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Biomedical subjects

C Chapman

Publications and source records attributed to C Chapman.

At least 109 records · Page 6Linked to original sources
PubMed1991

Changes in serum erythropoietin levels during allogeneic bone marrow transplantation.

Serial serum erythropoietin levels were measured in 10 consecutive patients undergoing allogeneic bone marrow transplantation. Observed erythropoietin levels are compared with those predicted from a large control population of anaemic patients not receiving chemotherapy. There was an initial acute rise in serum erythropoietin, peaking between days 1 and 4 after marrow transfusion, which was unrelated to changes in haemoglobin concentration. Patients maintained serum erythropoietin concentrations at around twice the predicted level for the first 2 weeks following transplantation, with a gradual fall into the expected range by wk 3. Erythropoietin levels did not change with episodes of bacterial infection or acute graft-versus-host disease. A patient with severe aplastic anaemia had initial successful engraftment with normalisation of erythropoietin levels, but showed a marked and amplified rise in erythropoietin 2 wk before falling peripheral blood counts indicated failure of the bone marrow graft.

Adolescent↗
PubMed1991

Progressive renal toxicity due to ifosfamide.

A prospective and follow up study of renal tubular and glomerular function in 11 children receiving ifosfamide treatment was conducted. Each child received between four and 14 courses of ifosfamide, given as a continuous infusion of 3 g/m2 over 24 hours for two or three days. Evidence of renal toxicity was seen in all patients. There was a treatment related rise in urinary tubular markers (N-acetyl-glucosaminidase and alpha 1 microglobulin). Recovery was limited, so that by the fourth course of treatment all values remained abnormal. There was an associated treatment related reduction in plasma phosphate concentration. Urinary albumin also showed a treatment related rise, but with fewer abnormal values. Electrophoresis was used to confirm tubular or glomerular patterns. Glomerular toxicity was less severe and occurred in fewer patients. The follow up study showed persistence of tubular damage in all seven patients examined, and there was evidence of glomerular damage in five of the seven children. Children receiving ifosfamide need to be carefully monitored for renal toxicity both during treatment and at follow up.

Acetylglucosaminidase↗
PubMed1991

Field methods for capture and measurement of three monkey species in Costa Rica.

A total of 54 free-ranging monkeys were captured and marked in Santa Rosa National Park, Costa Rica, during May 1985, and an additional 17 were captured during March 1986. The animals were darted using a blowpipe or a CO2 gun. The drugs used were Ketaset, Sernylan and Telazol. Ketaset was effective for Cebus capucinus but unsuccessful for Alouatta palliata and Ateles geoffroyi. Sernylan was successful for A. geoffroyi and A. palliata but is no longer commercially available. Telazol proved to be an excellent alternative capture drug for both A. palliata and A. geoffroyi.

Alouatta↗
PubMed1991

Transferrinuria in type 2 diabetes: the effect of glycaemic control.

Urinary excretion rates of transferrin, albumin, N-acetyl-beta-D-glucosaminidase (NAG) and alpha-1-microglobulin (A1M) were measured in type 2 (non-insulin-dependent) diabetic patients at diagnosis and after 6 and 12 weeks treatment. Initially 21 (53%) patients had elevated transferrin excretion rates. The proportion of patients with raised transferrin excretion rates fell to 30% at 6 weeks and 20% at 12 weeks with treatment of diabetes. At diagnosis 11 (28%) patients had elevated albumin excretion rates and 10 of these had elevated transferrin excretion rates. After 6 weeks treatment only six (15%) had elevated albumin excretion rates and by 12 weeks this number had fallen to four (10%). NAG and A1M levels also fell with treatment of diabetes. There were correlations between the transferrin excretion rate and albumin excretion rate (r = 0.86, P less than 0.0001), transferrin excretion rate and NAG (r = 0.46, P less than 0.0001), and transferrin excretion rate and A1M (r = 0.55, P less than 0.0001) at each visit. There were weaker correlations between the albumin excretion rate and A1M and NAG at each visit. The correlations between the transferrin excretion rate and markers of tubular function (NAG and A1M) suggest that tubular dysfunction may play a part in renal loss of transferrin in diabetes mellitus. There were no differences in transferrin excretion rates between patients with and without evidence of complications.

Adult↗
PubMed1991

Increased urinary transferrin excretion in exercising normoalbuminuric insulin-dependent diabetic patients.

