Increasing the capacity for treatment of chemical plant wastewater by replacing existing suspended carrier media with Kaldnes Moving Bed media at a plant in Singapore

The Kaldnes biomedia K1, which is used in the patented Kaldnes Moving Bed biofilm process, has been tested along with other types of biofilm carriers for biological pretreatment of a complex chemical industry wastewater. The main objective of the test was to find a biofilm carrier that could replace the existing suspended carrier media and at the same time increase the capacity of the existing roughing filter-activated sludge plant by 20% or more. At volumetric organic loads of 7.1 kg COD/m3/d the Kaldnes Moving Bed process achieved much higher removal rates and much lower effluent concentrations than roughing filters using other carriers. The Kaldnes roughing stage achieved more than 85% removal of organic carbon and more than 90% removal of BOD5 at the tested organic load, which was equivalent to a specific biofilm surface area load of 24 g COD/m2/d. Even for the combined roughing filter-activated sludge process, the Kaldnes carriers outperformed the other carriers, with 98% removal of organic carbon and 99.6% removal of BOD5. The Kaldnes train final effluent concentrations were only 22 mg FOC/L and 7 mg BOD5/L. Based on the successful pilot testing, the full-scale plant was upgraded with Kaldnes Moving Bed roughing filters. During normal operation the upgraded plant has easily met the discharge limits of 100 mg COD/L and 50 mg SS/L. For the month of September 2002, with organic loads between 100 and 115% of the design load for the second half of the month, average effluent concentrations were as low as 9 mg FOC/L, 51 mg COD/L and 12 mg SS/L.

Nanostructured Ti-based multi-component alloys with potential for biomedical applications

A group of Ti(60)Cu(14)Ni(12)Sn(4)M(10) (M=Nb, Ta, Mo) alloys was prepared using arc melting and copper mold casting. The as-prepared alloys have a composite microstructure containing a micrometer-sized dendritic beta-Ti(M) phase dispersed in a nanocrystalline matrix. These new alloys exhibit a low Young's modulus in the range of 59-103 GPa, and a high yield strength of 1037-1755 MPa, together with large plastic strains. The combination of high strength and low elastic modulus offers potential advantages in biomedical applications.

Stimulation of PAI-1 and adipokines by glucose in human adipose tissue in vitro

Adipokines such as Plasminogen activator inhibitor-1 (PAI-1), interleukin (IL)-8, and tumor necrosis factor (TNF)-alpha are elevated in patients with obesity, insulin resistance, and type 2 diabetes. In the present study, we investigated whether glucose affected the production of these adipokines in human adipose tissue in vitro. Glucose (up to 35mM) increased secretion of PAI-1 (p<0.01) and IL-8 (p<0.01), but not TNF-alpha, in a dose- and time-dependent manner. Half-maximal stimulatory concentration of glucose was about 1mM. Glucosamine (5mM) decreased production of PAI-1 (p<0.05) and IL-8 (p<0.05), indicating that the hexosamine biosynthesis pathway is not involved in the glucose-induced increment in adipokine secretion. The present data demonstrate that glucose increases PAI-1 and IL-8 secretion. However, glucose concentrations above 5mM had no additional effects on adipokine secretion, suggesting that mechanisms other than diabetes/insulin resistance-related hyperglycemia may be involved in the observed elevation of these adipokines.

Fracture mechanisms in bulk metallic glassy materials

We find that the failure of bulk metallic glassy (BMG) materials follows three modes, i.e., shear fracture with a fracture plane significantly deviating from 45 degrees to the loading direction, normal tensile fracture with a fracture plane perpendicular to the loading direction, or distensile fracture in a break or splitting mode with a fracture plane parallel to the loading direction. The actually occurring type of failure strongly depends on the applied loading mode and the microstructure of the material. Extensive evidence indicates that the Tresca fracture criterion is invalid, and for the first time, three fracture criteria are developed for isotropic materials with high strength, such as advanced BMGs or the newly developed bulk nanostructural materials.

Differences in plasminogen activator inhibitor 1 in subcutaneous versus omental adipose tissue in non-obese and obese subjects

Human adipose tissue can produce plasminogen activator inhibitor-1 (PAI-1). It has been suggested that high levels of PAI-1 are of importance in enhanced cardiovascular disease observed among obese subjects, especially abdominally obese individuals. In the present study, we investigated the level of mRNA and production of PAI-1 in adipose tissue from two adipose tissue depots (omental vs. subcutaneous). Adipose tissue from both depots was obtained from obese (mean BMI, 46.9 kg/m 2) and non-obese (mean BMI, 23.9 kg/m 2) women. PAI-1 mRNA was measured both in fresh adipose tissue obtained immediately after surgery and after the adipose tissue (fragments) had been incubated for up to 72 h. In immediately frozen adipose tissue, PAI-1 mRNA expression was similar in omental and subcutaneous adipose tissue. No differences between obese and non-obese women were found. However, when adipose tissue fragments were cultured, PAI-1 mRNA and PAI-1 production were significantly higher in omental than in subcutaneous adipose tissue (p < 0.05). In the culture system, the production of PAI-1 in obese subjects was higher than in non-obese subjects in both subcutaneous (p < 0.05) and in omental adipose tissue (p = 0.19). In order to test whether these regional differences observed after incubation of the adipose tissue were due to differences in local accumulation of cytokines that may stimulate PAI-1 by a paracrine or autocrine manner, we investigated the expression of transforming growth factor beta1 (TGF-beta1) mRNA and tumor necrosis factor alpha (TNF-alpha) mRNA and protein. No differences between the two fat depots were found. In conclusion, no differences in PAI-1 expression between omental and subcutaneous adipose tissue were observed in biopsies frozen immediately after removal, but after incubation of adipose tissue (which somehow stimulates PAI-1 production), higher levels of PAI-1 were found in omental adipose tissue than in subcutaneous adipose tissue. Finally, PAI-1 production in adipose tissue from obese women was higher in non-obese women after incubation for 72 h.

Metformin, but not thiazolidinediones, inhibits plasminogen activator inhibitor-1 production in human adipose tissue in vitro

Biguanides and thiazolidinediones (TZDs), which are primarily used as anti-diabetic drugs, are also associated with other beneficial effects on cardiovascular risk factors such as reduced plasma plasminogen activator inhibitor-1 (PAI-1) concentration in both diabetic and non-diabetic obese subjects. Since human adipose tissue is of importance for the production of PAI-1, the aim of the present study was to investigate the possible direct effects of these anti-diabetic agents on PAI-1 mRNA and secretion by human adipose tissue. Adipose tissue was obtained from biopsies taken from the subcutaneous abdominal depot. Adipose tissue fragments, isolated mature adipocytes, and preadipocytes were incubated in vitro with metformin and various TZDs. Metformin (0.1 - 10 mM) dose-dependently decreased PAI-1 production (and PAI-1 mRNA) under both basal (43 % inhibition at 10 mM, p < 0.05) and interleukin-1beta (IL-1beta)-stimulated conditions where the levels were inhibited by 47.8 % at 1 mM metformin (p < 0.05) and by 100 % at 10 mM (p < 0.01). None of the TZDs tested (PPAR-gamma agonists: troglitazone, pioglitazone, or ciglitazone) had any effects on PAI-1 production. Moreover, no effects on PAI-1 production were observed using various PPAR-alpha agonists such as 5, 8, 11, 14-eicosatetraynoic acid (ETYA), Wy14643 and fenofibrate. Our findings indicate no direct effects of TZDs on PAI-1 secretion, whereas metformin was able to directly inhibit PAI-1 production in human adipose tissue.

