Beta-haemolytic streptococci in school children 5-15 years of age with an emphasis on rheumatic fever, in the tri-island state of Grenada

The objective of this study is to determine the prevalence of beta-haemolytic streptococci in the pharynx and antibodies to beta-haemolytic streptococci in school children 5-15 years of age in the tri-island state of Grenada Blood samples and throat swabs were obtained from 1388 school children, aged 5-15 years old attending randomly selected schools in each parish of the tri-island state of Grenada. Serum samples were subjected to antistreptolysin o testing (ASOT) while throat swabs were cultured on sheep blood agar plates. The prevalence of positive throat swab was 15.4% (95% CI = 13.4%, 17.2%). The rate was highest in St Patrick (21.8%) and lowest in Carriacou (5.7%). The prevalence of antibodies was 38.6% (95% CI = 37.6%, 42.8%). It was highest in St Patrick (54.4%) and lowest in Petit Martinique (26.8%). In St Patrick, males were significantly more likely than females to have a positive ASOT (p = 0.0084). In St George's, males were significantly more likely than females to have a positive throat culture (p = 0.0172). Thirty-four per cent of the positive cultures were type A, 10% were type C and 56% type G. The data illustrate that there is a high prevalence of beta-haemolytic streptococci in school children in certain parishes in Grenada. Public health measures should address prevention and control of beta3-haemolytic streptococcal infection in order to prevent the possible sequelae of this disease.     

Prevention of experimental allergic encephalitis in guinea-pigs with spinal cord protein: optimum pretreatment schedules and appraisal of plausible mechanisms.

Pretreatment of Hartley guinea-pigs with three injections of 100 microgram of the purified bovine spinal cord protein, (SCP), protected tham from clinical experimental allergic encephalitis (EAE) when they were subsequently challenged with 50 microgram of purified bovine myelin basic protein (MyBP) in Freund's complete adjuvant (FCA). The length of the optimum pretreated schedule was found to be 1 week and the animals were fully protected for 2 weeks. Protection declined thereafter so that by 4 weeks following pretreatment only 40% of the animals were protected. The protected state could be restored several weeks after it had lapsed by repeating the treatment with SCP. Immature animals did not respond well to pretreatment with SCP. Evidence was presented to indicate that specific, non-specific immune suppression or anti-SCP IgG were not involved to a significant extent in protection. SCP-treated guinea-pigs regularly displayed delayed skin hypersensitivity to MyBP after sensitization but there was no correlation between the degree of cutaneous reactivity and protection from disease. Because SCP is localized in the nerve axon, the speculation was advanced that anti-SCP blocking factors might be responsible for preserving axonal function in SCP-treated animals sensitized with MyBP.     

Correlation between angiographic findings and the ischaemia of head injury.

The carotid angiograms of 96 patients who had died from non-missile head injury were reviewed and assessed for evidence of arterial spasm, slowing of the cerebral circulation, and the presence of intracranial haemotoma. As bilateral angiography had been done in 44 cases the results are based on a correlation between the angiographic appearances and the presence or absence of ischaemic brain damage in the cortex of 140 cerebral hemispheres. There was a significant relationship between spasm alone, the presence of intracranial haematoma alone, or their combination, and ischaemic damage in the ipsilateral cortex. Apart from an association between the more severe grades of spasm and slowing of circulation in the group with ischaemia within arterial territories, there was none between slowing of the circulation or the combination of slowing with either spasm or haematoma and ischaemic brain damage.     

Predicting in vitro tissue culture growth for cytogenetic evaluation of stillborn fetuses

A prospective study was undertaken of 131 perinatal deaths to determine whether gestational age, body weight, maceration degree and autopsy interval influenced successful in vitro tissue culture for cytogenetic evaluation. Perinatal populations were categorized as neonatal death (NND), fresh stillbirth (FSB), or graded as macerated stillbirth (MAC-0, MAC-1, MAC-2, MAC-3). Metaphase production by at least 15 cells separated 'growth' from 'no growth' categories after sampling liver, kidney and spleen. Body weight and degree of maceration were predictive of successful 'growth', while gestational age and autopsy interval were not. Body weight was significant in separating 'growth' from 'no growth' in NND (P = 0.05), FSB, MAC-0 and MAC-1 (P = 0.01). Growth probabilities were 0.78 (NND), 0.57 (FSB), 0.49 (MAC-0), 0.38 (MAC-1) and zero for MAC-2 and MAC-3. We conclude that (a) tissues from MAC-2 and MAC-3 fetuses do not grow and thus need not be sampled at autopsy, (b) maceration degree and body weight can be used to predict the growth probability in the other categories, (c) tissue samples can be taken during daylight hours, since autopsy interval does not influence successful growth provided the fetus is refrigerated at 4 degrees C, (d) all of the above conclusions have cost-efficiency implications for cytogenetic laboratories.     

Is early-pregnancy proteinuria associated with an increased rate of preeclampsia in women with pregestational diabetes mellitus?

