Search PubMed⌕ Search

Biomedical subjects

M Seccia

Publications and source records attributed to M Seccia.

At least 37 records · Page 2Linked to original sources
PubMed1994

Tyrosine hydroxylase activity in the locus coeruleus of conscious rats: differences with the anesthetized rats.

Microdialysis was used to estimate in vivo tyrosine hydroxylase (TH) activity in locus coeruleus (LC) of conscious rats. An aromatic amino acid decarboxylase inhibitor, difluoromethyl-DOPA (DFMD), was perfused through the dialysis probe and the DOPA accumulating in dialysates was measured. A 3 h perfusion of a 6 x 10(-4) mol/l DFMD solution was needed to obtain measurable levels of DOPA in LC dialysates: a linear increase in DOPA concentrations was first observed and, then, a steady state. DOPA disappeared completely after inhibition of TH by alpha-methyl-p-tyrosine, showing that it reflects TH activity. The DFMD perfusion needed in this study was six times higher in concentration and three times longer in duration than the one required in a previous study we performed in LC of anesthetized rats. Furthermore, TH activity was found lower than the one we previously reported. We conclude that these differences could be explained by the effects of halothane anesthesia on DFMD and DOPA degradation and/or on LC neurons TH activity itself.

Anesthetics↗
PubMed1994

Autoantibodies against oxidatively-modified LDL in uremic patients undergoing dialysis.

Target-specific oxidation processes in LDL generate molecular epitopes that are more atherogenic than the native forms and are able to elicit an immunological reaction leading to the formation of anti-oxLDL autoantibodies (oxLDL-Ab) that may participate in the overall process of atherogenesis. Thus, the detection of oxLDLAb, in addition to mirroring the occurrence of in vivo LDL oxidation, will give valuable information on the occurrence of this immune response. Plasma oxLDLAb (IgG and IgM) were measured in 72 control subjects (CS) and in 80 patients with chronic renal failure (CRF), undergoing repetitive hemodialysis (N = 56) or peritoneal dialysis (N = 24), with an ELISA method using native LDL, CuSO4-oxidized LDL (oxLDL) or malondialdehyde-derivatized LDL (MDA-LDL) as antigens. To monitor cross reactivity of the antibodies detected with other oxidatively-modified proteins, human serum albumin (HSA) and MDA-derivatized HSA (MDA-HSA) were also employed as antigens. The antibody titer was calculated as the ratio of antibodies against modified versus native proteins. CRF patients had an antibody ratio significantly higher than CS as concerning anti-oxLDL IgG (1.39 +/- 0.36 vs. 1.05 +/- 0.3, P < 0.05) and IgM (2.15 +/- 0.75 vs. 1.43 +/- 0.43, P < 0.01), and anti-MDA-LDL IgG (3.05 +/- 0.74 vs. 2.04 +/- 0.42, P < 0.01) and IgM (5.55 +/- 1.79 vs. 2.9 +/- 0.85, P < 0.01). The anti-MDA-HSA antibody titer was also higher in CRF patients than in CS (2.49 +/- 0.5 vs. 1.46 +/- 0.39, P < 0.01 for IgG and 2.80 +/- 1.03 vs. 1.26 +/- 0.43, P < 0.01 for IgM).(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehydes↗
PubMed1993

Exposure of beta H-crystallin to hydroxyl radicals enhances the transglutaminase-susceptibility of its existing amine-donor and amine-acceptor sites.

beta H-crystallin was exposed to radiolytically generated hydroxyl radicals at defined radical concentrations, and its capacity to act as an amine-acceptor substrate and as an amine-donor substrate for transglutaminase were investigated. [14C]Methylamine was used as a probe for labelling amine-acceptor sites; a novel biotinylated hexapeptide was used to label amine-donor sites. The results demonstrate that both primary amine incorporation and hexapeptide incorporation by transglutaminase are considerably increased after oxidative attack on the crystallin. The identity of the labelled subunits was established, and it is shown that, in both cases, this increased incorporation is not due to the production of new substrates, but that the existing incorporation sites become more susceptible. Moreover, using the newly developed probe, we could identify, for the first time, the major crystallin subunits active as amine-donor substrates (both before and after treatment) to be beta B1-, beta A3- and beta A4-crystallin. These data support the proposal that oxidative stress and transglutaminase activity may be jointly involved in the changes found in lens crystallins with age and in the development of cataract.

