Immunoblotting using multiple antigens is essential to demonstrate the true risk of Helicobacter pylori infection for gastric cancer

BACKGROUND

Enzyme-linked immunosorbent assays (ELISAs) for detection of Helicobacter pylori infection, using IgG antibodies, may significantly underestimate the association with gastric cancer.

AIM

To compare associations between H. pylori and cardia (CGC) and noncardia gastric cancer (NCGC) using ELISA and immunoblotting and determine the effect of atrophic gastritis on detection.

METHODS

Nested case-control study within the Melbourne Collaborative Cohort Study. Helicobacter pylori antibodies were detected in subjects with CGC (n = 18), NCGC (n = 34) and controls (n = 69 and 134 respectively) using ELISA (pylori DTect) and immunoblot (Helicoblot 2.1). Pepsinogen I levels were measured using ELISA.

RESULTS

Using ELISA, H. pylori-positivity in the CGC group was 33% vs. 35% in controls [odds ratio (OR = 0.9, 95% CI: 0.3-2.7)], while that in the NCGC group was 79% vs. 63% in controls [OR = 2.3 (95% CI: 0.9-5.8)]. Based on immunoblotting, H. pylori-positivity in the CGC group was 44% vs. 39% in their controls [OR = 1.2 (95% CI: 0.4-3.4)], while that in the NCGC group was 94% vs. 63% in controls [OR = 10.6 (95% CI: 2.4-47.4)]. Pepsinogen I levels in the NCGC cases and controls showed the lowest median level (4 ng/mL) to be in subjects negative by ELISA but positive by immunoblotting.

CONCLUSION

Immunoblotting improves the accuracy of H. pylori studies involving gastric cancer.

Prebiotics enhance survival and prolong the retention period of specific probiotic inocula in an in vivo murine model

AIM

To identify novel prebiotics that could be used to maintain persistence of three representative probiotic strains in vivo.

METHODS AND RESULTS

Test mice were treated with prebiotics soybean oligosaccharide (SOS), fructooligosaccharide (FOS) or inulin, followed by probiotics Lactobacillus acidophilus LAFTI L10 (L10), Bifidobacterium lactis LAFTI B94 (B94) or Lactobacillus casei L26 LAFTI (L26). Faecal samples were then collected and analysed using selective medium and PCR analysis to determine the presence of the probiotic strains. In contrast to the control groups, in mice fed prebiotics, the survival and retention time of the test probiotics was increased extensively. SOS and FOS prolonged the retention period of L10 from 24 to 30 h. Of the three prebiotics, FOS gave the best result with B94, prolonging the retention period from 3 to > or =10 days. Of the three prebiotics, inulin gave the best result for L26, prolonging the retention period from 2 to > or =6 days.

CONCLUSIONS

The prebiotics SOS, FOS and inulin significantly enhance survival and prolong the retention period of L10, B94 and L26 in vivo.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results demonstrate the potential use of FOS, inulin and SOS as prebiotics in conjunction with the probiotic strains L10, B94 and L26 for new synbiotic products.

Survival and retention of the probiotic Lactobacillus casei LAFTI�L26 in the gastrointestinal tract of the mouse

AIMS

This study aimed to develop methods for the detection of the probiotic Lactobacillus casei LAFTI L26 (L26) from mouse faeces, and to determine the survival and retention time of L26 in the mouse gastrointestinal tract.

METHODS AND RESULTS

A selective medium, de Man Rogosa Sharpe (MRS) + bromocresol green + vancomycin (MGV), was designed for the isolation and enumeration of L26 from faecal samples of mice. PCR primers were designed to confirm the identity of L26-like colonies on MGV. These primers did not produce PCR products from related organisms that grew on MGV. Following the administration of L26 to BALB/c mice, faecal samples were collected and analysed using the designed methods. Survival studies showed viable L26 cells to be present in the faeces of mice for >48 h.

CONCLUSIONS

Our results suggest that L26 is able to survive and be retained within the digestive tract of mice for at least 48 h following oral administration.

