Mature dendritic cells infected with canarypox virus elicit strong anti-human immunodeficiency virus CD8+ and CD4+ T-cell responses from chronically infected individuals

Recombinant canarypox virus vectors containing human immunodeficiency virus type 1 (HIV-1) sequences are promising vaccine candidates, as they replicate poorly in human cells. However, when delivered intramuscularly the vaccines have induced inconsistent and in some cases transient antigen-specific cytotoxic T-cell (CTL) responses in seronegative volunteers. An attractive way to enhance these responses would be to target canarypox virus to professional antigen-presenting cells such as dendritic cells (DCs). We studied (i) the interaction between canarypox virus and DCs and (ii) the T-cell responses induced by DCs infected with canarypox virus vectors containing HIV-1 genes. Mature and not immature DCs resisted the cytopathic effects of canarypox virus and elicited strong effector CD8+ T-cell responses from chronically infected HIV+ individuals, e.g., cytolysis, and secretion of gamma interferon (IFN-gamma) and beta-chemokines. Furthermore, canarypox virus-infected DCs were >30-fold more efficient than monocytes and induced responses that were comparable to those induced by vaccinia virus vectors or peptides. Addition of exogenous cytokines was not necessary to elicit CD8+ effector cells, although the presence of CD4+ T cells was required for their expansion and maintenance. Most strikingly, canarypox virus-infected DCs were directly able to stimulate HIV-specific, IFN-gamma-secreting CD4 helper responses from bulk as well as purified CD4+ T cells. Therefore, these results suggest that targeting canarypox virus vectors to mature DCs could potentially elicit both anti-HIV CD8+ and CD4+ helper responses in vivo.

Chymase bound to heparin is resistant to its natural inhibitors and capable of proteolyzing high density lipoproteins in aortic intimal fluid

Degranulated mast cells are present in the human arterial intima. After degranulation of rat serosal mast cells, the secreted neutral serine protease chymase remains bound to the heparin proteoglycan matrix of the exocytosed granules, forming granule remnants. Addition of granule remnants to human aortic intimal fluid results in proteolysis of the apoAI present in the intimal fluid, which contains physiological inhibitors of chymase. To study the physiological mechanism of this protection of granule remnant-bound chymase against its inhibitors, we performed experiments using HDL3 as substrate. Chymase, when bound to the heparin proteoglycans of granule remnants, but not when released from them, resisted inhibition by the mammalian protease inhibitors alpha1-antitrypsin, alpha2-antichymotrypsin, alpha2-macroglobulin, and eglin C. Importantly, the heparin proteoglycan-bound chymase, but not unbound chymase, degraded its inhibitor (alpha1-antitrypsin) in the presence of its substrate (HDL3). Finally, binding to heparin proteoglycans of a physiological inhibitor of chymase (mucus protease inhibitor (MPI)) or of another substrate of chymase (LDL) did not inhibit the degradation of HDL3 by granule remnant-bound chymase. This study demonstrates that binding of chymase to the heparin proteoglycan chains of the exocytosed mast cell granules allows the protease to remain active and degrade HDL3 in the presence of its physiological inhibitors and in the presence of high concentrations of LDL, such as are found in the interstitial fluid of the arterial intima.

Effect of grapefruit juice on pharmacokinetics of microemulsion cyclosporine in African American subjects compared with Caucasian subjects: does ethnic difference matter?

This study aims to determine the effect of grapefruit juice (GJ) on microemulsion cyclosporine (CsA) in 11 African American subjects, and it was compared to those in 11 Caucasian subjects. Each subject received two oral doses of CsA with water (W) or GI as well as i.v. CsA. Regardless of race, GJ significantly increased the peak concentration (Cmax) and area under the time-curve (AUC) of CsA; however, the magnitude of GJ effects was different between African American subjects and Caucasian subjects (p = 0.0003). GJ increased peak concentration of CsA by 39% in African American subjects, while the difference in Caucasian subjects was only 8% (p > 0.05). GJ also increased AUC of CsA in African American subjects by 60%, while GJ increased that in Caucasian subjects by 44% (p = 0.0001). The absolute bioavailability of CsA was 21% lower in African American subjects compared with Caucasian subjects when it was given with water (p = 0.048), but these differences disappeared when it was given with GJ (p = 0.6). These findings suggest that concurrent administration of GJ increases the bioavailability of CsA in African American subjects in greater magnitude compared with Caucasian subjects.

