Microbiology Commons^™

Kinetic Characterization Of Tetracycline Binding And Release By Demineralized Bone - Dfdba, Orner Kabil

Biological Sciences Theses & Dissertations

The microbial etiology of periodontal diseases has led to widespread research in the development of methods and local delivery systems to increase the efficacy of antibiotic therapy. Several drug delivery systems employing biodegradable and nonbiodegradable carriers have been shown to release antibiotics directly into periodontal pockets. The purpose of this study was to determine the binding and release kinetics of tetracycline by demineralized bone. Further aspects of the study include in vitro evaluation of DFDBA (demineralized freeze-dried bone allografts) as a tetracycline carrier system for periodontal therapy. Experiments were performed which employed different tetracycline concentrations with constant amounts of bone …

Morphological Pattern Of Testicular Tumors, M S. Gill, S H. Shah, I N. Soomro, Naila Kayani, Sheema H. Hasan

Department of Pathology and Laboratory Medicine

Objective:
To find out the mode of presentation, age distribution and the prevalence of various histological subtypes of testicular tumors.
Method:
All consecutive cases of testicular tumors diagnosed in the department of pathology, the Aga Khan University Hospital, Karachi, during the period of eight years (1991-98) were included in this study. Relevant clinical details such as age, clinical presentation and side of involvement of the testis were also recorded, where available.
Results:
During the span of eight years (1991-98), 170 cases of testicular tumors were diagnosed at the Aga Khan University Hospital, Karachi. Most of the tumors were diagnosed in …

Integronlike Structures In Campylobacter Spp. Of Human And Animal Origin, Brigid Lucey, D. Crowley, P. Moloney, B. Cryan, M. Daly, F. O'Halloran, E. J. Threlfall, S. Fanning

Department of Biological Sciences Publications

Resistance to antimicrobial agents used to treat severe Campylobacter spp. gastroenteritis is increasing worldwide. We assessed the antimicrobial resistance patterns of Campylobacter spp. isolates of human and animal origin. More than half (n = 32) were resistant to sulphonamide, a feature known to be associated with the presence of integrons. Analysis of these integrons will further our understanding of Campylobacter spp. epidemiology.

Identification Of The Transactivation Domain Of The Transcription Factor Sox-2 And An Associated Co-Activator, Tamara K. Nowling, Lance R. Johnson, Matthew S. Wiebe, Angie Rizzino

Nebraska Center for Virology: Faculty Publications

The importance of interactions between Sox and POU transcription factors in the regulation of gene expression is becoming increasingly apparent. Recently, many examples of the involvement of Sox-POU partnerships in transcription have been discovered, including a partnership between Sox-2 and Oct-3. Little is known about the mechanisms by which these factors modulate transcription. To better understand the molecular interactions involved, we mapped the location of the transactivation do-main of Sox-2. This was done in the context of its interaction with Oct-3, as well as its ability to transactivate as a fusion protein linked to the DNA-binding domain of Gal4. Both …

Quantitative Image Analysis Of Simian Immunodeficiency Virus Replication In Macrophages Coinfected With Mycobacterium Avium Complex, Qingsheng Li, Keith G. Mansfield, Andrew Lackner, Ashley T. Haase

Qingsheng Li Publications

Mycobacterium avium is the most frequent cause of disseminated bacterial infection in patients with human immunodeficiency virus type 1 infection and in rhesus macaques with simian immunodeficiency virus (SIV) infection. This animal model of AIDS was used to test the hypothesis that this frequent association is the result of reciprocal enhancement of replication of both microorganisms. The replication of M. avium and SIV was analyzed in lymphatic tissues obtained from rhesus macaques experimentally inoculated with SIVmac who developed or remained free of overt M. avium infection. In situ hybridization, quantitative image analysis, and staining of M. avium and of macrophages …

Risk Of Imported Filariasis In Pakistan, M A. Beg

Department of Pathology and Laboratory Medicine

No abstract provided.

