skip navigation nih record
Vol. LXI, No. 19
September 18, 2009
cover

previous story

next story


Digest

NIBIB Scientists Combine Microscopy Methods to Increase Imaging Efficiency in Cell Structure Studies

Scientists in the National Institute of Biomedical Imaging and Bioengineering’s Laboratory of Bioengineering and Physical Science have developed a new technique that allows researchers to visualize fine details of cell structure 3-dimensionally in thick sections, thus providing greater insight into how cells are organized and how they function. The work is described in a report published online Sept. 3 in Nature Methods.

The new electron tomography method, referred to as BF STEM tomography, lets researchers image samples that are more than three times the thickness of typical samples.

Electron tomography is carried out at the nanoscale on individual cells. Conventionally, high-resolution imaging of biological specimens has been accomplished by cutting cells into thin sections (300 nanometers or less) and imaging each section separately. Although reconstructing an entire structure from thin sections is laborious, thin sections are used because images of thicker sections typically are blurred. Serial BF STEM tomography accomplishes the same work using fewer yet thicker specimen sections, leading to faster reconstruction of intact organelles, intracellular pathogens and even entire mammalian cells.

Drs. Alioscka Sousa, Martin Hohmann-Marriott, Richard Leapman and colleagues in NIBIB, in collaboration with Dr. Joshua Zimmerberg and colleagues at NICHD, demonstrated feasibility and advantages of BF STEM tomography in a study of red blood cells. High-resolution 3D reconstructions of entire cells were generated by serially imaging just a few thick sections. The intricate system of red blood cell and parasite membranes, as well as several organelles, can be seen in detail.

MicroRNAs in Blood May Be Biomarkers of Pancreatic Cancer

Small molecules known as microRNAs, which can be detected in blood samples, have the potential to help identify patients with pancreatic cancer, an NCIsupported study finds.

Small molecules known as microRNAs, which can be detected in blood samples, have the potential to help identify patients with pancreatic cancer, a study finds. The study, by researchers at the University of Texas M.D. Anderson Cancer Center in Houston, was supported by the Early Detection Research Network of the National Cancer Institute. The paper appeared online Sept. 1 in Cancer Prevention Research.

Pancreatic cancer is a highly fatal disease that is difficult to detect at early stages. In most patients, symptoms do not appear until the cancer is locally advanced or has spread to other parts of the body. The absence of symptoms in early-stage disease and the current lack of effective, minimally invasive screening and diagnostic techniques limit the available treatment options. Both contribute to the high mortality rate observed for patients with pancreatic cancer.

“The development of a minimally invasive test for the early detection and diagnosis of pancreatic cancer is greatly needed,” said Dr. Sudhir Srivastava of NCI’s Division of Cancer Prevention. “An important step is to identify biomarkers for pancreatic cancer, such as microRNAs, circulating in the bloodstream that can be used to distinguish individuals with pancreatic cancer from individuals without the disease.”

 

Studies in Animals Suggest 2009 H1N1 Virus May Have Biological Advantage Over Seasonal Influenza Viruses

Preliminary findings in ferrets suggest that the novel 2009 H1N1 influenza virus may outcompete human seasonal influenza viruses, researchers say. Tests in animals showed that levels of the 2009 H1N1 virus rose more quickly than levels of the seasonal virus strains, and the new virus caused more severe disease. In line with previous findings by other research groups, the University of Maryland researchers also observed that the novel H1N1 virus was transmitted more easily from infected to uninfected ferrets than either of the two seasonal influenza viruses.

The researchers found no evidence that the 2009 H1N1 virus combined with either of two seasonal flu viruses to form new, so-called reassortant viruses. These findings suggest that while 2009 H1N1 virus probably will predominate in the coming flu season, there may not be biological pressure for the new virus to recombine with other circulating viruses, the researchers say.

The work was done by Dr. Daniel Perez and colleagues from the University of Maryland and was supported by the National Institute of Allergy and Infectious Diseases. Results appeared in PLoS Currents: Influenza, a web site for rapid communication of new scientific data on influenza.

back to top of page