PubMed Health⌕ Search

Biomedical subjects

A M Ferrari

Publications and source records attributed to A M Ferrari.

At least 19 recordsLinked to original sources
PubMed2005

Experimental and theoretical study of a surface stabilized monolayer phase of nickel oxide on Pd(100).

A surface stabilized monolayer phase of nickel oxide, c(4 x 2)-Ni(3)O(4), has been found to grow epitaxially under reactive deposition conditions on Pd(100), in the presence of other adsorbed phases and in competition with them. High-quality scanning tunneling microscopy data are reported and discussed, including a detailed analysis of the defects and of the border morphology of this new phase. The data are discussed in the light of ab initio simulations of the electronic, energetic, and geometric properties of such a phase. A hybrid-exchange density functional theory approach has been used, and a slab model is adopted where palladium is simulated by a thin film covered on both sides by regular epilayers. A growth model has been developed that explains both the unusual stoichiometry of the phase and the observed defects.

Journal Article↗
PubMed2002

Electropherotypes of rotaviral RNA from cases of infantile diarrhea in Uruguay.

Electropherotypes of human rotavirus isolates from infants with acute diarrhea belonging to two populations with different clinical features were determined. Thirteen electropherotypes were identified in total 69 isolates; 46 (66.6%) isolates had long RNA migration patterns and 23 (33.3%) isolates had short migration pattern. One of the long-pattern electropherotypes (47.82% of the total electropherotypes) was predominant. It was detected in both populations almost throughout the whole period of the study, while other electropherotypes were found only occasionally. The co-circulation of long and short electropherotypes was not frequent.

Diarrhea, Infantile↗
PubMed2001

Identification of defect sites on MgO(100) thin films by decoration with Pd atoms and studying CO adsorption properties.

CO adsorption on Pd atoms deposited on MgO(100) thin films has been studied by means of thermal desorption (TDS) and Fourier transform infrared (FTIR) spectroscopies. CO desorbs from the adsorbed Pd atoms at a temperature of about 250 K, which corresponds to a binding energy, E(b), of about 0.7 +/- 0.1 eV. FTIR spectra suggest that at saturation two different sites for CO adsorption exist on a single Pd atom. The vibrational frequency of the most stable, singly adsorbed CO molecule is 2055 cm(-)(1). Density functional cluster model calculations have been used to model possible defect sites at the MgO surface where the Pd atoms are likely to be adsorbed. CO/Pd complexes located at regular or low-coordinated O anions of the surface exhibit considerably stronger binding energies, E(b) = 2-2.5 eV, and larger vibrational shifts than were observed in the experiment. CO/Pd complexes located at oxygen vacancies (F or F(+) centers) are characterized by much smaller binding energies, E(b) = 0.5 +/- 0.2 or 0.7 +/- 0.2 eV, which are in agreement with the experimental value. CO/Pd complexes located at the paramagnetic F(+) centers show vibrational frequencies in closest agreement with the experimental data. These comparisons therefore suggest that the Pd atoms are mainly adsorbed at oxygen vacancies.

Journal Article↗
PubMed2001

An additional structural and electrical study of polymeric haloplumbates(II) with heterocyclic diprotonated amines.

The crystal structures of three polymeric bidimensional piperazinium, N,N'-dimethylpiperazinium, and N-benzylpiperazinium hydrate haloplumbates(II) and one polymeric monodimensional N,N'-dimethylpiperazinium hydrate haloplumbate(II) were determined by means of X-ray analysis. The (pipzH2)[PbCl4] salt is monoclinic, space group P2(1)/c, with a = 5.778(2) A, b = 22.612(26) A, c = 9.061(4) A, beta = 95.37(6) degrees, Z = 4; (me2pipzH2)[PbBr4] crystallizes in the monoclinic P2(1) space group with a = 6.101(3) A, b = 18.822(12) A, c = 6.229(2) A, beta = 98.62(4) degrees, Z = 2; the crystals of (me2pipzH2)2[Pb3I10].4H2O are monoclinic, space group P2(1)/c, a = 19.054(4) A, b = 12.239(3) A, c = 18.273(4) A, beta = 93.42(12) degrees, Z = 4; (benzpipzH2)3[Pb2Br10].2H2O crystallizes in the monoclinic P2(1)/c space group with a = 22.380(22) A, b = 9.304(15) A, c = 24.577(25) A, beta = 94.28(11) degrees, Z = 2. Different model type structures, such as one-dimensional linear chain, ribbonlike, and perovskite-like, were observed, and factors governing these structural arrangements are pointed out. The compounds were also investigated by means of thermal and electrical measurements, and correlations between electrical properties and crystal structures were noted.

