Simple feed-forward wide-range frequency offset estimator for optical coherent receivers.

We propose and experimentally demonstrate a hardware-efficient, feed-forward, wide-range frequency offset estimator for DSP-based optical coherent receivers. Using a simple relationship of signal spectrum, this estimator is capable to estimate offsets in a range compliant with OIF requirements. Obtained results show that this estimator has a high tolerance to spectrum asymmetry caused by electrical and optical signal filtering, even when using return-to-zero pulse shaping.

Microsatellite loci: determining the genetic variability of Plasmodium vivax.

OBJECTIVE: To describe the genetic diversity of Plasmodium vivax isolates from different areas in the Brazilian Amazon using 11 polymorphic microsatellites and to evaluate the correlation between microsatellite variation and repeat array length. METHODS: Microsatellites with variable repeat units and array lengths were selected using in silico search of the P. vivax genome. We designed primers and amplified the selected loci in DNA obtained from patients with P. vivax acute infections. RESULTS: Positive correlation between repeat array length and microsatellite variation was detected independently of the size of repeat unit (di, tri, or tetranucleotide). We used these markers to describe the genetic variability of P. vivax isolates from four geographic regions of the Brazilian Amazon. Substantial variability was observed among P. vivax isolates within populations, concurrent with high levels of multiple-clone infections and high linkage disequilibrium. Overall, structured populations were observed with moderate to high genetic differentiation. CONCLUSION: The markers studied are useful tools for assessing population structure of P. vivax, as demonstrated for Brazilian populations and for searching for evidence of recent selection events associated with different phenotypes, such as drug resistance.

Naturally acquired inhibitory antibodies to Plasmodium vivax Duffy binding protein are short-lived and allele-specific following a single malaria infection.

The Duffy binding protein of Plasmodium vivax (DBP) is a critical adhesion ligand that participates in merozoite invasion of human Duffy-positive erythrocytes. A small outbreak of P. vivax malaria, in a village located in a non-malarious area of Brazil, offered us an opportunity to investigate the DBP immune responses among individuals who had their first and brief exposure to malaria. Thirty-three individuals participated in the five cross-sectional surveys, 15 with confirmed P. vivax infection while residing in the outbreak area (cases) and 18 who had not experienced malaria (non-cases). In the present study, we found that only 20% (three of 15) of the individuals who experienced their first P. vivax infection developed an antibody response to DBP; a secondary boosting can be achieved with a recurrent P. vivax infection. DNA sequences from primary/recurrent P. vivax samples identified a single dbp allele among the samples from the outbreak area. To investigate inhibitory antibodies to the ligand domain of the DBP (cysteine-rich region II, DBP(II)), we performed in vitro assays with mammalian cells expressing DBP(II) sequences which were homologous or not to those from the outbreak isolate. In non-immune individuals, the results of a 12-month follow-up period provided evidence that naturally acquired inhibitory antibodies to DBP(II) are short-lived and biased towards a specific allele.

Inhibitory properties of the antibody response to Plasmodium vivax Duffy binding protein in an area with unstable malaria transmission.

The function of the Plasmodium vivax Duffy binding protein (DBP) during the erythrocyte invasion process is critical for successful parasite growth and pathogenesis in human infections. Although DBP is the subject of intensive malaria vaccine research, investigations on the functional proprieties of anti-DBP antibodies in the human population have been limited [Infect Immun68 (2000) 3164]. In the present study, we examined the ability of sera from different populations of the Brazilian Amazon--an area of markedly unstable malaria transmission--to inhibit the erythrocyte-binding function of the DBP ligand domain (region II, DBP(II)). We found that long-term exposure to malaria in the Amazon area elicits DBP-specific antibodies that inhibit the binding of different DBP(II) variants to erythrocytes. Despite the great variability of inhibitory antibody responses observed among study participants, we observed a positive correlation between erythrocyte binding-inhibitory activity and enzyme-linked immunosorbent assay anti-DBP antibodies. Of importance, there was a non-significant tendency towards increased levels of anti-DBP antibodies among individuals with asymptomatic P. vivax infections.

Bleeding reduction after topical application of tranexamic acid together with Betadine solution in total knee arthroplasty. A randomised controlled study.

