Cooling-induced gastrointestinal smooth muscle contractions in the rat

Laparoscopic small bowel length measurement: nonassociative nature of total small bowel length with anthropometric and clinical characteristics in patients undergoing bariatric surgery

BACKGROUND

Small bowel length (SBL) may have an impact on the outcomes of bariatric surgeries, but it can be difficult to make a direct association between SBL and the safety and outcome of bariatric surgeries.

OBJECTIVES

To address this issue, we set out to devise a predictive model for SBL determination based on clinical and anthropometric variables.

SETTING

An academic tertiary medical center.

METHODS

Anthropometric and clinical data, including age, sex, height, weight, and past medical history, were collected upon enrollment. SBL was measured twice during the surgery using a marked grasper. In all cases, measurements were carried out by a single surgeon. To create a predictive model, a 2-step approach was employed. In the first step, linear regression was used to determine influential variables. In the second step, all variables with a P value < .2 were entered into a multivariate regression model.

RESULTS

Overall, 961 bariatric candidates were enrolled. The mean age of the participants was 40.08 years, and 77.5% (n = 745) were female. The mean SBL was 748.90 centimeters. There was a weak but statistically significant positive correlation between SBL with both weight and height. Our univariate linear model determined only anthropometric parameters as a predictor of SBL. The multivariate model also yielded that none of the entered parameters were shown to be accurate predictors of SBL. Moreover, only 4.3% of variances were explainable by this model.

CONCLUSION

Although we found a weak positive association between height and SBL, this association lacked clinical practicality.

Spasmolytic Activity of 1,3-Disubstituted 3,4-Dihydroisoquinolines

This article concerns the spasmolytic activities of some novel 1,3-disubstituted 3,4-dihydroisoquinolines. These compounds can be evaluated as potential therapeutic candidates according to Lipinski's rule of five, showing high gastrointestinal absorption and the ability to cross the blood-brain barrier, which is a very important parameter in the drug discovery processes. In silico simulation predicted smooth muscle relaxant activity for all the compounds. Since smooth muscle contractile failure is a characteristic feature of many disorders, in the current paper, we concentrate on the parameters of the spontaneous contractile responses of smooth muscle (SM) cells compared to the well-known drug mebeverine. Two of the newly synthesized substances can be identified as essential modulating regulators and potentially used as therapeutic molecules. One of these molecules also showed significant DPPH antioxidant activity compared to rutin.

Application of response surface methodology (RSM) for optimization of the supercritical CO2 extract of oil from Zanthoxylum bungeanum pericarp: Yield, composition and gastric protective effect

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Supercritical carbon-dioxide (SC-CO₂) extract is an effective technology for flavor components of Z. bungeanum pericarp.

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About 11.07 % oil yield can be obtained under the optimized parameters of 30 MPa, 43 °C, and 75 min.

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Limonene, linalool, hydroxy-α-sanshool and hydroxy-β-sanshool are the major flavor components of SZB.

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SZB supplementation could be employed as a gastric protective agent/additive for human health.

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Nineteen potential biomarkers were identified as the potential biomarkers contributed to the gastric protective effect of SZB.

Supercritical carbon-dioxide (SC-CO₂) is a promising two-phase technology for flavor components (volatile oil and alkylamides) extract from Zanthoxylum bungeanum pericarp. However, the gastric protective effect of SC-CO₂ extract from Z. bungeanum (SZB) have not been systematically investigated. In this study, response surface methodology (RSM) was employed to optimize the yield of SZB, and the average yield of 11.07 % were obtained under optimal parameters (30 MPa, 43 °C and time 75 min). Here, limonene, linalool and hydroxy-α-sanshool were identified as the main compounds of SZB by GC–MS and UPLC-Q-Extractive Orbitrap/MS analysis. When the gastric protective effect of SZB (5, 10 and 20 mg/kg, p.o.) were evaluated, significant increase in body weight and organ indexes of rat, and decreased gastric lesion were observed. Furthermore, nineteen serum metabolites were regarded as the potential biomarkers for the gastric protective effect of SZB. Collectively, this study provides a comprehensive perspective into the chemical composition analysis and gastric protective effect of Z. bungeanum SC-CO₂ extract.

