Biomedical subjects

Paul Enck

Publications and source records attributed to Paul Enck.

At least 19 recordsLinked to original sources

PubMed2007

Asymmetric sphincter innervation is associated with fecal incontinence after anal sphincter trauma during childbirth.

AIMS: Functional asymmetry of pelvic floor innervation has been shown to exist in healthy subjects, and has been proposed to be a predictor of increased risk for fecal incontinence in case of trauma. However, this remains to be shown for different clinical conditions such as traumatic childbirth. METHODS: A conventional surface EMG system was used to assess the innervation of the external anal sphincter. A symmetry index was used to define the relative EMG amplitude asymmetry of the external anal sphincter between 0 (symmetric) and 1 (asymmetric). Three cohorts were studied: 40 nulliparous women in the third trimester (Study 1), 15 primiparous women within 6 months following vaginal delivery without clinically apparent anal sphincter trauma (Study 2), and 50 women after childbirth-related third or fourth degree perineal tear 6-12 months postpartum (Study 3). Furthermore, all women underwent conventional anorectal manometry. RESULTS: Sixteen or forty nulliparous women reported signs of fecal incontinence; however, relative asymmetry was not correlated to symptom severity (P = 0.345), and not to manometric measures (Study 1). In Study 2, Women who had suffered clinically apparent anal sphincter trauma (P = 0.07) tended to have a stronger association between incontinence and asymmetry. In Study 3, 19/50 women reported moderate to severe incontinence. Asymmetry and symptom severity were significantly correlated (P < 0.001). Patients with incontinence had a significantly higher asymmetry score than their continent counterparts. CONCLUSION: Functional asymmetry of anal sphincter innervation is significantly associated with incontinence symptoms, but only after childbirth-related sphincter injuries and therefore, should be regarded as an additional risk factor.

Adult↗

PubMed2006

Electromyography of pelvic floor muscles.

Pelvic floor muscles (PFM) are intimately involved in function of lower urinary tract, the anorectum and sexual functions, therefore their neural control transcends the primarily important somatic innervation of striated muscle, as they are directly involved in "visceral activity". Neural control of pelvic organs is affected by a unique co-ordination of somatic and autonomic motor nervous systems. Visceral and somatic sensory fibres supply sensory information from pelvic organs; their input influences through central integrative mechanisms also pelvic floor muscle activity. Anatomically, somatic afferent and efferent nerves of the sacral cord segments, reflexly integrated at the spinal cord and brainstem level, conduct neural control of PFM. The inputs from several higher centres influence the complex reflex control and are decisive for voluntary control, and for socially adapted behaviour related to excretory functions.

Autonomic Nervous System↗

PubMed2006

Pavlovian conditioning of nausea and vomiting.

Cancer patients undergoing cytotoxic drug treatment often experience side-effects, the most distressing being nausea and vomiting. Despite antiemetic drugs, 25-30% of the chemotherapy patients report these side-effects when being re-exposed to the stimuli that usually signal the chemotherapy session and its drug infusion. These symptoms are called anticipatory nausea and anticipatory vomiting. The present paper summarizes the evidence that anticipatory vomiting is acquired by Pavlovian conditioning, and, consequently, may be alleviated by conditioning techniques. To explore the mechanisms that induce and alleviate conditioned nausea and vomiting further, a conditioned nausea model was established in healthy humans using body rotation as the nausea-inducing treatment. The validity of this motion sickness model to examine conditioning mechanisms in the acquisition and alleviation of conditioned nausea was demonstrated. Cortisol and tumor-necrosis factor-alpha were elevated as endocrine and immunological correlates of nausea. Data in the rotation-induced motion sickness model indicated that gender is an important moderator variable to be considered in further studies. The paper concludes with a review of applications of the demonstrated conditioning principles as interventions to ameliorate distressing anticipatory nausea or anticipatory vomiting in cancer patients undergoing chemotherapy.

Animals↗

PubMed2006

Functional cortical imaging of nausea and vomiting: a possible approach.

