LncRNA MYLK antisense RNA 1 activates cell division cycle 42/Neutal Wiskott-Aldrich syndrome protein pathway via microRNA-101-5p to accelerate epithelial-to-mesenchymal transition of colon cancer cells

Long noncoding RNA MYLK antisense RNA 1 (MYLK-AS1) is the crux in multiple diseases. Therefore, the purpose of this study was to investigate the possible mechanism of MYLK-AS1. A total of 62 colon cancer (CC) specimens and paired adjacent normal tissues were collected, and the expression of MYLK-AS1, microRNA (miR)-101-5p/cell division cycle 42 (CDC42) was detected. CC cell lines were transfected with MYLK-AS1, miR-101-5p, CDC42-related plasmids, and the biological functions and markers of epithelial-mesenchymal transition (EMT) were analyzed. The binding relationship between MYLK-AS1, miR-101-5p, and CDC42 was evaluated. In CC tissues and cell lines, MYLK-AS1 and CDC42 were highly expressed, and miR-101-5p was lowly expressed. Inhibition of MYLK-AS1 or upregulation of miR-101-5p can inhibit CC cell growth and EMT. miR-101-5p inhibited CDC42/N-wasp axis activation in CC cells by targeting CDC42. Knockdown of CDC42 or upregulation of miR-101-5p partially reversed the effects caused by upregulation of MYLK-AS1. MYLK-AS1, which is significantly upregulated in CC, may be a molecular sponge for miR-101-5p, and MYLK-AS1 promotes the activation of the CDC42/N-wasp axis in CC cells by targeting CDC42 through miR-101-5p, which in turn promotes tumor development. MYLK-AS1 may be a potential biomarker and target for CC therapy.

[Follow-up analysis of sex hormone levels and prognosis in women after hematopoietic stem cell transplantation]

Objective: To investigate the levels of sex hormone and fertility in female patients after hematopoietic stem cell transplantation (HSCT), as well as their correlation with conditioning regimens, and analyse the effect of hormone replacement therapy (HRT) in young women after HSCT. Methods: Retrospective case series study. The clinical data of 147 women who underwent HSCT in the First Affiliated Hospital of Soochow University from January 2010 to January 2021 were retrospectively analyzed. The sex hormone levels were measured and followed-up, and the survival, menstrual fertility and the use of HRT of the patients were also followed-up. The sex hormone levels were measured after transplantation, and the ovarian function was evaluated. Independent sample t test and χ2 test were used for comparison between the two groups. Results: The median age of the 147 patients was 26 (range, 10-45) years. Of them, 135 patients received allogeneic HSCT and 12 patients received autologous HSCT. Furthermore, 129 patients received myeloablative conditioning, and 18 patients received reduced conditioning dose. The median follow-up time was 50 months (range, 18-134 months). Five patients died of disease recurrence during follow-up. Of the 54 patients with subcutaneous injection of zoladex, three recovered menstruation spontaneously after transplantation, and all of them were myeloablative conditioning patients, one patient gave birth to twins through assisted reproductive technology. Ninety-three patients did not use zoladex before conditioning, two patients with aplastic anemia with non-myeloablative transplantation resumed menstruation spontaneously, and conceived naturally. The level of follicle stimulating hormone after transplantation in patients receiving myeloablative conditioning regimen was significantly higher than that in patients receiving reduced-dose conditioning regimen [(95.28±3.94) U/L vs. (71.85±10.72) U/L, P=0.039]. Among 147 patients, 122 patients developed premature ovarian failure, 83 patients received sex hormone replacement therapy after transplantation, and 76 patients recovered menstruation and improved endocrine function. Conclusions: The incidence of premature ovarian failure is high in female patients after HSCT, and patients have a chance at natural conception. Reducing the dose of conditioning regimen and the application of zoladex before transplantation can reduce ovarian of conditioning drugs. HRT after transplantation can partially improve the endocrine function of patients.

[Progress of researches on symbionts in the management of mosquito-borne infectious diseases]

Mosquitoes are the main vectors of many infectious diseases, including malaria and yellow fever, which seriously threaten human health across the world. In addition to the use of chemical insecticides, genetic control is a new attempt to currently available interventions used for mosquito vector control. In terms of ecological safety, however, symbiotic control as a novel approach has been proposed for mosquito control. Since there are multiple symbiotic microflora inhabiting in a variety of tissues of mosquitoes, including the digestive tract, they may affect the transmission of mosquito-borne infectious diseases through affecting the lifespan, reproductive competence, and vector competence of the host. In this review, the interactions between symbionts in mosquitoes were summarized, and the research progress of mosquito-associated symbionts in the management of mosquitoborne infectious diseases was reviewed.

A randomised controlled study on the effects of hernial sac stump fenestration on ultrasound seroma prevention in laparoscopic Type III inguinal hernia repair

Background

The incidence of ultrasound seromas has significantly increased after large hernial sac surgery. Several methods are available for preventing ultrasound seromas, but the clinical results are poor. It has also been demonstrated that hernial sac stump fenestration during laparoscopic incisional hernia repair surgery can significantly decrease the incidence of ultrasound seromas.

Materials and Methods

Ninety patients aged 18-75 years who were treated in our hospital for primary Type III indirect inguinal hernia from March 2017 to March 2018 were randomised to a preventive fenestration group and a control group. All patients underwent transabdominal preperitoneal repair. The number of ultrasound seromas in the inguinal regions and ultrasound seroma volume on day 6 and months 1 and 3 after surgery in the two groups were compared. The secondary outcomes included length of surgery, urinary retention, acute pain, chronic pain, length of hospitalisation, recurrence rate and other complications.

