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P Marco

Publications and source records attributed to P Marco.

At least 37 records · Page 2Linked to original sources
PubMed1996

Distribution of parvalbumin immunoreactivity in the neocortex of hypothyroid adult rats.

Early hypothyroidism produces a generalized damage in the brain and in particular, changes in the connectivity of neocortical sensory areas. In this paper, the potential alterations in local neocortical circuits have been explored using immunocytochemistry for parvalbumin (PV) in normal and hypothyroid adult rats. The number and radial distribution of PV-positive cells were similar in both groups, but in hypothyroid rats, the density of PV-positive terminal-like puncta and processes was dramatically reduced, especially in layers II-III and the lower part of layers IV-V and VI. These results suggest that thyroid hormones are necessary for normal development of cortical circuits in which PV-positive cells are involved.

Animals↗
PubMed1996

Inhibitory neurons in the human epileptogenic temporal neocortex. An immunocytochemical study.

Immunocytochemical methods were used to study alterations in inhibitory neuronal circuits in human neocortex resected during surgical treatment of intractable temporal epilepsy associated or not with brain tumours. The epileptogenic cortex was characterized and divided into spiking or non-spiking zones by intraoperative electrocorticography (ECOG). The resected cortex was cut into blocks, sectioned and stained immunocytochemically for visualization of glutamic acid decarboxylase (GAD), the calcium-binding protein, parvalbumin (PV) and glial fibrillary acidic protein (GFAP). A variety of alterations in cortical neuronal circuits as revealed by immunocytochemical and histological methods were found. Similar alterations in inhibitory neuronal circuits appear to occur independently of the primary epileptogenic site and pathology associated with epilepsy, which suggests that there is possibly a common basic underlying mechanism that leads to seizure activity. These changes were apparently unrelated to ECOG findings at surgery, which bring into question the value of the use of interictal epileptic discharges recorded by ECOG to guide cortical resections. The most conspicuous and common change was the loss of chandelier cells. The finding that these cells are among the most vulnerable types of GABAergic interneurons in the epileptogenic temporal cortex indicates that they might be of great functional importance, since the axon terminals of chandelier cells are likely to exert powerful regulation of impulse generation in cortical pyramidal cells. Therefore, these cells might represent a key component in the aetiology of human epilepsy.

Adolescent↗
PubMed1996

Quantification of circulating activated protein C in human plasma by immunoassays--enzyme levels are proportional to total protein C levels.

We have developed a simple assay that measures the circulating activated protein C (APC) in plasma. The assay requires collection of duplicate blood samples, one in citrate plus heparin and the other in citrate plus inhibitors of the enzyme. In the heparin tube, APC reacts completely and irreversibly with its major plasma inhibitors, protein C inhibitor (PCI) and alpha 1-antitrypsin (alpha 1AT), and the complexes formed are measured by ELISAs. The amount of circulating APC is calculated from the difference between the total amount of complexed APC (sample in citrate plus heparin) and the amount of APC complexed in vivo (sample in citrate plus inhibitor). Over 95% of the APC added to blood collected with heparin was recovered in the assay. The assay can easily be performed in four hours, and had a detection limit of 0.1 ng/ml APC. The mean APC level in 18 protein C heterozygous members from seven kindreds was significantly lower (0.6 +/- 0.3 ng/ml) than in 20 healthy controls (1.1 +/- 0.3 ng/ml) (p < 0.001), whereas the mean level in 10 non-affected members from the kindreds studied was 1.5 +/- 0.3 ng/ml. In the group of 12 nonanticoagulated heterozygous protein C-deficient individuals, the three patients with a history of venous thrombosis had a mean APC level significantly lower than the nine asymptomatic members (p < 0.01), both subgroups showing similar protein C levels. There was a significant correlation in all groups between the levels of APC and the levels of protein C antigen (r = 0.758, p < 0.0001) and activity (r = 0.745, p < 0.0001), which means that APC circulating levels are proportional to protein C levels and suggests that the protein C level is the limiting factor in the rate of protein C activation in vivo.

Adolescent↗
PubMed1996

[The fibrinolytic system in patients with dilated myocardiopathy].

