Multiple autopoly(ADP-ribosyl)ation of rat liver poly(ADP-ribose) synthetase. Mode of modification and properties of automodified synthetase.
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Biomedical subjects
Publications and source records attributed to K Ueda.
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The sera from patients with human Duchenne (X-linked) progressive muscular dystrophy contain elevated adenylate kinase (ATP: AMP phosphotransferase, EC 2.7.4.3) activities, in addition to their characteristically high creatine kinase (ATP; creatine N-phosphotransferase, EC 2.7.3.2) activities. By agarose gel electrophoresis of human Duchenne dystrophic serum, the presence of an apparently normal human serum adenylate kinase together with a variant species of adenylate kinase was detected. The latter enzyme species appeared, in its mobility, to be similar to that of the normal human liver-type adenylate kinase. The presence of this aberrant liver-type adenylate kinase could also be demonstrated by characteristic (for the liver type) inhibition patterns with P1,P5-di-(adenosine-5')pentaphosphate, 5,5'-dithiobis(2-nitrobenzoate) and phosphoenolpyruvate. On the other hand, by inhibition titrations with an anti-muscle-type adenylate kinase, hemolysates from the erythrocytes of several Duchenne and Becker's dystrophics were found to contain approx. 96% muscle-type adenylate kinase and their serum approx. 97% muscle-type adenylate kinase. These same patients contained approx. 89% M-M type creatine kinase in their serum (by inhibition against anti-human muscle-type creatine kinase) indicative of the presence also of M-B plus B-B type active isoenzymes. All of these data can best be explained by the presence of a variant or mutant adenylate kinase isoenzyme in the dystrophic serum. This isoenzyme appears to resemble the liver type in its inhibition patterns with P1,P5-di(adenosine-5')pentaphosphate, 5,5'-dithiobis(2-nitrobenzoate) and phosphoenolpyruvate, and in its heat stability (compare also the agarose gel electrophoresis pattern); but structurally, it is a muscle type, or derived from a muscle type, as shown immunologically by inhibition reactions with anti-muscle-type adenylate kinase. Whether this is a fetal-type isoenzyme of adenylate kinase will require further investigation.
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Poly(ADP-ribose) synthetase was identified as the main acceptor of this polymer produced in isolated nuclei of rat liver. When the nuclei were incubated with [32P]NAD at a limited concentration (2.4 microM) and for a brief period (10 s), a protein with Mr = 110,000 was predominantly poly(ADP-ribosyl)ated, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The modification of this protein increased upon longer incubations or at higher NAD concentrations, and induced a marked increase in the apparent molecular weight. A comparison with poly(ADP-ribose) synthetase (Mr = 110,000) of rat liver under various conditions suggested that the increase in the molecular weight of the acceptor resembled that of the synthetase undergoing multiple auto-poly(ADP-ribosyl)ation. This interpretation was further supported by the following observations: 1) [32P]poly(ADP-ribose) attached to the acceptor co-eluted with the synthetase activity from a hydroxyapatite column; 2) the [32P]poly(ADP-ribose).acceptor complex isolated on the column was converted to a very large complex by further incubation with NAD; and 3) a group of large poly(ADP-ribose).acceptor complexes were reduced to a single molecular species with Mr = 110,000 by extensive digestion with poly(ADP-ribose) glycohydrolase. These findings altogether suggested that poly(ADP-ribose) synthesized in isolated nuclei was principally bound to the synthetase itself.
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Terminals of ascending afferents in the telencephalon of the goldfish were examined by the Fink-Heimer method, after the unilateral transection of the peduncular region containing the forebrain bundles. The ascending projections from the more caudal regions of the brain were seen mainly on the ipsilateral side of the lesion. The ascending forebrain bundles gave widely distributed terminals throughout the area dorsalis of the telencephalon, especially in the area dorsalis telencephali pars centralis (Dc) and in the area dorsalis telencephali pars lateralis (DI). They also gave sparse terminals to the preoptic area (POA).
An acute variant of subacute sclerosing panencephalitis (SSPE) was described in a 5-year-old boy who showed rapid progression of coma within 14 days of right hemiplegia. He had measles at 3 years of age. The diagnosis of SSPE was based on the following findings: high anti-measles antibody titer in the serum and in the spinal fluid, periodic complex of EEG, and typical pathological changes of the brain. Treatment with transfer factor failed to improve the worsening clinical course. It is suggested that SSPE should be considered in the differential diagnosis of acute fulminating encephalitides or intracranial vascular lesions.
