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Biomedical subjects

R Natale

Publications and source records attributed to R Natale.

At least 55 records · Page 3Linked to original sources
PubMed1983

The effect of maternal hyperglycemia on gross body movements in human fetuses at 32-34 weeks' gestation.

This study demonstrated that fetal gross body movements were not significantly altered by fluctuations in maternal plasma glucose concentration. Fetuses moved episodically a relatively constant amount of time whether mother received water orally, 50 g of glucose orally or a 25 g bolus of glucose intravenously. In addition, depending on the length of the observational epoch, the incidence of fetal gross body movements differed. As the length of the observational period increased, the chance of finding no fetal gross body movements decreased and at intervals of 24 min duration, fetal gross body movements were absent in only 2% of 24 min periods examined, irrespective of whether they had received water orally, 50 g of glucose orally or 25 g of glucose intravenously. It is concluded that maternal carbohydrate intake was not an important determinant of fetal body movements in healthy fetuses at 32-34 weeks' gestation.

Blood Glucose↗
PubMed1982

Effects of intravenous glucose injections on human fetal breathing movements and gross fetal body movements at 38 to 40 weeks' gestational age.

Fetal breathing movements and gross fetal body movements were studied subsequent to the intravenous injection of either 25 gm of glucose or an equal volume of normal saline solution in 10 healthy women with uncomplicated pregnancies at 38 to 40 weeks' gestation. The incidence of fetal breathing increased from 17.5% during the control period to 54.9% after glucose injection. Neither glucose nor saline solution had any effect on the incidence of gross fetal body movements. All fetuses made some breathing movements during any 15-minute interval between 30 and 75 minutes after glucose injection. These data suggest a useful strategy for clinical measurement of fetal breathing activity near term.

Apgar Score↗
PubMed1982

Patterns of gross fetal body movements over 24-hour observation intervals during the last 10 weeks of pregnancy.

Continuous measurements of gross fetal body movements were made with an ultrasonic real-time scanner for periods of 24 hours in 31 women. Fetuses made 0 to 130 gross fetal body movements per hour which accounted for 0% to 50% of the time. At 38 to 39 weeks' gestational age, fetuses demonstrated a peak in activity between 2100 and 0100 hours. The longest period of complete absence of gross fetal body movements was 75 minutes. Maternal meals and glucose concentrations did not influence gross fetal body movements.

Activity Cycles↗
PubMed1981

Measurement of fetal forelimb movements in the lamb in utero.

Forelimb movements in the unanesthetized fetal lamb in utero were measured by means of transit-time ultrasound in conjunction with triceps and biceps electromyographic activity. The relationships between forelimb movements and electrocortical activity, hypoxia, and spontaneous labor were studied. There was no evidence of diurnal variation. The amount of time spent moving in low-voltage electrocortical activity with rapid eye movements was significantly less than in other electrocortical states. During acute hypoxia, forelimb movements were much reduced. In active labor near term, the fetal electrocorticogram continued to cycle between high- and low-voltage activity, and the number of movements was reduced; movements were present only during uterine contractions, provided that the fetus was not in low-voltage electrocortical activity with rapid eye movements.

Animals↗
PubMed1980

A definition of human fetal apnea and the distribution of fetal apneic intervals during the last ten weeks of pregnancy.

Fetal breathing movements were studied over 24-hour observation periods for a total of 744 hours in 31 healthy pregnant women at 30 to 39 weeks' gestational age. An analysis of 165,786 breath-to-breath intervals in eight fetuses demonstrated that 97% of breath-to-breath intervals were less than 6 seconds in duration. It was concluded that a breath-to-breath interval of 6 seconds or more is a rational definition of fetal apnea during the last 10 weeks of pregnancy. An analysis of intervals during which time no fetal breathing activity occurred in the 31 fetuses demonstrated that prolonged episodes of apnea were distributed in a similar fashion at different gestational ages. The longest periods of apnea were 65 minutes at 30 to 31 weeks, 105 minutes at 34 to 35 weeks, and 120 minutes at 38 to 39 weeks. No periods of apnea of more than 45 minutes were measured during the second and third hours following maternal meals. A useful strategy for recognition of significant fetal apnea would be to make observations during the second and third hours following maternal meals when apneic lengths greater than 45 minutes were not observed in this highly selected group of normal fetuses.

Apnea↗
PubMed1980

Circadian rhythms in maternal plasma cortisol and estriol concentrations at 30 to 31, 34 to 35, and 38 to 39 weeks' gestational age.

