Enhancing VSV oncolytic activity with an improved cytosine deaminase suicide gene strategy

Oncolytic viruses (OVs) are promising therapeutic agents for cancer treatment, with recent studies emphasizing the combined use of chemotherapeutic compounds and prodrug suicide gene strategies to improve OV efficacy. In the present study, the synergistic activity of recombinant vesicular stomatitis virus (VSV)-MΔ51 virus expressing the cytosine deaminase/uracil phosphoribosyltransferase (CD::UPRT) suicide gene and 5-fluorocytosine (5FC) prodrug was investigated in triggering tumor cell oncolysis. In a panel of VSV-sensitive and -resistant cells-prostate PC3, breast MCF7 and TSA, B-lymphoma Karpas and melanoma B16-F10-the combination treatment increased killing of non-infected bystander cells in vitro via the release of 5FC toxic derivatives. In addition, we showed a synergistic effect on cancer cell killing with VSV-MΔ51 and the active form of the drug 5-fluorouracil. Furthermore, by monitoring VSV replication at the tumor site and maximizing 5FC bioavailability, we optimized the treatment regimen and improved survival of animals bearing TSA mammary adenocarcinoma. Altogether, this study emphasizes the potency of the VSV-CD::UPRT and 5FC combination, and demonstrates the necessity of optimizing each step of a multicomponent therapy to design efficient treatment.

Implementation and effectiveness of a community-based health promotion program for older adults

BACKGROUND

Because preventing functional decline in older adults is a national priority and senior centers have been identified as potentially important venues for health-promotion activities, a trial of a multicomponent disability prevention program was conducted at a senior center.

METHODS

One hundred older adults were recruited for a 6-month randomized clinical trial. All members of the experimental group received an exercise intervention, nutrition counseling, and a home safety assessment. Smoking and alcohol interventions were delivered to at-risk subjects. Outcome variables included the Medical Outcomes Study Short Form (SF-36) health survey, the CES-Depression scale, bed days, and restricted-activity days.

RESULTS

A single study announcement resulted in a response sufficient to recruit 100 subjects. The exercise program was well received: 85% of intervention subjects completed the 6-month program and adherence was excellent, with over 90% attendance at exercise classes. After 6 months the intervention group had significantly better scores on 7 of 8 SF-36 subscales and fewer depressive symptoms than controls.

CONCLUSIONS

Senior centers may be excellent sites for community-based health promotion interventions: participation and adherence rates may be acceptable, interventions can be designed that are feasible in this setting, and these interventions appear to affect health status positively. The study program improved physical and psychosocial functioning and is a promising model for preventing functional decline through activities based at senior centers.

Severity of upper and lower extremity functional limitation: scale development and validation with self-report and performance-based measures of physical function. WHAS Research Group. Women's Health and Aging Study

OBJECTIVES

To better understand disablement and transitions from impairment to disability, discrete valid measures of functional limitation are needed. This study reports the development and criterion-related validity of scales that quantify severity of upper and lower extremity functional limitation.

METHODS

Data are from 3,635 cognitively intact community-dwelling women aged 65 years and older and 1,002 moderately to severely disabled participants in the Women's Health and Aging Study. Scales assessing severity of upper and lower extremity functional limitation were constructed from commonly available questions on functional difficulty. Criterion-related validity was evaluated with self-report and performance-based measures.

RESULTS

The upper and lower extremity scales range from 0 to 6 and 0 to 9, respectively. Scale scores were well distributed in the disabled group and discriminated limitations in the broader community. For both scales, rates of difficulty for all ADL and IADL increased (p<.001) with increasing severity score, and percent able and mean performance on respective upper and lower extremity tasks decreased (p<.01).

DISCUSSION

These scales, constructed from commonly used self-report measures of function, provide discrete measures of upper and lower functional limitation. Because these scales are distinct from measures of disability and impairment, their use should facilitate increased understanding of the disablement process.

Coimpairments as predictors of severe walking disability in older women

OBJECTIVE

Severe disabilities are common among older people who have impairments in a range of physiologic systems. It is not known, however, whether the presence of multiple impairments, or coimpairments, is associated with increased risk of developing new disability. The aim of this study was to determine the combined effects of two impairments, decreased knee-extension strength and poor standing balance, on the risk of developing severe walking disability among older, moderately-to-severely disabled women who did not have severe walking disability at baseline.

DESIGN

The Women's Health and Aging Study is a 3-year prospective study with 6 semi-annual follow-up data-collection rounds following the baseline.

