Statins and risks of dementia among patients with heart failure: a population-based retrospective cohort study in Hong Kong

Background

Heart failure (HF) and dementia frequently co-exist with shared pathological mechanisms and risk factors. Our study aims to investigate the association between statin therapy and the risks of dementia and its subtypes among patients with HF.

Methods

The Hong Kong Clinical Data Analysis and Reporting System database was interrogated to identify patients with incident HF diagnosis from 2004 to 2018, using ICD 9/ICD 10 codes. Inverse probability of treatment weighting (IPTW) was used to balance baseline covariates between statin users (N = 54,004) and non-users (N = 50,291). The primary outcomes were incident all-cause dementia, including subtypes of Alzheimer's disease, vascular dementia, and unspecified dementia. Cox proportional-hazard model with competing risk regression was performed to estimate the sub-distribution hazards ratio (SHR) with corresponding 95% confidence intervals (CI) of the risks of all-cause dementia and its subtypes that are associated with statin use.

Findings

Of all eligible patients with HF (N = 104,295), the mean age was 74.2 ± 13.6 years old and 52,511 (50.3%) were male. Over a median follow-up of 9.9 years (interquartile range [IQR]: 6.4-13.0), 10,031 (9.6%) patients were diagnosed with dementia, among which Alzheimer's disease (N = 2250), vascular dementia (N = 1831), and unspecified dementia (N = 5950) were quantified separately. After IPTW, statin use was associated with a 20% lower risk of incident dementia compared with non-use (multivariable-adjusted SHR 0.80, 95% CI 0.76-0.84). Stratified by subtypes of dementia, statin use was associated with a 28% lower risk of Alzheimer's disease (SHR 0.72, 95% CI 0.63-0.82), 18% lower risk of vascular dementia (SHR 0.82, 95% CI 0.70-0.95), and a 20% lower risk of unspecified dementia (SHR 0.80, 95% CI 0.75-0.85).

Interpretation

In patients with HF, statin use was associated with a significantly lower risk of all-cause dementia and its subtypes, including Alzheimer's disease, vascular dementia, and unspecified dementia. Both randomized trials and experimental studies to validate the potential neuroprotective effect of statin are warranted.

Funding

No funding was provided for this study.

Statin Therapy Is Associated With a Lower Risk of Heart Failure in Patients With Atrial Fibrillation: A Population-Based Study

BACKGROUND

Whether statin use can reduce the risk of heart failure (HF) remains controversial. The present study evaluates the association between statin use and HF in patients with atrial fibrillation.

METHODS AND RESULTS

Patients with newly diagnosed atrial fibrillation from 2010 to 2018 were included. An inverse probability of treatment weighting was used to balance baseline covariates between statin users (n=23 239) and statin nonusers (n=29 251). The primary outcome was incident HF. Cox proportional hazard models with competing risk regression were used to evaluate the risk of HF between statin users and nonusers. The median age of the cohort was 74.7 years, and 47.3% were women. Over a median follow-up of 5.1 years, incident HF occurred in 3673 (15.8%) statin users and 5595 (19.1%) statin nonusers. Statin use was associated with a 19% lower risk of HF (adjusted subdistribution hazard ratio, 0.81 [95% CI, 0.78-0.85]). Restricted to the statin users, duration of statin use was measured during follow-up; compared with short-term use (3 months to <2 years), there was a stepwise reduction in the risk of incident HF among those with 2 to <4 years of statin use (subdistribution hazard ratio, 0.86 [95% CI, 0.84-0.88]), 4 to <6 years of statin use (subdistribution hazard ratio, 0.74 [95% CI, 0.72-0.76]), and ≥6 years of statin use (subdistribution hazard ratio, 0.71 [95% CI, 0.69-0.74]). Subgroup analysis showed consistent reductions in the risk of HF with statin use.

CONCLUSIONS

Statin use was associated with a decreased risk of incident HF in a duration-dependent manner among patients with atrial fibrillation.

Morphological and functional types of tricuspid regurgitation: prognostic value in patients undergoing tricuspid annuloplasty during left-sided valvular surgery

BACKGROUND

The nonuniform benefit of tricuspid annuloplasty may be explained by the proportionality of tricuspid regurgitation (TR) severity to right ventricular (RV) area. The purpose of this study was to delineate distinct morphological phenotypes of functional TR and investigate their prognostic implications in patients undergoing tricuspid annuloplasty during left-sided valvular surgery.

METHODS

The ratios of pre-procedural effective regurgitant orifice area (EROA) with right ventricular end-diastolic area (RVDA) were retrospectively assessed in 290 patients undergoing tricuspid annuloplasty. Based on optimal thresholds derived from penalized splines and maximally selected rank statistics, patients were stratified into proportionate (EROA/RVDA ratio ≤ 1.74) and disproportionate TR (EROA/RVDA ratio > 1.74).

