Repression of the embryonic myosin heavy chain phenotype in regenerating chicken slow muscle is dependent on innervation.

Ventricular-like and fast myosin heavy chains (VL-MHC and FMHC) are transiently expressed during slow skeletal muscle development. The influence of innervation on repression of these MHC isoforms is investigated over an 84-day time course in: (1) normal anterior latissimus dorsi (N-ALD) muscles, (2) regenerating ALD (R-ALD) muscles, (3) denervated ALD (D-ALD) muscles, and (4) regenerating and denervated ALD (RD-ALD) muscles. Western blotting demonstrates that the VL-MHC is expressed in R-, D-, and RD-ALD muscles, but not in N-ALD muscles. Expression of the VL-MHC is transient in R-ALD muscles. In contrast, VL-MHC expression persists in RD-ALD muscles, and appears with time in D-ALD muscles. FMHC was not detected in N-ALD muscles by Western blotting. Two FMHCs are seen in R-ALD and RD-ALD muscles, and in 13-day embryonic ALD muscles. The slower migrating FMHC (FMHCA) comigrates with developmentally regulated FMHCs in fast pectoralis muscle, while the faster migrating FMHC (FMHCB) comigrates with the faster migrating FMHC in embryonic ALD muscle (13 days in ovo). FMHCB decreases in amount over the time course in R-ALD muscles, while FMHCA persists. In contrast, substantial levels of both FMHCs persist in RD-ALD muscles, and appear with time in D-ALD muscles. The cellular distribution of MHCs is followed by immunocytochemistry. Regenerating cells expressing VL-MHC and FMHC are replaced by a mature population in R-ALD muscles. Some of the mature myofibers in R-ALD muscles express FMHC, but not VL-MHC. In RD-ALD and D-ALD muscles, both regenerating and mature muscle cells are seen which express VL-MHC and FMHC. Our results indicate that innervation is required for the repression of VL-MHC and FMHCB during regeneration of slow muscle.     

Primary carcinoid tumor of the urinary bladder.

A 62-year-old woman who presented with urinary frequency and microscopic hematuria was found to have a 1.2 x 1.0 x 0.6-cm polypoid carcinoid tumor of the urinary bladder. The tissue resected from the base after removal of the polypoid lesion disclosed a small focus of residual carcinoid tumor, associated with Brunn's epithelial nests, cystitis cystica, and cystitis glandularis. Tumor cells exhibited strong argyrophilia and weak argentaffinity. Immunohistochemical staining reactions were strongly positive for chromogranin and serotonin, and electron microscopy revealed characteristic dense-core granules. Flow cytometric evaluation revealed an aneuploid cell population with a DNA index of 1.20.     

The internal mammary artery binds more 125I-albumin than the aorta]

The internal mammary artery is currently the arterial replacement of choice for coronary artery bypass grafts. The authors studied the permeability of the vessel wall of the internal mammary artery and the ascending aorta in 12 patients undergoing coronary artery bypass grafts by comparing the 125I-albumin binding profiles. Their results suggest that albumin crosses the internal mammary artery more easily than in the aorta.     

What Are American Children Eating? Implications for Public Policy

As the health and demographic profile of the U.S. population changes, the food consumption patterns of American children have also changed. This review is organized around a series of policy issues looking at these new food consumption patterns, their relationship to the Dietary Guidelines, and their impact on children's health.