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G Magni

Publications and source records attributed to G Magni.

At least 73 records · Page 4Linked to original sources
PubMed1992

Nuclear matrix-associated NMN adenylyltransferase activity in human placenta.

This paper presents data about the presence of the NMN adenylyltransferase at the nuclear matrix level of human placenta nuclei. It was found that 40-45% of the activity (depending on the extraction procedure) referred to the total nuclear NMN adenylyltransferase was tightly associated with this subnuclear compartment. The matrices purified by two different procedures exhibited DNA, RNA and protein contents comparable with those described in literature. Extensive digestion of human placenta nuclei with DNase I was not able to solubilize the NMN adenylyltransferase activity. Therefore, the data we present are consistent with the conclusion that a part of the total nuclear NMN adenylyltransferase is associated with the nuclear matrix.

Cell Fractionation↗
PubMed1992

NAD biosynthesis in human placenta: purification and characterization of homogeneous NMN adenylyltransferase.

Nicotinamide mononucleotide (NMN) adenylyltransferase has been purified to homogeneity from human placenta. The purification procedure consists of several chromatographic steps, including dye-ligand, adsorption, and hydrophobic interaction chromatography. The final enzyme preparation is homogeneous as judged by a single silver stainable band on both nondenaturating and denaturating polyacrylamide gels. The native enzyme shows a molecular weight of about 132,000, as determined by gel filtration on a Superose 12 HR 10/30 fast protein liquid chromatography column. The protein possesses a quaternary structure and is composed of four apparently identical M(r) 33,000 subunits. Isoelectrofocusing experiments give multiple pI values ranging from pH 4.7 to 6.6. Optimum pH study shows a plateau extending from pH 6.0 to pH 9.0. Km values for NMN, ATP, NAD+, and PPi are 38, 23, 67, and 125 microM, respectively. Kinetic analysis reveals a behavior consistent with an ordered sequential Bi-Bi mechanism. Among several metabolites tested only ADP-ribose and beta-NMNH were found to significantly inhibit the enzyme activity.

Amino Acids↗
PubMed1992

Limitations of the electrocardiographic diagnosis of left ventricular hypertrophy: the influence of left anterior hemiblock and right bundle branch block.

We analysed the performance of the electrocardiogram in diagnosing left ventricular hypertrophy in 70 patients with isolated left anterior hemiblock and in 75 patients with right bundle branch block, either isolated (44 cases) or associated (31 cases) with left anterior hemiblock. Left ventricular hypertrophy defined as an echocardiographically determined left ventricular mass greater than 261 g in men and 172 g in women or left ventricular mass index greater than 125 g/m2 in men and 112 g/m2 in women was present in 48 subjects (57%) with isolated left anterior hemiblock and 33 subjects (44%) with right bundle branch block. In patients with isolated left anterior hemiblock the best results were obtained using the SV1 or SV2 + (RV6 + SV6) greater than 25 mm with 74% in sensitivity and 67% in specificity; the criterion SIII + (R + S) maximal in a precordial lead greater than or equal to 30 mm showed a sensitivity of 74% but a specificity of 47%. In the whole group of patients with right bundle branch block none of the criteria nor combination of criteria achieved an acceptable performance (sensitivities ranged from 17% to 41% and specificities ranged from 54% to 85%). When these patients were divided according to the presence or absence of concomitant left anterior hemiblock the electrocardiographic indexes mostly showed, in comparison to whole group, higher values in sensitivity and lower values in specificity in right bundle branch block plus left anterior hemiblock and an opposite behaviour in isolated right bundle branch block.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Chronic abdominal pain and depression. Epidemiologic findings in the United States. Hispanic Health and Nutrition Examination Survey.

