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Biomedical subjects

J A Towbin

Publications and source records attributed to J A Towbin.

158 records · Page 9Linked to original sources
PubMed1986

Use of the interactive videodisc to teach pathology: a preliminary report.

Although use of computers in education dates to the early 1960s,1-3 it is only with the arrival of the "microcomputer revolution" that computers have become economically feasible in medical education. The advent of inexpensive and relatively powerful microcomputers initiated something of a chain reaction; microcomputers became available for educational purposes, thus creating a market for educational software. This accelerated development of educational software in turn made microcomputers more useable. While synergistic hardware and software development has occurred repeatedly in the microcomputer industry, it is only in the beginning stages in medical education. This paper presents a discussion of the development of one computer-assisted instructional program that utilizes an interactive videodisc format.

Computer-Assisted Instruction↗
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Left ventricular noncompaction cardiomyopathy in association with trisomy 13.

In recent years, left ventricular noncompaction (LVNC) has been recognized as a distinct form of cardiomyopathy with its own clinical presentation and natural history. More than 100 cases of LVNC have been described in children. Although LVNC has been described in association with metabolic disorders such as Fabry's disease or genetic disorders such as Roifman's syndrome, this case represents the first report of LVNC in a child with trisomy 13.

Cardiomyopathy, Dilated↗
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A prospective evaluation of nesiritide in the treatment of pediatric heart failure.

This study sought to determine the potential of recombinant B-type natriuretic peptide (nesiritide) for the treatment of pediatric decompensated heart failure. Nesiritide is a widely used and effective treatment for decompensated heart failure (HF) in adults, but its safety and efficacy in pediatric patients is unclear. Outcomes of 55 separate nesiritide infusions of varying durations in 32 patients (13 males and 19 females; mean age, 8.01 years; range, 0.01-20.4) were evaluated prospectively. All patients received nesiritide in the intensive care unit. The starting dose (0.01 microg/kg/min) was titrated to a maximum of 0.03 microg/kg/min. All patients were monitored for clinical signs and symptoms, hemodynamics, urine output, electrolytes, oxygen requirements, and oral intake. Functional status was assessed by patients and/or their parents. All patients successfully underwent initiation and titration of nesiritide infusion. No hypotension or arrhythmias were noted during 478 cumulative days of therapy. Nesiritide was given safely with vasoactive medications. Mean urine output improved from 2.35 +/- 1.71 cc/kg/hr on the day before nesiritide initiation (baseline) to 3.10 +/- 1.94 cc/kg/hr on day 4 of treatment (p < 0.01). Serum creatinine decreased from 1.04 to 0.92 mg/dl (p = 0.096), mean central venous pressure from 13 to 7 mmHg (p = 0.018), and mean weight from 30.4 to 29.7 kg (p < 0.001) with therapy. Thirst, as subjectively assessed by patients old enough to respond, decreased with infusion in 31 of 42 cases (74%). Mean New York Heart Association functional class improved significantly (p < 0.001). Nesiritide infusion, alone or in combination, is a safe treatment for decompensated HF in pediatric patients. It is associated with decreased thirst and improved urine output and functional status, and it may be efficacious in the treatment of pediatric HF.

Adolescent↗
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Current concepts in long QT syndrome.

Sudden cardiac death occurs in the United States with an incidence of more than 300,000 persons per year. The underlying cause of death is commonly considered to be due to primary or secondary arrhythmias. In young persons in whom no structural heart disease can be identified, the long QT syndromes (LQTS) are commonly considered as likely causes. Multiple genes causing LQTS have been identified thus far, all of which encode cardiac ion channels. These include two potassium channel alpha subunits (KVLQT1 and HERG), two potassium channel beta subunits (minK and MiRP1), and one sodium channel gene (SCN5A). The purpose of this review is to describe the current understanding of the molecular genetics of LQTS and the resultant phenotypes, particularly in young patients.

Adrenergic beta-Antagonists↗
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Molecular screening by polymerase chain reaction detects panleukopenia virus DNA in formalin-fixed hearts from cats with idiopathic cardiomyopathy and myocarditis.

