The linkage with apolipoprotein (a) in lipoprotein (a) modifies the immunochemical and functional properties of apolipoprotein B

Lipoprotein (a) [Lp(a)] was isolated from several donors and its apolipoprotein (a) [apo(a)] dissociated by a reductive treatment, generating the apo(a)-free form of Lp(a) [Lp(a--)] that contains apolipoprotein B (apo B) as its sole protein. Using anti-apo B monoclonal antibodies, the properties of apo B in Lp(a), Lp(a--), and autologous low-density lipoprotein (LDL) were compared. Marked differences in apo B immunoreactivity were found between these lipoproteins, due to the presence of apo(a) in Lp(a). Apo(a) enhanced the expression of two epitopes in the amino-terminal part of apo B while it diminished the immunoreactivity of three other epitopes in the LDL receptor binding domain. Accordingly, the binding of the lipoproteins to the LDL receptor was also decreased in the presence of apo(a). In a different experimental system, the incubation of antibodies that react with 27 distinct epitopes distributed along the whole length of apo B sequence with plastic-bound Lp(a) and Lp(a--) failed to reveal any epitope of apo B that is sterically hindered by the presence of apo(a). Our results demonstrate that the presence of apo(a) modified the organization and function of apo B in Lp(a) particles. The data presented indicate that most likely the modification is not due to a steric hindrance but that some more profound conformational changes are involved. We suggest that the formation of the disulfide bridge between apo B and apo(a) in Lp(a) alters the system of disulfide bonds present in apo B and thereby modifies apo B structure.     

A new species of the Neotropical loricariid Hypostomus cochliodon group (Hypostominae) from the lower Rio Tapajós basin,Brazilian Amazon

A new species of Hypostomus with spoon-shaped teeth is described from the Rio Cupari basin, a right margin affluent of the lower Rio Tapajós, Pará State, Brazil. The new species inhabits rocky bottom areas in the main channel of Rio Cupari and its tributaries. The new species can be distinguished from all its congeners, except from the Hypostomus cochliodon group, by having six to eight spoon-shaped teeth, dentaries angled at less than 80° and the absence of a notch between the hyomandibular and the metapterygoid. The new species is distinguished from all species of the H. cochliodon group by its unique colour pattern, containing dark vermiculations on head and anterior portion of the trunk, and by the absence of medial buccal papillae.     

Taxonomic revision of Hypostomus albopunctatus (Siluriformes: Loricariidae) reveals a new piece of the Hypostomus jigsaw in the upper Rio Paraná basin

Hypostomus albopunctatus was described from the Rio Piracicaba, a tributary of the Rio Tietê, upper Rio Paraná basin. Nevertheless, specimens attributed to this species are commonly found throughout other river systems in the upper Rio Paraná basin and present varying degrees of morphological variation. A taxonomic review of H. albopunctatus based on large series of specimens from many localities throughout the upper Rio Paraná basin was carried out. Results support H. lexi, H. niger and H. scaphyceps as junior synonyms. Hypostomus albopunctatus differs from all congeners except H. heraldoi by having pectoral-fin spine equal to or shorter than pelvic-fin spine (v. longer); it differs from H. heraldoi by having white or light yellow spots on the body and fins (v. dark brown or black spots). Despite conspicuous variation related to the shape and size of the spots and snout morphology, both spot and snout patterns overlapped among the examined populations, thus this variation was inferred to be intraspecific within a widely distributed H. albopunctatus.     

The Uptake of Integrated Perinatal Prevention of Mother-to-Child HIV Transmission Programs in Low- and Middle-Income Countries: A Systematic Review

Background

The objective of this review was to assess the uptake of WHO recommended integrated perinatal prevention of mother-to-child transmission (PMTCT) of HIV interventions in low- and middle-income countries.

Methods and Findings

We searched 21 databases for observational studies presenting uptake of integrated PMTCT programs in low- and middle-income countries. Forty-one studies on programs implemented between 1997 and 2006, met inclusion criteria. The proportion of women attending antenatal care who were counseled and who were tested was high; 96% (range 30–100%) and 81% (range 26–100%), respectively. However, the overall median proportion of HIV positive women provided with antiretroviral prophylaxis in antenatal care and attending labor ward was 55% (range 22–99%) and 60% (range 19–100%), respectively. The proportion of women with unknown HIV status, tested for HIV at labor ward was 70%. Overall, 79% (range 44–100%) of infants were tested for HIV and 11% (range 3–18%) of them were HIV positive. We designed two PMTCT cascades using studies with outcomes for all perinatal PMTCT interventions which showed that an estimated 22% of all HIV positive women attending antenatal care and 11% of all HIV positive women delivering at labor ward were not notified about their HIV status and did not participate in PMTCT program. Only 17% of HIV positive antenatal care attendees and their infants are known to have taken antiretroviral prophylaxis.

Conclusion

The existing evidence provides information only about the initial PMTCT programs which were based on the old WHO PMTCT guidelines. The uptake of counseling and HIV testing among pregnant women attending antenatal care was high, but their retention in PMTCT programs was low. The majority of women in the included studies did not receive ARV prophylaxis in antenatal care; nor did they attend labor ward. More studies evaluating the uptake in current PMTCT programs are urgently needed.     

Trichinella spiralis: the influence of short chain fatty acids on the proliferation of lymphocytes, the goblet cell count and apoptosis in the mouse intestine

This study was carried out to determine the influence of short chain fatty acids (SCFA) on spleen and mesenteric lymph node lymphocyte proliferation, goblet cells and apoptosis in the mouse small intestine during invasion by Trichinella spiralis. BALB/c mice were infected with 250 larvae of T. spiralis. An SCFA water solution containing acetic, propionic and butyric acids (30:15:20 mM) was administered orally starting 5 days before infection and ending 20 days post infection (dpi). Fragments of the jejunum were collected by dissection 7 and 10 dpi, and were examined for apoptotic cells in the lamina propria of the intestinal mucosa, and for goblet cells. The proliferation index of the cultured spleen and mesenteric lymph node lymphocytes with MTT test was also determined. The orally administered SCFA solution decreased the proliferation of mesenteric lymph node lymphocytes in the mice infected with T. spiralis at both examination times, but did not influence the proliferative activity of the spleen cells. Seven dpi, both in the spleen and mesenteric lymph nodes, the highest proliferation index of concanavalin A (Con A)-stimulated lymphocytes was found in the group of uninfected animals receiving SCFA animals. This tendency could still be seen 10 dpi in the mesenteric lymph nodes but not in the spleen, where the proliferation index in this group had significantly decreased. In vitro studies revealed, that butyric and propionic acids added to the cell cultures suppressed the proliferation of Con A-stimulated mesenteric lymph nodes and spleen lymphocytes taken from uninfected and T. spiralis-infected mice. Acetic acid stimulated proliferation of splenocytes taken from uninfected mice but did not affect lymphocyte proliferation in mesenteric lymph nodes from uninfected or infected mice. Orally administered SCFA increased the number of goblet cells found in the epithelium of the jejunum 7 dpi, but this number had decreased 10 dpi. The number of apoptotic cells in the lamina propria of the intestinal mucosa of animals infected with the T. spiralis and receiving SCFA was also lower, particularly 10 dpi. The above results show that SCFA can participate in the immune response during the course of trichinellosis in mice.