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Biomedical subjects

F García

Publications and source records attributed to F García.

At least 19 recordsLinked to original sources
PubMed1995

Brain distribution of c-fos expression as a result of prolonged rapid eye movement (REM) sleep period duration.

Auditory stimulation (AS) or recovery from sleep deprivation (SD) has been shown to increase REM sleep periods in rats, cats and humans. This increment in REM has been credited to an amplified level of excitability in a widely distributed neuronal network throughout the brain. Fos-like immunostaining (FLI) has been useful in constructing maps of post-synaptic neuronal activity with single cell resolution, and has been proposed to be tightly related with progressing neuronal activation. This study utilized FLI as a marker to determine the number of neurons and structures which express c-fos in broadly distributed areas of the brain in animals with REM periods prolonged by either AS or SD. The results indicated that the brain stem and diencephalon present FLI increases in a variety of structures that possibly share various functional aspects of the REM sleep mechanism. These results are discussed in terms of the possibility that REM maintenance is related to an increase in the recruitment of REM-on neurons.

Acoustic Stimulation↗
PubMed1995

Modulation of peptide binding by HLA-B27 polymorphism in pockets A and B, and peptide specificity of B*2703.

The results in this study address three aspects of peptide binding to the disease-associated antigen HLA-B27 and its modulation by polymorphism: the contribution of major anchor residues 2 and 9, the role of pocket B polymorphism in modulating peptide specificity, and the binding properties of B*2703, a subtype not found to be associated with spondyloarthropathy. Synthetic analogs of peptides naturally presented by B*2705 were used to demonstrate that residue 2 is essential, since Ala2 analogs bound marginally to B*2705, but the specificity of B*2705 for Arg2 is not absolute, and show that the contribution of basic residue 9 to binding was significant, but less than Arg2. The effect of single mutations in the B pocket was to decrease or--with the Glu > Met-45 mutation--totally shift pocket B specificity for Arg2 towards other residues at this position. This was shown by quantitating the relative binding of Gln2 and Ala2 analogs, and by pool-sequencing of the peptides bound in vivo to these mutants. Peptides naturally presented by B*2705 apparently bound with a lower affinity to pocket A variants with altered hydrogen bonding to the peptide N terminus, including B*2703. Binding of peptide analogs with changes at positions 2 or 9 suggested that in B*2703 pocket A, interactions are weaker and pocket B interactions are stronger than in B*2705. This can be explained by the effect of the unique His59 change in B*2703 in both pockets. Thus, B*2703 is probably the HLA-B27 sub-type with the most stringent specificity for the Arg2 peptide motif.

Amino Acid Sequence↗
PubMed1995

Human immunodeficiency virus type-1 can be detected in monocytes by polymerase chain reaction.

Lymphocytes and monocytes from 25 patients infected with human immunodeficiency virus type-1 (HIV-1)--13 asymptomatic, seven with the AIDS-related complex (ARC) and five with the acquired immunodeficiency syndrome (AIDS)--were lysed and subjected to PCR with three primer pairs: SK38/SK39 (gag), SK68/SK69 (env) and SK29/SK30 (LTR). Amplified DNA was solution-hybridised with 32P-labelled probes (SK19, SK70 and SK31, respectively) and detected by PAGE-autoradiography. HIV-1 DNA was detected as follows. Asymptomatic patients: monocytes--gag 61.5%, env 100%, LTR 0%; lymphocytes--gag 100%, env 92.3%, LTR 53.84%. ARC patients: monocytes--gag 71.4%, env 57.1%, LTR 0%; lymphocytes--gag 100%, env 71.4%, LTR 71.4%. AIDS patients: monocytes--gag 80.0%, env 100%, LTR 0%; lymphocytes--gag 100%, env 60%, LTR 60%. The presence of HIV-1 DNA was confirmed in the monocyte fraction. In this cell subset, the env gene-directed primers were the most effective for amplification, whereas the LTR gene-directed primers failed to amplify HIV-1 DNA. The different pattern of amplification found in monocytes may suggest that these cells could be infected by a genetic variant of the virus.

AIDS-Related Complex↗
PubMed1995

Cephalosporin binding sites to human serum albumin and the relation with the N-B transition of this protein.

The binding of some cephalosporins to human serum albumin was studied using probes for the so-called I, II, bilirubin and fatty acids binding sites. The results showed that cephradine and cefsulodin bind to site II, cefaclor, cefamandole, cefsulodin, cephaloglycin and cefadroxil bind to the bilirubin binding site, while cefaclor does it to the fatty acid binding site. No binding of these cephalosporins to site I of albumin was found. The binding produced a perturbation on the N-B equilibrium of albumin, stabilizing the N conformational form, which suggests that the N form of albumin has more affinity with the cephalosporins than the B form. This finding gives support to the assumption that the binding of cephalosporins to site II, bilirubin and fatty acids binding sites affects the N-B transition of albumin.

