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Biomedical subjects

L Riddick

Publications and source records attributed to L Riddick.

At least 19 recordsLinked to original sources
PubMed1999

Atlanto-occipital subluxation/dislocation: a "survivable" injury in children.

Atlanto-occipital dislocation occurs more often in children due to the laxity of the ligamentous structures anchoring the occiput to the axial skeleton. The mechanism of action usually involves a sudden acceleration-deceleration force on the head of the child. The dislocation usually severs the spinal cord at the foramen magnum, resulting in acute respiratory arrest. We have managed four patients who sustained this injury and arrived at our trauma center with signs of life. Two patients were hemodynamically unstable, had positive diagnostic peritoneal lavage, and underwent splenectomy. Both patients had obvious separation of the occiput and C1 on lateral cervical spine films. Both remained very unstable and died soon after celiotomy. The other two patients were stabilized, and both met criteria for brain death; one family agreed to organ donation. A 5-year analysis revealed 57 pediatric deaths, with 10 patients sustaining atlanto-occipital dislocations (17.5%). Nine of 10 patients sustained other injuries, but in only 2 patients were the injuries immediately life-threatening. With continued improvement in emergency medical systems and pediatric trauma care, we can expect to see more pediatric patients with this injury arriving in trauma centers with signs of life. In our experience, 50 per cent of patients may meet organ donor criteria, and our incidence of this injury (17.5%) reveals atlanto-occipital dislocation as a major contributor to pediatric trauma mortality.

Adolescent↗
PubMed1998

Automated coding of injuries from autopsy reports.

Medical examiners have a unique database about trauma victims, many, if not most, of whom died at the scene or in transit to a hospital and who, thus, never had their injuries documented by trauma surgeons and so never entered into a local or regional trauma registry. These trauma registries have assisted in assessing the magnitude of traumatic injuries in the community and in evaluating the community's emergency medical systems. Without information about those who are dead at the scene or who die in transit, these trauma registries are incomplete and the evaluations based on them inaccurate. The data about the 50% of trauma victims who never enter the medical system are lacking in these registries. Such information is present in the death investigation and autopsy reports in the various medical examiner/coroner offices in the country. To access this important information more easily in trauma registries, an expert computer system was developed. This pilot study presents the results of using that system to gather medical examiner data. Injury descriptions were abstracted from autopsy reports of 50 consecutive nonhospitalized persons fatally injured in Mobile County, Alabama and its environs. Injury descriptions for all cases were successfully coded in International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) and the Abbreviated Injury Scale (AIS-90) by an expert system. For some cases the expert system "requested" and received clarifying information, all of which was present in the medical records. This research demonstrates the feasibility of gathering accurate and consistent information on the estimated 50% of trauma deaths who do not reach a hospital and who are not included in acute care registries. Without data on such patients, our evaluation of trauma systems is incomplete and resources directed at prevention and treatment may be misapplied.

Abbreviated Injury Scale↗
PubMed1996

Cytoskeleton immunohistochemical study of early ischemic myocardium.

Previous studies on cytoskeletal changes of in vitro and in vivo animal models of ischemic myocardium have suggested the possibility of using alterations in cytoskeleton proteins as an early marker for the post-mortem diagnosis of myocardial ischemia in cases of sudden death due to coronary artery disease (CAD). In the present study, using the technique of ABC-immunohistochemistry, we examine the changes of three cytoskeletal proteins: vinculin, desmin and alpha-actinin in human myocardial samples taken from 14 cases of CAD sudden death and 13 cases of non-CAD death. Results of these examinations are compared with immunohistochemical changes of myoglobin and histochemical staining of hematoxylin and eosin and phosphotungstic acid, and Masson trichrome. Patchy and extensive loss of the three cytoskeletal proteins was demonstrated in the myocardium of victims who died 1 h or later following the onset of symptoms of ischemic myocardium. The pattern of cytoskeleton change is equivocal in the cases of CAD who died less than 1 h after the onset of symptoms and of the cases of non-CAD. In these cases, no significant histological change was observed. With less non-specific background changes and stronger positive staining, immunohistochemical staining of the three cytoskeletal proteins is more reliable than myoglobin, which has attracted the attention of many pathologists searching for anatomic evidence of ischemic myocardium in coronary artery disease.

