Julie I. Haynes

The relationship of the number of Meissner's corpuscles to dermatoglyphic characters and finger size

This study investigated the relationships between the density of Meissners corpuscles and the dermatoglyphic characteristics of human fingers. Dermatoglyphic prints and tissue samples were collected from the index (II) and ring (IV) fingers of 28 cadavers from the Medical School, University of Adelaide. Pattern types, pattern intensity, total ridge count and ridge breadth, were determined for each sample and the density of Meissners corpuscles established by recording the mean number of Meissners corpuscles underlying a 10 mm long line on the skin surface. No relationship was found between the density of Meissners corpuscles and pattern type, pattern intensity or total ridge count. Negative correlations were found for the density of Meissners corpuscles with both ridge width and size of fingers. Males were found to have significantly larger fingers, larger ridge breadth, and a lower density of Meissners corpuscles per 10 mm compared with females. However, there was no difference between the total number of Meissners corpuscles per finger in males and females. No significant differences were found in either the density of Meissners corpuscles between antimeres or between the index and ring fingers. These results suggest that for both the left and right hand in males and females, there is a similar number of Meissners corpuscles for both the index and ring fingers.

Immunohistochemical labeling of normal melanocytes

Comparison of seven antibodies for the demonstration of normal melanocytes in formalin-fixed, paraffin-embedded surgical discard skin showed that the monoclonal antibody Mel-5 (clone TA99) directed against pigment associated antigen was the most sensitive. Quantitative data were obtained for the sensitivity of the antibodies NKI/beteb, S100, T311, Melan A (clone A103), c-kit, and Mel-5 in parallel sections of human skin. An anticytokeratin antibody (CK34&bgr;E12) was also used to stain basal keratinocytes and provide a negative image of the melanocytes present. Optimal conditions for the use of Mel-5 in paraffin sections of skin are described.

The marsupial and monotreme thymus, revisited

The anatomy and histology of the thymus in monotremes and marsupials were revisited and several new observations made. Tissues of the mediastinum and/or ventral neck of 134 animals altogether (12 Australian marsupial and monotreme species) were examined and the locations of thymic tissues documented. Descriptions not previously recorded include the gross anatomy of the thymus in monotremes, the bandicoot ( Isoodon macrourus , Isoodon obesulus ), the wombat ( Lasiorhinus latifrons ), and koala ( Phascolarctos cinereus ), as well as light and electron microscopic features in all species examined. In monotremes, thymic tissue was diffusely spread in the mediastinum and extended over the ventral surface of the pericardium. In the bandicoot, a small, deep cervical thymus was persistently present as well as the expected thoracic thymus and contrary to previous observations, a thoracic thymus was found in the wombat but not the koala. Both species also have a cervical thymus. In the marsupial species examined, additional thymic tissue was often present in the vicinity of the carotid bifurcations, in the deep ventral regions of the neck. In many animals, thymic tissue of deep cervical origin as well as thoracic thymus was mingled with parathyroid tissue. In several specimens, the two tissue types lacked intervening connective tissue barriers and at the electron microscopic level, attenuated processes of epithelial reticular cells were the only tissue components separating parathyroid and thymic tissues. The role of the cervical thymus in diprotodont marsupials remains to be elucidated. The presence of aberrant thymic tissue in marsupials is important in the interpretation of experiments involving thymectomy and immunological development because complete removal of thymic tissue may not occur. One aspect that has received little attention is the function of the thymic epithelial reticular cells in marsupial development and a suggestion is made that perhaps the extra thymic tissue found in marsupials provides extra epithelial reticular cells necessary for the production of cytokines and other secretions to sustain the development of immunological competence.

Parathyroids and Ultimobranchial Bodies in Monotremes

Only scant information is available in the scientific literature on the parathyroids and ultimobranchial bodies in the primitive mammals, the echidna (Tachyglossus aculeatus) and platypus (Ornithorhynchus anatinus). The major aim of this paper is to describe the morphology of the monotreme parathyroid gland and to compare it with parathyroids in mammals and reptiles. The gross anatomy and light microscopic structure of the ultimobranchial body, thymus, and thyroid are also given.

Pathological Features of Oxalate Nephrosis in a Population of Koalas (Phascolarctos cinereus) in South Australia

The wild and captive koala population of the Mt Lofty Ranges in South Australia has a high level of renal dysfunction in which crystals consistent with calcium oxalate have been observed in the kidneys. This study aimed to describe the pathological features of the renal disease in this population, confirm the composition of renal crystals as calcium oxalate, and determine whether any age or sex predispositions exist for this disease. A total of 51 koalas (28 wild rescues, 23 captive) were examined at necropsy, of which 28 (55%) were found to have gross and/or histological evidence of oxalate nephrosis. Histopathological features included intratubular and interstitial inflammation, tubule dilation, glomerular atrophy, tubule loss, and cortical fibrosis. Calcium oxalate crystals were demonstrated using a combination of polarization microscopy, alizarin red S staining, infrared spectroscopy, and energy-dispersive X-ray analysis with scanning electron microscopy. Uric acid and phosphate deposits were also shown to be present but were associated with minimal histopathological changes. No significant differences were found between the numbers of affected captive and wild rescued koalas; also, there were no sex or age predispositions identified, but it was found that oxalate nephrosis may affect koalas <2 years of age. The findings of this study suggest that oxalate nephrosis is a leading disease in this koala population. Possible causes of this disease are currently under investigation.

