Faculty Bibliography

SUMMARY: Maize seedling transcriptome responses to six abiotic perturbations (heat, cold, darkness, desiccation, salt, ultraviolet-B) were analysed. Approximately 7800 transcripts were expressed in one or more treatments compared with light-grown seedlings plus juvenile leaves from field-grown plants. Approximately 5200 transcripts were expressed in one or more treatments and absent in light-grown seedlings. Approximately 2000 transcripts were unique to one treatment. Salt and heat elicited the largest number of transcript changes; however, salt resulted in mostly a decreased abundance of transcripts, whereas heat shock resulted in mostly an increased abundance of transcripts. A total of 384 transcripts were common to all stress treatments and not expressed in light-grown seedlings; 146 transcripts were present in light-grown seedlings and absent from all stress treatments. A complex pattern of overlapping transcripts between treatments was found, and a significant pattern of congruence in the direction of transcript change between pairs of treatments was uncovered. From the analysis, it appears that the scope of gene expression changes is determined by the challenge, indicating specificity in perception and response. Nonetheless, transcripts regulated by multiple responses are generally affected in the same manner, indicating common or converging regulatory networks. The data are available for additional analysis through a searchable database

Our purpose is to highlight novel ocular findings of 102 forensic pediatric cases under 2 years of age who die suddenly. Forensic information, grossing, and microscopic eye protocol was followed. The most common diagnosis was Sudden Infant Death Syndrome (SIDS) (57/102). Novel cytoid bodies were present in the retina of 72/102 cases and they were located predominantly 90% (65/72) at the anterior part of the retina (p < 0.001). Of the SIDS cases, 85% (47/57) showed the presence of cytoid bodies, and among all diagnosis, SIDS was the most associated with cytoid bodies (p = 0.003). A second observation was extramedullary hematopoiesis (EMH) identified in 35/102 cases and 22 of the 57 SIDS cases. The most frequent EMH location was the choroids (29/35). This study is the first to demonstrate the presence of cytoid bodies and extramedullary hematopoiesis in the retinas of SIDS cases and children who die suddenly from other causes

This retrospective study examined population demographics associated with motor vehicle collision (MVC) fatalities over a 5-year period in the Hamilton-Wentworth Niagara region. Variables were drawn from the five factors proposed by Fierro (1) for investigating deaths caused by transportation: human, chemical, environmental, vehicular, and highway. Factors analyzed included age, gender, position to the vehicle, site(s) of injury, toxicology, environmental contributors, and vehicular findings. From 1999 to 2004, there were 321 MVC fatalities that primarily involved males 20 to 29 years of age and commonly drivers or pedestrians. Cars and trucks were the most frequent vehicles. Fatalities occurred most often on local and regional roads on Fridays and Sundays between 6 pm and 6 am. Mechanical failure and weather conditions were not significant contributors. Toxicological analyses (275/321) were performed on the majority of the study population. Ethanol was present in isolation and with other substances, especially cannabis, mostly in male drivers 20-59 years of age

BACKGROUND: During flowering, central anther cells switch from mitosis to meiosis, ultimately forming pollen containing haploid sperm. Four rings of surrounding somatic cells differentiate to support first meiosis and later pollen dispersal. Synchronous development of many anthers per tassel and within each anther facilitates dissection of carefully staged maize anthers for transcriptome profiling. RESULTS: Global gene expression profiles of 7 stages representing 29 days of anther development are analyzed using a 44 K oligonucleotide array querying approximately 80% of maize protein-coding genes. Mature haploid pollen containing just two cell types expresses 10,000 transcripts. Anthers contain 5 major cell types and express >24,000 transcript types: each anther stage expresses approximately 10,000 constitutive and approximately 10,000 or more transcripts restricted to one or a few stages. The lowest complexity is present during meiosis. Large suites of stage-specific and co-expressed genes are identified through Gene Ontology and clustering analyses as functional classes for pre-meiotic, meiotic, and post-meiotic anther development. MADS box and zinc finger transcription factors with constitutive and stage-limited expression are identified. CONCLUSIONS: We propose that the extensive gene expression of anther cells and pollen represents the key test of maize genome fitness, permitting strong selection against deleterious alleles in diploid anthers and haploid pollen. Because flowering plants show a substantial bias for male-sterile compared to female-sterile mutations, we propose that this fitness test is general. Because both somatic and germinal cells are transcriptionally quiescent during meiosis, we hypothesize that successful completion of meiosis is required to trigger maturation of anther somatic cells

Selective serotonin reuptake inhibitors were introduced in 1987 as an alternative treatment option for patients with depression or certain anxiety disorders. Unfortunately, this greater use has prompted a corresponding increase in reports of more severe side effects and fatalities, with a majority of fatalities occurring due to coingestion of selective serotonin reuptake inhibitors with other substances or serotonergic drugs. We report a case which exemplifies one such fatality related to sertraline, lorazepam, and codeine coingestion. A brief discussion of the presumed mechanism by which death occurred will be offered

