[Comparison of the efficiency of surgical excision methods for detecting extraprostatic extension and positive resection margin in prostate cancer]. / Sravnenie effektivnosti metodov vyrezki operatsionnogo materiala dlya vyyavleniya ekstraprostaticheskogo rasprostraneniya i polozhitel'nogo kraya rezektsii pri rake prostaty.

On the samples of 26 prostatectomies, the method of excision of the prostate gland according to Kim was tested. This method increased the number of blocks by 30.2% and increased the detectability of extraprostatic extension by 41.7% and positive surgical margin by 40.0% compared to the method of alternate prostate sections. Also, the method according to Kim reduced the number of blocks of prostate tissue by 34.3% compared to the method of complete prostate excision.

[Morphological precursors of high-grade serous ovarian cancer]. / Morfologicheskie predshestvenniki seroznogo raka yaichnikov vysokoi stepeni zlokachestvennosti.

At the beginning of this century, there was a paradigm shift in understanding the histogenesis of high-grade serous carcinomas. The theory of the origin of these tumors from the ovarian surface epithelium was replaced by the concept of their origin from the secretory epithelium of the fallopian tubes. In recent years, researchers have put forward the hypothesis of the "escape" of the precursor of high-grade serous carcinomas. It allows looking at the carcinogenesis of these neoplasms as a natural history of tumor transformation of the serous epithelium without reference to a specific localization.

Stimulation of Structural and Functional Recovery of the Kidney in Rats with Postischemic Acute Renal Failure of Different Severity by Embryonic Protein-Peptide Complex Therapy.

In male rats, acute renal failure was simulated by clamping the vascular pedicle of the left kidney for 60 or 90 min and right-sided nephrectomy. In the control series, no therapy was performed. In the experimental series, the animals were daily injected subcutaneously with Cellex, a protein-peptide complex (PPC) chromatographically isolated from the brain tissue of pig embryos with a molecular weight of its components from 10 to 250 kDa. PPC was administered 5 times a week (10 injections) in a dose of 0.1 ml/kg (0.1 mg active substance per 1 kg body weight). Ischemia of a single kidney led to the development of acute renal failure, more severe after 90-min ischemia. PPC therapy reduced the severity of functional disorders mainly at the early stages (3 and 7 days) with normalization of blood concentrations of urea and creatinine, creatinine clearance, tubular reabsorption of sodium and calcium, including the cases with 90-min ischemia, which did not occur in the control series. PPC therapy also contributed to hypertrophy of many glomeruli, prevented the development of glomerulosclerosis, and reduced damage to the epithelium of the renal tubules. At the same time, neither pronounced lymphohistiocytic infiltration, nor focal nephrosclerosis typical of control series were observed.

[The incidence of AZF deletions, CFTR mutations and long alleles of the ar CAG repeats during the primary laboratory diagnostics in a heterogeneous group of infertily men].

AIM: microdeletions in the AZF region of Y-chromosome, compound heterozygotes of severe and mild CFTR mutations, and long CAG-repeats in the androgen receptor gene (AR) as marker of predisposition are frequently studied as genetic causes of male infertility. A simultaneously testing of the panel including biochemical, immunological, cyto- and molecular genetic markers is often performed during the complex laboratory diagnostics in infertile men. The aim of our work was to identify molecular genetic alterations, which are advisable for simultaneously testing in a man with currently uncertain form of infertility, to increase the informativeness of laboratory diagnostics. MATERIALS AND METHODS: a retrospective study of 885 infertile men was conducted. AZF deletions were determined by multiplex PCR using 10 STS-markers (sY83, sY84, sY86, sY127, sY134, sY143, sY152, sY157, sY254, sY255) and two control loci SRY and AMEL with detection in polyacrylamide gel. Mutations in the CFTR gene (F508del, CFTRdel2.3(21kb), I507del, 1677delTA, 2143delT, 2184insA, 394delTT, W1282X, G542X, N1303K, R334W and 5T) were detected by PCR and SNaPshot. For determination of length of the AR CAG-repeat a fragment analysis of fluorescently labeled PCR products on the 3500xl capillary sequencer was performed. RESULTS: AZF deletions were detected in 8.2% of cases. The largest number of deletions was found in the AZFc subregion (58.9%), while a frequency of deletion in AZFa, AZFb or combined deletions of two and three subregions was 5.5%, 12.3% and 23.3%, respectively. Heterozygous carriage of severe CFTR mutations was detected in 4.7% patients. The most frequent mutation was F508del (83.3%), followed by CFTRdel21kb (7.1%) and W1282X (4.8%). The frequency of the mild splicing 5T mutation was 5.3%, and its incidence was significantly higher than in the previously published control group (p=0.002). AR genotyping revealed that the most prevailing allele was 21 (CAG) (21.5%). Long alleles with 27 or more CAG-trinucleotides were identified in 7.5% of the tested cases. In addition, 7 CAG heterozygotes with Kleinfelter syndrome were found. CONCLUSION: during primary complex laboratory diagnostics in a heterogeneous group of infertile men, it is advisable to detect AZF deletions and the most frequent CFTR mutations, including F508del, CFTRdel21kb, 1677delTA, 2143delT, W1282X and 5T. The more comprehensive analysis of CFTR mutations is justified only in patients with verified obstructive infertility. Sequencing of panels associated with infertility genes using NGS technology is promising.

