Neurotoxicity with persistent unilateral ophthalmoplegia from envenoming by a wild inland taipan (Oxyuranus microlepidotus, Elapidae) in remote outback South Australia

© Crown. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (July 2017) in accordance with the publisher’s archiving policyIntroduction: A case of life threatening envenoming by a wild specimen of the inland taipan, Oxyuranus microlepidotus, is described. There have been 11 previously well-documented envenomings by O. microlepidotus, but only 2 were inflicted by wild snakes. Envenomed patients have presented predominantly with defibrinating coagulopathy and neurotoxicity. Case report: The victim was seeking to observe members of an isolated population of this species and was envenomed while attempting to photograph an approximately 1.5 m specimen. He reported feeling “drowsiness” and blurred vision that progressed to ptosis; he later developed dysphagia and dysarthria. The patient was treated with 1 vial of polyvalent antivenom, which was later followed with an additional two vials of taipan monovalent. He was intubated during retrieval, and recovered after 3 days of intensive care. He had a right ophthalmoplegia that persisted for approximately 1 week post-envenoming. Despite a positive 20-min whole blood clotting test, defibrination coagulopathy was absent, and there was no myotoxicity, or acute kidney injury. Discussion: Physicians presented with a patient envenomed by O. microlepidotus should remain cognizant of the possible variability of medically important venom toxins in some populations of this species. Some patients seriously envenomed by this species may develop persistent cranial nerve palsies. When clinically indicated, prompt provision of adequate antivenom is the cornerstone of managing O. microlepidotus envenoming. Rapid application of pressure-bandage immobilization and efficient retrieval of victims envenomed in remote locales, preferably by medically well-equipped aircraft, probably improves the likelihood of a positive outcome

Macroscopic Appearance, Microhardness and Microradiographic Characteristics of Experimentally Produced Fluorotic Lesions in Sheep Enamel

Fluorotic lesions resembling those seen in human teeth were produced experimentally in the unerupted enamel of the central incisor teeth of 3 sheep by daily dosing for 21 days with 2, 4 or 6 mg fluoride/kg body weight. Opacities, both superficial and extending to the amelodentinal junction, horizontal lines and pits were seen on the specimens. A comparison between the sheep with the lowest and highest dosing showed that, at these fluoride levels and given for a relatively short period of tooth development, there was no clear correlation between fluoride intake and the type of fluorosis found. The opacities and the bases of the scattered pits showed consistently lower hardness values than the surrounding enamel and in addition, the mineral content of the opacities was significantly lower than that of the control enamel. These findings support the theory that fluorotic lesions may be both pre-eruptive or post-eruptive (traumatic) in origin

The Pattern of Mineralization of Traumatically-induced Developmental Defects of Sheep Enamel Assessed by Microhardness and Microradiography

An earlier study showed that some of the variation in appearance of defects of enamel in sheep incisor teeth induced by trauma during tooth development was related to the phase of activity of the ameloblasts at the time of injury. In the present study, sixteen selected defects were examined by microhardness and microradiography. It was found that in some of the fully formed teeth, the defects had retained the pattern of mineralization present at the time of trauma, i.e., mineralization had ceased. In other teeth, further mineralization of the defects occurred after trauma, resulting in well-mineralized enamel, although sometimes of incomplete thickness. It was concluded that the trauma, depending on its severity, leads to either permanent or temporary dysfunction of the ameloblasts, which also influences the appearance of the resulting lesions

Variation in radiographic caries diagnosis and treatment decisions among university teachers

Twelve duplicated bitewing radiographs of clinical quality were viewed under controlled conditions by 42 dentists in a teaching department. The dentists noted surfaces with initial caries or with caries in need of treatment. The radiographs were rediagnosed by 20% of the dentists to determine inter- and intra examiner reliability. A norm for the validity of lesion presence in enamel or dentin was applied. The variation in surfaces indicated for treatment is illustrated by: mean 40, s.d. 16, min. 13 and max. 89 for the 42. The mean proportion of true positive filling decisions in percentages was 67, s.d. 18, the mean proportion of false positive filling decisions was 22, s.d. 22. A large individual variation was found in this study. The dental teachers saw less caries present than the norm but some indicated more fillings needed than dentin caries present. It is suggested that care in the educational process should be given to developing appropriate caries treatment criteria. Factors conducive to preventively orientated treatment decisions in the clinical situation need further attention

Diffusion of carbon-14-labeled formocresol and glutaraldehyde in tooth structures

14C-Formocresol and 14C-glutaraldehyde were placed in the root canals of freshly extracted human teeth. The outward diffusion of labeled aldehydes was then measured and autoradiograms of cross-sections taken. No diffusion of glutaraldehyde was detectable within 72 hours, whereas there was a rapidly increasing outflow of formocresol during the same period. In a separate group normal root canal treatment was completed until 2 mm. short of the roentgenologic apex with glutaraldehyde as an irrigant. The walls of the root canals of some of the specimens were examined with electron microscopy and the outflow of 14C-formocresol which was later placed in some specimens was counted. The use of glutaraldehyde as an irrigant resulted in closure of the apical third of the root canal as indicated by the absence of 14C-formocresol diffusion