Diffuse subcutaneous emphysema, pneumomediastinum, and pneumothorax after dental extraction

Subcutaneous emphysema, pneumomediastinum, and pneumothorax may result from surgical procedures and trauma and usually do not present a diagnostic dilemma. We present a case of subcutaneous emphysema, pneumomediastinum, pneumothorax, and pneumoretroperitoneum after a dental procedure with an air-and-water-cooled turbine burr drill. This allowed air and water under pressure to be driven into the field and track through the fascial planes. Although this is a common occurrence, these patients frequently go undiagnosed or misdiagnosed as allergic reactions to locally administered anesthetic agents. If a large amount of air is injected, it may track into not only the subcutaneous tissues but also the mediastinum, pleural space, and retroperitoneal space. Patients with significant amounts of air must be admitted, observed for airway compromise, and be provided IV antibiotics and hydration.

Rapid fragmentation of vimentin in human skin fibroblasts exposed to tamoxifen: a possible involvement of caspase-3

Tamoxifen (TAM), an anti-estrogen compound, is widely used for chemotherapy of breast cancer, although the molecular mechanisms underlying TAM cytotoxicity are obscure. Here, we show that TAM dramatically caused degradation of vimentin (VIM) in human skin fibroblasts, in a time and dose dependent manner. Addition of caspase-3 inhibitor, Z-DEVD-FMK, inhibited formation of some fragments of VIM, and caspase-3 was proteolytically activated by TAM treatment. Expression of functional estrogen receptors were negative in these cells, and neither transcription nor protein synthesis was required for TAM-induced degradation of VIM. Moreover, quinestrol, an ethinyl estradiol derivative, weakly degraded VIM, whereas neither estradiols nor estriol had any effects. Taken together, TAM may induce fragmentation of VIM associated with an activation of caspase-3, which may be attributed to non-genomic actions of TAM.

Reversible ischemia increases levels of Alzheimer amyloid protein precursor without increasing levels of mRNA in the rabbit spinal cord

In a rabbit spinal cord ischemia model (RSCIM), the time courses of neuropathological damage of the spinal cord and neurological impairment of the motor functions are well established, demonstrating that the extent of neuropathological damage and the severity of neurological impairment are closely correlated. We used the RSCIM to elucidate the effects of reversible (15 min) and irreversible (60 min) ischemia on the endogenous levels of amyloid protein precursors (APPs) at both the mRNA and protein levels in the caudolumbar/sacral region of the spinal cord. We speculate that endogenous APPs are induced by ischemia as either trophic factors or stress-induced proteins in the RSCIM. A 15-min occlusion transiently increased the APP protein levels in neurons, which returned to the original levels by the end of 60 min occlusion. The increase in APP protein levels during 15-min ischemic insult does not appear to involve regulation at the mRNA level. The increased level of APPs, particularly of the soluble form, could support the possibility that APPs play a neuroprotective role in the RSCIM as stress-induced proteins. In contrast, failure to maintain the increased APP protein levels or to increase the mRNA, as seen in the 60-min ischemia samples, may be one of the causal factors that induce necrosis and neuronal cell death leading to irreversible neurological impairment.

Structural studies of T200 glycoprotein and the IL-2 receptor

Immunological analysis of the cell surface of hematopoietic cells has led to the identification of many different cell membrane molecules, some of which have well-defined functions as receptors. In general, however, the role of most lymphocyte cell surface molecules remains ill-defined even in cases in which antibody inhibition studies have given some insight into the biological processes in which they participate. Here we describe molecular and biochemical studies of T200 glycoprotein (leukocyte-common antigen) and the IL-2 receptor which illustrate the kinds of approaches that can be currently used to characterize individual molecules. T200 glycoprotein is a large Mr glycoprotein found exclusively on leukocytes. However, the exact Mr varies in a cell-type-specific fashion and this property is conserved between different species. Comparison of the rat, mouse and human cDNA sequences show that the large cytoplasmic portion of the molecule is well-conserved, approximately 90%, whereas the exterior portion is only about 50% homologous. Cell-type-specific differences in the primary sequence of the molecule have been identified in the N-terminal portion of the molecules. In contrast to T200, the function of the IL-2 receptor is well-known. The interaction of IL-2 with its receptor provides a growth signal that determines the magnitude and duration of T-cell responses. Limited proteolysis studies provide the first direct biochemical evidence that the external region of the IL-2 receptor consists of two independent domains. 125I-labeled IL-2 has been chemically crosslinked to the receptor and proteolytic cleavage of the crosslinked product indicates that IL-2 is selectively bound to the N-terminal domain of the receptor.