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Biomedical subjects

H D McIntyre

Publications and source records attributed to H D McIntyre.

At least 19 recordsLinked to original sources

Fetal growth patterns in fetuses of women with pregestational diabetes mellitus.

OBJECTIVE: To assess the effect of glucose control on the rate of growth of fetuses in women with pregestational diabetes mellitus (Types 1 and 2). METHODS: All pregestational diabetic women booked at Mater Mothers' Hospital, Brisbane, Australia, between 1 January 1994 and 31 December 2002, were included. Pregnancies with congenital fetal anomalies, multiple pregnancies, and pregnancies terminated prior to 20 weeks' gestation were excluded. Dating scans were performed before 14 weeks' gestation and serial scans were performed at 18, 24, 28, 32 and 36 weeks. Fetal parameters, including biparietal diameter, femur length and abdominal circumference, were recorded. The daily growth rates for biparietal diameter, femur length, and fetal abdominal area were calculated and compared with those in a low-risk (non-diabetic) population. The growth rates in fetuses of women with satisfactory diabetic control (HbA1c < 6.5%) and unsatisfactory control (HbA1c > or = 6.5%) in the three trimesters were compared. RESULTS: A total of 174 diabetic pregnancies were included and a total of 997 ultrasound scans were performed. The growth rates for fetuses of mothers with diabetes mellitus were significantly higher than for those in the low-risk population. The z-scores for biparietal diameter, femur length, and fetal abdominal area were 0.18, 0.59 and 1.44, respectively. Fetuses of diabetic mothers with high HbA1c in the first trimester had significantly greater fetal abdominal area growth rate than those with normal HbA1c (fetal abdominal area z-score of 1.7 vs. 0.75, P = 0.009). Although the fetal abdominal area z-scores in fetuses of diabetic mothers with high HbA1c in the second or third trimesters were also higher than those with normal HbA1c levels, the differences did not reach statistical significance. Maternal obesity did not influence the fetal growth rate. CONCLUSION: The rate of growth of fetuses of diabetic mothers differs from that of the normal population. Growth acceleration persists until the late third trimester. Moreover, periconceptional glucose control appears to have a significant effect on accelerated growth of the fetal abdominal area.

Adult↗

Cardiac function in fetuses of poorly-controlled pre-gestational diabetic pregnancies--a pilot study.

OBJECTIVE: Cardiac impairment is frequently found in babies of diabetic mothers. It is still controversial whether this is due to poor glucose control. The aim of this study is to compare the cardiac function in fetuses of well- and poorly-controlled pre-gestational diabetic pregnancy in third trimester. METHODS: Women with type 1 pre-gestational diabetes were enrolled at 30-32 weeks. Cardiac size and interventricular septal wall thickness were measured by M-mode at end-diastolic phase. The right and left ventricular ejection fractions were calculated. At the mitral and tricuspid valves inflow, the ratio between early ventricular filling and active atrial filling (E/A) at both atrioventricular valves were measured by Doppler echocardiography. Peak velocities of ascending aorta and pulmonary artery were assessed. The angle of isonation was kept at <20 degrees. Women with poorly-controlled diabetes (HbA1c>6.5%) were compared with those with satisfactorily controlled diabetes (HbA1c < or = 6.5%). RESULTS: A total of 21 women with pre-gestational diabetes were recruited for this study. Eight women with well-controlled diabetes were compared with 9 women who had poorly-controlled diabetes. HbA1c in the poorly-controlled group was 7.3% and in the well-controlled group it was 5.4% (p<0.001). There was no difference between the two groups in cardiac size, interventricular septal wall thickness, ejection fraction, aorta and pulmonary artery peak flow velocities. The right atrioventricular E/A ratio was significantly lower among the poorly-controlled diabetic pregnancies (0.71 vs. 0.54; p<0.05). CONCLUSION: Fetuses of poorly-controlled diabetic mothers had a lower right atrioventricular E/A ratio. This may be due to metabolic acidosis, non-hypertrophic cardiac dysfunction or fetal polycythemia.

Diabetes Mellitus, Type 1↗

Routine ultrasound screening in diabetic pregnancies.