Adolescent↗
PubMed1996

Portal vein embolization following shotgun-pellet injuries to the abdomen.

Multiple missile emboli are rare. The most likely setting for their occurrence is multiple penetrating injuries from birdshot. Such is this case of this 26-year-old man with birdshot injuries to the torso penetrating the portal vein and embolizing to the liver, producing infarcts and death.

Abdominal Injuries↗
PubMed1994

Comparison of adrenocorticotropin and adrenal steroid responses to corticotropin-releasing hormone versus metyrapone testing in patients with hypopituitarism.

We compared the responses of ACTH and cortisol (F) to corticotropin-releasing hormone (CRH) administration (ovine 1 microgram/kg i.v. bolus) with the responses of urinary 17-OH corticosteroids (17-OHCS) and serum deoxycorticosterone (DOC) to metyrapone administration (450 mg/m2/dose every 4 h x seven doses) in 16 hypopituitary patients. Glucocorticoid therapy for these patients was withheld for a minimum of 3 wk before testing. The CRH test was performed 3 d before or 3 wk after the metyrapone test was used to diagnose the ACTH reserve status. In nine ACTH-intact hypopituitary patients (post-metyrapone 17-OHCS > 12.2 mumol/m2/d; DOC > or = 11.5 nmol/L), the peak F (497-773 nmol/L) and ACTH (5.2-22 pmol/L) responses to CRH stimulation were similar to those of normal subjects (F peak = 554-993 nmol/L and ACTH peak = 6-25 pmol/L at 15-60 min). In one patient with partial ACTH deficiency (postmetyrapone 17-OHCS = 10.5 mumol/m2/d; DOC = 6 nmol/L), the peak F response was low and delayed (246 nmol/L at 180 min) and the peak ACTH response was normal (7 pmol/L). Six severely ACTH-deficient patients (postmetyrapone 17-OHCS < 5.4 mumol/m2/d; DOC < or = 3.4 nmol/L) had a low F response at 15-90 min in all, with a delayed rise in three at 120-180 min in response to CRH administration, whereas ACTH responses were variable: absent or low, normal, delayed, or persistently exaggerated. In conclusion, the CRH-stimulated F response pattern in hypopituitary patients was comparable to the urinary 17-OHCS and serum DOC response to metyrapone administration.(ABSTRACT TRUNCATED AT 250 WORDS)

17-Hydroxycorticosteroids↗
PubMed1994

Sickle cells and sudden death: morphologic abnormalities of the cardiac conduction system.

Sudden unexpected death has become increasingly recognized as an important clinical feature of both homozygous and heterozygous sickling syndromes, but the exact nature of its cause has remained unexplained. We have conducted special postmortem examinations of the cardiac conduction system and a coronary chemoreceptor from the hearts of two black males who had sickled erythrocytes. There were abundant foci of old and recent degeneration in the sinus node, atrioventricular node, and His bundle, as well as the coronary chemoreceptor. Many capillaries and small arteries were packed with sickled erythrocytes, among which small groups of aggregated platelets were also present. Focal fibromuscular dysplasia caused moderate to severe narrowing of many small coronary arteries, including those supplying the conduction system and chemoreceptor. These abnormalities are suggestive of electrical instability of the heart as at least one component of the lethal terminal events in some individuals with sickled erythrocytes. Both the foci of fibrosis and the focal fibromuscular dysplasia of small coronary arteries cannot be simply terminal or recent events but more likely take months or years in developing. For individuals with sickled erythrocytes, as in other examples of sudden death, there is a major element of chance concurrence of numerous otherwise independently less significant factors, but lethal cardiac electrical instability may be the final common pathway.

Adolescent↗
PubMed1993

Gunshot injuries in Mobile County, Alabama: 1985-1987.

