Conditionally mutant animal model for investigating the invasive trophoblast cell lineage

Placental development involves coordinated expansion and differentiation of trophoblast cell lineages possessing specialized functions. Among the differentiated trophoblast cell lineages are invasive trophoblast cells, which exit the placenta and invade the uterus, where they restructure the uterine parenchyma and facilitate remodeling of uterine spiral arteries. The rat exhibits deep intrauterine trophoblast cell invasion, a feature shared with human placentation, and is also amenable to gene manipulation using genome-editing techniques. In this investigation, we generated a conditional rat model targeting the invasive trophoblast cell lineage. Prolactin family 7, subfamily b, member 1 (Prl7b1) is uniquely and abundantly expressed in the rat invasive trophoblast cell lineage. Disruption of Prl7b1 did not adversely affect placental development. We demonstrated that the Prl7b1 locus could be effectively used to drive the expression of Cre recombinase in invasive trophoblast cells. Our rat model represents a new tool for investigating candidate genes contributing to the regulation of invasive trophoblast cells and their roles in trophoblast-guided uterine spiral artery remodeling.

CONDITIONALLY MUTANT ANIMAL MODEL FOR INVESTIGATING THE INVASIVE TROPHOBLAST CELL LINEAGE

Placental development involves coordinated expansion and differentiation of trophoblast cell lineages possessing specialized functions. Among the differentiated trophoblast cell lineages are invasive trophoblast cells, which exit the placenta and invade into the uterus where they restructure the uterine parenchyma and facilitate remodeling of uterine spiral arteries. The rat exhibits deep intrauterine trophoblast cell invasion, a feature shared with human placentation, and is also amenable to gene manipulation using genome editing techniques. In this investigation, we generated a conditional rat model targeting the invasive trophoblast cell lineage. Prolactin family 7, subfamily b, member 1 ( Prl7b1 ) is uniquely and abundantly expressed in the rat invasive trophoblast cell lineage. Disruption of Prl7b1 did not adversely affect placental development. We demonstrated that the Prl7b1 locus could be effectively used to drive the expression of Cre recombinase in invasive trophoblast cells. Our rat model represents a new tool for investigating candidate genes contributing to the regulation of invasive trophoblast cells and their contributions to trophoblast-guided uterine spiral artery remodeling.

Core conserved transcriptional regulatory networks define the invasive trophoblast cell lineage

The invasive trophoblast cell lineages in rat and human share crucial responsibilities in establishing the uterine-placental interface of the hemochorial placenta. These observations have led to the rat becoming an especially useful animal model for studying hemochorial placentation. However, our understanding of similarities or differences between regulatory mechanisms governing rat and human invasive trophoblast cell populations is limited. In this study, we generated single-nucleus ATAC-seq data from gestation day 15.5 and 19.5 rat uterine-placental interface tissues, and integrated the data with single-cell RNA-seq data generated at the same stages. We determined the chromatin accessibility profiles of invasive trophoblast, natural killer, macrophage, endothelial and smooth muscle cells, and compared invasive trophoblast chromatin accessibility with extravillous trophoblast cell accessibility. In comparing chromatin accessibility profiles between species, we found similarities in patterns of gene regulation and groups of motifs enriched in accessible regions. Finally, we identified a conserved gene regulatory network in invasive trophoblast cells. Our data, findings and analysis will facilitate future studies investigating regulatory mechanisms essential for the invasive trophoblast cell lineage.

CORE CONSERVED TRANSCRIPTIONAL REGULATORY NETWORKS DEFINE THE INVASIVE TROPHOBLAST CELL LINEAGE

The invasive trophoblast cell lineage in rat and human share crucial responsibilities in establishing the uterine-placental interface of the hemochorial placenta. These observations have led to the rat becoming an especially useful animal model to study hemochorial placentation. However, our understanding of similarities or differences between regulatory mechanisms governing rat and human invasive trophoblast cell populations is limited. In this study, we generated single-nucleus (sn) ATAC-seq data from gestation day (gd) 15.5 and 19.5 rat uterine-placental interface tissues and integrated the data with single-cell RNA-seq data generated at the same stages. We determined the chromatin accessibility profiles of invasive trophoblast, natural killer, macrophage, endothelial, and smooth muscle cells, and compared invasive trophoblast chromatin accessibility to extravillous trophoblast (EVT) cell accessibility. In comparing chromatin accessibility profiles between species, we found similarities in patterns of gene regulation and groups of motifs enriched in accessible regions. Finally, we identified a conserved gene regulatory network in invasive trophoblast cells. Our data, findings and analysis will facilitate future studies investigating regulatory mechanisms essential for the invasive trophoblast cell lineage.

The AKT1-FOXO4 axis reciprocally regulates hemochorial placentation

Hemochorial placentation involves the differentiation of invasive trophoblast cells, specialized cells that possess the capacity to exit the placenta and invade into the uterus where they restructure the vasculature. Invasive trophoblast cells arise from a well-defined compartment within the placenta, referred to as the junctional zone in rat and the extravillous trophoblast cell column in human. In this study, we investigated roles for AKT1, a serine/threonine kinase, in placental development using a genome-edited/loss-of-function rat model. Disruption of AKT1 resulted in placental, fetal and postnatal growth restriction. Forkhead box O4 (Foxo4), which encodes a transcription factor and known AKT substrate, was abundantly expressed in the junctional zone and in invasive trophoblast cells of the rat placentation site. Foxo4 gene disruption using genome editing resulted in placentomegaly, including an enlarged junctional zone. AKT1 and FOXO4 regulate the expression of many of the same transcripts expressed by trophoblast cells, but in opposite directions. In summary, we have identified AKT1 and FOXO4 as part of a regulatory network that reciprocally controls critical indices of hemochorial placenta development.

