The rectum, anal sphincter and puborectalis muscle show different contraction wave forms during prolonged measurement with a simulated feces

Contractile patterns in rectum, puborectalis muscle and anal sphincter must be studied to understand defecation. Six subjects had contractile waveforms studied with Fecobionics. Symptom questionnaires, balloon expulsion test and anorectal manometry were done for reference. The Fecobionics bag was filled in rectum to urge-to-defecate volume and measurements were done for 4 h before the subjects attempted to evacuate the device. Pressures and bend angle (BA) variations were analyzed with Fast Fourier Transformation. Four normal subjects exhibited low frequency waves (< 0.06 Hz) for pressures and BA. The waves were uncoordinated between recordings, except for rear and bag pressures. Peak wave amplitudes occurred at 0.02-0.04 Hz. Pressures and the BA differed for peak 1 (p < 0.001) and peak 2 amplitudes (p < 0.005). The front pressure amplitude was bigger than the others (rear and BA, p < 0.05; bag, p < 0.005) for peak 1, and bigger than bag pressure (p < 0.005) and BA (p < 0.05) for peak 2. One subject was considered constipated with lower front pressure amplitudes compared to normal subjects and increased amplitudes for other parameters. The sixth subject was hyperreactive and differed from the other subjects. In conclusion, the rectum, anal sphincter and puborectalis muscle showed different contraction waves during prolonged measurements. The data call for larger studies to better understand normal defecation, feces-withholding patterns, and the implications on anorectal disorders.

Optimizing the Utility of Anorectal Manometry for Diagnosis and Therapy: A Roundtable Review and Recommendations

BACKGROUND & AIMS

Anorectal manometry (ARM) is a comprehensive diagnostic tool for evaluating patients with constipation, fecal incontinence, or anorectal pain; however, it is not widely utilized for reasons that remain unclear. The aim of this roundtable discussion was to critically examine the current clinical practices of ARM and biofeedback therapy by physicians and surgeons in both academic and community settings.

METHODS

Leaders in medical and surgical gastroenterology and physical therapy with interest in anorectal disorders were surveyed regarding practice patterns and utilization of these technologies. Subsequently, a roundtable was held to discuss survey results, explore current diagnostic and therapeutic challenges with these technologies, review the literature, and generate consensus-based recommendations.

RESULTS

ARM identifies key pathophysiological abnormalities such as dyssynergic defecation, anal sphincter weakness, or rectal sensory dysfunction, and is a critical component of biofeedback therapy, an evidence-based treatment for patients with dyssynergic defecation and fecal incontinence. Additionally, ARM has the potential to enhance health-related quality of life and reduce healthcare costs. However, it has significant barriers that include a lack of education and training of healthcare providers regarding the utility and availability of ARM and biofeedback procedures, as well as challenges with condition-specific testing protocols and interpretation. Additional barriers include understanding when to perform, where to refer, and how to use these technologies, and confusion over billing practices.

CONCLUSIONS

Overcoming these challenges with appropriate education, training, collaborative research, and evidence-based guidelines for ARM testing and biofeedback therapy could significantly enhance patient care of anorectal disorders.

The PanGut-study: Evoked potentials following rectal balloon distention, a way of evaluating diabetic autonomic neuropathy in the gut?

AIM

There is a lack of methods for investigating the autonomic nerves of the gastrointestinal tract. Our aim was to explore a novel test measuring visceral sensory evoked potentials (EPs) in response to rapid balloon distention in the rectum and compare it to established tests for diabetic neuropathy.

METHOD

Participants with longstanding type 2 diabetes, newly onset, untreated diabetes <1 year, and matched controls, were included. Tests included cardiovascular reflex tests, orthostatic blood pressure, electrical skin conductance assessment, sural nerve testing and monofilament test. The rectal balloon distention pressure at earliest sensation and threshold of unpleasantness were identified and used to elicit mechanical EPs.

RESULTS

The pressure at earliest sensation was higher in people with diabetes, 0.038 (0.012) bar vs. controls 0.030 (0.009) bar, p = 0.002, and in people with signs of peripheral neuropathy, 0.045 (0.014) bar, p < 0.01. Clinical correlations between EP amplitude and latency, and other tests were found.

CONCLUSIONS

Rectal hyposensitivity was associated with both longstanding and early diabetes, indicating enteric sensory dysfunction already in early stages of diabetes. Correlation analyses may indicate that central afferent processing is affected in parallel with peripheral neuronal function.

Recto-anal Pressures in Constipated Men and Women Undergoing High-Resolution Anorectal Manometry

BACKGROUND

In constipated individuals, high-resolution anorectal manometry (HRM) may suggest the presence of a defecatory disorder. Despite known physiological differences between men and women, our understanding of functional anorectal pathophysiology is based upon predominantly female cohorts. Results are generalized to men.

AIMS

To evaluate whether recto-anal pressure patterns in constipated men are similar to those in constipated women.

METHODS

The electronic health records at Mayo Clinic, Rochester were used to identify constipated adult patients, without organic anorectal disease, who had undergone HRM and balloon expulsion testing (BET) in 2018, 2019, and 2020. Comparative analyses were performed.

RESULTS

Among 3,298 constipated adult patients (2,633 women, 665 men), anal and rectal pressures were higher in men. Women more likely to have HRM findings suggestive of a defecatory disorder (39% versus 20%, P < 0.001). Women were more likely to exhibit a type 4 pattern (27% versus 14%, P < 0.001), and less likely to exhibit a type 1 pattern (14% versus 38%, P < 0.001), of dyssynergia. Men were more likely to have an abnormal balloon expulsion test (BET, 34% versus 29%, P = 0.006). Nominal logistic regression demonstrates that male sex, age over 50 years, reduced recto-anal gradient during simulated evacuation, and types 2 and 4 dyssynergia are associated with an abnormal BET.

CONCLUSIONS

In this large retrospective study, constipated men and women exhibited different patterns of dyssynergia both in the presence and absence of an abnormal BET. These findings were independent of sex-specific baseline physiological differences.

Anorectal volume-pressure relations, contraction work, and flow during defecation

Fecobionics is an integrated device that has shown promise for assessment of anorectal function. We used a wireless Fecobionics prototype to visualize defecatory patterns and to compute volume-pressure, contraction work, and flow. Twelve normal subjects were studied. The probe was 10 cm-long and contained pressure sensors and electrodes for impedance planimetry. Pressures, diameters, and volume data during defecation were analyzed. The bag was distended inside rectum to the urge-to-defecate level where after the subjects were asked to evacuate. The contraction work and defecatory flow were computed from the volume changes during expulsion. The minimum anal diameter during the evacuation was 17.6 ± 1.5 mm. The middle diameter recording was 10-20% lower than the front diameter channels and 10-20% bigger than the rear channels. The bag volume at urge correlated with the minimum diameter (r = 0.63). The diameter-pressure and volume-pressure loops were counterclockwise with phases of bag filling, isometric contraction, ejection and anal passage. The defecatory contraction work was 3520 ± 480 mL × cmH2O. The maximum flow during defecation was 302 ± 33 mL/s. The flow was associated with the anal diameter (r = 0.84) but not with the rectoanal pressure gradient (r = 0.14). Volume-pressure loops have a tremendous impact on the understanding of cardiopulmonary pathophysiology. Future studies will shed light on potential clinical impact in defecatory pathophysiology.

