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Biomedical subjects

J G Young

Publications and source records attributed to J G Young.

At least 19 recordsLinked to original sources
PubMed2005

A study of the personal radiation dose received by nuclear medicine technologists working in a dedicated PET center.

The use of dedicated PET scanners is becoming more widespread throughout Australia and the world. PET imaging utilizes short-lived (approximately 108 min), high-energy (511 keV) gamma-ray emitters that could result in a high radiation dose being received by staff. As part of a larger staff and area monitoring project, this paper discusses the personal dose equivalent, H(p)(10), received by PET staff working in a dedicated PET center. The typical H(p)(10) received by staff was approximately 1 microSv per minute of close contact with patients, which resulted in an average daily dose for nuclear medicine technologists of approximately 31 microSv. The average daily administered activity to patients at Austin Health was 1,280 MBq.

Humans↗
PubMed1999

Mechanisms of aortic injury in fatalities occurring in motor vehicle collisions.

Case reviews based on autopsy studies have shown that motor vehicle collisions cause between 50 and 90% of traumatic aortic ruptures. Very few studies have analyzed the nature and severity of the collision forces associated with this injury. Our passenger car study (1984-1991) examined 36 collisions in which 39 fatally injured victims sustained aortic trauma. In this injury group, a disproportionate number of heavy truck and roadside fixed-object impacts occurred. Vehicle crash forces were generally severe and were either perpendicular or oblique to the vehicle surface. Intrusion into the occupant compartment was a significant factor in most of these fatal injuries. Occupant contact with vehicle interior surfaces was identified in most cases, and occupant restraints were often ineffective, especially in side collisions. The more elderly victims were seen in the least severe collisions. The most frequent site of aortic rupture was at the isthmus. A majority of victims had rib/sternal fractures indicating significant chest compression. Of the various traumatic aortic injury mechanisms proposed in motor vehicle impacts, the favored theories in the literature combine features of rapid deceleration and chest compression. This study supports that predominant impression, concluding that rapid chest deceleration/compression induces torsional and shearing forces that result in transverse laceration and rupture of the aorta, most commonly in the inherently vulnerable isthmus region.

Accidents, Traffic↗
PubMed1998

Unexpected death related to restraint for excited delirium: a retrospective study of deaths in police custody and in the community.

BACKGROUND: Some people in states of excited delirium die while in police custody. Emerging evidence suggests that physical restraint in certain positions may contribute to such deaths. In this study the authors determined the frequency of physical restraint among people in a state of excited delirium who died unexpectedly. METHODS: The authors reviewed the records of 21 cases of unexpected death in people with excited delirium, which were investigated by the Office of the Chief Coroner for Ontario between 1988 and 1995. Eyewitness testimony, findings during postmortem examinations, clinical history, toxicological data and other official documents describing the events surrounding the deaths were analyzed. Specific reference was made to documented eyewitness testimony of restraint method, body position and use of capsicum oleoresin (pepper) spray. Because cocaine was detected in the blood of some of these people during the postmortem examination, the role of cocaine in excited delirium was examined by comparing the cocaine levels in these cases with levels in 2 control groups: 19 people who died from acute cocaine intoxication and 21 people who had used cocaine shortly before they died but who had died from other causes. RESULTS: In all 21 cases of unexpected death associated with excited delirium, the deaths were associated with restraint (for violent agitation and hyperactivity), with the person either in a prone position (18 people [86%]) or subjected to pressure on the neck (3 [14%]). All of those who died had suddenly lapsed into tranquillity shortly after being restrained. The excited delirium was caused by a psychiatric disorder in 12 people (57%) and by cocaine-induced psychosis in 8 (38%). Eighteen people (86%) were in police custody when they died. Four (19%) had been sprayed with capsicum oleoresin, and heart disease was found in another 4 at autopsy. The blood level of cocaine in those whose excited delirium was cocaine induced was similar to levels found in recreational cocaine users and lower than levels found in people who died from cocaine intoxication. INTERPRETATION: Restraint may contribute to the death of people in states of excited delirium, and further studies to test this hypothesis are recommended. Meanwhile, law enforcement authorities and others should bear in mind the potential for the unexpected death of people in states of excited delirium who are restrained in the prone position or with a neck hold.

Adolescent↗
PubMed1996

Sudden unexplained death in Asian immigrants: recognition of a syndrome in metropolitan Toronto.

