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Biomedical subjects

M Marra

Publications and source records attributed to M Marra.

At least 109 records · Page 6Linked to original sources
PubMed1994

The 30-kilodalton protein present in purified fusicoccin receptor preparations is a 14-3-3-like protein.

We have recently reported on the purification of the fusicoccin (FC) receptor from corn (Zea mays L.) and its identification by photoaffinity labeling (P. Aducci, A. Ballio, V. Fogliano, M.R. Fullone, M. Marra, N. Proietti [1993] Eur J Biochem 214: 339-345). Pure preparations of FC receptors, obtained under nondenaturing conditions, showed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis two doublets of proteins with apparent molecular masses of 30 and 90 kD. In the present paper we describe the isolation and identification of the primary structure of the 30-kD doublet proteins. Sequencing studies of peptides resulting from the digestion of the 30-kD protein showed a full identity with a 14-3-3-like protein from corn, named GF14. The 14-3-3 family is a class of proteins that is widely distributed in eukaryotes and is known to play various regulatory roles. The 30-kD protein has been immunologically identified by specific antibodies prepared against a synthetic peptide based on the determined amino acid sequence. A similar protein is recognized in partially purified FC receptor preparations from bean and spinach leaves.

14-3-3 Proteins↗
PubMed1994

[Idiopathic unilateral hypoplasia of the breast].

Unilateral hypoplastic breast is a rare anomaly. The correction of the asymmetry is usually achieved by the use of breast implants or breast expanders. Sometimes the controlateral breast must be modified to gain a good symmetry.

Adult↗
PubMed1993

Purification and photoaffinity labeling of fusicoccin receptors from maize.

Crude soluble proteins from plasma membranes of maize shoots were purified (following the increase of fusicoccin-binding specificity) by using an original multi-step HPLC procedure. The method, based on a combination of adsorption, ion-exchange and gel-filtration chromatographies, is quick, efficient and does not damage the binding activity. It allows a 5000-fold increase of specific activity; SDS/PAGE of purified fractions shows two doublets that correspond to proteins with apparent molecular masses of 90 kDa and 30 kDa. Crude or partially purified material was irradiated for various periods in the presence of a tritiated azido analogue of fusicoccin. The electrophoretic analysis of the irradiated material shows that with a short irradiation time only the 90-kDa band is radiolabeled, whereas, as the irradiation time increases, a 30-kDa band becomes radiolabeled and less radioactivity is detected in the 90-kDa band. Irradiation of the crude material in the absence of the analogue results in a decrease of the binding capability of fusicoccin. The irradiated preparation also shows a decrease of photolabeling of the 90-kDa band. Our data suggest that the 90-kDa protein is the functional fusicoccin receptor. This conclusion is at variance with results of other authors who suggest the 30-kDa protein as the true receptor.

Binding Sites↗
PubMed1993

Phospholipase A2 affects the activity of fusicoccin receptors.

Biochemical properties of fusicoccin receptors are strongly influenced by the phospholipid environment. In this report we have studied the effect of different exogenous phospholipases on fusicoccin binding ability of both plasma membrane and solubilised receptors. Among the phospholipases tested only phospholipase A2 showed an inhibitory effect on fusicoccin binding. In particular, the influence of this enzyme on the time course and reversibility of the fusicoccin binding reaction was studied. The inhibitory effect of phospholipase A2 was the consequence of fatty acid release. The usual fatty acids of plasma membrane phospholipids were active in inhibiting the interaction of fusicoccin with its receptors. It is concluded that a phospholipid associated to the fusicoccin receptor might play a significant role in the modulation of binding.

Binding Sites↗
PubMed1993

[Dietetic therapy of obesity. Preliminary considerations on the combined therapy with ursodeoxycholic acid in the prevention of cholesterol lithiasis].

The use of ursodeoxycholic acid (UDCA) was found useful in reducing the incidence of cholelithiasis (p < 0.05) without provoking any other alteration in hepatic function. This preliminary experience underlines the appropriateness of carrying out further studies on the utility of preventive treatment for the formation of cholesterol calculi with biliary acids, and in particular UDCA, in obese subjects who are receiving dietary treatment. The protective action of ursodeoxycholic acid in the prevention of biliary lithiasis during the course of low-calorie diets was evaluated in 40 obese subjects (31 females, 9 males) treated for 4 months with fibre-rich (approximately 40 g/day) low-calorie diets of 900-1200 Kcal, of whom 20 received 450-750 mg of UDCA/day and 20 were treated with placebo.

