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Biomedical subjects

A Oliver

Publications and source records attributed to A Oliver.

At least 91 records · Page 5Linked to original sources
PubMed1995

Abnormal polymerization and normal binding of plasminogen and t-PA in three new dysfibrinogenaemias: Barcelona III and IV (gamma Arg 275-->His) and Villajoyosa (gamma Arg 275-->Cys).

Congenital dysfibrinogenaemia was found in three non-related patients. None of them had a haemorrhagic tendency, but one gave a thrombotic history. When their fibrinogens were treated with thrombin, they released fibrinopeptides A and B at normal rates, but the resultant fibrin monomers produced exhibited abnormal polymerization curves. This abnormality was more marked in fibrinogen Villajoyosa than in Barcelonas III and IV. Plasminogen and t-PA binding to fibrin monomers from the three dysfibrinogenaemias was similar to that of normal fibrin monomers. The gamma chain was purified from the three fibrinogens, treated with CNBr and the peptides produced were separated by reversed-phase HPLC. Chromatograms of digested fibrinogens showed an abnormal peak that was not present in the normal gamma chain. Amino acid sequence analysis of abnormal peptides and genomic DNA sequencing revealed that the gamma arginine 275 had been changed in the three fibrinogens; in two cases it was substituted by histidine, and in the third by cysteine. The altered properties observed in fibrin monomers produced from fibrinogen with the gamma Arg 275-->His or gamma Arg 275-->Cys substitution, suggests that this amino acid is important in maintaining the protein structure necessary for normal polymerization, but is not essential for the binding of t-PA or plasminogen to fibrin. It also suggests that the change Arg-->Cys produces more severe alterations in the functions of fibrinogen than the substitution Arg-->His.

Adult↗
PubMed1995

The effect of endogenous oestradiol levels on protein S concentration during a menstrual cycle and after GnRH analogues and gonadotropin therapy.

We studied two groups of females to investigate the effect of endogenous oestradiol levels on total and free protein S (tPS, fPS) plasma concentrations. One group (group I) consisted of 12 healthy volunteers who were studied throughout one menstrual cycle; the other group (group II) consisted of 16 young women who were treated with GnRH analogues and gonadotropins before undergoing in vitro fertilization. Neither tPS nor fPS varied significantly with respect to the physiological changes of oestradiol or to the very low and high levels of oestradiol, achieved after GnRH analogues suppression and gonadotropin stimulation. These results indicate that endogenous oestradiol does not affect PS concentration.

Adolescent↗
PubMed1994

Postrenal transplant erythrocytosis: further evidence implicating erythropoietin production by the native kidneys.

True erythrocytosis is a relatively common complication of successful renal transplantation. From a group of 17 patients with post-transplant erythrocytosis (PTE), four underwent selective venous catheterization of the native and transplanted kidneys because of arterial hypertension. In three who presented with active PTE at the time the procedure was performed the peripheral blood (PB) concentration of EPO was elevated, and the level of erythropoietin (EPO) in native kidney veins was significantly higher than the PB and allograft EPO levels. Additionally, only one of the three cases had high levels of plasma renin activity (PRA). The fourth patient showed normal levels of EPO and PRA in PB and in venous blood from the native and transplanted kidneys. However, the PTE had subsided 4 months before the performance of the catheterization after he redeveloped terminal renal failure; the loss of a functioning allograft might have blunted the overproduction of EPO by the native kidneys. In conclusion, in patients with PTE, inappropriate EPO production seems to originate from the diseased native kidneys, and there seems to be no correlation between the production of EPO and the PRA.

Adult↗
PubMed1994

Growth hormone response to growth hormone-releasing hormone stimulation in oligozoospermic patients.

OBJECTIVE: To evaluate the GH response to growth hormone-releasing hormone (GH-RH) stimulation in oligozoospermic men. SETTING: Outpatient Clinic of Andrology at the Fundación Puigvert and the Department of Clinical Chemistry, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. PATIENTS: Fifteen oligozoospermic patients and 15 normozoospermic fertile men matched for age and body mass index. INTERVENTION: Endocrine status was determined by assay of basal levels of gonadotropins (FSH, LH), T, E2, inhibin, and insulin-like growth factor I (IGF-I). Serum GH levels were measured before and after GH-RH administration. RESULTS: GH response to GH-RH was significantly greater in patients than in controls. There was a positive correlation between the GH response and IGF-I levels in oligozoospermic patients only. Regression analysis showed a significant negative association of GH peak with inhibin after controlling for IGF-I in oligozoospermic patients. CONCLUSION: The results indicate that there is an altered responsiveness of pituitary to GH-RH administration in oligozoospermic patients; this did not appear to be due to the influence of gonadal steroid levels but rather to inhibin or some related peptide.