SIGNIFICANCE AND IMPACT OF THE STUDY

MGV allows effective recovery of L26 from the background microbiota, including lactobacilli of mice. PCR was used to confirm that L26-like colonies were correctly identified as L26. Given the long retention time of L26 in the gastrointestinal tract of mice, it would appear that this probiotic strain may survive in the human gastrointestinal tract.

Clinical features, diagnosis, treatment and molecular studies in paediatric Cushing's syndrome due to primary nodular adrenocortical hyperplasia

BACKGROUND

Primary nodular adrenocortical hyperplasia (PNAH) is a well recognized, but infrequently studied cause of paediatric Cushing's syndrome (CS).

OBJECTIVE

To assess presentation, diagnosis, radiological imaging, treatment and molecular analysis of patients with childhood-onset CS due to PNAH.

PATIENTS

Four males and two females (median age 12.9 years, range 10.9-16.9 years) were studied.

RESULTS

All had growth failure (mean height SDS -1.2; range -2.5-0.0), weight gain [mean body mass index (BMI) SDS 3.5; range 2.5-4.6] and clinical virilization, while five had hypertension [mean systolic blood pressure (SBP) 130 mmHg, diastolic blood pressure (DBP) 83 mmHg]. One patient had generalized lentigines, one had a tibial chondromyxomatous cyst and two had facial freckling. One patient had a family history of primary nodular adrenocortical disease. The diagnosis of CS was based on elevation of sleeping midnight serum cortisol and urinary free cortisol excretion, and impaired suppression of cortisol on both low- and high-dose dexamethasone suppression tests (DST). All patients had undetectable plasma ACTH with absent responses of both plasma ACTH and serum cortisol to an intravenous (i.v.) corticotrophin-releasing hormone (CRH) test. Computed tomography or magnetic resonance imaging showed normal or small adrenals, with nodules in two patients. All patients underwent bilateral adrenalectomy, performed by open (n = 2) or laparoscopic surgery (n = 4) at a mean of 0.4 years (range 0.2-0.8 years) from diagnosis. Hypercortisolaemia was treated preoperatively by metyrapone alone 0.50-0.75 g/day (n = 4), metyrapone 0.75-1.50 g/day + o'p'DDD/mitotane 1-2 g/day (n = 1), or ketoconazole (n = 1). Adrenal histology showed nodular cortical hyperplasia with shrinkage of intervening cortical tissue and pigmentation, present in four patients. Molecular analysis of the type 1-alpha regulatory subunit of protein kinase A (PRKAR1A) gene revealed a novel germline mutation in one patient. Postadrenalectomy, three patients, had catch-up growth with height velocities increasing from 3.0, 3.9 and 2.5-8.9, 8.3 and 9.0 cm/years, respectively. All six are well at a follow-up (mean 4.0 years; range 0.5-10.8 years).

CONCLUSIONS

PNAH was associated with cushingoid features, virilization and hypertension with a lack of cortisol suppression on high DST, undetectable plasma ACTH and absent cortisol and ACTH responses to CRH. Adrenals were normal or small on imaging. PRKAR1A gene analysis may be helpful in the assessment of these patients.

Differential trafficking of transforming growth factor-beta receptors and ligand in polarized epithelial cells

Epithelial cells in vivo form tight cell-cell associations that spatially separate distinct apical and basolateral domains. These domains provide discrete cellular processes essential for proper tissue and organ development. Using confocal imaging and selective plasma membrane domain activation, the type I and type II transforming growth factor-beta (TGFbeta) receptors were found to be localized specifically at the basolateral surfaces of polarized Madin-Darby canine kidney (MDCK) cells. Receptors concentrated predominantly at the lateral sites of cell-cell contact, adjacent to the gap junctional complex. Cytoplasmic domain truncations for each receptor resulted in the loss of specific lateral domain targeting and dispersion to both the apical and basal domains. Whereas receptors concentrate basolaterally in regions of direct cell-cell contact in nonpolarized MDCK cell monolayers, receptor staining was absent from areas of noncell contact. In contrast to the defined basolateral polarity observed for the TGFbeta receptor complex, TGFbeta ligand secretion was found to be from the apical surfaces. Confocal imaging of MDCK cells with an antibody to TGFbeta1 confirmed a predominant apical localization, with a stark absence at the basal membrane. These findings indicate that cell adhesion regulates the localization of TGFbeta receptors in polarized epithelial cultures and that the response to TGFbeta is dependent upon the spatial distribution and secretion of TGFbeta receptors and ligand, respectively.

