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Biomedical subjects

L C Jones

Publications and source records attributed to L C Jones.

17 recordsLinked to original sources
PubMed1992

Evaluation of marrow perfusion in the femoral head by dynamic magnetic resonance imaging. Effect of venous occlusion in a dog model.

RATIONALE AND OBJECTIVES: There is a continuing need for a greater sensitivity of magnetic resonance imaging (MRI) in the diagnosis of avascular necrosis (AVN). Previously, it was demonstrated that a dynamic MRI method, with gadolinium-DTPA (Gd-DTPA) enhancement, can detect acute changes not seen on spin-echo images after arterial occlusion in a dog model. Because venous congestion appears to be a more directly relevant hemodynamic abnormality in a majority of clinical AVN cases, the authors extended the dynamic MRI technique to study changes in venous occlusion. METHODS: Dynamic MRI of the proximal femur was performed in five adult dogs before and after unilateral ligation of common iliac and lateral circumflex veins. Sixteen sequential gradient-recalled pulse sequence (GRASS) images (time resolution = 45 mseconds, echo time = 9 mseconds, flip angle = 65 degrees) were obtained immediately after a bolus intravenous injection of 0.2 mmol/kg of Gd-DTPA. Simultaneous measurements of regional blood flow were made using the radioactive microsphere method. RESULTS: After venous ligation, there was a 25% to 45% decrease in the degree of enhancement compared with preligation values on the ligated side. The decrease in cumulative enhancement (integrated over the entire time course) was statistically significant. The occlusion technique was verified by confirming a statistically significant decrease in blood flow determined by the microsphere method. CONCLUSIONS: Dynamic Gd-DTPA-enhanced fast MRI technique can detect acute changes in bone marrow perfusion due to venous occlusion. This technique may have applications in the early detection of nontraumatic AVN.

Animals↗
PubMed1992

Multi-frequency bioelectrical impedance augments the diagnosis and management of lymphoedema in post-mastectomy patients.

The value of multiple frequency bioelectric impedence analysis (MFBIA) in the monitoring and management of post-mastectomy lymphoedema of the arm was evaluated in 15 patients and controls. The technique was found to produce quantitative agreement with a clinical diagnosis of lymphoedema and with the currently-used measure (limb volume calculated from circumferential measurements) of limb size. The significance of this finding lies in MFBIA being diagnostically informative: it indicates when an observed change in limb volume is directly, albeit theoretically, attributable to accumulation of extracellular fluid. MFBIA potentially offers the means for earlier definitive diagnosis and more-accurate monitoring of extracellular fluid changes during and after treatment.

Adult↗
PubMed1991

Families of children with developmental disabilities: an examination of family hardiness.

Using the Typology Model of Adjustment and Adaptation, a family stress model, relationships among family hardiness, family stressors, family appraisal, coping, social support, and satisfaction with family functioning were examined in a sample of 57 families of children with developmental disabilities. Family hardiness was associated with family appraisal, social support, parental coping related to maintaining family integration, and satisfaction with family functioning. Higher satisfaction with family functioning was correlated with coping-integration, network support, functional support, and hardiness. Lower satisfaction with family functioning was associated with higher family stressor scores, social support loss, and increased parental age. Over 42% of the variance in family functioning was accounted for by family hardiness, functional support, family stressors, and parental age. The results highlight the value of continued investigations of hardiness in families.

Adaptation, Psychological↗
PubMed1991

Bone marrow perfusion evaluated with gadolinium-enhanced dynamic fast MR imaging in a dog model.

