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Biomedical subjects

A Cano

Publications and source records attributed to A Cano.

At least 55 records · Page 3Linked to original sources
PubMed2000

Migraine without aura and migrainous disorder in children; International Headache Society (IHS) and revised IHS criteria.

The widely used criteria of the IHS to define migraine without aura in children are highly specific but show poor sensitivity, with a large percentage of headaches being classified as migrainous disorder (MD). The objective of this study was to assess how many headache patients in a series of children met the diagnostic criteria of the IHS for migraine without aura or MD and to determine the changes required to convert the greatest number of MD into migraine without aura, without affecting classification of the remaining headache types. A prospective study was undertaken of 131 patients under 15 years old referred to our centre for headache. Patients were classified according to the IHS criteria and according to a modification of these criteria consisting of: (1) reduction of minimum time required for classification into migraine without aura from 2 h to 1 h; (2) acceptance of bifrontal location in addition to hemicranial; (3) acceptance of either phonophobia or photophobia as valid criteria instead of requiring presence of both. Using the IHS criteria, 51 (39%) children were diagnosed as having migraine without aura and 26 (20%) as having MD. According to our revised IHS criteria, 68 (52%) were diagnosed as migraine without aura and nine (7%) as MD. When the three modified criteria were applied, three tension headaches and one unclassifiable headache changed category. When only reduced duration and bifrontal location were applied, none of the headaches other than MD changed category. Application of two modifications to the IHS criteria--reduction in duration of headache to 1 h and acceptance of bifrontal location--increased sensitivity without reducing specificity in classifying migraine without aura in children.

Adolescent↗
PubMed2000

A method to measure antioxidant activity in organic media: application to lipophilic vitamins.

The 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) radical (ABTS(.+)) can be generated by the enzymatic system formed by hydrogen peroxide and horseradish peroxidase in an organic medium. The ABTS radical is easily generated in acidified ethanol medium in about 100 s with a stability of 1.7 x 10(-3) (-deltaabs/min) monitored at 730 nm. Other organic solvents, such as methanol or acetone, have lower radical generation times but the radical is less stable. The addition of Trolox or a lipophilic antioxidant such as alpha-tocopherol or beta-carotene produces a decrease in absorbance that can be used to estimate antioxidant capacity. Using a spectrophotometric end-point method and microplate-reader equipment, we have developed a method that estimates the antioxidant activity of different lipophilic vitamins. The use of Trolox as an antioxidant standard led to a limit of detection of 0.08 nmoles and limit of quantitation of 0.28 nmoles, while similar values were obtained for alpha-tocopherol and beta-carotene. The relative antioxidant activity values obtained by different antioxidants showed that alpha-tocopherol has a similar antioxidant potential to Trolox and that beta-carotene has 2.6 times the antioxidant potential of Trolox. In our opinion, this method can be useful for estimating the antioxidant activity in lipophilic samples and as a complement to other methods that measure antioxidant activity in aqueous media.

Antioxidants↗
PubMed2000

[HERS study disturbs hormonal replacement therapy].

Cardiovascular protection of hormonal replacement therapy was considered a fact. The effects of estrogens on lipid levels and vascular health gave biological support to estrogen cardioprotection. The recently published HERS study showing no protective effects of estrogen and progesterone replacement therapy on the risk of myocardial infarction or coronary deaths is provoking perplexity. These surprising results may have several causes such as the use of progesterone, the associated use of cardioprotective agents or the short observation period. However, the study results scope is restricted to secondary prevention. These cannot be extrapolated to frequent conditions of postmenopausal women such as primary prevention or sequential schemes. Likewise, this investigation underscores the importance of a critical and continued evaluation of apparently well established therapeutic approaches.

Estrogen Replacement Therapy↗
PubMed2000

Infidelity and separations precipitate major depressive episodes and symptoms of nonspecific depression and anxiety.

This study examined whether humiliating marital events (HMEs; husbands' infidelity, threats of marital dissolution) precipitated Major Depressive Episodes (MDEs) when controlling for marital discord. Participants were 25 women who recently experienced an HME and 25 control women who did not experience an HME. Both groups reported similar levels of marital discord. Results indicated that HME participants were 6 times more likely to be diagnosed with an MDE than control participants. These results remained even after controlling for family and lifetime histories of depression. HME participants also reported significantly more symptoms of nonspecific depression and anxiety than control participants. However, HME and control participants did not report significantly different numbers of anhedonic depression and anxious arousal symptoms. The research and clinical implications of these findings are discussed.

Adult↗
PubMed1999

H-Ras activation promotes cytoplasmic accumulation and phosphoinositide 3-OH kinase association of beta-catenin in epidermal keratinocytes.