The following features of trichoepithelioma papulosum multiplex (TPM) were revealed by electron microscopy: 1. Proliferation of basaloid cells similar to that in basal cell epithelioma (BCE). 2. Abortive hair shafts and hair papillae. 3. Keratinous cysts surrounded by flat keratinocytes, the cytoplasm of which had small-sized keratohyalin and Odland's bodies. 4. Glycogen deposition near the nuclei, vacuoles filled with amorphous materials and lipid droplets in the cytoplasm of tumor cells. 5. Extracellular compartments, in which fibrous materials, cell fragments, and mucinous substance were found. 6. Melanocytes containing melanosomes in stage II, Langerhans cells involving Birbeck's granules, Merkel cells and other dendritic cells.
2 children with Down's syndrome showed severe anaemia, leucocytosis with blastic cells, thrombocytopenia and hepatosplenomegaly. Bone marrow aspirations were near-dry tap and marrow biopsy revealed primary myelofibrosis with myeloid metaplasia (MMM). Their course was short with a blood picture similar to that of leukaemia. They expired 2 months and 21/2 months after diagnosis, respectively. The cases were thought to represent an acute childhood variant of MMM. Cytogenetic study of circulating white cells by 24 h culture without phytophaemagglutinin stimulation revealed aneuploidy in both cases, the first case showing marked aneuploidy with a predominant karyotype of 50,XX,+8,+19,+19,+21 and the second case a mosaic of 47,XX,+G/48,XX+G,+G. The karyotype of phytohaemagglutinin stimulated lymphocytes was 47,XX,+G in both cases. These findings suggest that the abnormal karyotypes are those of circulating blastic cells which are abnormal clones of haematopoietic cells responsible for MMM. In Down's syndrome, MMM might not be so rare as reported.
1. The present study was intended to elucidate the role of temporal patterns of impulse discharges of the gustatory primary afferents in the coding of taste qualities by the use of simultaneous analyses of the across-neuron patterning (5) and the temporal patterning of impulses. 2. Impulse discharges of 43 rat chorda tympani fibers elicited by gustatory stimulation (0.1 M NaCl, 0.5 M sucrose, 0.01 N HCl, 0.02 M quinine hydrochloride, 0.3 M KCl, and 0.02 M saccharin sodium) were recorded. The temporal patterns of impulse discharges elicited by these stimuli were statistically analyzed both in an initial dynamic phase and a succeeding stationary phase of responses. In the dynamic phase, the time courses of firing frequency were studied; however, these were not clearly associated with the qualities of taste stimuli. In the stationary phase, the stochastic properties of impulse trains were studied regarding the impulse trains as a stochastic point process (30). In this study, interspike interval histograms (ISI histograms), joint interval histograms, serial correlograms, and autocorrelograms were computed. 3. In general, the distribution patterns of ISI histogram were not absolutely specific to the taste qualities. However, the gamma or the exponential distribution occurred most often with 0.1 M NaCl, and the bimodal or the skewed distribution was dominated with 0.5 M sucrose stimulation among the stimuli tested. The rhythmic discharges did not occur exclusively with the sweet taste stimulation, though they occurred more often with the sweet taste stimulation than with other taste stimulations. The joint interval histogram and the serial correlogram were used to examine the stochastic properties of impulse trains with particular reference to the time dependence in the impulse trains. Generally, the time dependence was not concerned with the taste qualities. 4. The chorda tympani fibers were classified into three types according to the magnitude of responses and the temporal patterns of impulse discharges. The neurons predominantly responsive to NaCl and unresponsive to sucrose were classified as type I neurons. The remaining neurons, which moderately responded to both NaCl and sucrose, were further categorized into type II neurons and type III neurons, depending on their temporal patterns of impulse discharge. The type II neurons tended to show the rhythmic or burstlike firing of impulses in response to more than one kind of taste stimuli. 5. The results showed that the taste quality was represented in the characteristic temporal patterning of impulses as well as in the across-neuron patterning of responses. The possible origin of the temporal discharge pattern and its significance in gustatory information processing were discussed on the basis of the neuron types described above.
