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A new performed, semi-rigid, polyethylene catheter, with built-in torque control, has been devised for entry to the pulmonary artery in complete transposition of the great arteries. It has been used 19 times in 17 patients: 18 times the pulmonary artery was entered from the right atrium (via the left atrium and ventricle) in a time between 40 s and 15 min (median 5 min); the patients' ages were 2 days to 6 years (median 8 months) and their weights were 3.1 to 13.3 kg (median 6.9 (kg: in the remaining 1 day-old patient, the procedures was terminated because of atrial flutter. The catheter was introduced into the axillary vein in 3 patients and thesaphenous or femoral vein in the remainder. It is suitable for angiocardiography, and the other heart chambers and vessels were easily entered. Thus the catheter has certain advantages over previously described methods for entry to the pulmonary artery, particularly when there is inferior vena caval thrombosis, or when angiocardiography is necessary. Its use does depend on the presence of an interatrial communication, so a method for entry to the pulmonary artery by retrograde catheterization from the axillary artery using a different catheter is also presented; this was successful in 2 patients with ventriculal sepatal defect.

A 22-year-old man suffered a stab wound of the femoral artery and vein. This was followed by disseminated intravascular coagulation. Renal failure then occurred presumably due to fibrin deposition in the small vessels of the kidney. The D.I.C. was successfully treated with heparin and the renal failure with peritoneal dialysis. It is suggested that D.I.C. and consequent alterations in regional blood flow following trauma are not uncommon, and search should be made for these phenomena in every case of major trauma.

The various artefacts that may be encountered in phlebograms and which may be confused with thrombus are described. Methods of avoiding these pitfalls are discussed. the conclusions are based on over 2500 phlebograms carried out for suspected deep vein thrombosis.

In New Zealand rabbits pulses of pressure (seventy millimeters of mercury at two-second intervals) applied by a pneumatic tourniquet placed about the leg and connected to an animal respirator consistently increased femoral nutrient vein blood flow 16 to 150 per cent when the pulses were superimposed on an ambient pressure of five millimeters of mercury, while the same pulses superimposed on an ambient pressure of twenty millimeters of mercury consistently reduced blood flow 25 to 59 per cent.

1. In order to obtain information about production and activity of the "sleep factor delta", characterized as oligopeptide with MW approximately 860, the peptide concentration (in nM/g dry dialysate) and the EEG delta activity of the corresponding dialysate (delta percent and integral of delta increase) were determined for cerebral blood from the dural venous sinus, systemic blood from the femoral vein and cerebrospinal fluid (CSF) from sleeping and alert rabbit donors. 2. Before hypnogenic or walking stimulation all hemodialysates exhibit a basic peptide concentration (26 nM/g dry dialysate) and a corresponding basic delta activity (231 muV X sec delta integral within 6 sec). 3. The electric thalamic stimulation of donors, with parameters inducing orthodox delta-sleep, parallely increases the delta peptide concentration (160 nM/g) and its activity (543 muV X sec delta integral) in cerebral blood dialysate. 4. The cerebral blood plasma dialyzed in vitro after hypnogenic thalamic stimulation exhibits a still higher peptide concentration (197 nM/g) and delta activity (804 muV X sec), increased at will by using a steeper diffusion gradient in the dialyzer (possibility of extracting more peptide). 5. By contrast, the systemic femoral blood plasma, similarly dialyzed in vitro develops a weaker delta activity (646 muV X sec) than cerebral blood plasma, in spite of a higher peptide concentration (275 nM/g). This dissociation suggests an activity marked by concomittant waking factors added to the cerebral blood during passage through the hindlimbs musculature. 6. The fact that cerebral blood dialyzed in vivo in walking donors has no delta activity (-313 muV X sec) in spite of a minimal delta peptide concentration (10 nM/g) confirms the assumption that walking factors may mask the peptide activity. Additionally, it shows that they may also antagonize the peptide production. The sleep cycle seems to be regulated not only by neural, rapid acting antagonistic mechanisms, but also by humoral, slower acting antagonistic factors. 7. Cerebrospinal fluid withdrawn from sleeping donors induces insignificant changes in recipients, probably because of too small a peptide concentration in this fluid.

