Assessing wound severity with color and infrared imaging of reactive hyperemia

This study examined the use of cutaneous reactive hyperemia as a means for noninvasive assessment of wound severity of newly formed temperature-modulated pressure injuries in a porcine model. Two methods to quantify the extent of the reactive hyperemic reflex were developed. First, color image analysis was used to measure the hue of injured tissue. The specific hue of the skin surface of the wounded site was found to provide an indication of the severity of the wounds. Second, infrared imaging, coupled with computer image processing, was used to detect differences in skin temperature. The relative surface temperature of the wounds showed a strong correlation with the presence or absence of deep tissue injury. Both techniques correlated with the severity of the injuries as determined by a histologic assessment of biopsied tissue, but infrared imaging provided the better means to assess wound depth.     

The microscopic distribution of 99mTc-labelled phagocytes in resected bowel in patients with acute Crohn's disease: correlation with histological changes

Abdominal scintiscans performed after the injection of autologous phagocytes labelled with ^99mTc-stannous colloid particles provide an accurate assessment of the extent of disease in active inflammatory bowel disease. To study the correlation between phagocyte accumulation and histological indices of the degree of inflammation within bowel wall, the distribution of radiolabel within five freshly resected specimens of ileum and one of colon was assessed in five patients with active Crohn's disease. Each patient was injected with autologous ^99mTc-labelled phagocytes prior to surgery. Multiple tissue samples (blocks) were taken along the length of the fresh resected specimen of bowel. The radioactive count of each block was obtained and they were then studied independently by two histopathologists who graded 12 histological features according to predefined criteria. High counts correlated with ulceration and submucosal mononuclear aggregates (P < 0.05). Very low counts were obtained in mesentery and non-ulcerated bowel. This study confirms the selective accumulation of ^99mTc-labelled phagocytes within areas of ulcerated bowel in patients with active Crohn's disease.     

Inhibition of calcineurin phosphatase activity in adult bone marrow transplant patients treated with cyclosporine A

In vitro studies have demonstrated that cyclosporine A (CsA) acts by inhibiting the phosphatase activity of calcineurin, an important mediator of T-cell activation. The relationship of CsA administration in vivo, calcineurin activity, and graft-versus-host disease (GVHD) has yet to be studied. The calcineurin activities of mononuclear cells isolated from 62 bone marrow transplant recipients and 12 normal volunteers were determined and analyzed with respect to administration of CsA, presence or absence of CsA in plasma, and presence or absence of GVHD. Of 62 patients, 33 were taking CsA and 29 were not. Early posttransplant (< 100 days), the calcineurin activity of patients on CsA was significantly lower than that of patients not on CsA (P = .0004) and than that of normal volunteers (P < .0001). Similarly, late posttransplant (> 100 days), the calcineurin activity of patients taking CsA was inhibited compared with normal volunteers (P < .05). The calcineurin activity of patients with acute GVHD who were taking CsA was lower than that of patients on CsA without acute GVHD matched for time posttransplant (P = .02). Calcineurin activity in patients on CsA with chronic GVHD was similar to those without chronic GVHD on drug. In conclusion, calcineurin activity is significantly suppressed by in vivo administration of CsA. The lower calcineurin activity of patients on CsA with acute GVHD suggests that CsA-resistant GVHD is not the result of inadequate suppression of calcineurin activity. These data suggest that if inhibition of calcineurin is the only physiologic target of CsA administration, simply increasing doses of CsA or treatment with other inhibitors of calcineurin, such as FK506, would not be expected to ameliorate GVHD.     

Use of monoclonal antibodies to identify cerebrospinal fluid lymphoblasts in children with acute lymphoblastic leukemia

The identification of small numbers of leukemic cells in the cerebrospinal fluid (CSF) presents a diagnostic problem in the treatment of children with acute lymphoblastic leukemia (ALL). We adapted a latex sphere rosetting technique to allow us to identify simultaneously cell surface markers and cell morphology in 199 CSF samples from 34 patients and 14 control subjects. In patients without leukemic meningitis, the majority of CSF lymphocytes (69%) were found to be mature T cells positive for OKT11. A much smaller number of cells (8%) were found to be B cells positive for la. In these children, only 3% of CSF lymphoid cells expressed the common acute lymphoblastic leukemia antigen (CALLA). Similar results were found in the control subjects. By contrast, 28 CSF samples from nine children with varying numbers of CSF lymphoblasts had much greater proportions of CALLA- and la-positive CSF cells (24% to 96%). Leukemic meningitis was present in one of these patients and later developed in four others. However, three patients with small numbers of lymphoblasts present but with low proportions of CALLA-positive CSF cells (less than 5%) subsequently had normal CSF examinations. We found the use of this rosetting technique valuable in providing information complementary to that obtained from cell morphology alone about the possible malignant nature of small numbers of lymphoblast-like CSF cells seen on cytocentrifuge preparations in children with ALL.     

Optical imaging and electrophysiology of rat barrel cortex. I. Responses to small single-vibrissa deflections

A study was undertaken to investigate the response of the rodent somatosensory barrel cortex to single-whisker, near-threshold vibrissal stimuli. Cortical responses to controlled whisker deflections were recorded by (i) conventional multi-unit extracellular recording within the cytochrome oxidase rich barrels centers and the interbarrel septa, and (ii) intrinsic signal optical imaging, a technique that provides a spatial view of cortical activation thought to be related to the deoxygenation of hemoglobin in activated areas. Barrel cortex neurons responded weakly to whisker deflections of 0.04 degrees. Their response to a series of small stimuli of increasing amplitude was well-fitted by a logarithmic function. Responses to larger stimuli declined monotonically with distance from the center of the barrel column, and were characterized by greater onset and offset firing rates, by greater post-excitatory reduction of firing to below spontaneous levels, and by shorter response latency. In comparison to measurements taken previously from primary vibrissal afferent fibers, we conclude that cortical cells can respond to activity in a very small fraction of first-order sensory neurons.