Molecular analysis of avian H7 influenza viruses circulating in Eurasia in 1999-2005: detection of multiple reassortant virus genotypes

Avian influenza infections by high and low pathogenicity H7 influenza viruses have caused several outbreaks in European poultry in recent years, also resulting in human infections. Although in some cases the source of H7 strains from domestic poultry was shown to be the viruses circulating in the wild bird reservoir, a thorough characterization of the entire genome of H7 viruses from both wild and domestic Eurasian birds, and their evolutionary relationships, has not been conducted. In our study, we have analysed low pathogenicity H7 influenza strains isolated from wild and domestic ducks in Italy and southern China and compared them with those from reared terrestrial poultry such as chicken and turkey. Phylogenetic analysis demonstrated that the H7 haemagglutinin genes were all closely related to each other, whereas the remaining genes could be divided into two or more phylogenetic groups. Almost each year different H7 reassortant viruses were identified and in at least two different years more than one H7 genotype co-circulated. A recent precursor in wild waterfowl was identified for most of the gene segments of terrestrial poultry viruses. Our data suggest that reassortment allows avian influenza viruses, in their natural reservoir, to increase their genetic diversity. In turn this might help avian influenza viruses colonize a wider range of hosts, including domestic poultry.

Evolutionary Analysis of HA and NS1 Genes of H5N1 Influenza Viruses in 2004–2005 Epidemics

H5N1 avian influenza viruses circulating in early 2004 in eastern Asia appeared to be under strong purifying selection, except for the hemagglutinin (HA) and nonstructural 1 (NS1) genes, where few amino acid positions were found under positive selection pressure. To evaluate whether the widespread circulation of the H5N1 viruses in the following years was accompanied by a change in the evolution of the HA and NS1, phylogenetic and positive selection analyses were performed on 89 HA and 57 NS1 sequences. Results showed that the number of HA positively selected sites decreased compared to 2004; no selection pressure for NS1 was found. These findings suggest a possible change in the adaptation of the H5N1 virus to birds.

Prevalence of antibodies against A and B influenza viruses in South-Western Papua New Guinea

Influenza viruses remain a major cause of respiratory disease in both developed and developing countries. Nevertheless, there is little information on the prevalence of this respiratory infection in many developing countries, such as Papua New Guinea, since most of the available data originate from studies carried out in industrialized countries. In the present study, a serosurvey among residents of 47 remote villages of Papua New Guinea was conducted to evaluate the intensity of exposure to human influenza A and B viruses. The data obtained confirm the co-circulation of these antigenic variants, reported having circulated in the Southern Hemisphere. Variations in seroprevalence of influenza A and B virus infection were found within the study area.

[Vaginal swab in pediatric age]

Vaginal secretion sampling in young patients. The aim of the study was to evaluate whether different instrumental tools (the classical cotton swab, the urethral cotton swab, the balloon shape cotton swab and cyto-brush) yield different sampling success in young patients presenting with suspected vulvovaginitis. The study was conducted in a randomised prospective way on 100 children with symptoms of vulvovaginal infection (age range: 4 months -8 years ) seen at the Clinic of Paediatric Gynaecology of the Department of Obstetric and Gynaecology, "V.Buzzi" Children's Hospital, Milano (Italy). Children's compliance and the number of samples which had to be discontinued, because of children's intolerance have allowed the evaluation of each tools. Each of these tools was tested on 25 young patients. The vaginal secretion sampling was not possible on 8 patients out of 25 with cyto-brush (32%), on 7 out of 25 with the balloon shape cotton swab (28%), on 4 out of 25 with the classical cotton swab (16%) and only 1 out of 25 with the urethral cotton swab (4%). In conclusion all the instruments tested allow sampling of vaginal secretion in young children, but the reaction and compliance of the patients has been best with the otologic cotton swab.

Smoking and weight control behaviors

OBJECTIVE

To examine the association between weight control and tobacco use in young women.

METHODS

Smoking status and weight and eating related issues, endorsement of the belief "smoking helps to control weight" dieting status (DEBQ-R), current and ideal weight and current height were assessed in 144 students.

RESULTS

Smoker (S) restrained eaters (RE) scored higher on dietary restraint than nonsmoker (NS) RE. In the smoking questionnaire, S-RE selected a significantly higher number of items concerning hunger, eating and weight than S unrestrained eaters (URE). S-RE had a greater level of endorsement of the belief: "smoking helps to control weight" than NS-URE. The subjects who marked those items had significantly higher scores in the DEBQ-R and were more likely to be RE than those who marked none of them.

CONCLUSION

Our findings suggest that among young women who smoke and diet there might be a risk group that smokes as a weight control strategy.

Interspecies transmission of an H7N3 influenza virus from wild birds to intensively reared domestic poultry in Italy

Since the "bird flu" incident in Hong Kong SAR in 1997, several studies have highlighted the substantial role of domestic birds, such as turkeys and chickens, in the ecology of influenza A viruses. Even if recent evidence suggests that chickens can maintain several influenza serotypes, avian influenza viruses (AIVs) circulating in domestic species are believed to be introduced each time from the wild bird reservoir. However, so far the direct precursor of influenza viruses from domestic birds has never been identified. In this report, we describe the antigenic and genetic characterization of the surface proteins of H7N3 viruses isolated from wild ducks in Italy in 2001 in comparison to H7N3 strains that circulated in Italian turkeys in 2002-2003. The wild and domestic avian strains appeared strictly related at both phenotypic and genetic level: homology percentages in seven of their genes were comprised between 99.8% (for PB2) and 99.1% (for M), and their NA genes differed mainly because of a 23-aminoacid deletion in the NA stalk. Outside this region of the molecule, the NAs of the two virus groups showed 99% similarity. These findings indicate that turkey H7N3 viruses were derived "in toto" from avian influenza strains circulating in wild waterfowl 1 year earlier, and represent an important step towards the comprehension of the mechanisms leading to interspecies transmission and emergence of potentially pandemic influenza viruses.

