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Biomedical subjects

T Frieling

Publications and source records attributed to T Frieling.

At least 55 records · Page 3Linked to original sources
PubMed1997

Anal endosonography and manometry: comparison in patients with defecation problems.

PURPOSE: Correlations between anal sphincter function as assessed by anorectal manometry and anal sphincter anatomy measured by endoluminal ultrasound have been reported in the literature both for patients and for healthy individuals but have not been confirmed by other authors. METHODS: For a larger series of patients (152 consecutive patients, mean age 54.1 +/- 15.5 years; female:male ratio, 111:41) with anorectal dysfunctions such as incontinence (n = 92), constipation (n = 37), and other symptoms (n = 23), diagnostic work-up included conventional multilumen anorectal manometry to evaluate internal sphincter pressure at rest, maximum external sphincter squeeze pressure during contraction, and endoanal sonography to determine anal sphincter integrity and to measure dorsal, left lateral, and right lateral diameter of the internal anal sphincter (IAS) and external anal sphincter (EAS) muscles. RESULTS: Maximum squeeze pressure was significantly correlated to muscle thickness of the EAS (P = 0.001). No association was found between resting pressure and IAS diameter. Women had significantly lower resting and squeeze pressures than men (P = 0.008 and P = 0.003, respectively), but age-related changes of function were only found for resting pressure. Endosonographic values of IAS and EAS did not differ between genders but were significantly correlated with age (P = 0.008 and P = 0.02, respectively). Because all correlations were rather weak, they only can explain a small portion of data variance. CONCLUSION: Anal manometry and anal ultrasound, therefore, are of complementary value and are both indicated in adequate clinical problems.

Adult↗
PubMed1997

Leukotriene-evoked cyclic chloride secretion is mediated by enteric neuronal modulation in guinea-pig colon.

Short term exposure to leukotrienes evoked a well known nerve mediated increase in short circuit current. It is unknown whether leukotrienes evoke in addition oscillations in chloride secretion, as has been reported for some of the other mediators released during inflammation. Therefore, the aim of this study was to characterize the effects of a long time exposure of leukotrienes on mucosal functions. Conventional Ussing chamber, and intracellular recording techniques were used to investigate the actions of leukotriene D4 and C4 on short-circuit current and excitability of submucosal neurons in guinea-pig distal colon. In Ussing chambers, long term exposure to leukotriene D4 or C4 evoked rhythmic oscillations in short-circuit current in 35% and 50% of tissues, respectively. These current bursts were blocked by tetrodotoxin, atropine, hexamethonium and piroxicam. Secretory response to short term exposure of leukotrienes was significantly higher in tissues exhibiting current bursts. Likewise, the potentiating effects of leukotrienes on the response to field stimulation was only observed in tissues exhibiting current bursts. In intracellular recording experiments, leukotriene C4 evoked activation of submucosal neurons that was partly sensitive to indomethacin; no oscillations in neuronal excitability could be demonstrated. Results suggested that long term exposure to leukotrienes evoked current bursts that were mediated by neural, cholinergic mechanisms as well as endogeneous prostaglandins.

Animals↗
PubMed1997

Resolution of hydatid liver cyst by spontaneous rupture into the biliary tract.

Among the complications of hydatid liver disease, spontaneous cyst rupture into the biliary tract is unusual, occurring in 3.2-17% of cases. Its endoscopic management has been reported rarely, and corresponding complete photodocumentation is unique. Such a case is described and comprehensively illustrated in a 48-year-old immunocompromised man, presenting with upper abdominal pain, obstructive jaundice, and fever. Impaction of hydatid material into the common bile duct and the papilla of Vater was relieved endoscopically, and the patient was consecutively treated with two courses of mebendazole. This management resulted in complete clinical resolution of hepatic hydatosis after 8 months of follow-up. Complications of overt cyst perforation may be allergic, obstructive, secondary infectious, or metastatic. Ultrasound and computed tomography are complementary tools for diagnosis of hepatic echinococcosis, with endoscopic retrograde cholangiography being the "gold standard" in confirming rupture into the biliary system. Laboratory results are usually non-specific. While surgical excision is the treatment of choice, selected patients may primarily be managed endoscopically, followed by anthelminthic therapy.

