Biomedical subjects

J S Robinson

Publications and source records attributed to J S Robinson.

At least 19 recordsLinked to original sources

PubMed1999

Women's role and satisfaction in the decision to have a caesarean section.

OBJECTIVE: To examine women's role in the decision to perform caesarean section (CS). DESIGN: Cross-sectional survey. Written questionnaires were completed seven weeks after giving birth by CS. SETTING: An obstetric tertiary referral hospital (Women's and Children's Hospital, Adelaide, South Australia), July to December 1996. PARTICIPANTS: A consecutive sample of women who underwent CS over a six-month period. To be eligible, women had to be at least 18 years old, able to complete a questionnaire in English and well enough to consent to study participation. MAIN OUTCOME MEASURES: Women's involvement in decision making, stated preference for CS, and satisfaction with obstetric care. RESULTS: 278 women (76.4%) returned questionnaires: 171 women (61.5%; 95% confidence interval [CI], 55.8%-67.2%) reported being involved in the decision to have a CS. Factors influencing their decision were physical duress and partner's reaction during labour (emergency CS), considerations about recovery, planning for the event and pain (elective CS), and information from the doctor (both groups). Half the women "strongly agreed" that they were satisfied with the decision to have a CS, but 40.9% only "agreed" and 4.7% were "not sure". About 20% reported they needed more information on other options, and only 28.8% "strongly agreed" that they had been given good information to prepare for the possibility of CS. 27.9% of women (95% CI, 22.5%-33.2%) "agreed" or "strongly agreed" that they had "insisted on a CS" and 21.3% (95% CI, 16.4%-26.2%) that they had told the staff they were "keen to have a CS". Given the option of a vaginal delivery, 37.8% of women (95% CI, 22.5%-55.2%) with a breech presentation, and 34% of women (95% CI, 21.2%-48.8%) who had had a previous CS, chose a CS. CONCLUSIONS: It is of concern that over a third of women felt they had not been involved in the decision to have a CS; others were very positive about CS, but an appreciable proportion may not have received sufficient information. A broad-based strategy of providing more information to women and their partners could be one way of ensuring appropriate CS rates and should be tested in a randomised controlled trial.

Adult↗

PubMed1999

Restriction of placental and fetal growth in sheep alters fetal blood pressure responses to angiotensin II and captopril.

1. We have measured arterial blood pressure between 115 and 145 days gestation in normally grown fetal sheep (control group; n = 16) and in fetal sheep in which growth was restricted by experimental restriction of placental growth and development (PR group; n = 13). There was no significant difference in the mean gestational arterial blood pressure between the PR (42.7 +/- 2.6 mmHg) and control groups (37.7 +/- 2.3 mmHg). Mean arterial blood pressure and arterial PO2 were significantly correlated in control animals (r = 0.53, P < 0.05, n = 16), but not in the PR group. 2. There were no changes in mean arterial blood pressure in either the PR or control groups in response to captopril (7.5 microg captopril min-1; PR group n = 7, control group n = 6) between 115 and 125 days gestation. After 135 days gestation, there was a significant decrease (P < 0.05) in the fetal arterial blood pressure in the PR group but not in the control group during the captopril infusion (15 microg captopril min-1; PR group n = 7, control group n = 6). 3. There was a significant effect (F = 14.75; P < 0.001) of increasing doses of angiotensin II on fetal diastolic blood pressure in the PR and control groups. The effects of angiotensin II were different (F = 8.67; P < 0.05) in the PR and control groups at both gestational age ranges. 4. These data indicate that arterial blood pressure may be maintained by different mechanisms in growth restricted fetuses and normally grown counterparts and suggests a role for the fetal renin-angiotensin system in the maintenance of blood pressure in growth restricted fetuses.

Angiotensin II↗

PubMed1999

Reduced foetal growth and growth hormone secretion in adult life.

