[Comparative study of bilateral lesions in the entorhinal cortex and in the fimbria fornix]

INTRODUCTION

Numerous reports show that lesions to hippocampus afferents, such as the entorhinal cortex (EC) and the fimbria fornix (FF), exert an effect on memory in rodents. There are, however, no long term comparative studies that show which of these lesions could be most useful as a model for studies into neuroplasticity.

MATERIAL AND METHODS

Young male Sprague Dawley rats were used. Bilateral electrolytic lesion was caused to the EC or the FF was damaged by transection. One, four or 12 weeks later the animals were evaluated in a Morris water maze, first with an invisible platform and then with the platform within view. The results from the two groups were compared to each other and to those obtained from healthy controls and subjects with false lesions by means of a variance analysis.

RESULTS

In the test with an invisible platform, both types of lesion gave rise to serious, irreparable involvement of the spatial memory of the animals, at least up to 12 weeks after the lesion. The test with the visible platform revealed significant differences between animals with lesion to the EC evaluated at 12 weeks, which suggests the development of some visual or motor deterioration in these animals.

CONCLUSIONS

Although both lesions gave rise to behavioural deterioration that was irreversible in the long term in rodents, the lesion to the FF seems to be a better model for evaluating specific effects on learning and memory, since the lesion to the EC apparently triggers additional sensory and motor involvement.

Follicle-stimulating hormone increases cell proliferation in the ovary and the testis of the chick embryo

Previous studies have demonstrated that FSH stimulates cell proliferation in the ovary and the testis of the chick embryo. This study analyzed the presence of FSH receptor and the cell subpopulations that proliferate in response to FSH in chick embryo gonads. FSH receptor mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) in the male and female gonads of the 6 to 14-day-old chick embryo. Somatic cells of the ovary expressed the FSH receptor in the 14-day-old chick embryo. Ovarian surface epithelium of the 14-day-old chick embryo increased the mitotic index 15-18 h after FSH treatment. Similarly, the mitotic index in oogonia was increased 24 h after receiving a pulse of FSH; this result was confirmed by an increase in the number of germ cells that incorporated bromodeoxyuridine (BrdU). Somatic cells of the medullary cords in the ovary displayed an increase in the mitotic index 15-21 h after the FSH injection. In the chick embryo testis, at the same stage of development, the treatment with FSH increased the mitotic index in cells of the seminiferous tubules and to a lesser extent in cells at a peritubular and interstitial location. Present results demonstrate that in the chick embryo, FSH stimulates the proliferation of ovarian surface epithelium, oogonia in the cortex, and somatic cells of the medullary cords of the chick embryo ovary. In the chick embryo testis, FSH stimulates cell proliferation in seminiferous tubules and peritubular cells.

[The neurobiology of developmental dyslexia: a survey]

One of the most common disorders affecting the ability to read is developmental dyslexia, which, unlike the alexia related to a loss of the capacity to read associated with brain damage, refers to a specific disorder in the acquisition of reading skills and becomes apparent in reiterated persistent difficulties in learning to read. A number of studies have attempted to detect structural and functional abnormalities that might be the origin of problems in learning to read. The use of functional neuroimaging techniques such as positron emission tomography (PET), spectroscopic magnetic resonance imaging (SMRI) and functional magnetic resonance imaging (fMRI) enables us to measure changes in the metabolic activity associated with alterations in the neuronal networks involved in the reading process. In this review, different studies are analysed in an attempt to identify alterations in the cortico subcortical regions which could be the origin of the developmental dyslexia. Results show that in dyslexics there is a temporoparietooccipital disconnection, and a disconnection with the left frontal cortex as regards the demands for fast auditory processing, as well as abnormalities in the connections between the temporoparietal cortex and the cerebellum with other regions of the brain. Such findings suggest that the altered areas of the brain do not only show a characteristic pattern of hypoactivation, but also that these alterations could be the cause of this malady. We highlight the importance of these findings in the diagnosis and rehabilitation of this population.

Angiotensinase activity in hypothalamus and pituitary of hypothyroid, euthyroid and hyperthyroid adult male rats

A local renin-angiotensin system (RAS) that may be involved in their regulatory functions has been identified in hypothalamus and pituitary. Altered thyroid status induces modifications in the secretory function of hypothalamus and pituitary. However, few studies have analyzed the role of the RAS in hypothalamus and, to our knowledge, there is no data on the pituitary RAS during thyroid dysfunction. In the present study, angiotensinase activities (glutamyl, aspartyl and alanyl aminopeptidase: GluAP, AspAP and AlaAP, respectively) were studied in hypothalamus and in the anterior and posterior lobes of pituitary of euthyroid, hypothyroid and hyperthyroid adult male rats. In the anterior pituitary, compared with euthyroid and hyperthyroid rats, hypothyroid animals showed a highly significant increase of GluAP and AspAP activities; the percentage increase in GluAP was markedly higher than the percentage increase in AspAP. This suggests an increased metabolism of angiotensin (Ang) I and Ang II to des-Asp 1-Ang I and Ang III, respectively. We also observed an increase of Ang III-degrading activity (AlaAP) in the hypothalamus of hyperthyroid rats in soluble fraction. Increased Ang I and Ang II metabolism in the anterior pituitary of hypothyroid rats and increased metabolism of Ang III in the hypothalamus of hyperthyroid animals may be related to alterations in the secretory function of hypothalamus and pituitary in these thyroid dysfunctions.

Effects of exogenous fatty acids and cholesterol on aminopeptidase activities in rat astroglia

Several studies have addressed the interaction between fatty acids and lipids with central nervous system peptides. Because aminopeptidases (AP) are involved in the regulation of neuropeptides, this work studies several AP expressed in cultured astroglia, after exogenous addition of oleic and linoleic fatty acids and cholesterol to the culture medium. Alanyl-AP, arginyl-AP, cystyl-AP, leucyl-AP, tyrosyl-AP and pyroglutamyl-AP activities were analysed in whole cells using the corresponding aminoacyl-beta-naphthylamides as substrates. Oleic acid inhibits alanyl-AP, cystyl-AP and leucyl-AP activities, whereas linoleic acid inhibits alanyl-AP, arginyl-AP and tyrosyl-AP activities. Neither oleic acid nor linoleic acid modifies pyroglutamyl-AP activity. In contrast, cholesterol increases arginyl-AP, cystyl-AP, leucyl-AP, tyrosyl-AP and pyroglutamyl-AP activities, although it does not modify alanyl-AP activity. The changes reported here suggest that oleic and linoleic fatty acids and cholesterol can modulate peptide activities via their degradation route involving aminopeptidases; each of them being differentially regulated.

