Arginylation, surface hydrophobicity and degradation of cytosol proteins from rat hepatocytes.
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Animals↗
Biomedical subjects
G Adam
Publications and source records attributed to G Adam.
[Hyaline articular cartilage in MR tomography of the knee joint at 1.5 T].
MRI is a new method for imaging the knee joint. There is still some uncertainty regarding the extent and the signal from hyaline articular cartilage. MRI images were therefore compared with anatomical and histological preparations of the knee joint and the difference between MRI and the anatomical sections have been determined. It was shown that demonstration of hyaline cartilage was obscured by an artifact. Further investigations are required to determine the cause of this artifact and to achieve accurate imaging of hyaline cartilage by MRI.
Cadaver↗
Surface hydrophobicity, arginylation and degradation of cytosol proteins from rat hepatocytes.
In vitro 14C-prelabelled cytosol proteins from rat hepatocytes were incubated with [3H]arginyl-tRNA in ATP-Tris-Mg-KCl-dithioerithrol medium and arginyltransferase, subsequently treated with RNase A, and the double-labelled proteins were isolated by gel filtration. The affinity of these [3H]arginylated-14C-labelled cytosol proteins to hydrophobic surfaces was investigated with octyl-Sepharose, phenyl-Sepharose and with FPLC on phenyl-Superose (HR 5/5). All 3H/14C-ratios of the proteins in the column fractions show that arginylated proteins bind preferentially to the hydrophobic matrices: the fractions eluted first show low 3H/14C-ratios, and after addition of ethylene glycol and especially of Tween 80 the 3H/14C-ratios markedly increase. Furthermore, these arginylated proteins aggregate preferentially after incubation of the cytosol proteins for 2 h at 37 degrees C and are more rapidly degraded by endopeptidases.
Animals↗
[The patella-nail syndrome. Study of 2 families].
The radiological and clinical features of two families with a nail-patella syndrome are described. Our findings emphasize the varying expressivity of the syndrome, which has an autosomal dominant mode of inheritance and a penetrance of 100%. It is important for the radiologist to be aware of the syndrome's stigmata so that renal failure can be detected as early as possible after the diagnosis of skeletal dysplasia.
Adolescent↗
[Mercury absorption during the use of Grob crusting in the treatment of burns--an experimental animal study].
The absorption of mercury was investigated after three phase crusting by Grob on a second-degree scald burn of 10 to 15% of the body surface in rats. Mercury was provable histologically in kidney and liver already after 3 days. A clear cumulation was shown especially in kidney and liver in the further course. The abundant renal tubuli cytoclasis are to be seen in connection with mercury absorption and storage. Further depositions were provable in the subcutaneous fibroblasts of the thermically damaged skin as well as in the spleen and rarely in the brain. The investigations demonstrate that there occurs a mercury absorption. Against the employment of the formation of crust by Grob must be warned specially in burns of large planes.
Absorption↗
Level of ribosomal RNA required for stimulation from quiescence increases during cellular aging in vitro of mammalian fibroblasts.
We have investigated the relation between cell size in terms of cellular ribosomal RNA (rRNA) content and proliferation of diploid human and rat embryo fibroblasts during their aging in vitro. During phase III of the proliferative lifespan in vitro, cellular rRNA content increases by a factor of nearly 3. For very different regimes of stimulation of quiescent cells, a strict correlation was observed, between the proportion of cells stimulated and cellular rRNA content, resembling a steep threshold curve. During aging in vitro, these characteristic curves exhibit an essentially parallel shift to higher values of cellular rRNA content (to higher 'thresholds'). Upon establishment as a permanent cell line, the relation between proliferation stimulation and cellular rRNA ceases to change with further subculturing. It is suggested that the essence of transformation of fibroblasts with a myc-type of oncogenes is a reduction and stabilizing of the critical rRNA content required for proliferation.
Animals↗
Lectins as probes for the assay of rhabdovirus infections in plants.