[Protection of naoyi-an granule in ischemic brain injury secondary to intracerebral hemorrhage in rats]

AIM

To explore the protective effect and its mechanism of the traditional Chinese medicine complex, naoyi-an granule(NYAG), on intracerebral hemorrhage(ICH) in rats.

METHODS

Collagenase-induced ICH rats were used. Inducible nitric oxide synthase(iNOS) activity of ischemic cerebral cortex surrounding the intracerebral hematoma was assayed by monitoring the conversion of L-3H-arginine to L-3H-citrulline. Pathologic changes in the same area were observed with transmission electron microscope on the 2nd day, the 4th day and the 7th day after ICH.

RESULTS

The iNOS activities of NYA-treated group decreased remarkably(P < 0.01) compared with those of the saline-treated group. Ultrastructural observation also indicated that NYAG ameliorated the brain edema, cell degeneration and necrosis.

CONCLUSIONS

The inhibitory effect of NYAG on iNOS activity may be related to its protection against ischemic brain injury secondary to ICH.

Inhibitory effect of ZnCl(2) on glycolysis in human oral microbes

Although the inhibition of bacterial glycolysis by zinc ions might be expected to moderate dental caries, there has not been a comparison of the effect of Zn on different organisms under both fixed pH and free-fall conditions. Here, the effect of ZnCl(2) on Streptococcus salivarius, Strep. mutans, Strep. sobrinus, Actinomyces naeslundii and Lactobacillus casei, as well as on mixtures of oral organisms outgrown from human dental plaque and saliva, was surveyed. pH-stat experiments were performed at pH 7, 6 or 5 in a solution containing 5% glucose and a suspension of the test organism; pH-fall experiments started at pH 7. In both cases, acid production was monitored for 60 min, when samples were taken for Zn and lactate determinations. Under pH-stat conditions, acid production was inhibited by Zn most strongly in Strep. sobrinus and Strep. salivarius. In terms of total acid production averted, however, the effect of Zn under both pH-stat and pH-fall conditions was clearly greatest with Strep. salivarius. A. naeslundii was inhibited the least strongly under pH-stat conditions. Cultured oral organism mixtures were more sensitive to moderate concentrations of zinc (0.2-0.3mM initial concentration) than were the single species to higher concentrations (1mM). Packed cell layers responded to Zn quite differently from suspensions, the pH often falling in the presence of 1mM Zn at a rate similar to the no Zn control. As streptococci had the highest acidogenesis rates in both pH-stat and pH-fall experiments, it seems likely that inhibition of acid production with these organisms would be of more value in moderating caries than the inhibition of less acidogenic organisms such as A. naeslundii.

[A comparison of the kinetic characters of NT-3, NT-4 and BDNF retrogradely transported in facial nerve]

OBJECTIVE

To compare the kinetic characters of retrograde transport of neurotrophin-3 (NT-3), neurotrophin-4 (NT-4) and brain-derived neurotrophin factor (BDNF) in facial nerve.

METHODS

Radioactive tracer technique was used. After one lateral facial nerve trunk of adult rabbit was transected, a silicone chamber was inserted between the stumps, and 3.7 MBq of 125I-NT-3 or 125I-NT-4 or 125I-BDNF or 125I-HSA was administered into the chamber. At different time-points after injection, the facial nerve trunk and facial nerve motor neurone of brain-stem were collected and the uptake rates were measured. The kinetic parameters of each labeled compound were calculated using 3P87 program of kinetics.

RESULTS

The transport amount of neurotrophin retrogradely transported by facial nerve is NT-3 > BDNF > NT-4 (P < 0.05), the transport rate is NT-4 > NT-3 > BDNF (P < 0.05).

CONCLUSION

The findings could serve as the kinetic characters of retrograde transport of neurotrophins.

Bimodal effects of 1R,2R-diaminocyclohexane(trans-diacetato)(dichloro)platinum(IV) on cell cycle checkpoints

1R,2R-Diaminocyclohexane(trans-diacetato)(dichloro)-platinum(IV) (DACH-acetato-Pt) is a novel platinum-based agent that is highly effective against cisplatin-resistant ovarian tumor cells. To probe its cellular mechanism, the effects of DACH-acetato-Pt (0-6.4 microM) on cell cycle checkpoints were examined using the ovarian cancer A2780 cell line as the model system. We found that DACH-acetato-Pt at > or =0.2 microM dramatically inhibited cell growth and induced cell death. At concentrations < or =0.6 microM (low effective concentrations), DACH-acetato-Pt specifically induced G(1) phase arrest by selectively inhibiting cyclin-dependent kinase 4 (Cdk4) and Cdk2 activities. The Cdc2 activity, which regulates G(2)-M phase progression, was unaffected by the drug at these concentrations. At concentrations >0.6 microM (high effective concentrations), DACH-acetato-Pt first transiently inhibited S-phase progression and then blocked cell cycle progression at both G(1) and G(2) phases. These cell cycle effects were associated with sequential inhibitions of Cdk2/cyclin A activity, Cdk4 and Cdk2 activities, and Cdc2 kinase activity. Following the cell cycle effects, both the low and high effective concentrations of DACH-acetato-Pt induced cell death through apoptosis. These results indicate that DACH-acetato-Pt activates multiple cell cycle checkpoints in a bimodal manner and suggest that the cell cycle effects demonstrated in these studies may be linked to its ability to induce apoptosis.

Cutting edge: membrane lymphotoxin regulates CD8(+) T cell-mediated intestinal allograft rejection

Blocking the CD28/B7 and/or CD154/CD40 costimulatory pathways promotes long-term allograft survival in many transplant models where CD4(+) T cells are necessary for rejection. When CD8(+) T cells are sufficient to mediate rejection, these approaches fail, resulting in costimulation blockade-resistant rejection. To address this problem we examined the role of lymphotoxin-related molecules in CD8(+) T cell-mediated rejection of murine intestinal allografts. Targeting membrane lymphotoxin by means of a fusion protein, mAb, or genetic mutation inhibited rejection of intestinal allografts by CD8(+) T cells. This effect was associated with decreased monokine induced by IFN-gamma (Mig) and secondary lymphoid chemokine (SLC) gene expression within allografts and spleens respectively. Blocking membrane lymphotoxin did not inhibit rejection mediated by CD4(+) T cells. Combining disruption of membrane lymphotoxin and treatment with CTLA4-Ig inhibited rejection in wild-type mice. These data demonstrate that membrane lymphotoxin is an important regulatory molecule for CD8(+) T cells mediating rejection and suggest a strategy to avoid costimulation blockade-resistant rejection.

