The role of Mfn2 in the structure and function of endoplasmic reticulum-mitochondrial tethering in vivo

Mitochondria-endoplasmic reticulum contacts (MERCs) play an essential role in multiple cell physiological processes. Although Mfn2 was the first protein implicated in the formation of MERCs, there is debate as to whether it acts as a tether or antagonizer, largely based on in vitro studies. To understand the role of Mfn2 in MERCs in vivo, we characterized ultrastructural and biochemical changes of MERCs in pyramidal neurons of hippocampus in Mfn2 conditional knockout mice and in Mfn2 overexpressing mice, and found that Mfn2 ablation caused reduced close contacts, whereas Mfn2 overexpression caused increased close contacts between the endoplasmic reticulum (ER) and mitochondria in vivo. Functional studies on SH-SY5Y cells with Mfn2 knockout or overexpression demonstrating similar biochemical changes found that mitochondrial calcium uptake along with IP3R3-Grp75 interaction was decreased in Mfn2 knockout cells but increased in Mfn2 overexpressing cells. Lastly, we found Mfn2 knockout decreased and Mfn2 overexpression increased the interaction between the ER-mitochondria tethering pair of VAPB-PTPIP51. In conclusion, our study supports the notion that Mfn2 plays a critical role in ER-mitochondrial tethering and the formation of close contacts in neuronal cells in vivo.

0706 Comparing the Dose-Response Curves of Upper Airway Stimulation and CPAP Usage on Changes in Epworth Sleepiness Scale

Introduction

Upper Airway Stimulation (UAS) and Continuous Positive Airway Pressure (CPAP) are trackable therapies for obstructive sleep apnea. We used recent big-data cohorts to compare changes in sleepiness versus usage.

Methods

ADHERE is an international registry of real-world UAS outcomes from 2016 to date. General UAS criteria are CPAP intolerance, AHI 15-65 (<25% central+mixed), and suggested BMI≤35. Baseline ESS is collected from the medical record, and follow-up ESS and usage is collected 2-4 months after therapy activation. M Health Fairview maintains a database of cross-linked CPAP and EHR data. All new adult sleep patients from 2015 onward were included paralleling ADHERE: BMI≤35, AHI 15-65, and daily CPAP-EHR data starting at least 60 days prior to 2nd ESS measurement. Baseline ESS was collected at consult, and follow-up ESS was collected approximately 6 months later. Device-reported usage hours were compared with the changes in ESS from baseline.

Results

UAS (n=690) and CPAP (n=514) groups were similar: age 59.7±10.8 versus 59.7±13.6, 78% versus 75% male, and AHI 35.3±14.4 versus 33.8±14.0. UAS group was slightly less obese, BMI 29.3±3.9 versus 30.0±3.4 (p=0.001), with higher baseline ESS, 11.4±5.6 versus 8.6±5.3 (p<0.001). UAS usage was higher at 6.4±2.0 hours/night versus 5.2±2.0 hours/night with CPAP (p<0.001). UAS group average ESS decreased 2.5 points for patients with 0-4 hours of use (n=81), decreasing to 3.8 points with at 4 or more hours of use (n=609). CPAP group average ESS decreased 2.5 points for patients with 0-4 hours of use (n=125), decreasing to 3.3 points with at 4 or more hours of use (n=389).

Conclusion

Compared to prior works and the UAS cohort, this CPAP cohort was more likely to have normal ESS at baseline. UAS and CPAP both demonstrate a dose-response curve associating increasing hourly usage with larger ESS reductions.

Support

Kent Lee of Inspire Medical Systems provided background information and access to a de-identified ADHERE data set for analysis.

Mfn2 ablation causes an oxidative stress response and eventual neuronal death in the hippocampus and cortex

Background

Mitochondria are the organelles responsible for energy metabolism and have a direct impact on neuronal function and survival. Mitochondrial abnormalities have been well characterized in Alzheimer Disease (AD). It is believed that mitochondrial fragmentation, due to impaired fission and fusion balance, likely causes mitochondrial dysfunction that underlies many aspects of neurodegenerative changes in AD. Mitochondrial fission and fusion proteins play a major role in maintaining the health and function of these important organelles. Mitofusion 2 (Mfn2) is one such protein that regulates mitochondrial fusion in which mutations lead to the neurological disease.

Methods

To examine whether and how impaired mitochondrial fission/fusion balance causes neurodegeneration in AD, we developed a transgenic mouse model using the CAMKII promoter to knockout neuronal Mfn2 in the hippocampus and cortex, areas significantly affected in AD.

Results

Electron micrographs of neurons from these mice show swollen mitochondria with cristae damage and mitochondria membrane abnormalities. Over time the Mfn2 cKO model demonstrates a progression of neurodegeneration via mitochondrial morphological changes, oxidative stress response, inflammatory changes, and loss of MAP2 in dendrites, leading to severe and selective neuronal death. In this model, hippocampal CA1 neurons were affected earlier and resulted in nearly total loss, while in the cortex, progressive neuronal death was associated with decreased cortical size.

