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Biomedical subjects

A Conti

Publications and source records attributed to A Conti.

At least 217 records · Page 12Linked to original sources
PubMed1990

The complete primary structure of alpha-lactalbumin isolated from pig (Sus scrofa) milk.

The complete amino-acid sequence of pig alpha-lactalbumin has been determined. It was obtained by microsequencing of the native protein and the peptides derived after tryptic or cyanogen bromide cleavage. The tryptic peptides were separated by a rapid microbore HPLC method. Pig alpha-lactalbumin is 122 amino acids long and differs from the bovine homologue by 26 exchanged residues. Of the two prolines present in bovine alpha-lactalbumin, one has been deleted in the pig structure. All previously sequenced alpha-lactalbumins have shown glutamic acid at position 49, which is known to be the active site in the homologous lysozyme c structure. This residue is replaced by phenylalanine in pig alpha-lactalbumin indicating that the pig protein is the first alpha-lactalbumin with complete loss of all lysozyme functional residues.

Amino Acid Sequence↗
PubMed1990

Covalent structure of the minor monomeric beta-lactoglobulin II component from donkey milk.

The complete primary structure of the minor beta-lactoglobulin II component from donkey milk is presented. It has been established by amino-acid sequencing and mass-spectrometry analysis of intact protein and peptides obtained after enzymatic and chemical cleavages. The molecular mass and the pI of the protein are calculated to be 18,261 Da and 4.5 respectively. Despite the close structural similarity of the donkey and horse major beta-lactoglobulin I components, their minor beta-lactoglobulin II components show substantial differences in sequence. Most observed exchanges are clustered at residues 78-106 where only 6 amino-acid residues are conserved. The primary structure of donkey beta-lactoglobulin II reveals some unusual features of minor beta-lactoglobulins II and gives new light to the evolution of beta-lactoglobulins and other lipocalins involved in retinol binding or reproductive functions.

Amino Acid Sequence↗
PubMed1990

[Comparison of manual and mechanical anastomosis in colorectal surgery].

Between 1981 and 1989, 494 patients had anastomosis involving the colon or rectum (233 ileo-colonic, 156 colo-colonic, 96 colo-rectal and 9 ileo-rectal) in our Institute. 383 patients had manual anastomosis (Group 1), 111 patients had stapled anastomosis (Group 2). There was no statistically significant difference when comparing major anastomotic complications, reoperations and operative mortality of stapled and manual anastomoses. In group 1 a significant increase in complication was related to the presence of obstruction (p. less than 0.01), and to emergency surgery (p less than 0.01). In Group 2 malnutrition had a significant effect on anastomotic complications (p less than 0.01). Therefore, colonic obstruction, emergency surgery and malnutrition have a significant role in anastomotic complications, and particular care should be taken when these factors are present.

Aged↗
PubMed1990

[The importance of glycosylated plasma protein determination in the diagnosis of carbohydrate intolerance in obesity].

To evaluate the possible interest of the dosage of glycated plasma proteins in the diagnosis of glucidic intolerance, OGTT with determination of glycaemia and insulinaemia, HbA1c and fructosamine was determined in 6 normal and 35 obese subjects. On the basis of OGTT the subjects were subdivided into 20 obese with normal glucose tolerance, 7 with IGT and 8 with DM. In the comparison between all the subjects there was a significantly higher plasma fructosamine concentration in the obese with DM (p less than 0.001). No difference was noticed between the normal subjects and the other two classes of obese patients. This suggests that the evaluation of glycated plasma proteins is scarcely sure in a screening plan.

Adult↗
PubMed1989

Beta-endorphin and dynorphin mimic the circadian immunoenhancing and anti-stress effects of melatonin.

