The effect of DCIS grade on rate, type and time to recurrence after 15 years of follow-up of screen-detected DCIS.

BACKGROUND: The incidence of ductal carcinoma in situ (DCIS) rose rapidly when the NHS Breast Screening Programme (NHSBSP) started in 1988. Some authorities consider that this represents both over-diagnosis and over-treatment. We report long-term follow-up of DCIS diagnosed in the first 10 years (April 1988 to March 1999) of the West Midlands NHSBSP. METHODS: 840 noninvasive breast cancers were recorded on the national breast screening computer system. Following exclusions, and thorough case note and pathology review, 700 DCIS cases were identified for follow-up. RESULTS: After a median follow-up of 183 (range 133 to 259) months, 102 (14.6%) first local recurrences were identified, 49 (48%) were invasive. Median time to first noninvasive recurrence was 15 months, and 60 months for invasive recurrence. Median time to invasive recurrence was 76 months from initially high-grade DCIS, and 131 months from low/intermediate grade DCIS. For the seven women, presenting with metastasis as their first event, the median time was 82 (range 15 to 188) months. The cumulative proportion developing recurrence at 180 months was twice as high as at 60 months. INTERPRETATION: Short-term follow-up of patients diagnosed with DCIS will miss significant numbers of events, especially invasive local recurrences.

Non-operative diagnosis--effect on repeat-operation rates in the UK breast screening programme.

Non-operative diagnosis rates in the UK breast screening programme have improved dramatically from 48.8% in 1994/95 (only nine units achieved the then minimum standard of 70%) to 94% in 2005/06 (only seven units failed to achieve the target of 90%). Preoperative and operative history of all 120,550 women diagnosed with screen-detected breast cancer in the UK between April 1994 and March 2006 was derived from different national databases. In 2005/06, 2,790 (17.8%) of the 15,688 women having surgery needed two or more operations. In 2001/02 (non-operative diagnosis rate 87%), the re-operation rate was 23.8% (2,377 of 9,969). Extrapolation backwards to 1994/95 (non-operative diagnosis rate 48.8%) suggests a re-operation rate of 62%. Analysis over the 4 years from April 2002 (n=34,198) demonstrates that 4,089 (12%) women with a correct non-operative diagnosis of invasive disease required additional surgery compared to 1,166 (48%) of women who were under-staged (diagnosed as non-invasive based on core biopsy, but actually suffering from invasive disease). Failure to achieve a non-operative diagnosis of invasive disease (n=1,542) or non-invasive disease (n=2,247) resulted in re-operation rates of 65 and 43% respectively. Given the impact of not having a diagnosis pre-operatively, or of under-staging invasive carcinoma, it seems timely to introduce more sophisticated standards.

Slippage in the NHS breast screening programme: an assessment of whether a three year screening round is being achieved.

BACKGROUND: The NHS breast screening programme (NHSBSP) was established in 1987 to screen women aged 50-64 every three years to achieve a significant reduction in breast cancer mortality. Ensuring that women are re-invited every three years (that is, a three year screening round is in operation) is becoming increasingly difficult as pressure on the service rises. Coverage measures the proportion of eligible women receiving a screen in the previous three years and is currently used as an NHS performance indicator, while uptake measures the proportion of invited women who attend for screening. Data for 1996/1997 for the West Midlands NHSBSP show that, although uptake among 50-64 year olds was in excess of the 70% target at 78%, coverage was 10% below this at 68%. The discrepancy between coverage and uptake is likely to in part reflect "round slippage" in which women are re-invited at three years or more from their previous screen. To investigate the extent to which slippage is occurring in the region a technique for assessing round length independently of coverage was developed. METHODS: Records for women receiving routine recall (incident) screens between 1994 and 1997 in the West Midlands NHSBSP were examined and the time between the most recent screen and the previous screen measured in months. FINDINGS: Of 73,785 women screened in 1996/1997, 46.3% had a round length of under three years, although 74.9% had been re-screened within 38 months of the previous screen. Overall the regional programme was estimated to have a round slippage of approximately two months. CONCLUSIONS: The West Midlands NHSBSP operates to high standards in terms of uptake and cancer detection, but round slippage must be reduced. The lack of quantitative data with which to assess round length has hindered assessment in the past. The simple technique developed in this study will allow assessment of round length to be used routinely as the key quality assurance measure for the programme.

Comparison of the imaging characteristics of curved-channel and straight-channel microchannel plates.

We have measured and compared the spatial fidelity of two types of microchannel plates over roughly half of their active area. Measurements of the spatial fidelity of curved-channel microchannel plates confirm earlier reports of large (>25 microm), irregular position offsets between the front and the back of the microchannel plates. Straight-pore microchannel plates used in a chevron configuration, on the other hand, showed almost no such position offsets (<4 microm).

