Search PubMed⌕ Search

Biomedical subjects

A Motta

Publications and source records attributed to A Motta.

At least 73 records · Page 4Linked to original sources
PubMed1995

Influence of progesterone levels on prostaglandin concentrations in isolated uterine tissue and incubation medium from pseudopregnant rats.

We measured the synthesis and secretion of uterine prostaglandins E and F2 alpha (PGE and PGF2 alpha) by the uterus in vitro from pseudopregnant (psp) rats on days 5 and 10 of psp, when level of serum progesterone was high and low, respectively. We found a direct correlation between concentration of progesterone in serum and uterine content of PGE and an inverse correlation with uterine PGF2 alpha. On day 5, when progesterone was high in serum, PGE increased in tissue more than in the incubation medium, suggesting a poor liberation of this PG or utilization of PGE by the tissue. On this day, no difference was seen between content of uterine PGF2 alpha and PGF2 alpha in the incubation medium. Nevertheless, on day 10, when progesterone was lower, concentrations of both PGE and PGF2 alpha were greater (P < 0.001) in the medium than in the uterine tissue. However, PGF2 alpha in the medium was higher than PGE (P < 0.05). The results clearly demonstrate that the synthesis and release of PGE and PGF2 alpha were modified by the concentration of progesterone in the serum.

Animals↗
PubMed1995

Lipoprotein (a) and fibrinolytic system in liver cirrhosis. Coagulation Abnormalities in Liver Cirrhosis (CALC) Study Group.

Several observations have suggested that lipoprotein (a) (Lp(a)) is a risk factor for coronary artery disease because of potential interference with fibrinolysis secondary to its activation of plasminogen. However, there are few data on the possible role of Lp(a) in liver cirrhosis. The present study was carried out, to better elucidate its relationship to the fibrinolytic system in liver cirrhosis. We studied the plasma levels of Lp(a) and the fibrinolytic parameters of 95 patients with liver cirrhosis (57 men, 38 women, aged 26-81). Patients in Child-Pugh class C (n = 32) had significantly lower levels of Lp(a) than those in class B (n = 45), and the class B had lower Lp(a) values than class A (n = 18) (1.4 (0.0-3.7) vs 2.9 (0.0-6.1) vs 3.4 (1.8-5.5); the data are log-transformed). Alpha-2-antiplasmin and plasminogen, had patterns similar to those of Lp(a), tissue plasminogen activator (t-PA) was significantly increased only in class C (class A: 7.5 +/- 5.8 ng/ml; class B: 10.8 +/- 7.7 ng/ml; class C: 19.1 +/- 11.3 ng/ml). Patients with systemic hyperfibrinolysis (cross-linked fibrin degradation products, XDP > 200 ng/ml) also had lower levels of Lp(a) than those without 1.6 (0.0-4.4) vs (0.0-6.1); p = 0.0002. There was a significant correlation between Lp(a) and plasminogen (r = 0.43; p = 0.001). Lipoprotein (a) progressively decreases as liver cirrhosis worsens but it appears unlikely to be involved in causing the hyperfibrinolytic state often observed in advanced liver cirrhosis, in which there are marked abnormalities of several other fibrinolytic parameters, also including increased t-PA and decreased inhibitors.

Adult↗
PubMed1995

Polyurethane-coated, self-expandable biliary stent: an experimental study.

RATIONALE AND OBJECTIVES: We describe a self-expanding metallic biliary Gianturco-Rösch stent coated with polymeric material. The coating was designed to prevent the growth of neoplastic and reactive tissue within the biliary ducts. METHODS: The stents were coated with a solvent-casting technique, which consists of dissolving polyurethane (polyether urethane or polycarbonate urethane) pellets in a solvent (dimethylacetamide), dipping the stent in the solution, and completely evaporating the solvent. In vitro mechanical characterization of the stent was performed to determine the adhesion of the coating to the metallic cage, the best introducer caliber for implantation of the device, and the relationship between the stent's diameter and radial stress. RESULTS: Reports in the literature on the biostability of polycarbonate urethane compared with polyether urethane prompted us to use the former material to coat the stents. The solvent technique gives a smooth internal surface of the stent wall, leaving in relief the coated structure of the stent on the external surface. The functional tests demonstrated that the coating did not compromise the original characteristics of the stent in terms of self-expandability, axial flexibility, and increased radial rigidity of the device. CONCLUSION: Functional tests verified coating stability and device handling, which are the first steps toward in vivo experimentation.

