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LACTATE DEHYDROGENASE MULTIPLICITY IN NORMAL AND DISEASED HUMAN MUSCLE
433
Campbell et all described the remarkable incidence of disseminated sclerosis in a group of people working with swayback, I am now repeating the sheep work, but this time making allowance for copper deficiency as a possible accessory factor. M.R.C. Research Group
on
Demyelinating Diseases, University of Durham, Newcastle upon Tyne.
E. J. FIELD.
SMALLPOX VACCINATION
SIR,-Professor Saunders (Feb. 3) expressed interest experience of other vaccinators who followed his
in the
advice.7 Two of my colleagues, Dr. J. C. Evans and Dr. Alice McEvett, and I recently vaccinated over 2000 persons. Like others we were restricted in vaccine supplies. We therefore used a rubber bulb to expel the vaccine, and with practice found it possible to vaccinate up to 80 persons with a singledose tube. 88% of our patients returned for subsequent inspection, and over 98% of these were found to have had a successful
vaccination. Health Physics and Medical Division, Atomic Energy Research Establishment, Harwell, near Didcot, Berks.
R. G. ORR.
EXTERNAL CARDIAC MASSAGE SIR, The following case of " closed " cardiac massage is reported because of current interest in the technique, and because it converted a former sceptic-myself. The patient was a 33-year-old woman undergoing stripping of varicose veins. Towards the end of the operation, an intense and quite intractable respiratory spasm developed. Cyanosis deepened over about ten or fifteen minutes; finally it was replaced by corpse-like lividity, and the peripheral pulses and heart-sounds disappeared. It was decided to give closed cardiac compression a trial before opening the chest. Using both hands superimposed, the lower part of the breastbone was forcibly " bounced " inwards at a rate of about 70 per minute. After a short delay, a good radial pulse was felt, in time with the massage; it stopped when the massage was stopped and started again when massage was restored. This was checked independently by two observers. Within about three minutes there were a few spontaneous breaths. The rhythmic squeezing of the chest seemed also to be causing some ventilation. The colour improved rapidly, and now on stopping the compression a regular heart-beat continued. The operation was completed and was followed by a normal recovery. The criterion of effective massage of the heart is that it shall artificially maintain an adequate circulation. That criterion was fulfilled here as efficiently as could have been hoped for by a thoracotomy. Although the stimulus of a single blow on the precordium will sometimes start an arrested heart, it was evident here that the circulation was maintained rather than merely triggered by the compression. It is interesting that there wasa short delay before the massage was fully effective; possibly the thoracic cage has first to be " softened up " to allow sufficient squeezing of the heart. The ease and ready applicability of the method were impressive. Possibly the greatest single advantage of closed cardiac massage is that it avoids the psychological hurdle of thoracotomy, and so is likely to be used more freely. E. G. HARDY. Chester.
SiR,—The letters
this subject prompt me to draw 1955 article8 on Critical Evaluation of Synon
attention to a cardial Massage. 6 7. 8.
Campbell, A. M. G., Daniel, P., Porter, J. R., Russell, W. R., Smith, H. V., Innes, J. R. M. Brain, 1947, 70, 50. Lancet, 1958, i, 1382. Belcher, E. H., Wand-Tetley, J. I. Ann. phys. Med. 1955, 2, 207.
A more elaborate machine than the one designed by Dr. A. W. Warltier (Feb. 10) was described last year by J. H. Rand and C. S. Beck.9 A block of hard sponge rubber descends on the sternum every second exerting a pressure of 60-90 lb. with each impact; oxygen is given by a face mask and there is also a built-in defibrillator. It has been suggested that this machine be used also by rescue squads and at the boxing ring. London,
S.W.3.
NEVILLE LESLIE YHAP.
POTENCY CONTROL OF SALK VACCINE SiR,—Your annotation 10 calls attention to Beale’s fine study of the agar-gel precipitation test for the D-antigen and also to the need for more satisfactory control of the potency of the vaccine. The immunogenic potency of Salk vaccine has been measured by the quantitative neutralising-antibody-combining (N.A.C.) test.ll This in-vitro test is rapidly carried out and has been found to be far more reproducible than the animal potency test. As indicated in your note, an essential feature of any potency test is a direct and simultaneous comparison with reference vaccine, and this is a cardinal feature of the N.A.C. test.
