Specific detection of prion antigenic determinants retained in bovine meat and bone meal by flow microbead immunoassay

AIMS

The purpose of this study was to develop an effective method for detecting prion (PrP) antigenic determinants remaining in bovine meat and bone meal (MBM) using pressurized fluid extraction (PSE) equipment and flow microbead immunoassay (FMI).

METHODS AND RESULTS

Using the FMI, bovine recombinant PrP could be determined quantitatively in the 7 pmol-7 nmol range using anti-PrP peptide polyclonal antibody-coupled microbeads and anti-PrP monoclonal antibody (SAF61) as a detection antibody. PSE extraction at 120 degrees C for 5 min under high pressure was most effective for eluting PrP determinants from bovine MBMs. The FMI was capable of detecting PrP determinants in bovine MBM extracts with high specificity and indicated that the MBMs contained high levels of PrP determinants. This assay was also applied to the detection of PrP(Sc) determinants in bovine MBM spiked with a scrapie-infected brain at a weight ratio of 50 : 1.

CONCLUSIONS

These data indicate that this assay was effective for the specific detection of PrP determinants contained in bovine MBM extracts.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first report detailing the detection of PrP determinants in bovine MBM. The assay could be applied to securing the safety of bovine MBM.

Phase II study of gefitinib for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) gene mutations detected by PNA-LNA PCR clamp

7076

Background: The responsiveness to gefitinib has been reported to closely link to the presence of EGFR gene mutations. We developed a method, PNA-LNA PCR clamp, capable of detecting EGFR mutations in the presence of 100-fold background of wild type EGFR from normal cells (Can Res. 2005;65:7276). This study was prospectively designed to evaluate 1) the sensitivity and the specificity of the PNA-LNA PCR clamp (sample size > 100 pts) and 2) a phase II study of gefitinib for NSCLC patients (pts) with EGFR gene mutations (sample size > 25 pts to show the lower limit of 95% CI > 50%). Methods: Clinical samples (sputum, pleural effusion, bronchial fluid and paraffin tissue) were obtained from consecutive NSCLC pts with informed consent in our institution, and were tested by the PNA-LNA PCR clamp. After the second informed consent, for PS 0–2, inoperable stage III and IV pts with EGFR mutations, gefitinib (250mg P.O. daily) was given as the second treatment after docetaxel containing chemotherapy. In case of poor PS pts, the first line chemotherapy was omitted. Results: From Sept. ’04 to Oct. ’05, samples from 100 of a total of 107 pts were informative of EGFR mutation status. PNA-LNA PCR clamp detected EGFR mutations in 38 pts (38%) (15 males/23 females; median age:62; adenoca.:33 pts). Exon 19 deletions, L858R and L861Q were found in 25 (66%), 12 (32%) and 1 (2%) patients, respectively. But 62 pts (51 males/11 females; median age:66; Ad:43 pts) were judged to have wild type EGFR. Between positive and negative pts in EGFR mutation, there was significant difference in the distinction of sex (p = 0.00001). Gefitinib was given to 26 pts with EGFR mutations as the first line (4 pts) or the second line treatment (22 pts). One patient and 20 patients showed CR and PRs, respectively, and the response rate was 81% (95% CI: 61–94%). For patients with wild EGFR genes, gefitinib was given to 5 patients and one patient (20%) showed PR. The response rate was significantly different between wild and mutant EGFR genes detected by the PNA-LNA PCR clamp (p = 0.017). Conclusions: PNA-LNA PCR clamp could reliably detect EGFR mutations, indicating the method is useful to detect EGFR mutations in clinical specimens. Updated data will be presented at the meeting.

No significant financial relationships to disclose.

