Hormones and signal transduction in protozoa.
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Animals↗
Biomedical subjects
R Chiesa
Publications and source records attributed to R Chiesa.
A mutant of basic fibroblast growth factor that has lost the ability to stimulate plasminogen activator synthesis in endothelial cells.
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3T3 Cells↗
[Coarctation and hypoplasia of the abdominal aorta].
In this study we report one case of abdominal aortic coarctation of unknown etiology, probably congenital or connatal, and two cases of aortoiliac occlusion in young non-diabetic patients, with an intrinsically small aortoiliac tree. These syndromes usually appear in young age; the principal clinical features are arterial insufficiency involving the lower extremities, often well tolerated, and hypertension. The differential diagnosis is with primitive atherosclerotic or inflammatory pathology. Echography and Doppler-echography can be helpful in the diagnosis, but intra arterial digital angiography is mandatory in confirming it. Medical therapy is usually unsuccessful, especially in controlling blood pressure, therefore surgery still remains the treatment of choice, together with PTA that can be applicable in selected cases.
Adult↗
[Cigarette smoking among high school students in Brescia: analysis of relations between smoking habit and knowledge, attitudes socioeconomic and behavioral factors].
A sample of high school students in grade 9 and 13 (14-15 and 18-19 years old respectively) in Brescia, North Italy, were interviewed to assess the relationship of smoking habit with attitudes, knowledge, behavioural and socio-environmental factors among adolescents. The associations between smoking habit, considered as a dichotomous response variable, and the other variables were assessed by estimating the prevalence ratios. The following variables were found to be associated with the students' smoking: best friend and/or partner smoking, sibling smoking, alcohol drinking and the students' judgement of the health risks of smoking. Although no conclusion can be drawn on the causal relationship of these associations due to the cross-sectional design of the survey, these findings suggest that social environment influences adolescents' smoking more than family life does. Furthermore, the knowledge of the health risks of smoking was not associated to adolescents' smoking.
Adolescent↗
Liver genotoxic activity of an epoxide derivative of the hepatocarcinogenic beta-blocker DL-ZAMI 1305.
A single administration of the sex-dependent hepatocarcinogenic beta-blocker DL-1-(2-nitro-3-methyl-phenoxy)-3-tert-butylamino-propan-2-ol (DL-ZAMI 1305) induces dose-dependent liver DNA damage, as evaluated by alkaline sucrose gradient analysis, in female but not in male Fisher 344 rats. A single administration of the direct mutagenic epoxide-derivative of DL-ZAMI 1305 3-methyl-2-nitro-1-(2,3-epoxypropoxy)-benzene induces dose-dependent DNA damage in the liver of animals of both sexes. However, also in this case, the genotoxic activity of the compound appears to be significantly higher in female than in male rats. A DNA-damaging capacity similar in the two sexes is instead exerted by DL-ZAMI 1305-unrelated direct mutagens, like N-methyl-N-nitrosourea (MNU) and methyl-methanesulfonate (MMS). The data confirm the sex-dependent susceptibility of rat liver to the genotoxic activity of DL-ZAMI 1305-related molecules, also in the absence of an absolute requirement for a metabolic activation of the compound.
Animals↗
[Treatment of obliterating arteriopathies of the lower limbs using angioplasty. Comparison of 2 techniques of recanalization: Nd-YAG laser and radiofrequency thermal probe].
The Authors report their experience about 20 cases of femoro-popliteal revascularization: in 15 cases a Nd-YAG Laser was used; in 5 cases a unity which employs radiofrequency energy to heat the tip (Thermoprobe) was utilized. We obtained an immediate recanalization in 19 out of 20 superficial femoral arteries with two early thrombosis. In 12 patients of the first group a significant increase of the ankle-brachial index (45%) was seen; it remained unchanged during the follow-up. We had successful revascularization in all the 5 patients of the second group (Thermoplaster). In selected cases, when the lesion is shorter than 10 cm, not completely calcified, and there is a valid run-off, Laser angioplasty could be a valid alternative to surgery or medical therapy.
Aged↗
The apparent molecular size of native alpha-crystallin B in non-lenticular tissues.
