Matrix metalloproteinase 9 (92-kDa gelatinase/type IV collagenase) from HT 1080 human fibrosarcoma cells. Purification and activation of the precursor and enzymic properties

Matrix metalloproteinase 9 (MMP-9) has been purified as an inactive zymogen of M(r) 92,000 (proMMP-9) from the culture medium of HT 1080 human fibrosarcoma cells. The NH2-terminal sequence of proMMP-9 is Ala-Pro-Arg-Gln-Arg-Gln-Ser-Thr-Leu-Val-Leu-Phe-Pro, which is identical to that of the 92-kDa type IV collagenase/gelatinase. The zymogen can be activated by 4-aminophenylmercuric acetate, yielding an intermediate form of M(r) 83,000 and an active species of M(r) 67,000, the second of which has a new NH2 terminus of Met-Arg-Thr-Pro-Arg-(Cys)-Gly-Val-Pro-Asp-Leu-Gly-Arg-Phe-Gln-Thr- Phe-Glu. Immunoblot analyses demonstrate that this activation process is achieved by sequential processing of both NH2- and COOH-terminal peptides. TIMP-1 complexed with proMMP-9 inhibits the conversion of the intermediate form to the active species of M(r) 67,000. The proenzyme is fully activated by cathepsin G, trypsin, alpha-chymotrypsin, and MMP-3 (stromelysin 1) but not by plasmin, leukocyte elastase, plasma kallikrein, thrombin, or MMP-1 (tissue collagenase). During the activation by MMP-3, proMMP-9 is converted to an active species of M(r) 64,000 that lacks both NH2- and COOH-terminal peptides. In addition, HOCl partially activates the zymogen by reacting with an intermediate species of M(r) 83,000. The enzyme degrades type I gelatin rapidly and also cleaves native collagens including alpha 2 chain of type I collagen, collagen types III, IV, and V at undenaturing temperatures. These results indicate that MMP-9 has different activation mechanisms and substrate specificity from those of MMP-2 (72-kDa gelatinase/type IV collagenase).

[Urinary trypsin inhibitor as an acute phase reactant]

Early in this century, trypsin inhibiting activity has already been recognized in patients with acute infection or renal disease. In addition to these, conditions such as coronary thrombosis, surgical operation, artificial fever by heat-killed bacilli, malignancy, leukemia, later stage of normal pregnancy, etc. have been known to cause the elevated excretion of UTI in urine. Typically, maximal excretion of UTI has been observed within one or two days after the onset. It appears that recent studies have overcome the complexity of UTI molecule. Automated measurement of urinary trypsin inhibitor (UTI) in urine sample was carried out by either enzymic or immunologic method. UTI as well as erythrocyte sedimentation rate and C-reactive protein enables us to monitor acute phase response, being confirmed in cases of abdominal surgery.

Localization of matrix metalloproteinase 3 (stromelysin) in osteoarthritic cartilage and synovium

Degradation of proteoglycans is an initial change in osteoarthritic cartilage. Matrix metalloproteinase-3 (MMP-3; stromelysin) capable of degrading cartilage proteoglycans and type IX collagen was immunolocalized in osteoarthritic and normal cartilage. Immunohistochemical studies showed MMP-3 in chondrocytes of the superficial and transition zones in approximately 90% of osteoarthritic cartilage (60 of 67 samples) and in 31% of those of the superficial zone in some normal cartilage (4 of 13 samples). MMP-3 staining correlated directly with the histological histochemical scores of Mankin and with proteoglycan depletion, up to a certain grade of severity. Chondrocytes in the deep radial zone, clusters, and osteophytes were immunostained only when proteoglycan depletion and fissures affected them. Culture media from osteoarthritic cartilage contained significantly higher levels of metalloproteinase activity that was identified as MMP-3 by immunoblotting and lower amounts of tissue inhibitor of metalloproteinases compared with those in the control samples. MMP-3 was also immunolocalized in the lining cells of most osteoarthritic synovium (20 of 23 specimens, 87%) with a direct correlation with scores of inflammatory cell infiltration in the synovium, but it was not detected in the normal synovium. Light and electron microscopic studies demonstrated that MMP-3 digests proteoglycan aggregates in human articular cartilage. Treatment of normal and osteoarthritic cartilage slices with tumor necrosis factor-alpha and/or interleukin-1 alpha increased the number of MMP-3-immunoreactive chondrocytes and the intensity of the staining. These data suggest that MMP-3 produced by the chondrocytes and synovial lining cells under stimulation with these cytokines may be important in proteoglycan degradation in human ostoearthritic cartilage.

