How to use Chlamydia antibody testing in subfertility patients

Screening for tubal factor subfertility by means of Chlamydia antibody testing (CAT) was introduced into the initial work-up of subfertile couples several years ago. The results reported, however, are heterogeneous, and no uniformity exists in cut-off levels of titres, or in definitions of tubal factor subfertility. We performed a prospective cohort study to evaluate the implications of varying the definitions of tubal pathology and of modifying the cut-off levels on the clinical impact of CAT in predicting tubal factor subfertility. In 227 consecutive patients who attended our fertility clinic, the Chlamydia IgG antibody titre was determined and related to tuboperitoneal abnormalities at laparoscopy as a reference standard. According to received operating characteristic (ROC) curve analysis, a titre of 16 is the optimum cut-off level. Increasing the cut-off level improves specificity and positive likelihood ratio (LR+), at the expense of sensitivity and negative LR (LR-). Changing the definition of tubal factor subfertility from unspecified tuboperitoneal abnormalities into extensive adhesions and/or bilateral distal tubal occlusion improves LR+, LR- and kappa significantly. We conclude that CAT is more accurate in predicting severe distal tubal pathology than unspecified tuboperitoneal abnormalities. Although from a statistical point of view a titre of 16 is the optimum cut-off level, from a clinical point of view 32 or 64 may be preferable, depending on the aim of screening and the inception cohort.      

Malignancy may adversely influence the quality and behaviour of oocytes

A case series of eight cycles of in-vitro fertilization (IVF) in five women diagnosed with malignant disorders is presented. These patients chose to defer definitive treatment for a chance for preservation of potential fertility. The response of these patients to ovarian stimulation, and the outcome, was compared with 17 IVF cycles in 12 age- matched patients with isolated tubal infertility. An apparent adverse influence of malignant disease on the quality and behaviour of oocytes was observed. Despite a comparable total number of oocytes per cycle in the two groups, a significantly reduced percentage of mature oocytes was retrieved per cycle from patients with malignant diseases. The oocytes from patients with malignant disorders were of a poorer quality and exhibited a significantly impaired fertilization rate compared to the controls. We propose that neoplastic processes, irrespective of the site or cell of origin, may have a detrimental impact on the biology of oocytes, an effect akin to that seen on spermatozoa in men with certain malignancies.      

Distribution of mutations in the PEX gene in families with X-linked hypophosphataemic rickets (HYP)

Mutations in the PEX gene at Xp22.1 (phosphate-regulating gene with homologies to endopeptidases, on the X-chromosome), are responsible for X-linked hypophosphataemic rickets (HYP). Homology of PEX to the M13 family of Zn2+ metallopeptidases which include neprilysin (NEP) as prototype, has raised important questions regarding PEX function at the molecular level. The aim of this study was to analyse 99 HYP families for PEX gene mutations, and to correlate predicted changes in the protein structure with Zn2+ metallopeptidase gene function. Primers flanking 22 characterised exons were used to amplify DNA by PCR, and SSCP was then used to screen for mutations. Deletions, insertions, nonsense mutations, stop codons and splice mutations occurred in 83% of families screened for in all 22 exons, and 51% of a separate set of families screened in 17 PEX gene exons. Missense mutations in four regions of the gene were informative regarding function, with one mutation in the Zn2+-binding site predicted to alter substrate enzyme interaction and catalysis. Computer analysis of the remaining mutations predicted changes in secondary structure, N-glycosylation, protein phosphorylation and catalytic site molecular structure. The wide range of mutations that align with regions required for protease activity in NEP suggests that PEX also functions as a protease, and may act by processing factor(s) involved in bone mineral metabolism.      

Postmenopausal estrogen use, cigarette smoking, and cardiovascular morbidity in women over 50. The Framingham Study

We studied the effect of estrogen use on morbidity from cardiovascular disease in 1234 postmenopausal women, aged 50 to 83 years, participating in the Framingham Heart Study's 12th biennial examination (index examination). The medication history recorded at biennial examinations 8 through 12 was used to classify the degree of estrogen exposure before eight years of observation for cardiovascular morbidity and mortality. Despite a favorable cardiovascular risk profile and control for the major known risk factors for heart disease, women reporting postmenopausal estrogen use at one or more examinations had over a 50 per cent elevated risk of cardiovascular morbidity (P less than 0.01) and more than a twofold risk for cerebrovascular disease (P less than 0.01) after the index examination. Increased rates for myocardial infarction (P less than 0.05) were observed particularly among the estrogen users who smoked cigarettes. Conversely, among nonsmokers estrogen use was associated only with an increased incidence of stroke (P less than 0.05). No benefits from estrogen use were observed in the study group; in particular, mortality from all causes and from cardiovascular disease did not differ for estrogen users and nonusers.     

