Trends in SARS-CoV-2 cycle threshold values in the Czech Republic from April 2020 to April 2022.

The inability to predict the evolution of the COVID-19 epidemic hampered abilities to respond to the crisis effectively. The cycle threshold (Ct) from the standard SARS-CoV-2 quantitative reverse transcription-PCR (RT-qPCR) clinical assay is inversely proportional to the amount of SARS-CoV-2 RNA in the sample. We were interested to see if population Ct values could predict future increases in COVID-19 cases as well as subgroups that would be more likely to be affected. This information would have been extremely helpful early in the COVID-19 epidemic. We therefore conducted a retrospective analysis of demographic data and Ct values from 2,076,887 nasopharyngeal swab RT-qPCR tests that were performed at a single diagnostic laboratory in the Czech Republic from April 2020 to April 2022 and from 221,671 tests that were performed as a part of a mandatory school surveillance testing program from March 2021 to March 2022. We found that Ct values could be helpful predictive tools in the real-time management of viral epidemics. First, early measurement of Ct values would have indicated the low viral load in children, equivalent viral load in males and females, and higher viral load in older individuals. Second, rising or falling median Ct values and differences in Ct distribution indicated changes in the transmission in the population. Third, monitoring Ct values and positivity rates would have provided early evidence as to whether prevention measures are effective. Health system authorities should thus consider collecting weekly median Ct values of positively tested samples from major diagnostic laboratories for regional epidemic surveillance.

A mutation in the SAA1 promoter causes hereditary amyloid A amyloidosis.

Amyloid A amyloidosis is a serious clinical condition resulting from the systemic deposition of amyloid A originating from serum amyloid A proteins with the kidneys being the most commonly and earliest affected organ. Previously described amyloid A amyloidosis is linked to increased production and deposition of serum amyloid A proteins secondary to inflammatory conditions arising from infectious, metabolic, or genetic causes. Here we describe a family with primary amyloid A amyloidosis due to a chr11:18287683 T>C (human genome version19) mutation in the SAA1 promoter linked to the amyloidogenic SAA1.1 haplotype. This condition leads to a doubling of the basal SAA1 promoter activity and sustained elevation of serum amyloid A levels that segregated in an autosomal dominant pattern in 12 genetically affected and in none of six genetically unaffected relatives, yielding a statistically significant logarithm of odds (LOD) score over 5. Affected individuals developed proteinuria, chronic kidney disease and systemic deposition of amyloid composed specifically of the SAA1.1 isoform. Tocilizumab (a monoclonal antibody against the interleukin-6 receptor) had a beneficial effect when prescribed early in the disease course. Idiopathic forms represent a significant and increasing proportion (15-20%) of all diagnosed cases of amyloid A amyloidosis. Thus, genetic screening of the SAA1 promoter should be pursued in individuals with amyloid A amyloidosis and no systemic inflammation, especially if there is a positive family history.

Determination of asialotransferrin in the cerebrospinal fluid with the HPLC method.

BACKGROUND: Identification of the content of asialotransferrin in the cerebrospinal fluid is a diagnostic method for childhood-onset ataxia and central nervous system hypomyelination (CACH), also known as vanishing white matter disease (VWM), and also for other types of CNS disorders. METHODS: In our work, we have determined the value of the ratio of the asialo form of transferrin to the total transferrin in the CSF using the commercially used Variant(TM) Bio-Rad system for the determination of carbohydrate-deficient transferrin (CDT) in serum. The peak corresponding to the asialo form of transferrin was identified with electrophoresis with subsequent immunofixation and mass spectrometry (MALDI-TOF/TOF). RESULTS: The intra-assay and inter-assay variations of the asialotransferrin value in CSF were 6.8% and 10.2%, respectively. Analysing CSF samples of 60 subjects (23 men aged 22-68 years and 37 women aged 18-77 years) with normal transferrin values and normal cytology as well as biochemistry parameters in the cerebrospinal fluid, and without apparent signs of neurological disorders, we have found the presence of 25.2 +/- 8.2% asialotransferrin. CONCLUSION: Except for the need to obtain approximately 1.5 mL of cerebrospinal fluid and a tenfold concentrating of the sample, there is no need to conduct any modifications of the preparation procedure for the analytic sample and chromatographic separation normally used for serum samples. The HPLC method of asialotransferrin determination in CSF provides clinically useful results.

Proteomic analysis uncovers a metabolic phenotype in C. elegans after nhr-40 reduction of function.

Caenorhabditis elegans has an unexpectedly large number (284) of genes encoding nuclear hormone receptors, most of which are nematode-specific and are of unknown function. We have exploited comparative two-dimensional chromatography of synchronized cultures of wild type C. elegans larvae and a mutant in nhr-40 to determine if proteomic approaches will provide additional insight into gene function. Chromatofocusing, followed by reversed-phase chromatography and mass spectrometry, identified altered chromatographic patterns for a set of proteins, many of which function in muscle and metabolism. Prompted by the proteomic analysis, we find that the penetrance of the developmental phenotypes in the mutant is enhanced at low temperatures and by food restriction. The combination of our phenotypic and proteomic analysis strongly suggests that NHR-40 provides a link between metabolism and muscle development. Our results highlight the utility of comparative two-dimensional chromatography to provide a relatively rapid method to gain insight into gene function.