Identification of a cellulose synthase-associated protein required for cellulose biosynthesis

Cellulose synthase-interactive protein 1 (CSI1) was identified in a two-hybrid screen for proteins that interact with cellulose synthase (CESA) isoforms involved in primary plant cell wall synthesis. CSI1 encodes a 2,150-amino acid protein that contains 10 predicted Armadillo repeats and a C2 domain. Mutations in CSI1 cause defective cell elongation in hypocotyls and roots and reduce cellulose content. CSI1 is associated with CESA complexes, and csi1 mutants affect the distribution and movement of CESA complexes in the plasma membrane.     

Ultrasound-Induced Mild Hyperthermia as a Novel Approach to Increase Drug Uptake in Brain Microvessel Endothelial Cells

Purpose. Drug delivery to the central nervous system (CNS) is limited by the blood-brain barrier (BBB). Thus, a noninvasive and reversible method to enhance BBB permeation of drugs is highly desirable. In the present work, we studied if ultrasound-induced mild hyperthermia (USHT, 0.4 watts (W)/cm² at 41°C) can enhance drug absorption in BBB endothelial cells, and we elucidated the mechanism of USHT on cellular accumulation. Methods. To accomplish these aims, we studied the effects of hyperthermia (41°C), USHT, P-glycoprotein (P-gp) modulator (PSC 833), and combination of USHT and PSC 833 on accumulation of P-gp substrate (R123) and non-P-gp substrates (sucrose, 2-deoxyglucose, and antipyrine) in monolayers of primary bovine brain microvessel endothelial cells (BBMEC). Results. USHT, through its thermal effect, produces a significant (relative to controls; no USHT) and comparable increase in R123 accumulation with PSC 833. We also demonstrate that USHT increases permeability of hydrophobic (R123 and [¹⁴C]-antipyrine) and not hydrophilic molecules ([¹⁴C]-sucrose and 2-[³H]-deoxy-d-glucose). The enhanced permeability is reversible and size dependent, as USHT produces a much larger effect on cellular accumulation of [¹⁴C]-antitpyrine (molecular weight of 188 D) than that of R123 (molecular weight of 380.8 D). Although USHT increases membrane permeability, it did not affect P-gp activity or the activity of glucose transporters. Conclusions. Our results point to the potential use of USHT as a reversible and noninvasive approach to increase BBB permeation of hydrophobic drugs, including P-gp-recognized substrates.     

A TEM/SEM study of the microbial plaque overlying the necrotic gingival papillae of HIV-seropositive,necrotizing ulcerative periodontitis

The purpose of this study was to examine by transmission (TEM) and scanning electron microscopy (SEM) the supragingival microbial plaque overlying the ulcerated gingival papillae of necrotizing ulcerative periodontitis (NUP) lesions in HIV-seropositive patients. The microbiota of NUP and HIV-seropositive patients with periodontitis has been reported to be similar to that of conventional periodontitis in non-infected subjects, although several investigators have also reported high recovery rates of microbes not generally associated with the indigenous oral microbial flora. Light and electron microscopic observations and microbial culture studies indicate a similar high prevalence of spirochetes in both necrotizing ulcerative gingivitis (NUG) and NUP. In addition, several studies have reported more frequent isolation of Candida albicans from diseased periodontal sites in HIV-seropositive patients than from non-diseased sites. Ten male and six female patients, each HIV-seropositive and exhibiting NUP, constituted the study population. Two biopsies of involved gingival papillae from between posterior teeth were obtained from each patient and processed for examination by both TEM and SEM. Microscopic examination revealed a surface biofilm comprised of a mixed microbial flora of various morphotypes in 81.3% of biopsy specimens. The subsurface flora featured dense aggregations of spirochetes in 87.5% of specimens. Zones of aggregated polymorphonuclear leukocytes and necrotic cells were also noted. Yeasts were observed in 65.6% of specimens and herpes-like viruses in 56.5% of the specimens. Collectively, except for the presence of yeast and viruses, the results suggest that the microbial flora and possibly the soft tissue lesions of NUP and necrotizing ulcerative gingivitis are very similar.     