The expression of GABA in mossy fiber synaptosomes coincides with the seizure-induced expression of GABAergic transmission in the mossy fiber synapse

Although the granule cells of the dentate gyrus are glutamatergic, they contain the machinery for the synthesis and vesiculation of GABA. Furthermore, glutamic acid decarboxylase and the vesicular GABA transporter mRNA are expressed in the granule cells and mossy fibers in an activity-dependent manner, suggesting that these cells release GABA in addition to glutamate. Supporting this hypothesis, we found that seizures induce simultaneous glutamatergic and GABAergic transmission in the mossy fiber projection. To further explore this expression of inhibition, we looked for the presence and expression of endogenous GABA in a synaptosomal preparation enriched with mossy fiber nerve endings of kindled rats. We also studied the capacity of this preparation to capture and release [(3)H]GABA under control conditions and after kindling epilepsy. In accordance with our hypothesis we show that the mossy fiber synaptosomal preparation of the kindled rats has a significantly higher content of endogenous GABA than controls. We also found that the protein content in the mossy fiber synaptosomal preparation of kindled rats was significantly augmented, which is consistent with mossy fiber sprouting. Due to this, the total [(3)H]GABA incorporated in the synaptosomal preparation was also augmented. However, [(3)H]GABA uptake (expressed in % radioactivity/mg protein) and its evoked release were similar in both groups. With the present results, we provide further support for the hypothesis of the emergence of GABAergic transmission in the mossy fiber synapse that can constitute a protective mechanism in response to seizures.

Differential effects of dietary cholesterol on aminopeptidase A, B and M in the frontal cortex of male and female mice

Although hypercholesterolemia and hypertension have been extensively associated, the regulatory mechanism underlying this relationship is poorly understood. Systemic and local renin-angiotensin systems are involved in the control of blood-pressure. Angiotensin II has been considered as the main effector peptide of renin-angiotensin system. However, other peptides derived from the metabolism of angiotensin II, as angiotensins III and IV have been shown to play significant roles. The aim of this study is to analyse the effect of dietary cholesterol on the activity of the enzymes involved in the metabolism of angiotensins II and III. Soluble and membrane-bound aminopeptidase A (aspartyl- and glutamyl-aminopeptidases), B (arginyl-aminopeptidase) and M (alanyl-aminopeptidase) activities were measured in the frontal cortex of male and female mice fed a cholesterol enriched-diet (1% cholesterol; 0.5 cholic acid). Soluble and membrane-bound aminopeptidases B and M did not change in male or female cholesterol groups. Significant increases were observed in membrane-bound aspartyl- and glutamyl-aminopeptidase activities in both cholesterol groups. Soluble aspartyl- and glutamylaminopeptidases did not change in male cholesterol group, but significant decreases were detected in female cholesterol group. Our results may indicate that the metabolism of angiotensin II to angiotensin III by aminopeptidase A is increased, but angiotensin III metabolism by aminopeptidases B and M is not modified after cholesterol intake; so cholesterol may enhance the effects of angiotensin III, at least, at the cortical level.

[Benign prostatic hyperplasia: biological significance of lymphohistiocytic infiltration of the adenoma]

The presence of mononuclear cells infiltrating the prostate adenoma is a morphological observation well established in the literature. However, its biological meaning is a subject of controversy. It has been postulated that it may represent a local immunological reaction contributing to the pathogenesis of prostatic adenoma. Several studies have been performed to test this hypothesis, both in humans and animals. The purpose of this review is to update available information, including our own ongoing studies. Morphological research has shown that cells infiltrating the adenoma are lymphocyte T, lymphocyte B and macrophages with a high proportion of lymphocyte T. Many of the inflammatory markers, such as lymphoquines (IL1, IL2, IL4, IL6, IL13), are elevated in the adenoma tissue as are some growth factors (EGF, TGF alpha, IFN gamma, TGF beta). The general impression is that an inflammatory process is activated in the adenoma during growth and maturing. It has also been proved that this inflammatory process could be modified with treatment and, in our case, with the lipido-sterolic extract of Serenoa Repens.

Pituitary aminopeptidase activities involved in blood-pressure regulation are modified by dietary cholesterol: sex differences

Given that the existence of a local renin-angiotensin system (RAS) in the pituitary and its participation in the regulation of blood pressure and other biological functions are widely accepted, the aim of this work is to analyze the influence of dietary cholesterol on the activity of the enzymes involved in the metabolism of the effector peptides of the renin-angiotensin system (angiotensin II and III) and vasopressin, in the pituitary of male and female mice fed on a cholesterol-enriched diet (1% cholesterol and 0.5% cholic acid). Soluble and membrane-bound pituitary aminopeptidase A (aspartyl- and glutamyl-aminopeptidase), aminopeptidase M (alanyl-aminopeptidase), aminopeptidase B (arginyl-aminopeptidase) and cystinyl-aminopeptidase activities were fluorimetrically measured. In female mice, cholesterol-enriched diet produced a significant increase in soluble aspartyl- and membrane-bound aspartyl- and glutamyl-aminopeptidase activities, and a significant decrease in membrane-bound alanyl-, arginyl- and cystinyl-aminopeptidase activities. In male mice, after feeding the diet, a significant increase in soluble glutamyl- and membrane-bound arginyl-aminopeptidase activities was observed. Our results indicate differential effects of dietary cholesterol on the metabolism of angiotensin II and III and vasopressin in the pituitary of male and female mice.

Dietary long-chain polyunsaturated fatty acids from different sources affect fat and fatty acid excretions in rats

Several sources of long-chain polyunsaturated fatty acids (LCP) have been evaluated for infant-formula supplementation. These sources differ in their chemical structure [triglyceride (TG) or phospholipid (PL)], arrangement of fatty acids on the TG or PL backbone, fatty acid composition and presence of other lipid components. All of these characteristics influence fat digestion, may affect fat and fatty acid absorption, and hence, LCP bioavailability and metabolism in infancy. The main objective of this work was to establish the influence of different dietary LCP sources on overall fat and LCP absorption in early life. We compared fat and fatty acid excretions at weaning in rats fed control diets or diets supplemented with LCP as TG or PL. Two separate experiments were conducted. In Experiment 1, weanling rats were fed for 3 wk a control diet (C1), a diet with TG from tuna and fungal oils (TF-TG) or a diet with PL from pig brain concentrate (PB-PL). In Experiment 2, weanling rats were fed for 3 wk a control diet (C2), a diet containing egg-TG (EG-TG) or a diet containing egg-PL (EG-PL). Fat, mineral and saturated fatty acid excretions in feces were higher in rats fed PB-PL compared with those fed TF-TG diet. In Experiment 2, groups did not differ in fat and mineral excretions. However, the EG-PL group had lower fecal excretions of saturated fatty acids than the C2 and EG-TG groups. The 16:1(n-7), 18:1(n-9), 18:2(n-6) and 22:6(n-3) levels in feces were higher in the EG-TG group than in the EG-PL group. In summary, total fat and LCP excretions differed among rats fed diets supplemented with LCP from different sources.

