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Biomedical subjects

V Santos

Publications and source records attributed to V Santos.

At least 19 recordsLinked to original sources
PubMed2005

[A rare case of malabsorption of thyroid hormones].

We describe the case of a 22-year old male undergoing a total thyroidectomy for euthyroid multi-nodular goitre (TSH: 1.6 microUI/ml). He was discharged treated with LT4 100 mg id. After discharge, he went into full clinical and laboratorial hypothyroidism (TSH = 396 microUI/mL). We were able to rule out failure to take the medication and concomitant use of drugs. In the evaluation of intestinal absorption, only the D-Xylose test proved to be abnormal. After unsuccessful administration of oral T4 and T3, under close nursing supervision, intramuscular (IM) and subcutaneous (SC) forms of administration of T4 were experimented. While both forms achieved normal levels of thyroid hormones, we opted for IM injection as the patient complained of local pain during SC administration. This seems to be the second case described in which it was necessary to resort to parenteral administration of T4 to achieve clinical and laboratorial euthyroidism.

Absorption↗
PubMed2003

Recovery of lignin and furfural from acetic acid-water-HCl pulping liquors.

The feasibility of the HCl-water-acetic acid pulping technology (Acetosolv process) depends on the efficiency of solvent and byproduct recovery. Experimental data and computer simulation calculations are presented to assess these points. The recovery of precipitable, dissolved solids derived from lignin by mixing pulping liquors and water in various proportions was studied. Computer simulation of selected operational strategies enabling the recovery of furfural from the liquors obtained in the lignin-precipitation stage are also presented.

Acetic Acid↗
PubMed2003

Carboxymethylcellulose from totally chlorine-free-bleached milox pulps.

High purity cellulose pulp was obtained from Eucalyptus globulus wood by using an environmentally friendly delignification technique (Milox pulping) and subsequent bleaching by totally chlorine free technology. The pulp obtained under optimised experimental conditions was used for the manufacture of carboxymethylcellulose in a heterogeneous medium. By means of an experimental design, the effects of selected operational variables on the composition and chemical properties of reaction products from the carboxymethylation reaction were assessed for optimisation purposes. The distribution of the different carboxymethylglucose mole fractions (un-, mono-, di- and tri-substituted) was determined and compared with theoretical predictions. The maximum average degree of substitution (1.26) was determined at a NaOH/cellulose mole ratio of 4.8 and at a MCA/cellulose mole ratio of 2.0.

Carboxymethylcellulose Sodium↗
PubMed2001

Amelogenin-cytokeratin 14 interaction in ameloblasts during enamel formation.

The enamel protein amelogenin binds to the GlcNAc-mimicking peptide (GMp) (Ravindranath, R. M. H., Tam, W., Nguyen, P., and Fincham, A. G. (2000) J. Biol. Chem. 275, 39654-39661). The GMp motif is found in the N-terminal region of CK14, a differentiation marker for ameloblasts. The binding affinity of CK14 and amelogenin was confirmed by dosimetric binding of CK14 to recombinant amelogenin (rM179), and to the tyrosine-rich amelogenin polypeptide. The specific binding site for CK14 was identified in the amelogenin trityrosyl motif peptide (ATMP) of tyrosine-rich amelogenin polypeptide and specific interaction between CK14 and [(3)H]ATMP was confirmed by Scatchard analysis. Blocking rM179 with GlcNAc, GMp, or CK14 with ATMP abrogates the CK14-amelogenin interaction. CK14 failed to bind to ATMP when the third proline was substituted with threonine, as in some cases of human X-linked amelogenesis imperfecta or when tyrosyl residues were substituted with phenylalanine. Morphometry of developing teeth distinguished three phases of enamel formation; growth initiation phase (days 0-1), prolific growth phase (days 1-7), and growth cessation phase (post-day 7). Confocal microscopy revealed co-assembly of CK14/amelogenin in the perinuclear region of ameloblasts on day 0, migration of the co-assembled CK14/amelogenin to the apical region of the ameloblasts from day 1, reaching a peak on days 3-5, and a collapse of the co-assembly. Autoradiography with [(3)H]ATMP and [(3)H]GMp corroborated the dissociation of the co-assembly at the ameloblast Tomes' process. It is proposed that CK14 play a chaperon role for nascent amelogenin polypeptide during amelogenesis.

