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Biomedical subjects

M M Heitkemper

Publications and source records attributed to M M Heitkemper.

At least 19 recordsLinked to original sources

Gender differences and hormonal modulation in visceral pain.

Women seek healthcare and are diagnosed more frequently with chronic somatic and visceral pain conditions relative to men. These conditions tend not to be life-threatening disorders, but rather ones that decrease people's quality of life, impinge on work and recreational activities, and increase healthcare resource utilization. With increased awareness of basic gender differences in biology and responsiveness to therapies, there has been renewed interest in factors which may account for the gender disparity in chronic visceral pain conditions. Basic and clinical evidence primarily from patients with irritable bowel syndrome has provided initial insights into visceral pain sensitivity, perception, and responsitivity.

Autonomic Nervous System↗

Circadian rhythmicity of cortisol and body temperature: morningness-eveningness effects.

The purpose of this study was to describe and compare the circadian rhythm of body temperature and cortisol, as well as self-reported clock times of sleep onset and offset on weekdays and weekends in 19 healthy adult "larks" (morning chronotypes) and "owls" (evening chronotypes), defined by the Home and Ostberg questionnaire. Day-active subjects entered the General Clinical Research Center, where blood was sampled every 2 h over 38 h for later analysis for cortisol concentration by enzyme immunoassay. Rectal body temperature was measured continuously. Lights were turned off at 22:30 for sleep and turned on at 06:00, when subjects were awakened. The acrophases (peak times) of the cortisol and temperature rhythms occurred 55 minutes (P < or = .05) and 68 minutes (P < .01), respectively, earlier in the morningness group. The amplitude of the cortisol rhythm was lower in the eveningness than in the morningness group (P = n.s.). Subject groups differed on all indices of habitual and preferred timing of sleep and work weekdays and weekends (P = .05-.001).

Adult↗

Magnetic field goniometry: a new method to measure the frequency of stomach contractions.

A system of magnetic field goniometry was developed for measuring the frequency of stomach contractions. This technique uses a handheld, electronic compass to measure the angular change in direction of a magnetic field generated by a small, ingested magnet. Measurements of gastric mechanical activity made by goniometry were validated with simultaneous measurements using manometry and electrogastrography. The agreement between these different modalities was excellent. In this pilot study, magnetic field goniometry provided an easy, minimally invasive, and accurate method to measure the frequency of gastric contractions.

Adult↗

Feeding strategies for premature infants: randomized trial of gastrointestinal priming and tube-feeding method.

BACKGROUND: Data on enteral feeding management of premature infants are limited and often not the subject of randomized clinical trials. Several small studies suggest benefits from the early initiation of feeding, but do not assess the combined effects of time of initiation of feeding, tube-feeding method, and type of milk used. Either singly or in combination, these treatments may affect growth, bone mineralization, biochemical measures of nutritional status, and feeding tolerance, and, ultimately, the duration of hospitalization. METHODS: A total of 171 premature infants, stratified by gestational age (26 to 30 weeks) and diet (human milk or preterm formula) were assigned randomly among four treatment combinations in a balanced two-way design comparing the presence or absence of gastrointestinal (GI) priming for 10 days and continuous infusion versus intermittent bolus tube-feeding. RESULTS: The major outcome, time required for infants to attain full oral feeding, was similar among treatments. GI priming was not associated with any measured adverse effect and was associated with better calcium and phosphorus retention, higher serum calcium and alkaline phosphatase activity, and shorter intestinal transit times. The bolus tube-feeding method was associated with significantly less feeding intolerance and greater rate of weight gain than the continuous method. In addition, the greater the quantity of human milk fed, the lower the morbidity. CONCLUSIONS: Early GI priming with human milk, using the bolus tube-feeding method, may provide the best advantage for the premature infant.

Body Weight↗

Estrogen suppresses gastric motility response to thyrotropin-releasing hormone and stress in awake rats.

