Survival of the nematophagous fungus Duddingtonia flagrans to in vitro segments of sheep gastrointestinal tract.

The nematophagous fungus Duddingtonia flagrans is used in integrated management of gastrointestinal nematodes in ruminants. The chlamydospores of the fungus, orally administered, pass through the segments of the ruminant digestive tract and, in the feces, capture the nematodes preventing their migration to grasslands. The drastic conditions of the gastrointestinal segments can negatively affect the fungus' biocontrol activity. The aim of this study was to assess the effect of in vitro conditions of the sheep's main gastrointestinal segments on the concentration, viability and nematode predatory ability of D. flagrans chlamydospores. The segments evaluated separately in vitro were the oral cavity, rumen, abomasum, and small intestine. The results showed that chlamydospores concentration was not affected by exposure to the different segments. The viability of the chlamydospores after exposure to the oral cavity (2.53 × 106 CFU/mL) and small intestine (1.24 × 105 CFU/mL) was significantly lower than its control treatment, with values of 6.67 × 106 CFU/mL and 2.31 × 105 CFU/mL respectively. Nematode predatory ability after rumen exposure was reduced by 7% compared to the control treatment, by 25% after abomasum exposure and by 17% after small intestine. This study revealed the individual in vitro effect of each segment of ovine gastrointestinal tract on the integrity of this strain of the fungus D. flagrans affecting its viability and nematode predatory ability under the evaluated conditions. Delivery systems could be designed to protect chlamydospores considering the impact of each gastrointestinal segment.

[Does Alzheimer's disease exist in all primates? Alzheimer pathology in non-human primates and its pathophysiological implications (II)]. / ¿Existe la enfermedad de Alzheimer en todos los primates? Patología Alzheimer en primates no humanos y sus implicaciones fisiopatológicas (II).

INTRODUCTION: In the ageing process there are some species of non-human primates which can show some of the defining characteristics of the Alzheimer's disease (AD) of man, both in neuropathological changes and cognitive-behavioural symptoms. The study of these species is of prime importance to understand AD and develop therapies to combat this neurodegenerative disease. DEVELOPMENT: In this second part of the study, these AD features are discussed in the most important non-experimental AD models (Mouse Lemur -Microcebus murinus, Caribbean vervet -Chlorocebus aethiops, and the Rhesus and stump-tailed macaque -Macaca mulatta and M. arctoides) and experimental models (lesional, neurotoxic, pharmacological, immunological, etc.) non-human primates. In all these models cerebral amyloid neuropathology can occur in senility, although with different levels of incidence (100% in vervets;<30% in macaques). The differences between normal and pathological (Alzheimer's) senility in these species are difficult to establish due to the lack of cognitive-behavioural studies in the many groups analysed, as well as the controversy in the results of these studies when they were carried out. However, in some macaques, a correlation between a high degree of functional brain impairment and a large number of neuropathological changes ("possible AD") has been found. CONCLUSIONS: In some non-human primates, such as the macaque, the existence of a possible continuum between "normal" ageing process, "normal" ageing with no deep neuropathological and cognitive-behavioural changes, and "pathological ageing" (or "Alzheimer type ageing"), may be considered. In other cases, such as the Caribbean vervet, neuropathological changes are constant and quite marked, but its impact on cognition and behaviour does not seem to be very important. This does assume the possible existence in the human senile physiological regression of a stable phase without dementia even if neuropathological changes appeared.

[Does Alzheimer's disease exist in all primates? Alzheimer pathology in non-human primates and its pathophysiological implications (I)]. / ¿Existe la enfermedad de Alzheimer en todos los primates? Afección de Alzheimer en primates no humanos y sus implicaciones fisiopatológicas (I).

