[Periprosthetic femoral bone reaction after total hip arthroplasty with preservation of the collum femoris : CT-assisted osteodensitometry 1 and 3 years postoperatively]

BACKGROUND

Short-stemmed cementless femoral components in total hip arthroplasty have been designed to preserve the proximal femoral bone stock by load transfer to the femoral metaphysis. An in vivo method of computed tomography-assisted (CT) osteodensitometry after total hip arthroplasty is presented which differentiates between cortical and cancellous bone density (BD) changes around uncemented femoral components.

PATIENTS AND METHODS

Cortical and cancellous periprosthetic femoral BD (mg Ca HA/ml) was determined prospectively in 31 patients at day 10, 1 year and 3 years after total hip arthroplasty with preservation of the collum femoris (C.F.P.-stem, Link, Hamburg, Germany) using computed tomography-assisted osteodensitometry. Clinical results (Harris hip score) and plain x-rays were assessed in all cases.

RESULTS

Progressive proximal cortical BD loss was observed between the 1 year (Ø -8%) and 3 year (Ø -22%) postoperative measurements. Distal to the trochanter minor no significant cortical BD changes were observed. Proximal cancellous BD decreased progressively between the 1 year (Ø -33%) and 3 year (Ø -45%) analyses. The Harris hip score improved from 45 points pre-operatively to 93 points at the 3 year follow-up. All x-rays showed signs of stable ingrowth.

CONCLUSION

Periprosthetic CT osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Progressive proximal cortical and cancellous BD loss indicates that metaphyseal fixation cannot be achieved with the analyzed C.F.P. stem design. The lack of cortical BD loss below the trochanter minor suggests diaphyseal fixation of the implanted stem.

Estrogen receptors alpha and beta and progesterone receptors in normal bovine ovarian follicles and cystic ovarian disease

The purpose of this study was to determine by immunohistochemistry the expression of estrogen and progesterone receptors in ovarian follicular structures from cows with cystic ovarian disease (COD) and to compare these with normal ovarian structures. Secondary, tertiary, atretic, and cystic follicles were evaluated. The follicular cysts of animals with COD presented a significantly higher expression of estrogen receptor alpha in all follicular layers than secondary, tertiary, and atretic follicles in both groups (P < .05). The intensity of estrogen receptor beta in the granulosa cell layer was stronger in tertiary than in secondary and atretic follicles in normal animals (P < .05) and in growing and cystic follicles in animals with COD (P < .05). Theca cells were scarcely stained in the 2 groups. Growing follicles and cysts from COD animals were less stained than tertiary follicles from normal animals (P < .05). Differences did not exist between the 2 groups with regard to the progesterone receptor. Ovaries of animals with COD exhibited altered estrogen receptors expression compared with that in normal animals.

Analgesic activity of cyclic imides: 1,8-naphthalimide and 1,4,5,8-naphthalenediimide derivatives

In early studies, we have reported the synthesis and biological activities of several cyclic imides. The present study describes the analgesic activity of 1,8-naphthalimide and 1,4,5,8-naphthalenediimide derivatives in a standard murine model of analgesia. The pharmacological results show that all compounds studied, given intraperitoneally, produced significant inhibition of acetic acid-induced abdominal constrictions. At the ID50 (micromol/kg) level, these cyclic imide derivatives were about 40-270-fold more potent in this assay than aspirin and acetaminophen, two well-known and widely used analgesics. These results extend previous studies on the analgesic activity of cyclic imides.

Frozen shoulder: a sympathetic dystrophy?

Diagnostic and clinical features of the frozen shoulder syndrome and the Sudeck syndrome are similar in many aspects. Radioisotope bone scan shows an increased uptake in affected areas in both diseases, while native radiographs show a progressive demineralisation. Measurement of bone mineral density (BMD) by quantitative digital radiography objectified these local decalcification processes in an early stage of the frozen shoulder syndrome; 10 of 12 patients with primary frozen shoulder had BMD decreases greater 21% in the humeral head of the affected shoulder compared to the non-affected side. In the immobilised control group with degenerative changes of the rotator cuff, calcifying tendinitis and shoulder instability (n = 12) and in the group of healthy probands (n = 20), the difference between the affected and non-affected side (left and right humerus of the healthy probands) was only more than 21% in one case each. There are several references in the literature that assume frozen shoulder to be an algoneurodystrophic process; our observations support this hypothesis, possibly leading to earlier diagnoses and extended therapeutic management.

Effect of vector on infectivity of Trypanosoma cruzi

A comparative study was carried out on the interaction between Triatoma infestans and bloodstream forms (BSF) of Trypanosoma cruzi isolates RA and UP, both lethal for mouse, and CA-I nonlethal for this host. Parasite duplication was readily detected in triatomes fed with CA-I, metacyclic (Mtc) differentiation reaching a maximum at an optimum ingestion level of 250 BSF/insect. Progress and differentiation proved much lower for RA, but reached intermediate values for the UP isolate. Assays for infectivity for each isolate after bug passage revealed a drop for the RA and UP, whereas for CA-I an increase was observed indicating that virulence of BSF and Mtc differs. Our results suggest that parasite selection by insect passage modulates infectivity of a given parasite population; however, virulence was independent of the absolute number of Mtc in the insect's feces.