The apparent molecular size of the native alpha-crystallin B in cytosol preparations from rat heart, brain and retina was determined by gel permeation chromatography, detecting the protein by immunochemical assay (ELISA), using an alpha-crystallin specific antiserum. Native alpha-crystallin from cytosol preparations of rat lens cortex was used as a reference. alpha-Crystallin B present in all three cytosol preparations from non-lenticular tissues eluted in a single symmetrical peak, with the same elution volume as alpha-crystallin from lens cortex cytosol preparations, corresponding to an apparent average molecular size of 0.8 x 10(6) Da. No other species could be detected. The results indicate that the alpha-crystallin aggregates characterized by an apparent average molecular mass of 0.8 x 10(6) Da, and considered to be the native, physiological form of the protein in the lens, are indeed not specific to lens tissue. Furthermore, the size of these alpha-crystallin aggregates is independent of their polypeptide composition. Aggregates found in the lens, composed of alpha A and alpha B polypeptides and their respective phosphorylated forms alpha Ap and alpha Bp, are similar in size to those found in heart, brain and retina, containing the alpha B but not the alpha A polypeptide.
Animals↗
Chemical structure and genotoxic activity of the hepatocarcinogenic beta-blocker DL-ZAMI 1305.
A single administration of the sex-dependent hepatocarcinogenic beta-blocker DL-1-(2-nitro-3-methyl-phenoxy)3-tert-butylamino-propan-2-ol (DL-ZAMI 1305) induces liver DNA damage, as evaluated by alkaline sucrose gradient analysis, in female but not in male Fisher 344 rats. The shift of the methyl-group from the 3-position of the aromatic ring of DL-ZAMI 1305 to the 4- and 5-position causes the progressive decrease of the genotoxic activity of the molecule. No effect on the DNA-damaging capacity of DL-ZAMI 1305 is instead observed when the NO2 group of the aromatic ring is reduced to an NH2 group. Bis-demethylation of the side chain of DL-ZAMI 1305, or its modification to an alpha-hydroxicarboxylic acid or glycol, increases the DNA-damaging capacity of the molecule, which becomes genotoxic also for the liver of the male rat. Thus, modifications of the chemical structure of the aromatic ring or of the side chain of DL-ZAMI 1305 affect the genotoxic activity of the molecule both in male and female rat liver. The modifications of the side chain of DL-ZAMI 1305 investigated in the present work are likely to occur in vivo as a consequence of the hepatic metabolism of the molecule. Sex-dependent differences in the activity of the liver drug-metabolizing system might explain the different genotoxic and oncogenic activity of DL-ZAMI 1305 in the two sexes.
Adrenergic beta-Antagonists↗
The dephosphorylation of lens alpha-crystallin A chain.
The present communication reports the presence of a phosphoprotein phosphatase activity in bovine lens preparations which dephosphorylates alpha Ap, the phosphorylated form of alpha A, one of the alpha-crystallin polypeptides, in a Ca2+/calmodulin dependent manner. The activity was found in soluble preparations from epithelial cells but it could not be detected in similar preparations from fiber cells. A 60,000 Mr calmodulin binding polypeptide and a 15,000 Mr polypeptide found in the epithelial cell preparations comigrated in SDS-PAGE with the A and B subunits of bovine brain calcineurin (phosphoprotein phosphatase 2B) respectively. The 15,000 Mr was specifically recognized by an anti-bovine brain calcineurin antiserum. Bovine brain calcineurin was as effective in dephosphorylating alpha Ap as the lens preparations. Thus, it is likely that the activity present in the lens is related to this enzyme. The results indicate that the lens specific polypeptide alpha A may be subject to metabolic control through phosphorylation and dephosphorylation pathways regulated by cAMP and calcium respectively. Changes in the activities of these pathways appear to occur during differentiation of the lens epithelial cell and may be related to gene regulation during the differentiation process.
Animals↗
[Pancreas and kidney transplant in diabetico-uremic patients].
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Adult↗
Differential synthesis and phosphorylation of the alpha-crystallin A and B chains during bovine lens fiber cell differentiation.
[14C]-amino acids and [32P]-orthophosphate incorporation experiments were carried out in bovine lenses in culture to study the synthesis and phosphorylation of alpha-crystallin A and B polypeptides during differentiation of the lens fiber cells. Following culture, the [14C] or [32P]-labelled alpha-crystallin was isolated by gel filtration chromatography from four regions of the lens corresponding to: A) quiescent epithelial cells, B) dividing epithelial cells and early stages of elongation, C) young elongating fibers, and D) mature fibers from the superficial cortex. The incorporation of label into the alpha-crystallin primary gene products alpha A2 and alpha B2 and their respective phosphorylated forms alpha A1 and alpha B1 was determined by isoelectric focusing and radioautography. Different synthesis and phosphorylation patterns were observed in alpha A and alpha B polypeptides. Synthesis and phosphorylation of the alpha B chain occurs most actively in the epithelial cells, both processes decrease during differentiation and there is no net accumulation of the phosphorylated form alpha B1 in the mature fiber cell. In contrast to the B chain, the A chain synthesis, minimal in the epithelial cell, increases with differentiation. Most striking, the A chain phosphorylation, not detectable in the epithelial cells, increases with differentiation. In the mature fiber cell, the phosphorylated form alpha A1 accounts for one third of the A chain. These observations indicate that the two chains may have different functions. the synthesis and phosphorylation patterns of alpha A suggest a lens-specific function of this polypeptide in the fiber cell and in the terminal differentiation process.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acids↗
Purification of a 43,000 dalton aggregate generated from alpha-crystallin.
