[Comparison between laparoscopic-assisted natural orifice specimen extraction surgery and conventional laparoscopic surgery for left colorectal cancer: 5-year follow-up results of a randomized controlled study]

Objective: To evaluate the long-term efficacy of laparoscopic-assisted natural orifice specimen extraction surgery (NOSES) colectomy using Cai tube for treating left-sided colorectal cancer. Methods: This was a randomized controlled trial. Inclusion criteria were as follows: preoperative pathological diagnosis of left-sided colorectal adenocarcinoma (rectal, sigmoid colon, descending colon, or left transverse colon cancer with the caudad margin ≥8 cm from the anal margin); preoperative abdominal and pelvic computed tomography (or magnetic resonance imaging) showing maximum tumor diameter <4.5 cm; and BMI <30 kg/m2. Patients with synchronous multiple primary cancers or recurrent cancers, a history of neoadjuvant chemoradiotherapy, preoperative evidence of significant local infiltration, distant metastasis, or complications such as intestinal obstruction and intestinal perforation, or who were not otherwise considered suitable for laparoscopic surgery were excluded. A random number table was used to randomize sequential patients to NOSES surgery using Cai tube (non-assisted incision anal sleeve: patent number ZL201410168748.2) (NOSES group) or traditional laparoscopic-assisted surgery (CLS group). Relevant clinical data of the two groups of patients were analyzed, the main outcomes being disease-free survival, overall survival, overall recurrence rate, and local recurrence rate 5 years after surgery. Results: Patients in both study groups completed the surgery successfully with no requirement for additional surgery. After mean 70 (7-83) months postoperative follow-up, the 5-year overall postoperative survival in the NOSES and CLS groups was 90.0% and 83.3%, respectively (P=0.455); disease free survival was 90.0% and 83.3%, respectively (P=0.455); overall recurrence rate 6.6% and 10.0%, respectively (P=0.625); and local recurrence rate both were 3.3% (P=0.990), respectively. None of these differences was statistically significant. Conclusions: NOSES and CLS have similar long-term efficacy, and NOSES deserves to be used in clinical practice.

[Specimen extraction through natural orifices with Cai tubes in gastrointestinal surgery: a single-institute series of 234 cases]

Objective: To investigate the feasibility of Cai tube-assisted natural orifice specimen extraction surgery (NOSES) in gastrointestinal surgery. Methods: This was a descriptive case-series study. Inclusion criteria: (1) colorectal or gastric cancer diagnosed by preoperative pathological examination or redundant sigmoid or transverse colon detected by barium enema; (2) indications for laparoscopic surgery; (3) body mass index <30 kg/m² (transanal surgery) and 35 kg/m² (transvaginal surgery); (4) no vaginal stenosis or adhesions in female patients undergoing transvaginal specimen extraction; and (5) patients with redundant colon aged 18-70 years and a history of intractable constipation for more than 10 years. Exclusion criteria: (1) colorectal cancer with intestinal perforation or obstruction, or gastric cancer with gastric perforation, gastric hemorrhage, or pyloric obstruction; (2) simultaneous resection of lung, bone, or liver metastases ; (3) history of major abdominal surgery or intestinal adhesions; and (4) incomplete clinical data. From January 2014 to October 2022, 209 patients with gastrointestinal tumors and 25 with redundant colons who met the above criteria were treated by NOSES utilizing a Cai tube (China invention patent number:ZL201410168748.2) in the Department of Gastrointestinal Surgery, Zhongshan Hospital, Xiamen University. The procedures included eversion and pull-out NOSES radical resection in 14 patients with middle and low rectal cancer, NOSES radical left hemicolectomy in 171 patients with left-sided colorectal cancer, NOSES radical right hemicolectomy in 12 patients with right-sided colon cancer, NOSES systematic mesogastric resection in 12 patients with gastric cancer, and NOSES subtotal colectomy in 25 patients with redundant colons. All specimens were collected by using an in-house-made anal cannula (Cai tube) with no auxiliary incisions. The primary outcomes included 1-year recurrence-free survival (RFS) and postoperative complications. Results: Among 234 patients, 116 were male and 118 were female. The mean age was (56.6±10.9) years. NOSES was successfully completed in all patients without conversion to open surgery or procedure-related death. The negative rate of circumferential resection margin was 98.8% (169/171) with both two positive cases having left-sided colorectal cancer. Postoperative complications occurred in 37 patients (15.8%), including 11 cases (4.7%) of anastomotic leakage, 3 cases(1.3%) of anastomotic bleeding, 2 cases (0.9%) of intraperitoneal bleeding, 4 cases (1.7%) of abdominal infection, and 8 cases (3.4%) of pulmonary infection. Reoperations were required in 7 patients (3.0%), all of whom consented to creation of an ileostomy after anastomotic leakage. The total readmission rate within 30 days after surgery was 0.9% (2/234). After a follow-up of (18.3±3.6) months, the 1-year RFS was 94.7%. Five of 209 patients (2.4%) with gastrointestinal tumors had local recurrence, all of which was anastomotic recurrence. Sixteen patients (7.7%) developed distant metastases, including liver metastases(n=8), lung metastases(n=6), and bone metastases (n=2). Conclusion: NOSES assisted by Cai tube is feasible and safe in radical resection of gastrointestinal tumors and subtotal colectomy for redundant colon.