RESULTS

Overall, 59 (20%) and 231 (80%) patients had proportionate and disproportionate TR, respectively. Compared to those with proportionate TR, patients with disproportionate TR were older, had a higher prevalence of atrial fibrillation, lower pulmonary pressures, more impaired RV function, and larger tricuspid leaflet tenting area. Over a median follow-up of 4.1 years, 79 adverse events (47 heart failure hospitalizations and 32 deaths) occurred. Patients with disproportionate TR had higher rates of adverse events than those with proportionate TR (32% vs 10%; P = 0.001) and were independently associated with poor outcomes on multivariate analysis. TR proportionality outperformed guideline-based classification of TR severity in outcome prediction and provided incremental prognostic value to both the EuroSCORE II and STS score (incremental χ2 = 6.757 and 9.094 respectively; both P < 0.05).

CONCLUSIONS

Disproportionate TR is strongly associated with adverse prognosis and may aid patient selection and risk stratification for tricuspid annuloplasty with left-sided valvular surgery.

Chronic kidney disease begets heart failure and vice versa: temporal associations between heart failure events in relation to incident chronic kidney disease in type 2 diabetes

AIM

To investigate the interplay of incident chronic kidney disease (CKD) and/or heart failure (HF) and their associations with prognosis in a large, population-based cohort with type 2 diabetes (T2DM).

METHODS

Patients aged ≥18 years with new-onset T2DM, without renal disease or HF at baseline, were identified from the territory-wide Clinical Data Analysis Reporting System between 2000 and 2015. Patients were followed up until December 31, 2020 for incident CKD and/or HF and all-cause mortality.

RESULTS

Among 102 488 patients (median age 66 years, 45.7% women, median follow-up 7.5 years), new-onset CKD occurred in 14 798 patients (14.4%), in whom 21.7% had HF. In contrast, among 9258 patients (9.0%) with new-onset HF, 34.6% had CKD. The median time from baseline to incident CKD or HF (4.4 vs. 4.1 years) did not differ. However, the median (interquartile range) time until incident HF after CKD diagnosis was 1.7 (0.5-3.6) years and was 1.2 (0.2-3.4) years for incident CKD after HF diagnosis (P < 0.001). The crude incidence of CKD was higher than that of HF: 17.6 (95% confidence interval [CI] 17.3-17.9) vs. 10.6 (95% CI 10.4-10.9)/1000 person-years, respectively, but incident HF was associated with a higher adjusted-mortality than incident CKD. The presence of either condition (vs. CKD/HF-free status) was associated with a three-fold hazard of death, whereas concomitant HF and CKD conferred a six to seven-fold adjusted hazard of mortality.

CONCLUSION

Cardiorenal complications are common and are associated with high mortality risk among patients with new-onset T2DM. Close surveillance of these dual complications is crucial to reduce the burden of disease.

Incidence, Clinical Correlates, and Prognostic Impact of Dementia in Heart Failure: A Population-Based Cohort Study

Background

Heart failure (HF) may increase the risk of dementia via shared risk factors.

Objectives

The authors investigated the incidence, types, clinical correlates, and prognostic impact of dementia in a population-based cohort of patients with index HF.

Methods

The previously territory-wide database was interrogated to identify eligible patients with HF (N = 202,121) from 1995 to 2018. Clinical correlates of incident dementia and their associations with all-cause mortality were assessed using multivariable Cox/competing risk regression models where appropriate.

Results

Among a total cohort aged ≥18 years with HF (mean age 75.3 ± 13.0 years, 51.3% women, median follow-up 4.1 [IQR: 1.2-10.2] years), new-onset dementia occurred in 22,145 (11.0%), with age-standardized incidence rate of 1,297 (95% CI: 1,276-1,318) per 10,000 in women and 744 (723-765) per 10,000 in men. Types of dementia were Alzheimer's disease (26.8%), vascular dementia (18.1%), and unspecified dementia (55.1%). Independent predictors of dementia included: older age (≥75 years, subdistribution hazard ratio [SHR]: 2.22), female sex (SHR: 1.31), Parkinson's disease (SHR: 1.28), peripheral vascular disease (SHR: 1.46), stroke (SHR: 1.24), anemia (SHR: 1.11), and hypertension (SHR: 1.21). The population attributable risk was highest for age ≥75 years (17.4%) and female sex (10.2%). New-onset dementia was independently associated with increased risk of all-cause mortality (adjusted SHR: 4.51; P < 0.001).

Conclusions

New-onset dementia affected more than 1 in 10 patients with index HF over the follow-up, and portended a worse prognosis in these patients. Older women were at highest risk and should be targeted for screening and preventive strategies.

Prognostic value of longitudinal assessment of inflammatory and nutritional status in patients undergoing valvular heart surgery

Funding Acknowledgements

Type of funding sources: None.

