The authors report an exceptional glomus tumor location in Hoffa's ligament in a 65-year-old man. Based on this observation and a literature review, the authors provide the clinical and radiographic diagnostic appearances of this type of tumor. Surgical removal of the tumor achieved immediate disappearance of knee pain. Histological examination of the tumor has established the definitive diagnosis.

"“20 Ans de Biomecanique Chez Renault”." Archives of Physiology and Biochemistry, 103(3), p. C38

The possible transformation of synovial osteochondromatosis into chondrosarcoma is rarely reported in the literature, as well as the coexistence of the two entities. The authors have observed two such cases. The first one was discovered by arthroscopy in the course of a synovial osteochondromatosis associated with a posterior tumour proved secondarily as being a chondrosarcoma. On the contrary, the second case presented as a destroying tumour invading the entire joint and proved secondarily as being a benign osteochondromatosis. Cartilaginous masses very important may lead to bone destruction in the course of benign osteochondromatosis. However, in such cases, the possibility of an associated or a secondary chondrosarcoma must be looked for using radiology, arthroscopy and microscope examination.

Fifty-six renal transplanted patients having an average age of 33 years have been operated on for necrosis of the femoral head from 1973 to 1988. They totalise 85 cephalic necrosis due to the therapeutic peaks of corticotherapy. The femoral condyles were affected by the necrosis in 21 patients, and the humeral head in 16 patients. 82 surgical operations of first intention and 18 resumptions leading to 100 the total number of operations. The 26 drilling gave place to 11 by arthroplasty. The good results of the drillings only concern the infraradiological stages and the MRI allows to detect the non symptomatic stages 0. The 33 intermediate prosthesis did not lead to septic complications but 9 cotiloidal alterations of which 4 important with a resumption by total prosthesis. 36 total prosthesis were realized out of which 13 for resumption. Two early and two late suppurations after septicemia complicated the evolution. If at stage 0 or 1 the drilling seems to remain a reliable indication, the total prosthesis is the only possible solution for invalidating stages IV, the intermediate prosthesis seems to be able to keep a place in the intermediate stages.

The theory of alternative substrates has been thoroughly investigated. The reciprocal rate equations, for ordered and random kinetic mechanisms, in the presence of an alternative substrate, have been developed. The conditions in which those equations give rise to either hyperbolic or linear reciprocal plots have been established. Degeneracy and constraint conditions of the various kinetic models have also been derived. Definite conclusions concerning the relevant mechanism can be obtained only if the Dalziel coefficients pertaining to the substrate are different from those corresponding to the alternative substrate. It follows from this, that the method termed “isotope competition”, cannot be used to make a choice among various two‐substrate mechanisms, and appears to be unfounded. The theory of alternative substrates has been applied to the study of yeast hexokinase. The results obtained are at variance with a random mechanism. They do agree, on the other hand, with a compulsory order of substrate binding on the enzyme, glucose being bound first.

The ionic species ATP 4− and Mg 2+ , at high concentrations, decrease the rate of glucose phosphorylation catalyzed by yeast hexokinase. A theoretical study of all the possible mechanisms (271 models) of this inhibition has been made. The comparison of these mechanisms with the experimental results shows that only one model can explain the inhibition of the reaction by ATP, and that only one can also explain the effect of the high magnesium concentrations. It was thus possible to show that the ionic species ATP 4− can be bound on hexokinase and on the hexokinase‐glucose complex. Its affinity is much stronger for the second form of the enzyme than for the first. The complexes thus formed are devoid of any activity (“dead‐end” complexes). The inhibition of the hexokinase by the high nucleotide concentrations is therefore due to the formation of these complexes. A ternary chelate of the Mg(ATP) 2 6− type does not exist. Magnesium possesses no affinity for the enzyme. Its role in the catalysis must therefore by indirect. The results presented agree with the idea that the metal polarizes the phosphoryl bond of the ATP that is split when glucose‐6‐phosphate is formed. Magnesium can form with ATP a ternary chelate of the Mg 2 ATP type, unable to be bound on the hexokinase. The inhibiting effect of high concentrations of the metal can be explained by the formation of this inactive ternary chelate and by the decrease in concentration of the MgATP 2− complex.

