Increased incidence of mixed drug toxicity deaths involving tapentadol - A forensic study

Tapentadol is a relatively new synthetic opioid analgesic prescribed for the management of moderate to severe pain. While tapentadol has been shown to be more effective than traditional opioid analgesics, it still carries the risk of addiction, abuse, and misuse. In Australia, tapentadol has become one of the top five most commonly prescribed opioid drugs, with prescriptions increasing by approximately 150,000 each year since it first became available. The rapid increase in tapentadol prescriptions has occurred in parallel to an increasing number of post-mortem tapentadol detections in South Australia (SA). While the number of deaths in SA related to tapentadol use was low in the current study, findings suggest that an increasing trend of deaths involving tapentadol will continue in parallel to a rapidly increasing number of prescriptions, mirroring trends associated with traditional opioids in SA. As a comparatively new opioid analgesic, monitoring future trends will be important to determine if additional prescribing education, intervention, or restrictions are required.

The effect of age on injury patterns in pedestrian deaths

Although it is known that elderly pedestrians are at increased risk of injury and death from vehicle crashes the specific pattern of lethal injuries related to age has not been extensively studied. Data on the numbers of pedestrian fatalities and ages were obtained from 1990 to 2020 from the Traffic Accident Reporting System, The University of Adelaide, Adelaide, South Australia and detailed autopsy data on fatal pedestrian crashes from the pathology database at Forensic Science SA, Adelaide, South Australia from 2000 to 2020. Fatal injuries were separated into the following regions: head/face, spine, chest, abdomen and limbs/skeleton. Analysis of 634 cases of pedestrian fatalities (1990-2020) showed a significant decline in numbers over the years (p < 0.001). Analysis of fatal injuries in 219 cases (2000-2020) showed a significant reduction in the proportion of fatal head injuries with increasing age (p < 0.05), a significant increase in the proportion of fatal chest injuries with increasing age (p < 0.01) and a significant increase in the proportion of fatal limb/skeletal injuries with increasing age (p < 0.05). Older pedestrians are, therefore, more likely to sustain lethal chest and limb/skeletal injuries than head injuries compared to those who are younger, presumably due to greater physical fragility that occurs with age, with loss of protective muscle bulk and bone density.

Seat belt injuries and external markings at autopsy in cases of lethal vehicle crashes

A study was undertaken to determine what injuries are associated with the wearing of seat belts and if the presence of cutaneous seat belt markings observed on victims of lethal vehicle crashes increased the likelihood of underlying injury. Autopsy reports from the files at Forensic Science South Australia were reviewed for all fatal motor vehicle crashes from January 2014 to December 2018. A total of 173 cases were included for analysis with 127 occupants wearing seat belts at the time of impact (73.4%) (age range = 18-93; mean = 45 M:F = 81:46). Of these, only 38 had external seat belt markings (29.9%) (age range = 19-83; mean = 49 M:F = 20:18). Logistic regression modelling showed that occupants who were wearing seat belts were more likely to experience closed head injury without skull fractures in addition to mesenteric and gastrointestinal injury. Increasing body mass index increased the incidence of seat belt markings (p < 0.01) and markings were more likely to be found in the presence of bilateral pelvic fractures. Thus, external seat belt markings were observed in only a minority of seatbelt wearers, and more often in individuals with higher BMIs and with bilateral pelvic fractures (possibly associated with greater momentum and impact force).

An overview of suicides related to motor vehicles

Although vehicles may be used in a wide variety of suicides, this has not been a focus in the forensic literature. Thus, an analysis of coronial autopsy reports at Forensic Science SA, Adelaide, South Australia over a 16-year period from January 2005 to December 2020 was undertaken to provide an overview of cases in which it was considered that a vehicle had been integral to the successful completion of a suicide. De-identified details were collected from all cases in which a vehicle had facilitated or been used as a method of suicide. A number of different types of vehicle-related suicide methods were identified, including cases where vehicles had been used as secure places for suicide or where the vehicle had been used to cause significant blunt force trauma or to enter a lethal environment such as water. Specific examples were taken from the following categories: (1) inhalation of gas, (2) drug toxicity, (3) hanging or ligature strangulation, (4) self-immolation, (5) drowning, (6) vehicle collision, (7) driving off a cliff, (8) jumping or lying in front of a vehicle and (9) the use of more than one method (i.e. complex). This report is not intended to provide an epidemiological analysis of car-related suicides. Instead, the details of selected cases have been used to illustrate the spectrum of methods that may be used in vehicle-assisted suicides.