Thirteen different, biotinylated plant lectins were tested for their ability to recognize specifically the glycoproteins of the two different plant rhabdoviruses potato yellow dwarf virus and eggplant mottled dwarf virus. All viruses were propagated on the same plant host species, Nicotiana rustica L. The lectin-binding to the viral proteins was tested after electrophoretic separation and transfer to nitrocellulose membranes. Besides purified virus also partially pure virus preparations were used for the tests, in order to determine the specificity. The lectins had been selected for specificities to either one of the following monosaccharides: mannose, glucose, galactose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine and fucose. In the test panel of thirteen lectins, seven were found to react with the viral glycoproteins. Among these, four (LCA, VFA, PSA, Con A) belonged to the mannosyl- or glycosyl-specific group. However, these four lectins reacted also with other host proteins when partially pure virus preparations were used as samples. The other three lectins (GSA2b, STA, WGA) were specific for N-acetyl-D-glucosamine and detected almost exclusively the viral glycoproteins. Two of these lectins, STA and WGA, were extremely suitable for virus-specific assays, since they did not react with glycoproteins in healthy controls that were identical or comparable in their electrophoretic mobility with the rhabdovirus glycoproteins. No binding to viral glycoproteins was observed with galactose-, N-acetyl-galactosamine- and fucose-specific lectins. The assay for rhabdovirus glycoproteins in plants with the lectins was approximately 8-16 times less sensitive than with virus-specific antibodies.
Glycoproteins↗
[Report from Venezuela--use of the official table of food composition at present].
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Diet↗
An automated direct-injection HPLC-method for the electrochemical/fluorimetric quantitation of monoamines and related compounds optimized for the screening of large numbers of animals.
An automated, highly stable HPLC system is described allowing the quantitation of monoamines and related compounds with virtually online data processing and statistical evaluation of the mean values of various differently treated groups of animals. The system is highly suited to the screening of drugs involving large numbers of samples. To ensure long-term, uninterrupted performance, two robust chromatographic systems were developed optimized to separate neighboring peaks as widely as possible. This was achieved by using mobile phases of relatively low pH to retard acidic compounds, and optimal concentrations of the ion-pairing reagent to manipulate the retention times of amines on the RP-18 column, resulting also in clearcut separations from the solvent/tissue peak. Direct injection of deproteinized tissue samples, requiring no clean up procedures is used. One faster system allows measurement of the main biogenic amines, metabolites and TRP, whereas another system allows the simultaneous quantitation of DOPA, 5HTP, NA, MOPEG, NMN, A, MN, VMA, DA, 3MT, DOPAC, HVA, 5HT, 5HIAA and TYR. By pretreatment of animals with a decarboxylase inhibitor the latter system offers the possibility of detecting drug effects in the same animal on either dopamine and serotonin turnover or noradrenaline and serotonin turnover, depending on the brain area chosen. The system described has been running for over a year without major disturbance and with minimal technician attendance.
Animals↗
Cellular compartmentation of calcium in mouse fibroblasts in vitro depends on cell density and transformation.
Cellular compartmentation of Ca has been investigated by kinetic analysis of 45Ca efflux from preloaded cells at various states of cell density-dependent proliferation of normal (3T3) and transformed (3T6 and SV40-3T3) mouse cells. Three pools of exchangeable calcium were separated on the basis of their differing exchange kinetics. For each of the cell lines tested, all three compartments decrease with cell density. Significant differences between normal and transformed cells are observed upon quiescence of the normal cells, where the slowly exchanging compartment of normal cells gradually increases, whereas that of the transformed cells continues to decrease (with increasing cell density). Free cytoplasmic Ca2+ concentration as determined by the Quin 2 method, was found to be significantly higher in transformed cells than in normal cells. These results indicate significant differences in Ca homeostasis between normal and transformed cells.
