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Biomedical subjects

N Santiago

Publications and source records attributed to N Santiago.

18 recordsLinked to original sources
PubMed2003

[Iatrogenic tracheal stenosis following endotracheal intubation: a study of 20 clinical cases].

The authors report a case review series of 20 patients with tracheal stenosis after prolonged oral or nasotracheal intubation who underwent surgical treatment between 1995 and 1999. Seventeen were male (85%) and three (15%) were female. The age varied between 9 and 68 years (32.8 +/- 14.9 years). The stenotic area of the airway was limited to the trachea, and its length varied between 2 and 5 cm (3.3 +/- 1.2 cm.). All patients were treated surgically with an external approach for reconstruction after stenosis ablation. Follow up was at three and six months after surgery there were: 16 cases with (80%) good results, two (10%) with satisfactory results and two unsatisfactory (10%). We found a statistically significant correlation (Spearman correlation) of 5% level between the period of tracheal intubation and patient's age (R = 0.478, p = 0.033).

Adolescent↗
PubMed2002

Morphology of trachea in benign human tracheal stenosis: a clinicopathological study of 20 patients undergoing surgery.

Prolonged tracheal intubation of patients often leads to tracheal stenosis (TS), which may require surgical removal of the narrowed portion of the airway. We studied 20 patients with TS who underwent surgical ablation of the stenotic portion of trachea. The morphology of the tracheal segments was characterized and compared with clinical data and with the prognosis for the disease. We found that TS was usually due to an increase in the width of the mucosa as a result of the fibrosis associated with the chronic inflammation. Plasma cells were the predominant leukocyte type seen in the inflammatory infiltrates of the surgically removed portions of narrowed trachea. In the majority of TS samples, the epithelial surface was intact and presented cilia; in contrast, cilia disappeared when the tracheal lumen was completely obliterated. Mucosal cells and glands were also well preserved in TS samples. The need to remove TS segments was often related to previous tracheal surgery, which was also associated with closing of the tracheal lumen and ossification of cartilage rings. We conclude that (a). chronic inflammation and fibrosis are responsible for the narrowing of trachea in TS patients, (b). metaplastic ossification of cartilage rings only occurs after complete obliteration of the tracheal lumen, and (c). loss of cilia and presence of metaplastic bone tissue are indicators of a poor prognosis for TS.

Adult↗
PubMed2001

Mixed germ cell tumor in the eye of a dog.

A 3-year-old female neutered Staffordshire Bull Terrier presented with a mixed germ cell tumor involving the base of the iris and the ciliary body of the right eye. The tumor mass was composed primarily of packeted vacuolated, polygonal (hepatoid) cells and small round cells; epithelial cells lining tubuloacinar structures were a less prominent component. The hepatoid and round cells stained positively for alpha-fetoprotein and cytokeratin. The epithelial cells stained positively for cytokeratin only, and some contained cytoplasmic mucin droplets. The polygonal cells were interpreted as a hepatoid variant of yolk sac tumor, and the epithelial cells were considered a teratomatous component. Trabeculae of bone were observed within the mass and may have been metaplastic or a teratomatous element. Extragonadal germ cell tumors are rare in dogs and have previously been reported only in the suprasellar region. This is the first report of this tumor type in the eye of a nonhuman species.

Animals↗
PubMed2001

Hepatitis C patients in Puerto Rico have an altered iron balance.

Iron overload is a major concern in hepatitis C virus (HCV) infection because excess iron can promote hepatocyte damage by activating iron-mediated lipid peroxidation. This may also facilitate viral replication. The objective of this pilot study was to test the hypothesis that Puerto Rican HCV patients have an altered serum iron (SIR) profile. Twenty-three HCV patients and 38 non-HCV controls were compared in terms of their serum iron, iron-binding capacity, percent saturation of transferrin, available binding capacity, and ferritin. Statistically significant differences (p < 0.01, Student's t-test) were found between the HCV patients and the non-HCV controls for SIR, transferrin saturation, and ferritin. The mean SIR concentration and transferrin saturation were 25% higher in HCV patients relative to controls. HCV patients had a mean ferritin value 48% higher than controls. These pilot study data indicate that Puerto Rican HCV patients have an altered iron balance and may be more susceptible to iron-induced oxidative stress.

Case-Control Studies↗
PubMed1998

Acylated non-alpha-amino acids as novel agents for the oral delivery of heparin sodium, USP.

