The impact of a worker health study on working conditions

A research partnership of representatives from labor, academia, and public health enabled unionized San Francisco hotel workers to achieve important policy changes in workplace health and safety. Known as the "Housekeeping Study," the project took sixteen months to complete. A unique aspect of the project was that it utilized participatory action research methods, involving workers themselves as full participants in the study. A core group of 25 hotel room cleaners was involved in each phase of the project. The study developed health data which enabled room cleaners and their union to formulate and justify a contract proposal calling for a significant reduction in housekeeping workloads. The employer association agreed to a contract which reduced the maximum required room assignment from 15 rooms to 14 rooms per day in 14 San Francisco hotels. By lowering the maximum work assignment, these workers set a new standard which can potentially protect the health of room cleaners across the country. The project can serve as a model for worker and union participation in academic research, as well as for the application of research to improving working conditions, particularly for low-wage immigrant workers.     

Monoclonal antibodies selective for low molecular weight neurofilaments

Neurofilaments are necessary for the maintenance of axonal caliber and structural organization of nerve cells. The low molecular weight form of neurofilament, the neurofilament light protein, which serves as the core of the filament, was used as immunogen for generation of hybridomas with selective reactivity with this form of the filament. Six hybridomas, out of approximately 100 tested clones, were highly discriminatory. All involved epitopes were localized to the rod region of the antigen, as determined by alpha-chymotrypsin digestion of the purified filament and enzymatic peptide mapping. Synthetic peptides (20 mers) covering the entire rod region did not react with the antibodies. A phage display peptide library was used to identify four consensus sequences for the antibodies. The results indicate that all epitopes were of conformational type. Pair-wise BIAcore data furthermore indicated that the epitopes were independent. The access to such specific reagents is a prerequisite for further elucidation of the biology of the low molecular weight form of neurofilaments proteins.     

Dynorphin-(1–13).

Dynorphin-(1–13) (Dyn-(1–13)) and its analogs substituted by single introduction of Ala in positions 1–11 were synthesized by the solid-phase method and purified by high pressure liquid chromatography. Relative potencies of the synthetic compounds were determined by their ability to inhibit electrically-evoked contractions of the guinea pig ileum (GPI) and of the mouse vas deferens (MVD) and to compete with [³H]-etorphine for opiate receptors in rat brain homogenates. Introduction of Ala in positions 1 and 4 of Dyn-(1–13) provoked most important decreases in the activity of the molecule in the three assays (relative potency of 0.2% or less). Substitution of Ala in positions 2 or 5, but not 3, also severely decreased the potency of the peptide in the smooth muscle preparations (0.6–5.0% activity). However, the opiate receptor binding assay was less sensitive to the replacement of residue in position 2 (20% activity) than that in positions 3 or 5 (12% and 6% relative potencies, respectively). In the GPI assay and the opiate binding test, the other substitutions which greatly lowered the potency of the molecule were seen in positions 6, 7, 9 and 11, four basic residues. Among these, Arg⁶ and Arg⁷ were demonstrated to be the most important in the three biological tests. Finally, the replacement of Ile⁸ by Ala increased the relative potency of Dyn-(1–13) up to 191% and 900% in the MVD and the opiate binding tests, respectively.     

Rapid detection of a mutation hot-spot in the human androgen receptor

Mutations of the human androgen receptor gene may disturb sexual development in males, and are inherited as an X-linked recessive trait. The vast majority of the mutations are familial. We have identified a large kindred with complete androgen insensitivity syndrome (CAIS) without detectable androgen-binding in genital skin fibroblasts. A single nucleotide substitution (C-to-T transition) was identified, resulting in an Arg⁸⁵⁵ to Cys in the androgen binding domain. To date, four independent CAIS families have been reported with this specific mutation that coincides with the propensity of cytosines at CpG dinucleotides to methylate. An allele-specific oligo-nucleotide assay was developed that allowed for the rapid and specific identification of this mutation hot-spot in individuals with androgen receptor incensitivity syndromes.     

