Measure Of Reserve Research Articles

Development and Validation of a New Adenosine-Independent Index of Stenosis Severity From Coronary Wave–Intensity Analysis: Results of the ADVISE (ADenosine Vasodilator Independent Stenosis Evaluation) Study

The purpose of this study was to develop an adenosine-independent, pressure-derived index of coronary stenosis severity. Assessment of stenosis severity with fractional flow reserve (FFR) requires that coronary resistance is stable and minimized. This is usually achieved by administration of pharmacological agents such as adenosine. In this 2-part study, we determine whether there is a time when resistance is naturally minimized at rest and assess the diagnostic efficiency, compared with FFR, of a new pressure-derived adenosine-free index of stenosis severity over that time. A total of 157 stenoses were assessed. In part 1 (39 stenoses), intracoronary pressure and flow velocity were measured distal to the stenosis; in part 2 (118 stenoses), intracoronary pressure alone was measured. Measurements were made at baseline and under pharmacologic vasodilation with adenosine. Wave-intensity analysis identified a wave-free period in which intracoronary resistance at rest is similar in variability and magnitude (coefficient of variation: 0.08 ± 0.06 and 284 ± 147 mm Hg s/m) to those during FFR (coefficient of variation: 0.08 ± 0.06 and 302 ± 315 mm Hg s/m; p = NS for both). The resting distal-to-proximal pressure ratio during this period, the instantaneous wave-free ratio (iFR), correlated closely with FFR (r = 0.9, p < 0.001) with excellent diagnostic efficiency (receiver-operating characteristic area under the curve of 93%, at FFR <0.8), specificity, sensitivity, negative and positive predictive values of 91%, 85%, 85%, and 91%, respectively. Intracoronary resistance is naturally constant and minimized during the wave-free period. The instantaneous wave-free ratio calculated over this period produces a drug-free index of stenosis severity comparable to FFR. (Vasodilator Free Measure of Fractional Flow Reserve [ADVISE]; NCT01118481).

Impact of cancer therapies on ovarian reserve

To determine whether measures of ovarian reserve differ between females exposed to cancer therapies in a dose-dependent manner as compared with healthy controls of similar age and late reproductive age. Cross-sectional analysis of data from a prospective cohort study. University medical center. Seventy-one cancer survivors aged 15-39 years; 67 healthy, similarly aged unexposed subjects; and 69 regularly menstruating women of late reproductive age (40-52 years). None. Early follicular-phase hormones (FSH, E(2), inhibin B, antimüllerian hormone [AMH]) and ovarian ultrasound measurements (ovarian volume and antral follicle counts [AFC]) were compared using multivariable linear regression. In adjusted models, FSH, AMH, and AFC differed between exposed vs. unexposed subjects (FSH 11.12 mIU/mL vs. 7.25 mIU/mL; AMH 0.81 ng/mL vs. 2.85 ng/mL; AFC 14.55 vs. 27.20). In participants with an FSH <10 mIU/mL, survivors had lower levels of AMH and AFC compared with controls. Alkylating agent dose score was associated with increased levels of FSH and decreased levels of AMH. Exposure to pelvic radiation was associated with impairment in FSH, AMH, AFC, and ovarian volume. Antimüllerian hormone was similar in women previously exposed to high-dose cancer therapy and 40-42-year-old controls. Measures of ovarian reserve are impaired in a dose-dependent manner among cancer survivors compared with unexposed females of similar age. Reproductive hormone levels in menstruating survivors exposed to high-dose therapy are similar to those in late-reproductive-age women. The predictive value of measures for pregnancy and menopause must be studied. CLINICALTRIALS.GOV IDENTIFIER: NCT01143844.

Reserve, Brain Changes, and Decline

Reserve refers to the brain's ability to cope with increasing damage. There is no direct measure of reserve, but it is commonly reflected in the literature by proxies such as brain volume, head size, education, occupation, socioeconomic status, and mental and physical engagement. This article provides an overview of the concepts and applications being used to explore reserve, and discusses how these empiric proxies of reserve, their hypothesized biological mechanisms, and the apparent protection from age-related disease are connected.