Stimulation of Spermatogenesis and Synthesis of Testosterone by Allotransplantation of Neonatal Testicular Tissue under Tunica Albuginea of Cryptorchid Testis.

The abdominal type of cryptorchism was modeled on random-bred albino rats by replacing both testes from the scrotum into the abdominal cavity for 3 weeks; thereupon they were manipulated into the scrotum. In control rats, no additional surgery was performed. In experimental rats, the testicular tissue obtained from 1-2-day rat pups was transplanted under testicular tunica albuginea. Prior to orchiopexy, the weight of testes decreased by 62.5-64.1%. In 6 month after the surgery, it increased by 36.1% in the control group, whereas in experimental rats the weight of testes elevated by 123.2% and approximated the normal value. Histologically, the control group demonstrated persistent disturbance in spermatogenesis with emptiness of numerous seminiferous tubules where only Sertoli cells could be revealed and with pronounced dystrophic alterations in the spermatogenous epithelium of the partially preserved tubules where spermatogenesis was blocked at the spermatogonial level. In contrast, the transplantation region of the experimental testes exhibited formation of novel mature testicular tissue enclosed by a connective tissue capsule incorporating the seminiferous tubules with differentiated epithelium and with the clusters of Leydig cells in the stroma. In 6 month, spermatogenesis was observed in most seminiferous tubules of the host testicular tissue, which had spermatozoa in the lumens. To the moment of orchiopexy, the blood testosterone decreased by about 2.5-fold. In control group it remained diminished during entire observation period (up to 6 month), while in the experiment group its level normalized completely as early as in 2 month and remained even elevated to the end of observation period.

Ectopic Organogenesis after Allotransplantation of Freshly Removed or Cryopreserved Neonatal Testicle under the Renal Capsule in Rats.

In experiments on white outbred male rats, a freshly removed (20 experiments) or cryopreserved (10 experiments) testicle from newborn rats (1-2 days after birth) was transplanted under the renal capsule after bilateral orchiectomy. In all experiments with transplantation of freshly removed testicle, it was engrafted. In 3 months, histological examination revealed the formation of mature seminiferous tubules, but spermatogenesis was blocked at the stage of spermatogonia; groups of proliferating Leydig cells in the loose connective tissue between the tubules were also seen. In 6 and 12 months, the status of the seminiferous tubules remained unchanged, but structures typical of the epididymis and developing vas deferens were revealed. The number of proliferating Leydig cells increased. The initially low testosterone concentration in the blood of castrated males increased significantly as soon as in 1 month after transplantation and grew up to 3 months, remaining at a level ~50% of normal. Engraftment of cryopreserved neonatal testicular tissue was observed in 60% cases, however, engrafted tissue, similar to the fresh one, retained the ability for organogenesis with the formation of mature seminiferous tubules, epididymis, and groups of proliferating Leydig cells. The dynamics of blood testosterone concentration in rats with cryopreserved and fresh transplantation was similar. Subcapsular transplantation did not adversely affect the kidneys, which was seen from normal histological structure of the kidneys and creatinine and urea concentrations in the blood.

[The development and approbation of methodology on the basis of multiplex polymerase chain reaction in real-time to determine clinically significant micro-deletion in Y-chromosome.]

