Delayed hypersensitivity can be conferred passively to normal animals. There exists a period when whole peritoneal exudate cells will passively confer delayed sensitivity, but a sonic extract from them will not; however, after a few more days, both whole cells and sonic extracts could transfer sensitivity. This investigation was undertaken to study the differences in cells collected at two different time intervals after initial sensitization of guinea pigs with 1-fluoro-2,4-dinitrobenzene.

The purpose of this study is to determine the presence or absence of a typical Krebs cycle metabolism in the primary mycelia of an aquatic streptomycete.

The present studies determine the accumulation of persistent organic pollutants (POPs) in three pinniped species, evaluate the relationship with relevant biomarkers of exposure, and calculate toxic effect thresholds. Stranded harp and hooded seals were found to be accumulating PBDEs at levels which could pose a based on threshold levels determined in this study. Northern fur seals are accumulating all three classes of POPs (PCBs, PBDEs, and OCPs) with significant relationships being seen with blubber percent lipid. Correlations between contaminant concentrations and expression levels of relevant biomarkers were seen potentially indicating an effect on multiple pathways. Overall risk can be hard to determine due to factors such as sex and age. Broad threshold response values and hazard quotients were calculated for toxic effect endpoints in pinnipeds. Overall these results suggest that certain populations of pinnipeds are at high risk of experiencing toxic effects due to POP exposure, but it is important to understand effects even at lower concentrations. The relationship between exposure, toxic effects, and other stressors, both environmental and physiological, can impact the overall fitness and survival of pinnipeds.

The major purpose of this investigation was to determine the effect of carbon monoxide on the development of various morphological phases of a single isolate of the aquatic streptomycetes and to elucidate the physiological differences between terminal respiration in the primary and secondary stages. A secondary purpose was to repeat the work of Michael Lee Higgins involving the effect of anaerobiosis on the growth of the organism.

A study of hypersensitivity of high school students to the oleoresins of fifty common North Texas plants.

Having considered the data collected thus far concerning immediate and delayed hypersensitivity reactions in the mouse, the experimentation following is devised essentially to follow the pattern of Crowle in the production and testing for immunoresponse. Instead of using the normal solvent, that is, acetone, this work is also intended to partially evaluated the use of dimethyl sulfoxide as a solvent for the contact allergin, dinitroflurobenzene.

The induction of phenylketonuria in mice through the use of excess dietary phenylalanine is an area in which limited research has been done. This study intends to pursue further work in this area, more specifically, to study the effects of excess dietary phenylalanine and the phenylalanine analogue A.P.B.A. (2-amino-3-phenyl butanoic acid) (7) on brain serotonin and brain norepinephrine. In addition, the effects of these two compounds on the incidence of audiogenic seizures will be explored.

This study employed a new model of mild-to-moderate head trauma to specifically identify the role of dural mast cell (MC) histamine in trauma-induced increased permeability in the blood-brain barrier (BBB). A single line was scored partially through the left dorsal parietal skull. Immediately following the trauma, degranulation was seen in 39% of the MCs on the left and in 2% on the right. After a 20 min survival period, left duras showed 55% with MC degranulation (fewer with complete degranulation) compared to 34% on the right. In the other experiments two parallel lines were scored following the injection of Evan's blue. Histamine assay showed histamine increased in the left cortex to 154% at 5 min, 174% at 10 min, and 151% at 20 min. Fluorescent quantitation of extravasated Evan's blue at 20 min following the trauma gave an increase of 1385% over the value measured for the right cortex. Zolantidine, a selective histamine H2 receptor antagonist, administered at 10- and 20- mg/kg 30 min before the trauma blocked 65% of the Evan's blue extravasation compared with the control and 2.5 mg group.

The purpose of the current study is to determine something of the nature of the heat resistance in Azotobacter, if in fact this is found to exist. An attempt is made to determine the specific physiological state associated with heat resistance as well as to resolve this resistance quantitatively.

Evaluation of museum audiences both in their physical and web-based spaces is a necessary component of museum education. For smaller museums without the personnel or knowledge to create a website and evaluate the on-line audience, using a web-based learning tool may be able to help these museums properly maintain an online site. A web-based Elm Fork Natural Heritage Museum (WBEFNHM) was created during the 2008 fall semester at the University of North Texas. The site included photographs and information from specimens housed within the physical Elm Fork Natural Heritage Museum. The site was available to three non-science majors' biology laboratory courses, and three science majors' biology laboratory courses during the 2009 spring and fall semesters. Student use of the WBEFNHM was tracked and found no significant difference between the amount of time science majors and non-majors spent on the site. This evaluation helps in understanding future use of an online EFNHM.