Baylor University College of Medicine, Texas Medical Center, Houston, Texas.
JOSEPH L. MELNICK.
LACTATE DEHYDROGENASE MULTIPLICITY IN NORMAL AND DISEASED HUMAN MUSCLE
SIR,-van der Helm 12 described a histochemical procedure for the detection of lactate dehydrogenase (L.D.H.) activity after fractionation in an agar gel. Working on the subject of L.D.H. multiplicity for some time (though with another technique 13-15), we applied the van der Helm procedure and obtained very good results. We used a substrate solution identical to that he proposed. Nitro-blue tetrazolium of Sigma (St. Louis) origin gave us the most intense stains. One modification was made: the substrate solution was stabilised in a second agar layer freshly poured on the enzyme layer after electrophoresis; this procedure proved superior if a large range of L.D.H. activities was to be covered. After incubation for 60 minutes, the double agar plate was fixed, dried, and scanned. Percentages between zones of L.D.H. activity were then calculated. With this method, we studied the L.D.H. pattern of normal and diseased human skeletal muscle (biopsy specimens). In 5 normal controls the following percentages were found for the five L.D.H. fractions (L.D.H.refers to tthe most rapid and L.D.H.5 to the slowest fraction): L.D.H.l 8-7%, L.D.H.2 16.1%, L.D.H.3 197%, L.D.H.4 2411%, L.D.H.5 314%, with 25-9% and 38 5% as extreme values for L.D.H.5. In primary muscular dystrophy (5 patients) and secondary atrophy due to neurological trauma (5 patients), the mean values were as follows: L.D.H.l 177%, L.D.H.2 22-4%, L.D.H.3 224%, L.D.H.4 197%, L.D.H.5 17-7%, with 3-3% and 26-8% as extreme values for L.D.H.5. Thus a modification in the L.D.H. pattern was found in all pathological cases: L.D.H.5 tends to decrease relative to the other fractions. In 2 patients with muscular dystrophy L.D.H.5 accounted for only 3-3% and 5-8% of total L.D.H. activity. The impression is that diseased muscle loses its original L.D.H. pattern; the phenomenon could thus be described as dedifferentiation. Our object is to draw attention to this phenomenon and also to advocate the use of the easily applied van der Helm technique. 9. Med. Tribune, 1961, 2, no. 33. 10. Lancet, 1961, ii, 1185. 11. Benyesh-Melnick, M.,Melnick,J. L. Bull. Wld Hlth Org. 1959, 20, 1075. 12. van der Helm, H. J. Lancet, 1961, ii, 108. 13. Wieme, R. J. in Protides of the Biological Fluids; p. 236. Amsterdam, 1959. (Proceedings of the 6th Collo-Opium, Bruges, 1958). 14. Wieme, R. J., Demeulenaere, L. Acta gastro-enterol. belg. 1959, 22, 69. 15. Wieme, R. J. Studies on Agar Gel Electrophoresis; p. 482. Brussels,
1959.
434 In our study we examined biopsy fragments of about 10 mg. fresh weight, homogenised in twice their volume of distilled water and centrifuged for 10 minutes at 10,000 g. But useful results can be obtained simply by pushing fresh tissue specimens of about 1 mg. weight directly into the agar gel. Since changes are usually pronounced, a visual estimate can give a rough impression of the L.D.H. pattern of the specimen, if scanning devices are not at hand.
INFLUENCE OF RAPID INTRAVENOUS INJECTION OF PROTAMINE OR HEXADIMETHRINE ON PULMONARY-ARTERY PRESSURE AND SYSTEMIC PRESSURE
We are preparing a paper on the correlation of these findings with clinical history, biopsy specimens, and changes in serum-phosphate level after glucose administration. R. J. WIEME Laboratory of the Medical Clinic, University of Ghent,
Belgium.
M.
