Musculo-fibrous anomaly in Barrett's mucosa with dysplasia

We investigated the histological alterations occurring in the muscularis mucosae, the lamina propria mucosae, and the submucosa in areas adjacent to invasive adenocarcinoma in 32 resected esophagi with Barrett's mucosa. In 26 of the 32 specimens, we observed a thickening of the muscularis mucosae, with overgrowth of the muscle fibers into the lamina propria mucosae. In other areas, collagen-rich fibrotic tissue replaced the muscularis mucosae, the lamina propria mucosae, and even the submucosa. In 31 of the 32 specimens, we noted cystic dilatations of the esophageal glands. Normal esophageal glands and cystically dilated glands with dysplastic lining were often surrounded, compressed, and deformed by the fibrotic tissue. The compression of the glandular outlets by the collagen-rich tissue or by proliferating dysplastic cells appeared to be the two main factors in the histogenesis of these cysts. This may result in difficulty in differentiating, in biopsy specimens, between normal and dysplastic esophageal glands "trapped" in the collagen-rich fibrotic tissue and true invasive adenocarcinoma in the Barrett's mucosa.     

Distribution of blood flow in the intestine with hypertonic glucose in the lumen.

The effects of luminal placement of 50 percent glucose solution on distribution of blood flow within the jejunal wall were studied with radioactive microspheres. Two types of spheres, 15 +/- 5 mu in diameter, were used. One was labeled with cerium- 141 (Ce- 141) and the other with strontium-85 (Sr-85). They were injected sequentially to test for reproducibility of the results. These two types of spheres gave similar results qualitatively and quantitatively. Luminal placement of 50 percent glucose increased total blood flow to the jejunal wall but the increase occurred mainly in the mucosal layer. The flow to the submucosa or muscularis-serosa was not altered. This increased mucosal flow was attenuated by prior exposure of the mucosa to a local anesthetic, dibucaine. It is suggested that the increased intestinal blood flow that occurs in the experimental dumping syndrome is confined to the mucosa of the intestine and is mediated by mechanisms that can be inhibited by exposing the mucosa to a local anesthetic.     

Microsphere intestinal blood flow analysis during pneumoperitoneum using carbon dioxide and helium

Background Pneumoperitoneum has been associated with a decreased flow in the superior mesenteric artery and portal venous system. Intestinal blood flow was studied during a 2-h pneumoperitoneum with carbon dioxide (CO₂) or helium in a porcine model using colored microspheres.Methods For this study, 12 pigs were divided into two groups (6 CO₂ and 6 helium). Different colored microspheres were injected directly into the left ventricle before, 40, 80, and 120 min after insufflation with either gas at a pressure of 15 mmHg. Microsphere concentration was measured in the mucosa and muscularis/serosa layers of the jejunum, cecum, and sigmoid colon to calculate blood flow.Results Intestinal perfusion initially increases with insufflation and returns to near baseline levels during pneumoperitoneum of 2 h. The effect of helium on tissue perfusion is similar to that of carbon dioxide.Conclusions Intestinal perfusion does not change significantly during prolonged pneumoperitoneum at a pressure of 15 mmHg with CO₂ or helium.Podium presentation at the 2004 meeting of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), Denver, Colorado, USA, 31 March-3 April, 2004     

Determination of regional bone blood flow by means of fluorescent microspheres using an automated sample-processing procedure

The determination of regional blood flow utilizing fluorescent microspheres (FMs) is an established method for numerous organs. Recent progress, in particular the automation of sample processing, has further improved this method. However, the FM method (reference sample technique), which allows repetitive measurement of regional organ blood flow, has so far not been used for the determination of blood flow in bone. The aim of the present study was to establish FM for the quantification of regional bone blood flow (RBBF). Female, anesthetized New Zealand rabbits (n = 6) received left ventricular injections of different amounts of FM at six subsequent time points. In order to examine the precision of RBBF determination, two different FM species were injected simultaneously at the sixth injection. At the end of the experiments the femoral and tibial condyles of each hind limb were removed and the fluorescence intensity in the tissue samples was measured by an automated procedure. In an in vitro study we have shown that acid digestion of the crystalline matrix has no effect on the fluorescence characteristics of FM. The determination of the number of spheres per tissue sample revealed that depending on the tissue sample size up to 3 x 10(6) spheres/injection were necessary to obtain about 400 microspheres in the individual bone samples. RBBF values of the tibial and femoral condyles did not differ at various injection intervals. The tibial blood flow values varied between 6.6 +/- 1.1 and 8.5 +/- 1.4 ml/min/100 g and were significantly higher than those of the femur (4.3 +/- 1.1 to 6.0 +/- 1.8 ml/min/100 g). The bone blood flow values obtained by simultaneous injection of two FM species correlated significantly (r = 0.96, slope = 1.06, intercept = 0.05), the mean difference was 0.39 +/- 1.11 ml/min/100 g. Our data demonstrate that the measurement of RBBF by means of FM allows a valid determination of RBBF.     