Conclusions

Overall, our findings indicate that impaired mitochondrial fission and fusion balance can cause many of the neurodegenerative changes and eventual neuron loss that characterize AD in the hippocampus and cortex which makes it a potential target for treatment strategies for AD.

Electronic supplementary material

The online version of this article (10.1186/s13024-018-0238-8) contains supplementary material, which is available to authorized users.

Managing cardiovascular risk factors: trial evidence in women

Cardiovascular disease remains by far the leading cause of death for women worldwide. Despite a large body of research identifying effective interventions to reduce cardiovascular risk, translation into practice has been slow. This review pinpoints areas in particular need of improvement and summarizes gender-specific analyses in recent randomized trials assessing the impact of risk factor modulation on cardiovascular events.

Access to contraceptive services among unmarried young people in the north-east of China

OBJECTIVE

The concerns about the potential threats of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) have increased, since, in China, there is a lack of sexual education and condom use is rare. A community-based survey was conducted in September 2001 in Changchun city among 1227 unmarried young people aged 15-24 years (619 males and 608 females) to assess risky sexual practices and the obstacles to accessing appropriate contraceptive and other services.

METHOD

The study comprised a survey employing self-administered questionnaires, as well as key informant interviews, focus group discussions and in-depth interviews. This paper investigates the factors associated with young people's access to contraceptive services.

RESULTS

Results showed that 16% of young people had experienced premarital sexual intercourse and, among them, only 48.2% used contraceptive methods during the first sexual intercourse; 29.9% used a condom. Drug stores were the main source of contraceptives.

CONCLUSIONS

While data are sparse, findings suggest that the hostile and judgmental attitudes of providers, as well as the lack of counseling and privacy, were the key obstacles that unmarried youth encountered in their search for contraceptive services. Findings suggest the need for a reorientation of the contraceptive services to focus on unmarried youth, and generally to make contraceptive services more accessible to young people.

Hormone replacement therapy for prevention of coronary heart disease: current evidence

Postmenopausal estrogen replacement, with or without progestin therapy, has a generally favorable impact on lipids, improves endothelial function, and has anti-inflammatory and antioxidant effects. These properties should favorably impact coronary risk; indeed, epidemiologic studies have consistently associated hormone replacement therapy with reduced coronary risk. Nonetheless, the Heart & Estrogen/progestin Replacement Study (HERS), a randomized, placebo-controlled, secondary prevention trial of conjugated estrogen with progestin, found no overall reduction in coronary events among women assigned to active hormone treatment. This review explores the role of estrogen replacement among interventions intended to prevent coronary heart disease in the post-HERS era.

Postmenopausal hormone therapy and risk of stroke: The Heart and Estrogen-progestin Replacement Study (HERS)

BACKGROUND

Observational studies have shown that postmenopausal hormone therapy may increase, decrease, or have no effect on the risk of stroke. To date, no clinical trial has examined this question. To investigate the relation between estrogen plus progestin therapy and risk of stroke among postmenopausal women, we analyzed data collected from the Heart & Estrogen-progestin Replacement Study (HERS), a secondary coronary heart disease prevention trial.

METHODS AND RESULTS

Postmenopausal women (n=2763) were randomly assigned to take conjugated estrogen plus progestin or placebo. Primary outcomes for these analyses were stroke incidence and stroke death during a mean follow-up of 4.1 years. The number of women with strokes was compared with the number of women without strokes. A total of 149 women (5%) had 1 or more strokes, 85% of which were ischemic, resulting in 26 deaths. Hormone therapy was not significantly associated with risk of nonfatal stroke (relative hazard [RH] 1.18; 95% CI 0.83 to 1.66), fatal stroke (RH 1.61; 95% CI 0.73 to 3.55), or transient ischemic attack (RH 0.90; 95% CI 0.57 to 1.42). Independent predictors of stroke events included increasing age, hypertension, diabetes, current cigarette smoking, and atrial fibrillation. Black women were at increased risk compared with white women, and unexpectedly, body mass index was inversely associated with stroke risk.

CONCLUSIONS

Hormone therapy with conjugated equine estrogen and progestin had no significant effect on the risk for stroke among postmenopausal women with coronary disease.

Peripheral arterial disease in randomized trial of estrogen with progestin in women with coronary heart disease: the Heart and Estrogen/Progestin Replacement Study

BACKGROUND

Postmenopausal estrogen use has been associated with reduced carotid atherosclerosis in observational studies, but this relationship has not been confirmed in a clinical trial. The impact of estrogen on atherosclerotic disease in other peripheral arteries is unknown.

METHODS AND RESULTS

Postmenopausal women with coronary heart disease (CHD) and an intact uterus (n=2763) were randomly assigned to conjugated equine estrogens (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg) daily or to placebo in a secondary CHD prevention trial. This analysis focuses on incident peripheral arterial procedures and deaths in the 2 treatment groups; peripheral vascular disease was a predefined secondary outcome. During a mean of 4.1 years of follow-up, 311 peripheral arterial events were reported in 213 women, an annual incidence of 2.9%. The number of women who had peripheral arterial events was 99 among those assigned to active estrogen/progestin and 114 among those assigned to placebo, a nonsignificant difference (relative hazard 0. 87, 95% CI 0.66 to 1.14). In the placebo group, hypertension and diabetes mellitus were independently associated with higher rates of peripheral arterial events, and plasma HDL cholesterol and body mass index were associated with lower rates of peripheral arterial events. In the estrogen/progestin group, current smoking and diabetes were independent predictors of peripheral arterial events. Incident peripheral arterial disease was not a significant predictor of coronary, cardiovascular, or total mortality.

