Anaesthetist prediction of postoperative opioid use: a multicentre prospective cohort study

Background

The Apfel simplified risk score includes four risk factors: female sex, non-smoking status, postoperative nausea and vomiting or motion sickness history, and postoperative opioid use. The score is calculated preoperatively, so postoperative opioid use must be predicted. We aimed to determine whether anaesthetists can predict patients' postoperative opioid use and dose.

Methods

Specialist anaesthetists from eight hospitals preoperatively predicted opioid use and dose in the post-anaesthesia care unit (PACU) and for the first 24 h postoperatively, which was compared with actual opioid use and dose. Opioid doses were converted to oral morphine equivalents (MEQ). Correlations between predicted and actual opioid use and dose were analysed with Spearman's rho and linear regression.

Results

A total of 487 anaesthetist-patient pairs were included. Anaesthetists overpredicted opioid use (398 [82%] predicted vs 251 [52%] actual patients requiring opioids in the PACU; 396 [81%] predicted vs 291 [60%] actual in the first 24 h) (Spearman's rho [95% confidence interval] 0.24 [0.16-0.33], P<0.001 in the PACU; 0.36 [0.28-0.44], P<0.001 in the first 24 h). Anaesthetists also overpredicted opioid dose (median [inter-quartile range] 12 [8-20] mg predicted MEQ vs 4 [0-18] mg actual MEQ in the PACU; 32 [18-60] mg vs 24 [0-65] mg MEQ in the first 24 h) (Spearman's rho 0.21 [0.13-0.29], P<0.001 in the PACU; 0.53 [0.40-0.60], P<0.001 in the first 24 h).

Conclusions

Specialist anaesthetists cannot accurately predict opioid use or dose in the PACU or the first 24 postoperative hours. The Apfel risk criterion for postoperative opioid use may be inaccurate in clinical practice.

Optimisation of Sample Preparation from Primary Mouse Tissue to Maintain RNA Integrity for Methods Examining Translational Control

The protein output of different mRNAs can vary by two orders of magnitude; therefore, it is critical to understand the processes that control gene expression operating at the level of translation. Translatome-wide techniques, such as polysome profiling and ribosome profiling, are key methods for determining the translation rates occurring on specific mRNAs. These techniques are now widely used in cell lines; however, they are underutilised in tissues and cancer models. Ribonuclease (RNase) expression is often found to be higher in complex primary tissues in comparison to cell lines. Methods used to preserve RNA during lysis often use denaturing conditions, which need to be avoided when maintaining the interaction and position of the ribosome with the mRNA is required. Here, we detail the cell lysis conditions that produce high-quality RNA from several different tissues covering a range of endogenous RNase expression levels. We highlight the importance of RNA integrity for accurate determination of the global translation status of the cell as determined by polysome gradients and discuss key aspects to optimise for accurate assessment of the translatome from primary mouse tissue.

Assessing the Impact of Substandard and Falsified Antimalarials in Benin

Substandard and falsified antimalarials contribute to the global malaria burden by increasing the risk of treatment failures, adverse events, unnecessary health expenditures, and avertable deaths, yet no study has examined this impact in western francophone Africa to date. In Benin, where malaria remains endemic and is the leading cause of mortality among children younger than 5 years, there is a lack of robust data to combat the issue effectively and inform policy decisions. We adapted the Substandard and Falsified Antimalarial Research Impact model to assess the health and economic impact of poor-quality antimalarials in this population. The model simulates population characteristics, malaria infection, care-seeking behavior, disease progression, treatment outcomes, and associated costs of malaria. We estimated approximately 1.8 million cases of malaria in Benin among children younger than 5 years, which cost $193 million (95% CI, $192-$193 million) in treatment costs and productivity losses annually. Substandard and falsified antimalarials were responsible for 11% (n = 693) of deaths and nearly $20.8 million in annual costs. Moreover, we found that replacing all antimalarials with quality-ensured artemisinin combination therapies (ACTs) could result in $29.6 million in cost savings and prevent 1,038 deaths per year. These results highlight the value of improving access to quality-ensured artemisinin combination therapies for malaria treatment and increasing care-seeking in Benin. Policymakers and key stakeholders should use these findings to advocate for increased access to quality-ensured antimalarials, inform policies and interventions to improve health-care access and quality, and reduce the burden of malaria.