Electrophysiologic studies using the His bundle electrogram (HBE) and histologic studies of serial sections of the conduction system were correlated in two groups of deceased patients. Group 1 consisted of five patients with chronic complete atrioventricular block (CAVB) who had narrow QRS complexes and AH block (block proximal to the His bundle deflection). Group 2 consisted of four patients with chronic CAVB who had wide QRS complexes and HV block (block distal to the His bundle deflection). In group 1, the sites of the main lesion were not located in the approaches to the atrioventricular (AV) node or the AV node, but were found in the penetrating portion of the His bundle in one patient and in the branching portion of the His bundle in three patients. In the remaining patient, the main site of block could not be demonstrated histologically in the AV conduction system, but marked fibrosis of the approaches to the sinoatrial node and surrounding atrial muscle was found. In all patients of group 2, the site of the main lesion was located in the bilateral bundle branches, and thus was compatible with so-called trifascicular block. This correlation study between the His bundle electrogram and histologic findings of the AV conduction system showed that in some cases, CAVB presenting as AH block on the HBE can be associated with a lesion in the branching portion of the His bundle (distal His), and that CAVB presenting as HV block on the HBE is associated with a bilateral lesion of the bundle branches.
The relationship between the concentrations of intermediate-density lipoprotein (IDL) and other lipoproteins and the extent of coronary artery disease (CAD) was studied in 182 consecutive patients evaluated by selective coronary cineangiography. On univariate analysis, the extent of CAD correlated significantly and positively with very low density lipoprotein (VLDL) cholesterol, IDL cholesterol and low-density lipoprotein (LDL) cholesterol, and negatively with high-density lipoprotein (HDL) cholesterol. Analysis of four subgroups divided by IDL cholesterol and LDL cholesterol levels indicated that moderately increased levels of IDL cholesterol were closely associated with a high frequency of CAD. Moreover, multi-variate regression analysis demonstrated that IDL cholesterol for men, LDL cholesterol for men and women and HDL cholesterol for men were significant variables of use in the final weighting procedure. IDL cholesterol was closely associated with cholesterol-rich VLDL. This study shows that IDL and cholesterol-rich VLDL combine to contribute to the development of CAD.
We studied biochemical genetics of low density lipoprotein (LDL) receptor mutations in fibroblasts from six homozygous and five heterozygous patients with familial hypercholesterolemia (FH). Three of six homozygotes are receptor-negative type and the other three homozygotes are receptor-defective type. In the cells from three receptor-negative homozygotes, the receptor binding, internalization, and degradation of (125)I-LDL were 0.5+/-0.3 ng/mg protein (mean+/-SEM), 14+/-8 and 8+/-6 ng/mg protein per 6 h (four normal cells; 44+/-3, 386+/-32, and 1,335+/-214 ng/mg protein per 6 h), respectively. In the cells from three receptor-defective homozygotes, the receptor binding, internalization, and degradation of (125)I-LDL were 6+/-2, 29+/-8, and 90+/-32 ng/mg protein per 6 h, respectively. In these six homozygotes, two pairs of siblings are included. Two siblings in the same family were classified as receptor-negative and two siblings in another family were classified as receptor-defective. The receptor-negative phenotypes and the receptor-defective phenotypes bred true in individual families. The cells from five heterozygotes showed approximately 46% of the normal activities of receptor.ML-236B, competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), completely inhibited the incorporation of [(14)C]acetate into digitonin-precipitable sterols in fibroblasts from normal subjects and heterozygous and homozygous patients with FH with the concentration of 0.5 mug/ml. However, at 0.05 mug/ml of ML-236B sterol synthesis in fibroblasts from homozygotes was not completely suppressed in contrast to normal and heterozygous cells. Moreover, after preincubation with 0.05 mug/ml of ML-236B for 24 h in medium containing lipoproteins, sterol synthesis in the cells from receptor-negative homozygote showed 75% of the initial activity compared with that of 25% without preincubation. In the cells from a normal subject and a heterozygote, sterol synthesis was inhibited even after preincubation. These results suggest that (a) the inhibitory effect of ML-236B is overcome in homozygote cells by their high intracellular levels of HMG-CoA reductase and (b) that a higher dose of ML-236B may be required to lower serum cholesterol levels in FH homozygotes than in heterozygotes.
Birth weights of 42 full-term patients with congenital rubella syndrome were analyzed. All of these infants were products of pregnancies in which the exact dates of the maternal first day of last menstrual period and of the time of onset of the mothers' rubella rash were known. The range of time of maternal rubella associated with low-birth-weight was in the gestational age interval from 16 to 100 days. Low-birth-weight may have a relationship with time of maternal rubella rather than with the type of defects, i.e., cataract, heart disease, and deafness.
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