Treatment of rotaviral gastroenteritis with Qiwei Baizhu powder

AIM: To observe the effects of Qiwei Baizhu Powder (QWBZP) on rotaviral gastroenteritis in children and in animal models.

METHODS: Enrolled patients were divided into two groups, and one group was treated with oral rehydration solution (ORS) and the other treated with oral liquid of QWBZP. Neonate mice were orally infected with 50 μL rotavirus suspension (4 × 10⁸ PFU/mL) and treated with ORS or oral liquid of QWBZP, respectively.

RESULTS: Eighty-three cases of rotaviral gastroenteritis treated with QWBZP revealed a better efficacy than that treated with ORS (χ² = 10.87, P ＜ 0.05). The contents of sodium and glucose as well as number of patients with positive human rotavirus antigen in stool in QWBZP group were all less than that in ORS group. In animal models, QWBZP was found effective in treating rotavirus gastroenteritis in neonate NIH mice, as compared with control groups. In QWBZP group, the mortality of infected mice was decreased by 73.3%, the body weight of infected mice was increased, the contents of sodium and glucose as well as number of mice with positive rotavirus antigen in feces were significantly reduced, and the pathological changes such as damage of small intestinal mucosa and villi were also obviously alleviated.

CONCLUSION: QWBZP has effects on improving the absorptive function of small intestine, shortening the duration of diarrhea and rotavirus shedding from stool and alleviating the pathological changes of small intestine induced by rotavirus.

Optical properties of single-walled 4 A carbon nanotubes

Optical properties of a series of finite sized hydrogenated carbon nanotubes with the smallest diameter of 4 A are studied systematically. Their absorption spectra are calculated with the localized-density-matrix method. The semiempirical MNDO parametric method 3 (PM3) Hamiltonian is employed. The finite optical gaps are predicted for the infinite long single-walled carbon nanotubes. Strong anisotropy characteristics of the dynamic polarizabilities are found for these tubes. The calculated results are in good agreement with the recent experimental findings. Further the compositions of the dipole-induced excitations are examined by projecting the corresponding density matrices onto the Hartree-Fock molecular orbital representation. Unlike the larger diameter carbon nanotubes whose absorption spectra are insensitive to the tube chiralities, the absorption spectra of 4 A single-walled carbon nanotubes depend very much on their chiralities. The chirality of the single-walled 4 A carbon nanotubes synthesized in the channels of the porous zeolites is thus determined to be (5,0) by comparing the calculated and measured absorption spectra.

[A comparative observation preoperatively and postoperatively of nasal mucosa in chronic sinusitis treated with endoscopic sinus surgery]

OBJECTIVES

To study morphologic and functional mucosal changes both preoperatively and postoperatively in chronic sinusitis (CS) treated with endoscopic sinus surgery (ESS).

METHODS

1. Saccharin test and light microscopic examination of nasal mucosa were taken preoperatively and postoperatively in 32 cases with CS and in 28 normal subjects as control. 2. Scanning and transmission electron microscopy were performed to exam preoperatively and postoperatively the nasal mucosa in 10 cases with CS and in 2 normal cases as control.

RESULTS

1. The preoperative saccharin test time (STT) in patients with CS was significantly longer than that in the controls (P < 0.001), and the postoperative STT became significantly shorter than that in preoperative one(P < 0.001). 2. The pathological changes of nasal mucosa, such as infiltration in inflammatory cells, edema, polypoid formations and pathologic glands were observed preoperatively. The infiltration in inflammatory cells, edema and polypoid formations were significantly released (P < 0.01) at four months after operation, and there was no significant difference comparing with the controls (P > 0.05). However, the pathologic glands were not reduced even after four months postoperatively. 3. The examination of electron microscopy demonstrated that the ultrastructure of nasal mucosa was impaired preoperatively and almost completely recovered at four months postoperatively.

CONCLUSIONS

The normal structure and clearance function of nasal mucosa in patients with CS was impaired preoperatively, and the impaired structure and mucociliary clearing function of nasal mucosa were greatly improved after ESS and almost completely recovered at four months postoperatively. The pathologic glands and secretive function of nasal mucosa may need longer period for recovering.

Tumorhead, a Xenopus gene product that inhibits neural differentiation through regulation of proliferation

Tumorhead (TH) is a novel maternal gene product from Xenopus laevis containing several basic domains and a weak coiled-coil. Overexpression of wild-type TH resulted in increased proliferation of neural plate cells, causing expansion of the neural field followed by neural tube and craniofacial abnormalities. Overexpressed TH protein repressed neural differentiation and neural crest markers, but did not inhibit the neural inducers, pan-neural markers or mesodermal markers. Loss of function by injection of anti-TH antibody inhibited cell proliferation. Our data are consistent with a model in which tumorhead functions in regulating differentiation of the neural tissues but not neural induction or determination through its effect on cell proliferation.

[A study of on the transport of neurotrophin-4 in facial nerve]

OBJECTIVE

This is a study on the transport information of neurotrophin-4 (NT-4) in facial nerve using radioactive tracer technique.

METHODS

After one lateral facial nerve trunk of adult rabbit was transected, a silicone chamber was inserted between the stumps, and 7.4 MBq of 131I-NT-4 was administered into the chamber. At the distinct moment of post-injection, the head of one rabbit was imaged at coronary position, the bilateral facial nerve trunk and brain-stem of the others were collected and counted respectively. After 1 mg of brain-derived neurotrophic factor (BDNF) and 7.4 MBq of 131I-NT-4 were administered into the chamber of one rabbit, the rabbit was imaged at coronary position of head at distinct moment.

RESULTS

5.08% of 131I-NT-4 was transported into facial nerve trunk at 4 h of post-injection. 131I-NT-4 presented high peak in facial nerve trunk during the period of 8, 12 h, the peak values were 20.58% and 22.74% respectively. 34.75% and 45.57% of 131I-NT-4 were transported into the brain-stem of experimental side at 8 h and 12 h respectively. The transport of 131I-NT-4 was markedly restrained by BDNF in facial nerve.

CONCLUSION

NT-4 displays a receptor-mediated retrograde transport in facial nerve.

A bridged loop-gap S-band surface resonator for topical EPR spectroscopy

The design and structure of a bridged loop-gap surface resonator developed for topical EPR spectroscopy and imaging of the distribution and metabolism of spin labels in in vivo skin is reported. The resonator is a one-loop, one-gap bridged structure. A pivoting single loop-coupling coil was used to couple the microwave power to the loop-gap resonant structure. A symmetric coupling circuit was used to achieve better shielding and minimize radiation. The frequency of the resonator can be easily adjusted by trimming the area of the capacitive foil bridge, which overlaps the gap in the cylindrical loop. The working frequency set was 2.2 GHz and the unloaded Q was 720. The B1 field of this resonator was measured and spatially mapped by three-dimensional EPR imaging. The resonator is well suited to topical measurements of large biological subjects and is readily applicable for in vivo measurements of free radicals in human skin.

[Study on the transformation from myelodysplastic syndromes into acute leukemias]

OBJECTIVE

To study the patterns of transformation from myelodysplastic syndromes (MDS) into acute leukemias (AL).