The purpose of this study is to determine if a strain of Azotobacter chroococcum isolated from the soil in northern Louisiana produces cysts which are as resistant to deleterious agents as those produced by previously reported strains os Azotobacter.

Bacillus subtilis (ATCC 19659) were damaged by exposure to various concentrations of glutaraldehyde, as shown by decreased germination rates. The damage caused was repaired or otherwise obviated by the presence of sodium lactate in the holding medium. When two different salts of lactic acid were compared for ability to overcome the effect of glutaraldehyde, it was found that calcium salt of lactate was more effective than the sodium salt. The damage repair system involved l-alanine, lactate and either the sodium or calcium ions. The study involved in determining the difference in efficiency of spore repair was due to an organic or an amino acii snowed that the presence of two carboxylic functional groups did not effectively alter the reactivity.

The goals of this dissertation work were to assess the bioaccumulation potential of carbamazepine and amiodarone, two widely used ionizable pharmaceutical compounds that possess mid-range and high LogD values, respectively, and to evaluate alternative methods to assess chemical accumulation in bluntnose minnows, catfish, and tilapia. Results indicated that carbamazepine does not appreciably bioaccumulate in fish tissue with BCFk and BAF carbamazepine values < 10. Amiodarone, however, with a log D of 5.87 at pH 7.4, accumulated in fish tissues with kinetic BCF values <2,400. Collectively, the data suggest that full and abbreviated laboratory-derived BCFs, BCFMs derived from S9 loss-of-parent assays, as well as field BAF values are similar for each of the two drugs. In summary, the results from this dissertation indicated: 1) The reduced design BCF test is a good estimate for the traditional OECD 305 test. 2) In vitro S9 metabolism assays provide comparable BCF estimates to the OECD 305 test. 3) Metabolism may play a large role in the accumulation of drugs in fish. 4) Reduced BCF tests and in vitro assays are cost effective and can reduce vertebrate testing.

Exactly where in the hypothalamus is the adrenal-pituitary response to X-irradiation "triggered" or initiated? Moreover, does ionizing radiation act directly on specific centers in the brain or does it act indirectly via the production of some humoral agents? Finally, what role does the hypothalamus play in the radiation-syndrome? The purpose of the present study was to attempt to answer these questions by determining the effects of two stressor agents, X-irradiation and electrical stimulation applied either singly or together, on the activity of the adrenal-pituitary axis. The parameters measured were changes in plasma corticosterone, in circulating eosinopihils, and in adrenal gland weight.

The present study may be considered endocrinological and radiobiological in nature. The endocrinology phase was concerned with studying the changes in endocrine function following the application of a stress agent. X-irradiation was chosen as the stressor in order to determine any difference in effect of this stressor from others which have been studied, e. g. heat, cold, metabolic poisons. Liver slices taken from rats at various time intervals following whole body X-irradiation were tested for their ability to metabolize hydrocortisone from a Krebs-Ringer solution.

This investigation deals with the study of a possible hypersensitivity to the oleoresins of fifty common plants indigenous to Hunt County, Texas.

The aim of this study is to determine the changes in respiration in tissues from specific brain areas X-irradiated in vitro using a direct monometric procedure also to determine the differences in radiosensitivity of specific areas in the brain as reflected by changes in oxygen uptake and to shed some light on the nature of the biochemical lesions in nerve tissues brought about by ionizing radiation.

The purpose of this study was twofold: 1) to present experimental data on changes in permeability of fibers during irradiation using Na22 as the tracer isotope, and 2) to attempt to correlate these findings with the electrical changes observed.

Polycyclic aromatic hydrocarbons (PAHs) are a well studied and diverse class of environmental toxicants. PAHs act via the aryl hydrocarbon receptor (AhR), and studies have suggested that PAHs may elicit neurological and estrogenic effects. Doses of PAHs between 50 to 150 ppm may elicit neurotoxicity in rodent models. The present study investigated the effects of naphthalene on in vivo steroidogenesis in Swiss Webster male mice, and in vitro neural function of Balb-C/ICR mice frontal cortex neurons. These data suggest that naphthalene may not elicit steroidogenic effects at concentrations ranging from 0.2 to 25 mg/kg/day, following a 7 day subcutaneous dosing regime. In addition, naphthalene may cause functional toxicity of frontal cortex neurons at concentrations of 32 to 160 ppm naphthalene.

