1. Zusammenfassung Während der Embryogenese und nach Verletzungen von Nerven regulieren neurotrophe Faktoren Signalwege für Apoptose, Differenzierung, Wachstum und Regeneration von Neuronen. In vivo Experimente an neugeborenen Nagern haben gezeigt, dass der Verlust von Motoneuronen nach peripherer Nervenläsion durch die Behandlung mit GDNF, BDNF, und CNTF reduziert werden kann In der pmn-Mausmutante, einem Modell für die Amyotrophe Lateralsklerose, führt die Gabe von CNTF, nicht aber von GDNF zu einem verzögerten Krankheitsbeginn und einem verlangsamten Fortschreiten der Motoneuronendegeneration. Auslöser der Motoneuronendegeneration in der pmn-Maus ist eine Mutation im Tubulin spezifischen Chaperon E (Tbce) Gen, das für eines von fünf Tubulin spezifischen Chaperonen (TBCA-TBCE) kodiert und an der Bildung von -Tubulinheterodimeren beteiligt ist. Diese Arbeit sollte dazu beitragen, die CNTF-induzierten Signalwege zu entschlüsseln, die sich lindernd auf den progredienten Verlauf der Motoneuronendegeneration in der pmn-Maus auswirken. Primäre pmn mutierte Motoneurone zeigen ein reduziertes Axonwachstum und eine erhöhte Anzahl axonaler Schwellungen mit einer anomalen Häufung von Mitochondrien - ein frühes Erkennungsmerkmal bei ALS-Patienten. Die Applikation von CNTF nicht aber von BDNF oder GDNF, kann in vitro die beobachteten Wachstumsdefekte und das bidirektionale axonale Transportdefizit in pmn mutierten Motoneurone verhindern. Aus älteren Untersuchungen war bekannt, dass CNTF über den dreiteiligen transmembranen Rezeptorkomplex, bestehend aus CNTFR, LIFR und gp130, Januskinasen aktiviert, die STAT3 an Tyrosin 705 phosphorylieren (pSTAT3Y705). Ich konnte beobachten, dass axonales fluoreszenzmarkiertes pSTAT3Y705 nach CNTF-Gabe nicht retrograd in den Nukleus transportiert wird. Stattdessen führt die CNTF-induzierte Phosphorylierung von STAT3 an Tyrosin 705 zu einer transkriptionsunabhängigen lokalen Reaktion im Axon. Diese pSTAT3Y705 abhängige Reaktion ist notwendig und ausreichend, um das reduzierte Axonwachstum pmn mutierter Motoneurone zu beheben. Wie die Kombination einer CNTF Behandlung mit dem shRNA vermittelten knock-down von Stathmin in pmn mutierten Motoneuronen zeigt, zielt die CNTF-STAT3 Signalkaskade auf die Stabilisierung axonaler Mikrotubuli ab und wirkt sich positiv auf die anterograde und retrograde Mobilität von axonalen Mitochondrien aus. Interessanter Weise konnte ich außerdem feststellen, dass eine akute Gabe von CNTF das mitochondriale Membranpotential in Axonen primärer pmn mutierter und wildtypischer Motoneurone erhöht und einen Anstieg von ATP auslöst. Meine Beobachtungen legen nahe, dass CNTF unerwarteter Weise auch eine transiente Phosphorylierung an STAT3 Serin 727 (pSTAT3S727) auslöst, die zur anschließenden Translokation von pSTAT3S727 in Mitochondrien führt. Diese Ergebnisse zeigen, dass STAT3 mehrere lokale Ziele im Axon besitzt, nämlich axonale Mikrotubuli und Mitochondrien. / 2. Summary Both during development and after injury neurotrophic factors induce signaling pathways that regulate apoptosis, differentiation, growth and regeneration of neurons. In newborn rodents, treatment with GDNF, BDNF and CNTF can reduce the loss of motoneurons after peripheral nerve lesion. In the pmn mutant mouse, a model for amyotrophic lateral sclerosis, CNTF but not GDNF delays disease onset and slows down the course of motoneurons degeneration. Pmn mutant mice, suffer from a point mutation in tubulin specific chaperon E (Tbce) gene that codes for one of five tubulin specific chaperones (TBCA-TBCE) and is necessary for proper -tubulin heterodimer formation. The work presented here was designed to study the specific signaling pathways that are used by CNTF for attenuating progression of motoneuron degeneration in pmn mutant mice. Primary motoneurons from pmn mutant mice show reduced axon growth and irregular axonal swellings with abnormal accumulation of mitochondria – an early hallmark of pathology in ALS patients. In vitro, CNTF but not BDNF or GDNF was able to rescue defective axon growth and to prevent bidirectional transport interruption. It has already been shown that CNTF acts via the tripartite transmembrane receptor complex, composed of CNTFR, LIFR and gp130 to recruit Janus kinases that subsequently phosphorylate STAT3 on tyrosine 