The Italian breast cancer prevention trial with tamoxifen: findings and new perspectives

The Italian Tamoxifen Prevention Study includes 5408 healthy hysterectomized women aged 35-70 years who have been randomized to 20 mg/day of tamoxifen or placebo for 5 years. After 46 months median follow-up, an increased risk of venous vascular events (38 women on tamoxifen vs. 18 women on placebo, P = 0.0053), mainly consisting of superficial phlebitis, has been observed and 41 breast cancers have occurred (19 on tamoxifen vs. 22 on placebo, P = 0.64). However, subgroup analyses indicated a borderline significant reduction of breast cancer among women continuously on estrogen replacement therapy (ERT, mostly transdermal) and receiving tamoxifen, with 8 cases of breast cancer among 390 ERT users on placebo versus 1 case among 362 ERT users on tamoxifen (RR = 0.13, 95% CI = 0.02-1.02). Withdrawal rate (mainly due to menopausal symptoms) differed according to ERT use, with compliance being 78% and 75% at 3 and 5 years, respectively, for women who never took ERT, and 92% and 88% at 3 and 5 years, respectively, for women not on ERT at baseline, but who took ERT at some time during the trial. Pharmacokinetic and pharmacodynamic (surrogate end point biomarkers) studies showed that a lower dose of tamoxifen (such as 5 mg/day) does not affect the drug's activity on several biomarkers of both cardiovascular and breast cancer risk. We are therefore planning a multicenter placebo-controlled phase III trial in postmenopausal healthy women on hormone replacement therapy (HRT) to test whether the combination of HRT and low-dose tamoxifen retains the benefits while reducing the risks of either agent maintaining a high compliance rate.

Synthesis, ionotropic glutamate receptor binding affinity, and structure-activity relationships of a new set of 4,5-dihydro-8-heteroaryl-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylates analogues of TQX-173

A series of 4,5-dihydro-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylates analogues of TQX-173 (1b), bearing different nitrogen-containing heterocycles at position-8, were synthesized as AMPA receptor antagonists. All the reported compounds were also biologically evaluated for their binding at glycine/NMDA and KA receptors to better assess their selectivity toward the AMPA receptor. Structure-activity relationships (SAR) on these TQX derivatives have evidenced that the precise positioning of the nitrogen atoms and the specific electronic topography of the 8-heteroaromatic ring are both important for the anchoring to the AMPA receptor. In fact, it has been well-established that the presence of a N(3)-nitrogen-containing heterocycle at position-8 of the TQX framework is an essential feature for potent and selective AMPA receptor antagonists. Functional antagonism at both AMPA receptor and NMDA receptor-ion channel complex was evaluated by assessing the ability of some selected compounds to inhibit depolarization induced by 5 microM AMPA or NMDA in mouse cortical wedge preparations.

Use of cultured cells in assessing ethanol toxicity and ethanol-related metabolism

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Terrence M. Donohue, Jr, and Dahn L. Clemens. The presentations were (1) Characterization of single and double recombinant hepatoma cells that express ethanol-metabolizing enzymes, by Terrence M. Donohue, Jr; (2) Inhibition of cell growth by ethanol metabolism, by Dahn L. Clemens; (3) Use of transfected HeLa cells to study the genesis of alcoholic fatty liver, by Andrea Galli and David Crabb; (4) CYP2E1-mediated oxidative stress induces COL1A2 mRNA in hepatic stellate cells and in a coculture system of HepG2 and stellate cells, by Natalia Nieto; (5) Transforming growth factor-alpha secreted from ethanol-exposed hepatocytes contributes to development of alcoholic hepatic fibrosis, by Junji Kato; and (6) Effect of ethanol on Fas-dependent caspase-3 activation and apoptosis in CD4+ T cells, by Shirish S. Barve.

Comparative study of nine Lactobacillus fermentum bacteriophages

AIMS

To investigate the basic properties of six temperate and three virulent phages, active on Lactobacillus fermentum, on the basis of morphology, host ranges, protein composition and genome characterization.

METHODS AND RESULTS

All phages belonged to the Siphoviridae family; two of them showed prolate heads. The host ranges of seven phages contained a common group of strains. SDS-PAGE protein profiles, restriction analysis of DNA and Southern blot hybridization revealed a high degree of homology between four temperate phages; partial homologies were also detected among virulent and temperate phages. Clustering derived from host range analysis was not related to the results of the DNA hybridizations.

CONCLUSION

The phages investigated have common characteristics with other known phages active on the genus Lactobacillus. Sensitivity to viral infection is apparently enhanced by the presence of a resident prophage.

SIGNIFICANCE AND IMPACT OF THE STUDY

These relationships contribute to the explanation for the origin of phage infection in food processes where Lact. fermentum is involved, such as sourdough fermentation.

Presynaptic kynurenate-sensitive receptors inhibit glutamate release

Kynurenic acid is a tryptophan metabolite provided with antagonist activity on ionotropic glutamate and alpha7 nicotinic acetylcholine receptors. We noticed that in rats with a dialysis probe placed in the head of their caudate nuclei, local administration of kynurenic acid (30-100 nM) significantly reduced glutamate output. Qualitatively and quantitatively similar effects were observed after systemic administration of kynurenine hydroxylase inhibitors, a procedure able to increase brain kynurenate concentrations. Interestingly, in microdialysis studies, methyllycaconitine (0.3-10 nM), a selective alpha7 nicotinic receptor antagonist, also reduced glutamate output. In isolated superfused striatal synaptosomes, kynurenic acid (100 nM), but not methyllycaconitine, inhibited the depolarization (KCl 12.5 mM)-induced release of transmitter or previously taken-up [3H]-D-aspartate. This inhibition was not modified by glycine, N-methyl-D-aspartate or subtype-selective kainate receptor agents, while CNQX or DNQX (10 microM), two AMPA and kainate receptor antagonists, reduced kynurenic acid effects. Low concentrations of kynurenic acid, however, did not modify [3H]-kainate (high and low affinity) or [3H]-AMPA binding to rat brain membranes. Finally, because metabotropic glutamate (mGlu) receptors modulate transmitter release in striatal preparations, we evaluated, with negative results, kynurenic acid (1-100 nM) effects in cells transfected with mGlu1, mGlu2, mGlu4 or mGlu5 receptors. In conclusion, our data show that kynurenate-induced inhibition of glutamate release is not mediated by glutamate receptors. Nicotinic acetylcholine receptors, however, may contribute to the inhibitory effects of kynurenate found in microdialysis studies, but not in those found in isolated synaptosomes.

Use of cultured cells in assessing ethanol toxicity and ethanol-related metabolism

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Terrence M. Donohue, Jr, and Dahn L. Clemens. The presentations were (1) Characterization of single and double recombinant hepatoma cells that express ethanol-metabolizing enzymes, by Terrence M. Donohue, Jr; (2) Inhibition of cell growth by ethanol metabolism, by Dahn L. Clemens; (3) Use of transfected HeLa cells to study the genesis of alcoholic fatty liver, by Andrea Galli and David Crabb; (4) CYP2E1-mediated oxidative stress induces COL1A2 mRNA in hepatic stellate cells and in a coculture system of HepG2 and stellate cells, by Natalia Nieto; (5) Transforming growth factor-alpha secreted from ethanol-exposed hepatocytes contributes to development of alcoholic hepatic fibrosis, by Junji Kato; and (6) Effect of ethanol on Fas-dependent caspase-3 activation and apoptosis in CD4+ T cells, by Shirish S. Barve.

