High strain rate testing of bovine trabecular bone

In spinal vertebral burst fractures, the dynamic properties of the trabecular centrum, which is the central region of porous bone inside the vertebra, can play an important role in determining the failure mode. If the failure occurs in the posterior portion of the vertebral body, spinal canal occlusion can occur and ejected trabecular bone can impact the spinal cord resulting in serious injury. About 15% of all spinal cord injuries are caused by such burst fractures. Unfortunately, due to the uniqueness of burst fracture injuries, postinjury investigation cannot always accurately assess the degree of damage caused by these fractures. This research makes an effort to begin understanding the governing effects in this important bone fracture event. Measurements of the dynamic deformation response of bovine trabecular bone with the marrow intact and marrow removed using a modified split-Hopkinson pressure bar apparatus are reported and compared with quasistatic deformation response results. Because trabecular bone is more compliant and lower in strength than cortical bone, typical Hopkinson pressure bar experimental techniques used for high strain rate testing of harder materials cannot be applied. Instead, a quartz-crystal-embedded, split-Hopkinson pressure bar developed for testing compliant, low strength materials is used. Care is taken into account for the orthotropic properties in the bone by testing only along the principle material axes, determined through microcomputed tomography. In addition, shaping of the stress wave pulse is used to ensure a constant strain rate and homogeneous specimen deformation. Results indicate that the strength of trabecular bone increases by a factor of approximately 2-3 when the strain rate increases from 10(-3) s(-1) to 500 s(-1) and that the bone fractures beyond a critical strain.

Efficacy and safety of losartan in treatment of hyperuricemia and posttransplantation erythrocytosis: results of a prospective, open, randomized, case-control study

BACKGROUND

Hyperuricemia and posttransplantation erythrocytosis (PTE) are frequent complications after kidney transplantation and are important risk factors for cardiovascular events. Losartan decreases serum uric acid and hemoglobin (Hb) concentrations and may be a useful agent for treatment of hyperuricemia and PTE.

OBJECTIVE

To evaluate the influence of losartan on serum creatinine (SCr), serum uric acid, and hemoglobin (Hb) concentrations in patients after kidney transplantation and to evaluate the safety profile of losartan in these patients.

PATIENTS AND METHODS

Sixty-six Han Chinese patients (43 men and 23 women; mean [SD] age, 40.45 [11.50] years) were enrolled in the study. All patients had undergone a first cadaveric donor kidney transplantation at least 3 months previously and had stable graft function with SCr concentration less than 176.8 micromol/L and Hb concentration greater than 110 g/L. The patients were divided into 2 groups (losartan group, n = 34; and control group, n = 32) according to the odevity of patient identification number. Patients in the losartan group received losartan, 50 mg/d; patients in the control group did not receive losartan. Each patient was followed up for 6 months.

RESULTS

Nine patients in the losartan group and 5 patients in the control group dropped out because of acute renal insufficiency, anemia, acute rejection, or poor compliance. The serum uric acid concentration in the losartan group continuously decreased at months 1, 2, 3, and 6 (P = .12, P = .01, P = .04, and P = .005 compared with baseline, and P = .02, P = .003, P = .02, and P = .006 compared with control), especially in the patients with hyperuricemia (P = .02, P < .001, P = .003, and P < .001 compared with baseline, and P = .02, P = .002, P = .02, and P = .002 compared with control). The Hb level in the losartan group decreased significantly at months 1, 2, 3, and 6 (P = .003, P < .001, P = .004, and P = 0.02 compared with baseline, and P = .001, P < .001, P = .001, and P = .005 compared with control), especially in patients with PTE. In patients without PTE, there was no significant decline in Hb concentration in the losartan group compared with baseline. There was no significant decline in estimated glomerular filtration rate in the losartan group.

CONCLUSIONS

Losartan may be an effective agent for treatment of hyperuricemia and PTE in Han Chinese patients after kidney transplantation. However, in some patients, losartan may not be safe.

Toward TeV conformality

We study the chiral properties of an SU(3) gauge theory with N{f} massless Dirac fermions in the fundamental representation when N{f} is increased from 2 to 6. For N{f}=2, our lattice simulations lead to a value of psi psi/F{3}, where F is the Nambu-Goldstone-boson decay constant and psi psi is the chiral condensate, which agrees with the measured QCD value. For N{f}=6, this ratio shows significant enhancement, presaging an even larger enhancement anticipated as N{f} increases further, toward the critical value for transition from confinement to infrared conformality.

Effect of noise-induced nucleation on grain size distribution studied via the phase-field crystal method

We contribute to the more detailed understanding of the phase-field crystal model recently developed by Elder et al (2002 Phys. Rev. Lett. 88 245701), by focusing on its noise term and examining its impact on the nucleation rate in a homogeneously solidifying system as well as on successively developing grain size distributions. In this context we show that principally the grain size decreases with increasing noise amplitude, resulting in both a smaller average grain size and a decreased maximum grain size. Despite this general tendency, which we interpret based on Panfilis and Filiponi (2000 J. Appl. Phys. 88 562), we can identify two different regimes in which nucleation and successive initial growth are governed by quite different mechanisms.

Placement of covered stents for the treatment of direct carotid cavernous fistulas

BACKGROUND AND PURPOSE

Endovascular detachable balloon occlusion and coil occlusion are 2 well-established options for the treatment of direct carotid cavernous fistulas (DCCFs). In recent years, covered stents have been applied in the treatment of neurovascular pathologies such as aneurysms, pseudoaneurysms, arterial dissections, and DCCFs. The purpose of this study was to investigate the clinical efficacy of covered stents for the treatment of DCCFs.

