MS

thesisAlthough much work has been done by many investigators in the study of emphysema, the etiology and the pathogenesis of emphysema are still unknown. Therefore, a study was made to investigate the bacterial flora of patients with emphysema, to see if there was a species or strain of organisms peculiar to emphysema. These bacteria were tested (1) for their ability to multiply in pulmonary mucus in vitro, (2) to examine the surface tension properties of mucus in vitro, and (3) to examine the alteration of surface tension of culture media by microorganisms. Twenty-six patients from the Pulmonary Disease Service of the Veterans Administration Hospital, Salt Lake City, Utah were utilized in this study. An initial selection of patients known to have bronchitis, bronchiectasis, or emphysema and who did not have antibacterial chemotherapy for 6 months were chosen by the Chief of the Pulmonary Disease Service and resident physicians. Most studies of the sputum flora in patients with chronic bronchitis and bronchiectasis are based on bacteriological cultures of expectorated bronchial secretions. Contamination by nasopharyngeal microorganisms is inevitable, since bacteria known to be normal inhabitants of the pharynx are cultured from expectorated sputum. Bacteria isolated in this manner cannot be assumed to have significance in bronchial inflammation. This study was designed to compare qualitatively and quantitatively the bacterial flora of expectorated bronchial secretions and saliva in patients with chronic bronchitis or bronchiectasis, in an effort to assess the importance of contamination of the expectorated bronchial secretion by saliva. A comparison of the numbers of bacteria in saliva and sputum in 26 patients showed that there are tremendous numbers of bacteria in saliva. Even in a clean" mouth, saliva contained as large or larger numbers of bacteria than did expectorated sputum. The presence in both sputum and saliva of alpha hemolytic Streptococci, non-hemolytic Streptococci, the Neisseria species, non-hemolytic Staphylococcus aureus and non-hemolytic and hemolytic St. albus suggests a nasopharyngeal origin of these strains. The D. pneumoniae, hemolytic St. aureus, and the Hemophilus species were less frequently isolated from the sputum suggesting a bronchial origin for these organisms. Besides using the cultural technique for the isolation of D. pneumoniae, white mice were inoculated with saliva and sputum. It was found that animal inoculation yielded more positive isolations than by cultural methods in saliva. However, there was a greater number of isolation of D. pneumoniae by cultural technique from the sputum than by animal inoculation. Sterile sputum was employed as a substrate for the possible growth of bacteria from patients with emphysema, and it was found that some of these bacteria grew well in sputum. The surface tension measurements of sputa and broths were performed before and after incubation with organisms. This investigation has shown that the proliferation of microorganisms in sputum or broth either increased or decreased the surface tension of the sputum or broth depending on the bacteria

Neural activity and new methods of computational analysis in the model of mammalian brain cortex

Analysis of the real brain’s neural activity can be performed in many different ways like forexample electroencephalography. Sometimes the value of neural membrane potential is collectedeven from particular cells, using electrodes in neurophysiological experiments. However, thisinvasive method can be performed only on animals and in most cases leads to death of theexperiment’s subject. Computer modelling and simulation are often very important for the designof real experiments and in this paper we present the set of three new methods of neurodynamicalanalysis, two of them analogical to the probing used in neurophysiology andelectroencephalography. We show that in some cases our approach can be even more effectivethan the techniques used in bio-medical laboratories

The fetal mouse is a sensitive genotoxicity model that exposes lentiviral-associated mutagenesis resulting in liver oncogenesis

This article is available open access through the publisher’s website at the link below. Copyright @ 2013 The American Society of Gene & Cell Therapy.Genotoxicity models are extremely important to assess retroviral vector biosafety before gene therapy. We have developed an in utero model that demonstrates that hepatocellular carcinoma (HCC) development is restricted to mice receiving nonprimate (np) lentiviral vectors (LV) and does not occur when a primate (p) LV is used regardless of woodchuck post-translation regulatory element (WPRE) mutations to prevent truncated X gene expression. Analysis of 839 npLV and 244 pLV integrations in the liver genomes of vector-treated mice revealed clear differences between vector insertions in gene dense regions and highly expressed genes, suggestive of vector preference for insertion or clonal outgrowth. In npLV-associated clonal tumors, 56% of insertions occurred in oncogenes or genes associated with oncogenesis or tumor suppression and surprisingly, most genes examined (11/12) had reduced expression as compared with control livers and tumors. Two examples of vector-inserted genes were the Park 7 oncogene and Uvrag tumor suppressor gene. Both these genes and their known interactive partners had differential expression profiles. Interactive partners were assigned to networks specific to liver disease and HCC via ingenuity pathway analysis. The fetal mouse model not only exposes the genotoxic potential of vectors intended for gene therapy but can also reveal genes associated with liver oncogenesis.Imperial College London, the Wellcome Trust, and Brunel University

