Size distribution and relationship of airborne SARS-CoV-2 RNA to indoor aerosol in hospital ward environments

Aerosol particles proved to play a key role in airborne transmission of SARS-CoV-2 viruses. Therefore, their size-fractionated collection and analysis is invaluable. However, aerosol sampling in COVID departments is not straightforward, especially in the sub-500-nm size range. In this study, particle number concentrations were measured with high temporal resolution using an optical particle counter, and several 8 h daytime sample sets were collected simultaneously on gelatin filters with cascade impactors in two different hospital wards during both alpha and delta variants of concern periods. Due to the large number (152) of size-fractionated samples, SARS-CoV-2 RNA copies could be statistically analyzed over a wide range of aerosol particle diameters (70-10 µm). Our results revealed that SARS-CoV-2 RNA is most likely to exist in particles with 0.5-4 µm aerodynamic diameter, but also in ultrafine particles. Correlation analysis of particulate matter (PM) and RNA copies highlighted the importance of indoor medical activity. It was found that the daily maximum increment of PM mass concentration correlated the most with the number concentration of SARS-CoV-2 RNA in the corresponding size fractions. Our results suggest that particle resuspension from surrounding surfaces is an important source of SARS-CoV-2 RNA present in the air of hospital rooms.

Dickkopf-related protein 1 expression in bone marrow of multiple myeloma patients: correlation with bone disease and plasma cell malignancy type

BACKGROUND

Previous studies have pointed out the role of dickkopf-related protein 1 (DKK 1) - Wnt inhibitor, which is essential for osteoblast functioning, in the development of osteolytic lesions in multiple myeloma (MM).

AIM

To assess the DKK 1 expression displayed by myeloma cells in bone marrow trephine biopsies of patients with and without osteolytic lesions, and in different malignancy grades of the disease.

METHODS

The expression level of DKK 1 was assessed immunohistochemically in bone marrow of 49 MM patients presented with and without osteolytic lesions (the 1^st and the 2^nd group, respectively).

RESULTS

Levels of weak, moderate, and strong DKK 1 expression were distributed - as 43.33, 27.78 and 25.56%, and 63.91, 18.80, and 1.50%, respectively when evaluating the samples obtained from the 1^st and the 2^nd group. Statistically significant differences were found when the levels of DKK 1 expression in the 1^st and the 2^nd group were compared (χ² = 51; df = 3; p < 0.001).

CONCLUSIONS

DKK 1 contributes to the development of osteolytic lesions in MM. The present study provides morphological evidence that inhibition in Wnt signaling may lead to bone damage observed in the advanced stage of the disease.

Survival analysis of oropharyngeal squamous cell carcinoma patients linked to histopathology, disease stage, tumor stage, risk factors, and received therapy

BACKGROUND

Survival of oropharyngeal squamous cell carcinoma (OSCC) patients depends on the risk and environmental factors, tumor biology, achievements in diagnostics and treatment approaches.

AIM

To perform a survival analysis of the patients with OSCC treated over a 10-year period in a single hospital in Latvia linking these data to histopathological findings, risk factors and received therapy.

MATERIALS AND METHODS

The main outcome measures were overall and disease-specific survival (OS and DS) along with histopathology analysis.

RESULTS

Kaplan - Meier survival analysis showed better survival for females, younger patients lacking bad habits, operated and received radiotherapy, with lower T grade and disease stage. Cox regression showed diminished early death risk in patients with lower T grade, no regional metastases (N0) and bad habits, operated and received radiotherapy. A vast majority of tumors were localized in palatine tonsils and the base of the tongue. The localization did not correlate with mean survival time/survival. Lower OS (p = 0.03) and DS (p = 0.026) were estimated for patients with pharyngeal wall and tonsillar involvement compared to tumors localized in the soft palate. A histological variant of tumor seemed irrelevant estimating OS and DS, whereas therapeutic modalities significantly affected survival.

CONCLUSIONS

OSCC patients with lower T grade, N0 status, lacking bad habits, and surgically treated had better survival.

Association of active human herpesvirus-6 (HHV-6) infection with autoimmune thyroid gland diseases

OBJECTIVES

Viral infections frequently have been cited as important environmental factors implicated in the onset of autoimmune thyroiditis (AIT). The aim of this study was to determine the involvement of HHV-6 infection in the development of autoimmune thyroiditis.

