Patient-reported health outcomes of SARS-CoV-2-tested patients presenting to emergency departments: a propensity score-matched prospective cohort study

OBJECTIVE

This study aimed to compare the long-term physical and mental health outcomes of matched severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive and SARS-CoV-2-negative patients controlling for seasonal effects.

STUDY DESIGN

This was a retrospective cohort study.

METHODS

This study enrolled patients presenting to emergency departments participating in the Canadian COVID-19 Emergency Department Rapid Response Network. We enrolled consecutive eligible consenting patients who presented between March 1, 2020, and July 14, 2021, and were tested for SARS-CoV-2. Research assistants randomly selected four site and date-matched SARS-CoV-2-negative controls for every SARS-CoV-2-positive patient and interviewed them at least 30 days after discharge. We used propensity scores to match patients by baseline characteristics and used linear regression to compare Veterans RAND 12-item physical health component score (PCS) and mental health component scores (MCS), with higher scores indicating better self-reported health.

RESULTS

We included 1170 SARS-CoV-2-positive patients and 3716 test-negative controls. The adjusted mean difference for PCS was 0.50 (95% confidence interval [CI]: -0.36, 1.36) and -1.01 (95% CI: -1.91, -0.11) for MCS. Severe disease was strongly associated with worse PCS (β = -7.4; 95% CI: -9.8, -5.1), whereas prior mental health illness was strongly associated with worse MCS (β = -5.4; 95% CI: -6.3, -4.5).

CONCLUSION

Physical health, assessed by PCS, was similar between matched SARS-CoV-2-positive and SARS-CoV-2-negative patients, whereas mental health, assessed by MCS, was worse during a time when the public experienced barriers to care. These results may inform the development and prioritization of support programs for patients.

The contribution of health behaviours to waist circumference change following employment transitions

Background

Mechanisms through which retirement and later-life job loss lead to subsequent weight change are poorly understood, and include changes to one’s health behaviours (HBs) after employment changes. Our study assessed the potential role of HBs in the impact of employment transitions (ET) on waist circumference (WC), by gender.

Methods

We used two waves of survey data from a Canadian sample of 45- to 85-year-olds with objectively measured WC. For 10,117 participants who were working at baseline, we categorized them into three ET statuses: stayed working, entered retirement, and stopped working. Changes in HBs [sleep, smoking, drinking, and physical activity (PA)] were coded by comparing baseline and follow-up responses. Change in WC was analyzed using multivariable linear regression and multinomial logistic regression models (≥5% gain or loss, no change).

Results

Multivariable models showed that the addition of change in HBs did not alter the effect sizes of ETs on WC change. Regardless of ET status, women who quit smoking had an increased WC compared to persistent non-smokers (1.43cm, 95% Confidence Interval 0.07 - 2.79). Women who became habitual drinkers showed more increases in WC compared to non-habitual drinkers (1.43cm, 0.16 - 2.69). Changes to sleep duration were not associated with WC change; however, women who became satisfied with their sleep had greater WC increases compared to already satisfied sleepers (0.79cm, 0.12 - 1.46). Men who increased their PA by > 1hr to 2hrs were less likely to gain ≥5% weight compared to men with no PA change (OR = 0.75, 0.57 - 0.99). Women who increased their PA by > 1hr to 2hrs were less likely to lose ≥5% weight (OR = 0.74, 0.56 - 0.99).

Conclusions

Our study of this Canadian cohort of middle-aged and older adults suggests some HBs are independent risk factors for weight change rather than mechanisms in the employment-anthropometry relationship.

Key messages

• Health behaviour changes in middle-aged and older adults have anthropometric effects that differ by sex/gender, independent of employment transitions.

• Promotion of persistently good sleep quality to women may help maintain waist size.

Expanding the use of dolutegravir-based antiretroviral therapy in multidrug-resistant TB

The wider availability of dolutegravir (DTG) containing HIV therapy for patients living with multidrug-resistant TB (MDR-TB) presents several advantages. DTG-based antiretroviral therapy (ART) has superior potency, reduces pill burden, and may reduce overall treatment-related toxicity, giving it the potential to improve outcomes in both diseases. While the uptake of DTG-based ART in programs where drug-resistant TB is treated remains unknown, there is early evidence from three programs that uptake is increasing. The use of DTG-based ART should be scaled-up, beginning with antiretroviral-naïve or virologically suppressed patients initiating MDR-TB treatment.