The Global Carbon Metabolism Regulator Crc Is A Component Of A Signal Transduction Pathway Required For Biofilm Development By Pseudomonas Aeruginosa, George A. O'Toole, Karine A. Gibbs, Paul W. Hager, Paul V. Phibbs, Roberto Kolter

Dartmouth Scholarship

The transition from a planktonic (free-swimming) existence to growth attached to a surface in a biofilm occurs in response to environmental factors, including the availability of nutrients. We show that the catabolite repression control (Crc) protein, which plays a role in the regulation of carbon metabolism, is necessary for biofilm formation in Pseudomonas aeruginosa. Using phase-contrast microscopy, we found that a crc mutant only makes a dispersed monolayer of cells on a plastic surface but does not develop the dense monolayer punctuated by microcolonies typical of the wild-type strain. This is a phenotype identical to that observed in mutants …

The Molecular Epidemiology Of Rotavirus In Ireland, Fiona O'Halloran

Theses

Between 1997 and 1998, 3,136 cases of rotavirus diarrhoea were detected in Irish children less than 2 years of age. Hospital inpatients accounted for 80% of these infections, with the remainder being diagnosed in general practice. A large percentage of infections were detected in neonates, suggesting a possible inadequate maternal derived protection from existing indigenous strains. This feature suggested the possible existence of ‘novel’ strains circulating in Ireland. No data describing the epidemiology of rotavirus strains in this country currently exists. Furthermore no assessment of the potential health-economic impact or quantitation of potential disease burden was ever undertaken

Three hundred …

A Preclinical Model Of Ionizing Radiation And Tnf-Alpha Gene Therapy For Cancer, Jun Li

Loma Linda University Electronic Theses, Dissertations & Projects

Long term control of high-grade brain tumors is rarely achieved with current therapeutic regimens. This study sought to determine if pretreatment with plasmid DNA expressing Tumor Necrosis Factor-α (TNF-α) could enhance the effect of ionizing radiation in an aggressive, rapidly growing glioma tumor (C6) model. Plasmid DNA is an attractive vector system for delivery of foreign genes into eukaryotic cells due to its advantages including low immunogenicity in vivo, lesser toxicity and relatively low cost. We have constructed a plasmid-based mammalian expression vector (pGL1-TNF) to secrete human TNF-α from cancer cells. Plasmid DNA was successfully transfected into C6 cells …

Arthritis And Rosai-Dorfman Disease Of The Skin: A Diagnostic Dilemma, Irshad Nabi Soomro, Kamran Hameed

Department of Pathology and Laboratory Medicine

No abstract provided.

P53 And Pcna Expression In Benign, Atypical And Malignant Meningiomas, R Ahmed, I N. Soomro, S A. Aziz, S H. Hasan

Department of Pathology and Laboratory Medicine

Objective: Alterations: p53 genes are turning out to be the most common genetic alterations in human cancers. Due to long half-life of mutated p53, its detection is possible by immunohistochemistry. Proliferating cell nuclear antigen (PCNA) is expressed by dividing cells, hence has been shown to correlate with prognosis. We have used monoclonal antibodies protein DO-7 (p53) and PC10 (PCNA) to see whether their expression correlates with histological grading in meningethelial tumour.
Material and Methods: a Twenty nine meningiomas (20 benign, 7 atypical and 2 malignant) were selected from the records of our laboratory. p53 and PCNA expression was sought by …

Spinal Cord Compression Caused By Metastatic Epithelial Myoepithelial Carcinoma Of The Parotid Gland, I N. Soomro, A S. Hussainy, K Chishti, M H. Pui, S A. Khan, R Ahmed, S H. Hasan

Department of Pathology and Laboratory Medicine

No abstract provided.

A Study On The Effects Of The N-Terminal Amino Acid Sequence On The Activation Of Human T-Cell Leukemia Virus Type 1 Protease, Hidayah Muhammad Kendall

Chemistry & Biochemistry Theses & Dissertations

Human T-cell leukemia virus type 1 (HTL V-1) is dependent upon the enzymatic activity of its protease for maturation. Maturation of the protease is facilitated by cleavage of specific amino acid residues, followed by dimerization. The effects of the amino acid sequence located N-terminally to the cleavage site on the ability of the protease to become active were the focus of the current study. These amino acid sequences were contributed by the plasmid vector into which the protease gene was inserted.

