A new HPLC fluorimetric method to monitor urinary delta-aminolevulinic acid (ALA-U) levels in workers exposed to lead

Summary A new sensitive HPLC method for the determination of urinary delta-aminolevulinic acid (ALA-U) was used to evaluate the relationship between blood-lead (Pb-B) and ALA-U levels in male workers exposed to lead. The differences between the ALA-U levels determined by this method (ALAU-HP) and by a colorimetric method (ALA-U-CL) are discussed. The HPLC method gave values similar to the ALA-U-CL values at high ALA-U level. However, at low blood-lead levels (58 ± 22 g/l, n = 23), the mean ALA-U-HP level corrected by urinary creatinine level was one-third of the corrected ALA-UCL level (0.83 ± 0.14 and 2.4 ± 0.5 mg/g creatinine, respectively). A significant increase of the mean corrected ALA-U-HP level was observed at 162 ± 22 g/l Pb-B (P < 0.05, n = 26), while that of ALA-UCL was observed at 245 ± 30 g/l Pb-B (P < 0.01, n = 37). The regression equation based on the logistic model fitted well to the relationship data between the Pb-B level and the percentage of the subjects with corrected ALA-U-HP above the cut-off point (1.12 mg/g creatinine) and the expected Pb-B level for 50% response was 270 g/l Pb-B, while it did not fit well to the relationship data between Pb-B level and the percentage of the subjects with corrected ALAU-CL above the cut-off point (3.5 mg/g creatinine). The maximum responses for the two sets of corrected ALA-U levels were both observed at 625 ± 25 g/l. The corrected ALA-U level by HPLC method seems to be a useful indicator for biological monitoring of exposure to lead at low levels (< 400 g/l Pb-B = health-based biological limit, WHO) as well as high ones.     

Polyclonal anti-desmosine antiserum is specific to desmosine molecule: no cross-reaction to pyridinoline

Inhibition ELISA assay was used to examine the cross-reaction of the polyclonal anti-desmosine antiserum produced in rabbit against molecules possessing a "pyridinium ring" as their core structure i.e. isodesmosine, pentasine, pyridinoline and 2'-deoxypyridinoline, highly purified with column chromatography, and structurally unrelated substances, i.e. cysteic acid, taurine and 2-aminopyridine (core structure of desmosine). No cross-reaction was observed to the pyridinoline, 2'-deoxypyridinoline possessing "pyridinium ring" and derived from collagen cross-links, structurally unrelated cysteic acid and taurine, nor core structure of 2-aminopyridine. The antiserum specifically recognized the molecules derived from the elastin cross-links. Using the ELISA assay system with antisera and amino acids analysis, 10 micrograms of desmosine were extracted from 1.0 mg of the hydrolysate of commercial elastin.     

Involvement of MMP-7 in invasion of pancreatic cancer cells through activation of the EGFR mediated MEK-ERK signal transduction pathway

AIMS: To clarify the involvement of matrix metalloproteinase-7 (MMP-7) in cell dissociation and the subsequent invasion of pancreatic cancer cells.METHODS: Western blotting, in vitro invasion assay, immunocytochemistry, and immunohistochemistry were performed in pancreatic cancer cell lines or pancreatic cancer tissue.RESULTS: The active form of the MMP-7 protein was expressed exclusively in the conditioned medium of dissociated (PC-1.0 and AsPC-1) pancreatic cancer cells, whereas proMMP-7 protein was only detected in the conditioned medium of non-dissociated (PC-1 and Capan-2) cells. Both intracellular and conditioned medium localised MMP-7 was greatly reduced by treatment with the epidermal growth factor receptor (EGFR) inhibitor AG1478 and the mitogen activated protein kinase kinase (MEK) inhibitor U0126 in pancreatic cancer cells. MMP-7 treatment significantly induced the disruption of tight junction (TJ) structures and subsequent cell dissociation, and activation of the EGFR mediated MEK- ERK (extracellular signal regulated protein kinase) signalling pathway in the non-dissociated pancreatic cancer cells. Moreover, the strong in vitro invasiveness of dissociated cells was inhibited by AG1478 and U0126 treatment, whereas the weak invasiveness of non-dissociated cells was apparently induced by MMP-7 treatment. In addition, MMP-7 expression was stronger at the invasive front than at the centre of human pancreatic tumours.CONCLUSION: MMP-7 is involved in cell dissociation and the subsequent invasion of pancreatic cancer cells. It induces the disruption of TJ structures and forms a positive feedback loop with activation of the EGFR mediated MEK-ERK signalling pathway.     

Diazepam reduces both arterial blood pressure and muscle sympathetic nerve activity in human

It is known that benzodiazepines have a hypotensive effect, but the mechanism has not been well elucidated yet. To clarify whether this effect is due to central or peripheral mechanism, we administered 5 mg of diazepam or saline intravenously to healthy volunteers and assessed the change in blood pressure, heart rate, muscle sympathetic nerve activity and heart rate variability. After diazepam administration, systolic and mean blood pressure decreased significantly. Muscle sympathetic nerve activity was also significantly reduced but heart rate did not change, whereas the variables of spectral analysis of heart rate variability did not show significant change. We concluded that the hypotensive effect of diazepam in human is mainly due to the central mechanism.     

