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C L Hanson

Publications and source records attributed to C L Hanson.

At least 19 recordsLinked to original sources
PubMed2001

Cyclic AMP- and IL6-signaling cross talk: comodulation of proliferation and apoptosis in the 7TD1 B cell hybridoma.

Proliferation of the 7TD1 B cell hybridoma is dependent on the survival factor interleukin-6 (IL6). IL6 inhibits physiological cell death and allows expansion of populations of serum-stimulated cells. In this report, we demonstrate that cyclic AMP (cAMP)- and IL6-dependent signaling pathways can interact, controlling proliferation of 7TD1 cells through modulation of apoptosis. Cyclic AMP analogues inhibited proliferation, as well as other treatments that increased intracellular cAMP. The cAMP-induced inhibition could be reversed after 24 h by the removal of dibutyryl-cAMP from the culture medium and readdition of IL6. In the absence of IL6, cAMP induced a slow loss of viable cells. This decrease in viable cells in the presence of cAMP was accompanied by a marked increase in apoptosis. The increase in apoptotic cells after 48 h was preceded at 24 h by a parallel increase in DEVD-caspase activity after treatment with cell-permeable cAMP analogues. Increased DEVD-caspase activity and subsequent apoptosis could both be blocked by the addition of IL6. These coregulating actions may represent a cross-talk signaling mechanism modulating cytokine activation of cellular proliferation and survival.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2000

Role of climbing fibers in determining the spatial patterns of activation in the cerebellar cortex to peripheral stimulation: an optical imaging study.

The spatial patterns of activation in the rat cerebellar cortex evoked by ipsilateral face stimulation were mapped using optical imaging based on the pH sensitive dye, Neutral Red. The aims of the study were to characterize the optical responses evoked by peripheral stimulation and test the hypothesis that the resultant parasagittal banding is due to climbing fiber activation. In the anesthetized rat Crus I and II of the cerebellar cortex were stained with Neutral Red. Epi-fluorescent changes produced by a train of stimuli (5-10s and 4-20 Hz) to the ipsilateral face were monitored in time using a fast, high resolution charge-coupled device camera. The patterns of activation were quantified using a two-dimensional fast Fourier transform analysis that removed signals with high spatial frequencies and minimized the contribution of horizontal structural elements (i.e. blood vessels). The dominant spatial pattern of activation evoked by face stimulation was that of parasagittal bands. The bands were highly frequency-dependent and were elicited most strongly by stimulus frequencies in the range of 6-8 Hz. There was a large fall-off in the response for frequencies above and below. The optical signal evoked by face stimulation built up over a period of 10s and then gradually decayed. Within a folium the individual parasagittal bands exhibited some frequency and temporal specificity. Stimulation of the contralateral inferior olive also resulted in the activation of parasagittal bands with characteristics similar to the bands evoked by face stimulation, including a preferred stimulus frequency which peaked at 10 Hz. Injection of lidocaine into the contralateral inferior olive blocked the parasagittal bands evoked by ipsilateral face stimulation, while control injections of saline had no effect. The results confirm that a parasagittal banding pattern is a dominant feature of the functional architecture of the cerebellar cortex. The parasagittal banding pattern observed with Neutral Red is due primarily to the activation of climbing fiber afferents. The frequency tuning of the responses, with the preference for peripheral stimuli of 6-8 Hz, is in agreement with previous findings that the inferior olive is inherently rhythmic. These observations support the hypothesis that inferior olivary neurons are dynamically coupled into groups that activate parasagittal bands of Purkinje cells in the cerebellar cortex. The frequency tuning also supports the hypothesis that the climbing fiber system is involved with timing. Activation of this afferent system may require stimuli with appropriate frequency content and stimuli synchronized to the rhythmicity of the inferior olive.

Action Potentials↗
PubMed1999

Novel form of spreading acidification and depression in the cerebellar cortex demonstrated by neutral red optical imaging.