Synthesis of a set of ethyl 1-carbamoyl-3-oxoquinoxaline-2-carboxylates and of their constrained analogue imidazo

The synthesis and glycine/NMDA and AMPA receptor affinities of a set of ethyl (+/-) 1-N-carbamoyl-1,2,3,4-tetrahydro-3-oxoquinoxaline-2-carboxylates 1-11 and those of their constrained analogue (+/-) 1,2,3,3a,4,5-hexahydroimidazo[1,5-a]quinoxaline-1,3,4-triones 12-24 are reported. Compounds 1-11 bear a side-chain at position 1 which has been spatially constrained in compounds 12-24. Most of the reported tricyclic derivatives 12-24 showed glycine/NMDA binding activity comparable to that of their corresponding bicyclic analogues 1-11 providing further evidence that the spatial orientation of the side-chain is an important structural requirement for glycine/NMDA receptor antagonists.

Roquefortine C occurrence in blue cheese

Several strains of Penicillium are used for the production of mold-ripened cheeses, and some of them are able to produce mycotoxins. The aims of the research were the determination of roquefortine C and PR toxin in domestic and imported blue cheeses, the identification of the penicillia used as starter, and the investigation of their capacity for producing toxins in culture media. Roquefortine C was always found in the cheeses at levels ranging from 0.05 to 1.47 mg/kg, whereas the PR toxin was never found. The identification of the fungal strains present in the domestic cheeses included Penicillium glabrum, Penicillium roqueforti, and Penicillium cyclopium in the Gorgonzola "dolce" and Penicillium roqueforti in the Gorgonzola "naturale"; in one case, the presence of Penicillium crustosum was observed. The strains isolated from the foreign cheeses belonged to P. roqueforti. The strains were able to produce between 0.18 and 8.44 mg/liter of roquefortine in yeast extract sucrose medium and between 0.06 and 3.08 mg/liter and less than 0.05 mg/liter when inoculated in milk at 20 degrees C for 14 days and 4 degrees C for 24 days, respectively. Linear relations between production of roquefortine in culture media and cheeses did not emerge. PR toxin ranged from less than 0.05 to 60.30 mg/liter in yeast extract sucrose medium and was produced in milk at 20 degrees C from only one strain. The low levels and the relatively low toxicity of roquefortine make the consumption of blue cheese safe for the consumer.

Microbiological quality and shelf life modeling of ready-to-eat cicorino

Growth of the microbial population resident in ready-to-use fresh cut cicorino, a variety of Chichorium intybus, was determined in the various preparation steps with the aim of defining the hazard critical control points. The investigation concerned cut cicorino from two producers. During the process a 1- to 1.5-fold increase of microbial counts was observed, and the retail product showed values of 10(5) to 10(6) CFU/g. The shelf life of the product was kinetically modeled in order to check the effects of storage temperature and assess the microbial indexes most relevant for hygiene and quality of the distributed product. A modified Gompertz function described the kinetics of microbial growth and allowed definition of a stability time and its dependence on temperature. Stability times were of 0.3, 3.7, and 4.7 days at storage temperatures of 20, 10, and 5 degrees C, respectively. Q10 (the fold decrease of stability time for an increase of 10 degrees C) was 3.85. The results from this study may be used to predict the effects of temperatures experienced in the distribution chain on bacterial levels in cicorino.

The transcriptional and DNA binding activity of peroxisome proliferator-activated receptor alpha is inhibited by ethanol metabolism. A novel mechanism for the development of ethanol-induced fatty liver

Fatty acids are ligands for the peroxisome proliferator-activated receptor alpha (PPAR alpha). Fatty acid levels are increased in liver during the metabolism of ethanol and might be expected to activate PPAR alpha. However, ethanol inhibited PPAR alpha activation of a reporter gene in H4IIEC3 hepatoma cells expressing alcohol-metabolizing enzymes but not in CV-1 cells, which lack these enzymes. Ethanol also reduced the ability of the PPAR alpha ligand WY14,643 to activate reporter constructs in the hepatoma cells or cultured rat hepatocytes. This effect of ethanol was abolished by the alcohol dehydrogenase inhibitor 4-methylpyrazole and augmented by the aldehyde dehydrogenase inhibitor cyanamide, indicating that acetaldehyde was responsible for the action of ethanol. PPAR alpha/retinoid X receptor extracted from hepatoma cells exposed to ethanol or acetaldehyde bound poorly to an oligonucleotide containing peroxisome proliferator response elements. This effect was also blocked by 4-methylpyrazole and augmented by cyanamide. Furthermore, in vitro translated PPAR alpha exposed to acetaldehyde failed to bind DNA. Thus, ethanol metabolism blocks transcriptional activation by PPAR alpha, in part due to impairment of its ability to bind DNA. This effect of ethanol may promote the development of alcoholic fatty liver and other hepatic consequences of alcohol abuse.

Collagen type I synthesized by pancreatic periacinar stellate cells (PSC) co-localizes with lipid peroxidation-derived aldehydes in chronic alcoholic pancreatitis

Chronic alcoholic pancreatitis (CAP) is characterized by progressive pancreatic fibrosis and loss of the acinar cell mass, but the pathogenesis of pancreatic fibrosis in the human is poorly understood. It has been recently suggested that lipid peroxidation-derived aldehydes such as 4-hydroxynonenal (HNE) are involved in tissue damage and fibrosis in other organs. The aim of this study was to evaluate the role of oxidative stress in the development of alcohol-induced pancreatic fibrosis in humans, and to assess the contribution of pancreatic periacinar stellate cells (PSC) in the in vivo synthesis of extracellular matrix components during CAP. Lipid peroxidation was evaluated in tissue specimens obtained from patients with CAP who underwent surgical procedures, by immunohistochemistry using a monoclonal antibody directed against HNE-protein adducts. Immunohistochemical determination of collagen type I, alpha-smooth muscle actin (alpha-SMA), and the beta subunit of human platelet-derived growth factor (PDGF-Rbeta) was also performed. In addition, the tissue mRNA expression of procollagen I, PDGF-Rbeta, and transforming growth factor-beta1 (TGF-beta1) was evaluated by in situ hybridization. In CAP, increased formation of HNE-protein adducts was evident in acinar cells adjacent to the interlobular connective tissue that stained positively for collagen type I. HNE staining was absent in normal pancreas. Several non-parenchymal periacinar cells (PSC) underlay the HNE-stained acinar cells. Those PSC stained positively for alpha-SMA and PDGF-Rbeta and showed active synthesis of procollagen type I by in situ expression of the specific mRNAs. The pattern of expression of PDGF-Rbeta mRNA reflected that observed in immunostaining, showing increased amounts of transcripts in PSC. TGF-beta1 mRNA expression was increased in CAP, but transcripts were found in several cell types including PSC, acinar, and ductal cells. These results indicate that significant lipid peroxidation phenomena occur in CAP and that they are associated with active synthesis of collagen by PSC.