Balloon Test Occlusion with Perfusion CT Imaging Utilizing Intraarterial Contrast Injection

SUMMARY

Balloon Test Occlusion (BTO) is performed to evaluate the collateral flow when a permanent therapeutic occlusion of unilateral carotid artery is planned. BTO with neurological evaluation alone, however, has a rather high false negative rate. In order to improve the sensitivity, several adjunctive procedures such as induced hypotension or cerebral blood flow (CBF) measurement with various modalities have been combined. Perfusion CT (PCT) is another imaging modality that is mainly used for the diagnosis of acute stroke. In this study, we evaluate the efficacy and the safety of BTO combined with PCT in the same procedure utilizing intraarterial contrast injection from the catheter. Seven patients underwent BTO with PCT in our institution. All the procedures were performed in the angio/CT combination suite. BTO was performed in the usual fashion and when the patient passed the 30 minutes' BTO clinically, PCT was performed subsequently. Contrast material was injected from a Pig Tail catheter placed in the ascending aorta. The obtained data were transferred to a workstation and perfusion maps of CBF, cerebral blood volume (CBV), and time to peak (TTP) were generated using software. In three patients, single photon emission CT (SPECT) was also obtained with administering 99 mTc-ethyl cysteinate dimer (99 mTc-ECD) intravenously during BTO. Although all the patients had passed the BTO clinically, the CBF maps of three patients revealed significant decrease in the occluded hemisphere. There was no procedure-related morbidity. PCT using intraarterial contrast injection during BTO was performed successfully and safely. Intraarterial injection allowed us to obtain excellent time-attenuation curves by utilizing less contrast material and less radiation doze.

Efficacy of 3-D Reconstructed Time of Flight MRA Follow-up of the Embolized Cerebral Aneurysms

SUMMARY

A follow-up of the embolized cerebral aneurysm with Guglielmi Detachable Coils (GDC) were performed mainly using craniograms and digital subtraction angiograms (DSA) so far.Recently, several authors have reported about efficacy of the time of flight (TOF) magnetic resonance angiogram (MRA) as a follow-up for the embolized cerebral aneurysms. In our institution, 3-D reconstructed TOF MRAs have been performed as a follow-up of the embolized cerebral aneurysms.We examined efficacy of 3-D reconstructed TOF MRA. 3-D TOF MRA was performed for a followup of the embolized cerebral aneurysms at our outpatient clinic in 35 patients. Morphological examination of the 3-D images between 3-D TOF MRA and 3-D DSA was performed. Almost similar images of 3-D MRA were obtained after 3-D reconstruction as compared with those of 3-D DSA. In three cases, recanalization was suspected in the 3-D TOF MRA. And recanalization was confirmed in the 3-D DSA actually. A quality of 3-D TOF MRA for a diagnosis of recanalization was good and practical. However, in two cases, arteries were partially disappeared in the 3-D TOF MRA.These were the artifact due to coil mass and this is a current limitation of 3-D TOF MRA. The images of 3-D TOF MRA that were reconstructed in the 3-D workstation were very similar to those of 3-D DSA. 3-D reconstructed TOF MRA was very useful for a less-invasive diagnosis of a recanalization of the embolized cerebral aneurysms.

Thromboembolic Events during Endovascular Coil Embolization of Cerebral Aneurysms

SUMMARY

Thromboembolic events was most important adverse event for coil embolization for intracerebral aneurysm. The present study investigated possible risk factors for thromboembolic events during coil embolization using diffusion-weighted imaging (DWI), comparing unruptured and ruptured lesions.

Endovascular treatment of experimental cerebral aneurysms using thermoreversible liquid embolic agents

SUMMARY

We have developed a new embolic agent, thermoreversible gelation polymer (TGP). This polymer is unique in that solidification occurs at body temperature. The utility of this new liquid embolic agent for the treatment of large experimental aneurysms was evaluated angiographically. TGP remains liquid at temperatures below the sol-gel transition temperature (TT) and becomes gelatinous above the TT. TGP can also be used to slowly deliver biologically active substances such as growth factors or engineered cells. In this study, TGP was mixed with radiopaque material without solvent. Bilateral common carotid arteries of swine (n=5) were used for surgical creation of lateral aneurysms, then 1 aneurysm in each animal was embolized using TGP without any protection device. The remaining untreated aneurysm in each animal was used as a control. All aneurysms were successfully embolized using TGP. No distal migration of TGP was observed when aneurysms were embolized without using protection devices. TGP can be safely used to embolize experimental aneurysms. Embolization of aneurysms with a protection device needs to be evaluated. Further modifications such as mechanical stability and use as a drug delivery system will be necessary prior to the clinical application of TGP.

