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Biomedical subjects

G Murphy

Publications and source records attributed to G Murphy.

At least 415 records · Page 23Linked to original sources
PubMed1982

Langur monkey (Presbytis entellus) development. The first 3 months of life.

Observation for the first 3 months of life of 19 Indian langur monkey infants (Presbytis entellus) living in well-established colony social groups revealed complex and related patterns of social development. This is a period of rapidly increasing infant motor ability and increasing infant-initiated independence. Infant transfer, a behavior initiated by others towards the infant and a characteristic of the species, occurs most frequently in weeks 1 and 2, then steadily declines to low frequency in weeks 11 and 12. Infants are not punished or rejected, and to the extent the mother allows, the infant leaves her. She leaves her infant infrequently. The infant widens its radius of activity and increases the kinds and frequency of active interactions it has with others in the group. Patterns of behavior appear to develop in tandem during key periods of early life. Week 1 is the time of greatest dependence with 100% contact at first. During weeks 3 and 4, the infant efficiently expresses itself and can actively prevent transfers. Week 4 sees a constellation of major changes and a rising infant drive for independence. Play increases as do interactions with other immatures. Carrying decreases as the infant is able to follow. Some restraints are observed because of a new set of infant management problems presented to the mother. Throughout the first 3 months of life the mother is the focus of her infant's attention and activities--she is crucial to its survival. The 3-month-old infant is an active strategist with many options of action and choices of behavior and social partners.

Animals↗
PubMed1982

Interactions in connective tissues involving monocyte/macrophages and control of production of proteinases and proteinase inhibitors.

Using human articular chondrocytes in monolayer culture as an experimental system, we have been studying mechanisms of control of production and activity of neutral proteases which degrade connective tissue matrices. Soluble factors from cultured human blood mononuclear cells (MCF) or synovial fragment cultures (SF) stimulate the production of collagenase and proteoglycanase by chondrocytes. Chondrocytes also release a collagenase inhibitor (mol. wt. 26-31,000), which is similar to the tissue inhibitor of metalloproteinases (TIMP) synthesized by cultured mammalian tissues and this is reduced in cultures exposed to MCF or SF. Retinol and dexamethasone partially inhibit the factor-stimulated collagenase, but increase the amount of inhibitor, restoring it to control levels in the presence of MCF or SF. The effects of these agents in cellular interactions in vitro will be discussed in relation to their possible roles in the control of connective tissue turnover in vivo.

Blood Proteins↗
PubMed1981

Metalloproteinases from rabbit bone culture medium degrade types IV and V collagens, laminin and fibronectin.

Gel-filtration chromatography of culture medium from rabbit bone explants separates three latent metalloproteinases with activities against collagen, proteoglycan and gelatin respectively. The fractions degrading proteoglycan also degrade laminin, fibronectin and the polymeric products of pepsin-solubilized type IV collagen and can also solubilize insoluble type IV collagen. The fractions degrading gelatin are capable of degrading solubilized type V and 1 alpha,2 alpha,3 alpha (cartilage) collagens, as well as the lower-molecular-weight products of pepsin-solubilized type IV collagen. All activities can be inhibited by 1,10-phenanthroline and occur in either partially or totally latent forms that can be activated by 4-aminophenylmercuric acetate.

Animals↗
PubMed1981

Purification of rabbit bone inhibitor of collagenase.

1. Rabbit bones in tissue culture synthesize an inhibitor of collagenase during the first 4 days of culture. 2. The inhibitor was purified by a combination of gel filtration, concanavalin A--Sepharose chromatography, ion-exchange chromatography and zinc-chelate affinity chromatography. 3. The purified inhibitor migrated as a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and had a mol.wt. of 28000. 4. The inhibitor blocked the activity of the metalloproteinases collagenase, gelatinase, neutral proteinase III (proteoglycanase), human leucocyte collagenase and gelatinase, but not thermolysin or bacterial collagenase. The serine proteinases plasmin and trypsin were not inhibited. 5. The inhibitor interacted with purified rabbit bone collagenase with 1:1 stoichiometry. 6. The inhibitory activity was lost after incubation for 1 h at 90 degrees C, after treatment with trypsin (250 micrograms/ml) at 37 degrees C for 30 min and after reduction and alkylation.

Animals↗
PubMed1981

An inhibitor of collagenase from human amniotic fluid. Purification, characterization and action on metalloproteinases.