PCB126 induced toxic actions on liver energy metabolism is mediated by AhR in rats

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor involved in the regulation of biological responses to more planar aromatic hydrocarbons, like TCDD. We previously described the sequence of events following exposure of male rats to a dioxin-like polychlorinated biphenyl (PCB) congener, 3,3',4,4',5-pentachlorobiphenyl (PCB126), that binds avidly to the AhR and causes various types of toxicity including metabolic syndrome, fatty liver, and disruption of energy homeostasis. The purpose of this study was, to investigate the role of AhR to mediate those toxic manifestations following sub-acute exposure to PCB126 and to examine possible sex differences in effects. For this goal, we created an AhR knockout (AhR-KO) model using CRISPR/Cas9. Comparison was made to the wild type (WT) male and female Holtzman Sprague Dawley rats. Rats were injected with a single IP dose of corn oil vehicle or 5 μmol/kg PCB126 in corn oil and necropsied after 28 days. PCB126 caused significant weight loss, reduced relative thymus weights, and increased relative liver weights in WT male and female rats, but not in AhR-KO rats. Similarly, significant pathologic changes were visible which included necrosis and regeneration in female rats, micro- and macro-vesicular hepatocellular vacuolation in males, and a paucity of glycogen in livers of both sexes in WT rats only. Hypoglycemia and lower IGF1, and reduced serum non-esterified fatty acids (NEFAs) were found in serum of both sexes of WT rats, low serum cholesterol levels only in the females, and no changes in AhR-KO rats. The expression of genes encoding enzymes related to xenobiotic metabolism (e.g. CYP1A1), gluconeogenesis, glycogenolysis, and fatty acid oxidation were unaffected in the AhR-KO rats following PCB126 exposure as opposed to WT rats where expression was significantly upregulated (PPARα, females only) or downregulated suggesting a disrupted energy homeostasis. Interestingly, Acox2, Hmgcs, G6Pase and Pc were affected in both sexes, the gluconeogenesis and glucose transporter genes Pck1, Glut2, Sds, and Crem only in male WT-PCB rats. These results show the essential role of the AhR in glycogenolysis, gluconeogenesis, and fatty acid oxidation, i.e. in the regulation of energy production and homeostasis, but also demonstrate a significant difference in the effects of PCB126 in males verses females, suggesting higher vulnerability of glucose homeostasis in males and more changes in fatty acid/lipid homeostasis in females. These differences in effects, which may apply to more/all AhR agonists, should be further analyzed to identify health risks to specific groups of highly exposed human populations.

Evaluation of Placentation and the Role of the Aryl Hydrocarbon Receptor Pathway in a Rat Model of Dioxin Exposure

BACKGROUND

Our environment is replete with chemicals that can affect embryonic and extraembryonic development. Dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are compounds affecting development through the aryl hydrocarbon receptor (AHR).

OBJECTIVES

The purpose of this investigation was to examine the effects of TCDD exposure on pregnancy and placentation and to evaluate roles for AHR and cytochrome P450 1A1 (CYP1A1) in TCDD action.

METHODS

Actions of TCDD were examined in wild-type and genome-edited rat models. Placenta phenotyping was assessed using morphological, biochemical, and molecular analyses.

RESULTS

TCDD exposures were shown to result in placental adaptations and at higher doses, pregnancy termination. Deep intrauterine endovascular trophoblast cell invasion was a prominent placentation site adaptation to TCDD. TCDD-mediated placental adaptations were dependent upon maternal AHR signaling but not upon placental or fetal AHR signaling nor the presence of a prominent AHR target, CYP1A1. At the placentation site, TCDD activated AHR signaling within endothelial cells but not trophoblast cells. Immune and trophoblast cell behaviors at the uterine-placental interface were guided by the actions of TCDD on endothelial cells.

DISCUSSION

We identified an AHR regulatory pathway in rats activated by dioxin affecting uterine and trophoblast cell dynamics and the formation of the hemochorial placenta. https://doi.org/10.1289/EHP9256.

Protective role of IL33 signaling in negative pregnancy outcomes associated with lipopolysaccharide exposure

Interleukin 33 (IL33) signaling has been implicated in the establishment and maintenance of pregnancy and in pregnancy disorders. The goal of this project was to evaluate the role of IL33 signaling in rat pregnancy. The rat possesses hemochorial placentation with deep intrauterine trophoblast invasion; features also characteristic of human placentation. We generated and characterized a germline mutant rat model for IL33 using CRISPR/Cas9 genome editing. IL33 deficient rats exhibited deficits in lung responses to an inflammatory stimulus (Sephadex G-200) and to estrogen-induced uterine eosinophilia. Female rats deficient in IL33 were fertile and exhibited pregnancy outcomes (gestation length and litter size) similar to wild-type rats. Placental weight was adversely affected by the disruption of IL33 signaling. A difference in pregnancy-dependent adaptations to lipopolysaccharide (LPS) exposure was observed between wild-type and IL33 deficient pregnancies. Pregnancy in wild-type rats treated with LPS did not differ significantly from pregnancy in vehicle-treated wild-type rats. In contrast, LPS treatment decreased fetal survival rate, fetal and placental weights, and increased fetal growth restriction in IL33 deficient rats. In summary, a new rat model for investigating IL33 signaling has been established. IL33 signaling participates in the regulation of placental development and protection against LPS-induced fetal and placental growth restriction.