Results

There were no significant differences in demographic characteristics. Ultrasound seroma incidence and ultrasound seroma volume on day 6 and months 1 and 3 after surgery were significantly lower in the preventive fenestration group than that in the control group. There were no significant differences in the length of hospitalisation or incidence of acute pain or urinary retention between the two groups.

Conclusions

Hernial sac stump fenestration after hernial sac transection in inguinal hernia repair surgery is a simple method that can effectively reduce post-operative ultrasound seromas.

MSC-derived exosomal miR-34a/c-5p and miR-29b-3p improve intestinal barrier function by targeting the Snail/Claudins signaling pathway

AIMS

Mesenchymal stem cell (MSC)-derived exosomes (MSCs-exos) regulate biological functions in different diseases, such as liver fibrosis, diabetes, and ischaemic heart injury. However, the function of MSC-derived exosomes on the intestinal barrier and the underlying mechanisms are poorly characterized.

MAIN METHODS

The expression of miR-34a/c-5p, miR-29b-3p and Claudin-3 in human normal intestinal tissues and damaged intestinal tissues was evaluated by RT-qPCR. The effect of MSC-secreted exosomes on Claudins in Caco-2 cells was measured by using confocal microscopy, RT-qPCR and Western blot. Dual luciferase reporter assays and RNA immunoprecipitation (RIP) assays were performed to study the interaction between miR-34a/c-5p, miR-29b-3p and Snail. I/R-induced intestinal damage in rats was used to determine the in vivo effect of MSC-exos on intestinal barrier function.

KEY FINDINGS

In this study, we found that miR-34a/c-5p, miR-29b-3p and Claudin-3 were downregulated in damaged human intestinal tissues. MSC-exos increased the expression of Claudin-3, Claudin-2 and ZO-1 in Caco-2 cells. Further studies demonstrated that MSC-exos promoted Claudin-3, Claudin-2 and ZO-1 expression in Caco-2 cells by Snail, which was targeted by miR-34a/c-5p and miR-29b-3p. In vivo experiments showed that MSC-derived exosomes could improve I/R-induced intestinal damage through the Snail/Claudins signaling pathway.

SIGNIFICANCE

The findings here suggest a novel molecular basis for the therapy of intestinal barrier dysfunction.

Early oral nutrition improves postoperative ileus through the TRPA1/CCK1-R-mediated mast cell-nerve axis

Background

The mechanism of early oral nutrition that regulates the mast cell-nerve axis to improve postoperative ileus (POI) remains unclear. This study aims to investigate whether early oral nutrition can improve POI through Transient receptor potential ankyrin-1 (TRPA1)/cholecystokinin 1 receptor (CCK1-R) in the mast cell-nerve axis.

Methods

Experiment 1: Male Sprague-Dawley (SD) rats were randomly divided into the TRPA1 inhibitor + oral nutrition group (TI + ON + POI), oral nutrition group (ON + POI), POI group (POI) and sham surgery group (Sham). Nine rats in each group were treated. Experiment 2: Primary cultures of mast cells and dorsal root ganglion cells were created, and a non-contact co-culture system was established. The cells were divided into the dorsal root ganglion (DRG) group, mast cell group, DRG + mast cell group, TRPA1 inhibitor or enhancer group, mast cell stabilizer or enhancer group, CCK1-R inhibitor or enhancer group. The results of expression of TRPA1, CCK1-R and histamine in colon tissue, portal vein blood, supernatant or dorsal root ganglia, intestinal transport test and mast cell morphology were analysed.

Results

In experiment 1, Early oral nutrition could alleviate the degranulation and activation of mast cells and alleviate the inflammatory reaction of intestinal wall muscles (P<0.05). Early oral nutrition improved POI by stabilizing mast cells with TRPA1. TRPA1 inhibitor decreased CCK1-R concentrations in portal vein blood and CCK1-R expression in colonic smooth muscle (P<0.05). In experiment 2, the change in mast cell function regulated the secretion of CCK1-R by neurons, CCK1-R negatively regulated the degranulation and activation of mast cells (P<0.05), and mast cells positively regulated the expression of TRPA1 protein in DRG (P<0.05).

Conclusions

Early enteral nutrition can improve POI through the TRPA1/CCK1-R-mediated mast cell-nerve axis. TRPA1 positively regulates CCK1-R to stabilize mast cells, but TRPA1 is not the target of the downstream CCK1-R pathway.

Accuracy of using serum D-dimer for diagnosis of acute intestinal ischemia: A meta-analysis

OBJECTIVE

The purpose of this meta-analysis is to comprehensively assess the accuracy of serum D-dimer for the diagnosis of acute intestinal ischemia.

METHODS

Diagnostic studies of D-dimer for accurate diagnosis of acute intestinal ischemia were extracted from 6 databases, and prospective and retrospective studies that provided adequate data on sensitivity and specificity were included here. Sensitivity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated. The overall diagnostic performance of D-dimer was assessed by plotting a summary receiver operating characteristic curve (SROC) and calculating the area under the curve (AUC).

