RELATION BETWEEN THE VIRULENCE OF STREPTOCOCCI AND HEMOLYSIN

Strains of streptococci whose virulence has been increased for any one species of animal do not produce greater concentrations of hemolysin than the original strain. Furthermore, there is a tendency for the original culture to grow more rapidly than the more pathogenic form, and to reach the height of hemolysin production at an earlier stage during the growth of the culture. These conclusions can probably be applied only to experiments in which the serum used in the media is from some species not employed for the animal passages.

How cost-effective is 'No Smoking Day'?

OBJECTIVE

To obtain a more rigorous estimate of the cost-effectiveness of No Smoking Day (NSD), an annual UK-wide campaign to encourage smokers to quit, than has been possible hitherto.

DESIGN

Comparison of reported quit attempts in the month following NSD for three consecutive years with adjacent months using repeated national surveys of quit attempts.

SETTING

England.

PARTICIPANTS

A total of 1309 adults who had smoked in the past year who responded to the surveys in the month following NSD (April 2007-2009) and a comparison group of 2672 adults who smoked in the past year who responded to the survey in the two adjacent months (March and May 2007-2009).

MAIN OUTCOME MEASURES

The number of additional smokers who quit permanently in response to NSD was estimated from the survey results. The incremental cost-effectiveness ratio (ICER) was calculated by combining this estimate with established estimates of life years gained and the known costs of NSD.

RESULTS

The rate of quit attempts was 2.8 percentage points higher in the months following NSD (120/1309) compared with the adjacent months (170/2672; 95% CI 0.99% to 4.62%), leading to an estimated additional 0.07% of the 8.5 million smokers in England quitting permanently in response to NSD. The cost of NSD per smoker was £ 0.088. The discounted life years gained per smoker in the modal age group 35-44 years was 0.00107, resulting in an ICER of £ 82.24 (95% CI 49.7 to 231.6). ICER estimates for other age groups were similar.

CONCLUSIONS

NSD emerges as an extremely cost-effective public health intervention.

Discovery of molecular subtypes in leiomyosarcoma through integrative molecular profiling

Leiomyosarcoma (LMS) is a soft tissue tumor with a significant degree of morphologic and molecular heterogeneity. We used integrative molecular profiling to discover and characterize molecular subtypes of LMS. Gene expression profiling was performed on 51 LMS samples. Unsupervised clustering showed three reproducible LMS clusters. Array comparative genomic hybridization (aCGH) was performed on 20 LMS samples and showed that the molecular subtypes defined by gene expression showed distinct genomic changes. Tumors from the 'muscle-enriched' cluster showed significantly increased copy number changes (P=0.04). A majority of the muscle-enriched cases showed loss at 16q24, which contains Fanconi anemia, complementation group A, known to have an important role in DNA repair, and loss at 1p36, which contains PRDM16, of which loss promotes muscle differentiation. Immunohistochemistry (IHC) was performed on LMS tissue microarrays (n=377) for five markers with high levels of messenger RNA in the muscle-enriched cluster (ACTG2, CASQ2, SLMAP, CFL2 and MYLK) and showed significantly correlated expression of the five proteins (all pairwise P<0.005). Expression of the five markers was associated with improved disease-specific survival in a multivariate Cox regression analysis (P<0.04). In this analysis that combined gene expression profiling, aCGH and IHC, we characterized distinct molecular LMS subtypes, provided insight into their pathogenesis, and identified prognostic biomarkers.

Smoke-free homes in England: prevalence, trends and validation by cotinine in children

OBJECTIVE

To examine the prevalence of smoke-free homes in England between 1996 and 2007 and their impact on children's exposure to second-hand smoke via a series of annual cross-sectional surveys: the Health Survey for England. These comprised nationally representative samples of non-smoking children aged 4-15 (n = 13 365) and their parents interviewed in the home. Main outcome measures were cotinine measured in saliva, smoke-free homes defined by "no" response to "Does anyone smoke inside this house/flat on most days?", self-reported smoking status of parents and self-reported and cotinine validated smoking status in children.