OBJECTIVES: Recent studies suggest that growth restriction or other adverse influences acting in utero or during early infancy lead to permanent alterations in growth hormone (GH) secretion. As GH secretion is known to predict cardiovascular risk, alterations in GH may contribute to the association between reduced foetal growth and cardiovascular disease. We have therefore assessed the relationship between birth size and GH secretion in a prospective study of young adults whose birth size was recorded and who have had their current blood pressure and glucose tolerance measured. DESIGN: Prospective cohort study PATIENTS: 153 healthy men and women, aged 20-21 years. MEASUREMENTS: Subjects carried out a timed overnight urinary collection for analysis of GH excretion. Insulin sensitivity and insulin secretion were measured using the intravenous glucose tolerance test with minimal model analysis. Blood pressure, height, weight, usual level of exercise, smoking habits, alcohol consumption, and socio-economic status were also recorded. RESULTS: GH excretion ranged from 0.01 to 41.8 microU per subject. It did not differ according to gender but was markedly reduced in obese subjects (P < 0.0001) Low birthweight was strongly associated with low GH excretion at age 20 years (P = 0.002). Low placental weight and short body length also predicted low GH (P = 0.02 and P = 0.04, respectively). These relationships were independent of other confounding factors including obesity. GH excretion was not independently related to current levels of blood pressure, insulin sensitivity or insulin secretion. CONCLUSIONS: Body size at birth predicts GH excretion in adult life. Low GH excretion in people who were small at birth may be one mechanism explaining their increased risk of cardiovascular disease.

Adult↗

PubMed1999

The relationship between birth weight and blood pressure amplifies from childhood to adulthood.

OBJECTIVE: To investigate relationships between birth characteristics and blood pressure at age 20 years and to assess whether effects of birth weight on blood pressure are amplified from childhood to adulthood. DESIGN: A longitudinal study of 584 men and women from Adelaide, Australia, examined previously at 8 years and followed up at age 20 years. RESULTS: Birth weight was negatively associated with systolic pressure at age 20 years in men (regression coefficient 2.6 mmHg per kg; 95% confidence interval 0.7, 4.4) and women (regression coefficient 4.6 mmHg per kg; 95% confidence interval 2.9, 6.4), after adjustment for current weight There was an interaction with current size (P = 0.05 for men and P = 0.09 for women), such that effects were enhanced among individuals with relatively high weight or weight for height. Shortness at birth, thinness at birth, and low birth weight relative to placental weight were also associated with elevated systolic pressure at age 20 years. Effects of birth weight on blood pressure were stronger at age 20 than at age 8 years (P < 0.01 for men and P = 0.03 for women). This was not due simply to increased variability of blood pressure in adulthood. There were greater rises in blood pressure with age among individuals of relatively low birth weight. CONCLUSIONS: These findings are further evidence that poor fetal growth is associated with elevated blood pressure in later life. The results support the hypothesis that the relationship is amplified with increasing age.

Adolescent↗

PubMed1999

Calcium supplementation in nulliparous women for the prevention of pregnancy-induced hypertension, preeclampsia and preterm birth: an Australian randomized trial. FRACOG and the ACT Study Group.

A multicentre, randomized controlled double-blind trial in 5 maternity hospitals in Australia assessed the effect of a daily supplement of calcium (1.8g oral calcium or an oral placebo) taken daily until delivery, from less than 24 weeks' gestation, on the frequency of pregnancy-induced hypertension, preeclampsia and preterm birth (< 37 weeks' gestation) in 456 nulliparas with a singleton pregnancy. Treatment with calcium reduced the risk of preeclampsia (relative risk 0.44 [95% CI, 0.21-0.90], p = 0.02) and the risk of preterm birth (relative risk 0.44 [95% CI, 0.21-0.90], p = 0.02). No significant differences were seen between the 2 groups in the frequency of pregnancy-induced hypertension, although the study only had statistical power to detect large differences in this outcome. An updated systematic review of the 9 randomized trials of calcium supplementation in pregnancy shows a significant reduction in the risk of hypertension and preeclampsia although no effect on preterm birth. Calcium supplementation during pregnancy reduced the risk of preeclampsia and preterm birth in this nulliparous population. The available evidence for systematic review of all the randomized trials of calcium supplementation shows benefit in reducing the risk of hypertension and preeclampsia.