Cholangiography↗
PubMed1997

Differential effects of inflammatory mediators on ion secretion in the guinea-pig colon.

Bi-directional interactions between the enteric nervous system and the immune system play an important role in gut inflammation. We therefore investigated the effects of the inflammatory mediators, prostaglandin (PGD2, PGE2, PGI2, and PGF2 alpha) and leukotriene (LTC4), on guinea-pig colonic secretion and on electrophysiological behaviour of submucosal neurones. In Ussing chambers, all inflammatory mediators evoked a dose-dependent increase in short circuit current (Isc) that represented electrogenic chloride secretion. The secretory response was significantly reduced by tetrodotoxin (TTX) and atropine suggesting involvement of cholinergic submucosal neurones. Long-term application of prostaglandins and LTC4 induced TTX- and atropine-sensitive cyclical chloride secretions. Intracellular recordings revealed activation of submucosal neurones by all inflammatory mediators. This activation consisted of depolarisation of the membrane associated with increased spike discharge. Frequently, prostaglandins and LTC4 induced spontaneous occurrence of cholinergic fast excitatory postsynaptic potentials. Results suggest that the role of the enteric nervous system in neuroimmune interactions consists of a potentiation of the direct epithelial effect of inflammatory mediators by the activation of submucosal neurones. Ongoing nerve-mediated cyclical changes in chloride secretion may be interpreted as the induction of intrinsic alarm programs. The effects of inflammatory mediators may serve as a defense mechanism to dilute noxious substances in the lumen.

Animals↗
PubMed1997

Topical benzocaine anaesthesia lacks analgesic effects in painful non-acid oesophagitis.

BACKGROUND: No established treatment exists for pain relief in symptomatic non-acid oesophagitis. One of the most common topical anaesthetics is benzocaine which has been demonstrated to produce excellent analgesia on oral mucous membranes. METHODS: In a prospective, placebo-controlled, balanced, single-blinded study, 26 patients with retrosternal discomfort or odynophagia due to painful non-acid oesophagitis were treated either with oral benzocaine 0.75% solution (n = 14) or with benzocaine-free solvent (placebo, n = 12) at a daily dose of 20-40 mL, for up to 6 consecutive days (median 5.5 days). During the study period patients recorded subjective pain scores for both complaints on visual analogue scales. RESULTS: Benzocaine did not affect pain scores for any of the two symptoms, nor did it alter global subjective or objective assessment of therapy outcome in treated compared to untreated subjects (P > 0.05). There was a non-significant tendency for placebo patients to stop prematurely their study medication more often, because of lack of analgesic efficacy (P = 0.098). CONCLUSIONS: Topical benzocaine cannot be recommended for routine symptomatic pain relief in non-acid oesophagitis. By indirect evidence, it is assumed that pain perception of non-acid oesophagitis is not preferentially mediated by superficially located mucosal nociceptors.

Administration, Topical↗
PubMed1997

Characterization and natural course of cardiac autonomic nervous dysfunction in HIV-infected patients.

OBJECTIVE: To examine the degree, pattern, and natural history of cardiac autonomic nervous dysfunction in patients infected with HIV. DESIGN: Cross-sectional and prospective longitudinal cohort study. SETTING: Primary care and tertiary referral university centre. PARTICIPANTS: Thirty-five consecutive HIV-infected patients who had either not yet developed AIDS (15 pre-AIDS patients) or who were at the Centers for Disease Control and Prevention (CDC) AIDS stage (n = 20), and 29 healthy age- and sex-matched HIV-negative controls. METHODS: Computer-aided power spectral analysis of 15 standardized parameters of heart-rate variability (HRV). RESULTS: Pre-AIDS patients as a group did not exhibit any HRV parameters to be significantly different from healthy controls (P > 0.017), whereas AIDS patients demonstrated reduced HRV in 14 parameters (93.3%) compared with healthy subjects (p > 0.017). Median proportion of abnormal HRV parameters (< 10th percentile of controls) per individual was 9.1% in pre-AIDS patients and 61.3% in AIDS patients (P = 0.0347). Progressive CDC stages inversely correlated to 10 HRV parameters (66.7%; -0.50 < or = r < or = -0.36; P < 0.05). Follow-up testing in 10 pre-AIDS and six AIDS patients after 6-16 months (median, 12.5 months) did not reveal deterioration of HRV (P < 0.05). A dysautonomia symptom score correlated to 10 HRV parameters (66.7%; -0.14 < r < -0.55; P < 0.05). CONCLUSIONS: Cardiac autonomic nervous dysfunction is severe in AIDS patients, although not significant in pre-AIDS patients. Cardiac autonomic nervous dysfunction proceeds with HIV disease progression, although its individual course is slow.

