Pontamine sky blue: a counterstain for background autofluorescence in fluorescence and immunofluorescence histochemistry

The stain pontamine sky blue (PSB) has been shown to reduce background autofluorescence in catecholamine fluorescence and immunofluorescence histochemical preparations. Using PSB as a counterstain on whole-mount stretch preparations of human mesenteric blood vessels, a medium dense noradrenergic nerve plexus is clearly revealed, which previously had been only partially visible because of background autofluorescence. Image analysis of nerve densities in whole-mount stretch preparations of guinea-pig arteries containing noradrenergic, substance P-, and vasoactive intestinal polypeptide (VIP)-positive nerve plexuses shows that PSB staining does not alter the specific neuronal fluorescence and that it improves image definition.

Simvastatin inhibits inflammatory properties of Staphylococcus aureus alpha-toxin

BACKGROUND

Simvastatin, a 3-hydroxy-methylglutaryl coenzyme A reductase inhibitor, has been shown to lower serum cholesterol levels in clinical use. Moreover, statins exert beneficial effects in vascular diseases by inhibition of leukocyte rolling, adherence, and transmigration. The aim of this study was to determine if pretreatment with simvastatin attenuates Staphylococcus aureus alpha-toxin-induced increase in leukocyte-endothelial interactions during exotoxemia.

METHODS AND RESULTS

The effects of simvastatin on leukocyte-endothelial cell interactions were observed by intravital microscopy in the rat mesenteric microcirculation. Simvastatin (50 or 100 microg/kg) was administered 18 hours before the study. Activation of microcirculation was induced by bolus administration of 40 microg/kg S aureus alpha-toxin. Exotoxemia resulted in a significant and time-dependent increase in leukocyte rolling, adherence, and transmigration of leukocytes as well as P-selectin expression on the intestinal vascular endothelium. Pretreatment with simvastatin significantly inhibited exotoxin-induced leukocyte rolling from 71+/-10 to 14+/-4.7 cells/min (P<0.01) and adherence from 14+/-3.5 to 0.4+/-0.2 cells (P<0.01). In addition, simvastatin pretreatment significantly inhibited transmigration of leukocytes from 10.5+/-1.2 to 4.2+/-0.9 (P<0.05) cells. Immunohistochemical detection of endothelial cell adhesion molecule P-selectin showed a 50% decrease in endothelial cell surface expression after simvastatin treatment. Furthermore, simvastatin treatment resulted in enhanced expression of endothelial cell NO synthase III in the intestinal microcirculation.

CONCLUSIONS

These results demonstrate that simvastatin interferes with exotoxin-induced leukocyte-endothelial cell interactions, which may be relevant in various infectious diseases. Statin treatment may offer a new therapeutic strategy for these clinical conditions.

Correlation of the directly observed responses of mesenteric vessles of the rat to nerve stimulation and noradrenaline with the distribution of adrenergic nerves

1. The effects of nerve stimulation and of the topical application of noradrenaline on arteries, capillaries and veins of the mesentery of the anaesthetized rat were examined by direct observation under a microscope. The distribution of adrenergic nerves to the vessels of the mesentery was studied using the fluorescence histochemical method.2. Principal arteries, small arteries and terminal arterioles were all innervated by a network of adrenergic fibres and they all constricted in response to the stimulation of paravascular nerves and to exogenous noradrenaline. Few adrenergic fibres accompanied the smaller, precapillary arterioles; these vessels did not respond to nerve stimulation, although they were constricted by concentrations of noradrenaline as low as 10(-10) g/ml.3. The capillaries did not respond to nerve stimulation or to applied noradrenaline. All veins were constricted by noradrenaline, but only those veins greater than about 30 mum in internal diameter responded to nerve stimulation.4. At stimulus frequencies greater than 4 Hz the flow of blood through the microvasculature usually ceased, although there was never complete closure of these vessels. The maximum constriction observed in principal arteries was usually between 50 and 70% of the control internal diameter, and in small arteries and terminal arterioles was between 40 and 65% of the control internal diameter.5. It is concluded that the principal arteries and small arteries of the mesenteric vasculature are important in the control of blood flow through this vascular bed during sympathetic stimulation and following topical application of noradrenaline, and that the precapillary arterioles are important vessels determining the rate of blood flow through the capillary bed under resting conditions.

