A report from the UNOS Scientific Renal Transplant Registry

The UNOS Kidney Transplant Registry is now fully operational. Aside from scientific reports from UCLA, analysis of the same data base from investigators who initiate projects through UNOS central in Richmond, as well as from HICFA and USRDS, can be anticipated. Plans are underway to simplify the reporting process. With the large number of accumulated cases, it should be possible to analyze many factors in the future. Presently, histocompatibility differences in living related vs cadaver donors and degrees of HLA mismatching among recipients of cadaveric kidneys are major factors. Immunization by transplant rejection is the second most important factor.

Uptake of glutamate and cysteine in C-6 glioma cells and in cultured astrocytes

The uptake of glutamate in rat glioma C-6 cells and cultured astrocytes derived from rat cerebral hemispheres was found to be mediated by a Na(+)-dependent and a Na(+)-independent system. The Na(+)-dependent system was inhibited by aspartate and was consistent with the commonly occurring system designated system X-AG. The Na(+)-independent system was inhibited by cystine and was consistent with system x-c described in various types of cells in the periphery. It was also found that quisqualate selectively and competitively interfered with the Na(+)-independent glutamate uptake. In C-6 cells, the glutamate uptake via systems X-AG and x-c accounted for approximately 35% and 55% of the total uptake, respectively, at 0.05 mM glutamate. In cultured astrocytes, the glutamate uptake via system X-AG was very potent, whereas the uptake via system xc- was relatively weak and its contribution to the total uptake of glutamate seemed almost negligible. However, in both C-6 cells and astrocytes, system xc- was necessary for the uptake of cystine, another substrate of system xc-. Cystine in the culture medium was an essential precursor of glutathione, and the inhibition of the cystine uptake by excess glutamate as a competitor led to a severe deficiency in glutathione, followed by cell degeneration.

Endothelial attachment and plasmalemmal apposition in the transcellular movement of intravascular leukemic cells entering the myeloid parenchyma

The plasmalemmal relationship between metastases-forming leukemia cells and myeloid sinus endothelium during the transmural passage of the leukemia cells has been studied in rat bone marrow. After the myeloid vascular system was freed from normal circulating blood cells, the bone marrow was perfused with a suspension of leukemia cells derived from an ascites tumor. The bone marrow was then fixed by perfusion with double aldehyde with and without the addition of tannic acid. Leukemia cells were seen adhering to the adluminal aspect of the sinus endothelium and in all stages of endothelial penetration. The penetration of the sinus wall was independent of endothelial junctions; i.e., the transmural passage into the myeloid parenchyma was transcellular. At these sites, there were restricted areas of close plasmalemmal appositions of the two cell types where the intraplasmalemmal space was reduced to 2.3 nm. This space was interrupted by electron densities of 5 nm diameter and spaced 9 nm center to center. These close plasmalemmal appositions extended over distances ranging from 150 nm to 200 nm. It is suggested on the basis of the structural similarity that these heptalaminar complexes of close plasmalemmal apposition represent the structural equivalent of gap junctions and may be sites of intercellular communication requisite for transmural passage. When tannic acid was added to the fixative, there were extended areas of apparent fusion of the plasmalemmas of the two cell types, at the sites both of adhesion and of endothelial penetration. This fusion was limited to the outer leaflets of the two plasmalemmas, resulting in a single pentalaminar complex. These pentalaminar complexes extended over decidedly longer distances than the presumed gap junctions seen in the nontannic-acid-fixed material. The tannic acid material did not show the heptalaminar gap junction type of plasmalemmal apposition. It is believed likely that the tannic-acid-induced pentalaminar complexes may incorporate the smaller heptalaminar ones. The factors underlying the plasmalemmal configurational differences between the tannic acid and non-tannic-acid material remain undetermined.

Kinetic analysis of new formation, internalization, and turnover of bristle coated pits of the myeloid sinuses

The rate of new formation of bristle coated pits (BCP) of the myeloid sinuses, their internalization, and turnover was determined by labeling of BCP with bovine albumin adsorbed to colloidal gold (Au) at low temperatures (0 degrees C to 4 degrees C), followed by endothelial activation with balanced saline at 38 degrees C to 40 degrees C for graded periods of time. New formation of BCP was practically instantaneous, occurring within 28 seconds, a time span which includes the in situ assembly of the coating protein clathrin as well as of the material effecting the binding of the ligand. Almost the entire population of BCP was turned over in 6 minutes, a time period which encompasses the initial formation of the plasmalemmal bristle coated binding site to the internalization of BCP. The number of BCP varied within a narrow range indicating a substantial degree of physiological constancy resulting from a quantitative parallelism between internalization and new formation of bristle coated binding sites. The number of BCP is markedly reduced in the prolonged (greater than 12 minutes) absence of endocytosable material. The reduction in the number of BCP is reversible. The binding to BCP at low temperatures (0 degrees C to 4 degrees C) of a series of proteinaceous substances adsorbed to Au was examined for the following Au complexes: bovine albumin/Au, rat albumin/Au, IgG/Au, orosomucoid/Au, ovalbumin/Au, fetuin/Au, transferrin/Au, insulin/Au, low density lipoprotein/Au, alpha 2 macroglobulin/Au, and Au stabilized by polyethylene glycol. All these Au complexes bound to BCP although there were differences in the degree of affinity as judged by the number of BCP labeled and by the number of Au/complex particles present in the labeled BCP. Au stabilized by polyethylene glycol did not bind to BCP. Under the condition of these experiments, bovine albumin/Au had the highest degree of affinity for BCP and was therefore selected for the kinetic studies.

