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Biomedical subjects

H Silva

Publications and source records attributed to H Silva.

At least 19 recordsLinked to original sources
PubMed2001

[Subclinical thyroid disease in institutionalised healthy geriatric population].

BACKGROUND: Our aim was to determine the prevalence of subclinical thyroid disease in a healthy institutionalised geriatric population. PATIENTS AND METHOD: We determined TSH, free T4 and antithyroid antibodies from 242 healthy elderly subjects living in Andalusian public nursing homes. RESULTS: Subclinical hypothyroidism was detected in 3.71% of cases; clinical hypothyroidism in 1.65%; subclinical hyperthyroidism in 0.82%,and autoimmune disease in 10.33%. CONCLUSIONS: There is a high rate of clinically undetected thyroid dysfunction among the healthy institutionalised geriatric population. Therefore, a hormonal screening may be justified in this population.

Aged↗
PubMed2001

[Clinical and psychometric diagnosis of depression in patients in general medicine].

BACKGROUND: The Hamilton scale, applied by an external evaluator and the self rating Beck inventory for depression, can give discrepant results in psychiatric patients with depression. AIM: To compare depression scores obtained with the Hamilton scale and the Beck inventory in general medical patients. PATIENTS AND METHODS: Patients attending an outpatient clinic of a University Hospital were studied. Clinical psychiatric diagnoses were based on DSM-III. Hamilton scale was applied to 100 patients and 80 answered the Beck depression inventory. RESULTS: Patients with major depression obtained the higher scores with both scales. However, Beck inventory had false positive and false negative results. Moreover, some patients overstated their depressive symptoms. CONCLUSIONS: Self assessment of depression can be distorted by anxiety and somatic symptoms.

Adult↗
PubMed2000

Nitric oxide and salicylic acid signaling in plant defense.

Salicylic acid (SA) plays a critical signaling role in the activation of plant defense responses after pathogen attack. We have identified several potential components of the SA signaling pathway, including (i) the H(2)O(2)-scavenging enzymes catalase and ascorbate peroxidase, (ii) a high affinity SA-binding protein (SABP2), (iii) a SA-inducible protein kinase (SIPK), (iv) NPR1, an ankyrin repeat-containing protein that exhibits limited homology to IkappaBalpha and is required for SA signaling, and (v) members of the TGA/OBF family of bZIP transcription factors. These bZIP factors physically interact with NPR1 and bind the SA-responsive element in promoters of several defense genes, such as the pathogenesis-related 1 gene (PR-1). Recent studies have demonstrated that nitric oxide (NO) is another signal that activates defense responses after pathogen attack. NO has been shown to play a critical role in the activation of innate immune and inflammatory responses in animals. Increases in NO synthase (NOS)-like activity occurred in resistant but not susceptible tobacco after infection with tobacco mosaic virus. Here we demonstrate that this increase in activity participates in PR-1 gene induction. Two signaling molecules, cGMP and cyclic ADP ribose (cADPR), which function downstream of NO in animals, also appear to mediate plant defense gene activation (e.g., PR-1). Additionally, NO may activate PR-1 expression via an NO-dependent, cADPR-independent pathway. Several targets of NO in animals, including guanylate cyclase, aconitase, and mitogen-activated protein kinases (e.g., SIPK), are also modulated by NO in plants. Thus, at least portions of NO signaling pathways appear to be shared between plants and animals.

Adenosine Diphosphate Ribose↗
PubMed2000

NPR1 differentially interacts with members of the TGA/OBF family of transcription factors that bind an element of the PR-1 gene required for induction by salicylic acid.

NPR1 is a critical component of the salicylic acid (SA)-mediated signal transduction pathway leading to the induction of defense genes, such as the pathogenesis-related (PR)-1 gene, and enhanced disease resistance. Using a yeast two-hybrid screen, we identified several NPR1-interacting proteins (NIPs). Two of these NIPs are members of the TGA/OBF family of basic leucine zipper (bZIP) transcription factors; this family has been implicated in the activation of SA-responsive genes, including PR-1. Six TGA family members were tested and shown to differentially interact with NPR1: TGA2 and TGA3 showed strong affinity for NPR1; TGA5 and TGA6 exhibited weaker affinity; and TGA1 and TGA4 displayed little or no detectable interaction with NPR1, respectively. Interestingly, the amino-termini of these factors were found to decrease their stability in yeast and differentially affect their apparent affinity toward NPR1. The interacting regions on NPR1 and the TGA factors were also defined. Each of four point mutations in NPR1 that disrupt SA signaling in Arabidopsis completely blocked interaction of NPR1 with TGA2 and TGA3. TGA2 and TGA3 were also found to bind the SA-responsive element of the Arabidopsis PR-1 promoter. These results directly link NPR1 to SA-induced PR-1 expression through members of the TGA family of transcription factors.

