suggesting that (when CVX is large) the population variability of AUCL and AURC can be quite large at a fixed CE.

Molecular sieving MFI-type zeolite membranes for pervaporation separation of xylene isomers

Molecular sieving MFI-type zeolite membranes were prepared by a secondary growth method without using an organic template. Silicalite membranes with intercrystalline pores minimized or eliminated were obtained by this synthesis method which avoids the template removal step. The silicalite membrane exhibits molecular sieving characteristics with pervaporation separation factor for p-xylene to o-xylene or m-xylene of as high as about 70, the highest ever reported for a pervaporation membrane.

Antibody-mediated endothelial cell damage via nitric oxide

Vascular disorders, resulting from endothelial cell dysfunction, may be caused by various stimuli, including infectious pathogens, cytotoxic reagents, and pathophysiological mechanisms mediated by immune responses. Endothelial cell dysfunction characterized by apoptosis and abnormal immune activation is, at least in part, induced by anti-endothelial cell antibody (AECA) in some cases of autoimmune disease. However, the molecular mechanisms of AECA-mediated pathogenetic damage to host vascular system remain unclear. The dual role of nitric oxide (NO) both in endothelial cell apoptosis and survival has been described. In this paper, endothelial cell apoptosis caused by the presence of cross-reactive AECA via a NO-mediated mechanism is demonstrated in dengue virus infection. Endothelial cells undergo apoptosis via the mitochondria-dependent pathway that is regulated by NO production. NO-regulated endothelial cell injury thus may play a role in the disruption of vessel endothelium and contribute to the AECA-induced pathogenesis of vasculopathy. The modulation of NO may provide the therapeutic strategies for autoimmune diseases by preventing the AECA-mediated endothelial cell damage.

Combined removal of SO2 and NO using sol-gel-derived copper oxide coated alumina sorbents/catalysts

The present paper reports experimental results on the removal of sulfur dioxide and nitrogen oxide from simulated flue gas using a copper oxide coated on alumina sorbent/catalyst prepared by the sol-gel method. Selective catalytic reduction of nitric oxide by ammonia over sol-gel derived CuO/gamma-Al2O3 sorbents/catalysts with different degrees of sulfation was studied in a fixed-bed packed reactor. The optimum temperature for NO reduction was found at 350 degrees C for both fresh and sulfated catalysts. The properties for simultaneous removal of SO2 and NO by the sol-gel-derived CuO/gamma-Al2O3 sorbents were studied using simulated dry flue gas. The optimum operating temperature for the combined deSO2/deNO operations was identified at 350 degrees C. At the space velocity of 5200 h(-1) and 350 degrees C, a fixed-bed reactor packed with the 7.9 wt% CuO/gamma-Al2O3 sorbent prepared by the sol-gel method offers SO2 sorption capacity of 2.3 mmol g(-1) and NO conversion of 92% with a dry simulated flue gas as the feed. Under these experimental conditions, the sol-gel derived sorbents/catalysts have comparable efficiency for removal of SO2 and NOx as their commercial counterparts. The significantly higher crush strength of the sol-gel derived sorbents/catalysts make them very promising for their use in the copper oxide process for combined removal of SO2 and NOx from flue gas in a single unit operation.

Mechanism of high-temperature CO2 sorption on lithium zirconate

Lithium zirconate (Li2ZrO3) is one of the most promising materials for CO2 separation from flue gas at high temperature. This material is known to be able to absorb a large amount of CO2 at around 400-700 degrees C. However, the mechanism of the CO2 sorption/desorption process on Li2ZrO3 is not known yet. In this study, we examined the CO2 sorption/desorption mechanism on Li2ZrO3 by analyzing the phase and microstructure change of Li2ZrO3 during the CO2 sorption/desorption process with the help of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) analyses. Li2ZrO3 powders were prepared from lithium carbonate (Li2CO3) and zirconium oxide (ZrO2) by the solid-state method, and the CO2 sorption/desorption property was examined by TGA. It was shown that pure Li2ZrO3 absorbs a large amount of CO2 at high temperature with a slow sorption rate. Addition of potassium carbonate (K2CO3) and Li2CO3 in the Li2ZrO3 remarkably improves the CO2 sorption rate of the Li2ZrO3 materials. DSC analysis for the CO2 sorption process indicates that doped lithium/potassium carbonate is in the liquid state during the CO2 sorption process and plays an important role in improving the CO2 uptake rate. XRD analysis for phase and structure change during the sorption/desorption process shows that the reaction between Li2ZrO3 and CO2 is reversible. Considering all data obtained in this study, we proposed a double-shell model to describe the mechanism of the CO2 sorption/desorption on both pure and modified Li2ZrO3.

