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M Alvarez

Publications and source records attributed to M Alvarez.

At least 181 records · Page 10Linked to original sources
PubMed1997

[Primary cardiac lymphoma: presentation of a case and review of the literature].

We describe a case of primary cardiac lymphoma presenting with chest pain, complete AV block, negative T waves, and infiltration of the basal segments and right free ventricular wall on echocardiography, interpreted initially as hypertrophy. One month later the patient was readmitted with systemic disease and cardiac insufficiency. Furthermore multicentric myocardial infiltration with a nodular mass in the right atrium producing severe tricuspid stenosis was demonstrated. Surgical biopsy was performed and a high grade non-Hodgkin's lymphoma diagnosed. The patient died during the immediate post-operative period without receiving specific chemotherapeutic treatment. Reviewing the published cases, we found that primary cardiac lymphomas are fast growing tumors that infiltrate predominantly the right cavities and have limited therapeutic options.

Fatal Outcome↗
PubMed1997

Group B streptococcal meningitis in adults: report of twelve cases and review.

Group B streptococcus (GBS) is the leading etiologic agent of bacterial meningitis and sepsis during the neonatal period, but it is an infrequent cause of meningitis in adults. We report 12 episodes of group B streptococcal meningitis in adults and review 52 cases reported in the literature. A total of 24 men and 40 women were included in the study; the mean age (+/- SD) was 49.2 +/- 20.5 years (range, 17-89 years). All the patients had cerebrospinal fluid cultures positive for GBS. Eighty-six percent of the patients had comorbid conditions, 50% had a distant focus of infection, and blood cultures yielded GBS for 78.7%. The overall case-fatality rate was 34.4% (22 patients). Factors associated with a poor outcome were advanced mean age (+/- SD) (61.5 +/- 17.4 years vs. 42.8 +/- 19.2 years; P = .0003) and the presence of complications on admission (P = .0001). Seven percent of survivors had neurological sequelae. Group B streptococcal meningitis in adults has become increasingly frequent in recent years; it tends to occur in patients with severe underlying conditions and is associated with a high case-fatality rate. Factors associated with a poor prognosis are advanced age and the occurrence of neurological and extraneurological complications.

Adult↗
PubMed1997

Monoclonal antibodies raised to the dengue-2 virus (Cuban: A15 strain) which recognize viral structural proteins.

Mouse monoclonal antibodies (MAbs) were raised to dengue-2 virus (D-2V) Cuban (A15) strain and the cell culture supernatants were screened by ELISA using the homologous virus. Three MAb-secreting lines were further characterized using immunoblot, haemaglutination, complement-fixation, and neutralization assays. One of these, MAb 8H8, weakly reacted with the viral nonstructural-1 protein (NS1) but more specifically identified the capsid protein (C), MAb 3E1 recognized in serological assays D-2V A15 but it had a weak reaction to C protein by immunodetection whereas another, MAb 4G3, weakly neutralized the homologous virus isolate and blocked the binding of specific anti-envelope (E) Mab, and its reaction with this protein could not be confirmed using immunoblot assays. These reagents are now being used to compare virulent plus avirulent Caribbean viruses antibody dependent enhancement (ADE) assays.

Animals↗
PubMed1997

Value of single oral loading dose of propafenone in converting recent-onset atrial fibrillation. Results of a randomized, double-blind, controlled study.

AIMS: To evaluate the efficacy and safety of a single loading oral dose of propafenone in the interruption of recent-onset atrial fibrillation. METHODS: After a complete medical history, physical examination, 12-lead ECG, chest X-ray, and routine biochemical laboratory testing, 55 consecutive patients with recent-onset atrial fibrillation were randomized double-blind in the emergency department for the administration of either a single oral dose (450 to 750 mg) of propafenone (29 cases) or a placebo (26 cases). After the 24-h observation period, comprehensive echocardiographic examination was performed. RESULTS: The groups were homogeneous as regards biological, clinical and echocardiographic characteristics. Two hours after treatment, 12 patients (41%) on propafenone but only two (8%) on placebo had converted to sinus rhythm (P = 0.005). This striking difference was maintained 6 h after treatment (65 vs 31%; P = 0.015) but lessened at 12 h (69% vs 42%; P = 0.060) and was insignificant at the end of the 24-h treatment period (79%, vs 73%; P = 0.752). Apart from hypotension, transient in three cases and sustained in one whose later echocardiographic examination demonstrated left systolic ventricular dysfunction, propafenone was well tolerated. CONCLUSION: Although there is no significant difference in the rates of conversion 24 h after treatment, propafenone works faster than placebo in achieving sinus rhythm. This rapid action of oral propafenone can be useful to solve quickly the clinical problems of a high proportion of patients arriving at the emergency department with acute atrial fibrillation.

