Thrombosis in the Coronary Microvasculature Impairs Cardiac Relaxation and Induces Diastolic Dysfunction

BACKGROUND

Heart failure with preserved ejection fraction is proposed to be caused by endothelial dysfunction in cardiac microvessels. Our goal was to identify molecular and cellular mechanisms underlying the development of cardiac microvessel disease and diastolic dysfunction in the setting of type 2 diabetes.

METHODS

We used Leprdb/db (leptin receptor-deficient) female mice as a model of type 2 diabetes and heart failure with preserved ejection fraction and identified Hhipl1 (hedgehog interacting protein-like 1), which encodes for a decoy receptor for HH (hedgehog) ligands as a gene upregulated in the cardiac vascular fraction of diseased mice.

RESULTS

We then used Dhh (desert HH)-deficient mice to investigate the functional consequences of impaired HH signaling in the adult heart. We found that Dhh-deficient mice displayed increased end-diastolic pressure while left ventricular ejection fraction was comparable to that of control mice. This phenotype was associated with a reduced exercise tolerance in the treadmill test, suggesting that Dhh-deficient mice do present heart failure. At molecular and cellular levels, impaired cardiac relaxation in DhhECKO mice was associated with a significantly decreased PLN (phospholamban) phosphorylation on Thr17 (threonine 17) and an alteration of sarcomeric shortening ex vivo. Besides, as expected, Dhh-deficient mice exhibited phenotypic changes in their cardiac microvessels including a prominent prothrombotic phenotype. Importantly, aspirin therapy prevented the occurrence of both diastolic dysfunction and exercise intolerance in these mice. To confirm the critical role of thrombosis in the pathophysiology of diastolic dysfunction, we verified Leprdb/db also displays increased cardiac microvessel thrombosis. Moreover, consistently, with Dhh-deficient mice, we found that aspirin treatment decreased end-diastolic pressure and improved exercise tolerance in Leprdb/db mice.

CONCLUSIONS

Altogether, these results demonstrate that microvessel thrombosis may participate in the pathophysiology of heart failure with preserved ejection fraction.

Partial Mural Cell Ablation Disrupts Coronary Vasculature Integrity and Induces Systolic Dysfunction

Background Although the critical role of pericytes in maintaining vascular integrity has been extensively demonstrated in the brain and the retina, little is known about their role in the heart. We aim to investigate structural and functional consequences of partial pericyte depletion (≈60%) in the heart of adult mice. Methods and Results To deplete pericytes in adult mice, we used platelet-derived growth factor receptor β-Cre/ERT2; Rosa^DTA mice and compared their phenotype with that of control mice (Rosa^DTA) chosen among their littermates. Cardiac function was assessed via echocardiography and left ventricular catheterization 1 month after the first tamoxifen injection. We found mice depleted with pericytes had a reduced left ventricular ejection fraction and an increased end-diastolic pressure, demonstrating both systolic and diastolic dysfunction. Consistently, mice depleted with pericytes presented a decreased left ventricular contractility and an increased left ventricular relaxation time (dP/dt_min). At the tissue level, mice depleted of pericytes displayed increased coronary endothelium leakage and activation, which was associated with increased CD45⁺ cell infiltration. Consistent with systolic dysfunction, pericyte depletion was associated with an increased expression of myosin heavy chain 7 and decreased expression of ATPase sarcoplasmic/endoplasmic reticulum Ca2⁺ transporting 2 and connexin 43. More important, coculture assays demonstrated, for the first time, that the decreased expression of connexin 43 is likely attributable to a direct effect of pericytes on cardiomyocytes. Besides, this study reveals that cardiac pericytes may undergo strong remodeling on injury. Conclusions Cardiac pericyte depletion induces both systolic and diastolic dysfunction, suggesting that pericyte dysfunction may contribute to the occurrence of cardiac diseases.

