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Biomedical subjects

C Chantler

Publications and source records attributed to C Chantler.

At least 109 records · Page 6Linked to original sources
PubMed1983

Sodium homeostasis in term and preterm neonates. II. Gastrointestinal aspects.

Eighty five 24 hour balance studies were performed on 70 healthy newborn infants of gestational age 27-40 weeks; dietary intake and stool losses of sodium were measured. There was a relation between gastrointestinal sodium absorption and conceptional age (the sum of gestational and postnatal age), whether expressed as absolute stool sodium losses or as the ratio of stool sodium to dietary sodium intake. The stool K:Na ratio rose appreciably with maturation, although stool content of potassium was not greatly increased. These findings suggest that intestinal sodium absorption is inefficient in immature babies and that the degree of malabsorption is inversely related to conceptional age.

Aging↗
PubMed1983

Metabolism of orally administered branched-chain alpha-keto acids.

The changes in serum branched-chain alpha-keto acid (BCKA) and plasma amino acid concentrations, in response to a therapeutic oral dose of an essential amino acid/keto acid mixture, were studied in fasting healthy adults. Of the branched-chain amino acids (BCAA), only the plasma leucine concentration rose significantly despite increases in al three serum BCKA concentrations. The plasma valine concentration tended to rise, but plasma isoleucine concentrations fell. When KMVA (keto-isoleucine) alone was given, there followed an increase in plasma isoleucine concentration and a fall in valine and leucine. Similarly, when KIVA (keto-valine) was given, plasma valine rose and leucine and isoleucine fell. These results suggest some transamination of the keto acid with amino groups of the other BCAA. KICA (keto-leucine), however, produced larger falls in plasma valine and isoleucine than was expected from the rise in leucine. In addition, KICA caused significant, insulin-independent reductions in plasma threonine, serine, cystine, methionine, tyrosine, phenylalanine, and alanine. We conclude that although orally administered BCKA's will increase the BCAA supply, their value may not simply relate to the supply of essential amino acids for protein synthesis but to a direct effect of KICA on protein metabolism.

Administration, Oral↗
PubMed1983

Glucose intolerance in children with chronic renal failure.

Carbohydrate metabolism was studied by the hyperglycemic clamp technique in 14 children with moderate to severe chronic renal failure (CRF) (8 pubertal and 6 prepubertal) and was compared with 5 healthy prepubertal children and 7 healthy young adults. Constant hyperglycemia was maintained for 120 min. Under these conditions, the average glucose infusion rate (M) is an index of glucose metabolic rate, the average insulin response (I) is an index of beta cell responsiveness to hyperglycemia, and the M/I ratio is an index of insulin sensitivity. Children with CRF were glucose intolerant (lower M), hyperinsulinemic (higher I), and insulin resistant (lower M/I) compared with the control children. An age-related difference in glucose tolerance and insulin sensitivity was noted. Pubertal children with CRF had lower M and lower M/I compared with prepubertal children with CRF. The 7 adult controls also had lower M and lower M/I compared with the 5 children controls. M and M/I correlated with glomerular filtration rate (GFR) in the 8 pubertal children, while M/I also correlated with GFR in the 6 prepubertal children with CRF. The hyperglycemic clamp provides a useful tool in studying the pathogenesis of carbohydrate disturbances in children with CRF.

Adolescent↗
PubMed1983

Secondary hyperparathyroidism and glucose intolerance in children with uremia.

Glucose metabolism was studied using the glucose clamp technique in 8 children with CRF (4 pubertal and 4 prepubertal) before and after correction of secondary hyperparathyroidism (HPD) by a regime of phosphate binders and dietary phosphate restriction. Glucose metabolic rate (M) increased by 34%, insulin response (I) increased by 32%, and insulin sensitivity (M/I) did not change. Compared to corresponding normal values, these patients were glucose-intolerant (low M) before treatment and became glucose-tolerant after treatment (normal M). They were insulin-resistant (low M/I) before treatment and remained so after treatment. The 5 uremic children without secondary HPD were treated with the same regime to prevent the secondary HPD. Their M, I, and M/I did not change after treatment. The change in I correlated closely with the change in M in all 13 patients. One pubertal patient with uremia was studied on three occasions. Initially, without secondary HPD, he had a normal M and a low M/I. When he developed secondary HPD, M decreased by 39%, I decreased by 37%, and M/I did not change. Treatment of his secondary HPD restored M and I values back to initial levels, and M/I again did not change. Treatment of secondary HPD by correction of phosphate retention led to an improvement of glucose intolerance with an increase in insulin secretion.

Adolescent↗
PubMed1983

The relationship between branched-chain amino acids and alpha-keto acids in blood in uremia.