Invasive placebos in research on peripheral nerve blocks: a follow-up study

INTRODUCTION

The Serious Harm and Morbidity "SHAM" grading system has previously been proposed to categorize the risks associated with the use of invasive placebos in peripheral nerve block research. SHAM grades range from 0 (no potential complications, eg, using standard analgesia techniques as a comparator) through to 4 (risk of major complications, eg, performing a sub-Tenon's block and injecting normal saline). A study in 2011 found that 52% of studies of peripheral nerve blocks had SHAM grades of 3 or more.

METHODS

We repeated the original study by allocating SHAM grades to randomized controlled studies of peripheral nerve blocks published in English over a 22-month period. Documentation was made of the number of study participants, age, number of controls, body region, adverse events due to invasive placebos and any discussion regarding the ethics of using invasive placebos. We compared the proportion of studies with SHAM grades of 3 or more with the original study.

RESULTS

In this current study, 114 studies fulfilled the inclusion criteria, 5 pediatric and 109 adult. The SHAM grade was ≥3 in 38 studies (33.3%), with 1494 patients in these control groups collectively. Several studies discussed their reasons for choosing a non-invasive placebo. No pediatric studies had a SHAM grade of ≥3.

CONCLUSIONS

The use of invasive placebos that may be associated with serious risks in peripheral nerve block research has decreased in contemporary peripheral nerve block research.

Multi parametric biophysical assessment of treatment effects on xerotic skin

Background

Topical moisturizing products are widely used to alleviate the problems associated with xerotic skin. Their use affects many properties of the stratum corneum (SC) in a complex and interrelated manner. The range of measurement techniques available to the researcher has increased in recent years. However, few studies have looked for correlations between the different techniques for assessing how aspects of xerotic skin change over time as a result of topical moisturizer usage.

Objectives

A 3‐week in vivo study using an oil‐in‐water based moisturizing product and an untreated site was conducted to determine the clinical significance of and any correlations between a range of different approaches for the measurement of skin lipid content and also skin hydration and visual grading of dry skin.

Methods

A range of traditional and more recently developed skin measurement techniques have been used to examine a variety of SC properties in normal and xerotic skin during topical moisturizer usage.

Results

In vivo confocal Raman spectroscopy and analysis of SC lipids from tape strips both showed an increase in SC lipid level and organization after 3 weeks of moisturizer usage on xerotic skin. Hydration, measured both optically and electrically, also increased and skin barrier function improved, with strong correlations between the different measures of dryness being observed.

Conclusions

Strong correlations were observed between the skin measurements for lipid assessment and skin hydration with regard to the assessment of xerotic skin, providing valuable new information for future in vivo clinical research into dry and atopic skin.

Keywords

biophysical assessment, skin barrier, skin hydration, topical moisturizers, Xerosis

Correction to: Incentivizing appropriate malaria case management in the private sector: a study protocol for two linked cluster randomized controlled trials to evaluate provider- and client-focused interventions in western Kenya and Lagos, Nigeria

An amendment to this paper has been published and can be accessed via the original article.

Incentivizing appropriate malaria case management in the private sector: a study protocol for two linked cluster randomized controlled trials to evaluate provider- and client-focused interventions in western Kenya and Lagos, Nigeria

Background

A large proportion of artemisinin-combination therapy (ACT) anti-malarial medicines is consumed by individuals that do not have malaria. The over-consumption of ACTs is largely driven by retail sales in high malaria-endemic countries to clients who have not received a confirmatory diagnosis. This study aims to target ACT sales to clients receiving a confirmatory diagnosis using malaria rapid diagnostic tests (mRDTs) at retail outlets in Kenya and Nigeria.

Methods

This study comprises two linked four-arm 2 × 2 factorial cluster randomized controlled trials focused on malaria diagnostic testing and conditional ACT subsidies with the goal to evaluate provider-directed and client-directed interventions. The linked trials will be conducted at two contrasting study sites: a rural region around Webuye in western Kenya and the urban center of Lagos, Nigeria. Clusters are 41 and 48 participating retail outlets in Kenya and Nigeria, respectively. Clients seeking care at participating outlets across all arms will be given the option of paying for a mRDT—at a study-recommended price—to be conducted at the outlet. In the provider-directed intervention arm, the outlet owner receives a small monetary incentive to perform the mRDT. In the client-directed intervention arm, the client receives a free ACT if they purchase an mRDT and receive a positive test result. Finally, the fourth study arm combines both the provider- and client-directed interventions. The diagnosis and treatment choices made during each transaction will be captured using a mobile phone app. Study outcomes will be collected through exit interviews with clients, who sought care for febrile illness, at each of the enrolled retail outlets.

