ABSTRACT
BACKGROUND AND OBJECTIVES: The purpose of this article was to describe the experience of screening for human immunodeficiency virus (HIV) p24 antigen (p24Ag) in blood donors, in four Brazilian Blood Banks, and to report the detection of the first window-period donation. MATERIALS AND METHODS: During 61 months (May 96 to June 01), 103 470 consecutive donations were screened for HIV p24Ag using commercially available enzyme-linked immunosorbent assay (ELISA) kits. Testing was carried out in accordance with the instructions supplied with the kits. RESULTS: Fifty-eight repeatedly reactive samples were identified [0.056% of the total; 95% confidence interval (95% CI): 0.042-0.070]. Ten of the 58 were confirmed as p24Ag positive after neutralization (0.010%; 95% CI: 0.004-0.016), nine of the 10 (0.009%; 95% CI: 0.003-0.014) were also HIV antibody positive and only one (0.001%; 95% CI: 0-0.003) was HIV antibody negative. CONCLUSIONS: In this setting the rate of sole p24Ag-positive donations was one in 103 740. This figure corresponds closely with the previously estimated yield of one in 87 796 donations. The yield of HIV p24Ag+ : Ab- has been previously estimated in our centres to be 1 : 87 796 donations, a value similar to that observed in actual practice.
Subject(s)
Blood Donors , HIV Core Protein p24/blood , Mass Screening/methods , Blood Banks , Brazil , Enzyme-Linked Immunosorbent Assay , HIV Infections/diagnosis , Humans , Predictive Value of Tests , RNA, Viral/blood , Truth DisclosureABSTRACT
The ground state of the proton-rich, unbound nucleus 11N was observed, together with six excited states using the multinucleon transfer reaction 10B(14N,13B)11N at 30A MeV incident energy at Grand Accelerateur National d'Ions Lourds. Levels of 11N are observed as well defined resonances in the spectrum of the 13B ejectiles. They are localized at 1.63(5), 2.16(5), 3.06(8), 3.61(5), 4.33(5), 5.98(10), and 6.54(10) MeV above the 10C+p threshold. The ground-state resonance has a mass excess of 24.618(50) MeV; the experimental width is smaller than theoretical predictions.
ABSTRACT
The efficacy of azithromycin and pyrimethamine in experimental infection of mice with Toxoplasma gondii was tested. Daily dosages of 200 mg/kg and 12.5 mg/kg, respectively, were given orally over a period of ten days. The medications were administered in combination or separately. The combined use of the drugs yielded better results, and a similar investigation using a cystogenic strain of the parasite will be conducted in a future study.
Subject(s)
Anti-Bacterial Agents/therapeutic use , Antiprotozoal Agents/therapeutic use , Azithromycin/therapeutic use , Pyrimethamine/therapeutic use , Toxoplasmosis, Animal/drug therapy , Animals , Ascitic Fluid/parasitology , Drug Evaluation, Preclinical , Drug Therapy, Combination , Mice , Mice, Inbred BALB C , Toxoplasma/isolation & purification , Toxoplasmosis, Animal/parasitologyABSTRACT
Resistance to chemotherapy in cancer cells is mainly mediated by overexpression of P-glycoprotein (Pgp), a plasma membrane ATP-binding cassette (ABC) transporter which extrudes cytotoxic drugs at the expense of ATP hydrolysis. Pgp consists of two homologous halves each containing a transmembrane domain and a cytosolic nucleotide-binding domain (NBD) which contains two consensus Walker motifs, A and B, involved in ATP binding and hydrolysis. The protein also contains an S signature characteristic of ABC transporters. The molecular mechanism of Pgp-mediated drug transport is not known. Since the transporter has an extraordinarily broad substrate specificity, its cellular function has been described as a "hydrophobic vacuum cleaner". The limited knowledge about the mechanism of Pgp, partly due to the lack of a high-resolution structure, is well reflected in the failure to efficiently inhibit its activity in cancer cells and thus to reverse multidrug resistance (MDR). In contrast to the difficulties encountered when studying the full-length Pgp, the recombinant NBDs can be obtained in large amounts as soluble proteins. The biochemical and biophysical characterization of recombinant NBDs is shown here to provide a suitable alternative route to establish structure-function relationships. NBDs were shown to bind ATP and analogues as well as potent modulators of MDR, such as hydrophobic steroids, at a region close to the ATP site. Interestingly, flavonoids also bind to NBDs with high affinity. Their binding site partly overlaps both the ATP-binding site and the steroid-interacting region. Therefore flavonoids constitute a new promising class of bifunctional modulators of Pgp.
Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Adenosine Triphosphate/metabolism , Antineoplastic Agents/therapeutic use , Drug Resistance, Multiple , Neoplasms/drug therapy , ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry , Adenosine Triphosphatases/metabolism , Carrier Proteins/metabolism , Drug Resistance, Neoplasm , Flavonoids/metabolism , Humans , Structure-Activity RelationshipABSTRACT
We report a human immunodeficiency virus (HIV)-infected man with chronic Chagas' disease who developed a congestive heart failure that could not be clinically controlled. Endomyocardial biopsy revealed severe myocarditis and the xenodiagnosis result was positive, but Trypanosoma cruzi by direct microscopic examination of the blood was found only four months after the symptoms had started. Treatment with benznidazole was effective in reducing parasitemia, stabilizing the clinical status, and controlling tissue damage related to the parasite. Although the finding of T. cruzi trypomastigotes by direct microscopic examination of the blood has been considered the mark of Chagas' reactivation in immunocompromised patients with chronic disease, in this case it was a late finding.
Subject(s)
AIDS-Related Opportunistic Infections/complications , Chagas Disease/complications , Heart Diseases/complications , Adult , Animals , Chagas Disease/parasitology , Chronic Disease , Heart Diseases/parasitology , Heart Diseases/pathology , Heart Failure/complications , Humans , Immunocompromised Host , Male , Myocarditis/complications , Myocarditis/parasitology , Myocarditis/pathology , Recurrence , Trypanosoma cruzi/isolation & purificationABSTRACT
The diagnosis of intestinal infection by Cryptosporidium sp is crucial today; with the progression of the AIDS epidemic, many cases of cryptosporidiosis have appeared in this setting and in other immunodeficiency diseases. We compared the advantages and disadvantages of Heine's method and modified Kinyoun's method in the following parameters: morphology of the parasite, quantitation of cysts, stability of the staining characteristics timewise on the slides and time spend at staining. All positive fecal smears were obtained from patients with AIDS. The sensitivity of these two techniques was the same. The choice should be made by the best aspects of each method. Heine's was better for quantitation of the cysts and was faster. Kinyoun's was better for conserving the stained smear.
Subject(s)
AIDS-Related Opportunistic Infections/parasitology , Cryptosporidiosis/parasitology , Cryptosporidium/isolation & purification , Feces/parasitology , Animals , Humans , Parasitology/methodsABSTRACT
Maintenance of Trypanosoma cruzi infection in Triatoma infestans was evaluated. Seventy nine fourth instar nymphs were followed by 12 months, after being fed in infected mice. The bugs were examined every month, fecal smears were done to document T. cruzi infection then the bugs were fed in "clean" (uninfected) mice. Thirty nine per cent of the bugs remained infected until death twenty three per cent cleared infection and remained uninfected until death and nineteen per cent alternated positive and negative results. Our experience agrees with the published papers in medical literature. Longevity of T. cruzi in the host depends mostly in the feeding of the bug; well fed bugs maintain infection, and long fasting correlates with infection clearance.
Subject(s)
Longevity , Triatoma/parasitology , Trypanosoma cruzi/physiology , Animals , Feeding Behavior , Host-Parasite Interactions , Mice , Mice, Inbred BALB C , Nymph , Time FactorsABSTRACT
One untested but widely held opinion in Brazil is that oral use of vitamin B complex is useful as a mosquito repellent. We exposed Balb-C mice to a large number of Culex quinquefasciatus females, after giving vitamin B complex to mice (drops by mouth). There was no difference between mice attractiveness to mosquitoes in the vitamin B group compared to normal, but very few of the females bite mice in both groups, so the experiment was inconclusive. We suggest further experiments in this subject, using other models were the animals are more attractive to mosquitoes.