OBJECTIVES: To assess the detection rate of congenital fetal malformations and specific problems related to routine ultrasound screening in women with pre-existing diabetes. METHODS: A retrospective study was carried out to assess the performance of routine ultrasound screening in women with pre-existing diabetes (Types 1 and 2) within a tertiary institution. The incidence, type and risk factors for congenital fetal malformations were determined. The detection rate of fetal anomalies for diabetic women was compared with that for the low-risk population. Factors affecting these detection rates were evaluated. RESULTS: During the study period, 12 169 low-risk pregnant women and 130 women with pre-existing diabetes had routine ultrasound screening performed within the institution. A total of 10 major anomalies (7.7%) and three minor anomalies (2.3%) were present in the fetuses of the diabetic women. Central nervous system and cardiovascular system anomalies accounted for 60% of the major anomalies. Periconceptional hemoglobin A1c of more than 9% was associated with a high prevalence of major anomalies (143/1000). Women who had fetuses with major anomalies had a significantly higher incidence of obesity (78% vs. 37%; P < 0.05). Ultrasound examination of these diabetic pregnancies showed high incidences of suboptimal image quality (37%), incomplete examinations, and repeat examinations (17%). Compared to the 'low-risk' non-diabetic population from the same institution, the relative risk for a major congenital anomaly among the diabetic women was 5.9-fold higher (95% confidence interval, 2.9-11.9). The detection rate for major fetal anomalies was significantly lower for diabetic women (30% vs. 73%; P < 0.01), and the mean body mass index for the diabetic group was significantly higher (29 vs. 23 kg/m2; P < 0.001). CONCLUSION: The incidence of congenital anomalies is higher in diabetic pregnancies. Unfortunately, the detection rate for fetal anomalies by antenatal ultrasound scan was significantly worse than that for the low-risk population. This is likely to be related to the maternal body habitus and unsatisfactory examinations. Methods to overcome these difficulties are discussed.

Adult↗

Placental growth hormone is not suppressed by oral glucose loading in normal human pregnancy.

Placental growth hormone (PGH) progressively replaces pituitary growth hormone in the maternal circulation from mid-gestation onwards in human pregnancy. Our previous investigations have shown that placental growth hormone concentrations correlate well with foetal growth. Despite the apparent correlation between PGH and birthweight, the physiology of its secretion during pregnancy has not been well defined. We investigated the response of maternal serum PGH to oral glucose loading in pregnant women (n = 24) who demonstrated normal glucose tolerance at a mean gestation of 29 weeks. Mean (SEM) fasting PGH concentrations were high (36.9 [6.4] ng/ml). No suppression of PGH was noted at one, two or three hours after a 75 g oral glucose load. Similarly, no changes were noted in growth hormone binding protein or in calculated free PGH over the course of the glucose tolerance test. As expected, insulin concentrations rose sixfold and insulin like growth factor binding protein 1 concentrations fell by 20 % with glucose loading. Correlation analysis showed maternal weight, BMI, fasting serum glucose serum insulin to be significantly correlated with the babies' birthweight. Our results support the proposition that PGH concentrations in maternal serum are not suppressed by oral glucose loading in non-diabetic mothers.

Adult↗

Congenital thyrotoxicosis in premature infants.

