Search PubMed⌕ Search

Biomedical subjects

S Castro

Publications and source records attributed to S Castro.

At least 37 records · Page 2Linked to original sources
PubMed1997

Giant intrasacral schwannomas: report of six cases.

Only 4 of the 30 previously reported cases of giant sacral schwannomas have been studied with Magnetic Resonance Imaging (MRI). We are reporting 6 more cases, 5 of which had MRI studies. There were 5 women and 1 man (average age 45 years) with long lasting symptoms consisting of lumbosacral and radicular pain accompanied by urinary disturbances and dysaesthetic sensations in the lower limbs. CT clearly defined sacral bone involvement but poorly demonstrated intraspinal tumour extension which was more evident in MRI studies. MRI also clearly showed the intrapelvic extension of the tumour, its relationship with the neighbouring structures and the dumbbell growth pattern due to tumour extension through sacral foramina which are important data for making a pro-operative diagnosis and surgical planning. Surgical treatment consisted of piecemeal tumour resection through a posterior approach in four cases. Two patients underwent operation through an abdominal transperitoneal approach followed by a sacral laminectomy. Total intracapsular resection was apparently achieved in 5 cases. Through an average follow-up period of 9.2 years and despite a rather conservative approach, the recurrence rate has been very low in our series and only one patient had to be re-operated on for tumour recurrence.

Adolescent↗
PubMed1997

Lipid-laden macrophage infiltration of human adenocarcinoma in vivo associated with taxol and GCSF treatment.

This brief report illustrates the presence of lipid-laden macrophages in proximity to metastatic adenocarcinoma cells within the bone marrow of a patient receiving taxol and GCSF therapy. The pathophysiological mechanism is uncertain. Taxol, which is associated with macrophage function in vitro, may have been responsible for the recruitment of macrophages in this patient. GCSF could have contributed as well; however, GCSF usually has little effect on monocytes and macrophages.

Adenocarcinoma↗
PubMed1997

Remission of hairy cell leukemia without treatment.

A patient is described with hairy cell leukemia, in whom a remission occurred spontaneously or in association with Legionnaires or subsequent HIV infection. Possible pathophysiological mechanisms are reviewed. Currently it is seventeen years since the diagnosis of hairy cell leukemia and fourteen years since the infusion of HIV infected blood. Hairy cell leukemia has yet to return and HIV infection has not progressed to AIDS.

Bone Marrow↗
PubMed1997

[Comparative study of institutionalized and non-institutionalized nonagenarians].

BACKGROUND: The 1992 census showed that 10,470 people over 90 years old lived in Santiago and we do not have information about their general medical status. AIM: To evaluate and compare quality of life and functional status of free living and institutionalized nonagenarians in Santiago. SUBJECTS AND METHODS: During 24 months, 241 people of 90 years or older were interviewed. One hundred twenty seven (96 female) lived in their own homes and 114 (108 female) lived in institutions. The geriatric evaluation scale, validated in previous studies, was used as the assessment instrument. RESULTS: Mean age of subjects was 94 years old (range 90 to 106). Eight percent of subjects were bedridden. No differences in general condition, fecal or urinary continence, nutritional status, blood pressure, cognition, sight and hearing acuity, were observed between free living and institutionalized subjects. Free living elders had a significantly higher number of brothers or offspring and 90% were happy with the place where they lived. CONCLUSIONS: Most nonagenarians in Santiago are in good general medical conditions. Probably, the decision to become institutionalized depends more on lack of family support than on worse medical, functional or mental conditions.

Aged↗
PubMed1996

2,4-Dichlorophenoxyacetic acid affects the attachment of Azospirillum brasilense Cd to maize roots.

2.4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely applied to forage, grain and cereals. We previously determined that 1 mM 2,4-D diminished cell growth and cellular activity of Azospirillum brasilense Cd. The present work was designed to determine the possible effect of this herbicide--at concentrations used on crops--on the attachment of the bacteria to maize roots, since this step is of prime importance for the growth stimulation of the plant obtained with Azospirillum brasilense. In this paper we demonstrate that 2,4-D alters the bacterial adhesion to maize roots.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1996

Characterization of 2,4-dichlorophenoxyacetic acid transport and its relationship with polyamines in Azospirillum brasilense.

We have previously shown that 2,4-dichlorophenoxyacetic acid (2,4-D) inhibits Azospirillum brasilense growth, the synthesis of DNA, RNA and proteins. These toxic effects are prevented when polyamines are added to the culture medium. The purposes of our research were to determine the effects of the herbicide on the number of viable Azospirillum brasilense cells, characterize the 2,4-D transport system and to study the effects of polyamines upon the latter in this microorganism. We found that 2,4-D reduced the number of viable cells and that 2,4-D transport is energy-independent, since it was not affected by metabolic inhibitors. Polyamines did not alter 2,4-D uptake, further supporting the hypothesis that the herbicide most likely produces its toxic effects by interfering with the polyamine metabolism.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1996

Influence of body mass index and slimming habits on menstrual pain and cycle irregularity.

Using a cross-sectional sample of 1147 urban adolescents, aged between 14 and 20 years, the variability of some menstrual cycle indicators was related to weight loss. Nearly 40% of the adolescents tried to lose weight and the results showed that attempting to lose weight is significantly associated with increased prevalence of menstrual irregularity and menstrual pain. This finding is independent of body mass index.

Adolescent↗
PubMed1996

[Pilot experience with the use of an ambulatory geriatric assessment instrument].