RESULTS

The proportion of homes where one parent was a smoker that were smoke free increased from 21% in 1996 to 37% in 2007, and where both parents were smokers from 6% to 21%. The overwhelming majority of homes with non-smoking parents were smoke free (95% in 1996; 99% in 2007). For children with non-smoking parents and living in a smoke-free home the geometric mean cotinine across all years was 0.22 ng/ml. For children with one smoking parent geometric mean cotinine levels were 0.37 ng/ml when the home was smoke free and 1.67 ng/ml when there was smoking in the home; and for those with two smoking parents, 0.71 ng/ml and 2.46 ng/ml. There were strong trends across years for declines in cotinine concentrations in children in smoke-free homes for the children of smokers and non-smokers.

CONCLUSIONS

There has been a marked secular trend towards smoke-free homes, even when parents themselves are smokers. Living in a smoke-free home offers children a considerable, but not complete, degree of protection against exposure to parental smoking.

Alcoholics' beliefs about responsibility for, and recovery from, their condition

A study was carried out with a sample of in-patients and out-patients in an alcohol treatment programme examining beliefs about where responsibility lay for their condition and recovery from it. Brickman et al. [1] proposed a framework for understanding these beliefs consisting of four 'models'. In each model responsibility for causing the problem and for resolving it is considered either to lie with the individual or with other factors. The results indicated that the alcoholics' beliefs could not readily be understood in terms of this framework. As regards the cause of their condition, belief in the role of luck, personal responsibility and acceptance of a disease model emerged as independent factors. With regard to responsibility for recovery, belief in personal responsibility, the value of treatment and support and the importance of motivation emerged as separate factors. Belief in personal responsibility for causing the problem was significantly associated with acceptance of responsibility for recovery. Adoption of a disease model was negatively associated with belief in the importance of motivation in recovery. Treatment satisfaction was positively correlated with belief in the importance of treatment and support but not other dimensions. Younger patients tended to accept a lower level of personal responsibility for their condition. The results indicate the alcoholics tend to adopt quite specific beliefs about their condition and that satisfaction with a particular treatment regimen is related to belief in the value of treatment rather than any particular model concerning where responsibility for their condition and recovery from it lies.

Modelling the Effect of Minor Orthopaedic Day Surgery on Patient Mood at the Early Post-Operative Period: A Prospective Population-Based Study

Objective:

The effect of minor orthopaedic day surgery (MiODS) on patient's mood.

Methods:

A prospective population-based cohort study of 148 consecutive patients with age above 18 and less than 65, an American Society of Anaesthesiology (ASA) score of 1, and the requirement of General Anaesthesia (GA) were included. The Medical Outcomes Study-Short Form 36 (SF-36), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) were used pre- and postoperatively.

Results:

The mean physical component score of SF-36 before surgery was 45.3 (SD = ±10.1) and 8 weeks following surgery was 44.9 (SD = ±11.04) [n = 148, p = 0.51, 95%CI = (-1.03 -1.52)]. For the measurement of the changes in mood using BDI, BAI and SF-36, latent construct modelling was employed to increase validity. The covariance between mood pre- and post-operatively (cov = 69.44) corresponded to a correlation coefficient, r = 0.88 indicating that patients suffering a greater number of mood symptoms before surgery continue to have a greater number of symptoms following surgery. When the latent mood constructs were permitted to have different means the model fitted well with χ2 (df = 1) = 0.86 for which p = 0.77, thus the null hypothesis that MiODS has no effect on patient mood was rejected.

Conclusions:

MiODS affects patient mood which deteriorates at 8 weeks post-operatively regardless of the pre-operative patient mood state. More importantly patients suffering a greater number of mood symptoms before MiODS continue to have a greater number of symptoms following surgery.