Success of Low Aromatic Fuel in Preventing Gasoline Sniffing Deaths

ABSTRACT

Gasoline (petrol) sniffing is a form of volatile substance misuse that is particularly prevalent within Australian indigenous communities. Although epidemiological studies have shown that gasoline sniffing has decreased over recent years, rates of gasoline sniffing deaths have not been widely reported. Therefore, a study was undertaken to assess the association between the implementation of low aromatic fuel (LAF) and gasoline sniffing deaths. All cases of fatal gasoline sniffing in South Australia between 2000 and 2019 were identified from the Toxicology Database and autopsy reports at Forensic Science South Australia. Furthermore, previous studies of gasoline sniffing deaths were assessed to provide historical context and approximate rates of gasoline sniffing deaths before the current study. The rate of gasoline sniffing deaths decreased significantly ( P = 0.039) over the study period concomitant to an increase in the number of LAF sites nationally. Although not supported by findings of statistical significance because of the small number of cases, this study provides further supportive evidence for the effectiveness of LAF by showing a significant associated decrease in local rates of gasoline sniffing deaths.

Cardiac disease and driver fatality

To determine the role of cardiac disease in driver fatalities, a retrospective review of autopsy files at Forensic Science SA in Adelaide, Australia, was undertaken over a 13-year-period January 2005-December 2017 for individuals aged ≥ 40 years who had died while driving a motor vehicle. The incidence of significant coronary artery atherosclerosis (CAA) and cardiomegaly was evaluated with comparisons between drivers and a control group of passengers. Autopsy examinations were performed on 303 drivers and 72 passengers who died of trauma and on 63 drivers who died of a cardiac event while driving. The average age for drivers dying of trauma was 58.5 years (range 40-93 years) with 48 (15.8%) having CAA and 31 (10.2%) having cardiomegaly. This was not statistically different to passengers (aged 63.3 years; range 40-93 years; 20.8% having CAA; 11 (15.2%) cardiomegaly; (p > 0.2). Drivers with significant cardiac disease did not, therefore, have increased rates of death in crashes, although a distinct subgroup of drivers consisted of those who had died from cardiac events and not trauma, while driving. The latter may be increasing in number given the aging population.

Characteristics of fatal insulin overdoses

This study was undertaken to review fatal cases of insulin overdose in South Australia (SA) over a 20-year period to assess rates and characteristics of insulin-related deaths among insulin-dependent diabetics and non-diabetics for all manners of death. Records from the National Coronial Information System (NCIS) and Forensic Science SA (FSSA) were searched for all cases of fatal insulin overdose in South Australia (SA) between 2000 and 2019. Collected variables included age, sex, cause of death, scene findings, manner of death, decedent medical and personal histories, biochemistry, toxicology, histopathology, and autopsy findings. Statistical analyses were performed using R (version 4.1.2). Forty cases of insulin overdose were identified in SA between 2000 and 2019. Twenty-nine cases (72.5%) were suicides, with the remaining cases classified as accidental or undetermined intent. Thirteen of the 22 insulin-dependent diabetics (59%) had a history of depression, 10 of whom had previously demonstrated suicidal ideation. The current study has shown that suicides using insulin among insulin-dependent diabetics are equally as prevalent, if not more so than fatal accidental insulin overdoses. This can largely be attributed to insulin-dependent diabetic access to a potentially lethal substance. Suicide prevention strategies should focus on insulin-dependent diabetics with a history of depression, particularly for those with access to rapid-acting insulin.

Causes of fatalities in motor vehicle occupants: an overview

Injuries from motor vehicle collisions are frequently encountered in routine forensic practice. While the most common lethal events involve blunt force trauma with injuries to the head and neck, chest, abdomen, pelvis and limbs, review of the literature and case files shows that a wide variety of other fatal situations can occur that may involve sharp force and penetrating trauma, incineration, drowning, asphyxia, organic diseases and combinations of these. The following overview details potential factors that may contribute to death following vehicle crashes.

Methamphetamine use and the risk of diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a life-threatening condition arising in individuals with insulin-dependent diabetes mellitus, associated with hyperglycaemia and hyperketonaemia. While drugs such as methadone, cocaine and certain prescription medications may precipitate DKA, the potential effect of methamphetamine is unclear. Analysis of autopsy and toxicology case files at Forensic Science SA, Adelaide, South Australia, was therefore undertaken from 1 January to 31 December 2019 of all cases where methamphetamine was detected in post-mortem blood samples. There were 94 cases with 11 diabetics (n = 6 type 1 and n = 5 type 2). Four of the six decedents with type 1 diabetes had lethal DKA (66.7%; age range 30-54 years; average age 44.6 ± 10.5 years; M:F ratio 1:1). This incidence of DKA was higher than that of the general insulin-dependent diabetic population (6%) and also significantly higher than in medico-legal cases (13%; p < 0.05). The clinical and autopsy assessment of insulin-dependent diabetics presenting with DKA should therefore include specific screening for methamphetamine. The increase in both insulin-dependent diabetes and methamphetamine abuse in the community may lead to increases in such cases in medico-legal and health contexts.

