From seed to seed: the role of photoreceptors in Arabidopsis development

As sessile organisms, plants have evolved a multitude of developmental responses to cope with the ever-changing environmental conditions that challenge the plant throughout its life cycle. Of the many environmental cues that regulate plant development, light is probably the most important. From determining the developmental pattern of the emerging seedling, to influencing the organization of organelles to best maximize energy available for photosynthesis, light has dramatic effects on development during all stages of plant life. In plants, three classes of photoreceptors that mediate light perception have been characterized at the molecular level. The phytochromes recognize light in the red portion of the spectrum, while cryptochromes and phototropins perceive blue and UVA light. In this review, we discuss the different aspects of development that are regulated by these photoreceptors in the model plant species Arabidopsis thaliana and how the phytochromes, cryptochromes, and phototropins bring about changes in development seen in the growing plant.

Coordination of plastid and nuclear gene expression

The coordinated expression of genes distributed between the nuclear and plastid genomes is essential for the assembly of functional chloroplasts. Although the nucleus has a pre-eminent role in controlling chloroplast biogenesis, there is considerable evidence that the expression of nuclear genes encoding photosynthesis-related proteins is regulated by signals from plastids. Perturbation of several plastid-located processes, by inhibitors or in mutants, leads to decreased transcription of a set of nuclear photosynthesis-related genes. Characterization of arabidopsis gun (genomes uncoupled) mutants, which express nuclear genes in the presence of norflurazon or lincomycin, has provided evidence for two separate signalling pathways, one involving tetrapyrrole biosynthesis intermediates and the other requiring plastid protein synthesis. In addition, perturbation of photosynthetic electron transfer produces at least two different redox signals, as part of the acclimation to altered light conditions. The recognition of multiple plastid signals requires a reconsideration of the mechanisms of regulation of transcription of nuclear genes encoding photosynthesis-related proteins.

Multiple plastid signals regulate the expression of the pea plastocyanin gene in pea and transgenic tobacco plants

The expression of nuclear genes encoding photosynthesis-related proteins is regulated by signals from plastids. To investigate how the pea PetE gene encoding plastocyanin is regulated by plastid signals, the effects of norflurazon, lincomycin and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), specific inhibitors of plastid-located processes generating plastid signals, have been examined. RNA-gel blot analysis of 7-day-old pea and tobacco seedlings containing the pea PetE gene showed that treatment with norflurazon and lincomycin, but not DCMU, decreased the accumulation of transcripts of pea PetE and endogenous Lhcb1 genes. Analysis of chimeric PetE gene constructs in tobacco seedlings showed that an intact PetE mRNA 5' terminus and elements within the PetE coding region were required to confer sensitivity to norflurazon and lincomycin, suggesting post-transcriptional regulation. Analysis of 4-week-old tobacco plants containing chimeric PetE constructs showed that DCMU treatment decreased the accumulation of pea PetE and Lhcb1 transcripts, but had opposite effects on the transcription of the genes in nuclear run-on assays. DCMU upregulated transcription from the pea PetE promoter whereas transcription of tobacco Lhcb1 genes was decreased. These experiments provide evidence for multiple plastid signals operating at different developmental stages and affecting transcriptional and post-transcriptional processes regulating expression of the pea PetE gene.

Use of autologous blood as part of the perfusate for cardiopulmonary bypass: a priming technique

In an attempt to replace the oncotic and protein coating capabilities of serum albumin in the perfusate, we established a priming protocol that used autologous blood as part of the perfusate solution. Prior to March 1, 1999, our standard priming protocol was 1650 ml of crystalloid with 250 ml of 5% serum albumin and 5,000 units of heparin. After removing albumin from our prime, our standard protocol was altered to include 40 ml of the patient's autologous blood in 1,800 ml of crystalloid and 10,000 units of heparin. To determine the intraoperative effects of using albumin/crystalloid primes (Group A), autologous blood/crystalloid primes (Group B) and crystalloid primes (Group C), a total of 178 patients were sequentially evaluated. Intraoperative parameters evaluated were total protein (TP), colloid osmotic pressure (COP), platelets (Plts) and fluid requirements during cardiopulmonary bypass (CPB). During an overlapping 12-month period of time, 1,092 consecutive cardiac surgical cases using CPB (584 albumin prime; 508 autologous blood prime) were evaluated for clinical outcomes in terms of mortality and length of hospitalization. In addition, over a period of 15 months, 1,458 patients in both the autologous blood/crystalloid group and the crystalloid only group were evaluated for the incidence of high-pressure excursions (HPE) after going on bypass. Comparative reviews of TP, COP and Plts demonstrated no significant difference 10 min after the start of bypass between Groups A and B. However, in Group C, there was a statistically significant increase in the intraoperative fluid requirements during CPB, compared to both of the other groups. There was no significant difference in the incidence of HPE, with an occurrence of 1.04% in the crystalloid only group and 1.11% in the autologous blood/crystalloid group. Autologous blood perfusates were identical to albumin perfusates in their platelet protection and reduction of fluid shifts during the intraoperative period.