Adult↗
PubMed1993

[Pregnancy and thrombophilia in women with congenital deficit of antithrombin III, protein C, protein S or plasminogen: analysis of 39 cases].

BACKGROUND: Pregnancy, delivery and puerperium are situations which increment the risk of thromboembolic complications in women who are carriers of congenital heterozygotic deficits of type I antithrombin III (ATIII), protein C (PC) or protein S (PS). The aim of this study was to analyze the experience of the authors and propose therapeutic conduct in each case. Furthermore, the spontaneous losses of pregnancy related with these deficits were studied. METHODS: Thirty-nine women, seventeen with ATIII deficit, fifteen with PC deficit and four with a deficit of PS and three with a plasminogen (Pg) deficit totalling 79 pregnancies and 51 thrombotic episodes sixteen of which were related with the pregnancy, delivery or puerperium were studied. The antigenic and functional activity of ATIII, PC, PS and Pg were determined. RESULTS: The incidence of thrombosis for the ATIII deficit during pregnancy was 39%, which was greater, of statistical significance (p = 0.046), than the 15% observed during puerperium. In women with a deficit of PC, the incidence of thrombosis was 4.5% during pregnancy and 14% during puerperium with no significant difference between the two situations. The incidence of thrombosis during pregnancy and postpartum in the deficit of ATIII was significantly higher (p < 0.025) than that observed for the deficit of PC. For women with a deficit of PS and Pg the incidence of thrombosis was nul in pregnancy and puerperium. CONCLUSIONS: Pregnancy and puerperium are situations which trigger thrombotic phenomena and increase the risk of the same in women with a deficit of antithrombin III and protein C and, to a lesser degree, the deficit of protein S or plasminogen. A strict control of these situations and individualized treatment is required according to the type of deficit, presence of previous thromboembolic history and anticoagulant history at the time of pregnancy. No increase in the risk of loss of pregnancy in any of the deficits studied was observed.

Adult↗
PubMed1993

Lack of effect of influenza vaccine on anticoagulation by acenocoumarol.

OBJECTIVE: To analyze the effects of influenza vaccine on patients receiving chronic anticoagulant therapy with acenocoumarol. DESIGN: A prospective trial. SETTING: Hospital de la Santa Creu i Sant Pau, Barcelona. PATIENTS: Forty-three patients who received acenocoumarol, had stable levels of International Normalized Ratio (INR), and did not need dosage modification for four months before entering the study. INTERVENTION: A study of anticoagulation levels measured by INR at 7, 15, and 30 days from administration of the trivalent vaccine from the 91-92 campaign was conducted. MAIN OUTCOME MEASURES: Comparison was made between basal values (day 0) and anticoagulation levels at 7, 15, and 30 days from vaccine administration by means of a repeated-measures ANOVA. RESULTS: Nine patients (21 percent) had INR levels out of the therapeutic range during the study period. INR increased in three of these patients and decreased in six. There were no significant intraindividual changes in INR values during the time period analyzed (p = 0.125). No hemorrhagic or thrombotic manifestations occurred and no significant changes in renal or hepatic biochemistry were observed. CONCLUSIONS: Influenza vaccine does not modify acenocoumarol activity in patients receiving long-term anticoagulant therapy.

Acenocoumarol↗
PubMed1993

A controlled trial of home-based acute psychiatric services. I: Clinical and social outcome.

While research has shown community-based psychiatric care to be as good as, or better than, hospital-based care, generalisation to clinical practice has been difficult. This prospective, randomised controlled study examined a community-based approach feasible within NHS conditions. Ninety-four patients were randomly allocated to experimental and 78 to control treatments and followed for one year. The groups were well matched apart from an excess of psychotic control patients. No differences in clinical or social functioning outcome were found. Both groups improved substantially on clinical measures in the first six weeks, with some slow consolidation thereafter. There were three suicides in the control group and one in the experimental group. Access to care was better in the experimental group (93% attended assessment) than in the control group (75% attended assessment).

Adolescent↗
PubMed1992

[Influence of chronic renal failure and of its treatment on serum erythropoietin].