Poorly controlled diabetes mellitus alters placental structure, efficiency, and plasticity

INTRODUCTION

The hemochorial placenta provides a critical barrier at the maternal-fetal interface to modulate maternal immune tolerance and enable gas and nutrient exchange between mother and conceptus. Pregnancy outcomes are adversely affected by diabetes mellitus; however, the effects of poorly controlled diabetes on placental formation, and subsequently fetal development, are not fully understood.

RESEARCH DESIGN AND METHODS

Streptozotocin was used to induce hyperglycemia in pregnant rats for the purpose of investigating the impact of poorly controlled diabetes on placental formation and fetal development. The experimental paradigm of hypoxia exposure in the pregnant rat was also used to assess properties of placental plasticity. Euglycemic and hyperglycemic rats were exposed to ambient conditions (~21% oxygen) or hypoxia (10.5% oxygen) beginning on gestation day (gd) 6.5 and sacrificed on gd 13.5. To determine whether the interaction of hyperglycemia and hypoxia was directly altering trophoblast lineage development, rat trophoblast stem (TS) cells were cultured in high glucose (25 mM) and/or exposed to low oxygen (0.5% to 1.5%).

RESULTS

Diabetes caused placentomegaly and placental malformation, decreasing placental efficiency and fetal size. Elevated glucose disrupted rat TS cell differentiation in vitro. Evidence of altered trophoblast differentiation was also observed in vivo, as hyperglycemia affected the junctional zone transcriptome and interfered with intrauterine trophoblast invasion and uterine spiral artery remodeling. When exposed to hypoxia, hyperglycemic rats showed decreased proliferation and ectoplacental cone development on gd 9.5 and complete pregnancy loss by gd 13.5. Furthermore, elevated glucose concentrations inhibited TS cell responses to hypoxia in vitro.

CONCLUSIONS

Overall, these results indicate that alterations in placental development, efficiency, and plasticity could contribute to the suboptimal fetal outcomes in offspring from pregnancies complicated by poorly controlled diabetes.

Natural killer-cell deficiency alters placental development in rats

Natural killer (NK) cells are the most prevalent leukocyte population in the uterus during early pregnancy. Natural killer cells contribute to uterine vascular (spiral artery) remodeling in preparation for the increased demand on these vessels later in pregnancy. A second wave of spiral artery modification is directed by invasive trophoblast cells. The significance of the initial wave of NK-cell-mediated vascular remodeling in species exhibiting deep trophoblast invasion such as humans and rats is not known. The purpose of this study was to generate a genetic model of NK-cell deficiency in rats, and determine the consequences of NK-cell deficiency on spiral artery remodeling and reproductive outcomes. To accomplish this task, we utilized zinc finger nuclease-mediated genome editing of the rat interleukin-15 (Il15) gene. Il15 encodes a cytokine required for NK-cell lineage development. Using this strategy, a founder rat was generated containing a frameshift deletion in Il15. Uteri of females harboring a homozygous mutation at the Il15 locus contained no detectable NK cells. NK-cell deficiency did not impact fetal growth or viability. However, NK-cell deficiency caused major structural changes to the placenta, including expansion of the junctional zone and robust, early-onset activation of invasive trophoblast-guided spiral artery remodeling. In summary, we successfully generated an NK-cell-deficient rat and showed, using this model, that NK cells dampen the extent of trophoblast invasion and delay trophoblast-directed spiral artery remodeling. This study furthers our understanding of the role of NK cells on uterine vascular remodeling, trophoblast invasion, and placental development.

Intimacy: A behavioral interpretation

This paper proposes that intimacy is a process that emerges from a sequence of events in which behavior vulnerable to interpersonal punishment is reinforced by the response of another person. These intimate events result in an increase in the probability of behavior vulnerable to interpersonal punishment in the presence of the reinforcing partner. The process results in intimate partnership formation and reports of feeling intimate. In addition to positing an operant process integrating the various components of intimacy, the theory also posits that the punishment of interpersonally vulnerable behavior is an integral aspect of intimate partnership formation and that intimate partnerships can develop that reinforce behavior that may be destructive both to the individual and to others.

The sensitivity of ecosystem carbon exchange to seasonal precipitation and woody plant encroachment

Ongoing, widespread increases in woody plant abundance in historical grasslands and savannas (woody encroachment) likely will interact with future precipitation variability to influence seasonal patterns of carbon cycling in water-limited regions. To characterize the effects of woody encroachment on the sensitivity of ecosystem carbon exchange to seasonal rainfall in a semi-arid riparian setting we used flux-duration analysis to compare 2003-growing season NEE data from a riparian grassland and shrubland. Though less seasonally variable than the grassland, shrubland NEE was more responsive to monsoon rains than anticipated. During the 2004-growing season we measured leaf gas exchange and collected leaf tissue for delta(13)C and nitrogen content analysis periodically among three size classes of the dominant woody-plant, Prosopis velutina and the dominant understory species, Sporobolus wrightii, a C(4) bunchgrass, present at the shrubland. We observed size-class and plant functional type independent patterns of seasonal plant performance consistent with greater-than-anticipated sensitivity of NEE in the shrubland. This research highlights the complex interaction between growing-season precipitation, plant-available alluvial groundwater and woody plant abundance governing ecosystem carbon balance in this semi-arid watershed.