OBJECTIVE: To determine the number of Southeast Asians in Ontario who died of the sudden unexplained death syndrome in Asian immigrants. DESIGN: Retrospective review. SETTING: Ontario. CASES: All deaths reported to the Office of the Chief Coroner for Ontario from 1992 to 1995. OUTCOME MEASURES: Age, residence and country of origin of people who died of sudden unexplained death syndrome in Asian immigrants, as defined by standard criteria, autopsy findings and social history of cases. RESULTS: Eight cases of sudden unexplained death in Asian immigrants were reported during the study period. All involved men, and the mean age at death was 34 (standard error of the mean 7) years (range 23 to 44 years). All of the people were residents of metropolitan Toronto. Four were from Vietnam, three from China and one from the Philippines. Seven people lived with family members; the eighth was unemployed and lived alone. Death occurred during sleep or in the waking hours of the morning in six cases; in two of these cases the person's spouse was awakened by loud, laboured breathing. Two men experienced chest pain, and one of them also had sudden-onset dyspnea. There was no prodromal illness in any case. The only consistent autopsy finding was acute nonspecific pulmonary edema and congestion. Analysis of heart weights failed to reveal signs of significant cardiomegaly. CONCLUSION: Men from Southeast Asia aged 20 to 45 years are at risk of sudden unexplained death, which usually occurs during sleep. No specific factors have been found that could be used to identify people at risk.

Adult↗
PubMed1996

Commercial logging fatalities in Ontario, 1986-1991.

Despite the economic importance and hazardous nature of commercial logging in various regions, few medical studies have examined fatalities in this industry. Data derived from the files of the Ontario Chief Coroner's Office revealed 52 deaths, all men, from 1986 to 1991 in the province of Ontario. Forty-four cases were accidents (age range 20-73 years; average, 44 years), the majority involving experienced loggers. Personal error resulting in preventable unsafe work practices was a factor in most accidents (n = 35; 79.5%). Almost one half of injured workers were struck by either dead or cut trees. Although the majority of cases occurred in remote areas, delayed medical attention as a factor contributing to death was uncommon. Many of the injuries were nonsurvivable and most victims (n = 33; 75%) were dead at the scene. Most deaths were caused by either head and neck injuries (n = 20; 45.5%), multiple trauma (n = 10; 23%), chest trauma only (n = 6; 13.5%), or mechanical asphyxia (n = 5; 11%). Blood alcohol was negative in 24 accident victims tested. Eight deaths (age range 42-52 years; average, 49 years) were due to cardiac causes, mainly ischemic heart disease. Disease may have contributed to two accidents.

Abdominal Injuries↗
PubMed1996

Fatal light aircraft accidents in Ontario: a five year study.

Fatal civil aviation crashes in Ontario from 1985 to 1989 were studied. Data regarding accident circumstances, injury patterns and medical factors (disease, alcohol/drugs) which could have contributed to accident causation was obtained from a review of the files of the Chief Coroner for Ontario in Toronto and the aviation occurrence reports of the Transportation Safety Board of Canada. Forty-seven crashes involving mainly general aviation type aircraft but also 2 gyroplanes, 2 ultralights and a glider were reviewed. About half occurred during the cruise phase of the flight. Seventy (40 pilots; 30 passengers) of the 98 occupants died. The bodies of 68 victims were recovered; 63 were dead at the scene and 5 survived up to ten hours after impact. Multiple trauma killed about half of all the victims (n = 34); 29% (n = 20) drowned; 16% (n = 11) and 3% (n = 2) died of head/neck injuries and coronary disease respectively. Neck trauma was observed mostly in pilots and was the most frequent major blunt trauma injury in drowning victims. Passengers sustained relatively more craniofacial fractures and abdominal/retroperitoneal trauma. Pilot error was the most frequent cause of crashes (55%; 26/47 impacts) followed by mechanical failure (15%; 7/47) and adverse weather/environmental conditions (11%; 5/47). Coronary artery disease incapacitated two pilots (4% of crashes) and ethanol intoxication was implicated in two other accidents. Other drugs did not appear to be a definite factor in accident causation.

Accidents, Aviation↗
PubMed1994

Clomipramine ameliorates adventitious movements and compulsions in prepubertal boys with autistic disorder and severe mental retardation.

In an open, nonblind clinical trial, clomipramine reduced adventitious movements and compulsions in five previously medicated prepubertal boys with autistic disorder and severe mental retardation. Poorly adapted rating scales, interrater variability, subject heterogeneity, different treatment histories, and environmental stresses confounded the assessment of treatment effects.

Autistic Disorder↗
PubMed1994

Speaking for the dead to protect the living: the role of the coroner in Ontario.

This paper describes the historical origins, modern-day operations and complexities of the Ontario coroners system. Both the Office of the Chief Coroner and Statistics Canada publish death statistics for the province of Ontario. The time required by the coroner's office to produce accurate cause-of-death data may significantly exceed the time constraints faced by Statistics Canada in producing its own annual cause-of-death statistics. As a result, substantial discrepancies arise in the number of deaths attributed to accidents, suicides and homicides that are published by these two agencies.