[Comprehensive treatment of obesity and its prevention]

Obesity is associated to chronic metabolic entities affecting the quality of life and life expectancy. An early treatment, if efficient, can overcome most of the problems. The normalisation of body composition, of energy reserves and their distribution, as well as the minimisation of weight dependent metabolic upsets and the establishment of therapeutic priorities, according to the repercussions of obesity, are important factors for the treatment of this disease. Prevention is important and its basis is teaching and the setting in healthy life style with modification of the food habits and the incorporation of physical work into everyday activities. Diet therapy, physical activity, pharmacotherapy, surgery education and psychology are the forms proposed for the treatment and prevention of obesity.

Characterization of the non-linear rate-dependency of QT interval in humans

AIMS

Repolarization has rate-dependent and rate-independent components. A function considering such components separately was validated in canine Purkinje fibres and applied to the QT/RR relation in humans.

METHODS AND RESULTS

Action potential duration (APD) was measured in Purkinje fibres during steady-state pacing at different cycle lengths (CL) and after prolonged quiescence (APD(0)). The APD/CL relationship was expressed by this function: APD=APD(max)(*)CL(S)/(CL(50)(S)+CL(S)), where APD(max) (APD extrapolated at infinite CL) is a rate-independent measure of repolarization, CL(50) (CL at which 50% of APD(max) is achieved) and S evaluates the rate dependency of APD. The same function was used to fit the QT/RR relation in 46 normal subjects (20 males, 26 females) and in 7 amiodarone-treated subjects undergoing a bicycle stress test. RR and QT (V(5)) were measured at the end of each load step; QT(c) (Bazett's formula) was obtained at rest. The APD/CL and QT/RR relations were equally well expressed by the function with high correlation coefficients (R>or=0.90). In Purkinje fibres, APD(max) was 461+/-37 ms, CL(50) was 394+/-54 ms and S was 0.98+/-0.11. APD(max) and APD(0) correlated (R=0.96) and were similar. The corresponding values in humans were: QT(max) 432+/-63 ms, RR(50) 345+/-60 ms and S 2.6+/-0.8. While QT(c) and QT(max) were longer in females, RR(50) and S were similar between genders. Amiodarone increased QT(c), QT(max) and RR(50) and decreased S. In QT(max) and QT(c) distributions generated by pooling data from treated and untreated subjects, 86% of treated subjects were correctly identified by QT(max) and 28% by QT(c).

CONCLUSIONS

Canine and human repolarization showed a saturating dependency on cycle length, described by the proposed function. Gender and amiodarone independently affected QT(max), RR(50) and S: therefore they might reflect specific ionic mechanisms. Finally, QT(max) identified drug-induced repolarization abnormalities in individual subjects better than QT(c).

Changes of autonomic cardiac profile after a 3-week integrated body weight reduction program in severely obese patients

The autonomic control of the heart is abnormal in obese subjects due to a prevalence of sympathetic over parasympathetic limb of the autonomic balance. We evaluated the effects of a short-term (3 weeks) integrated body weight reduction program (consisting of energy restricted diet and high-intensity exercise training) on heart rate variability (HRV) in severely obese, normotensive patients. The HRV was evaluated both in the time and frequency domain over a 18-hour Holter recording period obtained before and at the end of the third week. Three-week body weight reduction program reduced BMI (from 41.4 +/- 4.6 to 39.5 +/- 4.3 kg/m2, -4.6%, p<0.0001) and heart rate (from 77.8 +/- 8.6 to 73.6 +/- 8.7 b/min, p=0.0003). Significant changes in the autonomic profile were observed both in the time and frequency domain (SD of RR interval, SDRR: +16.1%; mean squared successive difference: (MSSD) +16.7%; percentage of RR intervals differing more than 50 msec from the preceding one, pNN50: +31.8%; low frequency oscillation, LF: +17.1%; high frequency oscillation, HF: +/- 18.2%). In conclusion, this study demonstrates that a short-term, integrated body weight reduction program is able to favorably modify the autonomic profile in a population of normotensive, severely obese subjects. The reduction of heart rate and the increase in parasympathetic activity may consistently contribute to a reduction of the risk of cardiovascular morbidity and of sudden cardiac death, still high in this patients' group.

[Antihypertensive therapy in the elderly: results of large trials]

The aim of this review was to evaluate if antihypertensive treatment in elderly hypertensive patients is able to lower the incidence of cardiovascular events when compared to hypertensive controls who received placebo. All trials agree in that the greater blood pressure reduction in hypertensive patients randomized to active treatment is associated with a minor incidence of cerebrovascular, cardiac and all cardiovascular events in comparison to placebo-treated control groups. Therefore the chronic antihypertensive treatment makes more good than bad. All antihypertensive agents have been used for the treatment of arterial hypertension in the elderly and all have shown a good efficacy and tolerability, even if, as in the adult hypertensives, the combination of two or more agents is necessary in the great majority of hypertensive patients to reach the target blood pressure. Because life expectancy is progressively longer and the prevalence of hypertension, in particular isolated systolic hypertension, is age-dependent, it is clinically relevant to investigate if there is an upper limit for the benefit of antihypertensive therapy. The results so far available suggest a benefit up to the age of 80 years, while an ongoing study is aimed at evaluating the benefit of antihypertensive therapy in patients > 80 years. Finally, according to our personal point of view, there are sufficient data to sustain the indication of a diastolic blood pressure reduction between 80 and 90 mmHg, while the indication to a reduction in systolic blood pressure below 140 mmHg is less strong and supported.