Search PubMed⌕ Search

Biomedical subjects

A Santos

Publications and source records attributed to A Santos.

At least 127 records · Page 7Linked to original sources
PubMed1997

Low-dose oral contraceptives and 24-hour ambulatory blood pressure.

OBJECTIVE: To evaluate in normotensive women the influence of low-dose oral contraceptives (OC, monophasic formulations containing 30 microg of estrogen) on 24-h blood pressure. METHODS: We evaluated prospectively in 15 normotensive healthy women (three smokers) the influence of OC on 24-h ambulatory blood pressure monitoring (ABPM). ABPM was performed (SpaceLabs 90207) before and after 6-9 months of use of OC. We also evaluated ABPM in eight women (two smokers) before and after 6-8 months on an intrauterine device (IUD) as contraceptive method--these were used as control subjects. RESULTS: OC produced a significant increase in 24-h ABPM values (from 120+/-3/75+/-2 to 128+/-4/81+/-2 mmHg, P < 0.04) which was particularly evident for night-time values (from 108+/-2/64+/-2 to 120+/-4/73+/-2 mmHg, P < 0.02). After OC, two normotensive women developed 'hypertensive values'. In OC users there was a slight but significant increase in body weight which did not correlate with the increase of blood pressure. In contrast, in the control group (IUD) neither ABPM values nor weight were modified by the contraceptive maneuver. CONCLUSIONS: In normotensive women, low-dose OC may increase blood pressure to an extent that, at least in some women, may affect blood pressure control towards 'hypertensive values'. This stresses the importance of monitoring blood pressure values during OC treatment.

Adult↗
PubMed1997

Neutral and acid mucins and eosinophil and argyrophil crystalloids in carcinoma and atypical adenomatous hyperplasia of the prostate.

Neutral and acid mucins and eosinophil and argyrophil crystalloids were studied in the glandular intraluminal contents of 130 prostatic carcinomas (PCa) and 22 atypical adenomatous hyperplasias (AAH). Specimens were studied in the usual extension for diagnostic purposes and considered positive when minimal amounts of mucin or any crystalloid were present. Some amount of altered secretion was seen in 110 PCa (84.6%) and in 17 AAH (77.3%); the similarity of the figures speaks for the close relationship of these lesions. The relative incidences in PCa/AAH were 61.5%/77.3% for neutral mucin, 80%/54.5% for acid mucin (p < 0.01), 25.4%/50% for eosinophil crystalloids (p < 0.02), 44.6%/9.1% for argyrophil crystalloids (p < 0.01) and 57%/36% for a compound secretion. The incidence of eosinophil crystalloids was greater in AAH and inversely proportional to the Gleason grade in PCa. The incidence of acid mucins and argyrophil crystalloids was higher in PCa and directly proportional to the tumour grade in all but the poorly differentiated ones. It is therefore suggested that AAH positive for acid mucins or argyrophil crystalloids be classified in the high grade AAH group.

Aged↗
PubMed1997

Displaying human interleukin-2 on the surface of bacteriophage.

Previous attempts to produce active human Interleukin-2 (hIL-2) in E. coli have failed, due to its aggregation in the form of cytoplasmic inclusion bodies, and the inability of the protein to enter the periplasmic export pathway, when fused to bacterial signal sequences. We have reasoned that these limitations could be overcome by introducing changes in the signal sequence and/or in some hIL-2 residues, not critical for its biological activity; and proceeded to test this hypothesis using a phagemid vector carrying the pelB secretion signal sequence, and the filamentous phage display system. Deletion of the Pro +2 in hIL-2 led to the export of a correct size (processed) molecule to the bacterial periplasm of Su- cells by the phagemid vector. However, this was achieved under growth conditions that would not favor phage assembly in Su+ strains. Changing the hydrophobic core of the leader peptide reversed this situation and allowed phage assembly and display of a pIII/hIL-2 hybrid protein in TG1 cells. The phage-displayed hIL-2 is correctly folded, as judged by its ability to interact with a conformation-specific anti-hIL-2 monoclonal antibody, and maintains its biological activity when tested in a CTLL-2 cell proliferation assay. The changes introduced in hIL-2 and the signal sequence will make possible to use the powerful phage display technology for the selection of high-affinity variants from libraries of hIL-2 mutants.