The authors studied, in a dog model, the feasibility of using gadolinium-enhanced dynamic magnetic resonance (MR) imaging to noninvasively monitor bone marrow perfusion of the proximal femur. With a gradient-recalled acquisition, sequential images of 10 hips in five healthy dogs were obtained for 14 minutes after an intravenous bolus injection of 0.2 mmol of gadopentetate dimeglumine per kilogram. The study was repeated after unilateral arterial embolization of major femoral vessels. Radiolabeled microspheres were injected before and after vessel occlusion. After unilateral embolization, statistically significant differences in enhancement were observed between embolized and control sides (eg, 31% vs 83% average peak enhancement in the femoral neck). There was a high correlation (r = .81 [average]) between the MR data and the microsphere blood flow measurements. The postembolization data indicate that contrast-enhanced fast MR imaging may allow early detection of abnormal bone marrow flow. This technique may be valuable in evaluating patients at risk for avascular necrosis of the femoral head, especially in posttraumatic cases.

Animals↗
PubMed1990

Sex differences in voluntary locomotor activity of food-restricted and ad libitum-fed rats. Implications for the maintenance of a body weight set-point.

1. Male and female Wistar-strain rats were studied under either ad libitum or 23-hour food restriction conditions both with and without access to a running wheel. 2. Daily measures were taken of body weight, food consumption and wheel revolutions. 3. It was observed that food restriction was associated with decreased food consumption and body weight but increased wheel revolutions. 4. Irrespective of feeding regime, females exhibited higher running rates than males.

Animals↗
PubMed1990

Frequency of illness in mother-infant dyads.

The purpose of this study was to identify the frequency and types of illnesses experienced by mothers and their infants who were in the second half of the first year of life, the actions taken concerning these illnesses, the number of days the mother was hospitalized or in bed because of illness, and the subjective health status of both as rated by the mothers. During home visits mothers (N = 182) completed the Health Status Interview. They were asked about infant and maternal illness in the previous month and the actions taken in response to them. The number and types of illnesses reported indicate that mothers of full-term infants who were healthy at birth must deal with a number of minor illnesses in themselves and in their infants. The possible relationship of maternal illness to stress is discussed and suggestions are given for interventions by health professionals.

Adult↗
PubMed1989

Chronic ingestion of ethanol increases stimulation-induced voluntary activity in the rat.

Acute exposure of an animal to ethanol has a biphasic effect on activity; at low doses incurring stimulation of locomotor activity whilst at higher doses eliciting a depression in activity level. The present study reports the effect of short-term (10 days) exposure to ethanol on running wheel activity in female Wistar rats. Ethanol treatment (3 g/100 ml in drinking water) increased significantly the rate of accumulation of total distance run but not the daily rate of running when compared to control animals. This increase was attributable to an increased rate of running stimulated by daily feeding and handling by the experimenter.

Alcoholism↗
PubMed1988

Clinical experience with a triradiate exposure of the hip for difficult total hip arthroplasty.

A triradiate exposure of the hip was developed to facilitate the performance of certain difficult primary and revision total hip arthroplasties. Using this triradiate skin and fascial incision, complete anterior and posterior exposure of the hip capsule can be performed with relative ease. Between October 1980 and January 1985, this exposure was used 50 times in selected cases, including 9 of 320 (3%) primary total hip arthroplasties. All of these cases involved obesity, acetabular protrusion, and/or fragile femoral bone, conditions that would have made safe, adequate exposure without trochanteric osteotomy considerably more difficult through a routine anterolateral or posterior approach. Over this period, the majority of revision hip arthroplasties were performed using triradiate exposure; trochanteric osteotomy was routinely performed in these revision cases. Excellent wound healing was observed in every case, despite unfavorable factors such as advanced age, prednisone therapy, and the presence of prior incisional scars. The triradiate incision offers safe, controlled, and improved exposure in selected primary and revision total hip arthroplasties. It has become nearly the routine incision for the senior author for revision cases.

Aged↗
PubMedDate not supplied

Nurse practitioners: leadership behaviors and organizational climate.

