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PubMed2002

New plasmid vectors for specific gene targeting in Spiroplasma citri.

In Spiroplasma citri gene inactivation through homologous recombination has been achieved by using the replicative, oriC plasmid pBOT1 as the disruption vector. However, plasmid recombination required extensive passaging of the transformants and, in most cases, recombination occurred at oriC rather than at the target gene. In the current study, we describe a new vector, in which the oriC fragment was reduced to the minimal sequences able to promote plasmid replication. Using this vector to inactivate the motility gene scm1 showed that size reduction of the oriC fragment did increase the frequency of recombination at the target gene. Furthermore, to avoid extensive passaging of the transformants, we developed a strategy in which the selective, tetracycline resistance phenotype can only be expressed once the plasmid has integrated into the chromosome by one single crossover recombination at the target gene. As an example, targeting of the spiralin gene is described.

Base Sequence↗
PubMed1990

Serum concentrations and effects of (+/-)-nicardipine compared with nifedipine in a population of healthy subjects.

The dihydropyridine calcium antagonist (+/-)-nicardipine shares some of the pharmacologic properties of the dihydropyridine prototype nifedipine. To compare them, serum concentrations and cardiovascular effects of 10 mg nifedipine and 20 mg (+/-)-nicardipine were evaluated at 1, 2, and 3 hours after oral intake in a randomized, crossover, single-blind study involving 79 healthy volunteers. (+/-)-Nicardipine serum concentrations were much lower than those of nifedipine, indicating a greater hepatic first-pass metabolism of (+/-)-nicardipine. There was a significant correlation between serum concentrations of both drugs. The frequency distributions of nifedipine and (+/-)-nicardipine AUC (0-3), heart rate increase, and mean arterial pressure decrease showed no bimodality. This does not confirm the proposed polymorphism of nifedipine oxidation. Concentration-effect plots indicate that (+/-)-nicardipine is more potent than nifedipine but shows comparable efficacy in blood pressure reduction.

Adult↗
PubMed1991

Meiotic instability of the R-r complex arising from displaced intragenic exchange and intrachromosomal rearrangement.

The R complex of Zea mays encodes a tissue-specific transcriptional activator of the anthocyanin pigment biosynthetic pathway. Certain R alleles comprise two genetically distinct components that confer the plant (P) and seed (S) aspects of the pigmentation pattern. These alleles are meiotically unstable, losing (P) or (S) function, often accompanied by exchange of flanking markers. We show that the (P) component consists of a single gene within the R-r complex, whereas the (S) component is part of a more complex arrangement of multiple R genes or gene subfragments. A third, cryptic region of the complex, termed (Q), consists of a truncated R sequence. The analysis of R-r crossover derivative alleles shows they arise from unequal exchange between the (P) gene and one of several distinct regions of the R-r complex. Restriction site polymorphisms were used to show that most of these unequal exchanges are intragenic. The frequency of displaced intragenic recombination is comparable to previous estimates for intragenic recombination in maize involving genes that are not duplicated. These exchange events have been used to determine the arrangement of components within the complex and their orientation in the chromosome. We also show that localized rearrangements in the (P) or (S) components are responsible for noncrossover derivative alleles. The organization of R-r has implications for these noncrossover derivatives and models for their origin are discussed.

Anthocyanins↗
PubMed1986

The protective effect of 2-mercapto-ethane sulfonate (MESNA) on hemorrhagic cystitis induced by high-dose ifosfamide treatment tested by a randomized crossover trial.

High-dose ifosfamide (one or two courses of 6 g/m2) with or without mesna was administered to 13 patients with advanced non-small cell lung cancer. The protective effect of 2-mercapto-ethane sulfonate (mesna) against the urotoxic side effects induced by ifosfamide was examined by a randomized crossover trial. A significant reduction in the incidence of hematuria was observed in the patients receiving mesna. Macroscopic hematuria was observed in only one patient who received treatment with mesna versus seven patients treated with ifosfamide alone. Other symptoms, such as frequency and dysuria, tended to be diminished in the patients receiving mesna, although the difference was not statistically significant. Our results suggest that mesna is effective in preventing or diminishing ifosfamide-induced hemorrhagic cystitis. Concomitant use of mesna should allow the administration of a high dose of ifosfamide although more extensive studies are needed to define the optimal dose and schedule of administration of mesna to prevent or attenuate the hemorrhagic cystitis.

