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Biomedical subjects

A Guidi

Publications and source records attributed to A Guidi.

At least 19 recordsLinked to original sources
PubMed2006

Biochemical survey on episodic localized darkening in turkey deboned thigh meat packaged in modified atmosphere.

The color of food, especially meat and meat products, is a parameter that strongly influences consumer choice. In Italy, repeated cases of darkening in deboned thigh meat of male turkeys packaged in modified atmosphere (MAP; 80% 02, 20% CO2) have been reported. The pH, lipid oxidation (TBARS), heme proteins, and iron content were investigated in MAP samples of turkey males, females, and in oxygen-permeable film-packaged males. Furthermore, the absorbance spectrum (400 to 700 nm) of the meat extracts was analyzed to better delineate the evolution and characteristics of the darkening process. Results showed that darkening occurred only in males with higher content of total iron, independently of the content of heme proteins, which differs only between males and females. Furthermore, pH was higher in muscles taken as controls, with respect to muscles involved in the darkening, as well as in females. Finally, TBARS values were found to be higher in darkened regions than in not darkened ones, as well as in MAP samples with respect to oxygen-permeable film-packaged samples. These findings suggest that darkening occurrence might depend on kind of muscle, sex, and individual characteristics of the animals raised under the same breeding conditions.

Animals↗
PubMed2001

Endothelin-1 in human prostatic carcinoma treated with androgen withdrawal: an immunohistochemical study.

BACKGROUND: Various reports suggest a role for endothelin-1 in prostatic carcinoma. The objective of the current study was to evaluate the changes of the immunodetectable endothelin-1 in prostatic carcinomas characterized by different grades of regression due to total androgen withdrawal. METHODS: An immunohistochemical study was made on eleven prostatic carcinomas treated with neoadjuvant hormonal therapy for 3 months, followed by radical prostatectomy. Another ten specimens of untreated carcinomas were studied for comparison. An appraisal of androgen receptors was associated. A highly specific polyclonal antibody against endothelin-1 and a commercial monoclonal mouse antibody for androgenic receptors were used. RESULTS: In all cases, a prevalent quantity of androgenic receptor-positive tumor cells were present. Neoplastic cells of untreated carcinomas showed a strong and heterogeneous staining for endothelin -1. In unregressed areas of treated cases, the features of endothelin-1 and androgen-receptor staining were the same as those of untreated cases. In areas characterized by moderate histologic regression, the endothelin-1 staining became more heterogeneous. In areas of strong histologic regression, a diffuse membrane staining was often noted. Only in completely regressed cancer cells was a definite loss of immunodetectable endothelin-1 and androgenic receptors observed. CONCLUSIONS: Endothelin-1 is one of the proteins intrinsic to prostatic epithelial cells, both benign and malignant. In cases treated with androgen withdrawal, histologic regression is not uniform. In unmodified areas, immunodetectable endothelin-1 and androgenic receptors also are unmodified, thus suggesting some mechanism that substitutes for the action of androgen. Only neoplastic cells with complete histologic regression also lose androgenic receptors and endothelin-1, whereas the preserved immunostaining in deeply modified prostatic neoplastic cells seems to indicate that these cells still are potentially active.

Aged↗
PubMed2001

Red wine mitigates the postprandial increase of LDL susceptibility to oxidation.

The aim of the present study was to verify the extent of oxidative stress induced by a meal at plasma and LDL level, and to investigate the capacity of red wine to counteract this action. In two different sessions, six healthy men ate the same test meal consisting of "Milanese" meat and fried potatoes. The meal was taken either with 400 ml red wine or with an isocaloric hydroalcoholic solution. Oxidative stress at plasma level was estimated through the measure of ascorbic acid, alpha-tocopherol, protein SH groups, uric acid, and antioxidant capacity, measured before and 1 and 3 h after the meal. The change in the resistance of LDL to oxidative modification was taken as an index of exposure to pro-oxidants. The susceptibility to Cu(II)-catalyzed oxidation of baseline and postprandial LDL was measured as conjugated dienes formation, tryptophan residues, and relative electrophoretic mobility. The experimental meal taken with wine provoked a significant increase in the total plasma antioxidant capacity and in the plasma concentration of alpha-tocopherol and SH groups. Postprandial LDL was more susceptible to metal-catalyzed oxidation than the homologous baseline LDL after the ethanol meal. On the contrary, postprandial LDL obtained after the wine meal was as resistant or more resistant to lipid peroxidation than fasting LDL.