The present study was undertaken to determine the involvement of cardiac lysosomes in injury to the myocardium after cardiopulmonary bypass. Twenty conditioned mongrel dogs, weighing 15 to 18 kilograms, were fasted overnight, anesthetized with sodium pentobarbital (30 mg. per kilogram), intubated, and maintained on positive-pressure ventilation. The femoral artery and femoral vein were cannulated for pressure measurements. After median sternotomy, intravenous heparin was administered (3 mg. per kilogram) before the aorta and the superior and inferior venae cavae were cannulated for bypass. Bypass was instituted with a Travenol modular pump and a Bentley pediatric bubble oxygenator and heat exchanger. The ultrastructural effects on the myocardium and the acid phosphatase activity in the left ventricle were compared in dogs exposed to bypass for 1 hour with varying types of myocardial support: perfusion of the coronary arteries, normothermic ischemic arrest, or selective cardiac hypothermia. The morphology of control hearts and hearts fixed after 1 hour of coronary perfusion were similar. The distribution and structure of subcellular lysosomes were the same and showed identical patterns of acid phosphatase activity. Normothermic ischemic arrest was associated with a loss of glycogen stores, disrupted sarcoplasmic reticulum and T tubules, vacuolization and decrease in matrix density of mitochondria, and separation of the intercalated discs. Lysosomal activity was absent except for occasional residual bodies in the nuclear pole zone of the myocardial cells. Selective cardiac hypothermia produced results superior to those from normothermic ischemic arrest. Although these hearts showed proliferation of the lysosomal compartment, the organelles responsible for excitation-contraction coupling were spared.

Catecholamine concentrations were determined in left spermatic vein blood of 18 patients with varicocele. These values were compared with concentrations of catecholamines in the right femoral vein. Of 18 patients studied, 6 had moderate to marked elevations of spermatic vein catecholamine concentrations. Norepinephrine was the fractioned component that was elevated. In an average 1-year follow-up the group with elevated catecholamine levels had a much better semen improvement percentage and pregnancy rate than the other group. Chronic exposure of testicular vasculature to norepinephrine may account for the spermatogenic dysfunction encountered in varicocele patients. Once this exposure is interrupted, there may be reversibility of function and the fertility prognosis may improve. The presence of other adrenal or renal metabolites detrimental to spermatogenesis must be considered.

Bei 63 Patienten wurden Funktionsszintigramme des Herzens mit unterschiedlicher Injektionstechnik und zwei verschiedenen Radiopharmaka (99mTc-Pertechnetat und 99mTc-Human-Serum-Albumin) verglichen. Dabei erwies sich die Injektion von 99mTc-Human-Serum-Albumin in die Vena femoralis als gunstigstes methodisches Vorgehen: Durch die Injektion des Tracers in die Vena femoralis wird der Bolus weniger auseinandergezogen als bei der sonst ublichen Injektionstechnik in die Vena cubiti, die Rezirkulation des Indikators ist geringer und die quantitativen Parameter weisen einen geringeren Variationskoeffizienten auf. Durch die Wahl von 99mTc-Human-Serum-Albumin wird die Abgrenzung der einzelnen Herzanteile erleichtert. Functional scintigrams of the heart were performed in 63 patients using different injection techniques and two radiopharmaceuticals (99mTc-pertechnitate and 99mTc-human serum albumen). A comparison of the results shows that injection of 99mTc-human serum albumen into the femoral vein gave the best results. Injection of the tracer into the femoral vein causes less dilution of the bolus than the usual injection technique into the cubital vein. There is less recirculation of the indicator resulting in lower co-efficients of variation of the quantitative parameters. The choice of 99mTc-human serum albumen facilitates demarcation of the individual cardiac chambers.