[Comparison between laparoscopic-assisted natural orifice specimen extraction surgery and conventional laparoscopic surgery for left colorectal cancer: a randomized controlled study with 3-year follow-up results]

Objective: To evaluate the mid-term efficacy of laparoscopic-assisted natural orifice specimen extraction surgery (NOSES) colectomy using the Cai tube in the treatment of left colorectal cancer. Methods: A prospective randomized control trial (China Clinical Trials Registration Number: ChiCTR-OOR-15007060) was performed. Sixty patients with left colorectal cancer at Department of Gastrointestinal Surgery of Zhongshan Hospital from September 2015 to August 2017 were prospectively enrolled. Case inclusion criteria: (1) left colorectal adenocarcinoma (rectal cancer with distance ≥ 8 cm from tumor low margin to anal edge, sigmoid colon cancer, descending colon cancer and left transverse colon cancer) confirmed by preoperative pathology; (2) satisfactory conditions of conventional laparoscopic surgery; (3) maximum diameter of the tumor < 4.5 cm confirmed by preoperative abdominal and pelvic CT or MRI; (4) BMI < 30 kg/m². Case exclusion criteria: (1) benign lesions, mucinous adenocarcinoma, signet-ring cell carcinoma and other special pathological types of tumors confirmed by preoperative pathological examination; (2) multiple or recurrent cancers; (3) with a history of neoadjuvant chemoradiotherapy; (4) obvious regional infiltration or distant metastasis indicated by preoperative imaging examination; (5) intestinal obstruction, intestinal perforation, etc. Participants were randomly assigned to NOSES group (using the Cai tube) and conventional laparoscopy (CL) group by random number table method. Clinical data between two groups were compared and analyzed, including perioperative conditions, tumor exfoliation cell detection and bacterial culture results of intraperitoneal lavage fluid, postoperative complications (Clavien-Dindo grading), postoperative pain [visual simulation scoring (VAS) assessment], anal function (Kirwan anal function grading assessment), and postoperative 3-year disease-free survival (DFS), overall survival (OS), overall recurrence rate, and local recurrence rate. Results: A total of 60 patients were enrolled, with 30 in the NOSES group and 30 in the CL group. All the patients in the NOSES group successfully completed operation with Cai tube. Baseline data between the two groups were not significantly different (all P>0.05). There were no statistically significant differences between two groups in conversion rate to open surgery, number of lymph node harivested, proximal and distal resection margin of tumor, negative rate of circumferential margin, operation time, blood loss, inflammatory indexes, postoperative anal function, postoperative hospital stay, hospitalization cost, morbidity of postoperative complications (Clavien-Dindo grade II or above) (all P>0.05). Compared to the CL group, the NOSES group had lower maximum postoperative VAS score (2.5±0.3 vs. 5.1±0.4, t=3.187, P<0.01), and fewer use of additional postoperative analgesia [6.7% (2/30) vs. 33.3% (10/30),χ²=6.670, P=0.02]. The postoperative time to gas passage was shorter in the NOSES group [(2.2±1.4) days vs. (3.1±1.2) days,P=0.026]. No tumor cells and bacterial contamination were found in abdominal lavage fluid before and after operation in either group. The anal function at postoperative 3-month of all the patients in the NOSES group was Kirwan grade I to II, while in the CL group, anal function of 2 cases (6.7%) was Kirwan grade III, and of 28 cases was also Kirwan grade I to II, whose difference was not statistically significant (P>0.05). In the NOSES group and the CL group, 3-year DFS was 96.7% and 83.3% (P=0.090), OS was 100% and 90% (P=0.096), overall recurrence rate was 3.3% and 10.0% (P=0.166), and local recurrence rate was 3.3% and 3.3% (P=0.999), respectively, whose differences were not statistically significant (all P>0.05). Conclusions: In the treatment of left colorectal cancer, compared with conventional laparoscopic colectomy, NOSES colectomy using Cai tube exhibits less scar, less postoperative pain, shorter recovery of gastrointestinal function, and similar mid-term outcomes. Given proper surgical indications, the surgical procedure is safe and feasible.

