The effects of TIMP-1 and -2 on canine chondrocytes cultured in three-dimensional agarose culture system

OBJECTIVE: To investigate the effects of tissue inhibitor of metalloproteinase (TIMP)-1 and -2 on chondrocytes cultured with or without interleukin (IL)-1 beta. DESIGN: Canine articular chondrocytes were cultured in three-dimensional (3-D) agarose constructs. Cells were distributed into each of the two groups, those without IL-1 beta and those with IL-1 beta added to the liquid media. Each group was subdivided into three groups, based on the presence of TIMP-1 or -2. IL-1 beta and TIMPs were added to liquid media bathing the 3-D constructs beginning on day 3. The liquid media and the 3-D constructs were collected on days 9, 15, and 24, and analyzed histologically, biochemically, and immunohistochemically. RESULTS: Addition of TIMP-1 or -2 resulted in decreases in matrix metalloproteinase (MMP)-3 concentrations of 37 and 41%, and MMP-1 immunoreactivity of 32 and 36%, respectively, compared with the IL-1 beta group, on day 9. Chondrocytes in groups without IL-1 beta maintained viability and produced abundant extracellular matrix (ECM). Chondrocytes in IL-1 beta groups appeared less viable and produced less ECM compared with those without IL-1 beta. Glycosaminoglycan (GAG) concentrations in 3-D constructs (GAG/weight) were significantly (P<0.001) higher in groups without IL-1 beta than in those with IL-1 beta, on days 15 and 24. CONCLUSIONS: The addition of TIMP was not detrimental to chondrocytes, as used in this study. Despite evidence of decreased MMP levels, TIMPs did not prevent IL-1 beta-associated changes in cellular or ECM characteristics. Further study is necessary before clinically relevant conclusions can be drawn regarding the use of TIMPs in the treatment of osteoarthritis.     

Weight management and current options in pharmacotherapy: orlistat and sibutramine

BACKGROUND: Chronic obesity is associated with various cardiovascular disorders, including diabetes, dyslipidemia, and hypertension. Pharmacotherapy with antiobesity agents is an important management strategy in conjunction with lifestyle interventions. OBJECTIVE: This article describes the pharmacologic management of obesity, concentrating on orlistat and sibutramine. METHODS: Relevant articles were identified through a MEDLINE search (1966-February 2002) using the terms obesity, overweight, weight loss, antiobesity drugs, orlistat, and sibutramine. The search for efficacy trials was limited to randomized controlled studies of >6 months' duration. Also included in the review were relevant references cited in the bibliographies of identified articles, news reports, and the authors' own data. RESULTS: Orlistat reduces fat absorption by inhibiting gastrointestinal lipases. In randomized, controlled trials of up to 2 years' duration, orlistat plus a hypocaloric diet produced significantly greater weight loss than placebo (P < 0.001). In the maintenance phase, patients taking orlistat had less weight regain than did placebo recipients. The weight reduction with orlistat was also associated with a significant improvement in control of cardiovascular risk factors (P < 0.05). Unlike orlistat, sibutramine works by suppressing appetite; its efficacy, however, was similar to that of orlistat in the identified clinical trials. Orlistat was associated primarily with gastrointestinal side effects. Use of orlistat was associated with minimal drug interactions, except with cyclosporine, with which it should not be taken. Sibutramine was also well tolerated, although it may cause dry mouth, anorexia, and insomnia, and should be used with caution in patients at risk for cardiovascular disease. CONCLUSIONS: Orlistat and sibutramine demonstrated a favorable efficacy and safety profile in randomized controlled trials. Current evidence supports their use as adjuncts to lifestyle modifications in the treatment of obesity.     