Viral myocarditis has been suggested as an etiology for cardiomyopathy in several mammalian species. Myocarditis and idiopathic cardiomyopathy have been reported in the domestic cat, although a viral etiology has not been demonstrated. Because of the continuing interest in the potential relationship between viral myocarditis and cardiomyopathy, we evaluated hearts from cats with spontaneous, idiopathic cardiomyopathy for viral genomic material within myocytes by polymerase chain reaction, and for the presence of myocarditis by light microscopy. Thirty-one (31) formalin-fixed hearts from domestic cats who died of idiopathic cardiomyopathy were randomly selected from pathology archives. Seventeen (17) formalin-fixed hearts from healthy cats were similarly selected as normal controls. The polymerase chain reaction (PCR) was used to evaluate myocardial tissue for the presence of viral genome from feline panleukopenia virus, herpes virus, calici virus, and corona virus. Hearts were examined using light microscopy for histologic evidence of myocarditis according to the Dallas criteria. Panleukopenia virus was identified by PCR in 10 of 31 cats with cardiomyopathy but in none of the controls. Neither cardiomyopathic or control cats tested positive by PCR for herpes virus, calici virus, and corona virus. Myocarditis was detected by histologic examination in 18 of 31 cardiomyopathic cats and in none of 17 control cats. Myocarditis and or feline panleukopenia virus genome was detected in felines with idiopathic hypertrophic, dilated, and restrictive cardiomyopathy, suggesting a possible role of viral infection and inflammation in the pathogenesis of cardiomyopathy in this species.

Animals↗
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Molecular genetic basis of sudden cardiac death.

In this review, the up-to-date understanding of the molecular basis of disorders causing sudden death will be described. Two arrhythmic disorders causing sudden death have recently been well described at the molecular level, the long QT syndromes (LQTS) and Brugada syndrome, and in this article we will review the current scientific knowledge of each disease. A third disorder, hypertrophic cardiomyopathy (HCM), a myocardial disorder causing sudden death, has also been well studied. Finally, a disorder in which both myocardial abnormalities and rhythm abnormalities coexist, arrhythmogenic right ventricular dysplasia (ARVD) will also be described. The role of the pathologist in these studies will be highlighted.

Animals↗
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Risk factors for burns as a consequence of seizures in persons with epilepsy.

To explore the risk factors and circumstances for burns in a population of persons with epilepsy, we surveyed 244 University of Colorado Health Sciences Center Seizure Clinic patients. Twenty-five had at least one seizure-related burn requiring medical attention (12 were hospitalized), 21 reported burns requiring medical attention not related to seizure activity, and 199 reported no burns. All patients with seizure-related burns had alteration of consciousness during most seizures. Statistical models with logistic regression indicated that a useful model for assessing risk of seizure-related burns in this population of patients could be constructed using three significant variables; lifetime total number of seizures experienced by the patient, the presence of interictal neurologic impairment, and gender. The remainder of the variables studied (percentage of seizures that occurred nocturnally, percentage of seizures preceded by a simple partial seizure (SPS) warning, self-care status, number of seizures in adult life, seizure type, patient age, age of onset of seizure disorder, and presence of burns not associated with seizure) were either not significantly correlated with seizure-related burns or did not significantly improve the success of the statistical model in light of the other variables studied. Most injuries occurred in the home during activities that might have been avoided. They included 10 burns incurred while cooking, 5 incurred while showering (with a plumbing system that permitted exposure to scalding water), and 3 caused by exposed room heaters. A subset of epileptic patients are at increased risk for burns and should minimize situations in which they can be burned.

Accident Prevention↗
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Benign extra-axial collections of infancy.

The clinical histories, physical examinations and results of head computed tomography and head ultrasound scans were reviewed in a group of 15 infants who had macrocrania, excessive extra-axial fluid and normal development. Diagnostic evaluations demonstrated mild ventriculomegaly and extra-axial fluid collections. No treatment was undertaken. All infants continued to exhibit normal development during a period of extended follow-up. In this select group of infants exhibiting these findings, treatment appears to be unnecessary and the prognosis for continued normal development is excellent.

Brain↗
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Familial ventricular arrhythmias in boxers.