Increasing use of sodium nitrite in suicides-an emerging trend

Sodium nitrite (NaNO₂) is a compound with broad practical applications in food preservation, automotive maintenance, and animal control. Sodium nitrite is also potentially fatal when ingested, as it interferes with the ability of red blood cells to transport oxygen. While incidents of accidental consumption have been reported in the literature, case reports of sodium nitrite being used as a pharmacological suicide agent are becoming more frequent. Therefore, a study was undertaken to evaluate trends in sodium nitrite deaths in South Australia between 2000 and 2019. All cases of fatal sodium nitrite ingestion were identified in the Toxicology database and autopsy reports at Forensic Science SA (FSSA). Ten cases of fatal sodium nitrite ingestion were identified, with the rate of cases increasing significantly over the study period (p > .001). Of the ten deaths attributed to sodium nitrite toxicity, eight were male, and two were female. The age range of decedents was 22-74 years (mean 51.9, SD 21.1), 22-74 years for males (mean 58.4, SD 18.2) and 23-29 years for females (mean 26.0, SD 4.2). Males (80%) and those with a history of depression and/or suicidal ideation (70%) were over-represented within the study population. While autopsy findings were generally consistent with the literature, scene findings emphasized the accessibility of sodium nitrite to the general public. This study highlights both a significant increasing trend in the use of sodium nitrite in suicides and important analytical limitations in the evaluation of suspected cases.

Methamphetamine and alcohol detection in vehicle-driver fatalities in South Australia: A 10-year survey (2008-2018)

Motor vehicle driver fatalities (≥18 years) from the files at Forensic Science South Australia were reviewed from January 2008 to December 2018 for cases in which either positive blood sample for methamphetamine (MA) or an illegal blood alcohol concentration (BAC) >0.05g/100 ml were found. Three hundred driver deaths were found with MA detected in 28 cases (age range 21-62 years; ave. 37.8 years; M:F 23:5). Hundred and fifteen cases with a BAC > 0.05 g/100 ml were identified (age range 18-67 years; ave 35.7 years; M:F 95:20). No change was found in numbers of MA cases, although alcohol cases showed a significant decline (p < 0.001). Drunk driving-related fatal crashes tended to occur in the evening (5 p.m. to 11 p.m.), while MA-related fatal crashes had a longer peak extending from late evening until late morning (11 p.m. to 8 a.m.). This study has demonstrated that while roadside breath testing, legislative changes, and increased monitoring have resulted in reduced levels of drunk driving, similar safety countermeasures have had negligible effects on MA use in drivers. Continued monitoring of MA use by drivers will, therefore, be necessary to assess the possible effects, or not, of new countermeasures.

Lethal mechanisms in cases of inverted suspension from the lap component of seat belts

A retrospective review of autopsy files at Forensic Science South Australia in Adelaide, Australia, was undertaken over a five-year period from January 2014 to December 2018 for all motor vehicle crashes with rollovers ending with the vehicle inverted and the occupants suspended by the lap component of their seat belts. There were five cases, all male drivers (aged 18-67 years; M_age = 32 years). Acute neck flexion or head wedging was noted in four cases, with facial petechiae in four and facial congestion in one. Deaths were due to positional asphyxia in four cases, with the combined effects of positional asphyxia and head trauma accounting for the remaining case. Although all drivers had evidence of head impact which may have caused incapacitation, in only one case was this considered severe enough to have contributed to death. A blood alcohol level above the legal limit for driving was detected in two cases, but no other drugs were detected. This series demonstrates another subset of cases of seat belt-associated deaths where suspension upside down by the lap component of a seat belt had occurred after vehicle rollovers. Predisposing factors include incapacitation of the victim and delay in rescue. The postulated lethal mechanism involved respiratory compromise from the weight of abdominal viscera on the diaphragm, as well as upper airway compromise due to kinking of the neck and wedging of the head.

Recent trends in barbiturate detection in medicolegal deaths

A study was undertaken of 51 cases where barbiturates were detected in post-mortem blood samples from 2000 to 2019 at Forensic Science South Australia, Adelaide, Australia. The cause of death was drug toxicity in only 27 (53%) (M:F = 19:8; age range 19-74yrs, mean 46yrs). In 17 cases, barbiturate toxicity was the primary cause of death, 14 due to pentobarbitone and 3 to phenobarbitone. All were suicides. Barbiturates were obtained by online purchase from overseas sources in 9 cases (33%), and through veterinary practice in 2 cases (7%). Drug toxicity deaths where barbiturates were detected rose from 1 in 2000-2004 to 11 in 2015-2019, and those where deaths were primarily due to barbiturate toxicity rose from 1 in 2000-2004 to 9 in 2015-2019. However, the mere detection of barbiturates in post mortem samples did not equate with illicit use, as 23 of the deaths (45%) were due to natural causes in individuals prescribed barbiturates for epilepsy. The usefulness of examining subset populations separate from accrued national data is also demonstrated in the significantly younger age of decedents in South Australia dying from deliberately administered barbiturates (46 yrs) compared to the national average of 57.9 yrs. The reasons for this difference will require further investigation as this may impact upon local suicide prevention strategies.