Ventricular-vascular uncoupling increases expression of B-type natriuretic peptide in heart transplantation

BACKGROUND

Allograft adaptation to a foreign circulation is imperfect as noted from persistent limitations to stress. Effective arterial elastance (Ea), a measure of afterload, provides an estimate of aortic impedance. End systolic elastance (Ees) is a load-independent measure of ventricular performance as well as its interaction in the periphery. The ratio (Ea to Ees) characterizes ventricular-vascular coupling; a value close to unity signifies poor mechanical efficiency. The purpose of this investigation was to correlate mechanical efficiency of work with expression of B-type natriuretic peptide BNP, a specific marker of ventricular stress and strain.

METHODS

We measured BNP levels in 40 consecutive stable heart transplant recipients free from rejection. In addition, echocardiography was performed to obtain Ea, Ees, and their ratio (Ea to Ees) by the single-beat method. We examined correlates of BNP expression by assessing Ea to Ees, while correcting for mean arterial pressure, body mass index, left ventricular mass index, ejection fraction, and serum creatinine.

RESULTS

BNP levels were significantly and positively correlated (r=0.38, P=.05) with an increased Ea to Ees ratio. By multivariable analysis, this relationship persisted independently (t=2.1, P=.04), while the five other measures were insignificant predictors.

CONCLUSION

This investigation indicated that the transplanted heart demonstrates poor contractile efficiency and operates at maximal left ventricular work. This is paralleled by a tandem increase in BNP, suggesting that elevation in this stress peptide is at least partly explained by ventriculo-vascular uncoupling in heart transplantation, independent of alterations in blood pressure.

Corticosteroid weaning in the tacrolimus and mycophenolate era in heart transplantation: Clinical and neurohormonal benefits

BACKGROUND

Compared with cyclosporine, tacrolimus-based immunosuppression yields improved metabolic outcomes in heart transplantation. Whether corticosteroid freedom provides incremental metabolic benefits in tacrolimus and mycophenolate mofetil immunoprophylaxis remains uncertain.

METHODS

In a prospective trial, 41 heart transplant patients treated with tacrolimus and mycophenolate mofetil underwent steroid weaning immediately after transplantation until weaning was complete. Weaning was interrupted only for treated rejection with or without hemodynamic compromise. Benefits of steroid weaning assessed following the first year included B-type natriuretic peptide (BNP), late infections, lipids, blood pressure, hyperglycemia, and body mass index (BMI).

RESULTS

Of this 41 patient cohort (age 53 +/- 9 years, 50% black American, 35% women) followed for a total of 47 +/- 5 months, 25 had corticosteroids discontinued (62%) by an average of 20 +/- 11 months. No differences between the two groups were noted in baseline characteristics. Significant predictors of failure to wean steroids included higher rejection, BNP, and lower dose of mycophenolate mofetil. No significant benefits of steroid weaning were noted on lipids, blood pressure, hyperglycemia, and BMI. However, late infections (after 1 year) requiring hospitalizations were more frequent in the failure to wean group (0.60.4 vs 0 infections/patient/y, P <.001).

INFERENCES

Unlike known metabolic benefits of steroid withdrawal with cyclosporine, heart transplant recipients treated with tacrolimus and mycophenolate mofetil demonstrate no incremental metabolic benefits, but instead experience benefits of decreased serious late infections. Furthermore, failure to discontinue corticosteroids in this series is predicted by early allograft rejection, use of lower doses of mycophenolate mofetil, and higher BNP levels suggesting poor cardiac adaptation.

Difficult cases in heart failure. Novel diagnostic markers in heart failure: an emerging paradigm shift?

The differential diagnosis of dyspnea can be overwhelming in the presence of competing diseases. The recent advent of the peptide marker brain natriuretic peptide has ushered in an era of refined diagnostic capability in heart failure. We present a clinical scenario to illustrate the usefulness of this new biomarker assay in directing appropriate therapy for heart failure. (c)2001 CHF, Inc.

Native mitral valve regurgitation. Proactive management can improve outlook

Mitral regurgitation is a common valvular abnormality that can result in substantial morbidity. Primary care physicians should maintain a high index of suspicion for this disorder, especially in patients with symptoms of heart failure. The paramount concern is early identification of patients with mitral regurgitation and prompt referral to a cardiologist when symptoms occur or if evidence of ventricular enlargement or reduction in ejection fraction is found. Echocardiography is an invaluable tool in determining the severity of regurgitation, the integrity of the mitral valve apparatus, the extent of left ventricular enlargement, and the ejection fraction. Although no standard medical treatment has been established for mitral regurgitation, use of ACE inhibitors is appropriate. Patients presenting with severe, acute mitral regurgitation from papillary muscle rupture should be evaluated for ischemia and treated expediently. The preferred operative procedure in patients with severe mitral regurgitation and left ventricular dysfunction is mitral valve repair, if possible, or mitral valve replacement with posterior chordal preservation, if feasible.

Recurrence of giant cell myocarditis in cardiac allograft

BACKGROUND

Giant cell myocarditis causes essentially irreversible fulminant left ventricular dysfunction with associated conduction abnormalities and congestive failure. Response to immunosuppressive therapy is poor and cardiac transplantation is the only viable treatment option. The histologic hallmarks of giant cell myocarditis include a polymorphous inflammatory response with numerous multinucleated giant cells and extensive myocyte necrosis in a geographic pattern. There were 38 patients who received a cardiac transplant for giant cell myocarditis in the Giant Cell Myocarditis Registry. Among these patients, there were 9 recurrences of disease in the allograft. Concern has been expressed that recurrence of giant cell myocarditis in the allograft might be a contraindication for cardiac transplantation in the future.

