Glucose uptake of the spinal cord in patients with multiple sclerosis detected by ¹8F-fluorodeoxyglucose PET/CT after walking.

STUDY DESIGN: Case report. OBJECTIVES: To determine [(18)F]-fluorodeoxyglucose ([(18)F]-FDG) uptake in the spinal cord of patients with multiple sclerosis (MS) was compared with healthy controls after treadmill walking. SETTING: Colorado Translational Research Imaging Center, University of Colorado School of Medicine, Aurora, CO, USA. METHODS: Eight mildly disabled patients with MS and eight healthy subjects performed 15 min of treadmill walking at a self-selected pace. Two minutes after walking began, each participant was injected with ≈8 mCi of [(18)F]-FDG into a catheter inserted into an antecubital vein. Immediately after walking positron emission tomography/computed tomography (PET/CT) imaging was performed on each participant. Images were analyzed to determine [(18)F]-FDG uptake within the spinal cord. RESULTS: Total spinal cord [(18)F]-FDG uptake was lower in patients with MS (1.48±0.36 and 1.55±0.33, P=0.04), specifically within the thoracic (1.32±0.27 and 1.41±0.24, P<0.01) and the lumbar (1.58±0.40 and 1.89±0.43, P=0.04) spinal cord regions. CONCLUSION: This is the first report of [(18)F]-FDG uptake in the spinal cord of patients with MS. The decreased [(18)F]-FDG uptake within the thoracic and lumbar spinal cord regions could be associated with autonomic nervous system and walking/motor dysfunctions that are often seen in patients with MS. PET/CT imaging with [(18)F]-FDG is highly useful for the demonstration of impaired glucose metabolism in the spinal cord of patients with MS.

Specificity of antibodies: primary structural basis of hapten binding.

The primiary structure of the 83 residues of the NH(2)-terminus of the V(II), region was determined for each of three different antibodies to hapten which were produced in inbred guinea pigs. Each antibody had a different and distinctive primary structure within each of the two "hypervariable" regions (Hv1 and Hv2) included in the analyzed part of the variable region of the heavy chain. The sequences of Hvl and Hv2 in the three antibodies were either unique or of restricted variability compared with those of "normnal" immunoglobulin G2. Further implication of Hv1 and Hv2 in contributing to ligand-binding specificity of antibodies came from the placement of residues modified by affinity labeling reagents in these hypervariable regions.

Characterization of growth-inhibitory activities associated with an alpha-macroglobulin of mice.

An alpha-macroglobulin (AMG) of similar size and proteinase-binding activity as those of human, alpha 2-macroglobulin was purified to homogeneity from mouse plasma. Even after additional purification steps, AMG still retains a growth-inhibitory activity and a more complex subunit structure than does human alpha 2-macroglobulin. AMG can inhibit the DNA synthesis of all types of murine tumor cells tested in vitro. This activity is cytostatic, dose dependent, and unaffected by the serum concentration in culture. Because this inhibitory activity is resistant to heat, pH 3, and methylamine, it is apparently unrelated to the proteinase-binding activity which is labile to all these treatments. Furthermore, in contrast to the proteinase-binding activity, the inhibitory activity can be partially removed from AMG by acid dialysis. Gel filtration of the dialysate yields two fractions (Mr 12,000 and 1,000 to 5,000) which potently inhibit murine tumor cells but stimulate both the B- and T-lymphocyte reactivities to mitogens in vitro. The growth-inhibitory activities in these fractions are resistant to digestions by chymotrypsin, RNase, and DNase. We conclude from this study that AMG does not inhibit tumor growth by virtue of its proteinase-binding activity; it may inhibit tumor cells via the small biomediators it carries.

Subunit and primary structure of a mouse alpha-macroglobulin, a human alpha 2-macroglobulin homologue.

A mouse alpha-macroglobulin (AMG), a homologue of human alpha 2-macroglobulin (alpha 2 M), has been purified to homogeneity. In contrast to human and acute-phase rat alpha 2 M which contains subunits of about Mr 190 000, the mouse protein contains two major (Mr 163000 and 35000) and one minor (Mr 185000) subunits. Also unlike human alpha 2 M, which can be broken down into about 85000-dalton subunits when reacted with an endopeptidase, the native AMG is cleaved by trypsin into multiple components (Mr 86000, 63000, 61000 and 33000). Two-dimensional peptide map analysis of these various 125I-labeled subunit components reveals that the 185000- and 163000-dalton components are homologous proteins but only the 185000-dalton protein contains the 35000-dalton component. The 163000-dalton protein is cleaved by trypsin into 86000- and 63000-dalton components, and the 86-kDa component in turn can be broken down into 61000- and 33000-dalton fragments. Since the 35000-dalton component is serologically related to AMG but does not share any tryptic peptides with both the 163000- and 33000-dalton components, it is neither a copurified impurity nor a cleavage product of the major (163000-dalton) subunit. AMG, therefore, is composed of covalently linked subunits of Mr 163000 and 35000, and the 185000-dalton protein may be a variant subunit of AMG. Trypsin treatment of the [14C]methylamine-labeled AMG and alpha 2 M also sequentially generate subunit patterns indistinguishable from those of the unlabeled macroglobulins. The methylamine-sensitive site(s) of AMG is localized in the 63000-dalton peptide, which is rather resistant to trypsin digestion and to staining by Coomassie brillant blue. We conclude from this study that the mouse homologue has a subunit composition and primary structure distinctly different from those of human and rat alpha 2 M.

