Aortic dissection, patent ductus arteriosus, iris hypoplasia and brachytelephalangy in a male adolescent

We describe a 14-year-old male with dissection of the descending aorta, bilateral iris hypoplasia, striae distensae and brachytelephalangy, the latter being most marked in the thumbs. Inguinal herniae and a patent ductus arteriosus were surgically repaired in infancy. The pattern of abnormalities may constitute a previously undescribed syndrome. The proband died suddenly at the age of 17 years.

Tamoxifen induces G:C-->T:A mutations in the cII gene in the liver of lambda/lacI transgenic rats but not at 5'-CpG-3' dinucleotide sequences as found in the lacI transgene

Tamoxifen, a rat liver carcinogen, can induce mutations in the lacI gene in the livers of lambda/lacI transgenic rats. However, the presence of persistent tamoxifen adducts on the liver DNA raises the possibility that some contribution to the mutagenesis from ex vivo mutations during the in vitro lacI assay cannot be ruled out. To address this issue, mutagenesis at the cII gene of the transgenic shuttle vector was determined using a selection based assay which is unaffected by the presence of tamoxifen-DNA adducts. Female lambda/lacI transgenic rats were dosed orally with tamoxifen (20 mg/kg body wt) daily for 6 weeks, causing a 3.2-fold increase in the mutant frequency (MF) in the cII gene compared with that obtained with solvent treated animals. This was similar to the MF found previously at the lacI gene and confirms that tamoxifen is mutagenic in vivo. The major class of mutation induced by tamoxifen in the cII gene was G:C-->T:A transversions as was found previously in the lacI gene. However, in the one unreplicated study of mutations in the p53 gene of liver tumours induced by tamoxifen, no G:C-->T:A transversions were found; possible differences between mutagenesis in normal and tumour tissues are explored. The major proportion of the G:C-->T:A transversions occurred at 5'-CpG-3' dinucleotide (CpG) sites in the lacI gene, but not at such sites in the cII gene. The methylation of CpG sites greatly enhances the targeting of deoxyguanosine by carcinogens, thus this finding might be explained by differences in the methylation patterns at their respective CpG sites; however, nothing is known about the methylation status of either the lacI nor the cII gene in this transgenic rat. This study raises the important issue of which target genes (mammalian or transgenic) should be used as endpoints in mammalian mutagenesis assays.

Efficacy of a mouthrinse containing 0.05% cetylpyridinium chloride for the control of plaque and gingivitis: a 6-month clinical study in adults

The objective of this 6-month, double-blind, clinical study, conducted following the American Dental Association (ADA) guidelines, was to provide an assessment of the effectiveness of a newly developed mouthrinse containing 0.05% cetylpyridinium chloride (CPC) for the control of supragingival dental plaque and gingivitis. Adult men and women from the Manchester, England, area were entered in the study, and stratified into two treatment groups (CPC mouthrinse and control mouthrinse), which were balanced for baseline Quigley-Hein Plaque Index scores and baseline Löe-Silness Gingival Index scores. Participants were given an oral prophylaxis and instructed to brush their teeth twice daily (morning and evening) for 1 minute with a soft-bristled toothbrush and fluoride dentifrice provided, immediately followed by rinsing for 30 seconds with 15 cc of their assigned mouthrinse. Examinations for supragingival plaque and gingivitis were conducted after 3 months' and again after 6 months' participation in the study. One hundred eleven participants complied with the protocol and completed the entire 6-month clinical study. At both the 3- and 6-month study examinations, the CPC mouthrinse group exhibited statistically significantly less supragingival plaque and gingivitis than did the control mouthrinse group. At the 6-month examination, the magnitude of these differences met or exceeded 24% for all 4 parameters measured (28.2% for Quigley-Hein Plaque Index, 63.4% for Plaque Severity Index, 24.0% for Löe-Silness Gingival Index, and 66.9% for Gingivitis Severity Index). The magnitude of the reductions in supragingival plaque and gingivitis were adequately large to support a claim of efficacy, in accordance with the criteria provided by the published guidelines of the ADA for the demonstration of the efficacy of a chemotherapeutic agent for the control of supragingival plaque and gingivitis. Thus, the results of this 6-month clinical study support the conclusion that a newly developed mouthrinse containing 0.05% cetylpyridinium chloride provides a statistically significant, clinically relevant level of efficacy for the control of supragingival plaque, and for the control of gingivitis, in accordance with the criteria provided by current ADA guidelines.

