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Biomedical subjects

F Bertrand

Publications and source records attributed to F Bertrand.

At least 109 records · Page 6Linked to original sources
PubMed1979

Pentobarbitone effects on respiration related units; selective depression of bulbopontine reticular neurones.

Respiration related units (RRUs) were recorded in cats, locally anesthetized, vagotomized and immobilized, under two different experimental conditions: (1) receiving pentobarbitone intravenously at a dose inducing slight but highly significant changes in phrenic discharge; (2) unanesthetized, with a spinal section at C6. RRU characteristics were analysed in unitary volumes constituted by cubes of a matrix including the brain stem. Four parameters of RRU discharges were compared in cubes = RRU density (RRUD), RRU proportion and two indices of respiratory modulation. Cubes were sampled in: (1) dorsal and ventral bulbar respiratory nuclei, (2) pneumotaxic centre (PC), and (3) seven fields of the bulbopontine and mesencephalic reticular formation. Using the paired sample method for comparing data cube by cube in the two conditions it was shown that under pentobarbitone, RRU activity was profoundly depressed in the reticular formation surrounding dorsal and ventral bulbar respiratory nuclei, in the region bridging the gap between these and the pneumotaxic centre and extending from the pneumotaxic level to the decussation of the brachium conjunctivum. In contrast RRU activity was unchanged at the level of dorsal and ventral bulbar respiratory nuclei and in the nucleus parabrachiallis medialis (NPBM) and was increased in the Kölliker-Fuse nucleus (KF). In the mesencephalic reticular formation, increased activity was observed for non-modulated units and to a larger extent for units driven by the bulbopontine respiratory system.

Action Potentials↗
PubMed1979

Ascending projection from the respiratory centre to mesencephalon and diencephalon.

The brainstem reticular formation, subthalamus and thalamus were explored in a search for units modulated by the respiratory centre. Experiments were performed on cats under local anesthesia, in which respiratory center oscillation was independent of movement of the lungs and thorax. A large proportion of units firing tonically showed an increasing frequency, phase related to phrenic nerve activity. Respiration related units (RRUs) rostral to the pneumotaxic centre were concentrated in definite areas of the brainstem reticular formation, subthalamus and thalamus. Respiratory modulation disappeared rostral to a section performed at the ponto-mesencephalic junction.

Animals↗
PubMed1979

Changes in glycoproteins of liver plasma membranes from rats treated with D-galactosamine.

D-Galactosamine administration to rats (400 mg/kg) by intraperitoneal injection induced biochemical alterations in liver plasma membranes. Alterations were studied 4, 16 and 24 h after D-galactosamine injection. Plasma membrane 5'-mononucleotidase activity decreased to 40% of control values. Carbohydrate composition was significantly changed. After 24 h D-galactosamine administration, the diminution in plasma membrane sialic acids and hexoses reached 30% of control values. As detected by SDS-acrylamide gel electrophoresis, high molecular weight glycoproteins of D-galactosamine-treated plasma membranes were modified. Moreover, the incorporation of [35S]-sulfate into membrane glycoproteins decreased after D-galactosamine administration (40--60% of control). The present results show that biochemical alterations in rat liver plasma membranes appear soon after D-galactosamine injection. Marked changes are observed in cell surface glycoproteins, especially in sialoglycoproteins and sulfated glycoproteins.

Animals↗
PubMed1978

[beta2-Microglobulin and monoclonal gammapathies (author's transl)].

145 Determinations of beta2-microglobulin (beta2m) have been realized in 111 patients with a monoclonal gammapathy. The level of beta2m is significantly higher (p = 0,0001) in the group with monoclonal gammapathy (M = 4,75 mg/l +/- 5,62) than in normal subjects (M 1,38 mg/l +/- 0,38). In a group with monoclonal gammapathy with renal failure, the level of beta2m is higher (M = 7,07 mg/l +/- 7,76) than in a group with renal failure alone (M = 3,45 mg/l +/- 1,91). The difference is significant (p = 0,005). The level of beta2m is higher in IgA monoclonal gammapathies (M = 5,61 mg/l) than in IgG (M = 4,18 mg/l) or IgM (M = 4,37 mg/l) gammapathies, but the differences of the means between the three groups are not significant. The assay of beta-2m does not allow to distinguish myeloma (M = 3,18 mg/l +/- 1,83) from benign monoclonal gammapathy (M = 3,22 mg/l +/- 1,32) and is not useful when the diagnosis is difficult.

