Association between ICAM-1 Gly-Arg polymorphism and renal parenchymal scarring following childhood urinary tract infection

Renal parenchymal scarring (RPS) following urinary tract infection (UTI) is an important cause of renal morbidity in children. Studies have shown that the intensity of the inflammatory response following infection is related to the risk of RPS. However, genetic variability in this response has not been studied. Adhesion molecules play a crucial role in leucocyte recruitment following infection, and polymorphisms have been reported in the genes for key cell adhesion molecules. We have investigated the possibility that children who develop RPS following UTI may exhibit altered genotype or allele frequencies for polymorphisms of the intercellular adhesion molecule-1 (ICAM-1) (exons 4 and 6), E-selectin (exons 2 and 4), platelet endothelial cell adhesion molecule-1 (PECAM-1) (exon 3) and CD11b (3'UTR) genes, which may predict outcome of UTI. DNA was isolated from 99 children shown to have developed RPS, 43 children with no evidence of scarring (NS) following UTI and 170 healthy controls. Genotyping was performed by restriction fragment length polymorphism (RFLP) analysis. When the RPS group was compared with the NS group, there was a significant reduction in the frequency of the ICAM-1 exon 4 A allele (10.6 vs. 21.3%, respectively, chi2 = 6.01, P = 0.014). There was no significant difference in either allele or genotype frequency for any of the other polymorphisms studied. These data suggest that the A allele of the ICAM-1 exon 4 polymorphism may protect against the risk of RPS following UTI and may participate in the regulation of the inflammatory response following UTI.

Determination of the pH of peri-implant crevicular fluid in successful and failing dental implant sites: A pilot study

The aims of this pilot study were to assess if a standard technique which is used to determine the pH of dental plaque around natural teeth (the 'touch electrode' technique) could be modified for use to determine the pH of crevicular fluid around dental implants, and to evaluate any possible changes in the peri-implant crevicular fluid pH in successful and failing implants. pH measurements of a sample of subjects' (n=17) peri-implant crevicular fluid of both successful and failing dental implants present in the same oral cavities were performed using iridium/iridium oxide (Beetrode) electrodes with 100 microm sensing tips, connected to an Orion 720 A pH meter. The technique appeared to be satisfactory for the purpose intended. The mean pH of the successful implants was 6.80 [STD+/-0.4; 95% confidence intervals (CI), 6.50-7.0], and that for the failing dental implants was 7.20 (STD+/-0.6; 95% CI, 6.90-7.50). The results showed that the technique described could be satisfactorily used to determine the pH of peri-implant crevicular fluid at dental implant sites, and that there was a significant difference between the pH of successful and failing dental implants (P<0.05). However, the results obtained should be interpreted with caution in view of the small sample size used in this pilot study.

Mutation scanning of the NF2 gene: an improved service based on meta-PCR/sequencing, dosage analysis, and loss of heterozygosity analysis

We describe the development and implementation of a neurofibromatosis type 2 (NF2) mutation scanning service based on novel techniques. All 17 exons of the NF2 gene are amplified in four polymerase chain reaction (PCR) reactions, using the meta-PCR technique to link the NF2 exons into chimeric concatamers. The meta-PCR products are then scanned for point mutations by direct sequencing. A four-exon dosage assay is used to test for large deletion/duplication mutations. In certain cases when tumour studies are necessary, these techniques are also combined with loss of heterozygosity analysis with three highly polymorphic microsatellite markers located within or close to the NF2 gene. Over a period of 2 years, we have applied these techniques in a service setting to the analysis of 271 patient samples (245 lymphocyte DNA; 26 schwannoma DNA). Meta-PCR and sequencing identified 90 point mutations in the 271 blood and tumor samples, 48 of which have not been reported previously. Dosage analysis identified large deletions in 12 of the lymphocyte DNA samples. In addition, over 84% of mutations were identified in 23 schwannoma DNA samples in which complete analysis was possible. Adoption of this novel strategy has increased the overall mutation detection rate in familial NF2 cases to 88% and sporadic NF2 cases to 59%. It has also allowed us to decrease our reporting turnaround times, and because of a low overall failure rate, permitted the running of an efficient and cost-effective service.

Differential increase in taurine levels by low-dose ethanol in the dorsal and ventral striatum revealed by microdialysis with on-line capillary electrophoresis