Treating hypertension in diabetic nephropathy

OBJECTIVE: Control of hypertension in patients with diabetic nephropathy improves mortality and slows progression to end-stage renal disease. However, blood pressure is difficult to treat; multiple drug combination therapy is required and treatment algorithms to establish this are lacking. We used a stepped-care algorithm, centered on maximum doses of an ACE inhibitor or angiotensin II receptor blocker, to treat hypertension according to American Diabetes Association recommended blood pressure target goals (<130/80 mmHg) in patients with diabetic nephropathy. RESEARCH DESIGN AND METHODS: We treated 49 consecutive patients with diabetes (13 with type 1 and 36 with type 2), diabetic nephropathy, and proteinuria > or =500 mg/24 h with a stepped-care blood pressure treatment algorithm. The level of blood pressure control achieved at most recent follow-up was assessed. RESULTS: Patients were followed for a median of 18 months (range 9-48). Mean blood pressure achieved was 140/75 +/- 23/14 mmHg in patients with type 1 diabetes and 146/76 +/- 22/14 mmHg in patients with type 2 diabetes. Target blood pressure was reached in 16 (33%) patients, 6 of 13 patients with type 1 diabetes and 10 of 36 patients with type 2 diabetes, whereas systolic blood pressure remained above the target level in the remaining patients. There was no difference in baseline blood pressure, proteinuria, or serum creatinine level between patients who were treated to target and those who were not. CONCLUSIONS: Levels of blood pressure control similar to those achieved in clinical trials in diabetic nephropathy were obtained with a stepped-care algorithm. However, in most patients, systolic blood pressure was difficult to control to target despite the use of multiple drug combination therapy.     

Anterior corneal optical aberrations induced by photorefractive keratectomy for hyperopia

PURPOSE: Photorefractive keratectomy (PRK) for hyperopia requires both a steepening of the central cornea and a flattening of the mid-periphery to achieve its effect and is likely to affect the optical aberrations of the eye. METHODS: Nine patients underwent PRK to correct between +2.00 and +4.00 D of hyperopia (first eye treated for each patient) using the Summit Technology Apex Plus excimer laser. Anterior corneal aberrations for pupil diameters of 3, 5.5 and 7 mm were estimated from corneal topography data (TMS-1), assuming a uni-index, single surface cornea. Refractive error was assessed using retinoscopy and standard subjective tests. RESULTS: Apart from the intended change in refraction (mean spherical equivalent manifest refraction, +4.60 +/- 1.60 D before surgery and +0.70 +/- 1.60 D at 1 year after surgery), the most significant change was in spherical aberration. Anterior corneal spherical aberration was positive (+1.60 +/- 0.60 D for a 5.5-mm pupil) before surgery and became negative after surgery (-1.80 +/- 1.20 D at 1 year). The change in spherical aberration was related to the achieved change in refractive error. CONCLUSIONS: The large change (approximately 3.00 D) in spherical aberration (from positive to negative aberration) has implications for the optical performance of the whole eye, where the effects of lenticular aberration must also be considered.     

The C6-2B glioma cell P2Y(AC) receptor is pharmacologically and molecularly identical to the platelet P2Y(12) receptor

P2Y receptor activation in many cell types leads to phospholipase C activation and accumulation of inositol phosphates, while in blood platelets, C6-2B glioma cells, and in B10 microvascular endothelial cells a P2Y receptor subtype, which couples to inhibition of adenylyl cyclase, historically termed P2Y(AC), (P2T(AC) or P(2T) in platelets) has been identified. Recently, this receptor has been cloned and designated P2Y(12) in keeping with current P2 receptor nomenclature. Three selective P(2T) receptor antagonists, with a range of affinities, inhibited ADP-induced aggregation of washed human or rat platelets, in a concentration-dependent manner, with a rank order of antagonist potency (pIC(50), human: rat) of AR-C78511 (8.5 : 9.1)>AR-C69581 (6.2 : 6.0)>AR-C70300 (5.4 : 5.1). However, these compounds had no effect on ADP-induced platelet shape change. All three antagonists had no significant effect on the ADP-induced inositol phosphate formation in 1321N1 astrocytoma cells stably expressing the P2Y(1) receptor, when used at concentrations that inhibit platelet aggregation. These antagonists also blocked ADP-induced inhibition of adenylyl cyclase in rat platelets and C6-2B cells with identical rank orders of potency and overlapping concentration - response curves. RT - PCR and nucleotide sequence analyses revealed that the C6-2B cells express the P2Y(12) mRNA. These data demonstrate that the P2Y(AC) receptor in C6-2B cells is pharmacologically identical to the P2T(AC) receptor in rat platelets.     

