Induction of Human Factor VIII Inhibitors in Rats by Immunization with Human Recombinant Factor VIII: a Small Animal Model for Humans with High Responder Inhibitor Phenotype

Hemophilia A is a clotting disorder that is due to reduced or absent coagulation factor VIII (FVIII) activity. In approximately 25% of people with severe hemophilia A, standard treatment with intravenous plasma-derived or recombinant FVIII (rFVIII) induces anti-FVIII antibodies that inhibit FVIII activity (inhibitors). We describe the development of a rat model to study the formation of inhibitors. Immunization of rats with human rFVIII in adjuvant induced an anti-human rFVIII antibody response characteristic of an anti-FVIII inhibitor response in hemophilia A patients. The rats exhibited a rapid, polyclonal secondary antibody response to human rFVIII. These antibodies were reactive against epitopes located in the heavy and light chains. All the rFVIII-immunized rats developed antibodies against the FVIII C2 domain, a region of major reactivity in hemophilia A patients with inhibitors. Furthermore, competition ELISAs demonstrated that rat and human anti-FVIII antibodies recognized identical or overlapping epitopes of the FVIII molecule. The rat anti-FVIII antibodies also functioned as human FVIII inhibitors with titers ranging from 120 to 2048 Bethesda Units (B.U.). We propose that this rat model may be useful to investigate immune responses to FVIII and may lead to better therapies for FVIII inhibitors.

Induction of Human Factor VIII Inhibitors in Rats 2: Fine Mapping of Rat anti-Human rFVIII Antibodies

Inhibiting antibodies in patients with hemophilia A pose a significant therapeutic dilemma in the treatment of bleeding episodes. The genetic factors which predispose hemophiliacs to inhibitors and the optimal method for inhibitor suppression remain obscure. Hence, an animal model of the human FVIII inhibitor response is of potential value. Sprague-Dawley rats immunized with human recombinant FVIII (rFVIII) subsequently developed abnormal coagulation parameters coincident with the development of an immune response to the human protein. The epitopes for the resultant rat anti-rFVIII antibodies were mapped using a random fragment expression library constructed from the FVIII cDNA. Antigenic regions located within the Al, First and Second Acidic and B domains were mapped. Rat immunoglobulins reactive with the individual epitopes were immunoaffinity purified and assayed for inhibitory activity. Several of the epitopes mapped using the rat antibodies were similar to regions previously shown to be antigenic for human inhibitors. By contrast, no epitopes were mapped to the A2 domain with the techniques used. This may be due to the possible presence of conformational epitopes in this area which cannot undergo fragmentation and still retain antigenicity or the presence of relatively low concentrations of antibodies to this region. The rat model shares some similarity with both the auto- and alloimmune human response to FVIII and therefore may be a valuable model for studies on the induction and suppression of the inhibitor response.

Loss to follow-up after arthroplasty: a new use for registry data

We assessed the outcome of patients who were lost to follow-up after arthroplasty by a single surgeon. The aim was to validate the surgeon's data set with the Australian Orthopaedic Association National Joint Replacement Registry and determine the outcome of those patients lost to follow-up. Prospective data on patient demographics, operative details and outcomes of the surgeon's 1192 primary unicompartmental knee arthroplasty (UKA) procedures were analysed. There were 69 knees in patients who were lost to follow-up, among whom the Registry identified 31 deaths and eight revisions. The cumulative percentage revision (CPR) at seven years using the additional Registry data was 8.8% (95% confidence interval (CI) 7 to 11). Using the surgeon's data, the CPR at seven years was 8% (95% CI 6.3 to 10.1) for the best-case scenario where loss to follow-up was excluded, and 16% (95% CI 13.8 to 19.4) for the worst-case scenario, where all patients lost to follow-up were deemed to have been revised. There was a significantly higher mortality rate in those patients lost to follow-up. This study demonstrates that a national joint registry can be used by individual surgeons to establish more accurate revision rates in their arthroplasty patients. This is expected to facilitate a more rigorous audit of surgical outcomes by surgeons and lead to more accurate and uniform reporting of the results of arthroplasty in general.

Atomistic Simulation of the Nanoindentation of Diamond and Graphite Surfaces

Molecular dynamics simulations which make use of a many-body analytic potential function have been used to study the nanometer-scale indentation of diamond and graphite. We find that the simulation correctly reproduces experimentally determined trends in load versus penetration data. As a result, trends in mechanical properties, e.g. Young's modulus, are also reproduced.

Spinal upregulation of glutamate transporter GLT-1 by ceftriaxone: therapeutic efficacy in a range of experimental nervous system disorders

Glutamate neurotransmission is highly regulated, largely by glutamate transporters. In the spinal cord, the glutamate transporter GLT-1 is primarily responsible for glutamate clearance. Downregulation of GLT-1 can occur in activated astrocytes, and is associated with increased extracellular glutamate and neuroexcitation. Among other conditions, astrocyte activation occurs following repeated opioids and in models of chronic pain. If GLT-1 downregulation occurs in these states, GLT-1 could be a pharmacological target for improving opioid efficacy and controlling chronic pain. The present studies explored whether daily intrathecal treatment of rats with ceftriaxone, a beta-lactam antibiotic that upregulates GLT-1 expression, could prevent development of hyperalgesia and allodynia following repeated morphine, reverse pain arising from central or peripheral neuropathy, and reduce glial activation in these models. Ceftriaxone pre-treatment attenuated the development of hyperalgesia and allodynia in response to repeated morphine, and prevented associated astrocyte activation. In a model of multiple sclerosis (experimental autoimmune encephalomyelitis; EAE), ceftriaxone reversed tactile allodynia and halted the progression of motor weakness and paralysis. Similarly, ceftriaxone reversed tactile allodynia induced by chronic constriction nerve injury (CCI). EAE and CCI each significantly reduced the expression of membrane-bound, dimerized GLT-1 protein in lumbar spinal cord, an effect normalized by ceftriaxone. Lastly, ceftriaxone normalized CCI- and EAE-induced astrocyte activation in lumbar spinal cord. Together, these data indicate that increasing spinal GLT-1 expression attenuates opioid-induced paradoxical pain, alleviates neuropathic pain, and suppresses associated glial activation. GLT-1 therefore may be a therapeutic target that could improve available treatment options for patients with chronic pain.