Adult↗
PubMed2002

Merging of alpha and slow beta relaxation in supercooled liquids.

Dielectric relaxation spectroscopy (1 Hz - 20 GHz) has been performed on supercooled glass-formers from the temperature of glass transition (T(g)) up to that of melting. Precise measurements particularly in the frequencies of MHz order have revealed that the temperature dependences of secondary beta relaxation times in well above T(g) deviate from the Arrhenius relation below T(g): the beta process does not merge with the alpha process around the dynamical crossover temperature in contradiction to previously speculated extrapolations.

Journal Article↗
PubMed2000

Aging in a relaxor ferroelectric: scaling and memory effects.

A crossover as a function of temperature is found in the zero-field aging properties of the relaxor ferroelectric Pb(Mg(1/3)Nb(2/3))O3. Below a temperature near which nonlinear susceptibility has indicated a suspected phase transition, the time-frequency dependence shows simple scale-independent behavior resembling that for spin glasses. As in spin glasses, high temperature aging is stable as further aging occurs at lower temperature, but not vice versa, indicating hierarchical state arrangement. A more general interpretation of such effects is briefly discussed.

Journal Article↗
PubMed2004

Collective excitations of a degenerate gas at the BEC-BCS crossover.

We study collective excitation modes of a fermionic gas of (6)Li atoms in the BEC-BCS crossover regime. While measurements of the axial compression mode in the cigar-shaped trap close to a Feshbach resonance confirm theoretical expectations, the radial compression mode shows surprising features. In the strongly interacting molecular BEC regime, we observe a negative frequency shift with increasing coupling strength. In the regime of a strongly interacting Fermi gas, an abrupt change in the collective excitation frequency occurs, which may be a signature for a transition from a superfluid to a collisionless phase.

Journal Article↗
PubMed1999

Effect of a mouth rinse containing amyloglucosidase and glucose oxidase on recurrent aphthous ulcers in children and adolescents.

Recurrent aphthous ulcers are one of the most common painful diseases affecting the oral mucosa in children and adults. The aetiology is poorly understood and the treatment thus has for years mostly been symptomatic. However, there has been some promising methods in decreasing the frequency of aphthous ulcer episodes. One of these is the use of a dentifrice containing the combination of the enzymes amyloglucosidase and glucose oxidase (Zendium). The aim of this investigation was, in a pre-study and a double-blind, crossover study, to report if a mouth rinse containing the same enzymes was effective against aphthous ulcers. Thirty-six children and adolescents 7 to 19 years of age took part in the pre-study and thirty-three children and adolescents 7 to 19 years of age took part in the double-blind, crossover study. In both tests the mouth rinses with enzymes resulted in a significant reduction in the number of new aphthous ulcers and pain. In the double-blind, crossover test the 33 children experienced 60 episodes of new ulcers during a 6-month period, including a 3-month period with enzyme rinsings, compared to 221 episodes when rinsing with placebo solution. 55% of the children were completely free from ulcers during the enzyme solution rinsing period followed by a 3-month recovery period compared to 0% when rinsing with placebo. The study confirms earlier studies. Daily rinsing with the enzyme solution can be a recommended treatment to children and adolescents with recurrent aphthous ulcers.

Adolescent↗
PubMed1989

Pulsed field gel electrophoresis identifies a high degree of variability in the number of tandem 21-hydroxylase and complement C4 gene repeats in 21-hydroxylase deficiency haplotypes.

