Evolution of CDC42, a putative virulence factor triggering meristematic growth in black yeasts

The cell division cycle gene (CDC42) controlling cellular polarization was studied in members of Chaetothyriales. Based on ribosomal genes, ancestral members of the order exhibit meristematic growth in view of their colonization of inert surfaces such as rock, whereas in derived members of the order the gene is a putative virulence factor involved in expression of the muriform cell, the invasive phase in human chromoblastomycosis. Specific primers were developed to amplify a portion of the gene of 32 members of the order with known position according to ribosomal phylogeny. Phylogeny of CDC42 proved to be very different. In all members of Chaetohyriales the protein sequence is highly conserved. In most species, distributed all over the phylogenetic tree, introns and 3^rd codon positions are also invariant. However, a number of species had paralogues with considerable deviation in non-coding exon positions, and synchronous variation in introns, although non-synonomous variation had remained very limited. In some strains both orthologues and paralogues were present. It is concluded that CDC42 does not show any orthologous evolution, and that its paralogues haves the same function but are structurally relaxed. The variation or absence thereof could not be linked to ecological changes, from rock-inhabiting to pathogenic life style. It is concluded that eventual pathogenicity in Chaetothyriales is not expressed at the DNA level in CDC42 evolution.

Confined propagation of covalent chemical reactions on single-walled carbon nanotubes

Covalent chemistry typically occurs randomly on the graphene lattice of a carbon nanotube because electrons are delocalized over thousands of atomic sites, and rapidly destroys the electrical and optical properties of the nanotube. Here we show that the Billups-Birch reductive alkylation, a variant of the nearly century-old Birch reduction, occurs on single-walled carbon nanotubes by defect activation and propagates exclusively from sp(3) defect sites, with an estimated probability more than 1,300 times higher than otherwise random bonding to the 'π-electron sea'. This mechanism quickly leads to confinement of the reaction fronts in the tubular direction. The confinement gives rise to a series of interesting phenomena, including clustered distributions of the functional groups and a constant propagation rate of 18 ± 6  nm per reaction cycle that allows straightforward control of the spatial pattern of functional groups on the nanometre length scale.

A random comparative study of terbinafine versus griseofulvin in patients with tinea capitis in Western China

OBJECTIVE

To compare the efficacy and safety of terbinafine with griseofulvin in the treatment of tinea capitis in Western China.

METHODS

Children (2-14 years of age) with clinically diagnosed and potassium hydroxide microscopy-confirmed tinea capitis were randomized into three groups: group GRI4 received 4 weeks of griseofulvin; group TBF2 received 2 weeks of terbinafine; and Group TBF4 received 4 weeks of terbinafine. Clinical and mycological evaluations were done in 0, 2, 4, and 8 weeks and 1 year after therapy started. The isolated pathogenic fungi were evaluated for in vitro susceptibility by detecting the minimal inhibitory concentration (MIC) against terbinafine, griseofulvin, itraconazole, and ketoconazole.

RESULTS

The clinical effectiveness rate of GRI4, TBF2, and TBF4 were 100% (95% CI-confidence interval: 82-100%), 96.3% (95% CI: 81-100%), and 100%(95% CI: 85-100%), respectively, at week 8 and 100% after 1 year for the 3 groups; clinical cure rates were 84.2%(95% CI: 77-99%), 85.2%(95% CI: 71-98%), and 78.3%(95% CI: 61-95%), respectively, at week 8 and 100% after 1 year for all agents; mycological cure rates were 100%(95% CI: 74-100%), 95.0%(95% CI: 74-100%), and 94.1%(95% CI: 50-93%) at week 8 and 100% after 1 year for the 3 groups. In vitro, all patient-derived cultures were sensitive to the four antifungal agents.

CONCLUSION

Data from the clinical trial and in vitro antifungal activity indicated that terbinafine is efficacious and well tolerated in the treatment for Trichophyton infections (T. violaceum; Arthroderma vanbreuseghemii; and T. tonsurans) of the scalp, i.e., a 2- to 4-week course of terbinafine is as effective as a 4-week course of griseofulvin; in fact, a 2-week course of terbinafine is sufficient. Terbinafine is an effective alternative to griseofulvin against tinea capitis of Trichophyton infections.

Magnetostatic interactions in antiferromagnetically coupled patterned media

In an array of closely spaced magnetic islands as in patterned media, magnetostatic interactions play a major role in widening the switching field distribution and reducing the thermal stability. Patterned antiferromagnetically coupled (AFC) media provide interesting systems for studying the effect of magnetostatic interactions on the reversal of closely spaced AFC bits in an array, as AFC structure helps to reduce the remanent magnetization (M(r)), leading to reduced magnetostatic interactions. Here, we study the magnetic reversal of single domain-patterned AFC CoCrPt:oxide bilayer system with perpendicular magnetic anisotropy, by imaging the remanence state of the bits after the application of a magnetic field with magnetic force microscopy (MFM). The influence of magnetostatic fields from the neighboring bits on the switching field distribution (SFD) for an entity in a patterned media is studied by varying the stabilizing layer thickness of the AFC structure and bit spacing. We observe a distinct increase in stability and coercivity with an increase in stabilizing layer thickness for the 40 nm spaced bits. This demonstrates the effectiveness of the AFC structure for reducing magnetostatic interactions in patterned media, such that high thermal stability can be achieved by the reduced M(r), without writability issues.

