Daytime Sleepiness Is Associated with Lower Cognitive Scores: The Look AHEAD Study

Background

Daytime sleepiness is common in older adults and may result from poor nighttime sleep due to sleep disordered breathing, fragmented sleep, or other sleep disorders. Daytime sleepiness may be associated with cognition in older adults.

Objectives

We investigated the association between self-reported daytime sleepiness and cognitive function in the Look AHEAD clinical trial.

Design

Observational follow-up of a randomized clinical trial of an intensive lifestyle intervention.

Setting

Clinic.

Participants

Participants (n=1,778) aged 45-76 years at baseline with type 2 diabetes and overweight or obesity.

Interventions

Participants were randomized to an intensive lifestyle intervention for weight loss or a control condition of diabetes support and education.

Measurements

Participants provided self-reported levels of daytime sleepiness at baseline and years 12-13. Cognitive function was assessed with a neurocognitive battery at years 12-13 and 18-20.

Results

Participants who reported having frequent daytime sleepiness (often or always) performed significantly worse than others on the cognitive composite (-0.35; p-value=0.014) after controlling for covariates. When stratified by intervention arm, participants assigned to the intensive lifestyle intervention who reported often/always having daytime sleepiness performed worse on Digit Symbol Coding (-0.63; p-value=0.05) and Trail Making Part-B (-0.56; p-value=0.02) after controlling for covariates. Statistical interactions revealed associations between daytime sleepiness and the following covariates: race and ethnicity, APOE ε4 carrier status, baseline history of cardiovascular disease, and depression.

Conclusions

Daytime sleepiness over ~13 years predicted poorer cognitive performance in older individuals who, by virtue of having diabetes and overweight/obesity, are at high risk for sleep disorders and cognitive impairment.

Safety and tolerability of high-dose daily vitamin D3 supplementation in the vitamin D and type 2 diabetes (D2d) study-a randomized trial in persons with prediabetes

BACKGROUND/OBJECTIVES

Routine use of vitamin D supplements has increased substantially in the United States. However, the safety and tolerability of long-term use of high-dose vitamin D are not known. We assessed the safety and tolerability of high-dose, daily vitamin D₃ in the vitamin D and type 2 diabetes (D2d) study.

SUBJECTS/METHODS

In total, 2423 overweight/obese persons with prediabetes were randomized in a double-blind manner to either 4000 IU of vitamin D₃ (the tolerable upper intake level for adults by the National Academy of Medicine) taken daily or matching placebo. All participants were included in this analysis. Incident adverse events (AE) were ascertained 4 times a year at in-person visits (twice a year) and interim remote encounters (twice a year) and were defined as untoward or unfavorable medical occurrences. Serious adverse events (SAE) included death, life-threatening events, and hospitalizations.

RESULTS

A total of 8304 AEs occurred during 3 years of follow-up and were less frequent in the vitamin D group compared to placebo (Incidence Rate Ratio [IRR] = 0.94; 95% Confidence Interval (CI) 0.90, 0.98). The overall frequency of protocol-specified AEs of interest, which included nephrolithiasis, hypercalcemia, hypercalciuria, or low estimated glomerular filtration rate, was low and did not differ by group. There were no significant between-group differences in total SAEs (IRR = 0.96 (0.81, 1.14)).

CONCLUSION

Vitamin D₃ supplementation at 4000 IU per day was safe and well tolerated among overweight/obese participants at high risk for diabetes who were appropriately monitored for safety. In this population, this dose of vitamin D₃ did not increase risk of AEs or SAEs, including those previously associated with vitamin D such as hypercalcemia, hypercalciuria, or nephrolithiasis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT01942694, prospectively registered September 16, 2013.

