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Biomedical subjects

J A Napier

Publications and source records attributed to J A Napier.

At least 73 records · Page 4Linked to original sources
PubMed1988

Massive feto-maternal haemorrhage: effect of passively administered anti-D in the prevention of Rh sensitization and haemolytic disease of the newborn.

Fourteen mothers carrying ABO compatible but Rh D incompatible pregnancies experienced large feto-maternal haemorrhages (estimated 188 ml, range 50-400 ml red cells). These were all treated with infusions of fresh frozen plasma containing anti-D at a mean immunoglobulin to fetal cell ratio of 129 i.u. (25.8 micrograms)/ml of fetal cells. At 48 h after the infusion 95% of fetal cells had been removed but 3 to 4 days were required for complete removal. The passively administered anti-D was detectable for up to 6-9 months but not after that time. Four of the 14 women had successful pregnancies subsequently although in two of these anti-C + D was present. Of these, one resulted in a clinically affected baby who survived exchange transfusion.

Erythroblastosis, Fetal↗
PubMed1987

Transfusion significance of LWa allo-antibodies.

An example of anti-LWa, arising as a complication during a RhD immunization programme, has been studied for evidence of its likely in vivo haemolytic properties. In vitro testing of the anti-LWa showed it to be largely IgG1 acting by the antiglobulin technique. Results of antibody-dependent cellular cytotoxicity and macrophage phagocytic assays were both negative. However, 99mTc-labelled Lw(a+) donor cells showed a slight reduction in t1/2 (18 h) compared with the normal survival of autologous cells. Despite this observation, and bearing in mind the difficulties of interpreting apparently accelerated destruction of small serologically incompatible red cells, it was concluded that the presence of this example of anti-LWa should not be a bar to urgent transfusion.

Aged↗
PubMed1987

Oral administration of erythrocyte membrane antigen does not suppress anti-Rh(D) antibody responses in humans.

The effects of prior oral administration of erythrocyte membrane preparations (Oral Rh antigen) on the serum anti-Rh(D) antibody response has been evaluated in non-sensitized Rh(D)-negative male volunteers, and in female volunteers sensitized previously by Rh(D)-positive fetal blood during pregnancy. Sixty-one percent (11/18) of males who received oral Rh antigen (either D-positive or D-negative) before intravenous challenge with Rh(D)-positive cells produced detectable antibodies; of these 11, six received oral Rh(D)-negative antigen and five received oral Rh(D)-positive antigen. Seventy-two percent (13/18) of control males, who had received no prior oral Rh antigen, produced antibodies following challenge with Rh(D)-positive cells. Three out of six pre-sensitized females who received oral D-positive or D-negative Rh antigen for 4 weeks, but without intravenous challenge, increased their anti-Rh(D) antibody levels which peaked after 11-18 weeks: two had received Rh(D)-positive antigen, and one Rh(D)-negative antigen. These data indicate that administration of oral Rh antigen before parenteral immunization does not significantly suppress the anti-Rh(D) antibody response. Indeed, oral administration of either Rh(D)-positive or Rh(D)-negative antigen can boost systemic antibody in pre-sensitized females. These results do not support the rationale of treating Rh-sensitized pregnant women with oral Rh antigen.

Administration, Oral↗
PubMed1986

Erythropoiesis in pregnancy.

The reticulocyte count, serum ferritin and serum erythropoietin concentrations were measured during the course of pregnancy in 41 women. A decrease in iron stores early in pregnancy was accompanied by a significant rise in the reticulocyte count until the 28th week. Erythropoietin levels did not rise significantly until the 28th week of pregnancy and had fallen to the post-natal level by 40 weeks. The results are consistent with an increase in erythropoietic activity early in pregnancy which did not appear to depend upon increased plasma erythropoietin levels.

Adult↗
PubMed1985

What is the 'optimum' optimal additive solution?

Spontaneous formation of clotted material occurs occasionally in all stored red cell units, but larger amounts have been noted in SAG-M optimal additive suspensions. These can be substantially reduced by substitution of the SAG-M solution by a SAG-M/CPDA-1 mixture suggesting that there is insufficient citrate in SAG-M red cell suspensions to completely inhibit coagulation of the residual plasma.

Blood Coagulation↗
PubMed1984

Micro-aggregate content of red cell suspensions stored in saline adenine glucose mannitol optimal additive solution.

The micro-aggregate content of blood collected into conventional CPDA-1 preservative was compared with that of red cells stored in saline adenine glucose and mannitol optimal additive preservative solution (SAG-M). The results show that the optimal additive packs from which either platelet rich or platelet poor plasma have been removed contain 38% of the micro-aggregates in CPDA-1 blood. When platelets, plasma and the buffy coat are also removed, the residual micro-aggregates amount to only 16% of those in CPDA-1 whole blood. No differences were seen between the amount of haemolysis in any of the red cell preparations. From these results and previously published guidelines for the use of micro-aggregate filters with whole blood (International Forum 1977) it may be concluded that there is no place for the routine use of micro-aggregate filters with optimal additive preserved blood unless over 12 units are likely to be transfused.

Adenine↗
PubMed1984

The hematological response to continuous ambulatory peritoneal dialysis.

