Diabetes mellitus does not alter mortality or hospitalisation risk in patients with newly diagnosed heart failure with preserved ejection fraction: Time to rethink pathophysiological models of disease progression

INTRODUCTION

Type 2 diabetes is a common and adverse prognostic co-morbidity for patients with heart failure with reduced ejection fraction (HFrEF). The effect of diabetes on long-term outcomes for heart failure with preserved ejection fraction (HFpEF) is less established.

METHODS

Prospective cohort study of patients referred to a regional HF clinic with newly diagnosed with HFrEF and HFpEF according to the 2016 European Society of Cardiology guidelines. The association between diabetes, all-cause mortality and hospitalisation was quantified using Kaplan-Meier or Cox regression analysis.

RESULTS

Between 1st May 2012 and 1st May 2013, of 960 unselected consecutive patients referred with suspected HF, 464 and 314 patients met the criteria for HFpEF and HFrEF respectively. Within HFpEF and HFrEF groups, patients with diabetes were more frequently male and in both groups patients with diabetes were more likely to be treated with β-adrenoceptor antagonists and angiotensin converting enzyme inhibitors. After adjustment for age, sex, medical therapy and co-morbidities, diabetes was associated with increased mortality in individuals with HFrEF (HR 1.46 95% CI: 1.05-2.02; p = .023), but not in those with HFpEF (HR 1.26 95% CI 0.92-1.72; p = .146).

CONCLUSION

In unselected patients with newly diagnosed HF, diabetes is not an adverse prognostic marker in patients with HFpEF, but is in HFrEF.

Atrial secondary mitral regurgitation: prevalence, characteristics, management, and long-term outcomes

BACKGROUND

The prevalence, clinical characteristics, management and long-term outcomes of patients with atrial secondary mitral regurgitation (ASMR) are not well described.

METHODS

We performed a retrospective, observational study of consecutive patients with grade III/IV MR determined by transthoracic echocardiography. The aetiology of MR was grouped as being either primary (due to degenerative mitral valve disease), ventricular SMR (VSMR: due to left ventricular dilatation/dysfunction), ASMR (due to LA dilatation), or other.

RESULTS

A total of 388 individuals were identified who had grade III/IV MR; of whom 37 (9.5%) had ASMR, 113 (29.1%) had VSMR, 193 had primary MR (49.7%), and 45 (11.6%) were classified as having other causes. Compared to MR of other subtypes, patients with ASMR were on average older (median age 82 [74-87] years, p < 0.001), were more likely to be female (67.6%, p = 0.004) and usually had atrial fibrillation (83.8%, p = 0.001). All-cause mortality was highest in patients with ASMR (p < 0.001), but similar to that in patients with VSMR once adjusted for age and sex (hazard ratio [HR] 0.81, 95% confidence interval [CI] 0.52-1.25). Hospitalisation for worsening heart failure was more commonly observed in those with ASMR or VSMR (p < 0.001) although was similar between these groups when age and sex were accounted for (HR 0.74, 95% CI 0.34-1.58). For patients with ASMR, the only variables associated with outcomes were age and co-morbidities.

CONCLUSIONS

ASMR is a prevalent and distinct disease process associated with a poor prognosis, with much of this related to older age and co-morbidities.

Guideline-directed medical therapy is similarly effective in heart failure with mildly reduced ejection fraction

AIMS

Current guidelines recommend that disease-modifying pharmacological therapies may be considered for patients who have heart failure with mildly reduced ejection fraction (HFmrEF). We aimed to describe the characteristics, outcomes, provision of pharmacological therapies and dose-related associations with mortality risk in HFmrEF.

METHODS AND RESULTS

We explored data from two prospective observational studies, which permitted the examination of the effects of pharmacological therapies across a broad spectrum of left ventricular ejection fraction (LVEF). The combined dataset consisted of 2388 unique patients, with a mean age of 73.7 ± 13.2 years of whom 1525 (63.9%) were male. LVEF ranged from 5 to 71% (mean 37.2 ± 12.8%) and 1504 (63.0%) were categorised as having reduced ejection fraction (HFrEF), 421 (17.6%) as HFmrEF and 463 (19.4%) as preserved ejection fraction (HFpEF). Patients with HFmrEF more closely resembled HFrEF than HFpEF. Adjusted all-cause mortality risk was lower in HFmrEF (hazard ratio [HR] 0.86 (95% confidence interval [CI] 0.74-0.99); p = 0.040) and in HFpEF (HR 0.61 (95% CI 0.52-0.71); p < 0.001) compared to HFrEF. Adjusted all-cause mortality risk was lower in patients with HFrEF and HFmrEF who received the highest doses of beta-blockers or renin-angiotensin inhibitors. These associations were not evident in HFpEF. Once adjusted for relevant confounders, each mg equivalent of bisoprolol (HR 0.95 [95% CI 0.91-1.00]; p = 0.047) and ramipril (HR 0.95 [95%CI 0.90-1.00]; p = 0.044) was associated with incremental reductions in mortality risk in patients with HFmrEF.

