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Biomedical subjects

R Capasso

Publications and source records attributed to R Capasso.

51 records · Page 3Linked to original sources
PubMed1996

Visceral artery aneurysms secondary to collateral circulation.

OBJECTIVE: To evaluate dilatation of visceral arteries secondary to anomalies and collateral circulation. DESIGN: Case report. SETTING: Department of Vascular Surgery, University Hospital. PATIENTS: Two patients with secondary visceral aneurysms were reported. First patient (case 1) had a mid-aortic dysplastic syndrome with multiple aneurysms of the celiac trunk and right renal artery. Other patient (- case 2) presented an inferior pancreaticoduodenal artery aneurysm associated with proximal common hepatic artery occlusion. INTERVENTIONS: The case 1 was submitted to aortic and left renal artery angioplasty (PTFEE), while in the case 2 the resection of aneurysm was performed. RESULTS: Both patients had complete resolution of symptoms and are alive today. CONCLUSIONS: Clinical observations confirmed the development of visceral artery aneurysms secondary to arterial hypertension and collateral circulation.

Adult↗
PubMed1996

Toxic metabolites from phytopathogenic Ascochyta species.

We review some chemical and biological aspects of toxic metabolites produced in vitro by phytopathogenic Ascochyta species, fungi having agrarian and toxicological importance. In particular, here the isolation of some known and new cytochalasins from A. heteromorpha and A. lathyri, four new nonenolides from A. pinodes and a new trisubstituted derivative of salycilic aldehyde from A. pisi are described. Furthermore, the identification of medicarpin, phytoalexin found in the chickpea seeds naturally infected by A. rabiei is also reported.

Carbohydrate Sequence↗
PubMed1995

Selective deficit in processing double letters.

This paper reports a patient with a selective difficulty in spelling words and pseudowords with geminate (double) consonants. In all writing tasks, deletions of a geminate consonant occurred ten times more often than deletions of a consonant in a non-geminate cluster. In addition, the probability of substituting both geminate consonants was indistinguishable from the probability of substituting one consonant in a non-geminate cluster; and, the probability of substituting only one geminate consonant was close to zero, and significantly lower than the probability of substituting one consonant in a non-geminate cluster. This pattern of performance is consistent with the hypothesis that grapheme quantity and identity are separately represented in orthographic representations. The fact that these errors occurred in the absence of a significant number of geminate transpositions is interpreted as support for the hypothesis that letter gemination is specified by a "doubling feature."

Adult↗
PubMed1995

Antibacterial polyphenols from olive oil mill waste waters.

Olive oil vegetation waters (VW) were highly toxic to both phytopathogenic Pseudomonas syringae (Smith, Yung et al.) pv. savastanoi (Gram-negative) and Corynebacterium michiganense (Gram-positive) and showed bactericidal activity in their original concentration (in raw form). Among the main polyphenols, present in the waste waters, methylcatechol proved to be the most toxic to Ps. savastanoi at 10(-4) mol l-1, and also demonstrated bactericidal activity, while on Coryne. michiganense it was only slightly active; catechol and hydroxytyrosol were less active on Ps. savastanoi, but inactive on Coryne. michiganense; tyrosol and its synthetic isomers 1,2- and 1,3-tyrosol were completely inactive on both bacteria. Among the derivatives of VW polyphenols considered, acetylcatechol and guaiacol were selectively toxic for Ps. savastanoi, while o-quinone was strongly toxic for both bacteria. The minor carboxylic polyphenols of VW at 10(-4) mol l-1 were all inactive on the bacteria. VW, catechol, 4-methylcatechol and the less abundant carboxylic polyphenols proved to be toxic on Hep2 human cells. Finally the possibility of using the active polyphenols in agriculture in an integrated pest management program for the protection of the olive plant is discussed.

Anti-Bacterial Agents↗
PubMed1994

The interaction of lexical and sublexical processes in reading, writing and repetition.

