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Biomedical subjects

M J Burt

Publications and source records attributed to M J Burt.

36 records · Page 2Linked to original sources
PubMed1997

Isolation and characterisation of cosmids to intervals within a 4.5Mb region at 6p21.3.

The gene responsible for hereditary haemochromatosis (HH) has recently been identified. One mutation in this gene, termed HFE, has been found in all Australian HH patients. We previously identified a predominant HH ancestral haplotype covering 4.5Mb at 6p21.3, and showed that patients with two copies of this haplotype express a more severe form of the disorder. One key question to now be resolved is why haplotype related variation in phenotypic expression of HH is present if all patients tested have the same HFE mutation. A cosmid resource covering the 4.5Mb HH ancestral haplo type region was obtained. These cosmids provide the material for the completion of a transcript map of this region, and will assist the identification of candidate modifiers of HFE expression.

Chromosomes, Artificial, Yeast↗
PubMed1996

Evaluation of alpha interferon for the treatment of chronic hepatitis B infection in Christchurch.

AIM: To evaluate alpha interferon for the treatment of chronic replicative hepatitis B infection in Christchurch patients. METHODS: Ten patients were divided into two groups depending upon whether their average pretreatment ALT levels were greater than twice the upper limit of normal (group 1, 6 subjects) or less than twice the upper limit of normal (group 2, 4 subjects). Interferon alpha-2a (4.5 mega units) was administered three times a week for 24 weeks with the addition of a preceding priming course of prednisone in group 2. RESULTS: At 6 months post treatment only one patient in group 1 had seroconverted (HBeAg to anti-HBe), however, the remaining five patients seroconverted from 18-32 months after therapy. This response was associated with normalisation of the transaminases and in 5/6 subjects a fall in the HBV DNA levels. In group 2 one subject seroconverted by 6 months despite a shortened course of Interferon. A delayed seroconversion (18 months) was observed in one patient and another had a partial response with the development of anti-HBe but associated with persistence of HBeAg. The remaining patient has not responded. CONCLUSIONS: Interferon alpha-2a was effective in promoting a seroconversion HBeAg to anti-HBe in patients with chronic hepatitis B and transaminases elevated to twice the upper limit of normal, although in most cases this response was delayed. Larger studies will be required to determine the role of steroid priming in those with less active disease.

Adult↗
PubMed1996

A 4.5-megabase YAC contig and physical map over the hemochromatosis gene region.

We have constructed a yeast artificial chromosome (YAC) contig over the candidate hemochromatosis gene region. This contig comprises 16 YACs from the CEPH, Washington University, and ICI YAC libraries and covers 4.5 Mb at 6p21.3-6p22. The complete contig has been restriction mapped, enabling the precise relationship between the YACs to be determined and the mapping of a total of 12 STSs. Nine of these are highly polymorphic STSs that are closely linked to hemochromatosis; this series includes D6S265 and D6S1260, which comprise the most proximal and distal markers linked to HC. This is the first YAC contig that spans the hemochromatosis candidate region, and it provides valuable resource material for the cloning of this and other genes in the region distal to the MHC class I complex.

Base Sequence↗
PubMed1996

Haemochromatosis--a clinical update.

Haemochromatosis is now known to be a common genetic disorder, with a carrier rate of about 1 in 10 in populations of Northern European origin. With early diagnosis and treatment, life expectancy is normal, yet it remains underdiagnosed.

Biopsy↗
PubMed1995

Treatment of chronic hepatitis C with interferon alpha.

AIM: To evaluate the response to interferon alpha in patients with chronic hepatitis C in Christchurch. METHOD: Fifteen patients with chronic HCV were given interferon alpha 3 million units subcutaneously three times a week for up to 24 weeks. A complete and partial biochemical response was defined by relative changes in the serum alanine aminotransferase (ALT) during the treatment period. Detection of HCV RNA by the polymerase chain reaction was used to determine the virological response to treatment. RESULT: A complete or partial response was seen in nine of the 15 patients (60%). Histological improvement was demonstrated in all patients for whom paired liver biopsies were taken. Following treatment two of the five complete responders have shown a sustained biochemical response but only one has remained PCR negative, ie, a sustained virological responder. The other three, complete responders and all four partial responders relapsed. CONCLUSION: The response to treatment and relapse was comparable with other studies. It remains to be shown whether investigation of the viral titre and/or viral type will help to explain the high relapse rate in these patients with chronic HCV.