CONCLUSIONS

Pharmacological therapies were associated with lower mortality risk in HFmrEF, supporting guideline recommendations which extend the indications of these agents to all patients with LVEF < 50%. HFmrEF more closely resembles HFrEF in terms of clinical characteristics and outcomes. Pharmacological therapies are associated with lower mortality risk in HFmrEF and HFrEF, but not in HFpEF.

Left ventricular dysfunction, heart failure, and mortality risk factors in de novo pacemaker recipients and those requiring pacemaker generator replacement

Background

Pacing the right ventricle (RV) can lead to adverse remodelling of the left ventricle (LV), LV dysfunction, increased risk of heart failure hospitalisation (HFH) and mortality. Despite RV pacing avoidance programming becoming commonplace, pacemaker patients remain at risk of pacing-induced cardiomyopathy. New pacing strategies and cardiac resynchronisation therapy are available therapeutic options, but it is unclear which patients should be targeted, and when.

Purpose

This study examined the effects of RV pacing on LV function, the risk of heart failure requiring hospitalisation and all-cause mortality in patients during the first 12 months of pacemaker therapy, compared to those at pacemaker generator replacement (PGR).

Methods

Data were obtained from a cohort of patients who underwent de novo pacemaker implantation between 2014 and 2017, and patients requiring PGR between 2008 and 2011 at a single tertiary UK hospital, with follow-up from 12 months. Clinical, echocardiographic, and pacemaker variables, medication, and past medical history data were collected. Predictors of a combined endpoint of all-cause mortality or HFH were assessed using cox-regression analysis, with predictors of impaired LV function analysed using multivariable regression analysis.

Results

514 newly implanted (NI) patients (mean age, 75 years; 66% male) were recruited, and 491 patients (mean age, 76 years; 56% male) requiring PGR. After a mean follow up of 887 days, 79 NI patients (16%) were deceased (n=27) or had been hospitalised for HF (n=52), whereas after a mean follow up of 668 days, 56 patients after PGR (12%) were deceased (n=34) or had been hospitalised (n=22) for HF. After 12 months of pacemaker therapy, 182 (35%) NI patients had a LV ejection fraction (LVEF) &lt;50%, which had a higher incidence at PGR of 197 (40%). Age was the only significant predictor of mortality or HFH for both NI and PGR (hazard ratio (HR), 1.068; 95% confidence interval (CI), 1.039 to 1.098; p&lt;0.001 vs 1.035; 95% CI, 1.007 to 1.064; p=0.014), respectively). Univariate analysis revealed baseline LVEF (2.439; 95 percent CI, 1.279 to 4.659; p=0.007), RV pacing burden, medication and blood chemistry were significant predictors of the combined outcome at PGR but not at NI (Table 2). Multivariable analysis of predictors of LV impairment (&lt;50% LVEF) showed history of MI (odds ratio (OR), 0.47; 95% CI, 0.29 to 0.78; p=0.003), RV pacing burden (1.01; 95% CI, 1.01 to 1.02; p&lt;0.001) and creatinine (1.06; 95% CI, 1.02 to 1.10; p=0.004) were independently associated in both cohorts.

Conclusions

Our data suggest that there remains a similar subgroup of people from initial implantation to PGR at risk of LV impairment that might benefit from medication optimisation or novel pacing strategies. Further research is required to better identifying these people to direct more complex therapies to those with the most to gain.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The research is supported by a National Institute for Health Research (NIHR) clinician scientist fellowship (NIHRCS-2012-032). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. This research was supported by the NIHR Leeds Clinical Research Facility.