SETTING

At baseline, knee-extension strength and standing balance tests took place in the participants' homes.

PARTICIPANTS

758 women who were not severely walking disabled at baseline.

MEASUREMENTS

Severe walking disability was defined as customary walking speed of < 0.4 meters/second and inability to walk one quarter of a mile, or being unable to walk.

RESULTS

Over the course of the study, 173 women became severely disabled in walking. The cumulative incidence of severe walking disability from the first to the sixth follow-up was: 7.8%, 12.0%, 15.1% 19.5% 21.2%, and 22.8%. In Cox proportional hazards models, both strength and balance were significant predictors of new walking disability. In the best balance category, the rates of developing severe walking disability expressed per 100 person years were 3.1, 6.1, and 5.3 in the highest- to lowest-strength tertiles. In the middle balance category, the rates were 9.6, 13.2, and 14.7, and in the poorest balance category 21.6, 12.7, and 37.1, correspondingly. The relative risk (RR) of onset of severe walking disability adjusted for age, height, weight, and race was more than five times greater in the group with poorest balance and strength (RR 5.12, 95% confidence limit [95% CI] 2.68-9.80) compared with the group with best balance and strength (the reference group). Among those who had poorest balance and best strength, the RR of severe walking disability was 3.08 (95% CI 1.33-7.14). Among those with best balance and poorest strength, the RR was 0.97 (95% CI 0.49-1.93), as compared with the reference group.

CONCLUSION

The presence of coimpairments is a powerful predictor of new, severe walking disability, an underlying cause of dependence in older people. Substantial reduction in the risk of walking disability could be achieved even if interventions were successful in correcting only one of the impairments because a deficit in only one physiologic system may be compensated for by good capacity in another system.

Exploring the effect of depression on physical disability: longitudinal evidence from the established populations for epidemiologic studies of the elderly

OBJECTIVES

This study examined the effect of depression on the incidence of physical disability and the role of confounding and explanatory variables in this relationship.

METHODS

A cohort of 6247 subjects 65 years and older who were initially free of disability was followed up for 6 years. Baseline depression was assessed by the Center for Epidemiological Studies Depression Scale. Disability in mobility and disability in activities of daily living were measured annually.

RESULTS

Compared with the 5751 nondepressed subjects, the 496 depressed subjects had a relative risk (95% confidence interval) of 1.67 (1.44, 1.95) and 1.73 (1.54, 1.94) for incident disability in activities of daily living and mobility, respectively. Adjustment for sociodemographic characteristics and baseline chronic conditions reduced the risks to 1.39 (1.18, 1.63) and 1.45 (1.29, 1.93), respectively. Less physical activity and fewer social contacts among depressed persons further explained part of their increased disability risk.

CONCLUSIONS

Depression in older persons may increase the risk for incident disability. This excess risk is partly explained by depressed persons' decreased physical activity and social interaction. The role of other factors (e.g., biological mechanisms) should be examined.

Characteristics and behaviours associated with difficulty in performing activities of daily living among older New Zealand women

PURPOSE

The objective of this cross-sectional study was to determine the prevalence of self-reported difficulty in performing activities of daily living (ADLs) and the associated characteristics and behaviours among older women in Auckland, New Zealand.

METHODS

A sample of 569 community dwelling women aged 65 years and older were studied. Logistic regression was used to calculate odds ratios and 95% confidence intervals for the association of participant characteristics and behaviours with reported difficulty in performing > or = 1 of five basic ADLs.

RESULTS

An age adjusted prevalence of 4.6% was found for reported ADL difficulty. Age > or = 85 years (odds ratio [OR] 5.9; 95% confidence interval [CI] 1.1-30.2), history of stroke (OR 9.8; 95% CI 4.1-23.3), history of > or = 1 fall in the past year (OR 3.4; 95% CI 1.6-7.4), low body mass index (OR 2.8; 95% CI 1.2-6.4), and low grip strength (OR 2.6; 95% CI 1.2-5.5) were significantly and independently associated with ADL difficulty. Among women with ADL difficulty, the prevalence of adaptive equipment use was high (> 90%).

CONCLUSIONS

Several characteristics, medical conditions, and behaviours, some of which may be preventable, are associated with physical disability in older New Zealand women. Studies like this are an important step toward the development of interventions to reduce or delay disability and improve health and quality of life.

Coimpairments: strength and balance as predictors of severe walking disability

BACKGROUND

Little information is available on the joint effects of multiple impairments (coimpairments) on the risk of disability. Our aim was to study the joint effects of strength and balance impairments on severe walking disability.

