Nitrate-nitrite toxicity in cattle and sheep grazing Dactyloctenium radulans (button grass) in stockyards

Hungry cattle and sheep introduced to stockyards containing a dominant or pure growth of Dactyloctenium radulans (button grass) suffered acute nitrate-nitrite toxicity in four incidents in inland Queensland between 1993 and 2001. Deaths ranged from 16 to 44%. Methaemoglobinaemia was noted at necropsies in all incidents. An aqueous humour sample from one dead steer contained 75 mg nitrate/L and from one dead sheep contained 100 mg nitrate and 50 mg nitrite/L (normal = ca 5 mg nitrate/L). Both lush and dry button grass were toxic. The nitrate content of button grass from within the stockyards ranged from 4.0 to 12.9% as potassium nitrate equivalent in dry matter and from outside the stockyards ranged from <0.2 to 0.4%. These data suggest that urine and faeces in stockyard soil may boost the nitrate content of button grass to a concentration hazardous to hungry ruminants.

The Nuss procedure for pectus excavatum correction

Pectus excavatum is an anterior chest wall deformity that now can be corrected with a minimally invasive technique known as the Nuss procedure. Patient criteria and assessment for this new surgical procedure are defined clearly in advance to ensure the need for surgical intervention. A multidisciplinary team approach has been established at Children's Hospital of The King's Daughters, Norfolk, Va. Team members work cooperatively throughout the perioperative cycle, addressing not only the surgical procedure but also pain management and postoperative recovery. This dedicated team approach helps ensure a successful outcome for the patient.

Veterinary surgeon's guide to Australian bat lyssavirus

Veterinary surgeons in Australia must be aware of the emerging viral diseases and their potential effects on public health generally and, more specifically, on the veterinary profession. Australian bat lyssavirus was identified in 1996 and causes rabies-like disease in bats and humans. Two humans from Queensland have died of Australian bat lyssavirus encephalitis. Surveillance has shown that all Australian bats must be considered carriers of this new virus, therefore protective apparel should be used when handling bats. The pre-exposure regimen of inactivated rabies vaccine (Pasteur Mérieux) provides protection against infection. As part of the preventive regimen, at risk groups, such as veterinary surgeons, should seriously consider pre-exposure rabies vaccination. The post-exposure protocol involves administration of human rabies immunoglobulins and five intramuscular injections of the inactivated rabies vaccine.

Effectiveness of small workshops for improving farmers' knowledge about ovine footrot

OBJECTIVE

To determine sheep farmers' attitudes to and beliefs about ovine footrot, and to improve their knowledge about the diagnosis, control and eradication of this disease.

METHOD

Eighteen workshops, involving 291 farmers, were conducted across Victoria in the spring of 1996. The workshops were designed as small-group discussions with a maximum attendance of 20 farmers to encourage active participation. All participants completed questionnaires before each workshop and 12 to 40 weeks after the last workshop.

RESULTS

Before the workshops the farmers had a poor understanding of the principles of diagnosis, control and eradication of footrot. For example, only 50% knew the footrot organism survived in soil for less than 7 days, over two-thirds did not know the reason for paring sheep's feet during an eradication program, and only 31% realised cattle were a potential source of footrot infection for sheep. After the workshops, understanding about footrot was significantly improved; 87% said Dichelobacter nodosus survived in soil less than 7 days, 71% knew the reason for paring sheep's feet and 64% realised that cattle were a potential source of footrot infection. As well as improved knowledge, change of attitude among farmers is fundamentally important if virulent footrot is to be successfully controlled and eradicated. The workshops successfully initiated this process; 40% of farmers thought the workshops changed their attitudes to footrot, while 37% said they gained an increased understanding of other people's opinions about the disease.

CONCLUSION

Farmers' poor understanding of ovine footrot is a constraint to the programs aimed at controlling this disease. Small group workshops may be an effective way to influence farmers' attitudes and beliefs, and could facilitate the effectiveness of regulatory disease control programs.

Tube placement: a prospective, randomized double-blind study

Bilateral myringotomy with tympanostomy tube placement is the second most frequently performed pediatric surgical procedure, next to circumcision. Postoperative pain relief for children undergoing this procedure has been an ongoing concern. The authors undertook a prospective, randomized, double-blind, placebo-controlled clinical study in 200 consecutive children to investigate the efficacy of oral acetaminophen, acetaminophen with codeine, ibuprofen, and placebo administered preoperatively in relieving postoperative pain in children undergoing this procedure. All children received topical analgesia consisting of antibiotic eardrops mixed with 4% lidocaine intraoperatively. There was no significant difference in postoperative pain score between the four groups (P > 0.4447). Thus it is likely that the intraoperative administration of antibiotic eardrops mixed with 4% lidocaine is all that is required to alleviate postoperative pain in children undergoing myringotomy with tympanostomy tube placement. Preoperative oral analgesics are apparently of little added benefit.

The importance of endodontic access in locating maxillary and mandibular molar canals

The principle of straight-line access is discussed with particular reference to endodontic access of either maxillary or mandibular molar teeth. Modifications to the traditional triangular access opening are described that will make it easier for a practitioner to locate and instrument the fourth canal system commonly found in molar teeth. The high frequency of a fourth canal in molar teeth makes it essential to anticipate and find all canals during molar endodontic therapy. Quite frequently, the general practitioner attempting molar endodontic therapy should expect to locate a second canal in the mesiobuccal root of the maxillary molar and a second canal in the distal root of a mandibular molar. The possibility of extra roots over and above the norm should also be anticipated and looked for carefully. Proper angulation and interpretation of radiographs help to identify chamber and root anatomy. A two-step access opening is advocated when making access openings on molar teeth if a coronal crack in the crown is to be seen early in treatment. A method of unroofing the pulp chamber and pre-flaring the canal orifice to facilitate the subsequent shaping of the entire root-canal system is described. Clinical and laboratory examples are pictured to illustrate modifications or errors in the standard endodontic access opening.

Model for trauma outcomes management in patients with multiple trauma

Critically injured patients with chest trauma generally sustain severe life-threatening injuries. Post-operative care tends to be complex, and all aspects of care from pre-hospital through rehabilitation must be coordinated and communicated to maximize patient outcomes. The Trauma Outcomes Management Model allows clinicians to assess, track, and analyze the relationship among interventions, outcomes, and the cost of care for each phase of the trauma care continuum. This article presents the design and utilization of trauma outcome guides in the Emergency and Critical Care departments.