Journal Article↗
PubMed2001

Synthesis and cytotoxicity of bis(benzo[g]indole-3-carboxamides) and related compounds.

A series of bis(benzo[g]indoles) bridged by CX-(CH2)nN(Me)(CH2)n-CX (X = O, S, H2; n = 2,3) was synthesized as bifunctional antitumor agents and evaluated for cytotoxic activity against diverse human cancer cell lines by the National Cancer Institute. The parent compounds 2a,b exhibited a good level of activity and derivates 2c-g,i,k demonstrated significant inhibitory effects, all with IC50 values in the low micromolar range. The thioamide analogue 2j showed less potency. It is interesting to note that introduction of substituents on the benzene ring of the benzo[g]indole portion of 2a,b did not affect activity, with the only exception of the 7,8-dichloro derivative 2h which became less potent. One member of this series, 2i, was then tested in the hollow fiber cell assay to evaluate, in a preliminary fashion, its in vivo antineoplastic activity. Molecular modelling studies were performed on amide 2a and thioamide 2j to explain the loss of activity of 2j as to 2a. Finally, compound 2a behaved as a typical DNA intercalating agent, as judged from viscosity measurements with Poly(dA-dT)...poly(dA-dT).

Amides↗
PubMed2001

Standard case management of pneumonia in hospitalized children in Uruguay, 1997 to 1998.

OBJECTIVE: To report the results of the use of antimicrobial guidelines for the management of children with community-acquired bacterial pneumonia. METHODS: Admittance and discharge criteria and algorithms for diagnosis and treatment were established. The decision to treat with antibiotics was based on radiologic findings in pneumonia with pulmonary consolidation and left to the attending physician's criteria in the remaining cases. The use of antibiotics was limited to penicillin and derivatives (ampicillin, amoxicillin) and macrolides. RESULTS: Of the 1163 children treated as bacterial pneumonia, hospitalized in public and private health facilities in Montevideo from September, 1997, through September, 1998, standard case management was applied in 1082 (93%). Age distribution was: <1 month, 1%; between 1 and 11 months, 29%; between 1 and 5 years, 50%; >5 years, 20%. Chest radiography showed evidence of pulmonary consolidation in 843 children (73%). Bacteria were detected in blood culture and/or pleural fluid of 57 children (5%). In 51 the identified microorganism was Streptococcus pneumoniae, susceptible to penicillin in 30, intermediate in 6 and resistant in 5 (maximum MIC, 4 microg/ml); in 10 cases etiologic diagnosis was made by antigen detection. Empyema was present in 62 children (5.3%); 38 (3.27%) required treatment in an intensive care unit; and 5 (0.4%) died. CONCLUSIONS: Compliance with standard case management was highly satisfactory. Outcome of children treated with penicillin and derivatives was good, including children with empyema and pneumatocele and two patients with penicillin-resistant S. pneumoniae. At the present time S. pneumoniae resistant to penicillin is not an important problem in children with pneumonia in Uruguay. Surveillance of identified microorganisms and their antimicrobial susceptibility must continue.

Algorithms↗
PubMed2001

Etiology of children's diarrhea in Montevideo, Uruguay: associated pathogens and unusual isolates.