We have recently demonstrated that the pineal neurohormone melatonin can enhance immune reactivity in normal mice and counteract the effects of acute stress or corticosterone treatment on antibody production, thymus weight and anti-viral resistance. These remarkable immunopharmacologic effects of melatonin were abolished by naltrexone, suggesting an involvement of the endogenous opioid system. Here we compared the immunopharmacologic action of beta-endorphin, dynorphin 1-13, leu-enkephalin and metenkephalin with that of melatonin in restraint-stressed or prednisolone-treated mice and in normal nonstressed animals. We found that beta-endorphin and dynorphin 1-13 can mimic the immunoenhancing and antistress effect of melatonin. However, at variance with the pineal neurohormone, these opioids were effective in umprimed mcie, too. We found also that restraint stress or prednisolone treatment decreases the immunopharmacologic potency of beta-endorphin and augments that of dynorphin 1-13. In fact, at the doses used, beta-endorphin enhanced the antibody response in normal but not in stressed or prednisolone-treated mice, while dynorphin 1-13 was effective only in counteracting the effect of stress or prednisolone treatment. Most interestingly, all these effects proved to be dependent on the time of administration, i.e. showed a circadian rhythm in analogy with the effects of melatonin. Again, naltrexone abolished all the opioid effects, indicating that their action was exerted via opioid receptors. These findings have important scientific and practical implications.

Adjuvants, Immunologic↗
PubMed1989

Effect of oral zinc administration on prolactin and thymulin circulating levels in patients with chronic renal failure.

High serum PRL and low zinc (Zn) levels are common findings in patients with chronic renal failure (CRF); in such patients serum Zn concentrations have been reported to be inversely correlated to serum PRL levels. Moreover, Zn regulates both thymus growth and the biological activity of the thymic hormone thymulin, and PRL-thymic interrelationships have been described. To determine whether hypozincemia alters serum PRL and plasma thymulin concentrations in CRF, 9 men with CRF treated by chronic hemodialysis were given 400 mg/day Zn sulfate, orally (4.96 meq/day Zn), for 6 months. Before treatment, serum PRL levels were significantly higher (P less than 0.001) in these patients than in normal men [mean, 28.7 +/- 20.7 (+/-SD) vs. 7.5 +/- 3.7 micrograms/L], and their serum PRL response to TRH (200 micrograms, iv) was impaired (mean maximal percent increase, 38.2 +/- 10.9 vs. 641 +/- 335; P less than 0.001). The plasma Zn-bound bioactive thymulin titer (1.3 +/- 0.7 1/log2), total thymulin titer (Zn-bound plus Zn-unbound forms, 2.1 +/- 0.8 1/log2), and serum Zn (13.1 +/- 2.4 mumol/L) were lower (P less than 0.001) in men with CRF than in normal men. Zn therapy did not induce any significant change in basal and TRH-stimulated serum PRL levels, while serum Zn levels significantly increased, reaching the normal range after the first week of treatment (17.8 +/- 6.3 mumol/L). Plasma total thymulin increased rapidly, reaching normal levels after 1 week, but Zn-bound thymulin increased modestly during the first month of treatment and more after 3 and 6 months of treatment. There was no age-related difference in plasma thymulin levels during therapy. We conclude that oral Zn administration in patients with CRF significantly increases both total and Zn-bound thymulin, but does not modify basal and TRH-stimulated serum PRL levels. The observation that Zn supplementation markedly increased plasma thymulin levels in uremic patients suggests that Zn is a potent stimulus for thymic hormone synthesis, and it can reverse the age-related diminution of thymic activity in CRF patients.

Adult↗
PubMed1989

Isolation and complete primary sequence of a new ovine wild-type beta-lactoglobulin C.

A new wild type of beta-lactoglobulin has been identified in the milk of sheep. It has been designated as ovine beta-lactoglobulin C. Its primary structure has been determined by direct protein microsequencing of intact protein and RP-HPLC-derived tryptic peptides. The new beta-lactoglobulin C is a subtype of ovine beta-lactoglobulin A with a single exchange Arg-Gln at position 148. This exchange may influence polymerisation of beta-lactoglobulin since in the crystal structure of orthorhombic bovine beta-lactoglobulin, residues 145-150 constitute a short beta-sheet region involved in dimer formation by pairing of dyad-related strands.

Amino Acid Sequence↗
PubMed1989

Factors influencing prognosis of gastric cancer after curative resection.