Bile Ducts↗
PubMed1995

Biochemical and morphological changes in isolated rabbit hearts after prolonged hypothermic ischaemia: comparison of two cardioplegic solutions.

This work evaluates the myocardial protective potential of potassium cardioplegia on ischaemically arrested and reperfused hearts by two cardioplegic solutions: the University of Wisconsin solution (UW) and the standard crystalloid solution of St. Thomas' Hospital (ST). Evaluation of myocardial preservation was based on creatine kinase and lactate releases and on high-energy phosphate preservation of isolated rabbit hearts after 4 hours' hypothermic ischaemia. A morphometric ultrastructural evaluation of mitochondria in cardiomyocytes was also performed. The hearts of 24 rabbits were normothermally perfused with oxygenated Krebs-Henseleit solution for 30 min (Langendroff preparation), and the baseline contractile performance and biochemical parameters were evaluated. The hearts were then arrested and stored in the cardioplegic solutions (12 UW and 12 ST) at 4 degrees C for 4 hours. The hearts were then rewarmed and reperfused with oxygenated Krebs-Henseleit solution for further 30 min. At the end of reperfusion, creatine phosphate and high energy phosphates were higher with UW (p < 0.05); creatine kinase release during reperfusion was significantly lower with UW both at 15 min (p < 0.01) and at 30 min (p < 0.05). Lactate release during the first 15 min of reperfusion was about doubled (p < 0.05) with respect to controls in both groups; at 30 min this increase had almost vanished (+8%) with UW but not with ST (+30%). Ultrastructural morphometry did not show any significant difference at the level of mitochondria between the two treatments. The results indicate, for UW, an improved myocardial preservation associated with relative retention of high-energy phosphates and higher recovery of mechanical function, accelerated metabolic recovery and reduced stress of cell membranes.

Adenosine↗
PubMed1994

Prevalence and pattern of major neurological disorders in rural Kashmir (India) in 1986.

In 1986 in the Kuthar Valley in the Anantnag District of south Kashmir (northwestern India), we studied the population to ascertain the prevalence and pattern of various neurological diseases. A house-to-house survey was done in a rural population of 63,645 (according to a World Health Organization protocol, 1981). 616 cases of major neurological disorders were detected, yielding a prevalence of ratio of 9.67/1,000 as of prevalence day November 1, 1986. The prevalence ratios for various common neurological disorders were: epilepsy 2.47/1,000; stroke 1.43/1,000; paralytic poliomyelitis 2.18/1,000; mental retardation 2.09/1,000; deaf mutism 1.63/1,000, and cerebral palsy 1.24/1,000. Persons with these conditions constituted 92% of all neurological cases. Patients with motor neuron disease, Alzheimer's dementia or multiple sclerosis were not found.

Adolescent↗
PubMed1994

Plasma levels of tumor necrosis factor and endothelial response in patients with chronic arterial obstructive disease or Raynaud's phenomenon.

Tumor necrosis factor alpha (TNF-alpha) is a cytokine that affects endothelial cells' function by changing their antithrombotic potential to a net procoagulant effect. Only a few data have so far been reported for the pathophysiologic role of TNF in vascular diseases in the involvement of microvessels and/or macrovessels and a prothrombotic state. In the present study the authors evaluated plasma TNF (and interleukin-1) levels in 20 patients with chronic arterial obstructive disease (CAOD) with intermittent claudication and 10 CAOD patients with more severe disease (pain at rest/skin ulcers). In addition, they studied 10 patients with Raynaud's phenomenon (RP), suspected to be secondary to a collagen disease. The control group consisted of 20 subjects matched for sex and age with the three groups of patients. TNF levels were assayed by enzyme-linked immunosorbent assay. The antigen levels of von Willebrand factor (vWF), tissue plasminogen activator (t-PA), and its inhibitor (PAI) were also determined as markers of release from the endothelium, while the fragment 1 + 2 of prothrombin (F1 + 2) and thrombin-antithrombin III (TAT) complexes were assessed as indexes of systemic thrombin generation. TNF levels were significantly higher in both groups of CAOD patients than in controls or RP patients, and the same was true for vWF. t-PA was significantly higher only in the CAOD subjects with more severe disease. No differences among groups were seen in PAI antigen/activity or thrombin generation. When data were corrected for age, TNF no longer differentiated CAOD patients from controls and RP subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Preservation of rabbit hearts with different cardioplegic solutions at low temperature.

