MicroRNA expression is associated with human papillomavirus status and prognosis in mucosal head and neck squamous cell carcinomas

OBJECTIVES

The major cause of mucosal squamous cell carcinomas of the head and neck (HNSCCs) has been attributed to human papillomavirus (HPV) infection. Here we investigate if microRNA expression in HNSCC can be used as a prognostic tool with or without HPV status.

MATERIALS AND METHODS

We performed a discovery miRNA microarray (miRBase v.21) profiling of 52 tonsillar SCCs with TaqMan real-time PCR validation of 228 HNSCCs. Patients had a histologically confirmed primary SCC of the oropharynx, oral cavity, hypopharynx or larynx. Logistic regression models were used to estimate the magnitude of the effect of association with clinical factors and miRNAs associated with HPV status. For recurrence and survival analysis, we used unadjusted and multivariable adjusted Cox proportional hazard regression models.

RESULTS

Seventeen miRNAs were significantly associated with better prognosis in the discovery phase and were validated in the extended dataset. The best fitting model (AUC = 0.92) for HPV status included age, smoking, and miRNAs: miR-15b, miR-20b, miR-29a, miR-29c, miR-142, miR-146a and miR-205. Using Cox regression model for recurrence, miR-29a was associated with 49% increased risk of recurrence while miR-30e and miR-342 were associated with decreased risk of recurrence with HRs 0.92 (95% CI 0.85-0.99) and 0.84 (95% CI 0.73-0.98), respectively. Our best fitting model for survival included age, gender, alcohol consumption, N stage, recurrence, HPV status, together with miRNAs-20b, 29a, and 342.

CONCLUSION

miRNAs show potential to serve as usual biomarkers to predict the clinical course of patients with mucosal HNSCC.

Incidence and mortality for cutaneous squamous cell carcinoma: comparison across three continents

BACKGROUND

Population-based incidence and mortality studies of cutaneous squamous cell carcinoma (SCC) have been few owing to the commonness of the disease, and rare deaths making accurate mortality statistics difficult.

OBJECTIVES

Our aim was to summarize SCC incidence and mortality in populations across three continents, exemplified by Australia, the United States (US) and Germany.

METHODS

We estimated age-specific and age-standardized (Australian Standard 2001 Population) incidence and mortality rates per 100 000 person-years.

RESULTS

Squamous cell carcinoma incidence is plateauing or falling in Australia, stable in the United States (2013-2015) and rising in Germany (2007-2015). Current incidence estimates in men and women are 341 and 209, 497 and 296, and 54 and 26, respectively, for the three countries. Incidence increases strongly with age in all countries. Mortality of non-melanoma skin cancer appears to be increasing in Germany and stable in Australia (unavailable for the US population).

CONCLUSIONS

Squamous cell carcinoma is an important health issue, particularly among older men, with incidence exceeding most other cancers. More precise and uniform population-based studies of incidence and mortality are needed to better quantify the impact of SCC on healthcare systems worldwide and to gauge the effect of new treatments such as anti-PD1 therapy on mortality.

Does polygenic risk influence associations between sun exposure and melanoma? A prospective cohort analysis

BACKGROUND

Melanoma develops as the result of complex interactions between sun exposure and genetic factors. However, data on these interactions from prospective studies are scant.

OBJECTIVES

To quantify the association between ambient and personal ultraviolet exposure and incident melanoma in a large population-based prospective study of men and women residing in a setting of high ambient ultraviolet radiation, and to examine potential gene-environment interactions.

METHODS

Data were obtained from the QSkin Sun and Health Study, a prospective cohort study of men and women aged 40-69 years, randomly sampled from the Queensland population in 2011. Participants were genotyped and assessed for ultraviolet exposure.

RESULTS

Among participants with genetic data (n = 15 373), 420 (2·7%) developed cutaneous melanoma (173 invasive, 247 in situ) during a median follow-up time of 4·4 years. Country of birth, age at migration, having > 50 sunburns in childhood or adolescence, and a history of keratinocyte cancer or actinic lesions were significantly associated with melanoma risk.

CONCLUSIONS

An interaction with polygenic risk was suggested: among people at low polygenic risk, markers of cumulative sun exposure (as measured by actinic damage) were associated with melanoma. In contrast, among people at high polygenic risk, markers of high-level early-life ambient exposure (as measured by place of birth) were associated with melanoma (hazard ratio for born in Australia vs. overseas 3·16, 95% confidence interval 1·39-7·22). These findings suggest interactions between genotype and environment that are consistent with divergent pathways for melanoma development. What's already known about this topic? The relationship between sun exposure and melanoma is complex, and exposure effects are highly modified by host factors and behaviours. The role of genotype on the relationship between ultraviolet radiation exposure and melanoma risk is poorly understood. What does this study add? We found that country of birth, age at migration, sunburns in childhood or adolescence, and history of keratinocyte cancer or actinic lesions were significantly associated with melanoma risk, while other measures of continuous or more intermittent patterns of sun exposure were not. We found evidence for gene-environment interactions that are consistent with divergent pathways for melanoma development. Linked Comment: Cust. Br J Dermatol 2020; 183:205-206. Plain language summary available online.