J. LAURYSSENS.
HYPOTENSIVE ACTION OF PROTAMINE AND HEXADIMETHRINE
SIR,-Referring to the article by Dr. Egerton and Dr. Robinson,! we should like to summarise the results of our study of the mechanism of the blood-pressure drop after rapid intravenous or intra-arterial injection of protamine sulphate or hexadimethrine bromide (’Polybrene ’) in non-heparinised dogs. Besides their hypotensive and anticoagulant actions, both and hexadimethrine have other undesirable sideeffects. In vitro, in high concentrations, both drugs precipitate fibrinogen 23 and enhance the clotting of plasma by thrombin, probably by influencing the polymerisation phase.4 Hexadimethrine, like protamine sulphate, has been found to agglutinate red blood-cells.5 6After rapid intravenous injection, protamine sulphate produces thrombocytopenia, leucopenia, 1and, in high doses, diminution of the fibrinogen level.9 Injection of hexadimethrine also has a thrombocytopenic effect.1o Our experiments were performed on .adult mongrel dogs, weighing 8-12 kg., which were anaesthetised by intravenous pentobarbitone. Passive lung ventilation was maintained by endotracheal intubation and an automatic respirator. A median thoracotomy was performed. The blood-pressures in the aorta and pulmonary artery were simultaneously recorded by cannulx filled with heparinised isotonic saline, introduced through the femoral artery and the right atrium respectively. The systemic blood-pressure was measured with a mercury manometer and the pulmonary-artery pressure with a water
protamine
manometer.
The baseline and protamine
blood-pressure was recorded for ten minutes, sulphate (Eli Lilly) or hexadimethrine (polybrene, Abbott) was injected rapidly into an exposed femoral vein (2-5, 5, or 10 mg. per kg.). Both drugs produced, within 4-5 seconds, a steep rise in the pulmonary-artery pressure, followed immediately by a drop in the systemic arterial pressure. The extent of these pressure changes was directly proportional to the dosage. There were no apparent quantitative differences between the protamine sulphate and hexadimethrine (see table). After 2-15 minutes, according to the amount injected, both blood-pressures had returned progressively and simultaneously to normal. Occasionally, bradycardia accompanied the initial rise in pulmonary-artery pressure. Because of the automatic respiration, gross changes in depth and frequency of respiration were prevented. After injection of protamine sulphate or hexadimethrine into the femoral artery, the rise in pulmonary pressure and the drop in systemic pressure were less pronounced. The time between the injection and the pressure changes was slightly longer10-20 seconds. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Egerton, W. S., Robinson, C. L. N. Lancet, 1961, ii, 635. Mylon, E., Winternitz, M. C., de Suto-Nagy, G. J. J. biol. Chem. 1942, 143, 21. Godal, H. C. Scand. J. clin. Lab. Invest. 1960, 12, 433. Godal, H. C. ibid. p. 446. Shelley, W. B., Hodgkins, M. P., Visscher, M. B. Proc. Soc. exp. Biol., N. Y. 1942, 50, 300. Lalezari, P., Spaet, T. H. J. Lab. clin Med. 1961, 57, 868. Thompson, W. H. Z. physiol Chem. 1900, 29, 1. Jaques, L. B. Brit. J. Pharmacol. 1949, 4, 135. Holemans, R., Vermylen, C., Verstraete, M. Med. Exper. 1960, 2, 294. Weiss, W. A., Gilman, J. S., Catenacci, A. J., Osterberg, A. E. J. Amer. med. Ass. 1958, 166, 603.
protamine sulphate and hexadimethrine caused thrombopenia and reduced the number of peripheral leucocytes. At doses higher than 5 mg. per kg. in most animals, a decrease in the circulating fibrinogen was usually observed with protamine sulphate; a dose of 10 mg. per kg. of hexadimethrine produced a detectable decrease in fibrinogen. Repetition of the intravenous or intra-arterial injection of protamine sulphate or hexadimethrine, after the blood-pressure had returned to normal, reproduced the changes in bloodA diminution of pressure and in platelets and leucocytes. fibrinogen level was more often noted for both drugs. We then studied lung biopsies before and after intravenous injection of protamine sulphate or hexadimethrine to see whether the obstructing effect of these drugs on the pulmonary vascular bed was related to their thrombocytopenic, leucopenic, fibrinogen-precipitating, and haemagglutinating properties. After protamine sulphate (10 mg. per kg.), agglutinates of white blood cells, platelets, and protein precipitate could be seen obstructing small arteriolar branches and capillaries. There was also a definite impression of a stronger agglutination of red cells within the pulmonary vessels after injection of the drug. After an equal dose of hexadimethrine, the changes were Both marked
similar but less evident.
