The prenatal ultrasonographic diagnosis of cardiomegaly due to tricuspid incompetence.
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Adult↗
Biomedical subjects
T R Gunn
Publications and source records attributed to T R Gunn.
Genioglossus and alae nasi activity in fetal sheep.
The functional development of two upper airway dilating muscles, the alae nasi and the genioglossus, has been studied in fetal sheep in utero from 112-140 days gestation. Before electrocortical differentiation phasic activity was present in both muscles for long periods, mostly when breathing movements were present. After 120 days gestation phasic genioglossal and alae nasi activity occurred only during periods of low voltage electrocortical activity. During high voltage episodes there was no phasic activity and tonic activity was not sustained. Although present during periods of breathing movements genioglossus activity was rarely synchronous with the diaphragm. The alae nasi showed both respiratory and non-respiratory related activity. Hypoxia abolished both alae nasi and genioglossus activity but whereas alae nasi rapidly developed an inspiratory rhythm during 5% CO2 administration this was not the case with the genioglossus and inspiratory activity was not always seen in the genioglossus even during 10% CO2 administration. It is concluded that there are fundamental differences between the control of genioglossus and alae nasi activity in the fetal sheep. The alae nasi behaves as an inspiratory muscle responding to hypoxia and hypercapnia as would be expected but the genioglossus shows no inspiratory activity during normal unstimulated fetal breathing. Thus the neural mechanisms for activation of inspiratory activity appear to be present late in gestation. However it is possible for the genioglossus to develop an inspiratory rhythm under conditions of much increased respiratory drive.
Animals↗
Metabolic and hormonal responses to cooling the fetal sheep in utero.
The metabolic and hormonal effects of cooling 10 fetal sheep in utero (115-142 days of gestation) for 2h were studied. The fetal core temperature fell by 2.81 +/- 0.14 degrees C while the maternal temperature fell 0.86 +/- 0.15 degrees C. This hypothermia caused a significant rise in the fetal and maternal plasma glucose concentrations (P less than 0.001) and a fall in the fetal insulin concentrations (P less than 0.01). The fetal plasma lactate and cortisol concentrations rose rapidly (P less than 0.01) while the growth hormone fell (P less than 0.01) and remained low until cooling ceased when a rapid rebound occurred. There was no significant change in any of the fetal iodothyronines and no elevation of nonesterified free fatty acid concentrations, in contrast to the rapid rise (P less than 0.01) which occurred when newborn lambs were cooled. These observations demonstrate that appropriate glucose, insulin, lactate and cortisol responses to hypothermia have differentiated by 120 days of gestation. However, neither a thyroid hormone response nor an elevation in free fatty acid levels was observed. Thus not all components of the thermogenic response to hypothermia can be demonstrated in the late gestation fetail sheep in utero.
Animals↗
Intracranial haemorrhages in Pacific Islander stillbirths: is traditional massage the cause?
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Cerebral Hemorrhage↗
Circulating thyrotropin in the ovine fetus: evidence for pulsatile release and the effect of hypothermia in utero.
The secretion of thyrotropin (TSH) has been investigated in the chronically catheterized ovine fetus (term 145-150 days). Forty-two random plasma samples from 25 fetuses (86-149 days of gestation) were measured for TSH concentrations by radioimmunoassay. Plasma TSH concentrations were highest in the youngest fetuses [86-110 days, 3.9 +/- (SD) 5.5 microU/ml, n = 13]. Thereafter TSH concentrations declined to 0.4 +/- 0.6 microU/ml (n = 13, p less than 0.05) at 130-150 days of gestation. However, serial sampling at 15-20 min intervals for 180 min from 14 individual fetuses (91-139 days) showed that TSH was secreted in a markedly exaggerated pulsatile manner compared to that observed after birth. The mean amplitude of TSH pulses fell (p less than 0.005) from 5.9 +/- 8.1 microU/ml in the fetuses to 2.1 +/- 1.1 microU/ml in five neonatal lambs (6-22 days) and to 1.5 +/- 0.4 microU/ml in three adult nonpregnant ewes. The mean pulse frequency for the 14 fetuses was 0.7 +/- 0.3 pulses/h and was reduced (p less than 0.001) to 0.3 +/- 0.1 pulses/h in lambs and to 0.3 +/- 0.1 pulses/h in the ewes. In the neonate, hypothermia is a potent stimulus to TSH release. To examine the ontogeny of this response, the temperature of the fetus in utero (106-127 days of gestation) was lowered by circulating water (14-18 degrees C) at either a fast or slow rate through a coil placed either externally around the fetus or internally in the fetal esophagus and stomach.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Haemodynamic and catecholamine responses to hypothermia in the fetal sheep in utero.
