Paul H. Harmon

Embolism by Air and Oxygen: Comparative Studies.

Attempts were made in these experiments to compare the minimal fatal dose of air and oxygen when introduced into a peripheral vein. Van Allen, Hrdina and Clarke 1 found that in embolism due to air introduced into the pulmonary vein, the rapidity of introduction of the air and the position of the animal were 2 factors of prime importance. The position of the animal was believed to be of importance by directing the flow of air upward by gravity. These authors found that when the head was uppermost, the air more easily produced death. In embolism due to introduction of air into a peripheral vein, the air goes first to the heart and lungs independent of the position of the animal. In the present studies, all animals were kept flat in the supine position during the injection of gas. The gas was injected quite rapidly; in most instances the entire amount being introduced in about 30 seconds. The minimal fatal dose of air was found to be about 8 cc. per kilo body weight. Animals under urethane anesthesia were used throughout the work. The air was injected through a large cannula into the femoral vein (usually the left) from an inverted burette, being forced in by a column of water. Another cannula was placed in the carotid artery to record the blood pressure. The air flowed in rapidly until at a certain point it began to flow more slowly and the column of water showed pulsations synchronous with the heart beat. This usually occurred when very roughly nine-tenths of the minimal fatal dose was injected. The results of 11 air injections are shown in Table 1.

Mechanism of Death in Bile Peritonitis

Conclusions The amount of plasma-like peritoneal exudate in experimental bile peritonitis indicates that the loss of this fluid from the blood stream is an important factor in the production of shock and death in this condition.

Experiments on the holding powers of various types of metallic internal fixation for transcervical fractures of the femur.

W HILE metalhc internal fixation for transcervica1 fracture of the femur has been in common use for more than fifteen years, it has only been during the Iast few years that a critica anaIysis of the resuIts has pointed out some of the factors that must be observed to obtain the best resuIts for each individua1 patient. It is generaIIy agreed that earIy contro1 of the patient by the surgeon, anatomic reduction, secure fixation and reguIar and proIonged postoperative supervision are required. Certain of the detaiIed steps of this program are stiI1 under discussion. No Iess than thirty different types of metallic fixation, more than fifty accessory gadgets for measuring, sighting, directing and pIacing the fixation materia1 and hundreds of articIes describing the use of these numerous and ingenious devices are found in the surgical Iiterature. No attempt wiI1 be made to cataIogue this knowIedge, but a safe conclusion to be drawn at this time is that the resuIts can still be improved. EarIy and exact reduction undoubtedly conserves the bIood suppIy which is so important in this fracture. MetaIIic fixation is to be regarded onIy as an efficient and temporary internal spIint to carry the patient over the period unti1 the fracture heaIs. Healing wiI1 be shorter the more efficient and the Iess destructive the type of interna fixation used and the Iess traumatic the technic of pIacing the fixation device. Absorption of the neck is due to excess motion during the heaIing period and since a11 non-viabIe materia1 produces pressure necrosis and Ioosens if sufficient strain is thrown upon it it is desirable to utilize the most efficient immobiIizing devices and to obtain the most stable reductions. It is diffrcuIt to segregate and anaIyze data in the human patient. However, the proof of several points appears now to be beyond question. Compere and WaIIace have furnished experimenta proof that early and accurate reduction Ieads to prompt union with a viable head. The same conclusions are inferred from the statistics of individual surgeons who have reported a high percentage of favorabIe results. The eIimination of shearing stress and its coroIIary, a stable reduction, has been pointed out by those who have given particular attention to the inclination of the fracture line (PauweIs, Eyre-Brook and Priddie and Linton) and by those who have advocated various types of osteotomies. WeIImerIing has pointed out the advantage of utilizing the thick cortical bone a short distance down the Iateral femoral shaft to hoId the internal fixation pin which is driven upward through the neck and head at as oblique an angle as possible. This assumes the use of Ionger fixation materials and their passage through the inferior third of the proximal femoral neck, a region where osseous trabeculae are best deveIoped. McEIveny pointed out that temporariIy increased Iongitudina1 traction accompanied by medial dispIacement of the lower fragment will often secure rotation of the head with a more horizonta1 and stabIe fracture line. It has been the experience of all surgeons that it is impossibIe to determine the time of secure osseous union in transcervial femoral

