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Biomedical subjects

M Heitkemper

Publications and source records attributed to M Heitkemper.

At least 19 recordsLinked to original sources
PubMed2001

Autonomic nervous system function in women with irritable bowel syndrome.

Autonomic nervous system (ANS) balance was assessed in women with and without irritable bowel syndrome (IBS) using laboratory tests of function (ie, expiratory/inspiratory ratio, Valsalva, posture changes, and cold pressor) and spectral and nonspectral measures of heart rate variability (HRV). Women with (N = 103) and without IBS (N = 49) were recruited, interviewed, then completed a laboratory assessment and wore a 24-hr Holter monitor Analysis using the entire sample showed little difference between IBS and control women and between subgroups with IBS on either laboratory measures or 24-hr HRV measures. However, analysis restricted to those women with severe IBS symptoms showed quite pronounced differences between two IBS subgroups on 24-hr HRV measures. Parasympathetic tone was significantly lower and ANS balance was significantly higher in the constipation-predominant compared to the diarrhea-predominant group. Subgroups of women with IBS do differ in ANS function as measured by 24-hr HRV; however, these differences are only apparent among women with severe symptoms. These findings point out the importance of considering symptom severity when interpreting studies of IBS.

Adult↗
PubMed2000

Sleep disturbance influences gastrointestinal symptoms in women with irritable bowel syndrome.

This analysis evaluated the association between sleep disturbance and gastrointestinal symptoms in women with and without irritable bowel syndrome (IBS), and examined the role of psychological distress in this relationship. Women with IBS (N = 82) reported considerably higher levels of sleep disturbance compared to controls (N = 35), using both retrospective seven-day recall and daily diary recall for two menstrual cycles (P < 0.05 on 8 of 10 measures). We used daily diary data to estimate the association between sleep disturbance and gastrointestinal symptoms, both across women (ie, whether women with high average sleep disturbance have higher average gastrointestinal symptoms) and within woman (ie, whether poorer than average sleep on one night is associated with higher than average gastrointestinal symptoms the following day). The regression coefficients for the across-women effect are large and highly significant in both groups (IBS, beta +/- SE = 0.46 +/- 0.08, P < 0.001; controls, 0.57 +/- 0.13, P < 0.001). The regression coefficients for the within-woman effect are considerably smaller and statistically significant only in the IBS group (IBS, 0.06 +/- 0.02, P = 0.006; control, 0.01 +/- 0.03, P = 0.691). These regression coefficients showed little change when daily psychological distress or stress was controlled for, the one exception being the coefficient for the across-women effect in the IBS group, which decreased substantially but still remained highly significant. Because it is possible that gastrointestinal symptoms could, in fact, cause poor sleep, we also fitted the temporally reversed model to evaluate the association between gastrointestinal symptoms on one day and sleep disturbance that night. The within-woman regression coefficients were nonsignificant in both the IBS and control groups. In conclusion, these results are consistent with the hypothesis that poor sleep leads to higher gastrointestinal symptoms on the following day among women with IBS.

Adolescent↗
PubMed2000

Comparison of autonomic nervous system indices based on abdominal pain reports in women with irritable bowel syndrome.

Abdominal pain is an important symptom in irritable bowel syndrome (IBS), but patients report typical pain intensities ranging from mild to very severe. In a sample of women, the authors sought to determine whether measures of systemic autonomic activity are related to self-reported pain intensity and the occurrence of pain in the postprandial period. One hundred and six women with IBS and 41 controls completed bowel symptom and psychological distress questionnaires and wore 24-h Holter electrocardiogram monitors to estimate global heart rate variability measures of parasympathetic activity and sympathetic nervous system/parasympathetic nervous system balance. About one-third of the IBS sample reported severe or very severe abdominal pain (n = 34/106), and about one-half of the IBS sample reported postprandial pain (n = 52/106). Even after statistically controlling for age, body mass index, and psychological distress, vagal heart rate variability measures were markedly lower in women reporting high pain (P < 0.01) and markedly higher in women reporting postprandial pain (P < 0.02). The vagal component of heart rate variability appears to be reduced in women with severe abdominal pain, especially in those whose pain is not postprandial.

Abdominal Pain↗
PubMed1999

Effect of aerobic fitness on the physiological stress response in women.

Stress reactivity was assessed in aerobically fit (n = 14) and unfit (n = 8) females during the follicular phase of the menstrual cycle. Participants completed the Spielberger State-Trait Anxiety Inventory and provided a urine sample for catecholamine analysis before and after mental stress testing, Stroop Color-Word Test. Blood pressure, heart rate, muscle tension, and skin conductance were measured during mental stress testing. Fit and unfit participants differed significantly in baseline heart rate but not in stress reactivity or in state or trait anxiety. These data suggest that aerobic fitness does not attenuate the stress response in women prior to menopause.