Adolescent↗
PubMed1997

Intestinal protein leakage in the acquired immunodeficiency syndrome.

Body wasting, protein catabolism, and hypoalbuminemia are complicating features of the acquired immunodeficiency syndrome (AIDS). Given their multifactorial causes, the contributing role of intestinal protein loss has not yet been fully elucidated. To quantify enteric protein leakage, determination of fecal alpha 1-antitrypsin (AAT) excretion has been established as an accurate and reliable endogenous marker. We estimated AAT concentration by standard immune nephelometry in duplicate random stool samples of 49 patients with AIDS, and we compared it to that of 43 patients with chronic inflammatory bowel disease and to 34 healthy controls. When compared with healthy persons, patients with AIDS had increased fecal AAT excretion regardless of current opportunistic intestinal infections and fecal AAT excretion similar to that of patients with quiescent chronic inflammatory bowel disease. The ratio of fecal and serum AAT concentration was not different between AIDS patients and healthy controls, although it was consistently increased in those with chronic inflammatory bowel disease. Significant intestinal protein leakage occurs in patients with AIDS, probably due to primary impairment of gut permeability. Enteric protein loss may be an important feature of human immunodeficiency virus-associated enteropathy with altered mucosal barrier function.

AIDS-Related Opportunistic Infections↗
PubMed1997

Solitary hepatic lesions with a hypoechoic rim: value of color Doppler sonography.

OBJECTIVE: A hypoechoic rim around a focal liver lesion as revealed by conventional sonography may be present in malignant liver lesions as well as in benign liver lesions. This study evaluated the potential of color Doppler sonography in differentiating various focal liver lesions with a hypoechoic rim. CONCLUSION: Color Doppler sonography may be helpful in distinguishing focal nodular hyperplasia (FNH) from other focal liver lesions. The characteristic finding of blood flow within the hypoechoic rim of FNH is most likely caused by small vessel abnormalities that have previously been described for FNH.

Case-Control Studies↗
PubMed1997

Pathophysiology of diabetic gastroparesis.

Our understanding of the nature of diabetic gastroparesis has advanced in the last decade due to new investigational procedures (electrogastrography, visceral evoked potential recording), and transferring these insights into clinical routine will be our task in the future. Meanwhile, the clinical relevance of gastroparesis--whether overt or silent--remains unquestioned: proper gastric emptying is a prerequisite for adequate metabolic control, and its disturbance may result not only in further progression of the chronic complications of the disease, but also in the false assumption that these patients are not compliant with their doctor's management--the patients just may have delayed emptying of their stomach without noticing it.

Age Factors↗
PubMed1997

How reproducible are measures of the anal sphincter muscle diameter by endoanal ultrasound?

UNLABELLED: Anal endosonography is an imaging technique for the anal sphincter system and offers analysis of its muscular integrity. It is generally assumed that measurement of the thickness of muscle layers is provided by sonography; however, reproducibility of such measurements have not yet been investigated. METHODS: Study 1: In 10 healthy volunteers, endoanal ultrasound was performed independently by two experienced investigators with two different ultrasound machines, and thickness of the muscle layers of the internal and external anal sphincter was assessed in the position of the intermediate dorsal anal canal in a randomized cross-over fashion. Study 2: In a study of similar design, sonography was performed in nine healthy volunteers by two investigators independently using a single ultrasound machine in three standardized positions (proximal/intermediate/distal anal canal) and the sphincter layers assessed in the left, right, and dorsal segment. RESULTS: Study 1: Both the same investigator with different ultrasound scanners and different investigators with the same machine failed to obtain reproducible results with respect to internal and external anal sphincter muscle layer diameter (four bivariate correlations, all with p > 0.05). Study 2: Standardization of the probe position did not improve the agreement (2 x 9 bivariate correlations, all but two p > 0.05). CONCLUSION: At present, therefore, endoanal ultrasound does not provide reliable morphometric data on anal sphincter muscle diameter. This could explain previously conflicting observations of associations between anal sphincter morphometry and function.

