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Biomedical subjects

M Vincent

Publications and source records attributed to M Vincent.

At least 451 records · Page 25Linked to original sources
PubMedDate not supplied

[Acoustic emissions from the ear].

In this paper we study the phenomenon of the acoustic emissions. This study presents two cases with different auditif pathology and their clinics applications.

Acoustic Impedance Tests↗
PubMedDate not supplied

Eliminating interferences in a compendial test for oxidizable substances in water.

The United States Pharmacopoeia (USP) uses acidified potassium permanganate to test for dissolved organics in pharmaceutical-grade water. In the test, a standard permanganate concentration is added to a boiling, acidified water sample. Visually inspecting the sample for residual permanganate determines whether the sample passes (pink color remains) or fails (pink color disappears) the test. The permanganate redox chemistry is complex, however, and test samples are prone to developing suspended particulate and colors other than pink. Forming hazy or off-colored solutions interferes with the subjective end point determination according to the USP test. We report two alternative end point determinations that essentially eliminate interferences from the compendial test method. The first alternative involves recording a uv-visible spectrum of the reduced permanganate test solution. Residual permanganate shows three distinct absorbance maxima at 510, 526, and 545 nm. It is straightforward to differentiate the characteristic permanganate fingerprint from the broad, lower-wavelength extinction that results from interfering substances. The second alternative involves filtering the reduced permanganate test solution through sintered glass. This filtration step removes manganese oxides and other colloidal particles that contribute to haze and off color formation in test samples. Visually inspecting the filtrate for residual pink color remains the end point determination for the test method. A third alternative method, namely spectrophotometric determination of permanganate loss rate constants is not a suitable alternative owing to a strong dependence of permanganate reduction rate on organic substrate structure.

Filtration↗
PubMedDate not supplied

[Valium-Acupan combination--its value at an isolated health center].

Twelve anaesthesias of the diazo-analgesia type have been carried out using a combination of two non depressive analgesics: a narcotic one and a powerful central one. These interventions are classified; used technique is described and results are commented on. Indications are not too painful quick surgical acts performed on patients with an empty stomach.

Anesthetics↗
PubMedDate not supplied

[Loco-regional anesthesia in remote medical units. I. - Basis (author's transl)].

This paper is a foreword to a series of articles about anesthesia in small medical units in tropical areas. When general anesthesia must be discarded in regard to the patient's condition or the poor level of facilities, loco-regional anesthesia proves to be of great value. The authors review the main drugs available, their dosages, accidents, counter-indications and pre-anesthetic cares.

Anesthesia, Conduction↗
PubMedDate not supplied

[Shock during necrotic amoebic colitis (author's transl)].

Two varieties of conditions of shock may be isolated during necrotic amoebic colitis (13 cases). Eight patients present a simple hypovolemic shock secondary to wastage by diarrhea and perilesional oedema with globular, protein, alcaline and potassic deficiency. Its prognosis is relatively good, after vascular infilling and corrections of metabolic disorders. Five other patients present real toxi-infectious shock resulting from widespread tissue necrosis with auto-intoxication associated with septicemic complications. Its prognosis is frankly bad. The treatment is far more difficult. The use of cardiovascular analeptics, such as dopamine, after an infilling failure, is not always sufficient to re-establish the situation. The exeresis of necrotic tissues is an indispensable condition to remove the cause of the shock before septicaemic generalisation.

Adult↗
PubMedDate not supplied

[Loco-regional anesthesia in remote medical units. III. Anesthesia of upper-limb: the intravenous loco-regional anesthesia (author's transl)].

The loco-regional intravenous anesthesia has the great advantage of its simplicity. It is a good complement of the plexic blocks for anesthesia of the upper limb, but it must be discarded in case of lasting interventions because of the tourniquet, or in case of large damages through which the anesthesic fluid leak out, or if a long hemostatic checking may be foreseen.

Anesthesia, Conduction↗
PubMedDate not supplied

Inhibition of angiotensin I-converting enzyme with S 9490: biochemical effects, interspecies differences, and role of sodium diet in hemodynamic effects.

S 9780, the diacid form of S 9490, inhibited guinea pig plasma angiotensin-converting enzyme (ACE) by 50% (IC50) at a concentration of 2.4 +/- 0.1 nM. A Ki of 1.2 nM was obtained for S 9780 (Dixon-Webb plot) with angiotensin I as a substrate. In rabbits, rats, cats, guinea pigs, and dogs, S 9780 MK 422, S 9490, and MK421 decreased, in a dose-dependent manner, the pressor response to angiotensin I. The rabbit and the rat were the most sensitive species, with ID50 values, respectively, of 2.7 +/- 0.4 and 5.9 +/- 0.3 micrograms/kg i.v. for S 9490 and 1.2 +/- 0.2 and 2.6 +/- 0.8 micrograms/kg i.v. for S 9780. S 9490 induced a dose-dependent decrease in serum ACE activity in rabbits (0.6-20 micrograms/kg i.v.) and guinea pigs (10-100 micrograms/kg i.v.). In conscious rats and dogs S 9490 (0.03-1 mg/kg p.o.) induced a long-lasting inhibition of the angiotensin I-induced pressor response; 40% inhibition was recorded in dogs, 24 h after 1 mg/kg p.o. S 9490 (0.03-0.1 mg/kg i.v.) potentiated the increase in femoral blood flow induced by bradykinin injected into the femoral artery of dogs. In anesthetized dogs, mean blood pressure and heart rate were not changed after sodium restriction, but the cardiac output was markedly decreased. S 9490 (0.1-1 mg/kg i.v.) decreased mean blood pressure both in sodium-restricted and sodium-repleted pentobarbital-anesthetized dogs. However, the lowering effect was more pronounced in sodium-restricted dogs. S 9490 (3 mg/kg p.o.) did not change mean blood pressure in conscious dogs maintained on normal-sodium diet but decreased mean blood pressure in conscious sodium-restricted dogs. Plasma renin activity (PRA) and plasma aldosterone concentration were strongly enhanced in conscious dogs maintained on low-sodium diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

Vasopressin and oxytocin in genetically hypertensive rats of the Lyon strain.

To investigate the role of arginine vasopressin (AVP) in genetic hypertension, we measured 24-h urinary volume, osmolality, and 24-h AVP excretion, as well as pituitary and pineal AVP and oxytocin levels, in genetically hypertensive (LH), normotensive (LN), and low blood pressure (LL) 5-and 45-week-old female rats of the Lyon strains. We also determined vascular sensitivity to AVP, norepinephrine, and angiotensin II in 6- and 21-week-old rats. AVP secretion was increased in both LH and LL rats compared with LN controls. Previous reports of increased AVP secretion in spontaneously hypertensive rats have suggested that AVP might play a role in high blood pressure. The existence of a similar increase in LL rats indicates that genetic hypertension of LH rats is not related directly to their increased AVP secretion. Furthermore, the vascular sensitivity to AVP was not specifically enhanced in 21-week-old LH rats compared with LN and LL controls. This study provides evidence against a major role of vasopressin in the genesis and maintenance of high blood pressure in this model of experimental hypertension, and emphasizes that the choice of controls in such investigations is of crucial importance.

Angiotensin II↗