Transection versus preservation of the neurovascular bundle of the lesser omentum in primary Roux-en-Y gastric bypass surgery.

BACKGROUND: A gastric pouch in Roux-en-Y gastric bypass (RYGB) surgery can be created after transection of the perigastric neurovascular bundle or by preserving these structures. Some surgeons choose to transect the neurovascular bundle (NBT), containing branches of the vagus nerve, because this might be related to additional weight loss, whereas others advocate preservation (NBP) to reduce postoperative complications. OBJECTIVES: This study assessed the effect of both techniques after primary RYGB. SETTING: All patients undergoing primary RYGB in a large bariatric center in the Netherlands between January 2010 and December 2013 were included. METHODS: Patient demographic characteristics, operative details, postoperative complications and weight loss after 1 year were retrospectively analyzed. RESULTS: A total of 773 consecutive patients were included (85.5% female). NBT was performed in 407 patients (52.7%), whereas NBP was performed in 366 patients. There were no missing data and 81.2% of patients completed the 1-year follow-up. Postoperative complications were found in 66 patients (8.5%). A total of 49 patients (6.3%) either had an anastomotic leakage, postoperative bleeding, or intraabdominal abscess (NBT 8.8% versus NBP 3.6%, P = .003). Percentage total weight loss (NBT 34.5%±6.9% versus NBP 33.4%±6.9%; P = .011) differed to a lesser extent between groups, although this was significant. Neurovascular bundle transection was identified as independent factor among others for occurrence of leakage, bleeding, and abscess development (OR 2.886; 95% CI [1.466-5.683]; P = .002). CONCLUSIONS: Transection of the neurovascular bundle in RYGB is associated with more complications. Furthermore, weight loss is not relevantly increased. Further research is necessitated to substantiate these findings.

Increase in visceral fat per se does not induce insulin resistance in the canine model.

OBJECTIVES: To determine whether a selective increase of visceral adipose tissue content will result in insulin resistance. METHODS: Sympathetic denervation of the omental fat was performed under general inhalant anesthesia by injecting 6-hydroxydopamine in the omental fat of lean mongrel dogs (n = 11). In the conscious animal, whole-body insulin sensitivity was assessed by the minimal model (SI ) and the euglycemic hyperinsulinemic clamp (SICLAMP ). Changes in abdominal fat were monitored by magnetic resonance. All assessments were determined before (Wk0) and 2 weeks (Wk2) after denervation. Data are medians (upper and lower interquartile). RESULTS: Denervation of omental fat resulted in increased percentage (and content) of visceral fat [Wk0: 10.2% (8.5-11.4); Wk2: 12.4% (10.4-13.6); P < 0.01]. Abdominal subcutaneous fat remained unchanged. However, no changes were found in SI [Wk0: 4.7 (mU/l)(-1) min(-1) (3.1-8.8); Wk2: 5.3 (mU/l)(-1) min(-1) (4.5-7.2); P = 0.59] or SICLAMP [Wk0: 42.0 × 10(-4) dl kg(-1) min(-1) (mU/l)(-1) (41.0-51.0); Wk2: 40.0 × 10(-4) dl kg(-1) min(-1) (mU/l) (-1) (34.0-52.0); P = 0.67]. CONCLUSIONS: Despite a selective increase in visceral adiposity in dogs, insulin sensitivity in vivo did not change, which argues against the concept that accumulation of visceral adipose tissue contributes to insulin resistance.

Chitosan scaffold enhances nerve regeneration within the in vitro reconstructed bladder wall: an animal study.

INTRODUCTION: The function of reconstructed bladder depends on the contracting bladder wall. This can be obtained with a proper innervating segment. Polyglycolic acid (PGA) is used as cell vehicle. Chitosan supported the adhesion and differentiation of neurons. The aim of the study was to compare PGA with PGA/chitosan 'sandwich' grafts for bladder regeneration. METHODS: 3T3 fibroblasts were seeded on 6 PGA and on 3 chitosan scaffolds and incubated for 3 days at 37 degrees C in 5% CO(2) before implantation. Three rats underwent bladder reconstruction with PGA cell-seeded grafts and 3 with PGA grafts covered with chitosan cell-seeded grafts ('sandwich' graft). Three rats in the control group were not operated. After 6 months, reconstructed tissue was stained with hematoxylin and eosin. Neurons were identified by synaptophysin and neuron-specific enolase staining. RESULTS: No complications were noticed. PGA/chitosan grafts were evaluated as (+++) and (++), while PGA grafts were evaluated as (++) and (+) with use of synaptophysin antibody. The control group was evaluated as (+). PGA/chitosan grafts were evaluated as (++) and (+), while PGA grafts were evaluated as (++) and (+) in neuron-specific enolase staining. The control group was evaluated as (+). CONCLUSION: Chitosan improved PGA's abilities as a cell matrix and in guiding neurons into the graft.