Atrial fibrillation and risk of progressive heart failure in patients with preserved ejection fraction heart failure

AIMS

Understanding of the pathophysiology of progressive heart failure (HF) in patients with heart failure with preserved ejection fraction (HFpEF) is incomplete. We sought to identify factors differentially associated with risk of progressive HF death and hospitalization in patients with HFpEF compared with patients with HF and reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Prospective cohort study of patients newly referred to secondary care with suspicion of HF, based on symptoms and signs of HF and elevated natriuretic peptides (NP), followed up for a minimum of 6 years. HFpEF and HFrEF were diagnosed according to the 2016 European Society of Cardiology guidelines. Of 960 patients referred, 467 had HFpEF (49%), 311 had HFrEF (32%), and 182 (19%) had neither. Atrial fibrillation (AF) was found in 37% of patients with HFpEF and 34% with HFrEF. During 6 years follow-up, 19% of HFrEF and 14% of HFpEF patients were hospitalized or died due to progressive HF, hazard ratio (HR) 0.67 (95% CI: 0.47-0.96; P = 0.028). AF was the only marker that was differentially associated with progressive HF death or hospitalization in patients with HFpEF HR 2.58 (95% CI: 1.59-4.21; P < 0.001) versus HFrEF HR 1.11 (95% CI: 0.65-1.89; P = 0.7).

CONCLUSIONS

De novo patients diagnosed with HFrEF have greater risk of death or hospitalization due to progressive HF than patients with HFpEF. AF is associated with increased risk of progressive HF death or hospitalization in HFpEF but not HFrEF, raising the intriguing possibility that this may be a novel therapeutic target in this growing population.

Personalised reprogramming to prevent progressive pacemaker-related left ventricular dysfunction: A phase II randomised, controlled clinical trial

BACKGROUND

Pacemakers are widely utilised to treat bradycardia, but right ventricular (RV) pacing is associated with heightened risk of left ventricular (LV) systolic dysfunction and heart failure. We aimed to compare personalised pacemaker reprogramming to avoid RV pacing with usual care on echocardiographic and patient-orientated outcomes.

METHODS

A prospective phase II randomised, double-blind, parallel-group trial in 100 patients with a pacemaker implanted for indications other than third degree heart block for ≥2 years. Personalised pacemaker reprogramming was guided by a published protocol. Primary outcome was change in LV ejection fraction on echocardiography after 6 months. Secondary outcomes included LV remodeling, quality of life, and battery longevity.

RESULTS

Clinical and pacemaker variables were similar between groups. The mean age (SD) of participants was 76 (+/-9) years and 71% were male. Nine patients withdrew due to concurrent illness, leaving 91 patients in the intention-to-treat analysis. At 6 months, personalised programming compared to usual care, reduced RV pacing (-6.5±1.8% versus -0.21±1.7%; p<0.01), improved LV function (LV ejection fraction +3.09% [95% confidence interval (CI) 0.48 to 5.70%; p = 0.02]) and LV dimensions (LV end systolic volume indexed to body surface area -2.99mL/m2 [95% CI -5.69 to -0.29; p = 0.03]). Intervention also preserved battery longevity by approximately 5 months (+0.38 years [95% CI 0.14 to 0.62; p<0.01)) with no evidence of an effect on quality of life (+0.19, [95% CI -0.25 to 0.62; p = 0.402]).

CONCLUSIONS

Personalised programming in patients with pacemakers for bradycardia can improve LV function and size, extend battery longevity, and is safe and acceptable to patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03627585.

Personalized Rate-Response Programming Improves Exercise Tolerance After 6 Months in People With Cardiac Implantable Electronic Devices and Heart Failure

Background:

Heart failure with reduced ejection fraction (HFrEF) is characterized by blunting of the positive relationship between heart rate and left ventricular (LV) contractility known as the force-frequency relationship (FFR). We have previously described that tailoring the rate-response programming of cardiac implantable electronic devices in patients with HFrEF on the basis of individual noninvasive FFR data acutely improves exercise capacity. We aimed to examine whether using FFR data to tailor heart rate response in patients with HFrEF with cardiac implantable electronic devices favorably influences exercise capacity and LV function 6 months later.

Methods:

We conducted a single-center, double-blind, randomized, parallel-group trial in patients with stable symptomatic HFrEF taking optimal guideline-directed medical therapy and with a cardiac implantable electronic device (cardiac resynchronization therapy or implantable cardioverter-defibrillator). Participants were randomized on a 1:1 basis between tailored rate-response programming on the basis of individual FFR data and conventional age-guided rate-response programming. The primary outcome measure was change in walk time on a treadmill walk test. Secondary outcomes included changes in LV systolic function, peak oxygen consumption, and quality of life.

Results:

We randomized 83 patients with a mean±SD age 74.6±8.7 years and LV ejection fraction 35.2±10.5. Mean change in exercise time at 6 months was 75.4 (95% CI, 23.4 to 127.5) seconds for FFR-guided rate-adaptive pacing and 3.1 (95% CI, −44.1 to 50.3) seconds for conventional settings (analysis of covariance; P =0.044 between groups) despite lower peak mean±SD heart rates (98.6±19.4 versus 112.0±20.3 beats per minute). FFR-guided heart rate settings had no adverse effect on LV structure or function, whereas conventional settings were associated with a reduction in LV ejection fraction.