BACKGROUND: In order to know the influence of dialysis treatment in erythropoietin production, serum erythropoietin (Ep) has been studied in patients with anemia due to chronic renal failure (CRF). METHODS: Thirty six of them in hemodialysis (HD), 10 in continuous ambulatory peritoneal dialysis (CAPD) and 18 in predialysis stage (PD) and their results were compared to two control groups, including 72 healthy controls (HC) and the second one 89 iron deficiency anemia patients (ID). RESULTS: Patients had lower Hb and Ep levels than the other groups. Although Ep was higher in CAPD and PD. Ep levels were similar to HC values, and lower than ID levels. It could be demonstrated any correlation between Hb and Ep in CRF patients, however a negative exponential correlation was demonstrated in ID patients between Hb and Ep (r = -0.83; p less than 0.00001). In summary, Ep is higher in CAPD and in PD than in HD, but the levels are lower than they should be expected. CONCLUSIONS: These data confirm an Ep production failure in most of IRC patients and it seems likely that Ep treatment could be effective to treat the anemia of CRF.

Anemia↗
PubMed1992

[Pyknodysostosis: extreme cause of sleep apnea].

We describe a twentieth month old infant who had a pycnodysostosis syndrome. This malformation shows a loss of the normal mandible angle with generalized bone hyperdensification. The first produced and airway obstruction, with special relevance during sleeping hours. A polysomnography revealed an obstructive sleep apnea syndrome. The respiratory picture deteriorated with worsening of the airway obstruction, hypoxemia and finally pulmonary hypertension and cor pulmonale. A tracheostomy was performed, with resolution of the sleep apnea and pulmonary hypertension. The etiology, pathophysiologic consequences and surgical treatment of obstructive sleep apnea syndrome is reviewed.

Abnormalities, Multiple↗
PubMed1991

Bicuculline-induced epileptogenesis in the human neocortex maintained in vitro.

Intracellular and extracellular recordings were made from human neocortical slices of the temporal lobe maintained in vitro. The slices were treated with bicuculline methiodide to reduce synaptic inhibition mediated by tha gamma-aminobutyric acid A (GABAA) receptor. Spontaneously occurring epileptiform activity was never observed in over 60 slices examined. All epileptiform discharges were elicited by single-shock stimuli delivered in the underlying white matter or within the cortical layers. Intracellularly, the stimulus-induced epileptiform discharge resembled the paroxysmal depolarization shift (PDS). This potential was observed in neurons located between 200 and 2200 microns from the pia. It was characterized by a 100-1800 ms long depolarization which triggered burst firing of action potentials, and was at times followed by an afterdischarge. Simultaneous intracellular and extracellular recordings showed that each PDS was reflected by the synchronous discharge of a neuronal aggregate. The voltage behaviour of the PDS and its preceding EPSP was analyzed in cells that were injected with the lidocaine derivative QX-314. The amplitudes of the PDS depolarizing envelope measured at its peak and during its falling phase both behaved as a monotonic function of the membrane potential by increasing in amplitude during hyperpolarization. In addition, the PDS peak amplitude showed a much greater rate of increase than the early EPSP peak amplitude, thus suggesting that the synaptic conductance underlying the PDS was much greater. Perfusion of the neocortical slices with the N-Methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-phosphonovaleric acid (APV) reduced both the duration and the amplitude of the paroxysmal field discharge in a dose related fashion. The effects of APV were reflected intracellularly by an attenuation of the PDS's late phase and a blockade of the afterdischarge. Similar findings were also obtained by using the NMDA receptor antagonist 3-((+-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid. These data indicate that reduction or blockade of the GABAA receptor is sufficient to elicit epileptiform discharges in the human neocortex maintained in vitro. Mechanisms dependent upon the NMDA receptor contribute to this type of epileptiform response mainly by prolonging the stimulus-induced depolarizing potential and the associated burst of firing.

2-Amino-5-phosphonovalerate↗
PubMed1991

[Markers of hypercoagulability during pregnancy: thrombin-antithrombin-III complexes and D dimer].

Pregnancy can be regarded as a secondary hyper-coagulability state. The development of thrombin-anti-thrombin complexes (TATC), D dimer and anti-thrombin III (AT III) was analysed in the present work on 33 pregnant women. A significant increase of the TATC records was found between the first and third trimesters and between the second and third trimesters (p = 0.005 and p = 0.02, respectively). The AT III values were within the normal range. The values of the D dimer increased progressively during pregnancy, but only the figures achieved in the third trimester were statistically significant with respect to the control group (p = 0.14). The increase of TATC and D dimer during pregnancy are considered as hypercoagulability.