From a naive point of view, a study on functional cortical imaging of nausea and vomiting should deliver insight into the basic cortical mechanisms, connections, and time courses, of nausea and vomiting as perceived and processed in the human brain of affected subjects. Until now the brain's response to nausea and vomiting are only inadequately characterized, because studies have been focused mostly on understanding the different mechanisms leading to nausea rather than to cortical activations during nausea or vomiting, respectively. Consequently, the imaging of the "personal experience" of nausea and vomiting can currently be regarded as terra incognita. Nonetheless, the wide variety of the results published on diverse aspects of the topic can be helpful in providing guidelines for a paradigm to further investigations. This paper presents a brief outline for a study on the functional imaging of nauseated humans by means of functional magnetic resonance imaging (fMRI).

Brain Mapping↗

PubMed2006

Endocrine correlates of acute nausea and vomiting.

This paper gives an overview of studies investigating endocrine changes in acute nausea and vomiting. The aetiology of nausea and vomiting is not fully understood, but it has been shown that different stress hormones are released into circulation during motion sickness. Studies with animals and humans have shown that acute nausea activates the hypothalamo-pituitary-adrenal axis and the neurohypophyseal system. So-called stress hormones, like adrenocorticotropic hormone, cortisol, and antidiuretic hormone, are released concomitant with nausea and vomiting in motion sickness, but do not seem to be involved in the aetiology of motion sickness. Nevertheless, plasma levels of stress hormones more or less correlate to the intensity of nausea related symptoms. Although gastroenteropancreatic hormones are involved in gastrointestinal motility, there are only few data describing their changes in response to acute nausea or vomiting.

Animals↗

PubMed2006

Segregation of visceral and somatosensory afferents: an fMRI and cytoarchitectonic mapping study.

Ano-rectal stimulation provides an important model for the processing of somatosensory and visceral sensations in the human nervous system. In spite of their anatomical proximity, the anal canal is innervated by somatosensory afferents whereas the rectum is innervated by the visceral nervous system. In a functional magnetic resonance (fMRI) experiment, we examined the cerebral responses to pneumatic balloon distension of these two structures to test whether somatosensory and visceral stimulation elicited distinct brain activations in spite of their spinal convergence. The specificity of the identified activations was analyzed by Bayesian mixed effects modeling. Activations in the parietal operculum were also compared to the location of cytoarchitectonically defined areas OP 1-4, which are part of the secondary somatosensory cortex (SII), to analyze whether the SII region was activated by anal and/or rectal stimulation. The lowest segregation between visceral and somatosensory stimuli was in the insular cortex, which supports the interpretation of the insula as an integrative region, receiving input from different sensory modalities. The most distinct segregation was found in the fronto-parietal operculum. Here the activations following anal and rectal stimulation were not only functionally but also anatomically distinct. Anal sensations were processed similar to other somatosensory stimuli in the SII cortex (area OP 4). Rectal afferents on the other hand were not processed in SII. Rather, they evoked activation at a more anterior location on the precentral operculum. These results demonstrate a functionally and anatomically distinct processing of somatosensory and visceral afferents in the human cerebral cortex.

Adult↗

PubMed2006

Psychobiology of the placebo response.

The nature and determinants of the placebo response are widely unknown and are discussed controversially. This review presents a unifying concept for the understanding of the placebo response in clinical trials and practice based on three components: "Regression to the mean", "Pavlovian conditioning", and "Signal detection theory", and discusses the respective literature in light of experimental and clinical findings from psychology, psychiatry, neurology, and gastroenterology, with specific emphasis on "brain imaging" of the placebo response.

Animals↗

PubMed2006

Upper and lower gastrointestinal motor and sensory dysfunction after human spinal cord injury.

This chapter describes the results of investigations of the upper and lower gastrointestinal tract in subjects with complete and incomplete spinal cord injury. In one study, gastric emptying was investigated and found delayed. The delay was tentatively attributed to a colo-gastric inhibitory reflex triggered by inappropriate colonic emptying. In another study, anorectal motor and sensory functions were measured. Decreased tone of the internal anal sphincter, exaggerated recto-anal reflexes following rectal distension and spontaneous high-amplitude rectal contractions at low distension volumes were among the findings of the study. Some of the subjects, classified as having a complete injury according to usual clinical criteria (American Spinal Injury Association, ASIA), reported sensation of distension of the rectum. This raises the issue of the need for better methods for the clinical assessment of sensory transmission in the spinal cord. Promising results obtained with functional magnetic resonance imaging of the brain during rectal stimulation in a small group of paraplegics, with complete injuries by ASIA criteria, showed evidence of activation of several brain regions.

