Optical coherence tomography: an introduction to the technique and its use.

This report describes the new optical imaging technique of optical coherence tomography (OCT). OCT is capable of high-resolution, micrometer-scale, cross-sectional imaging of biological tissue. The OCT for ophthalmic application uses 843-nm, near-infrared light, which produces a longitudinal resolution of 10 to 20 microm and a penetration depth of a few millimeters.

Reliability and validity of screening instruments for drug and alcohol abuse in adults seeking evaluation for attention-deficit/hyperactivity disorder.

A growing number of adults are seeking evaluation for Attention-Deficit/Hyperactivity Disorder (ADHD). Screening for substance use disorders should be included as part of any comprehensive ADHD evaluation. We describe the validity and reliability of the Drug Abuse Screening Test (DAST) and the Alcohol Use Disorders Identification Test (AUDIT) in adults seeking evaluation for ADHD.

Coma outcome prediction using event-related potentials: P(3) and mismatch negativity.

The prediction of the outcome from coma is of considerable importance to the patients, their relatives and attendant medical staff, and yet current clinical methods lack sensitivity and specificity. Objective investigations can enhance the accuracy of such predictions and are an important adjuvant when reaching decisions to continue or terminate life support. Of the neurophysiological methods available, electroencephalography and short-latency somatosensory evoked potentials have proved the most useful in the clinical setting.

The repeatability of discrete and continuous anterior segment grading scales.

Purpose: To investigate the repeatability of three anterior segment clinical grading scales: 1) verbal descriptors scale (VDS), 2) photographic matching scale (PS), and 3) continuous matching scale (CS).

Methods: Five optometrists graded 30 slides each of 3-9-o'clock staining, bulbar redness, and palpebral conjunctival roughness twice, separated by at least a day. VDS and PS were five-point scales (0-4) with half grades permitted.

Ultrasonically guided transvaginal oocyte recovery from calves treated with or without GnRH.

We investigated the effect of GnRH given after gonadotropin stimulation on follicle growth and oocyte quality in young calves in a transvaginal oocyte recovery program. A 60 mg MPA pessary was inserted into each of nineteen 5-mo-old Friesian calves for 7 d; on Day 5 they received 140 mg, s.c.

Cardio-respiratory responses to rowing ergometry and treadmill exercise soon after myocardial infarction.

Purpose: The aim of this study was to compare the cardio-respiratory differences between rowing ergometry and treadmill exercise in beta-blocked men participating in exercise rehabilitation soon after myocardial infarction (postMI).

Methods: Eleven males all receiving beta-blockade medication were measured for oxygen consumption (VO2), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) at individualized submaximal exercise target heart rates (THR) during 6 min of exercise on each of a motorized treadmill and a rowing ergometer 2-6 wk (4.9 +/- 1.

Sympathetic swelling response of the control eye to soft lenses in the other eye.

Purpose: To compare central corneal swelling and light scatter after 8 hours of sleep in eyes wearing high- and low-Dk hydrogel lenses and to the contralateral control eyes.

Methods: Twenty neophyte subjects wore a Lotrafilcon A (Dk, 140; Ciba Vision, Duluth GA) silicone hydrogel lens and an Etafilcon A (Dk, 18; Acuvue; Vistakon, Jacksonville, FL) 58% water content hydrogel lens of similar center thickness in random order in the right eye only, for overnight 8-hour periods. The contralateral nonwearing left eyes served as controls.

A noncontact pneumatic esthesiometer for measurement of ocular sensitivity: a preliminary report.

Purpose: The aim of this investigation was to evaluate a prototype noncontact pneumatic esthesiometer for measuring sensitivity of the eye.

Methods: To evaluate the instrument's repeatability, central corneal sensitivity was recorded on two separate occasions with a 24-h interval between the two measures. In a separate experiment, corneal edema was induced with a thick hydrogel lens, and the eye was closed and patched.

Hydrogel lens dehydration and subjective comfort and dryness ratings in symptomatic and asymptomatic contact lens wearers.

Purpose: To determine whether lens dehydration correlates with discomfort, dryness, and noninvasive tear break-up time in symptomatic and asymptomatic contact lens wearers and whether dehydration of the two lens types varies.

Method: Twenty hydrogel contact lens wearers with dryness-related symptoms and 20 asymptomatic wearers wore an Etafilcon A lens (Acuvue; Vistakon, Inc., Jacksonville, Florida) in one eye and an Omafilcon A lens (Proclear; Biocompatibles, Norfolk, Virginia) in the contralateral eye for 7 h in a randomized, double-masked study.

A chain initiation factor common to both modular and aromatic polyketide synthases.

Antibiotic-producing polyketide synthases (PKSs) are enzymes responsible for the biosynthesis in Streptomyces and related filamentous bacteria of a remarkably broad range of bioactive metabolites, including antitumour aromatic compounds such as mithramycin and macrolide antibiotics such as erythromycin. The molecular basis for the selection of the starter unit on aromatic PKSs is unknown. Here we show that a component of aromatic PKS, previously named 'chain-length factor', is a factor required for polyketide chain initiation and that this factor has decarboxylase activity towards malonyl-ACP (acyl carrier protein).