Amino Acid Sequence↗
PubMed2000

Treatment and recovery rate in depression: a critical analysis.

The objective of this study was to evaluate the frequency and consequences of the presence of residual symptoms in patients treated for major depression. The literature specifically focused on recovery and residual symptomatology of depression was reviewed. Thirty per cent or more of treated patients present residual symptoms. These symptoms appear to be associated with a higher frequency and larger number of relapses and equally affect the outcome of depression in different age groups. They also seem to have a major impact on work and psychosocial functioning because of cognitive dysfunction and a reduction in social interaction affecting patients' quality of life. We found that there is scant literature on residual symptoms contrasting with the profuse reports on single or multiple antidepressant drug trials. Studies focusing on this important issue in the treatment of depression are needed.

Antidepressive Agents↗
PubMed1999

High-performance liquid chromatographic assay with a simple extraction procedure for sensitive quantification of mycophenolic acid in rat and human plasma.

We describe a novel sensitive and simplified gradient HPLC assay for quantification of the immunosuppressant mycophenolic acid (MPA) in rat and human plasma. In contrast to previously reported MPA assays, our method used a single step extraction comprising addition of acetonitrile, which contained phenolphthalein glucoronic acid as internal standard, for protein precipitation. Linearity: 0.1-100 microg/ml (r2>0.999), mean recoveries: MPA 98.0%, internal standard 105.2%, mean intra-day precision: 4.3%, mean day-to-day precision: 4.3%, mean day-to-day accuracy: -1.5%. Sensitivity was sufficient to allow for quantification of mycophenolic acid in as little as 50 microl plasma.

Animals↗
PubMed1999

Characterization of a new Arabidopsis mutant exhibiting enhanced disease resistance.

In many plant-pathogen interactions, resistance is associated with the synthesis and accumulation of salicylic acid (SA) and pathogenesis-related (PR) proteins. At least two general classes of mutants with altered resistance to pathogen attack have been identified in Arabidopsis. One class exhibits increased susceptibility to pathogen infection; the other class exhibits enhanced resistance to pathogens. In an attempt to identify mutations in resistance-associated loci, we screened a population of T-DNA tagged Arabidopsis thaliana ecotype Wassilewskija (Ws) for mutants showing constitutive expression of the PR-1 gene (cep). A mutant was isolated and shown to constitutively express PR-1, PR-2, and PR-5 genes. This constitutive phenotype segregated as a single recessive trait in the Ws genetic background. The mutant also had elevated levels of SA, which are responsible for the cep phenotype. The cep mutant spontaneously formed hypersensitive response (HR)-like lesions on the leaves and cotyledons and also exhibited enhanced resistance to virulent bacterial and fungal pathogens. Genetic analyses of segregating progeny from outcrosses to other ecotypes unexpectedly revealed that alterations in more than one gene condition the constitutive expression of PR genes in the original mutant. One of the mutations, designated cpr20, maps to the lower arm of chromosome 4 and is required for the cep phenotype. Another mutation, which has been termed cpr21, maps to chromosome 1 and is often, but not always, associated with this phenotype. The recessive nature of the cep trait suggests that the CPR20 and CPR21 proteins may act as negative regulators in the disease resistance signal transduction pathway.

Arabidopsis↗
PubMed1999

The growth hormone (GH)-releasing hormone-GH-insulin-like growth factor-1 axis in patients with fibromyalgia syndrome.

