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Biomedical subjects

J K Olson

Publications and source records attributed to J K Olson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Chrysomya rufifacies (Macquart) as a forensically-important fly species in Thailand: a case report.

The first documented use of the larvae of the hairy maggot blow fly, Chrysomya rufifacies, for estimating the postmortem interval (PMI) of a decomposing human corpse in Thailand is reported. A honeycomb-like wound observed on one leg of the corpse was infested with numerous third-stage C. rufifacies larvae. Based on the pupae and larvae present in accordance with the ambient temperature previously recorded, six days postmortem was estimated for a corpse at the time of its discovery and investigation. Since adult C. rufifacies specimens have been collected in many parts of both urban and mountainous areas in Thailand, more biological information about this blowfly species is needed to increase the accuracy of forensic investigations where the fly is present.

Adult↗
PubMed2001

Surface ultrastructure of the third-instar larvae of Hydrotaea spinigera Stein (Diptera: Muscidae), a fly species of forensic importance.

The surface ultrastructure of third-instar larvae of Hydrotaea (= Ophyra) spinigera Stein was observed with scanning electron microscopy. The number of papillae in each anterior spiracle ranges from 5-7. Abdominal segments 4-12 possess ventral welts. Each posterior spiracular disc bears 3 nearly straight slits, with the lower and middle slits closer together than the middle and upper slits. Although the larvae of H. spinigera are generally similar to two other closely-related species in Thailand, Hydrotaea (= Ophyra) leucostoma (Wiedemann) and Hydrotaea (= Ophyra) chalcogaster (Wiedemann), some of the morphological features can help in differentiating these species, thus allowing more accurate identification of species of fly larvae in forensic investigation.

Animals↗
PubMed2000

Temporal development of autoreactive Th1 responses and endogenous presentation of self myelin epitopes by central nervous system-resident APCs in Theiler's virus-infected mice.

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a chronic-progressive, immune-mediated CNS demyelinating disease and a relevant model of multiple sclerosis. Myelin destruction is initiated by TMEV-specific CD4(+) T cells targeting persistently infected CNS-resident APCs leading to activation of myelin epitope-specific CD4(+) T cells via epitope spreading. We examined the temporal development of virus- and myelin-specific T cell responses and acquisition of virus and myelin epitopes by CNS-resident APCs during the chronic disease course. CD4(+) T cell responses to virus epitopes arise within 1 wk after infection and persist over a >300-day period. In contrast, myelin-specific T cell responses are first apparent approximately 50-60 days postinfection, appear in an ordered progression associated with their relative encephalitogenic dominance, and also persist. Consistent with disease initiation by virus-specific CD4(+) T cells, CNS mononuclear cells from TMEV-infected SJL mice endogenously process and present virus epitopes throughout the disease course, while myelin epitopes are presented only after initiation of myelin damage (>50-60 days postinfection). Activated F4/80(+) APCs expressing high levels of MHC class II and B7 costimulatory molecules and ingested myelin debris chronically accumulate in the CNS. These results suggest a process of autoimmune induction in which virus-specific T cell-mediated bystander myelin destruction leads to the recruitment and activation of infiltrating and CNS-resident APCs that process and present endogenous myelin epitopes to autoreactive T cells in a hierarchical order.

Amino Acid Sequence↗
PubMed1998

Taxol hypersensitivity: rapid retreatment is safe and cost effective.

OBJECTIVE: The aim of this study was to describe a rapid retreatment strategy that is safe and cost effective in ovarian cancer patients with Taxol hypersensitivity reactions. METHODS: A retrospective review of 91 women receiving Taxol-based chemotherapy at the University of Iowa Hospitals and Clinics between October 1991 and July 1996 was performed. All patients who developed hypersensitivity reactions to Taxol were identified and their treatment course and outcome were reviewed. RESULTS: Seven women (7.7%) developed hypersensitivity reactions. All received standard premedications consisting of corticosteroids and histamine blockers. Six of the seven were rechallenged with the original Taxol solution starting at a slower rate. In these cases the infusion was completed within 24 h and none of these patients had a reaction in subsequent courses. One patient was not retreated due to the severity of her reaction during a 3-h infusion. CONCLUSION: Retreatment with the original Taxol solution is safe and cost effective in most patients with hypersensitivity reactions. Retreatment with Taxol should be completed within 24 h. A schema for retreatment is presented.