Bilirubin↗
PubMed1995

[Spondylodiscitis caused by Enterococcus: an unusual entity].

BACKGROUND: Spondylodiscitis by enterococcus is a very infrequent disease with only 2 cases caused exclusively by this microorganism having been reported in the literature. METHODS: Two clinical cases of spondylodiscitis by enterococcus diagnosed in the authors' department are presented with the clinical, radiologic and evolutive features of both. RESULTS: In the first case the spondylodiscitis was secondary to endocarditis with lumbosacral involvement and formation of an anterior epidural inflammatory mass. The second case was the consequence of an infection of urinary origin with lumbosacral involvement. Both patients responded favorably with only antibiotic treatment. CONCLUSIONS: Spondylodiscitis by enterococci is an unusual disease with no therapeutic experience. The authors report 2 cases which were treated exclusively with antibiotics.

Aged↗
PubMed1994

T cell allorecognition and endogenous HLA-B27-bound peptides in a cell line with defective HLA-B27-restricted antigen presentation.

The B*2702+ lymphoblastoid cell line NW is unable to present at least some HLA-B27-restricted viral antigens to T cells. This defect was genetically inherited, and was suggested to be related to the nature of the HLA-B27 binding peptides reaching the endoplasmic reticulum in these cells (Pazmany et al., J. Exp. Med. 1992. 175: 361). In the present study 17 of 19 HLA-B27-specific alloreactive cytotoxic T lymphocyte clones recognizing the B*2702 subtype on other cells also lysed NW cells. Only two cytotoxic T lymphocyte clones failed to lyse NW while efficiently killing other B*2702+ cell lines. The high-performance liquid chromatography profiles of the B*2702+ bound peptides extracted from NW cells was similar, but not identical, to those from two other cell lines. These results indicate that the HLA-B27-bound peptide repertoire in NW cells is not fundamentally different from those in other B*2702+ cells. Our data argue against gross differences in peptide processing or transport as being responsible for the defective presentation of particular HLA-B27-restricted viral antigens to T cells, but do not rule out distinct presentation of some endogenous peptides. Differences in the capacity to present certain peptides could cause differential susceptibility among HLA-B27+ individuals to ankylosing spondylitis.

Antibodies, Monoclonal↗
PubMed1994

Structure of HLA-B27-specific T cell epitopes. Antigen presentation in B*2703 is limited mostly to a subset of the antigenic determinants on B*2705.

The structure of HLA-B27-specific epitopes recognized by anti-B*2705 and anti-B*2703 cytotoxic T lymphocytes (CTL) from three unrelated donors was examined with site-specific mutants at various side-chain pockets in the antigen-binding site. The effect of any given mutation on allorecognition correlated strongly with its predictable effect on peptide binding. Acidic charges in the C/F pocket of HLA-B27, which binds C-terminal peptide residues, strongly modulated allorecognition. Anti-B*2705 CTL from different donors were differently affected by some mutations, indicating individual differences in the structure of epitopes recognized by alloreactive CTL from each donor. Most anti-B*2703 CTL recognized a subset of epitopes that were also present on B*2705, but differed from the bulk of allospecific epitopes on this subtype in their smaller dependence on pocket A structure, where the difference between these subtypes is located, and in their greater dependence on Glu45, in the B pocket. The structure of the very few epitopes on B*2703 not shared by B*2705 was quite different from that of the much more predominant cross-reactive epitopes. The results strongly suggest that B*2703 is antigenically defective as compared with B*2705 and that this is due to the fact that the repertoire of peptides presented by B*2703 consists mainly of a subset of the B*2705-bound peptides which do not critically require the canonic binding of the peptidic N-terminus to a B*2705-like A pocket, because they are sufficiently stabilized by other contacts through the peptide binding site.

Antigen-Presenting Cells↗
PubMed1994

Histological study in contralateral testis of prepubertal children following unilateral testicular torsion.