INTRODUCTION: Many publications consider that Alzheimer's disease (AD) is exclusive to the human species, and that no other animal species suffers from the disease. However, various studies have shown that some species can present with some of the defining characteristics of the human disease, including both neuropathological changes and cognitive-behavioural symptoms. DEVELOPMENT: In this work, the results published (PubMed) on senile brain changes in non-human primates of different degrees of evolution, are reviewed. The neuropathological changes associated with the accumulation of amyloid or highly phosphorylated tau protein are rare outside the primate order, but in all the sub-orders, families, genera and species of non-human primates that have been studied, some senile individuals have shown amyloid accumulation in the brain. In fact, in some species the presence of these deposits in senility is constant. Changes related to the accumulation of tau protein are always of very little significance, and have been detected only in some non-human primate species, both little evolved and highly evolved. In different species of non-human primates, some types of cognitive-behavioural changes are more common in some senile individuals when compared with both normal adult individuals and other senile individuals of the species. The importance of determining the longevity of the species in different habitats (natural habitats, new habitats, semi-captivity, captivity) is stressed in these studies. CONCLUSIONS: Morphological, histochemical and cognitive-behavioural features similar to those observed in elderly humans are present in senile non-human primates. Moreover, other characteristics seen in non-human primates could be indicative of a pathological «Alzheimer type¼ ageing.

Concordance between the Piko - 1 portable device and pneumotachography in measuring PEF and FEV(1) in asthmatic children.

OBJECTIVE: To assess concordance in the measurement of peak expiratory flow (PEF) and forced expiratory volume ino ne second (FEV(1)) between the portable device Piko-1 (Ferraris) and a pneumotachograph. PATIENTS AND METHODS: Forced spirometry (Master Screen Jaeger) was performed according to ATS/ERS norms, selecting the best value of three curves, and three measurements with the Piko-1 were recorded the recommendations of the manufacturer. RESULTS: Eighty patients between 5-18 years of age were studied. Based on the Bland-Altman method, the mean differences obtained were 9.82 (95%Cl: 2.43-17.21) for PEF and 0.17 (95%CL: 0.12-0.21 for FEV(1). The intraclass correlation coefficient was 0.96 (p <0,001; 95%Cl: 0.93-0.97) for PEV(1) and 0.93 (p<0,0001; 95%Cl: 0.89-0.95) for PEF. CONCLUSIONS: Piko-1 offers FEV(1) measurements close to those obtained with forced spirometry, thus allowing more exact patient assessment in home-based follow-up emergency services, or hospital wards.

Genes involved in mitochondrial biogenesis/function are induced in response to bilio-pancreatic diversion in morbidly obese individuals with normal glucose tolerance but not in type 2 diabetic patients.

AIMS/HYPOTHESIS: The mechanisms allowing normalisation of insulin sensitivity and reversal of type 2 diabetes after bilio-pancreatic diversion (BPD) have not been elucidated. We studied whether the expression of genes relevant to mitochondrial biogenesis/function is induced in response to BPD and whether the response differs between morbidly obese patients with normal glucose tolerance (NGT) and patients with type 2 diabetes. METHODS: The effect of stable weight reduction after BPD on metabolic variables and expression of nuclear genes encoding for mitochondrial proteins or regulators of mitochondrial function was investigated in skeletal muscle. Insulin sensitivity was assessed by euglycaemic-hyperinsulinaemic clamp and substrate oxidation by indirect calorimetry. RESULTS: Both NGT and type 2 diabetic patients showed a net improvement of insulin sensitivity, with the latter also showing blood glucose normalisation. NGT patients had a large increase in glucose oxidation and substantial reduction in lipid oxidation. In contrast, type 2 diabetic patients had a blunted response to BPD in terms of glucose oxidation. NGT patients showed increased expression of genes encoding mitofusin 2, porin or citrate synthase; no significant changes were detected in diabetic patients. The expression of genes regulating mitochondrial activity (PGC-1beta [also known as PPARGC1B], PGC-1alpha [also known as PPARGC1A], PPARdelta [also known as PPARD], SIRT1) was induced only in NGT patients. CONCLUSIONS/INTERPRETATION: These findings indicate that weight loss after BPD exerts a beneficial effect on insulin sensitivity via mechanisms that are independent of the expression of genes involved in mitochondrial biogenesis/activity. Furthermore, the observation that gene expression is not altered with weight loss in type 2 diabetic patients while it is induced in NGT patients suggests a heritable component.