METHODS

This study included 45 patients (42 female and 3 male; median age 47.00 IQR 38.50-57.00) with histologically, laboratory, and clinically confirmed autoimmune thyroiditis, as well as 30 autopsied subjects (26 female and 4 male; median age 58.50, IQR 51.50-67.00) without thyroid pathologies and 30 healthy blood donors (25 female and 5 male; median age 33.50, IQR 27.75-44.25) as controls. Results were obtained by applying molecular virology and immunohistochemistry techniques.

RESULTS

The presence of persistent HHV-6 infection in AIT patients was significantly higher (p 0.0058) than in the control group (44/45 (98%) vs. 23/30 (77%), respectively). Also, a significantly higher frequency of HHV-6 activation marker (U79/80 mRNA) was found in patients' thyroid gland tissue samples with AIT in comparison with the control group (18/44 (41%) vs. 1/17 (6%), respectively; p 0.0118). The median HHV-6 load was found to be higher in patients with active viral infection than in patients without it (2147, IQR 971-4188 vs. 551, IQR 145-1589 copies/1×10⁶ cells; p 0.003). The presence of HHV-6 antigen expression was demonstrated in intrafollicular cellular clusters and immunohistochemistry indicated thyrocytes in the follicle wall.

CONCLUSIONS

These findings provide evidence of strong HHV-6 infection association with AIT development.

The outcome of the movement disorder in methcathinone abusers: clinical, MRI and manganesemia changes, and neuropathology

BACKGROUND AND PURPOSE

There is limited knowledge regarding the long-term outcome of the methcathinone/manganese-induced movement disorder. Our purpose was to define prognosis in intravenous methcathinone abusers affected by this distinctive disorder attributed to manganese (Mn) toxicity. Also, neuropathology from a globus pallidus region biopsy from a former user is reported.

METHODS

Eighteen methcathinone abusers were categorized as active (five), discontinued (four) or former (nine) users. They were reassessed after a median of 32.5 months (range 3.4-59.6) clinically, on rating scales, and with MRI and blood Mn levels. The biopsy was examined ultrastructurally.

RESULTS

Overall the group showed a slight tendency to deterioration at follow-up on clinical assessment of motor functioning, especially the active users. No significant change occurred on parkinsonian rating scale reassessment. Significant reduction in Mn levels occurred in former users, and decreased T1-weighted hyperintensity on basal ganglia MRI occurred in 3 of 4 former and 2 of 3 discontinued users, despite lack of clinical improvement. The biopsy consisted of white matter showing decompacted myelin sheaths and frequent abnormalities of mitochondria.

CONCLUSIONS

No improvement in this Mn-induced movement disorder occurs after cessation of methcathinone abuse despite improvement of Mn blood levels and/or MRI abnormalities. Ultrastructural abnormalities in a former user confirm structural damage to white matter is associated with the disorder. Methcathinone/Mn toxicity is an important, disabling and permanent medical sequel of intravenous drug abuse in the former Soviet Union.

The proper delivery pressure for cardioplegic solution in neonatal cardiac surgery - an investigation of biomechanical and structural properties of neonatal and adult coronary arteries

When cardioplegic solution is injected into coronary arteries with a pump in order to ensure myocardial protection, it is necessary to determine the correct delivery pressure to avoid damage of the heart. Biomechanical and structural properties of the neonatal coronary artery wall should be taken into account when determining the delivery pressure. We investigated twelve coronary artery specimens without cardiac pathology retrieved from autopsies of neonates 9.3 ± 9.7 days old and compared them to adult specimens with no detected atherosclerosis. There was a rapid increase in the strain until the inner pressure reached 80 - 100 mmHg, whilst the increase of stress in the wall of the neonatal coronary arteries was less rapid. When the pressure exceeded 100 mmHg, the increase in the strain slowed down, whilst the wall stress and modulus of elasticity began to increase rapidly. Morphologic examination of tensile properties revealed prominent affection of the vascular wall of the neonates, with accentuated redistribution (loosening) of medial myocytes and the adventitial vasa vasorum. Collectively, a raised inner pressure applied to cardioplegic solution injected into the coronary artery of a neonate may increase the risk of structural damage to the vascular wall.