The safety and efficacy of bilateral simultaneous total hip replacement: an analysis of 2063 cases

Comparison of the safety and efficacy of bilateral simultaneous total hip replacement (THR) and that of staged bilateral THR and unilateral THR was conducted using DerSimonian-Laird heterogeneity meta-analysis. A review of the English-language literature identified 23 citations eligible for inclusion. A total of 2063 bilateral simultaneous THR patients were identified. Meta-analysis of homogeneous data revealed no statistically significant differences in the rates of thromboembolic events (p = 0.268 and p = 0.365) and dislocation (p = 0.877) when comparing staged or unilateral with bilateral simultaneous THR procedures. A systematic analysis of heterogeneous data demonstrated that the mean length of hospital stay was shorter after bilateral simultaneous THR. Higher blood transfusion requirements were expected following bilateral simultaneous THR than staged or unilateral THR, and surgical time was not different between groups. This procedure was also found to be economically and functionally efficacious when performed by experienced surgeons in specialist centres.

Sociodemographic differences in triggers to quit smoking: findings from a national survey

OBJECTIVE

Reasons for quitting smoking and triggers that finally precipitate a quit attempt are not necessarily the same thing. We sought to assess variation in reported triggers of attempts to stop smoking as a function of age, gender and socioeconomic status.

METHODS

Cross-sectional household survey in England. A total of 2441 smokers and ex-smokers aged 16 and over, who reported making at least one serious quit attempt in the last 12 months, were recruited. The main outcome measure was participants' responses to the question "What finally triggered your most recent quit attempt?". Respondents selected from a list of options or specified a trigger not on the list.

RESULTS

In the event, smokers typically reported as triggers similar factors as have previously been reported as "reasons". "A concern about future health problems" (28.5%) was the most commonly cited trigger followed by "health problems I had at the time" (18%) and then "a decision that smoking was too expensive" (12.2%). The most common external trigger was advice from a health professional (5.6%). Future health concern was more common in smokers with higher socioeconomic status (SES), whereas cost and current health problems were more often cited by lower SES smokers. Younger smokers were more likely to report their quit attempt being triggered by a TV advertisement while older smokers were more likely to cite advice from a health professional. Concern about future health problems was cited less often by 16 to 24 year olds and those aged 65+ than those aged 25 to 64 years.

CONCLUSIONS

There are significant differences in reported triggers for quit attempts as a function of sociodemographic factors. Most notably, smokers with higher SES are more likely to report concern about future health whereas those from lower SES are more likely to cite cost and current health problems.

The feasibility of measuring puffing behaviour in roll-your-own cigarette smokers

BACKGROUND/OBJECTIVE

Despite the increase in roll-your-own (RYO) cigarette consumption in many countries, very little is known about RYO smokers. In order to estimate the health risks inherent in RYO use, it is important to assess exposure to tobacco toxins in this group. Exposure is determined by a number of factors, including puffing behaviour, but so far this issue has not been addressed among RYO smokers. This study sought both to determine the feasibility of measuring puffing behaviour in this group, its reliability and validity, and to characterise puffing behaviour among RYO smokers compared with smokers of factory-made (FM) cigarettes.

METHODS

At two visits, 24 hours apart, 131 FM and 29 RYO cigarette smokers provided saliva samples that were assayed for cotinine, a measure of nicotine intake and thus smoke exposure. Self-reported puffing behaviour of participants, as well as their demographic and smoking characteristics were also assessed. At the end of the first visit, smokers were shown how to use a portable smoking topography machine that measures puffing behaviour, the CReSSmicro, and asked to smoke all cigarettes with this machine until the second visit, when participants were asked to provide feedback on using the device.

RESULTS

Both RYO and FM cigarette smokers reported that the CReSSmicro was easy to use; however, RYO cigarette smokers were more likely to have missing data, to reduce cigarette consumption and to indicate a change in their puffing behaviour because of the device. Machine-determined puffing behaviour was equally stable over time in both groups with similar ability to predict exposure; cotinine levels were related to machine but not to self-reported puffing parameters. Overall, RYO smokers appeared to puff cigarettes less hard but for longer than FM cigarette smokers.

CONCLUSION

The measurement of puffing behaviour using a topography device is feasible but less practicable for RYO than FM cigarette smokers. Puffing parameters show comparable reliability and validity for both groups of smokers and reveal some differences in smoking topography dependent on the type of cigarette smoked.