Branched-chain alpha-keto acid (BCKA) supplements are used as a nitrogen-free source of branched-chain amino acids (BCAA) in patients with chronic renal failure. Their use is dependent on the freely reversible interconversion of BCKA and BCAA in muscle tissue. In a group of eight young adults on dialysis compared to 11 normal healthy adults, the ratios of the fasting plasma concentrations of leucine and isoleucine to their corresponding alpha-keto acids, alpha-keto isocaproic acid and alpha-keto-beta-methyl-eta-valeric acid, respectively, were significantly elevated. These ratios appear to be sensitive to changes in intracellular glutamate and pyruvate. The ratios increased in seven insulin-dependent diabetics following insulin withdrawal, a situation where intracellular glutamate is increased. The ratios decreased in six normal healthy adults in response to submaximal treadmill exercise, a situation where intracellular pyruvate is increased. The elevated BCAA/BCKA ratios in uremia could be a reflection of reduced peripheral glucose utilization. A consequence of this will be enhanced conversion of supplemented BCKA to their corresponding BCAA. The close association between muscle BCAA and glucose metabolism suggests that the timing of BCKA administration in relation to energy intake might prove important.

Adolescent↗
PubMed1983

Normal values for plasma creatinine concentration related to maturity in normal term and preterm infants.

Creatinine concentration was measured by a kinetic method in 475 plasma samples obtained from 260 term and preterm infants during the first 2 months post-natal age. In term infants plasma creatinine fell from 88 +/- 4.4 mumol/L (mean + SEM) at birth, to 60 +/- 1.9 mumol/L by the fourth day remaining stable thereafter; in preterm infants creatinine fell to 86 +/- 7 mumol/L by the fourth day. Analysis of pooled data from all infants of more than 4 days post natal age revealed a progressive fall in creatinine with increasing post conceptual age. The normal range of values varies with post conceptual age and was not influenced by gestational age at the time of birth.

Age Factors↗
PubMed1983

Rapidly progressive glomerulonephritis with extensive glomerular crescent formation.

Thirty-nine patients with severe crescentic glomerulonephritis and rapidly progressive renal failure were reviewed. Nineteen patients had a focal necrotizing glomerulonephritis, they usually presented with signs of multi-system disease, and eight had histologically-proven microscopic polyarteritis. A second group of 20 patients presented with an acute nephritic syndrome, often with nephrotic features, and had only minor prodromal symptoms. Renal biopsy material showed various forms of proliferative glomerulonephritis in addition to crescents. The most important prognostic feature at admission was renal function: only four of 21 patients who required dialysis recovered any renal function. The prognosis was worse for those with necrotizing glomerulonephritis, of whom two-thirds had oliguria on admission. All patients who were not oliguric, and some with oliguria, were treated with high doses of corticosteroids, usually accompanied by azathioprine and anticoagulants. Seventeen of 18 patients who were not oliguric initially retained or regained renal function, although three subsequently went into renal failure, and three others died of non-renal causes. At the most recent review, 25 of the 39 patients were either dead (16 patients) on dialysis or transplanted (nine patients). Ten were alive with diminished renal function, one had normal renal function but persisting proteinuria, and three were well. Prompt treatment may have contributed to these favourable results in a very severe disease.

Adolescent↗
PubMed1983

Survival time in cystinosis. A collaborative study.

In a retrospective study the overall survival time of 205 cystinotic patients of six countries was determined. The median survival time was 8.5 years. The median time for 'renal death' (age at death due to uraemia or age at starting renal replacement therapy) was 9.2 years. The youngest patient dying of renal death was 5.2 years. No sex difference in survival time was noticed. Furthermore no difference in survival time was noted between the different countries. The analysis of the overall survival curve indicates no clear differences between the infantile and adolescent types of cystinosis.

Adolescent↗
PubMed1982

Comparison of high-dose intravenous methylprednisolone with low-dose oral prednisolone in acute renal allograft rejection in children.

Two corticosteroid regimens were compared in a randomised, prospective study of 48 consecutive acute rejection episodes occurring at least one month after transplantation in 22 children who had received renal allografts. The higher dose schedule (intravenous methylprednisolone 600 mg/m2 daily for three days) was no more effective than the lower (oral prednisolone 3 mg/kg daily for three days) in reversing rejection, being successful in 70% as opposed to 72% of episodes. Few major side effects were seen with either treatment, but unpleasant sensations were reported much more frequently in the group given intravenous methylprednisolone; this regimen was much more disruptive of the patient's life. Oral prednisolone in the dosage described is as effective as about 10 times that dose of intravenous methylprednisolone; it is much cheaper and is viewed as less unpleasant by patients.

Administration, Oral↗
PubMed1982

Neuropathic vesicourethral dysfunction in children. A trial comparing clean intermittent catheterisation with manual expression combined with drug treatment.