OBJECTIVES: Graves' disease (GD) complicates 0.1% to 0.2% of pregnancies, but congenital thyrotoxicosis is rare occurring in one in 70 of these pregnancies independent of maternal disease status. Antenatal prediction of affected infants is imprecise; however, maternal history, coupled with a high maternal serum TSH receptor binding immunoglobulin index (TBII) predict adverse neonatal outcome. Mortality is reported to be as high as 25% in affected infants and would therefore be expected to be higher in premature infants. This study illustrates that in sick, premature, extreme low birth weight (ELBW) or intrauterine growth retarded (IUGR) infants, the diagnosis maybe overlooked especially in the absence of antenatal risk assessment and management of thyrotoxicosis in this setting is complex. DESIGN AND PATIENTS: The records of premature neonates born at the three main maternity units in Brisbane, between January 1996 and July 1998 diagnosed with congenital thyrotoxicosis were reviewed. Data were recorded on gestational age, birth weight (B Wt), maternal thyroid history and current status, and neonatal course. Thyroid function and TBII status was assessed using standard biochemical assays. RESULTS: Seven neonates from five pregnancies were identified (four female, three male). Mean gestational age was 30 week (25--36 week) and median B Wt was 1.96 kg (0.50--2.62 kg). Only one mother received formal antenatal counselling by a paediatric endocrine service and had a TBII (54%) measured prior to delivery. Three of five mothers had elevated TBII measured after diagnosis in their offspring (57%, 65%, 83%) and in one mother, a TBII was not performed. All mothers were biochemically euthyroid at delivery. Mean age at diagnosis was 9 days (1--16 days) and mean age at commencement of treatment was 12 days (7--26 days). Two infants received propylthiouracil and five received a combination of carbimazole and propranolol. Four became biochemically hypothyroid, in three this resolved with cessation of the antithyroid drug (ATD), and one required ongoing T4 supple-mentation. Only one infant required treatment for cardiac failure and there were no deaths in this cohort. CONCLUSIONS: This is a large series of extremely small and premature infants with neonatal thyro-toxicosis. Presentation was nonspecific. The diagnosis was delayed because of low birth weight, prematurity, multiple birth and/or an unrecognized maternal history of Graves' disease. The treatment of neonatal thyrotoxicosis was difficult in these extreme low birth weight infants yet no infant died and significant morbidity was confined to high output cardiac failure in one infant. With antenatal recognition of past or active Graves' disease, assessment of maternal TSH receptor binding immunoglobulin index prior to delivery and postnatal monitoring of cord TSH and venous fT4 and TSH on days 4 and 7 rapid treatment of affected infants may have further reduced neonatal morbidity.

Antithyroid Agents↗

Sonographic estimation of fetal weight in macrosomic fetuses: diabetic versus non-diabetic pregnancies.

The objective of this study is to compare the accuracy of sonographic estimation of fetal weight of macrosomic babies in diabetic vs non-diabetic pregnancies. All babies weighing 4,000 g or more at birth, and who had ultrasound scans performed within one week of delivery were included in this retrospective study Pregnancies with diabetes mellitus were compared to those without diabetes mellitus. The mean simple error (actual birthweight--estimated fetal weight); mean standardised absolute error (absolute value of simple error (g)/actual birthweight (kg)); and the percentage of estimated birthweight falling within 15% of the actual birthweight between the two groups were compared. There were 9,516 deliveries during the study period. Of this total 1,211 (12.7%) babies weighed 4,000 g or more. A total of 56 non-diabetic pregnancies and 19 diabetic pregnancies were compared. The average sonographic estimation of fetal weight in diabetic pregnancies was 8% less than the actual birthweight, compared to 0.2% in the non-diabetic group (p < 0.01). The estimated fetal weight was within 15% of the birthweight in 74% of the diabetic pregnancies, compared to 93% of the non-diabetic pregnancies (p < 0.05). In the diabetic group, 26.3 % of the birthweights were underestimated by more than 15 %, compared to 5.4% in the non-diabetic group (p < 0.05). In conclusion, the prediction accuracy of fetal weight estimation using standard formulae in macrosomic fetuses is significantly worse in diabetic pregnancies compared to non-diabetic pregnancies. When sonographic fetal weight estimation is used to influence the mode of delivery for diabetic women, a more conservative cut-off needs to be considered.

Abdomen↗

Placental growth hormone (GH), GH-binding protein, and insulin-like growth factor axis in normal, growth-retarded, and diabetic pregnancies: correlations with fetal growth.