Lack of adherence with the analgesic regimen: a significant barrier to effective cancer pain management.

PURPOSE: To evaluate oncology outpatients' level of adherence to their analgesic regimen during a 5-week period. PATIENTS AND METHODS: A random sample of 65 adult oncology outpatients with a Karnofsky performance status score of >or= 50, an average pain intensity score of >or= 2.5, and radiographic evidence of bone metastasis were recruited for this longitudinal study from seven outpatient settings. On a daily basis, patients rated their level of pain intensity and recorded pain medication intake. Adherence rates for opioid analgesics prescribed on an around-the-clock (ATC) and on an as-needed (PRN) basis were calculated on a weekly basis. RESULTS: Overall adherence rates for ATC opioid analgesics ranged from 84.5% to 90.8% and, for PRN analgesics, from 22.2% to 26.6%. No significant differences over time were found in either of these adherence rates. CONCLUSION: One factor that seems to contribute to ineffective cancer pain management is poor adherence to the analgesic regimen.

Vanishing bone metastases: a pitfall in contrast-enhanced CT in patients with venous thrombosis.

Enhancement patterns of visceral venous collaterals are well documented in cases of superior vena cava obstruction. Only recently has intraosseous venous collateral enhancement been described. We describe an unusual case of vertebral marrow enhancement in the lower thoracic spine related to venous collateral circulation caused by an incidental hemiazygos thrombus. Misinterpretation of this finding can lead to the erroneous interpretation of sclerotic bone metastases.

Human alpha 2-macroglobulin: a major serum factor cytotoxic for tumor cells.

Human alpha 2-macroglobulin (alpha 2M) was established here as a major serum factor which inhibits the DNA synthesis of a mouse ovarian tumor cell line in culture. This inhibitory activity was species non-specific, dose-dependent and unaffected by serum concentrations in culture. alpha 2 M was cytotoxic to both murine and human tumor cell lines in culture, as determined by 2 different viability staining techniques, morphological observation and long-term in vitro culture. This report implicates alpha 2 M or an alpha 2 M-associated substance as a major cytotoxic serum factor that may be involved in endogenous cancer control processes in mammalian species.

Return of potassium ion channels in regenerated hair cells: possible pathways and the role of intracellular calcium signaling.

Recent electrophysiological studies in pigeon have demonstrated that potassium channels are completely functional in regenerated type II hair cells at 21 days post-treatment (PT) with ototoxic doses of streptomycin. The currents return in the order they appear during development. The mixture of ionic currents in a regenerated type II hair cell in a particular region of the neuroepithelium is the same as in its ancestor in that region. The return of currents in regenerated type I hair cells is more complicated. The dominant conductance gKI is not present until after 70 days PT. Before 70 days, the ionic currents in type I hair cells resemble those of regenerated type II hair cells, suggesting that the ionic currents in type II hair cells might be precursors of the ionic currents in regenerated type I hair cells. New data show that at one year PT, the kinetics and drug sensitivity of the dominant K+ conductance in type I hair cells are identical to gKI. Supporting cells, believed to be the precursors of regenerated type II hair cells, have effectively no voltage-gated outward potassium channels, suggesting that regenerated type II hair cells must develop these channels de novo. The next step is to understand the mechanisms by which the potassium channel protein is synthesized, migrates through the cytosol, and is inserted into the plasmalemma of regenerating hair cells. These mechanisms are unknown. We propose that intracellular calcium is involved in this process, as well as in the differentiation, proliferation, and gene regulation of precursor cells fated to become hair cells.

Antibiotic prophylaxis in surgical procedures. A critical analysis of the literature.