Use of polymerase chain reaction to detect the soft rot pathogen, Pythium myriotylum, in infected ginger rhizomes

AIMS

The aims are to establish a polymerase chain reaction (PCR)-based method for detecting Pythium myriotylum in the rhizome of ginger and diagnosing ginger soft rot and screening health seed ginger.

METHODS AND RESULTS

A booster PCR method was established for detection of P. myriotylum using a specific primer selected from rDNA ITS1 region coupled with universal primer ITS2. It successfully applied to the detection of P. myriotylum in naturally infected ginger rhizomes but not from DNA of ginger rhizomes collected from field without target fungus.

CONCLUSIONS

A specific method for detecting P. myriotylum was achieved.

SIGNIFICANCE AND IMPACT OF THE STUDY

The new PCR method has allowed us to monitor ginger for the presence of P. myriotylum as a way of disease diagnosis or healthy seed ginger examination.

The effect of dexamethasone upon patient-controlled analgesia-related nausea and vomiting

Ninety female patients were enrolled in this randomised, double-blind, placebo-controlled study to compare the anti-emetic effect of intravenous dexamethasone 8 mg with saline control in preventing patient-controlled analgesia-related nausea and vomiting following major orthopaedic surgery. The prophylactic administration of dexamethasone 8 mg significantly reduced the overall incidence of patient-controlled analgesia-related nausea and vomiting (p<0.001) and the need for rescue anti-emetics (p<0.01). Furthermore, patients who received dexamethasone showed a higher incidence of complete responses (no vomiting or need for rescue anti-emetic for a 24-h postoperative period) than those who received saline (p<0.05). We conclude that dexamethasone 8 mg may be valuable for preventing patient-controlled analgesia-related nausea and vomiting in women undergoing major orthopaedic surgery.

In-vivo phenotyping for CYP3A by a single-point determination of midazolam plasma concentration

We investigated whether a single plasma midazolam concentration could serve as an accurate predictor of total midazolam clearance, an established in-vivo probe measure of cytochrome P450 3A (CYP3A) activity. In a retrospective analysis of data from 224 healthy volunteers, non-compartmental pharmacokinetic parameters were estimated from plasma concentration-time curves following intravenous (IV) and/or oral administration. Based on statistical moment theory, the concentration at the mean residence time (MRT) should be the best predictor of the total area under the curve (AUC). Following IV or oral midazolam administration, the average MRT was found to be approximately 3.5 h, suggesting that the optimal single sampling time to predict AUC was between 3 and 4 h. Since a 4-h data point was common to all studies incorporated into this analysis, we selected this time point for further investigation. The concentrations of midazolam measured 4 h after an IV or oral dose explained 80 and 91% of the constitutive interindividual variability in midazolam AUC, respectively. The 4-h midazolam measurement was also an excellent predictor of drug-drug interactions involving CYP3A induction and inhibition. Compared with baseline values, the direction and magnitude of change in midazolam AUC and the 4-h concentration were completely concordant for all study subjects. We conclude that a single 4-h midazolam concentration following IV or oral administration represents an accurate marker of CYP3A phenotype under constitutive and modified states. Moreover, the single-point approach offers an efficient means to phenotype and identify individuals with important genetic polymorphisms that affect CYP3A activity.

Prevention of PONV with dexamethasone in female patients undergoing desflurane anesthesia for thyroidectomy

BACKGROUND

Desflurane is associated with a higher incidence of 24-h postoperative nausea and vomiting (PONV) as compared with sevoflurane or isoflurane. Dexamethasone 5 mg i.v. is suggested to be the minimum effective dose for prophylaxis of PONV in women undergoing thyroidectomy with isoflurane anesthesia. The objective of this study was to investigate whether a 5 mg dose of dexamethasone could be enough for, or a larger dose at 8 mg, could be more capable of preventing PONV in women undergoing desflurane anesthesia for thyroidectomy.