Feasibility study of defecation studied with a wireless Fecobionics probe in normal subjects

Several technologies have been developed for assessing anorectal function including the act of defecation. We used a new prototype of the Fecobionics technology, a multi-sensor simulated feces, to visualize defecatory patterns and introduced new metrics for anorectal physiology assessment in normal subjects. Fourteen subjects with normal fecal incontinence and constipation questionnaire scores were studied. The 10-cm-long Fecobionics device provided measurements of axial pressures, orientation, bending, and shape. The Fecobionics bag was distended to the urge-to-defecate level inside rectum where after the subjects were asked to evacuate. Physiological evacuation parameters were assessed. Special attention was paid to the Fecobionics rectoanal pressure gradient (F-RAPG) during evacuation. Anorectal manometry (ARM) and balloon expulsion test (BET) were done as references. The user interface displayed the fine coordination between pressures, orientation, bending angle, and shape. The pressures showed that Fecobionics was expelled in 11.5 s (quartiles 7.5 and 18.8s), which was shorter than the subjectively reported expulsion time of the BET balloon. Six subjects did not expel the BET balloon within 2 min. The F-RAPG was 101 (79-131) cmH₂ O, whereas the ARM-RAPG was -28 (-5 to -47) cmH₂ 0 (p < 0.001). There was no association between the two RAPGs (r²  = 0.19). Fecobionics showed paradoxical contractions in one subject (7%) compared to 12 subjects with ARM (86%). Fecobionics obtained novel physiological data. Defecatory patterns and data are reported and can be used to guide larger-scale studies in normal subjects and patients with defecatory disorders. In accordance with other studies, this Fecobionics study questions the value of the ARM-RAPG.

Rectal Distension Increased the Rectoanal Gradient in Patients with Normal Rectal Sensory Function

BACKGROUND

Frequent observation of abnormal manometric patterns consistent with dyssynergia in healthy volunteers has warranted the need for reassessment of the current methods to enhance the diagnostic value of anorectal manometry in functional defecatory disorders. Whether rectal distention at simulated evacuation will affect anorectal pressure profile and increase rectoanal gradient is not known.

METHODS

One hundred and eight consecutive patients with chronic constipation, 93 females, median age 53 years (interquartile range: 40-65), were studied. Simulated evacuation was performed firstly with empty balloon and subsequently after balloon distention to 50 and 100 ml. Anorectal pressures were compared. We also performed subgroup analysis in relation to outcome of balloon expulsion test (BET). In addition, we studied the effect of rectal distension on the rectoanal pressure gradient with respect to rectal sensory function.

RESULTS

Rectal balloon distension at simulated evacuation improved rectoanal gradient and decreased the rate of dyssynergia during high-resolution anorectal manometry. In subgroup analysis, the increase in rectoanal gradient and correction of dyssynergia with rectal distension was limited to the patients who had normal BET and normal rectal sensory function. Rate of anal relaxation, residual anal pressures, and rectoanal gradient were significantly different between patients with and without normal BET at 50 ml of rectal distension. Rectoanal gradient recorded only after rectal distension, along with BMI and maximum tolerable volumes, could predict BET results independently in patients with chronic constipation.

CONCLUSIONS

Rectal distension during simulated evacuation will affect the anorectal pressure profile. Increase in rectoanal gradient and correction of dyssynergia was only significant in patients with normal rectal sensory function and normal BET.

When gut feelings teach the brain to fear pain: Context-dependent activation of the central fear network in a novel interoceptive conditioning paradigm

The relevance of contextual factors in shaping neural mechanisms underlying visceral pain-related fear learning remains elusive. However, benign interoceptive sensations, which shape patients' clinical reality, may context-dependently become conditioned predictors of impending visceral pain. In a novel context-dependent interoceptive conditioning paradigm, we elucidated the putative role of the central fear network in the acquisition and extinction of pain-related fear induced by interoceptive cues and pain-predictive contexts. In this fMRI study involving rectal distensions as a clinically-relevant model of visceroception, N = 27 healthy men and women underwent differential conditioning. During acquisition training, visceral sensations of low intensity as conditioned stimuli (CS) predicted visceral pain as unconditioned stimulus (US) in one context (Con⁺), or safety from pain in another context (Con^-). During extinction training, interoceptive CS remained unpaired in both contexts, which were operationalized as images of different rooms presented in the MRI scanner. Successful contextual conditioning was supported by increased negative valence of Con⁺ compared to Con^- after acquisition training, which resolved after extinction training. Although interoceptive CS were perceived as comparatively pleasant, they induced significantly greater neural activation of the amygdala, ventromedial PFC, and hippocampus when presented in Con⁺, while contexts alone did not elicit differential responses. During extinction training, a shift from CS to context differentiation was observed, with enhanced responses in the amygdala, ventromedial, and ventrolateral PFC to Con⁺ relative to Con^-, whereas no CS-induced differential activation emerged. Context-dependent interoceptive conditioning can turn benign interoceptive cues into predictors of visceral pain that recruit key regions of the fear network. This first evidence expands knowledge about learning and memory mechanisms underlying interoceptive hypervigilance and maladaptive avoidance behavior, with implications for disorders of the gut-brain axis.

Improving the utility of high-resolution manometry for the diagnosis of defecatory disorders in women with chronic constipation

BACKGROUND

We compared the utility of existing and modified versions of high-resolution manometry for diagnosing defecatory disorders (DD).

METHODS

In 64 healthy and 136 constipated women, we compared left lateral (LL) and seated manometry, and analyzed with existing (ManoView™) and new methods, for discriminating between constipated patients with normal and prolonged rectal balloon expulsion time (BET). In both positions, the rectoanal gradient (RAG) and, for the new analysis, the pressure topography pattern during evacuation were used to discriminate between constipated patients without and with DD.

KEY RESULTS

The BET was prolonged, suggestive of a DD, in 52 patients (38%). During evacuation, rectoanal pressures and the RAG were greater in the seated than the LL position (P≤.001). The new analysis identified 4 rectoanal pressure patterns. In the seated position, the BET was associated with the pattern (P=.0001), being prolonged in, respectively, 45%, 15%, 53%, and 0% of patients with minimal change, anal relaxation, paradoxical contraction, and transmission. Within each pattern, the RAG was greater (ie, less negative, P<.0001) in patients with a normal than a prolonged BET. Compared to the ManoView™ RAG in the LL position, the integrated analysis (ie, pattern and new RAG) in the LL position (P<.01) and the seated ManoView™ gradient (P=.02) were more effective for discriminating between constipated patients without and with DD.

CONCLUSIONS & INFERENCES

Anorectal HRM ideally should be performed in the more physiological seated position and analyzed by a two-tier approach, which incorporates the overall pattern followed by the rectoanal gradient. These findings reinforce the utility of manometry for diagnosing DD.

A Novel High-Density Electromyography Probe for Evaluating Anorectal Neurophysiology: Design, Human Feasibility Study, and Validation with Trans-Sacral Magnetic Stimulation

Fecal incontinence (FI) substantially impairs quality of life and imparts a major socioeconomic burden. Anal sphincter injury and possibly pudendal nerve damage are considered common causes, however, current clinical methods for evaluating their function remain suboptimal. Electromyography (EMG) and pudendal nerve terminal latencies have been applied with some success, but are not considered standard practice due to uncertain accuracy and clinical value. In this study we developed and applied a novel anorectal high-density (HD) EMG probe in humans and pigs to acquire quantitative electrophysiological metrics of the anorectum. In the human trial we assessed somatic pathways and showed that EMG amplitude was greater for tight voluntary squeezes than light voluntary squeezes (0.03 ± 0.02 mV vs. 0.05 ± 0.03 mV). In a porcine model we applied trans-sacral magnetic stimulation to evoke extrinsically activated involuntary pathways and the resulting motor evoked potentials (MEP) were captured using the HD-EMG probe. The mean MEP amplitude at 50% magnetic stimulation intensity output (MSO) was significantly lower that the MEP amplitude at 85, 95 and 100% MSO (1.52 ± 0.50 mV vs. 3.10 ± 0.60 mV). In conclusion, the use of HD-EMG probe in conjunction with trans-sacral magnetic stimulation, for spatiotemporal mapping of anorectal EMG and MEP activity is anticipated to achieve new insights into FI and could offer improved diagnostic and prognostic biomarkers for anorectal dysfunction.

Comparing alternatives to canine rectal thermometry at the axillary, auricular and ocular locations

Body temperature is an important component in the diagnosis and treatment of disease in canines. The rectal temperature remains the standard of obtaining temperature within the clinical setting, but there are many drawbacks with this method, including time, access, animal stress, and safety concerns. Interest in using infrared thermometry in canines to obtain body temperature has grown as animal scientists and veterinarians search for non-invasive and non-contact methods and locations of obtaining canine temperatures. Here, we review evidence on axillary, auricular, and ocular region canine thermometry and the degree to which measurements in these locations are representative of rectal temperature values. Instrumentation refinement and development, as well as morphologic differences, play an important role in the potential correlation between the rectal temperature and these other locations. These caveats have yet to be fully addressed in the literature, limiting the options for those seeking alternatives to rectal thermometry.