CONCLUSIONS

Treatment with oral conjugated estrogen plus medroxyprogesterone acetate was not associated with a significant reduction in incident peripheral arterial events in postmenopausal women with preexisting CHD.

Is insurance a more important determinant of healthcare access than perceived health? Evidence from the Women's Health Initiative

Our objectives were to explore health insurance status and insurance type, adjusted for self-reported and perceived health variables, as determinants of having and using a usual care provider in the Women's Health Initiative (WHI) Observational Study (OS). This analysis describes insurance status in a large, diverse group of older women and tests the hypothesis that insurance was a key predictor of their access to healthcare in the mid-1990s. Multiple logistic regression analysis was used to evaluate determinants of having visited a usual healthcare provider within the proceeding 12 months, using cross-sectional information provided by a population-based cohort of 55,278 postmenopausal women. Five percent of women younger than 65 years and 0.2% of women 65 or older in the OS cohort lacked health insurance. Among the 31,684 women, aged 50-64 years, Hispanic women and those with fewer years of education and lower household income and who were current smokers were less likely, and those lacking insurance were the least likely, to have seen their healthcare provider within the preceding year. Among 23,594 women, aged 65-79 years, African American and Hispanic women and those with lower household income, and Medicare only and those who were current smokers, were less likely to have seen their healthcare provider within the preceding year. In both age groups, women with chronic medical conditions and poorer perceived health scores and those with prepaid insurance were more likely to have seen their healthcare provider. In the WHI OS, both health (self-reported and perceived) and type of health insurance remained independently associated with having visited a usual healthcare provider after multivariate adjustment for one another as well as for pertinent sociodemographic characteristics.

The importance of health insurance as a determinant of cancer screening: evidence from the Women's Health Initiative

BACKGROUND

Amid current changes in health care access across the United States, the importance of health insurance status and insurance type relative to demographic, actual, and perceived health variables as determinants of screening for breast, colorectal, and cervical cancer is uncertain. This analysis evaluates the hypothesis that health insurance independently predicts cancer screening in the Women's Health Initia tive Observational Study cohort.

METHODS

Questionnaire data from 55,278 women en rolled in the Women's Health Initiative Observational Study between September 1994 and February 1997 were analyzed by multiple logistic regression to identify predictors of self-reported mammography within 2 years, Pap smear within 3 years, and stool guaiac or flexible sigmoidoscopy within 5 years.

RESULTS

Positive determinants of reporting cancer screening were age, ethnic origin, household income, educational level, family history of cancer, having a usual care provider, time since last provider visit, and insurance status and type. Smoking, diabetes, and, among older women, prior cardiovascular events were negative determinants of cancer screening. Among women younger than 65, lacking health insurance or having fee-for-service insurance was strongly associated with failure to report cancer screening, independently of having or using a usual care provider and of demographics, self-perceived health, and health characteristics. Among women 65 and older, those with Medicare alone were less likely, whereas those with Medicare + prepaid insurance were more likely, to report cancer screening.

CONCLUSIONS

In the Women's Health Initiative Obser vational Study, a large, diverse group of older women, health insurance type and status were among the most important determinants of cancer screening indepen dent of demographics, chronic health conditions, and self-perceived health characteristics.

Treatment of leg telangiectasia using a long-pulse dye laser at 595 nm

BACKGROUND AND OBJECTIVE

Pulsed dye lasers (PDL) operating at 585 nm wavelength and 0.45 msec pulsewidth offer effective treatment for port wine stains (PWS). Vessels in leg telangiectasias are larger than those in PWS. Longer pulsewidths and wavelengths may improve clearance of these larger vessels.

STUDY DESIGN/MATERIALS AND METHODS

Twenty patients were treated using PDL at 595 nm and 1.5 msec. Vessel diameters ranging from 0.635 to 1.067 mm were treated using energy densities of 15 and 18 J/cm2, and a 2 x 7 mm elliptical spot. Telangiectasia clearance and complications were scored at 6-weeks and 5-months following the single treatment.

RESULTS

Results demonstrated > 50% clearance by 6 weeks in 11/26 (42.3%) patients using 15 J/cm2, and 6/13 (45.2%) using 18 J/cm2. By 5 months > 50% clearance was noted in 18/34 (53.0%) using 15 J/cm2, and 11/17 (64.7%) using 18 J/cm2. Complications were minor and infrequent.

CONCLUSION

The long-pulse PDL may have a role in treating leg telangiectasias.