Background

Novel strategies to improve the long-term risk stratification of valvular surgery are urgently needed as a result of the increasing prevalence of valvular heart diseases globally.

Purpose

This study aimed to evaluate the prognostic implications of longitudinal assessment of inflammatory and nutritional status in patients undergoing valvular surgery.

Methods

1046 patients who underwent valvular surgery were stratified into three groups based on their inflammatory (neutrophil-to-lymphocyte ratio [NLR]) and nutritional status (prognostic nutritional index [PNI]): without inflammation and malnutrition (normal), inflammation or malnutrition alone (mild), and concomitant inflammation and malnutrition (severe). Optimal NLR and PNI thresholds for predicting all-cause mortality were determined using receiver-operating characteristic analysis. The endpoints were all-cause mortality, cardiovascular death and adverse events (composite of death and heart failure [HF] hospitalization).

Results

Over a median follow-up of 4.3 years (IQR: 2.6 to 6.4 years), 139 (13.3%) deaths and 148 (14.1%) HF hospitalizations occurred. Based on the optimal cut-off of NLR &gt;4.06 (inflammation) and PNI &lt;45.8 (malnutrition), 714 (68.3%), 214 (20.5%) and 118 (11.3%) patients were categorized into normal, mild and severe groups respectively. Compared with patients without inflammation and malnutrition, those with concomitant inflammation and malnutrition before surgery had the highest risk of all-cause mortality (hazard ratio [HR] 5.60, 95% confidence interval [CI] 3.66-8.57), cardiovascular death (subdistribution HR [SHR] 5.19, 95% CI 2.33-11.60) and adverse events (HR 3.14, 95% CI 2.25-4.38) (p&lt;0.001 for all), adjusted for demographics, cardiovascular risk factors and diseases, medications, valvular surgeries and EuroSCORE II. Discriminatory improvement for predicting all-cause mortality was observed when baseline NLR and PNI were added to EuroSCORE II (C-statistic 0.77 vs 0.73, p=0.04; continuous net reclassification improvement [cNRI] 0.24, 95% CI 0.12-0.36, p=0.004; integrated discrimination improvement [IDI] 0.04, 95% CI 0.01-0.08, p=0.004) and STS score (C-statistic 0.78 vs 0.73, p=0.03; cNRI 0.16, 95% CI 0.06-0.32, p=0.002; IDI 0.02, 95% CI 0.000-0.049, p=0.048) respectively. 1 year following surgery (n=740), those with persistent concomitant inflammation and malnutrition experienced the highest risk of all-cause mortality (HR 8.82, 95% CI 4.21-18.49), cardiovascular death (SHR 12.63, 95% CI 3.85-41.39) and adverse events (HR 5.83, 95% CI 3.16-10.76) than those without (p&lt;0.001 for all).

Conclusion

Concomitant inflammation and malnutrition is common and is strongly associated with mortality and HF in patients undergoing valvular surgery. Beyond conventional risk scores, assessments of inflammatory and nutritional status using NLR and PNI before and after surgery may provide additional prognostic value for long-term outcomes following valvular surgery.

Prediabetes Is Associated With Increased Risk of Heart Failure Among Patients With Atrial Fibrillation

OBJECTIVE

To evaluate the association between prediabetes and heart failure (HF) and the association of HF with changes in glycemic status.

RESEARCH DESIGN AND METHODS

Patients newly diagnosed with atrial fibrillation (AF) between 2015 and 2018 were divided into three groups (normoglycemia, prediabetes, and type 2 diabetes) according to their baseline glycemic status. The primary outcome was incident HF. The Fine and Gray competing risks model was applied, with death defined as the competing event.

RESULTS

Among 17,943 patients with AF (mean age 75.5 years, 47% female), 3,711 (20.7%) had prediabetes, and 10,127 (56.4%) had diabetes at baseline. Over a median follow-up of 4.7 years, HF developed in 518 (14%) patients with normoglycemia, 646 (15.7%) with prediabetes, and 1,795 (17.7%) with diabetes. Prediabetes was associated with an increased risk of HF compared with normoglycemia (subdistribution hazard ratio [SHR] 1.12, 95% CI 1.03-1.22). In patients with prediabetes at baseline, 403 (11.1%) progressed to diabetes, and 311 (8.6%) reversed to normoglycemia at 2 years. Compared with remaining prediabetic, progression to diabetes was associated with an increased risk of HF (SHR 1.50, 95% CI 1.13-1.97), whereas reversion to normoglycemia was associated with a decreased risk (SHR 0.61, 95% CI 0.42-0.94).

CONCLUSIONS

Prediabetes was associated with an increased risk of HF in patients with AF. Compared with patients who remained prediabetic, those who progressed to diabetes at 2 years experienced an increased risk of HF, whereas those who reversed to normoglycemia incurred a lower risk of HF.