OBJECTIVES: To study the fibrinolytic system in dilated cardiomyopathy (DCM) patients, and the relationship between the degree of severity (NYHA degree), and the presence of complications (atrial fibrillation, intracavity thrombus, and peripheral embolism). We also analyzed the influence of the antithrombotic therapy on the fibrinolysis's proteins. PATIENTS AND METHODS: We included 18 patients, stratified in two etiologic groups: 9 with idiopathic and 9 with ethyl DCM. The fibrinolytic system was investigated through the plasma levels of antigenic and functional t-PA and PAI-1. We also carried out a venous occlusion test to investigate the fibrinolytic the fibrinolytic activity in t-PA secretion. The clinical aspects were recorded. We included 30 healthy individuals matched for age and sex, as controls. RESULTS: The antigenic levels of t-PA and PAI-1, were significantly higher in the DCM group than in the control group (p < 0.01). The venous occlusion test responses were normal. No relationship between the fibrinolytic parameters and clinical data were observed. DISCUSSION: The high levels of antigenic t-PA found in DCM patients were considered as a vascular injury marker, and a atherothrombotic risk factor. Furthermore, there is a hypofibrinolytic condition shown by a PAI-1 augmentation. In conclusion, we are prone to consider long term oral anticoagulation in the management of DCM patients.

Adult↗
PubMed1995

The role of antiphospholipid antibodies in lupus nephropathy.

Although several clinical and morphological changes observed in overt systemic lupus erythematosus have been associated with the presence of antiphospholipid antibodies (aPL), the relation between these antibodies and lupus nephropathy (LN) is not clear. Twenty-three patients with biopsyproved LN were retrospectively studied (average age 28.5 +/- 12.3 years, all women) in order to investigate the relationship between the presence of aPL and clinical and immunobiological data. The average follow-up period was 55 +/- 42 months. The presence of aPL (IgG and IgM) was detected at least once in all patients by ELISA and/or lupus anticoagulant (kaolin time). Seven patients (30.4%) were aPL+, and the remainder aPL-. We did not find differences related to age, period of follow-up, blood pressure and livedo reticularis. However the prevalence of thrombosis, strokes and hemolysis was slightly higher in the aPL+ patients. The levels of antinuclear antibodies or anti-DNA antibodies, immunoglobulins and complement serum levels (C3, C4) were also similar in both groups. In the aPL+ group, proteinuria was significantly higher than in aPL- cases (2.21 +/- 1.5 and 0.91 +/- 1.07 g/24 h, respectively; p = 0.029). The renal histological pattern in both series was similar. However, microthrombosis in the glomerular capillary lumens was more frequent in the aPL+ group. The evolution of renal function was less favorable in aPL+ patients when compared with aPL- patients. We conclude that the presence of aPL in patients with LN is associated with several characteristics of renal impairment which may contribute to its evolution.

Adult↗
PubMed1995

[Botryoid rhabdomyosarcoma of the nasopharynx treated with chemotherapy only. Survival lasting more than ten years].

The progress of Rahbdomyosarcoma (RMS) of the nasopharynx succeed frequently as infiltrative and destructive form to the base of the skull, in which case its prognostic is worse as when localized somewhere else. We report the case of a RMS in a 4-year-old child. The tumour infiltrating the base of the skull (stage III), was treated with chemotherapy only because the neighbourhood of the sella turcica and the pituitary gland strongly forbids the appeal to radiotherapy, in order to avoid untoward side-effects on this gland and also upon the growth of the child. At present, 10 years after, he remains asymptomatic and free of the tumour. Computered tomography has probe to be the best way to study the site and the extent of this growth and even the control of course of treatment.

Child, Preschool↗
PubMed1995

[Antiphospholipid antibodies in women with habitual abortions. Treatment with prednisone and acetylsalicylic acid during pregnancy].