We previously described significant changes in GH-binding protein (GHBP) in pathological human pregnancy. There was a substantial elevation of GHBP in cases ofnoninsulin-dependent diabetes mellitus and a reduction in insulin-dependent diabetes mellitus. GHBP has the potential to modulate the proportion of free placental GH (PGH) and hence the impact on the maternal GH/insulin-like growth factor I (IGF-I) axis, fetal growth, and maternal glycemic status. The present study was undertaken to investigate the relationship among glycemia, GHBP, and PGH during pregnancy and to assess the impact of GHBP on the concentration of free PGH. We have extended the analysis of specimens to include measurements of GHBP, PGH, IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), IGFBP-2, and IGFBP-3 and have related these to maternal characteristics, fetal growth, and glycemia. The simultaneous measurement of GHBP and PGH has for the first time allowed calculation of the free component of PGH and correlation of the free component to indexes of fetal growth and other endocrine markers. PGH, free PGH, IGF-I, and IGF-II were substantially decreased in IUGR at 28-30 weeks gestation (K28) and 36-38 weeks gestation (K36). The mean concentration (+/-SEM) of total PGH increased significantly from K28 to K36 (30.0 +/- 2.2 to 50.7 +/- 6.2 ng/mL; n = 40), as did the concentration of free PGH (23.4 +/- 2.3 to 43.7 +/- 6.0 ng/mL; n = 38). The mean percentage of free PGH was significantly less in IUGR than in normal subjects (67% vs. 79%; P < 0.01). Macrosomia was associated with an increase in these parameters that did not reach statistical significance. Multiple regression analysis revealed that PGH/IGF-I and IGFBP-3 account for 40% of the variance in birth weight. IGFBP-3 showed a significant correlation with IGF-I, IGF-II, and free and total PGH at K28 and K36. Noninsulin-dependent diabetes mellitus patients had a lower mean percentage of free PGH (65%; P < 0.01), and insulin-dependent diabetics had a higher mean percentage of free PGH (87%; P < 0.01) than normal subjects. Mean postprandial glucose at K28 correlated positively with PGH and free PGH (consistent with the hyperglycemic action of GH). GHBP correlated negatively with both postprandial and fasting glucose. Although GHBP correlated negatively with PGH (r = -0.52; P < .001), free PGH and total PGH correlated very closely (r = 0.98). The results are consistent with an inhibitory function for GHBP in vivo and support a critical role for placental GH and IGF-I in driving normal fetal growth.

Adult↗

Growth hormone-binding protein in normal and pathologic gestation: correlations with maternal diabetes and fetal growth.

To date, measurements of GH-binding protein (GHBP) during human pregnancy have been carried out using assays susceptible to interference by the elevated levels of human placental GH typical of late gestation. We recruited a large cohort of pregnant women (n = 140) for serial measurements of GHBP and used the ligand immunofunctional assay for GHBP. For normal gravidas, GHBP levels fell throughout gestation. Mean levels were 1.07 nmol/L (SE = 0.18) in the first trimester, 0.90 nmol/L (SE = 0.08) at 18-20 weeks, 0.73 nmol/L (SE = 0.05) at 28-30 weeks, and 0.62 nmol/L (SE = 0.06) at 36-38 weeks. GHBP levels in the first trimester correlated significantly with maternal body mass index (r = 0.58; P < 0.01). GHBP levels in pregnancies complicated by noninsulin-dependent diabetes mellitus (NIDDM) were substantially elevated at all gestational ages. The mean value in the first quarter (2.29 nmol/L) was more than double the normal mean (P < 0.01). In contrast, patients with insulin-dependent diabetes mellitus (IDDM) showed reduced GHBP concentrations at 36-38 weeks. The correlation between body mass index and GHBP is consistent with a metabolic role for GHBP during pregnancy, as is the dramatic elevation in GHBP observed in cases of NIDDM. At 36 weeks gestation, GHBP was significantly elevated (P < 0.01) in those women whose neonates had low birth weight (< 10th percentile). In early gestation (< 14 weeks), GHBP tended to be higher in women whose fetuses were designated to be at risk of intrauterine growth retardation (1.39 nmol/L; n = 4; compared with 1.07 nmol/L in normals), but this did not reach statistical significance. Although both NIDDM and IDDM pregnancies are at risk of fetal macrosomia, their GHBP concentrations are markedly divergent. This paradox and the roles of glucose and insulin in the regulation of GHBP during gestation warrant further investigation.

Carrier Proteins↗

A randomized trial comparing 1.25 mmol/l calcium dialysate to 1.75 mmol/l calcium dialysate in CAPD patients.

