Autofluorescence microscopy as a non-invasive probe to characterize the complex mechanical properties of keratin-based integumentary organs: A feather paradigm.

Integumentary organs exhibit diverse morphologies and functions. The complex mechanical property of the architecture is mainly contributed by the ingenious multiscale assembly of keratins. A cross-scale characterization on keratin integration in an integument system will help us understand the principles on how keratin-based bio-architecture are built and function in nature. In this study, we used feather as a model integument organ. We develop autofluorescence (AF) microscopy to study the characteristics of its keratin assemblies over a wide range of length scales. The AF intensity of each feather component, following the hierarchy from the rachis to barb to barbule, decreased with the physical dimension. By combining the analysis of AF signal and tensile testing, we can probe regional material density and the associated mechanical strength in a composite feather. We further demonstrated that the AF micro-images could resolve subtle variations in the defective keratin assembly in feathers from frizzled chicken variants with a mutation in α-keratin 75. The distinction between AF patterns and the morphological features of feather components across different length scales indicated a synergetic interplay between material integration and complex morphogenesis during feather development. The work shows AF microscopy can serve as an easy and non-invasive approach to study multiscale keratin organizations and the associated bio-mechanical properties in diverse integumentary organs. This approach will facilitate our learning of many bio-inspired designs in diverse animal integumentary organs/appendages.

Susceptibility-weighted imaging in patients with pyogenic brain abscesses at 1.5T: characteristics of the abscess capsule.

BACKGROUND AND PURPOSE: SWI is a high-resolution 3D, fully velocity-compensated gradient-echo sequence that uses both magnitude and phase data. The purpose of this study was to investigate the phase behavior of the capsule of pyogenic brain abscesses with noncontrast SWI. MATERIALS AND METHODS: Fourteen patients with pyogenic brain abscesses were studied at 1.5T. In all of the patients, SWI images were obtained and reviewed in addition to conventional MR images. Phase values within the abscess capsule were measured and compared with those from the abscess cavities and contralateral normal white matter using 1-way repeated measures ANOVA with post hoc Bonferroni analysis. RESULTS: SWI phase images showed mild hypointesity in 6 patients, isointensity in 3 patients, and mixed iso- to mild hypointensity in 5 patients. The means of phase in the cavity, rim of abscesses, and contralateral normal white matter were -7.552 × 10(-3) ± 0.024, -0.105 ± 0.080, and +0.029 ± 0.011 radians, respectively. Post hoc comparisons showed significant differences between any pair of the 3 regions (abscess cavity, rim capsule, and normal white matter) in SWI (all Ps < .005). CONCLUSIONS: SWI phase imaging shows evidence of paramagnetic substances in agreement with the presence of free radicals from phagocytosis. SWI may provide additional information valuable in the characterization of pyogenic brain abscesses.

Characterizing the three-dimensional organization of telomeres.

BACKGROUND: Quantitative analysis can be used in combination with fluorescence microscopy. Although the human eye is able to obtain good qualitative results, when analyzing the spatial organization of telomeres in interphase nuclei, there is a need for quantitative results based on image analysis. METHODS: We developed a tool for analyzing three-dimensional images of telomeres stained by fluorescence in situ hybridization in interphase nuclei with DNA counterstained with 4',6-diamidino-2-phenylindole. After deconvolution of the image, we segmented individual telomeres. From the location of the telomeres we derived a distribution parameter rhoT, which indicated whether the telomeres were in a disk (rhoT >> 1) or not (rhoT approximately 1). We sorted mouse lymphocyte nuclei and measured rhoT. We also performed a bromodeoxyuridine synchronous cell sorting experiment on live cells and measured rhoT at several instances. RESULTS: Measuring rhoT for nuclei in G0/G1, S, and G2 produced 1.4 +/- 0.1, 1.5 +/- 0.2, and 14 +/- 2, respectively, showing a significant difference between G2 and G0/G1 or S. For the bromodeoxyuridine synchronous cell sorting experiment, we found a cell cycle dependency of rhoT and a correlation between rhoT and an observer. CONCLUSIONS: In this study we present a quantitative method to characterize the organization of telomeres using three-dimensional imaging, image processing, and image analysis.

Simultaneous capture of metal, sulfur and chlorine by sorbents during fluidized bed incineration.

Metal capture experiments were carried out in an atmospheric fluidized bed incinerator to investigate the effect of sulfur and chlorine on metal capture efficiency and the potential for simultaneous capture of metal, sulfur and chlorine by sorbents. In addition to experimental investigation, the effect of sulfur and chlorine on the metal capture process was also theoretically investigated through performing equilibrium calculations based on the minimization of system free energy. The observed results have indicated that, in general, the existence of sulfur and chlorine enhances the efficiency of metal capture especially at low to medium combustion temperatures. The capture mechanisms appear to include particulate scrubbing and chemisorption depending on the type of sorbents. Among the three sorbents tested, calcined limestone is capable of capturing all the three air pollutants simultaneously. The results also indicate that a mixture of the three sorbents, in general, captures more metals than a single sorbent during the process. In addition, the existence of sulfur and chlorine apparently enhances the metal capture process.

