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Biomedical subjects

S Santiago

Publications and source records attributed to S Santiago.

At least 19 recordsLinked to original sources
PubMed2005

Spread of Coxiella burnetii infection in a flock of sheep after an episode of Q fever.

In October 1998, two abortions associated with Coxiella burnetii occurred in a group of 34 pregnant ewes in the sheep flock belonging to INRA Tours-Nouzilly. The flock was kept in groups of approximately 40 ewes, which were housed together in the same accommodation. The prevalence of C burnetii infection in the groups was investigated by using ELISA and PCR tests, which revealed a high prevalence of C burnetii. The ewes were treated with oxytetracycline to reduce the shedding of C burnetii and to prevent further abortions. Nevertheless, five abortions attributed to C burnetii occurred in January and March 1999 in three groups of ewes, and 24 of the ewes still shed the bacteria into their vaginal tracts. In addition, a serological study was carried out during the first year of life of the female lambs born in 1999 and 2000; 12 per cent of 113 lambs born in 1999 were seropositive for C burnetii by ELISA, and half of the ELISA-positive lambs were born either to serologically positive ewes or to dams that excreted the pathogen into their vaginal tracts. However, all the 150 lambs born in 2000 were ELISA-negative, suggesting that the preventive measures undertaken had suppressed both the abortions and the shedding of C burnetii, and reduced the transmission of the agent.

Abortion, Veterinary↗
PubMed2005

Assessment of the essential element and heavy metal content of edible fish muscle.

The aim of this work was to determine the concentrations of some essential and toxic elements in the muscle of ten species of commercial fish consumed in Portugal. We combined two different techniques for determination of the elements--energy-dispersive X-ray fluorescence (EDXRF) was used to quantify K, Ca, Fe, Zn, Se, Rb, and Sr and flame atomic-absorption spectrometry for analysis of Cr, Ni, Cu, Cd, Hg, and Pb. The latter technique was used because of its higher sensitivity, because these elements were not detected by EDXRF. The results obtained show a similar pattern for the trace elements. K and Ca are present at the highest concentrations in all the samples studied, from 0.6-1.3% and from 0.04-0.08%, respectively, followed by Zn, Fe, Sr, Se, and Rb. Sr is present at higher concentrations than Rb in all the species studied except meagre. Concentrations of the elements in octopus do not follow this pattern--Fe is present at a higher concentration than Zn. Low concentrations of Cr (0.66-1.5 microg g(-1)), Ni (0.11-0.24 microg g(-1)), Cd (0.01-0.08 microg g(-1)), Hg (0.49-2.74 microg g(-1)), and Pb (0.02-0.06 microg g(-1)) were observed in all the samples analysed. The concentration of Hg was highest in Helicolenus dactylopterus--5.4 microg g(-1) in one sample.

Animals↗
PubMed2005

Abrogation of the alloreactive responses of cadaveric donor intestinal lymphocytes by intraoperative Campath-1H exposure.

A number of recent reports in clinical and experimental intestinal transplantation have suggested that the donor lymphocytes present in and around the gastrointestinal system are potent mediators of graft-versus-host (GvH) reactivity and that GvH responses may contribute to posttransplant morbidity. Therefore, we have tested the proliferative and cytotoxic capabilities of gut-associated lymphocytes from cadaveric donors obtained prerevascularization (pre-r) and about 6 hours postrevascularization (post-r) in recipients pretreated with Campath-1H antibody (alemtuzumab). Mixed lymphocyte reactions (MLR) were performed with lymphoid cells isolated from intestinal epithelial mucosa, lamina propria, and lymph nodes. The pre-r lymphocytes responded strongly to both the recipient and third-party alloantigenic stimulating cells. However, similar preparations from the post-r samples responded in MLR at significantly lower levels (P < .01). This post-r decrease in responsiveness was not observed in similar lymphocyte samples obtained from donors of recipients not treated with Campath-1H. Both the pre-r and post-r samples had similar flow cytometric profiles, suggesting that there was no receptor loss in these lymphoid tissues by the short-term 6-hour exposure to Campath-1H given to the recipient. Conversely, in preliminary experiments where the donor were treated with Campath-1H, it was observed that very few lymphocytes could be obtained from intestinal tissues (n = 3). These results suggested that Campath-1H treatment of the recipient could bring about a drastic reduction in an otherwise strong GvH reactivity by the donor intestinal immune cells.

