Biomedical subjects

P Mercurio

Publications and source records attributed to P Mercurio.

6 recordsLinked to original sources

PubMed2000

Severe hypoplasia of medullary arcuate nucleus: quantitative analysis in sudden infant death syndrome.

The human arcuate nucleus (ARCn) is postulated to be homologous to ventral medullary cells involved in chemoreception, and respiratory and blood pressure responses. Abnormalities in central respiratory control may result from dysfunction of this anatomic ventral area. We evaluated the changes of the neuronal population of the medullary ARCn in infants victims of the sudden infant death syndrome (SIDS). In this study we tested the hypothesis that anatomical deficiency of the ARCn is associated with SIDS. The volume and neuronal density of the ARCn were morphometrically quantified with an image analyzer in 36 cases of SIDS and 12 age-matched controls. We found a marked hypoplasia in the SIDS ARCn compared to controls and, particularly, in 11 SIDS cases (30%) in which the ARCn exhibited a severe hypoplasia, being almost totally absent. Three-dimensional reconstructions and morphometric measurements of ARCn confirmed this marked hypoplasia in all the serial sections examined (P = 0.0001) and the reduced neuronal density (P = 0.0025) in relation to control cases. In conclusion these abnormalities observed in the ARCn are consistent with the idea that ARCn dysfunction plays an important role among the causative factors of sudden infant death. The hypoplasia of the ARCn represents the most frequent congenital abnormality in our experience, and can be a plausible morphological substrate for a subset of SIDS.

Cell Count↗

PubMed1986

An alternative method for coordinating pulmonary capillary wedge pressure measurements with the respiratory cycle.

Changes in intrathoracic pressure during the respiratory cycle cause variations in pulmonary vascular pressures. This affects pulmonary hemodynamic measurements in critically ill patients, particularly those receiving mechanical ventilation. With certain newer ventilators, the machine-pressure and/or expiratory-flow signal can be graphed simultaneously with hemodynamic pressure. The end-expiratory point determined from these graphs can be used to identify the corresponding wedge pressure on the hemodynamic tracing.

Critical Care↗

PubMed1984

The IPPB trial.

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Aerosols↗

PubMed1983

Echocardiographic evaluation of Carpentier mitral valvuloplasty.

Carpentier's technique for reconstructive mitral valve surgery is an alternative to mitral valve replacement in patients with mitral regurgitation. The procedure involves reconstruction of the mitral valve and insertion of a ring into the mitral anulus. To study the results of this operation, pre- and postoperative M-mode, two-dimensional (2DE), and Doppler echocardiography were performed on 13 patients with severe, symptomatic mitral regurgitation, who underwent reconstructive mitral surgery. A significant clinical improvement was noted in all patients. This correlated with the hemodynamic and angiographic improvement in six of the patients who underwent postoperative cardiac catheterization. Postoperative echocardiography showed that the mitral valve E-F slope decreased from 129 +/- 30 mm/sec preoperatively to 53 +/- 13 mm/sec postoperatively (p less than 0.001). The mitral valve excursion decreased from 28 +/- 6 mm preoperatively to 19 +/- 2 mm postoperatively. The left ventricular minor axis shortening decreased from 32 +/- 9% to 28 +/- 6%. In seven patients the mitral valve area decreased from 4.5 +/- 0.9 cm2 to 2.8 +/- 0.5 cm2 (p less than 0.005). In each patient a new echocardiographic finding was observed: two parallel dense linear echoes from the prosthetic ring were noted on M-mode echocardiography near the base of the mitral valve. 2DE visualized the entire ring. Doppler echocardiography suggested moderate or severe mitral regurgitation in eight of eight patients studied preoperatively. Postoperatively 10 of 11 patients had no Doppler echocardiography finding of mitral regurgitation.

Adolescent↗

PubMed1982

Spasm of a normal or minimally narrowed coronary artery in the presence of severe fixed stenoses of the remaining vessels: clinical and angiographic observations.

Four patients with medically refractory unstable angina are presented. Each patient had ST-segment abnormalities during some episode of pain. Three patients had at least one episode of documented ST-segment elevation with their spontaneously occurring chest pain. One had recurrent ventricular tachycardia. Two patients had prior myocardial infarction. Angiography demonstrated localized left ventricular akinesis and a severe fixed stenosis in the coronary artery supplying the abnormal segment. There were severe, fixed lesions in two coronary arteries in two patients and in one vessel in two patients. After i.v. ergonovine maleate, coronary artery spasm was documented in a normal or minimally diseased coronary artery in each patient. In two patients, ergonovine-induced spasm not only occluded the vessel, but also markedly decreased retrograde filling of a vessel with severe, fixed narrowing. Each patient's characteristic symptoms appeared with the ergonovine-induced spasm. Thus, ergonovine maleate can provoke spasm of a normal coronary artery, even in the presence of severe fixed stenoses of the remaining vessels. This observation may have an important role in the diagnosis and clinical management of patients with chest pain.

Adult↗

PubMed1980

Methods of intermittent positive pressure breathing.

Inspiratory capacity (IC) was evaluated in 60 patients during the following four respiratory maneuvers: (1) coached unassisted inspiration; (2) inspiratory positive-pressure breathing (IPPB) at 15 cm H2O with the patient passively inspiring; (3) IPPB at 15 cm H2O with the patient coached to actively inspire; and (4) IPPB at a peak pressure adjusted according to the judgment of the respiratory therapist, with the patient coached to actively inspire. The IC attained with these maneuvers were, respectively, as follows: (1) 1.29 +/- 0.75 L; (2) 1.13 +/- 0.52 L; (3) 1.77 +/- 0.11 L; and (4) 2.27 +/- 0.11 L (mean +/- SE). The peak ventilator pressure for maneuver 4 averaged 30 +/- 7 cm H2O (mean +/- SD), and no patient experienced harmful side effects from these peak pressures. These data indicate that the method of treatment with IPPB has profound effects upon the degree of pulmonary expansion. All research on therapy with IPPB should be carefully controlled for the method of administering IPPB, and the volumes obtained during the treatment should be carefully documented before general conclusions are drawn concerning the effects of IPPB on morbidity. For the present, we suggest that IPPB, when administered clinically, be given as described in method 4.

Adult↗