Biomedical subjects

J Smialek

Publications and source records attributed to J Smialek.

34 records · Page 2Linked to original sources

PubMed1996

Effect of age, race, body surface area, heart weight and atherosclerosis on coronary artery dimensions in young males.

Compensatory arterial enlargement in response to atherosclerosis has been demonstrated for the left main coronary artery. Only limited data is available on the interaction of patient characteristics and atherosclerosis with coronary artery dimensions. The purpose of the present study was to evaluate the influence of age, race, body habitus, heart weight and atherosclerosis on coronary artery dimensions of young males. Hearts from 137 young men (age 32 +/- 8 years; 78 black, 59 white) with unnatural deaths (homicide, suicide, accident, drug overdose) were perfusion-fixed, and histologic sections were obtained from the left main, proximal left anterior descending and left circumflex coronary arteries. Computerized planimetry was performed on Movat stained sections. Multiple regression analysis was used to evaluate the relative contribution of plaque size, age, race, heart weight and body surface area on coronary dimensions and compensatory enlargement in response to atherosclerosis. In the left anterior descending and left main coronary arteries, black race, body surface area and age were independent predictors of increased lumen area. In the left circumflex, age was a predictor of lumen area. Plaque area, black race and body surface area independently predicted increased area enclosed by the internal elastic lamina area. There was compensatory enlargement of internal elastic lamina with increasing plaque size in both races in the three arteries, but the percent luminal stenosis was greater in whites due to smaller artery size. Luminal narrowing did not develop until plaques occupied 30% of internal elastic lamina area. Among a population of young men with non-cardiac deaths, blacks have larger lumen and area enclosed by internal elastic lamina than whites. Age and body surface area are major determinants of lumen areas, and compensatory arterial enlargement was seen in all examined arteries in the present study.

Adolescent↗

PubMed1995

Sudden death as a result of heart disease in morbid obesity.

Patients with morbid obesity have high rates of sudden, unexpected cardiac death. The mechanism of death in these patients is uncertain. Twenty-eight patients with morbid obesity (22 sudden cardiac deaths, 6 unnatural deaths) were compared to 11 age-matched nonobese patients with traumatic deaths. Heart weight, left ventricular cavity diameter, left and right ventricular wall thickness, ventricular septal thickness, epicardial fat thickness, and extent of coronary artery atherosclerosis were determined; myocyte size, nuclear size, and degree of interstitial fibrosis were calculated morphometrically. Mean heart weights in the patients with morbid obesity were increased but remained constant as a percentage of body weight. Of the gross parameters, only heart weight and left ventricular cavity size were independent predictors of obesity. Of microscopic parameters, only nuclear area was an independent predictor of obesity. Of 22 patients with morbid obesity, dilated cardiomyopathy was the most frequent cause of sudden cardiac death in (10 patients), followed by severe coronary atherosclerosis (6), concentric left ventricular hypertrophy without left ventricular dilatation (4), pulmonary embolism (1), and hypoplastic coronary arteries (1). The cardiomyopathy of morbid obesity is characterized by cardiomegaly, left ventricular dilatation, and myocyte hypertrophy in the absence of interstitial fibrosis. It is the most common cause of sudden cardiac death in these patients.

Adult↗

PubMed1995

Problems in forensic cardiovascular pathology.

Do we have a magic yardstick that will establish whether SCD of the patient is definitely caused by the presence of an underlying abnormality? We are afraid that in most cases of cardiac disease the cause of death is at best probable, or even presumed. It has always been that circumstantial evidence has helped us establish that the cause of death is related to the anatomic abnormality. Even the presence of severe coronary artery disease in a patient who dies suddenly, especially in the absence of a thrombus, cannot be stated categorically to be the cause and effect. With the knowledge we have today, establishing cause and effect are difficult in most cases of SCD.

Adolescent↗

PubMed1995

Localization of human immunodeficiency virus 1 RNA in thymic tissues from asymptomatic drug addicts.

