PHARMACOLOGICAL CONTROL OF BLOOD-PRESSURE

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1149galactose, continuous synthesis of complex carbohydrates,such as glycoprotein, had been observed in the region of theGolgi apparatus of many cells.KURT HIRSCHHORN (New York) described the potential ofthe lymphocyte for D.N.A., R.N.A., and protein synthesis and forundergoing morphological changes and mitosis. He describedthe lymphocyte as an immunological memory cell capable oflearning from macrophages and thereafter carrying memory forsuch processes as delayed-type hypersensitivity for as long asfive to twenty years. This understanding of the function of thelymphocyte should lead to a better prediction of homograftrejection by means of an in-vivo/lymphocyte-transfer skintest and in-vitro mixed lymphocyte-tissue-culture. Theimportance of polymorph leucocytes as scavenger cells hadbeen recognised for many years. By phase-contrast/time-lapsemicrophotography JAMES HIRSCH (New York) was able toillustrate the importance of leucocyte granules (protein-richlysosomes) in phagocytosis. Degranulation was a constantevent which led to digestion of engulfed bacteria. He had foundthat granules, harvested by disrupting leucocytes in sucrosesolution, were at a pH 5 and contained lyzozyme, phagocytin,ribonuclease, desoxyribonuclease, and acidphosphatase.ParaimmunoglobulinopathiesMalignant proliferation of the cells responsible for antibodyproduction results in several interesting clinical syndromes, ofwhich multiple myeloma is the prototype. These syndromesare usually associated with the appearance of paraimmuno-globulins in the serum andor Bence-Jones protein in the urine.ELLIOTT OSSERMAN (New York) preferred to group them asplasma-cell dyscrasias, an alternative to the term monoclonalimmunopathy used by Waldenstrom. The three diagnosticcriteria were the proliferation of immunologically competentplasma cells in the absence of an identifiable antigen stimulus,macroglobulinxmia, and circulating-antibody deficiency. Dis-eases other than multiple myelomatosis included plasma-cytoma, primary amyloidosis, Waldenstroms macroglobulin-xmia, non-reticular neoplasms associated with chronicinfection, and idiopathic plasma-cell dyscrasia. He recom-mended chlorambucil for the treatment of macroglobulinaemia.DANIEL BERGSAGEL (Toronto) recommended daily cyclo-phosphamide or intermittent courses of melphalan in thetreatment of multiple myelomatosis. The response wasparticularly favourable in those with type-K protein ratherthan type-L light-chain proteins. He would expect Bence-Jones proteinuria to be halved within three weeks; the abnormalserum-globulins to fall within 6 months; and some healing ofosteolytic lesions within a year in 10% of patients.Liver DiseaseSHEILA SHERLOCK (London) classified intrahepatic chole-stasis according to the sites of biliary secretory failure in theliver cells and intrahepatic bileduct system. The Dubin-Johnson type of conjugated hyperbilirubinasmia was probablydue to a genetically-determined intracellular defect. Drugssuch as norethandrolone, methyltestosterone, or oral contra-ceptives could cause a canalicular type of cholestasis, verysimilar to a type of benign intrahepatic obstructive jaundicecommonly seen in the last trimester of pregnancy in Scandi-navia and Chile. Cholestasis at a ductal or ductular level wasa feature of phenothiazine hypersensitivity, primary biliarycirrhosis, and sclerosing cholangitis.Protein DeficiencyJOHN BROCK (Cape Town) drew attention to the worldwideproblem of kwashiorkor caused by protein-calorie mal-nutrition. He preferred this term to protein malnutrition,because it emphasised the mutual interaction of energy-producing and other nutrients. He defined clearly the dominantrole of deficiency of a group of essential aminoacids in thextiology and pathogenesis of kwashiorkor.During the meeting Dr. Morvyn Williams, P.R.A.C.P., was admittedto honorary fellowship of the college. The meeting was addressedby two other honorary fellows: Prof. J. F. Brock; and Prof. SheilaSherlock, who is the first woman to be accorded this distinction.PHARMACOLOGICAL CONTROLOF BLOOD-PRESSUREFROM A CORRESPONDENTTHE annual scientific meeting of the Faculty of Anees-thetists of the Royal College of Surgeons on May 7 tookthe form of a symposium on the pharmacological control ofblood-pressure.Prof. J. H. BURN discussed the extent to which modernknowledge about the uptake of noradrenaline by sympatheticpost-ganglionic nerve-endings made it possible to interpret theconfused mass of experimental and clinical data concerning theelevation of blood-pressure by noradrenaline and its analogues.Infusion of noradrenaline at a high rate rapidly producedtachyphylaxis; yet ephedrine and mephentermine, which werebelieved to work by stimulating local release of noradrenalinefrom nerve terminals, became actually more effective aftertachyphylaxis to noradrenaline had been induced. Yet metara-minol, a drug with similar action, was still effective in raisingthe blood-pressure in reserpinised animals. No reasonablehypotheses emerged to explain these peculiar observations, butProfessor Burn suggested that the most effective method ofraising blood-pressure over a long period of time might be thesimultaneous use of both noradrenaline and one of the otherdrugs which act indirectly (such as mephentermine). Calciumwas as important for vascular smooth-muscle contraction as forcardiac contraction, and Professor Burn suggested that calciuminfusion might be tried as a last resort in case of severehypotension, especially after massive transfusion of citratedblood.Prof. W. S. PEART reviewed various examples of disturbedblood-pressure regulation, with special reference to the renin/angiotensin/aldosterone system, and its relationship to thesympathetic nervous system and catecholamines. He hadfound dialysis of value in lowering the blood-pressure in malig-nant hypertension unresponsive to other measures; and heconfirmed the findings of Kolff that in the desperate situationof uncontrollable hypertension and terminal renal failure,removal of the kidneys might permit good blood-pressurecontrol and make transplantation possible under more favour-able conditions. The normal kidney seemed to exert astabilising influence which prevented excessive swings ofblood-pressure with changes in plasma volume.Clues about the possible stabilising role of the kidneys wereprovided by Dr. M. R. LEE and Dr. R. L. HODGE, who describedwork on the mechanism of control of renin release. Dr. Leeillustrated the exquisite sensitivity of the rabbit to a smallgraded hsemorrhage, to which this animal responds by gradedrenin release, until the point is reached at which renal vaso-constriction is so severe that renin secretion-rate falls off.Moderately deep barbiturate anxsthesia did not affect reninconcentration. Abdominal operation, especially with tractionon the gut, seemed to be a provocative factor tending to causerenin release. Dr. Hodge showed a mechanism which mightbring this about. He and his colleagues had observed that thethreshold of renin secretion was capable of continuous modi-fication by renal vasomotor nerve activity. Carotid occlusion,which raised systemic arterial pressure, actually raised theangiotensin secretion-rate. Dr. Hodge pointed out that theaction of angiotensin was independent of sympathetic and blockade, and suggested that after removal of a phaeochromo-cytoma, carried out under full doses of these drugs, angiotensinwas the most effective pressor agent.There was general agreement that angiotensin, though a verypowerful pressor agent, had theoretical and probably practicaldangers in many situations. For control of hypertension duringanxsthesia small doses of hexamethonium seemed as satisfac-tory as any other method, and even in the presence ofphaeochromocytoma it seemed that the risks of small doses ofganglionic blocking drugs had been exaggerated.