Paclitaxel-induced immune suppression is associated with NF-kappaB activation via conventional PKC isotypes in lipopolysaccharide-stimulated 70Z/3 pre-B lymphocyte tumor cells

Paclitaxel, a potent antitumor agent, has been shown to be lipopolysaccharide (LPS) mimetic in mice, stimulating signaling pathways and gene expression indistinguishably from LPS. In the present study, we showed the intracellular signaling pathway of paclitaxel-induced nuclear factor-kappaB (NF-kappaB) activation and its suppressive effect on LPS-induced signaling in murine 70Z/3 pre-B cells. Stimulation of 70Z/3 cells with LPS for 30 min caused activation of NF-kappaB in the nuclei by detection of DNA-protein binding specific to NF-kappaB. Similarly, paclitaxel also produced a marked and dose-related NF-kappaB activation. However, pretreatment of cells with 10 microM paclitaxel for 18 h resulted in complete inhibition of LPS-mediated NF-kappaB activation. Interestingly, the activity of IkappaB kinase (IKK-beta), which plays an essential role in NF-kappaB activation through IkappaB phosphorylation, was largely enhanced in paclitaxel-treated cells, detected as IkappaBalpha phosphorylation. Because protein kinase C (PKC) is implicated in the activation of NF-kappaB via IKK-beta, the effect of paclitaxel on PKC activation was also measured. It was shown that NF-kappaB nuclear translocation and DNA binding in response to paclitaxel was completely blocked by the conventional PKC inhibitor, Gö 6976. Moreover, immunoblotting analysis with paclitaxel-treated cell extract demonstrated that the conventional PKC isotype PKC-alpha was found to be involved in the regulation of paclitaxel-induced NF-kappaB activation, as determined by electrophoretic mobility shift of PKC. Therefore, these data suggest that paclitaxel may activate IKK-beta via conventional PKC isotypes, resulting in NF-kappaB activation and, finally, desensitization of LPS-inducible signaling pathway in 70Z/3 pre-B cells.

Cytologic distinctions between clinical groups using curette-probe compared to cytology brush

BACKGROUND

We had previously used curette-probe (Rhinoprobe; Arlington Scientific, Springville, UT) to study nasal cytology in various types of patients. Because of the potential sampling ease of using a brush, we sought to compare cytological results obtained with a curette-probe with those obtained using a cytology brush (Cytobrush Plus; Medscand, Malmö, Sweden).

OBJECTIVE

To compare the ability of samples of nasal leukocytes obtained with a curette-probe versus a cytology brush to distinguish clinical categories of patients attending an allergy clinic.

METHODS

Adult allergy clinic patients were studied by both curette-probe and cytology brush sampling. Quantitation of eosinophils and total leukocytes was performed on samples. Comparisons of cell quantities for each sampling method were made in patients classified into clinical groups. Patients with rhinitis complaints and abnormalities of nasal mucosal appearance with or without aeroallergy were compared with other patients. The adjustment of leukocyte quantities for the numbers of epithelial cells observed was also analyzed. Sampling methods were also compared for receiver operating characteristics.

RESULTS

Curette-probe sample leukocyte quantities distinguished patients with symptoms of rhinitis (SR) with abnormal nasal appearance from other patients. This between-group distinction was more significant for leukocyte numbers normalized for the number of epithelial cells. SR patients with both abnormal nasal appearance and aeroallergy had significantly more eosinophils and less goblet cells than other patients. Greater than five curette-probe eosinophils were only observed in patients with SR. Brush samples did not show differences between patients stratified in these ways, and eosinophils were observed in patients without SR. Receiver operating characteristics favored curette-probe samples in terms of leukocyte or eosinophil increases characterizing their respective symptomatic patient subgroups.

CONCLUSIONS

Curette-probe-obtained nasal samples allow for leukocyte and eosinophil quantitations which characterize rhinitis patients better than brush-obtained samples. Total leukocyte quantitations obtained by curette-probe may represent a marker of inflammatory nasal disease in adults undergoing allergy evaluation and treatment for rhinitis.