Extraction of teeth over 5 years in regularly attending adults

OBJECTIVES

This prospective study was conducted to describe the incidence of tooth extraction in a group of regularly attending adults and to assess factors that are predictive of tooth loss.

METHODS

Baseline and annual incremental clinical data were obtained from 23 general dental practitioners on a group of their regularly attending, dentate adult patients over a 5-year period. The patients completed a postal questionnaire with questions relating to dental health behaviours, attitudes and knowledge, and social factors.

RESULTS

Complete clinical data were obtained from 2799 patients. Four hundred and seventy (17%) patients underwent extractions, 72% of which were posterior teeth. The majority of extractions were for reasons other than caries (79%). Bivariate analyses revealed many significant differences between patients who underwent extractions and those who did not, with respect to the clinical, social, behavioural and attitudinal variables. The logistic regression model for tooth loss included three clinical variables, number of teeth, crowns and sites with recession. Other variables in the final model included the dentist's and patient's prediction of treatment need, having sensitive teeth, having a sweet tooth, living alone and smoking. The sensitivity for the model was 0.57 with specificity 0.72.

CONCLUSIONS

This study is unique in its examination of patients and has highlighted that both clinical and other factors are important in predicting who will undergo extractions. Future investigations should assess the consequence of having extractions in terms of health benefit or detriment.

Asthma management with HFA-BDP (Qvar)

This report reviews the role of hydrofluoroalkane-beclomethasone dipropionate (HFA-BDP; Qvar, 3M, Laughborough) in the management of asthma, based on pharmacokinetic, efficacy and safety clinical trial data presented at a satellite symposium to the European Respiratory Society in 1998. Qvar provides equivalent efficacy and safety to chlorofluorocarbon-BDP at about half the dose.

Interval or permanent nonoperative management of acute type A aortic dissection

HYPOTHESIS

Selected patients with acute type A (ascending) aortic dissection who are treated with delayed operation or nonoperative therapy may have better early and short-term outcomes than was previously expected.

DESIGN AND SETTING

Retrospective cohort at a university hospital.

SUBJECTS

Data on 75 patients with acute or chronic type A aortic dissection treated at one institution from January 1, 1985, to November 30, 1997, were analyzed. Of these 75 patients, 34 (21 male and 13 female, with a mean age of 65.5 years) did not undergo initial operative treatment, and 15 (10 male and 5 female, with a mean age of 72.6 years) never underwent surgery. For the 19 patients who underwent delayed surgery, the mean period between aortic dissection and intervention was 11.4+/-4.83 days. The follow-up period ranged from 0.27 to 149 months, with a mean of 20.2 months.

MAIN OUTCOME MEASURES

Vascular complications, hospital mortality, and early survival.

RESULTS

Reasons for interval delay in surgical treatment included initial misdiagnosis or delay in diagnosis (13 [68%] of 19), need to address significant comorbidity (4 [21%] of 19), and initial refusal of operative intervention (2 [11%] of 19). For the 15 patients treated entirely by medical therapy, reasons for electing nonoperative management included extensive comorbidity (5 [33%] of 15), refusal of surgical intervention (6 [40%] of 15), and misdiagnosis or long delay in diagnosis (4 [27%] of 15). Of the 34 patients, 15 (44%) presented with moderate or severe aortic insufficiency, 5 (14%) had evidence of pericardial effusion, 6 (21%) had evidence of concomitant coronary ischemia on electrocardiogram, and 8 (24%) had extension of the dissection into the descending aorta. Four patients (11.8%) died while in the hospital. Of the 34 patients, 30 (88%) who underwent either delayed or no surgery received aggressive medical treatment (beta-adrenergic blocking agents and afterload-reducing agents) and were discharged from the hospital. All patients who were operative candidates in the interval treatment group survived to reach definitive operation. There was no statistically significant difference in short-term survival between the group of patients undergoing delayed surgery or medical treatment only and the group of 41 patients undergoing early operation (P = .42).

