In December 2019 a newly described single-stranded coronavirus, later named SARS-CoV-2, started its expansion around the world and subsequently caused a global pandemic, affecting the lives of millions of people worldwide. SARS-CoV-2 can bind multiple receptors on different cells and thus invade many target organs, including the respiratory and gastrointestinal mucous membranes, lungs, central nervous system, heart, etc. This virus can affect the kidney tissue both directly and as a consequence of other organ involvement or of the treatment administered, causing acute kidney injury and leaving long term squeals that worsen the prognosis. We describe three patients with acute kidney injury and subsequent acute renal failure at the background of coronaviral infection.

Systemic lupus erythematosus is a chronic, systemic, non-organ-specific autoimmune disease that affects all organs and systems of the human body and is characterized by the production of autoantibodies against nuclear antigens. Its prevalence in Europe reaches 1:2500. It affects mostly women (female : male ratio=9 : 1) in fertile age group (15-45 years). The clinical course of lupus in males is characterized by more aggressive clinical course and the development of serious complications, such as vasculitis, central nervous system involvement, antiphospholipid syndrome, etc. For the period of 7 years (2012-2019) we observed overall 18 male patients with systemic lupus, 11 with biopsy-proven renal involvement and 7 without clinically significant renal disease (proteinuria < 0.5 g/24 h., no erythrocyturia/cylindruria, normal renal function), mean age at the diagnosis 39.6 +/- 12.3 years. All patients received pathogenetic treatment (corticosteroids + cytotoxic agents). Three had secondary antiphospholipid syndrome, 1 – inflammatory bowel disease, 1 – seronegative spondyloarthropathy. Three had type 2 diabetes. The authors discuss the clinical, immunological and histological characteristics and the therapeutic approach in males with systemic lupus.

Background: The diagnosis of chronic kidney disease (CKD) is usually delayed, when significant functional renal impairment has already occurred. The diagnosis is complex and clinical and laboratory investigations play a crucial role. There are well-established markers of CKD – serum creatinine and cystatin C. However, the search for new reliable biomarkers that aid in the assessment of kidney function and predict the evolution of the disease is still in progress. Objective: To investigate the role of serum uromodulin (sUmod) as a marker for early diagnosis of renal impairment in patients with CKD. Materials and Methods: We investigated 70 patients, 28 male and 42 female, mean age 56.53 ± 11.753, with CKD in a prospective observational study. All patients were admitted to the Clinic of Nephrology at the “St. Ivan Rilski” University Hospital between April and November 2019. After obtaining written informed consent, laboratory blood and urine tests, abdominal ultrasound and sUmod investigations were performed in all patients. Results: Plasma uromodulin levels showed decrease with the increasing of the severity of renal impairment. sUmod displayed inverse correlation with serum creatinine (r = -0.467, p < 0.0001), cystatin C (r = -0.430, p < 0.0001) and urea (r = -0.495, p < 0.0001) and a positive correlation with eGFR (r = 0.628, p < 0.0001). Conclusion: The results of our study show that sUmod levels significantly correlate with all established laboratory parameters used for the evaluation of renal impairment. It can be used as a potential early biomarker for CKD diagnosis.

Summary. Pre-analytical factors of variation need to be carefully considered and investigated in efforts to harmonize all aspects of the total testing process. This study aimed to evaluate contamination and stability in copper (Cu) analysis of serum and urine by fl ame atomic absorption spectroscopy (FAAS) and to compare the stability of urine Cu in controls and in D-penicillamine (D-PA) administration. Cu was measured by AAnalyst 400, Perkin Elmer, USA. Blood was collected in BD Vacutainer ® SSTTM II Advance tubes and BD Vacutainer ® Trace Element tubes. Sterile polyethylene and polypropylene vessels for collection, transportation, storage and preliminary preparation of samples were used in urinalysis. Stability in serum and 24 h urine was evaluated in two temperature regimens: 15-25°C and 2-8°C, for particular time of storage. No signifi cant differences (p = 0.20) in Cu concentration was found between the two types of tested tubes with patient`s sera. The stability of the samples (serum and urine) was better at refrigeration temperature. In urine the stability was better in D-PA administration.Standardization of Cu analysis could be achieved by assessing the aspects of pre-analytical factors of variations.

Copper (Cu) and zinc (Zn) are essential for life. Body Cu and Zn content depends on variety of factors -age, gender, and diet, type of drinking water, geographical location and genetic predisposition. Copper status becomes even more relevant not only in rare genetic disorders such as Wilson disease but in diseases such as cardiovascular ones, impaired glucose tolerance and neurodegenerative and tumor diseases. The study aimed to examine the distribution of serum Cu and Zn in a representative group of the Bulgarian population and to describe factors which infl uence metal content. It also aimed to describe the link between serum Cu levels and the frequency of Alzheimer's disease (AD) in Bulgarians. Cu and Zn in serum were measured in 379 individuals (172 males and 207 females) from 5 different regions in Bulgaria by fl ame atomic absorption using AAnalyst 400, Perkin Elmer. Statistical analyses were performed by SPSS, 19. Median and inert-quartile range (IQR) for blood Cu were 15.89 (13.87-7.89) μmol/L and for Zn -13.00 (11.7-14.68) μmol/L in the examined group. Higher Cu levels in females than in males were found (p < 0.001). Decrease of Zn with aging was established (p > 0.05). Signifi cant difference (p < 0.05) was found in serum Cu between young people (< 30 year old) and adults over 61 year old. Statistically signifi cant difference in Cu and Zn was observed (p < 0.05) in respect of residences. Difference without signifi cance was measured between serum lipids and serum Cu (p = 0.541) and Zn (p = 0.741).

Wilson's disease is an inherited autosomal recessive disorder of copper balance leading to accumulation of copper mainly in liver and