Long-distance soliton transmission through ultralong fiber lasers

We present the first experimental demonstration (to our knowledge) of long-distance unperturbed fundamental optical soliton transmission in conventional single-mode optical fiber. The virtual transparency in the fiber required for soliton transmission, over 15 complete periods, was achieved by using an ultralong Raman fiber laser amplification scheme. Optical soliton pulse duration, pulse bandwidth, and peak intensity are shown to remain constant along the transmission length. Frequency-resolved optical gating spectrograms and numerical simulations confirm the observed optical soliton dynamics.

Safety and pharmacokinetics of a recombinant factor VIII with pegylated liposomes in severe hemophilia A

BACKGROUND

BAY 79-4980 is a sucrose-formulated recombinant factor VIII (rFVIII-FS) combined with pegylated liposomes to prolong activity.

OBJECTIVES

To investigate the safety, tolerability, bioavailability, pharmacokinetics and pharmacodynamics of a single administration of BAY 79-4980 compared with standard rFVIII-FS in patients with severe hemophilia A.

METHODS

This randomized, double-blind study consisted of two crossover substudies comparing two doses of liposomal rFVIII-FS with standard rFVIII-FS. Males (12-60 years) with severe hemophilia A received a single infusion of standard rFVIII-FS (35 IU kg(-1)) followed by a single infusion of BAY 79-4980 (13 or 22 mg kg(-1) pegylated liposomes) or vice versa, with 12 observation days and a 2-day washout period between treatments.

RESULTS

Twenty-six subjects were enrolled at two centers. No serious adverse events were reported. Transient increases in complement C3a, but not CH50, were seen in subjects receiving both the low- and high-liposome-dose BAY 79-4980. Mild transient elevations of total and low-density lipoprotein cholesterol were observed. There were no clinically significant differences in clotting or laboratory parameters or in pharmacokinetic behavior between BAY 79-4980 and standard rFVIII-FS. The number of subjects with spontaneous bleeds on days 1-14 postinfusion was low, and group comparisons were inconclusive.

CONCLUSIONS

Single-dose administration of BAY 79-4980 is well tolerated in patients with severe hemophilia A. Plasma pharmacokinetics of FVIII cannot explain the extended protection from bleeding observed previously with BAY 79-4980. Further studies of efficacy and long-term safety of chronic administration are planned.

Computer-assisted learning and simulation lab with 40 DentSim units

There are an increasing number of studies about the computer-assisted dental patient simulator DentSim (DenX, Israel), by which dental students can acquire cognitive motor skills in a multimedia environment. However, only a very few studies have been published dealing with efficient ways to use and to manage a computer-assisted dental simulation lab with 40 DentSim units. The current approach and optimization steps of the College of Dentistry at the University of Tennessee Health Science Center were evaluated based on theoretical and practical tests and by questionnaires (partial 5-point Likert scale). Half of the D1 (first-year) students (2004/05) already had experience with computer-assisted learning at their undergraduate college and most of the students even expected to be taught via computer-assisted learning systems (83.5%) at the dental school. 87.3% of the students working with DentSim found the experience to be very interesting or interesting. Before the students carried out the preparation exercises, they were trained in the skills they needed to work with the sophisticated technology, eg, system-specific operation skills (66.6% attained maximal reachable points) and information searching skills (79.5% attained maximal reachable points). The indirect knowledge retention rate / incidental learning rate of the preparation exercises in the sense of computer-assisted problem-oriented learning regarding anatomy, preparation procedures, and cavity design was promising. The wide- ranging number of prepared teeth needed to acquire the necessary skills shows the varied individual learning curves of the students. The acceptance of, and response to, additional elective training time in the computer-assisted simulation lab were very high. Integrating the DentSim technology into the existing curriculum is a way to improve dental education, but it is also a challenge for both teachers and the students. It requires a shift in both curriculum and instructional goals that have to be reevaluated and optimized continuously.

Safety and pharmacokinetics of a recombinant factor VIII with pegylated liposomes in severe hemophilia A

BACKGROUND

BAY 79-4980 is a sucrose-formulated recombinant factor VIII (rFVIII-FS) combined with pegylated liposomes to prolong activity.

OBJECTIVES

To investigate the safety, tolerability, bioavailability, pharmacokinetics and pharmacodynamics of a single administration of BAY 79-4980 compared with standard rFVIII-FS in patients with severe hemophilia A.

METHODS

This randomized, double-blind study consisted of two crossover substudies comparing two doses of liposomal rFVIII-FS with standard rFVIII-FS. Males (12-60 years) with severe hemophilia A received a single infusion of standard rFVIII-FS (35 IU kg(-1)) followed by a single infusion of BAY 79-4980 (13 or 22 mg kg(-1) pegylated liposomes) or vice versa, with 12 observation days and a 2-day washout period between treatments.

RESULTS

Twenty-six subjects were enrolled at two centers. No serious adverse events were reported. Transient increases in complement C3a, but not CH50, were seen in subjects receiving both the low- and high-liposome-dose BAY 79-4980. Mild transient elevations of total and low-density lipoprotein cholesterol were observed. There were no clinically significant differences in clotting or laboratory parameters or in pharmacokinetic behavior between BAY 79-4980 and standard rFVIII-FS. The number of subjects with spontaneous bleeds on days 1-14 postinfusion was low, and group comparisons were inconclusive.

CONCLUSIONS

Single-dose administration of BAY 79-4980 is well tolerated in patients with severe hemophilia A. Plasma pharmacokinetics of FVIII cannot explain the extended protection from bleeding observed previously with BAY 79-4980. Further studies of efficacy and long-term safety of chronic administration are planned.

