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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The effect of an a2d calcium channel blocker on sleep parameters in women with chronic primary insomnia: a pragmatic study

Ebrahim, Naseem 03 July 2014 (has links)
Chronic neuropathic pain, epilepsy, depression and anxiety disorders have been treated successfully with pregabalin. Normal subjects, epileptics and patients with neuropathic pain to whom pregabalin was prescribed showed an improvement in objective and subjective sleep parameters. To determine if pregabalin’s sleep enhancing effect is an independent process, it is necessary to test pregabalin in primary insomniacs who do not have conditions that could be treated by pregabalin. My study was designed as a double blind, randomised, crossover, placebo controlled trial, with 50 milligrams of pregabalin or placebo was administered for eight consecutive nights. I performed polysomnographic recordings on eight female chronic primary insomniacs on five nights. Sleep recordings were performed prior to the intervention, and on the first night and eighth night of each treatment. Subjects filled out subjective scales at baseline and night eight of every treatment. While polysomnography and subjective scales showed that my subjects were insomniac, sleep variables during the pregabalin or placebo period were unchanged when compared to baseline. A daily dose of 50 mg pregabalin did not have any significant effects on either sleep architecture or subjective sleep variables in female chronic primary insomniacs.
22

The effect of chronic treatment with propranolol or timolol on the cardiovascular system of the rat

Kendall, Helen Elizabeth January 1985 (has links)
The aim of this project was to study changes in cardiovascular responses brought about by long term oral treatment of Wistar rats with beta adrenoceptor antagonists. After chronic treatment with propranolol (12 or 60 mg/kg/day for up to 6 weeks) or timolol (1.2, 2.5, 5 or 25 mg/kg/day for up to 17 weeks), the log dose-response curves for mean rises in heart rate and mean arterial pressure on stimulation of the postsynaptic adrenoceptors of the pithed rat by I.V. noradrenaline or isoprenaline were not significantly changed. Chronic propranolol treatment significantly reduced the response of the heart to electrical stimulation of the whole sympathetic outflow but treatment with timolol failed to alter the cardiac chronotropic response. The rises in mean arterial pressure on stimulation of the whole sympathetic outflow were not altered by long term treatment with either propranolol or timolol. The high dose of propranolol significantly reduced the heart rate of conscious rats. However neither the lower dose of propranolol nor any dose of timolol affected heart rate. The systolic pressure of conscious rats was unaltered by treatment with the beta adrenoceptor blockers. The threshold for release of tritiated noradrenaline from the sympathetic nerves on stimulation of the whole spinal outflow was raised by chronic treatment with propranolol or timolol. Timolol significantly increased the concentration of 3H noradrenaline in the blood and decreased the heart content of tritium. Chronic propranolol treatment did not alter the blood or heart levels of 3H noradrenaline. Thus, although the plasma levels of the beta adrenoceptor blocking drugs were probably insufficient to ensure prolonged blockade of postsynaptic receptors, significant changes in presynaptic function were observed. It remains to be seen whether these changes play any significant part in cardiovascular responses to beta adrenoceptor antagonists in clinical practice.
23

The effect of a calcium channel blocker on exercise induced muscle damage and hemodynamic parameters in young, healthy adults

Dvorak, Roman 22 July 1996 (has links)
Calcium channel blockers (CCB) was studied extensively in cardiology for their tissue protective effect following myocardial infarction; we hypothesized that administration of a CCB would interfere with the processes that result in exercise-induced muscle damage (EIMD) and delayed onset muscle soreness. To investigate the effects of a CCB on a development and recovery from EIMD, we used a double blind, placebo controlled protocol to administer CARDIZEM CD, 240 mg/day, for 6 days to 30 college age males and females. To induce EIMD, subjects performed 4 sets of 10 repetitions of squat, leg press, leg extension, and leg curl. We observed no treatment related difference in CPK or DOMS levels. Overall, peak quadriceps force (PQF) were not different between the Placebo and Diltiazem groups, but PQF was significantly greater in the Diltiazem groups immediately after the weight lifting bout. Average quadriceps force (AQF) values decreased in both groups following the exercise bout; however, no difference existed between the groups (p>.05). The Diltiazem group PQF and AQF values returned to the pre-exercise levels 24 hours earlier than did the Placebo group. Neutrophils decreased by 21% in the Diltiazem group compare with a 1.4% increase in the Placebo group, due to large variability in the neutrophil count at the baseline, this difference was not significant. Lymphocytes were not affected by CCB treatment. Administration of diltiazem did not interfere with the development of EIMD as measured by CPK release and the DOMS scores. Diltiazem appeared to affect quadriceps force generation immediately following the weight lifting bout and to speed the recovery of muscle force to pre-exercise level in our sample of college age adults. Heart rate was significantly lower in the Diltiazem group after the administration. There was no difference in either systolic or diastolic blood pressure after the administration between the Diltiazem and Placebo groups. The incidence of side effects was very low and similar in both groups. The administration of this dose and preparation of diltiazem does not change heart rate or blood pressure in a clinically significant fashion, and was well tolerated in our sample of college age adults. / Graduation date: 1997
24

