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Biomedical subjects

F Velasco

Publications and source records attributed to F Velasco.

At least 73 records · Page 4Linked to original sources
PubMed1993

Serum TNF levels in neonatal sepsis and septic shock.

Tumor necrosis factor (TNF-alpha) has been implicated as a principal mediator in the pathogenesis of septic shock. TNF-alpha was measured by immunoradiometric assay in serum samples from 23 full-term infants with sepsis (15 with severe infection and 8 with septic shock) and in 20 healthy full-term newborns. Serum TNF-alpha levels were significantly higher in the group with sepsis, at the time of admission to the neonatal intensive care unit, than in the healthy neonates. The highest TNF levels were found in those newborns with septic shock, particularly in those who died. Although the method is far too slow for any clinical routine work, our results suggest that the presence of elevated serum TNF-alpha levels could be considered a sensitive and specific test for predicting septic shock and its clinical outcome.

Female↗
PubMed1993

Endotoxin-induced pulmonary dysfunction is prevented by C1-esterase inhibitor.

In septic shock, hypotension, disseminated intravascular coagulation, and neutrophil activation are related to the activation of the blood coagulation contact system. This study evaluates in dogs the effect of the C1-esterase inhibitor (C1-INH), a main inhibitor of the blood coagulation contact system, on the cardiovascular and respiratory dysfunction associated with endotoxic shock. Two groups were included: controls, which received Escherichia coli endotoxin, and a C1-INH group in which C1-INH was infused before E. coli endotoxin administration. In both groups, endotoxin produced hypodynamic shock; however, the decrease in the systolic index and the ventricular systolic work indexes were greater in controls than the C1-INH group. In controls, the arterial O2 partial pressure decreased by 30% and the alveolo-arterial O2 difference increased by 625%, these parameters remained unchanged in the C1-INH group. Hypoxemia was associated with increased intrapulmonary shunt, decreased blood coagulation contact factors, and decreased C3c. In contrast, C1-INH administration prevented endotoxin-induced hypoxemia, the increase in intrapulmonary shunt, and the decrease in blood coagulation contact factors. This study shows that, in dogs with endotoxic shock, pulmonary dysfunction is associated with an activation of the blood coagulation contact phase system. An inhibition of this system by C1-INH prevented the hypoxemia induced by endotoxic shock.

Animals↗
PubMed1993

Fibrinolytic activity during hemodialysis: a biocompatibility-related phenomenon.

According to recent reports, fibrinolytic activity may be enhanced during hemodialysis. The aim of this work was to study the fibrinolytic activity in uremic patients, and to evaluate the effect of membrane biocompatibility on the fibrinolytic system during hemodialysis. Tissue plasminogen activator (t-PA), t-PA antigen, plasminogen activator-inhibitor (PAI), plasminogen (PL) and alpha-2-antiplasmin (AP) were measured in 10 uremic patients on maintenance hemodialysis treated sequentially with Cuprophane and polyacrylonitrile (AN69) membranes. Blood samples were obtained before and at 15, 60 and 120 minutes after the initiation of dialysis. Blood was also collected from 20 healthy individuals who served as controls. During cuprophane dialysis, t-PA increased significantly at 60 minutes (14.8 vs. 8.4 IU/ml, P < 0.05) and at 120 minutes (13.8 P < 0.01). This was accompanied by an increase in t-PA antigen, which was significant at 15 (5.1 vs. 13.1 ng/ml), 60 (15.2) and 120 (9.6) minutes (P < 0.05) of dialysis. However, during AN69 dialysis t-PA and t-PA antigen plasma levels remained stable. No significant changes were observed in PL, AP or PAI during hemodialysis with either membrane. In conclusion, hemodialysis enhances fibrinolytic activity, which is likely the result of t-PA Ag release. Therefore, this phenomenon seems to be closely related to dialysis membrane biocompatibility.

Adult↗
PubMed1992

Diminished anticoagulant and fibrinolytic activity following liver transplantation.