Metabolomics and cancer preventive behaviors in the BC Generations Project

Metabolomics can detect metabolic shifts resulting from lifestyle behaviors and may provide insight on the relevance of changes to carcinogenesis. We used non-targeted nuclear magnetic resonance to examine associations between metabolic measures and cancer preventive behaviors in 1319 participants (50% male, mean age 54 years) from the BC Generations Project. Behaviors were dichotomized: BMI < 25 kg/m², ≥ 5 servings of fruits or vegetables/day, ≤ 2 alcoholic drinks/day for men or 1 drink/day for women and ≥ 30 min of moderate or vigorous physical activity/day. Linear regression was used to estimate coefficients and 95% confidence intervals with a false discovery rate (FDR) of 0.10. Of the 218 metabolic measures, 173, 103, 71 and 6 were associated with BMI, fruits and vegetables, alcohol consumption and physical activity. Notable findings included negative associations between glycoprotein acetyls, an inflammation-related metabolite with lower BMI and greater fruit and vegetable consumption, a positive association between polyunsaturated fatty acids and fruit and vegetable consumption and positive associations between high-density lipoprotein subclasses with lower BMI. These findings provide insight into metabolic alterations in the context of cancer prevention and the diverse biological pathways they are involved in. In particular, behaviors related to BMI, fruit and vegetable and alcohol consumption had a large metabolic impact.

Urgent need to improve programmatic management of patients with HIV failing first-line antiretroviral therapy

Introduction

Delayed identification and response to virologic failure in case of first-line antiretroviral therapy (ART) in resource-limited settings is a threat to the health of HIV-infected patients. There is a need for the implementation of an effective, standardized response pathway in the public sector.

Discussion

We evaluated published cohorts describing virologic failure on first-line ART. We focused on gaps in the detection and management of treatment failure, and posited ways to close these gaps, keeping in mind scalability and standardization. Specific shortcomings repeatedly recorded included early loss to follow-up (>20%) after recognized first-line ART virologic failure; frequent delays in confirmatory viral load testing; and excessive time between the confirmation of first-line ART failure and initiation of second-line ART, which exceeded 1 year in some cases. Strategies emphasizing patient tracing, resistance testing, drug concentration monitoring, adherence interventions, and streamlined response pathways for those failing therapy are further discussed.

Conclusion

Comprehensive, evidence-based, clinical operational plans must be devised based on findings from existing research and further tested through implementation science research. Until this standard of evidence is available and implemented, high rates of losses from delays in appropriate switch to second-line ART will remain unacceptably common and a threat to the success of global HIV treatment programs.

Targeting the third '90': introducing the viral load champion

Objective: To move closer to achieving the third target of the UNAIDS 90-90-90 goals, we prospectively implemented a viral load (VL) champion (VLC) program aimed at enhancing VL monitoring and recognition of treatment failure. Design: Three clinics in eThekwini, Kwa-Zulu Natal (low-, medium- and high-volume, encompassing 9184 patients overall) were each assigned a VLC. We employed a descriptive analysis (chart audit) to compare the pre-intervention period to a 1-year post-intervention period. The number of patients with a VL test performed 6 and 12 months after the intervention was calculated as a proportion of VL tests due at those time points (VL completion rate). Results: The pre-implementation VL completion rate at the three sites was respectively 68% (140/205 patients), 54% (84/155 patients) and 64% (323/504 patients), and the 6-month post-implementation completion rate increased to 83% (995/1194 patients), 90% (793/878 patients) and 99% (3101/3124 patients) (P < 0.0001 for each site). VL completion rates remained significantly higher at 12 months post-implementation, with an average cumulative VL completion rate of >90% across all facilities. Conclusion: We demonstrate a successful, multifaceted, quality-improvement intervention centered on a clinic-level VLC which, taken to scale, has important implications for attaining the third UNAIDS 90-90-90 target.

Effect of client complaints on small animal veterinary internists

OBJECTIVES

To investigate the effect of client complaints on small animal veterinary internists' welfare, job satisfaction and medical practices.

MATERIALS AND METHODS

Cross-sectional anonymous survey study. Between February 1 and March 31, 2017, a web-based questionnaire was made available through the American College Veterinary Internal Medicine sub-specialty Small Animal Internal Medicine E-mail List Serve.

