Previous transanal full-thickness excision increases the morbidity of radical resection for rectal cancer

AIM

The aim of the study was to determine the impact of primary full-thickness transanal excision (TAE) on the morbidity rate following radical rectal resection for cancer.

METHOD

Fourteen consecutive patients underwent radical resection for lower third rectal cancer following full-thickness TAE without closure of the defect. They were compared with 25 matched patients from a prospective database of 275 rectal resections who had undergone radical resection without previous TAE for lower third rectal cancer (control group). The confounding factors were: age, sex, body mass index (BMI), classification according to the American Society of Anaesthesiologists, administration of neoadjuvant radiotherapy before rectal resection, tumour stage and type of surgical procedure.

RESULTS

There were no deaths. Overall morbidity was 64.3% in the TAE group and 32% in the control group (P = 0.112). Surgical complications were significantly more frequent in the former (57.1%vs 20%; P = 0.048). The frequency of specific surgical site complications, including anastomotic complications and pelvic abscess formation requiring surgical drainage, was significantly higher in the TAE group than in the control group (42.8%vs 8%; P = 0.032). In univariate analysis, the only factors associated with specific surgical site complications were BMI > 27 and TAE before rectal resection.

CONCLUSION

This case-matched study suggests that previous full-thickness TAE increases the risk of surgical complications after radical resection for lower third rectal cancer, including anastomotic dehiscence and pelvic sepsis.

Salvage colectomy for endoscopically removed malignant colon polyps: is it possible to determine the optimal number of lymph nodes that need to be harvested?

AIM

The total number of lymph nodes examined after salvage colectomy for endoscopically removed malignant polyps was evaluated and an attempt was made to determine whether there was an optimal number of lymph nodes that should be harvested.

METHOD

From 2000 to 2009, 531 patients underwent segmental resection for non-metastatic colon cancer. Of these, 22 underwent a salvage colectomy for an endoscopically removed malignant polyp, the main indication for which was a resection margin of < 1 mm. The surgical procedure was identical to that used for all colon cancers.

RESULTS

The mean number of lymph nodes examined was 11.6 ± 7.6 for the 22 patients with an endoscopically removed malignant polyp and 26.2 ± 13.9 for the remaining 509 patients (P = 0.0006). Fewer than 12 lymph nodes were examined in 62 (12%) of the 509 patients and in 13 (59%) of the 22 patients with an endoscopically removed malignant polyp (P < 0.0001). In the group of 22 patients who underwent a salvage colectomy, the total number of lymph nodes examined ranged from 2 to 33. At a mean follow up of 41 ± 15.6 months, no local or distant recurrence was observed in the 22 patients.

CONCLUSION

The total number of lymph nodes examined after colectomy for endoscopically removed malignant polyps varies and is less than the recommended number of 12 in most cases: this does not appear to have long-term prognostic significance. There is no biological reason to explain this clinical observation.

Where does pelvic nerve injury occur during rectal surgery for cancer?

AIM

Optimal treatment of rectal adenocarcinoma involves total mesorectal excision with nerve-preserving dissection. Urinary and sexual dysfunction is still frequent following these procedures. Improved knowledge of pelvic nerve anatomy may help reduce this and define the key anatomical zones at risk.

METHOD

The MEDLINE database was searched for available literature on pelvic nerve anatomy and damage after rectal surgery using the key words 'autonomic nerve', 'pelvic nerve', 'colorectal surgery', and 'genitourinary dysfunction'. All relevant French and English publications up to May 2010 were reviewed. Reviewed data were illustrated using 3D reconstruction of the foetal pelvis.

RESULTS

The ligation of the inferior mesenteric artery and dissection of the retrorectal space can cause damage to the superior hypogastric plexus and/or hypogastric nerve. Anterolateral dissection in the 'lateral ligament' area and division of Denonvilliers' fascia can damage the inferior hypogastric plexus and efferent pathways. Perineal dissection can indirectly damage the pudendal nerve.

CONCLUSIONS

In most cases, the pelvic nerves can be preserved during rectal surgery. Complete oncological resection may require dissection close to the nerves where the tumour is located anterolaterally where it is fixed and when the pelvis is narrow.

