Ghost resonance in the chaotic Chua's circuit

We experimentally investigate the ghost resonance phenomenon in the electronic circuit of Chua operating in the chaotic regime. The circuit can be stimulated to jump between two single-scroll attractors by an external periodic signal with an amplitude above an intrinsic threshold. For subthreshold signals, jumps between the chaotic attractors can be promoted by a superposed white noise. We show that the circuit output can exhibit a well-defined ghost resonance signature, i.e., a resonance on a frequency that is absent in a multicomponent input signal, when the amplitudes of the input components are properly related. Further, we show that ghost resonance can be induced by the Chua's circuit's own chaotic dynamics when it is driven by a suprathreshold multicomponent signal without the need of an external noise source.

Effect of green tea (Camellia sinensis) consumption on the components of metabolic syndrome in elderly

OBJECTIVE

To evaluate the effect of the consumption of green tea on components of MS in the elderly.

DESIGN

Intervention study.

SETTING

The sample was selected from the Geriatric Service of Hospital São Lucas of Pontifical Catholic University of Rio Grande do Sul.

PARTICIPANTS

45 elderly with MS were enrolled and allocated into two groups: green tea group (GTG, n= 24), who drank green tea and control group (CG, n= 21) without intervention.

INTERVENTION

The GTG received sachets of 1.0 g of green tea, and should drink three cups per day for 60 days and the CG was instructed not to make changes in their lifestyle.

MEASUREMENTS

The diagnostic criteria for MS used were the International Diabetes Federation. The lipidic and glycemic profile, and anthropometric measurements were evaluated before and after intervention.

RESULTS

There was a statistically significant weight loss only in GTG [71.5±12.6 kg to 70.3±12.6 kg (p<0.001)]. A statistically significant decrease in BMI [-0.5±0.4 kg/m2 in GTG and -0.2±0.6 kg/m2 in CG (P=0.032)] and waist circumference [-2.2±2.0 cm in GTG and - 0.3±1.8 cm in CG (P=0.002)] were observed. The intake of green tea did not change the biochemical parameters.

CONCLUSION

The consumption of green tea was effective in inducing weight loss, reducing BMI and waist circumference in the elderly with MS.

Smoking habits in secondary school students

BACKGROUND

Smoking is an important health risk in general, and responsible for diseases with significant mortality and morbidity. Smoking habits start early and adolescence is a notorious time for starting smoking.

AIM AND METHODS

To assess knowledge on smoking and smoking habits in a population of adolescents in four Porto schools, using a confidential self administered questionnaire. Collected data were evaluated using the SPSS 1.2 statistics program (2004 version).

RESULTS

A total of 1,770 students aged 11 - 21 (median 15.1 years), mainly female, (58%), answered. Most students (n=952, 54.6%) were unaware of signs or warnings against smoking in their schools. The great majority (n=1639, 92.7%) considered themselves well informed on the harmful effects of smoking, but only 6.7% could list three or more tobacco-associated health consequences, however. Parents and friends were seen as privileged sources of information. Among these students, 194 (11.1%) were smokers and the average started to smoke at the age of 15. The majority of these (n=111, 57.2%) had parents who smoked and 96.4% had friends who smoked, versus 83.1% of non-smokers, a statistically significant difference (p < 0.001). Pocket money was the means of acquiring cigarettes in 34.8%. Most (60.8%) considered themselves able to stop smoking at any time, while 11.4% of the smokers smoked more than one pack a day and 9.8% smoked the first cigarette within 5 minutes of waking, however.

CONCLUSIONS

The percentage of smokers in this group of teenagers was considerable and indicators of nicotine dependence were found. Knowledge of the risks of smoking was poor and information on smoking given by schools had an apparently low and variable impact. Parents' and friends' behaviour may have a weighty impact on the decision to start smoking.

Nontuberculous mycobacteria in non-AIDS patients

Nontuberculous mycobacteria (NTM) play an increasingly significant pathogenic role in HIV -positive patients, in patients with chronic lung disease, in other chronic conditions and in the elderly.

AIMS

Evaluate the importance of NTM isolation in respiratory samples in patients without HIV-infection.

METHODS

Retrospective evaluation of our hospital patients with no known AIDS, with at least one NTM positive respiratory sample, from 1997 -2004.