Adult↗
PubMed1992

Differences in pulmonary biochemical and inflammatory responses of rats and guinea pigs resulting from daytime or nighttime, single and repeated exposure to ozone.

Rats and guinea pigs were exposed to 0.8 mg ozone (O3)/m3 (approximately 0.4 ppm) for 12 hr during the daytime, 12 hr during the nighttime, or continuously to investigate circadian variation in O3-induced pulmonary toxicity during single and repeated O3 exposures. Biomarkers in bronchoalveolar lavage (BAL) fluid and lung tissues were measured as indicators of biochemical and inflammatory responses. Nighttime O3 exposure of rats resulted in larger increases of protein, albumin, and inflammatory cells in BAL fluid compared to those after daytime O3 exposure and this daytime-nighttime difference was statistically significant (p < 0.05). Single daytime or nighttime O3 exposure of guinea pigs resulted in comparable increases of BAL fluid proteins and inflammatory cells without a daytime-nighttime difference. Nighttime and continuous O3 exposure of rats for 3 days resulted in comparable increases in lung antioxidant enzyme activities, both of which differed statistically from effects from daytime O3 exposures (p < 0.05). Continuous O3 exposure of guinea pigs for 3 days caused, in general, statistically larger increases in lung tissue parameters compared to nighttime O3 exposures (p < 0.05). These results suggest that the extent of O3-induced acute pulmonary biochemical and inflammatory responses is directly related to the level of physical and respiratory activity. For rats, effects from continuous O3 exposure appear to be controlled by the nighttime, physically active period. In guinea pigs, the comparable responses following daytime or nighttime O3 exposure seem in accordance with their random behavioral daily activity pattern. This study supports the view that physical activity-related increases in inhaled dose significantly enhance the pulmonary O3 responses.

Administration, Inhalation↗
PubMed1992

Some Properties of a Functional Reconstituted Plasmalemma H-ATPase Activated by Fusicoccin.

Fusicoccin was shown to stimulate the ATP-driven, intravesicular acidification of liposomes reconstituted with crude fusicoccin receptors and the H(+)-translocating ATPase, both solubilized from maize (Zea mays L.) plasma membrane. The present paper reports optimal conditions for dual reconstitution and fusicoccin activation as well as the biochemical characterization of the effect of fusicoccin on this system. Fusicoccin stimulation of proton pumping was dependent on pH and fusicoccin concentration. Its specificity was demonstrated by the positive effect of two cotylenins that have a high affinity for fusicoccin receptors and by the negative response to 7,9-epideacetylfusicoccin, an inactive fusicoccin derivative. Kinetic measurements at different ATP concentrations showed that fusicoccin increases the V(max) of the enzyme. Fusicoccin stimulation of maize H(+)-ATPase was also maintained when receptors from maize were substituted by those from spinach (Spinacia oleracea L.).

Journal Article↗
PubMed1992

Rat model to investigate the treatment of acute nitrogen dioxide intoxication.

1. The pulmonary toxic events induced by acute nitrogen dioxide (NO)2 exposure were studied in the rat to develop an inhalation model to investigate therapeutic measures. 2. A good correlation was observed between the lung weights and severity of the atypical pneumonitis. The pulmonary effects observed, became more pronounced with increasing NO2 concentrations (0, 25, 75, 125, 175 or 200 ppm, 1 ppm NO2 = 1.88 mg m-3 NO2) and exposure times (5, 10, 20 or 30 min). 3. An adequate NO2 concentration is 175 ppm, because it can induce a severe lung injury without mortality. This makes it possible to investigate suitable therapeutic interventions for several days. 4. Following acute inhalatory NO2 intoxication, transformation of NO2 to nitrate is presumably more notable than transformation to nitrite. 5. The transformation of NO2 to nitrate in lung tissue causes a slight increase in the serum nitrite concentration, which does not induce measurable formation of methaemoglobin. 6. Presumably, methaemoglobin does not contribute to the toxicity of NO2 intoxication.

Administration, Inhalation↗
PubMed1992

Cognitive effects of antiepileptic drug discontinuation.