Randomized controlled trial evaluating rapid pre-screen of cervical cytology specimens

A randomized controlled trial of 75,355 cervical cytology specimens was performed comparing rapid pre-screen with no pre-screen. While the percentage of cases receiving a final report of definite high-grade abnormality was higher in the no pre-screen arm (no pre-screen = 0.70%, pre-screen = 0.65%), the percentage of cases receiving a final report of possible or definite high-grade abnormality was essentially identical in the two arms of the trial (no pre-screen = 1.22%, pre-screen = 1.21%). In the randomized trial, one extra cytology report of definite high-grade abnormality was made for every 12,568 slides pre-screened. This level of benefit was reduced by about half when rapid pre-screen was adopted as a routine laboratory practice.

Squamous cell carcinoma antigen: a role in the early identification of nodal metastases in men with squamous cell carcinoma of the penis

OBJECTIVE

To evaluate whether serum squamous cell carcinoma antigen (SCCAg) measurements may be of use in identifying nodal metastases in patients with SCC of the penis after treating the primary tumour.

PATIENTS AND METHODS

The levels of SCCAg were analysed in 11 men with penile SCC between 1994 and 2001.

RESULTS

An elevated SCCAg level had a sensitivity of 57% (95% confidence interval, CI, 18-90%) and a specificity of 100% (CI 40-100%) for nodal metastases. Levels of SCCAg increased exponentially in patients who developed nodal metastases after treatment of the primary tumour, and were elevated before clinical or radiological evidence of nodal disease.

CONCLUSION

Either the absolute level or the rate of rise of SCCAg may be a useful tool with which to follow patients after excision of the primary tumour. It may be more sensitive than computed tomography and magnetic resonance imaging in detecting recurrence, but further evaluation is needed.

Influences on the risk of recurrent high grade cervical abnormality

The objective of this study is to determine the risk of recurrent abnormality after a first episode of high-grade epithelial abnormality and its evolution over time in a population setting. Two cohorts were established from a statewide registry. The cervical intraepithelial neoplasia (CIN) cohort comprised 6849 women with a biopsy of CIN 2, 2/3 or 3 (squamous or glandular) during 1990-92. A cohort of 6857 women with negative cytology during 1990-92 was used for comparison. The CIN cohort had a significantly greater rate of subsequent high-grade epithelial abnormality than the negative cohort. The risk increased with age. For women over 50 years at the incident biopsy, the rate ratio for subsequent high-grade epithelial abnormality was 24.45 (95% CI, 7.2, 84.3). The rate of subsequent high-grade epithelial abnormality was greater if the incident biopsy was CIN 3 (rate 13.50 per 1000 person years [95% CI, 12.5, 14.6]) rather than CIN 2 or 2/3 (rate 7.83 per 1000 person years [95% CI, 7.1, 8.7]). The rate ratio for subsequent invasive cancer was 9.46 (95% CI, 2.5, 35.3) when the CIN cohort was compared with the negative cohort. We conclude the risk of recurrent high-grade epithelial abnormality is related to the age and degree of abnormality on the incident biopsy. Screening policies should acknowledge the risk does not diminish with time.

Influences on the risk of recurrent high grade cervical abnormality

The objective of this study is to determine the risk of recurrent abnormality after a first episode of high-grade epithelial abnormality and its evolution over time in a population setting. Two cohorts were established from a statewide registry. The cervical intraepithelial neoplasia (CIN) cohort comprised 6849 women with a biopsy of CIN 2, 2/3 or 3 (squamous or glandular) during 1990–92. A cohort of 6857 women with negative cytology during 1990–92 was used for comparison.