Ten N-acylated, non-alpha-amino acids have been prepared as oral delivery agents and used to demonstrate the oral delivery of heparin in vivo in rats and primates. Following the oral administration of solutions containing a combination of heparin and a delivery agent to rats or primates, significant plasma heparin concentrations were evidenced by APTT and anti-Factor Xa assays. The estimated pharmacodynamic equivalence for an oral dosing solution containing heparin and a delivery agent is 39% in primates. In vitro experiments based on heparin affinity chromatography or heparin/methylene blue complexation were also performed to begin investigation of the mechanism by which these compounds facilitate heparin oral delivery. Results of in vitro studies suggest that absorption of the drug across the gastrointestinal membrane is the result of a non-covalent interaction between heparin and the delivery agent.

Administration, Oral↗
PubMed1996

Oral immunization with a model protein entrapped in microspheres prepared from derivatized alpha-amino acids.

A model antigen, ovalbumin (OVA), was encapsulated in microspheres prepared from derivatized alpha-amino acids and administered orally to mice. These microspheres are quickly and easily prepared, without the use of organic solvents, high temperatures, or complex purification techniques. Immunological responses included induction of OVA-specific antibodies in both sera (IgG) and in intestinal secretions (sIgA), as well as antigen-dependent proliferation of splenic CD4+ T cells following, in some cases, as little as a single oral priming dose containing 0.1 mg OVA. Oral administration of microspheres was also found to be effective as a secondary immunization following a subcutaneous prime with soluble antigen. In addition, the protective effect of co-encapsulation of cholera toxin, a mucosal adjuvant, was demonstrated in a whole virus model (infectious bursal disease in chickens). These results indicate that oral administration of antigen-loaded derivatized alpha-amino acid microspheres can induce local and systemic antibody production and/or stimulation of effector cells.

Administration, Oral↗
PubMed1995

N-acylated alpha-amino acids as novel oral delivery agents for proteins.

A series of N-acylated alpha-amino acids were synthesized and shown to improve the oral delivery of two protein drugs, salmon calcitonin (sCT) and interferon-alpha. Forty-five compounds in this series were tested in vivo in rats and primates. A significant positive correlation was found between the log P of the acylated amino acids and the decrease in serum calcium following oral dosage of sCT in rats. Such a correlation was not found for interferon-alpha. These derivatized amino acids only weakly inhibited the activity of trypsin or leucine aminopeptidase. Histological examinations of rat intestinal tissue after oral dosing of acylated amino acid/protein combinations revealed no detectable pathology.

Acylation↗
PubMed1994

Stability study of drug-loaded proteinoid microsphere formulations during freeze-drying.

Drug-loaded proteinoid microspheres were freeze-dried to facilitate shipping and handling and to enable long term storage. Heparin was chosen as the model drug in developing the optimum lyophilization process. The factors influencing the integrity of either heparin-loaded or unloaded ('empty') proteinoid microspheres during freeze-drying were determined, with emphasis on: selecting an optimum freezing and resuspending temperature; choosing an appropriate cryoprotectant and its optimum concentration in the formulation; and, designing a suitable method for formulating the microspheres. Freezing at/below -70 degrees C was found to minimize damage to the microspheres. Addition of sugars, such as trehalose and lactose, as cryoprotectants, further increased the stability of the heparin-loaded microspheres during freeze-drying. The optimum trehalose or lactose concentrations were determined to be 5% (w/v). Using the optimumized lyophilization process described in this manuscript, microspheres remained intact during freeze-drying. The freeze-dried microspheres were stable for at least three months post-lyophilization.

Cryoprotective Agents↗
PubMed1993

Oral immunization of rats with proteinoid microspheres encapsulating influenza virus antigens.

Influenza virus antigen microspheres were prepared by a pH-dependent process using a protein-like polymer (proteinoid) made by thermal condensation of amino acids. The efficacy of these preparations to induce specific IgG responses when used as oral vaccines in rats was evaluated. A single enteric dose of M1 entrapped in proteinoid microspheres was able to induce a significant IgG response to M1 as early as 2 weeks postdosing, while rats dosed orally with the same M1 total dose (no microspheres) showed no detectable antibody response. An unencapsulated hemagglutinin and neuraminidase (HA-NA) preparation induced a moderate anti HA-NA IgG response. A single enteric dose of HA-NA spheres induced a response in 33% of the rats; this response was up to eight times higher than that observed in the rats dosed with unencapsulated antigen.