Novel Fecobionics Defecatory Function Testing

INTRODUCTION

Defecation is a complex process that can be easily disturbed. Defecatory disorders may be diagnosed using specialized investigation, including anorectal manometry (ARM) and the balloon expulsion test (BET). Recently, we developed a simulated stool named Fecobionics that integrates several tests and assesses pressures, orientation, and bending during evacuation. The aim was to evaluate the feasibility and performance of Fecobionics for assessing defecatory physiology in normal subjects.

METHODS

Physiological expulsion parameters were assessed in an interventional study design. The 10-cm-long Fecobionics probe contained pressure sensors at the front and rear and inside a bag and 2 motion processor units. The bag was distended in the rectum of 20 presumed normal subjects (15 female/5 male) until urge to defecate. ARM-BET was also performed. Three subjects used +2 minutes to evacuate BET, and 1 subject had a high fecal incontinence score. Therefore, the normal group consisted of 16 subjects (13 female/3 male aged 25-78 years).

RESULTS

All subjects reported that Fecobionics evacuation was similar to normal defecation. Fecobionics expulsion pressure signatures demonstrated 5 phases, reflecting rectal pressure, anal relaxation, and anal passage. Preload-afterload loop diagrams demonstrated clockwise contraction cycles. The expulsion duration for BET and Fecobionics was 16 ± 2 and 23 ± 5 seconds (P > 0.2), respectively. The duration of the Fecobionics and BET expulsions was associated (P < 0.001). The change in bending of Fecobionics during defecation was 40 ± 3°.

DISCUSSION

Fecobionics obtained reliable data under physiological conditions. Agreement was found for comparable variables between ARM-BET and Fecobionics but not for other variables. The study suggests that Fecobionics is safe and effective in evaluation of key defecatory parameters.

Effects of abdominal and vaginal hysterectomy on anorectal functions along with quality of life of the patient

Objectives and background

Hysterectomy is the most commonly performed major gynecological operation for both benign and malign gynecologic conditions. After hysterectomy, although some investigators have declared an increased incidence of urinary and anorectal dysfunction, some others could not show any connection.

Methods

The voluntary patients were divided in two groups: abdominal hysterectomy (Group 1) and vaginal hysterectomy (Group 2). Anal manometry and all the other examinations of the patients were performed at the Department of General Surgery Endoscopy Unit of Ankara University, Faculty of Medicine.

Results

When the quality of life of the patients was assessed before the operation and on the 12^th post-operative month via the SF-36 form; it can be seen that body pain parameters of the patients in Group 1 had significantly improved and there is no statistical difference in other parameters. When the effect of hysterectomy on the quality of life of the patients was evaluated by the “Cleveland Clinic Global Quality of Life” form, the statistically significant improvement in the quality of life of the patients in Group 2 was observed.

Conclusion

If the type of operation (vaginal or abdominal) is performed due to benign causes, it does not affect the urinary and anorectal functions of the patients. Depending on the decrease of complaints of the patients, it has a positive effect on the quality of life.

Normal values for assessment of anal sphincter morphology, anorectal motion, and pelvic organ prolapse with MRI in healthy women

BACKGROUND

Endoanal MRI and MR defecography are used to identify anal sphincter injury and disordered defecation. However, few studies have evaluated findings in asymptomatic healthy people. The effects of BMI and parity on rectoanal motion and evacuation are unknown.

METHODS

In 113 asymptomatic females (age 50 ± 17 years, Mean ± SD) without risk factors for anorectal trauma, anal sphincter appearance, anorectal motion, and pelvic organ prolapse were evaluated with MRI. The relationship between age, BMI, and parity and structural findings were evaluated with parametric and non-parametric tests.

RESULTS

The anal sphincters and puborectalis appeared normal in over 90% of women. During dynamic MRI, the anorectal angle was 100 ± 1º (Mean ± SEM) at rest, 70 ± 2° at squeeze, and 120 ± 2° during defecation. The change in anorectal angle during squeeze (r = -.25, P < .005), but not during evacuation (r = .13, P = .25) was associated with age. In the multivariable models, BMI (P < .01) and parity (P < .01) were, respectively, independently associated with the intersubject variation in the anorectal angle at rest and the angle change during squeeze. Ten percent or fewer women had had descent of the bladder base or uterus 4 cm or more below the pubococcygeal line or a rectocele measuring 4 cm or larger. Only 5% had a patulous anal canal.

CONCLUSIONS

In addition to age, BMI and parity also affect anorectal motion in asymptomatic women. These findings provide age-adjusted normal values for rectoanal anatomy and pelvic floor motion.

Human studies of anorectal sensory function

This review addresses three main questions: (1) Why is anorectal sensory function important in humans? (2) What is the evidence for anorectal sensory dysfunction in disease? (3) Can anorectal sensory function be modified for therapeutic benefit?

Local regulatory mechanism to coordinate colorectal motility in rats

The presence of a fecal pellet in the colorectum causes ascending contraction and descending relaxation, propelling the pellet aborally. However, random occurrence of the reflexes at multiple sites would disturb sequential excretion of the pellets, resulting in inefficient defecation. Hence, we postulated that a regulatory mechanism to coordinate peristaltic motility initiated at adjacent portions of the colorectum may exist. Colorectal motility was recorded with balloons located at 2 cm, 5 cm and 7 cm from the anus in vivo in anesthetized rats. The presence of a balloon in the colorectum inhibited motility of the oral side and enhanced motility of the anal side. Both the ascending inhibitory and descending facilitatory actions were unaffected by cutting the pelvic nerves, suggesting little contribution of the lumbosacral defecation center. In contrast, disrupting the continuity of the enteric nervous system abolished the local reflex mechanism. The ascending inhibitory pathway operated in a condition in which facilitatory input from the lumbosacral defecation center was fully activated by intrathecal injection of ghrelin. We also found that functional impairment of the local reflex pathways was evident in rats that recovered from 2,4,6-trinitrobenzensulfonic acid-induced colitis. These results demonstrate that an intrinsic regulatory mechanism to coordinate peristaltic motility initiated at adjacent portions exists in the rat colorectum. The regulation may be beneficial to propel multiple pellets efficiently. In addition, impairment of the local regulatory mechanism might be involved in postinflammatory dysmotility in the colorectum.

Combined effects of retinol, ascorbic acid and α-tocopherol on diurnal variations in rectal temperature of Black Harco pullets subjected to heat stress

The experiment was performed with the aim of determining the effect of co-administration of antioxidant vitamins, retinol, ascorbic acid and α-tocopherol on rectal temperature (RT) fluctuations in pullets during the hot-dry season in Nigeria. Forty-eight Black Harco pullets, aged 16 weeks and weighing 1.5 ± 0.03 kg were divided by simple random sampling into two groups, consisting of 28 treated and 20 control Black Harco pullets. The RTs of 28 treated and 20 control Black Harco pullets were measured hourly for 3 days, 3 days apart, from 06:00 to 19:00 h (GMT + 1) with a standard clinical thermometer. The treated pullets were administered individually with the vitamins orally in water, while the control pullets were given only water. The lowest hourly RT of 40.9 ± 0.04 °C was obtained in treated pullets at 06:00 h, while the highest value of 41.1 ± 0.01 °C was recorded from 17:00 to 19:00 h (P < 0.001). In control pullets, the RT rose significantly from 41.0 ± 0.03 °C at 06:00 h to the maximum value of 41.6 ± 0.04 °C at 15:00 h (P < 0.001). The pullets co-administered with retinol, ascorbic acid and α-tocopherol had consistently lower RT values than those of control pullets, especially during the hot hours of the day, from 13:00 to 17:00 h. It is concluded that co-administration of retinol, ascorbic acid and α-tocopherol, by preventing a rise in body temperature, ameliorated heat stress, and may enhance productivity of pullets reared under unfavourable, thermal environment conditions.