Thymic tissue was collected from 11 human immunodeficiency virus 1 (HIV-1)-seropositive drug users who died suddenly of drug intoxication or trauma. None of the 11 individuals had symptoms related to HIV-1 infection or were known to be seropositive for HIV-1 before death. Secondary B-cell follicles were present in every thymus, and Warthin-Finckeldey giant cells were noted in three cases. These follicles were enlarged or fragmented and appeared similar to those in lymph nodes excised from the same individuals. Localization of viral RNA by in situ hybridization demonstrated abundant virus in a follicular center cell distribution within hyperplastic follicles and in scattered medullary lymphocytes. In nine thymus glands from seronegative drug addicts and five thymus glands from seronegative trauma victims who were not drug addicts, secondary follicles were absent and no hybridization signal was present. Other than the presence of germinal centers associated with HIV-1 RNA, there were no histologic differences among the thymus glands of seropositive drug addicts, seronegative drug addicts, and seronegative controls without a history of drug abuse. We conclude that the thymus gland in early stages of infection with HIV-1 is characterized by induction of secondary B-cell follicular hyperplasia in medullary tissues, the germinal centers of which contain abundant viral RNA.

Adult↗

PubMed1994

Systemic lymphadenopathic histology in human immunodeficiency virus-1-seropositive drug addicts without apparent acquired immunodeficiency syndrome.

We examined lymph nodes from multiple sites in 50 individuals infected with human immunodeficiency virus (HIV-1) who died accidentally of drug overdoses and in whom there was no evidence of opportunistic infection. The size, histologic pattern, presence of Warthin-Finkeldey-type giant cells, and estimation of CD4 cell count of these lymph nodes were compared with those of 13 seronegative drug addicts (controls). Lymph nodes from seropositive individuals were slightly but significantly larger than those of controls. Lymph nodes from seropositive cases were much more likely to contain secondary follicles (90%) than were those from controls (20%). Unlike follicles in control nodes, most secondary follicles in the seropositive cases were in various stages of fragmentation and involution. As follicular changes progressed, there was a decrease in CD4 cells and an increase in intrafollicular and paracortical plasma cells. Plasmacytosis was much more prevalent in lymph nodes from seropositive individuals than in controls. Warthin-Finkeldey-type giant cells were present in at least one node in 29 of 50 seropositive cases, were most numerous in those showing follicular hyperplasia with fragmentation (45% of cases), and were especially numerous in Peyer's patches (61% of cases). There was generally good concordance of HIV-1-associated follicular morphology among diverse lymph node groups. There is prolonged generalized, mild hyperplastic lymphadenopathy with frequent syncytial cells in intravenous drug addicts with asymptomatic HIV-1 infection.

AIDS-Related Complex↗

PubMed1994

Involvement of mast cells in sudden infant death syndrome.

The pathogenesis of sudden infant death syndrome (SIDS) is elusive and probably multifactorial. The occurrence of mast cell activation in SIDS was assessed in this study by measuring concentrations of tryptase, a neutral protease produced mainly by mast cells, in postmortem sera from term infants with SIDS and from age-matched control infants who died unexpectedly at home from a known cause. Tryptase levels were significantly higher in the 50 infants with SIDS than in the 15 control infants (p = 0.0004). Forty percent of the infants with SIDS and none of the control infants had a tryptase level greater than 10 ng/ml, the threshold chosen to indicate premortem mast cell activation. An infant with SIDS had a 20-fold higher chance of having an elevated tryptase level compared with a control infant. The postmortem interval did not influence these results. Thus mast cell-mediated anaphylaxis is likely to be the pathogenetic mechanism involved in some but not all SIDS cases. Recognition of this pathway as operative in SIDS should facilitate a more precise identification of the allergens involved, the processes leading to mast cell activation, and procedures to identify those infants at risk for anaphylaxis, and should, in time, lead to better therapeutic interventions aimed at preventing this specific cause of SIDS.

Anaphylaxis↗

PubMed1994

A mexiletine intoxication.