CONCLUSIONS

Immediate surgical therapy is still recommended for acceptable operative candidates with acute type A aortic dissection who seek immediate treatment. However, this study permits the following 2 conclusions: (1) patients with type A aortic dissection who are referred or whose conditions are diagnosed several days after presentation have survived the early dangerous period and can safely undergo surgery semielectively (rather than emergently); and (2) selected patients who are not considered operative candidates and who survive the initial type A aortic dissection without complication may be treated with aggressive medical therapy and achieve acceptable early and short-term outcomes, which is better than previously expected.

Multiple roles for the Wilms' tumor suppressor, WT1

Wilms' tumor is a childhood kidney tumor that is a striking example of the way that cancer may arise through development gone awry. A proportion of these tumors develop as a result of the loss of function mutations in the Wilms' tumor suppressor gene, WT1. Inherited mutations in the WT1 gene can lead to childhood kidney cancer, severe gonadal dysplasia, and life-threatening hypertension. Knockouts show that the gene is essential for the early stages of kidney and gonad formation. These tissues are completely absent in null mice. The WT1 gene encodes numerous protein isoforms, all of which share four zinc fingers. There is a large body of evidence supporting the notion that WT1 is a transcription factor, particularly a transcriptional repressor. Recently, however, we obtained evidence that WT1 colocalizes and is physically associated with splice factors. What is more, one alternative splice isoform of WT1 containing three amino acids, Lys-Thr-Ser (KTS; inserted between zinc fingers 3 and 4) is preferentially associated with splice factors, whereas the other alternative splice version, lacking these three amino acids, preferentially associates with the transcriptional apparatus. Both genetic and evolutionary considerations suggest that these two different forms of the protein have different functions. We will discuss recent evidence to further implicate WT1 in splicing. Our results raise the possibility that regulation of splicing is a crucial factor in the development of the genitourinary system, and that tumors may arise through aberrant splicing. To pursue the regulation and function of WT1 in whole animals, we have been introducing the human gene and large flanking regions cloned in yeast artificial chromosomes directly into mice. These studies have allowed us to dissect the function of WT1 at late as well as at early stages in organogenesis and to identify new sites and surprising new potential functions for the gene.

Bronchogenic carcinoma presenting as a bronchopericardial fistula

A case is reported in which an undiagnosed bronchogenic carcinoma presented clinically with sudden onset shortness of breath and cardiac failure due to the development of an acute bronchopericardial fistula.

Determination of the optimal conditions for dental subtraction radiography using a storage phosphor system

OBJECTIVES

To determine the optimal kVp and exposure conditions for digital subtraction radiography system using a storage phosphor system.

METHOD

Signal-to-noise (SNR) measurements were acquired using a Digora system (Soredex, Helsinki, Finland) of large area, low contrast, clinically realistic details against varying degrees of background attenuation for both single exposure unsubtracted and subtracted images. These results were combined with a measure of estimated thyroid dose to derive a figure of merit (FOM) for the unsubtracted and subtracted images.

RESULTS

For both unsubtracted and subtraction radiography, an exposure at 50 kVp and 250 muGy produce the best overall FOM. However, using the system at the 60 kVp maximum a FOM at 1000 muGy for unsubtracted radiography and 500 muGy for subtraction radiography gave the best SNR performance.

CONCLUSION

Operating parameters have been derived which allow the user to choose between optimising SNR and dose (50 kVp, 250 muGy for unsubtracted and subtracted radiography) or SNR alone (60 kVp, 1000 muGy for unsubtracted and 60 kVp, 500 muGy for subtracted), for the visualisation of clinically representative details using the Digora system.

Evaluating screening policies for the early detection of retinopathy in patients with non-insulin dependent diabetes

Retinopathy is a common complication of insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes, but serious visual loss may be prevented or delayed with sufficiently early diagnosis and treatment. Screening for early signs of retinopathy is clearly beneficial for some people, but there is no established consensus about who should be screened, by whom, by what technique and with what frequency, especially for NIDDM. The model described in this paper simulates the development of eye disease in a population of NIDDM patients and the effects of different screening schemes in terms of years of sight saved and the numbers of people prevented from suffering severe visual loss. The initial results indicate that blanket screening of all NIDDM patients may not be effective.

