Heterobifunctional poly(ethylene oxide) oligomers containing carboxylic acids.

Syntheses of vinylsilyl alcohols having one to three vinyl moieties and their use as initiators for ethylene oxide polymerizations are discussed. Poly(ethylene oxide) oligomers with vinylsilanes at one end and a hydroxyl group at the other were prepared in base-catalyzed reactions. Molecular weights determined from 1H NMR and gel permeation chromatography were close to the targeted values. Carboxylic acid functional poly(ethylene oxide) oligomers were prepared from ene-thiol addition reactions of mercaptoacetic acid across the vinylsilane terminus. It is anticipated that these carboxylic acid functional oligomers will complex to magnetite nanoparticles to afford complexes that can be dispersed in aqueous media.

Development and duration of radiographic signs of bone healing in children.

OBJECTIVE: Few articles report the evaluation of pediatric fracture healing and dating based on radiographic appearance. We established a timetable for expected radiographic changes visible during bone healing in otherwise healthy children. MATERIALS AND METHODS: We examined 707 radiographs of fractured forearms in 141 patients. Each fracture was assessed by a pediatric radiologist who was unaware of the timing of the initial injury. Assessment included the following features: fracture margins, fracture gap, periosteal reaction, callus, bridging, and remodeling. The time interval between injury and the appearance of the radiographic features and the duration of radiographic signs were determined and correlated with age, sex, angulation, displacement, and location. RESULTS: Sclerosis at the fracture margins was evident in 85% of fractures 5 weeks after injury. Widening of the fracture gap was observed in 62% of fractures at 6 weeks. Periosteal reaction was evident on all images by 4 weeks, and after 7 weeks, periosteal reaction was separable from cortex in only 10% of fractures. Fracture callus had a density equal to or greater than that of adjacent cortex 10 weeks after injury in 90% of fractures. CONCLUSION: A wide variation exists in the appearance and duration of the radiographic signs of bone healing. Marginal sclerosis should be an expected radiographic sign of normal bone healing. Applying maximum and minimum time spans to objective radiographic signs may aid in fracture dating.

Measuring case mix and severity of illness in Canada: case mix groups versus refined diagnosis related groups.

This study compares the effectiveness of Case Mix Groups (CMG*) groups and Refined Diagnosis Related Groups (RDRG) in reducing Canadian length of stay (LOS) variability. The effectiveness of the two case mix grouping methodologies was assessed with a common data base, 282,459 abstracts with ICD-9 CM diagnosis codes reported to the Hospital Medical Records Institute (HMRI) from January to March 1989. Death, signouts, transfers to or from acute care institutions and cases with an outlier LOS ("atypical" cases) were excluded from the analysis. HMRI utilization management reports to acute care hospitals use a data base defined in this way. On the basis of the variance reduction statistic (R2) from ordinary least squares regression analysis, CMG groups were found to be slightly more effective than RDRGs in reducing LOS variability. R2 statistics were 45.7 and 43.8 for CMG groups and RDRGs, respectively. Within subgroups of cases, CMG groups were found to be markedly more effective with the newborn/neonate group and to a lesser extent with non-surgical cases. The severity of illness categories within RDRGs did not, over all "typical" cases in the data base, yield more homogeneous groups of cases than CMG groups, which have half the number of categories. The value of tailoring severity measurement to Canadian medical practice and Canadian diagnosis coding is highlighted.

Infra-isthmal fractures of the femur: a review of 82 cases.

Eighty-two infra-isthmal fractures of the femur were reviewed in order to develop a fracture classification, to determine the results of treatment, and to define the best treatment methods for certain specific fracture patterns. Type I (transverse or short oblique) fractures were seen in 36 patients (mean age, 33 years). They had a 25% complication rate when treated by open reduction, and a high malunion rate when treated by closed means. Type II (spiral or long oblique) fractures were generally caused by falls, and were seen in 36 patients (mean age, 56 years). Most patients treated by operation had an unsatisfactory result. Malunion was seen in 29% of the patients treated by closed means. The remaining ten patients had either severely comminuted (Type III), or pathological (Type IV) fractures. Intramedullary nail fixation should be used wherever possible in these fractures since many of the complications in the operative group were related to rigid plate fixation. Closed treatment resulted in an unacceptably high incidence of malunion in this study, particularly in Type I fractures. Conventional methods of internal fixation were not successful in dealing with Type II fracture, and alternative methods are proposed.

Effect on pancreatic blood flow and insulin output of infusions of aminophylline, galactose and galactose plus aminophylline into an isolated in situ portion of pancreas.

Effects on pancreatic blood flow and insulin output of infusions of aminophylline, galactose and galactose plus aminophylline were studied on an isolated portion of dog pancreas with only one afferent and one efferent blood vessel remaining. Infusion of aminophylline at 8 mg per minute gave significant increases in pancreatic blood flow and insulin output. Infusion of galactose at 7.2 mg per minute significantly increased insulin output. Galactose (7.2 mg per minute) plus aminophylline (8 mg per minute) also increased both pancreatic blood flow and insulin output. Pancreatic venous plasma glucose levels rose slightly during these infusions. Since the perfusing plasma contained a fasting level of glucose both aminophylling and galactose when infused alone or together were infused in the presence of approximately 1 mg/ml glucose. Pancreatic blood flow and insulin output increased to a lesser extent when aminophylline was infused along with galactose, the when aminophylline was infused alone.

Perturbations of humoral and cellular immunity in a patient with pigmented villonodular synovitis.

Several parameters of the immune system have been studied in a patient with pigmented villonodular synovitis. Numerous immunoglobulin-synthesizing cells were found by immunofluorescent technics in both synovium and synovial fluid. Phytohemagglutinin-induced in vitro blastogenesis of peripheral blood T lymphocytes was absent whereas B-lymphocyte blastogenesis was preserved. These results indicate a necessity for evaluating immune responsiveness in other patients with pigmented villonodular synovitis.

Development of pathways of insulin secretion in the rabbit.

Insulin release was studied in vitro using pieces of pancreas from rabbits of between 24 days gestational age and 6 weeks postnatal age. When allowance was made for the fraction of pancreas which was endocrine, 16-5mM-glucose caused increasing stimulation of insulin release as development advanced and 3-3 mM-glucose caused a similar rate of secretion at all ages. Secretion was not significantly influenced by insulin destruction in the incubation medium. Glucagon (5 mug/ml) did not stimulate insulin secretion from 24-day foetal pancreas but did so postnatally. Theophylline (1 mmol/1) stimulated insulin release at all ages and was equipotent on 24-day foetal pancreas in 3-3 or 16-5 mM-glucose. The stimulation of insulin release from 24-day foetal pancreas by 1 mM-theophylline occurred in the absence of extracellular glucose, pyruvate, fumarate and glutamate and in the presence of mannoheptulose and 2-deoxyglucose (each 3 mg/ml). Adrenaline (1 mumol/1) and diazoxide (250 mug/ml) abolished or attenuated the stimulation of insulin release by glucose, leucine plus arginine or theophylline from 24-day foetal, 1 day and 6 weeks postnatal pancreas. The stimulation of insulin release from 6-week-old pancreas by 1mM-barium was blocked by adrenaline and diazoxide but the effect became less with increasing immaturity. The experimental results illustrate some of the ways in which insulin secretion by the rabbit beta cell changes as a function of development and draw attention to the importance of glucose and cyclic adenosine monophosphate in this process.