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R Capasso

Publications and source records attributed to R Capasso.

25 records · Page 2Linked to original sources
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

[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↗