Otto Wegelius

Human leukocyte collagenase: Characterization of enzyme kinetics by a new method

Abstract Human collagenase was partially purified from polymorphonuclear leukocytes, and a new method for assay of the collagenase activity was developed. The assay employs native radioactive collagen in soluble form as a substrate. The enzyme incubations are performed at 25°C which is below the melting temperatures of the cleavage products TCA and TCB, and these peptides are quantitatively recovered by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Employing this method, an apparent K m value of 1.04 × 10 −6 m for human leukocyte collagenase using type I collagen as a substrate was measured.

Isolation and characterization of undersulphated chondroitin-4-sulphate from normal human plasma

The present study was undertaken in order to characterize further the glycosaminoglycans of normal human plasma. Coagulation factor IX concentrate prepared from undiluted plasma by DEAE-Sephadex chromatography was used as the starting material. The concentrate was subjected to proteolytic treatment with papain and pronase, deproteinised with trichloroacetic acid, dialysed and passed through an AG 1 X 2 anion-exchange column. Glycosaminoglycans were eluted stepwise from the column with NaC1. The sole glycosaminoglycan obtained was an undersulphated chondroitin-4-sulphate which was identified by chemical analyses, digestibility with testicular hyaluronidase, electrophoretic behaviour and infrared spectrum. Gel-exclusion chromatography indicated a molecular weight of 17 000 for the compound. The undersulphated chondroitin-4-sulphate was calculated to represent at least 80% of the macromolecular glycosaminoglycans present in normal human plasma and to occur in a concentration of approx. 3 mg hexuronate per 1 of plasma.

Sjögren's Syndrome Associated with Vitamin B12 Deficiency

Three patients showing Sjögrens syndrome in association with macrocytic anemia due to vitamin B(12) deficiency are described. Antibodies to parietal cells, intrinsic factor and salivary protein were investigated; positive test results were obtained in different combinations. Addisonian pernicious anemia as well as vitamin B(12)-malabsorption because of anti-intrinsic factor antibodies in gastric juice and/or malabsorption due to changes in the intestinal wall induced by Sjögrens syndrome are possible etiological factors. A case of Sjögrens syndrome associated with positive anti-parietal cell antibodies and histaminerefractory achylia is also reported. The concurrence of these two diseases known to be associated with autoimmune responses suggests the possibility of similar pathogenesis.

Increased collagenase activity in human rheumatoid meniscus.

Collagenase activity of the knee joint menisci of patients suffering from rheumatoid arthritis was approximately 3-fold higher than that found in menisci of control patients. The mean collagenase activity in the macroscopically more diseased parts of the rheumatoid menisci was significantly higher than that in the less damaged areas. The specific degradation products resulting from the cleavage of human meniscoid type II collagen by rheumatoid meniscoid collagenase were demonstrated by SDS-polyacrylamide gel electrophoresis. Addition of N-ethylmaleimide, which activates latent mammalian collagenases, did not further increase collagenase activity in rheumatoid menisci. Thus in rheumatoid meniscus, collagenase may be synthesized and then activated, probably by proteolytic enzymes involved in the inflammatory reaction.

Collagenolytic activity in rheumatoid synovial tissue

Abstract Collagenolytic activity in synovial tissue was studied by measuring the degradation of collagen in normal and rheumatoid synovial tissue samples. In the assay the 6000-g pellet of the tissue homogenate was incubated in neutral buffer in the presence of Ca2+ at 37° for 20 h. Released hydroxyproline-containing material was taken as the measure of collagenolytic activity. The mean value of collagenolytic activity in the rheumatoid arthritis group was about 6–7 times that of controls. High values were found in patients having elevated rheumatoid factor titres. The increased collagenolytic activity in rheumatoid synovial tissue suggests increased breakdown of collagen in the diseased synovium. The high collagenolytic activity in the synovium may be connected with the local tissue destruction in the joint.

Effect of Thyroxine, Thyrotrophic and Somatotropic Hormones on Skin of Dwarf Mice.

