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The navigation challenges posed by Deep Space 1's flyby of comet Borrelly were considerable due to the uncertainty in the knowledge of the comet's ephemeris, as well as difficulty in determining the spacecraft's ephemeris caused by relatively large non-gravitational forces acting on the comet. The challenges were met by using a combination of radio, optical, and interferometric data types to obtain a final fly by accuracy of less than 10 km.

A description of the scientific objectives and the hardware development of the Water-Mist Fire Suppression experiment (Mist) for the STS-107 mission of the Space Shuttle and for the International Space Station is presented. The overall objective of Mist is to study the feasibility of developing fine-water-mist systems as the next generation of fire suppressants that may replace the currently used halon-based systems, which are powerful ozone-depleting agents in the stratosphere. The experiments planned for STS-107 will be conducted on the Combustion Module (CM-2) and will explore the influence of water mists on premixed flames propagating in a cylindrical tube under microgravity conditions and will evaluate the role of thermal, physical, and chemical mechanisms in the water-mist/flame interaction. The effects of droplet size and water concentration on the laminar flame speed and flame shape will be used as the measure of fire suppression efficacy. A numerical simulation of this interaction has been developed and reduced-gravity ground experiments have been conducted to obtain the preliminary data necessary to define the scientific objectives and technical issues of the spacecraft experiments. The lessons learned during the design, fabrication, testing, and integration of Mist into CM-2 are presented along with the future objectives of the Mist insert in the Combustion Integrated Rack (CIR) onboard the International Space Station (ISS).

Methods for automation of nucleic acid selections are being developed. The selection of aptamers has been successfully automated using a Biomek 2000 workstation. Several binding species with nanomolar affinities were isolated from diverse populations. Automation of a deoxyribozyme ligase selection is in progress. The process requires eleven times more robotic manipulations than an aptamer selection. The random sequence pool contained a 5' iodine residue and the ligation substrate contained a 3' phosphorothioate. Initially, a manual deoxyribozyme ligase selection was performed. Thirteen rounds of selection yielded ligators with a 400-fold increase in activity over the initial pool. Several difficulties were encountered during the automation of DNA catalyst selection, including effectively washing bead-bound DNA, pipetting 50% glycerol solutions, purifying single strand DNA, and monitoring the progress of the selection as it is performed. Nonetheless, automated selection experiments for deoxyribozyme ligases were carried out starting from either a naive pool or round eight of the manually selected pool. In both instances, the first round of selection revealed an increase in ligase activity. However, this activity was lost in subsequent rounds. A possible cause could be mispriming during the unmonitored PCR reactions. Potential solutions include pool redesign, fewer PCR cycles, and integration of a fluorescence microtiter plate reader to allow robotic 'observation' of the selections as they progress.

Chromosome locations of two allele-specific SCAR (sequence characterized amplified region) DNA markers in wheat (Triticum aestivum L.) were found by identifying critical aneuploids obtained by the pollination of haploids. One SCAR, linked to a gene for antibiotic resistance to wheat midge (Sitodiplosis mosellana Gehin) was on chromosome 2B. The second SCAR, linked to one of three genes for white seed color was on 3B. Unemasculated haploids of M11 (resistant & white seeded) were pollinated with BW252 (susceptible & A three-gene red) yielding about 1 hybrid seed per 4 heads pollinated. Out of 94 seeds tested, endosperm DNA of 15 seeds lacked one SCAR or the other, signaling a critical deficiency. These 15 selected seeds gave 9 viable hybrids of which 2 were false negatives. By screening for polymorphic microsatellites, informative markers were obtained for all chromosomes except 7D. Chromosomes missing from marker negative hybrids were inferred from monomorphism of chromosome-specific microsatellites plus meiotic data. Hybrids lacking the midge SCAR lacked 2B from M11 while hybrids lacking the white SCAR lacked all or part of 3B from M11. While some of the aneuploids were complex, simple monosomics were recovered for both 2B and 3B.

