Pseudomyxoma peritonei. Radiologic features

Diagnostic radiologic features of pseudomyxoma peritonei consist of diffusely scattered plaques of calcifications in the abdomen, poorly defined soft tissue masses and ascites on plain abdominal radiographs, characteristic scalloping of the hepatic margin, numerous multilocular cystic masses with rims of curvilinear calcifications and compression of abdominal viscera without evidence of invasion at computed tomography, and an echogenic mantle with ascitic septations at ultrasonography. In an appropriate clinical setting, this spectrum of radiologic features is highly specific for the diagnosis of pseudomyxoma peritonei.

Herpetic esophagitis: a diagnostic challenge in immunocompromised patients

Viral esophageal infection is common in immunocompromised patients. Twelve patients with esophagitis secondary to herpes viruses are described. Odynophagia, dysphagia, and gastrointestinal bleeding were the most common symptoms. Multiple infections particularly with candida were present in three of the 12 cases (25%). Typical "volcano ulcers" at endoscopy and discrete diffusely scattered shallow ulcers seen on double contrast esophagram are highly suggestive of herpetic esophagitis. Single contrast esophagram plays no specific role in the diagnosis of herpetic esophagitis. An analysis of clinical, endoscopic, radiological, and pathological features is presented.

Ischemic colitis masquerading as colonic tumor: an unusual endoscopic presentation

A case of ischemic colitis masquerading as colonic submucosal tumor with no superficial mucosal lesion is reported. This unusual and less well known endoscopic presentation of colonic ischemia is emphasized and a rational approach to the management of ischemic colitis is discussed.

The esophagus after endoscopic pneumatic balloon dilatation for achalasia

The changes seen on contrast esophagrams after endoscopic pneumatic balloon dilation for the treatment of achalasia are described and illustrated. Sixteen patients had esophagrams within 24 hr after dilation and follow-up esophagrams were obtained 6-24 months later. The radiographic features evaluated in the early postdilation period included detection of esophageal perforation, diameter of the esophagogastric channel, proximal esophageal dilatation, mucosal integrity, and emptying dynamics of the esophagus. Fourteen patients (88%) had immediate symptomatic improvement of dysphagia. The mean increase in diameter of the esophagogastric channel was 6.5 mm (range, 4.8-9 mm) relative to a pretreatment esophagram. Emptying dynamics of the esophagus improved significantly in 12 patients (75%). One patient developed esophageal perforation requiring surgery. On the follow-up esophagrams obtained 6-24 months later, the evaluation was for sustained dilatation of esophagogastric channel, decrease in esophageal dilatation, and improved emptying dynamics of the esophagus. The effective esophagogastric channel diameter of 8-10 mm correlated well with improved clinical response in 88% of the patients.

Antibody to Epstein-Barr virus-specific DNase as a marker for the early detection of nasopharyngeal carcinoma

We have previously shown that high levels of antibody to Epstein-Barr virus (EBV)-specific DNase may be a useful marker for the early diagnosis of nasopharyngeal carcinoma (NPC). Sera from 3,368 males in an area with a high risk for the development of NPC were examined for the presence of antibody to EBV-specific DNase activity. Significant levels of the antibody were found in 430 of these sera. As a result, 32 individuals have attended the out-patient department of otolaryngology for clinical examination. Among them, one individual was found to have a stage II nasopharyngeal carcinoma. This result supports the value of determination of antibody to EBV-specific DNase as a marker for the early detection of NPC.

Characteristics of hepatitis B surface antigen produced in yeast

We have constructed an expression plasmid for regulated expression of the hepatitis B surface antigen gene in yeast using promoter of the yeast Pho5 gene. In the yeast transformants, the monomeric HBsAg (22K dalton) was estimated to constitute approximately 3% of the total proteins. On extraction, the HBsAg was found to have a buoyant density of 1.18 g/ml and an Sw.20 value of 54. Electron microscopy revealed particles of heterogeneous size ranging from 18-28 nm. When the yeast HBsAg was used to immunize guinea pigs, the anti-HBsAg antibodies produced could react with human serum HBsAg.

