PubMed Health⌕ Search

Biomedical subjects

G Baldini

Publications and source records attributed to G Baldini.

At least 19 recordsLinked to original sources
PubMed1992

Cloning of a Rab3 isotype predominantly expressed in adipocytes.

We have isolated the cDNA for Rab3D, an additional member of the small molecular weight GTP-binding protein family. Rab3D message is abundant in mouse adipocytes. It is increased during differentiation of 3T3-L1 cells into adipocytes, temporally coincident with the appearance of the insulin-sensitive glucose transporter GLUT4. Rab3D is a close homolog of Rab3A, which is found on the cytoplasmic surface of neurosecretory vesicles and which may be involved in their regulated secretion. Since our previous work showed that in permeabilized adipocytes nonhydrolizable GTP analogs mimic insulin in triggering exocytosis of GLUT4-containing vesicles, Rab3D may be involved in the insulin-induced exocytosis of GLUT4-containing vesicles in adipocytes.

3T3 Cells↗
PubMed1992

DNA torsional dynamics by multifrequency phase fluorometry.

The time decay of the fluorescence polarization anisotropy of calf thymus DNA-ethidium complexes is obtained from measurements with sine-modulated excitation employing the so-called multifrequency phase fluorometry. A torsional dynamics model developed by J. M. Schurr [(1984) Chemical Physics, Vol. 84, pp. 71-96] and translated into the frequency domain is found here to describe accurately DNA-ethidium fluorescence data collected under modulated excitation. At a low dye/DNA ratio (1:400) the value of the DNA torsional constant (alpha = 4.63 +/- 0.2 10(-12) dyne cm) fitting the data agrees very well with the known values of alpha. When the measurements are extended to a higher ethidium/DNA ratio, energy transfer effects between intercalated dyes are observed. A theoretical prediction of the donor and acceptor dye contributions to the fluorescence polarization anisotropy is made here, taking into account also dye-dye distance distributions.

Animals↗
PubMed1992

[Chronic alcoholism and arterial hypertension. Contribution to the comprehension of the phenomenon and practical implications].

Alcohol abuse is a frequent contributor to elevated blood pressure. 710 chronic alcoholics, aged 26-60 years, admitted for detoxification were studied. We compared hypertension prevalence in alcoholics with that in a similar group of non-alcoholics matched for age, sex, and miscellaneous diseases. The prevalence of hypertension was higher in heavy drinkers (11.4%) than in non drinker subjects (3.4%). Abstinence from alcohol during hospitalization was followed by normalization of hypertensive status in a high percentage of patients (70%). The majority of hypertensive alcoholics (75%) developed target organ damage ranging from retinopathy to hypertensive cardiomyopathy and renal lesion. In a 4.6 +/- 2.8 years follow-up study of 42 hypertensive alcoholic subjects, we observed that hypertension was 26% in those who abstained alcohol ingestion versus 84% in those who remained actively alcoholics. Four patients died of liver failure and two of stroke.

Adult↗
PubMed1992

[Lactate dehydrogenase and its isoenzymes in respiratory diseases in children].

Total Lactate Dehydrogenase (LD, EC 1.1.1.27) activity in serum and LD isoenzymes were quantified in 161 children (51 with pneumonia at the time of diagnosis, 60 hospitalized for asthma in acute period and 50 healthy subjects) to ascertain the relationship of these markers with injury of lung tissue. No statistical variations, between different groups in total activity, were found. Significantly decreased proportions of LD1 (p less than 0.000001) and of LD2 (p less than 0.000001) with simultaneous increase of LD4 (p less than 0.000001) and LD5 (p less than 0.000001) resulted in children with pneumonia, as to asthmatic or healthy subjects. Investigators conclude that LD should be determined in every patient with pneumonia because of the presence of a specific LD isoenzyme pattern.

Asthma↗
PubMed1991

Insulin and nonhydrolyzable GTP analogs induce translocation of GLUT 4 to the plasma membrane in alpha-toxin-permeabilized rat adipose cells.

Rat adipose cells treated with Staphylococcus aureus alpha-toxin are permeable and retain their ability to respond to insulin after hormone treatment. The GLUT 4 glucose transporter isoform, specific to fat and muscle cells, is translocated normally from low density microsomes to the plasma membrane in permeabilized cells. Addition of guanosine 5'-O-(3-thiotriphosphate), guanylyl imidodiphosphate, or guanylyl beta, gamma-methylenediphosphate to permeabilized adipocytes induces an insulin-like translocation of GLUT 4 to the plasma membrane; GTP or adenosine 5'-(beta, gamma-imino)triphosphate has no effect. No translocation of GLUT 4 is observed when GTP analogs are added to intact adipocytes. These results suggest the involvement of a GTP-binding protein in insulin-triggered recruitment of GLUT 4 to the cell surface.