It has recently been proposed that in the course of repetition, reading aloud and writing to dictation, lexical representations are activated and selected for output by the joint operation of the semantic system and of sublexical conversion mechanisms--the Summation Hypothesis [Hillis and Caramazza, Brain Lang. 40, 106-144, 1991]. The hypothesis predicts that semantic errors in oral reading and in writing to dictation should only occur when both the semantic system and the sublexical component involved in that task (orthography to phonology and phonology to orthography conversion, respectively) are damaged. The performance of Italian patient E.C.A. indicates damage to the semantic system, and to sublexical phonology to phonology and phonology to orthography conversion mechanisms, but with substantial sparing of sublexical orthography to phonology conversion processes. In agreement with expectations derived from the Summation Hypothesis, E.C.A. produced semantic errors in repetition and in writing to dictation, but not in reading aloud. The paucity of semantic errors in speakers of languages with relatively transparent orthographies is discussed in the context of the Summation Hypothesis.

Aged↗
PubMed1992

Fast atom bombardment, electron ionization and chemical ionization mass spectrometry of 1,2,3-benzenetricarboxylic acids, inhibitors of the mitochondrial tricarboxylate carrier.

It has been discovered that 1,2,3-benzenetricarboxylic acid and some 5-substituted derivatives are specific and competitive inhibitors of the mitochondrial tricarboxylate carrier. In order to characterize these acids a study was carried out using electron ionization (EI), chemical ionization (CI) and fast atom bombardment (FAB) mass spectrometry on the free acids, the potassium salt of 1,2,3-benzenetricarboxylic acid and the corresponding methyl esters. Unimolecular decomposition processes were also studied using B/E linked scan experiments in order to correlate peaks present in the FAB mass spectra of the above compounds. The FAB ionization method, as expected, was the most suitable for analysing the very polar and thermolabile acids and the only method which could be used for the analysis of the potassium salt. EI and CI turned out to be appropriate methods for analysing the less polar and thermostable trimethyl esters.

Benzene Derivatives↗
PubMed1991

A crosslinguistic study of grammaticality judgments in Broca's aphasia.

Crosslinguistic studies of sentence comprehension and production in Broca's aphasia have yielded two complementary findings: (1) grammatical morphology appears to be more impaired than word order principles in every language studied, but (2) the degree to which grammatical morphology is retained by aphasic patients depends upon the "strength" or importance of those morphemes in the patient's premorbid language. In an earlier study comparing violations of word order and agreement, we found that English-speaking Broca's aphasics showed greater sensitivity to errors of ordering than to errors of agreement, providing further evidence for the selective vulnerability of morphology. However, because English is a rigid word order language with a relatively weak inflectional system, it could be argued that word order is resilient to brain damage because it is the strongest source of information in this language. The present study compared the performance of English-speaking Broca's aphasics and normal controls with their Italian counterparts in the same grammaticality judgment experiment. Four predictions relating to our previous work were confirmed. (1) Italian aphasics, like their English-speaking counterparts, showed general preservation of grammatical knowledge and (2) they were able to use this knowledge in an "on-line" fashion. (3) Within each language, Broca's aphasics showed greater impairment in their ability to recognize errors of morphological selection (i.e., agreement) compared with errors made by moving the same words to an incorrect position downstream. Nevertheless (4), crosslinguistic differences observed in previous studies of comprehension and production were also observed in this grammaticality judgment task: a processing advantage for agreement errors in Italian normals and aphasics, and a processing advantage for ordering errors in English normals and aphasics.

Adult↗
PubMed1989

Analysis by fast atom bombardment mass spectrometry of 4,4-dicarboxy-5-(pyridoxyl-5'-phosphate)-proline, of 4-carboxy-5-(pyridoxyl-5'-phosphate)-proline and 4,4-dicarboxy-5-pyridoxylproline.

gamma-Carboxyglutamic acid (Gla) reacts easily and quantitatively with piridoxal-5'-phosphate in H2O at room temperature, to give the 4,4-dicarboxy-5-(pyridoxyl-5'-phosphate)-proline (1). This product has been characterized by fast atom bombardment (FAB) mass spectrometry, including the B/E linked scan technique, ultraviolet and 1H nuclear magnetic resonance (NMR) analysis. In order to support further on the structure of 1, the 4-monodecarboxyderivative (2), obtained by heating compound 1 at 100 degrees C for 30 min and the 5'-dephosphoderivative (3), obtained by enzymatic hydrolysis of 1 with alkaline phosphatase, were also analysed by FAB and 1H NMR techniques. FAB was shown to be the only adequate ionization technique to deal with such thermolabile and non-volatile compounds and could provide an elegant and fast method to detect Gla in biological matrices.