Conclusions:

In this phase II study, FFR-guided rate-response programming determined using a reproducible, noninvasive method appears to improve exercise time and limit changes to LV function in people with HFrEF and cardiac implantable electronic devices. Work is ongoing to confirm our findings in a multicenter setting and on longer-term clinical outcomes.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02964650.

Comparison of function of created wetlands of two age classes in central Pennsylvania

Hydrogeomorphic (HGM) functional assessment models were used to assess whether function in created wetlands of two ages (1 year old and >12 years old) was equivalent to that of natural (reference) mainstem floodplain wetlands. Reference wetlands scored higher than both created age classes for providing energy dissipation and short-term surface water storage. Reference wetlands scored higher in maintaining native plant community and structure than 1-year-old sites, and 12-year-old wetlands scored higher than reference sites for providing vertebrate habitat structure. Analysis of individual model variables showed that reference wetlands had greater vegetative biomass and higher soil organic matter content than both created wetland age classes. Created wetlands were farther from natural wetlands and had smaller mean forest patch sizes within a 1-km-radius circle around the site than did the reference sites, indicating less hydrologic connectivity. Created wetlands also had less microtopographic variation than reference wetlands. The 1-year-old created sites were placed in landscape settings with greater land use diversity and road density than reference sites. The 12-year-old sites had a higher gradient and a higher percentage of their surrounding area in urban land use. These results show that the created wetlands were significantly structurally different (if not functionally so) from reference wetlands even after 12 years. The most profound differences were in hydrology and the characteristics of the surrounding landscape. More attention needs to be focused on placing created wetlands in appropriate settings to encourage proper hydrodynamics, eliminate habitat fragmentation, and minimize the effects of stressors to the site.

Maternal corticosterone further reduces the reproductive function of male offspring hatched from eggs laid by quail hens selected for exaggerated adrenocortical stress responsiveness

Activation of the hypothalamic-pituitary-adrenal (HPA) axis can depress the hypothalamic-pituitary-testicular axis. Male quail cloacal gland (CG) size and foam production shows androgen dependency, and males selected for exaggerated [high stress (HS)] rather than reduced [low stress (LS)] plasma corticosterone (B) stress response exhibit reduced CG and testes development. High stress hens also deposit more B into egg yolks than LS ones, and quail hens given B produce chicks that have a reduced growth rate and adults with heightened HPA responsiveness. Herein, we gave LS and HS hens no B [empty implants, control (CON)] or B-filled implants and assessed the reproductive performances of these hens and their male offspring. Mortality was similarly elevated in LS and HS B-treated hens, but only HS B-implanted hens showed reduced egg production. In male offspring, CG volume (CVOL), intensity of CG foam production (CFP), and the proportion of individuals that produced CG foam were measured from 4 to 11 wk of age. At 6 wk, BW, and at 15 wk, BW, testes weight (TWT), and TWT relative to BW were also determined. Hen treatments did not affect male chick CVOL at 4 wk, but CVOL differed thereafter as follows: LS CON > LS B = HS CON = HS B at 5 and 6 wk and LS CON > LS B > HS CON = HS B from 7 to 11 wk. By 8 wk, and thereafter, CFP differed as follows: LS CON > LS B > HS CON > HS B. Group differences in the proportion of individuals that produced CG foam generally supported CFP findings from 4 to 8 wk of age. Body weight did not differ by treatment at 6 wk of age. By 15 wk, TWT were similarly depressed in both HS groups. However, similarly higher 15-wk BW in the LS-CON and HS-B groups contributed to TWT relative to BW differences as follows: LS-B > LS-CON > HS-B; LS-CON = HS-CON; LS-B > HS-CON; and, HS-CON = HS-B. Both selection for exaggerated HPA responsiveness and maternal B treatment negatively affected the reproductive function of HS male offspring.