Hysterectomy and incidence of depressive symptoms in midlife women: the Australian Longitudinal Study on Women's Health

AIMS

There is limited longitudinal research that has looked at the longer term incidence of depressive symptoms, comparing women with a hysterectomy to women without a hysterectomy. We aimed to investigate the association between hysterectomy status and the 12-year incidence of depressive symptoms in a mid-aged cohort of Australian women, and whether these relationships were modified by use of exogenous hormones.

METHODS

We used generalised estimating equation models for binary outcome data to assess the associations of the incidence of depressive symptoms (measured by the 10-item Centre for Epidemiologic Studies Depression Scale) across five surveys over a 12-year period, in women with a hysterectomy with ovarian conservation, or a hysterectomy with bilateral oophorectomy compared with women without a hysterectomy. We further stratified women with hysterectomy by their current use of menopausal hormone therapy (MHT). Women who reported prior treatment for depression were excluded from the analysis.

RESULTS

Compared with women without a hysterectomy (n = 4002), both women with a hysterectomy with ovarian conservation (n = 884) and women with a hysterectomy and bilateral oophorectomy (n = 450) had a higher risk of depressive symptoms (relative risk (RR) 1.20; 95% confidence interval (CI) 1.06-1.36 and RR 1.44; 95% CI 1.22-1.68, respectively). There were differences in the strength of the risk for women with a hysterectomy with ovarian conservation, compared with those without, when we stratified by current MHT use. Compared with women without a hysterectomy who did not use MHT, women with a hysterectomy with ovarian conservation who were also MHT users had a higher risk of depressive symptoms (RR 1.57; 95% CI 1.31-1.88) than women with a hysterectomy with ovarian conservation but did not use MHT (RR 1.17; 95% CI 1.02-1.35). For women with a hysterectomy and bilateral oophorectomy, MHT use did not attenuate the risk. We could not rule out, however, that the higher risk seen among MHT users may be due to confounding by indication, i.e. MHT was prescribed to treat depressive symptoms, but their depressive symptoms persisted.

CONCLUSIONS

Women with a hysterectomy (with and without bilateral oophorectomy) have a higher risk of new incidence of depressive symptoms in the longer term that was not explained by lifestyle or socio-economic factors.

Increasing thyroid cancer incidence in Queensland, Australia 1982-2008 - true increase or overdiagnosis?

BACKGROUND

Thyroid cancer incidence has been increasing worldwide. Some suggest greater ascertainment of indolent tumours is the only driver, but others suggest there has been a true increase. Increases in Australia appear to have been among the largest in the world, so we investigated incidence trends in the Australian state of Queensland to help understand reasons for the rise.

METHODS

Thyroid cancers diagnoses in Queensland 1982-2008 were ascertained from the Queensland Cancer Registry. We calculated age-standardized incidence rates (ASR) and used Poisson regression to estimate annual percentage change (APC) in thyroid cancer incidence by socio-demographic and tumour-related factors.

RESULTS

Thyroid cancer ASR in Queensland increased from 2·2 to 10·6/100 000 between 1982 and 2008 equating to an APC of 5·5% [95% confidence interval (CI) 4·7-6·4] in men and 6·1% (95% CI 5·5-6·6) in women. The rise was evident, and did not significantly differ, across socio-economic and remoteness-of-residence categories. The largest increase seen was in the papillary subtype in women (APC 7·9%, 95% CI 7·3-8·5). Incidence of localized and more advanced-stage cancers rose over time although the increase was greater for early-stage cancers.

CONCLUSION

There has been a marked increase in thyroid cancer incidence in Queensland. The increase is evident in men and women across all adult age groups, socio-economic strata and remoteness-of-residence categories as well as in localized and more advanced-stage cancers. Our results suggest 'overdiagnosis' may not entirely explain rising incidence. Contemporary aetiological data and individual-level information about diagnostic circumstances are required to further understand reasons for rising thyroid cancer incidence.

