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From 2002 to 2013, bovine tuberculosis (bTB) caused by Mycobacterium bovis (M. bovis) has been detected on numerous dairies in California. In total, twelve herds had bTB detected and are included in the case series which describes these recent outbreaks and discusses potential pathways of introduction. Epidemiological investigations to determine the initial source of bTB in each herd included obtaining data on likely pathways of pathogen introduction. Pathways included purchasing cattle, use of heifer-raising operations, commingling of cattle at greater risk of exposure to infected cattle with cattle destined for California dairies, contact with infected wildlife, exposure to humans with bTB infections, community and neighboring herds and others. Epidemiologic and molecular typing data confirmed the source of infection in 3 herds and probable sources of infection in 2 herds. In the 7 remaining herds described in this case series an epidemiologic link to a source could not be determined and molecular typing results did not associate M. bovis isolates acquired from these herds with another specific U.S. herd or U.S.-born animal. Preventing new introductions of M. bovis onto California dairies will require rigorous epidemiologic investigation of all the potential pathways of introduction discussed here. The root cause(s) of bTB on California dairies is certainly multifactorial with complex interactions of herd management practices, importation of cattle at greater risk of exposure to infected cattle, and the potential of human M. bovis exposure. The extensive use of molecular typing has improved epidemiologists' ability to narrow the scope of potential sources.

SummaryAssembly factors (AFs) prevent premature translation initiation on small (40S) ribosomal subunit assembly intermediates by blocking ligand binding. However, it is unclear how AFs are displaced from maturing 40S ribosomes, if or how maturing subunits are assessed for fidelity, and what prevents premature translation initiation once AFs dissociate. Here we show that maturation involves a translation-like cycle whereby the translation factor eIF5B, a GTPase, promotes joining of large (60S) subunits with pre-40S subunits to give 80S-like complexes, which are subsequently disassembled by the termination factor Rli1, an ATPase. The AFs Tsr1 and Rio2 block the mRNA channel and initiator tRNA binding site, and therefore 80S-like ribosomes lack mRNA or initiator tRNA. After Tsr1 and Rio2 dissociate from 80S-like complexes Rli1-directed displacement of 60S subunits allows for translation initiation. This cycle thus provides a functional test of 60S subunit binding and the GTPase site before ribosomes enter the translating pool.

Background We have shown that serine proteases in German cockroach extract increase TNF-α–induced expression of IL-8 in human bronchial epithelial cells. The mechanism by which cockroach proteases regulate cytokine expression is unknown; however, protease-activated receptors (PARs) might play a role. Objective We sought to determine the role of PARs and extracellular-signal-regulated kinase (ERK) in cockroach-induced regulation of IL-8 expression. Methods 16HBE14o- human bronchial epithelial cells were treated with the specific PAR-1 and PAR-2 agonists, TFRIFD and SLIGKV, respectively. IL-8 transcription was assessed by transiently transfecting cells with a luciferase-tagged IL-8 promoter construct, and in some cases, dominant-negative expression vectors. To block PAR cleavage, antibodies against the cleavage region of PAR-1 and PAR-2 were used. ERK phosphorylation was determined by Western blot. Results Although both PAR-1 and PAR-2 were endogenously expressed in 16HBE14o- cells, selective activation of PAR-2 but not PAR-1 mimicked the effect of cockroach extract on IL-8 expression. Using a blocking antibody against cleavage of PAR-2 but not PAR-1 attenuated cockroach-extract-induced responses, suggesting that cockroach proteases cleave PAR-2. Treatment of cells with cockroach extract and SLIGKV each increased phosphorylation of ERK. Chemical or genetic inhibition of Ras and mitogen-activated protein kinase/ERK (MEK), upstream activators of ERK, each attenuated cockroach- and PAR-2–induced IL-8 transcription. Conclusion Cockroach proteases and PAR-2 activation synergistically increase TNF-α–induced IL-8 transcription via activation of ERK. These data suggest an important role for PAR-2 and ERK activation in the regulation of cytokine expression in airway epithelium in response to cockroach proteases.

Late in their maturation, nascent small (40S) ribosomal subunits bind 60S subunits to produce 80S-like ribosomes. Because of the analogy of this translation-like cycle to actual translation, and because 80S-like ribosomes do not produce any protein, it has been suggested that this represents a quality control mechanism for subunit functionality. Here we use genetic and biochemical experiments to show that the essential ATPase Fap7 promotes formation of the rotated state, a key intermediate in translocation, thereby releasing the essential assembly factor Dim1 from pre-40S subunits. Bypassing this quality control step produces defects in reading frame maintenance. These results show how progress in the maturation cascade is linked to a test for a key functionality of 40S ribosomes: their ability to translocate the mRNA⋅tRNA pair. Furthermore, our data demonstrate for the first time that the translation-like cycle is a quality control mechanism that ensures the fidelity of the cellular ribosome pool.