A historical cohort study of glycemic control in patients with concurrent type 2 diabetes and substance use disorder treated in a primary care setting

BACKGROUND

Substance use disorder (SUD) is a known barrier to patient-self-management, which can hinder efforts to achieve treatment goals in type 2 diabetes (T2D) when the conditions coexist.

OBJECTIVE

Identify the association between SUD and glycemic control in patients with T2D treated in a primary care setting.

METHODS

This retrospective cohort study included patients with T2D treated by providers at family medicine clinics at an academic medical center and its affiliated regional sites from January 2014 to October 2019. Study index date was the first A1c recorded when T2D and SUD diagnoses had both been documented in the medical record. Glycemic control, measured by hemoglobin A1c (A1c), was identified at baseline and over a 12-month follow-up period and was compared between SUD and non-SUD patients.

RESULTS

Of 9568 included patients with T2D, 468 (4.9%) had a SUD diagnosis. In 237 SUD and 4334 non-SUD patients with A1c data, mean (SD) baseline A1c was 8.2% (2.5) and 7.9% (2.1), respectively (P = 0.043). A1c reduction was statistically greater in SUD patients than non-SUD patients (-0.31% versus -0.06%, respectively; P = 0.015), although the clinical significance is modest. In a multivariable linear regression analysis, follow-up A1c was lower in the SUD versus non-SUD patients (coefficient -0.184, 95% CI -0.358, -0.010; P = 0.038).

CONCLUSIONS

Patients with T2D and SUD had higher baseline A1c but this difference was minimized over a 12-month follow-up period. Additional research is warranted to determine long-term glycemic control and barriers to attaining and maintaining glycemic control in patients with T2D and SUD.

Arkansas community's attitudes toward the regulation of medical cannabis and the pharmacist's involvement in Arkansas medical cannabis

OBJECTIVES

This study explored the attitudes of the Arkansas community toward medical cannabis (MC) regulation and the role of pharmacists in dispensing MC before the product became available and examined whether participants' demographics (e.g., age, gender) and characteristics (e.g., history of cannabis use) were associated with these attitudes.

DESIGN

Cross-sectional survey.

SETTING AND PARTICIPANTS

Using social media, a university research registry, and posted flyers, we invited residents of Arkansas to participate in the self-administered online survey study during a 3-month period, February to April, in 2018.

OUTCOME MEASURES

Five questions that inquired about participants' attitudes toward MC regulation and pharmacists' roles regarding MC use.

RESULTS

Participants (n = 1343) who completed at least 1 of the 5 questions were included. The majority were aged 40-64 years (52.2%), female (69.1%), and white (88.7%). Most participants reported a history of cannabis use (81.8%) and possession or intention to apply for an MC card (52.9%). Among the conditions approved for MC use, pain (20.3%), arthritis (15.4%), and posttraumatic stress disorder (14.5%) were reported frequently. Likewise, prescription use for mood disorders (46.1%) and pain (37.4%) were also reported. In multivariable regression analyses, participants' history of cannabis use was associated with a preference for lesser oversight of MC, disagreement with MC being available through a pharmacy only, and disagreement on whether MC should be regulated before it is legalized for recreational use (all P < 0.001). It was also associated with a decrease in agreement that pharmacists are well-trained to improve patient safety (P < 0.001) and counsel patients regarding appropriate MC use (P = 0.032).

CONCLUSION

Participants who had previously used cannabis were in favor of fewer restrictions and negatively perceived pharmacists' involvement in ensuring appropriate dispensing and MC use. The findings may highlight the need for Arkansas pharmacists to explore alternative ways to promote the safe and proper MC use.

RNA-BASED DRUG SUSCEPTIBILITY TESTING OF MYCOBACTERIUM TUBERCULOSIS

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Variability in execution of the chin-down maneuver by healthy adults

OBJECTIVE

The chin-down maneuver is commonly used in dysphagia management to facilitate greater airway protection. However, the literature suggests that variation in maneuver execution may threaten the effectiveness of the intervention. Our goal was to study variation in chin-down maneuver execution given a uniform instruction.

METHODS

Sagittal view digital video recordings were acquired from 408 healthy adults who performed sequences of reiterated water swallows in head-neutral and chin-down positions. Head angle measurements were extracted from the recordings, using markers on goggles worn by 176 participants.

RESULTS

We observed considerable variation in head angle in the head-neutral swallowing task, with a trend to greater flexion in participants over the age of 65. Male participants showed greater variation in head angle than females. Head flexion during the chin-down swallowing tasks averaged 19°, in the range reported to yield clinical benefit in radiographic studies.

CONCLUSION

We conclude that a clear, uniform instruction is adequate to facilitate execution of the chin-down maneuver to a degree that is likely to be of clinical benefit. The variation in head angle observed in this study warrants further research, particularly regarding the relationship between anatomical cervical spine curvature and head angle influence on swallowing.

