Medicine and Health Sciences Commons^™

Lumbar Vertebral Density And Mechanical Properties In Aged Ovariectomized Rats Treated With Estrogen And Norethindrone Or Norgestimate, Carla Vanin, Neil Maclusky, Debbie Chachra, Mehran Kasra, Marc Grynpas, Robert Casper

Debbie Chachra

OBJECTIVE: This study was designed to investigate the effects of estrogen alone or combined with two different progestins, norethindrone or norgestimate, on bone density and compressive mechanical properties in an aged rat model.

STUDY DESIGN: Twenty 11-month-old female Sprague-Dawley rats were sham operated (intact control) and 80 wee overiectomized. Three groups of 20 ovariectomized rats were implanted with Silastic silicon rubber (Dow Corning, Midland, Mich.) capsules containing 5% estradiol (wt/wt) in cholesterol. All rats in the intact control (group 1) and the ovariectomized (group 2) and the first of the overiectomized plus estrogen (group 3) groups were injected subcutaneously daily …

The Effect Of Different Hormone Replacement Therapy Regimens On The Mechanical Properties Of Rat Vertebrae, Debbie Chachra, M. Kasra, Carla Vanin, N. Maclusky, R. Casper, Marc Grynpas

Debbie Chachra

The purpose of this study was to examine the effects of estrogen replacement, in concert with three different progestin regimens, on the mechanical properties of rat lumbar vertebrae. Ninety-two Sprague-Dawley rats (11 months old) were divided into six groups for treatment. The first group was an intact control, the second group (OVX) was ovariectomized only, and the third group (estrogen-only) was ovariectomized and received continuous estrogen through a 17-estradiol implant. The remaining groups were ovariectomized and received estrogen and progestin (norethindrone, NET) therapy; 3 g of NET was injected daily (estrogen plus continuous NET), or 6 g of NET was …

The Long-Term Effects Of Water Fluoridation On The Human Skeleton, Debbie Chachra, H. Limeback, T. Willett, Marc Grynpas

Debbie Chachra

Municipal water fluoridation has notably reduced the incidence of dental caries and is widely considered a public health success. However, ingested fluoride is sequestered into bone, as well as teeth, and data on the long-term effect of exposure to these very low doses of fluoride remain inconclusive. Epidemiological studies suggest that effects of fluoride on bone are minimal. We hypothesized that the direct measurement of bone tissue from individuals residing in municipalities with and without fluoridated water would reveal a relationship between fluoride content and structural or mechanical properties of bone. However, consonant with the epidemiological data, only a weak …

Tensional Forces Influence Gene Expression And Sutural State Of Rat Calvariae In Vitro, S. Tholpady, T. Freyman, Debbie Chachra, R. Ogle

Debbie Chachra

BACKGROUND:

Theories regarding the cause of craniosynostosis that are more than 15 years old cite the role that tensional forces play in the normal and abnormal development of the cranial suture. These theories highlight the effect of stress bands originating from the skull base to the vertex, guiding sutural development.

METHODS:

In this study, the normally fusing posterior intrafrontal suture of the rat was subjected to 3 mN of tensional force for 30 minutes per day. The suture was then assessed for patency, proliferation, apoptosis, and transforming growth factor (TGF)-beta signaling components.

RESULTS:

Sutures that were subjected to tensional force …