A new method of preparing and some properties of high molecular weight monoamine oxidase from swine liver mitochondria

Isolation of highly purified and highly molecular monoamine oxidase (MAO) from pig liver mitochondria have been worked out. Specific activity of isolated preparation is 2700 times higher than of original mitochondria homogenate. Enzyme solubilization by digitonin, affinity chromatography purification and ultrafiltration underlie this method. MAO catalytic properties changing during the process of purification by different methods have been investigated. Substrate specificity was studied; kinetic parameters of enzymatic desemination were calculated.     

Dosimetric analysis of chimeric monoclonal antibody cMOv18 IgG in ovarian carcinoma patients after intraperitoneal and intravenous administration

In this study the potential of intraperitoneal (i.p.) and intravenous (i.v.) administration of chimeric iodine-131-labelled MOv18 IgG for radioimmunotherapy was determined. The dosimetry associated with both routes of administration of cMOv18 IgG was studied in patients. Eight patients suspected of having ovarian carcinoma received 150 MBq 131I-cMOv18 IgG i.p. Blood and urine were collected and serial gamma camera images were acquired. Another group of four patients received 7.5 MBq 131I-cMOv18 IgG i.v. For all patients, tissue biopsies were obtained at surgery. Activity in the blood after i.p. administration was described by a bi-exponential curve with a mean uptake and elimination half-life of 6.9+/-3.2 h and 160+/-45 h, respectively. For i.v. infusion the mean half-life for the elimination phase was 103+/-12 h. Cumulative excretion in the urine was 17%+/-3% ID and 21%+/-7% ID in 96 h for i.p. and i.v. administration, respectively. Scintigraphic images after i.p. administration showed accumulation in ovarian cancer lesions, while all other tissues showed decreasing activity with time. Tumour uptake determined in the ovarian cancer tissue specimens ranged from 3.4% to 12.3% ID/kg for i.p. administration and from 3.6% to 5.4% ID/kg for i.v. administration. Dosimetric analysis of the data indicated that 1.7-4.3 mGy/MBq and 1.7-2.2 mGy/MBq can be guided to solid or ascites cells after i.p. and i.v. administration, respectively. Assuming that an absorbed dose to the bone marrow of 2 Gy will be dose limiting, a total activity of 4.1 GBq 131I-cMOv18 IgG can be administered safely via the i.p. route and 3.5 GBq via the i.v. route. At this maximal tolerated dose, a maximum absorbed dose to 1-g tumours in the peritoneal cavity of 18 and 8 Gy can be reached after i.p. and i.v. administration, respectively. For the i. p. route of administration, dose estimates for the tumour are even higher when the electron dose of the peritoneal activity is also taken into account: total doses to the tumour of 30 Gy and 22 Gy will be absorbed at the tumour surface and at 0.2 mm depth, respectively. In conclusion, therapeutic tumour doses can be achieved with 131I-cMOv18 IgG in patients with intraperitoneal ovarian cancer lesions with no normal organ toxicity. The i.p. route of administration seems to be preferable to i.v. administration.     

Differential expression and functionally co-operative roles for the retinoblastoma family of proteins in epidermal differentiation

Terminal differentiation requires cell cycle withdrawal, suggesting the involvement of negative cell cycle controllers in the process. We have analysed the involvement of the retinoblastoma family of proteins (pRb, p107 and p130) in epidermal proliferation and differentiation. These proteins play key roles as inhibitors of cell cycle progression and are involved in muscle and neuron differentiation. We found that during in vitro differentiation of human HaCaT keratinocytes, pRb, p107 and p130 are sequentially expressed, in contrast to the co-expression observed during cell cycle progression in the same cells. Immunofluorescence studies on skin sections revealed the presence of pRb and p107 in basal and suprabasal cell layers, whilst p130 is restricted to cells already committed to differentiation in the suprabasal compartments. To explore the functional significance of the differential expression of these proteins, transfection experiments were performed in HaCaT keratinocytes. We observed that the forced over-expression of pRb, p107 or p130 individually did not induce differentiation of the transfected cells. However, the co-transfection of pRb and p107 induced the expression of early differentiation markers (keratin k10) and triple transfectants pRb+p107+p130 expressed markers representative of later stages of epidermal differentiation (involucrin). Finally, we observed that these three proteins repress keratinocyte proliferation, although to a different extent (p107>pRb> or =p130). These results indicate that the members of the pRb family play specific, yet coordinated roles during epidermal differentiation, and that the ordered progression along the different stages of this process results from the effects of different combinations of these proteins.     

