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Biomedical subjects

R L Hansen

Publications and source records attributed to R L Hansen.

16 recordsLinked to original sources
PubMed2001

Neuropeptides and neurotrophins in neonatal blood of children with autism or mental retardation.

There has been little exploration of major biologic regulators of cerebral development in autism. In archived neonatal blood of children with autistic spectrum disorders (n = 69), mental retardation without autism (n = 60), or cerebral palsy (CP, n = 63) and of control children (n = 54), we used recycling immunoaffinity chromatography to measure the neuropeptides substance P (SP), vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP), calcitonin gene-related peptide (CGRP), and the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4/5 (NT4/5). Neonatal concentrations of VIP, CGRP, BDNF, and NT4/5 were higher (ANOVA, all p values < 0.0001 by Scheffe test for pairwise differences) in children in the autistic spectrum and in those with mental retardation without autism than in control children. In 99% of children with autism and 97% with mental retardation, levels of at least one of these substances exceeded those of all control children. Concentrations were similar in subgroups of the autistic spectrum (core syndrome with or without mental retardation, other autistic spectrum disorders with or without mental retardation) and in the presence or absence of a history of regression. Among children with mental retardation, concentrations did not differ by severity or known cause (n = 11, including 4 with Down syndrome). Concentrations of measured substances were similar in children with CP as compared with control subjects. SP, PACAP, NGF, and NT3 were not different by diagnostic group. No measured analyte distinguished children with autism from children with mental retardation alone. In autism and in a heterogeneous group of disorders of cognitive function, overexpression of certain neuropeptides and neurotrophins was observed in peripheral blood drawn in the first days of life.

Autistic Disorder↗
PubMed1995

Lateral diffusion of molecules partitioned into C-18 ligands on silica surfaces.

Lateral diffusion rates of a fluorescent probe molecule partitioned into chromatographic C-18 ligands on a planar silica substrate were measured as a function of overlaying solvent composition. Diffusion coefficients of the probe were measured with a fluorescence recovery after patterned photobleaching experiment. A total internal reflection fluorescence flow cell held the derivatized planar substrate in contact with various aqueous solutions and allowed the fluorescence signal from two interfering, total internally reflected laser beams to be imaged onto a detector. Diffusion coefficients for the partitioned probe were approximately 3 orders of magnitude smaller than diffusion in solution and were found to increase with increasing methanol concentration in the overlaying aqueous solvent mixture. Inability of a solution phase ionic quencher to quench the fluorescence of sorbed rubrene confirmed that the probe is fully partitioned into the C-18 chains.

Chromatography↗
PubMed1993

Visual evoked potentials and visual processing in stimulant drug-exposed infants.

Prenatal exposure to cocaine and amphetamines has been associated with many adverse effects in infants, including neurological abnormalities. Recent evidence shows that the visual system may be useful in infancy to evaluate neurological functioning. Visual evoked potentials (VEPs) and visual recognition memory testing were carried out on eight infants with prenatal drug-exposure and eight controls, matched for ethnicity and socio-economic status. The drug-exposed infants performed significantly worse on the visual recognition test. However, there were no differences between groups on VEP testing and no correlations between tests. The results suggest that the difficulties found in visual recognition memory of drug-exposed infants are not related to neurological maturity, as measured by VEPs.

Amphetamines↗
PubMed1993

Research in pregnancy and mental illness: testing old wives' hypotheses.

Methodological challenges encountered in evaluating the relationships between life stress, mental illness and pregnancy outcome are identified and several studies on the relationships between pregnancy and childbirth and psychosocial factors, including life stresses, major psychiatric disorders, and puerperal depression, are reviewed. Certain methodological pitfalls are illustrated by showing how relationships between psychiatric diagnosis, severity of psychiatric symptomatology, life stresses, strains specific to the pregnancy, amount of intervention received and outcome of keeping or losing the infant have been explored. Five stages of research are identified and particular difficulties encountered at each stage are described with application to the authors' longitudinal study.

Female↗
PubMed1992

Visual recognition memory in drug-exposed infants.

Visual recognition memory testing in high-risk infants has been shown to have significant predictive ability for later cognitive deficits. This study evaluated cognition in infants exposed prenatally to illicit stimulant drugs compared with nonexposed controls with a standardized test of visual recognition, the Fagan Test of Infant Intelligence (FTII). Thirty-six healthy, full-term infants with prenatal exposure to cocaine and/or amphetamines and 26 infants with no drug exposures, matched for race and socioeconomic status, were tested. Average FTII scores were significantly lower and the percentage testing at risk significantly higher in the drug-exposed group (p less than .01). Differences between groups were also noted in behaviors dealing with attention, distractibility, and activity level. These data support recent evidence from longitudinal studies showing that infants exposed to drugs prenatally may be at risk for later subtle neurological abnormalities and suggest these difficulties may be identifiable long before the children reach school age.

Amphetamine↗
PubMed1992

Perinatal toxicology screening.

Accurate identification of substance abusing mothers and their infants is critical for appropriate medical management as well as the collection of accurate information on the effects of illicit drug use on perinatal morbidity, mortality, and long-term neurobehavioral outcome in the infants. This study examines the differences found using two methods for urine toxicology screening at the time of obstetrical admission to the hospital. The institution of universal screening identified significantly more women than were previously identified through the use of a risk-directed protocol (P less than .0001). Women identified using either protocol were significantly more likely than toxicology-negative women to have had poor prenatal care and to have smoked and used alcohol during pregnancy (P less than .001). In the population studied, the multiple criteria needed to accurately identify mothers with positive-toxicology screens would also include screening over one half of the toxicology-negative mothers.

