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Dive into the research topics where John Crowe is active.

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Featured researches published by John Crowe.


Gastrointestinal Endoscopy | 1995

Endoscopic balloon sphincteroplasty (papillary dilation) for bile duct stones: efficacy, safety, and follow-up in 100 patients

Padraic Mac Mathuna; Peggy White; Eileen Clarke; R. Merriman; John Lennon; John Crowe

BACKGROUND Because sphincterotomy accounts for a major portion of the morbidity and mortality associated with ERCP, we have proposed endoscopic balloon papillary dilation or sphincteroplasty as an alternative. METHODS We report the outcome in a series of 100 patients in whom balloon sphincteroplasty was attempted for bile duct stones up to 20 mm in diameter, with a median follow-up of 16 months (range 6 to 30). RESULTS During one ERCP session using sphincteroplasty alone, the bile duct was cleared in 78%, mechanical lithotripsy being required in 10% for stones greater than 12 mm in diameter. Incomplete duct clearance was achieved in a further 4%, all of whom underwent repeat ERCP with successful duct clearance without recourse to sphincterotomy. Failure to clear the bile duct with sphincteroplasty in the remaining 18% was primarily related to large stone size ( > 15 mm). Sphincterotomy was required to clear the duct in 7%. Another 6% comprised elderly high-risk patients with multiple large stones greater than 15 mm who were treated by stent insertion plus ursodeoxycholic acid. No papillary hemorrhage was observed; uncomplicated pancreatitis occurred in 5%. During a median follow-up of 16 months, 2% had recurrent symptomatic bile duct stones considered to have been unrecognized following the initial ERCP: these were removed after repeat sphincteroplasty. No clinical evidence of papillary stenosis was observed during follow-up. CONCLUSIONS Endoscopic balloon papillary dilation or sphincteroplasty is a safe and effective alternative to sphincterotomy in the management of bile duct stones less than 12 mm; larger stones may require mechanical lithotripsy to facilitate duct clearance.


Gut | 2001

The natural course of hepatitis C virus infection after 22 years in a unique homogenous cohort: spontaneous viral clearance and chronic HCV infection

Sharon Barrett; J Goh; Barbara Coughlan; Eleanor Ryan; Stephen Stewart; A Cockram; J C O'Keane; John Crowe

BACKGROUND/AIMS The cohort of Irish women infected with hepatitis C virus (HCV) genotype 1b via contaminated anti-D immunoglobulin in 1977 represent a unique homogenous group to investigate the natural course of HCV infection. METHODS The clinical status of 87 polymerase chain reaction (PCR) positive and 68 PCR negative women was investigated at diagnosis (1994/95) and after 4–5 years of follow up (21/22 years after inoculation). Other features investigated included: histological status/progression, psychosocial impact of HCV infection, extrahepatic manifestations, and HLA class II associations. RESULTS The most common symptoms reported were fatigue and arthralgia. Furthermore, 77% of women fell within the clinical range for psychological distress. A history of icteric hepatitis was reported in 20.6% of PCR negative and 3.4% of PCR positive women after inoculation (p=0.002). The mean histological activity index/fibrosis scores of PCR positive and negative women were 4.1 (1.4)/1.1 (1.3) and 2.1 (1.5)/0.15 (0.36) at diagnosis and 4.1 (1.2)/1.0 (1.0) in 44 PCR positive women after five years of follow up. Cirrhosis or hepatocellular carcinoma was not observed. The DRB1*01 allele was present in 28.8% of PCR negative and 8.7% of PCR positive women (p=0.004). The prevalence rates of mixed cryoglobulinaemia, sicca complex, positive thyroid autoantibodies, antinuclear antibody, rheumatoid factor, and antimitochondrial antibody in PCR positive women were 12.7%, 7.6%, 13.9%, 5.1%, 3.8%, and 3.8%. CONCLUSIONS A benign course of HCV infection with lack of disease progression was observed in women with chronic HCV, 22 years after inoculation. Acute icteric hepatitis and the HLA DRB1*01 allele were associated with viral clearance. Despite this favourable outcome, high levels of psychological distress and poor quality of life were present.