Safety and Tolerability of Vitamin D Supplementation in the Vitamin D and Type 2 Diabetes (D2d) Study – A Randomized Trial in Persons With Prediabetes

Objectives

The routine use of vitamin D supplements has increased substantially in the United States. However, the safety and tolerability of long-term use of high-dose vitamin D are unknown. We assessed the safety and tolerability of vitamin D3 at a dose of 4000 IU daily in the vitamin D and type 2 diabetes (D2d) trial.

Methods

Persons with overweight/obesity and prediabetes without a recent history of nephrolithiasis, hypercalcemia, hypercalciuria, or other conditions potentially associated with vitamin D use, were randomized to either daily 4000 IU of vitamin D3 or placebo. Participants were allowed to take vitamin D up to 1000 IU/day and calcium up to 600 mg/day, in addition to study medication. Incident adverse events (AE), defined as any untoward or unfavorable medical occurrence, were ascertained in both groups at in-person visits and interim phone or email encounters four times a year. Serious AEs (SAE) were defined as those AEs that resulted in death, new or prolonged hospitalization, persistent or significant disability, or congenital anomaly or birth defect, or were life threatening or represented another significant hazard.

Results

A total of 8,304 AEs occurred during three years of follow-up. AEs were less frequent in the vitamin D group compared to placebo [4039 (116.1 events per 100 person-years) vs. 4265 (123.8 events per 100 person-years) (Incidence Rate Ratio [IRR] = 0.94; 95% Confidence Interval (CI) 0.90, 0.98)]. The overall frequency of protocol-specified AEs of interest was low, including nephrolithiasis, hypercalcemia, hypercalciuria, and low estimated glomerular filtration rate (eGFR) with no significant between-group differences. There were also no significant differences between the vitamin D and placebo groups in SAEs (IRR = 0.95; 95% CI 0.81, 1.13).

Conclusions

Vitamin D3 supplementation at 4,000 IU per day was safe and well-tolerated and did not increase risk of AEs or SAEs, including those typically associated with vitamin D excess such as hypercalciuria or nephrolithiasis.

Funding Sources

National Institute of Diabetes and Digestive and Kidney Diseases, Office of Dietary Supplements of the National Institutes of Health, the American Diabetes Association.

Patient Selection for Intensive Blood Pressure Management Based on Benefit and Adverse Events

BACKGROUND

Intensive systolic blood pressure (SBP) treatment prevents cardiovascular disease (CVD) events in patients with high CVD risk on average, though benefits likely vary among patients.

OBJECTIVES

The aim of this study was to predict the magnitude of benefit (reduced CVD and all-cause mortality risk) along with adverse event (AE) risk from intensive versus standard SBP treatment.

METHODS

This was a secondary analysis of SPRINT (Systolic Blood Pressure Intervention Trial). Separate benefit outcomes were the first occurrence of: 1) a CVD composite of acute myocardial infarction or other acute coronary syndrome, stroke, heart failure, or CVD death; and 2) all-cause mortality. Treatment-related AEs of interest included hypotension, syncope, bradycardia, electrolyte abnormalities, injurious falls, and acute kidney injury. Modified elastic net Cox regression was used to predict absolute risk for each outcome and absolute risk differences on the basis of 36 baseline variables available at the point of care with intensive versus standard treatment.

RESULTS

Among 8,828 SPRINT participants (mean age 67.9 years, 35% women), 600 CVD composite events, 363 all-cause deaths, and 481 treatment-related AEs occurred over a median follow-up period of 3.26 years. Individual participant risks were predicted for the CVD composite (C index = 0.71), all-cause mortality (C index = 0.75), and treatment-related AEs (C index = 0.69). Higher baseline CVD risk was associated with greater benefit (i.e., larger absolute CVD risk reduction). Predicted CVD benefit and predicted increased treatment-related AE risk were correlated (Spearman correlation coefficient = -0.72), and 95% of participants who fell into the highest tertile of predicted benefit also had high or moderate predicted increases in treatment-related AE risk. Few were predicted as high benefit with low AE risk (1.8%) or low benefit with high AE risk (1.5%). Similar results were obtained for all-cause mortality.