Field tomatoes were sprayed with chlorothalonil on a fixed–interval spray program and a TOM–CAST spray program with disease severity value threshold of 18. Foliage samples from upper and lower canopy layers were collected prior to spray re–applications. Chlorothalonil residue data were compared to the chlorothalonil efficacy threshold (1.2 g/cm 2 ). Using a seven–day interval program, eight of the nine and seven of the nine spray intervals had chlorothalonil residues above the critical level for the upper and lower canopy layers, respectively. Using the TOM–CAST program, four of the five spray intervals had chlorothalonil residues above the critical level for both upper and lower canopy layers when the DSV threshold of 18 was reached. Persistence of chlorothalonil residues at effective concentrations could lengthen the spray interval beyond the DSV–based spray recommendation.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier induces bone for reconstruction of skeletal defects. The rhBMP-2/ACS implant is prepared by administering a rhBMP-2 solution to dry ACS. Once prepared, rhBMP-2/ACS forms a moldable, cohesive, and adhesive implant. However, rhBMP-2/ACS does not have sufficient structural strength to withstand soft tissue compression at specific anatomic sites. To more fully understand the mechanisms that affect bone induction by rhBMP-2/ACS in the presence of soft tissue compression, it would be useful to have a preclinical model that appropriately simulates such circumstances in patients. This pilot study evaluated one such potential model.Bilateral, Class III alveolar defects were surgically produced in 4 adult mongrel dogs following extraction of the mandibular fourth premolars and reduction of the alveolar ridge. After an 8-week healing interval, mucoperiosteal flaps were elevated and rhBMP-2/ACS or rhBMP-2/ACS combined with hydroxyapatite (HA) was implanted into contralateral defects. The animals were euthanized at 12 weeks post-augmentation and block biopsies processed for histologic evaluation.Limited augmentation followed implantation of rhBMP-2/ACS (0.7 +/- 0.6 mm). In contrast, sites receiving rhBMP-2/ACS/HA exhibited clinically relevant ridge augmentation (5.5 +/- 1.6 mm). Defects implanted with rhBMP-2/ACS exhibited dense trabeculation within the corpus of the reduced alveolar process. The cortices appeared intact without evidence of expansion into the defect area. Three defects receiving rhBMP-2/ACS/HA exhibited sparse bone trabeculae amidst HA particles, fibrovascular tissue, and marrow. Commonly, the HA particles were encapsulated by fibrous tissue. Some particles were observed in contact with bone.The results suggests that rhBMP-2/ACS has limited effect alone in this augmentation model of Class III alveolar ridge defects. Inclusion of HA into the rhBMP-2 construct results in clinically relevant augmentation, however, the quality of bone is compromised.

Successful treatment of renal anemia with recombinant erythropoietin (rhEPO) raises the question of whether the renal anemia symptom complex requires complete correction. Current arguments against increasing hemoglobin (Hb) levels above 10-11 g/dl are impaired hemodynamics, increased risk of vascular access occlusion, unmanageable hypertension and dialysis complications. The aim of the study was to determine whether sustained Hb normalization using long-term rhEPO causes hemorheological changes with a potentially negative hemodynamic impact. The study was conducted in 42 rhEPO-treated dialysis patients with stable Hb11.0 g/dl for at least 20 weeks. The mean Hb of the total study group was 12.8 1.1 g/dl. To study the effect of Hb as a risk indicator in greater detail, the patients were divided into two groups, with hematocrits above and below 0.40. Hemorheology (erythrocyte deformability and aggregation, plasma viscosity) showed no significant changes, including vs a healthy control group. Throughout the period of increased rhEPO administration, no increase was observed in the incidence of hypertension or vascular thrombosis.the marked additional quality-of-life benefit achieved by complete correction of renal anemia harbors no substantial increase in treatment risk.

The target-hematocrit (Hct) for the correction of renal anemia by recombinant human erythropoeitin (rhEPO) therapy is discussed controversially. A normalization of the Hct that could lead to a further improvement of the patients status, is often rejected, because of possible side effects as a result of an increase in blood viscosity. Hemodialysis (HD) induces an acute hemoconcentration due to ultrafiltration that might influence these risk factors negatively and therefore conflict with the normalization of Hct. The aim of this study was to investigate the changes in rheological and biochemical parameters in chronic HD patients with a normal initial Hct before hemodialysis. Results in 39 patients are given as mean +/- SD before/after HD: Hct 0.42 +/- 0.05/0.45 +/- 0.05 (p0.001), hemoglobin (g/dI) 13.3 +/- 1.0/14.4 +/- 1.3 (p0.001), MCV (fl) 99.3 +/- 5.7/99.1 +/- 5.5, MCHC (mM/l) 19.9 +/- 0.6/20.1 +/- 0.6 (p0.01), red blood cell (RBC) elongation (%) 60.97 +/- 3.67/60.99 +/- 3.73, RBC aggregation index AI0 0.52 +/- 0.12/0.50 +/- 0.12, AI4 0.52 +/- 0.14/0.51 +/- 0.12, plasma viscosity 1.74 +/- 0.14/1.92 +/- 0.20 (p0.001), whole blood viscosity (WBV), etaabs.100(mPas) 5.91 +/- 0.78/6.80 +/- 1.2 (p0.001), etaabs.0.01(mPas) 75.81 +/- 35.48/167.656 +/- 98.686 (p0.05), ultrafiltration (FM) 2.1 +/- 1.1. The biochemical parameters protein, albumin, IgG, IgA, IgM, cholesterol, transferrin and fibrinogen are significantly increased after HD. The hemoconcentration during HD is associated with a significant increase in WBV, mainly associated with the increase in Hct (r = 0.83), but not exceeding the normal range compared to healthy controls. The increase in plasma viscosity is correlated mainly with an increase in protein (r = 0.80), albumin (r = 0.74), and fibrinogen (r = 0.54). No significant changes in RBC aggregation and deformability were observed during the HD session. In conclusion, from the rheological point of view it is unlikely that the normalization of the Hct will contribute to an increased risk in access thrombosis or thromboembolic events in HD patients.

