Changes of enzyme activity in the rat liver at different age in circadian cycle

Most of the biological processes in the living organisms of both animals and man are known to be of rhythmical nature. Variability of enzymatic activity in circadian cycle depends on many factors among other on age, sexual maturity, diet as well as medication. The results obtained in our studies indicate, that the activity changes of acid phosphatase and ATP-ase Mg++ dependent in the liver of all the examined age groups were of 24 hour circadian rythm. As to the acid phosphatase activity the results of this experiments showed that in circadian cycle in all examined age groups there is only one peak of elevated activity. ATP-ase Mg++ dependent showed two activity peaks appearing at the same hour both in 30 and 60 days old animals. It should be noticed that the activities of ATP-ase Mg++ dependent in 100 day old animals were two times higher than in 30 and 60 days old rats.     

Unusual evolutionary conservation of 5S rRNA pseudogenes inAspergillus nidulans: Similarity of the DNA sequence associated with the pseudogenes with the mouse immunoglobulin switch region

Summary AllAspergillus nidulans 5S rRNA pseudogenes known so far are the result of integration of an approx. 0.2-kbp-long DNA sequence into the 5S rRNA genes. This sequence, called block C, is present in at least five copies in theA. nidulans genome and seems to be associated either with 5S rRNA genes or pseudogenes. In contrast to the 78% sequence conservation of the C-block in pseudogenes, the truncated 5 halves of the pseudogenes are very highly conserved (96.9–100%). We postulate that the 5S rRNA pseudogenes are still a subject of concerted evolution. The C-block sequence shows similarity to the switch region of the mouse heavy chain immunoglobulin gene. A characteristic motif GGGTGAG is repeated several times in both sequences; the sequence conservation is 63%.     

Molecular genetic analysis in the diagnosis of lymphoma in fine needle aspiration biopsies. II. Lymphomas versus nonlymphoid malignant tumors

The configurations of immunoglobulin genes and T-cell receptor beta chain genes were analyzed by Southern blotting in DNA derived from nonlymphoid malignant tumors and lymphomas. Gene rearrangements were not detected in any of the 35 cases of nonlymphoid malignant tumors. On the contrary, they were shown in all 14 cases of non-Hodgkin's lymphomas, 2 of 3 cases of Hodgkin's disease and 2 cases diagnosed as non-Hodgkin's lymphoma or angioimmunoblastic lymphadenopathy. The differentiation by light microscopy between lymphoma and nonlymphoid malignant tumors was a diagnostic problem in five cases; the molecular genetic analysis of DNA was contributory in all five diagnostically difficult aspirates. By gene rearrangement studies, the diagnosis of lymphoma was confirmed in two cases and nonlymphoid malignant tumors were accurately indicated in aspirates diagnosed finally as rhabdomyosarcoma (one case) and carcinoma (two cases).     

Contribution of midbody channels to embryogenesis in the mouse

Summary We have examined the persistence of midbody channels during the second, third, and fourth cleavage cycles of the mouse using immunofluorescence to map the distribution of midbody microtubule bundles in intact embryos. Electron microscopy showed these bundles to be a characteristic feature of midbodies throughout the interphase period. In recently-divided embryos at each cleavage stage the number of midbodies was half the number of blastomeres, and declined towards zero as the next cleavage approached. This indicated to us that the only midbodies present in each stage were those which had arisen in the immediately-preceding division. Of those blastomeres which were in mitosis at the time of fixation, less than 4% were connected via a midbody to another blastomere, demonstrating that persistence of midbodies beyond a single cleavage cycle is a rare event. We conclude that midbody channels in our embryos are likely to connect only pairs of sister blastomeres because midbodies do not persist through multiple cleavage cycles. Midbody channels cannot, therefore, be regarded as providing extensive cell coupling in advance of the onset of gap junctional communication.     

Autoradiographic studies on glucose utilization in individual zone of the rat thymus

Summary Wistar rats were injected intraperitoneally with 2-(¹⁴C)deoxyglucose and their thymuses were processed for thaw-mount autoradiography after 5, 10 or 35 min. Highest levels of radioactivity were demonstrated in the thymic medulla (5-fold higher than in the cortex). Scanning of autoradiograms for regional differences in grain densities indicated particularly intense glucose utilization in the cortico-medullary zone. Differences in glucose utilization between individual thymic zones seem to reflect differences in cellular composition, i. e., ratio of stroma cells to thymocytes.Dedicated to Professor Dr. T.H. Schiebler on the occasion of his 65th birthday     

The influence of peripheral nerve graft's predegeneration stage on the regrowth of hippocampal injured neurites and concomitant changes in submicrosomal fraction proteins of grafts.

The present work has a twofold aim: 1. To ascertain whether the stimulative influence of peripheral nerve grafts on injured hippocampal neurons depends on the time lapse after transection and; 2. To examine whether the mentioned effect runs parallel to the time-dependent changes of proteins contents and composition in the submicrosomal fraction from transected rat sciatic nerves. Fluorescence microscope examination revealed that FITC-HRP labeled cells extending their neurites into the implanted peripheral nerve segments were particularly numerous among the hippocampal neurons when 7- and 35-day-old predegenegated distal stumps were used as grafts. Discontinuous SDS-slab polyacrylamide gel electrophoresis of submicrosomal fraction proteins obtained from distal stumps of rat sciatic nerves was performed at the 7, 14, 21 and 35 days after transection. Among the obtained protein fractions the most interesting seem to be the ones of 47 and 54 kDa, which reached maximal levels at the 7th day and the 50 kDa fraction with a maximum at the 35th experimental day. It is possible that the growth promoting power of the employed grafts depends on the presence of proper proteins.