Towards a Unified Theory of Health-Disease: I. Health as a complex model-object

Theory building is one of the most crucial challenges faced by basic, clinical and population research, which form the scientific foundations of health practices in contemporary societies. The objective of the study is to propose a Unified Theory of Health-Disease as a conceptual tool for modeling health-disease-care in the light of complexity approaches. With this aim, the epistemological basis of theoretical work in the health field and concepts related to complexity theory as concerned to health problems are discussed. Secondly, the concepts of model-object, multi-planes of occurrence, modes of health and disease-illness-sickness complex are introduced and integrated into a unified theoretical framework. Finally, in the light of recent epistemological developments, the concept of Health-Disease-Care Integrals is updated as a complex reference object fit for modeling health-related processes and phenomena.

HIV risk practices by female sex workers according to workplace

OBJECTIVE To investigate differences in HIV infection- related risk practices by Female Sex Workers according to workplace and the effects of homophily on estimating HIV prevalence. METHODS Data from 2,523 women, recruited using Respondent-Driven Sampling, were used for the study carried out in 10 Brazilian cities in 2008-2009. The study included female sex workers aged 18 and over. The questionnaire was completed by the subjects and included questions on characteristics of professional activity, sexual practices, use of drugs, HIV testing, and access to health services. HIV quick tests were conducted. The participants were classified in two groups according to place of work: on the street or indoor venues, like nightclubs and saunas. To compare variable distributions by place of work, we used Chi-square homogeneity tests, taking into consideration unequal selection probabilities as well as the structure of dependence between observations. We tested the effect of homophily by workplace on estimated HIV prevalence. RESULTS The highest HIV risk practices were associated with: working on the streets, lower socioeconomic status, low regular smear test coverage, higher levels of crack use and higher levels of syphilis serological scars as well as higher prevalence of HIV infection. The effect of homophily was higher among sex workers in indoor venues. However, it did not affect the estimated prevalence of HIV, even after using a post-stratification by workplace procedure. CONCLUSIONS The findings suggest that strategies should focus on extending access to, and utilization of, health services. Prevention policies should be specifically aimed at street workers. Regarding the application of Respondent-Driven Sampling, the sample should be sufficient to estimate transition probabilities, as the network develops more quickly among sex workers in indoor venues.

Radiometric studies on the oxidation of (1-14c) fatty acids by drug-susceptible and drug-resistant mycobacteria

A radiometric assay system has been used to study oxidation patterns of (1-14C) fatty acids by drug-susceptible and drug-resistant organisms of the genus Mycobacterium. Two strains of M. tuberculosis susceptible to all drugs, H37Rv and Erdman, were used. Drug-resistant organisms included in this investigation were M. tuberculosis H37Rv resistant to 5 ug/ml isoniazid, M. bovis, M. avium, M. intracellular, M. kansasii and M. chelonei. The organisms were inoculated in sterile reaction vials containing liquid 7H9 medium, 10% ADC enrichment and 1.0 uCi of one of the (1-14C) fatty acids (butyric, hexánoic, octanoic, decanoic, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic). Vials were incubated at 37°C and the 14CO2 envolved was measured daily for 3 days with a Bactec R-301 instrument. Although each individual organism displayed a different pattern of fatty oxidation, these patterns were not distinctive enough for identification of the organism. No combination of fatty acids nor preferential oxidation of long chain or of short chain fatty acids were able to separate susceptible from resistant organisms. Further investigation with a larger number of drug susceptible mycobacteria including assimilation studies and oxidation of other substrates may be required to achieve a distinction between drug-susceptible and drug-resistant mycobacteria.

Radiometric studies on the oxidation of (U-14C) L-amino acids by drug-susceptible and drug-resistant mycobacteria

A radiometric assay system has been used to study oxidation patterns of (U-14C) L-amino acids by drug-susceptible and drug-resistant mycobacteria. Drug-susceptible M. tuberculosis (H37Rv TMC 102 and Erdman) along with the drug-resistant organism M. tuberculosis (H37 Rv TMC 303), M. bovis, M. avium, M. intracellulare, M. kansasii and M. chelonei were used. The organisms were inoculated into a sterile reaction system with liquid 7H9 medium and one of the (U-14C) L-amino acids. Each organism displayed a different pattern of amino acid oxidation, but these patterns were not distinctive enough for identification of the organism. Complex amino acids such as proline, phenylalanine and tyrosine were of no use in identification of mycobacteria, since virtually all organisms failed to oxidize them. There was no combination of substrates able to separate susceptible from resistant organisms.