METHODS

In our single-center analysis we describe the clinical and histologic findings of 5 patients transplanted for giant cell myocarditis at the Cleveland Clinic.

RESULTS

All but 1 of the patients were New York Heart Association (NYHA) class 4 with an average cardiac index (CI) of 1.52 liters/min x m(2). Of the 5 patients transplanted, 1 developed recurrent giant cell myocarditis. Routine right ventricular endomyocardial biopsy at 1 week exhibited severe multifocal myocardial fibrosis in addition to mild acute vascular rejection and mild grade 1A cellular rejection. Follow-up biopsy in this patient indicated grade IIIA moderate acute rejection in addition to multinucleated giant cells. Two distinct inflammatory processes were noted consisting of foci of T-cell inflammation identified by immunohistochemistry to be consistent with rejection, and a second inflammatory process with few mononuclear cells staining for macrophage or T-cell markers with eosinophils and myocyte necrosis consistent with giant cell myocarditis. Follow-up right ventricular endomyocardial biopsies (RVBXs) in this patient have subsequently demonstrated improvement in the degree of inflammatory infiltrate without vascular or significant cellular rejection. Vascular rejection was noted in 1 of the remaining 4 patients and was treated successfully with muramab-CD3 and plasmapheresis.

CONCLUSIONS

Giant cell myocarditis should be expected to recur in the allograft and often does so concurrently with rejection. However, the disease in the allograft responds to therapy in a favorable manner, which differs dramatically from that in the native heart. This might be the result of detection of the disease at an earlier stage than in the native heart, or the immunosuppression milieu in the allograft. The favorable response to therapy suggests that the likelihood of recurrence of giant cell myocarditis should not be considered a barrier to transplantation.

Blockage of one class of potassium channel alters the effectiveness of halothane in a brain circuit of Drosophila

At concentrations comparable to those used in the clinic, halothane has profound effects on a neuronal pathway devoted to the escape reflex of the fruit fly, Drosophila melanogaster. We studied the influence of the potassium channel that is encoded by the Shaker gene on the halothane sensitivity of this circuit. Shaker channels were specifically inactivated either by genetic means, using strains with two different severe Shaker mutations, or by pharmacologic means, using ingestion of millimolar concentrations of 4-aminopyridine. In all cases, halothane potency decreased substantially. To ensure that the genetic alteration was specific, both mutations were studied as stocks that had been repeatedly backcrossed to a control strain. The specificity of the pharmacologic inhibition was demonstrated by the fact that 4-aminopyridine had no effect on halothane potency in a Shaker mutant. Quantitative differences in the effects of channel inhibition between males and females suggested a sexual dimorphism in the functional brain anatomy of the reflex circuit.

Expression of leukemia inhibitory factor receptor mRNA in sensory dorsal root ganglion and spinal motor neurons of the neonatal rat

Previous studies have shown that the application of leukemia inhibitory factor to the proximal nerve stump prevents the degeneration of axotomized sensory neurons in the dorsal root ganglion and motor neurons in the spinal cord of newborn rats. This study investigated the expression of leukemia inhibitory factor receptor mRNA in these neurons using in situ hybridization. Leukemia inhibitory factor receptor mRNA was detected both in sensory neurons within the dorsal root ganglion and motor neurons of the cervical spinal cord. Twenty-four hours after axotomy these neurons continue to express leukemia inhibitory factor receptor mRNA. This pattern of leukemia inhibitory factor receptor expression provides a mechanism by which endogenous and exogenous leukemia inhibitory factor could act on injured sensory and motor neurons.

Evaluation of a mobile crisis program: effectiveness, efficiency, and consumer satisfaction

OBJECTIVE

The effectiveness and efficiency of a mobile crisis program in handling 911 calls identified as psychiatric emergencies were evaluated, and the satisfaction of consumers and police officers with the program was rated.

METHODS

The study retrospectively examined differences in subjects' demographic characteristics, hospitalization and arrest rates, and costs for 73 psychiatric emergency situations handled by a mobile crisis team and 58 psychiatric emergency situations handled by regular police intervention during three months in 1995. Consumers' and police officers' satisfaction with the mobile crisis program was evaluated through Likert-type scales.

RESULTS

Fifty-five percent of the emergencies handled by the mobile crisis team were managed without psychiatric hospitalization of the person in crisis, compared with 28 percent of the emergencies handled by regular police intervention, a statistically significant difference. The difference in arrest rates for persons handled by the two groups was not statistically significant. The average cost per case was 23 percent less for persons served by the mobile crisis team. Both consumers and police officers gave positive ratings to the mobile crisis program.

CONCLUSIONS

Mobile crisis programs can decrease hospitalization rates for persons in crisis and can provide cost-effective psychiatric emergency services that are favorably perceived by consumers and police officers.

Long-term outcome of cardiac allograft vasculopathy treated by transmyocardial laser revascularization: early rewards, late losses

Transmyocardial laser revascularization (TLR) was initially touted as a promising therapeutic alternative for tackling the growing problem of cardiac allograft vasculopathy in late heart transplant survivors. We first described 4- and 8-week observations of application of this surgical technique, in which we professed enthusiasm for TLR in providing symptomatic relief and in reducing ischemic burden. In this report, we present the long-term (24-month) impact of TLR on clinical outcome, channel patency, and recrudescence of ischemic burden. In the long term, surgical TLR provides neither consistent symptomatic improvement nor an ameliorative effect on the natural history of cardiac allograft vasculopathy.

