Dysregulated in vitro hematopoiesis, radiosensitivity, proliferation, and osteoblastogenesis with marrow from SAMP6 mice

The senescence accelerated-prone mouse variant 6 (SAMP6) shows normal growth followed by rapid aging, development of osteopenia, and shortened lifespan, compared with control R1 mice. Because oxidative stress is a fundamental mechanism of tissue aging, we tested whether cellular parameters that are associated with oxidative stress are impaired with marrow from SAMP6 mice. We compared in vitro hematopoiesis, irradiation sensitivity, proliferative potential, and osteoblastogenesis with marrow cells from SAMP6 and R1 mice. Marrow cells from SAMP6 mice showed shortened in vitro hematopoiesis; their stromal cells showed greater radiation sensitivity and decreased proliferation. Consistent with those properties, there was constitutive upregulation of transforming growth factor-β(1), an inhibitor of hematopoiesis, and of cell cycle inhibitory genes, p16(INK4A) and p19(ARF). Paradoxically, there was constitutive expression of osteoblast genes in stromal cells from SAMP6 mice, but in vitro matrix mineralization was impaired. These studies and data included in other reports indicate that impaired proliferation of osteoblast progenitors in SAMP6 marrow may be a major factor contributing to accelerated loss of bone mass. In sum, marrow from SAMP6 mice had diminished capacity for long-term hematopoiesis, increased radiosensitivity, and reduced proliferative capacity.     

Overexpression of carcinoma and embryonic cytotrophoblast cell-specific Mig-7 induces invasion and vessel-like structure formation

Molecular requirements for carcinoma cell interactions with the microenvironment are critical for disease progression but are poorly understood. Integrin alpha v beta 5, which senses the extracellular matrix, is important for carcinoma cell dissemination in vivo. alpha v beta 5 signaling induces Mig-7, a novel human gene product that is apparently carcinoma-specific. We hypothesized that Mig-7 expression facilitates tumor cell dissemination by increasing invasion and vasculogenic mimicry. Results show that embryonic cytotrophoblasts up-regulated Mig-7 expression before they acquired an invasive phenotype capable of pseudovasculogenesis. Mig-7 protein primarily co-localized with vasculogenic mimicry markers factor VIII-associated antigen, vascular endothelial-cadherin, and laminin 5 gamma 2 chain domain III fragment in lymph node metastases. Overexpression of Mig-7 increased gamma 2 chain domain III fragments known to contain epidermal growth factor (EGF)-like repeats that can activate EGF receptor. Interestingly, EGF also induced Mig-7 expression. Carcinoma cell adhesion to laminins was significantly reduced by Mig-7 expression. Remarkably, in two-dimensional and three-dimensional Matrigel cultures, Mig-7 expression caused invasion and vessel-like structures. Melanoma cells, which were previously characterized to invade aggressively and to undergo vasculogenic mimicry, expressed Mig-7. Taken together, these data suggest that Mig-7 expression allows cells to sense their environment, to invade, and to form vessel-like structures through a novel relationship with laminin 5 gamma 2 chain domain III fragments.     

Immunohistology of antigen-presenting cells in vivo: a novel method for serial observation of fluorescently labeled cells

PURPOSE: Dendritic cells and macrophages are phagocytic antigen-presenting cells that bridge the innate and acquired immune systems. The coexistence of subtypes of dendritic cells and macrophages with overlapping properties complicates resolution of their precise roles in an immune response within a given tissue. This report documents a method to identify and observe these cells over time in a living animal and thereby to visualize them during a dynamic immune response. METHODS: To label potential antigen-presenting cells, fluorescently tagged ovalbumin was injected into the anterior chambers of mouse eyes. Fluorescently tagged antibodies to cell surface proteins were injected to label specific cell types. Intravital fluorescence microscopy with digital image recording was used to visualize the labeled cells in the irises at various times after the injection. RESULTS: The pattern and density (116-148 cells/mm(2)) of cells labeled in vivo by fluorescent ovalbumin or F4/80 antibodies were similar to that identified by conventional wholemount immunostaining for macrophages and dendritic cells. Fluorescent antibodies specific for CD11b, CD11c, CD80, CD86, or major histocompatibility complex (MHC) class II protein each labeled selective populations of cells in vivo. In contrast to conventional histology, in vivo immunohistology permitted serial observations. The phenotype of cells labeled by fluorescent ovalbumin was not the same at 6 (95% CD11c(+)) and 24 hours (24% CD11c(+)) after injection. CONCLUSIONS: This method of in vivo immunohistology provides a tool for studying cell kinetics and dynamic interactions that cannot be assessed by conventional immunohistology. Furthermore, it avoids potential artifacts from tissue fixation and may work with antibodies that label cells poorly in vitro.     