A novel form of spreading acidification and depression in the rat cerebellar cortex was imaged in vivo using the pH-sensitive dye, Neutral red. Surface stimulation evoked an initial beam of increased fluorescence (i.e., decreased pH) that spread rostrally and caudally across the folium and into neighboring folia. A transient but marked suppression in the excitability of the parallel fiber-Purkinje cell circuitry accompanied the spread. Characteristics differentiating this phenomenon from the spreading depression of Leao include: high speed of propagation on the surface (average of 450 microm/s), stable extracellular DC potential, no change in blood vessel diameter, and repeatability at short intervals. This propagating acidification constitutes a previously unknown class of neuronal processing in the cerebellar cortex.

Acids↗
PubMed1998

Optical responses evoked by cerebellar surface stimulation in vivo using neutral red.

The pH sensitive dye, Neutral Red, was used with optical imaging techniques to map intracellular pH shifts elicited by cortical surface stimulation of the rat cerebellum. In the in vivo rat cerebellar cortex stained with Neutral Red, a brief stimulus train (three stimuli at 33 Hz) evoked a longitudinal beam of increased fluorescence (acidic shift) running parallel to the long axis of the folium within 100 ms of stimulation onset. A 5-10 s stimulus train (5-20 Hz) produced a biphasic optical response consisting of a beam of increased fluorescence (acidic shift) which returned to baseline in approximately 60 s, followed by a beam of decreased fluorescence (alkaline shift) for up to 120 s. A close spatial correspondence was observed between electrophysiological and optical maps of the response to surface stimulation. Application of acetazolamide enhanced the optical signals, acetabenzolamide-phenoxyethene had no effect, and the glutamate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, decreased the optical signals. Increased fluorescence was produced by superfusion of the cerebellar cortex with acidic Ringer solutions and a decrease in fluorescence by basic solutions. These fluorescence changes also occurred in the presence of several ion channel/receptor blockers. Increased fluorescence resulted from superfusion with Ringer solution containing sodium propionate and decreased fluorescence with the transition from 5% carbon dioxide to nominally carbon dioxide-free Ringer solution. Recovery from acid loading with ammonium chloride was prevented by amiloride, an inhibitor of the Na+/H+ transporter. Application of Ringer solution with high potassium concentration produced an increase in fluorescence but only a decrease in fluorescence was detected when neuronal blockers were present, an effect consistent with a glial contribution. This decrease in fluorescence was blocked by adding barium. No epifluorescent optical signals were obtained from unstained preparations or preparations stained with cell-permeant fluorescence markers, suggesting little contribution from activity-dependent volume changes and other intrinsic signals. These results demonstrate that the Neutral Red optical signals evoked by cerebellar surface stimulation are primarily pH based and include a significant component related to intracellular pH shifts. The large amplitudes of these optical signals are particularly useful for mapping neuronal activity. Furthermore, this technique provides a novel tool for the study of pH changes in vivo at both high spatial and temporal resolution.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1996

Self-care behaviors in insulin-dependent diabetes: evaluative tools and their associations with glycemic control.

Clarified the relationships between self-care behaviors and illness-specific outcomes in approximately 270 youths with IDDM. Youths were assessed at three points in time using a semistructured interview measure and multiple indices of dietary intake and physical activity with two different methodologies (i.e., recalls, logs). Glycemic control was most strongly related to the semistructured Self-Care Adherence Interview (SCAI); and second to the overall quality of the youth's dietary intake. The SCAI also predicted glycemic control over time. Physical activity levels and specific nutritional components from the logs and recalls were generally unrelated to glycemic control.

Adolescent↗
PubMed1996

Functional parasagittal compartments in the rat cerebellar cortex: an in vivo optical imaging study using neutral red.

