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J Romero

Publications and source records attributed to J Romero.

At least 145 records · Page 8Linked to original sources
PubMed1996

Pregnancies after intracytoplasmic sperm injection with cryopreserved testicular spermatozoa.

In 25 patients (14 suffering from obstructive azoospermia, six from non-obstructive azoospermia, three from asthenoazoospermia and two from absence of ejaculation) spermatozoa were extracted from testicular biopsies. Intracytoplasmic sperm injection (ICSI) with fresh testicular spermatozoa was performed in 18 cases; spermatozoa in excess were cryopreserved in pills. No pregnancies were achieved. In the remaining seven patients, testicular spermatozoa were retrieved and cryopreserved during a diagnostic testicular biopsy. After thawing, sperm motility was assessed in 17 cases (68%), and 18 ICSI with cryopreserved testicular spermatozoa were performed. The mean two-pronuclear (2PN) fertilization rate was 59%, the mean cleavage rate was 92%, and six clinical pregnancies were achieved, all of them still ongoing (pregnancy rate 33%). A comparison of the results of ICSI carried out with fresh or cryopreserved testicular spermatozoa showed that the mean 2PN fertilization rates per cycle (53 compared with 55%), mean cleavage rates per cycle (99 compared with 96%) and embryo quality were not significantly different. In conclusion, cryopreservation of testicular spermatozoa is feasible, even in patients with non-obstructive azoospermia, and the results of ICSI with frozen-thawed testicular spermatozoa are similar to those obtained using fresh testicular spermatozoa. Cryopreservation of testicular spermatozoa may avoid repetition of testicular biopsies to retrieve spermatozoa for successive ICSI cycles in patients in whom the only source of motile spermatozoa is the testicle.

Adult↗
PubMed1996

Bacterial populations in samples of bioleached copper ore as revealed by analysis of DNA obtained before and after cultivation.

The composition of bacterial populations in copper bioleaching systems was investigated by analysis of DNA obtained either directly from ores or leaching solutions or after laboratory cultures. This analysis consisted of the characterization of the spacer regions between the 16 and 23S genes in the bacterial rRNA genetic loci after PCR amplification. The sizes of the spacer regions, amplified from DNAs obtained from samples, were compared with the sizes of those obtained from cultures of the main bacterial species isolated from bioleaching systems. This allowed a preliminary assessment of the bacterial species present in the samples. Identification of the bacteria was achieved by partial sequencing of the 16S rRNA genes adjacent to the spacer regions. The spacer regions observed in DNA from columns leached at different iron concentrations indicated the presence of a mixture of different bacteria. The spacer region corresponding to Thiobacillus ferrooxidans was the main product observed at high ferrous iron concentration. At low ferrous iron concentration, spacer regions of different lengths, corresponding to Thiobacillus thiooxidans and "Leptospirillum ferrooxidans" were observed. However, T. ferrooxidans appeared to predominate after culture of these samples in medium containing ferrous iron as energy source. Although some of these strains contained singular spacer regions, they belonged within previously described groups of T. ferrooxidans according to the nucleotide sequence of the neighbor 16S rRNA. These results illustrate the bacterial diversity in bioleaching systems and the selective pressure generated by different growth conditions.

Bacteria↗
PubMed1996

[Antithrombotic therapy in atrial fibrillation].

The known risk of embolic events in patients with recurrent or chronic atrial fibrillation makes it mandatory to recommend oral anticoagulation in patients with rheumatic mitral valve disease, specially mitral stenosis to maintain an INR between 2.0 and 3.0. If despite this treatment recurrent embolism occurs, the dose of oral anticoagulants should be increased (INR between 2.5 and 3.5) or dipyridamole (200 to 400 mg/day) or aspirin (160 to 320 mg/day) should be added to dicoumarinic drugs. In patients that must be cardioverted either electrically or pharmacologically and who have been on atrial fibrillation for more than 2 days, oral anticoagulation should be maintained for 3-4 weeks before cardioversion and for 3-4 weeks after regaining sinus rhythm. Transesophageal echocardiography may enable us to identify the group of patients with low risk for an immediate cardioversion. In patients under 60 years of age with atrial fibrillation and no evidence of associated cardiovascular abnormality (lone atrial fibrillation) the embolic risk is very low and antithrombotic therapy is probably not needed. In subjects over 60 years of age with a low risk profile (absence of previous stroke, heart failure or systemic hypertension) aspirin (300-325 mg a day) seems to offer sufficient protection against embolic events. In patients at a higher embolic risk (history of previous cerebral ischemic attacks, heart failure of left ventricular dysfunction, systemic hypertension) oral anticoagulation unless contraindicated, should be recommended (INR 2.0-3.0). The role of other antithrombotic agents such as ticlopidine or triflusal to prevent embolic events in patients with atrial fibrillation is unknown.

