The thermostability of pyrogens and their removal from penicillin*,†

Welch, Henry; Price, Clifford W.; Chandler, Velma L.; Hunter, Albert C.

doi:10.1002/jps.3030340404

Cited by 15 publications

(7 citation statements)

References 7 publications

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“…To remove microbial remnants, some of the unbaked calculus was treated at 250°C for 1 h [ 28 ], and these samples were termed baked calculus. This heat treatment has been reported to effectively destroy pyrogenic substances, such as endotoxin [ 29 ]. All calculus samples thus prepared were weighed, adjusted to the appropriate concentrations, and vigorously vortexed before use for assessing cell stimulation.…”

Section: Methodsmentioning

confidence: 99%

Dental Calculus Stimulates Interleukin-1β Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes

et al. 2016

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Dental calculus is a mineralized deposit associated with periodontitis. The bacterial components contained in dental calculus can be recognized by host immune sensors, such as Toll-like receptors (TLRs), and induce transcription of proinflammatory cytokines, such as IL-1β. Studies have shown that cellular uptake of crystalline particles may trigger NLRP3 inflammasome activation, leading to the cleavage of the IL-1β precursor to its mature form. Phagocytosis of dental calculus in the periodontal pocket may therefore lead to the secretion of IL-1β, promoting inflammatory responses in periodontal tissues. However, the capacity of dental calculus to induce IL-1β secretion in human phagocytes has not been explored. To study this, we stimulated human polymorphonuclear leukocytes (PMNs) and peripheral blood mononuclear cells (PBMCs) with dental calculus collected from periodontitis patients, and measured IL-1β secretion by ELISA. We found that calculus induced IL-1β secretion in both human PMNs and PBMCs. Calculus also induced IL-1β in macrophages from wild-type mice, but not in macrophages from NLRP3- and ASC-deficient mice, indicating the involvement of NLRP3 and ASC. IL-1β induction was inhibited by polymyxin B, suggesting that LPS is one of the components of calculus that induces pro-IL-1β transcription. To analyze the effect of the inorganic structure, we baked calculus at 250°C for 1 h. This baked calculus failed to induce pro-IL-1β transcription. However, it did induce IL-1β secretion in lipid A-primed cells, indicating that the crystalline structure of calculus induces inflammasome activation. Furthermore, hydroxyapatite crystals, a component of dental calculus, induced IL-1β in mouse macrophages, and baked calculus induced IL-1β in lipid A-primed human PMNs and PBMCs. These results indicate that dental calculus stimulates IL-1β secretion via NLRP3 inflammasome in human and mouse phagocytes, and that the crystalline structure has a partial role in the activation of NLRP3 inflammasome.

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Section: Methodsmentioning

confidence: 99%

Dental Calculus Stimulates Interleukin-1β Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes

et al. 2016

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“…For dry heat to achieve the 3 D value, it requires 3 h at 140°C or 1 h at 170°C (15,34). Dry heat depyrogenation for a 3-log reduction of endotoxin requires 250°C for 30 min (41). Dry heat is considered an oxidative process-almost like a combustion process (13).…”

