bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of protein lysate microarrays to molecular marker verification and quantification
Authors: Ramaswamy Anitha , Lin E , Chen Iou , Mitra Rahul , Morrisett Joel , Coombes Kevin , Ju Zhenlin , Kapoor Mini
Published: November 2005

This study presents the development and application of protein lysate microarray (LMA) technology for verification of presence and quantification of human tissue samples for protein biomarkers. Sub-picogram range sensitivity has been achieved on LMA using a non-enzymatic protein detection methodology. Results from a set of quality control experiments are presented and demonstrate the high sensitivity and reproducibility of the LMA methodology. The optimized LMA methodology has been applied for verification of the presence and quantification of disease markers for atherosclerosis. LMA were used to measure lipoprotein [a] and apolipoprotein B100 in 52 carotid endarterectomy samples. The data generated by LMA were validated by ELISA using the same protein lysates. The correlations of protein amounts estimated by LMA and ELISA were highly significant, with r2≥ 0.98 (p ≤ 0.001) for lipoprotein [a] and with r2≥ 0.94 (p ≤ 0.001) for apolipoprotein B100. This is the first report to compare data generated using proteins microarrays with ELISA, a standard technology for the verification of the presence of protein biomarkers. The sensitivity, reproducibility, and high-throughput quality of LMA technology make it a potentially powerful technology for profiling disease specific protein markers in clinical samples.
Prevalence and correlates of abscesses among a cohort of injection drug users
Authors: Lloyd-Smith Elisa , Kerr Thomas , Hogg Robert S , Li Kathy , Montaner Julio SG , Wood Evan
Published: November 2005

Recent studies have indicated that injection-related infections such as abscesses and cellulitis account for the majority of emergency room visits and acute hospitalizations accrued by local injection drug users. The objective of this analysis was to examine the prevalence and correlates of developing an abscess among a cohort of injection drug users in Vancouver and to identify socio-demographic and drug use variables associated with abscesses at baseline. We examined abscesses among participants enrolled in a prospective cohort of injection drug users. Categorical variables were analyzed using the Pearson's chi-square test and continuous variables were analyzed using the Wilcoxon signed rank test. Among 1 585 baseline participants, 341 (21.5%) reported having an abscess in the last six months. In a logistic regression model that adjusted for all variables that were associated with having an abscess at p < 0.1 in univariate analyses, female gender [odds ratio (OR) = 1.7, [95%CI: 1.2 – 2.4]; p = 0.002), recent incarceration (OR = 1.7, [95%CI: 1.3 – 2.2]; p < 0.001), sex trade involvement (OR = 1.4 [95% CI: 1.0 – 2.0]; p = 0.03), frequent cocaine use (OR = 1.5 [95%CI: 1.2 – 2.0]; p = 0.002) and HIV serostatus (OR = 1.5, [95%CI: 1.2 – 2.0]; p = 0.003) were positively associated with having an abscess. Explanations for these associations require further study, and interventions are needed to address this highly prevalent concern.
Retroperitoneal myolipoma
Authors: Behranwala Kasim A , Chettiar Krissen , El-Bahrawy Mona , Stamp Gordon , Kakkar Ajay K
Published: November 2005

Background

Myolipoma is a benign tumour in which smooth muscle cells are mixed with adipocytes.

Case presentation

A 34-year old lady presented with a mass in the right iliac fossa detected on computerised tomographic (CT) scan. Wide excision of the retroperitoneal mass was done. Histopathology showed features of myolipoma. There was no recurrence or metastasis at three years.

Conclusion

Myolipoma is a rare benign entity; hence a benign course and good prognosis are expected.
Zebrafish sex determination and differentiation: Involvement of FTZ-F1 genes
Authors: von Hofsten Jonas , Olsson Per-Erik
Published: November 2005

Sex determination is the process deciding the sex of a developing embryo. This is usually determined genetically; however it is a delicate process, which in many cases can be influenced by environmental factors. The mechanisms controlling zebrafish sex determination and differentiation are not known. To date no sex linked genes have been identified in zebrafish and no sex chromosomes have been identified. However, a number of genes, as presented here, have been linked to the process of sex determination or differentiation in zebrafish. The zebrafish FTZ-F1 genes are of central interest as they are involved in regulating interrenal development and thereby steroid biosynthesis, as well as that they show expression patterns congruent with reproductive tissue differentiation and function. Zebrafish can be sex reversed by exposure to estrogens, suggesting that the estrogen levels are crucial during sex differentiation. The Cyp19 gene product aromatase converts testosterone into 17 beta-estradiol, and when inhibited leads to male to female sex reversal. FTZ-F1 genes are strongly linked to steroid biosynthesis and the regulatory region of Cyp19 contains binding sites for FTZ-F1 genes, further linking FTZ-F1 to this process. The role of FTZ-F1 and other candidates for zebrafish sex determination and differentiation is in focus of this review.
Trading people versus trading time: What is the difference?
Authors: Damschroder Laura J , Roberts Todd R , Goldstein Christine C , Miklosovic Molly E , Ubel Peter A
Published: November 2005

Background

Person trade-off (PTO) elicitations yield different values than standard utility measures, such as time trade-off (TTO) elicitations. Some people believe this difference arises because the PTO captures the importance of distributive principles other than maximizing treatment benefits. We conducted a qualitative study to determine whether people mention considerations related to distributive principles other than QALY-maximization more often in PTO elicitations than in TTO elicitations and whether this could account for the empirical differences.

