Prognosis in carcinoma of the urinary bladder based upon tissue blood group abh and Thomsen-Friedenreich antigen status and karyotype of the initial tumor.

Several markers of initial bladder carcinomas described recently may be clinically significant predictors of biological behavior of future recurrences. Comparison of the marker systems and assessment of the value of using multiple markers have been difficult, because the various markers have been studied in different patients. In this study, we compared four markers [chromosome mode, marker chromosomes, and expression of the ABH "blood group" antigens and the Thomsen-Friedenreich antigen (using immunoperoxidase or lectin immunoperoxidase methods)] in 39 patients presenting initially with low-stage bladder carcinoma and followed 3 to 11 years or until deep muscle invasion occurred. Each of the markers was significantly related to subsequent recurrences with deep muscle invasion, and each marker system was able to identify those patients with a very low risk of subsequent invasion. For detection of a subpopulation of patients with Grade II carcinomas who were at high risk for development of subsequent invasion, combinations of markers, especially hyperdiploidy and abnormal expression of the Thomsen-Friedenreich antigen, were significantly more effective than any single marker system.

Activation and inhibition of dextransucrase by calcium.

Initial rate kinetics of dextran synthesis by dextransucrase (sucrose:1,6-alpha-D-glucan-6-alpha-D-glucosyltransferase, EC 2.4.1.5) from Leuconostoc mesenteroides NRRL B-512F showed that below 1 mM, Ca2+ activated the enzyme by increasing Vmax and decreasing the Km for sucrose. Above 1 mM, Ca2+ was a weak competitive inhibitor (Ki = 59 mM). Although it was an activator at low concentration, Ca2+ was not required for dextran synthesis, either of main chain or branch linkages. Neither was it required for sucrose hydrolysis, acceptor reactions, or enzyme renaturation after SDS-polyacrylamide gel electrophoresis. A model for dextran synthesis is proposed in which dextransucrase has two Ca2+ sites, one activating and one inhibitory. Ca2+ at the inhibitory site prevents the binding of sucrose.

Functional molecular size and structure of dextransucrase by radiation inactivation and gel electrophoresis.

Robyt et al. have proposed a mechanism for dextransucrase in which dextran is synthesized by the cooperative action of two equivalent nucleophiles (Robyt, J.F., Kimble, B.K. and Walseth, T.F. (1974) Arch. Biochem. Biophys. 165, 634-640). To distinguish between the possibilities that the enzyme is a monomer bearing both nucleophiles, or a dimer with each subunit bearing one nucleophile, the molecular weight of the enzyme was determined by SDS-polyacrylamide gel electrophoresis and by radiation inactivation. Two major forms of dextransucrase from Leuconostoc mesenteroides NRRL B-512F were found on SDS-polyacrylamide gel electrophoresis, with Mr 177 000 and 158 000, and sometimes a minor form with Mr 168 000. No form of dextransucrase smaller than Mr 158 000 was found, either in the presence or absence of dextran T10, although levansucrase was detected at Mr 92 000 and 116 000. On irradiation with 60Co, dextransucrase behaved as a single species with a maximum size of Mr 201 000. Because Mr 201 000 is much smaller than the minimum dimer size of Mr 316 000 (= 2 X 158 000), it is concluded that both nucleophiles are probably located on the same peptide, rather than one on each subunit of a dimer, and that peptide association is probably not required for dextran synthesis.

Stabilization of dextransucrase from Leuconostoc mesenteroides NRRL B-512F by nonionic detergents, poly(ethylene glycol) and high-molecular-weight dextran.