Increasing age and methamphetamine use

ANALYSIS

of autopsy files at Forensic Science SA was undertaken over a 20-year period (2000-2019) in five representative time periods to determine the average ages for all adults (≥18 years) where methamphetamine was detected. There were 239 cases with statistically significant increased mean ages over the time of the study ranging from 32.6yrs in 2000 to 42.2yrs in 2019 (p < 0.0001). Although methamphetamine use may be considered predominantly a feature of younger individuals this does not appear to be the case. Whether this apparent increase in the age of methamphetamine users was due to natural aging of methamphetamine users, an increase in use of methamphetamine by older individuals, or to an increased capture of older cases due to wider toxicological screening is uncertain. However, the importance of these results is to alert practitioners to the presence of methamphetamine use in older individuals which may predispose to death given the increased incidence of underlying cardiovascular diseases with age. In addition, in clinical settings there exists a cohort of older individuals who may be at risk of exacerbating their heart disease and precipitating cardiac events by using methamphetamine.

Characteristics of drowning deaths in an inner city river

A study was undertaken of all drowning deaths that occurred over a 30-year period from 1988 to 2017 in the urban section of the River Torrens, Adelaide, South Australia, an augmented waterway that runs through the central business district. Autopsy records from Forensic Science South Australia (FSSA) were reviewed. There were 34 drownings (0-5 cases/yr) with 28 males and 6 females (M;F = 4.6:1), with an age range for males of 18-76yrs (mean 42.0; SD 18.0) and for females of 20-84yrs (mean 69.3; SD 24.5). There were 15 (44%) accidents, 11 (32%) suicides, 1 (3%) homicide and 7 (21%) undetermined. Of the 22 cases during or after 1994 with complete toxicology reports, 10 (45%) had a blood alcohol concentration (BAC) of greater than 0.05% (g/100 mL) with an illicit substance detected in 4 (18%) cases: (MDMA (3,4-methylenedioxymethamphetamine), methylamphetamine and THC (delta-9-tetrahydrocannabinol) acid). The presence of various therapeutic drugs was also detected in 10 cases (45%) including temazepam, fluoxetine, diazepam, olanzapine, amitriptyline, carbamazepine, codeine, citalopram and valproate. Although the numbers of cases were not high, the urban portion of the River Torrens had a much higher number of drowning events per kilometre compared to other inland waterways in South Australia such as the Murray River. This is most likely due to the vulnerability that exists for intoxicated individuals in the city from falls into the water and to the availability of the river as a means of suicide to members of the adjacent urban population.

Childhood cycling fatalities in South Australia before and after the introduction of helmet legislation

In the years following the introduction of legislation in Australian states mandating the wearing of helmets, there was a decline in the number of deaths. Debate has occurred, however, as to why this occurred. The Traffic Accident Reporting System database, which records data for all police-reported crashes in South Australia, was searched for all cases of deaths occurring in the state in bicycle riders aged ≤14 years from January 1982 to December 2001. The numbers of deaths were then compared over the 10-year periods before (1982-1991) and after (1992-2001) the introduction of helmet legislation, and also on a yearly basis from 1982 to 2001. Comparing the numbers of deaths in the two periods before and after helmet legislation in 1991 showed a marked decrease in cases from 36 to 12. However, in examining the numbers of deaths per year in greater detail, it appears that these were already steadily reducing from nine cases per year in 1982 (2.9/100,000) to two cases in 1991 (0.67/100,000) to a virtual plateau after 1991 (ranging from 0 to 2 cases annually). It seems that the introduction of compulsory bicycle helmet wearing in South Australia came at a time when the numbers of child cyclist deaths had been steadily declining over the preceding decade. While helmet wearing clearly protects children who are still riding bicycles, the reasons for the reduction in numbers of deaths appears more complex than legislative change and likely involves a subtle interaction with other behavioural and societal factors and preferences.

Injuries, death and vehicle airbag deployment

Airbags are impact-activated safety devices which deploy from the interior of vehicles to protect occupants from trauma during crashes. Although airbags effectively reduce the risk of death and injury, this it is not without issues. For example, high-impact unbelted rigid-barrier testing in the USA led to the adoption of powerful, large airbags that were associated with numerous airbag-related deaths and injuries. In contrast, European designs were tested and certified in conjunction with the use of three-point restraint systems, meaning that the airbags could be smaller with reduced ‘punch-out’ power. An overview is provided of the mechanism of action of airbags and the associated non-lethal and lethal injuries that may be sustained by vehicle occupants.