Anal Canal↗
PubMed1997

Cerebral evoked responses to gastrointestinal stimulation in humans.

Recent advances have permitted recording of evoked potentials (EPs) in response to electrical and mechanical stimulation of the gastrointestinal (GI) organs via methods used primarily in clinical neurophysiology. Current research involving stimulation of the esophagus, rectum, and colon, and recording the corresponding responses on the scalp, is being practiced in only a few laboratories. This review examines the engineering aspects of recording EPs, such as characteristics of the stimuli, placement of stimulus electrodes in the GI tract, and enhancement of evoked potential signals. We also discuss the physiological concepts involved in the generation of EPs, and how these compare with somatosensory evoked responses. Current experimental techniques employed by various investigators and results reported from their laboratories are compared. We believe that cerebral EPs to GI stimulation could be useful in studying a number of pathophysiological conditions such as gastroesophageal reflux disease, diffuse esophageal spasm, chronic inflammatory bowel disorders, chronic abdominal pain, and irritable bowel syndrome, among others. We hope that the present review will generate interest in the use of EPs arising out of GI stimulation, aiding in understanding their physiological implications in healthy subjects and in GI disorders.

Cerebral Cortex↗
PubMed1997

[Ulcer hemorrhage: is aggressive surgical therapy still defensible?].

A total of 155 patients admitted with Forrest 1a/2a peptic ulcer bleeding were prospectively recorded. Primarily conservatively treated patients developed recurrent bleeding in 27.4% of cases, with a mortality of 10.5% compared to 8.7% mortality after early elective surgery. In our opinion, the indication for surgery has to be reassessed in patients with Forrest 2a peptic ulcer bleeding.

Follow-Up Studies↗
PubMed1996

Prospective study on the detection of insulinomas by endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: The correct localization of insulinomas using endoscopic ultrasonography (EUS) has been reported to be as high as 80% in multicenter patient cohorts. PATIENTS AND METHODS: Over 24 months, we prospectively investigated 14 patients (11 women, three men) with a definite biochemical diagnosis of endogenous hyperinsulinism prior to surgical exploration and removal of an insulinoma. The endoscopic investigator was not aware of any other imaging results if they had been performed in referring hospitals. RESULTS: The overall sensitivity of EUS in the detection of pancreatic insulinomas was 57% (eight of 14 tumors); the sensitivity for insulinomas in the head of the pancreas was 83% (five of six); and 37% (three of eight) for tumors in the tail of the pancreas. The actual median diameter of undetected tumors was 11 x 9.5 mm, the median volume 0.66 ml (range 0.13 - 2.6 ml). The median diameter of correctly detected tumors was 16 x 11 mm, the median volume 1.37 ml (range 0.7 - 6.3 ml), the differences not being significantly different. In two patients, false-positive results were caused by peripancreatic lymph nodes. CONCLUSIONS: The sensitivity of EUS in the detection of pancreatic insulinomas depends on the location of the tumor, and possibly on the size of the tumors. Tumors not detected by EUS were likely to be smaller than detected tumors, and were likely to be located in the tail of the pancreas.

Adult↗
PubMed1996

Comparison between intraluminal multiple electric impedance measurement and manometry in the human oesophagus.

Conventional oesophageal manometry and intraluminal electrical impedance measurement were simultaneously applied in eight healthy volunteers to study the effect of wet and semisolid bolus viscosities on oesophageal motility and bolus transit. Contraction front velocity measured by electrical impedance and manometry were identical for wet and semisolid swallows and highly associated. Bolus front velocity as measured by electrical impedance was significantly faster than contraction front velocity in both wet and semisolid swallows. Bolus front velocity during semisolid swallows was significantly slower compared to wet swallows. It is concluded that intraluminal electrical impedance measurement is a reliable technique to detect oesophageal motility as well as to differentiate between transit of wet and semisolid bolus consistencies.