Pitfalls in estimating piperaquine elimination

By using a sensitive new assay, the terminal elimination half-life of the antimalarial piperaquine in a healthy volunteer was estimated to be 33 days, which is longer than estimated previously. This result illustrates the importance of extended sampling duration and sensitive assay methodologies in characterizing the disposition of slowly eliminated antimalarial drugs.     

The antiarrhythmic peptide analog rotigaptide (ZP123) stimulates gap junction intercellular communication in human osteoblasts and prevents decrease in femoral trabecular bone strength in ovariectomized rats

Gap junctions play an important role in bone development and function, but the lack of pharmacological tools has hampered the gap junction research. The antiarrhythmic peptides stimulate gap junction communication between cardiomyocytes, but effects in noncardiac tissue are unknown. The purpose of this study was to examine whether antiarrhythmic peptides, which are small peptides increasing gap junctional conductivity, show specific binding to osteoblasts and investigate the effect of the stable analog rotigaptide (ZP123) on gap junctional intercellular communication in vitro and on bone mass and strength in vivo. Cell coupling and calcium signaling were assessed in vitro on human, primary, osteoblastic cells. In vivo effects of rotigaptide on bone strength and density were determined 4 wk after ovariectomy in rats treated with either vehicle, sc injection twice daily (300 nmol per kilogram body weight) or by continuous ip infusion (158 nmol per kilogram body weight per day). During metabolic stress, a high affinity-binding site (KD=0.1 nM) with low density (15 fmol/mg protein) for [125I]di-I-AAP10 was demonstrated. During physiological conditions, specific binding sites for [125I]AAP10 could not be shown. Studies of the effects of rotigaptide on propagation of intercellular calcium waves and cell-to-cell coupling demonstrated that 10 nM rotigaptide produced a small increase in intercellular communication during physiological conditions (+4.5+/-1.6% vs. vehicle; P<0.05). During conditions with metabolic stress, 10 nM rotigaptide produced an increase in coupling measured by both methods. Four weeks after ovariectomy, bone strength of the femoral head was reduced by 20% in vehicle-treated ovariectomized rats, which was completely prevented in both rotigaptide-treated groups. Rotigaptide also prevented decreases in bone mineral. We conclude that the stable analog rotigaptide increases gap junctional communication in osteoblasts in vitro and preferably during conditions with metabolic stress. Rotigaptide further prevents ovariectomy-induced bone loss in vivo. Thus, gap junction modulation may be a promising new target for osteoporosis therapy.     

Endogenous p63 acts as a survival factor for tumour cells of SCCHN origin

The human p63 gene encodes a series of proteins that differ in their N- and/or C-terminal sequences and have widely differing properties in promoting or repressing p53-related functions such as growth arrest and apoptosis. In addition, p63 has important roles in the maintenance and differentiation of epithelial cell populations. Squamous cell carcinomas of the head and neck (SCCHN) express high levels of DeltaNp63 and p63beta isoforms compared to normal tissue from the same patients, suggesting a role for these isoforms in the pathogenesis of this common human malignancy. Here, we explore the function of p63 in SCCHN cells by using small interfering RNA (siRNA) to silence the expression of different isoforms in two SCCHN cell lines, FaDu and SCC-25. Silencing results in statistically significant decreased survival for tumour cells when all p63 isoforms, the N-terminal truncated or the alpha isoforms are inhibited. No effect was observed on cell proliferation or on the expression of epithelial differentiation markers. We also demonstrate that inhibition of endogenous p63 expression sensitises cells to the effects of ionizing radiation and cisplatin, common treatments for SCCHN patients. The data indicate that p63 has oncogenic properties in SCCHN and is predominantly involved in maintaining cell survival, rather than acting as a directly proliferative factor or as an inhibitor of terminal differentiation. Moreover, targeted inhibition of p63 expression in SCCHN could be a useful adjunct for conventional treatments of this disease.