Amines↗
PubMed1993

Eosinophilic gastroenteritis: possible role of sonography in diagnosis and follow-up.

Eosinophilic gastroenteritis (EGE) is a rare disease of unknown etiology. The clinical and radiological diagnoses have to be confirmed by histological examination of biopsy specimens. The authors now present a case of a 19-year-old man with recurrent epigastric pain and vomiting, whose sonographic features and eosinophilia suggested the diagnosis of EGE, which was subsequently confirmed by histology. Sonographic follow-up permitted an effective evaluation of the evolution of the disease under steroid therapy.

Adult↗
PubMed1992

Subcutaneous seeding after percutaneous ethanol injection of liver metastasis.

A 72-year-old cirrhotic woman underwent percutaneous ethanol injection treatment of a liver metastasis of unknown origin. A subcutaneous metastasis developed at the site of the punctures. Needle track seeding is a rare complication of fine-needle biopsy but has never--to the authors' knowledge--been reported after percutaneous ethanol injection. The possible causes of this complication are discussed.

Adenocarcinoma↗
PubMed1992

[The prevention of postoperative deep venous thrombosis with heparan sulfate per os. A controlled clinical study vs. heparin calcium].

The paper reports the results of a randomised study carried out on a pool of 100 patients undergoing surgery in order to assess the efficacy and tolerability of orally administered heparan sulfate versus heparin calcium in the prevention of postoperative deep-vein thrombosis. Despite the limits of oral administration, heparan sulfate is indicated in the pharmacological prevention of postoperative deep-vein thrombosis.

Administration, Oral↗
PubMed1991

Exposure of beta L-crystallin to oxidizing free radicals enhances its susceptibility to transglutaminase activity.

1. The effects of free radicals on the capacity of beta L-crystallin to act as a substrate for the enzyme transglutaminase were investigated. 2. beta L-Crystallin was exposed to defined radical species that were generated radiolytically, and transglutaminase activity, using the modified protein as substrate, was subsequently measured by monitoring the incorporation of [14C]putrescine. 3. Exposure of beta L-crystallin to hydroxyl radicals, thymine peroxyl radicals and acetone peroxyl radicals at concentrations of up to 135 microM increased the capacity of the protein to incorporate putrescine. With higher concentrations of these radicals this capacity of beta L-crystallin to act as a transglutaminase substrate declined to control levels or lower. 4. Superoxide radicals were inactive in this regard; hydroperoxyl radicals were active only at high concentrations. 5. It has previously been suggested that changes in the crystallins that occur during aging and with cataract may be due to oxidative reactions and to transglutaminase activity. This study suggests that these phenomena may be considered together rather than separately.

Animals↗
PubMed1990

Perineal colostomy and electrostimulated gracilis "neosphincter" after abdomino-perineal resection of the colon and anorectum: a surgical experience and follow-up study in 47 cases.

A series of 47 patients undergoing abdomino-perineal resection of the distal colon and anorectum and construction of a continent perineal colostomy using electrostimulated gracilis muscle is described. External and implanted pulse generators have both been used. An analysis of complications and oncological data are reported. There was no operative mortality. The incidence of complications, divided into three classes, mild (62%), moderate (27%) and severe (11%), has not significantly altered the functional results, with the exception of early ischaemia of the colonic stump in two cases. During the first 22 cases, no preoperative oncological staging was performed. In the last 23 patients endorectal ultrasonography and CT scanning were carried out. Functional results were evaluated by electromanometry, electromyostimulation and dynamic defaecography. Clinical data assessed postoperatively showed good function in 65% of cases, fair in 22.5% and poor in 12.5%. The quality of life in 15 patients with a perineal colostomy and electrostimulated gracilis was significantly better than in 15 patients having an abdomino-perineal resection without gracilis plastic reconstruction.

Adult↗
PubMed1990

In vivo monitoring of catecholaminergic metabolism in the C1 region of rat medulla oblongata: a comparative study by voltammetry and intracerebral microdialysis.