Amino acid and alpha-keto acid metabolism depends on oxygen availability in chronic hemodialysis patients. Malnutrition in hemodialysis (HD) patients with renal anemia is reflected in an abnormal plasma amino acid profile. We wished to determine the extent to which malnutrition can be improved by correcting anemia with recombinant human erythropoietin (rhEPO) and supplemental iron. As specific parameters we measured and compared the plasma concentrations of the branched-chain amino acids valine, leucine and isoleucine and their transamination products - major participants in proteolysis and protein biosynthesis - using HPLC with fluorescence detection in 45 severely anemic HD patients (group A: Hb 7.2 +/- 0.8 g/dl), 34 patients with partially corrected anemia (group B: Hb 10.3 +/- 0.6 g/dl) and 35 HD patients with totally corrected anemia (group C: Hb 13.5 +/- 0.7 g/dl). Sixty healthy subjects (group N: Hb 14.2 +/- 1.1 g/dl) served as controls. Correlating with the degree of correction (A/B/C/N), a significant shift to anabolic metabolism was observed in the plasma levels of valine: 130/146/155/205 micromol/l; leucine: 73/71/80/110 micromol/l and alpha-ketoisocaproate (KIC): 11.4/11.8/15.1/ 30.4 micromol/l. It is concluded that energy metabolism becomes increasingly anabolic as hemoglobin levels are normalized.

Today's commodity disk drives, the basic unit of storage for computer systems large and small, are actually small computers, with a processor, memory and a network connection, in addition to the spinning magnetic material that stores the data. Large collections of data are becoming larger, and people are beginning to analyze, rather than simply store-and-forget, these masses of data. At the same time, advances in I/O performance have lagged the rapid development of commodity processor and memory technology. This paper describes the use of Active Disks to take advantage of the processing power on individual disk drives to run a carefully chosen portion of a relational database system. Moving a portion of the database processing to execute directly at the disk drives improves performance by: 1) dramatically reducing data traffic; and 2) exploiting the parallelism in large storage systems. It provides a new point of leverage to overcome the I/O bottleneck. This paper discusses how to map all the basic database operations - select, project, and join - onto an Active Disk system. The changes required are small and the performance gains are dramatic. A prototype based on the Postgres database system demonstrates a factor of 2x performance improvement on a small system using a portion of the TPC-D decision support benchmark, with the promise of larger improvements in more realistically-sized systems.

Freeblock scheduling is a new approach to utilizing more of a disk's potential media bandwidth. By filling rotational latency periods with useful media transfers, 20-50% of a never-idle disk's bandwidth can often be provided to background applications with no effect on foreground response times. This paper describes freeblock scheduling and demonstrates its value with simulation studies of two concrete applications: segment cleaning and data mining. Free segment cleaning often allows an LFS file system to maintain its ideal write performance when cleaning overheads would otherwise reduce performance by up to a factor of three. Free data mining can achieve over 47 full disk scans per day on an active transaction processing system, with no effect on its disk performance.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is an osteoinductive protein that plays a pivotal role in bone growth and regeneration. Studies conducted in many mammalian species and, most recently, human clinical studies, have provided definitive evidence of the ability of rhBMP-2 to induce bone. The findings of these studies provide a rationale for investigating whether rhBMP-2 therapy will be clinically useful in orthopedic practice. Consequently, we have initiated a clinical research program to evaluate the safety and efficacy of rhBMP-2 therapy in open tibial fractures. A prospective observational study (involving no rhBMP-2 treatment) was conducted to define an appropriate patient population for rhBMP-2 clinical trials and has provided critical information related to the design and execution of future studies. The rhBMP-2 clinical trials include a small pilot feasibility study and several larger studies. Data from the pilot feasibility study have demonstrated that implantation of rhBMP-2 (combined with an absorbable collagen sponge) is surgically feasible and safe. Larger, multicenter clinical studies are now ongoing in the United States and abroad.