Therapeutic management of cerebral arteriovenous malformations. Present role of interventional neuroradiology

This chapter summarizes the authors' experience in the endovascular therapy of cerebral arteriovenous malformations (AVMs). This clinical series includes 660 patients treated from 1980 to 2005. The first 148 patients were treated at University Hospital, in London, Ontario Canada, in association with Drs. Allan Fox, Dave Pelz, John Girvin and Charles Drake. The next 512 patients were treated at UCLA Medical Center, Los Angeles, California in association with Drs. Gary Duckwiler, Reza Jahan, Jacques Dion, Pierre Gobin, Neil Martin and John Frazee. Only patients treated with superselective endovascular/intraoperative catheterization and embolization of avm arterial feeders were included. Cerebral arteriovenous malformations treated by non-selective injection of beads in ICA or vertebral arteries were excluded. Modern neuroimaging modalities associated to the anatomical, topographic and functional evaluations of cerebral avms such as brain CT and CTA, MRI, MRA and functional MRI are all utilized at UCLA Medical Center. They have become essential in the therapeutic management of avms closely related to cerebral eloquent areas (figure 1).

Microstructures and bond strengths of plasma-sprayed hydroxyapatite coatings on porous titanium substrates

Hydroxyapatite (HA) coating was carried out by plasma spraying on bulk Ti substrates and porous Ti substrates having a Young's modulus similar to that of human bone. The microstructures and bond strengths of HA coatings were investigated in this study. The HA coatings with thickness of 200-250 microm were free from cracks at interfaces between the coating and Ti substrates. XRD analysis revealed that the HA powder used for plasma spraying had a highly crystallized apatite structure, while the HA coating contained several phases other than HA. The bond strength between the HA coating and the Ti substrates evaluated by standard bonding test (ASTM C633-01) were strongly affected by the failure behavior of the HA coating. A mechanism to explain the failure is discussed in terms of surface roughness of the plasma-sprayed HA coatings on the bulk and porous Ti substrates.

Production of adiponectin, an anti-inflammatory protein, in mesenteric adipose tissue in Crohn's disease

BACKGROUND AND AIMS

A characteristic feature of Crohn's disease (CD) is mesenteric adipose tissue hypertrophy. Mesenteric adipocytes or specific proteins secreted by them may play a role in the pathogenesis of CD. We recently identified adiponectin as an adipocyte specific protein with anti-inflammatory properties. Here we report on expression of adiponectin in mesenteric adipose tissue of CD patients.

METHODS AND RESULTS

Mesenteric adipose tissue specimens were obtained from patients with CD (n = 22), ulcerative colitis (UC) (n = 8) and, for controls, colon carcinoma patients (n = 28) who underwent intestinal resection. Adiponectin concentrations were determined by enzyme linked immunosorbent assay, and adiponectin mRNA levels were determined by real time quantitative reverse transcription-polymerase chain reaction. Tissue concentrations and release of adiponectin were significantly increased in hypertrophied mesenteric adipose tissue of CD patients compared with normal mesenteric adipose tissue of CD patients (p = 0.002, p = 0.040, respectively), UC patients (p = 0.002, p = 0.003), and controls (p<0.0001, p<0.0001). Adiponectin mRNA levels were significantly higher in hypertrophied mesenteric adipose tissue of CD patients than in paired normal mesenteric adipose tissue from the same subjects (p = 0.024). Adiponectin concentrations in hypertrophied mesenteric adipose tissue of CD patients with an internal fistula were significantly lower than those of CD patients without an internal fistula (p = 0.003).

CONCLUSIONS

Our results suggest that adipocytes in hypertrophied mesenteric adipose tissue produce and secrete significant amounts of adiponectin, which could be involved in the regulation of intestinal inflammation associated with CD.