Identity of acyl group conformations in the active sites of papain and cathepsin B by resonance Raman spectroscopy

Resonance Raman spectroscopic data provide conclusive evidence for the existence of an acyl-enzyme intermediate during the reaction of a thionoester substrate, N-methyloxycarbonylphenylalanylglycine methyl thionoester (CH3OC(=O)-Phe-NHCH2C(=S) OCH3), with cathepsin B from porcine spleen. The resonance Raman spectrum of CH3OC(=O)-Phe-NHCH2C(=S)S-cathepsin B, where the thiol S is from the active-site cysteine residue, is compared to that of the corresponding papain acyl-enzyme. Within the limits of experimental error (+/-2 cm-1 for peak positions), there are no detectable spectral differences. Since the resonance Raman spectrum is sensitive to the torsional angles in the glycinic bonds and the cysteine linkages, the conformations are identical in those parts of the acyl-enzymes where chemical transformation occurs. A conformational analysis of the model compound CH3OC(=O)-Phe-NHCH2C(=S)SC2H5 demonstrates that the dithioacyl group in both dithioacyl-enzymes is present as a single population of a form known as conformer B. Conformer B is characterized by a small torsional angle about the glycinic NHCH2-CS(thiol) bond such that the nitrogen and S (thiol) atoms are in close contact. This conformer is widespread among the dithioacyl intermediates of plant cysteine proteinases, and it is apparent that the same chemistry is retained in a mammalian cysteine proteinase. Steady-state kinetic parameters are also reported for CH3OC(=O)-Phe-NHCH2C(=S)OCH3 reacting with papain and cathepsin B. The similarity of the Kcat values, 0.53 and 1.15 s-1, for papain and cathepsin B, respectively, provides further evidence for a conserved deacylation process.

Comparative resonance Raman spectroscopic and kinetic studies of acyl-enzymes involving papain, actinidin and papaya peptidase II

Resonance Raman spectra are reported for a series of dithioacyl-enzymes involving actinidin (EC 3.4.22.14) and papaya peptidase II (the more basic monothiol cysteine proteinase of Carica papaya). The acyl groups are N-benzoylglycine and N-(beta-phenylpropionyl)glycine containing C = S or 13C = S at the ester function. Comparison of the data with those for the corresponding papain (EC 3.4.22.2) analogues [Storer, Lee & Carey (1983) Biochemistry 22, 4789-4796] allows us to define the conformation of the dithioacyl group in the catalytic site. In each case the dithioacyl group is bound in a single conformation known as conformer B, in which the glycinic nitrogen atom comes into close contact with the sulphur atom of the catalytic-site cysteine residue. For the N-(beta-phenylpropionyl)glycine dithioacyl-enzymes the torsional angles of the NH-CH2-C(= S) bonds assume values typical of an essentially relaxed non-strained state. However, for the N-benzoylglycine dithioacyl-enzymes there is evidence for a slightly perturbed conformer B, and the perturbation is most pronounced for N-benzoylglycine dithioacyl-actinidin. Values of k+2/Ks and k+3 for the reactions of papain, actinidin and papaya peptidase II with N-benzoylglycine and N-(beta-phenylpropionyl)glycine methyl thionoesters were obtained by a pre-steady-state kinetic study. Wide variation was found in k+2/Ks, but the values of k+3 are all similar. This general picture is supported by the results from a steady-state kinetic study of the reactions of the three enzymes with N-benzoyl-L-arginine-p-nitroanilide and with N-benzyloxycarbonyl-L-lysine p-nitrophenyl ester. The similarity of the values of k+3, together with the invariance of conformer B geometry at the P1 site, suggests that the chemistry of the deacylation process is highly conserved among these three cysteine proteinases.

