Initial Commitment to Pre-Exposure Prophylaxis and Circumcision for HIV Prevention amongst Indian Truck Drivers

Studies of HIV prevention interventions such as pre-exposure prophylaxis (PREP) and circumcision in India are limited. The present study sought to investigate Indian truck-drivers initial commitment to PREP and circumcision utilizing the AIDS Risk Reduction Model. Ninety truck-drivers completed an in-depth qualitative interview and provided a blood sample for HIV and HSV-2 testing. Truck-drivers exhibited low levels of initial commitment towards PREP and even lower for circumcision. However, potential leverage points for increasing commitment were realized in fear of infecting family rather than self, self-perceptions of risk, and for PREP focusing on cultural beliefs towards medication and physicians. Cost was a major barrier to both HIV prevention interventions. Despite these barriers, our findings suggest that the ARRM may be useful in identifying several leverage points that may be used by peers, health care providers and public health field workers to enhance initial commitment to novel HIV prevention interventions in India.     

Radioimmunoassay of polypeptide hormones using immunochemically coated plastic tubes

A method has been developed for immobilisation of antisera on fresh plastic tubes through an immunochemical bridge. This type of immobilisation has been shown to be more consistent than direct adsorption on plastic. Such immunochemically coated antisera on plastic tube has been used in the development of a noncentrifugation radioimmunoassay. This assay system has been found to be technically as sound as the conventional method.     

Effect of lithium on regulation of two molecular forms of Na+,K(+)-ATPase in rat brain

Effects of lithium in vivo and in vitro on the two molecular forms of Na+,K(+)-ATPase in rat brain were investigated. Inhibition by strophanthidin, affinity to monovalent cations and cellular localization of the enzyme were used to differentiate the two molecular forms. K+ dependent p-nitrophenylphosphatase activity and strophanthidin inhibition studies revealed selective increase in the activity of low affinity form but not high affinity form of the enzyme following lithium treatment. Na+ sensitivity of neither forms of Na+,K(+)-ATPase was changed but K+ sensitivity of low affinity form was increased due to lithium. Lithium showed biphasic effects on low affinity form of the enzyme; activation at low concentration and inhibition at high concentration. The results suggest that lithium in vivo regulates the concentration of extra cellular potassium by selectively acting at K+ site of low affinity form of the enzyme (astroglial) but not on high affinity form (neuronal enzyme) and leading to changes in neuronal depolarization.     

Mitogenic,immunoadjuvancy, and genetic studies on fatty acyl maltose

Summary Three synthetic glycolipids, maltose tetrapalmitate (MTP), maltose hexastearate (MHS), and maltose hexalinoleate (MHL) prepared as nontoxic lipid A analogs, and Escherichia coli lipopolysaccharide (LPS) were assayed for their mitogenic activity using spleen lymphocytes in nine inbred mouse strains and three F1 hybrids. The MTP and LPS were also assayed for their ability to enhance plaque-forming cell (PFC) responses using sheep red blood cells as the antigen in th same inbred mouse strains and F1 hybrids, The mitogenic activity of synthetic glycolipids was several fold lower than that of LPS and MHL was inferior to MTP and MHS. DBA/2J was the most responsive strain for MTP and DBA/1J and C3H/HeJ the least. The mitogenic activity of MTP was generally in agreement with the PFC response stimulation by it. Lowdose cyclophosphamide treatment of mice synergized MTP for PFC response augmentation. Genetic studies on MTP mitogenicity revealed that 90% of responder DBA/2J X nonresponder C3H/HeJ F1 hybrids had intermediate mitogenic activity. Among F2, 73% had intermediate-high activity and 27% were nonmitogenic. Among F1 X C3H/HeJ backcrosses 11% had high, 56% intermediate, and 33% had no mitogenic activity, whereas, for the F1 X DBA/2J backcross, 14% had high, 36% intermediate, and 50% low or negligible activity. The data favored a single gene for MTP activation of immune cells.This work was supported, in part, by a grant from the National Cancer Institute of Canada, and by grant from the Cancer Research Society Inc.     

Effect of methionine-sulfoximine on nitrate uptake and photosynthesis in the cyanobacteriumAnabaena doliolum Bharadwaja

l-Methionine-dl-sulfoximine (MSX) stimulated nitrate uptake but inhibited¹⁴CO₂ fixation and O₂ evolution inAnabaena doliolum. Nitrate uptake was inhibited by ammonium (NH ₄ ⁺ ) in the absence of MSX, but not in the presence of MSX. Glutamine or a derivative of it appears to be the actual negative effector of nitrate utilization. In presence of nitrate, MSX-treated cells ofA. doliolum evolve more O₂ than do untreated cells. Our results suggest a close relation between photoassimilation of carbon and utilization of nitrogen.     