Methods

64 members of the general public were randomized to one of three different face-to-face interviews, thinking aloud as they responded to TTO and PTO elicitations. Participants responded to a TTO followed by a PTO elicitation within contexts that compared either: 1) two life-saving treatments; 2) two cure treatments; or 3) a life-saving treatment versus a cure treatment.

Results

When people were asked to choose between life-saving treatments, non-maximizing principles were more common with the PTO than the TTO task. Only 5% of participants considered non-maximizing principles as they responded to the TTO elicitation compared to 68% of participants who did so when responding to the PTO elicitation. Non-maximizing principles that emerged included importance of equality of life and a desire to avoid discrimination. However, these principles were less common in the other two contexts. Regardless of context, though, participants were significantly more likely to respond from a societal perspective with the PTO compared to the TTO elicitation.

Conclusion

When lives are at stake, within the context of a PTO elicitation, people are more likely to consider non-maximizing principles, including the importance of equal access to a life-saving treatment, avoiding prejudice or discrimination, and in rare cases giving treatment priority based purely on the position of being worse-off.
CD8+, HLA-unrestricted, cytotoxic T-lymphocyte line against malignant melanoma
Authors: Somasundaram Rajasekharan , Caputo Laura , Guerry DuPont , Herlyn Dorothee
Published: November 2005

A CD8+cytotoxic T lymphocyte (CTL) line was derived from the peripheral blood mononuclear cells of a patient with primary melanoma. The CD8+CTL line specifically lysed the autologous primary melanoma cells and not the natural killer cell-sensitive K562 cells or lymphokine activated killer cell-sensitive DAUDI cells. When a large panel of human leukocyte antigen (HLA)-matched and -unmatched allogeneic melanoma, glioma, breast and colorectal carcinoma cells was tested as targets in cytolysis assays, 4 HLA-matched and two HLA-unmatched allogeneic metastatic melanoma lines were lysed by the CD8+CTL. Lysis of autologous and allogeneic melanoma cells was dependent on the effector-to-target cell ratio. Lysis of autologous melanoma cells was not blocked by anti-HLA class I or class II antibodies, confirming that the cytolytic activity of the CD8+CTL was HLA-unrestricted. CTL lysis of autologous melanoma cells was CD3 (T cell receptor) dependent and FAS-FAS-L, and CD1 independent. Identification of the melanoma-associated antigen recognized by the HLA-unrestricted CTL may provide a vaccine for a broad population of melanoma patients.
Autoantibody profiles in the sera of patients with Q fever: characterization of antigens by immunofluorescence, immunoblot and sequence analysis
Authors: Camacho MT , Outschoorn I , Tellez A , Sequí J
Published: November 2005

Recent reports have shown that some of the immunological aspects of Q fever, a rickettsiosis caused byCoxiella burnetii, could be related to self-antigen responses. The aim of this study was to determine the specificity of the autoantibody response of patients with acute and chronic Coxiella infections. Smooth muscle and cardiac muscle-specific autoantibodies were observed in significant percentages in acutely or chronically affected Q fever patients when compared to healthy volunteers. Moreover, the incidence of cardiac muscle-specific autoantibody was significantly higher among chronically ill patients compared to acutely ill patients. Moreover, a band of 50 kD of a HeLa extract was detected in most of the sera of individuals with chronic infections and previous sequence analysis suggests that this antigen presents a high degree of homology with the human actin elongation factor 1 alpha. Further research would be necessary to confirm if antibodies to human cytoskeletal proteins could be of clinical importance in chronically infected Q fever patients.
Co-occurrence of autoimmune thyroid disease in a multiple sclerosis cohort
Authors: Sloka JS , Phillips Pryse-WEM , Stefanelli M , Joyce C
Published: November 2005

Background

Multiple sclerosis (MS), Hashimoto's disease and Graves' disease are autoimmune diseases that may share similar pathogenic mechanisms. The co-occurrence rates and demographic characteristics of Graves' disease and Hashimoto's disease (HT) in our MS population are compared with the general population.

Methods

The prevalence of thyroid disease in our MS patients was determined by chart review and survey. Previous diagnosis of thyroid disease, age at diagnosis, treatment used, and about the use of disease modifying medications used to treat their MS were asked. Chart reviews were used to estimate the population prevalence of Graves' disease and Hashimoto's disease and to estimate the demographics of patients with thyroid disease.

Results

A significant co-occurrence of Graves' disease with MS (p = 0.002), and a non-significant co-occurrence of Hashimoto's disease were noted (p = 0.097). No difference in the age of onset or gender of thyroid disease in MS patients compared to the general population was found.