16,16-Dimethyl prostaglandin E2 reverses focal mucosal ischemia associated with stress ulcers

Focal ischemia is postulated to contribute to gastric mucosal stress ulceration. This study evaluated directly whether or not mucosal ulceration during hemorrhagic shock is preceded by focal gastric mucosal blood flow changes, and whether or not topical Dm-PGE2 (16,16-dimethyl prostaglandin E2) affects focal gastric mucosal blood flow during hemorrhagic shock. Twelve anesthetized miniature swine had pyloric ligation and intragastric infusion of 5 ml/kg autogenous bile in 140 mM HCl. Gastric mucosal blood flow was documented by radiolabeled microspheres during normotension, initial hemorrhagic shock (50 mm Hg), and hemorrhagic shock + 50 micrograms topical Dm-PGE2. Stable shock was then maintained for 3 hr. During this time ulceration developed, shedding radiolabeled microsphere-bearing mucosa into the lumen. Intact gastric mucosa and luminal contents were collected, weighed, and gamma counted. Blood flow to intact mucosa was calculated by standard techniques. The weight of shed tissue, as well as the blood flow to shed tissue, was calculated from luminal microspheres. Results: gastric mucosal blood flow was decreased 35% with hemorrhagic shock (28.8 +/- 4.0 vs 18.7 +/- 2.7 ml/100 g/min, P less than 0.05). Blood flow to tissue which was subsequently shed averaged 6.4 +/- 3.1 ml/100 g/min at the same time period (P less than 0.05 vs surrounding tissue). Addition of Dm-PGE2 increased blood flow to shed tissue from 29 +/- 8% to 48 +/- 10% of blood flow to intact tissue (P less than 0.05). Conclusions: (1) gastric mucosal ulceration is preceded by focal decreases in gastric mucosal blood flow, and (2) topical Dm-PGE2 reverses focal mucosal ischemia during hemorrhagic shock. Dm-PGE2's ability to reverse focal ischemia suggests a mechanism for prostaglandin-mediated cytoprotection.     

Bronchial artery perfusion during cardiopulmonary bypass does not prevent ischemia of the lung in piglets: assessment of bronchial artery blood flow with fluorescent microspheres.

OBJECTIVE: Blood supply of the lungs during total cardiopulmonary bypass (CPB) is limited to flow through the bronchial arteries. This study was undertaken to assess the bronchial artery blood flow during CPB with fluorescent microspheres in a piglet model. METHODS: We subjected ten piglets (mean weight 5.0+/-0.5 kg) to 120 min of normothermic, total CPB without aortic cross-clamping, followed by 60 min of post-bypass perfusion. Fluorescent microspheres were injected into the left atrium or the aortic cannula or distal to the cannula to assess bronchial artery blood flow before, during and after CPB. The reference samples were taken from the descending aorta. We compared the different sites of injection. Tissue samples of the lungs were taken before and 60 min after CPB. RESULTS: Before CPB, total bronchial artery perfusion was 43.6+/-14.1 ml/min (4.8+/-1.3% of cardiac output) as by injection distal to the aortic cannula. These values were not different when microspheres were injected into the left atrium or the aortic cannula. There was no difference in scatter or in the amount of microspheres in the reference samples among the three injections sites. During CPB, bronchial artery perfusion was significantly decreased (4.4+/-2.4 ml/min vs. 40.0+/-5.0 ml/min before CPB) and returned to baseline values 60 min after CPB. Light microscopy of the tissue samples revealed alveolar septal thickening and a decrease in alveolar surface area after 60 min of reperfusion which was associated with a decreased capacity to oxygenate blood. CONCLUSIONS: (1) Bronchial artery blood flow can quantitatively be assessed during CPB when microspheres are injected into the ascending aorta and the reference samples are taken from the descending aorta. (2) Despite adequate perfusion pressure bronchial artery blood flow is decreased substantially during CPB. (3) The decrease in blood flow and the ultrastructural changes present at the end of CPB suggest the presence of low-flow ischemia of the lung during total CPB.     