An organ-preserving solution, including in its composition also organic molecules, prepared at the University of Wisconsin (UW), has been successfully used for preservation of liver, pancreas and kidney, and has recently been tested for long-term storage of isolated hearts. We have compared the effectiveness of the UW solution with that of a standard crystalloid cardioplegic solution (St. Thomas, ST) in the functional and structural preservation of isolated hearts. The hearts taken from 24 rabbits were mounted on a Langendorff preparation. After assessment of the left ventricular function by an intraventricular balloon, 40 ml of either cardioplegic solution were injected to arrest the hearts (12 UW and 12 ST), which were then immersed in the same solution for 4 h at 4 degrees C without perfusion. After this period, the hearts were normothermally reperfused with oxygenated Krebs-Henseleit solution for 30 min, and finally left ventricular function was assessed again. An electron microscopic evaluation was performed as well. Significantly higher recovery of left ventricular developed pressure (p < 0.01) and of negative dP/dt (p < 0.05), was observed after preservation with UW, while no difference on positive dP/dt was found. After reperfusion, left ventricular end-diastolic pressure significantly rose with ST (p < 0.01), but did not change with UW; the difference between ST and UW was significant (p < 0.01). Tissue water content was significantly lower in the hearts preserved with UW (p < 0.05). Electron microscopic examination revealed generally good preservation with no substantial difference between the two solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

[Clinical considerations in Raynaud's phenomenon. How many and which patients are treated?].

Among the multiple aspects about which little is still known about Raynaud's phenomenon (RP), is that, in the author's opinion, regarding the question: how many and which patients are sufficiently troubled by this pathology to seek medical treatment from their own GP or specialist, and what are the results of any treatment commenced. The following questions were put to a group of 180 patients affected by RP attending the out-patient clinic for the first time: 1) how many had already received treatment; 2) which patients were receiving pharmacological treatment and/or had undergone surgery. In this context, the authors assessed the influence of the following parameters on the fact that they had or had not been treated: a) the age of patients; b) the duration of disease; c) the presence of stenosing or obliterating arterial lesions (RP on an organic basis); d) the co-presence of pathologies considered to be the possible etiological cause of RP in literature; e) the severity of symptoms; 3) what results were obtained by medical and/or surgical treatment; 4) what was the course of RP which failed to respond to therapeutic measures. The study examined a series of 180 subjects including 139 (77.22%) females (mean age 47.6% years) and 41 (22.78) males (mean age 42.4 years). Symptoms had been present for a period ranging between 2 and 44 years (mean 10.01). In order to ascertain the possible presence of associated diseases considered by many authors to be causal factors, all patients underwent hemotochemical and instrumental test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Singular case of tardive anastomotic disjunction in a Dacron R vascular graft.

We investigated a case of anastomotic disjunction of the termino-lateral insertion of a bifurcate aortic graft in the right external iliac artery. The graft in woven Dacron R n. 19, was implanted in 1977 and the left femoral insertion became infected shortly after surgery. The infection was treated according to standard procedures with removal of the infected branch, reconstruction with the transobturatory by-pass and antibiotics. For antibiotic treatment of local and general sepsis the approach was completely new as regards dose regimen and duration. In 1993 a pseudoaneurysm developed through weakening of the right iliac anastomosis. In view of the anamnesis we were surprised to find that the origin was of a mechanical nature.

Aged↗
PubMed1993

Probing protein structure by solvent perturbation of NMR spectra. II. Determination of surface and buried residues in homologous proteins.