Volume-rendered 3D CT of the mesenteric vasculature: normal anatomy, anatomic variants, and pathologic conditions

Multi-detector row computed tomography (CT) offers important advantages over more conventional imaging methods in the evaluation of the mesenteric vasculature. It allows faster scanning, which practically eliminates motion and breathing artifacts, as well as thinner collimation. These advances, coupled with rapid intravenous administration of contrast material, allow excellent opacification of the mesenteric arteries and veins. This improves the quality of the three-dimensional (3D) data sets, which in turn leads to improved 3D vascular maps and more accurate assessment of various conditions such as arterial or venous encasement in patients with pancreatic cancer, mesenteric ischemia, or inflammatory bowel disease. Three-dimensional multi-detector row CT also allows better visualization of arterial and venous branching, thereby improving detection of more distal vascular involvement. In addition, 3D multi-detector row CT may help detect hemodynamic changes in patients with active inflammation and hyperemia of a bowel segment because it can be used to measure bowel wall enhancement over time. Carcinoid tumors that have infiltrated the mesentery have a characteristic CT appearance, and other conditions such as lymphoma or sclerosing mesenteritis can also manifest as an infiltrating mass that envelops mesenteric vessels. Three-dimensional multi-detector row CT represents a significant advance in CT technology and can help ensure prompt, accurate evaluation of the mesenteric vasculature.

Anatomy of the splanchnic circulation

The blood supply to the intestines is a complex one, including branches of the three main splanchnic arteries as well as a vast collateral circulation. The variant anatomy and collateral pathways are described, based on anatomic dissections and angiographic studies, to focus attention on anatomically based explanations for clinical entities.

Anatomic study of the superior right colic vein: its relevance to pancreatic and colonic surgery

BACKGROUND

This study was designed to describe the precise anatomic venous tributaries of the superior mesenteric vein with special emphasis on the superior right colic vein (SRCV), which is seldom mentioned in the literature.

METHODS

Nine adult cadavers were dissected to define the venous tributaries of the superior mesenteric vein. The SRCV, middle colic vein, and right colic vein (RCV) were defined as those that drained from the marginal vein of the right flexure of the colon, the transverse colon, and the ascending colon, respectively.

RESULTS

The SRCV was observed to drain from the right flexure of the colon to the confluence of the right gastroepiploic and superior pancreaticoduodenal veins and present the gastrocolic trunk of Henle (GTH) in 8 of 9 cases. The RCV terminated into the GTH in 4 cases. The SRCV, the RCV, and the middle colic vein formed a confluence and entered into the GTH in 1 case.

CONCLUSIONS

The SRCV exits and drains from the right colonic flexure to the GTH in 89% of cases.

Mesenteric circulation: three-dimensional MR angiography with a gadolinium-enhanced multiecho gradient-echo technique

To evaluate the mesenteric circulation with magnetic resonance (MR) angiography, the authors examined 16 individuals (12 patients, four volunteers) with a gadolinium-enhanced, breath-hold, fat-saturated, multiecho, three-dimensional, gradient-echo sequence. Twenty examinations were performed. Grades of 3 or 4 (on a five-point scale [4 = best seen, 0 = not seen]) were applicable to 17 (85%) of 20 MR angiograms obtained in superior mesenteric artery trunks, 15 (75%) in celiac arteries, five (25%) in inferior mesenteric arteries; 15 (75%) of first-order branching, 12 (60%) of second-order branching, and 10 (50%) of third-order branching; 17 (85%) in superior mesenteric veins; and 17 (85%) in portal veins. MR angiography with this technique depicted the mesenteric arterial and venous circulation and the portal vein with excellent resolution in a short time.

Simultaneous measurements of radii and wall thickness of microvessels in the anesthetized rat

The purpose of this investigation was to measure the radius and wall thickness of small blood vessels in mesentery and striated (cremaster) muscle in the anesthestized rat. Using the method of image-splitting, the vessel images were sheared at magnifications of 3,OOOx and 6,500x on the video screen.