RESULTS

We found 102 patients, with a median age of 63 years; 67% male. Sixty -three (62%) had underlying lung disease, mainly tuberculosis sequelae (n=19). The majority (47%) of the isolations were Mycobacterium avium complex (MAC). A diagnosis of Mycobacterium pulmonary disease was made in 16 patients (15.7%), 14 of which met the American Thoracic Society diagnostic criteria. Ten male and 6 female; median age 65 years. Twelve had underlying lung disease. All of them had respiratory infection complaints. Chest X -rays showed mainly pulmonary infiltrates, linear opacities and cavitation. MAC was the cause of mycobacterium respiratory disease in 12 patients (75%).

CONCLUSION

NTM isolation did not equal pulmonary NTM disease in the majority of cases, even in patients with underlying lung disease. MAC was the most commonly isolated agent and its relative importance was higher in the presence of NTM disease.

[Cystic fibrosis: review]

Cystic Fibrosis (CF) is the recessive autossomic disease more frequent in the caucasian race. The main characteristic is a mutation in CFTR, a trans-membranar protein, responsible for chlorates transportation. This protein has a diffuse epithelial distribution, which gives a multissistemic involvement to this disease, with clinical manifestations with variable degrees of severity. The development of better health care associated with new therapeutic options became responsible for an increase of survival, so CF is no longer a paediatric disease. Lung transplantation also has an important role, bringing new treatment perspectives. So, this pathology has an increased multi-disciplinary involvement in which the pulmonologist have a preponderant role.

Genetic data of 10 X-STRs in a Spanish population sample

In this work, we present population genetic data of 10 X-chromosome STRs (DXS8378, DXS9898, DXS8377, HPRTB, GATA172D05, DXS7423, DXS6809, DXS7132, DXS101 and DXS6789) obtained from sample of 145 unrelated female individuals belonging to Valencia (Spain), a region located in the east of the Iberian Peninsula. All the markers studied present high genetic diversities, similar to those previously reported in other European population samples. No deviations from Hardy-Weinberg equilibrium were observed, with the exception of DXS101 locus. Allele frequencies and parameters of forensic interest for each X-STR were calculated. High mean exclusion chance and power of discrimination values were obtained by combining these 10 X-linked markers. Population comparisons (exact test of population differentiation; pairwise genetic distances) were carried out and low genetic distances were found between our sample and those from other Spanish or European regions.

Modifications of the sympathetic skin response in workers chronically exposed to lead

The long-term effects of low-level lead intoxication are not known. The sympathetic skin response (SSR) was evaluated in a group of 60 former workers of a primary lead smelter, located in Santo Amaro, BA, Brazil. The individuals participating in the study were submitted to a clinical-epidemiological evaluation including questions related to potential risk factors for intoxication, complaints related to peripheral nervous system (PNS) involvement, neurological clinical examination, and also to electromyography and nerve conduction studies and SSR evaluation. The sample consisted of 57 men and 3 women aged 34 to 69 years (mean +/- SD: 46.8 +/- 6.9). The neurophysiologic evaluation showed the presence of lumbosacral radiculopathy in one of the individuals (1.7%), axonal sensorimotor polyneuropathy in 2 (3.3%), and carpal tunnel syndrome in 6 (10%). SSR was abnormal or absent in 12 cases, representing 20% of the sample. More than half of the subjects (53.3%) reported a history of acute abdominal pain requiring hospitalization during the period of work at the plant. A history of acute palsy of radial and peroneal nerves was reported by about 16.7 and 8.3% of the individuals, respectively. Mean SSR amplitude did not differ significantly between patients presenting or not the various characteristics in the current neurological situation, except for diaphoresis. The results suggest that chronic lead intoxication induces PNS damage, particularly affecting unmyelinated small fibers. Further systematic study is needed to more precisely define the role of lead in inducing PNS injury.

