HIV-1 viremia during the first 28 weeks of pregnancy is not associated with mother-to-child transmission

It is currently recommended that antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV be initiated at 14 weeks of gestation. However, the relevance of early-gestation HIV viral load level for intrauterine MTCT is unknown. The objective of this study was to determine the relationship between prenatal maternal viral load and intrauterine MTCT. Records of HIV-infected pregnant women in two centers in Brazil, from 1999 to 2004 were analyzed. Three pregnancy periods were considered: earlier than 14 weeks, 14 to 27 6/7 weeks, and 28 weeks of gestation or more. Peripartum HIV exposure was also computed. Maximum viral load in each period was the measure of HIV exposure. Four hundred fifty-seven HIV-infected pregnant women were evaluated, but 53 were excluded. The MTCT rate was 0.49 percent (2/404-95 percent confidence interval (CI95) = 0.14-1.79 percent). Newborns were not breast-fed. Median viral load for the earlier-than-14-week period was 9,900 copies/mL (P25-75 1,000-50,775 copies/mL), 8,350 copies/mL (P25-75 707-42,000 copies/mL) for the 14 to 27 6/7-week period, and 435 copies/mL (P25-75 90-7,775 copies/mL) after the 28-week period. The peripartum median viral load was 400 copies/mL (P25-75 80-500 copies/mL). MTCT in mothers with VL > 1,000 copies/mL during the first 14 weeks (0.67 percent, 2/298) was not different from those with VL =1,000 copies/mL (0.0 percent, 0/96, P=1). Analogously, in the 14 to 27 6/7-week period, MTCT was similar in groups with VL higher (0.68 percent, 2/292) or lower (0 percent, 0/106) than 1,000 copies/mL (P=1). Regarding VL >1,000 copies/mL at 28-weeks-or-later and at peripartum periods, MTCT rates were 1.15 percent (2/173, P = 0.18) and 2.8 percent (2/71, P = 0.03), respectively. Intrauterine transmission does not seem to be influenced by HIV viremia during the first 28 weeks of pregnancy.

HIV-1 viremia during the first 28 weeks of pregnancy is not associated with mother-to-child transmission.

It is currently recommended that antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV be initiated at 14 weeks of gestation. However, the relevance of early-gestation HIV viral load level for intrauterine MTCT is unknown. The objective of this study was to determine the relationship between prenatal maternal viral load and intrauterine MTCT. Records of HIV-infected pregnant women in two centers in Brazil, from 1999 to 2004 were analyzed. Three pregnancy periods were considered: earlier than 14 weeks, 14 to 27 6/7 weeks, and 28 weeks of gestation or more. Peripartum HIV exposure was also computed. Maximum viral load in each period was the measure of HIV exposure. Four hundred fifty-seven HIV-infected pregnant women were evaluated, but 53 were excluded. The MTCT rate was 0.49% (2/404-95% confidence interval (CI95) = 0.14-1.79%). Newborns were not breast-fed. Median viral load for the earlier-than-14-week period was 9,900 copies/mL (P25-75 1,000-50,775 copies/mL), 8,350 copies/mL (P25-75 707-42,000 copies/mL) for the 14 to 27 6/7-week period, and 435 copies/mL (P25-75 90-7,775 copies/mL) after the 28-week period. The peripartum median viral load was 400 copies/mL (P25-75 80-500 copies/mL). MTCT in mothers with VL > 1,000 copies/mL during the first 14 weeks (0.67%, 2/298) was not different from those with VL =1,000 copies/mL (0.0%, 0/96, P=1). Analogously, in the 14 to 27 6/7-week period, MTCT was similar in groups with VL higher (0.68%, 2/292) or lower (0%, 0/106) than 1,000 copies/mL (P=1). Regarding VL >1,000 copies/mL at 28-weeks-or-later and at peripartum periods, MTCT rates were 1.15% (2/173, P = 0.18) and 2.8% (2/71, P = 0.03), respectively. Intrauterine transmission does not seem to be influenced by HIV viremia during the first 28 weeks of pregnancy.

