Thesis (MScMedSc (Biomedical Sciences. Anatomy and Histology)--Stellenbosch University, 2008.

Two small streams on Vancouver Island, British Columbia, were examined for patterns of morphological variation in Gasterosteus aculeatus. A progressive analysis beginning with Principle Components Analysis, followed by Nested and Partially Nested Multiple Analysis of Variance and then Duncan's Multiple Range Test was used for pattern determination. This new technique allows the researcher to sequentially isolate the pattern of variation at different levels of generality from species to individual organisms. The pattern of variation for G. aculeatus in Bonsall Creek and Nunns Creek can be summarized as follows: The largest amount of variation accounted for by the analysis is interpreted as individual variation. Populations also account for a large amount of variation and show consistent, fully nested patterns of variation at each of the analysed geographic and microgeographic levels. These populations are probably genealogical units. The so-called "leiurus" and "trachurus" forms on the Pacific coast of North America do not appear to be evolutionary entities, but to be historical artifacts that are best viewed as labels for the extremes of a continuum of variation. In areas where distinct populations meet, different clines are documented in the two stream systems. In Nunns Creek there is a smooth cline between populations, whereas in Bonsall Creek there is a step cline. / Science, Faculty of / Zoology, Department of / Graduate

This project examined the role of the cytoskeleton in regulatory mechanisms of the amiloride-sensitive Na⁺ channels in isolated frog skin epithelium. The epithelium from ventral frog skin is a model tissue which has proved significant in our understanding of the basic principles involved in water and Na⁺ homeostasis. In particular, this project examines ways in which local (non-hormonal) and hormonal regulatory mechanisms adjust the Na⁺ permeability of apical membranes of frog skin epithelium. Both mechanisms contain factors that are known to increase the apical membrane Na⁺ permeability mainly by increases in the number of open channels. The origin of these new open channels is unknown but, it is postulated that they could arise either by activation of quiescent channels already present in the apical membrane, or by recruitment of channels from cytoplasmic stores. Regarding the latter hypothesis, we also examined the idea that the cytoskeleton might somehow be involved in the insertion of Na⁺ channels within vesicles, into the apical membrane. This is based on the fact that the cytoskeleton is involved in a similar mechanism whereby, in the toad urinary bladder, anti-diuretic hormone (ADH) causes the insertion of aggregates with water channels. Much current interest focuses on the role of the cytoskeleton in the regulation of epithelial Na⁺ channels. To test this hypothesis, we used noise analysis to examine the effects of disrupting the cytoskeleton, on two different mechanisms which bring about changes in open channel densities. The mechanisms are: (1) lowering mucosal Na⁺ concentration (non-hormonal), and (2) addition of arginine-vasopressin (A VP) (hormonal). Non-hormonal, autoregulatory changes in apical membrane Na⁺ conductance were examined by investigating the effects of reducing the mucosal Na⁺ concentration. Our results showed that lowering the mucosal Na⁺ concentration induced large increases in the open channel density in order to stabilise the transport rate. In addition, we observed an average 55-60% increase in the open channel probability, which implies that in epithelium from Rana fuscigula, changes of channel open probability are also an important mechanism in the autoregulation of channel densities in response to a reduction in mucosal Na⁺. The hormonal control of Na⁺ channels by A VP has been intensively studied by noise analysis and the patch clamp. Our results confirmed previous reports that A VP increases the Na⁺ transport rate by increasing the number of open Na⁺ channels, primarily through large changes in the total number of channels, without a significant change in open probability. Regarding the role of the cytoskeleton in regulation of Na⁺ channels and/or its possible role in control of inserting putative vesicles with Na⁺ channels, we studied the effects of disrupting the cytoskeleton on the two regulatory mechanisms. Disrupting microtubules with colchicine had no, or very little effect on either of the regulatory mechanisms. On the other hand, the integrity of the microfilaments was very important for the autoregulatory changes in the number of open channels. After cytochalasin B treatment, lowering the mucosal Na⁺ concentration did not result in the usual compensatory changes in channel densities. There was no prior evidence that cytochalasin B had any actual effect on the F-actin network in the frog skin epithelium. Accordingly, modified cytochemical techniques were designed to demonstrate and localise F-actin in the epithelial granular cells. The direct immunofluorescent method proved useful, but did not allow sufficient resolution to examine the changes to different populations of actin in the cells. We then modified an immunogold method to suit our conditions, and the results demonstrated the localisation of different pools of F-actin and showed the effects of the cytochalasin B and vasopressin.