This study analyzed the coagulation changes in twenty patients after orthotopic liver transplantation. The procoagulant, anticoagulant, and fibrinolytic systems were studied during the first two postoperative weeks. Within the first postoperative day all extrinsic and intrinsic pathway factors became normal except factors IX, VII, and X, which recovered within the next 24 hr. Of interest are the changes in factor VIII, which reached a high concentration with an increase in its antigenic fraction during the study. However, coagulation inhibitors showed a different pattern. In fact, antithrombin III (AT-III) and protein C (PC) needed from 7 to 14 days to reach normal values. Total protein S (TPS) and free protein S (FPS) did not recover until day 7, whereas heparin cofactor II (HC-II) remained at subnormal levels throughout the study. Thrombin-antithrombin III complex (TAT) values were strikingly elevated in the immediate postoperative period. Fibrinolysis parameters showed plasminogen (PL) levels in the normal range until day 4. Antiplasmin (AP) followed a curve parallel to that of plasminogen but its levels were higher during this observation period. Similarly the initial elevation in plasminogen activator inhibitor 1 endothelial type (PAI-1) levels remained high until days 4 and 7. In summary, it can be concluded that during the postoperative phase after OLT a hypercoagulable state is developed as a result of diminished anticoagulant and fibrinolytic activity. This coagulation might be a nontechnical factor contributing to the thrombotic vascular complications of some liver recipients.

Adolescent↗
PubMed1992

Increase in the D-dimer levels during treatment in patients with acute myelogenous leukemia.

Plasma concentration of thrombin-antithrombin III complex (TAT), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), PAI-2, D-dimer complex and urokinase-plasminogen activator (u-PA) activity were studied in 30 patients with acute nonlymphoblastic leukemia (ANLL), before and during antileukemic therapy. Fifteen patients showed signs of disseminated intravascular coagulation (DIC), 10 of them classified as M3, 2 as M2 and 3 as M5 subtypes. The initial levels of TAT complex were elevated in all ANLL patients. This increase was more pronounced in patients with DIC (p less than 0.05). TAT increased significantly during the treatment period in all cases. u-PA and PAI-1 levels were elevated but there were no statistically significant differences between patients with and without DIC. PAI-2 levels were below the limit of detection in controls and in patients. However, the initially elevated D-dimer complex levels were significantly higher in DIC cases (p less than 0.01) and they increased during the treatment period. A significant and positive correlation between D-dimer and TAT complex values was found in DIC patients (r = 0.68, p less than 0.001). The high TAT complex and D-dimer levels further increased during chemotherapy treatment strongly suggest a hypercoagulable state with secondary activation of fibrinolysis not severe enough to manifest itself as clinically evident DIC in the majority of cases.

Adolescent↗
PubMed1992

Protein C, protein S and C4b-binding protein in neonatal severe infection and septic shock.

We have studied the behaviour of total protein S, free protein S, protein C and C4b-binding protein fifteen neonates with severe infections, eight with septic shock and in a group of ten healthy newborns. Protein C was decreased in shock and septic patients, but only the shock group showed significant differences compared to normal neonates. Total protein S was normal in both groups of patients, although free protein S had significantly lower values in shock and nonshock infants. C4b-binding protein was higher than normal in septic and shock patients compared to the control group. Decreased values of protein C and free protein S can be explained by the activation of coagulation and their subsequent consumption. On the other hand, the increased levels of C4b-binding protein can affect the distribution of protein S in plasma, producing a shift in protein S to the complexed inactive form. These findings can contribute to an increased risk of microthrombosis during neonatal sepsis.

Carrier Proteins↗
PubMed1992

Retroperitoneal Castleman's disease.

A case of Castleman's disease localized in the retroperitoneal space is reported. A 29-year-old patient had a mass 15 cm in diameter with radial calcification. After surgical resection, both the patient's anemia and hypergammaglobulinemia disappeared. Castleman's disease should be considered when facing a solid retroperitoneal or mesenteric mass, mainly if anemia and hypergammaglobulinemia are present. Previous reports about this unusual condition are reviewed.

Adult↗
PubMed1992

[Inflammatory pseudotumor of the liver].

Inflammatory pseudotumor is a pathological process whose cause is unknown, and whose macroscopic appearance is that of a malignant tumor, but it is in fact of inflammatory nature. Inflammatory pseudotumor of the liver is infrequent, but must be taken into account in the differential diagnosis of liver masses. A case report is presented, with review of the literature. Because of its benign nature, an aggressive approach is not recommended.