Obesity and age as factors in leg amputations in fatal motorcycle crashes

The autopsy files at Forensic Science South Australia were searched over an 11-year period from January 2008 to December 2018 for all cases of motorcycle fatalities in which there had been lower-limb amputations. Six cases were identified, consisting of five male riders and one female pillion passenger. The age range was 48–67 years (average 59 years), which was significantly older than the control group (40.6 years; p < 0.01). All the decedents were overweight, with a body mass index (BMI) of 28.7–43.5 kg/m2 (average 34.9 kg/m2), which again was significantly greater than the control group (28.8 kg/m2; p < 0.05). Five of the incidents involved a collision between a motorcycle and a motor vehicle; the remaining case involved a collision with a tree. Five of the amputations were on the right side in the motorcycle-vehicle impacts, and they varied in severity from loss of a foot to a hind-quarter amputation. There was a single left lower-leg amputation which occurred during the collision with a tree, which was beside the road on the motorcyclist’s left. This study has shown that motorcyclists at greatest risk of lower-limb/pelvis amputations are older than the average rider with higher BMIs. This may be significant information given the increase in both BMI and age in many populations.

Increasing incidence of nonlethal inflicted injuries in paediatric homicides: A 45-year study

A retrospective study was undertaken at Forensic Science South Australia of all homicides in individuals aged <18 years from January 1970 to December 2014. 166 cases were identified (M:F = 1.5:1). The number of cases steadily declined, with the highest numbers and death rate occurring between 1970 and 1974 (N = 26; 0.37/100,000 population), and the lowest between 2010 and 2014 (N = 8; 0.1/100,000) (p < 0.01). Deaths were due to blunt force trauma (37%), gunshot wounds (19%), asphyxiation (18%), sharp force trauma (8%), poisoning (8%), burns (3%) and neglect (1%), or were undetermined (6%). There was a significant increase in numbers of accompanying nonfatal injuries (3.46 per case for 1970 and 1974, compared to 18.88 per case for 2010 and 2014). Thus, while both the absolute numbers and the rates of paediatric homicides declined significantly, numbers of nonlethal injuries increased. Whatever the underlying reason(s) for the increase in nonlethal injuries, fatal attacks on children in South Australia appear to be becoming more violent.

The use of therapeutic magnesium for neuroprotection during global cerebral ischemia associated with cardiac arrest and cardiac surgery in adults: a systematic review

BACKGROUND

Global cerebral ischemia occurs due to reduced blood supply to the brain. This is commonly caused by a cessation of myocardial activity associated with cardiac arrest and cardiac surgery. Survival is not the only important outcome because neurological dysfunction impacts on quality of life, reducing independent living. Magnesium has been identified as a potential neuroprotective agent; however, its role in this context is not yet clear.

OBJECTIVES

The objective of this review was to present the best currently available evidence related to the neuroprotective effects of magnesium during a period of global cerebral ischemia in adults with cardiac arrest or cardiac surgery.

INCLUSION CRITERIA TYPES OF PARTICIPANTS

The current review considered adults aged over 18 years who were at risk of global cerebral ischemia associated with cardiac arrest or cardiac surgery. Studies of patients with existing neurological deficits or under the age of 18 years were excluded from the review.

TYPES OF INTERVENTION(S)/PHENOMENA OF INTEREST

The intervention of interest was magnesium administered in doses of at least of 2 g compared to placebo to adult patients within 24 hours of cardiac arrest or cardiac surgery.

TYPES OF STUDIES

The current review considered experimental designs including randomized controlled trials, non-randomized controlled trials and quasi-experimental designs.

OUTCOMES

The outcome of interest were neurological recovery post-cardiac arrest or cardiac surgery, as measured by objective scales, such as but not limited to, cerebral performance category, brain stem reflexes, Glasgow Coma Score and independent living or dependent living status. To enable assessment of the available data, neuroprotection was examined by breaking down neurological outcomes into three domains - functional neurological outcomes, neurophysiological outcomes and neuropsychological outcomes.

SEARCH STRATEGY

The search strategy aimed to find both published and unpublished studies between January 1980 and August 2014, utilizing the Joanna Briggs Institute (JBI) three-step search strategy. Databases searched included PubMed, Embase, CINAHL, Cochrane Central Register of Controlled Trials, Australian Clinical Trials Register, Australian and New Zealand Clinical Trials Register, Clinical Trials, European Clinical Trials Register and ISRCTN Registry.

METHODOLOGICAL QUALITY

The studies included in this review were of moderate-to-good-quality randomized controlled trials. Studies included measured neurological outcome using functional neurological assessment, neuropsychiatric assessment or neurophysiological assessment.

DATA EXTRACTION

Data were extracted using standardized templates provided by the JBI Meta-analysis of Statistics Assessment and Review Instrument software.

DATA SYNTHESIS

Quantitative data were, where possible, pooled in statistical meta-analysis using Review Manager 5.3 (The Nordic Cochrane Centre, Cochrane; Copenhagen, Denmark). Where statistical pooling was not possible, the findings were presented in narrative form, including tables and figures, to aid in data presentation, where appropriate.