Chronically catheterised fetal sheep (117-134 days) were cooled in utero via a tubing coil placed around the fetal trunk through which cold water was circulated for one hour. The fetal core temperature was reduced by 5.51 +/- 0.61 degrees C. This hypothermia was associated with tachycardia (P less than 0.001) and hypertension (P less than 0.001) (n = 12). The tachycardia was abolished by treatment with propranolol (n = 4) and the hypertension by treatment with phentolamine (n = 5). Blood flow in the left umbilical artery was measured by an electromagnetic flow probe in 4 fetuses and rose (P less than 0.001) with fetal cooling. The increase in blood flow was abolished by treatment with either phentolamine or propranolol. These observations are consistent with a redistribution of fetal blood flow from peripheral tissues to placental and thermogenic tissues during cooling. Fetal plasma adrenaline and noradrenaline concentrations rose (P less than 0.01) during fetal cooling (n = 5). These studies demonstrate that catecholamine and cardiovascular responses to environmental hypothermia have differentiated prior to birth in the sheep fetus.
Animals↗
The incidence of breast feeding and reasons for weaning.
All 186 mothers delivered in a one month period at St Helens Hospital, Auckland, were interviewed on admission to hospital regarding their attitude to breast feeding and were followed until the infant was weaned or six months of age to determine the reason for weaning. One hundred and fifty-two (82%) of mothers were breast feeding on discharge, 34 (18%) were artificially feeding and only three of these had planned to breast feed before delivery. Racial characteristics were important, with only 7.5% Pacific Island mothers leaving hospital bottle feeding compared to 20% European and 29% of the Maori mothers. Marital status also influenced feeding as 14% of the married mothers left hospital bottle feeding compared to 20% of those in a de facto relationship and 29% of the single mothers. Only 23% of the mothers were still breast feeding at six months of age. The mean age of weaning was 15 +/- 9 weeks and the major reason for weaning was that of an inadequate milk supply in 54%. Despite the high proportion of mothers breast feeding on discharge from hospital, the rapid falloff in breast feeding following discharge highlights the need for improved education of the mothers.
Adolescent↗
Unexplained intracranial haemorrhage in utero: the battered fetus?
Twenty stillborn infants with unexplained intracranial haemorrhages were identified in a review of approximately 3,500 perinatal postmortems performed between 1966 and 1982. After apparently uneventful pregnancies, fetal death occurred before the onset of labour and was recognized at a mean of 10 days before delivery; 80% had subdural haemorrhages, others had intraventricular and/or intracerebral haemorrhages, and many had haemorrhages at more than one of these sites. These haemorrhages were of sufficient size to have caused death and no other causes were found at postmortem examinations. All 20 mothers were immigrants to New Zealand from the Pacific Islands and almost all were older, married, multi-gravidas with uneventful medical histories and in stable socio-economic circumstances. In the period studied the incidence of stillbirths with unexplained intracranial haemorrhages was 1.15 per 1,000 Pacific Islander births and, at one hospital, these haemorrhages were found in 14.6% of Pacific Islander stillbirths. There were no unexplained intracranial haemorrhages in other racial groups. Prenatal subdural haemorrhage without a history of maternal trauma is extremely rare. In the absence of supporting maternal histories and other fetal or maternal injuries the possibility that these are 'battered' fetuses remains circumstantial.
Adult↗
Difficulties in the neonatal diagnosis of Menkes' kinky hair syndrome--trichopoliodystrophy.
The recognition of Menkes' kinky hair syndrome, trichopoliodystrophy, may present problems in the early neonatal period. The serum copper, and ceruloplasmin levels are within the range of normal infants in the first week of life; they are higher than normal in the cord blood of affected infants and fall gradually. Pili torti may only develop later, as the primary fetal hair is normal. The baby may appear bald, or both normal and abnormal hair may be found in different areas of the skull. The roentgenographic signs of wormian bones in the skull, metaphyseal spurring of the long bones, and diverticuli of the bladder develop progressively and may not be seen until after 6 weeks of age. However, diagnosis is possible in the neonatal period, if male infants with unexplained hypothermia, hypotonia, septicemia, or seizures are investigated by serum copper and ceruloplasmin levels after 1 month of age.
Brain Diseases, Metabolic↗
Antenatal education: does it improve the quality of labour and delivery?
Of 196 nulliparous women who delivered in a two month period, 78 percent had attended antenatal education classes. The mothers who did not attend antenatal classes consisted of significantly more Maori and Pacific Island mothers, they were younger, smoked more, had a lower socioeconomic status and fewer were married. The group who went to antenatal education classes had a significantly longer second stage in labour and required more forceps assistance during delivery compared to non-attenders. These results remained for the polynesian mothers, when they were analysed separately and the differences in age and socioeconomic status were no longer present. There was no difference in the type of pain relief required during childbirth by the attenders or non-attenders. We found no evidence that attending antenatal education classes will ensure an easy and less complicated childbirth.
Age Factors↗
Studies of insulin-like growth factor -I and -II by specific radioligand assays in umbilical cord blood.