[Cystic fibrosis in adults]

The authors reviewed adult cystic fibrosis patients followed in the Pulmonology Unit from 1994-2004 (n=8), five female and three male, aged 20-34 years old (median= 27 years). Patients were diagnosed at 18 months - 31 years old by sweat testing (positive in six patients) and genotyping (four patients homozygous for Delta F508 mutation). Respiratory involvement was characterised by sinusitis and bronchiectasis. Pulmonary involvement was accompanied by functional abnormalities and gas exchange impairment in the majority of the patients. Bronchial tree was colonised permanently in five patients: Pseudomonas aeruginosa in four and Staphilococcus aureus in four (three patients affected by both agents simultaneously). The main causes of exacerbation were respiratory infections and haemoptysis. Non-respiratory involvement was variable. Four patients had digestive involvement (one with hepatic cirrhosis), one had renal failure and only one had a sperm count to document infertility. Four patients had osteopaenia. Treatment included chest physiotherapy, bronchodilators, dornase alfa, mucolytics, digestive enzymes, vitamins, antibiotics and oxygen therapy. At review, one had left follow-up, one had died, one was awaiting lung transplant and the others evidenced no difference in clinical characteristics. In this group of patients the severity of the pulmonary disease was not related to a late diagnosis. It can be explained by the diversity of cystic fibrosis presentation in adults.

Improvement of sympathetic skin responses under enzyme replacement therapy in Fabry disease

AIM

To report the effect of enzyme replacement therapy (ERT) in sympathetic skin responses (SSR) of patients with Fabry disease.

PATIENTS AND METHODS

Seven male patients were included in an open-label protocol using agalsidase-alfa, continued at regular intervals. Five patients completed 24 months of ERT and two of them completed 18 months. Two main measurements were performed at baseline, as well as 1 and 2 years after ERT: (1) a standard neurological examination (NE), with a detailed evaluation of the sensory perception of light touch, pinprick, cold, hot, and vibratory stimuli; (2) the SSR amplitudes.

RESULTS

Although there were no significant differences between NE in this time period, all patients reported general improvement in their subjective reports of acroparaesthesia and sweating. Before starting ERT, the SSR amplitudes were either too small (3/7 patients) or absent (4/7 patients): the average (range) amplitude of 122 microV (0 through 492) was statistically smaller than that found in a control group, i.e. 1453.6 microV (619.7-2754) (p<0.0001, t-test). Mean +/- SD SSR amplitude increased to 1088+/- 690 microV in the second year of ERT, reaching the range found in a normal control group (p=0.004).

CONCLUSION

ERT improved SSR continuously in Fabry patients in 2 years of observation. Although the mechanism of the SSR improvement is unknown, this response to ERT can be clinically significant if it reflects a normalization in sweating.

Mutation rates at Y chromosome specific microsatellites

A collaborative work was carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG) to estimate Y-STR mutation rates. Seventeen Y chromosome STR loci (DYS19, DYS385, DYS389I and II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460, DYS461, DYS635 [GATA C4], GATA H4, and GATA A10) were analyzed in a sample of 3,026 father/son pairs. Among 27,029 allele transfers, 54 mutations were observed, with an overall mutation rate across the 17 loci of 1.998 x 10(-3) (95% CI, 1.501 x 10(-3) to 2.606 x 10(-3)). With just one exception, all of the mutations were single-step, and they were observed only once per gametogenesis. Repeat gains were more frequent than losses, longer alleles were found to be more mutable, and the mutation rate seemed to increase with the father's age. Hum Mutat 26(6), 520-528, 2005. (c) 2005 Wiley-Liss, Inc.

Functional interactions between mu opioid and alpha 2A-adrenergic receptors

Adrenergic and opioid receptors belong to the rhodopsin family of G-protein coupled receptors, couple to analogous signal transduction pathways, and affect the nociceptive system. Although a number of previous studies have reported functional interactions between these two receptors, the basis for this has not been well explored. We propose that direct receptor-receptor interactions could account, in part, for opioid-adrenergic cross-talk. In this report, we have addressed this using biophysical, biochemical, and pharmacological studies. We show that mu opioid and alpha2A adrenergic receptors reside in close proximity in live cells using the bioluminescence resonance energy transfer assay. These receptors colocalize to proximal dendrites in primary hippocampal neurons. mu-alpha2A Receptor complexes can be isolated from heterologous cells or primary neurons coexpressing these receptors. In these cells, the activation of either mu or alpha2A receptor leads to a significant increase in the level of immunoprecipitable mu-alpha2A complexes, whereas activation of both receptors leads to a significant decrease. The implications of these effects on signaling were examined using the agonist-mediated increase in G-protein activity and mitogen-activated protein kinase activity. We find that activation of either mu or alpha2A receptors leads to an increase in the extent of signaling, whereas activation of both receptors leads to a decrease. The increase in signaling by individual ligands and decrease by a combination of ligands is also seen in primary spinal cord neurons endogenously expressing these receptors. Taken together, these results suggest that physical associations between mu and alpha2A receptors could play a role in the functional interactions between these receptors.