The associations between self-reported rewards and difficulties of caregiving and burden were examined in a sample of 200 informal caregivers to older post-rehabilitation patients. Sixteen percent (16%) of caregivers reported that caregiving was physically difficult only, 15% reported emotional difficulties only, 11% reported social difficulties only, 17% reported multiple difficulties, and 40% had no difficulties. Each type of difficulty (e.g., social, emotional, and physical) was significantly associated with burden in univariate and multiple linear regression analyses, controlling for confounding characteristics. Caregivers reporting multiple types of difficulty experienced higher levels of burden than caregivers who reported only one type of difficulty. Caregivers who received more rewards from caregiving reported fewer difficulties. Caregiving rewards had no independent effect on burden but modified the associations between social and emotional difficulties and burden. In summary, caregiving rewards and difficulties were not mutually exclusive, and their relationship in turn affected burden.

Monoclonal antibody (mAb) A33 detects a glycoprotein homogeneously expressed by > 95% of human colon cancers and by normal colon cells. The A33 antigen is not secreted or shed and after mAb A33 binds to antigen on the cell membrane, a fraction of membrane-bound mAb A33 is internalized into endosomes. Phase I 131I-mAb A33 biodistribution studies have shown consistent, specific tumor-targeting, and phase I radioimmunotherapy trials with 131I- or 125I-mAb A33 have demonstrated antitumor effects. Here we describe a nude mouse model that was established using a human colon cancer cell line, SW1222, which grows as a relatively hypovascular, invasive heterotransplant when injected i.m. Peak uptake of 131I-labeled or 111In-chelated mAb A33 was observed at 48-96 h, with a mean of 34% (SE +/- 5.0) and 46.7% (SE +/- 1.7) injected dose per gram of tumor tissue, respectively. 111In-mAb A33 was retained in tumor tissue longer than halide radioimmunoconjugates. The specificity of antibody localization was assessed using a control antibody (tumor uptake and pharmacokinetics), a control tumor, corrections for vascular antibody blood-pooling in tumor tissue, and blocking of radiolabeled mAb A33 localization by pretreating mice with excess unlabeled mAb A33. These experiments demonstrate that mAb A33 localization in tumor was specific, and they emphasize the unexpected rapidity with which the antibody localizes. Our conclusions were confirmed by immunohistochemical techniques which allowed direct visualization of localization and distribution of the humanized version of mAb A33 in tumor tissue. Furthermore, antibody doses approximating tumor-saturating doses demonstrated that a homogeneous distribution of antibody in tumor is possible. This model will be valuable for studies focusing on general physiologic aspects of antibody-to-tumor cell localization and critical as a guide to the evaluation of various A33 antibody constructs and combinations with other therapies for the treatment of colon cancer.

Low density liporoteins (LDL) are internalised by the LDL receptor, which is expressed on the surface of eucaryotic cells. Metabolisation and chemical modification of LDLs lead to a shift in receptor affinity: modified LDLs are internalised through scavenger receptors, which are expressed on cells of the monocyte/macrophage lineage. Coupling of substances with pharmacological activity, such as azidothymidine, to LDL results in a cell specific uptake of these drugs into macrophages by the scavenger receptor. Thus, drug–LDL derivatives might work as tools for macrophage specific drug targeting. In this context, it is essential to know the drug binding capacity, the optimal derivatization conditions, and the amount of drug molecules covalently bound to the LDL particle. In this study, we compared methods for optimal derivatisation and estimation of coupling efficiency, such as semiquantitative lipoprotein gel electrophoresis, ultraviolet (UV) spectrophotometry, radiometric quantification, and specific protein hydrolysis.

The automation of interplanetary spacecraft is becoming increasingly desirable to meet various mission requirements. A prototype autonomous spacecraft which will flyby an asteroid and comet is slated for flight in mid-1998 as part of NASA's New Millennium Program. This spacecraft will navigate by using optical data taken by the onboard camera to determine its orbit, and use this information to predict its future trajectory and make necessary course corrections. The basic navigation data available from the camera are star-relative astrometric observations of solar system bodies which can be used to determine line-of-sight vectors to those objects. The directional sightings are obtained by determining the precise centers of the object and stars in the image. During interplanetary cruise, centerfinding is performed by using two pattern matching techniques inherited from the Galileo mission. Near-encounter images are processed with a separate algorithm employing image modeling and brightness centroiding. This paper describes the image processing algorithms, and the results of a ground-based test of the algorithms using real data.