INTRODUCTION: Topical application of tranexamic acid to the knee joint before closure in total knee arthroplasty reduces postoperative bleeding without increase in complication. However, it is unknown the effectiveness of topic TXA performed with other topical medications, like povidone-iodine solution. MATERIALS AND METHODS: One hundred and twenty-five patients were randomized to receive 100mL of povidone-iodine solution (control: group A) or 1.5 (group B) and 3.0 g (group C) of topical TXA in povidone-iodine solution applied into the knee before closure in total knee arthroplasty. RESULTS: The patients in the TXA groups had higher mean postoperative hemoglobin levels (P=0.01 and P=0.03 in groups B and C, respectively) and a reduced postoperative blood loss in the TXA groups (P=0.07 and P=0.09 in groups B and C, respectively). No significant complications were observed. DISCUSSION: In this study, topical application of tranexamic acid after total knee arthroplasty together with povidone-iodine solution results in higher postoperative hemoglobin levels and lower blood loss compared with those in the control group without other complications. LEVEL OF EVIDENCE: I - I: high-powered prospective randomized trial.

ELISPOT assay to measure antigen-specific murine CD8(+) T cell responses.

The enzyme-linked immunospot technique (ELISPOT) relies on the visualization of cytokine secretion by individual T cells following in vitro stimulation with antigen. This assay has been developed and standardized for the quantitative detection of antigen-specific CD8(+) T cells in mice subjected to different immunization protocols [J. Immunol. Methods 181 (1995) 45]. We have identified important variables that affect the efficacy of the ELISPOT assay and in this protocol we describe this methodology in detail. As a model, we used the production of interferon-gamma by CD8(+) T cells from peripheral blood, spleen and liver of mice immunized with malaria sporozoites expressing the H-2K(d)-restricted SYVPSAEQI. This protocol has also been used successfully to detect Th1 and Th2 epitope specific CD4(+) T cells.

Cellular responses to Plasmodium falciparum major surface antigens and their relationship to human activities associated with malaria transmission.

In Brazil, two types of activities have led to the worsening of malarial transmission in the Amazon region: prospecting/mining and agricultural settlements. In the present study, we analyze the cellular response of 52 of these individuals (14 gold-miners and 38 farmers) living within the same endemic area. Two Plasmodium falciparum major surface antigens (recombinant proteins) were used for cellular proliferative assays: circumsporozoite protein and merozoite surface protein-1. The frequency of these cellular responses were significantly higher among the miners (57-64%) than the farmers (10-20%) when either recombinant protein was used. Our data suggest that a higher exposure to malaria of the gold-miners contributed to their higher in vitro cellular response compared with the farmers. These findings point the way to further studies evaluating the influence of risk factors associated with the life styles of different social groups and the immune responses to these antigens.

A method for screening drugs against the liver stages of malaria using Plasmodium gallinaceum and Aedes mosquitos.

1. The radical cure of human malaria caused by Plasmodium vivax requires two drugs, i.e., a blood schizontocide such as chloroquine to clear the circulating parasites, and primaquine aimed at the liver stages (hyponozoites) responsible for the late relapses of this parasite. Primaquine is unique as a radical curative drug but is highly toxic. The only useful model currently available for screening drugs to replace primaquine is Plasmodium cynomolgi-induced malaria in Rhesus monkeys. Because of the limited availability and cost of these animals, the development of non-primate models for such screening would be of considerable value. 2. We used a drug-screening assay for the liver stage malaria parasite based on the ability of such drugs to stop development of gametocytes in the mosquito vector. The inhibition of the sporogonic cycle of malaria in the mosquito by primaquine (15 mg/kg) was confirmed here and used for re-evaluation of the gametocyte method. 3. We observed that the level of parasitemia in the untreated control chicken used to infect mosquitos was a crucial factor affecting the subsequent development of sporogony. Thus, parasitemia was carefully controlled in the studies involving oocyst development. Parasitemias lower than 6% at the beginning of the experiment and increasing were found to be most appropriate for the production of the infectious gametocytes during a period of 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro activity of natural and synthetic naphthoquinones against erythrocytic stages of Plasmodium falciparum.

