Beta-2 adrenergic receptors are not only for circulating catecholamines in ventricular muscles of carp heart (Cyprinus carpio)

Whether beta-2 adrenergic receptors are only for the circulating catecholamines in isolated ventricular muscles of carp heart was studied. Isoproterenol, epinephrine and norepinephrine had concentration dependent positive inotropic effects. The ED50 values for isoproterenol, epinephrine and norepinephrine were 6.23 +/- 1.9, 87.3 +/- 27.3 and 4500 +/- 580 nM, respectively. Phentolamine did not alter the inotropic effects. Tyramine increases the force of contraction and this action was completely blocked by propranolol and reserpine, but not by atenolol. Norepinephrine levels, in comparison with those of epinephrine, were similar in plasma and higher in ventricular muscles. However, the norepinephrine levels in ventricular muscles of carp heart were markedly lower than those in ventricular muscles of rat heart. These results suggest that ventricular muscles of carp heart contain adrenergic neurons, and that a catecholamine released from the nerve terminals, presumably epinephrine, may stimulate beta-2 adrenergic receptors.     

Micronucleus test with 2-acetylaminofluorene by intraperitoneal injection and oral administration

The effect of route of administration on the outcome of the mouse micronucleus test was evaluated in 2 laboratories by administering 2-acetylaminofluorene (2-AAF) by intraperitoneal injection (i.p.) and oral gavage (p.o.) to 2 mouse strains, MS/Ae and CD-1. On the basis of a small-scale acute toxicity study and a pilot micronucleus test, the full-scale experiment was performed with a 24-h sampling time at doses ranging from 75 to 600 mg/kg by both routes. The results indicated that 2-AAF induced micronucleated polychromatic erythrocytes (MNPCEs) at all doses tested by both routes. In the MS/Ae strain, higher doses were required by p.o. than by i.p. to reach a similar level of MNPCE incidence. On the other hand, similar responses were recorded by both administration routes with CD-1 mice. Since the LD50 for the p.o. route was higher than that for the i.p. route in both strains, the route-related difference with MS/Ae mice became small when the comparison between i.p. and p.o. was made on the basis of the LD50. Thus both i.p. and p.o. routes are acceptable in the micronucleus test of this chemical.     

Oscillation in the Growth Rate and a Shortening of the Lag Time for IAA Response by Cotyledons, Gibberellic Acid and Sucrose in Bean Hypocotyls

Oscillation in the growth rate as well the lag time for an IAAresponse in bean (Phaseolus vulgaris) hypocotyls were studiedwith a displacement transducer. The growing zone of the hypocotylshowed continuous oscillation in the growth rates for intactseedlings, hypocotyl explants with or without cotyledons, andexplants submerged in water. The lag time for the IAA response was shortened by the presenceof cotyledon tissues as well as by preliminary treatment withgibberellic acid and sucrose. When IAA first was applied tothe basal cut surface then to the upper cut surface of the hypocotylexplant, two growth responses with distinct lag periods werefound. The difference in the passage of auxin due to the directionof transport in the hypocotyl is discussed. (Received February 9, 1983; Accepted August 9, 1983)     

Purification and characterization of bovine dental sac collagenase

1. Active type collagenase was purified as much as 140-fold from the explant medium of bovine dental sacs and showed a single band on disc gel electrophoresis. Purified collagenase cleaved native collagen at only one locus under physiological conditions, but hydrolyzed neither gelatin nor alpha-casein. The optimal pH was about 7.8. 2. The molecular weight of active type enzyme was 35,000 by gel filtration and 34,000 by gel electrophoresis. The activation of latent type of collagenase resulted in the reduction of molecular weight from 45,000 to 38,000 by gel filtration. 3. A small but detectable amount of collagenase was directly extracted from frozen and thawed bovine dental sacs. In explant media of frozen and thawed tissue and fresh tissue with actinomycin D, some activity was detected for the first 2 days, but essentially no collagenase activity was detected in the explant medium after day 3. 4. The latent type collagenase was activated by trypsin, 4-aminophenylmercuric acetate (4-APMA), thiocyanate and deoxycholate (DOC). DOC showed irreversible dissociation of latent type enzyme in similar fashion to that exerted by 4-APMA. 5. The purified collagenase was inhibited by bovine serum, EDTA, o-phenanthroline, cysteine and dithiothreitol.     

KIM-1 mediates fatty acid uptake by renal tubular cells to promote progressive diabetic kidney disease

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Metabolic Associated Fatty Liver Disease Increases the Risk of Systemic Complications and Mortality. A Meta-Analysis and Systematic Review of 12 620 736 Individuals

ObjectiveThe recent introduction of the term metabolic associated fatty liver disease (MAFLD) sought to reclassify nonalcoholic fatty liver disease (NAFLD). MAFLD is thought to improve the encapsulation of metabolic dysregulation. However, recent evidence has found significant differences between MAFLD and NAFLD, and prevailing knowledge has largely arisen from studies on NAFLD. Hence, we conducted a meta-analysis and systematic review of the outcomes associated with MAFLD.MethodsMEDLINE and Embase databases were searched for articles relating to outcomes in MAFLD. Analysis was conducted in random effects with hazard ratios (HRs) to account for longitudinal risk assessment of mortality and systemic complications.ResultsA total of 554 articles were identified, of which 17 articles were included. MAFLD resulted in an increase in the overall mortality (HR, 1.24; confidence interval [CI], 1.13-1.34), cancer-related mortality (HR, 1.27; CI, 1.01-1.54), and cardiovascular disease mortality (HR, 1.28, 1.03-1.53; P = .04) compared with non-MAFLD. MAFLD also increases the risk of cardiovascular events (HR, 1.49; CI, 1.34-1.64; P < .01), stroke (HR, 1.55; CI, 1.37-1.73; P < .01), and chronic kidney disease (HR, 1.53; CI, 1.38-1.68). The presence of MAFLD was also associated with an increased risk of heart failure, obstructive sleep apnea, and malignancy.ConclusionMAFLD can significantly elevate the risk of systemic diseases and mortality. The care of MAFLD thus requires interdisciplinary collaboration, and future clinical trials conducted on MAFLD should aim to reduce the incidence of end-organ damage aside from improving liver histology.