Oligonucleotide arrays were used to profile gene expression in dissected maize anthers at four stages: after-anther initiation, at the rapid mitotic proliferation stage, pre-meiosis, and meiotic prophase I. Nearly 9200 sense and antisense transcripts were detected, with the most diverse transcriptome present at the pre-meiotic stage. Three male-sterile mutants lacking a range of normal cell types resulting from a temporal progression of anther failure were compared with fertile siblings at equivalent stages by transcription profiles. The msca1 mutant has the earliest visible phenotype, develops none of the normal anther cell types and exhibits the largest deviation from fertile siblings. The mac1 mutant has an excess of archesporial derivative cells and lacks a tapetum and middle layer, resulting in moderate transcriptional deviations. The ms23 mutant lacks a differentiated tapetum and shows the fewest differences from fertile anthers. By combining the data sets from the comparisons between individual sterile and fertile anthers, candidate genes predicted to play important roles during maize anther development were assigned to stages and to likely cell types. Comparative analyses with a data set of anther-specific genes from rice highlight remarkable quantitative similarities in gene expression between these two grasses

Natural gas (NG) is used as a home energy supply and, with or without ignition, is rarely misused to result in death. The authors report an unusual suicidal explosive death induced by NG. A huge explosion with resultant fire had blown out a bungalow, with destructive damage predominantly above the ground, resulting in only 1 exterior wall and the foundation still in place. The victim was transferred to the hospital, and on the way, he admitted to undoing the natural gas fitting and to igniting the source. He survived for a short interval of time in the hospital before all resuscitative efforts failed. During autopsy, a special attention was paid to victim's identification and search for other injuries, not related to the explosion, so as to exclude or document homicidal injuries disguised by the subsequent explosion. The forensic pathologist should be aware of the different kinds of inflammable substances and integrate the findings with the scene information and the impression of the investigators at the scene

BACKGROUND: There are thousands of maize lines with distinctive normal as well as mutant phenotypes. To determine the validity of comparisons among mutants in different lines, we first address the question of how similar the transcriptomes are in three standard lines at four developmental stages. RESULTS: Four tissues (leaves, 1 mm anthers, 1.5 mm anthers, pollen) from one hybrid and one inbred maize line were hybridized with the W23 inbred on Agilent oligonucleotide microarrays with 21,000 elements. Tissue-specific gene expression patterns were documented, with leaves having the most tissue-specific transcripts. Haploid pollen expresses about half as many genes as the other samples. High overlap of gene expression was found between leaves and anthers. Anther and pollen transcript expression showed high conservation among the three lines while leaves had more divergence. Antisense transcripts represented about 6 to 14 percent of total transcriptome by tissue type but were similar across lines. Gene Ontology (GO) annotations were assigned and tabulated. Enrichment in GO terms related to cell-cycle functions was found for the identified antisense transcripts. Microarray results were validated via quantitative real-time PCR and by hybridization to a second oligonucleotide microarray platform. CONCLUSION: Despite high polymorphisms and structural differences among maize inbred lines, the transcriptomes of the three lines displayed remarkable similarities, especially in both reproductive samples (anther and pollen). We also identified potential stage markers for maize anther development. A large number of antisense transcripts were detected and implicated in important biological functions given the enrichment of particular GO classes

Suicide is second only to accidents as the most common cause of death for children and adolescents age 10 to 19 in Canada. All of the pediatric cases that were referred to the Hamilton Regional Forensic Pathology Unit from 1993 to 2002 were reviewed. For the purpose of this study, pediatric deaths were defined as deaths in the age group of 1 day up to and including 19 years of age. Specific criteria for suicide were applied to each case, independent of the manner of death issued by the coroner. The criteria were 3-fold. First, homicide had to be ruled out by the police investigation and autopsy findings. Second, the method had to be consistent with self-infliction. Finally, there had to be some evidence of suicidal intent. Questionable cases were discussed among the authors, and if reasonable intent could not be established, then the case was excluded. The autopsy and police reports were examined in detail regarding age, sex, location and method of suicide, presence of suicide notes, and any contributing psychologic factors or stressors. Of the 501 pediatric autopsies performed during the 10-year period, 31 (6%) met the criteria of suicide. The majority of cases (87%) were in older adolescents (age 15 to 19), and the male to female ratio was 2.4:1. Psychologic factors were identified in some of the cases, including depressed mood (77%), suicidal ideation (45%), previous suicide attempts (23%), and drug or alcohol problems (19%). Most of the suicides (61%) occurred in the victim's home, and 12 (39%) cases left a suicide note. In 9 cases (29%), alcohol or street drugs were detected postmortem, though in 8 cases toxicology was not performed. Hanging (48%) was the most common method of suicide, followed by firearms (13%), poisoning (10%), drowning (10%), and blunt force vehicular trauma (10%). Almost 60% of the male suicides were by hanging. No specific trend was identified in the 9 female suicides. These results were compared with similar studies within Canada and other countries. Overall, the method of suicide is dictated by what is convenient and readily available, though the acceptance of various suicide methods can change over time. Suicide prevention efforts should be tailored to address local trends

Three patients ranging in age from 58 to 72 years underwent mitral valve replacement for cardiogenic shock and severe mitral insufficiency associated with acute myocardial infarction. Correlation of the gross and microscopic findings confirmed the presence of partial rupture of both papillary muscles in all three cases. Papillary muscle rupture is an infrequent complication of acute myocardial infarction; double papillary muscle rupture an extreme rarity, previously only reported at autopsy. To our knowledge, the occurrence of postinfarction dual papillary muscle rupture in surgically excised valves has not been previously reported in the literature