Experimental Freezing Bleeding Volume, General and Local Temperature Changes

Summary Experiments are reported to show that the bleeding volume is reduced in experimental freezing. General temperature studies in partially frozen animals were made and the low temperature of 25.7°C. (78°F.) reported in one instance. Local temperature studies were made to demonstrate the insulating function of living tissues.

Results from the treatment of sciatica due to lumbar disc protrusion

I N the past ten years surgical operations for protruded Iower lumbar intervertebral discs have become commonpIace. When it is recaIIed that prior to the present surgical era in the treatment of sciatica due to disc protrusions, severe permanent disability was unknown, the argument for conservative non-operative treatment becomes more IogicaI. On the other hand, proIonged tota disability of many months and varying degrees of residual back pain was experienced. Kirstein reported a foIIow-up study on two smaI1 groups of patients for a comparative anaIysis of the resuIts of nonoperative treatment versus partia1 disc removal. CompIete and permanent recovery from symptoms was four times as frequent in the operated group (48 per cent) as compared with the non-operated group (I 2.5 per cent). CoIonna and Friedenberg reported a simiIar study on twenty-eight patients who were not operated upon and on ninety-five patients subjected to partia1 disc excision. Seventy-one per cent of patients had residua1 pain in the unoperated group, as compared with onIy 40 per cent in the operative series. Neither group was unselected, which is aIso the case in the present study. Operations for disc protrusions are not inocuous, as both vascuIar and neuroIogic complications occur compIicating the conventiona posterior approach. At Ieast six grave injuries to the great vesseIs anterior to the vertebra1 bodies have been reported.22~27 Poppen and Ver Brugghen 44 have warned against the danger of producing a massive protrusion of disc substance with parapIegia by manipuIative procedures. In the past ten years, the author has seen nine cases of permanent parapIegia which have foIlowed “disc operations” performed elsewhere. As our knowIedge of a condition accumulates, it is often possibIe to set up ruIes of procedure for the treatment of specific cases seIected from the group. This paper wiI1 dea1 with a procedure for the seIection of cases for two types of operative treatment which is practiced in the Department of Orthopedic Surgery at the Permanente Hospitals. The aim is for as exact a diagnosis as possible folIowed by as simpIe a surgical procedure as possibIe which wiI1 yieId a Iong term resuIt for the patient.

Neutralization of the Virus of Poliomyelitis by Human Sera.

The investigations of Netter and Levaditi, 1 Anderson and Frost, 2 Peabody, Draper and Dochez, 3 and of Römer 4 among others indicate that the sera of persons who have recovered from an attack of poliomyelitis have the power to neutralize the virus of this disease. Netter and Levaditi 5 and Taylor 6 have shown that sera from this group of persons do not always possess this neutralizing power, however. The work of Anderson and Frost 2 and of Peabody, Draper and Dochez 3 and of Leake 7 indicates that sera from suspected “abortive” cases of poliomyelitis are not certain in their action against the virus. These 3 latter groups of observers have reported experiments in which sera of normal persons have sometimes neutralized the virus, although usually they did not. None of these investigators except Anderson and Frost, 2 who apparently nullified their results by the addition of “normal” human serum to activate the serum-virus mixtures, attempted to study these reactions in a quantitative manner. In the experiments reported here Berkefeld filtrates of 5% emulsion of spinal cord containing the virus were mixed in 1.5 cc. quantities with an equal quantity of the serum dilutions studied. The resulting mixture was placed in the incubator at 37°C. for 2 hours and then in the ice box for 18 to 20 hours. Two cc. amounts of the mixture were injected into monkeys by the intra-cerebral route. The experiments were planned so that they were controlled by the presence of convalescent sera from monkeys or persons which were expected to neutralize and by sera from infants or normal monkeys not expected to inactivate.