Association of heat stress protein 90 and 70 gene polymorphism with adaptability traits in Indian sheep (Ovis aries)

Heat stress proteins assist cellular proteins in the acquisition of native structure. The present research was conducted to study how thermo-tolerance is modulated by HSP90 and HSP70 gene polymorphism and its association with hemato-physio-biochemical parameters, supported by their expression profiles in Chokla, Magra, Marwari, and Madras Red sheep breeds. Least square analysis revealed significant effect (P < 0.05) of season and breed on all the physiological parameters, i.e., temperature, respiratory rate, and pulse rate (a.m. and p.m.), as well as hematological parameters like Hb, packed cell volume, total erythrocyte count (TEC), neutrophil/lymphocyte (N/L) ratio, and total leukocyte count (TLC). There was a significant influence (P < 0.05) of breed on biochemical parameters such as glucose, SGOT, phosphorous, triglyceride, and cholesterol. Eight fragments were amplified and sequenced in HSP90, and 70 genes and 13 single-nucleotide polymorphisms (SNPs) were identified. Tetra-primer amplification refractory mutation system PCR, PCR-RFLP, and allele-specific PCR genotyping protocols were developed for large-scale genotyping of five SNPs. A significant difference (P < 0.05) of rectal temperature (a.m.), respiratory rate (p.m.), triglyceride, and total protein was observed at SNP01; albumin at SNP2; pulse rate (p.m.) at SNP3; and rectal temperature (p.m.), pulse rate (p.m.), Hb (g/dL), and N/L ratio at SNP4 and TLC at SNP5. Gene expression analysis revealed higher expression in less adapted animals with Madras Red < Magra < Chokla < Marwari expression pattern [corrected]. Predominant allele was found to be superior in most of the SNPs (SNP1-4) indicating the selection acting in directional manner (positive selection). Finally, it is concluded that TACCA haplotype combination of SNP1-SNP2-SNP3-SNP4-SNP5 might be of some selection advantage for the identification of animals more adaptable to heat stress.

[Aortic Stenosis Combined with Cold Agglutinin Disease]

Cardiac surgery on a patient with cold agglutinin disease is high risk for thromboembolism due to hypothermia perioperative. A 75-year-old woman with cold agglutinin disease underwent aortic valve replacement for severe aortic stenosis. Cold antibody was detected by preoperative screening test for blood transfusion. In order to prevent thromboembolic event during the operation, we maintained rectal temperature at around 36 degrees centigrade during the cardiopulmonary bypass by warming blood in the bypass circuit. Furthermore, antegrade warm blood cardioplegia was injected intermittently for keeping cardiac arrest. There was no thromboembolic event perioperatively.

Effects of L-glutamine on rectal temperature and some markers of oxidative stress in Red Sokoto goats during the hot-dry season

The experiment investigated the ameliorative effects of L-glutamine administration on rectal temperature (RT), erythrocyte osmotic fragility (EOF), serum antioxidant enzyme activities and malondialdehyde (MDA) concentration in Red Sokoto goats during the hot-dry season. Twenty eight healthy Red Sokoto goats, comprising 14 experimental (administered 0.2 g/kg of L-glutamine dissolved in 10 mL of distilled water, once daily for 21 days) and 14 control (administered equivalent of distilled water) goats served as subjects. Rectal temperature (measured at 6:00, 13:00 and 18:00 h) and blood samples (taken at 8:00 h) were obtained from all subjects weekly, before, during and after L-glutamine administration. Data obtained were compared using one-way repeated-measures ANOVA, followed by Tukey's post-hoc test. The dry-bulb temperature, relative humidity and temperature-humidity index for the study period ranged between 24.0 and 37.5 °C, 26.0 and 84.0% and 73.0 and 86.3, respectively. L-glutamine administration decreased (P < 0.05) RT, EOF and MDA and increased superoxide dismutase (SOD) activity in experimental group, compared to controls during weeks 1, 2 and 3. Glutathione peroxidase (GPx) and catalase activities were higher (P < 0.05) in the experimental group than in the controls only during week 1 of L-glutamine administration. In conclusion, L-glutamine administration mitigated increases in RT, EOF and serum MDA concentration and enhanced serum SOD, GPx and catalase activities and may be beneficial in heat-stressed goats during the hot-dry season.

Integrating a human thermoregulatory model with a clothing model to predict core and skin temperatures

This paper aims to integrate a human thermoregulatory model with a clothing model to predict core and skin temperatures. The human thermoregulatory model, consisting of an active system and a passive system, was used to determine the thermoregulation and heat exchanges within the body. The clothing model simulated heat and moisture transfer from the human skin to the environment through the microenvironment and fabric. In this clothing model, the air gap between skin and clothing, as well as clothing properties such as thickness, thermal conductivity, density, porosity, and tortuosity were taken into consideration. The simulated core and mean skin temperatures were compared to the published experimental results of subject tests at three levels of ambient temperatures of 20 °C, 30 °C, and 40 °C. Although lower signal-to-noise-ratio was observed, the developed model demonstrated positive performance at predicting core temperatures with a maximum difference between the simulations and measurements of no more than 0.43 °C. Generally, the current model predicted the mean skin temperatures with reasonable accuracy. It could be applied to predict human physiological responses and assess thermal comfort and heat stress.

[Effects of different training methods for palpation per rectum of internal genital organs on learning success and self-evaluation of students]

Large animal veterinary practice is more and more emphasizing herd-health-management. Processes to ensure and optimize economic viability of dairy farming are becoming more important in comparison to treatment of single ill animals. Amongst others, rectal palpation skills are crucial for proper fertility management, rapid and correct diagnosis of early pregnancies, and recognition of cycle or fertility problems. The aim of this study was first to objectively analyse the effectiveness of prevailing teaching methods for rectal palpation of the reproductive tract during the students' "agricultural internship." Simultaneously, the effectiveness of the use of two teaching simulators prior to the first hands-on experience with live animals was compared with proving just theoretical instruction. The results showed that students acted with more confidence when they were trained in groups of three to five. In particular, the subjective as well as the objective training success was greater for those students, who trained with a simulator (Haptic Cow®, Breed'n Betsy®) than for those who only had theoretical training. Furthermore simulator training resulted in a more realistic student assessment of performance, as well as in a better understanding of where reproductive structures were located (cervix, uterus) in live animals. No significant difference in effect of training was found between the different simulators used here. The results of this study suggest that it is in the interest, not only of students but also of the animals, that simulator training occurs before exercises are performed on living animals.

Concepts of the rectovaginal septum: implications for function and surgery

INTRODUCTION

In the pelvis, the rectogenital septum (RGS) separates the urogenital compartment from the digestive compartment. In men, it corresponds to Denonvilliers' rectoprostatic fascia or rectovesical septum (RVS). Its purpose-and, indeed, its existence-are controversial in women. The purpose of this review was to update knowledge about the RGS in women and, in particular, to clarify its relationship to pelvic nerves in order to deduce practical consequences of pelvic surgery and compare it to the RVS in men.

METHODS

A review of the anatomical and surgical literature was undertaken. Evidence for embryological origin, composition, and surgical importance of the RGS in women and men is suggested.

RESULTS

This manuscript presents evidence of the existence of the RGS in both women (rectovaginal septum, RVaS) and men (rectovesical septum, RVS). It originates from the genital structures and extends from the rectogenital pouch to the perineal body. It is composed of connective tissue associated with bundles of smooth muscle cells and has lateral expansions in close contact with neurovascular bundles originating from the inferior hypogastric plexus. During pelvic surgery for carcinoma, preservation of nerve fibers of erectile bodies is necessary if possible. The RGS is thus an important surgical landmark during urogenital sinus surgery, prolapse surgery, and proctectomy in women as well as during proctectomy and prostatectomy in men.

CONCLUSIONS

The RGS is present in women as well as in men, with great similarities between the two sexes. It represents an important surgical landmark during pelvic nerve-sparing surgery.