A case is presented of a 26-year-old white male with a history of depression and previous suicide attempts. No anatomic cause of death was determined at the autopsy. Comprehensive toxicological analysis of the blood and urine specimens identified mexiletine, a class 1B antiarrhythmic drug. Mexiletine was detected by gas chromatography and confirmed by gas chromatography-mass spectrometry. Quantitations were as follows: heart blood, 38 mg/L; subclavian blood, 14 mg/L; urine, 370 mg/L; liver, 190 mg/kg; kidney, 170 mg/kg; vitreous humor, 17 mg/L; and bile, 440 mg/L. The medical examiner ruled that the cause of death was mexiletine intoxication and the manner of death was suicide.

Adult↗

PubMed1993

Does handgun legislation change firearm fatalities?

When comparing firearm fatalities for children under 16 years of age before and after handgun legislation enactment in Maryland, firearm fatalities increased overall. A decrease in accidental deaths in the home perhaps reflects a response to public education and awareness. More aggressive handgun legislation is imperative to reverse this public health trend.

Adolescent↗

PubMed1993

Nonatherosclerotic narrowing of the atrioventricular node artery and sudden death.

OBJECTIVES: This study was undertaken to determine whether thickening of the atrioventricular (AV) node artery is a cause of sudden cardiac death. BACKGROUND: Thickening of the AV node artery has been implicated as a cause of sudden death primarily on the basis of case reports. Few pathologic studies have compared subjects who died of sudden cardiac death with normal control subjects who died traumatically. METHODS: The AV node artery in 27 patients with unexplained sudden cardiac death (mean age 24.8 +/- 7.4 years) was compared with that in 17 control subjects who died traumatically (mean age 25.6 +/- 7.0 years). No anatomic cause of death was found at autopsy in the subjects with sudden death, all of whom died of presumed cardiac arrhythmias. The conduction system of all hearts was studied by semiserial sections and Movat pentachrome stains. At the point of greatest narrowing of the AV node artery, the outer circumference and lumen outline were traced by computerized morphometry, the ratio of outer vessel area to lumen area was calculated and the histopathologic changes were noted. RESULTS: The rank-sum of ratios was significantly greater in the sudden death group than in the control group (p = 0.031, Wilcoxon rank-sum/Mann-Whitney statistic). A dysplastic AV node artery with significant acid mucopolysaccharide deposition was seen almost exclusively in the sudden death group (12 of 27 vs. 1 of 17, p = 0.006). In 10 subjects with sudden death a dysplastic AV node artery was narrowed > 2 SD over the control value; half of this subgroup died during exercise and one third had a family history of sudden unexplained cardiac death. CONCLUSIONS: Dysplasia of the AV node artery may contribute to death in a substantial portion of patients with unexplained sudden death, and such death is often associated with exercise and a family history of unexplained sudden death.

Adult↗

PubMed1993

Safety belt restraints and compartment intrusions in frontal and lateral motor vehicle crashes: mechanisms of injuries, complications, and acute care costs.

A 3-year prospective study examined 76 frontal (F) and 45 lateral (L) motor vehicle crash (MVC) patients with regard to seatbelt restraint use and occupant compartment contact and intrusion injuries. These 121 MVC victims with multiple injuries (39 belted [B] and 82 non-belted [NB]), admitted to a level I trauma center, were studied by accident reconstruction and medical data analysis. They had a MVC mean impact velocity (delta V) of 30 +/- 11 mph and an injury Severity Score of 29 +/- 12. Proper restraint use reduced brain injury in F MVCs (30% FB vs. 47% FNB) but had no effect in L MVCs (63% LB vs. 30% FB [p < 0.06]). Belt use did not protect against lung, liver, spleen, pelvis, or lower extremity (LE) injury. These appeared to be more a function of crash direction, with LE injuries higher in F crashes (p < 0.04) and pelvis injuries (p < 0.001) higher in L crashes. In FB crashes, however, properly used safety restraints were the primary cause of bowel or colon injuries (p < 0.006). Belts did not prevent thoracic or abdominal solid organ injuries in L crashes. Contact-intrusions (CI) of the car occupant compartment in F crashes were the main cause of brain (A-pillar), lung and liver (steering wheel and instrument panel), and LE (toepan) injuries; but in L crashes, side-door CI caused lung, aorta, liver, and pelvic injuries. In contrast, contact-only (CO) injuries of the steering assembly were mainly responsible for injuries to the lung, heart, and liver in F crashes, and side-door CO for lung, liver, and spleen injuries in L crashes. Deaths and complications after injury were higher among F MVC occupants, or when delta V was > or = 30 mph. Hospital and professional costs reflect the complex care needed for victims of multiple injuries: FB, $99,000; FNB, $95,000; LB, $75,000; LNB, $79,000; total, $10.7 million. Present vehicle safety standards are not adequate, and structural design changes are needed to improve restraints and protect occupants from intrusion-related injuries.

