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Biomedical subjects

M Erickson

Publications and source records attributed to M Erickson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Feasibility of an implantable arrhythmia monitor.

Conventional Holter monitoring is of limited benefit in patients with infrequent symptoms suspected to be related to arrhythmia. A small recorder implanted subcutaneously might obviate many limitations of conventional monitoring. To determine the feasibility of obtaining adequate electrocardiographic signals from such a device, a prototype was temporarily implanted in 17 patients undergoing pacemaker implantation. The prototype contained four disc-shaped titanium electrodes, 0.21 inches in diameter embedded in epoxy. The four electrodes were in a square configuration spaced 0.72 inches center to center and were placed face down in a subcutaneous pocket in the left pectoral region. Bipolar recordings were made from a horizontal pair, a vertical pair, and both diagonal paris of electrodes (interelectrode distance 1.02 inches) and recorded on electromagnetic tape after filtering at 0.5-250 Hz. The mean peak-to-peak amplitude in each configuration was determined over a five-beat interval. Clear recordings were obtained from all 17 patients with recognizable P, QRS, and T waves. The amplitude of the signals obtained from the diagonal pairs of electrodes (175 +/- 51 and 170 +/- 54 microV) were greater than obtained from either the vertical pair (142 +/- 62 microV, P = 0.08 compared to diagonal electrodes) or the horizontal pair of electrodes (105 +/- 54 microV, P < 0.01). The maximum amplitude recorded from any configuration was 189 +/- 54 microV. In six patients the device was also tested with the electrodes face up in the subcutaneous pocket.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

An analysis of early intervention expenditures in Massachusetts.

Early intervention expenditure data from Massachusetts were linked to service data on a 157-member sample of Massachusetts early intervention service recipients. The findings revealed an enormous variability in the total expenditure per child estimate. Regression analyses identified specific child, family, and program characteristics that were significant predictors of the hours of service received. These results were then used to estimate expected hours of service and per child expenditures for eight subgroups. Variations in total expenditures by subgroup reflected differences in the distribution of service hours by service type. The implications of these findings for the implementation of Part H of P.L. 99-457 were discussed.

Child, Preschool↗
PubMed1992

Physiology of thirst and drinking: implication for nursing practice.

Thirst and drinking function to maintain body water balance and are basic to survival. Thirst is often associated with a dry unpleasant-tasting mouth and the feeling of a need to obtain water; it can result from dehydration, decreased vascular volume, dry mouth, pharmacologic agents, or inappropriate activation of the thirst mechanism. Drinking involves the motor activities that culminate in ingestion of liquids. Thirst sensation and drinking are influenced by many factors, including the temperature and taste of a liquid. Thirst may be discomforting in persons with limited fluid intake, diminished in some elderly persons, and inappropriate in persons who are compulsive water drinkers. Although nurses are commonly confronted with client complaints of thirst, there has been minimal nursing research that relates to assessment of thirst and drinking behaviors, nursing diagnoses for thirst, or nursing interventions for persons with altered thirst or drinking behaviors.

Compulsive Behavior↗
PubMed1990

Right ventricular pressure during ventricular arrhythmias in humans: potential implications for implantable antitachycardia devices.

Implantable defibrillators use algorithms based on ventricular electrographic data to detect the onset and termination of arrhythmias, but these algorithms do not always differentiate hemodynamically stable from unstable arrhythmias. Although, ideally, left ventricular function should be used to assess the hemodynamic state, right ventricular pulse pressure can be assessed in humans on a long-term basis with a transvenous lead. The potential utility of right ventricular pulse pressure to assess hemodynamic stability was studied in 22 patients with induced ventricular arrhythmias. Right ventricular pressure was measured with use of a transvenous right ventricular endocardial pacing lead with a piezoelectric bender pressure sensor 3 cm from its tip. Single ventricular premature paced beats administered in up to a bigeminal frequency did not alter the mean right ventricular pulse pressure (control 33.7 +/- 26, bigeminy 35.7 +/- 26 mm Hg). Twenty-one episodes of induced ventricular tachycardia were studied in the electrophysiology laboratory. Five seconds after tachycardia induction, hemodynamically stable ventricular tachycardia had a longer cycle length (294 +/- 41 ms) and the right ventricular pulse pressure ratio was higher (0.55 +/- 0.26) than that in unstable ventricular tachycardia (cycle length 256 +/- 55 ms, p = 0.06; pulse pressure ratio 0.26 +/- 0.09, p less than 0.05). Twenty episodes of ventricular fibrillation were induced in eight patients. One second after induction, right ventricular pulse pressure decreased from 25 +/- 5 to 6 +/- 3 mm Hg (p less than 0.05). On the first beat after defibrillation, right ventricular pulse pressure increased to 24 +/- 14 mm Hg, a level not significantly different from that before the induction of ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Caretaking burden and social support: comparison of mothers of infants with and without disabilities.

