Development and assessment of morphologic criteria for diagnosing gastric cancer using confocal endomicroscopy: an ex vivo and in vivo study

BACKGROUND AND STUDY AIMS

The Confocal Endomicroscopy System (Optiscan Pty Ltd. and Pentax Corp.) is a newly developed imaging tool that uses laser light and optical technology to visualize living tissue at the cellular level. Digital images of cells magnified 1000-fold appear in real time on a computer screen, which enables immediate detection of changes in cellular structure without the need for a biopsy. The aim of this study was to assess the features of the cellular architecture of cancerous tissue that can be used in the differential diagnosis of cancerous tissue and normal mucosa using this system's image-processing software.

PATIENTS AND METHODS

A total of 27 gastric cancers were examined ex vivo using confocal endomicroscopy. A fluorescent contrast agent, acriflavine, was applied topically to normal and to cancerous mucosa. In vivo imaging of the gastric mucosa after intravenous injection of fluorescein sodium was also performed in nine patients with gastritis or gastric cancer.

RESULTS

The nuclear area in the ex vivo specimens was calculated using Scion Image software. The mean nuclear area of cancer cells was found to be significantly larger than that of normal cells in 18/27 gastric cancers (67 %). The mean nuclear area of the cancers tended to be larger than that of normal mucosa, especially in cases of differentiated adenocarcinoma. In more than half the cases, it was possible to diagnose malignancy automatically using confocal endomicroscopy and image-processing software without the need for biopsy and pathological examination. In vivo imaging of cancerous lesions showed irregularity in cellularity and vascularity.

CONCLUSION

The ability of this imaging device to differentiate between normal tissue and cancerous tissues gives it potential value as a new screening tool for early detection of malignancy.

Study on adsorption mechanism of proteins onto synthetic calcium hydroxyapatites through ionic concentration measurements

To clarify the adsorption mechanism of proteins onto calcium hydroxyapatite (Hap), the kinetic studies of dissolution and ion-exchange properties of synthetic Hap particles in the absence and presence of proteins were examined at 15 degrees C. In the absence of proteins, Hap particles slightly dissolved to give low amounts of calcium ([Ca(2+)] = 0.09-0.14 micromol m(-2)) and phosphate [PO(4) (3-)] = 0.01-0.08 micromol m(-2)) ions in KCl, CaCl(2), BaCl(2) and AlCl(3) solutions. The [Ca(2+)] increased with increase in the Ca/P ratio of Hap, while the [PO(4) (3-)] decreased. The[ Ca(2+)] and [ PO(4) (3-)] were independent of the ionic strength. Ba(2+) and AI(3+) ions were completely ion-exchanged with calcium ions in Hap lattice within 2 hr. The solution pH was increased by 1.1-1.8 after the dissolution of OH(-) ions on the Hap surface. In the presence of bovine serum albumin (BSA), the Hap particles dissolved slightly faster than the systems without protein. This fact was explained by a complexation of dissolved ions to functional groups of BSA. The adsorption of BSA induced a reduction of [Ca(2+)] and [ PO(4) (3-)] in the aqueous medium and minima appeared on [Ca(2+)] and [PO(4) (3-)] profiles before the BSA adsorption reached a saturation. This result suggests that the adsorption of BSA onto Hap is governed by [Ca(2+)] ions complexing to BSA molecules (binding effect) together with the operation of [Ca(2+)] ions exposing on the Hap surfaces by dissolution of OH(-) ions, so-called "C-sites". The addition of BaCl(2) and AlCl(3 )steeply increased the amounts of adsorbed BSA (n(BSA)) at the initial adsorption step by the strong binding effect of these di- and tri-valent cations between BSA and Hap. However, after eliminating these cations from the Hap surface by the ion-exchange reaction, the binding effects disappeared and n(BSA) decreased. Since the number of functional groups is small, the binding effect of the counter ions was only slightly detected for the systems with di- and trivalent ions on the adsorption systems of lysozyme (LSZ).

Effects of endotoxin on intestinal hemodynamics, glutamine metabolism, and function

The purpose of this study was to investigate the intestinal hemodynamics and gut glutamine metabolism during endotoxemia, and their correlation with altered intestinal absorptive capacity and permeability. Seventeen Sprague-Dawley rats were used in the study. The endotoxin group (ENDO) received endotoxin (10 mg/kg intraperitoneally, n = 9), while the control group (CONT, n = 8) received saline injection. Twelve hours later, D-xylose (0.5 g/kg) and fluorescein isothiocyanate-dextran (FITC-dextran, 750 mg/kg) were given by oral gavage. One hour later abdominal aortic (AA) blood flow, superior mesenteric venous (SMV) flow, mean arterial pressure (MAP), central venous pressure (CVP), and SMV pressure (SMVP) were also measured. The MAP, AA, and SMV blood flow decreased (P < 0.05), while the CVP and SMVP increased (P < 0.05) in the ENDO group as compared with the CONT group. The ENDO group showed significant decreases for both intestinal glutaminase activity and net intestinal glutamine uptake (P < 0.05). The D-xylose concentration in SMV decreased significantly (P < 0.05) in the ENDO group as compared with the CONT group. However, the plasma FITC-dextran concentration showed no significant difference between the groups. Endotoxin produced a hypodynamic effect in rats 12 h after intraperitoneal administration in association with both a decreased intestinal glutamine metabolism and an absorptive capacity.