Our results strongly suggest that a partial mechanical obstruction of the pulmonary capillary bed by agglutinated blood-cells and precipitated protein, probably mainly fibrinogen, is mainly responsible for the systemic hypotension, by decreasing the left cardiac output. The spontaneous reversal of the pulmonary hypertension can be explained by the opening of additional vascular channels, abolition of an eventual concomitant vasoconstriction, or forcing of the obstructing material through the vessels. The release of serotonin (5-hydroxytryptamine) from aggregated platelets could also contribute to the blood-pressure changes by constricting the pulmonary vessels." The less pronounced histological findings after injection of hexadimethrine could be accounted for by the weaker fibrinogen-precipitating effect of protamine.4 Extensive vasodilatation of the muscle arterioles, as suggested by Jaques8 to explain the shock after injection of protamine, can be an accompanying phenomenon or can result from the pressure changes; but it cannot be assumed to be the primary cause. This is also illustrated by the results of Egerton and Robinson,1 who found only a slight vasodilatation in the first minute after hexadimethrine injection. Our hypothesis is supported by some observations in the literature.
Shelley et awl. found that the addition of salmine sulphate stopped the flow of whole dog blood through an isolated organ, whereas addition of salmine sulphate to dog serum, while perfusing an isolated organ, did not affect the perfusion-rate. In rabbits, the injection of protamine caused no significant fall in blood-pressure or decrease in circulating platelets 8; nor did it produce gross agglutination of rabbit red cells in vitro, 11.
Haddy,
F. J.
Angiology, 1960, 11,
21.
Campbell et all described the remarkable incidence of disseminated sclerosis in a group of people working with swayback, I am now repeating the sheep work, but this time making allowance for copper deficiency as a possible accessory factor. M.R.C. Research Group
on
Demyelinating Diseases, University of Durham, Newcastle upon Tyne.
E. J. FIELD.
SMALLPOX VACCINATION
SIR,-Professor Saunders (Feb. 3) expressed interest experience of other vaccinators who followed his
in the
advice.7 Two of my colleagues, Dr. J. C. Evans and Dr. Alice McEvett, and I recently vaccinated over 2000 persons. Like others we were restricted in vaccine supplies. We therefore used a rubber bulb to expel the vaccine, and with practice found it possible to vaccinate up to 80 persons with a singledose tube. 88% of our patients returned for subsequent inspection, and over 98% of these were found to have had a successful
vaccination. Health Physics and Medical Division, Atomic Energy Research Establishment, Harwell, near Didcot, Berks.
R. G. ORR.
EXTERNAL CARDIAC MASSAGE SIR, The following case of " closed " cardiac massage is reported because of current interest in the technique, and because it converted a former sceptic-myself. The patient was a 33-year-old woman undergoing stripping of varicose veins. Towards the end of the operation, an intense and quite intractable respiratory spasm developed. Cyanosis deepened over about ten or fifteen minutes; finally it was replaced by corpse-like lividity, and the peripheral pulses and heart-sounds disappeared. It was decided to give closed cardiac compression a trial before opening the chest. Using both hands superimposed, the lower part of the breastbone was forcibly " bounced " inwards at a rate of about 70 per minute. After a short delay, a good radial pulse was felt, in time with the massage; it stopped when the massage was stopped and started again when massage was restored. This was checked independently by two observers. Within about three minutes there were a few spontaneous breaths. The rhythmic squeezing of the chest seemed also to be causing some ventilation. The colour improved rapidly, and now on stopping the compression a regular heart-beat continued. The operation was completed and was followed by a normal recovery. The criterion of effective massage of the heart is that it shall artificially maintain an adequate circulation. That criterion was fulfilled here as efficiently as could have been hoped for by a thoracotomy. Although the stimulus of a single blow on the precordium will sometimes start an arrested heart, it was evident here that the circulation was maintained rather than merely triggered by the compression. It is interesting that there wasa short delay before the massage was fully effective; possibly the thoracic cage has first to be " softened up " to allow sufficient squeezing of the heart. The ease and ready applicability of the method were impressive. Possibly the greatest single advantage of closed cardiac massage is that it avoids the psychological hurdle of thoracotomy, and so is likely to be used more freely. E. G. HARDY. Chester.