METHODS

Leukemic transformation of MDS patients was dynamically followed up and the clinical manifestations, peripheral blood and bone marrow pictures, karyotypes, immunophenotypes, response to treatment and prognosis of post MDS acute leukemia (postMDS-AL) were observed.

RESULTS

During the past eight year and seven months, 21 (13.91%) of 151 MDS patients progressed to overt leukemia with a median interval of 5 (1 - 21) months. There were no significant differences among the rates of leukemia from RA, RAEB and RAEB-t groups. The transformation was developed either gradually or rapidly. There were five parameters related to the leukemic transformation: under 40 years of age, pancytopenia, more than 0.15 blasts in bone marrow, at least two types of abnormal karyotype and combined chemotherapy. All of the 21 post MDS-AL were acute myeloid leukemia (AML); and most of them were M(2), M(4) and M(5). Two (9.52%) post MDS-AML developed extramedullary infiltration. Leukopenia was found in 47.62% of patients. Two third of the patients, whose bone marrows were generally hypercellular, showed neutropenias. After evolving into AML, 8 (47.06%) patients developed abnormal karyotypes. High expression of immature myeloid antigens, including CD(33) (49.83 +/- 24.50)%, CD(13) (36.38 +/- 33.84)%, monocytic antigen CD(14) (38.50 +/- 24.60)%, and stem cell marker CD(34) (34.67 +/- 30.59)% were found on bone marrow mononuclear cells of post MDS-AML cases. In some cases, lymphoid antigens, such as CD(5), CD(7), CD(9) and CD(19) were coexisted with myeloid antigens. A low complete remission rate (31.25%) and short survival duration with median survival of 6 (1 - 28) months were found in patients with post MDS-AML treated by induction therapy.

CONCLUSION

MDS was at high risk of evolving into AML, either gradually or rapidly. Patients with post MDS-AML had specific biologic features and worse prognoses.

Src is an important mediator of extracellular signal-regulated kinase 1/2-dependent growth signaling by angiotensin II in smooth muscle cells from resistance arteries of hypertensive patients

The role of c-Src in growth signaling by angiotensin (Ang) II was investigated in vascular smooth muscle cells (VSMCs) from arteries of hypertensive patients. c-Src and extracellular signal-regulated kinase 1/2 (ERK1/2) activity, proto-oncogene expression, activating protein-1 (AP-1) DNA-binding activity, and DNA and protein synthesis were studied in Ang II-stimulated VSMCs derived from small peripheral resistance arteries of normotensive subjects (NTs, n=5) and age-matched untreated hypertensive patients (HTs, n=10). Ang II type 1 (AT(1)) and type 2 (AT(2)) receptor status was also assessed. Ang II dose-dependently increased the synthesis of DNA and protein, with enhanced effects in VSMCs from HTs. PD 098,059, a selective inhibitor of the ERK1/2 pathway, attenuated Ang II-stimulated growth in HTs. The effects of PD 098,059 were greater in HTs than in NTs. In NTs, Ang II transiently increased ERK1/2 phosphorylation, whereas in HTs, Ang II-stimulated actions were augmented and sustained. PP2, a selective Src inhibitor, reduced ERK1/2 activity and normalized ERK1/2 responses in HTs. Ang II-induced c-Src phosphorylation was 2- to 3-fold greater in HTs than in NTs. In HTs but not NTs, kinase activation was followed by overexpression of c-fos and enhanced AP-1 DNA-binding activity. PD 098,059 and PP2 attenuated these responses. AT(1) receptor expression was similar in NTs and HTs. In HT cells transfected with c-fos antisense oligodeoxynucleotide, Ang II-stimulated growth was reduced compared with sense oligodeoxynucleotide. Our findings suggest that augmented Ang II-stimulated VSMC growth is mediated via hyperactivation of c-Src-regulated ERK1/2-dependent pathways, leading to overexpression of c-fos mRNA and enhanced AP-1 DNA-binding activity. Because AT(1) receptor expression was unaltered in HTs, increased Ang II signaling may be a postreceptor phenomenon. These data define a signal transduction pathway whereby Ang II mediates exaggerated growth in VSMCs from HTs.

Overexpression of Hp95 induces G1 phase arrest in confluent HeLa cells

Xp95, a protein recently identified in Xenopus laevis, is potentially involved in progesterone-induced Xenopus oocyte maturation. In this study, we cloned a human homologue of Xp95, designated Hp95, and examined the effect of its overexpression on the growth properties of human malignant HeLa cells which have lost the contact inhibition of cell proliferation. We observed that although HeLa cells did not undergo G1 phase arrest at any stage after confluence, they were able to downregulate their G1 phase CDK activities in response to confluence. When Hp95 was overexpressed in HeLa cells by transfection with a constitutive or an inducible expression vector containing a full-length Hp95 transgene, HeLa cells became able to undergo G1 phase arrest and form a monolayer culture after confluence. However, the G1 phase CDK activities in these Hp95 overexpressing cells were not inhibited further as compared to control cells after confluence. These results indicate that the defects in HeLa cells that cause the loss of contact inhibition of cell proliferation are in components downstream of the G1 phase CDKs and that overexpression of Hp95 counteracts some of these defects.

CD8 T cell-mediated rejection of intestinal allografts is resistant to inhibition of the CD40/CD154 costimulatory pathway

BACKGROUND

Disruption of the CD40/CD154 pathway inhibits rejection in numerous models. The importance of this pathway on intestinal allograft rejection was examined in this study.

METHODS

Intestinal grafts from B6C3F1 mice transplanted into C57BL/6 recipients were assessed histologically for rejection.

RESULTS

The monoclonal antibody to CD154, MR1, failed to inhibit rejection in wild-type mice. Similarly, CD154-/- recipient mice rejected intestinal allografts. MR1 did inhibit early rejection in CD8-/- mice, but had no effect in CD4-/- recipients. All MR1-treated CD8-/- recipients eventually developed rejection. No benefit was observed when blockade of the CD40/CD154 pathway by MR1 was combined with blockade of the CD28/B7 pathway by mCTLA4Ig.

CONCLUSIONS

These data suggest that CD4+ T cells mediating intestinal allograft rejection may be more dependent upon the CD40/CD154 pathway than CD8+ T cells. This finding highlights the importance of identifying agents that suppress CD8+ T cell-mediated rejection.

[Sequential intensified immunosuppressive therapy combining with hematopoietic growth factors in the treatment of severe aplastic anemia]

OBJECTIVE

To explore more effective regimen for reducing early mortality of severe aplastic anemia (SAA) and improving therapeutic effectiveness.

METHODS

Antilymphocyte globulin/antithymocyte globulin (ALG/ATG) and cyclosporine A (CsA) (sequential intensified immunosuppressive therapy, SIIST), with or without hematopoietic growth factors (HGFs) were administered to 73 SAA patients in a prospective randomized clinical trial to test the effectiveness of the addition of HGFs for the patients.

