Thesis (M.S.)--University of Michigan, 1983.

Thesis (M.S.)--University of North Carolina at Wilmington, 2005. / Includes bibliographical references (leaves: [46]-53)

Thesis (M. S.)--Psychology, Georgia Institute of Technology, 2010. / Committee Chair: Dr. Phillip L. Ackerman; Committee Member: Dr. Paul Corballis; Committee Member: Dr. Ruth Kanfer. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Hyponatremia is common in preterm infants. The causes are usually related to the inability of the premature kidneys to excrete a given water load, excessive sodium losses, or inadequate sodium intake. Here, we present a case of severe hyponatremia in an extreme preterm infant, associated with the use of aminophylline. Aminophylline was administered intravenously on day 1 for the treatment of apnea of prematurity. On day 3, the patient developed hyponatremia which was not responsive to sodium replacement and fluid restriction. Due to concerns of aminophylline‑induced hyponatremia, aminophylline was discontinued on day 6, and within 48 h of discontinuation, serum sodium normalized without the need for sodium supplementation. The purpose of the case report is to present a rare complication associated with aminophylline use and to shed light on potential deleterious effects associated with drug shortages.

It has been demonstrated that EGCG and caffeine, naturally present in green tea, have thermogenic properties in thermoneutral conditions. The purpose of this study was to quantify the effect of the combined ingestion of EGCG/caffeine on thermogenic responses during a 3h mild cold exposure. Eight healthy males (22± 1 y) were exposed in a randomized, cross over, single blinded fashion to the cold (liquid conditioned suit perfused with 15°C water), after ingesting either a placebo (CON) or an extract of 1600mg of EGCG and 600mg of caffeine (EXP). Thermic, metabolic and electromyographic measurements were monitored at baseline and during cold exposure. After 180min of cold exposure, shivering intensity was significantly reduced by ~32% in EXP condition compared to CON. Area under the curve calculations for total shivering intensity was also reduced by ~21% in EXP (457±99 %MVC.min) compared to CON (361±81 %MVC.min; p=0.007). In contrast, the total area under curve of VO2 was ~25% higher in EXP (33.3±5.5 L O2) compared to CON (25.3±5.1 L O2; p=0.03). Total Heat production (Hprod) also increased by about 11% in the EXP condition (1535±112 kJ) compared to control (1372 ±106 kJ; p=0.002). The decrease in shivering activity combined with an increase in VO2 and Hprod, following the ingestion of EGCG and caffeine in the cold, indicates that nonshivering thermogenesis pathways can be significantly stimulated in adult humans.

In this paper, the impact of caffeinated beverages on oral and systemic health was evaluated bringing to light a variety of outcomes. Coffee, tea and energy drinks are beverages that so many individuals around the globe consume in their daily lives yet the potential beneficial or adverse effects are rarely taking into consideration as drinks are consumed. These beverages cause positively influence antimicrobial, anti-cariogenic and anti-inflammatory responses on oral health yet there are also negative consequences that can arise. Society leads individuals to believe that these beverages are a necessity in people’s lives. Therefore, this thesis is written in hope to better understand the effects and impact these beverages have on the human body specifically the oral cavity. Some of these beverages, such as coffee and energy drinks, can have detrimental effects on oral health, teeth and systemic health. Outcomes from excessive intake of these drinks include dental erosion, cavities, and systemic health consequences. These types of beverages should be taken in moderation, otherwise negative effects can arise. On the other hand, sometimes caffeinated beverages can be beneficial to oral health such as when green or black tea are consumed. Considerable research has been performed to better understand the relationship between caffeinated beverages and how they influence the oral cavity. This thesis will evaluate this literature including both the positive and negative effects. With moderate intake, these types of beverages can play a beneficial role in oral and systemic health. In summary, studied have documented the significant beneficial effects of caffeinated beverages including tea, coffee and energy drinks on oral and systemic health. These benefits include antibacterial and anti-cariogenic effects in the oral cavity and improvement in cardiovascular health, metabolism, overcoming fatigue and anti-inflammatory properties with respect to systemic health. As with many things, high or excess intake of caffeinated products can lead to negative consequences such as increased risk of cardiovascular disease, loss of tooth integrity due to sugar and staining leading to tooth discoloration. Research has made great strides in understanding the oral and systemic effects of such beverages. However, there are still unanswered questions that should be pursued in order to truly elucidate the mechanism of action specifically related to the ingredients seen in caffeinated beverages