1. The spatial patterns of activation in the rat cerebellar cortex evoked by peripheral stimulation were studied in vivo using optical imaging techniques. 2. Crus I and Crus II were stained with the pH sensitive dye, neutral red. Electrical stimulation of the vibrissae area of the ipsilateral face evoked optical responses consisting of parasagittal bands. The bands were 100-300 microns in width, elongated in the anterior-posterior direction, commonly extended across at least two folia, and varied in number from 1 to 7. 3. The optical responses were dependent on activation of postsynaptic elements since they were decreased substantially by the non-N-methyl-D-aspartate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione. The optical bands were shown to correspond anatomically with the parasagittal compartments revealed by immunostaining with anti-zebrin II. 4. The present study demonstrates that functional parasagittal compartments exist in the rat cerebellar cortex and suggests that zebrin-positive Purkinje cell subgroups are anatomically related to this functional organization.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1995

Empirical validation for a family-centered model of care.

OBJECTIVE: To examine whether family relations and family-life stress predict adherence behaviors and metabolic control in youths by testing a theoretically- and empirically-based model. RESEARCH DESIGN AND METHODS: HbA1c levels of 157 youths 12-20 years of age with insulin-dependent diabetes mellitus (IDDM) were evaluated, along with treatment adherence and psychosocial family data based on interviews and self-reports. A family-centered model for IDDM care was analyzed with the EQS structural modeling statistical program. An additional exploratory model including HbA1c levels 6 months earlier was also tested. RESULTS: Positive family relations (high family cohesion and low family conflict), especially during the first years of illness, indirectly related to good metabolic control through positive adherence behaviors. High levels of family-life stress related to worse metabolic control directly, and also indirectly via poor family relations, which in turn related to poor adherence to treatment. Longer illness duration related indirectly to metabolic control via adherence to treatment. Longer illness duration also related to maternal perceptions of higher family-life stress. Older youths perceived more family-life stress as well. The older age of the youths related indirectly to poor metabolic control through its association with poor adherence behaviors and less cohesive and more conflictual family relations. Results were consistent when earlier levels of metabolic control were included in the model, except that the direct relationship between family-life stress and metabolic control became nonsignificant. CONCLUSIONS: The findings suggest that a family-centered approach to diabetes care that facilitates positive family functioning and leads to lower levels of family-life stress may be useful in promoting optimal health outcomes.

Adolescent↗
PubMed1992

Contributions of sibling relations to the adaptation of youths with insulin-dependent diabetes mellitus.

Associations among sibling relations and the psychosocial and illness-specific adaptation of youths (N = 66) with insulin-dependent diabetes mellitus (IDDM) were examined. The findings suggest that sibling relations, especially sibling conflict, contribute an independent source of variance above and beyond that contributed by demographic characteristics, sibling constellation variables, and important dimensions of family relations in predicting the youths' adaptation. High family-life stress and high sibling status/power contributed unique variance in predicting internalizing behaviors, and male gender and sibling conflict contributed independently to externalizing problems. Sibling conflict also contributed unique variance to the youth's general self-esteem, along with social class and family cohesion, and to their adjustment to IDDM. Data suggest that parent-child dyads and sibling dyads represent interrelated and independent subsystems within the family, and that both subsystems may influence the psychosocial functioning of youths with IDDM.

Adaptation, Psychological↗
PubMed1992

Relationship between psychosocial functioning and body fat in preschool children: a longitudinal investigation.

This study examined whether preschool children differed on measures of psychosocial functioning both cross-sectionally and longitudinally. One hundred and thirty-two children who varied in levels of body fat participated in the study along with their natural parents. Results indicated that the children did not differ in levels of self-esteem and family functioning as a function of their body fat. Prospectively, physical self-esteem weakly (but significantly) correlated with body fat at 1 and 2 years, and father's perception of family functioning predicted body fat at 1 year only. Results suggested that childhood obesity may not develop as a result of psychosocial factors.

Adipose Tissue↗
PubMed1992

Comparing social learning and family systems correlates of adaptation in youths with IDDM.