A method for quantitative detection of tricuspid regurgitation is proposed. In cases without tricuspid insufficiency or intracardiac shunt, 1/slope (ts-fv) of the earpiece dye-dilution curve after injection of dye into the femoreal vein (fv curve) was significantly correlated with that (ts-pa) of the curve after injection into the pulmonary artery (PA curve) within each range of right heart blood volume (rbv) calculated as a product of cardiac output and mean transit time difference between FV curve and PA curve. The relationship among the 3 parameters was expressed as a statistically significant regression equation; log (tsfv) equals 0.9858 log (ts-pa) plus 0.2980 log (RBV) minus 0.6418 (p small than 0.005, sd of predicted ts-fv equals plus or minus 0.591). The assumption was made that tricuspid regurgitation caused prolongation ot ts-fv without any changes in ts-pa or RBV, being based on the concepts of the indicator dispersion and of the path-length distribution. The ratio of tricuspid regurgitation to cardiac output was calculated from (observed ts-fv-predicted ts-fv)/predicted ts-fv, in which predicted ts-fv is the value calculated from ts-pa and RBV using the equation shown above. In 2 patients who manifested clinical tricuspid insufficiency, large amount of tricuspid regurgitant fraction was determined by this method. It is suggested that the present method utilizing double injections--single sampling dye-dilution technique is useful for clinical quantitation of tricuspid regurgitation.

The effect of a cadaver-derived vascular plasminogen activator (VA) on the degradation of fibrinogen, soluble fibrin monomer, and fibrin was studied and compared with the effect of equivalent fibrinolytic potencies of streptokinase (SK), urokinase (UK), and plasmin. The proteolytic activity of the three activators and plasmin was determined by a standard fibrin plate assay and was expressed in CTA units from a UK reference curve. Fibrinogen degradation was measured by clottable protein determinations and by an electrophoretic technique sensitive to small changes in the molecular weight of fibrinogen. When VA was incubated in plasma, no degradation of fibrinogen occurred, whereas rapid fibrinolysis took place after the plasma was clotted. By contrast, equivalent potencies of SK, UK, and plasmin caused extensive fibrinogenolysis. Since the plasmin added and that formed by the three activators had equivalent fibrinolytic activity, the failure of VA to induce fibrinogen degradation was attributed to antiactivators rather than antiplasmins. VA activity in plasma was consumed by clotting, whereas the antiactivator activity remained in the serum, suggesting dissociation of the VA-antiactivator complex on the fibrin clot. Fibrinogen and its soluble derivatives resisted degradation by VA in plasma because a solid phase appeared necessary for the complex to dissociate. The findings indicated that the degradation of fibrinogen or soluble fibrin in blood as a result of plasminogen activation by VA was unlikely to occur due to a large excess of antiactivator activity. Alternative pathways for their catabolism are discussed.

Cardiovascular changes caused by intraperitoneal insufflation with CO2 or N2O were measured in 15 mongrel dogs. Moderate progressive increases in intra-abdominal pressure (to 40 mm Hg) with either gas produced increases in mean arterial, right atrial, pleural, and femoral-vein pressures. Cardiac output and inferior vena caval flow were momentarily increased following the commencement of insufflation. However, both flows decreased precipitously as insufflation pressure was increased. At an intra-abdominal pressure of 40 mm Hg cardiac output and inferior vena caval flow were reduced more than 60 per cent in most cases. Peripheral resistance increased by approximately 200 per cent. Upon sudden release of abdominal pressure cardiac output and inferior vana caval flow increased but then returned to pre-insufflation values within seconds. Directly measured right atrial pressure increased with increasing insufflation pressure, but calculated transmural right atrial pressure decreased with the increase in intra-abdominal pressure. Insufflation with CO2 produced significant increases in PaCO2. However, cardiostimulatory effects due to elevated blood CO2 levels were not seen. The data from this study indicate that intraperitoneal insufflation produces serious hemodynamic alterations which are manifested by low cardiac output and elevated total peripheral resistance. In addition, directly measured right atrial pressure cannot be used clinically as an indicator of venous return to the heart since it reflects a composite of pleural and intra-abdominal insufflation pressure. (Key words: Anesthetics, gases, nitrous oxide; Carbon dioxide, intraperitoneal; Surgery, intraperitoneal insufflation; Heart, function, intraperitoneal insufflation.).

