Characterization of symbiont populations in life-history stages of mussels from chemosynthetic environments.

The densities of chemoautotrophic and methanotrophic symbiont morphotypes were determined in life- history stages (post-larvae, juveniles, adults) of two species of mussels (Bathymodiolus azoricus and B. heckerae) from deep-sea chemosynthetic environments (the Lucky Strike hydrothermal vent and the Blake Ridge cold seep) in the Atlantic Ocean. Both symbiont morphotypes were observed in all specimens and in the same relative proportions, regardless of life-history stage.

INSULT: a novel mutagenesis method generating high yields of closed circular mutant DNA with one primer per mutant.

INSULT, a novel method for the creation of insertions, deletions, and point mutations without subcloning, requires only one new primer per mutant, and produces circular plasmids, obviating the need for special "ultracompetent" cells. The method includes cycles of linear amplification with a thermophilic polymerase, and nick repair after each cycle with a thermophilic ligase. After production of multiple single-stranded copies of circular mutation-bearing plasmid DNA, addition of a "generic" primer followed by one or more polymerase reaction cycles generates double-stranded circular DNA bearing the desired mutation.

N-terminal control of small heat shock protein oligomerization: changes in aggregate size and chaperone-like function.

The small heat shock protein superfamily is composed of proteins from throughout the phylogenetic spectrum that are induced upon environmental stress. Their structural stability under stress derives in large part from the central region of the proteins, which forms two beta sheets held together by hydrophobic interactions and appears to be present in all superfamily members. The length, sequence, and amino acid composition of the N- and C-terminals, in contrast, are quite variable.

A single-stage polymerase-based protocol for the introduction of deletions and insertions without subcloning.

A single-stage polymerase-based procedure is described that allows extensive modifications of DNA. The version described here uses the QuikChange Site-Directed Mutagenesis System kit supplied by Stratagene. The original protocol is replaced by a single-stage method in which linear production of complementary strands is accomplished in separate single primer reactions.

Ligand, cofactor, and residue vibrations in the catalytic site of endothelial nitric oxide synthase.

A study of bovine endothelial nitric oxide synthase by Fourier transform infrared (FTIR) spectroscopy in the 1000-2500 cm(-)(1) range is reported. Binding of CO to the reduced enzyme gives two heme(II)-CO nu(C)(-)(O) stretches (1927 and 1904 cm(-)(1)) which appear to be in rapid equilibrium. Photolysis of this heme(II)-CO compound is accompanied by perturbation of the local fine structure around the catalytic site giving vibrational changes of protein backbone, substrate, amino acid residues, and cofactors, to which heme, substrate arginine, and catalytic site residues contribute.

A randomized controlled trial of stress reduction in African Americans treated for hypertension for over one year.

Background: Psychosocial stress has been implicated in the disproportionately higher rates of hypertension among African Americans. This randomized controlled trial compared the effects of two stress reduction techniques and a health education control program on hypertension during a period of 1 year in African-American men and women (N = 150, mean age 49 +/- 10 years, mean blood pressure (BP) = 142/95 mm Hg) at an urban community health center.

Methods: Interventions included 20 min twice a day of Transcendental Meditation (TM) or progressive muscle relaxation (PMR), or participation in conventional health education (HE) classes.

Bridging the workforce gap for our aging society: how to increase and improve knowledge and training. Report of an expert panel.

The healthcare workforce is currently unprepared for the increasing number of older persons and the complexities of their healthcare needs. Too few healthcare workers are adequately trained in geriatrics, and developers of educational curricula across healthcare disciplines have been slow to incorporate or require geriatric training. In April 2003, leaders in geriatrics met in Washington, D.

Fatal cerebral hemorrhage early after subclavian artery endovascular therapy.

We report a case of cerebral hyperperfusion syndrome complicated by a fatal intracranial hemorrhage as a consequence of endovascular recanalization of an occluded left subclavian artery. This entity is thought to be secondary to the failure of the normal autoregulatory mechanism controlling cerebral blood flow after recanalization. Patients at risk for this relatively rare complication are not easily identified.