The design and synthesis of 5-HT₁B receptor antagonists

Liwicki, Gemma Michele January 2013 (has links)
No description available.
25

Experimental spinal cord injuries : a histopathological, neurological, and pharmacological study in the rat /

Euler, Mia von, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 7 uppsatser.
26

In vitro effects of three organic calcium channel blockers on the rat pineal gland

Brown, Clint January 1992 (has links)
The calcium signal has emerged as an imponant component of intracellular regulation. Pineal function was thought to be slowed by the prominent calcification seen with increasing age, but recently it has been shown that calcium plays a crucial role in the adrenergic regulation of the gland. Beta-adrenoceptor stimulation increases melatonin (aMT) synthesis by increasing the activity of cyclic 3 '-5' adenosine mono phosphate (cAMP). Cyclic-AMP regulates the production of the pineal hormone, melatonin, from serotonin via the rate-limiting enzyme N-acetyltransferase (NAT). Increased intracellular cAMP is essential to the adrenergic induction of NAT. Noradrenaline(NA)also elevates pinealocyte cyclic guanosine monophosphate (cGMP). Adrenergic regulation of these cyclic nucleotides involves both α₁ - and β-adrenoceptors. Beta-adrenoceptor stimulation is an absolute requirement. Alphal-adrenoceptor activation, which is ineffective alone, serves to amplify the β-stimulated cAMP and cGMP responses via a positive effect on a Ca²⁺⁻/ phospholipiddependent protein kinase (Protein kinase-C) and a net influx of Ca²⁺ into the pinealocyte. Previous studies suggest the use of organic calcium channel blockers (CCBs) as probes of calcium-mediated processes. Applying this concept, the study set out to investigate the influence of a representative of each of the structurally diverse groups of calcium channel blockers viz. verapamil, diltiazem and nifedipine, and to examine their effect on β-adrenoceptor stimulation. It used the β-agonist isoprenaline (ISO) and the mixed [α₁/β]agonist noradrenaline (NA), for its combined [α₁/β]adrenoceptor stimulation, on agonist-induced increases in the production of radio-labelled aMT and N-acetylserotonin(aHT) -measured as the sum of N-acetylated product- from [¹⁴C] serotonin. This was done using organ cultures of rat pineal glands. It was speciously assumed that this drug paradigm would allow the determination of Ca²⁺ influx and/or the blocking thereof in the reported potentiation by using ISO as a non Ca²⁺ -entry stimulating agonist, compared with NA and its Ca²⁺ -entry stimulating properties. Surprisingly, all 3 CCB's potentiated the effect of NA. Only diltiazem was found not to potentiate the effect of ISO. In an attempt to uncover the reason for these results, the study moved toward a mechanistic approach,focusing in an antecedent manner on the various steps in the indole metabolic pathway to identify the point at which the change occurred, and hence possibly elucidate the mechanism responsible for the paradoxical increase. Experiments which assayed the levels of NAT, under the same drug conditions, showed the paradoxical increase to be already evident at this stage. Secondary experiments confirmed that NA stimulation of the pineal is dependent on Ca²⁺, both in organ culture and with NAT: the Ca²⁺ chelator EGTA abolished adrenergically-induced stimulation, while Ca²⁺ added after EGTA, restored the enzyme activity. The ionophore A23187 (which is able to transport Ca²⁺ directly into the pinealocyte via a mechanism which differs from the α₁ - mechanism) when used in conjunction with ISO or NA, was able to potentiate the responses of these two agonists relative to control values (agonist-alone), but by itself had no effect. With the enzyme NAT critically dependent upon cAMP for its induction, it was decided to determine the levels of cAMP and then those of its regulator, cAMP-phosphodiesterase (cAMP-PDE). This reasoning was prompted by reports of anti-calmodulin activity shown by the CCBs, in addition to their channel blocking effects. By binding to calmodulin (CaM), the CCBs are reportedly able to inhibit the CaM-dependent activation of cAMP-PDE. Following NA stimulation, verapamil caused a significant decrease in cAMP-PDE levels and an increase in cAMP. The other CCBs showed a similar trend. Glands stimulated with ISO in the presence of verapamil and nifedipine showed no significant differences in cAMP or cAMP-PDE levels. Diltiazem, however, was found to decrease the effect of ISO on cAMP while causing a concomitant increase in cAMP-PDE. This i) supported a possible hypothesis that the observed enhancement is a result of cAMP levels remaining elevated due to an inhibition of cAMP-PDE by the CCEs and ii) pointed to the possible presence of a CaM-sensitive PDE within the rat pineal gland. To test this hypothesis, two drugs which are more specific in their actions on CaM effects were chosen to see if the earlier results could be mimicked and thereby confirmed. Glands stimulated with NA in the presence of the specific CaM inhibitor R 24571 showed increased NAT activity and [¹⁴C]-aMT production. cAMP-PDE levels were clearly down, thus corroborating the possibility of cAMP-PDE inhibition. Glands incubated in the presence of M&B 22948, a CaM-sensitive PDE inhibitor, showed similar increases in NAT activity and [¹⁴C]-aMT. These findings therefore support the initial results and although indirect, confirm the hypothesis that the paradoxical increase following predominantly NA stimulation could be a result of cAMP levels remaining elevated, due to inhibition by the CCEs of the CaM-dependent activation of its regulator cAMP-PDE. In summary, data presented herein concur with proposals that: i) the CCEs are not specific enough to be used as tools to research Ca²⁺ -mediated events, as they appear to have sites of action other than the voltage operated channel (VOC); eg. binding to calmodulin, ii) there are functional differences between the CCEs as shown by diltiazem in this series of experiments, iii) there is a CaM-sensitive-PDE present in the pineal.
27