Analysis of the pathway structure of metabolic networks.

Metabolic networks comprise a multitude of enzymatic reactions carrying out various functions related to cell growth and product formation. Although such reactions are occasionally organized into biochemical pathways, a formal procedure is desired to identify the independent pathways in a bioreaction network and the degree of engagement of each individual reaction in these pathways. We present a procedure for the identification of the independent pathways of bioreaction networks of any size and complexity.

Health-related quality of life in survivors of tumours of the central nervous system in childhood--a preference-based approach to measurement in a cross-sectional study.

There is an evident need to measure the comprehensive burden of morbidity experienced by survivors of brain tumours in childhood. To this end, a questionnaire based on the Health Utilities Index mark 2 (HUI2) and mark 3 (HUI3) systems was completed independently for a cohort of such children by their parents, by a nurse, by physicians and by a selected group of the children themselves. Each of the HUI2 and HUI3 systems consists of a multi-attribute health status classification scheme linked to a preference function which provides utility scores for levels within single attributes (domains of health) and for global health states.

Ketosynthase domain probes identify two subclasses of fungal polyketide synthase genes.

Analysis of fungal polyketide synthase gene sequences suggested that these might be divided into two subclasses, designated WA-type and MSAS-type. Two pairs of degenerate PCR primers (LC1 and LC2c, LC3 and LC5c) were designed for the amplification of ketosynthase domain fragments from fungal PKS genes in each of these subclasses. Both primer pairs were shown to amplify one or more PCR products from the genomes of a range of ascomycetous Deuteromycetes and Southern blot analysis confirmed that the products obtained with each pair of primers emanated from distinct genomic loci.

The impact of percutaneous tracheostomy on intensive care unit practice and training.

We studied the impact of introducing percutaneous tracheostomy to our intensive care unit on the incidence and timing of tracheostomy and on the implications for surgical training. The proportion of patients receiving intensive care who underwent tracheostomy doubled from a median of 8.5% to 16.

Experimental determination of group flux control coefficients in metabolic networks.

Grouping of reactions around key metabolite branch points can facilitate the study of metabolic control of complex metabolic networks. This top-down Metabolic Control Analysis is exemplified through the introduction of group (flux, as well as concentration) control coefficients whose magnitudes provide a measure of the relative impact of each reaction group on the overall network flux, as well as on the overall network stability, following enzymatic amplification. In this article, we demonstrate the application of previously developed theory to the determination of group flux control coefficients.

Routine intraoperative laparoscopic cholangiography.

Background: Whether intraoperative laparoscopic cholangiography should be routine is debatable.

Methods: We reviewed the cholangiography experience in 669 consecutive laparoscopic cholecystectomies.

Results: Mean age of the patients was 39 years, 78% were female, and 29% had acute cholecystitis.

Syndrome of inappropriate antidiuretic hormone associated with vinorelbine therapy.

Objective: To describe onset of syndrome of inappropriate antidiuretic hormone (SIADH) associated with vinorelbine therapy for advanced breast cancer.

Case Summary: A 50-year-old white woman with a history of advanced breast cancer refractory to other treatment modalities was receiving vinorelbine. Blood chemistries revealed severely depleted sodium and potassium concentrations from a normal baseline within a 7-day period.

MCAT is not required for in vitro polyketide synthesis in a minimal actinorhodin polyketide synthase from Streptomyces coelicolor.

Background: It has been proposed that Streptomyces malonyl CoA: holo acyl carrier protein transacylases (MCATs) provide a link between fatty acid and polyketide biosynthesis. Two recent studies have provided evidence that the presence of MCAT is essential for polyketide synthesis to proceed in reconstituted minimal polyketide synthases (PKSs). In contrast to this, we previously showed that the holo acyl carrier proteins (ACPs) from type II PKSs are capable of catalytic self-malonylation in the presence of malonyl CoA, which suggests that MCAT might not be necessary for polyketide biosynthesis.

Repeatability and comparability of automated keratometry: the Nikon NRK-8000, the Nidek KM-800 and the Bausch and Lomb keratometer.

This study assessed the repeatability of the Nikon NRK-8000, the Nidek KM-800 and the Bausch and Lomb keratometer. In addition, the comparability of the Nikon NRK-8000 and the Nidek KM-800 are evaluated relative to the Bausch and Lomb keratometer. Measurements were taken with all three techniques on two separate occasions with a test-retest separation of at least 24 hr.

Osteopenia in children surviving brain tumours.

Osteopenia has been reported in children surviving acute lymphoblastic leukaemia, apparently as a consequence of therapy. It has been suggested that cranial irradiation may play a crucial role in this disorder. To explore that possibility, survivors of brain tumours in childhood, all of whom had received radiotherapy, were examined for evidence of bone mineral loss.

Acylation of Streptomyces type II polyketide synthase acyl carrier proteins.

Acyl derivatives of type II PKS ACPs are required for in vitro studies of polyketide biosynthesis. The presence of an exposed cysteine residue prevented specific chemical acylation of the phosphopantetheine thiol of the actinorhodin PKS holo ACP. Acylation studies were further complicated by intramolecular disulphide formation between cysteine 17 and the phosphopantetheine.