bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of a new enzyme‐linked immunosorbent assay for detection of total hepatitis C virus core antigen in blood donors
Authors: Cano H. , Candela M. J. , Lozano M. L. , Vicente V.
Published: November 2003

Summary.  Recent studies have shown that total hepatitis C virus (HCV) core antigen, both free and antibody bound, is an accurate indirect marker of viral replication that can be used in clinical practice. The aim of the present study was to evaluate the performance of a new total HCV core antigen enzyme‐linked immunosorbent assay (ELISA) for detection and quantification of total core antigen in blood donors, testing positive for anti‐HCV antibodies and for prospective low‐risk population screening.

A population comprising 257 samples, from blood donors detected reactive for anti‐HCV antibodies [137 recombinant immunoblot assay (RIBA) positive and 120 RIBA indeterminate], were tested by using a new total HCV core antigen ELISA. HCV‐RNA was quantified by using quantitative polymerase chain reaction (PCR) assays in all RIBA‐positive samples and RIBA‐indeterminate samples that were positive for the total core antigen. Specificity of the assay was studied in 1070 healthy blood donors negative for anti‐HCV antibodies.

Compared with quantitative PCR assays, the total HCV core antigen assay showed 97·37% sensitivity. The three HCV‐RNA‐positive samples, which tested negative for the total core antigen, had a low viral load (<1·4 × 104 IU mL−1). All samples with more than 1·4 × 104 IU mL−1 of viral RNA were positive for total core antigen, independent of the HCV genotype. Concentration of total core antigen correlated significantly with those of HCV‐RNA (r = 0·614, P < 0·0001). Overall specificity in freshly collected blood donor specimens was 99·63%.

Our data indicate that the total HCV core antigen ELISA has a sensitivity close to PCR assays in diagnosing HCV infection in blood donors with anti‐HCV antibodies and shows an excellent specificity in volunteer donors. This assay, in combination with anti‐HCV antibodies screening tests, could be an alternative to molecular assays for HCV infection screening in blood donors.
Serological findings amongst first‐time blood donors in Yaoundé, Cameroon: is safe donation a reality or a myth?
Authors: Mbanya D. N. , Takam D. , Ndumbe P. M.
Published: November 2003

Summary.  Blood safety remains an issue of major concern in transfusion medicine in developing countries where national blood transfusion services and policies, appropriate infrastructure, trained personnel and financial resources are lacking. This is aggravated by the predominance of family and replacement, rather than regular benevolent, nonremunerated donors. Thus, in order to identify and encourage healthy, regular and benevolent nonremunerated donors, consenting first‐time blood donors in the Yaoundé University Teaching Hospital were screened for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBSAg), hepatitis C virus (HCV), human T‐cell lymphotropic virus‐I (HTLV‐I) and syphilis using standard methods. Of 252 first‐time donors recruited, 66 (26·2%) were positive for at least one of the infections screened. There were 7·9% positive for HIV, 10·7% for HBSAg, 4·8% for HCV and 9·1 and 1·6%, respectively, for syphilis and HTLV‐I. About 30% of the 66 infected persons had co‐infections. HIV‐positive donors had a significantly increased risk of being positive for antibodies to syphilis (OR = 7·27; 95% CI = 2·23–23·51; P = 0·0007), not observed for HBV, HCV and HTLV‐I. These results suggest that blood transfusion is still very unsafe in this community and that it is imperative that emphasis be laid on donor education. Furthermore, donors with a history of sexually transmitted infections should be totally excluded from all donations.
Effect of haemodilution with diaspirin cross‐linked haemoglobin on the oxygen reserve in a rodent model of surgical blood loss
Authors: D'Almeida M. S. , White M. , Martin C. M. , Sibbald W. J. , Chin‐Yee I. H.
Published: November 2003

Summary.  The efficacy of pre‐operative haemodilution is limited by the reduction in haemoglobin concentration. Acellular haemoglobin‐based oxygen carriers provide an alternative to colloid as a haemodiluent, potentially extending the safe limits of this procedure. The aim of this investigation was to determine whether haemodilution with a cross‐linked haemoglobin solution, diaspirin cross‐linked haemoglobin solution (DCLHb), would enhance the oxygen reserve compared to pentastarch.

Sprague Dawley rats were placed in a metabolic box to directly measure systemic oxygen consumption (VO2). Rats were randomized to be haemodiluted to a cellular haemoglobin of 80 g L−1 with either DCLHb or pentastarch. Oxygen reserve was assessed during isovolemic haemorrhage by determining the critical oxygen delivery (DO2crit) and haemoglobin concentration at the point of oxygen supply dependency (OSD).

Following haemodilution and for the duration of the experiment, cardiac index (CI) was significantly lower and systemic vascular resistance was significantly higher in the DCLHb than the pentastarch group. The DO2crit (3·2 ± 0·4 mL minAg−1 and 3·4 ± 0·5 mL minAg−1, DCLHb versus pentastarch) and cellular haemoglobin concentration (51 ± 9 g L−1 and 48 ± 9 g L−1), at which rats entered OSD were similar in both groups. Total haemoglobin concentration (cellular and plasma DCLHb) and arterial oxygen content were significantly higher in the DCLHb group (total haemoglobin, 66 ± 8 g L−1 and arterial content, 9·2 ± 1·4 mL dL−1) compared to the pentastarch group (total haemoglobin, 48 ± 9 g L−1 and arterial content, 7·3 ± 1·4 mL dL−1). Oxygen extraction ratios increased from baseline levels to 0·53 ± 0·07 and 0·56 ± 0·1, for the DCLHb and pentastarch groups, respectively, and were not significantly different.