RESULTS

The response rate of SIIST with HGFs group was significantly higher than that of SIIST alone group (89.2% vs 63.9%), with lower rates of early infection (24.3% vs 55.3%) and mortality (4.0% vs 16.7%), shorter duration of cytopenia and blood transfusion dependence and faster recovery of bone marrow hematopoiesis. The addition of HGFs to SIIST was tolerated well in all patients. There was no difference in the treatment outcome of the two groups with GM-CSF plus Epo or G-CSF plus Epo.

CONCLUSION

The use of HGFs in combination with SIIST could reduce early infection and mortality rates and, therefore, improve the response rates in SAA patients.

Development of a resonator with automatic tuning and coupling capability to minimize sample motion noise for in vivo EPR spectroscopy

EPR spectroscopy has been applied to measure free radicals in vivo; however, respiratory, cardiac, and other movements of living animals are a major source of noise and spectral distortion. Sample motions result in changes in resonator frequency, Q, and coupling. These instabilities limit the applications that can be performed and the quality of data that can be obtained. Therefore, it is of great importance to develop resonators with automatic tuning and automatic coupling capability. We report the development of automatic tuning and automatic coupling provisions for a 750-MHz transversely oriented electric field reentrant resonator using two electronically tunable high Q hyperabrupt varactor diodes and feedback loops. In both moving phantoms and living mice, these automatic coupling control and automatic tuning control provisions resulted in an 8- to 10-fold increase in signal-to-noise ratio.

Role of c-Src in the regulation of vascular contraction and Ca2+ signaling by angiotensin II in human vascular smooth muscle cells

OBJECTIVE

Tyrosine kinases, typically associated with growth-signaling pathways, also play a role in Ang II-stimulated vascular contraction. However the specific kinases involved are unclear. We hypothesize here that c-Src, a non-receptor tyrosine kinase, is an important upstream regulator of vascular smooth muscle cell (VSMC) Ca2+ signaling and associated vascular contraction induced by Ang II.

METHODS

Cultured VSMCs from resistance arteries of healthy subjects were studied. Human VSMCs electroporated with anti-c-Src antibody and c-Src-deficient VSMCs from small arteries of c-Src knockout mice (Src-/-mVSMCs) were also investigated. Intracellular free Ca2+ concentration ([Ca2+]i), c-Src activity and IP3 production were measured by fura 2, immunoblot and radioimmunoassay respectively. Contraction was examined in intact rat small arteries.

RESULTS

Ang II rapidly increased VSMC c-Src activity, with peak responses obtained at 1 min. Ang II induced a biphasic [Ca2+]i response (Emax = 636 +/- 123 nmol/l). The initial [Ca2+]i transient, mediated primarily by Ca2+mobilization, was dose-dependently attenuated by the selective Src inhibitor, PP2, but not by PP3 (inactive analogue). Ang II-elicited [Ca2+]i responses were blunted in cells electroporated with anti-c-Src antibodies and in c-Src-/-mVSMCs. Src inhibition decreased Ang II-induced generation of IP3 in human VSMCs. Ang II dose-dependently increased vascular contraction (Emax = 40 +/- 6.5%). These responses were attenuated by PP2 (Emax = 7.8 +/- 0.08%) but not by PP3 (Emax = 35 +/- 4.5%).

CONCLUSIONS

Our findings identify c-Src as an important regulator of VSMC [Ca2+]i signaling and implicate a novel contractile role for this non-receptor tyrosine kinase in Ang II-stimulated vascular smooth muscle.

Differential activation of extracellular signal-regulated protein kinase 1/2 and p38 mitogen activated-protein kinase by AT1 receptors in vascular smooth muscle cells from Wistar-Kyoto rats and spontaneously hypertensive rats

OBJECTIVES

The present study investigates effects of angiotensin II on activation of extracellular signal-regulated protein kinase (ERK) 1/2, p38 mitogen activated-protein kinase (p38MAPK) and c-Jun amino terminal kinase (JNK) in vascular smooth muscle cells from spontaneously hypertensive rats (SHR).

METHODS

Vascular smooth muscle cells (VSMC) from mesenteric arteries of Wistar-Kyoto (WKY) rats and SHR were studied. Angiotensin II-induced phosphorylation of ERK1/2, JNK and p38MAPK were assessed by Western blot analysis. c-fos mRNA expression by angiotensin II was determined by reverse transcriptase-polymerase chain reaction in the absence and presence of PD98059, selective inhibitor of ERK1/2-dependent pathways and SB202190, selective p38MAPK inhibitor.

RESULTS

Angiotensin II increased phosphorylation of ERK1/2 and p38MAPK, but not JNK. Responses were significantly increased in SHR compared with WKY. Irbesartan, AT1 receptor antagonist, but not PD123319, AT2 receptor blocker, abolished angiotensin II-induced effects. PP2, selective Src inhibitor, decreased angiotensin II-mediated activation of MAP kinases. Angiotensin II increased c-fos mRNA expression in SHR and had a small stimulatory effect in WKY. These actions were inhibited by PD98059, whereas SB202190 had no effect.

CONCLUSIONS

Angiotensin II-induced activation of vascular ERK1/2 and p38MAPK is increased in SHR. These effects are mediated via AT1 receptors, which activate Src-dependent pathways. Overexpression of c-fos mRNA in SHR is due to ERK1/2-dependent, p38MAPK-independent pathways. Our results suggest that angiotensin II activates numerous MAP kinases in VSMCs and that differential activation of these kinases may be important in altered growth signaling in VSMCs from SHR.

[Immunorelated pancytopenia]

OBJECTIVE

A report of a group of patients with pancytopenia which might be related to abnormal immunity.

METHODS

The clinical and laboratory features of 29 patients with positive bone marrow mononuclear cell (BMMNC) Coombs tests were analyzed.

RESULTS

Most of these cases were pancytopenia with normal or decreased bone marrow cellularities and increased normoblasts. They were all found to have negative results of conventional hemolysis tests and hematopoietic nutrient determination and had no evidence of malignant clonal hematopoiesis. However, all of them showed positive BMMNC-Coombs test and good response to corticosteroids.

CONCLUSION

Immunorelated pancytopenia might be caused by abnormal immunity (especially autoantibody) mediated destruction or abnormal function of blood cells. It is beneficial to differentiate immunorelated pancytopenia from aplastic anemia or myelodysplastic syndromes.

p38 Map kinase regulates vascular smooth muscle cell collagen synthesis by angiotensin II in SHR but not in WKY

