The effects of mineral metabolism markers on renal transplant outcomes

BACKGROUND

Hyperparathyroidism is a common complication of chronic renal failure. A functioning kidney graft improves hyperparathyroidism but it can persist to some degree for years. Persistent hyperparathyroidism associated with hypercalcemia and hyperphosphatemia have been associated with poor graft and patient survivals. The purpose of the present work was to assess the association between calcium/phosphate mineral metabolism markers and graft outcomes.

PATIENTS AND METHODS

Among 389 renal transplantations performed in our center between January 2000 and June 2008, 331 patients had functioning grafts at 12 months, the subjects of this study. Measurements of intact parathyroid hormone (iPTH), serum calcium and phosphate, tubular phosphate reabsorption, and urinary calcium excretion were performed at 1, 3, 6, and 12 months. The mean follow-up was 84.0 ± 31.8 months.

RESULTS

During the follow-up period, 63 grafts (19.0%) were lost, 30 patients (9.0%) died, and 80 recipients (24.2%) presented at least one cardiovascular event. Univariate Cox proportional analysis showed high iPTH levels at 1 and 12 months after transplantation to not be associated with worse patient or graft survival or an higher risk of cardiovascular events. Serum phosphate and calcium concentrations as well as calcium-phosphate products during the first year after transplantation were not associated with graft and patient outcomes or cardiovascular events. However, serum calcium at 12 months showed an inverse association with graft survival after adjusting for other variables (hazard ratio 0.61; 95% confidence interval 0.40-0.94; P = .026).

CONCLUSIONS

iPTH levels and serum phosphate concentrations and calcium-phosphate products during the first year after transplantation were not associated with graft outcomes. The inverse association between adjusted calcium and graft survival should be studied further.

Defective lysosomal proteolysis and axonal transport are early pathogenic events that worsen with age leading to increased APP metabolism and synaptic Abeta in transgenic APP/PS1 hippocampus

BACKGROUND

Axonal pathology might constitute one of the earliest manifestations of Alzheimer disease. Axonal dystrophies were observed in Alzheimer's patients and transgenic models at early ages. These axonal dystrophies could reflect the disruption of axonal transport and the accumulation of multiple vesicles at local points. It has been also proposed that dystrophies might interfere with normal intracellular proteolysis. In this work, we have investigated the progression of the hippocampal pathology and the possible implication in Abeta production in young (6 months) and aged (18 months) PS1(M146L)/APP(751sl) transgenic mice.

RESULTS

Our data demonstrated the existence of a progressive, age-dependent, formation of axonal dystrophies, mainly located in contact with congophilic Abeta deposition, which exhibited tau and neurofilament hyperphosphorylation. This progressive pathology was paralleled with decreased expression of the motor proteins kinesin and dynein. Furthermore, we also observed an early decrease in the activity of cathepsins B and D, progressing to a deep inhibition of these lysosomal proteases at late ages. This lysosomal impairment could be responsible for the accumulation of LC3-II and ubiquitinated proteins within axonal dystrophies. We have also investigated the repercussion of these deficiencies on the APP metabolism. Our data demonstrated the existence of an increase in the amyloidogenic pathway, which was reflected by the accumulation of hAPPfl, C99 fragment, intracellular Abeta in parallel with an increase in BACE and gamma-secretase activities. In vitro experiments, using APPswe transfected N2a cells, demonstrated that any imbalance on the proteolytic systems reproduced the in vivo alterations in APP metabolism. Finally, our data also demonstrated that Abeta peptides were preferentially accumulated in isolated synaptosomes.

CONCLUSION

A progressive age-dependent cytoskeletal pathology along with a reduction of lysosomal and, in minor extent, proteasomal activity could be directly implicated in the progressive accumulation of APP derived fragments (and Abeta peptides) in parallel with the increase of BACE-1 and gamma-secretase activities. This retard in the APP metabolism seemed to be directly implicated in the synaptic Abeta accumulation and, in consequence, in the pathology progression between synaptically connected regions.

