Cytotoxicity tests for antimicrobial agents using cultured skin substitutes fixed at interface of air and culture medium.

The present study is focused on a new cytotoxicity test using cultured dermal and epidermal sheets, which are fixed at the air and medium interface as a wound surface model. The cultured dermal sheet is composed of human fibroblasts and a collagen matrix, and the cultured epidermal sheet is composed of human keratinocytes and a collagen matrix. Each cultured sheet was fixed at the air and medium interface, over which a piece of test specimen was placed. The in vitro system created, provides a mimetic wound surface since during wound repair, fibroblasts are embedded in an extracellular matrix, while keratinocytes migrate and proliferate on provisional granulation tissue. The results thus obtained in this cytotoxicity test are useful for determining the efficacious amount of antimicrobial agent used in clinical cases.

A cultured skin substitute composed of fibroblasts and keratinocytes with a collagen matrix: preliminary results of clinical trials.

The cultured skin substitute was created through successive cultivation of fibroblasts and keratinocytes that were combined within a collagen matrix. This collagen matrix was composed of a collagen spongy sheet and a collagen gel. The collagen spongy sheet was designed to produce a honeycomb structure having many holes in which all holes through the sheet were filled with collagen gel. This specific structure thereby allows for the nourishment of the cultured keratinocytes on the surface of the matrix when placed on the graft bed. In this study, autologous cultured skin substitute was applied to a 51-year-old man who had sustained a burn injury. Three sheets of the cultured skin substitute (6 x 9.5 cm) were grafted onto the full-thickness excised wound in the right anterior chest wall. One week after grafting most of the matrix disappeared and stratified keratinocytes were seen to have firmly attached to the underlying tissue. Five weeks after grafting a cornified epidermal layer was seen. Ten months after grafting a mature epidermis and a well-differentiated papillary and reticular dermis replacement were observed. The physical properties and color of this grafted area resemble those of normal skin. In the second test case, autologous cultured skin substitute was applied to a 30-year-old man with a scar remaining after tattoo removal. Eight sheets of the cultured skin substitute (10 x 18 cm) were applied on an excised wound (thickness, 0.02-0.025 in.) of both the fore- and upper arms. The histological appearance of a biopsied skin specimen from the grafted area at 3 months after grafting showed a mature epidermis and a well-differentiated reticular dermis replacement. The regenerated skin at 14 months after grafting showed an excellent result.

[Significance of prostatic specific antigen in the mass screening for prostate cancer].

The significance of prostatic specific antigen (PSA) was investigated in the subjects examined by the mass screening for prostate cancer from 1985 to 1990. All subjects was examined by digital rectal examination (DRE) and with prostatic acid phosphatase (PAP) and the subjects in whom prostate cancer (Pca) was suspected from abnormal DRE and/or elevated PAP were recommended to receive the secondary screening to confirm the presence of Pca. PSA was measured by radioimmunoassay using Ball-Elsa-PSA-kit. 1,600 serum samples were obtained from our serum bank. The relationship among PSA, prostate size estimated by DRE and age was investigated. PSA was increased with age and the prostate size, PSA being more closely related with the latter. Therefore, we estimated that PSA has an ability to detect benign prostatic hypertrophy (BPH) in the mass screening. This estimation should be confirmed by using an ultrasound tomography because the prostate size obtained by DRE is inaccurate as compared with that obtained by ultrasound tomography. The cut off level of PSA was determined by control which was composed from the subjects with normal size prostate and one with BPH. When the cut off level was 8.6 ng/ml, the sensitivity, specificity and efficiency as Pca marker was 73.9%, 97.4% and 97.1%, respectively. PSA was more than 8.6 ng/ml in all of Pca with elevated PAP. PSA was expected to improve the Pca detection rate in our mass screening system.

[A giant bladder stone with a small urethral stone].

A 71-year-old man had pollakisuria, macrohematuria and sense of urinary retention. His urethrogram showed a giant bladder stone with a small urethral stone. He received cystolithotomy. The giant bladder stone was removed. It weighed 310 g and is the 32nd reported in Japan.