Defect In Conjugation Research Articles

Dynamics of bond conjugation defects in trans-polyacetylene

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDynamics of bond conjugation defects in trans-polyacetyleneHans Thomann and Gregory L. BakerCite this: J. Am. Chem. Soc. 1987, 109, 5, 1569–1570Publication Date (Print):March 1, 1987Publication History Published online1 May 2002Published inissue 1 March 1987https://doi.org/10.1021/ja00239a047RIGHTS & PERMISSIONSArticle Views114Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (296 KB) Get e-Alerts Get e-Alerts

Non-solitonic conductivity in polyacetylene

Abstract Systematic investigations of the temperature dependences of the d.c. and microwave conductivity of polyacetylene doped with various species are reported. These results are discussed within a model where the measured quantities are a superposition of different conduction mechanisms. At low dopant concentrations carrier hopping between localized defect states dominates, while at high doping levels only the inter-fibrillar contact resistances are important. In an intermediate doping region the prevailing contribution to the conductivity is carrier tunnelling between highly conducting parts of the sample separated by less-conducting zones. There seems to be no doping regime in which carrier transport via mobile conjugational defects (solitons) plays a detectable role.

HepG2. A human hepatoblastoma cell line exhibiting defects in bile acid synthesis and conjugation.

We used capillary gas chromatography/mass spectrometry to demonstrate that a cell line derived from a well differentiated human hepatoblastoma, HepG2, synthesized and secreted the following bile acids (ng/10(7) cells/h): chenodeoxycholic acid (131.4), cholic acid (3.3), 3 alpha, 7 alpha-dihydroxy-5 beta-cholestan-26-oic acid (DHCA; 4.5), and 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-oic acid (THCA; 32.0). Deuterium from [7 beta-2H]7 alpha-hydroxycholesterol, which was added to the media, was incorporated into newly synthesized chenodeoxycholic acid, DHCA, and THCA, but not into cholic acid. Since THCA is a known precursor of cholic acid, these data suggest that HepG2 is specifically deficient in the side chain cleavage that transforms THCA into cholic acid. Greater than 90% of the bile acids synthesized and secreted by HepG2 were unconjugated. Conjugation could not be stimulated by the addition of glycine or taurine to the media. Approximately 30% of newly synthesized DHCA and THCA were sulfated. Chenodeoxycholic acid and cholic acid were not appreciably sulfated. In summary, cultured HepG2 cells synthesize bile acid, but in a pattern distinct from that of adult human liver. This cell line may be a model for studying pathways of human bile acid synthesis, conjugation, and sulfation.

Conductive polymers

Polymers with high, metal-like electric conductivity are presented as new materials with interesting applications. Thesesubstances have as a common feature extended systems of conjugated double bonds. The interest is focussed on conjugational defects. Experimental data are reviewed and critically analysed, particularly regarding to what extent do they support the treatment of the conjugational defects as quasi-particle and to what extent do they justify the description as solitions. Special attention is given is given to recent pulsed photoconductivity experiments which indicate that not only the dark conductivity but also the photoconductivity occurs via hopping processes, where the soliton concept does not lead to a deeper understanding of observable phenomena.

Unconjugated hyperepinephrinemia: a hallmark of hypertension imitating pheochromocytoma?

Hypertensive patients with elevated and hyperresponsive plasma norepinephrine and epinephrine (NE + E) associated with low conjugated NE + E were previously identified by determination of the sum of NE + E. Because of their excessive E but not NE responses to glucagon and also hypertension corresponding to E excess, we explored whether an elevated unconjugated E resulting from a selective E conjugation defect could be obscured by the sum of NE + E. We found that nine patients with elevated E (reflected by the normal 4:1 ratio of plasma NE to E reversed in favor of E), had, when compared to 31 patients with plasma NE exceeding E:1) lower plasma conjugated E (mean 0.03 vs 0.27 ng/ml, p less than 0.01), lower degree of E conjugation (8 vs 51%, p less than 0.01), and a higher maximum systolic (p less than 0.05), pulse pressure (p less than 0.02) and higher pulse rates (p less than 0.04), but no differences in the unconjugated and conjugated proportions of plasma NE; and 2) an absence of conjugated E throughout the circulation and relative preponderance of E over NE at sampling points close to the peripheral venous blood (p less than 0.05). The absolutely and relatively decreased plasma conjugated E in patients with E exceeding NE (without difference in conjugated NE) is a preliminary indication that a selective sulfoconjugating defect of E results in plasma E higher than NE in accordance with the hyper-beta-adrenergic features of their hypertension. Epinephrine, a circulating hormone, is more dependent on conjugated E reflect better this defect than those measuring the sum of NE and E.