Post-ischaemic activation of kinases in the pre-conditioning-like cardioprotective effect of the platelet-activating factor

AIM

Platelet-activating factor (PAF) triggers cardiac pre-conditioning against ischemia/reperfusion injury. The actual protection of ischaemic pre-conditioning occurs in the reperfusion phase. Therefore, we studied in this phase the kinases involved in PAF-induced pre-conditioning.

METHODS

Langendorff-perfused rat hearts underwent 30 min of ischaemia and 2 h of reperfusion (group 1, control). Before ischaemia, group 2 hearts were perfused for 19 min with PAF (2 x 10(-11) M); groups 3-5 hearts were co-infused during the initial 20 min of reperfusion, with the protein kinase C (PKC) inhibitor chelerythrine (5 x 10(-6) M) or the phosphoinositide 3-kinase (PI3K) inhibitor LY294002 (5 x 10(-5) M) and atractyloside (2 x 10(-5) M), a mitochondrial permeability transition pore (mPTP) opener respectively. Phosphorylation of PKCepsilon, PKB/Akappat, GSK-3beta and ERK1/2 at the beginning of reperfusion was also checked. Left ventricular pressure and infarct size were determined.

RESULTS

PAF pre-treatment reduced infarct size (33 +/- 4% vs. 64 +/- 5% of the area at risk of control hearts) and improved pressure recovery. PAF pre-treatment enhanced the phosphorylation/activation of PKCepsilon, PKB/Akappat and the phosphorylation/inactivation of GSK-3beta at reperfusion. Effects on ERK1/2 phosphorylation were not consistent. Infarct-sparing effect and post-ischaemic functional improvement induced by PAF pre-treatment were abolished by post-ischaemic infusion of either chelerythrine, LY294002 or atractyloside.

CONCLUSIONS

The cardioprotective effect exerted by PAF pre-treatment involves activation of PKC and PI3K in post-ischaemic phases and might be mediated by the prevention of mPTP opening in reperfusion via GSK-3beta inactivation.

[Functional outcome after hand-sewn versus stapled colonic J pouch anastomosis for rectal carcinoma]

STUDY AIM

The aim of this study was to compare the surgical and functional results of hand-sewn and stapled colonic J-pouch anastomoses after proctectomies for cancer.

PATIENTS AND METHODS

Over a 6-year period, 120 patients had a laparotomic conservative rectal excision with total mesorectal excision but without intersphincteric dissection, for cancer of the mid- and lower rectum: the colonic J-pouch anastomosis was hand-sewn for 49 and stapled for 71 patients. The functional results were assessed at 1 year, by a questionnaire completed by the patient.

RESULTS

Morbidity was 37% in the hand-sewn group and 38% in the stapled group (ns). Mean duration of surgery in the hand-sewn group was 288 minutes and in the stapled group, 246 minutes (p<0.001). At 1 year, the rate of perfect continence was 71% for the hand-sewn group and 76% for the stapled group (ns). Significantly, more patient from the hand-sewn groups used enemas (16% versus 3%, p<0.005). On the other hand, there was no significant difference between the two groups for wearing protection, urgency, number of stools a day or gas/stool discrimination.

CONCLUSIONS

There is no major difference in either the surgical or functional results between hand-sewn or stapled colonic J-pouch anastomosis by laparotomy for rectal cancer. Because it is simpler and faster to perform, a stapled pouch is preferable when the tumor site so permits.

Mesenchymal stem cell interaction with a non-woven hyaluronan-based scaffold suitable for tissue repair