Adult↗
PubMed2001

Comparison of a conventional immunoassay (ELISA) with a surface plasmon resonance-based biosensor for IGF-1 detection in cows' milk.

Recombinant bovine somatotropin (rBST) treatment is adopted in dairy cows to augment milk yield. Previous studies showed that insulin-like growth factor-1 (IGF-1) is present in milk from cows treated with rBST. Since IGF-1 is a suspected carcinogen, its presence in milk for human consumption is potentially a health hazard. Therefore rBST use, still authorized in the United States, has been revoked in Canada and is under evaluation in the EU. The rising attention on IGF-1 presence in alimentary milk focused the necessity to develop specific, sensitive and rapid IGF-1 detection systems. We have developed a solid phase enzyme-linked immunoassay (ELISA) and also an automated surface plasmon resonance-based biosensor system (BIA-technology) for evaluating IGF-1 in fresh cow's milk. Hyperimmune polyclonal anti-IGF-1 antibodies were characterized with respect to their specific binding capacity to IGF-1. The results obtained with these two methods have been compared. This study shows the potential usefulness of the biosensor technology for biomolecular interaction analysis. The features of this technology (fully automated, measures in real time, sharpened yes/no response) offer several advantages compared to ELISA in the detection of compounds in fresh cows' milk (MURST 40%; CNR P.F. MADESS 2).

Animals↗
PubMed2000

Regio- and stereoselective cycloadditions of cyclic nitrones to maleic diamide forced in a peptide: synthesis of potent ligands of human NK-2 receptor.

The regioselectivity and the stereoselectivity induced by relatively small peptidomimetic maleic diamide 1 in cycloaddition reactions with cyclic nitrones 2-5 was studied. The high regio- and stereoselectivity observed, sensibly increased by nonpolar solvents, was the effect of a double-asymmetric induction produced by the nitrone substituent on the pseudopeptidic tether. A new class of potent human tachykinin NK-2 receptor ligands was synthesized.

Dipeptides↗
PubMed2000

Beer increases plasma antioxidant capacity in humans.

The positive association of a moderate intake of alcoholic beverages with a low risk for cardiovascular disease, in addition to ethanol itself, may be linked to their polyphenol content. This article describes the effect of acute ingestion of beer, dealcoholized beer, and ethanol (4.5% v/v) on the total plasma antioxidant status of subjects, and the change in the high performance liquid chromatography profile of some selected phenolic acids (caffeic, sinapic, syringic, and vanillic acids) in 14 healthy humans. Plasma was collected at various times: before (T0), 1 hour after (T1), and 2 hours after (T2) drinking. The study is part of a larger research planned to identify both the impact of brewing on minor components potentially present in beer and their metabolic fate in humans. Beer was able to induce a significant (P < 0.05) increase in plasma antioxidant capacity at T1 (mean +/- SD: T0 1,353 +/- 320 microM; T1 1,578 +/- 282 microM), returning close to basal values at T2. All phenolic acids measured in plasma tended to increase after beer intake (20% at T1, 40% at T2). Syringic and sinapic acid reached statistical significance (P < 0.05 by one-way analysis of variance-Fisher's test) at T1 and T2, respectively. Plasma metabolic parameters (glucose, total cholesterol, triglycerides, and uric acid) and plasma antioxidants (alpha-tocopherol and glutathione) remained unchanged. Ethanol removal impaired the absorption of phenolic acids, which did not change over the time of the experiment, accounting for the low (and not statistically significant) increase in plasma antioxidant capacity after dealcoholized beer drinking. Ethanol alone did not affect plasma antioxidant capacity or any of the antioxidant and metabolic parameters measured.

Journal Article↗
PubMed2000

Generalized eruptive keratoacanthoma (Grzybowski variant).