Leishmania (Viannia) panamensis - induced cutaneous leishmaniasis in susceptible and resistant mouse strains

We studied the susceptibility to Leishmania (Viannia) panamensis in strains of mice. The C57BL/6 strain was resistant and showed self-controlled lesion at the injected foot pad. The BALB/c and DBA/2J strains were susceptible and showed a foot swelling that started day 20 post-infection and progressed to a tumour-like lesion in later period of observation. The CBA/HJ strain was found to be of intermediary resistance. In contrast to other known cutaneous leishmaniasis in mice, the lesion in L. (V.) panamensis-infected mice was restricted to the inoculation site in the skin. In addition, we studied the development of cellular response and antibodies against Leishmania antigen in BALB/c and C57BL/6 strains. The proliferative response of lymph node cells against L. (V.) panamensis antigen was biphasic in both strains. An initial response was seen on day 20, followed by a refractory period between 40 and 80 days and a second response around fourth month post-infection. The response in the latter period was higher in C57BL/6 strain than in BALB/c strain. BALB/c strain presented much higher anti-Leishmania antibody level than C57BL/6 strain. The model and the correlation of immunological variables and the course of the infection are discussed.

QUANTIFICATION OF THE POPULATION AND PHAGOCYTARY ACTIVITY OF HEMOCYTES OF RESISTANT AND SUSCEPTIBLE STRAINS OF Biomphalaria glabrata AND Biomphalaria tenagophila INFECTED WITH Schistosoma mansoni

Among the determinant factors in the resistance and susceptibility of Biomphalaria to Schistosoma mansoni, hemocytes play an important role. Aiming at studying S. mansoni/Biomphalaria interactions related to hemocytes, the first step is certainly connected with the standardization of this cell population in uninfected Biomphalaria. In this way, quantification of this cell population in hemolymph, as well as its phagocitary capacity, have been determined for the first time. Furthermore, using susceptible and resistant strains of B. glabrata and B. tenagophila, the hemocytegram and phagocytary capacity of hemocytes after infection with S. mansoni were determined too. Resistant and susceptible strains of B.glabrata (BA and BH, respectively), as well as resistant and susceptible strains of B. tenagophila (Taim and CF, respectively) were infected with 10 miracidia of the LE and SJ strains of S. mansoni, respectively. These infected snails and respective uninfected controls were assessed in relation to the number of circulating hemocytes and alteration in the phagocytary capacity, by using Zymozan and MTT. Reading was taken by means of a spectrophotometer at 5 hours and 1,2,5,10,20 and 30 days after infection. The results showed a decrease in population of the circulating phagocytary cells, 5 hours after infection. One day post-infection, the circulating cells of the susceptible snails showed an increased metabolic activity, but the same event could not be observed in the resistant strains. In the subsequent observation periods, significant differences among the strains studied could not be observed until the end of the experiment

In vitro evaluation of erythromycin in chloroquine resistant brazilian P. falciparum freshly isolates: modulating effect and antimalarial activity evidence

Erythromycin, a reversal agent in multidrug-resistant cancer, was assayed in chloroquine resistance modulation. The in vitro microtechnique for drug susceptibility was employed using two freshly isolates of Plasmodium falciparum from North of Brazil. The antimalarial effect of the drug was confirmed, with an IC50 estimates near the usual antimicrobial therapy concentration, and a significant statistical modulating action was observed for one isolate.

The perception, beliefs and practices toward genitourinary schistosomiasis by inhabitants of selected endemic areas (Edo/Delta States) in south-eastern Nigeria

Well-structured questionnaire on the perception, impression and response to genitourinary bilharziasis (Genitourinary schistosomiasis) was administered and explained in local languages: 'Igbo' 'Esan' 'Ezon' Itshekiri and Bini to 33815 inhabitants of selected endemic areas in south-eastern Nigeria from January, 1999 to December, 2001. Out of this number, 3815 (11.3%) were properly filled and returned. About 42.0% of the inhabitants admitted knowledge of the disease, while 14 (0.4%) knew about the aetiologic agent. About 181 (5.0%) who responded, admitted procuring treatment, while 100 (5.0%) declined to seek treatment of any sort. The relationships between water-bodies and human activities, and infection were well discussed. Amongst those who admitted knowledge of the disease but no knowledge of its etiologic agent, declined seeking treatment of any kind, but believe the disease is a natural phenomenon in ones developmental stage and therefore of no morbidity and mortality. Laboratory analysis of urine, faeces, semen and HVS was employed to assess questionnaire responses, and in some cases, physical examination was utilized to augment laboratory analysis in confirming urinal diagnosis. Haematuria was only directly related to egg count in the early part of life. Females were significantly haematuric and excreted more ova than males (p < 0.05). Headache (43.0%) and fever (31.0%) were major clinical signs while sexual pains (22.0%) were the least.