Regulation of the phosphatase calcineurin by insulin-like growth factor I unveils a key role of astrocytes in Alzheimer's pathology

Whether insulin-like growth factor I (IGF-I) signaling in Alzheimer's disease (AD) is beneficial or detrimental remains controversial. We now show that a competitive regulation by IGF-I of the phosphatase calcineurin in reactive, but not in quiescent astrocytes drives Alzheimer's pathology. Calcineurin de-phosphorylates the transcription factor Foxo3 in response to tumor necrosis factor-α (TNFα), an inflammatory cytokine increased in AD, activating nuclear factor-κB (NFκB) inflammatory signaling in astrocytes. In turn, IGF-I inactivates and displaces Foxo3 from calcineurin in TNFα-stimulated astrocytes by recruiting the transcription factor peroxisome proliferator-activated receptor-γ, and NFκB signaling is inhibited. This antagonistic mechanism reversibly drives the course of the disease in AD mice, even at advanced stages. As hallmarks of this calcineurin/Foxo3/NFκB pathway are present in human AD brains, treatment with IGF-I may be beneficial by antagonizing it.

Abnormal accumulation of autophagic vesicles correlates with axonal and synaptic pathology in young Alzheimer's mice hippocampus

Dystrophic neurites associated with amyloid plaques precede neuronal death and manifest early in Alzheimer's disease (AD). In this work we have characterized the plaque-associated neuritic pathology in the hippocampus of young (4- to 6-month-old) PS1(M146L)/APP(751SL) mice model, as the initial degenerative process underlying functional disturbance prior to neuronal loss. Neuritic plaques accounted for almost all fibrillar deposits and an axonal origin of the dystrophies was demonstrated. The early induction of autophagy pathology was evidenced by increased protein levels of the autophagosome marker LC3 that was localized in the axonal dystrophies, and by electron microscopic identification of numerous autophagic vesicles filling and causing the axonal swellings. Early neuritic cytoskeletal defects determined by the presence of phosphorylated tau (AT8-positive) and actin-cofilin rods along with decreased levels of kinesin-1 and dynein motor proteins could be responsible for this extensive vesicle accumulation within dystrophic neurites. Although microsomal Aβ oligomers were identified, the presence of A11-immunopositive Aβ plaques also suggested a direct role of plaque-associated Aβ oligomers in defective axonal transport and disease progression. Most importantly, presynaptic terminals morphologically disrupted by abnormal autophagic vesicle buildup were identified ultrastructurally and further supported by synaptosome isolation. Finally, these early abnormalities in axonal and presynaptic structures might represent the morphological substrate of hippocampal dysfunction preceding synaptic and neuronal loss and could significantly contribute to AD pathology in the preclinical stages.

Age-dependent accumulation of soluble amyloid beta (Abeta) oligomers reverses the neuroprotective effect of soluble amyloid precursor protein-alpha (sAPP(alpha)) by modulating phosphatidylinositol 3-kinase (PI3K)/Akt-GSK-3beta pathway in Alzheimer mouse model

Neurotrophins, activating the PI3K/Akt signaling pathway, control neuronal survival and plasticity. Alterations in NGF, BDNF, IGF-1, or insulin signaling are implicated in the pathogenesis of Alzheimer disease. We have previously characterized a bigenic PS1×APP transgenic mouse displaying early hippocampal Aβ deposition (3 to 4 months) but late (17 to 18 months) neurodegeneration of pyramidal cells, paralleled to the accumulation of soluble Aβ oligomers. We hypothesized that PI3K/Akt/GSK-3β signaling pathway could be involved in this apparent age-dependent neuroprotective/neurodegenerative status. In fact, our data demonstrated that, as compared with age-matched nontransgenic controls, the Ser-9 phosphorylation of GSK-3β was increased in the 6-month PS1×APP hippocampus, whereas in aged PS1×APP animals (18 months), GSK-3β phosphorylation levels displayed a marked decrease. Using N2a and primary neuronal cell cultures, we demonstrated that soluble amyloid precursor protein-α (sAPPα), the predominant APP-derived fragment in young PS1×APP mice, acting through IGF-1 and/or insulin receptors, activated the PI3K/Akt pathway, phosphorylated the GSK-3β activity, and in consequence, exerted a neuroprotective action. On the contrary, several oligomeric Aβ forms, present in the soluble fractions of aged PS1×APP mice, inhibited the induced phosphorylation of Akt/GSK-3β and decreased the neuronal survival. Furthermore, synthetic Aβ oligomers blocked the effect mediated by different neurotrophins (NGF, BDNF, insulin, and IGF-1) and sAPPα, displaying high selectivity for NGF. In conclusion, the age-dependent appearance of APP-derived soluble factors modulated the PI3K/Akt/GSK-3β signaling pathway through the major neurotrophin receptors. sAPPα stimulated and Aβ oligomers blocked the prosurvival signaling. Our data might provide insights into the selective vulnerability of specific neuronal groups in Alzheimer disease.