MATERIALS AND METHODS

Ten consecutive patients underwent covered-stent placement after failure of detachable balloon occlusion for the treatment of their DCCFs. Clinical and angiographic follow-up ranged from 5 to 48 months (mean, 18.2 months) after stent placement.

RESULTS

Stent placement was technically successful in all except 1 patient. In this patient, stent placement failed after multiple attempts because of rigidity of the Jostent GraftMaster Coronary Stent Graft and the tortuous anatomy of the internal carotid artery (ICA). Complete exclusion of the fistula was achieved in 6 patients immediately after stent deployment. Endoleak was observed in 3 patients. Re-dilation of the stent avoided the endoleak in 2 patients; in 1 of these 2 patients, formerly improved symptoms recurred the next morning and the ipsilateral ICA was occluded with detachable balloons. Spasm of the ICA was observed in most of the patients after stent placement; however, angioplasty was not required. Symptoms improved in all patients after treatment, without thromboembolic events. Follow-up cerebral angiography showed complete exclusion of all DCCFs and stent patency without intrastent stenosis in the 8 patients who had successful deployment of the stent.

CONCLUSIONS

Although a larger sample and expanded follow-up are needed, our series shows that covered stents can be used in the treatment of DCCFs with symptomatic relief.

High-speed nonlinear finite element analysis for surgical simulation using graphics processing units

The use of biomechanical modelling, especially in conjunction with finite element analysis, has become common in many areas of medical image analysis and surgical simulation. Clinical employment of such techniques is hindered by conflicting requirements for high fidelity in the modelling approach, and fast solution speeds. We report the development of techniques for high-speed nonlinear finite element analysis for surgical simulation. We use a fully nonlinear total Lagrangian explicit finite element formulation which offers significant computational advantages for soft tissue simulation. However, the key contribution of the work is the presentation of a fast graphics processing unit (GPU) solution scheme for the finite element equations. To the best of our knowledge, this represents the first GPU implementation of a nonlinear finite element solver. We show that the present explicit finite element scheme is well suited to solution via highly parallel graphics hardware, and that even a midrange GPU allows significant solution speed gains (up to 16.8 x) compared with equivalent CPU implementations. For the models tested the scheme allows real-time solution of models with up to 16,000 tetrahedral elements. The use of GPUs for such purposes offers a cost-effective high-performance alternative to expensive multi-CPU machines, and may have important applications in medical image analysis and surgical simulation.

First Report of Leaf Smut on Fescue (Festuca rubra) Caused by Urocystis agropyri in Interior Alaska

In June and early July of 2003 and July of 2007, a smut disease was found on fescue (Festuca rubra L.) at the Fairbanks Golf and Country Club and vicinities, Interior Alaska. Diseased plants were pale green-to-slightly yellow and stunted. The lesions were long, narrow, yellowish green streaks parallel to the veins of leaves and sheaths. At a later stage, sori developed under the epidermis and the leaves and sheaths turned silvery gray. Rupture of the epidermis resulted in the release of masses of black spores that covered the leaves, especially along and within infected sheaths. Microscopic observation showed spore balls consisting of one-to-four, dark reddish brown teliospores surrounded by small, hyaline-to-light brown sterile cells. The spore balls were globose to elongate and 16 to 32 × 18 to 38 μm. The teliospores were globose, dark reddish brown, and 7.5 to 20 μm in diameter. Urocystis agropyri is recognized by R. W. Smiley et al. (2) and J. D. Smith et al. (3) as occurring on turf grasses; K. Vánky (4) restricts this species to Elymus spp. and recognizes U. ulei as the valid species infecting Festuca spp, including F. rubra. On the basis of host symptoms and morphology of spores, the smut found on F. rubra in Alaska fits better with published descriptions of U. agropyri (Preuss) Schrot (2,3), however, it likely is not conspecific with flag smut of wheat. For molecular verification of this identification, DNA was isolated from teliospores with a DNeasy Plant Mini Kit (Qiagen, Valencia, CA). Primers were designed for amplification of the large subunit ribosomal gene based on the only two published sequences of U. ranunculi (Lib.) Moesz (GenBank Accession No. AF009879) and U. colchici (Schltdl.) Rabenh (GenBank Accession No. AF009878) (1). A 400-bp PCR product was amplified by the forward primer 3'-GCATTGTAAACTCAGAAGTGTTATCCG-5' and reverse primer 5'-TTCCCTAAACCTATATCCGGCG-3'. Nucleotide sequence of the PCR product (GenBank Accession No. AY547283) shared 97.7% homology with U. ranunculi and 98.2% with U. colchici. Comparison of nucleotide sequences will be more meaningful in the identification of species of Urocystis when additional sequences are published. To our knowledge, this is the first report of U. agropyri from turfgrass in Alaska. References: (1) D. Begerow et al. Can. J. Bot. 75:2045, 1997. (2) R. W. Smiley et al. Compendium of Turfgrass Diseases. 3rd ed. The American Phytopathological Society, St Paul, MN, 2005. (3) J. D. Smith et al. Page 189 in: Fungal Diseases of Amenity Turf Grassess. E. & F. N. Spon, London, 1989. (4) K. Vánky. Page 308 in: European Smut Fungi. Gustav Fischer Verlag, NY. 1994.