Nonablative skin remodeling: selective dermal heating with a mid-infrared laser and contact cooling combination

BACKGROUND AND OBJECTIVE

Many of the microscopic changes associated with photodamage reside in the dermis. It follows that subsurface heating of the skin might allow for cosmetic enhancement without loss of the epidermis. Accordingly, we investigated the clinical and microscopic changes produced by a mid-infrared laser coupled with a contact cooling device.

STUDY DESIGN/MATERIALS AND METHODS

Nine patients were treated with an erbium glass laser and sapphire cooling handpiece in contact with the skin. Postauricular sites were irradiated with pulse energies varying from 400-1,200 mJ and numbers of pulses from 4 to 40. Outcome measures included pain, edema, and erythema at predetermined postoperative intervals. Biopsies were performed just after treatment and 2 months postoperatively for selected pulse energy-pulse number combinations.

RESULTS

Erythema, edema, and pain increased with pulse energy and number of pulses. Likewise, immediate epidermal necrosis and subsequent scarring were observed for larger pulse energy-pulse number combinations. At sites with epidermal preservation, on biopsy, immediate dermal thermal damage was observed in a band-like pattern. The deep boundaries of this band were dependent on pulse energy and pulse number. After 8 weeks, biopsies showed dermal fibroplasia roughly correlating to the band of immediate dermal thermal damage.

CONCLUSION

Selective dermal heating can be achieved with a mid-infrared laser coupled to a contact surface cooling device. In this study, the range of fibroplasia and lack of clinically substantial cosmetic enhancement suggest that the dermal thermal damage achieved may be too deep and that the injury should be confined to more superficial levels to alter the most severely photodamaged dermis. Lasers Surg. Med. 26:186-195, 2000. Published 2000 Wiley-Liss, Inc.

Peripartum cardiomyopathy: National Heart, Lung, and Blood Institute and Office of Rare Diseases (National Institutes of Health) workshop recommendations and review

OBJECTIVE

Peripartum cardiomyopathy (PPCM) is a rare life-threatening cardiomyopathy of unknown cause that occurs in the peripartum period in previously healthy women. In April 1997, the National Heart, Lung, and Blood Institute (NHLBI) and the Office of Rare Diseases of the National Institutes of Health (NIH) convened a Workshop on Peripartum Cardiomyopathy to foster a systematic review of information and to develop recommendations for research and education.

PARTICIPANTS

Fourteen workshop participants were selected by NHLBI staff and represented cardiovascular medicine, obstetrics, immunology, and pathology. A representative subgroup of 8 participants and NHLBI staff formed the writing group for this article and updated the literature on which the conclusions were based. The workshop was an open meeting, consistent with NIH policy.

EVIDENCE

Data presented at the workshop were augmented by a MEDLINE search for English-language articles published from 1966 to July 1999, using the terms peripartum cardiomyopathy, cardiomyopathy, and pregnancy. Articles on the epidemiology, pathogenesis, pathophysiology, diagnosis, treatment, and prognosis of PPCM were included. RECOMMENDATION PROCESS: After discussion of data presented, workshop participants agreed on a standardized definition of PPCM, a general clinical approach, and the need for a registry to provide an infrastructure for future research.

CONCLUSIONS

Peripartum cardiomyopathy is a rare lethal disease about which little is known. Diagnosis is confined to a narrow period and requires echocardiographic evidence of left ventricular systolic dysfunction. Symptomatic patients should receive standard therapy for heart failure, managed by a multidisciplinary team. If subsequent pregnancies occur, they should be managed in collaboration with a high-risk perinatal center. Systematic data collection is required to answer important questions about incidence, treatment, and prognosis.

Plasma homocysteine in women taking hormone replacement therapy: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial

Elevated plasma homocysteine levels have been associated with increased atherosclerotic disease risk. Estrogen and estrogen/progestin replacement therapy have been suggested to lower plasma homocysteine levels in postmenopausal women. To assess the impact of hormone replacement therapy (HRT) on plasma homocysteine, levels were measured in samples from adherent women randomized to placebo (n = 34), conjugated equine estrogens (n = 36), or continuous conjugated equine estrogens + progestin (n = 33) in the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial. Homocysteine levels decreased between baseline and follow-up (12 and 36 months) in all treatment groups. The magnitude of the reduction was greater in the conjugated estrogens group at 12 months compared with placebo (p = 0.036), even when adjusted for folate and B vitamin consumption, but this difference did not persist at 36 months. These data suggest that estrogen therapy has a modest, but transient, impact on plasma homocysteine levels in women with normal homocysteine at baseline.