METHODS

The data are from the baseline of the Women's Health and Aging Study (WHAS), a study of moderately to severely disabled women. A total of 1,002 women aged 65 and older participated in the tests, which took place in their homes. Severe walking disability was defined as self-reported inability to walk one-quarter mile and customary walking speed in a 4-meter test of < or =0.4 m/s. Balance was measured as an ability to hold progressively more difficult stands (feet side-by-side, semitandem and tandem stands). Maximal knee extension strength was measured using a hand-held dynamometer.

RESULTS

There were 129 women who were severely walking disabled but able to walk at least minimally. In logistic regression analysis, balance and knee extension strength were independent predictors of severe walking disability. To study the combined effects, nine groups were formed on the basis of strength tertiles by balance categories in the entire population. In the best balance category, the crude prevalences of severe walking disability were 1.2%, 4.9%, and 14.3% in the highest to lowest strength tertiles. In the middle balance category, the rates were 2.9%, 10.0%, and 45.4.1%, and in the poorest balance category 4.9%, 22.1%, and 42.6%, correspondingly. The age, body weight, and height-adjusted odds ratios (OR) showed that the risk of severe walking disability in the subgroup with best balance and strength was less than 5% of the risk in the subgroup with poorest balance and strength (OR .034, 95% confidence interval [CI] .007-.166). Correspondingly, in the subgroups with poorest strength and best balance (OR .097, 95% CI .025-.38) or poorest balance and best strength (OR .102, 95% CI .012-.866) the risk was about 10%. The age-specific estimates of prevalence of severe walking disability in women were: 2.0% for ages 65-74 years, 3.4% for ages 75-84 years, and 9.1% for ages 85 years and older.

CONCLUSIONS

The burden of coimpairments seems to be greater than the sum of single impairments involved. An effective way to reduce severe disabilities could be prevention of coimpairments.

Smoking, physical activity, and active life expectancy

The effect of smoking and physical activity on active and disabled life expectancy was estimated using data from the Established Populations for Epidemiologic Studies of the Elderly (EPESE). Population-based samples of persons aged > or = 65 years from the East Boston, Massachusetts, New Haven, Connecticut, and Iowa sites of the EPESE were assessed at baseline between 1981 and 1983 and followed for mortality and disability over six annual follow-ups. A total of 8,604 persons without disability at baseline were classified as "ever" or "never" smokers and doing "low," "moderate," or "high" level physical activity. Active and disabled life expectancies were estimated using a Markov chain model. Compared with smokers, men and women nonsmokers survived 1.6-3.9 and 1.6-3.6 years longer, respectively, depending on level of physical activity. When smokers were disabled and close to death, most nonsmokers were still nondisabled. Physical activity, from low to moderate to high, was significantly associated with more years of life expectancy in both smokers (9.5, 10.5, 12.9 years in men and 11.1, 12.6, 15.3 years in women at age 65) and nonsmokers (11.0, 14.4, 16.2 years in men and 12.7, 16.2, 18.4 years in women at age 65). Higher physical activity was associated with fewer years of disability prior to death. These findings provide strong and explicit evidence that refraining from smoking and doing regular physical activity predict a long and healthy life.

Midlife hand grip strength as a predictor of old age disability

CONTEXT

Poor muscle strength, functional limitations, and disability often coexist, but whether muscle strength during midlife predicts old age functional ability is not known.

OBJECTIVE

To determine whether hand grip strength measured during midlife predicts old age functional limitations and disability in initially healthy men.

DESIGN AND SETTING

A 25-year prospective cohort study, the Honolulu Heart Program, which began in 1965 among Japanese-American men living on Oahu, Hawaii.

PARTICIPANTS

A total of 608945- to 68-year-old men who were healthy at baseline and whose maximal hand grip strength was measured from 1965 through 1970. Altogether, 2259 men died over the follow-up period and 3218 survivors participated in the disability assessment in 1991 through 1993.

MAIN OUTCOME MEASURES

Functional limitations including slow customary walking speed (< or =0.4 m/s) and inability to rise from a seated position without using the arms, and multiple self-reported upper extremity, mobility, and self-care disability outcomes.

RESULTS

After adjustment for multiple potential confounders, risk of functional limitations and disability 25 years later increased as baseline hand grip strength, divided into tertiles, declined. The odds ratio (OR) of walking speed of 0.4 m/s or slower was 2.87 (95% confidence interval [CI], 1.76-4.67) in those in the lowest third and 1.79 (95% CI, 1.14-2.81) in the middle third of grip strength vs those in the highest third. The risk of self-care disability was more than 2 times greater in the lowest vs the highest grip strength tertile. Adding chronic conditions identified at follow-up to the models predicting disability reduced the ORs related to grip strength only minimally.

