Growth of textured thin Au coatings on iron oxide nanoparticles with near infrared absorbance.

A homologous series of Au coated iron oxide nanoparticles with hydrodynamic diameters smaller than 60 nm was synthesized with very low Au-to-iron mass ratios, as low as 0.15. The hydrodynamic diameter was determined by dynamic light scattering and the composition by atomic absorption spectroscopy and energy dispersive x-ray spectroscopy. Unusually low Au precursor supersaturation levels were utilized to nucleate and grow Au coatings on iron oxide relative to the formation of pure Au nanoparticles. This approach produced unusually thin coatings by lowering autocatalytic growth of Au on Au, as shown by transmission electron microscopy. Nearly all of the nanoparticles were attracted by a magnet, indicating a minimal number of pure Au particles. The coatings were sufficiently thin to shift the surface plasmon resonance to the near infrared with large extinction coefficients, despite the small particle hydrodynamic diameters observed from dynamic light scattering to be less than 60 nm.

Serial factitious disorder and Munchausen by proxy in pregnancy.

Factitious disorder, including Munchausen syndrome, is seldom documented among pregnant patients but can have powerful consequences. We report on a 44-year-old woman who, over a period of two decades, self-induced labour and delivery in five consecutive pregnancies. She precipitated labour by rupturing her own amniotic sac with a fingernail or cervical manipulation, or misappropriating and self-administering prostaglandin suppositories from the hospital unit on which she worked as a nurse. Preterm deliveries resulted in fetal demise in one case and in neonatal intensive care treatment for two of the offspring. One of the surviving children has cerebral palsy attributable to the mother's factitious illness behaviour, which raises the spectre of Munchausen by proxy maltreatment. The patient sought attention and care through the ruses, which have never been uncovered by her obstetric and gynaecologic caregivers. Indeed, she underwent an unnecessary hysterectomy because of the illusion of heavy menstrual bleeding. Most recently, the patient has been engaging in surreptitious autophlebotomy to force blood transfusions.

Heart failure with a normal ejection fraction: is measurement of diastolic function necessary to make the diagnosis of diastolic heart failure?

BACKGROUND: The diagnosis of diastolic heart failure is generally made in patients who have the signs and symptoms of heart failure and a normal left ventricular (LV) ejection fraction. Whether the diagnosis also requires an objective measurement of parameters that reflect the diastolic properties of the ventricle has not been established. METHODS AND RESULTS: We hypothesized that the vast majority of patients with heart failure and a normal ejection fraction exhibit abnormal LV diastolic function. We tested this hypothesis by prospectively identifying 63 patients with a history of heart failure and an echocardiogram suggesting LV hypertrophy and a normal ejection fraction; we then assessed LV diastolic function during cardiac catheterization. All 63 patients had standard hemodynamic measurements; 47 underwent detailed micromanometer and echocardiographic-Doppler studies. The LV end-diastolic pressure was >16 mm Hg in 58 of the 63 patients; thus, 92% had elevated end-diastolic pressure (average, 24+/-8 mm Hg). The time constant of LV relaxation (average, 51+/-15 ms) was abnormal in 79% of the patients. The E/A ratio was abnormal in 48% of the patients. The E-wave deceleration time (average, 349+/-140 ms) was abnormal in 64% of the patients. One or more of the indexes of diastolic function were abnormal in every patient. CONCLUSIONS: Objective measurement of LV diastolic function serves to confirm rather than establish the diagnosis of diastolic heart failure. The diagnosis of diastolic heart failure can be made without the measurement of parameters that reflect LV diastolic function.

Doppler ultrasound imaging detects changes in tumor perfusion during antivascular therapy associated with vascular anatomic alterations.

Noninvasive monitoring of antiangiogenic therapy was performed by serial power Doppler ultrasound imaging of murine tumors treated with recombinant interleukin 12, the results of which were correlated with assessments of tumor vascularity by microscopy. Growth of established K1735 tumors, but not of IFN-gamma-unresponsive K1735.N23 variants, was suppressed by treatment. Serial Doppler imaging of K1735 tumor vascularity during treatment revealed a progressive change from a diffuse perfusion pattern to a more punctate distribution. Quantitative analysis of the images revealed that color-weighted fractional average, representing overall tumor perfusion, consistently decreased in these tumors, primarily because of a decrease in fractional tumor cross-sectional area carrying blood flow. In contrast, these parameters increased in nonresponsive tumors during treatment. Confocal microscopy of thick tumor sections revealed a reduction in the density and arborization of vessels labeled in vivo by fluorochrome-conjugated lectin with effective treatment. Immunohistological examination of thin tumor sections confirmed the preferential loss of small vessels with successful therapy. Similar changes in tumor vascular anatomy and perfusion were also observed during recombinant interleukin 12 treatment of two other responsive murine tumor types. These results indicate that power Doppler ultrasound is a sensitive, noninvasive method for reporting functional consequences of therapy-induced vascular anatomical changes that can be used to serially monitor tumor perfusion and efficacy of antivascular therapy in clinical trials.