Effect of overexpression of wild-type and mutant Cu/Zn-superoxide dismutases on oxidative damage and antioxidant defences: relevance to Down's syndrome and familial amyotrophic lateral sclerosis

Patients with Down's syndrome (DS) show elevated levels of copper, zinc-containing superoxide dismutase (SOD1) and appear to have increased lipid peroxidation and oxidative damage to DNA as well as elevated glutathione peroxidase activity. Increasing SOD1 levels by gene transfection in NT-2 and SK-N-MC cell lines also led to a rise in glutathione peroxidase activity, but this was nevertheless accompanied by decreased proliferation rates, increased lipid peroxidation and protein carbonyls, and a trend to a rise in 8-hydroxyguanine and protein-bound 3-nitrotyrosine. Transfection of these cell lines with DNA encoding two mutant SOD1 enzymes (G37R and G85R) associated with familial amyotrophic lateral sclerosis (FALS), produced similar, but more severe changes, i.e. even lower growth rates, higher lipid peroxidation, 3-nitrotyrosine and protein carbonyl levels, decreased GSH levels, raised GSSG levels and higher glutathione peroxidase activities. Since G85R has little SOD activity, these changes cannot be related to increased O(2)(-) scavenging. In no case was SOD2 (mitochondrial Mn-SOD) level altered. Our cellular systems reproduce many of the biochemical changes observed in patients with DS or ALS, and in transgenic mice overexpressing mutant SOD1. They also show the potentially deleterious effects of SOD1 overexpression on cellular proliferation, which may be relevant to abnormal development in DS.

Determination of sildenafil citrate in plasma by high-performance liquid chromatography and a case for the potential interaction of grapefruit juice with sildenafil citrate

This study was designed to establish a simple and reliable assay method that could be routinely used in the clinical laboratory setting using liquid extraction and high-performance liquid chromatography (HPLC). In addition, a case of potential interaction of grapefruit juice with sildenafil citrate is presented. The peaks of sildenafil (measured as sildenafil salt) and internal standard were identified with an ultraviolet detector at 230 nm and detection limit at 10 ng/mL. In a single elderly male patient, grapefruit juice increased the Cmax of sildenafil by 42% (1067.7 ng/mL to 1517.0 ng/mL) although AUC was not significantly altered (4082.9 ng x h/mL to 4171.9 ng x h/mL) by grapefruit juice. Sildenafil could be determined in a simple and reliable method using HPLC with liquid extraction. This case indicated that grapefruit juice might increase the Cmax of sildenafil without significant change in AUC. A further study with an appropriate number of subjects is needed before determining the degree of interaction between grapefruit juice and sildenafil.

Effect of direction of applied mobilization force on the posteroanterior response in the lumbar spine

OBJECTIVE

The purpose of this study was to investigate whether changing the direction of applied force affects measured posteroanterior stiffness and associated pelvic (sacral) and lower thoracic rotations.

DESIGN

A repeated measures design was used.

SETTING

University biomechanical laboratory.

PARTICIPANTS

Twenty-four subjects (14 male, 10 female) with no history of recent low back pain or contraindications to mobilization volunteered for testing.

MAIN OUTCOME MEASURE

Posteroanterior stiffness was assessed at vertebral levels L3 and L5 through use of 3 sagittal plane directions of applied force; the directions differed by 10 degrees. The amount of sacral and lower thoracic rotation that occurred during loading between 30 and 100 N was also recorded.

RESULTS

A small but significant variation of stiffness with direction of applied force was found. At L3, mean stiffness was greatest when the posteroanterior force was applied in a base direction; it was 11% less when the force was applied 10 degrees more caudad than the base direction and 14% less when the force was applied 10 degrees more cephalad than the base direction. There was no significant effect of direction when the force was applied at L5. Both sacral and thoracic rotations displayed significant variation with direction of force when load was applied at L5, with decreasing rotation as the force was applied in a more caudal direction.