Interval breast cancers in the NHS Breast Screening Programme: does the current definition exclude too many?

OBJECTIVES: To examine the impact of the definition of interval breast cancers on interval cancer rates arising from the prevalent (first) screening round. DESIGN: Interval breast cancers arising from the prevalent (first) screening round at the Warwickshire, Solihull and Coventry Breast Screening Unit (17 April 1989 to 31 March 1992) were identified by comparison of data held at the unit with records at the West Midlands Cancer Intelligence Unit. Exclusion criteria used in National statistics were applied to this sample to quantify their impact on achieved interval cancer rates. The round lengths experienced by individual women at the unit were determined from the prevalent and incident invitation dates for 155 women with incident (re-screen) breast cancers detected in the second round. SETTING: Warwickshire, Solihull and Coventry Breast Screening Unit. SUBJECTS: 59,017 women screened between 17 April 1989 and 31 March 1992 with a negative screening result and 155 women with incident screen detected cancers. RESULTS: A total of 278 interval cancers were identified, giving an overall rate from the prevalent screening round of 47.1/10,000 women screened. Of these, 213 met the criteria used in the definition of interval cancers for National statistics and were termed "core" interval cancers. The overall "core" interval rate was 36.1/ 10,000 women screened, similar to interval cancer rates found in the north west of United Kingdom. Thus applying commonly used exclusion criteria produced a 23.4% reduction in the apparent interval cancer rate, with the largest decrease resulting from the exclusion of cancers arising at 36 months or more from the last screen. CONCLUSIONS: The exclusion criteria used in the definition of interval cancers have a significant impact on observed interval cancer rates. Of particular concern is the exclusion in the current National definitions of cancers arising at 36 months or more from the last screen, which may mask a problem with significant implications for the success of the NHSBSP.

Analysis of the solution structure of human interleukin-4 determined by heteronuclear three-dimensional nuclear magnetic resonance techniques.

Human interleukin-4 (IL-4) is a member of the family of haemopoietic cytokines that modulate cell proliferation and differentiation within the immune system. It has a four-helix-bundle structure, and possesses a high degree of mobility in certain regions, notably in the two long loops running the length of the bundle in its up-up-down-down topology. Information from a variety of three-dimensional heteronuclear NMR experiments, including chemical shifts, coupling constants and NOE data, is analysed in terms of the solution structure of IL-4. In addition, structure calculations with and without specific restraints such as hydrogen bond location or torsion angle restrictions are compared in the light of the dynamic behaviour of the polypeptide chain. Particular emphasis is placed on defining the lengths and positions of secondary structure elements, and on the likely structural preferences within the less well ordered loop regions. The overall topology of IL-4 is compared with those defined in recent structure determinations of related proteins. This analysis is combined with recent mutagenesis data to propose a possible mode of interaction of IL-4 with its receptor.

Human interleukin 4. The solution structure of a four-helix bundle protein.

Heteronuclear 13C and 15N three-dimensional nuclear magnetic resonance (n.m.r.) techniques have been used to determine the solution structure of human interleukin 4, a four-helix bundle protein. A dynamical simulated annealing protocol was used to calculate an ensemble of structures from an n.m.r. data set of 1735 distance restraints, 101 phi angle restraints and 27 pairs of hydrogen bond restraints. The protein structure has a left-handed up-up-down-down topology for the four helices with the two long overhand loops in the structure being connected by a short section of irregular antiparallel beta-sheet. Analysis of the side-chains in the protein shows a clustering of hydrophobic residues, particularly leucines, in the core of the bundle with the side-chains of charged residues being located on the protein surface. The solution structure has been compared with a recent structure prediction for human interleukin 4 and with crystal structures of other helix bundle proteins.

Epithelial expression of major histocompatibility complex (MHC) antigens in normal rat salivary and lacrimal glands.

The presence and distribution of MHC class I and class II antigens within these glands of Wistar and Lewis rats was studied using monoclonal antibodies and an indirect immunoperoxidase technique. In rats of both strains and sexes, MHC class 1 antigens were expressed by ductal epithelium in addition to vascular endothelium and other connective tissue elements. Except for a small proportion of secretory cells within lacrimal glands, acini were uniformly negative for class I antigen. MHC class II immune response-associated (Ia) antigens were expressed by stromal dendritic cells in all glands. Glandular expression of Ia was limited to submandibular glands of the two strains. In Lewis rats, staining was detected in some striated and collecting ducts, whereas positive glandular reactivity in Wistar rats was predominantly within the granular-cell tubules. Quantitative histomorphometric studies of Wistar submandibular glands, taken from 2.5-60-week-old male and female animals, demonstrated a close relationship between the extent of glandular Ia reactivity and postnatal granular-cell tubule development. These results indicate that whilst constitutive expression of Ia is a feature of rat submandibular epithelium, the glandular components involved are strain dependent.