SiR,—The letters
this subject prompt me to draw 1955 article8 on Critical Evaluation of Synon
attention to a cardial Massage. 6 7. 8.
Campbell, A. M. G., Daniel, P., Porter, J. R., Russell, W. R., Smith, H. V., Innes, J. R. M. Brain, 1947, 70, 50. Lancet, 1958, i, 1382. Belcher, E. H., Wand-Tetley, J. I. Ann. phys. Med. 1955, 2, 207.
A more elaborate machine than the one designed by Dr. A. W. Warltier (Feb. 10) was described last year by J. H. Rand and C. S. Beck.9 A block of hard sponge rubber descends on the sternum every second exerting a pressure of 60-90 lb. with each impact; oxygen is given by a face mask and there is also a built-in defibrillator. It has been suggested that this machine be used also by rescue squads and at the boxing ring. London,
S.W.3.
NEVILLE LESLIE YHAP.
POTENCY CONTROL OF SALK VACCINE SiR,—Your annotation 10 calls attention to Beale’s fine study of the agar-gel precipitation test for the D-antigen and also to the need for more satisfactory control of the potency of the vaccine. The immunogenic potency of Salk vaccine has been measured by the quantitative neutralising-antibody-combining (N.A.C.) test.ll This in-vitro test is rapidly carried out and has been found to be far more reproducible than the animal potency test. As indicated in your note, an essential feature of any potency test is a direct and simultaneous comparison with reference vaccine, and this is a cardinal feature of the N.A.C. test.
Baylor University College of Medicine, Texas Medical Center, Houston, Texas.
JOSEPH L. MELNICK.
LACTATE DEHYDROGENASE MULTIPLICITY IN NORMAL AND DISEASED HUMAN MUSCLE
SIR,-van der Helm 12 described a histochemical procedure for the detection of lactate dehydrogenase (L.D.H.) activity after fractionation in an agar gel. Working on the subject of L.D.H. multiplicity for some time (though with another technique 13-15), we applied the van der Helm procedure and obtained very good results. We used a substrate solution identical to that he proposed. Nitro-blue tetrazolium of Sigma (St. Louis) origin gave us the most intense stains. One modification was made: the substrate solution was stabilised in a second agar layer freshly poured on the enzyme layer after electrophoresis; this procedure proved superior if a large range of L.D.H. activities was to be covered. After incubation for 60 minutes, the double agar plate was fixed, dried, and scanned. Percentages between zones of L.D.H. activity were then calculated. With this method, we studied the L.D.H. pattern of normal and diseased human skeletal muscle (biopsy specimens). In 5 normal controls the following percentages were found for the five L.D.H. fractions (L.D.H.refers to tthe most rapid and L.D.H.5 to the slowest fraction): L.D.H.l 8-7%, L.D.H.2 16.1%, L.D.H.3 197%, L.D.H.4 2411%, L.D.H.5 314%, with 25-9% and 38 5% as extreme values for L.D.H.5. In primary muscular dystrophy (5 patients) and secondary atrophy due to neurological trauma (5 patients), the mean values were as follows: L.D.H.l 177%, L.D.H.2 22-4%, L.D.H.3 224%, L.D.H.4 197%, L.D.H.5 17-7%, with 3-3% and 26-8% as extreme values for L.D.H.5. Thus a modification in the L.D.H. pattern was found in all pathological cases: L.D.H.5 tends to decrease relative to the other fractions. In 2 patients with muscular dystrophy L.D.H.5 accounted for only 3-3% and 5-8% of total L.D.H. activity. The impression is that diseased muscle loses its original L.D.H. pattern; the phenomenon could thus be described as dedifferentiation. Our object is to draw attention to this phenomenon and also to advocate the use of the easily applied van der Helm technique. 9. Med. Tribune, 1961, 2, no. 33. 10. Lancet, 1961, ii, 1185. 11. Benyesh-Melnick, M.,Melnick,J. L. Bull. Wld Hlth Org. 1959, 20, 1075. 12. van der Helm, H. J. Lancet, 1961, ii, 108. 13. Wieme, R. J. in Protides of the Biological Fluids; p. 236. Amsterdam, 1959. (Proceedings of the 6th Collo-Opium, Bruges, 1958). 14. Wieme, R. J., Demeulenaere, L. Acta gastro-enterol. belg. 1959, 22, 69. 15. Wieme, R. J. Studies on Agar Gel Electrophoresis; p. 482. Brussels,
1959.