Denitrification across landscapes and waterscapes: a synthesis

Denitrification is a critical process regulating the removal of bioavailable nitrogen (N) from natural and human-altered systems. While it has been extensively studied in terrestrial, freshwater, and marine systems, there has been limited communication among denitrification scientists working in these individual systems. Here, we compare rates of denitrification and controlling factors across a range of ecosystem types. We suggest that terrestrial, freshwater, and marine systems in which denitrification occurs can be organized along a continuum ranging from (1) those in which nitrification and denitrification are tightly coupled in space and time to (2) those in which nitrate production and denitrification are relatively decoupled. In aquatic ecosystems, N inputs influence denitrification rates whereas hydrology and geomorphology influence the proportion of N inputs that are denitrified. Relationships between denitrification and water residence time and N load are remarkably similar across lakes, river reaches, estuaries, and continental shelves. Spatially distributed global models of denitrification suggest that continental shelf sediments account for the largest portion (44%) of total global denitrification, followed by terrestrial soils (22%) and oceanic oxygen minimum zones (OMZs; 14%). Freshwater systems (groundwater, lakes, rivers) account for about 20% and estuaries 1% of total global denitrification. Denitrification of land-based N sources is distributed somewhat differently. Within watersheds, the amount of land-based N denitrified is generally highest in terrestrial soils, with progressively smaller amounts denitrified in groundwater, rivers, lakes and reservoirs, and estuaries. A number of regional exceptions to this general trend of decreasing denitrification in a downstream direction exist, including significant denitrification in continental shelves of N from terrestrial sources. Though terrestrial soils and groundwater are responsible for much denitrification at the watershed scale, per-area denitrification rates in soils and groundwater (kg N x km(-2) x yr(-1)) are, on average, approximately one-tenth the per-area rates of denitrification in lakes, rivers, estuaries, continental shelves, or OMZs. A number of potential approaches to increase denitrification on the landscape, and thus decrease N export to sensitive coastal systems exist. However, these have not generally been widely tested for their effectiveness at scales required to significantly reduce N export at the whole watershed scale.

Denitrification across landscapes and waterscapes: a synthesis

Denitrification is a critical process regulating the removal of bioavailable nitrogen (N) from natural and human-altered systems. While it has been extensively studied in terrestrial, freshwater, and marine systems, there has been limited communication among denitrification scientists working in these individual systems. Here, we compare rates of denitrification and controlling factors across a range of ecosystem types. We suggest that terrestrial, freshwater, and marine systems in which denitrification occurs can be organized along a continuum ranging from (1) those in which nitrification and denitrification are tightly coupled in space and time to (2) those in which nitrate production and denitrification are relatively decoupled. In aquatic ecosystems, N inputs influence denitrification rates whereas hydrology and geomorphology influence the proportion of N inputs that are denitrified. Relationships between denitrification and water residence time and N load are remarkably similar across lakes, river reaches, estuaries, and continental shelves. Spatially distributed global models of denitrification suggest that continental shelf sediments account for the largest portion (44%) of total global denitrification, followed by terrestrial soils (22%) and oceanic oxygen minimum zones (OMZs; 14%). Freshwater systems (groundwater, lakes, rivers) account for about 20% and estuaries 1% of total global denitrification. Denitrification of land-based N sources is distributed somewhat differently. Within watersheds, the amount of land-based N denitrified is generally highest in terrestrial soils, with progressively smaller amounts denitrified in groundwater, rivers, lakes and reservoirs, and estuaries. A number of regional exceptions to this general trend of decreasing denitrification in a downstream direction exist, including significant denitrification in continental shelves of N from terrestrial sources. Though terrestrial soils and groundwater are responsible for much denitrification at the watershed scale, per-area denitrification rates in soils and groundwater (kg N x km(-2) x yr(-1)) are, on average, approximately one-tenth the per-area rates of denitrification in lakes, rivers, estuaries, continental shelves, or OMZs. A number of potential approaches to increase denitrification on the landscape, and thus decrease N export to sensitive coastal systems exist. However, these have not generally been widely tested for their effectiveness at scales required to significantly reduce N export at the whole watershed scale.

Expression and localization of VEGF-C and VEGFR-3 in glioblastomas and haemangioblastomas

Primary human brain tumours account for approximately 2% of all cancers. High levels of expression of vascular endothelial growth factor-A (VEGF-A), a potent angiogenic factor, are linked to poor prognosis. In contrast, the potential role in human brain tumour biology of newer VEGF family members, VEGF-C and VEGF-D, both of which are lymphangiogenic factors, is poorly understood. In the present study, the expression of all VEGFs (VEGF-A, -B, -C, and -D) and their receptors (VEGFR-1, -2, and -3) has been assessed in 39 primary human brain tumours. The well-established findings were confirmed with VEGF-A. Surprisingly, however, VEGF-C and VEGF-D, as well as VEGFR-3, were expressed in some tumour types such as haemangioblastomas and glioblastomas, despite their lack of lymphatic vessels. VEGF-C and VEGFR-3 transcripts were localized to the tumour palisade around necrotic areas in glioblastomas and were evenly distributed throughout haemangioblastomas. VEGF-C protein was localized by immunohistochemistry to the palisade layer in glioblastomas. More than 50% of VEGF-C-positive cells also expressed the intermediate-stage inflammatory macrophage marker CD163; however, a significant proportion of VEGF-C-positive cells were CD163-negative. These data demonstrate the presence of molecules, primarily described as regulators of lymphangiogenesis, in normal human brain and brain tumours that are devoid of lymphatics. Their localization in macrophages points to a role in tumour-associated inflammation.

Lymphatic vessel density in the neoplastic progression of Barrett's oesophagus to adenocarcinoma

BACKGROUND

Oesophageal adenocarcinoma is an aggressive neoplasm with poor prognosis as a result of early lymph node metastasis.

AIMS

To measure lymphatic vessel density (LVD) in the neoplastic progression from Barrett's metaplasia to adenocarcinoma and determine whether LVD can predict the risk of cancer. In addition, to correlate LVD with lymph node metastasis and assess whether LVD could be used as a prognostic indicator for outcome or survival.