Management of refractory chylous ascites by total parenteral nutrition

syndrome is suggested by the fact that four boys of the seven children from the family S. were afflicted by the disease and that eight boys died either at birth or shortly thereafter in the maternal family (Fig. 2). The genetic transmission and the combination of hepatic, renal, and neurologic abnormalities define the overall characters o f a metabolic disease. The few investigations effected enabled us to eliminate only the most common metabolic disease. Nevertheless, we postulate that the renal and neuromuscular disorders were secondary in nature, and that the principal site of metabolic disturbance, as suggested by the hepatic accumulation of pigments, was located in the liver and may be related to a defect of conjugation and elimination of a toxic endogenous metabolite? As their metabolites are known to be cytotoxic both to the nervous system and to the renal parenchyma, a congenital disorder of hepatic porphyrin could be seriously considered.

Bilirubin Metabolism in Congenital Nonhemolytic Jaundice

Extract: A Negro female with congenital nonhemolytic jaundice (Crigler-Najjar syndrome) was studied over a period of 15 months. During this period the plasma bilirubin concentration averaged 20.6 mg/100 ml. Administration of phenobarbital did not lower the bilirubin concentration. Studies with isotopically labeled bilirubin showed that phenobarbital had not increased the fractional rate of elimination of bilirubin, and the patient's bilirubin production rate while receiving phenobarbital therapy (3.5 mg/kg/24 hr) was not increased over that seen in normal individuals (3.8 \pm 0.6 mg/kg/24 hr, mean \pm sd). Multicompartmental analysis of the patient's labeled bilirubin clearance data, as well as that from two other reported cases of congenital nonhemolytic jaundice, did not furnish new information on pathways of bilirubin catabolism but did demonstrate that the fractional transfer rate of bilirubin from plasma to liver for all three subjects (0.42–0.87 hr-1) was reduced compared with the range seen in normal individuals (0.9–2.0 hr-1). This finding may reflect saturation of either the hepatic uptake process or intracellular binding sites, in the face of a serum bilirubin concentration 20–40 times normal. Menthol conjugation in the patient's parents was normal, unlike reported findings in parents of children with congenital nonhemolytic jaundice unresponsive to phenobarbital therapy. Labeled bilirubin clearances in the parents demonstrated an abnormality in the mother's pattern of clearance, whereas the father's clearance was normal. The patient was found to excrete normal amounts of testosterone conjugated with glucuronic acid, demonstrating that the defect in glucuronide conjugation does not include all physiological compounds. Speculation: Plasma clearance studies with labeled bilirubin can aid in the investigation of modes of inheritance of unconjugated hyperbilirubinemia.

Constitutional hepatic dysfunction (Gilbert's syndrome): A new definition based on kinetic studies with unconjugated radiobilirubin

Plasma clearance studies with unconjugated radiobilirubin were performed in eleven patients who had chronic unconjugated hyperbilirubinemia in the absence of structural liver disease. An abnormal clearance pattern, characterized by increased retention of isotope in the plasma at four hours (24.2±8.4 per cent, mean ± standard deviation; normal=5.0±1.9 per cent) and a reduction in hepatic bilirubin clearance (16±5 ml/minute; normal=47±10 ml/minute), was observed in all eleven cases, despite the fact that the mean red cell survival ranged from normal (112 days) to severely reduced (eleven days). Multicompartmental analysis suggests that the reduced hepatic bilirubin clearance is the result of a defect in both hepatic bilirubin uptake and conjugation. Twenty-one studies in a control group with anemia and/or hemolysis were indistinguishable from normal, indicating that neither of these factors was responsible for the abnormalities noted. These studies suggest that current diagnostic criteria for Gilbert's syndrome, which exclude patients with hemolysis, will result in an artificial distinction among patients with the same basic hepatic abnormality. Plasma clearance studies with unconjugated radiobilirubin were performed in eleven patients who had chronic unconjugated hyperbilirubinemia in the absence of structural liver disease. An abnormal clearance pattern, characterized by increased retention of isotope in the plasma at four hours (24.2±8.4 per cent, mean ± standard deviation; normal=5.0±1.9 per cent) and a reduction in hepatic bilirubin clearance (16±5 ml/minute; normal=47±10 ml/minute), was observed in all eleven cases, despite the fact that the mean red cell survival ranged from normal (112 days) to severely reduced (eleven days). Multicompartmental analysis suggests that the reduced hepatic bilirubin clearance is the result of a defect in both hepatic bilirubin uptake and conjugation. Twenty-one studies in a control group with anemia and/or hemolysis were indistinguishable from normal, indicating that neither of these factors was responsible for the abnormalities noted. These studies suggest that current diagnostic criteria for Gilbert's syndrome, which exclude patients with hemolysis, will result in an artificial distinction among patients with the same basic hepatic abnormality.

The fate of benzoic acid in various species.