Two-dimensional echocardiographic estimates of left ventricular volumes obtained in different views in dogs provide similar measurements but are not interchangeable

INTRODUCTION

Little information exists regarding the interchangeability of left ventricular volume estimates using a monoplane Simpson's Method of Discs on images obtained from the left apical four-chamber and right parasternal long axis four-chamber views. We examined if volume estimates obtained from these views were interchangeable.

ANIMALS

A total of 224 dogs: 86 healthy, 96 with mitral valve disease, 42 with various cardiac pathologies.

MATERIALS AND METHODS

Investigators obtained right parasternal long-axis and left apical four-chamber views from each dog and used manufacturer-supplied software to estimate left ventricular volumes in diastole and systole using Simpson's Method of Discs. Estimates based on linear measurements (diameter cubed, 0.67∗diameter cubed, and Teichholz) were also calculated. Reproducibility for each view, and agreement between the estimates obtained with each view, and those calculated from linear dimensions, were examined using Limits of Agreement. Reference intervals for volumes indexed to bodyweight and body surface area were calculated.

RESULTS

Neither method proved very reproducible. Although no bias was detected, the agreement between volumes indexed to bodyweight and body surface area was insufficient to recommend interchangeability. Estimates based on Teichholz and diameter cubed methods overestimated volumes; however, those based on 0.67∗diameter cubed performed reasonably.

CONCLUSIONS

Monoplane volume estimates from the left apical and right parasternal long axis four-chamber views are similar but not interchangeable. Clinicians can perform crude estimates of left ventricular volume using the equation 0.67∗diameter cubed.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 3. Injuries in the primary dentition. Hebrew edition]

Traumatic injuries to the primary dentition present special problems and the management is often different as compared with the permanent dentition. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialities were included in the task group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care for management of primary teeth injuries. The IADT cannot and does not guarantee favorable outcomes from strict adherence to the guidelines, but believe that their application can maximize the chances of a positive outcome. The Hebrew Edition is part of the IADT global effort to provide a worldwide accessibility to these guidelines. This third part will discuss injuries in the primary dentition.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 2. Avulsion of permanent teeth. Hebrew edition]

Avulsion of permanent teeth is one of the most serious dental injuries, and a prompt and correct emergency management is very important for the prognosis. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the task group. The guidelines represent the current best evidence and practice based on literature research and professionals' opinion. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of avulsed permanent teeth. The Hebrew Edition is part of the IADT global effort to provide a worldwide accessibility to these guidelines. This scond part of the guidelines will focus on avulsion of permanent teeth.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 1. Fractures and luxations of permanent teeth. Hebrew edition]

Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and follow up are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented. The Hebrew Edition is part of the IADT global effort to provide accessibility to these guidelines worldwide.

A randomized double-blind trial of intravenous trimetazidine as adjunctive therapy to primary angioplasty for acute myocardial infarction

BACKGROUND

Despite high patency rates, primary angioplasty for myocardial infarction does not necessarily result in optimal myocardial reperfusion and limitation of infarct size. Experimentally, trimetazidine limits infarct size, decreases platelet aggregation, and reduces leukocyte influx into the infarct zone. To assess trimetazidine as adjunctive therapy to primary angioplasty for acute myocardial infarction a prospective, double-blind, placebo-controlled pilot trial was performed.

METHODS

94 patients with acute myocardial infarction were randomized to receive trimetazidine (40 mg bolus followed by 60 mg/day intravenously for 48 h) (n=44) or placebo (n=50), starting before recanalization of the infarct vessel by primary angioplasty. Patients underwent continuous ST-segment monitoring to assess return of ST-segment deviation to baseline and presence of ST-segment exacerbation at the time of vessel recanalization. Infarct size was measured enzymatically from serial myoglobin measurements. Left ventricular angiography was performed before treatment and repeated at day 14.