The in-vitro amino acid (AA) and alpha-keto acid (KA) metabolism of bioreactors initially seeded with 2.5 x 10(9) pig hepatocytes was investigated with a perfusion technique. Considerable changes in the culture medium concentrations of AA and KA were measured during the first days in culture. This is indicative of dynamic cellular metabolism in the initial phase. While the concentration of pyruvate decreased starting on the first day, alpha-ketoglutarate, alpha-ketoisocaproate, alpha-ketoisovalerate, and alpha-keto-beta-methyl-n-valerate were synthesized. The long term use of hepatocyte cultures in bioreactors and thus a desirable clinical hybrid liver support therapy appears to be possible since the hepatocytes switched, after 15 days in culture, to steady-state conditions with a stable amino acid turnover featuring general AA uptake accompanied by KA release. The release of branched chain KA, in particular that of alpha-ketoisocaproate, reflects an effective transamination activity in the bioreactor system. Primary pig hepatocytes cultivated in hybrid liver support systems for therapy of acute liver failure or as devices for bridging to liver transplantation can sustain amino acid metabolism for at least 30 days in vitro. However, an initial disorder following the cell isolation that is demonstrated may limit immediate utilization of the systems prior to the reorganisation of the cells to tissue-like structures in bioreactors.

In hemodialysis patients, free amino acids and alpha-ketoacids in plasma were determined by fluorescence HPLC to assess the effect of alpha-ketoglutarate administration in combination with the phosphate binder calcium carbonate on the amino acid metabolism. During 1 year of therapy in parallel to inorganic phosphate, urea in plasma decreased significantly, histidine, arginine and proline as well as branched chain alpha-ketoacids, in particular alpha-ketoisocaproate, a regulator of protein metabolism, increased. Thus, administration of alpha-ketoglutarate with calcium carbonate effectively improves amino acid metabolism in hemodialysis patients as it decreases hyperphosphatemia.

Calcium alpha-ketoglutarate administration to 24 malnourished hemodialysis patients for 1 year leads to a significant increase in plasma concentrations of L-arginine from 53.6 +/- 18.3 (compared to a healthy control group: 87.5 +/- 27.3) to 71.1 +/- 15.9 mumol/l (p0.05). Furthermore, concentrations in plasma of proline and histidine, precursors of glutamate biosynthesis, are increased; inorganic phosphate and urea are significantly decreased in hemodialysis patients after 1 year of calcium alpha-ketoglutarate administration.

Macrophages activated by macrophage-colony stimulating factor (M-CSF) are potent immune effector cells and can mediate both in vitro cytotoxicity and antitumor effects in vivo. A Phase I trial combining M-CSF with R24, a mouse monoclonal antibody against GD3 ganglioside that has been shown to localize to melanoma tumors, induce inflammation at tumor sites, and result in major tumor responses in some patients with melanoma was performed.Nineteen patients with metastatic melanoma received a 14-day continuous intravenous infusion of 80 micrograms/kg/day of recombinant human M-CSF. R24 was administered daily by intravenous infusion on days 6-10 at doses of 1, 3, 10, 30, and 50 micrograms/m2/day.All patients developed pruritus and urticaria; 13 patients developed transient thrombocytopenia less than 100,000/mm3. The maximum tolerated dose was not reached. All patients developed a monocytosis characterized by increased expression of the antigen HLA-DR and decreased expression of CD14, a phenotype reported to represent a subpopulation of monocytes active in mediating antibody-directed cellular cytotoxicity. Other biologic effects of treatment included marked but transient decreases in total cholesterol, low density lipoprotein, and high density lipoprotein. Three patients experienced tumor regression in breast, liver, and lymph node metastases and received a second course of therapy. Six of the 19 patients, one of whom received no further therapy, survived more than 2 years and 4 of these patients remain alive 24 to 37 months after treatment. Of the six patients with liver metastases, three (50%) survived more than 2.5 years and one remains alive at 37+ months.Combination therapy with R24 and M-CSF resulted in both clinical and biologic effects that warrant further investigation of this combination.

Macrophages, besides helper T-lymphocytes, are target cells for the human immunodeficiency virus (HIV). We report on a mechanism to deliver selectively antiretroviral drugs to cells of the monocyte/macrophage lineage. These cells and cells of the endothelium express scavenger receptors which mediate the transport of modified low density lipoprotein (LDL). LDL modified by covalently bound azidothymidine (AZT), a potent inhibitor of HIV replication, is internalized via this pathway into human macrophages. Treatment of HIV-1 infected human macrophages with AZT-LDL showed in vitro efficient inhibition of viral replication. In contrast, HIV replication in T-lymphocytes (Molt 4/8), which do not express scavenger receptors, is not inhibited by AZT-LDL but by free AZT.

The amino acid patterns of medium perfusate in a liver cell bioreactor developed for a hybrid liver support system have been measured. There were considerable changes in the concentrations of glutamic acid, glutamine, alanine, arginine, ornithine and branched chain amino acids during the first 10 days which is indicative of dynamic cellular metabolism. From day 15, steady state conditions of nitrogen metabolism are reflected by stable amino acid turnover. Monitoring of urea, K+, and P-450 activity suggests that hepatocytes have switched to a stable protein synthesis with a general amino acid uptake and keto acid release following cell volume increase.

