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Biomedical subjects

J M Tusell

Publications and source records attributed to J M Tusell.

At least 19 recordsLinked to original sources
PubMed2000

The orthopaedic status of severe haemophiliacs in Spain.

This paper provides an outline of the results obtained in a cross-sectional study conducted primarily with the aim of ascertaining orthopaedic complications in a group of young severe A and B haemophiliacs, the effects which these complications have on the medical resources used with these patients, and the impact of severe haemophilia on their quality of life. Its secondary aim was to link their current orthopaedic status to the type of treatment they had received prior to the study. Eleven Spanish hospitals took part in this study, monitoring 70 severe haemophiliacs (FVIII:C <2%) without inhibitors who had a mean age of 21.6 years and a median age of 22. Retrospective data collected from birth to the conclusion of the study were used and, for certain variables, data from the last 12 months. The type of treatment given had been on-demand treatment, together with prophylaxis of variable time periods, which in 32 cases (45.7%) were prolonged (>6 months). In 40 cases (57.1%) the patients underwent one or more periods of prophylaxis. Thirty-three patients (47.8%) had over 1000 days of administration of factors VIII and IX. The analysis of the total study group reveal an average of 348 bleeding episodes per patient. The findings of this study revealed that 84.3% of these patients suffer from articular complaints on the Gilbert scale, and 85.7% on the Pettersson scale. In addition, pain was reported in 16.1% of the joints, the most frequently affected being the ankle joints. Twenty-six patients (37%) had undergone orthopaedic surgery from the time of birth to the conclusion of the study. The quality of life of the severe haemophiliacs reviewed seems to have been affected. During the last 12 months, there were 216 outpatient haematological visits and 176 orthopaedic-rehabilitation visits, as well as 12 radiological explorations and two hospitalizations. During these 12 months, medical expenditure totalled $55 473 per patient per year, the most important item being factor concentrates VIII/IX ($54 119 per patient per year). The type of treatment given to these patients (on-demand and/or as secondary prophylaxis) was found to be incapable of preventing haemophilic arthropathy or guaranteeing an acceptable quality of life, although both the administration of coagulant factor concentrate to such patients and the financial resources dedicated to their treatment was very high. Consequently, a strategic change is to be considered for the prevention of haemophilic arthropathy, based on the introduction of replacement treatment involving continuous administration of factors VIII and IX in primary prophylaxis regimens from the first years of life.

Adolescent↗
PubMed1999

Comparative study of the distribution of calmodulin kinase II and calcineurin in the mouse brain.

The Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and the phosphatase calcineurin (CaN) are Ca(2+)/calmodulin-binding proteins that are very abundant in the central nervous system. In the mammalian brain, CaMKII is composed by the association of several similar subunits at different ratios produced by four different genes. CaN is composed of two different subunits produced by two genes. We selected the most abundant subunits of each enzyme in the rodent brain, CaMKII alpha and CaN A, and compared their pattern of expression in the mouse brain by using in situ hybridization histochemistry and immunohistochemistry. We found that CaMKII and CaN were mainly expressed in cerebral cortex, hippocampus, and striatum and that low levels of expression were observed in midbrain and brainstem. CaN was also expressed in cerebellum. In the cell, the kinase and the phosphatase were detected in the perikarya, the neuronal processes, and the nucleus. The present study shows that all the regions of the mouse brain in which CaMKII is expressed also show CaN expression. This fact is consistent with the presence of common substrates for both enzymes or with a regulatory action of one versus the other. The lack of correspondence in the cerebellum could be explained by the fact that the major subunit of the kinase in this brain region is CaMKII beta.

Animals↗
PubMed1999

The Ca2+/calmodulin signaling system in the neural response to excitability. Involvement of neuronal and glial cells.

