Required duration of combined annual ivermectin treatment and vector control in the Onchocerciasis Control Programme in west Africa.

In the extension areas of the Onchocerciasis Control Programme in West Africa, aerial larviciding is supplemented with annual ivermectin treatment, mainly to achieve better control of morbidity. The purpose of this study is to determine whether and to what extent the addition of annual ivermectin treatment permits earlier cessation of vector control than originally recommended. The effectiveness of combined ivermectin distribution and vector control was assessed using an epidemiological model. Model predictions suggest that, dependent on the pre-control endemicity of the area and the proportion of persons treated during each ivermectin round, large-scale annual treatment permits a considerable reduction in the duration of vector control. Taking into account uncertainty about the efficacy of ivermectin, our results indicate that, provided treatment coverage is at least 65% and there is no importation of infection from elsewhere, 12 years of combined control will be sufficient to reduce the risk of recrudescence to below 1% in even the most afflicted areas.     

Redeployment of trigeminal motor axons during metamorphosis.

As a consequence of the degeneration and replacement of the jaw muscle fibers in the leopard frog, Rana pipiens, trigeminal motoneurons innervate different targets before and after metamorphosis. This investigation examined the morphological correlates of the reassignment of trigeminal motoneurons during the initial phases of myofiber turnover. Specifically, silver-cholinesterase histochemistry and electron microscopy were used to 1) identify the fate of motor axons within the neuromuscular junctions (NMJs) applied to degenerating larval myofibers and 2) to determine the origin(s) of the motor axons that innervate the postmetamorphic muscle fibers of the jaw. The results demonstrate that the NMJs are retained on larval myofibers throughout their degeneration and are readily identifiable on the residual larval basal laminae that remain after involution of the sarcoplasm. Light and electron microscopic observations provide evidence that both pre- and post-synaptic elements are present on the degenerating fibers. Furthermore, morphometric analyses indicate that the preponderance (86%) of motor axons supplying adult muscle fibers originates from the larval NMJs. This condition suggests that metamorphic redeployment of trigeminal motoneurons occurs through the resumption of growth at the axon terminal supplying larval muscle rather than through the proximal collateralization of these axons and resorption of larval terminals.     

Rapid differentiation of the major causative agents of bacterial meningitis by use of frequency-pulsed electron capture gas-liquid chromatograph: analysis of acids.

The major causative agents of bacterial meningitis, Haemophilus influenzae serogroup B, Neisseria meningitidis serogroups B and C, Klebsiella pneumoniae, Streptococcus pneumoniae, and two types of Escherichia coli, were cultured in a modified chemically defined Catlin medium and in a commercial version of the unmodified Catlin medium. The spent media were extracted under acidic conditions, and electron-capturing derivatives were prepared by derivatization with trichloroethanol or haptafluorobutyric anhydride. The derivatives were analyzed on a gas chromatograph equipped with a frequency-pulsed electron capture detector and a PEP-2 computer. The data obtained from the study show that these organisms can be easily distinguished from each other on the basis of metabolic products detected in either type of medium. Three different metabolic groups were detected within two serogroups of N. meningitidis. The methods are practical, and the new technique should offer clinical laboratories and hospitals a better method for rapid identification of this important group of pathogens.     

Genomic structure of PIR-B, the inhibitory member of the paired immunoglobulin-like receptor genes in mice

Abstract: The genes encoding the murine paired immunoglobulin-like receptors PIR-A and PIR-B are members of a novel gene family which encode cell-surface receptors bearing immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and their non-inhibitory/activatory counterparts. PIR-A and PIR-B have highly homologous extracellular domains but distinct trans-membrane and cytoplasmic regions. A charged arginine in the transmembrane region of PIR-A suggests its potential association with other transmembrane proteins to form a signal transducing unit. PIR-B, in contrast, has an uncharged transmembrane region and several ITIMs in its cytoplasmic tail. These characteristics suggest that PIR-A and PIR-B which are coordinately expressed by B cells and myeloid cells, serve counter-regulatory roles in humoral and inflammatory responses. In the present study we have determined the genomic structure of the single copy PIR-B gene. The gene consists of 15 exons and spans approximately 8 kilobases. The first exon contains the 5' untranslated region, the ATG translation start site, and approximately half of the leader peptide sequence. The remainder of the leader peptide sequence is encoded by exon 2. Exons 3–8 encode the six extracellular immunoglobulin-like domains and exons 9 and 10 code for the extracellular membrane proximal and transmembrane regions. The final five exons (exons 11–15) encode for the ITIM-bearing cytoplasmic tail and the 3' untranslated region. The intron/exon boundaries of PIR-B obey the GT-AG rule and are in phase I, with the notable exception of the three boundaries determined for ITIM-containing exons. A microsatellite composed of the trinucleotide repeat AAG in the intron between exons 9 and 10 provides a useful marker for studying population genetics.     

Rapid differentiation of the major causative agents of bacterial meningitis by use of frequency-pulsed electron capture gas-liquid chromatography: analysis of amines.