New cutpoints to identify increased HER2 copy number: analysis of a large, population-based cohort with long-term follow-up

BACKGROUND

HER2 gene amplification and/or protein overexpression in breast cancer is associated with a poor prognosis and predicts response to anti-HER2 therapy. We examine the natural history of breast cancers in relationship to increased HER2 copy numbers in a large population-based study.

PATIENTS AND METHODS

HER2 status was measured by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in approximately 1,400 breast cancer cases with greater than 15 years of follow-up. Protein expression was evaluated with two different commercially-available antibodies.

RESULTS

We looked for subgroups of breast cancer with different clinical outcomes, based on HER2 FISH amplification ratio. The current HER2 ratio cut point for classifying HER2 positive and negative cases is 2.2. However, we found an increased risk of disease-specific death associated with FISH ratios of >1.5. An 'intermediate' group of cases with HER2 ratios between 1.5 and 2.2 was found to have a significantly better outcome than the conventional 'amplified' group (HER2 ratio >2.2) but a significantly worse outcome than groups with FISH ratios less than 1.5.

CONCLUSION

Breast cancers with increased HER2 copy numbers (low level HER2 amplification), below the currently accepted positive threshold ratio of 2.2, showed a distinct, intermediate outcome when compared to HER2 unamplified tumors and tumors with HER2 ratios greater than 2.2. These findings suggest that a new cut point to determine HER2 positivity, at a ratio of 1.5 (well below the current recommended cut point of 2.2), should be evaluated.

270 STILL GLOWING AFTER ALL THESE YEARS: STORAGE LIFE OFA COMPLETE BOVINE SEXING PCR MIX

Generally, PCR reaction mixes are made fresh on the day of use. This is impractical for field sexing. Mistakes occur due to the required measuring precision and to contamination from environmental DNA. Therefore, we developed a complete reaction mix (YCD). Storage and transport of YCD required liquid N2. No study has determined storage life of PCR reaction mixes in standard freezers. Our study compared 14-year-old bovine YCD (AB Technology, Pullman, WA, USA) stored in a standard freezer to a freshly prepared mix. The working concentration of bovineYCD was: buffer (50 mm Tris, 1% dextran T-500, 50 mm KCl, 2.5 mm MgCl2, and 0.035% 2-mercaptoethanol), deoxyribonucleotides (5µm) (Boehringer Mannheim, Basel, Switzerland), two sets of primers (sexing primers, 5´-GAACTTTCAAGCAGCTGAGGC-3´ and 5´-GATTGTTGATCCCACAGAAGG-3´ (2.5µm), and control primers, 5´-TTGAGGCATGGAACTCCGCT-3´ and 5´-GGTGGTTCCACATTCCGTAGG-3´ (0.25µm) (custom synthesis, IDT Inc, Coralville IA, USA)), and Taq polymerase (Taq p) (2 IU) (AmpliTaq DNA Polymerase, Stoeffel Fragment, Perkin Elmer, Branchburg, NJ, USA). The concentrations in the complete reaction mix were twice the working concentration. The freshly prepared mix was the same as YCD except: deoxyribonucleotides (C01581, GenScript Corp., Piscataway, NJ, USA) and Taq p (M0273L, New England BioLabs, Ipswich, MA, USA). Male and female bovine lymphocytes (100 cells/2 µL) were used as the DNA source. The DNA replication occurred in a Corbett Rapid Thermocycler (Model FTS-IS, Corbett Research, Montlake, Australia) in 20-µL volumes. All assays were run with positive and negative DNA controls. The PCR products were separated using polyacrylamide gel electrophoresis (PAGE). A 6% gel with Tris as the buffer was formed in an agarose gel chamber (M12 Electrophoresis Unit, Edvotek, Bethesda, MD, USA) under argon gas. The gel was run at 200 volts (PS500ST, Hoefer Scientific Instruments, San Francisco, CA, USA) for 30 min, and then stained with 5 µL ethidium bromide in 100 mL of Tris buffer for 30 min. The gel was destained for 30 min in H2O. The gel was viewed using a transilluminator (3–300, Fotodyne, Hartland, WI, USA) and photographed. The 14-year-old stored YCD and freshly prepared reaction mix both produced strong signals. We further investigated effects of stability of two reagents: 8-year-old AmpliTaq and 8-year-old deoxyribonucleotides (Boehringer Mannheim, Basel, Switzerland). Nucleotides and Taq p have a labeled shelf life of two years. Sexing bands were observed in gels from the reaction mix with 8-year-old deoxyribonucleotides, but no signals were observed with the use of 8-year-old AmpliTaq. These results suggest that Taq p is the most likely candidate to cause failure in stored PCR reaction mixes. As supplied, Taq p is liquid even when stored in the freezer. Our hypothesis is that because the Taq p was frozen solid in YCD instead of being kept in a liquid form, the denaturing of Taq p was prevented. We conclude that storage and transport of PCR reaction mix could become more convenient: ship on dry ice and transport to the field in a mobile freezer.

