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.

Murine cytomegalovirus containing a mutation at open reading frame M37 is severely attenuated in growth and virulence in vivo

A pool of murine cytomegalovirus (MCMV) mutants was generated by using a Tn3-based transposon mutagenesis procedure. One of the mutants, RvM37, which contained the transposon sequence at open reading frame M37, was characterized both in tissue culture and in immunocompetent BALB/c and immunodeficient SCID mice. Our results provide the first direct evidence to suggest that M37 is not essential for viral replication in vitro in NIH 3T3 cells. Compared to the wild-type strain and a rescued virus that restored the M37 region, the viral mutant was severely attenuated in growth in both BALB/c and SCID mice after intraperitoneal infection. Specifically, titers of the Smith strain and rescued virus in the salivary glands, lungs, spleens, livers, and kidneys of the SCID mice at 21 days postinfection were about 5 x 10(5), 2 x 10(5), 5 x 10(4), 5 x 10(3), and 1 x 10(4) PFU/ml of organ homogenate, respectively; in contrast, titers of RvM37 in these organs were less than 10(2) PFU/ml of organ homogenate. Moreover, the virulence of the mutant virus appeared to be significantly attenuated because none of the SCID mice infected with RvM37 had died by 120 days postinfection, while all animals infected with the wild-type and rescued viruses had died by 26 days postinfection. Our results suggest that M37 probably encodes a virulence factor and is required for MCMV virulence in SCID mice and for optimal viral growth in vivo.

Inhibition of polyunsaturated fatty acid accumulation in plants expressing a fatty acid epoxygenase

Earlier, we described the isolation of a Crepis palaestina cDNA (Cpal2) which encoded a Delta12-epoxygenase that could catalyse the synthesis of 12,13-epoxy-cis-9-octadecenoic acid (18:1E) from linoleic acid (18:2). When the Cpal2 gene was expressed under the control of a seed-specific promoter in Arabidopsis, plants were able to accumulate small amounts 18:1E and 12,13-epoxy-cis-9,15-octadec-2-enoic acid in their seed lipids. In this report we give results obtained from a detailed analysis of transgenic Arabidopsis plants containing the Cpal2 gene. The seeds from these plants accumulate varying levels of 18:1E, but show a marked increase in 18:1 and equivalent decrease in 18:2 and 18:3. We further observed that the co-expression of a C. palaestina Delta12-desaturase in Arabidopsis appears to return the relative proportions of the C(18) seed fatty acids to normal levels and results in a 2-fold increase in total epoxy fatty acids.

Expression of progesterone receptor in human keratinocytes

Despite the various responses of human skin to female sex hormones, cellular and subcellular targets and the mechanisms of action of estrogen and progesterone in human skin are not well understood. The detection of estrogen receptor (ER) and progesterone receptor (PR) in the skin is of great importance to understand the effect of estrogen and progesterone. In primary cultures of human keratinocytes, expression of ER and PR was monitored by immunocytochemistry and reverse transcriptase polymerase chain reaction (RT-PCR). Paraffin embedded skin tissues were stained with monoclonal antibodies to human ER and PR by immunohistochemistry. Cultured human keratinocytes expressed cytoplasmic PR protein and PR mRNA transcripts. By contrast, ER was detected only at the mRNA level. Suprabasal keratinocytes from samples of pruritic urticarial papules, plaques of pregnancy (PUPPP) and psoriasis were stained positively only for PR, while those from samples of erythema nodosum were negative for both ER and PR. Lesional epidermis of PUPPP showed positive PR immunoreactivity, while nonlesional epidermis did not. No other cells in the normal human skin were stained with ER and PR. The present study suggests that by expressing PR human keratinocytes act as targets for progesterone action.

Direct regulation of the Microphthalmia promoter by Sox10 links Waardenburg-Shah syndrome (WS4)-associated hypopigmentation and deafness to WS2

The transcription factor Sox10 is genetically linked with Waardenburg syndrome 4 (WS4) in humans and the Dominant megacolon (Dom) mouse model for this disease. The pigmentary defects observed in the Dom mouse and WS4 are reminiscent of those associated with mutations in the microphthalmia (Mitf) gene, which encodes a transcription factor essential for the development of the melanocyte lineage. We demonstrate here that wild type Sox10 directly binds and activates transcription of the MITF promoter, whereas a mutant form of the Sox10 protein genetically linked with WS4 acts as a dominant-negative repressor of MITF expression and can reduce endogenous MITF protein levels. The ability of Sox10 to activate transcription of the MITF promoter implicates Sox10 in the regulation of melanocyte development and provides a molecular basis for the hypopigmentation and deafness associated with WS4.