OBJECTIVE: The purpose of this study was to determine whether the rate of preeclampsia in pregnant diabetic women is increased in those women with early-pregnancy proteinuria of 190 to 499 mg/24 hours compared with women with proteinuria of <190 mg/24 hours. STUDY DESIGN: Secondary analysis was performed with relevant data from 194 pregnant women with type 1 and type 2 diabetes mellitus whose condition required insulin and who were enrolled previously in a multicenter trial of low-dose aspirin for the prevention of preeclampsia. The women were assigned to 1 of 3 groups, based on the level of proteinuria at enrollment (13-26 weeks of gestation). Group 1 comprised women with <190 mg protein/24 hours (n=94); group 2 comprised women with 190 to 499 mg protein/24 hours (n=35); and group 3 comprised women with >/=500 mg protein/24 hours (n=65). The rate of preeclampsia, according to strict predefined criteria, was then determined. RESULTS: The rate of preeclampsia was not increased statistically significantly in patients with early-pregnancy proteinuria of 190 to 499 mg/24 hours (7/35 women; 20%) when compared with women with proteinuria of <190 mg/24 hours (16/94 women; 17%). CONCLUSION: We did not find an increased rate of preeclampsia in women with pregestational diabetes mellitus with early-pregnancy proteinuria of 190 to 499 mg/24 hours when compared with women with pregestational diabetes mellitus with proteinuria of <190 mg/24 hours.     

Frequency of uterine contractions in asymptomatic pregnant women with or without a short cervix on transvaginal ultrasound scan

OBJECTIVE: The purpose of this study was to compare the frequency of uterine contractions in asymptomatic pregnant women with and without a short cervix (< 25 mm) on transvaginal ultrasound (TVU) and to determine the additive risk of contractions on the risk of preterm birth. STUDY DESIGN: The study involved secondary analysis of a blinded observational study of asymptomatic singleton pregnancies who were at high risk for preterm birth and who received both home uterine activity monitoring daily and transvaginal ultrasound of the cervix at 22 to 24 and 27 to 28 weeks of gestation. Thresholds for the maximum frequency of uterine contractions of 4 per hour and transvaginal ultrasound cervical length of 25 mm were used for analysis. Contraction frequency was compared in women with cervical length < 25 mm and > or =25 mm and was correlated with the risk of spontaneous preterm birth at < 35 weeks of gestation. RESULTS: Of the 303 women whose pregnancy was evaluated at 22 to 24 weeks of gestation, the 39 women (13%) with a cervical length of < 25 mm had 1.6 +/- 2.7 versus 1.2 +/- 2.0 contractions per hour in the 264 women (87%) with a cervical length of > or =25 mm (P=.37). At 27 to 28 weeks of gestation (n=295 women), contraction frequency was 3.2 +/- 3.7 versus 2.8 +/- 3.1 contractions per hour in women with a cervical length of < 25 mm (n=59 women; 20%) versus those with a cervical length of > or =25 mm (n=236 women; 80%; P=.34). Among women with a short cervix, the relative risks for spontaneous preterm birth were 2.0 (95% CI, 0.95-4.2) and 2.1 (95% CI, 1.06-4.3) for women with > or =4 contractions per hour compared with women with < 4 contractions per hour at 22 to 24 and 27 to 28 weeks of gestation, respectively. Results were confirmed by logistic regression analysis. CONCLUSION: The frequency of uterine contractions in asymptomatic women was not related significantly to cervical length of < 25 mm versus > or =25 mm. Among women with a cervical length of < 25 mm at 22 to 24 or 27 to 28 weeks of gestation, there was a trend toward a 2-fold increased risk of spontaneous preterm birth when the maximum contraction frequency was > or =4 per hour, compared to < 4 per hour.     

A Spatially Explicit Nanomechanical Model of the Half-Sarcomere: Myofilament Compliance Affects Ca2+-Activation

The force exerted by skeletal muscle is modulated by compliance of tissues to which it is connected. Force of the muscle sarcomere is modulated by compliance of the myofilaments. We tested the hypothesis that myofilament compliance influences Ca2+ regulation of muscle by constructing a computational model of the muscle half sarcomere that includes compliance of the filaments as a variable. The biomechanical model consists of three half-filaments of myosin and 13 thin filaments. Initial spacing of motor domains of myosin on thick filaments and myosin-binding sites on thin filaments was taken to be that measured experimentally in unstrained filaments. Monte-Carlo simulations were used to determine transitions around a three-state cycle for each cross-bridge and between two-states for each thin filament regulatory unit. This multifilament model exhibited less "tuning" of maximum force than an earlier two-filament model. Significantly, both the apparent Ca(2+)-sensitivity and cooperativity of activation of steady-state isometric force were modulated by myofilament compliance. Activation-dependence of the kinetics of tension development was also modulated by filament compliance. Tuning in the full myofilament lattice appears to be more significant at submaximal levels of thin filament activation.     

A randomised controlled trial to determine the effect on response of including a lottery incentive in health surveys [ISRCTN32203485]

Background

Postal questionnaires are an economical and simple method of data collection for research purposes but are subject to non-response bias. Several studies have explored the effect of monetary and non-monetary incentives on response. Recent meta-analyses conclude that financial incentives are an effective way of increasing response rates. However, large surveys rarely have the resources to reward individual participants. Three previous papers report on the effectiveness of lottery incentives with contradictory results. This study aimed to determine the effect of including a lottery-style incentive on response rates to a postal health survey.

Methods

Randomised controlled trial. Setting: North and West Birmingham. 8,645 patients aged 18 or over randomly selected from registers of eight general practices (family physician practices). Intervention: Inclusion of a flyer and letter with a health questionnaire informing patients that returned questionnaires would be entered into a lottery-style draw for £100 of gift vouchers. Control: Health questionnaire accompanied only by standard letter of explanation. Main outcome measures: Response rate and completion rate to questionnaire.

Results

5,209 individuals responded with identical rates in both groups (62.1%). Practice, patient age, sex and Townsend score (a postcode based deprivation measure) were identified as predictive of response, with higher response related to older age, being female and living in an area with a lower Townsend score (less deprived).

Conclusion

This RCT, using a large community based sample, found that the offer of entry into a lottery style draw for £100 of High Street vouchers has no effect on response rates to a postal health questionnaire.