Indiana University-Purdue University Indianapolis (IUPUI) / Tooth mass discrepancies have been studied extensively in Caucasian populations, but little has been done to compare differences between Caucasian and African-American populations. The objective of this study was to determine whether the incidence of tooth mass discrepancies between the maxillary and mandibular arches was greater in African-American populations than Caucasian populations. Pretreatment plaster orthodontic models of 100 African-American and 100 Caucasian patients from the Indiana University Orthodontic Clinic and from one private practitioner were measured with a Mitutoyo Digimatic® caliper accurate to 0.01 mm. Mesiodistal widths of all teeth from first molar to first molar were measured with the mesio-buccal and disto-buccal contact areas normally being the widest area. The investigator was blinded to the gender and ethnicity of the subject by assigning each model a random number which was matched to the patient profile only following statistical analysis. Anterior ratios and total (posterior+ anterior) ratios were calculated according to the methods described by Bolton and were compared to the Bolton means and standard deviations. Incidence of tooth mass discrepancy was also investigated according to gender and dental malocclusion classification of the individuals. Tooth mass discrepancies present a hurdle to the clinician in achieving an ideal occlusion. Reports of the incidence of significant discrepancies in defined populations alerts the practitioner to problems in finishing their patients' occlusions. Results of the study show nearly double the incidence of overall Bolton tooth mass discrepancy in the African-American sample than in the Caucasian. The overall tooth mass discrepancy was more severe in the African-American sample, while anterior tooth mass discrepancies were nearly identical in both populations.

by Yim-kam Kwong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 119-133). / ACKNOWLEDGEMENT --- p.vii / LIST OF TABLES --- p.viii / LIST OF FIGURES --- p.x / ABSTRACT --- p.1 / SECTION / Chapter 1. --- INTRODUCTION --- p.3 / Chapter 2. --- LITERATURE REVIEW --- p.6 / Chapter 3. --- MATERIALS AND METHODS --- p.39 / Chapter 4. --- RESULTS --- p.61 / Chapter 5. --- DISCUSSION --- p.103 / Chapter 6. --- CONCLUSION --- p.116 / REFERENCES --- p.119 / APPENDIX --- p.134 / Chapter SECTION 1 --- INTRODUCTION --- p.3 / Chapter SECTION 2 --- LITERATURE REVIEW --- p.6 / Chapter 2.1 --- IRON --- p.6 / Chapter 2.1.1 --- CHEMISTRY --- p.6 / Chapter 2.1.2 --- METABOLISM --- p.6 / Chapter 2.1.2.1 --- Homeostasis --- p.6 / Chapter 2.1.2.2 --- Absorption --- p.8 / Chapter 2.1.2.3 --- Transportation - Role of transferrin in iron transport --- p.9 / Chapter 2.1.2.4 --- Storage --- p.10 / Ferritin --- p.11 / Haemosiderin --- p.13 / Chapter 2.2 --- IRON OVERLOAD --- p.14 / Chapter 2.2.1 --- AETIOLOGY --- p.14 / Chapter 2.2.2 --- PREVALENCE --- p.15 / Chapter 2.2.3 --- MECHANISM --- p.16 / Chapter 2.2.4 --- PATHOLOGY OF IRON OVERLOAD --- p.17 / Chapter 2.2.4.1 --- Increased absorption of iron from the diet --- p.18 / Chapter 2.2.4.2 --- Parenteral administration of excess iron --- p.21 / Chapter 2.2.4.3 --- Increased iron absorption combined with transfusional overload --- p.22 / Chapter 2.2.4.4 --- Miscellaneous conditions --- p.23 / Chapter 2.2.5 --- CLINICAL PRESENTATION --- p.24 / Chapter 2.2.6 --- EFFECT OF IRON OVERLOAD --- p.25 / Chapter 2.2.6.1 --- Role of iron in lipid peroxidation --- p.25 / Chapter 2.2.6.2 --- Iron and neoplasia --- p.26 / Chapter 2.3 --- ASSESSMENT OF IRON OVERLOAD --- p.26 / Chapter 2.3.1 --- NON-SERUM PARAMETER --- p.26 / Chapter 2.3.1.1 --- Localization of stored iron --- p.27 / Chapter 2.3.1.2 --- Morphometric