Prevalence and determinants of frequent gastroesophageal reflux symptoms in the Australian community

Frequent gastroesophageal reflux (GER) causes chronic inflammation and damages esophageal mucosa, which can lead to Barrett's esophagus. It has also been consistently found to be a strong risk factor for esophageal adenocarcinoma. The prevalence of GER appears to vary; however, population-based Australian studies investigating the symptoms are limited. This study aimed to estimate the population prevalence and identify the determinants of frequent GER symptoms in the Australian population. Self-reported information on the frequency of reflux symptoms were collected from 1,580 adults from a population register. We estimated age- and sex-standardized prevalence of occasional (<weekly) and frequent (≥weekly) GER symptoms in the Australian population. We also estimated adjusted prevalence ratios (PR) for GER symptoms associated with demographic and lifestyle characteristics. The standardized prevalences of GER symptoms were 10.4% and 38.3% for frequent and occasional symptoms, respectively. Compared with participants with body mass index <25, those with body mass index ≥35 had almost 90% higher prevalence of frequent GER symptoms (PR 1.89; 95% confidence interval [CI] 1.13-3.16). Similarly, the prevalence of frequent GER symptoms was significantly higher among regular users of aspirin or other non-steroidal anti-inflammatory drugs than never users (PR 1.71; 95%CI 1.08-3.16) and regular consumers of medium to well-done barbecued meat (PR 1.75; 95%CI 1.10-2.80) or fried food (PR 2.69; 95%CI 1.66-4.35). The prevalence of frequent GER symptoms was significantly lowered with regular physical activity (PR 0.46; 95%CI 0.32-0.66) and Helicobacter pylori infection (PR 0.53; 95%CI 0.35-0.80). We found no evidence that frequent GER symptoms were associated with smoking, alcohol, spicy food, or coffee consumption. Our results confirm that GER symptoms are common and that frequent GER symptoms are associated with a range of modifiable lifestyle factors.

The use of nonsteroidal anti-inflammatory drugs and the risk of Barrett's oesophagus

BACKGROUND

Epidemiological studies have consistently reported inverse associations between nonsteroidal anti-inflammatory drugs (NSAIDs) and oesophageal adenocarcinoma, but few have investigated associations with the precursor lesion, Barrett's oesophagus.

AIM

To investigate the relationship between NSAID use and risk of Barrett's oesophagus.

METHODS

We conducted a large population-based case-control study that collected information on patterns of intake for aspirin and non-aspirin NSAIDs during the past 5 years and other exposures from 285 patients with nondysplastic Barrett's oesophagus, 108 patients with dysplastic Barrett's oesophagus, and two separate control groups: 313 endoscopy patients with acute inflammatory changes ('inflammation controls') and 644 population controls. We calculated odds ratios (ORs) and 95% CIs using unconditional logistic regression.

RESULTS

Use of aspirin was not associated with nondysplastic Barrett's oesophagus when compared with population (OR=1.01, 95% CI 0.71-1.43) or inflammation controls (OR=1.16, 95% CI 0.80-1.68). Whereas we observed significant risk reductions for use of non-aspirin NSAIDs when nondysplastic Barrett's oesophagus cases were compared with population controls (OR=0.69, 95% CI 0.49-0.97), the effect was weaker and nonsignificant when cases were compared with inflammation controls (OR=0.82, 95% CI 0.57-1.18), and no dose-response effects were present in either analysis. We found no evidence that aspirin or non-aspirin NSAID use conferred risk reductions for dysplastic Barrett's oesophagus, regardless of the control series. We excluded effect modification by known risk factors as an explanation for these null findings.

CONCLUSIONS

We found little support for an inverse association between use of NSAIDs and Barrett's oesophagus. The question of whether or not these medications prevent the onset of Barrett's oesophagus remains open.

Gastro-oesophageal reflux symptoms and the risks of oesophageal cancer: are the effects modified by smoking, NSAIDs or acid suppressants?

OBJECTIVE

To measure the extent to which risks of oesophageal cancers associated with gastro-oesophageal reflux (GOR) are modified by common factors including smoking, non-steroidal anti-inflammatory drugs (NSAIDs) and acid suppressant medications.

DESIGN AND SETTING

Population-based case-control study.

PARTICIPANTS

Cases were patients with oesophageal (OAC; n = 365) or gastro-oesophageal junction (GOJAC; n = 426) adenocarcinomas, or squamous cell carcinomas (OSCC; n = 303). Controls were sampled from a population register (n = 1580).

MAIN OUTCOME MEASURE

Odds ratio and 95% confidence interval.

RESULTS

Frequent (at least weekly) symptoms of GOR were associated with significant 6.4-fold, 4.6-fold and 2.2-fold increased risks of OAC, GOJAC and OSCC, respectively. Under models examining effects of combined exposure, patients with frequent GOR symptoms who were also heavy smokers had markedly higher OAC risks (OR = 12.3, 95% CI 6.3 to 24.0) than those with frequent GOR who did not smoke (OR = 6.8, 95% CI 3.6 to 12.9). Similar patterns were observed for GOJAC and OSCC. Among people with frequent GOR symptoms, regular use of aspirin/NSAIDs was associated with almost two-thirds lower OAC risks (OR = 4.8, 95% CI 2.5 to 9.2) than non-users (13.9, 95% CI 6.5 to 30.0). In contrast, among those with frequent GOR symptoms, users of acid suppressants had similar OAC risks (OR 7.8, 95% CI 5.2 to 11.8) to non-users (OR 5.3, 95% CI 3.2 to 9.0).