RESULTS

A total of 92 completed surveys were available for review. Fifty-nine (64∙1%) respondents received a client complaint during the previous 6 months with cost of care the most common reason (53∙3%). Eighty-nine (96∙7%) respondents worry about client complaints being made against them with 33 (35∙8%) stating they worry "most of the time" or "all of the time." Thirty-two (34∙8%) reported being verbally assaulted by a client in the previous 6 months and 27 (29∙4%) reported being threatened with litigation during the previous 6 months. Sixty-six (71∙7%) have reported changing the way they practice medicine to avoid a client complaint and 40 (43∙5%) have considered changing their career because of complaints made against them.

CLINICAL RELEVANCE

Client complaints are a frequent problem among small animal veterinary internists that have detrimental effects on job satisfaction, psychological distress and medical practices.

Two pathways to causal control: use and availability of information in the environment in people with and without signs of depression

Perceiving one's causal control is important for adaptive behavior. Studying depression and other individual differences has provided insight into typical as well as pathological causal processing. We set out to study factors that have been shown to distinguish those with and without signs of depression and affect perceptions of causal control: levels of behavior, the availability of outcomes and learning about the environment or context. Two experiments were carried out in which participants, scoring low and high on the Beck Depression Inventory using established cutoffs, completed a causal control task, in which outcomes occurred with a low (.25) or high probability (.75). Behavior levels were either constrained (N1=73) or unconstrained (N2=74). Overall, findings showed that levels of behavior influenced people's experiences of the context in which events occurred. For all participants, very high behavior levels eliminated sensitivity to levels of outcomes occurring in the environment and lead to judgments that were consistent with conditional probabilities as opposed to the experimenter programmed contingency. Thus increased behavior increased perceived control via influence on context experience. This effect was also evident for those scoring high on the BDI. Overall conclusions are that behavior and context provide two important interlinked psychological pathways to perceived control. However, situations that constrain people's ability to respond freely can prevent people with signs of depression from taking control of a situation that would otherwise be uncontrollable.

Polyunsaturated fatty acids in relation to incident mobility disability and decline in gait speed; the Age, Gene/Environment Susceptibility-Reykjavik Study

BACKGROUND/OBJECTIVES

Low intake of long chain polyunsaturated fatty acids (PUFAs) are associated with physical disability; however, prospective studies of circulating PUFAs are scarce. We examined associations between plasma phospholipid n-3 and n-6 PUFAs with risk of incident mobility disability and gait speed decline.

SUBJECTS/METHODS

Data are from a subgroup of the Age, Gene/Environment Susceptibility-Reykjavik Study, a population-based study of risk factors for disease and disability in old age. In this subgroup (n = 556, mean age 75.1 ± 5.0 years, 47.5% men), plasma phospholipid PUFAs were assessed at baseline using gas chromatography. Mobility disability and usual gait speed were assessed at baseline and after 5.2 ± 0.2 years. Mobility disability was defined as the following: having much difficulty, or being unable to walk 500 m or climb up 10 steps; decline in gait speed was defined as change ⩾ 0.10 m/s. Logistic regression analyses were performed to determine associations between sex-specific s.d. increments in PUFAs with risk of incident mobility disability and gait speed decline. Odds ratios (95% confidence intervals) adjusted for demographics, follow-up time, risk factors and serum vitamin D were reported.

RESULTS

In women, but not men, every s.d. increment increase of total n-3 PUFAs and docosahexaenoic acid (DHA) was associated with lower mobility disability risk, odds ratio 0.48 (0.25; 0.93) and odds ratio 0.45 (0.24; 0.83), respectively. There was no association between n-6 PUFAs and the risk of incident mobility disability or gait speed decline.

CONCLUSIONS

Higher concentrations of n-3 PUFAs and, particularly, DHA may protect women from impaired mobility but does not appear to have such an effect in men.

Operationalizing early antiretroviral therapy in HIV-infected in-patients with opportunistic infections including tuberculosis

BACKGROUND

We describe the outcomes of a program in which antiretroviral therapy (ART) is offered to human immunodeficiency virus (HIV) infected patients in South Africa admitted with tuberculosis (TB) or other opportunistic infection (OI) as part of in-patient care.

METHODS

Patients admitted with HIV and concurrent TB or other OI were initiated on early in-patient ART. The primary and secondary endpoints were respectively 24-week mortality and 24-week virologic suppression. Multivariable logistic regression modeling explored the associations between baseline (i.e., pre-hospital discharge) characteristics and mortality at 24 weeks.