Internal structure of the postcapillary high-endothelial venules of rodent lymph nodes and Peyer's patches and the transendothelial lymphocyte passage

Scanning electron microscopy (SEM) shows that the postcapillary high-endothelial venules of lymph nodes and Peyer's patches consist of two segments each with a different surface relief: a proximal segment with a cobblestone surface pattern and a distal segment of interlacing cytoplasmic plates. Both segments have deep adluminal crevices in which lymphocytes are lodged. The internal structural configuration of this endothelium has been examined by transmission electron microscopy (TEM) of serial sections of lymph nodes and Peyer's patches of mice, rats, and guinea pigs. The serial sections revealed that the endothelial cell bodies and their cytoplasmic extensions were disposed in a direction generally lateral to the luminal surface and intruded into the intercellular spaces of similarly disposed neighboring endothelial cells, resulting in a complex interlacing cellular pattern. Lymphocytes penetrated the endothelial cell body and secondarily followed an intracellular pathway through which they entered the extravascular compartment. At the exposed surfaces of the adluminal venule wall, recirculating lymphocytes were seen in SEM images to enter the endothelium by penetrating the endothelial cell body. The mode of migration of lymphocytes lodged in the endothelial crevices could be determined by SEM and has been examined by TEM of serial sections. At these locations as at the exposed surfaces, lymphocytes also entered the venule by penetrating the endothelial cell body. At both sites this transcellular pathway was followed by lymphocyte entry into the intercellular spaces from which they migrated into the extravascular compartment.

In vivo exocytosis of lysosomes by the endothelium of the venous sinuses of bone marrow and liver: visualization at normal and low body temperature

We have visualized the exocytosis of lysosomes into the peripheral circulation by the phagocytic endothelia of the venous sinuses of liver and bone marrow of rats. Perfusion fixation at normal body temperature produced images of the earliest stages of lysosomal exocytosis. After fixation at low body temperatures (7-12 degrees C), advanced stages of this process became evident, showing extrusion of lysosomes and their contents into the circulation. It is postulated that this form of exocytosis has escaped structural detection because of its rapidity and relative infrequency as compared to merocrine secretory exocytosis, and that fixation at low body temperatures arrests or slows down these exocytic events in sufficient measure for ultrastructural visualization. The possibility that this lysosomal exocytosis contributes to the presence of lysosomal enzymes detected in the peripheral blood should be considered. In addition, it is likely that lysosomal degradation products may be discharged by exocytosis into the circulation.

Acid-labile interferon produced in human peripheral leukocytes by induction with Sendai virus

An acid-labile interferon-alpha (IFN-alpha) exists in IFN produced in human peripheral leukocytes with Sendai virus. This activity was found in fractions of molecular weights about 100 000 (100K), 58K and 44K. The IFN activity in the 100K fraction was neutralized with anti-HuIFN-alpha serum alone, but activity in the 58K and 44K fractions was neutralized only by a mixture of anti-HuIFN-alpha and anti-HuIFN-beta sera.

A computer based decision-making model for poultry inspection

In an attempt to develop a predictive model for poultry inspection at processing plants, a systems research design was developed to examine poultry population health dynamics from hatching to processing. Five cooperating Alabama poultry firms with 5 to 7 growers from each firm were identified to form the study unit. The farms were stratified to represent good, average, and poor producers. Via epidemiologic causal diagrams, variables with potential influence on poultry condemnation due to diseases were identified for hatchery, broiler, and processing subsystems. Field and/or laboratory data were generated for each study unit and for each variable. Using stepwise multiple regression and discriminant analysis, a predictor model with a multiple correlation coefficient (R) of 0.91 and multiple coefficient of determination (R2) of 0.82 was developed. A discriminant analysis model for classifying a flock into high or low condemnation group, using 0.1% to 2.0% as the demarcation line, was also developed. This latter model had overall correct classification probabilities ranging from 0.88 to 1.0. The 2 decision-making models were then computerized, using Beginner's All-purpose Symbolic Instruction Code (BASIC). On the day of processing, the grower provides the inspector with selected information, which is entered on a computer. Alternatives for scaled-down inspection or others are then systematically evaluated by the computer, and decision-making information is provided to the user.

