Biomedical subjects
Publications and source records attributed to G Murphy.
The value of the Radial Head-Capitellum view has been assessed in a series of 28 consecutive cases of radial head fracture. Additional useful information was obtained in 21% of cases. The Radial Head-Capitellum view may be a valuable additional view in assessing radial head trauma.
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Inhibitors of the mammalian metalloproteinases, collagenase, proteoglycanase and gelatinase were isolated from bovine cartilage (extracts and culture medium) and bovine amniotic fluid and serum. These inhibitors either bind or do not bind to concanavalin-A--Sepharose, with Mr (gel filtration) of about 30 000 and 20 000, respectively. Cartilage and chondrocyte culture media contained only concanavalin-A-binding inhibitors whereas cartilage extracts contained only a non-binding inhibitor: serum and amniotic fluid contained both forms of inhibitory activities. In moist biochemical respects, particularly in their abilities to inhibit metalloproteinases, all of the inhibitors were found to be similar. It is concluded that the forms of the inhibitors that differ in Mr may be closely related to the tissue inhibitor of metalloproteinases (TIMP) previously purified from rabbit and human sources. These findings help to clarify other studies on collagenase inhibitors and support the concept that TIMP-like inhibitors may be important in the control of connective tissue degradation.
Two rapid, sensitive, and specific gas chromatographic (GC) methods for the quantitative determination of quazepam (I), 7-chloro-5-(2-fluorophenyl-1,3-dihydro-1-(2,2,2-trifluoroethyl) -2H-1,4-benzodiazepine-2-thione, and its major active plasma metabolites, the 2-oxo compound (II) and the dealkylated oxo compound (III), have been developed; the first measures I and II and the second measures III. The compounds are extracted from plasma with toluene and quantitated by electron-capture detection using the internal standard method. The methods are capable of quantitating plasma levels of I and II as low as 0.75 ng/mL and plasma levels of III as low as 1.5 ng/mL. Correlation coefficients of standard curves were greater than 0.9995 for all compounds. Precision of the methods was measured at two different concentrations for each compound; the CV values were 3-6% for all three compounds. The recovery of all compounds was greater than 80%, and the ratio of recovery of each compound to that of its internal standard did not vary at different concentrations, indicating appropriate internal standards have been selected for the methods. Quazepam metabolites, other benzodiazepines, and drugs which are potential comedication do not interfere with either method. The methods were shown to be suitable for investigating the bioavailability and pharmacokinetics of quazepam at therapeutic doses.
Cricothyroidotomy for long-term tracheal access was prospectively studied in 76 critically ill patients. Thirty patients (39%) survived and 46 (61%) died. Mean duration of follow-up computed in all survivors was 8.5 months. Postmortem examination of the airway was performed in 85% of the nonsurvivors. Five patients (7%) had major complications including one death, subglottic stenosis in two adolescent patients, reversible subglottic granulation with partial obstruction in one patient, and tracheomalacia in one patient. Minor complications occurred in 23 (30%) survivors. Eleven (28%) of the nonsurvivors examined post mortem had airway pathology, including ulceration, hemorrhage and abscess at the stoma or cuff site, subglottic erosion, and mucosal separation. There were no significant differences in any of the parameters studied between the group with and the group without airway pathology. The morbidity and mortality of cricothyroidotomy in adults are similar to that reported for tracheostomy. However, cricothyroidotomy should be avoided in children and adolescents because of the risk of subglottic stenosis.
The Wagner external skeletal-fixation system was used to treat twenty complex fractures involving the femur, and nineteen of the fractures healed. Chronic osteomyelitis did not develop in any of the patients.
Human articular chondrocytes in culture produced large amounts of specific mammalian collagenase, gelatinase and proteoglycanase when exposed to dialysed supernatant medium derived from cultured human blood mononuclear cells (mononuclear cell factor) or to conditioned medium, partially purified by fractionation with ammonium sulphate (60-90% fraction), from cultures of human synovial tissue (synovial factor). Human chondrocytes and synovial cells also released into culture medium an inhibitor of collagenase of apparent molecular weight about 30 000, which appeared to be similar to the tissue inhibitor of metalloproteinases synthesised by tissues in culture. The amounts of free collagenase inhibitor were reduced in culture media from chondrocytes or synovial cells exposed to mononuclear cell factor or synovial factor. While retinol inhibited the production of collagenase brought about by mononuclear cell factor or synovial factor, it restored the levels of inhibitor, which were reduced in the presence of mononuclear cell factor or synovial factor. Dexamethasone markedly reduced the production of collagenase by synovial cells, while only partially inhibiting factor-stimulated collagenase production by chondrocytes. Addition of puromycin as an inhibitor of protein synthesis reduced the amounts of both collagenase and inhibitor to control or undetectable levels.