Dextransucrase (sucrose: 1,6-alpha-D-glucan 6-alpha-D-glucosyltransferase, EC 2.4.1.5) (3 IU/ml culture supernatant) was obtained by a modification of the method of Robyt and Walseth (Robyt, J.F. and Walseth, T.F. (1979) Carbohydr. Res. 68, 95-111) from a nitrosoguanidine mutant of Leuconostoc mesenteroides NRRL B-512F selected for high dextransucrase production. Dialyzed, concentrated culture supernatant (crude enzyme) was treated with immobilized dextranase (EC 3.2.1.11) and chromatographed on a column of Bio-Gel A-5m. The resulting, purified enzyme lost activity rapidly at 25 degrees C or on manipulation, as did the crude enzyme when diluted below 1 U/ml. Both enzyme preparations could be stabilized by low levels of high-molecular-weight dextran (2 micrograms/ml), poly(ethylene glycol) (e.g., 10 micrograms/ml PEG 20 000), or nonionic detergents (e.g., 10 micrograms/ml Tween 80). The stabilizing capacity of poly(ethylene glycol) and of dextran increased with molecular weight. Calcium had no stabilizing action in the absence of other additions, but reduced the inactivation that occurred in the presence of 0.5% bovine serum albumin or high concentrations (greater than 0.1%) of Triton X-100. In summary, dextransucrase could be stabilized against activity losses caused by heating or by dilution through the addition of low concentrations of nonionic polymers (dextran, PEG 20000, methyl cellulose) or of nonionic detergents at or slightly below their critical micelle concentrations.

Zn2+ regulation of ornithine transcarbamoylase. I. Mechanism of action.

Ornithine transcarbamoylase catalyzes the formation of L-citrulline from carbamoyl phosphate and L-ornithine. The anabolic enzyme from Escherichia coli is composed of three identical subunits and resembles, in both primary and quaternary structures, the catalytic unit of aspartate transcarbamoylase. However, ornithine transcarbamoylase has no regulatory subunits. Although this enzyme does not bind its substrates co-operatively, fluorescence spectroscopic experiments show that zinc adds allosterically to the free enzyme. The metal binding process is dictated by deprotonation of an enzymic group with a pKa less than 7. The saturation binding curve of the metal ion is sigmoidal and yields a Hill coefficient of 1.6 at pH 8.5 and 25 degrees C. In the absence of substrates, zinc further promotes a slow enzyme isomerization, which occurs with a first-order rate constant of 7 min-1; thus, the metal is a slow, tight-binding inhibitor. The isomerized enzyme is inactive and contains three zinc ions. When the enzyme is first bound with carbamoyl phosphate, steady-state kinetic assays reveal that zinc again binds co-operatively to the binary enzyme complex, with a Hill coefficient of 1.5, but the metal ion now behaves simply as a classical, reversible inhibitor; it is competitive against L-ornithine, non-competitive against carbamoyl phosphate, and induces no enzyme isomerization. However, as a result of the competition between zinc and L-ornithine for the same site on the enzyme, the L-ornithine saturation curve becomes sigmoidal. Displacement of the allosteric zinc from the enzyme by L-ornithine is the cause of co-operative addition of this substrate. The combined results suggest that zinc regulates ornithine transcarbamoylase via two routes: (1) as an allosteric cofactor of the substrate-bound enzyme in mediating site-site interactions; and (2) as a slow, tight-binding inhibitor of the free enzyme in inducing inactivation. The concentration of zinc that is effective for action is in the micromolar range. The finding that E. coli ornithine transcarbamoylase can be induced to express co-operativity in binding its substrates has recently been confirmed by site-directed mutagenesis experiments. When the active site residue Arg106 is altered to a glycine, the resultant mutant enzyme exhibits both homotropic and heterotropic interactions towards its substrates. In view of the quaternary structure of holoenzyme aspartate transcarbamoylase, the "silent" co-operativity of ornithine transcarbamoylase is of particular interest in the study of evolution of complex, regulatory proteins.

Insulin resistance and associated dysfunction of resistance vessels and arterial hypertension.

Insulin resistance (IR) has profound, negative effects on the function of arteries and arterioles throughout the body and leads to arterial hypertension and vascular occlusive diseases such as heart attacks and strokes. IR affects arteries and arterioles at both the endothelium and smooth muscle levels. One major, underlying mechanism of vascular dysfunction appears to involve the augmented generation, availability and subsequent actions of reactive oxygen species (ROS). Thus, application of superoxide dismutase (SOD), a specific scavenger of superoxide anion, is able to immediately restore normal dilator responsiveness in IR arteries. In some but not all circulations, however, other factors such as increased production of and actions by constrictor agents such as endothelin also appear to restrict normal dilator responses. The basis of ROS-mediated vascular dysfunction in IR is not completely understood, but inflammatory processes throughout the arterial wall appear to be involved. Treatments involving behavioral approaches, such as changes in diet, weight loss, and regular exercise, and pharmacological approaches, involving the use of insulin-sensitizing agents or statins, appear to offer benefits against the detrimental vascular effects of IR. Nonetheless, the most effective approach appears to involve prevention of IR via adoption of a healthy lifestyle by young people.