Adult↗
PubMed1998

Luteal phase ovarian steroids, stress arousal, premenses perceived stress, and premenstrual symptoms.

The purpose of this study was to examine the relationships among perceived stress, ovarian steroids (estradiol and pregnanediol), stress arousal indicators (cortisol, catecholamines) and premenstrual symptoms (turmoil, fluid retention). Women (N = 74) with low symptom severity (LS), premenstrual syndrome (PMS), or premenstrual magnification (PMM) symptom patterns provided daily urine samples over one cycle and recorded their symptoms and perceived stress levels in a health diary. Multiple regression analysis was used to test models of premenstrual symptoms in separate analyses for women with the LS and PMS symptom patterns and the LS and PMM symptom patterns. Data from the LS and PMS groups revealed that greater stress ratings accounted for turmoil symptoms and higher luteal phase cortisol levels for fluid retention symptoms. For LS and PMM groups, lower luteal phase norepinephrine levels, higher global stress ratings, and a more gradual drop in estradiol premenses accounted for turmoil symptoms. Premenses norepinephrine and epinephrine levels and premenses stress ratings accounted for fluid retention. These findings support an important relationship among perceived stress, stress arousal indicators, and premenstrual symptoms that differs for women with a PMS and PMM symptom pattern.

Adult↗
PubMed1998

Perceived stress, physiologic stress arousal, and premenstrual symptoms: group differences and intra-individual patterns.

The purpose of this study was to examine evidence for perceived stress, hypothalamic-pituitary-adrenal, and autonomic nervous system involvement in premenstrual symptoms. Women with a low severity (LS, n = 40), premenstrual syndrome (PMS, n = 22), and premenstrual magnification symptom patterns (PMM, n = 26) rated perceived stress, turmoil, and fluid retention symptoms for one entire cycle. Daily late afternoon urine samples were assayed for epinephrine, norepinephrine, and cortisol. Using multivariate analysis of variance analyses, we found significant group and cycle phase and group by phase interaction effects for perceived stress. There were no group or cycle phase differences in cortisol, epinephrine, and norepinephrine. Intraindividual analyses using cross-correlation techniques revealed a positive time lagged relationship between perceived stress and norepinephrine and cortisol levels across all groups. Only women with a PMS pattern demonstrated perceived stress leading epinephrine levels. Cortisol, epinephrine, and norepinephrine levels led symptoms for all groups with one exception: there was no cross-correlation between epinephrine and turmoil for the PMS group. Perceived stress led both types of symptoms, regardless of group, and symptoms also led stress. The results provide evidence for a unique relationship between epinephrine, perceived stress, and symptoms for women with PMS, and for a reciprocal relationship between stress and symptoms for each of the groups.

Adult↗
PubMed1998

Early feeding, feeding tolerance, and lactase activity in preterm infants.

OBJECTIVE: We sought to ascertain whether the timing of feeding initiation affected the development of intestinal lactase activity and whether there are clinical ramifications of lower lactase activity. STUDY DESIGN: Preterm infants (26 to 30 weeks' gestation; n = 135) were randomly assigned to begin enteral feedings at either 4 (early group) or 15 days of age (standard group). At 10, 28, and 50 days of age lactase activity was determined by measuring the urinary ratio of lactulose/lactose after the 2 sugars were administered. RESULTS: Lactase activity increased significantly over time. Infants in the early group had greater lactase activity at 10 days of age (by 100%) and 28 days of age (by 60%) than the standard group. At 10 days of age lactase activity was greater in milk- versus formula-fed infants. The time required to achieve full enteral feedings, the number of abnormal abdominal x-ray examinations, and the total number of abdominal x-ray examinations were inversely related to lactase activity. CONCLUSIONS: Early feeding increases intestinal lactase activity in preterm infants. Lactase activity is a marker of intestinal maturity and may influence clinical outcomes. Whether the effects of milk on lactase activity were due to the greater concentration of lactose in human milk compared with that in formula must be determined.

Age Factors↗
PubMed1998

Evidence for autonomic nervous system imbalance in women with irritable bowel syndrome.

Autonomic nervous system function was assessed in women with and without irritable bowel syndrome using frequency domain measures of heart rate variability. Women were interviewed and placed into the irritable bowel syndrome (N = 25) group based on history of diagnosis and self-report of current gastrointestinal symptoms. Women in the control group denied a history of chronic gastrointestinal symptoms (N = 15). Women were followed for one menstrual cycle with a symptom diary, and during mid-luteal phase they wore a Holter 24-hr electrocardiograph monitor. Women with irritable bowel syndrome demonstrated significantly lower vagal tone as measured by the high frequency spectrum relative to control women. In addition, women with irritable bowel syndrome had a flattened 24-hr pattern of heart rate variability, with significantly lower levels of vagal tone during sleep. These results suggest that systemic sympathovagal balance may be shifted in a subset of women with irritable bowel syndrome.

