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Biomedical subjects

M Cervantes

Publications and source records attributed to M Cervantes.

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

[Changes in the cell cycle in breast cancer].

Recent advances in the mechanisms of oncogenesis have revealed a close relationship between the cell cycle and apoptosis. The cell cycle goes through a series of kinases and fosfatases activities that enhance the cyclins. In the mammalian cells, the kinases CDK4/6, CDK2, CDK2 and p34 are linked to the cyclins D, E, A, and B When the cell goes from the phase G1 toward mitosis. When the DNA is altered by intrinsic or extrinsic factors, the control checkpoints should stop the cycle in order to repair the damage. If the DNA cannot be repaired, apoptosis is induced. In cancer, the checkpoints do not function and the unstable genome of the cancer cell is repaired. Some of these changes occur in cancer of the breast and are discussed in this review.

Apoptosis↗
PubMed1996

Effects of diazepam on fentanyl-induced epileptoid EEG activity and increase of multineuronal firing in limbic and mesencephalic brain structures.

Electroencephalographic and clinical signs of epileptoid activity have been associated with the administration of fentanyl during surgery in patients. These phenomena have been in turn related to changes in metabolic rate, oxygen consumption, and blood flow in specific brain structures both in humans and experimental animals. However, direct evidence showing changes in neuronal firing in specific brain regions during fentanyl-induced epileptoid activity has not been reported. Eight adult male cats with chronically implanted bipolar electrodes in the mesencephalic reticular formation, hippocampus, amygdala, and parieto-occipital cortex were included in the study. Different treatments, i.e., vehicle-fentanyl or diazepam-fentanyl, were administered to the experimental animals at 7-day intervals under neuromuscular blockade and assisted ventilation. Electroencephalographic (EEG) seizures, grouped and isolated spikes, and significant increases of multineuronal activity (MUA) were elicited by fentanyl, 50 micrograms/kg iv, in these brain structures. Both EEG and MUA changes reached their maximal values within 6 min of fentanyl administration, and then diminished as time elapsed. Diazepam, 100, 200, or 400 micrograms/kg, but not 50 micrograms/kg iv, significantly reduced or prevented the fentanyl-induced epileptoid EEG activity and MUA increases. The present results show that both fentanyl-induced epileptoid EEG activity as well as the concomitant increase in MUA of brain subcortical structures are part of the same epileptogenic phenomenon, mainly generated at limbic structures. In addition, the effects of diazepam against both epileptoid EEG activity and increase of MUA of brain subcortical structures support the use of benzodiazepines as premedicants for fentanyl anesthesia in order to prevent or to reduce epileptoid phenomena that can result from opioid administration during the anesthetic procedures.

Animals↗
PubMed1995

[Winter epidemic of carbon monoxide poisoning in Badia].

OBJECTIVE: To find the incidence, morbidity and possible causes of the acute carbon monoxide poisonings (ACMP) which occurred in Badia between january 1992 and june 1993. DESIGN: A longitudinal, retrospective study. PATIENTS: Every Badia resident discharged from the Hospital Consortium of Parc Taulí, Sabadell with a diagnosis of ACMP and/or from Barcelona's Red Cross Hospital (RCH) after hyperbaric treatment was considered. MEASUREMENTS AND RESULTS: Cases were identified using the hospital discharge records from Parc Taulí and the RCH. A systematic review of the primary care clinical records was undertaken. The causes of the poisoning were investigated by a technical committee and through the gas company carrying out inspections of dwellings in 1993. The incidence of ACMP was 76.5 per 100,000 inhabitants in 1992 and 109.4 per 100,000 in the first half of 1993. 94% of the 34 cases occurred in December, January, February and March. 50% of those affected were under 17. The number of cases per household varied between 2 and 5 people. The most common underlying cause was the existence of defects in the conduits taking fumes away from gas heaters. The gas review detected defects in installation in 54% of dwellings. CONCLUSIONS: ACMP is a common and serious problem in our environment. The underlying causes and the high number of dwellings at risk have suggested a need for information campaigns in the community.

Adolescent↗
PubMed1995

Effects of propofol on alterations of multineuronal activity of limbic and mesencephalic structures and neurological deficit elicited by acute global cerebral ischemia.

