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Biomedical subjects

M Paoli

Publications and source records attributed to M Paoli.

33 records · Page 2Linked to original sources
PubMed1994

Characterization of recombinant horseradish peroxidase C and three site-directed mutants, F41V, F41W, and R38K, by resonance Raman spectroscopy.

Resonance Raman spectra are reported for recombinant horseradish peroxidase C (HRP-C*) and three protein variants prepared by in vitro refolding after Escherichia coli expression. The spectra of their FeII and FeIII forms and of their complexes with benzohydroxamic acid (BHA) were recorded at neutral pH. The residues mutated were on the distal [Phe41-->Trp or Val (F41W, F41V) and Arg38-->Lys (R38K)] side of the heme. The spectra give information on the spin and ligation states via the frequencies of the core size marker bands. No detectable modification in the enzyme structure or in the heme group has been observed in the wild-type recombinant HRP-C*. The FeIII forms of both the recombinant and the plant proteins show the coexistence of a 5-(5-cHS) and a 6-coordinate high-spin (6-cHS) heme, characterized by the anomalous frequencies of certain bands, namely, v3 and v10, which we attribute to a different degree of distortion of the heme planarity with respect to other heme proteins and model compounds, resulting from external forces such as steric contacts within the protein. This effect is partially relieved upon complexation with BHA or as a result of mutation. F41W and F41V are characterized by an increase in a 6-cHS form at the expense of the 5-cHS species, and the R38K by an increase in both the 6-c high-(HS) and low-spin (LS) hemes. The 6-cHS and -LS species are characterized by normal core size marker band frequencies. The FeII-His RR band is at 243 cm-1 in HRP-C*, the high frequency value being due to hydrogen-bonding interactions between the proximal His170 N delta and the carboxylate acceptor group on Asp247. Mutation at position 38 causes a downshift of 3 cm-1 in the v(Fe-Im) stretching mode, suggesting a weakening of the Fe-Im bond strength. By comparing the results obtained with HRP-C* mutants with those previously reported for the corresponding cytochrome c peroxidase (CCP) mutants, it appears that the distal heme pocket architecture is significantly different in the two peroxidases, although the hydrogen-bonding network coupling the distal and the proximal sides of the heme appears to be conserved. Mutations on the distal side dramatically affect the capability of the protein to bind BHA. F41W and R38K mutants do not bind the substrate, whereas the F41V variant shows a 2-fold increase in affinity.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗
PubMed1994

Spin state and axial ligand bonding in the hydroxide complexes of metmyoglobin, methemoglobin, and horseradish peroxidase at room and low temperatures.

Absorption and resonance Raman spectra using Soret excitation of alkaline metmyoglobin (metMb), methemoglobin (metHb), and horseradish peroxidase (HRP) were obtained at room and low temperature. At 298 K both metMb and metHb exhibit two isotope-sensitive bands assigned to high- and low-spin nu(Fe-OH) stretching modes, respectively, which are correlated with the spin-state population. The low-spin stretch occurs 60 cm-1 to higher energy than the corresponding high-spin vibration. When the temperature is lowered, only the low-spin species is observed. HRP exhibits at both 298 and 20 K only the low-spin nu(Fe-OH) stretching mode, which occurs 50 cm-1 to lower energy than the corresponding modes observed in the globins. This is explained in the context of a strong hydrogen bond between the hydroxyl ligand and the distal His42 and/or Arg38. Lowering temperature causes in all of the examined proteins a strengthening of the Fe-OH bond and a contraction of the core of about 0.01 A, as determined by the upshifting of the low-spin nu(Fe-OH) stretching mode and the core size marker bands. Both effects are ascribed to an increase of the packing forces.

Animals↗
PubMed1984

The ethological approach to the assessment of depressive disorders.

The ward behavior of 29 inpatients with a diagnosis of major depressive disorder and that of six mixed psychiatric patients was studied by means of an observational method derived from ethological techniques. By these means the occurrence of a wide variety of behaviors was monitored. Depressives before treatment differed from the same group after 4 week of treatment on several items: eye contact, exploration of the environment, verbal communication, and all social behaviors increased, whereas crying, nonsocial behaviors, and pathological behaviors decreased. The same behavioral categories distinguished depressed patients in baseline conditions from controls. When depressives were divided into responders and nonresponders on the basis of their Hamilton scores, behavior differences were notable only in the responders. Some behavioral patterns, such as the rate of social behaviors, were related to personality traits, which were assessed by means of the Maudsley Personality Inventory. Finally, some behavioral categories bore some weak, though significant, relationships to the Hamilton Rating Scale. The above results seem to indicate that a behavior pattern specific to depressive psychopathology does exist and closely resembles the one identified by the classical clinical description of depression. Ethological assessment may therefore be a useful tool in psychiatry, as it can evaluate the clinical picture in a different frame of reference from psychiatric interviews.