Role of helper T cells in the humoral immune responses against 53-kDa outer membrane protein from Porphyromonas gingivalis

Outer membrane protein with a 53-kDa molecular weight (Ag53) isolated from Porphyromonas gingivalis evokes strong humoral immune responses in many periodontitis patients. To examine the effects of cytokines produced by Ag53-specific Th cells on the IgG production against Ag53, we established Ag53-specific Th-cell lines from patients with early onset periodontitis and from healthy volunteers. We then developed a mixed lymphocyte culture system between Ag53-specific Th cells and auto- or allo-derived T-cell-depleted leukocytes produced from the subjects whose HLA class II haplotypes were completely matched. Interferon-gamma production was observed in all Th cell lines from patients and healthy subjects. As for Th2 type cytokines, interleukin (IL)-4, IL-5, IL-6 and IL-10 production varied greatly in Th cells regardless of the periodontal condition of the donor. Only Th cell lines with a high Th2/Th1 ratio induced Ag53-specific IgG production when cocultured with T-cell-depleted leukocytes. Thus, the difference in Th2/Th1 balance may regulate the Ag53-specific IgG production.

Multiple cystic cavernous angiomas associated with hemorrhage

A 29-year-old man presented with impaired mental concentration and inability to remember. Magnetic resonance and computed tomography studies revealed multiple calcified cysts. Craniotomy was performed and one of the lesions was resected. The histological diagnosis was cavernous angioma. The first report of multiple cystic cavernous angiomas is reported.

Identification of genes differentially regulated in rat alveolar bone wound healing by subtractive hybridization

Periodontal healing requires the participation of regulatory molecules, cells, and scaffold or matrix. Here, we hypothesized that a certain set of genes is expressed in alveolar bone wound healing. Reciprocal subtraction gave 400 clones from the injured alveolar bone of Wistar rats. Identification of 34 genes and analysis of their expression in injured tissue revealed several clusters of unique gene regulation patterns, including the up-regulation at 1 wk of cytochrome c oxidase regulating electron transfer and energy metabolism, presumably occurring at the site of inflammation; up-regulation at 2.5 wks of pro-alpha-2 type I collagen involving the formation of a connective tissue structure; and up-regulation at 1 and 2 wks and down-regulation at 2.5 and 4 wks of ubiquitin carboxyl-terminal hydrolase l3 involving cell cycle, DNA repair, and stress response. The differential expression of genes may be associated with the processes of inflammation, wound contraction, and formation of a connective tissue structure.

Prevalence of periodontal bacterial infection in non-obese Japanese type 2 diabetic patients: relationship with C-reactive protein and albuminuria

The aim of the present study was to investigate the relationship between periodontal bacteria infection ( Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedius) and C-reactive protein (CRP) and albuminuria in non-obese Japanese type 2 diabetic patients. One hundred and thirty-four non-obese Japanese type 2 diabetic patients without evidence of current acute illness including clinically significant acute infectious disease were enrolled into the study. The degree of periodontal bacterial infection was evaluated using IgG titer against Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, or Prevotella intermedius. The bacterial sonic extracts were used as antigens. High-sensitivity CRP (hCRP), glucose, glycosylated hemoglobin (HbA (1c)), and lipids were also measured after an overnight fast. Urinary albumin excretion rate as a ratio of urinary albumin and urinary creatinine was assessed in a morning spot urine sample using a commercial enzymatic immunoassay. The prevalence of Porphyromonas gingivalis infection was 52.2 % and that of Actinobacillus actinomycetemcomitans and Prevotella intermedius was 7.5 and 14.2 %, respectively. IgG titer against Porphyromonas gingivalis significantly correlated with CRP (r = 0.225, p < 0.001) and albuminuria (r = 0.185, p < 0.05), while IgG titer against Actinobacillus actinomycetemcomitans or Prevotella intermedius was not associated with either parameter. These results suggest that among periodontal bacteria, Porphyromonas gingivalis infection is associated with atherosclerosis in non-obese Japanese type 2 diabetic patients.

Application of denaturing gradient gel electrophoresis (DGGE) to the analysis of microbial communities of subgingival plaque

OBJECTIVES

Denaturing gradient gel electrophoresis (DGGE) was applied to the microbiologic examination of subgingival plaque.

MATERIALS AND METHODS

The PCR primers were designed from conserved nucleotide sequences on 16S ribosomal RNA gene (16SrDNA) with GC rich clamp at the 5'-end. Polymerase chain reaction (PCR) was performed using the primers and genomic DNAs of typical periodontal bacteria. The generated 16SrDNA fragments were separated by denaturing gel.

