Biomedical subjects

M G Campos

Publications and source records attributed to M G Campos.

At least 19 recordsLinked to original sources

PubMed1997

Inhibitory effect of sex steroids on guinea-pig airway smooth muscle contractions.

We assessed the possible inhibition of airway smooth muscle contraction by progesterone and pregnanolones (5 alpha and 5 beta-reduced). Progesterone and 5 beta-pregnanolone prevented histamine- or carbachol-induced contraction in isolated guinea-pig trachea and potency was related to their respective chemical structure; progesterone was the most potent inhibitor in a concentration-dependent manner. The steroids also exhibited calcium antagonist activities in this tissue as assessed by their action on calcium entry in depolarized preparations; this event involved the immediate blockade of the extracellular calcium influx in the muscle cell membrane, indicating a nongenomic action. Classical GABAA antagonists did not block the progesterone response, implying no involvement of the GABAA-receptor complex. Our results suggest a bronchodilating effect induced by sex steroids, and probably by other related compounds, before the genomic mechanisms take place. This nongenomic action of steroids could have potential therapeutic usefulness in the treatment of asthma.

Animals↗

PubMed1997

Surgical treatment of neoplasms associated with medically intractable epilepsy.

OBJECTIVE: Surgical treatment in patients with brain tumors and medically intractable epilepsy is aimed at the removal of the neoplasm and complete seizure control. However, an adequate surgical approach is still controversial. This study was designed to analyze the factors for the optimum surgical treatment of these patients. METHODS: The clinical, electrophysiological, operative, and histopathological data of 146 consecutive patients who underwent surgery between November 1987 and May 1995 for intrinsic brain tumors and pharmacoresistant epilepsy were evaluated. RESULTS: The majority of the tumors were located in the temporal lobe (n = 116) and involved the cortical gray matter. The most frequent tumors were gangliogliomas (n = 65), pilocytic astrocytomas (n = 21), and dysembryoplastic neuroepithelial tumors (n = 19). All but three tumors (98%) were of low histopathological grade (World Health Organization Grades I or II). The biological behavior of the tumors was strikingly indolent, as indicated by a long preoperative history of chronic seizures (mean, 14 yr). In all cases, complete resection of the tumor, including the epileptogenic area (as determined by noninvasive and/or invasive recordings of the zone of seizure onset and persistent interictal activity), was intended. Complications were encountered in 11 cases (8%). However, no patient died and there was no permanent morbidity. Of the 124 patients who had postoperative follow-up examinations more than 6 months after resection, 71% were seizure-free, 11% had no more than two seizures per year, 13% showed a reduction of seizure frequency of at least 75%, and 5% had no appreciable reduction in seizure frequency. CONCLUSION: The data indicate that neoplasms associated with medically intractable epilepsy constitute a distinct clinicopathological group of tumors that arise in young hosts, involve the cortex, and exhibit indolent biological behavior for many years. Complete surgical removal of these tumors, including the epileptogenic area, can achieve excellent seizure control.

Adolescent↗

PubMed1997

Identification of neutrophil chemotactic factors in bronchoalveolar lavage fluid of asthmatic patients.

BACKGROUND: Although neutrophils have been implicated in bronchial asthma, the mechanism(s) which bring these cells into the airways is poorly understood. OBJECTIVE: To investigate the presence and identity of neutrophil chemotactic factors in bronchoalveolar lavage (BAL) fluid from atopic asthmatic subjects. METHOD: BAL fluid was obtained from 13 subjects (seven asthmatics and six normals), aged 19 to 60 yr, at bronchoscopy. Separation of neutrophil chemotactic activity (NCA) was achieved by FPLC cation exchange chromatography. Fractions were collected and assayed for chemotaxis in multiwell micro-chemotaxes chambers using polycarbonate filters, for the complement peptide C5a/C5a des Arg by radioimmunoassay (RIA) and for interleukin-8 (IL-8) by ELISA. RESULTS: NCA was found in FPLC fractions of BAL samples in four out of seven asthmatics and each of these subjects had at least three similar peaks of NCA. The major peak of NCA was found to contain immunoreactive C5a/C5a des Arg and chemotaxis. In response to this NCA could be blocked by desensitization of the neutrophils with recombinant C5a. Purified serum derived C5a/C5a des Arg was found to have altered chromatographic properties when added to BAL fluid; this suggested that BAL fluid contained proteins which interacted with the C5a/C5a des Arg. Immunoreactive IL-8 (iIL-8) was also detected but its concentration or chemical form was insufficient to induce neutrophil chemotaxis. CONCLUSION: This study demonstrates that bronchial asthmatic lavage fluid contains C5a/ C5a des/Arg and IL-8, together with other as yet unidentified factors which may contribute to neutrophil recruitment in this disease.