Although much information about firearm fatalities has been published, few articles have characterized all types of gunshot victims, the weapons used, and the injuries sustained in a well-defined geopolitical unit. This study of 597 persons sustaining gunshot injuries serious enough to cause death or hospitalization in Mobile County Alabama during 1985-1987, addresses that deficit. The overall rate of these 597 seriously gunshot-injured victims was 53/100,000 population per annum. Of the 597 victims, 215 died, resulting in a rate of 18.9 per 100,000 population per annum. Demographic characteristics of the homicide victims, predominantly young black men, and the suicide victims, predominantly middle-aged and elderly white men, are similar to those reported from other parts of the country. Assault victims accounted for the largest (316) number of victims: again, young black men also constituted the largest demographic group among assault victims. Handguns accounted for 71% of the weapons used. No assault type weapons were employed. Head, neck, and chest wounds led with the greatest fatality rates. Information about nonfatally wounded victims, particularly data about the weapons, proved difficult to obtain. This was one of the many problems encountered in this type of project and, consequently, is discussed at some length. Additional population-based studies using prospective methods and a variety of investigators, including persons knowledgeable of firearms, are needed.

Adolescent↗
PubMed1992

Normal and elevated 3 alpha-androstanediol glucuronide concentrations in women with various causes of hirsutism and its correlation with degree of hirsutism and androgen levels.

We investigated peripheral androgen metabolic activity in 54 hirsute females (HF) by evaluating the serum 3 alpha-androstanediol glucuronide (3AG) concentration, hirsutism score (HS), and etiology of hirsutism. Based on basal and ACTH-stimulated steroid profiles (1 h post-Cortrosyn, 0.25 mg, i.v. bolus), the causes of hirsutism were determined to be increased adrenal androgen production (greater than 2 SD above normal mean), increased ovarian testosterone (T) production (greater than 2 SD above normal mean basal T of ovarian source only), or idiopathic cause (normal steroid profile). Serum 3AG levels in each group of HF were significantly higher (P less than 0.01-0.001) than those in normal females [normal: 2.9 +/- 0.94 nmol/L (n = 28); HF: increased adrenal androgen production of undefined cause, 7.7 +/- 7.5 nmol/L (n = 14); 21-hydroxylase deficiency, 7.6 +/- 7.4 nmol/L (n = 5); increased ovarian T production 5.5 +/- 3.5 nmol/L (n = 18); idiopathic cause, 5.8 +/- 4.8 nmol/L (n = 17)]. However, normal 3AG levels (less than 5.2 nmol/L) were present in 50-67% of HF in each group. Collectively, 3AG levels in HF correlated significantly (P less than 0.01) with dehydroepiandrosterone (DHEA; r = 0.41) and DHEA sulfate (DS; r = 0.44), while the correlation with androstenedione (r = 0.15) or T (r = 0.19) was not significant. Serum 3AG and adrenal androgen levels decreased in all subjects after dexamethasone treatment (0.5-1 mg at hour of sleep; 2 mg/day for 3-5 days). The correlation between 3AG and HS was significant (r = 0.6-0.74; P less than 0.01-0.001) only in HF with increased adrenal androgen secretion and idiopathic cause, and was not significant (r = 0.42) in HF with increased ovarian T secretion. There was no significant correlation between androgen levels and HS. We conclude that the serum 3AG level was not consistently elevated in HF and did not differ significantly between the various causes. Significant correlations between 3AG and DHEA/DS levels, and the simultaneous decrease in 3AG and adrenal androgens after dexamethasone administration in HF suggest that adrenal androgens contribute significantly to 3AG production. The significant correlation between 3AG and HS in HF with increased adrenal androgen secretion and idiopathic cause indirectly suggests an adrenal androgen contribution to both 3AG production and hirsutism in these HF. The insignificant correlation between 3AG and HS in HF with increased ovarian T secretion may result from a confounding effect of ovarian T on hirsutism.

Adolescent↗
PubMed1992

Combined bromocriptine and growth hormone (GH) treatment in GH-deficient children with macroprolactinoma in situ.