The increment of GABAergic inhibitory activity, the reduction of metabolic rate and oxygen consumption induced by propofol on the neuronal components of brain structures, and its antioxidant potential have supported the possible beneficial effects of this drug against brain damage elicited by cerebral ischemia. Multineuronal activity (MUA) and EEG from mesencephalic reticular formation, hippocampus, and amygdala, and EEG from the parietooccipital cortex were recorded and analyzed during vehicle or propofol, 0.25 mg/kg/min i.v., administered during a 6 h period following a 10 min cardiorespiratory arrest and 2-4 min of reanimation in two groups of cats under neuromuscular blockade and assisted ventilation. This was continued daily during alertness for 8 days after cardiorespiratory arrest along with determining daily neurological deficit scores. Mean MUA frequency, progressively increasing in subcortical structures of untreated cats during the hours following cardiorespiratory arrest, was significantly lower in propofol treated cats. A significant reduction of MUA in the hippocampus was then observed in the untreated but not in the propofol treated cats, and in amygdala in both treated and untreated cats. Alterations of MUA were not observed in the mesencephalic reticular formation during alertness on the days after cardiorespiratory arrest. Significantly lower neurological deficit scores were recorded in propofol treated than in untreated cats the days after cardiorespiratory arrest. It can be concluded that propofol is capable of reducing both brain electrical activity alterations in specific brain structures, and neurological deficit elicited by complete global cerebral ischemia in cats. Inhibition of MUA from limbic and mesencephalic brain structures induced by propofol early after global cerebral ischemia could be related to these effects.

Acute Disease↗
PubMed1994

Cloning of a cDNA encoding ATP sulfurylase from Arabidopsis thaliana by functional expression in Saccharomyces cerevisiae.

ATP sulfurylase, the first enzyme in the sulfate assimilation pathway of plants, catalyzes the formation of adenosine phosphosulfate from ATP and sulfate. Here we report the cloning of a cDNA encoding ATP sulfurylase (APS1) from Arabidopsis thaliana. APS1 was isolated by its ability to alleviate the methionine requirement of an ATP sulfurylase mutant strain of Saccharomyces cerevisiae (yeast). Expression of APS1 correlated with the presence of ATP sulfurylase enzyme activity in cell extracts. APS1 is a 1748-bp cDNA with an open reading frame predicted to encode a 463-amino acid, 51,372-D protein. The predicted amino acid sequence of APS1 is similar to ATP sulfurylase of S. cerevisiae, with which it is 25% identical. Two lines of evidence indicate that APS1 encodes a chloroplast form of ATP sulfurylase. Its predicted amino-terminal sequence resembles a chloroplast transit peptide; and the APS1 polypeptide, synthesized in vitro, is capable of entering isolated intact chloroplasts. Several genomic DNA fragments that hybridize with the APS1 probe were identified. The APS1 cDNA hybridizes to three species of mRNA in leaves (1.85, 1.60, and 1.20 kb) and to a single species of mRNA in roots (1.85 kb).

Amino Acid Sequence↗
PubMed1994

Effects of intrathecal administration of adrenergic agonists on the frequency of copulatory pelvic thrusting of the male rat.

The effects of the intrathecal perispinal administration of adrenergic agonists on the characteristics of frequency, duration, and vigor of pelvic thrusting displayed by male rats during copulation was assessed by an accelerometric technique. A different dose of one drug (noradrenaline, clonidine or isoproterenol) and saline as control was administered at the lumbosacral level of the spinal cord to sexually active male rats in tests of sexual behavior performed at weekly intervals. The intrathecal administration of noradrenaline (alpha-adrenoceptor agonist) increased the frequency of pelvic thrusting in mount and intromission responses, whereas both the alpha 2-adrenoceptor agonist clonidine (25 micrograms) and the beta-adrenoceptor agonist isoproterenol (40 micrograms) reduced the frequency of pelvic thrusting in these responses as compared to values obtained under the intrathecal administration of saline. On the other hand, the duration of the thrusting trains and the potency or vigor of pelvic thrusting in mounts and intromissions did not differ from values obtained under saline treatment. These findings indicate a possible participation of noradrenaline in the modulation of the spinal mechanisms involved in the generation of rhythmic pelvic thrusting performed by the male rat during copulation.

Adrenergic Agonists↗
PubMed1992

EEG signs of "relaxation behavior" during breast-feeding in a nursing woman.