Phaeohyphomycosis caused by a plant pathogen, Corynespora cassiicola

We report a case of subcutaneous phaeohyphomycosis caused by Corynespora cassiicola. Molecular identification of this pathogen on grasses confirms that it may be involved in human infection, as previously reported once in pre-molecular literature. In vitro antifungal susceptibility data of the strain are provided. The patient was successfully treated with oral terbinafine with topical povidone iodine in accordance with the results obtained through in vitro susceptibility testing.

An unexpected counter-regulatory role of IL-10 in B-lymphocyte-mediated transplantation tolerance

Monoclonal antibody against the CD45RB protein induces stable transplantation tolerance to multiple types of allograft. We have previously established that this tolerance protocol relies on the regulatory function of B lymphocytes for its effect. B lymphocytes have also been reported to participate in immune regulation in several other settings. In most of these systems, the regulatory function of B lymphocytes depends on the production of IL-10. Therefore, we investigated the role of IL-10 in the anti-CD45RB model of B-cell-mediated transplantation tolerance. Surprisingly, using antibody-mediated neutralization of IL-10, IL-10-deficient recipients and adoptive transfer of IL-10-deficient B lymphocytes, we found that IL-10 actually counter-regulates tolerance induced by anti-CD45RB. Furthermore, neutralization of IL-10 reduced the development of chronic allograft vasculopathy compared to anti-CD45RB alone and reduced the production of graft reactive alloantibodies. These data suggest that the participation of regulatory B lymphocytes in transplantation tolerance may be distinct from how they operate in other systems. Identifying the specific B lymphocytes that mediate transplantation tolerance and defining their mechanism of action may yield new insights into the complex cellular network through which antigen-specific tolerance is established and maintained.

Research on HIV/Toxoplasma gondii co-infection and cytokine levels among intravenous drug users

HIV and T. gondii infection markers were measured among 383 Intravenous Drug Users (IDU). And cytokine concentrations (IL-4, IL-6, IL-10, IL-12, IFN-gamma and TNF-alpha) were determined. The results showed IDU with HIV infection or HIV/T. gondii co-infection could disturb Th regulatory mechanism.

An effective surface-enhanced Raman scattering template based on a Ag nanocluster-ZnO nanowire array

An effective surface-enhanced Raman scattering (SERS) template based on a 3D hybrid Ag nanocluster (NC)-decorated ZnO nanowire array was fabricated through a simple process of depositing Ag NCs on ZnO nanowire arrays. The effects of particle size and excitation energy on the Raman scattering in these hybrid systems have been investigated using rhodamine 6G as a standard analyte. The results indicate that the hybrid nanosystem with 150 nm Ag NCs produces a larger SERS enhancement factor of 3.2 x 10(8), which is much higher than that of 10 nm Ag NCs (6.0 x 10(6)) under 532 nm excitation energy. The hybrid nanowire arrays were further applied to obtain SERS spectra of the two-photon absorption (TPA) chromophore T7. Finite-difference time-domain simulations reveal the presence of an enhanced field associated with inter-wire plasmon coupling of the 150 nm Ag NCs on adjacent ZnO nanowires; such a field was absent in the case of the 10 nm Ag NC-coated ZnO nanowire. Such hybrid nanosystems could be used as SERS substrates more effectively than assembled Ag NC film due to the enhanced light-scattering local field and the inter-wire plasmon-enhanced electromagnetic field.

[Studies on allelic zymogram of periodic Brugia malayi from Zhejiang Province]

AIM

To study the allelic zymogram of periodic B. malayi from Zhejiang Province.

METHODS

180 adult worms(male 60, female 120), 32,000 microfilaria and 1,500 infective larvae of periodic B. malayi were examined for the isoenzymes of 14 enzymes by horizontal starch gel electrophoresis with 14 different isomyme.

RESULTS

Twenty-seven allelic loci were found in three developing stages of B. malayi, most of them were homozygotes, however, two of them(MPI,MDH) were heterozygotes(7.4%). 17, 19 and 9 loci were presented in adult worms, microfilariae and infective larvae, respectively. At the same time, the allelic zymogram of B. malayi from Guizhou Province was also examined.

CONCLUSION

The allelic zymogram of periodic B. malayi from Zhejiang Province was similar to that of periodic B. malayi from Guizhou Province but passaged in the laboratory.