Results

The primary outcome measure is the proportion of all ACTs that are sold to malaria test-positive clients in each study arm. For all secondary outcomes, we will evaluate the degree to which the interventions affect purchasing behavior among people seeking care for a febrile illness at the retail outlet.

Conclusions

If our study demonstrates that malaria case management can be improved in the retail sector, it could reduce overconsumption of ACTs and enhance targeting of publicly funded treatment reimbursements, lowering the economic barrier to appropriate diagnosis and treatment for patients with malaria.

Trial registration

ClinicalTrials.govNCT04428307, registered June 9, 2020, and NCT04428385, registered June 9, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13012-020-01077-w.

Infant peripherally inserted central catheter insertion without general anesthesia

BACKGROUND

Avoiding anesthesia for infant peripherally inserted central catheter insertion beyond the neonatal period has been the subject of very little research despite this being a high-risk age group. In our institution, we introduced a "Fast, Feed, and Wrap" technique, previously described for magnetic resonance imaging scans, for infants up to 6 months and weighing under 5.5 kg undergoing peripherally inserted central catheter insertion.

AIMS

The aim was to report our experience using "Fast, Feed, and Wrap," in particular the success rate and proportion of qualifying infants who were managed this way.

METHODS

A retrospective study was undertaken using electronic records and case notes to determine patient age, weight, indication for procedure, anesthetic technique (general anesthesia or "Fast, Feed, and Wrap"), peripherally inserted central catheter details (site of insertion, gauge, and number of lumens), and length of procedure.

RESULTS

Fifty-one infants qualified for "Fast, Feed, and Wrap" over a 42-month period, 43 were attempted this way and 40 were successful. All infants were greater than 40 weeks postconceptual age at the time of peripherally inserted central catheter insertion under "Fast, Feed, and Wrap," though 26% were preterm. The average age of babies undergoing "Fast, Feed, and Wrap" was 35 days (IQR 18-55), and the median weight was 3.78 kg (IQR 3.48-4.77).

CONCLUSIONS

Infants younger than 6 months and under 5.5 kg can be managed without general anesthesia for peripherally inserted central catheter insertion using a Fast, Feed, and Wrap technique.

Repression of the Type I Interferon Pathway Underlies MYC- and KRAS-Dependent Evasion of NK and B Cells in Pancreatic Ductal Adenocarcinoma

MYC is implicated in the development and progression of pancreatic cancer, yet the precise level of MYC deregulation required to contribute to tumor development has been difficult to define. We used modestly elevated expression of human MYC, driven from the Rosa26 locus, to investigate the pancreatic phenotypes arising in mice from an approximation of MYC trisomy. We show that this level of MYC alone suffices to drive pancreatic neuroendocrine tumors, and to accelerate progression of KRAS-initiated precursor lesions to metastatic pancreatic ductal adenocarcinoma (PDAC). Our phenotype exposed suppression of the type I interferon (IFN) pathway by the combined actions of MYC and KRAS, and we present evidence of repressive MYC-MIZ1 complexes binding directly to the promoters of the genes encodiing the type I IFN regulators IRF5, IRF7, STAT1, and STAT2. Derepression of IFN regulator genes allows pancreatic tumor infiltration by B and natural killer (NK) cells, resulting in increased survival. SIGNIFICANCE: We define herein a novel mechanism of evasion of NK cell-mediated immunity through the combined actions of endogenously expressed mutant KRAS and modestly deregulated expression of MYC, via suppression of the type I IFN pathway. Restoration of IFN signaling may improve outcomes for patients with PDAC.This article is highlighted in the In This Issue feature, p. 747.

The ERBB network facilitates KRAS-driven lung tumorigenesis

KRAS is the most frequently mutated driver oncogene in human adenocarcinoma of the lung. There are presently no clinically proven strategies for treatment of KRAS-driven lung cancer. Activating mutations in KRAS are thought to confer independence from upstream signaling; however, recent data suggest that this independence may not be absolute. We show that initiation and progression of KRAS-driven lung tumors require input from ERBB family receptor tyrosine kinases (RTKs): Multiple ERBB RTKs are expressed and active from the earliest stages of KRAS-driven lung tumor development, and treatment with a multi-ERBB inhibitor suppresses formation of KRAS^G12D-driven lung tumors. We present evidence that ERBB activity amplifies signaling through the core RAS pathway, supporting proliferation of KRAS-mutant tumor cells in culture and progression to invasive disease in vivo. Brief pharmacological inhibition of the ERBB network enhances the therapeutic benefit of MEK (mitogen-activated protein kinase kinase) inhibition in an autochthonous tumor setting. Our data suggest that lung cancer patients with KRAS-driven disease may benefit from inclusion of multi-ERBB inhibitors in rationally designed treatment strategies.