Collagen type I synthesized by pancreatic periacinar stellate cells (PSC) co-localizes with lipid peroxidation-derived aldehydes in chronic alcoholic pancreatitis

Chronic alcoholic pancreatitis (CAP) is characterized by progressive pancreatic fibrosis and loss of the acinar cell mass, but the pathogenesis of pancreatic fibrosis in the human is poorly understood. It has been recently suggested that lipid peroxidation-derived aldehydes such as 4-hydroxynonenal (HNE) are involved in tissue damage and fibrosis in other organs. The aim of this study was to evaluate the role of oxidative stress in the development of alcohol-induced pancreatic fibrosis in humans, and to assess the contribution of pancreatic periacinar stellate cells (PSC) in the in vivo synthesis of extracellular matrix components during CAP. Lipid peroxidation was evaluated in tissue specimens obtained from patients with CAP who underwent surgical procedures, by immunohistochemistry using a monoclonal antibody directed against HNE-protein adducts. Immunohistochemical determination of collagen type I, alpha-smooth muscle actin (alpha-SMA), and the beta subunit of human platelet-derived growth factor (PDGF-Rbeta) was also performed. In addition, the tissue mRNA expression of procollagen I, PDGF-Rbeta, and transforming growth factor-beta1 (TGF-beta1) was evaluated by in situ hybridization. In CAP, increased formation of HNE-protein adducts was evident in acinar cells adjacent to the interlobular connective tissue that stained positively for collagen type I. HNE staining was absent in normal pancreas. Several non-parenchymal periacinar cells (PSC) underlay the HNE-stained acinar cells. Those PSC stained positively for alpha-SMA and PDGF-Rbeta and showed active synthesis of procollagen type I by in situ expression of the specific mRNAs. The pattern of expression of PDGF-Rbeta mRNA reflected that observed in immunostaining, showing increased amounts of transcripts in PSC. TGF-beta1 mRNA expression was increased in CAP, but transcripts were found in several cell types including PSC, acinar, and ductal cells. These results indicate that significant lipid peroxidation phenomena occur in CAP and that they are associated with active synthesis of collagen by PSC.

Effects of HDF1 (Ku70) and HDF2 (Ku80) on spontaneous and DNA damage-induced intrachromosomal recombination in Saccharomyces cerevisiae

The Ku heterodimer binds to the ends of double-stranded breaks (DSBs) in DNA, and is involved in nonhomologous end joining. HDF1 and HDF2, which have been identified in Saccharomyces cerevisiae as homologues of the Ku70 and Ku80 proteins of mammals, reduce radiosensitivity only when homologous recombination repair is impaired and, therefore, affect DSB repair via nonhomologous recombination. Although it has been reported that homologous recombination is defective in the hdf1 null mutant, the roles of HDF1 and HDF2 in this process are not completely clear. We investigated the effect of HDF1 and HDF2 on intrachromosomal recombination by measuring rates of deletion between direct repeats caused by spontaneous and DNA damage-induced events (DEL recombination). We found a decrease in spontaneous DEL recombination in both TCY5 (hdf1delta) and TCY6 (hdf2delta) strains, suggesting that HDF1 and HDF2 play a role in homologous recombination. As DEL recombination events may occur by sister chromatid conversion and/or single-strand annealing, which is initiated by DSBs, HDF1 and HDF2 may be required to recruit proteins to the damaged ends so as to promote single-strand annealing. The strains TCY5 and TCY6 are also defective in methylmethane sulfonate (MMS)- and X-ray-induced, but not in UV-induced DEL recombination. This confirms that HDF1 and HDF2 are required for the completion of DEL recombination by single strand annealing.

Collagen type I synthesized by pancreatic periacinar stellate cells (PSC) co-localizes with lipid peroxidation-derived aldehydes in chronic alcoholic pancreatitis

Chronic alcoholic pancreatitis (CAP) is characterized by progressive pancreatic fibrosis and loss of the acinar cell mass, but the pathogenesis of pancreatic fibrosis in the human is poorly understood. It has been recently suggested that lipid peroxidation-derived aldehydes such as 4-hydroxynonenal (HNE) are involved in tissue damage and fibrosis in other organs. The aim of this study was to evaluate the role of oxidative stress in the development of alcohol-induced pancreatic fibrosis in humans, and to assess the contribution of pancreatic periacinar stellate cells (PSC) in the in vivo synthesis of extracellular matrix components during CAP. Lipid peroxidation was evaluated in tissue specimens obtained from patients with CAP who underwent surgical procedures, by immunohistochemistry using a monoclonal antibody directed against HNE-protein adducts. Immunohistochemical determination of collagen type I, alpha-smooth muscle actin (alpha-SMA), and the beta subunit of human platelet-derived growth factor (PDGF-Rbeta) was also performed. In addition, the tissue mRNA expression of procollagen I, PDGF-Rbeta, and transforming growth factor-beta1 (TGF-beta1) was evaluated by in situ hybridization. In CAP, increased formation of HNE-protein adducts was evident in acinar cells adjacent to the interlobular connective tissue that stained positively for collagen type I. HNE staining was absent in normal pancreas. Several non-parenchymal periacinar cells (PSC) underlay the HNE-stained acinar cells. Those PSC stained positively for alpha-SMA and PDGF-Rbeta and showed active synthesis of procollagen type I by in situ expression of the specific mRNAs. The pattern of expression of PDGF-Rbeta mRNA reflected that observed in immunostaining, showing increased amounts of transcripts in PSC. TGF-beta1 mRNA expression was increased in CAP, but transcripts were found in several cell types including PSC, acinar, and ductal cells. These results indicate that significant lipid peroxidation phenomena occur in CAP and that they are associated with active synthesis of collagen by PSC.

Controlled release of swine semen encapsulated in calcium alginate beads

A quick and successful encapsulation method of swine spermatozoa is described: hydroxypropylmethylcellulose and calcium chloride were added to the sampled ejaculate swine sperm (sperm-rich fraction: creamy white) and then this suspension was dropped into an aqueous solution of sodium alginate. In order to obtain different capsule thicknesses, different calcium chloride concentrations were used. The influence of different formulations on in vitro spermatozoa release behavior and on the mechanical properties has been studied. In vitro sperm kinetics (motility and average velocity) have been determined. The results obtained from motility and average velocity tests of treated seminal material are promising, especially if the difficulty of preservation of swine spermatozoa compared to bovine sperm is considered. The different membranes obtained from the different calcium concentrations have had an influence on mechanical properties and on the release profile of spermatozoa from the capsules, and therefore, it is possible to modulate the release rate of the cells.

Amphetamine-induced loss of human dopamine transporter activity: an internalization-dependent and cocaine-sensitive mechanism

The dopamine transporter (DAT) is a target of amphetamine (AMPH) and cocaine. These psychostimulants attenuate DAT clearance efficiency, thereby increasing synaptic dopamine (DA) levels. Re-uptake rate is determined by the number of functional transporters at the cell surface as well as by their turnover rate. Here, we present evidence that DAT substrates, including AMPH and DA, cause internalization of human DAT, thereby reducing transport capacity. Acute treatment with AMPH reduced the maximal rate of [(3)H]DA uptake, decreased AMPH-induced currents, and significantly redistributed the immunofluorescence of an epitope-tagged DAT from the plasma membrane to the cytosol in human embryonic kidney 293 cells. Conversely, DAT inhibitors, such as cocaine, mazindol, and nomifensine, when administered with AMPH, blocked the reduction in [(3)H]DA uptake and the redistribution of DAT immunofluorescence to the cytosol. The reductions of [(3)H]DA uptake and AMPH-induced DAT internalization also were inhibited by coexpression of a dominant negative mutant of dynamin I (K44A), indicating that endocytosis modulates transport capacity, likely through a clathrin-mediated pathway. With this mechanism of regulation, acute application of AMPH would reduce DA uptake not only by direct competition for uptake, but also by reducing the available cell-surface DAT. Moreover, AMPH-induced internalization might diminish the amount of DAT available for DA efflux, thereby modulating the cytotoxic effects of elevated extracellular DA.

