Computed radiography in musculoskeletal imaging: state of the art.

Computed radiography is a 2K x 2K x 10 bit digital radiographic system that replaces the film-screen combination with a photo-stimulable phosphor plate. The advantages of this relatively new technology include linear detector response, improved detector efficiency, and digital processing capabilities. Musculoskeletal applications benefit significantly from these attributes, which result clinically in the ability to reduce both radiation dose and number of exposures. Studies of observers' performance have shown no statistically significant difference in diagnostic accuracy between film-screen and computed radiographic musculoskeletal images. Computed radiography is particularly useful in the evaluation of the musculoskeletal system in traumatized patients with portable radiographs, spine radiographs, scoliosis studies, and depiction of soft-tissue abnormalities. Limitations include change in image format and size, high cost, decreased spatial resolution, restricted throughput, increased perception of noise, and new artifacts that must be recognized. Spatial resolution limitations of computed radiography in identification of fine detail information can be improved by using magnification techniques. Radiation dose reduction with an exposure decrease of 25-50% can be achieved without loss of diagnostic accuracy, although this depends on the examination and the abnormality. An interactive workstation is important in the use of a computed radiographic system with capabilities to adjust display parameters to best depict images and disease. We conclude that computed radiography is an alternative to film-screen radiography without significant differences in diagnostic quality in the evaluation of musculoskeletal images.     

Multiply Recurrent Trichilemmal Carcinoma With Perineural Invasion and Cytokeratin 17 Positivity

BACKGROUND: Trichilemmal carcinoma is an uncommon cutaneous malignancy that is thought to be the malignant counterpart of the trichilemmoma. Despite histologic features such as pronounced cytologic atypia, trichilemmal carcinoma is often described as having a rather benign clinical course. Cases of tumor recurrence after therapy are uncommon, and tumor neurotropism has never been described. OBJECTIVE: A case of multiply recurrent trichilemmal carcinoma with perineural invasion is described. The outer root sheath differentiation of this neoplasm is confirmed with the use of novel antibodies directed toward cytokeratins that are expressed in this area of the hair follicle. METHODS: The trichilemmal carcinoma was excised using the Mohs surgical technique. Tissue obtained during the extirpation of the tumor was subjected to immunohistochemical staining for cytokeratin 15, cytokeratin 17, and c-erb-B2. RESULTS: Tumor neurotropism was noted. The trichilemmal carcinoma demonstrated abundant cytoplasmic staining for cytokeratin 17 and c-erb-B2. CONCLUSIONS: In distinction to previous reports, this case reveals that trichilemmal carcinoma can demonstrate significant biological aggression, as reflected by tumor neurotropism and by failure to respond to multiple surgical excisions. The purported outer root sheath differentiation of this neoplasm is confirmed with the use of novel immunohistochemical staining. This immunohistochemical staining may be useful in differentiating trichilemmal carcinoma from other clear cell neoplasms.     

Another case of use of the ProSealTM laryngeal mask airway in a difficult obstetric airway

Editor—We read with interest the case report by Awan andcolleagues,¹ describing successful use of the ProSeal^TM laryngealmask airway (PLMA) after failed tracheal intubation in a parturientundergoing Caesarean section. After securing the airway withthe PLMA, the authors removed it and tried again to performtracheal intubation. We think that the PLMA can be left in placeand used as a definitive airway after failed intubation in Caesareansection. We report another case where the PLMA     

Increased monocyte Fc-dependent chemiluminescence in renal transplant patients

A luminol-enhanced chemiluminescence (CL) assay was used to study the microbicidal potential of phagocytic cells and the opsonic properties of serum in renal transplant recipients. Thirty-four patients receiving maintenance immunosuppression with prednisone and either cyclosporine or azathioprine and 35 normal controls were studied. Polymorphonuclear leukocytes (PMN) and monocytes were stimulated at the Fc receptor with heat-aggregated IgG (HAIgG) or immunoglobulin-treated zymosan (ITZ), and at the C3b receptor with serum-treated zymosan. Serum opsonic activity was determined by incubating zymosan with normal or patient serum and stimulating the CL response of normal phagocytes. We found that the Fc and C3b-dependent CL of PMN, the C3b-dependent CL of monocytes, and the opsonic properties of serum were identical in transplant recipients and normal controls. In contrast, the Fc-dependent CL of monocytes in renal transplant patients was 3 times greater than normal when stimulated with either soluble (HAIgG) or particulate (ITZ) ligands. These data suggest that some components of the host immune system are not affected by maintenance immunosuppressive medication in renal transplant recipients. The mechanisms and significance of the increased Fc-receptor-dependent CL observed in monocytes of renal transplant patients remain to be determined.     

Effect of steel wire sutures on the incidence of chemically induced rodent colonic tumours

An experiment is presented which shows that colonic primary tumours cluster around a previously constructed anastomosis and that the choice of suture materials (but not the technique of their insertion) can influence this. In a rodent model where dimethylhydrazine was administered 2 months after surgery, anastomotic tumours were most often seen when wire sutures--as used in the staples of anastomotic stapling guns--had been employed (10 out of 16 large bowel tumours were anastomotic as compared with 2 of 12 in a silk sutured group, P = 0.019). An explanation may be that wire sutures persist much longer than silk (in the experiment, 10 months after insertion, 4 per cent of silk sutures were still present, 15 per cent of wire, P less than 0.01). This was translated into a greater degree of scarring at the anastomosis, being most severe in the presence of persisting sutures. Of the 12 anastomotic tumours found in both groups, 7 (58 per cent) were in the minority (17-26 per cent) who had persisting sutures and the remaining 5 in the 47 who had none. Techniques of suturing (needle always passed from the serosa in; needle from mucosa out--the latter in such a way that mucosal cells could be displaced into the bowel wall where it was supposed that they might be more susceptible to subsequent carcinogenesis) did not affect tumour yield. We suggest that non-absorbable sutures, and especially stainless steel wire, should not be used when constructing an anastomosis after large bowel cancer surgery.     