The increase in arterial oxygen content from DCLHb in plasma was offset by the decrease in CI observed in this group. Plasma DCLHb did not extend the limits of haemodilution beyond the capacity of the cellular haemoglobin concentration.
Haemolytic disease of the newborn due to maternal irregular antibodies in the Chinese population in Taiwan
Authors: Wu K. H. , Chu S. L. , Chang J. G. , Shih M. C. , Peng C. T.
Published: November 2003

Summary.  From 1991 to 2000, amongst 23 886 full‐term healthy Chinese babies delivered at our hospital, 2615 babies developed neonatal hyperbilirubinaemia. After excluding other causes of hyperbilirubinaemia and identifying the irregular antibodies, 15 cases of haemolytic disease of the newborn (HDN) due to maternal irregular antibodies were diagnosed; three cases were born in our hospital and 12 cases were referred. Amongst these 15 babies, six cases had HDN due to anti‐E, three cases due to anti‐E + c, three cases due to anti‐D, one case due to anti‐c and two cases due to ‘Mi’ antibodies reacting with MiIII phenotype cells (anti‐Hil and anti‐Mur). Although there were four cases of hydrops fetalis, only one of the patients expired.

The prevalence of HDN caused by maternal irregular antibodies has been estimated to be 0·01%. Therefore, routine prenatal screening for irregular antibodies was not rational in the Chinese population in Taiwan. Anti‐E and anti‐E + c were the important irregular antibodies resulting in HDN. Although few cases of HDN due to anti‐‘Mi’ have been reported, Anti‐‘Mi’ is significant in regions with a high prevalence of the MiIII phenotype.
Variability in standard care for cytomegalovirus prevention and detection in pediatric lung transplantation: Survey of eight pediatric lung transplant programs
Authors: Danziger‐Isakov Lara A. , Faro Albert , Sweet Stuart , Michaels Marian G. , Aurora Paul , Mogayzel Peter J. , Mallory George B. , Boyer Debra M. , Rice Tom B. , DelaMorena Maite , DeBaun Michael R. ,   the International Pediatric Lung Transplant Collaborative Group
Published: November 2003

Abstract:  Cytomegalovirus (CMV) infection after pediatric lung transplantation is a significant risk factor for morbidity and mortality in the first year after transplantation. Multiple strategies have been reported for CMV prevention among adult lung transplant programs. In contrast, little information has been reported regarding protocols for prevention and detection of CMV from pediatric programs. We conducted a survey to better understand the range of practice patterns for CMV prevention and detection at pediatric lung transplant centers. A self‐administered questionnaire was distributed to 11 pediatric lung transplant centers identified through the International Pediatric Lung Transplant Collaborative in September 2002. A member of the lung transplant team from each institution was asked to provide the methods of CMV prevention and surveillance. Eight of 11 centers surveyed responded to the questionnaire accounting for 45.6% (26 of 57) and 100% (three of three) of the pediatric lung transplants performed in the US and UK in 2001, respectively. All centers used prophylactic therapy against CMV with either ganciclovir or valganciclovir with duration ranging from 3.5 wk to indefinitely. Most centers (six of eight) prescribed a prophylactic regimen based on donor and recipient CMV serostatus. Half (four of eight) of the centers report using CMV hyperimmune globulin in addition to an antiviral agent. Method for CMV detection varied widely, including use of conventional viral culture (n = 1), antigenemia (n = 7), and polymerase chain reaction (n = 2). A wide range of strategies is used to prevent and detect CMV in pediatric lung transplant recipients with little empiric evidence demonstrating the optimal approach. A retrospective analysis among these centers is being conducted to evaluate the efficacy of these approaches.
Outcome after renal transplantation in children: Results of follow‐up by nephrologists in a primary referral center
Authors: Adedoyin Olanrewaju , Frank Rachel , Vento Suzanne , Vergara Marcela , Gauthier Bernard , Trachtman Howard
Published: November 2003

Abstract:  Pediatric patients who receive a kidney transplant require extended follow‐up to monitor graft function and for management of complications. Because of convenience, most patients are sent back to the nephrologists who referred them for transplantation (the primary nephrologist) for long‐term care. As a consequence, many pediatric nephrologists who provide this extended care are not associated with a transplant center. It is not known if this arrangement yields satisfactory outcomes for children and adolescents who receive a kidney transplant.

The objective was to determine if clinical outcomes are satisfactory in pediatric renal transplant recipients who were followed up by their primary nephrologists after the procedure. A chart review was carried out on all renal transplant recipients seen in the renal clinic at Schneider Children's Hospital (SCH) from 1982 to 2001. Patients were eligible if they were followed up by the primary referring nephrologists at SCH for a minimum of 6 months after transplantation. Relevant demographic and clinical outcome data were compiled. Twenty‐eight patients who received a total of 33 renal allografts [living related donors (LRD) 15 and cadaveric donors (CD) 18] were seen during the study period. The transplantations in 19 children (68%) were carried out at Montefiore Hospital (Bronx, NY, USA), while the rest were performed at other centers. There were three (11%) deaths, two LRD patients and one CD patient. The group of 25 surviving patients consisted of 17 males and eight females, age range 4–28 yr (mean 17.2 yr). The mean duration of renal allograft survival was 6.3 ± 5.3 yr and the mean duration of follow‐up was 6.1 ± 5.3 yr. The most recent serum creatinine ranged from 0.5 to 3.8 mg/dL with a mean of 1.3 ± 0.8 mg/dL. There were several complications including acute rejection, renal artery stenosis, and hydronephrosis in the allograft. The team of primary referring nephrologists successfully treated all of these except the child with hydronephrosis. The primary nephrologist who refers pediatric patients to a tertiary care transplant center can accomplish long‐term follow‐up of renal transplant recipients after discharge from the transplant center. The clinical outcomes are acceptable and compare favorably with the results described in the literature that have been achieved in patients followed up at transplant centers. Problems rarely developed that required referral back to the transplant center for management. This approach to care is recommended because it is more likely to foster compliance by both patients and parents.
Characterizing T‐cell receptor γ‐variable gene in Aotus nancymaae owl monkey peripheral blood
Authors: Guerrero J.E. , Pacheco D.P. , Suárez C.F. , Martínez P. , Aristizabal F. , Moncada C.A. , Patarroyo M.E. , Patarroyo M.A.
Published: November 2003

