Complement mediated inhibition of immune precipitation in rheumatoid arthritis: studies on interaction of heat aggregated IgG with IgM rheumatoid factor.

Serum samples from patients with seropositive rheumatoid arthritis contain an inhibitor of complement mediated inhibition of immune precipitation (CMIP). This inhibitory effect can be produced by the addition of either purified monoclonal or polyclonal IgM rheumatoid factor (RF) to human serum. The specificity of the rheumatoid factor influences the degree of inhibition, and when precipitation occurs the rheumatoid factor coprecipitates with the antigen-antibody complex. In rheumatoid sera there was a significant positive correlation between IgM RF concentration and inhibitory activity, though the range of inhibitory activity seen for the same concentration of rheumatoid factor was considerable. Small quantities of heat aggregated IgG (HAGG) had a much greater effect on the measurement in an enzyme linked immunosorbent assay (ELISA) of IgM RF than they did on the inhibitory activity of IgM RF in the CMIP assay. Larger quantities of HAGG initiated complement activation and increased the precipitation of immune complexes. IgM RF reduced the complement activating properties of HAGG by reducing the amount of Clq which bound to the aggregate. The mechanisms by which IgM RF overcomes CMIP in rheumatoid sera may involve its inhibitory effects on the binding of Cl to the antigen-antibody complex.     

Micrometastases: marker of metastatic potential or evidence of residual disease?

BACKGROUND: Micrometastases within bone marrow have been shown to indicate a poor prognosis in patients with epithelial tumours. However, the degree to which micrometastases represent true residual disease or cell shedding and metastatic potential, is unclear. AIM: To explore whether micrometastases represent residual disease, bone marrow taken from carefully staged patients before and after (> 6 months) "curative" resection of a primary gastrointestinal cancer was studied prospectively. PATIENTS/METHODS: Seventy two consecutive patients were studied; the only exclusions were patients with known overt metastatic disease at the time of surgery. Micrometastatic cells were quantified per 10(5) marrow cells by flow cytometry after staining for contaminant cytokeratin-18 positive cells. RESULTS: Micrometastases were detected preoperatively in 22% (16/72) of all patients, comprising 11 (23%) of 48 with colorectal cancer, five (33%) of 15 with gastric adenocarcinoma and none (0%) of nine with oesophageal squamous cancer. Although fewer metastatic cells were detected in postoperative bone marrow, and clearance of marrow deposits was evident in most patients, the persistence of micrometastases in five of 16 patients after resection, without evidence of tumour recurrence, indicates a subset with true residual disease. Detection of micrometastases postoperatively (persistent or newly developed) was significantly associated with development of overt metastases during the subsequent 12-18 months of follow up (nine of 19 patients) when compared with patients testing negative for micrometastases (eight of 53; p < 0.01). CONCLUSIONS: Preoperative detection of micrometastases may reflect either transient shedding of cells, metastatic potential or residual disease, but postoperative micrometastases indicate minimal residual disease. Identification of these patients is important because they may benefit from adjuvant therapy.     

Radiographic texture analysis of densitometric calcaneal images: Relationship to clinical characteristics and to bone fragility

Osteoporotic fractures are related not only to bone mineral density (BMD) but also to bone structure or microarchitecture, which is not assessed routinely with currently available methods. We have developed radiographic texture analysis (RTA) for calcaneal images from a peripheral densitometer as an easy, noninvasive method for assessing bone structure. We conducted a cross‐sectional study of the relationship between RTA and prevalent vertebral fractures (n = 148) among 900 subjects (ages 19 to 99 years, 94 males) referred for bone densitometry as part of their routine medical care. RTA features were derived from Fourier‐based image analysis of the radiographic texture pattern (including root mean square, first moment, and power spectral analyses). RTA features were associated with age, weight, gender, and race, as well as glucocorticoid use. When controlling for clinical risk factors and BMD (or a summary measure calculated using FRAX algorithms), RTA features were significantly different for subjects with and without prevalent vertebral fractures [adjusted odds ratio (OR) = 1.5 per 1 standard deviation (SD) decrease in RTA feature beta, 95% confidence interval (CI) 1.2–1.8, p = .001]. Gender and use of pharmacologic therapy for osteoporosis did not significantly affect this association, suggesting that RTA can be applied to a wide range of densitometry patients. We conclude that RTA obtained using a portable instrument has a potential as a noninvasive method to enhance identification of patients at increased risk of osteoporotic fractures. Copyright © 2010 American Society for Bone and Mineral Research     

Nurse practitioners and physician assistants revisited: do their practice patterns differ in ambulatory care?

