Reliability study of the sonographic measurement of the acromiohumeral distance in symptomatic patients.

BACKGROUND: The purpose of this study was to evaluate the inter- and intra-observer reliability and accuracy of sonographic (US) acromiohumeral distance (AHD) measurement for both experienced and novice operators in US in patients suffering from subacromial impingement syndrome. METHOD: A total of 43 patients (50 shoulders) diagnosed with subacromial impingement syndrome were recruited from an orthopedic outpatient clinic. The US measurement of AHD was obtained consecutively in a neutral position and in a 60 degrees abduction position. A total of 300 blinded measurements were taken. RESULT: In the neutral abduction group the intra- observer interclass correlation coefficient (ICC) was 0.94 for the experienced operator and 0.92 for the novice operator. The inter-observer ICC was 0.70 and the accuracy was 1.1 mm. In the 60 degrees abduction group, the intra-observer ICC was 0.90 for the experienced operator and 0.87 for the novice operator. The inter-observer ICC was 0.64 and the accuracy was 1.4 mm. All ICCs were significant at a level of p < 0.0001. CONCLUSION: The inaccuracy of the method was 1 mm regardless of the experience of the observer. US AHD measurement in patients with shoulder complaints is not as accurate as reported in healthy subjects. This may have important implications for the clinical use of this parameter.

Control of the mutagenicity of aromatic amines by protein kinases and phosphatases. I. The protein phosphatase inhibitors okadaic acid and ortho-vanadate drastically reduce the mutagenicity of aromatic amines.

The role of protein kinase C and protein phosphatases was examined in the control of mutagenic metabolites of aromatic amines. Various metabolic activating systems derived from rat liver were treated with: 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C modulator; okadaic acid (OA), a potent inhibitor of serine/threonine protein phosphatases (PP1 and PP2A); and ortho-vanadate (OV), an inhibitor of tyrosine phosphatases. TPA used over a wide concentration range (10(-9)-10(-6) M) did not affect the bacterial mutagenicity of the aromatic amines and of the aromatic amide investigated, 2-aminoanthracene, 2-aminofluorene and 2-acetylaminofluorene (2AAF). At the molecular level, TPA did not affect the function of cytochrome P450s 1A1 or 1A2, which are known key factors for the activation and inactivation of aromatic amines/amides. By contrast the OA and OV treatment of rat hepatocytes, rat liver homogenate, fraction S9 and the nuclear fraction drastically reduced (by > 80%) the mutagenicity of the aromatic amines/amide investigated. This is by far the most pronounced change in genotoxicity observed to date via modulation of phosphorylation. Whilst the mutagenicity of the primary toxication product 2-N-OH-acetylaminofluorene (2-N-OH-AAF) in the presence of exogenous activating systems (hepatocytes, S9-fraction, nuclear fraction) was also reduced by OV, OA had no influence. Thus the tyrosine protein phosphatase inhibitor and the serine/threonine protein phosphatase inhibitor influence the genotoxicity of aromatic amines/amides on different levels. Moreover, this shows that the drastic reduction in mutagenicity by OA was due to its influence on a step prior to the presence of the primary toxication product 2-N-OH-AAF. This reduction could be due to changes in the activity of cytochrome P4501A1 and/or 1A2. However, no incorporation of 32P-labelled phosphate from intracellularly prelabelled [32P]-ATP into cytochromes P450 1A1 or 1A2 nor any change in their catalytic activities was observed in the presence of OA. Furthermore, a phosphorylation dependent change in the function of P-glycoprotein (known for its role in the transport of diverse xenobiotic substances and their metabolites) was shown not to contribute to the observed decrease in mutagenicity. Our results reveal an important role for protein phosphatase 1 and/or 2A and tyrosine phosphatase(s) in the control of the genotoxicity of aromatic amines and amides. However, the present study does not distinguish between effects mediated by individual proteins affected by these protein phosphatases.

[No positive effect of preoperative exercise therapy and teaching in patients to be subjected to hip arthroplasty]. / Geen positief effect van preoperatieve oefentherapie en instructie bij patiënten die heupartroplastiek zullen ondergaan.

