Antenatal depressed mood and child cognitive and physical growth at 18-months in South Africa: a cluster randomised controlled trial of home visiting by community health workers.

AIM: To examine the child outcomes at 18-months post-birth of a population cohort of women with antenatal depressed mood, half of whom were randomly chosen to receive perinatal home visits from community health workers during pregnancy. METHOD: Pregnant women in 24 neighbourhoods (98% participation) were randomised by neighbourhood to: (1) standard clinic care (SC; 12 neighbourhoods; n = 594) or (2) the Philani Intervention Program, a home visiting intervention plus standard care (12 neighbourhoods; n = 644). The physical and cognitive outcomes of children of mothers with antenatally depressed mood (Edinburg Perinatal Depression Scale >13) in the intervention condition were compared at 18-months post-birth to children of mothers without depressed mood in pregnancy in both conditions. RESULTS: More than a third of mothers had heightened levels of antenatal depressed mood (35%), similar across conditions. Antenatal depressed mood was significantly associated with being a mother living with HIV, using alcohol and food insecurity. At 18-months, the overall cognitive and motor scale scores on the Bayley Scales of Development were similar. However, 10.3% fewer children of mothers with antenatal depressed mood in the intervention condition had cognitive scores on the Bayley Scales that were less than 85 (i.e., s.d. = 2 lower than normal) compared with children of mothers with antenatal depressed mood in the SC condition. Intervention children of mothers with antenatal depressed mood were also significantly less likely to be undernourished (Weight-for-Age Z-scores < -2). CONCLUSION: Cognitive development and child growth among children born to mothers with antenatal depressed mood can be improved by mentor mother home visitors, probably resulting from better parenting and care received early in life.

No emergence of Echinococcus multilocularis in foxes in Flanders and Brussels anno 2007-2008.

Echinococcus multilocularis is highly endemic in red foxes in southern Belgium (region of Wallonia), especially in the higher located forested areas. The north of Belgium, including the regions of Flanders and Brussels, is more urbanized and has been colonized entirely by red foxes since the 1980s. A temperospatial analysis of compiled epidemiological data from 1996 to 2003 predicted a northwest spread of the cestode from Wallonia and the Netherlands towards Flanders and Brussels (Prev. Vet. Med. 2006, 76, 137-150). In 2007-2008, none of 187 examined foxes from the north tested positive (<2.8%, α = 0.01), compared to 1.7% in 1996-1999. This suggests that the parasite is not emerging in the examined area and the endemic region has not significantly extended northwest during the last decade. The possible reasons are discussed in the article, including the relatively low altitude, milder climate or low abundance of suitable intermediate hosts. The low prevalence in foxes and the generally low infection rate in humans imply that the risk for public health in Flanders and Brussels is limited anno 2007-2008.

A proposed vitamin A supplementation programme for South Africa--design, coverage and cost.

BACKGROUND: A national survey of the micronutrient status of preschool children in South Africa established that vitamin A deficiency is a significant public health problem, requiring urgent attention. A number of immediate and long-term interventions were recommended, including the introduction of a vitamin A supplementation programme and a food fortification programme. OBJECTIVES: The aim of the study was to assist in the development and implementation of a national vitamin A supplementation programme at primary health care facilities for mothers and children. This was achieved by determining the design, coverage and cost of a national primary health care facility vitamin A supplementation programme. METHODS: Based on an extensive review of the literature, the main components of a primary health care facility vitamin A supplementation programme were identified. The annual, recurrent costs of each of the programme components were estimated for the nine provinces in South Africa. Immunisation coverage rates were used as a proxy for estimating the coverage of the programme. RESULTS: The main components of the programme were identified as: promotion, training, purchase of vitamin A capsules, distribution of vitamin A capsules to primary health care facilities, distribution of capsules to the programme beneficiaries, and monitoring and evaluation. The programme would operate from primary health care facilities and would target all children between 6 and 24 months of age and newly delivered mothers. It was estimated that the programme would cover 74% of children and 95% of postpartum women nationally. The total annual, recurrent cost of the national programme was estimated at R16.4 million. The bulk of the costs would include personnel costs, comprising 68% of the total costs. Other costs included promotion (27%), vitamin A capsules (4%) and training (1%). The cost of the programme would vary significantly by province, but the provinces' average total cost per beneficiary would be similar. CONCLUSION: A primary health care facility vitamin A supplementation programme has been designed and accompanied by an estimated overall cost and coverage for implementation. The findings of the study showed that the programme would be financially feasible and would reach the majority of children under 24 months of age. It is recommended that further research be undertaken to extend the programme to the more 'hard to reach' population using other strategies such as mass immunisation campaigns.