RESULTS

A total of 1300 patients with suspected acute intestinal ischemia from 12 studies met the inclusion criteria. The combined sensitivity, specificity, PLR, NLR, and DOR were 0.94 (95% CI: 0.87-0.97), 0.50 (95% CI: 0.40-0.61), 1.9 (95% CI: 1.5-2.3), 0.12 (95% CI: 0.05-0.26), and 16 (95% CI: 7-39), respectively. The AUC was 0.81 (95% CI: 0.78-0.84).

CONCLUSION

The results of this meta-analysis suggested that plasma D-dimer detection might be a useful means of identifying patients with acute intestinal ischemia of the abdomen.

Comparison of multi-modal early oral nutrition for the tolerance of oral nutrition with conventional care after major abdominal surgery: a prospective, randomized, single-blind trial

Background & aims

Early oral nutrition (EON) has been shown to improve recovery of gastrointestinal function, length of stay and mortality after abdominal surgery; however, early oral nutrition often fails during the first week after surgery. Here, a multi-modal early oral nutrition program is introduced to promote recovery of gastrointestinal function and tolerance of oral nutrition.

Methods

Consecutive patients scheduled for abdominal surgery were randomized to the multimodal EON group or a group receiving conventional care. The primary endpoint was the time of first defecation. The secondary endpoints were outcomes and the cost-effectiveness ratio in treating infectious complications. The rate of infectious-free patients was regarded as the index of effectiveness.

Results

One hundred seven patients were randomly assigned to groups. Baseline characteristics were similar for both groups. In intention-to-treat analysis, the success rate of oral nutrition during the first week after surgery in the multimodal EON group was 44 (83.0%) versus 31 (57.4%) in the conventional care group (P = 0.004). Time to first defecation, time to flatus, recovery time of bowel sounds, and prolonged postoperative ileus were all less in the multimodal EON group (P < 0.05). The median postoperative length of stay in the multimodal EON group was 8 days (6, 12) versus 10 days (7, 18) in the conventional care group (P < 0.001). The total cost of treatment and nutritional support were also less in the multi-modal early oral nutrition group (P < 0.001). The effectiveness was 84.9 and 79.9% in the multimodal EON and conventional care group, respectively (P = 0.475). However, the cost-effectiveness ratio was USD 537.6 (506.1, 589.3) and USD 637.8 (593.9, 710.3), respectively (P < 0.001).

Conclusion

The multi-modal early oral nutrition program was an effective way to improve tolerance of oral nutrition during the first week after surgery, decrease the length of stay and improve cost-effectiveness after abdominal surgery.

Trial registration

Registration number: ChiCTR-TRC-14004395. Registered 15 March 2014.

Chirality Relay in 2,2'-Substituted 1,1'-Binaphthyl: Access to Propeller Chirality of the Tricoordinate Boron Center

It is a challenging issue to achieve propeller chirality for triarylboranes owing to the low transition barrier between the P and M forms of the boron center. Herein, we report a new strategy to achieve propeller chirality of triarylboranes. It was found that the chirality relay from axially chiral 1,1'-binaphthyl to propeller chirality of the trivalent boron center can be realized when a Me₂ N and a Mes₂ B group (Mes=mesityl) are introduced at the 2,2'-positions of the 1,1'-binaphthyl skeleton (BN-BNaph) owing to the strong π-π interaction between the Me₂ N-bonded naphthyl ring and the phenyl ring of one adjacent Mes group, which not only exerts great steric hindrance on the rotation of the two Mes groups but also gives unequal stability to the two configurations of the boron center for a given configuration of the binaphthyl moiety. The stereostructures of the boron center were fully characterized through ¹ H NMR spectroscopy, X-ray crystal analyses, and theoretical calculations. Detailed comparisons with the analog BN-Ph-BNaph, in which the Mes₂ B group is separated from 1,1'-binaphthyl by a para-phenylene spacer, confirmed the essential role of π-π interaction for the successful chirality relay in BN-BNaph.

Impact of nutritional support that does and does not meet guideline standards on clinical outcome in surgical patients at nutritional risk: a prospective cohort study

Objective

To investigate the impact of nutritional support on clinical outcomes in patients at nutritional risk who receive nutritional support that meets guideline standards and those who do not.

Methods

This prospective cohort study enrolled hospitalized patients from the Second Affiliated Hospital of Kunming Medical University from February 2010 to June 2012. The research protocols were approved by the university’s ethics committee, and the patients signed informed consent forms. The clinical data were collected based on nutritional risk screening, administration of enteral and parenteral nutrition, surgical information, complications, and length of hospital stay.

Results

During the study period, 525 patients at nutritional risk were enrolled in the cohorts. Among patients who received nutritional support that met the guideline standards (Cohort 1), the incidence of infectious complications was lower than that in patients who did not meet guideline standards (Cohort 2) (17.1 % vs. 26.9 %, P = 0.01). Subgroup analysis showed that individuals who received a combination of parenteral nutrition (PN) and enteral nutrition (EN) for 7 or more days had a significantly lower incidence of infectious complications (P = 0.001) than those who received only PN for 7 or more days or those who received nutritional support for less than 7 days or at less than 10 kcal/kg/d. Binary logistic regression analysis showed that, after adjusting for confounding factors, nutritional support that met guideline standards for patients with nutritional risk was a protective factor for complications (OR: 0.870, P < 0.002).

Conclusions

In patients at nutritional risk after abdominal surgery, nutritional support that meets recommended nutrient guidelines (especially regimens involving PN + EN ≥ 7 days) might decrease the incidence of infectious complications and is worth recommending; however, well-designed trials are needed to confirm our findings. Nutritional support that does not meet the guideline standards is considered clinically undesirable.

