Biomedical subjects

A Brancati

Publications and source records attributed to A Brancati.

At least 19 recordsLinked to original sources

PubMed1999

Effects of weight loss on body composition and pulmonary function.

BACKGROUND: The relationship between obesity, impaired respiratory function and weight loss is established. OBJECTIVE: Some aspects need further elucidation: the different impact of the pathological modifications of body compartments (total and regional fat mass and lean body mass) on respiratory function, the choice of a restricted diet, the relationship between the modifications of body compartments and the variations in respiratory parameters after weight loss. METHODS: The restricted diet was elaborated according to the traditional Mediterranean diet. In a series of 16 obese patients, respiratory function was assessed by spirometry; body composition was assessed by dual-energy X-ray absorptiometry, allowing the direct estimation of total and segmental body fat and lean body mass. RESULTS: Weight loss was sustained mainly by fat mass decrease, mostly upper body fat. Total and truncal lean body mass were not affected. Lung volumes and function were improved. A correlation was observed between lean body mass and respiratory parameters, and was unmodified after weight loss. CONCLUSIONS: Mediterranean-style restricted diet was well accepted and enabled a selective decrease in fat mass, with a good improvement in lung function. Truncal fat (as well as abdominal fat) was decreased, while truncal lean body mass (i.e. respiratory muscles) were not affected, as expected in obese subjects with respiration problems.

Absorptiometry, Photon↗

PubMed1999

A new predictive equation to calculate resting metabolic rate in athletes.

BACKGROUND: The purposes of the present study were: 1) to examine the accuracy and precision of seven published equations for predicting resting metabolic rate (RMR) in male athletes and 2) to develop a population-specific equation. SETTING: The study occurred during a non-intensive training period. The measurements were performed at the Human Physiology laboratory. PARTICIPANTS: Fifty-one male athletes (22 waterpolo, 12 judo, 17 karate) who exercised regularly at least three hours per day. MEASURES: RMR was measured (mRMR) using indirect calorimetry (ventilated hood system). Besides, mRMR was compared with values predicted (pRMR) using equations of FAO/WHO/UNU, Harris and Benedict, Mifflin et al., Owen et al., Cunningham, Robertson and Reid, Fleisch. Statistical analyses. mRMR was compared with pRMR by means of Student's paired "t" tests, linear regression analysis and the Bland-Altman test. Relationships between mRMR and the different predictive variables were evaluated by Pearson correlation coefficients. The best subset was used to develop the predictive equation for RMR. RESULTS: mRMR was significantly underestimated by six of the seven equations in this sample of athletes. Only the Cunningham equation overestimated (+59 kcal/d) the actual RMR. Bland-Altman 95% limits of agreement were wide (+/- 200-300 kcal/d) for all equations. RMR correlated best with body surface area (r = 0.88), body weight (r = 0.84) and height (r = 0.81). The best-fit equation for the entire data included both weight and height and it was given by: RMR (kcal/d) = -857 + 9.0 (Wt in kg) + 11.7 (Ht in cm) (R2 = 0.78; SEE = 91 kcal/d; 95% IC: -226, 228). CONCLUSIONS: For an individual resting metabolic rate evaluation, the use of indirect calorimetry is recommended. In conditions where this technique cannot be used, our developed equation can predict the RMR of athletes better than any of the currently available prediction equations.

Adult↗

PubMed1996

Marked decrease of plasma neuroactive steroids during alcohol withdrawal.

The neuroactive steroids allopregnanolone (ALLO) and allotet-rahydrodeoxycorticosterone (THDOC) are the most potent endogens positive modulators of gamma-aminobutyric acid (GABA) on GABAA receptors, a receptor system presumably responsible for some behavioral responses to alcohol withdrawal. In a group of nine alcoholic subjects, the levels of plasma ALLO and THDOC were markedly lower than those of control subjects during the early withdrawal phase (day 4 and 5), when anxiety and depression scores were higher. In contrast ALLO and THDOC plasma levels did not differ from those of control subjects during the late withdrawal phase when anxiety and depression scores were low. These results suggest that the decrease of neuroactive steroid biosynthesis may contribute to the withdrawal symptoms.

Adult↗

PubMed1994

Age-dependent appearance of synaptic currents in rat neocortical neurons in culture.