1. Pure rabbit bone metalloproteinase inhibitor (TIMP) bound tightly to pure rabbit bone collagenase with an apparent Kd of 1.4 X 10(-10) M. 2. The molecular weight of the enzyme-inhibitor complex was found to be 54 000, but no enzyme activity could be recovered from the complex after treatment with either mercurials or proteinases. The complex thus differed from latent collagenase in terms of size, susceptibility to mercurials and behaviour on concanavalin A-Sepharose. 3. The interaction of the purified components was compared with that of crude collagenase and crude inhibitor in culture medium. Mercurial treatment partially reversed the inhibition in the crude system, but not when the purified components were used. 4. The significance of the results is discussed in relation to the extracellular control of the activity of collagenase.
A metalloproteinase, 'proteoglycanase', that degrades proteoglycan and insoluble type IV collagen as well as casein was purified to homogeneity from rabbit bone culture medium. The major form of this proteinase had a final specific activity of 2400 micrograms of casein degraded/min per mg of enzyme protein, and Mr 24 500 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis or 12 500 by gel-filtration chromatography. It was active over the pH range 5.0-9.0 against a number of substrates, and the rates of degradation were almost constant over the whole of this range. The products generated from proteoglycan-aggregate degradation by this enzyme indicated cleavage at multiple chondroitin sulphate-binding sites along the protein core. In a new assay to detect degradation of insoluble type IV collagen, the proteoglycanase generated large fragments, probably by cleavage in the non-helical regions. The enzyme degraded laminin, fibronectin and procollagen, removing the extension peptides of the last-mentioned. It also cleaved the 'weak region' of the type III collagen helix in a manner analogous to trypsin. The synthetic substrate 2,4-dinitrophenyl-Pro-Leu-Gly-Ile-Ala-Gly-Arg-NH2 was cleaved exclusively at the Gly-Ile bond. The proteoglycanase was inhibited by tissue inhibitors of metalloproteinases from rabbit bone culture medium, human amniotic fluid and bovine nasal-cartilage extracts, forming essentially irreversible inactive complexes. The importance of this tissue-derived enzyme, with such a wide-ranging degradative capacity, in normal and pathological connective-tissue matrix degradation is discussed.
It has long been recognised that there is a relationship between emotional stress and some forms of infertility. We have endeavoured to estimate "stress' levels before and after Autogenic Training in 15 couples with infertility of at least two years' duration. Potential stress markers were: plasma prolactin, total urinary free cortisol and catecholamines, and four psychological tests: Spielberger State-Trait anxiety scale, Taylor Manifest Anxiety Scale, the Cattell 16 personality factor questionnaire, and the Eysenck Personality Questionnaire. A control group of ten normal couples was included for comparison. The biochemical finding of higher mean prolactin levels in the female patients vs their controls was of particular interest. The significant reduction of the prolactin level, in parallel with decreased anxiety scores following treatment, supports the hypothesis that the elevated prolactin levels in these patients are indeed linked with emotional stress.
We present an analysis of observational data on the behavior profiles for two groups of infant langur monkeys (Presbytis entellus): one that had experienced mother loss, and the other, a control group, that had not undergone mother loss. Observations were analyzed in three 2-week time periods: 2 preseparation, 2 separation, and 2 postseparation periods for both groups. The profile analysis application of the multivariate analysis of variance (MANOVA) was employed to test the hypothesis that the two groups had similar patterns of change across time. For each group a vector of 5 difference scores was computed; then MANOVA was used to test the similarity of the mean vectors of difference scores for the two groups. Profiles for the separation and control infants were significantly different for some behaviors, and changes between some time periods were also significant.
Collagenase secretion was studied on cultures of rabbit articular chondrocytes. Differentiation of the cells was assessed by characterizing the type of 3H-labelled collagen produced during treatment with (1) conditioned media from rabbit peritoneal macrophages and human blood mononuclear cells, and (2) with retinol, a potent cartilage resorbing agent in tissue culture. Conditioned media stimulated collagenase secretion. Total collagen synthesis was reduced due to a decrease of synthesis of alpha 1 chains; the amount of alpha 2 chains synthesized was unchanged. This is thought to be due to a reduction in type II synthesis. Retinol did not stimulate collagenase secretion. Total collagen synthesis was reduced by retinol. alpha 2 chain synthesis, however, was significantly increased, suggesting a switch of collagen synthesis in favor of type I collagen, and therefore, dedifferentiation. These results demonstrate that dedifferentiation of chondrocytes with respect to collagen synthesis is not necessarily associated with a stimulation of collagenase secretion.