Amino Acid Sequence↗
PubMed1997

Evaluation of autofocus functions in molecular cytogenetic analysis.

This work describes a systematic evaluation of several autofocus functions used for analytical fluorescent image cytometry studies of counterstained nuclei. Focusing is the first step in the automatic fluorescence in situ hybridization analysis of cells. Thirteen functions have been evaluated using qualitative and quantitative procedures. For the last of these procedures a figure-of-merit (FOM) is defined and proposed. This new FOM takes into account five important features of the focusing function. Our results show that functions based on correlation measures have the best performance for this type of image.

Algorithms↗
PubMed1997

Assessment of renal dopaminergic system activity during the recovery of renal function in human kidney transplant recipients.

BACKGROUND: The urinary excretion of free dopamine has been used as an index of the renal synthesis of amine. However, it is now well recognized that in the kidney, newly-formed dopamine is significantly inactivated through deamination to 3,4-dihydroxyphenylacetic acid (DOPAC) by monoamine oxidase (MAO). The aim of the present study was to assess the renal dopaminergic system activity during the recovery of renal function in kidney transplant recipients and to assess which parameters are appropriate for the evaluation of renal amine synthesis under these conditions. METHODS: Twenty-four-hour urinary excretion of L-DOPA, dopamine and its metabolites (DOPAC; 3-MT; HVA) were continuously monitored in 19 renal transplant recipients from the first day of surgery until the twelfth day post-transplantation. RESULTS: In 11 patients (Group 1), renal function consistently recovered throughout the study (plasma creatinine levels decreased from 6.2 +/- 0.4 to 2.1 +/- 0.1 mg/dl). Eight patients presented with acute tubular necrosis (Group 2) and minimal renal function was maintained until the twelfth post-operative day. The urinary excretion of L-DOPA did not differ throughout the study between the two groups of patients. In contrast, the 24-h urinary levels of dopamine, DOPAC and HVA were significantly higher throughout the study in patients of Group 1: dopamine (Group 1, 179 +/- 26 to 422 +/- 51 nmol/24 h; Group 2, 25 +/- 3 to 57 +/- 13 nmol/ 24 h), DOPAC (Group 1, 698 +/- 57 to 3487 +/- 414 nmol/ 24 h; Group 2, 158 +/- 22 to 1014 +/- 193 nmol/24 h) and HVA (Group 1, 13,058 +/- 1199 to 20,387 +/- 1559 nmol/ 24 h; Group 2, 4140 +/- 848 to 15,219 +/- 1037 nmol/24 h). CONCLUSIONS: The recovery of renal function in renal transplant recipients is accompanied by an enhanced ability to synthesize dopamine and inactivate it to DOPAC and HVA. It is suggested that the urinary levels of DOPAC may be a useful parameter for the assessment of dopamine formation in renal tissues.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1997

Management of endophthalmitis in a silicone oil-filled eye.

PURPOSE: To describe the management of endophthalmitis in an eye filled with silicone oil for prolonged internal retinal tamponade. METHODS: A patient with a silicone oil-filled eye developed endophthalmitis postoperatively. Results of clinical examination, diagnostic procedures, and surgical management are described. RESULTS: Removal of the silicone oil, injection of antibiotics into the fluid-filled vitreous cavity, and reinjection of silicone oil resulted in resolution of the endophthalmitis and improvement in vision. CONCLUSIONS: Aggressive management of endophthalmitis in an eye requiring silicone oil tamponade may salvage useful vision.

Anti-Bacterial Agents↗
PubMed1997

Effect of salt on the killer phenotype of yeasts from olive brines.

