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Biomedical subjects

M Bolognesi

Publications and source records attributed to M Bolognesi.

247 records · Page 14Linked to original sources
PubMed1978

Crystallographic studies on D-amino acid oxidase.

D-amino acid oxidase, a flavoprotein from hog kidneys, has been crystalized in two different forms. Orthorhombic prisms have been obtained from the enzyme.benzoate complex at pH 8.3; the space group is C2221 and the cell dimensions are a = 325A, b = 138.8 A, c = 200 A. At lower pH values, the enzyme crystallizes in trigonal prisms with a = b = 116.0 A, c = 399 A, space group P3112 or its enantiomorph. The two crystal forms have been obtained at 28 degrees C while at 4 degrees C only weak evidence of crystallization has been detected. In both crystalline modifications, the protein is highly associated.

D-Amino-Acid Oxidase↗
PubMed1976

Duration and complications of multiple pregnancies.

Multiple pregnancies reach full term only in a remarkably lower percentage with respect to single pregnancies. Even in the case of multiparae, delivery occurs some three weeks before term. Complications may concern either pregnancy and puerperium or delivery. The former include (1) abortions, especially frequent in the case of monoplacental and monochorial pregnancies; (2) rarer events, such as hydramnios, placenta praevia, association of an ectopic pregnancy with an intrauterine pregnancy, molar degeneration of one egg with normal development of the other; (3) gestoses of the first and second trimester, more frequent than in single pregnancy; and (4) higher incidence, during puerperium, of hemorrhage, phlebitis, and uterine subinvolution. With respect to delivery, normal delivery only occurs in approximately 70% of twin pregnancies, the period of dilatation being generally longer than normal. Better assistance and techniques during labor and especially in the interval between delivery of first and second twin have remarkably reduced the higher mortality rate, especially for the second twin.

Abortion, Spontaneous↗
PubMedDate not supplied

Crystal structure of the bovine alpha-chymotrypsin:Kunitz inhibitor complex. An example of multiple protein:protein recognition sites.

The crystal structure of bovine alpha-chymotrypsin (alpha-CHT) in complex with the bovine basic pancreatic trypsin inhibitor (BPTI) has been solved and refined at 2.8 A resolution (R-factor = 0.18). The proteinase:inhibitor complex forms a compact dimer (two alpha-CHT and two BPTI molecules), which may be stabilized by surface-bound sulphate ions, in the crystalline state. Each BPTI molecule, at opposite ends, is contacting both proteinase molecules in the dimer, through the reactive site loop and through residues next to the inhibitor's C-terminal region. Specific recognition between alpha-CHT and BPTI occurs at the (re)active site interface according to structural rules inferred from the analysis of homologous serine proteinase:inhibitor complexes. Lys15, the P1 residue of BPTI, however, does not occupy the alpha-CHT S1 specificity pocket, being hydrogen bonded to backbone atoms of the enzyme surface residues Gly216 and Ser217.

Animals↗
PubMedDate not supplied

Binding of the soybean Bowman-Birk proteinase inhibitor and of its chymotrypsin and trypsin inhibiting fragments to bovine alpha-chymotrypsin and bovine beta-trypsin. A thermodynamic study.

The effect of pH and temperature on the apparent association equilibrium constant (Ka) for the binding of the soybean Bowman-Birk proteinase inhibitor (BBI) and of its chymotrypsin and trypsin inhibiting fragments (F-C(p), F-T(p) and F-T(t), respectively) to bovine alpha-chymotrypsin (alpha-chymotrypsin) and bovine beta-trypsin (beta-trypsin) has been investigated. On the basis of Ka values, the proteinase inhibitor affinity can be arranged as follows: alpha-chymotrypsin: BBI approximately beta-trypsin:BBI approximately beta-trypsin:F-T(t) approximately beta-trypsin:F-T(p) much greater than alpha-chymotrypsin:F-C(p). F-C(p), F-T(p) and F-T(t) do not inhibit beta-trypsin and alpha-chymotrypsin action, respectively. On lowering the pH from 9.5 to 4.5, values of Ka for BBI, F-C(p), F-T(p) and/or F-T(t) binding to alpha-chymotrypsin and beta-trypsin decrease, thus reflecting the acid-pK shift of the invariant His57 catalytic residue from 7.0, in the free enzymes, to 5.2, in the proteinase:inhibitor complexes. Considering the known molecular models, the observed binding behaviour of BBI, F-C(p), F-T(p) and F-T(t) was related to the inferred stereochemistry of the proteinase:inhibitor contact regions.

Animals↗
PubMedDate not supplied

Binding of the recombinant proteinase inhibitor eglin c from leech Hirudo medicinalis to serine (pro)enzymes: a comparative thermodynamic study.