A highly selective ratiometric bifunctional fluorescence probe for Hg2+and F−ions

A dithioacetal-containing triarylborane behaves as a promising ratiometric bifunctional fluorescence probe to detect Hg²⁺and F⁻simultaneously.

Asiatic acid promotes p21(WAF1/CIP1) protein stability through attenuation of NDR1/2 dependent phosphorylation of p21(WAF1/ CIP1) in HepG2 human hepatoma cells

Previous studies have suggested anti-tumor effects of asiatic acid in some human cancer cell lines. This agent is reported to increase the levels of p21WAF1/CIP1 in human breast cancer cell lines. However, the molecular mechanisms have not been established. Here we report that asiatic acid up-regulates p21WAF1/CIP1 protein expression but not the level of p21WAF1/CIP1 mRNA in HepG2 human hepatoma cells. Furthermore, we found that the asiatic acid induced increase of p21WAF1/CIP1 protein was associated with decreased phosphorylation (ser-146) of p21WAF1/CIP1. Knockdown of NDR1/2 kinase, which directly phosphorylates p21WAF1/CIP1 protein at ser-146 and enhances its proteasomal degradation, increased the levels of p21WAF1/CIP1 protein and eliminated the regulation of p21WAF1/ CIP1 stability by asiatic acid. At the same time, the expression of NDR1/2 kinase decreased during treatment with asiatic acid in HepG2 cells. Moreover, asiatic acid inhibited the proliferation of HepG2 cells, this being attenuated by knockdown of p21WAF1/CIP1. In conclusion, we propose that asiatic acid inhibits the expression NDR1/2 kinase and promotes the stability of p21WAF1/CIP1 protein through attenuating NDR1/2 dependent phosphorylation of p21WAF1/CIP1 in HepG2 cells.

HEPA and PARSE: Systematic discovery of clinically relevant tumor-specific antigens

The effective discovery of tumor-specific antigens (TSAs) holds the key for the development of new diagnostic assays and immunotherapeutic approaches against cancer. Here, we discuss our recently developed technologies, HEPA and PARSE, which allow for the systematic identification of TSAs, generating a reservoir of immunologically and clinically relevant targets.

IQGAP3 promotes EGFR-ERK signaling and the growth and metastasis of lung cancer cells

Proteins of the IQGAP family display complicated and often contradictory activities in tumorigenesis. IQGAP1 has well documented oncogenic potential and IQGAP2 has putative tumor-suppressive function. IQGAP3 is the latest addition to this family and its role in cancer development remains to be defined. Here we demonstrate IQGAP3 expression is markedly increased in lung cancer tissues at both mRNA and protein levels. Overexpression of IQGAP3 promoted tumor cell growth, and migration and invasion, whereas knockdown of IQGAP3 exhibited opposite effects. Moreover, suppression of IQGAP3 in a lung cancer cell line caused a reduction in the tumorigenicity of these cells in lung tissue after intravenous injection. Furthermore, we showed that IQGAP3 is able to interact with ERK1 and enhance its phosphorylation following treatment with EGF. These data suggest that IQGAP3 may contribute to the pathogenesis of lung cancer by modulating EGFR-ERK signaling.

[Determination of the biological attribute of evidence at the scene using reverse transcription PCR and real-time fluorescent quantitative PCR]

OBJECTIVE

To explore the feasibility of biological method to identify the biological attribute of samples at crime scene.

METHODS

Thirty samples of ten blood stains, ten saliva stains and ten semen stains were selected, and all the samples were processed by the routine method and biomolecular method, respectively. Both RNA and DNA were isolated using DNA-RNA co-extraction technology and the mRNA was converted into cDNA using reverse transcription PCR (RT-PCR). Three pairs of specific primers were designed for blood stain, saliva stain and semen stain based on the different target genes in three specific tissues and the primers were amplified using real-time fluorescent quantitative PCR. The differences in these biological samples were evaluated by melting temperature (Tm) values and the size of the amplification fragment.

RESULTS

The Tm values of blood stain, saliva stain and semen stain were (84.5 +/- 0.2) degrees C, (76.9 +/- 0.3) degrees C and (88.5 +/- 0.2) degrees C, respectively. The length of PCR fragments of them was 177bp, 134bp and 294bp, respectively.

CONCLUSION

Compared with the routine method, RT-PCR with real-time fluorescent quantitative PCR is highly specific, sensitive and reliable to identify the biological attribute of evidence, and can be potentially applied to determine evidence attribute in forensic practice.

An integrated genome-wide approach to discover tumor-specific antigens as potential immunologic and clinical targets in cancer

Tumor-specific antigens (TSA) are central elements in the immune control of cancers. To systematically explore the TSA genome, we developed a computational technology called heterogeneous expression profile analysis (HEPA), which can identify genes relatively uniquely expressed in cancer cells in contrast to normal somatic tissues. Rating human genes by their HEPA score enriched for clinically useful TSA genes, nominating candidate targets whose tumor-specific expression was verified by reverse transcription PCR (RT-PCR). Coupled with HEPA, we designed a novel assay termed protein A/G-based reverse serological evaluation (PARSE) for quick detection of serum autoantibodies against an array of putative TSA genes. Remarkably, highly tumor-specific autoantibody responses against seven candidate targets were detected in 4% to 11% of patients, resulting in distinctive autoantibody signatures in lung and stomach cancers. Interrogation of a larger cohort of 149 patients and 123 healthy individuals validated the predictive value of the autoantibody signature for lung cancer. Together, our results establish an integrated technology to uncover a cancer-specific antigen genome offering a reservoir of novel immunologic and clinical targets.