Symptoms associated with gastric motility alteration vary with stress and ovarian hormone status, most notably in women with irritable bowel syndrome. This study examines combined effects, comparing gastric motility during administration of a stress-related neuropeptide thyrotropin-releasing hormone (TRH) and restraint stress in conscious rats of varied ovarian hormone status. Adult rats were ovariectomized and implanted with estrogen, progesterone, or vehicle-releasing pellets. After 21 days, intracerebroventricular (i.c.) cannula and gastric tension transducer were implanted. After 25-27 days, motility was recorded during neuropeptide injection (TRH/saline i.c.) or restraint stress. TRH induced increased motility in all groups; the response varied with hormone group, and was least and briefest in estrogen-treated rats. Motility during restraint varied with hormone group; it was diminished in estrogen-treated but not other groups. Ovarian hormone status (estrogen) modifies gut response to TRH and restraint stress.

Animals↗

Sleep, psychological distress, and stress arousal in women with fibromyalgia.

The purpose of this investigation was to compare self-reported sleep quality and psychological distress, as well as somnographic sleep and physiological stress arousal, in women recruited from the community with self-reported medically diagnosed fibromyalgia (FM) to women without somatic symptoms. Eleven midlife women with FM, when compared to 11 asymptomatic women, reported poorer sleep quality and higher SCL-90 psychological distress scores. Women with FM also had more early night transitional sleep (stage 1) (p < 0.01), more sleep stage changes (p < 0.03) and a higher sleep fragmentation index (p < 0.03), but did not differ in alpha-EEG-NREM activity (a marker believed to accompany FM). No physiological stress arousal differences were evident. Less stable sleep in the early night supports a postulate that nighttime hormone (e.g., growth hormone) disturbance is an etiologic factor but, contrary to several literature assertions, alpha-EEG-NREM activity sleep does not appear to be a specific marker of FM. Further study of mechanisms is needed to guide treatment options.

Adult↗

Psychophysiological response to a laboratory challenge in women with and without diagnosed irritable bowel syndrome.

The purpose of this study was to describe and compare physiological variables at baseline and in response to laboratory stress among women diagnosed with irritable bowel syndrome (IBS, n = 26), women with undiagnosed chronic gastrointestinal symptoms consistent with IBS (IBS-NP, n = 24), and asymptomatic women (n = 22). Urine catecholamine levels were measured in the first voided specimen on the morning of testing. Cardiovascular variables were measured at baseline and repeatedly during the Stroop Color-Word Conflict Test (Stroop). Women in the IBS group had higher baseline systolic blood pressure (SBP) than the control group and higher basal urine norepinephrine (NE) levels than the IBS-NP group. Control for activity or body mass reduced the group difference in SBP to nonsignificance but did not affect the observed difference in urine NE. There were no significant differences among the groups in other baseline values or in response to the Stroop. These results suggest that, despite higher basal urine catecholamine levels, cardiovascular reactivity to a cognitive challenge in a laboratory setting is not elevated in women with diagnosed IBS.

Adult↗

The relationship between daily life stress and gastrointestinal symptoms in women with irritable bowel syndrome.

Research on irritable bowel syndrome (IBS), a functional disorder of the gastrointestinal (GI) system, has linked GI symptoms to stress. This study examined the relationship between daily stress and GI symptoms across women and within woman in IBS patients (n = 26), IBS nonpatients (IBS-NP; n = 23), and controls (n = 26), controlling for menstrual cycle phase. Women (ages 20-45) completed daily health diaries for two cycles in which they monitored daily GI symptoms and stress levels. The Life Event Survey (LES) was used as a retrospective measure of self-reported stress. The across-women analyses showed higher mean GI symptoms and stress in the IBS and IBS-NP groups relative to controls but no group differences in LES scores. The within-woman analyses found a significant and positive relationship between daily stress and daily symptoms in both the IBS-NP and the IBS groups. Controlling for menstrual cycle had no substantial impact on the results.

Adult↗

Daily gastrointestinal symptoms in women with and without a diagnosis of IBS.