Acetylglucosaminidase↗
PubMed2001

Protective effect of intranasally inoculated Lactobacillus fermentum against Streptococcus pneumoniae challenge on the mouse respiratory tract.

Lactic acid bacteria are increasingly used to restore the ecological equilibrium of different mucosal areas in humans and/or animals. Likewise, they can be used to potentially protect against pathogenic microorganisms. In the present paper, the preventive effect of intranasally inoculated Lactobacillus fermentum against challenge with Streptococcus pneumoniae was studied, using a mouse experimental model. L. fermentum inoculated four times at a dose of 10(7) colony forming units per mouse was able to decrease the number of S. pneumoniae throughout the respiratory tract. The L. fermentum treatment increased the number of activated macrophages in lung slices, and a higher lymphocyte population in the tracheal lamina propria. S. pneumoniae challenge showed a typical response against pathogen with a higher non-specific immune response. Preventive treatment, i.e. L. fermentum administration prior to S. pneumoniae challenge, showed a response close to that of L. fermentum. Anti-S. pneumoniae antibodies increased in lactobacilli-treated animals compared to the non-treated lactobacilli mice. The increase in the antibody levels suggests that the mucosal immune system could be involved in the protective effect, accomplished with competitive exclusion, nutrient competition and production of inhibitory substances. This paper will be the basis for further studies of the protective effect of lactobacilli against S. pneumoniae in the respiratory tract.

Administration, Intranasal↗
PubMed2001

Ultrastructural studies on the respiratory tract of mice inoculated intranasally with L. fermentum.

The ultrastructural modifications of the respiratory tract of mice produced by the intranasally inoculated L. fermentum was evaluated. The genus Lactobacillus has been largely studied from the probiotic effect point of view in different ecological systems. Lactobacilli inoculated in 4 intranasal doses (1 x 10(9) CFU/dose) do not produce fundamental changes at the ultrastructural level in the organs of the respiratory tract studied. The most important finding was the presence of a cellular type with intracellular structures surrounded by membranes exhibiting electron dense paracristalline material parallel arranged.

Administration, Intranasal↗
PubMed2000

The prevalence of antibodies against desmoglein 1 in endemic pemphigus foliaceus in Brazil. Cooperative Group on Fogo Selvagem Research.

BACKGROUND: Pemphigus foliaceus is an autoimmune skin disease mediated by autoantibodies against desmoglein 1. The endemic form is thought to have an environmental cause. The Terena reservation of Limão Verde in Mato Grosso do Sul, Brazil, is a recently identified focus of the disease, with a prevalence of 3.4 percent in the population. We tested the hypothesis that normal subjects living in an endemic area have antibodies against desmoglein 1. METHODS: We used an enzyme-linked immunosorbent assay to detect antibodies against desmoglein 1 in serum samples from 60 patients with endemic pemphigus foliaceus (fogo selvagem) who lived in Limão Verde or elsewhere in Brazil, 372 normal subjects (without pemphigus foliaceus) from Limão Verde and surrounding locations, and 126 normal subjects from the United States and Japan. RESULTS: Antibodies against desmoglein 1 were detected in 59 of the 60 patients with fogo selvagem (98 percent) but in only 3 of the 126 normal subjects from the United States and Japan (2 percent). Antibodies were also detected in 51 of the 93 normal subjects from Limão Verde (55 percent) and in 54 of the 279 normal subjects from surrounding areas (19 percent). Serum samples obtained one to four years before the onset of disease were available for five patients; all five had antibodies in the initial serum samples, and the onset of disease was associated with a marked increase in antibody values. CONCLUSIONS: The prevalence of antibodies against desmoglein 1 is high among normal subjects living in an area among where fogo selvagem is endemic, and the onset of the disease is preceded by a sustained antibody response. These findings support the concept that the production of antibodies against desmoglein 1 is initiated by exposure to an unknown environmental agent.