Scaling up Heuristic Planning with Relational Decision Trees

Current evaluation functions for heuristic planning are expensive to compute. In numerous planning problems these functions provide good guidance to the solution, so they are worth the expense. However, when evaluation functions are misguiding or when planning problems are large enough, lots of node evaluations must be computed, which severely limits the scalability of heuristic planners. In this paper, we present a novel solution for reducing node evaluations in heuristic planning based on machine learning. Particularly, we define the task of learning search control for heuristic planning as a relational classification task, and we use an off-the-shelf relational classification tool to address this learning task. Our relational classification task captures the preferred action to select in the different planning contexts of a specific planning domain. These planning contexts are defined by the set of helpful actions of the current state, the goals remaining to be achieved, and the static predicates of the planning task. This paper shows two methods for guiding the search of a heuristic planner with the learned classifiers. The first one consists of using the resulting classifier as an action policy. The second one consists of applying the classifier to generate lookahead states within a Best First Search algorithm. Experiments over a variety of domains reveal that our heuristic planner using the learned classifiers solves larger problems than state-of-the-art planners.

Utilization of elderly kidney donors (>70 years) does not affect graft survival in the medium term

BACKGROUND

The need for organs for renal transplantation has encouraged the use of grafts from increasingly older donors. Earlier studies performed in Spain have shown the suitability of donors aged 60-65 years. In this single-center study, we evaluated our results using donors >70 years old.

METHODS

We evaluated 401 primary transplantations performed from January 2000 to December 2009. Their initial immunosuppression was a tacrolimus-based (n = 324), cyclosporine-based (n = 70) or calcineurin inhibitor-free (n = 7) regimen patients. Recipients were classified according to the donors age: <50 (42.6%); 50-70 (39.7%) and >70 (17.5%) years.

RESULTS

There were no differences in recipient or donor gender, time on dialysis, cold ischemia, delayed graft function, or acute rejection episodes. However, the mean age was higher among patients who received grafts from donors >70 years old; 42.5 ± 12.4 years for <50, 58.1 ± 8.2 years for 50-70, and 65.7 ± 7.2 years for >70; (P = .000). The serum creatinine at 12 months was increased according to the age of the donor; 1.4 ± 0.6, 1.8 ± 0.6, 70 and 1.7 ± 0.5 mg/dL, respectively (P = .001). The graft survival rates at 5 years were 81%, 74%, and 70%, respectively (P = .519). Upon multivariate analysis only HLA-DR mismatches, delayed graft function, and acute rejection episodes were associated with graft loss. Patient survival rates (86%) at 5 years were similar among recipients from donors aged 50-70 and >70 years, but higher (96%) for those who received a graft from a donor <50 years (P = .003).

CONCLUSIONS

Nearly 20% of donors were >70 years old in our study. Their kidneys displayed excellent short-term outcomes.

Calretinin interneurons are early targets of extracellular amyloid-beta pathology in PS1/AbetaPP Alzheimer mice hippocampus