The separation and further purification of human polymorphonuclear-leucocyte collagenase and gelatinase, using modifications of the method of Cawston & Tyler [(1979) Biochem J. 183, 647-656], are described. The final preparations yielded collagenase of specific activity 260 units/mg and gelatinase of specific activity 13 000 units/mg. Gelatinase was purified to apparent homogeneity in a latent form, and analysis of the activation of 125I-labelled latent enzyme by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel-filtration techniques suggested that no peptide material was lost on conversion into the active form. The purified natural inhibitors alpha 2-macroglobulin, tissue inhibitor of metalloproteinases ('TIMP') and amniotic-fluid inhibitor of metalloproteinases all inhibited the two polymorphonuclear-leucocyte metalloproteinases, but the last two inhibitors were slow to act and complete inhibition was difficult to attain. Collagenase degraded soluble types I and III collagen equally efficiently, but soluble type II collagen less well. Gelatinase alone had little activity on these substrates, although it enhanced the action of collagenase. Gelatinase was capable of degrading soluble types IV and V collagen at 25 degrees C, whereas collagenase was only active at higher temperatures when the collagens were susceptible to trypsin activity. By using tissue preparations of insoluble collagens (type I, II or IV) the activity of leucocyte collagenase was low and gelatinase activity was negligible, as measured by the solubilization of hydroxyproline-containing material. The two enzymes together were two or three times more effective in the degradation of these insoluble collagens.
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Sensory reinforcement was first studied by learning theorists working with animals in the 1950s. Attempts to examine the phenomenon with children followed in the 1960s, and the studies demonstrated that sensory stimuli could act like any other reinforcers with normal young children. Similar work with the autistic and mentally handicapped child arose in relation to both the study of receptor development and more treatment-oriented research. It now seems that even profoundly handicapped children can learn to operate simple levers when reinforced by sensory stimuli, and some handicapped children have learned quite complex skills through sensory reinforcement. There also appears to be a close relationship between stereotyped behavior and sensory reinforcement. The clinical implications of the studies reviewed are discussed.
Destruction of joint structures in arthritis may result from failure of normal mechanisms controlling interactions among cells of the various tissues of the joint. Normal synovium in culture produces less prostaglandin E (PGE) and collagenase than rheumatoid. When rheumatoid synovium is dissociated into cells, the adherent cell cultures rapidly lose the ability to synthesize large amounts of PGE and collagenase and become indistinguishable from normal synovial cells. A mononuclear cell factor (MCF) derived from supernatant media of cultured human blood mononuclear cells and a 'synovial factor(s)' (SF) from cultures of either normal or rheumatoid synovial fragments both stimulate production of PGE and proteinase by cells derived from human synovium, cartilage and bone. The activities of factors which may be present in these stimulatory supernatants may be unmasked in vitro when they are removed from the normal control present in vivo. Normal synovium probably contains cells which, with the appropriate stimulus, may be recruited to participate in joint tissue degradation. Normal connective tissue turnover may also be controlled by a neutral metallo-proteinase inhibitor (TIMP), which is produced in considerable amounts by normal synovium, but which cannot be detected in cultures of rheumatoid synovium. While corticosteroids inhibit the production and action of MCF and SF, they stimulate production of TIMP by normal or rheumatoid synovial tissue in vitro and may contribute to the endogenous control mechanisms. PGE may also have a modulatory role in these cellular interactions.
Patients with pelvic malignancies often require irradiation as part of the treatment protocol or as definitive treatment for the malignancy. Subsequent urinary diversion with the low lying small bowel or the descending colon often results in increased morbidity. Therefore, a method of urinary diversion using the transverse colon conduit in an end-to-end ureterocolic anastomosis as described by Wallace was used. Several advantages with this method are identifiable easily and are described. The satisfactory results in the last 30 patients who underwent this procedure after pelvic irradiation are presented. The ureterocolic anastomosis with reflux is of particular importance since it allows retrograde conduitograms to be performed at later dates to evaluate the urothelium for possible recurrent disease.
A retrospective review was made of the pretreatment radiographs of 20 patients with well-documented primary lymphoma of bone. Nine radiographic signs were defined, and the presence or absence of each was recorded for each patient. When the radiographic findings were compared with disease-free survival for each patient, it was found that patients who had a relapse had a higher mean number of positive radiographic signs than those who remained disease free (p less than 0.02). Also, those who relapsed early had more positive signs than those who relapsed late (p less than 0.05). Certain signs, i.e., pathologic fracture, layered periosteal new bone, broken periosteal new bone, cortical breakthrough, soft-tissue mass, and soft-tissue swelling, were more helpful than others for making a prognosis. These signs appear to be related to radiologic evidence of imminent or actual soft-tissue extension of the tumor.