Magnetic Resonance Spectroscopy↗
PubMed1979

Identification of the amino acid residues of proteins S5 and S8 adjacent to each other in the 30 S ribosomal subunit of Escherichia coli.

When Escherichia coli 30 S ribosomal subunits are reacted with protein-protein bifunctional reagents, a number of protein pairs as well as aggregates containing three or more ribosomal proteins are formed. In the present study we have purified one of the protein pairs obtained by reaction of 30 S ribosomal subunits with either radioactive or nonradioactive dimethylsuberimidate. Following molecular weight determination and ammonolysis, the pair was shown to consist of ribosomal proteins S5 and S8. The "native" structure of the complex was surmised from its capacity to be reconstituted into a biologically active 30 S ribosomal subunit. From peptide maps and primary structure determination of various peptides it was demonstrated that the cross-linking bond between ribosomal proteins S5 and S8 involves primarily the residues Lys-93 of protein S8 and the COOH-terminal lysine (Lys-166) of ribosomal protein S5. This result is substantiated by the finding that a mutant carrying an altered S5 lacking the COOH-terminal lysine yields a greatly reduced amount of S5-S8 cross-link. In addition to the points of cross-linking it was found that Lys-30, Lys-68, and Lys-86 of S8 and Lys-5 of S5 react with dimethylsuberimidate, indicating that these residues are available for reaction and suggesting their topographical localization on the ribosomal surface.

Amino Acid Sequence↗
PubMedDate not supplied

Endocannabinoids and the gut.

In the digestive tract, there is evidence for the presence of high amounts of endocannabinoids (anandamide and 2-arachidonylglycerol) and of mechanisms for endocannabinoid metabolism and possibly endocannabinoid uptake. Pharmacological studies have shown that anandamide inhibits excitatory transmission and peristalsis in the isolated guinea-pig ileum and reduces intestinal motility in the mouse in vivo; all these effects are mediated by CB(1) receptors, which are located on enteric nerves. Conversely, the selective CB(1) receptor antagonist SR141716A increased intestinal motility and this effect is likely due to the displacement of endocannabinoids rather than to its inverse agonist properties. Interestingly, inhibitory effects of anandamide via non-CB(1) receptors and stimulatory effects via vanilloid receptors have also been proposed.

Animals↗
PubMedDate not supplied

The treatment of NAFLD.

Nonalcoholic fatty liver disease (NAFLD) is becoming an increasing cause of chronic liver damage. The decision of start a medical treatment is based on the documented risk of progression to cirrhosis and liver cancer, when steatohepatitis (NASH) occurs. The therapy of this syndrome requires, as obviously, some considerations on the natural history of the condition, on the efficacy and safety of various therapeutic options, as well as on the costs. Treatment of patients with NAFLD has typically been focused on the management of associated conditions such as obesity, diabetes mellitus and hyperlipemia. Weight loss improves insulin sensitivity, and NASH may resolve with weight reduction. Insulin resistance seems to be the common denominator in many cases of NAFLD. Two classes of drugs have been shown to correct insulin resistance: biguanides (e.g., metformin) and thiazolidinediones (e.g., rosiglitazone and pioglitazone). The last two decades have witnessed a considerable progress in the understanding of the mechanisms respon-sible for the fibrogenic progression of chronic liver diseases. Several drugs believed to be hepatoprotective or antifibrotic agent as UDCA, betaine, vitamin E, lecithin, beta-carotene and selenium have been used in patients with NASH. Silybin is the main component of silymarin that is absorbed when linked whith a phytosome. This substance reduces in rats the lipid-peroxidation and the activaction of hepatic stellate cells. In humans, some non controlled data show that silybin is able to reduce insulin resistance, liver steatosis and plasma markers of liver fibrosis.