Acute Disease↗
PubMed1997

Deep infections caused by Scedosporium prolificans. A report on 16 cases in Spain and a review of the literature. Scedosporium Prolificans Spanish Study Group.

Scedosporium prolificans, a mold morphologically similar to Scedosporium apiospermum, may cause asymptomatic colonization or localized or disseminated infection following trauma, surgery, and immunosuppression. S. prolificans is normally resistant to available antifungal agents, and prognosis depends largely on the host's immune status, extent of infection, and feasibility of surgical debridement. We report on 16 patients with deep S. prolificans infections, focusing on predisposing factors, clinical characteristics, outcome, postmortem findings, and antifungal susceptibility testing to 6 antifungal agents. Between 1989 and 1994, 16 cases of deep infections by S. prolificans were documented in 6 clinical centers in Spain (15 adults and 1 child: male/female = 0.77). Fifteen patients had underlying hematologic malignancy (14 with neutropenia) and 1 had a prosthetic cardiac valve. Syndromes included disseminated infection in 14 patients (1 with prosthetic valve endocarditis) and fungal pneumonia and meningoencephalitis in 1 patient each. S. prolificans was isolated from 2 specimens in 14 patients and from 1 specimen in 2 patients (blood, n = 12; respiratory tract, n = 4; CNS, n = 4; and skin biopsy, n = 3). Antifungal susceptibility testing by a micromethod with RPMI-2% glucose medium was performed in 8 isolates, all of which were resistant to amphotericin B, flucytosine, ketoconazole, fluconazole, itraconazole, and miconazole. All patients received antifungal therapy (amphotericin B, n = 9; amphotericin B+ flucytosine, n = 1; amphotericin B+ itraconazole, n = 2; liposomal amphotericin B+ itraconazole, n = 1; amphotericin B+ fluconazole, n = 1 and 2 underwent surgical procedures. Two patients survived coinciding with hematologic recovery and 14 (87.5%) patients died in a median time of 4 days after the first positive culture (range, 0-60 d). Necropsy was performed in 10 patients, and disseminated infection was found in 9. In conclusion, S. prolificans is an emerging multiresistant fungal pathogen that may cause asymptomatic colonization, localized infection related to trauma or surgery, and rapidly fatal disseminated infection in immunocompromised hosts, particularly those with neutropenia. This mycosis underscores the urgent need for new antifungal agents.

Adolescent↗
PubMed1997

Complete nucleotide sequence of the HLA-DRB1 *1302 allele.

Sequencing studies of HLA class II molecules have focused almost exclusively on its exon 2. The complete cDNA sequence of the DRB*1302 allele is reported here for the first time. A conservative polymorphism was detected outside the exon 2 at residue 206; these changes can only be recorded if complete cDNA sequences are studied, and may be of value in drawing evolutive inferences.

Base Sequence↗
PubMed1997

High polymorphism of Mhc-E locus in non-human primates: alleles with identical exon 2 and 3 are found in two different species.

Thirteen Mhc-E new sequences were found in eight individuals belonging to the Cercopithecinae family, i.e.: Macaca mulatta, Macaca fascicularis and Cercopithecus aethiops when studying E locus polymorphism. No changes were found in the invariant residues which are required for the correct conformation of the peptide presenting region which are conserved in classical Mhc class I molecules from fish and reptiles to humans; however, polymorphism of Mhc-E alleles is not limited to the three typical hypervariable regions per domain as it is in classical class I alleles. The rate of synonymous and nonsynonymous substitutions in the DNA sequence corresponding to the antigen binding site, compared to the remainder of exons 2 and 3 shows that the peptide-binding site is under high evolutionary pressure for stability since only synonymous substitutions have been found to be accepted in apes. Also, a clear example of trans-species evolution of allelism is found: two identical exon 2 and exon 3 sequences there exist belonging to individuals from different species (Mamu-Mhc-E*0101 and Mafa-Mhc-E*04). In addition, two Macaca mulatta individuals show an Mhc-E locus duplication. Finally, phylogenetic tree analysis shows that Mhc class I molecules found in Saguinus oedipus (described as Mhc-G homologues) are closer to Mhc-E sequences.

Alleles↗
PubMed1997

Mhc-E polymorphism in Pongidae primates: the same allele is found in two different species.

