Cytonuclear interactions modulate the plasticity of photosynthetic rhythmicity and growth in wild barley

In plants, the contribution of the plasmotype (mitochondria and chloroplast) in controlling the circadian clock plasticity and possible consequences on cytonuclear genetic makeup have yet to be fully elucidated. A genome-wide association study in the wild barley (Hordeum vulgare ssp. spontaneum) B1K collection identified overlap with our previously mapped DRIVERS OF CLOCKS (DOCs) loci in wild-cultivated interspecific population. Moreover, we identified non-random segregation and epistatic interactions between nuclear DOCs loci and the chloroplastic RpoC1 gene, indicating an adaptive value for specific cytonuclear gene combinations. Furthermore, we show that DOC1.1, which harbours the candidate SIGMA FACTOR-B (SIG-B) gene, is linked with the differential expression of SIG-B and CCA1 genes and contributes to the circadian gating response to heat. High-resolution temporal growth and photosynthesis measurements of B1K also link the DOCs loci to differential growth, Chl content and quantum yield. To validate the involvement of the Plastid encoded polymerase (PEP) complex, we over-expressed the two barley chloroplastic RpoC1 alleles in Arabidopsis and identified significant differential plasticity under elevated temperatures. Finally, enhanced clock plasticity of de novo ENU (N-Ethyl-N-nitrosourea) -induced barley rpoB1 mutant further implicates the PEP complex as a key player in regulating the circadian clock output. Overall, this study highlights the contribution of specific cytonuclear interaction between rpoC1 (PEP gene) and SIG-B with distinct circadian timing regulation under heat, and their pleiotropic effects on growth implicate an adaptive value.

The effectiveness of once-daily dosing of inhaled flunisolide in maintaining asthma control

OBJECTIVE

The purpose of this study was to evaluate the feasibility of switching to once-daily (qd) administration of flunisolide in patients with asthma that was controlled by twice-daily (bid) dosing of this inhaled steroid.

METHODS

Three hundred sixty-six adults and children with bronchial asthma that was controlled with inhaled steroids were recruited for this prospective, double-blind, parallel-group study. After a 4-week, stable baseline period of flunisolide administration, 2 inhalations (500 microg) twice daily, each patient was randomized into one of four 12-week flunisolide treatment groups: group 1, 2 inhalations (500 microg) bid; group 2, 4 inhalations (1000 microg) qd in the morning; group 3, 4 inhalations (1000 microg) qd in the evening; or group 4, 2 inhalations (500 microg) qd in the morning. Outcome measures included morning and evening asthma symptoms (scale of 0 to 3), daytime and nighttime albuterol use, morning and evening peak expiratory flow rate (PEFR), FEV1, and methacholine PC20. In addition, a subset of patients in each group had 24-hour urinary cortisol levels measured before and after randomization.

RESULTS

Outcome measures in the four groups were not significantly different at baseline before randomization. The three groups that received maintenance therapy with flunisolide, 1000 microg daily, did not show significant changes from baseline values and remained comparable in all outcome areas. Asthma control in the group randomized to flunisolide 500 microg qd, however, deteriorated significantly: morning symptoms increased by 0.21 units (48%), evening symptoms increased by 0.15 units (31%), daytime albuterol use increased by 0.42 inhalations per day (37%), nighttime albuterol use increased by 0.48 inhalations per night (91%), morning PEFR decreased by 17.1 L/min (4%), and evening PEFR decreased by 12.6 L/min (3%). There were no significant changes in PC20 or 24-hour urinary cortisol levels in any group.

CONCLUSIONS

For patients with asthma that was stabilized by 2 inhalations of flunisolide (500 microg) bid, switching to 4 inhalations (1000 microg) qd in either the morning or evening is effective in maintaining asthma control. Reducing the dose to 2 inhalations (500 microg) qd in the morning, however, leads to a deterioration in asthma control.

A multicenter double-blind study of controlled-release physostigmine for the treatment of symptoms secondary to Alzheimer's disease. Physostigmine Study Group

OBJECTIVE

A multicenter trial to evaluate the efficacy of controlled-release physostigmine salicylate, a cholinesterase inhibitor, was conducted in 1,111 mild-to-moderate Alzheimer's disease (AD) subjects.

DESIGN

During dose titration, subjects received 18, 24, or 30 mg of physostigmine or placebo daily. After a 2-week washout period, 366 subjects with putative improvement were randomized to receive either placebo or their best dose of physostigmine in a 6-week double-blind trial. Nonresponding patients (439) were randomized to receive in a separate double-blind trial either placebo or their highest tolerated dose of physostigmine. The primary efficacy measures included the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS) and a Clinical Global Impression of Change (CGIC). Secondary measures included the Mini-Mental State Examination and two activities-of-daily-living scales.

RESULTS

At the end of the 6-week double-blind phase, physostigmine-treated patients scored 1.75 points higher than placebo-treated patients on the ADAS (p = 0.003) and 0.26 points higher on the CGIC (p = 0.012) in the intent-to-treat analysis. There was no significant improvement on the secondary outcome measures. Patients failing to respond to physostigmine during the dose titration phase failed to respond on any of the outcome measures during the double-blind period of re-exposure. Common adverse events included nausea, vomiting, diarrhea, and anorexia. There were no significant changes in liver function tests.

CONCLUSION

This study demonstrated statistically significant differences between physostigmine and placebo on both a performance-based cognitive functioning instrument and a clinician's global evaluation. The magnitude of the effect size was small and occurred only in the subset of patients who responded in the initial dose titration study period. Nevertheless, the results suggest that in a subset of patients, physostigmine can induce a degree of cognitive improvement over 6 weeks of treatment.

Oral physostigmine in Alzheimer's disease: effects on norepinephrine and vasopressin in cerebrospinal fluid and plasma

Physostigmine is a cholinesterase inhibitor which enhances central and peripheral cholinergic activity. In this study, we explored in persons with Alzheimer's disease (AD) the effects of an acute dose of physostigmine in patients receiving chronic physostigmine treatment on the activity of the cholinergically regulated noradrenergic and arginine vasopressin (AVP) systems. Specifically, we estimated the effects of sustained release oral physostigmine on central and peripheral noradrenergic and AVP systems by measuring norepinephrine (NE) and AVP in cerebrospinal fluid (CSF) and plasma. Lumbar punctures were performed in both physostigmine and no drug treatment conditions. In some subjects the effects of physostigmine on the plasma AVP response to the osmolar stimulus of a hypertonic saline infusion also were measured. NE concentrations in both CSF and plasma were significantly lower in the physostigmine than in the no drug condition. AVP concentrations did not differ between conditions in either compartment, nor did physostigmine affect the AVP response to hypertonic saline. Physostigmine appears to decrease both central and peripheral noradrenergic activity in AD.