A new assay for the genetic study of general anesthesia in Drosophila melanogaster: use in analysis of mutations in the X-chromosomal 12E region

We describe a new measure of the influence of general anesthetics on Drosophila that uses the robust tendency of fruit flies to briskly walk upwards after being tapped down. We expose flies to a fixed concentration of anesthetic gas in a 50 ml tube for a period of up to 1 h and then test the distribution of flies in the tube shortly after tapping them to its bottom. By measuring the effect of a series of anesthetic concentrations on the fraction of flies that fail to climb, we derive quantitative descriptors of the potency of the drug. This "distribution test" is superior to previous assays of anesthetic potency in terms of ease and reliability. We have used the assay to further the genetic analysis of several mutations that cluster on the X chromosome and are known to influence both neural function and anesthesia sensitivity. The results establish complementation patterns between the mutations, refine their genetic map positions, and open the way for the molecular identification of the relevant gene(s).

The MMPI-2 in Perú: a normative study

In this study, we compared a Peruvian normative group to the standard Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989b) U.S. normative sample. The MMPI-2 Hispanic Version was administered under standardized conditions to participants with a wide range of age, educational, occupational, and socioeconomic levels. Between the 2 samples, there was a high degree of similarity across most basic and supplementary scales. Elevations (Ts = 60-65) were found on Scale F for men and women and Scales Mf and MDS for women only. For both men and women, small elevations (Ts = 55-60) were found on several other scales. The differences were consistent with those found in other Latin American populations. The results of this study suggest that the adaptation of the MMPI-2 with the U.S. norms is appropriate for use in Perú.

Intravenous thyroid hormone supplementation in heart failure with cardiogenic shock

BACKGROUND

Thyroid hormone level abnormalities commonly exist in severe heart failure and may be of prognostic value. The therapeutic potential of using thyroid hormone for cardiogenic shock resulting from progressive heart failure has not been previously delineated. We sought to evaluate the role of an intravenous infusion of thyroxine as an adjunct to conventional inotropic agents and intra-aortic balloon counterpulsation in patients with severe heart failure with cardiogenic shock.

METHODS AND RESULTS

We studied 10 consecutive patients with severe systolic heart failure that progressed to a cardiogenic shock state unresponsive to conventional pharmacological inotropic measures. Intravenous thyroxine (20 micrograms/h) was used as an adjunctive salvage measure after the failure of conventional pharmacological and mechanical support by intra-aortic balloon pump. The invasive hemodynamic profile (right atrial pressure, pulmonary capillary wedge pressure, cardiac index, mean arterial pressure), overall clinical status, core temperature, renal function, and tachyarrhythmias were compared before and sequentially at 6, 24, and 36 hours after the initiation of thyroxine administration. Long-term outcome was also defined. All patients had statistically significant improvements in cardiac index, pulmonary capillary wedge pressure, and mean arterial pressure at 24 and 36 hours post-initiation of thyroxine. No sustained tachyarrhythmias were seen during the thyroxine infusion. In 9 of 10 patients who underwent left ventricular assist device placement and/or heart transplantation, the use of thyroxine served as an effective adjunctive measure to allow transitioning to definitive surgical therapy. The 6-month and 1-year cohort survival rates, achieved by the transition to surgical therapy, were 90% and 80%, respectively.

CONCLUSION

The beneficial hemodynamic properties of intravenous thyroid hormone can be effectively used in otherwise terminal situations of cardiogenic shock, and in such situations, the use of thyroid hormone can serve as a pharmacological adjunct to a definite surgical intervention. Further studies in larger numbers of patients might be warranted to confirm these findings.

An interview with Rick Scott. Interview by Connie R Curran

Richard (Rick) L. Scott is president and chief executive officer of Columbia/HCA Healthcare Corporation, the nation's largest health care services provider. In this interview, he discusses principles of patient care, measuring and sharing systems, the future of academic health centers, and the importance of information dissemination.

Small bowel Procardia XL tablet bezoar mimicking cystic pneumatosis intestinalis

Procardia XL Extended Release Tablets are being used with increasing frequency in the treatment of angina and hypertension. Bezoar formation, secondary to retained insoluble medication shells, is an important but less well-known complication. We report the first case of a small bowel bezoar due to this unique medication system.

Relevance of body weight to apolipoprotein levels in Australian children

OBJECTIVES

To assess weight and apolipoprotein profiles in a representative sample of primary school children.

PARTICIPANTS AND SETTING

1543 children (936 girls and 607 boys) aged 6-11 years from schools in the Eastern Sydney Area Health Service region in 1994.

METHODS

We measured body mass index (BMI) and capillary blood apolipoprotein (apo) B and A-I levels (the carrier proteins for low and high density lipoprotein cholesterol, respectively) as well as lipoprotein (Lp) (a). We related BMI levels to those documented in the 1985 Australian Council on Health, Physical Education and Recreation (ACHPER) survey of school children.

RESULTS

Compared with the ACHPER distribution, BMI was increased in the boys but not in the girls; 16.8% of boys were above the 90th percentile of the ACHPER distribution (P = 0.003) and only 6.5% were below the 10th percentile (P = 0.046). There were 45 boys (7.4%) and 53 girls (5.7%) with BMIs above the 95th percentile who were, by definition, obese. They had highly significant increases in apo B (P = 0.003) and apo B: apo A-I ratio (P = 0.0001) compared with children in the normal BMI range (10th-90th percentiles); and 20% of the population, including the obese group, also had Lp(a) levels greater than 300 mg/L. The results in children aged 10 and 11 years were not different from those of the whole group, consistent with an absence of possible confounding effects due to early puberty or smoking.