Neointimal hyperplasia in balloon-injured rat carotid arteries: the influence of hyperhomocysteinemia.

PURPOSE: Hyperhomocyst(e)inemia (hH[e]) is a risk factor for atherosclerosis. Neointimal hyperplasia (NH) after vessel injury can contribute to atherosclerosis. In this study, we investigated the effects of hH(e) on NH formation after arterial balloon injury in rats. METHODS: Lewis rats that were given a hH(e)-inducing (high methionine, low folate) or normal diet for 150 days underwent common carotid artery (CCA) balloon injury. Two and 4 weeks after injury, CCAs were formalin perfusion-fixed, sectioned, and stained for elastin. Neointimal index (NI, percent lumen occlusion) and neointima (N) and media (M) area were measured by using computer-interfaced microscopy. RESULTS: Plasma homocyst(e)ine (H[e]) levels were elevated in rats given the study diet compared with rats given the normal diet at days 40 and 90 (69 +/- 8 and 73 +/- 9 micromol/L vs 4 +/- 0.4 and 4 +/- 0.6 micromol/L, P <.001). After balloon injury, the CCA NI and N/M ratio, but not the M area, were increased by hH(e) compared with normal plasma H(e) (2 weeks [n = 6,7]: NI = 7.3 +/- 1.7 vs 2.9 +/- 0.7, P =.002, and N/M = 0.31 +/- 0.08 vs 0.08 +/- 0.02, P <.001; 4 weeks [n = 4,7]: NI = 13.1 +/- 2.2 vs 6.3 +/- 1.3, P =.002, and N/M = 0.36 +/- 0.08 vs 0.17 +/- 0.03, P <.001). CONCLUSION: hH(e) accelerates NH in a rat CCA balloon-injury model. The effect of hH(e) on NH may contribute to increased atherosclerosis in humans with hH(e).     

Acute vascular rejection is associated with up-regulation of vitronectin receptor (alphavbeta3), increased expression of tissue factor, and activation of the extracellular matrix metalloproteinase induction system.

BACKGROUND: A cascade of inflammatory reactions characterize acute vascular rejection after heart transplantation. This study was undertaken to test the hypothesis that acute vascular rejection is associated with up-regulation of vitronectin receptor (alphavbeta3), increased expression of tissue factor, and activation of the extracellular matrix metalloproteinase induction system. METHODS: Acute vascular rejection developed in 14 heart transplant recipients within 2 weeks of transplantation, confirmed by immunofluorescence (AVR group). We compared these patients with 10 transplant recipients who had no evidence of acute vascular rejection or peritransplant ischemic injury (control group). We evaluated endomyocardial biopsy specimens for alphavbeta3, tissue factor, and extracellular matrix metalloproteinase inducer (EMMPRIN). RESULTS: Compared with the control group, the AVR group demonstrated evidence of significantly increased expression of alphavbeta3 (1.9-fold, p < 0.001), tissue factor (1.8-fold, p < 0.001), and EMMPRIN (1.5-fold, p < 0.001). All patients in the AVR group received plasmapheresis; 11 of 14 patients had evidence of ischemic necrosis on biopsy specimens, and 3 of 14 patients experienced hemodynamic compromise and graft dysfunction and died within 3 weeks of transplant. Another patient died at 10 months after transplant. CONCLUSIONS: Acute vascular rejection is associated with up-regulation of alphavbeta3, tissue factor, and activation of the matrix metalloproteinase induction system, which may contribute to the lethal morbidity associated with this disease.     

Interaction between Marihuana and Ethanol: Effects on Psychomotor Performance

This is a report of the results of a placebo-controlled study in which the effects of the interaction between ethanol and marihuana on drug plasma concentrations, subjective ratings of intoxication, heart rate acceleration, and psychomotor performance were investigated. Six healthy, male, paid volunteers, moderate users of ethanol and marihuana, participated in the study. Ethanol (0.42 g/kg, 0.85 g/kg, or placebo) was administered over a 30-min interval. Fifteen minutes later the subjects smoked, in their customary manner, NIDA cigarettes containing 2.4% or 0.0004% (placebo) delta-9-tetrahydrocannabinol (THC). Each subject was tested in a single-blind, latin-square crossover design with the following six conditions: placebo ethanol/placebo marihuana; low dose ethanol/placebo marihuana; high dose ethanol/placebo marihuana; placebo ethanol/marihuana; low dose ethanol/marihuana; and high dose ethanol/marihuana. The variables measured in the study were: (a) subjective rating of ethanol and/or marihuana intoxication; (b) heart rate; (c) accuracy and latency of response in the Simulator Evaluation of Drug Impairment (SEDI) task; (d) blood ethanol concentration by gas chromatography; and (e) plasma concentration of THC by radioimmunoassay. The results indicate that the decrements due to ethanol in performance of skills necessary to drive an automobile were significantly enhanced by marihuana in an additive and perhaps synergistic manner. The administration of ethanol prior to marihuana smoking did not produce significant effects on the subjective rating of "high," heart rate acceleration, or THC plasma concentration.