Adipose Tissue↗
PubMed1990

Conformation of intercalated DNA plasmids investigated by circular dichroism and dynamic light scattering.

Two DNA plasmids, pEGF and pACL29, intercalated with ethidium bromide (EB), have been examined by circular dichroism (CD) and dynamic light scattering (DLS). CD and DLS data show significant changes when the EB/DNA (phosphates) ratio reaches a value of r approximately equal to 0.13. The translational and rotational diffusion coefficients, predicted assuming that plasmids can be described by a string of beads, and the CD spectrum, suggest that a transition from an interwound to a toroidal conformation is likely to occur.

Circular Dichroism↗
PubMed1989

Bilitranslocase is the protein responsible for the electrogenic movement of sulfobromophthalein in plasma membrane vesicles from rat liver: immunochemical evidence using mono- and poly-clonal antibodies.

Monoclonal antibodies raised against bilitranslocase, may display either inhibitory or enhancing activity on the electrogenic transport of sulfobromophthalein, evoked in rat liver plasma-membrane vesicles by the addition of valinomycin in the presence of K+. In both cases, the target protein is identified with a 37 kDa band in SDS-mercaptoethanol gel electrophoresis of solubilized membranes. The electrophoretically homogeneous protein isolated by ion-exchange chromatography, corresponds in all respects to the 37 kDa protein band of bilitranslocase, obtained in the past by different techniques. Using this protein as antigen, a polyclonal monospecific antibody preparation has been obtained. As expected, the antibody preparation inhibits the electrogenic movement of sulfobromophthalein in plasma membrane vesicles from rat liver. It is concluded that the 37 kDa protein of bilitranslocase is at least a necessary component of the transport system involved in the sulfobromophthalein movement in plasma membrane.

Animals↗
PubMed1989

[A controlled study on the action of a new formulation of ambroxol in asthmatiform bronchitis in children].

A comparison between the action of Ambroxol and Acetylcysteine was carried out in 28 children aged 2 to 13 (mean 7 years 3 months) affected with spastic bronchitis. 14 patients were treated daily for 10 days by the oral route with 30 mg of Ambroxol (2 sachets) and 14 with 200-300 mg of Acetylcysteine (2-3 sachets). Quantity and quality of sputum, difficulty in expectorating, cough, dyspnea, bronchial bruits, were assessed before the treatment, 5 days into it and at the end. Both drugs were effective and well tolerated, but Ambroxol proved to be more rapid in achieving a satisfactory improvement than Acetylcysteine.

Acetylcysteine↗
PubMed1988

Mischarging Escherichia coli tRNAPhe with L-4'-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenylalanine, a photoactivatable analogue of phenylalanine.

The Boc-protected derivative of a photoactivatable, carbene-generating analogue of phenylalanine, L-4'-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenylalanine [(Tmd)Phe], was used to acylate 5'-O-phosphorylcytidylyl(3'-5')adenosine (pCpA). A diacyl species was isolated which upon successive treatments with trifluoroacetic acid and 0.01 M HCl yielded a 1:1 mixture of 2'(3')-O-(Tmd)phenylalanyl-pCpA and of its 2'-5'-phosphodiester isomeric form. Adapting a procedure introduced by Hecht's group [Heckler, T.G., Chang, L.H., Zama, Y., Naka, T., Chorghade, M.S., & Hecht, S.M. (1984) Biochemistry 23, 1468-1473], brief incubation of a 15 molar excess of this material with Escherichia coli tRNAPhe, missing at the acceptor stem the last two nucleotides (pCpA), in the presence of T4 RNA ligase and ATP afforded "chemically misaminoacylated" tRNAPhe in approximately 50% yield. Following chromatographic purification on DEAE-Sephadex A-25, benzoylated DEAE-cellulose, and Bio-Gel P-6, the misaminoacylated tRNAPhe was characterized by (i) urea-polyacrylamide gel electrophoresis, (ii) enzymatic reaminoacylation under homologous conditions following chemical deacylation, and (iii) its ability to stimulate protein synthesis in an in vitro translation system which, through the addition of the phenylalanyl-tRNA synthetase inhibitor phenylalaninyl-AMP, was unable to charge its endogenous tRNAPhe. The data demonstrate that we have prepared a biologically active misaminoacylated tRNAPhe.

Azirines↗
PubMed1987

Nonspecific interactions in dye binding to DNA. Influence of alcohols and amides.

The binding of a few drugs (ethidium bromide, propidium diiodide, proflavine and actinomycin D) to DNA has been investigated in aqueous solutions to which cosolvents of different polarity have been added. It is found that both alcohols (less polar than water) and amides (more polar) lower the binding constant according to a linear relationship between the intercalation free energy and cosolvent concentration. The main action of cosolvents cannot be described in terms of electrostatic effects, since they predict much smaller changes in the binding constant than those observed. It appears instead that relevant solvation effects are responsible for the binding strength of the different dyes to DNA. As a general result, it is found that solvation effects largely contribute to the intercalation free energy, thereby weakening the influence of nonspecific interactions at the intercalation site.

