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Biomedical subjects

J M Ramos

Publications and source records attributed to J M Ramos.

At least 19 recordsLinked to original sources
PubMed2006

Vibrational normal modes of diazo-dimedone: a comparative study by Fourier infrared/Raman spectroscopies and conformational analysis by MM/QM.

The 2-diazo-5,5-dimethyl-cyclohexane-1,3-dione (3) was synthesized and the FT-IR/Raman spectra were measured with the purpose of obtain a full assignment of the vibrational modes. Singular aspects concerning the -CNN oscillator are discussed in view of two strong bands observed in the region of 2300-2100 cm(-1) in both, Infrared and Raman spectra. The density functional theory (DFT) was used to obtain the geometrical structure and for assisting in the vibrational assignment joint to the traditional normal coordinate analysis (NCA). The observed wavenumbers at 2145 (IR), 2144(R) are assigned as the coupled nu(NN)+nu(CN) vibrational mode with higher participation of the NN stretching. A 2188 cm(-1) (IR) and at 2186 cm(-1) (R) can be assigned as a overtone of one of nu(CC) normal mode or to a combination band of the fundamentals delta(CCH) found at 1169 cm(-1) and the delta (CCN) found at 1017 cm(-1) enhanced by Fermi resonance.

Azo Compounds↗
PubMed2005

Severe toxicity associated with the combination of tenofovir and didanosine: case report and review.

The combination of tenofovir and didanosine results in an increase in the didanosine plasma exposure and might augment the risk for didanosine toxicity. Although pharmacokinetic studies support a didanosine dose reduction to 250 mg when used concurrently with tenofovir in patients weighing at least 60 kg, no data are available in lower-weight patients. We describe a case of lactic acidosis and acute liver failure in a low-weight patient receiving tenofovir and a reduced dose of didanosine (200 mg/day). To our knowledge, this is the first case of severe toxicity associated with a reduced dose schedule of didanosine. Previous cases of severe toxicity associated with the combination of tenofovir and didanosine are reviewed.

Acidosis, Lactic↗
PubMed2005

[Risk of superinfection related to antibiotic use. Are all antibiotics the same?].

The aim of this study was to analyze the effect of using different antibiotics on the risk of acquiring a bacterial or fungal superinfection in hospital-acquired infections. A systematic review of the literature using the PubMed (Medline) database from January 1990 to December 2003 was performed. We selected only those studies with at least 25 patients in each arm in which the clinical efficacy of several antibiotics (third generation cephalosporins, fluorquinolones, piperacillin-tazobactam and carbapenems) were evaluated for the treatment of severe infections, and which specifically reported the rate of superinfection. The microorganisms most frequently implicated in the development of superinfection were: Candida spp. (42.3%), Enterococcus spp. (18.8%), enterobacteria (13.8%), Staphylococcus spp. (9.5%), Pseudomonas aeruginosa (6.6%), and Clostridium difficile (4.1%). The antibiotic most frequently related to superinfection was ciprofloxacin (38.1%), followed by cefotaxime (23.3%), imipenem (12%), meropenem (10.2%), and cefepime (6.1%). The lowest percentage of superinfection was observed with the use of piperacillin-tazobactam (5.4%).

Anti-Bacterial Agents↗
PubMed2005

[Spanish scientific production in antimicrobial agents and susceptibility procedures during period 1990-2002].

The aim of this study was to analyze the scientific production of Spanish authors on antimicrobial agents and susceptibility tests during the period 1990-2002. Articles from Spanish scientific institutions of microbiology, bacteriology, mycology and parasitology published and recorded in the MEDLINE database (WEBSPIRS version 4.2) during the period 1990-2002 were selected. Only articles about antimicrobial agents and susceptibility procedures were reviewed. A total of 5,259 documents were analyzed, of which 1,041 (19.8%) were about antimicrobal agents. The annual number of documents increased by two-fold (from 48 in 1990 to 101 in 2002). The journal that published most documents was Antimicrobial Agents and Chemotherapy, with 183 (17.1%). The main field of interest of the documents was antimicrobial agents and susceptibility tests (765; 73.5%) and in vitro resistance analyses (265; 25.5%). The highest number of contributions came from hospitals (571; 54.9%), followed by universities (351; 33.7%). The institutions with most documents published were the Ramón y Cajal Hospital (8.6%), and Seville University Faculty of Medicine (6%). The most productive autonomous communities were Madrid (43.4%), Catalonia (16.4%) and Andalusia (4.7%). A total of 787 documents (75.6%) were published in journals with impact factors and the mean expected impact factor was 2.390 +/- 1.546. It was concluded that the scientific production of Spanish researchers in antimicrobial agents had increased during the period 1990-2002, and that hospitals were the most productive institutions in this area of microbiology, with the main areas of interest being antimicrobial agents and susceptibility tests.