1. The urinary excretion of orally administered [(14)C]benzoic acid in man and 20 other species of animal was examined. 2. At a dose of 50mg/kg, benzoic acid was excreted by the rodents (rat, mouse, guinea pig, golden hamster, steppe lemming and gerbil), the rabbit, the cat and the capuchin monkey almost entirely as hippuric acid (95-100% of 24h excretion). 3. In man at a dose of 1mg/kg and the rhesus monkey at 20mg/kg benzoic acid was excreted entirely as hippuric acid. 4. At 50mg/kg benzoic acid was excreted as hippuric acid to the extent of about 80% of the 24h excretion in the squirrel monkey, pig, dog, ferret, hedgehog and pigeon, the other 20% being found as benzoyl glucuronide and benzoic acid, the latter possibly arising by decomposition of the former. 5. On increasing the dose of benzoic acid to 200mg/kg in the ferret, the proportion of benzoyl glucuronide excreted increased and that of hippuric acid decreased. This did not occur in the rabbit, which excreted 200mg/kg almost entirely as hippuric acid. It appears that the hedgehog and ferret are like the dog in respect to their metabolism of benzoic acid. 6. The Indian fruit bat produced only traces of hippuric acid and possibly has a defect in the glycine conjugation of benzoic acid. The main metabolite in this animal (dose 50mg/kg) was benzoyl glucuronide. 7. The chicken, side-necked turtle and gecko converted benzoic acid mainly into ornithuric acid, but all three species also excreted smaller amounts of hippuric acid.

肝疾患の病態生理に関する研究

Using the technic of column chromatography, free and conjugated forms of BSP in serum were separated and studied on thirty-five cases of various liver diseases. Following results were obtained.1) As a cause of BSP retention in patients with chronic hepatitis and cirrhosis of the liver, it is due to the defects in hepatic uptake or conjugation or both.2) In case of obstructive jaundice, the conjugation of BSP is relatively intact, however, the secretory mechanism or excretory pathway for BSP is impaired.3) Patients with Dubin-Johnson's syndrome, increasing of BSP retention fourty-five minutes after intravenous administration and conjugated form of BSP in serum were recognized. As a result, it is reconfirmed that BSP retention in this syndrome is due to the regurgitation of conjugated BSP via microvilli to the blood.4) In two cases of Rotor's disease, BSP retention was considerably in high degree, however, increasing of BSP retention fourty-five minutes after intravenous administration could not be observed and conjugated BSP was only 1.0 to 1.2% in serum. Also, plasma disappearance rate of Indocyanine green (KICG) was remarkably low. With these findings, it is still difficult to explain or conclude the excretory mechanism of BSP in this disease at present.5) It is estimated as significant and helpful for clinical diagnosis as an aid to differentiate the dysfunction of liver parenchymal cell and obstructive jaundice by studying both percentage retention of BSP and ratio of free and conjugated BSP.

Familial Form of Benign Idiopathic Recurrent Cholestasis

SINCE 1959, several reports have described a condition characterized by intrahepatic obstructive jaundice occurring at frequent intervals in the absence of any identifiable etiological factor.^1-7The condition may be distinguished from the congenital idiopathic hyperbilirubinemias of Gilbert and Lereboullet⁸and of Crigler and Najjar⁹by the fact that the bilirubin is predominantly in the conjugated form and the urine is heavily loaded with bile during episodes of jaundice. The serum bilirubin concentration is elevated beyond the range encountered in other idiopathic hyperbilirubinemias without conjugation defects, and the serum alkaline phosphatase (SAPase) activity is invariably abnormal when the patient is jaundiced, and sometimes grossly so, in contrast to the normal or low values usually found in the syndromes of Dubin and Johnson¹⁰and of Rotor.¹¹Unlike the Rotor syndrome, the histological appearance of the liver during an episode of jaundice is abnormal, but the "lipochrome-like material"

Hereditary non-spherocytic hemolytic disease

Twenty patients with hereditary non-sphero-cytic hemolytic disease, with varying rates of hemolysis, are described. This familial disorder is characterized by the presence of an intra-corpuscular defect of the erythrocytes without definitive morphologic abnormalities. It is important to differentiate this disease from hereditary spherocytosis because splenectomy is of little or no benefit. When hemolysis is mild, constitutional hepatic dysfunction and posthepatic hyperbilirubinemia may be clinically indistinguishable from hereditary non-spherocytic hemolytic disease. Red cell survival studies are frequently required to establish the appropriate diagnosis. Our incidence of constitutional hepatic dysfunction was surprisingly low when these technics were employed. The nature of the red cell lesion in hereditary non-spherocytic disease is not known. Recent evidence supports the possibility of an enzymatic abnormality in at least some of the patients. Bilirubinemia, which is out of proportion to the severity of hemolysis, suggests a possible defect in bilirubin conjugation or transport in addition to the intrinsic red cell abnormality.

Constitutional Nonhemolytic Hyperbilirubinemia in the Rat: Defect of Bilirubin Conjugation

Summary1. Broken-cell preparations of liver and of kidney from rats with constitutional nonhemolytic hyperbilirubinemia failed to synthesize bilirubin or o-aminophenol glucuronides. 2. Inhibition of β-glucuronidase with potassium saccharate failed to influence conjugation of bilirubin in these animals. 3. The evidence presented suggests that in constitutional nonhemolytic hyperbilirubinemia in rats, glucuronyl transferase activity is absent or inhibited.