Animals↗

PubMed2006

Gender and race as determinants of nausea induced by circular vection.

BACKGROUND: Within- and between-subject variability of susceptibility for motion sickness is well established, but which factors determine susceptibility is less well known. OBJECTIVE: We investigated whether and to what degree sex, race, and head movements contribute to the development of nausea and vomiting (N&V) during pseudorotation in a vection drum in healthy participants. METHODS: Male and female, Chinese and white subjects were exposed to 5x1 minute of circular vection in a conventional rotation drum, with half of the participants performing nausea-enforcing head movements. The symptom ratings (SR) at baseline and after stimulation, the time to perception of illusory self-motion (vection), and the total rotation tolerance (RT) were noted and compared between groups using a 2x2x2 analysis of variance. RESULTS: A total of 48 healthy young adults (24 Chinese, 24 white; 12 males, 12 females in each group) screened for susceptibility to develop motion sickness participated in this study. SR at baseline and after rotation were significantly lower in Chinese compared with white subjects (for baseline SR: F=20.04, P<0.001; for maximal SR: F=7.09, P=0.011). Vection was equal between both groups, with no effects of gender or head movements. Rotation tolerance was significantly shortened for Chinese compared with white participants (mean [SEM], 216.5 [15.4] sec vs 262.6 [11.3] sec, respectively; F=7.21, P=0.011), with independent influence of head movements (F=8.84, P=0.005) but not of gender. CONCLUSIONS: In this study, the strongest intrinsic factor that contributed to N&V during circular vection was racial origin, whereas sex played a minor role in the degree of N&V under the conditions studied. Head movement-induced vestibular stimulation was a further contributing factor.

Adult↗

PubMed2006

Functional anorectal disorders.

This report defines criteria for diagnosing functional anorectal disorders (ie, fecal incontinence, anorectal pain, and disorders of defecation). Functional fecal incontinence is defined as the uncontrolled passage of fecal material recurring for > or =3 months in an individual with a developmental age of > or =4 years that is associated with: (1) abnormal functioning of normally innervated and structurally intact muscles, and/or (2) no or minor abnormalities of sphincter structure and/or innervation insufficient to explain fecal incontinence, and/or (3) normal or disordered bowel habits (ie, fecal retention or diarrhea), and/or (4) psychological causes. However, conditions wherein structural and/or neurogenic abnormalities explain the symptom, or are part of a generalized process (eg, diabetic neuropathy) are not included within functional fecal incontinence. Functional fecal incontinence is a common, but underrecognized symptom, which is equally prevalent in men and women, and can often cause considerable distress. The clinical features are useful for guiding diagnostic testing and therapy. Functional anorectal pain syndromes include proctalgia fugax (fleeting pain) and chronic proctalgia; chronic proctalgia may be subdivided into levator ani syndrome and unspecified anorectal pain, which are defined by arbitrary clinical criteria. Functional defecation disorders are characterized by 2 or more symptoms of constipation, with > or =2 of the following features during defecation: impaired evacuation, inappropriate contraction of the pelvic floor muscles, and inadequate propulsive forces. Functional disorders of defecation may be amenable to pelvic floor retraining by biofeedback therapy (such as dyssynergic defecation).

Anus Diseases↗

PubMed2006

Internet-based assessment of bowel symptoms and quality of life.