705 (pSTAT3Y705). After application of CNTF, I observed that axonal pSTAT3Y705 fused to a fluorescent tag is not retrogradely transported to the nucleus. In contrast, CNTF induced phosphorylation of STAT3 at tyrosine 705 leads to a transcriptional independent local reaction in motor axons which is necessary and sufficient to rescue axon growth in pmn mutant motoneurons. Combining CNTF treatment with shRNA mediated knock-down of Stathmin in pmn mutant motoneurons shows that CNTF-STAT3 signaling leads to microtubule stabilization in axons as well as improving anterograde and retrograde mobility of axonal mitochondria. Interestingly, I additionally found that an acute application of CNTF increases the membrane potential of axonal mitochondria that is accompanied with a rise of ATP levels in pmn mutant and wildtype motoneurons. Unexpectedly, I found STAT3 phosphorylated on serine 727 co-localizing with mitochondria after CNTF application. These results demonstrate that multiple local targets of STAT3 exist in axons that modulate structure and function of microtubules and mitochondria.

Typewritten copy Includes bibliographical references (leaves 141-144) Pt. 1. Historical review -- pt. 2. Techniques used in electron microscopy -- pt. 3. Experiments on cilia from Hydrdella australis -- pt. 4. Electron microscope experiments on cilia from the rat trachea -- pt. 5. Electron microscope experiments on cilia from paramecium -- pt. 6. Electron microscope experiments on the trichocysts of paramecium -- pt. 7. Discussion An account of experimental investigations carried out from January 1952 to September 1954.

Abstract The combinations of four temperatures (20, 25, 30, 35¢J) and six salinities (5, 10, 15, 20 ,25, 30psu ) were employed to study the effects of environmental factors on the speed of ciliary movement of the gill and the oxygen consumption of hard clam Meretrix lusoria and purple clam Sanguinolaria rostrata. The results show that, at the same salinities, the speed of ciliary movement of the gill and the oxygen consumption of M. lusoria increased with increasing temperature and reached the maximum at 30¢J, but declined at 35¢J. In contrast , the speed of ciliary movement of the gill and the oxygen consumption of S. rostrata increased with increasing temperature, and the maximum was at 35¢J. S. rostrata can adapt to higher temperature than M. lusoria does. At the same temperature, the speed of ciliary movement of the gill and the oxygen consumption of two bivalves increased with increasing salinity, reaching its maximum at 15~25psu, and declining at higher salinity ranges. These two bivalves like to live in estuaries. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of M. lusoria occurred at 30¢J, 20 psu (1.23 cm/min and 1.78 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 2.5 and 2.8, respectively. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of S. rostrata were at 35¢J, 25 psu (1.64 cm/min and 1.45 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 4.0 and 5.8, respectively. Temperature and salinity had more remarkable effects on S. rostrata than on M. lusoria. In another experiment, the combinations of four temperatures (20 ,25 ,30 ,35¢J) and three salinities (10, 20, 30 psu) were employed to study the effects on the speed of ciliary movement of the gill and the oxygen consumption of small M. lusoria and small S. rostrata. The results show that the effects of all temperature-salinity combination on the speed of ciliary movement of the gill and the oxygen consumption of the small bivalves were similar to that of the large ones. The physiological conditions of the small bivalves were similar to that of the large ones. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of small M. lusoria were at 30¢J, 20 psu (1.31 cm/min and 5.56 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 2.5 and 3.0, respectively. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of small S. rostrata were at 35¢J, 20 psu (1.67 cm/min and 3.96 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 2.9 and 7.1, respectively. Temperature and salinity had more remarkable effects on small S. rostrata than small M. lusoria. Our results also show that the oxygen consumption is positively correlated with the speed of ciliary movement of the gill in both bivalves (R2¡á0.94). The speed of ciliary movement of the gill can be regarded as an physiological indicator. The speed of ciliary movement of the gill of M. lusoria changed very significantly when the temperature was suddenly changed 5¢J or when the salinity was suddenly changed 10psu. The condition then stabilized only gradually. The speed of ciliary movement of the gill showed no pronounced variations after 50~70 minutes. We found that when the temperature or salinity was changed suddenly, the physiological condition of M. lusoria was disturbed and became stable after 70 minutes. M. lusoria died at 5psu (35¢J), but S. rostrata didn¡¦t. S. rostrata can adapt to higher temperature and lower salinity. The cultivation of S. rostrata is easier than M. lusoria. The effects of temperature changes were more significant than those of salinity. Temperature variations were more important than salinity variations on cultivation of M. lusoria and S. rostrata.

We design actuated cilia that can maneuver microscopic particles normal to a microfluidic channel wall and transport microscopic particles parallel to the channel wall. For identifying the design specifications, we employ a hybrid LBM/LSM computational model, to simulate hydrodynamic interactions between oscillating elastic cilia and microscopic particles in a microfluidic channel. The oscillating synthetic cilia are elastic filaments tethered to the channel wall and actuated by sinusoidal force acting at their free ends. The cilia are arranged in a square pattern. The microscopic particle is a neutrally buoyant solid sphere, which is sufficiently small compared to the cilium length and inter-cilium distances, so that the particle can move freely inside the ciliated layer. We study the effect of actuation frequency on the particle motion inside the ciliated layer. We show that depending on the frequency, particles can be either driven away from the ciliated channel wall or drawn towards the wall. We also examine how to use inclined cilia to transport particles along the ciliated layer. We show that the particle transport along the ciliated layer can be regulated by the frequency of cilium oscillation. The results uncover a new route for regulating particle position and transport in microfluidic devices.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 111-122).

The vertebrate planar cell polarity (PCP) pathway has been previously found to control polarized cell behaviors rather than cell fate. We report here that disruption of Xenopus laevis orthologs of the Drosophila melanogaster PCP genes Xint or Xfy affected not only PCP-dependent convergent extension but also caused embryonic phenotypes consistent with defective Hedgehog signaling. These defects in Hedgehog signaling resulted from a broad requirement for Inturned and Fuzzy in ciliogenesis. We show that these proteins are necessary for the formation of both primary cilium in the neural tube and multi-cilia in the epidermis. Also, using Xenopus muco-ciliary epidermis, we demonstrated that one of the core PCP genes Dishevelled performs dual functions in ciliogenesis, basal body docking and planar polarization of ciliary beating. To this end, we showed that Dishevelled works in concert with the PCP effector protein Inturned and Rho GTPase to mediate the docking of basal bodies to the apical cell surface. We suggest that this docking involves a Dvl-dependent association of basal bodies with vesicles, and with the vesicle-trafficking protein Sec8. Finally, we showed that independent of their roles in apical docking, Dvl/PCP signaling is required again for directional ciliary beating. For the first time, this study uncovered the mechanism for controlling the apical docking of basal bodies. Moreover, the results suggest that the same Dvl/PCP signaling is also important for the planar polarization of ciliary beating in a vertebrate muco-ciliary epithelium. / text

published_or_final_version / Medicine / Master / Master of Research in Medicine

