A multicentre study of the precision and accuracy of the TruSlice and TruSlice Digital histological dissection devices.

BACKGROUND: Five key factors enabling a good surgical grossing technique include a flat uniformly perpendicular specimen cutting face, appropriate immobilisation of the tissue specimen during grossing, good visualisation of the cutting tissue face, sharp cutting knives and the grossing knife action. TruSlice and TruSlice Digital are new innovative tools based on a guillotine configuration. The TruSlice has plastic inserts whilst the TruSlice Digital has an electronic micrometre attached: both features enable these dissection factors to be controlled. The devices were assessed in five hospitals in the UK. MATERIAL AND METHODS: A total of 267 fixed tissue samples from 23 tissue types were analysed, principally the breast (n = 32) skin (30), rectum (28), colon (27) and cervix (17). Precision and accuracy were evaluated by measuring the defined thickness, and the consistency of achieving the defined thickness of tissue samples taken respectively. Both parameters were expressed as a total percentage of compliance for the cohort of samples accessed. RESULTS: Overall, the mean (standard deviation) score for precision was 81 (11) % whilst the accuracy score was 82 (11) % (both p < 0.05, chi-squared test), although this varied with type of tissue. Accuracy and precision were strongly correlated (rp = 0.83, p < 0.001). CONCLUSION: The TruSlice Digital devices offer an assured precision and accuracy performance which is reproducible across an assortment of tissue types. The use of a micrometre to set tissue slice thickness is innovative and should comply with laboratory accreditation requirements, alleviating concerns of how to tackle issues such as the 'measurement of uncertainty' at the grossing bench.

Structure of the RNA-dependent RNA polymerase of poliovirus.

BACKGROUND: The central player in the replication of RNA viruses is the viral RNA-dependent RNA polymerase. The 53 kDa poliovirus polymerase, together with other viral and possibly host proteins, carries out viral RNA replication in the host cell cytoplasm. RNA-dependent RNA polymerases comprise a distinct category of polymerases that have limited sequence similarity to reverse transcriptases (RNA-dependent DNA polymerases) and perhaps also to DNA-dependent polymerases. Previously reported structures of RNA-dependent DNA polymerases, DNA-dependent DNA polymerases and a DNA-dependent RNA polymerase show that structural and evolutionary relationships exist between the different polymerase categories. RESULTS: We have determined the structure of the RNA-dependent RNA polymerase of poliovirus at 2.6 A resolution by X-ray crystallography. It has the same overall shape as other polymerases, commonly described by analogy to a right hand. The structures of the 'fingers' and 'thumb' subdomains of poliovirus polymerase differ from those of other polymerases, but the palm subdomain contains a core structure very similar to that of other polymerases. This conserved core structure is composed of four of the amino acid sequence motifs described for RNA-dependent polymerases. Structure-based alignments of these motifs has enabled us to modify and extend previous sequence and structural alignments so as to relate sequence conservation to function. Extensive regions of polymerase-polymerase interactions observed in the crystals suggest an unusual higher order structure that we believe is important for polymerase function. CONCLUSIONS: As a first example of a structure of an RNA-dependent RNA polymerase, the poliovirus polymerase structure provides for a better understanding of polymerase structure, function and evolution. In addition, it has yielded insights into an unusual higher order structure that may be critical for poliovirus polymerase function.

Isolation and characterization of a virus infecting the freshwater algae Chrysochromulina parva.

Water samples from Lake Ontario, Canada were tested for lytic activity against the freshwater haptophyte algae Chrysochromulina parva. A filterable lytic agent was isolated and identified as a virus via transmission electron microscopy and molecular methods. The virus, CpV-BQ1, is icosahedral, ca. 145nm in diameter, assembled within the cytoplasm, and has a genome size of ca. 485kb. Sequences obtained through PCR-amplification of DNA polymerase (polB) genes clustered among sequences from the family Phycodnaviridae, whereas major capsid protein (MCP) sequences clustered among sequences from either the Phycodnaviridae or Mimiviridae. Based on quantitative molecular assays, C. parva׳s abundance in Lake Ontario was relatively stable, yet CpV-BQ1׳s abundance was variable suggesting complex virus-host dynamics. This study demonstrates that CpV-BQ1 is a member of the proposed order Megavirales with characteristics of both phycodnaviruses and mimiviruses indicating that, in addition to its complex ecological dynamics, it also has a complex evolutionary history.

National health expenditures, 1995.

This article presents data on health care spending for the United States, covering expenditures for various types of medical services and products and their sources of funding from 1960 to 1995. In 1995, $988.5 billion was spent to purchase health care in the United States, up 5.5 percent from 1994. Growth in spending between 1993 and 1995 was the slowest in more than three decades, primarily because of slow growth in private health insurance and out-of-pocket spending. As a result, the share of health spending funded by private sources fell, reflecting the influence of increased enrollment in managed care plans.

National health expenditures, 1997.

In 1997 health spending in the United States increased just 4.8 percent to $1.1 trillion. As a share of gross domestic product (GDP), national health expenditures (NHE) absorbed 13.5 percent of the country's output in 1997--a share that has remained relatively constant for 5 years. Despite the relative stability in recent years, signs of changing trends are emerging.

National health expenditures, 1999.

The health care spending share of gross domestic product (GDP) remained steady between 1993 and 1999 as moderate-to-strong economic growth coincided with a rapid shift to managed care. This shift, along with decelerating growth in Medicare spending, appears to have generated a mostly one-time saving that lowered aggregate health expenditure growth.