Adolescent↗

PubMed1996

Role of endothelium in the vasodilating effect of progestins and androgens on the rat thoracic aorta.

1. In the rat thoracic aorta, contractions induced by noradrenaline were inhibited by the steroids progesterone, pregnanolone, testosterone and 5 alpha- and 5 beta-dihydrotestosterone. 2. Removal of endothelium did not prevent relaxation to the steroids, suggesting that the vasodilating effect of steroids occurred on the smooth muscle cells. 3. gamma-Aminobutyric acid (GABA) did not modify noradrenaline-induced contraction. Thus, the vasodilation elicited by steroids is not apparently mediated by GABA receptors. 4. On the basis that noradrenaline opens receptor-operated calcium channels to induce contraction, we suggest that relaxation by steroids involves a blockade of this type of channels.

Androgens↗

PubMed1996

Surgical treatment of extratemporal epilepsy: clinical, radiologic, and histopathologic findings in 60 patients.

PURPOSE AND METHODS: The aim of this study was to analyze clinical, radiologic, and histopathologic findings in 60 consecutive patients with medically intractable extratemporal epilepsy who were operated on between November 1987 and May 1993. RESULTS: Histologically, there were distinct structural abnormalities in 50 (83%) of the surgical specimens. Signal abnormalities on magnetic resonance imaging (MRI) were present in all patients with neoplastic lesions (n = 17) and in 94% of patients with nonneoplastic focal lesions (n = 32). Overall, structural abnormalities were detected by MRI in 47 (96%) of 49 patients with focal lesions. During a mean follow-up of 4 years, 30 (54%) patients remained completely seizure free, 11 (20%) had < or = 2 seizures per year, seven (12%) showed a seizure reduction of > or = 75%, and eight (14%) had < 75% reduction in seizure frequency. The fraction of seizure-free patients was 12 (80%) of 15 in patients with neoplastic lesions, 16 (52%) of 31 in patients with nonneoplastic focal lesions, and two (20%) of 10 for those without histopathologic abnormalities. The differences in seizure outcome between patients with and without focal lesions were statistically significant (p < 0.05), if seizure-free outcome was compared with persistent seizures. CONCLUSIONS: Focal lesions and particularly neoplasms are associated with improved postoperative seizure control compared with patients without histopathologic abnormalities. We advise caution in considering surgery to treat extratemporal epilepsy in patients who have normal MRI scans, because the outcome with the approach described in this study is poor in such cases.

Adolescent↗

PubMed1996

Dysembryoplastic neuroepithelial tumors: MR and CT evaluation.

PURPOSE: To evaluate dysembryoplastic neuroepithelial tumors (DNTs) on MR and CT studies and to compare DNT with other frequently encountered epileptogenic glioneuronal lesions. METHODS: We analyzed the MR images and CT scans of 16 patients who had complex partial epilepsy and DNT with respect to tumor location, size, CT density, MR signal intensity, mass effect, contrast enhancement, and heterogeneity, and compared these features with CT and MR findings in 51 cases of ganglioglioma and 33 cases of glioneuronal malformation. RESULTS: DNTs were located in the temporal lobe in 14 patients and in the frontal lobe in 2 patients. The cortex was involved in all cases and the subcortical white matter in 10 cases. Fifty percent of the tumors had poorly defined contours. On MR images, 14 DNTs had multiple cysts and 2 had single cysts. Contrast enhancement was observed in 6 DNTs, and mass effect was present in 9. CT scans disclosed moderately hypodense lesions in 7 patients and markedly hypodense cystic lesions in 6 patients. Two DNTs were calcified. Tumor hemorrhage with perifocal edema was observed in 1 case. Contrary to previous reports, slow but definite tumor growth was present during a 13-year period in 2 of 6 patients in whom serial CT or MR studies were obtained. CONCLUSION: A multicystic appearance on MR images is a characteristic feature of DNT and corresponds to its myxoid matrix and multinodular architecture. This feature is rare in gangliogliomas and glioneuronal malformations, and, as such, may help differentiate DNTs from these disorders.