Animals↗
Placebo controlled double-blind randomised cross-over trial of atenolol, hydrochlorothiazide and amiloride, and the combination (Kalten) in patients over 60 years of age.
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Aged↗
[Sudden infant death. Postmortem flow measurements in the large vessels of the neck for the demonstration of posture-dependent cerebral hypoxemia].
The concept of position-dependent cerebral hypoxaemia as a mechanical cause of sudden death in infants is based on the possibility of flow impairment in the large neck vessels (carotid and vertebral arteries) on marked rotation and (or) flexion of head and neck. To test this hypothesis systematic flow measurements were performed post-mortem with 21 different angles of head and neck in 16 infants who had died suddenly. The angles chosen were those taken especially during sleep with the infant in a prone position. The measurements demonstrated flow impairment, especially as a result of mechanical narrowing of both vertebral arteries. On the other hand, the range of variation in the internal carotid artery was marked and individual circumstances could not be estimated. There was no certain connection between flow impairment in the vertebral artery and possible increase in the carotid artery. The least dangerous extreme movement for an infant is dorsal flexion of the neck with reclining of the head, a favoured position of many infants. Particularly dangerous is flexion combined with rotation. Judged by the number of complete flow stoppages in the vertebral and carotid arteries, the danger is greatest with rotation in dorsal flexion. Since the dangers of supine position have been known for a long time, lateral position is urgently recommended as the sleeping position in infants.
Carotid Arteries↗
Interrelation between cellular rRNA content and regulation of the cell cycle of normal and transformed mouse cell lines.
The relation between cellular rRNA content, as a measure of cell size, and the regulation of the cell cycle has been investigated for swiss 3T3 and the spontaneously transformed swiss 3T6 cell line. It is shown that the characteristic of percent of quiescent cells stimulated into the cell cycle versus cellular rRNA content is basically different for 3T3 and 3T6 cells: 3T3 cells do not enter the cell cycle below a certain threshold of cellular rRNA content, whereas 3T6 cells start proliferation without a substantial increase of rRNA. These data are interpreted as consistent with transformation of 3T6 cells being in essence their uncoupling from the requirement of normal cells of passing over a threshold of cellular rRNA content (cell size) before initiating DNA-replication.
Animals↗
Selective effects by valinomycin on cytotoxicity and cell cycle arrest of transformed versus nontransformed rodent fibroblasts in vitro.
The effect of submicromolar concentrations of the K+ ionophore valinomycin on proliferation, viability, distribution of cell population over phases of the cell cycle, and cellular adenosine triphosphate content of different permanent rodent cell lines in vitro was investigated. Valinomycin inhibits proliferation of all cell lines tested with a saturating effect at about 20 to 100 nM. The effect of valinomycin on nontransformed 3T3 mouse and Rat-1 cells is nontoxic, whereas it acts with increasing toxicity on the transformed cells in the order 3T6 mouse, polyoma-3T3 mouse, temperature-sensitively Rous sarcoma virus-transformed Rat-1 at permissive temperature, and SV40-3T3 cells. According to these and some other criteria, the essential action of valinomycin appears to be to impose on the cells at low growth densities a state of limiting growth condition which normally is encountered only at high cell densities and/or low serum concentration. Nontransformed cells are proliferation arrested by valinomycin essentially in the G1 phase of the cell cycle, whereas all transformed cells under this condition are not arrested selectively in G1. In all cell lines tested (3T3, 3T6, and SV40-3T3), cellular adenosine triphosphate content is decreased by about 33% upon treatment with 20 nM valinomycin. Evidence is presented for a mitochondrial site of action of valinomycin.
Adenosine Triphosphate↗
Calcium compartments and fluxes are affected by the src gene product of Rat-1 cells transformed by temperature-sensitive Rous sarcoma virus.