Adult↗
PubMed1995

Haplotype analysis in Australian hemochromatosis patients: evidence for a predominant ancestral haplotype exclusively associated with hemochromatosis.

Hemochromatosis (HC), an inherited disorder of iron metabolism, shows a very strong founder effect in Australia, with the majority of patients being of Celtic (Scots/Irish) origin. Australian HC patients thus provide an ideal group in which to examine HC-gene-region haplotypes, to analyze the extent of linkage disequilibrium and genetic heterogeneity in HC. We have analyzed chromosomes from 26 multiply affected HC pedigrees, and we were able to assign HC status unambiguously to 107 chromosomes--64 as affected and 43 as unaffected. The haplotypes examined comprise the following highly polymorphic markers: the serological marker HLA-A and the microsatellites D6S248, D6S265, HLA-F, and D6S105. All show highly significant allelic association with HC and no evidence of separation from the disease locus by recombination. Analysis identified a predominant ancestral haplotype comprising alleles 5-1-3-2-8 (marker order: D6S248-D6S265-HLA-A-HLA-F-D6S105), present in 21 (33%) of 64 affected chromosomes, and exclusively associated with HC (haplotype relative risk 903). No other common haplotype was significantly associated with HC. Haplotype analysis in Australian HC patients thus provides strong evidence for (a) the introduction of HC into this population on an ancestral haplotype, (b) a common mutation associated with HC in Australian patients, and (c) a candidate HC-gene region extending between and including D6S248 and D6S105.

Australia↗
PubMed1994

Investigation of subjects with abnormal iron studies: role of the hepatic iron index.

AIM: Genetic haemochromatosis is a common disorder resulting in increased iron deposition in the liver and other organs but can be difficult to diagnose. The aim of this study was to assess the diagnostic value of the conventional tests for iron overload (percentage saturation of transferrin, serum ferritin and grading of iron staining on liver biopsy) and compare these with the newer quantitative biochemical measurements of liver iron. METHOD: A retrospective analysis was made of 108 consecutive patients referred for quantitative liver iron measurements. Iron studies were obtained in 66 of the 108 subjects of whom 60 had abnormal screening tests defined as percent saturation of transferrin (> 60%) and/or ferritin > 350 micrograms/L for females and > 450 micrograms/L for males. Based on clinical features, biochemical data and treatment outcome these 60 subjects were classified as either genetic haemochromatosis, nongenetic haemochromatosis or indeterminate. One patient with treated genetic haemochromatosis was excluded from subsequent analysis. RESULTS: Although the serum ferritin (p < 0.002), percentage saturation of transferrin (p < 0.001), histological iron grade (p < 0.0001) were significantly higher in the genetic haemochromatosis than nongenetic haemochromatosis group there was considerable overlap. Similarly for the hepatic iron concentration (HIC) (p < 0.0001) overlap occurred. The hepatic iron index (HIC/age) gave the best separation with only three cases being misclassified. A correlation between the HII and histological iron index (visualised iron score corrected for age) in 15 subjects gave an r value of 0.72. CONCLUSION: Based on this study we feel that in addition to visual grading of iron in liver biopsies, the hepatic iron index is helpful in establishing a diagnosis of genetic haemochromatosis.

Adult↗
PubMed1993

The fate of ingested 14C-urea in the urea breath test for Helicobacter pylori infection.

The metabolic fate of the radioactive carbon in the 14C-urea breath test for Helicobacter pylori was investigated in 18 subjects. After ingestion of labelled urea, breath was sampled for 24 h, and urine was collected for 3 days. Subjects were designated high or low expirers on the basis of their breath counts, and this agreed well with H. pylori serologic analyses. When given 185 or 37 kBq of 14C-urea, 51% (SD = 16%, n = 11) of the label was recovered from the breath of high expirers, and 7% (SD = 3%, n = 7) from the breath of low expirers. The mean combined urinary and breath recovery for high expirers was 86% (SD = 7%), and for low expirers it was 97% (SD = 3%). It is concluded that the long-term retention of 14C from ingested 14C-urea is low. The results enable a more accurate estimation to be made of radiation exposure resulting from the 14C-urea breath test.