1. An inhibitor of collagenase of apparent mol.wt. 28000 was isolated from term human amniotic fluid. 2. It is active against mammalian collagenases from a number of species and tissues as well as other mammalian metalloproteinases, but has no activity against bacterial metalloproteinases. 3. Activity is destroyed by treatment with either trypsin or 4-aminophenylmercuric acetate, by heat, and by reduction and carboxymethylation. 4. All the properties observed suggest that it is similar to the synthesized tissue inhibitor of metalloproteinases.

Aminophenols↗
PubMed1981

The effects of dexamethasone in vitro on the production of collagenase and inhibitor by synovial and cartilage explants from the joints of rabbits with a proliferative arthritis.

Using a rabbit model arthritis we have investigated the ability of dexamethasone to alter the production of collagenase and the specific metallo-proteinase inhibitor TIMP by explants of synovium and cartilage in vitro. The patterns of collagenase and TIMP production by untreated explants from arthritic joint tissues in culture were similar to those described previously [1, 2]. Dexamethasone dramatically altered the patterns of production of collagenase and TIMP. At a dose of 10 nM, or above, the patterns of production by treated synovium resembled those of normal rabbit synovium: collagenase production was suppressed and TIMP increased compared with untreated arthritic synovium. The levels of latent collagenase in cartilage also fell with increasing doses of dexamethasone and TIMP levels were higher, although normal levels were not reached. These experiments have been conducted as a prelude to testing the effects of various anti-rheumatic drugs in vivo, and attempting to correlate changes in clinical parameters with the subsequent production of collagenase and TIMP in vitro. The data are discussed in relation to the therapeutic use of corticosteroids and to their mode of action on joint tissues.

Animals↗
PubMed1981

The production in culture of metalloproteinases and an inhibitor by joint tissues from normal rabbits, and from rabbits with a model arthritis. I. Synovium.

During 5 days of culture, explants of normal rabbit synovium produced no active collagenase, negligible latent collagenase, but significant levels of free collagenase inhibitor. Synovium from joints exhibiting a proliferative arthritis produced greatly elevated levels of collagenase; the appearance of active enzyme in the medium during the second day of culture was associated with the disappearance of free inhibitor. Enzyme levels in the media correlated well with the arthritic status of joints, when explants were prepared up to 10 weeks after the induction of the model arthritis. Synovium from the contralateral joints of rabbits with unilaterally induced arthritis produced no active collagenase, but approximately one-third as much latent collagenase as found with arthritic joints. Enzymatic activities against gelatin and cartilage proteoglycan substrates were demonstrated in synovial culture media in addition to collagenolytic activity. Gel filtration showed that these activities were not due to a single enzyme, and further characterisation confirmed that the enzymes were metalloproteinases. The results are considered in the light of published data, and the involvement of metalloproteinases and their specific inhibitor in the development of arthritic lesions is discussed.

Animals↗
PubMed1981

The production in culture of metalloproteinases and an inhibitor by joint tissues from normal rabbits, and from rabbits with a model arthritis. II. Articular cartilage.

During the development of proliferative arthritis in the knee joints of rabbits, there was a large increase in the ability of articular cartilage explants to produce latent collagenase in culture. In parallel, the normally high levels of collagenase inhibitor produced by cartilage in culture fell, but active collagenase was never detectable. Characterisation of the collagenase and other proteinase activities produced by rabbit articular cartilage in culture showed that two activities could be separated by gel filtration, one with activities on gelatin and cartilage proteoglycan and the other degrading collage. Under the conditions employed in this paper no resolution of the gelatin and proteoglycan activities could be achieved. All the activities were in a latent form, activated by 4-aminophenylmercuric acetate (APMA), and inhibited by 1,10-phenanthroline or EDTA, but not by di-isopropylfluorophosphate (DFP), indicating that they are metalloproteinases. Characterization of the collagenase inhibitor showed a single peak of activity of apparent molecular weight of 28,000 on gel filtration. The inhibitor was sensitive to APMA and also inhibited other rabbit metalloproteinases, analogous to the system described for rabbit bone. The physiological significance of the synthesis by articular cartilage of proteinases that destroy connective tissue macromolecules and the presence of an enzyme-inhibitor control system is discussed.

Animals↗
PubMed1981

Estramustine phosphate with multiple cytotoxic agents in treatment of advanced prostatic cancer.