Hypothermia induces opposite response in vascular and non-vascular smooth muscles

BACKGROUND AND AIM

The mechanism of cooling-induced response of smooth muscles remains little understood despite the increasing importance given to it in recent years. The aim of this study was to examine the possibility of releasing a relaxant or a contractile substance during cooling from vascular and non-vascular smooth muscles.

METHODS

Assessing the effect of cooling for two different smooth muscles together, vascular (aorta or carotid) which induced relaxation, and non-vascular (jejunum or bladder) which induced contraction. Hanging a pair of smooth muscle strips from different body organs in the same organ bath filled with Krebs solution, each strip was connected to its own transducer and recorder and stepwise cooling was applied. Recordings of isometric tension using organ-bath techniques.

RESULTS

Step-wise cooling (37 °C-4 °C) of aorta and carotid smooth muscle preparations induced reproducible graded relaxation while jejunum and bladder preparations induced reproducible graded tonic contractions, inversely proportional to temperature. The responses of all the smooth muscle preparations were the same magnitude either alone or as a pair in the organ bath. Cooling abolished rhythmic smooth muscle activity of jejunum and bladder. Cooling-induced contraction was reduced by incubation in Ca²⁺-free solution. The effect of cooling either relaxation or contraction was not enhanced or attenuated by the presence of the two different smooth muscles with opposite response in the same organ bath, proving the absence of a relaxant or a contractile substance released during cooling.

CONCLUSIONS

Cooling of aorta and carotid artery induced relaxation while jejunum and bladder induced contraction. The response to cooling is inversely proportional to the temperature. There was neither a relaxant nor a contractile substance released from vascular or non-vascular smooth muscles during cooling. Our study suggested that the effect of cooling is through a thermal receptor with two subtype one in the vascular smooth muscle (deep blood vessels) which induces relaxation, and the second in non-vascular smooth muscles (non-vascular organs) that induces contraction and the responses depend on extracellular calcium.

Effect of pregnancy on cooling tone and rhythmic contractions of the rat urinary bladder

OBJECTIVES

Pregnancy is a physiological alteration that can affect urinary bladder. Cooling of urinary bladder smooth muscle is known as a potent stimulus to micturition due to an increase in muscle tone. The current study investigates the effects of pregnancy on cooling tone and on the rhythmic contractions of the urinary bladder.

METHODS

Twenty-four rats were used in this study as control group (non-pregnant) and pregnant group (18-20-day pregnancy). Isolated rat urinary muscle strips were suspended in organ baths containing Krebs' solution for isometric tension recording.

RESULTS

Cooling from 37 to 5 °C induced a rapid and reproducible increase in basal tone, proportional to cooling temperature. Cooling also increased the rhythmic activity (amplitude and frequency) at 30 and 25 °C, then decreased at 20 °C, and abolished at 15-5 °C. These responses were more pronounced in pregnant group than in control group. Rhythmic contractions were abolished in calcium-free, EGTA (1 mM)-containing Krebs' solution and in the presence of nifedipine, while they were not affected by CPA or TTX in both groups. Our investigation showed that the influx of extracellular calcium is important in inducing the rhythmic contractions.

CONCLUSIONS

Pregnancy increases cooling-induced contraction in pregnant rat urinary preparations and its rhythmic contractions including amplitude and frequency than non-pregnant rat. Rhythmic contractions are myogenic in nature and highly extracellular calcium dependent. They may play a crucial role in urinary bladder overactivity and incontinence during pregnancy.

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10(-5) M). At 37°C, HCMSs developed a stable phasic contraction (~0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca(2+) concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.

Temperature can influence gastric accommodation and sensitivity in functional dyspepsia with epigastric pain syndrome

BACKGROUND

Functional dyspepsia-epigastric pain syndrome (FD-EPS) is characterized pathophysiologically by visceral hypersensitivity, but the effect of the temperature stimulation on gastric function has been seldom studied.

AIM

The purpose of this study was to investigate the effects of liquid nutrients at different temperatures on the gastric accommodation, sensitivity, and gastric-wall compliance of healthy subjects (HS) and FD-EPS patients.

METHODS

Ten FD-EPS patients (Roma III criteria) and ten HS were recruited into the study. Intragastric pressure (IGP) and gastric perfusion were measured and compared following the administration of liquid nutrients at 37 °C on day 1 and at 8 °C on day 2.