BACKGROUND: Effective control of hyperparathyroidism and renal osteodystrophy in CAPD patients requires a combination of calcitriol and calcium carbonate (CaCO3), but is frequently limited by hypercalcaemia. Reducing dialysate calcium (Ca) concentration may overcome this problem, but had not been examined in a controlled trial. METHODS: 45 stable CAPD patients were randomly assigned in a prospective double-blind trial to either a study group (1.25 mmol/l Ca dialysate) or a control group (1.75 mmol/l Ca dialysate) for 12 months. Clinical, biochemical and radiological parameters of secondary hyperparathyroidism were followed. RESULTS: Twenty-three patients did not complete the study due to death (9), transplantation (7) or conversion to haemodialysis (7). Eleven patients in each group completed the study. Mean serum Ca, phosphate, ionized Ca, aluminium, alkaline phosphatase (AP), and bone mineral density (BMD) Z-scores did not differ significantly at any time within or between the two groups. Severe hypercalcaemia was more common in the control group (11 vs. 2, P = 0.027). Mean serum intact parathyroid hormone (PTH) and osteocalcin (OCN) initially rose in the study group relative to controls at 3 months (40 +/- 7 vs 12 +/- 3 pmol/l, P = 0.004, and 33 +/- 5 vs 15 +/- 2 micrograms/l, P = 0.002 respectively), but were not sustained. Median weekly dosages of calcitriol and daily dosages of CaCO3 increased significantly in the study group (O microgram to 1 microgram P = 0.014 and 1260 mg to 2520 mg P = 0.002 respectively), but not in the control group. Supplementary aluminium hydroxide (A1, (OH)3) was required for phosphate control in both study (n = 5) and control patients (n = 4). CONCLUSIONS: Lowering dialysate calcium concentration reduced the frequency of severe hypercalcaemia and allowed prescription of larger quantities of calcitriol and CaCO3. However, in this study it offered no advantage in terms of A1(OH)3 requirement, while bone mass density did and may have initially exacerbated secondary hyperparathyroidism not change.

Aluminum Hydroxide↗

Measuring the systemic effects of inhaled beclomethasone: timed morning urine collections compared with 24 hour specimens.

BACKGROUND: Inhaled glucocorticoid therapy has systemic effects including hypothalamic-pituitary-adrenal (HPA) suppression. The optimal test for detecting these effects has not been defined. METHODS: Timed urine collections and 09.00 hour plasma cortisol levels were obtained from 12 normal volunteers receiving inhaled placebo, beclomethasone (BDP) 800 or 2000 micrograms/day. The 24 hour urine samples were collected as follows: first hour after waking (hour 1), the next two hours after waking (hours 2 and 3), remainder of day, and overnight, with results expressed as urine cortisol/creatinine (UCC) ratios and as hourly cortisol output in the timed collections. Twenty four hour urinary cortisol excretion was also calculated. Medication was blinded and given in random order with a washout period of at least 11 days between each treatment arm. RESULTS: None of the UCC ratios changed with BDP 800 micrograms/day. UCC ratios at hour 1, hour 2 and 3, and overnight, and 24 hour urinary free cortisol excretion were reduced after BDP 2000 micrograms/day, whilst remainder of day UCC ratio and the plasma cortisol level did not change significantly. Cortisol output showed similar changes. In a follow up study BDP 1400 micrograms/day also reduced UCC ratios for the first two hours after waking. CONCLUSIONS: UCC ratios are as sensitive as the more cumbersome 24 hour urinary free cortisol excretion, and more sensitive than single morning plasma cortisol measurements, in detecting the effects of inhaled beclomethasone on the HPA axis.

Administration, Inhalation↗

Long-term bone loss after renal transplantation: comparison of immunosuppressive regimens.

Serial measurements of serum and urine markers of bone metabolism and of forearm bone density (BMD) by dual photon absorptiometry were performed in 22 patients undergoing renal transplantation in 1986. Patients were randomised to immunosuppression with (1) cyclosporin alone (CsA group, n = 10), (2) cyclosporin for 3 months followed by azathioprine-prednisone (CsA/AzP group, n = 3) or (3) long-term azathioprine-prednisone (LT AzP group, n = 9). As no reduction in bone mineral density (BMD) was noted in the first 6 months, groups 2 and 3 were considered together (AzP group, n = 12). Mean +/- SEM BMD fell by 19 +/- 2% at 36 months (n = 19, p < 0.01), with similar reductions seen in the CsA and AzP groups. At 60 months, BMD of the AzP group was 25 +/- 3% below baseline (p < 0.01), while the CsA group were only 5 +/- 4% below baseline (p = NS vs baseline, p < 0.05 vs AzP group). The degree of reduction in BMD over 5 years correlated with total glucocorticoid dose (r = 0.63, p < 0.05), but not with biochemical markers of bone turnover. Serum alkaline phosphatase fell post-transplant in patients treated with AzP, but not in the CsA group. These results demonstrate significant loss of forearm bone mineral with long-term follow-up after renal transplantation, but suggest that patients treated with cyclosporin monotherapy may be at lower risk of this complication.