We report data on abdominal pain and depression from a survey of Hispanic Americans by the United States National Center for Health Statistics. The point prevalence rates of chronic abdominal pain were 4.6% in Mexican Americans and 5.8% in Cuban Americans in a total of 4175 subjects. The rate was 8.3% among 1323 Puerto Ricans. In 53% the abdominal pain came in waves. Using the Depression scale of the Center for Epidemiologic Studies (CES-D), 18.7% of Mexican and Cuban Americans with pain were found to be depressed to an extent likely to require intervention, and 40.8% of Puerto Ricans were so affected. The Diagnostic Interview Schedule (DIS) gave more conservative figures for major depression in terms of DSM-III, viz., 6.8% for Mexican and Cuban Americans with chronic pain, and 12.6% for Puerto Ricans with chronic pain. Logistic regression analyses demonstrated links between depression and female sex, the single state, low education and income, and chronic abdominal pain. The most consistent relationships for depression were with chronic pain, female sex and the single state. The results confirm the strong relationships between chronic pain, mood and female gender, and other socio-demographic variables.

Abdominal Pain↗
PubMed1992

Pharmacodynamics of venlafaxine evaluated by EEG brain mapping, psychometry and psychophysiology.

1. In a double-blind, placebo-controlled study the effects of venlafaxine--a novel nontricyclic compound inhibiting neuronal uptake of serotonin, noradrenaline and to a lesser extent dopamine--were investigated utilizing EEG brain mapping, psychometric and psychophysiological measures. 2. Sixteen healthy volunteers (eight males, eight females) aged 21-36 years received randomized and at weekly intervals single oral doses of placebo, 12.5 mg, 25 mg and 50 mg venlafaxine. EEG recordings, psychometric and psychophysiological tests, and evaluation of pulse, blood pressure and side-effects were carried out at 0, 2, 4, 6, and 8 h. 3. EEG brain mapping demonstrated that venlafaxine exerted a significant action on human brain function as compared with placebo at all three doses, characterized mostly by attenuation of absolute power, increase of relative delta/theta and beta, and decrease of alpha power, as well as by an acceleration of the total centroid fronto-temporally and by its slowing centrally and parietally. These findings are similar to antidepressants such as imipramine. Topographically, drug-induced alterations were most pronounced over both fronto-temporal and the right temporal to temporo-occipital regions. 4. Psychometric and psychophysiological investigations demonstrated significant dose-dependent psychotropic properties of the drug. Multivariate statistics exhibited an improvement of both the noopsyche (e.g. attention, concentration, attention variability, memory, fine motor activity, reaction time performance) and thymopsyche (e.g. drive, wakefulness)) but also significant psychophysiological activation (e.g. in c.f.f., pupillary and skin conductance measures). 5. Time-efficiency calculations showed significant central effects from the 2nd hour onwards, with increasing differences between placebo and treatment up to the 8th hour. Nausea was the most frequent complaint and appeared dose dependent.

Adult↗
PubMed1991

Purification of human cytidine deaminase: molecular and enzymatic characterization and inhibition by synthetic pyrimidine analogs.

Cytidine deaminase has been purified to homogeneity from human placenta by a rapid and efficient procedure consisting of affinity chromatography followed by hydrophobic interaction chromatography. The final enzyme preparation showed a specific activity of 64.1 units/mg, corresponding to about 46,000-fold purification with respect to the crude extract. The enzyme is a 52-kDa oligomeric protein composed of four apparently identical subunits. The acidic isoelectric point is 4.5. The enzyme's stability is strictly dependent on the presence of reducing agents. Amino acid analysis reveals the presence of five thiol groups per monomer which cannot be titrated by Ellman's reagent in the native enzyme. However, the presence of sulfhydryl groups involved in the catalytic activity was evidenced by the inhibition exerted by p-chloromercuribenzoate and heavy metal ions. In addition, the protection effected by the substrate against the p-chloromercuribenzoate inhibition and the competitive inhibition exerted by 5-(chloromercuri)cytidine suggest the presence of a thiol group(s) in the catalytic site of the enzyme. pH studies have shown that the rapid decline of activity occurring at pH 4.5 might result from the protonation of the pyrimidine ring at the N-3 position. The enzyme catalyzes the deamination of cytidine, deoxycytidine, and several analogs, including antineoplastic agents, thus abolishing their pharmacological activity. Therefore, several pyrimidine nucleoside analogs have been tested as potential inhibitors of the enzyme. The competitive inhibition exerted by cytidine analogs having the ribose moiety replaced by aliphatic chains is interesting.