In an attempt to identify new antimalarial compounds we studied the blood schizonticide effect of chemically defined natural products which were isolated from plants (Bignoniaceae) or synthesized. Different concentrations of these drugs (up to 20 microM) were incubated in vitro with blood forms of Plasmodium falciparum for 72 h. A total of 12 drugs of the naphthoquinones group were tested. Eight of them were isolated from plants (NP) and 4 synthesized (S). Three of the drugs (2 NP and one S) were very active and completely inhibited parasite growth at the higher concentrations used (20 microM); 5 drugs were partially active (3S and 2NP) and 3 (NP) were totally inactive. Lapachol was among the drugs tested. Although it has been considered a potential antimalarial agent, it exhibited very low activity (20% inhibition of schizogony). The antimalarial activity of our naphthoquinones against drug-resistant strains was superior to that of chloroquine and quinine which were used as controls. Two of the P. falciparum strains used for the tests were strongly chloroquine resistant. If these naphthoquinones prove to be active in vivo and are of low toxicity, they will be promising candidates for treatment of human malaria particularly since they are easily synthesized.

Antimalarial activity of crude extracts from Brazilian plants studied in vivo in Plasmodium berghei-infected mice and in vitro against Plasmodium falciparum in culture.

1. Ninety-five crude extracts obtained with either organic solvents or water from 48 Brazilian plants or parts of plants were evaluated experimentally as blood schizontocides. Seventy-three extracts were obtained from 33 plants randomly collected using an empirical approach, and 22 from 15 "medicinal" plants. 2. The crude extracts were screened in vivo at up to 1.0 g/kg, po, for 4 days in mice infected with blood forms of Plasmodium berghei and parasitemia was determined on the fifth day. 3. Six plants, 2 randomly collected, Vernonia brasiliana and Eupatorium squalidum, and 4 "medicinal" plants, Acanthospermum australe, Esenbeckia febrifuga, Lisianthus speciosus, and Tachia guianensis, were partly active against the rodent malaria, i.e., they showed 40-50% inhibition of P. berghei multiplication. Forty-two plants whose extracts presented no antimalarial activity are reported. 4. Four extracts with antimalarial activity were also tested in vitro using P. falciparum cultures and two of them, V. brasiliana and A. australe, were active. Extracts of V. brasiliana caused about 50% inhibition of parasite multiplication at relatively low doses (40 ng/ml) as compared to chloroquine (30 ng/ml) and quinine (50 ng/ml). 5. The relatively high percentage of positive results obtained here for "medicinal" plants vs randomly chosen plants demonstrates the effectiveness of the ethnopharmacological approach to drug testing.

Molecular genetic approach to cell proliferation control and neoplasia.

A number of gene products involved in the control of cell proliferation fall into one of two classes: oncogenes and tumor suppressor genes. The same gene products have also been associated with malignant growth (tumors) caused by radiation, chemicals and tumor viruses. Here we describe our attempts to elucidate the molecular mechanisms underlying polyomavirus-induced cell transformation and the anti-tumor activity of glucocorticoid hormones. Wild type and mutant polyomavirus middle T (MT) overexpressing cell lines, generated with retroviral vector constructs, were used to investigate the role played by peptide growth factor primary response genes (fos, jun, myc, JE, KC) in viral transformation and to map the transduction pathway of the mitogenic signal of MT. Overexpression of MT leads to increased AP-1 (Fos/Jun) transcriptional complex activity. Transformation defective mutant analysis allowed the identification of sites in the MT molecule that are crucial for this activity. Two different approaches were used to investigate the molecular basis for glucocorticoids anti-tumor activity, namely: blind cloning of cDNAs and analysis of growth control genes in C6 glioma cell variants that are either hypersensitive (C6/ST1) or unresponsive to glucocorticoids (C6/P7). Four different glucocorticoid-regulated cDNA sequences were isolated using differential hybridization. A number of differentially expressed sequences were isolated from glucocorticoid-treated C6/ST1 cells by differential display (DDRT-PCR) and are currently being characterized. Expression of known growth control genes in C6/ST1 cells allowed the identification of important candidates for glucocorticoid hormone targets.

[Infectious mononucleosis.]. / Mononucleose infecciosa.

OBJECTIVE: To present updated aspects of the Infectious Mononucleosis caused by the Epstein-Barr Virus. MATERIALS AND METHODS: Research of bibliographic references through the Medline and direct research of selected papers. RESULTS: A concise approach to some aspects related to the epidemiology of the virus, namely the two types that are presently known,EBVtypeAandEBVtype B, and some differences that they present. It was possible to establish a relationship between what one sees in the clinical picture and the immunological changes that occur at the same time. The author also describes the physiopathology, clinical features, complications and other syndromes associated to the EBV. As far as the laboratory workup is concerned, it is important to have a complete blood count as the first step, followed by the quantitative exam of the heterophile antibodies and antibodies antiEBV analysis. CONCLUSION: The pathologies related to the EBV are important, and certainly fascinating from the immunological point of view. Among these, the Infectious Mononucleosis caused by the EBV has shown some interesting clinical and laboratorial aspects.