Abstract:  γδ T lymphocytes have a heterodimeric complex formed by the association of γ and δ chains as receptor. Proliferation of this lymphocyte population has been observed, when infection by several pathogens such as Mycobacterium tuberculosis and Plasmodium spp. occurs. The New World Monkey Aotus nancymaae has become a very good experimental model for the immunological and physiopathological study of these infectious agents. The A. nancymaaeγ‐variable region was characterized from peripheral blood samples by using cDNA and genomic DNA polymerase chain reaction amplification, DNA sequencing, and dot‐blot hybridization techniques. Seventeen different T‐cell receptor γ‐variable (TCRGV) sequences were obtained. These sequences were distributed among TCRGV subsets 1, 2, or 3, according to human subset classification. Although no subset 4 amplification was obtained, this subset was detected by dot‐blot hybridization. The presence of these 4 subsets resembles the behavior displayed by ‘γδ‐low species’ (humans and mice), where high diversity among these lymphocytes can be observed. Homologies greater than 70% were found with respect to humans. Sequence convergence between human and A. nancymaae subsets 1 and 3 highlights Aotus as a promising model for studying these lymphocyte functions.
Detailed analysis of the effects of Glu/Lys β69 human leukocyte antigen‐DP polymorphism on peptide‐binding specificity
Authors: Berretta F. , Butler R.H. , Diaz G. , Sanarico N. , Arroyo J. , Fraziano M. , Aichinger G. , Wucherpfennig K.W. , Colizzi V. , Saltini C. , Amicosante M.
Published: November 2003

Abstract:  The polymorphism at position β69 of the human leukocyte antigen (HLA)‐DP molecule has been associated with susceptibility to several immune disorders and alloreactivity. Using molecular modeling, we have predicted a detailed structure of the HLA‐DP2 molecule (carrying Gluβ69) complexed with class II associated invariant chain derived peptide (CLIP) and compared it with the form carrying Lys at β69 (HLA‐DP2K69). Major changes between the two models were observed in the shape and charge distribution of pocket 4 and of the nearby pocket 6. Consequently, we analyzed in detail the peptide‐binding specificities of both HLA‐DP molecules expressed as recombinant proteins. We first determined that the minimum peptide‐binding core of CLIP for both HLA‐DP2 and DP2K69 is represented by nine aminoacids corresponding to the sequence 91–99 of invariant chain (Ii). We then assessed the peptide‐binding specificities of the two pockets and determined the role of position β69, using competition tests with the Ii‐derived peptide CLIP and its mutated forms carrying all the aminoacidic substitutions in P4 and P6. Pocket 4 of HLA‐DP2 showed high affinity for positively charged, aromatic, and polar residues, whereas aliphatic residues were disfavored. Pocket 4 of the DP2K69 variant showed a reduced aminoacid selectivity with aromatic residues most preferred. Pocket 6 of HLA‐DP2 showed high affinity for aromatic residues, which was increased in DP2K69 and extended to arginine. Finally, we used the experimental data to determine the best molecular‐modeling approach for assessing aminoacid selectivity of the two pockets. The results with best predictive value were obtained when single aminoacids were evaluated inside each single pocket, thus, reducing the influence of the overall peptide/ major histocompatibility complex interaction. In conclusion, the HLA‐DPβ69 polymorphism plays a fundamental role in the peptide‐binding selectivity of HLA‐DP. Furthermore, as this polymorphism is the main change in the pocket 4 area of HLA‐DP, it could represent a supertype among HLA‐DP molecules significantly contributing to the selection of epitopes presented in the context of this HLA isotype.
Two subtypes of hepatitis B virus‐associated glomerulonephritis are associated with different HLA‐DR2 alleles in Koreans
Authors: Park M.H. , Song E.Y. , Ahn C. , Oh K.‐H. , Yang J. , Kang S.J. , Lee H.S.
Published: November 2003