Conclusion

There is a significant co-occurrence in patients with MS and Graves' disease, and a trend to co-occurrence in patients with MS and Hashimoto's disease. There are no differences in the demographics of patients with thyroid disease in our MS patients compared to the general population.
Paucity of chimeric gene-transposable element transcripts in the Drosophila melanogaster genome
Authors: Lipatov Mikhail , Lenkov Kapa , Petrov Dmitri A , Bergman Casey M
Published: November 2005

Background

Recent analysis of the human and mouse genomes has shown that a substantial proportion of protein coding genes andcis-regulatory elements contain transposable element (TE) sequences, implicating TE domestication as a mechanism for the origin of genetic novelty. To understand the general role of TE domestication in eukaryotic genome evolution, it is important to assess the acquisition of functional TE sequences by host genomes in a variety of different species, and to understand in greater depth the population dynamics of these mutational events.

Results

Using anin silicoscreen for host genes that contain TE sequences, we identified a set of 63 mature "chimeric" transcripts supported by expressed sequence tag (EST) evidence in theDrosophila melanogastergenome. We found a paucity of chimeric TEs relative to expectations derived from non-chimeric TEs, indicating that the majority (~80%) of TEs that generate chimeric transcripts are deleterious and are not observed in the genome sequence. Using a pooled-PCR strategy to assay the presence of gene-TE chimeras in wild strains, we found that over half of the observed chimeric TE insertions are restricted to the sequenced strain, and ~15% are found at high frequencies in North AmericanD. melanogasterpopulations. Estimated population frequencies of chimeric TEs did not differ significantly from non-chimeric TEs, suggesting that the distribution of fitness effects for the observed subset of chimeric TEs is indistinguishable from the general set of TEs in the genome sequence.

Conclusion

In contrast to mammalian genomes, we found that fewer than 1% ofDrosophilagenes produce mRNAs that includebona fideTE sequences. This observation can be explained by the results of our population genomic analysis, which indicates that most potential chimeric TEs inD. melanogasterare deleterious but that a small proportion may contribute to the evolution of novel gene sequences such as nested or intercalated gene structures. Our results highlight the need to establish the fixity of putative cases of TE domestication identified using genome sequences in order to demonstrate their functional importance, and reveal that the contribution of TE domestication to genome evolution may vary drastically among animal taxa.
Dynamic regulation of integrin activation by intracellular and extracellular signals controls oligodendrocyte morphology
Authors: Olsen Inger Marie , ffrench-Constant Charles
Published: November 2005

Background

Myelination requires precise control of oligodendrocyte morphology and myelin generation at each of the axons contacted by an individual cell. This control must involve the integration of extracellular cues, such as those on the axon surface, with intrinsic developmental programmes. We asked whether integrins represent one class of oligodendrocyte cell-surface receptors able to provide this integration.

Results

Integrins signal via a process of activation, a conformational change that can be induced either by "outside-in" signals comprising physiological extracellular matrix ligands (mimicked by the pharmacological use of the divalent cation manganese) or "inside-out" signalling molecules such as R-Ras. Increasing levels of outside-in signalling via the laminin receptor α6β1 integrin were found to promote oligodendrocyte processing and myelin sheet formation in culture. Similar results were obtained when inside-out signalling was increased by the expression of a constitutively-active R-Ras. Inhibiting inside-out signalling by using dominant-negative R-Ras reduces processes and myelin sheets; importantly, this can be partially rescued by the co-stimulation of outside-in signalling using manganese.

Conclusion

The balance of the equilibrium between active and inactive integrins regulates oligodendrocyte morphology, which is itself regulated by extrinsic and intrinsic cues so providing a mechanism of signal integration. As laminins capable of providing outside-in signals are present on axons at the time of myelination, a mechanism exists by which morphology and myelin generation might be regulated independently in each oligodendrocyte process.
Analysis of variation of amplitudes in cell cycle gene expression
Authors: Liu Delong , Gaido Kevin W , Wolfinger Russ
Published: November 2005

Background

Variation in gene expression among cells in a population is often considered as noise produced from gene transcription and post-transcription processes and experimental artifacts. Most studies on noise in gene expression have emphasized a few well-characterized genes and proteins. We investigated whether different cell-arresting methods have impacts on the maximum expression levels (amplitudes) of a cell cycle related gene.

Results

By introducing random noise, modeled by a von Mises distribution, to the phase angle in a sinusoidal model in a cell population, we derived a relationship between amplitude and the distribution of noise in maximum transcription time (phase). We applied our analysis to Whitfield's HeLa cell cycle data. Our analysis suggests that among 47 cell cycle related genes common to the 2nd experiment (thymidine-thymidine method) and the 4th experiment (thymidine-nocodazole method): (i) the amplitudes of CDC6 and PCNA, which are expressed during G1/S phase, are smaller in the 2nd experiment than in the 4th, while the amplitude of CDC20, which is expressed during G2/M phase, is smaller in the 4th experiment; and (ii) the two cell-arresting methods had little impact on the amplitudes of the other 43 genes in the 2nd and 4th experiments.