Activity-dependent expression of GAD67 in the granule cells of the rat hippocampus

In the normal granule cells of the dentate gyrus glutamate, GABA and glutamic acid decarboxylase (GAD67) coexist. After kindled seizures, this enzyme is transiently overexpressed and simultaneous glutamatergic and GABAergic transmission in the mossy fiber projection occurs. Since this dual transmission is also seen after acutely-induced seizures, we decided to study the relationship between the expression of GAD67 and the induction of simultaneous glutamatergic and GABAergic transmission by kindled or acutely induced seizures. We also explored whether kindling of the dentate gyrus in vitro, that does not induce epileptiform activity, could induce the expression of GAD67. We confirm that kindling epilepsy induces the expression of GAD67 in the dentate gyrus. Despite the emergence of GABAergic transmission in the mossy fiber projection after a single seizure, GAD67 expression in the dentate gyrus appeared similar to controls, however, in the mossy fibers an enhanced immunostaining was evident. Interestingly, kindling the dentate gyrus in vitro induces a marked GAD67 staining in the granule cells. Our results show that after the activity-dependent emergence of simultaneous glutamatergic and GABAergic transmission from the mossy fibers, GAD67 is expressed in the mossy fibers and, upon long-lasting enduring stimulation periods, also in the dentate gyrus. Thus, this phenomenon does not depend on the presence of epileptic activity, but rather, on increased excitatory input onto the dentate gyrus. This can represent a protective mechanism that can sustain GABA synthesis in an activity-dependent manner.

Absorption and distribution of dietary fatty acids from different sources

Lipids have physical, chemical, and physiological properties that make them important factors in human nutrition. They form a group of compounds of varied chemical nature that have the common property of being soluble in organic solvents but insoluble in water. This basic property affects their digestion, absorption, and transport in the blood and metabolism at cellular level. Firstly, fatty-acid chain length and number of double bonds influence fat absorption. Thus, medium-chain fatty acids (MCFA) are better absorbed than long-chain fatty acids. Secondly, the positional distribution of fatty acids (FA) in dietary triglycerides (TG) determine whether FA are absorbed as 2-monoglycerides (2-MG) or free fatty acids (FFA), and hence, influences the composition of chylomicroms (CM) because triglycerides (TG) are resyntethysed in the intestinal mucosa using 2-MG from dietary lipids. Generally, the absorption of FA in the sn-2 position of TG is favored, whereas no specificity has been found for the fatty acids in the sn-1 and sn-3 positions. Finally, some FA of nutritional interest, namely, long-chain polyunsaturated fatty acids (LCP), are present in dietary lipid sources as both TG or phospholipids (PL). Fatty acids esterified as PL or TG may show different availability. In fact, some authors have suggested a better absorption of LCP-PL. Moreover, dietary LCP in form of TG or PL differently affects the composition of HDL and LDL PL.

Ex vivo expansion of umbilical cord blood (UCB) CD34(+) cells alters the expression and function of alpha 4 beta 1 and alpha 5 beta 1 integrins

We have investigated the influence of ex vivo expansion of human CD34(+) cord blood cells on the expression and function of adhesion molecules involved in the homing and engraftment of haematopoietic progenitors. Ex vivo expansion of umbilical cord blood CD34(+) cells for 6 d in the presence of interleukin 3 (IL-3), IL-6 and stem cell factor (SCF) or IL-11, SCF and Flt-3L resulted in increased expression of alpha 4, alpha 5, beta 1, alpha M and beta 2 integrins. However, a significant decrease in the adhesion of progenitor cells to fibronectin was observed after the ex vivo culture (adhesion of granulocyte-macrophage colony-forming units (CFU-GM) was 22 +/- 4% in fresh cells versus 5 +/- 2% and 2 +/- 2% in each combination of cytokines). Incubation with the beta 1 integrin-activating antibody TS2/16 restored adhesion to fibronectin. Transplantation of ex vivo expanded umbilical cord blood CD34(+) cells was associated with an early delayed engraftment in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. Incubation of cells with the monoclonal antibody TS2/16 before transplantation almost completely abrogated NOD/SCID repopulating ability of both fresh and expanded CD34(+) cells. The seeding efficiency of fresh and expanded CD34(+) cells was similar, but markedly reduced after incubation with the TS2/16 monoclonal antibody. Our results show that functional activation of beta 1 integrins could overcome the decreased very late antigen (VLA)-4- and VLA-5-mediated adhesion observed after ex vivo expansion of haematopoietic progenitors. However, in vivo, these effects induced an almost complete abrogation of the homing and repopulating ability of CD34(+) UCB cells.

Acetylcholinesterase inhibitor SDZ ENA 713 (Rivastigmine) increases brain pyrrolidone carboxyl peptidase activity

Pyroglutamyl-ended forms of amyloid-beta-peptide are present in senile plaques in some individuals with Alzheimer type dementia. Single oral administration of the acetylcholinesterase inhibitor SDZ ENA 713 (rivastigmine (+)-(S)-N-ethyl-3-[(1-dimethylamino)ethyl]-N-methylphenylcarbamate hydrogen tartrate) increases basal and K(+)-stimulated pyrrolidone carboxyl peptidase (Pcp) activity in mice frontal cortex synaptosomes in a dose-dependent manner. These results suggest that this drug may ameliorate ATD cognitive deficits acting not only facilitating cholinergic transmission but also avoiding the formation of pyroglutamyl-ended amyloid-beta-peptides (A beta pE) deposition through the activation of Pcp.

Laryngotracheal reconstruction in subglottic stenosis: an ancient problem still present

BACKGROUND

Subglottic stenosis is an ancient but persistent problem as a cause of airway obstruction. The etiology and the results of surgical treatment with thyrotracheal anastomosis were reviewed.

METHODS

Fifty-six patients with subglottic stenosis were studied. All were subjected to laryngotracheal reconstruction by thyrotracheal anastomosis with partial resection of the cricoid.

RESULTS

Of all 56 cases of subglottic stenosis, 48 (86%) had history of previous tracheal intubation, and only 8 (14%) had different non-neoplastic obstructive processes such as scleroma, direct injury, hamartoma, and amyloidosis. Immediate results were good in all cases. After 1 year follow-up, results of thyrotracheal anastomosis were successful in 44 (91%). In 4 other cases a restenosis was observed. Eight patients were lost to follow-up.

CONCLUSIONS

Subglottic stenosis is still frequent after tracheal intubation, but other causes must be considered. Laryngotracheal reconstruction with thyrotracheal anastomosis with partial cricoid resection was feasible with good results in 91% of the cases with follow-up, but this procedure must be performed by a skilled surgical team.