Staphylococcus aureus ampicillin-resistant from the odontological clinic environment

The aim of this research was to evaluate the prevalence of Sthaphylococcus spp. and S. aureus in the odontological clinic environment (air), their production of beta-lactamase and antibacterial susceptibility to the major antibiotics utilized in medical particle. During 12 months of samples collect were isolated 9775 CFU by MSA medium suggesting a high amount of Staphylococcus spp. in the clinic environment which can appear through aerosols. A total of 3149 colonies (32.2%) were suggestive of pathogenic staphylococci. Gram coloration, catalase test, colony-mallow growing on chromogenic medium, and coagulase test confirmed the identity of 44 (0.45%) S. aureus isolates. Of these, 35 isolates (79.5%) showed production of beta-lactamase by CefinaseTM discs and resistance to ampicillin, erythromycin (7 isolates) and tetracycline (1 isolate) suggesting the existence of multiresistant isolates. The evaluation of the oxacillin MIC by Etest® assays showed susceptibility patterns suggesting the inexistence of the mecA gene in chromosomal DNA. These results point out to the need of a larger knowledge on the contamination means and propagation of this microorganism into the odontological clinic.

Clonal types and antimicrobial resistance profiles of methicillin-resistant Staphylococcus aureus isolates from hospitals in south Brazil

In the present study were evaluated the DNA macrorestriction profile and SCCmec types for nine multi-resistant MRSA selected. Also antimicrobial susceptibility testing by disk diffusion method was evaluated for 68 MRSA isolates against 12 antimicrobial agents. The isolates were recovered from blood culture collected from hospitalized patients in three hospitals of Porto Alegre, Brazil. PFGE and PCR for mecA and SCCmec I, II, III, IV types genes were done on selected nine isolates with susceptibility only to vancomycin, teicoplanin and linezolid. Two clone profiles, with five subtypes, were demonstrated among multi-resistant MRSA analyzed. Eight isolates showed harbor SCCmec type III and one isolate was not typeable. The knowledge of SCCmec type, clone and antimicrobial profiles among S. aureus is essential mainly to prevention and control of dissemination of the antimicrobial resistance.

Molecular characterization of vancomycin-resistant Enterococci strains eight years apart from its first isolation in São Paulo, Brazil

E. faecium was the first reported VRE species, carrying the vanA gene in Brazil. In spite of this, vancomycin-resistant E. faecalis has become the predominant species in Brazilian hospitals. The aim of this study was to evaluate the genetic relatedness of VREs isolated in a Brazilian teaching hospital eight years apart from its first isolation. We analyzed 38 VRE strains obtained from 81 surveillance cultures of patients admitted to the four largest intensive care units in Hospital São Paulo in February, 2006. Presence of the vanA gene was assayed by PCR and PFGE analysis was used for molecular characterization. All VRE strains carried the vanA gene. Two distinct clonal groups were observed among vancomycin-resistant E. faecalis. Vancomycin-resistant E. faecium belonged to five distinct clones were demonstrated by molecular typing. All of these clones were different from the first vancomycin-resistant enterococci clone isolated eight years ago in our hospital.

Lack of methicillin-resistant Staphylococcus aureus nasal carriage among patients at a primary-healthcare unit in Porto Alegre, Brazil

INTRODUCTION: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a pathogen in individuals without traditional risk factors. MATERIAL AND METHODS: MRSA nasal carriage was assessed in individuals consulting at a Primary Health Unit in Brazil. RESULTS: A total of 336 individuals were included: 136 were tested only for MRSA and 200 for any S. aureus. No MRSA was found among the 336 individuals and 23 (11.5%) of 200 were colonized by S. aureus. DISCUSSION: Low prevalence rates have been found in non-hospitalized individuals, but MRSA surveillance should be encouraged to monitor clinical and molecular epidemiology of CA- MRSA.

In vitro SCREENING ANTIBACTERIAL ACTIVITY OF Bidens pilosa LINNÉ AND Annona crassiflora MART. AGAINST OXACILLIN RESISTANT Staphylococcus aureus (ORSA) FROM THE AERIAL ENVIRONMENT AT THE DENTAL CLINIC

Currently multiresistant Staphylococcus aureus is one common cause of infections with high rates of morbidity and mortality worldwide, which directs scientific endeavors in search for novel antimicrobials. In this study, nine extracts from Bidens pilosa (root, stem, flower and leaves) and Annona crassiflora (rind fruit, stem, leaves, seed and pulp) were obtained with ethanol: water (7:3, v/v) and their in vitro antibacterial activity evaluated through both the agar diffusion and broth microdilution methods against 60 Oxacillin Resistant S. aureus (ORSA) strains and against S. aureus ATCC6538. The extracts from B. pilosa and A. crassiflora inhibited the growth of the ORSA isolates in both methods. Leaves of B. pilosa presented mean of the inhibition zone diameters significantly higher than chlorexidine 0.12% against ORSA, and the extracts were more active against S. aureus ATCC (p < 0.05). Parallel, toxicity testing by using MTT method and phytochemical screening were assessed, and three extracts (B. pilosa, root and leaf, and A. crassiflora, seed) did not evidence toxicity. On the other hand, the cytotoxic concentrations (CC50 and CC90) for other extracts ranged from 2.06 to 10.77 mg/mL. The presence of variable alkaloids, flavonoids, tannins and saponins was observed, even though there was a total absence of anthraquinones. Thus, the extracts from the leaves of B. pilosa revealed good anti-ORSA activity and did not exhibit toxicity.