CONCLUSIONS

SPRINT participants with higher baseline predicted CVD risk gained greater absolute benefit from intensive treatment. Participants with high predicted benefit were also most likely to experience treatment-related AEs, but AEs were generally mild and transient. Patients should be prioritized for intensive SBP treatment on the basis of higher predicted benefit. (Systolic Blood Pressure Intervention Trial [SPRINT]; NCT01206062).

Weight Change 2 Years After Termination of the Intensive Lifestyle Intervention in the Look AHEAD Study

OBJECTIVE

This study evaluated weight changes after cessation of the 10-year intensive lifestyle intervention (ILI) in the Look AHEAD (Action for Health in Diabetes) study. It was hypothesized that ILI participants would be more likely to gain weight during the 2-year observational period following termination of weight-loss-maintenance counseling than would participants in the diabetes support and education (DSE) control group.

METHODS

Look AHEAD was a randomized controlled trial that compared the effects of ILI and DSE on cardiovascular morbidity and mortality in participants with overweight/obesity and type 2 diabetes. Look AHEAD was converted to an observational study in September 2012.

RESULTS

Two years after the end of the intervention (EOI), ILI and DSE participants lost a mean  (SE) of 1.2  (0.2) kg and 1.8  (0.2) kg, respectively (P = 0.003). In addition, 31% of ILI and 23.9% of DSE participants gained ≥ 2% (P < 0.001) of EOI weight, whereas 36.3% and 45.9% of the respective groups lost ≥ 2% of EOI weight (P = 0.001). Two years after the EOI, ILI participants reported greater use of weight-control behaviors than DSE participants.

CONCLUSIONS

Both groups lost weight during the 2-year follow-up period, but more ILI than DSE participants gained ≥ 2% of EOI weight. Further understanding is needed of factors that affected long-term weight change in both groups.

History of Cardiovascular Disease, Intensive Lifestyle Intervention, and Cardiovascular Outcomes in the Look AHEAD Trial

OBJECTIVE

To examine the effects of an intensive lifestyle intervention (ILI) on cardiovascular disease (CVD), the Action for Health in Diabetes (Look AHEAD) trial randomized 5,145 participants with type 2 diabetes and overweight/obesity to a ILI or diabetes support and education. Although the primary outcome did not differ between the groups, there was suggestive evidence of heterogeneity for prespecified baseline CVD history subgroups (interaction P = 0.063). Event rates were higher in the ILI group among those with a CVD history (hazard ratio 1.13 [95% CI: 0.90-1.41]) and lower among those without CVD (hazard ratio 0.86 [95% CI: 0.72-1.02]).

METHODS

This study conducted post hoc analyses of the rates of the primary composite outcome and components, adjudicated cardiovascular death, nonfatal myocardial infarction (MI), stroke, and hospitalization for angina, as well as three secondary composite cardiovascular outcomes.

RESULTS

Interaction P values for the primary and two secondary composites were similar (0.060-0.064). Of components, the interaction was significant for nonfatal MI (P = 0.035). This interaction was not due to confounding by baseline variables, different intervention responses for weight loss and physical fitness, or hypoglycemic events. In those with a CVD history, statin use was high and similar by group. In those without a CVD history, low-density lipoprotein cholesterol levels were higher (P = 0.003) and statin use was lower (P ≤ 0.001) in the ILI group.

CONCLUSIONS

Intervention response heterogeneity was significant for nonfatal MI. Response heterogeneity may need consideration in a CVD-outcome trial design.

Polytobacco Use Among a Nationally Representative Sample of Adolescent and Young Adult E-Cigarette Users

PURPOSE

Electronic nicotine delivery systems (ENDS) are adolescents' most commonly used tobacco product and young adults' second most used. Little is known about ENDS use alongside other tobacco products (polytobacco use) and whether exclusive ENDS users differ from polytobacco ENDS users.