Ca2+ plays a critical role in the normal function of the central nervous system. However, it can also be involved in the development of different neuropathological and neurotoxicological processes. The processing of a Ca2+ signal requires its union with specific intracellular proteins. Calmodulin is a major Ca(2+)-binding protein in the brain, where it modulates numerous Ca(2+)-dependent enzymes and participates in relevant cellular functions. Among the different calmodulin-binding proteins, the Ca2+/calmodulin-dependent protein kinase II and the phosphatase calcineurin are especially important in the brain because of their abundance and their participation in numerous neuronal functions. We present an overview on different works aimed at the study of the Ca2+/calmodulin signalling system in the neural response to convulsant agents. Ca2+ and calmodulin antagonists inhibit the seizures induced by different convulsant agents, showing that the Ca2+/calmodulin signalling system plays a role in the development of the seizures induced by these agents. Processes occurring in association with seizures, such as activation of c-fos, are not always sensitive to calmodulin, but depend on the convulsant agent considered. We characterized the pattern of expression of the three calmodulin genes in the brain of control mice and detected alterations in specific areas after inducing seizures. The results obtained are in favour of a differential regulation of these genes. We also observed alterations in the expression of the Ca2+/calmodulin-dependent protein kinase II and calcineurin after inducing seizures. In addition, we found that reactive microglial cells increase the expression of calmodulin and Ca2+/calmodulin-dependent protein kinase II in the brain after seizures.

Animals↗
PubMed1998

Decreased expression of calmodulin kinase II and calcineurin messenger RNAs in the mouse hippocampus after kainic acid-induced seizures.

The Ca2+/calmodulin-dependent protein kinase II (CaMKII) and the phosphatase calcineurin (CaN) are especially abundant in the mammalian CNS, where they have been implicated repeatedly in different neuronal functions. CaMKII is a holoenzyme that is likely to be constituted of both homomultimers and heteromultimers, CaMKIIalpha and CaMKIIbeta being the most abundant subunits in the brain. CaN is a heterodimer constituted of a catalytic subunit (CaN A) and a regulatory subunit (CaN B), and CaN Aalpha is the predominant form in the brain. We studied the expression of CaMKIIalpha, CaMKIIbeta, and CaN Aalpha subunit messenger RNAs in the mouse hippocampus at different times after the administration of a convulsant dose of kainic acid. CaMKIIalpha and CaN A immunohistochemistry was also performed. We observed a transient decrease in the three messenger RNAs in the kainic acid-treated mice, peaking at 5 or 24 h of treatment. The effect had disappeared completely 8 days after treatment. No significant alterations in CaMKII or CaN immunolabelling were observed in the hippocampus of kainic acid-treated mice. The observed modifications could be due to the neuronal hyperexcitability induced by kainic acid rather than neuronal degeneration, because no areas of neuronal loss were detected. Our results suggest that the expression of CaMKII and CaN mRNAs is down-regulated in neuronal cells in response to the hyperexcitability induced by kainic acid. The transient nature of the effect and the apparent absence of significant modifications in the amount of their corresponding proteins may be related to the absence of neuronal damage.

Animals↗
PubMed1997

Differential response of calmodulin genes in the mouse brain after systemic kainate administration.

In the central nervous system, many of the effects resulting from an increase in the intracellular levels of calcium are mediated by calmodulin, a major calcium-binding protein in the mammalian brain. Calmodulin is expressed by three different genes, namely CaM I, CaM II and CaM III, all of which encode an identical protein. We studied the expression of calmodulin in the mouse brain at different times after the administration of a convulsant dose of kainate, a potent neuroexcitotoxic agent. We detected the presence of the different calmodulin messenger RNAs and of the protein itself in brain sections by in situ hybridization histochemistry and immunocytochemistry respectively. In addition, we determined the calmodulin content in brain regions by radioimmunoassay. Kainate-treated animals did not show areas of neuronal death at the different times following administration considered. An increase in the hybridization signal for CaM I messenger RNAs was observed from 5 h after kainate administration in the different brain regions tested. In contrast, the CaM II messenger RNA signal decreased gradually to a minimum 24 h after treatment in the hippocampus, while the CaM III messenger RNA signal was mostly unaffected. Calmodulin immunoreactivity also increased in the hippocampus. Nevertheless, we did not detect any significant difference in calmodulin content between brain regions of control and treated animals by radioimmunoassay. Kainate treatment induced modifications in the expression of calmodulin at the level of both messenger RNAs and protein. The results suggest a differential regulation of the three calmodulin genes in the adult mouse brain and a post-transcriptional or a post-translational regulation of calmodulin expression.