Primary Results of ADVISE: Validation of a Vasodilator Independent Measure of Coronary Fractional Flow Reserve

This article discuesses the results of the ADVISE trial, which evaluated instantaneous wave-free ratio, a new technology that assesses coronary stenosis using pressure as a surrogate for coronary flow during a period of naturally occurring stable resistance, thereby avoiding the need for adenosine or other vasodilators.

Improved Cardiac Risk Assessment With Noninvasive Measures of Coronary Flow Reserve

Impaired vasodilator function is an early manifestation of coronary artery disease and may precede angiographic stenosis. It is unknown whether noninvasive assessment of coronary vasodilator function in patients with suspected or known coronary artery disease carries incremental prognostic significance. A total of 2783 consecutive patients referred for rest/stress positron emission tomography were followed up for a median of 1.4 years (interquartile range, 0.7-3.2 years). The extent and severity of perfusion abnormalities were quantified by visual evaluation of myocardial perfusion images. Rest and stress myocardial blood flows were calculated with factor analysis and a 2-compartment kinetic model and were used to compute coronary flow reserve (coronary flow reserve equals stress divided by rest myocardial blood flow). The primary end point was cardiac death. Overall 3-year cardiac mortality was 8.0%. The lowest tertile of coronary flow reserve (<1.5) was associated with a 5.6-fold increase in the risk of cardiac death (95% confidence interval, 2.5-12.4; P<0.0001) compared with the highest tertile. Incorporation of coronary flow reserve into cardiac death risk assessment models resulted in an increase in the c index from 0.82 (95% confidence interval, 0.78-0.86) to 0.84 (95% confidence interval, 0.80-0.87; P=0.02) and in a net reclassification improvement of 0.098 (95% confidence interval, 0.025-0.180). Addition of coronary flow reserve resulted in correct reclassification of 34.8% of intermediate-risk patients (net reclassification improvement=0.487; 95% confidence interval, 0.262-0.731). Corresponding improvements in risk assessment for mortality from any cause were also demonstrated. Noninvasive quantitative assessment of coronary vasodilator function with positron emission tomography is a powerful, independent predictor of cardiac mortality in patients with known or suspected coronary artery disease and provides meaningful incremental risk stratification over clinical and gated myocardial perfusion imaging variables.

Editorial commentary: What's in a number? The polycystic ovary revisited

Editorial commentary: What's in a number? The polycystic ovary revisited

P75 Impaired cardiorespiratory reserve in primary biliary cirrhosis patients undergoing liver transplant assessment

IntroductionIt has been previously shown that PBC patients have bioenergetic abnormality in both peripheral and cardiac muscle. In particular they exhibit significantly lower cardiac muscle phosphocreatine-to-ATP ratio (measure of cardiac...

The association of urinary phthalate monoester concentrations with measures of ovarian reserve among patients undergoing fertility treatments

To determine the association of urinary phthalate metabolite concentrations with measures of ovarian reserve. Prospective cohort, 201 women undergoing fertility treatment. Urinary concentrations of 7 phthalate (P) metabolites [mono(2-ethylhexyl)-P (MEHP), monobutyl-P (MBP), monoethyl-P (MEP), monobenzyl-P (MBzP), mono(2-ethyl-5-hydroxyhexyl)-P (MEHHP), mono(2-ethyl-5-oxohexyl)-P (MEOHP), and mono(2-ethyl-5-carboxypentyl)-P (MECPP)] were measured using solid-phase extraction, high performance liquid chromatography, isotope dilution tandem mass spectrometry. Transvaginal ultrasonography was used to determine the ovarian volume and antral follicle count (AFC). Day-3 FSH was measured in the serum. Poisson, linear, and logistic regression were used to evaluate the association of urinary specific-gravity (SG) adjusted phthalate concentrations with measures of ovarian reserve, adjusted for age. SG-MEHP was negatively associated with the number of follicles (p-trend: 0.03), with an average decrease of 21% (95%CI:−37%,−2%; P=0.03) and 19% (95%CI:−34%,−1%; P=0.04) in the number of follicles for the highest and middle tertiles of SG-MEHP, respectively, compared to the lowest one. SG-MEOHP and SG-MEP were also negatively associated with the number of follicles (p-trend: 0.1). The middle and highest tertiles of SG-MEHP were associated with an increased odds of an AFC<15 (OR: 3.2, 95%CI:1.2-8.6, and OR: 4.2, CI:1.5-12.4, respectively). Similarly, the highest tertile of SG-MEOHP was associated with an increased odds of AFC<15 (OR: 13.1, 95%CI:1.1-8.8). Phthalate metabolites were detected in urine from >70% of participating women. There was a trend of lower AFC with higher levels of phthalates (mainly DEHP metabolites). Based on animal data showing that some phthalates are endocrine disruptors through altered endogenous steroid hormone signaling, there is potential concern in humans of an accelerated follicle loss and reproductive aging.