METHODS

One hundred and thirty five patients were assigned to receive one of three treatment regimens prior to induction i.e., dexamethasone 8 mg i.v. (Group D8), dexamethesone 5 mg i.v. (Group D5) or saline (Group S).

RESULTS

It was demonstrated that the prophylactic administration of either dexamethasone 8 mg or 5 mg significantly reduced the overall incidence of PONV in patients undergoing thyroidectomy with desflurane anesthesia (P < 0.001, Group D8 vs. Group S; Group D5 vs. Group S). However, patients who received dexamethasone 8 mg showed a higher incidence of complete responses (no vomiting or need of rescue antiemetic medication for a 24-h postoperative period) in comparison with those receiving dexamethasone 5 mg (86% vs. 67%; P < 0.01).

CONCLUSIONS

The results of this study showed that in PONV prophylaxis, in female patients undergoing desflurane anesthesia for thyroidectomy, the effect of dexamethasone 8 mg was superior to that of dexamethasone 5 mg.

Antiproliferative effect of nitric oxide on rat glomerular mesangial cells via inhibition of mitogen-activated protein kinase

The effect of nitric oxide (NO) donors and lipopolysaccharide (LPS) on the proliferation of rat glomerular mesangial cells was characterized. Exogenous application of a NO donor inhibited serum-induced proliferation in a time- and dose-dependent manner. S-Nitrosoglutathione (GSNO) also increased cGMP generation and arachidonic acid release, but it did not cause any measurable increase in the cytosolic Ca2+ concentration. Chelation of cytosolic Ca2+ or inhibition of mitogen-activated protein kinase (MAPK) kinase had an inhibitory effect on proliferation, but neither enhanced the antiproliferative effect of GSNO. In contrast, inhibition of guanylate cyclase or phospholipase A2 had no effect on proliferation, but partially reversed GSNO-induced antiproliferation by approximately 98 and 65%, respectively. GSNO did not cause cell death. Incubation of cells with LPS induced endogenous NO generation and had an antiproliferative effect. LPS-induced antiproliferation was reversed completely by inhibition of nitric oxide synthase and partially by inhibition of guanylate cyclase or phospholipase A2. GSNO or LPS inhibited serum-induced MAPK activation, and both effects were partially reversed by inhibition of guanylate cyclase or phospholipase A2. Inclusion of 8-bromo-cGMP or arachidonic acid in the growth medium resulted in a similar antiproliferative effect. In conclusion, in rat glomerular mesangial cells, MAPK inhibition and an antiproliferative effect could be induced by either an increase in the cellular concentration of NO or exposure of the cells to LPS. Part of the effect of NO was attributable to the increased cellular cGMP generation and arachidonic acid release.

New phenanthridine linkers for the solid-phase synthesis of acid-containing compounds

Two novel, reusable phenanthridine linkers that use cerium ammonium nitrate as a cleavage reagent are described. These linkers are based on a disubstituted amide and are designed for the release of carboxylic acids but tolerate exposure to acidic, basic, and reductive reaction conditions. Application of these linkers to solid-phase organic synthesis affords products in excellent yields and high purities.

Facile allylic C-H bond activation on the bridging disulfide ligand in the Ru(III) dinuclear complex having a conjugated RuSSRu core

Treatment of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)(mu-S(2))](CF(3)SO(3))(4) (1), which is prepared by the reaction of [[RuCl(P(OCH(3))(3))(2)](2)(mu-S(2))(mu-Cl)(2)] (2) with 4 equiv of AgCF(3)SO(3), with terminal alkenes such as 1-pentene, allyl ethyl ether, allyl phenyl ether, 1,4-hexadiene, and 3-methyl-1-butene, resulted in the formation of complexes carrying a C(3)S(2) five-membered ring, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)CH(2)CR(1)R(2)S]](CF(3)SO(3))(4) (3, R(1) = CH(2)CH(3), R(2) = H, 40%; 4, R(1) = OCH(2)CH(3), R(2) = H, 60%; 5, R(1) = OC(6)H(5), R(2) = H, 73%; 6, R(1) = CH=CHCH(3), R(2) = H, 48%; 7, R(1) = R(2) = CH(3), 40%). Reaction of 1 with methylenecycloalkanes was found to give several different types of products, depending on the ring size of the substrates. A trace of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(CH(2)CH(2))CH(CH(3))S]](CF(3)SO(3))(4) (9) having a C(2)S(2) four-membered ring to bridge the two Ru atoms was obtained by the reaction of 1 with methylenecyclobutane, whereas the reaction with methylenecyclohexane gave [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-S(CH(2)(C=CHCH(2)CH(2)CH(2)CH(2))S)](CF(3)SO(3))(3) (10) in 69% yield via C-S bond formation and elimination of a proton. Throughout these reactions with alkenes giving a variety of products, the activation of the allylic C-H bond is always the essential and initial key step.