RESULTS

A total of 382 patients were prospectively enrolled (48% women, median age 37 years, median CD4 count 33 cells/mm(3)). Acute OIs were pulmonary TB, 39%; extra-pulmonary TB, 25%; cryptococcal meningitis (CM), 10%; and chronic diarrhea, 9%. The median time from admission to ART initiation was 14 days (range 4-32, IQR 11-18). At 24 weeks of follow-up, as-treated and intention-to-treat virologic suppression were respectively 57% and 93%. Median change in CD4 cell count was +100 cells/mm(3), overall 24-week mortality was 25% and loss to follow-up, 5%. Excess mortality was not observed among patients with CM who initiated early ART. A longer interval between admission and ART was associated with mortality (>21 days vs. <21 days after admission OR 2.1, 95%CI 1.2-4.0, P = 0.016).

CONCLUSIONS

For HIV-infected in-patients with TB or an acquired immune-deficiency syndrome defining OI, we demonstrate the operational feasibility of early ART initiation in in-patients.

Effect of dietary prebiotic (mannan oligosaccharide) supplementation on the caecal bacterial community structure of turkeys

The identification of specific bacterial species influenced by mannan oligosaccharide (MOS) supplementation may assist in the formulation of new and improved diets that promote intestinal health and improve bird performance, offering suitable alternatives to antimicrobials in feed for sustainable poultry production. This study has been conducted to evaluate the use of a MOS compound derived from the yeast cell wall of Saccharomyces cerevisiae on turkey performance, bacterial community structure and their phylogenetic associations. A 42-day turkey trial was carried out on birds fed control and MOS-supplemented diets. Bird performance data (weight gains, feed consumption and feed efficiency ratios) were collected, and caecal contents were extracted from randomly caught poults on days 28, 35 and 42 posthatch. Bird performance data showed no improvements as a result of dietary supplementation. Automated ribosomal intergenic spacer analysis (ARISA) revealed the bacterial community structure to be significantly altered on days 28 and 35 posthatch but not day 42 as a result of dietary supplementation. This technique was coupled with 16S rRNA gene sequence analysis to elucidate phylogenetic identities of bacteria. The dominant bacteria of the caecum on all days in both treatment groups were members of phylum Firmicutes, followed by the Bacteroidetes and Proteobacteria phyla, respectively. Statistical analysis of the 16S rRNA gene libraries showed that the composition of the MOS clone library differed significantly to the control on day 35 posthatch. It can be concluded that MOS alters the bacterial community structure in the turkey caecum.

Influence of eicosapentaenoic acid supplementation on lean body mass in cancer cachexia

Cancer cachexia is characterised by a progressive loss of muscle, resulting in functional impairment and shorter survival. Eicosapentaenoic acid, an n-3 polyunsaturated fatty acid found in fish, has been studied for its role as an anti-cachexia therapy. Initial results of eicosapentaenoic supplementation in advanced cancer were promising with improvements in lean body mass (LBM), appetite and quality of life. However, subsequent larger phase III clinical trials reported minimal benefits of supplementation. Recently, several studies have used different study designs, which may provide insight on the effectiveness of eicosapentaenoic in cancer cachexia and also on potential sources of divergent results in previous trials. This review examines the potential benefit of eicosapentaenoic supplementation on LBM and discusses limitations with current studies to identify methods which may aid in progressing the research of future clinical trials.

Vanadium Dioxide Films Grown from Vanadium Tetrakis(t-Butoxide) by the Sol-Gel Process

Vanadium dioxide thin films have been grown from vanadium tetrakis (t-butoxide) by the sol-gel process. A new method for the synthesis of the vanadium precursor was developed. Films were deposited by dipcoating glass slides from an isopropanol solution, followed by post-deposition annealing of the films at 600 °C under nitrogen. The properties of these films, to a high degree, were a function of the preparation conditions. These gel-derived VO2 films undergo a reversible semiconductor-to-metal phase transition near 72 °C, exhibiting characteristic resistive and spectral switching comparable with near stoichiometric VO2 films prepared on non-crystalline substrates by other techniques. Paralleling the investigation of pure VO2, films were doped with hexavalent transition metal oxides to demonstrate lowering of the transition temperature.