Amino Acids↗
PubMed1991

Presence of NAD pyrophosphorylase in skeletal muscle in dystrophic mice.

NAD pyrophosphorylase (ATP:NMN adenylyltransferase) activity has been measured in the skeletal muscle of dystrophic mice. The amount of this enzyme in the dystrophic mice, as determined by three different methods, was about one half of that in the controls. In addition, the concentration of ATP was too low to be detected in crude extracts of dystrophic mouse skeletal muscle, which were prepared using Tris buffer alone or Tris buffer containing either 3 M KCl, or 1 mM PMSF.

Adenosine Triphosphate↗
PubMed1991

The natural course of cardiac conduction disturbances in myotonic dystrophy.

In this study we noninvasively followed for a mean period of 46 months 21 patients with different grades of myotonic dystrophy to evaluate the course of the involvement of the cardiac conducting system. Six patients (28.6%), 1 affected by a mild and 5 by a severe form of the neuromuscular disorder, showed appearance or deterioration of conduction disturbances suggesting a serious derangement of the specialized tissue; in 3 of them a permanent demand pacemaker was implanted. Conduction defects are the most frequent cardiac manifestations in myotonic dystrophy and become worse with time, mainly in patients with higher degrees of the disease. Furthermore, first-degree atrioventricular block may represent an early sign of developing of more advanced conduction defects.

Adolescent↗
PubMed1991

Psychiatric diagnoses in ulcerative colitis. A controlled study.

Fifty patients with UC and 50 matched controls with urolithiasis were interviewed with the SADS (lifetime version) and completed the SCL-90. According to information given during the SADS, there was a history of psychiatric disturbance in 11 UC patients (22%) and 8 controls (16%). At the time of the interview a psychiatric disturbance was present in 31 UC patients (62%) and four controls (8%), the most frequent diagnoses in the former being minor depression and generalised anxiety disorder. Patients with UC scored significantly higher than the controls on all the different SCL-90 subscales.

Adolescent↗
PubMed1991

The use of antidepressants in the treatment of chronic pain. A review of the current evidence.

In the last 30 years antidepressant drugs have been used increasingly in the treatment of patients with chronic pain. This article reviews the results of some 40 placebo-controlled studies. It is difficult to make comparisons between the various studies because they often differ in terms of pain conditions, patient selection, antidepressant drug used, dosages, trial design, etc. However, in spite of this heterogeneity and other methodological problems it is clear that a wide range of pain conditions are responsive to antidepressant drug treatment, in particular: headache, migraine, facial pain, neurogenic pain, fibrositis, and probably arthritis and rheumatoid arthritis. More data need to be gathered in cancer pain, and in other conditions such as low back pain for which no, or very limited, effect has been shown. The beneficial effects of antidepressant drugs is in most cases of a mild to moderate degree, some time lag is necessary before it is completely manifest, and it tends to persist over time if drug treatment is continued in the long term. Strong evidence of efficacy is not evident for all the antidepressants, and there are probably significant differences in this respect between various drugs. The effect of a drug on pain does not seem necessarily to be related to its effect on mood. Further studies are needed to clarify this topic, and it will be necessary to examine specific pain conditions, compare different antidepressants, with reference to each other and to placebo, further investigate the role of drug plasma concentrations and control for the presence of concomitant psychiatric disturbances and for organic lesions responsible for the pain symptomatology.

Antidepressive Agents↗
PubMed1991

Psychological stress and gastric emptying in normal subjects.

Gastric emptying half-time was measured in 10 healthy volunteers on two different occasions over a one-week interval, with an identical test meal. The first was the control evaluation, and at the second assessment, psychological stress was induced by the technique of dichotomous listening. Psychological and physiological parameters were assessed before and during the test period. No significant or consistent modifications of gastric-emptying time were induced by the stress procedure. Looking at individual subjects instead of mean values, gastric emptying was unchanged in 5 subjects, slower in 3, and faster in the remaining 2. These 3 groups had different mean values on two subscales of the Sixteen Personality Factor Questionnaire.