Aminopeptidase activities after water deprivation in male and female rats

Aminopeptidases (APs) play a major role in the metabolism of circulating and local peptides, such as angiotensins and vasopressin, substances involved in the control of blood pressure and water balance. In the present work, we studied the influence of dehydration on angiotensinases and vasopressin-degrading activity. Since sex differences may exist in the regulation of water balance by angiotensin II and differential sexual steroid modulation of vasopressin secretion, in response to osmotic stimulation have been reported, gonadotropin releasing hormone (GnRH)-degrading activity was also analysed in serum, neurohypophysis and adrenal glands of male and female rats. Our results did not suggest sex differences in the response to changes in osmolality. GnRH-degrading activity decreased in serum of dehydrated males and females, which suggests a longer action of the peptide under these conditions. In neurohypophysis, there was an increase in the activity of aminopeptidase A (APA), the enzyme responsible for the metabolism of angiotensin II to angiotensin III. This occurs with a decrease in alanyl aminopeptidase activity, which would lead to a prolonged action of angiotensin III by reduction of its metabolism. In adrenals of dehydrated animals, the results would imply a high degree of metabolism of angiotensin III and vasopressin.

Influence of killer strains of Saccharomyces cerevisiae on wine fermentation

The effect of killer strains of Saccharomyces cerevisiae on the growth of sensitive strains during must fermentation was studied by using a new method to monitor yeast populations. The capability of killer yeast strains to eliminate sensitive strains depends on the initial proportion of killer yeasts, the susceptibility of sensitive strains, and the treatment of the must. In sterile filtered must, an initial proportion of 2-6% of killer yeasts was responsible for protracted fermentation and suppression of isogenic sensitive strains. A more variable initial proportion was needed to get the same effect with non-isogenic strains. The suspended solids that remain in the must after cold-settling decreased killer toxin effect. The addition of bentonite to the must avoided protracted fermentation and the suppression of sensitive strains; however, the addition of yeast dietary nutrients with yeast cell walls did not, although it decreased fermentation lag.

Effect of valsartan on angiotensin II- and vasopressin-degrading activities in the kidney of normotensive and hypertensive rats

Valsartan, a selective antagonist of angiotensin II at the AT(1) receptor subtype, is an efficacious, orally active, blood pressure-lowering agent used in hypertensive patients. Given that aminopeptidases (APs) play a major role in the metabolism of local peptides involved in blood pressure control, studying them helped us to understand cardiovascular control. We studied the effect of valsartan on angiotensin II- (GluAP) and vasopressin- (CysAP) degrading activities in the kidney in the rat model of renovascular hypertension, Goldblatt two-kidney one-clip. GluAP and CysAP in renal cortex and medulla exhibited different responses to hypertension and valsartan treatment. In the renal cortex, GluAP decreased in clipped and non-clipped kidneys of hypertensive animals. However, while hypertension did not affect GluAP in the clipped kidney medulla, the non-clipped kidney exhibited an increase in soluble and a decrease in membrane-bound activity. Valsartan decreased soluble GluAP in the medulla of normotensive and hypertensive animals. In the renal cortex, CysAP activity was mainly downregulated following hypertension. Valsartan decreased soluble CysAP activity in sham-operated, but not in hypertensive animals. The renal medulla showed a significant valsartan-related decreased activity in clipped and non-clipped kidneys of both sham-operated and hypertensive animals. These results suggest a functional relationship between the AT(1) receptor and vasopressin-degrading activity.

[Influence of estradiol on pyroglutamyl aminopeptidase activity in the frontal cortex of ovariectomized mice]

INTRODUCTION

Pyroglutamyl aminopeptidase (pGluAP) is an omega peptidase widely distributed in fluid and tissues which hydrolyses biological active peptides including thyrotropin releasing hormone (TRH). OBJECTIVES. The aim of present work is to study the influence of estradiol on soluble and membrane bound pGluAP activity in the frontal cortex of female mice.

MATERIAL AND METHODS

Soluble and membrane bound pGluAP activities in frontal cortex of ovariectomized mice and ovariectomized mice injected with different doses of estradiol were measured using espectrophotometric assays.

RESULTS

Soluble pGluAP activity in frontal cortex did not change after ovariectomy or after the administration of the different doses of estradiol. However, membrane bound pGluAP activity showed a significant increase after ovariectomy. After the administration of the lower dose of estradiol, membrane bond pGluAP activity returned to the same levels detected before the ovariectomy.

CONCLUSION

Estradiol modifies membrane bound pGluAP activity which is the principal enzyme involved in the hydrolysis of TRH. Therefore, misregulation of estradiol levels may produce modifications in the neuromodulatory functions of TRH.

[Influence of alcohol on brain aminopeptidases. An in vitro study]

INTRODUCTION

It is well known the depressor effect of alcohol on several inhibitory nervous centres. This can be due to the inhibition that induces in the release of different type of neurotransmitters, and because alcohol can increase the membrane fluidity and changes the function of proteins inserted in the membrane. Several aminopeptidases (AP) have been described as enzymes that regulate the activity of peptide neurotransmitters. In the present work, the influence of alcohol (25, 50 and 100 mM) on several aminopeptidase activities (alanyl AP, arginyl AP, cystinyl AP, leucyl AP and tyrosyl AP) has been determined in synaptosomes obtained from the cortex of mouse, under basal and K+ stimulated conditions and their calcium dependence, in a non toxic in vitro model.

MATERIAL AND METHODS

AP activities were determined using aminoacyl ? naphthylamides as substrates. Non toxic in vitro model were demonstrated analyzing free radical generation, lipid peroxidation and oxidation of synaptosomal proteins. In addition, the bioenergetic behavior of synaptosomes was determined under different experimental protocols.

RESULTS

In basal conditions, alcohol produces a dose related inhibition of alanyl AP activity. The rest of activities show a biphasic behavior. In this way, depending on the concentration of alcohol used, aminopeptidases are inhibited or stimulated. Depolarization with K+ 25 mM leads to a decrease of alanyl AP and tyrosyl AP activities but does not change the rest of activities. The presence of alcohol under stimulated conditions produces the inhibition of all the enzymatic activities, specially with the highest concentrations used.

CONCLUSIONS

Alcohol modifies several aminopeptidase activities from synaptosomes of the cortex of mouse, acting in different ways under basal or stimulated conditions. These effects seem not to be related with degenerative events induced by alcohol. Therefore, a specific effect of this substance on the neurotransmisory/neuromodulatory systems mediated by neuropeptides must exist, modifying the enzymes that are responsible of their degradation.