We describe a patient with generalized eruptive keratoacanthoma (KA) of Grzybowski showing the characteristic features of this extremely rare condition. Since the first description by Grzybowski in 1950, only 28 additional cases (including the present one) have been reported. This variety of KA most commonly affects patients during the fifth to seventh decade of life and appears as a generalized eruption of hundreds to thousands of follicular papules. The small pruriginous papules often have a keratotic centre and show microscopic features of KA. Marked facial involvement is characteristic and can lead to masked facies with ectropion, as in our patient. The course of the disease is chronic and the response to therapy is poor.

Acitretin↗
PubMed2000

Role of iodine in evolution and carcinogenesis of thyroid, breast and stomach.

The authors have hypothesized that dietary iodine (deficiency or excess) is associated with the development of some gastric and mammary cancers, as it is well-known for thyroid cancer. They report a short review of their own work and of the general literature on this correlation and on the antioxidant function of iodide in stomach, breast and thyroid. Thyroid cells phylogenetically derived from primitive iodide-concentrating gastroenteric cells which, during evolution, migrated and specialized in uptake and storage of iodine, also in order to adapt the organisms from iodine-rich sea to iodine-deficient land. Mammary cells also derived from primitive iodide-concentrating ectoderm. Stomach, breast and thyroid share an important iodide-concentrating ability and an efficient peroxidase activity, which transfers electrons from iodides to the oxygen of hydrogen peroxide and so protects the cells from damage caused by lipid peroxidation. The authors suggest that iodide might have an ancestral antioxidant function in all iodide-concentrating cells from primitive Algae to more recent Vertebrates. In Italy, gastric cancer is more frequent in farmers and in iodine-deficient populations, living in mountainous and hilly areas, than in fishermen. In the last two decades, Italian decrease of gastric cancer seems to be correlated more to the higher dietary consumption of iodine-rich fish rather than to consumption of fruit and vegetables, which indeed has decreased in Italy.

Adult↗
PubMed2000

Ambulatory blood pressure monitoring in passive smoking and atropine--response in healthy volunteers.

AIM: The purpose of this study is to assess the effects of intravenous atropine on blood pressure (BP), systolic BP (SBP) and diastolic BP (DBP), after exposure of healthy volunteers to environmental cigarette smoking. METHODOLOGY: Seventeen non-smoking healthy volunteers (11 men and six women), aged from 20 years to 50 years (mean age: 31.3 +/- 8.7), were studied. These subjects received atropine under two conditions: first, in a 60 cubic metres of indoor space unpolluted by cigarette smoke; and second, in the same environment but polluted by 35 ppm carbon monoxide concentration reached by cigarette combustion. BP of each subject was recorded every 15 minutes for two hours by using an Ambulatory Blood Pressure Recorder BR 102. RESULTS: Mean baseline BPs in a smoke-free environment and in a smoking environment were respectively 120 +/- 18 mmHg and 120 +/- 25 mmHg for systolic values, and 81 +/- 6 mmHg and 84 +/- 9 mmHg for diastolic values (P > 0.05). After administration of atropine, mean BPs were respectively 126 (+/- 24)/80(+/- 7) mmHg in a smoke-free environment, and 131 (+/- 14)/ 90(+/- 2) mmHg after exposure to passive smoking (P > 0.05, no statistical significance). CONCLUSION: Our observations showed that BP varied but without statistically significant changes after acute exposure to passive smoking. However, it is known that any increase in BP leads to higher cardiovascular risks.

Adult↗
PubMed1999

Nutritional assessment in head injured patients through the study of rapid turnover visceral proteins.

BACKGROUND & AIMS: Nutritional monitoring of rapid turnover visceral protein is important in the recognition of malnutrition in patients admitted to the Intensive Care Unit (ICU). We studied prealbumin and retinol-binding protein in patients who received three different kinds of artificial nutrition in order to evaluate the appropriateness of artificial nutrition. METHODS: 45 consecutive head injury patients received enteral (Group A), parenteral (Group B) or both enteral and parenteral nutrition (Group C) at random. We considered these parameters: prealbumin, retinol binding protein and nitrogen balance before (T1), after 3 (T2), 7 (T3) and 11 (T4) days after the beginning of study. Statistical analysis was performed with Kruskal-Wallis test and Bonferroni's t -test. RESULTS: Plasma prealbumin and Retinol binding protein (RBP) showed an increasing of basal values during the study period in all groups (<< 0.0001) and more significantly in group A (Enteral nutrition P < 0. 001 vs Total parenteral nutrition (TPN) and Enteral P<< 0.01 vs Enteral and parenteral nutrition). CONCLUSION: Data obtained in the present study indicate that a laboratory is essential for monitoring nutritional assessment and for checking the appropriateness of nutritional therapy. We found prealbumin to be the most sensitive measure and found it to be the test of choice for early assessment and intervention.