CDX2 mutations do not account for juvenile polyposis or Peutz-Jeghers syndrome and occur infrequently in sporadic colorectal cancers

Peutz-Jeghers syndrome (PJS) and juvenile polyposis (JPS) are both characterized by the presence of hamartomatous polyps and increased risk of malignancy in the gastrointestinal tract. Mutations of the LKB1 and SMAD4 genes have been shown recently to cause a number of PJS and JPS cases respectively, but there remains considerable uncharacterized genetic heterogeneity in these syndromes, particularly JPS. The mouse homologue of CDX2 has been shown to give rise to a phenotype which includes hamartomatous-like polyps in the colon and is therefore a good candidate for JPS and PJS cases which are not accounted for by the SMAD4 and LKB1 genes. By analogy with SMAD4, CDX2 is also a candidate for somatic mutation in sporadic colorectal cancer. We have screened 37 JPS families/cases without known SMAD4 mutations, 10 Peutz-Jeghers cases without known LKB1 mutations and 49 sporadic colorectal cancers for mutations in CDX2. Although polymorphic variants and rare variants of unlikely significance were detected, no pathogenic CDX2 mutations were found in any case of JPS or PJS, or in any of the sporadic cancers.     

Nerve growth factor modulates the activation status and fast axonal transport of ERK 1/2 in adult nociceptive neurones

Mature dorsal root ganglion cells respond to neurotrophins, and the intracellular signalling pathways activated by neurotrophins have been characterized in vitro. We have now used immunocytochemistry and Western blots to examine the expression and activation of extracellular signal-regulated protein kinase-1/2 (ERK) in rat dorsal root ganglion cells in vivo, using antisera to total (tERK) and phosphorylated (pERK) forms. This has revealed a number of novel findings. tERK immunoreactivity is present in most dorsal root ganglion cells but is expressed most strongly in small (nociceptive) cells and, surprisingly, is absent in a population of large cells that expressed trkB or trkC but mainly lack p75(NTR) immunoreactivity. In contrast pERK is prominent in a few trkA cells and in satellite glial cells, and is further increased by NGF treatment. tERK and pERK both undergo fast anterograde and retrograde axonal transport, indicated by accumulation at a sciatic nerve ligature, and NGF reduces the level of retrograde pERK transport.     

The coastal environment and human health: microbial indicators,pathogens, sentinels and reservoirs

Innovative research relating oceans and human health is advancing our understanding of disease-causing organisms in coastal ecosystems. Novel techniques are elucidating the loading, transport and fate of pathogens in coastal ecosystems, and identifying sources of contamination. This research is facilitating improved risk assessments for seafood consumers and those who use the oceans for recreation. A number of challenges still remain and define future directions of research and public policy. Sample processing and molecular detection techniques need to be advanced to allow rapid and specific identification of microbes of public health concern from complex environmental samples. Water quality standards need to be updated to more accurately reflect health risks and to provide managers with improved tools for decision-making. Greater discrimination of virulent versus harmless microbes is needed to identify environmental reservoirs of pathogens and factors leading to human infections. Investigations must include examination of microbial community dynamics that may be important from a human health perspective. Further research is needed to evaluate the ecology of non-enteric water-transmitted diseases. Sentinels should also be established and monitored, providing early warning of dangers to ecosystem health. Taken together, this effort will provide more reliable information about public health risks associated with beaches and seafood consumption, and how human activities can affect their exposure to disease-causing organisms from the oceans.     

Apparent Mendelian inheritance of breast and colorectal cancer: chance, genetic heterogeneity or a new gene?

It is not uncommon for cancer geneticists to be referred families with apparently Mendelian co-inheritance of breast and bowel cancer. Such families present a particular problem as regards the intensity of their screening for these diseases and the utility of genetic testing. Many 'breast-colon' cancer families probably result from chance clustering of two common cancers. Other 'breast-colon' cancer families may result from known cancer syndromes, such as hereditary breast-ovarian cancer or hereditary non-polyposis colon cancer, either by conferring a high risk of one cancer type and a slightly increased risk of the other, or through a predisposition to one of the two cancers and chance occurrence of the other. Anecdotally, however, many geneticists wonder about the existence of a distinct 'breast-colon cancer syndrome', since some families present good a priori evidence of genetic disease and yet cannot readily be accounted for by known genes or chance. The identification of unknown 'breast-colon cancer' genes is likely to be difficult, relying primarily on candidate gene analysis, including loci separately implicated in breast or colorectal cancer, or in other multiple cancer syndromes. Studies such as those on APC I1307K and CHEK2 1100delC may suggest the way forward for the identification of 'breast-colon cancer' genes.