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Caffeine is one of the most widely used neurostimulants in the world and there is considerable debate on its effect in immune cells. One of its main targets is proposed to be adenosine receptors which mediate an anti-inflammatory switch in activated immune cells while another target is phosphodiesterase where it acts as an inhibitor. In macrophages, caffeine has been shown to cause both pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes. If the primary effect of caffeine on macrophages were to antagonize adenosine receptors we would expect cells exposed to caffeine to have a prolonged M1 response. However, we show that caffeine suppresses phagocytosis at physiological concentrations (an indicator of M2 phenotype). This suppression was reversed when macrophages were pretreated with protein kinase A inhibitor, suggesting that at physiological concentrations caffeine's phagocytic suppression may be due to its function as a phosphodiesterase inhibitor, pushing cells towards an M2 fate. However, mRNA expression profiling suggests that caffeine can modulate A2A receptor expression and suppress MKP-1 expression, a hallmark of M1 macrophages. Caffeine is, therefore an immunomodulator that can suppress or prolong inflammatory responses in macrophages, which may account for the abundance of contradicting evidence in the literature. Additionally, these effects are complicated by regular caffeine intake and fitness level, emphasizing that tolerance and immune robustness are important factors in macrophage activation.

Caffeine, a legal central nervous system stimulant, is commonly consumed by university students in a variety of ways with an implicit belief that it may increase cognitive function. The scientific literature on such benefits has been mixed. In low to moderate doses, caffeine has been shown to reduce fatigue and improve alertness and motor speed while high caffeine consumption is associated with undesirable effects including an inability to focus and increased generalized anxiety. Because the structure of caffeine closely resembles adenosine, it works as an antagonist to increase neuronal excitability. To clarify the effects of caffeine on the brain, this study will examine sensory stimulus-mediated neural synchrony within the prefrontal cortex, a region of the brain associated with executive decision-making as well as in coping with anxiety. When a train of clicks is presented at a particular frequency, neural networks in the brain show oscillatory entrainment at the same frequency. These oscillations represent neighboring neurons firing nearly simultaneously. Such synchronous activation of large networks of neurons is fundamental to the brain’s ability to process and respond to environmental cues and is conveniently measured by the technique of electroencephalography (EEG). EEG as an index of neural network function is well conserved across mammals and used as a translational biomarker to understand the pharmacological effects of drugs within preclinical and human drug development studies. Doses of caffeine mimicking the average range of consumption among college students (100-300 mg/day) are converted into doses suitable for SD rats (10.28 - 30.83 mg/kg) using the FDA’s allometric scaling tool. It is hypothesized that low and medium doses of caffeine may either improve or not affect prefrontal cortical synchrony while high doses may disrupt. The same group of rats will be used for all treatments, including vehicle, in a Latin square crossover design with at least 4 days of gap between dosing. The synchrony response will be evaluated at multiple time points, post-dose. Artifact-free EEG data is averaged to arrive at a synchrony response for each rat and these are further grouped based on treatment and time. Comparisons across treatment and time are done using a 2-factor repeated measures ANOVA, using well-known neural synchrony metrics like evoked power and intertrial phase coherence. These results should inform how caffeine affects the neurophysiological function of the rodent prefrontal cortex, a key region for prioritization, decision-making, and cognitive control. Findings from this study may explain why high doses of caffeine can be disruptive to mental function and performance and lay the groundwork for analogous future studies in humans. On the other hand, if synchrony is unaffected, a chronic regimen of caffeine exposure may be explored to mimic the human consumption pattern of this stimulant.