CONCLUSIONS

Among healthy 45- to 68-year-old men, hand grip strength was highly predictive of functional limitations and disability 25 years later. Good muscle strength in midlife may protect people from old age disability by providing a greater safety margin above the threshold of disability.

Disability, physical activity, and muscle strength in older women: the Women's Health and Aging Study

OBJECTIVE

To study associations of motor disability, physical activity, and muscle strength in older women, in particular to investigate whether model of spiraling decrease is expressed in the data.

DESIGN

Cross-sectional analysis using data from the baseline measurements of The Women's Health and Aging Study (WHAS).

SETTING

Participants' homes.

PARTICIPANTS

A total of 1,002 disabled women aged 65 years and older living in the community.

OUTCOME MEASURES

Motor disability was measured by the number of self-reported difficulties in grasping, lifting 101b, walking across a small room, walking 1/4 mile, climbing 10 steps, and doing heavy housework. Level of physical activity was determined from response to a series of questions on the frequency and amount of common activities and physical exercise. Hand grip and knee extension forces were measured using portable hand-held dynamometers.

RESULTS

Disability and physical activity were inversely associated, with inactivity being most common among the most disabled women. Those with poorer strength reported more difficulties in motor activities. Greater strength was found among the physically more active. In stratified analyses, the positive association of physical activity on knee extension strength was consistent across disability levels. Multiple regression analysis showed that both physical activity and muscle strength were significant predictors for severity of disability. Structural equation model (LISREL) showed that muscle strength had a mediating role between physical activity and disability; disability was associated with physical inactivity, which correlated with lower muscle strength, which was associated with greater degree of disability.

CONCLUSION

Even though causality cannot be confirmed in this cross-sectional analysis, our findings suggested a spiraling model of decline in which muscle strength has a significant role.

Benefits to volunteers in a community-based health promotion and chronic illness self-management program for the elderly

1. Volunteers for health promotion programs tend to be younger and healthier than program participants. 2. Volunteers in a health promotion program reported improved health and function. 3. Nurses involved in health promotion programs can extend their efforts by using trained volunteers.

Racial differences in muscle strength in disabled older women

This study examines racial differences in muscle strength, and associations of muscle strength to level of physical activity and severity of disability, among a community sample of 254 black and 665 white, moderately to severely disabled women aged 65 and older. Potential confounders that were adjusted for in the models included age, body weight and height, joint pain, number of chronic conditions, and socioeconomic status. Hand grip, hip flexion, and knee extension forces were measured using portable hand-held dynamometers in the participants' homes. Hand grip strength was measured as the maximal isometric force. Hip flexion and knee extension forces were measured as the greatest force the tester had to apply to break the isometric contraction. A declining strength gradient was observed with increasing severity of disability and for decreasing level of physical activity in both races. At equal levels of disability or physical activity, blacks had better hand grip and hip flexion strength, but knee extension strength did not differ by race. The greater hand grip and hip flexion strength found in black women may be related to their greater muscle mass and known racial differences in body dimensions. No consistent racial differences were observed in the relationship between physical activity and muscle strength, or muscle strength and disability, suggesting that the role of muscle strength in the disablement process does not differ between races. Physical activity and exercise programs may be feasible ways to prevent worsening of disability in blacks and whites.

1,25-Dihydroxyvitamin D3 and muscle strength in the elderly: a randomized controlled trial

An unexplained loss of muscle strength occurs with aging. Vitamin D deficiency can cause myopathy and administration of 1,25-dihydroxyvitamin D3 [1,25-(OH2)D3] to persons with low serum concentrations can improve strength. To test the hypothesis that the weakness associated with aging is in part due to inadequate serum concentrations of [1,25-(OH2)D3], we conducted a randomized, controlled, double blinded trial in 98 men and women volunteers over 69 yr old. Treatment consisted of 0.25 micrograms 1,25-(OH)2D3, orally, twice per day or identical placebo for 6 months. Leg muscle strength of the quadriceps was measured with an isokinetic dynamometer. There was no difference between the two groups at 1 week, 1 month, or 6 months of treatment in any of the measures of muscle strength. We conclude that oral administration of 0.5 micrograms 1,25-(OH)2D3/day does not improve muscle strength in older persons. Further research is needed to determine the etiology of the decline in muscle strength associated with aging.