[A preliminary study on epidemiology of fasciolopsiasis in Tainan Hsien, south Taiwan]

Stool samples of 817 children (grades 4-6) from 3 primary schools, were collected and examined by the antiformin-ether concentration technique. Results showed no cases of Fasciolopsis were found from Liu-Ying primary school (Liu-Ying Hsiang), but infection rates of this fluke were found to be 13.0% and 3.5% for Ho-Chien and Tung-Hsing primary schools (Hsia-Ying Hsiang) respectively. Fourteen infected children had recent experience of eating raw water caltrops. On the other hand, only 8(21.6%) of 37 non-infected children had eaten raw water caltrops. Examination of intermediate host (Segmentina hemisphaerula, Trapa bispinosa) results showed that neither cercaria nor metacercaria was found. Intestines and stool samples from pigs were examined for worms and eggs of Fasciolopsis, the results were also negative.

[Purification of human fibronectin by precipitation and immunoadsorption]

Two types of human plasma fibronectin concentrate were obtained by simple, large scale, precipitation methods. Concentrate 1 contains 90% pure fibronectin in a mainly dimeric form. This easy, high yield method provides a functional fibronectin suitable for intravenous therapeutic purposes in deficient patients. Concentrate 2 contains 95-98% pure fibronectin with minimal amounts of fibronectin monomer and degradation products. It seems well adapted to serum free cultures of human cells. A third preparation of an apparently pure fibronectin has also been obtained by immuno-adsorption with a Sepharose 4B column to which has been coupled an anti-fibronectin monoclonal antibody. The capture of dimer, monomers and degradation products by this antibody and their release at pH 2.4 has been demonstrated by gel transfer on nitrocellulose sheet revealed by another monoclonal anti-fibronectin antibody labelled with peroxidase.

Kinetic mechanism of threonyl-tRNA synthetase from human placenta

Using purified enzyme and homologous tRNA, we have investigated the order of substrate binding and product release for the human placental threonyl-tRNA synthetase by isotope exchange, initial velocity, dead-end inhibition and product inhibition studies. The kinetic patterns obtained from these studies are consistent with a unique Bi Uni Uni Bi ping-pong mechanism. The order of addition of the first two substrates ATP and threonine is random, while the release of products follows an obligatory sequence, with AMP as the last product to dissociate from the enzyme.

Purification and subunit structure studies of human placental threonyl-tRNA synthetase

Human threonyl-tRNA synthetase has been purified from full-term placenta over 5000-fold with a 13% overall yield by a combination of affinity chromatographic methods and conventional procedures. The product was apparently homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme catalyzed the esterification of approximately 3500 nmol L-threonine to tRNA per min per mg of protein at 37 degrees, corresponding to a molecular activity of approximately 700/min. The apparent molecular weight of the native enzyme ranged from 210000 to 220000 by gel-filtration on Sephadex G-200, and was either approximately 110000 or 228000 by sucrose gradient centrifugation for different preparations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated a single band of molecular weight 85000 or 115000 for different preparations. These results suggest that human placental threonyl-tRNA synthetase has a subunit structure of the type alpha 2 with a subunit molecular weight of about 100000. However, some other molecular forms with lower specific activity were also found to exist under certain conditions.

Isolation of genotypic variants of Autographa californica nuclear polyhedrosis virus

A nuclear polyhedrosis virus (MNPV) isolated from a lepidopteran (Noctuidae) insect, Autographa californica, was cloned by successive plaque purification using virions containing only one nucleocapsid per envelope as inoculum. The ability to clone the virus by this method was demonstrated by the isolation of nondefective, genotypic variants of the virus with similar but not identical restriction endonuclease fragment patterns. Five distinct variants were identified by genotypic analysis with HindIII, EcoRI, SalI, and Bam HI restriction endonucleases. The characteristic genotype of each variant was maintained upon passage in insect larvae. The isolation of these virus variants demonstrates (i) the heterogeneity of the uncloned virus preparation and (ii) the ability to clone MNPVs by plaque purification of media-derived nonoccluded virions. The A. californica MNPV is being considered for commercial use as a pesticide in the United States, and the cloning of the virus, in view of the heterogeneity detected, may be advisable. The cloning and genotype analyses are also significant with regard to understanding the genetic nature of multiply embedded NPVs (those NPVs containing more than one nucleocapsid per envelope in the occluded form of the virus) and indicate that further genetic analysis of these viruses is possible.