METHODS

In spring 2016, we surveyed a nationally representative sample of 3,517 13-25-year olds (36.9% 13-17-year olds), and examined sociodemographic and relative risk perceptions between two groups of past 30-day ENDS users: exclusive (only ENDS) and polytobacco (ENDS and at least one other tobacco product).

RESULTS

4.5% of adolescents and 10% of young adults reported past 30-day ENDS use (n = 281; analytic sample). ENDS users were 38.8% female and 70.6% white. Over half (55.9%) were polytobacco ENDS users. The most common patterns of polytobacco ENDS use were ENDS and cigarettes (11.5%), ENDS and cigars (7.7%), and ENDS, cigars, and waterpipe (5.2%). Those who perceived ENDS to be less harmful than cigarettes were more likely to be exclusive ENDS users than those who perceived ENDS to be as or more harmful than cigarettes (adjusted odds ratio = 2.6, confidence interval = 1.2, 5.7). There were no differences between ENDS groups on age, race, sex, parental education, sexual orientation, or ENDS use frequency.

CONCLUSIONS

Just over half of ENDS users also used other tobacco products, increasing their risk for nicotine addiction and other health harms. The Food and Drug Administration is responsible for communicating product risk to consumers and should consider common patterns of use and relative risk perceptions in its ENDS public education efforts.

Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes

BACKGROUND

Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients.

METHODS

In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years.

RESULTS

The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51).

CONCLUSIONS

An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).

Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes

BACKGROUND

Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients.

METHODS

In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years.

RESULTS

The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51).

CONCLUSIONS

An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).

Poor health-related quality of life prior to ECT in depressed patients normalizes with sustained remission after ECT

BACKGROUND

Health-related quality of life (HRQOL) is diminished in depressed adult outpatients and especially impaired among depressed patients referred for ECT. We compare pretreatment HRQOL in ECT and non-ECT depressed patients from two large samples, and examined whether sustained remission in depressive symptoms after ECT is associated with normalization of HRQOL.

METHODS

HRQOL was measured with the Medical Outcomes Study Short Form 36 (SF36) before ECT and 6 months after ECT in an effectiveness (n=286) and an efficacy (n=243) clinical trial.

RESULTS

ECT patients had very low baseline SF36 scores. With one exception, SF36 subscale scores in both trials were significantly lower than those of depressed outpatients. A minority of patients in both trials entered and sustained remission over the 24 week timeframe. Among sustained remitters, average SF36 scores were no different from normative scores of the general adult population, except that in the effectiveness study ECT patients reported less Bodily Pain (p<0.05) and better Mental Health (p<0.05), while in the efficacy study ECT patients reported more difficulty with Role-Emotional (p<0.01).

LIMITATIONS

Only a modest number of patients were observed in sustained remission.

CONCLUSIONS

HRQOL is very poor in patients referred for ECT. Depressed patients who experience sustained remission after ECT, however, can expect improvement in their quality of life that leaves many in a position indistinguishable from the general adult population.

The relationship between obstructive sleep apnea and self-reported stroke or coronary heart disease in overweight and obese adults with type 2 diabetes mellitus

STUDY OBJECTIVES

Type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) are common, increasingly recognized as comorbid conditions, and individually implicated in the development of cardiovascular disease (CVD). We sought to determine the association between OSA and CVD in an overweight and obese population with T2DM.

DESIGN

Cross-sectional.

SETTING

Ancillary study to the Look AHEAD trial.

PARTICIPANTS

Three hundred five participants of the Sleep AHEAD study who underwent unattended full polysomnography at home with measurement of the apnea-hypopnea index (AHI).

