Risk factors for tibial tuberosity fracture after tibial tuberosity advancement in dogs.

OBJECTIVE: To retrospectively identify factors that predispose to tibial tuberosity (TT) fracture after tibial tuberosity advancement (TTA) in dogs. METHODS: The medical records and radiographs of a group of control dogs (n = 212) that had TTA surgery (n = 241 procedures) and did not sustain a fracture between 2008 and 2013, and those of 12 dogs that did sustain a fracture (n = 13 procedures) between 2008 and 2013 at two veterinary teaching hospitals were evaluated to determine the effect of signalment, body weight and surgical inaccuracies on TT fracture. Multivariable logistic regression was performed with the occurrence of TT fracture as the outcome variable of interest. RESULTS: Signalment and body weight were not found to be associated with TT fracture. Of the surgical inaccuracies, osteotomy shape (p = 0.003), plate position (p = 0.009), and cage position (p = 0.039) were factors significantly associated with TT fracture. CLINICAL SIGNIFICANCE: This study provides data to support the hypothesis that poor plate position, poor cage position, and narrow distal osteotomy width are associated with TT fracture after TTA. We conclude that it is of paramount importance to pay careful attention to surgical technique in order to reduce this risk.

RGS16 restricts the pro-inflammatory response of monocytes.

Immune cells express powerful and harmful effectors that require tight regulation. Heterotrimeric G proteins are critical mediators in translating extracellular signals into cell responses, which need a fine-tuned regulation for the control of cell activation. Regulator of G-protein signalling 16 (RGS16) has been identified as a key factor of G protein-mediated activation in lymphocytes, modulating inflammatory and survival responses of various cell types. However, data about the expression of this regulatory protein in monocytes are scarce, and it has remained unclear whether activation and migration of these cells are regulated by RGS16. In this study, the impact of RGS16 on the production of inflammatory cytokines by activated human monocytes was investigated in vitro using the human promonocytic cell line THP-1 as a model. Gain and loss of function experiments showed that RGS16 overexpression reduces the expression of pro-inflammatory cytokines IL-1ß, IL-6, IL-8 and TNFα, while RGS16 knockdown by RNAi upregulates IL-1ß, IL-6 and TNFα but not IL-8. RGS16 knockdown was also shown to enhance Pam3-mediated induction of the anti-inflammatory cytokine IL-10. Our results indicate that RGS16 restricts the activation-induced pro-inflammatory profile in myeloid cells.

Acid hydrolysis of bacterial cellulose reveals different modes of synergistic action between cellobiohydrolase I and endoglucanase I.

Intact and partially acid hydrolyzed cellulose from Acetobacter xylinum were used as model substrates for cellulose hydrolysis by 1,4-beta-D-glucan-cellobiohydrolase I (CBH I) and 1,4-beta-D-endoglucanase I (EG I) from Trichoderma reesei. A high synergy between CBH I and EG I in simultaneous action was observed with intact bacterial cellulose (BC), but this synergistic effect was rapidly reduced by acid pretreatment of the cellulose. Moreover, a distinct synergistic effect was observed upon sequential endo-exo action on BC, but not on bacterial microcrystalline cellulose (BMCC). A mechanism for endo-exo synergism on crystalline cellulose is proposed where the simultaneous action of the enzymes counteract the decrease of activity caused by undesirable changes in the cellulose surface microstructure.

Gastrointestinal and hepatic manifestations of human ehrlichiosis: 8 cases and a review of the literature.