The starfish (Patiria and Pisaster) oocyte: a model system for the study of hormone-surface interaction in oogenesis

Studies were made to determine if the starfish (Patiria and Pisaster) oocyte could serve as a model system for investigations of hormone-surface interactions in eucaryotic cells. Treatment of starfisch oocytes with maturation inducing hormone, 1-methyladenine, was observed by scanning electron microscopy to induce surface alteration. The action of the hormone was dependent on the presence of the cation Ca++. Although caffeine, theophylline, and theobromine supposedly inhibit maturation of oocytes, studies using the starfish oocyte showed that theobromine does not inhibit maturation and the inhibition caused by caffeine and theophylline is reversible. Other studies using the starfish oocyte and tritiated 1-methyladenine showed that the hormone does not dissociate from the oocyte once bound, and that the oocyte surface may have multiple receptors for 1-methyladenine. From these studies it was concluded that the starfish oocyte is a useful model for studies of hormone-surface interactions in eucaryotic cells.

Multiple molecular forms of cysteinyl-tRNA synthetase from rat liver: purification and subunit structure

Cysteinyl-tRNA synthetase (L-cysteine:tRNACys ligase (AMP-forming), EC 6.1.1.16) has been purified from rat liver in 23% overall yield. The enzyme was resolved by hydroxyapatite chromatography into three active forms (Fractions CRS-1, CRS-2 and CRS-3). The total activity ratio was about 0.7:2:1. The fractions CRS-2 and CRS-3 contained no other detectable aminoacyl-tRNA synthetase activity. CRS-2 was homogeneous by polyacrylamide gel electrophoresis, CRS-3 gave two active bands with mobilities corresponding to those of CRS-1 and CRS-2. The molecular weight of CRS-2 was about 240 000 by electrophoretic mobilities on the gels of various porosity, and 115 000-140 000 by sucrose gradient centrifugation. By gel-filtration, CRS-1, CRS-2 and CRS-3 exhibited apparent molecular weights of 122 000, 235 000 and 300 000, respectively. By sodium dodecyl sulfate gel electrophoresis, both CRS-2 and CRS-3 gave a single major band of 120 000 daltons. Stoichiometric study of cysteinyl adenylate formation indicated that CRS-2 has two active sites per molecule. These results are consistent with a dimeric structure of the type alpha2 for the major form of rat liver cysteinyl-tRNA synthetase, composed of two probably identical subunits of about 120 000 daltons. Available evidence also suggests that CRS-1 and CRS-3 are alpha and alpha3 (or alpha4), respectively.

Reactions of 1-substituted 2,4-dinitrobenzenes with diamines and anilines : the question of base catalysis by amines

Calculated second-order rate constants for the reactions of ethane-1,2- diamine and propane-1,3-diamine with 1-chloro-2,4-dinitrobenzene in methanol and with 2,4-dinitro-1-phenoxybenzene in dioxan/water (3 : 2) are mildly dependent on amine concentration. The catalysis is no weaker than that for monoamines and this is adduced as evidence suggesting that it does not represent base catalysis in the second stage of the intermediate-complex mechanism for activated aromatic nucleophilic substitution. ��� The aromatic amines m-anisidine, aniline, p-toluidine and p- anisidine mildly catalyse their own aminolysis reactions with 1-fluoro- 2,4-dinitrobenzene in methanol; the catalytic effects are not significantly smaller than that for the more strongly basic aliphatic amine butylamine. Contrary to an earlier report, there is no kinetic evidence to support charge-transfer complexing in the reaction of aniline with 1-fluoro-2,4-dinitrobenzene.

Inhibition of certain deoxyribonucleic acid viruses by liver extracts

A proteinaceous substance was detected in the liver of several animal species that inhibited the multiplication of certain deoxyribonucleic acid, but not ribonucleic acid, viruses. Preliminary experiments suggested that its site of action was not extracellular. It did not inhibit virus by interfering with adsorption to cells. It was suggested that this inhibiting substance acts directly upon cells by interfering with viral synthesis.

Viral antigens in differentiating muscle colonies after infection with Rous sarcoma virus in vitro

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