APACHE↗
PubMed1997

Detection and epitope mapping of immunoreactive human endothelin-1 using ELISA and a surface plasmon resonance-based biosensor.

A surface plasmon resonance-based biosensor (BIA technology) and enzyme-linked immunosorbent assays (ELISA) have been used for detecting and characterizing human endothelin (ET), a potent vasoactive 21 amino acid polypeptide. Antibodies produced against the isoform ET-1 and its C-terminal eptapeptide ET-1(15-21) have been characterized with respect to their binding capacity to the two isoforms ET-1 and ET-3, the non-secreted portion of the precursor molecule Big.ET-1(22-38), the C-terminal of ET-1, six analogues of ET-1(16-21) each containing a substitution with Ala of a single amino acid in positions 16-21, respectively, and three synthetic cyclic peptides mimicking the N-terminal portion of ET-1. Antibodies reacting with ET-1 also bound to ET-1(16-21) and, with less affinity, to ET-3 but did not cross-react with Big.ET-1(22-38). Ala substitution in positions 16, 17 and 19 of ET-1(16-21) hardly affected the antibody binding capacity of ET-1(16-21), whereas Ala substitution of Asp18, Ile20 and, in particular, Trp21, inhibited its immunoreactivity. The C-terminus thus represents an immunodominant epitope in ET-1 and is important for antibody binding. Epitope mapping using as antibody pairs polyclonal anti-ET-1 and monoclonal anti-ET-1(15-21) antibodies indicated the presence of another immunogenic domain in the N-terminal portion of the molecule. There was excellent agreement between the epitopes determined using ELISA and BIA analyses.

Amino Acid Sequence↗
PubMed1993

A new hypothesis: iodine and gastric cancer.

The authors have hypothesized that iodine-deficiency (I-def) or in some cases iodine-excess (I-excess) is associated with the development of gastric cancer. They report a short review of their own work and general literature on this subject in three fields: (1) epidemiology, where geographical and temporal correlations between territories with I-def (or I-excess) endemic goitre and high GC-death rate are reported; (2) immunology, where the possible correlations between I-def, immune-deficiency and GC are reported; and (3) thyroid gland and stomach correlations, both being embryologically derived from primitive gut and able to concentrate iodine. This ability is impaired by nitrates, thiocyanate, salt and by I-excess, which in fact can cause goitre. In our study I-def goitrous people have shown more atrophic gastritis than normal subjects. These data enable us to hypothesize that I-def or I-excess might constitute a new risk factor for gastric cancer, both by regulating gastric trophism and by antagonizing the action of those I-inhibitors (such as nitrates, thiocyanate and salt) previously studied as risk factors for gastric cancer.

Female↗
PubMed1990

Evidence for increased intracellular transport of m-sarcolysine (alkylating moiety) when combined with two amino acid analogs (PTT-119).

PTT-119 is an antineoplastic agent in which an alkylating moiety, m-sarcolysine, is linked to two amino acid analogs. Previous studies showed a higher "in vitro" cytotoxicity of PTT-119 when compared to free m-sarcolysine; the mechanisms of this enhanced activity are not completely understood. In this study we incubated peripheral blood cells from 8 chronic lymphocytic leukemia patients with both m-sarcolysine and equimolar concentrations of PTT-119, measuring the intracellular concentration of the alkylating moiety. We observed a significantly higher intracellular concentration of m-sarcolysine in cells incubated with the peptide-bound drug than with the free drug (58.3 +/- 39.6 versus 4.4 +/- 1.9 ng/10(6) cells; P = 0.013). This observation could explain the higher cytotoxic activity of PTT-119 and the lack of cross-resistance with melphalan.

Amino Acids↗