Anti-Bacterial Agents↗
PubMed2004

Publication of European Union research on infectious diseases (1991-2001): a bibliometric evaluation.

The study presented here analyzed the contents of 36 international infectious diseases journals from 1991 to 2001 to determine the number of reports prepared by authors in the European Union and to compare the per country scientific productivity. Articles included in the study were identified using the PubMed website. The number of publications in infectious disease journals produced by authors in the European Union experienced an exponential growth from 461 (19.2% of world production) in 1991 to 2,401 (35.9%) in 2001. The mean impact factor increased from 2.259 in 1991 to 3.001 in 2001. The leading countries in the total number of publications were the UK, France, and Germany. After taking population figures into account, Sweden, Denmark, and Finland headed the list, and after correcting for gross domestic product, the greatest producers were Sweden, Finland, and the UK. Overall, the scientific production and repercussion index of European Union research on infectious diseases experienced a notable rise during the last decade of the 20th century.

Bibliometrics↗
PubMed2004

Epidemiological and clinical characteristics of occult bacteremia in an adult emergency department in Spain: influence of blood culture results on changes in initial diagnosis and empiric antibiotic treatment.

A prospective study was carried out to analyze the usefulness of blood culture results for adult patients who were discharged from the emergency department with bacteremia. Over a 29-month period, 110 patients with significant bacteremia who were seen in the emergency department and discharged home were studied. The mean age of the patients was 61.8 years. The most frequent initial major diagnosis was urinary tract infection (UTI) (n=63; 57.3%). Gram-negative organisms were isolated in 79 (71.8%) cases. A change in diagnosis (44.5% cases) was more common when the initial diagnosis was something other than UTI or when empiric antimicrobial therapy was ineffective or was not given (P<0.001). The significant predictors of modification of the initial empiric antibiotic therapy were ineffective empiric antimicrobial therapy and transfer of the patient from the emergency department to an infectious diseases outpatient clinic (P=0.01). Blood culture results may be useful for achieving the correct diagnosis in adult patients with bacteremia and for guiding treatment in the subsequent management of outpatients.

Adult↗
PubMed2004

Characteristics of louse-borne relapsing fever in Ethiopian children and adults.

Louse-borne relapsing fever (LBRF) is endemic in Ethiopia. The epidemiological and clinical aspects of LBRF and the differences between the infection in children and that in adults were investigated in a rural hospital in Ethiopia. During the 5-year study (1997-2002), 197 patients had a confirmed diagnosis of LBRF. Most (62.1%) of the cases were children under 15 years of age. The adult cases (i.e. those aged > or =15 years) were far more likely to present with headache (76.9% v. 40%; P <0.001), musculo-skeletal pains (61.5% v. 30.5%; P <0.001), dizziness (64% v. 39%; P =0.002) and bleeding (16.9% v. 3.8%; P =0.005) than the paediatric. The overall level of case fatality was 6.4%. Death appeared to be significantly associated with adulthood (P =0.01), delay in consultation (P =0.026) and the presence of vomiting (P =0.023). LBRF is clearly still a public-health problem in Ethiopia, where the clinical manifestations of the disease differ according to the age of the case.

Adolescent↗
PubMed2004

[A 41 year-old female with abdominal pain and fever of 24 hours].

A 41 year-old female with intrauterine contraceptive device (ICD) from 8 year ago that complained fever and abdominal pain during 24 hours and leucocytosis. The radiology examination tests showed cegal, appendiceal, and right ovary enlargement with swollen of fat adjacent. In the differential diagnosis should be include: appendicitis, diverticulitis, chronic inflammatory digestive disease or mesenterical adenitis. In the differential diagnosis included: ovarian neoplasm, endometriosis, ectopic pregnancy, ovarian torsion and pelvic inflammatory diseases. From pelvic infections, it is import consider pelvic inflammatory disease, genital tuberculosis and pelvic actinomycosis. With the antecedent of ICD, the clinic and the radiological finding as abdominal mass with invasion of adjacent structures and absence of adenopathy; the first diagnosis is a abdominopelvic actinomycosis and the second is a genital tuberculosis.

Abdominal Pain↗
PubMed2001

Hippocampal damage in rats disrupts decrements in the processing of an intramaze landmark in a spatial task.