The CIN cohort had a significantly greater rate of subsequent high-grade epithelial abnormality than the negative cohort. The risk increased with age. For women over 50 years at the incident biopsy, the rate ratio for subsequent high-grade epithelial abnormality was 24.45 (95% CI, 7.2, 84.3). The rate of subsequent high-grade epithelial abnormality was greater if the incident biopsy was CIN 3 (rate 13.50 per 1000 person years [95% CI, 12.5, 14.6]) rather than CIN 2 or 2/3 (rate 7.83 per 1000 person years [95% CI, 7.1, 8.7]). The rate ratio for subsequent invasive cancer was 9.46 (95% CI, 2.5, 35.3) when the CIN cohort was compared with the negative cohort. We conclude the risk of recurrent high-grade epithelial abnormality is related to the age and degree of abnormality on the incident biopsy. Screening policies should acknowledge the risk does not diminish with time.

Gastric cancer in sub-Saharan Africa

Gastric cancer has a variable but generally low prevalence in black populations of sub-Saharan Africa, despite a high prevalence of Helicobacter pylori (the 'African enigma'). Evidence from Soweto indicates that the host response to H. pylori may be protective against a virulent organism and that, in most people, H. pylori does not lead to more serious sequelae. This suggests that there may be host protective/inhibitory factors present, which prevent the progression of H. pylori-induced chronic active gastritis to cancer.

Helicobacter pylori--an African perspective

Helicobacter pylori is ubiquitous in Africa, with acquisition in childhood the rule. Despite the prevalence of a virulent strain (in Soweto, most H. pylori organisms are cagA- and vacAS(1)-positive) H. pylori-associated pathology (duodenal ulcer, gastric ulcer and gastric cancer) has a variable, often low distribution in sub-Saharan Africa that does not parallel H. pylori prevalence in the population, suggesting a different natural history from that seen in developed countries. Progression to atrophic gastritis in Africans does not appear to differ from that reported in other regions, but as yet unidentified factors may play a role in inhibiting progression to gastric cancer. Studies have suggested that the specific IgG subclass response to H. pylori is predominately IgG1 (suggestive of a Th2 response), and the Th2 response may provide a protective effect against development of gastric cancer. Host immune mechanisms may be the key to different responses to H. pylori in the developed and developing worlds.

Abnormal cervical cytology in bone marrow transplant recipients

Particular human papillomavirus (HPV) subtypes are implicated in the genesis of abnormal cervical cytology and cervical cancer. While most immunocompetent hosts clear HPV infection with no sequelae, some develop premalignant cytological changes of whom a minority subsequently progress to overt carcinoma. Immunocompromised patients, such as renal allograft recipients and HIV-infected individuals, have a higher rate of cytological abnormalities. This is thought to be due to prolonged persistence of virus due to impaired clearance by the immune system. We undertook a retrospective review of the cervical cytology of all women who underwent BMT at two transplant centres and who had cervical smears performed between 1990 and 1998. The rate of cytological abnormalities was significantly higher than in the general population before BMT (age-adjusted odds ratio (OR) 2.2, P = 0.02) and after BMT (OR 7.0, P < 0.0001). After BMT, allogeneic recipients had a higher rate of abnormalities than did autologous patients (OR 2.6, P = 0.02) although only allogeneic recipients had a higher rate of abnormalities post-BMT compared to pre-BMT (allogeneic OR 6.8, P = 0.004). These observations suggest that pre-transplant disease and treatment factors increase the risk of cytologic abnormalities and that transplant-related factors such as conditioning therapy and immunosuppression further increase this risk. These data suggest that more frequent screening may be required in these at-risk groups, especially allogeneic recipients. Prospective studies are required to further evaluate cytological abnormalities and HPV shedding in these populations.