Hybridization of DNA from methanogenic bacteria with nitrogenase structural genes (nifHDK)

Summary Using the Southern hybridization technique, homologies were examined between restricted DNA of four methanogenic bacteria (Methanobacterium ivanovi, Methanobacterium thermoautotrophicum, Methanococcus voltae, Methanosarcina barkeri) and the nif (nitrogen fixation) genes of Klebsiella pneumoniae and Anabaena strain 7120. With K. pneumoniae probes, no hybridization was observed with nifA, nifNE, and nifJ but positive results were obtained with the nifHDK genes coding for nitrogenase. Homology was detected, in the four strains, with K. pneumoniae and Anabaena nifH probes. In M. voltae and M. ivanovi, the homology found with nifH was estimated to be about 70% and a weaker hybridization was observed also with nifD and nifK. In M. voltae, the sequence homologous to nifH was found on a 3.0 kbp HindIII fragment and sequences homologous to nifD and nifK on a 3.8 kbp HindIII fragment. The 3.0 kbp fragment was cloned and the region homologous to nifH was localized more precisely. When this fragment was used as a probe against other DNAs, it behaved as a K. pneumoniae and Anabaena nifH probe. The results suggest that the structural genes for nitrogenase may be present in archaebacteria and raise interesting questions regarding their evolution.     

DNA sequence organization in the genomes of three related millet plant species

Summary A major portion of the genomes of three millet species, namely, barn yard millet, fox tail millet and little millet has been shown to consist of interspersed repeat and single copy DNA sequences. The interspersed repetitive DNA sequences are both short (0.15–1.0 kilo base pairs, 62–64% and long (>1.5 kilo base pairs, 36–38%) in barn yard millet and little millet while in fox tail millet, only long interspersed repeats (>1.5 kilo base pairs) are present. The length of the interspersed single copy DNA sequences varies in the range of 1.6–2.6 kilo base pairs in all the three species. The repetitive duplexes isolated after renaturation of 1.5 kilo base pairs and 20 kilo base pairs long DNA fragments exhibit a high thermal stability with Tms either equal to or greater than the corresponding native DNAs. The S1 nuclease resistant repetitive DNA duplexes also are thermally stable and reveal the presence of only 1–2% sequence divergence.The present data on the modes of sequence arrangement in millets substantiates the proposed trend in plants, namely, plants with 1C nuclear DNA content of less than 5 picograms have diverse patterns of sequence organization while those with 1C nuclear DNA content greater than 5 picograms have predominantly a short period interspersion pattern.Abbreviations kbp kilobase pairs NCL Communication No. 3606.     

Identification and sequence characterization of a 1.3 Kb EcoRI repeat fragment that harbors a DNA repair site of rat pachytene spermatocytes

Introduction of well-programmed nicks and gaps and the associated DNA repair activity in the genome at the pachytene interval is a characteristic feature of the meiotic prophase in organisms as varied as lilium and mouse. In the present study we have shown that the DNA synthetic activity in rat pachytene spermatocytes is insensitive to aphidicolin, a specific inhibitor of DNA polymerase , and , suggesting DNA -polymerase-mediated repair synthesis in these cells. We have developed a novel approach for the isolation of the DNA repair sites by combining two independent techniques. Following incorporation of BrdUrd into pachytene spermatocytes in the presence of aphidicolin, the repair sites were released as ssDNA fragments by treatment of nuclei with 30 mM NaOH. Subsequently, the BrdUrd containing ssDNA fragments were specifically isolated using polyclonal anti-BrdUrd antibodies. The DNA fragments released were of two size classes, namely 4–7S (major) and 9–12S (minor) and constituted approximately 1.75% of the pachytene genomic DNA. These DNA repair fragments were distinct from Okazaki fragments and other replicative intermediates isolated from rat bone marrow cells as evidenced by (a) their different size distribution and (b) little cross-hybridization. Southern hybridization of restriction enzyme digests of rat genomic DNA with probes made against BrdUrd-ssDNA fragments revealed that although the repair sites were distributed throughout the genome, strong hybridization signals were observed in EcoRI, (1.3 kb and 2.4 kb), BamH1 (9 kb) and HindIII (5 kb) repetetive DNA fragments. The EcoRI 1.3 kb family were cloned into M13 mp19, and a repair positive (1.3 A) and a repair negative (1.3 B) were identified and sequenced. The repair positive clone contained (a) (CA)₂₂ repeat, (b) a (CAGA)₆ repeat and (c) 4 sequences sharing high homology with various hypervariable minisatellite (HVMS) sequences. One of the HVMS sequence contained a GGCAGG motif known to be responsible for germline instability. The repair negative clone had (a) (CA)₆ repeat and (b) a HVMS like sequence without GGCAGG. The significance of these motifs and their relevance to the events of DNA metabolism at pachytene interval have been discussed.     

Tetracyclines modulate cytosolic Ca2+ responses in the osteoclast associated with “Ca2+ receptor” activation

We report the effects of tetracycline analogues on cytosolic Ca²⁺ transients resulting from application of ionic nickel (Ni²⁺), a potent surrogate agonist of the osteoclast Ca²⁺ receptor. Preincubation with minocycline (1 mg/l) or a chemically modified tetracycline, 4-dedimethyl-aminotetracycline (CMT-1) (1 or 10 mg/l), resulted in a significant attenuation of the magnitude of the cytosolic [Ca²⁺] response to an application of 5 mM-[Ni²⁺]. Preincubation with doxycycline (1 or 10 mg/l) failed to produce similar results. In addition, application of minocycline alone (0.1–100 mg/l) resulted in a 3.5-fold elevation of cytosolic [Ca²⁺]. The results suggest a novel action of tetracyclines on the osteoclast Ca²⁺ receptor.