Biliary tract complications of side-to-side without T tube versus end-to-end with or without T tube choledochocholedochostomy in liver transplant recipients.

BACKGROUND: Biliary anastomotic complications remain a major cause of morbidity in liver transplant recipients, ranging between 10% and 50% in large clinical series. An end-to-end choledochocholedochostomy with or without T tube (CDCD EE with T tube and CDCD EE w/o T tube) and a Roux-en Y choledochojejunostomy have been standard methods for biliary drainage. METHODS: The objectives of this retrospective study were to: (1) evaluate the incidence of biliary tract complications using a new method of side-to-side choledochocholedochostomy without T tube (CDCD SS w/o T tube) and (2) compare the results of CDCD SS w/o T tube with those of CDCD EE with T tube and CDCD EE w/o T tube. From September 1991 through June 1996, 279 orthotopic liver transplants were performed in 268 patients and followed through December 1996 (minimum of 6 months' follow-up). A total of 227 CDCD anastomoses in 220 patients were studied (7 retransplants > 30 days): CDCD EE with T tube (n=124), CDCD EE w/o T tube (n=44), and CDCD SS w/o T tube (n=59). RESULTS: Sixty-nine biliary complications were observed in 220 patients (30%). Anastomotic and/or T-tube leaks were seen in 43 patients (19%), and anastomotic strictures were found in 26 patients (12%). Forty patients (18%) required percutaneous or endoscopic stent placement (6%) or surgical interventions (12%). CDCD EE with T tube had the highest incidence of biliary leak requiring rehospitalization but the lowest anastomotic stricture and intervention rate and the lowest 6-month mortality rate. CONCLUSIONS: CDCD EE with T tube was superior to CDCD EE or CDCD SS w/o T tube despite the increased number of rehospitalizations. CDCD SS w/o T tube did not offer significant advantages over conventional biliary anastomotic techniques.

Protein-protein interactions involving T4 phage-coded deoxycytidylate deaminase and thymidylate synthase.

The enzymes deoxycytidylate deaminase (EC) and thymidylate synthase (EC) are functionally associated with one another, since they catalyze sequential reactions. In T4 coliphage infection the two enzymes are found in dNTP synthetase, a multienzyme complex for deoxyribonucleotide biosynthesis. Protein-protein interactions involving the phage-coded forms of these two enzymes have been explored in three experiments that use the respective purified protein as an affinity ligand. First, an extract of radiolabeled T4 proteins was passed through a column of immobilized enzyme (either dTMP synthase or dCMP deaminase), and the specifically bound proteins were identified. Second, two mutant form of dCMP deaminase (H90N and H94N), altered in presumed zinc-binding sites, were analyzed similarly, with the results suggesting that some, but not all, interactions require normal structure near the catalytic site. Third, affinity chromatography using either enzyme as the immobilized ligand, revealed interactions between the two purified enzymes in the absence of other proteins. In these experiments we noted a significant effect of dCTP, an allosteric modifier of dCMP deaminase, upon the interactions.

T4 phage gene 32 protein as a candidate organizing factor for the deoxyribonucleoside triphosphate synthetase complex.

After T4 bacteriophage infection of Escherichia coli, the enzymes of deoxyribonucleoside triphosphate biosynthesis form a multienzyme complex that we call T4 deoxyribonucleoside triphosphate (dNTP) synthetase. At least eight phage-coded enzymes and two enzymes of host origin are found in this 1.5-mDa complex. The complex may shuttle dNTPs to DNA replication sites, because replication draws from small pools, which are probably highly localized. Several specific protein-protein contacts within the complex are described in this paper. We have studied protein-protein interactions in the complex by immobilizing individual enzymes and identifying radiolabeled T4 proteins that are retained by columns of these respective affinity ligands. Elsewhere we have described interactions involving three T4 enzymes found in the complex. In this paper we describe similar analysis of five more proteins: dihydrofolate reductase, dCTPase-dUTPase, deoxyribonucleoside monophosphokinase, ribonucleotide reductase, and E. coli nucleoside diphosphokinase,. All eight proteins analyzed to date retain single-strand DNA-binding protein (gp32), the product of T4 gene 32. At least one T4 protein, thymidylate synthase, binds directly to gp32, as shown by affinity chromatographic analysis of the two purified proteins. Among its several roles, gp32 stabilizes single-strand template DNA ahead of a replicating DNA polymerase. Our data suggest a model in which dNTP synthetase complexes, probably more than one per growing DNA chain, are drawn to replication forks via their affinity for gp32 and hence are localized so as to produce dNTPs at their sites of utilization, immediately ahead of growing DNA 3' termini.

An immunoblot assay reveals that bacteriophage T4 thymidylate synthase and dihydrofolate reductase are not virion proteins.