A coupling system to predict the core and skin temperatures of human wearing protective clothing in hot environments

The aim of this study is to predict the core and skin temperatures of human wearing protective clothing in hot environments using the coupling system. The coupling system consisted of a sweating manikin Newton controlled by a multi-node human thermal model, and responded dynamically to the thermal environment as human body. Validation of the coupling system results was conducted by comparison with the subject tests. Five healthy men wearing protective clothing were exposed to the thermal neutral and high temperature environments. The skin temperatures of seven body segments and the rectal temperatures were recorded continuously. The predictions of core temperatures made by the coupling system showed good agreement with the experimental data, with maximum difference of 0.19 °C and RMSD of 0.12 °C. The predicted mean skin temperatures fell outside of the 95% CI for most points, whereas the difference between the simulated results and measured data was no more than 1 °C which is acceptable. The coupling system predicted the local skin temperatures reasonably with the maximum local skin temperature of 1.30 °C. The coupling system has been validated and exhibited reasonable accuracy compared with the experimental results.

[Not Available]

Neurophysiological studies of anorectal function provide useful information about the integrity of innervation and neuromuscular function. This information helps to understand the pathophysiological mechanisms leading to severe anorectal disorders function, such as fecal incontinence, pelvic floor disorders and dyssynergic defecation. These tests are commonly performed in patients referred to third level medical centers having negative evaluations or no response to conventional therapy. Proper use of these tests may reveal significant new knowledge of the underlying mechanisms that can lead to better management of these disorders. These techniques are complementary to other types of research such as imaging of the pelvic floor. In this review, the most accomplished neurophysiological studies, indications and clinical utility are analyzed. Several techniques are emerging and provide us with a better understanding of the brain-gut interactions.

Rectal temperature changes and oxygen toxicity in dogs treated in a monoplace chamber

Hyperbaric oxygen treatments are increasingly administered to pet dogs, using veterinary-specific monoplace chambers. The basic physiologic responses, chamber performance and oxygen toxicity rates have not yet been evaluated in dogs in a clinical setting. As a result, a series of consecutive 45-minute, 2-atmospheres absolute (atm abs) hyperbaric treatments with 100% oxygen were evaluated in a veterinary rehabilitation center (n = 285). 65 dogs with a mean body weight of 21 ± 15 kg (1.4-71 kg) were treated with an average of four sessions each. The mean rectal temperature of canine patients decreased 0.07 degrees C (0.1 degrees F) during treatments (p = 0.04). Intra-chamber temperature and humidity both increased: +1.0 degrees C (1.7 degrees F, p < 0.0001) and +5.7% (p < 0.0001), respectively. The mean maximal oxygen concentration measured before depressurization of the veterinary-specific commercial chamber was 98.0 ± 0.9%. No strong correlations (r > 0.75) were identified between body weights, body condition scores, maximal oxygen concentrations, starting or ending rectal temperature, chamber humidity and chamber temperature. Oxygen toxicity was not observed during the observational period. Patients were most commonly treated for intervertebral disc disease (n = 16 dogs) and extensive traumatic wounds (n = 10 dogs), which represented a large number of the total study sessions (19% and 16%, respectively).

Anorectal manometric parameters are influenced by gender and age in subjects with normal bowel function

PURPOSE

Anorectal manometry provides objective information about anorectal function, but its results depend on the examiner's skill, the type of equipment, and subject characteristics like age or gender. This single institution, prospective study was performed to investigate the effect of gender and age on the results of anorectal manometry.

METHODS

All included subjects completed a questionnaire to assess their bowel function. The survey included 13 validated questions (eight on constipation and five on incontinence) and was used to exclude subjects with pathological constipation or incontinence. Subjects with normal bowel function underwent anorectal manometry to measure anal sphincter length (ASL), maximum resting pressure (MRP), and maximum squeeze pressure (MSP), and the results were compared by gender and age.

RESULTS

The mean age of the 154 participants (94 male and 60 female) was 59.1 years. ASL was greater in men (4.23 vs. 3.85 cm, p < 0.001). MRP was not significantly different according to gender (p = 0.93), but MSP was higher in men (190.18 vs. 116.49 mmHg, p < 0.001). ASL did not correlate with age (p = 0.707). MRP was inversely related to age in both men (R (2) = 0.152, p < 0.001) and women (R (2) = 0.282, p < 0.001), and MSP only in women (R (2) = 0.210, p < 0.001).

CONCLUSIONS

Anorectal manometric parameters are influenced by gender and age. This should be taken into consideration when interpreting manometric readings in a clinical setting.

The severity of irritable bowel syndrome or the presence of fibromyalgia influencing the perception of visceral and somatic stimuli

BACKGROUND

Fibromyalgia Syndrome (FMS) is a frequent comorbidity in Irritable Bowel Syndrome (IBS) patients with a higher functional bowel disorder severity index (FBDSI). We tested the possibility that mild to severe IBS patients without FMS would have a graduated visceral and somatic perception, and the presence of FMS would further enhance somatic, but conversely attenuate visceral perception.Our aim was to study visceral and somatic sensitivity in mild IBS patients and in severe IBS patients with or without FMS.

METHODS

Eleven mild IBS and 19 severe IBS with and without FMS patients were studied. Somatic and visceral stimuli were applied in each patient by means of electrical stimulations at active and control sites and by means of an electronic barostat in the rectum. Thresholds for discomfort and perception cumulative scores were measured.

RESULTS

Mild and severe IBS patients without FMS demonstrated a significantly lower somatic perception cumulative score than severe IBS patients with FMS at active site. Conversely only severe IBS patients without FMS had significantly lower visceral thresholds for discomfort than mild IBS patients and severe IBS patients with FMS.

CONCLUSIONS

The presence of co-existing FMS or greater FBDSI affects somatic and visceral perception in a graded fashion across IBS patients.

The importance of prostate bed tilt during postprostatectomy intensity-modulated radiotherapy

Variations in rectal and bladder filling can create a tilt of the prostate bed, which generates the potential for a geographic miss during postprostatectomy radiotherapy. The aim of this study is to assess the effect that bladder and rectum filling has on planning target volume angle, to determine a method to assess prostate bed tilt leading to potential geographic miss, and to discuss possible implementation issues. The cone-beam computed tomography images (n = 377) of 40 patients who received postprostatectomy radiotherapy with intensity-modulated radiotherapy were reviewed. The amount of tilt in the prostate bed was defined as the angle change between 2 surgical clips, one in the upper prostate bed and another in the lower. A potential geographic miss was defined as movement of any clip of more than 1cm in any direction or 0.5 cm posteriorly when aligned to bone anatomy. Variations in bladder and rectum size were correlated with the degree of prostate bed tilt, and the rate of potential geographic miss was determined. A possible clinical use of prostate bed tilt was then assessed for different imaging techniques. A tilt of more than 10° was seen in 20.2% of images, which resulted in a 57.9% geographic miss rate of the superior clip. When tilt remained within 10°, there was only a 9% rate of geographic miss. Potential geographic miss of the inferior surgical clip was rare, occurring in only 1.9% of all images reviewed. The most common occurrence when the prostate bed tilt increased by more than 10° was a smaller bladder and larger rectum (6.4% of all images). The most common occurrence when the prostate bed tilt decreased by more than 10° was a larger bladder and smaller rectum (1.3% of all images). Significant prostate bed tilt (>± 10°) occurred in more than 20% of images, creating a 58% rate of geographic miss. Greatest prostate bed tilt occurred when the bladder size increased or reduced by more than 2 cm or the superior rectum size increased by more than 1.5 cm or reduced by more than 1cm from the planned size. Using prostate bed tilt could be an effective measurement for assessing potential geographic miss on orthogonal images if volumetric imaging is unavailable.

[Intraoperative body temperature changes and short-term outcomes of open and minimally invasive esophagectomy]

BACKGROUND

Esophagectomy is a highly invasive procedure, and recently the use of minimally invasive esophagectomy (MIE) via thoracoscopy and laparoscopy increased, since this technique possibly enhances the recovery and outcomes of the patient compared with open esophagectomy (OE). However there is little data about intraoperative changes in body temperature during OE and MIE.

