Background. The bcl‐2 protein has been shown to suppress apoptosis, and overexpression of the bcl‐2 protein has been reported in several malignant tumors. Skin is one of the largest organs in the body, and the most common human malignancies arise from keratinocytes in the epidermis. In this paper, the authors analyzed immunohistochemically the expression of the bcl‐2 protein in several keratinocytic (KC) tumors and inflammatory skin disorders to investigate the role of bcl‐2 in the development of benign and malignant skin tumors. Methods. Seventy‐two frozen tissues from patients with inflammatory KC proliferation (chronic dermatitis [CD] and psoriasis vulgaris [PV]), seborrheic keratosis (SK), carcinoma in situ of KC tumors (actinic keratosis [AK] and Bowen's disease [BD]), basal cell carcinoma (BCC), and squamous cell carcinoma (SCC), 2 SCC cell lines, and 20 normal skin were immunostained with an anti‐bcl‐2 monoclonal antibody. Results. Tissue with normal KC, CD, PV, and SK scarcely expressed the bcl‐2 protein. Seventy‐three percent of tissue with BD, 25% with AK, 67% with BCC, and 100% with SCC showed obvious bcl‐2 protein expression. bcl‐2 expression of BCC, BD, and SCC was restricted to the involved lesions, and surrounding normal tissue with KCs were bcl‐2 negative. Interestingly, tissue with atrophic AK expressed no bcl‐2 protein (none of five cases), whereas tissue with hypertrophic AK reacted weakly with the anti‐bcl‐2 antibody (two of three cases). Conclusions. bcl‐2 protein expression in patients with KC may be related to tumorigenic proliferation possibly due to enhanced cell survival, but not when inflammatory proliferation of keratinocytes is present.

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Two types of hydroxyapatite (HA) implants have been developed: an HA-coated implant and a dense HA implant. For a longer in situ life span, the HA implant must remain chemically stable and possess high resistance to occlusal force. To determine which type of HA implant shows better durability, this comparative dog study was done to evaluate push-out test results of HA-coated implants and dense HA implants of approximately the same size after implantation in the mandibular and coxal bones for periods ranging from 3 weeks to 10 months. The findings revealed that for the mandibular implants, the push-out values of HA-coated implants were significantly higher than those of dense HA implants at 2 and 4 months after implantation, with significance levels of p < .001 and p < 0.05, respectively. However, there was no significant difference between the two implant types at 10 months. As for the coxal implants, no significant differences were noted for any period. Furthermore, the ratio of push-out values of the dense HA implants to those of the HA-coated implants situated in the same position bilaterally in each bone of the body for each implantation period rose with the passage of time, especially in the mandible. In the mandibular implants, the correlation coefficient of the relationship between the ratio and duration of implantation was highly significant (p < 0.001). Push-out testing caused detachment of the surface portion of the HA coating that was bound to the dense bone from the HA-coated implant at 2, 4, and 10 months after implantation. Furthermore, at 10 months the HA-coated layer in the wide areas of the implants had completely detached from the metal substrate, in contrast to the dense HA implants, which remained durable throughout the test period.

We analyzed renal biopsy specimens from 100 patients to evaluate the characteristics of renal involvement in patients with rheumatoid arthritis (RA). Membranous nephropathy (MN) was the most common renal histological pattern (31%). Mesangial proliferative glomerulonephritis (GN) was found in 21% of cases (IgA nephropathy 12%, non-IgA GN 9%), minor changes in 17%, renal amyloidosis in 11%, interstitial nephritis in 9%, sclerotic GN in 4%, and crescentic GN in 2%. MN was relatively more frequent in men than in women, and most developed nephrotic syndrome, while a few developed renal failure. Diseasemodifying antirheumatic drugs (DMARDs) correlated with MN in 26 of 31 cases. Mesangial proliferative GN showed high-grade hematuria. Amyloidosis correlated with long duration of RA; approximately half of the cases with amyloidosis also had nephrotic syndrome, and 82% developed renal failure. Of the 100 patients, 82% showed some tubulointerstitial changes, which might be related to non-steroidal anti-inflammatory drugs. Because renal lesions in RA are very diverse, and early stage cases of MN and amyloidosis can be detected only by histological examinations, renal biopsy should be performed in cases with continuous urinary abnormalities or progressive renal failure.