Tissue-specific, light-regulated and plastid-regulated expression of the single-copy nuclear gene encoding the chloroplast Rieske FeS protein of Arabidopsis thaliana

The single-copy PetC gene encoding the chloroplast Rieske FeS protein of Arabidopsis thaliana consists of five exons interrupted by four introns and encodes a protein of 229 amino acid residues with extensive sequence similarity to the chloroplast Rieske proteins of other higher plants. The N-terminal 50 amino acid residues constitute a presequence for targeting to the chloroplast and the remaining 179 amino acid residues make up the mature protein. Three of the introns are in identical positions in the PetC gene of Chlamydomonas reinhardtii, suggesting that they are of ancient origin. RNA-blot hybridisation showed that the gene was expressed in shoots, but not roots, and was light regulated and repressed by sucrose. The expression of chimeric genes consisting of PetC promoter fragments fused to the beta-glucuronidase (GUS) reporter gene was examined in A. thaliana and tobacco. In A. thaliana, GUS activity was detected in leaves, stems, flowers and siliques, but not in roots, and showed a strong correlation with the presence of chloroplasts. In transgenic tobacco, low levels of GUS activity were also detected in light-exposed roots. GUS activity in transgenic tobacco seedlings was light regulated and was decreased by norflurazon in the light suggesting regulation of PetC expression by plastid signals.

Preoperative prediction of prolonged mechanical ventilation following coronary artery bypass grafting

OBJECTIVE

Few studies have attempted to evaluate who would require prolonged mechanical ventilation following heart surgery. The objectives of this study were to identify predictors of prolonged ventilation in a large group of coronary artery bypass grafting (CABG) patients from a single institution.

METHODS

One thousand, eight hundred and twenty-nine consecutive patients undergoing CABG were reviewed retrospectively and evaluated for preoperative predictors of prolonged ventilation which included: age, gender, ejection fraction (EF), renal function, diabetes, angina status, New York Heart Association Class, number of diseased vessels, urgency of the procedure, re-operation, chronic lung disease (COPD) and intraoperative variables such as IABP, inotropes, stroke and myocardial infarction. Prolonged ventilation was defined as > or = 24 h. Stepwise logistic regression analysis was performed.

RESULTS

Patients were on average 65.4+/-10.6 years of age, 30% were diabetic, 80% had triple vessel disease and 93% were of functional class III/IV. The mean ejection fraction was 60+/-16 percent. Overall peri-operative mortality was 2.7%. There were 157 patients that required prolonged ventilation with a peri-operative mortality of 18.5% (P < 0.001). Preoperative independent predictors of prolonged ventilation were found to be: unstable angina (OR 5.6), EF < 50 (OR 2.3), COPD (OR 2.0), preop. renal failure (OR 1.9), female gender (OR 1.8) and age > 70 (OR 1.7). Based on these predictors, a model was created to estimate of the risk of prolonged ventilation in individual patients following CABG with results ranging from < or = 3% in patients without any risk factors to > or = 32% in patients with five or more independent risk factors. Certain intraoperative variables were strong predictors of prolonged ventilation and included: stroke (OR 12.3), re-operation for bleeding (OR 6.9) and perioperative MI (OR 5.8).

CONCLUSION

We were able to create a stable model where several preoperative and intra-operative variables were shown to be predictive of prolonged ventilation after CABG surgery. The ability to identify patients at increased risk for prolonged ventilation may allow the development of pre-emptive strategies and more effective resource allocation.