Fibromyalgia (FM) is a painful syndrome of nonarticular origin, characterized by fatigue and widespread musculoskeletal pain, tiredness, and sleep disturbances, without any other objective findings on examination. Interestingly, some of the clinical features of FM resemble the ones described in the adult GH-deficiency syndrome. Furthermore, insulin-like growth factor (IGF)-1 levels are frequently reduced in patients with FM. To gain further insight into the mechanisms leading to dysregulation of the GH-IGF-1 axis in these patients, we assessed 24-h spontaneous GH secretion, GH responses to GHRH, and IGF-1 and IGF binding protein (BP)-3 levels before and after 4 days treatment with human (h)GH. We found that, in comparison with controls, patients with FM exhibited a marked decrease in spontaneous GH secretion as assessed by mean GH secretion (2.5 +/- 0.4 microg/L in controls vs. 1.2 +/- 0.1 microg/L in FM, P < 0.05), pulse height (4.7 +/- 0.8 microg/L in controls vs. 2.5 +/- 0.3 microg/L in FM, P < 0.05), and pulse area (4.7 +/- 1 min/mg x L in controls vs. 2.3 +/- 0.3 min/mg x L in FM, P < 0.05). In contrast, GH responses to GHRH (100 microg, i.v.) were similar in controls (mean peak, 13.5 +/- 2.5 microg/L) and in patients with FM (12.2 +/- 3 microg/L). Finally, treatment with hGH (2 IU, s.c. daily), over 4 days, led to a clear-cut increase in plasma IGF-1 and IGFBP-3 levels in patients with FM. In conclusion, our data show that patients with FM exhibited a marked decrease in spontaneous GH secretion, but normal pituitary responsiveness to exogenously administered GHRH, thus suggesting the existence of an alteration at the hypothalamic level in the neuroendocrine control of GH in these patients. Furthermore, our finding of increased IGF-1 and IGFBP-3 levels after GH treatment, over 4 days, opens up the possibility of testing the therapeutic potential of hGH in patients with FM.

Adult↗
PubMed1998

Effects of pimozide on the psychopathology of delusional disorder.

1. The effects of pimozide on the psychopathology of delusional disorder were studied. 2. After six weeks, pimozide (2-12 mg/day) administration had no effect on the Brief Psychiatric Rating Scale, or in the psychological, social and occupational functioning, as measured by the Global Assessment of Functioning Scale. 3. When the different dimensions of the delusional experience were looked upon, no modifications were observed in any of them after six weeks of pimozide treatment. 4. These data failed to support the therapeutic role of pimozide in the treatment of delusional disorder and may suggest, when compared to other disorders with prominent delusions such as schizophrenia, a different neurobiology for the illness.

Adult↗
PubMed1998

Engineering disease and pest resistance in plants.

Improvements in transformation techniques and the isolation of many genes whose transcripts or protein products either have antimicrobial or insecticidal activity or are involved in the synthesis of products with such activities have provided valuable tools for engineering resistance in plants. Future exploitation of this technology should provide an environmentally friendly alternative to traditional disease and pest control measures.

Anti-Infective Agents↗
PubMed1998

Conception after iodine-131 therapy for differentiated thyroid cancer.

We reviewed the medical history of 26 women with differentiated thyroid cancer who became pregnant after receiving therapeutic doses of radioactive iodine (131I) in order to document the possibility of a greater risk for disorders in these pregnancies. There were a total of 39 pregnancies, 6 of which occurred during the first year after therapy. In 3 cases the following anomalies were encountered: a male suffering Trisomy 18 (Edward's syndrome), a female with constitutional aplastic anemia, and a male with a congenital hip dysplasia. Of the 33 pregnancies that occurred after the first year post-therapy, there were 2 spontaneous abortions and a male effected by ureteral stenosis. Based on these data, although it cannot be confirmed that these congenital disorders are due to the 131I therapy, we recommend that pregnancy be avoided for the first year after therapy.

Abortion, Spontaneous↗
PubMed1998

[Acquired characteristics of porphyria cutanea tarda in patients infected with hepatitis C virus].

BACKGROUND: Porphyria cutanea tarda (PCT) is due to a partial defect of hepatic uroporphyrinogen decarboxylase (URO-D). In the hereditary form, both hepatic and erythrocytic enzymes are altered, whereas in the acquired form, only the hepatic enzyme fails. There is a high prevalence of hepatitis C virus infection in patients with PCT, specially in those without family history of the disease. AIM: To study erythrocytic URO-D activity in order to find out whether hepatitis C virus infection is associated to the acquired form of PCT or unveils an inactive hereditary form. PATIENTS AND METHODS: URO-D activity was measured in red blood cells of normal controls, hepatitis C virus carriers without symptoms of PCT and patients with PCT, with and without family history of the disease, with and without anti hepatitis C virus antibodies. RESULTS: URO-D activity was similar in normal controls, patients with chronic liver disease associated to hepatitis C virus, and in patients with PCT without family history of the disease with and without hepatitis C virus antibodies. URO-D activity was lower in patients with PCT and family history of the disease, with and without hepatitis C virus antibodies. CONCLUSIONS: PCT in patients with hepatitis C virus infection is due to an acquired alteration of hepatic URO-D. Hepatitis C virus does not modify erythrocytic URO-D.