Oral administration of grape seed proanthocyanidin extracts downregulate RAGE dependant nuclear factor- kappa BP65 expression in the hippocampus of streptozotocin induced diabetic rats

Chronic degenerative brain disease in diabetes, known as 'diabetic encephalopathy', is a recognized complication that can occur due to long-standing diabetes in patients. It is defined by chronic cognitive disturbance and it is thought to relate to regional tissue pathological changes in the brain. Furthermore, hyperglycemia induced activation of the AGE (S)/RAGE/NF-kappaB pathway may play an important role in the pathogenesis of the degenerative changes seen in the diabetic hippocampus. To help prevent the development of and to potentially treat this brain disease, effective interventions directed toward key molecular target(s) are required. Grape seed proanthocyanidin extracts (GSPE), which are the anti-oxidants derived from grape seeds, have been reported to possess a variety of potent properties. As a consequence, they may have therapeutic effects in the prevention and treatment of complications in patients with diabetes. In this study, we firstly examined whether GSPE could attenuate the structural degenerative changes in the diabetic hippocampus in a rodent model of diabetes. Secondly, we addressed if such effects of GSPE may be occurring through modulation of the receptor for advanced glycation end products (RAGE) and/or nuclear factor-kappa BP65 (NF-kappaBP65). Hippocampi from GSPE treated STZ induced diabetic rats were immunohistochemically stained for glial fibrillary acidic protein, RAGE and NF-kappaBP65 and for morphological observations. Western blot was used to detect the proteins of RAGE and NF-kappaBP65. Real time, reverse transcriptase coupled to polymerase chain reaction was used for quantitative determination of mRNA for RAGE and NF-kappaBP65. Analysis of data showed that long term chronic hyperglycemia caused the overexpression of AGE (S)/RAGE and NF-kappaBp65 in the CA region of hippocampus in STZ induced diabetic rats. GSPE decreased the expression of RAGE and NF-kappaBP65 at a daily oral dosage of 250 mg/kg. This study provides indication that GSPE can prevent structural changes of diabetes in the rat brain and it suggests that GSPE might be a useful remedy in the treatment of diabetic encephalopathy. In addition, it implicates the potential pathological role of RAGE and NF-kappaBP65 in diabetic encephalopathy.

A dose escalating, placebo controlled, double blind, single dose and multidose, safety and tolerability study of fontolizumab, a humanised anti-interferon gamma antibody, in patients with moderate to severe Crohn's disease

INTRODUCTION

This study was designed to evaluate the safety of fontolizumab, a humanised anti-interferon gamma antibody, in patients with moderate to severe Crohn's disease (CD).

PATIENTS AND METHODS

Forty five patients with a CD activity index (CDAI) of 250-450 were randomised in a double blind, placebo controlled, dose escalating fashion to receive single doses of fontolizumab (0.1, 1.0, and 4.0 mg/kg) or placebo. By day 29, patients with clinical response were re-randomised to receive three additional doses of one half their initial fontolizumab dose or placebo at four weekly intervals. Primary objectives were safety and tolerability. Secondary outcomes included assessments of immunogenicity, clinical activity, and potential pharmacodynamic surrogates.

RESULTS

Treatment was generally well tolerated. There were slightly more reports of chills, flu-like syndrome, asthenia, nausea, and vomiting in the 1.0 mg and 4.0 mg/kg fontolizumab cohorts. Two serious adverse events rated as worsening of CD occurred under fontolizumab. Antibodies to fontolizumab were confirmed in one patient. No differences in clinical activity parameters were noted between any of the active treatment groups and placebo, with the placebo group having a particularly favourable outcome (60% response and 40% remission). By day 29, a more enhanced decrease in median Crohn's disease endoscopic index of severity (p = 0.02) and serum C reactive protein (p<0.001) was observed in the 4.0 mg/kg (n = 14) fontolizumab cohort compared with placebo (n = 10). Pharmacodynamic effects were observed by immunohistochemistry.

CONCLUSIONS

Fontolizumab was well tolerated with minimal immunogenicity at doses of up to 4.0 mg/kg in patients with CD. A biological activity of fontolizumab is suggested.

Agrobacterium-mediated large-scale transformation of wheat (Triticum aestivum L.) using glyphosate selection

An Agrobacterium-mediated transformation system with glyphosate selection has been developed for the large-scale production of transgenic plants. The system uses 4-day precultured immature embryos as explants. A total of 30 vectors containing the 5-enol-pyruvylshikimate-3-phosphate synthase gene from Agrobacterium strain CP4 (aroA:CP4), which confers resistance to glyphosate, were introduced into wheat using this system. The aroA:CP4 gene served two roles in this study-selectable marker and gene of interest. More than 3,000 transgenic events were produced with an average transformation efficiency of 4.4%. The entire process from isolation of immature embryos to production of transgenic plantlets was 50-80 days. Transgenic events were evaluated over several generations based on genetic, agronomic and molecular criteria. Forty-six percent of the transgenic events fit a 3:1 segregation ratio. Molecular analysis confirmed that four of six lead transgenic events selected from Agrobacterium transformation contained a single insert and a single copy of the transgene. Stable expression of theAROA:CP4 gene was confirmed by ELISA through nine generations. A comparison of Agrobacterium-mediated transformation to a particle bombardment system demonstrated that the Agrobacterium system is reproducible, has a higher transformation efficiency with glyphosate selection and produces higher quality transgenic events in wheat. One of the lead events from this study, no. 33391, has been identified as a Roundup Ready wheat commercial candidate.

Chrisman-Snook ankle ligament reconstruction outcomes--a local experience

INTRODUCTION

Chrisman-Snook reconstruction is a surgical method of treating chronic lateral ankle instability. This study aims to examine the outcome and possible factors including joint hypermobility that may influence the outcome in our local population.

MATERIALS AND METHODS

Twenty-four ankles with chronic lateral ankle instabilities were treated with the Chrisman-Snook reconstruction procedure between May 1995 and November 1997. Fifteen were available for review at an average follow-up period of 35.3 months, ranging from 26 to 51 months. The patients were young and the average age was 24 years. The lateral ligaments were reconstructed by rerouting half the peroneus brevis tendon, based distally, through the lateral malleolus and anchoring it to the calcaneum. Functional results were assessed using the Kaikkonen ankle stability score. Joint hypermobility was assessed by the Beighton et al score.