Experience with PRL-secreting macroadenomas in the pediatric and adolescent population is limited. Although use of synthetic GH after treatment of central nervous system tumors in children without active disease is accepted practice, reports of GH use in patients with central nervous system tumors in situ are rare. Furthermore, the effect of GH on tumor growth is not known. We report GH treatment (10 and 11.5 months), concomitant with bromocriptine (BC; dopamine agonist) therapy in two children, a 15.5-yr-old male and a 15.5-yr-old female, with PRL-secreting macroadenomas in situ. Surgical resection was deemed undesirable because of the risk of major morbidity due to the large size of the tumors and the close proximity to major vessels. Both patients were GH deficient and had heights below the fifth percentile coupled with arrested pubertal progress. During BC therapy, a decrease in tumor size and a reduction in serum PRL levels occurred in both patients, which continued after the addition of GH treatment. Neither patient experienced changes in visual acuity during combined treatment, and both experienced marked improvement in growth velocity. We conclude that in children with PRL-secreting tumors and GH deficiency in whom surgery is not advised, combined treatment with BC and GH appears to be safe and efficacious. To our knowledge, these patients represent the first report of the combined therapeutic use of BC and GH as the primary mode of treatment in children with prolactinoma in situ with documented GH deficiency.

Adolescent↗
PubMed1991

3 alpha-androstanediol glucuronide in virilizing congenital adrenal hyperplasia: a useful serum metabolic marker of integrated adrenal androgen secretion.

To determine whether serum 3 alpha-androstanediol glucuronide (3AG) reflects the overall effect of integrated adrenal androgen secretion in the virilizing form of congenital adrenal hyperplasia (CVAH), circadian levels (0800, 1200, 1600, and 2000 h) of serum 3AG and 17-hydroxyprogesterone (17OHP) or 11-deoxycortisol (S), androstenedione (A), testosterone (T), and 24-h urinary 17-ketosteroids (17KS) were examined in seven patients (pts) with classical 21-hydroxylase deficiency (21OHD) and one pt with classical 11 beta-hydroxylase deficiency (11 beta OHD). Hormonal studies were conducted during the second day of dexamethasone (Dex) administration (2 mg/day). In five poorly controlled CVAH pts, including the 11 beta OHD pt, highly elevated baseline morning (AM) serum 17OHP or S as well as A levels, and elevated AM T levels in three pts decreased markedly in the evening (PM), while elevated serum 3AG showed no significant circadian changes; 17KS levels were markedly elevated for age. During Dex, moderately or slightly elevated AM 17OHP, A, or T in two to four pts with 21OHD decreased to the normal range in the PM. In the pt with 11 beta OHD, S, A, and T levels were suppressed. 3AG levels were modestly elevated or normal, without circadian changes, in these pts; 17KS levels were elevated or normal. In two other 21OHD pts, modestly elevated AM baseline 17OHP and A levels decreased in the PM; elevated AM T decreased in one pt in the PM; modestly elevated 3AG levels showed no circadian changes; 17KS levels were modestly elevated. During Dex, normal or slightly elevated serum steroids and 17KS levels were associated with normal or high normal 3AG levels without circadian changes. In one postpubertal female with 21OHD, modestly elevated AM baseline 17OHP levels decreased at 2000 h; normal A and T levels throughout the day and low normal 17KS were associated with slightly low 3AG levels, without circadian variation. During Dex treatment, normal 17OHP, A, T, and low 17KS levels were associated with low 3AG levels without circadian variation. In all pts as a group, an excellent correlation (r = 0.9) was found between either 0800 h or mean, or 2000 h serum 3AG levels and 17KS. In addition, AM and PM serum 3AG levels in five normal women were similar. We conclude that the high correlation between serum 3AG and urinary 17KS and the absence of a significant circadian variation in 3AG indicate that serum 3AG, regardless of sample time, is a useful metabolic index of integrated adrenal androgen secretion in CVAH.

17-Ketosteroids↗
PubMed1990

Cardiac abnormalities demonstrated postmortem in four cases of accidental electrocution and their potential significance relative to nonfatal electrical injuries of the heart.