Alcohols↗
PubMed1986

Cellular localization of sulfobromophthalein transport activity in rat liver.

The movement of sulfobromophthalein is measured in rat liver plasma-membrane vesicles by direct dual-wavelength spectrophotometry. The technique is based on the principle that the dye, when entering a more acidic compartment, changes its absorption in the visible region. From this study it may be concluded that, among the different cellular subfractions, only liver plasma-membrane vesicles can catalyze electrogenic transport of sulfobromophthalein. Plasma membranes from erythrocytes are unable to perform such a function. The movement follows the distribution pattern of (Na+ + K+)-ATPase and it is therefore concluded that this process occurs exclusively at the sinusoidal membrane level. Inhibition studies confirm that the process is catalyzed by bilitranslocase.

Animals↗
PubMed1985

Measurement of the association of cholephylic organic anions with different binding proteins.

The binding of the colored cholephylic anions tetrabromosulfonphthalein (BSP), di-bromosulfonphthalein (DBSP), indocyanine green (ICG) and thymol blue (ThB) to a number of protein preparations including bovine serum albumin, human serum, rat hepatic cytosol and purified rat liver bilitranslocase has been studied by a direct spectrophotometric method. The experimentation provides extinction coefficients, dissociation constants and number of binding sites for the different complexes between dyes and the various proteins. Data obtained by this technique were in excellent agreement with those obtained on the same samples by ultrafiltration. The data presented indicate that the direct spectrophotometry applied to these dyes is simple, rapid and reproducible, making this the approach of choice during the purification of binding proteins when the binding capacity is the only useful criterion to follow the progress of the procedure.

Animals↗
PubMed1985

Sex differences of nicotinate-induced hyperbilirubinemia in Gilbert's syndrome. Implication of bilitranslocase function.

Intravenous administration of nicotinic acid (NA) is followed by an increase in serum unconjugated bilirubin level. This effect is higher in Gilbert's syndrome (GS) and this test has been used in the diagnosis of the syndrome. After administration of 5.9 mumol NA/kg body weight, the maximal increment of serum unconjugated bilirubin and the area under the bilirubin concentration time curve (AUC) were significantly higher (P less than 0.01) in GS males than in GS females. The half-life of the first fast slope of plasma disappearance curve of the drug was also significantly prolonged in GS males as compared to GS females (15.91 +/- 1.12 vs 9.13 +/- 1.25 min, mean +/- SEM, P less than 0.005). The maximal bilirubin increment and AUC were linearly correlated (P less than 0.01) with NA plasma half-life. Purified preparations of bilitranslocase, a liver plasma-membrane protein involved in bilirubin and sulfobromophthalein (BSP) transport, specifically bound NA and the drug competitively inhibited BSP uptake in rat liver plasma membrane vesicles (Ki = 50 nM). These data suggest that, in addition to the hemolytic effect of the drug, NA-induced hyperbilirubinaemia could be also due to a competition between the two anions at the sinusoidal plasma membrane level. A possible implication of bilitranslocase in GS is considered.

Adolescent↗
PubMed1985

The implication of bilitranslocase function in the impaired rifamycin SV metabolism in Gilbert's syndrome.

1. The plasma disappearance rate and the increment in plasma unconjugated bilirubin after intravenous administration of 5.9 mumol of rifamycin SV (RSV)/kg body wt. were investigated in 51 subjects with Gilbert's syndrome and 35 control subjects of both sexes. 2. Both the plasma disappearance rate and the unconjugated hyperbilirubinaemia after RSV administration were higher (P < 0.001) in Gilbert's syndrome. Females, both normal and with the syndrome, showed a significantly shorter t1/2 and a lower hyperbilirubinaemic response as compared with males. A linear correlation (P < 0.001) was present between RSV plasma half-life and the hyperbilirubinaemic response. 3. In vitro, RSV was shown to inhibit sulphobromophthalein (BSP) uptake in rat liver plasma-membrane vesicles with a Ki of 20 mumol/l. Evidence that this effect was due to competition for bilitranslocase was sought on preparations of the purified protein. Under these experimental conditions, RSV inhibited BSP binding with a Ki of 17 mumol/l. 4. Since RSV competes with BSP for binding to bilitranslocase in vitro, the data are interpreted as suggesting that reduced bilitranslocase function might underlie the delayed RSV plasma clearance and the exacerbated unconjugated hyperbilirubinaemia present in Gilbert's syndrome.

Adolescent↗