Adolescent↗

PubMed1995

Inhaled Bordetella pertussis vaccine decreases airway responsiveness in guinea pigs.

Bordetella pertussis (BP) has been used as adjuvant for experimental animal immunization, but its effects on airway responsiveness are uncertain. Three groups of guinea pigs were used: animals with a single exposure to inhaled BP vaccine (strain 134, total dose 1.24 x 10(12) germs), animals submitted to a sensitization procedure through inhalation of ovalbumin plus BP, and healthy control animals. Four weeks after inhalation of BP or after the beginning of sensitization, dose- or concentration-response curves to histamine were constructed in vivo and in vitro (tracheal and parenchymal preparations). We found that BP alone produced lower responses to histamine than control guinea pigs in vivo (insufflation pressure, p = 0.0003) and in tracheal tissues (p = 0.04), but not in parenchymal preparations. Sensitization did not modify the responsiveness compared with their respective controls. These results suggest that some BP component(s), probably pertussis toxin, causes a long lasting airway hyporesponsiveness in guinea pigs.

Adjuvants, Immunologic↗

PubMed1995

Surgical treatment of temporal lobe epilepsy: clinical, radiological, and histopathological findings in 178 patients.

The surgical treatment of pharmacoresistant temporal lobe epilepsy is increasing rapidly. The correlation of preoperative MRI, histopathological findings, and postoperative seizure control is reported for 178 patients with chronic medically intractable temporal lobe epilepsy who were operated on between November 1987 and January 1993. Histopathologically there were distinct structural abnormalities in 97.2% of the surgical specimens. Signal abnormalities on MRI were present in 98.7% of patients with neoplastic lesions (n = 79), 76.6% of patients with non-neoplastic focal lesions (n = 55), and 69.2% of patients with Ammon's horn sclerosis (n = 39). Overall, structural abnormalities were detected by MRI in 82.7% of all patients. The mean postoperative follow up period was three years. Some 92% of the patients benefited from surgery: 103 patients (61.7%) were seizure free, 26 (15.5%) had no more than two seizures a year, and 24 (14.4%) showed a reduction of seizure frequency of at least 75%. Fourteen patients (8.4%) had a < 75% reduction of seizure frequency. The percentage of patients who were completely free of seizures after operation was 68.5% for patients with neoplastic lesions, 66.7% for Ammon's horn sclerosis, and 54.0% for patients with non-neoplastic focal lesions. By contrast, none of the patients in whom histopathological findings were normal became seizure free postoperatively. The data show that the presence of focal lesions or Ammon's horn sclerosis as determined by histopathological examination is associated with improved postoperative seizure control compared with patients without specific pathological findings. Brain MRI was very sensitive in detecting neoplasms; however, its sensitivity and specificity were limited with respect to non-neoplastic focal lesions and Ammon's horn sclerosis. Improvement of imaging techniques may provide a more precise definition of structural lesions in these cases and facilitate limited surgical resections of the epileptogenic area rather than standardised anatomical resections.

Adolescent↗

PubMed1995

Vanadate-induced potentiation of smooth muscle contractility in the rat depolarized uterus.

The effect of ortho-vanadate on Ca(2+)-influx in the uterine smooth muscle was investigated. Orthovanadate (10-300 microM) gradually increased the muscular tone of rat isolated uterus bathed in a high K+ (30 mM)-low Ca2+ (0.15 mM) solution. This response was blocked by nifedipine (10 nM) and reproduced by BAY K 8644 (3-300 nM). Atropine and indomethacin were unable to block the effects induced by vanadate and BAY K 8644. Cumulative addition of CaCl2 to the tissue bathed in a depolarized solution without CaCl2 produced a graded tonic response that was potentiated by either vanadate (30 microM) or BAY K 8644 (30 nM), and inhibited by nifedipine. Neither vanadate (30 microM) nor BAY K 8644 (30 nM) modified the uterine tone of tissues immersed in the depolarizing solution without CaCl2. It is concluded that vanadate-induced contraction of rat uterine smooth muscle involves Ca(2+)-influx from the extracellular medium to the myometrial cell. Vanadate might act as a Ca(2+)-channel activator, similar to BAY K8644.