Death from accidental electrocution is generally thought to be due to an arrhythmia, but little is known of the anatomic changes in the heart and almost nothing is known about the conduction system itself. We have studied the hearts of four men who died from electrical accidents and directed particular attention to the coronary arteries, conduction system, and neural structures of the heart. In every heart there was widespread focal necrosis involving all the myocardium and including the specialized tissue of the sinus and atrioventricular nodes. In all four hearts there was contraction band necrosis of smooth muscle cells in the tunica media of the coronary arteries. Cells in the His bundle and bundle branches were less affected. Neural structures of the heart were minimally involved. We also sought any cardiac changes of a chronic nature that may have predisposed to a fatal arrhythmia. Two of the four hearts were slightly enlarged, and increased myocardial mass predisposes to ventricular fibrillation and makes it more difficult to revert. One heart exhibited focal fibromuscular dysplastic narrowing of small coronary arteries, including that artery supplying the coronary chemoreceptor. Another heart had fatty deposition extensively present within and around the sinus and atrioventricular nodes. Thus numerous abnormalities specifically attributable to the electrocution help explain the pathogenesis of the electrical instability known to occur. But in three of the four hearts there were also chronic abnormalities favoring electrical instability but predating the electrocution.

Adult↗
PubMed1990

Sudden death due to isolated acute infarction of the His bundle.

A 29 year old black man considered to be in good health died suddenly and unexpectedly. At postmortem examination there were no significant gross abnormalities, all drug screens were normal and sicklemia was not present. Special studies of the cardiac conduction system demonstrated isolated acute infarction of the His bundle, with no similar evidence of myocardial infarction anywhere else in the heart. The atrioventricular (AV) node artery was moderately narrowed, but its branch supplying the His bundle was occluded greater than 95% by focal fibromuscular dysplasia. There were no other significant coronary lesions or other abnormalities in the heart.

Adult↗
PubMed1990

Atrial natriuretic factor in hydrops fetalis caused by Rh isoimmunisation.

Plasma concentrations of atrial natriuretic factor were determined by radioimmunoassay in 16 human fetuses of between 19 and 38 weeks' gestation. Fifteen fetuses had varying degrees of anaemia as a result of Rh isoimmunisation, and one fetus was normal. Eight fetuses had ultrasonographic evidence of severe hydrops fetalis and an additional three fetuses had mild hydrops. Severely hydropic fetuses were more anaemic and immature than those with mild or no hydrops. Among fetuses from which samples were taken before in utero transfusion, concentrations of atrial natriuretic factor were higher in those with severe hydrops than in the other groups. An inverse relationship between the haemoglobin concentration and that of atrial natriuretic factor was found. In four fetuses in which severe hydrops resolved after intravascular transfusions in utero, there were significant decreases in plasma atrial natriuretic factor concentrations; in the fifth fetus the decrease was less pronounced. Raised concentrations of atrial natriuretic factor in fetuses with severe anaemia and hydrops may be the result of atrial natriuretic factor release induced by hypoxia.

Atrial Natriuretic Factor↗
PubMed1989

Homicide in Alabama: an analysis of urban, suburban and rural murders in the Deep South.

Eleven hundred forty-four (1144) homicides occurring in Alabama, U.S.A. during a 2-year period are presented and analyzed according to the demographic parameters of the victims, location in urban, suburban, or rural community, type of homicide based on a medical examiner's classification, presence of drugs, weapon employed and other factors. Urban dwellers, Blacks and males are found to be at high risk. Alcohol is much more prevalent than other drugs in homicide victims. Although the handgun is the weapon most commonly used throughout the state, in the rural regions the longgun is used almost as often. The difficulty of making valid comparisons with other homicide studies is discussed and the establishment of a uniform classification of homicides urged.

Adolescent↗
PubMed1989

The mirror's use in suicide.

Eleven suicides in which the victim took his or her life while looking into a mirror are presented. The psychoanalytic implications of this extreme form of narcissism are discussed. Investigators should have a high index of suspicion of suicide in cases where a dead body is positioned in front of or near a mirror.

Adult↗