Metformin improves vascular function in insulin-resistant rats.

This study assessed the effect of metformin treatment on insulin, mean arterial pressure (MAP), and endothelial function in insulin-resistant (IR) rats. In addition, we assessed the direct effect of metformin in vitro. Sprague-Dawley rats were randomized to control (n=28) or IR (n=28) groups. Rats were further randomized to receive metformin (300 mg/kg) or placebo for 2 weeks. MAP and insulin were measured. Subsequently, a third-order branch of the superior mesenteric artery was isolated, and endothelial function was assessed. Specifically, dose-response experiments of acetylcholine (ACh) with or without N-nitro-L-arginine (LNNA) were performed. For in vitro experiments, mesenteric arteries were removed from untreated control and IR rats and treated with metformin (100 micromol/L) before ACh+/-LNNA. MAP and insulin levels were improved in IR-metformin compared with IR-placebo rats. Maximal relaxation (E(max)) to ACh was enhanced in IR-metformin (92+/-2%) compared with IR-placebo rats (44+/-4%) (P<0.05). Relaxation in response to ACh+LNNA was greater in IR-metformin (33+/-4%) than in IR-placebo rats (12+/-4%) but remained depressed compared with control rats (E(max)=68+/-5%). The control group was not affected by metformin. In vitro treatment of arteries with metformin in response to ACh produced results similar to those in the experiments with metformin-treated rats. Although metformin improves metabolic abnormality in IR rats, this action does not appear to mediate its effect on vascular function. Both in vivo and in vitro metformin improved ACh-induced relaxation in IR rats to control levels, apparently through nitric oxide-dependent relaxation. These data suggest that metformin improves vascular function through a direct mechanism rather than by improving metabolic abnormalities.

Hemodynamic responses to DOCA in young pigs.

Hemodynamic variables were measured in 20 young pigs; thirteen received subcutaneous implantations of desoxycorticosterone acetate (DOCA) impregnated in Silastic strips, seven received implants of Silastic strips alone and served as controls. No salt was added to the standard diet of either group. Mean arterial pressure (MAP) rose in a regular pattern in the DOCA-treated pigs, reaching on the average a level significantly greater than that of the control group 48 hours after the implantation. Pressure continued to rise, reaching a plateau 38% above that of the preimplant value 2 weeks later. In some pigs the MAP elevation was caused by an increase in cardiac output (CO); in others it was caused by an increase in total peripheral resistance (TPR). An increase in central venous pressure occurred in many DOCA-treated pigs regardless of whether the increase in MAP was caused by an increase in CO or in TPR. The results indicate that it is arterial pressure per se that is the regulated variable in this model of mineralocorticoid hypertension. The regulating system, whether it resides in the kidney or in the central nervous system, elevates pressure by effecting increases in either CO or TPR.

DNA sequencing by capillary electrophoresis using short oligonucleotide primer libraries.

Two strategies for DNA sequencing by primer walking using short oligonucleotide primer libraries have been successfully employed along with capillary electrophoresis using replaceable polymer solutions of linear polyacrylamide and fluorescence detection. A 3.5-kb stretch of the single-stranded M13mp18 template was sequenced with T7 PRISM dye-terminator/Sequenase chemistry. An in-house base-calling program offered read lengths of roughly 450 bases with an average of 97.8% accuracy.

Intravascular lipoleiomyomatosis: a report of two cases.

Two cases of intravascular leiomyomatosis (IVL) with histologic features of a lipoleiomyoma (LPL) are reported. Both tumors arose from preexisting uterine leiomyomata. One tumor was found incidentally in a uterus removed for leiomyomata. The other tumor extended up the inferior vena cava into the right side of the heart and presented as a cardiac mass. Although LPL is considered to be a benign lesion, IVL recurs in approximately 10% of reported cases, and must be distinguished from low-grade endometrial stromal sarcoma and leiomyosarcoma with vascular invasion. The combination of features in these cases lends support to the theory that IVL may arise by intravascular extension of a preexisting leiomyoma.

Endotoxemia alters splanchnic capacitance.