Anti-Obesity Agents↗
PubMedDate not supplied

[Hyperhomocysteinemia in chronic renal failure.].

Chronic renal failure (CRF) is frequently associated with increased plasma levels of homocysteine (Hcy), an amino acid that can be considered a new uremic toxin according to recent evidence. Studies on Hcy described first homocystinuria, an inherited disease characterized by high plasma Hcy levels and premature cardiovascular disease, resulting in high mortal-ity rates. Hyperhomocysteinemia was then shown to be associated with cardiovascular events both in the general population and in CRF patients. Hcy is a sulfur amino acid derived from dietary methionine, an essential amino acid. Methionine is condensed with ATP to form S-adenosylmethionine (AdoMet), the universal methyl donor in transmethylation reactions. The AdoMet demethylated product is S-adenosylhomocysteine (AdoHcy), which is the direct precursor of Hcy in vivo. Hcy is toxic for the endothelium, it enhances vascular smooth muscle cell proliferation, increases platelet aggregation, and acts on the coagulation cascade and fibrinolysis. Several mechanisms have been discussed to explain Hcy toxicity. Hcy levels increase as renal function declines and progresses to ESRD; the causes of hyperhomocysteinemia are still unclear. Studies in humans show that renal metabolic extraction depends on renal plasma flow; in addition, an alteration of the extrarenal metabolic clearance, depending on uremic toxins, may occur. Among the consequences of hyperhomocysteinemia in renal failure are: impaired protein methylation, with altered protein repair processes; DNA hypomethylation, with an alteration in the allelic expression of genes regulated through methylation; and protein homocysteinylation. Further, this review is dealing with the 'reverse epidemiology' issue, outlining also the main Hcy-lowering strategies.

Homocysteine↗
PubMedDate not supplied

[Hand ischemia due to "steal syndrome" in vascular access for hemodialysis].

Among complications of vascular access operations, symptomatic steal syndrome is uncommon, but may lead to ischemia of the hand. Between 1983 and 1995, 5 patients with hemodialysis fistulas presented rest pain of finger necrosis with a wrist-brachial index of 0.56 (range 0.35 to 0.63) improving to 0.96 (range 0.72 to 1.05) after digital pressure of the fistula. Ligation of distal radial artery was performed in 3 patients with side-to-end radiocephalic fistula, while basilic vein was distally ligated in a case of side-to-side brachiobasilic fistula. A vein "banding" procedure reduce fistula flow and improved distal perfusion in one patient, while a true venous aneurysm of the cephalic vein was treated by excision and replacement with a tapered PTFE graft. Hemodynamic assessment is required during surgical correction, but it may also be useful in pre- and intra-operative evaluation of patients undergoing therapeutical AVFs to prevent arterial insufficiency of the hand.

Adult↗
PubMedDate not supplied

Aortic blisters: diagnosis and evolution.

In order to evaluate the incidence, the diagnostic modalities and significance of blisters of the abdominal aortic aneurysm wall, in a retrospective review, 14 patients (2.6%) having these lesions were identified between 1983 and 1995. At preoperative examination, aortography had less accuracy (1 case = 20%) than CT scan (3 cases = 27.2%) or MRI angiography (6 cases = 85.7%) to detect blisters; others were discovered intraoperatively in the remaining four patients. Most blisters were located on the anterior or antero-lateral wall of aneurysms; its area ranged from 0.8 to 2.6 cm2. One patient with a suspected blister diagnosed at aortography, during chest physiotherapy for his COPD, presented sudden abdominal pain: at urgent laparotomy, an acute contained rupture of a large blister, without extraluminal blood loss, was found. All patients underwent aneurysm repair, with no postoperative deaths. Occurrence of rupture in one patient clearly indicates the natural course of aortic blisters. MRI angiography may accurately detect these lesions; surgical treatment is necessary for preventing imminent rupture.

Aged↗