The binding of the recombinant proteinase inhibitor eglin c from the leech Hirudo medicinalis to serine (pro)enzymes belonging to the chymotrypsin and subtilisin families has been investigated from the thermodynamic viewpoint, between pH 4.5 and 9.5 and from 10 degrees C to 40 degrees C. The affinity of eglin c for the serine (pro)enzymes considered shows the following trend: Leu-proteinase [the leucine specific serine proteinase from spinach (Spinacia oleracea L.) leaves] greater than human leucocyte elastase congruent to human cathepsin G congruent to subtilisin Carlsberg congruent to bovine alpha-chymotrypsin greater than bovine alpha-chymotrypsinogen A congruent to porcine pancreatic elastase congruent to bovine beta-trypsin. The serine (pro)enzyme-inhibitor complex formation is an entropy-driven process. On increasing the pH from 4.5 to 9.5, the affinity of eglin c for the serine (pro)enzymes considered increases thus reflecting the acid pK shift of the invariant hystidyl catalytic residue from approximately to 6.9 in the free serine proteinases and bovine alpha-chymotrypsinogen A to congruent to 5.1 in the serine (pro)enzyme-inhibitor complexes. Considering the known molecular models, the observed binding behaviour of eglin c was related to the inferred stereochemistry of the serine (pro)enzyme-inhibitor contact regions.

Animals↗
PubMedDate not supplied

Nerve globins in invertebrates.

The expression of nerve hemoglobins in invertebrates is a well-established fact, but this occurrence is uncommon. In the species where nerve globins occur, they probably function as an oxygen store for sustaining activity of the nerves during anoxic conditions. Although invertebrate nerve globins are functionally similar with respect to O2 affinity, they are by no means uniform in structure and can differ in size, cellular localization and heme-coordination. The best-studied nerve globin is the mini-globin of Cerebratulus lacteus, which belongs to a class of globins containing the polar TyrB10/GlnE7 pair in the distal pocket. The amide and phenol side chains normally cause low rates of O2 dissociation and ultra-high O2 affinity by forming strong hydrogen bonds with bound ligands. Cerebratulus hemoglobin, however, has a moderate O2 affinity, due to the presence of a third polar amino-acid in its active site, ThrE11, which inhibits hydrogen bonding to bound oxygen by the B10 tyrosine side chain.

Animals↗
PubMedDate not supplied

[Assessing the chemical cross-reaction from cefixime and some nonsteroidal anti-inflammatory agents in a soluble formulation].

The presence of chemical cross-reactivity between drugs may be an underestimated factor, responsible for decreased bio-availability of a drug active component(s); the absence of chemical cross-reactivity between drugs is undoubtedly the prerequisite for their simultaneous co-administration. Here, by means of thin layer chromatography, we show that cefixime, a third generation oral cephalosporin, does not display chemical reactivity versus a series of non-steroidal antiinflammatory agents. The four compounds tested can therefore be safely soluted together with the cephalosporin.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

[Promoting physical activity in overweight and obese patients: counseling in primary care from Italy (Cesena, 2002--2003)].

Lack of physical activity and obesity represent important public health problems. The objectives of the current study is to evaluate the effects of a counseling intervention (the PACE protocol) conducted by general practitioners and designed to motivate persons who are overweight or obese to increase their levels of physical activity. The counseling was offered 145 patients with a BMI > or =27 who were seen between May 2002 and April 2003 in the offices of 10 general practioners. The intervention, which lasted 3-5 minutes, was conducted during routine visits, based on the Prochaska-DiClemente model of behavioral change. Changes in the motivation of the patients to engage in physical activity and actual changes in levels of activity were measured, as were BMI and abdominal circumference. The median followup was 9 months. Among the 145 eligible patients, 103 (71%) agreed to particpate. Six months following the counselling, there was a significant change in both the motivational status and physical activity of the group, and they experienced significant decreases in BMI and abdominal circumference. Counseling using the PACE model appears to positively influence levels motivation and of physical activity in those patients who agreed to participate. Further studies should be conducted to evaluate the effectiveness of this strategy in other settings and the public health benefits of such counseling.

Adolescent↗
PubMedDate not supplied

[Hirudin inhibition of human thrombin activity].

Thermodynamics and kinetics for hirudin binding to human alpha-, beta- and gamma-thrombin, under experimental conditions which mimic the in vivo conditions (i.e., pH = 7.35, T = 37.0 degrees C, I = 0.1 M), indicate that the inhibitor specificity for the three species of the enzyme is different. Such a finding agrees with the human thrombin:hirudin binding geometry as revealed by X-ray crystal studies. From the therapeutic viewpoint, thermodynamics and kinetics here reported indicate that the inhibitory activity of hirudin in vivo is more effective than that shown by antithrombin III, which is generally considered the most important plasma thrombin inhibitor.

Hirudins↗
PubMedDate not supplied

Apparent subunit heterogeneity of NAD-dependent glyceraldehyde-3-phosphate dehydrogenase from spinach leaves.

NAD dependent glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) from spinach leaves has been previously investigated: the enzyme, homogeneous on conventional chromatography and analytical disc electrophoresis, shows on denaturing condition, non identical subunits of 37,000 and 14,000 daltons which have been separated in equimolar amounts after sodium dodecyl sulphate treatment (Speranza and Gozzer, 1978). Affinity chromatography carried out on these enyzme preparations allowed to separate a fully active enzyme of 150,000 daltons M.W. from a protein of 70,000 daltons M.W. which is devoid of glyceraldehyde-3-phosphate dehydrogenase activity: the purified enzyme shows 37,000 daltons subunits, while the second protein is made up of 14,000 daltons subunits. It is also reported that the 70,000 daltons protein could be separated from the enzyme by selective crystallization in the presence of organic solvents. It is concluded that the NAD-dependent glyceraldehyde-3-phosphate dehydrogenase from spinach leaves, as the homologous enzyme from other sources, is a tetramer of 37,000 daltons subunits.

Chromatography, Affinity↗