We studied microorganisms associated with infant diarrhea in a group of 256 children admitted to a public pediatric hospital in Montevideo, Uruguay. Diagnostic procedures were updated to optimize detection of potential pathogens, which were found in 63.8% of cases, and to be able to define their characteristics down to molecular or antigenic type. Coinfection with two or more agents was detected in more than one-third of positive studies. Escherichia coli enteric virotypes, especially enteropathogenic E. coli (EPEC), were shown to be prevalent. Rotavirus, Cryptosporidium, Campylobacter (mainly Campylobacter jejuni), and Shigella flexneri were also often identified. Enterotoxigenic E. coli, Salmonella, and Giardia lamblia were sporadically recognized. Unusual findings included two enteroinvasive E. coli strains, one Shigella dysenteriae 2 isolate, and a non-O:1 Vibrio cholerae culture. EPEC bacteria and S. flexneri (but not Salmonella) showed unusually frequent antimicrobial resistance, especially towards beta-lactam antibiotics, which is the subject of ongoing work.

Animals↗
PubMed2000

Preparation of thieno[3,2-h]cinnolinones as matrix metalloproteinase inhibitors.

A new series of thieno[3,2-h]cinnolinone analogues was synthesized which is structurally related to 2,3,4,4a,5,6-hexahydrothieno [3,2-h]cinnolin-3-one 1, a weak inhibitor of the matrix metalloproteinase MMP-8 (human neutrophil collagenase). Preliminary SAR studies have shown that while C4a-methyl, C7-acetylamino, C7 and C8-nitro substitution, and C4-C4a olefination provided no increase in activity relative to 1, C8-acetylamino substitution as in 5 and 8 was favourable. Moreover, to predict how the thieno[3,2-h]cinnolinone inhibitors might bind to MMP-8, the unsubstituted compound 9 was docked into the MMP-8 crystal structure. These studies revealed that inhibitor 9 does not seem to be able to coordinate the catalytically-active zinc ion but preferably interact with the peptide-binding region of the active site.

Binding Sites↗
PubMed1996

Chronic dexamethasone treatment and its effects on sensory neuropeptides, pulpal injury reactions and reparative dentin.

Initial sensory nerve reactions to dental injuries include terminal sprouting and intensified immunoreactivity for calcitonin gene-related peptide (CGRP) and substance P (SP); those reactions are reduced at 4 days after injury when rats are treated daily with dexamethasone (DEX) [17]. Here we have analyzed long-term effects of DEX (daily, 0.2 mg/kg) on wound healing, sensory nerve sprouting, and CGRP/SP intensity at 7-14 days after cavity preparation. All DEX treated rats had loss of appetite and stopped growing during the postoperative periods while controls had normal postoperative growth. After 7-14 days, CGRP immunoreactivity (IR) was decreased to one-third of normal (P < 0.05) compared to vehicle in both the intact and injured molar pulp, and SP also decreased, but the neuropeptide intensity in adjacent periodontal innervation was not changed. Pulpal injury and inflammation were reduced by DEX treatment, but reparative dentin was formed just as well in the DEX rats as in the vehicle group. When the injured teeth formed fibrous dentin, there was sprouting of nerves towards that matrix, and DEX did not inhibit that reaction. The sprouts could contain intense neuropeptide immunoreactivity in DEX rats even though the CGRP/SP intensity in uninjured pulp was reduced. We conclude that (1) chronic DEX treatment causes a generalized decrease in CGRP and SP neuropeptides in pulpal nerves but not in periodontal ligament; (2) it reduces abscess formation in injured teeth; (3) it does not block reparative dentin formation; and (4) it does not block sprouting of pulpal nerves towards fibrous dentin. The selective loss of pulpal neuropeptides CGRP and SP during dexamethasone treatment may be caused by reduced dental function since there was substantial loss of appetite and chronic weight loss during the 1-2 week treatment periods.

Animals↗
PubMed1994

Combined endoscopic and surgical management of Dieulafoy vascular malformation.