Isolated pig liver cells cultured using a perfusion technique were analyzed over 39 days to test their ability to change the perfusate alpha-keto acid profile. While the pyruvate concentration in the culture medium decreased as of the first day, the alpha-ketoglutarate (KG), alpha-ketoisocaproate (KIC), alpha-ketoisovalerate (KIV) and alpha-keto-beta-methyl-n-valerate (KMV) were synthesized immediately and released by the liver cells. The metabolic capacity of the cell culture system increased up to day 10, decreased during the following 5 days and reached a steady state beyond day 15, which was maintained for at least 30 days. The branched chain alpha-keto acid release, in particular alpha-ketoisocaproate, reflects an effective transamination capacity of the newly developed culture system and shows an intact protein biosynthesis for at least 30 days in vitro.

Covalent coupling of thymidine and azidothymidine (ZIDOVUDINE) to epsilon-amino groups of lysine side chains of LDL-Apo B is described. This procedure generates LDL-nucleoside particles that exhibits affinity solely for the scavenger receptor pathway on macrophages which is demonstrated by cell culture experiments. Autoradiography shows that 3H-thymidine, as representative of nucleosides, is delivered to the cell nucleus. Hence internalization, lysosomal cleavage and triphosphorylation of thymidine evidently had occurred. The application of this new method of drug targeting is macrophage selective inhibition of HIV-reverse transcriptase in AIDS.

We report a flexible strategy for the high level expression of a recombinant human monoclonal antibody (mAb) in Chinese hamster ovary (CHO) cells, initially using COS monkey kidney cell transfections to evaluate rapidly modifications to immunoglobulin (Ig) DNA constructs. Using sequential transfections with two amplifiable markers, we generated CHO cell lines and clones that secrete 80-110 micrograms/10(6) cells/24 hours of a mouse-human chimeric IgG1 kappa mAb. This cellular productivity is considerably greater than most murine hybridomas and transfected myelomas. Our data also demonstrate that genomic kappa sequences can improve mAb expression in COS and CHO cells. As a paradigm, we focused our expression studies on a human chimeric form of 3F8, a murine mAb that binds to ganglioside GD2 on neuroblastoma and melanoma tumor cells.

The optical navigation process as practiced during the Gaspra encounter is presented. The characteristics of image formation for a single-frame mosaic picture required the development of a new image processing algorithm to extract the optical measurements. A detailed formulation of this algorithm is presented along with the results of applying it to the pictures returned from the spacecraft.

Summary: Therapy of renal anaemia in haemodialysis patients with chronic renal failure by application of recombinant human erythropoietin leads to an increase of the haematocrit. Rejuvenation of the erythrocyte population results in a decrease of the median density (D50), an increase of cell age-dependent enzyme activities, such as aspartate aminotransferase, and elevated concentrations of purine nucleotides in the erythrocytes. After density gradient separation of erythrocyte populations into cell age-dependent fractions, the concentrations of adenosine-S'- triphosphate, guanosine-5'-triphosphate and guanosine-5'-diphosphate were be found to be elevated by 25 —100% in all cell fractions from haemodialysis patients, compared with a healthy control group. Therapy of haemodialysis patients with recombinant human erythropoietin leads to further increase (65%) of ATP in the younger (low density) cells, but not in the older (high density) cells. The elevated concentrations of ATP and total adenine nucleotides during recombinant human erythropoietin therapy possibly result in improved deformability of erythrocytes. The data point to an enhancement of the proportion of younger erythrocytes, but not to an improvement of the reduced life span of erythrocytes of haemodialysis patients during therapy with recombinant human erythropoietin.

We have tried to present a picture of what is conceptually involved in our studies thus far. The major finding has been the observation that two widely different types of transient absorption spectra are to be seen in nature, the type we call “impact spectra”, and the type we term “statistical spectra”. Both types, when interpreted and analyzed properly, can provide information about difference potentials.