[Antibiotic resistance and virulence characteristics analysis of a carbapenem-resistant hypervirulent Klebsiella pneumoniae]

Objective: To characterize the antibiotic resistance and virulence in a carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods: A CRKP (designated K. pneumoniae C35) was isolated from a stool sample. The minimal inhibitory concentrations of antimicrobial agents were determined using the broth microdilution method. Whole-genome sequencing and genome analysis were performed to identify the antibiotic resistance and virulence genes. The genetic relationship among K. pneumoniae C35 and other CRKP isolates from our hospital was analyzed by single nucleotide polymorphism (SNP) typing of core genomes. Conjugation experiments were carried out by filter mating to evaluate the transferability and efficiency of resistance genes. The virulence phenotype was determined by Galleria mellonella infection model. Results: K. pneumoniae C35 exhibited resistance to the majority of tested antibiotics, especially carbapenems, sulbactam, and polymyxins. SNP typing showed that K. pneumoniae C35 shared a high degree of sequence homology with several CRKP isolates from different wards. This ST11 CRKP carried 13 resistance genes, including bla_KPC-2, bla_CTX-M-199, mcr-1, and tet(A) variant. bla_KPC-2 gene was located on an IncFⅡ plasmid with>69 800 bp in size, bla_CTX-M-199 and mcr-1 genes were located on an IncI2 plasmid (>64 800 bp), and tet(A) variant was located on an unknown Inc-type plasmid (83 628bp). All these three plasmids were conjugative. K. pneumoniae C35 was found to harbor rmpA, rmpA2, and iucABCD aerobactin-related genes, and was considered to be classic carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP). The virulence potential of this strain was confirmed in a Galleria mellonella infection model. The survival rate of the larvae injected with strain C35 at 48 h after infection was significantly lower than that of negative control strain (16.7% vs 80.0%). Conclusion: Multiple conjugative plasmids are identified in a faecal CR-hvKP. The IncI2 plasmid co-carrying both bla_CTX-M-199 and mcr-1 genes is firstly identified in CR-hvKP. The emergence of such strain should be alerted and active surveillance is warranted.

Synthesis and biological activities of dibenzyl dipiperazine diquaternary ammonium salts

Twenty new 4,4'-dibenzoyl-1,1'-dibenzyl-1,1'-(decane-1,5-diyl)-piperazi nium dihalides 5a-l and 1,1'-dibenzyl-1,1'-(decane-1,5-diyl)piperazinium dihydrochloride dihalides 6a-l were prepared and evaluated for their analgesic, sedative and anti-inflammatory activities. Structure-activity relationship studies indicated that the compounds 6c (Ar = 4-NO2C6H5) and 6k (Ar = 3-Me-C6H5) exhibited higher activities than others. Compared with the corresponding compounds 6k and 6l, the presence of benzoyl in the compound 5k and 5l exerted a contrary influence on the activities. 5h and 6h show the highest anti-inflammatory activity (59%, dose 20 mg/kg and 48%, dose 1 mg/kg) in the series 5 and 6, respectively.