Specific neuronal networks are preferentially affected in the early stages of Alzheimer's disease (AD). The distinct subpopulations of hippocampal inhibitory GABAergic system have been shown to display differential vulnerability to neurodegeneration in AD. We have previously reported a substantial loss of SOM/NPY interneurons, whereas those expressing parvalbumin were unaltered, in the hippocampus of 6 month-old PS1/AbetaPP transgenic mice. In the present study, we now investigated the pathological changes of hippocampal calretinin (CR) interneurons in this PS1/AbetaPP model from 2 to 12 months of age. The total number of CR-immunoreactive inhibitory cells was determined by stereology in CA1 and CA2/3 subfields. Our findings show a substantial decrease (35%-45%) of CR-positive interneurons in both hippocampal subfields of PS1/AbetaPP mice at very early age (4 months) compared to age-matched control mice. This decrease was accompanied by a reduced CR mRNA content as determined by quantitative RT-PCR. However, the number of another hippocampal CR-positive population (belonging to Cajal-Retzius cells) was not affected. The selective early loss of CR-interneurons was parallel to the appearance of extracellular Abeta deposits, preferentially in CR-axonal fields, and the formation of dystrophic neurites. This specific GABAergic subpopulation plays a crucial role in the generation of synchronous rhythmic activity in hippocampus by controlling other interneurons. Therefore, early alterations of hippocampal inhibitory functionality in AD, caused by select CR-cells neurodegeneration, could result in cognitive impairments seen in initial stages of the disease.

Extracellular amyloid-beta and cytotoxic glial activation induce significant entorhinal neuron loss in young PS1(M146L)/APP(751SL) mice

Here we demonstrated that extracellular, not intracellular, amyloid-beta (Abeta) and the associated cytotoxic glial neuroinflammatory response are major contributors to early neuronal loss in a PS1xAPP model. A significant loss of principal (27%) and SOM/NPY (56-46%) neurons was found in the entorhinal cortex at 6 months of age. Loss of principal cells occurred selectively in deep layers (primarily layer V) whereas SOM/NPY cell loss was evenly distributed along the cortical column. Neither layer V pyramidal neurons nor SOM/NPY interneurons displayed intracellular Abeta immunoreactivity, even after formic acid retrieval; thus, extracellular factors should be preferentially implicated in this selective neurodegeneration. Amyloid deposits were mainly concentrated in deep layers at 4-6 months, and of relevance was the existence of a potentially cytotoxic inflammatory response (TNFalpha, TRAIL, and iNOS mRNAs were upregulated). Moreover, non-plaque associated activated microglial cells and reactive astrocytes expressed TNFalpha and iNOS, respectively. At this age, in the hippocampus of same animals, extracellular Abeta induced a non-cytotoxic glial activation. The opposite glial activation, at the same chronological age, in entorhinal cortex and hippocampus strongly support different mechanisms of disease progression in these two regions highly affected by Abeta pathology.

Collaborative annotation of genes and proteins between UniProtKB/Swiss-Prot and dictyBase

UniProtKB/Swiss-Prot, a curated protein database, and dictyBase, the Model Organism Database for Dictyostelium discoideum, have established a collaboration to improve data sharing. One of the major steps in this effort was the ‘Dicty annotation marathon’, a week-long exercise with 30 annotators aimed at achieving a major increase in the number of D. discoideum proteins represented in UniProtKB/Swiss-Prot. The marathon led to the annotation of over 1000 D. discoideum proteins in UniProtKB/Swiss-Prot. Concomitantly, there were a large number of updates in dictyBase concerning gene symbols, protein names and gene models. This exercise demonstrates how UniProtKB/Swiss-Prot can work in very close cooperation with model organism databases and how the annotation of proteins can be accelerated through those collaborations.

Inter-individual variability in the expression of the mutated form of hPS1M146L determined the production of Abeta peptides in the PS1xAPP transgenic mice

The detection of the early phenotypic modifications of Alzheimer's disease (AD) models is fundamental to understand the progression and identify pharmacologic targets of this pathology. However, a large variability within different models and between age-matched mice from the same model has been observed. This variability could be due to heterogeneity in the Abeta production. Present results showed the existence of a large variability in the Abeta deposition in both hippocampus and cortex in 6-month-old PS1xAPP mice. This variability was not due to the expression of hAPP751SL, however, linear relationship between hPS1M146L mRNA and Abeta production was identified. The Abeta content was related to the incorporation of the hPS1M146L into functional gamma-secretase complexes, detected by the presence of the corresponding human or endogenous PS1-CTFs. Animals expressing low amount of hPS1M146L mRNA, displayed low hPS1-CTF incorporation and produced a low amount of Abeta peptides. Conversely, mice with relatively high hPS1 mRNA expression displayed high hPS1-CTF and high Abeta deposition. Furthermore, the Abeta total and Abeta1-42 content was increased dramatically by the expression of hPS1M146L (as compared with transgenic APPsl littermates). Therefore, variations in the expression of transgenic form of hPS1M146L in this model, or even between different models, influenced strongly the incorporation of the mutated PS1 into functional gamma-secretase complexes, the production of Abeta peptides and, in consequence, the detrimental effects of Abeta peptides. These data might implicate an "apparent gain-of-function" of the gamma-secretase complex by the expression of the mutated PS1M146L.

