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Biomedical subjects

L Bachner

Publications and source records attributed to L Bachner.

29 records · Page 2Linked to original sources
PubMed1986

In vivo developmental modifications of the expression of genes encoding muscle-specific enzymes in rat.

cDNA clones for rat muscle-type creatine kinase and glycogen phosphorylase and aldolase A were isolated from a rat muscle cDNA library. An additional clone recognizing an unidentified 2.7-kilobase pair mRNA species was also isolated. These cDNA clones were used as probes to investigate the expression of the corresponding mRNAs during muscle development. Two aldolase A mRNA species were detected, one of 1650 bases expressed in non-muscle tissues, fetal muscle, and adult slow-twitch muscle, the other of 1550 bases was highly specific of adult fast-twitch skeletal muscle differentiation. These aldolase A mRNAs were shown by primer extension to differ by their 5' ends. The accumulation of muscle-type phosphorylase and creatine kinase and muscle-specific aldolase A mRNA accumulation during muscle development seems to be a coordinate process occurring progressively from the 17th day of intrauterine life up to the 30th day after birth. In contrast, the 2.7-kilobase pair RNA species is maximally expressed at the 1st week after birth as is the neonatal form of myosin heavy chain mRNA.

Aging↗
PubMed1985

Modifications of the expression of liver-specific and non-specific messenger RNAs during azo-dye hepatocarcinogenesis.

The expression of specific and non-specific rat liver messenger RNAs has been studied during 3'-methyl-4-(dimethylamino)azobenzene (3'-MeDAB) carcinogenesis, using cDNA probes complementary to mRNAs encoding aldolase A and B, L-type pyruvate kinase, albumin, alpha-fetoprotein, transferrin and an unidentified 2.7 X 10(3)-base mRNA. mRNAs specific for undifferentiated cells, such as those encoding aldolase A and the unidentified 2.7 X 10(3)-base species were re-expressed very early, being easily detectable at the 1st week of 3'-MeDAB treatment. They reached a maximum of expression at the 4th week. Simultaneously the levels of aldolase B and L-type pyruvate kinase mRNAs dramatically decreased as compared to controls, but remained responsive to induction by a high-carbohydrate diet. Albumin and transferrin mRNA levels were only slightly modified in the course of the carcinogenic diet. At the terminal stage of hepatocarcinogenesis, i.e. in malignant hepatoma cells, expression and inducibility of aldolase B and L-type pyruvate kinase mRNAs were similar to those in normal adult rats while mRNAs specific for undifferentiated or foetal stages were also synthesized. The very early changes in gene expression for aldolases A and B, L-type pyruvate kinase and the 2.7 X 10(3)-base mRNA species could indicate that carcinogenic diet modifies gene control mechanisms long before inducing hepatoma.

Animals↗
PubMed1979

An improved and easy technique for polyamine determination in biological samples. Application to cell-free system from hypertrophied rat heart.

An accurate, improved cation-exchange chromatographic method using o-phthalaldehyde and ultraviolet detection at 280 nm for the determination of free polyamines (putrescine, spermidine, spermine) has been developed. Different samples, such as the 105,000 g supernatant of reticulocyte or heart muscle, and KCl ribosomal wash containing initiation factors, can be analysed. The minor modification of reagents results in a good precision and sensitivity, which is demonstrated by a relative standard deviation of 5--9% and recoveries of 98%. This technique is of particular interest because it allows polyamine determination in biological samples with high concentrations of salt.

Animals↗
PubMed1977

Increase of protein synthesis in cell-free system prepared from hypertrophied rat heart during L-triiodothyronine treatment.

During development of rat heart hypertrophy induced by repeated injections of triiodothyronine (T3), cell-free protein synthesis activities of heart post-ribosomal supernatant and of heart polysomes have been measured separately. This was done by complementation respectively with polysomes and post-ribosomal supernatants of adult and newborn rat heart, and of rabbit reticulocytes. In the presence of polysomes of either rat heart or reticulocytes, protein synthesis activity of the supernatant was maximum between the 3rd and the 8th day of treatment. Protein synthesis in the presence of polysomes from triiodothyronine treated rat hearts and of supernatants of both origins was maximum between the 11th and the 15th day.

Animals↗
PubMedDate not supplied

Induction by 3, 5, 3' L-triiodothyronine of L-ornithine decarboxylase in rat heart muscle.

Injection of 3,5,3' L-triiodothyronine (15 micrograms/100 g) induces a biphasic enhancement of rat heart ornithine decarboxylase (EC. 4.1.17) activity after 4 and 21 hours. This induction is observed after each daily injection, but to a lesser extent. The properties of partially purified basal enzyme and induced enzyme, at 21h, after single injections have been compared. 1) Affinity for ornithine is the same for both enzymes, but affinity for pyridoxal-phosphate is 40-fold higher for the induced one. 2) Thermostability studies suggest that basal and induced enzymes have different conformations. 3) The two enzymes have similar immuno-reactivity. 4) The comparisons of the time-dependent activity curve after injection and of the antigen/activity ratio suggests that triiodothyronine induces the synthesis of new molecules of enzymes and that an inhibition of the enzyme activity also occurs which explains the biphasic induction.

Animals↗