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Biomedical subjects

F Mora

Publications and source records attributed to F Mora.

At least 91 records · Page 5Linked to original sources
PubMed1994

Unchanged exocytotic release of glutamic acid in cortex and neostriatum of the rat during aging.

The Ca(2+)-dependent release of glutamate induced by 4-aminopyridine in synaptosomes prepared both from the cerebral cortex and basal ganglia was unchanged in aged rats (27-30 months) when compared to adults rats (3 months). Consistent with the absence of changes in glutamate exocytosis during aging, the rise in the cytosolic free Ca2+ concentration, [Ca2+]c, induced by depolarization in synaptosomes from aged rats was similar to that found in control adult rats. The results suggest that during aging the nerve terminals from the cerebral cortex and basal ganglia maintain an intact ability to release glutamate by exocytosis.

4-Aminopyridine↗
PubMed1994

Fixed versus removable microdialysis probes for in vivo neurochemical analysis: implications for behavioral studies.

The levels of several neurochemicals, i.e., uric acid (UA), dopamine (DA), dihydroxyphenylacetic acid, and 5-hydroxyindoleacetic acid, collected daily from the rat striatum with either fixed or removable microdialysis probes for 7 days after surgery were compared. The implantation of the fixed cannula was followed by a 10-fold increase in the UA content in the dialysates collected from the first day after surgery onward and by a steady decrease in dihydroxyphenylacetic acid levels, whereas those of DA remained fairly stable. With the removable cannula system, only a smaller, transient increase in UA during the first 3 days after surgery was observed, with no change in DA or monoamine metabolites. The glial reaction around the cannula tracks was assessed by both quantitative histological techniques and measuring the glutamine levels in the dialysates collected at the time of surgery and 7 days later. Both the glial cell number and nuclear size, as well as the glutamine outflow, were considerably larger in the animals implanted with the fixed probes. It is, therefore, likely that the UA levels in the dialysate reflect the glial reaction to the probe. The suitability of the removable probe system for behavioral experiments involving repeated microdialysis sampling was illustrated in an experiment showing that the DA release in the nucleus accumbens of male rats assessed daily at postsurgery days 5-10 was virtually identical in three alternating sessions of sexual behavior as was the smaller release of this neurotransmitter detected during intervening nonsexual social interactions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

Effects of neurotensin on the release of glutamic acid in the prefrontal cortex and striatum of the rat.

The effects of neurotensin (NT) on the extracellular concentrations of excitatory amino acids (EAA) glutamic acid (GLU) and aspartic acid (ASP) in the medial prefrontal cortex (MPC) and striatum (ST) of the conscious rat have been studied. NT was infused directly into these two structures for 10 min at doses of 10, 100 and 1000 nM. In the MPC, NT produced a dose-related increase of GLU. Also, NT produced a delayed increase of ASP at the highest dose. In ST, NT at doses of 10, 100 and 1000 nM produced no effect on GLU and ASP. It is suggested that the increase of GLU and ASP in the MPC could be due to a direct effect of NT on pyramidal cortical neurones. On the contrary, it is suggested that a direct interaction NT-GLU does not exist in the ST of the rat.

Animals↗
PubMed1993

Amphetamine-induced release of diadenosine polyphosphates--Ap4A and Ap5A--from caudate putamen of conscious rat.

The release of diadenosine polyphosphates--diadenosine tetraphosphate (Ap4A) and diadenosine pentaphosphate (Ap5A)--was measured by intracerebral push-pull perfusion in conscious rats after systemic amphetamine injection. Samples were collected from the caudate putamen, and nucleotide compounds were analyzed by HPLC. The presence of Ap4A and Ap5A was demonstrated by their retention times and phosphodiesterase digestion. Dinucleotides were not detectable before amphetamine injection (5 mg/kg). The maximal levels were reached 20 min after the injection with values of 12.9 +/- 0.9 and 11.5 +/- 0.9 pmol/fraction for Ap4A and Ap5A, respectively. A slow and progressive decrease in their concentration followed. This study shows for the first time the amphetamine-induced release of diadenosine polyphosphates in conscious rats, and a role for Ap4A and Ap5A in the central nervous system is therefore suggested.