Real-time multiplex allele-specific polymerase chain reaction for genotyping of the Duffy antigen, the Plasmodium vivax invasion receptor.

BACKGROUND AND OBJECTIVES: Duffy blood group is of major interest in clinical medicine as it is not only involved in blood-transfusion risks and occasionally in neonatal haemolytic disease, but it is also the receptor for the human malaria parasite Plasmodium vivax in the erythrocyte invasion. The aim of this study was to develop a rapid and inexpensive approach for high-throughput Duffy genotyping. MATERIALS AND METHODS: This paper reported the development of a Duffy genotyping assay based on multiplex real-time polymerase chain reaction (PCR) using SYBR Green I fluorescent dye. RESULTS: By using this approach for Duffy genotyping we obtained the same results as that for the conventional allele-specific PCR, however, in a high-throughput assay. The Duffy genotyping of field samples demonstrated that P. vivax-infected individuals showed a significantly higher prevalence of two functional alleles than Plasmodium falciparum-infected and non-infected individuals. This finding corroborates the hypothesis that the presence of two functional alleles increases the risk of P. vivax infection. CONCLUSION: This methodology may be suitable for epidemiological studies, particularly for exploring the relationship between Duffy alleles and malaria susceptibility, and also for identification of transfusional incompatibility in blood banks.

Effects of nandrolone decanoate compared with placebo or testosterone on HIV-associated wasting.

Objectives Current research is unclear about the most effective pharmacological agents for managing the loss of weight and fat-free mass common in HIV/AIDS. The aim of this study was to compare nandrolone decanoate with placebo and testosterone. Methods The study was a multicentre randomized double-blind placebo-controlled trial. Three hundred and three adult HIV-positive male patients with a weight loss of 5-15% in the last 12 months, or a body mass index of 17-19 kg/m(2), or a body cell mass/height ratio lower than 13.5 kg/m, were randomly assigned to receive nandrolone decanoate (150 mg), testosterone (250 mg) or placebo intramuscularly every 2 weeks for 12 weeks. Fat-free mass, weight, immune markers and perception of treatment were the main outcome measures. Results Treatment with nandrolone resulted in significantly greater increases in fat-free mass [mean increase 1.34 kg; 95% confidence interval (CI) 0.60; 2.08 kg] and in weight (mean increase 1.48 kg; 95% CI 0.82; 2.14 kg) compared with placebo. The mean increase in weight with nandrolone of 1.00 kg (95% CI 0.27; 1.74 kg) when compared with testosterone was significant, although the difference in fat free mass did not reach significance (mean increase 0.69 kg; 95% CI-0.13; 1.51 kg). Patient perception of benefit was significantly greater in the nandrolone group when compared with both the placebo and the testosterone groups. Conclusions Treatment with nandrolone decanoate increased body weight when compared with placebo and testosterone. Nandrolone decanoate treatment resulted in greater increases in fat-free mass than placebo and demonstrated a trend for a significant increase when compared with testosterone.

Scaling and root planing, systemic metronidazole and professional plaque removal in the treatment of chronic periodontitis in a Brazilian population II--microbiological results.

OBJECTIVE: The current investigation evaluated changes in levels and proportions of 39 bacterial species in subgingival plaque samples after scaling and root planing (SRP) alone or in combination with systemic metronidazole and/or professional cleaning in subjects with chronic periodontitis. METHODS: Forty-four adult subjects (mean age 45+/-6 years) with periodontitis were randomly assigned in four treatment groups, a control (C, n=10) that received SRP and placebo and three test groups treated as follows: T1 (n=12): SRP and metronidazole (M, 400 mg tid) for 10 days; T2 (n=12): SRP, weekly professional supragingival plaque removal for 3 months (PC) and placebo; and T3 (n=10): SRP, M and PC. Subgingival plaque samples were taken from seven sites per subject at baseline and 90 days post-therapy. Counts of 39 subgingival species were determined using checkerboard DNA-DNA hybridization. Significance of differences over time was determined using the Wilcoxon signed ranks test and among groups using ancova. RESULTS: The mean counts of the majority of the species were reduced post-therapy in the 4 treatment groups. Counts (x 10(5)+/-SEM) of Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola were significantly reduced in groups T2 and T3. Levels of beneficial species, such as some Actinomyces species, Veillonella parvula, Streptococcus sanguis, Streptococcus oralis and Streptococcus gordonii were minimally affected in levels when the combined therapy was applied (T3). Mean proportions of red complex species decreased from 18.4% at baseline to 3% at 90 days post-therapy in group T3 (p<0.01), from 25.8% to 2.3% in group T2 (p<0.01), from 17.7% to 5.6% in group T1 (p<0.05) and from 19.4% to 8.8% in group C (NS). Proportions of the suspected periodontal pathogens from the orange complex were also markedly reduced in groups T2 and T3. CONCLUSIONS: All treatments reduced counts and proportions of red complex species. Adjunctive therapy appeared to have a greater effect and also affected members of the orange complex.