Beta-Globulins↗
PubMed1977

[Gamma heavy chain disease associated with rheumatoid arthritis. Spontaneous disappearance of the pathologic protein].

The authors report the chance discovery in a man aged 53 years with serum positive rheumatoid arthritis, of gamma 3 heavy chain disease. The originality of this case depended on the absence of any detectable lymphoid proliferation and on the transient character of the pathological protein. Only the course after a long follow up will determine whether there is no incipient lymphoid proliferation and whether the heavy chain disease has disappeared permanently.

Arthritis, Rheumatoid↗
PubMed1976

Discharge patterns of bulbo-pontine respiratory unit populations in cat.

Respiration related units (RRU) were recorded during a stratigraphic exploration of medulla and pons from the cervical junction to the caudal part of the pneumotaxic system in the semi-chronic locally anesthetized 'isolated respiratory centre' of the cat. Metal 'low impedance, capacitance compensated' microelectrodes recorded multi-unit signals from which unitary discharges were discriminated and processed by computer; it is suggested that using these techniques, the sample was a good representation of the total unit population. The phase relation to phrenic discharge was determined on cycle triggered time histograms. Of 23,000 units, 28% had a definite respiratory modulation. Examined individually, each RRU showed a stable discharge pattern corresponding to one of various respiratory types, the majority of which have been described previously. Both temporal and spatial distributions of RRU discharges were analyzed. Temporal distribution of peak firing frequencies (PFF) of 5,000 RRU sampled anatomically at random showed two main populations whose modes were observed during inspiration (I) or expiration (E). Troughs were observed in the histogram at the transition from I to E and E to I, thus indicating low probability for finding phase spanning RRU in the medulla and pons up to the pneumotaxic level. These statistical results turned out to be identical to those obtained with an a priori classification method comparable to that used in most of the previous works. In addition, the PFF distribution suggested that the E population could be further divided into 3 sub-populations whose modes fall in early, mid, and late expiration respectively. Comparison of RRU temporal distribution in two regions, one rostral, another caudal to a frontal Horsley-Clarke plane situated 3 mm in front of the obex, showed that, in the caudal region, 70% of the RRU were I units, while, in the rostral medulla and pons, equal proportions of I and E neurons were found. Temporal distribution of RRU peak frequencies was studied separately in anatomical structures where the probability of finding RRU was high. No clear correspondence between RRU types and anatomy could be found, but marked differences between structures were observed, thus suggesting nevertheless a different spatial distribution for I and E populations.

Animals↗
PubMed1976

Three dimensional representation of bulbo-pontine respiratory networks architecture from unit density maps.

Results of the preceding paper32 suggest that bulbo-pontine respiration related units (RRU) could be classed into 4 populations according to the relation of their peak firing frequency to the respiratory cycle: one inspiratory (I) and 3 expiratory (E) (early, mid and late). A further study of their spatial distribution is reported. Recorded units totalling 26,520 were distributed through a matrix of unitary cubes of which about 2,000 were found within the limits of the medulla and pons. Both percentage and density of respiratory and non-respiratory units were estimated in each cube. Statistical analysis of unit distribution showed a high probability of finding RRU in certain regions. The probability of finding I and E units in separate cubes was high, whereas there was no probability better than chance for recording one of the 3 E types separately from the 2 others. Therefore, only two populations, I and E, could be considered for spatial analysis. A thresholding technique applied to I and E unit density figures in unitary cubes demonstrated a definite limit for I and E populations. A computerized, three-dimensional (3-D) reconstruction of the outer surfaces of the I and E networks showed that half a medullary system consisted of 2 contiguous and uninterrupted columns extending from the cervical junction up to the pneumotaxic system. The main body of the I population was found in the caudal third and dorsolateral part of the bulbopontine region, while the main body of the E population was in the middle third in a ventromedial position. Both have caudal and rostral extensions that run parallel to the main axis of the brainstem and give rise to several lateral branches; these lie in close contact and interdigitate extensively, especially in the rostral third of the bulbopontine region. From the outer limits of I and E networks, a progressive increase of unit density levels was observed towards the core; it showed that inside both I and E populations, RRU aggregate into high density foci (HDF). Large HDF were found in the main body of each population. Smaller HDF were observed scattered throughout the medulla; I, and to a lesser extent E, HDF invade and surround sensory and motor nuclei and roots of the branchial nerves.