[Bronchodilator test: is 9% of the predicted value the same as 12% of the initial value]. / Prueba de broncodilatación: ¿9% sobre el valor teórico o 12% sobre el valor basal es lo mismo?

INTRODUCTION: The bronchodilator test (BDT) is an important tool used in pulmonary function. Changes in forced expiratory volume in one second (FEV1) can be expressed as absolute change, or per cent of initial or predicted value. When the initial value is used, there may be a bias, as the smaller this value is, the greater the response will be. The main objective of this study is to establish whether there is any difference in using per cent of the initial spirometry value or per cent of the predicted value in order to consider a bronchodilator test positive, and if the initial obstruction of the patient influences such differences. MATERIAL AND METHODS: A retrospective analysis of the BDT made between October 1997 and February 2008. The results using an increase of 9% from the predicted FEV1 were compared with using 12% from the initial FEV1. The patients were divided into three groups depending on initial obstruction: no obstruction (FEV1>80% of predicted), mild (FEV1=60-80% of predicted) and moderate-severe (FEV1<60% of predicted). The kappa index of agreement between both methods was calculated. RESULTS: A total of 4352 BDT were analysed. The agreement between both methods was high (k=0.832). In the group without initial obstruction (N=3007) the kappa index was 0.781, in the mild obstruction group (N=1067) the kappa index was 0.966 and in the moderate-severe group (N=278) it was 0.788. CONCLUSION: This study demonstrates that, although there is a good agreement between both methods, in patients with initial moderate-severe obstruction and in patients without initial obstruction this agreement tends to be lower.

Immunohistochemical increase in cyclooxygenase-2 without apoptosis in different brain areas of subchronic nicotine- and D-amphetamine-treated rats.

Cyclooxygenase-2 (COX-2) upregulation has been related to both neurodegeneration and physiological processes. To clarify whether nicotine-induced upregulation of COX-2 occurs, and to analyse its significance, a comparative immunohistochemical and Western blot study was performed on the frontoparietal cortex, hippocampus and cerebellar cortex of rats treated (14 days) with nicotine, D(+)amphetamine (0.35 and 1.16 mg free base/kg/day, respectively), or both drugs simultaneously. None of these treatments promoted neuronal apoptosis. Lipid peroxidation increased in the hippocampus of the nicotine-treated rats and in all the brain regions examined in the D(+)amphetamine rats, but not in the double-treated animals. Both molecules increased the COX-2 content (as determined by the number of immunopositive neurons and the intensity of their immunodeposits) in an area-, layer- and neuron type-dependent manner, in all brain regions in which a large number of COX-2 immunopositive neurons were observed in controls (the somatosensory cortical areas, CA-1, CA-3, the gyrus dentatus, the ectorhinal/perirhinal areas, and the gyrus cingularis). No increase was seen in the motor cortical areas, while a reduction was recorded in the cerebellar cortex; these regions had only a few immunopositive neurons in controls. Western blot analysis revealed a 50-80% increase in COX-2 in the brain cortex and hippocampus of nicotine-treated rats, and similar increases (150-200%) in the cortex of the D(+)amphetamine- and nicotine + D(+)amphetamine-treated rats. Nicotine-induced upregulation of COX-2 seems to be related to neuronal plasticity rather than neurodegeneration. Nicotine agonists might be useful in the treatment of cognitive disorders.

[Lung function changes after haematopoietic stem cell transplantation]. / Alteraciones de la función pulmonar tras el trasplante de progenitores hematopoyéticos.