Vascular remodeling in hypertension is associated with cell growth and increased deposition of extracellular matrix components, particularly collagen. Mechanisms underlying these processes are unclear, but MAP kinases, particularly ERK1/2 and p38 MAP kinase, may be important. We studied the role of ERK1/2 and p38 MAP kinase in vascular smooth muscle cell (VSMC) collagen synthesis and growth mediated by angiotensin (Ang) II in spontaneously hypertensive rats (SHR). Cultured mesenteric VSMC from Wistar-Kyoto rats and SHR were used. Phosphorylation of ERK1/2 and p38 MAP kinase were assessed by Western blots with phosphospecific antibodies. Ang II-stimulated DNA and collagen synthesis were determined by measuring incorporation of (3)H-thymidine and (3)H-proline, respectively. mRNA expression of procollagen I and III was determined by reverse transcription-polymerase chain reaction. Ang II increased ERK1/2 and p38 MAP kinase phosphorylation. Responses were augmented in SHR. Effects were inhibited by irbesartan, a selective AT(1) antagonist, but not by PD123319, a selective AT(2) blocker. Ang II stimulated (3)H-thymidine and (3)H-proline incorporation. These actions were enhanced 2- to 3-fold in SHR. PD98059, selective inhibitor of the ERK1/2 pathway, attenuated Ang II-induced growth and collagen effects and normalized responses in SHR. SB212190, a selective p38 MAP kinase inhibitor, did not alter Ang II-elicited DNA synthesis but reduced collagen production and mRNA expression of procollagen I and III in SHR. These data demonstrate that (1) Ang II-mediated activation of p38 and ERK1/2 is increased in SHR, (2) augmented growth responses are generated by ERK1/2-dependent, p38 MAP kinase-independent pathways, and (3) p38 MAP kinase influences Ang II-induced collagen production in SHR but not in Wistar-Kyoto rats. These results indicate differential roles of ERK1/2 and p38 MAP kinase in AT(1)-stimulated VSMC growth and collagen production, which may contribute to vascular remodeling in hypertension.

Gene analysis of free fetal DNA in maternal plasma

To investigate the feasibility of using free fetal DNA from maternal plasma as the source of fetal material in non-invasive prenatal diagnosis, SRY gene of free DNA in maternal blood of 65 samples were analyzed by using primer extension preamplication (PEP) and probe microplate hybridization techniques. The results showed that the detection rate of SRY gene in maternal blood from women carrying male fetuses detected by probe microplate hybridization alone and probe microplate hybridization with PEP were 76.09% (35/46) and 95.65% (44/46) respectively, and there was a significant difference between them. The non-detection rate of SRY gene in blood samples from women carrying female fetus was 100% (19/19). It is indicated that probe microplate hybridization was an effective method in detecting trace fetal DNA from maternal plasma and the sensitivity could be substantially improved by combined use of the two techniques. Analysis of fetal DNA in maternal plasma can serve as an alternative for non-invasive prenatal diagnosis.

[mRNA expression and mutation of MTA1 and nm23H1 genes in ovarian carcinoma in relation to lymph node metastasis]

OBJECTIVE

To investigate mRNA expression and mutation of MTA1 and nm23H1 genes in ovarian carcinoma (OC) in relation to lymph node (LN) metastasis.

METHODS

A panel of eight normal ovarian tissues, twenty primary OC specimens and twenty corresponding LNs was examined for mRNA expression and mutation of MTA1 and nm23H1 genes by using RT-PCR and RT-PCR-SSCP. The level of expression was determined by the relative optic density (ROD) of the PCR products.

RESULTS

The frequency of MTA1 overexpression was 100% (7/7) in primary OC with metastasis but only 38.5% (5/13) in those without metastasis (P = 0.0103). Overexpression of MTA1 was observed in 87.5% (6/7) of LNs with metastasis but in only 23% (3/13) of LNs without metastasis (P = 0.0118). In contrast with MTA1, low expression of nm23H1 mRNA was seen in 7 of 7 OC with metastasis but only in 4 of 13 (30%) of those without metastasis (P = 0.0043). Low nm23H1 expression was also seen in 7 of 7 LNs with metastasis but only in 5 of 13 (38.5%) nonmetastatic LNs (P = 0.0102). The ROD ratio of MTA1 to nm23H1 increased with the development of metastasis. No mutation of MTA1 and nm23H1 was found by SSCP analysis.

CONCLUSION

The mRNA expression of MTA1 and nm23H1 is positively and negatively correlated with LN metastasis, respectively. Expression abnormalities but not mutation of the two genes are frequent events related to LN metastasis of ovarian cancer.

In vivo EPR imaging of the distribution and metabolism of nitroxide radicals in human skin

While altered cellular free radical and redox metabolism are critical factors in many human diseases, it has not been previously possible to both measure and image these processes in humans. The development and application of electron paramagnetic resonance instrumentation capable of in vivo spectroscopy and imaging of free radicals in human skin are reported. The instrumentation uses a specially designed topical resonator and a 2.2-GHz microwave bridge. Noninvasive measurements of the distribution and metabolism of the topically applied nitroxide, (15)N-perdeuterated tempone (100 mM), in forearm skin were performed. A single broad peak due to the concentrated label at the skin surface was initially observed, followed by a sharp doublet from the diluted label that permeated the skin. The penetration of the label into the skin and its metabolic clearance were modeled using kinetic equations. It was observed that the penetration process from the skin surface into the dermis and subcutaneous regions, as well as its clearance from these regions, could be described by single exponential functions. Phantom imaging experiments using the nitroxide showed that a spatial resolution of up to 50 microm could be achieved. The skin imaging measurements showed two bands in the distribution of the label along the skin depth. The first band appeared in the outer 400 microm of the skin, the epidermis region, whereas the second band was centered at a depth of 1000 microm in the subcutaneous region with a thickness about 400 microm. These two bands decayed and merged into a single band with time. The results are important in the understanding of the permeability and metabolism of free radicals in human skin.

[Modification of facial mask on the dead space effect in non-invasive mask ventilation]

OBJECTIVE

There were reports concerning the CO2 rebreathing during non-invasive positive pressure ventilation (NIPPV) with full face mask. It is our hypothesis that modification of the mask from one way connection to two ways connection by making a side hole in the mask makes it possible that CO2 inside the mask could be washed out by a constant flow through the mask.

METHODS

A randomized self-control study on CO2 rebreathing was conducted in 7 COPD patients to compare the modified set-up with the conventional one. A BiPAP-30 ventilator and a plateau exhaustion valve (Respironics USA) were employed in the study. In the modified two ways set-up, the exhaustion valve (with distal end blocked) was connected to the side hole of the mask, so that a constant base flow could pass through the mask to the exhaustion valve. The average base flow was 0.43 LPS. The parameters were set as following: S/T mode, f: 15 BPM, pressure support level: 8 cm H2O. Three different levels of PEEP (2, 3 and 5 cm H2O) were used to investigate the PEEP level on CO2 rebreathing. Flow and CO2% were constantly recorded with computer data acquisition and analysis system (Microcal Origin).

RESULTS

In conventional set-up, there was obvious CO2 rebreathing (rebreathing volume: 83.1 +/- 32.9 ml). In modified connection, the rebreathing volume was only (0.1 +/- 0.4) ml (P < 0.001).

CONCLUSION

There was obvious CO2 rebreathing during full face mask NIPPV in conventional set-up. A modified two ways connection could reduce CO2 rebreathing to be near zero, which might be important in the management of hypercapnic respiratory failure with NIPPV.