Improvements in delivery with an extra fine beclomethasone aerosol

The reformulation of beclomethasone dipropionate (BDP) in a chlorofluorocarbon (CFC)-free propellant, hydrofluoroalkane (HFA), has resulted in improved delivery of medication to the large and small airways, the target site of action of anti-asthmatic therapy. It is hypothesised that this improved delivery of BDP to the airways will translate into improved clinical efficacy in comparison with the previous CFC formulation. This paper reviews the results of three large-scale clinical trials that were designed to test this hypothesis by comparing the efficacy of various doses of Qvar (3M Pharmaceuticals' HFA-BDP formulation) with CFC-BDP in asthmatic patients. It was found that the dose-response relationship of Qvar is shifted to the left compared with CFC-BDP, such that equivalent improvements in asthma control are seen with half the daily dose of Qvar compared with the CFC formulation.

Electropotential measurements as a new diagnostic modality for breast cancer

BACKGROUND

Proliferative changes in breast epithelium are an intrinsic aspect in the development of breast cancer, and result in regions of epithelial electrical depolarisation within the breast parenchyma, which can extend to the skin surface. Diagnostic information might be obtained from a non-imaging and non-invasive test based on skin-surface electropotentials.

METHODS

In 661 women, scheduled for open biopsy at eight European centres, we studied whether measurements of breast electrical activity with surface sensors could distinguish benign from malignant breast disease. A depolarisation index was developed.

RESULTS

We found a highly significant trend of progressive electrical changes according to the proliferative characteristics of the biopsied tissue. Discriminatory information was obtained in both premenopausal and postmenopausal women, and the index was not related to age. The best test performances were for women with palpable lesions. The median index was 0.398 for non-proliferative benign lesions, 0.531 for proliferative benign lesions, and 0.644 for cancer (ductal carcinoma-in-situ and invasive). A specificity of 55% was obtained at 90% sensitivity for women with palpable lesions when a discriminant based on age and the depolarisation index was used.

INTERPRETATION

This new modality may have diagnostic value, especially in reducing the number of unnecessary diagnostic tests among women with inconclusive findings on physical examination. Understanding and control of the biological variability of these electrical phenomena will be important in the improvement of this test. Studies in populations with a lower cancer prevalence are needed to assess further the diagnostic value of this approach.

Safety of irbesartan in the treatment of mild to moderate systemic hypertension

Nine multicenter, randomized, placebo-controlled studies were conducted to evaluate the safety and tolerability of the angiotensin II subtype 1 receptor blocker (AT1 blocker) irbesartan for the treatment of mild to moderate hypertension. After a 4- to 5-week placebo lead-in phase, patients were randomized to 4 to 12 weeks of double-blind therapy with either placebo (n = 641) or irbesartan (n = 1,965) at doses of 1 to 900 mg orally. All doses of irbesartan were well tolerated with no evidence of dose-related adverse effects. Across the full recommended clinical dose range, although not statistically significantly different, irbesartan use was associated with a lower incidence of adverse events, serious adverse events, and discontinuations due to adverse events compared with placebo. No clinically significant or unexpected changes in laboratory analyses were observed. Withdrawal of irbesartan therapy did not result in rebound hypertension or clinically important adverse events. Thus, irbesartan use in hypertensive patients was associated with a placebo-like safety and tolerability profile.

Differential effects of mucosal pH on human (Caco-2) intestinal epithelial cell motility, proliferation, and differentiation

Mucosal pH abnormalities are associated with anastomotic dehiscence, ischemia, and malignancy. We postulated that intraluminal pH influences intestinal epithelial motility, proliferation, and differentiation and studied extracellular pHo (7.0-8.5) effects on human (Caco-2) intestinal epithelial motility, proliferation, and differentiation. Mucosal healing was modeled by sheet migration and differentiation by alkaline phosphatase and dipeptidyl dipeptidase specific activity. In parallel differentiation and motility studies, we inhibited proliferation with mitomycin to dissociate indirect mitogenic effects. Intracellular pHi was quantitated using BCECF/AM at varying extracellular pHo and in migrating cells. Motility was maximal at pHo 7.6 and proliferation at 7.2. Each decreased with acidity and alkalinity. By contrast, brush border enzyme activity was lowest at pHo 7.0 and highest at pHo 8.5. pHi was highest at pHo 8.5. Migrating cell pHi was higher than static cell pHi. Thus, extracellular pHo deviations perturb Caco-2 pHi homeostasis and motility. Alkalinity promotes differentiation while acidity induces proliferation and limits differentiation.

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.