Conclusion

Our analysis suggests that procedures that arrest cells in different stages of the cell cycle differentially affect expression of some cell cycle related genes once the cells are released from arrest. The impact of the cell-arresting method on expression of a cell cycle related gene can be quantitatively estimated from the ratio of two estimated amplitudes in two experiments. The ratio can be used to gauge the variation in the phase/peak expression time distribution involved in stochastic transcription and post-transcriptional processes for the gene. Further investigations are needed using normal, unperturbed and synchronized HeLa cells as a reference to compare how many cell cycle related genes are directly and indirectly affected by various cell-arresting methods.
Development of an improved microneutralization assay for respiratory syncytial virus by automated plaque counting using imaging analysis
Authors: Zielinska Edyta , Liu Daiqing , Wu Hong-Yin , Quiroz Jorge , Rappaport Ruth , Yang Da-Ping
Published: November 2005

Background

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in infants and young children. Although several experimental RSV vaccines are under investigation, immuno therapy is the only treatment currently available. In assessing the immunogenicity of various vaccine formulations, a plaque reduction neutralization assay for the evaluation of RSV neutralizing antibody has been widely used. The method produces reliable results, but it is tedious and labor intensive as it relies on manual counting by laboratory personnel. To facilitate evaluation of phase II and phase III vaccine clinical trials, a more rapid, reliable and efficient neutralization assay is needed.

Results

An improved microneutralization assay for quantifying RSV neutralizing antibodies was developed using an ImmunoSpot® Series I Analyzer (Cellular Technology Ltd., Cleveland, OH) for automated plaque counting. The method is an improvement of the established classical microneutralization assay in which immunostained plaques on transparent tissue culture plates are counted manually under a dissecting microscope. Image analyzer technology allows for fully automated counting of plaques distributed throughout an entire well. Adjustments, such as the use of opaque tissue culture plates and the TMB substrate, True Blue™ (KPL, Gaithersburg, MD), were required to adapt the assay for optimal detection of plaques by the image analyzer. The suitability and the accuracy of the method for counting RSV plaques were determined by comparative testing of a reference serum and two control sera by manual and automated counting methods. The results showed that the two methods were highly correlated (R = 0.9580) and the titers generated by them were within two-fold.

Conclusion

Our results demonstrate that the semi-automated assay is rapid and reliable. It provides results within two fold to the classical plaque microneutralization assay and is readily applied to the evaluation of neutralizing antibody titers in sera obtained from epidemiology or vaccine clinical trials.
Using genomic DNA-based probe-selection to improve the sensitivity of high-density oligonucleotide arrays when applied to heterologous species
Authors: Hammond John P , Broadley Martin R , Craigon David J , Higgins Janet , Emmerson Zoe F , Townsend Henrik J , White Philip J , May Sean T
Published: November 2005

High-density oligonucleotide (oligo) arrays are a powerful tool for transcript profiling. Arrays based on GeneChip® technology are amongst the most widely used, although GeneChip® arrays are currently available for only a small number of plant and animal species. Thus, we have developed a method to improve the sensitivity of high-density oligonucleotide arrays when applied to heterologous species and tested the method by analysing the transcriptome of Brassica oleracea L., a species for which no GeneChip® array is available, using a GeneChip® array designed for Arabidopsis thaliana (L.) Heynh. Genomic DNA from B. oleracea was labelled and hybridised to the ATH1-121501 GeneChip® array. Arabidopsis thaliana probe-pairs that hybridised to the B. oleracea genomic DNA on the basis of the perfect-match (PM) probe signal were then selected for subsequent B. oleracea transcriptome analysis using a .cel file parser script to generate probe mask files. The transcriptional response of B. oleracea to a mineral nutrient (phosphorus; P) stress was quantified using probe mask files generated for a wide range of gDNA hybridisation intensity thresholds. An example probe mask file generated with a gDNA hybridisation intensity threshold of 400 removed > 68 % of the available PM probes from the analysis but retained >96 % of available A. thaliana probe-sets. Ninety-nine of these genes were then identified as significantly regulated under P stress in B. oleracea, including the homologues of P stress responsive genes in A. thaliana. Increasing the gDNA hybridisation intensity thresholds up to 500 for probe-selection increased the sensitivity of the GeneChip® array to detect regulation of gene expression in B. oleracea under P stress by up to 13-fold. Our open-source software to create probe mask files is freely available http://affymetrix.arabidopsis.info/xspecies/ and may be used to facilitate transcriptomic analyses of a wide range of plant and animal species in the absence of custom arrays.
Equine herpesvirus 2 (EHV-2) infection in thoroughbred horses in Argentina
Authors: Craig María I , Barrandeguy María E , Fernández Fernando M
Published: November 2005

Background

Equine herpesvirus 2 is a gamma-herpesvirus that infects horses worldwide. Although EHV-2 has been implicated in immunosuppression in foals, upper respiratory tract disease, conjunctivitis, general malaise and poor performance, its precise role as a pathogen remains uncertain. The purpose of the present study was to analyse the incidence of EHV-2 in an Argentinean horse population and correlate it with age and clinical status of the animals.

Results

A serological study on 153 thoroughbred racing horses confirmed the presence of EHV-2 in the Argentinean equine population. A virus neutralization test showed a total of 79.7 % animals were sero-positive for EHV-2. An increase in antibodies titre with age as well as infection at earlier ages were observed.

EHV-2 was isolated from 2 out of 22 nasal swabs from horses showing respiratory symptoms. The virus grew slowly and showed characteristic cytopathic effect after several blind passages on RK13 cells. The identity of the isolates was confirmed by nested PCR and restriction enzyme assay (REA).