Histological changes in the contralateral testis in 8 prepubertal children whose ages ranged from 3 to 7.5 years with a history of testicular torsion and subsequent atrophy were studied. The following histological parameters were evaluated: fertility tubular index (FTI), Sertoli cell index (SCI) and minimum tubular diameter (MTD). According to our findings and following Nistal and Paniagua's classification (1984) for tubular alterations, we found 5 cases (62.5%) who present the following alterations. Type 1 (case 2): FTI was decreased above 50% corresponding to slight germinal hypoplasia with normal MTD and SCI. Type 2 (cases 3 and 5): testis with remarkable germinal hypoplasia; FTI was between 30 and 50% while MTD was below normal values. Type 3 (case 8): testis with diffuse tubular hypoplasia; FTI was below 30%, whereas MTD showed 33% decrease regarding normal values. Type 4 (case 6): testes with hyperplasia of Sertoli cells; SCI was increased one third with regard to that corresponding to his age; FTI showed severe hypoplasia of germ cells. No relationship between alterations in either the age of the patients or the time elapsed since the torsion was observed. Because of all these facts and the young age of our patients, we believe that the alterations found in the contralateral testis were due to congenital dysgenesia.

Atrophy↗
PubMed1994

[High prevalence of hepatitis B and C markers in an indigent community in Caracas, Venezuela].

Hepatitis B and C serological markers were evaluated in indigent patients living in a workhouse in Caracas, Venezuela. Three out of 146 specimens were reactive for HBsAg (2.1%) and 41 for anti-HBc (28%). Eight sera were reactive for antibodies against HCV, and 7 were confirmed by immunoblot assays (4.8%). Four out of these 7 HCV-positive sera were also HCV-RNA positive. The prevalence for viral hepatitis markers was significantly higher than that found in blood donor population in Caracas. The probable risk factors associated with this high prevalence of blood-borne viral hepatitis were: promiscuity, transfusion, drug addiction, alcoholism and history of reclusion. This high prevalence of hepatitis B and C compels the precaution for medical and paramedical staff attending this kind of patients.

Adult↗
PubMed1994

Nasal CPAP during wakefulness increases intraocular pressure in glaucoma.

Few important side-effects of nasal continuous positive airway pressure (nCPAP) have been reported. No increase of intraocular pressure (IOP) complicating this treatment has previously been described. The goal of our study was to analyse the influence of nCPAP on IOP. We evaluated 18 patients previously diagnosed as having glaucoma and 22 normal subjects. nCPAP was used during wakefulness, at +12 cmH2O for 15 min. The results showed that nCPAP significantly increases IOP in patients with glaucoma (before nCPAP 20.3 +/- 6.3 mmHg) (mean +/- SEM); after nCPAP 22.3 +/- 5.7 mmHg. We believe that nCPAP might be relatively contraindicated in difficult to manage glaucoma patients, if these results are corroborated.

Female↗
PubMed1994

[Imported acute hepatitis in Spanish travelers to tropical countries].

Among the immunizable diseases, viral hepatitis is the most frequently diagnosed in travellers. The epidemiology and the clinical presentation of the imported viral hepatitis among patients in the Tropical Medicine Unit of Hospital Clínic (Barcelona) are studied in this article. A retrospective review of 47 viral hepatitis in Spanish travellers seen during the period 1988-1991 is presented, representing 2.47% of all diagnosis. Only a third of the patients were hepatitis A cases. The duration of the trip was significantly shorter in those who acquired hepatitis of the A and non-A--non-B types. Africa (60% cases), India and South East Asia (17%) and Central America (16%) were considered areas of risk. The B, C and non-A--non-B hepatitis types had a more silent clinical and biological presentation. Gathered data confirm the importance of hepatitis as an imported disease, the partial protection of the Spanish population against hepatitis A and the need to introduce this infection among the advice to be given in a travellers clinic.

Acute Disease↗
PubMed1994

Factors that influence the outcome of the intrauterine insemination with husband's sperm.

A retrospective analysis was undertaken in 160 intrauterine insemination with husband's sperm (IUIH) cycles, performed in 45 couples. The male factor represented the main indication (80%). Women who conceived had a lower duration of infertility (4.4 years +/- 3.0 vs 7.7 +/- 2.98). A significantly and pardoxically lower motility (3+ and 2+) was observed in raw specimens within conceptional cycles. However in prepared specimens in conceptional cycles the percentage of motility 3+ and 2+ was significantly increased (80.6% +/- 8.1 versus 70.7% +/- 20.2). The most significant difference was found in regard to a better response to preparation among conceptional cycles, expressed as the percentual increase in motility 3+ and 2+ (55.6% +/- 3.9 vs 41.3% +/- 19.4).

Adult↗
PubMed1993

[Prevalence of non-insulin dependent diabetes mellitus in Lejona (Vizcaya, Spain)].