Adult↗

PubMed1999

The autonomic control of heart rate and insulin resistance in young adults.

The pathophysiology of insulin resistance is unclear. A link between increased heart rate (HR) and insulin resistance suggests an association with sympathetic nervous system activity. To further evaluate this, we examined autonomic activity using spectral analysis of HR variability (HRV), which provides a measure of cardiac sympathovagal modulation, and related this to insulin sensitivity (Si) in 137 men and women (20 yr old). The HRV spectrum displays 2 major peaks: a high-frequency peak, reflecting vagal activity, and a low-frequency peak caused by vagal and sympathetic activity. The high-to-low ratio (HLratio) reflects sympathovagal balance. Si was measured, using the i.v. glucose tolerance test with minimal modeling, and HR data was derived from a 15-min supine electrocardiogram. Women were more insulin resistant than men (Si, 3.94 vs. 5.09 10(4) min(-1)/per pmol x L; P = 0.002), had higher HR (59 vs. 56 beats/min, P = 0.019), but had a higher HLratio (2.04 vs. 1.31, P = 0.001). In men (but not women), Si correlated with HR (r = -0.410, P = 0.001) and measures of HRV: HLratio (r = 0.291, P = 0.002) independently of body mass index. In conclusion, Si correlates with cardiac sympathovagal balance in men, but not women, suggesting gender differences in the autonomic modulation of insulin resistance.

Adult↗

PubMed1998

Cervical spinal cord--smaller than considered?

STUDY DESIGN: One hundred two patients with symptoms of cervical radiculopathy, were retrospectively analyzed and their cervical spinal cord diameters obtained. OBJECTIVES: To measure the cervical spinal cord in vivo and to compare the findings with those previously reported in the literature. SUMMARY OF BACKGROUND DATA: Traditionally, autopsy data have served as the linchpin of cervical cord measurements. However, several studies obtained by realtime radiographic methods have failed to confirm such measurements. METHODS: The spinal cord was retrospectively measured in 102 patients. All patients underwent myelogram and postmyelogram computed tomographic scan. Anteroposterior and transverse diameters of the spinal cord were measured from C2 to T1 at the level of each intervertebral disc. The depth of the anterior median fissure and cross-sectional area were measured as well. Plain myelographic films were reviewed but demonstrated no findings contrary to postmyelogram computed tomographic measurements. RESULTS: There was no statistically significant difference in the spinal cord measurements in relation to age or sex. There was an increase in the transverse diameter but not in the anteroposterior diameter in the midcervical spinal enlargement. The anteroposterior diameter decreased linearly. The transverse diameter and the cross-sectional area increased to a maximum at C5, as did the depth of the anterior median fissure. The cervical spinal cord diameter was documented to be 15-20% smaller than has commonly been determined by autopsy data. CONCLUSIONS: Postmyelogram computed tomographic measurements are smaller than those obtained from autopsy data.

Adult↗

PubMed1998

'Out-of-hospital cardiac arrests' treated by the West Midlands Ambulance Service over a 2-year period.