Adrenal Cortex Hormones↗
PubMed1998

Isolation and immunocytochemical characterization of three tachykinin-related peptides from the mosquito, Culex salinarius.

Three myotropic peptides belonging to the Arg-amide insect tachykinin family were isolated from whole-body extracts of the mosquito, Culex salinarius. The peptides, APSGFMGMR-NH2, APYGFTGMR-NH2 and APSGFFGMR-NH2 (designated culetachykinin I, II, and III) were isolated and purified on the basis of their ability to stimulate muscle contractions of isolated Leucophaea maderae hindgut. Biologically inactive methionine sulfoxides of two of the three peptides were isolated using an ELISA system based upon antiserum raised against APYGFTGMR-NH2 and identified with mass spectrometry. Immunocytochemistry localized these peptides in cells in the brain, antennae, subesophageal, thoracic and abdominal ganglion, proventriculus and midgut. Nerve tracts containing these peptides were found in the median nerve of the brain, central body, nervi corpus cardiaci, cervical nerve, antennal lobe and on the surface of the midgut.

Amino Acid Sequence↗
PubMed1998

Varicella-zoster virus glycoprotein gE: endocytosis and trafficking of the Fc receptor.

Varicella-zoster virus (VZV) encodes a functional cell membrane Fc receptor called glycoprotein gE. VZV gE resembles other mammalian cell membrane receptors, such as the mammalian Fc receptor. In further analyses by transient transfection, the cellular trafficking of VZV gE was compared to other cell surface receptors. VZV gE was shown to undergo endocytosis from the cell membrane when visualized by laser scanning confocal microscopy. The endocytosis and trafficking pathway of VZV gE followed closely the pathway defined for the human transferrin receptor. Receptor-mediated endocytosis of VZV gE was dependent on a YAGL motif in its cytoplasmic tail. In addition, VZV gE underwent receptor-mediated endocytosis when it bound the Fc portion of immunoglobulin. Thus, this detailed study of VZV gE cellular trafficking has revealed potential roles for gE during viral infection.

Amino Acid Sequence↗
PubMed1998

Complex formation facilitates endocytosis of the varicella-zoster virus gE:gI Fc receptor.

Open reading frames within the unique short segment of alphaherpesvirus genomes participate in egress and cell-to-cell spread. The case of varicella-zoster virus (VZV) is of particular interest not only because the virus is highly cell associated but also because its most prominent cell surface protein, gE, bears semblance to the mammalian Fc receptor Fc gammaRII. A previous study demonstrated that when expressed alone in cells, VZV gE was endocytosed from the cell surface through a tyrosine localization motif in its cytoplasmic tail (J. K. Olson and C. Grose, J. Virol. 71:4042-4054, 1997). Since VZV gE is normally found in association with gI in the infected cell, the present study was directed at defining the trafficking of the VZV gE:gI protein complex. First, VZV gI underwent endocytosis and recycling when it was expressed alone in cells, and interestingly, VZV gI contained a methionine-leucine internalization motif in its cytoplasmic tail. Second, VZV gI was found by confocal microscopy to colocalize with VZV gE during endocytosis and recycling in cells. Third, by a quantitative internalization assay, VZV gE:gI was shown to undergo endocytosis more efficiently (steady state, 55 to 60%) than either gE alone (steady state, approximately 32%) or gI alone (steady state, approximately 45%). Further, examination of endocytosis-deficient mutant proteins demonstrated that VZV gI exerted a more pronounced effect than gE on internalization of the complex. Most importantly, therefore, these studies suggest that VZV gI behaves as an accessory component by facilitating the endocytosis of the major constituent gE and thereby modulating the trafficking of the entire cell surface gE:gI Fc receptor complex.

Capsid↗
PubMed1998

Organophosphate and pyrethroid susceptibilities of Culex salinarius adults from Texas and New Jersey.

Susceptibilities of adults from newly established colonies of Culex salinarius from New Jersey and Texas to commonly used mosquito adulticides were assessed using the insecticide-coated vial bioassay technique. Females from both colonies were similar in their susceptibilities to naled, chlorpyrifos, resmethrin, and permethrin. However, females from the New Jersey colony (established from collections made in Cape May County, NJ) were found to be 9 times more tolerant to malathion than were those from the Texas colony (established from collections made in Chambers County, TX), with median lethal concentration values for malathion tested against these 2 colonies of 0.70 and 0.08 microgram malathion/vial, respectively. The differences between these 2 colonies with respect to their tolerances to malathion may be a product of the age of each colony at the time assessments were made and/or the degree to which the parent stock used to start each colony was previously exposed to malathion in the field.

