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Biomedical subjects

J M Ramos

Publications and source records attributed to J M Ramos.

119 records · Page 7Linked to original sources
PubMedDate not supplied

Influence of the shape of the experimental room on spatial learning in rats.

Rats and other mammals can orient themselves in their habitat and locate various goals using different learning strategies. When a cartographic or local strategy is used, the animals construct and store in their long-term memories a complex representation of the extramaze space. However, exactly what constitutes the behaviorally key components of the extramaze space is still little known. The purpose of this study was to investigate whether the shape of the environment that surrounds the animal is an informative factor when a cartographic strategy is used. Two experiments were performed in which the rats were trained to find food in the goal arm of a four-arm, plus-shaped maze. Experiment 1 shows that lesions to the hippocampus impair the acquisition of this task, which suggests that in fact, a cartographic strategy is necessary to solve it. In Experiment 2, in which only one group of neurologically intact rats was used, we directly manipulated the shape of the space around the maze. The results showed that once the animals have learned the task, the hiding of all the extramaze single landmarks while keeping intact the general shape of the experimental room does not affect performance. Only when the shape of the surrounding space was modified did the performance deteriorate significantly. These results are discussed in relation to the different components of the extramaze environment and the contribution of each of them to the spatial learning.

Animals↗
PubMedDate not supplied

[Chickenpox outbreak in Herrera del Duque, Badajoz, Spain].

INTRODUCTION: Chickenpox is a worldwide disease with high morbidity but few complications, although complications can be sevre in immunocompromised individuals and healthy adults. The annual chickenpox rate declared to the National Notification Disease Surveillance System is approximately 5 cases per 1,000 inhabitants in Extremadura (Spain). The aim of this study was to identify and describe the characteristics and cost of an epidemic outbreak of chickenpox in Extremadura. METHODS: Between November 2000 and March 2001, a descriptive study was performed. Cases of chickenpox were actively sought in a cohort of schoolchildren in Herrera del Duque (Badajoz). The protocols of the Monitoring Network of the Autonomous Community of Extremadura was used for case definition. Microbiological confirmation was performed by isolation of the virus and the presence of IgM and IgG markers in serum. We analyzed the direct and indirect tangible costs as well as the intangible costs of the outbreak. RESULTS: Seventy-five cases were identified, of which 94.7% occurred in children aged between 1-9 years, mainly boys. The attack rate was 18.5 cases per 1,000 inhabitants and 68.2% occurred in children aged less than 10 years charing a home. The clinical course was benign, without hospital admissions or complications. A total of 71.6% of children aged between 3 and 8 years were susceptible. A possible temporary aggregation of cases in the school was analyzed and a relative risk of 5.01 (p < 0.0001) was obtained. The virus was isolated in the 4 vesicle samples studied and serology was positive (IgM) in the 9 serum samples studied. The total cost of the outbreak was of 927,21 e, with a mean of 12,53 e per case and 205 school days lost. CONCLUSION: A chickenpox outbreack was confirmed in Herrera del Duque, with person-to-person transmission, affecting children aged between 1 and 9 years. The high susceptibility of the pupils, the characteristics of teaching, and the meetings prior to the carnivals played a determining role in the transmission of the epidemic. The estimated cost of this outbreak was 76% less than the cost that would have been generated by single-dose vaccination of the 75 individuals who contracted the disease.

Chickenpox↗
PubMedDate not supplied

Resolution of methamphetamine stereoisomers in urine drug testing: urinary excretion of R(-)-methamphetamine following use of nasal inhalers.

The objective of this study is to determine whether R(-)-methamphetamine inhaled from nasal inhalers produces positive methamphetamine results in currently used urine drug screening procedures and to present a rapid method for distinguishing the optical isomers of methamphetamine. Urine from three subjects inhaling from a Vicks Nasal Inhaler every 20 min for six hours tested positive for methamphetamine by EMIT, Toxilab, TDx, and GC/MS. The chiral derivatizing reagent N-trifluoroacetyl-L-prolyl chloride (L-TPC) was used to form methamphetamine diastereomers allowing rapid identification of each stereoisomer of methamphetamine present in the urine samples. Urine samples positive for amphetamines during routine drug screening were determined to consist of a racemic mixture of methamphetamine. The isomeric composition of methamphetamine present in a urine sample indicates the probable source of the drug.

Administration, Inhalation↗
PubMedDate not supplied

[Exercise 2D-Doppler echocardiography, for the evaluation of aortic valve prostheses].

STUDY OBJECTIVE: Exercise evaluation of eccentric monocuspid aortic prosthetic valves. DESIGN: Prospective study, using 2D Doppler echocardiography to analyse resting and exercise aortic flow patterns. SETTING: Laboratory of Echocardiography at Santa Marta Hospital. PATIENTS: Sequential sample of 28 patients with aortic prosthesis (19 Bjork-Shiley and 9 Hall-Kaster), without evidence of either cardiac failure, coronary artery disease, prosthesis dysfunction or stress test contraindication. INTERVENTIONS: Transaortic basal and exercise flow record, using Doppler echocardiography to analyse: instantaneous peak velocity (pv) and gradient (pg), systolic time intervals, heart rate (hr) and stress test time (stt). The patients were divided in two groups A (prosthesis valve size 19 and 21) and B (greater than 21). RESULTS: Technical success: 84%. basal pv ranged from 1.6 to 4.5 m/s in group A and 1.7 to 3 m/s in B. Rest pg was 35 +/- 1% mmHg--Group A--and 20 +/- 8 mmHg in B (p less than 0.01), increasing with stress test respectively to 62 +/- 26 (p less than 0.01) and 36 +/- 12 mmHg (p less than 0.001). 73% of group A patients had exercise pg greater than 50 mmHg. The correlation between basal and exercise pg was significant (r = 0.91 p less than 0.001). At rest the systolic time intervals revealed a significant difference between the two groups (p less than 0.05), while only the ejection time was significant with stress test (p less than 0.01). Exercise hr and stt were greater in group B-p = NS. CONCLUSIONS: These exercise Doppler echocardiography data suggest that mechanical moncuspid aortic prosthesis 19, 21 and same 23, result in left ventricular outflow obstruction mainly during exercise; these facts should be taken into account when aortic prosthesis insertion is considered. Given the good correlation between resting and exercise peak gradient, Doppler stress test is not routinely recommended in clinical practice.