We aimed to determine whether our results were any better or worse than other published reports and to examine the efficacy of the West Midlands Ambulance Service (WMAS) policy of applying cardiopulmonary resuscitation (CPR) and manual ventilation to all unwitnessed cardiac arrests in preference to immediate defibrillation. All cardiac arrests were studied from October 1994 to September 1996. In all unwitnessed arrests, crews undertook CPR and manually ventilated the lungs via a mask or an endotracheal tube with a bag and valve or a mechanical resuscitator using an FIO2 of 1 or 0.21 for at least 2 min before defibrillation was attempted. There were 3403 diagnosed cardiac arrests but, in these, the diagnosis was not certain. CPR and advanced life support (ALS) were applied in 3380 patients and return of spontaneous circulation (ROSC) was obtained in 554, giving a success rate of 16.4%. A total of 364 patients were accepted into hospital, 90 patients died in A&E but 274 patients were admitted to ICU/CCU. Seventy died within 24 h, 69 died after 24 h and 135 were discharged alive and well without cerebral damage. The final success to discharge rate was 49.27%. Of those discharged, 69 had a circulatory arrest period of more than 4 min but in only 10 was a bystander available to start CPR. The European Resuscitation Council Guidelines recommending immediate defibrillation for unwitnessed arrests are not supported by these results. The apparent lack of cerebral damage and the percentage success suggests that resuscitation considerations should be as brain orientated as they are heart orientated. The elapsed time periods reported challenge several shibboleths.

Brain Damage, Chronic↗

PubMed1998

Food restriction alters pregnancy-associated changes in IGF and IGFBP in the guinea pig.

The effect of moderate food restriction on pregnancy-associated changes in weight gain, body composition, and circulating insulin-like growth factors (IGF) I and II and IGF-binding proteins (IGFBP)-1 through-4 and their relationship was determined in the guinea pig. Pregnancy did not stimulate weight gain but reduced fat deposition in ad libitum-fed animals and increased weight gain and fat deposition in food-restricted animals relative to their respective virginal group. Pregnancy increased the abundance of circulating IGF-I regardless of food intake and increased that of IGF-II in food-restricted animals only. Pregnancy also increased circulating IGFBP-1 and -2 in ad libitum-fed and food-restricted animals and IGFBP-4 in ad libitum-fed animals. Multiple regression analysis showed that maternal weight gain was negatively associated with circulating IGF-II and IGFBP-2. Fetal weight was positively associated with maternal circulating IGF-II and negatively associated with maternal circulating IGFBP-1 and -2. Significant interactions indicate, however, that the role of IGF-II and IGFBP-1 on fetal growth is dependent on the nutritional status of the mother.

Animals↗

PubMed1998

Results and complications from the use of a frameless stereotactic microscopic navigator system.

We present a series of 21 patients, 12 males and 9 females, aged 41-76 years, with the preoperative diagnosis of a brain tumor. Both preoperatively and postoperatively, all of our patients underwent either a brain computed tomography (CT) or magnetic resonance imaging (MRI). All the radiographic studies were taped and loaded preoperatively in the Stereotactic Microscopic Navigator (SMN) workstation (Zeiss, Germany). The mean duration of this procedure was 25 +/- 6 min. All our patients were operated on in our institute with the use of the SMN system. The specificity of tumor localization using CT scan was 2.20 +/- 0.25 mm and for the MRI scan 2.6 +/- 0.25 mm. As assessed by postoperative radiographic studies, total gross tumor resection was possible in 20 patients (95.23%). No major intraoperative or early postoperative complications were noted in our series. We believe that the SMN system is a safe, well-tolerated by the patients and simple method with extremely high accuracy and specificity.

Aged↗

PubMed1998

Placental restriction alters adrenal medullary development in the midgestation sheep fetus.