A comprehensive review of the nasal route of administration, in particular the nasal drug delivery system has been presented. The physicochemical properties, mode of action and pharmacology of H1-receptor antagonists, in particular cyclizine HCl, have been highlighted. The techniques for the assessment of toxicity (in-vitro ciliary beat frequency (CBF) studies for human nasal explants and morphology studies of the rat nasal mucosa), synthesis of cyclizine lactate, solubility studies of both cyclizine HCI and cyclizine lactate, viscosity determination of the gel formulated and assessment of the deposition and distribution of the hydroxypropylmethyl cellulose (HPMC) dispersions within the human nasal cavity model were conducted. In this study, preliminary studies on the toxicity of the various formulation components (excipients and active ingredient) were carried out. Results from these studies indicated that for both the excipients and the drug, pH significantly affects the ciliary motility hence all ciliary beat frequency determinations were conducted at nasal pH. Furthermore, effects of the various concentrations (0.0625%(w/v), 0.125%(w/v), 0.25%(w/v), 0.5%(w/v) and l%(w/v)) of the excipients on ciliary motility were investigated. Transmission electron microscopy (TEM) studies proved useful in evaluating the integrity and changes in the surface morphology of the rat nasal mucosa post treatment with the various excipients (carboxymethyl cellulose, hydroxypropylmethyl cellulose, trimethyl chitosan 36.3% DQ, Carbopol P934 and polysorbate-80) at varying concentrations. Of the excipients investigated, hydroxypropylmethyl cellulose (HPMC) showed ciliofriendliness since there was no apparent ultra structural damage, although a slight decrease in ciliary beat frequency (CBF) was observed at the highest viscosity. Moreover, hydroxypropylmethyl cellulose (HPMC) is said to be a bioadhesive excipient, which would therefore confer its bioadhesive properties to the intranasal preparation to enhance the retention time between the absorbing mucosa and the drug and hence increase nasal drug absorption. This excipient was therefore selected as the ideal for use in the formulation of the intranasal preparation. The aqueous solubility of a drug plays an important role in nasal administration since it is required that the drug component be applied in a limited volume of about 200pl. To enhance the aqueous solubility of the sparingly water-soluble cyclizine HCl, a lactate salt was synthesised and characterised. This compound was found to be highly soluble in water. The intranasal preparation was therefore manufactured using the lactate form of cyclizine. A single blind study was conducted to determine and compare the pharmacokinetic parameters for both Valoid oral tablets containing 100mg cyclizine HCl (reference drug) and cyclizine lactate intranasal preparation 125mglml (study drug). The results obtained indicated a significant improvement in the bioavailability of cyclizine. For oral administration Cmax = 200.79ng/ml at tmax = 5.57h and for the intranasal preparation Cmax = 5354.22ng/ml at tmax = 1.59h. A 19.2-fold increase in drug bioavailability was observed after intranasal administration (AUCin = 122860.70ng/ml/h) compared with oral administration (AUCpo = 5943.48ng/ml/h). This enhanced bioavailability through nasal administration indicated that enhanced nasal drug absorption and hence increased bioavailability not only depends on the favourable anatomical and physiological characteristics of the nasal mucosa but possibly on the inherent physico-chemical characteristics of the drug molecule and the formulation components. Thus chemical modification of the sparingly water-soluble cyclizine HCl to the highly water-soluble cyclizine lactate facilitated the dissolution of more solute in a limited volume of solvent. This new feature therefore may have impacted positively to the transport of cyclizine across the nasal mucosa. Furthermore, the hydroxypropylmethyl cellulose (HPMC), component of the formulation, could have conferred its mucoadhesive properties to the preparation. Perhaps it increased the retention time of the dosage form within the nasal passages through bond formation with the nasal mucosa thereby increasing the contact time between the absorbing mucosa and the dosage form. This interaction between the mucoadhesive and the nasal mucosa may have resulted in the modification of tissue permeability (possibly transient opening of the tight junctions) and eventual increase in the drug penetration/absorption. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2004.