A procedure is presented for the purification of an aggregate of covalently linked polypeptides of alpha-crystallin. Using either iron catalyzed oxidation or UV irradiation, 6-12% of calf lens alpha-crystallin can be converted to a 43,000 Da aggregate containing non-reducible cross-linked polypeptides as indicated by SDS-PAGE under reducing conditions. The 43,000 Da aggregate generated by Fe2+ oxidation can be isolated to approximately 85% homogeneity with respect to its relative molecular weight on SDS-PAGE. The procedure can be performed in two steps; 1) gel filtration of the oxidized alpha-crystallin under deaggregating and reducing conditions, and 2) preparative SDS-PAGE of the 43,000 Da aggregate-enriched peak obtained by filtration. The 43,000 Da aggregate band can be recovered from the polyacrylamide gels using a new preparative electroelution technique. 1.0 +/- 0.3 mg of purified 43,000 Da aggregate can be obtained from 100 mg of Fe2+ oxidized alpha-crystallin. The described methodology will facilitate further characterization of this 43,000 Da alpha-crystallin aggregate.
Animals↗
Fe2+ oxidation of alpha-crystallin produces a 43,000 Da aggregate composed of A and B chains cross-linked by non-reducible covalent bonds.
The structure of a 43,000 Da aggregate generated from bovine lens alpha-crystallin polypeptides of 20,000 Da using Fe2+ catalyzed oxidation, was studied by sequence analysis of a 30,000 Da proteolytic fragment. Three polypeptide components were simultaneously sequenced in the electroblotted 30,000 Da fragment, corresponding to Phe114-Ser130... of the alpha A chain, and His 111-Ser135... and Ser 35-Leu49... of the alpha B chain. The relative proportions of the components suggests that the three polypeptides are present in equimolar amounts. It is concluded that the 30,000 Da fragment and, therefore, the 43,000 Da aggregate is constructed of both the A and B polypeptide chains covalently cross-linked with non-reducible bonds. At least one of these cross-links is present towards the carboxy-terminus of the A and B chains after Phe114 and His111, respectively.
Amino Acid Sequence↗
Phosphorylation of beta-crystallin B2 (beta Bp) in the bovine lens.
Three major 32P-labeled polypeptides were found in the soluble fraction of bovine lenses cultured in a medium containing [32P]orthophosphate. Two of the polypeptides corresponded to the phosphorylated A and B chains of alpha-crystallin. In this communication, the third polypeptide is now identified. This polypeptide is characterized by a molecular weight of 27,000 and a pI of 6.6, eluted exclusively in the beta Low fraction of a CL-6B gel filtration separation of lens soluble material, and could be further purified by DE52 anion exchange chromatography. The only 32P-labeled amino acid detected was phosphoserine. A single 32P-labeled peptide was observed after tryptic digestion and two-dimensional mapping. The amino acid sequence of the purified peptide is Gly-Ala-Phe-His-Pro-Ser-Ser. This sequence exactly matches the expected C-terminal tryptic fragment, residues 198-204, of the bovine beta-crystallin B2. The results of carboxypeptidase A digestion of the 32P-labeled peptide suggest that only Ser203 is phosphorylated. By using the catalytic subunit of the cAMP-dependent protein kinase, purified beta B2 was phosphorylated in vitro, generating a single 32P-labeled polypeptide with the identical pI as the phosphorylated polypeptide obtained from lens culture. On the basis of these data, the Mr 27,000 32P-labeled polypeptide is identified as the phosphorylated form of the beta-crystallin B2.
Animals↗
The disulfide content of calf gamma-crystallin.
