Spotlight on the three main hepatic fibrogenic cells in HCV-infected patients: Multiple immunofluorescence and ultrastructure study.

The present work deals with the simultaneous ultrastructure and triple immunofluorescence study of the three main hepatic fibrogenic cells, hepatic stellate cell, myofibroblast (MF), and fibroblast, in a group of hepatitis C virus (HCV) RNA positive patients, as their exact interrelation behavior in vivo with the progress of hepatic fibrosis is still inadequate. In this study, for the first time, cells having the morphological characteristic of MF and not bone marrow fibrocytes were revealed in liver portal vessels. This necessitates the reevaluation of the available knowledge concerning bone marrow fibrocyte. Also, the distribution, cellular interrelations, and the fate of MF were highlighted.

EFFECT OF LINEZOLID ALONE AND IN COMBINATION WITH OTHER ANTIBIOTICS, ON METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS.

The prevalence of methicillin-resistant Staphyloccoccus aureus (MRSA) strains has presented a new challenge in antimicrobial medication. Linezolid is a new drug with potent activity on Gram-positive pathogens such as MRSA. The aim of the study was to investigate the in vitro activity of linezolid alone and in combination with imipenem, vancomycin or rifampicin to determine the most active therapy against MRSA strains. Twenty clinical MRSA strains were isolated from patients admitted to inpatient departments and outpatient clinics of Theodor Bilharz Research Institute. Standard strain MRSA ATCC 43300 was included as a control. The MICs of MRSA strains to linezolid, vancomycin, imipenem and rifampicin were evaluated using E test. Time-kill curve were used to assess the in vitro activity of linezolid (at 8x MIC) alone and in combination with imipenem (at 32x MIC), vancomycin or rifampicin (at 8x MIC). Scanning and transmission electron microscopy were performed to compare bacterial morphological alterations owing to the different combi- nations. Time-kill studies showed synergistic effect when linezolid combined with imipenem was tested against all the MRSA strains. Linezolid plus vancomycin or rifampicin combinations did not display any synergism or antagonism. Scanning and transmission electron microscopy observations confirmed the interactions observed in time kill experiments. Linezolid in combination with subinhibitory concentrations of imipenem can be bactericidal against MRSA strains and appears to be a promising combination for the treatment of MRSA infections. No synergistic activity was seen when the linezolid and vancomycin or rifampicin were combined. Linezolid could prevent the emergence of mutants resistant to rifampicin

CD133(+) human umbilical cord blood stem cells enhance angiogenesis in experimental chronic hepatic fibrosis.

The in vivo angiogenic potential of transplanted human umbilical cord blood (UCB) CD133(+) stem cells in experimental chronic hepatic fibrosis induced by murine schistosomiasis was studied. Enriched cord blood-derived CD133(+) cells were cultured in primary medium for 3 weeks. Twenty-two weeks post-Schistosomiasis infection in mice, after reaching the chronic hepatic fibrotic stage, transplantation of stem cells was performed and mice were sacrificed 3 weeks later. Histopathology and electron microscopy showed an increase in newly formed blood vessels and a decrease in the fibrosis known for this stage of the disease. By immunohistochemical analysis the newly formed blood vessels showed positive expression of the human-specific angiogenic markers CD31, CD34 and von Willebrand factor. Few hepatocyte-like polygonal cells showed positive expression of human vascular endothelial growth factor and inducible nitric oxide synthase. The transplanted CD133(+) human stem cells primarily enhanced hepatic angiogenesis and neovascularization and contributed to repair in a paracrine manner by creating a permissive environment that enabled proliferation and survival of damaged cells rather than by direct differentiation to hepatocytes. A dual advantage of CD133(+) cell therapy in hepatic disease is suggested based on its capability of hematopoietic and endothelial differentiation.

Homing of transplanted bone marrow cells in livers of Schistosoma mansoni-infected mice.

The efficiency of differentiation of bone marrow cells (BMCs) into hepatocytes in vivo and its importance in physiopathological processes is still debated. Murine schistosomiasis was used as a liver injury model and unfractionated male mice BMCs were transplanted through intrahepatic injection into non-irradiated Schistosoma mansoni-infected female mice on their 16th week post-infection. Two weeks after bone marrow transplantation, mice were sacrificed on a weekly basis until 10 weeks. Tracing of male donor-derived cells in female recipient mice livers was carried out by the detection of Y chromosome expression by fluorescent in situ hybridization (FISH) and also of chromodomain Y-linked (CDYL) protein by indirect immunofluorescence (IF). Their transformation into hepatocytes was studied by double labelling indirect IF using antibodies directed against CDYL and mouse albumin. Histopathological and electron microscopic examinations revealed the presence of small hepatocyte-like cells in the periportal tracts and in between the hepatocytes facing the sinusoids. Donor-derived cells showing Y chromosome by FISH and expressing CDYL protein by IF were recovered in the infected transplanted livers. The initial number of these cells increased with increased post-transplantation time. Cells were mainly localized in the periphery of schistosoma granuloma. Few donor-derived cells appeared within the hepatic parenchymal tissue and showed positivity for albumin secretion by double labelling with IF. We suggest that transplanted bone marrow stem cells can repopulate the Schistosoma-infected liver of immunocompetent mice. Their differentiation is a complex event controlled by many factors and needs to be further characterized extensively. The extent and type of liver injury and the number of transplanted cells are important variables in the process of stem cell engraftment and differentiation into functioning hepatic cells that still need to be defined.

Hepatic stellate cells and fibrogenesis in hepatitis C virus infection: an ultrastructural insight.

An ultrastructural quantitative assessment of hepatic stellate cells (HSCs) was made in relation to hepatic fibrosis, apoptotic cellular changes, intracellular fat deposition, circulating inflammatory cells in the sinusoids, and the necroinflammatory activity in liver specimens of 33 patients proven to be positive for hepatitis C virus (HCV)-RNA by polymerase chain reaction with the intention that electron microscopy may throw more light on the role of HSCs in the complicated process of fibrogenesis. A detailed review concerning these parameters and observed evidence suggesting the potential properties of HSCs to recycle cellular debris into collagen fibers are reported.

Value of the innovated technique agarose cell block in improving the sensitivity of urine cytology in cases of bladder carcinoma.

Proper handling and processing of urine sample can greatly improve diagnostic sensitivity. This work investigates the value of agarose cell block technique in processing urine samples simultaneously for light and electron microscopic examination, with the prospect to enhance the quality of diagnosis. The material of this study consisted of 45 voided urine samples, processed for the performance of Papanicolaou-stained urine smears, agarose cell blocks paraffin sections stained with hematoxylin & eosin, and electron microscopy-contrasted ultrathin sections. The studied technique increases the sensitivity of urine cytology and opens a new prospect for cytomorphological study.