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PubMed2004

Evolving new genetic codes.

Although the genetic code is almost universal, natural variations exist that have caused evolutionary biologists to speculate about codon evolution. There are two predominant hypotheses that specify either a gradual (ambiguous intermediate) or stochastic (codon capture) change in the code. These hypotheses are similar to two biotechnology techniques that have been used to engineer the genetic code: a 'top down' approach, in which the whole organism is evolved for the ability to incorporate unnatural amino acids, and a 'bottom up' approach, in which aminoacyl-tRNA synthetases and their cognate tRNAs are engineered. The biotechnology experiments provide insights into natural codon evolution, and a combination of these approaches should enable the evolution of organisms that can incorporate unnatural amino acids throughout their proteomes.

Journal Article↗
PubMed2006

Bromodomain testis-specific protein is expressed in mouse oocyte and evolves faster than its ubiquitously expressed paralogs BRD2, -3, and -4.

By using in silico methods in a previous study, we identified 100 oocyte-specific genes and 150 genes, enriched in the mouse oocyte. Interestingly, approximately half of the oocyte-specific genes tend to cluster on mouse chromosomes as if they have recently duplicated during evolution. In this study, we focused our attention on mouse BRDT, which belongs to a family of four structurally related proteins characterized by two N-terminal bromodomains and one C-terminal extraterminal domain (ET domain), defining the BET family. In mammals, BRD2, -3, and -4 are ubiquitously expressed, whereas BRDT expression was shown to be restricted to the testis. We were interested to know whether there was a correlation between the evolutionary rate and the specificity of expression of these four paralogous genes. First, we show by RT-PCR and in situ hybridization that BRDT is also expressed in mouse oocyte. Moreover, phylogenetic analyses show that the BRDT germ cell-specific orthology group clearly evolves faster than its ubiquitously expressed paralogs BRD2, BRD3, and BRD4. This suggests that there is a relationship between the evolution of these four groups of orthology and their tissue specificity of expression.

Amino Acid Sequence↗
PubMed1998

The evolving costs of intracoronary stents.

BACKGROUND: As stenting practice has evolved to include greater numbers of stents and adjunctive balloon catheters per case, concern has focused on the increasing costs of equipment for the delivery of stents. METHODS AND RESULTS: To evaluate temporal changes in costs of intracoronary stenting, we examined total costs, catheterization laboratory equipment costs, equipment utilization, and nonlaboratory hospital costs for stent cases for two time periods: Period I (n = 46; 3 months in 1995 involving routine warfarin anticoagulation) and Period II (n = 129; 4 months during which warfarin was being abandoned). Overall costs declined from Period I ($11,293+/-$7672) to Period II ($9819+/-$3636) (p = 0.074). Catheterization laboratory equipment expenditures rose (Period I, $3823+/-$1394 vs Period II, $4278+/-$1533), whereas noncatheterization laboratory hospital costs declined significantly (Period I, $7281+/-$7179 vs Period II, $5560+/-$3420). The difference in costs was most notable when taking into account the deletion of warfarin anticoagulation. Costs declined by $2428 for patients in Period II in whom warfarin was not prescribed (p < 0.05 vs patients in Period I). CONCLUSIONS: We conclude that despite the increasing costs for equipment of stent cases, our overall costs of providing stents declined as warfarin anticoagulation was abandoned.

Anticoagulants↗
PubMed1999

Androgen cotherapy in menopause: evolving benefits and challenges.

The hormonal effects of estrogen and androgen were first investigated at the beginning of the twentieth century. Estrogen, which was first synthesized in the 1920s, has been shown to improve menopausal symptoms, decrease the incidence of osteoporosis, have a beneficial impact on plasma lipid profiles, probably reduce ischemic cardiovascular disease, and possibly improve cognition. In addition, retrospective studies have found a decreased incidence of Alzheimer's disease among women receiving estrogen replacement therapy compared with those not receiving this form of postmenopausal therapy. Androgen has been written about in the medical literature since 1936, when Mocquot and Moricard described its use to relieve vasomotor symptoms in postmenopausal women. During the 1940s and 1950s numerous reports appeared in the literature describing the effectiveness of estrogen-androgen combination therapy for improving the overall feeling of well-being, energy level, libido, and quality of life for postmenopausal women. Recent studies have also shown estrogen-androgen therapy to contribute to the prevention of osteoporosis and reduce serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Both historical data and evolving data support further evaluation of the use of estrogen-androgen replacement therapy in postmenopausal women.