Notch signaling in the development of the inner ear: lessons from Drosophila.

The sensory patches in the ear of a vertebrate can be compared with the mechanosensory bristles of a fly. This comparison has led to the discovery that lateral inhibition mediated by the Notch cell-cell signaling pathway, first characterized in Drosophila and crucial for bristle development, also has a key role in controlling the pattern of sensory hair cells and supporting cells in the ear. We review the arguments for considering the sensory patches of the vertebrate ear and bristles of the insect to be homologous structures, evolved from a common ancestral mechanosensory organ, and we examine more closely the role of Notch signaling in each system. Using viral vectors to misexpress components of the Notch pathway in the chick ear, we show that a simple lateral-inhibition model based on feedback regulation of the Notch ligand Delta is inadequate for the ear just as it is for the fly bristle. The Notch ligand Serrate1, expressed in supporting cells in the ear, is regulated by lateral induction, not lateral inhibition; commitment to become a hair cell is not simply controlled by levels of expression of the Notch ligands Delta1, Serrate1, and Serrate2 in the neighbors of the nascent hair cell; and at least one factor, Numb, capable of blocking reception of lateral inhibition is concentrated in hair cells. These findings reinforce the parallels between the vertebrate ear and the fly bristle and show how study of the insect system can help us understand the vertebrate.

Sensory organ generation in the chicken inner ear: contributions of bone morphogenetic protein 4, serrate1, and lunatic fringe.

The chicken inner ear is a remarkably complex structure consisting of eight morphologically distinct sensory organs. Unraveling how these sensory organs are specified during development is key to understanding how such a complex structure is generated. Previously, we have shown that each sensory organ in the chicken inner ear arises independently in the rudimentary otocyst based on Bone morphogenetic protein 4 (Bmp4) expression. Here, we compare the expression of Bmp4 with two other putative sensory organ markers, Lunatic Fringe (L-fng) and chicken Serrate1 (Ser1), both of which are components of the Notch signaling pathway. L-fng and Ser1 expression domains were asymmetrically distributed in the otic cup. At this early stage, expression of L-fng is similar to Delta1 (Dl1), in an anteroventral domain apparently corresponding to the neurogenic region, while Ser1 is expressed at both the anterior and posterior poles. By the otocyst stage, the expression of both L-fng and Ser1 largely coincided in the medial region. All presumptive sensory organs, as identified by Bmp4 expression, arose within the broad L-fng- and Ser1-positive domain, indicating the existence of a sensory-competent region in the rudimentary otocyst. In addition, there is a qualitative difference in the levels of expression between L-fng and Ser1 such that L-fng expression was stronger in the ventral anterior, whereas Ser1 was stronger in the dorsal posterior region of this broad domain. This early difference in expression may presage the differences among sensory organs as they arise from this sensory competent zone.

Stimulation of human epidermal differentiation by delta-notch signalling at the boundaries of stem-cell clusters.