The aims of this study were to determine whether placental restriction (PR) alters the pattern of localization of the catecholamine-synthesizing enzymes, dopamine-beta-hydroxylase and phenylethanolamine N-methyltransferase, and enkephalin (ENK)-containing peptides in the adrenal gland of the midgestation sheep fetus. We also determined the effect of PR on the content and profile of the molecular mass forms of ENK-containing peptides in the fetal adrenal medulla. Placental growth was restricted by removal of most of the placental implantation sites in the uterus before mating. In midgestation, placental and fetal body weight were reduced (p < 0.05) in the PR group (n = 8; 237.9 +/- 39.5 g, 564.7 +/- 41.6 g, respectively) when compared with the control group (n = 9; 479.1 +/- 36.9 g, 721.2 +/- 22.8 g, respectively). However, combined fetal adrenal weight and adrenal cortical and medullary area were similar in the PR and control fetuses. In PR fetuses, distribution of staining for dopamine-beta-hydroxylase, phenylethanolamine N-methyltransferase, and ENK-containing peptides in the adrenal medulla was similar when compared with the control group; however, staining was less intense and not all adrenomedullary cells were stained. The total adrenal content of ENK-containing peptides was also significantly (p < 0.05) less in the PR group (103.4 +/- 18.6 ng/adrenal) than in the control group (243.6 +/- 24.8 ng/adrenal). However, the molecular mass profile of ENK-containing peptides was not altered in the PR fetuses compared with controls. These data suggest that placental restriction in utero may alter the synthesis and/or secretion of catecholamines and ENK-containing peptides from the fetal adrenal medulla from as early as 90 d gestation.

Adrenal Medulla↗

PubMed1998

Effects of acute and chronic food restriction on the insulin-like growth factor axis in the guinea pig.

The effect of fasting (17-18 h) versus food restriction (70% for 80 +/- 13 days) on the IGF-IGF binding protein (BP) axis in female guinea pigs was studied and related to body weight, weight gain and food conversion efficiency. Circulating IGF-I was reduced in the fasted (13%) and food-restricted (50%) animals. IGF-II was only decreased (61%) in the food-restricted group. There was no effect of fasting on IGFBP-1 to -4 while IGFBP-1, -3 and -4 were reduced by 56%, 60% and 44% respectively, and IGFBP-2 increased by 72%, in the food-restricted group. Food restriction reduced the relative sizes of fat depots, spleen, liver, thymus and heart, increased those of adrenals, kidneys, pancreas, gastrointestinal tract, M. Biceps, M. Soleus and brain while those of uterus, lungs, thyroids and M. Gastrocnemius were unchanged. IGFBP-1 and -2 were negatively correlated to weight gain and food conversion efficiency in the ad libitum-fed group, while IGF-I, -II, IGFBP-1, -3 and -4 were positively correlated to body weight, weight gain and food conversion efficiency in the food-restricted group. The results show that acute and chronic food restriction have different consequences for the IGF-IGFBP axis. Furthermore, IGF-II as well as IGF-I are implicated in the control of body weight, weight gain and food conversion efficiency under conditions of restricted nutrition. Finally, IGFBP-1 and -2 may have different roles during chronic undernutrition compared with unrestrained nutrition in adult life.

Animals↗

PubMed1997

Restriction of nutrition in utero selectively inhibits gastrointestinal growth in fetal sheep.

This study examined the effects of reduced nutrition on fetal growth over the first half of gestation. Reduced nutrition was achieved by a combination of reduced maternal food intake and carunclectomy, a procedure which restricts the development of the placenta. There were no major effects of restriction on fetal body, tissue or organ growth, except for the gastrointestinal tract (GIT). Total GIT weight was lower in restricted fetuses than in controls. More specifically, it was growth of the small and large intestine which was compromised. Small intestinal weight was significantly lower, both in absolute terms and relative to body weight. The intestinal diameter and mucosal area were significantly lower in both small and large intestine of restricted fetuses. Maturation of enterocytes was also delayed in nutrient-restricted fetuses. In addition, there were focal lesions of the brush border present, indicating abnormal epithelial differentiation. By term, in growth-retarded fetuses, growth deficits in many organs were present, including the GIT. The present study suggests that GIT growth deficits may have a long-term etiology, including at their onset, abnormal cellular differentiation. These results could explain why GIT function in intrauterine growth-retarded infants is more likely to be compromised than in premature or term infants.

Animal Nutritional Physiological Phenomena↗

PubMed1997

Early influences on embryonic and placental growth.