CONCLUSIONS

There was an increase in weight relative to height in boys aged 6-11 years in eastern Sydney, compared with the 1985 ACHPER survey. In both boys and girls with the highest BMI category, levels of apo B and the apo B: apo A-I ratio were significantly increased. As these apolipoprotein changes are correlated closely with early onset atherogenesis and are correctable, their identification offers prospects for prevention.

Lipoprotein alterations in the spontaneously hypertensive rat fed diets deficient in selenium and vitamin E

Both vitamin E and selenium (Se) are antioxidant nutrients that play important roles in preventing in vivo lipid peroxidation. In this investigation, Se and vitamin E were found to influence lipoprotein levels in the spontaneously hypertensive rat (SHR). Four-week-old inbred SHRs were fed a basal (B) diet with 1% cholesterol deficient in both selenium and vitamin E (B+cho diet) or identical diets to which either vitamin E (B+E+cho) or selenium (B+Se+cho) or both micronutrients were added (B+Se+E+cho). Plasma-cho and lipoprotein-cho levels were measured after 6, 12, 16, and 18 weeks of feeding the experimental diets. Rats fed the B+cho diet for at least 12 weeks had plasma-cho levels about twice that observed for rats fed the B+E+Se+cho diet. Plasma-cho levels for rats in the two Se deficient groups (B+cho and B+E+cho) were, however, similar at any time point. Se deficiency was associated with increased plasma-cho, very low density lipoprotein-cho (VLDL-cho) and low-density lipoprotein-cho (LDL-cho). Vitamin E supplementation interacted with Se deficiency to increase plasma VLDL-cho levels. Neither vitamin E alone nor the interaction between vitamin E and Se consistently influenced LDL-cho levels. The percent cholesteryl ester in LDL from rats fed the Se-deficient diets (B+cho or B+E+cho) was at least twice that observed for rats fed the B+E+Se+cho diet. Plasma lipid peroxidation products were highly elevated in rats fed the B+cho diet compared with values for the B+E+cho or the B+E+Se+cho fed rats (which were not significantly different). These results suggest that dietary Se deficiency increases plasma-cho, VLDL-cho, and LDL-cho levels by a mechanism that may be unrelated to its role as an antioxidant nutrient.

Altered hepatic catabolism of low-density lipoprotein subjected to lipid peroxidation in vitro

Recent evidence suggests that oxidatively modified forms of low-density lipoprotein (LDL) may be particularly atherogenic. In this investigation, the catabolism of human LDL modified by lipid peroxidation in vitro was studied with a recirculating rat liver perfusion system. A dual-labelling technique was used that permitted native LDL and modified LDL to be studied simultaneously in the liver perfusion system. Native human LDL was found to have a fractional catabolic rate (FCR) of 1.00 +/- 0.21%/h, in agreement with other investigators. Subjecting LDL to oxidation for 12 h in the presence of 30 microM FeEDTA did not significantly affect its FCR. LDL treated with a superoxide-generating system (xanthine oxidase, hypoxanthine, O2) in the presence of 30 microM FeEDTA did, however, show a significant increase in FCR (3.23 +/- 0.19%/h). The hepatic uptakes of native LDL and LDL oxidized with FeEDTA+O2 were similar, but both were significantly lower than the hepatic uptake of LDL treated with the superoxide-radical-generating system. The proteolysis of LDL with pancreatin did not influence either its susceptibility to oxidation or its FCR. LDL oxidation resulted in the preferential loss of alpha-tocopherol rather than gamma-tocopherol. These data indicate that the rat liver effectively catabolizes LDL oxidatively modified by treatment with the superoxide-generating system. Furthermore, our results suggest that only very low plasma levels of highly oxidized LDL could be found under conditions in vivo. The liver may therefore play a major role in protecting the arterial vasculature from highly atherogenic forms of LDL.

Somatization and malingering for workers' compensation applicants: a cross-cultural MMPI study

A post hoc analysis was conducted of 60 Hispanics and 60 Caucasians who had filed claims under workers' compensation. The study examined cross-cultural differences of somatization and malingering as assessed by the MMPI. Somatization was assessed by analyzing two- and three-point code types based on scales 1 (Hs), 2 (D), and 3 (Hy) of the MMPI, using the cut-off criterion of T > or = 70. Malingering was determined by analysis of the dissimulation index from the MMPI (F-K > +9). Significant differences were found for somatization; Hispanics were more likely to somatize. Minimal differences were found between Hispanic and Caucasian subjects on the malingering scale.

Social support of mothers of children with mental retardation

Utilization of social support and perceptions of family stress of 80 mothers with a child who had mental retardation were examined. Measures of family stress and social support were administered to subjects with a child in one of three normative transition periods. There were no significant differences in family stress scores across the groups. Analysis of variance procedures revealed significant differences in the utilization of intimate support across the age groups. Implications for further research in this area were discussed.

The role of selenium in the secretion of very-low-density lipoprotein in the isolated perfused rat liver

A recirculating liver perfusion system was used to study the effects of dietary selenium (Se) on the hepatic secretion of very-low-density lipoprotein (VLDL). The perfusate from livers of rats fed on a Se-deficient diet incorporated about 50% more [1-14C]oleic acid into triacylglycerol (TG) and cholesteryl esters (ChoEs) than did the perfusate from livers of rats fed on a Se-supplemented diet. Similarly, livers from rats fed the Se-deficient diet secreted more VLDL and incorporated about 60% more [1-14C]oleic acid into VLDL TG and ChoEs than did livers from rats fed the Se-supplemented diet. The liver perfusate from rats in the Se-deficient group also showed significantly decreased fatty acid oxidation. We conclude that Se is a potent modulator of lipoprotein metabolism. A primary action of Se deficiency appears to be a decrease in fatty acid oxidation and a stimulation of fatty acid esterification, leading to increased VLDL TG and ChoEs formation and secretion.