Deposition of plant lipids after single application of a lip care product determined by confocal raman spectroscopy, corneometry and transepidermal water-loss

OBJECTIVE

Lip treatment products often incorporate oils and waxes in their formulations, and a desired outcome of their use is to prevent lip dryness and roughness as well as help to repair this condition. The objective of this study was to combine confocal Raman spectroscopy with skin capacitance (corneometry) and transepidermal water loss (closed chamber Aquaflux system) measurements, in the evaluation of the degree of moisturization and lip skin penetration of a fruit wax (Rhus vernicula peel cera) and natural oil-based (Cocos nucifera fruit oil and Olea europea oil) lip care product, following a single application.

METHODS

The study was conducted on a total of 15 healthy female volunteers. Instrumental measurements were performed before and 30 min, 2 h and 6 h after a single application of the product.

RESULTS

Lip skin barrier function as well as lip hydration were significantly improved and penetration of olive oil was maintained for at least 6 h post product application. The deposition of the three component lipids (berry fruit wax, coconut oil and olive oil) into the stratum corneum after a single application of the lip care product was maintained and data significant for 2-6 h post product application. Lipid deposition was regarded as a positive long-lasting skin care (depot-) effect combined with a profound hydrating effect for about 6 h.

CONCLUSION

The tri-method approach taken in this study is deemed relevant and valid for measuring lip hydration offering a complimentary assessment of the barrier function of lip skin and interactive effects of cosmetic ingredients.

Meeting report: Emerging respiratory viral infections and nonhuman primate case reports

A workshop on Emerging Respiratory Viral Infections and Spontaneous Diseases in nonhuman primates was sponsored by the concurrent Annual Meetings of the American College of Veterinary Pathologists and the American Society for Veterinary Clinical Pathology, held December 1-5, 2012, in Seattle, Washington. The session had platform presentations from Drs Karen Terio, Thijs Kuiken, Guy Boivin, and Robert Palermo that focused on naturally occurring influenza, human respiratory syncytial virus, and metapneumovirus in wild and zoo-housed great apes; the molecular biology and pathology of these viral respiratory diseases in nonhuman primate (NHP) models; and the therapeutic and vaccine approaches to prevention and control of these emerging respiratory viral infections. These formal presentations were followed by presentations of 14 unique case studies of rare or newly observed spontaneous lesions in NHPs (see online files for access to digital whole-slide images corresponding to each case report at http://scanscope.com/ACVP%20Slide%20Seminars/2012/Primate%20Pathology/view.apml). The session was attended by meeting participants that included students, pathology trainees, and experienced pathologists from academia and industry with an interest in respiratory and spontaneous diseases of NHPs.

Stereotactic body radiation therapy (SBRT) for clinically localized prostate cancer: the Georgetown University experience

Background

Stereotactic body radiation therapy (SBRT) delivers fewer high-dose fractions of radiation which may be radiobiologically favorable to conventional low-dose fractions commonly used for prostate cancer radiotherapy. We report our early experience using SBRT for localized prostate cancer.

Methods

Patients treated with SBRT from June 2008 to May 2010 at Georgetown University Hospital for localized prostate carcinoma, with or without the use of androgen deprivation therapy (ADT), were included in this retrospective review of data that was prospectively collected in an institutional database. Treatment was delivered using the CyberKnife® with doses of 35 Gy or 36.25 Gy in 5 fractions. Biochemical control was assessed using the Phoenix definition. Toxicities were recorded and scored using the CTCAE v.3. Quality of life was assessed before and after treatment using the Short Form-12 Health Survey (SF-12), the American Urological Association Symptom Score (AUA) and Sexual Health Inventory for Men (SHIM) questionnaires. Late urinary symptom flare was defined as an AUA score ≥ 15 with an increase of ≥ 5 points above baseline six months after the completion of SBRT.