Antitumor activity of MDV3100 in a phase I/II study of castration-resistant prostate cancer (CRPC)

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Background: MDV3100 is a novel AR antagonist selected for activity in prostate cancer model systems with overexpressed AR. In contrast to bicalutamide, MDV3100 blocks nuclear translocation of AR and DNA binding, and has no known agonist activity when AR is overexpressed. Antitumor activity of MDV3100 in a Phase I/II trial was assessed by prostate-specific antigen (PSA), soft tissue and osseous disease, circulating tumor cells (CTC), and time on treatment. Methods: Patients (pts) with progressive CRPC were enrolled in sequential cohorts of 3–6 pts at 30, 60, 150, 240, 360, 480 and 600 mg/day. Once the safety of a dose was established, enrollment was expanded at doses >60 mg/day to include 12 chemotherapy-naïve (naïve) and 12 post-chemotherapy pts per cohort. Results: 140 pts were enrolled. 114 pts at 30–360 mg/day have been followed for >12 weeks. PSA declines (>50% from baseline) were observed at week 12 in 57% (37/65) of naïve and 45% (22/49) of post-chemo pts. Data suggest a dose-response trend particularly in post-chemo pts where PSA responses were 32% at 60 and 150 mg/day and 58% at 240 and 360 mg/day. At 12 weeks, radiographic control (no progression) was observed in 35/47 pts (74%) with evaluable soft tissue lesions per PCWG2 guidelines and 50/81 pts (62%) with bone lesions. CTC counts on 101 of 114 pts showed 92% (56/61) with favorable (<5) counts pretreatment maintained favorable posttreatment counts, while 53% (21/40) converted from unfavorable to favorable posttreatment. For post-chemo pts, favorable retention was 100% (17/17) and unfavorable to favorable conversion at 240 and 360 mg/day was 60% (6/10). 87 pts at 30–240 mg/day have been followed for >24 weeks; 35 (40%) received treatment >24 weeks. At 600 mg/day, 2 of 3 pts had dose limiting toxicity (rash; seizure). Dose reductions due to fatigue were noted at 480 and 360 mg/day. Conclusions: MDV3100 is a promising candidate for the treatment of prostate cancer assessed by PSA, imaging, CTC, and time on treatment. The data suggest a dose-response trend and consistency across endpoints. Pt follow-up is continuing. The efficacy comparable to that at higher doses and the better adverse event profile, led to the selection of 240 mg/day as the recommended dose for a phase III trial in CRPC.

[Table: see text]

Sex differences in the neuroanatomy of human mirror-neuron system: a voxel-based morphometric investigation

Females frequently perform better in empathy, interpersonal sensitivity, and emotional recognition than do males. The mirror-neuron system has been proposed to play an important role in social cognition. It remains to be clarified, however, whether the neuroanatomy underlying the human mirror neuron system exhibits sex differences. With the use of voxel-based morphometry analysis, a whole-brain unbiased technique to characterize regional cerebral volume differences in structural magnetic resonance images, concurrent with the dispositional empathy measures, we demonstrate that young adult females (n=25) had significantly larger gray matter volume in the pars opercularis and inferior parietal lobule than matched males (n=25) participants. Moreover, higher self-report scores in the emotional empathic disposition was tightly coupled with larger gray matter volume of the pars opercularis across all female and male participants (P=0.002). These results indicate that the existence of neuroanatomical sex differences in the human mirror-neuron system. They also suggest that the network of the human mirror-neuron system is strongly linked to empathy competence.

Membrane binding proteins are the major determinants for the hepatocellular transmembrane flux of long-chain fatty acids bound to albumin

PURPOSE

The hepatic transmembrane flux of long-chain fatty acids (LCFA) occurs through passive and fatty acid transport protein facilitated processes from blood. The extent that these transport processes can be related to the unbound and protein-bound fractions of LCFA in blood is not clear.

METHODS

We used hepatocyte suspensions, hepatoma monolayers, and perfused rat livers to quantitate the transport of purified [(3)H]palmitate ([(3)H]PA) and 12-(N-methyl)-N-[(7-nitrobenz-2oxa-1,3-diazol-4yl-)amino]octadecanoicacid (12-NBDS) from solutions with a constant unbound LCFA concentration with varying bovine serum albumin (BSA) concentrations and in the presence and absence of antisera raised against cytosolic liver fatty acid binding protein (L-FABP).

RESULTS

In the absence of L-FABP antisera, using an unbound ligand concentration that was adjusted to remain constant at each BSA concentration, hepatocyte [(3)H]PA and 12-NBDS uptake rates increased linearly with an increase in BSA concentration (p < 0.0001). In the presence of L-FABP antisera, [(3)H]PA uptake showed a greater reduction in the presence of 100 muM BSA than 5 muM BSA. The calculated permeability surface area product (PS) confirmed that both unbound and bound fractions of LCFA contributed to the overall flux, but only the PS for the protein-bound fraction was reduced in the presence of L-FABP antisera. In situ rat liver perfusion studies showed that the only rate process for the disposition of [(3)H]PA in the liver inhibited by L-FABP antisera was that for influx, as defined by PS, and that it reduced PS in the perfused liver by 42%.