CONCLUSIONS

People experiencing frequent GOR symptoms have markedly increased risks of OAC and GOJAC, and this effect may be greater amongst smokers. Use of aspirin and NSAIDs, but not acid suppressants, significantly reduced the risks of oesophageal cancers associated with GOR.

Leptin and the risk of Barrett's oesophagus

BACKGROUND

Obesity is associated with increased risks of Barrett's oesophagus and oesophageal adenocarcinoma. Alterations in serum leptin and adiponectin, obesity-related cytokines, have been linked with several cancers and have been postulated as potential mediators of obesity-related carcinogenesis; however, the relationship with Barrett's oesophagus remains unexplored.

METHODS

Serum leptin and adiponectin concentrations were measured on two subsets of participants within a case-control study conducted in Brisbane, Australia. Cases were people aged 18-79 years with histologically confirmed Barrett's oesophagus newly diagnosed between 2003 and 2006. Population controls, frequency matched by age and sex to cases, were randomly selected from the electoral roll. Phenotype and medical history data were collected through structured, self-completed questionnaires. Odds ratios (OR) and 95% CI were calculated using multivariable logistic regression analysis.

RESULTS

In the pilot analysis (51 cases, 67 controls) risks of Barrett's oesophagus were highest among those in the highest quartile of serum leptin (OR 4.6, 95% CI 0.6 to 33.4). No association was seen with adiponectin. In the leptin validation study (306 cases, 309 controls), there was a significant threefold increased risk of Barrett's oesophagus among men in the highest quartile of serum leptin (OR 3.3, 95% CI 1.7 to 6.6) and this persisted after further adjustment for symptoms of gastro-oesophageal reflux (OR 2.4, 95% CI 1.1 to 5.2). In contrast, the risk of Barrett's oesophagus among women decreased with increasing serum leptin concentrations.

CONCLUSIONS

High serum leptin is associated with an increased risk of Barrett's oesophagus among men but not women. This association is not explained simply by higher body mass or gastro-oesophageal reflux among cases. The mechanism remains to be determined.

Combined effects of obesity, acid reflux and smoking on the risk of adenocarcinomas of the oesophagus

OBJECTIVE

To measure the relative risks of adenocarcinomas of the oesophagus and gastro-oesophageal junction associated with measures of obesity, and their interactions with age, sex, gastro-oesophageal reflux symptoms and smoking.

DESIGN AND SETTING

Population-based case-control study in Australia.

PATIENTS

Patients with adenocarcinomas of the oesophagus (n = 367) or gastro-oesophageal junction (n = 426) were compared with control participants (n = 1580) sampled from a population register.

MAIN OUTCOME MEASURE

Relative risk of adenocarcinoma of the oesophagus or gastro-oesophageal junction.

RESULTS

Risks of oesophageal adenocarcinoma increased monotonically with body mass index (BMI) (p(trend) <0.001). Highest risks were seen for BMI >or=40 kg/m2 (odds ratio (OR) = 6.1, 95% CI 2.7 to 13.6) compared with "healthy" BMI (18.5-24.9 kg/m2). Adjustment for gastro-oesophageal reflux and other factors modestly attenuated risks. Risks associated with obesity were substantially higher among men (OR = 2.6, 95% CI 1.8 to 3.9) than women (OR = 1.4, 95% CI 0.5 to 3.5), and among those aged <50 years (OR = 7.5, 95% CI 1.7 to 33.0) than those aged >or=50 years (OR = 2.2, 95% CI 1.5 to 3.1). Obese people with frequent symptoms of gastro-oesophageal reflux had significantly higher risks (OR = 16.5, 95% CI 8.9 to 30.6) than people with obesity but no reflux (OR = 2.2, 95% CI 1.1 to 4.3) or reflux but no obesity (OR = 5.6, 95% 2.8 to 11.3), consistent with a synergistic interaction between these factors. Similar associations, but of smaller magnitude, were seen for gastro-oesophageal junction adenocarcinomas.

CONCLUSIONS

Obesity increases the risk of oesophageal adenocarcinoma independently of other factors, particularly among men. From a clinical perspective, these data suggest that patients with obesity and frequent symptoms of gastro-oesophageal reflux are at especially increased risk of adenocarcinoma.

Aspirin and lung cancer risk in a cohort study of women: dosage, duration and latency

Aspirin may reduce the risk of cancer at some sites but its effect at the lung is unclear. We prospectively examined associations between aspirin use and risk of lung cancer in 109,348 women in the Nurses' Health study from 1980 to 2004. During this time, 1,360 lung cancers were documented in participants 36-82 years of age. Aspirin use and smoking were assessed every 2 years. Risk of lung cancer was a non-significant 16% lower for regular aspirin users of one or two tablets per week and a significant 55% higher for users of 15 or more tablets per week compared with women who never regularly used aspirin. Results were similar when limited to never smokers. For both the low and high quantity aspirin users, risk of lung cancer did not decline or increase with longer durations of use, and associations attenuated as the latency period between aspirin assessment and lung cancer diagnosis was lengthened. Our findings, together with those from previous clinical trials and prospective studies, do not provide consistent evidence that aspirin influences the development of lung cancer and further investigation is required with adjustment for smoking.