Angiotensinase activity in mice fed an olive oil-supplemented diet

We evaluated the influence of a diet supplemented with olive oil (20% by weight) (OO) on the activity of glutamyl aminopeptidase (GluAP) and aspartyl aminopeptidase (AspAP), which are involved in angiotensin metabolism. Serum concentrations of total cholesterol and fatty acids were also measured. Animals fed on the OO diet gained significantly more weight than did controls from the second week until the end of the feeding period. Serum total cholesterol concentration was significantly higher in the OO group than in control mice. Total monounsaturated fatty acids increased in OO-fed animals, but total saturated fatty acids decreased. No differences between the two groups were observed for total polyunsaturated fatty acids. Serum from animals fed on the OO diet contained significantly lower proportions of myristic, pentadecanoic, palmitic, palmitoleic, vaccenic, alpha-linolenic, gamma-linolenic, and 11,14-eicosadienoic acids than did serum from control animals. In contrast, the OO group had higher levels of oleic, stearic, and gondoic acids. GluAP activity decreased significantly in the serum of OO-fed animals. In these animals soluble AspAP activity was significantly higher in the testis, and significantly lower in the lung and adrenal, in comparison to controls. Membrane-bound AspAP activity was higher in the testis and atrium, and lower in lung, in the OO group. Soluble GluAP activity was significantly lower in the testis of OO-fed animals. Membrane-bound GluAP activity did not differ between the two groups in any of the tissues analyzed. Serum AspAP and GluAP activities correlated negatively with palmitoleic and vaccenic acid respectively in the OO group. However, no significant correlations were found in the control group. These results may reflect functional changes in the renin-angiotensin system in the serum, adrenal, testis, lung and atrium after feeding with a diet enriched in olive oil.

An unusual presentation of opioid-like syndrome in pediatric valproic acid poisoning

We report a 3-y-o boy who accidentally poisoned himself with valproic acid (VPA). Clinical features included profound coma, depressed respiration and miosis. Treatment included naloxone, gastric lavage, and activated charcoal and a saline cathartic. The patient fully recovered and was discharged 24 h after the admission. Prompt use of naloxone is advised whenever the triad of coma, pinpoint pupils and depressed respiration concur with the clinical possibility of VPA intoxication.

[Dietary cholesterol modifies pyroglutamyl aminopeptidase activity in mouse frontal cortex. Sexual differences]

INTRODUCTION

Pyroglutamyl aminopeptidase (pGluAP) is an omega peptidase widely distributed in fluid and tissues, which hydrolyses biological active peptides including thyrotropin-releasing-hormone (TRH). In the last years, different endocrine and extraendocrine functions have been attributed to TRH.

OBJECTIVES

The aim of present work is to study the influence of high dietary cholesterol on soluble and membrane bound pGluAP activity in frontal cortex of male and female mice. Material and methods. Soluble and membrane bound pGluAP activities of frontal cortex of mice feeding during 15 days, a standard diet enriched with cholesterol (1%) and cholic acid (0.5%) were measured using fluorimetric assays.

RESULTS

Significant increases were observed in membrane bound pGluAP activity in males and females. No changes were detected in soluble pGluAP activity in frontal cortex of females but a significant increase was observed in this enzymatic activity in males.

CONCLUSIONS

High dietary cholesterol induces a significant increase in tissue pGluAP activity. These increases may produce changes in TRH metabolism which may be related with alterations in its neuromodulatory functions and with the possible relationship between TRH and other neurotransmitter systems.

Environmental light-darkness conditions induce changes in brain and peripheral pyroglutamyl-peptidase I activity

To evaluate the influence of light and darkness on brain pyroglutamyl-peptidase I (pGluPI) activity, four experimental groups of rats were compared at the same time-point (10.00 h). Two groups were designed with a standard 12-12 h light-dark cycle: In group A, the lights were on from 7.00 h to 19.00 h, and the experiment was done under light conditions; in group B, the lights were on from 19.00 h to 7.00 h, and the experiment was done under darkness conditions. Two additional groups were designed with nonstandard light-dark conditions: In group C, the animals were subjected to constant light, and the experiment was done under light conditions. In group D, animals were subjected to constant darkness, and the experiment was done under darkness conditions. Light (vs darkness) and standard (vs nonstandard) conditions produced significant changes on pGluPI activity in specific structures; the data suggested that endogenous substrates of pGluPI such as thyrotropin-releasing hormone and gonadotropin-releasing hormone, might be modified in parallel. There was left predominance in the retina under light conditions on a standard schedule (group A). The regional pattern of distribution of activity was similar in groups on a standard schedule (A vs B) and in groups tested under constant light-dark conditions (C vs D). However, this pattern differed between groups subjected to standard vs constant light-dark conditions (A and B vs C and D). These results support an influence of environmental light and darkness on pGluPI activity, which may reflect concomitant changes in its susceptible substrates and consequently in their functions.

Feeding infant piglets formula with long-chain polyunsaturated fatty acids as triacylglycerols or phospholipids influences the distribution of these fatty acids in plasma lipoprotein fractions

Several sources of long-chain polyunsaturated fatty acids (LCP) are currently available for infant formula supplementation. These oils differ in their fatty acid composition, the chemical form of the fatty acid esters [triacylglycerols (TG) or phospholipids (PL)] and presence of other lipid components. These differences may affect LCP absorption, distribution and metabolic fate after ingestion. The purpose of the present study was to evaluate the influence of different chemical forms of dietary LCP on the composition of plasma, plasma lipoproteins, liver and jejunum in infant piglets. Thirty pigs (5 d old) were bottle-fed different diets for 4 wk: a control diet (C), a diet containing LCP as TG from tuna and fungal oils (TF-TG) or a diet containing LCP as PL from egg yolk (E-PL). We measured lipid and fatty acid composition of plasma and lipoproteins, as well as lipid composition of liver and intestinal mucosa. The arachidonic and docosahexaenoic acids in HDL-PL were significantly higher in piglets fed the E-PL diet than in those fed the TF-TG diet. Opposite results were found in the LDL-PL diet. No significant differences were found between groups in TG or cholesterol concentrations of plasma or lipoproteins. Arachidonic acid in plasma PL and cholesteryl esters was significantly higher in the E-PL group than in the TF-TG group. The chemical form in which LCP esters are present in different dietary sources influences their distribution in plasma lipoproteins. This may be important for infant nutrition and suggests that not all LCP sources may be biologically equivalent.

Serum aminopeptidase A activity of mice is related to dietary fat saturation

A high intake of monounsaturated fat has been proposed to be a dietary factor that can decrease the incidence of cardiovascular disease and hypertension. In addition, increasing dietary fat saturation has been shown to increase plasma total cholesterol and elevate systolic and diastolic blood pressures. We demonstrated previously that cholesterol selectively increases in vitro aminopeptidase A activity, which is related to angiotensin metabolism. In this study, we investigated the effect of different degrees of dietary fatty acid saturation on serum aminopeptidase activities in vivo. Serum total cholesterol concentrations were also measured. Five groups of male Balb/C mice were fed for 10 wk diets containing 2.4 g/100 g of sunflower oil, fish oil, olive oil, lard or coconut oil. We measured alanyl-, arginyl-, cystinyl-, pyroglutamyl-, aspartyl- and glutamyl-specific aminopeptidase activities using arylamides as substrates. Serum total cholesterol levels were higher in mice fed diets containing saturated oils (lard and coconut) than in those consuming sunflower oil, which is unsaturated. Two of the serum aminopeptidase A activities (aspartyl and glutamyl aminopeptidase) increased progressively with the degree of saturation of the dietary fatty acids; activities were significantly greater in mice fed coconut oil than in those fed sunflower or fish oil. Therefore, the substrates hydrolyzed by this activity as well as their functions may be similarly affected. These results may have some implication for the treatment of cardiovascular disease.