Role of STAT4 and STAT6 signaling in allograft rejection and CTLA4-Ig-mediated tolerance

STAT4(-/-) mice have impaired type 1 T cell differentiation, whereas STAT6(-/-) mice fail to generate type 2 responses. The role of type 1 and type 2 T cell differentiation in acute cardiac allograft rejection and in the induction of tolerance was examined in wild-type, STAT4(-/-), and STAT6(-/-) recipients. All recipients rejected the grafts promptly. Analysis of in situ cytokine gene expression in the allografts confirmed decreased levels of IFN-gamma in STAT4(-/-) recipients and undetectable levels of IL-4 and IL-5 in STAT6(-/-) mice. Blockade of the CD28/B7 costimulatory pathway prolonged cardiac graft survival for >100 days in 100% of wild-type and STAT4(-/-) mice. However, 14% of CTLA4-Ig-treated STAT6(-/-) mice rejected their grafts between 20 and 100 days. Moreover, of those animals followed past 100 days, 60% of the STAT6(-/-) mice rejected their grafts. Splenocytes harvested on day 145 posttransplant from CTLA4-Ig-treated rejecting STAT6(-/-) recipients were transfused into syngeneic SCID mice transplanted with donor or third party cardiac allografts. Both donor and third party grafts were rejected, indicating that the initial graft loss may be due to an immunological rejection. In contrast, when splenocytes from CTLA4-Ig-treated wild-type or nonrejecting STAT6(-/-) mice were transferred into SCID recipients, donor allografts were accepted, but third party hearts were rejected. Thus, long-term prolongation of cardiac allograft survival by CTLA4-Ig is STAT4-independent but, at least in part, STAT6-dependent. These data suggest that the balance of type 1 and type 2 T lymphocyte differentiation is not critical for acute rejection but influences the robust tolerance induced by CD28/B7 blockade in this model.

Regulation of plasminogen activitor inhibitor-1 in human adipose tissue: interaction between cytokines, cortisol and estrogen

To investigate further the role of plasminogen activator inhibitor-1 (PAI-1) in human adipose tissue, the regulation of cytokines, cortisol (dexamethasone) as well as estrogen on PAI-1 were determined in human adipose tissue fragments. PAI-1 activity was increased in human adipose tissue fragments incubated for 48 h with interleukin-1beta (IL-1beta) (2.6-fold, p < 0.01) and tumor necrosis factor-alpha (2.3-fold, p < 0.01). Incubation with interleukin-6 revealed a non-significant decrease in PAI-1 activity. Parallel findings were obtained when studying the PAI-1 mRNA expression. Dexamethesone increased PAI-1 activity after incubation for 8 h (p < 0.05) and enhanced the stimulation of IL-1beta after 8 h incubation. However, after 24 and 48 h, dexamethasone significantly reduced the IL-1beta induced increase in PAI-1 activity by 24-52% (p < 0.05), accordingly, PAI-1 mRNA expression was reduced 60%. Finally, the induction of PAI-1 activity and PAI-1 mRNA expression by IL-1beta was attenuated by estrogen (17.8+/-4.9%, p < 0.05 and 20.9+/-5.8%, p < 0.05, respectively). These results indicate that multiple cytokines, estrogen and dexamethasone may be involved in the regulation of PAI-1 biosynthesis in human adipose tissue, and suggest that there are interactions between cytokines and these steroid hormones. The interplay between these hormones may be of importance for the levels of PAI-1 observed in obesity and associated states.

[Clinical study of weaning predictors in COPD patients with prolonged mechanical ventilation]

OBJECTIVE

To evaluate the combined pulmonary function test at bedside as a predicting parameter of weaning in prolonged mechanically ventilated (MV) patients with chronic obstructive pulmonary disease (COPD).

METHODS

58 patients [mean duration of MV (18.4 +/- 9.2) d] who were divided into two groups were enrolled in this study. Group I included 43 patients [male 30, female 13, mean age (65 +/- 12) y] were successful in weaning, group II included 15 patients [male 10, female 5, mean age (64 +/- 10) y] were failed. ABGs, APACHEII, pulmonary function test and respiratory mechanics were measured in both groups after 30 minutes stable spontaneous breathing.

RESULTS

There were no significant difference in ABGs, APACHEII, oxygenation index (OI), dynamic compliance (Cdyn) and airway resistance (Raw) between two groups (all P values > 0.05). There were significant differences in the following parameters between two groups: vital capacity/tidal volume (VC/VT, 2.10 +/- 0.20 vs. 1.30 +/- 0.20), maximal inspiratory pressure (Pimax), (-21 +/- 4) vs. (-13 +/- 3) cm H2O, rapid shallow breath index (RSBI), f/VT, (74 +/- 30) vs. (115 +/- 20) times.min-1.L-1, all P values < 0.05. By the use of VC/VT(> 1.8), Pimax(< -18 cm H2O) and f/VT(< 105 times.min-1.L-1) as the criteria of weaning, the specificity (90%) was significantly higher than each of the above three parameters.

CONCLUSION

The bedside combined pulmonary function test (VC/VT, Pimax and f/VT) was a valuable weaning predictor in prolonged mechanically ventilated COPD patients.

[Study on clinical and laboratory features of preleukemia patients]

OBJECTIVE

To explore prospective diagnostic criteria for preleukemia.

METHODS

A case control study of the discrepancies of clinical and laboratory features between patients with preleukemia and those with chronic aplastic anemia (CAA) or atypical paroxysmal nocturnal hemoglubinuria (a-PNH).

RESULTS

There were eight variables of significance: (1) lymphocytoid micromegakaryocytes in marrow; (2) immature granulocytes in peripheral blood; (3) >or= 2% myeloblasts in marrow; (4) positive periodic acid schiff (PAS) staining of nucleated erythrocytes; (5) myeloid differentiation index >or= 1.8; (6) clonal karyotypic abnormalities; (7) negative sister chromatid differentiation; (8) > 4.0 cluster/colony ratio of granulocyte-macrophage colony-forming units (CFU-GM). The following criteria was assigned: A: To meet (1) and at least two of the other seven variables; B: To meet at least four of the eight variables. All of the patients with preleukemia met A or B and none of the patients with CAA or a-PNH did.

CONCLUSION

Preleukemia is different from CAA or a-PNH. It has its own clinical and laboratory features, which may be useful for prospective diagnosis.

Absence of host B7 expression is sufficient for long-term murine vascularized heart allograft survival

CD28 antagonists have been shown to promote long-term graft survival and induce donor-specific tolerance. In this study, the role of CD28/B7 costimulation and the relative importance of host versus donor B7 expression in allograft rejection was assessed in a murine abdominal vascularized heterotopic heart transplant model. Wild-type, CD28-deficient, or B7-1/B7-2-deficient C57BL/6 (B6) mice were grafted with allogeneic wild type or B7-1/B7-2-deficient hearts. The results demonstrate allogeneic heart grafts survive long-term in mCTLA4Ig-treated B6 and untreated B7-1/B7-2-deficient B6 recipients but not CD28KO B6 mice. B7-1/B7-2KO B6 recipients treated with anti-CD28 (PV-1) or recombinant human IL-2 rejected the heart transplants indicating that these mice are immunologically competent to reject grafts if costimulatory signals are supplied or bypassed. Finally, there was no difference in rejection between normal animals transplanted with wild-type versus B7-1/B7-2-deficient hearts. These results support a critical role for B7-expressing host antigen presenting cells in the rejection of heart allografts in mice and differences among B7KO and CD28KO animals.