Early neuropathology of somatostatin/NPY GABAergic cells in the hippocampus of a PS1×APP transgenic model of Alzheimer's disease

At advanced stages, Alzheimer's disease (AD) is characterized by an extensive neuronal loss. However, the early neurodegenerative deficiencies have not been yet identified. Here we report an extensive, selective and early neurodegeneration of the dendritic inhibitory interneurons (oriens-lacunosum moleculare, O-LM, and hilar perforant path-associated, HIPP, cells) in the hippocampus of a transgenic PS1xAPP AD model. At 6 months of age, from 22 different pre- and postsynaptic mRNA markers tested (including GABAergic, glutamatergic and cholinergic markers), only the expression of somatostatin (SOM) and NPY neuropeptides (O-LM and HIPP markers) displayed a significant decrease. Stereological cell counting demonstrated a profound diminution (50-60%) of SOM-immunopositive neurons, preceding the pyramidal cell loss in this AD model. SOM population co-expressing NPY was the most damaged cell subset. Furthermore, a linear correlation between SOM and/or NPY deficiency and Abeta content was also observed. Though the molecular mechanism of SOM neuronal loss remains to be determined, these findings might represent an early hippocampal neuropathology. Therefore, SOM and NPY neuropeptides could constitute important biomarkers to assess the efficacy of potential early AD treatments.

Effect of maternal cholestasis and treatment with ursodeoxycholic acid on the expression of genes involved in the secretion of biliary lipids by the neonatal rat liver

In juvenile rats born from mothers with obstructive cholestasis during pregnancy (OCP), transient latent cholestasis together with alterations in the secretion of biliary lipids have been reported. Here we investigated whether the expression of genes involved in this function is already modified at birth and examined the effect of treating pregnant rats with ursodeoxycholic acid (UDCA; i.g., 60 microg/100 g b.w./day). Cholanemia was markedly higher in mothers with OCP, and was further increased by UDCA. In the Control pups, cholanemia increased after birth, whereas in OCP and OCP+UDCA pups, hypercholanemia decreased after birth. Steady-state mRNA levels in neonatal liver were measured by real-time quantitative RT-PCR. The expression of basolateral bile acid transporters was not affected by OCP and was unchanged (Oatp1/1a1 and Oatp4/1b2) or moderately increased (Ntcp and Oatp2/1a4) by UDCA. In both groups, the expression of ABC proteins was either not modified (Bsep, Bcrp and Mrp2) or enhanced (Mrp1 and Mrp3), that of phospholipid flippase Mdr2 was not changed, whereas that of cholesterol transporter Abcg5/Abcg8 was impaired. The expression of the nuclear receptor FXR was not affected by OCP or UDCA, whereas that of SHP and key enzymes in bile acid synthesis (Cyp7a1, Cyp8b1 and Cyp27) was increased in both groups. In conclusion, OCP affects the expression in the neonatal liver of genes involved in hepatobiliary function, which cannot be prevented, at this stage, by treating pregnant rats with UDCA, even though this treatment has been found to partially restore normal lipid secretion later during post-natal development.

A novel promoter polymorphism in the gene encoding complement component 5 receptor 1 on chromosome 19q13.3 is not associated with asthma and atopy in three independent populations

BACKGROUND

The inflammatory functions of complement component 5 (C5) are mediated by its receptor, C5R1, which is expressed on bronchial, epithelial, vascular endothelial and smooth muscle cells. A susceptibility locus for murine allergen-induced airway hyper-responsiveness was identified in a region syntenic to human chromosome 19q13, where linkage to asthma has been demonstrated and where the gene encoding C5R1 is localized.