Bleeding Volume in Experimental Colon Bacillus Intoxication

Conclusions The shock state that follows intravenous injection of bacteria-free filtrâtes from the colon bacillus is classed as primary shock since the bleeding volume approximates that of the control animals.

Skin Tests for Sensitivity to Virus of Poliomyelitis

Early investigators 1 , 2 denied that the convalescent state in monkeys recovering from poliomyelitis was accompanied by cutaneous hyper-sensitiveness. Aycock 3 has stated that he has been unable to detect skin hypersensitiveness to monkey passage virus in human convalescents. Both Aycock and Kagan 4 and Stewart and Rhoads 5 while actively immunizing monkeys by the intracutaneous method, failed to note cutaneous allergic reactions. Recently, Jungeblut 6 has found that while cutaneous reactions of hypersensitiveness are lacking in convalescent monkeys, there is a high degree of generalized hypersensitiveness in these animals as judged by the occurrence of an immediate thermic response to the introduction of virus either intracerebrally or subcutaneously. Such a response was lacking in animals that had been uninfected. According to this author 7 the reverse situation obtains in man, as he observed a definite specific cutaneous reaction to an emulsion of virus-bearing monkey spinal cord in each of 27 human individuals with residual paralysis due to poliomyelitis. Sabin 8 has failed to find evidence of an allergic skin reaction in normal adults or in human convalescents either recent or of long standing, when tested with fresh heat inactivated preparations of monkey virus, human virus and normal monkey cord. Since one of us (J. A. H.) had prepared a concentrated and purified virus from which a large share of proteins, phospholipins and lecithins had been eliminated, we decided to test the cutaneous reactions of poliomyelitis convalescents with this product. Using a similarly prepared concentrate of normal monkey spinal cord as a control, we have carried out intradermal injections upon 17 children having residual paralysis from poliomyelitis. That none of these preparations contained viable virus was demonstrated by intracerebral injection of 1.0 cc. of both the concentrated ant1 uncorlcentrated virus into unused Macacus rlzesus monkeys by the intracerebral method.

Tests for the Blood-C.N.S. Barrier in Experimental Poliomyelitis.

It is well known that the mechanism regulating exchange between the blood and the central nervous system and spinal fluid is disturbed in all types of meningitis, allowing both normal blood constituents and foreign substances to pass into the spinal fluid (reviewed by Katzenellenbogen 1 ). While a “meningeal stage”has been described in poliomyelitis, the origin of the cells in the subarachnoid spaces appears to be from the perivascular spaces of the medullary substance. This communication will give the results of several tests of the blood central nervous system barrier in experimental poliomyelitis. Such findings have a bearing on specific treatment, since a gross barrier defect would allow free passage of neutralizing substances from blood into the medullary substance and spinal fluid. Flexner and Amoss 2 while showing that the virus did not regularly pass from the blood to the nervous system, suggested that a defect in the barrier might be of importance in the natural pathogenesis of this disease in man. The failure to find virus-neutralizing substances in the spinal fluid of man during convalescence, 3 although these substances are present in the blood of a large number of human convalescents even during and prior to paralysis, 4 could be explained by an intact barrier. In testing the barrier in experimental poliomyelitis with several types of antibodies, Shaughnessy, Grubb and Harmon 5 showed that none of these substances, except diphtheria antitoxin, passed from the blood into either the spinal cord or the spinal fluid. In the clinic, Flatau 6 found the barrier impermeable to acid fuchsin. The value of this latter observation is not great as the stage of the disease was not stated.

Depressor Extracts of Some Human Tissues.

Conclusion In several human tissue extracts, including toxic thyroid tissue and carcinomatous tissue, depressor substances were found not to be present in unusual amounts. The major part of the depressor substance present in these tissue extracts does not acr like acetylcholine or histamine when tested for effect on the blood pressure of atropinized rabbits.