Atrial Fibrillation↗
PubMed1995

Time-course of the effects of anandamide, the putative endogenous cannabinoid receptor ligand, on extrapyramidal function.

We have recently described the dose-response effect of anandamide (AEA), the N-amide derivative of arachidonic acid that acts as an endogenous ligand for the cannabinoid receptor, on extrapyramidal function. The present study has been designed to examine the time-course of this effect. To this end, adult male rats were submitted to an acute i.p. injection of AEA, delta9-tetrahydrocannabinol (THC) or vehicle and examined at different times after drug administration. Animals were tested in an open-field test, then sacrificed and their striata used for analyses of dopaminergic indices. Results were as follows. The administration of AEA or THC produced the expected inhibition of motor behavior. Thus, the administration of AEA decreased the ambulation and the frequency of stereotypic movements (in particular, the number of rears) and increased the time spent by the rats in inactivity. These effects were evident at 10 and 30 min after the administration of the cannabinoid agonist, but mostly disappeared at 60 min. Interestingly, motor inhibition was observed again around 2 or 3 h after the administration of AEA. This was a small but persistent effect (decreased ambulation followed by increased inactivity), because it was observed until at least 6 h after AEA administration. The other cannabimimetic, THC, was always able of decreasing the ambulation and the frequency of rearing and grooming behavior, and of increasing the time spent in inactivity. This effect was usually something more marked than the effect of AEA, but the most characteristic fact was its persistence at all times studies, even at 6 h after administration. These motor disturbances were accompanied by changes in the activity of nigrostriatal dopaminergic neurons. Thus, the administration of AEA decreased the activity of tyrosine hydroxylase (TH) in the striatum at 10 and 30 min after treatment, suggesting a decreased nigrostriatal activity parallel to the motor deficit observed at these times. This was followed by an increase in TH activity and dopamine and L-3,4-dihydroxyphenylacetic acid contents at 60 min after treatment, which would likely reflect a compensatory stimulation of these neurons, whereas restoration of control values was found at 180 min after AEA administration, suggesting that the motor deficit observed at this time was not dependent on dopaminergic influence. Paradoxically, the administration of THC only produced changes in dopaminergic activity at 60 min after treatment, similar to those seen with AEA, but was ineffective at the other times. In summary, A-EA inhibits motor behavior in parallel to reductions in the activity of nigrostriatal dopaminergic neurons. However, this effect was of short duration, disappearing at 60 min after treatment, as compared with the inhibitory effect of THC on motor behavior which was observed at all times studied. Interestingly, a new AEA-induced inhibition of motor behavior, which was not accompanied by dopaminergic changes, appeared at longer times although its meaning remains to be determined.

Animals↗
PubMed1995

De novo generation of defective interfering-like RNAs in broad bean mottle bromovirus.

Broad been mottle virus (BBMV) is the only member of the bromoviruses that is known to accumulate defective-interfering (DI) RNAs (Romero et al., Virology 194, 576-584, 1993). De novo generation of DI-like RNAs was demonstrated during serial passages of BBMV in broad bean using either DI RNA-free virion RNA preparations or transcribed genomic RNA inocula. As for previously described DI RNAs, all but one of the characterized de novo generated DI-like RNAs were derived by a single in-frame deletion from the RNA2 component. The sole exception was derived by two shorter in-frame deletions from RNA2. The maintenance of an open reading frame by all DI-like RNAs suggests the importance of coding capacity and/or the shortened 2a protein in the accumulation of these RNAs during infection. The deletion junction sites were between nucleotides 1152 and 2366, suggesting that the retained regions are essential for the efficient accumulation of BBMV DI-like RNAs in planta. Short regions of sequence similarity and/or complementarity were revealed at the 5' and 3' junction borders. We speculate that these regions can facilitate DI (DI-like) RNA formation. In addition to DI-like RNAs, the full-length nucleotide sequences of RNA2 components of the Type and Morocco strains of BBMV are presented.