RESULTS

Excellent results were achieved in ten cases, good in four, and fair in one. None had poor results. Best outcomes tended to occur in patients with joint hypermobility. Complications included decreased sensation in a small area of the lateral foot.

CONCLUSIONS

Chrisman-Snook reconstruction is a surgical option for young patients who have failed conservative treatment for chronic ankle instability. In our local population with a higher incidence of joint hypermobility, it gave good results with few serious complications.

The renal expression of heat shock protein 47 and collagens in acute and chronic experimental diabetes in rats

Glomerulosclerosis and tubulointerstitial fibrosis are the main structural changes found in the later stages of diabetic nephropathy, which is clinically characterized by proteinuria, and progressive renal insufficiency. Heat shock protein (HSP) 47, a collagen-binding stress protein, has a specific role in the intracellular processing of procollagen molecules during collagen synthesis. It is implicated in the pathogenesis of various fibrotic diseases. However, the expression and significance of HSP47 in acute and chronic phases of diabetic nephropathy is not yet known. In this study, we studied the expression of HSP47 in the kidneys obtained from streptozotocin-induced diabetic rats, in both short- and long-term diabetes. To determine the renal expression of HSP47, and collagens (type III and IV) in acute (days 1, 3 and 14) and chronic (weeks 4, 12 and 24) diabetes, we have performed a time-course study using streptozotocin-induced diabetic rats. The expression pattern of alpha-smooth muscle actin (to identify mesangial cell damage), vimentin (to identify tubular epithelial cell damage), and desmin (to identify glomerular epithelial cell damage) was also determined in kidneys of these diabetic rats. Antibodies specific for HSP47, type III and type IV collagens, alpha-smooth muscle actin, vimentin, and desmin were used to assess the relative expression of their proteins in paraffin-embedded kidney sections by immunohistochemistry. Compared to control rat kidneys, no significant changes in the expression of HSP47 was found in the kidneys of acute diabetic rats. However a significant increase in the expression of HSP47 was noted in the kidneys of chronic diabetic rats; increased expression of HSP47 correlated with an increased renal deposition of types III and IV collagens. Similarly, compared to kidneys of control and acute diabetic rats, an increased expression of alpha-smooth muscle actin (in mesangial cells), vimentin (in tubular epithelial cells), and desmin (in glomerular epithelial cells) was detected in the kidneys of chronic diabetic rats; by dual immunostaining, these phenotypically-altered renal cells in kidneys of chronic diabetic rats were found to be HSP47-producing cells. Importantly, HSP47 up-regulation coincided with the initiation and progression of renal fibrosis, as determined by the expression and deposition of collagens. Our results strongly support a pathological role for HSP47 in the later stages (sclerotic phase) of streptozotocin-induced diabetic nephropathy, which is associated with glomerulosclerosis and tubulointerstitial fibrosis.

Proteasome-independent disruption of PML oncogenic domains (PODs), but not covalent modification by SUMO-1, is required for human cytomegalovirus immediate-early protein IE1 to inhibit PML-mediated transcriptional repression

Human cytomegalovirus (HCMV) major immediate-early protein IE1 is an abundant 72-kDa nuclear phosphoprotein that is thought to play an important role in efficient triggering of the lytic cycle, especially at low multiplicity of infection. The best-known properties of IE1 at present are its transient targeting to punctate promyelocytic leukemia protein (PML)-associated nuclear bodies (PML oncogenic domains [PODs] or nuclear domain 10 [ND10]), with associated displacement of the cellular PML tumor suppressor protein into a diffuse nucleoplasmic form and its association with metaphase chromosomes. Recent studies have shown that the targeting of PML (and associated proteins such as hDaxx) to PODs is dependent on modification of PML by ubiquitin-like protein SUMO-1. In this study, we provide direct evidence that IE1 is also covalently modified by SUMO-1 in both infected and cotransfected cells, as well as in in vitro assays, with up to 30% of the protein representing the covalently conjugated 90-kDa form in stable U373/IE1 cell lines. Lysine 450 was mapped as the major SUMO-1 conjugation site, but a point mutation of this lysine residue in IE1 did not interfere with its targeting to and disruption of the PODs. Surprisingly, unlike PML or IE2, IE1 did not interact with either Ubc9 or SUMO-1 in yeast two-hybrid assays, suggesting that some additional unknown intranuclear cofactors must play a role in IE1 sumoylation. Interestingly, stable expression of either exogenous PML or exogenous Flag-SUMO-1 in U373 cell lines greatly enhanced both the levels and rate of in vivo IE1 sumoylation during HCMV infection. Unlike the disruption of PODs by the herpes simplex virus type 1 IE110(ICP0) protein, the disruption of PODs by HCMV IE1 proved not to involve proteasome-dependent degradation of PML. We also demonstrate here that the 560-amino-acid PML1 isoform functions as a transcriptional repressor when fused to the GAL4 DNA-binding domain and that wild-type IE1 inhibits the repressor function of PML1 in transient cotransfection assays. Furthermore, both IE1(1-346) and IE1(L174P) mutants, which are defective in displacing PML from PODs, failed to inhibit the repression activity of PML1, whereas the sumoylation-negative IE1(K450R) mutant derepressed as efficiently as wild-type IE1. Taken together, our results suggest that proteasome-independent disruption of PODs, but not IE1 sumoylation, is required for efficient IE1 inhibition of PML-mediated transcriptional repression.