The education and regulation of nurse practitioners and physician assistants would suggest unique role differentiations and practice functions between the professions. This study explored to what extent their practice patterns in primary care actually differ. It was hypothesized that the primary care services provided by nurse practitioners would tend to be women and family health services, health prevention and promotion oriented, provided to minority and socioeconomic disadvantaged patients, and less dependent on physician supervision. In contrast, the services provided by physician assistants would more likely be medical/surgical oriented; diagnostic, procedural, and technical in nature; likely to be in rural areas; and more dependent on physician supervision. The study used patient data from the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey. Although some differences emerged, the argument is not compelling to suggest strong, unique, practice differences across all ambulatory care settings between the two types of nonphysician providers. It is the specific type of ambulatory setting that influences the practice pattern for both provider groups. If practice patterns are less distinctive than previously believed, more opportunities for interdisciplinary education need to be explored, and health policies that promote a discipline-specific primary care workforce may need to be reexamined.     

Comparison of forehead and digit oximetry in surgical/trauma patients at risk for decreased peripheral perfusion

OBJECTIVE: Measurement of pulse oximetry (Spo(2)) is often impaired in critically ill patients. Forehead reflectance oximetry, the Max-Fast (Nellcor, Pleasanton, CA), may be less susceptible to poor tissue perfusion and could improve accuracy of oxygen saturation measurement. The objective of this study was to evaluate the use of forehead oximetry measures in critically ill surgical/trauma patients. METHODS: A prospective interventional study of 30 critically ill surgical/trauma patients at risk for decreased peripheral perfusion, as evidenced by need for vasopressor support (24 patients), transfusion of more than 6 unit packed cells in 24 hours (two patients), or an inability to obtain consistent saturation from a digit sensor (four patients), compared forehead and digit-based oximeter Spo(2) readings with co-oximetry (Sao(2)) measurements from arterial blood samples. Sao(2) values were converted to functional oxygen saturation (SO(2)) measurements for the final comparison. Patients were fitted with forehead (Nellcor Max-Fast) and digit (Nellcor Max A; digit 1) sensors connected to Nellcor OxiMax N-595 oximeters and a digit sensor (Nellcor Max A; digit 2) connected to a multiparameter monitor (Philips CMS [Andover, MA]). Three measurements of Sao(2) were obtained from each subject over a 24-hour time period, and simultaneous measurements of Spo(2) were recorded from the three monitors. RESULTS: The three Spo(2) measurements (forehead, digit 1, and digit 2) were compared with SO(2) values using the Bland-Altman method to assess agreement. Forehead measurements demonstrated a mean bias of -1.39, whereas digit 1 was -2.61 and digit 2 was -3.84. Pearson correlations (r) for forehead, digit 1, and digit 2 with SO(2) were .834, .433, and .254, respectively. There were fewer unsuccessful measurements with the forehead oximetry technique. CONCLUSIONS: Forehead sensors improve measurement of oxygen saturation in critically ill surgical/trauma patients at risk for decreased peripheral perfusion.     

Clinical experience reported by candidates for the American Board of Obstetrics and Gynecology 1995 and 1997 oral examinations

OBJECTIVE: The purpose of this study was to report the clinical experience collated from the 1995 and 1997 case list summary sheets of United States and Canadian active candidates who were completing the American Board of Obstetrics and Gynecology oral examination for the first time. STUDY DESIGN: Data from the case list summary sheets were entered into a computerized database and collated. Data from active candidates who had subspecialty training and from other international graduates were excluded. RESULTS: The difference in the ratio of men to women candidates between 1995 and 1997 was statistically significant (P =.02). Both years, 31% of the major operations were hysterectomies, of which 60% and 62.5%, respectively, were performed through an abdominal incision. The mean total cesarean delivery rate was 20.5% in 1995 and 19.7% in 1997. The ratio of primary to repeat cesarean deliveries was 2 to 1 in both years. The ratio of forceps to vacuum extraction deliveries was 3:7 in 1995 and 2:5 in 1997. CONCLUSION: This data set provides a national overview of the clinical experiences of a relatively homogeneous group of practicing obstetrician-gynecologists who have recently completed their training.