269 THE ENHANCEMENT OF THE SENSITIVITY OF A PCR-BASED AVIAN SEX DETERMINATION ASSAY

For over a decade it has been possible to externally sex monomorphic birds using PCR. A major drawback of the protocol developed by Richard Griffiths is that DNA from at least 20 000 cells is needed (Griffiths et al. 1996 Proc. Royal Soc. London B 263, 1249–1254). Our study attempted to decrease the number of cells required. A sequence within the chromobox-helicase-DNA-binding (CHD) gene, located on the sex chromosomes of all avian species, was amplified. The sequence lengths were 362 and 354 base pairs for the CHD-W and CHD-Z, respectively. The polyacrylamide gel electrophoresis (PAGE) purified primers used were 5´-TCTGCATCGCTAAATCCTTT-3´ and 5´-CTCCCAAGGATGAGRAAYTG-3´ (2.5 µm) (IDT, Inc., San Jose, CA, USA). All assays used Taq DNA polymerase (2.7 U) (M0273L, New England BioLabs, Ipswich, MA, USA) and deoxyribonucleotides (5 µm) (C01581, GenScript Corp, Piscataway, NJ, USA). Lymphocytes from chickens (Gallus domesticus) (10 cells/2 µL) were used as the DNA source for all experiments. Assays were run with positive and negative DNA controls. The DNA was replicated in a Corbett Rapid Thermocycler (Model FTS-IS, Corbett Research, Sydney, Australia) in 20 µL volumes with an annealing temperature of 48�C. All of the PCR products were separated using PAGE. An 8% gel (17:1, con- to bis-acrylamide) with 10 mm TRIS (pH 8) was formed in an agarose gel chamber (M12 Electrophoresis Unit, Edvotek, Bethesda, MD, USA) under Ar. The gel was placed in 10 mm TRIS (pH 8) in the electrophoresis apparatus and the PCR products were added to wells. The applied voltage was 200 and the duration was 2 h (PS500ST, Hoefer Scientific Instruments, San Francisco, CA, USA). The gel was stained for 30 min in 1.25 µm ethidium bromide in 100 mL of 10 mm TRIS (pH 8). Destaining was carried out over 45 min in 100 mL of H2O. The gel was viewed using a transilluminator (3–300, Fotodyne, Hartland, WI, USA) and photographed with an Olympus digital camera. An initial experiment established Griffiths' assay in our lab. Results were consistent with published data, albeit with the same troubling signal-to-noise problems. No signals were observed in assays with less than 20 000 cells. The next experiment compared the use of Griffiths' amplification buffer to a buffer we developed, Bart: 50 mm barbital, 1% dextran T-500, 50 mm KCl, 2.5 mm MgCl2, and 0.035% 2-mercaptoethanol. Signals were produced and a working assay was established with only 10 cells needed, significantly fewer cells than the 20 000 cells necessary for Griffiths' protocol. It was possible to increase the number of productive replication cycles from 35 to 45 without generation of noise. In fact, use of Bart eliminated primer-generated noise, leaving only sexing bands in the gel. Interestingly, when Bart was used with 20 000 cells, no signals were observed. Assays incorporating Bart were run in triplicate and signals were consistently observed. Reduction in the number of cells required for avian sex determination provides potential applications for the sexing of embryos or sexing from a single down feather. Our assay makes sex determination prior to hormonal treatment simple. We are currently replacing the use of the CHD gene with a conserved W-specific sequence.

