Health Scan: Looking sharply into the eyes

The recent innovation, described in Nature Publishing’s Light: Science & Applications, enables non-invasive two-photon imaging of mouse retinas.

By JUDY SIEGEL-ITZKOVICH
Updated: JANUARY 30, 2016 22:16
Eye exam [Illustrative] (photo credit: REUTERS)
Eye exam [Illustrative]
(photo credit: REUTERS)
Innovative imaging technology developed at the department of biomedical engineering at the Technion-Israel Institute of Technology in Haifa captures fine, high-quality optical images of retinal structures in vivo. The system, which can easily be integrated into any existing two-photon microscope without requiring adaptive corrections, could potentially be transformative for retina research.
The recent innovation, described in Nature Publishing’s Light: Science & Applications, enables non-invasive two-photon imaging of mouse retinas, said its developers at the Neural Interface Engineering lab, including doctoral student Adi Schejter Bar-Noam, lab head Prof. Shy Shoham and research associate Dr. Nairouz Farah. Thus it could therefore potentially transform eye research and our understanding of the mechanisms that underlie retinal physiology.
The study describes an optical system based on add-on optics that can be easily integrated into essentially any existing two-photon microscope and includes an electronically tunable lens for motionless scanning of the depth dimension.
The system’s simplicity effectively opens up a new range of potential applications for two-photon excitation microscopy – an advanced fluorescence imaging technique already installed today in numerous laboratories.
Two-photon microscopy provides fluorescence imaging with sub-cellular resolution, contributing to the understanding of cells and multicellular structures in biological tissues. The key advantage of this approach is its ability to penetrate relatively deeply into tissues, creating three-dimensional images consisting of a series of two-dimensional cross-sections.
This is what turned it in the last two decades into a principal tool in studies focusing on the structure and operation of the brain and nervous system. However, until now it was not harnessed for in vivo retinal imaging due to focusing constraints arising from the combination of common two-photon imaging lenses and the optics of the mouse eye.
Now, thanks to this novel technology, it is possible to image entire regions in the retina – including blood vessels and neurons – noninvasively and at high resolutions. Since the system uses near-infrared (NIR) lightbased two-photon excitation, the microscopic examination does not strongly impact the behavior of the imaged retina and allows it to “see” almost normally during imaging.
The researchers used this in order to directly measure in vivo natural neural responses to flashes of light for the first time.
“Our motivation in developing this new technology was for research purposes – to improve the methods available to us as scientists,” explained Schejter Bar-Noam who developed the system. “Perhaps in the future, the new system will accommodate the development of translational vision applications, although our current study was limited to researching the retina and its neurons. The system provides an advanced in vivo microscopic image of the living retina without causing it any damage; we confirmed that prolonged use of the system did not cause any damage to the examined retina.”
“The broader context of our work is optogenetics,” added Shoham, “a scientific area that has flourished over the past decade and allows us to study neurons over time using fluorescent proteins or to use light-sensitive proteins to activate cells. The new system allows us to make use of the two-photon microscope in both aspects, that is, in the imaging of retinal neurons or for cellular activation by light. Indeed, the extended design process demonstrated its effectiveness for imaging nerve cells and blood vessels.”

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DIALYSIS UNIT OPENS AT EIN KEREM
Hadassah University Medical Center in Ein Kerem, Jerusalem recently inaugurated a new dialysis unit. Located in the state-ofthe- art Davidson Tower, the unit will provide treatment for over 80 dialysis patients in the greater Jerusalem area, which will amount to over 1,000 dialysis treatments monthly. The unit will provide services as a community clinic, in addition to functioning as an active hospital unit for treatment of acute kidney problems.
Dialysis treatment removes waste and excess water from the blood, ultimately simulating kidney function in patients who are suffering from acute kidney issues or from kidney failure.
Ruthie Israeli, the unit’s head nurse, said: “Times have changed, technology has changed and the needs of the patients and medical staff have changed. Patients spend five hours per visit or 15 hours per week. The tremendous improvement of the facilities and the technology will ultimately lead to tremendous upgrading of the unit’s medical treatment.”
The inauguration of the new unit brings to a close of the Ziv Community Clinic, Hadassah’s dialysis unit that operated out of downtown’s Bikur Cholim Hospital for the past 22 years.
The Davidson Tower is equipped with advanced technology lab work can be done on-site with quick results, and patients can enjoy the upgraded amenities including WiFi and cable TV.