MEASUREMENTS AND RESULTS

Self-reported prevalent CVD was obtained at the initial assessment of the parent study and included a history of the following conditions: stroke, carotid endarterectomy, myocardial infarction, coronary artery bypass grafting, and percutaneous coronary intervention. Logistic regression was used to assess the association of OSA, measured continuously and categorically, with prevalent CVD. OSA was present (AHI ≥ 5) in 86% of the population, whereas the prevalence of all forms of CVD was just 14%. The AHI was associated with stroke with an adjusted odds ratio (95% confidence interval) of 2.57 (1.03, 6.42). Neither the continuously measured AHI nor the categories of OSA severity were significantly associated with the other forms of CVD assessed.

CONCLUSIONS

We found suggestive evidence of a greater prevalence of stroke at greater values of the AHI. OSA was not associated with prevalent coronary heart disease in the Sleep AHEAD trial. Future studies should confirm the link between OSA and stroke and examine mechanisms that link OSA to stroke in adults with T2DM.

A randomized study on the effect of weight loss on obstructive sleep apnea among obese patients with type 2 diabetes: the Sleep AHEAD study

BACKGROUND

The belief that weight loss improves obstructive sleep apnea (OSA) has limited empirical support. The purpose of this 4-center study was to assess the effects of weight loss on OSA over a 1-year period.

METHODS

The study included 264 participants with type 2 diabetes and a mean (SD) age of 61.2 (6.5) years, weight of 102.4 (18.3) kg, body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) of 36.7 (5.7), and an apnea-hypopnea index (AHI) of 23.2 (16.5) events per hour. The participants were randomly assigned to either a behavioral weight loss program developed specifically for obese patients with type 2 diabetes (intensive lifestyle intervention [ILI]) or 3 group sessions related to effective diabetes management (diabetes support and education [DSE]).

RESULTS

The ILI participants lost more weight at 1 year than did DSE participants (10.8 kg vs 0.6 kg; P < .001). Relative to the DSE group, the ILI intervention was associated with an adjusted (SE) decrease in AHI of 9.7 (2.0) events per hour (P < .001). At 1 year, more than 3 times as many participants in the ILI group than in the DSE group had total remission of their OSA, and the prevalence of severe OSA among ILI participants was half that of the DSE group. Initial AHI and weight loss were the strongest predictors of changes in AHI at 1 year (P < .01). Participants with a weight loss of 10 kg or more had the greatest reductions in AHI.

CONCLUSIONS

Physicians and their patients can expect that weight loss will result in significant and clinically relevant improvements in OSA among obese patients with type 2 diabetes. Trial Registration clinicaltrials.gov Identifier: NCT00194259.

Obesity and albuminuria among adults with type 2 diabetes: the Look AHEAD (Action for Health in Diabetes) Study

OBJECTIVE

To determine the association between obesity measures and albuminuria in adults with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In the Look AHEAD (Action for Health in Diabetes) Study, BMI and waist circumference were measured among 4,985 participants while total percent body fat was measured by whole-body DEXA scans among 1,351 participants. Odds of albuminuria by quartiles of BMI, waist circumference, and percent total body fat were calculated using logistic regression analysis while adjusting for covariates.

RESULTS

The highest quartile of BMI (odds ratio [OR] 1.72 [95% CI 1.40-2.11]) and waist circumference (OR 1.75 [95% CI 1.42-2.15]) was significantly associated with albuminuria compared with the lowest quartile after adjustment for covariates. No associations were noted between quartiles of percent total body fat and albuminuria in any model.

CONCLUSIONS

Increased BMI and abdominal obesity are associated with albuminuria in overweight and obese adults with type 2 diabetes.