The mechanisms underlying downregulation of the cadherin/catenin complexes and beta-catenin signaling during tumor progression are not fully understood. We have analyzed the effect of oncogenic H-Ras on E-cadherin/catenin complex formation/stabilization and beta-catenin distribution in epidermal keratinocytes. Microinjection or stable expression of V12Ras into keratinocytes promotes the loss of E-cadherin and alpha-catenin and relocalization of beta-catenin to the cytoplasm and nucleus. Moreover, these effects are dependent on PI3K (phosphoinositide 3-OH kinase) activity. Interestingly, a strong association of p85alpha and p110alpha subunits of PI3K with beta-catenin is induced in V12Ras-expressing keratinocytes, and in vitro binding assays show a direct interaction between beta-catenin and p85alpha. Overexpression of either V12Ras or constitutively active p110alpha induces metabolic stabilization of beta-catenin and promotes its accumulation in cytoplasmic and nuclear pools. In addition, the interaction of beta-catenin with the adenomatous polyposis coli protein is blocked in V12Ras and p110alpha transformants though no changes in glycogen synthase kinase 3 beta activity could be detected. Nevertheless, in V12Ras transformants the in vivo phosphorylation of beta-catenin in Ser residues is strongly decreased. These results indicate that H-Ras activation induces the relocalization and cytoplasmic stabilization of beta-catenin by a mechanism involving its interaction with PI3K.

Adenomatous Polyposis Coli Protein↗
PubMed1999

Regulation of E-cadherin gene expression during tumor progression: the role of a new Ets-binding site and the E-pal element.

A new regulatory region (-108 to -86), named CE, containing potential CRE- and Ets-binding sites has been identified in the murine E-cadherin promoter. The Ets-binding site (at -97 position) negatively modulates the activity of the E-cadherin promoter in expressing keratinocyte cell lines and was responsible for the specific retarded complexes obtained with the CE region. Analysis of the methylation status of the endogenous E-cadherin promoter indicated that silencing of E-cadherin expression in malignant keratinocytes cannot be explained by hypermethylation mechanisms. Furthermore, treatment with 5'-aza-2'-deoxycytidine was unable to induce the expression of E-cadherin in deficient keratinocytes. However, in vivo footprinting analysis of the endogenous E-cadherin promoter showed a very distinct pattern in expressing and nonexpressing keratinocytes. Extensive interactions in the previously postulated proximal regulatory elements and in the CE region were detected in expressing cells, while only some nucleotides of the E-pal element and of the CE region were protected in nonexpressing keratinocytes. These results indicate a complex regulation of the mouse E-cadherin promoter and support a model where the combination of positive (CCAAT-box and GC-rich region) and negative (E-pal element and CE region) cis-acting elements contribute to the final level of E-cadherin gene expression. In addition, our results show that downregulation of E-cadherin expression in transformed epidermal keratinocytes is mainly exerted through the interaction of repressor factor(s) with the E-pal element and to the lack of interaction of positive acting factors with the proximal regions.

3T3 Cells↗
PubMed1999

The hairless gene of the mouse: relationship of phenotypic effects with expression profile and genotype.

Various mutations of the hairless (hr) gene of mice result in hair loss and other integument defects. To examine the role of the hr gene in mouse development, the expression profile of hr has been determined by in situ hybridisation and correlated to the nature of genetic changes and morphological abnormalities in different mutant animals. Four variant alleles have been characterised at the molecular level. hr/hr mice produce reduced, but significant, levels of hr mRNA whereas other alleles contain mutations which would be expected to preclude the synthesis of functional product, demonstrating a correlation between allelic variation at the hr locus and phenotypic severity. hr expression was shown to be widespread and temporally regulated. It was identified in novel tissues such as cartilage, developing tooth, inner ear, retina, and colon as well as in skin and brain. Analysis of mice homozygous for the rhino allele of hairless revealed that, although no morphological defects were detectable in many tissues normally expressing hr, previously undescribed abnormalities were present in several tissues including inner ear, retina, and colon. These findings indicate that the hairless gene product plays a wider role in development than previously suspected. Dev Dyn 1999;216:113-126.

Animals↗
PubMed1999

Characterization of cerebrospinal fluid antibody specificities in neurocysticercosis using phage display peptide library.

To identify epitopes for antibodies present in cerebrospinal fluid (CSF) samples from two patients with confirmed neurocysticercosis, we used a phage peptide library that displayed random dodecapeptides as a fusion to the minor coat protein (pIII) of phage M13. To increase the specificity of selection, plates coated with anti-human Fc antibody were used in five rounds of biopanning. The DNA inserts of 30 selected clones were determined and the deduced amino acid sequences were analyzed. Sequence similarities between affinity-selected clones and three known T. solium and T. crassiceps proteins were encountered. Two phage clones have been shown to react in enzyme-linked immunosorbent assay with CSF samples from other patients with neurocysticercosis, and no reaction was observed with CSF samples from patients with other neurological disorders used as negative controls. Our results suggest that affinity selection of peptides from phage libraries using CSF samples from patients is an attractive tool for the development of novel reagents for a simple and sensitive immunodiagnostic test and for understanding the molecular mechanisms participating in the pathogenesis of neurocysticercosis.