Female↗
PubMed1991

Neonatal bilirubin exposure and psychoeducational outcome.

The association between neonatal bilirubin exposure and psychoeducational outcome was investigated in a group of grade school children 9 to 11 years old who required neonatal intensive care between 1977 and 1980. Seventy-four children were evaluated with four measures of psychoeducational outcome, including the Kaufman Mental Processing and Achievement Scales, the Beery Visual Motor Integration Test, and the Vineland Adaptive Behavior Scale. A measure of bilirubin binding calculated directly from the albumin concentration correlated significantly with the Kaufman Mental Processing Composite, although other more direct measures of bilirubin exposure (such as maximum serum bilirubin, direct measures of binding, and cumulative bilirubin exposure) did not. Thus, it is possible that the impact on psychoeducational outcome is the result of some other effect of low serum albumin itself, in addition to its ability to bind bilirubin. The correlation of the calculated albumin-determined binding value with the Kaufman Mental Processing Composite suggests that this level, rather than total serum bilirubin, may be more appropriate in determining clinical management.

Aptitude↗
PubMed1991

House dust mites in the West Indies.

The purpose of this study was to determine the role of the house dust mite. Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df), in allergic diseases on the island of St. Lucia. Dust samples were taken from living quarters of patients and hospital volunteers. The level of Df antigen in these living quarters was measured by RAST inhibition. All samples showed Df antigen within a large range of values. Prick tests were done to house dust mite and molds on 91 patients with suspected allergic disease with 63 (69%) reacting to at least one antigen. Of these, 56 (88.9%) reacted to one or both mites. House dust mite is a major allergen in St. Lucia.

Adolescent↗
PubMed1990

The perinatal impact of cocaine, amphetamine, and opiate use detected by universal intrapartum screening.

Universal urine testing for cocaine, amphetamines, and opiates was performed on 1643 women admitted to an obstetric service for a 1-year period with 20.5% having positive results. There were 299 patients with positive toxicology results matched for race and discharge date with patients having negative toxicology and drug history. Significant differences in age, prior obstetric history, prenatal care, alcohol history, and smoking were noted between groups. There was a significant decrease in birth weight, head circumference, length, and gestational age for the drug-positive group, which was most marked in cocaine and multiple drug users. These differences persisted after we controlled for smoking, prenatal care, and prior preterm births. Differences in birth weight and head circumference remained after we controlled for gestational age. Rates of congenital anomalies and abruptio placental were similar between groups. Perinatal substance abuse is independently associated with growth retardation and prematurity. Multiple risk factors are frequently present, necessitating a comprehensive approach to prenatal care.

Adult↗
PubMed1990

Diagnosis, treatment, and follow-up of newborns addicted to cocaine.

The Scientific Board of the California Medical Association presents the following inventory of items of progress in pediatrics. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and important clinical significance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, or scholars to stay abreast of these items of progress in pediatrics that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another. The items of progress listed below were selected by the Advisory Panel to the Section on Pediatrics of the California Medical Association, and the summaries were prepared under its direction.

Cocaine↗
PubMed1989

Effect of pregnancy on psychosis: life circumstances and psychiatric symptoms.

As part of an ongoing prospective study to correlate mother and infant outcome with social isolation during pregnancy, the Schedule for Affective Disorders, SADS-C, was administered to twenty-seven psychotic patients late in pregnancy. Extensive standardized evaluation of life stresses and social supports included a Prenatal Interview with sixty items relating to demographics, drug use, health and obstetrical history, family involvement and development expectations of the infant, and a thirty-item Difficult Life Circumstances questionnaire. In this sample the patients' previous life adjustments were stabilized by their pregnancy unless the pregnancy itself created personal stress for the patient. Higher scores on Difficult Life Circumstances were found to be associated with more psychiatric symptomatology. Symptoms of pregnancy confounded SADS-C items measuring vegetative signs of depression. One group of items on the SADS-C appeared to selectively identify a subset of women whose underlying affective symptomatology was potentiated by pregnancy. A second group of items identified women whose symptoms appeared to be reactive to current situational strains.

Adaptation, Psychological↗
PubMed1982

The effectiveness of visual information processing training with hispanic children.

The purpose of this study was to determine whether one kind of visual information processing training improves performance on visual tasks and on academic achievement. One hundred fifty-three kindergarten, first- and second-grade Hispanic children who were poor visual processors were randomly assigned to either a training, a contrast, or a control group. The training group received tutoring in visual-information processing for approximately seven weeks while the contrast group was given small group instruction with regular curriculum materials. At the conclusion of the training all Ss were administered several visual tasks and achievement measures. Results indicated that only the tutored children performed significantly better than the other children on the Bender Gestalt test and that the attained visual motor integrative skills were maintained over a period of time. However, training in visual processing skills did not increase performance on academic tasks or on a task of basic concepts.

Achievement↗
PubMed1977

Immunological studies on an aberrant form of ataxia telangiectasia.

We describe two brothers with ataxia telangiectasia (AT) of which one was unique in that he had no detectable IgG and IgA concentrations in the serum or saliva. The other brother had the more common IgA deficiency in the serum and saliva. Neither patient had a history of undue sinopulmonary infections. In spite of the absence of these immunoglobulins in the sera, there were cells in the bone marrow and peripheral blood that stained with fluorescein-labeled anti-IgG and anit-IgA. Both patients had demonstrable humoral antibody and cell-mediated immune responses to the antigens tested. We also discuss possible pathophysiological mechanisms causing the above defects.

Adult↗