VS38: a new monoclonal antibody for detecting plasma cell differentiation in routine sections.

AIMS--To characterise a new mouse monoclonal antibody, VS38, which recognises an intracytoplasmic antigen of 64 kilodaltons present in normal and neoplastic plasma cells; and to establish its value as a diagnostic reagent for routine pathological practice. METHODS--A range of normal and neoplastic tissue sections, both frozen and routinely fixed, were immunostained, using the microwave method of antigen retrieval for routinely fixed specimens. The antibody was also tested on blood and bone marrow specimens and a range of human cell lines. The molecular weight of the antigen recognised by the antibody was obtained by western blot analysis. FACS analysis was used to demonstrate the cellular location of the antigen and its presence on tonsil cell suspensions and myeloma cases. RESULTS--VS38 recognised normal and neoplastic plasma cells in all of the tissues, including all routinely fixed plasma cell neoplasms tested. The antibody also weakly stained epithelial elements within the tissue but was absent from haemopoietic cells of other lineages. CONCLUSION--Antibody VS38 is of potential value in identifying myeloma or plasmacytoma in bone marrow or other tissues. It differentiates lymphoplasmacytoid lymphoma from lymphocytic and follicular lymphoma. It also subdivides large cell lymphomas into two groups which may be a more reliable method of separating these tumours than morphology alone.     

Fate of the monoamine oxidase inhibitor pargyline in cultured hepatocytes

The interaction of the monoamine oxidase inhibitor pargyline with cultured hepatocytes has been studied. [Phenyl-3, benzyl-3H] pargyline (38 nM) rapidly enters the cells and a plateau of incorporation into a trichloroacetic acid insoluble form (monoamine oxidase) is reached after 2 hr. The level of labelling is lower in freshly isolated cells than in those in later culture. The maximum incorporation accounts for only 6% of the added radioactivity and produces a 9% inhibition of monoamine oxidase activity. The remaining [3H] pargyline is metabolized and quickly accumulates in the cell culture medium in a form which cannot label exogenous mitochondria. The metabolism of pargyline varies both qualitatively and quantitatively with culture age. In 0 hr and 20 hr-cultured cells one metabolite preferentially appears whilst in 140 hr cultured hepatocytes at least three metabolites are formed. The metabolism of [3H] pargyline in early culture is consistent with a cytochrome P-450 involvement. The use of [3H] pargyline to label monoamine oxidase in cultured hepatocytes offers several attractive features for studying the turnover of this enzyme. These include speed of interaction, non-reutilization, application to normal cells, controlled inhibition of monoamine oxidase and metabolism of non-specific label.     

Regulation of osteoblast differentiation by Pasteurella multocida toxin (PMT): a role for Rho GTPase in bone formation.

The role of the Rho-Rho kinase signaling pathway on osteoblast differentiation was investigated using primary mouse calvarial cells. The bacterial toxin PMT inhibited, whereas Rho-ROK inhibitors stimulated, osteoblast differentiation and bone nodule formation. These effects correlated with altered BMP-2 and -4 expression. These data show the importance of Rho-ROK signaling in osteoblast differentiation and bone formation. INTRODUCTION: The signal transduction pathways controlling osteoblast differentiation are not well understood. In this study, we used Pasteurella multocida toxin (PMT), a unique bacterial toxin that activates the small GTPase Rho, and specific Rho inhibitors to investigate the role of Rho in osteoblast differentiation and bone formation in vitro. MATERIALS AND METHODS: Primary mouse calvarial osteoblast cultures were used to investigate the effects of recombinant PMT and Rho-Rho kinase (ROK) inhibitors on osteoblast differentiation and bone nodule formation. Osteoblast gene expression was analyzed using Northern blot and RT-PCR, and actin rearrangements were visualized after phalloidin staining and confocal microscopy. RESULTS: PMT stimulated the proliferation of primary mouse calvarial cells and markedly inhibited the differentiation of osteoblast precursors to bone nodules with a concomitant inhibition of osteoblastic marker gene expression. There was no apparent causal relationship between the stimulation of proliferation and inhibition of differentiation. PMT caused cytoskeletal rearrangements because of activation of Rho, and the inhibition of bone nodules was completely reversed by the Rho inhibitor C3 transferase and partly reversed by inhibitors of the Rho effector, ROK. Interestingly, Rho and ROK inhibitors alone potently stimulated osteoblast differentiation, gene expression, and bone nodule formation. Finally, PMT inhibited, whereas ROK inhibitors stimulated, bone morphogenetic protein (BMP)-2 and -4 mRNA expression, providing a possible mechanism for their effects on bone nodule formation. CONCLUSIONS: These results show that PMT inhibits osteoblast differentiation through a mechanism involving the Rho-ROK pathway and that this pathway is an important negative regulator of osteoblast differentiation. Conversely, ROK inhibitors stimulate osteoblast differentiation and may be potentially useful as anabolic agents for bone.     

