Biological role of alcohol dehydrogenase in the tolerance of Drosophila melanogaster to aliphatic alochols: utilization of an ADH-null mutant

The toxicity of the first eight primary alcohols and of four secondary alcohols was compared in a wild-type strain (having active ADH) and an ADH-negative mutant. Differences between LC50 measured in the two strains allowed an evaluation of the biological activity of the enzyme. In vitro, ADH is mainly active on secondary alcohols, while in vivo its main role is the detoxification and metabolism of ethanol. These observations suggest that originally ADH was involved in unknown metabolic pathways and that its utilization in ethanol metabolism could be a recent event.     

Effects of exogenous hormones and glucose on plasma levels and hepatic metabolism of amino acids in the fetus and in the newborn rat

The present study examines the role of insulin, glucagon and cortisol in the regulation of gluconeogenesis from lactate and amino acids in fetal and newborn rats. Injection of glucagon in the full-term fetal rat caused a rise in glucose (and insulin) and a fall in blood levels of most individual amino acids, stimulated hepatic accumulation of 14C-amino isobutyric acid and 14C-cycloleucine and increased the conversion of 14C lactate, alanine and serine to glucose in vivo and in vitro (liver slices). Such changes were equivalent to the changes seen in 4 h old newborn rats. When glucagon was administered at birth, little difference was observed between control and treated animals in plasma amino acids and a smaller increment in conversion of 14C substrate to glucose occurred. By contrast, insulin injection at birth caused hypoglycemia, suppression of levels of certain amino acids and inhibition of conversion of 14C substrates into glucose. Glucose injection at birth caused elevated glycemia and plasma insulin and suppression of most amino acid levels and of conversion of 14C substrate into glucose. Cortisol injection at birth caused a marked, generalized by hyperaminoacidemia, a stimulation of glucagon secretion and of conversion of 14C substrates into glucose. These observations support the thesis that glucagon plays a major role in the induction of hepatic gluconeogenesis and that insulin acts as an antagonist hormone.     

Surgical significance of extrahepatic biliary tree anomalies

A patient with an anomalous insertion of the right hepatic duct into the cystic duct was noted during cholecystectomy and confirmed by operative cholangiography. This case and related anomalies of the bile ducts are of sufficient importance that, because of the technical difficulties and dangers incidental to their presence, no surgeon who operates on the gallbladder and bile ducts can afford to be unaware of their existence. Adequate exposure, careful dissection, and accurate knowledge of the regional anatomy plus a realization of the frequency and multiplicity of abnormalities of the extrahepatic biliary tree are requisites for safe biliary tract surgery. In addition, carefully performed operative cholangiography can be an indispensable aid in the clarification of anatomic variations. In case of recognized operative injury to the extrahepatic biliary tree, primary repair or biliary-intestinal anastomosis can usually be carried out with good results.     

4-aminobiphenyl, 2-naphthylamine, and analogs: analytical properties and trace analysis in five substrates

Methods for monitoring trace levels of 4-aminobiphenyl, 2-naphthylamine, and their hydrochloride salts in waste water, microbiological growth media, potable water, human urine, and mouse blood utilizing spectrophotofluorometry (SPF) are described. The salient elements of the methods are extraction of the residues as the free amine with benzene, rapid cleanup on an alumina column, and quantification of the free amine in methanol via SPF. Potable water solutions of the salts are diluted with 0.01 N aqueous HCL and quantified directly by SPF. Ancillary analytical information concerning gas chromatography of the free amines, partitioning properties of the compounds between solvent pairs, their solubility and stability in water, and thin-layer chromatographic data is presented. The compositions of various admixtures of 1- and 2-naphthylamine or their salts were determined by using SPF with calculations based on simultaneous equations.     

Subjective definitions of tension

To examine the type of proprioceptive information which subjects include in the definition of tension, 52 subjects were asked to indicate the location of where they felt tension while engaging in a simple motor task. Responses indicated that tendon stretch, muscle tension, and other cues are utilized in the subject's definition of tension.     

Energetics of triosephosphate isomerase: deuterium isotope effects in the enzyme-catalyzed reaction

The effect of isotopic substitution of the specifically labilized hydrogen in the substrates of triosephosphate isomerase on the steady-state rates of the enzyme-catalyzed reaction has been examined. The k cat value for the enzyme-catalyzed transformation of [1(R)-2H] dihydroxyacetone phosphate is 2.9 times smaller than that for the 1(R)-1H compound. Because of the rapid loss of 2H to solvent from the enzyme-enediol complex, this factor represents the full kinetic isotope effect of the proton abstraction step. The values of k cat and of Km for D-[2-2H]glyceraldehyde 3-phosphate are indistinguishable from those of the 2-1H material. This arises from the rapid loss of 2H from the enzyme-enediol intermediate, which results in 1H rather than 2H transfer in the rate-limiting step. The steady-state kinetic results reported in this paper qualitatively confirm and quantitatively extend the results from the previous papers on the variation of the free energy along the reaction path.     

Bronchopulmonary dysplasia: the pulmonary pathologic sequel of necrotizing bronchiolitis and pulmonary fibrosis

A light and electron microscopic study was carried out in 21 infants in whom the pathologic diagnosis of bronchopulmonary dysplasia had been made. All the infants except two had the respiratory distress syndrome at birth, and all 21 had been treated with respirator and oxygen therapy for various periods of time. The pathologic alterations observed in all the infants studied were primarily damage of the bronchial and bronchiolar ciliary apparatus and mucous membranes, severe necrotizing bronchiolitis, and marked bronchiolar and alveolar fibrosis. These changes were more pronounced in infants who survived the longest period of time. Such inflammatory and fibrotic changes are known to predispose to destruction of lung tissue, emphysema, and pulmonary hypertension. Six of these 21 infants developed symptoms and signs of cardiac atrial or ventricular stress, including cor pulmonale, prior to their demise. These infants were among those that survived the longest periods of time, had the longest exposure to supplemental oxygen, and showed histopathologically severe pulmonary fibrosis and emphysema.     

Location of nucleolar organizing regions on the chromosomes of the Syrian hamster (Mesocricetus auratus) and the Djungarian hamster (Phodopus sungorus)

Terminal chromosome associations ("satellite associations") in ASG-banded preparations have been used to determine the number and location of staellites in the Syrian hamster (Mesocricetus auratus) and the Djungarian hamster (Phodopus sungorus). Five pairs of satellites are found in the former and four in the latter. Nucleolar organizing regions (NORs) were visualized with the Ag-AS silver precipitation technique, and their number and position corresponded exactly with the number and position of satellites in Phodopus, where positive chromosome identification can be made in the absence of banding. Numerical agreement is exact in Mesocricetus as well, and the morphology of the silver-tagged NOR-bearing chromosomes strongly suggests that corrrespondence also occurs in this species.