Multi-response Mendelian randomization: Identification of shared and distinct exposures for multimorbidity and multiple related disease outcomes

The existing framework of Mendelian randomization (MR) infers the causal effect of one or multiple exposures on one single outcome. It is not designed to jointly model multiple outcomes, as would be necessary to detect causes of more than one outcome and would be relevant to model multimorbidity or other related disease outcomes. Here, we introduce multi-response Mendelian randomization (MR2), an MR method specifically designed for multiple outcomes to identify exposures that cause more than one outcome or, conversely, exposures that exert their effect on distinct responses. MR2 uses a sparse Bayesian Gaussian copula regression framework to detect causal effects while estimating the residual correlation between summary-level outcomes, i.e., the correlation that cannot be explained by the exposures, and vice versa. We show both theoretically and in a comprehensive simulation study how unmeasured shared pleiotropy induces residual correlation between outcomes irrespective of sample overlap. We also reveal how non-genetic factors that affect more than one outcome contribute to their correlation. We demonstrate that by accounting for residual correlation, MR2 has higher power to detect shared exposures causing more than one outcome. It also provides more accurate causal effect estimates than existing methods that ignore the dependence between related responses. Finally, we illustrate how MR2 detects shared and distinct causal exposures for five cardiovascular diseases in two applications considering cardiometabolic and lipidomic exposures and uncovers residual correlation between summary-level outcomes reflecting known relationships between cardiovascular diseases.

Pulse transient hot strip technique adapted for slab sample geometry to study anisotropic thermal transport properties of μm-thin crystalline films

A new method based on the adaptation of the Pulse Transient Hot Strip technique to slab sample geometry has been developed for studying thermal conductivity and thermal diffusivity of anisotropic thin film materials (<50 μm) with thermal conductivity in the 0.01-100 W/mK range, deposited on thin substrates (i.e., wafers). Strength of this technique is that it provides a well-controlled thermal probing depth, making it possible to probe a predetermined depth of the sample layer and thereby avoiding the influence from material(s) deeper down in the sample. To verify the technique a series of measurements were conducted on a y-cut single crystal quartz wafer. A Hot Strip sensor (32-μm wide, 3.2-mm long) was deposited along two orthogonal crystallographic (x- and z-) directions and two independent pulse transients were recorded. Thereafter, the data was fitted to our theoretical model, and the anisotropic thermal transport properties were determined. Using a thermal probing depth of only 30 μm, we obtained a thermal conductivity along the perpendicular (parallel) direction to the z-, i.e., optic axis of 6.48 (11.4) W/mK, and a thermal diffusivity of 3.62 (6.52) mm(2)/s. This yields a volumetric specific heat of 1.79 MJ/mK. These values agree well with tabulated data on bulk crystalline quartz supporting the accuracy of the technique, and the obtained standard deviation of less than 2.7% demonstrates the precision of this new measurement technique.

3-year study of donepezil therapy in Alzheimer's disease: effects of early and continuous therapy

Delays in the diagnosis of Alzheimer's disease, and, therefore, delays in treatment, may have a detrimental effect on a patient's long-term well-being. This study assessed the effects of postponing donepezil treatment for 1 year by comparing patients treated continuously for 3 years with those who received placebo for 1 year followed by open-label donepezil for 2 years. Patients (n = 286) with possible or probable Alzheimer's disease (according to DSM-IV, NINCDS-ADRDA, and Mini-Mental State Examination criteria; see text) were randomized to receive donepezil (5 mg/day for 4 weeks, 10 mg/day thereafter) or placebo (delayed-start group) for 1 year. Of the 192 completers, 157 began a 2-year, open-label phase of donepezil treatment. Outcome measures were the Gottfries-Bråne-Steen scale, the Mini-Mental State Examination, the Global Deterioration Scale, the Progressive Deterioration Scale, the Neuropsychiatric Inventory, and safety (adverse events). Mixed regression analysis was used to compare changes between the groups over 3 years on the efficacy measures. There was a trend for patients receiving continuous therapy to have less global deterioration (Gottfries-Bråne-Steen scale) than those who had delayed treatment (p = 0.056). Small but statistically significant differences between the groups were observed for the secondary measures of cognitive function (Mini-Mental State Examination; p = 0.004) and cognitive and functional abilities (Global Deterioration Scale; p = 0.0231) in favor of continuous donepezil therapy. Over 90% of the patients in both cohorts experienced one treatment-emergent adverse event; most were considered mild or moderate. In conclusion, patients in whom the start of treatment is delayed may demonstrate slightly reduced benefits as compared with those seen in patients starting donepezil therapy early in the course of Alzheimer's disease. These data support the long-term efficacy and safety of donepezil.