OBJECTIVE: To evaluate lung function abnormalities in children who underwent haematopoietic stem cell transplantation (HSCT) and to compare these abnormalities between autologous and allogenic transplantation. PATIENTS AND METHODS: Prospective observational study from 1996 to 2005. Ninety-three children receiving HSCT, 47 autologous and 46 allogenic, were included. Lung function tests were performed before transplantation and at 2, 6, 12 and 24 months afterwards. The following indices were determined: forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity (FVC), total lung capacity (TLC), and carbon monoxide diffusing capacity (DLCO). Paired Student's t-test was used for statistical analysis of data. RESULTS: Before HSCT, 6.8% of the children had FEV1<80%, 1% FEV1/FVC<80%, 7.8% TLC<80% and 13.5% DLCO<70%. At 2 months, FEV1/FVC, TLC and DLCO were significantly reduced, when compared to pre-transplantation values (p=0.05, 0.011 and p<0.001, respectively). Lung function gradually improved from 6 months post-transplantation, but did not reach pre-transplantation values at 24 months. No significant differences were found when comparing allogenic and autologous transplantation, apart from a lower FEV1/FVC value at 6 months (p=0.02) in the first group. CONCLUSIONS: An important proportion of children who undergo HSCT have early pulmonary abnormalities (at 2 and 6 months after transplantation) with partial recovery at 24 months.

Lesions and dysfunctions of the nucleus basalis as Alzheimer's disease models: general and critical overview and analysis of the long-term changes in several excitotoxic models.

The cholinergic hypothesis of Alzheimer's Disease (AD) has led to a number of animal models to study in vivo the pathogeny of cortical cholinergic involution. The lesion of the cholinergic neurons of the basal forebrain, especially of the nucleus basalis magnocellularis (nbm) of rodents, has been the most utilized method for obtaining these models. Toxic substances such as quinolic, kainic, NMDA, ibotenic and quisqualic acids, the specific cholinergic toxin AF64, amyloid, and antibodies to neurotrophic factors; etc, have been used to produce such lesions. These investigations have helped our understanding of the role of cerebral cholinergic innervation in cognitive disorders and their treatments. However, this research has provided conflicting results, and much controversy has developed surrounding the role of the cholinergic systems and the suitability of these models. It is very important to take into account the exact type of nbm/cortical lesion produced, and its evolution, if meaningful results are to be obtained. This review covers the theoretical and practical use of nbm lesion models, and examines the main positive and negative results obtained by different authors in the light of our own observations on the long-term (3 years) morphological and biochemical changes that occur in several kinds of nbm-lesion model rats. The changes seen were very different, but many of them were increased up to the end of life with no clear relationship with the development of the original lesion.

[Ring chromosome 20, hypersensitivity to valproate and hyperammonemic encephalopathy]. / Cromosoma 20 en anillo, hipersensibilidad al valproato y encefalopatía hiperamoniémica.

INTRODUCTION: Ring chromosome 20 syndrome (C20A) is characterised by mental retardation, behavioural disorders, dysmorphias and refractory epilepsy with polymorphic seizures. It should therefore be treated with broad-spectrum antiepileptic drugs (AEDs), such as valproate (VPA) and topiramate (TPM). The relatively frequent hypersensitivity reactions to aromatic AEDs, not to VPA, the hyperammonemic encephalopathy (HAE) caused by the combination of VPA and TPM and the chromosome disorder described, affecting the same patient, do not appear in the literature we reviewed. CASE REPORT: A patient aged 5 years who, at the age of 11 months, was seen to have psychomotor retardation, microcephaly, plagiocephaly, facial dysmorphia and hypotonia. At 26 months, the patient presented seizures with fever, sucking, perioral cyanosis, clonisms in the upper extremities and hypotonia. Karyotype: C20A, with no mosaicism. Treatment was started with VPA up to 600 mg/day, and moderate eosinophilia appeared from 450 mg/day onwards. At the age of 4 years, the patient suffered partial complex seizures, which stopped with the addition of TPM. At the same age there was also anorexia, loss of weight, adynamia, hypotonia, drowsiness, confusion, increased eosinophilia (20.3%) and IgE and a rash caused by the VPA. The clinical features yielded on adding dexchlorpheniramine. Nine months later, apathy, adynamia, eosinophilia and hyperammonemia reappeared; we therefore reduced and later stopped administration of VPA, although TPM was maintained. CONCLUSIONS: No relation between hypersensitivity to VPA, HAE and C20A has been described. The VPA TPM combination was effective, but in the end we had to stop administering VPA because of hypersensitivity and the side effects (HAE) of the combination.