In the resting state, the mean lumen values for the thinnest portion of endothelial capillary were 4.1 ± 1.2µ (SD) in cremaster and 5.6 ± 1.3µ (SD) in mesentery. Lumen and total diameter were also greater at several levels of precapillary arterioles in mesentery than similar vessels in cremaster, suggesting that smaller vessel size in cremaster might be characteristic of this tissue. Vasoconstriction of up to 50% from resting state is associated with an increase in wall thickness and a decrease in lumen to wall ratio due to a disproportional decrease in radius (inner greater than outer radius). Similarly, an increase in vessel radius in a proportion 4 to 1 (inner greater than outer) was sustained up to about 60% of vasodilatation.

In 13 out of 14 vessels, little or no change in wall cross-sectional area occurred in the face of marked changes in lumen cross-sectional area (–95%,+205%). This strongly suggests that other modifications such as changes in length, swelling, or shrinkage would be relatively unimportant during dynamic changes in wall thickness.

Topological structure of rat mesenteric microvessel networks

Microvascular lengths, diameters, and flow directions were determined in all vessel segments (n = 1303) between bifurcations in three complete rat mesenteric microvessel networks (25 mm2 each) using intravital video- and photomicroscopy. The classification of vessel segments as arteriolar, venular, or av-segments (all segments connecting the arteriolar to the venular tree) was based on purely topological criteria. The topological structure of the networks was analyzed using the Horton-Strahler technique and a new generation scheme. Generation numbers were assigned to the vessel segments on the basis of the number of upstream (in the arteriolar tree) and downstream (in the venular tree) bifurcations. The mean generation number of the av-segments, a characteristic parameter of the generation scheme, reflects the topological structure of the network more accurately than Horton's branching ratio Rb. Both the arteriolar and venular tree of the mesenteric networks were found to be dichotomous branching structures which were neither strictly symmetric nor strictly asymmetric. The topological information obtained was compared to network models generated by different random branching algorithms. The result of this comparison suggests that the network structure changes at a certain generation level. Distal to this generation level, the mesenteric networks resemble a model network generated by random branching at any segment, while the proximal portion is similar to a model allowing random branching at terminal segments only.

Surgical Anatomy of the Superior Mesenteric Vessels Related to Colon and Pancreatic Surgery: A Systematic Review and Meta-Analysis

The surgeon dissecting the base of the mesenterium, around the superior mesenteric vein (SMV) and artery, is facing a complex tridimensional vascular anatomy and should be aware of the anatomical variants in this area. The aim of this systematic review is to propose a standardized terminology of the superior mesenteric vessels, with impact in colon and pancreatic resections. We conducted a systematic search in PubMed/MEDLINE and Google Scholar databases up to March 2017. Forty-five studies, involving a total of 6090 specimens were included in the present meta-analysis. The pooled prevalence of the ileocolic, right colic and middle colic arteries was 99.8%, 60.1%, and 94.6%, respectively. The superior right colic vein and Henle trunk were present in 73.9%, and 89.7% of specimens, respectively. In conclusion, the infra-pancreatic anatomy of the superior mesenteric vessels is widely variable. We propose the term Henle trunk to be used for any venous confluence between gastric, pancreatic and colic veins, which drains between the inferior border of the pancreas and up to 20 mm downward on the right-anterior aspect of the SMV. The term gastrocolic trunk should not be synonymous, but a subgroup of the Henle trunk, together with to gastropancreatocolic, gastropancreatic, or colopancreatic trunk.

Anatomic variants of mesenteric veins: depiction with helical CT venography

OBJECTIVE

The purpose of this study was to describe the variable anatomy of mesenteric veins on axial CT images and on volume-rendered CT venograms that use maximum intensity projection and shaded-surface display.

SUBJECTS AND METHODS

Fifty-seven patients undergoing helical CT of the pancreas were included in the study. The mesenteric venous system was analyzed in 54 patients. Three patients were excluded because the helical CT data were unsatisfactory.