PURPOSE: To discover the prevalence of antiphospholipid antibodies in women with a history of repeated miscarriages. Therapy evaluation of aspirin and prednisone to achieve living term foetus from women in whom antiphospholipid antibodies had been detected and who had become pregnant again. PATIENTS AND METHODS: 82 consecutive women with history of at least of two miscarriages, with no live foetus in either case. 14 women positive for antiphospholipid antibodies who had become pregnant again (group of therapy evaluation), were treated with aspirin (125 mg/d) and prednisone (20 mg/d). 60 normal pregnant women (control group). Lupus anticoagulant evaluation: APTT tests caolin clotting time and APTT system neutralized with platelet phospholipids. Antiphospholipid antibodies: ELISA test. RESULTS: 13.4% were positive to antiphospholipid antibodies (ELISA), and 2.4% were positive in both positive in both test. Therapy evaluation: 75.5% (11 cases) of pregnancies were successful (normal foetus), 14% (2 cases) of fetal losses, and 7% (1 case) of foetal malformations (acranius). CONCLUSIONS: In our study the antiphospholipid antibodies represent one of the main causes of repeated foetal losses. We recommended in cases of infertile women to test for antiphospholipid antibodies regularly. We confirm the effectiveness of the therapy (aspirin and prednisone) in achieving successful pregnancies in patients with a history of infertility.

Abortion, Habitual↗
PubMed1992

[Cases of tetanus in Guipuzcoa].

In order to evaluate the situation of tetanus in Guipúzcoa and to assess the impact of preventive measures, we studied the incidence, mortality and other aspects of the disease during the past three decades. Ninety eight cases were detected (annual average 3,27 SD 2,6), this figure being reduced over time (7,2 cases per year during the period 1962-1966; 1,8 cases per year between 1987 and 1991). 67,3% were men and 32,7% women. We registered 6 cases of neonatal tetanus, all of them prior to 1976. Since 1969, there has been no cases within the 1-14 age group. Half of the cases detected during the last five years (4/9) were intravenously drug-addicts. Among those living in less populated areas (less than 10.000 population), the risk of developing the disease was four times greater. 33,7% of patients died, being the mortality rate higher among newborns and patients died, and patients over 55. Although the situation was not worse than in other similar environments, the incidence of tetanus should be reduced by reinforcing preventive measures.

Adolescent↗
PubMed1991

Steroids in Duchenne muscular dystrophy--deflazacort trial.

We conducted a double blind controlled trial in 28 Duchenne muscular dystrophy (DMD) patients with Deflazacort (DF), an oxazoline derivative of prednisolone which reduces its side-effects. Myometric muscle strength measurements, Scott Score and timed tests showed statistically significant improvement for the treated group (P less than 0.05). Side-effects after 9 months of treatment included mild cushingoid appearance in four patients (28%) and moderate in only one (7%), increased appetite in seven (50%), increased body hair in four (28%), irritability and hyperactivity in three (21%). Increased body weight was not prominent and was controlled with dietary measures. No patient had to be withdrawn from medication. More research and long-term follow-up are needed in order to establish the mechanism of improvement and the consequences of long-term steroid administration in DMD. In this regard DF appears as an alternative to prednisone preserving its benefits but with fewer side-effects.

Anti-Inflammatory Agents↗
PubMedDate not supplied

Selective changes in the microorganization of the human epileptogenic neocortex revealed by parvalbumin immunoreactivity.

The microanatomy of the human lateral temporal cortex removed from patients with intractable temporal lobe epilepsy was studied using correlative light and electron microscopic immunocytochemical methods for the localization of the calcium-binding protein parvalbumin (PV). PV immunostaining was mainly used to label a subpopulation of powerful cortical inhibitory interneurons that have been shown to be lost at epileptic foci in certain animal models of epilepsy. In the human neocortex with normal appearance, we identified the same local neuronal circuitry as in the normal monkey cortex, but in some regions of the same cortex, a fine disorganization of neuronal circuits (loss of inhibitory neurons and presumptive thalamocortical terminals) was found. This abnormal circuitry may interfere with normal cerebral activity in epileptic patients. These results also indicate that PV immunoreactivity can be a useful tool to study normal and abnormal synaptic circuits in the human cerebral cortex.

Adolescent↗
PubMedDate not supplied

Inhibitory synaptogenesis in mouse somatosensory cortex.