The purpose of this article is to examine the relationships of individual nurse practitioners' perceptions of the leadership climate in their organizations and self-reported formal and informal leadership behaviors. The nine climate dimensions (Structure, Responsibility, Reward, Perceived Support of Risk Taking, Warmth, Support, Standard Setting, Conflict, and Identity) identified by Litwin and Stringer in 1968 were used to predict five leadership dimensions (Meeting Organizational Needs, Managing Resources, Leadership Competence, Task Accomplishment, and Communications). Demographic variables of age, educational level, and percent of time spent performing administrative functions were forced as a first step in each multiple regression analysis and used to explain a significant amount of variance in all but one analysis. All leadership dimensions were predicted by at least one organizational climate dimension: (1) Meeting Organizational Needs by Risk and Reward; (2) Managing Resources by Risk and Structure; (3) Leadership Competence by Risk and Standards; (4) Task Accomplishment by Structure, Risk, and Standards; and (5) Communication by Rewards.

Adult↗
PubMedDate not supplied

Differentiation of self and attachment among adult daughters.

The relation among the variables differentiation of self, attachment to mother, and two indicators of mental health were studied in 83 nonclinical adult daughters from a Southern community. An a priori causal model was proposed and tested. Bowen's (1976) theory of differentiation of self and Bowlby's (1969) attachment theory provided the conceptual framework. An operational Daughter Model was tested using the statistical program LISREL. Compared to mothers, daughters scored significantly lower on differentiation of self. Daughter's attachment to mother and daughter's level of self-differentiation were not causally related, supporting the view that differentiation of self and attachment are separate variables in personality development. The daughters' levels of differentiation of self were positively related to positive energy, thus supporting Bowen's theory. These findings affirm the value of attachment behaviors and differentiation of self in adulthood, challenge therapists' bias against attachment behaviors of women, and provide a focus for mental health promotion among women.

Adult↗
PubMedDate not supplied

Research application: teaching staff nurses to use library search strategies.

Journal reading is a major mechanism for disseminating research but much goes unread by practicing nurses. A survey revealed the 10 most frequently read journals are primarily of a clinical/technical nature. To encourage reading of research, we organized a series of library sessions to familiarize nurses with the library and modern search strategies. Over half of the 77 nurse participants indicated they had not visited the library in six months and were less than confident in their library skills. Hands-on experiences, including computerized literature search, gave nurses an opportunity to learn techniques for locating research articles.

Education, Nursing, Continuing↗
PubMedDate not supplied

Parental division of infant care: contextual influences and infant characteristics.

The purpose of this study was to explore the relationship of maternal employment to division of parental infant caregiving and whether infant characteristics predicted maternal and paternal caregiving during the first year. Subjects were 351 families with healthy infants from normal pregnancies. Measures included a newborn and 1-month Brazelton Neonatal Behavioral Assessment, Child Care Activities Scale at 1, 6, and 12 months, Bates Infant Characteristics Questionnaire at 6 and 12 months, and selected demographics. Mothers provided the majority of infant care though fathers' proportion increased with employment of mothers. Controlling for demographics, infant characteristics were infrequent predictors of maternal caregiving and predicted a small amount of paternal caregiving variance.

Adult↗
PubMedDate not supplied

New fathers' blood pressure and heart rate: relationships to interaction with their newborn infants.

Cardiovascular changes in 148 first-time fathers while holding and interacting with their newborn infants are described and relationships of fathers' verbal and nonverbal behavior with these cardiovascular changes are discussed. Systolic and diastolic blood pressure (SBP, DBP) and heart rate (HR) were monitored before, during, and after interaction with the infants in a controlled hospital setting using a noninvasive oscillometric monitor. Subjects were videotaped during the interaction period. Analyses of cardiovascular responses controlled for preinteraction values revealed that all measures were significantly higher during interaction than during the postinteraction period. The frequency of fathers' verbal behaviors was negatively related to SBP and positively related to HR during interaction. Frequency of infant crying was positively related to fathers' DBP both during interaction and in the postinteraction period. Fathers appeared highly sensitive to the stimuli of interacting with their newborns and responded in a complex manner to infant signals. The findings may indicate an autonomic balance that is situationally specific.

Adolescent↗