Autoantibodies↗
PubMed2000

Trace element status (Se, Cu, Zn) and serum lipid profile in Portuguese subjects of San Miguel Island from Azores'archipelago.

Data on selenium, copper and zinc in serum of Portuguese inhabitants of the city of Ponta Delgada-Azores Archipelago are reported for the first time. The subjects are of both sexes, aged 20 to 60 years, and non-abusers of alcohol, tobacco or drugs. Serum concentrations of these elements are in the same range than those found for populations of Lisbon and of some other European countries. Differences between sexes are observed, with serum selenium and zinc levels being higher in males than in females, and the copper levels being higher in females as compared to males. These results can be explained by the hormonal status and/or oral contraceptive steroids intake, particularly for copper. Concerning lipid profile, the majority of individuals have serum lipid parameters within the normal range. In addition, no difference in trace element levels between normo and hyperlipidemic individuals is observed and no conclusive results about the relationship of all evaluated parameters to alcohol, tobacco and drug consumption are observed, in agreement with data obtained in the population of Lisbon.

Adult↗
PubMed1999

[Parinaud syndrome and Collier signal. Initial neurological manifestation in an HIV-1 positive patient].

We describe the third case in the literature of Parinaud's syndrome as the sole manifestation of brainstem toxoplasmosis, in a positive HIV-1 patient and review the literature concerning the possible etiologies of Parinaud's syndrome, enforcing that it is a rare manifestation of central nervous system toxoplasmosis. We refer to its occurrence without simultaneous obstructive hydrocephalus and increased intracranial pressure, pointing out the Collier signal which is not very well known, but has great semiotic value once it locates the lesion in the brainstem.

AIDS-Related Opportunistic Infections↗
PubMed1998

Production of carotenoids by phaffia rhodozyma growing on media made from hemicellulosic hydrolysates of eucalyptus globulus wood

Phaffia rhodozyma NRRL Y-17268 cells were proliferated in xylose-containing media made from Eucalyptus wood. Wood samples were subjected to acid hydrolysis under mild operational conditions, and hydrolysates were neutralized with lime. Neutralized hydrolysates were treated with charcoal for removing inhibitors and then supplemented with nutrients to obtain culture media useful for proliferation of the red yeast P. rhodozyma. A set of experiments carried out in orbital shakers proved that hydrolysates containing 16.6 g xylose/L supplemented only with 3 g peptone/L performed well as fermentation media. At the end of experiments, xylose was depleted and 10.5 g cells/L were obtained. Biomass was highly pigmented and volumetric carotenoid concentrations up to 5.8 mg carotenoids/L (with 4.6 mg astaxanthin/L) were reached. Further experiments in batch fermentors using concentrated hydrolysates (initial xylose concentrations within 16.6 and 40.8 g/L) led to good biomass concentrations (up to 23.2 g cells/L) with increased pigment concentration (up to 12.9 mg total carotenoids/L, with 10.4 mg astaxanthin/L) and high volumetric rates of carotenoid production (up to 0.079 mg/L.h). Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed1996

Development of a generalized phenomenological model describing the kinetics of the enzymatic hydrolysis of NaOH-treated pine wood.

Pinus pinaster wood samples were treated during 3 h with alkaline solutions (containing 1, 5.5, or 10 weight percent NaOH) at 100, 115, or 130 degrees C using liquor/wood ratios of 6, 8, or 10 g/g. The solid residues obtained in treatments were used as substrates for enzymatic hydrolysis. In the hydrolysis assays, the reaction time (in the range 0-48 h) was considered as an operational variable. The cellulose conversion achieved at the end of assays were highest for samples pretreated at high temperature and high alkali concentration using low liquor/wood ratios. The experimental results obtained in each hydrolysis trial were fitted to an empirical model based on the assumption that the cellulose contained in substrates was composed by two fractions having different susceptibility to hydrolysis. The kinetic parameters obtained for the various experiments performed were correlated with the operational variables by means of empirical, statistically significant equations, which provided a generalized interpretation of the process.

Enzymes↗
PubMed1995

Cost implications of event recordings in apnea/bradycardia home monitoring: a theoretical analysis.