Conclusion

This is the first report on the presence of EHV-2 in Argentina and adds new data to the virus distribution map. Though EHV-2 was isolated from foals showing respiratory symptoms, further studies are needed to unequivocally associate this virus with clinical symptoms.
CD16+ monocytes in human cutaneous leishmaniasis: increased ex vivo levels and correlation with clinical data
Authors: Soares George , Barral Aldina , Costa Jackson M , Barral-Netto Manoel , Van Weyenbergh Johan
Published: November 2005

Peripheral blood CD16 (Fc receptor for immunoglobulin G III)-positive monocytes have been shown to expand in different pathological conditions, such as cancer, asthma, sepsis, human immunodeficiency virus infection, and AIDS progression, but data in leishmaniasis are lacking. We found that cutaneous leishmaniasis patients (n=15) displayed a significant increase in the ercentage (3.5 vs. 10.1) as well as mean fluorescent intensity (13.5 vs. 29.2) of ex vivo CD16 expression in monocytes as compared with healthy controls. We observed a significant positive correlation between the percentage of ex vivo CD16+ monocytes and lesion size (P=0.0052, r=0.75) or active transforming growth factor-β plasma levels (P=0.0017, r=0.78). In addition, two patients with nonhealing lesions during a 3-year follow-up had high (9.1–19.4%) CD16 levels at diagnosis. Our data suggest a deleterious role for CD16 in human leishmaniasis, as well as its possible use as a marker for disease severity and/or adverse disease outcome.
HIV-1 TAT represses transcription of the bone morphogenic protein receptor-2 in U937 monocytic cells
Authors: Caldwell Robert L , Gadipatti Radhika , Lane Kirk B , Shepherd Virginia L
Published: November 2005

The bone morphogenetic protein receptor-2 (BMPR2) is a member of the transforming growth factor-β receptor family and is expressed on the surface of several cell type including endothelial cells and macrophages. Recently, a cause for familial primary pulmonary hypertension (FPPH) has been identified as mutations in the gene encoding BMPR2. Three forms of pulmonary hypertension (PH) exist, including PPH, FPPH, and PH secondary to other etiologies (sporadic PH) such as drug abuse and human immunodeficiency virus (HIV) infection. It is interesting that these subtypes are histologically indistinguishable. The macrophage is a key target cell for HIV-1, significantly altering macrophage cell function upon infection. HIV-1 trans-activator of transcription (Tat), an immediate-early product of the HIV-1 lifecycle, plays an important role in mediating HIV-induced modulation of host cell function. Our laboratory has previously shown that Tat represses mannose receptor transcription in macrophages. In the current study, we examined activity from the BMPR2 promoter in the macrophage cell line U937 and potential regulation by Tat. Transfection of U937 cells with BMPR2 promoter-reporter constructs revealed dose-dependent repression of BMPR2 promoter activity in the presence of Tat. Experiments using truncations of the BMPR2 promoter localized Tat-mediated repression to the first 208 bases of the promoter. Decreased BMPR2 transcription resulted in altered downstream signaling. Similar to mothers against decapentaplegics (SMAD) phosphorylation and SMAD6 expression, in response to BMP2 treatment, were down-regulated after Tat treatment. Finally, HIV-1 infection and treatment with Tat protein of the U937 human monocytic cell line resulted in a decreased, endogenous BMPR2 transcript copy number.
Mast cells, which interact with Escherichia coli, up-regulate genes associated with innate immunity and become less responsive to FcεRI-mediated activation
Authors: Kulka Marianna , Fukuishi Nobuyuki , Rottem Menachem , Mekori Yoseph A , Metcalfe Dean D
Published: November 2005

Mast cells, which are associated with T helper cell type 2-dependent inflammation, have now been implicated in the innate immune response. To further characterize how mast cells are programmed to respond to infectious organisms, we used expression profiling using DNA microarray analysis of gene expression by human mast cells (huMC) during ingestion of Escherichia coli and examined immunoglobulin E (IgE)-mediated degranulation. Analysis of data revealed that specific groups of genes were modulated, including genes encoding transcription factors, cell signaling molecules, cell cycle regulators, enzymes, cytokines, novel chemokines of the CC family, adhesion molecules, and costimulatory molecules. Enzyme-linked immunosorbent assay analysis confirmed the production of tumor necrosis factor and the chemokines CC chemokine ligand (CCL)-1/I-309, CCL-19/macrophage-inflammatory protein-3β (MIP-3β), and CCL-18/MIP-4; flow cytometry confirmed the up-regulation of carcinoembryonic antigen-related cell adhesion molecule 1, the integrin CD49d, and CD80. Coincubation with E. coli down-regulated Fc receptor for IgE I (FcεRI) expression and FcεRI-mediated huMC degranulation. These data are consistent with the concept that bacterial exposure directs mast cell responses toward innate immunity and away from IgE-mediated effects.
Comparison of conventional extracorporeal circulation and minimal extracorporeal circulation with respect to microbubbles and microembolic signals
Authors: Perthel M , Kseibi S , Sagebiel F , Alken A , Laas J
Published: November 2005

The intention of minimal extracorporeal circulation (MECC) is to reduce priming volume and minimize contact of blood with polymers and air in a closed system. In contrast to conventional extracorporeal circulation (ECC), a venous reservoir is missing. Thus, air trapping is limited and avoidance of bubble embolism is a major concern. This study investigates microbubbles (MBB) number and size in the venous and arterial lines of ECC and MECC compared to the number of microembolic signals (MES) in the right and left middle cerebral artery (MCA).