Antiviral therapy of human immunodeficiency virus (HIV) infection is currently based on inhibition of reverse transcriptase by dideoxynucleosides, such as azidothymidine. Because of widespread toxicity it is reasonable to selectively target these drugs to infected cells. This may be accomplished utilizing drug-LDL conjugates, which are internalized via cell specific receptor pathways. With respect to HIV infection, scavenger receptors of the macrophage system seems to offer a hopeful perspective. This pathway requires chemical modification of surface polarity of the LDL. Cell experiments were conducted in HepG2 hepatocytes, which express apolipoprotein B receptors, and in P388 macrophages, which express scavenger receptors. LDL particles to be conjugated were isolated from blood donor plasma and from LDL-apheresis waste material. Non-covalent LDL conjugation with amphiphilic nucleoside derivatives produced only an unspecific nucleoside transfer to cell membranes, due to instability of the LDL conjugates. An experimental method (coincubation test) was developed to identify those conjugates that are stable in the presence of other lipophilic compartments. Covalent coupling of nucleosides to the apolipoprotein B moiety of LDL particles resulted in stable conjugates. As a consequence, the surface charge became negative, and the LDL displayed scavenger receptor affinity rather than apolipoprotein B receptor affinity. Selective targeting of nucleosides to macrophages can be accomplished by covalent coupling to LDL.

Employee absenteeism is an important economic variable that needs to be examined by occupational health nurses when evaluating worksite health promotion programs. Two of the three Blue Cross and Blue Shield Plan studies suggested that their programs acted to contain absenteeism among program participants. The worksite programs that met with success tended to be comprehensive and to have strong management support. Strengths of the three studies included the use of comparison groups and pretest measures of absenteeism in the analyses. Limitations included selection bias, subject dropout over time, limited monitoring of the program process, and the use of an analysis method that did not consider the statistical characteristics of the absenteeism variable.

In August 1989 the Voyager 2 spacecraft encountered Neptune and Triton. Precise knowledge of the trajectory of the spacecraft relative to the Neptunian system was essential to ensure successful observations during the flyby, and to perform trajectory control. Determination of the orbit of Voyager 2 with respect to the Neptunian system was accomplished by the use of radiometric Doppler, range, and VLBI observations of the spacecraft in combination with spacecraft-based optical observations of Neptune, Triton, Nereid, and the Voyager-discovered satellite 1989N1. These data types were used in a new version of the JPL Orbit Determination Program to determine the orbit of the spacecraft as well as Neptunian system ephemerides and dynamical parameters, resulting in accurate delivery of the spacecraft to targeted conditions at Neptune and Triton.

Optical navigation techniques were required to successfully complete the planetary exploration phase of the NASA deep-space Voyager mission. The last of Voyager's planetary encounters, with Neptune, posed unique problems from an optical navigation standpoint. In this paper we briefly review general aspects of the optical navigation process as practiced during the Voyager mission, and discuss in detail particular features of the Neptune encounter which affected optical navigation. New approaches to the centerfinding problem were developed for both stars and extended bodies, and these are described. Results of the optical navigation data analysis are presented, as well as a description of the optical orbit determination system and results of its use during encounter. Partially as a result of the optical navigation processing, results of scientific significance were obtained. These results include the discovery and orbit determination of several new satellites of Neptune and the determination of the size of Triton, Neptune's largest moon.

Renal anemia is caused in part by a reduced life span of red blood cells (RBCs) and by reduced erythropoietin biosynthesis in the damaged kidney. The RBC age can be determined by density gradient centrifugation and estimation of cell-age-dependent enzyme activities, as aspartate aminotransferase. The RBC age distribution influences the median density (D50) of RBCs and the blood rheology in coherence with the hematocrit. In our study, the median density was determined by Percoll density gradient centrifugation in 18 healthy subjects (D50 = 1.0674 +/- 0.0016 g/ml) and in 14 hemodialysis patients (D50 = 1.0674 +/- 0.0016 g/ml in the course of recombinant human erythropoietin (rhEPO) therapy. During the first 4 weeks of therapy, a strong rejuvenation of RBCs was observed whereby the D50 reached a minimum after 2 weeks (D50 = 1.0655 +/- 0.0022 g/ml; p less than 0.05 vs. value before therapy) and a steady state after 4 weeks (D50 = 1.0658 +/- 0.0013 g/ml; p less than 0.1 vs. value before therapy). In 5 of the patients with elevated plasma parathyroid hormone (i-PTH) concentrations greater than 10 pmol/l, a significantly (p less than 0.05) reduced amount of younger RBCs (D50 = 1.0675 +/- 0.0016 g/ml) was observed in the first 2 weeks of rhEPO therapy as compared to patients with i-PTH less than 10 pmol/l (D50 = 1.0677 +/- 0.0019 g/ml). Thus, erythropoiesis in the early phase of rhEPO therapy is strongly influenced by elevated plasma i-PTH concentrations. Therefore, a gradual increase in rhEPO doses is preferable before therapy at elevated doses with an uncontrolled increase in RBC amount.

