The healing and tensile strength of the gastroplasty staple line. An experimental study

Inverted and everted staple lines, with and without division of the anterior gastric wall, were performed in 15 mongrel dogs to simulate reduction gastroplasty staple line. There were no significant differences in tensile strength and healing between staple lines at different postoperative periods. The tensile strength of the inverted staple line seemed to be stronger due to breakage of the adjacent gastric tissue. However, the tensile strength of the everted stapling without division of the gastric wall, which is used clinically, was almost equal to that of normal gastric tissue. In addition, there was satisfactory healing 4 weeks postoperatively in the everted stapling without dividing the gastric wall. These results suggest that the everted staple line without division of stomach is not inherently weaker to any significant extent than if the gastric wall was divided or inverted. The reported failure rate of this procedure may be due to other factors.

Intestinal valve formation with a simple invagination technique

In 17 fully conditioned mongrel dogs, the small intestine approximately 50 cm proximal to the ileocecal valve was divided. Three centimeters of the proximal bowel was then inserted into the distal bowel and anastomosis was performed using interrupted 3-0 Dexon sutures in the seromuscular layer of the proximal end and through the entire thickness of the distal end. Two to four dogs were then sacrificed 2, 4, 6, 8, and 10 weeks postoperatively. Two dogs died 3 and 4 weeks postoperatively due to mechanical obstruction just proximal to the anastomosis by hair bezoar, and 15 survived without complications. Retrograde contrast radiologic examination of all segments showed no reflux. Microscopically, the serosal surface of the invaginated segment was found to be gradually covered with mucosa, and the whole segment formed a valvelike structure within 10 weeks time.

Electron microscopy of bacteriophage phi 6 nucleocapsid: three-dimensional image analysis

Electron micrographs of bacteriophage phi 6 nucleocapsids, negatively stained by neutralized phosphotungstate and tilted in a goniometer specimen cartridge, proved that the three distinct morphologies seen in the electron microscope are merely three different aspects of a single nucleocapsid structure and strongly suggested that this structure is dodecahedral.

Complement activation by heat-killed human kidney cells: formation, activity, and stabilization of cell-bound C3 convertases

Heat-killed kidney cells (HKKC) incubated with serum or purified C3 and factors B and D stain intensely for C3 by immunofluorescence. Binding of complement (C) did not occur if ethylenediaminetetraacetic acid (EDTA) was added to the C source or if factor B or D was omitted from the mixture of alternative pathway components. When the C-treated cells were washed, then incubated in purified C3 containing 10 mM EDTA, C3 conversion ensued, confirming the presence of a cell-bound C3 convertase. C3-reactive cells were not generated if EDTA was present during formation of the convertase. The addition of C3 nephritic factor (C3NeF) during formation of the C3 convertase from alternative pathway components greatly enhanced subsequent C3 cleavage, presumably by stabilizing labile C3bBb sites; however, binding of C3NeF did not appear to extend the half-life of the convertase, which was 35 min at 37 degrees C in each case. In contrast, little or no effect on C3 conversion could be detected after the addition of equivalent C3NeF to serum and HKKC. Thus, C activation by HKKC involves formation and activity of a cell-bound C3 convertase, which under certain circumstances can be stabilized by C3NeF.

Complement activation by heat-killed human kidney cells: formation, activity, and stabilization of cell-bound C3 convertases

Heat-killed kidney cells (HKKC) incubated with serum or purified C3 and factors B and D stain intensely for C3 by immunofluorescence. Binding of complement (C) did not occur if ethylenediaminetetraacetic acid (EDTA) was added to the C source or if factor B or D was omitted from the mixture of alternative pathway components. When the C-treated cells were washed, then incubated in purified C3 containing 10 mM EDTA, C3 conversion ensued, confirming the presence of a cell-bound C3 convertase. C3-reactive cells were not generated if EDTA was present during formation of the convertase. The addition of C3 nephritic factor (C3NeF) during formation of the C3 convertase from alternative pathway components greatly enhanced subsequent C3 cleavage, presumably by stabilizing labile C3bBb sites; however, binding of C3NeF did not appear to extend the half-life of the convertase, which was 35 min at 37 degrees C in each case. In contrast, little or no effect on C3 conversion could be detected after the addition of equivalent C3NeF to serum and HKKC. Thus, C activation by HKKC involves formation and activity of a cell-bound C3 convertase, which under certain circumstances can be stabilized by C3NeF.

Experimental study of singly placed staples for an everted intestinal anastomosis

This study was undertaken to confirm the technical feasibility and efficacy of an intestinal anastomosis created with singly placed staples in dogs. In 12 fully conditioned dogs, two end-to-end small bowel anastomoses were performed in an everted manner. In each dog, one anastomosis was performed with singly placed staples utilizing the Auto Suture 4.8 mm disposable skin stapler, and the other anastomosis was performed with a manual technique using 3-0 Dexon interrupted suture. Operation time was measured for each anastomosis. Dogs were sacrificed 2, 4, and 8 weeks postoperatively. Each anastomosis was examined grossly and microscopically, and its tensile strength was measured. All dogs survived without complications. Gross and microscopic examinations showed satisfactory healing of both types of anastomoses at different postoperative intervals. The stapled anastomosis required significantly shorter time (p less than 0.01), and had significantly greater tensile strength (p less than 0.05) when compared with manual anastomosis.