Evaluated social learning and family systems theoretical models to determine (a) whether illness-specific family relations (based on social learning theory) and general family behaviors (based on family systems theory) relate uniquely to the youths' illness-specific and psychosocial adaptation, and (b) whether these types of family relations covary or whether they represent distinct aspects of family functioning. Participants included 95 youths with insulin-dependent diabetes mellitus (IDDM) and their parents. Positive and supportive family relations (illness-specific family support, general family affection, general family adaptability) as well as conflictual and nonsupportive relations (i.e., illness-specific family nonsupport, general family conflict) were assessed. Results suggest that both illness-specific and general family relations uniquely predict the youths' dietary adherence and general psychosocial adaptation. Because illness-specific and general family relations also covary, broad-based models that include both types of family functioning seem warranted.

Adaptation, Psychological↗
PubMed1992

Children at familial risk for obesity: an examination of dietary intake, physical activity and weight status.

A large cohort of children was divided into two groups based on their parents' weight status. The high risk group had one or two overweight parent(s) (n = 92, 4.4 +/- 0.5 years), while the low risk group had no parent overweight (n = 95, 4.5 +/- 0.5 years). Weight of the two groups was similar at the start of the study but the high risk group gained marginally more weight over a one year period (P = 0.05). Although total energy intake was similar, the high risk group was consuming a larger percentage of energy from fat (P = 0.0004) and a smaller percentage from carbohydrate (P = 0.0002). Observed physical activity as similar for most levels but marginally higher for the stationary level and marginally lower in total activity in the high risk group. These results suggest a pattern that may lead to increased weight gain in a high risk group as they grow older.

Adult↗
PubMed1991

Physical activity, body composition, and blood pressure: a multimethod approach.

The purpose of the current investigation was to evaluate, using multiple measures of physical activity, the relationships among physical activity, body composition, resting heart rate, and blood pressure in an adult population. Subjects were 221 male (135 normal weight, 86 overweight) and 221 female (156 normal weight, 65 overweight) subjects participating in a longitudinal study of cardiovascular risk factors in families. All subjects were administered three physical activity questionnaires. Principal components analyses were conducted to reduce measures into empirically derived subscales; this analysis revealed five stable factors in men and four in women. Results indicated that aerobic/leisure time significantly correlated to body composition and resting heart rate in both men and women. Additionally, aerobic/leisure time activity was related to blood pressure in women, and moderate activity was related positively to blood pressure in men. No other form of activity (e.g., light activity, anaerobic activity) was related to either adiposity or blood pressure. The implications of these results are discussed, and future research directions are highlighted.

Adult↗
PubMed1991

Measuring short-term dietary intake: development and testing of a 1-week food frequency questionnaire.

Measures typically used to assess short-term intake are 24-hour recalls or records of food intake. However, these methods require a large time commitment from both researchers and subjects. Our study sought to develop a more time-efficient method of assessing short-term intake by developing a 7-day food frequency questionnaire (7DFFQ). We modified Willett's 1-year food frequency questionnaire to assess intake for a 7-day period. Content validity has previously been exhibited in Willett's work. We assessed criterion validity by comparing the 7DFFQ with 24-hour recalls. Twenty-one female and 20 male college students were asked to recall their previous day's intake three times during a 1-week period. After the last recall, subjects completed a 7DFFQ covering the same week. Data were analyzed by comparing each recall and the mean of the three recalls with values obtained on the 7DFFQ. Analyses revealed high correlations between the mean of the three recalls and the 7DFFQ. Further analysis ranked subjects into quartiles for each nutrient on both measures. Most subjects changed either no quartiles or only one quartile for total energy and each nutrient. Test/retest reliability was assessed by administering the 7DFFQ to a group of women for two consecutive weeks and by administering the 7DFFQ to a group twice 3 hours apart. Pearson's r and intraclass correlations for the two administrations show moderately high reliability over the 1-week period and considerable improvement with the 3-hour administration. The 7DFFQ appears to meet several of the criteria for a measure of dietary intake.

Adolescent↗
PubMed1990

Effects of obesity, social interactions, and physical environment on physical activity in preschoolers.