Abstract:  Hepatitis B virus (HBV)‐associated glomerulonephritis (HBV‐GN) is occurring at high prevalence in most Asian endemic areas. There have been some reports on human leucocyte antigen (HLA) associations with HBV infections; however, HLA association with HBV‐GN has been rarely reported. Forty‐six adult Korean patients with HBV‐GN (42 male and four female patients, age 20–66), 100 HBsAg (–) healthy controls, and 89 individuals with chronic HBV infection were studied for HLA‐DRB1 and DQB1 gene polymorphisms using high‐resolution DNA typing methods. In HBV‐GN patients, a strong association with HLA‐DR2 was observed compared with HBsAg (–) controls (OR = 4.0). Different HLA‐DR2 alleles were associated with different pathologic subtypes of HBV‐GN: DRB1*1502 with membranoproliferative glomerulonephritis (MPGN, n = 35) (OR = 14.5) and DRB1*1501 with membranous nephropathy (MN, n = 11) (OR = 3.8). HLA‐DQB1*0601, strongly linked to DRB1*1502, was also associated with MPGN subtype of HBV‐GN (OR = 4.3). All these associations were also significant compared with chronic HBV infection group. For chronic HBV infection per se, DRB1*1302, DQB1*0402, and DQB1*0604 had some protective effect (OR = 0.4, OR = 0.3, and OR = 0.1, respectively), and DRB1*1101 was weakly associated (OR = 4.6) in Koreans. These results suggest that HLA‐DR or related genetic factor is associated with disease susceptibility to HBV‐GN in Koreans, and different pathologic subtypes of HBV‐GN are influenced by the genetic factors of the patients.
Chronic beryllium disease: immune‐mediated destruction with implications for organ‐specific autoimmunity
Authors: Fontenot A.P. , Kotzin B.L.
Published: November 2003

Abstract:  Chronic beryllium disease (CBD) is caused by exposure to beryllium in the workplace and is characterized by an accumulation of beryllium‐specific CD4+ T cells with granulomatous inflammation in the lung. Owing to its unique physical properties, beryllium is used in a variety of high‐technology industries, and CBD continues to be an important public health concern. CBD develops in up to 16% of exposed workers, depending on genetic susceptibility and the nature of the exposure. Increased susceptibility has been associated with particular HLA‐DP alleles, especially those possessing negatively charged residues at certain positions of the peptide‐binding pocket. The mechanism for this disease association lies in the ability of certain HLA‐DP molecules, with associated peptides, to bind and present beryllium to pathogenic CD4+ T cells. In patients with CBD, large numbers of effector memory CD4+ T cells are compartmentalized to the lung, and these cells are poised to release T helper 1‐type cytokines upon beryllium recognition. In the same patients, however, beryllium‐specific T cells are barely detectable in the circulation. As opposed to those present in blood, beryllium‐specific cells in the lung no longer require the engagement of CD28 for optimal T‐cell activation and in fact frequently lose the expression of CD28. These findings in CBD have important implications for studies in autoimmune diseases, including those in which the antigen is unknown and the target organ is inaccessible.
The significance of a defect on DMSA scan in children with renal transplants
Authors: Hutchinson C. , Beckett M. , Kiratli P. , Gordon I , Trompeter R. S. , Rees L.
Published: November 2003

Abstract:  Since December 1995, pediatric renal transplant recipients in our unit have received a DMSA scan as soon as possible post‐transplant in order to provide a baseline for comparison in the event of subsequent complications.

We retrospectively reviewed the case notes and DMSA scans of the 45 patients who underwent a scan within 9 wk of their transplant to see if pre or peri‐transplant factors or post‐transplant complications were associated with defects on scanning. Forty percentage of scans had defects. The presence of defects was not associated with potential predisposing factors such as patient or donor age, cadaveric or live donation, cold ischemia time, multiple donor vessels, the use of non‐heart beating donors, the mean time to scan, the serum creatinine, or the presence of structural renal tract anomalies predisposing to UTI. However, 87% of patients had complications before the scan, including UTI, rejection, acute tubular necrosis, transplant biopsy and drug toxicity.

Children with no clinical complications had a significantly reduced risk of a defect (p = 0.035), while biopsy was associated with the presence of defects (p = 0.0034). Twenty patients had one or more follow up DMSA scans: one patient developed a new focal defect. In conclusion, renal transplant defects are frequently found on DMSA scanning even early after transplantation and are non‐specifically associated with many different complications.
Sensitivity to Hsp90‐targeting drugs can arise with mutation to the Hsp90 chaperone, cochaperones and plasma membrane ATP binding cassette transporters of yeast
Authors: Piper Peter W. , Millson Stefan H. , Mollapour Mehdi , Panaretou Barry , Siligardi Giuliano , Pearl Laurence H. , Prodromou Chrisostomos
Published: November 2003

The Hsp90 molecular chaperone catalyses the final activation step of many of the most important regulatory proteins of eukaryotic cells. The antibiotics geldanamycin and radicicol act as highly selective inhibitors of in vivo Hsp90 function through their ability to bind within the ADP/ATP binding pocket of the chaperone. Drugs based on these compounds are now being developed as anticancer agents, their administration having the potential to inactivate simultaneously several of the targets critical for counteracting multistep carcinogenesis. This investigation used yeast to show that cells can be rendered hypersensitive to Hsp90 inhibitors by mutation to Hsp90 itself (within the Hsp82 isoform of yeast Hsp90, the point mutations T101I and A587T); with certain cochaperone defects and through the loss of specific plasma membrane ATP binding cassette transporters (Pdr5p, and to a lesser extent, Snq2p). The T101I hsp82 and A587T hsp82 mutations do not cause higher drug affinity for purified Hsp90 but may render the in vivo chaperone cycle more sensitive to drug inhibition. It is shown that these mutations render at least one Hsp90‐dependent process (deactivation of heat‐induced heat shock factor activity) more sensitive to drug inhibition in vivo.
Molecular cloning and functional expression of the human sodium channel β1B subunit, a novel splicing variant of the β1 subunit
Authors: Qin Ning , D'Andrea Michael R. , Lubin Mary‐Lou , Shafaee Navid , Codd Ellen E. , Correa Ana M.
Published: November 2003