The experimental assignment of most residues in a protein to the surface or interior is in principle possible without prior solution of a complete three-dimensional structure. The method described is based on nmr measurements that determine the amino acid composition of the surface of a protein [A. Petros, L. Mueller, and K.D. Kopple (1990) Biochemistry, Vol. 29, pp. 10041-10048; G. Esposito, A. M. Lesk, H. Molinari, A. Motta, N. Niccolai, and A. Pastore (1992) Journal of Molecular Biology, Vol. 224, pp. 659-670]. If these measurements are carried out on several homologous proteins of known sequence, it is possible to combine the results to determine, in most cases, which positions in the sequence contain exposed residues.

Amino Acid Sequence↗
PubMed1993

Frontal lobe dysfunction in multiple sclerosis as assessed by means of Lurian tasks: effect of age at onset.

We investigated frontal cognitive function in a group of 153 patients with multiple sclerosis and 100 healthy controls using a global scale composed by a set of items from the Luria-Nebraska Neuropsychological Battery (LNNB) which has been validated by Malloy and colleagues on frontally damaged patients. A second scale was built with LNNB items tapping parietal lobes function. Patients who were specifically impaired on the frontal scale (12%) had a shorter disease duration and were less physically disabled than those failing on the parietal tasks (8.5%) or those showing combined deficits (21.5%). Sixty-four patients were also tested on the Wisconsin Card Sorting Test (WCST). Twenty-seven (37.5%) patients were found to be impaired on the WCST, but the latter could not predict reliably their performance on the LNNB frontal scale. We also examined whether age of onset and disease duration could have had any effect on the cognitive performance of selected groups of patients. We found that relative to normals, deficits on the frontal scale were more severe in patients with a clinical onset around age 20 than in patients with a later onset (i.e., around 35), the two groups being comparable for duration and degree of disability. Furthermore, patients with a longstanding illness (> 10 years) were more affected on visuospatial processing and frontal control of language than those with a short duration (1.5 yrs). We propose that a greater disease activity interacting with contingent (developmental?) factors is responsible for the appearance of transient frontal deficits in several young MS patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

MRI and cognitive patterns in relapsing-remitting multiple sclerosis.

We studied the relationships between magnetic resonance imaging (MRI) and the Luria-Nebraska Neuropsychological Battery (LNNB) in 64 patients with relapsing-remitting multiple sclerosis (MS). MRI films were scored according to arbitrary descriptive criteria designed to emphasize patterns of alterations. Five groups were created: group 1 and 2 had typical discrete white matter lesions, group 3 had confluent lesions, group 4 had large discrete lesions and group 5 had only few small lesions. In addition, groups 2 and 3 had evidence of parenchymal atrophy. Groups 2 and 3 were the most impaired on the LNNB, but none of these patients was actually demented. Groups 1 and 5 were globally intact in spite of very different mean age and MRI pattern. Group 4 was composed of younger subjects with a shorter disease duration; they showed mild loss of attentive and abstracting abilities. We suggest that since their MRI was showing greater signs of local biological activity their mental deficits may be a transitory condition capable of two distinct outcomes: a favorable one as in groups 1 and 5, and a slowly progressive one associated with loss of brain tissue as in groups 2 and 3.

Adolescent↗
PubMed1993

The hyperfibrinolytic state of liver cirrhosis: possible pathogenetic role of ascites.

We evaluated coagulation and fibrinolytic parameters in both plasma and ascitic fluid of 39 patients with ascites secondary to liver cirrhosis and in 14 cirrhotic patients without ascites, in order to verify if the peritoneal compartment could be involved in the pathogenesis of the hyperfibrinolytic state of the disease. An activation of fibrinolysis, as suggested by increased levels of FDP, D-dimer and tissue plasminogen activator (t-PA) was demonstrated in both ascitic fluid and to a lesser extent in plasma. A positive correlation was also observed between plasma and ascitic fluid plasminogen, anti-plasmin and fibrinogen, while a negative correlation was found between plasma and ascitic fluid plasminogen activator inhibitor-1 (PAI-1). Moreover, plasma PAI-1 was significantly lower in patients with ascites than in those without ascites and among ascitic patients in those who had bleeding into soft tissues when compared to those who did not present haemorrhagic events. Finally, a significant association was also shown between positivity for plasma D-dimer (> 200 ng/ml) and the presence of ascites. Taken together, our data suggest an exchange of some coagulation and fibrinolytic proteins between plasma and ascitic fluid and point out the key role of PAI-1 in regulating plasma fibrinolytic potential and in bleeding complications in cirrhotic patients.