Examined demographic, environmental, and parent-child interactional correlates of physical activity in a group of 222 preschoolers. Activity levels were assessed with a system that quantified directly observed physical activity in the natural environment. Using regression-modeling procedures, results revealed a significant relationship between (a) child's relative weight, parental weight status, and percentage of time spent outdoors (environment) and (b) children's activity levels. Parental obesity was associated with lower levels of physical activity in children, childhood relative weight was associated with slightly higher levels of physical activity, and more outdoor activity was associated with higher activity levels. Parental participation in children's activities also significantly interacted with levels of parental obesity in predicting activity levels. Those children with a 50% risk for obesity (as defined by both, one, or neither parent being overweight) had small changes in activity across levels of parent-child interaction, whereas those at higher risk for obesity responded with increased activity as parent-child interactions increased. Results are discussed, and the implications of these findings for future intervention efforts are examined.

Child, Preschool↗
PubMed1990

Smoking status: effects on the dietary intake, physical activity, and body fat of adult men.

This investigation evaluated the relationship between smoking status and body fatness, dietary intake, and physical activity in adults. Subjects were 210 males who were either regular cigarette smokers (n = 35) or nonsmokers (n = 175). Estimated body fat and waist-to-hip (girth) measurements were carefully obtained. Additionally, a sensitive assessment of long-term dietary intake and a multifactorial approach to the assessment of physical activity were made. Results indicated that smokers had lower estimated body fat as calculated by multiple skinfold thickness assessments. In contrast, smokers reported the same total energy intakes as nonsmokers and their levels of physical activity were significantly lower than those of nonsmokers. The differences in intake and expenditure in smokers and the role of metabolism as a possible determinant of the body fat differences in smokers vs nonsmokers are discussed.

Adult↗
PubMed1990

Peptic ulcer disease in youths with insulin-dependent diabetes mellitus: a prospective study.

Tested whether metabolic control, treatment variables, and psychosocial factors are associated with the onset of peptic ulcer disease (PUD) in 14 Ss with IDDM who later developed PUD and a matched group of 14 Ss who did not. Metabolic control was recorded 1 year before PUD diagnosis, at diagnosis, and 6 and 12 months after diagnosis. Treatment variables (adherence, insulin dose, number of injections, number of hospitalizations) and psychosocial factors (coping, stress, family relations) were assessed an average of 20 months prior to PUD diagnosis. A 2 (Group) x 4 (Time) repeated measures ANOVA revealed no between-groups differences on metabolic control. One-way ANOVAs indicated the groups did not differ on treatment variables or psychosocial factors, except that Ss in the PUD group reported more insulin injections. Research is needed regarding the correlates of PUD in Ss with well-controlled IDDM of relatively brief duration.

Adaptation, Psychological↗
PubMed1990

The perceived self-competence of adolescents with insulin-dependent diabetes mellitus: deficit or strength?

Two studies were conducted in an attempt to replicate an earlier finding of self-esteem deficits in adolescent girls with early onset of insulin-dependent diabetes mellitus (IDDM). Participants in Study 1 were 139 adolescents with IDDM who completed the Perceived Competence Scale for Children (Harter, 1979). A 2 (gender) X 2 (group: age of IDDM onset: early vs. late) multivariate analysis of variance (MANOVA) did not reveal a significant interaction effect. Study 2 included 136 adolescents (104 adolescents with IDDM and 32 physically healthy adolescents) who completed the Self-Perception Profile for Children (Harter, 1985). A 2 (gender) X 3 (early IDDM onset, late IDDM onset, physically healthy control) MANCOVA, controlling for the effects of social class and adolescent age, also indicated no significant interaction effect. Thus, we found no differences in self-esteem based on age at disease onset and gender in two independent samples of youths with IDDM. In Study 2, significant gender and group effects were revealed, but when these findings are compared with normative data and data from our physically healthy sample, the results suggest that the youths with IDDM were functioning within the normal range on self-esteem. The importance of these findings in regard to the deficit versus adaptation models of chronic illness is discussed.

Adaptation, Psychological↗