The function of the small insertion in the hinge subdomain in the control of constitutive mammalian nitric-oxide synthases.

Control of nitric oxide (NO) synthesis in the constitutive nitric-oxide synthases (NOS) by calcium/calmodulin is exerted through the regulation of electron transfer from NADPH through the reductase domains. This process has been shown previously to involve the calmodulin binding site, the autoinhibitory insertion in the FMN binding domain, and the C-terminal tail. Smaller sequence elements also appear to correlate with control.

Differential activation of nitric-oxide synthase isozymes by calmodulin-troponin C chimeras.

The interactions of neuronal nitric-oxide synthase (nNOS) with calmodulin (CaM) and mutant forms of CaM, including CaM-troponin C chimeras, have been previously reported, but there has been no comparable investigation of CaM interactions with the other constitutively expressed NOS (cNOS), endothelial NOS (eNOS), or the inducible isoform (iNOS). The present study was designed to evaluate the role of the four CaM EF hands in the activation of eNOS and iNOS. To assess the role of CaM regions on aspects of enzymatic function, three distinct activities associated with NOS were measured: NADPH oxidation, cytochrome c reduction, and nitric oxide (*NO) generation as assessed by the oxyhemoglobin capture assay.

Clinical course of atrial ectopic tachycardia is age-dependent: results and treatment in children < 3 or > or =3 years of age.

Objectives: We assessed the clinical presentation, natural history, and treatment response of atrial ectopic tachycardia (AET) in children <3 years of age (group 1) compared with those > or =3 years of age (group 2).

Background: Atrial ectopic tachycardia is a common cause of chronic supraventricular tachycardia in children and can be resistant to pharmacologic therapy. Radiofrequency ablation (RFA) can eliminate AET arising from a single focus.

Thermodynamics of oxidation-reduction reactions in mammalian nitric-oxide synthase isoforms.

The three mammalian nitric-oxide synthases produce NO from arginine in a reaction requiring 3 electrons per NO, which are supplied to the catalytic center from NADPH through reductase domains incorporating FAD and FMN cofactors. The isoforms share a common reaction mechanism and requirements for reducing equivalents but differ in regulation; the endothelial and neuronal isoforms are controlled by calcium/calmodulin modulation of the electron transfer system, while the inducible isoform binds calmodulin at all physiological Ca(2+) concentrations and is always on. The thermodynamics of electron transfer through the flavin domains in all three isoforms are basically similar.

Dissociated pulmonary vein arrhythmia: incidence and characteristics.

Introduction: The incidence and characteristics of dissociated arrhythmia confined to the pulmonary vein (PV) following disconnection have not been described in a large number of patients with paroxysmal atrial fibrillation.

Methods And Results: This was a prospective study of 152 patients (29 female, mean age 51 +/- 11 years) referred for catheter ablation of drug-refractory paroxysmal atrial fibrillation. Following ostial ablation, the rate and regularity of any dissociated venous activity was analyzed with and without isoproterenol infusion (to achieve a heart rate of 120-140 beats/min).

Implantable cardioverter-defibrillator therapy for prevention of sudden death in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia.

Background: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a condition associated with the risk of sudden death (SD).

Methods And Results: We conducted a multicenter study of the impact of the implantable cardioverter-defibrillator (ICD) for prevention of SD in 132 patients (93 males and 39 females, age 40+/-15 years) with ARVC/D. Implant indications were a history of cardiac arrest in 13 patients (10%), sustained ventricular tachycardia in 82 (62%), syncope in 21 (16%), and other in 16 (12%).

Structural diversity in the small heat shock protein superfamily: control of aggregation by the N-terminal region.

The small heat shock protein superfamily, extending over all kingdoms, is characterized by a common core domain with variable N- and C-terminal extensions. The relatively hydrophobic N-terminus plays a critical role in promoting and controlling high-order aggregation, accounting for the high degree of structural variability within the superfamily. The effects of N-terminal volume on aggregation were studied using chimeric and truncated proteins.

Cardiac catheterisation in infants weighing less than 2500 grams.