Alemtuzumab↗
PubMed2004

Assessment of water quality and toxicity of polluted Rivers Fez and Sebou in the region of Fez (Morocco).

Water quality assessment in the region of Fez based on the physicochemical and ecotoxicological investigations is presented. The results indicate that sites located close to the most urbanized and industrialized areas are severely impaired. The major water quality problems are: low dissolved oxygen (DO), high turbidity, organic matter and ammonia contents, severe chromium and copper pollution and high acute and chronic toxicity. This results in the loss of the aquatic life which is still flourishing in the Fez River upstream from the Fez Medina. Remote sites downstream show signs of physicochemical recovery. However, even there, bioassays showed significant acute and chronic toxicity. Well water in the region of Fez has moderately poor water quality with nitrate and metal enrichments. Use of water for drinking or for agriculture from the rivers or from some wells without treatment may expose the population to health risk.

Biological Assay↗
PubMed2004

Study of the development and evolution of neointestine in a rat model.

The implantation of fragmented rat intestinal epithelium into the omentum of syngeneic animals results in the formation of a cyst containing neointestine. The purpose of our project was to study the evolution of this neointestine-containing cyst over time. Harvested jejunum and ileum of neonatal DA rats (6 to 8 days old) was digested with collagenase type XI and dispase at room temperature. The resulting organoid units, containing clusters of intestinal epithelium with stem cells were seeded onto a polyglactin polymer mesh (100000 units per mesh). The absorbable mesh was implanted in the omentum or peritoneal wall of an adult syngeneic animal. Animals were sacrificed at weekly intervals to harvest the neointestinal cysts. The lumen of the neointestine cysts was full of mucous while the wall of the cyst was covered by intestinal mucosa. H&E staining of the cyst demonstrated the morphology of intestinal epithelium; PAS staining identified goblet cells. The size of the cyst was maximal between 4 and 8 weeks postimplantation tending to regress thereafter. Neointestinal cysts are a consistent finding after implantation of intestinal epithelium organoids into the omentum or peritoneal wall in the rat model. The cysts reach a maximal size at 4 to 8 weeks postimplantation, tending to regress thereafter.

Animals↗
PubMed2002

[Sensory neuropathy and primary biliary cirrhosis].

Primary biliary cirrhosis (PBC) may associate an axonal neuropathy, a somatic and autonomic neuropathy and a very infrequently sensory neuropathy (with or without xanthomata). The aim of this paper is to describe the case of a 46 year old man diagnosed with PBC in stage I-II and a progressive sensory neuropathy (axonopathy) confined to his upper limbs with distal predominance. It had progressed slowly an began asymmetrically. A complete clinical study excluded other causes of neuropathy. We followed him clinically and electromyographically and he remains stable after two years evolution. The sensory neuropathy in this case, a primary biliary cirrhosis, is compatible with an assymetric sensory neuropathy limited to the upper limbs with assymmetric beginning.

Electromyography↗
PubMed2000

Neurophysiological studies of thin myelinated (A delta) and unmyelinated (C) fibers: application to peripheral neuropathies.