In vivo endocytosis by bristle coated pits of protein tracers and their intracellular transport in the endothelial cells lining the sinuses of the liver. I. The endosomal disposition

The present observations describe the endocystosis and intracellular transport in the endothelial cells lining the sinuses of the rat liver and occurring 3 min after intravenous administration of two protein tracers: horseradish peroxidase and ferritin. Internalization of the proteins is exclusively by bristle coated pits followed by intracellular sequestration in bristle coated vesicles (diameter 90-210 nm). No other form of endocytosis is present in the endothelial cells of the liver sinuses. The bristle coated vesicles fuse with smooth membrane lined tubules (diameter 20-70 nm) termed transfer tubules. In this way the tracers are deposited into the lumens of the transfer tubules. The transfer tubules in turn fuse with preexisting electron-lucent endosomes which then receive the protein markers. In addition, direct fusion of bristle coated vesicles with endosomes occurs in limited measure. Bristle coated vesicles may fuse with other bristle coated vesicles while losing their clathrin coat, resulting in the formation of new endosomes which may enlarge through fusion with additional bristle coated vesicles or perhaps also with transfer tubules. The sinus endothelium also contains lysosomal vesicles which appear as dense bodies or multivesicular bodies. No protein tracers have been observed in these dense bodies at the time interval (i.e., 3 min) examined. Neither has a direct fusion between endosomes and lysosomes been found. The transfer tubules may be continuous with or may be derived from cisternae of the Golgi complex. No luminal continuity between transfer tubules and endoplasmic reticulum has been observed. The sinus endothelium also contains small bristle coated vesicles (30-40 nm) often attached to Golgi cisternae. These do not participate in the transport of endocytosed protein tracer and are in this respect functionally distinct from the large bristle coated vesicles derived from the endothelial plasmalemma. Serial sections show that there are extensive connections between the endocytic transport organelles: bristle coated vesicles, transfer tubules, and endosomes, possibly forming an intracellular luminal continuum.

In vivo endocytosis by bristle coated pits of protein tracers and their intracellular transport in the endothelial cells lining the sinuses of the liver. II. The endosomal-lysosomal transformation

The events leading to lysosomal activity in the sinus endothelium of the rat liver have been studied by means of intravascularly injected ferritin at time intervals ranging from 0.5 min to 1 hr after administration. From 6 min on, the dense body-type lysosomes contain ferritin. There are direct luminal communications of transfer tubules with these lysosomes. In time, there is a marked progressive increase in the number of ferritin-containing dense body-type lysosomes. No formation of lysosomes de novo nor a direct fusion of endosomes with lysosomes has been observed. Endosomes, however, continue to be formed as endocytosis continues. These observations are interpreted as indicating a transport of hydrolytic enzymes by the transfer tubules to the newly formed ferritin containing endosomes, which in this way are transformed into ferritin containing lysosomes. The ferritin-containing lysosomes increase considerably in size by fusing with each other. Continued endocytosis of ferritin leads to an increase of ferritin density in the dense bodies. This increase in particle density cannot be explained solely on the basis of transport by luminal fusion of the endocytic organelles, but requires an active transport mechanism. Administration of low doses of ferritin shows that the bristle coated pits of the sinus endothelium have a high degree of in vivo affinity for protein and that this endothelium must be considered to be an avid catabolic endocytic system.

Noninvasive flowmetry in vascular surgery: use of a noninvasive electromagnetic flowmeter

Using an in vitro model, the measurements made using a noninvasive electromagnetic flowmeter have been validated using standard square wave electromagnetic flowmetry. Clinically, the noninvasive electromagnetic flowmeter provides information as to the functional significance of vascular occlusive disease that is not available through other techniques, gives an accurate, quantitative measurement of the peak pulsatile blood flow through a limb, thus providing an index of tissue perfusion and therefore, the degree of involvement of the disease in the peripheral vascular system.

The structure of the sinus wall of the lymph node relative to its endocytic properties and transmural cell passage

The internal structure of cells lining the lymphatic sinus of the lymph node includes the presence of large bristle-coated vesicles, transfer tubules, and vesicular organelles for the uptake and intracellular disposition of endocytosed material. The lining cells of the sinuses phagocytose particulate material from the lymph in the same manner as the sinusoidal endothelium of the bone marrow takes up particulates from the blood and, thus, are similar in this respect to the endothelial lining of the bone marrow sinusoids. Transmission and scanning electron microscopic examination of the lymphatic sinus wall in rat lymph nodes show that the walls of the lymphatic sinuses are continuous and do not have permanent apertures allowing free communication between the extrasinusoidal and intrasinusoidal compartments in the lymph node. Migrating lymphocytes cross the lymphatic sinus wall intracellularly, i.e., through the body of the lining cell, by making a temporary migration pore, which closes after the cell has reached the lumen of the sinus. In addition there are sporadic aggregations of macrophages in transmural positions. The direction of their movement is unknown.