Androgens↗
PubMed2001

Septal dissection and rupture evolved as an inferobasal pseudoaneurysm.

We report two cases of postinfarction dissecting hematoma of the interventricular septum with restrictive ventricular septal defect that evolved as an inferobasal pseudoaneurysm. The difficult anatomical pattern was assessed by two-dimensional (2-D) echocardiography with Doppler and color analysis, left ventriculography and perioperative transoesophageal echo. Because the patient had no signs of heart failure, the surgical repair was successfully delayed until the dissecting tissue became fibrotic. Problems of diagnosis, decision making and surgical management are discussed.

Aged↗
PubMed2001

Evolving strategies and improving outcomes of the modified norwood procedure: a 10-year single-institution experience.

BACKGROUND: This study reviews our 10-year experience with the modified Norwood procedure to determine its early and midterm outcomes. The focus is on the impact of evolving management strategies and accumulated institutional experience. METHODS: A modified Norwood operation was performed in 171 infants over a 10-year period. Sixty-eight percent of the infants were male, the median age at operation was 6 days (range 1 to 175 days), and the median weight was 3.3 kg (range 1.7 to 4.8 kg). The 10-year period was divided into three eras: era I; 1990 through 1993; era II; 1994 through 1997; and era III; 1998 into 2000. Outcomes and risk factors for mortality were sought. RESULTS: Hypoplastic left heart syndrome or a variant was the primary diagnosis in 118 infants (69%). The overall 5-year survival rate was 43%. Multivariate analysis revealed that only need of preoperative ventilatory support, earlier date of operation, and lower weight at operation were significant independent predictors of increased time-related mortality. Morphologic features such as a diagnosis other than hypoplastic left heart syndrome, ascending aortic size, and noncardiac anomalies were not significantly associated with an increased risk of death. The hospital survival rate for stage-one palliation in era III was 82%, significantly better than that in the preceding eras (p < 0.001). Attrition between stages one and two accounted for a 15% mortality rate among hospital survivors. CONCLUSIONS: With increasing experience and improvements in perioperative care and surgical technique, good outcomes can be expected for the first-stage modified Norwood procedure. Greater monitoring of patients in the interstage period may reduce interval mortality and improve overall survival.

Female↗
PubMed2003

Successful treatment for intraoperatively evolving acute aortic dissection in a neonate.

Acute aortic dissection is a life-threatening condition. We report the case of a neonatal one-stage correction of coarctation and hypoplastic aortic arch repair plus ventricular septal defect closure. While dissecting the head vessels after cannulation of the ascending aorta and commencing cardiopulmonary bypass, type A aortic dissection evolved. This required immediate ascending aorta and aortic arch reconstruction with coarctation of the aorta resection under hypothermic circulatory arrest. The surgical management of this rather unique situation is discussed here.

Acute Disease↗
PubMed1987

Surgical revascularization of acute evolving myocardial infarction without blood cardioplegia fails to restore postischemic function in the involved segment.