Twenty patients undergoing coronary surgery were operated either with conventional ECC (cardiotomy reservoir, Rotaflow pump, Quadrox oxygenator, Quart filter) or MECC (Quart filter, Rotaflow pump, Quadrox oxygenator). Number and size of MBB were monitored in the venous and arterial lines with an ultrasound Doppler system. MES in right and left MCAs were measured by transcranial Doppler (TCD) monitoring. Patients undergoing MECC had additional sealing of the venous cannula by a ligature at the site of its insertion into the right atrium.

There were no significant differences between groups with respect to age, X-clamping, bypass time and number of distal anastomoses. The number of MES and MBB in the arterial line was comparable between the groups. On the venous side, MECC-perfusion shows a significantly lower number of MBB. This could be explained with the additional sealing of the venous cannula. Furthermore, our data indicate that the MBB-volume reaching the pump will also appear in the arterial outflow and into the patient’s MCA. For this reason, the avoidance of air contamination is a major concern for surgeons, anaesthesiologists and perfusionists.
Acute renal failure following open heart surgery: risk factors and prognosis
Authors: Bahar Ilknur , Akgul Ahmet , Ozatik Mehmet Ali , Vural Kerem M , Demirbag Ali E , Boran Mediha , Tasdemir Oguz
Published: November 2005

Background: Acute renal failure (ARF) development after cardiac surgery carries high mortality and morbidity.

Methods: Out of 14 437 consecutive patients undergoing open-heart surgery between January 1991 and May 2001, 168 (1.16%) developed postoperative ARF mandating hemodialysis. Possible perioperative risk factors, and the prognosis of this dreadful, often fatal complication were investigated.

Results: The mortality rate in this group was 79.7% (134 patients). The risk factors associated with postoperative ARF were advanced age (p-0.000), diabetes mellitus (p-0.000), hypertension (p-0.000), high preoperative serum creatinine levels (p-0.004), impaired left ventricular function (p-0.002), urgent operation (p-0.000) or reoperation (p-0.007), prolonged cardiopulmonary bypass (CPB) (p-0.000) and aortic cross-clamp (ACC) (p-0.000) periods, level of hypothermia (p-0.000), concomitant procedures (p-0.000), low cardiac output state (p-0.000), re-exploration for bleeding or pericardial tamponade (p-0.000), and deep sternal or systemic infection (p-0.000). Of those who could be discharged from hospital, renal functions were restored in 21 patients (12.5%); however, eight patients (4.7%) became hemodialysis dependent. The mean follow-up period was 5.79/3.2 years (range: 4 months to 13 years; a total of 195 patient-years), and 10-year survival was 58.69/10.2% in the discharged patients.

Conclusions: ARF development after cardiac surgery often results in high morbidity and mortality. Recognizing risk factors permits the timely institution of proper treatment, which is the key to reducing untoward outcomes.
A new practical technique to reduce allogeneic blood exposure and hospital costs while preserving clotting factors after cardiopulmonary bypass: the Hemobag®
Authors: Samolyk Keith A , Beckmann Scott R , Bissinger Randall C
Published: November 2005

Recent data independently linking allogeneic blood use to increased morbidity and mortality after cardiopulmonary bypass (CPB) warrants the study of new methods to employ unique and familiar technology to reduce allogeneic blood exposure. The Hemobag® allows the open-heart team to concentrate residual CPB circuit contents and return a high volume of autologous clotting factors and blood cells to the patient.

Fifty patients from all candidates were arbitrarily selected to receive the Hemobag® (HB) therapy. A retrospective control group of 50 non-Hemobag® (NHB) patients were matched to the HB group patient-by-patient for comparison according to surgeon, type of procedure, age, body surface area (BSA), body weight and CPB time. Many efforts to conserve blood (Cell Saver® and ANH) were employed in both groups. Post-CPB cell washing of circuit contents was additionally employed in the control group.

There were no significant differences between the HB and NHB groups in regard to patient morphology, pre-op cell concentrations, distribution of surgeon or procedures (41% valve, 16% valve/coronary artery bypass graft (CABG), balance CABG), pump and ischemic times and Bayes National Risk scores. The average volume returned to the patient from the HB was 8179/198 mL (1 SD). Average processing time was 11 min. The Hemobag®contained an average platelet count of 2309/80 K/mm3, fibrinogen concentration of 4139/171 mg/dl, total protein of 8.09/2.8 gm/dl, albumin of 4.49/1.2 gm/dl and hematocrit of 439/7%. Factor VII, IX and X levels in three HB contents averaged 259% greater than baseline. Substantial reductions were achieved in both allogeneic blood product avoidance and cost to the hospital with use of the HB.