The human steroid 21-hydroxylase gene, CYP21B, and its closely homologous pseudogene, CYP21A, are each normally located centromeric to a complement C4 gene C4B and C4A respectively, in an organization suggesting tandem duplication of a CYP21 + C4 unit. Such an organization has been considered to facilitate gene deletion and addition events by unequal crossover between the tandem repeats. However, the large size (approximately 30 kb) of the individual CYP21 + C4 repeat units together with the difficulty in identifying reliable CYP21A- and CYP21B-specific markers has prevented direct monitoring of gene organization on individual haplotypes by conventional Southern analyses. In the present investigation we have sought to clarify the CYP21 and C4 gene organization in members of 32 British 21-hydroxylase deficiency families by employing additional experimental approaches, notably a long-range restriction mapping approach, which permits assessment through a VNTR type of analysis, of the number of CYP21 and C4 units on individual haplotypes. Our results show that there is a very high frequency (33%) of 21-hydroxylase deficiency haplotypes where functional CYP21B gene sequence has been removed as a consequence of CYP21 + C4 gene deletion while several haplotypes show evidence of gene addition. In each case that we have investigated the gene deletion and gene addition haplotypes differ in length from conventional haplotypes by integral multiples of approximately 30 kb, which strongly supports the involvement of unequal crossover mechanisms. Additionally, the comparatively frequent occurrence of CYP21 fusion genes which contain both CYP21A- and CYP21B-associated markers is suggested by the combined data from Southern analyses, long-range restriction mapping and characterization of selected regions of CYP21 genes which have been amplified in vitro.

Adrenal Hyperplasia, Congenital↗
PubMed2005

No influence on selected parameters of human visual perception of 1970 MHz UMTS-like exposure.

In recent years several studies regarding possible effects of radio frequency (RF) electromagnetic fields (EMFs) on cognitive brain function were reported. In many of these studies on awake humans the working tasks were presented visually to the test subjects, e.g., on a computer screen. Therefore, the question of where in the chain of visual perception, brain processing and response a possible effect could be induced seems to be of interest. In this study, possible effects of exposure to a generic 1.97 GHz UMTS-like signal on human visual perception were investigated in a double blinded, crossover study including 58 healthy volunteer subjects (29 male, 29 female), aged 29 +/- 5.1 years (mean +/- SD). Each test subject underwent a battery of four different clinical tests three times (two different exposure levels and sham exposure) to assess selected parameters of visual perception. The generic signals applied to the subjects' head represented the RF emissions of an UMTS mobile phone under constant receiving conditions and the under condition of strongly varying transmit power, i.e., the signal envelope contained low frequency components. In the high exposure condition the resulting average exposure of the test subjects in the cortex of the left temporal lobe of the brain was 0.63 W/kg (1 g averaged SAR) and 0.37 W/kg (10 g averaged SAR). Low exposure condition was one tenth of high exposure and sham was at least 50 dB (corresponding to a factor of 100,000) below low exposure. Statistical evaluation of the obtained test results revealed no statistically significant differences in the investigated parameters of visual perception between the exposure conditions and sham exposure.

Adult↗
PubMedDate not supplied

Efficacy and safety of once- and twice-daily formulations of molsidomine in patients with stable angina pectoris: double-blind and open-label studies.