OBJECTIVES: We wished to determine the value of an open-access internet questionnaire for assessment of upper and lower gastrointestinal symptoms and health-related quality of life. METHODS: Between January 2002 and June 2005, a symptom scale for upper gastrointestinal and lower gastrointestinal symptoms was placed on a genuine website (www.gesundheits-umfrage.de) and linked to the website of the German irritable bowel syndrome patient group (www.Reizdarmselbsthilfe.de). Patients were asked to report gastrointestinal symptoms that had occurred during the last month. Patients who finished this symptoms questionnaire and acknowledged more than two of a total of eight upper gastrointestinal symptoms and/or more than two of 16 lower gastrointestinal symptoms were immediately offered the assessment of their health-related quality of life by a validated general quality of life scale--the patient general well-being inventory--a 22-item scale with six subscales (anxiety, depression, general well-being, self-control, health, and vitality) and a global scale. Total patient general well-being inventory scores and subscale values were correlated to upper gastrointestinal and lower gastrointestinal symptom scores including the Rome I definition of the irritable bowel syndrome, and to social variables. RESULTS: Five thousand two hundred and fifty-six individuals completed symptom assessment. Out of these, 4431 had three or more upper gastrointestinal symptoms, the mean number of upper gastrointestinal symptoms reported was 3.2+/-2.0; 4456 had three or more lower gastrointestinal symptoms (mean: 10.3+/-3.3), and 3187 met the Rome I criteria for irritable bowel syndrome. A total of 3316 individuals completed the patient general well-being inventory assessment (1156 men, 2160 women, mean age: 37.7+/-12.3 years). Upper gastrointestinal, lower gastrointestinal, and total symptom score were higher in women than in men (P < 0.001), and significantly correlated to the global quality of life assessment. Family status affected the symptom scores (higher in singles) and quality of life scores (lower in people living in partnership for health, but higher for vitality and depression). Age correlated negatively with upper gastrointestinal, lower gastrointestinal, and with total symptom scores as well as with some patient general well-being inventory scores. CONCLUSION: Symptom and quality of life assessment using an open internet questionnaire is feasible and generates data which are, in large, comparable to those from other sources of assessment, despite the fact that the population addressed is, on average, moderately younger than previously studied cohorts.

Adolescent↗

PubMed2006

mu-Opiate receptor agonists -- a new pharmacological approach to prevent motion sickness?

AIMS: Stress hormones might be involved in motion sickness. The influence of loperamide on kinetosis-induced nausea and stress hormone release was investigated in a placebo-controlled, cross-over study. METHODS: Standardized rotation around the vertical axis combined with head movements was used to induce nausea 3 h after 16 mg loperamide or placebo (n = 8). Plasma antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH) and nausea ratings were investigated. RESULTS: After loperamide nausea was significantly lower (P < 0.02). ACTH (P < 0.05) and ADH levels (P < 0.02) increased significantly in both settings, but were lower after loperamide. CONCLUSIONS: The susceptibility to develop kinetosis-induced nausea and stress hormone release is decreased by loperamide, although the site of action remains speculative.

Adrenocorticotropic Hormone↗

PubMed2006

Gastric emptying effects of dietary fiber during 8 hours at two simulated cabin altitudes.

BACKGROUND: In a questionnaire survey, long-distance flying staff of a charter airline reported significantly more dyspeptic symptoms than did short-haul crewmember and ground personnel (belching: 57% vs. 37%, bloating: 51% vs. 36%). To elucidate the reason for increased frequency of gastrointestinal symptoms during long-distance flights, we investigated the effects of altitude and diet on gastric emptying, cardiovascular function, and bodily complaints. METHODS: In a 2 x 2 repeated measurement design we simulated an 8-h flight in a hypobaric chamber in 16 healthy men subjected to 2 meal conditions (high fiber vs. low fiber) on separate days, and assigned to either a flight altitude of 2500 m (8200 ft) or 1000 m (3280 ft). The subjects were blinded toward altitude. Heart rate and gastrointestinal symptoms were taken every hour, and gastric emptying was assessed by 13C-octanoic acid breath-test. In a separate experiment, we examined the effect of the two test meals (2 g vs. 20 g of fiber) in 30 healthy men under conventional laboratory conditions and found no significant differences. RESULTS: At an altitude of 2500 m, heart rate was significantly increased independent of the dietary condition. Gastric emptying (T1/2) was significantly delayed at 2500 m (8200 ft) when a high-fiber meal was given (146.3 +/- 58.4 min low fiber vs. 193.9 +/- 54.3 min high fiber). The symptom score for gastric distension (mean: 1.33 +/- 0.3 vs. mean: 1.07 +/- 0.15) and bloating (mean: 1.82 +/- 0.47 vs. mean: 1.34 +/- 0.35) were also significantly increased at 2500 m for the high-fiber meal compared with the low-fiber meal. CONCLUSIONS: Flight altitude is a physiological load. In combination with a high-fiber diet, this induces significant delays in gastric emptying that may explain symptoms of cabin and cockpit crew and passengers on long-distance flights.