Gut | 2005

The CCR5-Δ32 mutation: impact on disease outcome in individuals with hepatitis C infection from a single source

C Goulding; A Murphy; G MacDonald; Sharon Barrett; John Crowe; J. Hegarty; S McKiernan; Dermot Kelleher

Background and aims: Chemokines are small polypeptides, a major function of which is lymphocyte recruitment and trafficking. The aim of this study was to assess the involvement of inherited variations in CCR2, CCR5, and the ligand RANTES in determining disease outcome in hepatitis C virus (HCV) infected individuals. Methods: A total of 283 women, all exposed to HCV genotype 1b from a single donor, and including those who had spontaneously cleared the virus and those chronically infected, were genotyped for CCR2, CCR5, and RANTES polymorphisms. The frequencies of these polymorphisms were then compared with disease activity and severity. Results: CCR5, CCR2, and RANTES genotypes were compared with HCV polymerase chain reaction (PCR) status, alanine aminotransferase levels, and liver histology. There was no significant relationship between CCR2 or RANTES polymorphisms and disease outcome or severity. However, CCR5Δ32 heterozygotes were more likely to have spontaneous clearance of the virus than those without the mutation (42% PCR negative v 28.3% negative; p = 0.044, odds ratio 1.83 (95% confidence interval 1.1–3.6)). Among the subgroup of DRB1*03011 negative individuals, previously found to be associated with more severe inflammation, the difference in histological inflammatory score (CCR5WT/WT = 4.9 v CCR5Δ32/WT = 3.53; p = 0.043) was significant. Conclusion: Heterozygosity for CCR5Δ32 was shown to be significantly associated with spontaneous hepatitis C viral clearance and with significantly lower hepatic inflammatory scores in subgroups within this cohort. Both controls and the HCV population had similar heterozygosity frequencies.


Journal of Hepatology | 1999

Association of the HLA-DRB1*01 allele with spontaneous viral clearance in an Irish cohort infected with hepatitis C virus via contaminated anti-D immunoglobulin

Sharon Barrett; Eleanor Ryan; John Crowe

BACKGROUND/AIMS The hosts immune response may influence the course of hepatitis C virus (HCV) infection. The aim of this study was to examine the distribution of HLA Class II DRB1* alleles in a homogeneous cohort of individuals who were infected with HCV-contaminated anti-D immunoglobulin, and to compare frequencies of alleles in individuals with spontaneous viral clearance to those with chronic HCV infection. METHODS HLA DRB1* typing was performed on whole blood or serum from 157 females. Of these, 73 had spontaneously recovered from infection (persistently HCV RNA negative), while 84 had chronic HCV infection (persistently HCV RNA positive). A group of 5000 healthy bone marrow donors served as a control population. RESULTS No significant differences were observed between individuals with spontaneous viral clearance or chronic HCV infection for age, sex, alcohol consumption, source or duration of infection. The DRB1*01 allele was found significantly more frequently in individuals with viral clearance compared to those with chronic infection (27.4% vs. 7.1% p = 0.001, odds ratio OR = 4.9, pc = 0.01). No significant association was shown between severity of liver disease and DRB1* alleles. CONCLUSIONS DRB1*01 is associated with spontaneous viral clearance in an Irish cohort infected with HCV via contaminated anti-D immunoglobulin. HLA-DRB1* genes do not appear to influence severity of liver disease. These results suggest that host HLA-DRB1* alleles are important contributors to disease outcome.


The Lancet | 1984

RANITIDINE AND CIMETIDINE IN PREVENTION OF DUODENAL ULCER RELAPSE: A Double-blind, Randomised, Multicentre, Comparative Trial

K.R. Gough; K.D. Bardhan; John Crowe; M.G. Korman; F.I. Lee; Peter I. Reed; R.N. Smith

In a comparative trial of preventive medication for duodenal ulceration with 51 participating centres, 484 patients were recruited for a years maintenance treatment with the recommended bedtime dose of ranitidine (150 mg; n = 243) or cimetidine (400 mg; n = 241). These outpatients had recently healed duodenal ulcers, confirmed by endoscopy before and after healing, and ulcer relapse was monitored by endoscopy every 4 months. The distribution of factors likely to influence ulcer recurrence was similar in the two treatment groups. A life-table method of analysis showed that the ulcer relapse rate was consistently and significantly lower on ranitidine that on cimetidine (8% v 21%, p = 0.0018 at 4 months; 14% v 34%, p less than 0.0001 at 8 months; and 23% v 37%, p = 0.004 at 12 months). Crude relapse rate calculations, which underestimate the probability of ulcer recurrence, also confirmed the significant superiority of ranitidine 150 mg over cimetidine 400 mg nightly in preventing ulcer recurrence throughout the year.