Animals↗
PubMed1997

Calmodulin is expressed by reactive microglia in the hippocampus of kainic acid-treated mice.

Calmodulin is a calcium-binding protein that is highly abundant in the brain, where it is involved in many essential functions. The protein is mainly expressed by neuronal cells. Calmodulin is encoded by three different genes in mammals, all of them producing an identical protein. Alterations in the expression of either calmodulin genes or protein have been reported in the rodent brain by several authors in different experimental situations. However, no mention has been made to date of possible alterations in calmodulin expression in glial cells in response to certain stimuli. In the present study, we found an increase in the expression of calmodulin in reactive microglial cells in the mouse hippocampus 24 h after an intraperitoneal administration of a convulsant dose of kainic acid. The results show that a high expression of calmodulin can be added to the list of changes described to occur in microglial cells when they become reactive microglia in response to certain kinds of stimuli, in contrast to the non-detectable level of expression of this protein observed in the resting microglial cells. It is difficult to explain such an increase due to the great number of processes in which calmodulin is involved, but the great level of calmodulin observed in the reactive microglial cells shows that calmodulin immunolabelling can be used to reveal these kinds of cells.

Animals↗
PubMed1996

Reserpine potentiates NMDA-induced c-fos mRNA expression in the mouse brain.

The systemic administration of a non-convulsant dose of N-methyl-D-aspartate (NMDA; 75 mg/kg i.p.), which was associated with motor activation, induced a regional c-fos mRNA expression in the mouse brain. The NMDA-induced c-fos mRNA expression was predominant in the dentate gyrus and in the medial mammillary nucleus and less pronounced in other hippocampal areas, cortical areas, bed nucleus of the stria terminalis and posterior amygdaloid nuclei. It is suggested that the hippocampus and/or the extended amygdala might be involved in the previously hypothesized dopamine-independent NMDA-mediated motor activation mechanism. No increase in c-fos mRNA expression was observed 21 h after reserpine treatment (5 mg/kg s.c.). However, reserpinization induced a significant potentiation of the NMDA-induced c-fos mRNA expression. These results show the existence of a strong and selective amine-dependent modulation of NMDA neurotransmission in the brain.

Animals↗
PubMed1996

Comparative study of the pattern of expression of calmodulin messenger RNAs in the mouse brain.

Calmodulin is a major calcium-binding protein in the mammalian brain, playing an important role in neuronal cell function. Its amino acid sequence is highly conserved and the protein is encoded by multiple genes. In the mouse brain, as well as in the rat and the human brain, three different genes have been detected for calmodulin, CaM I, CaM II and CaM III, all of which encode an identical protein. We studied the pattern of expression of the three calmodulin genes and the pattern of calmodulin distribution in the mouse brain by in situ hybridization histochemistry and immunohistochemistry. We found that calmodulin messenger RNAs from the three calmodulin genes were widely expressed in the mouse brain. Nevertheless, there were differences in their patterns of distribution. In general, all calmodulin messenger RNAs were preferentially distributed in hippocampus, cerebral cortex and cerebellar cortex, and CaM II messenger RNA also in caudate-putamen. However, all messenger RNAs showed clearly differentiated patterns of distribution in the hippocampus and the cerebellar cortex. Calmodulin immunoreactivity was present in all cells so far examined. Immunostaining was observed both in the cell nucleus, where it was especially strong, and in the cytoplasm. Our results suggest that the three calmodulin genes are differentially regulated in the mouse brain and also that, although all calmodulin genes have a basal expression, precise regulation of calmodulin levels might be attained through the different contribution of the three calmodulin genes.

Animals↗
PubMed1995

An association between clotting factor concentrates use and mortality in human immunodeficiency virus-infected hemophilic patients.