Adult↗
PubMed1991

Autologous adrenal medullary transplants in advanced Parkinson's disease with particular attention to the selective improvement in symptoms.

Ten patients with advanced Parkinson's disease, presenting with tremor, rigidity and akinesia had autologous adrenal medullary transplantation taken from the left adrenal gland to the head of the right caudate nucleus. Particular attention was taken to avoid prolonged exposure of the adrenal tissue before transplantation and to separate the medullary from the cortical adrenal tissues. Postoperative CT scans confirmed the correct position of the transplants. Differences between pre- and 1-year postoperative clinical conditions were statistically evaluated, with patients under medical (L-dopa) treatment and after the medication was temporarily discontinued. Performance of motor tasks was tested to differentiate slowness of movements imposed by excessive muscular tension (rigidity) from that secondary to delayed reaction time to sensory demands (akinesia). Two deaths occurred 35 and 69 day after surgery for causes not related to the surgical procedures. One of those patients had remained stable neurologically and the other had deteriorated to progressive dementia and catatonia. At autopsy, no lesions in the CNS other than those expected from the surgical procedure were evident, and histological examination failed to reveal chromaffin cells in the head of the right caudate nucleus. Evaluation of the 8 cases that survived for 1 year revealed no significant improvement in their clinical or motor task performance, when considered as a group. However, cases with mild akinesia did better than cases with moderate to advanced akinesia, suggesting that transplantation is indicated in cases with rigidity, but not in cases with 'negative' symptoms of Parkinson's disease. All cases required postoperative medication.

Adrenal Medulla↗
PubMed1990

Differential response to aminergic stimuli and biological behavior of growth hormone secreting pituitary adenomas.

Growth hormone (GH) serum levels in response to the administration of aminergic drugs and thyroliberine (TRH) were determined in a group of 34 acromegalics. Administration of bromocriptine (10 mg single oral dose) was followed by a decrease in GH below 60% control values in 35% of the cases. Administration of diazepam (10 mg single oral dose) to those cases not responding to bromocriptine induced a decrease in GH in 58% of the cases and an increase in GH in 42%. Administration of cyproheptadine (24 mg/day for one month) to those cases not responding to bromocriptine or with increased GH after the administration of diazepam, decreased GH in 75%, while increased GH in 25% of the cases. TRH 200 micrograms single I.V. dose induced increase of 128% GH basal level in 65% of cases (TRH positive) which correlated with more benign clinical course, decreased GH levels in response to bromocriptine, increased PRL levels, PRL-GH mixed secreting adenomas in immunohistochemistry studies, presence of granulated cells in electron microscopy studies and normalization of GH in the majority of surgically treated cases. By contrast, TRH negative cells correlated with aggressive tumor growth, lack of response to bromocriptine, normal PRL levels, pure GH secreting adenomas by immunohistochemistry, poorly granulated cells and lack of response to surgical treatment. Results suggest that there is more than one type of acromegaly that might be distinguished by the aminergic control on GH secretion.

Acromegaly↗
PubMed1990

Wakefulness-sleep modulation of EEG-EMG epileptiform activities: a quantitative study on a child with intractable epilepsia partialis continua.

Continuous all night recordings of epileptiform EEG activities from right frontal scalp and thalamic Centromedian regions and EMG activities from left deltoid muscular region were performed on a child with intractable epilepsia partialis continua, with depth stimulating-recording electrodes used for neuroaugmentive seizure control. In addition, "normal" and "mature" sleep indicators in the same child were simultaneously recorded according to the International Procedures. During wakefulness (W), type B seizures consisted of isolated, high amplitude, negative-positive EEG sharp waves recorded from the right Centromedian region (RCM sharp) correlated with isolated bursts of high amplitude EMG potentials recorded from the left deltoid muscle (LEMG jerks). Type C seizures consisted of clusters of repetitive RCM sharp and LEMG jerks, where individual EEG-EMG activities showed poor correlations. Number and amplitude of type B RCM sharp and LEMG jerks significantly decreased when patient directly shifted from W to slow wave sleep I and II (SWSI and II). Number and amplitude of RCM sharp increased while those of LEMG jerks decreased directly from SWS I and II to slow wave sleep III (SWS III); all forms of EEG-EMG epileptiform type B activities significantly decreased directly or indirectly from W and SWS to paradoxical sleep (PS). Scalp EEG spikes from right frontal and central regions showed almost parallel changes to those of RCM sharp, except during SWS II, when amplitude increased in the former and decreased in the later. Occurrence of type C seizures only decreased during PS and duration decreased directly from SWS I to II and indirectly from SWS I to SWS II and PS; and from W to SWS II and III and PS.