The purposes of this study were to evaluate families of Boxers with ventricular arrhythmias to determine whether this disorder is a familial trait and, if so, to determine the mode of inheritance. Eighty-two Boxers were evaluated by physical examination, electrocardiogram, echocardiogram, and 24-hour ambulatory electrocardiogram. Dogs were considered affected if at least 50 premature ventricular complexes (PVCs) were observed during a 24-hour period. All dogs were at least 6 years of age at evaluation. Complete cardiovascular examinations were performed on dogs from 6 extended families. The 2 most complete pedigrees were used to determine the pattern of inheritance. The number of PVCs observed during a 24-hour period in affected dogs ranged from 112 to 4,894 (mean +/- SD, median; 1,309 +/- 2,609, 1,017). The number of PVCs observed during a 24-hour period in the unaffected dogs ranged from 0 to 16 (7 +/- 10, 12). Pedigree evaluation was performed to determine pattern of inheritance. An autosomal dominant pattern was determined to be most likely because a sex predisposition was not observed, affected individuals were observed in every generation, and 2 affected individuals produced unaffected offspring. We conclude that familial ventricular arrhythmias is inherited as an autosomal dominant trait in some Boxers.

Animals↗
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Fatal Epstein-Barr virus myocarditis in a child with repetitive myocarditis.

Fatal Epstein-Barr virus (EBV) myocarditis occurred in a 9-year-old female with a history of two prior discrete episodes of myocarditis, the first associated with chicken pox and the second of undetermined origin. Serologic studies during the fatal episode were characteristic of acute EBV infection, and EBV genome was detected by polymerase chain reaction (PCR) amplification of DNA extracted from autopsy heart and liver. PCRs for enteroviruses and cardiac viral culture were negative. An intense mononuclear cell infiltrate in the myocardium consisted entirely of T cells, without identifiable B cells. Human leukocyte antigen HLA-DR analysis using frozen tissue obtained postmortem revealed antigens DR4 and DR13. DR4 is associated with some autoimmune disorders, as well as idiopathic dilated cardiomyopathy. We postulate that an aberrant immune response, possibly associated with the DR4 locus, was responsible for the repetitive episodes of myocarditis in this patient.

Acute Disease↗
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Neurologic complications of heart transplantation in children.

Neurologic complications can add significant morbidity to otherwise successful orthotopic heart transplantations in children. Complications have been reported to occur in up to 50% of children undergoing heart transplantation. The purpose of this study was to identify the prevalence and outcome of neurologic complications of heart transplantation in children. We reviewed all children who received orthotopic heart transplantation at Texas Children's Hospital from November 1984 to November 1990. Twenty-two patients (ages, 3 weeks to 17 years; mean, 8.5 years) underwent heart transplantation using cardiopulmonary bypass with moderate hypothermia. For analysis, we compared results during the first 3 years of our experience, 1984 through 1987 (group 1), to 1987 through 1990 (group 2). Survival was 45% (5 of 11 patients) for group 1 and 73% (8 of 11 patients) for group 2. A neurologic complication was defined as a change in the neurologic examination and/or status. Neurologic complications included seizures (6 of 22 patients), strokes (3 of 22 patients), unresponsiveness (3 of 22 patients), and change in mental status (2 of 22 patients). Early (within 2 weeks after operation) neurologic complications occurred in 45% (10 of 22 patients), were persistent (sequelae lasting more than 4 months) in 27% (6 of 22 patients), and resulted in death in 9% (2 of 22 patients). Late (after 2 weeks after operation) neurologic complications occurred in 23% (5 of 22 patients), were persistent in 9% (2 of 22 patients), and have occurred in only two survivors. Neurologic factors were not responsible for the cause of death in group 2. No neurologic complications (early or late) were seen in 1 of 11 patients in group 1 as compared with 7 of 11 patients in group 2 (p < 0.015). Serious neurologic morbidity decreased between the two groups after preoperative cyclosporine was avoided and postoperative hypertension was controlled. All survivors are functioning at age-appropriate levels. Although neurologic complications may be frequent, long-term neurologic disability in survivors is rare.

Adolescent↗
PubMedDate not supplied

Pseudoconduction of atrial flutter of a recipient atrium.

A nine-year-old girl had an episode of atrial flutter and a nonsustained wide QRS tachycardia during her initial hospitalization after orthotopic heart transplantation. Evaluation of her ECG and telemetric tracing revealed atrial flutter of the recipient atrium and sinus rhythm of the donor atrium. The wide QRS tachycardia was an accelerated ventricular rhythm that was also found on subsequent 24-hour ambulatory ECG monitoring. Timely recognition of recipient atrial arrhythmias prevents inappropriate clinical intervention.

Atrial Flutter↗