CONCLUSION

Posteroanterior stiffness in individuals without back pain is affected by the sagittal plane direction in which the posteroanterior force is applied to the lumbar spine. Remote (thoracic and sacral) movements are also affected by the direction of posteroanterior force. Direction of applied force should therefore be controlled, particularly in the research setting.

Murine cytomegalovirus open reading frame M27 plays an important role in growth and virulence in mice

Using a Tn3-based transposon mutagenesis approach, we have generated a pool of murine cytomegalovirus (MCMV) mutants. In this study, one of the mutants, RvM27, which contained the transposon sequence at open reading frame M27, was characterized both in tissue culture and in immunocompetent BALB/c mice and immunodeficient SCID mice. Our results suggest that the M27 carboxyl-terminal sequence is dispensable for viral replication in vitro. Compared to the wild-type strain and a rescued virus that restored the M27 region, RvM27 was attenuated in growth in both BALB/c and SCID mice that were intraperitoneally infected with the viruses. Specifically, the titers of RvM27 in the salivary glands, lungs, spleens, livers, and kidneys of the infected SCID mice at 21 days postinfection were 50- to 500-fold lower than those of the wild-type virus and the rescued virus. Moreover, the virulence of the mutant virus appeared to be attenuated, because no deaths occurred among SCID mice infected with RvM27 for up to 37 days postinfection, while all the animals infected with the wild-type and rescued viruses died within 27 days postinfection. Our observations provide the first direct evidence to suggest that a disruption of M27 expression results in reduced viral growth and attenuated viral virulence in vivo in infected animals. Moreover, these results suggest that M27 is a viral determinant required for optimal MCMV growth and virulence in vivo and provide insight into the functions of the M27 homologues found in other animal and human CMVs as well as in other betaherpesviruses.

Variation in health and risk behavior among youth living with HIV

Lifetime and current health practices and risk behaviors were examined among 350 youth living with HIV (YLH) aged 14-23 years from four AIDS epicenters (72.6% male; 26.2% African American, 36.9% Latino). YLH were relatively healthy (M CD4 cells = 499), had used substantial health care and were satisfied with the care. YLH's sexual and substance-use histories indicated substantial HIV related risk acts: the median number of lifetime partners was 25 with only 8% using condoms consistently; 14.9% had injected drugs, and 61.2% had used hard drugs. Compared with females, males had more lifetime and recent sexual partners and had used more drugs. Youth who were recently sexually active (81.3%) had multiple partners. Most of the sexually active YLH used condoms consistently (81.6%). YLH who were symptomatic or had an AIDS diagnosis were likely to have recently had more seropositive sexual partners than the asymptomatic youth. Youth disclosed their serostatus to about half of their sexual partners (53.9%). YLH with AIDS used fewer hard drugs than those without an AIDS diagnosis. Health and risk behaviors of the YLH varied significantly based on their disease stage, gender, and ethnicity, suggesting the need for tailoring interventions for subgroups of YLH.

Successful treatment of endobronchial amyloidosis using Nd:YAG laser therapy as an alternative to lobectomy

Endobronchial amyloidosis may cause local obstruction associated with a variety of clinical presentations including recurrent respiratory infection. Although some patients may require surgical intervention, encouraging experience with endobronchial Neodymium (Nd):YAG laser therapy in the management of this condition is reported. Two patients with localized endobronchial amyloidosis were treated with endobronchial Nd:YAG laser therapy. One patient received two treatments for right upper lobe amyloid and another patient received three treatments for right lower lobe amyloid. Excellent clearance of amyloid was achieved in each patient. The first patient remains well, 16 months post-treatment with full patency of the apical and posterior segments. Ten months post-treatment, the second patient has full patency of the right lower lobe. No complications occurred in association with Nd:YAG laser therapy. Endobronchial Neodymium:YAG laser treatment should be considered for selected patients with localized endobronchial obstruction due to amyloidosis.