METHODS

LVD and microvascular density (MVD) were assessed after immunohistochemical staining of vessels in Barrett's metaplasia, dysplasia, and adenocarcinoma tissues and were correlated with clinicopathological features.

RESULTS

LVD was significantly reduced in adenocarcinoma, being half that seen in normal stomach/oesophagus or metaplasia/dysplasia. LVD did not correlate with tumour grade, stage, or clinical outcome; however, patients who had either lymph node metastasis or invasion of tumour cells into peritumorous lymphatic vessels had a significantly worse overall survival. MVD was also assessed as a prognostic marker; its increase appeared to be linked more with the development of Barrett's metaplasia than adenocarcinoma.

CONCLUSIONS

The reduction in lymphatic vessel numbers was not useful for determining disease outcome in the patient group studied. It is the entry of tumour cells into pre-existing peritumorous lymphatic vessels that confers a significantly worse overall survival.

Review of the role of alcohol in drowning associated with recreational aquatic activity

OBJECTIVE AND DESIGN

To assess the role of alcohol in drowning associated with recreational aquatic activity by reviewing the English language literature published up to October 2003.

RESULTS

Alcohol is widely used in association with recreational aquatic activity in the United States, but there is minimal information regarding the extent of use elsewhere. A priori and anecdotal evidence suggests that alcohol is an important risk factor for drowning associated with recreational aquatic activity. Specific studies provide good evidence supporting this, but the extent of increased risk associated with alcohol use, and the attributable risk due to alcohol use, is not well characterised. Drowning appears to be the overwhelming cause of death associated with recreational aquatic activity with alcohol detected in the blood in 30%-70% of persons who drown while involved in this activity. The few relevant studies on degree of increased risk suggest persons with a blood alcohol level of 0.10 g/100 ml have about 10 times the risk of death associated with recreational boating compared with persons who have not been drinking, but that even small amounts of alcohol can increase this risk. The population attributable risk seems to be in the range of about 10%-30%.

CONCLUSIONS

Alcohol consumption significantly increases the likelihood of immersions resulting in drowning during aquatic activities. However, more information is required if appropriate prevention activities are to be planned, initiated, and evaluated. This includes better information on alcohol use, and attitudes to alcohol use, in association with recreational aquatic activity, and the nature and extent of increased risk associated with alcohol use. Evaluation of interventions is also needed.

Use of hand-held laser scanning in the assessment of facial swelling: a preliminary study

A new generation lightweight, hand-held, laser surface scanner (FastSCAN) was validated and clinically evaluated for the assessment of postoperative facial swelling. The potential sources of error-scanner error, registration error, and repositioning and movement error were established for laser scans of a mannequin head and seven volunteers. For the mannequin head the mean (S.D.) volume of the simulated swelling was 12.5 (0.5) cm3. The measurement error was therefore about 4%, and reflected the error in scanned data and in surface registration. Among the volunteers, repositioning of the head introduced additional errors of up to 7.6 cm3 (mean 1.8 cm3), illustrating the additional influence of variable positions. We then scanned 20 patients (9 women and 11 men, age range 18-26) before and 2 days after, third molar removal. The external, facial soft tissue volume changes were calculated for both left and right sides (range 0.2-64.3 cm3). The main source of inaccuracy was again variability of position. Despite this, the FastSCAN proved to be a simple, accurate, and non-invasive method of measuring postoperative changes in volume in the external, soft tissues of the face. Minimising variability in position by using more precise positioning techniques will increase the accuracy of this technique and is a focus for future work.

Crystallization and X-ray diffraction measurements on recombinant molbindin, MopII, from Clostridium pasteurianum

Clostridium pasteurianum carries three genes termed mopI, II and III encoding three molbindin isoforms, one of which has been cloned, the gene product expressed in high yield and crystallized using the hanging-drop vapour-diffusion method. Well ordered monoclinic crystals in two different crystal forms, both with space group C2, were obtained in the presence and absence of Na(2)MoO(4) and Na(2)WO(4). Ligand-bound MopII crystallized with polyethylene glycol (PEG) 400 as a precipitant, whereas apo MopII required PEG 6000. High-resolution diffraction data were collected for ligand-bound MopII structures using synchrotron radiation to 1.8 and 1.6 A resolution for the molybdate and tungstate complexes, respectively. Data were collected on apoMopII crystals to a resolution of 1.8 A in-house.

Home-style beef jerky: effect of four preparation methods on consumer acceptability and pathogen inactivation

The safety of homemade jerky continues to be questioned. Producing a safe product that retains acceptable quality attributes is important. Lethality of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes as well as consumer acceptability and sensory attributes of jerky prepared by four methods were examined. Preparation methods were drying marinated strips at 60 degrees C (representing a traditional method), boiling strips in marinade or heating in an oven to 71 degrees C prior to drying, and heating strips in an oven after drying to 71 degrees C. A 60-member consumer panel rated overall acceptability. A 10-member descriptive panel evaluated quality attributes. Samples heated after drying and samples boiled in marinade prior to drying had slightly higher acceptability scores but were not statistically different from traditional samples. Although the four treatments were significantly different in color (P = 0.0001), saltiness (P = 0.0001), and texture (P = 0.0324), only texture appeared to influence overall consumer acceptability. Microbial challenge studies subjecting the pathogens to the four treatments showed a 5.8-, 3.9-, and 4.6-log reduction of E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, even with traditional drying. Oven treatment of strips after drying was shown to have the potential to reduce pathogen populations further by approximately 2 logs. In conclusion, a safer, yet acceptable home-dried beef jerky product can be produced by oven-heating jerky strips after drying.

The involvement, understanding and attitudes of dietitians towards research and audit

AIM

To investigate the involvement of dietitians in research and audit and to assess their understanding of and attitudes towards these activities.

METHODS

A postal questionnaire was used to investigate the knowledge, attitude towards and involvement in research and audit of State Registered Dietitians practising in the National Health Service (NHS) in the UK.