The fabrication of biodegradable 3-D scaffolds enriched with multipotent stem cells seems to be a promising strategy for the repair of irreversibly injured tissues. The fine mechanisms of the interaction of rat mesenchymal stem cells (rMSCs) with a hyaluronan-based scaffold, i.e. HYAFF(R)11, were investigated to evaluate the potential clinical application of this kind of engineered construct. rMSCs were seeded (2 x 10(6) cells cm(-2)) on the scaffold, cultured up to 21 days and analysed using appropriate techniques. Light (LM), scanning (SEM) and transmission (TEM) electron microscopy of untreated scaffold samples showed that scaffolds have a highly porous structure and are composed of 15-microm-thick microfibres having a rough surface. As detected by trypan blue stain, cell adhesion was high at day 1. rMSCs were viable up to 14 days as shown by CFDA assay and proliferated steadily on the scaffold as revealed by MTT assay. LM showed rMSCs in the innermost portions of the scaffold at day 3. SEM revealed a subconfluent cell monolayer covering 40 +/- 10% of the scaffold surface at day 21. TEM of early culture showed rMSCs wrapping individual fibres with regularly spaced focal contacts, whereas confocal microscopy showed polarized expression of CD44 hyaluronan receptor; TEM of 14-day cultures evidenced fibronexus formation. Immunohistochemistry of 21-day cultures showed that fibronectin was the main matrix protein secreted in the extracellular space; decorin and versican were seen in the cell cytoplasm only and type IV collagen was minimally expressed. The expression of CD90, a marker of mesenchymal stemness, was found unaffected at the end of cell culture. Our results show that HYAFF(R)11 scaffolds support the adhesion, migration and proliferation of rMSCs, as well as the synthesis and delivery of extracellular matrix components under static culture conditions without any chemical induction. The high retention rate and viability of the seeded cells as well as their fine modality of interaction with the substrate suggest that such scaffolds could be potentially useful when wide tissue defects are to be repaired as in the case of cartilage repair, wound healing and large vessel replacement.

Comparison of the number of uterine myomas detected by in-office transvaginal ultrasonography removed by laparotomic myomectomy: preoperative work-up concerns

PURPOSE OF INVESTIGATION

To assess the ability of detecting the number of uterine myomas by transvaginal ultrasonography (TVS) performed supporting the clinical examination of general gynecologists' office practice.

METHODS

A retrospective comparison of the number of myomas revealed by preoperative in-office TVS and documented after laparotomic myomectomy was conducted in 110 consecutive premenopausal patients referred for surgery.

RESULTS

The sensitivity of TVS in revealing the exact number of myomas was 59.4% in the whole series. In the subgroup of 88 patients with a preoperative diagnosis of three or fewer myomas TVS missed at least one myoma in 31 (35.2%) cases, achieving a 64.8% sensitivity. Among the 72 women diagnosed with one myoma at preoperative TVS, 19 (26.4%) resulted to have two or more myomas at the end of surgery, reaching a 73.6% sensitivity of TVS in revealing the exact number of myomas.

CONCLUSIONS

In-office TVS reinforces the clinical diagnosis of uterine myomas but it often fails in the detection of their number, resulting in a poor preoperative characterization of patients. The fact that one myoma may be overlooked in one-third of patients theoretically eligible for laparoscopic conservative surgery may motivate the implementation of US diagnosis when laparoscopic myomectomy is considered.

Presentation and prognosis of local recurrence after total mesorectal excision

OBJECTIVE

The aim of this study was to describe the presentation, treatment and prognosis of local recurrences following total mesorectal excision for rectal adenocarcinoma.

METHOD

Between 1999 and 2002, 201 patients were treated with total mesorectal excision for mid or low rectal cancer and were followed up prospectively.

RESULTS

Overall 2-year survival was 85%. The 2-year recurrence rate was 8%. Eighteen patients developed local recurrence at 3-60 months. Nine recurrences originated from the pelvic sidewall. These recurrences were symptomatic in 90% of patients. Only two patients were reoperated with a R0 resection and were alive without local recurrence after 19 and 31 months. The seven others died within 9 months. Nine recurrences originated from an anastomotic suture line. Only two had symptoms. A R0 surgical resection was performed in all patients with a 67% sphincter conservation rate. After 26-months of median follow-up (range 7-58), all patients were alive.

CONCLUSION

Half of the local recurrence after total mesorectal excision was located at the anastomotic site. Rectoscopic examination should be performed regularly to detect these anatomotic recurrences that are accessible to a R0 itérative resection.