The role of hepatic peroxisome proliferator-activated receptors (PPARs) in health and disease

The liver has long been known to respond to exposure to certain chemicals with hyperplasia and proliferation of the peroxisomal compartment. This response is now known to be mediated by specific receptors. The peroxisome proliferator-activated receptors (PPARs) were cloned 10 years ago, and in that interval, have been found to serve as receptors for a number of endogenous lipid compounds, in addition to the peroxisome proliferators that originally led to their study. Three receptors, designated the alpha, delta, and gamma receptors, have been found in mammals. PPARalpha: is the most abundant form found in the liver, with smaller amounts of the delta and gamma forms also expressed there. Kupffer cells, like other macrophages, appear to express the alpha and gamma isoforms. Hepatic stellate cells are reported to express the gamma isoform. PPARalpha knock-out mice fail to undergo peroxisome proliferation when challenged with the proliferators. Moreover, they have severe derangements of lipid metabolism, particularly during fasting, indicating that normal function of the alpha receptors is needed for lipid homeostasis. This in turn suggests that inadequate PPAR-mediated responses may contribute to abnormal fatty acid metabolism in alcoholic and non-alcoholic steatohepatitis. Recent information suggests that PPARgamma receptors may be important in control of the activation state of the stellate cells, and their repression or inactivation may predispose to hepatic fibrosis. The first approved drug that specifically activates PPARgamma, troglitazone, has rarely been found to cause serious liver injury. Although this is likely to represent an idiosyncratic reaction, the medical community will need to be alert to the possibility that activation or blockade of these receptors may cause hepatic dysfunction.

[Videothoracoscopic approach in the treatment of intralobar pulmonary sequestration. Report of a case]

The Authors report on the use of a videothorascopic approach in the treatment of a patient with intralobar bronchopulmonary sequestration. The latter is a rare malformation which more often than not manifests itself in young patients with hemophthisis, recurrent infection and cough. The condition is difficult to diagnose and is often diagnosed intraoperatively. The treatment is surgical resection. The videothorascopic approach was used in a young patient presenting a lesion of the left inferior lobe with polycyclic contours suspected of being an intralobar bronchopulmonary sequestration, along with medical history findings of cough and hyperpyrexia. The approach permitted identification of the lesion in the context of the left inferior lobe, safe identification and section of the abnormal systemic vessel supplying the lesion and subsequent inferior lobectomy. The postoperative course was uneventful and the patient was discharged on postoperative day 5 with an excellent esthetic and functional outcome. The videothorascopic approach should be taken into consideration for the diagnosis and treatment of intralobar bronchopulmonary sequestrations.

Olfactory function evaluated by SPECT

Few articles on neuroimaging techniques in the study of central and peripheral olfactory pathways are present in the literature. By Single Photon Emission Computed Tomography (SPECT), cortical perfusion increment after sensorial stimulation can be evaluated objectively. In the present research, 10 healthy adults underwent SPECT by CER.TO.96 cerebral tomograph, before and after olfactory stimulation with lavender-water. A variable degree of cortical activation was detected in all patients. Gyrus rectus (+24.5%), orbito-frontal cortex (right +26.6%, left +25.6%), and superior temporal (right +9.9%, left +5.5%) cortical areas were always activated. A slight perfusion increase was present in middle temporal (right +3.2%, left +2.1%) and parieto-occipital (right +0.4%, left +2%) regions. Five patients affected by posttraumatic anosmia were also investigated: they showed a perfusion increment markedly inferior to 0.5% in every olfactory area. SPECT is a rather diffused, easily performed technique which yields objective semi-quantitative information on brain perfusion. Hence, it can be regarded as a promising contribution in the fields of smell neurophysiology, clinical olfactometry, and medicolegal queries.

Peroxisome proliferator-activated receptor gamma transcriptional regulation is involved in platelet-derived growth factor-induced proliferation of human hepatic stellate cells

During liver injury, hepatic stellate cells (HSC) acquire a myofibroblast-like phenotype associated with reduction of lipid droplets, increased collagen synthesis, and proliferation. Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates adipocyte differentiation and controls gene transcription in response to various activators including prostanoids and antidiabetic thiazolidinediones. We explored whether the presence of PPARgamma and its transcriptional activity were involved in control of HSC proliferation in vitro. PPARgamma ligands, 15-deoxy-triangle up(1214) prostaglandin J(2) (15d-PGJ(2)) and ciglitizone, significantly decrease platelet-derived growth factor (PDGF)-induced proliferation in activated human HSC and inhibit alpha smooth muscle actin (alpha-SMA) expression during HSC transdifferentiation. Treatment with 9-cis retinoic acid (9-cisRA) and LG268, ligands of the heterodimerization partner retinoic X receptor (RXR), had a negligible effect in PDGF-treated cells but caused a further reduction of proliferation when used in combination with ciglitizone. Transfection experiments with a reporter gene consisting of 3 copies of a PPAR response element (peroxisome proliferator response element [PPRE](3)-tk-luciferase) showed a progressive reduction of PPAR transcriptional activity during plastic-induced HSC transdifferentiation. Cotransfection with human PPARgamma expression vector restored the PPRE(3)-tk-luciferase reporter expression and the increased level of the receptor in activated HSC-inhibited cell proliferation in a dose-dependent manner. Incubation of human PPARgamma-cotransfected HSC with PDGF strongly inhibited luciferase activity and this effect was blocked by the inhibition of the mitogen-activated protein (MAP) kinase signal cascade. Our results indicate that depression of PPARgamma expression and activity is involved in HSC proliferation and that the PPARgamma ligand-mediated activation exerts a previously unrecognized inhibition of PDGF-induced mitogenesis in activated human HSC.

Regeneration of fertile plants from isolated zygotes of rice (Oryza sativa)

A simple mechanical method has been developed which allows the routine isolation of unfertilized and fertilized egg cells from ovules of Japonica and Indica rice varieties. In the experiments described, the majority of the egg cells and zygotes survived the isolation procedure when the donor plants were in a vigorous state. About 40% of the surviving zygotes underwent sustained development when cultured in Millicell inserts with a non-morphogenic rice feeder-cell culture. Nearly all zygote-derived callus cultures regenerated multiple shoots, which could be subsequently rooted with high efficiency. Zygote-derived plantlets matured to fertile plants when transplanted to soil. So far, about 80 independent plants each from the Japonica variety 'Taipei309' and the Indica variety 'IR58' have been regenerated. The potential of this single-cell regeneration system for marker gene-free transformation is discussed.

Production of cyclopiazonic acid by molds isolated from Taleggio cheese

Twenty-seven strains of Penicillium were isolated from the rind of Taleggio, a typical Italian cheese, so that we could test their capacity to produce cyclopiazonic acid (CPA); all strains produced CPA. The production was strongly influenced by the strain variety and growth conditions. Strains incubated at 25 degrees C for 7 days always produced CPA in mannitol broth, with concentrations ranging from 0.02 to 1 microg/ml, whereas only 33% of strains grown in yeast-extract broth produced CPA, with a maximum value of 0.1 microg/ml. In milk, maximum production (1.6 microg/ml) was observed after 14 days of incubation at 25 degrees C. In order to evaluate the presence of the toxin and its capacity for migrating into the cheeses, the rind, the cheese near the rind, and the cores from six Taleggio cheeses were analyzed. CPA was present in five cheeses, with a maximum concentration of 0.25 mg/kg in one rind, and in one cheese, the toxin migrated to the core. A positive correlation between CPA production and surface mold was found.