To determine the nature and extent of fetal metabolic changes during administration of inhalation anesthesia to the mother, the authors studied maternal and fetal cardiovascular and acid-base changes during general anesthesia with halothane and isoflurane in 16 near-term pregnant ewes with chronical

Microvascular repairs of 50 rabbits' femoral arteries averaging 0·9 mm in diameter gave an immediate patency rate of 100 per cent and a follow-up patency rate of 98 per cent after 3–41 days. The patency rate of 50 veins averaging 1·1 mm in diameter was 98 per cent immediately after surgery and 80 per cent after 3–41 days. No anticoagulants or antispasmodics were used. An additional 25 vein repairs with sufficient additional sutures to ensure more accurate apposition of the vein edges resulted in 100 per cent immediate patency and 92 per cent patency when examined during the 2nd week, the period which reveals the truest patency rate. Technical adequacy of the microvascular repair is the most important factor in ensuring final patency.

In an effort to understand O2, delivery to fetal tissues, we measured circulatory transit times using dye dilution methods in near-term fetuses of 19 ewes. Times from dye injection to peak response ( ± 1 sec) were: femoral vein to carotid artery 2.2, to femoral artery 2.6, to umbilical artery 3.7; jugular vein to carotid artery 1.7, to femoral artery 2.6; umbilical vein to carotid artery 1.9, to femoral artery 3.4, to umbilical artery 5.1, and umbilical artery to umbilical vein 5.4 sec. These rapid transits suggest that changes in placenta and peripheral tissues will quickly affect one another. The time for a complete circuit of blood through the fetus was 12.6 ( ± 1.0 SEM) sec. Following dye injections into an umbilical vein double peaks, separated by 4.9 sec, were recorded in peripheral arteries (44 observations), and the divergence localized to the ductus venosus. Based on relative areas under the two peaks, ductus flow averaged 0.425 ± 0.052 SEM of total flow returning from the placenta with the remainder taking a slow course through liver parenchyma.

Four dogs were infused with highly purified bovine parathyroid hormone until constant levels of immunoreactive hormone were attained in the circulation. Simultaneous samples of plasma were then obtained from the aorta, from hepatic, renal, and femoral veins, and later from a pulmonary artery and the left ventricle. Radioimmunoassay of these samples revealed mean arteriovenous differences of −23% across the liver and −19% across the kidney. No significant differences were found across the lung or lower extremity. After termination of the infusion the disappearance rate of immunoreactive hormone in external jugular-venous blood was multiexponential: the predominant initial T 1 2 was 4, 6, and 8 min, and the terminal component was 60, 54, and 99 min, respectively, in 3 dogs.

A technique is described for perfusion of the entire coronary arterial system of the dog heart in situ and for drainage of the coronary sinus blood. Both coronary arteries are cannulated without ligation of major ventricular branches and disconnected from the aorta. The cannulas are connected to an extracorporeal system allowing perfusion under controlled pressure, without ill effects to either the heart or the blood. The arterial perfusion system is fed from the femoral arteries of the dog. The coronary sinus is cannulated for draining the blood to a venous reservoir against a controlled pressure. From the reservoir the blood is pumped into a femoral vein. Thus a preparation is obtained in which the interdependency of coronary circulation and performance of the heart has been discontinued. Under careful monitoring of pressures and flows, and of blood temperature, blood gases and plasma electrolytes, the preparation has been kept in excellent condition for up to 7 hrs.