RESULTS

Seven studies with a total of 1164 participants were included in this review. Neurological outcome was categorized into three domains: functional neurological, neurophysiological and neuropsychological outcomes. Meta-analysis of three studies assessing the neuroprotective properties of magnesium administration post cardiac arrest found improved functional neurological outcome (odds ratio 0.44; 95% confidence interval 0.24-0.81).

CONCLUSION

Magnesium may improve functional neurological outcome in patients who suffer global cerebral ischemia associated with cardiac surgery and cardiac arrest. Magnesium does not decrease neuropsychological decline.Further testing of neurological outcomes in the domains of functional outcomes, neurophysiological markers and neuropsychological tests are required to further understanding of the neuroprotective effects of magnesium. Suitable dosing regimens should be investigated prior to introduction into clinical practice. Further research is required to investigate the optimal magnesium dose.

Prison suicides in South Australia: 1996-2010

Forty-eight deaths occurring in prisons in South Australia were identified between January 1996 and December 2010, including 25 cases of suicide (mean age = 37 years; median age = 34 years; age range = 24-70 years). Most suicides were due to hanging (23/25; 92.0%) with victims using bedding, belts, or shoelaces attached to cell shelves, air vents, doors, or other accessible projections. There were no suicides attributed to drug overdose or sharp force injury. Over a third of all suicides (39.1%) occurred during the first month of confinement, with 26.1% of cases occurring within the first week. There was one suicide reported after 2 years of imprisonment. Given that suicide in state prisons currently occurs at a rate approximately eight times that of the general South Australian community, it appears that the subset of incarcerated individuals represents a group in need of effective preventive strategies to enable more appropriate provisions of existing prisoner resources.

Cushing's mechanism maintains cerebral perfusion pressure in experimental subarachnoid haemorrhage

Mortality following subarachnoid haemorrhage (SAH) is high, especially within the first 48 h. Poor outcome is predicted by high intracranial pressure which causes diminished cerebral perfusion pressure unless a compensatory increase in mean arterial blood pressure occurs. Therefore blood pressure elevation can be protective following subarachnoid haemorrhage despite the potential for rebleeding. This study investigated blood pressure responses to SAH and the impact on cerebral perfusion pressure and outcome, as demonstrated by two experimental models. Various blood pressure responses were demonstrated, both at the ictus and within the following 5h. Elevated MABP at the ictus and at 2h following experimental SAH was associated with maintenance of CPP in the presence of raised ICP. Poor outcome (arrest of the cerebral circulation) was predicted by failure of MABP to increase significantly above sham levels within 2h of SAH. Rat SAH provides relatively inexpensive models to investigate physiological mechanisms that maintain cerebral perfusion in the presence of intracranial hypertension.

Physician suicide

Pathology files at Forensic Science South Australia were examined over a 14-year period, from January 1997 to March 2011 for cases of physician suicide. Nine cases were identified (ages, 30-69 years; median = 41 years; M:F = 3:1). Three cases (33.3%) had a history of prescription drug abuse, and eight cases (88.9%) died from lethal drug self-administration. Intravenous administration of drugs was the favored method in seven cases. In only one case was an alternative method used, involving jumping from a high building. A history of depression and/or suicidal ideation was noted in six cases (66.7%). The methods of self-destruction contrasted with the general population where hanging, carbon monoxide poisoning, and gunshot wounds are more common. Availability and knowledge of lethal effects have been shown to be important determinants in the choice of methods of suicide. Access to drugs should therefore be carefully monitored in physicians with histories of depression and/or substance abuse.

sAPPα rescues deficits in amyloid precursor protein knockout mice following focal traumatic brain injury

The amyloid precursor protein (APP) is thought to be neuroprotective following traumatic brain injury (TBI), although definitive evidence at moderate to severe levels of injury is lacking. In the current study, we investigated histological and functional outcomes in APP-/- mice compared with APP+/+ mice following a moderate focal injury, and whether administration of sAPPα restored the outcomes in knockout animals back to the wildtype state. Following moderate controlled cortical impact injury, APP-/- mice demonstrated greater impairment in motor and cognitive outcome as determined by the ledged beam and Barnes Maze tests respectively (p < 0.05). This corresponded with the degree of neuronal damage, with APP-/- mice having significantly greater lesion volume (25.0 ± 1.6 vs. 20.3 ± 1.6%, p < 0.01) and hippocampal damage, with less remaining CA neurons (839 ± 245 vs. 1353 ± 142 and 1401 ± 263). This was also associated with an impaired neuroreparative response, with decreased GAP-43 immunoreactivity within the cortex around the lesion edge compared with APP+/+ mice. The deficits observed in the APP-/- mice related to a lack of sAPPα, as treatment with exogenously added sAPPα post-injury improved APP-/- mice histological and functional outcome to the point that they were no longer significantly different to APP+/+ mice (p < 0.05). This study shows that endogenous APP is potentially protective at moderate levels of TBI, and that this neuroprotective activity is related to the presence of sAPPα. Importantly, it indicates that the mechanism of action of exogenously added sAPPα is independent of the presence of endogenous APP.