Forearm vasoreactivity in type 1diabetic subjects

This study compared forearm vasoreactivity in 15 Type I diabetic subjects with 15 healthy controls. The groups were matched for age, exercise capacity, and the absence of other cardiovascular risk factors. Vasoreactivity was measured using strain gauge plethysmography, at rest, after arterial occlusion (OCC), and following OCC coupled with handgrip exercise (ROCC). Forearm blood flows were significantly elevated between conditions 2.58 +/- 0.37ml/100mltissue at rest to 26.80 +/- 6.56 after OCC and 32.80 +/- 8.26ml/100mltissue following ROCC in Type I diabetic subjects. There were no differences in forearm blood flow between groups for any of the conditions. These data indicate the degree of forearm blood flow is directly related to the intensity of the vasodilatory stimulus. However, our study did not reveal evidence of impaired vasodilatory capacity in Type I diabetic subjects compared to controls in the absence of other risk factors.

Effect of the overexpression of wild-type or mutant alpha-synuclein on cell susceptibility to insult

Mutations in alpha-synuclein (A30P and A53T) are involved in some cases of familial Parkinson's disease (FPD), but it is not known how they result in nigral cell death. We examined the effect of alpha-synuclein overexpression on the response of cells to various insults. Wild-type alpha-synuclein and alpha-synuclein mutations associated with FPD were overexpressed in NT-2/D1 and SK-N-MC cells. Overexpression of wild-type alpha-synuclein delayed cell death induced by serum withdrawal or H(2)O(2), but did not delay cell death induced by 1-methyl-4-phenylpyridinium ion (MPP(+)). By contrast, wild-type alpha-synuclein transfectants were sensitive to viability loss induced by staurosporine, lactacystin or 4-hydroxy-2-trans-nonenal (HNE). Decreases in glutathione (GSH) levels were attenuated by wild-type alpha-synuclein after serum deprivation, but were aggravated following lactacystin or staurosporine treatment. Mutant alpha-synucleins increased levels of 8-hydroxyguanine, protein carbonyls, lipid peroxidation and 3-nitrotyrosine, and markedly accelerated cell death in response to all the insults examined. The decrease in GSH levels was enhanced in mutant alpha-synuclein transfectants. The loss of viability induced by toxic insults was by apoptosic mechanism. The presence of abnormal alpha-synucleins in substantia nigra in PD may increase neuronal vulnerability to a range of toxic agents.

Electron-phonon coupling spectrum in photodoped pentacene crystals

The coupling between conduction charges and the vibrational modes of the molecular lattice plays a defining role in the transport characteristics of organic semiconductors. Using electron tunneling spectroscopy, we obtain the electron--optical-phonon coupling spectrum in photodoped pentacene crystals at energies <30 meV. Comparison of the tunneling spectrum to infrared absorption data on the optical phonon density of states yields the energy dependence of the electron-phonon scattering matrix element. The integrated spectral weight of the electron-phonon coupling shows that superconductivity in pentacene is likely of electron-phonon origin.

Additional cytotoxic polyacetylenes from the marine sponge Petrosia species

Ten new polyacetylenic alcohols (1-6, 8-11), along with a known compound, petrocortyne C (7), were isolated from the marine sponge Petrosia sp. The gross structures were established based on NMR and MS data, and the absolute configuration was determined by the modified Mosher's method. These compounds displayed considerable cytotoxicity against a small panel of human solid tumor cell lines. Compounds 1-11 were further evaluated for in vitro inhibitory activity on DNA replication.

Oxygen transfer characteristics in a pilot scale surface aeration vessel with Simcar aerator

The volumetric mass transfer coefficient, KLa, was determined by dynamic method in a surface aerated pilot scale squared vessel up to 0.531 m3 equipped with Simcar type impeller. Through surface aeration, the oxygen transfer characteristics were investigated with the variations of operating variables such as stirring speed, impeller diameter, liquid height and power input per liquid volume (P0/V). It was seen from the results of different oxygen concentration absorption that the dynamic method might lead to errors in KLa when air was used for absorption. To provide reliable KLa values measured by dynamic, the KLa data using pure oxygen were used and confirmed with feeding steady-state method (FSM). As expected, KLa depends on P0/V, impeller size and liquid height. However, for Simcar type impeller, the KLa shows linear dependency on P0/V in contrast to majority of correlations reported in the literature which shows KLa variation of (P0/V)0.65 for disk type impeller. Moreover, it was interesting to find that the bubble behaviors inside the vessel computed by computational fluid dynamics (CFD) could explain qualitatively the KLa changes with operating variables. For the purpose of scale-up procedures, the empirical correlations for predicting KLa were developed within +/- 2% accuracy.