This study compared daily gastrointestinal symptoms and stool characteristics across two menstrual cycles, and recalled bowel symptoms and psychological distress in women with irritable bowel syndrome (IBS, N = 22), IBS nonpatients (IBS-NP, N = 22), and controls (N = 25). Daily reports of abdominal pain, bloating, intestinal gas, constipation, and diarrhea did not differ significantly between the IBS and IBS-NP groups but both groups reported significantly higher symptoms than the control group. Stool consistencies was significantly looser in the IBS group relative to the control group. Menstrual cycle effects on symptoms were noted in all the groups. There were no significant differences in psychological distress between women with IBS and IBS-NP, but both groups reported significantly higher global distress than the control group. The lack of difference between the IBS and IBS-NP groups in contrast to the results of others, can be understood in terms of differences in recruitment strategies.

Abdominal Pain↗

Gastric motility in rats with varying ovarian hormone status.

Gastrointestinal (GI) symptoms suggestive of altered motility vary with menstrual cycle phase and menopause, but the effects of ovarian hormones on gastric motility have not been described. Basal and stimulated gastric motility were studied in male and female rats that were ovariectomized and implanted with continuous-release progesterone and/or estrogen pellets. Following 26 days of hormone treatment, rats were implanted with a gastric tension transducer. Contractile activity was recorded, then thyrotropin-releasing hormone (TRH) or saline was injected intracisternally and motility was monitored. An index was calculated based on frequency and amplitude; response to TRH was expressed as percentage of the basal index. Basal contraction frequency was highest in the estrogen and estrogen+progesterone groups. Hormone treatment significantly affected the TRH-stimulated motility index; TRH induced increased motility in all groups, with larger, more sustained responses in vehicle, progesterone, and male groups. Results demonstrate the ovarian hormone modulation of basal and stimulated gastric motility. Such modulation may contribute to changes in GI symptoms with altering ovarian hormone state.

Animals↗

Comparison of diet composition in women with and without functional bowel disorder.

Nurses are often involved in helping patients alleviate chronic distressing gastrointestinal symptoms such as those associated with irritable bowel syndrome or functional bowel disorder. One therapeutic strategy is to increase dietary fiber intake and to eliminate gastrointestinal (GI) irritants such as caffeine, alcohol, and tobacco smoking. However, little work has been done to establish a relationship between dietary factors and chronic GI symptoms. In this article, the authors: (a) describe and compare caloric and dietary constituent intake in symptomatic (n = 18) and asymptomatic (n = 37) women, and (b) examine the relationships among diet, GI symptoms, and stool characteristics in the two groups. In particular, total calories, fiber, fat, protein, and carbohydrates as well as alcohol and caffeine intakes were compared in women who do not smoke. Because menstrual cycle phase modulates both symptoms and appetite, women were studied during the follicular phase. Groups had similar caloric, fat, and protein intakes. Fiber intakes were similar and similar to national norms in both groups. When compared with asymptomatic women, the symptomatic women consumed more refined carbohydrates. Relationships were observed among dietary intake of refined carbohydrates, fiber, GI symptoms, and stool characteristics in women with functional bowel disorder.

Adult↗

Women with gastrointestinal symptoms: implications for nursing research and practice.

Irritable bowel syndrome and functional bowel disorder are diagnoses used to describe chronic GI symptoms for which no overt pathological condition can be identified. Symptoms are more common in women and are frequently followed in gastroenterology clinics. The purpose of this article is to provide an overview of the research linking GI symptoms and reproductive cycling and to discuss implications for practice. GI symptoms such as stomach pain and nausea are highest during menses compared with other cycle phases; also, stool consistency is loosest at menses. This pattern is present in control subjects. In women with irritable bowel syndrome the same pattern is seen but with higher symptom intensity. Although animal studies have demonstrated that estrogen and progesterone modulate contractile function of some GI segments, in humans, symptoms are highest when these hormones are at the lowest levels. Thus, symptoms in women may be related to decreasing ovarian hormone levels or to other circulating hormones or factors which vary with the menstrual cycle. Additionally, other factors such as stress aggravate symptoms. Therapeutics directed toward increasing patient awareness of cyclic patterns in symptom complaints, for example, via the use of daily symptom diaries may be a useful adjunct to dietary, pharmacological, and other therapies.

Autonomic Nervous System↗

Mediation of thyrotropin-releasing hormone induced gastric motility increases in developing rats.