Mhc-E intron 1, exon 2, intron 2, and exon 3 from pygmy chimpanzee (Pan paniscus), chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla) and orangutan (Pongo pygmaeus) have been sequenced; six new Mhc-E alleles have been obtained but sequence changes are only placed either in introns or in synonymous exonic bases. One pygmy chimpanzee Mhc-E DNA sequence is identical to another sequence from chimpanzee; the fact that no variation is found also at the intronic level suggests that these two species of chimpanzee may have recently separated and/or that both of them might only represent subspecies. Mhc-E phylogenetic trees separate two evolutionary groups: Pongidae, including humans, and Cercopithecinae; this is also found by studying another non-classical class I gene, Mhc-G. The Mhc-E alleles' invariance at the protein level supports that strong selective forces are operating at the Mhc-E locus, as has also been found in both Cercopithecinae and humans. These allelic and evolutionary data suggest an altogether different functionality for HLA-E (and also HLA-G) compared with classical class I proteins: i.e., sending negative (tolerogenic) signals to NK and T cells.

Alleles↗
PubMed1997

Molecular tracking of Candida albicans in a neonatal intensive care unit: long-term colonizations versus catheter-related infections.

Nosocomial neonatal candidiasis is a major problem in infants requiring intensive therapy. The subjects of this retrospective study were nine preterm infants admitted to the neonatal intensive care unit of the Hospital Central de Asturias between March 1993 and August 1994. The infants were infected with or colonized by Candida albicans. Five patients developed C. albicans bloodstream infections. A total of 36 isolates (including isolates from catheters and parenteral nutrition) were examined for molecular relatedness by PCR fingerprinting and restriction fragment length polymorphism (RFLP) analysis. The core sequence of phage M13 was used as a single primer in the PCR-based fingerprinting procedure, and RFLP analysis was performed with C. albicans-specific DNA probe 27A. Both techniques were evaluated with a panel of eight C. albicans reference strains, and each technique showed eight different patterns. With the 36 isolates from neonates, each technique enabled us to identify by PCR and RFLP analysis seven and six different patterns, respectively. The combination of these two methods (composite DNA type) identified eight different profiles. A strain with one of these profiles was present in three patients and in their respective catheters. Patients infected with or colonized by this isolate profile were clustered in time. Among the other patients, each patient was infected over time and at multiple anatomic sites with a C. albicans strain with a distinct DNA type. We conclude that C. albicans was most commonly producing long-term colonizations, although horizontal transmission probably due to catheters also occurred.

Base Sequence↗
PubMed1997

Efficacy and safety of two new methods of rapid intravenous detoxification in heroin addicts previously treated without success.

BACKGROUND: New methods of rapid opiate detoxification, under intravenous sedation, can detoxify heroin-addicted patients in 24 hours. Their clinical application has been limited by the lack of studies establishing both efficacy and safety. METHOD: In a randomised, controlled study, 300 treatment-refractory, heroin-addicted patients received rapid intravenous detoxification treatment (naloxone infusion, 0.06-0.08 mg/kg, then oral naltrexone 50 mg/day) under either monitored light intravenous sedation or unmonitored deep intravenous sedation. RESULTS: All patients were successfully detoxified and 93% remained abstinent one month later. Severity of withdrawal, according to the Wang Scale modified by Loimer, was 4.9 (s.d. 3.0) points in the light sedation group and 4.8 (s.d. 2.9) in the deep sedation group (P = 0.26). Two patients (1.3%) in the light sedation group and four (2.6%) in the deep sedation group required tracheal intubation (P = 0.31). There was only one severe complication, a case of nosocomial aspirative pneumonia which improved with antibiotic treatment. CONCLUSIONS: Successful rapid intravenous detoxification can be achieved using relatively light levels of sedation.

Adult↗
PubMed1997

Rat osteoblast and osteosarcoma nuclear matrix proteins bind with sequence specificity to the rat type I collagen promoter.