Adult↗
PubMed1979

[Anti-edema activity of injectable Venoruton in abdominal surgery].

The anti-oedema activity of an injectable drug (HR; active principle: 0-(beta-hydroxyethyl)-rutoside) was assessed in 60 gastric extrahepatic bile duct, and large intestine surgery patients (30 being used as controls). Gastroscopy (with biopsy), gastroduodenoscopy, colonoscopy (with biopsy) and radiological examination were usually performed on the 5th and 10th post-operative days. The drug showed significant therapeutic effects: rapid resolution of oedema, especially at the sutures, leading to early cicatrisation, canalisation and the prevention of dehiscence. Finally, duration of hospitalisation was less than in the untreated cases. The gastroscopic, radiographic and biopsy findings are considered to have shown clear evidence of the drug's action against oedema formation.

Adult↗
PubMed1977

[Post-amputation dehiscence. A problem resolved].

70 peripheral amputations of the lower extremities in arteriosclerotic and diabetic vasculopathics have been examined. In a number of cases, the postoperative period was complicated by dehiscence of the suture on the stump, with lengthening of hospitalization time, risk of infection in the underlying bone and thus further amputation. To solve this problem, dehiscence was treated with dermo-epidermal autografts to cover the missing tissue area. The dehiscence was cleaned with compresses of 2% amuchina associated with topical instillations of Lincomycin hydrochloride. The cure percentage after grafting was about 80%.

Aged↗
PubMedDate not supplied

Effect of glycemic control on the growth velocity and several metabolic parameters of conventionally treated children with insulin dependent diabetes mellitus.

To determine the effect of glycemic control on the growth velocity and several metabolic parameters of children with insulin-dependent diabetes mellitus (IDDM), 79 patients with IDDM, 45 females and 34 males with a mean chronological age of 8.4 +/- 3.0 years were followed over a 5-year period starting at the onset of diabetes. Glycemic control was assessed by measuring total glycosylated hemoglobin; children were divided into better controlled, GHb < 9%, 30 children (Group A) and worse controlled, GHb > or = 9%, 49 patients (Group B). Growth velocity was significantly lower, in the five years of follow up, in the worse controlled patients when compared to the better controlled subjects (4.8 +/- 1.6 vs 6.7 +/- 2.2 cm/yr after the first year and 5.0 +/- 2.0 vs 6.5 +/- 1.8 cm/yr after the fifth year, in group B and group A, respectively). Higher cholesterol (185.3 +/- 33.7 vs 158.8 +/- 39.5 mg/dl) and triglyceride levels (85.9 +/- 43.5 vs 71.0 +/- 37.4 mg/dl) were apparent in the worse controlled patients, when compared to the better controlled children. Insulin dose was not significantly different in the two groups (0.76 +/- 0.3 vs 0.84 +/- 0.4 U/kg/day in the 1st year and 0.9 +/- 0.3 vs 0.92 +/- 0.4 U/kg/day in the 5th year, in group B and A respectively). Although both groups received the same initial and long term training by our pediatric diabetes team, more frequent blood glucose monitoring, better record keeping and rotation of injection sites and more clinic visits were clearly noted in the better controlled group. Ketoacidotic episodes were more common in the worse controlled patients, while better controlled children had a higher number of hypoglycemic episodes. In conclusion, we have found poor glycemic control, as reflected by higher glycosylated hemoglobin levels, to affect the growth velocity and several metabolic parameters of children with diabetes followed for a five-year period. Other factors besides insulin dose and initial and subsequent diabetic education seem to play a role in their glycemic control.

Blood Glucose↗
PubMedDate not supplied

PCR analysis of the STR HUMF13A01 in a population sample of central Italy.

A population genetic study was carried out on an Italian sample of Central Italy (n = 159) using the short tandem repeat (STR) system HUMF13A01. After vertical electrophoresis in denaturing polyacrylamide gel, 11 alleles were found. No deviation from the Hardy-Weinberg equilibrium were observed. The power of discrimination (PD) was 0.91 and the chance of exclusion was 0.59. The allelic comparison with previous Italian population studies showed no significant difference.

Gene Frequency↗