Dysfunction of small fibers may appear in isolation or associated with large fiber lesions. In some acute neuropathies, such as pandysautonomia, small-fiber impairment is relatively pure but it may also appear in disorders with prominent somatic damage, such as Guillain-Barré syndrome, in which autonomic failure worsens the prognosis. At the present time, chronic idiopathic distal small-fiber neuropathy is diagnosed more frequently, and in some prevalent disorders, such as diabetic or amyloidotic polyneuropathies, small-fiber dysfunction is very noticeable. In pure autonomic failure, a peripheral autonomic failure exists, distinguishing it from multiple-system atrophy. Complex regional pain syndrome is a severe condition in which small fibers are responsible for disabling signs and symptoms, and only instrumental recordings lead to the proper treatment. Standard neurophysiological techniques evaluate large myelinated fibers exclusively. Small-fiber polyneuropathy has been considered as a type of somatic neuropathy, but thin myelinated and unmyelinated fibers are responsible not only for temperature and pain perception but also autonomic function. For instance, full autonomic evaluation is needed in some clinical situations such as autonomic failure in the elderly or orthostatic intolerance syndrome. To evaluate small-fiber impairment we need a battery of sensitive, reproducible, specific and noninvasive tests covering somatic and autonomic systems. In this review, we describe and analyze a number of neurophysiological techniques used to diagnose and characterize small-fiber dysfunction in humans. These include cardiovascular monitoring, sudomotor testing, pupillary responses and quantitative sensory tests, and also to some extent thermography and laser evoked potentials. The use of such techniques has proven useful not only for diagnosis, but also to guide adequate therapy and optimize follow-up.

Electrophysiology↗
PubMed2000

Accuracy and clinical impact of mediastinal lymph node staging with FDG-PET imaging in potentially resectable lung cancer.

To determine the sensitivity, specificity, and accuracy of staging mediastinal nodal disease in potentially resectable lung cancer using fluorodeoxyglucose-positron emission tomography (FDG-PET), computed tomography (CT), or both and compare these results to surgical staging. We also assessed whether PET scanning results changed clinical management. From 1992 to 1997, 50 patients underwent CT, and PET scanning before or close to the time of surgical staging. Sensitivity, specificity, accuracy, and predictive values were then calculated based on pathology results. A retrospective review of the records was performed to determine how PET results affected clinical treatment decisions. Forty-seven of 50 patients had non-small-cell lung cancer. The prevalence of pathologically confirmed mediastinal and hilar involvement was 38%. The sensitivity, specificity, and accuracy of mediastinal disease staging were as follows: CT alone = 73%, 77%, 76%; PET alone = 73%, 94%, 87%; PET + CT = 82%, 96%, 91%, respectively. PET was more specific and accurate than CT (p = 0.025). The results of PET changed management decisions in 12 of 50 cases (24%). Using FDG-PET in conjunction with CT scanning provides the most accurate staging of mediastinal disease in lung cancer by contributing complementary information. Furthermore, PET can affect clinical decision-making and allow some patients considered unresectable a chance for resection.

Adult↗
PubMed1999

Mouse models of tumor development in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is a prevalent familial cancer syndrome resulting from germ line mutations in the NF1 tumor suppressor gene. Hallmark features of the disease are the development of benign peripheral nerve sheath tumors (neurofibromas), which can progress to malignancy. Unlike humans, mice that are heterozygous for a mutation in Nf1 do not develop neurofibromas. However, as described here, chimeric mice composed in part of Nf1-/- cells do, which demonstrates that loss of the wild-type Nf1 allele is rate-limiting in tumor formation. In addition, mice that carry linked germ line mutations in Nf1 and p53 develop malignant peripheral nerve sheath tumors (MPNSTs), which supports a cooperative and causal role for p53 mutations in MPNST development. These two mouse models provide the means to address fundamental aspects of disease development and to test therapeutic strategies.

Animals↗
PubMed1999

Clinical features and genetic analysis of a Spanish family with spinocerebellar ataxia 6.

OBJECTIVE: To present the clinical features and DNA analysis of a Spanish SCA6 family. MATERIAL AND METHODS: Four symptomatic members of the family (mean age at onset: 53.75+/-5.21) were examined. SCA6 CAG trinucleotide repeat was analysed in the proband by the polymerase chain reaction (PCR). RESULTS: Early dysphagia, ophthalmoparesis and neck dystonia in the oldest patient, without the loss of vibratory and proprioceptive sensation supporting the theory of phenotypic variability within families with SCA6. Our results are in accordance with the theory that the size of the repeat pattern correlates with the age at onset of the symptoms. Analysis of the SCA6 CAG trinucleotide repeat at the CACNA1A gene in the patient's DNA demonstrated an expanded allele of 22 CAG repeat units. CONCLUSIONS: This study identifies phenotypic differences in the surviving kindred. The diagnosis of SCA6 in family members or single affected patients can be made by direct molecular analysis. This makes predictive testing possible.