Animals↗
PubMed1998

Chorionic morphology of eggs of the Psorophora confinnis complex in the United States. II. Pre- and postdeposition studies of Psorophora Columbiae (Dyar and Knab) eggs.

Scanning and transmission electron microscopic techniques were used to determine the morphology of the exochorion and endochorion of Psorophora columbiae eggs as found in the ovary and after deposition. In the ovary, the outer chorionic reticulations and tubercles of the eggs are ornately developed below the follicular epithelium. Expansion of the eggs after deposition causes the outer chorionic reticuli and sculpturing (i.e., minor and major tubercles) to form the characteristic spinose appearance of Psorophora eggs. Transmission electron microscopic micrographs of cross and sagittal sections of the chorionic layers of Ps. columbiae eggs indicate that the major outer chorionic tubercles have 3 distinct regions. The 3rd region was found only on the dorsum of the tubercle. Elevation of major tubercles appears to be regulated, at least in part, by ambient moisture conditions, and one function of these tubercles seems to be adhesion of the egg to an oviposition surface.

Animals↗
PubMed1998

A geographic information system approach to evaluating the effects of the endangered species protection program on mosquito control.

The purpose of this study was to assess what impacts on organized mosquito control the implementation of an Endangered Species Protection Program for the Houston toad might have in Chambers and Harris counties, Texas. The study was also intended to demonstrate the value of using geographic information system (GIS) techniques and methodologies in making such assessments to those in mosquito control who are unfamiliar with GIS and its applications. Using the GIS, Geographical Analysis Support System (GRASS), databases were developed on the habitats and patterns of mosquito control insecticide usage occurring in Chambers and Harris counties. These databases were then employed by means of various utilities associated with GRASS and computer-supported, rule-based reasoning processes to create maps depicting the amount and locations of toad habitat and the areas treated annually with insecticides by districts in Chambers and Harris counties. This map information was then used via other GRASS utilities to identify and depict zones of overlap or coincidence between toad habitat and areas treated with insecticides for mosquito control in the 2 counties. As compared to existing maps for toad habitat, our resulting GIS-generated maps gave more precise, easy-to-use information that could be used to make decisions as to how to protect the toad in the zones of coincidence in each county without causing undue disruption to mosquito control activities in these zones.

Animals↗
PubMed1998

Educating parish nurses.

During the early 1980s, as government health care reimbursement systems changed in the United States, an interest developed in strengthening healing alliances between health care facilities and faith communities. At the same time, Reverend Granger Westberg recognized the untapped resources of professional nurses that could be made available to parishioners. This recognition led to Westberg's pioneering of parish nursing as a way for faith communities to reclaim their healing mission. The value of reconnecting nurses to their traditional roots in faith communities spread quickly across the United States, and there are now over 3,000 registered nurses practising within American faith communities.

Alberta↗
PubMed1997

Varicella-zoster virus Fc receptor gE glycoprotein: serine/threonine and tyrosine phosphorylation of monomeric and dimeric forms.

Varicella-zoster virus (VZV) glycoprotein gE is the predominant viral cell surface molecule; it behaves as an Fc receptor for immunoglobulin G, but its central function may be more closely related to viral egress and cell-to-cell spread. To further analyze the receptor properties of VZV gE, the gE gene (also called open reading frame 68) was expressed by a baculovirus vector in insect cells. The recombinant baculovirus gE product had a molecular mass of 64 kDa, smaller than the previously documented 98 kDa of mature gE expressed in mammalian cells. The major reason for the lowered molecular mass was diminished glycosylation. In addition to the 64-kDa form, a larger (130-kDa) form was observed in insect cells and represented dimerized 64-kDa molecules. Both the monomeric and dimeric gE forms were highly phosphorylated in insect cells. Protein kinase assays conducted in vitro with [gamma-32P]ATP and [gamma-32P]GTP indicated that endogenous casein kinase II was phosphorylating monomeric gE, while the dimeric gE form was phosphorylated by another kinase which did not utilize [gamma-32P]GTP. When immobilized recombinant gE molecules were probed with a monoclonal antibody which specifically recognizes a phosphotyrosine linkage, the gE dimer was found to be tyrosine phosphorylated whereas the monomer was not similarly modified. When recombinant gE produced in HeLa cells was probed with the same antiphosphotyrosine antibody, a dimeric gE form at 130 kDa was detected on the cell surface. These results suggested that VZV gE closely resembled other cell surface receptors, being modified on its various forms by both serine/threonine and tyrosine protein kinases. In this case, tyrosine phosphorylation occurred on a previously unrecognized and underglycosylated VZV gE dimeric product.