Association of common missense changes in ELAC2 (HPC2) with prostate cancer in a Japanese case–control series

 The recently identified prostate cancer susceptibility gene ELAC2 (HPC2) harbors two common missense variants, a serine to leucine substitution at residue 217 (Leu217) and an alanine to threonine substitution at residue 541 (Thr541). We genotyped the two variants in a Japanese cohort consisting of 350 prostate cancer patients 242 male population controls, and 114 male low-risk controls. Both missense alleles, Leu217 and Thr541, were carried at higher frequency in Japanese patients than in the controls (Leu217, P = 0.0012; Thr541, P = 0.0145), and the odds ratios associated with carrying these sequence variants were higher in Japanese than in Caucasians. Although the Leu217 and Thr541 variants of ELAC2 are less common in Japanese than in Caucasians, both variants confer significantly increased risk of prostate cancer in Japanese. Carriage of these variants was not associated with age at diagnosis, tumor stage, or tumor grade in these Japanese prostate cancer patients. The allele-specific pattern of risk observed in Japanese and familial Caucasian patients was qualitatively similar; however, the magnitude of that risk was considerably greater in Japanese than in Caucasians. Received: September 3, 2002 / Accepted: October 2, 2002     

Stimulation of nonspecific resistance to infection induced by muramyl dipeptide analogs substituted in the gamma-carboxyl group and evaluation of N alpha-muramyl dipeptide-N epsilon-stearoyllysine.

Stimulation of resistance to infection induced by the analogs of muramyl dipeptide (MDP) having substituted functions in the gamma-carboxyl group of D-isoglutamyl residue was examined in experimental Escherichia coli infections in mice. An MDP analog which is an efficient strengthener of resistance to infection, N alpha-MDP-N epsilon-stearoyllysine [MDP-Lys(L18)], was selected through the comparative assessment of a number of compounds in three categories: (i) gamma-alkylamides, (ii) gamma-esters, and (iii) N alpha-MDP-N epsilon-acyllysine derivatives. Furthermore, the antiinfectious activity of MDP-Lys(L18) was evaluated bacteriologically in comparison with that of MDP. The effect of MDP-Lys(L18) on the susceptibility of mice to infections with various species of microorganisms was studied. Protective activity was greatest against E. coli and staphylococcal infections, considerable against Pseudomonas and Candida infections, and least against Klebsiella infection. The effects of bacterial inoculum size and MDP treatment timing, dose, and route of administration on protective activity were studied. The efficacy of MDP-Lys(L18) in protection tests was demonstrated for all administration routes, even the oral. Its high potency was confirmed by the smaller influence of inoculum size and particularly small value of the minimum dosage required for inducing protective activity. A decrease in bacterial survival was observed in the blood and organs of mice treated with the analog and infected with E. coli. The following two useful effects were obtained: the synergistic effect of glycopeptide and chemotherapeutic agents and the stimulation of resistance to infection in animals immunocompromised by cyclophosphamide treatment.     

Fine structure of the anteromedial eye of the liphistiid spider,Heptathela kimurai

Background: The presence of efferent fibers in the anteromedial eye of liphistiid spiders kept in natural daily cycles of illuminance has been reported. However, this report is limited to innervation by the efferent fiber and daily rhabdomal changes, and there have been no detailed ultrastructural accounts of the eye. Methods: The fine structure of this eye was examined by electron microscopy. Results and conclusions: The eye consists of a cornea, a lens, a vitreous body, and a retina. The retina contains 13 or 14 receptor cells and glial cells. The rhabdoms are distal to the nuclei of the receptor cells. In the distal region of the receptive segment, the rhabdomeres lie in the center of the cell. In the middle region, anisomorphic rhabdoms formed by microvilli from adjacent cells are at the cell periphery. In the proximal region, the rhabdomeres are situated in the center of the cell. The ocellar nerve of the eye runs toward the protocerebrum and enters the posterior part of the first optic ganglion of the secondary eyes. Pigmented cells and nonpigmented cells are observed. The pigmented cells are located in the most lateral of the eye and cover the whole eye. The nonpigmented cells are located in the receptor cell bodies and extend to the origin of the ocellar nerve. They wind to form capillaries filled with electron-dense material. These structures are discussed in comparison with those of other spiders and other chelicerates. © 1994 Wiley-Liss, Inc.     

Origin of hematopoietic progenitors during embryogenesis

It has been widely accepted that hematopoietic and endothelial cell lineages diverge from a common progenitor referred to as the hemangioblast. Recently, analyses of the potential of progenitor cells purified from mouse embryos as well as embryonic stem cells differentiating in vitro resolved intermediate stages between mesodermal cells and committed precursors for hematopoietic and endothelial cell lineages. There are two distinct hematopoietic cell lineages which have different origins, i.e., primitive hematopoietic lineage derived from mesoderm or hemangioblasts and definitive hematopoietic lineage derived from endothelial cells. The endothelium is suggested to provide a milieu in which the definitive hematopoietic lineage acquires multiple potentials.