Bismuth Subnitrate-Catalyzed Markovnikov-Type Alkyne Hydrations under Batch and Continuous Flow Conditions

Bismuth subnitrate is reported herein as a simple and efficient catalyst for the atom-economical synthesis of methyl ketones via Markovnikov-type alkyne hydration. Besides an effective batch process under reasonably mild conditions, a chemically intensified continuous flow protocol was also developed in a packed-bed system. The applicability of the methodologies was demonstrated through hydration of a diverse set of terminal acetylenes. By simply switching the reaction medium from methanol to methanol-d4, valuable trideuteromethyl ketones were also prepared. Due to the ready availability and nontoxicity of the heterogeneous catalyst, which eliminated the need for any special additives and/or harmful reagents, the presented processes display significant advances in terms of practicality and sustainability.

Cellular Response of Neutrophils to Bismuth Subnitrate and Micronized Keratin Products In Vitro

The aim of this study was to assess the effect of bismuth subnitrate and micronized keratin on bovine neutrophils in vitro. We hypothesized that recruitment and activation of neutrophils into the teat canal and sinus are the mechanisms of action of bismuth subnitrate and keratin-based teat sealant formulations. To test this, a chemotaxis assay (Experiment 1) and a myeloperoxidase (MPO) assay (Experiment 2) were conducted in vitro. Blood was sampled from 12 mid-lactation dairy cows of variable ages. Neutrophils were extracted and diluted to obtain cell suspensions of approximately 106 cells/mL. In Experiment 1, test substances were placed in a 96-well plate, separated from the cell suspension by a 3 µm pore membrane and incubated for 3 h to allow neutrophils to migrate through the membrane. In Experiment 2, neutrophils were exposed to the test products and the amount of MPO released was measured by optical density. Results showed that neutrophils were not activated by bismuth or keratin products (p < 0.05) in all of the tests performed. These results suggest that the mechanisms of action of bismuth subnitrate and keratin-based teat sealants do not rely on neutrophil recruitment and activation in the teat canal and sinus after treatment.

Effect of Bismuth Subnitrate Teat Canal Sealant with Ampicillin-Cloxacillin Combination in Control of Bovine Mastitis in Selected Farms in Kenya

This study presents the results of effect of a combination of bismuth subnitrate teat canal sealant (Boviseal® -Bimeda® Animal Health, Ireland) and the antibiotic Ampicillin & Cloxacillin (Bovaclox® DC-Norbrook Laboratories Ltd-UK) when used during the dry period on occurrence of mastitis 100 days post-calving. The objectives of this study were: to determine the effect of Boviseal® teat canal sealant in combination with Bovaclox® DC in control of dairy cow mastitis 100 days after calving; to determine bacterial pathogens causing mastitis in the selected farms and to determine risk factors for occurrence of dairy mastitis in the selected farms. This controlled field trial was carried out in two Kenyan dairy farms: Chemusian Farm in Nakuru County and Gicheha Farm in Kiambu County. 156 dairy cows were used in the study. Healthy cows with no history of mastitis in their current lactation were recruited. They were randomly placed into either of the two study groups: the control and the test group. The Control group received Bovaclox® DC while the Test group received the Bovaclox® DC followed by Boviseal®. The cows were followed during the entire dry period and 100 days post-calving monitoring for mastitis occurrence. Cows in the control group were more susceptible to mastitis 100 days post-calving compared to cows in the treatment group (P<0.001, RR=4.4, OR=17.7). Of the bacterial pathogens, coagulase negative Staphylococci (CNS) were the most common pathogens isolated from mastitic milk at 34.6 % followed by Micrococcus spp. (9.0%). Other bacteria isolated were Streptococcus agalactiae (3.8%), Staphylococcus aureus (1.9%); Escherichia coli (0.6%) and various bacterial mixtures. Results of logistic regressions at P≤0.05 showed that farm, position of the quarter, type of barn floor and type of treatment were significantly associated with occurrence of mastitis. Cows in Gicheha farm whose barn floor was earthen, those cows in the control group and hindquarters were risk factors for mastitis (RR=1.5, 4.4 and 1.18 respectively). The results of this study showed that Bovaclox® DC + Boviseal® teat canal sealant combination applied during the dry period is more effective in controlling bovine mastitis 100 days post-calving compared to the use of Bovaclox® DC alone. The study thus recommends the use of Bovaclox® DC + Boviseal® dry cow combination for control of bovine mastitis.

Barium- and Bismuth-loaded Clinoptilolite Micro- and Nano-Particles as Proposed New Efficient Contrast Agents

Aim and Objective: Clinoptilolite is one of the natural zeolites. Clinoptilolite particles have a high surface area, negative surface charge, cation adsorption and exchange capacities. Barium sulfate (BaSO4) and bismuth subnitrate (Bi5H9N4O22) suspensions have been used for upper and lower gastrointestinal imaging but Ba2+ and Bi3+ ions are toxic. In the present study, the feasibility of the application of Ba2+- and Bi3+-loaded clinoptilolite micro- and nano-particles in medical imaging was investigated. Materials and Methods: Nanoparticles and microparticles of natural clinoptilolite were loaded with Ba2+ and Bi3+ ions. Radiopacities of loaded particles were measured and compared with those of BaSO4 and Bi5H9N4O22. Results: Ba2+- and Bi3+-loaded clinoptilolite nanoparticles and microparticles showed more intense X-ray opacities than BaSO4 and Bi5H9N4O22 with equimolar concentrations. Moreover, Ba2+- and Bi3+-loaded clinoptilolite nanoparticles more intensely absorbed X-ray than respective loaded microparticles. Conclusion: The present study proposes Ba2+- and Bi3+-loaded clinoptilolite nanoparticles and microparticles as new, safe, efficient, and inexpensive contrast agents.

Comparative efficacy of teat sealants given prepartum for prevention of intramammary infections and clinical mastitis: a systematic review and network meta-analysis

A systematic review and network meta-analysis were conducted to assess the relative efficacy of internal or external teat sealants given at dry-off in dairy cattle. Controlled trials were eligible if they assessed the use of internal or external teat sealants, with or without concurrent antimicrobial therapy, compared to no treatment or an alternative treatment, and measured one or more of the following outcomes: incidence of intramammary infection (IMI) at calving, IMI during the first 30 days in milk (DIM), or clinical mastitis during the first 30 DIM. Risk of bias was based on the Cochrane Risk of Bias 2.0 tool with modified signaling questions. From 2280 initially identified records, 32 trials had data extracted for one or more outcomes. Network meta-analysis was conducted for IMI at calving. Use of an internal teat sealant (bismuth subnitrate) significantly reduced the risk of new IMI at calving compared to non-treated controls (RR = 0.36, 95% CI 0.25–0.72). For comparisons between antimicrobial and teat sealant groups, concerns regarding precision were seen. Synthesis of the primary research identified important challenges related to the comparability of outcomes, replication and connection of interventions, and quality of reporting of study conduct.