A plastid envelope location of Arabidopsis ent-kaurene oxidase links the plastid and endoplasmic reticulum steps of the gibberellin biosynthesis pathway

We have used fusions of gibberellin biosynthesis enzymes to green fluorescent protein (GFP) to determine the subcellular localization of the early steps of the pathway. Gibberellin biosynthesis from geranylgeranyl diphosphate is catalysed by enzymes of the terpene cyclase, cytochrome P450 mono-oxygenase and 2-oxoglutarate-dependent dioxygenase classes. We show that the N-terminal pre-sequences of the Arabidopsis thaliana terpene cyclases copalyl diphosphate synthase (AtCPS1) and ent-kaurene synthase (AtKS1) direct GFP to chloroplasts in transient assays following microprojectile bombardment of tobacco leaves. The AtKS1-GFP fusion is also imported by isolated pea chloroplasts. The N-terminal portion of the cytochrome P450 protein ent-kaurene oxidase (AtKO1) directs GFP to chloroplasts in tobacco leaf transient assays. Chloroplast import assays with 35S-labelled AtKO1 protein show that it is targeted to the outer face of the chloroplast envelope. The leader sequences of the two ent-kaurenoic acid oxidases (AtKAO1 and AtKAO2) from Arabidopsis direct GFP to the endoplasmic reticulum. These data suggest that the AtKO1 protein links the plastid- and endoplasmic reticulum-located steps of the gibberellin biosynthesis pathway by association with the outer envelope of the plastid.

Waiting for cardiac surgery: results of a risk-stratified queuing process

BACKGROUND

The Queen Elizabeth II Health Sciences Centre uses a weekly peer-review conference of cardiovascular experts to prioritize each surgical case to 1 of 4 queues with the use of standardized criteria of coronary anatomy, stress test result, and symptoms. We examined the hazard of waiting as well as the impact of waiting on surgical outcomes.

METHODS AND RESULTS

Analysis was performed for 2102 consecutive patients queued for CABG, aortic valve replacement, or CABG+aortic valve replacement between January 1, 1998, and December 31, 1999. Among 1854 patients undergoing surgery, median waiting times on the respective queues were as follows: in-house urgent group, 8 days; semiurgent A group, 37 days; semiurgent B group, 64 days; and elective group, 113 days. There were 13 deaths (12 cardiac) that occurred during the waiting period (0.7% of the patients). Of the 8.7% patients upgraded to a more urgent queue, 86.1% required hospitalization before surgery. Although female sex was not associated with prolonged waiting time, it was predictive of urgent status (P=0.001). The incidence of postoperative complications was 25.0%, and operative mortality was 2.86%. Both were more frequent among patients undergoing surgery early (P=0.01); however, this difference was attributable to the in-house urgent queue. The median length of stay was 7 days for all patients and was not affected by waiting time.

CONCLUSIONS

Death and upgrades while the patients were waiting tended to occur early in the queuing process, and prolonged waiting was not associated with worse surgical outcomes. The cost of reducing waiting times could in part be offset by prevention of hospital admissions among upgraded patients.

Fas ligand/Fas-mediated apoptosis in human coronary artery smooth muscle cells: therapeutic implications of fratricidal mode of action

OBJECTIVE

This study aimed to determine the mode of action of Fas ligand (FasL)/Fas at mediating apoptosis so as to evaluate the potential of FasL in gene therapy for restenosis.

METHODS

Passaged human coronary artery smooth muscle (HCASM) cells were infected with recombinant adenoviral vectors expressing murine FasL. Various parameters of FasL expression and apoptosis were measured using FACS, immunofluorescence, calorimetric, and cytotoxicity assays.

RESULTS

Most HCASM cells under normal growth conditions expressed Fas and were shown to be susceptible to membrane bound but not soluble FasL. However, some FasL expressing cells survived for up to 7 days. These surviving cells were observed to be spatially distributed and were not in direct physical contact with each other. Upon examination, it was determined that although the majority of the surviving cells expressed FasL, only 30% expressed both Fas and FasL. These cells were capable of inducing apoptosis of target cells and some were also susceptible to FasL expressing cells, provided that the effector and target cells were in close physical contact. FasL/Fas-mediated apoptosis was inhibited by p35, a baculovirus gene that inhibits caspases. Additionally, in contrast to HCASM cells, neither membrane-bound nor soluble FasL induced apoptosis in coronary artery endothelial cells.

CONCLUSIONS

FasL expressing HCASM cells do not undergo FasL/Fas mediated "suicide" but kill neighboring cells bearing Fas in a "fratricidal" manner. A small population of HCASM cells expresses no surface Fas. These results imply that HCASM cells transduced in vivo with FasL may serve as "scavengers" and exert a bystander effect on surrounding cells that may be enhanced by co-expression of p35. As FasL-mediated apoptosis occurs in coronary arterial smooth muscle but not endothelial cells, FasL may also offer an advantage over other genes for use in restenosis since the latter may indiscriminately delay re-endothelialization at the sites of gene.