One of the prevalent genetic causes of idiopathic male sterility is related to micro-deletions in AZF locus located in Y-chromosome. In total population, rate of such micro-deletions makes up to 1:4000. however, in infertile males their rate varies from 2% to 10%. In AZF locus three subregions are distinguished: AZFa, AZFb and AZFc. The loss of one or several subregions can result in disorder of spermatogenesis of various degree - from decreasing of its activity to Sertoli-cell syndrome manifested by azoospermia or oligospermia of severe degree. Therefore, implementation of genetic testing for presence of micro-deletions in AZF locus is a necessary test in case of prognosis of male sterility and its treatment. The purpose of study is to develop and test a diagnostic system of detection of micro-deletions in subregions of AZF locus using multiplex polymerase chain reaction in real-time. As a reference method a technique was implemented described in guidelines of the European Academy of Andrology conjointly with European Molecular Genetics Quality Network. The technique testing specified analysis of 33 samples of DNA separated from blood of males with azoospermia and oligospermia of severe degree. No discordant results were received as compared with reference method. In 27 DNA samples the deletions were detected in AZF locus: 4 AZFa deletions (15%), 2 AZFb deletions (7%), 17 AZFc deletions (63%) and 6 combined deletions of AZFb+candи AZFa+b+с (22%). The proposed technique permits detect micro-deletions of subregions of AZF locus.

Detection of Rare Mutations by Routine Analysis of KRAS, NRAS, and BRAF Oncogenes.

Molecular genetic analysis of KRAS, NRAS, and BRAF genes was carried out in order to develop an optimal algorithm for detection of minor mutations. We analyzed 35 melanoma and 33 colorectal cancer specimens. Frequent G12D/V/A/C/S mutations were detected in KRAS. The most frequent BRAF mutation in melanoma was V600E, the percentage of rare mutations is significant for DNA diagnosis (24%). Identification of rare BRAF mutations 1790C→G (L597R), 1798_1799delinsAA (V600K), 1798_1799delinsAG (V600R), and 1799_1800delinsAA (V600E) and NRAS mutation 38G→T (G13V) was possible only by Sanger sequencing. The combination of real-time PCR and sequencing can improve analysis sensitivity and ensure concordance of the tested loci with the international recommendations.

[A new WHO classification of prostate tumors]. / Novaya klassifikatsiya VOZ opukholei predstatel'noi zhelezy.

The paper reviews the 2016 WHO classification of prostate tumors, notes the alterations made, and describes approaches to the diagnosis of cancer types and grades. It also gives original photomicrographs from the authors' collection. The main alterations were as follows: - The types of prostate adenocarcinoma were added by pleomorphic giant-cell carcinoma; oncocytic (8290/3) and lymphoepithelial (8082/3) carcinomas were excluded. - Grade III prostatic intraepithelial neoplasia (PIN) was substituted for high grade PIN (8148/2). - Intraductal carcinoma (8500/2) was added. - Basal cell adenoma (8147/0) was excluded. - Carcinoids were referred to as low-grade neuroendocrine tumors according to the current terminology; large cell neuroendocrine cancer (8013/3) was added. - Paraganglioma (8613/3) and neuroblastoma (9500/3) were excluded. Stromal tumors were grouped with mesenchymal neoplasms. -Malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor, chondroma, and hemangiopericytoma were excluded. - Synovial sarcoma (9040/3), inflammatory myofibroblastic tumor (8825/1), osteosarcoma (9180/3), undifferentiated pleomorphic sarcoma (8802/3), solitary fibrous tumor (8815/1), and malignant solitary fibrous tumor (8815/3) were added. The section of lymphoproliferative diseases was extended. The tumors of unknown origin included paraganglioma and neuroblastoma from a group of neuroendocrine tumors. The TNM staging was completely consistent with the 2010 AJCC version.

[Hormone Resistance and Neuroendocrine Differentiation Due to Accumulation of Genetic Lesions during Clonal Evolution of Prostate Cancer].

Progression of malignant tumors is largely due to clonal evolution of the primary tumor, clones acquiring different sets of molecular genetic lesions. Lesions can confer a selective advantage in proliferation rate or metastasis on the tumor cell population, especially if developing resistance to anticancer therapy. Prostate cancer (PCa) provides an illustrative example of clinically significant clonal evolution. The review considers the genetic alterations that occur in primary PCa and the mechanism whereby hormone-refractory PCa develops on hormone therapy, including mutations and alternative splicing of the androgen receptor gene (AR) and intratumoral androgen synthesis. Certain molecular genetic lesions determine resistance to new generation inhibitors (AR mutations that block the antagonist effect or allow other hormones to activate the receptor) or lead to neuroendocrine differentiation (repression of the AR signaling pathway, TP53 mutations, and amplification of the AURKA or MYCN oncogene). Multistep therapy based on the data about somatic mutations associated with progression and metastasis of the primary tumor can be expected to significantly improve the survival of patients with advanced PCa in the nearest future.