Fluorescent microspheres reveal different regional blood flow in hyperacutely rejected nontransgenic and hDAF pig hearts

Classic features of hyperacute rejection show differential severity in the inner compared to the outer myocardium. In the present study, regional blood flow (RBF) measured by fluorescent microspheres served as a marker of the extent of hyperacute rejection. Using a working heart model, hearts of nontransgenic and hDAF transgenic pigs were perfused with human blood. Additionally, hDAF transgenic pig hearts were perfused with human blood containing GAS914 or the GPIIb/IIIa inhibitor tirofiban. Injections of fluorescent microspheres into the donor heart were performed in situ and during perfusion. Reference arterial blood samples were collected from the inferior aorta and the afterload line. Perfusion was terminated before hyperacutely rejected hearts failed to pump against the afterload column. RBF was determined in tissue samples of standardized areas of the left atrium and ventricle. Each specimen was divided into subepicardial and subendocardial tissue samples. Fluorescence intensity was measured using an automated luminescence spectrometer. At the end of perfusion with human blood, hyperacutely rejected nontransgenic pig hearts showed a higher RBF in the subendocardium. In hDAF-transgenic pig hearts perfused with unmodified human blood the subendocardial/subepicardial blood flow ratio changed in favor of the subepicardium. This ratio was not further improved by GAS914. In contrast, tirofiban was able to assimilate subepicardial and subendocardial blood flow. In conclusion, RBF of hyperacutely rejected pig hearts was inhomogeneous. Inhibition of complement activation improved the reduced subepicardial RBF, but depletion of antibodies had no positive effect. The ability of tirofiban to further increase subepicardial RBF affirms thrombosis of subepicardial veins as the defining characteristic of hyperacute rejection.     

Disturbances in renal cortical perfusion with reference to the microsphere technique

The microsphere technique for studying renal blood flow is based on injection of a small volume containing radioactively labelled microspheres into the left atrium, left ventricle or possibly the root of the aorta. In the present methodological study, superficial renal cortical blood flow and tissue oxygenation were measured in anaesthetized pigs by laser Doppler flowmetry and by oxygen surface electrode technique. Rapid and profound transient decreases in superficial renal cortical blood flow and tissue oxygenation were found after injection of small volumes of plasma and saline into the left atrium. This response was present also when solutions without microspheres were injected. The reaction was not abolished by careful adjustment of the injectate temperature. When the rapid onset of flow reduction is related to the estimated time of delivery of the bolus with microspheres, the validity of regional blood flow measurements using the microsphere technique within the superficial renal cortex must be seriously questioned.     

Anastomotic and regional blood flow following esophagogastrectomy in an opossum model.

Adenocarcinoma of the esophagus is increasing in incidence. The primary treatment is surgical resection, which is associated with considerable risk of anastomotic dehiscence and stricture. Decreased blood flow has been suggested as one of the factors contributing to these anastomotic failures. Our hypothesis was that anastomotic blood flow was decreased secondary to gastric and esophageal mobilization and would be increased by endogenous nitric oxide. Five opossums underwent esophagogastrectomy. Gastric and esophageal blood flow was measured following laparotomy, esophageal and gastric mobilization, esophagogastric resection and anastomosis, and L-arginine infusion. Radioactive microspheres were used to measure blood flow in the mucosa and muscularis of the esophagogastric anastomosis, esophagus, and stomach. Contrary to our hypothesis, blood flow in the anastomosis was maintained if not increased following esophagogastrectomy. However, the blood flow to the gastric mucosa adjacent to the anastomosis may be decreased. This suggests a possible redistribution of gastric blood flow to supply the anastomosis. If prolonged, this may contribute to poor anastomotic healing. L-Arginine infusion had no effect on blood flow at the anastomosis.     