mentioning

confidence: 99%

Kinetics of Hydrothermal Inactivation of Endotoxins

Wilbur

Mintz

2011

Appl Environ Microbiol

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A kinetic model was established for the inactivation of endotoxins in water at temperatures ranging from 210°C to 270°C and a pressure of 6.2 ؋ 10 6 Pa. Data were generated using a bench scale continuous-flow reactor system to process feed water spiked with endotoxin standard (Escherichia coli O113:H10). Product water samples were collected and quantified by the Limulus amebocyte lysate assay. At 250°C, 5-log endotoxin inactivation was achieved in about 1 s of exposure, followed by a lower inactivation rate. This non-log-linear pattern is similar to reported trends in microbial survival curves. Predictions and parameters of several non-log-linear models are presented. In the fast-reaction zone (3-to 5-log reduction), the Arrhenius rate constant fits well at temperatures ranging from 120°C to 250°C on the basis of data from this work and the literature. Both biphasic and modified Weibull models are comparable to account for both the high and low rates of inactivation in terms of prediction accuracy and the number of parameters used. A unified representation of thermal resistance curves for a 3-log reduction and a 3 D value associated with endotoxin inactivation and microbial survival, respectively, is presented.The connection between pyrogens and fevers in patients who receive unsanitized intravenous fluids was first reported by Florence Seibert in the 1920s (32). One subset of pyrogens is bacterial endotoxins which cause the pyrogenic reactions. Endotoxins come from the outer membrane of the cell wall of Gram-negative bacteria. Endotoxins are polymeric materials represented by lipopolysaccharides (LPS) having a number average molecular weight on the order of 10,000. The active sites in endotoxins are known as lipid A (29).Pyrogen-free water is an essential material for the medical and pharmaceutical industries. Commonly known as water for injection (WFI) and sterile WFI (SWFI), the specifications require the removal of dissolved and suspended solids, sterilization, and depyrogenation (38). Distillation is the oldest method of producing pyrogen-free water (33). Distillation requires heat to separate pure water from its high boiling point impurities: inorganic solids, microorganisms, pyrogens, and all organics with boiling points higher than the operating temperature. The process also achieves sterilization of the product water. Because of energy intensity, heat recuperation by vapor compression or multiple-effect distillation is required to make the process economical.Reverse osmosis (RO) is used industrially to produce WFI in Japan (22). The RO process relies on semipermeable membranes to remove impurities from water. Due to the possibilities of membrane defects, two-stage RO is required. Since there is no heat involved in the RO process, the product water is considered WFI, unless the water is posttreated by proven methods to ensure its sterility.The thermal sterilization and depyrogenation techniques can be achieved by either wet heat or dry heat. In a wet heat application such as the commonly practiced autocl...

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“…However, the data on the inactivation of endotoxins by steam heat treatment are insufficient and contradictory. It has been reported that endotoxins were not efficiently inactivated by steam heat treatment at 121°C (19,45). However, Ogawa et al (31) recently reported that steam heat treatment was efficient in inactivating low concentrations of endotoxin, and that Escherichia coli LPS are unstable in aqueous solutions even at relatively low temperatures such as 70°C (see also reference 40).…”

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confidence: 99%

Inactivation of Escherichia coli Endotoxin by Soft Hydrothermal Processing

Miyamoto

Okano

Kasai

2009

Appl Environ Microbiol

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Bacterial endotoxins, also known as lipopolysaccharides, are a fever-producing by-product of gram-negative bacteria commonly known as pyrogens. It is essential to remove endotoxins from parenteral preparations since they have multiple injurious biological activities. Because of their strong heat resistance (e.g., requiring dry-heat sterilization at 250°C for 30 min) and the formation of various supramolecular aggregates, depyrogenation is more difficult than sterilization. We report here that soft hydrothermal processing, which has many advantages in safety and cost efficiency, is sufficient to assure complete depyrogenation by the inactivation of endotoxins. The endotoxin concentration in a sample was measured by using a chromogenic limulus method with an endotoxin-specific limulus reagent. The endotoxin concentration was calculated from a standard curve obtained using a serial dilution of a standard solution. We show that endotoxins were completely inactivated by soft hydrothermal processing at 130°C for 60 min or at 140°C for 30 min in the presence of a high steam saturation ratio or with a flow system. Moreover, it is easy to remove endotoxins from water by soft hydrothermal processing similarly at 130°C for 60 min or at 140°C for 30 min, without any requirement for ultrafiltration, nonselective adsorption with a hydrophobic adsorbent, or an anion exchanger. These findings indicate that soft hydrothermal processing, applied in the presence of a high steam saturation ratio or with a flow system, can inactivate endotoxins and may be useful for the depyrogenation of parenterals, including end products and medical devices that cannot be exposed to the high temperatures of dry heat treatments.

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The thermostability of pyrogens and their removal from penicillin*,†

Cited by 15 publications

References 7 publications

Dental Calculus Stimulates Interleukin-1β Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes

Dental Calculus Stimulates Interleukin-1β Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes

Kinetics of Hydrothermal Inactivation of Endotoxins

Inactivation of Escherichia coli Endotoxin by Soft Hydrothermal Processing

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