Alterations in serum levels of lipids and lipoproteins with indinavir therapy for human immunodeficiency virus-infected patients

Alterations in lipid metabolism have been associated with the use of protease inhibitors. Sequential lipid analyses were performed on serum samples from human immunodeficiency virus-infected antiretroviral-naive patients who received indinavir in combination with two nucleoside reverse transcriptase inhibitors. Serum levels of cholesterol, triglycerides, high-density lipoproteins (HDLs), and low-density lipoproteins (LDLs) were measured at baseline and at periodic intervals. After 48 weeks of indinavir therapy, mean serum levels +/- SD rose as follows: cholesterol, from 167.2 +/- 36.0 to 206.3 +/- 32.4 mg/dL (P < .0005); triglycerides, from 110.4 +/- 47.5 to 158.4 +/- 72.5 mg/dL (P < .0101); and LDLs, from 106.6 +/- 35.1 to 136.1 +/- 31.6 mg/dL (P = .0029). There was no significant change in the serum HDL fraction. Mean serum lipoprotein (a) levels +/- SD rose from 6.5 +/- 1.4 to 9.6 +/- 2.0 mg/dL after 30 weeks (P = .0695). Potential mechanisms for the noted increases include alterations in serum lipoprotein lipase activity or changes in hepatic lipid metabolism. The clinical significance of these changes remains to be determined.

Evaluation and management of lipid disorders

Plasma lipids play a key role in the development of atherosclerosis. Recent trial data support early identification of asymptomatic adults with high-risk lipid profiles for primary prevention of coronary heart disease. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors have been shown to reduce coronary events in both asymptomatic adults and those with known coronary heart disease. The optimal plasma low-density lipoprotein cholesterol for secondary coronary prevention remains controversial. The Second Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II), published in 1993 by the National Cholesterol Education Program, recommends guidelines for evaluation and diagnosis of lipids. Subsequently, several clinical trials have identified populations benefiting from pharmacologic intervention and new approaches to the management of lipid disorders. Consequently, these guidelines should be applied with the interval evidence in mind.

Treatment of spider veins with the 595 nm pulsed-dye laser

BACKGROUND

Previous attempts to treat spider veins with the conventional 585 nm pulsed-dye laser with a 0.5-ms pulse duration have been relatively ineffective. Recently, a new pulsed-dye laser that is tunable from 585 to 600 nm with a pulse duration 3 times longer than previously available lasers has preliminarily been shown to be effective for treatment of spider veins.

OBJECTIVE

Our purpose was to evaluate the effectiveness of multiple treatments with the tunable long-pulse dye laser in treatment of spider veins of the lower extremity.

METHODS

Ten female volunteers were treated in two separate areas containing blue or red linear spider veins less than 1.5 mm in diameter. Treatments were administered with the pulsed-dye laser with a 1.5-ms pulse duration and 595-nm light at fluences of 15 and 20 J/cm2, and each subject received a total of 3 treatments at each site, administered at 6-week intervals. Photographs were taken before and 6 weeks after the last treatment.

RESULTS

Computer-based image analysis showed clearing of more than three fourths of veins after 3 treatments with 15 or 20 J/cm2. Side effects were minimal and the treatments were well tolerated.

CONCLUSION

The 595 nm, 1.5 ms pulse duration, pulsed-dye laser is safe and effective for treating blue or red spider veins of the lower extremities less than 1.5 mm in diameter in nontanned patients with Fitzpatrick skin types I and II. Multiple treatments improve on the results obtained after a single treatment.

Prevention of events with angiotensin-converting enzyme inhibition (the PEACE study design). Prevention of Events with Angiotensin-Converting Enzyme Inhibition

The Prevention of Events with Angiotensin-Converting Enzyme Inhibition (PEACE) trial is an 8,100 patient, randomized, double-blind, placebo-controlled trial designed to determine the usefulness of angiotensin-converting enzyme (ACE) inhibitors in treating coronary patients with preserved left ventricular ejection fraction. The hypothesis being tested in this trial is that patients with coronary disease and ejection fraction > or =40% who are treated with ACE inhibitors will experience a reduction in the incidence of cardiovascular death, nonfatal myocardial infarction, or a revascularization procedure compared with patients treated with conventional therapy. The design of the PEACE trial is described herein.

Effects of hormone replacement therapy on the circadian pattern of atherothrombotic risk factors

Onset of acute atherothrombotic events (acute myocardial infarction, unstable angina, ischemic stroke) exhibit a circadian pattern that parallels the diurnal pattern of endogenous fibrinolytic activity. Hormone replacement therapy in postmenopausal women has been shown to enhance fibrinolytic capacity by lowering plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator inhibitor (tPA) antigen values. We evaluated the impact of 4 weeks of estrogen alone (Premarin 0.625 mg/day) and 2 weeks of estrogen plus progesterone (Provera 2.5 mg/day) on PAI-1 and tPA in 17 postmenopausal women at multiple time points to assess hormone impact on the diurnal pattern of fibrinolytic potential. At baseline, both PAI-1 and tPA exhibited circadian variability. Estrogen alone selectively lowered 8 A.M. PAI-1 (35.8 +/- 7.1 ng/ml at baseline, 19.8 +/- 3.7 ng/ml on estrogen; p = 0.0002 vs baseline). There was no significant change in the noon or 4 P.M. values, and the diurnal pattern was attenuated. The 8 A.M. PAI-1 remained low at 17.1 +/- 3.6 ng/ml (p = 0.0001 vs baseline) with total loss of the circadian rhythm. Estrogen supplementation reduced tPA antigen at all time points, and the diurnal pattern, although blunted, persisted. Addition of progesterone to estrogen did not reverse effects of the estrogen alone phase of either PAI-1 or tPA values. This hormone-associated reduction of PAI-1 was observed despite increased triglycerides, a known inducer of PAI-1 levels. These observations suggest that hormone replacement therapy may protect postmenopausal women from excess early morning acute ischemic events.