RESULTS

Blinded ST segment analysis showed that despite higher initial ST deviation from baseline in the trimetazidine group (355 (32) vs. 278 (29) microV, P=0.07), there was an earlier and more marked return towards baseline within the first 6 h than in the placebo group (P=0.014) (change: 245 (30) vs. 156 (31) microV respectively, P=0.044). There was a trend towards less frequent exacerbation of ST deviation at the time of recanalization in the trimetazidine group (23.3 vs. 42.2%, P=0.11). There was no difference in left ventricular wall motion at day 14, or in enzymatic infarct size. There was no side effect from treatment. Clinical outcomes were similar between groups.

CONCLUSION

Trimetazidine was safe and led to earlier resolution of ST-segment elevation in patients treated by primary angioplasty for acute myocardial infarction.

Description of pressure ulcer pain at rest and at dressing change

PURPOSE

To describe and compare the pain experienced by patients with stage II, III, and IV pressure ulcers both at rest and during dressing change.

PATIENTS AND SETTING

Thirty-two subjects were recruited from acute, extended, and home care settings in the Midwest. The sample population ranged in age from 47 to 95 years (mean age 74.7 years, SD = 12.8), were white, and evenly divided between male and female patients.

METHODS

Patients used the McGill Pain Questionnaire to rate their pressure ulcer pain at rest and again at dressing change.

RESULTS

Twenty-eight subjects (87.5%) reported pain at dressing change and 27 (84.4%) experienced pain at rest, compared with 4 (12.5%) subjects who reported no pressure ulcer-related pain. Of the 28 reporting pain, 21 (75%) rated their pain as mild, discomforting, or distressing, and 5 (18%) described their pain as horrible or excruciating. Twelve (42%) reported their pain as continuous, occurring both at rest and during dressing changes. Despite these reports, only 2 (6%) subjects had received medication for their pressure ulcer pain. Although none of the hypotheses were statistically significant, we observed that patients with stage II, III, and IV pressure ulcers experienced pain.

CONCLUSIONS

Within this study sample, the majority of patients had pressure ulcer-related pain, which for some was severe and constant. Therefore we conclude that the potential for pressure ulcer-related pain should be anticipated and assessed on a regular basis. In addition, further research is needed to increase our understanding of pressure ulcer pain and to find effective interventions for its relief.

A simple system to determine who needs osteoporosis screening

OBJECTIVE

To define factors that identify patients at highest risk for osteoporosis who should be screened.

METHODS

We gave a questionnaire we developed for osteoporosis risk factors to 1346 menopausal women who were being screened by bone densitometry at the spine, hip, and femoral neck. Chi-square analysis using the one-tailed test was done on all categoric variables to determine differences or patterns in bone mineral density at specific sites. Multivariate logistic regression analysis was done on each of the three sites scanned to determine which combination of independent variables was a significant predictor of the presence or absence of osteoporosis.

RESULTS

Factors identified that were significant for the presence of osteoporosis were age 61 years or older, weight 165 pounds or less, or lack of any use of estrogen, either oral contraceptives or estrogen replacement therapy.

CONCLUSION

We devised a simple system to identify which patients should be screened for osteoporosis.

XBF-1, a winged helix transcription factor with dual activity, has a role in positioning neurogenesis in Xenopus competent ectoderm

Neuronal differentiation in the vertebrate nervous system is temporally and spatially controlled by mechanisms which are largely unknown. Here we investigate the role of XBF-1, an anterior neural plate-specific winged helix transcription factor, in controlling the pattern of neurogenesis in Xenopus ectoderm. We show that, in the anterior neural plate of normal embryos, prospective neurogenesis is positioned at the anterior boundary of the XBF-1 expression domain. By misexpressing XBF-1 in the posterior neural plate we show that a high dose of XBF-1 has a dual effect; it suppresses endogenous neuronal differentiation in high expressing cells and induces ectopic neuronal differentiation in adjacent cells. In contrast, a low dose of XBF-1 does not suppress but instead, expands the domain of neuronal differentiation in the lateral and ventral sides of the embryo. XBF-1 regulates the expression of XSox3, X-ngnr-1, X-Myt-1 and X-Δ-1 suggesting that it acts early in the cascade leading to neuronal differentiation. A fusion of XBF-1 to a strong repressor domain (EnR) mimics most of the XBF-1 effects suggesting that the wild type XBF-1 is a transcriptional repressor. However, fusion of XBF-1 to a strong activation domain (E1A) specifically suppresses neuronal differentiation suggesting that XBF-1 may also work as a transcriptional activator. Based on these findings, we propose that XBF-1 is involved in positioning neuronal differentiation by virtue of its concentration dependent, dual activity, as a suppressor and an activator of neurogenesis.