Adult↗

PubMed2005

Temporal characteristics of feeding behavior in the Munich miniature pig.

UNLABELLED: Correlations between meal size and inter-meal intervals as a characteristic of ingestive behavior are generally calculated utilizing Pearson's correlation coefficient. However, this commonly used method may exhibit disadvantages and methodological problems when dealing with dependent time series. Alternatively, a modified version of Pearson's r (r(diff)) or a nonparametric procedure, Pfanzagl's T combined with an expanded sampling theorem offer a statistical alternative for correlational analysis, robust to stochastic interdependencies between time series. In two studies, porcine self-initiated feeding behavior was observed in a closed economy setup, and a comparison of all three correlation coefficients was performed. STUDY 1: Twelve Munich mini-pigs were observed for 2 weeks. The rate of food ingestion was a stable characteristic of each individual pig, feeding and defecation behavior were temporally associated and light/dark cycle differences were seen for feeding. STUDY 2: Eight Munich mini-pigs were studied for 4 weeks. Kendall's Tau was utilized to test the stability of feeding behavior across weeks. Stability increased over time and feeding was more stable during the light period. Both correlation measures revealed a strong association between meal size and inter-meal intervals. CONCLUSION: Munich-miniature pigs exhibited a stable pattern of self-initiated ingestive and excretory behaviors. In both studies, Pfanzagl's T-values as well as r(diff)-values revealed a corresponding and consistent association between meal size and inter-meal intervals. In combination with the conventional Pearson's r, all three coefficients characterize different aspects of feeding behavior.

Animals↗

PubMed2005

Sex-specific adaptation of endocrine and inflammatory responses to repeated nauseogenic body rotation.

It has been shown that stress changes stimulated pro-inflammatory cytokine production and the sensitivity of stimulated cytokine production to glucocorticoid suppression. While glucocorticoid secretion habituates in response repeated stimulation, it is not known whether stimulation and suppression of cytokine production are also subject to adaptation. Eight healthy young subjects were exposed to repeated nauseogenic body rotation on four consecutive days. On each day subjects were rotated around the vertical axis up to five times for a period of 1 min or until subjects chose to stop due to nausea. Blood and saliva samples were obtained before and after rotation for assessment of cortisol, ACTH, plasma vasopressin (ADH), in vitro TNF-alpha and IL-6 production and glucocorticoid sensitivity of TNF-alpha and IL-6 production. Rotation induced increases of ACTH, cortisol, and ADH in the first session. All endocrine responses habituated over time, except for the free cortisol response in men. Pro-inflammatory cytokine production showed a sex-specific response pattern with increases in men and decreases in women in the first session vs. increases in men and women in the last session. Response patterns of GC sensitivity also changed over time: in the first session, sensitivity increased only in men, but in the last session, GC sensitivity decreased in all subjects. In conclusion, in response to repeated nausea induction, habituation occurs only in the endocrine system and predominantly in women. In the immune system, response patterns change in the favor of inflammatory conditions, with increases in stimulated IL-6 and TNF-alpha and decreases in the effectiveness of glucocorticoid suppression of these cytokines. These presumably unfavorable changes in the inflammatory system are more pronounced men.

Adaptation, Physiological↗

PubMed2005

Effects of ethnicity and gender on motion sickness susceptibility.

