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Biomedical subjects

R Rubio

Publications and source records attributed to R Rubio.

At least 109 records · Page 6Linked to original sources
PubMed1992

Widespread dermatophytosis due to Microsporum (Trichophyton) gallinae in a patient with AIDS--a case report from Spain.

We report the case of a 25-year-old, HIV-positive patient (group IV, A, C2 clinical stage) with a widespread dermatophyte infection. He was a male gypsy with a known history of intravenous drug abuse. After an episode of cerebral toxoplasmosis for which he was treated with systemic steroids (because of cerebral oedema) he developed, over 16 days, a remarkably extensive ringworm of the trunk due to an unusual zoophilic dermatophyte, Microsporum (Trichophyton) gallinae. Human infection with this dermatophyte species is unusual: there are as few as seven proven reported cases, all of whom had localized lesions. This is the first widespread and severe case reported in man and also the first reported from Spain.

AIDS-Related Opportunistic Infections↗
PubMed1992

Isolated congenital heart defects in first degree relatives of 185 affected children. Prospective study in Mexico City.

Parents (n = 355) and siblings (n = 313) of 185 index cases (IC) with congenital heart disease (CHD) were cardiologically evaluated. In the consecutive sample (2 years) Mendelian and chromosome syndromes were excluded. Four patients and nine siblings had CHD. The frequency of affection in siblings was 2.6% (8 in 313 siblings). All affected relatives are under medical care at the Centro Médico Nacional Siglo XXI, IMSS. In 10 of the 12 affected relatives found, the type of CHD was discordant from that of the IC. Discordance was found also in 9 of 36 IC with two or more CHD. An interpretation is given: if the mutated gene(s) has its effect in early embryological stages, affected relatives may have any type of CHD, but if the alteration occurs later, concordance is expected to be found. This model contributes also in explaining the remarkable genetic heterogeneity that exists in CHD.

Adolescent↗
PubMed1992

Papilloma virus infection. Precancer and epidermoid cancer.

We present a review of the relationship between Human Papillomavirus (HPV), Precancer and Epidermoid Cancer of the uterine cervix, Co-factors that contribute in cervical carcinogenesis and the mechanism through which Papillomaviruses transform normal cells into neoplastic cells by inducing an overproduction of the encoded proteins. We also offer final remarks and conclusions on this pathology that increases its incidence every year.

Carcinoma, Squamous Cell↗
PubMed1992

[A molar pregnancy coexistent with a viable fetus in a twin pregnancy].

A case of molar gestation associated with an only fetus, both product of an twin gestation is presenting. We analyzed the clinical picture, the diagnostic method, the after birth resolution and evolution of this gestation. The result of a live newborn of 1,300 g and verify coexisting of complete hydatidiform mole.

Adolescent↗
PubMed1991

Syncope: etiology, prognosis, and relationship to age.

Syncope is a common and particularly troublesome problem in the elderly population. In a series of 146 patients admitted for syncope to an acute care hospital in Chile during a 4-year period, 2/3 (68%) were aged 65 years and older. A specific etiology could be established in 62%, and 3/4 of these were cardiovascular in origin. Diagnosis was established entirely on history, physical examination, resting ECG, and 24-hour cardiac monitoring in most cases but in some, more sophisticated measures (i.e., echocardiography, electrophysiologic studies, blood tests, EEG) were needed, and mostly to confirm clinically suspected problems. In-hospital mortality was 2.1% and mortality at the end of the approximately 2-year follow-up period was 18.1%. Mortality was higher for persons over age 65 than for younger persons (23.9% vs 2.3%), and for persons with cardiovascular syncope than for persons with other kinds of syncope (28.3% vs 8.9%). This study confirms the particular lethality of syncope in the elderly population and outlines a relatively simple strategy with which most syncope patients can be diagnosed without resorting to expensive procedures.

Adult↗
PubMed1991

Regulation of glycolytic flux by coronary flow in guinea pig heart. Role of vascular endothelial cell glycocalyx.