The emerging role of induced hypothermia in the management of acute stroke.

Current treatment of acute stroke remains unsatisfactory. This review presents experimental and clinical data which suggest that mild induced hypothermia could be a potent and practicable neuroprotective treatment of acute ischaemic stroke and intracerebral haemorrhage. Hypothermia, if proven to be safe, effective and widely practicable in patients with acute stroke, could have an enormous positive impact on reducing the burden of stroke worldwide. Critical issues that will need to be considered in a well designed randomised controlled trial of induced hypothermia in acute stroke patients are discussed.     

Predictors of incident depression after hip fracture surgery.

OBJECTIVE: Depression after hip fracture surgery is prevalent and associated with increased mortality rates and impaired functional recovery. The incidence of new-onset depressive symptoms in patients initially not depressed after hip fracture surgery and their relationship with functional recovery is unknown. METHODS: A cohort of 139 nondepressed elderly patients (>60 years) hospitalized for hip fracture surgery were followed up for six months. Clinically significant depressive symptoms were defined as a score of 7 or more on the 15-item Geriatric Depression Scale. RESULTS: The authors found a cumulative incidence rate of 20.5% adjusted for dropouts. Multiple Cox-regression analyses yielded the presence of subthreshold symptoms of depression, anxiety, pain, and cognitive impairment at baseline, the premorbid level of mobility, and a history of (treated) depression as risk factors for incident depression (p <0.05). A forward, conditional procedure identified postoperative pain (hazard ratio [HR] = 1.32, 95% confidence interval [CI]: 1.14-1.53, Wald chi(2) = 13.57, df = 1, p <0.001) and baseline anxiety (HR = 1.25, 95% CI: 1.08-1.44, Wald chi(2) = 8.86, df = 1, p = 0.003) as the strongest independent risk factors. Incident depression was associated with a less favorable outcome at 3 months follow-up. CONCLUSION: This exploratory study identified two treatable baseline characteristics that predicted incident depression in nondepressed patients after hip-fracture surgery.     

Recommendations for the reporting of tissues removed as part of the surgical treatment of cutaneous melanoma: Association of Directors of Anatomic and Surgical Pathology

The Association of Directors of Anatomic and Surgical Pathology have developed recommendations for the surgical pathology report for common malignant tumors. The recommendations for cutaneous melanoma are reported herein.     

Evidence for P2-purinoceptors on human osteoblast-like cells.

ATP released from damaged cells or by controlled secretion could be an important factor in the formation or remodeling of bone. In a variety of other tissues ATP has been shown to control cellular processes by acting on P2-purinoceptors and activating the calcium signaling pathway. Here we demonstrate for the first time that extracellular ATP increases the intracellular free calcium [Ca2+]i concentration in normal human osteoblasts and in SaOS-2 cells, a human osteosarcoma-derived cell line, but not in ROS 17/2.8 cells. The ATP-induced increase in [Ca2+]i was dose dependent, and the concentrations of ATP required were similar to those reported to regulate cellular functions in other cell types. Although ATP is metabolized rapidly by bone cells, the effects on [Ca2+]i appeared to be mediated directly by ATP rather than one of its metabolites. Adenosine 3-thiotriphosphate, a nonhydrolyzable analog of ATP, induced similar changes in [Ca2+]i. This indicates that P2-purinoceptors are present on osteoblast-like cells and that extracellular ATP from various sources might be an important factor in the regulation of osteoblast functions.