The Encapsulation of Squid Diisopropylphosphorofluoridate-Hydrolyzing Enzyme within Mouse Erythrocytes

This study describes the entrapment of squid-type diisopropylphosphorofluoridate-hydrolyzingenzyme (DFPase) within mouse red blood cells. These erythrocytesthereby gain the ability to rapidly hydrolyze alkylphosphatecholinesterase (ChE) inhibitors such as diisopropyl fluorophosphate(DFP). DFPase rapidly hydrolyzes DFP to diisopropyl phosphate.Resealed erythrocytes provide a stable carrier system that canpreserve the activity of encapsulated enzymes against otherwiserapid in vivo degradation; thus, ChE inhibitors can be degradedto relatively nontoxic metabolites by these erythrocyte carriers.Squid DFPase was purified from the hepatopancreas of Atlanticsquid and DFPase activity was determined by measuring changesin fluoride ion concentration using a fluoride ion selectiveelectrode. Mouse erythrocytes in suspension with excess squidDFPase were dialyzed against hypotonic buffer to allow the encapsulationof the enzyme to occur. Cells were then resealed by returningthe suspension to isosmotic with saline. Rate of DFP hydrolysisobserved with these cells was much greater than the rate ofnonenzymatic hydrolysis and was directly proportional to theamount of the erythrocyte suspension added to the assay solution.The rate of hydrolysis was first order in substrate. Erythrocytecontrols showed no endogenous DFPase activity. These resultssuggest that enzyme entrapment may be developed as a methodto prevent and antagonize organophosphate poisoning.     

Age as a Major Factor Affecting Adherence to Medication for Hypertension in a General Practice Population

Weingarten M A and Cannon B S. Age as a major factor affectingadherence to medication for hypertension in a general practicepopulation. Family Practice 1988; 5: 294–296. An audit of the treatment of hypertension in a general practicerevealed that 51 out of 246 patients prescribed medication didnot collect their monthly supply of drugs. There were no significantdifferences between the adherers and the non-adherers in sex,severity of hypertension, type or complexity of medication.The patient's age was the only factor which was associated withadherence. Patients under the age of 55 years or over 65 yearshad significantly lower adherence than those aged 55–64years. Most previous studies coming from hospital-based or clinicaltrial populations have failed to demonstrate this associationwith age which may be characteristic of an unselected generalpractice population. The results may not be applicable to populationsof different social or cultural background but they suggestappropriate directions for health promotion efforts in our community.     

EFFECTS OF INCREASED CARDIAC OUTPUT ON PULMONARY BLOOD FLOW DISTRIBUTION DURING LOBAR VENTILATION HYPOXIA AND COLLAPSE

Electromagnetic flow probes were placed around the pulmonaryartery and left lower lobe artery in anaesthetized open-chestdogs in order to measure possible changes in the ratio of lobar-to-totalpulmonary blood flow (l/t) in response to changes in cardiacoutput produced by the opening of arterio-venous fistulae orfluid loading. Ventilation of the lobe with 7% oxygen or lobarcollapse reduced l/t by 35% and 42%, respectively, butthere were no significant changes in l/t in response to increases in t of 29–133%. It is concludedthat the changes in t, pulmonary vascular pressures and mixed venous PO₂ within the range studieddid not influence l/t.     

Hypothermic effects of apomorphine homologues in mice

A single intraperitoneal (i.p.) injection in mice of apomorphine (I) and its analogues norapomorphine (II), N-ethylnorapomorphine (III), N-n-propylnorapomorphine (IV) and apocodeine (V), caused dose-related decreases in deep-core body temperature. The neuroleptic agent haloperidol blocked the hypothermia produced by these apomorphines but α-methyl-p-tyrosine failed to do so. This indicated a direct post-synaptic stimulation of dopamine receptors. Methysergide potentiated the hypothermic effect of the apomorphine analogues. Taking the amount of apomorphine to produce a 3 °C fall in temperature at 30 min as unity, the approximate relative potencies were: I 1.00, II 0.06, III 47.50, IV 85.00, V 0.340. The doses of the apomorphines needed to produce hypothermia were much less than those needed to cause stereotypy. The ratios of the minimal doses required to produce hypothermia, to those producing stereotypy were: I 8.82, II 4.00, III 125.00, IV 28.50, V 1.43.