The median rate of urinary transferrin excretion is greatly increased by exercise in subjects with uncomplicated type 1 (insulin-dependent) diabetes. This increase is proportionally far greater than that seen in urinary albumin excretion rate after the same exercise. Non-diabetic control subjects showed no rise in urinary transferrin excretion rate following exercise. N-acetyl-beta-D-glucosaminidase excretion rate was higher in diabetic than control groups but did not rise with exercise. Our results suggest that patients with apparently uncomplicated diabetes have abnormal renal function. In this group an elevated urinary transferrin excretion rate appears to be a more sensitive indicator of altered renal function than is elevated albumin excretion rate. The mechanism underlying exercise-induced urinary loss of transferrin remains to be elucidated.

Acetylglucosaminidase↗
PubMed1991

The use of vidarabine in the treatment of human polyomavirus associated acute haemorrhagic cystitis.

The human BK and JC polyomaviruses are known to be reactivated and excreted in the urine following bone marrow transplantation (BMT). A proportion of patients who excrete BK virus following BMT experience a haemorrhagic cystitis (HC), which may persist for many months. We report a case of human polyomavirus-associated HC, in whom treatment with vidarabine was associated with a dramatic response.

Acute Disease↗
PubMed1990

Long-term prognostic value of serum beta 2 microglobulin in myelomatosis.

The prognostic value of serum beta 2 microglobulin (s beta 2m) measured at entry, at plateau and at 3-monthly follow-up times has been assessed for patients in the Medical Research Council's 4th and 5th Myelomatosis Trials. Analysis of 1014 patients confirmed the value of presentation s beta 2m of predicting survival in the short term but showed that predictive value was lost for subsequent survival in those patients who had survived for at least 2 years. However, measurements of s beta 2m taken during follow-up were predictive of subsequent survival. The predictive power of these follow-up measurements was very similar to that for the presenting measurement, and again they were only of value in predicting survival in the next 2 years.

Calcium↗
PubMed1990

Increased urinary excretion of transferrin in children with type 1 diabetes mellitus.

Urinary transferrin excretion was measured by radioimmunoassay in 74 children with Type 1 diabetes mellitus and in 40 normal children, and compared with urinary excretion of albumin, alpha-1-microglobulin, and N-acetyl-beta-D-glucosaminidase. Urinary transferrin excretion was significantly elevated in diabetic (median (range) 186 (18-1671) mg mol-creatinine-1) compared with normal (85 (27-668) mg mol-creatinine-1) children (p less than 0.001). Seventeen diabetic children had transferrin excretion above the 95th centile for normal children. In contrast there was no significant increase in urinary albumin excretion in the diabetic children although 8 had urinary albumin excretion which exceeded the 95th centile for normal children (6 of these 8 patients having coexistent urinary hyperexcretion of transferrin). Urinary transferrin excretion correlated significantly with urinary albumin excretion in both normal (rs = 0.62, p less than 0.001) and diabetic (rs = 0.61, p less than 0.001) children. The indices of proximal renal tubular function (urinary excretion of alpha-1-microglobulin and N-acetyl-beta-D-glucosaminidase) correlated significantly with transferrin excretion in both diabetic (rs = 0.43 and rs = 0.41, p less than 0.001) and normal (rs = 0.40, p less than 0.02 and rs = 0.53, p less than 0.001) children, but not with albumin excretion (rs = 0.20, p greater than 0.05 and rs = 0.22, p greater than 0.05). In addition urinary transferrin excretion significantly correlated with urinary glucose concentration (rs = 0.34, p less than 0.007) in Type 1 diabetic children. The discrepancy in urinary excretion of transferrin and albumin may reflect impaired proximal renal tubular reabsorption of transferrin and/or altered glomerular basement membrane selectivity for the two proteins.

Acetylglucosaminidase↗
PubMed1990

A novel T-cell protein which recognizes a palindromic sequence in the negative regulatory element of the human immunodeficiency virus long terminal repeat.

Two major protein-binding sites within the negative regulatory element of the human immunodeficiency virus type 1 long terminal repeat have been identified. One (site B) contained a palindromic sequence with homology to steroid/thyroid hormone response elements but was distinct from previously described binding sites of this class. A novel T-cell protein recognized the palindromic sequence within site B and also bound estrogen- or thyroid hormone-response elements with lower affinity. A 7-base-pair mutation in the site B palindrome, which destroyed protein binding, resulted in increased expression from the human immunodeficiency virus type 1 long terminal repeat in T cells.