Using a four-arm plus-shaped maze, rats with neurotoxic lesions in the dorsal hippocampus were trained in a spatial reference memory task in which both the extramaze constellation of stimuli and an intramaze landmark (a piece of sandpaper covering the floor of the goal) indicated the location of the goal arm. After reaching criterion, animals were given two transfer tests in order to investigate how much they had learned about the intra and extramaze cues. Results showed that during the intramaze transfer, based exclusively on the intramaze cue, hippocampal rats produced a performance clearly superior to that of the controls. Importantly, the average percentage of correct responses recorded in the hippocampal group during the extra versus the intramaze transfer test was similar. Thus, no decremental processing of the intramaze cue was detected in the lesioned group. In contrast, control rats showed a decremental processing of the intramaze landmark performing worse during the intramaze transfer as compared with the extramaze transfer. These results support the view that the hippocampus regulates decremental changes in the processing of normally irrelevant stimuli, extending this claim into a spatial domain.

Animals↗
PubMed2001

Rats with hippocampal lesions can learn a place response, but how long can they retain it?

Previous research has shown that electrolytic hippocampal lesions do not affect the acquisition of a place response if a special training procedure is used. However, 24 days later, the hippocampal rats manifest a profound deficit in the retention of the spatial information (J. M. J. Ramos, 2000). The goal of the present study was, therefore, to investigate how long the hippocampal rats can retain a place response. Results showed that, 3 days after the end of the training, lesioned rats remembered as well as the control rats, but this was no longer true 6 or 12 days after the training. This retention deficit was not observed when the spatial information was acquired by means of a guidance strategy. These results suggest that, when a special training procedure is used, the hippocampus is not necessary for the learning of a place task but is required for the formation of long-term spatial memory.

Animals↗
PubMed2000

Retention of spatial information in hippocampally damaged rats overtrained on a cartographic task.

Hippocampal rats were overtrained on a cartographic task until they reached a performance equal to that of the control group. Twenty-four days later, during a retraining period, lesioned rats showed a profound retention deficit as compared to controls. However, Expt. 2 shows no retention deficit when a guidance strategy is used to acquire the spatial task. These results suggest that the hippocampus is crucial for long-term retention/consolidation of allocentric spatial information.

Animals↗
PubMed2000

The hippocampus and flexible spatial knowledge in rats.

Lesions to the hippocampal system in rats result in a profound impairment of place or locale spatial learning although other learning strategies remain unaltered. The main objective of the present study was to investigate whether the spatial knowledge preserved in the hippocampal animals can be expressed flexibly under conditions different from those of the acquisition period. Rats with neurotoxic lesions to the dorsal hippocampus and sham-operated subjects were trained to reach the goal arm in a four-arm plus-shaped maze using a constant starting arm. During the training a transparent plexiglas barrier divided the maze in two equal halves in such a way that the animals could only travel from the starting arm to the goal arm, not having access to the remaining 50% of the maze. After seven days of training, a transfer test was used in which the starting arms were the two arms from which the animals had not started during the training phase. Results indicated that the lesioned rats made significantly more errors than the control subjects. But the most interesting results revealed that the kind of error made by the lesioned animals was congruent with the turn that they had to make during the acquisition phase in order to access the goal arm (reinforced). These results suggest that when the hippocampus is damaged a preserved highly inflexible egocentric strategy is employed to solve the spatial problem.

Animals↗
PubMed2000

Long-term spatial memory in rats with hippocampal lesions.

In animal models of human amnesia, using lesion methods, it has been difficult to establish the role played by the hippocampus in the formation of long-term spatial knowledge. For example, lesions sustained after acquisition have generally produced a flat retrograde amnesia for spatial information. These results have not made it possible to dissociate the participation of the hippocampus in retrieval/performance processes from its participation in consolidation/retention. The present study was designed to investigate if electrolytic hippocampal lesions made before training lead to a deficit in the long-term retention of spatial knowledge when the rats show equal performance levels during the acquisition. Results show that lesioned rats learn a place response just as well as the control rats when, during the training, an intramaze cue orients the animal in its navigation towards the goal arm. One day after reaching criterion, lesioned and control rats remember the task perfectly during a transfer test in which the intramaze signal used previously is not present. However, 24 days later, the hippocampal animals manifest a profound deficit in the retention of the spatial information. When the spatial task learned during the acquisition phase requires only the use of a guidance strategy, control and lesioned animals show the same level of performance during the training phase and the same degree of retention during the retraining phase 24 days after criterion. Taken together, these results suggest that the hippocampus plays a crucial role in long-term retention of allocentric spatial information.

Amnesia↗