Adult↗
PubMed1990

[Importance of antiphosphatidylserine antibodies in patients with lupus anticoagulant. Analysis of 30 cases].

Anti-phosphatidylserine (APS) and anticardiolipin (ACL) antibodies were measured in 30 patients with lupus anticoagulant. In 17 cases there were clinical features of thrombosis (56.7%). The number of patients with IgG APS and ACL levels higher than seven standard deviations from the normal mean was significantly higher in the group with thrombosis (p less than 0.017 and p less than 0.02, respectively). The IgG APS level was higher in the group without systemic lupus erythematosus (p less than 0.029). There was a positive correlation between IgG APS and the activated thromboplastin time (r = 0.654, p less than 0.001). The correlation between IgG APS and IgG ACL was rho = 0.61. Two of the 5 patients with increased IgG APS and normal IgG ACL had thrombosis. We think that, in this group of patients, IgG APS titer may be, like IgG ACL, a biological marker of thrombosis risk.

Adult↗
PubMed1990

Effects of different dose levels and vaccination schedules on immune response to a recombinant DNA hepatitis B vaccine in haemodialysis patients.

Hepatitis B is a frequent complication in haemodialysis patients because of their repeated exposure to blood products, and their impaired cellular and humoral response; trials with plasma-derived hepatitis B vaccine (PDV) show lower immune responses than those in healthy adults. Using a yeast-derived hepatitis B vaccine (YDV), the immunogenicity of two different dose levels (20 and 40 micrograms) and three vaccination schedules were compared in over 270 seronegative dialysis patients. Vaccination with 40 micrograms gave slightly better results than with the 20 micrograms dose. Seroconversion rates were higher with four dose, 40 micrograms vaccination schedules than a three dose schedule, and ranged from 80 to 86%. As the 40 micrograms, 0, 1, 2, 6 month schedule leads to a more rapid rise in antibody levels than the 40 micrograms, 0, 1, 2, 12 month schedule, it appears to be the most appropriate schedule in this patient group.

Adult↗
PubMed1990

[Detection of thrombin-antithrombin complexes in hypercoagulability conditions. Analysis of 182 cases].

The detection of TATC may inform about the presence of thrombin generation and, and hence of a pre-thrombotic status. An ELISA test (Enzygnst TAT) has been developed here in order to evaluate the predictive role played by TATC, and it was applied on 182 patients who distributed in 14 with cirrhosis of the liver, 11 with sepsis, 17 with chronic arterial insufficiency, 55 with neoplasms, 9 with thrombosis, 15 in postoperative period, 15 with pneumonia, 16 with disseminated intravascular coagulation (DIC), 14 with multiple injuries and 16 with pancreatitis. TATC levels were significantly increased in all groups with regard to the control group. Patients with thrombosis, sepsis, multiple injuries, DIC and in the postoperative period showed especially high TATC figures. No correlation between TATC and fibrinogen, platelet count, activated partial thromboplastin time or prothrombin complex assay was found in the post-operative patient-group. It was concluded that TATC are a good indicator of hypercoagulability.

Adult↗
PubMed1989

Immunogenicity of a yeast-derived hepatitis B vaccine in hemodialysis patients.

In a multicenter study of hemodialysis patients in Spain, the immunogenicity of a yeast-derived recombinant deoxyribonucleic acid hepatitis B vaccine was evaluated. Two different vaccination schedules were examined: zero, one, two, six months and zero, one, two, 12 months. Two different dose levels (20 micrograms and 40 micrograms) were also compared. No serious adverse effects were reported by any of the vaccinees; the most frequently reported reaction was soreness at the injection site. This study also indicated that higher concentrations of antibodies are attained when more frequent doses of vaccine are administered. The yeast-derived vaccine produced an immune response similar to that of the plasma-derived vaccines.

Clinical Trials as Topic↗
PubMed1989

Maintaining mosquito cell lines at high temperatures: effects on the replication of flaviviruses.

The upper thermal limit for maintenance of eleven mosquito cell lines was studied. Although most cell lines could be grown at 32 degrees C to 34 degrees C, Anopheles stephensi cell line could be maintained at 37 degrees C. At higher temperatures initial growth rate was higher, but yield of cells after about a week of incubation was lower than at the standard temperature (28 degrees C). Replication of several flaviviruses in Aedes albopictus cell cultures adapted to 34.5 degrees C was faster, and viral titers were higher than at 28 degrees C.

Animals↗