The association of urinary paraben concentrations with measures of ovarian reserve among patients from a fertility center

Investigate the relationship of urinary paraben concentrations with measures of ovarian reserve. Parabens are preservatives with widespread exposure among the US population and in experimental studies are weakly estrogenic.

Repetitive ovarian reserve testing as a measure of natural fecundability

Early follicular phase, urinary follicle stimulating hormone (FSH) is used as a measure of ovarian reserve and considered a potential fertility test. We sought to determine the value of repetitive urinary FSH testing in the prediction of natural fecundability.

Antral follicle counts are strongly associated with live-birth rates after assisted reproduction, with superior treatment outcome in women with polycystic ovaries

To evaluate the association of antral follicle count (AFC) with invitro fertilization/intracytoplasmic sperm injection (IVF-ICSI) outcome in a large unselected cohort of patients covering the entire range of AFC. Prospective observational study. University-affiliated private infertility center. 2,092 women undergoing 4,308 IVF-ICSI cycles. AFC analyzed for associations with treatment outcome and statistically adjusted for repeated treatments and age. Pregnancy rate, live-birth rate, and stimulation outcome parameters. The AFC was log-normally distributed. Pregnancy rates and live-birth rates were positively associated with AFC in a log-linear way, leveling out above AFC ∼30. Treatment outcome was superior among women with polycystic ovaries, independent from ovulatory status. The findings were significant also after adjustment for age and number of oocytes retrieved. Pregnancy and live-birth rates are log-linearly related to AFC. Polycystic ovaries, most often excluded from studies on ovarian reserve, fit as one extreme in the spectrum of AFC; a low count constitutes the other extreme, with the lowest ovarian reserve and poor treatment outcome. The findings remained statistically significant also after adjustment for the number of oocytes retrieved, suggesting this measure of ovarian reserve comprises information on oocyte quality and not only quantity.

A Life Course Model of Cognitive Activities, Socioeconomic Status, Education, Reading Ability, and Cognition

To cross-sectionally quantify the contribution of proxy measures of cognitive reserve reflective of the lifespan, such as education, socioeconomic status (SES), reading ability, and cognitive activities, in explaining late-life cognition. Prospective observational cohort study of aging. Retirement communities across the Chicago metropolitan area. Nine hundred fifty-one older adults free of clinical dementia in the Rush Memory and Aging Project (aged 79 ± 8, 74% female). Baseline data on multiple life course factors included early-, mid-, and late-life participation in cognitive activities; early-life and adult SES; education; and reading ability (National Adult Reading Test; NART). Path analysis quantified direct and indirect standardized effects of life course factors on global cognition and five cognitive domains (episodic memory, semantic memory, working memory, visuospatial ability, perceptual speed). Adjusting for age, sex, and race, education had the strongest association with global cognition, episodic memory, semantic memory, and visuospatial ability, whereas NART (followed by education) had the strongest association with working memory. Late-life cognitive activities had the strongest association with perceptual speed, followed by education. These cross-sectional findings suggest that education and reading ability are the most-robust proxy measures of cognitive reserve in relation to late-life cognition. Additional research leveraging path analysis is warranted to better understand how these life course factors, reflecting the latent construct of cognitive reserve, affect abnormal cognitive aging.

Corrected Cerebral Flow Reserve from Brain SPECT as a Marker of Dementia Risk

Background: Mixed Dementia (including Alzheimer’s) risk may be increased by hypertension (BP), diabetes mellitus (DM), waist-height ratio (WH), traumatic brain injury (TI), thyroid (Td), renal (Rd), pituitary (Pd) disease and depression (De). To study dementia pathogenesis we developed a brain SPECT measure of cerebral flow reserve (CFi) with correction factors due to decreased tracer clearance in Rd.

Does cognitive reserve shape cognitive decline?