Growth of the placenta is influenced by events before and during early pregnancy. Some of these events set the growth trajectory of the placenta and the fetus for the remainder of the pregnancy. Maternal size and nutrition, and the local metabolic, cytokine and hormonal environment of the embryo all affect growth of the placenta.

Animals↗

PubMed1997

Impact of placental restriction on the development of the sympathoadrenal system.

We have investigated the impact of chronic restriction of placental function on circulating catecholamine concentrations and responses to the indirectly acting, sympathomimetic amine, tyramine, in the fetal sheep in late gestation. In 10 ewes, endometrial caruncles or placental placentation sites were removed before conception (placental restriction (PR) group). Fetal sheep in the PR group were hypoxemic throughout late gestation and growth-restricted (3.02 +/- 0.35 kg) when compared with control fetal sheep (4.30 +/- 0.29 kg; n = 8) at 140 d of gestation. Fetal plasma concentrations of noradrenaline and adrenaline were higher (p < 0.05) in the PR (7.06 +/- 3.17 pmol/mL and 2.89 +/- 2.01 pmol/mL, respectively) than in the control group (3.55 +/- 0.54 pmol/mL and 1.30 +/- 0.48 pmol/mL, respectively) throughout late gestation. Plasma noradrenaline, but not adrenaline concentrations, increased significantly between 110 and 140 d of gestation in both the PR and control group, and there was a significant inverse relationship between plasma noradrenaline and arterial PO2 in the PR and control groups (plasma noradrenaline = 12.34 - 0.40 PO2). In the PR group, plasma noradrenaline increased (p < 0.05) after tyramine infusion from 4.51 +/- 1.28 pmol/mL to a peak of 19.40 +/- 3.56 pmol/mL. In the control group, noradrenaline increased from 2.08 +/- 0.30 pmol/mL to a peak of 12.23 +/- 1.67 pmol/mL after tyramine infusion. There was no difference, however, in the maximal proportional changes in plasma noradrenaline concentrations in the PR (319 +/- 55%) and control (449 +/- 100%) groups after tyramine. We conclude that the most likely source of the increased plasma catecholamines in the PR group is enhanced catecholamine synthesis and secretion from developing sympathetic neurons.

Adrenal Glands↗

PubMed1997

Australian Collaborative Trial of Antenatal Thyrotropin-Releasing Hormone: adverse effects at 12-month follow-up. ACTOBAT Study Group.

OBJECTIVE: The Australian Collaborative Trial of Antenatal Thyrotropin-Releasing Hormone (ACTOBAT) assessed the efficacy of 200 microg of thyrotropin-releasing hormone (TRH) in combination with glucocorticoids in the prevention of neonatal lung disease. This paper reports the 12-month follow-up of the infants from the trial completed in 1994. DESIGN: This was a double-blinded randomized controlled trial. SETTING: Women were recruited from level 3 perinatal centers throughout Australia. PARTICIPANTS: Mothers who had not withdrawn from treatment and whose infants were discharged alive (1262 infants). Extensive efforts were made to trace this entire cohort. OUTCOME MEASURES: A questionnaire was mailed to parents for self-completion immediately before their baby's/babies' first birthday. The questionnaire included a checklist to assess sensory, motor, language, and social development, and use of health services. RESULTS: Milestone scores were developed from items on the follow-up form. Treatment with TRH was associated with an increased risk of motor delay, social delay, fine motor delay, sensory impairment, and early language impairment. No differences were seen between treatment and placebo groups for motor impairment. Multivariate analyses were performed, adjusting for chronological age, duration of gestation at randomization, time from randomization to delivery, parity, history of perinatal death, history of preterm rupture of the membranes, infant sex, singleton or twin status, maternal age, and maternal blood pressure (systolic and diastolic) at randomization. For the total cohort (N = 1022), treatment with TRH was associated with motor delay (odds ratio [OR], 1.51; 95% confidence interval [CI] 1.11 to 2.05); social delay (OR 1.40; 95% CI 1.01 to 1.95); sensory impairment (OR, 2.00; 95% CI 1.06 to 3.74); severe impairment (OR, 1.75; 95% CI 1.07 to 2.87); and a trend toward motor impairment (OR, 1.50; 95% CI .97 to 2.33), early language impairment (OR, 1.27, 95% CI .90 to 1.79), and fine motor delay (OR, 1.15; 95% CI .83 to 1.60). There were no differences between the treatment groups in hospital admissions (OR, 1.08; 95% CI .83 to 1.42), doctors' visits (general practitioner OR adj, 1.09; 95% CI .79 to 1.50 or specialist OR adj 1.15; 95% CI .87 to 1.49), respiratory symptoms (OR adj, 1.16; 95% CI .88 to 1.53), or behavioral disturbances (OR adj, .93; 95% CI .71 to 1.21). CONCLUSIONS: Because antenatal administration of TRH is associated with small, consistent deficits in major milestone achievements at 12 months of age, it is essential that additional planned trials make provision for long-term follow-up. Antenatal TRH should only be used in the context of a clinical trial.