In vivo voltammetry or microdialysis was used to monitor catecholaminergic metabolism in the C1 region of the ventrolateral medulla oblongata of anesthetized rats. In vivo voltammetry allowed the recording of a catechol oxidation current (CA.OC) peak in this region. This CA.OC was suppressed after inhibition of monoamine oxidase by pargyline or after inhibition of tyrosine hydroxylase by alpha-methyl-p-tyrosine and was markedly increased after blockade of dopamine-beta-hydroxylase by FLA 63. Similar results were found when intracerebral microdialysis coupled with HPLC and electrochemical detection was used to measure the concentration of 3,4-dihydroxyphenylacetic acid (DOPAC) in the dialysates obtained from the C1 region: The changes in CA.OC and DOPAC concentration in the dialysates exhibited very similar kinetic characteristics in the three pharmacological experiments. These results support the involvement of DOPAC as a major component of the electrochemical signal recorded by voltammetry in the C1 group of adrenergic neurons.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

Increased susceptibility to transglutaminase of eye lens proteins exposed to activated oxygen species produced in the glucose-glucose oxidase reaction.

In order to test whether a mild oxidative stress could promote the transglutaminase damaging effect on eye lens proteins, total lens soluble proteins and purified beta L-crystallin have been exposed to H2O2 slowly produced by the glucose-glucose oxidase reaction. Soon after the pretreatment, the substrate capacity of the lens proteins for an exogenous transglutaminase has been evaluated. Exposure to the oxidative stress increased the susceptibility of the lens proteins to transglutaminase. When ferrous ions were added to the preincubation medium, in order to convert the H2O2 into the hydroxyl radical, the increase was more evident.

Animals↗
PubMed1990

Effect of calvatic acid and its analogs on ornithine decarboxylase activity in tumour cells.

Calvatic acid (p-carboxyphenylazoxycyanide) is an antibiotic containing an azoxycyano group that displays carcinostatic activity. In the present work it has been shown that in AH-130 hepatoma and K562 leukemia cells the antibiotic, at low concentration, decreases ornithine decarboxylase (ODC) levels. The change depends on two summative effects of the drug, impairment of overall protein synthesis and inhibition of enzyme activity. Some analogs of calvatic acid have been tested in order to gain more insight into the structure-activity relationship. The decarboxylated derivative phenylazoxycyanide proved to be more effective in reducing protein synthesis and ODC activity in the whole tumor cells. The rapidly growing K562 cells displayed high sensitivity to this compound. Calvatic acid analogs devoid of the cyano group were less effective on the same parameters.

Animals↗
PubMed1989

[Arterio-venous popliteal fistula: a rare late complication of a civilian trauma. A clinical case and review of the literature].

In spite of the relatively high frequency of popliteal injuries following war and civilian traumas, a late development of an arteriovenous fistula can be considered an uncommon complication. We report a case of a chronic arterio-venous popliteal fistula in a young boy, caused five years previously by a blunt trauma, while playing. The tardive onset of symptomatology and the conspicuous enlargement of the vein underline the unusuality of the case. A review of the literature and the technique for fistula repair, using adsorbable suture, are examined.

Adolescent↗
PubMed1989

[Use of defibrotide in the treatment of acute superficial thrombophlebitis of the legs].

The efficacy of defibrotide in the treatment of acute thrombophlebitis of the legs has been investigated in 140 patients, randomized into two groups. All patients received defibrotide either alone or as an addition to conventional therapies. Two different schemes of administration were selected and carried out in each group, according to the time of onset of thrombophlebitis. Defibrotide demonstrated a good clinical efficacy in both groups, with a highly significant reduction in those patients receiving defibrotide and conventional therapies. The clinical result were outstanding in two subgroups: extensive thrombophlebitis and brachioaxillary phlebitis.

Acute Disease↗
PubMed1989

[Risk factors and etiopathogenesis of cancer of the gallbladder].

