Alendronate preserves femoral head shape and height/length ratios in an experimental rat model: A computer-assisted analysis.

Background: Surgical osteonecrosis of the rat femoral head was induced by detaching the ligamentum teres and stripping the femoral neck periosteum. Bone and marrow necrosis were found from the fifth postoperative day and replaced by creeping substitution. Osteonecrosis of the femoral head results in the flattening to various degrees of roundness and osteoarthritic changes of the hip joint.

Prevention of distortion of vascular deprivation-induced osteonecrosis of the rat femoral head by treatment with alendronate.

Introduction: In animals with a disrupted blood supply and drainage of the femoral head, the dead epiphyseal bone undergoes osteoclastic osteolysis and is replaced by newly synthesized, immature, and weak bone, which cannot withstand the daily loads and, therefore, the articular surface caves in.

Methods: Female Sprague-Dawley rats with interrupted blood circulation of the femoral head were treated with alendronate and compared to controls.

Results: There was no distortion of the femoral heads in the alendronate-treated animals.

Vasculature deprivation-induced osteonecrosis of rats' femoral heads associated with the formation of deep surface depressions.

Background: Shallow or deep bowl-shaped depressions often develop after drilling an intraosseous conduit in the necrotic, avascular femoral head of rats. The etiopathogenesis of tissue loss at the articulation surface after a drilling procedure was elaborated in the authors' previous reports.

Goals: To scrutinize a large collection of femoral heads of rats in order to search for similar changes in cases in which no drilling procedure was carried out.

Vasculature deprivation--induced osteonecrosis of the rat femoral head as a model for therapeutic trials.

EXPERIMENTAL OSTEONECROSIS: The authors' experience with experimentally produced femoral capital osteonecrosis in rats is reviewed: incising the periosteum at the base of the neck of the femur and cutting the ligamentum teres leads to coagulation necrosis of the epiphysis. The necrotic debris is substituted by fibrous tissue concomitantly with resorption of the dead soft and hard tissues by macrophages and osteoclasts, respectively. Progressively, the formerly necrotic epiphysis is repopulated by hematopoietic-fatty tissue, and replaced by architecturally abnormal and biomechanically weak bone.

Intramyofiber erythrocytes in skeletal muscle.

The authors describe the serendipitous discovery of clustered erythrocytes within myocytes in a biopsy obtained during repair of a torn tendon. Their perusal of the literature failed to uncover an analogous observation.

Pyogenic granuloma-like reaction in the necrotic, vessels-deprived femoral head of the rat.

Osteonecrosis of the femoral head was produced in rats by cutting the ligamentum teres and incising the cervical periosteum. As of the second postoperative week, fibrous tissue pervaded the necrotic epiphyses, macrophages and osteoclasts removed the debris, osteoblasts deposited lamellar-fibred and woven-fibred intramembranous bone, and remodeling began. In 16% of the rats killed during the 2nd postoperative week, the epiphyses contained big fragments of necrotic bone enclosed by densely packed, capillary-sized vessels.

Liesegang rings in hemorrhagic urine.

Myriad Liesegang rings were encountered in the urine of a 43-year-old patient who was diagnosed as having idiopathic hematuria, emanating from the left ureter or kidney. Erythrocytes and the Liesegang rings spontaneously disappeared from the urine within 4 weeks. We are unaware of a report of a similar observation.

Fractal dynamics in the differential diagnosis of thyroideal follicular neoplasms.

In this study, we investigated the sensitivity, specificity, and predictive values of morphometric parameters of thyroideal follicular neoplasms based on concepts of fractal geometry. Thirty-seven follicular adenomas and 36 well-differentiated follicular carcinomas were assessed morphometrically. The nuclear area, nuclear area fraction, nuclear regularity factor, nuclear elongation factor, and slope setting (representing the ratio between the nuclear perimeter and nuclear regularity factor) were subjected to fractal dimensions analysis.

The prognostic significance of the semiquantitatively determined estrogen receptor content of breast carcinomas. A clinicopathological study.

Response of breast carcinomas to tamoxifen treatment depends, among others, on the estrogen receptor status. The estrogen receptor content was semiquantitatively determined in immunostained sections of stage 1 and 2 cancers of patients who had undergone tumor excision, tamoxifen treatment, adjuvant chemotherapy and radiotherapy. Weighted scores of the estrogen receptor content of the tumors were established by calculating the arithmetic means of the intensity of stained nuclei and the number of positively stained nuclei.

The effects of enoxaparin on the reparative processes in experimental osteonecrosis of the femoral head of the rat.

The blood supply of one femoral head of 6-month-old rats was severed by incising the periosteum of the neck and cutting the ligamentum teres. The rats were killed on the 30th postoperative day and the femoral bones were obtained for semiquantification of the reparative processes in the necrotic heads. Fourteen rats were treated with enoxaparin and 14 untreated animals served as controls.