The splanchnic circulation constitutes a major portion of the total capacitance vasculature and may affect venous return and subsequently cardiac output during low output states. This study assessed the effects of rapid (10 microg/kg over 5 min) and slow (10 microg/kg over 60 min) induction of endotoxin (Escherichia coli) shock on splanchnic blood volume in 8 farm swine. Blood volume was measured by using Tc99m-labeled erythrocytes and radionuclide imaging. Baseline arterial pressure (MAP), central venous pressure (CVP), and liver, splenic, mesenteric and total splanchnic volumes were stable during the 30-min baseline. Approximately 30 min after the rapid endotoxin infusion, splenic volume decreased by 45%, whereas liver volume increased by 40% and MAP decreased by 60% (P < 0.01). The reduction in splenic volume occurred within 10 min of the endotoxin infusion, whereas liver volume changes occurred after MAP reduction. The slow endotoxin infusion also reduced splenic volume by approximately 50% (P = 0.05), whereas MAP declined by 30% (P < 0.05). However, the slow endotoxin infusion lowered liver volume (P < 0.05). Mesenteric volume was unaffected by the fast or slow endotoxin infusion. Total splanchnic volume was unaffected by the fast infusion but decreased by 37% in the slow infusion group (P < 0.05). In summary, E. coli endotoxin reduces splenic blood volume and increases liver blood volume after acute hypotension ensues. Endotoxin does not increase total splanchnic blood volume and may actually decrease total splanchnic volume in the absence of circulatory collapse. This endotoxin shock model is not associated with blood volume pooling in the splanchnic capacitance circulation.

Effects of therapy on carcinoembryonic antigen activity in the urines of patients with cancer of the bladder.

Carcino-embryonic antigen (CEA) levels were quantitated in specimens of urine for 16 patients with invasive transitional-cell carcinoma of the urinary bladder. Four of the patients had received x-irradiation to the bladder and four had been treated with the radiomimetic agent, thiotepa. Urinary CEA levels in these patients (3.7 +/- 2.4 ng/ml) were significantly lower (t = 6.17, P less than .001) than levels from a similar group of eight patients who had not been treated with radiotherapy (20.3 +/- 8.7 ng/ml). These results suggest that "false-negative" urinary CEA levels may, in some cases, be associated with previous radiotherapy.

Clinical trial of a chemical test for bacteriuria.

A chemical test for the detection of bacteriuria-Uriglox-has been compared with the results obtained on culturing urine obtained by suprapubic aspiration in 351 pregnant or puerperal women. The results of this comparison show a correlation of 96.9%, both false positive and false negative results occurring.

Structural and serological studies of lipopolysaccharides from proposed new serotypes (O25 and O26) of Serratia marcescens.

The surface polysaccharides of the two most recently proposed O-serotype strains of Serratia marcescens, O25 and O26, were characterised in terms of their chemical structure and immunological reactions. No polymer was isolated from O25, which was shown to lack both capsular K-antigen and smooth, O-antigenic lipopolysaccharide. A neutral polysaccharide was isolated from O26 and shown to be a polymer of rhamnose and N-acetylgalactosamine of the type previously found in the O9 and O15 reference strains. Serological cross-reactions among all three strains were demonstrated by using both whole-cell enzyme-linked immunosorbent assay and immunoblotting of lipopolysaccharide resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. No acidic polysaccharide was found in O26 and this was consistent with the absence of an immunogenic capsule. Thus, neither strain qualifies for inclusion as a new serotype in either an O-typing or a K-typing scheme.

Pathology of superficial bladder cancer with emphasis on carcinoma in situ.

The coexistence of carcinoma in situ in flat epithelium adjacent to tumors is prognostically significant and is associated with an increased incidence of tumor recurrence and invasion. Recent investigations have been aimed at finding markers that will help identify flat areas of dysplasia or low-grade papillary transitional cell carcinomas that have a high potential to evolve into invasive tumors. Both DNA and karyotype analyses, as well as cell surface markers, have been examined in some detail and could have clinical value in certain settings. The tumor DNA index as measured by flow cytometry of nuclei retrieved from deparaffined sections may be particularly useful as a predictor of tumor recurrences and, possibly, tumor invasion as well. The diagnosis of superficial disease rests on urine cytology and the histopathologic assessment of tissue biopsies; however, intra- and inter-observer reproducibility of tissue and cytologic diagnoses by pathologists is a significant problem. The application of new technologies, such as flow cytometric analysis of deparaffined nuclei, may reduce the subjectivity involved in the light microscopic assessment of pathology specimens.