Single-site beta-diiminate zinc catalysts for the alternating copolymerization of CO2 and epoxides: catalyst synthesis and unprecedented polymerization activity

Synthetic routes to zinc beta-diiminate complexes are reported. The synthesis of 11 beta-diimine [(BDI)-H] ligands, with varying N-aryl substituents and bridging structures, is described. These ligands are converted to (BDI)ZnX complexes (X = OAc, Et, N(SiMe3)2, Br, Cl, OH, OMe, O(i)Pr). X-ray structural data revealed that all zinc complexes examined exist as micro-X-bridged dimers in the solid state, with the exception of the zinc ethyl and amido complexes which were monomeric. Complexes of the form (BDI)ZnOR (R = alkyl, acyl) and (BDI)ZnN(SiMe3)2 are highly active catalysts for the alternating copolymerization of epoxides and CO2. Copolymerizations of cyclohexene oxide (CHO) and CO2 with (BDI-1)ZnX [(BDI-1) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)imino)-2-pentene)] and (BDI-2)ZnX [(BDI-2) = 2-((2,6-diethylphenyl)amido)-4-((2,6-diethylphenyl)imino)-2-pentene)], where X = OAc, Et, N(SiMe3)2, Br, Cl, OH, OMe, O(i)Pr, were attempted at 50 degrees C and 100 psi CO2. Complexes with X = OAc, N(SiMe3)2, OMe, O(i)Pr all produced polycarbonate by the alternated insertion of CHO and CO2 with similar catalytic activities, comparable molecular weights, and narrow molecular weight distributions (MWD approximately 1.1), indicating the copolymerizations are living. Furthermore, ligand effects were shown to dramatically influence the polymerization activity as minor steric changes accelerated or terminated the polymerization activity.

[The outlook of using chitosan related materials in nerve regeneration]

Chitosan is a kind of biodegradable materials with excellent biocompatibility. This article interpreted the progress and outlook of using chitosan related materials in nerve regeneration from the following points: the positive charges on chitosan, its ability to adsorb proteins, the specific adhesion of nerve cells on chitosan, and the surface roughness, aperture and surface topography of chitosan.

NXY-059, a novel free radical trapping compound, reduces cortical infarction after permanent focal cerebral ischemia in the rat

Free radicals have gained wide acceptance as mediators of cerebral ischemic injury. It has previously been reported that a spin trap nitrone, alpha-phenyl-N-tert-butyl nitrone (PBN), can reduce infarct volumes in rats subjected to either permanent or transient focal cerebral ischemia. A recent study has demonstrated that NXY-059, a novel free radical trapping nitrone compound, has a neuroprotective effect against transient focal cerebral ischemia. This study was designed to determine the effect of NXY-059 in a rodent model of permanent focal cerebral ischemia. Male spontaneously hypertensive rats were subjected to permanent middle cerebral artery occlusion (MCAO) by placement of a microaneurysm clip on the middle cerebral artery (MCA). Animals were divided into three groups: (1) physiological saline given as a 1 ml/kg i.v. bolus administered 5 min post MCAO followed immediately by a continuous i.v. infusion of 0.5 ml/h of physiological saline for 24 h (n=10); (2) 30 mg/kg, 1 ml/kg, i.v. bolus of NXY-059 dissolved in physiological saline administered 5 min post MCAO followed immediately by a continuous i.v. infusion of 30 mg/kg/h, 0.5 ml/h, of NXY-059 for 24 h (n=9); (3) 60 mg/kg, 1 ml/kg, i.v. bolus of NXY-059 dissolved in physiological saline administered 5 min post MCAO followed immediately by a continuous i.v. infusion of 60 mg/kg/h, 0.5 ml/h, of NXY-059 for 24 h (n=12). Infarction was quantified after a survival period of 24 h. Differences in infarct volume were examined with one-way ANOVA following Dunnet's multiple comparison test. The percentage of cortical infarction in the saline control group was 22.6 +/- 6.8% (mean+/-S.D.) of contra-lateral hemisphere, and in the 30 mg/kg/h NXY-059-treated group was 17.4% +/- 6.8% (NS). Plasma concentration (microM/l) of NXY-059 in the 30 mg/kg/h group was 80.2 +/- 52.2 (n=9), while in the 60 mg/kg/h group plasma concentration (microM/l) of NXY-059 was 391.0 +/- 207.0 (n=10). Infarction in the 60 mg/kg/h NXY-059-treated group was significantly reduced (P=0.009) to 14.5 +/- 5%. Our preliminary data demonstrate that administration of NXY-059 (60 mg/kg/h for 24 h) ameliorates cortical infarction in rats subjected to permanent focal cerebral ischemia with 24 h survival.

[Inhibitory effect of gelsemium alkaloids extract on hepatic carcinoma HepG2 cells in vitro]

The inhibitory effect of gelsemium alkaloids exstract (GAA) on HepG2 cells in vitro were studied by crystal violet dyeing method. The morphological change of HepG2 cells were observed with optical microscope. The alterations of cell cycle induced by GAA were analyzed with flow cytometry. The results showed that HepG2 cells exposed to GAA 10 micrograms/ml was inhibited significantly (P < 0.05). The inhibitory effect appeared in a dose- and time-dependent manner. HepG2 cells showed nuclear chromosome segmentation and condensation after GAA treatment. There emerged obvious Sub-G1 peak in the DNA histogram of HepG2 cells. GAA has a significant inhibition on HepG2 cells in vitro. The mechanism of antitumor action may be related to their apoptosis inducing activity.