Somatomedin concentrations in human umbilical sera (n = 206) were measured using a specific radioimmunoassay for insulin-like growth factor (IGF)-I and a specific radioreceptor assay for IGF-II following acid-ethanol extraction of the sera to remove the somatomedin binding proteins. IGF-I concentrations were lower (P less than 0.001) than adult values and correlated with gestational age (P less than 0.001) and birth weight (P less than 0.0001). Multiple regression analysis demonstrated that both birth weight expressed independently of gestational age as the standard deviate score (P less than 0.0001) and gestational age (P less than 0.002) had effects on umbilical cord IGF-I concentrations. IGF-II concentrations were similar to adult values and did not correlate with gestational age, birth size or IGF-I values. IGF-II concentrations were higher (P less than 0.005) in male than female fetuses. These data support a role for IGF-I in influencing fetal growth and suggest the independent regulation of the secretion of IGF-I and II in the perinatal period. These was no evidence to suggest a distinct perinatal form of somatomedin.
Birth Weight↗
Outcome at school-age after neonatal mechanical ventilation.
103 school-age children (5 to 12 years) who survived mechanical ventilation for neonatal respiratory failure were evaluated for growth, neurological, intellectual, psychological and school function in order to determine those children most at risk for handicap. A major handicap occurred in seven children, preventing attendance at normal school or normal classes. Neurological sequelae were significantly associated with perinatal asphyxia and with birthweights of 1500g or less, and neurological sequelae and socio-economic factors were the major determinants of ability. The effects of the Neonatal Intensive Care Unit (NICU) experience on parents and subsequent parent-child relationships were also investigated: 67 per cent of the mothers were very upset by the experience and many continue to worry excessively about the health of their child. Parents who visited their child in the NICU frequently were significantly more anxious and overprotective, restricting many activities even when the child was of school age.
Birth Weight↗
The effect of cooling on breathing and shivering in unanaesthetized fetal lambs in utero.
The effects of cooling have been studied in chronically instrumented unanaesthetized fetal lambs of 106-132 days gestation. Cold stimulation of cutaneous thermoreceptors by means of a coil placed around the fetus in the amniotic cavity induced continuous breathing which was associated with high-voltage electrocortical activity throughout the cooling period. Direct internal cooling by means of an intragastric cooling coil did not alter fetal breathing or sleep-state patterns. Shivering occurred in response to both external and internal cooling, and this response was present as early as 106 days gestation, well before the appearance of high-voltage sleep. In older fetuses there was evidence of a reduction in thermoregulatory responses during low-voltage electrocortical activity, but not of the complete suspension of thermoregulation characteristic of low-voltage (r.e.m.) sleep seen in mature animals. It is concluded that deep regular breathing associated with high-voltage electrocortical activity can be induced by cold stimulation of cutaneous thermoreceptors, but not by a reduction in core temperature alone. Furthermore, fetal responses to cooling are present as early as 106 days gestation.
Animals↗
Development of temperature regulation in the fetal sheep.
To investigate the development of fetal thermoregulatory mechanisms the temperature of the ovine fetus in utero was altered by circulating water through a coil placed around the fetus. In 18 fetuses (76-142 days), temperature recordings were made from thermister probes placed in the fetal cranium below the frontal lobes, the fetal rectum, the amniotic cavity and the maternal vena cava. Severe hypothermia was observed during fetal surgery; the maximum decrement in fetal brain temperature ranged between -7.38 degrees C and -0.83 degrees C and was correlated inversely with gestational age (P less than 0.005). The temperature of the live fetal sheep in utero was 39.05 to 40.37 degrees C and was always greater than the maternal temperature by 0.30 to 0.78 degrees C. The amniotic fluid was intermediate in temperature between the fetus and mother. During cooling studies the fetal cranial temperature fell more quickly and to a greater extent (P less than 0.05) than the fetal rectal temperature. When the cooling was continued for 60 min, a steady fall in fetal temperature was observed until a plateau was reached at 20 to 40 min. The recovery time increased with increasing gestational age (P less than 0.001) suggesting that thermoregulation is still immature in late gestation. During prolonged cooling, fetal hypoxaemia and acidosis were observed.
Animals↗
Diagnosis of unsuspected abdominal abnormalities by perinatal real-time ultrasound.
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Abdomen↗
The diagnosis of absence of the corpus callosum by ultrasound.
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Agenesis of Corpus Callosum↗
A comparison of Pacific Islander and European stillbirths.
From 1967-1978, there were 26,688 births at St Helens Hospital, Auckland. A comparison was made between the Pacific Island stillbirths, and 65 matched European stillbirths. The stillbirth rate for the European group was only 6.6 per 1000 births, despite the increased prevalence of the following adverse factors: preterm 42 percent, toxaemia 38 percent, and lethal congenital abnormalities 20 percent. There was a significantly increased incidence of neural tube defects in the European group. In contrast the Pacific Island stillbirth rate was 11.1 per 1000 births, and the important factors were: unknown gestation 17 percent, post-term delivery 17 percent, no antenatal care 8 percent, or born before arrival in 3 percent. Intrauterine anoxia was the major cause of stillbirths, especially in the Pacific Island group where 68 percent of the infants were 37 weeks gestation or more. Community education stressing the importance of good antenatal care beginning in early pregnancy is needed for the Pacific Island mothers, with the avoidance of postmaturity and intrauterine anoxia by appropriate obstetric treatment.
Adult↗