Stem/progenitor cells in fetuses and newborns: overview of immunohistochemical markers

Microanatomy of the vast majority of human organs at birth is characterized by marked differences as compared to adult organs, regarding their architecture and the cell types detectable at histology. In preterm neonates, these differences are even more evident, due to the lower level of organ maturation and to ongoing cell differentiation. One of the most remarkable finding in preterm tissues is the presence of huge amounts of stem/progenitor cells in multiple organs, including kidney, brain, heart, adrenals, and lungs. In other organs, such as liver, the completely different burden of cell types in preterm infants is mainly related to the different function of the liver during gestation, mainly focused on hematopoiesis, a function that is taken by bone marrow after birth. Our preliminary studies showed that the antigens expressed by stem/progenitors differ significantly from one organ to the next. Moreover, within each developing human tissue, reactivity for different stem cell markers also changes during gestation, according with the multiple differentiation steps encountered by each progenitor during development. A better knowledge of stem/progenitor cells of preterms will allow neonatologists to boost preterm organ maturation, favoring the differentiation of the multiple cells types that characterize each organ in at term neonates.

Comparison of cryoprotective methods for histological examination of rat and porcine lung tissue

Proper histological evaluation of lung tissue and accurate antigen detection by immunodetection techniques require histological tissue processing to preserve tissue reactivity and open alveolar spaces. In this study, we focused on testing and comparing different procedures of tissue cryopreservation. Sucrose or Tissue Tek were used with several methods of freezing samples by supercooled liquids and liquid nitrogen. Changes in tissue caused during the freezing of samples and the effect of cryoprotectants on the tissue were recorded. Rat and porcine pulmonary tissues were used in this experiment. This study aimed to optimize the process of lung cryopreservation with emphasis on enabling proper anatomical evaluation and preserving a high tissue immunoreactivity. The best results were obtained by inflating pulmonary parenchyma with a 1 : 1 mixture of O.C.T. with phosphate buffered saline (PBS) frozen in supercooled n-heptane placed on dry ice. Pulmonary tissue prepared in this way enables to perform proper histological evaluation and to detect target molecules by immunohistochemical analysis.

Membranous nephropathy in patients with HIV: a report of 11 cases

Background Membranous nephropathy (MN) has been recognized to occur in patients with human immunodeficiency virus (HIV) infection since the beginning of the HIV epidemic. The prevalence of phospholipase A2 receptor (PLA2R)-associated MN in this group has not been well studied. Methods We conducted a retrospective review of electronic pathology databases at three institutions to identify patients with MN and known HIV at the time of renal biopsy. Patients with comorbidities and coinfections known to be independently associated with MN were excluded. Results We identified 11 HIV-positive patients with biopsy-confirmed MN meeting inclusion and exclusion criteria. Patient ages ranged from 39 to 66 years old, and 10 of 11 patients (91%) were male. The majority of patients presented with nephrotic-range proteinuria, were on anti-retroviral therapy at the time of biopsy and had low or undetectable HIV viral loads. Biopsies from 5 of 10 (50%) patients demonstrated capillary wall staining for PLA2R. Measurement of serum anti-PLA2R antibodies was performed in three patients, one of whom had positive anti-PLA2R antibody titers. Follow-up data was available on 10 of 11 patients (median length of follow-up: 44 months; range: 4–145 months). All patients were maintained on anti-retroviral therapy (ARV) and 5 patients (52%) received concomitant immunosuppressive regimens. Three patients developed end-stage renal disease (ESRD) during the follow-up period. Conclusions MN in the setting of HIV is often identified in the setting of an undetectable viral loads, and similar to other chronic viral infection-associated MNs, ~ 50% of cases demonstrate tissue reactivity with PLA2R antigen, which may be seen without corresponding anti-PLA2R serum antibodies.

Sutureless Wound Closure- Our Experience

Traditional techniques for wound closure are- Sutures (stitches), staples and adhesive tapes. Tissue adhesives have entered clinical practice more recently. Sutures enable the closure of the wound to be meticulous, but they have drawbacks. Sutures may show tissue reactivity and can require removal

Potential Roles of CD34+ Fibrocytes Masquerading as Orbital Fibroblasts in Thyroid-Associated Ophthalmopathy

Context Orbital tissues in thyroid-associated ophthalmopathy exhibit particular reactivity and undergo characteristic remodeling. Mechanisms underlying these changes have remained largely unexplained. Studies have characterized orbital connective tissues and derivative fibroblasts to gain insights into local manifestations of a systemic autoimmune syndrome. Evidence Acquisition A systematic search of PubMed was undertaken for studies related to thyroid-associated ophthalmopathy (TAO), orbital fibroblasts, and fibrocytes involved in pathogenesis. Evidence Synthesis Orbital tissues display marked cellular heterogeneity. Fibroblast subsets, putatively derived from multiple precursors, inhabit the orbit in TAO. Among them are cells displaying the CD34+CXC chemokine receptor 4+collagen I+ phenotype, identifying them as fibrocytes, derived from the monocyte lineage. Their unique presence in the TAO orbit helps explain the tissue reactivity and characteristic remodeling that occurs in the disease. Their unanticipated expression of several proteins traditionally thought to be thyroid gland specific, including the TSH receptor and thyroglobulin, may underlie orbital involvement in Graves disease. Although no currently available information unambiguously establishes that CD34+ orbital fibroblasts originate from circulating fibrocytes, inferences from animal models of lung disease suggest that they derive from bone marrow. Further studies are necessary to determine whether fibrocyte abundance and activity in the orbit determine the clinical behavior of TAO. Conclusion Evidence supports a role for fibrocytes in the pathogenesis of TAO. Recognition of their presence in the orbit now allows development of therapies specifically targeting these cells that ultimately could allow the restoration of immune tolerance within the orbit and perhaps systemically.

Ιδιότητες των ραμμάτων που χρησιμοποιούνται στην κτηνιατρική χειρουργική

Sutures are necessary for wound healing in surgery and for ligation of vessels. Many of sutures currently available are classified according to their characteristics, such as the tensile strength, the elasticity, the plasticity, the pliability, the knot security, the memory, the capillarity, the tissue drag and the tissue reactivity. Regarding the rate of reduction of tensile strength, sutures are widely classified as absorbable, used in tissue closure that do not require long-term support, and non-absorbable, used whenever prolonged mechanical support is required. Sutures are also classified as natural or synthetic, as well as monofilament or multifilament depending on origin or structure, respectively. Sutures are available in different sizes. As suture’s size increases, increase in the tensile strength also occurs. Absorbablesutures described in this review include catgut, polydioxanone, polyglyconate, glycomer 631, polyglycolic acid, polyglactin 910, poliglecaprone 25,polyglytone 6211 and lactomer 9-1. Non-absorbable sutures described in this review include surgical silk, cotton, nylon,polymerised caprolactam, polyester fibers, polybutester, polypropylene and stainless steel. Usually, sutures are attached to surgical needles creating a continuous unit. Needles are classified based on their shape, length, way of suture attachment and cross-section of body and point. The latter property divides needles into blunt, taper and cutting; the selection of the appropriate type is based on the tissue that has to be sutured. Sutures in modern veterinary surgery are usually available in disposable sterilized packages.