TNFalpha and IL10 SNPs act together to predict disease behaviour in Crohn's disease

BACKGROUND

The cytokines tumour necrosis factor (TNF)alpha and interleukin (IL)10 have been implicated in the pathogenesis of Crohn's disease (CD), with increased concentrations reported in patients with active disease. However, limited data exist on their effects on disease phenotype in the same population. Certain single nucleotide polymorphisms (SNPs) within the promoter region of the IL10 (-1082G/A, -592C/A) and TNFalpha (-308G/A, -857C/T) genes have been associated with altered levels of circulating IL10 and TNFalpha.

METHODS

We conducted an Australian based case-control study (304 CD patients; 231 healthy controls) of these four SNPs. Further investigation of two SNPs was conducted using a logistic regression analysis.

RESULTS

We identified a possible association of both IL10 SNPs and TNFalpha-857 with CD. Further investigation of a relationship with disease severity showed a significant association of higher producing IL10-1082G and TNFalpha-857C alleles with stricturing behaviour, which was strongest when these alleles were combined and persisted after multivariate analysis (p = 0.007; odds ratio (OR) 2.37, 95% CI 1.26 to 4.43). In addition, the TNFalpha-857CC genotype was independently associated with familial CD (p = 0.03; OR 3.12; 95% CI 1.15 to 8.46).

CONCLUSION

These two SNPs may help to predict disease behaviour in CD patients, which may be clinically useful in shaping treatment of the disease at an earlier stage.

Characterization of tumour-infiltrating lymphocytes and apoptosis in colitis-associated neoplasia: comparison with sporadic colorectal cancer

The development of colorectal cancer is a major complication for patients with chronic idiopathic colitis. Colitis-associated tumours tend to occur at a younger age and be more aggressive than sporadic colorectal cancers. While we have previously associated the presence of tumour-infiltrating lymphocytes (TILs) and increased apoptosis in sporadic colorectal cancer with high-level microsatellite instability and improved prognosis, little is known of the relationship between these variables in colitis-associated colorectal cancer. The aim of this study was to correlate TILs and tumour cell apoptosis in colitis-associated neoplasms stratified according to microsatellite instability. Twenty tumour and 11 dysplastic samples resected from 21 patients with long-standing colitis were analysed for microsatellite instability at 10 microsatellite markers. TIL distribution (CD3, CD8) and function (granzyme B) were quantified by immunohistochemistry. Neoplastic cell apoptosis was assessed using the M30 CytoDEATH antibody. These findings were compared with 40 microsatellite stable (MSS) sporadic colorectal cancers previously evaluated for TILs and neoplastic apoptosis. Low-level microsatellite instability was found in 1/20 colitis-associated tumours. All other colitis-associated lesions were designated MSS. CD3(+) and CD8(+) TIL counts were significantly higher in colitis-associated lesions compared with MSS sporadic colorectal cancer (p < 0.0001, p = 0.001 respectively). Despite their higher TIL density, colitis-associated tumours were more likely to present late (Dukes' stage C or D) (p = 0.02). Functionally, colitis-associated TILs demonstrated significantly less granzyme B expression compared to sporadic cancers (p = 0.002). The level of tumour cell apoptosis was similar between the two groups (sporadic, 1.53%; colitis cancers, 1.45%). In conclusion, MSS colitis-associated tumours have a higher prevalence of CD3(+)/CD8(+) TILs but no associated increase in tumour cell killing by apoptosis. Unlike cytotoxic T cells in sporadic colorectal cancer, TILs do not appear to enhance the prognosis of colitis-associated colorectal cancer. This may be related to an impairment of granzyme B expression within these lesions.

Ratio of male to female births in the offspring of BRCA1 and BRCA2 carriers

A recent report based on 68 families, including 17 with mutations in BRCA1, suggested that there was an excess of female offspring born to BRCA1 mutation carriers. We have examined the gender ratio among offspring of 511 mutation carriers from 116 BRCA1 families, 77 and 39 from Australia and the United States, respectively. We found no evidence for a significant deviation from the expected proportion of female offspring in the Australian pedigrees, but there was an excess of female offspring in pedigrees from the USA. Ascertainment bias probably explains this bias, rather than a link with X-chromosome inactivation as previously suggested, because the families from the USA were ascertained for the purposes of linkage studies whereas those from Australia were ascertained through Familial Cancer Clinics to which they had been referred for clinical genetic counseling and mutation testing.