Data concerning mothers' perceptions of child caretaking burden, fathers' participation in child caretaking, and satisfaction with social support were analyzed for a 202 member sample consisting of mothers of infants with Down syndrome, motor impairment, developmental delay, and no known disabilities. The results were contrary to some common findings from the literature. Significant differences among the four groups were found on difficulty of and time devoted to caretaking, number of tasks with which fathers helped, and satisfaction with support from family, friends, and community groups. The programmatic and policy implications of these findings were discussed.

Developmental Disabilities↗
PubMed1988

Vitamin D metabolism, mineral homeostasis, and bone mineralization in term infants fed human milk, cow milk-based formula, or soy-based formula.

The purpose of this study was to evaluate mechanisms of mineral homeostasis and mineralization in term infants with recommended vitamin D intakes. Infants fed human milk (nine), cow milk-based formula (11), or soy-based formula (11) were studied at 2 weeks and at 2, 4, 6, 9, and 12 months of age. While receiving 400 IU of vitamin D, all infants maintained serum vitamin D concentrations higher or equal to normal adult concentrations, and serum 25-hydroxyvitamin D levels were maintained at or above normal adult levels. Serum 1,25-dihydroxyvitamin D concentrations were higher than those of adults in the formula-fed but not in the human milk-fed infants. Serum calcium and phosphorus values were similar in all groups; however, urine phosphorus excretion and urine calcium excretion were adjusted to intakes. Serum parathyroid hormone values were normal in all groups. Bone mineral content significantly increased with age similarly in all groups; however, an apparent plateau occurred at 6 months of age in all groups. Bone width steadily increased with age. Taken as a whole, these data suggest that the vitamin D-sufficient term infant fed human milk, cow milk-based formula, or the soy-based formula studied can regulate mineral metabolism within acceptable physiologic limits to attain similar levels of serum minerals and bone mineral content.

Alkaline Phosphatase↗
PubMed1986

Parents' and physicians' perceptions of facial plastic surgery in children with Down's syndrome.

This study was designed to investigate both parents' and physicians' attitudes and perceptions concerning facial plastic surgery in persons with Down's syndrome. The results of this inquiry revealed that more physicians (63%) than parents (28%) feel that the children's facial features negatively affect their social development; most parents (85%) see their children well accepted by society whereas only 4% of physicians do so; approximately half of the physicians (51%) and parents (41%) thought that after hypothetical facial plastic surgery a child with Down's syndrome may accomplish more socially; the majority of the parents (92%) and physicians (76%) were concerned with the risk of the operation; and only 13% of parents but 44% of physicians indicated that facial plastic surgery should be done on children with Down's syndrome.

Adaptation, Psychological↗
PubMed1984

Personal exposure to volatile organic compounds. I. Direct measurements in breathing-zone air, drinking water, food, and exhaled breath.