Adult↗
PubMed1997

[Trichotillomania. Clinical case].

Trichotillomania is characterized by recurrent pulling out of one's hair for pleasure, gratification, or relief of tension that results in noticeable hair loss. We report the case of a 31 years old woman with a 20 years clinical history of trichotillomania who responded favourably to fluoxetine, a serotonin selective reuptake inhibitor.

Adult↗
PubMed1995

Induction, modification, and transduction of the salicylic acid signal in plant defense responses.

Studies in our laboratory as well as others strongly suggest that salicylic acid (SA) plays an important signaling role in plant defense against pathogens. We have found that increases in endogenous SA levels correlates with both resistance of tobacco to infection with tobacco mosaic virus and induction of defense-related genes such as that encoding pathogenesis-related protein 1 (PR-1). Some of this newly synthesized SA was conjugated to glucose to form SA beta-glucoside. A cell wall-associated beta-glucosidase activity that releases SA from this glucoside has been identified, suggesting that SA beta-glucoside serves as an inactive storage form of SA. By purifying a soluble SA-binding protein and isolating its encoding cDNA from tobacco, we have been able to further characterize the mechanism of SA signaling. This protein is a catalase, and binding of SA and its biologically active analogues inhibited catalase's ability to convert H2O2 to O2 and H2O. The resulting elevated levels of cellular H2O2 appeared to induce PR-1 gene expression, perhaps by acting as a second messenger. Additionally, transgenic tobacco expressing an antisense copy of the catalase gene and exhibiting depressed levels of catalase also showed constitutive expression of PR-1 genes. To further dissect the SA signaling pathway, we have tested several abiotic inducers of PR gene expression and disease resistance for their ability to stimulate SA production. Levels of SA and its glucoside rose following application of all of the inducers except 2,6-dichloroisonicotinic acid. 2,6-Dichloroisonicotinic acid was found to bind catalase directly and inhibit its enzymatic activity. Thus, it appears that many compounds that induce PR gene expression and disease resistance in plants inactivate catalases directly or indirectly.

Journal Article↗
PubMed1995

A new technique for laparoscopic repair of hypertrophic pyloric stenosis.

Since 1987, pyloric traumamyoplasty, a technique for the resolution of hypertrophic pyloric stenosis, has been used in 111 patients. Continuous prensile force is applied with Babcock intestinal clamps, with consequent rupture of the muscular layer, without disruption of the mucosa. Because this is a simple procedure that requires introduction of only one noncutting instrument, it has now been applied laparoscopically in 17 patients. Twelve were under 30 days of age; seven weighed less than 3.5 kg. The hospital stay averaged 1.8 days, and the average surgical time was less than 30 minutes. Only two trocar incisions were made in each case--one for the laparoscope video camera and lamp, the other for a modified Babcock clamp. There were no deaths and no complications related to the pyloric repair procedure. The authors conclude that laparoscopic pyloric traumamyoplasty is an attractive alternative for the management of hypertrophic pyloric stenosis.

Female↗
PubMed1995

Effects of D-amphetamine administration on the release of endogenous excitatory amino acids in the rat nucleus accumbens.

1. The effects of acute D-amphetamine administration to rats on the release of endogenous excitatory amino acids from nucleus accumbens slices were studied. 2. D-amphetamine (5 mg/kg and 10 mg/kg; i.p.) significantly increased the spontaneous release of aspartate and glutamate from nucleus accumbens slices. 3. In contrast, D-amphetamine either produced no change or rather decreased K+ (40 mM)-evoked and N-methyl-D-aspartate (100 microM)-evoked release of aspartate and glutamate from the slices, respectively. 4. When D-amphetamine treated rats were pretreated with haloperidol, the effects of D-amphetamine on the spontaneous release of excitatory amino acids were not produced, whereas its effects on N-methyl-D-aspartate-evoked release remained unchanged. 5. These data suggest that amphetamine produces changes in excitatory amino acid-mediated transmission in the nucleus accumbens, that may play a role in amphetamine-induced behavioral or psychotomimetic effects.

Amphetamine↗
PubMed1995

[Delusional disorders with delirium of somatic type].

The delusional disturbance is characterized by the presence of persistent delusions that are not bizarre, which cannot be attributed to schizophrenia, mood state disorders, substance abuse or organic brain disease. We report a 37 years old male that presented the disease during the last seven years and had very little response to a two months course of pimozide, a neuroleptic whose effectiveness in this disease has been suggested.

Adult↗