Recruitment of participants for the Estrogen Replacement and Atherosclerosis (ERA) trial. a comparison of costs, yields, and participant characteristics from community- and hospital-based recruitment strategies

This paper documents recruitment for the Estrogen Replacement and Atherosclerosis trial, a multicenter, placebo-controlled, double-blind angiographic trial of the effects of opposed and unopposed estrogen on coronary atherosclerosis in postmenopausal women (average scheduled duration of follow-up 3.2 years). We compare costs, yields, and participant characteristics between community-based and hospital-based recruitment strategies. We further compare community-based enriched sources (i.e., those that allowed self-selection or targeted women with known health characteristics) and nonenriched sources. Data gathered on potential participants include method of contact, clinical site, eligibility, completion of screening visits, and randomization rates. Demographic data on participants include age, race, education, marital status, and income. Self-reported health status, smoking status, lipid level, ejection fraction as well as history of chest pain, hypertension, and diabetes were recorded at baseline. Recruitment costs were estimated from employee salaries and costs of screening tests and procedures. Yields were compared by clinical site and by method of contact. Enriched sources of recruitment yielded higher percentages of enrolled participants than nonenriched sources. Both types of source resulted in demographically similar participants. Costs of community-based recruitment were less than hospital-based recruitment; however, screening costs were higher. Overall, screening and recruitment averaged $2508 per randomized participant. Control Clin Trials 2001;22:13-25

Detection of peri-implant bone changes with axial tomosynthesis

Tuned aperture computed tomography was used to assess bone defects at implant sites that are normally obscured in conventional periapical projections. Titanium implants were placed in incisor, premolar, and molar areas of an edentulous dry human mandible. The alveolar crest adjacent to each implant was circumferentially grooved with progressively larger round burs (no. 1/4 to no. 6). After each increment of bone removal, axial tuned aperture computed tomography slice images were produced. From these, digital subtraction images were generated with incremental and baseline slices. A panel of eight dentists reviewed randomized pairs of images that showed defects that differed by a single bur size. Images were masked to limit observation to mesial, distal, facial, or lingual regions. Observers accurately identified larger lesions in 76% of the unsubtracted tuned aperture computed tomography images and in 90% of the subtracted images. Logistic regression analysis suggested significant differences as a result of lesion size (p < 0.036) and imaging modality (p < 0.020).

Subjective estimates of sleep differ from polysomnographic measurements in obstructive sleep apnea patients

It is well established that, as a group, insomnia patients overestimate sleep onset latency (SOL) and underestimate total sleep time (TST) when compared to objective polysomnographic (PSG) findings. Whether a similar phenomenon occurs with other sleep disorders is not fully established. We compared the PSG sleep of 84 patients with suspected sleep apnea (SA) to their subjective experience of sleep reported on a sleep diary the morning after PSG testing. Both patients with SA (SA+) and those without (SA-) tended to overestimate SOL, but the SA+ group (n = 50) made larger overestimations (p < 0.02). The SA+ and SA- groups also differed in their accuracy at estimating TST, with SA+ patients underestimating TST (p < 0.05). These findings support the premise that marked discrepancies between subjective and PSG-determined sleep may not be limited to insomnia, but present in other sleep disorders as well, and should be appreciated by practitioners when obtaining sleep histories.

Comparison of a novel tropane analog of cocaine, 2 beta-propanoyl-3 beta-(4-tolyl) tropane with cocaine HCl in rats: nucleus accumbens extracellular dopamine concentration and motor activity

2 beta-propanoyl-3 beta-(4-tolyl) tropane (PTT) is a novel tropane that has been shown to be approximately 20 times more potent than cocaine in binding to the 3 beta-[4'-iodophenyl] tropane-2 beta-carboxylic acid methyl ester (RTI-55) site on the dopamine transporter, an effect partially attributable to the methyl constituent at the para position on the phenyl ring. In addition, PTT lacks the ester linkage of cocaine, thus increasing its metabolic stability. This study was undertaken to compare the quantitative and temporal effects of PTT and cocaine on in vivo neurochemical measures and motor behavior. The effects of PTT (0.3, 1.0 and 3.0 mg/kg; i.p.) and cocaine HCl (3.0, 10.0, & 30.0 mg/kg; i.p.) on nucleus accumbens extracellular dopamine concentrations [DA]e were evaluated using in vivo microdialysis. Locomotor activity and stereotypic behaviors were also assessed. PTT and cocaine increased [DA]e and total locomotor activity in a dose-dependent manner with PTT approximately 30 times more potent than cocaine. The relationship between [DA]e and locomotor activity was linear over the test session for cocaine, but not for PTT. In a subsequent experiment, pronounced stereotypic behaviors were evident in rats administered cocaine (10.0 and 30.0 mg/kg) or PTT (3.0 mg/kg). The stereotypy elicited by PTT was longer in duration and greater in intensity than that elicited by the highest dose of cocaine. These results extend previously published data by demonstrating similar in vivo potencies for PTT on nucleus accumbens [DA]e and locomotor activity. However, these data do not support the hypothesis that the time course of increased nucleus accumbens [DA]e and stimulated locomotor activity are related.