434 In our study we examined biopsy fragments of about 10 mg. fresh weight, homogenised in twice their volume of distilled water and centrifuged for 10 minutes at 10,000 g. But useful results can be obtained simply by pushing fresh tissue specimens of about 1 mg. weight directly into the agar gel. Since changes are usually pronounced, a visual estimate can give a rough impression of the L.D.H. pattern of the specimen, if scanning devices are not at hand.
INFLUENCE OF RAPID INTRAVENOUS INJECTION OF PROTAMINE OR HEXADIMETHRINE ON PULMONARY-ARTERY PRESSURE AND SYSTEMIC PRESSURE
We are preparing a paper on the correlation of these findings with clinical history, biopsy specimens, and changes in serum-phosphate level after glucose administration. R. J. WIEME Laboratory of the Medical Clinic, University of Ghent,
Belgium.
M.
J. LAURYSSENS.
HYPOTENSIVE ACTION OF PROTAMINE AND HEXADIMETHRINE
SIR,-Referring to the article by Dr. Egerton and Dr. Robinson,! we should like to summarise the results of our study of the mechanism of the blood-pressure drop after rapid intravenous or intra-arterial injection of protamine sulphate or hexadimethrine bromide (’Polybrene ’) in non-heparinised dogs. Besides their hypotensive and anticoagulant actions, both and hexadimethrine have other undesirable sideeffects. In vitro, in high concentrations, both drugs precipitate fibrinogen 23 and enhance the clotting of plasma by thrombin, probably by influencing the polymerisation phase.4 Hexadimethrine, like protamine sulphate, has been found to agglutinate red blood-cells.5 6After rapid intravenous injection, protamine sulphate produces thrombocytopenia, leucopenia, 1and, in high doses, diminution of the fibrinogen level.9 Injection of hexadimethrine also has a thrombocytopenic effect.1o Our experiments were performed on .adult mongrel dogs, weighing 8-12 kg., which were anaesthetised by intravenous pentobarbitone. Passive lung ventilation was maintained by endotracheal intubation and an automatic respirator. A median thoracotomy was performed. The blood-pressures in the aorta and pulmonary artery were simultaneously recorded by cannulx filled with heparinised isotonic saline, introduced through the femoral artery and the right atrium respectively. The systemic blood-pressure was measured with a mercury manometer and the pulmonary-artery pressure with a water
protamine
manometer.