The use of prophylactic antibiotics in surgery is widespread and often inappropriate. The lack of well-designed clinical studies partially explains the present confusion regarding the subject. We reviewed the literature in English on antibiotic prophylaxis through June 1982. Antibiotic prophylaxis reduces the incidence of wound infection after colorectal surgery, vaginal hysterectomy, and laryngeal and oropharyngeal resection for carcinoma, and in high-risk patients undergoing gastroduodenal or biliary surgery. In clean operations such as cardiac surgery, vascular procedures, and orthopedic surgery with placement of prostheses, the high morbidity associated with an infection justifies the use of antibiotics even though the risk of infection is small. There are conflicting data on the usefulness of prophylaxis in abdominal hysterectomy, cesarean section, noncardiac thoracic procedures, and urologic surgery. The effectiveness of prophylaxis in neurosurgery cannot be evaluated at the present time.

Optical imaging of anatomical maps derived from magnetic resonance images using time-independent optical sources.

We present a model suitable for computing images of absorption cross sections of thick tissue structures illuminated at near infrared (NIR) wavelengths from tomographic projection data. Image reconstruction is accomplished by solving a system of linear equations derived from transport theory. Reconstruction results using different algebraic solvers are shown for anatomical maps of the breast, derived from magnetic resonance imaging data, containing two simulated pathologies, in which case qualitatively good reconstructions were obtained. Evaluation of magnetic resonance (MR) data to optimize NIR optical tomographic imaging methods and to assess the feasibility of a combined MR-optical measurement scheme is discussed.

Antitumor effect of novel silatranes on renal cell carcinoma in mice.

The effect of several novel silatrane derivatives on the growth of syngeneic renal cell carcinoma (RENCA) in BALB/c mice and the survival rate of the animals were evaluated. The RENCA-bearing animals were treated subcutaneously and weekly with either a water-insoluble or a water-soluble derivative. The silatrane-treated animals were either free of palpable tumors or developed tumors much more slowly in comparison with the control animals without silatranes. The treated animals as a whole also died of tumor at much slower rates. Attempts to use higher silatrane dosages to achieve better curative effects were hampered by the toxicity of these compounds.

The effect of hyaluronan on osteoblast proliferation and differentiation in rat calvarial-derived cell cultures.

Hyaluronan (or hyaluronic acid, HA) is an essential component of extracellular matrices. It interacts with other macromolecules and plays a predominant role in tissue morphogenesis, cell migration, differentiation, and adhesion. The cell signaling functions of HA are mediated through the CD-44 receptor and are dependent upon the molecular weight of the polymer. We hypothesized that an HA of appropriate molecular weight alone in optimal concentration may induce osteoblast differentiation and bone formation. Enzyme-digested calvarial-derived mesenchymal cells from 2-day-old newborn rats were cultured with the addition of HA of three different molecular weights (2300, 900, and 60 kDa). We added, 0.5, 1.0, and 2.0 mg/mL HA for each molecular weight to the medium at the first plating of cells. After 7 to 20 days in culture, cell proliferation and differentiation were evaluated by measuring thymidine incorporation, alkaline phosphatase activity, and osteocalcin gene expression. The effects of HA on bone formation were examined by using Alizarin red staining for mineralization. The results showed that low molecular weight HA (60 kDa) significantly stimulated cell growth, increased osteocalcin mRNA expression in a dose-dependent manner, but showed no apparent effects on alkaline phosphatase activity and bone mineralization. On the other hand, high-weight HA (900 and 2,300 kDa) significantly increased all the parameters examined, particularly alkaline phosphatase activity, in a dose-dependent manner and stimulated cell mineralization to 126% and 119% of the controls, respectively, in the 1.0 mg/mL dose. Our findings suggest that HA has a molecular weight-specific and dose-specific mode of action that may enhance the osteogenic and osteoinductive properties of bone graft materials and substitutes due to its stimulatory effects on osteoblasts.

Asymmetric glucose uptake in leg muscles of patients with Multiple Sclerosis during walking detected by [18F]-FDG PET/CT.

BACKGROUND: In patients with Multiple Sclerosis (MS), comparative leg muscle strength asymmetries are common and typically accompanied by walking difficulties. Underlying mechanisms for these asymmetries are not completely known, but altered muscle energetics may play a role. OBJECTIVE: To investigate glucose uptake asymmetries in leg muscles of patients with mild MS during walking. METHODS: Eight MS and 8 healthy control (CON) participants performed a 15-min treadmill walking test at self-selected speed. They were injected with a glucose tracer (18F-FDG) two minutes into the test and immediately upon completion, underwent Positron Emission Tomography/Computed Tomography (PET/CT) imaging. RESULTS: MS group walked at a lower speed than the healthy control group (P < 0.01), however it was found that: 1) ([18F]-FDG) uptake in knee and hip flexors was higher compared to the CON group (P = 0.02); 2) the MS group exhibited asymmetrical strength of the knee flexors (P = 0.03); 3) [18F]-FDG uptake was significantly lower in the weaker knee flexors of patients with MS (P < 0.01). CONCLUSIONS: [18F]-FDG uptake and strength asymmetries in the legs of patients with MS indicate greater metabolic costs during activity, which may play a major role in premature muscle fatigability and subsequent impaired walking capacity.