In order to examine the relationship between circadian rhythms in different steroids, cortisol and estriol were measured by radioimmunoassay in maternal venous plasma taken at 30- to 60-minute intervals over 24 hours from nine healthy women at 30 to 31, 11 at 34 to 35, and 10 at 38 to 39 weeks' gestation. Maternal cortisol was maximal at 0730 to 0830 hours and fell significantly to its lowest concentration between 1830 and 0130 hours. At 30 to 31 and 34 to 35 weeks there was a significant circadian rhythm in estriol concentrations which was inversely related to the circadian rhythm in cortisol. At 38 to 39 weeks mean estriol concentrations were significantly higher than those at 30 to 31 and 34 to 35 weeks but there was no significant circadian pattern. We concluded that there is an inverse relationship between maternal cortisol and estriol at 30 to 31 and 34 to 35 weeks, which would be consistent with a maternal effect on fetal adrenal function. The increase in mean concentration and absence of circadian rhythm in maternal plasma estriol at term might suggest an additional positive stimulus to fetal adrenal function. The existence of patterns in maternal estriol concentrations must be taken into account in the u;se of sequential measurements of this hormone during the last 10 weeks of pregnancy.

Circadian Rhythm↗
PubMed1980

Diurnal changes in maternal plasma oestrone and oestradiol at 30 to 31, 34 to 35 and 38 to 39 weeks gestational age.

Diurnal changes in the concentrations of oestrone (E1) and oestradiol (E2) in maternal peripheral plasma have been measured in samples of blood taken at one hour intervals from women at 30 to 31, 34 to 35 and 38 to 39 weeks of pregnancy. There was a significant effect of time of sampling on the plasma concentration of E1 at all stages of gestation, and circadian changes in the levels of E1 were apparent at 34 to 35 and 38 to 39 weeks. Peak values were measured around 0830 to 0930 hours, and troughs occurred between 0130 and 0530 hours. Significant effects of time of sampling on the plasma concentration of E2 were found at 34 to 35 and 38 to 39 weeks of pregnancy; night-time concentrations were lower than the peak values at 0730 to 0830 hours. The relation of these changes to the circadian rhythms in the concentrations of cortisol and oestriol in maternal plasma are discussed.

Circadian Rhythm↗
PubMed1980

Concentrations of oxytocin in the plasma and amniotic fluid of rhesus monkeys (Macaca mulatta) during the latter half of pregnancy.

A specific radioimmunoassay for oxytocin has been established with a sensitivity of 0.8 pg/tube. This assay has been applied to the measurement of oxytocin in serial samples of peripheral plasma and amniotic fluid from pregnant rhesus monkeys, collected at weekly intervals by venepuncture and amniocentesis. Concentrations of oxytocin in both fluids were generally low and showed no trends throughout the latter half of gestation.

Amniotic Fluid↗
PubMed1980

Maternal plasma glucose concentration and fetal breathing movements: a review.

In summary, studies have demonstrated that administration of glucose to normal pregnant females resulted in increased fetal breathing movements in the second and third hour of observation if the glucose was given orally or within the first and second hour of observation 30 min following the administration of a 25-g glucose intravenous bolus. No relationship was demonstrated between maternal plasma glucose concentration and fetal breathing rate or the occurrence of fetal hiccoughs. Furthermore, gross fetal body movements were independent of fluctuations in maternal plasma glucose concentration. Although it may be possible that local excess of carbon dioxide produced by increased oxidation of glucose might have stimulated the chemosensitive areas in the brain stem and produced increased fetal breathing activity, the mechanism for the increased fetal breathing following maternal administration of glucose remains to be elucidated. It would seem that in any short-term studies in which fetal breathing, fetal movement, and other fetal biophysical parameters are being recorded, the experimental approach must take into consideration the episodic nature of fetal breathing and gross body movements, the prandial state of the mother, the time of day, and the gestational age at which the studies are performed. The evidence for the clinical usefulness of standardized approaches of looking at fetal breathing in conjunction with other biophysical parameters remains to be presented.

Animals↗
PubMed1980

Patterns of human fetal breathing during the last 10 weeks of pregnancy.

Continuous measurements of human fetal breathing movements and gross fetal body movements were made with an ultrasonic real-time scanner for periods of 24 houro 31 weeks' gestation, a significant increase in fetal breathing movements occurred during the second and third hours after meals; this pattern apparently followed an increase in maternal plasma glucose concentrations. At 38 to 39 weeks' gestation, fetal breathing movements increased during the second and third hours after breakfast, but the troughs seen before lunch and supper at 30 to 31 weeks' gestation were not present. Fetal breathing movements diminished over the day and reached a minimum between 1900 and 2400 hours. Fetal breathing activity increased in both groups between 0400 and 0700 hours while mothers were asleep; this was not related to an increase in maternal glucose concentrations. Absence of fetal breathing movements was observed for up to 122 minutes in this analysis of 480 hours in 20 patients. These data show that much more information must be obtained on factors that normally influence fetal breathing activity. Only then can research strategies be suggested for clinical evaluation of the usefulness of fetal breathing movements in the assessment of fetal health.

Blood Glucose↗
PubMed1979

Circadian rhythms in maternal plasma cortisol, estrone, estradiol, and estriol at 34 to 35 weeks' gestation.