There is much evidence that clotting factor concentrates (CFC), especially the so-called intermediate-purity preparations, exert an immunomodulating effect in vitro. The impact of this effect on the outcome of human immunodeficiency virus (HIV) infection in hemophiliacs is still controversial. In this retrospective cohort study, the effects of treatment with CFC on mortality and progression to acquired immunodeficiency syndrome (AIDS) were estimated while controlling for individual risk factors. Logistic regression and survival analysis, including the Cox proportional-hazards regression model, were performed with data from a 11-year follow-up of 225 hemophilic patients seropositive for HIV type 1 (HIV-1) of two hemophilia centers. Mortality and progression to AIDS rates were strongly associated with lower administration of CFC. After adjusting for age, a statistically significant and robust association was observed. The use of CFC was negatively associated with progression to AIDS (P = .0252) and mortality (P = .0033). The adjusted relative hazards of mortality and progression to AIDS rate between the most treated patients (> 700 IU/kg/yr) versus the least treated (< or = 700 IU/kg/yr) were 0.53 (confidence limits, 0.33 to 0.86) and 0.57 (0.39 to 0.84), respectively. Although the effects of other unmeasured risk factors cannot be excluded with certainty, these results suggest that there is a negative association between treatment with CFC and progression to AIDS and mortality.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Effect of hexachlorocyclohexane isomers on calmodulin mRNA expression in the central nervous system.

Three different calmodulin genes that encode the same protein have been found in the brain of all mammalian species so far examined. Little is known about the factors involved in regulating the expression of this gene family in the central nervous system. We have investigated the possibility of differential expression of two calmodulin genes, CaM I and CaM II, which are expressed strongly in neuronal cells in the adult rat brain, after treatment with the gamma (lindane) and the delta isomers of the hexachlorocyclohexane (HCH). In this study a decrease of CaM I mRNA (mainly in the 4.0 kb transcript) was found in the cortex of the rats after 24 h of isomer administration. CaM I expression seemed to be more sensitive to delta isomer action, whereas the gamma isomer acted mainly at CaM II level. The levels of mRNA of calmodulin CaM II gene were also found to decrease after lindane administration; delta-HCH produced an increase of this transcript. These results were obtained by Northern blot analysis and confirmed by means of in situ hybridization. Our results suggest that levels of neuronal calmodulin mRNA species are modified in response to changes in neuronal activity.

Animals↗
PubMed1995

Regulation of c-fos expression by convulsants and hexachlorocyclohexane isomers in primary cultures of cortical neurons.

Primary cortical cultures were used to study the effects of four convulsants on c-fos expression. Approximately 30% of the neurons in these cultures displayed c-fos nuclear immunostaining under basal conditions. The addition of tetrodotoxin, nifedipine, or delta-hexachlorocyclohexane produced a significant decrease in c-fos basal values. Lindane (gamma-hexachlorocyclohexane), Bay K 8644, pentylenetetrazole, and picrotoxinin produced a significant increase in c-fos immunoreactivity and in c-fos mRNA expression. Treatment of cells with tetrodotoxin before administration of the convulsant agents lowered c-fos staining below basal levels. In contrast, delta-hexachlorocyclohexane or nifedipine failed to block only the picrotoxin-induced increase. The differential pattern of expression shown by c-fos after these treatments suggests various mechanisms of action for the compounds studied. The results obtained with delta-hexachlorocyclohexane and nifedipine suggest that picrotoxinin activates c-fos expression by calcium-requiring intracellular signaling pathways that are different from those activated by Bay K 8644, pentylenetetrazole, or gamma-hexachlorocyclohexane, which, at least in part, act via L-type calcium channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1995

Convulsant agents activate c-fos induction in both a calmodulin-dependent and calmodulin-independent manner.