The disulfide content of calf gamma-crystallin polypeptides has been investigated. The gamma-crystallin fraction of the soluble lens proteins was separated into five distinct polypeptides and characterized by isoelectric focusing, amino acid composition, and N-terminal sequence analysis to 25 residues. It has been demonstrated that 7 cysteines are present in gamma II, 4 to 5 cysteines in gamma IIIa, gamma IIIb, and gamma IV, and 6 cysteines in gamma I (beta s). Reduction of the total gamma-crystallin fraction with DTT resulted in an increase of approximately 1 to 1.5 mol of free SH per mole of protein. This increase in sulfhydryls was demonstrated to be contributed primarily by gamma II, the major polypeptide representing 50% of the total gamma-crystallin, which showed an increase of approximately 2.5 mol of sulfhydryl per mole of protein upon reduction. Insignificant disulfide content was present in gamma III and gamma IV and only a slight amount of disulfide was found in gamma I (beta s). The observed increase in sulfhydryl content upon reduction was not due to the presence of mixed disulfides of 2-mercaptoethanol, glutathione, or cysteine. The data are consistent with approximately 1 mol of intramolecular disulfide per mole of protein being present in gamma II. X-ray crystallography of gamma II has shown that the spatial location of Cys18 and Cys22 in the tertiary structure permits disulfide bond formation. Sequence analysis of the four major polypeptides of gamma-crystallin, gamma II, gamma IIIa, gamma IIIb, and gamma IV indicates that only gamma II has both Cys18 and Cys22. Cys18 is present in gamma IIIa, gamma IIIb, and gamma IV but Cys22 is replaced by His22. It is probable that the lack of disulfide in gamma IIIa, gamma IIIb, and gamma IV is due to the absence of Cys22.
Amino Acid Sequence↗
A method for the determination of inorganic phosphate in the presence of labile organic phosphate and high concentrations of protein: application to lens ATPases.
We present here an improvement in the classical molybdate method for inorganic phosphate determination. This method has high sensitivity, with 1 nmol of Pi giving an absorbance change of 0.060 A850 unit. It is highly reproducible and the color remains stable for at least 3.5 h. In addition the use of sodium dodecyl sulfate makes it possible to stop enzymatic reactions without organic phosphate hydrolysis. It also shows an extremely low interference by highly concentrated solutions of different origins. Of special interest is its high tolerance to protein, permitting as much as 50 mg/ml of human serum protein in the sample without precipitation or color interference. For these reasons, it proves to be very useful in the determination of ATPases in tissues such as the ocular lens with low specific activity.
Animals↗
Definition and comparison of the phosphorylation sites of the A and B chains of bovine alpha-crystallin.
The major phosphorylation sites of bovine alpha-crystallin Ser122 in the A chain, Ser59 and Ser43 and/or Ser45 in the B chain have been previously characterized. Further analysis of total alpha-crystallin, isolated from the cortex of calf lenses incubated in the presence of [32P]orthophosphate, demonstrated the presence of additional phosphorylation sites in both chains. At least three additional phosphorylation sites were found in the A chain and at least one in the B chain. These additional sites accounted for approximately 25% of the radioactivity incorporated in the protein. Two general sequences were found in most phosphorylation sites of both chains of alpha-crystallin: (Arg/Lys)-(X)-Pro-Ser and Ser-(X)-Ser-Leu-Ser. In spite of the 57% homology in the sequences of the A and B chains, the phosphorylation sites are located, in the A polypeptide, at the C-terminal third and in the B polypeptide, at the N-terminal third. The alignment of the regions containing the phosphorylation sites of both chains (C-terminal third of the A and N-terminal third of the B chain) revealed an unexpected similarity in the relative positions of the sites in each chain.
Amino Acid Sequence↗
Effectiveness of antibiotic prophylaxis according to the nutritional status in patients undergoing contaminated procedures.
The attempt to restrict as much as possible the use of the antibiotics in surgery is related with the recent introduction of short term antibiotic prophylaxis. In this study the possibility to select among patients undergoing contaminated procedures those who can benefit more from short term antibiotic prophylaxis was considered. With this aim the nutritional status of 302 patients according to three parameters: serum albumin, total iron binding capacity and weight loss, was assessed. Results obtained from short term antibiotic prophylaxis with clindamycin and gentamicin in 149 patients (53.6% malnourished) were compared with those obtained in 153 patients (49.6% malnourished) who were not treated peroperatively. Wound infection rate in patients who received antibiotic prophylaxis was 6% versus 15% in the group which did not receive antibiotics peroperatively (p less than 0.025). A significant reduction was observed in malnourished patients while in the well-nourished the decrease was not significant. Malnourished patients seem to gain a specific benefit from antibiotic prophylaxis.
Adolescent↗