Myocardial scintigraphy correlates poorly with coronary angiography in the screening of transplant arteriosclerosis

BACKGROUND

Coronary angiography remains an important screening tool for transplant coronary arteriosclerosis (TxCAD) after heart transplantation despite criticism that it underestimates the incidence of TxCAD. In an effort to improve TxCAD incidence estimation, several methods of screening have been proposed. In the present study, the incidence of TxCAD assessed by both yearly coronary angiography and stress myocardial scintigraphy imaging was reviewed.

PATIENTS AND METHODS

Ninety-nine consecutive primary heart transplantations were performed from 1988 to 1999. The standard immunosuppression protocol consisted of the introduction of antilymphocyte globulin and steroids, while maintenance therapy was with cyclosporine, imuran and steroids. Coronary angiography and a stress 2-methoxyisobutyl-isonitrile perfusion scan were performed yearly. TxCAD was defined by angiographic evidence of luminal abnormality by catheterization, or a perfusion abnormality at rest or after stress on myocardial scintigraphy.

RESULTS

The mean recipient age was 49+/-12 years and the mean donor age was 33+/-13 years. The etiology of heart failure was ischemic cardiomyopathy (50%), dilated cardiomyopathy (41%) and congenital heart disease (9%). The freedom from angiographic TxCAD was 92% at one year, 64% at five years and 35% at eight years. The freedom from nuclear imaging TxCAD was 92% at one year, 69% at five years and 44% at eight years. However, a diagnosis of TxCAD by angiography only correlated with a diagnosis of TxCAD by nuclear imaging 52.8% of the time in the same patient, with a median time between studies of one month.

CONCLUSION

The overall incidence of TxCAD diagnosed by angiography and nuclear imaging appears similar but correlates poorly in patients, casting doubt on the routine use of myocardial scintigraphy for screening TxCAD.

Pregnancy-specific enhancement of agonist-stimulated ERK-1/2 signaling in uterine artery endothelial cells increases Ca(2+) sensitivity of endothelial nitric oxide synthase as well as cytosolic phospholipase A(2)

Uterine artery endothelial cells (UAEC) from pregnant ewes (P-UAEC) demonstrate generally enhanced ability to couple growth factor and G protein-coupled receptors to the ERK-1/2 signaling pathway and stimulate NO production independently of elevated [Ca(2+)]. Herein we investigate the signaling and vasodilator responses to ATP, an agonist that also elevates [Ca(2+)](i) in both NP and P-UAEC, to determine the relative importance of Ca(2+) vs. ERK-1/2 in the activation of eNOS. We observed in both NP-UAEC and P-UAEC that ATP acts through G protein-coupled P(2Y) receptors to activate phospholipase C and dose-dependently elevate [Ca(2+)](i) independently of extracellular Ca(2+). The small reduction in the [Ca(2+)](i) response in NP vs. P-UAEC did not, however, account for the difference in NO production by P-UAEC>>NP-UAEC. ATP had no stimulatory effect on Akt phosphorylation but rapidly stimulated ERK-1/2 phosphorylation in P-UAEC>>NP-UAEC in a manner that correlated with NO production. In both NP- and P-UAEC, both ERK-1/2 and Ca(2+) were absolutely required for eNOS as well as cPLA(2) activation and the Ca(2+) sensitivity of eNOS was enhanced through the cytosolic [Ca(2+)](i) range in P-UAEC>>NP-UAEC. Thus ERK-1/2 may regulate the Ca(2+) sensitivity of eNOS to an even greater extent than is known to occur for cPLA(2).

Medtronic Intact porcine bioprosthesis experience to twelve years

BACKGROUND

The Medtronic Intact porcine bioprosthesis was further evaluated to determine the influence of zero-pressure glutaraldehyde fixation on structural valve deterioration (SVD).

METHODS

From 1986 through 1996, at three Canadian centers, 1,272 patients had 1,296 procedures: 836 aortic valve replacement (AVR), 332 mitral valve replacement (MVR), 14 tricuspid valve replacement, 3 pulmonary valve replacement, and 111 multiple valve replacements. The mean age of the patient population was 67 years (range 9 to 91 years). The total follow-up was 8,011 patient-years (mean 6.2 years).

RESULTS

The late mortality (overall) was 4.8% and 6.7% per patient-year for AVR with or without concomitant procedures, respectively; and 4.7% and 10.4% per patient-year for MVR, respectively. There were 51 cases of SVD (AVR 22 of 836; MVR 23 of 332; pulmonary valve replacement 1 of 3; and multiple valve replacement 5 of 111). The actuarial freedom from SVD at 12 years for AVR was 94.3%+/-3.3% for patients aged 61 to 70 years and 97.7%+/-1.1% for those more than 70 years; for MVR actuarial freedom from SVD at 12 years was 93.7%+/-3.9% for patients more than 70 years. The actual freedom at 12 years from SVD for AVR was 92.4%+/-3.1% for patients aged 51 to 60 years, 96.1%+/-2.1% for those 61 to 70 years, and 98.4%+/-0.7% for those older than 70 years; for MVR actual freedom from SVD at 12 years was 89.6%+/-3.2% for patients 61 to 70 years and 96.6%+/-3.4% for those more than 70 years.