CCR5-Delta32 mutation is strongly associated with primary sclerosing cholangitis

CCR5 plays a key role in the distribution of CD45RO+ T cells and contributes to generation of a T helper 1 immune response. CCR5-Delta32 is a 32-bp deletion associated with significant reduction in cell surface expression of the receptor. We investigated the role of CCR5-Delta32 on susceptibility to ulcerative colitis (UC), Crohn's disease (CD) and primary sclerosing cholangitis (PSC). Genotype and allelic association analyses were performed in 162 patients with UC, 131 with CD, 71 with PSC and 419 matched controls. There was a significant difference in CCR5 genotype (OR 2.27, P=0.003) between patients with sclerosing cholangitis and controls. Similarly, CCR5-Delta32 allele frequency was significantly higher in sclerosing cholangitis (17.6%) compared to controls (9.9%, OR 2.47, P=0.007) and inflammatory bowel disease patients without sclerosing cholangitis (11.3%, OR 1.9, P=0.027). There were no significant differences in CCR5 genotype or allele frequency between those with either UC or CD and controls. Genotypes with the CCR5-Delta32 variant were increased in patients with severe liver disease defined by portal hypertension and/or transplantation (45%) compared to those with mild liver disease (21%, OR 3.17, P=0.03). The CCR5-Delta32 mutation may influence disease susceptibility and severity in patients with PSC.

Epidemiology of appendicectomy in primary sclerosing cholangitis and ulcerative colitis: its influence on the clinical behaviour of these diseases

BACKGROUND AND AIMS

Appendicectomy and smoking are environmental factors that are known to influence ulcerative colitis (UC). The phenotype of UC is different in patients with coexistent primary sclerosing cholangitis (PSC). This study investigates the interaction of appendicectomy and PSC on the epidemiology and clinical behaviour of colitis.

METHODS

Patients were from the Brisbane IBD Research Group database. Controls were from the Australian twin registry. Seventy eight PSC-inflammatory bowel disease (PSC-IBD) patients, 12 pure PSC, and 294 UC patients were matched with 1466 controls by sex and birth cohort that comprised randomly selected twins from each twin pair. The effects of appendicectomy, smoking, or PSC on the onset of disease, disease extent, disease severity (as identified by immunosuppression-colectomy or liver transplant), and disease related complications (high grade dysplasia, colorectal cancer, or cholangiocarcinoma) were investigated using univariate and multiple logistic regression analyses.

RESULTS

PSC-IBD patients had a more extensive colitis than UC patients (p<0.0001) but required less immunosuppression (p = 0.007), which was independent of disease extent. They were more likely to have high grade dysplasia or colorectal cancer (p = 0.029) than UC patients. Appendicectomy rates in the PSC groups were not different from the control groups (p = 0.72, 0.76), which was in sharp contrast with UC where the rate was four times less (p = 0.0001). Prior appendicectomy appeared to be associated with an approximate five year delay in the onset of intestinal (PSC-IBD or UC) or hepatic (PSC) disease, which was independent of smoking. Appendicectomy did not independently alter the extent or severity of disease in PSC. In contrast, prior appendicectomy in UC was associated with more extensive disease but with a lesser requirement for immunosuppression or colectomy for the treatment of colitis (p = 0.004). There were trends for high grade dysplasia or colorectal cancer with appendicectomy in both PSC-IBD and UC. Although these trends were not statistically significant, colorectal cancer appeared more frequent with appendicectomy in a meta-analysis of the available UC data from this and another Australian study.

CONCLUSIONS

In contradistinction to UC, appendicectomy did not significantly influence the prevalence of the PSC groups, or the extent of colitis in PSC-IBD, but as with UC, did appear to delay their onset. The extensive milder colitis, which is characteristic of PSC-IBD, relates to other poorly understood factors. Further prospective studies are required to determine any influence of appendicectomy on the extent of colitis in IBD and an associated dysplasia or colorectal cancer.

Protective role of appendicectomy on onset and severity of ulcerative colitis and Crohn's disease

BACKGROUND AND AIMS

Recent studies on appendicectomy rates in ulcerative colitis and Crohn's disease have generally not addressed the effect of appendicectomy on disease characteristics. The aims of this study were to compare appendicectomy rates in Australian inflammatory bowel disease patients and matched controls, and to evaluate the effect of prior appendicectomy on disease characteristics.

METHODS

Patients were ascertained from the Brisbane Inflammatory Bowel Disease database. Controls matched for age and sex were randomly selected from the Australian Twin Registry. Disease characteristics included age at diagnosis, disease site, need for immunosuppression, and intestinal resection.