Amino Acid Sequence↗
PubMed1999

Two-year prospective, randomized trial comparing an innovative twice-a-week progestin regimen with a continuous combined regimen as postmenopausal hormone therapy.

OBJECTIVE: To compare compliance, symptom control, bleeding patterns, endometrial response, and lipid changes in postmenopausal women treated with transdermal E2 and a regimen of either intermittent or continuous dosing of progestin. DESIGN: Randomized, prospective study. SETTING: Menopausal Outpatient Clinic at an academic tertiary care hospital. PATIENT(S): One hundred women who had reached menopause naturally and had been amenorrheic for at least 1 year. Fifty women were randomly assigned to receive each regimen. INTERVENTION(S): All patients received 50-microg E2 patches and medroxyprogesterone acetate, either 5 mg twice per week or 2.5 mg daily. The bleeding pattern was registered in diary cards. Endometrial status was assessed by vaginal ultrasound and endometrial biopsy. Lipid levels were measured by ELISA. MAIN OUTCOME MEASURE(S): The number of patients who dropped out of the study and the number of days each patient reported spotting or bleeding were recorded. Endometrial thickness was measured and histologic examination of the endometrial tissue was performed. Plasma levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were measured. RESULT(S): Fourteen women dropped out of the intermittent dosing group and 13 dropped out of the continuous dosing group. Irregular spotting or bleeding occurred at a similar rate in both groups. Biopsies performed at the end of the study showed adequate endometrial stabilization in both groups. No significant changes in lipid levels were detected with either regimen. CONCLUSION(S): Both regimens were similarly effective. The high rate of atrophic endometria suggests the possibility of further reduction of the progestin dose.

Administration, Cutaneous↗
PubMed1999

Effect of menopause and different combined estradiol-progestin regimens on basal and growth hormone-releasing hormone-stimulated serum growth hormone, insulin-like growth factor-1, insulin-like growth factor binding protein (IGFBP)-1, and IGFBP-3 levels.

OBJECTIVE: To determine the effects of menopause and three different formulations of E2 plus medroxyprogesterone acetate on serum concentrations of basal and growth hormone-releasing hormone (GHRH)-stimulated growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein (IGFBP)-1, IGFBP-3, insulin, and C peptide. DESIGN: Prospective, controlled trial. SETTING: Menopausal outpatient clinic at an academic tertiary care hospital. PATIENT(S): Nineteen postmenopausal women with different menopausal ages. Seventeen premenopausal women were included as controls. INTERVENTION(S): Oral estrogen (E2 valerate, 2 mg/d) or transdermal estrogen (50-microg or 100-microg E2 patch) was administered for 8 weeks. Medroxyprogesterone acetate (5 mg/d) was administered during weeks 3, 4, 7, and 8 of each protocol. Blood samples were collected before treatment and after the completion of each protocol from postmenopausal women, and on cycle days 6-8 from premenopausal women. MAIN OUTCOME MEASURE(S): Levels of GH, IGF-1, IGFBP-1, IGFBP-3, insulin, and C peptide. RESULT(S): Basal GH levels were negatively correlated with age in premenopausal women but not in postmenopausal women. The area under the GHRH-induced GH curve decreased in older postmenopausal women after the oral estrogen protocol. Levels of IGF-1 diminished after the oral E2 protocol in postmenopausal women. CONCLUSION(S): The administration of oral, but not transdermal, E2 plus medroxyprogesterone acetate at the usual clinical doses used in postmenopausal women decreased IGF-1 levels and the response of GH to GHRH in older women. No substantial changes were detected in IGFBP-1, IGFBP-3, insulin, or C peptide levels.

Adult↗
PubMed1999

Analysis of indirect signs of microprolactinoma at MR imaging.

OBJECTIVE: To evaluate the diagnostic reliability/value of microprolactinoma indirect signs at MRI. METHODS AND MATERIAL: A prospective study was carried out over 3 years on 26 women with microprolactinoma (MiP group) and 106 healthy female volunteers as a control group. Size, glandular morphology, pituitary stalk inclination and sellar bony floor erosion were measured and a comparative statistical analysis between both groups was performed. RESULTS: Patients from the MiP group showed a significantly bigger glandular size than women in the control group, although the glandular morphology did not present significant differences between both groups. Only 5% of normal glands measured over 7.5 mm in height and none of them reached 9 mm, while up to 42.3% of the MiP group scored over 7.5 mm and 19.2% over 9 mm. Mean stalk inclination for the MiP group was 4.6 +/- 3.1 degrees and 3.5 +/- 2.7 degrees for the control group with no significant differences. Five microprolactinomas were located on the glandular midline, 11 on the left side and ten on the right side. No relationship between the microadenoma location inside the gland and stalk inclination was found. From 21 microprolactinomas with eccentric location, 17 coincided with the sellar floor excavation; eccentric excavation presented significant differences between both groups, but not the central excavation. CONCLUSION: From all indirect sings of microprolactinoma analyzed in this study, only a gland height over 9 mm, and an eccentric sellar excavation of at least 3 mm are reliable signs to support its diagnosis.