A comparison of monopolar electrosurgery to a new multipolar electrosurgical system in a rat model.

OBJECTIVES/HYPOTHESIS: The purpose of this study is to compare collateral tissue damage and wound healing in incisions created by electro-dissociation and conventional electrosurgery. Conventional electrosurgery has been used as an alternative to the scalpel to improve hemostasis. However, the heat generated by this instrument can cause tissue damage surrounding the incision, limiting its use around nerves and large blood vessels. A new technology, Coblation (Arthrocare Corp., Sunnyvale, CA), uses "electro-dissociation" to achieve similar results by creating charged particles from a conductive medium to make an incision while simultaneously achieving hemostasis. This new approach to electrosurgery may reduce soft tissue damage. METHODS: Two prospective, matched design experiments were performed. In experiment I, both devices were set at the same electrical power in watts and then used to create an incision on the tongue of rats. In experiment II, the electrical power settings of both devices were adjusted until they created incisions of the same size. Epithelial destruction and collateral tissue damage were measured in histologically prepared tissue in both experiments, and the wound healing process was observed in experiment II at 0, 3, 7, and 14 days after surgery. RESULTS: The results showed that the electro-dissociation method created significantly less epithelial destruction and collateral tissue damage in both experiments. Granulation tissue formation was also significantly less extensive in the electrodissociation-induced incision after 7 and 14 days of recovery. CONCLUSIONS: Wound healing may be faster than with conventional electrosurgery if the Coblation device is used.

An explanatory model for Munchausen by proxy abuse.

OBJECTIVE: In Munchausen by proxy (MBP) abuse, a caretaker fabricates or induces illness in another person to obtain emotional gratification. In representative cases, a mother is the perpetrator and her child is the victim. In view of the limits of current explanatory models, we use personal accounts of MBP perpetrators, physicians, and family members as a window into understanding this counterintuitive behavior. METHOD: As subspecialty clinicians and consultants, we supplemented our extensive direct experience with MBP with a review of published reports of MBP located via MEDLINE and PsycINFO (1980 onward). We also examined the books devoted to the subject and incorporated personal accounts of MBP perpetrators and of family members and professionals involved with them. RESULTS: Factors contributing to the onset and continuation of MBP are the perpetrator's experiencing a particular drive (e.g., intense anger or frustration); lacking or overcoming internal inhibitions against abusive actions; and overcoming external inhibitions, such as the potential intercession of a spouse or pediatrician. As a result, the MBP parent experiences release from unpleasant emotions and a sense of renewed control. MBP behavior gains "habit strength" each time it occurs. CONCLUSIONS: Psychodynamic explanations of MBP, while favored by some authors, are inherently speculative and tend to be low in predictive value. We suggest broadening these traditional explanations by emphasizing observable behaviors and verifiable background factors. The behavioral perspective we outline helps explain how MBP behavior is learned, why it is more prevalent among mothers, and why it is so difficult for perpetrators to stop.

Validation of a mouse conductance system to determine LV volume: comparison to echocardiography and crystals.

The application of left ventricular pressure-volume analysis to transgenic mice to characterize the cardiac phenotype has been problematic due to the small size of the mouse heart and the rapid heartbeat. Conductance technology has been miniaturized for the mouse and can solve this problem. However, there has been no validation of this technique. Accordingly, we performed echocardiography followed by simultaneous ultrasonic crystals, flow probe, and conductance studies in 18 CD-1 mice. Raw conductance volumes were corrected for an inhomogenous electrical field (alpha) and parallel conductance (G(pi)) yielding a stroke volume of 14.1 +/- 3.7 microliter/beat, end-diastolic volume of 20.8 +/- 6.5 microliter, and end-systolic volume of 9.0 +/- 5.8 microliter. The mean conductance volumes were no different from those derived by flow probe and echocardiography but did differ from ultrasonic crystals. G(pi) was determined to be 14.9 +/- 8.7 microliter. However, hypertonic saline altered dimension and pressure in the mouse left ventricle. Although G(pi) can be determined by the hypertonic saline method, saline altered hemodynamics, questioning its validity in the mouse. Although mean measures of absolute volume may be similar among different techniques, individual values did not correlate.