Augmentation of the immune response to influenza vaccine by acetylsalicylic acid: a clinical trial in a geriatric population

The purpose of this placebo-controlled, double-blind, randomized trial was to evaluate the efficacy of oral acetylsalicylic acid (ASA), a comparatively safe, inexpensive biological response modifier, as an adjuvant to influenza vaccination in a geriatric population. 281 healthy adults, 65 years or older, received influenza vaccine and were randomized to ASA or placebo. Serum antibody against influenza A/Beijing and B/Panama, influenza antigen-stimulated blastogenesis and antigen-stimulated interleukin-2 production by peripheral blood mononuclear cells in vitro were increased following vaccination. Blastogenic response and interleukin-2 production increased to a similar extent in the two treatment groups. The proportion of participants with a 4-fold rise in specific antibody directed against influenza A/Beijing was greater among ASA recipients (p < 0.05). This difference was more marked in subjects > 75 years old (p < 0.01).

Rayleigh scattering limits for low-level bidirectional reflectance distribution function measurements

The objective is to estimate the Rayleigh limit in bidirectional reflectance distribution function (BRDF) measurements caused by air in the laboratory, the wavelength, and the path length of light in the receiver field of view. Moreover, we intend to show the trend for the reduction of this limit by introducing a medium with small refractive index and by using a longer wavelength. Although the BRDF typically describes the angular distribution of scattered light from surfaces, the expression describing the equivalent BRDF caused by the optical scattering from gas molecules in the optical path is derived through the use of the Rayleigh scattering theory. The instrumentation is described, and the experimental results of the equivalent BRDF caused by gas scattering from molecules in clear air, nitrogen, and helium gases are reported. These results confirm the trends of the prediction.

Venous embolization after deflation of lower extremity tourniquets

Massive pulmonary embolism has been reported to occur with the use of lower extremity tourniquets. We used transesophageal echocardiography to determine the incidence of venous embolism during lower extremity orthopedic surgery performed with a pneumatic tourniquet. The hemodynamic and respiratory consequences of all embolic events were assessed. Venous emboli were detected after tourniquet deflation in 8 of 30 procedures. The incidence of embolism was unrelated to the type of surgical procedure performed or the duration of tourniquet inflation. There were no significant differences in preoperative characteristics or postdeflation hemodynamic and respiratory responses between patients with and without emboli. Venous embolization is a relatively common event after tourniquet deflation. The clinical significance of these events remains to be determined.

Effects of pulse width on erbium:YAG laser photothermal trabecular ablation (LTA)

An erbium (Er):YAG laser can remove trabecular meshwork (TM) by photothermal ablation with minimal contiguous thermal damage. A variable pulse width Er:YAG laser was used to investigate the effect of varying pulse width on ablation of human TM. Trabecular photothermal ablation was performed on tissue obtained from eye bank eyes at pulse widths of 50, 150, and 250 microseconds, with energy held constant at 4 mJ. At this energy, a single laser pulse was sufficient for full-thickness ablation of TM. Laser energy was delivered through a 200-microns diameter optical fiber held in apposition to the tissue sample, which was immersed in physiologic saline. High-speed photography of the resultant steam bubbles also was performed. Light microscopy and scanning electron microscopy of TM ablated at 50 microseconds revealed the greatest variability in size (0-140 microns) of the full-thickness ablated areas and demonstrated blast effects, tissue shredding and < or = 10 microns thermal damage. At 150 microseconds, the full-thickness ablated areas were more consistent size (115-120 microns), showed no blast effects and 10 to 20 microns thermal damage. At 250 microseconds, the largest ablations were found (180-220 microns) and showed no blast damage; however, a significant amount of thermal damage (< or = 50 microns) was evident. The steam bubbles produced by the laser energy were largest at 50 microseconds and did not begin to collapse until well over twice the original pulse interval. At 150 and 250 microseconds, the steam bubbles were successively smaller and dissipated at the end of the laser pulse.(ABSTRACT TRUNCATED AT 250 WORDS)

Heparin-induced prolongation of partial thromboplastin time after thrombolysis: relation to coronary artery patency. HART Investigators