BACKGROUND: Ten percent of the Chilean population is over 60 years old and general practitioners need an instrument to assess the degree of disability and multiple ailments of elders. AIM: To develop and use an instrument to assess elders consulting in primary care outpatient clinics. PATIENTS AND METHODS: An instrument to be used by general practitioners, aimed to assess bio-psico-social risk of elders was devised by the Geriatrics Program at the Faculty of Medicine of the Catholic University of Chile. The instrument was used in 100 elders (82 female) aged 71 +/- 8 years old consulting in a primary care outpatient clinic. RESULTS: The instrument took less than 5 minutes to be used. The most frequent risk factors found were living alone in 62% of subjects, falls in the last year in 47%, memory disturbances in 62%, overweight in 76%, visual impairment in 76%, urinary incontinence in 26% and depression in 76%. Thirty percent had difficulties to climb stairs and 4% had no support in case of severe disability. CONCLUSIONS: The applied instrument is fast to apply, easily understood by patients and detects problems associated with old age, that will help to plan primary care health programs.

Aged↗
PubMed1995

Effects of 2,4-dichlorophenoxyacetic acid on polyamine transport and metabolism in Azospirillum brasilense Cd.

We had previously demonstrated that 1 mM 2,4-D inhibited cell growth, nucleic acid synthesis and protein synthesis (at the ribosomal level) of Azospirillum brasilense. These alterations were prevented by the presence of polyamines in the culture medium. On the other hand, polyamines did not affect the 2,4-D uptake. In this paper we demonstrate that 2,4-D alters the metabolism of polyamines and increases their uptake.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1995

Parasitic infection in malnourished school children: effects on behaviour and EEG.

This paper describes a study of 194 children (aged 9-13) from a mountain village in Ecuador who were infected with one or more species of intestinal helminth or protozoan parasite. In addition to parasite load, the assessment consisted of a battery of psychological and neuropsychological tests, an EEG examination, measures of iodine level, presence of goitre and level of nutrition. We found that, in general, parasite infection, as measured at the baseline level, was not associated with cognitive impairment. The intensity of infection with A. lumbricoides, however, was correlated with the level of verbal ability and with inhibition-control aspects of cognitive behaviour. Multivariate analysis with level of nutrition, EEG status and parasite burden showed a consistent main effect of the degree of nutrition on neuropsychological performance, particularly the language, problem solving and inhibition-control dimensions.

Adolescent↗
PubMed1994

Serotype-specific detection of bean common mosaic potyvirus in bean leaf and seed tissue by enzymatic amplification.

An assay involving reverse transcription and polymerase chain reaction (PCR) is described for specific detection of serotypes A and B BCMV isolates in bean leaf and seed tissues. Three oligonucleotide primers designed according to the sequence data available allow, in appropriate combination, serotype-specific detection of BCMV. The sensitivity of the method was sufficient to detect BCMV in as little as 100 fg and 50 pg of infected leaf and seed tissues, respectively.

Base Sequence↗
PubMed1994

Evolutionary relationships among bean common mosaic virus strains and closely related potyviruses.

Bean common mosaic virus (BCMV) consists of a large number of strains with complex and controversial relationships among them and with other potyviruses that infect legumes. In order to elucidate the BCMV taxonomic pattern and its evolutionary implications, a phylogenetic analysis has been carried out. The analysis of the coat protein gene and 3' non-coding region (NCR) sequences recently obtained by us and other currently available potyviral sequences confirms the clustering of viruses comprised in BCMV strains with other closely related potyviruses and reveals the great informative content of 3' NCR, suggesting a more relevant role for this region in phylogenetic analysis.

Amino Acid Sequence↗
PubMed1993

The interaction of 2,4-dichlorophenoxyacetic acid, ribosomes and polyamines in Azospirillum brasilense.

2,4-Dichlorophenoxyacetic acid (2,4-D) is an herbicide used extensively in agriculture. We had previously determined that 1 mM 2,4-D could inhibit cell growth, DNA and protein synthesis of Azospirillum brasilense. The present work was designed to determine if these alterations are a consequence of 2,4-D action on polyamine biosynthesis and if the protein synthesis inhibition is a result of ribosomal impairment. In this paper we demonstrate that 2,4-D alters the metabolism of polyamines and, thus, affects protein synthesis at the ribosomal level.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1993

Performance of the copper T 200 in parous adolescents: are copper IUDs suitable for these women?

The clinical performance of a cohort of 995 parous adolescents, first-time users of the T-Cu 200B was studied and compared with a cohort of paired controls 10 years older, of the same parity. Life-table analysis showed that pregnancy, expulsion rates, as well as removals for bleeding and/or pain were higher in adolescents but within ranges already reported in the literature on this device. Removals for infection were few and not significantly different. Although the clinical performance of the T-Cu 200B in adolescents is not as good as in older women, the performance is similar or better than that reported for other reversible methods in this age group. Our conclusion is that IUDs should not be contraindicated for parous adolescents as long as adequate counseling, screening of risk factors, skillful insertion and follow-up are provided.

Adolescent↗
PubMed1992

Induction of C4-dicarboxylate transport genes by external stimuli in Rhizobium meliloti.

We have characterized two mutants of Rhizobium meliloti L5-30 obtained by random mutagenesis using Mu-lacZ that were defective in transport of C4-dicarboxylic acids. These mutants induced ineffective nodules on alfalfa. Mutations in the two strains appeared to be located in a dctA gene. Levels of dctA gene expression were determined under different environmental conditions using dctA-lacZ fusions, and beta-galactosidase activities increased in response to osmotic stress and also when the cells were incubated in medium low in calcium. The transcriptional induction of the dctA gene by environmental signals was decreased by DNA gyrase inhibitors such as novobiocin and coumermycin.

Aminocoumarins↗