Organization and resolution were studied histologically in 48 valve pocket thrombi from femoral veins. The great majority were essentially single structures and the overlying cusps were normal and uninvolved, Thrombus adherence to the distal part of the vein wall in the pocket is followed by cellular and vascular invasion and progressive organization. At the same time many thrombi continue to grow by proximal addition, whilst others regress fully to fibrous intimal plaques. Central fibrinolytic changes are frequent. Focal organic fragmentation following endothelial cell surfacing is not uncommon and is a potential cause of thrombus detachment. Eight thrombi differed in that 5 were anchored to part of the cusp and 4 had a double structure resulting from two demarcated thrombotic events. One thrombus showed both features. In 3 thrombi with anchored cusps scarred intimal remnants of old thrombosis were present nearby. In 3 double structures recent thrombus had been laid down on organizing or organized thrombus, whilst the fourth was unique in that one part was composed solely of a large mass of platelets. The role of endothelium-induced fibrinolysis in preventing cusp adherence and of intact endothelium in preventing second thrombi are discussed.

Three medications clinically associated with thrombophlebitis when administered intravenously markedly reduced fibrinolytic activity in canine femoral vein. A fourth medication with no associated incidence of thrombophlebitis had no effect on fibrinolytic activity. Drug-induced decreases in vascular fibrinolytic activity may be significant in the etiology of postinfusion thrombophlebitis by allowing persistence and propagation of small fibrin thrombi.

The diameters of the ovarian, uterine, and femoral veins and the inferior vena cava were measured during stages of the estrous cycle in intact and hysterectomized mice and at intervals during pregnancy in mice with embryos in both uterine horns or in only the left horn. At metestrus I vein sizes were the least and were not significantly different in intact and hysterectomized mice. Ovarian and uterine veins showed the same or increased diameters at other stages of the cycle; veins enlarged progressively during pregnancy in intact mice. Non-gravid uterine horns showed little size increase as compared to gravid horns. Increases in vein diameter appeared to be correlated with local production of reproductive hormones. Evidence for transuterine migration of embryos was observed in 21 of 53 mice in which one uterine tube had been ligated or one ovary had been removed.Diameter measurements were taken in an investigation to determine the role of endogenous female sex hormones in effecting changes in the diameter of the ovarian, uterine and femoral veins and inferior vena cava during various stages of the estrous cycle in intact and hysterectomized mice and at intervals during pregnancy in mice with embryos in both uterine horns or in only the left horn. At metestrus 1 vein sizes were the least and were not significantly different in intact and hysterectomized mice. At other stages ovarian and uterine veins showed the same or increased diameters. Progressive venous enlargement during pregnancy occurred in intact mice. When compared to gravid horns, non-gravid uterine horns showed little size increase. Results of the study suggest that a correlation exists between localized activity of reproductive hormones and regulation of blood vessel size. The incidence of transuterine migration of embryos occurred in 21 of the 53 pregnant mice with unilateral tubal ligations or ovariectomies. In those 12 mice without embryos in the right uterine horn following right ovariectomy either failure of migration to occur or lack of sufficient local hormone permitted proper embryonic implantation and maintenance.

To demonstrate fat embolism during total hip replacement, thirty-four unselected patients were studied with an ultrasound probe over the femoral vein; twenty-one of them also had serial analyses of control and femoral venous blood for fat. Computer energy-density spectrum analysis of the sounds recorded by the ultrasound probe were performed; the fat emboli were counted in the blood samples by two histological techniques; and the plasma was analyzed for triglycerides before and after filtration. Characteristic sounds ("chirps") were heard with the Ultrasound probe during insertion of the femoral component in all patients. The individual chirps lasted two to five milliseconds and occurred every ten to fifteen milliseconds. The mean duration of activity was 4.2 minutes. Rarely, a few chirps were heard during seating of the acetabular component, reaming, or insertion of the cement into the femur. Blood samples during peak ultrasound activity showed: (1) seventy-nine globules per high-power field (control, 1.7) by the cryostat test; (2) 360 globules per high-power field (control, 6.8) by the millipore filter test; and (3) a mean drop in triglycerides after filtration of 27.8 milligrams per 100 milliliters (control, + 1.2). There was no clinical or laboratory evidence of the fat-embolism syndrome. Venting the femoral medullary canal during placement of the femoral component reduced the amount of fat emboli.