A 1-year, randomized, placebo-controlled study of donepezil in patients with mild to moderate AD

OBJECTIVE

To evaluate the long-term clinical efficacy and safety of donepezil versus placebo over 1 year in patients with mild to moderate AD.

METHODS

Patients (n = 286; mean age, 72.5 years) with possible or probable AD from five Northern European countries were randomized to receive either donepezil (n = 142; 5 mg/day for 28 days, followed by 10 mg/day) or placebo (n = 144) for 1 year.

RESULTS

The study was completed by 66.9% of the donepezil- and 67.4% of the placebo-treated patients. The benefit of donepezil over placebo was demonstrated by the Gottfries-Bråne-Steen (a global assessment for rating dementia symptoms) total score at weeks 24, 36, and 52 (p < 0.05) and at the study end point (week 52, last observation carried forward; p = 0.054). Advantages of donepezil over placebo were also observed in cognition and activities of daily living (ADL) assessed by the Mini-Mental State Examination at weeks 24, 36, and 52, and the end point (p < 0.02) and by the Progressive Deterioration Scale at week 52 and the end point (p < 0.05). Adverse events (AE) were recorded for 81.7% of donepezil- and 75.7% of placebo-treated patients, with 7% of donepezil- and 6.3% of placebo-treated patients discontinuing because of AE. Treatment response to donepezil was not predicted by APOE genotype or sex in this population.

CONCLUSION

As the first 1-year, multinational, double-blinded, placebo-controlled study of a cholinesterase inhibitor in AD, these data support donepezil as a well tolerated and effective long-term treatment for patients with AD, with benefits over placebo on global assessment, cognition, and ADL.

Strengthening of tooth enamel by a remineralizing toothpaste after exposure to an acidic soft drink

The effect of remineralizing and conventional toothpaste treatments on the hardness of intact and acid soft drink-etched enamel were assessed in a laboratory study. The remineralizing toothpaste (Enamelon Toothpaste) used in the study contains NaF, and simultaneously provides dissolved calcium, phosphate and fluoride ions. The conventional toothpaste contains NaF in a silica base. Sound extracted maxillary human incisors, mounted in epoxy resin with the facial incisal two-thirds exposed, were polished with 0.3 mu alumina. Groups of ten teeth were exposed to either twenty 5-minute treatments with an acid soft drink (pH 2.4), remineralizing or conventional fluoride toothpaste, or to twenty alternating cycles of a 5-minute protective treatment with either the remineralizing or conventional toothpastes, followed by 5-minute exposures to the acid soft drink, or to 20 five-minute exposures to the acid soft drink followed by 20 five-minute restorative treatments with the remineralizing or conventional toothpastes. Knoop Hardness measurements were made before and after treatment using a 500 g load and 15-second dwell time. Acid soft drink exposure produced a 15.4% drop in hardness compared with 4.9% and 1.6% hardness increases due to treatments of intact enamel with the remineralizing and conventional toothpastes, respectively. Protective treatments using the remineralizing and conventional toothpastes significantly reduced the drop in hardness due to acid soft drink exposure to 3.3% and 6.2%, respectively. Restorative treatments by the remineralizing and conventional toothpastes significantly increased the hardness of the acid soft drink-weakened enamel by 12.1% and 7.3%, respectively. Both toothpastes were effective in inhibiting damage due to acid soft drink exposure, but the remineralizing toothpaste was more effective in hardening intact and decalcified enamel than the conventional toothpaste (p < 0.05).

The accuracy of the dorsoproximal-dorsodistal projection in assessing third carpal bone sclerosis in standardbred trotters

Thirty-five carpal joints from 20 standardbred trotters, age 1 to 7 years, all euthanized for nonorthopedic reasons, were examined to investigate the correlation between assessments of subchondral bone sclerosis in the third carpal bone from radiographs in the dorsoproximal-dorsodistal (DPr-DDi) projection and histomorphometric bone volume density measurements. The agreement between assessments of sclerosis from antemortem versus postmortem radiographs was also evaluated. Bones graded as sclerotic in the DPr-DDi projection had significantly higher bone volume density values for all areas of measurement than nonsclerotic bones. For sclerotic bones, grading of sclerosis was significantly associated with volume density measurements in the central cancellous bone only. There was a good agreement (Kw = 0.71) between assessments of radiographic bone sclerosis from antemortem versus postmortem radiographs.

