CT of appendicitis in children

PURPOSE: Our goal was to review the CT findings and to help define the role of CT in the evaluation of appendicitis in children. METHOD: Of 730 children with surgically proven appendicitis, 22 underwent preoperative CT evaluation. Their CT scans and operative and pathology records were retrospectively reviewed. The CT scans were evaluated for appendiceal wall thickness, diameter, and location, appendicoliths, pericecal inflammation, phlegmon, abscess, free fluid, small bowel dilatation, and bowel wall thickening. Criteria for diagnosing appendicitis were (a) appendiceal wall thickening (> 1 mm) or (b) presence of abscess, phlegmon, or pericecal inflammation associated with appendicolith(s). Prospective reports of ultrasound examinations performed within 2 days of the CT scans were available in 14 children and were correlated with the CT findings. RESULTS: An abnormally thickened appendix, with a diameter ranging from 9 to 18 mm, was seen in four children. Three appendices were retrocecal and one was near the cecal tip, anterior to the iliac vessels. Appendicoliths were present in 10 children, multiple in 1. Abscesses were seen in 13 of 22 children, multiple in 5. Phlegmon was seen in five children and pericecal inflammation in two. Bowel wall thickening was present in seven children and small bowel dilatation was noted in six. Other findings included free fluid, hydronephrosis, thickening of urinary bladder wall, air in the uterus and vagina, adenopathy, and thickening of the abdominal wall musculature. CT was diagnostic of appendicitis in 11 of 22 children (50%). In 14 children with both ultrasound and CT studies, CT was slightly better in diagnosing appendicitis and visualizing the abnormal appendix and was superior in defining the presence and extent of abscess and inflammation in 9 of 14 children. CONCLUSION: CT is a useful adjunct in diagnosing appendicitis in children, with a major role in cases of complicated appendicitis.     

Plasmid DNA is protected against ultrasonic cavitation-induced damage when complexed to cationic liposomes

Cationic liposomes bound to plasmid DNA are currently used for in vitro and in vivo gene therapy applications, but such complexes readily form large, heterogeneous aggregates that are not appropriate for pharmaceutical development. More importantly, size heterogeneity makes studies focused on optimizing gene transfer to cells difficult to conduct or understand. For this reason we have evaluated the effect of microprobe sonication on these complexes in an effort to achieve process-controlled size homogeneity. Complexes were prepared using a 7.2 kb reporter plasmid and the following liposomal lipid combinations: DDAB/DOPE (50:50 mol %), DDAB/DOPE/PEG-PE (50:45:5 mol %), DDAB/EPC (50:50 mol %), DDAB/EPC/PEG-PE (50:45:5, 50:40:10, 50:35:15 mol %), DODAC/DOPE (50:50 mol %), and DODAC/EPC (50:50 mol %) (DDAB, dimethyldioctadecylammonium bromide; DOPE, dioleoylphosphatidylethanolamine; PEG-PE, monomethoxypolyethylene glycol2000 succinate- distearoylphosphatidylethanolamine; EPC, egg phosphatidylcholine; DODAC, dioleoyldimethylammonium chloride). The influence of complex composition and lipid:DNA ratio was evaluated. Particle size was determined before and after complexation and again after sonication using the quasi-elastic light scattering technique. DNA integrity was assessed via agarose gel electrophoresis. Finally, gene transfection was evaluated using CHO cells that were transfected in vitro with sonicated and unsonicated complexes. It is established in this study that size reduction can occur, but this is dependent on cationic and neutral lipid composition and, in some cases, lipid:DNA ratio. Surprisingly, the process of sonication leaves a significant percentage of the plasmid DNA intact and capable of in vitro transfection. This study shows that plasmid DNA can be protected from damage due to sonication by liposome complex formation. This may indicate that more common pharmaceutical methods for size reduction which subject particles to mechanical stress may be applicable in preparation of liposome/DNA formulations for in vivo application.     