It is widely believed that inhibitory synapses are not present or present in only small numbers in the rodent cerebral cortex during the early postnatal period when the cortex is being innervated by thalamocortical fibers. Quantitative electron microscopy was carried out on the posteromedial barrel subfield of mouse somatosensory cortex from postnatal day 4 (P4) when thalamocortical innervation of the barrels is becoming established, through to sexual maturity (>P32), and in adulthood. Both asymmetrical (putatively excitatory) and symmetrical (putatively inhibitory) synapses were present in all layers from P4. The symmetrical synapses were immunoreactive for GABA at all ages. There was a progressive increase in both asymmetrical and symmetrical synapses up to P32, density in all layers increasing 16-fold, with the production of asymmetrical synapses leading and greatly outstripping that of symmetrical. From P32 to P120, the oldest age studied, synaptic numbers declined by 18% to 13 times the P4 level, but this affected predominantly layers II/III, IV and V, and mainly involved asymmetrical synapses. The relative percentage of asymmetrical to symmetrical synapses from P4 to P8 was 57%/43% but at P32 it was 89.5%/10.5% and in adulthood 85.4%/14.6%. These data indicate that inhibitory synaptogenesis in the rodent cortex begins earlier than previously thought, a basis for inhibition being present from the earliest period. Pruning of all synapses occurs well after thalamocortical innervation is established and inhibitory synapses are less affected by the pruning process.

Aging↗
PubMedDate not supplied

Estimation of the number of synapses in the cerebral cortex: methodological considerations.

In the present work we discuss several sampling procedures commonly used for counting synapses in the cerebral cortex. We compare, within the same tissue, two frequently used sterereological methods for determining the numerical density of synapses per unit volume, using as an example the estimation of the number of types of synapses by layers in the neuropil of the adult human temporal neocortex. These two methods are a size-frequency method (formula N(A)/d) and the disector method (sigmaQ-/a x h). Since the size-frequency method is assumption-based and the disector method is considered to be an unbiased method, the latter is often recommended for the quantification of synapses and other objects. We obtained, however, similar estimates for the numerical density of the different types of synapses using both methods, although they presented different technical difficulties and statistical properties. In addition, we show that the size-frequency method is more efficient and easier to apply than the disector method. Nevertheless, there are other methods for quantification which may also be valid, depending on the aim of the research; but the data reported in many articles are often complicated, which makes it very difficult for the reader to follow all the steps of the calculation. If certain basic information were given, this would facilitate the interpretation and sharing of important information with other laboratories, regardless of the method used for quantification. Finally, based on our present results and previous literature, we propose a simple general protocol for estimating the numerical synaptic density by volume in the neuropil of the cerebral cortex.

Adult↗
PubMedDate not supplied

Anticoagulant therapy modifies fibrinolytic dysfunction in chronic atrial fibrillation.

OBJECTIVE: We evaluated the changes in fibrinolytic activation markers before starting anticoagulation, at 1 and 6 months following the introduction of anticoagulant therapy. DESIGN AND METHODS: Tissue plasminogen activator (t-PA), its endothelial inhibitor (PAI-1), plasmin:antiplasmin complexes (PAPc), modified antithrombin III (ATM), D dimer (D-D) and fibrinogen (FIB) were measured in 36 patients with chronic atrial fibrillation. Fifteen of them had rheumatic mitral stenosis and 21 had nonrheumatic atrial fibrillation. Basal levels were compared with a sex- and age-matched healthy control group. RESULTS: At baseline, patients with atrial fibrillation showed significantly higher plasma levels of PAI-1, ATM, D-D and FIB levels (p < 0.05) than controls, and no differences in t-PA and PAPc concentrations. Levels of t-PA, PAI-1, ATM and D-D decreased significantly under anticoagulant therapy, whereas FIB levels were not significantly modified. PAPc levels were significantly increased at 6 months in the rheumatic group but did not differ significantly in the nonrheumatic group. CONCLUSIONS: Patients with chronic atrial fibrillation show a hypercoagulant state and a relatively low fibrinolytic function. After 6 months of anticoagulant therapy, an improvement in fibrinolytic function markers was detected.

Aged↗