Indicator dilution experiments were done to determine the extraction of 85Sr during a single passage through capillaries of the tibial diaphysis. Extraction was estimated by injection of 85SrCl2 and a nonpermeant, reference tracer, T-1824-labeled albumin, into the nutrient artery and recording of the effluent venous dilution curves (femoral vein). The mean (+/- SD) maximal instantaneous extraction was 0.53 +/- 0.08 (N = 12). Net retention after 10 min, estimated from venous curves, was 0.41 +/- 0.06 (N = 12), which appeared not substantially different from the retention estimated by direct isotope counting of the tibias for 85Sr, 0.35 +/- 0.06 (N = 12). In a second set of experiments in intact animals, tibial 85Sr extraction after intravenous injection was apparently higher, 0.53 +/- 0.28 (N = 15). Values of tibial diaphyseal blood flow, estimated from washout curves for iodoantipyrine after tibial nutrient artery injection, were 1.47 +/- 0.63 ml/min per 100 g (N = 27). The extraction was not much diminished by higher flows. The estimates of permeability-surface area product (PS) for bone capillaries did increase with flow, suggesting recruitment of more capillaries at higher flows. PS values averaged 0.63 +/- 0.29 (N = 12); we conclude that the capillary membrane is a primary barrier to the passage of 85Sr and presumably other small hydrophilic solutes.

The mode of action of sulfonylureas as hypoglycemic agent is not clarified yet. But it has been said in general to act by increasing the secretion of insulin from the beta cells. While, some believe that their effect is independent on insulin secretion. In the previous report, it was demonstrated that the oral administration of single dose of tolbutamide failed to increase immunoreactive insulin (IRI) in the peripheral vein in spite of significant decrease of blood glucose and free fatty acid levels both in normal and diabetic subjects. In order to observe changes of IRI level in the pancreatic vein following the oral administration of single dose of tolbutamide, the present study was carried out to determine serum IRI level of the pancreatic and peripheral vein in dogs. Mongrel dogs of both sexes, weighing 7-12 kg were anesthetized with sodium pentobarbital. A catheter was inserted into the superior pancreatico-duodenal vein through its duodenal branch after a laparotomy. Another catheter was inserted into the femoral vein for the collection of peripheral venous blood. The experiment was started one hour after the operation. Blood glucose level decreased gradually to 39 per cent reduction of the previous level at 180 minutes after intragastric administration of single dose of tolbutamide (0.1 g per kg). Serum IRI level in the peripheral vein showed only slight increase, similar to the response in man. While, pancreatic vein IRI level increased gradually and showed a fourfold increment after 180 minutes (from 143 muU per ml to 556 muU per ml), associated with a constant elevation of plasma tolbutamide concentration which showed 6.4 mg per 100 ml after 180 minutes. Simultaneous administration of 0.1 g per kg of tolbutamide and the same dose of sodium bicarbonate caused 49 per cent reduction of blood glucose level and a doubling of the basal IRI level in the peripheral vein. Serum IRI level in the pancreatic vein rose sharply and demonstrated a peak at 90 minutes (620 per cent increase). The elevation of plasma tolbutamide concentration was somewhat more rapid than that after tolbutamide alone. From these observations, it was confirmed that an apparent secretion of insulin into the pancreatic vein was induced by the oral administration of tolbutamide alone, in spite of the lack of increase in the peripheral vein IRI. And it is emphasized that the changes of insulin level in the pancreatic vein should be taken into account in a study of insulin dynamics.

An electrode-stasis model which produces a deep vein thrombus in canine femoral vein is reported. The thrombus produced resembles a human thrombus on light microscopy. The fibrin crosslinkage in both thrombus and pulmonary embolus is similar to human fibrin crosslinked in vitro .