Plasma fatty-acid composition and antioxidant capacity in low birth-weight infants fed formula enriched with n-6 and n-3 long-chain polyunsaturated fatty acids from purified phospholipids

OBJECTIVE

To determine whether a formula containing n-6 and n-3 long-chain polyunsaturated fatty acids (LCP) from purified phospholipids increases the content of 20:4n-6 and 22:6n-3 of plasma lipids and modifies the plasma antioxidant capacity in low-birth-weight infants.

STUDY DESIGN

Seventeen infants were fed a conventional formula for low birth-weight infants (F), and 17 a formula containing n-6 and n-3 LCP from purified pig-brain phospholipids (LCP-F). Fourteen infants receiving human milk from a human milk bank were used as a reference (HM). Growth index were measured and blood samples were taken at entry and after 15 days and 30 days of feeding.

RESULTS

In infants fed LCP-F the levels of 22:6n-3 in total plasma lipids and in plasma phospholipids and triglycerides were higher than in infants fed F and closer to the levels of HM group throughout the study. Docosahexaenoic acid concentration in total plasma lipids was 3.46+/-0.19 mg/dl in infants fed LCP-F and 2.08+/-0.20 in infants fed F after 15 days of feeding (P<0.001), and 3.83+/-0.30 and 2.15+/-0.20 in infants fed LCP-F and F respectively, after 30 days of feeding (P<0.001). The concentration of 20:4n-6 in the LCP-F was significantly higher than in the F group at 15 and 30 days of feeding. Plasma antioxidant capacity did not differ significantly between the study groups.

CONCLUSION

Feeding low birth-weight infants a formula containing LCP phospholipids results in an increase of n-3 and n-6 LCP in plasma towards that of infants fed human milk.

Oleate, linoleate and cholesterol differently modify aspartyl- and glutamyl-aminopeptidase activities in primary cultures of rat astrocytes

The intake of mono- and polyunsaturated fatty acids has been associated with a minor risk of cardiovascular diseases including hypertension. Changes in levels of fatty acids may also modify the cell activity and may be related with alterations in different regulatory processes. Aminopeptidases are zinc-metalloenzymes which metabolise circulating peptide hormones in several tissues. Glutamyl-aminopeptidase (GluAP) and to a lesser extent, aspartyl-aminopeptidase (AspAP), are related with angiotensin metabolism in the renin-angiotensin system. The present work was designed to study the effect of a range of concentrations (1-100 microM) of oleic and linoleic acids and cholesterol present in the culture medium on the activity of GluAP and AspAP in the culture of rat cerebral cortical astrocytes taken from 21-day-old fetuses. The results showed that oleic acid inhibits, while linoleic acid stimulates the activity of AspAP. Both fatty acids inhibit the activity of GluAP. Cholesterol stimulates the activity of both enzymes. On the basis of these results, a functional link may exit between the effects of fatty acids on hypertension and the modulation of aminopeptidase activity by these compounds in rat astrocytes, as an example of target cell type in the central nervous system.

Osteopenia in Puerto Ricans with Crohn's disease

BACKGROUND

Osteopenia has been reported in association to Inflammatory Bowel Disease, and in particular Crohn's disease. The use of corticosteroids, resection of the ileum, malabsorption, poor calcium intake, and the effect of inflammatory cytokines have all been considered as contributing factors. As Crohn's disease is more prevalent in young people, when peak bone mass is achieved, the presence of osteopenia is especially significant.

OBJECTIVES

The aim of this study was to evaluate the bone density of patients with Crohn's disease in the University of Puerto Rico IBD Clinic; to determine the prevalence of osteopenia in these patients and to correlate bone mineral density with risk factors for osteopenia.

METHODS

Sixty-six patients, 30 males and 36 females were included. After informed consent, demographic, clinical and metabolic data was obtained. Serum albumin, calcium, inorganic phosphorus and alkaline phosphatase were measured. Body mass index (BMI) was calculated. Bone density was determined by DEXA of the lumbar spine and femur and expressed as the Z score (standard deviations from normal correlated with sex and age). Severe osteopenia was a Z score > or = -2 and osteopenia was Z < or = -1.99 or > or = 1.01. Results were expressed in means. Pearson correlation coefficient was used for quantitative variables and Pearson chi-square for categorical values.

RESULTS

Osteopenia was present in the hip in 69% and in the lumbar spine in 68%. Most patients had received steroids; the difference between treated and not treated patients was not significant. Osteopenia did not correlate with ileal resection, gender, BMI, disease characteristics or biochemical parameters.

CONCLUSIONS

Low bone density was frequent in patients with Crohn's disease, but no specific risk factors could be identified. Bone density should be determined in patients with Crohn's disease in order to institute appropriate therapeutic measures.

Calcium-dependent modulation by ethanol of mouse synaptosomal pyroglutamyl aminopeptidase activity under basal and K(+)-stimulated conditions

We studied the in vitro effects of ethanol (25, 50 and 100 mM) on pyroglutamyl aminopeptidase activity (pGluAP), which has been reported as thyrotrophin-releasing-hormone-degrading activity. pGluAP was measured in presence or absence of calcium, under basal and K(+)-stimulated conditions, in synaptosomes and their incubation supernatant, using pyroglutamyl-beta-naphthylamide as substrate. In basal conditions, in synaptosomes, pGluAP was inhibited by ethanol in a calcium-independent way. In the supernatant, the response differed depending on the concentration of ethanol. Depolarization with K(+) modified pGluAP in synaptosomes and supernatant depending on the presence or not of calcium. In synaptosomes, in absence of calcium, the activity was inhibited at the highest concentrations of ethanol. In contrast, in the supernatant, under depolarizing conditions, ethanol increases pGluAP in absence of calcium. These changes may be in part responsible of the behavioural changes associated to alcohol intake.

[Clinical experience in home care of children with tracheostomy]

BACKGROUND

Home care of tracheostomized children is considered a safe and low-cost alternative.

AIM

To report the experience with tracheostomized children at the Pediatric Respiratory Unit of the Catholic University Hospital.

PATIENTS AND METHODS

The records of 16 children (9 male) with tracheostomy (TQ) in home care between 1992 and 1998 were reviewed.

RESULTS

The average age at the moment of TQ was 9 months (range 1-30 months) and the postoperative hospital management period was 5 months (range 1-11 months). The average age at discharge was 13 months (range 3 to 30 months). Surgical indication were upper airway obstruction (congenital or acquired subglottic stenosis in three, upper airway malformations in one, vocal cord palsy in one and tracheobronchomalacia in one) and chronic assisted ventilation (severe tracheobronchomalacia in four, pulmonary hypoplasia in two, myopathy in one, central nervous injury in one and bronchopulmonary dysplasia in one). Overall rate complications were 2 per 100 tracheostomy months during home care and 8 per 100 tracheostomy months during hospital care. No tracheostomy-related deaths were observed. A parenteral education program to teach about tracheostomy management and cardiopulmonary resuscitation was carried out.