assessment of hepatic iron in liver biopsy --- p.30 / Chapter 2.3.1.3 --- Hepatic iron concentration --- p.31 / Chapter 2.3.1.4 --- Atomic absorption spectrophotometry --- p.32 / Chapter 2.3.1.5 --- Hepatic imaging studies --- p.33 / Chapter 2.3.2 --- SERUM PARAMETERS --- p.34 / Chapter 2.3.2.1 --- Serum ferritin measurement --- p.34 / Chapter 2.3.2.2 --- Serum iron --- p.36 / Chapter 2.3.2.4 --- Transferrin saturation --- p.37 / Chapter SECTION 3 --- MATERIALS AND METHOD --- p.39 / Chapter 3.1 --- SUBJECTS --- p.39 / Chapter 3.1.1 --- SOURCE OF TISSUE SAMPLES AND CASE SELECTION --- p.39 / Chapter 3.1.1.1 --- The controls --- p.39 / Chapter 3.1.1.2 --- The transfusion group --- p.39 / Chapter 3.1.1.3 --- The non-transfusion group --- p.40 / Chapter 3.1.1.4 --- The total group --- p.40 / Chapter 3.2 --- METHODS --- p.40 / Chapter 3.2.1. --- HISTOLOGICAL METHOD --- p.44 / Chapter 3.2.1.1 --- Haematoxylin and Eosin Stain --- p.47 / Chapter 3.2.1.2 --- Perls' Prussian Blue Method --- p.49 / Chapter 3.2.1.3 --- The Rowe's Method of Iron Deposition --- p.47 / Chapter 3.2.1.4 --- Method 1 --- p.48 / Chapter 3.2.1.5 --- Method2 Estimation and grouping of % area --- p.49 / Chapter 3.2.1.6 --- "Comparison of Rowe's method, and the two histological iron grading methods" --- p.54 / Chapter 3.2.2 --- CHEMICAL MEASUREMENT --- p.55 / Chapter 3.2.2.1 --- Sectioning of paraffin liver blocks for chemical measurement --- p.55 / Chapter 3.2.2.2 --- Paraffin removal --- p.56 / Chapter SECTION 4 --- RESULTS --- p.61 / Chapter 4.1 --- HISTOLOGICAL ASSESSMENT --- p.61 / Chapter 4.1.1 --- HISTOLOGICAL STUDY --- p.61 / Chapter 4.1.2 --- SEX DISTRIBUTION --- p.65 / Chapter 4.1.3 --- AGE DISTRIBUTION --- p.65 / Chapter 4.2 --- CHEMICAL MEASUREMENT --- p.81 / Chapter 4.2.1 --- EVALUATION OF ANALYTICAL PRECISION --- p.84 / Chapter 4.2.2 --- RESULT OF CHEMICAL MEASUREMENTS --- p.81 / Chapter 4.2.3 --- ASSOCIATED CONDITIONS IN PATIENTS WITH LIVER TISSUE IRON > 50 μMOL/G --- p.86 / Chapter 4.3 --- CORRELATION OF HISTOLOGICAL ASSESSMENT WITH CHEMICAL MEASUREMENT --- p.88 / Chapter 4.3.1 --- CORRELATION OF HISTOLOGICAL ASSESSMENT WITH CHEMICAL MEASUREMENT BY METHOD 1 --- p.88 / Chapter 4.3.2 --- CORRELATION OF ASSESSMENT WITH CHEMICAL MEASUREMENT BY METHOD 2 --- p.89 / Chapter 4.3.2.1 --- Percentage area --- p.95 / Chapter 4.3.2.2 --- Score --- p.96 / Chapter 4.4 --- PANCREATIC AND MYOCARDIAC HAEMOSIDEROSIS --- p.100 / Chapter 4.4.1 --- METHOD 2 --- p.100 / Chapter SECTION 5 --- DISCUSSIONS --- p.103 / Chapter SECTION 6 --- CONCLUSIONS --- p.116 / REFERENCES --- p.119 / APPENDIX --- p.134

Joie Jie Wang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 121-132). / ABSTRACT --- p.i / ACKNOWLEDGEMENTS --- p.iii / LIST OF TABLE --- p.vii / LIST OF FIGURES --- p.viii / LIST OF ABBREVIATIONS --- p.xii / Chapter CHAPTER I. --- INTRODUCTION --- p.1 / Chapter I.1. --- Fibre tracts of the rat spinal cord --- p.1 / Chapter I.2. --- Histopathological responses to spinal cord injuries --- p.2 / Chapter I.3. --- Failure of CNS regeneration --- p.4 / Intrinsic inability of CNS neurons themselves to regenerate --- p.4 / Inappropriate synapse without normal functioning --- p.5 / Progressive necrosis and cystic cavities --- p.5 / Autoimmune explanation for the failure of regeneration --- p.6 / Glial scarring --- p.6 / Absence of Schwann cells in the CNS --- p.7 / Lack of requisite growth factors --- p.8 / Chapter I.4. --- The use of transplants --- p.9 / Transplants of fetal nerve tissues --- p.9 / Transplants of peripheral nerve tissues --- p.10 / Transplants of neuroglial cells --- p.11 / Transplants of central neurons --- p.12 / Chapter I.5. --- Objectives of the present study --- p.13 / Chapter CHAPTER II. --- METERIALS AND METHODS --- p.15 / Chapter