Alternative splicing of exon 14 determines nuclear or cytoplasmic localisation of fmr1 protein isoforms

Impaired expression of the FMR1 gene is responsible for the fragile X mental retardation syndrome. The FMR1 gene encodes a cytoplasmic protein with RNA-binding properties. Its complex alternative splicing leads to several isoforms, whose abundance and specific functions in the cell are not known. We have cloned in expression vectors, cDNAs corresponding to several isoforms. Western blot comparison of the pattern of endogenous FMR1 proteins with these transfected isoforms allowed the tentative identification of the major endogenous isoform as ISO 7 and of a minor band as an isoform lacking exon 14 sequences (ISO 6 or ISO 12), while some other isoforms (ISO 4, ISO 5) were not expressed at detectable levels. Surprisingly, in immunofluorescence studies, the transfected splice variants that exclude exon 14 sequences (and have alternate C-terminal regions) were shown to be nuclear. Such differential localisation was however not seen in subcellular fractionation studies. Analysis of various deletion mutants suggests the presence of a cytoplasmic retention domain encoded in exon 14 and of a nuclear association domain encoded within the first eight exons that appear however to lack a typical nuclear localisation signal.      

Murine model of pulmonary anthrax: kinetics of dissemination, histopathology, and mouse strain susceptibility

Bioweapons are most often designed for delivery to the lung, although this route is not the usual portal of entry for many of the pathogens in the natural environment. Vaccines and therapeutics that are efficacious for natural routes of infection may not be effective against the pulmonary route. Pulmonary models are needed to investigate the importance of specific bacterial genes in virulence, to identify components of the host immune system that are important in providing innate and acquired protection, and for testing diagnostic and therapeutic strategies. This report describes the characteristics of host and Bacillus anthracis interactions in a murine pulmonary-infection model. The infective dose varied depending on the route and method of inoculation. The germination process in the lung began within 1 h of inoculation into the lung, although growth within the lung was limited. B. anthracis was found in the lung-associated lymph nodes approximately 5 h after infection. Minimal pneumonitis was associated with the lung infection, but significant systemic pathology was noted after dissemination. Infected mice typically succumbed to infection approximately 3 to 4 days after inoculation. The 50% lethal doses differed among inbred strains of mice, but within a given mouse strain, neither the age nor the sex of the mice influenced susceptibility to B. anthracis.     

A Web-based compendium of clinical questions and medical evidence to educate internal medicine residents.

The authors designed an electronic database of clinical questions (CQs) and medical evidence and implemented it in 2001-02 at Duke University Medical Center and the Veterans Administration Medical Center in Durham, North Carolina. This Web-based data collection system is called the Critical Appraisal Resource (CAR) and is still in operation. This report is of ten months of the system's operation. During their medicine ward rotations, residents entered CQs into the CAR; they also entered Medline reference links and validated article summaries. Residents' utilization of the CAR database, Medline, and other electronic resources was prospectively measured. In addition, residents were prospectively surveyed regarding the impact of each question and associated reference on medical decision making for individual patients. Over ten months, residents entered 625 patient-based CQs into the CAR and were able to obtain useful information from the medical literature on 82% of the CQs they searched. The two most prevalent CQ types were therapy and diagnosis questions (53% and 22%). Sixty percent of the therapy articles considered useful were reports of randomized controlled trials. Residents obtained 77% of their useful data from Medline. They reported that obtaining useful data altered patient management 47% of the time. Residents used the CAR as a resource, searching the database for information 1,035 times over the study period. In summary, the use of an evidence-based critical appraisal resource led residents to engage the medical literature on behalf of their patients and influenced approximately half of their patient-care decisions. Residents benefited from questions previously searched by other residents, allowing them to address a wider spectrum of CQs during ward rotations.