RESULTS

The study confirmed the significant negative association between appendicectomy and ulcerative colitis (odds ratio (OR) 0.23, 95% confidence interval (CI) 0.14-0.38; p<0.0001) and found a similar result for Crohn's disease once the bias of appendicectomy at diagnosis was addressed (OR 0.34, 95% CI 0.23-0.51; p<0.0001). Prior appendicectomy delayed age of presentation for both diseases and was statistically significant for Crohn's disease (p=0.02). In ulcerative colitis, patients with prior appendicectomy had clinically milder disease with reduced requirement for immunosuppression (OR 0.15, 95% CI 0.02-1.15; p=0.04) and proctocolectomy (p=0.02).

CONCLUSIONS

Compared with patients without prior appendicectomy, appendicectomy before diagnosis delays disease onset in ulcerative colitis and Crohn's disease and gives rise to a milder disease phenotype in ulcerative colitis.

Winter intervention against Aedes aegypti (Diptera: Culicidae) larvae in subterranean habitats slows surface recolonization in summer

At semiarid Charters Towers, north Queensland, Australia, the importance of Aedes aegypti (L.) in wells was assessed in relation to the colonization of surface habitats during the wet season. From April to July 1999, 10 wells (five positive for Ae. aegypti) were monitored to assess their status and larvae population numbers therein. All surface containers located within a 100 m radius of each well were removed, treated with s-methoprene or sealed to prevent the utilization of these containers by mosquitoes. These inner cores were surrounded by outer zones for a further 100 m in which surface containers were left untreated but all subterranean habitats were treated. Ovitraps were monitored monthly in the inner cores for 36 wk from August 1999 to April 2000 and differences in the proportions of ovitraps positive for Ae. aegypti and Ochlerotatus notoscriptus (Skuse) were analyzed by logistic regression. Analysis of the proportions of ovitraps positive for Ae. aegypti near positive wells indicated significantly greater colonization from November to March (the wet season), compared with those situated near Ae. aegypti negative wells. As Oc. notoscriptus were not produced from subterranean sites, comparisons of the proportions of ovitraps positive for Oc. notoscriptus in positive and negative inner cores provided an indication of the relative productivity of the uncontrolled surface containers in the outer zones. Differences in the utililization of ovitraps by Oc. notoscriptus among positive and negative cores were observed during only one month (March), when oviposition was greater in ovitraps in the negative cores, compared with the positive cores. Best subsets linear regression analysis of the proportion of ovitraps positive forAe. aegypti against meteorological variables (rainfall, mean wind speed, mean relative humidity, mean minimum, and maximum temperature) during the week of ovitrapping indicated that minimum temperature and wind speed accounted for 63.4% of the variability. This study confirms that for semiarid towns such as Charters Towers, the practice of treating a relatively small number of key subterranean habitats during winter will significantly affect Ae. aegypti recolonization of surface container habitats during summer, the period of greatest risk for dengue.

Proliferation, apoptosis, and survival in high-level microsatellite instability sporadic colorectal cancer

Sporadic colorectal cancer (CRC) characterized by high-level DNA microsatellite instability (MSI-H) has a favorable prognosis. The reason for this MSI-H survival advantage is not known. The aim of this study was to correlate proliferation, apoptosis, and prognosis in CRC stratified by MSI status. The proliferative index (PI) was measured by immunohistochemical staining with the Ki-67 antibody in a selected series of 100 sporadic colorectal cancers classified according to the level of MSI as 31 MSI-H, 29 MSI-Low (MSI-L), and 40 microsatellite stable (MSS). The Ki-67 index was significantly higher in MSI-H cancers (P < 0.0001) in which the PI was 90.1 +/- 1.2% (mean +/- SE) compared with 69.5 +/- 3.1% and 69.5 +/- 2.3% in MSI-L and MSS subgroups, respectively. There was a positive linear correlation between the apoptotic index (AI) and PI (r = 0.51; P < 0.001), with MSI-H cancers demonstrating an increased AI:PI ratio indicative of a lower index of cell production. A high PI showed a trend toward predicting improved survival within MSI-H cancers (P = 0.09) but did not predict survival in MSI-L or MSS cancers. The AI was not associated with survival in any MSI subgroup. In conclusion, this is the first study to show that sporadic MSI-H cancers are characterized by a higher AI:PI ratio and increased proliferative activity compared with MSI-L and MSS cancers, and that an elevated PI may confer a survival advantage within the MSI-H subset.

