Case-control studies of sporadic cryptosporidiosis in Melbourne and Adelaide, Australia

Few studies have assessed risk factors for sporadic cryptosporidiosis in industrialized countries, even though it may be numerically more common than outbreaks of disease. We carried out case-control studies assessing risk factors for sporadic disease in Melbourne and Adelaide, which have water supplies from different ends of the raw water spectrum. In addition to examining drinking water, we assessed several other exposures. 201 cases and 795 controls were recruited for Melbourne and 134 cases and 536 controls were recruited for Adelaide. Risk factors were similar for the two cities, with swimming in public pools and contact with a person with diarrhoea being most important. The consumption of plain tap water was not found to be associated with disease. This study emphasizes the need for regular public health messages to the public and swimming pool managers in an attempt to prevent sporadic cryptosporidiosis, as well as outbreaks of disease.

Perceptions of body hair on white women: effects of labeling

This study examined 118 college students' perceptions of a White woman with body hair as a function of two different possible attributions. Participants reacted to a video of a young woman described as being either a feminist or as having a medical condition that hindered shaving. Students rated the woman on a variety of interpersonal traits. Analysis showed a main effect for body hair and for description but no interaction. The woman with body hair, whether for feminist or alternative reasons, was rated as significantly less friendly, moral, and relaxed, as well as more aggressive, unsociable, strong, nonconformist, dominant, assertive, independent, and in better physical condition than the same woman without body hair. Implications and directions for research are suggested.

Biologic variability of sperm DNA denaturation in infertile men

OBJECTIVES

To examine sperm DNA denaturation (DD) in fertile and infertile men and assess the variability of conventional semen parameters and sperm DD in repeated semen samples from infertile men.

METHODS

Twenty-one consecutive nonazoospermic, infertile men each submitted two semen samples, 2 to 6 weeks apart. We examined semen samples from consecutive fertile men (n = 10) presenting for vasectomy as controls. Standard semen parameters (World Health Organization criteria) and sperm chromatin structure (evaluated by flow cytometry analysis of acridine orange-treated spermatozoa and expressed as the percentage of spermatozoa with denatured DNA) were monitored.

RESULTS

Fertile men had a significantly higher sperm concentration and percentage of sperm motility and a significantly lower percentage of sperm with DD than did infertile men (36 +/- 5.2 x 10(6)/mL versus 12.5 +/- 2.2 x 10(6)/mL, 60.0% +/- 5.2% versus 30.1% +/- 4.1%, and 8.9% +/- 1.9% versus 20.3% +/- 2.5%, respectively, P <0.05). The sperm concentration, sperm motility, and percentage of spermatozoa with DD were not significantly different between the first and second semen samples from the infertile men. Sperm DD showed the lowest average within-subject coefficient of variation (SD/mean), followed by motility and concentration (coefficient of variation 21%, 24%, and 35%, respectively).

CONCLUSIONS

Our data demonstrate that infertile men have significantly higher sperm DD compared with fertile men and that sperm DD exhibits a low coefficient of variation ( approximately 20%) on repeated assessment. These data suggest that sperm DD has a relatively low degree of biologic variability.

High-resolution endoscopic imaging of the GI tract: a comparative study of optical coherence tomography versus high-frequency catheter probe EUS

BACKGROUND

Both optical coherence tomography (OCT) and catheter probe EUS (CPEUS) are candidates for high-resolution imaging of the GI wall, but their potential roles in this clinical context have not been investigated.

METHODS

OCT and CPEUS were used to image normal-appearing portions of the GI tract at the same sites. CPEUS was performed with a 20-MHz or a new 30-MHz catheter probe.

RESULTS

Forty-four histologically confirmed normal sites in 27 patients were evaluated. With OCT, mucosa and muscularis mucosa were clearly seen at all sites. Except for stomach, OCT demonstrated the submucosa in all sites. OCT penetration ranged from 0.7 to 0.9 mm. Microscopic structures such as esophageal glands, intestinal villi, colonic crypts, and blood vessels were easily identified. CPEUS penetration ranged from 10 mm to 20 mm, and 5 to 7 distinct layers were discernible. However, both mucosa and submucosa were seen as thin layers without microscopic detail.