Different risks of symptomatic brain necrosis in NPC patients treated with different altered fractionated radiotherapy techniques

PURPOSE

To report our observation of excessive temporal lobe necrosis in nasopharyngeal carcinoma (NPC) patients treated with 160 cGy b.i.d. radiotherapy technique. During the same period, patients treated with 120 cGy b.i.d. have not shown a similar tendency. Our experience may be useful for designing unconventional radiotherapy regimens for NPC patients.

METHODS AND MATERIALS

During the period from October 1991 to January 1998, 81 M0, previously untreated NPC patients completed altered fractionated radiotherapy. Seventy patients were treated with the hyperfractionated technique, and 11 were treated using the accelerated-hyperfractionated scheme. Hyperfractionated radiotherapy was delivered using 120 cGy b.i.d. separated by 6-h intervals throughout the course. A minimum tumor dose of 8000 cGy was the standard dose over an 8-week period. With the accelerated-hyperfractionated scheme, 160 cGy was given twice daily, also with an interval of 6 h. The minimum tumor dose ranged between 6840 and 7640 cGy, with 7 of the 11 patients receiving 7000 cGy. The arrangement of portals was the same for both regimens. The follow-up period for patients alive was from 32 to 102 months with a median of 61 months for the hyperfractionated patients. For the accelerated-hyperfractionated group, it ranged from 67 to 82 months with a median of 72 months. No patient was lost to follow-up.

RESULTS

At the time of analysis, 49 of the 70 patients in the hyperfractionated group were alive. In the accelerated group, 8 of the 11 patients were alive. The estimated radiation dose to the temporal lobe for the hyperfractionated group was 6000-7440 cGy with a median of 7080 cGy. For the accelerated-hyperfractionated group, the dose range was 4480-6700 cGy with a median of 6400 cGy. Of the 70 patients treated with hyperfractionated radiotherapy, none developed symptomatic brain necrosis, despite the higher total dose to the temporal lobe in general. In contrast, 3 of the 11 (27%) patients irradiated using the accelerated-hyperfractionated regimen suffered from temporal lobe necrosis at 16, 19, and 40 months after completion of radiotherapy.

CONCLUSION

An excessive incidence of temporal lobe necrosis was noted when an accelerated-hyperfractionated regimen with 160 cGy b.i.d. was used in NPC patients with a median brain dose of 6400 cGy. There has been no such event in patients treated using a hyperfractionated regimen with 120 cGy and a median brain dose of 7000 cGy. The real causes of this discrepancy are not known. However, a high sensitivity of the human brain to a change in fraction size may play a role.

Undifferentiated ovarian carcinoma associated with leukemoid reaction

Exceptionally excess leukocytosis or leukemoid reaction may develop in association with carcinomas of the lung and stomach. The authors describe a 72-year-old lady with FIGO stage III ovarian undifferentiated carcinoma who presented with fever and abdominal pain. Her serial WBC counts were up to 143,000/microl with elevated leukocyte alkaline phosphatase score. She received extended total hysterectomy, left salpingo-oophorectomy, and de-bulking of the retroperitoneal mass. Her left ovarian cancer was composed of diffuse sheets of large undifferentiated cells that were immunoreactive for cytokeratin, confirming the epithelial nature. She passed away one week after operation and five weeks after presentation without autopsy. This is the first report of ovarian cancer associated with leukemoid reaction in the English literature.