OBJECTIVE

The aim of this study was to screen for novel polymorphisms in the C5R1 gene and to determine whether any identified polymorphisms are associated with asthma and/or atopy and whether they are functional.

METHODS

Single-nucleotide polymorphism (SNP) detection in the gene encoding C5R1 was performed by direct sequencing. Genotyping was performed in three populations characterized for asthma and/or atopy: (1) 823 German children from The Multicenter Allergy Study; (2) 146 individuals from Tangier Island, Virginia, a Caucasian isolate; and (3) asthma case-parent trios selected from 134 families (N=783) in Barbados. Functional studies were performed to evaluate differences between the wild-type and the variant alleles.

RESULTS

We identified a novel SNP in the promoter region of C5R1 at position -245 (T/C). Frequency of the -245C allele was similar in the German (31.5%) and Tangier Island (36.3%) populations, but higher in the Afro-Caribbean population (53.0%; P=0.0039 to <0.0001). We observed no significant associations between the -245 polymorphism and asthma or atopy phenotypes. Upon examination of the functional consequences of the -245T/C polymorphism, we did not observe any change in promoter activity.

CONCLUSION

This new marker may provide a valuable tool to assess the risk for C5a-associated disorders, but it does not appear to be associated with asthma and/or atopy.

Evaluation of a triple-lumen central venous heparin-coated catheter versus a catheter coated with chlorhexidine and silver sulfadiazine in critically ill patients

OBJECTIVE

To compare the incidence of catheter colonization and catheter-related bloodstream infections between heparin-coated catheters and those coated with a synergistic combination of chlorhexidine and silver sulfadiazine.

DESIGN

Randomized, controlled clinical trial.

SETTING

A 20-bed medical-surgical intensive care unit.

PATIENTS

A total of 180 patients requiring the insertion of a trilumen central venous catheter. INTERVENTIONS. Patients were randomized to receive either a trilumen heparin or chlorhexidine and silver sulfadiazine-coated catheter.

MEASUREMENTS

Catheter colonization was defined by a semiquantitative catheter tip culture yielding 15 or more colony-forming units or quantitative culture of 1,000 or more colony-forming units/ml. Catheter-related bloodstream infection as the isolation of the same microorganism from a peripheral blood culture and catheter tip.

RESULTS

A total of 260 catheters were cultured. Out of 132 heparin-coated catheters, 29 were colonized and out of 128 chlorhexidine and silver sulfadiazine-coated catheters, 13 were colonized ( p=0.03), relative risk RR=2.16 (1.18-3.97). This represents an incidence of 23.5 and 11.5 episodes of catheter colonization per 1,000 catheter-days, respectively ( p=0.0059), RR=2.04 (1.05-3.84). Microorganisms isolated in catheter colonization from heparin-coated catheters were gram-positive cocci 23, gram-negative bacilli 7, and Candida spp 4. In chlorhexidine and silver sulfadiazine-coated catheters were gram-positive cocci 6 and gram-negative bacilli 11 ( p=0.009). The incidence of catheter-related bloodstream infections per 1,000 catheter-days was 3.24 in heparin-coated catheters and 2.6 in chlorhexidine and silver sulfadiazine-coated catheters ( p=0.79), RR=1.22 (0.27-5.43).

CONCLUSIONS

In critically ill patients the use of trilumen central venous catheters coated with chlorhexidine and silver sulfadiazine reduced the risk of catheter colonization due to prevention of gram-positive cocci and Candida spp.

Live liver donation: a prospective analysis of exclusion criteria for healthy and potential donors

INTRODUCTION

Living donor liver transplantation represents a controversial option to increase the donor pool.

DESIGN

Prospective and descriptive clinical study.

OBJECTIVE

(1) To identify risk factors (exclusion criteria) for live donation; (2) to determine the rate of recipients that benefit from a living donor.

METHODS

Between May 1995 (first adult-to-adult living donor liver transplantation in Spain) and November 2002, we evaluated 74 healthy volunteers and performed 12 living donor liver transplants (no donor mortality).