Antinociceptive activity of a 3(2H)-pyridazinone derivative in mice

The antinociceptive activity of a 3(2H)-pyridazinone derivative (18a) was investigated in mice. 18a administered at doses which did not change either motor coordination or locomotor activity was able to induce antinociceptive effects in four nociceptive tests, the hot plate test, the tail flick test, the writhing test, and the formalin test. In the hot plate and tail flick test, 18a-induced antinociception was observed both after intraperitoneal administration and after intracerebroventricular injection thus indicating 18a has a central site of action. The pretreatment with the opioid antagonist naloxone, the alpha2-antagonist yohimbine or the GABA(B) antagonist CGP 35348 did not change 18a-induced antinociception in the hot plate test and in the tail flick test. Pretreatment with nicotinic antagonist mecamylamine did not change 18a effects either. A reversion of the 18a effects was observed after pretreatment with the muscarinic antagonists atropine and pirenzepine. Binding experiments revealed that 18a binds to muscarinic receptors, suggesting that 18a antinociception is mediated by central muscarinic receptors. The above findings together with the lack of parasympathomimetic cholinergic side effects indicate useful clinical application for this compound.

Cell division transforms mutagenic lesions into deletion-recombinagenic lesions in yeast cells

Cell proliferation has been recognized as an important factor in human and experimental carcinogenesis. Point mutations as well as larger chromosomal rearrangements are involved in the initiation of cancer. In this paper we compared the relative potencies of radiation and chemical carcinogens for inducing point mutations vs. deletions in cell cycle arrested with dividing cells of Saccharomyces cerevisiae. Point mutation substrates and deletion (DEL) recombination substrates were constructed with the genes CDC28 and TUB2 that are required for cell cycle progression through G1 and G2, respectively. The carcinogens ionizing radiation, UV, MMS, EMS and 4-NQO induced point mutations in G1 and in G2 arrested as well as in dividing cells. UV, MMS, EMS and 4-NQO caused very weak if any increases in DEL recombination in G1 or G2 arrested cells, but large increases in dividing cells. When cells treated with carcinogen either in G1 or G2 were allowed to progress through the cell cycle, a time-dependent increase in DEL recombination was seen. Ionizing radiation and the site-specific endonuclease I-SceI, which both directly create double-strand breaks, induced DEL recombination in G1 as well as in G2 arrested cells. In conclusion, UV-, MMS-, EMS- and 4-NQO-induced DNA damage was converted during DNA replication to a lesion capable of inducing DEL recombination which is probably a DNA strand break. Thus, cell proliferation is not necessary to turn DNA alkylation or UV damage into a mutagenic lesion but to convert the damage into a lesion that induces DNA deletions. These results are discussed with respect to mechanisms of carcinogenesis.

L-proline and L-pipecolate induce enkephalin-sensitive currents in human embryonic kidney 293 cells transfected with the high-affinity mammalian brain L-proline transporter

The high-affinity mammalian brain L-proline transporter (PROT) belongs to the GAT1 gene family, which includes Na- and Cl-dependent plasma membrane carriers for neurotransmitters, osmolites, and metabolites. These transporters couple substrate flux to transmembrane electrochemical gradients, particularly the Na gradient. In the nervous system, transporters clear synapses and help to replenish transmitters in nerve terminals. The localization of PROT to specific excitatory terminals in rat forebrain suggests a role for this carrier in excitatory transmission (). We investigated the voltage regulation and electrogenicity of this novel transporter, using human embryonic kidney (HEK) 293 cells stably transfected with rat PROT cDNA. In physiological solutions between -140 and -40 mV, L-proline (PRO) and its six-member ring congener L-pipecolate (PIP) induced inward current. The current-voltage relationship and the variance of current fluctuations were similar for PRO- and PIP-induced current, and the ratio of induced variance to the mean current ranged from 20 to 60 fA. Des-Tyr-Leu-enkephalin (GGFL), a competitive peptide inhibitor of PROT, reduced the rat PROT-associated current to control levels. GGFL alone did not elicit currents, and the GGFL-sensitive substrate-induced current was absent in nontransfected cells. Finally, GGFL inhibited PROT-mediated transport only when applied to the extracellular face of PROT. These data suggest that (1) PROT uptake is electrogenic, (2) individual transporter currents are voltage-independent, and (3) GGFL is a nonsubstrate inhibitor that interacts either with an extracellular domain of PROT or in an externally accessible pore.

4,5-Dihydro-1,2,4-triazolo[1,5-a]quinoxalin-4-ones: excitatory amino acid antagonists with combined glycine/NMDA and AMPA receptor affinity

A series of 4,5-dihydro-1,2,4-triazolo[1,5-a]quinoxalin-4-ones bearing different substituents on the benzo-fused ring and at position 2 were synthesized and biologically evaluated for their binding at glycine/NMDA and AMPA receptors. Most of the reported compounds show combined glycine/NMDA and AMPA receptor binding activity providing further evidences of the structural similarities of the binding pockets of both receptor recognition sites. Moreover, this study has pointed out some differences for the binding at each receptor type. In particular, for the glycine/NMDA receptor-ligand interaction, the presence of a free acidic function at position 2 and an electron-withdrawing substituent(s) nonbulkier than chlorine atom(s) on the benzo-fused moiety is required. Functional antagonism at the NMDA receptor-ion channel complex was also performed on some selected compounds.

Synthesis, glycine/NMDA and AMPA binding activity of some new 2,5,6-trioxopyrazino[1,2,3-de]quinoxalines and of their restricted analogs 2,5-dioxo- and 4,5-dioxoimidazo[1,5,4-de]quinoxalines

The synthesis of some new 1,2,3,5,6, 7-hexahydro-2,5,6-trioxopyrazino[1,2,3-de]quinoxalines 1c-g and of their restricted analogs 2,4,5,6-tetrahydro-2,5-dioxo-1H- 2a-g and 5,6-dihydro-4,5-dioxo-4H-imidazo[1,5,4-de]quinoxalines 3a-d is reported. Compounds 1c-g, 2a-g, and 3a-d were tested for their binding activity at the glycine/NMDA and AMPA receptors. The results show that only the 6,6,6-tricyclic derivatives 1c-g are able to bind to the glycine/NMDA and AMPA receptors, although with lower affinity than the previously reported lead compounds 1a-b. In contrast, the 5,6,6-tricyclic derivatives 2a-g are inactive at both receptors and only one 4,5-dioxoimidazoquinoxaline (3b) displays a weak glycine/NMDA receptor affinity.

High-level expression of rat class I alcohol dehydrogenase is sufficient for ethanol-induced fat accumulation in transduced HeLa cells

The mechanisms by which ethanol causes fatty liver are complex. Reducing equivalents generated during ethanol oxidation inhibit tricarboxylic acid cycle activity and fatty acid oxidation. In addition, ethanol inhibits lipoprotein export and increases fatty acid uptake and lipid peroxidation. To test the role that alcohol metabolism by alcohol dehydrogenase (ADH) has on cellular lipid metabolism, a cell line expressing rat ADH was generated by transducing HeLa cells with an ADH-expressing retrovirus. The cells expressed high levels of ADH protein and had ADH activity similar to that of liver. Exposure of the cells to 20 mmol/L ethanol for 24 hours led to substantial accumulation of free fatty acids and triacylglycerol in the transduced, but not wild-type, HeLa cells. The rate of synthesis of saponifiable lipid was increased significantly by ethanol under these conditions. Ethanol exposure also promoted triacylglycerol accumulation when the cells were incubated with linoleic acid. This was associated with a decrease in the rate at which the cells oxidized 1-[14-C]-linoleic acid. Fat accumulation was not prevented by including alpha-tocopherol in the medium, arguing against a role for lipid peroxidation. However, the presence of methylene blue completely prevented the fat accumulation. This was associated with a return of the elevated lactate/pyruvate ratio toward normal. These data suggest that generation of reducing equivalents by ADH was sufficient to cause fat accumulation in this cell model.