CONCLUSIONS

The Medtronic Intact porcine bioprosthesis, formulated with tissue preservation at zero-pressure fixation, has encouraging freedom from structural failure.

Medtronic Mosaic porcine bioprosthesis: midterm investigational trial results

BACKGROUND

The midterm clinical and hemodynamic performance of the Medtronic Mosaic porcine bioprosthesis was evaluated in a regulatory trial.

METHODS

In nine Canadian centers, 802 bioprostheses (560 aortic and 242 mitral) were implanted between September 1994 and April 1999 in patients with a mean age of 70 years.

RESULTS

Survival for aortic valve replacement at 4 years was 84.4%+/-3.1%. Freedom from valve-related or unexplained death was 95.6%+/-1.9%; structural valve deterioration, 100.0%; reoperation, 96.2%+/-1.7%; major thromboembolism, 96.1%+/-1.8%; and major antithrombotic-related hemorrhage, 96.4%+/-1.7%. Echocardiographic derived mean systolic gradient was 13.4 mm Hg at 4 years with an indexed effective orifice area of 0.7 to 0.8 cm2/m2. A significant decrease in left ventricular mass was shown over time in all valve sizes. Survival for mitral valve replacement at 4 years was 79.2%+/-6.8%. Freedom from valve-related or unexplained death was 96.5%+/-3.4%; structural valve deterioration, 100%; reoperation, 97.0%+/-3.2%; major thromboembolism, 95.7%+/-3.8%; and major antithrombotic-related hemorrhage, 95.0%+/-4.2%. Echocardiographically measured averaged mean diastolic gradient was 4.5 mm Hg.

CONCLUSIONS

The Medtronic Mosaic bioprosthesis is safe and effective in both the aortic and mitral positions. The valve has low gradients in both positions and excellent left ventricular mass regression in the patients with aortic valve replacement.

Endothelial vasodilator production by uterine and systemic arteries. VI. Ovarian and pregnancy effects on eNOS and NO(x)

Normal pregnancy and the follicular phase of the ovarian cycle are both estrogen-dominated physiological states that are characterized by elevations in uterine blood flow and endothelial nitric oxide synthase (eNOS) protein expression in the uterine artery (UA) endothelium. It is unknown if elevations in mRNA level account for the changes in protein or eNOS activity. We tested the hypothesis that pregnancy and the follicular phase are associated with increases in eNOS mRNA and the consequent elevated expression of eNOS protein results in increased circulating nitric oxide (NO) levels. UA were obtained from pregnant (PREG; n = 8; 110-130 days gestation; term = 145 +/- 3 days), nonpregnant luteal (LUT; n = 6), nonpregnant follicular (FOL; n = 6), and nonpregnant ovariectomized (OVEX; n = 6) sheep. Circulating NO levels were analyzed as total NO(2)-NO(3) (NO(x)). Western analysis performed on UA endothelial-isolated proteins demonstrated that eNOS protein levels were OVEX = LUT < or = FOL < PREG (P < 0.05), whereas eNOS mRNA expression (RT-PCR) in UA endothelial cells obtained by limited collagenase digestion was OVEX < LUT < FOL < PREG (P < 0.05). Pregnancy dramatically elevated eNOS protein (4.1- to 6.9-fold) and mRNA (2.4- to 6.9-fold) over LUT controls (P < 0.01). Circulating NO(x) levels were not altered by ovariectomy or the ovarian cycle but were elevated from 4.4 +/- 1.1 microM in LUT to 12 +/- 4, 22 +/- 3, and 41 +/- 3 microM at 110, 120, and 130 days gestation (P < 0.01). Systemic NO(x) levels in singleton (12.5 +/- 1.6 microM) were less (P < 0.01) than in multiple (twin 27.6 +/- 6.5 microM; triplet = 46 +/- 10 microM) pregnancies. Therefore, the follicular phase and, to a much greater extent, pregnancy are associated with elevations in UA endothelium-derived eNOS expression, although significant increases in systemic NO(x) levels were only observed in the PREG group (multiple > singleton). Thus, although UA endothelial increases in eNOS protein and mRNA levels are associated with high estrogen states, increases in local UA NO production may require additional eNOS protein activation to play its important role in the maintenance of uterine blood flow in pregnancy.