CONCLUSION

OCT resolution is superior to high-frequency CPEUS, but depth of penetration is limited to mucosa and submucosa. OCT images the major structural components of the mucosa and submucosa whereas CPEUS does not. Potentially, OCT and high-frequency CPEUS may be complementary for clinical imaging.

22q13 deletion syndrome

We have recently collected clinical information on 37 individuals with deletion of 22q13 and compared the features of these individuals with 24 previously reported cases. The features most frequently associated with this deletion are global developmental delay, generalized hypotonia, absent or severely delayed speech, and normal to advanced growth. Minor anomalies include dolicocephaly, abnormal ears, ptosis, dysplastic toenails, and relatively large hands. As with many terminal deletions involving pale G-band regions, the deletion can be extremely subtle and can go undetected on routine cytogenetic analysis. In fact, 32% of the individuals in our study had previous chromosome analyses that failed to detect the deletion. Eight of 37 individuals had deletion of 22q13 secondary to an unbalanced chromosome translocation. In the newborn, this deletion should be considered in cases of hypotonia for which other common causes have been excluded. In the older child, this syndrome should be suspected in individuals with normal growth, profound developmental delay, absent or delayed speech, and minor dysmorphic features. We recommend high-resolution chromosome analysis and fluorescence in situ hybridization studies, or molecular analysis to exclude this diagnosis.

Testing for colon neoplasia susceptibility variants at the human COX2 locus

BACKGROUND

Siblings and other first-degree relatives of patients with "sporadic" (i.e., apparently nonfamilial) colorectal cancer or precursor adenomatous colon polyps have an increased risk of developing colon neoplasia. This observation suggests the presence of inherited genetic determinants for sporadic colon neoplasia. Mice homozygous for a null cyclooxygenase 2 (COX2) (also called PTGS2) allele have a dramatically reduced susceptibility to the development of intestinal adenomas. In humans, use of pharmacologic inhibitors of COX2 enzyme activity are associated with reduced risk of colon neoplasia. This study examined whether the human COX2 locus may be linked to colon neoplasia in humans.

METHODS

We used the affected sibling-pair method to test for linkage of the human COX2 locus to colon neoplasia.

RESULTS

We examined 74 concordantly affected sibling pairs from 46 sibships with colon neoplasia. One hundred five siblings from these sibships were diagnosed with either colorectal cancer or colon adenomatous polyps before age 65 years. No linkage between COX2 and colon neoplasia was found by use of a multipoint model-free linkage analysis (estimate of allele sharing was 0.44; standard error = +/-0.04; 95% confidence interval = 0.36 to 0.52). Moreover, even allowing for heterogeneity, the potential that a COX2 colon neoplasia susceptibility variant was present within a substantial subset of these sibships was strongly excluded under either a recessive or a dominant inheritance model (95% confidence to exclude a model in which 2.7% or more of the sibling pairs harbor a dominant susceptibility allele).

CONCLUSIONS

This study of concordantly affected sibling pairs thus demonstrates that variations in the COX2 gene are unlikely to be a source of individual susceptibility to colon neoplasia in humans.

Methylation of the CDH1 promoter as the second genetic hit in hereditary diffuse gastric cancer

Aberrant promoter methylation and the associated loss of gene expression is a common accompaniment of human cancers. Nonetheless, it has been challenging to demonstrate in any given tumour that methylation of a specific gene was causal and not consequent to malignant transformation. In this regard, our attention was drawn to the genesis of gastric cancers in individuals with hereditary diffuse gastric cancer (HDGC). These individuals harbour germline mutations in the gene encoding E-cadherin, CDH1, but their cancers have consistently demonstrated absence of loss of heterozygosity at the CDH1 locus. These findings suggested the hypothesis that CDH1 promoter methylation might function as the 'second genetic hit' in the genesis of these cancers.

Methylene blue-directed biopsies improve detection of intestinal metaplasia and dysplasia in Barrett's esophagus

BACKGROUND

Endoscopically applied methylene blue selectively stains specialized columnar epithelium in Barrett's esophagus.