Administration, Oral↗
PubMed1990

Electroimmunoblotting of neuropeptide Y: application to the rat vas deferens.

In this study we have optimized the electroimmunoblotting conditions for neuropeptide Y (NPY). NPY standards and samples extracted from the rat vas deferens were separated on urea-sodium dodecyl sulphate gels. Densitometric scanning of the Coomassie Blue-stained gels allow a semi-quantitative analysis of NPY in the range of approximately 10(-11) to 10(-8) mol of NPY. Electroimmunoblotting of NPY was also shown to be best achieved overnight at 4 degrees C and with NC membranes of 0.22 micron. Under these conditions NPY extracted from the vas deferens has been efficiently electroimmunoblotted. Higher molecular weight NPY-reactive peptides were also detected that may be related to proteolytic processing of the NPY precursor.

Animals↗
PubMed1988

Antibody profiles by EITB and ELISA of cattle and sheep infected with Fasciola hepatica.

In evaluating potential mechanisms of immunity in fascioliasis we compared the time-course analysis of the antibody responses between a resistant (cattle) and a susceptible model (sheep). Sera from sheep and cows experimentally infected with F. hepatica were reacted with both somatic (FhWWE) and excretory-secretory (ES) antigens in order to evaluate the antibody repertoires in the 2 different hosts. Analysis of these sera by ELISA showed a significant increase in antibody levels by 2 wk in most infected cattle using both somatic and ES antigens, whereas with most infected sheep antibodies are not clearly detected until week 4. By EITB, both infected sheep and cows recognize major somatic polypeptides in a molecular weight range of 30-38 kDa by 8 wk. Cattle recognized 3 additional major antigens of 56, 64, and 69 kDa as early as 6 wk. Various polypeptides of 20-25 kDa are prominently detected by most sheep and very faintly, if at all, by the cow sera. The sera from both sheep and cows also identify ES polypeptides of 20-28 kDa. The patterns of polypeptides recognized by sheep infected with S. mansoni and challenged with F. hepatica in EITB are almost identical to those with a simple F. hepatica primary infection. No significant differences were detected in the antibody kinetics in ELISA between these 2 groups. Differences and similarities between these models could eventually help determine which antibodies may be predictive of resistance or susceptibility in fascioliasis.

Animals↗
PubMed1988

Evaluation of immunodiagnostic antigens in the excretory-secretory products of Fasciola hepatica.

The metabolic antigens of F. hepatica have been shown to be a source of potential immunodiagnostic antigens. We have fractionated F. hepatica excretory-secretory (ES) antigens by conventional gel filtration and HPLC, analyzed these fractions in PAGE, and evaluated their immunogenicity by ELISA with sera from experimentally infected rabbits to identify potential serodiagnostic antigens for fascioliasis. A fraction enriched in high molecular weight components of ca. 150-160 kDa was found to be very reactive with sera from early fascioliasis. This fraction was successfully adapted to the DOT-ELISA, where titers up to 1:16,000 still appeared visually as positive. Both acute and chronic fascioliasis sera also recognized, in the enzyme-linked immunoelectrotransfer blot technique (EITB), prominent 25-30-kDa polypeptides that have previously been shown to be recognized by infected rabbits, cows, and sheep. We have therefore employed conventional gel filtration and HPLC gel exclusion chromatography as a 1-step procedure to obtain fractions enriched in antigens recognized in early fascioliasis. In addition, these antigens have been successfully applied to a sensitive, visual immunodiagnostic technique that can be easily employed in field studies.

Animals↗
PubMed1986

Isolation of potential serodiagnostic Fasciola hepatica antigens by electroelution from polyacrylamide gels.