Synergistic effects against post-ischemic cardiac dysfunction by sub-chronic nandrolone pretreatment and postconditioning: role of beta2-adrenoceptor

Beta(2)-adrenoreceptor overexpression is beneficial against ischemia/reperfusion (I/R) injury. Whether beta-adrenoreceptors are involved in postconditioning (PostC) is unknown. We investigated whether nandrolone-decanoate (ND)-pretreatment can modulate (1) beta-adrenoreceptor expression and (2) post-ischemic cardiac function in response to I/R and PostC. Finally, we tested whether cardioprotection can be prevented by the inhibition of beta(2)-adrenoreceptors. Isolated rat hearts from ND pretreated (15 mg/kg/day i.m., for 14 days) and untreated-animals underwent 30-min ischemia and 120-min reperfusion. In subgroups, at the end of ischemia a PostC protocol (five cycles of 10-s reperfusion and 10-s ischemia) was applied and/or a beta(2)-adrenoreceptor blocker, ICI-118.551 (10 microM), was infused. Left ventricular pressure (LVP) was measured with an electromanometer, and infarct-size was evaluated using nitro-blue-tetrazolium staining. ND-pretreatment increased beta(2)-adrenoreceptor expression, but did not alter cardiac-weight, LVP and maximum rate of increase of LVP (dP/dt(max)). After I/R, infarct-size was smaller in ND-pretreatment than in untreated-animals. Infarct-size was also reduced by PostC, both in untreated and ND-pretreated animals. Contracture was less marked in ND-pretreated animals. PostC reduced contracture in both ND-pretreated and untreated hearts. Moreover, PostC improved post-ischemic recovery of developed LVP and dP/dt(max) much more in earts of ND-pretreated than untreated-animals. ICI-118.551 abolished ND protection and PostC-protection both in ND-pretreated and untreated hearts. Data show that two-weeks ND-pretreatment induces 1) an overexpression of beta(2)-ARs without cardiac hypertrophy and 2) improves the post-ischemic diastolic and systolic cardiac function. Intriguingly, ND-pretreatment potentiates the improvement of systolic function induced by postconditioning via beta(2)-adrenoreceptor activation.

The platelet activating factor triggers preconditioning-like cardioprotective effect via mitochondrial K-ATP channels and redox-sensible signaling

Endogenous platelet activating factor (PAF) is involved in heart ischemic preconditioning. PAF can also afford pharmacological preconditioning. We studied whether mitochondrial-ATP-sensitive K(+) (mK(ATP)) channels and reactive oxygen species (ROS) are involved in PAF-induced cardioprotection. In Group 1 control hearts, Langendorff-perfused rat hearts underwent 30 min ischemia and 2 hours of reperfusion. Group 2 hearts, before ischemia, were perfused for 19 min with PAF (2x10(-11) M); Groups 3 and 4 hearts were co-infused with PAF and N-acetyl-L-cysteine or 5-hydroxydecanoate to scavenge ROS or to block mK(ATP) channels, respectively. Left ventricular pressure and infarct size were determined. PAF-pretreatment reduced infarct size (33 +/- 4% vs 64 +/- 4.6 % of the area at risk of control hearts) and improved pressure recovery. Infarct-sparing effect of PAF was abolished by N-acetyl-L-cysteine and 5-hydroxydecanoate. Thus, the cardioprotective effect exerted by PAF-pretreatment involves activation of mK(ATP) channels and redox signaling in pre-ischemic phase.

Prognostic significance of high-risk HPV persistence after laser CO2 conization for high-grade CIN: a prospective clinical study

PURPOSE OF INVESTIGATION

To estimate the persistence rate of high-risk HPV DNA (HR-HPV DNA) in a population treated totally by laser CO2 conization for high-grade cervical intraepithelial neoplasia (HG-CIN), and to examine if this persistence might be considered an independent risk factor for relapsing disease.

METHODS

All women with a histological diagnosis of HG-CIN and planned for laser CO2 conization from January 2003 to December 2004 were prospectively submitted to a HR-HPV test prior to surgery and at three and six months of follow-up. Women providing written informed consent with 24 months of follow-up were enrolled in the study group. A positive HPV test, involvement of resection margins, age at first intercourse, smoking habits, parity and age at conization > 50 years old were considered as risk factors for relapsing HG-CIN during follow-up, and were univariately and multivariately analyzed to discover any independent influencing factors.

RESULTS

Of HG-CIN 15.4% resulted not to be HPV related nor relapsing. The HPV clearance rate after treatment was 78.8%. Involvement of resection margins and HR-HPV DNA persistence post-treatment resulted as the only two statistically significant risk factors for HG-CIN recurrence (rate 3.8%). HR-HPV DNA persistence in follow-up resulted to be independent from other risk factors at multivariate analysis.