Ischemia in pelvic organs as an independent pathogenic factor in the development of benign prostatic hyperplasia and urinary bladder dysfunction.

Blood supply to the pelvic organs of outbred male rats was diminished by graduated constriction of the distal part of the inferior vena cava. Deficiency of intramural blood supply in prostate and urinary bladder was revealed by bioimpedance harmonic analysis according to the magnitude of first cardiac peak in the bioimpedance spectrogram. In 1-1.5 months, the histological examination revealed the glandular-stromal form of progressive benign prostatic hyperplasia in all ischemic rats. The development of hyperplasia was not accompanied by the changes in testosterone, dihydrotestosterone, or estradiol in blood and prostatic tissue. Assessment of vesical functional status by recording the intravesical pressure during infusion cystometry revealed an increase in the amplitude of spontaneous fluctuations of detrusor tone and intravesical pressure during bladder filling, which can be considered as indicator of detrusor hyperactivity. The data conclude that chronic ischemia of pelvic organs is an individual pathogenic factor in the development of benign prostatic hyperplasia and associated urinary disorders.

[PCA3 AND TMPRSS2:ERG GENES EXPRESSION IN BIOPSIES OF BENIGN PROSTATE HYPERPLASIA, INTRAEPITHELIAL NEOPLASIA, AND PROSTATE CANCER].

Morphological analysis of the biopsies for prostate cancer (PCa) often is a difficult task due to heterogeneity and multifocality of tumors. At the same time, a lot of data exist about the potential molecular genetic markers of PCa. The aim of our study is to determine of PCA3 and TMPRSS2:ERG genes expression in benign hyperplasia (BPH), low and high grade intraepithelial neoplasia (PIN), PCa for revealing of diagnostic value of those genes expression in benign and precancerous changes in prostate. Total RNA was isolated from 53 biopsies, reverse transcription was performed, gene expression was determined by real time PCR (RT-PCR) then deltaCt index was determined as Ct(PCA3)--Ct(KLK3). Average deltaCt and its SD in BPH were 8.28 ± 3.13, low PIN--8.56 ± 2.64, high PIN--8.98 ±1.69, PCa--1.08 ± 2.36. We have demonstarted that deltaCt did not differ in patients with BPH, low and high grade PIN, whereas significantly increased in PCa relative to any of the three groups listed above (p < 0.0001). Expression of TMPRSS2:ERG was absent in BPH, PIN, but it was detected in 40% (4/10) of PCa cases. ROC-analysis showed that the AUC (area under ROC-curve with 95% CI, p < 0.0001) was 0.98 ± 0.02 in the analysis of a combination of overexpression of PCA3 and TMPRSS2:ERG. Thus, the expression analysis of the PCA3 and chimeric oncogene TMPRSS2:ERG in biopsy cannot be used for differential diagnosis of BPH, low and high grade PIN. However, overexpression of PCA3 and expression of TMPRSS2:ERG are characteristic in PCa. Expression analysis of these genes by the proposed RT-PCR modification at the threshold level deltaCt 3,22 has diagnostic accuracy 90% to detect PCa in biopsy specimens.

[Markers for non-invasive molecular genetic diagnosis of oncourological diseases].

Currently, there is accumulated mass of data on the molecular-genetic disorders in prostate cancer (PCa), bladder cancer (BC) and renal cancer (RC). Tumor cells in these diseases are present in the urine sediment; their number is sufficient for molecular genetic analysis that makes possible the development of noninvasive diagnosis of oncourological diseases. A characteristic feature of PCa includes the overexpression of the PCA3 gene; assay kit Progensa™ to quantify such overexpression has been developed; approximately 50% of tumors express a TMPRSS2-ERG chimeric oncogene. Combined analysis of PCA3 and TMPRSS2-ERG allows to detect PCa with a diagnostic accuracy of 84%, which is significantly higher than that of prostate specific antigen test. As a potential markers of BC, there are somatic mutations in FGFR3, PIK3CA, TERT genes in urine sediment, which are found in this disease with a frequency of about 60, 30 and 50%, respectively. The basis of the test system for DNA diagnosis of BC in urine sediment may include a definition of a combination of mutations in these genes with microsatellite instability. Aberrant methylation of the 5'-regulatory regions of tumor suppressor genes, integrated in the panel, also is considered as a tool in the diagnosis of RC (VHL, RASSF1, RARB2, CDH1), PCa (GSTP1, PTGS2, LGALS3) and BC (RASSF1, APC, SFRP2) after standardization of panels of loci investigated, sample preparation methods, bisulfite conversion, and the design of primers and probes. Thus, a test systems for molecular genetic diagnosis of oncourological diseases in urine sediment are currently available or may be developed in the near future.