Recent firing range suicides in South Australia

Two cases are reported from South Australia, where deaths occurred that were due to single self-inflicted gunshot wounds to the head in individuals who were visiting indoor firearm ranges. Case 1: A 54-year-old man visiting an indoor firing range placed a .357 magnum handgun to his head and fired one shot. Case 2: A 23-year-old woman who was being instructed in firearm usage at an indoor firing range placed a 9 mm handgun to her head and fired one shot. In both cases, deaths were due to cerebral laceration with skull fracture. Firing ranges may be utilized by individuals who are seeking weapons for suicide attempts, and suicide may be successfully undertaken at such locations even while a victim is under direct supervision. In jurisdictions, where firearm ownership is strictly legislated, it may be that clubs can inadvertently provide access to firearms for this type of activity.

Characterisation of the effect of knockout of the amyloid precursor protein on outcome following mild traumatic brain injury

The amyloid precursor protein (APP) increases following traumatic brain injury (TBI), although the functional significance of this remains unclear largely because the functions of the subsequent APP metabolites are so different: Aβ is neurotoxic whilst sAPPα is neuroprotective. To investigate this further, APP wildtype and knockout mice were subjected to mild diffuse TBI and their outcomes compared. APP knockout mice displayed significantly worse cognitive and motor deficits, as demonstrated by the Barnes Maze and rotarod respectively, than APP wildtype mice. This was associated with a significant increase in hippocampal and cortical cell loss, as well as axonal injury, in APP knockout mice and an impaired neuroreparative response as indicated by diminished GAP-43 immunoreactivity when compared to APP wildtype mice. This study is the first to demonstrate that endogenous APP is beneficial following mild TBI, suggesting that the upregulation of APP observed following injury is an acute protective response.

Transient receptor potential melastatin 2 expression is increased following experimental traumatic brain injury in rats

Traumatic brain injury (TBI) elicits a sequence of complex biochemical changes including oxidative stress, oedema, inflammation and excitotoxicity. These factors contribute to the high morbidity and mortality following TBI, although their underlying molecular mechanisms remain poorly understood. Transient receptor potential melastatin 2 (TRPM2) is a non-selective cation channel, highly expressed in the brain and immune cells. Recent studies have implicated TRPM2 channels in processes involving oxidative stress, inflammation and cell death. However, no studies have investigated the role of TRPM2 in TBI pathophysiology. In the present study, we have characterised TRPM2 mRNA and protein expression following experimental TBI. Adult male Sprague Dawley rats were injured using the impact-acceleration model of diffuse TBI with survival times between 5 and 5 days. Real-time RT-PCR (including reference gene validation studies) and semi-quantitative immunohistochemistry were used to quantify TRPM2 mRNA and protein levels, respectively, following TBI. Significant increases in TRPM2 mRNA and protein expression were observed in the cerebral cortex and hippocampus of injured animals, suggesting that TRPM2 may contribute to TBI injury processes such as oxidative stress, inflammation and neuronal death. Further characterisation of how TRPM2 may contribute to TBI pathophysiology is warranted.

Reference genes for normalising gene expression data in collagenase-induced rat intracerebral haemorrhage

Background

The mechanisms of brain injury following intracerebral haemorrhage (ICH) are incompletely understood. Gene expression studies using quantitative real-time RT-PCR following ICH have increased our understanding of these mechanisms, however the inconsistent results observed may be related to inappropriate reference gene selection. Reference genes should be stably expressed across different experimental conditions, however, transcript levels of common reference genes have been shown to vary considerably. Reference gene panels have therefore been proposed to overcome this potential confounder.

Results

The present study evaluated the stability of seven candidate reference genes in the striatum and overlying cortex of collagenase-induced ICH in rodents at survival times of 5 and 24 hours. Transcript levels of the candidate reference genes were quantified and ranked in order of stability using geNorm. When our gene of interest, transient receptor potential melastatin 2 (TRPM2), was normalised against each reference gene individually, TRPM2 mRNA levels were highly variable. When normalised to the four most stable reference genes selected for accurate normalisation of data, we found no significant difference between ICH and vehicle rats.

Conclusion

The panel of reference genes identified in the present study will enable more accurate normalisation of gene expression data in the acute phase of experimental ICH.

