Maryland Shared Open Access Repository
MD-SOAR is a shared digital repository platform for twelve colleges and universities in Maryland. It is currently funded by the University System of Maryland and Affiliated Institutions (USMAI) Library Consortium (usmai.org) and other participating partner institutions. MD-SOAR is jointly governed by all participating libraries, who have agreed to share policies and practices that are necessary and appropriate for the shared platform. Within this broad framework, each library provides customized repository services and collections that meet local institutional needs. Please follow the links below to learn more about each library's repository services and collections.
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Item type: Item , Evaluation of Hemostatic Changes in Wistar-Furth and Lewis Rats Infected with Rift Valley Fever Virus Strain ZH501(1995-04) Thureen, Dean R.; Hood College Biology; Biomedical and Environmental ScienceRift Valley Fever virus (RVFV) is a member of the genus Phlebovirus, family Bunyaviridae. Members of this family are characterized by a tripartite, negative sense RNA genome with potential for genetic reassortment. RVFV has caused epizootics in domestic animal populations in African countries, and has been found to affect man, causing acute febrile disease and occasional death due to hemorrhagic fever and encephalitis. Investigators have noted hemostatic changes in primates experimentally infected with RVFV, suggesting that a correlation of hemostatic dysfunction to the human system is possible. This potential for comparative analysis of RVFV-infection in man creates a need for a cost-efficient, readily available model system to study the virus-induced abnormalities in the hemostatic system of man. Wistar-Furth rats prove to be extremely susceptible (LD₅₀, 5 PFU) to infection after subcutaneous inoculation of the Egyptian strain ZH501 of RVFV, and die with extensive liver necrosis 3-5 days post-inoculation. Lewis rats are in contrast largely resistant (LD₅₀, >10⁶ PFU) to the lethal effects of RVFV infection. In utilizing these available rat strains, we examined the general factor deficiencies of the intrinsic and extrinsic pathways of hemostasis which may be acquired secondarily to viral infection, such as liver dysfunction, which is characteristic of RVFV infection. This was accomplished by inoculating adult WF and LEW inbred rats subcutaneously with 5 x 10² plaque forming units of the ZH501 strain of RVFV. Groups of 5 animals were assayed serially at 12 hour intervals. Levels of antibody to RVFV ZH501 in the serum of infected animals were determined by enzyme-linked immunosorbent assay (ELISA). Sera, in addition to liver, spleen, and adrenal gland tissue homogenates were assayed for viral titer, and samples of these tissues were taken for PTAH staining to determine fibrin polymerization. Liver function of the infected animals was assessed by glutamic pyruvic transaminase/alanine aminotransferase (GPT/ALT) colorimetric enzyme assay and compared to values found in uninfected control rats. Complete blood counts (CBCs) and cell differentials were determined in both the virally infected and control animals. Abnormalities of the intrinsic pathway (Factors VIII, IX, XI, XII) were determined by performing a modified activated partial thromboplastin time test (APTT), where as the extrinsic pathway (Factors II, V, VII, X) deficiencies were monitored by a modified prothrombin time test (PT). Variations in clotting times were determined in the infected rats and again compared to the normal values of uninfected control rats. RVFV infection with the Egyptian strain of RVFV, ZH501, was confirmed in both the RVFV-susceptible Wistar-Furth and the RVFV resistant Lewis inbred strains of Rattus norvegicus by virus re-isolation from tissue homogenates of liver, spleen, and adrenal gland, and by the detection of high viremia in the sera of inoculated animals. The acute onset of fatal disease in the susceptible WF strain did not allow sufficient time for detectable IgG production. Hepatic injury was observed by examination of stained tissue sections, and further indicated by the high correlation between viremia, tissue titers, and the prolonged PT and APTT clotting times. Rift Valley Fever virus infection does induce hemostatic change in both the Wistar-Furth and Lewis rat strains to varying degrees, but by which specific mechanisms remains unclear. The results shown here suggest a number of possible mechanisms for hemostatic disruption due to RVFV infection. Severe degrees of hepatic injury lead to impairment of the hemostatic system, not only in its ability to synthesize the coagulation factors, but also in its ability to produce the anti-. coagulation enzymes, which function in the clearance of the activated coagulation factors. These results appeared to be determined by rat genotype. The use of the Wistar-Furth and Lewis rat models is not recommended for the evaluation of Rift Valley Fever virus induced hemostatic change.Item type: Item , FOOD DEPRIVATION, DOMINANCE RANK, AND PARENTAL INVESTMENT IN HOUSE