BACKGROUND: Human epidermis is renewed throughout life from stem cells in the basal layer of the epidermis. Signals from the surrounding keratinocytes influence the differentiation of the stem cells, but the nature of the signals is unknown. In many developing tissues, signalling mediated by the transmembrane protein Delta1 and its receptor Notch1 inhibits differentiation. Here, we investigated the role of Delta-Notch signalling in postnatal human epidermis. RESULTS: Notch1 expression was found in all living epidermal layers, but Delta1 expression was confined to the basal layer of the epidermis, with highest expression in those regions where stem cells reside. By overexpressing Delta1 or Delta(T), a truncated form of Delta1, in primary human keratinocytes and reconstituting epidermal sheets containing mixtures of Delta-overexpressing cells and wild-type cells, we found that cells expressing high levels of Delta1 or Delta(T) failed to respond to Delta signals from their neighbours. In contrast, wild-type keratinocytes that were in contact with neighbouring cells expressing Delta1 were stimulated to leave the stem-cell compartment and initiate terminal differentiation after a few rounds of division. Delta1 promoted keratinocyte cohesiveness, whereas Delta(T) did not. CONCLUSIONS: We propose that high Delta1 expression by epidermal stem cells has three effects: a protective effect on stem cells by blocking Notch signalling; enhanced cohesiveness of stem-cell clusters, which may discourage intermingling with neighbouring cells; and signalling to cells at the edges of the clusters to differentiate. Notch signalling in epidermal stem cells thus differs from other progenitor cell populations in promoting, rather than suppressing, differentiation.

Serrate1-induced notch signalling regulates the decision between immunity and tolerance made by peripheral CD4(+) T cells.

Signals derived from antigen-presenting cells (APC) influence the functional differentiation of CD4(+) T cells. We report here that Serrate1 (Jagged1), a ligand for the Notch1 receptor, may contribute to the differentiation of peripheral CD4(+) T cells into either helper or regulatory cells. Our findings demonstrate that antigen presented by murine APC overexpressing human Serrate1 induces naive peripheral CD4(+) T cells to become regulatory cells. These cells can inhibit primary and secondary immune responses, and transfer antigen-specific tolerance to recipient mice. Our results show that Notch signalling may help explain 'linked' suppression in peripheral tolerance, whereby tolerance induced to one epitope encompasses all epitopes on that antigen during the course of an immune response.

Cell fate choices and the expression of Notch, Delta and Serrate homologues in the chick inner ear: parallels with Drosophila sense-organ development.

The sensory patches in the vertebrate inner ear are similar in function to the mechanosensory bristles of a fly, and consist of a similar set of cell types. If they are truly homologous structures, they should also develop by similar mechanisms. We examine the genesis of the neurons, hair cells and supporting cells that form the sensory patches in the inner ear of the chick. These all arise from the otic epithelium, and are produced normally even in otic epithelium cultured in isolation, confirming that their production is governed by mechanisms intrinsic to the epithelium. First, the neuronal sublineage becomes separate from the epithelial: between E2 and E3.5, neuroblasts delaminate from the otocyst. The neuroblasts then give rise to a mixture of neurons and neuroblasts, while the sensory epithelial cells diversify to form a mixture of hair cells and supporting cells. The epithelial patches where this occurs are marked from an early stage by uniform and maintained expression of the Notch ligand Serrate1. The Notch ligand Delta1 is also expressed, but transiently and in scattered cells: it is seen both early, during neuroblast segregation, where it appears to be in the nascent neuroblasts, and again later, in the ganglion and in differentiating sensory patches, where it appears to be in the nascent hair cells, disappearing as they mature. Delta-Notch-mediated lateral inhibition may thus act at each developmental branchpoint to drive neighbouring cells along different developmental pathways. Our findings indicate that the sensory patches of the vertebrate inner ear and the sensory bristles of a fly are generated by minor variations of the same basic developmental program, in which cell diversification driven by Delta-Notch and/or Serrate-Notch signalling plays a central part.

The Notch ligand, Jagged-1, influences the development of primitive hematopoietic precursor cells.

