Alterations in vitamin D metabolism normally occur after the menopause and with aging. Increases in skeletal remodeling as a consequence of estrogen deficiency lead to increased bone resorption, suppression of serum 1,25-dihydroxy-vitamin D and intestinal absorption of calcium and increases in urinary calcium. Age-related changes in vitamin D metabolism include diminished dermal production of 7-dehydrocholesterol, the precursor of previtamin D(3), vitamin D deficiency as a consequence of inadequate intake or exposure to sunshine (individuals may be institutionalized or housebound), a decline in intestinal vitamin D receptors and diminished intestinal absorption of calcium and secondary hyperparathyroidism which leads to further bone loss. These changes also have been implicated in the pathogenesis of senile osteoporosis. Treatment with vitamin D and its analogues such as 1,25-dihydrox-yvitamin D(3 )is sometimes of value in preventing bone loss and fractures in patients with postmenopausal osteoporosis and senile osteoporosis. However, the drugs have not been approved for treatment and prevention of osteoporosis.

Journal Article↗

PubMedDate not supplied

Survey of fresh vegetables for nematodes, amoebae, and Salmonella.

Contamination by nematodes, amoebae, and bacteria of the genus Salmonella was estimated in a 2-year survey of salad vegetables obtained from wholesale and retail sources. The vegetables examined were cucumbers, cabbage, lettuce, celery, carrots, radishes, tomatoes, mushrooms, cauliflower, and spinach. Nematode eggs and larvae were recovered by the Nacconol-ether centrifugation method. Some nematode eggs were identified as parasitic Ascaris sp.; the majority of larval nematodes were thought to be soil-dwelling species. Amoebae were recovered by rinsing the vegetables with distilled water, centrifuging the rinse water, and transferring the sediment to agar plates on which a bacterial lawn had previously been grown; trophozoites identified as the potentially pathogenic species--Acanthamoeba polyphaga, A. rhysodes, and A. castellanii--were the most common amoebae recovered on the plates. Salmonella spp. were grown from 4 of 50 samples.

Amoeba↗