Secondary structure and topology of human interleukin 4 in solution.

Human interleukin 4 (IL-4) has been studied by 2D and 3D NMR techniques using uniformly 15N-labeled recombinant protein. Assignment of resonances for all but 3 of the 130 residues of the recombinant protein has been achieved, enabling the secondary structure of the protein to be defined. This consists of four major alpha-helical regions and one short section of double-stranded antiparallel beta-sheet. Analysis of distance and angle restraints derived from NMR experiments has enabled the overall molecular topology to be determined. This is related to that found for other four-helix proteins but has several distinctive features including cross-linking of helices by means of three disulfide bonds and a short section of beta-sheet. The structural analysis gives support to the hypothesis that many helical cytokines have a common fold and provides a basis for understanding the biological function of IL-4.

An orthodontic evaluation of 16-year-old males with an original complete unilateral cleft lip and palate problem repaired during the neonatal period.

A cephalometric analysis is presented of a group of 21 16-year-old males born with complete unilateral clefts of lip and palate with surgical repair carried out in the neonatal period. Comparisons are made with the multicentre study reported by Ross (1987). The study demonstrates that the effect of early surgery on facial growth is similar to that of the average of the multicentre study.

Position offsets in curved-channel microchannel plate detectors.

Microchannel plate detectors are widely used for ultraviolet (UV) and extreme-ultraviolet (EUV) observations. Curved-channel microchannel plates, or C plates, provide an electron gain of approximately 10(6) in a single plate because the curved channels prevent ion feedback. However, offsets between input and output in curved-channel microchannel plates produce slight distortions in the spatial or spectral scale of thedetector, complicating the use of such detectors for high-resolution imaging and spectroscopy. We have examined the image distortion caused by nonconstant curvature of the channels by (a) observing spectral nonlinearities in an EUV spectrometer, (b) measuring the positions of several plugged channels of a typical plate and comparing the positions of the channels on both the input and the output sides, and (c) mapping input versus output of typical plates, using a mechanically scanned spot of UV light. We find that a typical C plate with 25-microm-diameter pores exhibits +/-25-microm image distortion across the plate. Calibration of this image distortion as reflected in the spectral nonlinearity of our EUV spectrograph improves the spectral line positions by a factor of 4, permitting solar-emission-line Doppler shift determination of +/- 2 microm (+/- 1 km/s).

Thioacetamide-induced changes in hepatic hexokinase isoenzymes.

In the 48 h following a single i.p. injection of 200 mg of thioacetamide/kg body wt there is a progressive rise in low-Km hexokinase activity and a concomitant decrease in high-Km glucokinase activity. Loss of glucokinase activity occurs as a consequence of its predominantly perivenous zonal distribution in normal liver since it is hepatocytes in this region of the acinus that are selectively damaged by thioacetamide. Increased low-Km activity is mainly present in inflammatory infiltrates which invade perivenous and mid-zone regions in response to tissue injury. Low- and high-Km hexokinase activities return to control levels 10 days after thioacetamide treatment when the infiltration zones disappear and necrotic perivenous hepatocytes are replaced by cells with normal morphology. Changes in low- and high-Km hexokinase activities induced by thioacetamide thus appear to primarily reflect alterations in cell population rather than changes in gene expression within existing hepatocytes.

The use of continuous monitoring and computer-assisted image analysis for the histochemical quantification of hexokinase activity.

The effect of endogenous 6-phosphogluconate dehydrogenase (6PGDH) on the histochemical quantification of low-Km hexokinase activity in rat submandibular salivary glands has been investigated using a Seescan Solitaire Plus image analysis system and a modified black and white Newvicon TV camera. Absorbance readings of neutral density filters were close to their known absorbance values. A significant correlation was found between the absorbance of Nitro BT reduction products within sections, with and without the use of a 588 nm interference filter. Furthermore, absorbance readings obtained from 8 microns-thick sections were 1.92 and 2.22 times greater than values obtained from 4 microns-thick sections using 'white' and 588 nm light respectively. The level of background illumination was not critical for absorbance measurements provided it was below the level that saturated the Newvicon camera and was not changed between background and image capture. The greatest variations in absorbance readings on tissue sections were associated with changes in zoom and objective combinations. Our studies indicate that this relatively low cost image analysis system can give reproducible absorbance readings from various structures defined in digitized, captured images of tissue sections. Results from continuous monitoring studies indicated that the high levels of 6PGDH activity in excretory ducts caused a 1.67-fold overestimation of hexokinase activity as assessed by absorbance readings performed throughout a 22-minute reaction period. By contrast, overestimation of hexokinase activity in salivary gland acini only became apparent after 8 min incubation with a 1.4-fold overestimation being seen at 22 min. This difference appears to reflect the relatively low hexokinase and 6PGDH activities present in acini compared with excretory ducts.

