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Biomedical subjects

E V Cosmi

Publications and source records attributed to E V Cosmi.

At least 145 records · Page 8Linked to original sources
PubMed1977

Cutaneous stimulation and generation of breathing in the fetus.

The generation of spontaneous regular breathing by cutaneous stimulation and by direct electrical stimulation of the sciatic nerve was examined in six previously apneic mature fetal lambs in utero. The fetuses were stable throughout the course of the experiments: PaO2 less than or equal to 27 mm Hg, PaCO2 less than 44 mm Hg, pH 7.29-7.34, blood pressure and heart rate steady and normal. It is shown that electrical stimulation of the fetal skin (66 cps, 4.0 msec, 6 V, 0.77 ma) can be as effective as direct stimulation of the sciatic nerve (66 cps, 4.0 msec, 1.5 V, 0.08 ma) when the higher voltage and current are used. Mechanical cutaneous stimulation also produced spontaneous breathing which, however, was short lived compared with that produced by electrical stimuli. The results are consonant with our concept of activation and recruitment of quiescent respiratory center neurones by somatic sensory stimulation, and they give fundamental support to the clinical observation of others that cutaneous stimulation is effective for the treatment of apnea of prematurity. Speculation Somatic sensory stimuli from the skin may be important determinants of the onset of breathing in the fetus and newborn.

Animals↗
PubMed1975

Lamb fetal pulmonary fluid. I. Validation and significance of method for determination of volume and volume change.

An indicator-dilution method is described for measuring fetal pulmonary fluid, FPF, volume (Ve), and volume change with time (Vs) in the lamb fetus in utero. The indicator, albumin, which is the predominant protein of normal FPF, was administered directly to FPF in the form of radio-iodinated human serum albumin (RISA). We have shown that (1) RISA is distributed homogeneously throughout the FPF compartment, (2) it is not altered within FPF, (3) it does not alter the functional characteristics of FPF, and (4) it remains within the FPF compartment throughout the period of measurement. Ve varies directly with the weight of the fetus so that Ve per kilogram was 31.6-35.6 ml/kg in four of five fetuses. The Ve per kilogram was lower in one fetus at the start of the experiment but increased rapidly to 29.0 ml/kg within 45 min. Thus the relaxation volume of the fetus in utero is in the range of functional residual capacity (FRC) and thoracic gas volume of the air-breathing neonate, which indicates that the pulmonary transformation at birth is, in essence, an isovolumic change in state wherein the fetal liquid-lung becomes the neonatal air-lung. The rate at which FPF is formed (Vs) is about 1.5 ml/hr-kg; however, the rate may change in so far as both rapid increases and rapid decreases of FPF volume were observed. When breathing movements were induced in the fetus by stimulation of the sciatic nerve, FPF volume decreased rapidly (Vs equals -3.0 ml/hr-kg), which indicates that negative intrathoracic pressures promote its resorption. When FPF volume fell transiently or was low initially, there was subsequent rapid restoration of volume to the range of anticipated FRC.

Animals↗
PubMed1975

Lamb fetal pulmonary fluid. II. Fate of phosphatidylcholine.

Using the radio-iodinated human serum albumin ([131-I]-RISA) dilution method to measure lamb fetal pulmonary fluid (FPF) volume, we followed the disappearance of protein-complexed, 14-C-labeled phosphatidylcholine ([14-C]PC) during the first 90 min after its injection into FPF. The FPF samples were analyzed for total lipid 14-C activity and for distribution of 14-C in PC, other phospholipids (PL), fatty acids (FA), and neutral lipids (NL). For most sampling periods ascending aortic (AAo) and right atrial (RA) blood samples were obtained simultaneously with FPF and serum was analyzed for total lipid 14-C activity and for distribution of 14-C in total PL, FA, and NL. These studies indicate that (1) PC is cleared rapidly from FPF with an estimated half-time of 15-57 min; (2) FPF-PC may be metabolized to lyso-PC and FA within the fluid itself; and (3) FA derived from PFP-PC enter the pulmonary circulation, thus establishing a pulmonary arteriovenous FA gradient. The possible sites at which PC may be cleared from FPF are considered.

Animals↗