Results

One hundred patients (37 low-, 55 intermediate- and 8 high-risk according to the D’Amico classification) at a median age of 69 years (range, 48–90 years) received SBRT, with 11 patients receiving ADT. The median pre-treatment prostate-specific antigen (PSA) was 6.2 ng/ml (range, 1.9-31.6 ng/ml) and the median follow-up was 2.3 years (range, 1.4-3.5 years). At 2 years, median PSA decreased to 0.49 ng/ml (range, 0.1-1.9 ng/ml). Benign PSA bounce occurred in 31% of patients. There was one biochemical failure in a high-risk patient, yielding a two-year actuarial biochemical relapse free survival of 99%. The 2-year actuarial incidence rates of GI and GU toxicity ≥ grade 2 were 1% and 31%, respectively. A median baseline AUA symptom score of 8 significantly increased to 11 at 1 month (p = 0.001), however returned to baseline at 3 months (p = 0.60). Twenty one percent of patients experienced a late transient urinary symptom flare in the first two years following treatment. Of patients who were sexually potent prior to treatment, 79% maintained potency at 2 years post-treatment.

Conclusions

SBRT for clinically localized prostate cancer was well tolerated, with an early biochemical response similar to other radiation therapy treatments. Benign PSA bounces were common. Late GI and GU toxicity rates were comparable to conventionally fractionated radiation therapy and brachytherapy. Late urinary symptom flares were observed but the majority resolved with conservative management. A high percentage of men who were potent prior to treatment remained potent two years following treatment.

A case-control study of risk of leukaemia in relation to mobile phone use

Background:

Mobile phone use is now ubiquitous, and scientific reviews have recommended research into its relation to leukaemia risk, but no large studies have been conducted.

Methods:

In a case–control study in South East England to investigate the relation of acute and non-lymphocytic leukaemia risk to mobile phone use, 806 cases with leukaemia incident 2003–2009 at ages 18–59 years (50% of those identified as eligible) and 585 non-blood relatives as controls (provided by 392 cases) were interviewed about mobile phone use and other potentially aetiological variables.

Results:

No association was found between regular mobile phone use and risk of leukaemia (odds ratio (OR)=1.06, 95% confidence interval (CI)=0.76, 1.46). Analyses of risk in relation to years since first use, lifetime years of use, cumulative number of calls and cumulative hours of use produced no significantly raised risks, and there was no evidence of any trends. A non-significantly raised risk was found in people who first used a phone 15 or more years ago (OR=1.87, 95% CI=0.96, 3.63). Separate analyses of analogue and digital phone use and leukaemia subtype produced similar results to those overall.

Conclusion:

This study suggests that use of mobile phones does not increase leukaemia risk, although the possibility of an effect after long-term use, while biologically unlikely, remains open.

Blood glucose changes and memory: effects of manipulating emotionality and mental effort

Increasing the emotionality of target material often facilitates memory performance which may be linked to the liberation of glucose. Conversely, increasing mental effort leads to reduced performance and measurable falls in blood glucose. A 2 x 2, parallel groups experiment examined these two phenomena directly by assessing blood glucose levels and memory for neutral and emotional word lists, both with and without a secondary task. Co-performing the secondary task significantly reduced blood glucose in the neutral word condition only and resulted in a global reduction of memory performance in both neutral and emotional word conditions. Processing emotional material resulted in significantly raised blood glucose levels, however, there was no advantage for memory of emotional words. A follow-up study confirmed that the emotionality manipulation was effective. We conclude that there exists a clear relationship between reduced blood glucose and impaired memory performance during periods of mental effort. However, the relationship between physiological and cognitive processes associated with processing emotional material are more complex.

Second to fourth digit ratio, testosterone and perceived male dominance

Previous studies have shown that male faces with extreme features associated with testosterone are perceived as dominant and masculine. Women have been reported to prefer more masculinized male faces as they may consider testosterone markers to be an 'honest' indication of good health, and such considerations may underlie their aesthetic preferences. However, pronounced testosterone facial markers are also associated with dominance, and several negative personality traits. This suggests that female aesthetic preferences may be an adaptive compromise between positive attributes associated with higher than average testosterone, and negative attributes associated with more extreme masculinization. This current study attempts to clarify the role of hormone markers in female perceptions of dominance, masculinity and attractiveness, in male facial images. Recent evidence suggests that the relative length of the 2nd to 4th finger (2D : 4D ratio) is a pointer to prenatal testosterone levels and may thus serve as a window to the prenatal hormonal environment. We measured 2D : 4D in a sample of male college students and took salivary samples to analyse circulating levels of testosterone. Women rated facial images of these males for dominance, masculinity and attractiveness. Our results show that male 2D : 4D was significantly negatively related to perceived dominance and masculinity but not attractiveness. Circulating testosterone levels were not related to dominance, masculinity or attractiveness. These findings suggest that: (i) high prenatal levels of testosterone serve to 'organize' male facial features to subsequently reflect dominance and masculine characteristics presumably activated during puberty; and (ii) attractiveness is not directly related to testosterone levels. We conclude that facial dominance and masculinity reflect a male's perceived status rather than his physical attraction to women.