Adult↗
PubMedDate not supplied

[Osteoarticular infections by Salmonella non-typhi].

BACKGROUND: The aim of this study was to know the clinical characteristics of osteoarticular infection by Salmonella non typhi (SNT) in Spain. PATIENTS AND METHODS: The medical records of 14 patients with osteoarticular infection by SNT from January 1970 to December 1992 were reviewed. RESULTS: Over the above mentioned 23 years, 1334 patients had been diagnosed with one or more SNT isolations, with 14 (1%) having osteoarticular infection. Seven patients had septic arthritis, 3 osteomyelitis and 4 mixed infection (arthritis and osteomyelitis). Thirteen patients (93%) presented with underlying systemic disease (immunosuppression 12 cases [86%] and hemoglobinopathy 1 case [7%]) and 5 (36%) had predisposing osteoarticular disease. The most commonly affected joint was the knee (9.58%). Involvement was monoarticular in 8 episodes (73%). Out of the 7 cases with osteomyelitis, 4 (57%) were secondary to an articular foci and 3 (43%) were of hematogenic origin. The femur (4 cases, 44%) and the tibia (4 cases, 44%) were the most frequent localizations. On nine occasions (64%) the cultures remained positive 7 days after initiation of antibiotic treatment. Only one patient died as a consequence of the articular infection. CONCLUSIONS: Osteoarticular infection by Salmonella non typhi should take the existence of immune disorders into account.

Adolescent↗
PubMedDate not supplied

[Epidemiological profile of non-typhi salmonellosis in a hospital in urban Madrid (1980-1994)].

BACKGROUND: The aim of this study was to describe the epidemiologic profile of non-typhoid salmonellosis at a general hospital in the metropolitan area of Madrid. METHODS: A descriptive and retrospective study of non-typhoid salmonellosis diagnosed at Microbiology Department of Fundación Jiménez Díaz from May 1980 to December 1994 was done. RESULTS: Non-typhoid Salmonella (NTS) was identified in 1796 specimens of 1463 patients, 520 (35.5%) were under 15 years and 943 (64.5%) were over 14 years. The infection was intestinal in 1288 (88%) cases, bacteremic in 129 (8.8%) and focal in 46 (3.1%). The extraintestinal infection was most frequent in patients over 14 years (15.5% versus 5.6%; p < 0.001). From 1987, 34 adults patients with human immunodeficiency virus (HIV) infection developed salmonellosis. The infection was due to Salmonella serogroup B (29.4%) and the extraintestinal manifestations (58.8%) were most frequent in HIV-infected patients than in the control-group (p = 0.004 and p < 0.001, respectively). Salmonella serogroup D was identified in 1041 (71.2%) episodes, and serogroup B in 259 (17.7%). Salmonella serogroup B and C were more resistant to one or more antibiotics than Salmonella serogroup D (p = 0.001). Resistance of NTS (principally Salmonella serogroup B) for one or more antibiotics (particularly ampicillin and chloramphenicol) increased significantly during the period of study (p < 0.001). CONCLUSIONS: The HIV-infected patients had a predisposition to develop extraintestinal Salmonella infections. Resistance of NTS for antibiotics, especially Salmonella serogroup B, has significantly increased during the last years.

Adolescent↗
PubMedDate not supplied

[Bacteremia caused by Alcaligenes (Achromobacter) xylosoxidans. Description of 3 cases and review of the literature].

BACKGROUND: Alcaligenes (Achromobacter) xylosoxidans occasionally cause infections, mainly in immunocompromised hosts. METHODS: Three cases of bacteremia due to A. xylosoxidans observed at the Fundación Jiménez Díaz between 1985-1994 were described. Moreover, 38 single cases of bacteremia due to A. xylosoxidans and 21 episodes associated with outbreak were reviewed by using computerized bibliography data base MEDLINE (1970-december 1994). RESULTS: From 41 patients with bacteremia (including our 3 cases) reviewed, 27 were immunosuppressed hosts (twenty had neoplasia disease). The most common clinical presentation was primary bacteremia (11 cases, 27%) and pneumonia (10, 24%), followed by catheter-associated bacteremia (8, 20%), meningitis (4), bacteremia from abdominal cavity (4), endocarditis (3) and pyelonephritis (1). The mortality rate was higher (39%), specially in patients whom were a intensive care unit acquisition (87%), and illness with endocarditis (100%). No patient with catheter-related bacteremia died. All of 21 outbreak episodes of bacteremia had a autolimited form and low mortality (4.8%). CONCLUSION: A. xylosoxidans is a microorganism with demonstrated capacity of cause bacteremia, mainly in immunocompromised hosts, with high mortality rates. Sometimes, it causes outbreaks of bacteremia with low mortality.

Adolescent↗