Rheumatology expertise in advising immunocompromised healthcare workers: Insights from a survey of Australian rheumatologists

BACKGROUND

Healthcare workers (HCW) with an inflammatory disease may be at increased risk of infections and their complications, however there is no evidence to guide specific measures to reduce the risk of immunocompromised HCW acquiring infection in the workplace. This cross-sectional study aimed to define the attitudes of rheumatologists and rheumatology trainees towards counselling immunocompromised healthcare workers about additional workplace precautions to minimise workplace risk of infection.

METHODS

A cross-sectional survey was administered via Zoom poll during a webinar held in August 2020. Participants were Victorian and Tasmanian members of the Australian Rheumatology Association, which includes consultant rheumatologists and rheumatology trainees. Descriptive statistics were used to analyse survey responses.

RESULTS

Of the 52 participants, 41 provided care to at least one immunocompromised healthcare worker. 21 out of 52 participants estimated that the majority of these patients sought their advice about infection risk in the workplace. The most common source of information for counselling patients on workplace infection risks were colleagues (38/50). Participants were most confident in providing information on influenza and hepatitis but less confident in providing information in tuberculosis, shingles and COVID-19. Most participants believed employers of immunocompromised HCW should play a role in providing advice on managing infection risks in the workplace.

CONCLUSION

Our study reveals a level of uncertainty and discomfort amongst rheumatologists in providing recommendations to immunocompromised healthcare workers about managing their workplace risk of infection. We recommend the development of a framework to guide the clinician in making individualised recommendations for immunocompromised HCW.

Ketonitrosamines as metabolites of methyl-n-amylnitrosamine (MNAN) and its hydroxy derivatives in the rat

In a previous study of the metabolism of methyl-n-amylnitrosamine (MNAN) in the rat, 2- to 5-hydroxy-MNAN (HO-MNAN) were provisionally identified as metabolites and the identity of 4-HO-MNAN was confirmed by mass spectrometry. We now describe syntheses and mass and other spectra for 2- to 5-oxo-MNAN. Two previously unidentified MNAN metabolites were shown to be 3- and 4-oxo-MNAN. In addition to 4-HO-MNAN, we confirmed 3-HO-, 4-oxo- and (less certainly) 2-HO-MNAN as urinary MNAN metabolites by GLC-MS of HPLC fractions. Analysis with and without beta-glucuronidase treatment showed that the urinary HO-MNANs occurred as their beta-glucuronides. MNAN (25 mg/kg injected i.p.) had a blood half-life of 21 min in adult male rats. The blood also contained 4-HO- and 4-oxo-MNAN, which showed maximum levels that were 13 and 26% respectively of that for MNAN, and were cleared more slowly than MNAN. On incubation for 3 h with MNAN, rat esophagus produced 3- and 4-oxo-MNAN in yields that were 5% of those for the corresponding HO-MNANs. For MNAN metabolism, the 4-oxo-/4-HO-MNAN ratio of metabolites was 5% for adult rat liver and was 22% for adult hamster liver and 9-day-old rat liver. On incubation with 4-HO-MNAN for 3 h, oxidation to 4-oxo-MNAN was 16-25% for adult hamster or 9-day-old rat liver slices and for adult hamster liver homogenate. Homogenate activity was concentrated in the microsomal fraction, for which NAD was a more effective co-factor than NADP. A bacterial alcohol dehydrogenase oxidized 4-HO- to 4-oxo-MNAN in 38% yield/3 h. None of these preparations oxidized 2-HO- to 2-oxo-MNAN. It was concluded that 3- and 4-oxo-MNAN were metabolites of MNAN, apparently (for 4-oxo-MNAN) via HO-MNAN oxidation by a microsomal NAD-dependent enzyme, that 4-HO- and 4-oxo-MNAN formation was a major route of MNAN metabolism, and that 4-oxo-MNAN might play a role in MNAN carcinogenesis.

Induction of glutathione S-transferases in genetically inbred male mice by dietary ethoxyquin hydrochloride

1. Constitutive and ethoxyquin hydrochloride (EQ-HCl)-induced hepatic glutathione (GSH) S-transferase, GSH reductase, and GSH peroxidase activities were determined in 5 strains of 8-10 week old inbred male mice. 2. The constitutive GSH S-transferase (GST) activity varied from 2.9 (SJL/JCR) to 8.9 (C57BL/6NCR) mumol product formed/min/mg protein and the corresponding values for the EQ-HCl-treated mice were in the range of 15.3-25.3 mumol product formed/min/mg protein. 3. EQ-HCl induced GST activity in all the strains examined and this contrasted to the induction activity of Aroclor 1254 which was strain-dependent. GST activity was induced 2.9-fold in Aroclor 1254-responsive (C57BL/6) and 2.8-fold in non-responsive (DBA/2) mice, respectively.

Constitutive and Aroclor 1254-induced hepatic glutathione S-transferase, peroxidase and reductase activities in genetically inbred mice

1. Constitutive and Aroclor 1254-induced hepatic glutathione (GSH) S-transferases, GSH peroxidase and GSH reductase activities were determined in 12 strains of 8-10 week-old inbred male mice. 2. The constitutive GSH S-transferase activity varied from 2.5 (SJL/JCR) to 8.9 (C57BL/6N) mumol/min/mg protein and the corresponding values for the Aroclor 1254-treated mice were in the range of 7.1-23.0 mumol/min/mg protein. Aroclor 1254 significantly induced GSH S-transferase activity in all mice, however, significant interstrain differences were found in inducibility. 3. Aroclor 1254-treatment caused a 4.2-fold induction of GSH S-transferase in NFS/NCR but only a 1.4-fold increase in AKR/NCR mice. Aroclor 1254 significantly induced GSH reductase in all strains studied while GSH peroxidase activity decreased in these mice. 4. The range of hepatic GSH levels in control and Aroclor 1254-treated mice was relatively narrow for both groups (6.59-11.25 microM/g wet tissue).