[Effect of nitroquine on the membrane phospholipid of intraerythrocytic Plasmodium yoelii in vitro]

AIM

To study the mechanism of antimalarial action of nitroquine.

METHODS

Intraerythrocytic P. yoelii was cultured by the method of Trager and Jensen. The amount of [3H]-ethanolamine incorporation was measured as an index of the phospholipid synthesis. DPH was used as a probe to measure the plasmodial fluorescent polarization.

RESULTS

The incorporation of [3H]-ethanolamine into the P. yoelii infected erthrocytes was markedly inhibited by nitroquine. The plasmodial membrane polarization and viscosity were significantly increased by nitroquine.

CONCLUSION

Nitroquine could inhibit the phospholipid synthesis and decrease the membrane fluidity of P. yoelii.

Exendin-4 does not promote Beta-cell proliferation or survival during the early post-islet transplant period in mice

Current pancreatic islet transplantation protocols achieve remarkable short-term success, but long-term insulin independence remains elusive. Hypoxic and inflammatory insults cause substantial early posttransplant graft loss while allo/autoimmunity and immunosuppressive drug toxicity threaten long-term graft mass and function. Exendin-4 (Ex4) is a GLP-1 receptor agonist that promotes beta-cell proliferation, survival, and differentiation. To determine whether Ex-4 displays potential as a graft-supportive agent, we transplanted 500 murine islets under the kidney capsule of syngeneic or allogeneic streptozocin-treated recipient mice and immediately initiated daily treatment with vehicle or Ex4. Graft beta-cell proliferation, death, and vascularity were assessed at 1, 3, and 10 days after syngeneic islet transplantation. For allogeneic recipients, blood glucose and body weight were assessed until glycemic deterioration. Ex-4 did not promote graft beta-cell proliferation, reduce beta-cell death, or enhance graft vascularity over the first 10 days after syngeneic islet transplantation. A trend toward prolongation of posttransplant euglycemia was observed with Ex4 treatment in nonimmune-suppressed allograft recipients, but its use in this setting was associated with frequent, severe hypoglycemia over the first 2 posttransplant days. Our findings do not support a beneficial effect of Ex-4 on islet grafts during the critical early posttransplant period, further, they demonstrate a significant hypoglycemic potential of Ex-4 in the first days after islet transplantation in mice. Optimal application of GLP-1 receptor agonists for long-term proliferative and survival benefits in transplantation may require earlier intervention prior to and/or during islet isolation for peri-transplant cytoprotection and administration beyond the period of engraftment.

Hosing instability in the blow-out regime for plasma-wakefield acceleration

The electron hosing instability in the blow-out regime of plasma-wakefield acceleration is investigated using a linear perturbation theory about the electron blow-out trajectory in Lu et al. [in Phys. Rev. Lett. 96, 165002 (2006)10.1103/PhysRevLett.96.165002]. The growth of the instability is found to be affected by the beam parameters unlike in the standard theory Whittum et al. [Phys. Rev. Lett. 67, 991 (1991)10.1103/PhysRevLett.67.991] which is strictly valid for preformed channels. Particle-in-cell simulations agree with this new theory, which predicts less hosing growth than found by the hosing theory of Whittum et al.

Noni as an anxiolytic and sedative: a mechanism involving its gamma-aminobutyric acidergic effects

Noni (Morinda citrifolia) is increasing in worldwide popularity as a food or dietary supplement with versatile health benefits. The aim of this study was to investigate the effects of Noni fruit on anxiety symptoms in vitro. To this end, a competitive GABAa receptor-binding assay was developed. Our preliminary study indicates that the methanol crude extract of Noni fruit showed significant affinity to the gamma-aminobutyric acid A (GABAa) inhibitory neurotransmitter receptors, and displayed 75% binding inhibition of the agonist radioligand [3H] muscimol at a concentration of 100 microg/ml. Further experiments demonstrated that the MeOH extract, and its BuOH and H2O partitions, exhibited IC50 values of 22.8, 27.2, and 17.1 microg/ml, respectively, in the GABAa-binding assay. Experimental results with Noni fruit indicate the presence of competitive ligand(s), which may bind to the GABAa receptor as an agonist, and thus induce its anxiolytic and sedative effects. The study provides an in vitro rationale for one of Noni's versatile and traditional uses. In addition, an HPLC fingerprint profile of the methanolic extract of Noni fruit has been established for quality control purpose.

Ionization-induced electron trapping in ultrarelativistic plasma wakes

The onset of trapping of electrons born inside a highly relativistic, 3D beam-driven plasma wake is investigated. Trapping occurs in the transition regions of a Li plasma confined by He gas. Li plasma electrons support the wake, and higher ionization potential He atoms are ionized as the beam is focused by Li ions and can be trapped. As the wake amplitude is increased, the onset of trapping is observed. Some electrons gain up to 7.6 GeV in a 30.5 cm plasma. The experimentally inferred trapping threshold is at a wake amplitude of 36 GV/m, in good agreement with an analytical model and PIC simulations.

