Biomedical subjects

Nan Zhang

Publications and source records attributed to Nan Zhang.

76 records · Page 5Linked to original sources

PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗

PubMedDate not supplied

Liquid chromatography MALDI MS/MS for membrane proteome analysis.

Membrane proteins play critical roles in many biological functions and are often the molecular targets for drug discovery. However, their analysis presents a special challenge largely due to their highly hydrophobic nature. We present a surfactant-aided shotgun proteomics approach for membrane proteome analysis. In this approach, membrane proteins were solubilized and digested in the presence of SDS followed by newly developed auto-offline liquid chromatography/matrix-assisted laser desorption ionization (LC/MALDI) tandem MS analysis. Because of high tolerance of MALDI to SDS, one-dimensional (1D) LC separation can be combined with MALDI for direct analysis of protein digests containing SDS, without the need for extensive sample cleanup. In addition, the heated droplet interface used in LC/MALDI can work with high flow LC separations, allowing a relatively large amount of protein digest to be used for 1D LC/MALDI which facilitates the detection of low abundance proteins. The proteome identification results obtained by LC/MALDI are compared to the gel electrophoresis/MS method as well as the shotgun proteomics method using 2D LC/electrospray ionization MS. It is demonstrated that, while LC/MALDI provides more extensive proteome coverage compared to the other two methods, these three methods are complementary to each other and a combination of these methods should provide a more comprehensive membrane proteome analysis.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Interactive stereoscopic rendering of volumetric environments.

We present an efficient stereoscopic rendering algorithm supporting interactive navigation through large-scale 3D voxel-based environments. In this algorithm, most of the pixel values of the right image are derived from the left image by a fast 3D warping based on a specific stereoscopic projection geometry. An accelerated volumetric ray casting then fills the remaining gaps in the warped right image. Our algorithm has been parallelized on a multiprocessor by employing effective task partitioning schemes and achieved a high cache coherency and load balancing. We also extend our stereoscopic rendering to include view-dependent shading and transparency effects. We have applied our algorithm in two virtual navigation systems, flythrough over terrain and virtual colonoscopy, and reached interactive stereoscopic rendering rates of more than 10 frames per second on a 16-processor SGI Challenge.

Algorithms↗

PubMedDate not supplied

Pattern of inflammation and impact of Staphylococcus aureus enterotoxins in nasal polyps from southern China.

BACKGROUND: This study analyzes the impact of Staphylococcus aureus enterotoxins (SAEs) and the inflammatory pattern in polyps from China. METHODS: Nasal tissue was obtained from 27 consecutive bilateral nasal polyps and 15 control patients and assayed for eotaxin, interleukin-5, soluble interleukin-2 receptor, transforming growth factor (TGF) beta, myeloperoxidase, eosinophil cationic protein, total IgE, and specific IgE to SAEs. Activated eosinophils were stained using EG2 antibodies in polyps from Chinese and comparative white patients. RESULTS: The number of EG2+ eosinophils was significantly lower in polyps from Chinese patients versus white patients. Chinese polyps showed significantly increased IgE and soluble interleukin-2 receptor versus control samples, whereas TGF-beta1 was significantly decreased. Ten of 27 samples in the polyp group versus 0 of 15 controls contained SAE-IgE (p < 0.01). TGF-beta1 was significantly down-regulated in SAE+ samples versus SAE- samples (p = 0.04). CONCLUSION: Nasal polyps from China are characterized by B- and T-cell activation, a minor eosinophilic inflammation compared with polyps from white subjects, and a decrease in TGF-beta1 in comparison with control inferior turbinate tissue. One-third of patients with polyps showed an IgE response to SAEs.

Adolescent↗