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Biomedical subjects

I Rivas

Publications and source records attributed to I Rivas.

10 recordsLinked to original sources
PubMed2005

Functional analysis of the early chlorosis factor gene.

Chlorosis is one of the symptoms of bacterial spot disease caused by Xanthomonas campestris pv. vesicatoria, which induces chlorosis before any other symptoms appear on tomato. We report characterization of a 2.1-kb gene called early chlorosis factor (ecf). The gene ecf encodes a hydrophobic protein with similarity to four other proteins in plant pathogens, including HolPsyAE, and uncharacterized gene products from X. campestris pv. campestris and X. axonopodis pv. citri, and, at the tertiary structure level, to colicin Ia from Escherichia coli. We demonstrate that the associated phenotype is hrp dependent, and that the ecf gene product appears to be translocated to host cells. The gene ecf has no impact on electrolyte leakage or on bacterial growth in planta in response to infection. Concentrated culture filtrates do not produce chlorosis. Study of its role in Xanthomonas spp.-tomato interactions will forward our understanding of symptom production by plant pathogens and allows further investigation into the mechanisms of bacterial virulence and production of symptoms.

Amino Acid Sequence↗
PubMed1997

Fatal Listeria meningitis, endocarditis and pericarditis in a patient with haemochromatosis.

A 65-year-old man with primary haemochromatosis was admitted because of fever and confusion. He was found to have bacteraemia and meningitis due to Listeria monocytogenes. Treatment with ampicillin plus tobramycin was instituted, and despite an initial improvement, the patient experienced an unfavourable course and died. At postmortem examination, tricuspid valve endocarditis and purulent pericarditis with tamponade were detected. Listeria monocytogenes grew in the culture of the pericardial fluid. Documentation of Listeria monocytogenes pericarditis is extremely rare, and data on the patient described and on seven published cases are reported.

Aged↗
PubMed1995

Medullary thyroid carcinoma mimicking an autonomous functioning nodule.

A 42-year-old woman with a medullary thyroid carcinoma (MTC) inside of an autonomously functioning thyroid nodule is reported. The patient was initially diagnosed of a hyperfunctioning autonomous thyroid adenoma but the histopathological and immunohistochemistry study were diagnostic for a MTC. This is the first case of a medullary thyroid carcinoma associated with thyroid hyperfunction which was presented as a hot nodule in the scintigraphy. We propose a systematic performance of a fine needle biopsy in all thyroid nodules because of the possibility of carcinoma associated to functioning nodules could be present.

Adult↗
PubMedDate not supplied

[Immunodiagnosis of neurocysticercosis: comparative study of antigenic extracts from Cysticercus cellulosae and Taenia crassiceps].

Different antigenic extracts of Taenia solium and Taenia crassiceps were evaluated in connection with the detection of antibodies in patients with neurocysticercosis aimed at selecting immunorelevant antigens for the diagnosis of neurocysticercosis by means of the immunoenzymatic assay and immunoblotting. The vesicular fluid of T. crassiceps proved to be more sensitive (100%) and specific (86%). On using the immunoblotting technique it was also observed that this extract was the most sensitive and specific. Within the protein profile of the antigen the band of 18 kDa was mostly recognized by the serum and cerebrospinal fluid of patients with neurocysticercosis. The vesicular fluid of T. crassiceps represents an alternative in the optimization of the diagnosis of neurocysticercosis in the serum and cerebrospinal fluid and in the substitution of T. solium antigens due to its high sensitivity and specificity and to its easy obtention under controlled laboratory conditions.

Animals↗
PubMedDate not supplied

[Transient Brown-Séquard syndrome due to spontaneous spinal epidural hematoma].

Spinal epidural hematoma (SEH) is a low incidence injury. When the cause of bleeding is unknown, which occurs in 50% of the cases, we refer to it as spontaneous SEH. The clinical presentation is characterized by acute radicular pain followed by cord compression syndrome. Brown-Séquard syndrome is exceptional as a result of a SEH. Although standard treatment is prompt surgical evacuation of the hematoma, spontaneous resolution has also been reported. We present a case of spontaneous SEH in a 69 year-old man. An MRI revealed an hematoma in the right posterior epidural space extending from C6 to T2. The hematoma was manifested as a paresis of the right limbs and sensory loss of the left side below C7 level. During the first hours the neurological deficit was improved without treatment and consequently a conservative management was continued. After 72 h, the patient was completely recovered. We have reviewed the 14 cases of spinal epidural hematoma and Brown- Séquard syndrome previously reported, only 2 of them were resolved by conservative management. We conclude that when SEH presents as Brown-Séquard syndrome it usually has a more benign course and that in some cases a conservative management can be considered.

Acute Disease↗
PubMedDate not supplied

[Clinical characterisation and power simulations to detect genetic linkage in attention deficit hyperactivity disorder in Antioquian families].

INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) is a neurobehavioural disorder whose essential characteristic is a persistent pattern of inattention or hyperactivity and impulsiveness. Recent studies into prevalence carried out on the Antioquian population by our group found an overall prevalence of 15.8%, which confirms ADHD as one of the most frequent problems in infancy. The cause of this disorder is still not altogether clear; familial aggregation of ADHD points towards a genetic component. Although to date no model of inheritance has been defined, its high prevalence rate, the difficulties involved in its diagnosis and its effects on the cognitive functions, as well as the social and educational repercussions, make this disorder a problem in children's public health. AIMS: Our aim was to carry out power simulations to detect genetic linkage. PATIENTS AND METHODS: The Slink programme, which is part of Linkage package, was used in six families from the city of Medellín Antioquia, which is a region where a founding effect is likely to have taken place; this makes it a strategic zone for genetic linkage studies in complex diseases such as ADHD. RESULTS: Assuming the population to be homogenous, the lod score (Z) is greater than 3 (Z>3) and individual lod score values of between 0 and 6 were obtained for each family. CONCLUSIONS: In this paper we discuss the benefits of having multigenerational families, in Antioquia, to conduct gene mapping studies and we examine the different strategies to be developed with the findings reported here.

Attention Deficit Disorder with Hyperactivity↗
PubMedDate not supplied

[Etiology of vulvovaginitis in childhood].

A prospective study on the causal microorganism of vulvovaginitis was done to 100 ambulatory patients seen at a pediatric gynecology unit of a metropolitan hospital at Santiago, Chile, from november 1988 throughout july 1989. Samples of vaginal discharge were taken from each patient and studied for bacteria, fungi and trichomonas. Search of pinworms was also done in 55 patients by the transparent adhesive tape test. It was possible to confirm the etiology of vulvovaginitis in 81 cases. Bacteria were isolated in 68 of them, fungi in 4, Trichomonas vaginalis in one patient and pinworms in 8.

Adolescent↗