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Trimethyltin (TMT) is a neurotoxin occurring in the environment. Exposure to (TMT) is known to destroy specific neuronal components of the hippocampus in the rat and to cause clinical symptoms in exposed humans, including mnemonic deficits, that indicate hippocampal involvement. In addition to hippocampal cell loss TMT causes significant increases in cholinergic markers such as acetylcholinesterase (AChE) stain density and choline acetyltransferase (ChAT) activity in the hippocampus of rats. However, despite these observations the effect of TMT on hippocampal cholinergic system has not been investigated in detail. The purpose of the present study was to elucidate more fully the consequences of TMT administration on the rat cholinergic system. To this end the effects of increasing doses of TMT and time after TMT administration on choline acetyltransferase (ChAT) activity as well as TMT's effect on cholinergic muscarinic receptors was examined. Results indicate that 4 and 6 mg/kg doses of TMT measurable neuropathological effects on pyramidal cells of the hippocampus. ChAT activity was increased in the hippocampus as a result of the 6 mg/kg dose. Six mg/kg TMT was observed to affect morphology differentially over time, with the various sub-fields examined being affected at different time intervals. The effect of time on increased ChAT activity after TMT-treatment was observed in the dentate gyrus prior to the CA1 region. The effect of 6 mg/kg TMT on muscarinic receptor distribution over time is first observed in CA1 and CA3c then CA3a-b of the subtype M$\sb2$. The subtype M$\sb1$ receptors are also affected in these regions but at later time intervals. The total distribution of muscarinic receptors is reduced in regions CA1 and CA3c. This is observed at similar time intervals as for M$\sb1$ receptors. The conclusions made as a result of these findings are: (1) That TMT's effect on ChAT activity and morphology of the rat hippocampus is both dose and time dependent; (2) That adverse effects of TMT on ChAT activity and morphology in sub-regions of the hippocampus are observed at different time intervals; and (3) That the distribution of the muscarinic receptors examined are affected by TMT in a regional manner dependent upon the time following administration of TMT.

The purpose of this study was to precisely locate, in living humans, a myofascial trigger point associated with the upper portion of the trapezius muscle (TrP1) that refers pain to the head and neck and to determine if this point is associated with anatomical structures. This study is descriptive and utilizes data from measurements of the location of TrP1 in relation to anatomical landmarks, of pressure sensitivity overlying the trigger point and electromyography recordings in localizing the trigger point. Information obtained from living humans was used to determine anatomical correlation to structures in cadavers. Results indicated there is little variability in the location of TrP1 among individuals or from one extremity to the other, and this point may be associated with structures of the skin. A neurovascular supply (NAV) emerging from the upper trapezius to the skin was located in cadavers resembling the location of TrP1 in living humans. This NAV contained only small diameter nociceptive nerve fibers. Conclusion from the study show that TrP1 in living humans can be precisely located and that the mechanism of pain referral may involve structures of the skin. Future studies to precisely locate other myofascial trigger points may aid in identifying mechanisms of trigger point activation as well as aid clinicians in more precisely locating trigger points for treatment.

Around 1% of the population worldwide suffer from epilepsy, a condition which is characterized by recurring seizures. The development of reliable biomarkers for both prediction and targeted treatment of seizures is critical, as they can pave the way towards personalized therapy in epilepsy. In addition, sensitive biomarkers can be utilized for the detection of epilepsy in its early stages and allow for early treatment intervention. Various types of biomarkers have been studied in relation to epilepsy, with blood markers emerging as major candidates. Blood biomarkers offer the benefit of being cost and time efficient, in addition to being less invasive to sample in contrast to cerebrospinal fluid markers. Importantly, they can enhance patient diagnosis and prognosis when supplemented with other diagnostic methods, such as EEG. In this pilot study, five blood biomarkers of brain injury are studied in epilepsy, post-stroke epilepsy and single seizure patients. The aim is to analyze whether S100B, NSE, GFAP, NfL and tau are promising indicators of epilepsy after a first seizure in adults. The results present S100B as the most promising biomarker, with potential to predict early epilepsy.

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published_or_final_version / Psychology / Doctoral / Doctor of Philosophy

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No description available.