The use of an external bypass during experimental total hepatectomy

An external bypass has been developed which is designed to prevent acute portacaval hypertension during the performance of a recently described method of hepatectomy. The temporary external shunt has considerably prolonged the safe period of portacaval occlusion, and extended the use of this method of hepatectomy to personnel relatively untrained in surgery. © 1960

The treatment of penetrating wounds of the inferior vena cava

During the last 5 years, 10 gunshot and 2 stab wounds of the inferior vena cava have been treated, with 11 survivals and 1 death. The lacerations were above the renal veins in 4 cases and below in the others. All patients had other serious visceral injuries. Treatment consisted of suture repair in 11 cases and ligation in the twelfth. Upon exploration, free intraperitoneal bleeding from the caval wound had ceased in every case. The signal finding was a retroperitoneal hematoma which was often deceptively small. Commonly, the surgeon explored the retroperitoneal space in order to treat other visceral injuries, only to be confronted with unexpected massive hemorrhage when the hematoma was entered. Difficulties in controlling the bleeding are often related to the well-developed collateral system by which different segments of the inferior vena cava are freely connected. When a hematoma is found in the vicinity of the great vessels and the retroperitoneal space is to be explored, certain precautions should be observed. These include provision for adequate exposure, procurement of blood, and adjustment of lighting. Additional help can be summoned and vascular instruments should be brought to the operating table. A large-bore needle or cut-down should be placed in an arm vein. The posterior peritoneal incision should be planned for maximum and rapid exposure, so that hemorrhage can be quickly controlled when the plane of the hematoma is entered. © 1962

Studies on the rejection of the transplanted homologous dog liver.

Dogs in which livers have been replaced with hepatic homografts usually die in 5 to 10 days. Liver metabolism is not detectably abnormal at first, but gradual deterioration of function commences on the fourth or fifth day. There was histologic evidence of rejection in all dogs dying after 4 days. This ranged from minimal mononuclear infiltration to almost complete destruction of parenchyma. In the longest survivor, 20 1/2 days, histologic changes were less profound than in many animals dying earlier. Widespread histologic changes were found in host reticuloendothelial system, involving the bone marrow, kidneys, lungs, lymph nodes, and other tissues. These consisted of fixed tissue proliferation and infiltration of mononuclear cells, principally plasma cells. These changes were thought to be due to a general host reticuloendothelial response to the antigenic stimulus of the homograft

The treatment of penetrating wounds of the inferior vena cava

During the last 5 years, 10 gunshot and 2 stab wounds of the inferior vena cava have been treated, with 11 survivals and 1 death. The lacerations were above the renal veins in 4 cases and below in the others. All patients had other serious visceral injuries. Treatment consisted of suture repair in 11 cases and ligation in the twelfth. Upon exploration, free intraperitoneal bleeding from the caval wound had ceased in every case. The signal finding was a retroperitoneal hematoma which was often deceptively small. Commonly, the surgeon explored the retroperitoneal space in order to treat other visceral injuries, only to be confronted with unexpected massive hemorrhage when the hematoma was entered. Difficulties in controlling the bleeding are often related to the well-developed collateral system by which different segments of the inferior vena cava are freely connected. When a hematoma is found in the vicinity of the great vessels and the retroperitoneal space is to be explored, certain precautions should be observed. These include provision for adequate exposure, procurement of blood, and adjustment of lighting. Additional help can be summoned and vascular instruments should be brought to the operating table. A large-bore needle or cut-down should be placed in an arm vein. The posterior peritoneal incision should be planned for maximum and rapid exposure, so that hemorrhage can be quickly controlled when the plane of the hematoma is entered. © 1962

The role of cerebral edema in ischemic cerebral neuropathy after cardiac arrest in dogs and monkeys and its treatment with hypertonic urea