This study determines the additional protection provided by multidose hypothermic potassium blood cardioplegia over cardiopulmonary bypass alone following one hour of coronary occlusion. In 19 anesthetized dogs having an open-chest procedure, the left anterior descending coronary artery (LAD) was occluded for one hour, and this resulted in loss of active shortening in the affected zone (sonomicrometry). Cardiopulmonary bypass was established, and the dogs were divided into two groups based on the mode of reperfusion. In 10 dogs, hearts were arrested for one hour with amino acid-enhanced multi-dose blood cardioplegia; the ligatures were removed prior to the second infusion. In the 9 remaining dogs, the ligatures were removed and reperfusion was initiated with unmodified blood on total vented bypass. Both groups were reperfused for one additional hour. Postischemic levels of adenosine triphosphate (ATP) were comparable in the blood cardioplegia and bypass groups, and subendocardial levels averaged 42.8% and 45.8% of controls, respectively. Levels of creatine phosphate returned to control values. Subendocardial water content was significantly less in the blood cardioplegia hearts than the bypass hearts (79.4 +/- 0.5% vs. 81.5 +/- 0.5%; p less than .05); subendocardial water content in the blood cardioplegia group was not different from controls (78.6 +/- 0.1%). Blood cardioplegia restored significantly more fractional shortening than total vented bypass alone (39.3 +/- 9.8% vs. 6.3 +/- 9.1% of control), despite similarities in postischemic levels of ATP. We conclude that blood cardioplegia allows better myocardial salvage in the setting of evolving infarction. Therefore, attention must be directed to both the conditions (bypass, delivery pressure) and composition (cardioplegia) of reperfusion.

Adenosine Triphosphate↗
PubMed1986

Reperfusion protocol and results in 738 patients with evolving myocardial infarction.

Reperfusion is an accepted therapy for evolving myocardial infarction (MI), as successful reperfusion reduces morbidity and mortality. A team approach between the cardiologists and cardiac surgeons must be applied to achieve reperfusion within a finite time from the onset of coronary thrombosis. Analysis of 738 patients grouped them by successful reperfusion in the catheterization laboratory versus the operating room. Factors that predict wall motion recovery related to the onset of clinical symptoms, time to reperfusion, coronary anatomy, and collateral network were reviewed. Comparisons were made between patients with stable versus unstable hemodynamics and successful or unsuccessful reperfusion. Of the 738 patients, the initial attempt at reperfusion was made in the catheterization laboratory with success in 331. These patients all had primarily single-vessel disease. With multiple-vessel disease identified at catheterization, 189 patients were immediately treated by surgical reperfusion. This method also was used for an additional 72 patients in whom reperfusion could not be achieved in the catheterization laboratory. Of the entire group of 738 patients, 146 (20%) could not be reperfused. Overall mortality for the 592 patients reperfused was 4.9% compared with 17% for those who could not be reperfused. Time was critical for wall motion recovery if no collaterals were demonstrated on angiography. If collaterals were present, time to reperfusion was not critical. Wall motion recovered in 90% of the patients if the endocardial anatomy on the initial angiogram was smooth. However, if the endocardial anatomy looked mottled and irregular, less than 10% of patients had recovery of wall motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1999

Evolving surgical management for ventricular septal defect, pulmonary atresia, and major aortopulmonary collateral arteries.

BACKGROUND: The purpose of this study was to evaluate the results of various surgical modalities that have been evolving for the treatment of ventricular septal defect, pulmonary atresia, and major aortopulmonary collateral arteries. METHODS: From 1993 to May 1997, 14 patients (group 1) were treated with staged unifocalization through thoracotomies and final repair by midsternotomy. From June 1997 to February 1998, 10 patients (group 2) were treated with midsternotomy, single-stage complete unifocalization, and repair. RESULTS: In group 1, 14 patients had 21 procedures (1.5 procedures per patient), of which 3 patients (21%) had final correction. There were two deaths (14%). One patient died of blocked shunt. Another patient who had aneurysmal dilation of homograft tubes that were used for unifocalization died after final repair because of low cardiac output. In group 2, 10 patients had ten surgical procedures for complete unifocalization and 9 of 10 (90%) of them achieved final correction. One patient with low cardiac output in whom we did not close the ventricular septal defect died (10%) of suprasystemic right ventricular pressure. CONCLUSION: In single-stage complete unifocalization, more patients had final correction. It reduces the number of operations and hospitalization and hence is more cost effective than multistaged procedures.

Adolescent↗
PubMed2000

Surgical management of unstable patients in the evolving phase of acute myocardial infarction.