Amino Acid Sequence↗
PubMed1995

Modulation of cellular chemoresistance in keratinocytes by activation of different oncogenes.

Response to chemotherapeutic agents in malignant tumors depends on many factors, most of which are as yet unknown. We investigated the correlation between the activation of different oncogenes and protein-kinase-C (PKC) modulation, and the cytotoxicity of some of the most widely used anti-cancer drugs. We transformed the murine keratinocyte cell line PAM 212, with different oncogenes (v-H-ras, v-myc and adenovirus E1a) and a mutant p53 suppressor gene (mp53). The cytotoxic effect of cisplatin (CDDP), doxorubicin (DOX) and vincristine (VCR), together with the concomitant action of modulators of PKC, TPA and staurosporine were evaluated by the crystal-violet method, thymidine incorporation and flow cytometry. We report that (a) the oncogene v-H-ras induces resistance to CDDP (> 50%), DOX (> 25%) and VCR (> 20%); (b) the E1a oncogene induces only resistance to VCR (> 40%) and marked sensitivity to CDDP and DOX; (c) the mp53 oncogene induces more resistance to VCR and insignificant resistance to the other drugs; and (d) activation of PKC by TPA increases the resistance to VCR and DOX in cells transformed by the v-H-ras, while it significantly increases the lethality with CDDP of the E1a-transformed cells. Staurosporine increases the cytoxicity of all the drugs, especially in the E1a-transformed keratinocytes. In the flow-cytometry analysis, the percentage of BUdR incorporation was related to sensitivity to anti-cancer drugs.

Animals↗
PubMed1995

Migraine and subsequent risk of stroke in the Physicians' Health Study.

OBJECTIVE: To evaluate, in a prospective design, whether migraine is an independent risk factor for subsequent stroke. DESIGN: Evaluated as part of the Physicians' Health Study, a randomized, double-blind, placebo-controlled trial of aspirin and beta-carotene in the primary prevention of cardiovascular disease and cancer begun in 1982. The aspirin component of the study was terminated in 1988, with average follow-up of 60.2 months. SETTING: Conducted by mail among male physicians throughout the United States. PARTICIPANTS: A total of 22,071 US male physicians aged 40 to 84 years in 1982 with no prior history of cancer or cardiovascular diseases who were enrolled in the Physicians' Health Study. INTERVENTIONS: Participants were randomized to receive 325 mg of aspirin or aspirin placebo every other day and to receive 50 mg of beta-carotene or placebo on alternate days. MAIN OUTCOME MEASURES: The primary outcomes of the Physicians' Health Study were cardiovascular disease and cancer. Because stroke was a main outcome, this provided the opportunity to evaluate the association between migraine headaches and stroke. RESULTS: Physicians reporting migraine (n = 1479) had significantly increased risks of subsequent total stroke and ischemic stroke compared with those not reporting migraine. After adjustment for age, aspirin and beta-carotene treatment assignment, and a number of cardiovascular risk factors, the relative risks were 1.84 (95% confidence interval, 1.06 to 3.20) for total stroke and 2.00 (95% confidence interval, 1.10 to 3.64) for ischemic stroke. There were too few hemorrhagic strokes in the study to evaluate this end point. No associations were seen between ordinary nonmigraine headache and subsequent stroke or between migraine and subsequent myocardial infarction or cardiovascular death. CONCLUSION: These data raise the possibility that vascular events associated with migraine may also have causative importance in stroke but require confirmation in other studies specifically designed to evaluate this question.

Adult↗
PubMed1995

The endogenous cannabinoid receptor ligand, anandamide, inhibits the motor behavior: role of nigrostriatal dopaminergic neurons.