CONCLUSION

These results suggest that, at physiological albumin concentrations, most of the LCFA uptake is mediated from that bound to albumin by a hepatocyte basolateral membrane transport protein, and uptake of unbound LCFA occurring by passive diffusion contributes a minor component.

Assessing the cellular transmembrane electrical potential difference on the hepatic uptake of palmitate

Understanding the driving forces for the hepatic uptake of endogenous and exogenous substrates in isolated cells and organs is fundamental to describing the underlying hepatic physiology/pharmacology. In this study we investigated whether uptake of plasma protein-bound [3H]-palmitate across the hepatocyte wall is governed by the transmembrane electrical potential difference (PD). Uptake was studied in isolated hepatocytes and isolated perfused rat livers (IPL). Protein-binding and vasoactive properties of the different perfusates were determined using in vitro heptane/buffer partitioning studies and the multiple indicator dilution (MID) technique in the IPL, respectively. Altering hepatocyte PD by perfusate ion substitution resulted in either a substantial depolarization (-14 +/- 1 mV, n = 12, mean +/- S.E., substituting choline for Na+) or hyperpolarization (-46 +/- 3 mV, n = 12, mean +/- S.E., substituting nitrate for Cl-). Perfusate ion substitution also affected the equilibrium binding constant for the palmitate-albumin complex. IPL studies suggested that, other than with gluconate buffer, hepatic [3H]-palmitate extraction was not affected by the buffer used, implying PD was not a determinant of extraction. [3H]-Palmitate extraction was much lower (p < 0.05) when gluconate was substituted for Cl- ion. This work contrasts with that for the extraction of [3H]-alanine where hepatic extraction fraction was significantly reduced during depolarization. Changing the albumin concentration did not affect hepatocyte PD, and [3H]-palmitate clearance into isolated hepatocytes was not affected by the buffers used. MID studies with vascular and extravascular references revealed that, with the gluconate substituted buffer, the extravascular volume possibly increased the diffusional path length thus explaining reduced [3H]-palmitate extraction fraction in the IPL.

A left-lateralized network for reading Chinese words: a 3 T fMRI study

fMRI was used to investigate brain organization for reading in Chinese. Subjects were shown two-character Chinese words. A control task was used to eliminate the non-linguistic visual and motor confounds. Results show that naming of Chinese logographs is characterized by left-lateralized neuronal networks for the processing of orthographic, phonological, and semantic attributes. The orchestration of the middle frontal cortex, superior temporal cortex, superior parietal cortex, basal temporal area and extrastriate cortices of the left hemisphere may manifest the particularity of the central representation of simple word naming in Chinese.

Syntactic priming of nouns and verbs in Chinese

Syntactic priming of Chinese nouns and verbs was investigated in word recognition (cued shadowing of auditory targets) and production (picture naming). Disyllabic compound words were presented after syntactically congruent, incongruent, or neutral auditory contexts, with a zero delay between offset of the context and onset of the target. Significant priming was observed in both tasks, including facilitation as well as inhibition. Post hoc analyses showed that reaction times were also affected by sublexical variables that are especially relevant for Chinese, including syllable density (number of word types and tokens in the language with the same first or second syllable) and semantic transparency (whether the meaning of the whole word is predictable from the separate meanings of the two syllables within the compound). These patterns suggest competitive effects at the sublexical level. Implications for interactive models of lexical access are discussed.

Dynamic localization of a cytoplasmic signal transduction response regulator controls morphogenesis during the Caulobacter cell cycle

We present evidence that a bacterial signal transduction cascade that couples morphogenesis with cell cycle progression is regulated by dynamic localization of its components. Previous studies have implicated two histidine kinases, DivJ and PleC, and the response regulator, DivK, in the regulation of morphogenesis in the dimorphic bacterium Caulobacter crescentus. Here, we show that the cytoplasmic response regulator, DivK, exhibits a dynamic, cyclical localization that culminates in asymmetric distribution of DivK within the two cell types that are characteristic of the Caulobacter cell cycle; DivK is dispersed throughout the cytoplasm of the progeny swarmer cell and is localized to the pole of the stalked cell. The membrane-bound DivJ and PleC histidine kinases, which are asymmetrically localized at the opposite poles of the predivisional cell, control the temporal and spatial localization of DivK. DivJ mediates DivK targeting to the poles whereas PleC controls its release from one of the poles at times and places that are consistent with the activities and location of DivJ and PleC in the late predivisional cell. Thus, dynamic changes in subcellular location of multiple components of a signal transduction cascade may constitute a novel mode of prokaryotic regulation to generate and maintain cellular asymmetry.