METHODS

We retrospectively investigated the intraoperative body temperature and the postoperative short-term outcomes of patients undergoing OE (n = 33) or MIE (n = 24). The rectal temperature was recorded at 5 time points (at the start of the surgery, 1, 3, and 5 h after the start of the surgery, and at the end of the surgery).

RESULTS

The average body temperature at the start was similar between the OE and MIE groups (36.5 +/- 0.4 vs. 36.6 +/- 0.5 degrees C, P = 0.497). Throughout the surgery, the temperature of the OE group increased to 37.1 +/- 0.6 degrees C, but the temperature in the MIE group decreased to 36.1 +/- 0.8 degrees C. There was no significant difference in 30-day mortality and short-term complications between the two groups.

CONCLUSIONS

Our study showed that the intraoperative temperature during MIE tended to decrease compared with OE, but the short-term outcomes were comparable.

An update on anorectal disorders for gastroenterologists

Gastroenterologists frequently encounter pelvic floor disorders, which affect 10% to 15% of the population. The anorectum is a complex organ that collaborates with the pelvic floor muscles to preserve fecal continence and enable defecation. A careful clinical assessment is critical for the diagnosis and management of defecatory disorders and fecal incontinence. Newer diagnostic tools (eg, high-resolution manometry and magnetic resonance defecography) provide a refined understanding of anorectal dysfunctions and identify phenotypes in defecatory disorders and fecal incontinence. Conservative approaches, including biofeedback therapy, are the mainstay for managing these disorders; new minimally invasive approaches may benefit a subset of patients with fecal incontinence, but more controlled studies are needed. This mini-review highlights advances, current concepts, and controversies in the area.

Comparison of auricular and rectal temperature measurement in normothermic, hypothermic, and hyperthermic dogs

OBJECTIVE

Measurement of rectal temperature is the most common method and considered gold standard for obtaining body temperature in dogs. So far, no study has been performed comparing agreement between rectal and auricular measurements in a large case series. The purpose of the study was to assess agreement between rectal and auricular temperature measurement in normothermic, hypothermic, and hyperthermic dogs with consideration of different environmental conditions and ear conformations.

MATERIALS AND METHODS

Reference values for both methods were established using 62 healthy dogs. Three hundred dogs with various diseases (220 normothermic, 32 hypothermic, 48 hyperthermic) were enrolled in this prospective study. Rectal temperature was compared to auricular temperature and differences in agreement with regard to environmental temperature, relative humidity, and different ear conformations (pendulous versus prick ears) were evaluated using Pearson's correlation coefficient and Bland-Altman analysis.

RESULTS

Correlation between rec- tal and auricular temperature was significant (r: 0.892; p  <  0.01). However, Bland-Altman plots showed an inacceptable variation of values (bias: 0.300 °C; limits of agreement: -0.606 to 1.206 °C). This variation was above a maximal clinical tolerance of 0.3 °C, which was established by experts' opinion (n = 16). Relative humidity had a significant influence (p   =   0.001), whereas environmental temperature did not.

CONCLUSION

Variation between the two methods of measuring body temperature was clinically unacceptable.

CLINICAL RELEVANCE

Although measurement of auricular temperature is fast, simple, and well tolerated, this method provides a clinically unacceptable difference to the rectal measurement.

[Normal values for high-resolution anorectal manometry in a healthy women: effects of age and maternity]

BACKGROUND

High-resolution manometry (HRM) is increasingly used in the evaluation of anorectal disorders. However, the normal values of HRM have not been widely evaluated. Anorectal pressure patterns are known to be possibly influenced by maternity status in women, but the normal values of HRM in parous and non-parous asymptomatic women have not been studied. The aim of the present study was to evaluate, for the first time, the normal values HRM in asymptomatic parous and non-parous women.

METHODS

Sixteen asymptomatic healthy females (age: 18-63 years) were enrolled into this study, and among them, 11 were parous women. HRM was performed using solid-state manometric assembly with 9 circumferential pressure sensors (MMS, Netherlands). Measurements of external and internal anal sphincter pressure at rest, during voluntary contraction and during rectal balloon distension were compared..

RESULTS

In asymptomatic parous women mean external anal sphincter resting pressure (69.9 ± 13.2) was significantly lower then anal pressure (101.2 ± 22.9) in healthy non-parous women. No differences were found between groups in internal sphincter pressure, voluntary contraction or during balloon distension.

CONCLUSIONS

The found difference in resting external sphincter pressure between parous and non-parous women have to be taken in account when HRM is used for evaluation of functional defecatory disorders. Further studies for establishing of normal values of anorectal HRM in larger group of healthy controls are badly needed.

Evaluation of pelvic visceral functions after modified nerve-sparing radical hysterectomy

BACKGROUND

Nerve-sparing radical hysterectomy (NSRH) was developed in an attempt to minimize complications after radical hysterectomy. Since 2008, a modified NSRH-nerve plane-sparing radical hysterectomy (NPSRH) has been developed at the Cancer Hospital, Chinese Academy of Medical Sciences. The aim of this study was to investigate the role of NPSRH in improving postoperative pelvic visceral dysfunctions.

METHODS

Eighty-three patients with International Federation of Gynecology and Obstetrics (FIGO) stage IB1-IIA2 cervical cancer received NPSRH (the study group) from January 2008 to October 2012. One hundred and sixty-six patients who underwent conventional radical hysterectomy (CRH) were randomly selected as the control group. Age, pathological type and stage were matched between the two groups. The safety of surgery was assessed by duration of operation and blood transfusion rate. Postoperative short-term bladder function was analyzed by duration of catheterization. Long-term bladder, anorectal and sexual function were evaluated with questionnaires.

RESULTS

Seventy-eight patients (94.0%) in the NPSRH group and one hundred and sixty patients (96.4%) in the CRH group completed the study. Median follow-up time was 31.9 months and 31.0 months respectively (P = 0.708). There was no significant difference between the two groups in terms of age, body mass index, FIGO stage, pathologic type, preoperative and postoperative therapy (P > 0.05). The blood transfusion rate shared no difference between two groups (P = 0.364). The operation time in the NPSRH group was significantly longer than CRH group (P < 0.01). But the duration of catheterization and hospitalization in the NPSRH group was significantly reduced compared with CRH group (P < 0.01). In addition, the incidence of long-term urinary frequency, urinary incontinence, urinary retention, straining to void, constipation and diarrhea was significantly lower in the NPSRH group (P < 0.05). However, there was no significant difference regarding sexual function (P > 0.05).

CONCLUSIONS

The current evidence indicated that NPSRH improved long-term bladder function compared to CRH. Moreover, it may improve long-term anorectal function as well.

Novel techniques to study colonic motor function in children

Colonic motility is an essential component of normal colonic physiology and it controls essential bodily functions such as stool propulsion, storage, and expulsion. Disordered colonic motility may present with constipation or diarrhea as well as associated symptoms such as bloating, gas, pain, incontinence, and others. In order to assess colonic motor function, practitioners may use studies that either investigate transit time or that evaluate peristaltic activity. Transit time is the result of both the effectiveness of propulsive pressures and the physical characteristics of the stools. Its measurement allows one to quantify the extent and severity of the colonic dysfunction and permits the assessment of response to therapy. Various methods exist to investigate colon transit time and motility. In this review, we will focus on newer techniques for these investigations, including: scintigraphic transit studies, anorectal manometry, colonic manometry, and studies using a wireless motility capsule.

Factors affecting reflex pelvic floor muscle contraction patterns in women with pelvic floor disorders

OBJECTIVE

To explore factors affecting the presence of two reflex pelvic floor muscle contraction (PFMC) patterns in women with pelvic floor disorders.

METHODS

This was a retrospective analysis of pelvic floor ultrasonography and urodynamic data for 667 consecutive symptomatic women with pelvic floor disorders. We identified on ultrasonography the presence or absence of two reflex PFMC patterns, anorectal lift (ARL) and inward clitoral motion (ICM), preceding or occurring during coughing, and evaluated their associations with possible factors affecting reflex PFMC reactivity, including patient demographics, pelvic organ prolapse stages, ultrasonography findings and urodynamic data.