The killer properties of yeasts isolated from olive brines were examined in the absence and presence of sodium chloride in concentrations of up to 6% (wt/vol). An apparent enhancement of the killing action as the salt concentration increased, as well as changes in the spectra of activity against selected target strains, was observed in a few strains. Culture filtrates from killer strains grown at different NaCl concentrations (0, 3, or 6% [wt/vol]) were tested against sensitive yeasts cultivated under the same conditions. While the sensitivity of the target strain greatly increased in the presence of salt, no significant effect on toxin production was noticed.

Dose-Response Relationship, Drug↗
PubMed1997

Thyroid hormone controls the expression of insulin-like growth factor I receptor gene at different levels in lung and heart of developing and adult rats.

Thyroid hormone exerts profound effects on the insulin-like growth factors (IGFs)/IGF factor I receptor (IGF-IR) system through its action on the production of IGF-I peptide and IGF-binding proteins. Most of these actions are mediated by the direct control of pituitary GH gene by thyroid hormone. In this work, we have analyzed the possible effect of hypothyroidism on the expression of IGF-IR gene, both in adult and developing animals. Our results show that in the lung and heart, thyroid hormone exerts a negative effect on IGF-IR gene expression in the adult animals and during perinatal life (from day 15 onwards). This negative effect is exerted at different levels. In the heart, this regulation occurs at a pretranslational level, indicated by the fact that parallel changes in the number of membrane IGF-I receptors and IGF-IR transcripts were observed, whereas in lung, no effect of thyroid hormone was noted in the amount of IGF-IR transcripts, suggesting a translational or posttranslational control. GH does not seem to mediate T3 effects on this gene. In contrast, retinoic acid increases the expression of IGF-IR gene at a transcriptional or posttranscriptional level in adult lung and heart. Because the IGFE/ IGF-IR system is depressed in hypothyroid animals, the specific increase in the number of IGF-IRs in the lung and heart of these animals could represent a mechanism to ameliorate the negative effects of hypothyroidism on these important organs.

Aging↗
PubMed1997

Neuronal mitochondrial morphology and transmembrane potential are severely altered by hypothyroidism during rat brain development.

We recently demonstrated that thyroid hormone is an important regulator of mitochondrial gene expression during brain development. To gain further insights into the consequences of this regulation, we have performed functional and structural analysis of brain mitochondria from control and hypothyroid neonatal rats. Flow cytometric analysis showed a significant decrease in the mitochondrial transmembrane potential in hypothyroid animals compared with controls, which was reversed after 48 h, but not after 2 h, of thyroid hormone administration, suggesting that the functional alterations observed are the consequence of changes in mitochondrial gene expression. In addition, band shift studies showed a protein bound to the rat mitochondrial promoter differentially regulated by thyroid state. Electron microscopic analysis of cerebral cortex, striatum, and hippocampus revealed marked differences in the morphology of neuronal mitochondria from control and hypothyroid neonates. Hypothyroid mitochondria presented a decrease in the area of the inner membrane plus cristae in all areas studied, except for the hippocampal CA1 neurons and nonneuronal cell types. The observations reported here provide a basis for the known biochemical action of thyroid hormone on brain development.

Animals↗
PubMed1997

Contact endoscopy of the nasal mucosa.

The possibility of contact endoscopy in the nasal mucosa, using a contact microlaryngoscope is examined. With contact endoscopy it has been possible to visualize in vivo and in situ (60x, 150x) the superficial cell layers of the nasal epithelium, previously stained with methylene blue. Normal mucosa and cases with pathology (chronic rhinitis, nasal polyposis, inverted papilloma, mucormicosis and carcinoma) were assessed with contact endoscopy (50 patients). Squamous epithelium, ciliated epithelium, glandular ostia, mucus secretions, microvascular networks, inflammatory cell infiltrates, tissue inclusions, nuclear abnormalities, and fungal hyphae have been made visible. The potential of contact endoscopy in the nose, the alterations required in the contact endoscope and the intense interdisciplinary work needed are discussed. Evaluation and differentiation of stages of chronic mucosal diseases, nasal polyposis, environmental pathology, allergy, mucocilliary diseases, pharmacotherapy, are some of the entities that will benefit from this technique.