Adolescent↗
PubMed1999

Opioid peptide systems following a subconvulsant dose of pentylenetetrazol in rats.

The development of epilepsy and a progressive increase in susceptibility to seizures may involve changes in inhibitory and excitatory systems from the beginning of the process. The present study was focused to analyze the opioid peptide changes induced by a chemical sub-convulsant stimulation. Experiments were carried out to determine opioid peptide release, mu receptor binding and proenkephalin expression in rat brain, as well as nociceptive responses, following the administration of a sub-convulsant dose of pentylenetetrazol (PTZ) (30 mg/kg, i.p.). Membrane binding experiments revealed reduced number of mu binding sites (Bmax) in cortex and amygdala, but not in striatum and hippocampus, an effect that was evident only 24 h, but not 28 days, after PTZ treatment. In situ hybridization experiments suggested a significant enhancement of proenkephalin mRNA expression in specific brain regions 24 h after PTZ treatment. Microdialysis combined with a universal opioid peptide radioimmunoassay revealed extracellular opioid peptide levels to be elevated in the amygdala (137%) 90 min after PTZ administration. Evaluation of nociceptive responses using the Randall-Selitto test showed an analgesic effect short term (30-90 min) after PTZ injection. Collectively, these data provide evidence for a significant activation of opioid peptide systems as a consequence of the administration of a sub-convulsant dose of PTZ. These neurochemical changes may play an important role in the progression of epileptogenesis.

Animals↗
PubMed1999

Effect of intracellular Ca2+ chelation with the acetoxymethyl ester-derived form of bis(o-aminophenoxy)ethane-N,N,N,N',N'-tetraacetic acid on meiotic division and chromosomal segregation in mouse oocytes.

PURPOSE: Our purpose was to ascertain the effect of intracellular Ca2+ chelation on the chromosomal distribution and segregation of mouse oocytes during maturation in vitro. METHODS: Germinal vesicle oocytes were loaded with the acetoxymethyl ester-derived form of bis(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM). Chromosomal distribution and segregation of control and BAPTA-AM-treated metaphase II (MII) oocytes were evaluated at 16 hr, and intracellular ATP content at 0, 1, and 16 hr after BAPTA-AM loading. RESULTS: BAPTA-AM treatment decreased (P < or = 0.05) the potential for in vitro maturation, increased (P < or = 0.0001) the percentage of oocytes displaying an abnormal distribution of metaphase II chromosomes in the meiosis II spindle and aneuploidy, and decreased (P < or = 0.005) the ATP content at 0, 1, and 16 hr of culture compared to the control groups. CONCLUSIONS: These findings raise some concern about any other condition/drug that may directly or indirectly decrease the intracellular Ca2+ concentration in human oocytes.

Adenosine Triphosphate↗
PubMed1999

Diagnosis of hepatopulmonary syndrome with contrast transesophageal echocardiography: advantages over contrast transthoracic echocardiography.

The aim of this study was to study the prevalence of hepatopulmonary syndrome (HPS) in cirrhotic patients, comparing the results obtained using contrast transthoracic echocardiography (CTTE) and contrast transesophageal echocardiography (CTEE) in the demonstration and grading of pulmonary vasodilatation (PV). We also analyzed the correlation between gas-exchange abnormalities and PV when it was demonstrated with both techniques. The prevalence of PV and HPS with CTEE in the 88 cirrhotic patients was 28% and 22%, respectively, and with CTEE, 42% (P < 0.05) (middle PV: 35% and significant PV: 7%) and 30% (P < 0.05), respectively. Fifty-six percent of patients diagnosed with PV and with CTTE presented with hypoxemia as did 49% using CTEE (83% of patients with significant PV had hypoxaemia). PaCO2 and diffusing capacity of CO were significantly more decreased in patients with PV than in patients without PV when CTEE was employed. We conclude that CTEE is superior to CTTE in the diagnosis and grading of PV in the diagnosis of HPS in cirrhotic patients, being more sensitive and presenting a better correlation with gas-exchange abnormalities. Given its high sensitivity, CTEE should be carried out in all patients with suspicion of HPS and normal or uncertain CTTE.

Aged↗