Summary Dwarf mice and their normal siblings were given thyroxine, thyrotrophic and somatotropic hormones or physiological saline intraperitoneally. In the skin the mast cells were counted and concentration of hexosamine and hydroxyproline were determined. The number of mast cells did not show any significant variation in the different groups. Concentration of hexosamine in the skin of thyrotrophin-treated dwarf mice was significantly higher than concentration in control dwarf mice. Hexosamine values in the group of thyroxine-treated mice were higher than in the group of control mice. Hydroxyproline content was significantly higher in the skin of thyrotrophin-treated dwarf mice than in thyroxine-treated dwarf mice.

Lysosomal enzymes in regenerating rat liver.

Summary The concentration of the lysosomal enzymes acid phosphatase, arylsulfatase B and β-glucuronidase, was determined in regenerating liver 1, 2, 3, and 10 days after partial hepatectomy. An obvious increase in enzymatic activity was observed 2-3 days after the operation, but the reactions of the different enzymes were not parallel. It is concluded that the lysosomal organelle as such does not participate in the initiation of the process of cell division. The enzymatic activities seem to be at their maximum at a point of time subsequent to mitotic division. The present results argue in favor of the view that the lysosomes play a part in a postmitotic autophagocytosis. It is suggested that the lysosomal enzymes are involved in the inhibition of the regeneration of the liver.

Skin response to intradermal dna and rna in systemic lupus erythematosus

The local response of 18 patients with active systemic lupus erythematosus to 0.1 ml of intradermally injected 0.1% polymerized calf thymus DNA and synthetic double-stranded polyinosinic-polycytidylic acid was studied. In 14 patients positive for DNA, 61 ± 8% of the inflammatory cells in the subepidermis at 24 hours were acid alpha-naphthyl acetate esterase–positive T lymphocytes. A leukocytoclastic vasculitis was observed in the deeper dermis. Rheumatoid arthritis patients and acne patients had negative responses. These results indicated an abnormal cellular and humoral in vivo response by patients with systemic lupus to DNA. It is suggested that the epidermal Langerhans cells were responsible for the topographic dichotomy of the local DNA response. Test results were positive for polyinosinic-polycytidylic acid in 12 patients, for DNA in 14 patients, and for both in 9 patients. In the 9 patients with positive results for both tests, comparison of responses to each test indicated that the reaction intensity was dependent on the patient and not on the type of polynucleotide acid that was injected.

Reversible acute renal failure complicating rheumatoid arthritis.

Although morphological and functional kidney lesions are well known to occur in rheumatoid arthritis (RA), there appear to be no previous reports on reversible acute renal failure. That interstitial nephritis plays a part in acute renal failure is clinically documented but the pathophysiology is obscure. The role of raised interstitial pressure has often been discussed but convincing evidence is still lacking. Two patients with classical RA complicated by reversible oliguria and impaired kidney function are presented. Renal biopsies revealed no glomerular, tubular or amyloid lesions. The only light microscopic finding was greatly increased interstitial edema, which stained metachromatically with toluidine blue and was hyaluronidase-sensitive. It is supposed that the abnormal concentration of interstitial hyaluronic acid and its high water-binding capacity leads to an increase of interstitial pressure, which is followed by renal insufficiency. The mucinous edema of the kidneys is assumed to be an acute reaction of the pathological connective tissue in general.

Clearance of 125I-Labelled Urographin from Knee Joints in Rheumatoid Arthritis

(125)I-labelled Urographin has been used intra-articularly as tracer and 60 per cent Urographin as contrast in ten knee joints of patients with classical rheumatoid arthritis. Nine traumatic knees served as controls. The rapid rate of disappearance of the contrast from joints with rheumatoid inflammation was higher than in controls. Over the rheumatoid joints the radioactivity had decreased to half the initial value in 2.85 hrs. and over the traumatic joints in 3.70 hrs. In the radiographs clear evidence of absorption of contrast by the synovial membrane, the hyaline cartilage and the fibrocartilaginous tissue of the menisci was demonstrated. In one case visual proof was obtained of drainage of the contrast through the local lymphatics. The series of arthrograms taken from this knee indicate that this drainage was rapid.