Ethanol increases taurine efflux in the nucleus accumbens or ventral striatum (VS), a dopaminergic terminal region involved in positive reinforcement. However, this has been found only at ethanol doses above 1 g/kg intraperitoneally, which is higher than what most rats will self-administer. We used a sensitive on-line assay of microdialysate content to test whether lower doses of ethanol selectively increase taurine efflux in VS as opposed to other dopaminergic regions not involved in reinforcement (e.g., dorsal striatum; DS). Adult male rats with microdialysis probes in VS or DS were injected with ethanol (0, 0.5, 1, and 2 g/kg intraperitoneally), and the amino acid content of the dialysate was measured every 11 sec using capillary electrophoresis and laser-induced fluorescence detection. In VS, 0.5 g/kg ethanol significantly increased taurine levels by 20% for 10 min. A similar increase was seen after 1 g/kg ethanol, which lasted for about 20 min after injection. A two-phased taurine efflux was observed with the 2.0 g/kg dose, where taurine was increased by 2-fold after 5 min but it remained elevated by 30% for at least 60 min. In contrast, DS exhibited much smaller dose-related increases in taurine. Glycine, glutamate, serine, and gamma-aminobutyric acid were not systematically affected by lower doses of ethanol; however, 2 g/kg slowly decreased these amino acids in both brain regions during the hour after injection. These data implicate a possible role of taurine in the mechanism of action of ethanol in the VS. The high sensitivity and time resolution afforded by capillary electrophoresis and laser-induced fluorescence detection will be useful for detecting subtle changes of neuronally active amino acids levels due to low doses of ethanol.

Steroid-sensitive nephrotic syndrome and vascular endothelial growth factor gene polymorphisms

Genetic polymorphisms have been recognized as important determinants of gene expression. Three common single nucleotide polymorphisms have been identified in the promoter and 5' untranslated region of the vascular endothelial growth factor (VEGF) gene: -460 C --> T, -141 A --> C and +405 G --> C. As VEGF has been postulated to play a role in the pathogenesis of childhood steroid-sensitive nephrotic syndrome (SSNS), this study tested the hypothesis that VEGF genotype may be associated with susceptibility to SSNS. We examined the genotype frequencies of these polymorphisms in a total of 116 children with SSNS and 150 control subjects, using polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). There were no statistically significant differences in any of the genotype frequencies between SSNS patients and controls. We conclude that VEGF -460, -141 and +405 genotypes are not associated with susceptibility to childhood SSNS.

Implant complications and failures: the fixed prosthesis

The implant-retained fixed prosthesis has been advocated as an effective restoration offering significant benefits over conventional prosthetics. The success of treatment depends on careful pre-surgical planning and prosthesis design. This paper outlines some common complications encountered during the planning, fabrication and maintenance of both large and small fixed prostheses and suggests how these complications can be minimized.

A PCR-RFLP typing method for adhesion molecule gene polymorphisms and allele frequencies in a normal UK population

We report simple and reproducible PCR-RFLP typing methods for the polymorphisms in the ICAM-1, E-selectin and PECAM-1 genes. The genotype and allele frequencies detected in a normal UK population did not deviate significantly from the Hardy-Weinberg equilibrium; neither did they differ from frequencies previously reported using SSP or SSCP methods.

Capillary LC-MS2 at the attomole level for monitoring and discovering endogenous peptides in microdialysis samples collected in vivo

Fused-silica capillary LC columns (25-microm i.d.) with 3-microm-i.d. integrated electrospray emitters interfaced to a quadrupole ion trap mass spectrometer were evaluated for high-sensitivity LC-MS2. Column preparation involved constructing frits by in situ photopolymerization of glycidyl methacrylate and trimethylolpropane trimethacrylate, preparing the electrospray emitter by pulling the column outlet to a fine tip with a CO2 laser puller, and slurry-packing the column with 5-microm reversed-phase particles. Large-volume injections were facilitated by an automated two-pump system that allowed high-flow rates for sample loading and low-flow rates for elution. Small electrospray emitters, low elution flow rates, and optimization of gradient steepness allowed a detection limit of 4 amol, corresponding to 2 pM for 1.8 microL injected on-column, for a mixture of peptides dissolved in artificial cerebral spinal fluid. The system was coupled on-line to microdialysis sampling and was used to monitor and discover endogenous neuropeptides from the globus pallidus of anesthetized male Sprague-Dawley rats. Time-segmented MS2 scans enabled simultaneous monitoring of Met-enkephalin, Leu-enkephalin, and unknown peptides. Basal dialysate levels of Met-enkephalin and Leu-enkephalin were 60 +/- 30 and 70 +/- 20 pM while K+-stimulated levels were 1,900 +/- 500 and 1,300 +/- 300 pM, respectively (n = 7). Data-dependent and time-segmented MS2 scans revealed several unknown peptides that were present in dialysate. One of the unknowns was identified as peptide I(1-10) (SPQLEDEAKE), a novel product of preproenkephalin A processing, using MS2, MS3, and database searching.

Identification and characterisation of a developmentally regulated mammalian gene that utilises -1 programmed ribosomal frameshifting

Translational recoding of mRNA through a -1 ribosomal slippage mechanism has been observed in RNA viruses and retrotransposons of both eukaryotes and prokaryotes. Whilst this provides a potentially powerful mechanism of gene regulation, the utilization of -1 translational frameshifting in regulating mammalian gene expression has remained obscure. Here we report a mammalian gene, Edr, which provides the first example of -1 translational recoding in a eukaryotic cellular gene. In addition to bearing functional frameshift elements that mediate expression of distinct polypeptides, Edr bears both CCHC zinc-finger and putative aspartyl protease catalytic site retroviral-like motifs, indicative of a relic retroviral-like origin for Edr. These features, coupled with conservation of Edr as a single copy gene in mouse and man and striking spatio-temporal regulation of expression during embryogenesis, suggest that Edr plays a functionally important role in mammalian development.