Degradable polymeric carrier for the delivery of IL-10 plasmid DNA to prevent autoimmune insulitis of NOD mice

Recently, we have reported that biodegradable poly [alpha-(4-aminobutyl)-L-glycolic acid] (PAGA) can condense and protect plasmid DNA from DNase I. In this study, we investigated whether the systemic administration of pCAGGS mouse IL-10 (mIL-10) expression plasmid complexed with PAGA can reduce the development of insulitis in non-obese diabetic (NOD) mice. PAGA/mIL-10 plasmid complexes were stable for more than 60 min, but the naked DNA was destroyed within 10 min by DNase I. The PAGA/DNA complexes were injected into the tail vein of 3-week-old NOD mice. Serum mIL-10 level peaked at 5 days after injection, and could be detected for more than 9 weeks. The prevalence of severe insulitis on 12-week-old NOD mice was markedly reduced by the intravenous injection of PAGA/DNA complex (15.7%) compared with that of naked DNA injection (34.5%) and non-treated controls (90.9%). In conclusion, systemic administration of pCAGGS mIL-10 plasmid/PAGA complexes can reduce the severity of insulitis in NOD mice. This study shows that the PAGA/DNA complex has the potential for the prevention of autoimmune diabetes mellitus. Gene Therapy (2000) 7, 2099-2104.

Calculating structures and free energies of complex molecules: combining molecular mechanics and continuum models

A historical perspective on the application of molecular dynamics (MD) to biological macromolecules is presented. Recent developments combining state-of-the-art force fields with continuum solvation calculations have allowed us to reach the fourth era of MD applications in which one can often derive both accurate structure and accurate relative free energies from molecular dynamics trajectories. We illustrate such applications on nucleic acid duplexes, RNA hairpins, protein folding trajectories, and protein-ligand, protein-protein, and protein-nucleic acid interactions.

Surgical treatment of intractable epilepsy accompanying cortical dysplasia

OBJECT

Surgical treatment of cortical dysplasia (CD) together with intractable seizures is challenging because both visualization and localization of the lesion are difficult, correlation with seizure foci requires comprehensive study, and the surgical outcomes reported thus far are unsatisfactory. The authors report their experience in the surgical treatment of CD classified according to a surgical point of view.

METHODS

The definition of CD used in this study was a dysplastic lesion visible on magnetic resonance (MR) images or a lesion that, although not visible on MR images, was diagnosed as moderate-to-severe dysplasia by using pathological analysis. During the last 4.5 years, the authors treated 36 patients with intractable epilepsy accompanied by CD. They divided the 36 cases of CD into four characteristic groups: Group A, diffuse bilateral hemispheric dysplasia; Group B, diffuse lobar dysplasia; Group C, focal dysplasia; and Group D, a moderate to severe degree of CD with a normal appearance on MR images. All but one patient in Group C were monitored in the epilepsy monitoring unit by using subdural electrodes for seizure localization and functional mapping. The incidence of CD among a cohort of 291 patients who had undergone epilepsy surgery at the authors' center during the study period was 12.4%. The mean age of the 36 patients was 21.3 years and the mean age at seizure onset was 8.5 years. The mean follow-up period was 26 months. Twenty-six patients (72.2%) belonged to Engel Class I or II (20 and six, respectively). There were five cases in Group A, nine in Group B, nine in Group C, and 13 in Group D. Patients in Groups A and B were significantly younger at seizure onset and had significantly poorer surgical outcomes compared with patients in Groups C and D (p < 0.05). If outcome is compared on the basis of the extent of removal of CD, patients in whom CD was completely removed had significantly better outcomes than those in whom CD was only partially removed (p < 0.001).

CONCLUSIONS

The authors conclude that intractable epilepsy accompanied by CD can be treated surgically using comprehensive preoperative approaches. Deliberate resective procedures aimed at complete removal of dysplastic tissue ensure excellent seizure control without permanent neurological deficit.

Occupation and adult gliomas

Lifetime job histories from a population-based, case-control study of gliomas diagnosed among adults in the San Francisco Bay area between August 1991 and April 1994 were evaluated to assess occupational risk factors. Occupational data for 476 cases and 462 controls were analyzed, with adjustment for age, gender, education, and race. Imprecise increased risks were observed for physicians and surgeons (odds ratio (OR) = 3.5, 95% confidence interval (CI): 0.7, 17.6), artists (OR = 1.9, 95% CI: 0.5, 6.5), foundry and smelter workers (OR = 2.6, 95% CI: 0.5, 13.1), petroleum and gas workers (OR = 4.9, 95% CI: 0.6, 42.2), and painters (OR = 1.6, 95% CI: 0.5, 4.9). Legal and social service workers, shippers, janitors, motor vehicle operators, and aircraft operators had increased odds ratios only with longer duration of employment. Physicians and surgeons, foundry and smelter workers, petroleum and gas workers, and painters showed increased risk for both astrocytic and nonastrocytic tumors. Artists and firemen had increased risk for astrocytic tumors only, while messengers, textile workers, aircraft operators, and vehicle manufacturing workers showed increased risk only for nonastrocytic tumors. Despite study limitations, including small numbers for many of the occupational groups, a high percentage of proxy respondents among cases, and lack of specific exposure information, associations were observed for several occupations previously reported to be at higher risk for brain tumors generally and gliomas specifically.

Isolation and characterization of tetracycline-resistant clinical isolates of Helicobacter pylori

Tetracycline is an important component of combination therapies for Helicobacter pylori eradication. Twenty-nine tetracycline-resistant isolates requiring MICs ranging from 4 to 16 microgram/ml were isolated from Korean (22 of 460) and Japanese (7 of 105) patients. Interestingly, all of the 29 tetracycline-resistant isolates exhibited cross-resistance to metronidazole, and the cross-resistance was transferred to tetracycline-sensitive H. pylori strains.