A multicentre (double-blind) comparative study to assess the safety and efficacy of fluconazole and griseofulvin in the treatment of tinea corporis and tinea cruris

In a double-blind, parallel group study we compared fluconazole 150 mg once weekly with griseofulvin 500 mg once daily for 4-6 weeks in the treatment of tinea corporis or tinea cruris. Eighty-four of 114 patients (74%) (39% after 3 weeks) were clinically cured in the fluconazole group compared with 72 of 116 (62%) (39% after 3 weeks) in the griseofulvin group (P = 0.06). In the fluconazole group 78% were mycological cured compared with 80% in the griseofulvin group. In the fluconazole group nine patients (7.5%) had treatment related adverse events and in the griseofulvin group 15 patients (12.5%) had adverse events. Fluconazole 150 mg once weekly for 6 weeks is both clinically and mycologically effective in the treatment of tinea corporis and tinea cruris and few side-effects were reported.

Ultrastructure of the secretory endometrium during oestrus in young maiden and foaled mares

Cyclical accumulation of uterine fluid occurs during oestrus and is often seen in excessive volumes in mares considered susceptible to endometritis. Since the mechanisms behind the formation of free uterine fluid remain to be clarified, the fine structure of the secretory equine endometrium was studied in biopsies collect during videoendoscopy from 14 endometritis-free, 4-9-year-old mares during oestrus. A distinct oedema of the tunica mucosa was evident. The surface epithelium had both ciliated and nonciliated cells and, particularly at the uterine body, often presented intra-epithelial macrophages. The epithelial cells of the gland duct were similar to the surface epithelium, except that the nonciliated cells lacked secretory vesicles in the non ciliated cells. This glandular epithelium presented clear signs of secretory activity with conspicuous secretory vesicles holding electron-dense granula in the adluminal cytoplasm and a well developed supranuclear Golgi apparatus. Secretory products as well as cell debris were commonly found in the lumen of the glands. No clear signs of apocrine secretion were found and it seemed therefore, that the mechanism of secretion is merocrine, i.e. by exocytosis. The endometrial oedema and intense secretory activity, both under oestrogenic influence, contribute to the building up of the uterine fluid during oestrus. No differences in morphology of the secretory endometrium could be noticed between nulliparous mares and mares that had had 1 or 2 foals.

Effects of maternal diabetes or in vitro hyperglycemia on uptake of palmitic and arachidonic acid by rat embryos

Altered transfer of nutrients from mother to conceptus may be involved in the pathogenesis of the developmental disturbances in offspring of diabetic mothers. In our study, the embryonic uptake of a saturated (palmitic acid) and a nonsaturated (arachidonic acid) fatty acid was evaluated in a normal and a diabetes-like environment under in vivo and in vitro conditions that yield growth retardation and somatic malformations in the embryos. The palmitic acid uptake in embryos from diabetic rats and in embryos cultured in vitro in 30 mmol/L D-glucose did not differ from the respective controls. Only embryos cultured in the highest D-glucose concentration (60 mmol/L) showed slightly increased uptake, which suggests that alterations in palmitic acid transfer have no role in the processes of embryonic maldevelopment in diabetic pregnancy. In contrast, the results showed that a diabetes-like environment both in vivo and in vitro causes increased embryonic uptake of arachidonic acid. Consequently, if the teratogenic mechanisms of diabetic pregnancy involve decreased embryonic levels of arachidonic acid, as has been suggested, this would not be the effect of a decreased uptake per se, but rather of an altered intracellular metabolism or decreased extracellular availability of this fatty acid.

Treatment of candidal vaginitis. A prospective randomized investigator-blind multicenter study comparing topically applied econazole with oral fluconazole

Two hundred and thirty-five women with clinically and microbiologically proven candidal vaginitis were randomly allocated for treatment with either one topically applied vaginal tablet of 150 mg econazole (114 women) or one orally administered capsule of 150 mg fluconazole (121 women). The women returned for follow-up visits 7-10, 28-35, and 80-100 days after the recruitment visit. Women with clinical and/or mycological failures and/or a recurrence were successively excluded from the follow-up. At the 28-35-day follow-up visit, the women treated with fluconazole had a significantly higher clinical/microbiological cure rate than those given econazole (P = 0.022; Fisher's exact 2-tail test). No significant such differences were observed at the 7-10 and the 80-100-day follow-up visits, although fluconazole tended to be more efficacious. Nine women administered fluconazole, and 2 women given econazole reported minor systemic side effects of the treatment. Three women out of 4 preferred oral to local therapy of candidal vaginitis.