Adult↗
PubMed1998

Early feeding, antenatal glucocorticoids, and human milk decrease intestinal permeability in preterm infants.

To determine the effects of age, feeding regimen, and antenatal glucocorticoids on intestinal permeability, preterm infants (n = 132) were stratified by gestational age and by diet (mothers' own milk versus preterm formula), and assigned randomly to one of four feeding regimens: early-continuous, early-bolus, standard-continuous, and standard-bolus. At 10, 28, and 50 d of age permeability was determined by measuring the ratio of lactulose/ mannitol in the urine after the two sugars were administered enterally for 30 h. The mean (+/-SE) birth weight and gestational age of the infants were 1044 +/- 13 g and 27 +/- 0.1 wk, respectively. Permeability changed as a function of age (p = 0.003). Early feeding was associated with a reduction in permeability at 10 d of age (p = 0.01). Antenatal steroid administration was associated with decreased permeability at 28 d of age (p = 0.017). The feeding of human milk (versus formula) was associated with decreased permeability at 28 d of age (p = 0.02). Continuous versus bolus feeding did not affect permeability.

Aging↗
PubMed1997

PMS after 40: persistence of a stress-related symptom pattern.

The purpose of this study was to compare women over 40 years of age with premenstrual syndrome (PMS) to women with a low-severity (LS) symptom pattern with respect to physiologic indicators of stress arousal and response, stress hormone arousal, stressful life circumstances, anger, self- and social control, and interpersonal sensitivity. Women with PMS experienced more negative life events, more difficulty with anger, and more concerns about self- and social control, than women with an LS pattern. These experiences were coupled with increased physiologic arousal and stress responses (skin conductance and muscle tension levels) and relatively higher norepinephrine levels than for women with an LS pattern, but with dampened cardiovascular responses to stressors. As they age, women with a PMS symptom pattern demonstrate persistent differences in stress arousal and response from women with an LS pattern.

Adult↗
PubMed1997

Research issues in nutrition support.

Nursing scientists have made important contributions to the understanding of individual responses to nutritional support as well as factors that place patients at risk for health complications. In addition, they have begun to incorporate measures of quality of life, function, and satisfaction into their outcome measures. This article focuses on describing the current state of nursing science related to nutrition support and issues related to the evaluation of research for implementation into practice.

Adaptation, Physiological↗
PubMed1996

Relationship between gastrointestinal and dysmenorrheic symptoms at menses.

The relationship between gastrointestinal (GI) symptoms and uterine cramping pain at menses, controlling for affective states and prostaglandin synthesis inhibitor use, was examined. A total of 53 women completed a daily diary of symptoms, stool characteristics, and medication use for three consecutive menstrual cycles. There were significant across-women and within-woman relationships between stomach pain, nausea, and uterine cramping pain, but not between cramping pain and constipation, diarrhea, or stool characteristics. These results support the presence of a similar mechanism in the generation of distressing GI symptoms and uterine cramping pain at menses.

Adult↗
PubMed1996

Increased urine catecholamines and cortisol in women with irritable bowel syndrome.

OBJECTIVES: There are few data on the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis in individuals with chronic GI symptoms. The current study was designed to describe and compare urine catecholamine (norepinephrine, epinephrine) and cortisol levels in women diagnosed with irritable bowel syndrome (IBS-patients), women who report similar symptom levels but had not sought health care services (IBS-nonpatients; IBS-NP), and asymptomatic (control) women. METHODS: Seventy-three women (24 IBS; 24 IBS-NP; 25 controls) were interviewed for demographic, GI, gynecological, and psychological data and then followed for two menstrual cycles with a daily health diary. Urine samples were obtained in the evening and morning at specific phases across two menstrual cycles. RESULTS: Women in the IBS group had significantly higher PM and AM urine norepinephrine levels. Urine epinephrine and cortisol levels were also generally higher in women with IBS. Differences in neuroendocrine indicators of arousal were not accounted for by differences in demographic variables, lifestyle characteristics, menstrual distress, or average daily measures of anxiety or depression. CONCLUSIONS: Increases in indicators of sympathetic nervous system activation in women seeking health care for IBS may reflect greater symptom distress or may contribute to increased symptom distress.