RESULTS

On helical CT with maximum intensity projection and shaded-surface display, the superior mesenteric vein (SMV) was seen as a single trunk of variable length in 40 patients. In seven other patients, two mesenteric trunks merged separately with the splenic vein. In the remaining seven patients, the SMV was occluded by tumor. The inferior mesenteric vein drained into the splenic vein in 28 patients (56%), into the SMV in 14 patients (26%), and into the splenomesenteric angle in nine patients (18%).

CONCLUSION

Both axial and volume-rendered CT venograms accurately reveal the variable mesenteric venous anatomy. CT venograms may replace conventional angiography in presurgical planning.

Vascular relationships in right colectomy for cancer: clinical implications

AIMS

The study aim was to provide data on pattern and length of crossing of the ileocolic artery (ICA) and right colic artery (RCA) with the superior mesenteric vein (SMV).

METHODS

Specimens from 30 fresh human cadavers underwent corrosion casting. Methylacrylate was injected into the SMV and superior mesenteric artery (SMA). Length of crossing was measured with a scaleable ruler and copper wire. Values are mean (SD; range).

RESULTS

ICA was present in all specimens and crossed posterior to the SMV in 19 (63.33%) of 30 specimens. Length of crossing was 17.01 (7.84; 7.09-42.89) mm. RCA was present in 19 (63.33%) of 30 specimens. RCA crossed anterior to SMV in 16 (84.21%) of 19 specimens. Length of crossing was 20.63 (8.09; 6.3-35.7) mm.

CONCLUSIONS

ICA was always present, crossed posterior to SMV in 60% of specimens with a crossing length of 17 mm. RCA was present in 63% of specimens, crossed anterior to the SMV in 84% of specimens with a crossing length of 20 mm. Clinical implications include arterial length left behind with main nodes, arterial bleeding and safety of laparoscopic access.

The gastrocolic trunk of Henle in pancreatic surgery: an anatomo-clinical study

From 37 peroperative and cadaver anatomical investigations, it was concluded that, in contrast to the information in common texts on anatomy and surgery, a venous gastrocolic trunk was observed in only 46% of subjects; a true bipod gastrocolic trunk of Henle was a rare (8%) phenomenon. In this respect, a variate venous anatomy at the inferior border of the neck of the pancreas, as observed in this study, must be taken into account during pancreatic surgery and radiological procedures in the pancreas.

Vascular anatomy for right colon lymphadenectomy

Since the superior mesenteric artery (SMA) mostly originates on the left side of the superior mesenteric vein (SMV), the ileocolic artery (ICA) and the right colic artery (RCA) cross the SMV. Understanding the three-dimensional relation of these vessels is important for dissecting these arteries to their origin. Hence, we conducted a study of the vascular anatomy of the right colon in 27 cadavers. The RCA was separate from the SMA in eight cases (30%). The RCA passed the SMV either anteriorly (5 cases, 63%) or posteriorly (3 cases, 38%). In seven (88%) of these eight cases, the ICA was posterior to the SMV. The ICA was identified in all 27 cases, and passed the SMV anteriorly in nine cases (33%) and posteriorly in 18 cases (67%). Thus, the ICA and the RCA may pass on either side of the SMV. The surgeon must dissect the arteries with the SMV, being aware of both possibilities.

Venous anatomy of the right colon: three-dimensional topographic mapping of the gastrocolic trunk of Henle

BACKGROUND

The gastrocolic trunk of Henle has not been described in detail in context with right hemicolectomy. The aim of this study was to define the caliber, length and three-dimensional position of the gastrocolic trunk of Henle (GTH).

METHODS

We studied 10 fresh (<24 h) cadavers. A corrosion cast method was employed. Cold polymerized methylacrylate was injected into the superior mesenteric vein (SMV) and artery. GTH diameter, length and point of confluence with the SMV were assessed.

RESULTS

The GTH was present in all specimens originating from the confluence of the right gastroepiploic and superior-anterior pancreaticoduodenal veins. The GTH joined the SMV at an average distance of 2.2 cm (range, 1.6-3.2 cm) from the inferior pancreatic border and it coursed towards the right side in a ventral-cranial direction. The mean caliber and length of the GTH were 5.2 mm (range, 4.8-5.8 mm) and 16.1 mm (range, 10.1-20.7 mm), respectively.

