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Biomedical subjects

A Monnier

Publications and source records attributed to A Monnier.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Pattern formation and rhythm generation in the ventral respiratory group.

1. There is increasing evidence that the kernel of the rhythm-generating circuitry for breathing is located within a discrete subregion of a column of respiratory neurons within the ventrolateral medulla referred to as the ventral respiratory group (VRG). It is less clear how this rhythm is transformed into the precise patterns appearing on the varied motor outflows. 2. Two different approaches were used to test whether subregions of the VRG have distinct roles in rhythm or pattern generation. In one, clusters of VRG neurons were activated or inactivated by pressure injection of small volumes of neuroactive agents to activate or inactivate groups of respiratory neurons and the resulting effects on respiratory rhythm and pattern were determined. The underlying assumption was that if rhythm and pattern are generated by neurons in different VRG subregions, then we should be able to identify regions where activation of neurons predominantly alters rhythm with little effect on pattern and other regions where pattern is altered with little effect on rhythm. 3. Based on the pattern of phrenic nerve responses to injection of an excitatory amino acid (DL-homocysteate), the VRG was divided into four subdivisions arranged along the rostrocaudal axis. Injections into the three rostral regions elicited changes in both respiratory rhythm and pattern. From rostral to caudal the regions included: (i) a rostral bradypnoea region, roughly associated with the Bötzinger complex; (ii) a dysrhythmia/tachypnoea area, roughly associated with the pre-Bötzinger complex (PBC); (iii) a second caudal bradypnoea area; and, most caudally, (iv) a region from which no detectable change in respiratory motor output was elicited. 4. In a second approach, the effect of unilateral lesions of one subregion, the PBC, on the Breuer-Hering reflex changes in rhythm were determined. Activation of this reflex by lung inflation shortens inspiration and lengthens expiration (TE). 5. Unilateral lesions in the PBC attenuated the reflex lengthening of TE, but did not change baseline respiratory rhythm. 6. These findings are consistent with the concept that the VRG is not functionally homogenous, but consists of rostrocaudally arranged subregions. Neurons within the so-called PBC appear to have a dominant role in rhythm generation. Nevertheless, neurons within other subregions contribute to both rhythm and pattern generation. Thus, at least at an anatomical level resolvable by pressure injection, there appears to be a significant overlap in the circuitry generating respiratory rhythm and pattern.

Animals↗
PubMedDate not supplied

[Pulmonary thromboembolic diseases in Ivory Coast (apropos of 13 cases)].

From January 1983 to March 1984, 13 cases of pulmonary thrombo-embolic disease (PTE) were reported at the Abidjan cardiology Institute. Disease frequency is higher than usually reported in Africa. The reason is that angiography was carried out as soon as the clinical diagnosis was suspected. Radiologic examination allowed to locate with accuracy the level of the thrombosis. Under heparin, a favourable course of the disease was noted any time a phlebitis of lower extremity was involved. Two deaths occurred among the 13 cases. Few differences are noted in Africa and temperate zones as regard to disease behaviour. However, frequency of obstetrical and infectious aetiology is to be outlined.

Adult↗
PubMedDate not supplied

[Acute disseminated lupus erythematosus in Ivory Coast (apropos of 9 cases)].

Nine cases of systemic lupus erythematosus (S.L.E.) among ivoirian Africans seen over a period of eleven years were studied. The pattern of clinical presentations is similar of that seen elsewhere. Photo-sensitivity is not described as in american Negroes. Death is usually due to severe infection. The incidence of the disease among populations of different african countries are compared. The low prevalence 0,18 p. mille may be a function of failure to diagnose the more mild cases.

Acute Disease↗