Centrally administered thyrotropin-releasing hormone (TRH) induces vagally mediated gastrointestinal effects which may be cholinergic, serotonergic or a combination. This study investigated mediation of TRH-stimulated gastric motility in developing rats. A serotonin (5-HT) antagonist (5-HT2, ketanserin or xylamidine; 5-HT3, MDL 72222) or an acetylcholine receptor blocker (atropine) was administered intraperitoneally 30 min prior to intracisternal TRH (5-10 micrograms). The 5-HT-depleting para-chlorophenylalanine (p-CPA) was administered 48 or 72 h prior to TRH. Gastric motility, monitored via extraluminal strain gauge, was not increased with TRH in atropine-pretreated rats. MDL 72222 had a significant age-related effect on TRH-induced gastric motility increases while 5-HT2 antagonists and p-CPA treatment did not. Thus, acetylcholine receptor blockade inhibits TRH-stimulated gastric motility in young and adult rats while 5-HT3 antagonism eliminates the motility response in young (7 and 10 days) rats.

Aging↗

Pattern of gastrointestinal and somatic symptoms across the menstrual cycle.

The pattern of gastrointestinal symptoms and select mood and somatic symptoms was examined across two menstrual cycles in women with (n = 19) and without (n = 39) functional bowel distress (FBD). The women (a) rated their gastrointestinal, perimenstrual, mood, and other symptoms and stool frequency and consistency daily; (b) completed the Menstrual Distress Questionnaire-T; and (c) had serum levels of estrogen and progesterone measured during the menses, follicular, and luteal phases. Stomach pain, nausea, and diarrhea were rated higher at menses in the group with FBD than in the group without FBD. Stomach pain was higher during the remaining days as well. The group with FBD reported higher levels of perimenstrual symptoms also on six of the eight Menstrual Distress Questionnaire-T subscales (P less than 0.01). Other complaints, e.g., poor work/school performance, were higher in women with FBD, but somatic symptoms that were expected to vary over the cycle did not differ between groups, except cramping pain. There were no significant group differences in ovarian hormone levels or stool consistency/frequency scores.

Abdominal Pain↗

A possible 5-HT3 component of thyrotropin-releasing hormone-induced increases in gastric motility in developing rats.

Intracisternal injection of thyrotropin-releasing hormone (TRH) increases gastric motility primarily via a vagal cholinergic mechanism. However, a serotonergic (5-HT) component may also exist. Rats (7, 10, 14, and > or = 50 days of age) were anesthetized and gastric motility monitored via an extraluminal strain gauge. Following baseline, ICS 205-930 which blocks 5-HT3 and 5-HT4 receptors (0.01, 0.10, or 1.0 mg/kg) was administered intraperitoneally, then 30 min later intracisternal TRH (5 or 10 micrograms). ICS 205-930 0.1 and 1.0 mg/kg blocked TRH-induced motility in 7-day-old rats. Results support a 5-HT3 or 5-HT4 receptor contribution to TRH-induced gastric motility stimulation, and suggest that receptor expression is dynamic during development.

Animals↗

Morphine inhibits TRH-induced gastric contractile activity.

This study investigated the effect of centrally and peripherally administered thyrotropin releasing hormone (TRH) on gastric contractile activity of rats 14, 21, 28 and adult (greater than or equal to 50) days (D) of age, and the effect of morphine pretreatment on that response. Rats were anesthetized with urethane, then a tension transducer was implanted on the anterior gastric corpus. Following baseline recording, rats were pretreated with intraperitoneal morphine (2 mg/kg). TRH (5 micrograms) in saline or saline alone (0.6 microliters) was then injected into the cisternum magnum. Additionally, dose response to TRH was examined in 14- and 50-day-old rats. Intracisternal TRH induced a dose-related increase in gastric contractile activity in both 14- and 50-day-old rats. Higher doses of TRH (10 and 30 micrograms) prolonged the response as compared to low doses. Peripheral morphine pretreatment blocked the TRH-induced increase in gastric contractile activity in all age groups although a higher morphine dose (10 mg/kg) was needed to block the effect in 28D rats. Intravenous TRH (5, 10, 30 micrograms) produced an increase in gastric contractile activity in 14D rats which was blocked by vagotomy.

Animals↗