Losing function through wetland mitigation in central Pennsylvania, USA

In the United States, the Clean Water Act requires mitigation for wetlands that are negatively impacted by dredging and filling activities. During the mitigation process, there generally is little effort to assess function for mitigation sites and function is usually inferred based on vegetative cover and acreage. In our study, hydrogeomorphic (HGM) functional assessment models were used to compare predicted and potential levels of functional capacity in created and natural reference wetlands. HGM models assess potential function by measurement of a suite of structural variables and these modeled functions can then be compared to those in natural, reference wetlands. The created wetlands were built in a floodplain setting of a valley in central Pennsylvania to replace natural ridge-side slope wetlands. Functional assessment models indicated that the created sites differed significantly from natural wetlands that represented the impacted sites for seven of the ten functions assessed. This was expected because the created wetlands were located in a different geomorphic setting than the impacted sites, which would affect the type and degree of functions that occur. However, functional differences were still observed when the created sites were compared with a second set of reference wetlands that were located in a similar geomorphic setting (floodplain). Most of the differences observed in both comparisons were related to unnatural hydrologic regimes and to the characteristics of the surrounding landscape. As a result, the created wetlands are not fulfilling the criteria for successful wetland mitigation.

Cloacal Gland and Gonadal Photoresponsiveness in Male Japanese Quail Selected for Divergent Plasma Corticosterone Response to Brief Restraint

Corticosterone is linked to testicular depression, and in Coturnix, a relatively photorefractory species, day length and androgen dependency in cloacal gland development and foam production are evident. Furthermore, male quail selected for reduced (low stress, LS) rather than exaggerated (high stress, HS) plasma corticosterone stress response show more photo-induced reproductive development, greater resistance to reproductive declines induced by exposure to very short days, and a quicker recovery to a higher reproductive level upon return to long days. To determine whether a milder reduction in day length would also influence stress line reproductive photoresponsiveness, and perhaps photorefractoriness, males grown on 16 h of light were given 13 h of light for 4 wk followed by a return to long days for 12 wk. Cloacal gland measurements were made following the initial stimulatory photoperiod and weekly thereafter during the 2 light treatments. Plasma testosterone was determined initially, after 4 wk of light reduction, and at the end of the study, along with BW, testes weight (TWT), and TWT relative to BW. Cloacal gland volume (CVOL) was greater in LS than HS males grown on long days. Whereas exposure to 13 h of light reduced CVOL in both lines, line differences (LS > HS) persisted during the first 3 wk of light reduction. Moreover, by 2 wk of rephotostimulation, and weekly thereafter, line differences (LS > HS) in CVOL reemerged. Cloacal gland foam production and the proportion of individuals that produced cloacal gland foam responses reflected changes in CVOL. The BW did not differ by line, yet LS males had a higher TWT and TWT relative to BW than HS ones. All individuals, however, exhibited relative photorefractory responses. Whereas none of the LS males completely resisted reproductive regression induced by a 3 h light reduction, LS males showed other reproductive benefits upon mild photocastration and subsequent rephotostimulation (e.g., greater resistance to CVOL and cloacal gland foam production losses during a mild light crash and quicker restoration to full reproductive potential upon relighting).

Founder's Award, Society for Biomaterials. Sixth World Biomaterials Congress 2000, Kamuela, HI,May 15-20, 2000. Really smart bioconjugates of smart polymers and receptor proteins

Over the past 18 years we have been deeply involved with the synthesis and applications of stimuli-responsive polymer systems, especially polymer-biomolecule conjugates. This article summarizes our work with one of these conjugate systems, specifically polymer-protein conjugates. We include conjugates prepared by random polymer conjugation to lysine amino groups, and also those prepared by site-specific conjugation of the polymer to specific amino acid sites that are genetically engineered into the known amino acid sequence of the protein. We describe the preparation and properties of thermally sensitive random conjugates to enzymes and several affinity recognition proteins. We have also prepared site-specific conjugates to streptavidin with temperature-sensitive polymers, pH-sensitive polymers, and light-sensitive polymers. The preparation of these conjugates and their many fascinating applications are reviewed in this article.

Characterization of the metabolites of the antidepressant drug nefazodone in human urine and plasma

Metabolism of the antidepressant drug nefazodone was studied in humans after single and multiple 50 and 200 mg oral doses of [14C] nefazodone as part of a single and multiple dose balance study. Deuterium was included in the molecule to facilitate structural characterization of the metabolites by mass spectrometry. Metabolites were isolated from a 0-24 hr pooled urine from three subjects and purified to homogeneity by HPLC. Chemical structures of the metabolites were proposed based on collisionally induced dissociation (CID) and electron impact ionization MS. The profile of radioactivity showed three main urinary metabolites, one of which was a conjugate, and several minor metabolites. The three major metabolites were identified as the phenoxyethyl triazolone propionic acid resulting from N-dealkylation of both nefazodone and hydroxynefazodone (OH-Nef), as well as a corresponding phenoxyethyl triazolone propanol metabolite of N-dealkylated nefazodone, present exclusively as a conjugate. The more polar minor components were not identified. The excretion of total radioactivity in the 24-hr sample was 49% of the dose, of which the identified metabolites comprised 38% of the dose. There was no difference in the qualitative or quantitative urinary profile of the metabolites at 50 or 200 mg dose levels after single or multiple oral dosing. These N-dealkylated metabolites were also present in pooled human plasma samples along with nefazodone, OH-Nef, and an unknown metabolite that was present in plasma in large amounts relative to nefazodone and OH-Nef. This metabolite was isolated from plasma and from a human liver S9 incubation and identified by CID tandem MS and NMR as the triazoledione of nefazodone.(ABSTRACT TRUNCATED AT 250 WORDS)