RESULTS

Seven patients developed abdominal discomfort or abdominal pain after being given cold liquid nutrient. The administration of liquid nutrient at 8 °C resulted in an increase of IGP in HS (P=0.044), a significant decrease in gastric perfusion (P<0.0001), a marked increase in IGP (P=0.015), and a dramatic reduction in gastric wall compliance (P=0.012) in patients compared to the effects of liquid nutrient at 37 °C. In addition, IGP in patients was lower than that in HS at 37 °C liquid nutrient (P=0.036), and the gastric perfusion volume in patients at maximal satiety was also significantly reduced at 8 °C liquid nutrient compared with HS (P=0.017).

CONCLUSIONS

Cold stimulation can increase the IGP in HS and FD-EPS patients, elevate the visceral sensitivity and reduce the gastric volume of FD-EPS patients. FD-EPS patients who are sensitive to cold may develop epigastric discomfort or pain.

Response of esophagus to high and low temperatures in patients with achalasia

Background/Aims

Achalasia patients would feel exacerbated dysphagia, chest pain and regurgitation when they drink cold beverages or eat cold food. But these symptoms would relieve when they drink hot water. Reasons are unknown.

Methods

Twelve achalasia patients (mean age, 34 ± 10 years; F:M, 3:9) who never had any invasive therapies were chosen from Peking Union Medical College Hospital. They were asked to fill in the questionnaire on eating habits including food temperature and related symptoms and to receive high-resolution manometry examination. The exam was done in 2 separated days, at swallowing room temperature (25℃) then hot (50℃) water, and at room temperature (25℃) then cold (2℃) water, respectively. Parameters associated with esophageal motility were analyzed.

Results

Most patients (9/12) reported discomfort when they ate cold food. All patients reported no additional discomfort when they ate hot food. Drinking hot water was effective in 5/8 patients who ever tried to relieve chest pain attacks. On manometry, cold water increased lower esophageal sphincter (LES) resting pressure (P = 0.003), and prolonged the duration of esophageal body contraction (P = 0.002). Hot water decreased LES resting pressure and residue pressure during swallow (P = 0.008 and P = 0.002), increased LES relaxation rate (P = 0.029) and shortened the duration of esophageal body contraction (P = 0.003).

Conclusions

Cold water could increase LES resting pressure, prolong the contraction duration of esophageal body, and exacerbate achalasia symptoms. Hot water could reduce LES resting pressure, assist LES relaxation, shorten the contraction duration of esophageal body and relieve symptoms. Thus achalasia patients are recommended to eat hot and warm food and avoid cold food.

Cooling-induced contraction of the rat gastric fundus: mediation via transient receptor potential (TRP) cation channel TRPM8 receptor and Rho-kinase activation

1. Cooling has been shown to induce contractions of several smooth muscles in vitro. However, the mechanism involved in the response is not yet known. In the present study, we investigated the possible involvement of transient receptor potential (TRP) cation channel TRPM8 receptors and the Rho-kinase pathway in cooling-induced contraction of the rat fundus. 2. Cooling-induced contractions were inversely proportional to temperature. Contractions were significantly reduced (by 65.6 +/- 2.4%; P < 0.05) in a Ca2+-free (1 mmol/L EGTA) medium, but were not significantly inhibited by nifedipine (10(-6) mol/L). 3. Capsazepine (3 x 10(-6) and 3 x 10(-5) mol/L), a TRPM8 receptor antagonist, inhibited cooling-induced contraction of the rat gastric fundus. 4. The Rho-kinase inhibitor Y-27632 concentration-dependently inhibited cooling-induced contraction of the gastric fundus, producing approximately 90% inhibition at a concentration of 10(-5) mol/L. Contractions were also inhibited by genistein (3 x 10(-5) mol/L), a tyrosine kinase inhibitor, but not by GF 109203X (10(-7) mol/L), a protein kinase C inhibitor. 5. Using reverse transcription-polymerase chain reaction techniques, it was observed that the mRNA for the TRPM8 receptor and Rho-kinase were expressed in the rat gastric fundus. 6. These results would suggest that cooling-induced contraction of the rat fundus is mediated by activation of TRPM8 receptors via a mechanism involving activation of Rho-kinase.