Infusion of the Hemobag® concentrate appears to recover safely substantial proteins, clotting factor and cell concentration for all types of cardiac procedures, maintaining the security of a primed circuit.
A novel method of measuring cardiac output in infants following extracorporeal procedures: preliminary validation in a swine model
Authors: Melchior Richard , Darling Edward , Terry Bryan , Gunst Gordy , Searles Bruce
Published: November 2005

In infants, technologies for obtaining rapid, quantified measurements of cardiac output (CO) following weaning from cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation are not readily available. A new technique to measure CO based on ultrasound velocity dilution is described. It utilizes reusable probes placed on the extracorporeal circuit that permits convenient measurement of CO prior to decannulation. This report provides preliminary validation data in an animal model.

Three Yorkshire pigs (11-14 kg) were fully heparinized and cannulated via the right common carotid artery (cannula advanced to the aortic arch) and right atrium. Both the venous and arterial lines were instrumented with ultrasonic probes connected to a computer-monitoring system. A ‘stopcock bridge’ between the arterial and venous cannulas provided the access for saline injection and a controlled AV-shunt. For comparison, a vascular flow probe was fitted directly to the pulmonary artery (PA) in both animals and, for the larger animal, a PA catheter was inserted to obtain standard thermodilution measurements.

Linear regression analysis revealed a correlation between the CO by ultrasound dilution (CO UD) technique and the vascular probe and PA thermodilution techniques to be R2-0.94 and 0.81.

This pilot study demonstrated that the CO UD technique correlates to other benchmarks of CO measurements. This novel technology has specific application in the field of pediatric open heart surgery in that it would allow the surgeon to accurately and inexpensively measure the CO of neonatal and pediatric patients before and after surgical manipulation of the heart without the need for placement of additional catheters or probes.
Leukocyte removal efficiency of cell-washed and unwashed whole blood: an in vitro study
Authors: ten Brinke M J , Weerwind P W , Teerenstra S , Feron J CM , van der Meer W , Brouwer M HJ
Published: November 2005

Leukocyte filtration of the cardiopulmonary bypass (CPB) perfusate after cardiac surgery has evolved as an important technique to prevent effector functions mediated by activated leukocytes. However, little is known about the filtration efficiency. Therefore, an in vitro study was conducted to define the leukocyte removal rate of a transfusion leukocyte-depletion filter, using cell-washed and unwashed whole porcine blood. In addition, the influence of different cell-washing protocols on the elimination rate of blood cells (leukocytes and platelets) was investigated.

Fresh, diluted, pooled, heparinized, porcine blood was processed using either a high-flow (HF, n-5) or quality-wash (QW, n-5) protocol on a continuous auto-transfusion system, or was left unprocessed (control n-5). Thereafter, all samples were filtered using a transfusion leukocyte-depletion filter. Blood samples for measurement of hematocrit, white blood cell count, including leukocyte differentiation and platelet count, were taken before and after filtration. To compare the experimental groups, the removal rate was presented as the fraction of leukocytes or platelets removed per plasma volume.

Cell washing significantly altered the fraction of leukocytes removed per plasma volume when compared to unprocessed blood (2.07 and 2.36 in the HF and QW groups, respectively, versus 1.34 in the control group, p-0.008 for both). No statistically significant difference in leukocyte removal rate was observed between the different cell-washing protocols. The leukocyte differential count showed that, during all experiments, the neutrophils were removed most efficiently (99.7%). Overall, significantly more platelets were depleted after cell washing compared to the control group (1.47 and 1.60 in the HF and QW groups, respectively, versus 1.12 in the control group, p-0.008 and 0.032, respectively). Furthermore, the amount of blood that could be filtered using a single pass technique did not significantly differ between the experimental groups. However, a larger variation in the total amount of filtered blood was observed in the unprocessed group (5709/398 mL) compared to the cell-washed groups (3609/42 and 4309/97 mL in the HF and QW groups, respectively).

In conclusion, blood processing with an auto-transfusion system significantly enhances the leukocyte and platelet removal efficiency of the transfusion leukocyte-depletion filter that was studied. In particular, neutrophils were efficiently removed.
An overview of methods for interval-censored data with an emphasis on applications in dentistry
Authors: Lesaffre Emmanuel , Komárek Arnošt , Declerck Dominique
Published: November 2005

Interval-censored time-to-event data occur in many medical areas, with dentistry or AIDS research being typical representatives. This article reviews methods for the analysis of such data, with an emphasis on the use of the accelerated failure time (AFT) model. A flexible AFT model (avoiding parametric assumptions on the distribution of the error term) is described in greater detail and is used to solve a typical dental question in a longitudinal oral health study.
A multilevel modelling solution to mathematical coupling
Authors: Blance Andrew , Tu Yu-Kang , Gilthorpe Mark S
Published: November 2005