Surface probability analyses (SPAs) of the vectors, as well as for native sequences which produce the mature protease and …

Genetic And Structural Analyses Of Cytoplasmic Filaments Of Wild-Type Treponema Phagedenis And A Flagellar Filament-Deficient Mutant, Jacques Izard, William A. Samsonoff, Mary Beth Kinoshita, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

Unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. Their function is unknown, but their location underneath the periplasmic flagellar filaments (PFF) suggests a role in motility and/or cell structure. To better understand these unique structures, the gene coding for the cytoplasmic filaments, cfpA, was identified in various treponemal species. Treponema phagedenis cfpA was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence identity with the partial sequence of CfpA from T. denticola, T. vincentii, and T. pallidum subsp. pertenue. Wild-type T. phagedenis and a …

An Extracellular Protein Produced By Staphylococcus Hominis Strain Αm With Antimicrobial Activity Against Mycobacterium Spp, Sandra May Jacobsen

Biological Sciences Theses & Dissertations

The inhibitory activity exhibited by Staphylococcus hominis strain αM toward Mycobacterium species was examined. These studies included determining the conditions that maximized inhibitory agent production, analyzing characteristics of the agent, determining the time of agent production, ascertaining plasmid possession and the role of plasmids in the production of this inhibitory agent, and ascertaining the antimicrobial activity of other strains of S. hominis. On solid and in liquid media, S. hominis strain αM exhibits a unique inhibitory activity toward Mycobacterium species that is not demonstrated by Staphylococcus epidermidis or other S. hominis strains. Maximum agent production and recovery was …

A Vibrio Cholerae Lysr Homolog, Aphb, Cooperates With Apha At The Tcpph Promoter To Activate Expression Of The Toxr Virulence Cascade, Gabriela Kovacikova, Karen Skorupski

Dartmouth Scholarship

We describe here a new member of the LysR family of transcriptional regulators, AphB, which is required for activation of the Vibrio cholerae ToxR virulence cascade. AphB activates the transcription of the tcpPH operon in response to environmental stimuli, and this process requires cooperation with a second protein, AphA. The expression of neither aphA or aphB is strongly regulated by environmental stimuli, raising the possibility that the activities of the proteins themselves may be influenced under various conditions. Strains of the El Tor biotype of V. cholerae typically exhibit lower expression of ToxR-regulated virulence genes in vitro than classical strains …

Insertional Inactivation Of Treponema Denticola Tap1 Results In A Nonmotile Mutant With Elongated Flagellar Hooks, Ronald J. Limberger, Linda L. Slivienski, Jacques Izard, William A. Samsonoff

Department of Food Science and Technology: Faculty Publications

The treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. A recently developed system to generate specific mutants in Treponema denticola was utilized to determine if Tap1 was essential for motility. T. denticola tap1 and flanking DNA were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermF and ermAM) was constructed. Because of potential polar effects from this cassette, a second plasmid that contained tap1 interrupted with a modified erythromycin resistance cassette that lacked the putative ermF transcription …

Antitumor Effect Of Il-2, P53, And Bax Naked Gene Transfer In C6 Glioma Cells, Peyman Haghighat

Loma Linda University Electronic Theses, Dissertations & Projects

[Abstract not included]

Dna-Dna Checkerboard Hybridization To Identify Bacteria In Human Plaque Samples, Jasan Lee Zimmerman

Loma Linda University Electronic Theses, Dissertations & Projects

Previous research has shown that using DNA probes to identify the presence of specific bacteria in human plaque samples is superior to the commonly used anaerobic cultural procedures. Some periodontal pathogens are either uncultivable or very difficult to grow, such as Prevotella intermedia, P. nigrescens, and Eubacterium brachy. Digoxygenin probes were prepared for 15 oral bacteria. These probes were used with a checkerboard DNA-DNA hybridization scheme to analyze whether human plaque samples contained any of the 15 bacterial species. Our results have shown that this method is successful in identifying bacterial DNA present in the subgingival patient plaque …