Influence of glutamine-supplemented parenteral nutrition on intestinal amino acid metabolism in rats after small bowel resection

Glutamine (Gln)-supplemented total parenteral nutrition (TPN) has been shown to improve mucosal adaptation after massive small bowel resection (SBR); however, its influences on intestinal amino acid metabolism remain unknown. In this study, intestinal amino acid flux, circulating plasma aminogram, mucosal glutaminase activity and protein, and DNA content were measured 7 days after massive SBR in rats receiving either standard (Std) or Gln-supplemented TPN. Sham-operated rats and rats fed chow after enterectomy served as controls. The uptake of Gln and the release of citrulline (Cit) by the remaining intestine was significantly decreased, with reduced mucosal glutaminase activity after SBR in the Chow and Std-TPN groups. Glutamine supplementation resulted in significantly increased gut Gln uptake compared with Std-TPN (P < 0.01). Mucosal glutaminase activity, mucosal protein, and DNA content was also increased by Gln; however, the gut release of Cit remained unchanged (P > 0.05). The subsequent decrease in circulating arginine (Arg) in the Gln-TPN group compared with the Std-TPN group (P < 0.05) was attributed to an insufficient exogenous supply. These findings show that Gln-supplemented TPN improves mucosal growth and gut Gln uptake after SBR. However, the intestinal production of Cit, which remained low in both TPN groups, may lead to an insufficiency of endogenous Arg synthesis. Thus, both Gln and Arg may be essential amino acids after SBR.

Quantification of intestinal blood flow by ultrasonic transit time flowmetry in fed and endotoxaemic rats

OBJECTIVE

To compare the dye dilution method with ultrasonic transit time flowmetry (UTTF) for quantifying intestinal blood flow in the same experimental animals.

DESIGN

Open experimental study.

SETTING

University hospital, Osaka, Japan.

MATERIAL

11 (experiment 1) and 25 (experiment 2) adult male Sprague-Dawley rats.

INTERVENTIONS

In experiment 1, the rats were fasted overnight. In experiment 2, endotoxin, Escherichia coli lipopolysaccharide (endotoxin) or saline (sham) was injected intraperitoneally.

MAIN OUTCOME MEASURES

Superior mesenteric venous and abdominal aortic blood flow.

RESULTS

Experiment 1: intestinal blood flow measured by UTTF was significantly decreased by 17% (p < 0.05) and 56% (p < 0.05) after 30 minutes infusion through the tertiary branch of the mesenteric vein and during simultaneous drawing of blood samples from both the carotid artery and the superior mesenteric vein over a 1.5 minute period, respectively. The intestinal blood flow measurements obtained by UTTF at different intervals before simultaneous drawing of blood from the carotid artery and the superior mesenteric vein differed significantly (p < 0.05) from those obtained by the dye dilution method. Experiment 2: intestinal blood flow was also decreased by 21%-34% (p < 0.05) during similar simultaneous drawing of blood. Aortic blood flow in the endotoxin group was reduced by 66% (p < 0.05) compared with fed animals and 63% (p < 0.05) compared with sham animals. Simultaneously, intestinal blood flow in the endotoxin group was also reduced by 57% (p < 0.05) compared with fed or 48% (p < 0.05) compared with sham treated animals.

CONCLUSION

Real intestinal blood flow might not be measured by the procedure of simultaneously drawing blood from the carotid artery and the superior mesenteric vein in rats as is usually done in the dye dilution method. Intraperitoneal endotoxin reduced aortic as well as intestinal blood flow. We propose that UTTF is an alternative method for quantifying intestinal blood flow in fed and endotoxaemic animals.

Alanyl-glutamine dipeptide-supplemented parenteral nutrition improves intestinal metabolism and prevents increased permeability in rats

OBJECTIVE

The authors determined the effects of alanyl-glutamine-supplemented total parenteral nutrition (TPN) on mucosal metabolism, integrity, and permeability of the small intestine in rats.

METHODS

Male Sprague-Dawley rats were randomized to receive TPN supplemented with a conventional amino acids mixture (STD group) or the same solution supplemented with alanyl-glutamine; both solutions were isocaloric and isonitrogenous. On the seventh day of TPN, D-xylose and fluorescein isothiocyanate (FITC)-dextran were administered orally. One hour later, superior mesenteric vein (SMV) D-xylose and plasma FITC-dextran concentration were measured. Intestinal blood flow and calculated intestinal substrates flux were measured with ultrasonic transit time flowmetery.

RESULTS

Plasma FITC-dextran increased significantly in the STD group. Intestinal blood flow and SMV D-xylose concentration did not differ between the groups. Mucosa weight, villus height, mucosal wall thickness, mucosal protein, and DNA and RNA content in jejunal mucosa were significantly increased in the alanyl-glutamine group. Jejunal mucosal glutaminase activity and net intestinal uptake of glutamine (glutamine flux) were significantly higher in the alanyl-glutamine group as compared with the STD group.

CONCLUSION

Addition of alanyl-glutamine dipeptide to the TPN solution improves intestinal glutamine metabolism and prevents mucosal atrophy and deterioration of permeability.