In the present study a partially purified antigen preparation enriched in Fasciola-specific antigens (designated p3 and 4) was used in the enzyme-linked immunoelectrotransfer blot (EITB) to identify polypeptides which induce antibody formation in acute fascioliasis. The pattern of antigens recognized by the sera of infected rabbits, humans, and cows was also compared. Similar but not identical patterns of recognition were obtained for the different models tested; the main antigenic polypeptides recognized were in clusters within 27-38, 18-23, and 11-14 Kd molecular weight (Mr) ranges. An antigen of 31-33 Kd was one of the most prominently recognized by all of the acute infection sera tested. This antigen, as well as those in the 18-23 Kd range, appear to have good specificity, as they are not recognized by antibodies to S. mansoni or P. westermani adult worm extracts. To further characterize and evaluate these low Mr antigens, we have isolated polypeptides by electrophoresing p3 and 4 F. hepatica antigens in 10%-15% gradient gels, identifying the desired Mr range with prestained markers, cutting individual gel strips, and then isolating them by electroelution. Antigen fractions of 19-23 and 31-33 Kd were isolated in this manner, re-electrophoresed, transferred to nitrocellulose and found to be reactive with the sera from a rabbit with acute fascioliasis. At least one of these antigens, of 20 Kd Mr, has been obtained by this means with a high degree of purity. This, as well as other antigen fractions isolated, showed high absorbance values in ELISA when reacted with the serum from a rabbit with an 8-week-old F. hepatica infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Identification of functional Fasciola hepatica antigens in experimental infections in rabbits.

Studies done comparing the reactivity of serum from an infected rabbit at different intervals of infection with a Fasciola hepatica crude tegument extract, F. hepatica excretory-secretory (ES) products and Fh arc 2 by ELISA show that the first 2 antigen preparations offer a better sensitivity for detecting acute infection, especially in its early stages (3 weeks). The ES proteins from F. hepatica adult worms were identified by the enzyme-linked immunotransfer blot (EITB) in order to define the antigens recognized by the sera from rabbits with experimental fascioliasis. A group of 7 polypeptides with molecular weights of 23-28 Kd were the major antigens recognized. Reactivity to these antigens is maximum at 8-10 weeks of infection by EITB. As the infection progresses, reactivity to the 23-28 Kd antigens decreases but does persist through 52 weeks of infection. At least 5 other polypeptides of 120, 84, 58, 52, 39 and 33 Kd were recognized by the sera of infected rabbits from 6 to 52 weeks of infection. A different pattern was observed in parallel studies done with these same sera by immunoprecipitation of ES antigens. In addition to a 33 Kd antigen, which was detected by both techniques, a 62 Kd antigen was detected early in infection (5 weeks) and 3 major antigens of 38, 40 and 44 Kd were prominent by immunoprecipitation from 9 weeks onward. This implies the presence of multiple Fasciola antigens with serodiagnostic potential. The expression of these antigens during development and their possible role in immunity is discussed.

Animals↗
PubMedDate not supplied

[Parapharyngeal space tumors. Our experience. I.P.O. Francisco Gentil, Lisbon].

Primary parapharyngeal space tumours are rare, representing only a 0.5% of head and neck neoplasms. The authors report a case series review of 38 patients with parapharyngeal tumours who underwent surgical excision between 1975 and 1998. Twenty-six of them were female (68%) and twelve male (32%). Thirty-three tumours (87%) were benign and five (13%) were malignant being the Pleomorphic adenoma the most common neoplasm (39%). All patients were treated surgically: the trans-cervical approach was used in 19 cases, cervical-parotid in 5, the trans-parotid approach in 7 patients, transoral in 5, the cervical-parotid approach with mandibulectomy in 2 and the combined transoral-cervical approach in 1 case. Out of the 33 patients with benign neoplasms, 1 (a pleomorphic adenoma treated through a transoral approach) had a recurrence. Amongst the 5 with malignant disease, recurrence or persistent local tumour was seen in 4 cases; and of these, 3 with persistent local tumour after incomplete excision died.

Adenoma, Pleomorphic↗
PubMedDate not supplied

T-cell rich B-cell lymphoma masquerading as Hodgkin disease: excellent outcome to inadequate therapy.

T-cell rich B-cell lymphomas (TCRBCL) are characterized as non-Hodgkin lymphomas with a minor population of malignant B-cells scattered among predominant, reactive T-lymphocytes. This entity can easily be confused with lymphocyte-predominant Hodgkin disease (HD-LP), resulting in inappropriate therapy and a poor outcome. Because of their similarity, the pathology of patients treated for HD-LP with an inadequate or short-lived response to therapy should always be reviewed by an expert hematopathologist. We describe the first reported patient in Puerto Rico with TCRBCL, originally diagnosed and treated as HD-LP. Although the patient received partial, substandard therapy for TCRBCL, an excellent prolonged complete response ensued, thus, giving further credence to the fact that malignant lymphomas and TCRBCL in particular, are a protean group of disorders which should be precisely and accurately classified before the proper therapeutic strategies can be outlined.

Adult↗