[Reliability of Amplicor Mycobacteria test for detection of Mycobacterium tuberculosis complex. M. avium and M. intracellulare: a cooperative study among 9 laboratories].

The Amplicor Mycobacteria, a PCR-based assay, is a rapid test for the detection of Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium intracellulare in clinical samples. To estimate the reliability and reproducibility of the method, a cooperative blind study was conducted among 9 laboratories. Materials used for testing consisted of 105 sputum and 30 water samples containing known numbers of M. bovis BCG, M. avium, M. intracellulare, and samples without bacteria. Only 2 out of the 9 laboratories correctly identified the presence or absence of mycobacterial DNA in all 135 samples. In sputum samples, 6 out of the 9 laboratories detected mycobacterial DNA in all positive samples, and 4 out of the 9 laboratories correctly reported the absence of DNA in the negative samples, indicating the need for good laboratory practice and development of reference reagents to monitor the performance of the whole study, including pretreatment of clinical samples. The main problem was lack of specificity rather than lack of sensitivity. From about half of the laboratories, false-positive results were reported, however, the ratio was below 6%; 1% (1/106 sputum samples) in 3 laboratories, 1.9% (2/105) in 2 laboratories, and 5.7% (6/105) in one laboratory, respectively. These results indicate that the Amplicor Mycobacteria is quite useful for a rapid diagnosis of tuberculosis.

Periosteal ganglion: a report of three new cases including MRI findings and a review of the literature.

OBJECTIVE: To clarify the clinicopathological features of periosteal ganglion. DESIGN: Three patients with periosteal ganglion were studied clinicopathologically. PATIENTS: One patient was selected from the files of our institute and two from a consultation file. RESULTS AND CONCLUSION: All three lesions were located over the medial aspect of the tibia. Plain radiographs showed cortical erosions of varying degrees and mild periosteal reaction of the medial side of the tibia. MR images demonstrated well-circumscribed lesions overlying the cortical bone of the tibia, shown as low-intensity areas on T1-weighted images. On T2-weighted images, lesions were homogeneous, lobulated, and showed a characteristic markedly increased signal intensity. These findings are helpful in making a diagnosis of periosteal ganglion. Each patient had an uneventful clinical course after an excision involving the wall of the ganglion, the adjoining periosteum, and the underlying sclerotic cortical bone.

[Effect of human PTH on steroid-induced osteopenia: a histomorphometric study of decalcified and undecalcified trabecular bone sections in rat].

Serum and urine chemical analyses were combined with a bone histomorphometrical study of rat metaphyses to evaluate the osteogenetic effect of intermittent administration of human parathyroid hormone (h-PTH) on steroid-induced osteopenia. Seven-month-old female Wistar rats were divided into the following 4 groups: (1) a control group: age-matched and untreated; (2) a baseline control group (BL group): given 2.5 mg/kg prednisolone subcutaneously 6 times/week for 8 weeks, at the end of which the animals were sacrificed; (3) a PTH group: in the 9th week of continuous steroid administration, 6.0 micrograms/kg h-PTH was added to the regimen; and the animals were sacrificed in the 12th week; (4) a vehicle group, as a control for the h-PTH group: only the vehicle was administered instead of PTH. At the necropsy at the end of the experiment, both tibias were collected. The undecalcified sections were stained by Villanueva bone stain and labelled with tetracycline, and the decalcified sections were stained by TRAP, and examined histomorphometrically. Serum Ca and P were not changed by any treatment. Serum 1,25 (OH)2D3 values were significantly increased in rats treated with h-PTH. There was no significant change in urinary Ca, P, or hydroxyproline excretion in any group. Histomorphometrically, the parameters related to bone formation--osteoid surface, mineralized surface and bone formation rate--were all reduced in the BL group and in the vehicle group. The bone volume was significantly lower in these group than in controls. The PTH group, on the other hand, showed increases in the osteoid surface, mineral apposition rate, and bone formation rate and the bone volume was significantly higher than in controls. The PTH group showed no increases in the osteoclast number or in the osteoclast surface. These results suggested that intermittent administration of h-PTH activated bone formation only, and increased bone volume.