Proteomic analysis of infiltrating ductal carcinoma tissues by coupled 2-D DIGE/MS/MS analysis.

There is a growing interest in protein expression profiling aiming to identify novel diagnostic markers in breast cancer. Proteomic approaches such as two-dimensional differential gel electrophoresis coupled with tandem mass spectrometry analysis (2-D DIGE/MS/MS) have been used successfully for the identification of candidate biomarkers for screening, diagnosis, prognosis and monitoring of treatment response in various types of cancer. Identifying previously unknown proteins of potential clinical relevance will ultimately help in reaching effective ways to manage the disease. We analyzed breast cancer tissues from five tumor and five normal tissue samples from ten breast cancer subjects with infiltrating ductal carcinoma (IDC) by 2-D DIGE using two types of immobilized pH gradient (IPG) strips: pH 3-10 and pH 4-7. From all the spots detected, differentially expressed (p < 0.05 and ratio > 2) were 50 spots. Of these, 39 proteins were successfully identified by MS, representing 29 different proteins. Ten proteins were overexpressed in the tumor samples. The 2-D DIGE/MS/MS analysis revealed an increase in the expression levels in tumor samples of several proteins not previously associated with breast cancer, such as: macrophage-capping protein (CAPG), phosphomannomutase 2 (PMM2), ATPase ASN1, methylthioribose-1-phosphate isomerase (MRI1), peptidyl-prolyl cis-trans isomerase FKBP4, cellular retinoic acid-binding protein 2 (CRABP2), lamin B1 and keratin, type II cytoskeletal 8 (KRT8). Ingenuity Pathway Analysis (IPA) revealed highly significant (p = 10(-26)) interactions between the identified proteins and their association with cancer. These proteins are involved in many diverse pathways and have established roles in cellular metabolism. It remains the goal of future work to test the suitability of the identified proteins in samples of larger and independent patient groups.

Microbiological and chemical characteristics of water and sediment from Vrelo Cave, Republic of Macedonia.

Vrelo Cave is the deepest cave in Macedonia, located in the canyon Matka which is home to many endemic species not found anywhere else in Europe. Until now, Vrelo Cave has not been investigated in terms of its composition and biodiversity. The purpose of this study was to offer some preliminary data for physical and chemical parameters of water and sediments from Vrelo Cave, as well as its microbiological diversity. Samples were taken from 5 locations. They were analysed for a wide array of physico-chemical parameters, macro- and microelements and concentration of selected organic pollutants. All samples were investigated for several groups of bacteria, yeasts and moulds by a conventional selective media approach. Molecular identification of the isolated bacterial species was done by sequencing of the bacterial 16S ribosomal RNA gene. Regarding the total dry components, total hardness, dissolved oxygen, biochemical and chemical consumption of oxygen, water from Vrelo Cave belongs to Class I. All of the investigated groups of microorganisms except anaerobic sporogenic bacteria were present in water and sediment samples. Notably, a large number of coliformic bacteria (total and faecal) were isolated from all of the investigated samples which classify this water in Class IV, as ecologically unsuitable drinking water. Most of the identified non-coliformic bacteria belonged to the genus Bacillus. We have also identified representatives from Staphylococcus, Proteus, Brevundimonas and Enterobacter. Overall findings suggest a possible connection between the water from the cave and surface waters. Further investigation should be performed to determine the origin of these waters.

A new thermostable DNA polymerase mixture for efficient amplification of long DNA fragments.