Distinguishing negligence from intentional tort when a health care provider deviates from a patient's consent

A number of California appellate courts have held that a health care provider's unintentional deviation from a patient's consent will support a cause of action for "technical battery"--an intentional tort. This policy has allowed plaintiffs to circumvent California's statutory malpractice damage limits and seek punitive damages, thus posing a significant threat to the foundation of California medical malpractice tort law reform. The California Supreme Court recently acknowledged the problem and appears to be taking steps toward a solution.

Activated, N-substituted acrylamide polymers for antibody coupling: application to a novel membrane-based immunoassay

A room-temperature-precipitable, activated terpolymer consisting of N-isopropylacrylamide (NIPAAm)/N-n-butylacrylamide(nBAAm)/N-acryloxysuccinimide (NASI) (LCST = 7-13 degrees C) at a monomer feed ratio of 60:40:2.5, respectively, was prepared and conjugated to an antibody. The conjugate was evaluated in a novel cellulose acetate (CA) membrane-based immunoassay which utilizes the especially strong physical attachment of the polymer to CA to bind and concentrate the polymer attached protein onto the membrane. When compared in the CA membrane immunoassay to the antibody-poly(NIPAAm) conjugate prepared via anhydrous copolymerization of NIPAAm and NASI at the monomer feed ratio of 40:1, respectively, the performance of the NIPAAm/nBAAm/NASI terpolymer was superior to that of the NIPAAm/NASI copolymer (LCST = 32 degrees C) when the studies were carried out at room temperature. However, the terpolymer and copolymer gave equivalent performance when the assay mixture was heated to 45 degrees C. These results indicate the importance of the LCST of the polymer component of the Ab-polymer conjugate to its adsorption and binding on the CA membrane.

Temperature-dependent absorption/desorption behavior of lower critical solution temperature (LCST) polymers on various substrates

We have been studying adsorption and retention (resistance to desorption) behavior of temperature sensitive LCST polymers on different substrates as a function of temperature. According to our studies with Poly 64 (a copolymer of 60% (mol) NIPAAm and 40% (mol) NnBAAm, LCST = 8.5 degrees C in water), the copolymer retention depends on the rinse temperature. When the rinse temperature is above the LCST, the polymer adheres well to most surfaces. On the contrary, at rinse temperatures below the LCST, most of the adsorbed polymer is easily rinsed off. These studies are relevant to our work on the thermally reversible adsorption of LCST polymers conjugated to peptides and proteins, such as affinity ligands, for uses in immunoassays and affinity separations. The interaction between the LCST polymer and most hydrophobic polymer surfaces is mainly due to hydrophobic interactions, and the critical surface tension (gamma c) and the solubility parameter (delta) of the solid polymer substrate are the most important factors which influence the LCST polymer adsorption and retention. The critical surface tension appears to correlate best with the LCST polymer adsorption levels on different substrates, while the solubility parameter correlates best with the retention of the adsorbed polymer. According to our preliminary study, n-butyl groups probably interact more strongly with the substrates than isopropyl groups because of the greater hydrophobic surface area of the former groups.

Effect of sodium salicylate, aspirin, and ibuprofen on enzymes required by the chondrocyte for synthesis of chondroitin sulfate

OBJECTIVE

To examine the effects of sodium salicylate (Sal), aspirin [acetylsalicylic acid (ASA)] and ibuprofen (Ibu) (as the racemic mixture and the R- and S-enantiomers) on the activities of 2 enzymes involved in the biosynthesis of the hexose components of chondroitin sulfate (CS), i.e., UDP-glucose dehydrogenase (UDP-GD) and glutamine-fructose-6-phosphate-aminotransferase (GFAT), and of glucuronosyltransferase (GT), an enzyme involved in elongation of the nascent CS chain.

METHODS

UDP-GD and GT were obtained commercially. A homogenate of bovine articular cartilage chondrocytes was employed as a source of GFAT. In each case, enzymatic activity was measured spectrophotometrically.