Up-regulation of Fas ligand expression by human cytomegalovirus immediate-early gene product 2: a novel mechanism in cytomegalovirus-induced apoptosis in human retina

Human CMV (HCMV) is an important pathogen that causes widespread diseases in immunocompromised individuals. Among the opportunistic HCMV infections, HCMV retinitis is most common in transplant recipients and AIDS patients. It often leads to blindness if left untreated. The question as to how HCMV infection causes retinal pathogenesis remains unresolved. Here, we report that viral immediate-early gene product 2 (IE2), but not IE1, up-regulates the Fas ligand (FasL) expression in HCMV-infected human retinal pigment epithelium cells. Increased secretion of FasL from virally infected cells into cultured medium was observed upon HCMV infection. The capability of such cell-free medium to induce apoptosis of Fas (CD95)-expressing Jurkat cells further implies that Fas-FasL interaction might mediate cell death in the lesion of HCMV retinitis. To support this idea, we observed augmented soluble FasL levels in vitreous from AIDS patients with HCMV retinitis as compared with that from AIDS patients without HCMV infection. In addition, by in situ hybridization and immunohistochemistry, we detected enhanced signals of FasL, the existence of viral IE Ags and apoptotic cells at the same sites in the lesion of HCMV-infected retina. These results strongly suggest that IE2 induction of FasL expression in human retina might be an important event that takes place in the early stage of infection and finally leads to visual loss in individuals affiliated with HCMV retinitis.

Inhibition of group A streptococcus infection by carboxyfullerene

The effect of a water-soluble trimalonic acid derivative of fullerene, carboxyfullerene, against Streptococcus pyogenes infection was tested. Pretreatment with carboxyfullerene was able to protect mice from S. pyogenes infection in an air pouch model. S. pyogenes-induced death and skin injury were inhibited dose dependently by carboxyfullerene. Administration of carboxyfullerene via the peritoneum and air pouch at 3 h post-S. pyogenes infection was able to protect 33% of mice from death. Surveys of exudates of the air pouch of carboxyfullerene-treated mice revealed that survival of infiltrating neutrophils was prolonged and that the bacteria were eliminated as a result of enhanced bactericidal activity of the neutrophils. Furthermore, carboxyfullerene was able to directly inhibit in vitro growth of S. pyogenes. These data suggest that carboxyfullerene can be considered an antimicrobial agent for group A streptococcus infection.

Immunopathogenesis of dengue virus infection

Dengue virus infection causes dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS), whose pathogeneses are not clearly understood. Current hypotheses of antibody-dependent enhancement, virus virulence, and IFN-gamma/TNFalpha-mediated immunopathogenesis are insufficient to explain clinical manifestations of DHF/DSS such as thrombocytopenia and hemoconcentration. Dengue virus infection induces transient immune aberrant activation of CD4/CD8 ratio inversion and cytokine overproduction, and infection of endothelial cells and hepatocytes causes apoptosis and dysfunction of these cells. The coagulation and fibrinolysis systems are also activated after dengue virus infection. We propose a new hypothesis for the immunopathogenesis for dengue virus infection. The aberrant immune responses not only impair the immune response to clear the virus, but also result in overproduction of cytokines that affect monocytes, endothelial cells, and hepatocytes. Platelets are destroyed by crossreactive anti-platelet autoantibodies. Dengue-virus-induced vasculopathy and coagulopathy must be involved in the pathogenesis of hemorrhage, and the unbalance between coagulation and fibrinolysis activation increases the likelihood of severe hemorrhage in DHF/DSS. Hemostasis is maintained unless the dysregulation of coagulation and fibrinolysis persists. The overproduced IL-6 might play a crucial role in the enhanced production of anti-platelet or anti-endothelial cell autoantibodies, elevated levels of tPA, as well as a deficiency in coagulation. Capillary leakage is triggered by the dengue virus itself or by antibodies to its antigens. This immunopathogenesis of DHF/DSS can account for specific characteristics of clinical, pathologic, and epidemiological observations in dengue virus infection.

