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Biomedical subjects

S Lowson

Publications and source records attributed to S Lowson.

8 recordsLinked to original sources

Effect of metoclopramide on renal vascular resistance index and renal function in patients receiving a low-dose infusion of dopamine.

Metoclopramide is a dopamine receptor antagonist and, in large doses, has been shown to reverse the increase in renal blood flow, the diuresis and the natriuresis produced by a low-dose infusion of dopamine. We gave a single i.v. dose of metoclopramide 10 mg to 21 patients on an intensive care unit who were haemodynamically stable and receiving dopamine 3 micrograms kg-1 min-1. Renal vascular resistance index, measured by duplex Doppler ultrasonography, did not change after metoclopramide. Renal function, measured by creatinine and osmolar clearance, natriuresis, kaliuresis and excretion fractions of sodium and potassium did not change after metoclopramide. We conclude that normal doses of metoclopramide (< 0.2 mg kg-1) do not antagonize the renal effects of a low-dose infusion of dopamine in critically ill patients.

Adult↗

Convulsive thresholds in mice during the recovery phase from anaesthesia induced by propofol, thiopentone, methohexitone and etomidate.

1. Convulsive thresholds were measured with intravenous pentylenetetrazol in mice during the recovery phase after intravenous anaesthetic doses of propofol (10 and 20 mg kg-1), thiopentone (30 mg kg-1), methohexitone (10 mg kg-1), and etomidate 3 mg kg-1). 2. The convulsive threshold rose after each agent, indicating an anticonvulsant action for all the drugs tested; this declined to control values with initial half times of: 1.56 min (propofol 10 mg kg-1); 1.03 min (propofol 20 mg kg-1): 1.02 min (methohexitone); 3.35 min (etomidate); 13.7 min (thiopentone). 3. At no time during the recovery phase of any agent did the convulsive threshold fall below control values, which might indicate an epileptogenic effect of the drug. 4. The threshold was depressed below control values by intravenous administration of Ro 15-4513, a partial inverse agonist at the benzodiazepine receptor, thus indicating the ability of this pentylenetetrazol test to demonstrate a proconvulsant effect. 5. We conclude that the abnormal movements or convulsions associated with recovery from anaesthesia with short-acting intravenous anaesthetics may not be the result of an intrinsic proconvulsant action of the drugs.

Anesthesia, Intravenous↗

Anticonvulsant properties of propofol and thiopentone: comparison using two tests in laboratory mice.

Experiments were carried out in mice to assess the protection provided by thiopentone (Intraval, May and Baker) and propofol (Diprivan, I.C.I.) against epileptiform seizures induced by electroshock and pentylenetetrazol. Intraperitoneal administration of propofol 50 mg kg-1 and thiopentone 25 mg kg-1 produced similar peak behavioural effects of mild sedation and incoordination. However, at these doses propofol afforded a greater degree of protection against pentylenetetrazol than thiopentone and at greater doses both propofol and thiopentone caused marked protection. Both anaesthetics were effective also against electroshock seizures at sedative doses. We conclude that propofol has strong anticonvulsant properties.

Animals↗

Serum ferritin concentration in sickle cell crisis.

Serum ferritin, aspartate aminotransferase (AST), alkaline phosphatase and hydroxybutyrate dehydrogenase (HBD) were studied during 21 vaso-occlusive crises in 12 adults with sickle cell disease (11 SS, 1 S beta degrees). The patients comprised three groups: those who had been untransfused (4), those who had received occasional exchange transfusion in crisis (3), and those who had been multiply transfused (5). Serum ferritin concentrations in crisis were compared with those of the steady state value. Rises in serum ferritin concentrations occurred in all crises in all groups. Although AST, alkaline phosphatase, and HBD rose, there was no correlation between these and log ferritin concentrations. The clinical impression was that the degree of rise in ferritin related to the severity of the particular crisis, and the above results showed that haemolysis and liver damage were not causally related to this rise. An estimate of serum ferritin cannot be used to assess the state of iron balance in sickle cell disease unless the patient is in the steady state. The considerable rise in serum ferritin concentration found in crisis, however, may be a useful marker of the extent of vaso-occlusion and tissue damage.

Adolescent↗

The growth of an NDU in a paediatric outpatient department.

The granting of nursing development unit (NDU) status to a paediatric clinical area indicates the desire to promote excellence in child care. This article describes the progress of the children's outpatient department at Southampton General Hospital since it was granted NDU status.

Clinical Nursing Research↗

Developing a centre for health information and promotion.

Following the successful application for nursing development unit funding, the children's outpatient department within the Child Health Directorate of the University Hospital, Southampton, has developed a number of ambitious plans to promote nursing initiatives, one of which was the creation of a centre for health information and promotion. This article describes this development.

Caregivers↗