Adolescent↗
PubMed1995

TPN-induced sympathetic activation is related to diet, bacterial translocation, and an intravenous line.

OBJECTIVE: To investigate the effects of an intravenous line and the administration of a total parenteral nutrition (TPN) formula by the parenteral and oral routes on bacterial translocation and urinary catecholamine excretion in rodents. METHODS: Rats were fed chow with or without an intravenous line and a fat-free TPN solution either orally or intravenously for 5 consecutive days. Urine was collected on the first, third, and fifth days of feeding and quantitatively analyzed for norepinephrine and epinephrine excretion. Mesenteric lymph nodes were cultured for bacteria at the end of the study (day 5). RESULTS: Oral and intravenous TPN diets significantly increased norepinephrine excretion over time (P < .0001) compared with excretion in rats fed chow. Oral TPN diets increased epinephrine secretion after 5 days of feeding. The route of feeding TPN solution had no effect on norepinephrine or epinephrine excretion. Chow-fed rats with intravenous lines tended to have increased norepinephrine excretion over 5 days of feeding compared with chow-fed rats without intravenous lines (55% vs 13%, P = .08). Rats with bacterial translocation had greater norepinephrine excretion (mean +/- SEM, 136 +/- 23 pmol/mumol of creatinine) than rats without bacterial translocation (64 +/- 14 pmol/mumol of creatinine) (P < .05). CONCLUSIONS: Intravenous and oral fat-free, hypertonic glucose diets increase sympathetic nervous activity. This diet-induced sympathetic activity may be related to the presence of an intravenous line, bacterial translocation, the thermic effects of hypertonic glucose, and/or the absence of orally ingested food substances in rodent chow. In this model of rodent feeding, increased sympathetic activity may account for alterations in intestinal and immunologic defenses.

Administration, Oral↗
PubMed1995

Polymyxin B prevents increased sympathetic activity and alveolar macrophage tumor necrosis factor release in parenterally fed rats.

OBJECTIVE: To determine the effects of polymyxin B sulfate in rats fed by total parenteral nutrition on norepinephrine excretion, macrophage tumor necrosis factor production, and bacterial translocation. DESIGN: Randomized animal study. SETTING: A university teaching hospital in Seattle, Wash. MATERIALS AND METHODS: Three groups of rats were studied: chow plus intravenous saline, total parenteral nutrition, or total parenteral nutrition supplemented with polymyxin B sulfate. After 5 days, urinary excretion of norepinephrine and epinephrine was calculated, peritoneal and alveolar macrophages were cultured, and their spontaneous and lipopolysaccharide-stimulated tumor necrosis factor production was measured. Mesenteric lymph nodes were cultured for bacteria. RESULTS: Rats fed by total parenteral nutrition had increased urine norepinephrine excretion (33%) and alveolar macrophage tumor necrosis factor production (80%) and trends for increased epinephrine excretion and bacterial translocation compared with rats fed chow. Alveolar but not peritoneal macrophage tumor necrosis factor production was significantly related to norepinephrine excretion (r = .5, P < .01). The addition of polymyxin B to total parenteral nutrition decreased weight gain (P < .05), urinary norepinephrine excretion (P < .01), and alveolar macrophage tumor necrosis factor production (P < .05) compared with rats fed by total parenteral nutrition. Polymyxin B also tended to decrease the magnitude of bacterial translocation. CONCLUSIONS: Alveolar macrophage tumor necrosis factor production appears to be influenced by sympathetic nervous activity. Total parenteral nutrition-induced endotoxemia may indirectly alter macrophage function by stimulating sympathetic nervous activity.

Animals↗
PubMed1990

Thyrotropin-releasing hormone stimulates intestinal transit in young rats.

The effect of intracisternal injection of thyrotropin-releasing hormone (TRH) on small intestinal transit of a charcoal bolus was investigated in 14-, 21-, 28- and 35-day-old and adult rats. Intracisternal TRH (15 micrograms in 2 microliters) was administered, and transit (distance traveled by the charcoal) was measured 120 min later. In all age groups, intracisternal TRH increased charcoal transit significantly (P less than 0.05) as compared to saline-treated controls. This increase in transit was not mimicked by intravascular TRH, and it was blocked in all age groups by prior intraperitoneal injection of atropine (2 micrograms/g body weight). Vagotomy blocked TRH-induced increases in small intestine transit in rats of 28 days and older. Prior intraperitoneal injection of the antiserotonin compound, cyproheptadine (1 microgram/g body weight) reduced TRH-induced increases in small intestine transit in all age groups. These results demonstrate that centrally administered TRH stimulates small intestine transit through both cholinergic and serotonergic mechanisms in rats as early as 14 days of age.

Age Factors↗