Cause of Death↗
PubMed1994

Comparison of thermoluminescence and electron spin resonance as dosimetry methods in the investigation of the dose distribution inside a 137Cs Gammacell-1000 irradiator.

Thermoluminescence dosimetry (TLD) using LiF:Mg,Ti and electron spin resonance dosimetry using alanine (ALD) have been used to map the dose distribution in the sample chamber of a Gammacell-1000 Irradiator. The results showed that the dose rate to air varied by approximately 20% over the volume of the chamber. The mean ratio of the dose rates at various locations throughout the chamber, TLD/ALD was 1.020 +/- 0.025 (1 sd). The dose range around 30 Gy is regarded as being towards the upper limit of reliability for TLD measurements and towards the lower limit for ALD measurements.

Adsorption↗
PubMed1990

Growth hormone and prolactin response to methylphenidate in children with attention deficit disorder.

Utilizing a double-blind, drug-placebo design, we examined growth hormone (GH) and prolactin (Pro) response to oral administration of methylphenidate (MPH) in 14 boys (ages 7.0-12.4 years) with Attention Deficit Disorder (ADD). Four conditions representing three different MPH doses (0.3 mg/kg O.D., 0.3 mg/kg B.I.D., 0.6 mg/kg O.D.) and Placebo were compared in each subject, each condition lasting for a period of 3 weeks. GH and Pro response were measured both as maximum peak GH (DGH) or nadir of Pro (DPro) as well as area under the curve for the first four hours after MPH administration (AUCGH, AUCPro). Behavioral measures included parent ratings on the Yale Children's Inventory and teacher ratings on the Yale and Conners Behavior Rating Scales and Kagan's Matching Familiar Figures Test (MFFT). Prolactin response as measured by AUCPro was significantly increased after MPH compared to placebo (t = 2.04, p less than 0.05, placebo vs all doses MPH). This difference observed for AUCPro between placebo and MPH was evident as well when we considered the number of times AUCPro declined after MPH as compared to placebo (p = .018, Fisher's exact test). Within-subjects analysis of covariance demonstrated significant correlations between the improvement in reaction time on the MFFT and 1) GH response (AUCGH, r = .58, p less than .001) and 2) prolactin response (AUCPro, r = .40, p less than .05) and between improvement in attention as measured on the Yale BRS and GH response (AUCGH, r = .57, p less than .05). Our findings suggest that measures other than GH and prolactin may be more desirable measures of brain catecholaminergic functioning.

Attention Deficit Disorder with Hyperactivity↗
PubMed1990

Validation of hyperactive, aggressive, and mixed hyperactive/aggressive childhood disorders: a research note.

Eighty-five non-referred school children were divided into four groups based upon the IOWA Conners Teacher's Questionnaire: pure hyperactive (HYP), pure aggressive (AGG), mixed hyperactive/aggressive (HYP/AGG), and normal controls. The groups were compared on neurobehavioral tests believed to assess inattention and impulsivity. A continuous performance test indicated that the HYP group was more inattentive than the other groups and the HYP/AGG group was most impulsive. The AGG group did not differ from controls. The data support the distinction between HYP, AGG and HYP/AGG groups of children selected by the IOWA Conners.

Aggression↗
PubMed1990

Guns and suicide: possible effects of some specific legislation.

The authors describe suicide rates in Toronto and Ontario and methods used for suicide in Toronto for 5 years before and after enactment of Canadian gun control legislation in 1978. They also present data from San Diego, Calif., where state laws attempt to limit access to guns by certain psychiatric patients. Both sets of data indicate that gun control legislation may have led to decreased use of guns by suicidal men, but the difference was apparently offset by an increase in suicide by leaping. In the case of men using guns for suicide, these data support a hypothesis of substitution of suicide method.

Adult↗
PubMed1989

Preventable pediatric trauma deaths in a metropolitan region.

All pediatric trauma deaths occurring in metropolitan Toronto (population, 2.2 million) in 1986 were analyzed from the regional coroner's records. Injuries sustained were scored using the Abbreviated Injury Scale (1985; AIS) and Injury Severity Score (ISS). Victims with injuries graded AIS 6 (any region), AIS 5 head/neck (excluding acute epidural hematoma), or ISS greater than 59 were deemed unsalvageable. All other injuries were considered survivable and the deaths from them preventable. Use of these objective criteria indicated that 8/38 of the children (21%) who died from trauma had survivable injuries. Since in three cases medical aid was not sought because of social circumstances, 5/38 (13%) was considered a realistic estimate of preventable death rate (PDR). These results suggest that when objective criteria are used, the PDR in pediatric trauma may be less than that reported in adult trauma victims. Defining the PDR on the basis of objective criteria may prove useful in the conduct of further studies of this kind and permit valid comparisons to be made.

Adolescent↗
PubMed1989

Are ADDH and ADHD the same or different?

To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.

Attention↗