Rapid identification of UCA1 as a very sensitive and specific unique marker for human bladder carcinoma

PURPOSE

The most common genitourinary malignancy in China is bladder transitional cell carcinoma (TCC). Early diagnosis of new and recurrent bladder cancers, followed by timely treatment, will help decrease mortality. There are currently no satisfactory markers for bladder cancer available in clinics. Better diagnostic methods are highly demanded.

EXPERIMENTAL DESIGN

In this research, we have used comprehensive expressed sequence tag analysis, serial analysis of gene expression, and microarray analysis and quickly discovered a candidate marker, urothelial carcinoma associated 1 (UCA1). The UCA1 gene was characterized and its performance as a urine marker was analyzed by reverse transcription-PCR with urine sediments. A total of 212 individuals were included in this study, 94 having bladder cancers, 33 ureter/pelvic cancers, and 85 normal and other urinary tract disease controls.

RESULTS

UCA1 was identified as a novel noncoding RNA gene dramatically up-regulated in TCC and it is the most TCC-specific gene yet identified. The full-length cDNA was 1,439 bp, and sequence analysis showed that it belonged to the human endogenous retrovirus H family. Clinical tests showed that UCA1 assay was highly specific (91.8%, 78 of 85) and very sensitive (80.9%, 76 of 94) in the diagnosis of bladder cancer and was especially valuable for superficial G2-G3 patients (sensitivity 91.1%, 41 of 45). It showed excellent differential diagnostic performance in various urinary tract diseases without TCC.

CONCLUSIONS

UCA1 is a very sensitive and specific unique marker for bladder cancer. It could have important implications in postoperative noninvasive follow-up. This research also highlights a shortcut to new cancer diagnostic assays through integration of in silico isolation methods with translational clinical tests based on RNA detection protocols.

A new crystal form of nateglinide

AIM

To find a new crystal structure of S-form in nateglinide [N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine]. The XRD, IR patterns and data were given and the melting point was determined.

METHODS

Phase analysis was performed by X-ray powder diffraction, IR and elemental analysis and the melting point was determined by differential scan calorimetry.

RESULTS

S-form nateglinide is different from H-form or B-form. The melting point is 172.04 degrees C.

CONCLUSION

The S-form nateglinide is a new crystal form.

Cholesterol inhibits spontaneous action potentials and calcium currents in guinea pig gallbladder smooth muscle

Elevated cholesterol decreases agonist-induced contractility and enhances stone formation in the gallbladder. The current study was conducted to determine if and how the electrical properties and ionic conductances of gallbladder smooth muscle are altered by elevated cholesterol. Cholesterol was delivered as a complex with cyclodextrin, and effects were evaluated with intracellular recordings from intact gallbladder and whole cell patch-clamp recordings from isolated cells. Cholesterol significantly attenuated the spontaneous action potentials of intact tissue. Furthermore, calcium-dependent action potentials and calcium currents were reduced in the intact tissue and in isolated cells, respectively. However, neither membrane potential hyperpolarizations induced by the ATP-sensitive potassium channel opener, pinacidil, nor voltage-activated outward potassium currents were affected by cholesterol. Hyperpolarizations elicited by calcitonin gene-related peptide were reduced by cholesterol enrichment, indicating potential changes in receptor ligand binding and/or second messenger interactions. These data indicate that excess cholesterol can contribute to gallbladder stasis by affecting calcium channel activity, whereas potassium channels remained unaffected. In addition, cholesterol enrichment may also modulate receptor ligand behavior and/or second messenger interactions.

Altered migrating myoelectrical complex in an animal model of cholesterol gallstone disease: the effect of erythromycin

BACKGROUND

The ground squirrel on a high cholesterol diet exhibits prolonged intestinal transit, a pathogenetic factor in cholesterol gallstone formation.

AIMS

To examine the effect of a high cholesterol diet on the characteristics of the migrating myoelectrical complex (MMC) and the potential benefit of erythromycin.

METHODS

Twenty four animals received either a trace (controls) or a 1% (high) cholesterol diet. After four weeks, five bipolar jejunal and terminal ileal electrodes were implanted. Seven days later, myoelectric activity was measured in conscious, fasted animals before and after treatment with erythromycin. Biliary lipid composition was assessed.

RESULTS

Compared with controls, animals fed the high cholesterol diet exhibited a prolonged MMC cycle period (70 (6) versus 83 (3) minutes; p<0.05), whereas MMC migration velocity and the proportions of the MMC represented by phases I, II, and III were unchanged. Oral erythromycin significantly shortened the MMC cycle period in animals on the control and high cholesterol diet by 59% and 54% respectively, and increased the proportion of the cycle period occupied by phase III of the MMC in both dietary groups. Gall bladder bile became saturated with cholesterol and crystals developed in nine of 12 animals on the high cholesterol diet; controls had none.

CONCLUSION

Animals fed a high cholesterol diet had a prolonged MMC cycle period. This, along with diminished gall bladder motility, impairs the enterohepatic cycling of bile salts and reduces their hepatic secretion, contributing to the formation of abnormal bile. Erythromycin initiated more frequent cycling of the MMC. Its therapeutic value in cholesterol gallstone formation warrants further evaluation.