We studied the cognitive effects of antiepileptic drugs (AEDs), by investigating epileptic patients who were seizure-free for a long time and who were undergoing fixed monotherapy. Ninety patients [27 with phenobarbital (PB), 18 with carbamazepine (CBZ), 16 with phenytoin (PHT), and 29 with valproate (VPA)] were examined by a neuropsychological battery exploring intelligence, vigilance, attention, memory, and visuomotor performances at full AED dose (T1) and compared to 28 normal volunteers. We also evaluated the effects of AED discontinuation by retesting patients 3 months after reduction at half drug dose (T2) and 3 months (T3) and 1 year (T4) after complete discontinuation. Our findings showed that patients receiving CBZ did not differ from controls at any time of examination. Patients receiving PB had significant differences only at T1 (visuomotor performance and immediate spatial memory). Patients receiving VPA showed differences in attention, visuomotor performance, verbal span and sensory discrimination tasks at T1, in visuomotor performance at T2 and in spatial span at T3, whereas no differences were detected at T4. Patients receiving PHT had a difference in intelligence and visuomotor performance at T1, in intelligence at T2, and no differences at T3 or T4. This study model is useful for investigating the cognitive effects of AED because it allows selection of a uniform sample, eliminating variables such as type, frequency, and gravity of seizures that complicate this kind of study.

Adolescent↗
PubMed1991

Structural and biochemical effects in lungs of Japanese quail following a 1-week exposure to ozone.

The effect of ozone inhalation on birds was investigated. Japanese quail were exposed continuously to 0, 0.3, 1.0, and 3.0 mg/m3 ozone (0, 0.15, 0.50, and 1.50 ppm, respectively) for 7 days. Pulmonary effects were determined by light and electron microscopy as well as by biochemistry. Focal areas of hemorrhages were noticed in the birds exposed to 1.0 mg/m3 ozone. Additional effects after exposure to 1 mg/m3 included loss of cilia in trachea and bronchi, an inflammatory response, and necrosis of air capillary epithelial cells. Following exposure to 3 mg/m3 many atria of tertiary bronchi were completely obstructed by extensive hemorrhages, metaplasia of atrial wall cells, and hypertrophy of smooth muscle cells. Lung biochemistry data revealed that in the 3 mg/m3 group lactate dehydrogenase, glucose-6-phosphate dehydrogenase, and glutathione reductase activities were significantly increased. In the 0.3 and 1.0 mg/m3 exposure groups no effects on lung antioxidant enzymes were observed. In conclusion, Japanese quail appear to respond to ozone exposure in a different way than mammals. Since no signs of repair in air capillary epithelium after 7 days of continuous exposure were observed, the quail seems to lack the morphological and biochemical repair ability as is observed in mammals. Therefore, more research of the effects of ozone on birds seems to be necessary, both from a mechanistic and an ecological point of view.

Administration, Inhalation↗
PubMed1991

The reservoir-pusher in breast reconstructive surgery.

This paper describes a surgical instrument designed for the subcutaneous insertion of the Becker expander reservoir. The instrument has proven to be particularly easy to use, and it has several safety features for avoiding rupture of the reservoir and the linkup tube.

Breast↗
PubMed1990

IP3 levels and their modulation FY fusicoccin measured by a novel [3H] IP3 binding assay.

A recently developed sensitive assay based on the binding reaction of IP3 to bovine adrenal preparations has been utilized for determining the level of endogenous inositol-1,4,5 trisphosphate (IP3) in maize roots and coleoptiles. The amount of IP3 found in these tissues ranges from 0.1 to 1.0 nmol g-1 fresh weight. Reproducible results were obtained with extracts of tissues from a same harvest, while they showed a 2-3 fold variation when different batches of plantlets were compared. The fungal phytotoxin fusicoccin (FC) known to affect several physiological processes in higher plants, increases the level of IP3 in coleoptiles. This observation suggests that IP3 might be involved in the transduction of the FC encoded signal from its receptors at the plasmalemma level to the cell machinery.

Glycosides↗
PubMed1990

Fusicoccin: receptors and endogenous ligands.

The first event in the mode of action of the fungal phytotoxin fusicoccin is the binding to specific receptors located at the plasma membrane. They are very likely related to the presence of endogenous compounds able to compete with FC for binding to its receptors. Some biochemical properties of these proteins conform to criteria commonly used for receptors. A functional relationship between fusicoccin receptors and the plasma membrane H(+)-ATPase which is assumed to be the final physiological target of fusicoccin, has been recently suggested. New support in favour of this relationship has been sought by studying a model system prepared by insertion into liposomes of preparations from maize tissues of the two proteins. The model system is capable of H(+)-translocation on ATP addition and the translocation is markedly stimulated by fusicoccin. Thus, it represents a promising tool for the understanding of fusicoccin signal transduction at the molecular level, since it can assist in the detection and assay of the transduction chain components contained in the impure protein preparations.

Binding Sites↗