Spontaneous intestinal carcinomas and skin neoplasms in Msh2-deficient mice

Hereditary nonpolyposis colorectal cancer is associated with defects in DNA mismatch repair. Here, we characterize tumor susceptibility of the recently described Msh2-deficient mouse model. Within the first year of observation, all homozygous mice succumbed to disease, with lymphomas observed in at least 80% of the cases. The majority (70%) of animals 6 months or older developed intestinal neoplasms associated with APC inactivation. Microsatellite instability was more common in carcinomas than in adenomas, but uncommon in normal tissues. Some animals (7%) developed a variety of skin neoplasms analogous to the Muir-Torre syndrome. Msh2-/- mice implicate a direct role for mismatch repair in several neoplasms with striking phenotypic similarities to humans.

MSH2 deficiency contributes to accelerated APC-mediated intestinal tumorigenesis

Accelerated intestinal tumorigenesis is probable in hereditary nonpolyposis colorectal cancer, a condition associated with germ line DNA mismatch repair (MMR) gene defects, and is believed to be caused by rapid accumulation of replication errors in critical genes, such as the APC (adenomatous polyposis coli) tumor suppressor gene. To study the potential contribution of MMR genes to accelerated intestinal tumorigenesis, we crossed the Min mouse, heterozygous for a germ line mutation of Apc, with an MMR gene (Msh2)-deficient mouse. MSH2 deficiency resulted in the development of many colonic aberrant crypt foci, as well as reduced survival of the mice, secondary to both a greater number and more rapidly developing adenomas. The mechanism of inactivation of the wild-type Apc allele depended on MSH2 status. In the presence of functional MSH2, all tumors demonstrated loss of heterozygosity. In contrast, whereas all adenomas were APC negative by immunostaining, only 5 of 34 adenomas from Apc+/-/Msh2-/- mice demonstrated loss of heterozygosity of the wild-type Apc allele, suggesting that somatic Apc mutations are responsible for the additional tumors. These findings provide evidence for the important role of MMR genes in accelerated intestinal tumorigenesis, thus supporting more aggressive surveillance strategies to prevent colorectal cancer in hereditary nonpolyposis colorectal cancer.

[Synergism of sobuzoxane in combination with doxorubicin against leukemia P388 in mice]

AIM

To study the antitumor activity of sobuzoxane (Sob) in combination with doxorubicin (Dox) and the effect of Sob on Dox-induced cardiotoxicity.

METHODS

DBA/2 mice bearing transplanted leukemia P388 were given i.v. Dox 2 mg.kg-1.d-1 for 3 d, 4 mg.kg-1.d-1 for 1 d combined with ig Sob 20, 40 mg.kg-1.d-1 for 7 d. The increase in life span (ILS) of each group was recorded in 30 d. The myocardium of moribund mice was examined by transmission electron microscopy.

RESULTS

The ILS of combination therapeutic groups of Sob with Dox was 48.7%, 57.3%, 59.0%, and 62.4% respectively, which were 30%-90% higher than the sum of ILS of two groups treated with Dox and Sob separately (P < 0.01). The ultrastructural injury of cardiomyocytes of P388-bearing mice caused by combination chemotherapy with Dox plus Sob was markedly attenuated compared with Dox alone.

CONCLUSION

Sob with Dox exhibited an antitumor synergistic effect on leukemia P388, and the cardiotoxicity of Dox was reduced by Sob.

Synthesis and antitumor properties of N1-acyloxymethyl derivatives of bis(2,6-dioxopiperazines)

Many N1-acyloxymethyl derivatives VI of bis(2,6-dioxopiperazine) I, ICRF-154, were prepared and tested for antitumor activity. The treatment of I with formaldehyde gave a crystalline bis(N1-hydroxymethyl) derivative VII, which was acylated under various conditions to give bis(N1-acyloxymethyl) derivatives VI. Antitumor activity of VI against P388 leukemia in mice was studied. Several bis(N1-acyloxymethyl) compounds such as phenylacetyloxymethyl VI-6, methoxycarbonyloxymethyl VI-41, isobutoxycarbonyloxymethyl VI-44, and furancarboxymethyl VI-38 compounds were found to have potent antitumor activities. On the other hand, water-soluble esters having an amine or a carboxylic acid function in their acyl groups showed rather reduced activity. These bis(N1-acyloxymethyl) derivatives VI were presumably hydrolyzed into the parent bis(2,6-dioxopiperazine) I by nonspecific esterase in the body to exhibit their antitumor activity.