A preliminary study on oxygen saturation levels of patients during periodontal surgery with and without oral conscious sedation using diazepam

BACKGROUND: Stress and anxiety alter respiratory rate and thereby alter oxygen saturation in the blood. Management of psychological stress in the dental office may help maintain blood gas homeostasis. One method of stress management is through the use of preoperative oral sedation. METHODS: The study population consisted of 13 patients scheduled to receive two quadrants of periodontal surgery at two different appointments. A randomized split-mouth crossover design was used with one quadrant of surgery involving preoperative oral sedation (diazepam) and local anesthetic, and the second using local anesthetic only. Oxygen saturation was monitored by pulse oximetry, which recorded the number of times saturation dropped below 95% in a given time period. Data were recorded at 5 time periods: 1) baseline; 2) from time of anesthetic administration to 20 minutes into surgery; 3) 21 to 40 minutes; 4) 41 to 60 minutes; and 5) 61 to 80 minutes into the surgery. Data were analyzed by a two-factor repeated measures ANOVA. The two within-group factors were treatment group and time. RESULTS: Results indicated no significant interaction between time and treatment (P > .05). However, data for groups over time suggested a trend supporting an interaction. The eta2 value of 0.124 suggested a moderate effect favoring the diazepam treatment. No significant difference was noted for the main effect of treatment and time. However, the eta2 value of 0.24 for treatment effect (diazepam versus no diazepam) suggested a meaningful difference between groups. Similarly the eta2 value of 0.135 for time suggested a moderate effect over time within-subjects. CONCLUSIONS: This study indicates that diazepam given orally in adult dosages does not cause significant respiratory depression, and is generally safe for those healthy patients who may require slight to mild sedation during periodontal surgery.     

Qualitative research: what does it have to offer to the gerontologist?

The growing challenges of promoting health and managing illness in an ever-changing health care system require an arsenal of research approaches. Qualitative methods have a long tradition in disciplines such as sociology and anthropology and are being used with greater frequency as interdisciplinary health-related disciplines attempt to understand and explain complex problems. The purpose of this article is to define and describe the main features of qualitative research and to examine ways in which this methodology is relevant and useful in gerontological studies. A concise comparison of quantitative and qualitative methods is made, and suggestions are provided for when qualitative approaches are useful. A review of the three most common approaches is provided. Most important, references are provided for those gerontologists interested in learning more about qualitative research methods.     

Herbivory,plant resistance,and climate in the tree ring record: interactions distort climatic reconstructions

To understand climate change, dendrochronologists have used tree ring analyses to reconstruct past climates, as well as ecological processes such as herbivore population dynamics. Such reconstructions, however, have been hindered by a lack of experiments that separate the influences of confounding impacts on tree rings, such as herbivores and the interactions of multiple factors. Our long-term experiments with scale insects on resistant and susceptible pines demonstrate three major points that are important to the application of this commonly used tool. (i) Herbivory reduced tree ring growth by 25-35%. (ii) The impact on ring growth distorted climate reconstruction, resulting in the overestimation of past moisture levels by more than 2-fold. Our data suggest that, if distortion because of herbivory has been a problem in previous reconstructions, estimates of the magnitude of recent climate changes are likely to be conservative. (iii) Our studies support a detectible plant resistance x herbivore x climate interaction in the tree ring record. Because resistance and susceptibility to herbivory are known to be genetically based in many systems, the potential exists to incorporate plant genetics into the field of dendrochronology, where it may be used to screen distortions from the tree ring record.     

