'Aussie Normals': an a priori study to develop reference intervals in a healthy Australian population using the Beckman Coulter LH 750 Haematology Analyser as candidates for harmonised values.

Reference limits or intervals are important benchmarks or tools that help the clinician to distinguish between a result that is most likely to lie within a 'healthy' or diseased category. It has been suggested that a review of haematology reference intervals is long overdue. In this study we report on our findings for analytes routinely measured in a complete blood count (CBC) performed on the Beckman Coulter LH 750 analyser and an additional comparative study using the Beckman Coulter LH 750, the Sysmex XN and Abbott Sapphire. The results from the comparative study indicate that bias would not prevent harmonisation of reference intervals for these common haematology parameters. The results offered by the Aussie Normals study represent good candidates as the basis for harmonisation reference intervals.

'Aussie normals': an a priori study to develop clinical chemistry reference intervals in a healthy Australian population.

Development of reference intervals is difficult, time consuming, expensive and beyond the scope of most laboratories. The Aussie Normals study is a direct a priori study to determine reference intervals in healthy Australian adults. All volunteers completed a health and lifestyle questionnaire and exclusion was based on conditions such as pregnancy, diabetes, renal or cardiovascular disease. Up to 91 biochemical analyses were undertaken on a variety of analytical platforms using serum samples collected from 1856 volunteers. We report on our findings for 40 of these analytes and two calculated parameters performed on the Abbott ARCHITECTci8200/ci16200 analysers. Not all samples were analysed for all assays due to volume requirements or assay/instrument availability. Results with elevated interference indices and those deemed unsuitable after clinical evaluation were removed from the database. Reference intervals were partitioned based on the method of Harris and Boyd into three scenarios, combined gender, males and females and age and gender. We have performed a detailed reference interval study on a healthy Australian population considering the effects of sex, age and body mass. These reference intervals may be adapted to other manufacturer's analytical methods using method transference.

Angiotensinogen and transforming growth factor beta1: novel genes in the pathogenesis of Crohn's disease.

BACKGROUND: Angiotensin peptides may act locally as cytokines in several organ systems with elevated mucosal levels present in Crohn's disease. A variant in the angiotensinogen gene promoter results in increased peptide production, while transforming growth factor beta1 (TGFbeta1) codon 25 variants demonstrate variable peptide production, predisposing to fibrosis in several organs. AIMS: Conduct an Australian-based analysis of the angiotensinogen-6 variant in two independent inflammatory bowel disease (IBD) cohorts, and examine the role of angiotensinogen-6 and TGFbeta1 codon 25 variants in shaping Crohn's disease phenotype. METHODS: IBD Patients (Crohn's disease = 347, ulcerative colitis = 147) and CD families (n = 148) from two cohorts, together with 185 healthy controls were genotyped for angiotensinogen-6. Genotype-phenotype analyses were performed for both angiotensinogen-6 and TGFbeta1 codon 25. RESULTS: Angiotensinogen-6 AA genotype was significantly associated with Crohn's disease (p = 0.007, OR = 2.38, CI = 1.32-4.32) in cohort 1, but not in the smaller cohort 2 (p = 0.19). The association remained significant when the two cohorts were combined (p = 0.008), and in a TDT family analysis (p = 0.03). TGF 1 codon 25 was associated with stricturing Crohn's disease (p = 0.01, OR = 2.63, CI = 1.16-5.88) and a shorter time to intestinal resection (p = 0.06). CONCLUSIONS: The association of the angiotensinogen-6 variant with Crohn's disease supports a potential role for angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists in disease treatment.

Neutral amino acid transport in epithelial cells and its malfunction in Hartnup disorder.

Hartnup disorder is an autosomal recessive abnormality of renal and gastrointestinal neutral amino acid transport. A corresponding transport activity has been characterized in kidney and intestinal cells and named system B(0). The failure to resorb amino acids in this disorder is thought to be compensated by a protein-rich diet. However, in combination with a poor diet and other factors, more severe symptoms can develop in Hartnup patients, including a photosensitive pellagra-like skin rash, cerebellar ataxia and other neurological symptoms. Homozygosity mapping in a Japanese family and linkage analysis on six Australian pedigrees placed the Hartnup disorder gene at a locus on chromosome 5p15. This fine mapping facilitated a candidate gene approach within the interval, which resulted in the cloning and characterization of a novel member of the sodium-dependent neurotransmitter transporter family (B(0)AT1, SLC6A19) from mouse and human kidney, which shows all properties of system B(0). Flux experiments and electrophysiological recording showed that the transporter is Na(+) dependent and Cl(-) independent, electrogenic and actively transports most neutral amino acids. In situ hybridization showed strong expression in intestinal villi and in the proximal tubule of the kidney. Expression of B(0)AT1 was restricted to kidney, intestine and skin. A total of ten mutations have been identified in SLC6A19 that co-segregate with disease in the predicted recessive manner, with the majority of affected individuals being compound heterozygotes. These mutations lead to altered neutral amino acid transport function compared to the wild-type allele in vitro. One of the mutations occurs in members of the original Hartnup family described in 1956, thereby defining SLC6A19 as the 'Hartnup'-gene.