RESULTS

All actual donors and volunteers are alive and healthy. After a mean time of 3.2+/-0.5 weeks, 72% of potential donors were considered unsuitable for live donation. Exclusion criteria were grouped in three categories: (primary) donor safety reasons (68%); (secondary): ABO mismatch (17%) and (tertiary): cadaveric graft transplantation (15%). Consequently, just 43.7% of the recipients presenting to us with a potential living donor, did finally benefit from these organs. The mortality rate was 8.3% for 43 recipients presenting with a living donor in comparison to 15% for those who did not (321 recipients between May 1995 and November 2001).

CONCLUSIONS

ALDLT can benefit a significant number of recipients on the waiting list (43.7% of those presenting with a donor). The most frequent exclusion criteria concern donor safety, namely, unsuspected chronic liver diseases and unsuspected thrombophilic disorders.

The challenges of conducting clinical research: one research team's experiences

Conducting clinical research is an exciting and a rewarding endeavor. Each project is unique and, because of this uniqueness, research studies require considerable planning. Regardless of all the upfront planning, challenges will occur throughout the life of the study. Clinical research projects are rife with obstacles that range from the lack of administrative and physician support to subject attrition. Some of the challenges, such as subject dropout, are not unexpected, whereas other unanticipated issues can blindside a research team. This case study examines several such challenges experienced in one longitudinal study and presents the solutions engineered by the research team to keep the project on track.

Presence of granulocytic ehrlichia in ticks and serological evidence of human infection in La Rioja, Spain

In order to estimate the risks of human granulocytic ehrlichiosis (HGE) in an endemic area for Lyme disease in the North of Spain (La Rioja), we collected and investigated by PCR specific to the E. phagocytophila group DNA, a total of 6870 Ixodes ricinus ticks. We also used an indirect immunofluorescence (IFI) test to study the presence of antibodies to the HGE agent in 147 human serum samples including patients with Lyme disease (LD), forestry workers, and persons with history of previous tick bite. Fifty serum samples from healthy people resident in urban areas and with no history of tick-bite disorder and without tick exposure were used as controls. Four of 76 adults and 49 of 203 nymphs pools carried E. phagocytophila DNA. This result, and the finding of 1.4% of sera reacting in the IFI test confirms that this tick-borne agent is present in La Rioja, and that humans show evidence of contact with it. HGE should be considered in the differential diagnosis of flu-like syndromes in the study area in the north of Spain.

Anomalous coronary artery origin associated with bicuspid aortic valve in a patient with rheumatic mitral stenosis: a case report

A rare case of an anomalous left coronary artery arising from the right sinus of Valsalva associated with bicuspid aortic valve is presented. This case is unique because these congenital anomalies were associated with rheumatic mitral stenosis. This anomalous coronary origin was found at catheterization before balloon mitral valvuloplasty. The clinical significance of this finding is discussed.

Molecular cloning and expression patterns of mouse cartilage oligomeric matrix protein gene

OBJECTIVE

To develop transgenic mice harboring mutations in the COMP gene as animal models for pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), autosomal dominant disorders characterized by early onset osteoarthritis and epiphyseal abnormalities. As a first step in generating a mouse model for COMP mutations, we have cloned the cDNA of mouse COMP and examined its tissue expression pattern.

DESIGN

Total mRNA was isolated from the skeletal tissues of newborn C57BL/6j mice and used as a template for oligo(dT) first-strand cDNA synthesis. The cDNA was used for PCR amplification of COMP using three oligonucleotide primer pairs designed from the published rat COMP cDNA sequence. Nested PCR was used to complete the sequence between the amplified fragments. The entire cDNA was sequenced and the expression pattern of the corresponding transcripts examined by Northern hybridizations.

RESULTS

A full-length COMP cDNA was isolated. Analysis showed that the entire translated region of the mouse COMP gene is 2268 bp and the derived amino acid sequence shows 90% homology to human COMP. Of eight adult mouse non-cartilage tissues tested, COMP expression was detected only in testis.