Morphological Pattern And Frequency Of Thyroid Tumors, S H. Shah, S Muzaffar, I N. Soomro, Sheema H. Hasan

Department of Pathology and Laboratory Medicine

Objective:
The present study was done to evaluate the frequency of thyroid cancer and to find out the prevalence of histological types of thyroid tumor with respect to age and sex group.
Setting:
This study included consecutive cases of malignant tumors of thyroid gland, which were diagnosed in the Department of Pathology at the Aga Khan University Hospital, Karachi during the period of three years (1995-1997).
Methods:
These cases were evaluated on H & E stained sections from paraffin embedded 10% buffered formalin fixed tissue blocks. Special stains and immunohistochemical analysis were performed whenever required.Results: A total of 8541 malignant …

Clinico-Morphological Pattern Of Intracranial Tumors In Children, Sajid H. Shah, Irshad N. Soomro, Akbar S. Hussainy, S H. Hassan

Department of Pathology and Laboratory Medicine

Objective:
The objective of present study was to observe the histopathological pattern of intracranial tumors in children (< 15 yrs) and to correlate the site of lesion along with the histological diagnosis.
Setting:
The study included consecutive cases of intracranial tumors diagnosed in children (< 15 yrs.) in the section of histopathology at the Aga Khan University Hospital, Karachi during the period of three years.
Methods:
The initial histological evaluation of these lesions was performed on H and E stained section of paraffin embedded tissue. Special stains and immunohistochemical analysis was done whenever indicated.
Results:
During the study period, fifty-four cases of intracranial tumors were diagnosed in children. The age ranged from 1-1/2 years to 4 years with male to female ratio of 1.1:1. Astrocytoma comprised 39% of all intracranial tumors of childhood. Medulloblastoma …

Genetic And Transcriptional Analyses Of The Vibrio Cholerae Mannose-Sensitive Hemagglutinin Type 4 Pilus Gene Locus, Jane W. Marsh, Ronald K. Taylor

Dartmouth Scholarship

The mannose-sensitive hemagglutinin (MSHA) of the Vibrio cholerae O1 El Tor biotype is a member of the family of type 4 pili. Type 4 pili are found on the surface of a variety of gram-negative bacteria and have demonstrated importance as host colonization factors, bacteriophage receptors, and mediators of DNA transfer. The gene locus required for the assembly and secretion of the MSHA pilus has been localized to a 16.7-kb region of the V. cholerae chromosome. Sixteen genes required for hemagglutination, including five that encode prepilin or prepilin-like proteins, have been identified. Examination of MSHA-specific cDNAs has localized two promoters …

Identification And Characterization Of Spcu, A Chaperone Required For Efficient Secretion Of The Exou Cytotoxin, Viviane Finck-Barbançon, Timothy L. Yahr, Dara W. Frank

Dartmouth Scholarship

In recent studies, we have shown that Pseudomonas aeruginosa strains that are acutely cytotoxic in vitro damage the lung epithelium in vivo. Genetic analysis indicated that the factor responsible for acute cytotoxicity was controlled by ExsA and therefore was part of the exoenzyme S regulon. The specific virulence determinant responsible for epithelial damage in vivo and cytotoxicity in vitro was subsequently mapped to the exoU locus. The present studies are focused on a genetic characterization of the exoU locus. Northern blot analyses and complementation experiments indicated that a region downstream of exoU was expressed and that the expression of this …

The Seca Subunit Of Escherichia Coli Preprotein Translocase Is Exposed To The Periplasm, Jerry Eichler, William Wickner

Dartmouth Scholarship

SecA undergoes conformational changes during translocation, inserting domains into and across the membrane or enhancing the protease resistance of these domains. We now show that some SecA bound at SecYEG is accessible from the periplasm to a membrane-impermeant probe in cells with a permeabilized outer membrane but an intact plasma membrane.