Forty-three children with overt neurological disease and neuropathic vesicourethral dysfunction were entered into a trial comparing clean intermittent catheterisation (CIC) with manual expression combined with drug treatment (non-CIC). The 22 children in the CIC group showed a significantly greater improvement in continence than the 21 children in the non-CIC group (P less than 0.001) without a significant increase in the incidence of urinary tract infections. Neither form of treatment is effective in reducing the risk of deterioration of renal function due to the combination of detrusor-sphincter dyssynergia and vesicoureteric reflux. Neither form of treatment improves continence in the presence of gross sphincter weakness or gross impairment of bladder compliance.

Bethanechol Compounds↗
PubMed1982

Neurological complications of arterial hypertension.

During a 10-year period 45 children were identified as having had neurological complications associated with severe arterial hypertension. Convulsions were the most common complication, occurring in 42 (82%) children. Two (4%) children each presented with a facial palsy and 2 (4%) with alterations in the level of consciousness. Nineteen (42%) presented with epileptic seizures as the first sign of arterial hypertension. The prognosis for children having had a single episode of hypertensive encephalopathy was good. Long-term follow-up showed no permanent neurological deficit on physical examination, and no focal abnormality on brain scan by computerised tomography. Psychometric analysis similarly failed to show any significant difference in cognitive assessment between children having had an episode of hypertensive encephalopathy and a control group with chronic renal disease, although reading skills were generally behind for chronological age and the average IQ was about 90 in both groups.

Adolescent↗
PubMed1982

Effect of indomethacin on clinical progress and renal function in cystinosis.

Three children with nephropathic cystinosis were treated with indomethacin 3 mg/kg a day for periods ranging from 9 to 18 months. The drug produced worthwhile clinical improvement in all, with marked beneficial effects on polyuria, polydipsia, and general wellbeing. Clearance studies performed under conditions of maximal water diuresis showed that proximal tubular sodium reabsorption was increased in all children, with consequent reduction in sodium delivery to the distal nephron leading to reduced free water clearance and distal tubular cation exchange. Plasma sodium and potassium concentrations became normal in all patients, with improvement in phosphate and bicarbonate concentrations in one. Renal function continued to deteriorate, but without obvious acceleration of the process by the drug. We were unable to demonstrate a beneficial effect on growth; nevertheless, indomethacin is a useful adjunct to the symptomatic treatment of children with severe nephropathic cystinosis.

Body Water↗
PubMed1982

Evaluation of a height/plasma creatinine formula in the measurement of glomerular filtration rate.

The clinical usefulness of the quantity height (cm)/plasma creatinine (Ht/Pcr) as a predictor of glomerular filtration rate (GFR) was investigated in 163 children with varying levels of renal function. Plasma creatinine levels (mumol/l) were measured by an automated reaction rate method. The results indicate that in rather more than half the children studied, an estimate of GFR adequate for ordinary clinical purposes will be obtained from Ht/Pcr, or from the derived formula GFR (ml/min per 1.73 m2) = 40 Ht/Pcr. The accuracy of the prediction is greatest in children with reduced function (GFR less than 80 ml/min per 1.73 m2) and in this group of patients a change of GFR of 19 ml/min per 1.73 m2 or more is reliably detected by this method. We conclude that Ht/Pcr is a clinically useful aid to the estimation of renal function, reducing the need for formal GFR measurements by at least half.

Adolescent↗
PubMed1982

Significance of mesangial IgM deposition in "minimal change" nephrotic syndrome.

During a 6-year period, 64 patients with a nephrotic syndrome, shown histologically to result from minimal change nephropathy, were studied for a mean of 4.5 years. Fifty of the patients showed no glomerular immunoglobulin on immunofluorescent or immunoperoxidase study, but 14 had mesangial deposits of IgM. The onset characteristics, response to treatment, and long-term course were similar in the two groups. We conclude that IgM deposition in the mesangium in patients with minimal change nephrotic syndrome is of no prognostic value, and our data do not suggest that this group of patients, although a histopathologic entity, represent a clinically distinct group.

Adolescent↗
PubMed1982

Dialysis treatment and psoriasis in Europe.

One hundred and fifty out of 944 European dialysis centers reported experience with patients suffering from psoriasis. Ninety-three centers returned special questionnaires on 97 patients with end stage renal failure (ESRF patients) and on 49 patients dialyzed for psoriasis but who had normal renal function (NRF patients). Improvement of skin disease was reported in 17 out of 27 NRF patients according to both "objective criteria" and the patients' personal opinions. However, most of these patients had been on dialysis for less than one year (9.9 +/- 11.1 months) which is too short to allow for the spontaneous recurrence of psoriasis. In contrast, 60% of ESRF patients had been on dialysis for 45 +/- 3.1 months. Skin disease definitely improved in 20% of these patients after commencement of dialysis. This proportion is greater than the expected spontaneous long-term remission of psoriasis.

Adult↗