Gut | 1994

Endoscopic sphincteroplasty: a novel and safe alternative to papillotomy in the management of bile duct stones.

P Mac Mathuna; P. White; E Clarke; John Lennon; John Crowe

Removal of bile duct stones during endoscopic retrograde cholangiopancreatography (ERCP) usually includes papillotomy. Papillotomy is associated with occasional complications and in addition, the longterm sequelae of papillotomy in young patients having laparoscopic cholecystectomy remain unclear. As an alternative to papillotomy, this study prospectively evaluated the efficacy and safety of endoscopic balloon sphincteroplasty to facilitate bile duct clearance. Of 32 patients with bile duct stones (diameter 3-30 mm) at ERCP, sphincteroplasty was considered inappropriate in four patients because of stone size (> 20 mm) necessitating papillotomy for bile duct clearance. Sphincteroplasty was performed in the remaining 28 patients to permit duct clearance by dormier basket, balloon or mechanical lithotripsy. The bile duct was cleared in 22 patients (79%) while additional measures including papillotomy or stent insertion were required in the remaining six patients (21%) because of stone size or technical difficulties. There was no associated papillary haemorrhage. Pancreatitis was seen in one patient (4%) but resolved within 24 hours. Our preliminary experience suggests that sphincteroplasty is a safe and effective sphincter preservation technique that significantly reduces the necessity for papillotomy in the management of bile duct stones.


Genetic Testing | 2001

Genetic hemochromatosis, a Celtic disease: is it now time for population screening?

Byrnes; Eleanor Ryan; Sharon Barrett; Kenny P; Mayne P; John Crowe

In populations of northern European ancestry, hereditary hemochromatosis (HH) is tightly linked to mutations within the hemochromatosis gene (HFE gene). Over 93% of Irish HH patients are homozygous for the HFE gene C282Y mutation, providing a reliable diagnostic marker of the disease in this population. However, the prevalence of the C282Y mutation and that of the second HFE gene mutation, H63D, have yet to be determined within the Irish population. The objective of this study was to identify the true prevalence of the genetic form of HH in the Irish population. DNA was extracted from 1002 randomly selected newborn screening cards and analyzed for the C282Y and H63D mutations within the HFE gene. Complete results were obtained from 800 cards. Mutations were identified in 364 (46%) neonates. Eight (1%) neonates were homozygous for C282Y and 8 (1%) were homozygous for H63D. One hundred and fifty-five (19%) neonates were C282Y heterozygous and 226 (28%) were H63D heterozygous. Of these, 33 (4%) carried one copy of both C282Y and H63D mutations, i.e., compound heterozygous. Allele frequencies for C282Y and H63D were 11% and 15%, respectively. The high C282Y allele frequency in the Irish population together with its close linkage to HH indicate that C282Y genotyping is the preferred screening strategy for this disease in Ireland.


European Journal of Gastroenterology & Hepatology | 2000

The detection of cytokeratins in lymph nodes of Duke's B colorectal cancer subjects predicts a poor outcome.

Gerard Clarke; Eleanor Ryan; O'Keane Jc; John Crowe; Padraic MacMathuna

Objectives The objectives of this study were to examine the frequency of lymph node micrometastases detected by keratin immunohistochemistry and their relationship with survival behaviour. Methods A total of 133 consecutive patients staged as Dukes B, who had curative resection for colorectal cancer (CRC), comprised the study population. Patients who had died of a non‐CRC‐related cause or who became lost to follow‐up were excluded, resulting in an amended population of 100. Study end‐points were defined as disease‐free survival of 5 years or CRC‐related death. Paraffin‐embedded lymph node sections were stained with a commercial cytokeratin antibody using a standard avidin‐biotin technique. Results One quarter of subjects had micrometastases. Fifty‐six per cent of subjects with positive lymph nodes had an adverse outcome, compared with 11% of subjects with negative nodes. A highly significant association was found between lymph node cytokeratin expression and mortality in both the univariate (log rank P = 0.0001) and multivariate (Cox proportional hazards P= 0.0123) analysis. Conclusions Lymph node micrometastases detected by this inexpensive and simple technique are significantly associated with mortality in Dukes B CRC. This technique may be used to select patients for adjuvant chemotherapy. Eur J Gastroenterol Hepatol 12:549‐552


European Journal of Gastroenterology & Hepatology | 2004

Clinical expression of haemochromatosis in Irish C282Y homozygotes identified through family screening.