Case-control study of the risk factors for age related macular degeneration. France-DMLA Study Group

AIM

A case-control study was initiated to determine the risk factors for the development of age related macular degeneration (AMD).

METHODS

Study participants, who were all white, aged 50-85 years, and were recruited from private ophthalmology practices. Each practitioner enrolled patients with bilateral AMD, who were then matched with controls for sex and age. Environmental factors and systemic and ocular histories were screened. All patients had bilateral red-free fundus photographs and fluorescein angiography. Photographs were classified into pigment epithelium alterations, drusen, geographic atrophy, and exudative AMD. Statistical analysis included the identification of risk factors for AMD. A multivariate analysis was performed at the end of the study. Analysis included the entire study population and was carried out for each stage of AMD.

RESULTS

1844 controls were compared with 1844 patients with AMD. Mean age was 71 years for controls and 72 for cases. Logistic regression identified six major risk factors for AMD (whole population): arterial hypertension (odds ratio (OR) = 1.28), coronary disease (OR = 1.31), hyperopia (OR = 1.33), light coloured irises (OR = 1.22), and lens opacities or previous cataract surgery (OR = 1.55). The significance of vascular risk factors was increased for late stages of AMD, especially the atrophic forms (coronary disease, OR = 3.19).

CONCLUSIONS

This large case-control study confirms some of the risk factors previously identified and may contribute to the determination of methods for prevention of AMD.

Kzf1 - a novel KRAB zinc finger protein encoding gene expressed during rat spermatogenesis

Two novel KRAB (Krüppel associated box) type zinc finger protein encoding cDNAs, named Kzf1 and Kzf2 (Kzf for KRAB zinc finger), were identified by screening of a rat embryonic brain cDNA library with a human ZNF91 KRAB probe. Kzf1 and Kzf2 encode proteins with an amino-terminal KRAB domain and a carboxy-terminal zinc finger cluster containing 9 and 13 zinc finger units, respectively. While Kzf2 appears to be ubiquitously expressed, Kzf1 is preferentially expressed in the testis. Within the testis, Kzf1 mRNA is restricted to germ cells. The Kzf1 protein exhibits DNA binding activity and its KRAB domain can function as a repressor module in transcription. Using somatic cell hybrid analysis, the Kzf1 gene was mapped to chromosome 6.

Transcription regulation and alternative splicing of an early zygotic gene encoding two structurally distinct zinc finger proteins in Xenopus laevis

We describe the structural organization of a gene, termed XFDL 141/156, that is transiently activated during early Xenopus development. XFDL 141/156 is first transcribed at the midblastula transition (MBT) and during early gastrulation events. A roughly 200 nucleotide fragment immediately 5' to the transcription start site is sufficient for transient, early zygotic activation of gene expression. The primary transcript is subject to alternative splicing. Corresponding cDNAs encode two structurally related but completely distinct C2H2-type zinc finger proteins of unknown biological function.

X-MyT1, a Xenopus C2HC-type zinc finger protein with a regulatory function in neuronal differentiation

X-MyT1 is a C2HC-type zinc finger protein that we find to be involved in the primary selection of neuronal precursor cells in Xenopus. Expression of this gene is positively regulated by the bHLH protein X-NGNR-1 and negatively regulated by the Notch/Delta signal transduction pathway. X-MyT1 is able to promote ectopic neuronal differentiation and to confer insensitivity to lateral inhibition, but only in cooperation with bHLH transcription factors. Inhibition of X-MyT1 function inhibits normal neurogenesis as well as ectopic neurogenesis caused by overexpression of X-NGNR-1. On the basis of these findings, we suggest that X-MyT1 is a novel, essential element in the cascade of events that allows cells to escape lateral inhibition and to enter the pathway that leads to terminal neuronal differentiation.