Association of TNF-alpha-857C with inflammatory bowel disease in the Australian population.

BACKGROUND: It is now well established that susceptibility to inflammatory bowel disease is in part genetic, with one localization on chromosome 6 (IBD3) having been replicated in a number of populations. A candidate in that region, TNF-alpha, contains polymorphisms in the promoter region that appear to be associated with disease. METHODS: More than 600 individuals from 170 multiplex IBD families were genotyped for four polymorphisms in the TNF-alpha gene and analysed for association. RESULTS AND CONCLUSION: A strong association was observed between transmission of the -857 C allele and disease. This effect was strongest in those families in which the NOD2 risk alleles are also segregating, supporting the existence of an interaction between IBD3 and IBD1 on chromosome 16.

CARD15/NOD2 risk alleles in the development of Crohn's disease in the Australian population.

We have previously reported strong evidence for linkage between IBD1 and Crohn's disease (CD) in Australian Crohn's disease families. Three risk alleles for Crohn's disease, (Arg702Trp (C/T), Gly908Arg (G/C) and 980fs981 (-/C), were recently identified in the CARD15/NOD2 gene on chromosome 16, implicating this as the IBD1 locus. Using a novel diagnostic PCR-RFLP, we have examined the frequency of these alleles in 205 multiplex IBD families, 107 sporadic Crohn's disease cases and 409 normal individuals. We demonstrate that the three risk alleles are more frequent in Crohn's disease, than in controls, with allelic frequencies of 0.11, 0.02 and 0.07 respectively. Heterozygosity for individual variants conferred a three-fold increase in risk for Crohn's disease while substantially higher risks were associated with being homozygous or compound heterozygous. Despite a significantly lower population allele frequency for the frameshift mutation than reported by other groups, we see a similar contribution by this allele to the risk of developing Crohn's disease. While the three risk alleles influence susceptibility to Crohn's disease in Australia, we show that these alleles do not fully explain the linkage evidence and suggest that there are very likely additional IBD1 susceptibility alleles yet to be described in Australian CD at the NOD2 locus. We also show a second linkage peak in Australian CD that provides some support for a second disease susceptibility locus on chromosome 16.

Association of TNF-α-857C with Inflammatory Bowel Disease in the Australian Population.

BACKGROUND: It is now well established that susceptibility to inflammatory bowel disease is in part genetic, with one localization on chromosome 6 (IBD3) having been replicated in a number of populations. A candidate in that region, TNF-α, contains polymorphisms in the promoter region that appear to be associated with disease. METHODS: More than 600 individuals from 170 multiplex IBD families were genotyped for four polymorphisms in the TNF-α gene and analysed for association. RESULTS AND CONCLUSION: A strong association was observed between transmission of the -857 C allele and disease. This effect was strongest in those families in which the NOD2 risk alleles are also segregating, supporting the existence of an interaction between IBD3 and IBD1 on chromosome 16.

Lymphedema after sentinel lymphadenectomy for breast carcinoma.

BACKGROUND: Initial studies of sentinel lymphadenectomy for patients with breast carcinoma confirmed that the status of the sentinel lymph nodes was an accurate predictor of the presence of metastatic disease in the axillary lymph nodes. Sentinel lymphadenectomy, as an axillary staging procedure, has risks of morbidity that have yet to be defined. METHODS: Patients were enrolled in a two-phase protocol that included concurrent data collection of patient characteristics and treatment variables. During the first (validation) phase, 72 patients underwent sentinel lymph node excision followed by a level I-II axillary dissection. After the technique had been established, the second phase commenced, during which only patients with positive sentinel lymph nodes underwent an axillary dissection. RESULTS: During the second phase, lymphedema was identified in 9 of 303 patients (3.0%) who underwent sentinel lymphadenectomy alone and in 20 of 117 patients (17.1%) who underwent sentinel lymphadenectomy combined with axillary dissection (P < 0.0001). Of 303 patients who underwent sentinel lymphadenectomy alone, 8 of 155 patients (5.1%) with tumors located in the upper outer quadrant and 1 of 148 patients (0.7%) with tumors in other locations developed lymphedema (P = 0.012). CONCLUSIONS: The risk of developing lymphedema after undergoing sentinel lymphadenectomy was measurable but significantly lower than after undergoing axillary dissection. Tumor location in the upper outer quadrant and postoperative trauma and/or infection were identifiable risk factors for lymphedema.