Clinical pharmacokinetics of the prodrug oseltamivir and its active metabolite Ro 64-0802

Oseltamivir is an ethyl ester prodrug of Ro 64-0802, a selective inhibitor of influenza virus neuraminidase. Oral administration of oseltamivir delivers the active antiviral Ro 64-0802 to the bloodstream, and thus all sites of influenza infection (lung, nasal mucosa, middle ear) are accessible. The pharmacokinetic profile of oseltamivir is simple and predictable, and twice daily treatment results in effective antiviral plasma concentrations over the entire administration interval. After oral administration, oseltamivir is readily absorbed from the gastrointestinal tract and extensively converted to the active metabolite. The absolute bioavailability of the active metabolite from orally administered oseltamivir is 80%. The active metabolite is detectable in plasma within 30 minutes and reaches maximal concentrations after 3 to 4 hours. After peak plasma concentrations are attained, the concentration of the active metabolite declines with an apparent half-life of 6 to 10 hours. Oseltamivir is eliminated primarily by conversion to and renal excretion of the active metabolite. Renal clearance of both compounds exceeds glomerular filtration rate, indicating that renal tubular secretion contributes to their elimination via the anionic pathway. Neither compound interacts with cytochrome P450 mixed-function oxidases or glucuronosyltransferases. The pharmacokinetic profile of the active metabolite is linear and dose-proportional, with less than 2-fold accumulation over a dosage range of oseltamivir 50 to 500 mg twice daily. Steady-state plasma concentrations are achieved within 3 days of twice daily administration, and at a dosage of 75mg twice daily the steady-state plasma trough concentrations of active metabolite remain above the minimum inhibitory concentration for all influenza strains tested. Exposure to the active metabolite at steady state is approximately 25% higher in elderly compared with young individuals; however, no dosage adjustment is necessary. In patients with renal impairment, metabolite clearance decreases linearly with creatinine clearance. A dosage reduction to 75mg once daily is recommended for patients with creatinine clearance <30 ml/min (1.8 L/h). The pharmacokinetics in patients with influenza are qualitatively similar to those in healthy young adults. In vitro and in vivo studies indicate no clinically significant drug interactions. Neither paracetamol (acetaminophen) nor cimetidine altered the pharmacokinetics of Ro 64-0802. Coadministration of probenecid resulted in a 2.5-fold increase in exposure to Ro 64-0802; however, this competition is unlikely to result in clinically relevant effects. These properties make oseltamivir a suitable candidate for use in the prevention and treatment of influenza.

Identification of two novel mutations in the hypoglycemic phenotype of very long chain acyl-CoA dehydrogenase deficiency

Very long chain acyl-CoA dehydrogenase (VLCAD) catalyzes the initial step of long chain fatty acid oxidation in the mitochondria. Patients with VLCAD deficiency have recently been observed with two clinical phenotypes. The cardiac form presents with an early onset cardiomyopathy and a high incidence of infant death, while the hypoglycemic form resembles medium chain acyl-CoA dehydrogenase (MCAD) manifesting with hypoketotic hypoglycemia. In our investigation on the molecular basis for these phenotypes, we identified two novel mutations in one VLCAD patient with the hypoglycemic form, a C953T (Pro318Leu) mutation in exon 10 resulting in a substitution of proline 318 by leucine on one allele, and a C1194A (Tyr398Stop) mutation in exon 12 which created a premature stop codon TAA on another allele. The Tyr398Stop mutation may result in a truncated protein or instable messenger RNA.

Cutting edge: blockade of the CD28/B7 costimulatory pathway inhibits intestinal allograft rejection mediated by CD4+ but not CD8+ T cells

The effect of blocking the CD28/B7 costimulatory pathway on intestinal allograft rejection was examined in mice. Murine CTLA4Ig failed to prevent the rejection of allografts transplanted into wild-type or CD4 knockout (KO) mice but did inhibit allograft rejection by CD8 KO recipients. This effect was associated with decreased intragraft mRNA for IFN-gamma and TNF-alpha and increased mRNA for IL-4 and IL-5. This altered pattern of cytokine production was not observed in allografts from murine CTLA4Ig-treated CD4 KO mice. These data demonstrate that blockade of the CD28/B7 pathway has different effects on intestinal allograft rejection mediated by CD4+ and CD8+ T cells and suggest that these T cell subsets have different costimulatory requirements in vivo. The results also suggest that the inhibition of CD4+ T cell-mediated allograft rejection by CTLA4Ig may be related to down-regulation of Th1 cytokines and/or up-regulation of Th2 cytokines.

Angiotensin II stimulates DNA and protein synthesis in vascular smooth muscle cells from human arteries: role of extracellular signal-regulated kinases

OBJECTIVE

This study investigates the growth effects and associated signaling pathways of angiotensin II (Ang II) in human vascular smooth muscle cells.

METHODS

Cultured vascular smooth muscle cells derived from resistance arteries (< 300 microm diameter) from subcutaneous gluteal biopsies of healthy subjects (n = 6) and human aortic vascular smooth muscle cells were used. Cells were studied between passages 3 and 6. Both 3H-thymidine and 3H-leucine incorporation were measured as indices of vascular smooth muscle cell hyperplasia (DNA synthesis) and cell hypertrophy (protein synthesis), respectively. Growth effects of Ang II (10(-12) - 10(-6) mol/l), in the absence and presence of 10(-5) mol/l losartan (AT1 antagonist) and PD123319 (AT2 antagonist), were determined. Ang II-induced effects were compared to those of endothelin-1. To determine whether extracellular signal-regulated kinase (ERK)-dependent pathways play a role in Ang II-mediated growth, cells were pretreated with the selective ERK kinase (MEK) inhibitor, PD98059 (10(-5) mol/l). ERK activation was determined by Western blot in the absence and presence of PD98059.

RESULTS

Ang II dose-dependently increased 3H-thymidine incorporation in cells from aorta (Emax = 276 +/- 10.4% of control) and resistance arteries (Emax = 284 +/- 5.1% of control). Ang II also stimulated 3H-leucine incorporation in cells from aorta (Emax = 162 +/- 11.6 of control) and resistance arteries (Emax 175 +/- 10% of control). Unlike Ang II, endothelin-1 failed to significantly alter cellular growth, except at high concentrations (> 10(-7) mol/l), where it had a weak stimulatory effect Losartan, but not PD123319, blocked Ang II-stimulated growth responses. Ang II significantly increased phosphorylation of ERK-1 and ERK-2, with maximum responses obtained at 5 min. PD98059 inhibited Ang II-stimulated ERK activity and abrogated agonist-induced DNA and protein synthesis. Losartan, but not PD123319 inhibited Ang II-induced phosphorylation of ERK-1 and ERK-2.

CONCLUSIONS

Ang II stimulates both hyperplasia and hypertrophy in vascular smooth muscle cells from human arteries. These growth effects are mediated via Ang II receptors of the AT1 subtype that are linked to ERK-dependent signaling pathways.