Recombinant human acid alpha-glucosidase enzyme therapy for infantile glycogen storage disease type II: results of a phase I/II clinical trial

PURPOSE

Infantile glycogen storage disease type II (GSD-II) is a fatal genetic muscle disorder caused by deficiency of acid alpha-glucosidase (GAA). The purpose of this study was to investigate the safety and efficacy of recombinant human GAA (rhGAA) enzyme therapy for this fatal disorder.

METHODS

The study was designed as a phase I/II, open-label, single-dose study of rhGAA infused intravenously twice weekly in three infants with infantile GSD-II. rhGAA used in this study was purified from genetically engineered Chinese hamster ovary (CHO) cells overproducing GAA. Adverse effects and efficacy of rhGAA upon cardiac, pulmonary, neurologic, and motor functions were evaluated during 1 year of the trial period. The primary end point assessed was heart failure-free survival at 1 year of age. This was based on historical control data that virtually all patients died of cardiac failure by 1 year of age.

RESULTS

The results of more than 250 infusions showed that rhGAA was generally well tolerated. Steady decreases in heart size and maintenance of normal cardiac function for more than 1 year were observed in all three infants. These infants have well passed the critical age of 1 year (currently 16, 18, and 22 months old) and continue to have normal cardiac function. Improvements of skeletal muscle functions were also noted; one patient showed marked improvement and currently has normal muscle tone and strength as well as normal neurologic and Denver developmental evaluations. Muscle biopsies confirmed that dramatic reductions in glycogen accumulation had occurred after rhGAA treatment in this patient.

CONCLUSIONS

This phase I/II first study of recombinant human GAA derived from CHO cells showed that rhGAA is capable of improving cardiac and skeletal muscle functions in infantile GSD-II patients. Further study will be needed to assess the overall potential of this therapy.

Longitudinal study of the carrier testing process for fragile X syndrome: perceptions and coping

This paper reports the results of a longitudinal study of women at-risk to inherit the fragile X mutation. It addresses 1) how upsetting the women perceived their carrier information to be, 2) how serious a problem they perceive fragile X syndrome to be, and 3) descriptions of feelings about the carrier testing process. The study sample consisted of 42 women (20 carriers and 22 noncarriers). There were two measurement times (just prior to carrier testing and after learning actual carrier status). The measures used were a Fragile X Visual Analog Scale and a structured interview. At time 1, being at-risk was reported to be upsetting and fragile X syndrome was perceived to be a serious problem. For the women found to be carriers there was no change from time 1 to time 2 on any of the items. Significant change occurred in the non-carriers. They were significantly less upset at time 2 after receiving the results of their carrier test than at time 1. They also perceived fragile X syndrome to be a more serious problem than they did at time 1 and a more serious problem than the carriers at time 2. Themes found included concerns that carrier status for fragile X syndrome presented a barrier for having healthy biological children and concern for children's and grandchildren's adaptation to their own carrier status. Coping behaviors were activated to manage the emotions related to these concerns. The coping behaviors identified were minimization, acceptance of the possibility of being a carrier, a sense of being able to deal with the outcome of the carrier test, positive comparison, problem solving, and positive interpretation.

Adenoviral vector expressing ICP47 inhibits adenovirus-specific cytotoxic T lymphocytes in nonhuman primates

Studies from several laboratories have shown that administration of E1-deleted Ad vectors results only in transient transgene expression in the lungs of immunocompetent animals. This is due, at least in part, to destruction of vector-transduced cells by host cellular immune responses (predominantly CD8(+) CTLs) directed against viral proteins and/or immunogenic transgene products. We have previously demonstrated that E1-deleted Ad vectors can lead to persistent expression of human cystic fibrosis transmembrane conductance regulator (hCFTR) in the lungs of several strains of immunocompetent mice, despite the presence of Ad-specific CTLs. However, we found that these same vectors gave rise only to transient hCFTR expression in the lungs of rhesus monkeys. We have constructed new Ad vectors that coexpress both hCFTR and the ICP47 gene from herpes simplex virus. ICP47 has been shown to inhibit the transporter associated with antigen presentation, thus blocking major histocompatibility antigen I (MHC class I)-mediated antigen presentation to CD8(+) T cells. The Ad/hCFTR/ICP47 vector decreased levels of cell-surface MHC class I molecules on infected monkey and human cell lines. Similar results were obtained with primary human cells and primary monkey airway epithelial cells. In vitro studies showed that the Ad/hCFTR/ICP47 vector decreased cytolysis by both monkey and human CTLs. When Ad/hCFTR/ICP47 was administered to the lungs of rhesus monkeys, it inhibited the generation of Ad-specific CTLs. However, natural killer cell activity was enhanced in monkeys treated with the Ad/hCFTR/ICP47 vector.