The present study has been designed to test whether the recently described endogenous ligand for the cannabinoid receptor, arachidonylethanolamide, termed anandamide, can mimic the effects produced by exogenous cannabinoids on motor behavior and to test possible neurochemical substrates for this potential effect. To this end, adult male rats were submitted to an acute i.p. injection of anandamide, delta 9-tetrahydrocannabinol (THC) or vehicle. Animals were behaviorally tested ten minutes after injection of the drug and, then, sacrificed and their brains used for dopaminergic analyses. Ambulation was not significantly affected by the treatment with either THC or anandamide, but a very pronounced increase was observed in the time spent in inactivity in rats treated with either THC or anandamide. This was accompanied by a marked decrease in the frequency of spontaneous non-ambulatory activities, such as grooming and rearing, although only the administration of THC decreased shaking behavior. The anandamide-induced decrease in grooming was dose-dependent, but the decrease in rearing was higher with the dose of 3 mg/kg than with the dose of 10 mg/kg. The administration of anandamide also caused a dose-dependent decrease in the activity of tyrosine hydroxylase and in the ratio between the number of D1 and D2 receptors in the striatum. Moreover, the administration of 3 mg/kg of anandamide significantly decreased the contents of dopamine and L-3,4-dihydroxyphenylacetic acid in the striatum although lesser and higher doses were less effective. THC only tended to decrease these parameters. No changes were seen in dopaminergic activity in the limbic forebrain after either cannabimimetics. In summary, anandamide, as well as THC, decreases motor behavior. This effect was paralleled by reduction in the activity of nigrostriatal dopaminergic neurons. However, subtle differences in the behavioral and neurochemical effects between anandamide and THC could be observed.

Animals↗
PubMed1995

Human processing of colour information in the chromatic-frequency domain.

On the basis of MacAdam's data, we have computed a psychophysical function which characterizes the transference of the colour information processed by the human visual system in the chromatic frequency domain. This function, obtained using chromatic-discrimination criteria, shows a cut-off frequency between 0.01375 and 0.02 c/nm, depending upon the colour-tolerance units adopted.

Color Perception↗
PubMed1995

Changes in rat brain cannabinoid binding sites after acute or chronic exposure to their endogenous agonist, anandamide, or to delta 9-tetrahydrocannabinol.

A brain constituent, the N-amide derivative of arachidonic acid, termed anandamide, has been recently proposed as a possible endogenous ligand for the cannabinoid receptor. The present study has been designed to examine whether the acute or chronic exposure to anandamide affected the binding of cannabinoid receptors in specific brain areas as occurred with the exogenous cannabinoid agonist, delta 9-tetrahydrocannabinol (THC). To this end, we measured the maximum binding capacity (Bmax) and the affinity (Kd) of cannabinoid receptors, by using [3H]CP-55,940 binding assays, in membranes obtained from several brain areas of male rats acutely or chronically treated with anandamide or THC. Results were as follows. The acute administration of either anandamide or THC increased the Bmax of cannabinoid receptors in the cerebellum and, particularly, in the hippocampus. This effect was also observed after 5 days of a daily exposure to either anandamide or THC. However, whereas the increase in the Bmax after the acute treatment seems to be caused by changes in the receptor affinity (high Kd), the increase after the chronic exposure may be attributed to an increase in the density of receptors. On the contrary, the [3H]CP-55,940 binding to cannabinoid receptors in the striatum, the limbic forebrain, the mesencephalon, and the medial basal hypothalamus was not altered after the acute exposure to anandamide or THC. However, the chronic exposure to THC significantly decreased the Bmax of these receptors in the striatum and nonsignificantly in the mesencephalon. This effect was not elicited after the chronic exposure to anandamide and was not accompanied by changes in the Kd.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesics↗
PubMed1995

Lignan models as inhibitors of Phanerochaete chrysosporium lignin peroxidase.

The lignan 8,8'-bis-(methylenedioxy)cinnamic acid (BMDCA) is a powerful competitive inhibitor (K1 = 2.0 microM) of the lignin peroxidase (LiP) from Phanerochaete chrysosporium and of the extracellular peroxidase of Phlebia radiata (I0.5 = 10 microM). BMDCA derivatives with the same double bond system also inhibited these enzymes to some extent. If the double bonds were hydrogenated, the inhibitory effect was lost. HRP-VIII and HRP-XI were slightly inhibited by BMDCA (I0.5 > 50 microM) and two plant peroxidases described as efficient lignan synthesizers were unaffected. Liquid cultures of P chrysosporium did not discolour the dve Poly R478 when 250 microM of BMDCA was present.

Anthraquinones↗
PubMed1995

Nosocomial transmission of tuberculosis infection in pediatrics wards.

Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.

Child↗
PubMed1995

Low protein concentration in cirrhotic ascites is related to low ascitic concentrations of immunoglobulins G and A.