In this study organisms that can be subcultured from lake water, using a prescribed procedure, limit, to an extent, the population, or portions of the population, that can be monitored. In essence, what is taking place is that a set of conditions is set forth and a study is made of the bacteria that will grow under these prescribed conditions.

Spontaneously active frontal cortex and spinal cord networks grown on microelectrode arrays were used to study effects of D-methylphenidate. These central nervous system tissues have relatively low concentrations of dopaminergic and noradrenergic neurons compared to the richly populated loci, yet exhibit similar neurophysiological responses to methylphenidate. The spontaneous spike activity of both tissues was inhibited in a concentration-dependent manner by serial additions of 1-500 µM methylphenidate. Methylphenidate is non-toxic as spike inhibition was recovered following washes. The average concentrations for 50% spike rate inhibition (IC50 ± SD) were 118 ± 52 (n= 6) and 57 ± 43 (n = 11) for frontal cortex and spinal cord networks, respectively. A 3 hour exposure of a network to 1 mM methylphenidate was nontoxic. The effective concentrations described in this study are within the therapeutic dosage range. Therefore, the platform may be used for further investigations of drug mechanisms.

A recent chemical spill of 4-Methylcyclohexanemethanol (4-MCHM) in West Virginia left 300,000 people without water. Officials claimed that this compound is not lethally toxic, but potentially harmful if swallowed or inhaled, and can cause eye and skin irritation. Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens reports high exposures from skin contact or inhalation may cause damage to the heart, liver, kidneys, and lungs, and may result in death. However, no quantitative data seem to exist and no references can be found on neurotoxicity. We have investigated the neurotoxicity of 4-MCHM using mammalian nerve cell networks grown on microelectrode arrays. Network spontaneous activity from multiple units (range 48 – 120 per network) were used as the primary readout. Individual units were followed based on spike waveforms digitized at 40 kHz (Plexon MNAP system). Dose response curves show the effective inhibitory concentration at 50 percent decrease (EC50) to average 27.4 microM SD±6.17. However, in the presence of 40 microM bicuculline, a competitive GABAA antagonist, the EC50 shifts to 70.63uM SD ±4.3; implying that early, low concentration exposures to 4-MCHM involve GABA activation. Initial activity loss occurs without active unit loss (defined as 10 or more template threshold crossing per min), indicating …

Mercury (Hg) is a ubiquitous environmental contaminant, which is capable of global atmospheric transport. As a result, even the most pristine aquatic ecosystems are affected by atmospheric Hg deposition, following which microbial transformation yield organic Hg forms, the most concerning of which is methylmercury (MeHg). Methylmercury is capable of bioaccumulation and biomagnification in food webs, resulting in potentially toxic body burdens due to regular dietary exposure in long-lived organisms at higher trophic levels. It is also a molecular mimic of some endogenous amino acids, providing a route of transfer from mother to offspring via large amino acid transporters. Exposure during neurodevelopment can lead to serious, irreversible neurological dysfunction, associated with a variety of cognitive and motor abnormalities across species. The present studies evaluate the effects of maternally-transferred dietary MeHg, at environmentally relevant concentrations on early life stage fathead minnows (Pimephales promelas). Embryos were collected from adult fatheads exposed to one of three diets with varying concentrations of MeHg for 30 days. Adult reproductive metrics were also monitored over the course of the study, with results indicating no effects on spawning frequency, clutch size, or total egg output. In embryos, Hg concentration was a function of female diet and the duration …

The Cardiac Profile, a pattern of serum enzyme changes seen within seventy-two hours after an AMI, is diagnostic aid for detecting occurrence of infarcts. The effects of exercise stress on the Cardiac Profile aid clinicians in avoiding diagnostic errors in patients immediately after exercise. Five male volunteers ran from six to ten miles. Serum enzyme levels were monitored serially three days before and five days after stress. Enzyme activity was determined spectrophotometrically and electrophoretically. Significant increases in total CPK and LDH were seen. An LDH 'one-two flip' occurred eight hours after exercise. No MB-CPK was found following the run.