RESULTS

A response rate of 64% was achieved. Few respondents (15%) were currently involved in research, although more (65%) were currently involved in audit. Involvement in audit rose significantly with increasing grade and managerial responsibility. Dietitians qualifying more recently were more likely to believe that their college training prepared them to undertake research, but felt less confident about undertaking audit. Experience of audit made respondents more confident about auditing their work and improved their belief that they understood audit terminology. Higher grade dietitians were more likely to see audit as an important part of their role than were their more junior colleagues. Understanding of the terms 'research' and 'audit' was poor, although 48% of respondents identified the link between the two activities. Perceived constraints to involvement in research and audit were identified.

CONCLUSION

The present level of involvement of dietitians in research and audit activities falls below that recommended in the BDA's (1997a) National Professional Standards for Dietitians Practising in Healthcare. This study identifies factors that influence dietitians' involvement in, understanding of and attitudes towards research and audit and recommends ways of increasing their involvement in these activities.

Hydrolase and sialyltransferase activities of trypanosoma cruzi trans-sialidase towards NeuAc-alpha-2,3-gal-Gal-beta-O-PNP

NeuAc-alpha-2,3-Gal-beta-O-PNP has been synthesised and its ability to act as a substrate for the hydrolase and transferase activities of Trypanosoma cruzi trans-sialidase have been investigated. The turn-over of this compound shows marked differences from the behaviour of NeuAc-MU. In addition, distinct differences in the action of T. cruzi trans-sialidase and Clostridium perfringens neuraminidase on NeuAc-alpha-2,3-Gal-beta-O-PNP were apparent.

A novel suture anchor of high-density collagen compared with a metallic anchor. Results of a 12-week study in sheep

We report the early mechanical properties and histologic findings of a high-density, type I collagen bone anchor. This new anchor was compared with a traditional metallic anchor in a sheep patellar tendon model. No difference in strength of the repair was noted between the two devices at any time point. The insertions on the repaired side approached the strength of the nonoperated side by 12 weeks. Histologic analysis showed that the collagen anchor integrated with the surrounding bone by 6 weeks, and there was little degradation at 12 weeks. The high-density collagen anchor supported tendon healing to bone comparable with that seen with a traditional metallic device, but it has the potential advantage of the anchor being incorporated into bone.

Tetanus toxin fragment C expressed in live Salmonella vaccines enhances antibody responses to its fusion partner Schistosoma haematobium glutathione S-transferase

Tetanus toxoid has been used widely as an adjuvant. The atoxic fragment C from tetanus toxin (TetC) is potently immunogenic when expressed in Salmonella vaccine strains and has been used as a fusion partner for antigens (Ag). However, there has been no formal comparison of the immunomodulatory impact of TetC on its fusion partners. In this study, we have addressed this important issue. The protective 28-kDa glutathione S-transferase (GST) from Schistosoma haematobium (Sh28GST) was expressed either as a fusion to TetC or as the full-length Sh28GST alone in a nonvirulent aroA-attenuated strain of Salmonella enterica serovar Typhimurium. The Sh28GST proteins were soluble and stably expressed in Salmonella, as evaluated by Western blotting with TetC and/or Sh28GST antisera. Mice were immunized orally with a single dose of the live recombinant Salmonella. The constructs were stable in mice but, dramatically, only the strain expressing the TetC-Sh28GST fusion elicited significant antibody (Ab) responses directed against Sh28GST as determined by enzyme-linked immunosorbent assay. An analysis of the isotype profiles showed that these mice also produced anti-Sh28GST immunoglobulin A and GST-neutralizing assays revealed high levels of neutralizing Abs in sera. These are important correlates of protection in schistosomiasis. In addition, stimulation of spleen cells from immunized mice with Sh28GST Ag showed that both strains, expressing Sh28GST alone or the TetC-Sh28GST fusion, were able to stimulate the secretion of Th1-related cytokines (gamma interferon and interleukin 2) to comparable levels. Thus, TetC has modulated the immune responses generated against its fusion partner, Sh28GST, by markedly enhancing the Ab responses elicited. These results have important implications in the rational development of live vaccines.

The role of the C-terminal domain in the inhibitory functions of tissue factor pathway inhibitor

Tissue factor pathway inhibitor (TFPI) inhibits the activity of coagulation factors VIIa and Xa through Kunitz domains, thereby inhibiting the activity of tissue factor. However, it has been shown that the C-terminal of this inhibitor is essential for the maximal anticoagulant activity of TFPI. We have investigated the endogenous ability of the C-terminal of TFPI to influence coagulation. A synthetic peptide corresponding to residues 254-265 within the C-terminal of TFPI was prepared and shown to be capable of inhibiting tissue factor pathway by preventing the activation of factor VII. Mutational analysis of the peptide revealed the identity of the key lysine residues.

Interleukin 18 contributes to host resistance and gamma interferon production in mice infected with virulent Salmonella typhimurium

Spleen and peritoneal macrophages obtained from innately resistant A/J mice released low levels of interleukin 18 (IL-18) upon infection with Salmonella typhimurium C5 RP4. Incubating the cells with recombinant gamma interferon (rIFN-gamma) enhanced IL-18 production. A/J mice treated in vivo with anti-IL-18 antibodies showed impaired resistance to infection, with increased bacterial loads in the liver and spleen. Administration of rIL-18 could protect A/J mice from challenge with a lethal dose of virulent salmonellae, with a dramatic reduction in bacterial numbers in the tissues. rIL-18 administration did not ameliorate the disease in IFN-gamma-R-/- mice. IL-18 proved to be required for IFN-gamma production by mouse splenocytes from conventional, scid, and rag-1(-/-) mice; in vivo IL-18 neutralization caused a decrease in circulating IFN-gamma levels. Thus, IL-18 is a key factor in early host resistance to Salmonella and probably acts via IFN-gamma.