Cognitive reserve is associated with a lower risk of dementia, but the extent to which it shapes cognitive aging trajectories remains unclear. Our objective is to examine the impact of 3 markers of reserve from different points in the life course on cognitive function and decline in late adulthood. Data are from 5,234 men and 2,220 women, mean age 56 years (standard deviation = 6) at baseline, from the Whitehall II cohort study. Memory, reasoning, vocabulary, and phonemic and semantic fluency were assessed 3× over 10 years. Linear mixed models were used to assess the association between markers of reserve (height, education, and occupation) and cognitive decline, using the 5 cognitive tests and a global cognitive score composed of these tests. All 3 reserve measures were associated with baseline cognitive function; the strongest associations were with occupation and the weakest with height. All cognitive functions except vocabulary declined over the 10-year follow-up period. On the global cognitive test, there was greater decline in the high occupation group (-0.27; 95% confidence interval [CI], -0.28 to -0.26) compared to the intermediate (-0.23; 95% CI, -0.25 to -0.22) and low groups (-0.21; 95% CI, -0.24 to -0.19); p = 0.001. The decline in reserve groups defined by education (p = 0.82) and height (p = 0.55) was similar. Cognitive performance over the adult life course was remarkably higher in the high reserve groups. However, rate of cognitive decline did not differ between reserve groups with the exception of occupation, where there was some evidence of greater decline in the high occupation group.

Hypercholesterolemia-induced oxidative stress in heart and its prevention by vitamin E

Oxygen-free radicals have been implicated in hypercholesteolemic atherosclerosis. It is possible that hypercholesterolemia produces oxidative stress in myocardium. We therefore investigated the effects of a high cholesterol diet in the absence or presence of vitamin E on serum cholesterol and lipid peroxidation product malondialdehyde (MDA), chemiluminescence (M-CL), a measure of antioxidant reserve, and activity of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px)] in cardiac muscles of rabbits. Rabbits were divided into four groups: Group I, regular rabbit chow diet; Group II, same as Group I + vitamin E; Group III, high cholesterol diet; Group IV, high cholesterol + vitamin E. The heart was removed under anesthesia at the end of 4 months on their respective diets for various biochemical measurements. Serum cholesterol in Groups III and IV increased to a similar extent. There was an increase in the levels of MDA, M-CL, GSH-Px activity and a decrease in SOD activity in hypercholesterolemic rabbits in the absence of vitamin E. Vitamin E prevented the hypercholesterolemia-induced changes in cardiac MDA, M-CL, and GSH-Px. These results suggest that hypercholesterolemia produces oxidative stress in the myocardium which may be due to a decrease in the antioxidant reserve, and that vitamin E is effective in preventing hypercholesterolemia-induced oxidative stress on the myocardium.

Conceptual and Measurement Challenges in Research on Cognitive Reserve

Cognitive reserve, broadly conceived, encompasses aspects of brain structure and function that optimize individual performance in the presence of injury or pathology. Reserve is defined as a feature of brain structure and/or function that modifies the relationship between injury or pathology and performance on neuropsychological tasks or clinical outcomes. Reserve is challenging to study for two reasons. The first is: reserve is a hypothetical construct, and direct measures of reserve are not available. Proxy variables and latent variable models are used to attempt to operationalize reserve. The second is: in vivo measures of neuronal pathology are not widely available. It is challenging to develop and test models involving a risk factor (injury or pathology), a moderator (reserve) and an outcome (performance or clinical status) when neither the risk factor nor the moderator are measured directly. We discuss approaches for quantifying reserve with latent variable models, with emphasis on their application in the analysis of data from observational studies. Increasingly latent variable models are used to generate composites of cognitive reserve based on multiple proxies. We review the theoretical and ontological status of latent variable modeling approaches to cognitive reserve, and suggest research strategies for advancing the field.

Antimüllerian hormone as a predictor of controlled ovarian hyperstimulation outcome: comparison of two commercial immunoassay kits

This study was performed to compare antimüllerian hormone (AMH) levels measured by two commercially available AMH measuring kits currently available, and to evaluate the AMH levels as predictor of controlled ovarian hyperstimulation (COH) outcome using the two different kits. The two assays for AMH measurement provide similar results, and serum AMH levels measured by the two kits both could be used as COH outcome predictors with similar reference values.