Ethanol-induced alterations of matrix network in the duodenal mucosa of chronic alcohol abusers

Excessive consumption of alcoholic beverages may be associated with gastrointestinal symptoms, including dyspepsia and diarrhoea. It is not clear whether or not chronic alcohol ingestion damages the mucosa of the small intestine. We investigated the effect of chronic alcohol abuse on the duodenal mucosa, and particularly on its extracellular matrix (ECM) network. Duodenal biopsy specimens were obtained during upper gastrointestinal endoscopy from 50 chronic alcoholics without cirrhosis and 10 healthy subjects. Morphological studies were performed by routine histology, immunohistochemistry and electron microscopy. Morphometry of duodenal tissues was performed with a computerized image analyser. No significant duodenal epithelial changes were found in alcoholics, despite an evident reduction in the enterocyte turnover. Myofibroblast-like cells were significantly increased in the villus stroma of alcoholics in comparison to controls. These cells stained positively for desmin, alpha-smooth muscle actin and for several ECM components. In alcohol abusers the thickness of the mucosal basement membrane was greater and the staining for collagen I and III was enhanced both in the basement membrane and in the villus stroma. A higher expression of tenascin was also seen at the base of villi of alcoholics. Chronic alcohol abuse may induce fibrosis of duodenal villi which is associated with a transformation of villus juxta-parenchymal cells into active subepithelial myofibroblast-like cells able to produce different ECM components.

Synthesis of 2-substituted-6,8-dichloro-3,4-dihydro-3-oxo-2H-1,4-benzothiazine-1,1-d ioxides and -1-oxides as glycine-NMDA receptor antagonists

A number of 2-substituted-3,4-dihydro-3-oxo-6,8-dichloro-2H-1, 4-benzothiazine-1,1-dioxides (1-2a-b) and -1-oxides (3-4a-b) bioisosters of RPR 104632 in which the 3-carboxylic group was replaced by a carbonyl group were synthesized. Comparative in vitro pharmacological studies on this series of RPR 104632 analogs were performed using receptor binding assays. None of these compounds showed detectable binding affinity for the glycine-NMDA receptor.

Inhibition of the Mr 70,000 S6 kinase pathway by rapamycin results in chromosome malsegregation in yeast and mammalian cells

The antifungal and immunosuppressive drug rapamycin arrests the cell cycle in G1-phase in both yeast and mammalian cells. In mammalian cells, rapamycin selectively inhibits phosphorylation and activation of p70 S6 kinase (p70(S6K)), a protein involved in the translation of a subset of mRNAs, without affecting other known kinases. We now report that rapamycin causes chromosome malsegregation in mammalian and yeast cells. Chromosome malsegregation was determined by metaphase chromosome analysis of human lymphocytes and lymphoblasts, detection of CREST-positive micronuclei in human lymphoblasts and Chinese hamster embryonic fibroblast (CHEF) cells, and selection of doubly prototrophic cells in a specially constructed yeast strain. The number of ana-telophases with displaced chromosomes and interphase and mitotic cells with an irregular number of centrosomes was also determined in CHEF cells. In quiescent mammalian cells (human lymphocytes and CHEF cells) induced with growth factor to re-enter the cell cycle, rapamycin was effective when cells were exposed at the time of p70(S6K) activation. In yeast, rapamycin was more effective when treatment was started in G1- than in G2-synchronized cells. Cells from ataxia telangiectasia (A-T) patients are characterized by chromosome instability and have recently been found to be resistant to the growth-inhibiting effect of rapamycin. We found that an A-T lymphoblastoid cell line was also resistant to the induction of chromosome malsegregation by rapamycin, but the level of spontaneous aneuploidy was higher than in normal cells. In yeast, the induction of chromosome malsegregation was dependent on the presence of a wild-type TUB2 gene, encoding the beta-subunit of tubulin. The finding that rapamycin acts in different cell types and organisms suggests that the drug affects a conserved step important for proper segregation of chromosomes. One or more proteins required for chromosome segregation could be under the control of the rapamycin-sensitive pathway.

Effect of Salmonella assay negative and positive carcinogens on intrachromosomal recombination in S-phase arrested yeast cells

A wide variety of carcinogens including Ames assay (Salmonella) positive as well as Salmonella negative carcinogens induce intrachromosomal recombination (DEL recombination) in Saccharomyces cerevisiae. We have shown previously that the Salmonella positive carcinogens, ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS) and 4-Nitroquinoline-N-oxide (4-NQO, and the Salmonella negative carcinogens, safrole, benzene, thiourea, carbon tetrachloride, and urethane, induced DEL recombination in growing, in G1 and in G2 arrested yeast cells. Since we found interesting differences in response between dividing and arrested cells, we wanted to find out whether these differences were due to the difference between cell division versus cell cycle arrest or to any particular cell cycle phase. In the present paper we incubated cells in the presence of hydroxyurea (HU) for cell cycle arrest in S-phase and exposed them to the above carcinogens, and plated them onto selective medium to determine DEL and interchromosomal recombination (ICR) frequencies. It was surprising that carbon tetrachloride had no effect on DEL recombination or ICR in HU treated cells even though it induced DEL recombination in G1 and G2 arrested as well as dividing cells. Further experiments are in agreement with the interpretation that carbon tetrachloride was responsible for prematurely pushing G1 cells into S-phase. The consequence of this may be replication on a damaged template which may be responsible for the action of carbon tetrachloride. EMS, MMS, 4-NQO and urethane were more recombinagenic in HU treated cells than in previous experiments with G2 arrested cells. None of the carcinogens appeared to be activated by S9 for either DEL recombination or ICR induction. Furthermore, we only detect cytochrome P-450 in dividing but not in arrested cells, arguing that possible differences in the ability to metabolize the compounds does not explain the observed differences for DEL recombination induction in the different cell cycle phases. We discuss these data in terms of the mechanism of induced DEL recombination and the possible biological activities of these carcinogens.

[Potential of ultrasonography and ultrasonography-guided biopsy in the diagnosis of local recurrence following radical prostatectomy]

INTRODUCTION

[corrected] We investigated the diagnostic role of combined transrectal US (TRUS) and biopsy to detect recurrent cancer after radical prostatectomy, in patients with negative bone scintigraphy and elevated prostate specific antigen (PSA) levels.

MATERIALS AND METHODS

From March, 1997, to May, 1998, we examined 12 patients with persistently detectable serum PSA levels and negative bone scintigraphy. At the time of diagnosis, an average 36 months had elapsed since prostatectomy. Digital rectal examination (DRE) and disease stage at the time of surgery were also considered. Patients age ranged 47 to 83 years (mean: 65). All patients underwent TRUS with a 7.5 MHz biplane probe; biopsy was performed with a 16 G cutting needle. TRUS findings were considered suspicious if the scan showed any unusual hypoechoic tissue adjacent to the bladder neck, in retrotrigone or peri-retroanastomotic site. In these cases a transperineal US-guided biopsy was performed.

RESULTS

The biopsy proved cancer in 10/12 cases (in 12 cases after two biopsies), showing a better diagnostic accuracy than DRE, which poorly distinguished postoperative changes from recurrent or residual cancer.

CONCLUSIONS

The early detection of recurrences after radical prostatectomy in patients with negative bone scintigraphy is feasible when the above examinations are performed in the same order as described: PSA levels, if altered, indicate the patients to be submitted to TRUS. The latter may be falsely negative in some cases because small recurrences may exhibit no findings at US, and therefore US-guided biopsy of peri-retro-anastomotic regions should be always performed too. The recurrence must be confirmed at histology because histologic findings help choose adjuvant treatment and/or radical irradiation.