Measles, mumps and rubella vaccine: current safety issues

The current state of knowledge regarding the safety of measles, mumps and rubella vaccine (MMR) is reviewed. Although there are known adverse reactions to the vaccine, the majority are relatively minor and have no long term consequences, and those that do have long term consequences are extremely rare. Contraindications, known adverse reactions that may follow MMR immunisation, publicised adverse events for which a causal association with MMR has not been established, and the complications that may follow an infection with wild-type measles, mumps or rubella, are discussed. The article also discusses, with examples, the misleading information that can be obtained on the internet and in the public press. It is vital that the general public have an understanding of the great benefits and low risks associated with the use of MMR vaccine, because it is important that they consent to the administration of MMR vaccine to their children in order to ensure the success of universal immunisation programmes and the control of measles, mumps and rubella. Therefore, it becomes increasingly important for health professionals to use innovative education methods to promote immunisation and counteract the incorrect and misleading information that is readily available on the internet and in the media.

Do clinical trials improve quality of care? A comparison of clinical processes and outcomes in patients in a clinical trial and similar patients outside a trial where both groups are managed according to a strict protocol

BACKGROUND

The conventional view that participants in randomised controlled trials sacrifice themselves for the good of future patients is challenged by increasing evidence to suggest that individual patients benefit from participation in trials.

OBJECTIVE

To test the hypothesis that trial participants receive higher quality care and, as a consequence, have better outcomes than patients receiving guideline driven routine care.

METHODS

Retrospective comparative study of 408 women with pre-eclampsia all managed according to a strict protocol. Trial participants were 86 women who participated in a multicentre randomised controlled trial of magnesium sulphate for the treatment of pre-eclampsia (Magpie Trial); 322 non-participants formed the control group. Indicators of the process of care and clinical outcomes were compared between the two groups.

RESULTS

Trial participants were significantly more likely to have received daily blood tests (odds ratio (OR) 6.82, 95% CI 1.62 to 28.72) and had their respiration rate measured hourly (OR 3.42, 95% CI 1.69 to 6.92) than control patients. There were no significant differences in other markers of clinical process and no significant difference in clinical outcomes.

CONCLUSION

This study shows minor differences in process markers and no difference in clinical outcomes between patients in a clinical trial and patients receiving protocol driven care. The benefits of improved clinical care that have previously been associated with being in a trial may be explained by the use of clear clinical protocols. In routine practice, patients may be well advised to insist on treatment as part of a protocol.

Vulnerability to smoking after trying a single cigarette can lie dormant for three years or more

OBJECTIVE

To examine the development of smoking behaviour among adolescents who, at age 11, had tried cigarettes just once.

DESIGN

A five-year prospective study.

SETTING

36 schools in South London, England.

SUBJECTS

A socioeconomically and ethnically diverse sample of students completed questionnaires annually from age 11-16. A total of 5863 students took part, with an annual response rate ranging from 74-85%. 2041 (35%) provided smoking status data every year.

MAIN OUTCOME MEASURES

Current smoking (smoking sometimes or more often) for the first time. Cotinine assays provided biochemical verification of smoking status.

RESULTS

Students who at age 11 reported having tried smoking cigarettes just once (n = 260), but were not smoking at the time, were more likely to take-up smoking at a later age than those that had not tried smoking (n = 1719), even after a gap of up to three years of not smoking. The odds of starting to smoke at age 14 were 2.1 times greater (95% confidence interval 1.2 to 3.5) in the age 11 "one time triers" than the "non-triers", even once sex, ethnicity, deprivation, parental smoking and conduct disorder were adjusted for.

CONCLUSIONS

This is the first clear demonstration of a "sleeper effect" or period of dormant vulnerability. Our findings have implications for understanding the development of cigarette use and for policies to reduce smoking in young people. Preventing children from trying even one cigarette may be important, and the design of interventions should recognise adolescents who have smoked just once, several years previously, as potentially vulnerable to later smoking uptake.