The use of total circulatory arrest in the surgery of giant hemangioma and Klippel-Trenaunay syndrome in neonates.

Two neonates required deep hypothermia and circulatory arrest to provide a central control of blood loss for the resection of giant cavernous hemangiomas. Both infants were placed on cardiopulmonary bypass, cooled to 16 degrees, and exsanguinated before resection of these peripheral lesions. The surgery was done as a lifesaving measure in both instances because both infants were suffering from high-output cardiac failure. In both cases, the small total blood volumes were critical in excision of these hypervascular tumors. Use of the techniques described allowed for the surgery to be performed in a bloodless field over a short period (one hour), thus preventing massive blood loss. Both patients are living with no neurologic or developmental deficits more than five years after the operation.

Evidence that polygalacturonic acid may not be a major source of carbon and energy for some colonic Bacteroides species.

Five Bacteroides species that are found in the human colon can utilize polygalacturonic acid (PGA) when they are grown in laboratory media: Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Bacteroides fragilis subsp. a, and Bacteroides sp. strain 3452A (an unnamed DNA-DNA homology group). PGA-degrading enzymes from B. thetaiotaomicron have been isolated and characterized previously. To determine whether a PGA lyase activity in human feces could be attributed to any of these species, we first determined the properties of PGA lyases from the other four Bacteroides species. PGA lyases from all the Bacteroides species were soluble, cell associated, and inducible by PGA. All had similar pH optima (8.4 to 8.8) and similar molecular weights (50,000). All activities were enhanced by calcium. The PGA lyases from the five species differed with respect to isoelectric point: B. thetaiotaomicron (pI 7.5), B. vulgatus (pI 7.7), B. ovatus (pI 5.8, 7.2), B. fragilis subsp. a (pI 6.1), and Bacteroides sp. strain 3452A (pI 7.7). The PGA lyase activity in human feces resembled those of the Bacteroides PGA lyases in that it had a pH optimum of 8.4 to 8.8 and was enhanced by calcium. However, it differed from the Bacteroides PGA lyases both with respect to isoelectric point (pI 4.2 to 4.4) and molecular weight (100,000). On the basis of these findings, it appears that the PGA lyase activity in human feces is not produced by any of the Bacteroides species surveyed in this survey. Moreover, there was no detectable PGA lyase activity in feces that had the same properties as the Bacteroides enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Location and characteristics of enzymes involved in the breakdown of polygalacturonic acid by Bacteroides thetaiotaomicron.

When Bacteroides thetaiotaomicron is grown in medium which contains polygalacturonic acid (PGA) as the sole carbon source, two different polygalacturonases are produced: a PGA lyase (EC 4.2.2.2) and a PGA hydrolase (EC 3.2.1.15). Both enzymes are cell associated. The PGA hydrolase appears to be an inner membrane protein. The PGA lyase is a soluble protein that associates with membranes under certain conditions. The PGA lyase was purified to apparent homogeneity. It has a molecular weight (from sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of 74,000, a pH optimum of 8.7, a pI of 7.5, and a Km for PGA of 40 to 70 micrograms/ml. It requires calcium for maximal activity. The main product of this enzyme appears to be a disaccharide that contains a delta 4,5-unsaturated galacturonic acid residue. The PGA hydrolase can be solubilized from membranes with 2% Triton X-100 and has been partially purified. It has a pH optimum of 5.4 to 5.5, a pI of 4.7 to 4.9, and a Km for PGA of 350 to 400 micrograms/ml. The main product of this enzyme appears to be galacturonic acid. The specific activities of both PGA hydrolase and PGA lyase increase at the same rate when bacteria are exposed to PGA. The two enzymes therefore appear to be similarly regulated.