The major causative agents of bacterial meningitis (Haemophilus influenzae serogroup B, Neisseria meningitidis serogroups B and C, Klebsiella pneumoniae, Steptococcus pneumoniae, and two types of Escherichia coli) were cultured in a chemically defined medium, and selected strains were further studied in Todd-Hewitt medium. After acidic extraction of the spent media with chloroform, a basic extraction was made with chloroform to obtain amines. A third extraction was performed on re-acidified Todd-Hewitt medium with ethyl ether to obtain hydroxyacids. The extracts were derivatized with heptafluorobutyric anhydride-ethanol to form electron-capturing derivatives, and the derivatives were analyzed on a frequency-pulsed electron capture gas-liquid chromatograph (FPEC-GLC) equipped with a PEP-2 computer. The data obtained from the study showed that amines were produced by these organisms that formed characteristic patterns. Different serotypes of K. pneumoniae and the two serogroups of N. meningitidis produced different types of FPEC-GLC profiles within serotypes. E. coli produced several hydroxy acids on Todd-Hewitt medium that made it unique among the organisms studied. The methods used are practical and the techniques have potential for use in clinical laboratories and hospitals as a valuable aid for the rapid identification of the major causative agents of bacterial meningitis.     

Improved optical detection of colony enlargement and drug cytotoxicity in primary soft agar cultures of human solid tumour cells

The presence of cellular aggregates in cell suspensions derived from human solid tumours often complicates subsequent evaluation of colony formation in primary soft agar cultures (Agrez et al., 1982b). In the present study, performance of a conventional colony formation assay was observed to lack sufficient sensitivity to identify growth and active chemotherapeutic agents in the majority of specimen cultures. Modification of conventional methodologies to include filtration of cell suspensions, use of "proliferation control" and "cytotoxicity control" cultures as well as vital staining were found to be essential for the valid assessment of primary soft agar cultures in our laboratory. In addition, application of drugs to culture surface in place of culture incorporation appeared to facilitate culture performance and drug sensitivity testing.     

Understanding the Link Between Adolescent Same-Gender Contact and Unintended Pregnancy: The Role of Early Adversity and Sexual Risk Behavior

Past research suggests an apparent paradox: Women who engage in same-gender sexual behavior show higher rates of unintended pregnancy than women with exclusive other-gender sexual behavior. Such women also have disproportionate rates of early adversity (both harshness, such as abuse or neglect, and unpredictability, such as father absence). We used the Add Health data (N?=?5,617 cisgender women) to examine the relative contributions of early adversity, adolescent same-gender sexual behavior, and general sexual risk behavior to women’s risks for adult unintended pregnancy. Women who engaged in adolescent same-gender sexual behavior were more likely to report childhood adversity, and both childhood adversity and adolescent same-gender behavior made independent contributions to subsequent rates of unintended pregnancy. The association between adolescent same-gender sexual behavior and adult unintended pregnancy was partially attributable to the fact that women with adolescent same-gender sexual behavior engaged in greater sexual risk behavior more broadly. These findings suggest that same-gender sexual behavior in adolescence may relate to a broader set of sexual risk behaviors that augment future risk for unintended pregnancy, independent of sexual identity. We draw on life history theory to explain this pattern of results and suggest directions for future research.

     

In vitro combination treatment with perifosine and UCN-01 demonstrates synergism against prostate (PC-3) and lung (A549) epithelial adenocarcinoma cell lines.

PURPOSE: Antineoplastic agents often achieve antitumor activity at the expense of close to unacceptable toxicity. One potential avenue to improve therapeutic index might combine agents targeting distinct components of the same growth regulatory pathway. This might lead to more complete modulation of the target pathway at concentrations lower than those associated with limiting adventitious toxicities from either agent alone. The protein kinase antagonist UCN-01 is currently used in Phase I/II trials and has recently been demonstrated to inhibit potently PDK1. We have recently documented that the alkylphospholipid perifosine potently also inhibits Akt kinase (PKB) activation by interfering with membrane localization of Akt. This leads to the hypothesis that these two agents might act synergistically through distinct mechanisms in the PI3K/Akt proliferation and survival-related signaling pathway. EXPERIMENTAL DESIGN: The synergistic effects of UCN-01 and perifosine, on two cell lines (A-549 and PC-3), were examined using various long-term in vitro assays for cell growth, cell cycle distribution, clonogenicity, survival morphology, and apoptosis. Along with Western blotting experiments were performed to determine whether this synergistic combination of two drugs has significant effect on their downstream targets and on biochemical markers of apoptosis. RESULTS: After 72 h, perifosine at concentrations of 1.5 and 10 microM UCN-01 at 40 and 250 nM did not significantly affect the growth of PC-3 and A459 cells, respectively. However, in combination at the same respective individual concentrations (1.5 microM and 40 nM of perifosine and UCN-01, respectively, in PC-3 cells and 10 microM perifosine and 0.25 microM UCN-01 in the somewhat more resistant A549 cells), virtually complete growth inhibition of both the cell lines resulted. Supra-additive inhibition of growth was also demonstrated in independent clonogenic assays. Mechanistic studies in cell culture models suggest enhanced depletion of the S-phase population in cells treated by the combination. This correlated with enhanced inactivation of Akt along with activation of caspases 3 and 9 and poly(ADP-ribose) polymerase cleavage. Evidence of synergy was formally demonstrated and occurred across a wide range of drug concentrations and was largely independent of the order or sequence of drug addition. CONCLUSIONS: As the concentrations of UCN-01 and perifosine causing synergistic inhibition of cell growth are clinically achievable without prominent toxicity, these data support the development of clinical studies with this combination.