[Infectious mononucleosis] / Mononucleose infecciosa.

OBJECTIVE: To present updated aspects of the Infectious Mononucleosis caused by the Epstein-Barr Virus. MATERIALS AND METHODS: Research of bibliographic references through the Medline and direct research of selected papers. RESULTS: A concise approach to some aspects related to the epidemiology of the virus, namely the two types that are presently known,EBVtypeAandEBVtype B, and some differences that they present. It was possible to establish a relationship between what one sees in the clinical picture and the immunological changes that occur at the same time. The author also describes the physiopathology, clinical features, complications and other syndromes associated to the EBV. As far as the laboratory workup is concerned, it is important to have a complete blood count as the first step, followed by the quantitative exam of the heterophile antibodies and antibodies antiEBV analysis. CONCLUSION: The pathologies related to the EBV are important, and certainly fascinating from the immunological point of view. Among these, the Infectious Mononucleosis caused by the EBV has shown some interesting clinical and laboratorial aspects.

Antimalarial chemotherapy with natural products and chemically defined molecules.

In the present work we have described the in vivo antimalarial activity of six different plants. Two of them (Vernonia brasiliana and Eupatorium squalidum) were tested in a randomic approach among 273 crude extracts from plants; four (Acanthospermum australe, Esenbeckia febrifuga, Lisianthus speciosus and Tachia guianensis) were selected after screening 22 crude extracts from different medicinal plants used in Brazil against fever and/or malaria. We also studied chemically defined molecules and some of them showed antimalarial activity in vitro. Some aspects of recent research with natural products aiming to produce drugs are discussed.

Cross-reactive cellular immune response to circumsporozoite proteins of Plasmodium vivax and P. falciparum in malaria-exposed individuals.

Acquired immunity against the recombinant circumsporozoite protein of P. falciparum (rPfCS) or P. vivax (rPvCS) was studied in two malarious areas of the Brazilian Amazon. Cellular responsiveness, evaluated by proliferative assays, was detected in about 45% of individuals who had recovered from recent acute malaria infections. Peripheral blood mononuclear cells of individuals whose last malaria infection was by P. vivax responded more to the rCS proteins than those who had P. falciparum. Since in P. vivax infections hypnozoites in the liver retain CS antigen, this stage may have contributed to the increased cellular response. The unexpected result was that in primoinfections by P. falciparum or P. vivax the proliferative response did not correspond to the rPfCS and rPvCS, respectively. Furthermore, among the malaria-exposed individuals, there was a positive correlation between the intensity of the responses to the two rCS proteins. Our results suggest that cross-reactive epitopes exist in the CS protein of P. falciparum and P. vivax. In the areas studied, the frequency of antibodies against rPvCS and/or rPfCS ranged from 43% to 11%. Species-specific antibodies against the CS protein were detected in the primoinfected individuals. Some individuals living in the endemic area but with no clinical history of malaria were positive by serology (8%) or by in vitro proliferation (21%). However, antibodies and cellular responses against rCS were detected only in malaria-exposed individuals, since those living outside the endemic area were all negative.

Antiplasmodial triterpene from Vernonia brasiliana.

The hexane extract from leaves of Vernonia brasiliana (L.) Druce (Compositae) was active in vitro against Plasmodium falciparum and in vivo in mice infected with Plasmodium berghei. This extract was subjected to a bioassay-guided fractionation protocol based on the in vitro model. Lupeol was identified as a compound responsible for the activity, inhibiting the P.falciparum growth by 45% when tested at 25 micrograms/ml. However, this triterpene was inactive in vivo when 15 mg/kg were administered per os during four consecutive days to mice infected with P.berghei. beta-Amyrin and germanicol, isolated from the same fraction that yielded lupeol, were inactive in the in vitro assay.