Primary cancer of the gallbladder is uncommon but not rare, being in Italy the fourth cause of death for gastrointestinal cancer in females over 65 years old. Two centuries after the first description, this tumor remains characterized by an unfavorable prognosis due to the silent progression of the clinical course and the frequent unresectability at the time of surgery. Early diagnosis, aggressive surgical approach and chemotherapy are the basis for longer post-operative survival rates; in fact, despite the advances in ultrasonography and computer-assisted imaging devices, the prevention of gallbladder cancer remains a problem. In the statistical terms, the risks of an indiscriminate surgical prophylaxis would outweigh the advantages of cancer prevention; in this optic, a recognition of the patients "at major risk" appears to be essential. With this aim we have undertaken a review of current knowledge of the "risk factors" involved in the epidemiology and etiology of gallbladder cancer, deduced from Literature and our surgical experience. It is reasonable to assume that the etiology of this cancer is based on the correlationship between factors with a wide and different penetration in racial-ethnic areas: genetic, systemic and local risk-factors. A genetic influence can be highly suspected in the familiar cases, in the non-carcinoma tumors and in the geographic predominance of the tumor. None of the systemic factors suggested as risk factors (age, sex, obesity, occupational and chemical carcinogens, drugs, etc.) appear to be directly involved; moreover, the main factors, such as female sex and age, are probably mediated through cholelithiasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystitis↗
PubMed1987

Construction of a continent perineal colostomy by using electrostimulated gracilis muscles after abdominoperineal resection: personal technique and experience with 32 cases.

A series of 32 patients operated on for rectal carcinoma is reported. A new technique by using the gracilis muscles to reconstruct a functional anal sphincter after abdominoperineal resection was performed. No operative mortality was recorded. Functionality of the new sphincter was guaranteed by electromyostimulation. Electrostimulation has been useful in both increasing the muscular trophic level and in improving the postoperative bio-feedback. Perineal infection was recorded in 9 patients being the most common complication although it did not compromise the functionality of the new sphincter. In one case acute colonic ischaemia was treated by resection and definitive left colostomy. 17 out of the 27 patients in which a functional follow-up was obtained, scored a "very good" continence to stool and flatus while in 6 patients occasional episodes of incontinence to liquid stool are referred. Local or distant metastases presented in 6 patients. The obtained results encourage in continuing the research with this technique in the attempt to reduce the number of patients that must pay the high price of a definitive abdominal colostomy for cure.

Adenocarcinoma↗
PubMed1986

Chronic clonidine treatment and its withdrawal: effects on blood pressure and catecholamine synthesizing enzymes in brain-stem nuclei.

We have studied the effects of withdrawal from chronic clonidine treatment in the adult male spontaneously hypertensive rat (SHR). SHR received clonidine, 0.1 mg X kg-1 X day-1 i.v. for 10 days. Clonidine was delivered via osmotic minipumps. After 7 days of treatment there was a 16.5 +/- 2.5 mm Hg fall in mean arterial pressure. This was accompanied by a decrease in the dopamine-beta-hydroxylase and phenylethanolamine-N-methyl transferase activities of the A1/C1 region. Withdrawal from clonidine was characterized by tachycardia and an increase in mean arterial pressure and heart rate lability. Phenylethanolamine-N-methyl transferase of the the dopamine-beta-hydroxylase activity remained diminished. The dopamine-beta-hydroxylase activity of the A2/C2 region was also diminished during withdrawal. We suggest that the blood pressure lowering effect of clonidine is accompanied by a decreased capacity to synthesize adrenaline in the A1/C1 region where adrenaline could mediate a pressor effect. Increased blood pressure lability during withdrawal is accompanied by a restoration of synthesis of adrenaline in the A1/C1 region. There is also a decrease in the capacity of synthesis of noradrenaline in the A2/C2 region where adrenaline may mediate a vasodepressor effect.

Adrenal Medulla↗
PubMed1984

Anti-ulcer drugs and hypergastrinism: utilization in surgery.

The peptic ulcer disease associated with hypergastrinemia is very often a challenging problem of diagnosis and therapy. In absolute surgical emergency (haemorrhagic and perforative complications), the utilization of the most recently discovered anti-ulcer drugs appears to be extremely helpful; the prevention of incumbent complications can be accomplished, in fact, during the post-operative treatment and the "free time" so obtained can be used for an adequate differential diagnosis (gastrinoma-induced Zollinger-Ellison syndrome: antrum retained, G cells of the antrum hyperplastic, apud-tumours with hypersecretion). The "anti-H2 and anti-muscarinic" drugs (often in association) give the surgeon the possibility of an accurate diagnosis and the choice of the best surgical procedure (tumorectomy, DCP, gastrectomy). Even in elective surgery the prevention with anti-H2 drugs permits greater "safety margins" and an optimal follow-up study. The results of the surgical experience in the General Surgical Clinic of Pisa (18 cases of Z.E.'s) confirm the validity of the associated anti-ulcer therapy.

Cimetidine↗