Over the first three months of continuous ambulatory peritoneal dialysis (CAPD) the level of hemoglobin (Hb) rises significantly in most patients. To elucidate this further we studied the hematological response over 3 months of 8, previously non-transfused new patients treated with CAPD. Mean Hb rose by +2.78 g/dl (P less than 0.02). Mean RCM rose by 284 ml (37.7%) (P less than 0.05) and 3.7 ml/kg (29.6%) (P less than 0.05). PV fell relative to BW only, by -8.6 ml/kg (P less than 0.05). There was no significant change in serum vitamin B12 or folate concentrations or evidence of hemolysis. Plasma ferritin fell in all patients, but hematological changes of iron deficiency appeared in only one. Bio-assayable erythropoietin (EPO) levels were generally in the normal range, but inappropriately low for the degree of anemia. EPO did not change significantly apart from in two patients, one with polycystic disease. These results indicate that over the initial 3 months of therapy the majority of CAPD patients have a rise in Hb, due mainly to a rise in RCM, unrelated to changes in serum EPO level.

Adult↗
PubMed1983

The importance of cross-match/transfusion ratio and intervals between successive cross-matches in determining red cell outdate rates.

Measurements have been made of cross-match/transfusion ratios (C/T ratio) and intervals between successive cross-matches on the same units of blood performed in three different major hospitals each providing a wide range of clinical services. Outdate rates were 4%, 15% and 25% respectively and were associated with C/T ratios of 1.3, 2.0 and 2.15. There were corresponding increases (means of 3.6, 4.5 and 5.0 days) in the length of time unused units of blood were left between successive cross-matches. Calculations of outdate rates from the above figures closely predicted the trend shown by observed non-use rates. It has thus been demonstrated that apparently small differences in blood bank practice can produce important variations in the efficiency of use of red cell units.

Blood Banks↗
PubMed1982

Erythropoietin levels in posterior fossa haemangioblastoma.

Using an in vitro bioassay, erythropoiesis stimulating activity has been measured in serum, cyst fluids and tumour homogenates from fourteen patients with cerebellar haemangioblastoma. Only two patients had elevated peripheral blood red cell counts and haemoglobin concentrations. Significantly elevated serum erythropoiesis stimulating activity was found in only one patient. High level, however, were detected in seven out of the fourteen cyst fluids and in the two homogenates tested. The dose response lines from these paralleled those of normal human erythropoietin. It was possible to neutralise the erythropoiesis stimulating activity in the cyst fluids with anti-human erythropoietin serum, indicating its similarity to erythropoietin, the normal erythropoietic regulating hormone. Significant release of the erythropoietic stimulating factor from the cyst fluids into the blood seemed to be an uncommon occurrence.

Adult↗
PubMed1981

Erythropoietin measurements in the differential diagnosis of polycythaemia.

An in vitro bioassay has been used to measure erythropoietin levels in extracts of serum from 74 patients with polycythaemia. Patients with polycythaemia vera in relapse had subnormal or undetectable levels which did not increase after challenge by venesection. In polycythaemia secondary to hypoxaemia serum erythropoietin concentrations were generally elevated with a further elevation occurring after venesection. Where polycythaemia was secondary to renal polycystic disease or tumours increased levels of erythropoietin could not be consistently demonstrated. In these patients the serum erythropoietin was unaffected by venesection. In other patients in whom the cause for polycythaemia was unknown examples of each of the above patterns were seen. Erythropoietin investigations in such patients may help in the elucidation of the underlying pathology.

Adult↗
PubMed1981

Red cell antibodies detected in antenatal tests on rhesus positive women in South and Mid Wales, 1948-1978.

A total of 733 rhesus positive women with antibodies were found during antenatal screening of 380,790 pregnancies in South and Mid Wales, over a 30-year-period. A steady increase was observed in the frequency of antibodies, particularly non-rhesus antibodies and the mothers concerned had a significantly increased history of previous blood transfusion. In 50 per cent of those with non-rhesus antibodies, transfusion was the only stimulus. Conversely, for the majority (61 per cent) of women with rhesus antibodies feto-maternal incompatibility was the sole apparent stimulus. No identifiable stimulus could be found in 25 per cent of women with anti-E and 13 per cent of those with anti-Kell. Compared to rhesus negative mothers with anti-D severe clinical haemolytic disease of the newborn was uncommon, but in 75 per cent of rhesus positive mothers with infants carrying the homologous antigen, there was some evidence of haemolytic disease. Anti-c was much the worst in this respect with 19.4 per cent of infants needing transfusion. The probability of having an incompatible infant was much less for the mothers with non-rhesus antibodies (27.3 per cent) and of these infants only 5.7 per cent needed transfusion.

Blood Group Antigens↗
PubMed1980

Erythropoietin assay using fetal mouse liver cell cultures: a modified technique using semi-automatic harvesting of I125 deoxyuridine labelled erythroblasts.

Modifications have been made to the fetal mouse liver cell bioassay for erythropoietin in an attempt to make the method easier and to improve specificity. Pooled human serum is used as a diluent for test serum samples, standard and control preparations in order to minimize the influence of other serum constituents on the assay results. Erythroblast proliferation is measured by incorporation of I125 deoxyuridine into DNA. The cell cultures are grown in microtitration plates and harvested semi-automatically on to glass fibre filter mats for determination of radioactivity.

Animals↗