Owing to mathematical coupling, statistical analyses relating change to baseline values using correlation or regression are erroneous, where the statistical procedure of testing the null hypothesis becomes invalid. Alternatives, such as Oldham’s method and the variance ratio test, have been advocated, although these are limited in the presence of measurement errors with non-constant variance. Furthermore, such methods prohibit the consideration of additional covariates (e.g., treatment group within trials) or confounders (e.g., age and gender). This study illustrates the more sophisticated approach of multilevel modelling (MLM) which overcomes these limitations and provides a comprehensive solution to the analysis of change with respect to baseline values. Although mathematical coupling is widespread throughout applied research, one particular area where several studies have suggested a strong relationship between baseline disease severity and treatment effect is guided tissue regeneration (GTR) within dental research. For illustration, we use GTR studies where the original data were found to be available in the literature for reanalysis. We contrast the results from an MLM approach and Oldham’s method with the standard (incorrect) approach that suffers from mathematical coupling. MLM provides a robust solution when relating change to baseline and is capable of simultaneously dealing with complex error structures and additional covariates and/or potential confounders.
A Bayesian analysis of amalgam restorations in the Royal Air Force using the counting process approach with nested frailty effects
Authors: Manda Samuel OM , Gilthorpe Mark S , Tu Yu-Kang , Blance Andrew , Mayhew Martin T
Published: November 2005

Survival analysis methods are increasingly used in dental research to measure risk of tooth eruption and caries as well as life spans of amalgam restorations. Analyses have been extended to account for lack of independence in the data, which arises from the clustering of observations within units such as tooth-surfaces, teeth and subjects. There are various analytical strategies and modelling approaches now available to us in dealing with clustered dental data. In this article, the modelling strategy of Cox’s proportional hazards regression is formulated using the counting process approach, which can easily be extended to include time-variant covariates as well as nested random frailty effects. A semi-parametric Bayesian method is presented for the analysis of the proposed model. The methodology is applied to an analysis of nested clustered data on life-span of amalgam restorations in the UK Royal Air Force. These data have previously been analysed using a non-Bayesian approach. The Gibbs sampler, a Markov chain Monte Carlo method, is used to generate samples from the marginal posterior distribution of the parameters of this Bayesian model.
Endpoints and survival analysis for successful osseointegration of dental implants
Authors: Gerds Thomas A , Vogeler Michael
Published: November 2005

We review and adapt modern survival analysis adapted for evaluating the success of dental implants is reviewed. A defined composite success criterion is a valuable tool for assessing new developments of dental implants. However, several inaccuracies are detected in the relevant dental literature. The Kaplan-Meier estimator is distinguished from ad-hoc life table methods and crude cumulative percentages, and generally, the usage of confidence intervals is emphasized. This article reviews the definition of implant success also. For the example of longitudinal measurements of the peri-implant bone level, it is shown how to derive success probabilities by time-to-event analysis. It is concluded that advanced statistical methods and well-defined endpoints are needed to achieve meaningful and comparable results. The article is illustrated using the data of a familiar implant system (TPS-SteriOss®).
Group sequential testing in dental clinical trials with longitudinal data on multiple outcome variables
Authors: Leroux Brian G , Mancl Lloyd A , DeRouen Timothy A
Published: November 2005

In this article, methods are proposed for design and analysis of clinical trials that gather longitudinal data on multiple outcome variables. A valid test of the null hypothesis of no treatment group differences can be obtained for any choice of a working alternative hypothesis and a working covariance matrix for the outcome variables. Increased power can be achieved by accurate modeling of the true treatment effect and covariance structure. Implementation of the procedure is simple using existing software for generalized estimating equations. The procedure is an extension of the ‘derived variable’ technique (univariate analysis applied to a linear combination of the outcome variables) and also of O’Brien’s generalized least squares test. The procedure is extended to allow sequential testing using an arbitrary division of the total type I error rate among repeated hypothesis tests. The methods are illustrated by the design of a study on the safety of dental amalgam fillings, which served as the motivation for the research.
Emergency Ultrasound and Urinalysis in the Evaluation of Flank Pain
Authors: Gaspari Romolo J. , Horst Kurt
Published: November 2005

Objectives: To determine the sensitivity and specificity of limited emergency ultrasonography of the kidney in diagnosing renal colic. Methods: This was a prospective observational trial from December 2001 to December 2003 at a suburban emergency department. Patients who presented with flank pain suspicious for renal colic were enrolled. Exclusion criteria included fever, trauma, known current kidney stone, unstable vital signs, and inability to provide consent. All patients underwent sequential emergency ultrasonography and computed tomography of the kidneys and bladder. Data were analyzed using chi‐square analysis. The primary outcome was the sensitivity and specificity of ultrasonography. Results were also stratified for presence of hematuria. Results: Fifty‐eight of the 104 patients enrolled in the study were diagnosed with renal colic. The overall sensitivity and specificity of bedside ultrasonography for the detection of hydronephrosis were 86.8 (95% confidence interval [CI] = 78.8 to 92.3) and 82.4 (95% CI = 74.1 to 88.1), respectively. In patients with hematuria, hydronephrosis by emergency ultrasonography demonstrated a sensitivity and specificity of 87.8 (95% CI = 80.3 to 92.5) and 84.8 (95% CI = 73.7 to 91.9), respectively. In 55 of the cases, the initial computed tomograph was read by a resident and later re‐read by an attending physician. Using the reading of the attending physician as the criterion standard resulted in a sensitivity and specificity of 83.3 (95% CI = 73.2 to 88.0) and 92.0 (95% CI = 79.9 to 97.6), respectively. Conclusions: Emergency ultrasonography of the kidneys shows very good sensitivity and specificity for diagnosing renal colic in patients with flank pain and hematuria.