A pilot study to test methods of estimating personal exposures to toxic substances and corresponding body burdens was carried out between July and December 1980. Individual exposures to about a dozen volatile organic compounds in air and drinking water were measured for nine volunteers in Bayonne and Elizabeth, New Jersey, and for three volunteers in Research Triangle Park, North Carolina during three 3-day visits over the 6-month period. Breath samples were also collected from all subjects on each visit. Composite food samples were collected in each locality. Sampling and analytical methods for air, water, food, and breath were evaluated and found generally capable of detecting concentrations as low as 1 microgram/m3 in air and breath, and 1 ng/g in water and food. About 230 personal air samples, 170 drinking water samples, 66 breath samples, and 4 food samples (16 composites) were analyzed for the target chemicals. Ten compounds were present in air and eight were transmitted mainly through that medium. The two target trihalomethanes (chloroform and bromodichloromethane) were predominantly transmitted through water and beverages. Food appeared to be a minor route of exposure, except possibly for trichloroethylene in margarine. Seven compounds were present in more than half of the breath samples. Diurnal and seasonal variations were noted in air and water concentrations of some compounds, with summer levels generally higher. For some chemicals, weekday air exposures were significantly higher than weekend exposures. Some, but not all, of the potentially occupationally exposed individuals had significantly higher workplace exposures to several chemicals. Distributions of air exposures were closer to log normal than normal for most chemicals. Several chemicals were highly correlated with each other in personal air samples, indicating possible common sources of exposure.

Air Pollutants↗
PubMed1983

The developmental consequence of different patterns of maltreatment.

From a longitudinal study of 267 high risk families, four different patterns of maltreatment were identified. The mothers have been tested, interviewed and observed in a number of situations starting during the last trimester of pregnancy and continuing at regularly scheduled intervals through the preschool period. The four maltreatment groups were: physical abuse; hostile/verbally abusive; psychologically unavailable; and neglecting. A control group of mothers who provided adequate care was selected from the remaining high risk sample. In an earlier follow-up, among the maltreated children a disproportionately large number of infants were found to be anxiously attached to their mothers at 12 and 18 months, and their performance in a problem-solving situation at age two was poor. In the current follow-up, the children were videotaped at 42 months in a "barrier box" and teaching situation, and at 56 months they were observed in a preschool situation. The physically abused children were distractible, lacked persistence, ego control and enthusiasm, and experienced considerable negative emotion. The children whose mothers were psychologically unavailable showed marked increases in maladaptive patterns of functioning from infancy through preschool. As expected, they were avoidant of their mother, angry, noncompliant, and they were highly dependent. The neglected children had the most difficulty pulling themselves together to deal with various tasks. They lacked self-esteem and agency necessary to cope with their environment.

Adolescent↗
PubMed1982

Johns Hopkins University, Baltimore, Maryland.

The STEM can be used in one of three modes: 1) to image individual atoms; 2) to measure mass or molecular weight; 3) to collect electron energy loss spectra or x-ray fluorescence data. Heavy atom imaging is used to identify chemical groups in a molecule or macromolecules in an assembly. Specific labels have been developed for bases in nucleic acids. These permit localization of bound proteins on single strand nucleic acids. Pt(gly-L-met)Cl is a specific label for methionine residues of proteins as shown with the SLS aggregate of collagen. Lysine can be labeled as well if first methyl (methyl-thio-acetimidate) is coupled. This labeling procedure permits the localization of individual histones within a nucleosome. Mass determination can be used to answer crucial questions about biological assemblies. This is demonstrated by examples from muscle structure.

Amino Acids↗
PubMed1980

Serum 25-hydroxyvitamin D concentrations in sudden infant death syndrome.

Among the many theories put forth to explain sudden infant death syndrome (SIDS) is a theory of vitamin D deficiency. 25-Hydroxyvitamin D (25-OHD) serum concentrations were measured in 31 SIDS and 24 postmortem control infants. 25-OHD was 19.0 +/- 7.9 mg/ml in SIDS, 16.9 +/- 5.2 ng/ml in acute death control infants, and 11.9 +/- 4.4 ng/ml in in-hospital deaths. For four "near miss" infants the mean serum 25-OHD concentration was 21.1 +/- 4.1 ng/ml. The mean serum 25-OHD concentration of 39 living premature or small-for-gestational-age infants at 3 months of age was 26 +/- 9.9. Serum calcium and serum copper concentrations were also the same in SIDS and control infants. Parathyroid hormone was measured in ten and was detectable in five SIDS infants. These data eliminate a simple vitamin D deficiency or a 25-OHD deficiency as a significant contribution to the pathophysiology of SIDS.

25-Hydroxyvitamin D 2↗