Animals↗

PubMed1994

Anaplastic ganglioglioma: case report and review of the literature.

We present the case of a 13-year-old boy who had a 12 year history of complex partial seizures. Recent CT scan and Magnetic Resonance Imaging (MRI) showed a contrast-enhancing lesion of the left temporal lobe, while CT performed 6 years ago was unconspicuous. Extended lesionectomy was performed according to the results of presurgical epileptological evaluation. Histological examination of the specimen showed an anaplastic ganglioglioma (WHO grade III). The clinical, neuroradiological, and histopathological findings of our patient are presented with respect to the literature on malignant gangliogliomas.

Adolescent↗

PubMed1994

Effect of ozone exposure on antigen-induced airway hyperresponsiveness in guinea pigs.

Airway hyperresponsiveness can be induced by several stimuli including antigen and ozone, both of which may be present in the air of polluted cities. Though the effect of ozone on the bronchoconstrictor response to antigen has been well described, the combined effect of these stimuli on airway hyperresponsiveness has not yet been studied. Sensitized guinea pigs with or without ozone exposure for 1 h at 3 ppm, 18 h prior to study, were challenged with a dose-response curve to histamine (0.01-1.8 micrograms/kg, iv) followed by an antigen challenge (ovalbumin, 50 micrograms/kg, iv), and then by a second histamine dose-response curve 1 h later. Airway responses were measured as the increase in pulmonary insufflation pressure. In sensitized guinea pigs, the histamine ED50 significantly decreased after antigen challenge, demonstrating the development of airway hyperresponsiveness. Sensitized guinea pigs exposed to ozone showed airway hyperresponsiveness to histamine when compared with nonexposed animals, and such hyperresponsiveness was further enhanced after antigen challenge. We conclude that in this guinea pig model of acute allergic bronchoconstriction both antigen challenge and ozone induce airway hyperresponsiveness, while ozone exposure does not modify the development of antigen-induced hyperresponsiveness.

Acute Disease↗

PubMed1994

Gangliogliomas: clinical, radiological, and histopathological findings in 51 patients.

Clinical, radiological, and histopathological features of 51 surgically treated gangliogliomas were evaluated retrospectively. The most common presenting symptoms were epileptic seizures (47 patients (92%)). Focal neurological deficits occurred in 8% of the patients. The duration of symptoms at the time of operation ranged from three months to 45 years, mean 11 years. The temporal lobe was affected in 43 patients (84%), the frontal lobe in five patients (10%), and the occipital lobe in one patient (2%). Two of the tumours (4%) were localised infratentorially. On MRI, solid tumour parts usually showed a pronounced signal increase on proton density images and a less pronounced signal increase on T2 weighted images, whereas solid components were mainly isointense on T1 weighted images. Contrast enhancement was noted in 16 of 36 patients (44%). Cystic tumour parts were found in 23 of 40 patients (57%), all characterised by signal increase on T2 weighted images and decreased T1 signals. Signal deviation of cystic tumour parts on proton density images was variable. Computed tomography was performed in 17 patients and showed hypodense lesions in 10 (59%), and calcifications in seven (41%) cases. Surgery included complete tumour removal in 44 patients (86%) and partial resection in seven (14%). In six patients (12%) there were transient postoperative complications. One patient (2%) died postoperatively due to pulmonary embolism. Histopathological examination of the surgical specimens showed low grade gangliogliomas in 49 cases (96%) and anaplastic gangliogliomas in two (4%). Control MRI of 31 patients with a mean follow up period of 16 months was uneventful in all but one case of an anaplastic ganglioglioma. In all patients in whom the ganglioglioma was associated with medically intractable seizures the operation resulted in complete relief of seizures or a noticeable improvement of the epilepsy.

Adolescent↗

PubMed1994

Role of eosinophil activation in the bronchial reactivity of allergic guinea pigs.