Interleukin-12 is required for control of the growth of attenuated aromatic-compound-dependent salmonellae in BALB/c mice: role of gamma interferon and macrophage activation

The attenuated S. typhimurium SL3261 (aroA) strain causes mild infections in BALB/c mice. We were able to exacerbate the disease by administering anti-interleukin-12 (IL-12) antibodies, resulting in bacterial counts in the spleens and livers of anti-IL-12-treated mice that were 10- to 100-fold higher than the ones normally observed in premortem mice; yet the animals showed only mild signs of illness. Nevertheless, they eventually died of a slow, progressive disease. Mice infected with salmonellae become hypersusceptible to endotoxin. We found that IL-12 neutralization prevented the death of infected mice following subcutaneous injection of lipopolysaccharide. Granulomatous lesions developed in the spleens and livers of control animals, as opposed to a widespread infiltration of mononuclear cells seen in the organs of anti-IL-12-treated mice. In the latter (heavily infected), salmonellae were seen within mononuclear cells, indicating an impairment of the bactericidal or bacteriostatic ability of the phagocytes in the absence of biologically active IL-12. Gamma interferon (IFN-gamma) levels were reduced in the sera and tissue homogenates from anti-IL-12-treated mice compared to those in control animals. Furthermore, fluorescence-activated cell sorter analysis on spleen cells showed that IL-12 neutralization impaired the upregulation of I-Ad/I-Ed antigens on macrophages from infected mice. Inducible nitric oxide synthase and IFN-gamma mRNA production was down-regulated in anti-IL-12-treated mice, which also showed an increased production of IL-10 mRNA and a decrease in nitric oxide synthase activity in the tissues. Administration of recombinant IFN-gamma to anti-IL-12-treated mice was able to restore host resistance, granuloma formation, and expression of major histocompatibility complex class II antigens in F4/80(+) and CD11b+ spleen cells.

Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

Survival of Escherichia coli O157:H7 in ground beef jerky assessed on two plating media

Recent outbreaks of food-borne illness due to Salmonella spp. in beef jerky and Escherichia coli O157:H7 in venison jerky, coupled with the fact that a variety of preparation methods and dying procedures abound, raise concern over the safety of processed meat products made in the home. The potential of injured bacterial cells to regain the ability to cause illness is a particular threat with pathogens such as E. coli O157:H7, which is believed to have a low infectious dose. This study examined the efficacy of various methods of jerky preparation in reducing populations of E, coli O157:H7 in ground beef jerky and compared the recovery rate of E. coli O157:H7 on two selective plating media, modified sorbitol MacConkey agar (MSMA) and modified eosin methylene blue agar (MEMB). Populations of E. coli O157:H7 in both heated and unheated samples exhibited a greater decline during drying when a nitrite and salt cure mix was added during jerky preparation. When recovery of E. coli O157:H7 on MSMA and MEMB was compared, a trend toward slightly higher recovery rates with MEMB was observed. On the basis of these results, MEMB is a suitable alternative to MSMA for the recovery of E. coli O157:H7 from heated and dried meat samples similar to beef jerky.

Expression and immunogenicity of an Echinococcus granulosus fatty acid-binding protein in live attenuated Salmonella vaccine strains

Fatty acid-binding proteins (FABPs) are candidate molecules for vaccines against several parasitic platyhelminths. A FABP from the cestode Echinococcus granulosus (EgDf1) was expressed in Salmonella vaccine strains as a C-terminal fusion to fragment C of tetanus toxin (TetC) by using expression vector pTECH. The fusion protein was equally expressed in several attenuated vaccine strains derived from bacteria with different genetic backgrounds and different attenuating mutations. Single-dose immunization experiments with the aroA Salmonella typhimurium strain SL3261 carrying the pTECH-EgDf1 construct were conducted with mice, using both the intravenous and the oral routes. Surprisingly, the antibody response to EgDf1 and the antigen-specific cytokine production in spleen cells were stronger in mice immunized orally. Furthermore, immune mouse sera strongly reacted with fixed sections of the worm's larval stage. Analysis of the isotype distribution of the specific anti-EgDf1 antibodies showed similar production of immunoglobulin G1 (IgG1) and IgG2a together with specific IgA antibodies. In addition, stimulation of spleen cells from mice immunized with the different constructs with either Salmonella lysate, TetC, or EgDf1 showed that, together with Th1-related cytokines (gamma interferon and interleukin 2 [IL-2]), significant levels of a Th2 cytokine (IL-5) were produced specifically, indicating a Th2 component to the response to the Salmonella carrier and to the recombinant antigens. Salmonellae expressing the TetC-rEgDfl fusion are currently under evaluation as potential vaccines against E. granulosus.

Correlates of protection induced by live Aro- Salmonella typhimurium vaccines in the murine typhoid model

Live attenuated salmonella vaccines generally confer better protection than killed vaccines. The immune responses in BALB/c mice elicited by immunization with a live attenuated Aro Salmonella typhimurium vaccine given orally, intravenously or subcutaneously were compared with those elicited by killed whole-cell vaccines (acetone or heat-treated) given subcutaneously. Live vaccines given by all routes elicited higher interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) responses in spleen cells against an alkali-treated whole-cell salmonella lysate than did killed vaccines. Live and killed vaccines elicited high total antibody levels to smooth lipopolysaccharide (LPS) (enzyme-linked immunosorbent assay), but all live vaccine regimes elicited higher IgG2a, suggesting a Th1 response. Oral and intravenous vaccination with live organisms elicited IgA against smooth LPS which subcutaneous vaccination with live or killed salmonellae failed to evoke. Western blots using rough whole-cell lysates showed that all vaccines elicited a varied anti-protein response; however, all groups immunized with live organisms recognized three unidentified bands of MW 52,000, 46,000 and 18,000 which were consistently absent in groups immunized with killed organisms. The results indicate that immunization with live aroA salmonellae elicited a Th1 type of response, including bystander T-cell help to LPS, and a response to proteins not seen in mice that received killed vaccines.