Insulin receptors and insulin action in the brain: review and clinical implications

Insulin receptors are known to be located on nerve cells in mammalian brain. The binding of insulin to dimerized receptors stimulates specialized transporter proteins that mediate the facilitated influx of glucose. However, neurons possess other mechanisms by which they obtain glucose, including transporters that are not insulin-dependent. Further, insulin receptors are unevenly distributed throughout the brain (with particularly high density in choroid plexus, olfactory bulb and regions of the striatum and cerebral cortex). Such factors imply that insulin, and insulin receptors, might have functions within the central nervous system in addition to those related to the supply of glucose. Indeed, invertebrate insulin-related peptides are synthesized in brain and serve as neurotransmitters or neuromodulators. The present review summarizes the structure, distribution and function of mammalian brain insulin receptors and the possible implications for central nervous system disorders. It is proposed that this is an under-studied subject of investigation.

Distribution of particulate matter and tissue remodeling in the human lung

We examined the relationship between intrapulmonary particle distribution of carbonaceous and mineral dusts and remodeling of the airways along anatomically distinct airway paths in the lungs of Hispanic males from the central valley of California. Lung autopsy specimens from the Fresno County Coroner's Office were prepared by intratracheal instillation of 2% glutaraldehyde at 30 cm H(2)O pressure. Two distinct airway paths into the apico-posterior and apico-anterior portions of the left upper lung lobe were followed. Tissue samples for histologic analysis were generally taken from the intrapulmonary second, fourth, sixth, and ninth airway generations. Parenchymal tissues beyond the 12th airway generation of each airway path were also analyzed. There was little evidence of visible particle accumulation in the larger conducting airways (generations 2-6), except in bronchial-associated lymphoid tissues and within peribronchial connective tissue. In contrast, terminal and respiratory bronchioles arising from each pathway revealed varying degrees of wall thickening and remodeling. Walls with marked thickening contained moderate to heavy amounts of carbonaceous and mineral dusts. Wall thickening was associated with increases in collagen and interstitial inflammatory cells, including dust-laden macrophages. These changes were significantly greater in first-generation respiratory bronchioles compared to second- and third-generation respiratory bronchioles. These findings suggest that accumulation of carbonaceous and mineral dust in the lungs is significantly affected by lung anatomy with the greatest retention in centers of lung acini. Furthermore, there is significant remodeling of this transitional zone in humans exposed to ambient particulate matter.

Intrapericardial delivery of fibroblast growth factor-2 induces neovascularization in a porcine model of chronic myocardial ischemia

Therapeutic angiogenesis is a novel approach to the treatment of myocardial ischemia based on the use of proangiogenic growth factors to induce the growth of new blood vessels to supply the myocardium at risk. This study was designed to assess the safety and efficacy of a single intrapericardial injection of basic fibroblast growth factor (FGF-2) in a porcine model of chronic myocardial ischemia. Yorkshire pigs underwent ameroid placement around the left circumflex coronary artery. At 3 weeks, animals were randomized to receive a single intrapericardial injection of either saline (n = 10), 3 mg of heparin (n = 9), 3 mg of heparin + 30 microgram of FGF-2 (n = 10), 200 microgram of FGF-2 (n = 10), or 2 mg of FGF-2 (n = 10). Coronary angiography, microsphere flow, magnetic resonance functional, and perfusion imaging were performed before and 4 weeks after treatment, at which time histologic analysis was also performed on 3 animals in each group. In ischemic pigs, FGF-2 treatment resulted in significant increases in left-to-left angiographic collaterals and left circumflex coronary artery blood flow. These benefits were accompanied by improvements in myocardial perfusion and function in the ischemic territory, as well as histologic evidence of increased myocardial vascularity without any adverse effects. Not one of these benefits was seen in saline- or heparin-treated ischemic animals. A single intrapericardial injection of FGF-2 in a porcine model of chronic myocardial ischemia results in functionally significant myocardial angiogenesis, without any adverse outcomes. This mode of FGF-2 administration may prove to be a useful therapeutic strategy for the treatment of patients with ischemic heart disease.

Intracoronary and intravenous administration of basic fibroblast growth factor: myocardial and tissue distribution