Hex-square moire patterns in imagers using microchannel plates.

In electronic imaging detectors using microchannel plates, the mismatch between the pixels on a square mesh and the microchannels on a hexagonal mesh produces moire image defects. Theoretical statistical estimates of the sizes of the microposition offsets and the flat field intensity errors are calculated, showing the trade-off between resolution and position accuracy. A distinction is made between moments of spot images and moments of the single pixel response functions. As the resolution between the hex and square meshes is improved, the detector resolution is improved but at the expense of an ~10% moire pattern. These moire patterns will not be properly corrected by dividing by the flat field image.

A tissue-type plasminogen activator mutant with prolonged clearance in vivo. Effect of removal of the growth factor domain.

The complete cDNA for human tissue-type plasminogen activator (t-PA) was cloned and sequenced. A mutant was constructed by using in vitro site-specific mutagenesis to delete the region encoding the growth factor domain (amino acids 51-87 inclusive). Normal and mutant t-PA species were produced using two mammalian expression systems (in human HeLa cells and mouse C127 cells). The clearance of mutant and normal t-PA from plasma was examined in vivo using a guinea pig model. Mutant t-PA derived from HeLa or C127 cells was cleared much more slowly than the cognate normal t-PA. The potential role of the growth factor domain in the recognition of t-PA by the hepatic clearance mechanism is discussed.

The effect of diurnal rhythms on the hepatotoxicity of thioacetamide in male and female rats.

Single 200 mg/Kg body weight i.p. injections of thioacetamide administered to litter mate male and female rats at 09.00, 13.00, 17.00 and 21.00 h caused body weight losses, elevated plasma glutamate pyruvate transaminase (GPT) levels, decreases in hepatic glycogen, zone 3-specific necrosis and leucocyte infiltration. All of these changes were more marked in males. The effects of thioacetamide on females were more severe at later injection times while no diurnal variations were apparent in males. Decreases in hepatic glycogen were most obvious in necrotic perivenous hepatocytes and correlated with increases in active glycogen phosphorylase which were probably caused by raised cytosolic calcium concentrations resulting from thioacetamide induced damage to cell membranes.

Histochemical evidence of changes in fuel metabolism induced in red, white and intermediate muscle fibres of streptozotocin-treated rats.

The present study provides histochemical evidence supporting the operation of the 'glucose-fatty acid cycle' in skeletal muscles taken 5 days after the administration of a single injection of streptozotocin. It also indicates that the cycle is more important in fast-oxidative-glycolytic (FOG) and slow-oxidative (SO) fibres than in fast-glycolytic (FG) fibres. Data from muscles taken 14 and 28 days after treatment suggest that lipid catabolism becomes progressively less important with time, and that muscles from longer-term diabetic rats rely on the aerobic and anaerobic breakdown of glucose by FOG and FG fibres to meet their cellular energy requirements. Although SO fibres appeared initially to be the least affected by streptozotocin-induced diabetes, the decline in their metabolic capabilities ultimately seemed to be greater than that in FOG fibres. Transformations in the biochemical characteristics of FOG and SO fibres occurred 14-28 days after streptozotocin treatment, in the absence of changes in actomyosin-ATPase activity. This supports the view that the division of skeletal muscle fibres into three or four distinct types on the basis of myosin- or actomyosin-ATPase activity is an oversimplification of the true situation.

The compartmentation of glycolytic and gluconeogenic enzymes in rat kidney and liver and its significance to renal and hepatic metabolism.

An indirect immunoperoxidase procedure has been used to demonstrate sites of glycolysis and gluconeogenesis in normal rat kidney and liver. In kidney, the gluconeogenic enzyme fructose 1,6-biphosphatase was restricted to the proximal tubular epithelium, while the glycolytic enzyme hexokinase predominated in more distal segments. Intense staining for the biphosphatase in proximal convoluted tubular brush borders suggests that reabsorbed substrates may be used directly at this site in renal gluconeogenesis. In view of the high phosphofructokinase and pyruvate kinase activities present in collecting ducts, their relatively low hexokinase activities and their relatively pale immunostaining for hexokinase indicate that glycolytic substrates which feed into the pathway subsequent to the initial phosphorylation step, rather than glucose, may be the major energy source for the rat renal papilla. Immunostaining in the liver was consistent with the metabolic zonation of liver parenchyma, in that glucokinase occurred mainly in perivenous regions and fructose 1,6-bisphosphatase in periportal areas. The presence of such metabolic zonation is difficult to reconcile with the widely held view that the majority of hepatic glycogen is derived directly from glucose. A model for hepatic glycogen synthesis is proposed which links the concept of parenchymal zonal heterogeneity with recent biochemical evidence concerning the 'glucose paradox' and with microscopical studies on the dynamics of glycogen deposition after refeeding.