Ovalbumin inhalation by sensitized guinea pigs induced a marked increase in the number of eosinophils (0.89 +/- 0.18 to 5.45 +/- 0.77 x 10(5)/ml, n = 10, p < 0.05) and elevations in the amounts of protein and eosinophil-derived major basic protein (MBP) (1,010.7 +/- 184.9 to 4,116.6 +/- 973.0 ng/ml, n = 10, p < 0.05) recovered by bronchoalveolar lavage (BAL). In contrast, no changes in the levels of eosinophil peroxidase (EPO) or in the sensitivity of the airways to bronchoconstriction induced by methacholine were detected. However, when ovalbumin-exposed guinea pigs received an intratracheal instillation of 1 microgram leukotriene (LT)B4 30 min prior to methacholine provocation, elevated levels of EPO and MBP in the BAL fluid and a marked bronchial hyperreactivity to methacholine were noted when compared with saline-challenged LTB4-injected animals (p < 0.05). In contrast, the intratracheal instillation of 1 or 3 micrograms platelet-activating factor (PAF) did not significantly modify the bronchial reactivity to methacholine or the levels of EPO and MBP. PAF and LTB4 induced similar enhancements in the amount of protein in BAL fluids from antigen-exposed guinea pigs, suggesting that increased endothelial/epithelial permeability does not account for hyperreactivity. A significant correlation between the levels of EPO or MBP and the intensity of the bronchial responsiveness to methacholine were shown in ovalbumin-challenged guinea pigs, irrespective of their subsequent treatment, i.e., either with PAF or with LTB4 or with their vehicle (r = 0.579, p = 0.0002 and r = 0.330, p = 0.049, n = 36 for EPO and MBP, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

[Morphological findings in temporal lobe epilepsy: experience with 216 consecutive surgical specimens].

We have examined 216 consecutive surgical specimens of patients with chronic pharmacoresistant temporal lobe epilepsy. Neoplasms were detected in 75 cases (34.7%). All but two of these tumors were of low histopathological grade (WHO-grade I or II). There were 34 gangliogliomas, 17 pilocytic astrocytomas, 9 oligodendrogliomas, 6 fibrillary astrocytomas, and 6 dysembryoplastic neuroepithelial tumors. Fifty-one specimens contained non-neoplastic focal lesions and an additional 13 cases had both tumors and non-neoplastic focal lesions within the same specimen. The most frequent non-neoplastic focal lesions were microscopic glioneuronal hamartias (32 cases), glioneuronal hamartomas (7 cases) and vascular malformations (13 cases). The hippocampal formation was structurally well preserved in 71 specimens and in 51 of these (71.8%) there was Ammon's horn sclerosis. The findings document that intractable temporal lobe epilepsy is associated with significant structural alterations in the great majority of patients.

Brain Neoplasms↗

PubMed1994

[Surgery for epilepsy].

Surgical treatment of epilepsy is reserved for patients refractory to maximal doses of antiepileptic drugs. The success of surgery depends on the pre-surgical diagnosis, that is based in clinical history, neurological examination, electroencephalography, neuropsychological examination, Wada test and neuro imaging (basically magnetic resonance). In this way, the epileptogenic focus is precisely located and unsuspected accompanying lesions are frequently detected. The surgical procedure consist in the removal of the epileptogenic focus and the associated brain lesions (usually present). The most frequent procedures are over the temporal lobe (75%) and secondly the epileptogenic focus removal. Less frequent procedures are hemispherectomies and callosotomies. Organic lesions such as low malignancy grade tumors, embryonic developmental failures, hippocampal sclerosis are associated to temporal epilepsy in up to 80% of cases. Ninety percent of patients get rid or have a significant reduction in seizures after surgery and 10% do not experience changes.

Corpus Callosum↗

PubMed1994

Estrogenic actions of norethisterone and its A-ring reduced metabolites. Induction of in vitro uterine sensitivity to serotonin.