Adenine Nucleotides↗
PubMed1993

Dopamine receptor antagonist blocks the release of glycine, GABA, and taurine produced by amphetamine.

The effects of systemic injections of amphetamine sulfate on the extracellular levels of glycine, GABA, and taurine in the neostriatum of awake rats were studied using a push-pull perfusion system. Amphetamine produced a dose-related increase in glycine levels. Amphetamine also produced an enhancement on GABA and taurine levels, although these increases did not follow a dose-related curve. The percentage increase of amino acids produced by the highest dose of amphetamine (5 mg/kg) at the peak effect was: GLY 235.9%; GABA 218%, and TAU 177%. All these effects were blocked by the D1-D2 dopamine receptor antagonist, haloperidol. It is suggested that dopamine, released by amphetamine, induces the release of inhibitory amino acid neurotransmitters in the neostriatum. These results are consistent with the hypothesis of dopamine playing a role of an amplifier of the activity of different neurochemical circuits. The results are also in accord with the idea that dopamine could mediate the neurotoxic effects produced by amphetamines through an interplay between excitatory and inhibitory amino acids.

Amphetamine↗
PubMed1993

[Value of long-term ambulatory pH-metry in the assessment of patients with reflux esophagitis].

The aim of this study is to analyze different reflux-patterns by 24-hour ambulatory pH-metry and to correlate them with clinical symptoms and intensity of esophagitis. 115 patients (50 males/65 females) with a median age of 47 +/- 16 years, typical reflux symptoms have been studied and classified attending to the grade of esophagitis microscopically only 17 cases and endoscopically (grade I = 29, grade II = 44 and grade III/IV = 25 patients). Demeester's score has been used for clinical evaluation. Ambulatory pH-metry has been done with a Holter Synectics Digitrapper MK II, which registered intraesophageal pH-variations every 4 seconds during 24 hours. 28 normal subjects (13 males/15 females) with a median age of 51 +/- 16 years are referred as the control group. Clinical symptoms became more intensified when pH-metric alterations resulted more evident. Thoracic pain was noted in 12 from 115 patients, increasing its frequency in parallel fashion to that of the degree of esophagitis (6% in grade 0, 9% in grades I/II and 20% in grades II/IV). With increasing grades of esophagitis all parameters departed from normality, with significant differences between median values of the different parameters (to the exception of reflux episodes) when comparing patients with low-grade esophagitis (O/I) and high-grade esophagitis (II/III/IV). There is an excellent correlation between severity of esophagitis and % of time to acid exposure (Spearman's correlation coefficient). Only 5% of the patients with esophagitis presented normal pH-metry values and corresponded to esophagitis grade O/I. No patient had only a night reflux pattern, but 10% of our patients had only a day reflux pattern, the mixed pattern being the most frequent one (85%). The fact that 82% of our patients with microscopical esophagitis had a pathological pH-metry recommends the use this method in patients with clinical reflux symptoms and with normal endoscopy.

Adult↗
PubMed1993

[Metoclopramide versus cinitapride in the treatment of functional dyspepsia].

In 20 patients with diagnosis of functional dyspepsia due to dysmotility and/or reflux, the effectivity and tolerance of two prokinetic drugs--metochlopramide (MCP) (10 mg. three daily doses, vo) and cinitrapide (CTP) (1 mg., 3 daily doses, vo)--were assessed using a protocol of a propective and cross-sectional study after a blank period. Following the treatment with MCP and CTP, statistically significant improvements were observed in the intensity/severity of postprandial epigastric fullness, flatulence, epigastralgia, pyrosis, active regurgitations and anorexia. The MCP was more effective for the improvement of vomiting in these patients; however, the number of defecations per week increased significantly only after the CTP therapy. The therapeutical effectivity of both drugs, according to a subjective and objective global assessment was similar, with good results of 60-65% for MCP and 55-60% for CTP. Tolerance of both drugs was good. None of the patients spontaneously referred to the presence of side effects and only 3 patients (15%) treated with MCP and 2 patients (10%) treated with CTP mentioned some of the suggested side effects, which were absent before the onset of treatment. Both drugs produced an increase in the levels of Prolactine, but their average values were within the normal range. Only in two patients treated with MCP and in one patient treated with CTP, values slightly higher than the upper normal limit were observed. No significant differences were observed when comparing the results obtained with MCP therapy and CTP therapy.