Chronic nicotine administration increases NGF-like immunoreactivity in frontoparietal cerebral cortex.

Nicotine/nicotine agonists, which have been proposed as therapeutic agents for the treatment of Alzheimer's disease and other neurodegenerative disorders, produce a wide variety of effects on the nervous system. Some mechanisms involved remain poorly understood. In this work, immunohistochemical techniques were used to determine the effect of nicotine on nerve growth factor (NGF) in the frontoparietal (motor, somatosensory) brain cortex of the albino rat. Nicotine was chronically administered intraperitoneally using osmotic pumps (0.35 mg nicotine base/kg body weight/day for 14 days). An increase in the number and the immunoreaction intensity of NGF-like positive pyramidal and nonpyramidal neurons of these cortical areas was observed after treatment. Immunopositive astroglial cells were always seen in sections of treated animals but not in controls. The neuropil of control animals was, in general, devoid of reaction, but in treated animals, immunopositive prolongations were located randomly, some in close association with capillaries. At the electron microscopic level, these prolongations were demonstrated as belonging to neurons (dendrites and axons) and astroglial cells. Nicotinic activation of selected neurons and glial cells seems to trigger NGF/neurotrophic mechanisms, suggesting their use may be of benefit in prevention and treatment of neurodegenerative diseases.

Corticosteroids for Bell's palsy (idiopathic facial paralysis).

BACKGROUND: Inflammation and oedema of the facial nerve are implicated in causing Bell's palsy. Corticosteroids have a potent anti-inflammatory action which should minimise nerve damage and thereby improve the outcome of patients suffering from this condition. OBJECTIVES: The objective of this review was to assess the effect of steroid therapy in the recovery of patients with Bell's palsy. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group register for randomised trials, as well as MEDLINE, EMBASE and LILACS (to December 2000). We contacted known experts in the field to identify additional published or unpublished trials. SELECTION CRITERIA: Randomised trials comparing different routes of administration and dosage schemes of corticosteroid or adrenocorticotrophic hormone therapy versus a control group where no therapy considered effective for this condition was administered, unless it was also given in a similar way to the experimental group. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed eligibility, trial quality, and extracted the data. MAIN RESULTS: Three trials with a total of 117 patients were included. One trial compared cortisone acetate with placebo; one compared prednisone plus vitamins, with vitamins alone; and one, not-placebo controlled, tested the efficacy of methylprednisolone. Allocation concealment was appropriate in two trials, and the data reported allowed an intention-to-treat analysis. Overall 13/59 (22%) of the patients allocated to steroid therapy had incomplete recovery of facial motor function six months after randomisation, compared with 15/58 (26%) in the control group. This reduction was not significant (relative risk 0.86, 95% confidence interval 0.47 to 1.59). The reduction in the proportion of patients with cosmetically disabling sequelae six months after randomisation was also not significant (relative risk 0.86, 95% confidence interval 0.38 to 1.98). REVIEWER'S CONCLUSIONS: The available evidence from randomised controlled trials does not show significant benefit from treating Bell's palsy with corticosteroids. More randomised controlled trials with a greater number of patients are needed to determine reliably whether there is real benefit (or harm) from the use of steroid therapy in patients with Bell's palsy.