Rat neocortical neurons grown in dissociated cell culture were recorded with the whole-cell patch-clamp technique. Spontaneous inward currents were observed in cells that were held at a membrane potential of -80 mV in medium containing tetrodotoxin and Cd2+. These currents displayed amplitudes up to 140 pA and rise time of 1.8 +/- 0.2 ms (mean +/- SD, n = 15). They reversed near 0 mV and showed no voltage-dependent frequency of occurrence. Hence, they were presumably due to spontaneous release of transmitter. The inward currents appeared around day 10 in culture and were detected up to 4 weeks. When cells of different ages were compared, the maximal probability of recording these inward events occurred at around 3 weeks in culture. The inward currents were not reduced by application of bicuculline methiodide which is a competitive antagonist of the GABAA receptor, but were blocked by the broad-spectrum glutamate receptor antagonist kynurenic acid. Moreover, spontaneous inward events were not affected by DL-2-aminophosphono-valerate (NMDA receptor antagonist) but disappeared following application of the non-NMDA receptors antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Our observations indicate that the inward currents represent miniature synaptic events that are primarily mediated by non-NMDA excitatory amino acid receptor subtypes. Furthermore, our findings indicate that they develop over time and are not present in neurons that are grown in culture for less than 10 days.

2-Amino-5-phosphonovalerate↗

PubMed1993

Sodium, calcium and late potassium currents are reduced in cerebellar granule cells cultured in the presence of a protein complex conferring resistance to excitatory amino acids.

Whole-cell, patch-clamp recordings were used to study voltage-gated currents generated by cerebellar granule cells that were cultured in medium containing either 10% fetal calf serum (hereafter termed S + granules) or neurite outgrowth and adhesion complex (NOAC, hereafter called NOAC granules). NOAC is a protein complex found in rabbit serum that renders granules resistant to the excitotoxic action of excitatory amino acids. During depolarizing commands both S+ and NOAC granules generated Na+ and Ca2+ inward currents and an early and a late K+ outward currents. However, Na+ and Ca2+ inward currents and late outward K+ currents recorded in NOAC granules were smaller than those seen in S+ granules. Furthermore, although of similar amplitude, early K+ currents displayed different kinetics in the two types of neurons. Thus, these data demonstrate that the electrophysiological properties of cerebellar granules, and probably of other neuronal populations, depend upon serum components and raise the possibility that an analogous modulation might be operative in vivo, and play a role in development, synaptic plasticity or neuropathological processes.

4-Aminopyridine↗

PubMed1991

Effects evoked by pentamethylenetetrazol-induced seizures upon N-acetylaspartate and N-acetylaspartylglutamate levels in different regions of the rat neuraxis.

We have examined the effects evoked by pentamethylenetetrazol (PTZ)-induced seizures upon the concentration of N-acetylaspartate (NAA) and of N-acetylaspartylglutamate (NAAG) in the forebrain, brainstem and spinal cord of rats. We observed a significant decrease of both NAA and NAAG in each one of the studied regions. These findings are consistent with an inhibitory role proposed in CNS for NAA and NAAG.

Animals↗

PubMed1990

Distribution of N-acetylaspartate, N-acetylaspartylglutamate, free glutamate and aspartate following complete mesencephalic transection in rat neuraxis.

The distribution of N-acetylaspartate (NAA), N-acetylaspartylglutamate (NAAG), free glutamate (Glu) and aspartate (Asp) was studied in the neuraxis of rats 48 h after complete transection of brain stem at the intercollicular level. NAA remained unchanged above the transection level but decreased in the neur-axis segments caudal to the lesion. Glu was strongly depressed both in the segments rostral to the transection and in the ones caudal to it. No significant change was found for NAAG and Asp. These findings are consistent with the hypothesis that NAA may be involved in neurotransmission processes and provide further evidence for Glu as transmitter of descending and ascending pathways. In addition, the data obtained do not suggest a direct metabolic or functional relationship between NAA and NAAG nor between these N-acetylderivatives and free Glu and Asp.

Animals↗

PubMed1990

Low magnesium epileptogenesis in the rat hippocampal slice: electrophysiological and pharmacological features.

Extra- and intracellular recording techniques were used to study the epileptiform activity generated by rat hippocampal slices perfused with Mg2(+)-free artificial cerebrospinal fluid (ACSF). This procedure induced in both CA1 and CA3 subfields the appearance of synchronous, spontaneously occurring epileptiform discharges which consisted of extracellularly recorded 100-800 ms long, positive shifts with superimposed negative going population spikes. Simultaneous, extracellular recordings from CA1 and CA3 subfields revealed that the epileptiform discharges in CA3 preceded those occurring in CA1 by 5-25 ms. Surgical separation of the two areas led to the disappearance of spontaneous events in the CA1 but not in the CA3 subfield. In this type of experiment CA1 pyramidal cells still generated epileptiform discharges following orthodromic stimuli. The intracellular counterpart of both spontaneous and stimulus-induced epileptiform discharges in CA1 and CA3 pyramidal cells was a large amplitude depolarization with high frequency discharge of action potentials which closely resembled the paroxysmal depolarizing shift recorded in the experimental epileptogenic focus. A hyperpolarizing potential triggered by alvear stimuli was recorded in CA1 cells perfused with Mg2(+)-free ACSF. This hyperpolarization was blocked by bicuculline methiodide (BMI) indicating that it represented a GABAergic inhibitory postsynaptic potential (IPSP). BMI also caused a prolongation of both spontaneous and stimulus-induced Mg(+)-free epileptiform discharges. Perfusion of the slices with the N-methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-5-phosphono-valerate (APV) reduced and eventually abolished the Mg(+)-free epileptiform discharges. These effects were more pronounced in the CA1 than in the CA3 subfield. APV also reduced the amplitude and the duration of the alveus-induced IPSP. These data demonstrate that Mg(+)-free epileptiform activity is present in the hippocampal slice at a time when inhibitory GABAergic potentials are operant as well as that in the CA1 subfield this type of epileptiform activity is dependent upon NMDA-activated conductances. Our experiments also indicate that NMDA receptors might be involved in the neuronal circuit responsible for the hyperpolarizing IPSP generated by CA1 pyramidal neurons.