BACKGROUND: Ehrlichiosis has emerged as an increasingly recognized tick-borne rickettsial disease. It can affect multiple organs including the gastrointestinal tract and liver. Signs and symptoms include abdominal pain, nausea, vomiting, diarrhea, jaundice, and hepatosplenomegaly. Patients commonly have elevated liver transaminases early in the course of illness as well as leukopenia and thrombocytopenia. If not diagnosed and treated in a timely fashion, ehrlichiosis can progress to multiorgan failure. METHODS: Between 1992 and 1998, 8 patients meeting the CDC criteria for ehrlichiosis were diagnosed and treated at the John L. McClellan Memorial Veterans Hospital and University Hospital in Little Rock, Ark. These cases and English-language articles relating to gastrointestinal and hepatic manifestations of ehrlichiosis, identified by searching Medline and manually reviewing bibliographies of retrieved articles, are reviewed. RESULTS: Seven of the eight patients had elevated transaminases on presentation which increased rapidly initially and slowly returned to normal. Three of our patients had hyperbilirubinemia. One of the eight patients presented with hepatomegaly. Three had hyperbilirubinemia with a peak bilirubin of 13.8 mg/dl. Two patients (25%) had a rash on presentation. All 8 patients were treated with and responded to doxycycline. One developed multiorgan failure but eventually recovered with intensive medical care and doxycycline. CONCLUSION: To avoid treatment delay and serious complications, in the appropriate clinical setting ehrlichiosis should be considered as a cause of elevated liver transaminases.

Endoglucanase 28 (Cel12A), a new Phanerochaete chrysosporium cellulase.

A 28-kDa endoglucanase was isolated from the culture filtrate of Phanerochaete chrysosporium strain K3 and named EG 28. It degrades carboxymethylated cellulose and amorphous cellulose, and to a lesser degree xylan and mannan but not microcrystalline cellulose (Avicel). EG 28 is unusual among cellulases from aerobic fungi, in that it appears to lack a cellulose-binding domain and does not bind to crystalline cellulose. The enzyme is efficient at releasing short fibres from filter paper and mechanical pulp, and acts synergistically with cellobiohydrolases. Its mode of degrading filter paper appears to be different to that of endoglucanase I from Trichoderma reesei. Furthermore, EG 28 releases colour from stained cellulose beads faster than any other enzyme tested. Peptide mapping suggests that it is not a fragment of another known endoglucanases from P. chrysosporium and peptide sequences indicate that it belongs to family 12 of the glycosyl hydrolases. EG 28 is glycosylated. The biological function of the enzyme is discussed, and it is hypothesized that it is homologous to EG III in Trichoderma reesei and the role of the enzyme is to make the cellulose in wood more accessible to other cellulases.

Progress curves--a mean for functional classification of cellulases.

The chain-end preference and processivity of the cellulases 1,4-beta-D-glucan-cellobiohydrolase I (CBH I) and 1,4-beta-D-glucan-cellobiohydrolase II (CBH II) from Trichoderma reesei and 1,4-beta-D-glucan-cellobiohydrolase 50 (CBH 50) and 1,4-beta-D-glucan-cellobiohydrolase 58 (CBH 58) from Phanerochaete chrysosporium were studied by comparing experimental degradation data on reducing end-labelled bacterial microcrystalline cellulose with computer simulations of different models. Our results with T. reesei and P. chrysosporium cellulases show that there is a common pattern of hydrolysis for CBH-I-type enzymes and another clearly distinguishable pattern for CBH-II-type enzymes, especially in the initial part of the progress curve.

Cellulose powder from Cladophora sp. algae.

The surface are and crystallinity was measured on a cellulose powder made from Cladophora sp. algae. The algae cellulose powder was found to have a very high surface area (63.4 m2/g, N2 gas adsorption) and build up of cellulose with a high crystallinity (approximately 100%, solid state NMR). The high surface area was confirmed by calculations from atomic force microscope imaging of microfibrils from Cladophora sp. algae.

New approaches to the study of tumor drug resistance.

The development of tumor drug resistance is the major obstacle to successful systemic chemotherapy. Therefore, devising methods for reversing drug resistance is a high priority and could lead to significant improvements in cancer treatment. The mechanisms of tumor drug resistance are manifold and are not well understood. The phenomenon of multidrug resistance (MDR) represents the development of resistance to most drugs, regardless of their chemical structure. Several types of MDR are known, for example, the overexpression of a cell membrane glycoprotein (P-170), increased activity of glutathione S-transferase, elevated levels of glutathione (GSH), and alterations in topoisomerase action. A partial reversal of tumor drug resistance has been achieved by the use of competitive inhibitors for the function of glycoprotein P-170, or by the inhibition of GSH synthesis; however, this strategy has not been substantially successful for improving the response of human tumors to clinical therapy. We have recently used electroporation, in conjunction with the cytotoxic drug, cisplatin (cDDP), in an attempt to circumvent drug resistance in cDDP-resistant mouse tumor cells (RIF/Ptr1). Electroporation is the application of a high-voltage electric shock which is known to create transient pores in plasma membranes of cultured cells. Electroporation plus cDDP treatment increased intracellular cDDP concentration and reversed cellular resistance to cDDP-induced cell killing.