Animals↗
PubMed1997

Endocytosis and recycling of varicella-zoster virus Fc receptor glycoprotein gE: internalization mediated by a YXXL motif in the cytoplasmic tail.

Varicella-zoster virus (VZV) encodes a cell surface Fc receptor, glycoprotein gE. VZV gE has previously been shown to display several features common to nonviral cell surface receptors. Most recently, VZV gE was reported to be tyrosine phosphorylated on a dimeric form (J. K. Olson, G. A. Bishop, and C. Grose, J. Virol. 71:110-119, 1997). Thereafter, attention focused on the ability of VZV gE to undergo receptor-mediated endocytosis. The current transient transfection studies demonstrated by confocal microscopy and internalization assays that VZV gE was endocytosed when expressed in HeLa cells. Endocytosis of gE was shown to be dependent on clathrin-coated vesicle formation within the cells. Subsequent colocalization studies showed that endocytosis of VZV gE closely mimicked endocytosis of the transferrin receptor. The gE cytoplasmic tail and more specifically tyrosine residue 582 were determined by mutagenesis studies to be important for efficient internalization of the protein; this tyrosine residue is part of a conserved YXXL motif. The amount of gE internalized at any given time reached a steady state of 32%. In addition, like the transferrin receptor, internalized gE recycled to the cell surface. The finding of gE endocytosis provided insight into earlier documentation of gE serine/threonine and tyrosine phosphorylation, since these phosphorylation events may serve as sorting signals for internalized receptors. Taken together with the previous discovery that both human and simian immunodeficiency virus envelope proteins can undergo endocytosis, the gE findings suggest that endocytosis of envelope components may be a posttranslational regulatory mechanism among divergent families of enveloped viruses.

Clathrin↗
PubMed1997

Effects of sample handling on total carbon dioxide concentrations in canine and feline serum and blood.

OBJECTIVE: To determine whether underfilling blood collection tubes leads to in vitro reduction in serum measured total CO2 concentration ([TCO2]m) in canine and feline blood samples sufficient to create the impression of metabolic acidosis (pseudometabolic acidosis) or high anion gap. SAMPLE POPULATION: Blood samples from healthy client-owned animals (16 dogs, 17 cats). PROCEDURE: Venous blood samples were collected in random order for determination of serum [TCO2] and blood gas tensions. Blood gas analysis was performed on iced, capped blood samples. In dogs, serum [TCO2] was measured in 1-, 3-, and 10-ml samples in 10-ml type-B tubes and in a 3-ml sample in 3-ml type-A tubes. In cats, serum [TCO2] was determined in 1-, 2-, and 3-ml samples in 3-ml type-A tubes and in a 3-ml sample in 10-ml type-B tubes. RESULTS: For dogs, serum [TCO2] in full-tube, 10-ml samples was a mean +/- SD, 2.0 +/- 1.1 mmol/L greater than that in 3-ml samples and 3.7 +/- 1.3 mmol/L greater than the value in 1-ml samples; both differences were significant at P < 0.0001. The serum [TCO2] in full 3-ml samples was lower by 0.4 +/- 0.6 mmol/L than the value in full-tube 10-ml samples (P = 0.019). For cats, serum [TCO2] in full-tube, 3-ml samples was 0.5 +/- 0.6 mmol/L greater than that in 2-ml samples (P = 0.004) and was 1.5 +/- 0.8 mmol/L greater than the value in 1-ml samples (P < 0.0001). Serum [TCO2] in 3-ml samples of feline blood in 10-ml tubes was 0.8 +/- 0.8 mmol/L lower than that in samples from full 3-ml tubes (P = 0.0007). In dogs and cats, [TCO2] in fully filled collection tubes was approximately 6 mmol/L higher when calculated from blood gas analysis data than when chemically determined in serum. CONCLUSIONS AND CLINICAL RELEVANCE: Underfilling blood collection tubes results in a false decrease in serum [TCO2], which can contribute in part to descrepancies between blood gas and chemical analyses as estimates of plasma bicarbonate concentration. This, and other in vitro effects of sample handling and collection, may result in a false assessment of metabolic acidosis in dogs and cats.

Acidosis↗