Response dynamics and receptive-field organization of catfish amacrine cells

1. We have applied Wiener analysis to a study of response dynamics of N (sustained) and C (transient) amacrine cells. Stimuli were a spot and an annulus of light, the luminance of which was modulated by two independent white-noise signals. First- and second-order Wiener kernels were computed for each spot and annulus input. The analysis allowed us to separate a modulation response into its linear and nonlinear components, and into responses generated by a receptive-field center and its surround. 2. Organization of the receptive field of N amacrine cells consists of both linear and nonlinear components. The receptive field of linear components was center-surround concentric and opposite in polarity, whereas that of second-order nonlinear components was monotonic. 3. In NA (center-depolarizing) amacrine cells, the membrane DC potentials brought about by the mean luminance of a white-noise spot or a steady spot were depolarizations, whereas those brought about by the mean luminance of a white-noise annulus or a steady annulus were hyperpolarizations. In NB (center-hyperpolarizing) amacrine cells, this relationship was reversed. If both receptive-field center and surround were stimulated by a spot and annulus, membrane DC potentials became close to the dark level and the amplitude of modulation responses became larger. 4. The linear responses of a receptive-field center of an N amacrine cell, measured in terms of the first-order Wiener kernel, were facilitated if the surround was stimulated simultaneously. The amplitude of the kernel became larger, and its peak response time became shorter. The same facilitation occurred in the linear responses of a receptive-field surround if the center was stimulated simultaneously. 5. The second-order nonlinear responses were not usually generated in N amacrine cells if the stimulus was either a white-noise spot or a white-noise annulus alone. Significant second-order nonlinearity appeared if the other region of the receptive field was also stimulated. 6. Membrane DC potentials of C amacrine cells remained at the dark level with either a white-noise spot or a white-noise annulus. The cell responded only to modulations. 7. The major characteristics of center and surround responses of C amacrine cells could be approximated by second-order Wiener kernels of the same structure. The receptive field of second-order nonlinear components of C amacrine cells was monotonic.(ABSTRACT TRUNCATED AT 400 WORDS)

Lactate analyzer with continuous blood sampling for monitoring blood lactate during physical exercise

To monitor changes in the concentration of blood lactate during physical exercise, we used an automated lactate analyzer based on an electro-enzymatic method with continuous blood sampling through a catheter. The lactate concentration was measured every 2 min; between measurements, the instrument was calibrated with a lactate standard. Ascorbic acid, bilirubin, hemoglobin, creatinine, uric acid, and glucose did not interfere with the measurements. The lactate concentrations in blood samples from apparently healthy subjects before and after exercise correlated well (r = 0.993) with results by the conventional enzymatic method. We measured the blood lactate concentrations in nine apparently healthy volunteers during exercise on a treadmill with an increasing workload. The point at which lactate concentrations started to increase was detected easily. Thus, the lactate analyzer is suitable for monitoring changes in blood lactate concentrations during exercise.

Lactate analyzer with continuous blood sampling for monitoring blood lactate during physical exercise

To monitor changes in the concentration of blood lactate during physical exercise, we used an automated lactate analyzer based on an electro-enzymatic method with continuous blood sampling through a catheter. The lactate concentration was measured every 2 min; between measurements, the instrument was calibrated with a lactate standard. Ascorbic acid, bilirubin, hemoglobin, creatinine, uric acid, and glucose did not interfere with the measurements. The lactate concentrations in blood samples from apparently healthy subjects before and after exercise correlated well (r = 0.993) with results by the conventional enzymatic method. We measured the blood lactate concentrations in nine apparently healthy volunteers during exercise on a treadmill with an increasing workload. The point at which lactate concentrations started to increase was detected easily. Thus, the lactate analyzer is suitable for monitoring changes in blood lactate concentrations during exercise.

The messages in optic nerve fibers and their interpretation

Spike discharges are the principal carriers of information in the nervous system. Although both the ionic and the molecular mechanisms of spike generation have been studied extensively, the methods for analyzing a spike train that are currently employed have not changed much from those in use 20 years ago. There is an apparent need for a refinement of the methods used to analyze spike trains. We present here a summary of our recent results of an analysis of spike trains from retinal ganglion cells that is based on Wiener's theory of non-linear analysis or white-noise analysis. We found that spike trains carry, at least to a second-order approximation, as much information as is carried by the ganglion cell's postsynaptic potential (PSP). There is no loss of information when an analog signal, PSP, is converted into a point process, namely, spike discharges. It is indeed possible to predict the cell's PSP from a spike train. This finding has two important implications. First, the neuron network in the retina produces a PSP, the dynamics of which are optimal for triggering a spike discharge, or conversely, the spike-generation mechanism is optimized to match the dynamics of the network. The external stimulus that is optimal for production of a ganglion-cell discharge is represented as the cell's PSP. Second, there is structure encoded within the spike train; information on a second-order non-linearity is encoded by the relative timing of two consecutive spike discharges. Coding of non-linearity into a spike train is an efficient means of signal compression and is an important aspect of neurophysiology.