Breath Tests↗
PubMed1992

Viral hepatitis in the Christchurch community.

AIM: To determine the relative frequency of known causes of viral hepatitis in the Christchurch community. METHODS: Serum samples were collected at a private laboratory from patients aged 15-75 years who had an elevated transaminase of at least twice normal. RESULTS: One hundred and thirty-three subjects entered the study of whom 32 were positive for Epstein Barr virus, three for cytomegalovirus, nine for hepatitis A virus, and eight for hepatitis B virus. Paired convalescent samples were obtained from 64 of the remaining 81 subjects (17 lost or declined) and seven of these were positive for hepatitis C. Assuming a similar percentage in the lost/declined group this corrects to nine. CONCLUSION: The relative frequency of viral agents causing hepatitis was Epstein Barr virus 52%, cytomegalovirus 5%, hepatitis A virus 15%, hepatitis B virus 13% and hepatitis C virus 15%. Hepatitis C virus is a common cause of viral hepatitis in the Christchurch community.

Adolescent↗
PubMed1992

The prevalence of antibodies to hepatitis C virus in patients with chronic liver disease.

OBJECT: to determine the prevalence of antibodies to hepatitis C virus in selected groups of patients with chronic liver disease. METHODS: serum specimens were obtained from 39 patients with chronic liver function abnormalities of uncertain cause (group A), from 15 patients with autoimmune chronic active hepatitis (group B) and from 10 patients with chronic hepatitis B (group C). In an extension of the study, serum was collected from sexual partners of patients found to be HCV seropositive. A second generation ELISA assay (Abbott) was used to analyse the specimens. RESULTS: ten patients (26%) in group A were seropositive, one (7%) in group B and three (30%) in group C. Risk factors for infection included blood transfusion in three, intravenous drug use in six (including the only positive patient in group B) and both factors in another patient. Only one of the 10 sexual partners tested was positive but this subject was also an intravenous drug user. CONCLUSIONS: hepatitis C virus is a significant cause of chronic liver disease in Christchurch. Important risk factors include blood transfusion and intravenous drug use although sporadic cases occur. Transmission to sexual partners is uncommon. The second generation assay does not appear to give false positive results in autoimmune chronic active hepatitis.

Adult↗
PubMed1991

Pyogenic liver abscesses: a retrospective review of 24 cases.

OBJECTS: to review our experience of pyogenic liver abscess with attention to the value of ultrasound and computerised tomography, and the duration of antimicrobial therapy. METHOD: retrospective review of all pyogenic liver abscesses in Christchurch hospitals between 1972 and 1989. RESULTS: twenty-four cases were identified. The presentation of these cases was typical of those described in other series. Ultrasound scanning was positive in 69% of cases, and computerised tomography in 94%. Enteric organisms were isolated from blood or abscess cavities in all but two cases. Two patients died soon after admission and three were treated with antimicrobial therapy alone. The remainder underwent either a percutaneous or surgical drainage procedure, and received antimicrobial therapy. The antimicrobial therapy was clearly inappropriate in two patients. Eight patients (67%) with single abscesses received less than 10 days of antimicrobial therapy. Four patients (50%) with multiple abscesses received less than 18 days therapy. No patient relapsed. CONCLUSIONS: ultrasound is a convenient initial imaging technique, but may give false negative results. Computerised tomography should be done promptly if clinical suspicion of a liver abscess persists. Both surgical and percutaneous drainage techniques gave good results in combination with antimicrobial therapy. It is probably unnecessary to give prolonged courses of antimicrobial therapy following drainage of single liver abscess, provided there is rapid resolution. Multiple abscesses, or those which are not drained, may require longer courses of antimicrobial therapy.

Adolescent↗
PubMedDate not supplied

Two cases of Caroli's disease: diagnosis and management.

Caroli's disease is an uncommon congenital malformation involving the intrahepatic bile ducts. This paper reports two cases presenting with biliary tract infection. Diagnosis was established by non-invasive imaging and cholangiography. The infecting organisms were cultured from bile obtained by percutaneous aspiration and the results were used to direct antimicrobial therapy. The role of antibiotics and other management options in preventing recurrent infection is discussed.

Adult↗