Animals↗
PubMed1975

A short-term memory in the respiratory centres: statistical analysis.

It has been observed previously that the successive values of depth and duration of respiratory cycles recorded in man are not independent random variable. The present study has been performed in order to test whether a serial dependence of the characteristics of the respiratory cycles results from an inherent property of the central respiratory oscillator. In the "isolated respiratory centre" preparation of the cat (spinalized, bivagotomized, curarized and artificially ventilated) the following respiratory data have been studied: the value of integrated phrenic discharge per breath (S), inspiratory duration (TI), expiratory duration (TE) and total cycle duration (T), at rest and during hypercapnia and hyperthermia. Each recording in a steady-state condition provided a set of four series of data; using statistical analysis of time series the following results were obtained: 1. In each series the successive values are not independent random variables. This suggests that a cycle may be considered as an event whose characteristics condition those of the following cycle. 2. TE is not independent of the preceding TI, and TI is not independent of the immediately preceding TE. However, this last relation cannot be asserted in hypercapnia and hyperthermia. 3. A positive correlation exists between S and TI. This result indicates that a simultaneous adjustment of S and TI, in terms of one another, does exist in absence of the vagal mechanism.

Animals↗
PubMed1975

Respiratory effects of pneumotaxic center lesions and subsequent vagotomy in chronic cats.

Ventilation was monitored in awake and anesthetized cats breathing air or CO2 mixtures, both before and after lesions in the pneumotaxic center region and after subsequent bilateral vagotomy. Cats with pontile lesions had, relative to intact state, a prolonged inspiratory duration and an increase in tidal volume and expiration duration. The changes seen on the spirogram differed quantitatively according to the region of the pneumotaxic system which was destroyed. After subsequent bilateral vagotomy, respiratory phases and tidal volume were greatly increased. These results indicate that the pneumotaxic center would control the sensitivity of Breuer-Hering reflex and that the inspiratory activity is released by the successive suppression of the two inspiratory-inhibitory mechanisms, i.e., the pneumotaxic center and the vagal pulmonary afferents.

Animals↗
PubMed1973

Organization of the pneumotaxic oscillator in the cat.

The present series concerns the topographical organization of pneumotaxic neurons within the nucleus parabrachialis medialis and adjacent structures according to their respiratory subtype. Results presented were obtained from 1000 units recorded in a region 2.5 mm in height, 1.5 mm in width and 2.5 mm in length. During penetration in the postero-lateral part (mainly in Kolliker-Fuse nucleus) inspiration related cells were found almost exclusively. Phase-spanning inspiratory-expiratory neurons largely predominated in the central core of nucleus parabrachialis medialis. A large majority of expiratory cells was recorded at the antero-medial border of the nucleus. In the intervening regions, clusters of 6 to 10 cells of the inspiratory-expiratory (IE) type alternated with similar clusters of either inspiratory- or expiratory neurons. Phase-spanning expiratory-inspiratory (EI) neurons were mainly found in the intermediary positions between phase-spanning IE and either inspiratory or expiratory columns. A two dimensional reconstruction of pneumotaxic organization is presented and a tentative model of the oscillator is advanced.

Animals↗