Acute regulation of norepinephrine transport: I. protein kinase C-linked muscarinic receptors influence transport capacity and transporter density in SK-N-SH cells

Using SK-N-SH cells, we observe that muscarinic acetylcholine receptor activation by methacholine (MCh) rapidly and selectively diminishes l-NE transport capacity (Vmax) with little or no change in norepinephrine (NE) Km and without apparent effects on membrane potential monitored directly under current clamp. Over the same time frame, MCh exposure reduces the density of [3H]nisoxetine binding sites (Bmax) in intact cells but not in total membrane fractions, consistent with a loss of transport capacity mediated by sequestration of transporters rather than changes in intrinsic transport activity or protein degradation. Similar changes in NE transport and [3H]nisoxetine binding capacity are observed after phorbol ester (beta-PMA) treatment. Inhibition of PKC by antagonists and downregulation of PKC by chronic treatment with phorbol esters abolishes beta-PMA-mediated effects but produce only a partial blockade of MCh-induced effects. Neither muscarinic acetylcholine receptor nor PKC activation require extracellular Ca++ to diminish NET activity. In contrast, treatment of cells with the Ca++/ATPase antagonist, thapsigargin in Ca++-free medium, eliminates the staurosporine-insensitive component of MCh regulation. These findings were further corroborated by the ability of [1, 2-bis(o-amino-phenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester application in Ca++-free medium to abolish NET regulation by MCh. Although they may contribute to basal NET expression, we could not implicate CaMKII-, PKA- or nitric oxide-linked pathways in MCh regulation. Together, these findings 1) provide evidence in support of G-protein coupled receptor-mediated regulation of catecholamine transport, 2) reveal intracellular Ca++-sensitive, PKC-dependent and -independent pathways that serve to regulate NET expression and 3) indicate that the diminished capacity for NE transport evident after mAChR and PKC activation involves a redistribution of NET protein.

Patch-clamp and amperometric recordings from norepinephrine transporters: channel activity and voltage-dependent uptake

Transporters for the biogenic amines dopamine, norepinephrine, epinephrine and serotonin are largely responsible for transmitter inactivation after release. They also serve as high-affinity targets for a number of clinically relevant psychoactive agents, including antidepressants, cocaine, and amphetamines. Despite their prominent role in neurotransmitter inactivation and drug responses, we lack a clear understanding of the permeation pathway or regulation mechanisms at the single transporter level. The resolution of radiotracer-based flux techniques limits the opportunities to dissect these problems. Here we combine patch-clamp recording techniques with microamperometry to record the transporter-mediated flux of norepinephrine across isolated membrane patches. These data reveal voltage-dependent norepinephrine flux that correlates temporally with antidepressant-sensitive transporter currents in the same patch. Furthermore, we resolve unitary flux events linked with bursts of transporter channel openings. These findings indicate that norepinephrine transporters are capable of transporting neurotransmitter across the membrane in discrete shots containing hundreds of molecules. Amperometry is used widely to study neurotransmitter distribution and kinetics in the nervous system and to detect transmitter release during vesicular exocytosis. Of interest regarding the present application is the use of amperometry on inside-out patches with synchronous recording of flux and current. Thus, our results further demonstrate a powerful method to assess transporter function and regulation.

Fluctuation analysis of norepinephrine and serotonin transporter currents

Findings from an electrophysiological analysis of neurotransmitter transporters show that transmitter-induced currents are associated with these transporters: For charged transmitters, such as NE and 5-HT, a fraction of the total current is carried by the transmitter itself; however, the transmitter also induces an extra current in analogy to an ligand-gated ion channel. An additional conductance not discussed in this article is the so-called leak, in which neurotransmitter transporters generate an ionic current in the absence of transmitter. Using a combination of flux measurements, voltage clamp, and fluctuation analysis has shown that, for norepinephrine and serotonin transporters, the transmitter-induced current greatly exceeds the transmitter current. Such data can provide an exact measure of the ratio of these charge movements to transmitter translocation at the molecular level, suggesting new strategies to understand neurotransmitter transporters.

Relationship between chronic nasal obstruction and craniofacial growth: an experimental model

The aim of this paper was to verify if the growth of the nasomaxillary complex can be influenced by a purely functional alteration such as nasal obstruction, which was induced experimentally in a genetically controlled animal model. Sixty albino rats were employed. Twenty of them had the right nostril occluded by a synthetic resin; another twenty had both nostrils occluded; the other 20 were taken as control group. When the growth was completed, the rats were sacrificed and cephalometric analysis was carried out. Both treated groups showed a statistically significant reduction in overall weight and height, in the vertical development of the nasomaxillary complex and in the skullbase longitudinal axis. After discussing the literature on the subject, the authors conclude that normal craniofacial growth in the rat must somehow depend on physiological nasal breathing, which should therefore be considered of crucial importance.

Neuro- and ototoxicity of high-dose carboplatin treatment in poor prognosis ovarian cancer patients

BACKGROUND

Hematopoietic toxicity of high-dose carboplatin (HD-CBDCA) chemotherapy can be managed effectively with autologous blood cell support, but no conclusive data are available on its neuro- and ototoxicity.

PATIENTS AND METHODS

We determined the neuro- and ototoxicity of HD-CBDCA in 10 patients affected by advanced ovarian cancer. HD-CBDCA was delivered as 24-hour continuous infusion or as 5-day schedules. Each patient underwent an extended clinical and instrumental neurological and otological evaluation before, during and after treatment.

RESULTS

After HD-CBDCA only 1 patient had a clinically-evident peripheral neuropathy, while 3 additional patients had only distal paresthesias. Neurophysiological examination evidenced mild, although diffuse, sensory nerve impairment. Motor nerve impairment was also occasionally observed. All the sensory and motor pathological changes had a favorable course during the follow-up period. Ototoxicity was more severe than neurotoxicity and, in one case it was dose-limiting and audiologic impairment tended to remain constant also in the follow-up period.

CONCLUSIONS

HD-CBDCA treatment can be tolerated by most of the patients, but careful monitoring of neuro- and, especially, ototoxicity should be planned.

Regulated phosphorylation and trafficking of antidepressant-sensitive serotonin transporter proteins

Presynaptic serotonin (5-hydroxytryptamine, 5-HT) transporters (SERTs) mediate antidepressant-sensitive clearance of 5-HT following release. Although we have been aware for decades that SERT-mediated 5-HT clearance can be modulated by exogenous agents including serotonin-selective reuptake inhibitors, amphetamines, and cocaine, we have had little reason to speculate that SERT activity was actively controlled through endogenous pathways. Recent studies indicate that SERTs are likely to be trafficked to specific plasma membrane subdomains to achieve localized clearance of 5-HT, and that the number of SERTs resident in the plasma membrane is controlled through kinase- and phosphatase-linked pathways. In particular, roles for protein kinase C and phosphatase 2A become apparent through studies with enzyme activators and inhibitors in SERT-transfected cells, where SERT proteins are rapidly phosphorylated in parallel with transporter redistribution and loss of functional uptake capacity. Based on our findings, and the studies of others in native tissues and transfected cells, we propose a model whereby SERTs are organized in a macromolecular complex in the plasma membrane that may serve to locate reuptake activity near release sites. Although many elements of this model remain hypothetical, our findings suggest a much more dynamic picture of transporter-mediated 5-HT reuptake than typically described and suggest opportunities both for the development of new SERT regulatory agents and for the identification of regulatory pathways that may be compromised in mental illness.