Pre-eclampsia: a predisposing factor for neonatal venous sinus thrombosis?

Neonatal venous sinus thrombosis is a well-recognized, but infrequently diagnosed, cause of neonatal encephalopathy. Previous reports have tended to omit reference to the importance of maternal factors in predisposing the infant to this condition. This report, in which eight patients with neonatal venous sinus thrombosis are presented, will reveal a strong association between pre-eclampsia, prothrombotic disorders, and neonatal venous sinus thrombosis. Contrary to previously published reports, there is a high likelihood of neurodevelopmental residua after this condition.

Informed choice in fragile X syndrome and its effects on prevalence

We present the effect of case finding, cascade testing, and counselling for fragile X syndrome in a population of 6.5 million over a decade. Carrier females made informed choices that resulted in a 10-fold decrease in the prevalence of affected males in their offspring.

The reproducibility of colour-coded duplex scanning in measuring arterial wall dimensions

Intimal hyperplasia continues to be a major problem following vascular surgery but experimental evidence suggests that it can be reduced pharmacologically. For clinical studies an accurate, reproducible and non-invasive image of the intima and lumen is required. We have assessed the value of the Acuson 128 Colour Duplex for such studies. Ten patients had their common femoral arteries scanned at a fixed point by two experienced observers on two separate occasions. External vessel diameter, luminal diameter and internal diameter (i.e. the diameter within the internal elastic lamina) were measured in both longitudinal and cross-sectional views. Cross-sectional area and degree of stenosis were all measured and all parameters expressed as limits of agreement. The mean external diameter of the common femoral arteries was 10.5 +/- 1.6 mm. Measurements in the longitudinal view were highly reproducible with limits of agreement ranging from -0.67 - +0.25 mm (internal diameter) to -1.49 - +1.31 mm (luminal diameter). In order to detect a meaningful change in longitudinal external diameter a real difference of 0.86 mm is required representing a change of less than 10%. Cross-sectional diameter measurements were similarly reproducible (-0.73 - +0.47 mm to -1.97 - +1.79 mm). However, cross-sectional area measurements had a wide variation so that the error in degree of stenosis was -25.4 - +30.2%. Thus, duplex ultrasound reproducibly images the layers of the arterial wall. Prospective studies of intimal hyperplasia are feasible but must be based on longitudinal and cross-sectional diameters rather than cross-sectional areas.

Population screening for fragile X

A screening programme to detect fragile X syndrome has been operating in New South Wales, Australia, since 1984. The aim of this programme is to find previously unidentified individuals with the syndrome so that their extended families can be properly informed of the risks before making decisions about childbearing. 14,225 individuals attending adult and child facilities for the intellectually handicapped have been screened, of whom 8172 have been offered testing for the fragile X syndrome with a 79% uptake of the service. 253 probands were found, and in the extended families 818 females at 25-100% risk of being carriers were interviewed and counselled. Continuing contact was maintained and prenatal diagnosis was offered. The effect of the programme was assessed in a subgroup of 90 individuals, most of whom were appreciative of the service and felt that they had been adequately informed. The influence of knowing the diagnosis and its genetic implications were also assessed, the main consequences being a 26% reduction in births and a 61% uptake of prenatal diagnosis. Improved techniques for diagnosis of fragile X have benefited the families identified and counselled, suggesting that systematic screening for fragile X should be an essential component of community genetic services.

Mortality in the fragile X syndrome: preliminary data

Mortality was studied among 348 males and 433 females who had or who carried the gene for the fragile X syndrome. The average age of death was about 12 years lower than in the general population for both men and women but this was likely a bias of ascertainment. The commonest causes of death were cardiovascular, cerebrovascular and malignant disease similar to those in the general population. No evidence for any specific disease susceptibility was found in this preliminary study.