The voltage gated sodium channel comprises a pore‐forming α subunit and regulatory β subunits. We report here the identification and characterization of a novel splicing variant of the human β1 subunit, termed β1B. The 807 bp open reading frame of the human β1Β subunit encodes a 268 residue protein with a calculated molecular mass of 30.4 kDa. The novel human β1B subunit shares an identical N‐terminal half (residues 1–149) with the human β1 subunit, but contains a novel C‐terminal half (residues 150–268) of less than 17% sequence identity with the human β1 subunit. The C‐terminal region of the human β1B is also significantly different from that of the rat β1A subunit, sharing less than 33% sequence identity. Tissue distribution studies reveal that the human β1Β subunit is expressed predominantly in human brain, spinal cord, dorsal root ganglion and skeletal muscle. Functional studies in oocytes demonstrate that the human β1B subunit increases the ionic current when coexpressed with the tetrodotoxin sensitive channel, NaV1.2, without significantly changing voltage dependent kinetics and steady‐state properties, thus distinguishing it from the human β1 and rat β1A subunits.
Efficient synthesis of a disulfide‐containing protein through a batch cell‐free system from wheat germ
Authors: Kawasaki Takayasu , Gouda Mudeppa D. , Sawasaki Tatsuya , Takai Kazuyuki , Endo Yaeta
Published: November 2003

We have developed a highly productive cell‐free protein synthesis system from wheat germ, which is expected to become an important tool for postgenomic research. However, this system has not been optimized for the synthesis of disulfide‐containing proteins. Thus, we searched here for translation conditions under which a model protein, a single‐chain antibody variable fragment (scFv), could be synthesized into its active form. Before the start of translation, the reducing agent dithiothreitol, which normally is added to the wheat germ extract but which inhibits disulfide formation during translation, was removed by gel filtration. When the scFv mRNA was incubated with this dithiothreitol‐deficient extract, more than half of the synthesized polypeptide was recovered in the soluble fraction. By addition of protein disulfide isomerase in the translation solution, the solubility of the product was further improved, and nearly half of the soluble polypeptides strongly bound to the antigen immobilized on an agarose support. This strong binding component had a high affinity as shown by surface‐plasmon resonance analysis. These results show that the wheat germ cell‐free system can produce a functional scFv with a simple change of the reaction ingredients. We also discuss protein folding in this system and suggest that the disulfide bridges are formed cotranslationally. Finally, we show that biotinylated scFv could be synthesized in similar fashion and immobilized on a solid surface to which streptavidin is bound. SPR measurements for detection of antigens were also possible with the use of this immobilized surface.
Undergraduate nursing student experience
Authors: Magnussen Lois , Amundson Mary Jane
Published: November 2003

Abstract  The purpose of the present qualitative study was to describe and explicate the experience of being a nursing student. A convenience sample of 12 nursing students from a variety of backgrounds at a public university were interviewed using an interview guide with open‐ended questions. Their stories provided an insight into the satisfactions, challenges and stresses faced by students. Four major theme clusters emerged from the data: (i) meeting conflicting demands; (ii) feeling overworked; (iii) feeling unprepared and; (iv) seeking respect and support from one's faculty. These identified themes corroborate the findings of other researchers who have studied the student experience. Student's stories provide insights into the current educational environment, which can assist faculties to understand the impact of their pedagogical approaches. This information is particularly important in light of the current worldwide nursing shortage.
Construction and identification of a recombinant live attenuated Salmonella typhimurium vaccine strain carrying Helicobacter pylori heat shock protein subunit B gene
Authors: LI Guo Qing , CHEN Min Hu , JIAO Zhi Yong , ZHU Sen Lin , CHEN Jie , HU Pin Jin
Published: November 2003

OBJECTIVE:  Because Helicobacter pylori is the principal cause of chronic active gastritis and peptic ulcer disease, the present study explored the possibility of constructing a recombinant live attenuated S. typhimurium vaccine strain carrying H. pylori heat shock protein subunit B (HspB) gene.

METHODS:  A 1640‐bp HspB gene was cloned into a prokaryotic expression plasmid pTrc99A. After sequence analysis, the result was compared with the sequence of H. pylori‐HspB gene and protein provided by the Genebank using BLAST analysis. The identified recombinant plasmid was then introduced into a live attenuated S. typhimurium strain SL3261.

RESULTS:  Using polymerase chain reaction (PCR) and restriction enzyme digestion, a recombinant pro­karyotic expression plasmid pTrc99A‐HspB harboring the HspB gene was constructed and successfully introduced into a live attenuated S. typhimurium strain SL3261. Most of the H. pylori‐HspB in the recombinant plasmid pTrc99A‐HspB was consistent with the H. pylori‐HspB sequence provided by the Genebank. The exchange of A/T or C/G in the cloned sequence hardly changed the encoded amino acids; the homology for both the genes and proteins of H. pylori SS1 strain was 97%; the homology with other common H. pylori strains J99 and 26695 was 96% for both.

CONCLUSION:  A recombinant live attenuated S. typhimurium vaccine strain harboring H. pylori‐HspB gene was successfully constructed and verified, which may help in the development of an oral vaccine against H. pylori infection.
Different T helper type immune responses induced by Helicobacter pylori vaccine in mouse model
Authors: CHEN Jie , CHEN Min Hu , LI Guo Qing , JIAO Zhi Yong , YU Jun , LIANG Wei Qiang , CHEN Wei , HU Pin Jin , SHEN Zu Yao
Published: November 2003

OBJECTIVE:  To study the protective immune response induced by Helicobacter pylori vaccine in mice.