Adult↗
PubMed1993

Relationship between factors influencing Na(+)-K(+)-ATPase activity and eicosanoid production from 14C-arachidonic acid in spayed rat uterus.

Na(+)-K(+)-ATPase activity has been implicated in the metabolism of arachidonate and the release of prostaglandins (PG). The aim of the present study was to investigate a potential interaction between the activity of this enzyme and the production of bisenoic PG by uteri isolated from spayed rats. Ouabain or the incubation in low K+ medium (conditions which inhibit Na(+)-K(+)-ATPase) diminished the conversion of 14C-arachidonic acid to 6-keto-PGF1 alpha and PGF2 alpha and increased the production of TXB2. The incubation of uterine strips in a high K+ medium (condition which enhances Na(+)-K(+)-ATPase activity) increased the formation and release of 6-keto-PGF1 alpha and PGF2 alpha while the production of TXB2 and PGF2 diminished significantly. These observations suggested that the activity of Na(+)-K(+)-ATPase could modulate the production of PG and that could be involved in the alterations of the metabolism of eicosanoids found in several tissues during diabetes.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Anastomotic disjunction in long-term patent vascular synthetic grafts in Dacron.

This study follows the recently published paper on the in vivo behaviour of patent Dacron vascular prostheses and focuses in particular on anastomotic disjunction. The question of the evolution of anastomoses was tackled by examining its three basic components: prosthetic tissue, suture thread and arterial wall. The authors' observations were based on material taken from reoperations performed between 7 and 18 years after the first graft. These data enable the authors to affirm that the prosthesis undergoes a general physical and chemical deterioration which varies in intensity according to the type of weaving. On the contrary, in the anastomotic zone this phenomenon is not intense enough to jeopardize the anchorage of the suture thread since the original weft does not show any loss of compactness. In spite of surface morphological deterioration of various intensity, the suture threads maintain satisfactory mechanical properties and structural integrity. The artery wall in the anastomotic zone shows a massive degeneration in terms of its true anatomic structure responsible for the rupture of the suture rima. On the basis of these results the authors conclude that this phenomenon represents the "Achilles' heel" of anastomotic junction.

Aged↗
PubMed1993

[Biodegradation of dacron vascular prostheses. Physico-chemical, histological, morphometric and ultrastructural study].

The paper deals with study of long-term stability as far as concerns Dacron vascular prostheses in woven and knitted double velour. Among our vascular prostheses case-reports, we evaluated three of them explanted after 11, 12, 20 years; all of the prostheses were patent. Chemical-physical, histopathological and ultrastructural analysis have been carried on in order to evaluate in vivo ageing of the examined prostheses. The results all indicate strong alterations of the original properties related to double velour of knitted prostheses and weak alterations of woven one.

Aged↗
PubMed1992

Probing protein structure by solvent perturbation of nuclear magnetic resonance spectra. Nuclear magnetic resonance spectral editing and topological mapping in proteins by paramagnetic relaxation filtering.

Soluble spin labels, which "bleach" the surface proton resonances of a protein to n.m.r. measurements, can provide useful information about protein conformation and dynamics. The use of the soluble nitroxide, TEMPOL, has been explored to show the correlation of the paramagnetic perturbations of protein two-dimensional n.m.r. data with proton exposure to the free radical in hen egg-white lysozyme. The results demonstrate that the nitroxide approaches the protein randomly, and that the extent of the observed paramagnetic effects reflects the native folding pattern of the protein. A correlation of spectral simplification with the known tertiary structure establishes the feasibility of new strategies for topological mapping of surface and buried protons of the protein. Application to the elucidation of protein structure and to the study of dynamical processes is discussed.

Amino Acid Sequence↗