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Biomedical subjects

P M Emerson

Publications and source records attributed to P M Emerson.

13 recordsLinked to original sources
PubMed1979

Clinical events relating to intraventricular haemorrhage in the newborn.

Continuous measurements of arterial pressures, heart rates, respiratory movements, and respiratory rates were made from birth in 44 infants at risk from intraventricular haemorrhage (IVH). 17 babies died with IVH, in 10 of whom the event was timed objectively. Events in these babies were compared with survivors of similar birthweights, gestational ages, severity of birth asphyxia, and severity of hyaline membrane disease (HMD). IVH followed severe HMD and was associated with cessation of the babies' own respiratory efforts while on a ventilator and also with characteristic cardiorespiratory events. The minimum arterial pressure before IVH was lower than in comparable babies who survived. It is suggested that fluctuations of systemic blood pressure from initial low levels may be important in the pathogenesis of IVH. It is possible that changes in cerebral blood flow are of even greater significance.

Asphyxia Neonatorum↗
PubMed1979

An improved method for the measurement of red cell survival using non-radioactive chromium.

An improved technique for the measurement of red cell survival is described in which non-radioactive 50Cr is used in patients for whom radioactive labels are not advisable. The 50Cr was measured by neutron activation analysis using a high resolution germanium (lithium) diode gamma-ray spectrometer. In adult controls, the values obtained were in the range accepted as normal for the 51Cr method, and double labelling experiments showed close agreement. The application of this technique to the measurement of red cell survival in pregnant women suspected of having haemolytic anemia is described.

Adolescent↗
PubMed1979

Congenital haemolytic anaemia resulting from glucose phosphate isomerase deficiency: genetics, clinical picture, and prenatal diagnosis.

Glucose phosphate isomerase (GPI) deficiency with severe haemolysis and hydrops fetalis was found in the first child of unrelated, healthy Caucasian parents. The child died at 3 hours. Both parents were found to have 50% of normal red cell GPI activity and qualitative tests on their red cells and white cells showed that each was heterozygous for a different GPI variant allele associated with enzyme deficiency. Tests on the placenta showed that the propositus was a 'compound' heterozygote. Examination of amniotic cells obtained by amniocentesis on the mother at 28 weeks in her second pregnancy led to the prenatal diagnosis of GPI deficiency. This second child, a 'compound' heterozygote at the GPI locus indistinguishable from the first, was successfully treated by immediate exchange transfusion and subsequent blood transfusions.

Adult↗
PubMed1977

Hydroxyethyl starch. An agent for hypovolaemic schock treatment II. Urinary excretion in normal volunteers following three consecutive daily infusions.

1 Urinary hydroxyethyl starch (HES) concentrations were determined by the anthrone method, in four healthy normal male volunteers following three consecutive daily 500 ml infusions (total 1500 ml), in order to ascertain excretion rates under normal controlled conditions. 2 The HES was excreted at a rate of 2.57, 2.46, and 2.44 g/h during the first hour postinjection, on days 1, 2, and 3, respectively. 3 The rate during the interval 12-24 h postinjection, averaged 0.14, 0.21, and 0.10 g/h, on days 1,2, and 3, respectively. 4 In the intervals 24-72, 72-120, and 120-168 h after the third and final injection, the excretion rate was 0.07, 0.04, and 0.02 g/h, respectively. 5 Renal function, as assessed by serum creatinine and uric acid concentrations and 24 h void volumes, was normal during the entire period of observation. 6 The results indicate that HES is excreted at a similar rate following three consecutive daily infusions without evidence of renal injury.

Adult↗
PubMed1977

Development of Neutrophilia by serially increasing doses of dexamethasone.