Substance P antagonists as a therapeutic approach to improving outcome following traumatic brain injury

Although a number of secondary injury factors are known to contribute to the development of morphological injury and functional deficits following traumatic brain injury, accumulating evidence has suggested that neuropeptides, and in particular substance P, may play a critical role. Substance P is released early following acute injury to the CNS as part of a neurogenic inflammatory response. In so doing, it facilitates an increase in the permeability of the blood-brain barrier and the development of vasogenic edema. At the cellular level, substance P has been shown to directly result in neuronal cell death; functionally, substance P has been implicated in learning and memory, mood and anxiety, stress mechanisms, emotion-processing, migraine, emesis, pain, and seizures, all of which may be adversely affected after brain injury. Inhibition of post-traumatic substance P activity, either by preventing release or by antagonism of the neurokinin-1 receptor, has consistently resulted in a profound decrease in development of edema and marked improvements in functional outcome. This review summarizes the current evidence supporting a role for substance P in acute brain injury.

Magnesium in acute and chronic brain injury: an update

While brain free magnesium levels have been shown to decline in a number of acute and chronic brain pathologies, the mechanisms of such decline and the potential for magnesium administration as a therapeutic intervention are still unclear. In acute brain injury, magnesium therapy has failed in recent clinical trials of trauma, presumably because of an intact blood brain barrier at the time of administration reducing central penetration. Under such conditions, magnesium's peripheral effects on cardiovascular parameters may dominate over the central, and potentially neuroprotective, effects of the compound. In contrast, magnesium has been demonstrated to be beneficial in lacunar strokes, albeit that recent animal studies indicate that this effect is without any significant reduction of lesion size. Postnatal magnesium has also been shown to improve neurological outcome in term neonates with perinatal asphyxia, although this may be limited to cases of mild to moderate brain injury; no effect is observed following severe brain injury. Prenatal magnesium has been reported to be beneficial for outcome in very preterm infants, although this may only be at low doses. Combination therapies are also showing promise in experimental studies, with combined magnesium and mild hypothermia as well as magnesium and polyethylene glycol proving effective in ischemic stroke and in spinal cord injury, respectively. With respect to chronic brain injury, recent results indicate that magnesium deficient mice are susceptible to developing Parkinson's disease, which is consistent with earlier findings that magnesium deficiency over a number of generations is associated with the development of Parkinson's disease. The latter was associated with the appearance of variants of the TRPM channels. Our recent studies have shown that Parkinson's disease is associated with reduced TRPM2 and TRPM7 channel mRNA expression. Taken together, a more complete picture is emerging of the role of magnesium in brain injury, its therapeutic potential as well the mechanisms associated with its decline.

Magnesium gluconate offers no more protection than magnesium sulphate following diffuse traumatic brain injury in rats

OBJECTIVE

Previous studies have demonstrated that magnesium salts, including the sulphate and chloride forms, are neuroprotective following traumatic brain injury (TBI). Recently, studies in cardiac ischaemia/reperfusion injury have demonstrated that the gluconate salt of magnesium may provide superior protection against oxidative damage and postischaemic dysfunction than MgSO(4). We have therefore compared the efficacy of both MgSO(4) and magnesium gluconate (MgGl(2)) on outcome following diffuse TBI in rats.

METHODS

Adult male Sprague-Dawley rats were injured using the 2-metre impact acceleration model of diffuse TBI. At 30 min after injury, animals were administered with either 250 micromoles/kg i.v. MgSO(4), MgGl(2), or equal volume saline vehicle. Thereafter, animals were assessed for motor and cognitive outcome using the rotarod and Barnes maze, respectively, or their brains removed at 3 days after TBI and used for histological examination.

RESULTS

Treatment with either magnesium salt significantly improved functional outcome as compared to vehicle treated controls. Similarly, treatment with either magnesium salt attenuated the degree of histological dark cell change at 3 days after TBI relative to the vehicle treated animals. There were no significant differences between the magnesium treated groups.

CONCLUSIONS

We conclude that MgSO(4) and MgGl(2) are equally neuroprotective following TBI. Our results suggest that MgGl(2) may only be more effective in conditions that produce ischaemia, where high concentrations of reactive oxygen species are generated.

The role of magnesium in traumatic brain injury

In Japan, over 5,000 deaths per year are a result of traumatic brain injury (TBI) with most being due to motor vehicle accidents. Survivors of TBI number into the hundreds of thousands and are often left with debilitating neurological deficits. Recently it has been identified that much of the brain damage after TBI develops over time with the primary injury initiating a secondary injury cascade made up of deleterious pathophysiological and biochemical reactions. The delayed development of secondary injury creates an opportunity for therapeutic intervention and considerable effort is being directed toward identifying the secondary injury factors and developing interventions that may potentially prevent their actions. Several secondary injury factors have been identified including oxidative stress, changes in blood flow, neurotransmitters and ionic changes, oedema and energy failure. Of these, Mg(2+) decline has been identified as playing a crucial role in the secondary injury process, in part because of its central role in the regulation of a large number of other known injury factors. This brief review will summarize the experimental evidence supporting a critical role of Mg(2+) in the pathophysiology of TBI, and will examine the use of magnesium salts as a therapeutic intervention.