F Gleeson; Eleanor Ryan; Sharon Barrett; John Crowe

Background In Ireland, the homozygote frequency of the C282Y mutation in the HFE gene is 1/83. The biochemical expression of this mutation is high in haemochromatosis (HH) individuals identified through family screening, but the clinical expression of the mutation in Irish HH subjects to date has not been investigated fully. Objectives To determine the clinical, biochemical and histological penetrance of the C282Y mutation in Irish C282Y homozygotes identified through family screening. Method Two hundred and nine C282Y homozygous individuals comprising of 172 first-degree relatives, 31 second-degree relatives and four unrelated individuals were identified following HFE mutation analysis of 167 families. The following variables were analysed: age at identification, gender, fasting transferrin saturation, fasting serum ferritin, liver enzymes, clinical symptomatology, liver histopathology and histochemical iron staining. Results An elevated transferrin saturation in combination with an elevated ferritin was present in 43.4% of males and 23.3% of females. Abnormal liver enzymes were found in 32.3% of males. Diabetes, a haemochromatosis-specific association, was noted in 2.8% of males. Of those individuals requiring liver histopathology evaluation, 38% had moderate-to-severe iron staining, and 42% had fibrosis; 2.8% of the biopsied cohort had cirrhosis. Thus, HH cirrhotics were identified in less than 1% of the screened population. Conclusion Although the homozygote frequency in Ireland is very high, the prevalence of advanced liver disease was less than 1% of the family members screened. Nevertheless, 42% of biopsied patients had histological evidence of iron overload-related architectural change and 2.8% had cirrhosis. This cohort of young people had previously unrecognized biochemical iron overload and histopathological change. This emphasizes the importance and value of both genetic and biochemical screening in first-degree relatives of identified homozygotes.


Gut | 2002

Underdiagnosis of hereditary haemochromatosis: lack of presentation or penetration?

Eleanor Ryan; V Byrnes; Barbara Coughlan; A-M Flanagan; Sharon Barrett; J C O'Keane; John Crowe

Background: The majority of hereditary haemochromatosis (HH) patients are homozygous for the C282Y mutation in the HFE gene. We have demonstrated a homozygote frequency of 1 in 83 for the C282Y mutation in a retrospective analysis of Irish neonates. However, a fully developed phenotype is not observed at the same frequency clinically, suggesting that a large proportion of Irish HH patients may remain undiagnosed. Aims: To determine whether underdiagnosis of HH results from the non-specific nature of early symptoms or incomplete penetrance of the C282Y mutation. Methods: Seventy nine C282Y homozygous individuals identified from family screening for HH and 30 HH probands were investigated. Non-specific symptoms (fatigue, arthropathy, and impotence) and their association with iron indices (transferrin saturation and serum ferritin) and hepatic iron deposition were analysed. Results: We found that 78% of men (mean age 42 years) and 36% of women (mean age 39 years) who were identified as C282Y homozygotes following family screening had iron overload, as defined by a transferrin saturation ≥52% combined with a serum ferritin ≥300 μg/l for men and ≥200 μg/l for women. The frequency of reports of non-specific symptoms in those individuals with iron overload was not significantly different from those who did not have iron overload. Conclusions: Our findings indicate that underdiagnosis of HH may be due to the non-specific nature of early symptoms and less frequently to the incomplete penetrance of the C282Y mutation.

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Eleanor Ryan

Mater Misericordiae Hospital

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Sharon Barrett

Mater Misericordiae Hospital

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Barbara Coughlan

Mater Misericordiae Hospital

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John Lennon

Mater Misericordiae University Hospital

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John Ryan

University College Dublin

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Padraic MacMathuna

Mater Misericordiae University Hospital

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John Sheehan

Mater Misericordiae University Hospital

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Alan Carr

University College Dublin

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Valerie Byrnes

Mater Misericordiae Hospital

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Roger Williams

Laboratory of Molecular Biology

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