INTRODUCTION: Susceptibility to motion sickness (MS) is known to be affected by gender and ethnic origin, but whether gender and ethnicity are interacting is unknown. METHODS: We investigated MS development in healthy Caucasian subjects (n = 227), and in subjects of Chinese origin (n = 82). All subjects were exposed to nausea-inducing body rotations in a rotation chair, and rotated around the yaw axis for 5 x 1 min, while they were instructed to move their heads. Prior to rotation, subjects had to fill out a motion-sickness susceptibility questionnaire (MSSQ). Total rotation tolerance time (RT) was noted. Symptom ratings (SR) were performed at the beginning, and immediately after the end of each rotation, and 15 and 30 min later. RESULTS: The average RT was significantly higher in Caucasian (163 +/- 6 s) than in Chinese subjects (111 +/- 7 s) (F = 24.84, p < 0.0001). The adult MSSQ score was significantly lower in Caucasians (17.8 +/- 1.1) than in Chinese volunteers (24.2 +/- 2.1) (F = 6.05, p = 0.014). Maximal SR post rotation was similar in Chinese and Caucasian subjects. RT was highly predictable from the MSSQ scores, but separate for both genders. CONCLUSION: Susceptibility to MS is affected by both ethnic origin and by gender in a rather complex fashion. The most reliable prediction of RT can be based on the individual's history as assessed by the MSSQ.

Adult↗

PubMed2004

Functional asymmetry of pelvic floor innervation and its role in the pathogenesis of fecal incontinence.

UNLABELLED: While the regular and symmetric innervation of the pelvic floor has been regarded as "established" for many years, recent data indicate that asymmetry of innervation of the sphincters may exists and may contribute to the occurrence and severity of incontinence symptoms in case of pelvic floor trauma. METHODS: A systematic review of published papers on asymmetry of sphincter innervation was performed including studies in healthy volunteers and patients with incontinence. 234 consecutive patients with fecal incontinence were investigated by means of side-separated mass surface EMG from the left and right side anal canal, these data were correlated to clinical and anamnestic findings. RESULTS: The literature survey indicates that asymmetry of sphincter innervation exists in a subgroup of healthy male and female volunteers, and may be a risk factor to become incontinent in case of trauma. Patients with incontinence in whom asymmetry of sphincter innervation could be shown more frequently reported a history of pelvic floor trauma during childbirth. Childbirth per se but not the number of deliveries predicted sphincter asymmetry. Asymmetrically innervated sphincters show a compromised sphincter function in routine anorectal manometry. CONCLUSION: Assessment of sphincter innervation asymmetry may be of value in clinical routine testing of patients with incontinence. However, a new technology is needed to replace mass surface EMG by multi-electrode arrays on a sphincter probe. This is one of the goals of the EU-sponsored research project OASIS.

Electric Stimulation↗

PubMed2004

Postoperative colonic motility increases after early food intake in patients undergoing colorectal surgery.

BACKGROUND: Stimulation of colonic motility by the gastrocolonic response may help to reduce inhibition of gastrointestinal motility after colorectal surgery. We aimed to investigate whether postoperative colonic motility is increased after early food intake. METHODS: Nineteen patients undergoing colorectal surgery and 7 healthy volunteers were investigated. Colonic motility was recorded with a combined manometry/barostat system, and the effect of a standard 500-kcal meal was evaluated once in healthy volunteers and in 15 patients on the first and second postoperative day. Four patients remained unfed, serving as controls. RESULTS: In patients, the colonic motility index increased from 12 +/- 5 at baseline to 65 +/- 24 mm Hg after the meal on postoperative day 1 (mean +/- SEM; P < .01), while barostat bag volumes decreased, indicating a rise in colonic tone. On day 2, the motility index was 62 +/- 17 mm Hg at baseline and did not change after the meal. In unfed controls, no change was observed during colonic motility recordings on both postoperative days. In healthy volunteers, the colonic motility index increased from 98 +/- 52 at baseline to 151 +/- 58 mm Hg postprandially (P < .05). CONCLUSIONS: As in healthy volunteers, there is a potential to stimulate colonic motility by early food intake in postoperative patients. This may help to improve prolonged colonic motility disorders after colorectal surgery.

Adult↗