Objectives: To investigate the indications for, and outcome of, cardiac catheterisation in infants weighing less than 2500 g at a single institution over an 8-year period.

Patients And Methods: We assessed all infants who were less than 2500 g at the time of cardiac catheterisation at Texas Children's Hospital from January 1993 to January 2001. Comparisons of morbidity and mortality were drawn with an equivalent number of infants of similar age weighing greater than 2500 g seen over the same period of time.

Competition and binding of arginine, imidazole, and aminoguanidine to endothelial nitric oxide synthase: aminoguanidine is a poor model for substrate, intermediate, and arginine analog inhibitor binding.

The oxygenase domains of nitric oxide synthases are unusual in that they contain at least three ligand binding sites; these correspond to the axial heme ligand position, the substrate binding site, and the pterin binding site. Ligands can occupy portions of a site or extend into regions of adjacent sites. Depending on the size, shape, and binding mode of ligands to these positions, cooperative and anticooperative interactions mediated conformationally and by binding domain overlap can be observed.

Living longer, living better: the promise of aging research.

With the increasing numbers of the population aging, we are paying close attention to the opportunities and to the challenges of growing older. The needs of an aging populace are being met with a dramatic increase in research into the biology of aging, reducing disease and disability, and behavioral and cognitive aspects of aging.

Nitric oxide synthases: domain structure and alignment in enzyme function and control.

Nitric Oxide Synthases are a family of enzymes that produce NO from arginine, oxygen and reducing power in the form of NADPH; they function as signal generators and as producers of cytotoxic levels of NO (e.g., in immune defense).

Psychosocial stress and cardiovascular disease: pathophysiological links.

The remarkable decline in cardiovascular disease (CVD) experienced in developed countries over the last 40 years appears to have abated. Currently, many CVD patients continue to show cardiac events despite optimal treatment of traditional risk factors. This evidence suggests that additional interventions, particularly those aimed at nontraditional factors, might be useful for continuing the decline.

European clinical experience with a dual chamber single pass sensing and pacing defibrillation lead.

Dual chamber ICDs are increasingly implanted nowadays, mainly to improve discrimination between supraventricular and ventricular arrhythmias but also to maintain AV synchrony in patients with bradycardia. The aim of this study was to investigate a new single pass right ventricular defibrillation lead capable of true bipolar sensing and pacing in the right atrium and integrated bipolar sensing and pacing in the right ventricle. The performance of the lead was evaluated in 57 patients (age 61 +/- 12 years; New York Heart Association 1.

Neuronal nitric oxide synthase ligand and protein vibrations at the substrate binding site. A study by FTIR.

Improvements in sensitivity and data processing of Fourier transform infrared (FTIR) spectroscopy enable it to be used to detect changes in protein structure at the atomic level. This paper reports a study of neuronal nitric oxide synthase (nNOS) by FTIR difference spectroscopy in the 1000-2500 cm(-1) range where vibrational bands of ligands, prosthetic groups, and protein and amino acid side chains are found. We have exploited the photolyzable CO compound of the ferrous heme of nNOS to produce light-induced CO photolysis difference spectra and to compare spectra after hydrogen/deuterium exchange.

Disease prevention and health promotion in the aging with a traditional system of natural medicine: Maharishi Vedic Medicine.

Objective: This review focuses on a comprehensive, sophisticated system of natural medicine that appears to hold promise for prevention of chronic diseases and disabilities, loss of independence, suffering, and health care costs often associated with "usual" aging.

Methods: The authors discuss the negative impact of usual aging on our society, with its rapidly growing percentage of elderly, and the challenge of promoting "successful aging." Emphasis is given to research literature suggesting that Maharishi Vedic Medicine (MVM) is particularly effective in retarding usual aging.

Signal sequences control gating of the protein translocation channel in a substrate-specific manner.

N-terminal signal sequences mediate targeting of nascent chains to the endoplasmic reticulum and facilitate opening of the protein translocation channel to the passage of substrate. We have assessed each of these steps for a diverse set of mammalian signals. While minimal differences were seen in their targeting function, signal sequences displayed a remarkable degree of variation in initiating nascent chain access to the lumenal environment.