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Biomedical subjects

A B Martin

Publications and source records attributed to A B Martin.

At least 19 recordsLinked to original sources
PubMed2006

Short birth intervals and the risk of school unreadiness among a Medicaid population in South Carolina.

BACKGROUND: Communities across the United States have become more involved in enhancing school readiness. Many of the predictors of school readiness relate to conditions prior to and following the birth of the child, including a child's birthweight. Shortened birth intervals are related to a variety of health and social consequences that affect child development, yet no formal research has examined the association between birth intervals and school readiness. METHODS: This study was a secondary data analysis of de-identified pregnancy-related vital record information, matched to selected items from the Department of Health and Human Services Medicaid records on mothers and children and to the Cognitive Skills Assessment Battery score in South Carolina for the year 2000 for the child of interest (N = 6915). Analysis of covariance and logistic regression were used to determine if there was a statistically significant relationship between birth interval and school readiness. RESULTS: Results showed that birth interval is a significant predictor of school readiness with a P-value <0.001 even after controlling for various socio-demographic factors. Children born with inadequate birth intervals (less than 24 months) are more likely to fail the Cognitive Skills Assessment Battery compared with those with adequate birth intervals. Potential implications of this research include promoting optimal birth spacing to improve the likelihood that future first graders will come to school ready to learn.

Adult↗
PubMed2003

Neuroanatomical relationship between type 1 cannabinoid receptors and dopaminergic systems in the rat basal ganglia.

Dopamine and endocannabinoids are neurotransmitters known to play a role in the activity of the basal ganglia motor circuit. While a number of studies have demonstrated functional interactions between type 1 cannabinoid (CB1) receptors and dopaminergic systems, we still lack detailed neuroanatomical evidence to explain their relationship. Single- and double-labeling methods (in situ hybridization and immunohistochemistry) were employed to determine both the expression and localization of CB1 receptors and tyrosine hydroxylase (TH) in the basal ganglia. In the striatum, we found an intense signal for CB1 receptor transcripts but low signal for CB1 receptor protein, whereas in the globus pallidus and substantia nigra we found the opposite; no hybridization signal but intense immunoreactivity. Consequently, CB1 receptors are synthesized in the striatum and mostly transported to its target areas. No co-expression or co-localization of CB1 receptors and TH was found. In the caudate-putamen, globus pallidus and substantia nigra, TH-immunoreactive fibers were interwoven with the CB1 receptor-immunoreactive neuropil and fibers. Our data suggest that the majority of the striatal CB1 receptors are located presynaptically on inhibitory GABAergic terminals, in a position to modulate neurotransmitter release and influence the activity of substantia nigra dopaminergic neurons. In turn, afferent dopaminergic fibers from the substantia nigra innervate CB1 receptor-expressing striatal neurons that are known to also express dopamine receptors. In conclusion, these data provide a neuroanatomical basis to explain functional interactions between endocannabinoid and dopaminergic systems in the basal ganglia.

Animals↗
PubMed2001

Trends in state health care expenditures and funding: 1980-1998.

Health care spending estimates constitute an important public policy tool, providing a broad look at historical trends in unique State health care systems. The State health expenditure estimates presented here detail spending for the 50 States and the District of Columbia for calendar years 1980-1998. They include expenditure estimates for specific service types as well as for two major sources of funding--Medicare and Medicaid. In this article, the authors address health care's role in State economies, trends in major service sectors and payers, and factors influencing these trends.

Financing, Government↗
PubMed2001

National health expenditures, 1999.

The health care spending share of gross domestic product (GDP) remained steady between 1993 and 1999 as moderate-to-strong economic growth coincided with a rapid shift to managed care. This shift, along with decelerating growth in Medicare spending, appears to have generated a mostly one-time saving that lowered aggregate health expenditure growth.

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PubMed2000

Single-molecule protein folding: diffusion fluorescence resonance energy transfer studies of the denaturation of chymotrypsin inhibitor 2.