II.1. --- Hemisection of rats --- p.15 / Chapter II.2. --- Preparation of purified cortical astrocytes --- p.15 / Chapter II.3. --- Scanning electron microscopy (SEM) --- p.18 / Chapter II.4. --- HistologýؤLight microscopy --- p.19 / Chapter II.5. --- Measurement of volume of scar tissue --- p.19 / Chapter II.6. --- Immunofluorescence staining --- p.20 / Chapter II.7. --- Transmission electron microscopy --- p.23 / Chapter II.8. --- Comparison of expression of various proteins in the spinal cord --- p.24 / Polyacrylainide gel electrophoresis --- p.24 / Western blotting --- p.26 / Chapter CHAPTER III. --- RESULTS --- p.28 / Chapter III.1. --- Survival of cultured astrocytes --- p.28 / Chapter III.2. --- Light microscopy --- p.28 / Hemotoxylin and Eosin staining --- p.28 / Toluidine Blue staining --- p.30 / PHAL labelled astrocytes --- p.31 / Immunofluorescence staining --- p.32 / N-CAM --- p.32 / GFAP --- p.33 / NF --- p.34 / Chapter III.3. --- Transmission electron microscopy (TEM) --- p.35 / Chapter III.4. --- Determination of the volume of scar tissue --- p.37 / Chapter III.5. --- Gel electrophoresis --- p.38 / Chapter III.6. --- Immunoblotting and densitometry --- p.38 / Chapter CHAPTER IV. --- DISCUSSION AND CONCLUSIONS --- p.115 / REFERENCES --- p.121

Anomalodesmatans comprise a large, ancient and ecologically diverse group of marine bivalves, but are nonetheless inconspicuous in most extant shallow water communities. For various reasons, which include their present scarcity and a bewildering array of disparate morphologies, representatives of the group have always proved difficult to interpret, and their systematics lagged behind those of most other major bivalve taxa. Most of this dissertation reports the results of a comparative investigation on the shell morphology and anatomy of extant anomalodesmatans, which formed the basis for a reassessment of hypotheses of primary homology established by previous investigators and identification of novel characters for phylogenetic inference. Due to the chief role played by the hinge ligament in authoritative discussions of anomalodesmatan evolution, this organ was chosen as the focus of a more detailed treatment. Discontinuous ontogeny of fibrous ligament is shown to characterise several members of the group, with the implication that, in contrast to the prevailing model,not all anomalodesmatan adult ligaments may be considered homologous. Likewise, a system of multicellular glands concerned with sediment agglutination was studied with particular emphasis because it is both exclusive to and widespread within Anomalodesmata. Evidence of preserved glandular secretion is recorded for the first time in fossil material and the glands themselves found in extant laternulids and pholadomyids, thus considerably expanding their known taxonomic distribution. Finally, this volume also documents the largest cladistic analysis of extant anomalodesmatans performed to date, including morphological data compiled from both original observations and literature accounts. Among traditionally recognised superfamilies, Pholadomyoidea, Clavagelloidea and Septibranchia were found monophyletic. Taxa commonly referred to Pandoroidea and Thracioidea were recovered as part of two new clades, which are also supported by recent molecular studies. Interpreted in the light of the fossil record, reconstructed phylogenetic relationships favour the iterative evolution of shallow infaunal and epifaunal anomalodesmatans from deep-burrowing ancestors over previously advanced patterns for the history of the clade, namely ventral migration of the ligament and irreversible radiations into a deep infaunal life habit.