Mucosal proctectomy using an ultrasonic scalpel

Mucosal proctectomy is becoming the operation of choice in the surgical treatment of patients with ulcerative colitis and familial polyposis coli. Dissection of the rectal mucosa and submucosa from the underlying muscularis is often difficult and, in some instances, impossible to perform. The feasibility of using an ultrasonic device to perform mucosal protectomy was studied in eight dogs. This technique produced coagulative necrosis of the mucosa and muscularis mucosa with marked edema and congestion of the submucosa. The muscularis propria remained intact. Complete destruction of the distal 7 cm of rectal mucosa required a total duration of exposure to the ultrasonic probe of at least 12 minutes. In another five dogs, total colectomy was performed above the area of the mucosal proctectomy followed by endorectal pull-through of the ileum. Follow-up studies revealed healing of the ileonal anastomosis without retraction or stricture. This technique should allow mucosal proctectomy to be performed in those patients in whom standard dissection is not possible due to fibrosis of the submucosal plane.     

Redistribution of microcirculatory blood flow within the intestinal wall during sepsis and general anesthesia

BACKGROUND: Hypoperfusion of the intestinal mucosa remains an important clinical problem during sepsis. Impairment of the autoregulation of microcirculatory blood flow in the intestinal tract has been suggested to play an important role in the development of multiple organ failure during sepsis and surgery. The authors studied microcirculatory blood flow in the gastrointestinal tract in anesthetized subjects during early septic shock. METHODS: Eighteen pigs were intravenously anesthetized and mechanically ventilated. Regional blood flow in the superior mesenteric artery was measured with ultrasound transit time flowmetry. Microcirculatory blood flow was continuously measured with a six-channel laser Doppler flowmetry system in the mucosa and the muscularis of the stomach, jejunum, and colon. Eleven pigs were assigned to the sepsis group, while seven animal served as sham controls. Sepsis was induced with fecal peritonitis, and intravenous fluids were administered after 240 min of sepsis to alter hypodynamic sepsis to hyperdynamic sepsis. RESULTS: In the control group, all monitored flow data remained stable throughout the study. During the hypodynamic phase of sepsis, cardiac output, superior mesenteric artery flow, and microcirculatory blood flow in the gastric mucosa decreased by 45%, 51%, and 40%, respectively, compared to baseline (P < 0.01 in all). Microcirculatory blood flow in the muscularis of the stomach, jejunum, and colon decreased by 55%, 64%, and 70%, respectively (P < 0.001 in all). In contrast, flow in the jejunal and colonic mucosa remained virtually unchanged. During the hyperdynamic phase of sepsis, there was a threefold increase in cardiac output and superior mesenteric artery flow. Blood flow in the gastric, jejunal, and colonic mucosa also increased (22%, 24%, and 31% above baseline, respectively). Flow in the muscularis of the stomach returned to baseline, while in the jejunum and colon, flow in the muscularis remained significantly below baseline (55% and 45%, respectively, P< 0.01). CONCLUSIONS: It appears that in early septic shock, autoregulation of microcirculatory blood flow is largely intact in the intestinal mucosa in anesthetized pigs, explaining why microcirculatory blood flow remained virtually unchanged. This may be facilitated through redistribution of flow within the intestinal wall, from the muscularis toward the mucosa.     

Small intestinal submucosa as a urethral coverage layer.