Adult↗
PubMed1998

Hemoptysis as the sole presentation of Pasteurella multocida infection.

Pasteurella multocida has been implicated as the cause of a variety of respiratory conditions (eg, bronchitis, pneumonia, lung abscess, empyema), but hemoptysis has been noted only in conjunction with other lung conditions. We report a case in which hemoptysis was the sole manifestation of Pasteurella infection. The patient was a middle-aged man with severe obstructive lung disease and exposure to cats. Diagnosis was made by bronchoscopy and high-dose penicillin was required for resolution.

Animals↗
PubMed1994

Nasal mechanical ventilation for hypercapnic respiratory failure in chronic obstructive pulmonary disease: determinants of success and failure.

OBJECTIVES: To evaluate the efficacy of nasal mechanical ventilation in patients with chronic obstructive pulmonary disease and hypercapnic respiratory failure and to identify predictors of success or failure of nasal mechanical ventilation. DESIGN: Prospective case series. SETTING: Medical intensive care unit in Veterans Administration Medical Center. PATIENTS: Twelve chronic obstructive pulmonary disease patients treated during 14 episodes of hypercapnic respiratory failure. INTERVENTIONS: Nasal mechanical ventilation in addition to conventional therapy to treat hypercapnic respiratory failure. Patients underwent nasal mechanical ventilation for at least 30 mins, or longer if the therapy was tolerated. Responses to therapy and arterial blood gases were monitored. MEASUREMENTS AND MAIN RESULTS: Half of the episodes were successfully treated with nasal mechanical ventilation. There were no differences in age, prior pulmonary function, baseline arterial blood gases, admission arterial blood gases, or respiratory rate between those patients successfully treated and those patients who failed nasal mechanical ventilation. Unsuccessfully treated patients appeared to have a greater severity of illness than successfully treated patients, as indicated by a higher Acute Physiology and Chronic Health Evaluation II score (mean 21 +/- 4 [SD] vs. 15 +/- 4; p = .02). Unsuccessfully treated patients were edentulous, had pneumonia or excess secretions, and had pursed-lip breathing, factors that prevented adequate mouth seal and contributed to greater mouth leaks than in successfully treated patients (the mean volume of the mouth leak was 314 +/- 107 vs. 100 +/- 70 mL; p < .01). Successfully treated patients were able to adapt more rapidly to the nasal mask and ventilator, with greater and more rapid reduction in PaCO2, correction of pH, and reduction in respiratory rate. CONCLUSIONS: Patients who failed nasal mechanical ventilation appeared to have a greater severity of illness; they were unable to minimize the amount of mouth leak (because of lack of teeth, secretions, or breathing pattern) and were unable to coordinate with the ventilator. These features may allow identification of poor candidates for nasal mechanical ventilation, avoiding unnecessary delays in endotracheal intubation and mechanical ventilation.

Acute Disease↗
PubMed1991

Screening for sleep apnea using pulse oximetry and a clinical score.

Confirmation of the diagnosis of OSA currently requires overnight polysomnography. This study evaluates the usefulness of pulse oximetry together with a clinical score in identifying OSA. Forty patients were assigned a clinical score based on the presence or absence of loud snoring, observations of interrupted breathing during sleep, hypersomnolence, obesity and essential hypertension. Each underwent a night of domiciliary pulse oximetry followed by nocturnal polysomnography. Significant OSA was confirmed in 26. All 15 patients with positive pulse oximetry tracings had significant OSA (apnea index greater than or equal to 10). Five of eight with negative tracings were also shown to have significant OSA along with six of the seven patients with inadequate or indeterminate tracings. Clinical scores were significantly different for those with and without OSA. This study confirms the usefulness of nocturnal pulse oximetry in establishing the diagnosis of OSA and highlights the value of a clinical score in improving its sensitivity as a screening tool.

Adult↗