Induction of human factor VIII inhibitors in rats 2: Fine mapping of rat anti-human rFVIII antibodies

Inhibiting antibodies in patients with hemophilia A pose a significant therapeutic dilemma in the treatment of bleeding episodes. The genetic factors which predispose hemophiliacs to inhibitors and the optimal method for inhibitor suppression remain obscure. Hence, an animal model of the human FVIII inhibitor response is of potential value. Sprague-Dawley rats immunized with human recombinant FVIII (rFVIII) subsequently developed abnormal coagulation parameters coincident with the development of an immune response to the human protein. The epitopes for the resultant rat anti-rFVIII antibodies were mapped using a random fragment expression library constructed from the FVIII cDNA. Antigenic regions located within the A1, First and Second Acidic and B domains were mapped. Rat immunoglobulins reactive with the individual epitopes were immunoaffinity purified and assayed for inhibitory activity. Several of the epitopes mapped using the rat antibodies were similar to regions previously shown to be antigenic for human inhibitors. By contrast, no epitopes were mapped to the A2 domain with the techniques used. This may be due to the possible presence of conformational epitopes in this area which cannot undergo fragmentation and still retain antigenicity or the presence of relatively low concentrations of antibodies to this region. The rat model shares some similarity with both the auto- and alloimmune human response to FVIII and therefore may be a valuable model for studies on the induction and suppression of the inhibitor response.

Down-regulation of hormone-sensitive lipase in sterol ester-laden J774.2 macrophages

The development of atherosclerotic plaques in arteries is a key step in atherogenesis, with cholesterol ester accumulation in macrophage-derived foam cells being recognized as a major pathogenic event in this process. In this study, the mouse macrophage cell line J774.2 was induced to accumulate intracellular sterol esters by incubation with 25-hydroxycholesterol in the presence of oleic acid. The accumulation of sterol esters in these cells was found to be accompanied by a marked decrease in the activity of the enzyme responsible for their hydrolysis, namely hormone-sensitive lipase (HSL); Western blotting studies revealed a corresponding decrease in the levels of the HSL polypeptide. Similar findings were obtained after incubation with oxidized low-density lipoprotein or very-low-density lipoprotein. These findings suggest that down-regulation of the expression of HSL is important in cholesterol ester accumulation in macrophages.

Prosthodontic management of a combination transosteal/endosteal implant reconstruction: a clinical report

This is a clinical report of a patient who was not referred for prosthodontic evaluation and treatment until after undergoing Bränemark endosseous implant placement to supplement the previously existing mandibular staple bone plate implant. This supplemental treatment was the surgeon's attempt to resolve the patient's complaint of loose dentures. Creativity with implant biomechanics and prosthodontic design were necessary to restore the patient, in a predictable manner, to normal function. A fixed, detachable cast overdenture bar rigidly connected to all the implants was constructed utilizing resilient attachments to retain the tissue-supported mandibular overdenture. A presurgical prosthodontic evaluation could have averted many of the problems encountered with treatment. More effective conventional prosthodontic treatment may have resolved the patient's complaints and eliminated the need for additional implant placement.

Protection against oral challenge three months after i.v. immunization of BALB/c mice with live Aro Salmonella typhimurium and Salmonella enteritidis vaccines is serotype (species)-dependent and only partially determined by the main LPS O antigen

The role of the main LPS O antigen in the specificity of protection as mediated by systemic mechanisms following immunization with live attenuated Aro Salmonella vaccines was studied in mice. Innately Salmonella-susceptible (Itys) BALB/c mice were immunized intravenously with a single dose of either Salmonella typhimurium SL3261 aroA (LPS O4,5,12) or Salmonella enteritidis Se795aroA (LPS O1,9,12), and challenged orally 2-3 months later with either S. typhimurium C5 or S. enteritidis Thirsk. Nearly isogenic transductants of the two challenge strains expressing either their own LPS or that of the other serotype (S. typhimurium C5 O4 or O9, and S. enteritidis Thirsk O9 or O4) were also used. Both vaccines conferred similar high protection against the virulent strain of the homologous serotype expressing its own LPS. There was no protection against the heterologous serotype expressing its own LPS. However, when vaccinated mice were challenged with either the same serotype as the vaccine but expressing the heterologous LPS, or with the heterologous serotype expressing the LPS of the vaccine, protection was always lower than protection against the fully homologous serotype. Anti-smooth LPS antibodies showed higher titres against the homologous LPS, but with significant crossreactivity with the heterologous LPS. Antibodies to O-rough S. typhimurium and S. enteritidis LPS were present following immunization with either of the two vaccine strains. The LPS alone cannot fully account for the specificity of protection in this model; other (protein) antigens may be responsible. It remains to be seen whether there is a T-cell mediated component to the specificity of protection conferred by live Salmonella vaccines.

Induction of human factor VIII inhibitors in rats by immunization with human recombinant factor VIII: a small animal model for humans with high responder inhibitor phenotype

Hemophilia A is a clotting disorder that is due to reduced or absent coagulation factor VIII (FVIII) activity. In approximately 25% of people with severe hemophilia A, standard treatment with intravenous plasma-derived or recombinant FVIII (rFVIII) induces anti-FVIII antibodies that inhibit FVIII activity (inhibitors). We describe the development of a rat model to study the formation of inhibitors. Immunization of rats with human rFVIII in adjuvant induced an anti-human rFVIII antibody response characteristic of an anti-FVIII inhibitor response in hemophilia A patients. The rats exhibited a rapid, polyclonal secondary antibody response to human rFVIII. These antibodies were reactive against epitopes located in the heavy and light chains. All the rFVIII-immunized rats developed antibodies against the FVIII C2 domain, a region of major reactivity in hemophilia A patients with inhibitors. Furthermore, competition ELISAs demonstrated that rat and human anti-FVIII antibodies recognized identical or overlapping epitopes of the FVIII molecule. The rat anti-FVIII antibodies also functioned as human FVIII inhibitors with titers ranging from 120 to 2048 Bethesda Units (B.U.). We propose that this rat model may be useful to investigate immune responses to FVIII and may lead to better therapies for FVIII inhibitors.