CONCLUSIONS

Although able to reach a low recurrence rate of HG-CIN, laser CO2 conization does not remove HPV infection completely from the cervix with a case of persistence in every five treated patients. In our experience this persistence in itself represents an independent risk factor for developing relapsing disease and constitutes the basis to introduce HPV testing even in the follow-up of patients treated for HG-CIN by laser CO2 conization.

The paradigm of postconditioning to protect the heart

Ischaemic preconditioning limits the damage induced by subsequent ischaemia/reperfusion (I/R). However, preconditioning is of little practical use as the onset of an infarction is usually unpredictable. Recently, it has been shown that the heart can be protected against the extension of I/R injury if brief (10–30 sec.) coronary occlusions are performed just at the beginning of the reperfusion. This procedure has been called postconditioning (PostC). It can also be elicited at a distant organ, termed remote PostC, by intermittent pacing (dyssynchrony-induced PostC) and by pharmacological interventions, that is pharmacological PostC. In particular, brief applications of intermittent bradykinin or diazoxide at the beginning of reperfusion reproduce PostC protection. PostC reduces the reperfusion-induced injury, blunts oxidant-mediated damages and attenuates the local inflammatory response to reperfusion. PostC induces a reduction of infarct size, apoptosis, endothelial dysfunction and activation, neutrophil adherence and arrhythmias. Whether it reduces stunning is not clear yet. Similar to preconditioning, PostC triggers signalling pathways and activates effectors implicated in other cardioprotective manoeuvres. Adenosine and bradykinin are involved in PostC triggering. PostC triggers survival kinases (RISK), including A t and extracellular signal-regulated kinase (ERK). Nitric oxide, via nitric oxide synthase and non-enzymatic production, cyclic guanosine monophosphate (cGMP) and protein kinases G (PKG) participate in PostC. PostC-induced protection also involves an early redox-sensitive mechanism, and mitochondrial adenosine-5′ -triphosphate (ATP)-sensitive K⁺ and PKC activation. Protective pathways activated by PostC appear to converge on mitochondrial permeability transition pores, which are inhibited by acidosis and glycogen synthase kinase-3β (GSK-3β). In conclusion, the first minutes of reperfusion represent a window of opportunity for triggering the aforementioned mediators which will in concert lead to protection against reperfusion injury. Pharmacological PostC and possibly remote PostC may have a promising future in clinical scenario.

Nitric oxide and cardiac function

Nitric oxide (NO) participates in the control of contractility and heart rate, limits cardiac remodeling after an infarction and contributes to the protective effect of ischemic pre- and postconditioning. Low concentrations of NO, with production of small amounts of cGMP, inhibit phosphodiesterase III, thus preventing the hydrolysis of cAMP. The subsequent activation of a protein-kinase A causes the opening of sarcolemmal voltage-operated and sarcoplasmic ryanodin receptor Ca(2+) channels, thus increasing myocardial contractility. High concentrations of NO induce the production of larger amounts of cGMP which are responsible for a cardiodepression in response to an activation of protein kinase G (PKG) with blockade of sarcolemmal Ca(2+) channels. NO is also involved in reduced contractile response to adrenergic stimulation in heart failure. A reduction of heart rate is an evident effect of NO-synthase (NOS) inhibition. It is noteworthy that the direct effect of NOS inhibition can be altered if baroreceptors are stimulated by increases in blood pressure. Finally, NO can limit the deleterious effects of cardiac remodeling after myocardial infarction possibly via the cGMP pathway. The protective effect of NO is mainly mediated by the guanylyl cyclase-cGMP pathway resulting in activation of PKG with opening of mitochondrial ATP-sensitive potassium channels and inhibition of the mitochondrial permeability transition pores. NO acting on heart is produced by vascular and endocardial endothelial NOS, as well as neuronal and inducible synthases. In particular, while in the basal control of contractility, endothelial synthase has a predominant role, the inducible isoform is mainly responsible for the cardiodepression in septic shock.