MscS-like mechanosensitive channels in plants and microbes

The challenge of osmotic stress is something all living organisms must face as a result of environmental dynamics. Over the past three decades, innovative research and cooperation across disciplines have irrefutably established that cells utilize mechanically gated ion channels to release osmolytes and prevent cell lysis during hypoosmotic stress. Early electrophysiological analysis of the inner membrane of Escherichia coli identified the presence of three distinct mechanosensitive activities. The subsequent discoveries of the genes responsible for two of these activities, the mechanosensitive channels of large (MscL) and small (MscS) conductance, led to the identification of two diverse families of mechanosensitive channels. The latter of these two families, the MscS family, consists of members from bacteria, archaea, fungi, and plants. Genetic and electrophysiological analysis of these family members has provided insight into how organisms use mechanosensitive channels for osmotic regulation in response to changing environmental and developmental circumstances. Furthermore, determining the crystal structure of E. coli MscS and several homologues in several conformational states has contributed to our understanding of the gating mechanisms of these channels. Here we summarize our current knowledge of MscS homologues from all three domains of life and address their structure, proposed physiological functions, electrophysiological behaviors, and topological diversity

Effects of lesions in the medial forebrain bundle and median plus dorsal midbrain raphe nuclei on shock sensitivity and forebrain serotonin

Includes bibliographical references.After rats have been given bilateral medial forebrain bundle lesions (MFB) it has been observed that there is a decrease in forebrain serotonin (5-HT) concentration and an increase in shock sensitivity as measured by a lowered jump threshold. Thus it has been suggested that forebrain 5-HT modulates shock sensitivity. Therefore when the nuclei of origin (median and dorsal midbrain raphe nuclei) of the serotonergic fibers are lesioned, it is reasonable to expect a greater decrease in forebrain 5-HT content and a greater increase in shock sensitivity than that produced by NFB lesions. These results have not been obtained. A lesion in the raphe nuclei produces a decrease in forebrain 5-HT and no effect on shock sensitivity. The possibility that raphe lesions also destroy an algebraically interacting, excitatory pain system has been suggested to account for this effect. The present study examined this possibility by creating NFB and raphe lesions in experimental animals. These animals were then tested by the flinch-jump method. After behavioral testing, a sub-group of MFB-lesioned animals were reoperated to produce a MFB-raphe combined lesion. All the animals were then retested by the flinch-jump method. The animal's brains were then assayed for 5-HT and NE content and the brainstems were checked for lesion extent and location. It was found that lesions of the MFB, dorsal plus median midbrain raphe nuclei and the combined MFB-raphe areas produced significant reductions in forebrain 5-HT and failed to affect flinch thresholds significantly. One sub-group of MFB-lesioned subjects had significantly lowered jump thresholds on the first test but this effect was not replicated in the second test. MFB-raphe combined lesions produced analgesia as indexed by elevated jump thresholds. This elevation occurred in spite of the fact that this sub-group of MFE-lesioned rats did not have a significantly lowered jump threshold on the first test. Although not clear-cut because of the lack of an increase in shock sensitivity following the initial surgery in this sub-group of MFB-lesioned animals, these results suggest that the failure to find increased pain sensitivity following raphe lesions that significantly deplete forebrain 5-HT could be due to the fact that these same lesions are destroying a non-serotonergic, excitatory pain system in this part of the brain.M.S. (Master of Science

The bloom is (slightly) off the rose: the motherhood effect on psychological functioning in successive pregnancies

Objective: To examine the maternal psychological state during the course of two successive pregnancies. Methods: The sample consisted of 73 women drawn from a larger maternal–fetal cohort that participated during two pregnancies. Women completed self-report psychological questionnaires at 24, 30, and 36 weeks gestation to index maternal depressive symptoms, trait anxiety, and pregnancy hassles and uplifts. Analyses examined stability of maternal symptoms across successive pregnancies in the same women. Results: Antenatal symptoms of depression and anxiety exhibited strong intra-individual stability between successive pregnancies. Mean differences in maternal symptoms were not detected for either at 24, 30, or 36 weeks gestation, excepting elevated anxiety symptoms at the mid-point due to greater fluctuation in maternal anxiety during the prior pregnancy. Subsequent pregnancies were associated with less intense uplifting feelings about the pregnancy on each measurement occasion. Conclusions: Findings suggest marked consistency in maternal psychological orientation across subsequent pregnancies, though parity also plays a role in the maternal experience

VapC proteins from Mycobacterium tuberculosis share ribonuclease sequence specificity but differ in regulation and toxicity.

The chromosome of Mycobacterium tuberculosis (Mtb) contains a large number of Type II toxin-antitoxin (TA) systems. The majority of these belong to the VapBC TA family, characterised by the VapC protein consisting of a PIN domain with four conserved acidic residues, and proposed ribonuclease activity. Characterisation of five VapC (VapC1, 19, 27, 29 and 39) proteins from various regions of the Mtb chromosome using a combination of pentaprobe RNA sequences and mass spectrometry revealed a shared ribonuclease sequence-specificity with a preference for UAGG sequences. The TA complex VapBC29 is auto-regulatory and interacts with inverted repeat sequences in the vapBC29 promoter, whereas complexes VapBC1 and VapBC27 display no auto-regulatory properties. The difference in regulation could be due to the different properties of the VapB proteins, all of which belong to different VapB protein families. Regulation of the vapBC29 operon is specific, no cross-talk among Type II TA systems was observed. VapC29 is bacteriostatic when expressed in Mycobacterium smegmatis, whereas VapC1 and VapC27 displayed no toxicity upon expression in M. smegmatis. The shared sequence specificity of the five VapC proteins characterised is intriguing, we propose that the differences observed in regulation and toxicity is the key to understanding the role of these TA systems in the growth and persistence of Mtb