The baseline and protamine
blood-pressure was recorded for ten minutes, sulphate (Eli Lilly) or hexadimethrine (polybrene, Abbott) was injected rapidly into an exposed femoral vein (2-5, 5, or 10 mg. per kg.). Both drugs produced, within 4-5 seconds, a steep rise in the pulmonary-artery pressure, followed immediately by a drop in the systemic arterial pressure. The extent of these pressure changes was directly proportional to the dosage. There were no apparent quantitative differences between the protamine sulphate and hexadimethrine (see table). After 2-15 minutes, according to the amount injected, both blood-pressures had returned progressively and simultaneously to normal. Occasionally, bradycardia accompanied the initial rise in pulmonary-artery pressure. Because of the automatic respiration, gross changes in depth and frequency of respiration were prevented. After injection of protamine sulphate or hexadimethrine into the femoral artery, the rise in pulmonary pressure and the drop in systemic pressure were less pronounced. The time between the injection and the pressure changes was slightly longer10-20 seconds. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Egerton, W. S., Robinson, C. L. N. Lancet, 1961, ii, 635. Mylon, E., Winternitz, M. C., de Suto-Nagy, G. J. J. biol. Chem. 1942, 143, 21. Godal, H. C. Scand. J. clin. Lab. Invest. 1960, 12, 433. Godal, H. C. ibid. p. 446. Shelley, W. B., Hodgkins, M. P., Visscher, M. B. Proc. Soc. exp. Biol., N. Y. 1942, 50, 300. Lalezari, P., Spaet, T. H. J. Lab. clin Med. 1961, 57, 868. Thompson, W. H. Z. physiol Chem. 1900, 29, 1. Jaques, L. B. Brit. J. Pharmacol. 1949, 4, 135. Holemans, R., Vermylen, C., Verstraete, M. Med. Exper. 1960, 2, 294. Weiss, W. A., Gilman, J. S., Catenacci, A. J., Osterberg, A. E. J. Amer. med. Ass. 1958, 166, 603.
protamine sulphate and hexadimethrine caused thrombopenia and reduced the number of peripheral leucocytes. At doses higher than 5 mg. per kg. in most animals, a decrease in the circulating fibrinogen was usually observed with protamine sulphate; a dose of 10 mg. per kg. of hexadimethrine produced a detectable decrease in fibrinogen. Repetition of the intravenous or intra-arterial injection of protamine sulphate or hexadimethrine, after the blood-pressure had returned to normal, reproduced the changes in bloodA diminution of pressure and in platelets and leucocytes. fibrinogen level was more often noted for both drugs. We then studied lung biopsies before and after intravenous injection of protamine sulphate or hexadimethrine to see whether the obstructing effect of these drugs on the pulmonary vascular bed was related to their thrombocytopenic, leucopenic, fibrinogen-precipitating, and haemagglutinating properties. After protamine sulphate (10 mg. per kg.), agglutinates of white blood cells, platelets, and protein precipitate could be seen obstructing small arteriolar branches and capillaries. There was also a definite impression of a stronger agglutination of red cells within the pulmonary vessels after injection of the drug. After an equal dose of hexadimethrine, the changes were Both marked
similar but less evident.
Our results strongly suggest that a partial mechanical obstruction of the pulmonary capillary bed by agglutinated blood-cells and precipitated protein, probably mainly fibrinogen, is mainly responsible for the systemic hypotension, by decreasing the left cardiac output. The spontaneous reversal of the pulmonary hypertension can be explained by the opening of additional vascular channels, abolition of an eventual concomitant vasoconstriction, or forcing of the obstructing material through the vessels. The release of serotonin (5-hydroxytryptamine) from aggregated platelets could also contribute to the blood-pressure changes by constricting the pulmonary vessels." The less pronounced histological findings after injection of hexadimethrine could be accounted for by the weaker fibrinogen-precipitating effect of protamine.4 Extensive vasodilatation of the muscle arterioles, as suggested by Jaques8 to explain the shock after injection of protamine, can be an accompanying phenomenon or can result from the pressure changes; but it cannot be assumed to be the primary cause. This is also illustrated by the results of Egerton and Robinson,1 who found only a slight vasodilatation in the first minute after hexadimethrine injection. Our hypothesis is supported by some observations in the literature.
Shelley et awl. found that the addition of salmine sulphate stopped the flow of whole dog blood through an isolated organ, whereas addition of salmine sulphate to dog serum, while perfusing an isolated organ, did not affect the perfusion-rate. In rabbits, the injection of protamine caused no significant fall in blood-pressure or decrease in circulating platelets 8; nor did it produce gross agglutination of rabbit red cells in vitro, 11.
Haddy,
F. J.
Angiology, 1960, 11,
21.