Der chronische Schmerzpatient als Notfall - Nicht algesiologische Akutsituationen: Obstipation, Übelkeit und Erbrechen

Constipation, nausea and sickness are frequent accessory symptoms in patients suffering from chronic pain. Typical causes are the underlying disease and the medical treatment against chronic pain. Most often opioid treatment induces an enteric dysfunction syndrome with constipation as a leading symptom and, especially in the initial phase, nausea due to direct stimulation of central structures. Therefore prophylactic and therapeutic strategies should be determined routinely and additionally, in special cases, different reserve measures might be applied.

Association of plasma beta-amyloid level and cognitive reserve with subsequent cognitive decline.

Lower plasma β-amyloid 42 and 42/40 levels have been associated with incident dementia, but results are conflicting and few have investigated cognitive decline among elders without dementia. To determine if plasma β-amyloid is associated with cognitive decline and if this association is modified by measures of cognitive reserve. We studied 997 black and white community-dwelling older adults from Memphis, Tennessee, and Pittsburgh, Pennsylvania, who were enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998 with 10-year follow-up in 2006-2007. Participant mean age was 74.0 (SD, 3.0) years; 55.2% (n = 550) were female; and 54.0% (n = 538) were black. Association of near-baseline plasma β-amyloid levels (42 and 42/40 measured in 2010) and repeatedly measured Modified Mini-Mental State Examination (3MS) results. Low β-amyloid 42/40 level was associated with greater 9-year 3MS cognitive decline (lowest β-amyloid tertile: mean change in 3MS score, -6.59 [95% confidence interval [CI], -5.21 to -7.67] points; middle tertile: -6.16 [95% CI, -4.92 to -7.32] points; and highest tertile: -3.60 [95% CI, -2.27 to -4.73] points; P < .001). Results were similar after multivariate adjustment for age, race, education, diabetes, smoking, and apolipoprotein E [APOE ] e4 status and after excluding the 72 participants with incident dementia. Measures of cognitive reserve modified this association whereby among those with high reserve (at least a high school diploma, higher than sixth-grade literacy, or no APOE e4 allele), β-amyloid 42/40 was less associated with multivariate adjusted 9-year decline. For example, among participants with less than a high school diploma, the 3MS score decline was -8.94 (95% CI, -6.94 to -10.94) for the lowest tertile compared with -4.45 (95% CI, -2.31 to -6.59) for the highest tertile, but for those with at least a high school diploma, 3MS score decline was -4.60 (95% CI,-3.07 to -6.13) for the lowest tertile and -2.88 (95% CI,-1.41 to -4.35) for the highest tertile (P = .004 for interaction). Interactions were also observed for literacy (P = .005) and for APOE e4 allele (P = .02). Lower plasma β-amyloid 42/40 is associated with greater cognitive decline among elderly persons without dementia over 9 years, and this association is stronger among those with low measures of cognitive reserve.

Menopausal symptoms and fertility concerns in premenopausal breast cancer survivors

Many young breast cancer survivors experience menopausal symptoms and feel concerned about infertility due to oncologic treatment. However, there has been little research to date comparing young survivors’ concerns and symptoms with those of young women of the same age and gravidity in the general population. We surveyed breast cancer survivors with regular menses after adjuvant chemotherapy and compared them with age-matched, gravidity-matched controls as part of a study to evaluate the effects of chemotherapy on ovarian reserve. All survivors were 1 year or more from diagnosis of early-stage breast cancer, without evidence of recurrence. The survey assessed menopausal symptoms and infertility concerns. The study was stopped after a planned interim analysis of the first 20 matched pairs revealed significantly diminished measures of ovarian reserve in survivors compared with controls. Mean age was 37 years for both groups(range, 31-43 y). Eighty percent of survivors and 25% of controls expressed some concern regarding fertility at the time of the survey (P = 0.001). Survivors were more likely to report bothersome menopausal symptoms than were controls (P = 0.05). An exploratory analysis revealed that menopausal symptoms were greatest in the survivor staking tamoxifen. Young women who remained premenopausal after breast cancer chemotherapy expressed greater concern about fertility and reported more menopausal symptoms than did age- and gravidity-matched controls. This may have been due to cancer diagnosis or treatment, or it may reflect other differences between the survivors and controls in this study. Additional research is warranted to determine how to most effectively address fertility concerns and reduce symptom burden in this population.