PURPOSE: Urethrocutaneous fistula is the most common complication of hypospadias surgery. Numerous techniques have been used to decrease the incidence of this complication and the use of biocompatible materials in surgery has expanded the options in difficult situations. We hypothesized that porcine small intestinal submucosa may be used as a coverage layer after urethral surgery. We evaluated the histological changes associated with small intestinal submucosa when used as a coverage layer over the urethra in a rabbit model. METHODS AND METHODS: We performed urethral surgery in 16 New Zealand White rabbits divided into 4 animals each in groups 1-sham operation with penile degloving only, 2-penile degloving and small intestinal submucosa patch placement, 3-urethrotomy without a patch and 4-urethrotomy with a small intestinal submucosa patch. The graft edges were marked with permanent suture at surgery for later identification. All rabbits were maintained for 6 weeks before sacrifice. The urethra of each animal was then serially sectioned and examined histologically. RESULTS: Histological examination of animals with an small intestinal submucosa patch revealed a foreign body tissue reaction with an infiltrate of histiocytes, giant cells and lymphocytes in the area of graft placement. There was no histological evidence of remaining small intestinal submucosa patch in any sections. The urethral mucosa healed normally in all cases in which it was disrupted. There was no evidence of acute or chronic inflammation in any group 1 or 2 nonsmall intestinal submucosa animals and none in the animals with a small intestinal submucosa graft in areas other than the former graft site. There were also no urethrocutaneous fistulas in any of the 8 rabbits that underwent urethrotomy. CONCLUSIONS: Small intestine submucosa provides an adequate coverage layer in the rabbit penis after urethrotomy. Histologically the foreign material did not alter normal healing of the urethral mucosa, although it did appear to cause an infiltration of histiocytes, giant cells and lymphocytes. Small intestinal submucosa has previously been studied as a scaffold on which tissue may be remodeled or may regenerate. Our study shows that small intestinal submucosa did not interfere with normal tissue healing in this animal model. When used as a urethral coverage layer, it appears to provide extra tissue between the urethra and skin. Small intestinal submucosa may potentially decrease the incidence of urethrocutaneous fistula after urethral surgery.     

Redistribution of Microcirculatory Blood Flow within the Intestinal Wall during Sepsis and General Anesthesia

Background: Hypoperfusion of the intestinal mucosa remains an important clinical problem during sepsis. Impairment of the autoregulation of microcirculatory blood flow in the intestinal tract has been suggested to play an important role in the development of multiple organ failure during sepsis and surgery. The authors studied microcirculatory blood flow in the gastrointestinal tract in anesthetized subjects during early septic shock.

Methods: Eighteen pigs were intravenously anesthetized and mechanically ventilated. Regional blood flow in the superior mesenteric artery was measured with ultrasound transit time flowmetry. Microcirculatory blood flow was continuously measured with a six-channel laser Doppler flowmetry system in the mucosa and the muscularis of the stomach, jejunum, and colon. Eleven pigs were assigned to the sepsis group, while seven animal served as sham controls. Sepsis was induced with fecal peritonitis, and intravenous fluids were administered after 240 min of sepsis to alter hypodynamic sepsis to hyperdynamic sepsis.

Results: In the control group, all monitored flow data remained stable throughout the study. During the hypodynamic phase of sepsis, cardiac output, superior mesenteric artery flow, and microcirculatory blood flow in the gastric mucosa decreased by 45%, 51%, and 40%, respectively, compared to baseline (P < 0.01 in all). Microcirculatory blood flow in the muscularis of the stomach, jejunum, and colon decreased by 55%, 64%, and 70%, respectively (P < 0.001 in all). In contrast, flow in the jejunal and colonic mucosa remained virtually unchanged. During the hyperdynamic phase of sepsis, there was a threefold increase in cardiac output and superior mesenteric artery flow. Blood flow in the gastric, jejunal, and colonic mucosa also increased (22%, 24%, and 31% above baseline, respectively). Flow in the muscularis of the stomach returned to baseline, while in the jejunum and colon, flow in the muscularis remained significantly below baseline (55% and 45%, respectively, P < 0.01).     

Muscularis mucosae duplication and the musculo-fibrous anomaly in endoscopic mucosal resections for barrett esophagus: implications for staging of adenocarcinoma

