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Biomedical subjects

C H Walker

Publications and source records attributed to C H Walker.

At least 127 records · Page 7Linked to original sources

The effects of 1,1-di(p-chlorophenyl)-2-chloroethylene on plasma enzymes and blood constituents in the Japanese quail.

Glutamate oxaloacetate transminase (GOT), glutamate dehydrogenase (GDH), sorbitol dehydrogenase (SDH), pseudo-cholinesterase (ChE) and various blood constituents were measured in the plasma of Japanese quail fed 1,1-di(p-chlorophenyl)-2-chloroethylene (DDMU) at low levels for periods ranging from 2 to 32 days. Previous work has shown that DDMU is a potent inducer of hepatic microsomal enzymes causing marked structural changes in the liver. A rapid increase in plasma GOT was observed within 4 days accompanied by an increase in relative liver weight. Plasma GDH and SDH increased to a maximum between 16 and 24 dyas which seems to be associated with hepatic cell proliferation. Plasma ChE showed a steady increase over the time course of DDMU administration. The level of plasma lipid was reduced after 4 days whereas the hepatic lipid content was substantially increased suggesting that the fatty liver condition may be caused by decreased release of triglyceride from the liver. Plasma glucose was reduced at 8 days but there was no evidence of a hyperglycaemic state. The changes noted after 2 days of DDMU diet were confirmed by measurements on birds 18 h after oral dosing the DDMU. The study demonstrates the value of plasma enzyme measurements for the early detection of toxic effects and indicates that DDMU administration leads to extrahepatic effects in addition to those previously described in the liver.

Animals↗

Effects of pethidine and its antagonists on the newborn.

Nalorphine and naloxone were compared as to their effectiveness as pethidine antagonists. 85 infants were divided into a control group containing 19 newborn babies whose mothers did not receive pethidine and the babies received no antagonist, and three groups in which the mothers all received pethidine and the babies had either no antagonist (24), nalorphine IV (16), or naloxone IV (26). All the babies were assessed by measuring their neurobehavioural states and respiratory functions. A further 12 newborn babies had naloxone plasma levels measured by radioimmunoassay. Although standard doses of nalorphine effectively antagonised the depressive effect on respiration induced by pethidine, there was a pronounced and undesirable excitatory agonist action. Naloxone was not observed to have any agonist activity, but the recommended IV dose (0.01 mg/kg) had only a slight and delayed antagonist action as measured by respiratory function tests. A more rapid and improved antagonism was noted after this dose was doubled (0.02 mg/kg). The plasma elimination-phase half-life of naloxone after intravenous cord injection was about 3 hours.20

Carbon Dioxide↗

Changing pattern of respiratory distress in newborn.

A retrospective study of respiratory distress in a special-care baby unit revealed that transient tachypnoea of the newborn (T.T.N.B.) lasting more than 24 h was as common as the respiratory distress syndrome (R.D.S.). Delivery by caesarean section was associated with T.T.N.B. and the results of measurement of crying vital capacity in caesarean section and vaginally delivered babies indicate that babies delivered by caesarean section are at a considerable disadvantage during the first few days of life.

Anthropometry↗

Neonatal records and the computer.

To use a combined single document clinical case sheet/computer record which can form the basic document for a life medical record is a practical proposition. With adequate briefing doctors and nurses soon become familiar with the record and appreciate its value. Secretarial and clerical requirements are reduced to a minimum as transcription of medical data is eliminated, so greatly speeding up processing and feed back to the medical services. A few illustrations of trends in neonatal statistics and of computer linked maternal/neonatal data are presented.

Computers↗

The metabolism of organochlorine compound by microsomal enzymes of the shag (Phalacrocorax aristotelis).

1. The activities of microsomal enzymes of adult male shags (Phalacrocorax aristotelis) towards the organochlorine substrates HHDN, HCE and Heom were compred with those of microsomal enzymes of the adult male Wistar rat. 2. Liver homogenates showed similar epoxide hydrase activity to kidney homogenates in the shag, but in the rat liver preparations was much more active than the kidney preparation. 3. Liver microsomes of the shag showed smaller than 8% of the epoxide hydrase activity and smaller than 14% of the hydroxylating capacity of liver microsomes from the rat. 4. The relatively low activity of these enzymes is probably the main reason why the shag has been found to contain relatively high levels of dieldrin in ecological studies.

Aldrin↗