A comprehensive review of the nasal route of administration, in particular the nasal drug delivery system has been presented. The physicochemical properties, mode of action and pharmacology of H1-receptor antagonists, in particular cyclizine HCl, have been highlighted. The techniques for the assessment of toxicity (in-vitro ciliary beat frequency (CBF) studies for human nasal explants and morphology studies of the rat nasal mucosa), synthesis of cyclizine lactate, solubility studies of both cyclizine HCI and cyclizine lactate, viscosity determination of the gel formulated and assessment of the deposition and distribution of the hydroxypropylmethyl cellulose (HPMC) dispersions within the human nasal cavity model were conducted. In this study, preliminary studies on the toxicity of the various formulation components (excipients and active ingredient) were carried out. Results from these studies indicated that for both the excipients and the drug, pH significantly affects the ciliary motility hence all ciliary beat frequency determinations were conducted at nasal pH. Furthermore, effects of the various concentrations (0.0625%(w/v), 0.125%(w/v), 0.25%(w/v), 0.5%(w/v) and l%(w/v)) of the excipients on ciliary motility were investigated. Transmission electron microscopy (TEM) studies proved useful in evaluating the integrity and changes in the surface morphology of the rat nasal mucosa post treatment with the various excipients (carboxymethyl cellulose, hydroxypropylmethyl cellulose, trimethyl chitosan 36.3% DQ, Carbopol P934 and polysorbate-80) at varying concentrations. Of the excipients investigated, hydroxypropylmethyl cellulose (HPMC) showed ciliofriendliness since there was no apparent ultra structural damage, although a slight decrease in ciliary beat frequency (CBF) was observed at the highest viscosity. Moreover, hydroxypropylmethyl cellulose (HPMC) is said to be a bioadhesive excipient, which would therefore confer its bioadhesive properties to the intranasal preparation to enhance the retention time between the absorbing mucosa and the drug and hence increase nasal drug absorption. This excipient was therefore selected as the ideal for use in the formulation of the intranasal preparation. The aqueous solubility of a drug plays an important role in nasal administration since it is required that the drug component be applied in a limited volume of about 200pl. To enhance the aqueous solubility of the sparingly water-soluble cyclizine HCl, a lactate salt was synthesised and characterised. This compound was found to be highly soluble in water. The intranasal preparation was therefore manufactured using the lactate form of cyclizine. A single blind study was conducted to determine and compare the pharmacokinetic parameters for both Valoid oral tablets containing 100mg cyclizine HCl (reference drug) and cyclizine lactate intranasal preparation 125mglml (study drug). The results obtained indicated a significant improvement in the bioavailability of cyclizine. For oral administration Cmax = 200.79ng/ml at tmax = 5.57h and for the intranasal preparation Cmax = 5354.22ng/ml at tmax = 1.59h. A 19.2-fold increase in drug bioavailability was observed after intranasal administration (AUCin = 122860.70ng/ml/h) compared with oral administration (AUCpo = 5943.48ng/ml/h). This enhanced bioavailability through nasal administration indicated that enhanced nasal drug absorption and hence increased bioavailability not only depends on the favourable anatomical and physiological characteristics of the nasal mucosa but possibly on the inherent physico-chemical characteristics of the drug molecule and the formulation components. Thus chemical modification of the sparingly water-soluble cyclizine HCl to the highly water-soluble cyclizine lactate facilitated the dissolution of more solute in a limited volume of solvent. This new feature therefore may have impacted positively to the transport of cyclizine across the nasal mucosa. Furthermore, the hydroxypropylmethyl cellulose (HPMC), component of the formulation, could have conferred its mucoadhesive properties to the preparation. Perhaps it increased the retention time of the dosage form within the nasal passages through bond formation with the nasal mucosa thereby increasing the contact time between the absorbing mucosa and the dosage form. This interaction between the mucoadhesive and the nasal mucosa may have resulted in the modification of tissue permeability (possibly transient opening of the tight junctions) and eventual increase in the drug penetration/absorption. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2004.

Typewritten copy / Includes bibliographical references (leaves 141-144) / [5], 144 leaves : ill. ; 27 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / An account of experimental investigations carried out from January 1952 to September 1954. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1956