Furazolidone- and nitrofurantoin-resistant Helicobacter pylori: prevalence and role of genes involved in metronidazole resistance

The prevalence of furazolidone, nitrofurantoin, and metronidazole resistance among Helicobacter pylori strains was assessed with 431 clinical isolates. Fifty-two percent were metronidazole resistant, compared to 2% (7 of 431) with resistance to furazolidone and nitrofurantoin. All seven furazolidone- and nitrofurantoin-resistant isolates were also metronidazole resistant. rdxA, frxA, and fdxB knockouts did not result in furazolidone or nitrofurantoin resistance. These data suggest that furazolidone and nitrofurantoin may be good alternatives to metronidazole for treating H. pylori infection.

Identification and characterization of inhibitors of multidrug resistance efflux pumps in Pseudomonas aeruginosa: novel agents for combination therapy

Whole-cell assays were implemented to search for efflux pump inhibitors (EPIs) of the three multidrug resistance efflux pumps (MexAB-OprM, MexCD-OprJ, MexEF-OprN) that contribute to fluoroquinolone resistance in clinical isolates of Pseudomonas aeruginosa. Secondary assays were developed to identify lead compounds with exquisite activities as inhibitors. A broad-spectrum EPI which is active against all three known Mex efflux pumps from P. aeruginosa and their close Escherichia coli efflux pump homolog (AcrAB-TolC) was discovered. When this compound, MC-207,110, was used, the intrinsic resistance of P. aeruginosa to fluoroquinolones was decreased significantly (eightfold for levofloxacin). Acquired resistance due to the overexpression of efflux pumps was also decreased (32- to 64-fold reduction in the MIC of levofloxacin). Similarly, 32- to 64-fold reductions in MICs in the presence of MC-207,110 were observed for strains with overexpressed efflux pumps and various target mutations that confer resistance to levofloxacin (e.g., gyrA and parC). We also compared the frequencies of emergence of levofloxacin-resistant variants in the wild-type strain at four times the MIC of levofloxacin (1 microg/ml) when it was used either alone or in combination with EPI. In the case of levofloxacin alone, the frequency was approximately 10(-7) CFU/ml. In contrast, with an EPI, the frequency was below the level of detection (<10(-11)). In summary, we have demonstrated that inhibition of efflux pumps (i) decreased the level of intrinsic resistance significantly, (ii) reversed acquired resistance, and (iii) resulted in a decreased frequency of emergence of P. aeruginosa strains that are highly resistant to fluoroquinolones.

Effects of N-acetylation degree on N-acetylated chitosan hydrolysis with commercially available and modified pectinases

Three types of N-acetylated chitosans (NACs) with different degrees of acetylation (DA) were prepared and used as a substrate for enzymatic hydrolysis with a commercially available pectinase and a modified one. Pectinase modification was conducted using polyalkyleneoxide-maleic anhydride copolymer (PEO-MA copolymer). The effects of DA on enzymatic reaction with native and modified pectinases were investigated experimentally. Initial hydrolysis rate and Michaelis-Menten kinetic parameters were measured by analysis of reducing sugars. DA of NAC strongly affected the hydrolytic characteristics of native and modified pectinases. N-acetylation of chitosan increased the initial hydrolysis rate and the enzyme-substrate affinity with respect to both pectinases: NACs with DA over 0.3 showed high initial hydrolysis rate and strong affinity between enzyme and substrate. Especially, when NAC with DA over 0.3 was treated with modified pectinase, the affinity became much stronger than the native pectinase.