RESULTS

Although the sizes of the amplified DNA fragments were almost the same among the species, 16SrDNAs of the periodontal bacteria were distinguished according to their specific sequences. The microflora of clinical plaque samples were profiled by the PCR-DGGE method, and the dominant 16SrDNA bands were cloned and sequenced. Simultaneously, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia were detected by an ordinary PCR method. In the deep periodontal pockets, the bacterial community structures were complicated and P. gingivalis was the most dominant species, whereas the DGGE profiles were simple and Streptococcus or Neisseria species were dominant in the shallow pockets. The species-specific PCR method revealed the presence of A. actinomycetemcomitans, P. gingivalis and P. intermedia in the clinical samples. However, corresponding bands were not always observed in the DGGE profiles, indicating a lower sensitivity of the DGGE method.

CONCLUSION

Although the DGGE method may have a lower sensitivity than the ordinary PCR methods, it could visualize the bacterial qualitative compositions and reveal the major species of the plaque. The DGGE analysis and following sequencing may have the potential to be a promising bacterial examination procedure in periodontal diseases.

Gene profiling in human periodontal ligament fibroblasts by subtractive hybridization

Genes expressed by human periodontal ligament fibroblasts (HPFs) are likely to be associated with specific functions of the ligament. The aim of this study is to profile genes expressed highly by HPFs. A library (6 x 10(3) pfu) was constructed, followed by subtraction of HPF cDNAs with human gingival fibroblast (HGF) cDNAs. Reverse-dot hybridization revealed that 33 clones expressed higher levels of specific mRNAs in HPFs than in HGFs. These were mRNAs for known genes, including several associated with maturation and differentiation of cells. None had been reported in PFs. One clone, PDL-29, identified as a COX assembly factor, showed much stronger mRNA expression in HPFs than in HGFs in culture. In rat periodontium, however, PDL-29 mRNA expression was similar in PFs and GFs. These results suggest that HPFs express many previously unreported genes associated with maturation and differentiation, but expression can differ in vitro and in vivo.

Sequence diversity in the major fimbrial subunit gene (flp-1) of Actinobacillus actinomycetemcomitans

Cells of the periodontal pathogen Actinobacillus actinomycetemcomitans exhibit tight adherence to surfaces such as glass, plastic and hydroxyapatite, a property that probably plays an important role in the ability of this bacterium to colonize teeth and other surfaces. Tight adherence is mediated by long fibrils of bundled pili (fimbriae) that form on the surface of the cell. The flp-1 gene encodes the major pilin protein component of A. actinomycetemcomitans fimbriae. In this study we compared flp-1 DNA sequences from 43 strains of A. actinomycetemcomitans isolated in Europe, Japan and the United States and identified seven distinct flp-1 allelic classes. DNA and predicted protein sequences were almost completely conserved within each flp-1 class but were highly divergent between classes. Most amino acid substitutions occurred in the C-terminus of the pilin protein, a region that has been shown to be important for the bundling and adhesive properties of the pili. flp-1 classes correlated with serotypes and 16S rRNA genotypes in most strains. At least five strains showed evidence of horizontal transfer of flp-1 between strains of different serotypes and 16S rRNA genotypes. Four of the seven flp-1 classes were present in geographically diverse isolates. Strains representing all seven flp-1 classes, but not a strain carrying a transposon insertion in flp-1, bound avidly to polystyrene in an in vitro adherence assay. Strains representing six of the seven flp-1 classes were isolated from localized juvenile periodontitis patients, suggesting that phylogenetically diverse strains carry pathogenic potential. Our findings provide a framework for future biochemical, immunological and genetic studies of A. actinomycetemcomitans fimbriae.

Enhanced macrophage responsiveness to lipopolysaccharide and CD40 stimulation in a murine model of inflammatory bowel disease: IL-10-deficient mice

OBJECTIVE

To elucidate the role of macrophages in the pathogenesis of inflammatory bowel disease, proinflammatory characteristics of macrophages were estimated in a murine model of spontaneous intestinal inflammation.