RESULTS

Neither UDP-GD nor GFAT was inhibited by concentrations of Sal, ASA or Ibu that were achieved clinically in joint tissues (e.g., 1.0 mM Sal and ASA, 170 microM Ibu). In contrast, GT activity was inhibited by Sal and ASA in a concentration dependent fashion; at 1.0 mM, a concentration commonly reached in synovial fluid of patients treated with an antiinflammatory dose of the drug, GT activity in the presence of Sal and ASA was 54% (p = 0.001) and 75% (p = 0.05), respectively, of the control value. In contrast, a clinically relevant concentration of Ibu had no effect on GT activity.

CONCLUSION

Salicylates may suppress cartilage proteoglycan synthesis by inhibiting GT.

Health care litigation: assuring consistency and proportionality in punitive damages awards

This article, the ninth in a series on health care litigation, explains possible reforms that could be implemented to prevent juries from awarding unreasonable and unfair amounts of punitive damages. One way to minimize this problem would be to establish a system that promotes consistency in punitive damages awards. Another reform would involve instituting mechanisms to ensure proportionality in punitive damages awards. This article explores the steps involved in establishing a new system, and the benefit to defendants if the punitive damages system is reformed.

Health care litigation: achieving fairness and reasonableness in punitive damages awards

This article, the eighth in a series on health care litigation, discusses whether due process considerations require that the common-law procedures for awarding punitive damages be modified and whether juries have undue discretion in awarding punitive damages. The authors analyze an important recent United States Supreme Court punitive damages case and examine the changes states may need to make in their punitive damages assessment procedures to conform with the Supreme Court's holding.

Health care litigation: a common theory of noneconomic damages compensation

In this article and the preceding article, the sixth and seventh in a series on health care litigation, the topic of noneconomic damages in medical malpractice cases is discussed. The preceding article addressed the law regarding noneconomic damages for emotional distress to third parties. This article describes a number of recent attempts to expand other categories of noneconomic damages, shows how this expansion can result in tort law problems, and suggests a possible solution.

Health care litigation: recent trends in the law of noneconomic damages--emotional distress

This article and an article to follow, the sixth and seventh in a series, will address the topic of noneconomic damages in medical malpractice cases. Pain and suffering, emotional distress, loss of consortium, loss of a chance, hedonic damages, and other forms of nonpecuniary damages have played a major role in the increased recovery of compensatory damages from health care providers. This article will provide an overview of the subject of noneconomic damages and an in-depth discussion of the law regarding damages for emotional distress to third parties as it has evolved in the State of California.

Application of a thermally-reversible polymer-antibody conjugate in a novel membrane-based immunoassay

We have developed a novel method to immobilize antibodies onto a cellulose acetate membrane using a conjugate of an N-isopropylacrylamide polymer covalently bound to the antibody. When compared with the unconjugated antibody, over 30-fold increase in retention of the antibody on the membrane was observed when it was conjugated to poly (N-isopropylacrylamide). Studies of the polymer-membrane interaction suggest a combination of hydrophobic and ionic forces, especially the former, is responsible for the high retention. We applied this novel immobilization technology in the development of a membrane-based immunoassay.

Health care litigation: understanding and explaining causation

This is the fourth in a series of articles on health care litigation. This article focuses on the substantive aspects of causation, one of the most difficult and controversial issues in health care litigation. The article identifies the differing perspectives of the medical and legal professions on the concept of cause and proposes an approach to clarify the concept for juries, judges, and arbitrators. An analysis of the procedural aspects of causation will appear in the next issue of The Medical Staff Counselor.

Health care litigation: managing an appeal

This is the third in a series of articles on health care litigation. This article illustrates how unfavorable appellate precedent can occur and proposes techniques for preventing such adverse results.

Health care litigation: the arbitration alternative for dispute resolution

This is the second in a series of articles on health care litigation. This article focuses on the benefits of arbitration as an alternative dispute mechanism for health care providers. The use of arbitration offers speed and economy to the parties. For the health care provider, arbitration can reduce litigation expense and the likelihood of "runaway" jury verdicts.

Sunscreen testing using the mouse ear model

During the developmental stages of sunscreen formulation it is desirable to have a simple, accurate and inexpensive biological model to test product effectiveness. Another desirable attribute is a quantitative, unbiased response endpoint for evaluation. We have developed such a test system based upon the ear swelling response of hairless albino mice. With this system, irradiation times are greatly reduced; furthermore, the response parameter is metric and can be determined noninvasively with an inexpensive micrometer. Protection factors determined with the mouse ear model show high correlation with the sun protection factors as determined on human subjects (r = 0.92) and were linearly related over a wide range of values. This new method affords a simple, accurate and inexpensive system for evaluation of efficacy and safety of new products.