Role of cytokine gene polymorphisms in acute rejection and renal impairment after liver transplantation

Although immunosuppressive regimens are effective, rejection occurs in up to 50% of patients after orthotopic liver transplantation (OLT), and there is concern about side effects from long-term therapy. Knowledge of clinical and immunogenetic variables may allow tailoring of immunosuppressive therapy to patients according to their potential risks. We studied the association between transforming growth factor-beta, interleukin-10, and tumor necrosis factor alpha (TNF-alpha) gene polymorphisms and graft rejection and renal impairment in 121 white liver transplant recipients. Clinical variables were collected retrospectively, and creatinine clearance was estimated using the formula of Cockcroft and Gault. Biallelic polymorphisms were detected using polymerase chain reaction-based methods. Thirty-seven of 121 patients (30.6%) developed at least 1 episode of rejection. Multivariate analysis showed that Child-Pugh score (P =.001), immune-mediated liver disease (P =.018), normal pre-OLT creatinine clearance (P =.037), and fewer HLA class 1 mismatches (P =.038) were independently associated with rejection. Renal impairment occurred in 80% of patients and was moderate or severe in 39%. Clinical variables independently associated with renal impairment were female sex (P =.001), pre-OLT renal dysfunction (P =.0001), and a diagnosis of viral hepatitis (P =.0008). There was a significant difference in the frequency of TNF-alpha-308 alleles among the primary liver diseases. After adjustment for potential confounders and a Bonferroni correction, the association between the TNF-alpha-308 polymorphism and graft rejection approached significance (P =.06). Recipient cytokine genotypes do not have a major independent role in graft rejection or renal impairment after OLT. Additional studies of immunogenetic factors require analysis of large numbers of patients with appropriate phenotypic information to avoid population stratification, which may lead to inappropriate conclusions.

Steatosis and chronic hepatitis C: analysis of fibrosis and stellate cell activation

BACKGROUND/AIMS

Steatosis is a frequent histological finding in chronic hepatitis C and is associated with increased hepatic fibrosis.

METHODS

We studied 80 patients with untreated chronic hepatitis C to determine whether steatosis contributes to fibrosis through a steatohepatitis-like pathway.

RESULTS

Fine sinusoidal and/or central vein fibrosis was present in 52 patients (65%). This was typically located in acinar zone 3 and had a chicken-wire appearance similar to that seen in steatohepatitis. A statistically significant relationship was found between subsinusoidal fibrosis and age (r(s) = 0.33, P = 0.003) and grade of steatosis (r(s) = 0.35, P = 0.001). Mean body mass index was higher in patients with focal (28.4 +/- 4.7 kg/m2) or extensive (29.6 +/- 5.9 kg/m2) subsinusoidal fibrosis than in those patients with no subsinusoidal fibrosis (25.5 +/- 3.7 kg/m2). The extent of alpha-smooth muscle actin staining (as a marker of stellate cell activation) correlated with the degree of portal inflammation and the stage of portal fibrosis, but not with the grade of hepatic steatosis.

CONCLUSIONS

These findings suggest that in hepatitis C infection, host factors, particularly adiposity, contribute to both steatosis and acinar fibrosis. The implication of these observations is that weight reduction may provide an important therapeutic strategy for patients with chronic hepatitis C.

Predictive factors of age at menopause in a large Australian twin study

Various studies have investigated potential predictors of age at natural menopause but have produced inconsistent results. The relationship between age at natural menopause and socioeconomic, reproductive, and health behavioral factors was evaluated using longitudinal data from 5961 Australian female twins, aged 17 to 88 years at the time of study. The sample consisted of women voluntarily enrolled in the Australian Twin Registry. Failure-time analysis was the principal statistical method used to handle censored observations. Kaplan-Meier estimates showed the overall median age at natural menopause to be 51 years (95% confidence interval, 50-51). Median age at menopause was earlier for women with earlier birth year, women with late age of menarche, women who had no children, or women who were smokers. Differences in age at menopause between social, occupational, and educational groups were statistically significant (Mantel-Cox test, p < 0.001) for education, major occupational classification, combined income, and self-rated social class, with higher age at menopause for higher levels of each variable. A Cox proportional hazards model was used to estimate the odds ratio of the occurrence of natural menopause among different sub-groups, adjusted to reflect simultaneous effects of all other significant covariates. This large study provided clear trends of association in predictors relating to age at menopause. These trends may help to resolve uncertainties and conflicting results identified in studies of comparable white samples. The nature of the twin data also sets a solid background for future analyses of genetic and environmental variance components using statistical modeling or related methods.

Synthesis and antimicrobial activity of N-Mannich bases of 3-[N'-sulphadoximino] isatin and its methyl derivative

Schiff's bases of isatin and 5-methyl isatin with sulphadoxine and then its N-Mannich bases were synthesised and evaluated for their anti-microbial activity. The piperidonemethyl group improved the activity and most of the compounds were more potent than the pure drugs.

Effect of phentolamine and propranolol on the survival of experimental skin flaps

The effect of phentolamine and/or propranolol (alpha- and beta-receptor blocking compounds respectively) on the survival of skin flaps was studied in rats. Phentolamine and/or propranolol were injected intraperitoneally every 12 hours, starting one day before the flap operation, and continued for 5 consecutive days. One week after the operation the survival of the flaps was judged. Systemic treatment with either compound alone or in combination resulted in statistically significant increased survival of the flaps. The results demonstrate that both alpha- and beta-adrenergic receptors influence the survival of skin flaps in rats.