RESULTS

Of the 667 women, 560 (84.0%) clearly demonstrated reflex ARL and 536 (80.4%) demonstrated ICM. There were significant differences in age (P < 0.001), parity (P = 0.033) and menopausal status (P = 0.005) between women with and those without reflex ICM before or during coughing. The multivariable logistic regression model showed that age was the only independent factor associated with presence of reflex ICM (odds ratio, 0.93 (95% CI, 0.88-0.99), P = 0.017). In contrast, no significant differences were noted between women with and without reflex ARL.

CONCLUSIONS

Increasing age is negatively associated with the presence of reflex ICM during coughing in symptomatic women with pelvic floor disorders.

Anus-preserving rectectomy via telescopic colorectal mucosal anastomosis for low rectal cancer: Experience from a Chinese cohort

AIM: To investigate the safety and efficacy of anus-preserving rectectomy via telescopic colorectal mucosal anastomosis (TCMA) for low rectal cancer.

METHODS: From August 1993 to October 2012, 420 patients including 253 males and 167 females with low rectal cancer underwent transabdominal and transanal anterior resection, followed by TCMA. The distance between the anus and inferior margin of the tumor ranged from 5 to 7 cm, and was 5 cm in 6 patients, 6 cm in 127, and 7 cm in 287 patients. Tumor-node-metastasis staging showed that 136 patients had stage I, 252 had stage II and 32 had stage III. Fifty-six patients with T3 or over received preoperative neoadjuvant chemoradiotherapy.

RESULTS: The postoperative follow-up rate was 91.9% (386/420) with a median time of 6.4 years. All 420 patients underwent radical resection. No postoperative death occurred. Postoperative complications included anastomotic leakage in 13 (3.1%) patients and anastomotic stenosis in 7 (1.6%). The local recurrence rate after surgery was 6.2%, the hepatic metastasis rate was 13.2% and the pulmonary metastasis rate was 2.3%. The 5-year survival rate was 74.0% and the disease-free survival rate was 71.0%. Kirwan classification showed that continence was good in 94.4% of patients with stage I when scored 12 mo after resection.

CONCLUSION: TCMA for patients with low rectal cancer leads to better quality of life and satisfactory defecation function, and lowers anastomotic leakage occurrence, and might be one of the safe operative procedures in anus-preserving rectectomy.

In vitro study of acetylcholine and histamine induced contractions in colon and rectum of adult and neonate rats

Contractile mechanisms of different parts of the gut in adult and neonate may not be identical due to developmental processes. The present study was undertaken to investigate acetylcholine (ACh) and histamine induced contractile responses of colon and rectum in adult and neonatal albino rats. Contractile responses were recorded from isolated in vitro preparations. The dose-response curve for ACh (0.001-100 microM) revealed dose dependent increase in contractile responses. A significantly (P < 0.05) greater contractile responses (g/g wet tissue) was observed in rectum as compared to colon. Atropine pretreatment significantly blocked ACh responses in both rectum and colon. The blockade was higher in adult preparations. The dose-response study for histamine (0.001-100 microM) did not show any significant difference between rectum and colon. Histamine (100 microM) induced contractions were significantly (P < 0.05) increased after pretreatment with pheniramine (100 microM) in adult rectum. This potentiating response of pheniramine was absent in neonate rectum. Such effect was also not seen in colon of both adult and neonate. The present investigation indicates that the contractile responses induced by ACh are similar in both adult and neonate, excepting that the blocking effect of atropine in colon was more pronounced in adult as compared to neonate. Further, the results also indicated different mechanism of histamine action in adults and neonates as evidenced by the significant enhancement of contractions by pheniramine only in adult rectum. Therefore, the present results indicate the existence of a different cholinergic and histaminergic activity in adult and neonate as well as in rectal and colonic tissue.

Alterations in prefrontal-limbic functional activation and connectivity in chronic stress-induced visceral hyperalgesia

Repeated water avoidance stress (WAS) induces sustained visceral hyperalgesia (VH) in rats measured as enhanced visceromotor response to colorectal distension (CRD). This model incorporates two characteristic features of human irritable bowel syndrome (IBS), VH and a prominent role of stress in the onset and exacerbation of IBS symptoms. Little is known regarding central mechanisms underlying the stress-induced VH. Here, we applied an autoradiographic perfusion method to map regional and network-level neural correlates of VH. Adult male rats were exposed to WAS or sham treatment for 1 hour/day for 10 days. The visceromotor response was measured before and after the treatment. Cerebral blood flow (CBF) mapping was performed by intravenous injection of radiotracer ([¹⁴C]-iodoantipyrine) while the rat was receiving a 60-mmHg CRD or no distension. Regional CBF-related tissue radioactivity was quantified in autoradiographic images of brain slices and analyzed in 3-dimensionally reconstructed brains with statistical parametric mapping. Compared to sham rats, stressed rats showed VH in association with greater CRD-evoked activation in the insular cortex, amygdala, and hypothalamus, but reduced activation in the prelimbic area (PrL) of prefrontal cortex. We constrained results of seed correlation analysis by known structural connectivity of the PrL to generate structurally linked functional connectivity (SLFC) of the PrL. Dramatic differences in the SLFC of PrL were noted between stressed and sham rats under distension. In particular, sham rats showed negative correlation between the PrL and amygdala, which was absent in stressed rats. The altered pattern of functional brain activation is in general agreement with that observed in IBS patients in human brain imaging studies, providing further support for the face and construct validity of the WAS model for IBS. The absence of prefrontal cortex-amygdala anticorrelation in stressed rats is consistent with the notion that impaired corticolimbic modulation acts as a central mechanism underlying stress-induced VH.

[Nervous regulation of contractile function of the rectum]

Basic systems of autonomic regulation of contractile function of the rectum are presented. Activation of the parasympathetic system has a predominantly stimulatory influence on the contractile function of the rectum. Activation of alpha1-, alpha2- and beta2-adrenergic receptors of the sympathetic nervous system inhibits contractile function of the rectum, and activation of alphal-adrenergic receptors stimulates contractile function of rectum sphinkters. The data about the effect of serotoninergic, purinergic, peptidergic, and nitrergic systems on the contractile function of the rectum are also presented.

[Women with chronic constipation: clinical examination is more important than anorectal function testing]

Chronic constipation is a common disorder, particularly in women and the elderly. Physical examination of patients with constipation should include rectal examination and in women also vaginal examination. The patient is asked to relax, contract and bear down on the pelvic floor during inspection of the anal region as well as during the rectal examination. Patients can be considered to have a hypertonic pelvic floor when they have difficulty in relaxing or no relaxation at all during straining on three consecutive attempts. Physical examination reveals potentially treatable conditions such as a rectocele or pelvic floor hypertonia in 40% of women with chronic constipation. Anorectal manometry and anal endosonography provide little added value to physical examination in women with chronic constipation. Anorectal function testing should be reserved for selected cases.

Effects of various protective clothing and thermal environments on heat strain of unacclimated men: the PHS (predicted heat strain) model revisited

Five protective garments (light summer clothing L, high visibility clothing HV, military clothing MIL, climber coverall CLM and firefighting clothing FIRE) were assessed on eight unacclimated male subjects at two environments: moderate warm environment with high humidity (MWH, 20.0°C, 86% relative humidity) and warm environment with moderate humidity (WMH, 30.0°C, 47% relative humidity). The thermophysiological responses and subjective sensations were reported. The PHS model (ISO7933) was used for predicting thermophysiological responses for each testing scenario. It was found that there were significant differences between clothing FIRE and other clothing on thermal sensation (p<0.05). Significant differences were found on skin humidity sensation between FIRE and L, HV or MIL (p<0.001). The RPE value in FIRE is significantly different with L and HV (p<0.05). In MWH, the post-exercise mean skin temperatures increased by 0.59 and 1.29°C in MIL and CLM. In contrast, mean skin temperatures in L, HV, MIL, CLM and FIRE in WMH increased by 1.7, 2.1, 2.1, 2.8 and 3.3°C, respectively. The PHS model presented good performance on predicted mean skin temperatures in MIL and CLM at the two studied environments. However, the skin temperature prediction with light clothing in WMH was weak. For thick protective clothing, the prediction on rectal temperature was protective. It is thus concluded that the results generated by the PHS model for high insulating clothing and measurements performed in high humidity environments should be explained with caution.