2-Amino-5-phosphonovalerate↗

PubMed1983

Interactions between amino acid neurotransmitters and flurazepam in the neocortex of unanesthetized rats.

The effects induced by the benzodiazepine flurazepam (FLU) upon neuronal responses to glutamic acid (GLUT), gamma-aminobutyric acid (GABA), and glycine (GLY) were studied in the cortex of unanesthetized rats using single-unit extracellular recordings in conjunction with iontophoretic techniques. The application of FLU (5-20 nA) did not affect excitatory responses to GLUT, but the spontaneous firing rate was depressed by equivalent doses of this benzodiazepine. A selective increase of GABA, but not of GLY-induced responses was seen when either low currents (5-10 nA) of FLU or GLUT driving currents were used to study the neuronal responses of the inhibitory amino acids upon steady neuronal firing. Our data demonstrate that in unanesthetized animals FLU does not affect GLUT-induced effects while it selectively increases GABA-mediated inhibition.

Amino Acids↗

PubMed1982

[Effect of acute intravenous administration of thyroliberin on circulating reverse-T3].

Some of the Authors previously demonstrated a significant precocious serum T3 increase after 200 micrograms TRH acute intravenous administration (TRH test). Reverse-T3 (rT3) is now known to interfere with T4 conversion to T3. We therefore compared spontaneously occurring to TRH test-induced changes in T3 and rT3 serum levels within a group of four healthy women in fertile age. Maximum rT3 increase during TRH test did not differ significantly from the maximum spontaneous variation at the same time of the day. Maximum T3 increase, on the contrary, was significantly higher than observed maximum spontaneous variation (0,81 ng/ml versus 0,39 ng/ml increase, p less than 0,01). Possible implications are discussed in the text.

Adolescent↗

PubMed1982

[Comparison between spontaneous changes in circulating triiodothyronine (T3 and reverse-T3) and those induced by acute intravenous administration of thyroliberin].

Some of the Authors had previously observed a slight-non significant decrease in T3 serum levels 10 minutes after TRH intravenous administration. On the other hand, it is now well known that reverse T3 (rT3) inhibits T4 conversion to T3. We therefore investigated the changes in T3 and rT3 serum levels within the first ten minutes of a 200 micrograms TRH test in a group of 10 healthy women in fertile age. No significant change in T3 was demonstrated. On the other hand, rT3 showed a significant-yet slight-decrease 6 minutes after TRH injection (from 0,27 to 0,21 ng/ml, p less than 0,05). Some feasible explanations for this phenomenon are given in the text.

Adolescent↗

PubMed1982

Neuronal responses to putative neurotransmitters during penicillin epileptogenesis.

An epileptogenic process was induced within the rat frontoparietal cortex by microiontophoretic applications of penicillin. The temporal development of the penicillin-induced activity was divided into (a) a first phase characterized by an increased rate of neuronal firing, (b) a pre-paroxysmal phase wherein neurons began to fire clusters of action potentials and (c) a paroxysmal phase characterized by a discharge of action potential clusters. The excitatory responses to glutamate and to acetylcholine appeared to be enhanced during the first and pre-paroxysmal phases, whereas a loss of the excitatory effectiveness of both glutamate and acetylcholine occurred during the final paroxysmal phase. Forty nine of 69 neurons studied (71%) showed a decreased sensitivity to gamma-aminobutyrate during the first phase of penicillin iontophoresis. However, during this same time, glycine-induced inhibition was not decreased. During the second phase, gamma-aminobutyrate-induced inhibition was even less effective, and glycine started to lose effectiveness. During the third phase, both these inhibitory neurotransmitters failed to affect the neuronal activity. The other 29% of the neurons studied showed a general diminution to the actions of both gamma-aminobutyrate and glycine when penicillin-induced action potential clusters appeared. Our results suggest that penicillin interferes with gamma-aminobutyrate-mediated inhibition in a large proportion of cortical neurons of the rat. Furthermore, these cortical neurons show changes in the responses to both excitatory and inhibitory neurotransmitters that closely parallel the development of penicillin-induced activity.

Action Potentials↗

PubMed1981