Development of an animal repellent — selection, efficacy and presentation

Under some circumstances it may be desirable to repel herbivorous pests (e.g. goats and wallabies) from plants (e.g. horticultural or forestry seedlings) rather than to kill them. These circumstances may include using these animals as a resource at a later time, and there may also be welfare, public perception or legislative issues where repelling animals from particular plants or area is preferable to killing them. The first experiment tested the efficacy of 5 different materials (tiger fecal extract, maggot brew — the liquid exudate from a flyblown goat, capsaicin, dog urine, and burnt goat hair, skin and carcass + fat) to repel groups of goats in a feedlot pen from 1 trough of feed when another trough of feed was available to them to eat. Each repellent was tested on 5 groups of mixed age female goats for periods of 3 days. All 5 groups were exposed to the 5 repellents. Both tiger fecal extract and maggot brew reduced intake of feed from the ‘protected’ feed trough and significantly (P<0.05) delayed ‘normal’ feeding behaviour by more than 5 h from that trough. The repellents became less effective with repeated use even with different groups of goats. The reduction in effectiveness was indicated by higher intakes of feed and earlier feeding from the protected trough. This habituation to the repellents, where the effectiveness is reduced with repeated exposure, is of concern. In the second experiment, we selected the most effective repellent (tiger fecal extract) and tested its efficacy under similar conditions, after the repellent had been mixed with a carrier (bentonite) in an endeavour to increase the duration of its effectiveness. This repellent was significantly more effective in repelling groups of 3 goats in a feedlot pen from 1 trough of feed for 3 days, when another trough of feed was available to them to eat.

Left circumflex coronary artery to left atrial fistula in a patient with mitral regurgitation after excision of a left atrial myxoma

Acquired coronary artery to left atrial fistulas are rare and previously only described in mitral stenosis associated with left atrial thrombus or coronary arteriosclerosis. We present the case of a patient who developed a left circumflex coronary artery to left atrial fistula associated with mitral regurgitation 12 years after excision of a left atrial myxoma. This was successfully ligated at the time of mitral valve replacement.

Allergic skin reactions to anticonvulsant medications in patients receiving cranial radiation therapy

PURPOSE

Erythema multiforme and Stevens-Johnson syndrome have been associated with anticonvulsant medications (AEDs) in patients with brain tumors receiving cranial irradiation. AEDs are also known to cause mild drug rashes. The incidence of these complications has not been well studied among patients with brain tumors. We reviewed the records of patients with brain tumors treated with cranial radiation and AEDs to assess the frequency of both severe and mild skin reactions.

METHODS

Retrospective review of 289 radiotherapy records of consecutively treated patients from 1988 to 1993.

RESULTS

Only one of 289 patients developed erythema multiforme. Milder rashes, however, occurred in 18% of exposures to AEDs including 22% of exposures to phenytoin, compared with the expected rate of 5-10%. Most of the mild drug rashes occurred before the initiation of radiotherapy, suggesting that radiation was not the cause of these reactions.

CONCLUSIONS

Severe skin rashes are rare among patients with brain tumors receiving radiation therapy and AEDs. There is, however, an increased frequency of mild drug rashes among patients with brain tumors that does not appear related to radiation.

The medical examiner in war

Loss of human life is one of the tragic costs of war. While combat deaths are expected, non-combat deaths during a military operation often come as a surprise to military planners and the public. During operation Desert Storm, all United States deaths related to the Gulf War were classified according to circumstances as either hostile or non-hostile. We reviewed all deaths classified as non-hostile during Operation Desert Storm, from January 16, 1991 through April 17, 1991. These deaths were compared with the death recorded for all Armed Forces personnel during a recent year (fiscal year 1989) in which there was no hostile activity. The emphasis is on cause and manner of death. Representative cases are briefly discussed.

The expanded health belief model as a basis for enlightened preventive health care practice and research

The health belief model has served as the primary theoretical vehicle for preventive health care research and practitioner guidelines for the past two decades. However, it has been criticized for its rational belief tenets. An expanded health belief model is proposed that explicitly incorporates a process orientation and adds several constructs with good potential to explain difficulties practitioners encounter in fostering realization of health risks and/or gaining long-term compliance with preventive health care recommendations. Illustrative practitioner implications are described and an agenda for research on the expanded model is outlined.

The effects of hyponatraemia and subarachnoid haemorrhage on the cerebral vasomotor responses of the rabbit

Impairment of cerebral autoregulation and development of hyponatraemia are both implicated in the pathogenesis of delayed cerebral ischaemia and infarction following subarachnoid haemorrhage (SAH) but the pathophysiology and interactions involved are not fully understood. We have studied the effects of hyponatraemia and SAH on the cerebral vasomotor responses of the rabbit. Cerebrovascular reactivity to hypercapnia and cerebral autoregulation to trimetaphan-induced hypotension were determined in normal and hyponatraemic rabbits before and 6 days after experimental SAH produced by two intracisternal injections of autologous blood. Hyponatraemia (mean plasma sodium of 119 mM) was induced gradually over 48 h by administration of Desmopressin and intraperitoneal 5% dextrose. Sham animals received normal saline. The cerebrovascular reactivity (% change +/- SD in cortical CBF/mm Hg PaCO2, measured by hydrogen clearance) of hyponatraemic (4.8 +/- 3.0%) and SAH (1.3 +/- 2.0%) animals was significantly less (p less than 0.05) than control (11.6 +/- 4.0%) and sham (8 +/- 2.0%) animals, whereas the reactivity of hyponatraemic-SAH animals was preserved (9.8 +/- 6.0%). Hyponatraemia and SAH alone each significantly impaired CBF autoregulation but their combined effects were not additive. Systemic hyponatraemia impairs normal cerebral vasomotor responses but does not augment the effects of experimental SAH in the rabbit.