BACKGROUND: Acute myocardial infarction (AMI) can be treated with thrombolysis or coronary catheter intervention; surgical treatment--coronary artery bypass grafting (CABG)--is reserved for the patients in whom other procedures have failed. We performed CABG in 47 patients during the evolving phase of AMI, and analyzed their short-term and long-term results. METHODS: Preoperative, intraoperative, and postoperative data were analyzed in patients who underwent emergency CABGs for AMI between January 1, 1992, and July 31, 1998. CABGs performed more than 7 days after AMI were excluded from this study. RESULTS: The subjects were 47 patients (33 males and 14 females) with AMI who were treated by emergency CABG. Intraaortic balloon pumping was used in 44 cases and percutaneous circulatory pulmonary support was used in 3 cases. The mean interval between the onset of AMI and surgery was 27.4 +/- 27.9 hours. The mean number of bypass grafts was 3.0 +/- 1.1, and at least 1 arterial conduit was used in 45 cases (95.7%). Aortic clamp time, pump time, and operative time were 64.7 +/- 31.7, 117.3 +/- 55.2, and 313.2 +/- 84.8 minutes, respectively. IABP or percutaneous cardiopulmonary support were removed in the intensive care unit (ICU) 30.0 +/- 28.9 hours after CABG. The patients were extubated 41.4 +/- 40.5 hours after surgery, remained in ICU for 4.7 +/- 2.7 days, and were discharged from the hospital after 27.0 +/- 22.5 days. Three patients died from multiorgan failure related to postoperative sepsis, and 8 cases of major complications were observed. The actuarial 5-year survival rate of the patients treated with CABG was 83.0%. CONCLUSIONS: Surgical treatment in the unstable patients after AMI can be performed with acceptable risk. Arterial revascularization may contribute to improvement in long-term results.

Aged↗
PubMed1998

Ergonomics in consumer product evaluation: an evolving process.

As part of its commitment to empowering people to make informed consumer decisions, the Consumers' Association investigates the convenience aspects of a vast range of products, from cars to garden spades. Evaluation approaches include user trials, convenience checklists and expert appraisals. Our methodology is subject to constant review and refinement to ensure the highest levels of reliability, validity and auditability. We have a distinctive approach: our tests are designed to reflect consumer usage and to provide comparative data which is absolutely fair to all products. This paper discusses the evolving nature of that methodology within the "lifetime" of a product. Reasons for choosing each method are given as practical guidance for those involved in comparative testing.

Clinical Trials as Topic↗
PubMed2001

Vibrational spectroscopy of the oxygen-evolving complex and of manganese model compounds.

A number of molecularly specific models for the oxygen-evolving complex in photosystem II (PSII) and of manganese-substrate water intermediates that may occur in this process have been proposed recently. We summarize this work briefly. Fourier transform infrared techniques have emerged as fruitful tools to study the molecular structures of Y(Z) and the manganese complex. We discuss recent work in which mid-IR (1000-2000 cm(-1)) methods have been used in this effort. The low-frequency IR region (<1000 cm(-1)) has been more difficult to access for technical reasons, but good progress has been made in overcoming these obstacles. We update recent low-frequency work on PSII and then present a detailed summary of relevant manganese model compounds that will be of importance in understanding the emerging biological data.

Manganese↗
PubMed2001

Metallo-radical hypothesis for photoassembly of (Mn)4-cluster of photosynthetic oxygen evolving complex.

A new hypothetical mechanism is proposed for photoassembly of the (Mn)4-cluster of the photosynthetic oxygen evolving complex (OEC). In this process, a neutral radical of Y(Z) tyrosine plays a role in oxidizing Mn2+ associated with an apo-OEC, and also in abstracting a proton from a water molecule bound to the Mn2+ ion, together with D1-His190. This is in a similar fashion to the metallo-radical mechanism proposed for photosynthetic water oxidation by the (Mn)4-cluster. The model insists that a common mechanism participates in the photoassembly of the (Mn)4-cluster and the photosynthetic water oxidation.

Free Radicals↗
PubMed1998

Oxygen-evolving diatom thylakoid membranes.