CONCLUSIONS

Tracheostomized children can be safely managed at home.

Gestational age and origin of human milk influence total lipid and fatty acid contents

The human milk composition may be influenced by several factors, such as gestational age or genetic characteristics and dietary habits of different populations. To analyze the total lipid and fatty acid contents of human milk, we have conducted two studies, one on mothers who had delivered preterm and term newborns and another on mothers from two different sociocultural backgrounds (Spain and Panama). The total lipid content (g/100 g wet weight) was significantly higher in term (2.76 +/- 0.66; mean +/- SD) than in preterm mature milk (1.06 +/- 0.4). The relative amount of 18:1n-9 was significantly higher in preterm than in term milk for transitional and mature milk, whereas that for the colostrum followed the opposite trend. Concerning the comparison between milk from mothers born in different countries, the relative contents of each of the fatty acids 16:0, 16:1n-7, 18:2n-6, 18:3n-3, and 22:5n-3 were higher in Panamanian than in Spanish milk, whereas the mean percentages of saturated fatty acids < 14:0, of 16:1n-9, and of 18:1n-9 were higher in Spanish than in Panamanian milk. Statistically significant differences were found during the three periods of lactation considered for almost all the fatty acids mentioned above, especially for 18:1n-9 and 18:3n-3. Although the potential biological significance of the changes in oleic acid content between preterm and term milk remains unclear, differences in fatty acid content between Spanish and Panamanian milk reflect the different composition of the diet among women from these countries.

The application of single cell gel electrophoresis or Comet assay to human monitoring studies

OBJECTIVE

In the search of new human genotoxic biomarkers, the single cell gel electrophoresis assay has been proposed as a sensible alternative.

MATERIAL AND METHODS

This technique detects principally single strand breaks as well as alkali-labile and repair-retarded sites.

RESULTS

Herein we present our experience using the single cell gel electrophoresis assay in human population studies, both occupationally and environmentally exposed.

CONCLUSIONS

We discuss the assay feasibility as a genotoxic biomarker.

Oral administration of losartan influences aminopeptidase activity in the frontal cortex

Although there is a brain renin-angiotensin system, its mechanisms of control are not fully understood. We studied the effect of oral administration of the AT(1) receptor antagonist losartan on brain aminopeptidase (AP) activity, which plays a major role in neuropeptide metabolism. Six AP activities, related and non-related with the angiotensin (Ang) metabolism, were measured in their soluble and membrane-bound forms in the frontal cortex of control animals and rats treated with losartan, chronically administered via the drinking water. The results demonstrate that soluble pGluAP and membrane-bound AspAP and GluAP increased significantly in losartan-treated animals, indicating that the blockade of the AT(1) receptor stimulates the activity of AP involved in the Ang metabolism. Moreover, the blockade of the AT(1) receptor induces changes not only in the brain angiotensin metabolism, but probably also in that of other neuropeptides.

[Aminoglycoside antibiotics neomycin and kanamycin inhibit the increase of of pyroglutamyl aminopeptidase activity by depolarizing synaptosomes of the frontal cortex of the rate]

INTRODUCTION

Thyrotrophin releasing hormone (TRH) has emerging in the last few years as a neuropeptide with important functions, not only as neurohormone into the hypothalamus-pituitary axis, but as neurotransmitter in several areas of the nervous system. Although little is known about its extra-endocrine functions, TRH has been related with several types of psychiatric disorders. Pyroglutamyl aminopeptidase (pGluAP) is the enzyme involved in the degradation of TRH.

OBJECTIVES

The present research studies the levels of pGluAP activity under basal (resting) and KCl-stimulated (depolarized) conditions. The role of intracellular free calcium homeostasis, by means of the aminoglycoside antibiotics neomycin and kanamycin as voltage-dependent calcium channels blockers, is also studied.

MATERIAL AND METHODS

Both pGluAP activity and intracellular free calcium concentration were analyzed in synaptosomes obtained from the frontal cortex of rats. Synaptosomes were incubated in artificial cerebrospinal fluid, under basal (resting) or KCl-stimulated (depolarized) conditions, with of without neomycin or kanamycin at different concentrations.

RESULTS

Depolarization increases significantly pGluAP activity, which is completely abolished by neomycin and kanamycin at the lower concentrations used. On the contrary, aminoglycoside antibiotics do not block completely the increase on intracellular free calcium concentration induced by depolarization. Under basal conditions, no changes were found on pGluAP activity nor intracellular free calcium.

CONCLUSIONS

pGluAP activity could regulate the neurotransmitter/neuromodulatory functions of TRH trough intracellular free calcium movements through aminoglycoside-sensitive voltage-dependent calcium channels. A role for inositol 4,5-bisphosphate breakdown products is also suggested.

Efficient transduction of human hematopoietic repopulating cells generating stable engraftment of transgene-expressing cells in NOD/SCID mice

In an attempt to develop efficient procedures of human hematopoietic gene therapy, retrovirally transduced CD34(+) cord blood cells were transplanted into NOD/SCID mice to evaluate the repopulating potential of transduced grafts. Samples were prestimulated on Retronectin-coated dishes and infected with gibbon ape leukemia virus (GALV)-pseudotyped FMEV vectors encoding the enhanced green fluorescent protein (EGFP). Periodic analyses of bone marrow (BM) from transplanted recipients revealed a sustained engraftment of human hematopoietic cells expressing the EGFP transgene. On average, 33.6% of human CD45(+) cells expressed the transgene 90 to 120 days after transplantation. Moreover, 11.9% of total NOD/SCID BM consisted of human CD45(+) cells expressing the EGFP transgene at this time. The transplantation of purified EGFP(+) cells increased the proportion of CD45(+) cells positive for EGFP expression to 57. 7% at 90 to 120 days after transplantation. At this time, 18.9% and 4.3% of NOD/SCID BM consisted of CD45(+)/EGFP(+) and CD34(+)/EGFP(+) cells, respectively. Interestingly, the transplantation of EGFP(-) cells purified at 24 hours after infection also generated a significant engraftment of CD45(+)/EGFP(+) and CD34(+)/EGFP(+) cells, suggesting that a number of transduced repopulating cells did not express the transgene at that time. Molecular analysis of NOD/SCID BM confirmed the high levels of engraftment of human transduced cells deduced from FACS analysis. Finally, the analysis of the provirus insertion sites by conventional Southern blotting indicated that the human hematopoiesis in the NOD/SCID BM was predominantly oligoclonal.