We report single-molecule folding studies of a small, single-domain protein, chymotrypsin inhibitor 2 (CI2). CI2 is an excellent model system for protein folding studies and has been extensively studied, both experimentally (at the ensemble level) and theoretically. Conformationally assisted ligation methodology was used to synthesize the proteins and site-specifically label them with donor and acceptor dyes. Folded and denatured subpopulations were observed by fluorescence resonance energy transfer (FRET) measurements on freely diffusing single protein molecules. Properties of these subpopulations were directly monitored as a function of guanidinium chloride concentration. It is shown that new information about different aspects of the protein folding reaction can be extracted from such subpopulation properties. Shifts in the mean transfer efficiencies are discussed, FRET efficiency distributions are translated into potentials, and denaturation curves are directly plotted from the areas of the FRET peaks. Changes in stability caused by mutation also are measured by comparing pseudo wild-type CI2 with a destabilized mutant (K17G). Current limitations and future possibilities and prospects for single-pair FRET protein folding investigations are discussed.

Energy Transfer↗
PubMed2000

CT angiography of complications in pediatric patients treated with intravascular stents.

OBJECTIVE: Our goal was to determine whether CT angiography can reveal complications in pediatric patients and young adults treated with intravascular stents for obstructive vascular lesions. CONCLUSION: CT angiography can reveal complications in pediatric patients treated with intravascular stents for obstructive lesions. Potentially, CT angiography could replace the more invasive conventional angiography currently used for intravascular stent placement and follow-up examinations.

Adolescent↗
PubMed1999

Pulmonary stenosis: defect-specific diagnostic accuracy of heart murmurs in children.

OBJECTIVE: To determine the accuracy of expert examination for pulmonary stenosis (PS) among children with murmur. STUDY DESIGN: Five hundred twenty-one consecutive, previously unevaluated, pediatric patients were enrolled. The investigators prospectively recorded their diagnosis and level of confidence, categorizing any PS suspected as mild or severe. After echocardiography, PS was categorized by severity with peak systolic flow velocity. Receiver operating characteristic curves described accuracy of clinical examination. RESULTS: Sixty-two patients had PS (mild, 29; moderate, 27; and severe, 6). Receiver operator characteristic curve areas were: total, 0.834 +/- 0.033; mild, 0.862 +/- 0.044; and moderate to severe, 0.809 +/- 0.046 (P =.20). Specific difficulties in discrimination of PS from small ventricular septal defect, aortic valve disease, atrial septal defect, and innocent murmur were identified. All cases of severe PS in which PS was suspected were thought possibly severe. CONCLUSIONS: Although expert clinical examination is highly accurate for distinguishing PS from non-PS cardiac murmurs in pediatric patients, it is imperfect.

Adolescent↗
PubMed1999

Opportunities at the interface of chemistry and biology.

The combination of the tools and principles of chemistry, together with the tools of modern molecular biology, allow us to create complex synthetic and natural molecules, and processes with novel biological, chemical and physical properties. This article illustrates the tremendous opportunity that lies at this interface of chemistry and biology by describing a number of examples, ranging from efforts to expand the genetic code of living organisms to the use of combinatorial methods to generate biologically active synthetic molecules.

Antibodies, Catalytic↗
PubMed1999

National health expenditures, 1998.

In 1998, national health care expenditures reached $1.1 trillion, an increase of 5.6 percent from the previous year. This marked the fifth consecutive year of spending growth under 6 percent. Underlying the stability of the overall growth, major changes began taking place within the Nation's health care system. Public payers felt the initial effects of the Balanced Budget Act of 1997 (BBA), and private payers experienced increased health care costs and increased premium growth.

Budgets↗
PubMed1998

National health expenditures, 1997.

In 1997 health spending in the United States increased just 4.8 percent to $1.1 trillion. As a share of gross domestic product (GDP), national health expenditures (NHE) absorbed 13.5 percent of the country's output in 1997--a share that has remained relatively constant for 5 years. Despite the relative stability in recent years, signs of changing trends are emerging.

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PubMed1997

Children with heart murmurs: can ventricular septal defect be diagnosed reliably without an echocardiogram?