Sensitivity of vagal afferent endings to chemical irritants in the rat lung

This study was carried out to investigate the relationship between the conduction velocity of the vagal afferents arising from the rat lungs and their sensitivities to capsaicin, other chemical irritants, and lung inflation. We recorded single-unit activities of vagal pulmonary afferents (n = 205) in anesthetized, open-chest rats, and distinguished C fibers (conduction velocity < 2 m/sec) from myelinated afferents; the latter group was further classified into rapidly adapting pulmonary receptors (RARs) and slowly adapting pulmonary stretch receptors (SARs) on the basis of their adaptation indexes to lung inflation. Right-atrial injection of capsaicin (1 microg/kg) evoked an abrupt and intense stimulatory effect in 88.9% (64/72) of the pulmonary C fibers tested, but only a mild stimulation in 6.3% (3/48) of the RARs and none of the SARs. Other inhaled and injected chemical stimulants (e.g., cigarette smoke, lactic acid) activated 68.9% (42/61) of the pulmonary C fibers. The same chemical irritants exerted a mild stimulatory effect in only 14.5% (8/55) of the RARs; this subgroup of RARs exhibited a low or no baseline activity, and half of them were located near the hilum. Chemical stimulants had little or no effect on SARs. The response of pulmonary C fibers to lung inflation (tracheal pressure = 30 cm H2O) was not only extremely weak, but also showed a longer onset latency and an irregular pattern. In a sharp contrast, lung inflation evoked rapid and vigorous discharges in both RARs and SARs. In conclusion, C fibers are the primary type of chemosensitive vagal pulmonary afferents in rat lungs.

Human physiologic factors in respiratory uptake of 1,3-butadiene

1,3-Butadiene (BD), a suspected human carcinogen, is used as the raw material in industries to make synthetic butyl rubber and plastics. Simulation models using experimental animal data have shown that physiologic factors play an important role in the kinetic behavior of BD. However, human data are limited. The aim of this inhalation study was to identify influential human physiologic factors in the respiratory uptake of BD. We recruited 133 healthy volunteers in Boston, Massachusetts, into this study and tested them under an approved human subjects protocol. Each subject was exposed to 2 ppm (4.42 mg/m3) BD for 20 min, followed by purified air for another 40 min. Five exhaled breath samples collected during exposure were used to determine the respiratory uptake of BD, which was defined as absorbed BD (micrograms) per kilogram of body weight during exposure. Although subjects were given identical administered doses (40 ppm x min), there was a wide range of uptake, 0.6-4.9 microg/kg. Of the studied physiologic factors, the blood:air partition coefficient and alveolar ventilation were most significant in determining the respiratory uptake (p < 0.001 for each). In addition, in the multiple regression analysis, females had significantly higher respiratory uptake of BD than males on a weight basis. For all subjects, increasing age and cigarette smoking led to significantly decreased respiratory uptake of BD. The results of this human study are consistent with previous kinetic simulations and animal studies. The findings also suggest that interindividual variation in human physiologic factors that affect the exposure-internal dose relationship should be considered while also exploring exposure-disease associations in future epidemiologic research.

Observation of large CP violation in the neutral B meson system

We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.

Roles of I-E molecule and CD28 costimulation in induction of suppression by staphylococcal enterotoxin B in vivo

Exposure to bacterial superantigens leads to the induction of a subsequent state of immune hyporesponsiveness. Using a transwell coculture system, a previous report demonstrated that splenocytes from staphylococcal enterotoxin B (SEB)-injected BALB/c mice secreted soluble mediators to suppress the proliferative response of naive syngeneic splenocytes to SEB stimulation. We show in the present study that, in contrast to the suppressive effect induced by SEB in BALB/c (H-2(d) haplotype), MRL(+/+), and MRL-lpr/lpr (H-2(k)) mice, SEB-primed splenocytes from I-E(-) strains such as B6, B10, A. BY (H-2(b)), and A.SW (H-2(s)) mice failed to inhibit the CD25 expression and the proliferative activity of their syngeneic naive responder splenocytes. Further results revealed that the SEB-primed cells from BALB/c, but not B6, mice inhibited the CD25 expression and proliferation of naive responder cells from either BALB/c or B6 mice, indicating the critical regulatory role of the effector cells. Unlike SEB, staphylococcal enterotoxin A induced profound suppression in both BALB/c and B6 mice. Moreover, the suppressive competence of SEB-primed splenocytes was diminished in CD28-deficient BALB/c mice. Taken together, our results indicate that when SEB is used as a stimulator in vivo, both the I-E molecule and CD28 costimulation are required for the induction of regulatory cells bearing suppressive activity.