The basis for progesterone impairment of gallbladder contractility in male guinea pigs in vitro

Progesterone suppresses gallbladder smooth muscle function but its exact mechanism is unknown. We sought to determine the cellular site where progesterone impairs gallbladder smooth muscle. Sixty-four adult male guinea pigs were injected with either progesterone (2 mg/kg/day sc) or normal saline (controls) for 7 days. Dose-response curves of gallbladder strips to cholecystokinin (CCK), bethanechol, and potassium (K+) were constructed in vitro. To better define the basis for the progesterone effect, gallbladder contractile response was determined to specific agonists: aluminum fluoride and mastoparan (direct G-protein activators), cyclopiazonic acid (CPA), and a calcium ionophore (A-23187). Gallbladder from animals on progesterone exhibited a marked decrease in contractile response to CCK and bethanechol compared with controls (P < 0.05). Further, gallbladder contraction remained depressed (P < 0.05) in progesterone-treated animals, when the G protein was directly activated with aluminum fluoride and mastoparan. In contrast, the responses to K+ (acting independent of receptor G-protein) and to A-23187 and CPA (agonists that bypassed the membrane) were comparable in both groups (NS). It is concluded that progesterone directly inhibits gallbladder smooth muscle contractility in vitro to a standard hormone, CCK, and a cholinergic agent. Such depressed contraction is not due to an altered contractile machinery, since it is normal with agonists that act independently of G-protein activation. Progesterone thus interferes with signaling through the G-protein, either by directly becoming closely associated with the cell membrane or by indirectly perturbing its receptor products.

Effect of the prokinetic agent, erythromycin, in the Richardson ground squirrel model of cholesterol gallstone disease

Impaired gallbladder motility and delayed intestinal transit contribute to cholesterol gallstone formation by impeding the enterohepatic circulation of bile salts and causing gallbladder stasis. The therapeutic value of erythromycin, a prokinetic motilin analog, was evaluated in an animal model of gallstone formation. Eighty ground squirrels were fed either a trace- (control) or a high- (1%) cholesterol diet. Half of each diet group received either erythromycin stearate or placebo orally twice daily for 4 weeks. Biliary lipid secretion and bile salt pool size were determined via common duct cannulation. Gallbladder contractile response to cholecystokinin (CCK) was studied in vitro. Intestinal transit was evaluated in vivo by 51Cr marker. In the placebo-treated group, fed the high- versus the trace-cholesterol diet, bile salt secretion decreased (trace-cholesterol + placebo, 21.0 +/- 1.8 nmol/min/g liver vs. high-cholesterol + placebo, 9.3 +/- 1.4 nmol/min/g liver), cholesterol saturation index (CSI) doubled (trace-cholesterol + placebo, 0.61 +/- 0.06 vs. high-cholesterol + placebo, 1.30 +/- 0.04), nucleation time shortened (trace-cholesterol + placebo, > 21 days vs. high-cholesterol + placebo, 6.4 +/- 1.0 days), cholesterol crystals formed, gallbladder contractility diminished, and intestinal transit was delayed (each P < .05). Erythromycin treatment of animals on the high-cholesterol diet restored gallbladder contractility and intestinal transit to control levels, increased bile salt secretion, reduced the total bile salt pool, lowered the cholesterol saturation of bile, lengthened the nucleation time, and so reduced crystal formation (each P < .05). Erythromycin enhances gallbladder motility and hastens intestinal transit, promoting more rapid enterohepatic cycling of bile salts. This increases bile salt secretion, improves cholesterol solubility, and reduces crystal development.

Sustained gallbladder stasis promotes cholesterol gallstone formation in the ground squirrel

Although gallbladder stasis exists in most patients with cholesterol gallstones, it is unknown whether stasis is a causative factor of gallstone disease or merely a consequence of it. We studied the impact of sustained gallbladder stasis induced by a cholecystokinin (CCK)-A receptor antagonist (MK-329) on gallstone formation in ground squirrels fed either a trace or a high-cholesterol diet. MK-329 markedly inhibited gallbladder contraction in vitro in response to CCK (at EC100, control: 3.6 +/- 0.5 vs. MK-329: 1.1 +/- 0.3 g; P < .05) and increased gallbladder fasting volume in vivo (control: 462 +/- 66 vs. MK-329: 1,004 +/- 121 microL; P < .05). Whereas the high-cholesterol diet alone (1%-cholesterol diet + placebo) increased the cholesterol saturation index (CSI) in control animals (trace-cholesterol diet + placebo), MK-329 significantly (P < .05) decreased the CSI in both hepatic and gallbladder bile in animals on the trace-(trace-cholesterol diet + MK-329) as well as on the high-cholesterol diets (1%-cholesterol diet + MK-329). The mucin content of the mucus layer on the epithelial surface of the gallbladder wall more than doubled (P < .05) with the high-cholesterol diet; adding MK-329 to the latter group produced a further 82% increase (P < .05). The cholesterol diet + MK-329 group had the highest (100%) incidence of cholesterol crystals that were evident in fresh gallbladder bile, coincident with a shortened nucleation time (2.5 +/- 0.6 days; P < .05 vs. the cholesterol diet + placebo group, 5.8 +/- 1.0 days or the other 2 groups, >21 days). Bile from animals on the trace-cholesterol diet, whether or not receiving MK-329, lacked crystals in bile and exhibited a normal nucleation time (>21 days). Thus, stasis per se may lower the CSI, but its detrimental effect on the gallbladder predominates locally, and so accelerates cholesterol crystal formation in this model.