OBJECTIVES: This study was undertaken to determine the accuracy of expert examination for ventricular septal defect (VSD) among children with a heart murmur. BACKGROUND: Because the frequency and nature of errors that might be made by reliance solely on expert examination for diagnosis of VSD are speculative, the role of echocardiography in such diagnosis is controversial. METHODS: Two hundred eighty-seven consecutive previously unevaluated pediatric subjects were enrolled in the study. For each child, the pediatric cardiologists prospectively recorded a working diagnosis and their level of confidence in the diagnosis, categorizing any VSD diagnosed as small or moderate to large. After echocardiography, VSDs were subcategorized by location and requirement for treatment as minor, intermediate or major. Receiver-operating characteristic (ROC) curves described the accuracy of the clinical examination. RESULTS: Seventy-three subjects had a VSD (minor in 52, intermediate in 10 and major in 11). ROC areas (1.0 = perfect discrimination, 0.5 = indiscriminate) were minor VSD 0.92 +/- 0.02 and major/intermediate VSD 0.69 +/- 0.07 (p = 0.0016). Four of 52 minor VSDs were not identified at any level of suspicion; the clinical diagnoses were moderate to large VSD in two patients and atrial septal defect and unlimited differential diagnosis in one patient each. Fourteen of 235 patients without a minor VSD were believed with confidence to have a small VSD, but the final diagnosis was intermediate VSD in 4, innocent murmur in 3, major VSD in 2, pulmonary stenosis in 2 and subaortic membrane, atrial septal defect and mitral regurgitation in 1 patient each. CONCLUSIONS: Almost all minor VSDs are recognized without echocardiography; however, errors can occur even when an expert examiner is confident. Clinical recognition of an intermediate or major VSD is less accurate than clinical recognition of a minor VSD. Failure to distinguish VSDs of major or intermediate importance from minor VSDs is a weakness of the expert clinical examination.

Adolescent↗
PubMed1997

National health expenditures, 1996.

The national health expenditures (NHE) series presented in this report for 1960-96 provides a view of the economic history of health care in the United States through spending for health care services and the sources financing that care. In 1996 NHE topped $1 trillion. At the same time, spending grew at the slowest rate, 4.4 percent, ever recorded in the current series. For the first time, this article presents estimates of Medicare managed care payments by type of service, as well as nursing home and home health spending in hospital-based facilities.

Drug Prescriptions↗
PubMed1995

Postpericardiotomy syndrome in pediatric heart transplant recipients. Immunologic characteristics.

Clinical features of postpericardiotomy syndrome (PPS) occur in pediatric heart transplant recipients despite immunosuppression, which raises questions about the mechanism of PPS. We studied the clinical and immunologic characteristics of 15 pediatric heart transplant patients, ages 1.1 to 17.8 years (mean, 7.5 years); 7 had clinical evidence of PPS (PPS+), and 8 were without clinical features of PPS (PPS-). Indicators of PPS included fever, irritability, pericardial friction rub, leukocytosis without other cause, and pericardial effusion. The onset of PPS was from 9 to 26 postoperative days (mean, 16 days). Immunosuppressive regimens were comparable up to the day of PPS diagnosis in PPS+ patients, and up to day 16 in PPS- patients (average onset of PPS in PPS+ patients). No differences were found between groups with respect to weight-adjusted dosages of cyclosporin A, azathioprine, or corticosteroids. Mean cyclosporin A levels in PPS+ and PPS- patients were 142 +/- 88 ng/mL (mean +/- standard deviation) and 265 +/- 122 ng/mL (p = 0.045), respectively. Echocardiographic data on 3 PPS+ patients within 1 day of PPS diagnosis revealed pericardial effusions ranging from 5 to 24 mm. No data were available on the remaining 4 PPS+ patients. Minimal pericardial effusions (< 10 mm) were seen in 4 PPS- patients during a comparable time period. One PPS- patient required pericardiocentesis. Endomyocardial biopsy rejection grade did not differ between groups. Means pretransplant soluble interleukin-2 receptor levels did not differ between PPS+ and PPS- patients (758 +/- 410 vs 653 +/- 270 IU/mL); nor did the PPS+ pretransplant levels differ from levels obtained 1 or 2 months postoperatively (700 +/- 437 and 751 +/- 367 IU/mL, respectively). Although pretransplant percentages of the standard T-cell (CD2, CD3, CD4, CD8) and B-cell (DR and CD19) markers differed from post-transplant values, the changes could be explained by the immunosuppressive regimen and did not differ between PPS+ and PPS- patients. In the PPS+ patients, however, there were significant increases in the proportion of activated helper T cells (CD4+/25+) and cytotoxic T cells (Leu-7+/CD8+) following heart transplantation in comparison with pretransplant levels. We speculate that these changes in activation marker in PPS+ patients suggest a possible role for cell-mediated immunity in the pathogenesis of PPS in this group of patients.