Child, Preschool↗
PubMed1989

[Familial deficiency of protein S associated with thrombophilia].

Protein S (SP) is a vitamin K-dependent plasma protein which acts as a cofactor of activated C protein in the inactivation of the factors Va and VIIIa; in addition, it enhances fibrinolysis by increasing the affinity of the enzyme for phospholipid surfaces. The congenital deficiency of SP is an autosomal dominant inherited trait, associated with a high risk of development of thrombotic phenomena at a relatively early age (young adults). We report a Spanish family which carried a congenital deficiency of SP associated with thrombotic complications; for its diagnosis we used the immunological quantification of the levels of free and total SP as well as the evaluation of the immunoelectrophoretic behavior of the inhibitor.

Adolescent↗
PubMed1989

Contact phase of blood coagulation in cardiogenic pulmonary oedema (CPO) and adult respiratory distress syndrome (ARDS).

In order to assess the role of the kallikreinkinin (k-k) system in the pathogenesis of pulmonary oedema, we studied the contact phase factors of blood coagulation, as well as the haemodynamics and blood gas changes in 34 patients with pulmonary oedema, 23 of them with Adult Respiratory Distress Syndrome (ARDS) and 11 with cardiogenic pulmonary oedema (CPO). We have verified significant differences in the haemodynamic pattern and blood gases between the two groups of patients, which corroborate the previously established differences between both types of pulmonary oedema. Our results reveal k-k system activation in ARDS patients, with a significant fall in factor XII (p less than 0.05), prekallikrein (p less than 0.01), alpha-2-macroglobulin (p less than 0.01) and high molecular - weight kininogens (p less than 0.005), with a rise in C1-esterase inhibitor (p less than 0.001) in comparison with patients with CPO. All of the CPO patients had normal prekallikrein levels, whereas 15 out 23 ARDS cases (65%) had decreased prekallikrein values. Our results suggest that the k-k system activation could play a role in the pathogenesis of ARDS. Estimation of prekallikrein levels may be helpful in the differential diagnosis of ARDS.

Adult↗
PubMed1989

Cyclosporin A versus methotrexate, followed by rescue with folinic acid as prophylaxis of acute graft-versus-host disease after bone marrow transplantation.

Fifty-seven patients undergoing bone marrow transplantation were randomly assigned to receive either cyclosporin A (CsA, n = 26) or methotrexate, followed by rescue with folinic acid (MTX + FA, n = 31) as prophylaxis for graft-versus-host disease (GVHD). All patients but one receiving CsA had evidence of sustained engraftment, and there was no difference between the two groups on the day in which marrow engraftment was documented. Oropharyngeal mucositis was of similar incidence and severity in the two groups. In contrast, patients receiving CsA showed higher renal and hepatic toxicity rates than those treated with MTX + FA. Severe-to-moderate acute GVHD (grades II-IV) was documented in 12 patients receiving CsA and in 12 treated with MTX + FA. The cumulative incidence of this complication was similar in both groups (46.1% and 38.7%). Similarly, there was no difference in the incidence of chronic GVHD. The leukemic relapse rates were also comparable, as well as the estimated probability of survival, which was 55% in patients treated with MTX + FA and 41% in those who were given CsA. We conclude that MTX + FA is as effective as CsA in the prevention of GVHD, with the additional advantage of reduced renal and hepatic toxicities.

Actuarial Analysis↗
PubMed1989

Intracranial studies on potential generators of some vertex auditory evoked potentials in man.