The nuclear matrix mediates the 3-dimensional organization of DNA and supports DNA replication and its transcription. We hypothesize that the osteoblast nuclear matrix contributes to the transcriptional control of type I collagen (COL1A1) expression. Cis-regulatory elements of the rat COL1A1 promoter that control osteoblast expression in vivo are between -2.3 and -1.67 kilobase pairs (kb) but lie within -3.5 and -2.3 kb in cultured bone cells. This may result from differences in cell architecture between osteoblasts in tissue and those in vitro. Our aim was to identify osteoblast nuclear matrix proteins (NMPs) that associated with sequence-specificity to the COL1A1 promoter. We used osteoblasts from the rat metaphyseal femur and the rat osteosarcoma cells, ROS 17/2.8. Nuclear matrix and soluble nuclear proteins were obtained as separate subfractions. Gel mobility shift analysis, using fragments of the COL1A1 promoter, was used to identify DNA-binding proteins in the nuclear subfractions. A NMP-DNA interaction, NMP3, was observed between -2149 and -2106 nucleotide in both osteoblasts and osteosarcoma cells. NMP4 was detected between -3518 to -3406 nucleotide. Therefore, osteoblast NMPs recognize sequences in regulatory regions of the COL1A1 promoter and may link cell structure and the transcriptional regulation of this protein.

Animals↗
PubMed1997

Attentional functioning in children and adolescents with IDDM.

OBJECTIVE: To determine whether specific attentional cognitive processes are disrupted in children and adolescents with IDDM. RESEARCH DESIGN AND METHODS: We tested 103 children and adolescents with IDDM and 100 healthy control subjects (age range 9.3-18.3 years) for intelligence and attention. Subjects were given multiple clinical tests of attention and a computerized vigilance test, all of which served to provide information about multiple components of attentional processing. Specific components studied were the abilities to focus, select, shift, suppress, inhibit, and sustain attention. A diabetic history was obtained for the IDDM group, and blood glucose levels were determined before and after computerized attention testing. RESULTS: Across tests, IDDM subjects differed from control subjects only in the select component of attention, which was accounted for mainly by the poorer performance of children with early-onset diabetes (< 6 years). When subgrouped by history of seizures from hypoglycemia, those having had seizures demonstrated a lower verbal IQ and greater difficulty with select, focus, and inhibit attentional components, whereas sustain, suppress, and shift attentional components were unaffected. Correlation analyses showed that higher concurrent blood glucose levels were associated with less adequate ability to inhibit impulsive responses, whereas multiple regression analyses indicated that inhibit and focus were best predicted by onset age and concurrent blood glucose. CONCLUSIONS: In children and adolescents with IDDM, attention is poorer in several but not all aspects of attention; these aspects are affected by a history of seizures from hypoglycemia and higher ambient blood glucose levels at time of testing. These results suggest both organizational and activational effects of diabetes on specific subcomponents of attention in diabetes.

Adolescent↗
PubMed1997

[Usefulness of the angiographic examination of the left internal mammary artery in patients candidates for coronary bypass surgery].

BACKGROUND AND OBJECTIVE: The usefulness of preoperative angiographic evaluation of the internal mammary artery (IMA) is controversial. The aim of this study is to evaluate the problem by a basic cost-benefit analysis. METHODS: One hundred and twenty-one patients whose coronary findings (left main disease and/or severe stenosis of the left anterior descending artery) made use of the IMA as a bypass graft a consideration were studied. The IMA was cannulated by the same right Judkins catheter used in the coronarography; the specific catheter was only used if the cannulation was not successful with the right Judkins. We measured the time it took for a good angiography of the IMA to be obtained; the anatomy and the size for each IMA were studied and compared with the size of the left anterior descending artery. RESULTS: An optimal angiographic picture of the IMA was obtained in 119 cases (98.3%); a specific catheter was used only in 3 patients. The mean of the time employed was 170 seconds (8-900 s) and no complications were related to IMA cannulations. Angiography findings relevant to any planned surgery were demonstrated in 15 patients (12%): large proximal branches (10); occlusion stenosis or a caliber insufficient for IMA (3); and occlusion or proximal subclavian stenosis (2). CONCLUSIONS: We have observed that the relation between the cost and the obtained information is adequate to warrant its performance, because angiographic findings relevant to planned surgery can be very important, even though they are fairly infrequent. Moreover, these findings can be achieved rapidly without additional cost.

Coronary Angiography↗
PubMed1997

Viral isolation from cases of epidemic neuropathy in Cuba.