Improved accuracy of burn wound assessment using laser Doppler

The utility of the laser Doppler for determining burn depth has been questioned because of problems with technology and methodology. This study prospectively evaluates the ability of a new laser Doppler technique to predict burn healing time. Using the Periflux System 4000 laser Doppler, readings were taken on 305 burns (147 patients) on postburn day 3 or 4. Sixty-six wounds were used to derive a predictive function (phase I) and 152 wounds were used to test the function (phase II). Blood flow dynamics (flux), microvascular dilation capacity of the wounds to beat stress, and flow motion wave pattern (vasomotion) were studied using the laser Doppler, and seven parameters were evaluated to determine their relative contribution to the prediction of healing time. These parameters are hyperemic flux (flux value after heating to 42 degrees C), average hyperemic wave amplitude (AHWA), number of average flux units >100(F100), number readings with wave amplitude 75 (A5), average flux change (AFC), percentage of average flux increase, and relative flow capacity (RFC = AFC/average hyperemic flux). After readings were made, the wounds were observed and divided into two groups: those that healed in less than 14 days and those that healed or were grafted after 14 days. A step-wise discriminant analysis was used to assess the relative contribution of the Doppler-derived measures to healing time prediction. AHWA, F100, and RFC were included in the final discriminant function explaining 72% of the healing time variance (Wilks' lambda value 0.28; p value <0.0001). Predicted outcome = 0.05(AHWA) + 0.31(F100) + 5.0(RFC) - 2.3. With this derived function, there is 94% accuracy in the prediction of burn wound healing time compared with a physician predictive accuracy of 70%.     

Paget's disease of the breast in a man without underlying breast carcinoma

A case of histologically confirmed Paget's disease of the breast in a 72 year old man, without underlying breast carcinoma, is reported. This report raises questions about the pathogenesis of this condition and suggests that Paget's disease is an independent, intraepidermal carcinoma rather than a direct extension of intraductal carcinoma of the breast to the nipple and areola.     

Methods used in dentin bonding tests: an analysis of 50 investigations on bond strength

Researchers have carried out a variety of investigations to determine the properties of available dentin bonding systems. The test methods and variables used in 50 published investigations of bond strength were analyzed. Among the studies analyzed, shear tests predominated, being used in 80% of the studies; dentin from human molar teeth was used most often (in 88% of investigations); and the most prevalent time of testing was 24 hours postcuring. However, a number of potential variables were not recorded in a high proportion of articles, among these the film thickness, the type of dentin tested, and the surface condition (moist or dry). The mode of failure was recorded in only 42% of the investigations assessed. It was found that there is little standardization of test methods in studies of dentin bond strength and that a number of variables are often either not recorded or reported.     

Vertebral artery trauma

The developmental consequences of paternal exposure to acrylamide (50 mg/kg i.p. for 5 days) were assessed in preimplantation embryos. There was a significant increase in the proportion of morphologically abnormal embryos after postmeiotic treatment during spermatogenesis (88.7% vs. 14.8% in control). Abnormal embryos had an average of 1.8 +/- 3.5 cells and > 80% had at least one fragmented nucleus. In addition, morphologically normal embryos were significantly delayed (34.3 +/- 12.8 cells per embryo vs. 57.6 +/- 15.7 in control, P < 0.001). Acrylamide caused 10- and 20-fold increases in frequencies of cells with micronuclei (MN) in morphologically normal and abnormal embryos, respectively (41 and 93 MN per 1,000 cells). Both centromere-negative (MN-) and centromere-positive (MN+) were induced. Nuclei of abnormal embryos were significantly larger (900 microm2 vs. 250 microm2) than controls. In addition, MN of abnormal embryos were larger than those of normal embryos (21.2 microm2 vs. 6.5 microm2, P < 0.01). Among control embryos, MN+ were significantly larger than MN- (P < 0.05). These findings suggest that the preimplantation embryo is a sensitive indicator of paternally transmitted effects on early development. Multiple mechanisms appear to be involved, including cytogenetic damage, proliferation arrest/delay, and fertilization failure. Future studies are needed to establish how induced cytological defects in preimplantation embryos contribute to birth defects and other postimplantation abnormalities.     

A high-current and high-temperature 6H-SiC thyristor

A 6H-SiC thyristor has been fabricated and characterized. A forward breakover voltage close to 100 V and a pulse switched current density of 5200 A/cm² have been demonstrated. The thyristor is shown to operate under pulse gate triggering for turn-on and turn-off, with a rise time of 43 ns and a fall time of less than 100 ns. The forward breakover voltage is found to decrease by only 4% when the operating temperature is increased from room temperature to 300°C. It is found that anode ohmic contact resistance dominates the device forward drop at high current densities     

Why do semantic priming effects increase in old age? A meta-analysis.

Reports a meta-analysis comparing the size of semantic priming effects on young and older adults' lexical decision and pronunciation latency. The analysis included 15 studies with 49 conditions varying the semantic relatedness of a prime stimulus (single word or whole sentence) and a target word. An effect-size analysis on the difference between young and older adults' semantic priming effect (unrelated minus related latency) indicated that semantic priming effects are reliably larger for older than for young adults. There was no evidence for nonhomogeneity in this age difference across the different conditions. The relationship between young and older adults' semantic priming effects was described by a function with a positive intercept and a slope of 1.0. This pattern of findings favors aging models postulating process-specific slowing rather than general cognitive slowing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)