Changing incidence of out-of-hospital ventricular fibrillation, 1980-2000

Context  Recent reports from 2 European cities and an earlier observation from Seattle, Wash, suggest that the number of patients treated for out-of-hospital ventricular fibrillation (VF) has declined. Objective  To analyze the incidence of cardiac arrest and to examine relationships among incidence, sex, race, age, and first identified cardiac rhythm in Seattle. Design, Setting, and Patients  Population-based study of all cardiac arrest cases with presumed cardiac etiology who received advanced life support from Seattle Fire Department emergency medical services during specified periods between 1979 and 2000. United States Census data for Seattle in 1980, 1990, and 2000 were used to determine incidence rates for treated cardiac arrest with adjustments for age and sex. Main Outcome Measures  Changes in incidence of cardiac arrest and initial recorded cardiac rhythm. Results  The adjusted annual incidence of cardiac arrest with VF as the first identified rhythm decreased by about 56% from 1980 to 2000 (from 0.85 to 0.38 per 1000; relative risk [RR], 0.44; 95% confidence interval [CI], 0.37-0.53). Similar reductions occurred in blacks (54%; RR, 0.45; 95% CI, 0.26-0.79) and whites (53%; RR, 0.47; 95% CI, 0.38-0.58) and was most evident in men (57%; RR, 0.43; 95% CI, 0.35-0.53), in whom the baseline incidence was relatively high. When all treated arrests with presumed cardiac etiology were considered, that incidence decreased by 43% (RR, 0.58; 95% CI, 0.49-0.67) in men but negligibly in women, for whom a relatively low incidence of VF also declined but was offset by more cases with asystole or pulseless electrical activity. Conclusion  We observed a major decline in the incidence of out-of-hospital VF and in all cases of treated cardiac arrest presumably due to heart disease in Seattle. These changes likely reflect the national decline in coronary heart disease mortality.      

Effects of hormone replacement therapy and antioxidant vitamin supplements on coronary atherosclerosis in postmenopausal women: a randomized controlled trial

Context  Hormone replacement therapy (HRT) and antioxidant vitamins are widely used for secondary prevention in postmenopausal women with coronary disease, but no clinical trials have demonstrated benefit to support their use. Objective  To determine whether HRT or antioxidant vitamin supplements, alone or in combination, influence the progression of coronary artery disease in postmenopausal women, as measured by serial quantitative coronary angiography. Design, Setting, and Patients  The Women's Angiographic Vitamin and Estrogen (WAVE) Trial, a randomized, double-blind trial of 423 postmenopausal women with at least one 15% to 75% coronary stenosis at baseline coronary angiography. The trial was conducted from July 1997 to January 2002 in 7 clinical centers in the United States and Canada. Interventions  Patients were randomly assigned in a 2 x 2 factorial design to receive either 0.625 mg/d of conjugated equine estrogen (plus 2.5 mg/d of medroxyprogesterone acetate for women who had not had a hysterectomy), or matching placebo, and 400 IU of vitamin E twice daily plus 500 mg of vitamin C twice daily, or placebo. Main Outcome Measure  Annualized mean (SD) change in minimum lumen diameter (MLD) from baseline to concluding angiogram of all qualifying coronary lesions averaged for each patient. Patients with intercurrent death or myocardial infarction (MI) were imputed the worst rank of angiographic outcome. Results  The mean (SD) interval between angiograms was 2.8 (0.9) years. Coronary progression, measured in mean (SD) change, worsened with HRT by 0.047 (0.15) mm/y and by 0.024 (0.15) mm/y with HRT placebo (P = .17); and for antioxidant vitamins by 0.044 (0.15) mm/y and with vitamin placebo by 0.028 (0.15) mm/y (P = .32). When patients with intercurrent death or MI were included, the primary outcome showed an increased risk for women in the active HRT group (P = .045), and suggested an increased risk in the active vitamin group (P = .09). Fourteen patients died in the HRT group and 8 in the HRT placebo group (hazard ratio [HR], 1.8; 95% confidence interval [CI], 0.75-4.3), and 16 in the vitamin group and 6 in the vitamin placebo group (HR, 2.8; 95% CI, 1.1-7.2). Death, nonfatal MI, or stroke occurred in 26 HRT patients vs 15 HRT controls (HR, 1.9; 95% CI, 0.97-3.6) and in 26 vitamin patients and 18 vitamin controls (HR, 1.5; 95% CI, 0.80-2.9). There was no interaction between the 2 treatment interventions. Conclusion  In postmenopausal women with coronary disease, neither HRT nor antioxidant vitamin supplements provide cardiovascular benefit. Instead, a potential for harm was suggested with each treatment.