Catecholamines in paraganglia associated with the hepatic branch of the vagus nerve: effects of 6-hydroxydopamine and reserpine.

Paraganglia are clusters of cells containing catecholamines (CA), mainly norepinephrine (NE) and dopamine (DA). The presence of epinephrine (E), on the other hand, has only been determined by indirect methods in retroperitoneal paraganglia of newborn and aged rats. Because their location, paraganglia associated with the hepatic branch of the vagus nerve may be a possible source of CA for the liver. The main purposes of the present study were to determine CA levels and whether E can be found in the omentum minus which includes paraganglia associated with the hepatic branch of the vagus nerve, and then to study the effects of 6-hydroxydopamine and reserpine on their CA content. Twenty-four female Wistar rats were randomly ascribed to three groups receiving two intraperitoneal injections of either 6-hydroxydopamine, reserpine or saline. Twenty-four hours after the last administration the rats were anesthetized and a portion of the omentum minus was obtained. Left adrenal medulla and a liver fragment were also collected as controls. The samples were processed to be analyzed by high performance liquid chromatography and catecholamine histofluorescence. The results confirm previous reports about the presence of considerable amounts of norepinephrine and dopamine in paraganglia. Norepinephrine and dopamine in the omentum like the adrenal medulla were significantly depleted by reserpine but not by 6-hydroxydopamine treatment, suggesting that some other sources in addition to sympathetic terminals are responsible for CA in the omentum. On the contrary, both drugs reduced liver NE, consistent with the localization of this amine mainly to hepatic sympathetic terminals. Histofluorescence of the omentum revealed 2-4 paraganglia per tissue fragment. Paraganglia associated with the hepatic branch of the vagus nerve contain also E. The presence of perihepatic sources of extra-adrenal CA, and more specifically E, could be of physiological significance.

An ultrastructural study of dopamine-immunoreactive nerve fibres in milky spots of the human greater omentum.

An ultrastructural study was performed to examine the presence and distribution of dopamine-immunoreactive nerve fibres in milky spots of the human greater omentum. Non-myelinated nerve fibres were located perivascularly as well as throughout the milky spots. Dopamine immunoreactivity was demonstrated in the nerve fibres and in a portion of the macrophage population. These results demonstrate a discrepancy between human and non-human milky spots.

Pyloroplasty divides vagus nerve fibers to the greater curvature of the stomach. An axonal tracing study.

Recent studies have demonstrated the location in the dorsal motor nucleus of the vagus nerve (dmnX) of nerve cells that project preganglionic efferent vagus nerve fibers to the greater curvature of the stomach. Although it is clear that these fibers are contained within the vagus nerve trunks, the intra-abdominal pathways of these fibers are unknown. When a neurotracer was applied to the right gastroepiploic pedicle, nerve cells in the bilateral dmnX were labeled. If a preliminary anterior or posterior pyloroplasty was performed before the application of the neurotracer, cellular labeling was seen on the right or left side of the dmnX, respectively. Furthermore, division of the anterior Latarjet nerve eliminated labeling in cells of the left dmnX. This study demonstrates that the preganglionic vagus nerve fibers within the right gastroepiploic pedicle traverse an intramural course across the pylorus and are contained in the Latarjet nerve.

Solid ovarian teratoma with neuroglial metastases to periaortic lymph nodes and omentum.

We have described a 16-year-old girl who had a unilateral adnexectomy for a solid ovarian teratoma, grade 0. Periaortic nodes and omentum contained grade 0 neuroglial metastases.

Tension receptors with vagal afferent fibres in the proximal duodenum and pyloric sphincter of sheep.

Single-unit afferent activity was recorded from the hepatic-duodenal branch of the vagus nerve of chloralose-anaesthetized sheep during acute electrophysiological experiments. The impulse activity of sixty-seven slowly adapting mechanoreceptors situated in the muscularis externa of the proximal duodenum and pyloric sphincter was synchronous with alterations in electromyographic and tension records. Afferent units were excited during passive distension, compression and drug-induced increases in muscle tension, thus satisfying the criteria for 'in series' tension receptors (Iggo, 1955). From the responses to compression some evidence was found for the existence of separate populations of tension receptors with different mechanical thresholds. Two fibre populations were found: non-myelinated (0.70 +/- 0.26 S.D. ms-1) and myelinated (7.6 +/- 1.6 S.D. m s-1). Mucosal application of solutions of hydrochloric acid, volatile fatty acids, alkali and amino acids, and mucosal probing modified the activity of most units. These changes were reduced by anaesthesia of the mucosa. It is concluded that tension receptors in the sheep duodenum occupy a position 'in series' with longitudinal muscle, and that their activity can be modified by the particulate and chemical composition of chyme by a mechanism involving local nerve plexuses. The activity of tension receptors is compared with that of two other mechanoreceptor classes located serosally (five units) and in the lesser omentum (eleven units). Receptors in neither of these two classes were directly excited by active contraction of the duodenum.