Molsidomine, a sydnonimine acting as a heterocyclic direct nitric oxide donor, has been used for many years in several European countries for the treatment of patients with stable angina pectoris. The efficacy and tolerability of a novel once-daily 16-mg formulation of molsidomine (M16) were compared with those of the currently used twice-daily 8-mg molsidomine tablet (M8) in 666 patients. Study 1, a multicenter, randomized, double-blind, placebo-controlled, twin crossover study, involved 533 patients given acute and 2-week treatment with each drug formulation. Study 2, a multicenter, open-label, sequential, add-on trial, compared M16 and M8 in 133 patients. Drug effects on exercise capacity (study 1 only), frequency of anginal attacks and consumption of short-acting itroderivatives, and incidence of adverse events (AEs) were evaluated. Compared with placebo, M16 increased exercise capacity by 15% (P<.001) at the start of study 1 and by 13% (P<.001) after 2 weeks' treatment, and was not inferior to M8. In terms of anginal attack frequency and nitroderivative consumption, M16 was not inferior to M8 in either study. Moreover, compared with M8, M16 produced a statistically and clinically significant reduction in the incidence of anginal attacks in elderly (>/=75 y) but not in younger patients (<75 y) (study 2), nor in patients from study 1. No significant difference from M8 was found in either study in short-acting nitroderivative consumption. No tolerance to M8 or M16 was observed after 2-week treatment. No statistically significant differences in incidences of all AEs and drug-related AEs were observed between M16 and M8 in either study. The same held true for proportions of patients experiencing AEs and drug-related AEs on M16 vs M8: in study 1-14.3% and 11.8% for all AEs (P=.218), 6.9% and 5.4% for drug-related AEs (P=.280); in study 2-1.3% and 1.3% for all AEs, 0% and 1.3% for drug-related AEs (P>.10) in young patients; and in the elderly, 3.6% and 0% for drug-related AEs (P>.10). Only the proportion of elderly patients with all AEs was significantly higher with M16 than with M8: 14.5% vs 1.8% (P=.039). M16 once daily was effective and well tolerated in investigated patients with stable angina pectoris, particularly the elderly, affording 24 hours of therapeutic activity. M16 was not inferior to M8 given twice daily in terms of efficacy, safety profile, and tolerability.

Aged↗
PubMed1987

Antiarrhythmic efficacy of Ethmozine (moricizine HCl) compared with disopyramide and propranolol.

In the investigation of new antiarrhythmic drugs, comparative trials with clinically available antiarrhythmic agents provide a perspective from which to judge the new investigational agent. Two clinical investigations of moricizine HCl, each using a placebo-controlled, double-blind, crossover design, are summarized. In the first study, 18 patients with greater than or equal to 30 ventricular premature complexes (VPCs) per hour (mean 369 +/- 95) were given propranolol (120 mg daily) compared with moricizine HCl (816 +/- 103 mg daily). Propranolol suppressed 38% of VPCs in the study group, moricizine HCl, 81% of VPCs, and the combination of both drugs, 87%. Moricizine HCl was more effective than propranolol in suppressing VPCs at all individual levels greater than 70% (p less than 0.05, McNemar's test). The combination of moricizine HCl and propranolol was well tolerated. The second investigation used a placebo-controlled, double-blind, crossover design to compare the efficacy of disopyramide (600 mg daily) and moricizine HCl (800 mg daily) in 27 patients. Patients had greater than or equal to 40 VPCs/hr on a 24-hour ambulatory electrocardiogram. During moricizine HCl administration, the mean VPC frequency decreased from 524 to 151 VPCs/hr (71.2% reduction). In contrast, disopyramide reduced VPC frequency from 535 to 253 VPCs/hr (52.8% reduction) and demonstrated significantly greater side effects (p less than 0.05). Moricizine HCl was more effective than disopyramide in suppressing VPCs at all individual percent reduction levels greater than 70% (p less than 0.05, McNemar's test). Moricizine HCl was more effective in suppressing VPCs than either disopyramide or propranolol, with significantly fewer side effects.

Adult↗
PubMed1994

Transdermal clonidine for ameliorating post-orchiectomy hot flashes.

To determine the efficacy of transdermal clonidine for alleviating post-orchiectomy hot flashes, a randomized, double-blind, crossover clinical trial was designed including 70 men with a history of prostate cancer who had undergone a medical or surgical orchiectomy and were suffering from hot flashes. The results of this study demonstrated that clonidine did not significantly decrease hot flash frequency or severity. Future research is necessary to find effective means of alleviating hot flashes in post-orchiectomy patients.

Adult↗
PubMed2004

Similar rapid onset of action and magnitude of effect of fexofenadine and cetirizine as assessed by inhibition of histamine-induced wheal-and-flare reaction.

