Mad cow-resistant cattle developedNEW YORK (Reuters Health) — By genetically removing a particular protein, scientists have developed cattle that seem to be resistant to mad cow disease, according to a report in the journal Nature Biotechnology.Dr. Juergen A. Richt with the United States Department of Agriculture in Ames, Iowa and colleagues generated cattle lacking the prion protein (PrP) and monitored them for growth and general health status from birth to 20 months of age.

PrP in its normal formation does not cause disease in cattle, but when it takes on a configuration containing misfolds, it results in mad cow disease, also known as bovine spongiform encephalopathy.

Because the function of the normal PrP is not clear, it was not known if animals without this protein would be healthy.

To investigate, Richt’s group first developed mice lacking the gene for PrP. No growth or developmental abnormalities were seen. Next, they moved on to cattle. The animals also displayed normal growth and development and had no abnormal blood tests, the researchers note.

Early tests suggested that these animals are resistant to the development of mad cow disease. The authors note, however, that full testing will take at least three years.Prostate treatment may shorten penisNEW YORK (Reuters Health) — Men who receive combination treatment with hormone therapy plus radiation for local or locally advanced prostate cancer may experience a significant reduction in penile length, according to a report in the January issue of the Journal of Urology.There has been anecdotal evidence that radiation therapy can reduce penile length but, to the authors’ knowledge, the present study is the first to determine if penile length changes following combination treatment with hormone therapy plus radiation.

Dr. Ahmet Haliloglu and colleagues at the University of Ankara in Turkey enrolled 47 men with local or locally advanced prostate cancer.

The patients, who were followed from 2000 to 2005, received leuprolide or goserelin injections every three months, for a total of three doses.

At month seven, radiotherapy, using a 70-Gy dose, was initiated and continued for seven weeks.

Just before treatment began, the average stretched penile length was 5.6 inches.

Eighteen months later, the average penile length had shortened significantly to 3.4 inches.

Erectile function was also adversely affected by treatment. Roughly 23 percent of men had normal erectile function before therapy. Eighteen months later, 12.5 percent were able to have an erection that was suitable for intercourse.

“Quality of life concerns are important when considering treatment options for prostate cancer,” the investigators conclude. Before starting combination hormone and radiation therapy, the patient should be told that “penile shortening may occur.”