[Repeatability of measurements of the rectal temperature and comparison of vaginal and rectal temperature in puerperal sows]

OBJECTIVE

Postpartum diseases of sows are economically important in the pig industry. They affect animal health and welfare of sows and piglets. Measuring rectal temperature in sows post partum is a commonly used diagnostic method to early detection of infectious diseases. The study consisted of five parts. The objective of the first four parts was to evaluate the influence of different factors on the measurements of rectal temperature (e.g. investigator, thermometer, penetration depth of the thermometer). The secondary objective of this study was to validate the application of a temperature logger to continuously measure vaginal temperature.

MATERIAL AND METHODS

Thirty sows on the first day postpartum were used in the first four parts of the study. Rectal temperature was measured repeatedly by one investigator, by different investigators, with different thermometers and at different penetration depths. For the fifth part of the study 21 sows on the first day postpartum were used. A temperature logger was inserted in the vagina for a duration of 6 hours. Additionally, rectal temperature was measured.

RESULTS

The data showed that rectal temperature can be measured repeatably (mean ± standard deviation = 38.7 ± 0.1 °C, coefficient of variation = 0.2%). Different investigators or thermometers resulted in low differences (0.0 °C and 0.1 °C). The penetration depth of the thermometer influenced the result (difference of 0.4 °C between 5 and 10 cm). Rectal and vaginal temperatures, measured in 21 sows, were highly correlated (r = 0.80, p < 0.01) with a mean difference of 0.3 °C.

CONCLUSION AND CLINICAL RELEVANCE

Rectal temperature measurement can be regarded as a repeatable diagnostic method. The measurement should be standardized (type of thermometer, penetration depth). The measurement of vaginal temperature with a data logger in early puerperal sows is a possible means for a continuous and non-invasive monitoring of body temperature.

Simulation-based joint estimation of body deformation and elasticity parameters for medical image analysis

Estimation of tissue stiffness is an important means of noninvasive cancer detection. Existing elasticity reconstruction methods usually depend on a dense displacement field (inferred from ultrasound orMR images) and known external forces.Many imaging modalities, however, cannot provide details within an organ and therefore cannot provide such a displacement field. Furthermore, force exertion and measurement can be difficult for some internal organs, making boundary forces another missing parameter. We propose a general method for estimating elasticity and boundary forces automatically using an iterative optimization framework, given the desired (target) output surface. During the optimization, the input model is deformed by the simulator, and an objective function based on the distance between the deformed surface and the target surface is minimized numerically. The optimization framework does not depend on a particular simulation method and is therefore suitable for different physical models. We show a positive correlation between clinical prostate cancer stage (a clinical measure of severity) and the recovered elasticity of the organ. Since the surface correspondence is established, our method also provides a non-rigid image registration, where the quality of the deformation fields is guaranteed, as they are computed using a physics-based simulation.

[Usefulness of a noncontact continuous tympanic thermometer in patients undergoing cardiac surgery using an artificial heart-lung machine]

BACKGROUND

Most of the thermometers used during operations are invasive and non-hygienic. The usefulness of a noncontact continuous tympanic thermometer under general anesthesia has been reported. We evaluated the usefulness of a noncontact continuous tympanic thermometer in patients undergoing cardiac surgery using an artificial heart-lung machine.

METHODS

Twenty patients scheduled to undergo cardiac surgery using an artificial heart-lung machine were selected for this study. After induction of general anesthesia, thermistor probes were inserted into the rectum and esophagus for measurements of rectal and esophageal temperatures, respectively. A noncontact continuous tympanic thermometer was inserted into the ear canal on the right side. These temperatures were monitored and recorded at one-minute intervals. Regression analysis and Bland-Altman analysis were used to compare the data (tympanic/rectal temperatures) with esophageal temperature as a core temperature.

RESULTS

Tympanic temperature showed a good correlation with esophageal temperature (r=0.983, P<0.05). Rectal temperature also showed a good correlation with esophageal temperature (r=0.923, P<0.05), but the coefficient of correlation was low compared to that of tympanic temperature. The mean difference between tympanic temperature and esophageal temperature was -0.022 degrees C, and standard deviation (SD) was 0.395 degrees C. The mean difference between rectal temperature and esophageal temperature was -0.299 degrees C, and standard deviation (SD) was 0.838 degrees C.

CONCLUSIONS

A noncontact continuous tympanic thermometer is useful for measurement of core temperature during cardiac surgery using an artificial heart-lung machine.

Defecation 2: Internal anorectal resistance is a critical factor in defecatory disorders

BACKGROUND

The aim of this study was to test our hypothesis that the reason why imaging is of little assistance in diagnosing "constipation" causes may be related to the high sensitivity of internal anorectal flow resistance in defecation to small changes in geometry. We applied a mathematical model to describe the effects on flow mechanics of observed changes in the shape of the rectum and anus during defecation.

METHODS

Three groups of patients were studied with video proctograms. Group 1 comprised 4 patients with normal defecation studied with video proctography or magnetic resonance imaging (MRI). Group 2 comprised 8 patients with fecal incontinence, studied by video X-ray electromyography. Group 3 comprised 8 patients with constipation evaluated by video MRI.

RESULTS

Three muscle vectors open the anorectal angle prior to defecation, causing the anorectal luminal diameter to increase to approximately twice its resting size. These vectors are forwards (anterior wall), backwards and downwards (posterior wall). Resistance to passage of a fecal bolus through the anorectum is determined by viscous friction against the anorectal wall and by the energy required to deform the bolus as it flows. The observed changes in anorectal geometry serve to reduce both the viscous friction in the anus and the deformation of the bolus, which reduces the force required to facilitate its passage through the anus. For example, if the effective diameter of the anus is doubled during defecation, the frictional resistance is reduced by a factor of 8.

CONCLUSIONS

The sensitivity of flow resistance to geometry explains why MRI or computed tomography (CT) scans taken during defecation are not often helpful in diagnosing causation. Small changes in geometry can have a disproportionate affect on flow resistance. Combining accurate directional measurements during dynamic MRI or CT scans taken during defecation with observations of bolus deformation, and if possible, simultaneous anorectal manometry, may provide clinically helpful insights on patients with anorectal evacuation disorders.

The physiology of human defecation

Human defecation involves integrated and coordinated sensorimotor functions, orchestrated by central, spinal, peripheral (somatic and visceral), and enteric neural activities, acting on a morphologically intact gastrointestinal tract (including the final common path, the pelvic floor, and anal sphincters). The multiple factors that ultimately result in defecation are best appreciated by describing four temporally and physiologically fairly distinct phases. This article details our current understanding of normal defecation, including recent advances, but importantly identifies those areas where knowledge or consensus is still lacking. Appreciation of normal physiology is central to directed treatment of constipation and also of fecal incontinence, which are prevalent in the general population and cause significant morbidity.

Chronic psychosocial stress induces visceral hyperalgesia in mice

Experimental and clinical evidence has shown that chronic stress plays an important role in the onset and/or exacerbation of symptoms of functional gastrointestinal disorders. Here, we aimed to investigate whether exposure to a chronic and temporally unpredictable psychosocial stressor alters visceral and somatic nociception as well as anxiety-related behaviour. In male C57BL/6J mice, chronic stress was induced by repeated exposure to social defeat (SD, 2 h) and overcrowding (OC, 24 h) during 19 consecutive days. Visceral and somatic nociception was evaluated by colorectal distension and a hot plate, respectively. The social interaction test was used to assess social anxiety. Mice exposed to psychosocial stress developed visceral hyperalgesia and somatic hypoalgesia 24 h following the last stress session. SD/OC mice also exhibited social anxiety-like behaviour. All these changes were also associated with physiological alterations, measured as a decreased faecal pellet output and hypothalamic-pituitary-adrenal (HPA) axis disruption. Taken together, these data confirm that this mouse model of chronic psychosocial stress may be useful for studies on the pathophysiological mechanisms underlying such stress-associated disorders and to further test potential therapies.