A hexokinase has been isolated from Baker's Yeast, purified and obtained in crystalline form. Its specific activity is between 600 and 700 units/mg. This enzyme is homogeneous on DEAE‐cellulose chromatography. The molecular weight, estimated by molecular sieving on Sephadex G‐100, is around 49000.The authors of the present article have been able to show, by equilibrium dialysis on Sephadex G‐25, that one molecule of the enzyme (MW 49000) binds one molecule of [14C]glucose in the absence of ATP. The value of the affinity constant for [14C]glucose, under the experimental conditions used and in the absence of ATP, is 10000 M–1. This value is nearly identical, within experimental errors, to 1/Km obtained from the measurement of hexokinase activity.The binding of the Mg[14C]ATP2– chelate on the enzyme cannot be detected in the absence of glucose and under the experimental conditions used. This result implies that the affinity constant of the hexokinase for MgATP2– is lower than 800 M–1. The value of 1/Km for the ATPase reaction, determined under the same experimental conditions, is around 200 M–1.These results are compatible with an ordered mechanism of hexokinase catalysis, in which the enzyme binds glucose first. They seem difficult to reconcile with a rapid equilibrium random mechanism.

The frequent occurrence of protein anomalies in patients with myelomatosis has long been recognized.Bence Jones reported on the unusual urinary protein of a patient with this disease over a hundred years ago (Bence Jones, 1848).Hyperproteinaemia in myelomatosis was recorded somewhat later (Ellinger, 1899).Subsequently, electrophoretic studies have shown that the hyperproteinaemia is due to the presence in serum of a protein or proteins apparently absent from normal serum.In the past decade, however, it has become increasingly evident that anomalous protein components in serum or urine are not restricted to myelomatosis but occur in various other conditions.Such components have been the subject of many investigations, and it is the aim of this review to summarize current views on the nature and significance of these proteins.Occurrence of Anomalous Serum and Urinary Proteins For the present purpose, anomalous proteins are defined as those which appear as discrete abnormal components in the electrophoretic patterns obtained with conventional techniques, viz., boundary electrophoresis or zone electro- phoresis on paper.A number of names, based either on the circumstances in which they are found or on their chemical properties, have been given to such proteins occurring in serum.Thus those found in myelomatosis are termed myeloma proteins, those with high molecular weights are termed macroglobulins, whilst those which precipitate on cooling are termed cryoglobulins.The use of such terms, however, tends to obscure the many affinities of these proteins.Anomalous urinary proteins comprise Bence Jones proteins.Conditions in which anomalous proteins have been found fall into three groups, namely neoplastic disease, idiopathic haemolytic disease, and miscellaneous conditions.Neoplastic Disease.-Byfar the commonest conditions associated with anomalous proteins are myelomatosis and lymphoma.About 80% of patients with myelomatosis have anomalous electrophoretic components in their sera; a smaller proportion of cases excrete Bence Jones protein in the urine (for references see Owen and Rider, 1957).Lymphoma (using this as a generic term to include conditions designated more precisely lymphosarcoma, reticulum cell sarcoma, or Hodgkin's disease) is less frequently associated with anomalous serum components, although many instances have been recorded (e.g., Mackay,

HÆMOGLOBIN and complexes of serum haptoglobins with hæmoglobin, have peroxidase-like activity which permits their detection in small amounts. For this purpose benzidine1,2, o-tolidine2, guaiacol3 and leucomalachite green4 have been employed. However, none of these substances has proved entirely satisfactory. The colours given by benzidine and tolidine fade within minutes5, especially when applied to starch-gel strips, and both reagents give appreciable background staining on paper. Instability of benzidine and guaiacol colours used to detect horse-radish peroxidase after paper electrophoresis has been noted also by Jermyn and Thomas6, who reported that o-anisidine, p-aminodimethylaniline and hydroquinone were even less satisfactory as reagents for the detection of peroxidases. Malachite green, formed from leucomalachite green, is more stable; but we have found the reagent much less sensitive than either benzidine or tolidine.

Heterogeneity of myelomatous and nonmyelomatous monoclonal IgG1 proteins was investigated by isoelectric focusing experiments in thin-layer polyacrylamide gels.It appears from this study that nonmyelomatous monoclonal IgG1 proteins possess the same individuality and limited heterogeneity as myelomatous monoclonal IgG1 proteins.