Twenty-five patients with histologically proved adenocarcinoma of the prostate were divided into two groups and submitted to combination therapy with estramustine (Estracyt), cyclophosphamide (Cytoxan), 5-fluorouracil, and Cisplatin. Group A consisted of 10 patients newly diagnosed Stage D disease with no prior treatment. Group B consisted of 15 Stage D patients who had become hormonally unresponsive. Group A patients demonstrated an initial 100 per cent response rate including 70 per cent partial objective responses and 30 per cent stabilizations. Group B patients had a 46 per cent response with 39 per cent complete and partial responses and 6 per cent as stabilized. Toxicity was tolerable judged by the NPCP criteria. Both groups of patients are still under study for up to two years to determine if this therapy is superior to other traditional therapies.

Adenocarcinoma↗
PubMed1981

Production of collagenase and inhibitor (TIMP) by normal, rheumatoid and osteoarthritic synovium in vitro: effects of hydrocortisone and indomethacin.

1. The amounts of latent and active collagenase and of collagenase inhibitor (TIMP) produced by two normal, three rheumatoid and two osteoarthritic synovial specimens in culture were compared. Normal synovia produced TIMP, but little latent enzyme. Rheumatoid synovia produced higher levels of total collagenase activity than normal, of which up to 50% in one sample was present in the medium in an active form, whereas no specific inhibitory activity due to TIMP was detectable. The amounts of collagenase and TIMP produced by osteoarthritic synovia were more variable and appeared to reflect the degree of inflammation in the tissue at the time of initiating the cultures. 2. Concentrations of TIMP were usually higher in the culture media of normal, rheumatoid and osteoarthritic synovia when hydrocortisone was present. Correspondingly, amounts of total collagenase were reduced. Production of prostaglandin E (PGE) were inhibited in a dose-dependent manner by hydrocortisone. 3. Indomethacin had no consistent effect on the production of TIMP by rheumatoid and osteoarthritic synovia, although it tended to depress production of collagenase. The production of TIMP by normal synovia was depressed by indomethacin. No PGE was detectable in the media when indomethacin was present. 4. These results are consistent with those from previous animal studies, and we conclude that the balance between production of collagenase and TIMP may be critical in determining the extent of the destructive processes in arthritis. The ability of hydrocortisone to suppress production of collagenase and to increase free TIMP concentration, as well as to inhibit synthesis of prostaglandin, may explain in part how the drug exerts its therapeutic effects in patients with rheumatoid arthritis.

Cells, Cultured↗
PubMed1981

Characterization of collagenase, other metallo-proteinases and an inhibitor (TIMP) produced by human synovium and cartilage in culture.

1. Explants of human synovium from normal, rheumatoid and osteoarthritic subjects produced proteinases in culture that could degrade connective tissue macromolecules at neutral pH. 2. The proteinases detected in the media were predominantly of the class requiring metal ions for activity, and occurred in either partially or wholly latent forms. Activation could be achieved by treatment with either trypsin or the organo-mercurial, 4-aminophenylmercuric acetate. 3. Explants of both normal and osteoarthritic synovium produced an inhibitor of collagenase in the early days of culture, similar to that previously described for rabbit tissues. In contrast, no free inhibitor could be detected in the media of rheumatoid synovial cultures. 4. Explants of normal human articular cartilage produced latent collagenase and free inhibitor in culture. 5. These findings suggest that the activity of tissue-derived metallo-proteinases may be controlled by locally synthesized inhibitors, by mechanisms analogous to those already described for rabbit model systems. Changes in the synthesis and degradation of inhibitor could be important in human diseases in which destruction of connective tissue is a prominent feature.

Cartilage↗
PubMed1980

The latent collagenase and gelatinase of human polymorphonuclear neutrophil leucocytes.

Two metallo-proteinases of human neutrophil leucocytes, collagenase and gelatinase, were studied. Collagenase specifically cleaved native collagen into the TCA and TCB fragments, whereas gelatinase degraded denatured collagen, i.e. gelatin, and the TCA fragments produced by collagenase. On subcellular fractionation by zonal sedimentation, collagenase was found to be localized in the specific granules, separate from gelatinase, which was recovered in smaller subcellular organelles known as C-particles. Neither enzyme was present in the azurophil granules, which contain the two major serine proteinases of neutrophils, elastase and cathepsin G. Collagenase and gelatinase were separated by gel filtration from extracts of partially purified granules. Both enzymes were found to occur in latent forms and were activated either by trypsin or by 4-aminophenylmercuric acetate. Gelatinase was also activated by cathepsin G, which, however, destroyed collagenase. Both enzymes were destroyed by neutrophil elastase. Activation resulted in a decrease by 25 000 in the apparent mol. wt. of both latent metallo-proteinases.

Collagen↗