OBJECTIVES: To evaluate the financial impact of incorporating event recordings as an integral component of home apnea/bradycardia monitoring. STUDY DESIGN: This theoretical analysis examines the cost of home monitoring when medical decisions are based on an evaluation of the cardiorespiratory waveforms surrounding each apnea/bradycardia monitor alarm (documented monitoring) compared to those based on parental observations. Data for both approaches were obtained from 155 infants referred within the first 10 days of life, because a sibling died of sudden infant death syndrome. All were followed on an impedance type apnea/bradycardia monitor with an attached event recorder. The monitor settings were 20 seconds for apnea and 80 beats per minute (bpm) for bradycardia. Parents were taught how to use the equipment, resuscitative techniques, and to complete an alarm log. The clinical protocol provided for home monitoring until there were no "episodes" (prolonged apnea or prolonged bradycardia) for 16 consecutive weeks. A polysomnogram would be obtained if an "episode" occurred. For each infant two independent approaches were used to judge the occurrence of an "episode": (1) parental report of an apnea alarm occurring during sleep or a physiologic alarm associated with skin color change or resuscitative intervention and (2) apnea > or = 20 seconds long or bradycardia > or = 10 seconds. The cost was calculated assuming a 4-week monitor rental fee of $350, a 4-week waveform interpretation fee of $180, and a $600 fee for performing and interpreting a polysomnogram. RESULTS: Episodes defined from an interpretation of the cardiorespiratory waveforms resulted in fewer diagnostic studies, a shorter period of home monitoring, and lower per patient treatment costs. CONCLUSION: Despite the increased monthly cost, incorporating event recordings as an integral component of home monitoring resulted in a lower average per patient cost.

Apnea↗
PubMed1994

Specific transforming growth factor-beta subtypes regulate embryonic mouse Meckel's cartilage and tooth development.

Members of the transforming growth factor-beta (TGF-beta) superfamily have emerged as critical regulators for cell growth and differentiation. Whereas the different TGF-beta subtypes are equipotent in the majority of biological assays using cell lines cultured in vitro, there are indications that in more complex systems involving epithelial-mesenchymal interactions, the TGF-beta subtypes differ in their biological activities. To test the hypothesis that TGF-beta subtypes specifically regulate either Meckel's cartilage or tooth morphogenesis, we designed experiments to compare loss of function effects of TGF-beta 1, TGF-beta 2, and TGF-beta 3 subtypes using a serumless, chemically defined medium to culture embryonic mouse E10 (42-44 somite pairs) mandibular explants. The major effect of loss of function resulting from abrogation of TGF-beta 1 using antisense treatment resulted in a 20% increase (P < 0.05) in chondrocyte number, a decrease in extracellular matrix, and dysmorphology of the rostral region of Meckel's cartilage. Exogenous TGF-beta 1 provided indistinguishable recovery to the normal phenotype. TGF-beta 2 antisense treatment produced a threefold enlargement (P < 0.05) of tooth organs and advanced their development to the cap stage. TGF-beta 2 provided recovery to the normal phenotype (e.g., reduced tooth size and development to the bud stage), whereas TGF-beta 1 or TGF-beta 3 polypeptides had no effect. TGF-beta 3 antisense treatment resulted in a reduction of approximately 15% in the length of Meckel's cartilage. We interpret these results to suggest that TGF-beta 1 functions to regulate the number of chondrogenic cells, the amount of extracellular matrix, and the rate of developmental assembly of the rostral to posterior segments in forming Meckel's cartilage. TGF-beta 2 appears to regulate tooth size and stage of development without affecting cartilage. TGF-beta 3 appears to regulate Meckel's cartilage size without altering tooth size or shape. The results are discussed in terms of the regulatory functions of the TGF-beta subtypes during embryonic craniofacial morphogenesis.

Animals↗
PubMed1993

Messenger RNA phenotyping for semi-quantitative comparison of glucocorticoid receptor transcript levels in the developing embryonic mouse palate.

