Protons modulate perivascular axo-axonal neurotransmission in the rat mesenteric artery

Background and Purpose

Previous studies have demonstrated that nicotine releases protons from adrenergic nerves via stimulation of nicotinic ACh receptors and activates transient receptor potential vanilloid-1 (TRPV1) receptors located on calcitonin gene-related peptide (CGRP)-containing (CGRPergic) vasodilator nerves, resulting in vasodilatation. The present study investigated whether perivascular nerves release protons, which modulate axon-axonal neurotransmission.

Experiment Approach

Perfusion pressure and pH levels of perfusate in rat-perfused mesenteric vascular beds without endothelium were measured with a pressure transducer and a pH meter respectively.

Key Results

Periarterial nerve stimulation (PNS) initially induced vasoconstriction, which was followed by long-lasting vasodilatation and decreased pH levels in the perfusate. Cold-storage denervation of the preparation abolished the decreased pH and vascular responses to PNS. The adrenergic neuron blocker guanethidine inhibited PNS-induced vasoconstriction and effects on pH, but not PNS-induced vasodilatation. Capsaicin (CGRP depletor), capsazepine and ruthenium red (TRPV1 inhibitors) attenuated the PNS-induced decrease in pH and vasodilatation. In denuded preparations, ACh caused long-lasting vasodilatation and lowered pH; these effects were inhibited by capsaicin pretreatment and atropine, but not by guanethidine or mecamylamine. Capsaicin injection induced vasodilatation and a reduction in pH, which were abolished by ruthenium red. The use of a fluorescent pH indicator demonstrated that application of nicotine, ACh and capsaicin outside small mesenteric arteries reduced perivascular pH levels and these effects were abolished in a Ca²⁺-free medium.

Conclusion and Implication

These results suggest that protons are released from perivascular adrenergic and CGRPergic nerves upon PNS and these protons modulate transmission in CGRPergic nerves.Tables of Links

Molecular Detection of Diphyllobothrium nihonkaiense in Humans,China

The cause of diphyllobothriosis in 5 persons in Harbin and Shanghai, China, during 2008–2011, initially attributed to the tapeworm Diphyllobothrium latum, was confirmed as D. nihonkaiense by using molecular analysis of expelled proglottids. The use of morphologic characteristics alone to identify this organism was inadequate and led to misidentification of the species.     

Non-tuberculous Mycobacterial Pseudo-outbreak of an Intestinal Culture Specimen Caused by a Water Tap in an Endoscopy Unit

Objective Gastrointestinal lesions of non-tuberculous mycobacteria (NTM) are regarded as opportunistic infections. A large number of positive specimens of NTM were identified in an intestinal fluid culture in the endoscopy unit and it was considered to be a pseudo-outbreak. Methods We reviewed the hospital, laboratory, and colonoscopy records of 263 consecutive patients whose intestinal fluids were analyzed for a mycobacterial culture by colonoscopy at St. Marianna University Hospital, between January 2009 and December 2018. The endoscopy reprocessing procedures were reviewed and samples of water used in the endoscopy unit were cultured. Results An intestinal fluid culture of 154 (58.6%) patients tested positive for NTM (M. intracellulare; 125 cases, M. gordonae; 14 cases, M. avium; 4 cases, M. abscessus; 3 cases, and 8 other cases). In 182 cases (69.2%), an intestinal mucosal culture was performed simultaneously with a fluid culture and tested positive for NTM in 2 cases. Next, we examined the endoscopy unit for any possible environmental contamination. NTM were detected in the tap water used to prepare the antifoaming solution in the endoscopy unit. The water faucets in the endoscopy unit were considered to be the source of the contamination of NTMs. Conclusion We observed that a large number of cases tested positive due to contaminated water that had been used in an endoscopy unit, thus leading to a pseudo-outbreak of NTM.     

Thoracoscopic versus open repair of esophageal atresia with tracheoesophageal fistula at a single institution

Purpose

The potential benefits of thoracoscopic repair (TR) of esophageal atresia and tracheoesophageal fistula (EA/TEF) in newborns are still unclear. Our aim was to define the criteria, perioperative outcome after undergoing TR versus open repair (OR) for EA/TEF.