BACKGROUND: Diabetes mellitus presents a high prevalence and morbimortality. The aim of the present study was to know the number of newly diagnosed diabetic patients in addition to those who present abnormal glucose tolerance and possible presence of associated risk factors. METHODS: This study was carried out in Lejona (Vizcaya) from 1984-1985. The prevalence of non insulin-dependent diabetes mellitus (NIDDM) and abnormal glucose tolerance (AGT) in people older than or equal to 30 years of age by a randomized sample stratified by pyramids of age and sex (n = 862). The following data were collected: age, sex, height, weight, medications taken, family and personal history of diabetes mellitus (DM) and blood pressure. A glycemia curve was made following the criteria recommended by the Committee of Experts of the World Health Organization (WHO). RESULTS: The prevalence of DM observed in the sample was of 6.4% (confidence interval of 95%: 4.75-8.01%) of which 3.6% corresponded to unknown DM and 2.8% to known DM. The prevalence of AGT was 10.4% (confidence interval 95%: 8.40-12.48%). Greater association was observed between DM and obesity, lower height, high blood pressure and age over 50. CONCLUSIONS: More than half of the diabetics were unaware of the disease. Given the association of non insulin-dependent diabetes mellitus with modifiable factors (obesity, high blood pressure) control of risk factors would be useful with the aim of decreasing the prevalence of diabetes mellitus and avoid the associated chronic complications of the disease.

Adult↗
PubMed1993

Effects of different factors in lead- and cadmium-induced hypothermia in mice.

The aim of this study was to investigate the relationship between the hypothermic effect induced by lead or cadmium chloride treatments and the cerebral metal levels attained. Mice were injected intraperitoneally with different doses of lead acetate or cadmium chloride at ambient temperatures of 22 degrees C and 35 degrees C, and rectal temperatures and brain metal levels were determined. At 22 degrees C, doses of lead acetate exceeding 25 mg/kg caused significant hypothermia and a rise of lead levels in the brain; this hypothermic effect was significantly inhibited at 35 degrees C. In mice repeatedly treated with 2 or 5 mg/kg lead acetate and exposed to 22 degrees C or 35 degrees C, no significant changes were observed in body temperature after the repeated exposure, although brain lead levels increased significantly. Cadmium chloride at 22 degrees C produced a significant fall in body temperature, and a rise in brain cadmium levels at doses of 2-4 mg/kg; the decrease in body temperature was partially inhibited at 35 degrees C. The results of the present study suggest that the hypothermic effect elicited by these heavy metals is related to both the level of metal absorbed by the brain and its rate of uptake.

Animals↗
PubMed1993

Changes in the repertoire of peptides bound to HLA-B27 subtypes and to site-specific mutants inside and outside pocket B.

HLA-B27 subtypes share many structural features, including their pocket B, which interacts with a conserved Arg residue at the second position of B*2705-bound peptides. Subtypes differ among each other at other locations in the peptide binding site. In this study, metabolic labeling and radiochemical pool sequencing were used to address the following issues: (a) presence of the Arg 2 (R2) motif among peptides bound to the various HLA-B27 subtypes; (b) influence of mutations inside and outside pocket B on this motif; and (c) the degree of similarity among the peptide pools bound to the various B27 subtypes. Sequencing of Arg-labeled peptide pools extracted from B*2701 to B*2706, and from two site-directed mutants of B*2705 with changes outside pocket B, indicated that all of these molecules bind peptides with Arg at position 2. Peptides from several mutants with changes altering the structure of pocket B, and from one mutant at the pocket B rim, also retained the R2 motif. However, this was absent in the peptide pool extracted from the M45 mutant, in which the negative charge of pocket B, conferred to HLA-B27 by Glu45, was canceled. These results indicate that alterations outside pocket B, and even disruption of the network of hydrogen bonds that stabilizes Arg binding in pocket B, do not impair binding of peptides bearing the R2 motif, but a nonconservative substitution at position 45 does. As a substantial fraction of anti-B*2705 cytotoxic T lymphocyte (CTL) clones crossreact with the M45 mutant (Villadangos, J., B. Galocha, D. López, V. Calvo, and J. A. López de Castro. 1992. J. Immunol. 149:505) this result suggest that determinant mimicry by nonidentical peptides may frequently account for unexpected CTL crossreactions. Metabolic labeling with various other amino acids and radiochemical sequencing revealed similarities, but also substantial differences, among the peptide pools from the various HLA-B27 subtypes. This strongly suggests that many peptides bind to multiple subtypes, but significant subsets of peptides bound to a given HLA-B27 subtype do not bind to other subtypes or do so with greatly altered efficiency. These results indicate the importance of polymorphism outside pocket B in modulating peptide binding to HLA-B27.

Amino Acid Sequence↗