Rising incidence of post-transplant lymphoproliferative disease in kidney transplant recipients

BACKGROUND

The purpose of this study was to determine whether the incidence of post-transplant lymphoproliferative disease (PTLD) has been increasing in renal transplant recipients in this centre.

METHODS

Prospectively gathered data were analysed to establish trends in the epidemiology of PTLD in 1537 patients.

RESULTS

Overall, PTLD occurred in 2.3 per cent of renal transplant recipients. An increase in its incidence coincided with the introduction of cyclosporin in the 1980s. However, there was a further increase in the incidence of PTLD in the 1990s when the only change in immunosuppressive policy was the abandonment of pretransplantation blood transfusion. The latter increase was particularly pronounced in patients with early-onset PTLD in whom it presented within 600 days after transplantation.

CONCLUSION

The incidence of PTLD has been increasing in renal transplant recipients. The recent increase appears to be independent of cyclosporin and may reflect the reduction in pretransplant blood transfusion. Changes in the incidence of PTLD may also mirror changes in the epidemiology of non-Hodgkin lymphoma in the general population.

Combined transplantation of the heart, lung, and liver

Combined transplantation of the heart, lung, and liver may be indicated in patients with either end-stage respiratory failure complicated by advanced liver disease or end-stage liver failure complicated by advanced lung disease. A retrospective review of nine patients who underwent combined heart-lung-liver transplantation in Cambridge (1986-99) was carried out. The 1-year and 5-year actuarial survival was 56% and 42%, respectively. Combined heart-lung-liver transplantation is a feasible option for a few patients and has a 5-year survival similar to heart-lung transplantation but with a lower incidence of acute and chronic rejection.

Functional modeling of tight junctions in intestinal cell monolayers using polyethylene glycol oligomers

Despite significant advances in the characterization of tight junction (TJ) proteins, little is known about how molecular changes relate to function due primarily to the limitations of conventional paracellular probes. To address this, the paracellular pathway in Caco-2 and T84 cell lines was profiled by measuring the permeabilities of 24 polyethylene glycols (PEG) of increasing molecular radius (3.5--7.4 A) analyzed by mass spectrometry. When combined with a paracellular sieving model, these data provided quantitative descriptors of the pathway under control conditions and after exposure to TJ modulators. PEG profiles in both cell lines conformed to a biphasic process involving a restrictive pore (radius 4.3--4.5 A) and a nonrestrictive component responsible for permeability of larger molecules. PEG profiling revealed significant differences between the effects of EGTA and sodium caprate (C10). The restrictive component of EGTA-treated cells lost all size discrimination due to an increase in pore radius. Sodium caprate had no effect on pore radius but increased permeability via a different mechanism possibly involving increased numbers of functional pores. PEG profiling provides a useful tool for probing the functional regulation of the paracellular route.

Localization of CYP86B1 in the outer envelope of chloroplasts

CYP86B1 was cloned from a cDNA library and the protein expressed in E. coli. The protein gave the expected carbon monoxide difference spectrum. Using in vitro import assays with isolated pea chloroplasts, CYP86B1 was shown to be associated with the outer chloroplastic envelope membrane. This study provides the first direct evidence for a chloroplast-localized cytochrome P450-dependent monooxygenase.

Reliability of the lateral pull test and tilt test to assess patellar alignment in subjects with symptomatic knees: student raters

STUDY DESIGN

Test-retest reliability with blinded testers.

OBJECTIVES

To determine the inter- and intra-rater reliability of the lateral pull test and patellar tilt test.

BACKGROUND

If patellar malalignment can be detected by clinical examination, then condition-specific treatment interventions may be implemented in patients with patellofemoral pain syndrome. However, several clinical tests used to assess patellar mobility have recently been shown to have poor to fair reliability. Because the lateral pull test and the patellar tilt test are widely used clinically as diagnostic tests for patellofemoral pain syndrome but have not been previously tested for reliability, we examined these tests.

METHODS AND MEASURES

Fifty-two subjects (age range, 21-48 years) provided 95 knees (19 symptomatic and 76 asymptomatic) for assessment of the lateral pull test. Two testers, blinded to the presence or absence of symptoms, independently performed the lateral pull test in random order. Fifty-five subjects (age range, 22-42 years) provided 99 knees (73 asymptomatic and 26 symptomatic) for assessment of the patellar tilt test. Three blinded testers independently performed the patellar tilt test in random order. All subjects were tested and retested within 3-5 days. A kappa (kappa) statistic was used to assess the agreement of findings within each tester and between testers.

RESULTS

The kappa coefficients for intrarater reliability varied from 0.39 to 0.47 for the lateral pull test and from 0.44 to 0.50 for the patellar tilt test, while the coefficients for interrater reliability were 0.31 for the lateral pull test and varied from 0.20 to 0.35 for the tilt test.

CONCLUSIONS

Repeated lateral pull tests and patellar tilt tests had fair intrarater and poor interrater reliability. Our results suggest that care must be taken in placing too much emphasis on these tests when making clinical decisions.