Leaf oxalate content of Eucalyptus spp. and its implications for koalas (Phascolarctos cinereus) with oxalate nephrosis

Abstract. Oxalate nephrosis is a leading disease of the Mount Lofty Ranges koala population in South Australia, but the cause is unclear. In other herbivorous species, a common cause is high dietary oxalate; therefore this study aimed to determine the oxalate content of eucalypt leaves. Juvenile, semimature and mature leaves were collected during spring from eucalypt species eaten by koalas in the Mount Lofty Ranges and compared with those from Moggill, Queensland, where oxalate nephrosis has lower prevalence. Total oxalate was measured as oxalic acid by high-performance liquid chromatography. The oxalate content of eucalypts was low (<1% dry weight), but occasional Mount Lofty leaf samples had oxalate levels of 4.68–7.51% dry weight. Mount Lofty eucalypts were found to be higher in oxalate than those from Queensland (P < 0.001). In conclusion, dietary oxalate in eucalypt leaves is unlikely to be the primary cause of oxalate nephrosis in the Mount Lofty koala population. However, occasional higher oxalate levels could cause oxalate nephrosis in individual koalas or worsen disease in those already affected. Further studies on the seasonal variation of eucalypt leaf oxalate are needed to determine its role in the pathogenesis of oxalate nephrosis in koalas.

Plasma biochemistry and urinalysis variables of koalas (Phascolarctos cinereus) with and without oxalate nephrosis

BACKGROUND Oxalate nephrosis is a highly prevalent disease in the Mount Lofty Ranges koala population in South Australia, but associated clinicopathologic findings remain undescribed. OBJECTIVES The aims of this study were to determine plasma biochemical and urinalysis variables, particularly for renal function and urinary crystal morphology and composition, in koalas with oxalate nephrosis. METHODS Blood and urine samples from Mount Lofty Ranges koalas with oxalate nephrosis were compared with those unaffected by renal oxalate crystal deposition from Mount Lofty and Kangaroo Island, South Australia and Moggill, Queensland. Plasma and urine biochemistry variables were analyzed using a Cobas Bio analyzer, and urinary oxalate by high-performance liquid chromatography. Urinary crystal composition was determined by infrared spectroscopy and energy dispersive X-ray analysis. RESULTS Azotemia (urea > 6.6 mmol/L, creatinine > 150 μmol/L) was found in 93% of koalas with oxalate nephrosis (n = 15). All azotemic animals had renal insufficiency (urine specific gravity [USG] < 1.035), and in 83%, USG was < 1.030. Koalas with oxalate nephrosis were hyperoxaluric compared with Queensland koalas (P < .01). Urinary crystals from koalas with oxalate nephrosis had atypical morphology and were composed of calcium oxalate. Mount Lofty Ranges koalas unaffected by renal oxalate crystal deposition had renal insufficiency (43%), although only 14% had USG < 1.030 (n = 7). Unaffected Mount Lofty Ranges and Kangaroo Island koalas were hyperoxaluric compared with Queensland koalas (P < .01). CONCLUSIONS Koalas with oxalate nephrosis from the Mount Lofty Ranges had renal insufficiency, hyperoxaluria, and pathognomonic urinary crystals. The findings of this study will aid veterinary diagnosis of this disease.

Seasonal variation in occurrence of oxalate nephrosis in South Australian koalas (Phascolarctos cinereus)

Many koalas (Phascolarctos cinereus) in the Mount Lofty Ranges, South Australia, are affected by oxalate nephrosis, in which renal calcium oxalate deposition occurs. In other species, suboptimal water intake increases the risk of urinary calcium oxalate crystal formation. Koalas principally rely on eucalypt leaf moisture content to maintain hydration but the Mount Lofty Ranges region has hot, dry summers. This study investigates the association between temperature, rainfall and eucalypt leaf moisture and the occurrence of oxalate nephrosis in this population of koalas. Koalas from the Mount Lofty Ranges population that had died or were euthanased between 2008 and 2016 were necropsied and oxalate nephrosis was determined by histopathology (n = 50). Leaf moisture content of Mount Lofty eucalypts was determined seasonally. It was found that increased numbers of koalas with oxalate nephrosis died in the months following high mean maximal temperature and in the months following low rainfall. Eucalypt leaf moisture content was not significantly associated with koala deaths. These findings suggest that hot and dry summer/autumn periods contribute to an increased incidence of koala deaths due to oxalate nephrosis. This is probably due to the effects of evaporative water loss and/or lack of access to supplementary drinking water at this time.