Active drift stabilization in three dimensions via image cross-correlation.

By monitoring stage drift via the normalized cross-correlation of an image of a stuck bead, obtained in real-time, with an out-of-focus "template" image of a similar immobile bead, stored in memory, we implement a simple approach to actively stabilize drift in all three dimensions for existing video microscopy setups. We demonstrate stability to 0.0062 nm along the Z-axis and 0.0031 nm along the X- and Y-axes for long (100 s) timescales.

Growth and antigenic properties of a spontaneously regressing subline of leukemia L1210.

A subline (1210/MR) of the lethal parental L1210 leukemia cell line has been demonstrated to undergo dose-dependent spontaneous regression in both syngeneic and hybrid mice, although the regressing and non-regressing cells differed only slightly in growth rate. The regressed mice, like those actively immunized, were specifically protected from the subsequent challenge with L1210 cells. In addition, L1210/MR cells when coinjected could protect CD2F1 mice from low but lethal doses of L1210 cells. These two cell lines shared at least one cross-reacting cell surface antigen as determined by an isologous anti-L1210/MR immune serum. Such immune serum after being absorbed by L1210 cells still retained its in vitro complement-dependent cytotoxicity against L1210/MR cells. We conclude that the cell lines are antigenically related but L1210/MR cells may possess additional novel antigens, and that spontaneous regression of L1210 may be an L1210-specific immunological phenomenon.

Natural cytotoxins in human plasma: isolation and characterization of phospholipids associated with cytotoxic lipoproteins.

Most of the heat-stable natural cytotoxins in normal human plasma were fractionated by gel filtration into two active fractions: the alpha 2-macroglobulin (alpha 2M) and pre-alpha 2M pools. The pre-alpha 2M pool also appeared to contain most of the phospholipids in human plasma. The pre-alpha 2M pool was further purified by ultracentrifugation and was shown to contain cytotoxic lipoproteins that represented most of the cytotoxin activity in the pool. The phospholipids associated with the pre-alpha 2M pool and purified lipoproteins resisted dialysis in a buffered saline but were extractable by organic solvents. Two major phospholipids (compounds A and B) were extracted, and both exhibited cytotoxic activities. Compound A exerted dose-dependent, species-nonspecific growth-inhibitory or cytotoxic effects on tumor cells in vitro. It was a lecithin-like compound but was more potent than any of the lecithin standards tested, except for a polyunsaturated lecithin. The possibilities that certain lecithin-like compound(s) contribute significantly to the cytotoxic activity of the lipoproteins and their role in cancer resistance are discussed.

Interaction of nerve growth factor with murine alpha-macroglobulin.

The murine nerve growth factor, when injected i.v. or, combined in vitro with plasma, was found largely associated with the mouse alpha-macroglobulin (a homologue of human alpha 2-macroglobulin). The nerve growth factor-alpha-macroglobulin complex produced is sufficiently stable to resist separation by gel filtration in 1.0 M sodium chloride, polyacrylamide gel electrophoresis, and immunoprecipitation by antibodies against alpha-macroglobulin. As determined by equilibrium binding studies and computer generated Scatchard analysis, alpha-macroglobulin apparently possesses two types of binding sites with the apparent dissociation constants of 1.2 x 10(-6) and 2.9 x 10(-9) M, respectively, saturable by 3.7 and 0.03 moles of nerve growth factor. Hence, about one mole of nerve growth factor is bound to each of the four subunits of alpha-macroglobulin. Nerve growth factor can be readily dissociated from alpha-macroglobulin in sodium dodecyl sulfate gel electrophoresis in the absence of a reductant. Procedures that affect the proteinase-binding or methylamine- activities of alpha-macroglobulin do not affect the binding of nerve growth factor, and the binding is unaffected by the presence of zinc ions or EDTA. Hence, nerve growth factor is noncovalently associated with alpha-macroglobulin at a site separate from that of the proteinase-, methylamine-, and zinc-binding sites of alpha-macroglobulin. Mouse alpha-macroglobulin can protect the nerve growth factor from inactivation by trypsin. Even in the presence of trypsin, alpha-macroglobulin-nerve growth factor complexes still can stimulate the neurite outgrowth by dorsal root ganglia of 9-day-old chicken embryos. Since alpha-macroglobulin can specifically and noncovalently carry nerve growth factor, one important role of this alpha-macroglobulin in the circulation and extracellular spaces may be to protect the nerve growth factor from proteinase inactivation.