A number of reports in recent years have indicated that the administration of low dose intra-arterial reserpine has resulted in significant clinical improvement in patients with symptomatic vasospasm, with the benefits presumably resulting from regional vascular wall norepinephrine depletion with resultant vasodilatation. However, to date, there has been no evidence that such low dose reserpine actually alters vascular wall norepinephrine content. This study was performed to determine both regional and systemic effects of low dose intra-arterial reserpine on vascular-wall norepinephrine content, and the duration of any alterations. Twenty-four mongrel dogs had vascular segments excised and assayed for norepinephrine content, before and for up to 4 weeks following a single injection of reserpine, 0.01 mgm/kg, into one femoral artery. The results indicate a pronounced norepinephrine depletion in the injected femoral arterial system, with the reduction persisting for 2-4 weeks, at which time complete norepinephrine recovery occurred. The visceral vessels sampled also showed considerable norepinephrine depletion, indicating systemic spill-over of the drug from the injected peripheral arterial tree. The visceral vessels, however, showed maximal depletion at 24 hours, with recovery by 7 days.

The effect of ligation of veins on the longitudinal bone growth was studied in growing white rabbits. The daily longitudinal bone growth was determined with the tettacycline technique from the day before up to 40 days after operation. Ligation of the femoral vein, the circumflexal veins, and the deep femoral vein resulted in a temporary venous stasis. Additional ligation of the sciatic vein resulted in the same degree of venous stasis but a more longstanding effect. Neither of the operations resulted in growth stimulation or growth retardation compared with the control side. On the contrary, the ligation resulted in a minor temporary general growth retardation during the first days after the operation.

A 20-year-old female with congenital venous malformations in her left lower extremity had a self-limited, moderate consumption coagulopathy following angiographic studies. This episode was documented by both conventional coagulation studies and by 125l fibrinogen survival studies. It seems likely that venography triggered a local inflammation in the vascular malformations, which resulted in a localized consumption coagulopathy which abated as did the phlebitis in three weeks. We are aware of no prior reports of this complication of venography. Patients with venous malformations who undergo venography should have appropriate coagulation screening performed before and after the procedure so that any similar episode can be promptly diagnosed and treated, if treatment is deemed necessary.

The β-receptor blocking drugs, propranolol and alprenolol, and their dextrorotatory isomers were injected or infused into the vertebral artery of open-chest, anaesthetized cats and the hypotensive effects were compared to those obtained after injection or infusion of the same dose into a peripheral vein. Penetration of these drugs through the blood-brain barrier was studied by the assay of drug concentrations in plasma and cerebrospinal fluid. Propranolol probably lacks marked central hypotensive properties, whereas the blood pressure lowering effect of alprenolol was shown to possess a substantial central component.

Changes in the muscle tissue of the caudal vena cava of rats and its branches after disturbance of the blood drainage were studied by the methods of isotope biochemistry, autoradiography, immunomorphology, and cytophotometry. Enlargement and polyploidy of the DNA-synthesizing muscle cells with activation of protein synthesis in them and the formation of intimal layers resembling the muscular layers were found in the main trunk of the vein which was dilated the most. Activation of DNA and protein synthesis in the less distended femoral vein was much less marked than in the main trunk. Activation of protein synthesis occurred after a delay compared with the activation of DNA synthesis but both processes were phases of development of hypertrophy of the muscle tissue of the vessel wall in response to increased functional loading.

Surgical creation of a femoral arteriovenous fistula was used for treatment of anisomelia in twenty-eight patients. Seventeen patients required epiphyseodesis of the long extremity in addition to the fistula. Their discrepancies in length averaged 4.6 centimeters at fistula creation, 5.9 centimeters at epiphyseodesis, 3.6 centimeters at fistula closure, and 2.2 centimeters at maturity. Eleven patients were treated solely with surgical creation of an arteriovenous fistula. Their discrepancies averaged 4.1 centimeters at fistula creation, 2.4 centimeters at fistula closure, and 2.5 centimeters at maturity. The effect of the fistula was unpredictable and the complication rate was high.