In order to examine the relationship between circadian rhythms in different steroids, cortisol (F), estrone E1), estradiol (E2), and estriol (E3) were measured by radioimmunoassay in maternal venous plasma taken at 30 to 60-minute intervals over 24 hours from 11 healthy women at 34 to 35 weeks' gestation. Maternal F was maximal at 0730 hours and fell significantly to its lowest concentration at 0230 hours. Maretnal E3 was lowest between 1000 and 1130 hours and rose significantly to maximal values between 2230 and 0030 hours. Maternal E1 was maximal between 1000 and 1130 hours and showed a significant decrease to reach its lowest concentration at 0430 to 0630 hours. No significant circadian change was measured in uncorrected concentrations of E2. We conclude that there is an inverse relationship between maternal F and E3, which would be consistent with a maternal effect on fetal adrenal function, and the existence of circadian rhythms in F, E1, E2, and E3 must be taken into account in clinical investigations of these hormones during pregnancy.

Circadian Rhythm↗
PubMed1979

Human fetal breathing activity during electively induced labor at term.

Human fetal breathing movements were measured during the first stage of electively induced labor in 20 healthy term pregnancies. Fetuses made breathing movements 25.6% of the time during a 1 hour control period and breathing decreased significantly to 8.3% during latent-phase labor and further decreased to 0.8% during active labor (P less than 0.001). Patterns of increased fetal breathing activity accompanied by increased gross fetal body movements and increased fetal heart rate variability for periods of 20 to 60 minutes out of every 1.0 to 1.5 hours were observed, and the intermittent patterns of increased body movement and heart rate variability continued throughout the first stage of labor despite the decrease in fetal breathing activity during latent- and active-phase labor. It will be important to account for rest activity patterns when interpreting variability of heart rate during labor. The absence of fetal breathing activity during electively induced labor at term is not a clinical indicator of fetal ill health.

Anesthesia, Epidural↗
PubMed1979

Prostaglandin E, thromboxane B2 and 6-oxo-prostaglandin F1 alpha in amniotic fluid and maternal plasma of rhesus monkeys (Macaca mulatta) during the latter third of gestation.

The concentrations of prostaglandin E (PGE), thromboxane B2 (TXB2) and 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha) were measured by radioimmunoassay in serial samples of amniotic fluid and maternal peripheral plasma in the latter third of pregnancy in rhesus monkeys (Macaca mulatta). The samples were collected under ketamine-induced anaesthesia. The concentration of PGE was undetectable in amniotic fluid until a few days before delivery when a large increase was observed in three of the five animals. There were small increases of TXB2 and 6-oxo-PGF1 alpha in amniotic fluid before delivery. In maternal plasma the concentrations of PGE, TXB2 and 6-oxo-PGF1 alpha were generally higher and more variable than in amniotic fluid and did not increase with advancing gestation. It is suggested that increased production of primary prostaglandins occurs before, and is involved in, the onset of parturition in the rhesus monkey.

Amniotic Fluid↗
PubMed1978

Patterns of human fetal breathing activity at 34 to 35 weeks' gestational age.

Continuous measurements of human fetal breathing movements at 34 to 35 weeks' gestational age were made with an ultrasonic real-time scanner for periods of 24 hours in 11 women. A significant increase occurred in fetal breathing activity during the second and third hour following meals and this pattern apparently followed an increase in maternal plasma glucose concentration. There was a prolonged significant increase in fetal breathing activity between 0100 and 0700 hours. Increases in human fetal breathing activity accompanied by increased gross fetal body movements occurred for periods of 20 to 60 minutes out of every 1.0 to 1.5 hours of observation time. It was concluded that the percentage of time spent breathing by normal fetuses was related to time of day and maternal meals. The alternating changes of fetal activity and inactivity observed may represent biologic changes of sleep state in the human fetus in utero at 34 to 35 weeks' gestational age. It will be important to account for these three patterns of fetal breathing activity in clinical studies which examine the usefulness of fetal breathing movements in assessing fetal health.

Abdominal Muscles↗
PubMed1978

Effects of human maternal venous plasma glucose concentrations on fetal breathing movements.

Human fetal breathing movements were studied following the maternal ingestion of either a 50 Gm. oral glucose load or an equal volume of water in 22 healthy women with uncomplicated pregnancies at 32 to 34 weeks' gestation. The percentage of time spent breathing in fetuses of glucose-treated mothers increased from 23.2 +/- 2.2 per cent during the control period to a maximum of 58.9 +/- 5.2 per cent at 105 minutes following the oral glucose load (p less than 0.01) which was one hour following the peak maternal plasma glucose concentration. No similar increase in maternal glucose concentrations or percentage time spent breathing occurred in patients receiving water. Fetal breathing movements were observed in 97 per cent of the 15 minute periods during the second and third hour after maternal ingestion of a 50 Gm. oral glucose load. It was concluded that maternal carbohydrate intake two hours prior to fetal breathing observations should be documented to permit adequate interpretation of fetal breathing activity.

Administration, Oral↗