Expression of the melanin-concentrating hormone (MCH) receptor mRNA in the rat brain

The melanin-concentrating hormone (MCH) system is thought to be an important regulator of food intake. Recently the orphan G protein-coupled receptor SLC-1 was identified as the MCH receptor (MCHR). Preliminary analyses of MCHR mRNA distribution have supported a role for the MCH system in nutritional homeostasis. We report here a complete anatomical distribution of the MCHR mRNA. We have found high levels of expression of MCHR mRNA in most anatomical areas implicated in control of olfaction, with the exception of the main olfactory bulb. Dense labeling was also detected in the hippocampal formation, subiculum, and basolateral amygdala, all of which are important in learning and memory, and in the shell of the nucleus accumbens, a substrate for motivated behavior and feeding. Within the hypothalamus, MCHR mRNA was moderately expressed in the ventromedial nucleus, arcuate nucleus, and zona incerta, all of which serve key roles in the neuronal circuitry of feeding. In the brainstem, strong expression was observed in the locus coeruleus, which is implicated in arousal, as well as in nuclei that contribute to orofacial function and mastication, including the facial, hypoglossal, motor trigeminal, and dorsal motor vagus nuclei. In most regions there was a good correspondence between MCHR mRNA distribution and that of MCH-immunoreactive fibers. Taken together, these data suggest that MCH may act at various levels of the brain to integrate various aspects of feeding behavior. However, the extensive MCHR distribution throughout the brain suggests that this receptor may play a role in other functions, most notably reinforcement, arousal, sensorimotor integration, and autonomic control.

Age-related changes in the mouse outer retina

PURPOSE

To define the physiological and structural changes that may accompany aging in the normal mouse retina.

METHODS

C57BL/6 mice were maintained under cyclic light for either 2, 6, or 12 months. After rod- and cone-mediated corneal electroretinograms (ERG's) were recorded from anesthetized animals, the retinal structure was quantitatively examined. Photoreceptor cell density was measured within 100-microm regions of the central superior and inferior retina. Cone photoreceptor subtypes were identified by immunocytochemistry.

RESULTS

The amplitudes of rod- and cone-mediated ERG's were reduced in older mice, although the overall ERG wave-form did not change appreciably and implicit times were not changed in an age-dependent fashion. In comparison, there was no significant age-related decline in rod or cone photoreceptor density.

CONCLUSIONS

The amplitude of the mouse ERG declines with age. This change does not appear to reflect a change in the structural integrity of the photoreceptor cells. In functional studies of murine models of late-onset retinal disorders, it will be important to take these changes into consideration.

Polymerization of lactide with zinc and magnesium beta-diiminate complexes: stereocontrol and mechanism

A series of zinc(II) and magnesium(II) alkoxides based upon a beta-diiminate ligand framework has been prepared. [(BDI-1)ZnO(i)Pr](2) [(BDI-1) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)imino)-2-pentene] exhibited the highest activity and stereoselectivity of the zinc complexes studied for the polymerization of rac- and meso-lactide to poly(lactic acid) (PLA). [(BDI-1)ZnO(i)()Pr](2) polymerized (S,S)-lactide to isotactic PLA without epimerization of the monomer, rac-lactide to heterotactic PLA (P(r) = 0.94 at 0 degrees C), and meso-lactide to syndiotactic PLA (P(r) = 0.76 at 0 degrees C). The polymerizations are living, as evidenced by the narrow polydispersities of the isolated polymers in addition to the linear nature of number average molecular weight versus conversion plots and monomer-to-catalyst ratios. The substituents on the beta-diiminate ligand exert a significant influence upon the course of the polymerizations, affecting both the degree of stereoselectivity and the rate of polymerization. Kinetic studies with [(BDI-1)ZnO(i)Pr](2) indicate that the polymerizations are first order with respect to monomer (rac-lactide) and 1.56 order in catalyst. Polymerization experiments with [(BDI-1)MgO(i)Pr](2) revealed that this complex is extremely fast for the polymerization of rac-lactide, polymerizing 500 equiv in 96% yield in less than 5 min at 20 degrees C.

Elevated expression of proprotein convertases alters breast cancer cell growth in response to estrogen and tamoxifen

Two proprotein convertase cDNAs, PC1 and furin, were stably transfected into the human breast cancer cell line MCF-7. The PC1 or furin over-expressing cells possessed an altered morphology. When grown in vitro in a serum-free medium, the population doubling time of the convertase-transfected cells was twice that of wild-type (WT) cells. High concentrations of estradiol stimulated the growth of all three cell types to a similar extent; however, at low concentrations of estradiol, the convertase-transfected cells grew more slowly than WT cells. In athymic nude mice implanted with 5 mg estradiol pellets, the growth of tumors of convertase-transfected MCF-7 cells was stimulated to a degree similar to that of WT MCF-7 tumors. However, in mice implanted with lower-dose (1.5 mg) estradiol pellets, the tumors of PC1- or furin-transfected MCF-7 cells grew approximately five times slower than those of WT MCF-7 cells. In mice implanted with tamoxifen pellets, tumors of PC1- or furin-transfected MCF-7 cells regressed approximately five times slower than the WT tumors. This study shows that the over-expression of proprotein convertases confers a greater estrogen dependency and anti-estrogen resistance on human breast cancer cells.

CD45 is a JAK phosphatase and negatively regulates cytokine receptor signalling

The regulation of tyrosine phosphorylation and associated signalling through antigen, growth-factor and cytokine receptors is mediated by the reciprocal activities of protein tyrosine kinases and protein tyrosine phosphatases (PTPases). The transmembrane PTPase CD45 is a key regulator of antigen receptor signalling in T and B cells. Src-family kinases have been identified as primary molecular targets for CD45 (ref. 4). However, CD45 is highly expressed in all haematopoietic lineages at all stages of development, indicating that CD45 could regulate other cell types and might act on additional substrates. Here we show that CD45 suppresses JAK (Janus kinase) kinases and negatively regulates cytokine receptor signalling. Targeted disruption of the cd45 gene leads to enhanced cytokine and interferon-receptor-mediated activation of JAKs and STAT (signal transducer and activators of transcription) proteins. In vitro, CD45 directly dephosphorylates and binds to JAKs. Functionally, CD45 negatively regulates interleukin-3-mediated cellular proliferation, erythropoietin-dependent haematopoieisis and antiviral responses in vitro and in vivo. Our data identify an unexpected and novel function for CD45 as a haematopoietic JAK phosphatase that negatively regulates cytokine receptor signalling.