Endoscopic mucosal resection (EMR) is increasingly used for management of Barrett esophagus (BE)-related neoplasia. Duplication of the muscularis mucosae (MM) has been described in BE esophagectomy specimens, where it can pose difficulties with accurate staging of carcinoma. The frequency, morphologic characteristics, and effect of MM duplication in adenocarcinoma staging in EMRs have not yet been evaluated. We studied 122 EMR specimens from 100 patients from 1999 to 2006. The following histologic features were scored: depth of EMR, presence of MM duplication and its extent, prolapse changes (extension of smooth muscle into lamina propria), gland entrapment, and diagnosis (original and study/final). Carcinomas reaching the level of submucosa were classified as invasive adenocarcinoma (INV); those confined to lamina propria or MM were classified as intramucosal adenocarcinoma (IMAC). Of 122 EMRs, 11 (9%) reached mucosa only, 109 (89%) extended to submucosa, and 2 (2%) extended into muscularis propria. MM duplication was present in 67% (75 of 111 specimens that reached at least submucosa). Prolapse changes were noted in 65 (54%) cases and gland entrapment in 67 (56%). Final pathologic diagnoses were 9 (7%) no specialized Barrett mucosa, 4 (3%) BE without dysplasia, 13 (11%) low-grade dysplasia, 51 (42%) high-grade dysplasia, 33 (27%) IMAC, and 12 (10%) INV. EMRs without BE were less likely to show MM duplication (P = 0.01) and there was a trend toward less frequent prolapse change (P = 0.08) and less gland entrapment (P = 0.08) as compared with EMRs with BE. However, there were no significant differences with respect to MM duplication, prolapse change, or gland entrapment between BE with or without dysplasia, IMAC, or INV. Among 33 cases of IMAC, tumor invaded lamina propria in 10 (30%), inner or single MM in 14 (42%), space between duplicated MM in 5 (15%), and outer MM layer in 4(12%). Lymphatic invasion was seen in 2 (10%) cases in which tumor reached the space between MM layers. Overstaging of carcinomas occurred in the original reports in 8 (7%) cases due to misinterpretation of the muscular anatomy, including one case in which the deep MM was interpreted as muscularis propria. These results show that MM duplication is commonly seen in EMR specimens. It is closely associated with the presence of BE but is not affected by neoplastic progression in the Barrett epithelium. Pathologists need to be aware of this distinctive anatomy of BE for accurate staging of adenocarcinomas, particularly to avoid mistaking a thickened outer MM as muscularis propria. Level of IMAC may be a critical feature because of potential access to lymphatic spaces between duplicated MM layers, and we therefore recommend including an explicit statement about the depth of adenocarcinoma invasion rather than using only broad terms such as IMAC or INV in the diagnostic report.     

Proximal ureter of the human in reflux nephropathy and in chronic, nonreflux-induced pyelonephritis. Histomorphometric study

The total area and the proportion of lumen, epithelium, submucosa and muscularis as well as connective tissue, musculature, and edema were determined by histologic and morphometric evaluation in cross sections of 30 segments of undilatated proximal ureter. The conditions in 8 reflux ureters from children were almost identical to those in 12 reflux ureters from adults. No statistically significant increase in proliferation of connective tissue within the submucosa and muscularis could be established. The primary difference between the reflux ureters and the 10 proximal ureters in reflux-unrelated chronic pyelonephritis was extensive inflammatory edema in the submucosa and muscularis in the latter. Pathophysiologic and pathogenetic aspects are discussed.     

Microvascular changes in large flame burn wound in sheep

Advances in local wound management with early excisional therapy have decreased morbidity and mortality of massive third-degree burn patients. Although blood redistribution within burned tissue is of clinical interest, few studies have longitudinally determined the regional blood flow of various layers of the burn wound. We used a conscious ovine model in which animals were subjected to 40% third degree burn. Burned tissue was divided into the four layers (i.e. skin, panniculus carnosus, adipose tissue, and skeletal muscle), and regional blood flow was determined separately, with fluorescent microspheres, while measuring systemic hemodynamics and total burned tissue microvascular fluid flux. The subburn adipose tissue exhibited a remarkable biphasic alteration in regional blood flow, whereas the skin layer showed only decreased blood flow during the whole experimental period. The increase in blood flow to the adipose tissue seems to be related to a sustained fluid filtrate in the postresuscitation period, resulting in edema formation mainly located in the adipose tissue at the endpoint.     

Comparison of regional blood flow values measured by radioactive and fluorescent microspheres

Fluorescent microspheres (FM) have become an attractive alternative to radioactive microspheres (RM) for the measurement of regional blood flow (RBF). The aim of the present study was to investigate the comparability of both methods by measuring RBF with FM and RM. Eight anaesthetised pigs received simultaneous, left atrial injections of FM and RM with a diameter of 15 microm at six different time points. Blood reference samples were collected from the descending aorta. RBF was determined in tissue samples of the myocardium, spleen and kidneys of all 8 animals. After radioactivity of the tissue samples was determined, the samples were processed automatically for measuring fluorescence using a recently developed filter device (SPU). RBF was calculated with both the isotope and spectrometric data of both methods for each sample resulting in a total of 10,512 blood flow values. The comparison of the RBF values yielded high linear correlation (mean r(2) = 0.95 +/- 0.03 to 0.97 +/- 0.02) and excellent agreement (bias 5.4-6.7%, precision 9.9- 16.5%) of both methods. Our results indicate the validity of MS and of the automated tissue processing technique by means of the SPU.     