1. Careful examination of the peripheral blood vessels is essential in choosing the site for an arteriovenous heterograft. 2. Ischemia of the hand or fingers was avoided by placing upper extremity grafts in the forearm. 3. In the lower extremity, if peripheral pulses are normal, a straight thigh graft is preferred. 4. The recipient vien in the antecubital fossa should be no less than 4 mm in diameter; in the lower extremity the venous anastomosis should be made to the common femoral vein. 5. "Graft hypertension" is a sign of inadequate venous runoff and should be corrected before false aneurysms develop or occlusion of the graft occurs. 6. Most thrombosed grafts can be reopened and should be explored promptly through an incision near the venous end.

A battery powered, portable cardiopulmonary bypass was used in 27 patients whose condition precluded movement to the operating room. Seventeen patients with massive pulmonary emboli and nine patients with extensive cardiopulmonary trauma, as well as one patient with massive drug overdose, were successfully placed on a cardiopulmonary bypass at their bedsides, within 15 minutes of cardiac arrest, using femoral artery and femoral vein cannulation. Twelve of the patients with massive pulmonary emboli were saved. In six of the eight patients who required portable cardiopulmonary bypass for massive, traumatic thoracic injuries, hemorrhage was controlled and repair done to allow discontinuance of bypass.

In experiments with graded exercise of 15 men (6 untrained, 3 semitrained, 6 endurance-trained) the trained subjects showed a massive shift to the right of the in vivo O2 dissociation curve (ODC) of femoral venous blood. At a saturation of 20 to 25% (18 mkp/sec) Po2 was about 9 mm Hg higher for the trained than for the untrained group. The following factors play a role: 1. The 2,3-diphosphoglycerate [2,3-DPG] concentration was increased by 15 to 20% in the trained group which explains about 2 mm Hg of the diffenence in Po2-2. Exercise acidosis in the femoral venous blood depends to a large extent on CO2 in the trained, but on lactic acid in the untrained group. At low saturations the CO2-Bohr effect increases sharply thus having a greater importance in the trained subjects. This factor can explain about 2 mm Hg of the difference. However, influence of chloride and 2,3-DPG on the Bohr effect must be taken into consideration. 3. Since the large ODC-shift to the right of the trained group was not reproducible under in vitro conditions, it is suggested that a rapidly decaying unknown substance accounts for the remaining difference in Po2.

Effects of lidocaine on blood pressure, heart rate, electrocortical activity, pH, and blood gases were studied in chronically catheterized sheep fetuses in utero. Lidocaine infused at a constant rate of less than I mg. · min. −1 · Kg. −1 into a fetal femoral vein did not cause changes in fetal blood pressure, heart rate, pH, or blood gases. Infusion rates above 1 mg. · min. −1 · Kg. −1 caused sudden, phasic increases in blood pressure in the majority of the fetuses. The heart rate increased in association with each phasic increase in blood pressure. In some fetuses the heart rate decelerated after the initial acceleration. Fetal electrocortical recordings showed that each phasic change in blood pressure and heart rate was secondary to epileptiform activity. The concentration of lidocaine in fetal arterial blood was 11.6 ± 3.8 μg per milliliter when the first phasic increase in blood pressure occurred. Tracheal pressure recordings showed deep fetal breathing movements with each epileptiform activity. It is concluded that lidocaine causes convulsions in the fetal sheep and that the cardiovascular changes are due to central stimulation during these convulsions. In newborn lambs lidocaine produced similar epileptiform activity associated with tonic-clonic convulsions and cardiovascular changes. Fetal arterial pH was not affected until the phasic changes occurred, after which the pH fell rapidly in the majority of the fetuses. In three paralyzed fetuses the pH also decreased at the onset of phasic increases in blood pressure. This indicated that muscular activtiy was not the main cause of the acidemia during fetal epileptiform activity. Bolus injections of lidocaine in doses of 3.0 to 22.2 mg. per kilogram of fetal weight caused an immediate decrease in blood pressure and heart rate. These changes were related to the dose of lidocaine. The convulsive dose of lidocaine as a bolus injection ranged from 8.0 to 22.2 mg. per kilogram.