Short-term effects of formaldehyde on peak expiratory flow and irritant symptoms

The authors studied the respiratory effects of formaldehyde exposure among students who dissected cadavers in a gross anatomy laboratory. Peak expiratory flow and respiratory symptoms were measured before and after each weekly laboratory session. Each of 38 students was exposed to formaldehyde for 2.5 hr/wk for 14 wk. Individual, daily formaldehyde measurements averaged 1.1 ppm (standard deviation = 0.56 ppm). Multivariate models demonstrated two different time scales of effect of formaldehyde on peak expiratory flow: (1) exposure during the previous 2.5 hr reduced peak expiratory flow by -1.0% per ppm, and (2) average exposure during all preceding weeks reduced peak expiratory flow by an additional -0.5% per ppm of formaldehyde. However, the short-term exposure effect was diminished during the first 4 wk, suggesting at least partial acclimatization. Symptom reporting was also associated with exposure during the previous 2.5 hr, and similar evidence of acclimatization was observed. These results suggest that there are two different time scales of response to formaldehyde, and they emphasize the need for longitudinal studies, characterized by quantitative exposure characterization, and frequent measurements of outcome.

Surgical management of infantile hypertrophic pyloric stenosis--can it be performed by general surgeons?

INTRODUCTION

Debate exists as to whether IHPS can be treated in district general hospitals as effectively as in specialist paediatric surgical units.

AIM

To review the surgical treatment of IHPS in babies admitted to a district general hospital under the care of two consultant general surgeons with a paediatric surgical interest.

PATIENTS AND METHODS

The case notes of 66 babies operated on for IHPS over a 42 month period between April 1995 and September 1998 were retrospectively reviewed. Demographics, operative details, hospital stay, and overall complications were all documented.

RESULTS

Peri-operative complications occurred in 2 patients, both requiring omental patches for duodenal perforation. Nine patients had 1 or 2 episodes of postoperative vomiting; 4 had either a wound or urinary tract infection; and 1 baby developed an incisional hernia. There was no mortality.

DISCUSSION

The complication rate seen in this series is comparable to that of specialist centres, and supports current guidelines suggesting that IHPS can be managed by general surgeons with a paediatric surgical interest in a district general hospital.

Chalcone, acyl hydrazide, and related amides kill cultured Trypanosoma brucei brucei

BACKGROUND

Protozoan parasites of the genus Trypanosoma cause disease in a wide range of mammalian hosts. Trypanosoma brucei brucei, transmitted by tsetse fly to cattle, causes a disease (Nagana) of great economic importance in parts of Africa. T. b. brucei also serves as a model for related Trypanosoma species, which cause human sleeping sickness.

MATERIALS AND METHODS

Chalcone and acyl hydrazide derivatives are known to retard the growth of Plasmodium falciparum in vitro and inhibit the malarial cysteine proteinase, falcipain. We tested the effects of these compounds on the growth of bloodstream forms of T. b. brucei in cell culture and in a murine trypanosomiasis model, and investigated their ability to inhibit trypanopain-Tb, the major cysteine proteinase of T. b. brucei.

RESULTS

Several related chalcones, acyl hydrazides, and amides killed cultured bloodstream forms of T. b. brucei, with the most effective compound reducing parasite numbers by 50% relative to control populations at a concentration of 240 nM. The most effective inhibitors protected mice from an otherwise lethal T. b. brucei infection in an in vivo model of acute parasite infection. Many of the compounds also inhibited trypanopain-Tb, with the most effective inhibitor having a Ki value of 27 nM. Ki values for trypanopain-Tb inhibition were up to 50- to 100-fold lower than for inhibition of mammalian cathepsin L, suggesting the possibility of selective inhibition of the parasite enzyme.

CONCLUSIONS

Chalcones, acyl hydrazides, and amides show promise as antitrypanosomal chemotherapeutic agents, with trypanopain-Tb possibly being one of their in vivo targets.

Endothelium-dependent relaxation of rat aorta and main pulmonary artery by the phytoestrogens genistein and daidzein

OBJECTIVE

The dietary phytoestrogens genistein and daidzein have been shown to relax agonist-preconstricted arteries in vitro; the mechanisms of relaxation remain incompletely understood. This study aimed to determine whether the relaxation of phenylephrine (PE)-constricted rat aorta and main pulmonary artery by genistein and daidzein was endothelium-dependent.

METHODS

Effects of endothelial-denudation, and pretreatment with with 100 microM L-N(G)-nitroarginine methyl ester (L-NAME) and/or 10 microM indomethacin on relaxation of PE (1 microM)-preconstricted contractures by genistein (1-100 microM) and daidzein (3-100 microM) were assessed by measuring isometric force development by rat arterial rings. The effect of L-NAME on relaxation to 17beta-estradiol (10 microM) was also measured in aorta.

RESULTS AND CONCLUSIONS

Genistein and daidzein caused concentration-dependent relaxation of aorta rings preconstricted with PE (1 microM). The IC50 values were 5.7 microM (n=8, 95% confidence limits 4.3-7.7 microM) and 36.7 microM (n=12, 95% confidence limits 25.7-44.1 microM), respectively. Removal of the endothelium and pretreatment with L-NAME (100 microM) significantly inhibited relaxation at 3, 10 and 30 microM genistein and 10 and 30 microM daidzein. The contracture evoked in rat aorta by depolarization with 75 mM K+ solution was similarly relaxed by genistein in a partially endothelium-dependent manner. 17Beta-estradiol (10 microM) caused a 48.7+/-5.0% (n=11) relaxation of the PE contracture, which was significantly reduced to 25.1+/-5.3% (n=7) by L-NAME. Relaxations brought about by 17beta-estradiol, genistein, and daidzein were not significantly affected by the genomic estrogen receptor antagonist ICI 182,780 (10 microM). Similar endothelium-dependent effects of genistein were observed in the main pulmonary artery. The results show that the relaxation of these rat arteries by concentrations of genistein and daidzein which overlap those present in human plasma after ingestion of soybean-containing meals is largely endothelium dependent.