Home documented monitoring of cardiorespiratory pattern and oxygen saturation in healthy infants

The objective of this study was to establish longitudinal normative limits for home memory monitors during early infancy. Eighty-eight healthy infants were monitored overnight at 0.25-19 wk of age using the Healthdyne Smart Monitor. Apnea settings were 14 s for recording and 40 s for alarm; the bradycardia setting was 50 beats/min (5-s delay) for both recording and alarm. Arterial oxygen saturation (SaO2) was documented whenever an event was recorded. The monitor was used 77% of all possible days; median daily use was 8.0 h. Eighty-three percent of all monitor alarms were caused by loose leads, the other 17% by false apnea or false bradycardia. Of all recorded events, 68.9% were caused by false apnea or false bradycardia; the other 31.1% were central apneas that reached the recording threshold of 14 s. The longest apnea was 36 s (wk 1); the 95th percentile for longest apnea was 19.9 s in wk 1 and 18.0 s in wk 17-19 (p < 0.001). Periodic low SaO2 values occurred with periodic breathing; the lowest value was 72%. The 5th percentiles for lowest SaO2 were 82 and 86% in wk 1 and 13-19, respectively (p < 0.001), but the minimum value observed in any week was never > 81%. The median duration of SaO2 < 90% was only 5 s but the range was wide (1-183 s), and 39/527 episodes (7.4%) were > 10 s. In summary, these longitudinal data provide the first available normal limits for cardiorespiratory pattern and SaO2 during documented home monitoring in early infancy. Utilization of these normative data will improve the diagnostic validity and clinical usefulness of event recordings.

Emergence of the ZNF91 Krüppel-associated box-containing zinc finger gene family in the last common ancestor of anthropoidea

The ZNF91 gene family, a subset of the Krüppel-associated box (KRAB)-containing group of zinc finger genes, comprises more than 40 loci; most reside on human chromosome 19p12-p13.1. We have examined the emergence and evolutionary conservation of the ZNF91 family. ZNF91 family members were detected in all species of great apes, gibbons, Old World monkeys, and New World monkeys examined but were not found in prosimians or rodents. In each species containing the ZNF91 family, the genes were clustered at one major site, on the chromosome(s) syntenic to human chromosome 19. To identify a putative "founder" gene, > 20 murine KRAB-containing zinc finger protein (ZFP) cDNAs were randomly cloned, but none showed sequence similarity to the ZNF91 genes. These observations suggest that the ZNF91 gene cluster is a derived character specific to Anthropoidea, resulting from a duplication and amplification event some 55 million years ago in the common ancestor of simians. Although the ZNF91 gene cluster is present in all simian species, the sequences of the human ZNF91 gene that confer DNA-binding specificity were conserved only in great apes, suggesting that there is not a high selective pressure to maintain the DNA targets of these proteins during evolution.

A community-based survey of infant sleep position. Pediatric Research in Office Practices Network

OBJECTIVE

To determine prevalent infant sleep positions before and after the American Academy of Pediatrics position statement of 1992 and to identify determinants of sleep position.

DESIGN

cross-sectional survey.

SETTING

private and hospital-sponsored general pediatric offices.

PARTICIPANTS

parents of infants younger than 7 months of age.

RESULTS

Eight hundred fifty-two care givers completed surveys during the 5-week study. Fifty-four percent of the study infants were put to sleep in the prone position. In 416 families with more than one child, however, 75% of the youngest siblings had been put to sleep in the prone position at the same age. Gender, race, family income, maternal smoking, and birth weight were not associated with choice of sleep position.