Clinical screening score for the fragile X (Martin-Bell) syndrome

A clinical score based on the manifestations of the fragile(X) syndrome has been formulated and applied to all individuals included in a fragile(X) case finding program in New South Wales. The total score can vary from 0 to 10. Individuals are scored 0, 1, or 2 in each of 5 categories considered indicative of the fragile(X) phenotype: family history of intellectual handicap, face length, ear configuration, personality, and body habitus. In a study of 1,206 individuals where the clinical scores were prospective (i.e., they had been given before the cytogenetic results were known) the percentage of those with the fragile(X) increased from 0.6% of those with scores of 4 or less to 14.6% with scores 5-7 and to 67% of those with scores 8-10. We have found the score simple to use in the circumstances where screening takes place (sheltered workshops and schools) and have reduced the number of individuals tested cytogenetically by 45%.

Screening for the fragile X: how many cells should we analyse?

Since nationwide screening for the fragile X would involve the analysis of thousands of individuals within a short period of time, the number of cells, N, which should be analysed is of fundamental importance. When selecting N, the crucial parameter should be the degree of expression of the fragile site in the affected individuals in the population to be screened. However, this degree of expression is not known, and for routine diagnostic purposes, N = 100 has been accepted by many centers. By taking data from two large series of affected males/females with a known degree of expression (one series from New South Wales, one from Belgium), we have estimated the fraction of affected males/females which would have been missed if the two series were rescreened with the analysis of less than 100 cells. Assuming that the degree of expression within these two series is similar to the degree of expression in all affected individuals within the two populations, the results indicate that a reduction of N in a screening program, say from 100 to 50 cells, would reduce the detection rate between 1 and 5%. The reduction would be greater in females than in males, and greater in the Belgian than in the Australian population.

Prenatal diagnosis of the fragile X--the Australasian experience

Identification of increasing numbers of females heterozygous for fragile X linked mental retardation together with improved genetic counselling is creating a growing demand for prenatal diagnosis of fra(X). However, present cytogenetic techniques are somewhat unreliable and our collaborative approach has endeavoured to improve quality of cell culture systems and the sensitivity of fra(X) detection. Since 1985 we have exchanged cell cultures between our laboratories for verification of diagnostic results and comparison of induction techniques and have benefitted from larger numbers of cells scored for fra(X). Our 50 cases represent almost all of such studies undertaken in Australasia (Australia and New Zealand). Ten cases were unequivocally fra(X) positive; there was discrepancy between laboratories in 4 cases and one false-negative case. We propose a protocol to enhance fra(X) detection and conclude that, provided care is exercised, couples at risk of a fra(X) pregnancy can benefit from prenatal cytogenetic diagnosis.

Investigation of the twinning rate in families with the fragile X syndrome

An excess of twins in families with the Martin-Bell or fra(X) syndrome was noted previously in one family study [Fryns, 1986]. We tried to confirm this observation in a second large sample of families from a different population. We calculated the number of twin births among the total number of live births of known obligate carriers found in fra(X) families ascertained in New South Wales, Australia. We only included births of known sex and excluded triplets. There were 5 male pairs, 3 female pairs and 9 unlike sex pairs of twins born among 752 live births. Thus the twining rate was 1/44 per live birth. We compared this rate to that found in two different types of individuals: 1) the rate of 1/96 which was obtained from the 1985 vital statistics for New South Wales, and 2) the rate 1/75 obtained from a sample of live births of obligate carriers with hemophilia A. The increase in twinning among heterozygotes with the fra(X) was highly significant when compared to the census data (p less than 0.001). However, it was not significantly different from that in the hemophilia data (p less than 0.05) which were collected in the same way as in the fra(X) families.

Is there a fragile(X) negative Martin-Bell syndrome?

During the course of the preventative screening program for the fra(X) syndrome, we identified 32 men with the phenotype but who were fra(X) negative. These were reviewed and none fitted the full criteria, so we were unable to confirm the existence of the fra(X) negative Martin-Bell syndrome. The literature and 4 families previously thought to have the fra(X) negative Martin-Bell syndrome were also reviewed. We were unable to make a concrete diagnosis of the fra(X) negative Martin-Bell syndrome.