Dexamethasone (4-8 mg/m2 body surface area) was given orally or intravenously to six normal volunteers. The maximum neutrophil count occurred 4-6 h after oral or intravenous administration of dexamethasone and was due almost entirely to an increase in mature neutrophils; concomitantly there was a lymphocytopenia. A second rise in the neutrophil count occurred 24 h after oral ingestion of dexamethasone, coinciding with a lymphocytosis. Neutrophil alkaline phosphatase (NAP) activity during development fell as the neutrophil count rose. Other haematological values were unchanged except for small increments in erythrocyte sedimentation rate (ESR). Sodium concentration in serum and urine remained normal but urinary potassium excretion and urine volume increased after the intravenous dose. There was a direct relationship between plasma concentration of dexamethasone and the rise in neutrophil count following intravenous but not oral administration. The concentration of dexamethasone in plasma fell to half its peak value in 2-6 h. Dexamethasone-induced neutrophilia was similar to that induced by other corticosteroids. Dexamethasone in a dose of 6 mg/m2 produced minimal discomfort while inducing an adequate neutrophilia in the volunteers.

Adult↗
PubMed1976

Utilization of a new strength citrate anticoagulant during centrifugal plateletpheresis. I. Assessment of donor effects.

A reduction of donor effects during centrifugal plateletpheresis with the Haemonetics Blood Processor was achieved by reducing the concentration of the citrate anticoagulant. Serum citrate and ionized calcium levels, immediately and 1 h post-pheresis, were affected to a lesser extent by using 5.0 g total ionized citrate (TIC) THAN WITH EITHER 8.0 G OR 11.0 G. Total calcium, bicarbonate, prothrombin time, partial thromboplastin time, ECG, and platelet counts were affected to a similar degree by all three TIC formulations. The total number of platelets collected per litre of blood processed was not significantly different among the three TIC formulations. In vitro studies employing the screen filtration pressure (SFP) technique showed no evidence of platelet aggregates in whole blood collected into either 0.01 M or 0.005 M citrate and agitated or left stationary at room temperature for 5 h. The use of different citrate concentrations in plateletpheresis is discussed.

Anticoagulants↗
PubMed1976

Tissue oxygenation and red cell 2,3-diphsophoglycerate in normal and abnormal pregnancy.

Maternal tissue oxygenation was reflected by the level of red cell, 2,3-diphosphoglycerate (DPG) was measured before, during and after normal pregnancy. Following an initial fall at the beginning of pregnancy there was a significant rise in the mean level of DPG during pregnancy with an abrupt fall in the puerperium. The mean red cell DPG level in the third trimester of pregnancies complicated by pre-eclampsia and diabetes was not statistically different from the normal but the mean value of all pregnancies in which the fetus was stillborn or growth retarded was significantly lower (p less than 0-001). The possible mechanism of the changes in normal and abnormal pregnancy is discussed and it is suggested that the measurement of red cell DPG in the third trimester of pregnancy may prove to be a useful parameter of placental oxygenation.

Diphosphoglyceric Acids↗
PubMedDate not supplied

Oxygen availability during hypothermic cardiopulmonary bypass.

Oxygen availability during cardiopulmonary bypass was assessed in 22 patients under hypothermic and relatively normothermic conditions. The patients were divided into two groups, 17 of whom received ACD blood and 5, CPD blood. The mean P50 for all patients fell from a preoperative value of 25.9 +/- 2.4 (SD) to 15.6 +/- 2.1 during hypothermia confirming a leftward shift of the oxyhemoglobin dissociation curve. Oxygen uptake, calculated from a-v oxygen content differences (avDO2) and flow, was significantly lower during hypothermic bypass (65 +/- 27 ml/min) than during rewarming (121 +/- 41 ml/min). The increase in oxygen affinity during hypothermia was influenced also by changes in acid base and 2,3-DPG concentrations, the changes being similar in both the ACD and CPD groups of patients. During rewarming, however, oxygen availability was increased in the CPD group presumably from significantly increased 2,3-DPG concentrations. A "functional" value of hemoglobin, based upon the effects of the shift of the oxyhemoglobin dissociation curve and, therefore, reflecting the true capacity of hemoglobin to unload oxygen at the tissue level, was calculated. During the hypothermic phase of bypass, this functional hemoglobin was only 4.2 g/100 ml blood, suggesting that, in spite of reduced metabolic demands, oxygenation reserves are minimal.

Adult↗