Removal of As(V) and As(III) from water with a PEI-modified fungal biomass

A novel biosorbent was prepared by chemically grafting polyethylenimine (PEI) on the fungal biomass of Penicillium chrysogenum through a two-step reaction. The PEI-modified biomass was found to possess zero zeta potential at pH 10.4. Owing to the protonation of amine groups on the biosorbent surface, the biosorbent is favourable for the removal of anionic arsenic species in water. The sorption capacity for As(V) at pH 3 increased by 5.7-fold after surface modification. The sorption performances including kinetics and isotherm were investigated and several models were used to describe the experimental data. The pseudo-second-order model described the kinetic data better, while the Langmuir equation was the better model to fit the isotherm data. The corresponding thermodynamic parameters for As(V) and As(III) sorption were also calculated.

Positron production by x rays emitted by betatron motion in a plasma wiggler

Positrons in the energy range of 3-30 MeV, produced by x rays emitted by betatron motion in a plasma wiggler of 28.5 GeV electrons from the SLAC accelerator, have been measured. The extremely high-strength plasma wiggler is an ion column induced by the electron beam as it propagates through and ionizes dense lithium vapor. X rays in the range of 1-50 MeV in a forward cone angle of 0.1 mrad collide with a 1.7 mm thick tungsten target to produce electron-positron pairs. The positron spectra are found to be strongly influenced by the plasma density and length as well as the electron bunch length. By characterizing the beam propagation in the ion column these influences are quantified and result in excellent agreement between the measured and calculated positron spectra.

Hose instability and wake generation by an intense electron beam in a self-ionized gas

The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with this slower growth instability depending on the radius of the ionization channel compared to the electron blowout radius. A new regime for hose stable plasma wakefield acceleration is suggested.

Chromate sorption and reduction kinetics onto an aminated biosorbent

A novel biosorbent was prepared by chemically grafting of polyethylenimine (PEI) onto the fungal biomass of Penicillium chrysogenum through a two-step reaction. The modified biosorbent is favorable for the removal of anionic Cr(VI) species from aqueous solution due to the protonation of amine groups on the biomass surface. The sorption capacity for Cr(VI) increased by 7.2-fold after surface modification. Sorption kinetics results show that the pseudo-second-order kinetic model described the experimental data well. During the sorption process, X-ray photoelectron spectroscopy (XPS) was used to analyze the chromium species on the biosorbent surface and the results indicate that part of the Cr(VI) ions were reduced to Cr(III) ions which can be chelated with the amine groups on the biomass surface. The reduced Cr(III) ions formed some aggregates on the surface at higher solution pHs.

Psychological symptoms and nonfatal unintentional injuries among Chinese adolescents: a prospective study

PURPOSE

To describe patterns of nonfatal unintentional injuries and investigate the association of psychological symptoms with injury risk among adolescents in Guangxi, China.

METHODS

Adolescents were selected from middle and high school students in Baise City, Guangxi, China. Psychological symptoms at baseline were measured using SCL-90-R and nonfatal unintentional injuries that occurred among participants were recorded using a standardized injury surveillance questionnaire. Annual injury rates per 100 adolescents by adolescents' demographic and family characteristics were calculated. Student's t-test and the Chi-square test were used to test differences in mean raw scores of SCL-90-R subscales and injury rates. Relative risks and odds ratios of injury with 95% confidence intervals were calculated in univariate analyses and multivariate logistic models.

RESULTS

A total of 1474 middle and high school students finished the study. Of them, 442 reported nonfatal unintentional injuries during the study period, resulting in an annual injury rate of 30.3 per 100 adolescents. Boys had a significantly higher injury rate than girls (32.6% vs. 27.4%). Injury rate decreased as the adolescents' age increased. Compared with adolescents who were not injured, the injured adolescents had higher average raw scores of all subscales of SCL-90-R, with an exception of the subscale for hostility. All SCL-90-R subscales factors, except those for hostility and phobia, were associated with injury risk. After confounding effects of age, gender, and ethnicity were controlled using logistic regression models, SCL-90-R subscales for somatization (OR = 2.00, 95% CI 1.52-2.63), obsessive-compulsiveness (OR = 2.10, 95% CI 1.71-2.58), interpersonal-sensitivity (OR = 1.66, 95% CI 1.34-2.06), depression (OR = 2.00, 95% CI 1.59-2.51), anxiety (OR = 2.08, 95% CI 1.62-2.66), and psychoticism (OR = 1.60, 95% CI 1.26-2.03) were significantly associated with an elevated injury risk.

CONCLUSION

Psychological symptoms are associated with an elevated risk of nonfatal unintentional injury among middle and high school students. Mental health services, such as psychological counseling, may help reduce the risk of nonfatal unintentional injuries among Chinese adolescents.