Reflex adrenergic inhibition of gastric motility by nociceptive intestinal stimulation and peritoneal irritation in the cat.

The effects on gastric motility of nociceptive stimulation to jejunum and colon were studied in vagotomized anesthetized cats. Mechanical nociceptive stimulation and diathermy of the jejunum and proximal colon elicited reflex gastric inhibition that was significantly more pronounced than that obtained by stimulation of distal colon. Similarly differentiated reflex responses were induced by electric afferent stimulation of nerves from the respective intestinal segments. Strong nociceptive stimuli from the abdominal cavity, induced by peritonitis, completely blocked vagal excitatory influences on gastric motility, as did multiple nerve stimulation. The gastric inhibitory response to abdominal irritation persisted after adrenalectomy but was eliminated during spinal anesthesia or adrenergic blockade. During gastric suppression in animals with abdominal peritonitis cholinergic potentiation with synstigmin administration could only modestly increase gastric tone. It is concluded that intestinal nociceptive stimulation causes gastric inhibition via sympathetic reflex arches that are segmentally differentiated. These adrenergically mediated inhibitory reflexes are powerful enough to block completely myenteric cholinergic neurons. The results suggest that adrenergic blockade or spinal anesthesia is the logical procedure for treating postoperative adrenergic gastric inhibition. The presently studied sympatho-sympathetic adrenergic reflexes seem to work in synergism with sympatho-vagal nonadrenergic reflexes in suppressing gastric motility during paralytic ileus.

Ultrastructural features of mast cells in human omental veins.

Mast cells are relatively common in human omental veins where they generally occur in the tunica adventitia and among the peripheral smooth muscle cells of the tunica media. The distance between mast cells and adjacent muscle cells is often as short as 1 micrometer. The tunica intima does not contain mast cells. With few exceptions the typical mast cells were oval in shape, had numerous slender projections and contained granules (0.3-0.7 micrometer) with characteristic stacks of lamellae and scrolls. A few elongated cells with processes containing granules filled with dense homogeneous matrix material were also detected and could represent so-called chromaffin mast cells. Noradrenergic axons and terminals identified by their large (85 nm) and small (50 nm) dense-cored vesicles are present in the vicinity of many mast cells which could allow various interactions between the two cell types and their released amines and ATP. Electrical field stimulation which affects the nerve terminals does not change the ultrastrcutre of the mast cells unless the alpha-blocking agent phentolamine (7.5 X 10-7 M) is present during the stimulation, when degranulation results.

Ultrastructure of the nerves in veins from human omentum.

To study the ultrastructural characteristics of the sympathetic nerve terminals of human omental veins, and of their relationship to the innervated smooth muscle cells, biopsy specimens were taken during abdominal surgery, rapidly fixed in glutaraldehyde/osmium and stained with uranylacetate. The results indicate that the veins have an extensive noradrenergic innervation, penetrating into the tunica media. The distance between nerve terminals partly or wholly free from enveloping Schwann cells, to the surface of smooth muscle cells ranged from 30 to 500 nm. Large dense core vesicles were prominent in both preterminals and terminal regions, while small dense core vesicles occurred mainly in terminals. Large dense core vesicles in close contact with the axolemma were occasionally observed, indicating involvement in secretion by exocytosis.

Splanchnic slowly adapting mechanoreceptors with punctate receptive fields in the mesentery and gastrointestinal tract of the cat.

1. A class of slowly adapting mechanoreceptors with A-delta and C fibres running in the splanchnic nerves of cats is described.2. The mechanoreceptors have punctate regions of mechanical sensitivity at macroscopic vascular branching points and have been found in the lesser omentum, the mesentery of the gall-bladder, porta hepatis, portal vein, pancreas, spleen and the duodenum, jejunum, ileum, colon and their mesenteries.3. The receptive fields of these mechanoreceptors vary considerably in size in the different regions. The largest receptive fields were found in the small intestinal mesentery and consisted of up to seven points of mechanical sensitivity at vascular divisions, each separated by distances of a few up to about 40 mm. The smallest receptive fields were single or double points of mechanical sensitivity which were most commonly found in relation to the portal vein in the root of the mesentery.4. Maintained stretch of the receptive field elicited a train of impulses which had phasic and tonic components. The tonic discharge was sometimes maintained for more than 1 min.5. Distension of a neighbouring viscus often caused a discharge which had a phasic component and a variable tonic component. The occurrence of the latter appeared to depend on the relative positions of the bowel and mesentery, and was probably associated with a change in tension on the mesentery.6. Occlusion of the portal vein resulted in some units in a discharge which began soon after the start of the occlusion.7. The receptors do not appear to be affected by acid, hypoxia or hypercapnia.