Human colorectal cancer cells not only express the nuclear vitamin D receptor (VDR) but are also endowed with 25-hydroxy-vitamin D(3)-1alpha-hydroxylase activity and therefore are able to produce the specific ligand for the VDR, the hormonally active steroid 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)). In the present study we show by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) as well as by Western blotting and immunohistochemical methods, that in human large intestinal carcinomas expression of the genes encoding the 25-(OH)D(3)-1alpha-hydroxylase as well as the VDR increases in parallel with ongoing dedifferentiation in the early phase of cancerogenesis, whereas in poorly differentiated late stage carcinomas only low levels of the respective mRNAs can be detected. This indicates that, through up-regulation of this intrinsic 1alpha,25(OH)(2)D(3)/VDR system which mediates the anti-mitotic effects of the steroid hormone, colorectal cancer cells are apparently able to increase their potential for an autocrine counter-regulatory response to neoplastic cell growth, particularly in the early stages of malignancy.

Adenocarcinoma↗

PubMedDate not supplied

Percutaneous penetration/dermal absorption of hair dyes in vitro.

This paper presents an in vitro technique to analyse percutaneous penetration and dermal absorption of hair dyes, topically applied to excised pig skin. Representative examples are given by the radio-labelled hair dyes p-phenylenediamine and bis-(5-amino-1-hydroxyphenyl)-methane. Both compounds were assessed under simulated use conditions and were analysed in representative formulations including the specific conditions for oxidation hair dyes. To be able to differentiate between topically adsorbed and systemically available amounts, the bioavailability of the hair dyes is defined as the amount penetrated and/or remaining in the exposed skin after removing the stratum corneum. Less than 1% of the assessed topically applied dyes was found to be bioavailable in the presence of hydrogen peroxide, typically added to oxidation hair dyes prior to applications. Compared with published results and unpublished in-house in vivo data, the level of confidence was high. Owing to in-house experience over about 5 years in using excised pig skin for measurements of percutaneous penetration and dermal absorption of hair dyes, the technique was found to be successful and appropriate to reduce the number of test animals normally used for toxicological assessments. The essentials of this technique are actually recommended by the SCCNFP (The Scientific Committee on Cosmetic Products and Non Food Products intended for Consumers) for the safety evaluation of cosmetic ingredients, particularly for hair dyes. The corresponding OECD guideline as well as the guidance document has been drafted and is currently in discussion on the level of the national coordinators.

Administration, Cutaneous↗

PubMedDate not supplied

[Roentgen criteria and radiologic results of the Hofer-Imhof (H-I) threaded acetabulum cup in first time implantation].

The Hofer-Imhof cup consists of a parabola-shaped titanium acetabular component with flat threads. These flat threads are designed to be self-cutting and allow accurate insertion without incarceration, even in sclerotic bone. In a prospective study conducted from May 1988 to July 1989, 143 Hofer-Imhof cups were implanted. Radiographic assessment included initial bone contact, cup position, fixation on osteophytes, presence of any radiolucencies or sclerosis, cup migration and bone ingrowth. Initial prosthesis fit was evaluated with a 20 degrees caudally angled anteroposterior X-ray for accurate demonstration of the threads. 119 of the Hofer-Imhof cups (83.2%) were available for radiographic follow-up at a mean of 65 months (min. 37 mo., max. 95 mo.). One cup required revision after 23 months due to infection. The cups had an average inclination of 47 degrees, and complete bone contact was evident in 86.6% on the postoperative X-ray. In 8.4% of the cups, some threads were not in contact with bone at the edge of the acetabulum. At final follow-up, 82.4% had complete bone ingrowth without any evidence of radiolucency (type I), 15.1% had near-complete bone ingrowth with minimal radiolucencies (type II), and 2.5% had predominantly fibrous fixation (type III). One cup (0.8%) showed excessive migration. The technique of anchorage using a flat thread, minimal bone resection as a result of the parabolic shape and the sandblasted titanium surface are the characteristic features of the Hofer-Imhof threaded cup and produce good medium-term results in primary hip arthroplasty.

Acetabulum↗