Formation of cholesterol oxides in irradiated raw and cooked chicken meat during storage

The objective of this study was to determine the effect of electron-beam irradiation on the oxidation of cholesterol in raw and cooked chicken meats with different packaging and storage times. Patties were prepared with skinless chicken breasts and legs. Half of the patties were used for raw meat study and the other half for cooked meat work. For cooked samples, patties were cooked in an electric oven to an internal temperature of 70 C. Raw and cooked meat patties were either aerobically or vacuum-packaged before irradiation. Irradiated patties were stored at 4 C up to 2 wk, and the amounts of cholesterol oxides in the patties were analyzed at 0, 7, and 14 d of storage. In raw chicken meat with vacuum packaging, 7beta-hydroxycholesterol and beta-epoxide were the only two cholesterol oxides present in significant amounts. In raw chicken meat with aerobic packaging, 7alpha-hydroxycholesterol and 7-keiocholesterol, which were not detected in vacuum-packaged raw chicken meat, were found. 7beta-Hydroxycholesterol in raw chicken meat was increased by irradiation and storage time, regardless of packaging. The kinds of cholesterol oxides found in cooked meat were basically the same as those found in raw chicken, but the levels in cooked meats at all storage time were higher than those of the raw meats. With vacuum packaging, irradiation had no consistent effect on the amount of beta-epoxide, 7alpha-hydroxycholesterol, or 7-ketocholesterol, but storage significantly influenced the amount of 7-ketocholesterol, 7beta-hydroxycholesterol, and total cholesterol oxides in cooked chicken meat. With aerobic packaging, irradiation significantly increased the formation of 7alpha-hydroxycholesterol, 7beta-hydroxycholesterol, and 7-ketocholesterol in cooked meat stored for 0 and 7 d. After 14 d of storage, however, irradiation had minor effects on the formation of cholesterol oxides in aerobically packaged cooked chicken.

Difluoromethylornithine is effective as both a preventive and therapeutic agent against the development of UV carcinogenesis in SKH hairless mice

Targeting specific events associated with tumor development represents a rational approach to chemoprevention as well as therapeutic intervention. In this study the ability of difluoromethylornithine (DFMO) to inhibit UV-induced skin carcinogenesis when administered before or after the appearance of tumors was examined. SKH hairless mice were irradiated 3 times per week with 90 mJ/cm(2); this dose was increased by 10% weekly to a maximum of 175 mJ/cm(2). Mice supplied 0.4% DFMO in the drinking water continuously throughout the experiment had an average of 2.0 tumors/mouse (72% incidence) at 30 weeks while controls had an average of 8.2 tumors/mouse (100% incidence). DFMO started after 12 weeks of UV, a time prior to tumor appearance, yielded 3.6 tumors and 100% incidence at 30 weeks. Starting DFMO at 22 weeks, when an average of 2.5 tumors were present, caused regression of tumors for several weeks, followed by a slight rebound. The final tumor number at 30 weeks was 3.0 (96% incidence). Thus, DFMO has strong chemopreventive efficacy, as well as therapeutic activity, against UV-induced skin tumors. Histological and proliferative markers support this conclusion.

Functional gamma-secretase inhibitors reduce beta-amyloid peptide levels in brain

Converging lines of evidence implicate the beta-amyloid peptide (Ass) as causative in Alzheimer's disease. We describe a novel class of compounds that reduce A beta production by functionally inhibiting gamma-secretase, the activity responsible for the carboxy-terminal cleavage required for A beta production. These molecules are active in both 293 HEK cells and neuronal cultures, and exert their effect upon A beta production without affecting protein secretion, most notably in the secreted forms of the amyloid precursor protein (APP). Oral administration of one of these compounds, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester, to mice transgenic for human APP(V717F) reduces brain levels of Ass in a dose-dependent manner within 3 h. These studies represent the first demonstration of a reduction of brain A beta in vivo. Development of such novel functional gamma-secretase inhibitors will enable a clinical examination of the A beta hypothesis that Ass peptide drives the neuropathology observed in Alzheimer's disease.

DNA minor groove interactions and the biological activity of 2,5-bis

2,5-Bis-[4-(N-cyclobutyl-amidino)phenyl] furan and 2,5-bis-[4-(N-cyclohexyl-amidino)phenyl] furan have activity against Pneumocystis carinii and also show cytotoxicity against several tumour cell lines. These activities are correlated with DNA-binding abilities; the crystal structures of complexes with the DNA sequence d(CGCGAATTCGCG) is reported here. Interactions with, and effects on, the DNA minor groove, are found to be factors in the biological properties of these compounds.