Health care litigation: new views on litigation management

This is the first in a series of articles on health care litigation. The first article describes a new perspective on litigation management and suggests techniques to achieve better results at more reasonable cost.

Health care litigation: proving--and disproving--causation

This article, the fifth in a series, focuses on procedural issues concerning the causation element in health care litigation. The fourth article in the series identified the different perspectives of the medical and legal professions on the concept of cause and proposed an approach to clarify the concept for juries, judges, and arbitrators. This article analyzes the procedural aspects of proving causation or--as most health care providers in litigation often find it necessary to do--disproving causation.

Duplex carotid ultrasound

Technical advances in the field of ultrasound have resulted in the development of a high resolution real-time B-mode imaging system that permits direct Doppler analysis of hemodynamic abnormalities. This system combines both anatomic information and physiological information which permits detailed analysis of the entire spectrum of disease occurring at the carotid bifurcation. Future developments will permit improved management of patients at risk for stroke from carotid vascular disease.

Different biologic effectiveness of blacklight fluorescent lamps available for therapy with psoralens plus ultraviolet A

In 1976 we reported a change in spectral distribution of "blacklight" fluorescent lamps. It was not possible to determine the spectral composition of these lamps by any codes or packaging materials. Phototherapy booths utilizing standard BL-HO lamps will accept lamps of at least two spectral distributions; both types are commercially available. This study was conducted to determine the biologic efficacy of these two lamp types that we refer to as BL-O and BL-N. The BL-O spectrum had a peak emission at approximately 350 nm with 98% of the energy between 320 and 400 nm. The BL-N spectrum had its peak emission at 365 nm with a range from 340 to 400 nm. The BL-O spectrum was at least 2.5 to 4 times as effective as BL-N in causing minimally perceptible phototoxicity in albino hairless mice given oral doses of 8 mg/kg of 8-methoxypsoralen. Food and Drug Administration (FDA)-approved specifications imply that the BL-O spectrum is to be used for psoralens and ultraviolet A (PUVA) phototherapy. If lamps with the BL-N spectrum are replaced by lamps with the BL-O spectrum, the metered dose must be reduced to no more than one-fourth of the previous dose or the patient may suffer serious phototoxic reactions.

New California strategy for medical assistance favors public health and organized plans

In coming months, county governments in California will begin implementing regulations enacted by State Assembly that will change the settings for treatment of Medi-Cal (Medicaid) patients. The change will be dramatic, channeling medical assistance patients out of the offices of individual private practice physicians and into the offices of salaried doctors in public health settings or offices of doctors participating in organized health plans. Negotiated contracts with counties, institutions and non-institutional providers, patients, and fixed rates of reimbursement will become the parameters of medical service for providers of health care in the state's medical assistance program. For urban private solo practitioners in California whose practices rely heavily on publicly-supported patients, these changes hold a major threat, and for physicians throughout the nation it is a situation which should be watched carefully, because California is well known as a state which gives birth to changes that later appear in other states.

New 9-stubstituted 3-N,O-diacetylhydroxylaminofluorenes: enhanced electrophilicity and mutagenicity. Derivatives of fluorene. 38

The compound 2-acetamidofluorene is a potent hepatocarcinogen; its N-acetoxy derivative (2-NOAc-AAF), a model ultimate form of the carcinogen, is strongly mutagenic and is chemically reactive with nucleophiles. The isomeric 3-acetamidofluorene is a mammary carcinogen, but is not hepatocarinogenic; its N-acetoxy derivative (3-NOAc-AAF) is not reactive with nucleophiles. Derivatives of 3-NOAc-AAF containing electron-donating groups in positions conjugated with the 3-position have been synthesized. These show increased electrophilicity and mutagenicity. Thus, by electronic manipulation of the leaving-group capacity of the -OAc group of 3-NOAc-AAF, we have obtained compounds with increased biological activity, as well as increased chemical reactivity. Future experiments could show whether in vivo effects of these derivatives of 3-NOAc-AAF are more like the effects of 2-NOAc-AAF or of 3-NOAc-AAF.

New compounds: derivatives of fluorene XXXVII: 9-substituted 3-nitrofluorenes

New 9-substituted 3-nitrofluorenes were prepared as potential intermediates in a study of modified electrophilicity and mutagenicity of the carcinogen 3-N,O-diacetylhydroxylaminofluorene. The reported derivatives, together with some already known 9-substituted 3-nitrofluorenes, were too unstable to survive the reducing conditions required to transform the nitro group to the corresponding hydroxylamine.