Histochemical study of acute and chronic intraperitoneal nicotine effects on several glycolytic and Krebs cycle dehydrogenase activities in the frontoparietal cortex and subcortical nuclei of the rat brain.

The effects of nicotine on the activity of different dehydrogenases in frontoparietal regions and subcortical nuclei of the rat brain have been studied using histochemical methods. Nicotine sulphate was intraperitoneally administered in acute (4 mg/kg/day x 3 days) or chronic (ALZET osmotic pump providing 2 mg/kg/day x 15 days) doses. The enzymes analyzed were glyceraldehyde-3-phosphate, lactate, malate and succinate dehydrogenases (gly3PDH, LDH, MDH, and SDH, respectively). The results demonstrate that chronic as well as acute administration of nicotine produced strong increases in all these enzymatic activities in the superior layers (I, II and III) of the frontoparietal cortex (cingulate, motor and somatosensory regions); but high increases were not seen in the deeper layers of the cortex or in the subcortical nuclei (substantia nigra, caudate-putamen, nucleus accumbens or nucleus basalis magnocellularis). These hyperactivities were produced in brain regions with normally low enzymatic activity (cortex), but not in those with great intensity (subcortical nuclei). The results are in rough agreement with previous reports on nicotine-induced increases in glucose utilization, gly3PDH genic expression and neuronal hyperactivity in the brain cortex; but significant discrepancies between the cortical enzymatic maps and those obtained both in these studies and others on nicotine(N)-receptor localization have been appreciated. The results support the hypothesis that nicotinic cholinergic drugs can have metabolic, long-lasting stimulant effects on cortical neurons at specific points (probably layer III pyramidal cells and structures with alpha7-N-receptors) of the cortical circuits that could be of great interest in improving altered cognitive functions that are present in Alzheimer disease, as well as in other less severe mental disturbances. Mitochondrial hyperfunction should also be evaluated as a possible side-effect (as an oxidative stress inductor) of these kinds of drugs.

Levels, phosphorylation status and cellular localization of translational factor eIF2 in gastrointestinal carcinomas.

The level of expression and the phosphorylation status of the alpha subunit of initiation factor 2 (eIF2alpha) protein have been determined by comparing samples from human stomach, colon and sigma-rectum carcinomas with normal tissue from the same patients. The unphosphorylated and phosphorylated levels of cytoplasmic eIF2alpha, as well as the percentage of phosphorylated factor over the total, were significantly higher in stomach, colon and sigma-rectum tumours compared with normal tissue. The expression of this factor was also studied by using immunocytochemical methods, where redistribution towards the nucleus in tumour cells as compared with normal tissue was observed. Our results support a likely implication of eIF2alpha in gastrointestinal cancer.

Blue-light regulation of phytoene dehydrogenase (carB) gene expression in Mucor circinelloides.

The carB gene, encoding the phytoene dehydrogenase of Mucor circinelloides, was isolated by heterologous hybridisation with a probe derived from the corresponding gene of Phycomyces blakesleeanus. The cDNA and genomic copies complemented phytoene dehydrogenase defects in Escherichia coli and in carB mutants of M. circinelloides, respectively. Fluence-response curves for transcript accumulation were constructed after different blue-light pulses. The level of carB mRNA accumulation reached values up to 150-fold higher than basal levels in darkness. Several elements in the promoter of this gene resemble a consensus sequence identified in Neurospora crassa (APE) which is essential for blue-light regulation. Comparison of the available phytoene dehydrogenase sequences from plants, fungi, algae and bacteria suggests that the two known types of phytoene dehydrogenase are more closely related to each other than previously thought.

4E binding protein 1 expression is inversely correlated to the progression of gastrointestinal cancers.