A specific complex of glucocorticoid and receptor interacts with responsive genes in target tissues of developing palate and controls its morphogenesis. In order to examine developmental changes in glucocorticoid receptor gene expression during embryonic palate formation, variations in transcript levels have been determined using a simple semi-quantitative reverse transcription-polymerase chain reaction (PCR) procedure. Oligo (dT)16 was used as the primer for reverse transcription, and the amount of PCR product for glucocorticoid receptor was normalized against those for glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-actin. We found that either GAPDH or beta-actin were suitable internal standards, and that the mRNA levels of glucocorticoid receptor undergoes a significant decrease of 30% at the developmental stage of embryonic mouse palatal shelf re-orientation. Immunolocalization of the receptor demonstrated a significant change in the distribution pattern of glucocorticoid receptor during the re-orientation stage of secondary palate formation. Our present data suggest that developmental variations in glucocorticoid receptor level control morphogenetic events of secondary palate formation.

Animals↗
PubMed1993

Antisense inhibition of AMEL translation demonstrates supramolecular controls for enamel HAP crystal growth during embryonic mouse molar development.

During tooth development, enamel organ epithelial cells express a tissue-specific gene product (amelogenin) which presumably functions to control calcium hydroxyapatite crystal growth patterns during enamel biomineralization. The present studies were designed to test the hypothesis that amelogenin as a supramolecular aggregate regulates crystal growth during enamel biomineralization. Antisense oligodeoxynucleotide strategy was used in a simple organ culture system to inhibit amelogenin translation. Under these experimental conditions, antisense treatment prior to and during amelogenin expression resulted in inhibition of amelogenin translation products within immunoprecipitated [35S]methionine metabolically labeled proteins. To determine the efficiency of antisense treatment in this model system, digoxigenin-labeled oligodeoxynucleotides were observed to diffuse throughout the tooth explants including the target ameloblast cells within 24 hours. Ultrastructural analyses of amelogenin supramolecular assembly as electron-dense stippled materials in antisense treated cultures demonstrated dysmorphology of the extracellular enamel matrix with a significant reduction in crystal length and width. We conclude that secreted extracellular proteins form a supramolecular aggregate, which controls both the orientation and dimensions of enamel crystal formation during tooth development.

Amelogenesis↗
PubMed1992

Desmin expression during early mouse tongue morphogenesis.

Occipital somites provide progenitor cells for craniofacial muscle development including the tongue musculature. Serum-derived factors are assumed to be pre-requisite for myogenesis in vitro. To test these assertions, we designed experiments to determine whether early mouse tongue development in general, and desmin localization in particular, were expressed during the development of embryonic mouse first branchial arch explants cultured in serumless, chemically-defined medium. Immunohistochemical techniques determined the chronology and positions of desmin expression during early craniofacial development. Occipital somites expressed desmin at E9 (9 days +/- 2 h post-fertilization, 18-20 somites). A discrete cell migration pathway initiating in the somites and terminating in the lateral lingual processes of the tongue primordium was defined based upon desmin expression patterns in E9-E11 embryos and computer-assisted three dimensional reconstructions. The in vitro model system was permissive for tongue morphogenesis, allowing development and fusion of the lateral lingual processes with the tuberculum impar. During culture myoblasts were not observed to fuse into myotubes with sarcomeric assembly, even though explant myoblasts produced muscle-specific protein. E10 explants cultured for 9 days demonstrated a five-fold increase in cell number that expressed desmin (P less than 0.05) when compared to the E10 starting material. We interpret these results to indicate that the tongue myogenic cell lineage was determined between E8 and E11, and that this resident population expanded within explants cultured in serumless medium by several explanations: (i) cells other than progenitor myoblasts (e.g., satellite cells) were induced to become myoblasts, and/or (ii) progenitor myoblasts within the original explants expanded by cell division in the absence of serum factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Giant cell variant of malignant fibrous histiocytoma of the head and neck.

The giant cell variant of malignant fibrous histiocytoma is a rare entity in head and neck. Only eight well documented cases of this type are reported in the English literature. These tumours affect the superficial and deep structures of the neck most often and are best treated with prompt radical surgery. The prognosis of the giant cell type of malignant fibrous histiocytoma is dependent on the location of the tumour, with superficial tumours having a much better outlook.

Female↗