Sensitivity transformation for vertebrate vision

The visual response to a flash given in the dark is known to saturate according to the Michaelis-Menten relationship. Nevertheless, the incremental response from increasing levels of mean luminance tends to follow a Weber-Fechner relationship well into the saturation range determined from the Michaelis-Menten results. This sensitivity transformation from Michaelis-Menten to Weber-Fechner is an important characteristic of light adaptation in the vertebrate retina. Recent studies concerning the role of calcium in photoreceptor adaptation have shown that the relaxation from peak to plateau in the response of isolated photoreceptors was absent under conditions in which adaptation was blocked. Comparing the pronounced relaxation from peak to plateau in turtle horizontal cells with the absence of such relaxation in the catfish response, we noted also that turtle incremental sensitivity shows a Weber-Fechner relationship while catfish incremental sensitivity more closely follows the local slope of the Michaelis-Menten relation. Based on these observations, we have obtained an expression to relate the relaxation from peak to plateau with the sensitivity transformation. We assume that adaptation shifts the half-maximum point of the Michaelis-Menten curve so that the light response relaxes to a plateau value equal to a specified fraction phi of the peak response. We show that this manipulation alone results in a transformation from Michaelis-Menten kinetics to Weber-Fechner sensitivity.

Clinical significance of urinary laminin P1 in diabetic patients

The urinary concentrations of laminin fragment P1 (L-P1), a major component of laminin, were determined in diabetic patients without diabetic nephropathy and healthy controls. In the control subjects, urinary L-P1 increased with age, especially over 60 years of age. A significant increase of urinary L-P1 was observed in diabetics aged less than 50 years. Neither urinary albumin nor N-acetyl-beta-D-glucosaminidase correlated to the urinary L-P1 level. We used immunohistochemistry to locate L-P1 in the cortex of human kidneys. In non-diabetic kidneys, the glomerular and tubular basement membranes, mesangium, and Bowman's capsule were stained. In the diabetic kidney, more was stained, including the mesangial expansion and the thickened capillary basement membranes.

localization of type VI collagen in the lining cell layer of normal and rheumatoid synovium

Types I to VI collagens were immunolocalized in normal and rheumatoid synovium using monospecific antibodies. Immunofluorescence studies showed type VI in the extracellular matrix of the lining cell layer, whereas positive staining for type III collagen was observed in both the lining and sublining cell layers. All other collagens could not be detected in the lining cell layer. Immunogold staining of the rheumatoid synovium localized type VI collagen to filamentous material, which was the major extracellular structure of the lining cell layer. Type III collagen was associated with thin cross-striated collagen fibrils. A brief treatment of rheumatoid synovial tissue with bacterial collagenase produced in the lining cell layer numerous broad-banded fibrils with 100-nm periodicity; these fibrils could be labeled with the antibody against type VI collagen. This suggests that type VI collagen filaments have the potential to form periodic structures under certain conditions. We further studied the susceptibility of type I to VI collagens to matrix metalloproteinase 1, 2 and 3 (collagenase, gelatinase of molecular weight 72,000, stromelysin), which are secreted by synovial lining cells in rheumatoid synovium, and found only type VI collagen to be completely resistant to all these metalloproteinases. These data indicate that type VI collagen, which has the ability to bind to cells and to interstitial collagens, plays an important role in supporting the synovial lining cells in the normal and rheumatoid synovium.

The effect of non-insulin-dependent diabetes on serum concentrations of tumor-associated carbohydrate antigens of CA19-9, CA-50, and sialyl SSEA-1 in association with the Lewis blood phenotype

Serum concentrations of the tumor-associated carbohydrate antigens CA19-9, CA-50, and sialyl SSEA-1 were measured in non-insulin-dependent diabetic patients without diseases causing the elevation of those antigens, and the relationship to diabetic conditions was studied. The patients of the Lewis blood group phenotype of Lea (23%) had higher serum CA19-9, CA-50, and sialyl SSEA-1 than those of Leb (67%) and Le(-) (10%). Lea patients with high HbA1c (greater than 10%) had significantly higher serum CA19-9 and CA-50 than those with low HbA1c (less than or equal to 7%). Leb patients with high HbA1c also had elevated CA19-9 and sialyl SSEA-1. In Leb patients, diabetic nephropathy was associated with increased CA19-9 levels. Diabetic retinopathy was also accompanied by high carbohydrate antigens in Leb patients, but the difference was not significant. Leb patients treated with sulfonylurea or insulin had increased CA19-9 and CA-50. The changes in serum concentrations of these carbohydrate antigens might have some relationship not only to the Lewis blood phenotype, but also to diabetes.

Removal of immunosuppressive substance in cancer patients' serum

Anemia-inducing substance (AIS) appears in plasma as cancer progresses. In this study, a non-coated charcoal column was used to remove AIS from the cachectic plasma obtained from patients with advanced cancer. AIS could be completely removed by 6 cycles of adsorption using this column. Similar data were obtained in an experiment using VX-2-transplanted rabbits. These observations raised the possibility that plasmapheresis with a non-coated charcoal column may be available as a new means of immunotherapy for advanced cancer.

Automated measurement of trypsin inhibitor in urine with a centrifugal analyzer: comparison with other acute phase reactants

Automated measurement of trypsin inhibitor in urine was performed with good precision using the COBAS FARA. Elevated levels of both trypsin inhibitor in urine and acute phase proteins in serum were shown in most cases of major abdominal surgery. We suggest that the automated assay of urinary trypsin inhibitor might be useful for the clinical diagnosis of acute phase response.