National health expenditures, 1994.

This article presents data on health care spending for the United States, covering expenditures for various types of medical services and products and their sources of funding from 1960 to 1994. Although these statistics for 1994 show the slowest growth in more than three decades, health spending continued to grow faster than the overall economy. The Federal Government continued to fund an increasing share of health care expenditures in 1994, offset by a falling share from out-of-pocket sources. Shares paid by State and local governments and by other private payers including private health insurance remained unchanged from 1993.

National health expenditures, 1996.

The national health expenditures (NHE) series presented in this report for 1960-96 provides a view of the economic history of health care in the United States through spending for health care services and the sources financing that care. In 1996 NHE topped $1 trillion. At the same time, spending grew at the slowest rate, 4.4 percent, ever recorded in the current series. For the first time, this article presents estimates of Medicare managed care payments by type of service, as well as nursing home and home health spending in hospital-based facilities.

National health expenditures, 1998.

In 1998, national health care expenditures reached $1.1 trillion, an increase of 5.6 percent from the previous year. This marked the fifth consecutive year of spending growth under 6 percent. Underlying the stability of the overall growth, major changes began taking place within the Nation's health care system. Public payers felt the initial effects of the Balanced Budget Act of 1997 (BBA), and private payers experienced increased health care costs and increased premium growth.

Indwelling cannula for insulin administration in diabetes mellitus.

Experience with an indwelling subcutaneous Teflon cannula for insulin delivery to 10 children with diabetes mellitus is described. There were no significant complications during a one year trial period. The device may particularly benefit children during the early phase after diagnosis and for those with true needle phobia.

The effect of companion on consumption of ethanol solution in cats.

Social influences on drinking ethanol solution were studied in two cats ("drinkers") who voluntarily drank small amounts of 10% ethanol solution in milk and three other cats ("nondrinkers") who served as companions to the drinkers. A 15-minute session was conducted daily in a compartment divided into two even parts with a transparent Plexiglass partition. The cats were introduced to the compartment either singly or in pairs. Each pair consisted either of two drinkers or one drinker and one nondrinker. Each cat of the pair was placed in one part of the compartment; the cats could see each other, but they could not make physical contact. Each drinker was offered 10% ethanol solution in milk, while each nondrinker was given plain milk, and the amount of consumption was measured. A series of five to ten sessions with a drinker was followed by a series of sessions with a nondrinker or with no companion. There were a total of 13 series of sessions for each drinker. A statistical analysis of the data showed that, in most series, the mean amount of consumption of ethanol solution was significantly higher in the presence of a companion (either drinker or nondrinker) than in its absence.

Iodine in the soils of North Derbyshire.

Derbyshire was one of the best known centres of endemic goitre in Great Britain. Some 160 km from the coast in the direction of the prevailing wind, topsoils in the area are generally low in iodine (mean = 5.44 mg l/kg). Weathered rocks and soils are richer in iodine than the unweathered bedrocks, with soils developed over limestones being richer than those over sandstones, shales and dolomites. Highest iodine contents in soil profiles over limestones occur in the upper horizons while over sandstones, iodine concentrates in the lower horizons. The major cause of endemic goitre in north Derbyshire is likely to be relatively low levels of iodine, while the calcium rich soils of the area may contribute by reducing plant iodine uptake.

Fetal hydrometrocolpos.

This report describes a case of hydrometrocolpos presenting antenatally as a cystic mass arising from the pelvis of a female fetus. The baby was born at 33 weeks and died within an hour due to pulmonary hypoplasia. Postmortem examination demonstrated hydrometrocolpos, dense adhesions in the abdomen and pulmonary hypoplasia.

Hopf bifurcations and the stability of the respiratory control system.

A simple model of a feedback loop controlling ventilation is analysed. This model is intended to describe the response of the system, initially at equilibrium, to a sudden fall in CO2 concentration in the lung, brought about by a deep sigh. A previous paper described the model in detail and the general method of analysis. Here we continue the discussion of stability, first in terms of local stability after a small displacement from equilibrium and then by computer simulation to illustrate the behaviour after large displacements. The local analysis is used to select representative sets of system parameters to illustrate the different types of trajectory obtained by computer simulation. When the equilibrium point is stable the response to a disturbance is overdamped, underdamped or critically damped. When the equilibrium point is unstable the system responds by going into a limit cycle. The transition between these two cases proceeds via a Hopf Bifurcation. The limit cycle type of ventilatory pattern, i.e. a periodic, underdamped waxing and waning of ventilation is commonly seen in premature infants and in term infants between 1 and 6 months of age.

Crystal structure of a bacteriophage T7 DNA replication complex at 2.2 A resolution.

DNA polymerases change their specificity for nucleotide substrates with each catalytic cycle, while achieving error frequencies in the range of 10(-5) to 10(-6). Here we present a 2.2 A crystal structure of the replicative DNA polymerase from bacteriophage T7 complexed with a primer-template and a nucleoside triphosphate in the polymerase active site. The structure illustrates how nucleotides are selected in a template-directed manner, and provides a structural basis for a metal-assisted mechanism of phosphoryl transfer by a large group of related polymerases.

Prevention of spread of echovirus 6 in a special care baby unit.

A case of fatal neonatal infection with enteric cytopathogenic human orphan virus (echovirus) type 6 is presented. The measures taken to prevent further spread of infection with special reference to the use of human normal immunoglobulin are described.