Therapeutic angiogenesis using various heparin-binding growth factors is a promising treatment for ischemic heart disease. Single dose intracoronary (IC) or i.v. delivery are most practical for clinical use. This study was designed to investigate the myocardial and tissue deposition of basic fibroblast growth factor (bFGF) after IC and i.v. administration in normal and chronically ischemic animals. Twenty-four Yorkshire pigs were used (12 normal and 12 ischemic animals) with IC and i.v. administration of 125I-bFGF (25 microCi) combined with cold bFGF (30 microg) and heparin (3 mg). Tissue and myocardial distribution was determined at 1 and 24 h by measuring 125I-bFGF specific activity and by organ and light level autoradiography. The liver accounted for the majority of 125I-bFGF activity at 1 h (37.6 +/- 17.1% for IC and 42.1 +/- 17.7% for i.v. delivery), with a reduction to 2.8 +/- 1.5% for IC and 1.5 +/- 0.9% for i.v. delivery by 24 h. Total cardiac specific activity at 1 h was 0.88 +/- 0.89% for IC and 0.26 +/- 0.08% for i.v. administration (p =.12) and decreased to 0.05 +/- 0.04% (p =.05, versus 1 h) and 0. 04 +/- 0.01% (p <.001, versus 1 h) at 24 h, respectively. IC but not i.v. delivery resulted in higher deposition in ischemic than normal myocardium. IC delivery resulted in enhanced bFGF deposition only in myocardial territories subtended by the infused artery. Intravenous delivery compares favorably with IC delivery with a 3- to 4-fold reduction in myocardial deposition at 1 h and with similar solid organ deposition. The less invasive nature of i.v. delivery, its potential for repeat administration, and its applicability to a larger population may offset its resultant reduced myocardial deposition. Efficacy studies are ongoing.

Subxyphoid access of the normal pericardium: a novel drug delivery technique

The pericardial space may potentially serve as a drug delivery reservoir that might be used to deliver therapeutic substances to the heart. This study describes a novel delivery technique that enables safe and rapid percutaneous subxyphoid access of the normal pericardium in a large animal model (49 Yorkshire pigs). An epidural introducer needle (Tuohy-17) is advanced gently under fluoroscopic guidance with a continuous positive pressure of 20-30 mm Hg (achieved by saline infusion using an intraflow system). The positive pressure is intended to push the right ventricle (with a lower pressure) away from the needle's path. Entry of the pericardial space is suspected after an increase in the saline flow through the intraflow system. Access to the pericardial space is confirmed by the injection of 1 ml of diluted contrast under fluoroscopy. A soft floppy-tip 0.025" guidewire is then advanced to the pericardial space and the needle is exchanged for an infusion catheter. Access of the pericardial space was achieved in all animals without any adverse events and without any hemodynamic compromise even with the delivery of fluid volumes as large as 50 ml. Histologic examination in 15 animals 4 weeks after pericardial access did not reveal any delivery-related myocardial damage. The safety, ease, and absence of hemodynamic compromise make this technique a potentially useful method for intrapericardial drug delivery and a good alternative to standard pericardiocentesis in patients with small pericardial effusions at higher risk for complications.

Therapeutic myocardial angiogenesis using percutaneous intrapericardial drug delivery

In this manuscript, we describe the potential role of the pericardial space as a drug delivery reservoir to administer angiogenic agents to the heart resulting in functionally significant angiogenesis with single bolus basic fibroblast growth factor (bFGF) delivery. We also describe a percutaneous subxyphoid pericardial access technique that is safe, rapid, and reliable.

Modulation of myocardial perfusion and vascular reactivity by pericardial basic fibroblast growth factor: insight into ischemia-induced reduction in endothelium-dependent vasodilatation

OBJECTIVES

The present study was designed to study the effects of a single intrapericardial injection of basic fibroblast growth factor on myocardial vascular resistance and endothelium-dependent microvascular dilatation in a porcine model of chronic myocardial ischemia and to investigate the mechanism of ischemia-induced impairment of endothelium-dependent vasodilatation.

METHODS

Yorkshire pigs underwent ameroid constrictor placement on the left circumflex coronary artery. At 3 weeks, animals were randomized to a single intrapericardial injection of saline solution (n = 10), 30 micrograms basic fibroblast growth factor (n = 10), or 2 mg basic fibroblast growth factor (n = 10). Myocardial vascular resistance in the normal (left anterior descending) and ischemic collateral-dependent (left circumflex artery) territories (using colored microspheres) and microvascular reactivity to adenosine diphosphate and sodium nitroprusside were measured before treatment and 4 weeks after treatment. The expression of inducible and endothelial nitric oxide synthase was determined in normal and ischemic myocardium by means of reverse transcriptase-polymerase chain reaction and Western analysis, and the effect of nitric oxide on endothelium-dependent vasodilatation was determined.

RESULTS

Compared with results in the control group, treatment with basic fibroblast growth factor resulted in significant improvement in left circumflex artery resistance and endothelium-dependent vasodilatation, reflecting increased collaterals. Myocardial ischemia was associated with increased expression of inducible nitric oxide synthase with no change in endothelial nitric oxide synthase. However, the nitric oxide donor sodium nitroprusside did not affect endothelium-dependent vasodilatation to adenosine diphosphate.

CONCLUSIONS

A single intrapericardial bolus of basic fibroblast growth factor may be a useful therapeutic strategy for the treatment of myocardial ischemia in patients with coronary artery disease. Although chronic myocardial ischemia is associated with increased expression of inducible nitric oxide synthase, it does not appear to be the cause of altered endothelial function.