Histomorphic analysis of the development of the pars interarticularis and its association with isthmic spondylolysis.

Study Design: Descriptive study analyzing the histologic development of human fetal lumbar spine pars interarticularis.

Objectives: To delineate the histologic development of the fetal pars interarticularis and correlate the development of the pars with isthmic spondylolysis.

Summary Of Background Data: Isthmic spondylolysis is present in 5% to 6% of the population.

An in oculo model for quantitation of vascular growth in the rat heart.

Study Objective: The aim was to describe, both qualitatively and quantitatively, vascularisation in an in oculo model that may prove useful for studying neovascularisation in the myocardium.

Design: Whole hearts from 13-14 d rat fetuses were implanted into the anterior chamber of host Sprague Dawley rats. Implant growth was monitored and at 3 months postimplantation grafts were recovered.

Remodeling of myocyte dimensions in hypertrophic and atrophic rat hearts.

Changes in hemodynamic load cause alterations in cardiac myocyte size, with regional variations in myocyte size distribution possible within the ventricular wall. We studied regional changes in cellular dimensions and their distribution in two models of cardiac hypertrophy and in cardiac atrophy in the rat. Combined volume-pressure overload was produced by 3,3',5-triiodo-L-thyronine (T3) treatment; atrophy was produced by heterotopic isotransplantation.