Human BioSystems Affirms Donor Organ Preservation Results and Exceeds Current Standards.

PALO ALTO, Calif. -- (OTCBB:HBSC)-Human Biosystems announces today positive test results affirming its proprietary "HBS" organ preservation solution. On April 5, 2005, the Company reported that its HBS preservation solution compared favorably in lab results against UW and HTK- the current organ preservation solutions on the market. The HBS solution was tested against the UW and HTK solutions using animal kidneys for 36-40 hours, at 4 degree Centigrade (slightly above the freezing point of water). According to a performance rating index developed by the company referred to as "Reperfusion Index" (RPI) grading, a comparison of the tested animal kidneys affirmed the viability of organs stored in the HBS preservation solution.

"The RPI results are now further corroborated by examination of the histopathology samples, where cross-sections of the kidney were prepared and examined microscopically," said Dr. Luis Toledo, Chief Medical Officer for HBS.

"The findings show, for example, that the HTK-solution exhibited relatively larger areas of injury, described in scientific terms as vacuolization as well as tubular necrosis and picnotic nuclei. In contrast, the Company's HBS preservation solution produced smaller zones of injury accompanied by larger areas of normal tissue, and minimal tubular necrosis; in general, relatively better preserved structures were achieved in the comparative testing. This includes the Bowman's capsule and the convoluted tubular structures, all of which are essential to the normal functioning of the kidney," continued Toledo.

"We believe that the results that we have attained to date represent strong validation of our effort to extend the storage times of donor organs. The rat model used in our experiments is very sensitive and may often exhibit damage at 30 hours that is equivalent to damage in other animal models such as the pig, dog or human kidney stored longer than 40 hours. This could explain the damage observed with rat kidneys stored in the UW and HTK solutions for 40 hours, while human kidneys can be stored for up to 36 to 40 hours prior to transplantation in those solutions, and can be tolerated relatively well", said Dr. Fernando Lopez, Senior Research Scientist and transplant surgeon at HBS.

"While we plan to continue our above-freezing tests with this and other animal models, the Company has made a strategic decision to now shift its emphasis to the freezing technology also under development as the primary method to extend storage times for organs," according to company CEO, Harry Masuda.

Masuda went on to say that "We have learned from our research to date and are ready to proceed to the next step, and that is the possibility of highly prolonged preservation of donor organs through freezing. We believe that our freezing technology opens up many possibilities for not only donor organ preservation, but also for all of medical science."

HBS is headquartered in Palo Alto, California with research facilities in Michigan, www.humanbiosystems.com.

Certain statements contained herein are ``forward-looking'' statements (as such term is defined in the Private Securities Litigation Reform Act of 1995). Because such statements include risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Factors that could cause results to differ materially from those expressed or implied by such forward-looking statements include, but are not limited to, results from ongoing research and development as well as clinical studies, failure to obtain regulatory approval for the Company's products, if required, failure to develop a product based on the Company's technology, failure of any such products to compete effectively with existing products, the ability of the Company to fund marketing and sales efforts that may be required to effectively sell its products .and other factors discussed in filings made by the Company with the Securities and Exchange Commission.

Human BioSystems (OTC Bulletin Board:HBSC)