Patients and methods

A retrospective chart review was conducted of 36 consecutive neonates who underwent EA/TEF repair between 2001 and 2012 in Shizuoka Children’s Hospital. Patients in this study were birth weight >2,000 g, and did not have severe cardiac malformations or chromosomal aberrations. Of the 26 newborns who met the selection criteria, 11 patients underwent attempts at TR compared to 15 patients who underwent OR. All cases were followed 1 year after operation at least.

Results

All 11 TR were successfully completed. There were no significant differences between intra- and perioperative complications in the two groups. Intraoperative EtCO₂ and arterial blood gases were not significantly different between the two groups. We did not found eating disorder, respiratory disorder, and failure of growth in all cases.

Conclusion

In our study, the thoracoscopic approach appeared to be favorable and safe for EA/TEF repair in carefully selected patients.     

Human breast milk exosomes attenuate intestinal damage

Pediatric Surgery International - Human breast milk (HBM), which contains an abundant supply of exosomes, is known to prevent necrotizing enterocolitis (NEC). Preterm infants are commonly given...     

Biological effects of rAAV-caAlk2 coating on structural allograft healing.

Structural bone allografts often fracture due to their lack of osteogenic and remodeling potential. To overcome these limitations, we utilized allografts coated with recombinant adeno-associated virus (rAAV) that mediate in vivo gene transfer. Using beta-galactosidase as a reporter gene, we show that 4-mm murine femoral allografts coated with rAAV-LacZ are capable of transducing adjacent inflammatory cells and osteoblasts in the fracture callus following transplantation. While this LacZ vector had no effect on allograft healing, bone morphogenetic protein signals delivered via rAAV-caAlk2 coating induced endochondral bone formation directly on the cortical surface of the allograft by day 14. By day 28 there was evidence of remodeling of the new woven bone and massive osteoclastic resorption of the cortical surface of the rAAV-caAlk2-coated allografts only. Micro-CT analysis of rAAV-LacZ- vs rAAV-caAlk2-coated allografts after 42 days of healing demonstrated a significant increase in new bone formation (0.67 +/- 0.21 vs 2.49 +/- 0.40 mm(3); P < 0.005). Furthermore, the 3D micro-CT images of femurs grafted with rAAV-Alk2-coated allografts provided the first evidence that complete bridging of bone around a cortical allograft is possible. These results indicate that cell-free, rAAV-coated allografts have the potential to revitalize in vivo following transplantation.     

Second Hepatic Resection for Recurrent Hepatocellular Carcinoma in Patients with Chronic Hepatitis C

Background Although a second hepatic resection (SHR) for recurrent hepatocellular carcinoma (HCC) is widely accepted, the indications for SHR have not been established. The risk factors for HCC recurrence after SHR were evaluated to investigate the indications for SHR. Methods Subjects included 51 patients who underwent a second hepatic resection for recurrence of HCV-related HCC. Sixteen patients received interferon therapy before or after the first operation. Six patients attained a sustained viral response (SVR) that was defined as return of the alanine aminotransferase (ALT) activity to within the reference range and no detectable serum HCV RNA for at least 1 year after interferon therapy. A biochemical response (BR), defined as a normalized ALT activity for at least 1 year after interferon therapy with or without the transient disappearance of serum HCV RNA, was attained in three patients. The other seven patients were defined as the nonresponse (NR) group. Results By univariate analysis, NR and lack of interferon therapy, high indocyanine green retention rate at 15 min (ICGR15), high aspartate aminotransferase activity, high ALT activity, large tumor, and multiple tumors were risk factors for HCC recurrence after SHR. By multivariate analysis, NR and lack of interferon therapy, high ICGR15, large tumor, and multiple tumors were independent risk factors. Conclusions Patients in whom active hepatitis has been controlled by interferon therapy are the best candidates for SHR. Interferon therapy should be recommended in patients undergoing resection of an HCV-related HCC because SHR can prolong life in SVR and BR patients.