Adult↗

PubMed1996

Placental weight, birth measurements, and blood pressure at age 8 years.

OBJECTIVE: To examine relationships between blood pressure during childhood and both placental weight and body size at birth, in an Australian population. DESIGN: A follow up study of a birth cohort, undertaken when cohort members were aged 8 years. SETTING: Adelaide, South Australia. SUBJECTS: 830 children born in the Queen Victoria Hospital in Adelaide, South Australia, during 1975-6. MAIN OUTCOME MEASURES: Systolic and diastolic blood pressure measured when the children were aged 8 years. RESULTS: Blood pressure at 8 years was positively related to placental weight and inversely related to birth weight, after adjusting for the child's current weight. For diastolic pressure there was a decrease of 1.0 mm Hg for each 1 kg increase in birth weight (95% confidence interval (CI) = -0.4 to 2.4) and an increase of 0.7 mm Hg for each 100 g increase in placental weight (95% CI = 0.1 to 1.3). Diastolic pressure was also inversely related to chest circumference at birth, independently of placental weight, with a decrease of 0.3 mm Hg for each 1 cm increase in chest circumference (95% CI = 0.2 to 0.5). CONCLUSIONS: These findings are further evidence that birth characteristics, indicative of fetal growth patterns, are related to blood pressure in later life.

Anthropometry↗

PubMed1996

Insulin-like growth factor I promotes growth selectively in fetal sheep in late gestation.

Insulin-like growth factor I (IGF-I) is required for normal fetal growth and skeletal maturation in late gestation, because null mutations of the IGF-I gene in mice reduce fetal weight and retard ossification of bones. To determine if, conversely, increased abundance of IGF-I promotes fetal growth and skeletal maturation, fetal sheep were infused intravascularly with recombinant human IGF-I (n = 7) (26 +/- 3 micrograms. h-1.kg-1) from 120 to 130 days gestation and compared with controls (n = 15). IGF-I infusion increased plasma IGF-I concentrations by 140% (P = 0.002) and weights of fetal liver, lungs, heart, kidneys, spleen, pituitary, and adrenal glands by 16-50% (P < 0.05). Weights and/or lengths of the fetus, placenta, gastrointestinal tract, individual skeletal muscles, and long bones were unchanged by IGF-I. However, IGF-I increased the percentage of proximal epiphyses of long bones present (P < 0.05) and their cross-sectional areas by 15 to 38% (P < 0.05). These results show that IGF-I promotes growth of major fetal organs, endocrine glands, and skeletal maturation in vivo, consistent with IGF-I actively controlling and not merely facilitating fetal growth. The variable response of different tissues may partly reflect tissue specificity in growth requirements for additional factors.

Animals↗