The pea light-independent photomorphogenesis1 mutant results from partial duplication of COP1 generating an internal promoter and producing two distinct transcripts

The pea lip1 (light-independent photomorphogenesis1) mutant shows many of the characteristics of light-grown development when grown in continuous darkness. To investigate the identity of LIP1, cDNAs encoding the pea homolog of COP1, a repressor of photomorphogenesis identified in Arabidopsis, were isolated from wild-type and lip1 pea seedlings. lip1 seedlings contained a wild-type COP1 transcript as well as a larger COP1' transcript that contained an internal in-frame duplication of 894 bp. The COP1' transcript segregated with the lip1 phenotype in F(2) seedlings and could be translated in vitro to produce a protein of approximately 100 kD. The COP1 gene in lip1 peas contained a 7.5-kb duplication, consisting of exons 1 to 7 of the wild-type sequence, located 2.5 kb upstream of a region of genomic DNA identical to the wild-type COP1 DNA sequence. Transcription and splicing of the mutant COP1 gene was predicted to produce the COP1' transcript, whereas transcription from an internal promoter in the 2.5-kb region of DNA located between the duplicated regions of COP1 would produce the wild-type COP1 transcript. The presence of small quantities of wild-type COP1 transcripts may reduce the severity of the phenotype produced by the mutated COP1' protein. The genomic DNA sequences of the COP1 gene from wild-type and lip1 peas and the cDNA sequences of COP1 and COP1' transcripts have been submitted to the EMBL database under the EMBL accession numbers AJ276591, AJ276592, AJ289773, and AJ289774, respectively.

Financial viability, medical technology, and hospital closures

Informed investments in medical technology and information systems are associated with the financial viability of community hospitals. Financially distressed facilities are 3 to 4 years behind proactive hospitals in supporting high-speed data, voice, and image transmissions to physicians in various locations. Impact of the Balanced Budget Act of 1997, fraud and abuse activities, Y2K issues, and lack of information systems support for physicians will result in 800 hospital closures and mergers of distressed hospitals over the next 60 months. These findings are based on the application of an eight-step framework for classifying information systems in health care entities. This framework is validated by survey instruments, site visits, interviews with senior management in 44 health care entities containing 576 hospitals, and judgments on the financial status of the health care entities.

Carrier testing in fragile X syndrome: effect on self-concept

The purpose of the study was to explore self-concept in women at risk for inheriting the fragile X mutation. Time 1 measures were obtained prior to carrier testing and Time 2 measures were collected approximately 5 months after learning carrier status. The sample consisted of 42 women from 17 families. Measures included the Tennessee Self-Concept Scale (TSCS), the fragile X Visual Analog Scale (VAS), and a structured interview. The TSCS provided a global measure of self-concept and the fragile X VAS and structured interview provided a contextual measure of self related to carrier status. Results indicated that there were no differences initially between carriers and noncarriers and no change from Time 1 to Time 2 on the TSCS. Analysis of the Time 1 fragile X VAS means for the total sample found a reduction in positive feelings about self. Analysis of the Time 2 fragile X VAS found that noncarriers reported improvement in feelings about self, with no change in feelings about self found in the carriers. Responses from the structured interview indicated that the feelings regarding self in the context of genetic testing are not related to global self-concept, but result from concerns regarding the implications of a positive carrier test for themselves and their families. This information highlights areas related to carrier testing that warrant further investigation and may ultimately result in modifications to the genetic counseling.

Endothelial vasodilator production by uterine and systemic arteries. V. Effects of ovariectomy, the ovarian cycle, and pregnancy on prostacyclin synthase expression

