Diminished energy metabolism and enhanced apoptosis in livers of B6C3F1 mice treated with the antihepatocarcinogen rotenone

Rotenone decreases the incidence of hepatocellular carcinoma and lowers rates of hepatocellular proliferation. In an effort to delineate mechanisms involved, the in vivo effect of rotenone on liver mitochondrial metabolism, apoptotic machinery as well as elements of the hepatic signal transduction pathways were investigated. Mitochondria from livers of male B6C3F1 mice fed a standard diet containing 600 ppm rotenone for 7 days were uncoupled or inhibited when succinate or glutamate plus malate were used as the substrate, respectively. These livers also showed a significant increase in apoptosis compared with control livers. Furthermore, rotenone increased the expression of c-myc mRNA to 5-fold of control values within 3 days, an effect which was still observed (3-fold) after 7 days. Levels of p53 mRNA were also increased 3-fold after 1 day, but declined to control levels by 7 days. Rotenone also caused a transient, yet marked increase in liver particulate glyceraldehyde phosphate dehydrogenase (GAPDH) protein expression, while it did not alter the expression of the cytosolic form of the enzyme. Conversely, mRNA of the proto-oncogene H-ras showed a decline of 35% after 3 days of rotenone treatment, and remained diminished for the duration of the experiment. These data suggest that rotenone may act as an anticancer agent by diminishing mitochondrial bioenergetics which prevents basal hepatocyte proliferation and lowers the threshold for liver cells with DNA damage to undergo apoptosis.

AgNOR counts as a discriminator of lesions of the endocervix

Recently the argyrophil for staining proteins associated with nucleolar organizing regions (AgNORs) has been applied widely in cytohistopathology in various malignancies. Nucleolar organizer region-associated proteins (NORs) are located on the short arm of chromosomes 13, 14, 15, 21 and 22. We applied the technique to 78 cytologic smears from the endocervix stained with the Papanicolaou technique. These included 36 normal endocervical cases, 17 reactive endocervical cases, 19 dysplastic endocervical cases and 6 endocervical adenocarcinoma cases. Statistically significant differences were found between AgNOR counts from normal endocervical smears and smears of endocervical gland dysplasia (P < .001), between normal endocervical smears and smears of endocervical adenocarcinoma (P < .001), between reactive endocervical smears and smears of endocervical gland dysplasia (P < .001) and between reactive endocervical smears and endocervical adenocarcinoma (P < .005). The AgNOR technique appears useful as an adjunct in the diagnosis of endocervical lesions.

Immunocytochemical detection of the 70-kd heat shock protein in alcoholic liver disease

Exposure of cells to physical (eg, heat) or chemical (eg, alcohol) stress results in increased synthesis of a set of highly conserved polypeptides termed heat shock proteins (HSPs), among which the 70-kd protein (HSP 70) is one of the most consistently inducible and highly conserved. This HSP has adenosine triphosphate-binding properties and is known to associate strongly with cytoskeletal structures that are usually disrupted on injury by heat or alcohol. Some HSPs apparently function as accessories to a nonlysosomal, adenosine triphosphate-dependent proteolytic system that binds and digests away stress-generated abnormal or denatured proteins after their conjugation with ubiquitin, a small HSP. Ubiquitin has been demonstrated immunocytochemically in Mallory bodies, which represent mainly degenerated intermediate filaments accumulated in hepatocytes of alcoholic-diseased liver. We immunostained histologic sections from patients with alcoholic liver disease using a polyclonal antibody raised against HSP 70. Strong diffuse cytoplasmic immunoreactivity was observed in many hepatocytes, including cells without Mallory bodies or fatty degeneration. Positive immunoreactivity for HSP 70 points to a possible involvement of this HSP in the pathogenesis of alcoholic liver disease. It also suggests that immunocytochemical detection of HSP 70 may serve as a more sensitive indicator of hepatocellular injury.

The "normal" brain. "Abnormal" ubiquitinilated deposits highlight an age-related protein change

Known morphologic changes that characterize "normal" brain senescence are insufficient to explain the widespread, age-related decline of psychomotor functions. We report that the heavily ubiquitinilated deposits can be consistently detected by immunohistochemistry in the normal senescent brain. Immunostaining of hippocampal sections from aged brains with an anti-ubiquitin antibody was unrelated to neurofibrillary degeneration or senile plaque formation. In contrast, ubiquitin deposits were not detectable in brain sections from neurologically and neuropathologically normal young individuals who had died of nonneurological causes. This finding shows an unrecognized protein change in the normal aged brain.

Concurrent neuroborreliosis and Alzheimer's disease: analysis of the evidence

Several recent reports have claimed a possible association between Borrelia burgdorferi infection and Alzheimer's disease (AD). Herein, we describe our search for additional evidence of neuroborreliosis in AD. Brain tissue from neuropathologically confirmed cases of AD was cultured for B burgdorferi using standard microbiologic methods. Material derived from culture was further examined using electron microscopy, direct immunofluorescence and acridine orange fluorescence. Previous studies have shown high titers of antiborrelia antibodies in CSF in all cases of confirmed neuroborreliosis; therefore, we tested CSF from neuropathologically confirmed cases of AD by indirect immunofluorescence and enzyme-linked immunoassay. In addition, imprint preparations from AD and control brain tissues were studied by direct immunofluorescence using a monoclonal antiborrelia antibody. Finally, a Western blot method was used to analyze protein extracts from cultures and AD brain tissue for the presence of borrelia antigen. Contrary to previous studies, our results do not support an association between infection with B burgdorferi and AD.