Having previously shown in the Heparin Aspirin Reperfusion Trial that the empiric use of early intravenous heparin after recombinant tissue-type plasminogen activator (rt-PA) is an important component in the overall treatment strategy, we examine in this report the specific relation between the degree of prolongation of activated partial thromboplastin time and coronary artery patency. To evaluate the hypothesis that arterial patency after administration of rt-PA for acute myocardial infarction is sustained by effective anticoagulation, activated partial thromboplastin time of heparin recipients was determined 8 and 12 h after the start of thrombolysis. Mean activated partial thromboplastin time was higher among patients with an open infarct-related artery than in those with a closed artery (81 +/- 4 vs. 54 +/- 9 s, p less than 0.02). Only 45% of patients with values less than 45 s at both 8 and 12 h had Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 in the infarct-related artery at 18 h. In contrast, 88% of patients with activated partial thromboplastin time greater than 45 s and 95% of those with values greater than 60 s had an open infarct-related artery at 18 h (p = 0.003 and 0.0006, respectively). Among patients with an initially patent infarct-related artery who underwent repeat angiography at 7 days, activated partial thromboplastin time was similar in those with a persistently patent artery and those with late reocclusion. Excessive anticoagulation did not appear to increase hemorrhagic risk except that access site-related hemorrhage was more common in patients with activated partial thromboplastin time greater than 100 s at 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of myocardial infarct artery patency on the prevalence of ventricular arrhythmia and late potentials after thrombolysis in acute myocardial infarction

Sustained infarct artery patency is an important determinant of survival in patients with acute myocardial infarction. We studied 61 patients with acute myocardial infarction who received intravenous recombinant tissue-type plasminogen activator, aspirin or heparin within 6 hours of symptom onset, to determine if infarct artery patency after intravenous thrombolytic therapy influences myocardial electrical stability as measured by the prevalence of spontaneous ventricular ectopy or late potential activity. Infarct artery patency was determined by angiographic evaluation 2.5 +/- 3 days after infarction. Forty-eight patients (79%) had a patent infarct-related artery and 13 (21%) patients had an occluded vessel. The mean number of ventricular premature complexes (VPCs)/hour (p less than 0.01) and the prevalence of late potentials (54 vs 19%; p less than 0.03) were significantly higher in patients with an occluded versus patent-infarct related vessel. Although VPC frequency and late potentials were not influenced by the time to thrombolytic treatment, patients with a patent infarct-related artery had a lower prevalence of late potentials regardless of whether treatment was initiated less than or equal to 2 hours (25% patent vs 50% occluded; p = not significant) or 2 to 6 hours (16% patent vs 55% occluded; p greater than 0.03) after symptom onset. Thus, successful thrombolysis decreases the frequency of ventricular ectopic activity and late potentials in the early postinfarction phase. The reduction in both markers of electrical instability may help explain why the prognosis after successful thrombolysis is improved after acute myocardial infarction.

Cardiac myocytes and dendritic cells harbor human immunodeficiency virus in infected patients with and without cardiac dysfunction: detection by multiplex, nested, polymerase chain reaction in individually microdissected cells from right ventricular endomyocardial biopsy tissue

Two hundred fifteen patients infected with human immunodeficiency virus (HIV) participated in a prospective longitudinal study of HIV-related heart disease. Evaluation included signal-averaged electrocardiography and echocardiography. Fifteen patients underwent endomyocardial biopsy, 5 had cardiovascular symptoms and 10 did not. Cardiac myocytes or dendritic cells were prepared by individual cell microdissection to sort them from other cell types such as interstitial cells or circulating blood elements. HIV proviral sequences were amplified in samples of 15 to 20 cells of each type by multiplex, nested, polymerase chain reaction and hybridized to 32P-labeled probes specific for regions within the gag and pol genes of HIV-1. The results showed the presence of HIV sequences in myocytes of 2 of 5 patients with cardiac symptoms and in 6 of 10 without. Thus, symptomatic HIV cardiomyopathy did not appear to be a direct consequence of the virus on myocardial cells. In dendritic cells, HIV sequences were detected in 5 of 5 patients with cardiac symptoms and in 8 of 10 with apparently normal ventricular function. Furthermore, dendritic cells were somewhat more numerous in the myocardium of symptomatic than asymptomatic patients. Our studies are the first to directly detect the HIV genome in purified cardiac myocytes from patients with and without cardiac dysfunction. Our findings do not support a direct role of the virus in myocardial dysfunction. However, the results do suggest that the interstitial dendritic cells may be involved in some manner in the development of cardiac dysfunction observed in HIV-infected patients.

Late potentials and their relation to ventricular function in human immunodeficiency virus infection

Signal-averaged electrocardiograms were performed in 225 patients with serologic evidence of human immunodeficiency virus infection as part of a prospective longitudinal study of patients with HIV-associated heart disease and 12 seronegative control subjects. The duration of signal-averaged QRS vector, root-mean-square voltage of the terminal 40 ms of the vector magnitude and the duration of the low-amplitude (less than 40 microV) signal were determined during serial visits at 4-month intervals. One or more of these variables was abnormal on initial visit in 59 of patients (26%); QRS duration was greater than 114 ms in 9 patients (4%), root-mean-square voltage less than 20 microV in 55 patients (24%) and low-amplitude signal duration greater than 39 ms in 43 (19%). In contrast, none of the seronegative control subjects had any abnormal variables (p less than 0.03). During follow-up (mean 10 +/- 8 months), 26 patients with initially normal studies developed abnormal variables and 24 with abnormal signal-averaged electrocardiograms reverted to normal. Left ventricular contractility was assessed by echocardiography using the rate-corrected velocity of fiber shortening-end-diastolic wall stress relation. Late potentials were not related to contractile abnormalities. Clinical arrhythmias were rare and did not appear more frequent among patients with late potentials. Thus, late potentials were both common and evanescent in patients infected with human immunodeficiency virus.