A patient of primary hyperparathyroidism with full-blown bone changes simulating malignancy.

The two most common causes of hypercalcemia are malignancy and primary hyperparathyroidism (1 degree HPT). The radiographic presentations and the histological findings on bone biopsy are important for differential diagnosis of underlying diseases. We report a patient with hypercalcemia who presented unusual bone manifestations. A 43 y/o woman was admitted due to right femoral fracture. X-ray on the right tibia revealed several osteolytic cystic lesions with sclerotic rims. Blood biochemistry showed anemia, impaired renal function and hypercalcemia. Multiple osteolytic lesions on the skull and bilateral forearms were also noted. Malignancy, such as multiple myeloma or metastatic cancer was suspected. However, this was excluded because of the absence of M-component on serum protein electrophoresis and the negative finding of plasma cells or other malignant cell on bone biopsy examination. Abdominal sonography demonstrated bilateral medullary nephrocalcinosis. The final diagnosis of 1 degree HPT was made, based on the findings of classic pathological pictures (brown tumor) and the markedly elevated intact parathyroid hormone (1267.4 pg/ml) level. Sonography on the neck and 201Tl/99mTc parathyroid subtraction scan localized a left lower parathyroid tumor and fine needle aspiration confirmed the parathyroid origin. Diagnosis of 1 degree HPT could only be made from recurrent urolithiasis and X-ray picture of osteitis fibrosa cystica in the past. This patient presented the full-blown skeletal changes which are uncommonly seen nowadays. The characteristic sclerotic rims suggesting increased bone formation provides a further important clue for differential diagnosis of 1 degree HPT from other malignancies with osteolytic bone lesions.

In vitro gene transfer in mammalian cells via a new cationic liposome formulation.

A new cationic liposome formulation of sphingosine (SP) and dioleoylphosphatidylethanolamine (DOPE) was developed as an efficient transfection reagent. This SP/DOPE liposome showed efficient transfection in a wide variety of mammalian cancer cells. No significant cytotoxicity of the SP/DOPE liposome to cells was observed. The tranfection activity was greater than that of a well-reported liposome which was made from a cholesterol derivative 3beta-[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and the neutral lipid DOPE. In addition, the SP/DOPE liposome was found to be less toxic to cells than the DC-Chol/DOPE liposome. Stable transfections mediated by SP/ DOPE liposome were also demonstrated. These results suggest that the SP/DOPE liposome may provide a good gene delivery system to be used in the human cancer gene therapy.

The N-terminal 178-amino-acid domain only of the SV40 large T antigen acts as a transforming suppressor of the HER-2/neu oncogene.

The deregulation of the HER-2/neu protooncogene was demonstrated in a wide variety of human cancers and shown to be correlated with the progress of malignancy and metastasis in animal models. Repression of HER-2/neu overexpression suppressed the malignant phenotypes of HER-2/neu-overexpressing cancer cells. This suggested that HER-2/neu may be a good target for developing anti-cancer drugs. We found a deletion mutant of simian virus 40 (SV40) large T antigen (LT) suppresses the HER-2/neu oncogene expression at the transcriptional level. PCR clones of this mutant SV40LT, named LT425, which contains the N-terminal region of amino acid residues 1-178 of SV40LT, were subcloned and stably transfected into the HER-2/neu-overexpressing human ovarian cancer SKOV3.ip1 cells. These LT425 clones were found to be able to down-regulate the endogenous production of p185(HER-2/neu). In addition, the LT425-expressing stable transfectants showed reduced growth rate, low soft agarose colony forming ability, and low tumorigenic potential as compared with the parental line. These data suggested that the N-terminal 178 amino acids domain only of SV40LT may act as a transforming repressor of HER-2/neu oncogene.

Chromatographic and spectroscopic assignment of thiol induced cycloaromatizations of enediyne in neocarzinostatin.

Neocarzinostatin is an enediyne antitumor antibiotic. Upon attack by a thiol, the enediyne nucleus is cycloaromatized into two stable 1:1 thiol adducts. After analyzing products from various thiols, the chromatographic and spectroscopic characters that associate only with the cyclized aromatic moiety from enediyne nucleus were assigned. Based on HPLC analysis we have derived, products from picomole ranges of the drug sample can be detected. Confirming the type of cycloaromatization at nanomole ranges can be achieved by photodiode array UV spectroscopy. Three-dimensional fluorogram presents ten times more sensitive identification. The method provides a sensitive tool for massive screening study in microscale.

Spontaneous intestinal carcinomas and skin neoplasms in Msh2-deficient mice.

Hereditary nonpolyposis colorectal cancer is associated with defects in DNA mismatch repair. Here, we characterize tumor susceptibility of the recently described Msh2-deficient mouse model. Within the first year of observation, all homozygous mice succumbed to disease, with lymphomas observed in at least 80% of the cases. The majority (70%) of animals 6 months or older developed intestinal neoplasms associated with APC inactivation. Microsatellite instability was more common in carcinomas than in adenomas, but uncommon in normal tissues. Some animals (7%) developed a variety of skin neoplasms analogous to the Muir-Torre syndrome. Msh2-/- mice implicate a direct role for mismatch repair in several neoplasms with striking phenotypic similarities to humans.