Numerous reports describe the phage T4 enzymes thymidylate synthase and dihydrofolate reductase as structural components of the baseplate. However, Y. Wang and C. K. Mathews (J. Virol. 63:4736-4743, 1989) reported that antisera against the respective recombinant enzymes failed to neutralize phage infectivity, in contrast to previous results. Moreover, a deletion mutant lacking the genes for these two enzymes adsorbed normally to host cells. Since these findings tended to undermine the idea of the two enzymes as structural proteins, we developed a quantitative immunoblot assay to resolve the issue directly. Our results show that both enzymes are present only as minor contaminants (< 0.05 copy per phage) and as such cannot be bona fide structural proteins.

Initial two-year results of the Oregon Liver Transplantation Program.

During the first 24 months of the Oregon Liver Transplantation Program, which began in October 1988, 94 patients were formally evaluated and 47 adults underwent 54 liver transplantations. Thirty-four percent of patients were veterans. The recipient operation lasted a mean of 7.4 hours (range: 4 to 16 hours). Veno-venous bypass was used routinely at first but selectively later (7 of the last 26 cases), resulting in reduced operating time. Hepatic artery reconstruction was end-to-end anastomosis in 52 cases and iliac conduit in 2. No arterial thrombosis occurred. Biliary reconstruction was choledochocholedochostomy in 83% and choledochojejunostomy in 17%. Biliary complications occurred in 28%. Operative mortality was 2%, and 1-year actual survival was 80%. Patients with hepatitis B fared worse, with four of six dying at a mean of 7.6 months. Overall, the median hospital stay was 30 days. Patients surviving more than 3 months had a mean Karnofsky score of 82%. No significant difference in outcome was noted in patients receiving prophylactic OKT3 monoclonal antibody (used in 45%) versus conventional immunosuppressive therapy. Overall, allograft rejection occurred in 55% of patients. Retransplantation was required in seven patients, three for primary graft nonfunction, two for uncontrolled rejection during induction therapy with OKT3, and two for graft failure secondary to recurrent hepatitis B.

Characterization of limestones and their effects in vitro and in vivo in dairy cattle.

Capacities of limestones of differing particle size to neutralize acid in vitro and to modify pH and utilization of feedstuffs in vivo were compared. Acid neutralization during pH-stat titrations was faster for fine than for coarse limestone, and mixed microbial cultures were more resistant to pH change when they contained fine calcium carbonate. Diets containing 25:75 corn silage to concentrates and .95% calcium from either coarse or fine limestone were fed to rumen-fistulated heifers. Total ruminal volatile fatty acid concentrations were higher for the fine limestone treatment. Ruminal volumes, dry matter disappearance, and ruminal fluid pH and dilution rate did not differ between fine and coarse limestone treatments. Ruminal fluid volume, osmolality, ratios of acetate to propionate, and concentrations of total volatile fatty acids were unaffected in rumen-fistulated Holstein cows fed 60:40 corn silage to concentrates and either .5% calcium (control) or 1.0% calcium from either coarse or fine limestone. Ruminal pH increased .07 to .10 units with limestone supplementation. Ruminal fluid dilution and particulate turnover rates were slower for the coarse limestone than the control treatment. Differences between coarse and fine limestones in vitro were observed under some conditions in vivo, but they were not consistent.

Neutralization of acid in the rumen by magnesium oxide and magnesium carbonate.

Two reagent and two feed grade magnesium oxides and reagent grade magnesium carbonate, sodium bicarbonate, and calcium carbonate were evaluated to ascertain their ability to neutralize acid in the rumen. Rumen fluid pH was increased in vitro, compared to the control, by antacid compounds, and their increased ranked: calcium carbonate less than feed grade magnesium oxide A less than light magnesium oxide and feed grade magnesium oxide B less than heavy magnesium oxide less than magnesium carbonate less than sodium bicarbonate. Titrations at constant pH's ranging from 3.0 to 7.5 indicated that these magnesium compounds were reactive at pH's normally in the rumen although reactivity decreased with increasing pH. Intraruminal doses of feed grade magnesium oxide A and calcium carbonate did not change rumen fluid pH for other compounds ranked: feed grade magnesium oxide B less than magnesium carbonate less than heavy magnesium oxide. Feeding of heavy magnesium oxide or magnesium carbonate increased rumen fluid pH as compared to the control diet. Feeding feed grade magnesium oxide B in three quantities to cattle resulted in proportional increased in fecal pH and fluidity of feces. Two feed grade magnesium oxides differed in their ability to neutralize acid in the rumen.

The relative efficiency of two orders for training autistic children in the expressive and receptive use of manual signs.

Using simultaneous communication (speech plus gesture), each of four nonverbal autistic children were taught the receptive and expressive use of eight signed words. In a within-subject comparison, each child was taught four words expressively (signing) first and then receptively, and four other words receptively first and then expressively (signing). The results indicated (1) that it took fewer trials to teach expressive and receptive use when teaching was done in the order expressive then receptive; (2) the teaching of expressive use facilitated the learning of receptive use; (3) the teaching of receptive use interfered with the learning of expressive use; and (4) by the end of training, good receptive control by the spoken word alone, had developed.