Hemodynamic forces continuously act on endothelial cell lining of blood vessels. Blood flow, perfusing pressure, and shear stress are known to induce the release of bioactive substances from the endothelium. Furthermore, coronary flow (CF) is a well-known stimulant of myocardial contraction. Our concern was whether other Ca(2+)-dependent responses like glycolytic flux (Gf) were also CF dependent. For this purpose, isolated guinea pig hearts were perfused with a medium containing 5 mM 3-[3H]glucose, and the 3H2O released during perfusion was measured as an index of Gf. Changes in CF within the 3- to 25-ml/min range resulted in linear increase of Gf. This stimulatory effect of CF was also observed in K(+)-arrested hearts. In addition, increasing shear stress on addition of dextran to the perfusing solution (5% and 10% wt/vol), while keeping CF constant, also stimulated Gf. We hypothesized that endothelial cell membrane glycocalyx may act as sensor to this stimuli. Thus one would expect that substances acting on these structures (enzymes heparinase, hyaluronidase, or chondroitinase or the lectin concanavalin A) when added to the perfusate might inhibit the CF-induced Gf. The results showed that concanavalin A and heparinase inhibited the Gf-CF-induced response, whereas chondroitinase and hyaluronidase had no effect. These findings suggest that there may be a selective effect of these agents affecting the Gf response to CF. Our data suggest that CF stimulates Gf through shearing forces acting on specific endothelial glycocalyx component(s). Therefore, deformation of these components could result in the transduction of physical signals into release of chemical messengers that act on the biochemical machinery of underlining parenchymal cells.

Adenosine↗
PubMed1991

[An epidemiological and immunological study of human immunodeficiency virus infection in the southern area of Madrid].

The clinical characteristics and immunological parameters are characterized in different groups of infection by human immunodeficiency virus (HIV) in patients infected by HIV, and the prognostic markers of survival in patients diagnosed of acquired immunodeficiency syndrome (AIDS). This study was carried out in 312 patients from June 1984 to March 1989. The most common risk group was intravenous drug addicts (IVDA) 80.9%. We observed that during the last years there was an increase in the number of cases of heterosexual transmission. Through follow up, 17.6% of patients developed acquired immunodeficiency (AIDS). The incidence rate for AIDS was higher amongst homosexuals than IVDA (35.4/14.6). Esophageal candidiasis and extrapulmonary tuberculosis were the AIDS indicators most frequently encountered. Once the study period was over, with a follow up of 19.3 +/- 3.4 months, the probability of survival after 12 months was 70 +/- 0.07% and after 24 months was 42% +/- 0.09%. The risk group (homosexuals), the appearance of a neoplasia as the first diagnosis of AIDS, and the immunological parameters (CD3 less than 500, CD4 less than 400, CD4/CD8 ratio less than 0.5 and total lymphocyte count of less than 1700 were the markers with worst prognosis which correlated with survival rates (p less than 0.01). We confirmed that when comparing immunologic parameters amongst HIV infection groups, IgA levels were higher (p less than 0.05); the total number of lymphocytes, the number of helper lymphocytes and the CD4/CD8 ratio were lower (p less than 0.01) in IV and AIDS group with respect to group II and III, in patients with AIDS with respect to group IV-non-AIDS and in those who died with relation to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Hodgkin's disease in patients with antibodies to human immunodeficiency virus. A study of 22 patients.

The experience of 22 Hodgkin's disease (HD) patients with human immunodeficiency virus type I (HIV) antibodies, collected from a cooperative study of six hospitals during 1984-1989 is presented. Young men (average age, 27.6 years) with a high incidence of intravenous drug abuse (86%) were found. The status of the HIV infection at diagnosis of HD was: four patients, acquired immune deficiency syndrome (AIDS); eight patients, persistent generalized lymphadenopathy (PGL); and ten patients, asymptomatic. The natural history of HD was unusual, with a high incidence of B symptoms (81%), advanced Stages III to IV (90%), bone marrow invasion (50%), cytopenias before treatment (45%), opportunistic infections (68%), and aggressive histologies. A decreased response to chemotherapy with poor marrow tolerance and a significant decrease in survival, 18 months, was observed. The AIDS and cytopenias pretreatment were associated with a shorter statistically significant survival, which defines the importance of immunodeficiency in HD prognosis. Complete remission after treatment was a factor that contributed to a longer statistically significant survival. The PGL or asymptomatic patients survived longer but also had a poor course, and five of them had AIDS criteria during evolution. A high incidence of HD in relation to non-Hodgkin's lymphoma (NHL) in patients with HIV infection in the six cooperating hospitals was found. Criteria for considering HD as an AIDS-associated lymphoproliferative disease in our environment are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Nitriles and isonitriles as interferents in cyanide determination in polluted waters.

The interference of nitriles and isonitriles in cyanide determination was studied using the pyridine-barbituric acid direct spectrophotometric method or the same method after distillation of the sample, a microdiffusion-potentiometric (ion-selective electrode) also being used. Phenylacetonitrile, benzonitrile, acrylonitrile, iminodiacetonitrile and acetonitrile were tested as nitriles. Benzyl isocyanide butyl isocyanide and 1-[(isocyanomethyl)sulphonyl]-4-methylbenzene were assayed as isonitriles. It can be concluded that both nitriles and isonitriles should be considered as interferents in all the methods of cyanide determination studied. The level of interference generally increases with the ratio of interfering compound to cyanide and is greatest for low cyanide concentrations.