CONCLUSIONS

There has been a change in infant sleep positioning in the desired direction since the American Academy of Pediatrics statement. However, 54% of the study infants were still being put to sleep prone.

Frequently selected nursing diagnoses for the rehabilitation client with stroke

From 2 million to 3 million people in the United States live with the aftereffects of stroke. Nursing diagnoses provide a taxonomy that enables nurses to identify similarities and differences for given groups of clients. The purposes of this study were to identify the most frequently chosen nursing diagnoses for rehabilitation stroke clients and to determine the corresponding objective clinical characteristics (related factors) of these diagnoses. A retrospective descriptive design was used to study charts from randomly selected stroke clients (N = 100) at a large rehabilitation center. At admission and at discharge, impaired physical mobility (99%) and self-care deficit (91%) were the most frequently occurring diagnoses. Impaired physical mobility was usually related to neuromuscular impairment, and self-care deficit was usually related to neuromuscular dysfunction. These objective clinical characteristics help to determine how diagnoses are unique to rehabilitation nursing practice.

Dietary fiber nursing intervention: prevention of constipation in older adults

Constipation is a major complaint of older adults. Approximately 30% of older adults use laxatives at least once weekly, and laxatives account for 1% of physician prescriptions in addition to approximately 700 over-the-counter preparations. This study evaluated the efficacy of a fiber and fluid nursing intervention on the maintenance of bowel movements and elimination aid withdrawal in residents of a long-term health care facility. The findings indicated that the number of bowel movements reached a peak at 3 months and returned to baseline values at the 6-month point while the use of both laxatives and stool softeners decreased significantly. Enema and suppository use was so infrequent at baseline and throughout the study that changes in these variables were statistically insignificant. The results demonstrate that a natural means of maintaining bowel movements using a fiber and fluid nursing intervention can significantly decrease the number of laxatives and stool softeners needed by residents of a long-term facility.

[Denitrifying activity and generation time in 4 species of Rhizobium]

Denitrifying capacity and doubling time were measured among 44 strains of Rhizobium belonging to 4 species: B. japonicum, R. lupini, R. meliloti et R. leguminosarum. There was no correlation between doubling time and the rate of production of N2O in the presence of C2H2 in B. japonicum and R. lupini. In 38 other strains, only denitrifying capacity was measured. The percentage of strains showing denitrification capacity varied according to the species: 70% in B. japonicum, 90% in R. lupini, 37% in R. meliloti and 14% in R. leguminosarum. The strains of the latter species showed a very low level of denitrifying activity in comparison with the strains of the 3 other species.

Streptomyces K15 DD-peptidase-catalysed reactions with suicide beta-lactam carbonyl donors

The values of the kinetic parameters that govern the interactions between the Streptomyces K15 DD-peptidase and beta-lactam compounds were determined by measuring the inactivating effect that these compounds exert on the transpeptidase activity of the enzyme and, in the case of [14C]benzylpenicillin and [14C]cefoxitin, by measuring the amounts of acyl-enzyme formed during the reaction. K15 DD-peptidase binds benzylpenicillin or cefoxitin at a molar ratio of 1:1. Benzylpenicilloate is the major product released during breakdown of the acyl-enzyme formed with benzylpenicillin. Benzylpenicillin is not a better acylating agent than the amide Ac2-L-Lys-D-Ala-D-Ala and ester Ac2-L-Lys-D-Ala-D-lactatecarbonyl-donor substrates. beta-Lactam compounds possessing a methoxy group on the alpha-face of the molecule show high inactivating potency.

Recombination after protoplast fusion in the yeast Candida tropicalis

Candida tropicalis protoplasts obtained by snail enzyme treatment were induced to fuse by the use of polyethylene-glycol. Heterokaryons formed by two auxotrophic strains were selected by complementation on minimal medium. These heterokaryons were unstable and readily dissociated into their nuclear components. Under appropriate conditions, the parental nuclei of an heterokaryon fused. The homokaryon so obtained was unstable and segregated into various types of auxotrophic and prototrophic recombinants.