METHODS:  Mice were orally immunized with cholera toxin (CT) plus H. pylori whole‐cell sonicate antigen (group A), CT only (group B) or normal saline (group C), and challenged with H. pylori 4 weeks later. Mice from each group were killed at different time points before and after challenge. Gastric H. pylori colonization, serum anti‐H. pylori IgG1, IgG2a and IgA antibodies, the mRNA expression of both Th1‐type and Th2‐type cytokines in the gastric mucosa and splenic tissue, and mucosal inflammation at different time points were compared among the groups.

RESULTS:  Colonization of H. pylori in group A decreased significantly compared with groups B and C at both 5 and 26 weeks after challenge. The serum concentrations of anti H. pylori IgG1, IgG2a and IgA in group A were significantly higher than those of groups B and C at all time points. The mRNA expressions of Th1‐type cytokines in the gastric mucosa of groups A and B were higher than those of group C both before and 5 weeks after H. pylori challenge. At 26 weeks after challenge, Th1‐type cytokines were increased in the gastric mucosa of group C, but decreased in the gastric mucosa of groups A and B, except for IL‐12. Before challenge, Th2‐type cytokines were expressed at a similar level in the gastric mucosa of both group A and group B; 5 weeks after challenge, IL‐4 and IL‐10 expressions were not detectable in either group and the expression of IL‐6 in both groups was lower than that in group C; 26 weeks after challenge, the expression of both IL‐4 and IL‐10 was detected in group A, but only IL‐10 in group B. The expression of IL‐6 was similar in all groups. Both Th1‐ and Th2‐type cytokines were expressed in the splenic tissue of all groups at different time points. Significant gastritis characterized by marked infiltration of mononuclear cells and neutrophils was found in group A at 5 weeks after challenge, but only mild inflammation was present in group B; 26 weeks after challenge, gastritis had increased in group C but decreased in the other two groups.

CONCLUSIONS:  The vaccine consisting of H. pylori whole‐cell sonicate antigen and CT induces both Th1 and Th2 immune responses at an early stage. The Th1 response increases early after H. pylori challenge, which contributes to both protective immunity and postimmunization gastritis, whereas the Th2 response increases in the gastric mucosa late after challenge when both the Th1 response and postimmunization gastritis have abated.
Decreased iNOS synthesis mediates dexamethasone‐induced protection of neurons from inflammatory injury in vitro
Authors: Golde Sabine , Coles Alasdair , Lindquist Jonathan A. , Compston Alastair
Published: November 2003

Brain inflammation is accompanied by transection of axons and death of neurons in the acute lesions of multiple sclerosis. We explored mechanisms of inflammatory damage to neurons in vitro using cocultures of rat embryonal cortical neurons with microglia activated by interferon‐gamma (IFNγ) and lipopolysaccharide (LPS). Previously, we have demonstrated that microglia are highly toxic to neurons and that nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) is necessary and sufficient to mediate this toxicity. Here, we show that addition of dexamethasone (1 µM) to activated cocultures provides effective neuroprotection. We demonstrate that dexamethasone down‐regulates NO production of primary microglia by ≈ 50% and reduces steady‐state iNOS protein and mRNA expression by ≈ 70%. These changes were reversed by the glucocorticoid receptor blocker RU‐486. Furthermore, we analysed the stability of iNOS protein and show that whilst inhibitors of the proteasome blocked iNOS degradation they did not reverse the dexamethasone effect. Our results indicate that the main mechanism of corticosteroid activity on iNOS is reduction in protein synthesis, not destabilization as previously suggested.
Effect of NT‐4 and BDNF delivery to damaged sciatic nerves on phenotypic recovery of fast and slow muscles fibres
Authors: Simon Magda , Porter Rebecca , Brown Robert , Coulton Gary R. , Terenghi Giorgio
Published: November 2003

We investigated whether neurotrophin‐4 (NT‐4) and brain‐derived neurotrophic factor (BDNF) affected the reinnervation of slow and fast motor units. Neurotrophin‐impregnated or plain fibronectin (FN) conduits were inserted into a sciatic nerve gap. Fast extensor digitorum longus (EDL) and slow soleus muscles were collected 4 months postsurgery. Muscles were weighed and fibre type proportion and mean fibre diameters were derived from muscle cross‐sections. All fibre types in muscles from FN animals were severely atrophied and this correlated well with type 1 fibre loss and atrophy in soleus and type 2b loss and atrophy in EDL. Treatment with NT‐4 reversed soleus but not EDL mass loss above the FN group by significantly restoring type 1 muscle fibre proportion and diameters towards those of normal unoperated animals. BDNF did not increase muscle mass but did have minor effects on fibre type and diameter. Thus, NT‐4 significantly improved slow motor unit recovery, and provides a basis for therapies intended to aid the functional recovery of muscles after denervating injury.
Restricted daily consumption of a highly palatable food (chocolate Ensure®) alters striatal enkephalin gene expression
Authors: Kelley A. E. , Will M. J. , Steininger T. L. , Zhang M. , Haber S. N.
Published: November 2003