Ultrasonic fragmentation. A new technique for mucosal proctectomy

We report a new technique for mucosal proctectomy that does not require manual separation of the mucosa and submucosa from the underlying muscularis. Mucosal proctectomy using ultrasonic fragmentation of the rectal mucosa was performed in four patients. Three had severe ulcerative colitis, and one patient had radiation proctitis with a rectal stricture. In all cases an endorectal pullthrough with anastomosis to the area of the dentate line was performed. Healing after ultrasonic mucosal proctectomy occurred without infection or retraction. Ultrasonic fragmentation offers an alternative to the standard technique of mucosal proctectomy. This new method is useful in those patients in whom separation of the rectal mucosal layer is difficult to perform.     

Early Regenerative Response in the Intrathoracic Porcine Esophagus—The Impact of the Inflammation

In order to improve the treatment of children born with long‐gap esophageal atresia, a porcine model was developed for studying esophageal regrowth using a bridging graft composed of a silicone stented Biodesign mesh. The aim of the study was to investigate how leakage and contact between the native muscle and Biodesign mesh affected the early healing response. Resection of 3 cm of intrathoracic esophagus was performed in 10 newly weaned piglets. They were fed through a gastrostomy 8–10 days prior to sacrifice. In order to achieve nonleaking anastomoses, the silicone stent and suturing technique had to be adjusted between the first four and second six piglets. The technical adjustment decreased leakage. A nonleaking anastomosis could not be achieved when the native muscle layers were sewn less central on the bridging graft compared with the mucosa. If there was leakage, the inflammatory response increased, with islets of perivascular T‐lymphocytes and infiltration of macrophages in the native muscle layers. In the bridging area, new vessels were seen in the submucosa in 9 of 10 piglets between 4 and 10 days after surgery. Smooth muscle cells also appeared to move from the cut muscle edges of both the muscularis mucosa and the lamina muscularis and were seen as a layer of several cells under newly formed mucosa. Double staining of the basal membrane of the ingrowing vessels and the pericytes showed that the basal membrane was thinner over some of the pericytes, but there was no accumulation of immature‐looking cells in the submucosa of the bridging area. In this porcine model, where esophageal regrowth was studied by using a bridging graft composed of a silicone stented Biodesign mesh, we can conclude that leakage increased the inflammatory response in early healing. Ingrowth of new vessels was seen in the bridging area and movement of smooth muscle cells was found under newly formed mucosa.     

Microspheres accurately predict regional bone blood flow

Even though the microsphere method frequently is used to determinate bone blood flow, validation of this technique for bone blood flow measurement is incomplete. The method is based on the principle that injected microspheres are distributed with the arterial blood and trapped in the capillaries because of their diameter (15 microm). The number of spheres lodged in an organ is proportional to its blood flow. The number of radioactive or fluorescent microspheres in a specific organ is determined indirectly by measuring radioactivity or fluorescence intensity in the organ. In this study the reliability and precision of the microsphere method for determining bone blood flow was established using radioactive and fluorescent microspheres. Six female, anesthetized New Zealand rabbits received left ventricular injections of pairs of fluorescent and/or radioactive microspheres. The humerus, femur, and tibia were dissected in a standardized manner and blood flow was determined in each sample. Comparison of relative blood flow values showed an excellent correlation between radioactive and fluorescent microspheres. The percentage difference and variation between two simultaneously injected sets of microspheres was minimal for radioactive microspheres (0.8% +/- 9.6%) and for fluorescent microspheres (0.2% +/- 11.4%). Regional bone blood flow in different regions of the femur, tibia, or humerus ranged from 2.2-28.1 mL/minute/100 g, but there was no significant difference between right and left bone samples of the same region after repeated measurement. Radioactive and fluorescent microspheres allow precise determination of regional bone blood flow.