Pemphigus vulgaris induced by D-penicillamine therapy in a patient with systemic sclerosis

D: -Penicillamine-induced pemphigus occurs infrequently, typically in patients with rheumatoid arthritis. We describe a patient with systemic sclerosis who experienced this complication 3 months after starting D -penicillamine therapy. Nikolsky's sign, histopathologic findings, and direct immunofluorescence all confirmed the diagnosis. Termination of disease progression required intravenous pulse glucocorticoids, azathioprine, and 3 courses of plasmapheresis. The presentation, treatment, and etiology of D -penicillamine-induced pemphigus are reviewed, and the incidence of this complication in scleroderma patients is examined.

Culture of Blomia tropicalis and IgE immunoblot characterization of its allergenicity

Blomia tropicalis is an important triggering factor for allergic diseases such as asthma, rhinitis and atopic dermatitis in tropical and subtropical regions, which climate favours the growth of this species. Our previous mite fauna study revealed that Blomia tropicalis is the most dominant species present in Singapore house dust The main objective of this study is to establish a mass culture of Blomia tropicalis for further characterization of the antigenic and molecular properties of this mite. Approximately one gram of mites could be obtained for every 300-gram of culture medium by culturing under natural condition with a mean annual temperature of 30 degrees C and a mean relative humidity of 80%, and harvested by modified Tullgren funnel. Allergen characterization by IgE immunoblot analysis with crude mite extracts showed some IgE reactivity differences between Blomia tropicalis mite extract from Singapore and Colombia. The possible reasons for these findings are the quality and source of the mite protein extracts used, or selective differences in the population under evaluation. Further, the atopic sera tested showed differences in the pattern and Intensity of IgE immunoblot reactivity to crude extracts of Blomia tropicalis and Dermatophagoides pteronyssinus, the other highly prevalent mite in Singapore. These data support the existence of species-specific allergens. In conclusion, we have been successful in setting up B. tropicalis mass cultures and have prepared extracts of high allergenicity.

A review of the collaborative exercises on DNA typing of the Spanish and Portuguese ISFH Working Group. International Society for Forensic Haemogenetics

Since 1992 the Spanish and Portuguese Working Group (GEP) of the International Society for Forensic Haemogenetics (ISFH) has been organizing collaborative exercises on DNA profiling with the aim of making progress on standardization and discussing technical and statistical problems in DNA analysis. A total of four exercises (GEP-92 to GEP-95) have been carried out until now. A consequence of these exercises was the creation of a quality control programme in Spain and Portugal in 1995 which was carried out simultaneously with the GEP-95 exercise. The number of participating laboratories increased from 10 in the first exercise (GEP-92) to 19 in the last exercise (GEP-95). Despite this increasing number of participating laboratories, results remained satisfactory. In the last exercises, all the laboratories used PCR-based DNA polymorphisms with an increasing number of markers obtaining good results. SLPs were used by only 30% of laboratories in the last two exercises but the results indicated a good level of expertise in most of these laboratories. The reasons for these successful results are the common use of the EDNAP protocol for SLP analysis and commercially available kits or common sequenced allelic ladders for PCR-based DNA polymorphisms.

Cloning and IgE binding of a recombinant allergen from the mite Blomia tropicalis, homologous with fatty acid-binding proteins

To characterize the allergens of Blomia tropicalis, a cDNA library was constructed and screened with allergic sera from asthmatic patients. One clone, Bt6, was subcloned and sequenced. The nucleotide sequence of 934 bp length shows a 390-bp reading frame which encodes a 130-amino acid protein with a MW 14.8 kD. No potential glycosylation site was found in the predicted protein. The inferred amino acid sequence has no homology to known allergens. It has a cytosolic fatty acid-binding protein (FABP) signature at 5-22 amino acid residues, 42.3% identity with the Sm14-FABP of Schistosoma mansoni and 36% identity with FABPs from rat, mouse, bovine and human. The protein was expressed as a GST fusion protein and the purified GST-Bt6 used for dot blot, RAST and RAST inhibition assays. The frequency of IgE binding of allergic sera to Bt6 was low (11%) and usually weak. One positive serum did, however, show strong reactivity by RAST and dot blot and Bt6 could inhibit 60% of the IgE binding of this serum to the B. tropicalis extract. These data show that Bt6 encodes a mite FABP with allergenic properties, which are pronounced in some atopic subjects.