Effect of interleukin 12 neutralization on host resistance and gamma interferon production in mouse typhoid

Innately resistant (Ityr) A/J mice infected with the virulent Salmonella typhimurium C5 strain suppress the early exponential bacterial growth in the reticuloendothelial system toward the end of the first week of infection, with spleen and liver bacterial counts reaching a plateau phase. In vivo administration of neutralizing anti-interleukin-12 (IL-12) antibodies did not affect early bacterial growth in the tissues (days 1 to 3) but impaired the establishment of the plateau, with higher spleen and liver counts by day 7 of the infection in anti-IL-12 treated mice than in untreated controls. Gamma interferon (IFN-gamma) was detectable in the sera and spleen homogenates of both control and anti-IL-12-treated mice on days 3 and 7 of the infection. Noticeably, IFN-gamma levels were significantly lower in anti-IL-12 treated mice than in control animals. Splenocytes from uninfected A/J mice released IFN-gamma in response to concanavalin A (ConA) or to S. typhimurium C5. In vitro IL-12 neutralization dramatically impaired the IFN-gamma response to S. typhimurium but not to ConA. Splenocytes harvested from infected anti-IL-12 treated mice on day 7 of the infection produced significantly lower amounts of IFN-gamma upon in vitro stimulation with ConA and with a Salmonella protein-rich extract than did cells from similarly infected untreated control animals. Spleen cells from infected mice showed lower proliferative (mitogenic) responses to ConA and to a Salmonella soluble extract than did cells from uninfected mice. In vivo anti-IL-12 treatment significantly restored the ability of splenocytes from infected mice to proliferate in response to the antigens and ConA. In vivo neutralization of IL-12n in innately susceptible BALB/c mice ((ItyS)) immunized with a live attenuated aromatic-dependent Salmonella vaccine reduced host resistance to virulent oral challenge with S. typhimurium C5. Thus, in primary Salmonella infections, IL-12 mediates the suppression of growth of virulent salmonellae in the reticuloendothelial system, positively modulates IFN-gamma production, and is involved in the immunosuppression which accompanies the acute stages of the disease. IL-12 also contributes to host resistance to virulent organisms in secondary infections.

The unidentified interstellar infrared bands: PAHs as carriers?

Infrared emission spectra of gas-phase naphthalene and pyrene have been measured in the range of 3 to 7.5 micrometers with ultraviolet laser desorption-excitation and a spectroscopic technique featuring single-photon counting in the infrared. The spectra were compared with the unidentified infrared emission bands that are observed in many astronomical objects. Marked discrepancies between those observations and the laboratory emission spectra in the wavelengths and relative intensities of principal spectral features led to the conclusion that small neutral unsubstituted polycyclic aromatic hydrocarbons cannot be the carriers of the unidentified infrared emission bands.

Role of hns in the virulence phenotype of pathogenic salmonellae

A TnphoA-generated mutant C5060, attenuated for virulence, was derived from the mouse-virulent Salmonella typhimurium strain C5. This mutation, designated hns-112::TnphoA, harbours the transposon in the 3' end of hns, with the alkaline phosphatase open reading frame in the opposite orientation to that of hns. Bacterial strains harbouring hns-112::TnphoA were mucoid and had altered levels of DNA supercoiling, as monitored using pUC18 as a reporter plasmid. Transduction of hns-112::TnphoA into mouse virulent strains, including S. typhimurium SL1344 and Salmonella enteritidis Se795, resulted in attenuation. When an independent hns mutation, harbouring a kanamycin-resistance cassette inserted into the Kpnl site at base pair 237 of the hns gene, was introduced into S. typhimurium C5, the isolates were also attenuated. S. typhimurium C5 isolates harbouring the multicopy plasmid pGB651, which encodes the Escherichia coli hns gene, were partially attenuated in mice. Transductional analysis, using Tn10 insertions located close to the hns gene, showed that virulence could be restored in genetic crosses that eliminated the resident hns mutations. However, some hns+ transductants were still attenuated, suggesting that secondary attenuating lesions can accumulate in hns-deficient strains. These studies show that the hns locus plays a role in Salmonella virulence.

Toxicity of lipopolysaccharide and of soluble extracts of Salmonella typhimurium in mice immunized with a live attenuated aroA salmonella vaccine

Mice immunized intravenously 10 days earlier (but not those immunized 2 months earlier) with an attenuated Salmonella typhimurium SL3261 aroA live vaccine and tested for delayed-type hypersensitivity by injection of crude Salmonella extracts in the footpad can die within 24 to 48 h of an unexplained allergic reaction. The lethal reaction could be prevented by prior administration of anti-tumor necrosis factor alpha serum. Injection of lipopolysaccharide (LPS) (either purified phenol-water-extracted [Westphal] LPS or protein-rich trichloracetic acid-extracted [Boivin] LPS) was also lethal for mice immunized 10 days before. An LPS-rich crude Salmonella extract was more toxic than one which contained less LPS, suggesting that LPS may have been involved in the lethal reactions to crude antigens. Mild alkaline hydrolysis removes O-linked acyl groups from lipid A and eliminates many toxic effects of LPS; however, both Boivin LPS and Westphal LPS remained toxic for immunized mice after alkaline hydrolysis. In contrast, alkaline hydrolysis of crude whole Salmonella extracts (which caused marked protein degradation) reduced the lethal toxicity of the extracts, especially for an LPS-rich preparation. Mice immunized orally with the live vaccine did not show hypersensitivity to either LPS or crude extracts. The results suggest that the lethal reaction to crude Salmonella antigens in mice immunized 10 days earlier is complex, that tumor necrosis factor alpha is involved, and that allergic reactions to crude antigens (but not to LPS alone) can be reduced by mild alkaline hydrolysis.

Use of seeded Nd:YAG lasers for high-resolution spectroscopy

The frequency tuning and stabilization of a novel long-pulse seeded Nd:YAG laser is described. The laser frequency was stabilized to +/-8 MHz by locking it to an iodine absorption. A Doppler-free experiment shows the laser linewidth to be in good agreement with the Fourier transform limit of 10 MHz. Molecular hyperfine frequencies and parameters were determined for three I(2) absorption lines. The use of this laser as a pump and a cw probe amplifier for coherent anti-Stokes Raman spectroscopy is illustrated by a scan of the 2v(2)Q-branch transition in CO(2), and the instrumental resolution is found to be 43 +/- 15 MHz.