Change in membrane lipid fluidity induced by phospholipase A activation: a mechanism of endotoxic shock

The effects of endotoxin administration on the fluidity of dog liver plasma membranes and their relationship with changes in phospholipase A2 activity were studied. Endotoxin administration decreased the fluidity of liver plasma membranes and this decrease was reversible by phosphatidylcholine. The endotoxin-induced decrease in membrane fluidity could be mimicked by digesting control liver membranes with exogenous phospholipase A2. Endotoxin administration also increased the endogenous phospholipase A2 activity. Endotoxin in vitro had no phospholipase A2-like activity but it activated the hydrolytic activity of exogenous phospholipase A2. Based on these data, it is concluded that endotoxin administration decreased the fluidity of canine liver plasma membranes by acting through activation of phospholipase A2. The decrease in membrane lipid fluidity induced by endotoxin administration may play a significant role in the development of the pathophysiology of endotoxic shock at the cellular level.

Incoherent method for rotation-invariant recognition

An optodigital hybrid system using an incoherent circular correlator that has features suitable for space and industrial applications is introduced. The incoherent circular correlator uses a fiber-optics sampler and carries out the correlations in white light. The trade offs involved for efficient detection of objects are discussed. The system has been built, and experimental results on a real air photograph are presented.

Digital multiple correlation for pattern recognition

A method of digital multiple correlation for rotation-invariant recognition has been developed. It is also a computer simulation of an incoherent optodigital hybrid system previously introduced. Speed and flexibility of the digital system are investigated.

Hydrolysis of 4-methylumbelliferyl N-acetyl-chitooligosaccharides catalyzed by human lysozyme

Binding of N-acetyl-chitotetraose, 4-methylumbelliferyl chitotrioside ((GlcNAc)3-MeU), and 4-methylumbelliferyl chitotetraoside ((GlcNAc)4-MeU) to human lysozyme [EC 3.2.1.17] was studied by fluorescence measurement. Hydrolysis of (GlcNAc)3-MeU and (GlcNAc)4-MeU catalyzed by human lysozyme was studied by measuring the release of 4-methylumbelliferone fluorimetrically and the kinetic constants were determined in the pH range of 2 to 8 at 0.1 ionic strength and 42 degrees C. On the basis of binding and kinetic data, it was shown that (GlcNAc)3-MeU binds mainly to subsites A to D with the terminal MeU group bound to subsite D (nonproductive binding) and that (GlcNAc)4-MeU binds to subsites A to E (productive binding) and subsites A to D with the nonreducing sugar residue extending beyond subsite A (nonproductive binding). The pH dependences of the kinetic constants for hydrolysis of (GlcNAc)3-MeU and (GlcNAc)4-MeU were analyzed assuming that nonproductive binding occurs competitively, that an ionizable group in addition to the catalytic groups (Asp 52 and Glu 35) participates in the catalysis, and that the molecular species with ionized Asp 52 and protonated Glu 35 is active. Analyses of the kinetic constants for (GlcNAc)3-MeU and (GlcNAc)4-MeU both gave the same pK values of the catalytic groups (pK52 = 3.6(3) and pK35 = 6.6(8) at 0.1 ionic strength and 42 degrees C). These pK values were very close to the values determined previously by spectroscopic methods in our laboratory (Kuramitsu et al. (1974) J. Biochem. 76, 671-683; (1978) ibid. 83, 159-170; (1980) ibid. 87, 771-778).

Hydrolysis of 4-methylumbelliferyl N-acetyl-chitotetraoside catalyzed by hen lysozyme

Binding of 4-methylumbelliferyl chitotetraoside ((GlcNAc)4-MeU) to hen lysozyme [EC 3.2.1.17] was studied by measuring changes in fluorescence at 375 nm. Hydrolysis of (GlcNAc)4-MeU catalyzed by lysozyme was studied by measuring the release of 4-methylumbelliferone from (GlcNAc)4-MeU fluorimetrically, and the kinetic constants were determined in the pH range of 2 to 8 at 0.1 ionic strength and 42 degrees C. The binding and kinetic data showed that (GlcNAc)4-MeU binds to subsites A to E (productive binding) and subsites A to D with the nonreducing sugar residue extending beyond subsite A (nonproductive binding). The fraction of the productive complex was 0.77 at pH 8.5. The pH dependence of the kinetic constants was analyzed assuming that the molecular species with ionized Asp 52 and protonated Glu 35 is active and Asp 101 participates in the binding (Phillips (1966) Sci. Am. 215, 78-90; Blake et al. (1967) Proc. Roy. Soc. B167, 378-388), and the pK values of these groups were determined. The pK values of Asp 52, Glu 35, and Asp 101 were 3.60, 6.20, and 4.20, respectively, for free lysozyme, 3.40, 6.55, and 3.40, respectively, for the productive complex, and 3.95, 6.55, and 3.30, respectively, for the nonproductive complex. The pK values for free lysozyme were in excellent agreement with those obtained by analysis of the kinetic constants for (GlcNAc)3-MeU (Yang & Hamaguchi (1980) J. Biochem. 87, 1003-1014). The free energy of activation was 24 kcal mol-1 at pH 5.2. Comparison with the corresponding value obtained for hydrolysis of (GlcNAc)6 (Banerjee et all (1975) J. Biol. Chem. 250, 4355-4367) suggests that the interactions of GlcNAc residues with subsites E and F in the transition state are important in lysozyme catalysis. Hydrolysis of (GlcNAc)2-MeU catalyzed by lysozyme was also studied, and the Kcat/Km values for (GlcNAc)2-MeU, (GlcNAc)3-MeU, and (GlcNAc)4-MeU were compared.