Rate dependency and role of nitric oxide in the vascular response to direct cooling in human skin

Local cooling of nonglabrous skin without functional sympathetic nerves causes an initial vasodilation followed by vasoconstriction. To further characterize these responses to local cooling, we examined the importance of the rate of local cooling and the effect of nitric oxide synthase (NOS) inhibition in intact skin and in skin with vasoconstrictor function inhibited. Release of norepinephrine was blocked locally (iontophoresis) with bretylium tosylate (BT). Skin blood flow was monitored from the forearm by laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was calculated as the ratio of LDF to blood pressure. Local temperature was controlled over 6.3 cm2 around the sites of LDF measurement. Local cooling was applied at -0.33 or -4 degrees C/min. At -4 degrees C/min, CVC increased (P < 0.05) at BT sites in the early phase. At -0.33 degrees C/min, there was no early vasodilator response, but there was a delay in the onset of vasoconstriction relative to intact skin. The NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (intradermal microdialysis) decreased (P < 0.05) CVC by 28.3 +/- 3.8% at untreated sites and by 46.9 +/- 6.3% at BT-treated sites from the value before infusion. Rapid local cooling (-4 degrees C/min) to 24 degrees C decreased (P < 0.05) CVC at both untreated (saline) sites and L-NAME only sites from the precooling levels, but it transiently increased (P < 0.05) CVC at both BT + saline sites and BT + L-NAME sites in the early phase. After 35-45 min of local cooling, CVC decreased at BT + saline sites relative to the precooling levels (P < 0.05), but at BT + L-NAME sites CVC was not reduced below the precooling level (P = 0.29). These findings suggest that the rate of local cooling, but not functional NOS, is an important determinant of the early non-adrenergic vasodilator response to local cooling and that functional NOS, adrenergic nerves, as well as other mechanisms play roles in vasoconstriction during prolonged local cooling of skin.

Intracavernosal Irrigation by Cold Saline as a Simple Method of Treating Iatrogenic Prolonged Erection

AIMS AND METHODS

The aim of this study was to evaluate the efficacy of aspiration and irrigation of the corpora cavernosa with cold saline as a simple outpatient method for treating prolonged penile erection after intracavernous injection of vasoactive agents.

RESULTS

Aspiration and irrigation was needed in 70 out of 122 cases with iatrogenic priapism in whom cooling of the penis and perineum failed to achieve detumescence. According to the temperature of the saline used, patients were randomized into four different groups: A, B, C, and D with a saline temperature 10, 15, 20, and 37 degrees C, respectively.

MAIN OUTCOME

We used a significantly larger volume of saline in groups C and D compared to group A. On the other hand there was no significant difference in the volume of saline used between groups A and B. Complete detumescence was achieved in 24/25 (96%) of cases in group A compared to 9/15 (60%) of cases in group D.

CONCLUSION

We recommend corporal aspiration and irrigation with 10 degrees C saline for patients with prolonged penile erection who failed to respond to the noninvasive measures using ice-cold compresses and physical exercise.

Role of ERK1/2 in uterine contractility and preterm labor in rats

The present study tested the hypothesis that ERK activation is an essential step in the onset of labor in a rat model of preterm labor. The administration of RU-486, an antiprogesterone agent, to rats induced preterm delivery 22.2 +/- 0.24 h after treatment. Changes in basal signaling events were studied in myometrial tissue from CO(2)-euthanized rats. Rats treated with RU-486 displayed a dramatically increased in vitro uterine contractility compared with gestational stage-matched, sham-treated rats. In vitro contractility was not significantly different from that during spontaneous labor. During RU-486-induced preterm labor, as previously described for spontaneous labor, ERK phosphorylation levels increased, as did phosphorylation of caldesmon at Ser(789), an ERK phosphorylation site. Also, a small but significant increase in 20-kDa myosin light chain phosphorylation was seen at a constant intracellular pCa of 7. When rats were chronically treated with an agent that prevents ERK activation, U-0126, the onset of RU-486-induced preterm labor was delayed in a statistically significant manner. Chronic in vivo treatment with U-0126 also significantly inhibited the RU-486-induced increase in in vitro contractility and ERK and caldesmon phosphorylation but did not alter the RU-486-induced increase in 20-kDa myosin light chain phosphorylation. These data indicate that ERK activation is a component of the multiple events leading to the development of labor in this rat model. We suggest that the ERK pathway could possibly be used to identify targets for the development of a novel class of tocolytic agents.