The thermostable DNA polymerases have been used for amplification of DNA fragments since the invention of PCR. The constraint on the maximum size of the amplified fragments can be solved to certain level by the use of unbalanced mixtures of non-proofreading and proofreading thermostable DNA polymerases. In this study, we tested the use of a mixtures of N-terminal deletional variant of Taq polymerase - Klentaq278 and Tne polymerase from Thermotoga neapolitana. Klentaq278 and Tne polymerase genes were cloned and expressed in different expression vectors under tac promoter. The most efficient ratio of Klentaq278/Tne polymerase for amplification was 10 : 1. The polymerase mixture of Klentaq278 and Tne polymerase is very effective in amplification of DNA fragments for up to 8 kb and is useful addition to a DNA polymerases used in long-range PCR.

Hb Jambol: a new hyperunstable hemoglobin causing severe hemolytic anemia.

We describe a new hyperunstable beta-chain variant due to a complex genomic rearrangement. The abnormal hemoglobin (Hb) was found as a de novo mutation in a 2-year-old Bulgarian girl with severe hemolytic anemia. The mutation was detected through RNA/DNA analysis. It represents a complex genomic rearrangement involving an insertion of 23 nts after IVS-II-535 (derived by triplication of the 12-nts adjacent sequence and subsequent deletion of 1 nt), a deletion of 310 nts extending from IVS-II-550 to the first nt of Cd 108 and an insertion of 28 nts at the deletion junctions (derived from the inverted sequence between nts +3,707 and +3,734 3' to the beta-globin gene termination codon). At the protein level this mutation leads to a deletion of 4 amino acid residues (Leu-Leu-Glu-Asn) at positions 105-108 and an insertion of 9 residues (Val-Pro-Ser-Val-Thr-Leu-Phe-Phe-Asp) at the same location, creating an abnormal elongated beta-chain of 151 amino acid residues. This highly unstable variant was named 'Hb Jambol' after the geographic location in which the patient resides.

Level of nitric oxide in hypertensive patients scheduled on general anaesthesia.

In this prospective study we have analysed the level of nitric oxide in hypertensive patients scheduled for general anaesthesia. In the study were included thirty-four patients with chronicle inflammatory disease of the middle ear who have undergone surgical treatment at the Clinic for Ear, Nose and Throat Surgery. The aim of our study was to determine the plasma level of nitric oxide (NO) and its effects on the circulatory system in hypertensive patients during the general anaesthesia maintained with inhalation of oxygen and nitrous oxide (O2/N2O) mixture. Patients were divided in two groups. During the maintenance of general anaesthesia the patients from the first group were ventilated with O2/N2O, while patients from the second group were ventilated with oxygen and air (O2/air) mixture. The other principles during the general anaesthesia were equal for both groups. For determination of the NO plasma levels we have used the enzymatic method according to Conrad et al., 1993. Our results showed that there is a statistically significant difference of NO plasma level between the two groups. The level of NO was higher in the first group (ventilated with O2/N2O) compared to the second group (ventilated with O/air). The mean arterial pressure and systemic vascular resistance were significantly decreased in the first group, as well. Our results suggest that nitrous oxide (N2O) most probably plays the role of NO donor in hypertensive patients during the maintenance of the general anaesthesia with N2O/O2 mixture.

Reverse transcriptase/polymerase chain reaction analyses of hemodialysis ultrafiltrates and sera of hepatitis C virus positive patients.

The hepatitis C virus is a highly prevalent infection among chronic dialysis patients and represents one of the major problems of hemodialysis units. Hepatitis C virus transmission occurs either by blood transfusion or nosocomially. One of the proposed pathways of nosocomial transmission of the hepatitis C virus is cross-contamination through the dialysis procedure. In an effort to elucidate whether the hepatitis C virus may pass across the hemodialysis membrane, we have performed analyses of ultrafiltrates collected in different stages of hemodialysis treatments, using different types of hemodialysis membranes and different types of dialysis machines. Samples collected from the dialysis compartment during the rinsing of the blood compartment at the end of the hemodialysis treatment were also analyzed. The hepatitis C virus was found in 17 out of 58 ultrafiltrate samples taken at different times of the hemodialysis treatment. Moreover, the hepatitis C virus was present in 15 out of 17 samples collected from the dialysate compartment during the saline solution rinsing step of the blood compartment. The presence of the hepatitis C virus had no strict correlation with the type of dialysis membrane or with the type of dialysis machine. Although the results suggest that the passage of the hepatitis C virus during the hemodialysis treatment is multi-factorial and case- specific, the most critical point is when the blood is flushed out with physiological saline.