OBJECTIVE: To analyse the differences in ascitic and serum levels of immunoglobulins and albumin between two groups of cirrhotic patients (with ascitic total protein levels higher and lower than 10 g/l). DESIGN: A prospective study. PATIENTS AND METHODS: We studied 39 cirrhotic patients with sterile ascites. The patients were classified into two groups: group A (18 patients) comprised those with an ascitic total protein level less than 10 g/l and group B (21 patients) those with an ascitic total protein level higher than 10 g/l. Ascitic and serum levels of albumin and immunoglobins G, A and M were analysed. RESULTS: Ascitic immunoglobulin G and A levels in group B were higher than ascitic immunoglobulin G and A levels in group A. Ascitic levels of these immunoglobulins correlated linearly with ascitic total protein levels. The serum levels of immunoglobulins G and A in groups A and B were not significantly different. Ascitic and serum immunoglobulin M concentrations in the two groups were similar. Transfer of immunoglobulins G and A and albumin from plasma to ascites seemed to be similar in group B. Transfer of immunoglobulins G and A seemed to be impaired in group A. Differences in ascitic immunoglobulin levels between groups A and B were also observed in the presence of diuretic treatment. Differences in ascitic immunoglobulin levels were related to the Child-Pugh score. CONCLUSION: Patients with a low ascitic total protein level show low ascitic immunoglobulin G and A concentrations. The low ascitic immunoglobulin G and A levels could be related to an impairment in the transfer of these immunoglobulins from plasma in those patients who have poor liver function. Ascitic immunoglobulin M is not related to ascitic total protein, and its origin is not clear. The putative transfer of immunoglobulin M to the peritoneal cavity is not related to the mechanism of transfer of albumin or of immunoglobulins G and A from serum. The physiological significance of ascitic immunoglobulin M is unclear.

Adult↗
PubMed1994

[Effectiveness of anti-flu vaccine in the elderly].

OBJECTIVE: To evaluate the effectiveness of anti-flu vaccination on elderly people not in institutions, by measuring its effect on the reduction of deaths and hospital admissions due to Cardio-respiratory failure. DESIGN: A retrospective cohort. SETTING: La Chana Health Centre, Granada. PATIENTS AND OTHER PARTICIPANTS: 1,965 elderly people who were seen at the Health Centre over the previous three years. MEASUREMENTS AND MAIN RESULTS: 779 elderly people (39.6%) were vaccinated. 35 were admitted to hospital with Cardio-respiratory failure and 59 died. Of these two groups, 13 and 23 respectively had been given the anti-flu vaccination that year. After checking for variables which could lead to confusion, the vaccine was shown to be effective both in reducing admissions (advantage ratio 1,330) and deaths (advantage ratio 1,221). CONCLUSIONS: Given the effectiveness of anti-flu vaccinations, active efforts to encourage non-institutionalised elderly people to be vaccinated should be increased.

Aged↗
PubMed1994

Functional and ligand binding specificity of the rabbit neutrophil IL-8 receptor.

IL-8 mediates migration and activation of neutrophils. This study describes the functional and ligand binding specificity of the human intercrine peptides IL-8, neutrophil-activating peptide 2 (NAP-2), melanoma growth stimulatory activity (GRO), and platelet factor 4 (PF4) to rabbit neutrophils and mammalian cell lines transfected with rabbit IL-8 receptor cDNA (F3R). Rabbit neutrophil membranes bound 125I-labeled IL-8 and 125I-labeled NAP-2 but did not bind 125I-labeled GRO or 125I-labeled PF4. Rabbit neutrophils mobilized intracellular Ca2+ in response to IL-8 and NAP-2 but not to GRO or PF4. Monkey kidney cells (COS-7) and hamster lung fibroblasts (CCL-39) were transiently and stably transfected with the rabbit neutrophil IL-8 receptor F3R cDNA. COS-7 cells transfected with F3R cDNA bound 125I-labeled IL-8 but did not bind other IL-8-related peptides such as 125I-labeled NAP-2, 125I-labeled GRO, or 125I-labeled PF4. Furthermore, bound 125I-labeled IL-8 was only displaced by unlabeled IL-8 but not by unlabeled NAP-2, GRO alpha, or PF4. Consistent with this observation, stably transfected CCL 39 cells expressing F3R cDNA mobilized Ca2+ only in response to IL-8. We conclude that F3R cDNA encodes a functional IL-8 receptor isotype with strict ligand binding specificity for IL-8, that rabbit neutrophils do not bind human GRO alpha, and it is suggested that rabbit neutrophils contain in addition to the F3R protein another IL-8 receptor isotype with broad ligand specificity or a distinct NAP-2 receptor.

Animals↗