BACKGROUND: Histamine-induced wheal-and-flare studies are useful, objective tests for determining differences in the peripheral H1-receptor blockade activities of antihistamines. OBJECTIVE: To evaluate the time of occurrence of 95% inhibition of histamine-induced wheal and flare after administration of fexofenadine hydrochloride, 180 mg, or cetirizine, 10 mg. METHODS: Forty-two volunteers (aged 18-60 years) were included in a randomized, double-blind, crossover study. Skin prick tests were undertaken using histamine (100 mg/mL) before treatment and 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 hours after treatment. Wheal and flare areas were evaluated, and the time to occurrence of 95% inhibition and the frequency of subjects exhibiting 95% inhibition before median time to 95% inhibition were calculated. RESULTS: Mean +/- SD time to 95% wheal inhibition was 2.46 +/- 0.71 hours with fexofenadine and 2.55 +/- 0.57 hours with cetirizine. The estimated mean difference between fexofenadine and cetirizine (-7 minutes in favor of fexofenadine; 2-sided 95% confidence interval, -21 to +7 minutes) was not statistically significant (P = .34). For wheal, 29% of subjects receiving fexofenadine and 24% receiving cetirizine achieved 95% inhibition before the median time of inhibition (2.5 hours). An exact permutation test yielded a P = .37. For flare, 26% of subjects receiving fexofenadine and 10% receiving cetirizine achieved 95% inhibition before the median time of inhibition (3 hours; P = .12 by exact permutation test). CONCLUSIONS: Fexofenadine and cetirizine have comparable onset of action times and similar frequencies of inhibition, as evaluated by the occurrence of 95% inhibition of histamine-induced wheal and flare.

Adolescent↗
PubMed2000

Effects of the non-selective phosphodiesterase inhibitor pentoxifylline on regional cerebral blood flow and large arteries in healthy subjects.

The vasodilating properties of the non-selective phosphodiesterase (PDE) inhibitor pentoxifylline were evaluated. Pentoxifylline has been reported to increase cerebral blood flow (CBF) and improve recovery rate of stroke patients. Whether these results are due to a dilating effect on arteries or to other mechanisms is not clear. In the present double-blind crossover study, 10 healthy subjects received pentoxifylline 300 mg or placebo intravenously on separate days. Blood flow velocity in the middle cerebral artery (V(mca)) was recorded by transcranial Doppler and rCBF was measured using (133)Xenon-inhalation SPECT. High-frequency ultrasound was used for measurements of temporal and radial artery diameter. Cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) concentrations were assessed in plasma. Except for increased heart rate (P < 0.05), systolic blood pressure (P < 0.05) and plasma cAMP (P < 0.001), no significant differences in CBF, rCBF(mca) or plasma cGMP were seen between placebo and pentoxifylline infusion. During pentoxifylline infusion, V(mca) decreased 7.2% (SD 12.0; P < 0.05) and temporal artery diameter increased 9.0% (SD 7.0; P < 0.001), suggesting minor dilatation of the large arteries. However, this change was not significantly different from placebo. In conclusion, pentoxifylline 300 mg had no effect on rCBF. A possible minor dilatation of the middle cerebral artery and the temporal artery cannot be excluded. Any potential clinical effect of pentoxifylline is most likely mediated through non-vascular mechanisms.

Adult↗
PubMed1998

Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: a pilot study.

Apolipoprotein E (ApoE) genotype was determined in sixty-five subjects who had taken part in a 4-week randomized crossover trial to compare the effect of six mugs of black tea per day v. placebo on blood lipids and blood coagulation factors. Four ApoE genotype variants (seven E2/E3, forty-five E3/E3, twelve E3/E4 and one E4/E4) were found. ApoE allele frequency was within the range typical for Caucasian populations (ApoE-E2 5.4%; ApoE-E3 83.8%; ApoE-E4 10.8%). Individuals bearing at least one E4 allele had substantially higher levels of serum total cholesterol, LDL cholesterol and triacylglycerols. Mean plasminogen activator inhibitor (PAI-1) activity was higher in ApoE-E4 allele-bearing individuals (E3/E4 + E4/E4, 11.89 (SE 1.27) U/ml; E3/E3, 9.19 (SE 0.80) U/ml; E2/E3, 7.21 (SE 1.04) U/ml, P values of E4-group v. E3 and E2 being respectively 0.093 and 0.030). These unexpected findings imply that elevated PAI-1 activity may be a hitherto unrecognized additional factor involved in the increased cardiovascular disease risk associated with apoE-E4 allele. The interactions between tea drinking and genotype were also examined. In the E3/E3 homozygotes, HDL-cholesterol was significantly reduced in the tea period (mean placebo 1.54 mmol/l v. mean tea 1.50 mmol/l, P = 0.027). In the E2/E3 group, triacylglycerol concentration was significantly reduced (mean placebo 1.18 mmol/l v. mean tea 1.09 mmol/l, P = 0.039). Tea also caused a significant decrease of PAI-1 activity in the subjects with E2/E3 genotype (mean placebo 7.21 U/ml v. mean tea 5.88 U/ml, P = 0.007). In the other two genotype groups, there was no significant effect of tea. The results indicate that tea drinking has a beneficial effect on some cardiovascular disease risk-associated factors, especially in E2 allele-bearing individuals. Dietary intervention may be particularly effective in population groups with certain genetic characteristics.