Investigation of the segregation of the fragile X mutation in daughters of obligate carrier women

Two reports have suggested that over 50% of the offspring of obligate carrier women receive the mutation for the fra(X) or the Martin-Bell syndrome [Webb et al, 1986; Fryns, 1984]. Such a segregation distortion is difficult to assess for the fra(X) syndrome because of incomplete penetrance, variable expression and probable ascertainment biases. We have attempted to evaluate this possible segregation distortion in daughters of obligate carriers in a large sample of sibships ascertained in a survey of New South Wales, Australia. We used two definitions of expression: 1) presence of fra(X) positive cells if daughters were tested cytogenetically, and 2) mental impairment if daughters were not tested cytogenetically. The segregation frequency was estimated in different types of sibships of obligate carriers based on the way they were ascertained. This was done in order to have an internal check on possible ascertainment biases. Among the 189 cytogenetically tested daughters, 81 were fra(X) positive. Among the 97 untested daughters, 24 were mentally impaired in some way. Therefore, the segregation frequency as defined by fra(X) expression and/or mental impairment was 37%. Thus, no evidence was detected for segregation distortion. These data were significantly different than those collected by Webb et al [1986] and scored by the same method as the present data set.

Treadmill testing in the assessment of peripheral arterial disease

A treadmill exercise test is used in many vascular laboratories to measure the claudication time and the total walking time of patients with intermittent claudication. Three hundred and nine consecutive outpatients in the peripheral arterial disease clinic were assessed on the treadmill. Fifty-nine were unable to walk on it at all, and of the remaining 250 patients, 68 (27%) could manage five minutes of treadmill exercise, and 87 (35%) patients stopped for reasons other than intermittent claudication. Only 95 (38%) stopped walking within five minutes as a result of intermittent claudication. Fifty of these 95 patients were retested approximately 10 days later and the mean change from day 1 to day 2 in the claudication time and in the total walking time was calculated to establish the normal range. From these results, if a treadmill is to be used to infer any improvement, we calculate that the claudication time must increase by at least 63 seconds and the total walking time by 93 seconds. Treadmill testing for the assessment of symptoms, if it is used at all, should be used in conjunction with objective methods of assessment.

Preventive screening for the fragile X syndrome

In an Australian population of 1.2 million, we screened 1977 intellectually handicapped persons, who were identified through the public schools and sheltered workshops, for the X-linked semidominant fragile X syndrome. We excluded 527 because they had another known diagnosis. The remaining 1450 were offered chromosomal analysis. Of the 1117 who consented (77 percent), an additional 196 were excluded, and among the 921 who were tested cytogenetically, 40 probands were found. Prevalence rates for persons with an intellectual handicap and the fragile X syndrome in the public school population were 1:2610 for males and 1:4221 for females. Family studies identified 84 women who were either obligate carriers or at high risk of being carriers, who were under the age of 35 and had no children. These women were given genetic counseling, and the availability of antenatal diagnosis was explained to them. If each of these 84 women had two children, 27 of their sons would have an intellectual handicap. We recommend cytogenetic screening for the fragile X syndrome in all currently identified intellectually handicapped people, followed by routine screening of children newly identified as intellectually handicapped in the school system.

Risk factors in carotid artery stenosis and intracranial aneurysms

Hyperlipoproteinaemia is an important risk factor in extracranial arterial disease and the mean values of serum triglyceride and serum cholesterol were raised in a group of 43 patients with carotid stenosis. The risk factors for carotid stenosis are not unlike those for other types of atherosclerotic disease such as dilating arterial disease. Serum triglyceride and cholesterol levels in a group of 22 patients with intracranial aneurysms are similar to those of age and sex matched control patients and are significantly lower than those of a group of 69 patients with dilating arterial disease. It is suggested that the aetiology of these two aneurysmal diseases may be different. 55% of the patients with intracranial aneurysms were hypertensive and only 50% were heavy smokers. This is a much lower incidence of cigarette smoking than in patients with either carotid stenosis or dilating disease. We conclude that intracranial aneurysms are unlikely to be caused by atherosclerosis.

Temperature-sensitive mutants of foot-and-mouth disease virus: the isolation of mutants and observations on their properties and genetic recombination

A number of temperature-sensitive mutants were isolated from two strains of foot-and-mouth disease virus (FMDV). Various properties of the mutants were examined including comparative growth curves at permissive and restrictive temperatures, cut-off temperatures, thermal lability and pH sensitivity. Recombination was observed between various pairs of mutants of FMDV strain Pacheco. It occurred early in the growth cycle and the proportion of recombinants remained constant thereafter. Maximum recombination was achieved if the input multiplicity of each virus was 6 p.f.u./cell or greater, provided the ratio of the input multiplicities did not vary by more than a factor of two. Day-to-day variations could be substantially reduced by normalizing recombination frequencies in terms of a standard cross. The results suggested that genetic mapping was possible with two-or three-factor crosses.