Three-dimensional MRI of the glenoid labrum

The objective of this study was to assess the accuracy of three-dimensional (3D) magnetic resonance imaging (MRI) reformation in the evaluation of tears of the glenoid labrum complex (GLC). Fifty-five shoulders were evaluated by MRI using standard spin-echo sequences. Gradient-refocused-echo axial projections were used to assess the GLC on the two-dimensional (2D) studies. Three-dimensional Fourier transform multiplanar gradient-recalled imaging with a resolution of 0.7 mm was also performed in all patients. Independent analyses of the anterior and posterior labra were performed in a blinded manner for both the 2D and 3D studies by three experienced musculoskeletal radiologists. Observations of the imaging studies were compared with the videoarthroscopic findings. The appearance of the GLC was rated on a scale of 0 to 4 (0-2 = normal, 3, 4 = abnormal or torn). The diagnostic confidence was averaged from the three reader's scores. Anterior labral tears were effectively detected with sensitivities of 89% and 96% and specificities of 96% and 100% (P < 0.0001) for the 2D and 3D studies, respectively. For posterior labral tears, the sensitivity and specificity of the 2D method were 47% and 98%, respectively. The sensitivity and specificity of the 3D volume sequence were 53% and 98%, respectively. The lower sensitivity of both imaging methods for detecting posterior labral tears may be influenced by the smaller number (n = 5) of arthroscopically confirmed cases in our study and reflects the difficulty of visualizing the posteroinferior borders of the GLC with present MRI techniques.

Effects of duration of ischaemia during preconditioning on mechanical function, enzyme release and energy production in the isolated working rat heart

Repeated brief episodes of ischaemia "precondition" the myocardium and protect it during a subsequent period of sustained ischaemia. We subjected isolated rat hearts to sustained ischaemia with or without reperfusion after different schedules of preconditioning. We demonstrated that preconditioning with three 5 min periods of ischaemia separated by 10 min periods of reperfusion permits better functional recovery than preconditioning with three 2 min ischaemic periods separated by 10 min of reperfusion. Preconditioned hearts had creatine phosphate and adenine nucleotide levels comparable to those in the aerobically perfused controls, and showed good functional recovery. Although the mechanisms by which preconditioning protects the heart from subsequent ischaemic damage are unclear, we speculate that preservation of mitochondrial function and oxidative energy production is involved.

Contraceptive method switching over women's reproductive careers: evidence from Malaysian life history data, 1940s-70s

Several new concepts are used to describe contraceptive use histories for nearly 1200 women in Peninsular Malaysia. These histories are summarized by 81 episode histories. Transition matrices provide useful summaries of the changes women make in their contraceptive practice from one pregnancy interval to the next. Data from the mid-1940s to mid-1970s, during which period there was a dramatic increase in contraceptive use, reveal considerable inertia in individual couples' contraceptive practice. Persistence with a method was greater the less effective the method: while 86% of couples using no method in one interval used no method in the next, only 56% of couples using the pill in one interval also used it in the next. Virtually all transitions are of three types: continuation with the same method, a change from no method to some method, or a change from some method to no method. For only 1% of all pregnancies did couples use one contraceptive method before a pregnancy and a different method after the pregnancy. Differences are examined by calendar year and education.