Four hundred eighty eight patients with gastric cancer were admitted to the Department of III Clinica Chirurgica of the University of Bologna-Italy; 451 patients underwent surgery: there were 17 deaths with an operative mortality rate of 3.8%. Only 286 curative resections were performed 252 sub-total gastrectomies and 34 total gastrectomies. The purpose of this paper is to define the prognostic role of some clinical and pathological variables in patients with carcinoma of the stomach who underwent curative resection. The hospital records of 229 patients submitted to curative resection between 1969 and 1982 were retrospectively reviewed. Fifty two patients were lost to follow-up study and 4 died for post-operative complications. The variables analyzed included: age (greater than 65 years, less than 65 years), sex, time of onset of clinical symptoms (greater than 6 months, less than 6 months), site of cancer (lower, two thirds, upper), size (greater than 3 cm, less than 3 cm), gross appearance (ulcerating, non ulcerating), histologic type (intestinal, diffuse), invasion of the gastric wall (T1-T2 vs. T3-T4), nodal status (negative, positive), stage (S1-S2 vs. S3-S4). The statistical significance of the results was calculated using chi 2 test and comparing survival at 1, 3 and 5 years. Of the variables selected only six (age greater than 65 years, size greater than 3 cm, diffuse histologic type, degree of the gastric wall invasion, positive nodal involvement, stage 3-4) were validated by statistic evaluation, whereas the others lost their prognostic relevance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Is hyperbilirubinemia a risk factor in biliary surgery?].

The Authors, by means of a retrospective analysis of the patients operated on for biliary tract diseases (obstructive or not), evaluated the role of the serum bilirubin level as risk factor in this type of surgery. They show data about 474 patients divided into two groups on the basis of serum bilirubin level, examine mortality and morbidity rates also as a function of the age and analyze the results with the chi-square test. The Authors conclude that the serum bilirubin level have no statistically significant influence on the mortality and the morbidity rates, while elderly age results to be a risk factor.

Aged↗
PubMed1988

The influence of heparin on the wound healing response to collagen implants in vivo.

The biologic response to fibrillar collagen (collagen) and fibrillar collagen plus heparin (collagen/heparin) implants have been compared in the rat subcutaneous and guinea pig dermal wound models. The reconstituted bovine dermal collagen implants were injected subcutaneously in rats at concentrations ranging from 18 to 30 mg/ml and in volumes ranging from 0.5 to 1.0 ml. The biologic response to the collagen implants alone was characterized by a transient invasion of a modest number of inflammatory cells within the first three days of implantation that was followed by limited fibroblast invasion into the peripheral 1/3 of the implant during the course of the next three to four weeks. Occasionally, blood vessels were observed to invade the peripheral regions of the implant. The degree (number) and extent (depth) of cell invasion were inversely related to initial collagen implant concentration. Addition of heparin (0.3-20 micrograms/mg collagen) to these implants resulted in a significant dose-dependent increase in the degree and extent of fibroblast invasion. Radiolabeling studies showed that the collagen and collagen/heparin implants were cleared from the subcutis at identical rates. Implantation of these formulations in a guinea pig dermal wound model was also performed, using a semi-occlusive wound dressing (Opsite) to maintain the implant in the wound site. The fibrillar collagen implant alone was pushed upward by developing granulation tissue at the base of the wound and served as a support for epidermal cell migration, proliferation, and differentiation as wound closure proceeded. The implant was slowly invaded and turned over as granulation tissue developed from the base and margins of the wound bed. The inclusion of heparin in these implants resulted in a significantly different pattern of wound healing. The collagen/heparin implants histologically presented a more broken-up or porous appearance following implantation, which was associated with a greater degree of penetration of developing granulation tissue into the implant itself as compared to the collagen implants. Radiolabeling studies revealed that clearance rates of implants with and without heparin from wound sites were similar, as noted in the rat subcutis. Laser doppler flowmetry studies suggested that the heparin--containing implants were more vascular than control wound sites or sites treated with collagen alone.

Animals↗
PubMed1988

Microanalysis of the amino-acid sequence of monomeric beta-lactoglobulin I from donkey (Equus asinus) milk. The primary structure and its homology with a superfamily of hydrophobic molecule transporters.