Brain opioid peptide systems are known to play an important role in motivation, emotion, attachment behaviour, the response to stress and pain, and the control of food intake. Opioid peptides within the ventral striatum are thought to play a key role in the latter function, regulating the affective response to highly palatable, energy‐dense foods such as those containing fat and sugar. It has been shown previously that stimulation of mu opiate receptors within the ventral striatum increases intake of palatable food. In the present study, we examined enkephalin peptide gene expression within the striatum in rats that had been given restricted daily access to an energy‐dense, palatable liquid food, chocolate Ensure®. Rats maintained on an ad libitum diet of rat chow and water were given 3‐h access to Ensure® daily for two weeks. One day following the end of this period, preproenkephalin gene expression was measured with quantitative in situ hybridization. Compared with control animals, rats that had been exposed to Ensure® had significantly reduced enkephalin gene expression in several striatal regions including the ventral striatum (nucleus accumbens), a finding that was confirmed in a different group with Northern blot analysis. Rats fed this regimen of Ensure® did not differ in weight from controls. In contrast to chronic Ensure®, acute ingestion of Ensure® did not appear to affect enkephalin peptide gene expression. These results suggest that repeated consumption of a highly rewarding, energy‐dense food induces neuroadaptations in cognitive‐motivational circuits.
Developmental elimination of ectopic projection sites for the transgenic OR gene that has lost zone specificity in the olfactory epithelium
Authors: Nakatani Hiroko , Serizawa Shou , Nakajima Miho , Imai Takeshi , Sakano Hitoshi
Published: November 2003

In rodents, olfactory receptor (OR) genes are expressed in one of four zones in the olfactory epithelium (OE), and olfactory sensory neurons (OSNs) expressing the same OR project their axons to a specific set of glomeruli on the olfactory bulb (OB). Using the yeast artificial chromosome (YAC) transgenic system, we have analysed the expression of the murine OR gene MOR29A of the MOR28 cluster located on chromosome 14. Although expression of the endogenous MOR29A was restricted to the most dorsomedial zone, the transgenic MOR29A (Tg MOR29A) was expressed in all four zones of the OE. When the OB of the transgenic mouse was analysed, the axons of the OSNs expressing Tg MOR29A were found to project not only to the dorsal side but also to the ventral side of the OB as well. The ectopic projection sites on the ventral side gradually disappear during postnatal development. Naris occlusion prevents this elimination, suggesting that odorant stimulation is involved in eliminating the ectopic projection sites.
Retrosplenial cortex (BA 29/30) hypometabolism in mild cognitive impairment (prodromal Alzheimer's disease)
Authors: Nestor P. J. , Fryer T. D. , Ikeda M. , Hodges J. R.
Published: November 2003

Previous group studies using positron emission tomography to assess resting cerebral glucose metabolism in very early Alzheimer's disease and mild cognitive impairment have identified the posterior cingulate and adjacent cingulo‐parietal cortex as the first isocortical area to develop hypometabolism. We studied the profile of resting cerebral glucose metabolism in individuals with mild cognitive impairment to assess whether more specific and stereotyped regional hypometabolism would be evident across subjects. The study found that the most consistently hypometabolic region between individual subjects was a subregion of the posterior cingulate, the retrosplenial cortex (BA 29/30). This result is discussed in the context of regional connectivity, focal lesion evidence and functional activation studies of episodic memory paradigms in both normal and Alzheimer's disease groups. We propose that the retrosplenial cortex may represent a key junction between prefrontal areas involved in implementing retrieval strategies for episodic memory and hippocampal‐based mnemonic processing; we therefore interpret the retrosplenial hypometabolism as a probable contributor to the memory impairment seen in mild cognitive impairment by disconnecting these two anatomical networks.
The role of nitric oxide in morphine dependence and withdrawal excitation of rat oxytocin neurons
Authors: Bull Philip M. , Ludwig Mike , Blackburn‐Munro Gordon J. , Delgado‐Cohen Helena , Brown Colin H. , Russell John A.
Published: November 2003

Magnocellular oxytocin neurons develop morphine dependence after intracerebroventricular infusion for 5 days as revealed by their profound excitation following naloxone‐induced withdrawal. Oxytocin neurons strongly express nitric oxide synthase (NOS) and nitric oxide (NO) inhibits their activity. This study investigated whether excitation of oxytocin neurons during morphine withdrawal involves reduced activity of NOS and NO. Neuron activity was measured in urethane‐anaesthetized rats with blood sampling for oxytocin radioimmunoassay and extracellular single unit firing rate recording of supraoptic nucleus oxytocin neurons. To compare morphine‐dependent and ‐naive rats oxytocin secretion was measured during stimulation by intravenous hypertonic saline infusion. Prior treatment with Nω‐nitro‐l‐arginine methyl ester, a NOS inhibitor, facilitated osmotically stimulated oxytocin secretion in both morphine‐dependent and ‐naive rats. The facilitation was not different between these groups when corrected for the slower responses observed in morphine‐dependent rats. Treatment of morphine‐dependent rats with Nω‐nitro‐l‐arginine methyl ester also enhanced oxytocin secretion during naloxone‐precipitated withdrawal. Oxytocin neurons excited by withdrawal were recorded during microdialysis application to the supraoptic nucleus of the NO donor sodium nitroprusside alone and in combination with the GABAA antagonist bicuculline. Sodium nitroprusside inhibited oxytocin neurons during naloxone‐precipitated morphine withdrawal and, while bicuculline alone increased firing rate, it did not reduce the inhibition by sodium nitroprusside, in contrast with previous findings in naive rats. Together, these findings indicate that NO restraint of oxytocin secretion is not curtailed during morphine dependence and remains a potent inhibitor of withdrawal excitation despite reduced effectiveness on GABA innervation of the supraoptic nucleus. Hence there is no evidence that changes in NO regulation underlie excitation of oxytocin neurons during opiate withdrawal in morphine dependence.
Neural architecture of choice behaviour in a concurrent interval schedule
Authors: Kalenscher Tobias , Diekamp Bettina , Güntürkün Onur
Published: November 2003