Total cellular calcium content (determined by atomic absorption spectrometry) of Rat-1 cells transformed by temperature-sensitive Rous sarcoma virus decreases with cell density, but is found not significantly different at permissive and at non-permissive temperature. Kinetic analysis of 45Ca efflux from preloaded cells exhibits three separable pools of exchangeable calcium. The ratio of pool size of the fast-exchanging Ca-compartment (bound to cell surface) to pool size of the intermediate Ca-compartment (cytoplasmic) was found to decrease from 2.5 to 1.3 upon shift from non-permissive to permissive temperature. The slowly exchanging Ca-pool (presumably mitochondrial) did not change significantly upon temperature shift. These and further data demonstrate a close correlation between distribution of cellular Ca among different cellular compartments and characteristics of cellular proliferation, both attributable to the function(s) of a single oncogene.
Animals↗
Interfacial properties of hydrophilic surfaces of phospholipid films as determined by the method of contact angles. Comparison with cell surfaces.
Hydrophilic films of phospholipids were deposited onto plastic substrates (surface-treated for cell cultures) and shown to adhere sufficiently for measuring their interfacial properties by the method of contact angles. Both by absolute magnitude and by their dependence on temperature, the interfacial properties of these phospholipid films were indistinguishable from those determined for black lipid bilayer membranes with a different method by other authors. According to both their vesicular micromorphology and water permeability, the surface films can be interpreted to consist essentially of multibilayer vesicles with the hydrophilic groups facing outward. Treatment of these films with cell-culture medium containing calf serum results in changes of interfacial properties that are very similar to those effected on virus-transformed 3T3 cells (earlier work). These interfacial effects may be attributed essentially to serum proteins (such as albumin) adsorbing to phospholipid or cellular surfaces. The interfacial properties of nontransformed 3T3 cells are much less affected by serum treatment (earlier work), which correlates closely with their higher serum requirement for proliferation. Comparison of these results with those on the interfacial effects of serum on phospholipid films suggests that at least part of the proliferation-stimulating effect of serum is mediated by changes of interfacial properties of cell membranes upon adsorption of serum proteins such as albumin. Treatment of phospholipid films with concanavalin A, an inhibitor of cell proliferation, does not result in effects on their interfacial properties correlating with those on cellular membranes. This confirms previous suggestions that the latter depends on specific binding of concanavalin A to specific carbohydrates on the cell membrane.
Concanavalin A↗
Cellular content of ribosomal RNA in relation to the progression and competence signals governing proliferation of 3T3 and SV40-3T3 cells.
The method for differential fluorescence staining of cellular RNA and DNA by acridine orange (AO) was optimized for 3T3 and SV40-3T3 cells. Cellular contents of DNA and of ribosomal RNA (rRNA) were determined by dual-channel flow cytometry during cell-density-dependent proliferation and after stimulation of quiescent cells. With increasing density of 3T3 cells, cellular content of rRNA decreases by about 60%, whereas SV40-3T3 cells do not exhibit a significant dependence of rRNA content on cell density. 3T3 cells stimulated early after becoming quiescent resume reaccumulation of rRNA after a delay of only 4 h, whereas cells maintained at quiescence for several days exhibit a delay of about 12 h before a significant rise of rRNA is observed. The extent of rise of cellular rRNA content after different regimens of stimulation of quiescent 3T3 cells does not correlate well with the fraction of cells entering the cell cycle. These and other reported instances of discordance between rRNA content and stimulation into the cell cycle are resolved by showing that of the two signals governing entry into the cell cycle only the progression signal, but not the competence signal is associated with reaccumulation of cellular rRNA. The present results are consistent with the progression function being in essence the achievement of a threshold number of ribosomes per cell, which in conjunction with the competence signal is sufficient for initiation of the cell cycle.
Animals↗
[Operation-induced iatrogenic lesions of the colon and rectum--diagnostic and therapeutic principles and legal insurance aspects].
The slightest suspicion of an iatrogenic lesion requires immediate diagnosis. A complete perforation of the rectal or colonic wall has to be treated surgically in every case.
Adult↗