Correlative factors of insulin resistance in essential hypertension

Essential Hypertension (EH) is correlated with a metabolic disturbance characterized by insulin resistance (IR). In this study, there were observed in 47 subjects with EH and 30 subjects with normal blood pressure. Serum levels of insulin-like growth factor-1 (IGF-1), serum levels of growth hormone (GH), the activity of erythrocyte insulin receptors (EIR), and ATP levels in erythrocytes, the insulin sensitivity index (ISI) was used to study the correlative factors of essential hypertension. 1. Among patients with EH, ISI, GH, and low-affinity insulin binding sites of EIRs (RT2) were found to be in significantly lower amounts, IGF-1 levels and the KD2 of the erythrocyte insulin receptors were noted to be significantly higher. Compared with the control group, there was a marked difference between EH group and the control group. However, no statistical difference was observed between the hypertensive group and the group with normal blood pressure as regards erythrocyte ATP levels, high-affinity insulin binding sites of EIRs (RT1), and the KD1 of EIRs. 2. In the hypertensive group, the ISI was negatively correlated with mean arterial blood pressure (MBP), a family history of hypertension, the body mass index (BMI), the waist-hip ratio (WHR) and IGF-1 levels (r=-0.614delta, -0.354**, -0.386**, -0.472**, -0.298*, delta p < 0.001, **p < 0.01, *p < 0.05), were positively correlated with RT2 and GH levels (r=0.301**, 0.275*, **p < 0.01, *p < 0.05). There were no statistically significant differences between ISI and age, sex, smoking history, drinking, RT1, KD1, and ATP levels in erythrocytes. 3. The ISI was used as the dependent variable in multiple linear stepwise regression analysis. MBP (X1), a family history of EH (X2), WHR (X3), GH (X4), IGF-1 (X5), RT2 (X6), and the body mass index (X7) was used as independent variables. X1, X2, X3, X5, X6, and X7 were used in the equations. The results indicate that patients with EH also tend to have IR. We suggest that MBP, a family history of hypertension, BMI, WHR, IGF-1, and RT2 might be independent factors affecting IR in cases of essential hypertension.

[Changes of collagenase activity in immune hepatic fibrosis following pig's serum injection and therapeutic effect of HanDanGanLe]

OBJECTIVE

To investigate the changes of collagenase activity in immune hepatic fibrosis following pig's serum injection and the therapeutic effect of HanDanGanLe.

METHODS

Pig's serum was injected intraperitoneally to Wistar rats to duplicate the hepatic fibrosis model due to immunologic injury. HanDanGanLe was used as therapeutic medicine and colchicine as control. The animals were killed at 12th week to detect hepatic collagenase activity, the staining semiquantity of hepatic collagenous fibre, and the content of hepatic collagen.

RESULTS

HanDanGanLe can increase collagenase activity, decrease the content of collagenous fibre and collagen in the liver. The beneficial effect achieved in HanDanGanLe-treatment group especially in high-dose group in comparison to colchicine-treatment group.

CONCLUSION

HanDanGanLe can effectively increase collagenase activity, improve collagen degradation, and abate hepatic fibrosis.

[Detection of mutant p53 gene at resection margin of the bronchus and cancer tissues to predict lung cancer recurrence.]

BACKGROUND

To investigate the mutations of p53 gene at the resection margins of the bronchus and cancer tissues , and to predict lung cancer recurrence.

METHODS

PCR-SSCP technique was used to detect mutation of p53 gene at the resection margin of the bronchus (no cancer cells remained by gross pathological examination) , cancer tissue and normal tissue of the lungs in 50 patients with lung cancers and 7 patients with non-cancerous pulmonary diseases. Local recurrence at the resection margin of bronchus and distant metastasis were investigated.

RESULTS

Of the 50 patients , 14 cases (28 %) had p53 gene mutation at the resection margin of bronchus , and 28 cases (56 %) had p53 gene mutations in their cancer tissue. The mutations were not found in normal tissues of the 50 patients and in tissues of the 7 control patients. The mutation rate of p53 gene in cancer tissue was 100 %(2/ 2) for small cell lung cancer , 65 %(13/ 20) for squamous-cell carcinoma , 60 %(6/ 10) for adenosquamous cell carcinoma , 38. 9 %(7/ 18) for adenocarcinoma. Mutation rate of p53 gene was 72. 7 %(16/ 22) in stage III lung cancer , 58. 3 %(7/ 12) in stage II, 25 %(4/ 16) in stage I. During follow-up (ranged from 3 months to 16 months) , 6 of 14 patients (42. 9 %) with mutant p53 gene at the resection margin had local recurrence. There was no recurrence in patients without mutant p53 gene at the resection margin. Seventeen of 28 patients (60. 7 %) with mutant p53 gene in cancer tissue had recurrence or metastasis , but only 5 of 22 patients (22. 7 %) without mutant p53 gene had local recurrence ( P < 0. 05) .

CONCLUSIONS

By testing mutations of p53 gene at the resection margins of bronchus , we may predict local recurrence of lung cancer. Patients with mutant p53 gene in cancer tissue appear to have a substantially increased risk of recurrence and metastasis of lung cancer.