Effects of DNA double-strand and single-strand breaks on intrachromosomal recombination events in cell-cycle-arrested yeast cells

Intrachromosomal recombination between repeated elements can result in deletion (DEL recombination) events. We investigated the inducibility of such intrachromosomal recombination events at different stages of the cell cycle and the nature of the primary DNA lesions capable of initiating these events. Two genetic systems were constructed in Saccharomyces cerevisiae that select for DEL recombination events between duplicated alleles of CDC28 and TUB2. We determined effects of double-strand breaks (DSBs) and single-strand breaks (SSBs) between the duplicated alleles on DEL recombination when induced in dividing cells or cells arrested in G1 or G2. Site-specific DSBs and SSBs were produced by overexpression of the I-Sce I endonuclease and the gene II protein (gIIp), respectively. I-Sce I-induced DSBs caused an increase in DEL recombination frequencies in both dividing and cell-cycle-arrested cells, indicating that G1- and G2-arrested cells are capable of completing DSB repair. In contrast, gIIp-induced SSBs caused an increase in DEL recombination frequency only in dividing cells. To further examine these phenomena we used both gamma-irradiation, inducing DSBs as its most relevant lesion, and UV, inducing other forms of DNA damage. UV irradiation did not increase DEL recombination frequencies in G1 or G2, whereas gamma-rays increased DEL recombination frequencies in both phases. Both forms of radiation, however, induced DEL recombination in dividing cells. The results suggest that DSBs but not SSBs induce DEL recombination, probably via the single-strand annealing pathway. Further, DSBs in dividing cells may result from the replication of a UV or SSB-damaged template. Alternatively, UV induced events may occur by replication slippage after DNA polymerase pausing in front of the damage.

High-level expression of RXRalpha and the presence of endogenous ligands contribute to expression of a peroxisome proliferator-activated receptor-responsive gene in hepatoma cells

Genes containing peroxisome proliferator-activated receptor (PPAR) binding sites are both inducible by peroxisome proliferators and expressed in a tissue-specific fashion. A PPAR-responsive reporter gene cotransfected with a PPARalpha expression vector was highly expressed in H4IIEC3 hepatoma cells. Addition of clofibrate resulted in a modest further induction of the reporter gene. In CV-1 cells, high expression of the reporter required the addition of clofibrate. H4IIEC3 cells had higher levels of retinoid X receptor (RXRalpha) than CV-1 cells; cotransfection of CV-1 cells with PPARalpha plus RXRalpha expression plasmids abolished the cell line difference in basal and clofibrate-stimulated expression of the reporter. Lipid extracts of hepatoma cells or of liver or kidney stimulated expression of the reporter; extracts of CV-1 cells were far less effective. Chromatographic analysis of these extracts revealed high levels of three fractions of lipid in liver and H4IIEC3 cells that were lower in CV-1 cells. We conclude that (1) in cells expressing high levels of both RXRs and PPARalpha, such as hepatocytes and kidney cells, these factors are constitutively active; (2) activators of PPARalpha may increase its ability to form heterodimers with RXRs when the latter are limiting; and (3) hepatoma cells, liver, and kidney contain lipid-extractable compounds capable of activating PPARalpha.

A countrywide programme of continuing professional development in Argentina. Argentine Society of Paediatrics, Subcommittee of Continuing Paediatric Education

The Argentinean Society of Paediatrics introduced in 1993 a continuing professional development (CPD) programme to raise standards of clinical practice. The aims of the project were to introduce a structured, distance learning programme accessible to all paediatricians in the country, but especially for those working far from centres of paediatric excellence. The programme is planned on an annual basis. It includes four activities: a written manual designed by a team of medical experts and educationalists comprising 12 topics; field work for participants; annual meetings in several locations in the country for discussion of the subjects; and an evaluation based on centrally designed multiple choice questions distributed by mail. In spite of a registration free of 90 Pounds a year, participation in the programme increased from 3357 in 1993 to 4126 in 1996, from a membership of 10 216 paediatricians in Argentina. The popularity of the programme may result from an appropriate interpretation of professional needs of paediatricians in Argentina, adequate organisational arrangements that reach all colleagues, including those working in remote areas, and a genuine motivation of paediatricians for participating in a learning process.

Bactericidal activity of chlorine dioxide against Escherichia coli in water and on hard surfaces

The efficacy of chlorine dioxide as a disinfectant was evaluated against cells of Escherichia coli ATCC 11229 in aqueous suspension and adhering to the surfaces of stainless steel AISI 304 and PVC. The concentrations tested ranged from 0.7 to 14 mg/liter; the exposure times investigated were 30 s and 1, 2, 4, and 8 min. When the bacteria were suspended in water with 1.4 mg/liter of chlorine dioxide, a 10(5)-fold reduction of the initial viable count occurred within 30 s; when cells were attached to the steel surface, the same rate of inactivation took place only after 6 min with 7 mg/liter or 4 min with 14 mg/liter of chlorine dioxide. A 5-log reduction was not obtained when organisms were adhered to polyvinyl chloride (PVC). Scanning electron microscope micrographs of contaminated surfaces revealed that the PVC was very rough with pores much larger in diameter than the cells. Time values determining a 90% reduction of the E. coli population (90% killing time) were calculated for each concentration of disinfectant tested in suspension and on the steel surface. If the same experimental conditions were strictly adopted, linear functions of the log of bacterial inactivation could be plotted (log 90% killing time versus log concentration of disinfectant). This work showed that results obtained with suspension tests could not be used to estimate disinfection of hard surfaces.

Inhibition of cholinesterase-associated aryl acylamidase activity by anticholinesterase agents: focus on drugs potentially effective in Alzheimer's disease

The potency of a series of anticholinesterase (anti-ChE) agents and serotonin-related amines as inhibitors of the aryl acylamidase (AAA) activity associated with electric eel acetylcholinesterase (AChE) (EC 3.1.1.7) and horse serum butyrylcholinesterase (BuChE) (EC 3.1.1.8) was examined and compared with the potency of the same compounds as ChE inhibitors. Neostigmine, physostigmine, BW 284C51, (+/-)-huperzine A, E2020, tacrine, edrophonium and heptyl-physostigmine were, in that order, the most potent in inhibiting eel AChE-associated AAA activity, their inhibitor constant (Ki) values being in the range 0.02-0.37 microM. The rank order of the same compounds as AChE inhibitors basically paralleled that of AAA, although they were in general stronger on AChE (Ki = 0.001-0.05). The peripheral anionic site inhibitors propidium and gallamine were inactive on AChE-associated AAA. Serotonin and its derivatives were slightly stronger on AAA (Ki = 7.5-30 microM) than on AChE (Ki = 20-140 microM). Tacrine (IC50 = 0.03 microM), diisopropylfluorophosphate (IC50 = 0.04 microM), heptyl-physostigmine (IC50 = 0.11 microM), physostigmine (IC50 = 0.15 microM) and tetra-iso-propylpyrophosphoramide (iso-OMPA) (IC50 = 0.75 microM) were the most potent in inhibiting horse serum BuChE-associated AAA activity. Serotonin and related amines were very weak on BuChE-associated AAA activity. These results indicate that the inhibitory potencies of the active site anti-ChE agents on the AAA activity associated with eel AChE and horse serum BuChE are closely correlated with their action on the respective ChE. In addition, the efficacy of tacrine, E2020, heptyl-physostigmine and (+/-)-huperzine A in the treatment of Alzheimer's disease is unlikely to be related to the action of these drugs on ChE-associated AAA.