Development of anti-human leukocyte antigen class 1 antibodies following allogeneic islet cell transplantation

Currently there is minimal concern that islet allograft failure could result from the development of anti-human leukocyte antigen (HLA) antibodies reactive to the allograft. We report here a case of islet allograft failure where the recipient developed immunoglobulin G anti-HLA class I antibodies reactive to HLA antigens present in two of the three islet cell donors. The patient had no detectable anti-HLA antibodies prior to the transplant but these antibodies were detected approximately 4 months posttransplant. Of concern, these antibodies developed despite induction with anti-IL2R antibodies (Zenapex) prior to intraportal islet cell infusion, low-dose tacrolimus (12-hour troughs 3 to 5 ng/mL) and rapammune (target troughs 12 to 15 ng/mL). The patient was not presensitized with blood products or a previous allograft. Her husband, however, shared antigens present in one of the islet donors and the recipient could have been presensitized to her husband during her two pregnancies. This case clearly demonstrates that islet allografts can lead to development of anti-HLA antibodies, which can cause islet allograft failure, as is the case with solid organ transplants, and hence emphasizes the need to monitor for such antibodies pre- and posttransplant. Additionally it appears that currently recommended immunosuppression may not be sufficient to inhibit a humoral response to both alloantigens and autoantigens.

Multi-GeV energy gain in a plasma-wakefield accelerator

A plasma-wakefield accelerator has accelerated particles by over 2.7 GeV in a 10 cm long plasma module. A 28.5 GeV electron beam with 1.8 x 10(10) electrons is compressed to 20 microm longitudinally and focused to a transverse spot size of 10 microm at the entrance of a 10 cm long column of lithium vapor with density 2.8 x 10(17) atoms/cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons. These electrons return one-half plasma period later driving a large amplitude plasma wake that in turn accelerates particles in the back of the bunch by more than 2.7 GeV.

Synthesis and evaluation of fluorine-18 labeled glyburide analogs as beta-cell imaging agents

Glyburide is a prescribed hypoglycemic drug for the treatment of type 2 diabetic patients. We have synthesized two of its analogs, namely N-[4-[beta-(2-(2'-fluoroethoxy)-5-chlorobenzenecarboxamido)ethyl]benzenesulfonyl]-N'-cyclohexylurea (2-fluoroethoxyglyburide, 8b) and N-[4-[beta-(2-(2'-fluoroethoxy)-5-iodobenzenecarboxamido)ethyl]benzenesulfonyl]-N'-cyclohexylurea (2-fluoroethoxy-5-deschloro-5-iodoglyburide, 8a), and their fluorine-18 labeled analogs as beta-cell imaging agents. Both F-18 labeled compound 8a and compound 8b were synthesized by alkylation of the corresponding multistep synthesized hydroxy precursor 4a and 4b with 2-[(18)F]fluoroethyl tosylate in DMSO at 120 degrees C for 20 minutes followed by HPLC purification in an overall radiochemical yield of 5-10% with a synthesis time of 100 minutes from EOB. The octanol/water partition coefficients of compounds 8a and 8b were 141.21 +/- 27.77 (n = 8) and 124.33 +/- 21.61 (n = 8), respectively. Insulin secretion experiments of compounds 8a and 8b on rat islets showed that both compounds have a similar stimulating effect on insulin secretion as that of glyburide. In vitro binding studies showed that approximately 2% of compounds 8a and 8b bound to beta TC3 and Min6 cells and that the binding was saturable. Preliminary biodistribution studies in mice showed that the uptake of both compounds 8a and 8b in liver and small intestine were high, whereas the uptake in other organs studied including pancreas were low. Additionally, the uptake of compound 8b in vivo was nonsaturable. These results tend to suggest that compounds 8a and 8b may not be the ideal beta-cell imaging agents.

A new technology for mutation detection

A sensitive, accurate, and simple method, called shifted termination assay (STA), was developed for detection of genetic mutations. The STA technology can be used to detect genetic mutations in polymerase chain reaction (PCR)-amplified samples of tissue, and plasma and serum that include circulating DNA containing point mutations, insertions, deletions, translocations, or single nucleotide polymorphisms (SNPs). STA is a multiple-base and multiple-cycle primer extension based detection method that can identify mutant DNA in samples containing as little as 1% mutant DNA in a mixture with 99% wild-type DNA. On the basis of the STA method, a mutation detection kit, called Mutector, was developed. Mutector is a 96-well microplate format test kit with colorimetric or luminescent detection options. An initial study shows that Mutector is more accurate and sensitive than sequencing and PCR restriction enzyme analysis methods in detecting DNA mutations from clinical samples.