A study of the digestive tract of the copepods Tigriopus californicus and Calanus plumchrus was carried out using techniques of light and electron microscopy. In Tigriopus californicus, the foregut contains a curved cuticle lined esophagus which extends from the ventral mouth to the junction of the anterior midgut and midgut caecum. The noncuticulized portion of the digestive tract consists of: 1. A single spherical midgut caecum located anteriorly, 2. An anterior midgut, 3. A posterior midgut. There are cuticulized anterior and posterior hindgut regions ending in a dorsal anus. In Calanus plumchrus, the foregut consists of a cuticle lined esophagus extending from the ventral mouth to the junction of the midgut and the midgut diverticulum. The noncuticulized portion of the digestive tract consists of: 1. A single midgut diverticulum, 2. A midgut that is divisible on the basis of epithelial cell type and function. There is a long abruptly narrowing cuticle lined hindgut ending in an anus. In Tigriopus californicus, four cell types could be distinguished and from such ultrastructural characteristics as the position in the digestive tract, abundance, position, and type of organelles, lipid content, presence and type of vesiculation, and electron density, functions for the cells were determined. Cell type '1' is an embryonic 'stem' cell. It functions as a replacement cell and differentiates when cells are worn away or lost in secretion. Cell type '2' is mainly a secretory cell and functions in the synthesis of proteins. It also plays a role in lipid absorption. Cell type '3' is absorptive, mainly for lipids. Cell type M1, found only in the anterior midgut is also an absorptive cell. The presence of electron dense vesicles suggests that lipid absorption is not its major function. From the abundance of cell type and from examination of the ultrastructure in the various regions of the digestive tract, the following conclusions were made: 1. The midgut caecum functions in the absorption of digested nutrients. 2. The anterior midgut plays a role in nutrient absorption but is important in secretion. 3. The posterior midgut cells are mainly absorptive. In Calanus plumchrus, five cell types could be distinguished. Cell type 'E' is an undifferentiated 'stem1 cell. Cell type 'R' found in the midgut diverticulum and posterior midgut regions, is absorptive. Its developed basal surfaces suggest a transport function between the cell and the haemo-coel . Cell type 'D' is found in the glandular region of the midgut and is absorptive. It has an ultrastructure similar to that observed for cell type 'R'. Cell type 'B' is a large vacuolated absorptive cell found in the glandular region of the midgut. Cell type 'F' functions in the synthesis and secretion of digestive enzymes. In Calanus plumchrus, the midgut diverticulum is specialized for the absorption of digested nutrients and transport of metabolites to the haemocoel . The anterior midgut regions are mainly absorptive. It includes a vacuolated glandular region specialized for pinocytotic absorption. In the middle section of the midgut, adjacent and posterior to the glandular region, is an area of epithelial cells specialized for secretion. The posterior midgut regions are mainly absorptive. In Tigriopus californicus biological markers can be used to determine cell type function in correlation with the observed ultrastructure. / Science, Faculty of / Zoology, Department of / Graduate