OBJECTIVE: To investigate the possibility of a viral agent in the central nervous system of patients with epidemic neuropathy. DESIGN: Virus isolation attempts, in cell cultures and suckling mice, from cerebrospinal fluid (CSF) of neuropathy patients and controls undergoing lumbar puncture for unrelated reasons. Serologic studies in patients, contacts, and controls. SETTING: An epidemic of optic and peripheral neuropathy affected more than 50,000 people in Cuba in 1991 through 1993. Illness was associated with dietary limitations and increased physical demands accompanying the shortages of food and fuel experienced in Cuba since 1989. Most patients responded to parenteral vitamin therapy, and the epidemic began to subside when oral vitamin supplementation was begun for the entire Cuban population. RESULTS: Coxsackievirus A9 (five isolates) and a similar, less cytopathic virus (100 isolates) were recovered from 105 (84%) of 125 CSF specimens from neuropathy patients. The strains with light cytopathic effect were antigenically related to Coxsackieviruses A9 and B4 by cross-neutralization and immunoblotting assays. Virus persisted in CSF of some patients for 1 to 12 months. Cerebrospinal fluid from patients and both types of virus from cell culture produced illness, including complete posterior flaccid paralysis, in newborn mice, and virus was reisolated from the mice. Mouse tissues and sural nerve biopsy specimens from patients were stained by immunoperoxidase and colloidal gold techniques using hyperimmune rabbit antisera against the virus with light cytopathic effect. CONCLUSIONS: Coxsackievirus A9 or an antigenically related agent with a light cytopathic effect was present in CSF of 84% of 125 patients with epidemic neuropathy. The role of these agents, probably in combination with nutritional factors, in the pathophysiology of the disease requires further investigation.

Adult↗
PubMed1997

Proliferative and maturative behaviour patterns on murine bone marrow and spleen erythropoiesis along hypoxia.

The present study was performed to determine quantitative and qualitative effects of hypoxia on murine erythron. CF1 mice were submitted to hypobaric hypoxia (HH) along 18 days. The proliferative response to recombinant human erythropoietin (rHuEPO: 0-250 mU/ml) was analyzed by DNA assays from bone marrow and spleen cells at different times. Bone marrow proliferative response showed a slight increment under stress but remained over control by the end of the experience. Splenic erythroid proliferative response was observed at a maximum rate on day 6 of HH (26 fold) and returned near to control values after day 10. The assessment of erythropoietic maturative pattern was performed by 59Fe uptake assays. Total nuclear cell counts increased in both tissues (1.5 times in marrow and 5 times in spleen) under hypoxia. In addition, percentages of different lineages (erythroid, myeloid and lymphoid) were scored. Total erythroid marrow cell counts increased in a narrowly degree and persisted above basal counts after day 18. Meanwhile, splenic red cells rose to 30 times over control on day 6 and failed sharply near control values from day 12 of HH. Splenic red cells contribution was approximately 60% of total production between 6-8 days. By the end of the assay bone marrow took back erythroid command (90%). These findings indicate correlation between the time course as well as quantitative and qualitative parameters in the patterns of proliferation and maturation. Moreover, the erythron response to hypoxia, seemed to be related to microenvironmental regulations rather than to hormonal variances.

Animals↗
PubMed1997

[in vitro activity of carbapenems against Enterobacteriaceae and Pseudomonas aeruginosa hyperproducers of group 1 chromosomal beta-lactamases].

Resistance to imipenem and meropenem, reported sporadically in Enterobacteriaceae and more frequently in Pseudomonas aeruginosa, can be caused, among other mechanisms, by the combination of changes in permeability and hyperproduction of inducible chromosomal beta-lactamases. In this study, the in vitro activity of imipenem and meropenem was analysed by the agar dilution method against cefotaxime, ceftazidime, and aztreonam resistant clinical strains of Enterobacteriaceae (n = 202) and P. aeruginosa (n = 90). This phenotype is consistent with the hyperproduction of group 1 chromosomal beta-lactamases and was previously determined in stably derepressed mutants in the same species, obtained from strains with inducible beta-lactamase expression by selection with cefotaxime and ceftazidime. Likewise, the activity of imipenem and meropenem against the same number of clinical isolates susceptible to cefotaxime, ceftazidime, and aztreonam was evaluated. In general, imipenem and meropenem showed an excellent activity, which was intrinsically greater for meropenem against Enterobacteriaceae and P. aeruginosa organisms. Nevertheless, imipenem and meropenem activity was slightly affected on cefotaxime, ceftazidime, and aztreonam resistant isolates of E. cloacae (MIC90, 1 and 0.2 microgram/ml, respectively), E. aerogenes (1 and 0.2 microgram/ml), C. freundii (1 and 0.1 microgram/ml), M. morganii (1 and 0.5 microgram/ml), and S. marcescens (4 and 0.5 micrograms/ml). On the other hand, the activity of imipenem and meropenem against ceftazidime and aztreonam resistant isolates of P. aeruginosa was more significantly affected, with MIC90 values of 64 and 16 micrograms/ml, respectively.

Enterobacteriaceae↗