Assessment of human pancreatic islets after long distance transportation

Pancreatic islet transplantation can replace functional insulin-secreting beta cells for patients with type 1 diabetes. More than 300 patients who have received islet transplantation have returned to a euglycemic condition without using insulin. Therefore, islet transplantation has gained public attention and interest. Unfortunately, shortages in organ donations, suboptional antirejection regimens, and difficulties in islet isolation limit clinical utilization of this therapy. Recently, successful islet transplantation has been reported using a centralized islet isolation facility. The advantage of this experience is that it avoids the high costs in building an isolation facility and maintaining an experienced technical team. However, a private airplane carrier was required for transporting islets back to the transplantation site in a remote hospital. The cost of this specialized transportation was still too high to be considered as a routine procedure. In this study, we report our experience using commercial carriers to deliver isolated human islets from an established isolation facility to a remote medical center.

Distribution and shifting trends of bacterial keratitis in north China (1989-98)

AIMS

To study the distribution and shifting trends of bacterial keratitis.

METHODS

The data of 2220 corneal isolates from 1 January 1989 to 31 December 1998 were reviewed retrospectively.

RESULTS

Positive culture was recovered in 490 isolates. Gram positive cocci and Gram negative bacilli represented 51% and 39.4%, respectively. Pseudomonas aeruginosa was the most common pathogen (32.2%). A gradual increase in the percentage of Gram positive cocci coupled with a decrease of Gram negative bacilli.

CONCLUSION

Pseudomonas aeruginosa and coaculase negative Staphylococcus were the most common pathogens in bacterial keratitis in north China.

Isolation of linoleic acid as an estrogenic compound from the fruits of Vitex agnus-castus L. (chaste-berry)

A methanol extract of chaste-tree berry (Vitex agnus-castus L.) was tested for its ability to displace radiolabeled estradiol from the binding site of estrogen receptors alpha (ERalpha) and beta (ERbeta). The extract at 46 +/- 3 microg/ml displaced 50% of estradiol from ERalpha and 64 +/- 4 microg/ml from ERbeta. Treatment of the ER+ hormone-dependent T47D:A18 breast cancer cell line with the extract induced up-regulation of ERbeta mRNA. Progesterone receptor (PR) mRNA was upregulated in the Ishikawa endometrial cancer cell line. However, chaste-tree berry extract did not induce estrogen-dependent alkaline phosphatase (AP) activity in Ishikawa cells. Bioassay-guided isolation, utilizing ER binding as a monitor, resulted in the isolation of linoleic acid as one possible estrogenic component of the extract. The use of pulsed ultrafiltration liquid chromatography-mass spectrometry, which is an affinity-based screening technique, also identified linoleic acid as an ER ligand based on its selective affinity, molecular weight, and retention time. Linoleic acid also stimulated mRNA ERbeta expression in T47D:A18 cells, PR expression in Ishikawa cells, but not AP activity in Ishikawa cells. These data suggest that linoleic acid from the fruits of Vitex agnus-castus can bind to estrogen receptors and induce certain estrogen inducible genes.

Plasma wakefield acceleration in self-ionized gas or plasmas

Tunnel ionizing neutral gas with the self-field of a charged particle beam is explored as a possible way of creating plasma sources for a plasma wakefield accelerator [Bruhwiler et al., Phys. Plasmas (to be published)]. The optimal gas density for maximizing the plasma wakefield without preionized plasma is studied using the PIC simulation code OSIRIS [R. Hemker et al., in Proceeding of the Fifth IEEE Particle Accelerator Conference (IEEE, 1999), pp. 3672-3674]. To obtain wakefields comparable to the optimal preionized case, the gas density needs to be seven times higher than the plasma density in a typical preionized case. A physical explanation is given.

Insulin gene transfer enhances the function of human islet grafts

AIMS/HYPOTHESIS

Recent success in islet transplantation renews the hope for the complete cure of patients afflicted with Type 1 diabetes. However, in the Edmonton series, two to four pancreas donors were required to obtain a sufficient islet mass to reverse the diabetes of each patient. In view of the donor shortage, this represents a major obstacle preventing greater application of islet transplantation to diabetic patients. We hypothesised that increasing the expression of the insulin gene in transplanted islets would augment their capacity for insulin production, thereby allowing reversal of diabetes with a reduced islet mass.

METHODS

We used a replication defective adenovirus to deliver the human proinsulin gene (Ad-Ins) to isolated human islets. The function of Ad-Ins-transduced human islets was compared to islets transduced with a control vector (Ad-lacz).

RESULTS

Ad-Ins-transduced islets produced two to three times more insulin than normal islets or those infected with Ad-lacz, as assessed by in vitro perifusion tests of glucose stimulated insulin release. When transplanted, Ad-Ins-transduced islets normalised the blood glucose of diabetic immunodeficient NOD-Scid mice, and less than half as many Ad-Ins islets were required for reversal of diabetes than when normal islets were transplanted.

CONCLUSION/INTERPRETATION

Our results suggest a simple and effective approach that could enhance the efficiency of islet transplantation for treatment of diabetes in humans.