We examined the expression of two members of the Notch family, Notch-1 and Notch-2, and one Notch ligand, Jagged-1, in hematopoietic cells. Both Notch-1 and Notch-2 were detected in murine marrow precursors (Lin-Sca-1+c-kit+). The Notch ligand, Jagged-1, was not detected in whole marrow or in precursors. However, Jagged-1 was seen in cultured primary murine fetal liver stroma, cultured primary murine bone marrow stroma, and in stromal cell lines. These results indicate a potential role for Notch-Notch ligand interactions in hematopoiesis. To further test this possibility, the effect of Jagged-1 on murine marrow precursor cells was assessed by coculturing sorted precursor cells (Lin-Sca-1+c-kit+) with a 3T3 cell layer that expressed human Jagged-1 or by incubating sorted precursors with beads coated with the purified extracellular domain of human Jagged-1 (Jagged-1(ext)). We found that Jagged-1, presented both on the cell surface and on beads, promoted a twofold to threefold increase in the formation of primitive precursor cell populations. These results suggest a potential use for Notch ligands in expanding precursor cell populations in vitro.

Maintenance of neuroepithelial progenitor cells by Delta-Notch signalling in the embryonic chick retina.

BACKGROUND: Neurons of the vertebrate central nervous system (CNS) are generated sequentially over a prolonged period from dividing neuroepithelial progenitor cells. Some cells in the progenitor cell population continue to proliferate while others stop dividing and differentiate as neurons. The mechanism that maintains the balance between these two behaviours is not known, although previous work has implicated Delta-Notch signalling in the process. RESULTS: In normal development, the proliferative layer of the neuroepithelium includes both nascent neurons that transiently express Delta-1 (Dl1), and progenitor cells that do not. Using retrovirus-mediated gene misexpression in the embryonic chick retina, we show that where progenitor cells are exposed to Dl1 signalling, they are prevented from embarking on neuronal differentiation. A converse effect is seen in cells expressing a dominant-negative form of Dl1, Dl1(dn), which we show renders expressing cells deaf to inhibitory signals from their neighbours. In a multicellular patch of neuroepithelium expressing Dl1(dn), essentially all progenitors stop dividing and differentiate prematurely as neurons, which can be of diverse types. Thus, Delta-Notch signalling controls a cell's choice between remaining as a progenitor and differentiating as a neuron. CONCLUSIONS: Nascent retinal neurons, by expressing Dl1, deliver lateral inhibition to neighbouring progenitors; this signal is essential to prevent progenitors from entering the neuronal differentiation pathway. Lateral inhibition serves the key function of maintaining a balanced mixture of dividing progenitors and differentiating progeny. We propose that the same mechanism operates throughout the vertebrate CNS, enabling large numbers of neurons to be produced sequentially and adopt different characters in response to a variety of signals. A similar mechanism of lateral inhibition, mediated by Delta and Notch proteins, may regulate stem-cell function in other tissues.

Combined use of pleural adenosine deaminase with lymphocyte/neutrophil ratio. Increased specificity for the diagnosis of tuberculous pleuritis.

UNLABELLED: Increased pleural fluid adenosine deaminase (ADA) activity is classically associated with tuberculous pleuritis. However, increased activity can also occur in a number of other diseases and this may negatively affect the diagnostic utility of ADA measurements and decrease its specificity for the diagnosis of tuberculosis (TB). The presence of ADA in pleural fluids reflects the cellular immune response in the pleural cavity and in particularly, the activation of T lymphocytes. Different disease entities are typically associated with the presence of particular types of leukocytes. OBJECTIVE: To determine whether the combined use of ADA activity and differential cell counts would provide a more efficient means for diagnosing tuberculous pleurisy than the use of ADA levels alone. METHODS: Biochemistry, cytology, and microbiology studies were performed on 472 consecutive pleural fluids. ADA and differential cell counts were determined on all exudative effusions. RESULTS: ADA activity in tuberculous effusions was significantly higher than in any other diagnostic group (p < 0.005). At a level of 50 U/L, the sensitivity, specificity, positive predictive value (ppv), negative predictive value (npv), and efficiency for the identification of TB were calculated at 91%, 81%, 84%, 89%, and 86%, respectively. When the additional requirement of a lymphocyte neutrophil ratio of 0.75 or greater was included, the sensitivity, specificity, ppv, npv, and efficiency for the identification of TB were calculated at 88%, 95%, 95%, 88%, and 92%, respectively. CONCLUSION: ADA, especially when combined with differential cell counts and lymphocyte/neutrophil ratios, remains a useful test in the diagnosis tuberculous pleuritis.