Base Sequence↗
PubMed1990

Microbumintest and non-albumin proteinuria in diabetes.

Bedside methods for the detection of microalbuminuria such as Microbumintest (TM) have the advantage of simplicity but not the specificity of radio-immunoassay. In the present study we assessed whether apparently inappropriate positive Microbumintest results in the presence of low urinary albumin concentrations could be accounted for by non-albumin proteinuria of glomerular or renal tubular origin. Urinary albumin and transferrin were considered to indicate glomerular proteinuria, and alpha-1-microglobulin and N-acetyl-beta-D-glucosaminidase to reflect tubular proteinuria. Microbumintest had a sensitivity of 100% and specificity of 67% to detect a urinary albumin concentration of 40 mg/l. Samples with albumin concentration less than 40 mg/l contained more total protein: 110 (78-155) v 60 (35-104) mg/l p less than 0.0001 (geometric means with 1 SD range), more albumin: 11.7 (5.1-26.8) v 5.4 (2.8-10.4) mg/l p less than 0.005 and more transferrin: 496 (191-1284) v 174 (78-389) micrograms/l p less than 0.001, in those testing positive with Microbumintest than in those testing negative. Microbumintest had a sensitivity of 82% and specificity of 75% to detect an albumin concentration of 20 mg/l. In samples containing less than or equal to 20 mg/l albumin, the mean albumin concentration was no greater in those testing positive compared with those testing negative. However, total protein: 108 (72-161) v 60 (34-105) mg/l p less than 0.001, and transferrin: 326 (148-715) v 157 (78-316) micrograms/l p = 0.01 both remained increased in samples testing positive compared with those testing negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1988

Opioid inhibition of secretion from oxytocin and vasopressin nerve terminals following selective depletion of neurohypophysial catecholamines.

Opioids intrinsic to the neurohypophysis inhibit secretion from magnocellular neurosecretory terminals. This study examined whether the actions of opioids are mediated via interactions with neurohypophysial catecholamine systems. Blocking the action of intrinsic opioids in the isolated neurohypophysis with naloxone enhanced evoked secretion of oxytocin (OXT) by 150% and of vasopressin (AVP) by 30%. The enhancement of OXT secretion was not significantly altered in neurohypophyses depleted of greater than 90% of noradrenaline content by prior lesion of the ventral noradrenergic tract, or depleted of greater than 90% of both noradrenaline and dopamine content by prior reserpine treatment. Significant enhancement of AVP secretion by naloxone did not occur following depletion of catecholamines. The data suggest: (1) the majority of the influence of intrinsic opioids on secretion of OXT is not mediated via interaction with noradrenaline or dopamine systems, (2) the weaker influence of intrinsic opioids over AVP secretion may be mediated via catecholamines, (3) the majority of neurohypophysial noradrenaline is derived from projections of ascending medullary cell groups.

Animals↗
PubMed1988

Functional kappa-opioid receptors on oxytocin and vasopressin nerve terminals isolated from the rat neurohypophysis.

Opioids intrinsic to the rat neurohypophysial system act to inhibit secretion from the terminals of magnocellular neurones. Opioid receptors in the neurohypophysis are predominantly of the kappa-subtype and selective kappa-agonists suppress electrically evoked release of oxytocin (OXT) and vasopressin (AVP). We have looked for the presence of functional kappa-receptors on neurohypophysial nerve terminals by examining effects of kappa-agonists on secretion from suspensions of isolated neurohypophysial nerve terminals (neurosecretosomes) retained on filters in a perifusion system. Release of both OXT and AVP evoked by K+-depolarisation was inhibited by the kappa-agonists U-50,488H (34% and 45% respectively) and dynorphin A1-13 (68% and 51% respectively). Inhibition by dynorphin A was only observed in the presence of peptidase inhibitors. The actions of both kappa-agonists were prevented by the opioid receptor antagonist naloxone. The experiments indicate the presence of kappa-receptors on terminals of OXT and AVP neurones. This receptor population is in addition to those previously described on pituicytes and those influencing release of neurohypophysial noradrenaline.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