METHODS

The diagnostic yield and cost of cancer surveillance in patients with Barrett's esophagus using methylene blue-directed biopsies (MBDB) were compared with surveillance using a "jumbo" random biopsy technique in a prospective, sequential, controlled trial. Esophagogastroduodenoscopy was performed with either MBDB or random biopsy in a randomized sequence. The proportions of various types of epithelia in each biopsy were estimated and dysplasia was graded in a blinded fashion.

RESULTS

Forty-three patients with short- (n = 8), limited- (n = 10), and long-segment (n = 25) Barrett's esophagus were studied. Using MBDB technique, the average number of biopsies obtained per patient was significantly lower and the proportion of specialized columnar epithelium in each specimen was significantly higher compared with random biopsy. Dysplasia or cancer was diagnosed in significantly more MBDB specimens (12% vs. 6%, p = 0.004). Despite fewer biopsies per patient using MBDB, dysplasia or cancer was diagnosed in significantly more patients (44% vs. 28%, p = 0.03) than by random biopsy technique. MBDB cost less and detected more cancers than random biopsy.

CONCLUSIONS

MBDB is a more accurate and cost-effective technique than random biopsy for diagnosing specialized columnar epithelium and dysplasia/cancer, particularly in long-segment Barrett's esophagus.

Endosonographic assessment of multimodality therapy predicts survival of esophageal carcinoma patients

BACKGROUND

Standard endosonographic (EUS) staging criteria are unreliable for staging esophageal carcinoma after neoadjuvant therapy; however, measurement of tumor size reduction can identify patients who have achieved a pathologic response. In the current study the authors prospectively compared survival between patients classified as responders and those classified as nonresponders by EUS.

METHODS

The maximal transverse cross-sectional area of the tumor was measured before and after neoadjuvant therapy in patients who were candidates for multimodality treatment. Response was defined as a > or = 50% reduction in tumor area.

RESULTS

A total of 59 patients at 2 centers were followed for a median of 19 months. EUS assessed response in 34 patients (58%). Overall, responders had a median survival of 17.6 months compared with 14.5 months for nonresponders (P < 0.005). Survival was significantly longer in responders compared with nonresponders in the patient subgroup who underwent surgical resection (19.7 months vs. 14.6 months; P < 0. 005), the patient subgroup with adenocarcinoma (21.4 months vs. 10.8 months; P < 0.005), and the patient subgroup initially classified as having T3N1 disease (17.6 months vs. 14.1 months; P < 0.05). Survival was not found to differ significantly between responders and nonresponders in the subgroup of patients with squamous cell carcinoma. EUS response was the only clinical variable that was associated with survival time in a multivariate analysis (relative hazard = 0.27; P < 0.005).

CONCLUSIONS

Patients with esophageal carcinoma who respond to neoadjuvant treatment as identified by EUS measurement of reduction in tumor size have a significantly better prognosis than nonresponders.

High-resolution endoscopic imaging of the GI tract using optical coherence tomography

BACKGROUND

Optical coherence tomography (OCT) has demonstrated the microscopic structure of the gastrointestinal (GI) tract mucosa and submucosa in vitro. We evaluated a prototype OCT system and assessed the feasibility of OCT in the human GI tract.

METHODS

The 2.4 mm diameter prototype OCT probe, inserted through an endoscope, provides a 360-degree radial scan. Images (6.7 frames/sec) are displayed on a television monitor. Tissue contact is not required. In patients undergoing elective endoscopy, OCT images were obtained of normal mucosa (confirmed by biopsy).

RESULTS

Seventy-two sites were imaged (38 patients): esophagus (21), stomach (12), duodenum (11), terminal ileum (4), colon (15), and rectum (9). Varying the distance between the probe and the mucosal surface produced images of the GI wall of varying depth. When held about 1 mm above the mucosal surface, the images consisted of mucosal structures such as colonic crypts, gastric pits, and duodenal villi. With the probe held against the wall, the OCT image comprised several layers interpreted as mucosa, muscularis mucosae, and submucosa. Structures including blood vessels were evident within the submucosa. A probe with a 0.5 mm working distance to the focal point provided the best images. Reducing the frame rate to 4.0 per second facilitated image interpretation.

CONCLUSIONS

OCT is feasible in the human GI tract and provides interpretable high-resolution images of mucosa and submucosa.