MATERIALS AND METHODS

Peritoneal macrophages from IL-10deficient mice were stimulated with lipopolysaccharide (LPS) or an anti-CD40 monoclonal antibody (mAb). Cytokine release was assessed by enzyme-linked immunosorbent assay. CD40 expression was examined by two-color flow cytometric analysis. Induction of suppressor of cytokine signaling 3 (SOCS3) mRNA was evaluated by real-time quantitative RT-PCR.

RESULTS

In the presence of LPS or anti-CD40 mAb, TNF-alpha and IL-12p70 release from macrophages of mutant mice was significantly higher than that from macrophages of wild-type mice. This may be due to the difference in IL-10 production by macrophages, since activated macrophages of wild-type mice produced IL-10 in amounts sufficient to suppress an increased release of cytokines from activated macrophages of mutant mice. LPS and CD40 stimulation induced significantly high level of SOCS3 expression in macrophages of mutant mice in comparison to those of wild-type mice.

CONCLUSIONS

Macrophages from a murine model of inflammatory bowel disease demonstrated enhanced responsiveness to immunological and bacterial stimuli. This suggests significant roles of macrophages in the pathogenesis of inflammatory bowel disease.

Characterization of two genes encoding ferritin-like protein in Actinobacillus actinomycetemcomitans

Two genes encoding ferritin-like protein, designated afnA and afnB, were identified in the upstream region of actX on the Actinobacillus actinomycetemcomitans chromosomal DNA. The actX has been reported to be a regulatory gene homologous to the Escherichia coli fnr, which controls the growth and virulence of A. actinomycetemcomitans under anaerobic conditions. The afnB located 340 bp-upstream from the actX, and the afnA located just 15 bp-upstream from afnB. The afnA and afnB encoded 161 and 165 amino acid residues, respectively, which were similar to ferritin-like proteins of other microorganisms. Western immunoblotting using rabbit antiserum against E. coli ferritin showed these two proteins, which are reactive with the serum with 19-kDa molecular masses, are produced from A. actinomycetemcomitans. The N-terminal amino acid sequences of the two proteins were consequent with those deduced from afnA and afnB. Northern hybridization revealed that the afnA and afnB constituted a bicistronic operon and the accumulation of afnA and afnB mRNA was upregulated under aerobic conditions. These findings suggested that the operon was regulated by the presence of oxygen. The two ferritin-like proteins may have important roles in the adaptation of A. actinomycetemcomitans to oxidative environmental changes.

Intraaneurysmal flow dynamics study featuring an acrylic aneurysm model manufactured using a computerized tomography angiogram as a mold

OBJECT

To obtain precise flow profiles in patients' aneurysms, the authors developed a new in vitro study method featuring an aneurysm model manufactured using three-dimensional computerized tomography (3D CT) angiography.

METHODS

A clear acrylic basilar artery (BA) tip aneurysm model manufactured from a patient's 3D CT angiogram was used to analyze flow modifications during one cardiac cycle. Stereolithography was utilized to create the aneurysm model. Three-dimensional flow profiles within the aneurysm model were obtained from velocity measurements by using laser Doppler velocimetry. The aneurysm inflow/outflow zones changed dynamically in their location, size of their cross-sectional area, and also in their shapes over one cardiac cycle. The flow velocity at the inflow zone was 16.8 to 81.9% of the highest axial velocity in the BA with a pulsatility index (PI) of 1.1. The flow velocity at the outflow zone was 16.8 to 34.3% of the highest axial velocity of the BA, with a PI of 0.68. The shear stress along the walls of the aneurysm was calculated from the fluid velocity measured at a distance of 0.5 mm from the wall. The highest value of shear stress was observed at the bleb of the aneurysm.

CONCLUSIONS

This clear acrylic model of a BA tip aneurysm manufactured using a CT angiogram allowed qualitative and quantitative analysis of its flow during a cardiac cycle. Accumulated knowledge from this type of study may reveal pertinent information about aneurysmal flow dynamics that will help practitioners understand the relationship among anatomy, flow dynamics, and the natural history of aneurysms.