OBJECTIVE: To evaluate the benefits of preoperative physical therapy and instruction of patients with primary coxarthrosis to be subjected to a total hip arthroplasty. SETTING: University Hospital Maastricht. DESIGN: Controlled trial. MATERIAL AND METHOD: During 14 months the effects were measured of preoperative physical therapy and instruction of 64 patients divided into two populations; one group (n = 31) received preoperative instruction and physical therapy, the other did not (n = 33). Effects were measured with the Visual Analog Scale, the Harris Hip Score and the days patients could stand, walk, climb a stair and be discharged. RESULTS: The Harris Hip Score showed a significant difference (p < 0.05) favouring the instructed group on day 14 after the operation and at the moment the patients were discharged. The other parameters showed no significant differences between the groups. Differentiation by age, gender and type of arthroplasty showed the same results. CONCLUSION: Preoperative exercise and instruction is not useful for patients who in the near future will be treated with a total hip arthroplasty for primary coxarthrosis.

Molecular and cellular basis for adequate metabolic design of genotoxicity studies.

Genotoxic species and metabolites are usually under the control of a complex set of activating, inactivating and precursor sequestering enzymes. These enzymes differ greatly between test systems, animal species and man. An adequate metabolic design of genotoxicity studies requires careful attention to factors such as: Dilution of cofactors in in vitro tests which are present in much higher concentrations in the intact cell; Induction in high dose carcinogenicity bioassays of enzymes, which are constitutively not expressed and not induced at such doses of the compound, which occur in the situations of the practical use of the compound; Modifications of control enzymes, which are effected by hormones or other endogenous factors, which are differently influenced by high dose (bioassay) versus moderate dose (real exposure) or by in vivo (endocrine regulation) versus in vitro (no endocrine regulation) conditions.

Modulation of the control of mutagenic metabolites derived from cyclophosphamide and ifosfamide by stimulation of protein kinase A.

The phosphorylation of the 2 major phenobarbital-inducible cytochrome P450 isoenzymes IIB1 and IIB2 was increased in intact hepatocytes by the action of the membrane-permeating cAMP derivative N6,O2'-dibutyryl-cAMP. Under these conditions cyclophosphamide and ifosfamide (which are known to be activated by cytochrome P450 IIB1) were investigated for mutagenicity in Salmonella typhimurium TA1535 and TA100 and for cytotoxicity in TA1535. Cyclophosphamide and ifosfamide were transformed to mutagenic and cytotoxic metabolites by the hepatocytes. The activation of both drugs to mutagens was markedly reduced after pretreatment of the hepatocytes with the membrane-permeating cAMP derivative N6,O2'-dibutyryl-cAMP. Cyclophosphamide and ifosfamide activation were reduced to 51% and 38% of unstimulated controls respectively, when hepatocytes were incubated for 1 h with N6,O2'-dibutyryl-cAMP in the presence of the phosphodiesterase inhibitor theophylline, and Salmonella typhimurium TA1535 was used. A marked reduction in mutagenicity of cyclophosphamide (35% compared with unstimulated controls) was also observed under different experimental conditions, namely after pretreatment of the hepatocytes with N6,O2'-dibutyryl-cAMP for 1.5 h without theophylline and using Salmonella typhimurium TA100 as target strain. Continued presence of the cytochrome P450 IIB1 and P450 IIB2 inducer phenobarbital in the stimulation medium increased the mutagenicity of cyclophosphamide and led to an even more marked reduction of mutagenicity by pretreatment of the hepatocytes with N6,O2'-dibutyryl-cAMP and theophylline. In order to investigate whether the observed changes were metabolism-related, the ifosfamide metabolite ifosfamide mustard which does not require metabolic activation by cytochrome P450 was studied under the same conditions. Its mutagenicity was indistinguishable after incubation with N6,O2'-dibutyryl-cAMP-treated or with unstimulated hepatocytes. Also the metabolic formation of cytotoxic metabolites from cyclophosphamide and ifosfamide but not that of ifosfamide mustard was markedly decreased by pretreatment of the hepatocytes with N6,O2'-dibutyryl-cAMP and theophylline. Thus the stimulation of protein kinase A in intact cells has important consequences for the control of genotoxic and cytotoxic metabolites and represents a fast and short-term regulation of it.