PubMed HealthSearch

Biomedical subjects

T Cojocaru

Publications and source records attributed to T Cojocaru.

3 recordsLinked to original sources

Image-guided stereotactic surgery: a 10-year evolutionary experience.

The recent revolution in medical imaging has demanded concurrent development of sophisticated and compatible stereotactic guiding devices in order to diagnose or treat mass lesions on the brain and disorders of cerebral physiology. Between July 1, 1979, and July 1, 1989, 1,006 patients underwent image-guided stereotactic surgery at the University of Pittsburgh. During this 10-year interval the first dedicated computed tomography stereotactic operating room and the first North American radiosurgical suite containing a 201 60Co source gamma knife were constructed. Early in our experience, 60.5% of the patients underwent diagnostic (biopsy) stereotactic surgery whereas, by 1988, 77.8% of the patients underwent therapeutic stereotactic surgery. At our institution, stereotactic surgery was performed last year in 257 patients, representing 19.9% of all neurosurgical operations. During the past 10 years, stereotactic surgery has developed an integral and definitive role in contemporary mainstream neurosurgery. Across the world stereotactic technology is now widely available. In the future increasing emphasis will be placed on therapy, image integration, computer software development, and new instrumentation designed to meet the evolving needs of neurological surgeons who demand safe, precise, and effective tools to explore the brain.

Biopsy

24,25(OH)2D3 attenuates the calcemic effect of 1,25(OH)2D3 in rats with reduced renal mass.

The present study was undertaken to evaluate the effect of 24,25(OH)2D3 on serum calcium concentration in rats with reduced renal mass. Adult 5/6 nephrectomized male rats were divided into four groups: (i) control rats, (ii) rats treated with 1,25(OH)2D3, (iii) rats treated with 24,25(OH)2D3, and (iv) rats treated with 1,25(OH)2D3 and 24,25(OH)2D3. After 4 days, serum calcium in the 1,25(OH)2D3-treated group was 7.13 +/- 0.32 meq/liter (P less than 0.001 vs control). With the combination of 1,25(OH)2D3 and 24,25(OH)2D3 serum calcium was higher than that in control, 6.25 +/- 0.5 meq/liter (P less than 0.001 vs control), but lower than that in rats receiving 1,25(OH)2D3 alone (P less than 0.05). No change in serum calcium was seen in animals treated with 24,25(OH)2D3 alone. On the eighth day serum calcium in the 1,25(OH)2D3-treated group, 6.52 +/- 0.25, was higher than in the 1,25(OH)2D3 + 24,25(OH)2D3 group, 5.87 +/- 0.17 meq/liter, P less than 0.05, P less than 0.001 vs control. In both 1,25(OH)2D3- and 1,25(OH)2D3 + 24,25(OH)2D3-treated rats, hypercalciuria of similar magnitude occurred on the fourth and eighth day of treatment. No change in urinary calcium was seen in the control and 24,25(OH)2D3-treated rats. Thus, in 5/6 nephrectomized rats combined administration of 1,25(OH)2D3 and 24,25(OH)2D3 attenuates the calcemic response to 1,25(OH)2D3 without changes in urinary calcium excretion. These observations suggest that the effect of 24,25(OH)2D3 on serum calcium is different in 5/6 nephrectomized rats as compared to normal rats, in which an augmentation of serum calcium was observed following administration of both vitamin D metabolites. The effect of 24,25(OH)2D3 on serum calcium in rats with reduced renal mass may result from a direct effect of 24,25(OH)2D3 on the bone.

24,25-Dihydroxyvitamin D 3