Analysis of Australian Crohn's disease pedigrees refines the localization for susceptibility to inflammatory bowel disease on chromosome 16.

A number of localizations for the putative susceptibility gene(s) have been identified for both Crohn's disease and ulcerative colitis. In a genome wide scan, Hugot et al. (1996) identified a region on chromosome 16 which appeared to be responsible for the inheritance of inflammatory bowel disease in a small proportion of families. Subsequent work has suggested that this localization is important for susceptibility to Crohn's disease rather than ulcerative colitis (Ohmen et al. 1996; Parkes et al. 1996). We investigated the contribution of this localization to the inheritance of inflammatory bowel disease in 54 multiplex Australian families, and confirmed its importance in a significant proportion of Crohn's disease families; we further refined the localization to a region near to D16S409, obtaining a maximum LOD score of 6.3 between D16S409 and D16S753.

Ulcerative colitis: a genetic disease?

A number of lines of evidence support the hypothesis that ulcerative colitis is an inherited disorder in a proportion of cases. First, there is a pattern of familial aggregation. Second, there are differences in the prevalence of the disease in different ethnic groups. Finally, the concordance rate in monozygotic twin pairs is higher than that of dizygotic twin pairs, although not as high as the concordance rates observed in Crohn's disease. Genetic models of the inheritance patterns suggest that ulcerative colitis is probably caused by one major gene, although that gene (or genes) remains to be identified. While at least one localization for susceptibility to Crohn's disease now seems certain, efforts to localize and characterize the susceptibility genes involved in the inheritance of ulcerative colitis are still underway. While the genes of the major histocompatibility complex have been imputed as causal in susceptibility to ulcerative colitis, a consensus of proof continues to elude us.

FH-Sydney 1 and 2: two novel frameshift mutations in exon 10 of the low-density lipoprotein receptor gene detected by heteroduplex formation.

We report two novel frameshift mutations in exon 10 of the low-density lipoprotein receptor gene that lead to familial hypercholesterolemia in separate lineages. The lesions, FH-Sydney 1 and FH-Sydney 2, were detected by a modified heteroduplex analysis of exon-specific polymerase chain reaction (PCR) amplified DNA, and characterized at the molecular level by sequencing. Restriction enzyme digestion of PCR amplified DNA confirmed the presence of the mutant alleles in affected family members and their absence in nonaffected family members in both lineages. FH-Sydney 1 is a 4-bp duplication at position 1373, while FH-Sydney 2 is a 2-bp deletion at position 1478. The predicted result of both mutations is the premature truncation of the receptor at stop codons generated downstream of the mutations. Neither mutation was detected in a survey of 54 unrelated familial hypercholesterolemia patients.

A rapid method for diagnosis of the Lebanese allele in the low-density lipoprotein receptor gene.

The Lebanese allele in the low-density lipoprotein receptor gene is one of the alleles which results in the disease familial hypercholesterolemia. We describe a rapid method for detection of the Lebanese allele, using the polymerase chain reaction to amplify part of exon 13, intron 14 and all of exon 14. The amplified DNA is then digested with HinfI which distinguishes between the normal and Lebanese alleles. A previously unidentified HinfI site is described in the intron. HinfI fragments are separated using polyacrylamide gel electrophoresis, and visualized by ethidium bromide staining.

Overdrive pacing: an approach to terminating ventricular tachycardia.

The article provides an introduction to the concept of temporary overdrive (or rapid-burst) ventricular pacing as a viable treatment option for the termination of recurrent monomorphic ventricular tachycardia. The procedure and principle of action are described as well as current indications for burst pacing. Nursing diagnoses applicable to the utilization of temporary ventricular pacemakers in overdrive pacing are delineated. Appropriate nursing interventions for each nursing diagnosis are discussed to provide guidelines for patient care management when implementing this method of pacing.

Guillain-Barré syndrome with secondary bilateral posterior interosseous nerve syndrome.

A case of Guillain-Barre syndrome (GBS), with secondary entrapment of the posterior interosseous nerve bilaterally, is presented. It is felt that this was caused by the edema associated with the primary GBS, which led to compression with an anatomically narrowed supinator space, previously aggravated by repetitive pronation-supination. Diagnosis of such cases demands careful serial physical examinations, electromyography, and nerve conduction velocity studies. Appropriate splinting and careful exercise to balance muscle return are essential in physiatric management.