Promoter-specific regulation of gene expression by an exogenously added homedomain that promotes neurite growth.

pAntp, a 60 amino acid long peptide corresponding to the homeodomain of the Drosophila Antennapedia protein, translocates through neuronal membranes when added exogenously to neurons in culture, where it accumulates in the nucleus and promotes neurite outgrowth. We proposed that the peptide, once internalized, may compete for homeoprotein DNA binding sites. To investigate this point, we have produced a permanent fibroblast cell line which carries a luciferase reporter gene under the control of a 93 bp genomic region of the HOXD9 promoter with binding sites for homeoproteins. Externally added pAntp specifically down-regulates the expression of the reporter gene, suggesting that the neurotrophic effects observed previously are mediated by direct binding of pAntp to homeoprotein target sites.

Use of adenosine deaminase as a diagnostic tool for tuberculous pleurisy.

BACKGROUND: A statistical audit of adenosine deaminase (ADA) in pleural effusions was undertaken. METHODS: ADA analysis, cytological and microbiological examinations, and differential cell counts were performed on 462 pleural fluid samples. RESULTS: ADA activity in tuberculous effusions was higher than in any other diagnostic group. At a level of 50 U/l the sensitivity and specificity for the identification of tuberculosis was 90% and 89%, respectively. CONCLUSIONS: ADA activity remains a useful test in the evaluation of pleural effusions.

Neurotrophic activity of a homeobox peptide.

Homeoproteins are well known for their role in defining the shape of organs during early development. The late expression of some homeogenes in the nervous system suggests that they might have other, additional functions, possibly in neurite growth and target recognition. The 60 amino acid-long peptide corresponding to the homeobox of Antennapedia (pAntp) translocates through the membrane of neurons in culture and reaches their nuclei. This process is followed by an enhanced morphological differentiation of the neurons. Internalization by neurons is four-fold that observed with fibroplasts. This difference is abolished upon treatment with Endo-N which specifically cleaves alpha,2-8 bonds in polysialic acid. To understand the mode of action of the peptide, we constructed three mutants modified in their capacity to specifically bind promoters and/or to translocate through the cell membrane. The biological properties of the mutants demonstrate that the neurotrophic action of pAntp requires its internalization and integrity of its specific DNA-binding capacity.

Neurotrophic activity of the Antennapedia homeodomain depends on its specific DNA-binding properties.

In previous reports we have demonstrated that the 60-aa peptide corresponding to the homeodomain of the Drosophila protein Antennapedia (pAntp) translocates through the membrane of neurons in culture, accumulates in neuronal nuclei, and promotes neurite growth. To analyze the importance of specific pAntp DNA-binding properties in this phenomenon we have constructed three mutant versions of pAntp that differ in their ability to translocate through the membrane and to bind specifically the cognate sequence for homeodomains present in the promoter of HoxA5. We demonstrate that removing two hydrophobic residues of the third helix inhibits pAntp internalization and suppresses its neurotrophic activity. We also show that pAntp neurotrophic activity is lost when mutations are introduced in positions preserving its penetration and nuclear accumulation but abolishing its capacity to bind specifically the cognate DNA-binding motif for homeoproteins. Our results strongly suggest that pAntp neurotrophicity requires both its internalization and its specific binding to homeobox cognate sequences. We propose that homeoproteins might regulate important events in the morphological differentiation of the postmitotic neuron.

[Neurotrophic activity of homeopeptide]. / Activité neurotrophique d'un homéopeptide.