Comparative distribution of glutamyl and aspartyl aminopeptidase activities in mouse organs

To evaluate the functional role of glutamyl and aspartyl aminopeptidases, their soluble and membrane-bound activities were measured simultaneously in several tissues of normal mice using arylamide derivatives as substrates. Although the soluble aspartyl aminopeptidase activity showed its highest levels in the testicle, the rest of the activities presented their highest levels in the kidney. Different patterns of distribution were observed for glutamyl and aspartyl aminopeptidase activities and also for soluble and membrane-bound aspartyl aminopeptidase activities. However no major differences were observed between soluble and membrane-bound glutamyl aminopeptidase activities. This unequal distribution suggests that the use of arylamide derivatives as substrates is a sensitive method that distinguishes between these enzymatic activities. The results also suggest different functions for soluble and membrane-bound aspartyl aminopeptidase activities, and for glutamyl and aspartyl aminopeptidase activities.

[Toxigenic Vibrio cholerae non-01]

The antimicrobial susceptibility and the presence of a heat-stable toxin were researched into 100 non-01 Vibrio cholerae strains sent by 7 different health centers to the National Reference Laboratory of Acute Diarrheal Diseases in "Pedro Kourí" Tropical Medicine Institute. The presence of 20% toxigenic non-01 Vibrio cholerae was detected, a figure substantially higher than that reported in other geographic areas, except for endemic areas. This result will make it possible to set epidemiological alert in Cuba because these strains can be infected by CTX phages (element transporting genes that encode for choleric toxin) which will give such strains an epidemic potential similar to that of the etiologic agent of cholera. The identified strains could be studied as possible cholera vaccine candidates.

Influence of dietary supplementation with olive oil on pyroglutamyl-beta-naphthylamide hydrolysing activity in serum and different tissues of mice

Pyroglutamyl aminopeptidase is an omega peptidase which removes pyroglutamyl N-terminal residues from peptides and arylamide derivatives. To date, three distinct types of this enzyme have been described and called serum thyroliberinase, cytosolic pyroglutamyl aminopeptidase type I and membrane-bound pyroglutamyl aminopeptidase type II. The activity of all of them is thought to be involved in the regulation, more or less restricted in their substrate specificity, of various susceptible endogenous substrates such as TRH, GnRH, neurotensin, bombesin and anorexogenic peptide. It is well known that the type and amount of fat in the diet not only modify blood lipid concentrations, including cholesterol levels, but change the cell membrane lipid composition. Modifications in the composition and physical properties of the membrane lead to alterations in the activities of membrane-bound enzymes and carriers. The aim of this work was to compare the effect of a standard diet and a high fat diet (olive oil, 20% wt/wt) on pyroglutamyl-beta-naphthylamide hydrolysing activity, in serum and in soluble and membrane-bound fractions from different tissues of male mice. After ten weeks of feeding, pyroglutamyl-beta-naphthylamide hydrolysing activity was measured fluorometrically using pyroglutamyl-beta-naphthylamide as substrate. Mice fed the high fat diet had higher rates of body weight than controls starting from the second week of feeding. Serum total cholesterol concentrations were higher after feeding the high fat diet than after feeding the control diet. In serum, no changes were observed in the high fat group. In selected tissues, only pyroglutamyl-beta-naphthylamide hydrolysing activity was modified significantly in the soluble fraction, but not in the membrane-bound one, decreasing in the adrenal gland of high fat fed animals. The results may reflect functional modifications in susceptible endogenous substrates.

[Characteristics of Canavalia proteins]

The purpose of this work was the isolation and characterization of grain protein from five Venezuelan Genotypes (U-02, Yaracuy, Valle De La Pascua, Originally Tovar) of Jack Bean (Canavalia ensiformis). The average protein content from these genotypes was 31.37%, it ranged between 28.44% and 33.05%. The protein isolation was performed by solubility extraction procedures, showed: 84.57% of albumins, globulins and non proteic nitrogen and 15.43% of alcohol insoluble reduced glutelin (AIG). The content of anti-nutritional factors (canavanine and hemagglutination title) found in protein fractions were respectively: Albumins 1.96%, +4; globulins 0.17%, +5 and AIG 0.22%, +1. It was observed that protein fractions of genotype Tovar had the lowest canavanine values (0.79%, 0.02% and 0.00% respectively). The globulins gave the highest in vitro protein digestibility (65.20%) followed by Albumins (58.90%) and AIG (37.28%).

[In vitro study of the effect of ethanol on pyroglutamyl aminopeptidase activity in mouse synaptosomes under basal and stimulated conditions]

INTRODUCTION AND OBJECTIVE

Pyroglutamyl aminopeptidase (pGluAP) is an omega peptidase which removes pyroglutamyl N-terminals residues from peptides and arylamidase derivatives. This activity is thought to be involved in the regulation of several physiological mechanisms on the central nervous system. pGluAP can modulate various susceptible endogenous substrates such as thyrotrophin-releasing hormone (TRH). It is well known that TRH plays an important role in the modulation of the behavioral changes induced by ethanol and others drugs. The aim of this work was to study the in vitro effects of ethanol (25, 50 and 100 mM) on the pGluAP activity and its ability for modulating the TRH.

MATERIAL AND METHODS

pGluAP activity was measured in synaptosomes from cerebral cortex of mouse, using pyroglutamyl-beta-naphthylamide as substrate in basal and stimulated (K+ 25 mM) conditions, and in presence or absence of calcium on the buffer.

RESULTS

In basal conditions, ethanol produced an inhibition of the pGluAP activity in presence or absence of calcium, being this inhibition non dose-related. However, the stimulation with K+ 25 mM did not produce a modification of pGluAP activity in presence of calcium, but produced a light increase in absence of it. Depolarization in presence or absence of calcium and ethanol produced an inhibition of pGluAP activity, which changed in function of the ethanol concentration used.

CONCLUSIONS

Ethanol modifies pGluAP activity in basal conditions by a mechanism independent of calcium, but the changes observed after the stimulation with high K+ may be due to a calcium-dependent mechanism. These variations of pGluAP activity induced by ethanol, and their effects on their endogenous substrates, specially TRH, may be responsible for the behavioral changes associated to the alcoholism and mediated by TRH.

[Plesiomonas shigelloides, a Vibrionaceae to be taken into account]

The antigenic structure and antimicrobial susceptibility were studied in 99 strains isolated from patients with acute diarrhea (6 strains from an outbreak of digestive transmission disease in Santiago de Cuba) and a strain isolated from a patient who died from infections neurological syndrome (INS, meningitis). Four new serotypes (093, 994, 095, 096), which had not been described in the world classification, were identified from the Cuban isolated strains and were included in the International Serotyping Scheme by the International Reference Center located in Prague, Czech Republic. For the first time in Cuba, the circulation of serotypes 017:H11, 011: H2, 023. H1alc, 057: H3 which show cross reaction to Shiguella species was proved. Those strains from the outbreak of digestive disease belonged to serotype 050: H11 and had a thermostable toxin. The first case of infectious neurologic syndrome with Plesionomas shigelloides etiology reported in Cuba was described; the strain corresponded to serotype 050: H11. The worldwide reported pattern of antimicrobial resistance was demonstrated.