BACKGROUND: Dieulafoy's disease (exulceratio simplex) is an uncommon cause of gastric hemorrhage as a result of an abnormally large, submucosal, eroded gastric artery, often located in the upper part of the stomach. It represents a clinical challenge because of the intermittent nature of massive bleeding accounting for a constantly fatal course in conservatively (nonsurgically or nonendoscopically) treated patients. Published therapeutic options include techniques of endoscopic hemostasis or operative procedures. STUDY DESIGN: Herein we report two patients in whom a combined endoscopic and operative approach was performed to obtain a definitive prevention of rebleeding and an undoubted anatomopathologic diagnosis. RESULTS: Our innovative combined endoscopic and operative approach has offered three significant advantages: endoscopic preoperative diagnosis and control of the bleeding; valid aid in the intraoperative localization of hemorrhagic lesions, which is erratic intraoperatively, requires gastrotomy, and prolongs the duration of operation; and endoscopy-guided limited wedge resection as opposed to standard techniques involving gastrotomy for simple ligation or oversewing of the involved vessel, local excision, or wide wedge resections that used to be recommended until the recent past. CONCLUSIONS: We confirm that seemingly obscure origins of massive recurring hemorrhage of the upper part of the gastrointestinal tract should increase the suspicion of Dieulafoy's disease, prompting careful examination of the gastric fundic area and greater curvature. Endoscopic hemostasis is the first choice; whenever operative treatment is indicated (because of the endoscopic or clinical situation), it should be as conservative as possible because of intraoperative endoscopic localization of the bleeding source.

Aged↗
PubMed1993

Are routine duodenal and antral biopsies useful in the management of "functional" dyspepsia? A diagnostic and therapeutic study.

Fifty-three patients with previously uninvestigated chronic dyspepsia symptoms in the absence of gastrointestinal or extra-gastrointestinal disease (functional dyspepsia) underwent antral and duodenal mucosal biopsies to detect the role of such samplings in the presence of normal endoscopic findings. Patients were enrolled in a randomized, placebo-controlled, double-blind trial, receiving either eradicating treatment (colloidal bismuth subcitrate plus metronidazole) or placebo if they had Helicobacter pylori-associated gastritis (20 patients), or cisapride or placebo if they had normal antral mucosa (28 cases). Unsuspected celiac sprue was found in one patient. Eradicating treatment ameliorated histological gastritis (p = 0.01). However, owing to great placebo efficacy, symptom remission rates following a 1-month wash-out period in both treatment groups were no higher than that in controls. Independent of the initial randomization, an extremely low symptom recurrence rate was observed during a drug-free follow-up study equivalent to the mean duration of symptoms before enrollment. We conclude that in functional dyspepsia, bulbar and antral biopsies are not useful in clinical management, equivalent symptom relief can be achieved in patients randomly assigned to both drugs and placebos, and such improvement can be long lasting in the absence of any maintenance treatment. We believe the prevalence of unsuspected villous atrophy and the therapeutic role of investigation-based reassurance deserve further assessment.

Adult↗
PubMed1991

IIB osteosarcoma. Current management, local control, and survival statistics--the Australian experience.

Current management of osteosarcoma at the authors' institution involves intraarterial induction chemotherapy using intermittent cycles of cisplatin and doxorubicin (Adriamycin), surgical resection with limb-sparing wherever possible, and adjuvant systemic chemotherapy (high-dose methotrexate with retrieval and doxorubicin). Twenty cases treated in this way between May 1983 and May 1989 are reviewed. There were 18 Stage IIB osteosarcomas and two Stage IIB malignant fibrous histiocytomas. Chemotherapeutic effect was evaluated in the resected tumors. There was little correlation between the clinical response to the induction chemotherapy and cell necrosis present in the resected tumor mass. Wide resection margins were achieved in 17 cases, a minimal margin in two, and a contaminated margin in one. Radiotherapy was used in these three cases where resection margin was in doubt. There were two local recurrences in these three cases. Four patients have died of their disease, and there was one treatment-related death. Overall probability of survival in this group of 20 patients has been expressed by the Kaplan-Meier method as 58%.

Adolescent↗
PubMed1991

Hemoductal pancreatitis secondary to gastroduodenal artery-ruptured pseudoaneurysm: a rare cause of hematemesis.