The sixty aminoacid-long peptide corresponding to the homeobox of Antennapedia (pAntp) translocates through the membrane of neurons in culture and reaches their nuclei. This process is followed by an enhanced morphological differentiation of the neurons. Internalization by neurons is 4-fold that observed with fibroblasts. This difference is abolished upon treatment Endo-N which specifically cleaves alpha, 2-8 bounds in polysialic acid (PSA). To understand the mode of action of the peptide, we constructed three mutants modified in their capacity to specifically bind promoters and/or to translocate through the cell membrane. The biological properties of the mutants demonstrate that the neurotrophic action of pAntp requires its internalization and the integrity of its specific DNA-binding capacity.

Antennapedia homeobox peptide enhances growth and branching of embryonic chicken motoneurons in vitro.

Spinal motoneuron development is regulated by a variety of intrinsic and extrinsic factors. Among these, a possible role for homeoproteins is suggested by their expression in the motoneuron at relatively late stages. To investigate their possible involvement in motoneuron growth, we adapted a novel technique recently developed in this laboratory, based on the ability of the 60 amino acid-long homeobox of Antennapedia (pAntp) to translocate through the neuronal membrane and to accumulate in the nucleus (Joliot, A. H., C. Pernelle, H. Deagostini-Bazin, and A. Prochiantz. 1991. Proc. Natl. Acad. Sci. USA. 88:1864-1868; Joliot, A. H., A. Triller, M. Volovitch, C. Pernelle, and A. Prochiantz. 1991. New Biol. 3:1121-1134). Motoneurons from E5 chicken spinal cord were incubated with pAntp, purified by panning on SC1 antibody and plated on polyornithine/laminin substrata without further addition of pAntp. After 24 h, neurite outgrowth was already extensive in controls. In cultures of motoneurons that had been preincubated with 10(-7) M pAntp, neurite length was doubled; a similar effect was obtained using postnatal muscle extracts. Morphological analysis using a neurofilament marker specific for axons indicated that the homeobox peptide enhances primarily axonal elongation and branching. To test the hypothesis that the biological activity of pAntp involves its specific attachment to cognate homeobox binding sites present in the genome, we generated a mutant of pAntp called pAntp40P2, that was still able to translocate through the motoneuron membrane and to reach the nucleus, but had lost the specific DNA-binding properties of the wild-type peptide. Preincubation of pAntp40P2 with purified motoneurons failed to increase neurite outgrowth. This finding raises the possibility that motoneuron growth is controlled by homeobox proteins.

Neurotrophic activity of an homeobox peptide.

The sixty aminoacid-long peptide corresponding to the homeobox of Antennapedia (pAntp) translocates through the membrane of neurons in culture and reaches their nuclei. This process is followed by an enhanced morphological differentiation of the neurons. Internalization by neurons is 4-fold that observed with fibroblasts. This difference is abolished upon treatment with Endo-N which specifically cleaves alpha, 2-8 bounds in polysialic acid (PSA). To understand the mode of action of the peptide, the authors constructed three mutants modified in their capacity to specifically bind promoters and/or to translocate through the cell membrane. The biological properties of the mutants demonstrate that the neurotrophic action of pAntp requires its internalization and the integrity of its specific DNA-binding capacity.

Control of neuronal morphogenesis by homeoproteins: consequences for the making of neuronal networks.

To test whether homeoproteins can act as genetic regulators in the processes of neurite growth, branching, guidance, and connectivity, the 60 amino acid homeodomain of Antennapedia was introduced in embryonic neurons in primary culture. It was hoped that this homeopeptide would bind to specific promoters and thus behave as a competitive inhibitor of endogenous homeoproteins. The introduction of the homeodomain in the nerve cells was made easy by its unexpected capability to translocate through the membranes and to accumulate within the nuclei. The presence of the homeodomain within the cells correlated with an increase in neurite growth and branching. The absence of activity of mutant peptides, still internalized but unable to bind with high affinity to homeoprotein cognate binding sites, strongly suggested that endogenous homeoproteins modulate neurite outgrowth and branching. Moreover, the efficient internalization of the homeobox peptide by live cells in culture raises the possibility that, in addition to their well-established role as cell-autonomous transcription factors, some homeoproteins may also exert paracrine functions. We examine how these hypotheses could modify our current views on the establishment and plasticity of neuronal networks.