Adolescent↗
PubMed1997

[Transient hyperthyroidism and hyperemesis gravidarum].

Subclinical hyperthyroidism in hyperemesis gravidarum is a well-documented matter in the literature. A case report is present with the main etiologies, clinical manifestations, differential diagnoses, therapeutical guidelines and maternal-infant prognosis are discussed.

Adult↗
PubMed1996

Expression and folding of an interleukin-2-proinsulin fusion protein and its conversion into insulin by a single step enzymatic removal of the C-peptide and the N-terminal fused sequence.

We report the expression in E. coli of a proinsulin fusion protein carrying a modified interleukin-2 N-terminal peptide linked to the N-terminus of proinsulin by a lysine residue. The key aspects investigated were: (a) the expression of the fused IL2-PI gene, (b) the folding efficiency of the insulin precursor when still carrying the N-fused peptide and (c) the selectivity of the enzymatic cleavage reaction with trypsin in order to remove simultaneously the C-peptide and the N-terminal extension. It was found that this construction expresses the chimeric proinsulin at high level (20%) as inclusion bodies; the fused protein was refolded at 100-200 micrograms/ml to yield about 80% of correctly folded proinsulin and then it was converted into insulin by prolonged reaction (5 h) with trypsin and carboxypeptidase B at a low enzyme/substrate rate (1:600). This approach is based on a single enzymatic reaction for the removal of both the N-terminal fused peptide and the C-peptide and avoids the use of toxic cyanogen bromide.

Amino Acid Sequence↗
PubMed1996

Experimental intravitreous cysticercosis.

BACKGROUND: Cysticercosis is one of the parasitic diseases that most frequently affects the eye. The most common and severe manifestations of ocular infection are secondary to posterior segment involvement, which often leads to blindness and atrophy of the eye. The pathogenesis of ocular injury in this disease is poorly understood. The authors have developed an experimental animal model for intravitreous cysticercosis using New Zealand rabbits and Taenia crassiceps cysticerci. METHODS: Twelve rabbits were divided into two groups. Rabbits in group I were inoculated with one living cysticercus in the vitreous cavity. Rabbits in group II received an intramuscular dose of steroids prior to inoculation of parasites. RESULTS: An intense inflammatory reaction, which lead to a severe ocular injury, was observed in rabbits of group I, while rabbits in group II had minimal inflammatory changes. Histopathological studies showed a severe histiocytic infiltrate with generalized retinal damage in group I, and a mild inflammatory infiltrate, limited to the area of direct contact with the parasite in group II. The ocular lesions found in rabbits which did not receive steroids (group I) resembled those found in human ocular cysticercosis. CONCLUSION: These observations indicate that ocular damage in this parasitic disease might be directly related to inflammatory changes produced by the presence of cysticerci. This model appears to be useful for future investigations.

Animals↗
PubMed1996

Ultrasonographic evidence of abnormal lymphatic vessels in young men with adult Wuchereria bancrofti infection in the scrotal area.

PURPOSE: We determined the prevalence and magnitude of dilatation of the lymphatic vessels of the spermatic cord in men infected with Wuchereria bancrofti, which is known major cause of hydrocele in the tropics. MATERIALS AND METHODS: Scrotal ultrasound was performed with a 7.5 MHz, transducer in 78 men from Recife, Brazil (endemic for filariasis) and in 15 from a nonendemic area. RESULTS: Among men from Recife the lymphatic vessels were dilated (1.3 to 15.0 mm., mean 3.8) at the location of the adult worm. Vessel diameter was not associated with hydrocele. CONCLUSIONS: Lymphatic dilation was observed in all men with ultrasonographically detectable W. bancrofti infection, even those who were asymptomatic.

Adolescent↗