Postprandial glycemic response to orange juice and nondiet cola: is there a difference?

The purpose of this study was to compare the effects of unsweetened fruit juice and regular, decaffeinated soda on postprandial serum glucose levels in individuals with non-insulin-dependent diabetes mellitus (NIDDM) when these liquids are ingested separately as part of mixed meals. Eighteen individuals with NIDDM consumed three test breakfasts calculated using the diabetic exchange meal-planning system. Foods were identical in each of the breakfasts except for foods in the fruit exchange. Carbohydrate-equivalent amounts of fresh orange slices, unsweetened orange juice, and regular, decaffeinated Coke were consumed in breakfasts 1, 2, and 3, respectively. Serum glucose samples were drawn at fasting and 1, 2, and 3 hours postprandially. No difference was found in the postprandial serum glucose response when Coke versus orange juice was consumed in the breakfast. These findings question the appropriateness of using unsweetened fruit juices in routine meal planning for individuals with NIDDM.

A scanning electron microscopic study of the effect of air polishing on the enamel-sealant surface

The purpose of this study was to evaluate the enamel-sealant interface following the use of standard sealant placement techniques and an air-polishing system. Twenty-five caries-free premolars were extracted and stored in distilled water for 2 days. Five teeth were randomly assigned to each of five treatment groups. The occlusal surface was (1) air polished for 20 seconds, (2) cleaned with pumice for 20 seconds, or (3) not cleaned. Following treatment, 35% orthophosphoric acid was applied for 60 seconds. In two control groups, the acid-etching procedure was eliminated, and one group (4) was air polished for 20 seconds, while the other group (5) was not cleaned. Tinted self-curing sealant was applied to the entire occlusal surface of each tooth. Following the treatment, scanning electron photomicrographs were taken at X 1000 magnification. To evaluate the enamel-resin interface, the number of resin tags were counted by one precalibrated rater. A statistically significant difference was found among the treatment groups and the control groups. Air polishing combined with acid etching resulted in an improved surface for resin wetting as determined by the number of resin tags formed; however, the differences among the treatment groups were not large enough to be statistically significant.

Measurement characteristics of a short form of the questionnaire on resources and stress

The psychometric integrity of a short form of a measure of ecological stress was evaluated based on data provided by both fathers and mothers representing intact families, half of which included children with handicaps and half of which did not. Alpha reliability, factor structure, and construct validity analyses generally supported the conclusion that the short form of the Questionnaire on Resources and Stress is reasonably reliable and valid.

Relationship between test performance in ocular therapeutics and year of graduation

Practitioner performance on a national, standardized examination in ocular therapeutics was analyzed. The majority of the practitioners were from one state and had graduated from the same college of optometry. The homogeneity of their background fostered an analysis of the relationship between year of graduation and test performance. The data indicated that less recent graduates did not perform as well as more recent graduates, but that the best performance was attained by practitioners with considerable clinical experience.

The role of antioxidant nutrients in preventing hyperbaric oxygen damage to the retina

Vitamin E and selenium play essential roles in preventing in vivo lipid peroxidation and free radical damage. Hyperbaric oxygen (HBO) treatment adversely affected the electroretinograms (ERGs) of rats fed a diet deficient in both vitamin E and selenium (the basal or B diet) or a diet deficient in vitamin E alone (B + Se diet). After 4 weeks of HBO treatment (3.0 ATA or 100% oxygen, 1.5 hours per day, 5 day/week) rats fed the B diet deficient in vitamin E and selenium for 6 weeks showed decreased (p less than 0.05) a-wave amplitudes, 85 +/- 9 microvolts (microV), n = 11, compared with a-waves recorded (150 +/- 10 microV, n = 21) for age matched rats fed an identical diet for 6 weeks but not treated with HBO. After 15 weeks of HBO treatment, rats fed the B + Se diet deficient in vitamin E alone showed decreased (p less than 0.01) a-wave (61 +/- 9 microV, n = 4) and b-wave (253 +/- 23 microV, n = 4) amplitudes compared with a-wave (115 +/- 7 microV, n = 4) and b-wave amplitudes (450 +/- 35 microV, n = 4) for age matched rats fed the same diet but not treated with HBO. Decreased a- or b-wave amplitudes provide evidence of retinal damage. Rats fed a diet supplemented with vitamin E and selenium or vitamin E alone showed no decreases in either a- or b-wave amplitudes after 15 weeks of HBO treatment.

Quality assurance review: improving diagnostic accuracy of percutaneous needle biopsy

Adequate pathologic slide preparation of percutaneous fine-needle biopsy (PFNB) specimens is necessary to maximize sensitivity and yield a tissue diagnosis. We present a quality control review of our biopsy technique and results in 71 aspiration biopsies done in 59 patients. Immediate cytology slide preparation in the radiology suite enabled us to increase our diagnostic yield from 53% to 84%, and allowed us to preserve PFNB, rather than open biopsy, as the primary diagnostic modality. We recommend regular review of biopsy techniques to confirm adequate diagnostic yields of these procedures.