A soy-protein isolate diet that was deficient in methionine (Met), zinc (Zn), riboflavin, vitamin B-6 and choline for chick growth (Assay 1) was used to study individual or multiple deficiencies of several of these nutrients. In all cases, adding all three deficient nutrients together resulted in growth responses that were superior to those resulting from supplementation with any pairs of deficient nutrients. In Assay 2, single addition of Zn but not of methionine or riboflavin produced a growth response, but the combination of either Zn and Met or Zn and riboflavin resulted in growth responses that were greater than the response elicited by Zn alone. Assay 3 involved individual or multiple deficiencies of choline, riboflavin and vitamin B-6, and individual additions suggested that choline was first limiting. Choline + riboflavin supplementation, however, produced marked growth and gain:food responses that were far greater than those resulting from supplemental choline or riboflavin alone. Moreover, the growth response to a combination of choline + pyridoxine (PN) was also greater than that obtained from any of the three nutrients fed alone; even PN + riboflavin (in the absence of choline) produced responses greater than those observed with the unsupplemented negative-control diet. In Assay 4, chicks responded to individual additions of riboflavin, PN or Met, and in Assay 5, to either riboflavin or PN; all two-way combinations resulted in growth rates that were far greater than those occurring with any single addition. The data from these experiments show that unlike the situation with three deficient amino acids, the expected responses to first-, second- and third-limiting B-vitamins or deficient vitamins combined with deficient levels of Zn or Met do not follow the expected pattern of response to first-, further response to first- and second- and an even further response to first-, second- and third-limiting nutrients.

A 60-year-old man underwent end-to-end aortobifemoral (ABF) bypass for occlusive disease. 1,2 He subsequently underwent a right-to-left femorofemoral bypass (FFB) for occlusion of the left limb of the ABF. He was referred 4 years later with fever, malaise, and purulent drainage from the right groin. A computed tomographic scan demonstrated fluid surrounding the FFB and the right limb of the ABF (A). A segment of infrarenal aorta proximal to the ABF graft appeared normal. Standard inframesocolic exposure was obtained via the previous midline incision. No fluid was evident at the graft bifurcation, and it appeared well incorporated. The residual infrarenal aorta was dissected free and prepared for an anastomosis. Openings were made in the ventromedial aspect of the obturator membrane bilaterally while standard medial exposure of the above-knee popliteal arteries was performed. Expanded polytetrafluoroethylene grafts ((W.L. Gore & Association, Inc., Tempe, Ariz) Intering; 8 mm 40 cm) were tunneled from the popliteal sites through the obturator foramina into the abdomen. (B) The limbs of a bifurcated expanded polytetrafluoroethylene graft (Gore-Tex; 18 9 mm) were cut 1 cm from the graft bifurcation, and graft-to-graft anastomoses were performed bilaterally. After systemic anticoagulation, the infrarenal aorta and the limbs of the ABF were clamped. The limbs were then transected, ligated, and advanced antegrade along the iliac tunnels. The residual body of the ABF graft was excised. The new bifurcated graft was sewn end to end to the infrarenal aorta proximally. The graft-to-graft anastomoses were assessed for hemostasis before the grafts were pulled through the previously fashioned obturator tunnels. End-to-side anastomoses were performed distally. The wounds were closed and covered with occlusive dressings before complete excision of the residual ABF limbs and the FFB via bilateral femoral and suprapubic incisions. The femoral and suprapubic incisions were packed, and the patient was maintained on chronic oral antibiotic therapy. At 24 months, he had no evidence of recurrent infection and was ambulatory at home. A follow-up computed tomographic scan demonstrated no fluid collections and patent grafts (C; cover image). The treatment of infected ABF grafts is a difficult problem. Options include in situ reconstruction with femoral vein, cryopreserved allografts, or antibiotic-impregnated synthetic grafts. Extra-anatomic reconstruction to the popliteal level is not an ideal solution secondary to poor patency. We suggest that reconstruction with synthetic bilateral obturator bypass is a viable option if there is adequate residual infrarenal aorta. This procedure allows for complete treatment of the femoral pathology and should have improved patency compared with longer extra-anatomic bypasses.

Crude cockroach extract elicited positive skin tests in 50% of patients with positive and in 4% with negative environmental history for cockroach exposure, suggesting a possible role of cockroach in perennial atopic disease. Three major allergens in crude American and German cockroach extracts have been identified using sequential purification steps on Sephadex G-75, diethylaminoethyl (DEAE) cellulose, and agarose gel electrophoresis. Cr-I elicits positive skin tests in 70% of patients sensitive to the crude extracts. It has a molecular weight of approximately 25,500 daltons, is highly acidic, and resists boiling for four hours. Boiling in 4 N acetic acid completely abolishes its allergenicity. The purified allergen elicits positive skin tests at a concentration of 3 μg/ml and is capable of inducing >50% histamine release from sensitive leukocytes at 0.05 ng/ml. A second antigen, Cr-II, elicits positive skin tests also in approximately 70% of cockroach-sensitive individuals, has a molecular weight of approximately 63,000 to 65,000 daltons, and has similar heat stability and acid hydrolysis characteristics to Cr-I. A third, less well-characterized antigen, Cr-III, has a molecular weight