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Biomedical subjects

G Palma

Publications and source records attributed to G Palma.

At least 37 records · Page 2Linked to original sources
PubMed1991

Biocompatible polyphosphazenes by radiation-induced graft copolymerization and heparinization.

Investigations were carried out on the radiation-induced graft copolymerization by direct irradiation of dimethylaminoethyl methacrylate on to poly(bis(trifluoroethoxy)phosphazene) and on to poly (bis(phenoxy)phosphazene). Kinetics of grafting were followed with the polyphosphazenes immersed in monomer - methanol mixtures of various composition. The grafted film samples were quaternized with methyl iodide and, to the produced ammonium group, heparin was ionically bonded with high yield. On the grafted and heparinized-grafted film samples an evaluation of hydrophilicity, mechanical properties, biocompatibility and anticoagulating properties was carried out.

Animals↗
PubMed1991

Correlation between histopathology, immune response, clinical presentation, and evolution in Leishmania braziliensis infection.

Skin biopsies from 221 parasitologically confirmed cases of tegumentary leishmaniasis caused by Leishmania braziliensis spp. were evaluated with respect to histopathology, the qualitative and quantitative nature of the cellular infiltrate, and the presence of Leishmania amastigotes. These variables were cross correlated with the Leishmania-specific immune response, clinical presentation, and response to treatment. Physical evidence of prior leishmanial lesions was associated with the absence of amastigotes (P less than or equal to 0.001) and the presence of giant (P = 0.03) and epitheloid cells (P = 0.03) in the biopsy of the active lesion. The presence of amastigotes was inversely related to the duration of the lesion (P less than or equal to 0.001) and the presence of eosinophils (P less than or equal to 0.01), whereas the presence of adenopathy (P = 0.01), necrosis (P = 0.001), histiocytes (P = 0.001), and increased serum antibody titer (P = 0.02) were directly associated with the presence of amastigotes. The lymphocyte transformation response was correlated with the presence of granulomas (P = 0.001), but showed no correlation with cutaneous delayed type hypersensitivity. The presence of epithelioid (P = 0.04) and giant cells (P = 0.03) was associated with less drug being required to achieve healing. In contrast, necrosis was associated with a greater amount of drug to achieve healing (P = 0.05). The observed correlations between tissue responses and immune and clinical parameters provide further evidence for the role of antibody and other soluble mediators of the cellular immune response in the evolution of disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Truncus arteriosus and double aortic arch associated with DiGeorge syndrome.

We report the 1st known case in which truncus arteriosus and double aortic arch have been associated with DiGeorge syndrome. The association of these 2 cardiovascular anomalies lends support, by itself, to speculation that truncus arteriosus and double aortic arch have a common embryonic pathogenesis; and the presence of these anomalies in a patient with DiGeorge syndrome strengthens the contention that the common causative factor is pathologic development of the neural crest cells.

Journal Article↗
PubMed1991

Laboratory diagnosis of Leishmania.

Leishmaniasis should be considered in the differential diagnosis of individuals living in or with a history of having traveled to known endemic areas and who present with signs and symptoms of visceral infection or with cutaneous or mucosal lesions. Because leishmaniae are capable of producing a wide spectrum of disease in humans, the clinical manifestations overlap with many other diseases. Definitive diagnosis of Leishmania infection in the laboratory requires demonstration of the parasite in smears, in biopsies, or by isolation of the organism in culture media or in experimental animals. Many other methods for demonstration of parasites (histochemical and immunohistochemical) or for detecting the presence of antibodies against leishmaniae (serologic) have been described. Many advances have been made in these areas, but the methodology and the technology involved in immunohistochemistry and serology remain outside the reach of the standard clinical diagnostic laboratory, which both in developed and less developed countries still relies on demonstration of the parasites in smears stained with Giemsa stain and on biopsy specimens processed and stained with hematoxylin and eosin stain. The newer serologic techniques, such as ELISA with several variations, IFAT, and others, are largely research tools with the greatest use in seroepidemiologic surveys.

Animals↗
PubMed1990

[Tachyarrhythmia caused by paroxysmal atrial fibrillation following heat stress].

The Authors describe a case of paroxysmal atrial fibrillation, in young patients with apparently healthy hearts due to heat stress and expound the pathogenetic mechanisms. They point out the importance of a complete cardiologic examination: sometimes paroxysmal atrial fibrillation is an initial symptom of silent cardiovascular disease.

Adult↗
PubMed1989

The relationship of Leishmania braziliensis subspecies and immune response to disease expression in New World leishmaniasis.

Multivariate analyses of clinical presentation, subspecies identity of the causal organism, and the Leishmania-specific immune response parameters (indirect fluorescent antibody test [IFAT], cutaneous delayed type hypersensitivity [DTH], and in vitro lymphocyte transformation [LT]) of 441 patients with tegumentary leishmaniasis were used to examine the human host-parasite interaction in L. braziliensis infection. Mucocutaneous disease (P less than .002) and L. braziliensis braziliensis infection (P less than .001) were independently associated with significantly higher IFAT titers and cutaneous DTH than were cutaneous disease or L. braziliensis panamensis infection. Lesion size was also correlated with IFAT titer (P. less than .001). Although time of lesion evolution was highly correlated with all parameters, differences associated with subspecies and disease form were independent of lesion duration (three-way analysis of variance). In contrast with the cutaneous DTH response, the in vitro lymphocyte proliferative response to Leishmania antigen did not correlate with disease form and only weakly with infecting subspecies when time of evolution and subspecies were controlled. The association of mucosal disease presentation with a particular subspecies and the independent correlation of both variables with heightened IFAT titers and cutaneous DTH to Leishmania antigen supports the possibility of immune mechanisms of pathogenesis in human tegumentary leishmaniasis.