An analysis of the causes of bladder neck contracture after open and robot‐assisted laparoscopic radical prostatectomy

OBJECTIVES

To evaluate the difference in outcome of bladder neck contracture (BNC) and its causes between large groups of patients undergoing open radical prostatectomy (ORP) and robot‐assisted laparoscopic prostatectomy (RALP).

PATIENTS AND METHODS

We analysed 200 consecutive RPs performed by one surgeon for prostate cancer, 100 by ORP and 100 by RALP, between March 2003 and September 2007. The operative techniques of bladder neck repair and urethro‐vesical anastomosis were different. The ORP patients had a conventional stomatization and ‘racquet handle’ repair of the bladder if necessary, with mucosal eversion and a direct circular interrupted ‘end‐to‐end’ suture anastomosis between the bladder and urethra. The RALP patients had no bladder neck reconstruction or mucosal eversion and their anastomosis was by the continuous suture ‘parachute’ technique.

RESULTS

There was no BNC in the RALP group, whilst 9% of the ORP group developed a BNC (P < 0.005). Apart from surgical technique, other variables, including patient age, previous transurethral resection of the prostate, Gleason score, T stage, urine infection rate, urinary leakage, blood loss, drain tube removal, anastomotic suture material, catheter type and catheter removal times were statistically comparable in both groups.

CONCLUSION

This series suggests that the major factor involved in the cause of bladder neck contracture after ORP, relates to the stomatization or ‘racquet handle’ bladder neck repair, and the end‐to‐end anastomosis between the urethra and stomatized bladder. Mucosal eversion might also contribute. Normal postoperative urinary leakage when the anastomotic apposition is good seems unlikely to be a significant aetiological factor in the development of BNC. Prolonged urinary leakage results from an anastomotic gap, which heals by second intention, thereby causing scarring and BNC. The RALP ‘parachute’ technique, which expands the anastomosis towards the bladder, appears to protect against BNC. Mucosal eversion is not necessary in the parachute repair.     

A Case Study: Percutaneous Lung Biopsy and Symptomatic Arterial Air Embolus

Air emboli are rare complications of computed tomography–guided lung biopsies. This case study discusses current recommendations on patient positioning and supportive treatment until an air embolus is reabsorbed or extracted. A plan of action aimed at mitigating the harmful or even fatal effects of air emboli should be developed and reviewed with all staff participating in these types of procedures.     

Should we educate about the risks of medication overuse headache?

Background

Medication-overuse headache (MOH) is caused by the regular use of medications to treat headache. There has been a lack of research into awareness of MOH. We distributed an electronic survey to undergraduate students and their contacts via social networking sites. Analgesic use, awareness of MOH, perceived change in behaviour following educational intervention about the risks of MOH and preferred terminology for MOH was evaluated.

Findings

485 respondents completed the questionnaire (41% having received healthcare training). 77% were unaware of the possibility of MOH resulting from regular analgesic use for headache. Following education about MOH, 80% stated they would reduce analgesic consumption or seek medical advice. 83% indicated that over the counter analgesia should carry a warning of MOH. The preferred terminology for MOH was painkiller-induced headache.

Conclusions

This study highlights the lack of awareness of MOH. Improved education about MOH and informative packaging of analgesics, highlighting the risks in preferred lay terminology (i.e. painkiller-induced headache), may reduce this iatrogenic morbidity and warrants further evaluation.