The presence of electroencephalographic signs of "relaxation behavior"; i.e., groups of synchronic, 6-10 Hz, 100-150 microV EEG waves mainly appearing in parieto-occipital regions, have been investigated in a nursing woman during breast-feeding. EEG was recorded once a week from right and left frontal-central, central-parietal, parietal-temporal and parietal-occipital derivations of the mother during breast-feeding of her own child throughout 16 weeks of nursing (from the 4th to the 20th week after delivery). Groups of synchronic 6-10 Hz, 100-150 microV EEG waves were recorded in central-parietal and parietal-temporal derivations, 15-80 sec after starting of suckling of either breast. Proportions of this synchronic EEG activity ranged between 5 to 28% in the central-parietal and 6 to 22% in the parietal-temporal derivations, and significantly higher proportions were found in the right hemisphere. Similarities between EEG signs of "relaxation behavior" elicited by suckling in nursing cats and those elicited by suckling in a nursing woman lead to the possibility that the above described EEG phenomena are an expression of a functional state of the central nervous system which is a part of the integral response involved in the consummatory activity of nursing behavior in women.

Adult↗
PubMed1983

Serotonergic influences on EEG synchronization induced by milk drinking in the cat.

Milk drinking elicits electroencephalographic (EEG) synchronization in the parieto-occipital cortex of cats. This EEG change is a reliable correlate of the consummatory phenomena involved in "relaxation" behavior. The effect of varying serotonin brain levels by administering P-chlorophenylalanine (PCPA) or 5-hydroxytryptophan (5HTP) on this response was studied in 25 young cats. Single or repeated injections (4-8 days) of 50, 100 or 150 mg/kg of PCPA resulted in a dose related decrease in the duration of the EEG parieto-occipital synchronization during fixed periods of milk drinking. A single injection of 3, 10 or 30 mg/kg of 5HTP to chronic PCPA treated cats, restored the EEG parieto-occipital synchronization during milk drinking to control values. Moreover, administration of 5HTP to non-treated cats significantly increased the duration of EEG parieto-occipital synchronization during milk drinking. Our results suggest that brain serotonergic neurons are involved in the development of EEG synchronization during milk drinking.

5-Hydroxytryptophan↗
PubMed1980

Antithrombin III contribution to cholestasis differential diagnosis: its correlation with one stage prothrombin time and factor V.

Levels of antithrombin III (AT III) measured by two different methods, Factor V (FV) and One Stage Prothrombin Time, have been studied in two groups of patients: 55 with chronic liver disease and 22 with extra hepatic cholestasis. Results show a statistically significant correlation between the decrease of AT III and FV in the first group, and the normality of these parameters (unrelated to One Stage Prothrombin Time) in the second group. Levels at AT III and FV correlate directly with the functional integrity of hepatic parenchyma, so they may help in the differential diagnosis of different types of cholestasis.

Antithrombin III↗
PubMed1976

Changes in multiunit activity and EEG induced by the administration of natural progestins to flaxedil immobilized cats.

The effects of progesterone (P) and 7 of its metabolites on the EEG and multiunit activity (MUA) of various limbic structures were studied in flaxedil immobilized cats. Most progestins inhibited the MUA of the mesencephalic reticular formation, hippocampus and hypothalamus and induced cortical EEG synchronization. MUA changes in the mesencephalic reticular formation frequently preceded EEG synchronization. Progestins reduced in the 5 beta postition (pregnanolone, epipregnanolone and pregnanedion) inhibited neuronal discharge and synchronized EEG activity with shorter latencies and in lower doses than those reduced in the 5 alpha position (allopregnanolone and allopregnanedion). Progestins having the delta 4,3-keto structure (P, 20 alpha-hydroxy pregnenone, 20 beta-hydroxy pregnenone) induced electrophysiological changes with prolonged latencies and in doses significantly higher than ring A reduced progestins. Administration of epipregnanolone to "cerveau isole" preparations depressed neuronal firing in those structures located rostral to the level of the brain stem transection (hypothalamus, hippocampus), but failed to increase the already synchronized cortical activity. These results suggest that: a, ring A reduction increases the capacity of P and other delta 4,3-keto progestins to inhibit neuronal discharge in certain brain areas and b, changes in neuronal firing induced by progestins are not necessarily mediated through the cat brain stem reticular formation.

Animals↗