Two protocols were developed that yielded purified oxygen-evolving thylakoid membranes from the diatom Cylindrotheca fusiformis. One protocol employed sonication, while the second involved French press lysis of protoplasts formed by brief culture of cells in a cation-depleted medium. Regardless of the method of cell breakage, some damage to electron transport components occurred. For preservation of both light-dependent electron transport activity and in vivo fluorescence properties, 2 M sorbitol proved to be more effective than 1 M sorbitol, regardless of the method used for cell lysis. Thylakoids purified in 2 M sorbitol using the protoplast/French press method showed the best preservation of in vivo fluorescence emission signals and Photosystem II activity with ferricyanide was completely inhibited by DCMU. Thylakoids purified in 2 M sorbitol using sonication had higher rates of Photosystem II activity with ferricyanide, but this activity was less sensitive to DCMU. Whole-chain electron transport activity was low in all preparations. This is the first report of O2 evolution and of long-wavelength fluorescence in purified thylakoids of any chromophytic alga.

Diatoms↗
PubMed2003

Oxygen-evolving enhancer protein 2 is phosphorylated by glycine-rich protein 3/wall-associated kinase 1 in Arabidopsis.

The Arabidopsis wall-associated receptor kinase, WAK1, is a member of WAK family that links the plasma membrane to the extracellular matrix. A glycine-rich secreted protein, AtGRP-3, was previously shown to regulate WAK1 functions through binding to the extracellular domain of WAK1. In this study, we sought to determine the downstream molecules of the AtGRP-3/WAK1 signaling pathway, by using two-dimensional gel electrophoresis combined with Edman sequencing and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). We report here that a chloroplast protein, oxygen-evolving enhancer protein 2 (OEE2), specifically interacts with the cytoplasmic kinase domain of WAK1 and becomes phosphorylated in an AtGRP-3-dependent manner. The phosphorylation of OEE2 is also induced in Arabidopsis by treatment with avirulent Pseudomonas syringae. Taken together, these results suggest that OEE2 activity is regulated by AtGRP-3/WAK1.

Amino Acid Sequence↗
PubMed1984

Constitutive equations of erythrocyte membrane incorporating evolving preferred configuration.

The erythrocyte membrane is modeled as a two-dimensional viscoelastic continuum that evolves under the application of stress. The present analysis of the erythrocyte membrane is motivated by the recent development of knowledge about its molecular structure. The constitutive equations proposed in the present analysis explain in a consistent manner the data on both the deformation and recovery phases of the micropipette experiment. The rheological equations of the present study are applied in a later section to the analysis of a plane membrane deformation that is quantitatively similar to the tank-treading motion of the erythrocytes in a shear field. The computations yield useful information on how the membrane viscosity becomes a more dominant feature in tank-treading motion. The material constants appearing in the proposed constitutive equations may be useful indications of the biochemical state of the membrane in health and disease.

Elasticity↗
PubMed2001

Q/R RNA editing of the AMPA receptor subunit 2 (GRIA2) transcript evolves no later than the appearance of cartilaginous fishes.

The amino acid, either a glutamine (Q) or an arginine (R), at the Q/R site of the pore-lining segment (M2) of a vertebrate AMPA receptor subunit critically influences the properties of the receptor. The R codon of the mammalian AMPA receptor subunit 2 (GRIA2) transcript is not coded by the chromosomal sequence, but is created by posttranscriptional RNA editing activities. On the other hand, the R codons of some teleost GRIA2 homologs are coded by chromosomal sequences. To elucidate the evolution of the utilization of Q/R RNA editing in modifying vertebrate GRIA2 transcripts, the GRIA2 genes of five fish species and an amphibian were studied. The putative hagfish GRIA2 homolog (hfGRIA2) encodes an R codon, whereas shark and bullfrog GRIA2 genes specify a Q codon at the genomic Q/R site. All gnathostoma GRIA2 genes possess an intron splitting the coding regions of M2 and the third hydrophobic region (M3). The intronic components required for Q/R RNA editing are preserved in all the Q-coding vertebrate GRIA2 genes but are absent from the R-coding GRIA2 genes. Interestingly, the hfGRIA2 is intronless, suggesting that hfGRIA2 is unlikely evolved from a Q/R editing-competent gene. Results of this study suggest that modification of GRIA2 transcripts by Q/R editing is most likely acquired after the separation of the Agnatha and Gnathostome.

Animals↗