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Biomedical subjects

G Sedin

Publications and source records attributed to G Sedin.

At least 109 records · Page 6Linked to original sources
PubMed1981

Water transport through the skin of newborn infants.

Factors that may influence the water transport through the skin in infants on their first day of life were studied with a method based on determination of the vapour pressure gradient in the air layer close to the skin surface. The evaporation rate from the skin was found to vary with the site of measurement, ambient humidity, temperature, activity, gestational age and nutritional status at birth. Differences related to maturity were shown to decrease with postnatal age.

Biological Transport↗
PubMed1980

Functional residual capacity and ventilatory pressures during positive-pressure ventilation at high frequencies.

The functional residual capacity (FRC) was measured in cats by the nitrogen washout technique during positive-pressure ventilation. Frequencies of 60 and 100 b.p.m. were used with insufflation periods of 20% and 35% of the ventilatory cycle, without and with a positive end-expiratory pressure. The higher frequency combined with the shorter insufflation period gave FRC close to that obtained during spontaneous breathing. The lower frequency and the longer insufflation period always gave greater FRC values. A further increase in FRC of about 23-27% was obtained after application of a positive end-expiratory pressure of 0.5 kPa. Adequate ventilation was achieved with small intratracheal and intrapleural pressures at all settings used.

Animals↗
PubMed1980

Transepidermal water loss in newborn infants. IV. Small for gestational age infants.

Using a method described earlier, the evaporation rate (ER) from the skin was studied at different ambient humidities in 14 full-term and 10 pre-term small for gestational age (SGA) infants. Transepidermal water loss (TEWL) was estimated in 25 SGA infants born after 30-40 weeks of gestation. Comparisons were made with infants appropriate for gestational age (AGA). A linear relationship was found between ER and ambient humidity in full-term SGA infants, but with lower ER values than in AGA infants. Lower ER values were also found in moderately pre-term SGA infants at different ambient humidities. ER was higher at lower ambient humidities in both SGA and AGA infants. In full-term and moderately pre-term SGA infants TEWL was lower than in corresponding AGA infants.

Female↗
PubMed1980

Transepidermal water loss in newborn infants. V. Evaporation from the skin and heat exchange during the first hours of life.

The amount of water evaporated from the skin was studied in 10 healthy newborn infants from their first minute of life, while being taken care of in the delivery room, and in 11 infants treated in incubators from their 30th min of life. The heat lost by evaporation, radiation and convection was calculated. Evaporation from the skin was very high during the first minutes after birth and was the main cause of heat loss during the first 15-30 min of life. Thereafter the amount of heat lost depended on the conditions under which the infant was nursed. Higher convective and radiative heat losses were found in delivery rooms than in incubators.

Body Temperature Regulation↗
PubMed1980

Meningitis in a newborn infant caused by Mycoplasma hominis.

When 10 days old an infant born after 34-35 weeks of gestation developed meningitis with pleocytosis and a low glucose concentration in the cerebrospinal fluid. Mycoplasma hominis was recovered from the cerebrospinal fluid and treatment with doxycycline was given. The strain was later found to be resistant to tetracycline. After institution of lincomycin, cultures for mycoplasmas were negative. The infant, who during the course of the meningitis had developed a transient increase in intracranial pressure, was healthy and normally developed at the age of one year.--This is the first report on an infection caused by a tetracycline-resistant strain of Mycoplasma hominis.

Drug Resistance, Microbial↗
PubMed1979

Transepidermal water loss in newborn infants. II. Relation to activity and body temperature.

Using a method described in a previous article the transepidermal water loss (TEWL) was studied in 10 healthy newborn infants at rest and during activity. On the average TEWL was 37% higher during activity than during rest although no sweating was observed. In 9 infants placed in incubators with an ambient temperature slightly above the thermoneutral range measurements were made as the body temperature rose. TEWL was almost constant until a temperature of 37.1 degrees C was reached whereupon the water loss suddenly increased as the infant started sweating.

Birth Weight↗
PubMed1979

Transepidermal water loss in newborn infants. III. Relation to gestational age.

Using a method described earlier, the evaporation rate (ER) was studied at different humidities in 12 newborn infants born after 25 to 30 weeks of gestation and 10 infants born after 32 to 35 weeks. Transepidermal water loss (TEWL) was estimated in 32 infants born after 25 to 39 weeks of gestation. The ER values were highest in the infants with the lowest gestational age and the susceptibility to changes in ambient humidity was also greater at lower gestational ages. An exponential relationship was found between TEWL and gestational age. TEWL being 15 times higher in infants born after 25 weeks of gestation than in full-term infants.

Birth Weight↗
PubMed1977

Transepidermal water loss in newborn infants. I. Relation to ambient humidity and site of measurement and estimation of total transepidermal water loss.

Insensible water loss (IWL) is an important factor in the thermoregulation and water balance of the newborn infant. A method for direct measurement of the rate of evaporation from the skin surface has been developed. The method, which is based on determination of the vapour pressure gradient close to the skin surface, allows free evaporation. From measurements performed on 19 newborns placed in incubators, a linear relation was found between the evaporation rate (ER) and the humidity of the environment at a constant ambient temperature. A 40% lower ER was recorded at a high relative humidity (60%) than at a low one (20%) in the incubator. At measurements on different sites of the body, a high ER was observed on the face and peripheral parts of the extremities, while ER at other sites was relatively low. By determining ER from different parts of the body and calculating the areas of the corresponding surfaces, the total cutaneous insensible water loss for the infant in question could be obtained. The transepidermal water loss (TEWL) for the whole body surface area was calculated to be 8.1 g/m2h. On the basis of measurements performed it was found that the total cutaneous insensible water loss can be estimated with a reasonable degree of accuracy by recording ER from only three easily accessible measurement points.

Birth Weight↗
PubMed1976

Responses of the cardiovascular system to carotid sinus nerve stimulation.

The changes in blood pressure, heart rate, cardiac output and blood flow in the femoral and common carotid arteries on carotid sinus nerve stimulation (CSNS) were studied in chloralose anaesthetized dogs, both with spontaneous heart rhythm and during atrial pacing. Stimulation of the sinus nerves with impulse trains and with impulses of constant frequency had almost equal effects on the blood pressure. The former had a greater effect on the heart rate; these findings verified earlier observations. The reductions in cardiac output followed those in heart rate. During atrial pacing the stroke volume was reduced on CSNS. The total peripheral resistance, regional peripheral resistances and input impedance of the vascular bed of the femoral artery were calculated. The initial effects of CSNS varied in relation to the prestimulation total peripheral resistance and to stimulation frequency. Differences between stimulation with a constant frequency and the intermittent types, with the same number of impulses per cardiac cycle, were negligible as regards effects on stroke volume, blood flow and regional vascular resistances. CSNS caused changes in input impedance of the vascular bed of the femoral artery which were very similar to those observed earlier on intraarterial injection of vasodilator drugs. The different effects of intermittent and constant frequency CSNS on the heart rate in dogs with intact vagal nerves and no clamping of the common carotid arteries might be caused by asymmetries in the autonomic effects on the S.A. node. The neurophysiological mechanisms are discussed. It is deduced that greater reductions in blood pressure with intermittent stimulation are only obtained in the pre-existence of a high sympathetic tone.

Adaptation, Physiological↗