Adult↗
PubMed1992

[Colonic transit time (segmental and total) in healthy subjects and patients with chronic idiopathic constipation].

BACKGROUND: The efficacy of the treatment of patients with chronic idiopathic constipation not responding to normal therapeutic measures depends on correct functional diagnosis. The study of the segmentary and total colonic transit time with radioopaque markers is the most economic technique in everyday clinic ambience for functionally evaluating these patients. METHODS: Segmental and total colonic transit time was calculated with the use of radioopaque markers in 23 healthy subjects (12 men and 11 women) and in 13 women with severe idiopathic constipation. Twenty markers were administered daily for three consecutive days and simple x-rays of the abdomen were made on the fourth, seventh and in some cases on the tenth day. In addition, the symptomatology of 9 patients was collected by means of a 30 day diary. RESULTS: The maximum values of transit time (mean + 2SD) obtained in the healthy subjects were 17, 25, 26, and 49 hours for the right colon, left colon, rectosigmoid and the whole colon, respectively. The time of left colon transit was significantly lower in the women. The transit time in constipated patients permitted the differentiation of three functional patients: a) slowing of the right and left colon possibly associated to rectosigmoid slowing in 5 patients; b) isolated slowing in the left colon in 4 patients and c) isolated rectosigmoid slowing in 4 patients. Group a) was characterized by long total colonic transit times while these were normal in 2 patients of group b) and in one patient of group c). No differences were seen in the symptomatology of the groups. CONCLUSIONS: The calculation of segmentary and total colonic transit time with radioopaque markers is a simple technique which permits the detection of different subgroups of patients with chronic idiopathic constipation refractory to normal treatment. The exact typification of the functional anomaly is an important basis for the individualization of treatment.

Adult↗
PubMed1992

[Oropharyngeal functional assessment in patients with Zenker's diverticulum. Manometric and isotopic study].

Twenty patients with the diagnosis of Zenker's diverticulum were studied clinically and manometrically. In 8 patients oropharyngeal clearance of liquid isotopic markers was done. In three, esophageal emptying of a marked meal was also studied. Clinically, sixteen patients had oropharyngeal dysphagia, while for remained asymptomatic. Dysphagia was severe in only five patients. In half of the patients there were signs of hiatus hernia and/or reflux. Pharyngo-sphincteric incoordination was present in 70% of cases with a mean resting pressure of the LES significantly lower than in controls. There were no differences among patients with or without reflux. Isotopic esophageal clearance was not useful as a test, as there were no significant differences with the control group. On the other hand, esophageal emptying of solid isotopic meals may show the persistence of food in the diverticular sac long time after the meal.

Deglutition Disorders↗
PubMed1991

[Oropharyngeal dysphagia due to a primary change in the pharyngeal musculature. A manometric and isotopic study].

Twenty-five patients with oropharyngeal dysphagia due to a variety of disorders (4 with muscular dystrophy, 4 with myasthenia gravis and 13 with inflammatory myopathies) were studied clinically by esophageal manometry and isotopic clearance. Clinically patients had moderate dysphagia and 45% other symptoms such as nasal regurgitation, bronchial aspiration, etc. The most important manometric abnormality was the feeble contractions of the pharyngeal musculature, more pronounced in patients with severe dysphagia (grade II). Isotopic clearance of the oropharynx showed slowing of the pharyngeal emptying curve and an increased residual activity in this area. Isotopic oropharyngeal clearance is a useful, comfortable and noninvasive test for determining the clinical improvement which accompanies the manometric recovery of the pharyngeal muscular contraction.

Deglutition Disorders↗
PubMed1991

Chronic idiopathic constipation: the importance of transit time studies.