Potential generators for surface brain stem (ABSP), P200 and P300 auditory evoked potentials have been localized in patients with implanted electrodes used as an electrophysiological procedure for surgical treatment. Results suggest that surface SP and SN1-2 and components V, VI and VII of ABSP and component P3 and P300 result from specific auditory system activation, while components N1-P2 of P200 and N2-N4 of P300 result from nonspecific systems. Two subcortical generators were localized related to surface ABSP-one at the medial geniculate thalamic region (MG) related to SP and SN1 and V, VI, VII potentials, the other near the hippocampal region related to SN2. One subcortical generator related to surface N1-P2 of P200 was found near the caudal mesencephalic reticular formation, and the other two subcortical generators related to surface N2-P4 and P3 of P300 were found at the subthalamic and MG regions, respectively. Reverse polarity of some bipolar responses and lack of amplitude-latency gradients of some referential potentials at the gyrus orbitalis, rostral thalamus and anterior commissure, suggest the existence of other additional potential generators more rostrally located.

Brain↗
PubMed1989

Topographical analysis of subcortical vertex-like activities evoked by ipsi- and contralateral multimodal sensory stimulation in man.

A topographical analysis of the mesencephalic, thalamic and forebrain vertex-like activities evoked by ipsi- and contralateral somatic (SVA), visual (VVA) and auditory stimuli (AVA) was made in patients with electrodes implanted for diagnoses and treatment. Typical SVA, VVA and AVA recorded from a nonspecific polysensory system (NSS) were mainly bilateral and with similar latencies. Typical AVA to only contralateral stimuli were frequent at the ventrolateral thalamus and striatum level. In contrast, bilateral VA with different latencies and VA evoked only by ipsilateral stimuli were rare and mainly localized at the edge of the NSS. Within the NSS, typical VA to ipsi- and contralateral stimuli showed different cerebral distribution patterns according to the sensory modality stimulated, i.e. SVA showed amplitudes in response to contralateral stimuli smaller than to ipsilateral stimuli at the mesencephalic level, larger amplitudes in response to contralateral than to ipsilateral stimuli at the thalamic level and had equal amplitudes in response to contralateral and ipsilateral stimuli in the forebrain regions. VVA showed amplitudes in response to contralateral stimuli equal to those in response to ipsilateral stimuli at the mesencephalic, thalamic and forebrain levels. AVA showed amplitudes in response to contralateral stimuli equal to those in response to ipsilateral stimuli at the mesencephalic level, had amplitudes of contralateral responses larger than those of ipsilateral responses at the thalamic level and showed different amplitude combinations in the forebrain regions.

Brain↗
PubMed1989

Wakefulness-sleep modulation of the surface and depth auditory evoked potentials in man.

Amplitude and latency changes of early and late components of surface and depth auditory evoked potentials were determined during wakefulness-sleep steady state shifts in epileptic patients, with implanted electrodes used as an electrophysiological procedure for surgical treatment of temporal lobe seizures. Early surface (I and V) and depth (N8 and N15) components of the auditory brainstem potentials and late surface (P2 and N2) and depth (B and C) components of the auditory evoked potentials were produced by either 8/s or single clicks, delivered monoaurally and simultaneously recorded from the vertex and contralateral thalamic (lateral geniculate thalamic nucleus) and frontotemporal (amygdala, hippocampus and orbitofrontal cortex) regions, while patients spontaneously shifted from initial wakefulness (W1) to slow wave sleep (SWS I, II and IV), to paradoxical sleep (PS) and to final wakefulness (W2). Amplitude of late surface (P2 and N2) and depth (B and C) components significantly decreased when patients shifted from SWS IV to PS and increased from PS to W2. Latency of components P2 and B increased while that of components N2 and C decreased from SWS IV to PS. No latency changes in late components were found from PS to W2. In addition, amplitude and latency of P2 and B components significantly decreased while those of N2 and C increased from W1 to SWS IV. Polarity of all late components remained unchangeable during all wakefulness-sleep state shifts, with the exception of that of component C which reversed from W1 to SWS IV. In contrast, early surface (I and V) and depth (N8 and 15) components showed no systematic changes in amplitude and latency during all consecutive wakefulness-sleep shifts, with the exception of a significant increase amplitude but no latency of component V from PS to W1.

Epilepsy, Temporal Lobe↗