A study on the process of bud initiation and development in the filamentous brown alga Sphacelaria furcigera (Kutz) was carried out using techniques of light and electron microscopy, as well as cytochemistry. A localized thickening and subsequent protrusion of the outer cell wall of the axial mother cell characterizes the earliest detectable stage of bud initiation. This protrusion forms through the combined deposition of newly synthesized microfibrils together with the partial lysis/loosening of the existing cell wall. Evidence is presented that of the three enzyme activities localized, peroxidase, adenosine triphosphatase and acid phosphatase activity, only peroxidase activity is related to the lysis/loosening of the cell wall during the early development of the bud initial. Continued incorporation of new cell wall material into the outer cell wall maintains its structural integrity. However, there is a change in the layered appearance of the cell wall microfibrils. The cell wall of the bud initial is characterized by two cell wall layers instead of the four found in the pre-existing cell wall of the axial mother cell. This original cell wall is composed of an outer-most fucan layer, overlying an alginate layer, which in turn overlies another fucan layer and finally terminates in an inner-most alginate layer. In contrast the bud initial's cell wall has only a thin outer fucan layer and a thick inner alginate layer. Concomitant with the formation of the cell wall protrusion, there is a loss of cytoplasmic vacuoles, an increase in cytoplasmic mass and density and an increase in the number of organelles. The endomembrane system (endoplasmic reticulum, dictyosomes and the derivative vesicles) also proliferates. Organelle migration into the bud protrusion keeps pace with bud expansion. The movement of the nucleus, however, lags behind and it migrates towards the bud protrusion only after a "vacuole free" cytoplasm becomes established. As the nucleus approaches a medial position between the base of the axial mother cell and the tip of the bud protrusion, cytoplasmic vacuoles re-appear. They are confined, however, to the basal region of the axial mother cell. After karyokinesis, a cross wall is deposited between the two daughter nuclei resulting in the formation of a bud cell and a sister axial cell. The sister axial cell is highly vacuolated and structurally resembles the adjacent quiescent axial cells. The bud cell is dense and non-vacuolated, a feature characteristic of a mefistematic cell. / Science, Faculty of / Botany, Department of / Graduate

The well-known neurological disturbances associated with caudal displacement of the cerebellar tonsils through the fora men magnum (Chiari malformation) have lead to many radiological studies of the region. With MRI, routine sagittal and parasagittal views of the craniovertebral junction have shown that the position of the cerebellar tonsils is variable, and in many otherwise healthy individuals, the inferior tonsillar margins lie within the fora men magnum itself. In some cases, this topography is associated with little signal from the surrounding cerebra-spinal fluid (CSF), indicating reduction of the cerebellomedullary cistern and, therefore, crowding of neural structures within the confines of the fora men. The objective of this study has been to examine the spatial relationship between the contents of the foramen magnum ie. the medulla and cerebellar tonsils, using a normal sample comprising 120 volunteers. Instead of the conventional measurements of distance, a ratio, the Foramen Magnum Index (FMI), has been determined, derived from the relative surface areas (pixels) of neural parenchyma and CSF, over axially and sagittaly-defined boundaries of the fora men. The FMI, with a 95th centile of 0.77, exhibits appropriate statistical correlation with tonsillar position below the level of the foramen, and is therefore considered specific. As a quantitative means of assessing the cerebellomedullary cistern, the FMI also identifies certain subjects whose tonsils are at the foramen, in whom the cistern is small with resultant neural crowding.