[Indirect determination of berberine hydrochloride by atomic absorption spectrometry]

A method for the indirect determination of berberine in tabellae berberine hydrochloride by ion pair extraction and atomic absorption spectrometry was described. Berberine reacted with inorganic complex tetrathiocyanate cobalt(II) to form a stable ion pair associated complex at certain pH value. The ion pair associated complex was extracted with organic solvent and then transferred into aqueous solution. The content of cobalt in the solution was measured by flame atomic absorption spectrometry and the amount of berberine hydrochloride was calculated according to the content of cobalt. The result of the present method agreed with pharmacopeia method. This method is sensitive, dependable, precise, and applicable.

Clinical applications of plasma shock wave lithotripsy in treating postoperative remnant stones impacted in the extra- and intrahepatic bile ducts

BACKGROUND

Choledochofiberscopy with basket extraction has been used widely to treat postoperative remnant stones in the bile duct system. However, it remains difficult to extract stones impacted in the bile duct system or stones too large to pass through the T-tube fistula. This report describes the efficacy and safety of plasma shock wave lithotripsy (PSWL) in fragmenting and eliminating such remnant stones from the bile duct.

METHODS

In 52 patients, 117 remnant stones were fragmented with PSWL and subsequently extracted with choledochofiberscopy. The efficacy and safety of PSWL were observed during and after the procedure.

RESULTS

After 116 of 117 remnant stones (99.1%) impacted in the extra- and intrahepatic bile ducts were fragmented successfulIy with PSWL, they were extracted with choledochofiberscopy. There were no significant complications during and after the procedure.

CONCLUSION

It appears that PSWL is an effective and safe method for fragmenting remnant stones impacted in the bile duct system and stones too large to pass through the T-tube fistula.

A cyclin-dependent kinase inhibitor (p21(WAF1/CIP1)) affects thymidine incorporation in human liver cancer cells

p21(WAF1/CIP1) is a universal cyclin-dependent kinase inhibitor. To investigate the role of p21(WAF1/CIP1) in proliferation of human liver cancer cells, we examined the expression of p53, p21(WAF1/CIP1), cdk2 and cdk4 expression in two human liver cancer cell lines (HepG2 and PLC/PRF/5 cells). The effects of p21(WAF1/CIP1) on [(3)H]thymidine incorporation and cdks were also examined in these cells. HepG2 cells expressed all these proteins with lower level of cdk4. PLC/PRF/5 cells expressed the other proteins except p21(WAF1/CIP1). Transfection of p21(WAF1/CIP1) gene inhibited [(3)H]thymidine incorporation of both cells with different extent. Although the transfection of p21(WAF1/CIP1) did not affect cdk2 and cdk4 expression, it did reduce cdk2 kinase activity by 20%. These results suggest that: (a) p21(WAF1/CIP1) involved in DNA synthesis of human liver cancer cells; (b) p21(WAF1/CIP1) could be a target gene for the treatment of human hepatocellular carcinoma.

Adult porcine islet transplantation in baboons treated with conventional immunosuppression or a non-myeloablative regimen and CD154 blockade

The aim of the present study was to assess the survival of adult porcine islets transplanted into baboons receiving either (I) conventional triple drug immunosuppressive therapy or (2) a non-myeloablative regimen and an anti-CD154 monoclonal antibody (mAb) aimed at tolerance-induction. Group 1 baboons (n = 3) were pancreatectomized prior to intraportal injection of 10,000 porcine islet equivalents (IE)/kg and immunosuppressed with anti-thymocyte globulin (ATG), cyclosporine and azathioprine. In Group 2 (n = 2), non-pancreatectomized baboons underwent induction therapy with whole body and thymic irradiation, and ATG. Extracorporeal immunoadsorption (EIA) of anti-Galalpha1,3Gal (Gal) antibody was carried out. Maintenance therapy was with cobra venom factor, cyclosporine. mycophenolate mofetil, methylprednisolone and anti-CD154 mAb. Porcine islets were injected intraportally (14,000 and 32,000 IE/kg, respectively) and high-dose pig mobilized peripheral blood progenitor cells (3 x 10(10) cells/kg) were infused into a systemic vein. Porcine islets were also implanted in the sternomastoid muscle to facilitate subsequent biopsies. In both groups. porcine C-peptide was measured, and histological examination of liver or sternomastoid muscle biopsies was performed at regular intervals. In Group 1, total pancreatectomy reduccd human C-peptide to < 0.1 ng/ml and induced insulin-requiring diabetes. The transplantation of porcine islets was followed by normalization of glycemia for 15-24 h. Porcine C-peptide was detected only transiently immediately after porcine islet injection (maximum 0.12 ng/ml). Histological examination of liver biopsies taken between days 2 and 19 did not reveal viable islets, but necrotic cell structures with mononuclear cell infiltrates were identified in portal venules. In Group 2, injection of porcine islets into non-pancreatectomized recipients induced a transient hypoglycemia (2-4 h) requiring concentrated intravenous dextrose administration. Porcine C-peptide was detectable for 5 and 3 days (maximum 2.8 and 1.0 ng/ml), respectively. Baboon #4 died on day 12 from small bowel intussusception. Liver and sternomastoid muscle biopsies showed well-preserved porcine islets, staining positive for insulin and glucacon, without signs of rejection. In baboon #5, viable islets were detected in the sternomastoid muscle biopsy on day 14, but not on day 28 or thereafter. A progressive mononuclear cell and macrophage infiltration was seen in the biopsies. In conclusion, conventional immunosuppression allowed survival of porcine islets in baboons for < 24 h. The non-myeloablative regimen prolonged survival of porcine islets for > 14 days. However, despite depletion of T cells, anti-Gal antibody and complement, and CD154-hlockade, porcine islets were rejected by day 28. These results suggest that powerful innate immune responses are involved in rejection of discordant xenogencic islets.

