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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PLACENTAL MONOCYTE FUNCTION
(1996-05) Brown, Irene A.; Hood College Biology; Biomedical and Environmental Science
Modern technological advances have allowed investigators to learn a great deal about
the feto-maternal interface. However, much is still not understood about the immunological
basis of a successful pregnancy. Even though a few fetal erythrocytes and leukocytes escape
into maternal circulation and minor breaks in the placental barrier allow cells to escape in both
directions, cells of the embryo normally do not come into direct contact with maternal blood.
Maternal blood flows into the placenta filling the intervillous spaces and circulates around the
fetal villous tree. The focus of this study was to investigate maternal monocyte function at the
time of labor and delivery, particularly the ability to activate monocytes to phagocytize
bacteria. Maternal peripheral blood was collected during labor and again within 24 hours of
delivery. Placentas were harvested and maternal blood from the intervillous spaces was
collected within 6 hours of delivery. Monocytes were separated from all whole blood test
specimens as well as nonpregnant female control subjects by density gradient centrifugation
and adhesion of monocytes to plastic. The monocytes were then incubated in culture medium
with an equal ratio of Listeria monocytogenes bacilli. Monocytes were treated with
recombinant human gamma-interferon as an activation signal. No significant difference in the
number of viable phagocytized bacteria between interferon-treated and untreated monocytes
was observed in any of the test specimens. There was a small, yet statistically relevant,
increase in the interferon-treated control cells after 20 hours incubation. The inability of
interferon alone to activate monocytes from the placenta and peripheral circulation of women
during delivery may be due to the need of a second cooperative signal, perhaps TNF-a or
GM-CSF. An alternative is that due to the nature of the processes of labor and delivery, there
were present both locally in the placenta and globally in the general circulation various
mediators that have the ability to initiate labor and modulate monocyte activity. Further study
is warranted to test the ability to activate these monocytes. The production of reactive nitrogen
and oxygen intermediates could be assayed as well as the effect of various uterotonins on the
activation process. If the immunological processes preventing the rejection of a genetically
dissimilar fetus were understood, progress could be made in transplantation science as well as
the treatment of infertility and novel approaches to birth control.
FELINE IMMUNODEFICIENCY VIRUS IN EXOTIC FELIDS: A SEROEPIDEMIOLOGIC AND PHYLOGENETIC CHARACTERIZATION
(1993-10) Brown, Eric Wayne; Hood College Biology; Biomedical and Environmental Science
Feline immunodeficiency virus is a recently isolated T-lymphotropic
lentivirus that is genetically homologous and functionally analagous to
the human AIDS viruses, HIV-1 and HIV-2. FIV has been documented to cause
immunosuppression by gradually destroying the CD4 bearing T-cell subsets
in infected domestic cats. Recent studies have revealed the existence of
cross-reactive antibodies to FIV in several species of nondomestic felids.
This thesis reports on the results of a seroepidemiologic survey of nearly
2000 serum samples from 20 different feline species and a molecular
characterization of the pol gene from African lion FIV isolates. Evidence
of exposure to feline lentiviruses was found in ten species of felids
including lions, pumas, cheetahs, and bobcats. FIV exposure rates were
found to be endemic in several populations of East African lions with an
incidence as high as 90% in some areas. This report also documents the
natural seroconversion of two East African lions. The phylogenetic
reconstruction of the conserved viral poi gene has revealed huge intra-
and inter- individual genetic diversity at the sequence level. The
analysis has shown that feline lentiviruses appear to assort
monophyletically with respect to the host species suggesting that
interspecies transfer is a rare event. Three major phylogenetic clades of
lion lentivirus (LLV) have been described that may be ancestral in their
origins. The physiological consequences of FIV infection in big cats
remains unclear, but the results of these studies show large parallels to
the natural history of SIV infection in African primates, notably of the
genus, Cercopithecus.
Detection of IgG-Associated Determinants in Reduced and Alkylated Preparations of Human IgG3 by Monoclonal Antibodies
(1985-05) Brown, Adrienne M.; Hood College Biology; Biomedical and Environmental Science
Using classical typing antisera, previous experiments have failed
to demonstrate IgG3 in partially reduced and alkylated preparations of
human IgG intended for intravenous application (IGIV). To establish
that IgG3 is actually present in such preparations and to investigate
the effects of reduction and alkylation on IgG3-associated epitopes, an
enzyme-linked immunosorbent assay (ELISA) was designed using monoclonal
antibodies as solid phase reagents and protein A-purified IgG3 as
antigen. Three different samples of reduced and alkylated antigen were
used: 1) IgG3 isolated from a ready-for-infusion IGIV; 2) IgG3 which
was purified from an intramuscular (Cohn Fraction II) IgG solution
before being subjected to a mild reduction and alkylation procedure;
and 3) completely reduced and alkylated IgG3. The reduction and
alkylation procedure did not affect the solubility of IgG3, indicating
that IGIV prepared in this manner should contain normal quantities of
IgG3. In the ELISA, solid-phase monoclonals which were cross-reactive
with multiple IgG subclasses clearly reacted with reduced and alkylated
IgG3. Furthermore, there was no substantial difference between the
quantities of modified and native antigen required for 50% maximal
ELISA signal. In contrast, solid-phase monoclonals with
IgG3-restricted specificity did not recognize reduced and alkylated
material. These results indicate that IGIV prepared by reduction and
alkylation has a normal IgG3 content and confirm that some
IgG3-specific determinants are altered by the modification procedure.
Histopathologic Response in the Fathead Minnow (Pimephales promelas) Exposed to 2,4-Dinitrotoluene in an Early Life Stage Toxicity Test.
(1982) Broich, Stephen G.; Hood College Biology; Biomedical and Environmental Science
The histopathologic examination of fathead minnows (Pimephales promelas)
exposed to 2,4-dinitrotoluene (2,4-DNT) in an early life stage (ELS) toxicity
test was compared with a chronic life cycle test performed by Liu and
Bailey (1981) at SRI International (SRI). Pathologic conditions associated
with 2,4-DNT exposure were found in the gill, liver, spleen and trunk kidney .
in all concentrations tested (ranging from 0.27 - 3.58 mg/L). Edematous
"ballooning" and fused "blanketing" of secondary lamellae characterized gill
damage. Lipid accumulation and limited focal fatty necrosis were observed
in the liver. Abnormal accumulations of hemosiderin in the spleen and
atypical renal tubules and corpuscles in the trunk kidney were evident.
A weighting scheme was applied based on biological significance of the lesions
observed to determine a no-effect level. No threshold level was attained
below which histologic effects would be expected to be absent. The SRI
chronic maximum allowable toxicant concentration (MATC) was less than 0.44
mg/L 2,4-DNT. In the ELS test, the MATC was less than 0.27 mg/L 2,4-DNT.
Thirty day survival effects in the ELS test compared favorably. Thirty day
SRI F0 growth effects were found at concentrations of 1.75 mg/L and above.
No growth effects were observed in the ELS test at concentrations up to
3.58 mg/L. Based on these comparisons, the usefulness and sensitivity of
ELS toxicity testing is increased with the addition of histopathologic
evaluation, thereby helping to formulate more appropriate water quality
criteria.
Biochemical Characterization of Plasma Membrane-Associated Interleukin 1
(1987-05) Brody, Dan T.; Hood College Biology; Biomedical and Environmental Science
Until now, murine plasma membrane-associated IL-1 has only been
described as a poorly understood IL-1 biological activity.
Evidence is presented herein that plasma membrane IL-1 is
actually glycosylated IL-1 precursor bound to the plasma membrane
through a lectin-like association with a carrier molecule.