The estrogen-like effects of norethisterone (NET) seem to be mediated by the interaction of 3 beta 5 alpha- and 3 alpha 5 alpha-tetrahydronorethisterone (3 beta 5 alpha- and 3 alpha 5 alpha-NET, respectively) with the estrogen receptor. Considering that the in vitro uterine contractile response to serotonin (5-HT) is specifically dependent on estrogen, the aim of the present study was to investigate whether NET and its A-ring reduced metabolites administered in vivo to ovariectomized rats induce uterine sensitivity to 5-HT in vitro. The administration of 3 beta NET in vivo, which is the NET metabolite with the highest affinity for the estrogen receptor, induced a maximal contractile response to serotonin similar to that of 17 beta-estradiol treatment. The other metabolites induced less uterine activity. According to the effective dose 50, the order of estrogenic potency was 17 beta-estradiol > 3 beta 5 alpha NET > 3 alpha 5 alpha NET > NET > 5 alpha NET. The estrogenic effect of 3 beta 5 alpha- and 3 alpha 5 alpha NET may be exerted through their interaction with the estrogen receptor, whereas NET and 5 alpha NET, which do not bind to the estrogen receptor and display a minor estrogenic activity, require prior bioconversion to 3 beta 5 alpha NET and perhaps to 3 alpha 5 alpha NET. The A-ring reduced metabolites of NET, mainly the 3 beta 5 alpha NET, may be exerting estrogenic responses and modulating uterine activity when administered in vivo.

Animals↗

PubMed1993

Surgical pathology of chronic epileptic seizure disorders: experience with 63 specimens from extratemporal corticectomies, lobectomies and functional hemispherectomies.

The surgical treatment of chronic pharmacoresistant epilepsies is increasing rapidly. Although several studies have reported on histopathological findings in temporal lobe epilepsy, little is known about the surgical pathology of other seizure disorders. Here we report the histopathological findings in 63 consecutive surgical specimens of patients who were operated for chronic pharmacoresistant epileptic seizures other than temporal lobe epilepsy (37 corticectomies, 19 functional hemispherectomies, 5 lobectomies, 1 multilobectomy, and 1 frontal lobe deafferentiation combined with a temporal lobectomy). There were structural lesions in 85.7% of the specimens. In 16 cases (25.4%) the predominant lesions were malformative (focal glioneuronal hamartias and hamartomas, vascular malformations, abundant ectopic neurons in the white matter, microgyria, and arachnoid cyst). Lesions indicating pre- or perinatal necrosis such as porencephaly, ulegyria, and congenital hemiatrophy were present in 7 cases (11.1%). Twelve specimens (19.0%) contained low-grade neoplasms (7 gangliogliomas, 3 astrocytomas, 1 oligodendroglioma and 1 oligoastrocytoma). There were 3 cases of Rasmussen encephalitis, 1 specimen with atrophy and gliosis due to previous herpetic encephalitis and 1 case with an old abscess wall. Posttraumatic or postoperative changes were the predominant finding in 7 specimens (11.1%). In 7 patients there were only nonspecific changes such as cortical atrophy and gliosis or old hemorrhage. No structural alterations were identified in 9 specimens (14.3%). The findings suggest that the structural lesions observed in the great majority of the specimens were closely related to the pathogenesis of intractable seizures.

Adolescent↗

PubMed1993

Surgical pathology of temporal lobe epilepsy. Experience with 216 cases.

The surgical treatment of chronic epilepsies is increasing rapidly. Here we report the histopathologic findings in 216 consecutive surgical specimens of patients with chronic pharmacoresistant temporal lobe epilepsy. In 75 cases (34.7%) there were tumors, all but two of which were of low histopathological grade (WHO grade I or II). The most common tumors were gangliogliomas (34 cases), pilocytic astrocytomas (17 cases), oligodendrogliomas (9 cases), fibrillary astrocytomas (6 cases), and dysembryoplastic neuroepithelial tumors (6 cases). There were 51 cases with non-neoplastic focal lesions and an additional 13 cases with tumors and non-neoplastic focal lesions within the same specimen. The most frequent non-neoplastic focal lesions were microscopic glioneuronal hamartias (32 cases), glioneuronal hamartomas (7 cases), and vascular malformations (13 cases). The hippocampal formation was structurally well preserved in 71 specimens. In 51 of these (71.8%) there was Ammon's horn sclerosis. Presurgical placement of depth electrodes was invariably associated with circumscribed defects of the brain parenchyma. The implantation of subdural electrodes was sometimes followed by chronic inflammatory changes of the leptomeninges. Our findings indicate that in the majority of patients with medically intractable temporal lobe epilepsy there are significant histopathologic findings, many of which are only rarely encountered otherwise.

Adolescent↗