Polymyalgia Rheumatica Originally Thought to Be Cervical Spinal Stenosis.

Polymyalgia rheumatica (PMR) is an inflammatory condition that causes joint pain and stiffness. This case report describes an atypical presentation of PMR that was initially misdiagnosed as cervical spinal stenosis, leading to surgery before correctly being diagnosed with PMR. Because of an absence of specific diagnostic tests and a presentation of symptoms that often overlap with other conditions, PMR can be difficult to diagnose. This case highlights the importance of clinical evaluation and awareness of PMR's clinical features to prevent unnecessary interventions and ensure appropriate management.

Differentiation, dedifferentiation, and transdifferentiation of BALB/c 3T3 T mesenchymal stem cells: potential significance in metaplasia and neoplasia.

The expression of defects in the control of cellular differentiation is thought to be of etiological significance in the early stages of carcinogenesis. This possibility is supported by a variety of experimental studies including those that have established that metaplastic changes in cells can represent preneoplastic lesions in vivo. To evaluate this question in greater detail, we have used 3T3 T mesenchymal stem cells as a model system. These cells express certain characteristics of preneoplastic cells even though they can regulate their proliferation and even though they can undergo nonterminal and terminal differentiation into adipocytes. For example, they are immortal and aneuploid, and they show a proclivity to undergo spontaneous or induced neoplastic transformation compared to normal human cells. The question we sought to answer in the current experiments concerns whether predifferentiation growth arrest and/or nonterminal differentiation in such preneoplastic cells is completely reversible or whether these processes induce the expression of the new stable program that limits the cells' proliferative potential and reduces the cells' subsequent differentiation potential in a manner comparable to that which is thought to occur in normal stem cells. The results show that arrest at both the predifferentiation state and at the nonterminal differentiation state is a completely reversible phenomenon that does not limit the cells' subsequent growth or differentiation potential. In fact, the results show that, when nonterminally differentiated 3T3 T adipocytes are induced to dedifferentiate, they can subsequently redifferentiate into macrophages. We therefore suggest that preneoplasia as expressed in 3T3 T mesenchymal stem cells is associated with the expression of defects in the ability to integrally control cellular differentiation and proliferation. As a result, the data suggest that such cells express an increased proclivity to undergo metaplastic change and complete neoplastic transformation.

Cystatin domains in alpha-2-HS-glycoprotein and fetuin.

We have found that chain A of alpha-2-HS-glycoprotein contains two cystatin domains that show closest similarity to those of kininogen. Most likely, the two proteins diverged after the primary duplication of a single cystatin domain as the two cystatin domains of alpha-2-HS-glycoprotein are more similar, especially in disulfide bonding, to the corresponding domains of kininogen than to each other. We also propose that the carboxyl-terminal (non-cystatin) parts of kininogen and alpha-2-HS-glycoprotein contain homologous segments. We suggest that alpha-2-HS-glycoprotein may act as an inhibitor of the cysteine proteinases responsible for bone resorption. We have also found that fetuin is closely related to alpha-2-HS-glycoprotein.

Specific expression of proteins and phosphoproteins in 3T3 T mesenchymal stem cells at distinct growth arrest and differentiation states.

Murine mesenchymal stem cells can be induced to arrest their growth at a series of growth and differentiation states in the G1 phase of the cell cycle. These include the predifferentiation arrest state (GD) at which the integrated control of proliferation and differentiation is mediated, the growth factor/serum deficiency arrest state (GS), and the nutrient deficiency arrest state (GN). Cells at states of reversible nonterminal differentiation (GD') and irreversible terminal differentiation (TD) can also be isolated. In this paper we have employed 1- and 2-dimensional (D) gel electrophoresis to evaluate changes in specific proteins that occur during the various growth and differentiation states of 3T3 T mesenchymal stem cells. The protein composition of membrane, microsome and cytosol preparations of cells arrested at GD, GS and GN states was determined by 2-D gel electrophoresis. More than 50 distinct polypeptides could be identified for each arrest state in gels analysed by a silver staining procedure or by autoradiography following [35S]-methionine labelling. A second series of studies established that a more limited number of differences could be identified if phosphoproteins were analysed by 1-D gel electrophoresis in cells at the GS, GD, GD' and TD states. These results established that one distinct 37 kD phosphoprotein is present in all growth arrested cells and that two distinct differentiation-associated phosphoproteins with molecular weights of 29 kD and 72 kD are present in cells at the GD' and TD states. Thus, the composition of proteins and phosphoproteins in mesenchymal stem cells serves to characterize different states of growth arrest and differentiation.2+he identification of differential