Adult↗
PubMed1990

Evidence for an inhibitory effect exerted by yeast NMN adenylyltransferase on poly(ADP-ribose) polymerase activity.

We have previously reported for the first time the purification to homogeneity of the enzyme NMN adenylyltransferase (EC 2.7.7.1) from yeast and its major molecular and catalytic properties. The homogeneous enzyme was found to be a glycoprotein containing 2% carbohydrate and 1 mol of adenine residue and 2 mol of phosphate covalently bound per mole of protein. Such a stoichiometry, apparently consistent with that of ADP-ribose, prompted us to further investigate the possibility that NMN adenylyltransferase could be subjected to poly(ADP-ribosylation) in vitro in a reconstituted system. Poly(ADP-ribose) polymerase was purified to homogeneity from bull testis by means of a rapid procedure involving two batchwise steps on DNA-agarose and Reactive Blue 2 cross-linked agarose and a column affinity chromatography step on 3-aminobenzamide-Sepharose; the optimal conditions for the poly(ADP-ribosylation) of exogenous substrates were determined. When pure NMN adenylyltransferase was incubated in the presence of the homogeneous poly(ADP-ribose) polymerase, a marked inhibition of the polymerase was observed, both in the presence and in the absence of histones, while the activity of NMN adenylyltransferase was not affected. The inhibition could not be prevented by increasing the concentrations of either DNA or NAD. Mg2+ did not affect the activity or the inhibition. The significance of such a phenomenon is at present unknown, but it may be of biological relevance in view of the close topological and metabolic relationship between the two enzymes.

Animals↗
PubMed1990

Pain symptoms in an adolescent Italian population.

We have assessed the incidence of four types of self-reported pain symptoms (headache, pain in heart or chest, pain in lower back and muscle soreness) in a randomised sample of 1413 persons from a population of 93481 students aged 14-16 years in the Veneto region of Italy. In males, 26% reported moderate and 1.2% severe pain distress. In female, 35% and 3.7% reported moderate and severe pain respectively. Pain symptoms were positively correlated with anxiety and depressive symptoms and were more frequent in females.

Adolescent↗
PubMed1990

A double-blind comparison of mianserin and maprotiline in depressed medically ill elderly people.

A double-blind, randomized 4-week mianserin vs maprotiline trial was conducted in 48 depressed geriatric medical inpatients. The drug dosages were up to 90 mg of mianserin and up to 150 mg of maprotiline per day. Efficacy was measured by the Geriatric Depression Scale, the Hopkins Symptom Check List depression subscale and the Clinical Global Impression Scale. The overall dropout figure was 27% of the sample. Side effects were relatively similar in the two treatment groups and suggested a safety profile somewhat better than that of the first-generation antidepressants. Mianserin showed some advantages in efficacy over maprotiline, particularly by the 4th week of the trial, but the overall figures of treatment responders were rather small (Geriatric Depression Scale: mianserin 48%, maprotiline 30%). Clinical trials vs placebo are needed to clarify the role of antidepressant pharmacotherapy in depressed geriatric medical inpatients.

Aged↗
PubMed1990

Pain and personality in duodenal ulcer: a preliminary report.

Personality factors measured by the Cattell's 16 Personality Factor Questionnaire were assessed for 78 duodenal ulcer patients with moderate to severe pain and in 30 duodenal ulcer patients with mild or no pain. The two groups were comparable for relevant sociodemographic variables. Patients with moderate to severe pain were significantly more tender-minded, kindly, and tended to be more introspective and glum than those reporting mild or no pain. However, the reported differences are small; adjustment of the p values to avoid Type I errors makes these differences no longer statistically significant. These results must be considered preliminary; further studies are necessary to understand the topic better.

Abdominal Pain↗