Highly thermostable amylase and pullulanase of the extreme thermophilic eubacterium Rhodothermus marinus: production and partial characterization

Five strains of the extreme thermophilic Rhodothermus marinus were screened for the production of amylolytic and pullulytic activities. The culture medium for the selected strain, R. marinus ITI 990, was optimized using central composite designs for enhanced enzyme production. The optimized medium containing 1.5 gl(-1) of maltose and 8.3 gl(-1) of yeast extract yielded amylase, pullulanase and alpha-glucosidase activities of 45, 33 and 2.1 nkatml(-1), respectively. Among the various carbon sources tested, maltose was most effective for the formation of these enzymes, followed by soluble maize starch, glycogen and pullulan. The crude amylase and pullulanase showed maximum activities at pH 6.5-7.0, and 85 and 80 degrees C, respectively. At 85 degrees C amylase and pullulanase had half lives of 3 h and 30 min, respectively.

G-protein-coupled receptor dimerization: modulation of receptor function

G-protein-coupled receptors (GPCRs) comprise the largest family of transmembrane receptors in the human genome that respond to a plethora of signals, including neurotransmitters, peptide hormones, and odorants, to name a few. They couple to second messenger signaling cascade mechanisms via heterotrimeric G-proteins. Recently, many studies have revealed that GPCRs exist as dimers, which may be present as homo- or heterodimers/oligomers. These recent findings have been met with skepticism, since they are contradictory to the dogma that GPCRs function as monomers. Although the existence of GPCR dimers/oligomers was predicted from early pharmacological and biochemical studies, further studies to critically evaluate this phenomenon were impeded by the lack of appropriate reagents. The availability of cDNAs for GPCRs, of highly selective ligands and of antibodies for these receptors has made it possible to visualize and investigate the functional effects of GPCR oligomers. Pharmacological studies, along with biochemical techniques, such as cross-linking and immunoprecipitation with differentially epitope-tagged receptors, have been employed to demonstrate the oligomerization of a number of GPCRs. Moreover, recent biophysical techniques, such as bioluminescence and fluorescence resonance energy transfer, now make it possible to examine GPCR dimerization/oligomerization in living cells. In this review, we provide a brief overview of some of the techniques employed to describe GPCR dimers, and we discuss their respective limitations. We also examine the implications of dimerization/oligomerization on GPCR function. In addition, we discuss domains of the receptors that are thought to facilitate dimerization/oligomerization. Finally, we consider recent evidence for the subcellular localization of the dimer/oligomer assembly.

A novel nuclear protein, 5qNCA (LOC51780) is a candidate for the myeloid leukemia tumor suppressor gene on chromosome 5 band q31

Interstitial deletion or loss of chromosome 5, del(5q) or -5, is a frequent finding in myeloid leukemias and myelodysplasias, suggesting the presence of a tumor suppressor gene within the deleted region. In our search for this gene, we identified a candidate, 5qNCA (LOC51780), which lies within a consistently-deleted segment of 5q31. 5qNCA expresses a 7.2-kb transcript with a 5286-bp open reading frame which is present at high levels in heart, skeletal muscle, kidney, placenta, and liver as well as CD34+ cells and AML cell lines. 5qNCA encodes a 191-kD nuclear protein which contains a highly-conserved C-terminus containing a zinc finger with the unique spacing Cys-X2-Cys-X7-His-X2-Cys-X2-Cys-X4-Cys-X2-Cys and a jmjC domain, which is often found in proteins that regulate chromatin remodeling. Expression of 5qNCA in a del(5q) cell line results in suppression of clonogenic growth. Preliminary sequence results in AML and MDS samples and cell lines has revealed a possible mutation in the KG-1 cell line resulting in a THR to ALA substitution that has not been found in over 100 normal alleles to date. We propose 5qNCA is a good candidate for the del(5q) tumor suppressor gene based on its predicted function and growth suppressive activities, and suggest that further mutational and functional study of this interesting gene is warranted.