Absorptiometry, Photon↗

Intrahepatic cholestasis of pregnancy, worsening after dexamethasone.

We present a case of intrahepatic cholestasis of pregnancy (ICP) treated with dexamethasone. Rapid elevation in transaminases was observed, beyond levels usually reported in this condition. The world literature is reviewed, with particular reference to a recently suggested treatment protocol using dexamethasone.

Adult↗

The effect of nasal hCT on bone turnover in Paget's disease of bone--implications for the treatment of other metabolic bone diseases.

Thirty pagetic patients were treated for 6 months with a daily nasal application of 2 mg of synthetic human calcitonin (hCT). Serum alkaline phosphatases (SAP) and urinary hydroxyproline/creatinine ratio (OH/Cr), reflecting bone turnover, were significantly reduced from the first month of treatment (mean +/- SEM: SAP, -13.9 +/- 2.2%; OH/Cr, -22.2 +/- 5.8%; both P less than 0.01) and until the end of the 6-month course (mean +/- SEM: SAP, -29.7 +/- 4.6%; OH/Cr, -22.5 +/- 5.9%; both P less than 0.01). Nasal hCT was perfectly tolerated both locally and systemically. These results allow us to consider nasal hCT for long-term trials in metabolic bone diseases characterized by a relative increase of bone resorption.

Administration, Intranasal↗

Immunoreactive somatostatin in the rat ovary.

Immunoreactive SRIH was detected in the rat ovary (15.6 pg/mg wet weight, 520 pg/mg protein) and was localized to the granulosa cells (168 +/- 6 pg/10(6) cells). Serial dilution studies showed parallelism of the inhibition curve for synthetic SRIH-14 and those of extracts of whole ovary and media conditioned by granulosa cells. The quantity of immunoreactive SRIH released into granulosa cell conditioned media decreased with time, while the intracellular content remained relatively constant. Gel chromatography showed peaks of immunoreactivity co-eluting with SRIH-14 (38%), SRIH-28 (31%) and a high molecular weight component. The addition of synthetic SRIH-14 stimulated meiotic maturation in cumulus-enclosed rat oocytes, with dose dependency being observed at SRIH-14 concentrations between 1 and 1000 pmol/l. No evidence of pre-pro-SRIH gene expression could be demonstrated in either rat ovary or testis using both Northern analysis and reverse transcriptase/polymerase chain reaction amplification of polyadenylated RNA. SRIH may be produced in the ovary during a specific stage of ontogeny or by an alternative gene. It is also possible that SRIH is actively taken up and stored by granulosa cells without being produced locally.

Animals↗

Chronic sulfonylurea therapy augments basal and meal-stimulated insulin secretion while attenuating insulin responses to sulfonylurea per se.

OBJECTIVE: To examine changes in glycemia and insulin secretion in response to SU per se and in response to a standard diet plus OD or TD SU therapy during chronic GP and GB therapy. RESEARCH DESIGN AND METHODS: Randomized (between agents and in order of dosing regimens), prospective, open, crossover study among 14 NIDDM patients to compare glucose, insulin, and C-peptide responses to a standard diet and to 10 mg of oral GP or GB taken without food 1) after 2 wk without therapy, 2) after 4 wk of either GP (n = 7) or GB (n = 7) treatment OD, and 3) after 4 wk of TD therapy with the same agent. Each patient received the same drug for maintenance therapy and for assessment of the response to the drug alone. RESULTS: We observed a comparable reduction in overall glycemia with both agents, with more marked postprandial effects for GP. Similar glucose, insulin, and C-peptide profiles for both agents during OD and TD therapy. Augmented insulin secretion in response to meals contrasting with reduced insulinotropic effects of the drugs per se with chronic therapy. CONCLUSIONS: Therapeutic equivalence of OD and TD dosing with GP and GB during chronic therapy. In view of the improved insulin secretion in response to nutrient stimuli, the attenuation of responses to SU per se during chronic therapy does not imply impairment of beta-cell secretory capacity or represent a therapeutic disadvantage.

Adult↗