Adult↗
PubMed1996

Electrically evoked cerebral potentials during esophageal distension at perception and pain threshold.

OBJECTIVE: To investigate esophageal sensory function in normal volunteers. METHODS: The method of evoking cerebral potentials (EPs) after electrical stimulation of the esophagus was applied in eight healthy male volunteers, 20-40 yr old. Electrical stimulation was obtained via bipolar Ag/AgCl electrodes attached to a latex balloon mounted on a catheter. The balloon was inflated stepwise to perception and pain thresholds. At the perception threshold for balloon distension, the intensity of electrical stimulation was increased stepwise to perception threshold for electrical stimulation, and subsequently to 2-fold, 4-fold, and 8-fold perception threshold. EPs were recorded from the vertex (Cz) and forehead (Fz, reference) and compared between the increasing electrical stimulation intensities and between perception and pain thresholds for mechanical stimulation. RESULTS: The results show that amplitudes of EPs significantly increased with increasing electrical stimulation intensities, whereas latencies of EPs were not affected. Latencies and amplitudes of EPs were comparable at perception and pain thresholds for esophageal distension. CONCLUSIONS: The study suggests that repetitive electrical stimulation of the human esophagus is predominantly mediated via vagal A-delta fibers. The unaltered EPs at the perception and pain thresholds suggest that vagal A-delta fibers are not involved in mediation of pain. The findings support the view that painful and nonpainful stimuli are mediated via different visceral afferents between the esophagus and brain in humans.

Adult↗
PubMed1996

Comparison of anal sonography with conventional needle electromyography in the evaluation of anal sphincter defects.

OBJECTIVE: A comparison of anal sonography with conventional electromyographic mapping in the evaluation of anal sphincter defects was the aim of this study. METHODS: In 23 patients with defecatory problems referred for conventional needle electromyography (EMG), anal endosonography, with a 7.5-MHz, 355 degrees scanner, was performed before EMG to determine the structural integrity of the external anal sphincter. If lesions were found, they were described in terms of location and extent. Subsequently, concentric needle EMG of the external sphincter was performed circumferentially to locate muscle parts exhibiting normal and diminished or missing muscle activity. Lesions found by EMG were also described like those found by sonography. RESULTS: Of 23 patients, eight exhibited no abnormalities on EMG, and no muscle defects were identified endosonographically in any of these patients. In the remaining 15 patients, EMG showed either an incomplete pattern of interference or a complete absence of voluntary activity; in all of these patients endosonography also identified structural deficit. In 14 of these 15 patients, abnormalities were found at the same location with both endosonography and EMG. In the remaining patient, the two techniques identified structural and functional abnormalities at different locations. CONCLUSION: Although EMG is the gold standard for assessment of the functional relevance of muscle defects, anal endosonography yields a sensitivity and specificity of almost 100%.

Adult↗
PubMed1995

Effects of prostaglandin F2 alpha (PGF2 alpha) and prostaglandin I2 (PGI2) on nerve-mediated secretion in guinea-pig colon.

We have applied conventional flux-chamber and intracellular recording methods to investigate the effects of the prostaglandins PGF2 alpha and PGI2 upon epithelial ion transport and on the electrical behaviour of submucosal neurones in guinea-pig colon. In flux-chamber experiments on segments of colon, both prostaglandins evoked a dose-dependent increase in short-circuit current that was reduced in chloride-depleted Krebs solution and by serosal addition of tetrodotoxin or atropine, but was unaffected by hexamethonium. These results indicate activation of chloride secretion via submucosal neurones. The response to PGF2 alpha was decreased by piroxicam. Application of PGF2 alpha or PGI2 to submucosal neurones evoked depolarization of the membrane potential associated with an enhanced spike discharge. The depolarizing response was tetrodotoxin insensitive, indicating a direct effect of the prostaglandins on the impaled neurones. Membrane depolarization was frequently associated with the occurrence of fast excitatory postsynaptic potentials, suggesting in addition that part of the excitatory effect is mediated by the activation of neural circuits that drive the impaled neurone synaptically. The results of this study indicate that the secretory effects of prostaglandins are mediated in part by submucosal neurones and further suggest that the colonic submucosal plexus may function as an amplifier to enhance the epithelial response to inflammatory mediators.

Animals↗