Several components of the eukaryotic protein synthesis apparatus have been associated with oncogenic transformation of cells. Overexpression of the initiation factor eIF4E occurs in a variety of human tumours. The aim of this study was to determine the level of expression and the phosphorylation state of eIF4E and 4E-binding protein 1 (4E-BP1) in gastrointestinal cancer, and to ascertain whether or not these factors can be used as diagnostic or prognostic markers within this type of cancer. The eIF4E levels were significantly higher in tumours compared with normal tissue (51. 5+/-4.4 vs 30.9+/-2.5 arbitrary units (A.U.)/mg of protein, p<0.001). However, phosphorylated eIF4E did not change in stomach cancers and decreased in colorectal cancers (67.1+/-1.2 vs 60.8+/-2.8%, p<0.05). 4E-BP1 expression increased in most of the gastrointestinal cancers studied. In addition, an inverse correlation between 4E-BP1 elevation and N and M stages was found, showing significant higher elevation of 4E-BP1 in Node-negative patients (11.21+/-5.74 vs 4. 03+/-2.36 n-fold, p<0.05) as well as in patients without distant metastasis (8.41+/-3.29 vs 0.97+/-0.35 n-fold, p<0.05). These results suggest that 4E-BP1 could function as a tumour suppressor. Moreover, the data show a significant dephosphorylation of 4E-BP1 in gastrointestinal tumours that correlated with an increase in the association of 4E-BP1 and eIF4E indicating a lower availability to eIF4E to recruit to the ribosomes. Our results support a possible role of 4E-BP1 as a prognostic factor in gastrointestinal carcinoma.

Localization of glyoxylate dehydrogenase and glyoxylate-complex molecules in the rat prefrontal cortex: enzymohistochemical and immunocytochemical study.

Glyoxylic acid is synthesized and catabolized in cells of vertebrates; several pathways have been described. In previous papers, we have demonstrated the localization in some areas of the rat cerebral cortex both of beta-NAD-dependent glyoxylate dehydrogenase (glyoDH), using an enzymohistochemical method, and of glyoxylate-complex molecules, using immunocytochemical procedures. In this study we have applied these two techniques in various areas of the prefrontal cortex with different histological cytoarchitecture. GlyoDH has been located in most neurons, in some glial cells, and in capillary wall structures in all cortical layers of all areas of the rat prefrontal cortex. Antibodies against glyoxylate-complex molecules showed positive immunoreactivity in scattered neurons, mostly of multipolar or stellate appearance, from layers III, IV, and V in the medial precentral area, but not in cortical areas 24, 25, or 32 of the prefrontal cortex. Immunoreaction was found in the periphery of neuronal perikarya and in some of their processes. These results demonstrate the existence of a particular area-dependent neuronal cortical system, of specific but uncertain function, related to glyoxylic acid and/or glyoxylate compounds. At the electron microscope level, positive reaction was associated with synaptic sites, axonal filaments, glial cells, and several components of the blood-brain barrier. These localizations suggest the involvement of glyoxylate derivatives in synaptic functioning and also in glial cell functions.

Heterologous expression of the Phycomyces blakesleeanus phytoene dehydrogenase gene (carB) in Mucor circinelloides.

A phytoene dehydrogenase-deficient mutant of Mucor circinelloides accumulating only phytoene was transformed with the gene encoding the corresponding enzyme (carB gene) of Phycomyces blakesleeanus. Carotenoids derived from phytoene were detected in the transformants showing that the P. blakesleeanus carB gene complements the M. circinelloides carB mutation. These newly formed carotenoids accumulated in low quantities, indicating that functional complementation was poor. carB mRNA molecules correctly transcribed were detected in the transformants, but they represented a small proportion of the total population of carB-derived mRNAs, mostly constituted by truncated transcripts and by transcripts longer than the transcript that is functional in Phycomyces. These results showed that the P. blakesleeanus carB gene was expressed in M. circinelloides and suggested that the poor complementation observed was owing, at least in part, to the lack of specificity in the recognition of the transcription initiation and termination signals of the P. blakesleeanus carB gene by the M. circinelloides transcriptional machinery.