Carcinoma in situ: comments on the pathobiology of a paradox.

Carcinoma in situ of the urinary bladder has been recognized as a pathologic entity for over a quarter of a century, yet its biologic and clinical significance is controversial. It has been established that the presence of areas of carcinoma in situ in bladders harboring tumors heralds a relatively poor prognosis. However, the prognostic significance of carcinoma in situ in patients without prior or current solid tumors remains open to question. From the standpoint of cancer biology, the possibility that a morphologic mimicker of carcinoma in situ lacks the metabolic machinery or crucial structural components required to complete the process of neoplastic transformation raises interesting cells. The term carcinoma paradoxicum is introduced to describe functionally benign but morphologically anaplastic intra-epithelial neoplasms with marginal malignant potential.

A specimen mount for small laryngeal biopsies.

Accurate histologic interpretation of small laryngeal biopsies is often obfuscated by tangential sectioning of the specimen. The natural tendency of the tissue specimen to curl and suboptimal orientation of the specimen account for the tangential cuts. Use of a biopsy specimen mount eliminates this problem. The biopsy specimen mount also permits accurate determination of tumor involvement of deep and peripheral margins, a useful feature in the management of small areas of leukoplakia of the vocal cords. The biopsy specimen mount is therefore helpful in the endoscopic surgical management of small areas of leukoplakia of the vocal cords. The biopsy specimen mount is therefore helpful in the endoscopic surgical management of early glottic malignancy (T1s, T1), since therapy can be individualized and planned rationally with precise determination of margin involvement.

A maximum-likelihood base caller for DNA sequencing.

The procedures used to sequence the human genome involve the electrophoretic separation of mixtures of dioxyribonucleic acid (DNA) fragments tagged with reporting groups, usually fluorescent dyes. Each fluorescent pulse which arrives from an optical detector corresponds to a nucleotide (base) in the DNA sequence, and the subsequent process of base detection is known as base calling. Generating longer and more accurate sequences in the base-calling process will reduce the high cost of DNA sequencing. This paper presents an automated base-calling algorithm, referred to as maximum-likelihood base caller (MLB), which is based on maximum likelihood equalization for digital communication channels. Based on 125 experimental datasets, MLB averaged up to 40% fewer errors than the widely used ABI base caller from the Applied Biosystems Division of PE Corporation. MLB's accuracy rivaled that of another well-known base caller, Phred, surpassing it on datasets with high background noise.

Milligram to gram scale purification and characterization of dextransucrase from Leuconostoc mesenteroides NRRL B-512F.

A sequence of dextranase treatment, DEAE-cellulose chromatography, affinity chromatography on Sephadex G-200, and chromatography on DEAE-Trisacryl M has been optimized to give a dextransucrase preparation with low carbohydrate content (1-100 micrograms/mg protein) and high specific activity (90-170 U/mg protein) relative to previous procedures, in 30-50% yield. Levansucrase was absent after DEAE-cellulose chromatography, and dextranase was undetectable after Sephadex G-200 chromatography. The method could be scaled up to produce gram quantities of purified enzyme. The purified dextransucrase had a pH optimum of 5.0-5.5, a Km of 12-16 mM, and produced the same lightly branched dextran as before purification. The purified enzyme was not activated by added dextran, but the rate of dextran synthesis increased abruptly during dextran synthesis at a dextran concentration of approximately 0.1 mg/mL. The enzyme had two major forms, of molecular weight 177,000 and 158,000. The 177,000 form predominated in fresh preparations of culture supernatant or purified enzyme, whereas the amount of the 158,000 form increased at the expense of the 177,000 form during storage of either preparation.

Structure of the O10 antigen of Stenotrophomonas (Xanthomonas) maltophilia.

A polysaccharide containing L-rhamnose and L-xylose was isolated from the lipopolysaccharide extracted from the cell walls of the reference strain for Stenotrophomonas (Xanthomonas) maltophilia serogroup O10. By means of NMR studies and methylation analysis, the repeating unit of the polymer was identified as a branched tetrasaccharide of the structure shown. [formula: see text]