Cyanides↗
PubMed1990

Time-dependent effects of theophylline on myocardial reactive hyperaemias in the anaesthetized dog.

1. The effects of a loading dose of theophylline (5 mg kg-1 i.v.) on the hyperaemias resulting from short-term (15 and 30 s) interruptions in coronary blood flow and intracoronary adenosine were studied at given intervals over a 2 h period in the anaesthetized dog. 2. These hyperaemic responses were affected differently by theophylline and each effect was time-dependent. The reactive hyperaemic response progressively decreased after drug delivery, reaching 46% of control at 2 h. In contrast, after a maximal attenuation to 23% of control 5 min after theophylline, the hyperaemia resulting from intracoronary adenosine progressively increased over the same period, reaching 64% of control 2 h after the loading dose. 3. Two-compartment model results based on plasma theophylline measurements and the time course of theophylline accumulation in pericardial infusates, suggested that complete drug distribution throughout the heart may require at least 20 min following a single intravenous dose. 4. If it is assumed that theophylline blocks coronary vascular adenosine receptors, these pharmacokinetics are consistent with the time-dependent pattern of response attenuation we observed for the adenosine-induced hyperaemias, but they cannot entirely explain the pattern of response attenuation observed for the occlusion-induced hyperaemias. The continued increase in attenuation of this response after complete drug distribution suggests an additional pharmacodynamic action of theophylline. 5. We conclude that a single therapeutic dose of theophylline results in distinct time-dependent pharmacological effects with respect to the ability of the coronary vasculature to dilate in response to temporary interruptions in oxygen supply and in response to exogenously administered adenosine. These effects deserve consideration in both experimental studies in which adenosine antagonists are used to assess adenosine action in vivo, and in clinical practice where theophylline pharmacotherapy for pulmonary disorders is commonplace.

Adenosine↗
PubMed1990

Interstitial adenosine in guinea pig hearts: an index obtained by epicardial disks.

Epicardial porous disks were used to estimate left ventricular interstitial fluid adenosine in the isolated guinea pig heart perfused at constant flow. To validate this technique, adenosine was infused with 0.5 microM dipyridamole and 5 microM erythro-4-(2-hydroxy-3-nonyl)adenine hydrochloride (EHNA) to inhibit adenosine uptake and deamination, respectively. Under these conditions, with 6 or 12 microM adenosine in the arterial infusate, the venous and steady-state left ventricular disk adenosine values equaled those of the perfusion fluid, reflecting the expected equilibration between vascular and left ventricular interstitial fluid (disk) compartments. The concentration of endogenous adenosine in the interstitial fluid as estimated by the epicardial disks under control conditions was 0.28 +/- 0.03 microM with a concomitant coronary sinus concentration of 0.004 +/- 0.001 microM. We conclude that a marked adenosine gradient exists between the interstitial fluid and the vascular space and that disk adenosine measurements provide a useful index of left ventricular interstitial fluid adenosine.

Adenosine↗
PubMed1990

[Syncope: recurrence and prognosis during 2 years].

We followed up 143 patients that had been admitted to intensive care units of a general hospital with syncope. 127 patients (89%) remained in follow up for a mean of 24 months (range 3 to 54 months). There were 70 men and 57 women and the mean age was 71.5 years. Recurrences were observed in 21 patients (17%) and were similar for patients whose syncope had a cardiovascular origin (10%), non cardiovascular origin (25%) or an undetermined cause (18%). Mortality from cardiac or vascular causes was 20% in the cardiovascular origin group, and 5 and 4.2% in the other groups, respectively (p less than 0.005). Recurrence did not influence mortality. A history of hypertension, cerebrovascular accidents and ventricular arrhythmias was associated to higher mortality risk (p less than 0.05).

Adult↗
PubMed1989

[Histiocytosis of Langerhans cells: a study of 40 cases].

Forty cases of histiocytosis of Langerhans' cells (26 children and 14 adults) were evaluated; 20 were localized forms (with single or multiple bone involvement); another 20 were generalized forms, with organic dysfunction (lung, liver, hemopoietic system) in 7 children. This feature has a poor prognostic significance, as shown by the fact that 3 of these 7 patients died. In 3 patients single skin involvement was found, with spontaneous recovery one month after the diagnosis in one; in one case the single involvement was lymphadenopathic, associated to Hodgkin's lymphoma, and in another it was hypothalamic. These cases of single involvement have been followed up between 1 and 4 years. In 4 of 7 patients with generalized disease a reduction of OKT8 with an increased OKT4: OKT8 ratio was found, as reported in other cases from the literature. This finding gives support to an immunological rather than neoplastic basis for the disease. In all 40 cases the diagnosis was morphological, with positive staining for S-100 protein in 38.