1. 1. The value of hypertonic urea in forestalling the neurologic sequellae after cardiac arrest has been assessed in dogs and monkeys. Simulated cardiac arrest was produced with an inflow-outflow occlusion technique in which the blood supply to the heart was maintained during the period of complete cerebral ischemia. 2. 2. A number of factors increase the duration of cardiac arrest which can be tolerated without gross neurologic sequellae. These include the presence of an effective circulatory state before and after the arrest, the administration of 100 per cent oxygen before and after the test period, the use of an efficient respirator, and avoidance of premature efforts to promote spontaneous respirations postoperatively. 3. 3. Under optimum conditions almost all dogs and monkeys will recover completely after 12 minutes of simulated cardiac arrest. With longer occlusions, death and serious neurologic morbidity occur. 4. 4. Monkeys and dogs were subjected to simulated cardiac arrest for 14 minutes. Hypertonic urea did not materially decrease either the mortality rate or neurologic morbidity in either species, as compared to the recovery rate in controls, despite the fact that the urea-treated animals had demonstrably less brain swelling. 5. 5. From this it is concluded that cerebral edema is an overemphasized factor in the post-cardiac arrest syndrome, and that the principal deterrent to recovery is anoxic injury to the neurons which is not beneficially influenced by reduction of brain volume. © 1960

Reconstructive problems in canine liver homotransplantation with special reference to the postoperative role of hepatic venous flow

The homologous canine liver has been transplanted to recipient animals in which total hepatectomy and splenectomy have been performed. The longest survival after placement of the liver homograft was 20 1/2 days. Protection from hepatic ischemia for as long as 2 hours was obtained by cooling the donor liver to 10 to 20 degrees C. The arterial supply was restored through a hepatic artery-aortic pedicle which was removed in continuity with the liver and anastomosed to the descending aorta of the recipient. Internal biliary drainage was established. The volume of venous flow transmitted to the transplanted liver has been shown to be an important determinant of success. When this was excessive, as when both the portal and inferior caval flows were directed through the liver, hepatic and splanchnic beds. When the portal flow was normal or reduced, outflow block rarely occurred. An attempt has been made to relate the development of outflow block as it occurred in the transplanted liver to other circumstances, including hemorrhagic shock, in which similar phenomena have been observed

Light-evoked Somatosensory Perception of Transgenic Rats That Express Channelrhodopsin-2 in Dorsal Root Ganglion Cells

In vertebrate somatosensory systems, each mode of touch-pressure, temperature or pain is sensed by sensory endings of different dorsal root ganglion (DRG) neurons, which conducted to the specific cortical loci as nerve impulses. Therefore, direct electrical stimulation of the peripheral nerve endings causes an erroneous sensation to be conducted by the nerve. We have recently generated several transgenic lines of rat in which channelrhodopsin-2 (ChR2) transgene is driven by the Thy-1.2 promoter. In one of them, W-TChR2V4, some neurons were endowed with photosensitivity by the introduction of the ChR2 gene, coding an algal photoreceptor molecule. The DRG neurons expressing ChR2 were immunohistochemically identified using specific antibodies to the markers of mechanoreceptive or nociceptive neurons. Their peripheral nerve endings in the plantar skin as well as the central endings in the spinal cord were also examined. We identified that ChR2 is expressed in a certain population of large neurons in the DRG of W-TChR2V4. On the basis of their morphology and molecular markers, these neurons were classified as mechanoreceptive but not nociceptive. ChR2 was also distributed in their peripheral sensory nerve endings, some of which were closely associated with CK20-positive cells to form Merkel cell-neurite complexes or with S-100-positive cells to form structures like Meissner's corpuscles. These nerve endings are thus suggested to be involved in the sensing of touch. Each W-TChR2V4 rat showed a sensory-evoked behavior in response to blue LED flashes on the plantar skin. It is thus suggested that each rat acquired an unusual sensory modality of sensing blue light through the skin as touch-pressure. This light-evoked somatosensory perception should facilitate study of how the complex tactile sense emerges in the brain

The Na(+)/Ca(2+) exchanger NCKX4 governs termination and adaptation of the mammalian olfactory response

Sensory perception requires accurate encoding of stimulus information by sensory receptor cells. We identified NCKX4, a potassium-dependent Na(+)/Ca(2+) exchanger, as being necessary for rapid response termination and proper adaptation of vertebrate olfactory sensory neurons (OSNs). Nckx4(-/-) (also known as Slc24a4) mouse OSNs displayed substantially prolonged responses and stronger adaptation. Single-cell electrophysiological analyses revealed that the majority of Na(+)-dependent Ca(2+) exchange in OSNs relevant to sensory transduction is a result of NCKX4 and that Nckx4(-/-) mouse OSNs are deficient in encoding action potentials on repeated stimulation. Olfactory-specific Nckx4(-/-) mice had lower body weights and a reduced ability to locate an odorous source. These results establish the role of NCKX4 in shaping olfactory responses and suggest that rapid response termination and proper adaptation of peripheral sensory receptor cells tune the sensory system for optimal perception