A comparison between heparin and low-dose aspirin as adjunctive therapy with tissue plasminogen activator for acute myocardial infarction. Heparin-Aspirin Reperfusion Trial (HART) Investigators

BACKGROUND

We report the results of the Heparin-Aspirin Reperfusion Trial, a collaborative study comparing early intravenous heparin with oral aspirin as adjunctive treatment when recombinant tissue plasminogen activator (rt-PA) is used for coronary thrombolysis during acute myocardial infarction.

METHODS

Two hundred five patients were randomly assigned to receive either immediate and then continuous intravenous heparin (starting with a 5000-unit bolus; n = 106) or immediate and then daily oral aspirin (80 mg; n = 99) together with rt-PA (100 mg intravenously over a six-hour period) initiated within six hours of the onset of symptoms. We evaluated the patency of the infarct-related artery by angiography 7 to 24 hours after beginning rt-PA infusion, the frequency of reocclusion of the artery by repeat angiography on day 7, and ischemic or hemorrhagic complications during the hospital stay.

RESULTS

At the time of the first angiogram, 82 percent of the infarct-related arteries in the patients assigned to heparin were patent, as compared with only 52 percent in the aspirin group (P less than 0.0001). Of the initially patent vessels, 88 percent remained patent after seven days in the heparin group, as compared with 95 percent in the aspirin group (P not significant). The numbers of hemorrhagic events (18 in the heparin and 15 in the aspirin group) and recurrent ischemic events (8 in the heparin and 2 in the aspirin group) were similar in the two groups.

CONCLUSIONS

Coronary patency rates associated with rt-PA are higher with early concomitant systemic heparin treatment than with concomitant low-dose oral aspirin. This observation has important implications for clinical practice and should be considered in the design and interpretation of clinical trials involving coronary thrombolytic therapy.

Peripheral blood mononuclear cell interleukin-2 and interferon-gamma production, cytotoxicity, and antigen-stimulated blastogenesis during experimental rhinovirus infection

To determine whether rhinovirus infection induced a systemic cellular immune response in humans, specific antigen-stimulated blastogenesis, natural killer cell activity, and mitogen-stimulated production of interleukin-2 and interferon-gamma by peripheral blood mononuclear cells (PBMC) were quantified during experimental rhinovirus infection of normal volunteers. Phytohemagglutinin-stimulated interleukin-2 production by PBMC collected on day 5 after rhinovirus inoculation was increased fourfold compared with production by PBMC collected before rhinovirus challenge (P less than .05); phytohemagglutinin-stimulated interferon-gamma production was doubled (P less than .05). An inverse relationship was observed between the increase in interleukin-2 production and both nasal mucus production (P less than .02) and the number of days virus was cultured from nasal washings (P less than .02). Natural killer cell-mediated cytotoxicity of PBMC collected on day 5 after rhinovirus challenge was also increased (P less than .01) compared with preinfection levels, as was specific antigen-stimulated blastogenesis on day 21 (P less than .05). The extent of blastogenic response correlated directly with both mucus production (P less than .05) and the number of days virus was cultured from nasal washings (P less than .05). These observations are consistent with the hypothesis that rhinovirus infection results in activation of a systemic cellular immune response.

Aspirin and thymosin increase interleukin-2 and interferon-gamma production by human peripheral blood lymphocytes

Interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) have recently been added to the arsenal of synthetic biological response modifiers with important immunomodulatory activities. In this paper we have assessed the effects of acetylsalicylic acid (aspirin), thymosin alpha and thymosin fraction 5 (TF5), a partially purified calf thymic preparation, on production of IFN-gamma in vitro. Stimulation by oral aspirin of IL-2 and IFN-gamma production by peripheral blood lymphocytes (PBLs) was also studied in healthy human volunteers. Aspirin, thymosin alpha 1 and TF5 were all observed to enhance phytohemagglutinin (PHA)-stimulated production of IFN-gamma. Peak IFN-gamma production by PHA-stimulated PBLs was observed after 24 h of incubation with TF5 and after 72 h with aspirin. Stimulation by aspirin and TF5 required the presence of macrophages, and was additive and dose-dependent. The additive effects of aspirin and TF5 suggest that these agents act by different mechanisms. Oral administration of aspirin in normal volunteers significantly enhanced production of both IFN-gamma and IL-2. PHA-stimulated IFN-gamma production was greatest 24 h after aspirin ingestion; in contrast, IL-2 production was optimal 10 h after aspirin ingestion. These observations suggest that oral aspirin is an effective biological response modifier in humans and raise the possibility of a novel combination approach to immunomodulation involving cyclooxygenase inhibitors and thymosins.

Antibody to the D-alanine carboxypeptidase of Bacillus subtilis does not cross-react with other penicillin-binding proteins

The fact that antibody to d-alanine carboxypeptidase of Bacillus subtilis does not cross-react with other penicillin-binding proteins suggests that these proteins are not precursors or multimers of the enzyme.