Renal anemia is the result of reduced erythropoietin (EPO) biosynthesis in the diseased kidney and also in part the result of a reduced life span of red blood cells (RBCs). An increase in density and a decrease in enzyme equipment (aspartate aminotransferase; GOT) of RBCs reflect cell age. In the following study, the density distribution (median density D50; determined by Percoll density gradients) and GOT activities of RBCs were measured in patients on acetate (HDA; n = 15) and bicarbonate (HDB; n = 51) hemodialysis. Hemoglobin (Hb) concentrations were: in the HDB group, 9.1 +/- 3.4 g/dl; in the HDA group, 6.2 +/- 1.2 g/dl, and, in a control (C) group of healthy persons, 14.0 +/- 1.5 g/dl. 14 HDB patients with severe anemia received EPO therapy during 1 year. D50 were found as follows: group C, 1.0674 +/- 0.0016 g/ml; HDB, 1.0674 +/- 0.0015 g/ml, and HDA, 1.0660 +/- 0.0012 g/ml (HDA vs. group C: p less than 0.05; HDA vs. HDB: p less than 0.05. D50 were elevated in the subgroups of HDA and HDB patients with severe anemia (Hb less than 8 g/dl). During activated erythropoiesis by EPO therapy, D50 decreased from 1.06739 +/- 0.0015 to 1.0656 +/- 0.0014 g/ml. The GOT activities in RBCs demonstrated a rejuvenation of the RBC population in the HDB group (6.4 +/- 2.5 U/g Hb) and HDA group (5.9 +/- 3.1 U/g Hb) compared to group C (3.9 +/- 1.3 U/g Hb).(ABSTRACT TRUNCATED AT 250 WORDS)

3568 Background: Although CRT has emerged as the preferred treatment for T3 and/or lymph node (LN) positive rectal cancer, Sauer et al (NEJM 2004) demonstrated that 18% of patients deemed suitable for preop CRT via endorectal ultrasound (ERUS) were overstaged and therefore received unnecessary preoperative CRT. Since data also suggest that LN negative rectal cancer s/p TME may not need adjuvant therapy, it is reasonable to consider the omission of radiotherapy for the cT3N0 subset. We therefore determined the accuracy of pre-CRT ERUS/MRI staging in order to explore the validity of a non-radiation approach for cT3N0 disease. Methods: 188 ERUS/MRI staged T3N0 rectal cancer patients from 6 insitutions in the US, Europe and Asia received preoperative CRT (5-FU based and 45–52.5 Gy) followed by radical resection. Rates of pathologic complete response (pCR) and mesorectal LN involvement were determined. Results: Tumors were located a median of 5 centimeters from the anal verge. Sphincter-preserving surgery was performed in 135 (81%) patients. Overall pCR was 19%. Median number of LN sampled was 9 (range 0–38). Rate of positive LN was significantly associated with T-stage: pT0: 3%, pT1: 7%, pT2: 20%, pT3–4: 36%(p=0.001). 41 patients (22%) had pathologically positive mesorectal LN. There was no significant difference in rate of positive LN between those staged by ERUS and MRI(25% vs 16%, p=0.19). Conclusions: Accuracy of preoperative ERUS/MRI for identifying mid to distal T3N0 rectal cancer is limited, as 22% will have undetected mesorectal LN involvement despite CRT. Therefore, ERUS/MRI staged T3N0 patients should continue to receive preoperative CRT. Although 19% are overstaged and therefore overtreated, our data suggest that an even larger number would be understaged and require postoperative CRT, which is associated with inferior local control, higher toxicity, and poor functional outcome. No significant financial relationships to disclose.

Polycrystalline samples of spinel compounds FeCr 2− x In x S 4 have been obtained in the range 0 ≦ x ≦ 2. The nonlinear changes of the cell parameters are explained by the nonlinear behavior of the inversion parameter λ according to the ionic distribution Fe 2+ 1−λ In 3+ λ [Cr 3+ 2− x Fe 2+ λ In 3+ x −λ ]S 2− 4 . Room temperature 57 Fe-Mo¨ssbauer spectra exhibit two sets of absorptions for tetrahedrally and octahedrally coordinated Fe, respectively, each consisting of several overlapping doublets of similar isomer shifts but varying quadrupole splittings. The partial intensity of octahedral-site Fe is in agreement with λ. The spectra can be understood by accounting for the influence of variable octahedral-site neighbors on tetrahedral-site iron.

Polycristalline samples of the system Fe1+xYb2−xS4 have been investigated in the range 0,0 ≤ x ≤ 0,4 in both the low temperature structure and the spinel-type high temperature structure. The lattice constants of the spinels decrease linearly with increasing x; the tetrahedral sites are occupied by iron only. The valence distribution Fe+2 Fe+3xYb+32−x S−24 and a slight distortion of the spinel lattice are concluded from the Mosbauer parameters at room temperature.