A 65-yr-old alcoholic man with a history of calcific pancreatitis presented with massive hematemesis complicated by lipothymia. Physical examination disclosed stigmata of chronic liver disease. The laboratory picture was predominantly of cholestatic type with impaired liver protein synthetic activity. Emergency esophagogastroduodenoscopy was unable to provide definitive diagnosis, but reendoscopy with a side-viewing duodenoscope revealed active bleeding through the ampulla of Vater. An ultrasound examination showed a large, complex pancreatic lesion that computed tomography showed to be a pancreatic pseudocyst with an inside pseudoaneurysm. A visceral angiography revealed an anomalous arising of the common hepatic artery from the superior mesenteric artery and a pseudoaneurysm of the gastroduodenal artery at its origin. A second massive hemorrhage required an emergency operation, and surgical liver biopsy revealed focal steatosis. In conclusion, bleeding of a pancreatic pseudoaneurysm may be massive but intermittent, and side-viewing duodenoscopy, even prolonged, is essential in the diagnosis.

Aged↗
PubMed1990

[Acute intrathoracic respiratory infections in hospitalized children. Uruguay 1984-1986].

Between may 1984 and november 1986, a study, which included 475 children under five years of age hospitalized due to acute intrathoracic respiratory infections, was carried out in order to obtain clinical, radiological and etiological characteristics which may aid in establishing norms to diagnose and treat these patients. Nasopharyngeal aspirations were performed on each child, while viral diagnosis was done through viral isolation techniques and indirect immunofluorescence. The presence of a virus was detected in 34.4% of the cases and in 28.8% of a subsample. A precoded questionnaire was used to obtain the clinical information needed and all X-rays were reviewed by the same radiologist using simple pre-established criteria. A comparison was made on the similarities found between both the clinical and radiological diagnosis, as well as the sensitivity and specificity of some of the clinical signs which characterize bronchiolitis and the pneumoniae.

Acute Disease↗
PubMed1987

Serum CA 19-9 in the postsurgical follow-up of patients with pancreatic cancer.

In the last few years serum CA 19-9 has been shown to be a highly sensitive marker of pancreatic adenocarcinoma. This study assesses the value of serum CA 19-9 assay in the postsurgical follow-up of patients undergoing pancreatic cancer resection. In 14 patients with cancer in the head of the pancreas and abnormal preoperative serum CA 19-9 values (greater than 40 U/ml), a pancreatoduodenectomy was performed. In all patients the CA 19-9 antigen was immunohistochemically demonstrated on the removed tumoral tissue. Postoperative serum CA 19-9 concentrations were serially measured 15 days after surgery and then every other month. Serum CA 19-9 scores returned to the normal range only in 7 (50%) of the resected patients. All patients with a normal postoperative value and none of those with a persistently elevated one survived longer than 7 months. Early postoperative serum CA 19-9 assay was superior to perioperative staging of the tumor as a prognostic index. All of the seven patients with postoperative normal values exhibited a subsequent increase within 16 months. In all cases the elevation of CA 19-9 occurred at least 2 months before ultrasound (US) could detect local recurrences of hepatic metastasis. Our data indicate that a normal early postoperative CA 19-9 score is a relatively favourable prognostic index in patients who undergo radical surgery for pancreatic cancer and that the CA 19-9 test can be used, as an early marker of recurrence, in monitoring these patients.

Adenocarcinoma↗
PubMed1986

Immunohistochemical study of the appearance of some markers in liver adjoining hepatocellular carcinoma.

The presence and distribution of AFP, AAT and HBsAg in peritumoral non-neoplastic hepatocytes (NNH) of 27 cases and, at the same time, in the neoplastic tissue of 37 liver cell carcinoma (HCC) were studied; AFP and HBsAg were more frequently found in NNH than in HCC cells; no differences were found for AAT. The presence of HBsAg also in normal liver without cirrhosis is probably best explained by its possible role in neoplastic transformation and by the inhibition of replication of the viruses AFP, considered to be expression of dedifferentiated cells, may possible be taken up by NNH for catabolic purposes.

Aged↗