MICE(1989-08) Thornton, Michele W.; Hood College Biology; Biomedical and Environmental ScienceThe Trivers and Willard (1973) theory postulates that female polygynous mammals in good condition should maximize their fitness by investing more in male offspring then in female offspring, while females in poor condition should invest more in female offspring than in male offspring. CF1 mice were used to test this hypothesis. A control group, a premating group (deprived of food every other day one week prior to mating), and a gestation group (deprived of food every third day during gestation) were tested and compared. Both the premating and gestation groups had a higher proportion of female pups than the control group. The premating group had higher fertility than the control or gestation groups. High infant mortality caused the proportions of female pups of the premating group to be closer to the control proportion after the third day. The sons of control, premating, and gestation groups had similar birth weights. However, at adulthood the control males outweighed the premating and gestation males. When dominance ranks were tested among control sons and premating and gestation sons of similar weights, the premating and gestation sons tended to be dominant. When dominance ranks were tested between higher weighing control males and lower weighing premating males, the higher weighing control males were dominant in all cases. Analysis reveals secondary sex ratio results as predicted by the Trivers and Willard (1973) theory as well as some differences in dominance ranks of the male pups which may reflect differences among strains.Item type: Item , REPRODUCTIVE EFFECTS OF 17 13-ESTRADIOL, BISPHENOL A, AND TRIBUTYLTIN IN AIPTASIA PALLIDA(2012-04) Thorn, Heather A.; Hood College Biology; Biomedical and Environmental ScienceThe potential for adverse effects of endocrine-disrupting chemicals and estrogenic pollutants on cnidarians is unknown. Adult sea anemones (Aiptasia pallida) were subjected to three endocrine-active chemicals that are ubiquitous in the marine environment. The 21-day exposure trial included treatments of 17 β-estradiol, bisphenol A (BPA), and tributyltin (TBT) at concentrations found in the coastal marine environment and at concentrations 25X that found in nature. Endpoints monitored included: number of adults producing offspring (lacerates) asexually, number of lacerates produced, and the time for a newly formed lacerate to develop into a juvenile anemone. There was no statistically significant difference in any of these endpoints between treated and control anemones. The data suggest reproductive function of A. pallida is not disrupted by ecologically relevant concentrations of 17 β-estradiol, BPA, and TBT. Future studies should examine the effects of these chemicals on marine invertebrates with more complex reproductive cycles, such as scleractinian corals.Item type: Item , Isolation and Characterization of Rat α₁ and α₂ Macroglobulin and the Development and Purification of their Specific Antibodies(1978-05) Thompson, William L.; Hood College Biology; Biomedical and Environmental ScienceA three step procedure for the isolation of α₁ and α₂ macroglobulin from the serum of turpentine inflamed rats is described. The three steps were; gel filtration on G-150 sephadex, zonal centrifugation using a sucrose gradient, and ion exchange chromatography through DEAE- cellulose. The major improvement in the isolation technique over previous reports was the use of stepwise rather than gradient elution for the separation of α₁ and α₂ macroglobulin on the ion exchange column, which greatly improved the purity and yield of the products. The purified proteins were identified and characterized using acrylamide and SDS gel electrophoresis, thin-layer electrofocusing and immunoelectrophoresis. Differences in the two proteins were noted both in their mobilities and subunit sizes in the electrophoresis gels. A higher pI value than that previously reported was noted for the two α₁ macroglobulin bands formed on electrofocusing plates. This was probably due to improvements in the technique for electrofocusing the macroglobulins. Nitrogen content was determined in order to estimate the actual protein content of the lyophilized material. Amino acid composition of each was determined and compared to levels found by other investigators. Antibody to the purified α₁ and α₂ macroglobulin was developed in goats and purified by ammonium sulfate precipitation and ion exchange chromatography. Titers of antibody in the goat serum were determined by immunodiffusion techniques, and the purity of the isolated antibodies demonstrated by immunoelectrophoresis. Attempts at further purification of the antibodies using affinity chromatography were unsuccessful due to the inability of the α₁ and α₂ macroglobulins which were bound to the support medium to bind their specific antibodies.Item type: Item , COMPARISON OF SINGLE AND DOUBLE UMBILICAL CORD BLOOD TRANPSLANTATION IN PEDIATRIC PATIENTS WITH HIGH RISK LEUKEMIA AND MYELODYSPLASIA(2011-09) Thompson, Jason; Hood College Biology; Biomedical and Environmental Science