Kynurenine and neopterin in chronic glomerulonephritis

The results of our clinical observations of 102 patients with chronic glomerulonephritis with normal renal function have shown that hyperkynureninemia in 22.5% of patients develops in cases of pyridoxal-5-phosphate deficiency (hyperkynureninemia after peroral L-tryptophan load), but in 14.8% of patients through the stimulation of the cellular immune system (hyperkynureninemia at fasting state, increase of serum neopterin concentration). In all 20 patients with chronic renal failure hyperkynureninemia develops due to decreased renal function (increased serum kynurenine, neopterin and creatinine concentrations). Therefore, L-tryptophan peroral loading test with the determination of serum concentration of kynurenine before and at 3rd hour after the load, as well as the detection of serum concentration of neopterin and creatinine are helpful for the differentiation of following pathologies in patients with chronic glomerulonephritis: pyridoxal-5-phosphate deficiency, cellular immune stimulation and chronic renal failure.

Demonstration of collagen type VI and alpha-smooth muscle actin in renal fibrotic injury in man

BACKGROUND

Overproduction of collagenous fibres types I and III is a common finding of fibrotic injury. Collagen type VI is generally associated with type I. Appearance of fibroblasts expressing alpha-smooth muscle actin (ASMA) and their role in fibrogenesis has been partly defined. However, correlation between renal fibroblasts and accumulation of microfibrillar collagen type VI, as well as its exact distribution, is not fully delineated. This study was undertaken to investigate these issues using a complex morphological approach.

METHODS

Morphological examination included immunohistochemical detection of the collagen type VI and ASMA, relying on a streptavidin-biotin-peroxidase-based technique, and electron microscopy.

RESULTS

Collagen type VI was strongly expressed in areas of fibrotic injury, although mild expression was always revealed in renal interstitium. Glomerular immunoreactivity with the anti-collagen type VI antibody was almost nil excepting cases of diabetic glomerulosclerosis and amyloid nephrosis. Glomerular nodules in cases of diabetes displayed intense reactivity. Mesangial, as well as discontinuous peripheral deposition of collagen along the glomerular basement membrane, was noticed in case of amyloidosis. Ultrastructurally, cross-banded collagen microfibrils were found in renal interstitium in close association with the fibroblast membrane. Moreover, fibrillar elements revealing tubular structure and fine filamentous material were observed between cross-banded microfibrils. Some of fibroblasts exhibited bundles of microfilaments in their cytoplasm. An increased number of ASMA-positive cells was detected in fibrotic interstitium. An intense concentric network made up of actin-bearing cells surrounded glomerular capillaries in the case of crescentic glomerular lesions.

CONCLUSIONS

Markedly increased deposition of collagen type VI takes place in renal fibrotic lesions. Simultaneously, interstitial fibrotic areas appeared to contain a great number of fibroblasts sharing morphological characteristics of classic fibroblasts and smooth muscle cells. Detailed examination of coexistence of these two interstitial phenomena should further clarify the cellular mechanisms involved in renal interstitial fibrosis.

A quantitative immunohistochemical study of the expression of mesangial alpha-smooth muscle actin and the proliferation marker Ki-67 in glomerulonephritis in man

Using a specific marker 1A4 (DAKO), a quantitative evaluation of alpha-smooth muscle actin (ASMA) in glomeruli has been performed on human renal biopsies from patients suffering from acute, postinfectious, endocapillary glomerulonephritis (GN; 9 biopsies), IgA nephropathy (11 biopsies) and membranoproliferative GN (11 biopsies) and appropriate controls expressing a very weak ASMA reactivity. A significantly increased expression was found in all categories of GN. The glomeruli from IgA nephropathy showed variation of ASMA expression (range 0.1-27.7%) and a pattern of ASMA staining that was mesangial, global and diffuse. This pattern was also seen in cases of IgA nephropathy with focal, segmental, proliferative GN. In all biopsies, the glomerular cell number and proliferation index was determined. All the categories of GN showed significantly increased glomerular cellularity and proliferation index. Among the three types of GN, the glomerular cellularity and proliferation was lowest in IgA nephropathy. The mean number of Ki-67-positive intraglomerular nuclei and the proliferation index were both significantly correlated with the mean number of glomerular cell nuclei. Morphometric estimates demonstrate increased ASMA expression in types of GN with different prognosis. This finding and the lack of correlation with proliferation markers together indicate that the role of ASMA in GN is complex. This method of ASMA estimation may be useful in further studies of its role in disease activity and prognosis.