Alleviation of wood smoke-induced lung injury by tachykinin receptor antagonist and hydroxyl radical scavenger in guinea pigs

We recently reported that wood smoke inhalation initially (within 5 min) causes airway injury and subsequently produces both airway and parenchymal injury after a delay (within 2 h). In this study, we investigated the mediator mechanisms of this delayed smoke-induced lung injury in 126 anesthetized and artificially ventilated guinea pigs who received challenges of either air or 40 tidal breaths of wood smoke. Two hours after inhalation, wood smoke produced various injurious responses, including increases in alveolar-capillary permeability, microvascular permeabilities, and histological injury scores, in airway and parenchymal tissues. Pre-treatment given before smoke challenge with CP-96,345 [a tachykinin NK1 receptor antagonist; (2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxyphenyl)-methyl)-1-aza bicyclo(2.2.2.)-octan-3-amine], dimethylthiourea (a hydroxyl radical scavenger), or a combination of these two drugs largely alleviated both the airway and parenchymal responses, whereas pre-treatment with SR-48,968 [a tachykinin NK2 receptor antagonist; (S)-N-methyl-N(4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophenyl)-butyl)benzamide] or a combination of CP-96,344 and SR-48,965 (inactive enantiomers) failed to do so. Post-treatment given at 5 min after smoke challenge with CP-96,345 or dimethylthiourea significantly alleviated the parenchymal responses, while having no effect on the airway responses. Pre-treatment with dimethylthiourea prevented the smoke-induced reduction in airway neutral endopeptidase activity (an enzyme for tachykinin degradation). We concluded that (1) tachykinins and hydroxyl radical play important roles in producing smoke-induced delayed lung injury in guinea pigs, and both may be involved in the spread of injury from the airways to the pulmonary parenchyma, and (2) the contribution of tachykinins is mediated via the activation of tachykinin NK1 receptors, and is associated with the hydroxyl radical-induced inactivation of airway neutral endopeptidase.

A phylogeny of freshwater eels inferred from mitochondrial genes

The genus Anguilla Shaw of Family Anguillidae consists entirely of freshwater eels, including 15 species and 2 subspecies. Conventionally, variegated markings and the length of the dorsal fin are the major morphological features used for reconstruction of phylogenetic relationships. The evolutionary history of these species remains unclear, especially for the Atlantic eels, whose habitats are far from the Metropolis in the Indo-Pacific region. This study reexamined the phylogenetic relationships of 12 Anguilla species by sequencing of the cytochrome b and 12S rRNA genes. In our analysis, species bearing similar coloration patterns or dorsal fin morphology are not necessarily clustered in the same clade, indicating that these morphological features might be unstable or might have occurred independently in different lineages during evolution. Combining our molecular data and geographical evidence, we speculate that (1) Anguilla first radiated about 20 million years ago, (2) the ancestors of Atlantic eels did not migrate by drifting through the Tethys Seaway at the leptocephali stage but instead trekked across the Central American Isthmus to the Sargasso Sea for spawning at the adult stage, and (3) multiple radiation events had occurred at the Metropolis during Anguilla evolution.

Growth of endothelial cells on different concentrations of Gly-Arg-Gly-Asp photochemically grafted in polyethylene glycol modified polyurethane

To improve endothelial cell adhesion and growth on the surface of polyethylene glycol modified polyurethane (PU-PEG), cell adhesive peptide Gly-Arg-Gly-Asp (GRGD) was photochemically grafted to the surface. The surface grafted GRGD-N-Succinimidyl-6-[4'-azido-2'-nitrophenylamino]hexanoate (SANPAH) on a PU-PEG surface was performed by adsorption and subsequent ultraviolet irradiation. Fourier transform infrared spectra (FTIR) and electron spectroscopy for chemical analysis (ESCA) confirmed the GRGD grafted to form a PU-PEG-GRGD surface. The composition fraction of nitrogen calculated from ESCA analysis for the PU-PEG-GRGD surface was well correlated with the concentration of GRGD to be immobilized. Human umbilical vein endothelial cells (ECs) were well adhered and growing on the PU-PEG-GRGD surface. Moreover, the viability of ECs growing on PU-PEG-GRGD surfaces, analyzed by MTT test, was also well correlated with the GRGD concentrations immobilized on the surface. With photochemical techniques, we could manipulate different contents of GRGD to form multiple regions of PU-PEG-GRGD surface that could enhance the growth of ECs on the surface, and the enhancement efficiency was well correlated with GRGD contents.