The complete primary structure of donkey beta-lactoglobulin I was determined by pulsed-liquid phase microsequencing of tryptic peptides. The protein has been isolated in monomeric form and it corresponds to monomeric beta-lactoglobulin of type I. With the inclusion of donkey beta-lactoglobulin I there are 13% common residues amongst the members of the beta-lactoglobulin family. Donkey beta-lactoglobulin I is homologous to the retinol-binding protein, bilin-binding protein and five other proteins belonging to the new superfamily of hydrophobic molecule transporters. A rapid method for peptide isolation and the strategy for microsequencing of this protein have been described.

Amino Acid Sequence↗
PubMed1988

The primary structure of donkey (Equus asinus) lysozyme contains the Ca(II) binding site of alpha-lactalbumin.

The complete primary structure of donkey lysozyme has been established by pulsed liquid-phase sequencing of tryptic and chymotryptic peptides isolated by RP-HPLC. The positions of the Cys residues were identified by labeling the Cys residues with DABIA-reagent. Donkey lysozyme is a c-type lysozyme which is 129 amino acids long. It exhibits 50% homology to the human protein. We observe the full Ca(II) binding site suggested for the homologous alpha-lactalbumines. Although horse lysozyme has been reported to contain asparagine in position 61, which was in conflict with the three-dimensional structure of lysozyme, all other known c-type lysozymes, including donkey, contain Ser 61.

Amino Acid Sequence↗
PubMed1988

[Significance of QT interval as a premonitory sign of severe ventricular arrhythmia in the early phase of myocardial infarct].

In order to evaluate the relationship between the length of the corrected QT interval (QTc), calculated according to Bazett's formula, and the incidence of ventricular fibrillation (V.F.) in the early phase of acute myocardial infarction (A.M.I.), the QTc interval was measured in 494 patients (mean age 66.42 +/- 11 years; 357 males and 137 females) assisted by the Mobile Coronary Care Unit of Florence. A.M.I. was anterior in 269 patients, inferior in 177 and non-Q in 34. The QTc interval measured on E.C.G. was recorded within the first hour after the onset of pain in 203 patients and between the first and sixth hour in 291 patients. The QTc interval was also measured in a control group consisting of 96 non A.M.I. patients with no history of coronary artery disease. 43 patients with A.M.I. (8.6%) developed V.F. in the first 24 hours. It was observed that: 1) The QTc interval of patients with A.M.I. was longer than that in patients without A.M.I. (432 +/- 34.18 msec. versus 425.37 +/- 25, p less than 0.02). 2) The QTc interval of patients with A.M.I. who developed V.F. was the same as that of patients with A.M.I. but without V.F., (432.6 +/- 34.18 msec. versus 438.11 +/- 34.13, N.S.). 3) 60.46% of patients with V.F. had a value of QTc less than 440 msec.; the incidence of QTc greater than 440 msec. showed no difference in the groups with or without V.F. (41.86% versus 41.11%). 4) The QTc interval length was greater in anterior than in inferior A.M.I. (435.12 +/- 30.81 msec. versus 429.05 +/- 34.5, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Role of the pineal gland in immunity. III. Melatonin antagonizes the immunosuppressive effect of acute stress via an opiatergic mechanism.

We have recently demonstrated that the pineal neurohormone melatonin exerts important immunoregulatory functions. We now report that exogenous melatonin counteracts completely the effect of acute anxiety-restraint stress on thymus weight and antibody response to sheep red blood cells (SRBC). In addition, administration of melatonin in the evening prevented paralysis and death of mice infected with sublethal doses of encephalomyocarditis virus (EMCV) after acute stress. The anti-stress activity of melatonin was present in mice injected with T-dependent antigens, and it was abolished by the contemporary administration of the specific opioid-antagonist naltrexone. This suggests that melatonin exerts its remarkable anti-stress effect on antigen-activated cells via an opiatergic mechanism. These findings have important implications at both basic and clinical levels. They provide a new approach to a possible physiological 'up-regulation' of the immune response under virus- and/or stress-related immunosuppression.

Acute Disease↗