Adolescent↗
PubMed1989

The effect of local infusion of adenosine and adenosine analogues on local cerebral blood flow.

The purpose of this study was to determine the effects of local infusion of adenosine (ADO) and non-metabolized ADO analogues on local cerebral blood flow (CBF) and interstitial fluid (ISF) ADO levels. The brain dialysis technique was used to (a) deliver drugs locally to brain tissue, (b) estimate cerebral ISF ADO levels, and (c) measure local CBF (hydrogen clearance). Dialysis probes were implanted bilaterally in the caudate nuclei of ketamine-anesthetized rats. The probe on one side was perfused with artificial CSF while the contralateral probe was perfused with artificial CSF containing ADO (n = 5), or the ADO agonists 2-chloroadenosine (2-CADO; n = 4) or 5'-N-ethylcarboxamide adenosine (NECA; n = 4). When ADO was included in the artificial CSF at 10(-5), 10(-4), or 10(-3) M, a 30% increase in local CBF was detected only with 10(-3) M ADO. During perfusion with ADO, dialysate inosine and hypoxanthine levels increased, indicating that the cells adjacent to the probe metabolized the exogenous ADO. With 2-CADO included in the artificial CSF at 10(-6), 10(-5), or 10(-4) M, local CBF increased 18, 131, and 201%, respectively. Perfusion with artificial CSF containing 10(-7), 10(-6), or 10(-5) M NECA resulted in a 35, 112, and 187% increase in local CBF, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Chloroadenosine↗
PubMed1989

Inositol phospholipid metabolism during and following synaptic activation: role of adenosine.

The metabolic pathway of inositol phospholipids represents a series of synthetic and hydrolytic reactions with inositol as a by-product. Hence, the rate of [3H]inositol release from prelabeled phospholipids can be used as a reflection of activity of this pathway. In the frog sympathetic ganglion prelabeled with [3H]inositol, we studied the effect of synaptic activity (orthodromic stimulation) on release of 3H-label into the medium. This release was interpreted as [3H]inositol release. The value was low at rest and increased significantly by 32% during orthodromic stimulation (20 Hz for 5 min). However, on cessation of the stimulation, [3H]inositol release increased rapidly by 148% and remained elevated for at least 45 min. This increase in [3H]inositol release during and after the stimulation period was reduced by suffusion of the ganglia with adenosine. We hypothesized that synaptic activation releases a long-lasting stimulatory agonist and a short-lasting inhibitory (adenosine) agonist or agonists affecting [3H]inositol release. To demonstrate the presence of a stimulatory agonist, two sympathetic ganglia were used. One was prelabeled with [3H]inositol, and the other was not. The two ganglia were placed together in a 5-microliter droplet of Ringer's solution containing atropine. Orthodromic stimuli applied to the nonlabeled ganglion elicited release of [3H]inositol from the nonstimulated ganglion. To test whether the adenosine formed during orthodromic stimulation inhibits [3H]inositol release, we destroyed endogenous adenosine by suffusion of the ganglia with adenosine deaminase during the stimulation period. We found that adenosine deaminase induced large increases in [3H]inositol release during the stimulation period, in contrast to an increase seen only during the poststimulation period when adenosine deaminase was omitted. Because [3H]inositol release is assumed to parallel changes in content of inositol phosphates, we anticipated no changes of the levels of these compounds during orthodromic stimulation. However, measurements showed that levels of inositol phosphates and inositol phospholipids were all elevated except for phosphatidylinositol 4-phosphate. On termination of the stimulus, they remained elevated, with a further increase in levels of inositol trisphosphate and phosphatidylinositol 4-phosphate. We conclude that endogenous adenosine inhibits [3H]inositol release, possibly by modulating several of the steps of the inositol phospholipid pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1989

Adenosine formation and release by embryonic chick neurons and glia in cell culture.

Adenosine formation and release were studied in 48-h-old cultured ciliary ganglia and confluent peripheral and CNS glial cultures from embryonic chicks. Metabolic poisoning induced by 30 mM 2-deoxyglucose and 2 micrograms/ml oligomycin reduced ATP concentration by 90%. An increase in adenosine accounted for 15-40% of the fall in ATP. Dilazep (3 X 10(-6) M), a nucleoside transport inhibitor, decreased both incorporation of adenosine (an index of nucleoside transport) and release of adenosine by 80-90%. Dilazep trapped the newly formed adenosine intracellularly. A concentration of alpha, beta-methylene ADP that inhibited ecto-5'-nucleotidase by 80-90% did not alter the concentration of adenosine or AMP in neurons, glia, or medium. The results demonstrate that adenosine is formed intracellularly and exported out of the cell via the nucleoside transporter. The participation of ecto-5'-nucleotidase was excluded.

5'-Nucleotidase↗