Leptin and obesity in mother-child pairs

Defects in the leptin gene or the leptin receptor may be a genetic cause of obesity, but little is known about the familial associations of leptin and obesity. This study compared plasma leptin and measures of obesity in a sample of 248 subjects (124 mother-offspring pairs); 34% were African American and 66% were white. Youth were aged 12 to 16 years. Plasma leptin and body mass index (BMI) were higher in mothers than in their offspring and, among the offspring, higher in girls than boys, even after correcting for BMI or body fat. Racial differences in leptin were present in both mothers and youth when adjusting for percentage body fat but disappeared when adjusting for BMI. In univariate analyses of the associations between mothers and offspring, BMI was associated with leptin in all groups but was most strongly associated in white pairs and in mother-son pairs. In multiple regression analyses, when adjusting for BMI, significant predictors of leptin levelfor the boys and girls together were gender, BMI, and pubertal status of the offspring; in girls only BMI was significant (R2 = 0.72), and in boys the significant predictors were their BMI (R2 = 0.66) followed by their pubertal status (R2 = 0.06) and the leptin level of their mothers (R2 = 0.02). When adjusting for body fat, the predictors were the offspring's percentage bodyfat (R2 = 0. 67) and mother's leptin (R2 = 0.03), with similar results in gender-specific analyses. The authors conclude that leptin levels of youth are most closely associated with their degree of obesity or body fat; mother's leptin and, for boys only, pubertal status also play a small role. Although the small association between maternal leptin on leptin in their offspring could be due to either heredity or shared environment, the results of this study suggest that individual obesity and environmental factors are important predictors of leptin levels in children.

Cloning and characterization of a second acid phosphatase from Sinorhizobium meliloti strain 104A14

Sinorhizobium meliloti has two nonspecific periplasmic acid phosphatases. The NapD enzyme has been previously described, and a second acid phosphatase, NapE, is described in this report. NapE was partially purified from an S. meliloti napD mutant and characterized with respect to molecular mass and substrate range. As predicted from SDS-PAGE analysis, the subunit molecular mass of NapE is approximately 35.8 kDa and gel filtration experiments estimated the native molecular mass to be approximately 70 kDa, indicating that the active enzyme is a homodimer. NapE demonstrated significant activity with p-nitrophenyl phosphate, phenyl phosphate, and alpha-naphthyl-phosphate. The pH optimum was between 4.5 and 5.0. The gene encoding NapE was also sequenced and the inferred amino acid sequence from the predicted ORF was found to be 60% identical and 75% similar to that encoded by napD. An S. meliloti napE mutant was constructed and assessed for symbiotic competence. This mutant did not differ from the wild-type parent strain in nodulation and symbiotic efficiency.

[The influence of recombinant human growth hormone on the metabolism of glucose and protein in severely burned patients]

OBJECTIVE

To investigate the influence of recombinant human growth hormone (rhGH) on the metabolism of glucose and protein in severely burned patients.

METHODS

The serum levels of total protein and albumin and the incidence of hyperglycemia in 24 cases of severely burned patients treated by rhGH were determined and compared with those in patients without rhGH treatment (control group).

RESULTS

The serum levels of total protein (TP) and albumin in burned patients after being treated by rhGH were much higher than those before treatment and those in control group. The blood level of glucose increased within 2 weeks, especially 1 week postburn. The incidences of hyperglycemia were 52.38%, 50.24% and 20% on 0 similar 3, 4 similar 7 and 8 similar 14 postburn days (PBDs), respectively. And the incidences of hyperglycemia were 100%, 50% and 0% when the administration of rhGH started within 1, 2 and after 2 weeks respectively.

CONCLUSION

The systemic protein synthesis in severely burned patients could be accelerated by the use of rhGH. But early administration of rhGH in burned patients could affect blood sugar level obviously. And the optimal time to give rhGH is 2 weeks after burn injury.