Adolescent↗
PubMed1994

Prolonged QT interval in hypertrophic and dilated cardiomyopathy in children.

When the QT interval is prolonged in a patient with structural heart disease, there is a question of whether the QT interval prolongation is the result of coexistent long QT interval syndrome or ventricular hypertrophy. The purpose of this study was to assess whether QT interval prolongation can be attributed to ventricular hypertrophy/dilation alone. Electrocardiograms (ECGs) of 25 children in each of six echocardiographically proven groups (right ventricular hypertrophy, left ventricular hypertrophy, biventricular hypertrophy, hypertrophic cardiomyopathy, dilated cardiomyopathy, and normals) were analyzed. All patients had QRS interval durations < 100 msec, and patients with ventriculotomies were excluded. No patients in the normal group had a QTc interval > or = 0.45 sec. Eight (32%) of 25 patients with dilated cardiomyopathy had a QTc interval > or = 0.45 sec (p = 0.007 vs normal), 6 (24%) of 25 patients with hypertrophic cardiomyopathy had a QTc interval > or = 0.45 sec (p = 0.03 vs normal), and 2 of 25 patients each with right ventricular hypertrophy, left ventricular hypertrophy, and biventricular hypertrophy had a QTc interval > or = 0.45 sec (p = NS vs normal). There was no relation of the QTc interval to age, QRS duration, T-wave axis, or heart rate in any group. In the dilated cardiomyopathy group, there was no relationship of QTc interval to age, shortening fraction, or left ventricular end diastolic dimension. In conclusion, (1) a significant number of patients (24% to 32%) with dilated or hypertrophic cardiomyopathy may have a long QTc interval on the surface ECG, and (2) ventricular hypertrophy/dilation may be additional rare causes of acquired prolongation of the QT interval.

Adolescent↗
PubMed1994

Acute myocarditis. Rapid diagnosis by PCR in children.

BACKGROUND: The diagnosis of viral myocarditis remains difficult and generally depends on clinical and histological criteria. Viral cultures and serology are often unrewarding, with low yields. The purpose of this study was to analyze the usefulness of polymerase chain reaction (PCR) in the rapid diagnosis of acute myocarditis in children. METHODS AND RESULTS: PCR was used to analyze 38 myocardial tissue samples from 34 patients with suspected acute viral myocarditis and 17 control patients with congenital heart disease (14) or hypertrophic cardiomyopathy (3). Myocardial samples were obtained at the time of right ventricular biopsy (13 samples), from explanted hearts (18 samples) at transplantation, and from cardiac autopsy specimens (24 samples) and were evaluated for the presence of enterovirus, cytomegalovirus (CMV), adenovirus, and herpes simplex virus (HSV) using PCR primers designed to consensus and unique sequences of these viral genomes. Blood also was obtained at the time of biopsy (11) or transplant (18). In 26 of 38 myocardial samples (68%), viral genome was detected by PCR (15 adenoviral, 8 enteroviral, 2 HSV, 1 CMV), whereas all control myocardial samples and blood samples were negative. Four patients had positive viral cultures, and these matched the PCR findings. Disagreement with histopathology occurred in 13 of 26 PCR-positive specimens, usually associated with adenovirus. CONCLUSIONS: PCR offers a rapid, sensitive diagnostic method for myocardial viral infection. While enterovirus is an important etiological agent, adenovirus was more prevalent in this series and should be evaluated when etiology is sought. PCR used in conjunction with standard endomyocardial biopsy appears to enhance the likelihood of detecting viral genome in the myocardium of patients with clinical evidence of myocarditis.

Acute Disease↗