Prostacyclin (PGI(2)) is a potent vasodilator, the level of which is increased during pregnancy, and is the main eicosanoid of which production is elevated in the endothelium and vascular smooth muscle (VSM) of both uterine and omental (systemic) arteries. We tested the hypothesis that during physiologic states that have high uterine blood flow, such as pregnancy and the follicular phase of the ovarian cycle (versus luteal phase and ovariectomized ewes), there is an increased level of prostacyclin synthase (PGIS) expression in ovine uterine and omental artery endothelium and VSM. To investigate this, the cellular localization and PGIS protein expression level in uterine and systemic arteries was examined by immunohistochemistry as well as by Western immunoblot analysis of endothelial-isolated protein and denuded vessels (VSM). Whole uterine, but not omental (systemic), arteries from the pregnant ewes showed an increase (P < 0.001) in PGIS expression. Further localization of PGIS protein by immunohistochemistry and quantification by Western analysis showed PGIS to be somewhat higher in the uterine artery VSM (69 +/- 7%) than endothelium (31 +/- 7%). PGIS protein levels in uterine and omental artery endothelial isolated protein were not altered by ovariectomy or the ovarian cycle, although they were both significantly elevated by pregnancy. Uterine and omental artery VSM PGIS expression levels also were not altered by ovariectomy or the ovarian cycle, whereas PGIS expression, in uterine but not omental artery VSM showed a significant elevation during pregnancy. Thus, the rise in PGI(2) production by uterine arteries observed in ovine pregnancy is paralleled by an elevation in PGIS expression in both endothelium and VSM, whereas those seen in omental arteries is associated with increases in endothelial PGIS.

Pregnancy-dependent changes in cell signaling underlie changes in differential control of vasodilator production in uterine artery endothelial cells

During pregnancy, the uterine vasculature shows a marked increase in vasodilator production [prostacyclin (PGI2) and nitric oxide (NO)] in response to a number of agonists including angiotensin II (AII) and ATP. As a consequence vascular resistance is kept low, and uterine blood flow is maximized to meet the needs of the growing fetus. Studies of the molecular basis underlying this change in control of endothelial NO and PGI2 production have been hampered by the lack of availability of a suitable cell model. To that end we have developed and characterized a new ovine uterine artery endothelial cell (UAEC) culture model derived from nonpregnant (NP) or pregnant (P) ewes. Endothelial cells were isolated from pregnant (120-130 days; n = 6) and nonpregnant (n = 4) ewes and maintained in primary culture. Endothelial cells at passage 4 showed uniform expression of endothelial nitric oxide synthase (eNOS; an endothelial marker) as well as AII type 1 receptor and growth factor receptors and uniform uptake of acetylated low density lipoprotein (a property of endothelial cells not shared by fibroblasts or vascular smooth muscle cells), thus demonstrating cell purity. Expressions of eNOS, cyclooxygenase-1, PGI2 synthase, cytosolic phospholipase A2, AII type 1 receptor, and growth factor receptors are also maintained at passage 4. Mitogenesis is maintained in response to basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and vascular endothelial growth factor (VEGF) in both NP-UAEC and P-UAEC. The differential production of vasodilators by NP-UAEC and P-UAEC is maintained in a manner similar to that previously reported in vivo. Thus, P-UAEC make NO in response to AII, ATP, bFGF, EGF, and VEGF, whereas NP-UAEC make NO in response to bFGF, EGF, and VEGF only. Similarly, P-UAEC make PGI2 in response to AII, ATP, bFGF, and VEGF, whereas NP-UAEC make PGI2 only in response to ATP and VEGF. As both cytosolic phospholipase A2 and eNOS may be regulated by both Ca2+ and protein kinases, we investigated the effects of these agonists on Ca2+ mobilization and ERK-1/2 phosphorylation. ATP consistently elevates Ca2+ levels in both P-UAEC and NP-UAEC. All other agonists were without acute (0-4 min) effect on Ca2+ in P-UAEC or NP-UAEC. In contrast, all agonists stimulated an acute (10 min) phosphorylation of ERK-1/2 in P-UAEC, whereas only EGF stimulated activation in NP-UAEC. P-UAEC production of PGI2 by agonists of both heptahelical receptors and growth factor receptors correlates closely with ERK-2 phosphorylation alone. For NO, this correlation holds for heptahelical receptor agonists, but additional signaling pathways are also implicated for bFGF and VEGF. In contrast, in NP-UAEC the lack of ERK-2 phosphorylation in response to all agonists other than EGF, and the dissociation between NO or PGI2 production and ERK-2 phosphorylation suggest that alternate pathways play a predominant role.

Differential expression of an estrogen receptor messenger RNA containing exon 1' sequences in MCF-7 breast cancer cell line stocks

The presence of an exon 1' sequence in the estrogen receptor alpha (ERalpha) mRNA was detected in different stocks of ER-positive MCF-7 human breast cancer cells by reverse transcriptase polymerase chain reaction (RT-PCR) and ribonuclease protection analysis (RPA), but not by Northern blot analysis. This mRNA, however, was not detectable in ERalpha-positive ZR-75-1 or ERalpha-negative MDA-MB-231 breast cancer cells, suggesting that exon 1' ER mRNA is differentially expressed in some but not all ER-positive cell lines, and then, only at very low levels.