Chronic idiopathic constipation includes a very heterogeneous group of alterations which cannot be correctly defined only by their clinical appearance and require an examination of the colonic transit time. This test is performed by using a specific number of radiopaque markers and a fixed number of X-ray observations. By means of transit time study, we can classify the constipated patients into 4 groups: a) patients with stasis in the right colon (17-53% of cases) which implies an alteration of propulsive forces or absence of mass movements and segmentary motor activity; b) stasis in the left colon (13-27% of cases) which could be due to a "reflux" of colonic contents or to a hyperactive sigmoid; c) rectosigmoid stasis (20-33% of cases) which is secondary to a megarectum. Internal anal sphincter (IAS) and/or external anal sphincter (EAS) function failure and d) normal transit time (greater than 40 of cases) which is commonly due to psychological problems or to a low-fiber-content diet. We can conclude that transit time study is not necessary in mild constipation, but it is advised for those patients who do not respond to standard medical therapy or when surgery is being contemplated.

Anal Canal↗
PubMed1991

Alteration of recto-anal motility in chronic idiopathic constipation.

We studied anorectal function in 10 controls and 13 constipated patients (chronic idiopathic constipation, outlet obstruction and inertia coli). We did not find any difference among the 3 groups as regards the internal anal sphincter (IAS) basal tone, the recto-anal inhibitory reflex (RAIR) and the maximal voluntary contraction, whereas some significant differences were observed in the sensitivity threshold. In fact, we observed that all patient groups required larger volumes in order to perceive the minimum sensation. Moreover, the patients with distal obstruction showed higher threshold for a permanent defecation stimulus. The reduction of rectal sensitivity in these patients was confirmed by the infusion of 1500 cc of saline solution. On the basis of our experience constipated patients are characterized by both normal IAS tone, RAIR appearance, squeezing capacity, and lower rectal sensitivity.

Adult↗
PubMed1991

The irritable bowel syndrome: diagnostic strategies.

The irritable bowel syndrome (IBS) is characterized by abdominal pain, abdominal distension and altered bowel habits. The diagnosis is usually made by excluding other diseases. The diagnosis of IBS must be based on a) medical history (i.e. symptoms, bowel habits, normal physical examination, absence of intestinal infections or parasites) b) physiopathological evaluation (hyperactivity of the distal colon, hypersensitivity to stimuli, stress), and c) physiological evaluation of the patient. The diagnosis of IBS can be supposed in patients with typical symptoms in the absence of other diseases that were excluded by complementary examinations.

Abdominal Pain↗
PubMed1991

Colonic sensitive-motor alterations in the irritable bowel syndrome.

The pathogenetic factors involved in the genesis of the irritable bowel syndrome (IBS) has not been fully explained yet. The abnormalities observed in these patients are a hypersensitivity to distension and an amplification of painful sensations. The motor activity of sigmoid colon shows an increased motility index in IBS patients with constipation and a low motility index in those with diarrhea. An hypercaloric meal induces a hypermotility in these patients. In our experience rectal distension evokes abdominal pain in 78% of cases at volumes of 100ml (less than than controls and constipated patients). The perfusion of rectum induces continuous abdominal pain in 89% of IBS patients. We can say that the motility of the whole colon over prolonged periods of time may represent an important progress in understanding the motor function in these patients.

Abdominal Pain↗
PubMed1991

[Reoperations after esophagomyotomy in esophageal motility disorders].

Out of 96 patients with the diagnosis of primary esophageal motor disorders and treated by esophagomyotomy, a group of 9 patients is reported in whom reoperation was necessary because of persistence or worsening of the previous symptoms (8 patients) or persistent reflux esophagitis (one patient). Clinical and laboratory examinations together with the operative findings allowed classification of these patients: incomplete myotomy proximally (4 patients) or distally (one patient), fibrotic scar at the site of previous myotomy (2 patients), persistence of intact muscle fibers (one patient) and reflux esophagitis for lack of an antireflux intervention during myotomy. Treatment consisted of completing myotomy proximally or distally, resection of the fibrous tissue and an antireflux operation when indicated. Clinical results were excellent in 6 patients (66.6%), fair in 2 patients (22.2%) and bad in one case (11.1%). Fair or bad results were seen in patients with total absence of motor response to deglutition. After operation there was disappearance of vigorous contractions in the esophagus, as shown by manometry and recovery of esophageal peristalsis in another patient. We conclude that in order to improve the results of the surgical treatment of motor esophageal disorders it is essential to correctly classify the type of disorder present by means of manometry and to add a partial funduplication to ensure absence of reflux without dysphagia.

Adolescent↗