Surgical treatment of degenerative mitral regurgitation

Karyotypes were prepared from peripheral blood leukocytes in 77 couples in whom there was no apparent cause for recurrent spontaneous abortion. In addition to conventional staining, chromosomes were stained by the new technics for Q-, G-, or C-banding. Translocations were found in 5 of 154 persons (3.25% or 1:31 individuals). The frequency of translocations in the general adult population is 0.4% (1:255). Two translocations were apparent only with the new technics for banding. The incidence of chromosomal microanomalies was 7.79% (2.6% in the general population). Karyotyping of couples with recurrent abortion is recommended, with use of the new staining technics.     

Purification and characterization of two forms of urokinase

Affinity chromatography on agmatine-Sepharose was used for the separation of two active forms of urokinase (EC 3.4.99.26) from partially purified human urinary urokinase. The approximate molecular weight of the heavier form was 47 000 and of the lighter 33 400. Both forms were homogeneous by sodium dodecyl sulfate gel electrophoresis and by 3H-labeled diisopropylphosphorofluoridate and 14C-labeled p-nitrophenyl-p'-guanidinobenzoate incorporation studies. The 33 400 mol. wt. form had a single chain, and the 47 000 mol. wt. form had two chains (33 100 and 18 600 mol. wt.) linked by disulfide bonds. The specific activity of the heavier form was 104 000 CTA units/mg protein, compared with 226 000 units/mg for the lighter form but the activities per mmol of active site (molar activities) of the two forms were almost identical (9.6-10(9) and 10.2-10(9) CTA units/mmol). Isoelectric focusing on gels showed that the 47 000 material contained one major subform with a pI of 8.60 and a minor subform with a pI of 8.90, while the 33 400 material had three major subforms with pI values of 8.35, 8.60 and 8.70, respectively, and a minor subform with a pI of 8.05. 3H-labeled diisopropylphosphorofluoridate incorporation studies revealed an active-site serine residue in the heavy chain.     

Dexamethasone 21-mesylate: an affinity label of glucocorticoid receptors from rat hepatoma tissue culture cells

We recently described the biological properties of an alpha-keto mesylate derivative of cortisol, cortisol-Mes. Cortisol-Mes exhibited long-term antiglucocorticoid activity, but there was no firm evidence that this activity was irreversible or receptor-mediated. Here we report that dexamethasone mesylate (Dex-Mes), which is the alpha-keto mesylate derivative of the more active glucocorticoid dexamethasone, is a candidate for a steroid-specific affinity label of glucocorticoid receptors. Dex-Mes is relatively stable, like cortisol-Mes, but possesses greater whole-cell antiglucocorticoid activity. However, Dex-Mes also possesses partial agonist activity, which is expressed at somewhat higher concentrations of Dex-Mes than the antagonist activity. Dex-Mes is more efficient than cortisol-Mes in competing for dexamethasone binding to glucocorticoid receptors. Furthermore, Dex-Mes is effective at lower concentrations than cortisol-Mes in causing long-term apparently irreversible antiglucocorticoid effects in whole and broken cells. The cell-free effect of Dex-Mes is specifically prevented by coincubation with an excess of cortisol. These facts argue that the apparently irreversible effects of Dex-Mes are steroid mediated. [3H]Dex-Mes has been used to identify a glucocorticoid-specific, covalently labeled fraction on sodium dodecyl sulfate/polyacrylamide gels with a molecular weight of approximately 85,000. Thus Dex-Mes appears to have been established as an affinity label for glucocorticoid receptors.