Abdominal Injuries↗

PubMed1993

Postmortem localization of HIV-1 RNA by in situ hybridization in lymphoid tissues of intravenous drug addicts who died unexpectedly.

The histopathological alterations in lymphoid tissues and the presence of human immunodeficiency virus (HIV-1) RNA were studied in 25 consecutive autopsies of seropositive, apparently asymptomatic, intravenous drug overdose victims without palpable lymphadenopathy. The majority of lymphoid tissues in a given person showed either a combination of follicular hyperplasia and fragmentation or a combination of involution and depletion. Individuals with involuted and depleted lymphoid tissues were significantly older than those individuals with hyperplasia and fragmentation of follicles. Lymph nodes from individuals with hyperplasia with or without fragmentation were slightly but significantly larger than control nodes from seronegative persons. In tissues from infected cases, HIV-1 RNA was demonstrated by in situ hybridization in 49% of follicular centers showing hyperplasia, 62% of hyperplastic fragmented follicles, and 66% of involuted follicles in a distribution of follicular dendritic cells. No signal was detected in tissues demonstrating follicular depletion or nodes from seronegative persons. Scattered inter- and intrafollicular lymphoid cells with positive signal were present only in nodal tissues with follicular hyperplasia without involution. Tonsils, inguinal, axillary, mediastinal, supraclavicular, mesenteric nodes, and spleen were positive for HIV-1 RNA in 78%, 76%, 67%, 65%, 58%, 50%, and 28% of cases, respectively, and the prevalence of positivity reflected the presence of follicles. We conclude that the clinically asymptomatic period of HIV-1 infection is characterized by pathological stages in lymphoid tissues that have distinct histological alterations and distribution of viral RNA.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Increase in atherosclerosis and adventitial mast cells in cocaine abusers: an alternative mechanism of cocaine-associated coronary vasospasm and thrombosis.

Coronary vasospasm has been implicated as a cause of myocardial ischemia and sudden cardiac death in cocaine abusers. However, the mechanism or mechanisms remain unknown. Autopsy records (n = 5,871) from the medical examiner's files at Baltimore, Maryland and northern Virginia were examined and 495 persons (8.4%) were identified with positive toxicologic findings for cocaine. Of these, six subjects (1.2%) had total thrombotic occlusion, involving primarily the left anterior descending coronary artery. The mean number of adventitial mast cells per coronary segment and the degree of atherosclerosis were determined. These observations were compared with findings in age- and gender-matched subjects who died from cocaine overdose and in patients who had sudden cardiac death (acute thrombosis) without a history of illicit drug abuse. There were significantly more mast cells in subjects with cocaine-associated thrombosis than in the other groups. The number of mast cells showed a significant correlation with the degree of cross-sectional luminal narrowing (r = 0.68) in subjects with cocaine-associated thrombosis but not in subjects with sudden death due to thrombosis (r = 0.34, p less than 0.03). Subjects with cocaine-associated thrombosis also had significant coronary atherosclerosis without plaque hemorrhage (five had one or more vessels with greater than 75% cross-sectional area luminal narrowing) despite a mean age of 29 +/- 2 years. These findings suggest that adventitial mast cells may potentiate atherosclerosis and vasospasm, thrombosis and premature sudden death in long-term cocaine abusers.

Adult↗

PubMed1990

Characteristics of pediatric firearm fatalities.