[Colorectal carcinogenesis. 1. Hereditary predisposition and colorectal cancer]

Tumors arising sporadically represent 70-80% of colorectal cancer (CRC). The two best defined forms of inherited CRC-familial multiple polyposis (FMP) and Hereditary Non-Polyposis Colon Cancer (HNPCC) account respectively for<1% and 2-3% of CRC. These rare genetic syndromes (FMP, HNPCC, Peutz-Jeghers Syndrome) are caused by major predisposing gene mutations (APC gene, MMR gene, BMPR1A. SMAD4,...) and local environmental factors play only a minor role. In the sporadic forms of CRC, 25% have significant genetic predisposition probably related to alleles with weak penetration (APC*I1307K, TGFbR1*6Ala...) and are more strongly affected by environmental factors.

Plant-growth-promoting compounds produced by two agronomically important strains of Azospirillum brasilense, and implications for inoculant formulation

We evaluated phytohormone and polyamine biosynthesis, siderophore production, and phosphate solubilization in two strains (Cd and Az39) of Azospirillum brasilense used for inoculant formulation in Argentina during the last 20 years. Siderophore production and phosphate solubilization were evaluated in a chemically defined medium, with negative results. Indole 3-acetic acid (IAA), gibberellic acid (GA(3)), and abscisic acid (ABA) production were analyzed by gas chromatography-mass spectrometry. Ethylene, polyamine, and zeatin (Z) biosynthesis were determined by gas chromatography-flame ionization detector and high performance liquid chromatography (HPLC-fluorescence and -UV), respectively. Phytohormones IAA, Z, GA(3), ABA, ethylene, and growth regulators putrescine, spermine, spermidine, and cadaverine (CAD) were found in culture supernatant of both strains. IAA, Z, and GA(3) were found in all two strains; however, their levels were significantly higher (p < 0.01) in Cd (10.8, 2.32, 0.66 microg ml(-1)). ABA biosynthesis was significantly higher (p < 0.01) in Az39 (0.077 microg ml(-1)). Ethylene and polyamine CAD were found in all two strains, with highest production in Cd cultured in NFb plus L-methionine (3.94 ng ml(-1) h(-1)) and Az39 cultured in NFb plus L-lysine (36.55 ng ml(-1) h(-1)). This is the first report on the evaluation of important bioactive molecules in strains of A. brasilense as potentially capable of direct plant growth promotion or agronomic yield increase. Az39 and Cd showed differential capability to produce the five major phytohormones and CAD in chemically defined medium. This fact has important technological implications for inoculant formulation as different concentrations of growth regulators are produced by different strains or culture conditions.

Phytohormone production by three strains of Bradyrhizobium japonicum and possible physiological and technological implications

The aim of this work was to evaluate phytohormone biosynthesis, siderophores production, and phosphate solubilization in three strains (E109, USDA110, and SEMIA5080) of Bradyrhizobium japonicum, most commonly used for inoculation of soybean and nonlegumes in USA, Canada, and South America. Siderophore production and phosphate solubilization were evaluated in selective culture conditions, which had negative results. Indole-3-acetic acid (IAA), gibberellic acid (GA(3)), and abscisic acid (ABA) production were analyzed by gas chromatography-mass spectrometry (GC-MS). Ethylene and zeatin biosynthesis were determined by GS-flame ionization detection and high-performance liquid chromatography (HPLC-UV), respectively. IAA, zeatin, and GA(3) were found in all three strains; however, their levels were significantly higher (p < 0.01) in SEMIA5080 (3.8 microg ml(-1)), USDA110 (2.5 microg ml(-1)), and E109 (0.87 microg ml(-1)), respectively. ABA biosynthesis was detected only in USDA110 (0.019 microg ml(-1)). Ethylene was found in all three strains, with highest production rate (18.1 ng ml(-1) h(-1)) in E109 cultured in yeast extract mannitol medium plus L-methionine. This is the first report of IAA, GA(3), zeatin, ethylene, and ABA production by B. japonicum in pure cultures, using quantitative physicochemical methodology. The three strains have differential capability to produce the five major phytohormones and this fact may have an important technological implication for inoculant formulation.

Carcinogenèse colorectale

Gene alterations which have been implicated in colorectal carcinogenesis are characterized by three major mechanisms: chromosomal instability, microsatellite instability, and epigenetic mechanisms (i.e., CpG island hypermethylation). Progress in understanding of these genetic and epigenetic instabilities has led to advances in the individualization and characterization of more homogeneous sub-groups of colorectal tumors with regard to progression, prognosis and response to therapy.