Influence Of The Ccr2-V64i Polymorphism On Human Immunodeficiency Virus Type 1 Coreceptor Activity And On Chemokine Receptor Function Of Ccr2b, Ccr3, Ccr5, And Cxcr4, Benhur Lee, Benjamin J. Doranz, Shalini Rana, Yanji Yi, Mario Mellado, Jose M. R. Frade, Carlos Martinez-A., Stephen J. O'Brien, Michael Dean, Ronald G. Collman, Robert W. Doms

Biology Faculty Articles

The chemokine receptors CCR5 and CXCR4 are used by human immunodeficiency virus type 1 (HIV-1) in conjunction with CD4 to infect cells. In addition, some virus strains can use alternative chemokine receptors, including CCR2b and CCR3, for infection. A polymorphism in CCR2 (CCR2-V64I) is associated with a 2- to 4-year delay in the progression to AIDS. To investigate the mechanism of this protective effect, we studied the expression of CCR2b and CCR2b-V64I, their chemokine and HIV-1 coreceptor activities, and their effects on the expression and receptor activities of the major HIV-1 coreceptors. CCR2b and CCR2b-V64I were expressed at …

Characterization Of Metal-Regulated Genes In Pseudomonas Fluorescens, Melanie Pearson

Honors Theses

One side effect of today's industrialized world is increased levels of heavy metals in the environment. Many of these metals are necessary for biological function as trace elements, but at higher concentrations are toxic. Other metals, such as cadmium, are not beneficial at any level, and have only deleterious effects on living organisms. Cadmium is primarily thought to interfere with normal biological function of proteins. Human exposure to cadmium appears to primarily damage the kidneys, but may also affect the liver, lungs, immune system, and central nervous system. Bacteria, however, have developed several methods for handling toxic heavy metals: cation …

Detection Of Mycobacterium Tuberculosis In Paraffin Embedded Intestinal Tissue Specimens By Polymerase Chain Reaction: Characterization Of Is6110 Element Negative Strains, Tariq Moatter, Shaper Mirza, Mohammad Shahid Siddiqui, Irshad Nabi Soomro

Department of Pathology and Laboratory Medicine

Tuberculosis is still one of the most widespread infection known to mankind. Although lung is the predominant site of disease, a sizeable population in Pakistan gets intestinal disease. Clinical presentation, radiologic and endoscopic examination provide clues to the diagnosis. However, a definitive diagnosis requires biopsy material with granulomas and/or caseation complemented by acid fast staining and culture. There are many occasions when biopsy material is scanty and even in some intestinal resection cases histologic evaluation fails to confirm or rule out tuberculosis. Therefore, an investigation was conducted to assess the efficacy of PCR in the detection of mycobacterial DNA in …

Predicting Prognosis In Lung Cancer: Use Of Proliferation Marker, Ki67 Monoclonal Antibody, I N. Soomro, J Holmes, W F. Whimster

Department of Pathology and Laboratory Medicine

An investigation was carried out to assess the prognostic significance of proliferation marker Ki67 in a group of lung cancer patients treated by surgery (limited disease). Tissue was not available for Ki67 immunostaining in inoperable group. The diagnosis is established by bronchial biopsy which does not carry enough tissue for frozen section and counting. This study is supplemented by estimating the prognostic significance of histological sub-types in the operable group and in a group of inoperable patients with extensive disease. These are usually treated by radiotherapy and/or chemotherapy. In all, 267 patients were studied including 105 treated by surgery. These …

Direct Demonstration Of Retroviral Recombination In A Rhesus Monkey, Dawn P. Wooley, Randall A. Smith, Susan Czajak, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

Recombination may be an important mechanism for increasing variation in retroviral populations. Retroviral recombination has been demonstrated in tissue culture systems by artificially creating doubly infected cells. Evidence for retroviral recombination in vivo is indirect and is based principally on the identification of apparently mosaic human immunodeficiency virus type 1 genomes from phylogenetic analyses of viral sequences. We infected a rhesus monkey with two different molecularly cloned strains of simian immunodeficiency virus. One strain of virus had a deletion in vpx and vpr, and the other strain had a deletion in nef. Each strain on its own induced low virus …

Mucinous Cystadenoma Of The Urinary Bladder, I N. Soomro, A T. Rashid

Department of Pathology and Laboratory Medicine

No abstract provided.