[Reduction of vertical HIV transmission: a challenge for nursing care]. / Redução da transmissão vertical do HIV: desafio para a assistência de enfermagem.

With the crescent rates of HIV infection within female population in reproductive age, we may observe a correspondent increase in congenital infections. Thus, the obstetric nurse must be updated to participate and to develop programs of pre-natal care for HIV pregnant women. The purpose of this study was to review the pre-natal follow-up of this population regarding nursing care. Authors did not intend to approach all aspects of this subject, especially considering that investigations extend the great improvements already achieved since the acknowledge of the disease.

Intercontinental spread of a multidrug-resistant methicillin-resistant Staphylococcus aureus clone.

Two hundred ten methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered between 1990 and 1997 from three Portuguese hospitals located in Lisbon and Oporto were analyzed by molecular fingerprinting techniques. The hybridization of ClaI restriction digests with the mecA- and Tn554-specific DNA probes combined with pulsed-field gel electrophoresis documented the abrupt appearance and extensive intrahospital spread of the Brazilian epidemic MRSA clone in the 1995 samples of each one of the three hospitals analyzed-suggesting the intercontinental transfer of this strain from Brazil to Portugal. The appearance of this clone may challenge the dominance of another highly epidemic imported clone-the Iberian MRSA, currently the most widely spread MRSA clone in Portuguese hospitals.

Phase transitions in phosphatidylcholine multibilayers.

The (2)H NMR spectrum of a multilamellar dispersion of 1-myristoyl-2-[14,14,14-(2)H(3)]myristoyl-sn-glycero-3-phosphocholine with 1 mol% cholesterol in excess water has been recorded at temperatures between -15 degrees C and 36 degrees C. Motionally averaged quadrupole coupling constants nu(Q) and motionally induced asymmetry parameters eta are obtained by spectral analysis. Values of these quantities indicate that, at temperatures below -4 degrees C, any rotational motion of the molecules about their molecular long axis is slow on the NMR time scale. At temperatures immediately above the pretransition these same parameters show that a fast-rotational motion is occurring about the molecular long axis. This rotational motion is hindered in that the molecules flip about a twofold symmetry axis. Between -4 degrees C and the pretransition, spectra appear as the superposition of two powder patterns, one corresponding to the pattern observed below -4 degrees C and the other to the pattern above the pretransition. The relative contribution of the latter increases with temperature until the pretransition is reached. These data have been interpreted in two ways: either the sample between -4 degrees C and the pretransition contains two populations of rapidly and slowly rotating molecules, or there is only a single population of molecules undergoing a 180 degrees flipping motion on the time scale of the NMR measurement. The latter interpretation is more consistent with other experimental findings. At the temperature of the main transition the hydrocarbon chains melt. In the absence of cholesterol, spectra are more complex in that the line shape is reproduced by the superposition of three spectral powder patterns between -4 degrees C and the pretransition and by the superposition of two spectral patterns above the pretransition. It is postulated that these two patterns observed above the pretransition are in direct correspondence to the two ripple structures observed by freeze-fracture electron microscopy in the absence of cholesterol.

Orientational order and rotational diffusion of the head group in the bilayer membrane. A nuclear magnetic resonance study.

An order parameter-based interpretation is applied to the temperature dependence of the deuterium magnetic resonance splittings and the anisotropic contribution to the chemical shift for 31P from the head groups of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). It is shown that the rotational motion of the molecule about its long axis is not a free rotational motion as normally assumed, but instead a biased one. Changes in the degree of biasing appear to be primarily responsible for the variation of the NMR spectra with temperature. The degree of biasing is described by orientational order parameters. With the use of these order parameters, it is shown that the temperature dependence of the anisotropic contribution to the chemical shift for 31P can be predicted from that of the deuterium quadrupole splittings.