An increase in the awareness of the problem of gunshot fatalities in children has occurred nationwide over the last year. Unintentional firearm deaths are more common among children and young adults. These deaths may be addressed by preventive measures beyond those available for pediatric firearm suicide and homicide. This study focuses on the incidence of fatal gunshot injuries in children under 16 years of age during the years 1979 through 1987 in our state. Over the past 9 years 132 children (0 to 16 years) were shot and killed as a result of firearm injuries (M:F ratio, 3:1). No difference in absolute number in racial distribution existed. Deaths were classified as homicide, 61 (46%); accidental, 33 (25%); suicide, 29 (22%); undetermined, 7 (5%); and other, 2 (1.5%). Over 70% of these fatal injuries occurred in the home environment. Types of weapons involved included handguns (48%), shotguns (22%), rifles (17%), unspecified weapon (12%), and air rifle (1%). In a large number of cases, guns were found in the home unsecured. The perpetrator was known by the victim in 64 instances, while unknown in 27. Thirty-nine self-inflicted wounds and two shotgun blasts in the line of fire accounted for the remaining deaths. The most common anatomical injury and ultimate cause of death was cranial central nervous system (CNS) (62%), followed by chest/mediastinum (20%), abdomen (10%), and other (8%). A child who has sustained a firearm injury is more likely to know the perpetrator, be killed in the home by a readily available unsecured firearm, and die from severe head injury.

Accidents, Traffic↗

PubMed1985

Quantitative evaluation of the extent of hepatic enzyme changes in Reye syndrome compared with normal liver or with non-Reye liver disorders: objective criteria for animal models.

Five enzymes were measured in 50 liver specimens (18 normal liver, 20 Reye liver, 12 diverse liver disorders other than Reye syndrome). The enzymes were: glutamic dehydrogenase (E.C. 1.4.1.3), monoamine oxidase (E.C. 1.4.3.4), lactate dehydrogenase (E.C. 1.1.1.27), D-glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49), catalase (E.C. 1.11.1.6). The Reye syndrome group showed significant decreases in glutamic dehydrogenase (56%) and monoamine oxidase (70%) compared to normal control tissue and these changes were not characteristic of the non-Reye liver disorder group as a whole. Neither catalase nor lactate dehydrogenase appeared to be altered significantly in the Reye or in the abnormal control group compared with normal controls. Thus, only the prominent decreases in the mitochondrial enzyme activities appeared to be highly characteristic of Reye syndrome. Paradoxically, the means of the five hepatic enzymes and the admission levels of two serum enzymes indicative of liver damage (alanine and aspartate aminotransferase) were remarkably similar for both survivors and nonsurvivors of Reye syndrome.

Adolescent↗

PubMed1983

Toxicological and pathological findings in fatalities involving pentazocine and tripelennamine.

Toxicological and pathological findings are described in fatalities involving pentazocine (Talwin) and tripelennamine (Pyribenzamine). Procedures using thin-layer chromatography, gas chromatography, ultraviolet spectrophotometry, and spectrophotofluorometry are described, as well as the quantitative analysis of biological specimens of drug abuse and homicide victims. Microscopic findings in lung specimens from drug abuse deaths are also described.

Chromatography, Gas↗

PubMedDate not supplied

The prevalence of the neuropathological lesions of Alzheimer's disease is independent of race and gender.

Senile plaques (SP) and neurofibrillary tangles (NFT) are the lesions characteristic of Alzheimer's disease (AD). In this study, we examined variation in the proportion of individuals who had these lesions by race, age, and gender in a series of 138 autopsies conducted at the Office of the Chief Medical Examiner of the State of Maryland between 1990 and 1998. Cases were selected on the bases of age between 40 to 79 years and non-natural manner of death, and included 73% males, 61% subjects < 65 years of age, and 42% African Americans. Observations were conducted on histologic sections of the hippocampus, entorhinal cortex, and inferior temporal cortex stained with silver (Hirano method) and immunostained for Abeta-amyloid. We found that SP and NFT are strongly associated with age. These lesions begin to appear in the early to late 40s, depending on the anatomic location, and become common in the 6th decade, preceding by one to two decades the age at which AD becomes clinically prevalent. No difference in the prevalence of SP or NFT was found by gender or between whites and African Americans. The latter is in contrast to epidemiologic studies that suggest AD is more prevalent in African Americans than in whites.

Adult↗