Surgical treatment of solid brain stem tumors in adults: a report of 22 cases

BACKGROUND

Brain stem tumors in adults are infrequent. Most reports of surgical treatment for these tumors involve partial tumor removal in highly selected patients. A more aggressive approach for removing tumors, especially solid and intrinsic ones, has been controversial.

METHODS

Twenty-two adult patients with brain stem tumors were surgically treated. Surgical techniques, potential risks, and selection of appropriate treatment were evaluated.

RESULTS

Tumors were totally or subtotally removed in 20 patients and only partially removed in two patients. Serious complications such as respiratory disturbances and circulatory dysfunction occurred in 10 patients. Eight patients with these complications recovered after appropriate treatments. Upon discharge, most signs and symptoms improved in 17 patients.

CONCLUSION

Most brain stem tumors, except for malignant gliomas and small ventral tumors, are amenable to an aggressive surgical approach. Exophytic medullary tumors that present dorsally comprise the most benign subgroup of brain stem tumors. Total removal can enhance survival, improve the patient's quality of life, and offer a favorable long-term prognosis. Appropriate management of postoperative complications is essential for good results.

Inhibitory effect of bile salts on gallbladder smooth muscle contractility in the guinea pig in vitro

BACKGROUND & AIMS

Impaired gallbladder emptying occurs in patients undergoing bile salt therapy for cholesterol gallstone dissolution and in patients with cirrhosis who have elevated serum bile salt concentrations. To determine if bile salts directly inhibit gallbladder contractility, isometric contraction of the guinea pig gallbladder was examined in vitro.

METHODS

Contractile responses to cholecystokinin (CCK), bethanechol, KCI, and field stimulation were constructed alone and in the presence of selected bile salts: taurodeoxycholate (TDC), taurochenodeoxycholate, taurocholate, and tauroursodeoxycholate (TUDC).

RESULTS

More hydrophobic bile salts, such as TDC (as low as 5 micromol/L), concentration-dependently depressed (P < 0.05) both CCK- and field stimulation-induced gallbladder contractions. More hydrophilic bile salts, such as TUDC, only caused a modest depression up to a concentration of 500 micromol/L. When 5 or 50 micromol/L of TUDC was added to the organ bath before the application of equalmolar TDC, the TDC-induced impaired gallbladder contractility was reversed. Thus, this inhibitory effect on gallbladder contraction depended on the hydrophobicity of bile salts and was also specific for certain stimuli such as CCK and field stimulation (mediated by cholinergic nerves, being abolished by atropine and tetrodotoxin).

CONCLUSIONS

Such direct bile salt inhibition of CCK- and cholinergic nerve-induced gallbladder contraction may contribute to the deteriorating gallbladder emptying in patients undergoing bile salt therapy for stone dissolution and in cirrhotic patients who are at risk for gallstone formation.

Aggressive surgery for intramedullary tumor of cervical spinal cord

BACKGROUND

Intramedullary tumors of the cervical spinal cord are common and many believe they are amenable to an aggressive approach. However, surgical removal of intramedullary tumors of the cervical spinal cord is still controversial because of the great risk of respiratory dysfunction or quadriplegia or both upon resection of the tumor.

METHODS

We present a consecutive series of 58 patients who underwent surgical treatment for intramedullary tumors of the cervical spinal cord. Surgical results are analyzed to refine our indications for surgery and its timing. The roles of preoperative radiotherapy and posttherapeutic cord appearance and function are discussed.

RESULTS

Tumors were totally resected in 50 (86.2%), subtotally in seven and partially in one patient. Forty-five (77.6%) patients had improved neurologic status postoperatively. Intramedullary tumors in the cervical area have better results from surgery than intramedullary tumors in other levels of the spine. Patients with moderate neurologic deficits can recover remarkably well after total tumor removal. Laser surgery is especially helpful for lipoma. Preoperative radiotherapy should be avoided because it is associated with difficult surgery and poor clinical outcome. The thin spinal cord can function surprisingly well.

CONCLUSIONS

We conclude that intramedullary tumors of the cervical spinal cord are amenable to total surgical removal. Surgery is suitable when a patient presents with a moderate neurologic deficit. Proficient surgical technique for total tumor resection is necessary for good results. Preoperative radiotherapy contributes to difficult surgery and poor prognosis, and is not recommended.

Slow intestinal transit: a motor disorder contributing to cholesterol gallstone formation in the ground squirrel

Impaired gallbladder motility is an established factor in cholesterol gallstone formation. We assessed whether altered small intestinal smooth muscle contractility with slow transit might potentiate gallstone formation by further impeding enterohepatic cycling of bile acids. Ground squirrels were fed a 1% or a trace (controls) cholesterol diet. Small intestinal transit was evaluated from 51Cr distribution in conscious, fasted animals 20 minutes after infusion into the proximal jejunum. Small intestinal and gallbladder smooth muscle contractility was determined in vitro. Biliary lipid secretion was measured from the cannulated common duct and the bile salt pool size calculated by isotope dilution. Gas-liquid chromatography (GLC) assessed bile salt profile. In animals on the 1% cholesterol diet, aboral transit was significantly delayed, the maximal contractile response to bethanechol was markedly increased (P <.05) with no change in median effective concentration in either circular or longitudinal muscle strips from both the jejunum and ileum, and the gallbladder contractile responses to bethanechol and cholecystokinin (CCK) were decreased. Cholesterol saturation index and the fraction of deoxycholic acid in the pool doubled, whereas the total bile salt pool size remained unchanged in cholesterol-fed animals. In this model, a high-cholesterol diet is associated with altered small intestinal smooth muscle contractility and prolonged small intestinal transit, in addition to diminished gallbladder contractility. The resulting sluggish enterohepatic cycling of bile salts, associated with expanded deoxycholate pool, contributes to cholesterol gallstone formation.