Low uptake of antiretroviral therapy after admission with human immunodeficiency virus and tuberculosis in KwaZulu-Natal, South Africa

OBJECTIVES

A prospective cohort study was conducted among human immunodeficiency virus (HIV) infected in-patients with tuberculosis (TB) or other opportunistic infections (OIs) in South Africa to estimate subsequent antiretroviral therapy (ART) uptake and survival.

METHODS

Logistic regression modeling explored associations between baseline characteristics and starting ART, and ART exposure-adjusted incidence of death was estimated over 6 months of follow-up.

RESULTS

Among 49 participants enrolled, median CD4 cell count at hospital discharge was 42 cells/microl and the most common presenting OIs were TB (76%), Pneumocystis pneumonia (8%), chronic diarrhea (8%), cryptococcal meningitis (6%), and Toxoplasma gondii (4%). By 6 months, only 20 (45%) patients had initiated ART, and four (8%) were lost to follow-up. ART uptake was independently associated with previous use of traditional medicine (OR 7.2, 95%CI 1.4-55.1) and with less advanced HIV infection (baseline CD4 count per 50 cells/microl increase OR 1.4, 95%CI 0.9-2.2). A total of 14 (31%) patients died before initiating ART; the monthly incidence of death did not decrease over the 6-month interval.

CONCLUSION

The high mortality observed within the 6 months following hospitalization with TB or other acute OIs indicate that mechanisms are needed to expedite ART for patients after an acquired immune-deficiency syndrome defining illness.

Quantification of supplemental enzymes in animal feedingstuffs by radial enzyme diffusion

Methods are described which facilitate quantification of supplemental cellulase, protease and alpha-amylase when added to animal feedingstuffs at normal industrial inclusion levels. The methods entail extraction of the enzymes from the feedingstuffs by agitation in buffer followed by quantification of extract activity using radial diffusion techniques. A linear relationship between the diameter of the zone of hydrolyzed substrate and the log of the enzyme activity applied is observed over a broad activity range. Assay of a feedingstuff supplemented with 1 kg t(-1) cellulase, protease and alpha-amylase yielded net supplemental activity recoveries of 104+/-11.7%, 91.3+/-6.74% and 126+/-29.5%, respectively. A similar assay method did not prove sufficiently sensitive to facilitate detection of xylanase at typical in-feed inclusion levels. The levels of endogenous cellulase, protease and alpha-amylase activity detected in the unsupplemented feedingstuffs were equivalent to 6.4+/-0.47%, 6.6+/-0.82% and 29.0+/-14.1%, respectively, of a 1 kg t(-1) supplement. The methods are technically straightforward and will facilitate determination of enzyme stabilities during processes such as high-temperature pelleting of feedingstuffs, as well as allowing more rigorous quality control related to enzyme-supplemented animal feedingstuffs.

Expression of an alpha-galactosidase from Saccharomyces cerevisiae in Aspergillus awamori and Aspergillus oryzae

A gene encoding alpha-galactosidase activity was isolated by polymerase chain reaction (PCR) from Saccharomyces cerevisiae NCYC686 and separately placed under the control of transcriptional elements regulating alpha-amylase expression in Aspergillus oryzae and glucoamylase expression in A. awamori. Following transformation of both A. oryzae and A. awamori with their respective expression vectors, induction of heterologous alpha-galactosidase from positively selected clones was effected through the addition of soluble starch (10% wt/vol) to the growth medium. Upon induction in A. oryzae, a transcriptional instability resulted in degradation of mRNA encoding heterologous alpha-galactosidase, thus preventing expression of the active enzyme. The use of a gene fusion strategy in A. awamori overcame this instability and resulted in stable expression of S. cerevisiae alpha-galactosidase. Subsequent to initial (shake flask) experiments, a series of scale-up and optimisation studies led to heterologous expression of the recombinant enzyme in batch fermentation at 51 U mg(-1) total extracellular protein. This was higher than previously published works, which reported extracellular levels of heterologous alpha-galactosidase up to 38 U mg(-1) total protein. Analysis of crude extracts of the fermentation medium revealed significant differences between the activity parameters reported previously in the literature for this enzyme and those observed here. The recombinant enzyme exhibited thermostability properties not previously reported for S. cerevisiae alpha-galactosidase, a trait which would make it suitable for use in processes requiring high temperatures.