Synthesis of cycloalkyl analogues of antergan

Wang, Yih Song January 1969 (has links)
Cycloalkyl analogues of Antergan with the basic structure of N, N-dimethyl-N’-cycloalkylmethyl-N’-phenylethylenedi-amlne have been synthesized in good yields. The alkyl group was a butyl-, pentyl-, hexyl-, or heptyl-ring structure. The compounds with the benzyl group of Antergan substituted by a hydrogen or a methyl group were also synthesized in good yields. The general reaction sequence followed was to start with the appropriate cycloalkanecarboxyllc acid and build up to a secondary amine via an acid chloride and an amide. Leung’s methods (1) were followed and checked up to this step. Further reaction sequences were developed during this study. The desired amine was reacted with chloroacetyl chloride, dimethylamine and then reduced to the tertiary diamine analogues. The preliminary antihistamine activity of these analogues was studied and compared with that of Diphenhydramine Hydrochloride Standard Solution. The relative activity of each analogue was also determined. / Pharmaceutical Sciences, Faculty of / Graduate
28

Pharmacokinetics of naltrexone and its conjugated metabolites in dogs and rabbits : a study of biliary excretion and enterohepatic recycling /

Liao, Sam Hui-tseh January 1979 (has links)
No description available.
29

Homeosteric Analogues of Folic Acid, 8-oxadihydropteridines

Dunn, Danny LeRoy 05 1900 (has links)
The introduction of heteroartoms in the pyrazine portion of the pteridine ring has produced compounds which display antifolate activity. The initial objective of this research program was to develop a convenient synthesis of the 8-oxadihydropteridine ring system and to test the resulting compounds for antifolate activity in suitable biological systems.
30

The role of leukotrienes in diseases causing chronic airway obstruction in children

Cook, Arlene Jane January 1996 (has links)
No description available.

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