Analysis of Variance↗
PubMed1987

Radiation-induced polymerization for the immobilization of penicillin acylase.

The immobilization of Escherichia coli penicillin acylase (EC 3.5.1.11) was investigated by radiation-induced polymerization of 2-hydroxyethyl methacrylate at low temperature. A leak-proof composite that does not swell in water was obtained by adding the cross-linking agent trimethylolpropane trimethacrylate to the monomer-aqueous enzyme mixture. Penicillin acylase, which was immobilized with greater than 70% yield, possessed a higher Km value toward the substrate 6-nitro-3-phenylacetamidobenzoic acid than the free enzyme form (Km = 1.7 X 10(-5) and 1 X 10(-5) M, respectively). The structural stability of immobilized penicillin acylase, as assessed by heat, guanidinium chloride, and pH denaturation profiles, was very similar to that of the free-enzyme form, thus suggesting that penicillin acylase was entrapped in its native state into aqueous free spaces of the polymer matrix.

Amidohydrolases↗
PubMed1987

Results of reoperation for failure of cardiac bioprostheses.

A ten-year experience with reoperations for failure of cardiac bioprostheses is reported. 362 patients were operated for valve replacement with 412 bioprostheses. There were 35 (9.64%) reoperations for valve failure. Mean time between operation and reoperation was of 64.4 months. Operative mortality was 14.28%: 3 patients died for cardiac and 2 for extra-cardiac causes. Long-term mortality after reoperation was 6.25%. Morphological examination of the explanted bioprostheses confirmed the cause of bioprosthetic valve failure, due to calcific degeneration in 88.88% of case, to post-endocarditic rupture in 5.55% and to prosthetic thrombosis in 2.77%. The importance of timing reoperation is stressed in order to reduce the operative mortality. The conditions suitable for implantation of bioprostheses are listed.

Adolescent↗
PubMed1985

Paraneoplastic syndromes of the nervous system.

The paraneoplastic disorders of the nervous system are clinicopathologic syndromes that occur in association with systemic cancer. Dysfunction of any part of the nervous system or its effector organs may be produced by a paraneoplastic process. The temporal relationship between the onset of a paraneoplastic syndrome and the diagnosis of the associate cancer varies. Most of the paraneoplastic syndromes of the nervous system may appear months to years before the cancer is discovered. The pathogenesis of most of the paraneoplastic syndromes of the nervous system is unknown and specific, effective therapy is lacking. With rare exceptions, treatment of the associated cancer seldom alters the course of patients with these syndromes. However, in other paraneoplastic syndromes such as myasthenia gravis, myasthenic syndrome of Eaton-Lambert and polymyositis-dermatomyositis an autoimmune pathogenesis is established or strongly suspected.

Cerebellar Diseases↗
PubMed1984

Filariasis in Colombia: prevalence of Mansonella ozzardi in the Departamento de Meta, Intendencia del Casanare, and Comisaría del Vichada.

The prevalence and distribution of filarial infections among the inhabitants of adjacent regions of the Departamento del Meta, Intendencia del Casanare, and Comisaría del Vichada in northeastern Colombia was determined by collection and examination of blood samples using the Knott's method. Mansonella ozzardi, the only species detected, was found in 2.5% of the samples collected in Meta (6/243), in 4.9% from Casanare (12/247) and in 2.5% from Vichada (3/137). All of the microfilaria carriers were Indians who had migrated from other parts of eastern Colombia, principally from the interior of Meta and Vichada. These results indicate that filariases are not endemic in the regions examined, and suggest that influx of microfilaria carriers with sufficiently high microfilaremia could establish new foci of transmission in areas where appropriate vectors are abundant.

Colombia↗
PubMed1984

[Trans-septal catheterization. Technic and indications].

We report our experience with transseptal catheterization of the left side of the heart via the right femoral vein. This technique was attempted in 50 patients undergoing left heart catheterization for hemodynamic evaluation of aortic valve stenosis (15 patients) and prosthetic valves (35 patients). The importance of some manoeuvres, especially within the right atrium, to avoid some of the most usual complications, like cardiac or aortic perforations, intramyocardial injection of contrast medium, and embolization of left atrial masses, is underlined.

Cardiac Catheterization↗
PubMed1983

Filariasis in Colombia: prevalence and distribution of Mansonella ozzardi and Mansonella (=Dipetalonema) perstans infections in the Comisaría del Guainía.

A survey was conducted to determine the prevalence and distribution of filarial infections among the inhabitants of Comisaría. Approximately 25% of the 604 individuals bled (Knott's sample) harbored microfilariae; more men (29.7%) were infected than women (23.7%); approximately 6% were infected with Mansonella (=Dipetalonema) perstans, 13% with Mansonella ozzardi, and 7% with both filariae. Mansonella ozzardi was more common in men than in women, and its prevalence increased with age in both sex groups; it was detected in most of the resident ethnic groups but was most common in the Puinave and the Curripaco Indians, and appeared to be distributed throughout the Comisaría. The prevalence of M. perstans was essentially the same in men as in women, and in age-groups from the 2nd to 4th decade, although its tendency to increase with age was not as marked as in M. ozzardi infections. Mansonella perstans appeared to be limited to the central and southern regions of the Comisaría, was found principally in the Curripaco Indians, and was detected in settlements situated within the drainage of both the Río Orinoco and the upper Río Negro. Approximately 9% of the white settlers (colonos) harbored M. ozzardi, and 5% M. perstans. These results indicate that both M. perstans and M. ozzardi are endemic in the Comisaría del Guainía, and suggest that the focus of M. perstans may extend further into the South American continent along the Río Negro and its tributaries.

Adolescent↗