Concurrent interval schedules are classic experimental paradigms that are traditionally employed in psychological research on choice behaviour. To analyse the neural basis of choice in a concurrent fixed interval schedule, pigeons were trained to peck on two response keys. Responses were differentially rewarded in key specific short or long time intervals (SI vs. LI). Using tetrodotoxin, we reversibly blocked the neostriatum caudolaterale (NCL, the avian functional equivalent of the prefrontal cortex), avian caudate‐putamen and nucleus accumbens to examine their contribution. A detailed analysis of baseline choice behaviour revealed that response distribution and key affinity were determined by cued or time‐related expectancy for rewards on the SI key. The pigeons' response frequency increased on the SI key and decreased on the LI key with increasing temporal proximity to the SI reward and pigeons switched to the LI key after reward delivery. Pecking bursts on the LI key were negatively correlated with bursts on the SI key. Neostriatum caudolaterale inactivation did not affect pecking activity per se but interfered with reward‐related temporal modulation of pecking frequency, switching pattern and coupling of LI to SI pecks. Blockade of caudate‐putamen resulted in a complete behavioural halt, while inactivation of nucleus accumbens diminished operant behaviour without affecting consummatory responses. These data suggest that the NCL is tuned via indirect striato‐pallial projections to integrate cued or time‐related reward expectancy into a response selection process in order to set, maintain or shift goals. The NCL possibly feeds forward the resulting motor commands to the caudate‐putamen for execution.
The New Zealand Dietetic Association
Authors: Wynne Amanda
Published: November 2003

Summary  The New Zealand Dietetic Association (NZDA) was founded in 1943 and is one the most well‐established professional organisations in New Zealand. The Association currently represents around 500 individual dietitians and associated professionals practising in diverse areas of dietetics throughout the country. Corporate membership is also available; at present there are around 15 corporate members of the Association. The NZDA aims to ensure that members are recognised as the most credible source of food and nutrition knowledge within New Zealand, and also aims to contribute to better food and nutrition for all New Zealanders. The key goals of the Association are to sustain a strong and active membership by continuing to develop benefits offered to members, to enhance the profile of the dietetic profession, and to provide professional support to members to help strengthen their professional performance. The activities of the Association are diverse and include promotion of good nutrition through the media, active involvement in making submissions, e.g. on government policy on nutrition, organisation of a national annual conference, production of numerous publications, provision of information via its website, and the development of partnerships with key stakeholders and industry colleagues to promote good nutrition amongst the population of New Zealand.
Development of an efficient cis‐trans‐cis ribozyme cassette to inactivate plant genes
Authors: Bussière Frédéric , Ledû Sylvain , Girard Marianne , Héroux Maryse , Perreault Jean‐Pierre , Matton Daniel P.
Published: November 2003

Inactivation of a targeted gene is one of the main strategies used to understand their precise cellular role. In plants, apart from chemical or physical mutagenesis and random insertions of DNA elements followed by screening for a desired phenotype, the most common strategy to inhibit the expression of a given gene involves RNA silencing. This can be achieved either through antisense suppression, sense over‐expression leading to co‐suppression, or expression of double‐stranded DNA constructs (dsRNA). The use of ribozymes to inhibit gene product accumulation has only been occasionally attempted, mainly because of the more complex genetic engineering procedure involved, although the specificity of ribozymes can be an important factor when targeting close members of a gene family. We report here the development of a new cis‐acting ribozyme cassette for the production of RNAs with desired termini. Attention to many details has been brought in order to provide a powerful procedure for plant application. For example, ultrastable GNRA tetraloops were substituted for both loops II and III of cis‐acting hammerhead sequences, thereby favouring folding into the catalytically active structure that results in the self‐cleavage of all transcripts. We demonstrate the usefulness of this cassette by producing a ribozyme that cleaves in trans, originally embedded in the cis‐acting self‐cleaving cassette. The activity of the cis‐trans‐cis construct, was demonstrated both in vitro and in vivo, in transgenic plants with the specific cleavage of an mRNA encoding a 2‐oxo‐glutarate‐dependant dioxygenase predominantly expressed in pistils tissues and in leaves, from the wild potato Solanum chacoense.
Culture and Entrepreneurship – Remarks on Transculturality as Practice
Authors: Pütz Robert
Published: November 2003

The most recent media debate about a new ‘Turkish entrepreneurship’ in Germany triggered off the fundamental reflections on the necessarily critical conceptualisation of the relation between ‘culture’ and entrepreneurial action. The dominating concepts in the field of ‘ethnic business’, in which questions of cultural orientation in entrepreneurial action have been a central issue for some time, can serve as a starting point for this analysis. For understanding the term culture and the conceptualisation of culture in conjunction with entrepreneurial action, a few critical remarks and a shift in perspective are necessary. Contributions of economic geography inspired by the ‘cultural turn’, which shows alternative ways of thinking about the connection between culture and economy by using a new understanding of culture may be utilised here. Focusing on the group of ‘German‐Turkish entrepreneurs’ and bearing in mind the idea of ‘transculturality in practice’ this paper will conclude with an outline of a number of conceptual considerations for action‐oriented research on the relation between culture and entrepreneurial action.