CONCLUSIONS

The GTH is a short, medium-sized vessel of potential clinical significance with a consistent ventral-cranial direction.

MR angiography of the mesenteric vasculature

MRA has evolved from a research tool to a robust clinical diagnostic modality. In many centers worldwide, it is the technique of choice for evaluating patients with suspected CMI, assessing operability of patients with pancreatic cancer, and investigating the portal system. Evolving indications include the assessment of liver transplant patients before and after transplant and of living related liver transplant donors. The search for the bleeding source in patients with gastrointestinal hemorrhage may be an indication in the future, once intravascular contrast agents become available.

Ultrasound demonstration of changes in the normal portal venous system following a meal

Eating might be expected to change vessel size within the portal venous system. The diameters of the portal and superior mesenteric veins were measured in thirteen normal individuals using B-mode ultrasound, initially fasting and then following a meal. We have shown a 50% increase in the diameter of both these vessels occurring between thirty minutes and one hour after a meal. The significance of this is discussed.

Gastrocolic trunk of Henle and its variants: review of the literature and clinical relevance in colectomy for right-sided colon cancer

PURPOSE

Venous vascular anatomy of the right colon presents a high degree of variability. Henle's Gastrocolic Trunk is considered an important anatomical landmark by colorectal surgeons. The classical description concerns a bipod vascular structure or tripod, but several variants are associated to it. The aim of this study is to merge the most updated literature on the anatomy knowledge of the Gastrocolic Trunk by evaluating all possible variants, as well as to underline its surgical importance due to its topographical relationships.

METHODS

Twelve studies describing the anatomy of the gastrocolic trunk were selected, each of them dealing with a more or less extensive series of cases. A distinction was drawn between the gastropancreatic trunk, devoid of the colonic component, and the gastrocolic trunk; and then the frequency of the different resulting variants was reported. The data obtained from cadavers and radiological studies were analyzed separately.

RESULTS

The Gastrocolic Trunk is found in 74% of cadaver studies, and in 86% of radiological studies. Its most frequent configuration is represented by the union of right gastroepiploic vein + anterior superior pancreaticoduodenal vein + superior right colic vein, respectively, 32.5% and 42.5%, followed by the right colic vein which replaces (26.9%, 12.3%) or is added (10%, 20.1%) to the superior right colic vein.

CONCLUSIONS

The superior right colic vein joins the right gastroepiploic vein and the anterior superior pancreaticoduodenal vein thus forming, in most cases, the gastrocolic trunk. The anatomical knowledge of vascular structures forms the basis for both the interpretation of preoperative radiological images and the surgical procedure itself, despite the considerable anatomical variability of tributaries.

Vascular anatomy of inferior mesenteric artery in laparoscopic radical resection with the preservation of left colic artery for rectal cancer

AIM

To investigate the vascular anatomy of inferior mesenteric artery (IMA) in laparoscopic radical resection with the preservation of left colic artery (LCA) for rectal cancer.

METHODS

A total of 110 patients with rectal cancer who underwent laparoscopic surgical resection with preservation of the LCA were retrospectively reviewed. A 3D vascular reconstruction was performed before each surgical procedure to assess the branches of the IMA. During surgery, the relationship among the IMA, LCA, sigmoid artery (SA) and superior rectal artery (SRA) was evaluated, and the length from the origin of the IMA to the point of branching into the LCA or common trunk of LCA and SA was measured. The relationship between inferior mesenteric vein (IMV) and LCA was also evaluated.

RESULTS

Three vascular types were identified in this study. In type A, LCA arose independently from IMA (46.4%, n = 51); in type B, LCA and SA branched from a common trunk of the IMA (23.6%, n = 26); and in type C, LCA, SA, and SRA branched at the same location (30.0%, n = 33). The difference in the length from the origin of IMA to LCA was not statistically significant among the three types. LCA was located under the IMV in 61 cases and above the IMV in 49 cases.

CONCLUSION

The vascular anatomy of the IMA and IMV is essential for laparoscopic radical resection with preservation of the LCA for rectal cancer. To recognize different branches of the IMA is necessary for the resection of lymph nodes and dissection of vessels.