The potential site of impaired gallbladder contractility in an animal model of cholesterol gallstone disease

BACKGROUND & AIMS

Gallbladder contractility is decreased in cholesterol gallstone disease, but the mechanism underlining this defect is unclear. The aim of this study was to determine the cellular site of this defect in an animal model of cholesterol gallstone disease.

METHODS

Ground squirrels were maintained for 28 days on either a control or a 1% cholesterol diet. Gallbladder contractile responses to several known agonists were measured in vitro using smooth muscle strips.

RESULTS

Gallbladder contractility in response to cholecystokinin, bethanechol, and K+ was equally decreased in cholesterol-fed animals, in concert with an increased cholesterol saturation of gallbladder bile compared with controls. In contrast, the contractile responses to A-23187 (a calcium ionophore), cyclopiazonic acid (a selective, potent inhibitor of sarcoplasmic reticulum Ca2+ pump), and barium (a calcium analogue), which readily diffuse across the intact sarcolemmal membrane, remained the same in both groups. Dose responses to a G-protein activator, aluminum fluoride, were again not different between these two groups.

CONCLUSIONS

The primary smooth muscle defect in this animal model of cholesterol gallstone disease does not reside in the intracellular signal transduction pathways or in the contractile apparatus but instead involves the sarcolemmal membrane.

Inhibition of gallbladder emptying decreases cholesterol saturation in bile in the Richardson ground squirrel

Impaired gallbladder emptying is frequent in cholesterol gallstone disease as well as in predisposing conditions like pregnancy and obesity. Gallbladder hypomotility is considered a pathogenic factor for gallstone formation, providing the residence time for cholesterol crystal nucleation, but any effect on the enterohepatic circulation of bile acids and subsequently on biliary lipid composition is unknown. Therefore, we studied the effect of prolonged suppression of gallbladder emptying with a cholecystokinin (CCK-A) receptor antagonist on bile formation in Richardson ground squirrels fed a trace versus a 1% cholesterol diet. Biliary lipid secretion was measured directly and bile acid pool size assessed by isotope dilution ([14C]-cholic acid). Gallbladder contraction was determined in vitro in response to CCK. The CCK-antagonist (MK-329) greatly inhibited gallbladder contraction in vitro and increased gallbladder fasting volume and bile acid pool size in vivo. It significantly lowered the cholesterol saturation index by 35% and 46% in hepatic bile and by 18% and 28% in gallbladder bile in the trace and cholesterol diet groups, respectively. Bile acid secretion and bile flow doubled with the CCK-receptor antagonist. Chronic CCK receptor antagonist-induced inhibition of gallbladder emptying increases bile acid secretion and thereby decreases cholesterol saturation in bile. Extensive biliary hypomotility thus leads to a more rapid cycling of bile acids by depriving the gallbladder of its function in the enterohepatic circulation.

Magnetic resonance imaging and microsurgical treatment of intramedullary hemangioblastoma of the spinal cord

Thirteen cases of intramedullary hemangioblastoma of the spinal cord are reported. The tumors were diagnosed with radiological studies, especially magnetic resonance imaging. Microsurgery was used to achieve gross total removal of the tumors in all cases. Signs and symptoms improved in 84.6% of the patients after surgery. The authors describe the diagnosis and microsurgical techniques for the excision of intramedullary hemangioblastoma of the spinal cord. This disease should be differentiated from hydromyelia, intramedullary ependymoma, and vascular malformation of the spinal cord. Total removal of the tumor is recommended.

Cisapride improves gallbladder contractility and bile lipid composition in an animal model of gallstone disease

BACKGROUND

The hepatic secretion of supersaturated bile and gallbladder stasis are key events in cholesterol gallstone formation. The therapeutic value of cisapride, a prokinetic agent, was assessed in ground squirrels on a 1% cholesterol diet.

METHODS

Biliary lipid secretion was measured directly and bile salt pool size assessed by isotope dilution ([14C]cholic acid). Gallbladder contraction was measured in vitro in response to cholecystokinin (CCK).

RESULTS

Cholesterol-fed animals had a combined hepatic secretory defect (a 53% decrease in bile salt secretion and also a 31% increase in cholesterol secretion). Adding cisapride restored bile salt secretion to control levels but did not affect cholesterol secretion. In cholesterol-fed animals, the cholesterol saturation index of gallbladder bile more than doubled and cholesterol crystals developed; cisapride markedly reduced cholesterol saturation, thus preventing crystal formation. Gallbladder contractility, measured in vitro in response to CCK, decreased 23% in animals on the 1% cholesterol diet; cisapride restored the CCK dose-response curve to normal. The bile salt pool as assessed by isotope dilution was similar in all groups.

CONCLUSIONS

Thus, lithogenic bile develops in this model because of reduced bile salt secretion and increased cholesterol secretion. Cisapride renders biliary lipid composition towards normal by enhancing gallbladder (and possibly intestinal) motility and cycling of the bile salt pool, thereby increasing bile salt secretion.