Calbindin D28K regulation in precociously matured chick egg shell gland in vitro

Egg shell calcification in the hen uterus (egg shell gland, ESG) depends primarily on intestinal absorption of dietary Ca2+ as well as ESG Ca2+ transport into the shell. Intestinal Ca2+ absorption is linked to vitamin D-induced calbindin D28K (D28K) concentration. The ESG also contains D28K, and Ca2+ transport into the shell appears to be linked to D28K gene expression, but until this report, there was no direct proof that ESG D28K was or was not vitamin D-dependent. To address this issue, highly developed ESG from estradiol (E2)-injected, severely vitamin D-depleted chicks were cultured in serum-free medium with excellent viability. Addition of the vitamin D-hormone, 1,25(OH)2 vitamin D3 (1,25), to the culture medium increased ESG D28K levels as much as 70%. E2 alone had no effect, but E2 plus 1,25 further increased ESG D28K levels up to 160%. By contrast, progesterone (P4) prevented the 1,25-stimulated increase in D28K, while having no effect on basal D28K level. Of considerable interest, thapsigargin (THAPS), which increases intracellular Ca2+ concentration ([Ca2+]i) in many cell types, stimulated D28K synthesis in a concentration-dependent manner in the complete absence of 1,25 and independent of the [Ca2+] of the medium. These results are the first direct evidence that ESG D28K is under direct control of 1,25 and that both gonadal steroid hormones, E2 and P4, may be coregulators. Further, the effects of THAPS suggest that [Ca2+]i itself may also regulate D28K. This new in vitro model clearly represents a unique opportunity to study the regulation of the ESG calcium transport mechanism under stringently defined conditions.     

Bulbous splenic vein as a cause of renal pseudotumor

A number renal and suprarenal pseudotumors have been described during the past two decades, paralleling the development of selective visceral angiography. An apparent left upper pole renal mass in a 71-year-old hypertensive man was found to ba a bulbous portion of the splenic vein during angiography. The anatomical basis of this renal pseudotumor is discussed.     

An assessment of concurrent Pascal

This paper assesses Concurrent Pascal against its design aims. The language is shown to be suitable for writing reliable non-trivial concurrent applications programs and operating systems. The major weakness of the language is its inability to provide an environment for other Concurrent Pascal programs. A new language construct, group, is proposed to remedy this difficulty.