Adult↗
PubMed2004

Comparison of homeopathy, placebo and antibiotic treatment of clinical mastitis in dairy cows - methodological issues and results from a randomized-clinical trial.

Based on the widespread use of homeopathy in treatment of animal disease and the poor documentation of its possible effects and consequences, a clinical trial was carried out in order to evaluate the efficacy of homeopathy in treatment of clinical mastitis in dairy cows and a design for clinical studies on homeopathic treatment, taking into account the guidelines for randomized-clinical trials (RCT) as well as the basic principles of homeopathy. A three-armed, stratified, semi-crossover design comparing homeopathy, placebo and a standardized antibiotic treatment was used. Fifty-seven dairy cows were included. Evaluation was made by two score scales, with score I measuring acute symptoms and score II measuring chronic symptoms, and by recording the frequencies of responders to treatment based on four different responder definitions. Significant reductions in mastitis signs were observed in all treatment groups. Homeopathic treatment was not statistically different from either placebo or antibiotic treatment at day 7 (P = 0.56, P = 0.09) or at day 28 (P = 0.07, P = 0.35). The antibiotic treatment was significantly better than placebo measured by the reduction in score I (P < 0.01). Two-thirds of the cases both in the homeopathy and placebo groups responded clinically within 7 days. The outcome measured by frequencies of responders at day 28 was poor in all treatment groups. Evidence of efficacy of homeopathic treatment beyond placebo was not found in this study, but the design can be useful in subsequent larger trials on individualized homeopathic treatment.

Animals↗
PubMed2001

Exhaled nitric oxide and hydrogen peroxide in patients with chronic obstructive pulmonary disease: effects of inhaled beclomethasone.

There is controversy about the role of inhaled corticosteroids in chronic obstructive pulmonary disease (COPD). Although they appear to have little impact on airways obstruction or its progression, their use may reduce the frequency and/or severity of exacerbations in a subset of patients. We undertook the following study to determine the impact of inhaled corticosteroid on two noninvasive markers of airways inflammation. We assigned 20 stable nonsmoking patients with COPD in random, double-blind crossover fashion to two 2-wk treatment periods with inhaled beclomethasone 500 microg twice daily or matching placebo, followed by a 2-wk washout period. We measured exhaled nitric oxide (ENO), breath condensate H(2)O(2), and flow volume spirometry at weekly intervals. Median baseline ENO was 26.2 (19.3 to 54.8) ppb and fell significantly following 1 and 2 wk of beclomethasone (-10.6 ppb, p = 0.002, and -6.3 ppb, p = 0.013, respectively) but was unchanged by placebo inhalation. Breath condensate H(2)O(2) levels did not change significantly with inhaled beclomethasone or placebo. Although there were no significant changes in FEV(1) with BDP therapy, there was a moderate inverse correlation between changes in ENO and changes in FEV(1) (r -0.50). We conclude that inhaled beclomethasone reduces ENO levels in stable nonsmoking patients with COPD, a finding compatible with an antiinflammatory mechanism of action.

Administration, Topical↗