Radionuclides in pinon pine (Pinus edulis) nuts from Los Alamos National Laboratory lands and the dose from consumption.

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food--the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of 3H, 137Cs, 90Sr, totU, 238Pu, 239,240Pu, and 241Am in soils (0- to 12-in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of 3H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN fromLANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 microSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 microSv). Soil-to-nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.

Limb preservation for reimplantation. a review.

Although reimplantation of severed limbs and other parts of the body has become prevalent in recent years, the questions of how best to preserve limbs for reimplantation and how to determine if a transected part is viable have not been fully answered. The problem of preservation involves combating direct anoxic damage to tissue as well as combating the changes in the vascular system that lead to the "no reflow phenomenon." Current information concerning kidney preservation as well as experimental and clinical reports on limb preservation are reviewed in this article, and suggestions are made for further investigations.

"Nautral" canine model of infantile hydrocephalus.

A review of the current knowledge about a variety of aspects of infantile hydrocephalus suggests that one cause of this problem is subarachnoid blood from birth trauma interacting with an anatomically immature cerebrospinal fluid-absorbing system. To test this hypothesis and to create a model that could be used to devise various methods of prophylaxis and therapy, we injected autologous blood into the cisterna magna of puppies, followed the size of their ventricles with serial computerized tomographic (CT) scans, and evaluated the scanning electron microscopic (SEM) appearance of the ventricular walls and subarachnoid space. By injecting blood until the dogs were just at the point of apnea, we obtained a 46% incidence of hydrocephalus with a 13% mortality rate. The amount of blood accepted was variable. The size of the ventricles was followed with CT scans; the time course of hydrocephalus was variable, and in some cases it resolved. SEM revealed significant regional, free cell aggregation and calcification, especially over the base of the brain, which was most marked in the animals that developed hydrocephalus. This suggests a more marked reaction or a lesser ability to clear the subarachnoid blood in those animals, although the reason for this is not clear. Possible uses for this model are suggested.

Embolus radiolabelling in a new canine model.

Embolus radiolabelling with 131I fibrinogen was studied in a canine model of internal carotid artery embolization. The dog was chosen as the experimental animal because of its maxillocarotid artery which permits collateral flow round the occlusion and helps to prevent strokes. Clot was prepared by incubating blood at room temperature to inactivate plasminogen activators and then refrigerating it to promote clot retraction. Emboli persisting 48 hours were seen in 80% of animals. Major strokes were not seen when 0.25 to 0.30 cm3 were used. Autoradiography and well counting revealed uptake of isotope. The test, when refined, should provide a tool for the investigation of thromboemboli.

Some adjuncts for the microvascular laboratory.

A new mouthprop for airway maintenance in the anesthetized rat, a vessel stabilizer and dilator, and a modification of the technique for end-to-end anastomosis in deep wounds are described.

Kidney donation: needs and possibilities.

The need for cadaver kidney donors far surpasses the present supply. The subject of how to increase the number of donors is extremely complex, involving not only the medical issue of determination of brain death, but also philosophical, religious, legal, political, psychological, and economic considerations and the opinions of leaders and lay groups. It now seems that the physician can rapidly and unequivocally ascertain brain death, that the law not only recognizes this but can facilitate organ retrieval, that adequate numbers of potential donors should be available, and that both the public and physicians generally favor retrieval. Our survey of patients seeking aid in the emergency room revealed that 19% had signed the donor statement on their driving license. Of the neurosurgeons and neurologists who responded to a questionnaire, 74% had requested donation and 37% had obtained permission for organ retrieval. Review of our case material revealed that 60% of individuals with head injuries alone who were hospitalized for over 3 days were suitable donors. Of the 54 kidneys retrieved during a 6-month period, 49 (90%) were transplanted. Because most potential donors come to the attention of neurosurgeons and neurologists and because it seems ethically appropriate for physicians to consider transplantation when death is certain, we suggest that an organized effort be undertaken to develop a liaison with transplantation services to facilitate the process of obtaining adequate numbers of cadaver kidneys.

A new canine model of proximal internal carotid embolism.

A new model of internal carotid artery embolism was developed using autologous clot. The clot was prepared by incubating blood at room temperature for 2 hours to inactivate plasminogen activators and then refrigerating it at 4 degrees C for 22 hours. The purpose of the experiment was to devise a model of the intravascular lesion and not of stroke itself. The dog was chosen as the experimental animal since it has a maxillocarotid artery which permits collateral flow beyond proximal internal carotid artery occlusions. A volume of clot measuring 0.25 to 0.30 cc was sufficient to occlude the artery for 48 hours in 80% of the animals without causing major strokes. We have used this model to study clot radiolabeling and suggest it may also have application for evaluating thrombolytic drugs.