Cross-bridge regulation by Ca(2+)-dependent phosphorylation in amphibian smooth muscle

A covalent regulatory mechanism involving Ca(2+)-dependent cross-bridge phosphorylation determines both the number of cycling cross bridges and cycling kinetics in mammalian smooth muscle. Our objective was to determine whether a similar regulatory mechanism governed smooth muscle contraction from a poikilothermic amphibian in a test of the hypothesis that myosin regulatory light chain (MRLC) phosphorylation could modulate shortening velocity. We measured MRLC phosphorylation of Rana catesbiana urinary bladder strips at 25 degrees C in tonic contractions in response to K+ depolarization, field stimulation, or carbachol stimulation. The force-length relationship was characterized by a steep ascending limb and a shallow descending limb. There was a rapid rise in unloaded shortening velocity early in a contraction, which then fell and was maintained at low rates while high force was maintained. In support of the hypothesis, we found a positive correlation of the level of myosin phosphorylation and an estimate of tissue shortening velocity. These results suggest that MRLC phosphorylation in amphibian smooth muscle modulates both the number of attached cross bridges (force) and the cross-bridge cycling kinetics (shortening velocity) as in mammalian smooth muscle.

Activation of myosin light chain phosphatase in intact arterial smooth muscle during nitric oxide-induced relaxation

We investigated whether myosin light chain phosphatase activity changes during nitric oxide-induced relaxation of contracted intact carotid media and how changes in phosphatase activity mediate this relaxation. We also investigated one mechanism for regulating this phosphatase. Myosin phosphatase activity, myosin light chain phosphorylation, guanosine 3',5'-cyclic monophosphate (cGMP) concentration, and phosphorylation of the inhibitory protein CPI-17 were all assayed in homogenates of one carotid media ring at each time point during nitric oxide-induced relaxation. The application of sodium nitroprusside to histamine-contracted media caused rapid declines in light chain phosphorylation and force. These were temporally correlated with a rapid elevation of cGMP and a large transient increase in myosin phosphatase activity. During the early response to nitroprusside, when force declined, increases in myosin phosphatase activity, concurrent with cGMP-mediated decreases in calcium and myosin light chain kinase activity, could accelerate light chain dephosphorylation. CPI-17 was dephosphorylated upon application of nitroprusside at the same time that myosin phosphatase activity increased, suggesting that the removal of inhibition by phospho-CPI-17 contributed to the increase in myosin phosphatase activity. After 20 min of nitroprusside, myosin phosphatase activity had declined to basal levels, however low force was sustained. Additional light chain phosphorylation-independent mechanisms may be involved in sustaining the relaxation.

Selected contribution: HSP20 phosphorylation in nitroglycerin- and forskolin-induced sustained reductions in swine carotid media tone

Cyclic nucleotide-induced relaxation of maximally activated arterial smooth muscle has two phases. 1) The initial relaxation transient is typically characterized by a rapid reduction in force associated with brief reductions in myoplasmic Ca(2+) concentration ([Ca(2+)](i)) and myosin regulatory light chain (MRLC) phosphorylation on serine (Ser)-19 (Ser(19)). 2) The sustained inhibitory response is typically associated with Ser(16) phosphorylation of heat shock protein 20 (HSP20) without sustained reductions in [Ca(2+)](i) or MRLC phosphorylation. We investigated whether the extent of Ser(16)-HSP20 phosphorylation quantitatively correlated with the sustained inhibitory response. With addition of nitroglycerin to histamine-stimulated swine carotid media, the initial relaxation transient was associated with a decrease in MRLC phosphorylation without an increase in Ser(16)-HSP20 phosphorylation. During the sustained phase of nitroglycerin-induced relaxation and during force redevelopment induced by washout of nitroglycerin in the continued presence of histamine, the level of Ser(16)-HSP20 phosphorylation, but not MRLC phosphorylation, correlated with inhibition of force. Forskolin, which increases cAMP concentration, also induced a sustained inhibitory response that was associated with increases in Ser(16)-HSP20 phosphorylation without reductions in MRLC phosphorylation levels. Forskolin increased Ser(16)-HSP20 phosphorylation to a greater extent and inhibited force more completely than that observed with nitroglycerin. Increases in Ser(16)-HSP20 phosphorylation correlated with the degree of force inhibition regardless of whether the relaxation was induced by nitroglycerin or forskolin. These data are consistent with the hypothesis that Ser(16)-HSP20 phosphorylation may be a cyclic nucleotide-dependent, yet MRLC phosphorylation-independent, inhibitor of smooth muscle contractile force.