Calcium acts as a second messenger and can enter neurons through several types of calcium channel. We sought to determine whether the calcium-dependent mechanisms inducing c-fos expression are identical following activation, by appropriate drugs, of L-type voltage-sensitive calcium channels or NMDA and non-NMDA receptors or following inhibition of the GABAergic system. We used primary cortical neurons and OF1 mice, and the levels of c-fos protein and c-fos mRNA were detected after treatment with the drugs by means of immunocytochemistry and in situ hybridization. The calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) abolished gamma-hexachlorocyclohexane-, Bay K 8644-, pentylenetetrazole-, and kainic acid-induced increases in c-fos expression in cultured neurons. Conversely, W-7 did not affect either NMDA- or picrotoxinin-mediated increases in c-fos expression. In mice, the pattern of protooncogene expression displayed some differences compared with cultured neurons, depending on the treatment. W-7 administered before gamma-hexachlorocyclohexane, Bay K 8644, or pentylenetetrazole blocked the expression of c-fos elicited by these compounds. However, W-7 was not able to abolish c-fos expression induced by picrotoxinin. In the animals treated with W-7 before kainic acid or NMDA administration, c-fos expression was inhibited in cerebral cortex, but it was still present in hippocampus. These results agree with the existence of diverse mechanisms transducing the calcium signals to the nucleus. Calmodulin may mediate neuronal responses depending on the route by which calcium enters the neuron, resulting in activation of different enzymes.

Animals↗
PubMed1994

Anticonvulsant activity of calmodulin antagonist W-7 in convulsions induced by lindane and BayK-8644: effects in c-fos expression.

The anticonvulsant activity of calmodulin antagonist W-7, was investigated on convulsions induced in mice by the insecticide lindane and by the calcium channel agonist BayK-8644. We also studied the inhibitory effect of W-7 on on c-fos mRNA expression induced by both convulsants. We observed a good correlation between doses and the acute convulsive effects of lindane and BayK-8644. The incidence rate and time to onset were clearly dose-dependent. W-7 antagonized the convulsive effects of lindane and BayK-8644 in all the parameters studied. A significant decrease in the incidence rate and time to onset were observed when they are compared with the values obtained with the ED100 of lindane- and BayK-8644 induced seizures. Both were able to activate the mRNA expression of the proto-oncogene. The pattern of this expression displayed by in situ hybridization was very similar. A dramatic increase was found in dentate gyrus and high levels of mRNA expression also occurring in hippocampal fields and cortical regions. In accordance with the behavioural results, W-7 antagonized also the c-fos expression induced by lindane and BayK-8644. Our results suggest that lindane as BayK-8644 may activate voltage-dependent calcium channels leading to calmodulin activation.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Anticonvulsant activity of delta-HCH, calcium channel blockers and calmodulin antagonists in seizures induced by lindane and other convulsant drugs.

The anticonvulsant activity of delta-HCH and of a calmodulin antagonist, W-7 were investigated on convulsions induced in mice by lindane (ED100 100 mg/kg), by GABAergic antagonists PTZ (ED100 60 mg/kg) and PTX(ED100 4 mg/kg), by calcium channel agonist BAY-K-8644 (ED100 5 mg/kg), by two agonists of excitatory amino acid receptors, kainic acid (ED100 80 mg/kg) and NMDA (ED100 160 mg/kg and by the atypical benzodiazepine Ro 5-4864 (ED100 40 mg/kg). The anticonvulsant activity of a voltage-dependent calcium channel antagonist, nifedipine was also investigated on convulsions induced by Ro 5-4864, BAY-K-8644, kainic acid and NMDA. delta-HCH antagonized lindane- and BAY-K-8644-induced convulsions (ED50 231 (172-309) mg/kg and 148 (142-154) mg/kg, respectively) and at concentrations up to 300 mg/kg failed to antagonize Ro 5-4864, kainic acid and NMDA convulsions. In contrast delta-HCH potentiated PTX-induced seizures. Nifedipine antagonized BAY-K-8644- and kainic acid-induced convulsions (ED50 6.5 (4.3-9.7) mg/kg and 30 (13-70) mg/kg but at concentrations up to 20 mg/kg failed to antagonize Ro 5-4864 and 25% of protection was observed on NMDA-induced convulsions at the highest dose (20 mg/kg). The ED50 of W-7 to antagonize convulsions induced by lindane and BAY-K-8644 were 12 (8-19) mg/kg and 49 (29-85) mg/kg, respectively. Some anticonvulsant effect was observed against PTZ and NMDA but without any dose-dependent anticonvulsant activity. W-7 did not protect against PTX and kainic acid convulsions and 30% of protection was observed against convulsions at the highest dose of W-7 (75 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