Mortality in the British rubber industry 1946-85.

The mortality experienced by a cohort of 36,691 rubber workers during 1946-85 has been investigated. These workers were all male operatives first employed in any one of the 13 participating factories in 1946-60; all had worked continuously in the industry for a minimum period of one year. Compared with the general population, statistically significant excesses relating to cancer mortality were found for cancer of the pharynx (E = 20.2, O = 30, SMR = 149), oesophagus (E = 87.6, O = 107, SMR = 122), stomach (E = 316.5, O = 359, SMR = 113), lung (E = 1219.2, O = 1592, SMR = 131), and all neoplasms (E = 2965.6, O = 3344, SMR = 113). Statistically significant deficits were found for cancer of the prostate. (E = 128.2, O = 91, SMR = 71), testis (E = 11.0, O = 4, SMR = 36), and Hodgkin's disease (E = 26.9, O = 16, SMR = 59). Involvement of occupational exposures was assessed by the method of regression models and life tables (RMLT). This method was used to compare the duration of employment in the industry, the duration in "dust exposed" jobs, and the duration in "fume and/or solvent exposed" jobs of those dying from causes of interest with those of all matching survivors. Positive associations (approaching formal levels of statistical significance) were found only for cancers of the stomach and the lung. The results of the RMLT analysis are independent of those from the SMR analysis, and the study continues to provide limited evidence of a causal association between the risks of stomach cancer and dust exposures, and the risks of lung cancer and fume or solvent exposures in the rubber industry during the period under study.

Fiber-to-waveguide coupling using ion-milled grooves in lithium niobate at 1.3-microm wavelength.

A new method for fiber-Ti:LiNbO(3) waveguide coupling is described. Ion-milled grooves in LiNbO(3) permit repeatable, rigid location of fibers that have been chemically etched and then polished. The constituent loss mechanisms are analyzed and waveguide parameters optimized to minimize insertion loss resulting from modal mismatch by using experimental data on the optical fields. A total insertion loss of -3.1 dB has been measured for the coupler.

Rubber work and cancer--past, present and perspectives.

In the early years, the study of health in the rubber industry was hampered by lack of information in three fields. Epidemiology was just beginning, industrial hygiene had hardly begun, and little or no work had been done on the ways in which rubber chemicals affect the human body. The difficulties this created can clearly be seen in the problems of bladder cancer discovered in the industry in 1949. Since that time epidemiologic studies have become very detailed, more results are available on concentrations of material in factory atmospheres, and the effects of different chemicals on the body are being better understood. This review considers the historical problems of beta-naphthylamine exposure, summarizes the epidemiologic results on the industry to date, and considers the potential problems posed by polycyclic aromatic hydrocarbons and nitrosamines.

Measurement of some potentially hazardous materials in the atmosphere of rubber factories.

Two separate topics of work are outlined: methods for the measurement of chlorinated monomers in PVC and polychloroprene, and also methods for the measurement of these materials in factory air. Typical results which have been obtained in supplies of raw materials, in finished products, and in the working atmosphere at manufacturing operations are given. The second topic concerns the measurement of benzo[a]pyrene in the atmosphere of a tire manufacturing plant. This material is present in trace quantities in the mineral oils and carbon blacks used by the industry. The atmospheric concentrations present at various processes in this plant were measured on a daily basis over a period of two years, and the results obtained compared with results taken concurrently from an outside air station. It is shown that no significant quantities of benzo[a]pyrene are produced by tire manufacturing operations.