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.

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.

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.

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).

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).

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.

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.

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.

Comparison of glucokinase in C3H/He and C58 mice that differ in their hepatic activity

Partially purified preparations of the hepatic glucokinase from C3H/He and C58 inbred mice have been used to explore the molecular basis for the observed twofold difference in activity between the strains. The single codominant gene that appears to regulate activity, the alleles of which are designated Gka and Gkb, respectively, for the two strains, could represent a structural gene change. This now seems unlikely because the mouse enzyme, although showing small differences from rat glucokinase, appeared to be identical in the two strains with respect to thermal stability, electrophoretic mobility in agarose gels, and kinetic properties such as the apparent Km values for MgATP2- and glucose and the unique cooperative interaction with the latter substrate. The enzymes also reacted identically in a range of immunological tests (double-diffusion, immunoelectrophoresis, immune precipitation and immune inhibition assays) and ELISA immune inhibition assays indicated that the twofold difference in activity was due to a similar difference in antigenically active enzyme. Genetic control over the physiologically significant regulation of enzyme amount is therefore probable.

The localization of hexokinase isoenzymes in red and white skeletal muscles of the rat

Maximum assayable hexokinase activities vary with the proportion of red, fast-twitch, oxidative-glycolytic and intermediate, slow-twitch, oxidative fibres in different rat skeletal muscles. The major isoenzymic form, type II hexokinase, is present throughout the intermyofibrillar sarcoplasm in all fibres but a proportion of the total activity appears to be weakly associated with mitochondria. Variations in the histochemical staining intensity between fibre types correlate with their mitochondrial content and seem to be due mainly to differences in mitochondrially-associated hexokinase activity. Changes in the strength of this association may be important in controlling increases in glucose metabolism in response to prolonged increased muscular activity while regulation of the equilibrium between free and loosely-bound forms may be an important control feature in all skeletal muscle. Type I hexokinase is a minor isoenzymic component of skeletal muscle and occurs mainly in blood vessels and nerves in the perimysia and endomysia. The majority of this isoenzyme is tightly bound to mitochondria and is not detectable in homogenates prepared in the absence of Triton X-100.

Histochemical and immunohistochemical localization of hexokinase isoenzymes in normal rat liver

Histochemical and immunohistochemical procedures have been used to examine the localization of three of the four hexokinase isoenzymes present in the liver of fed female Wistar rats. Distinctive distribution patterns were found for hexokinase type I and glucokinase but hexokinase type II was not detectable. Hexokinase type I was identified in sinusoidal cells and in bile duct epithelia, nerves and arteries in the portal triad. Glucokinase, the major isoenzyme, was confined to parenchymal cells where it was present in much higher amounts in perivenous compared with periportal hepatocytes. Staining within these two zones was not homogeneous and each had a mosaic appearance caused by the presence of a few hepatocytes containing little or no glucokinase amongst the majority of darkly stained cells in perivenous areas and a few darkly stained cells amongst the majority of unstained cells in periportal areas. Hence, hepatocytes in situ are a strikingly heterogeneous population of cells. Their metabolic status cannot be controlled simply by the differential supply of oxygen, substrates and hormones to different regions of the liver acini as proposed in the metabolic zonation model. Phenotypic differences may exist between cells within a given metabolic zone which influence their ability to respond to different environmental conditions.

The ubiquitous localization of type I hexokinase in rat peripheral nerves, smooth muscle cells and epithelial cells

An indirect immunoperoxidase technique has been used to determine the localization of type I hexokinase in a wide variety of Carnoy-fixed, paraffin-embedded rat tissues. The results suggest that the widespread tissue distribution of the isoenzyme is due to its ubiquitous localization in the nervous, smooth muscle and epithelial components of each tissue. The majority of the immunostaining was confined to cells with substantial energy requirements which are probably mainly satisfied through the breakdown of glucose. This observation is consistent with the known predominance of type I hexokinase in the central nervous system and with the regulatory role allotted to it in this tissue.

Histochemical and immunohistochemical localization of hexokinase isoenzymes in rat kidney

Histochemical and immunohistochemical staining techniques have been used to investigate the localization of hexokinase isoenzymes within rat kidney tissue. Hexokinase type I was shown to be the major isoenzyme present. It was located mainly in the thin and thick limbs of loops of Henle, in distal tubules and in the transitional or dark cells in the initial portions of collecting ducts. The smooth muscle cells of arteries and arterioles, peripheral nerves and the transitional epithelial cells lining the renal pyramid also contained large amounts of the isoenzyme while smaller quantities were present in glomeruli and in collecting tubules near the papillary tip. The distribution pattern obtained in tubular epithelia agrees well with that demonstrated in earlier microdissection studies. It is also consistent with the suggestion that glycolysis provides the majority of the energy fuelling the sodium transport mechanisms which form such an essential feature of the countercurrent urine concentration system present within the renal medulla.

Effect of molecular charge on the induction of proteinuria and glomerular ultrastructural damage in hyperalbuminaemic female Wistar rats

Intraperitoneal injection of anionic carbamylated bovine albumin derivatives induced glomerular epithelial cell foot process loss and increased urinary protein excretion, the severity of which rose with the dose administered. The effects induced at a given albumin dose were significantly lower than those previously measured after the administration of normal bovine albumin. The amount of epithelial cell foot process loss induced after the injection of carbamylated bovine albumin derivatives correlated well with the level of induced proteinuria but, at a given level of proteinuria, the amount of foot process was lower in these rats compared with those given normal bovine albumin. The results obtained are consistent with the interpretation that the more anionic carbamylated bovine albumin derivatives were not only filtered less readily at the glomerulus than their less negatively charged counterparts but were also reabsorbed to a lesser extent by the tubular epithelium.

Glomerular ultrafiltration and tubular reabsorption of bovine serum albumin and derivatives with increased negative charge in the normal female Wistar rat

Urinary clearances of bovine albumin derivatives rose with their increasing negative charge. A mathematical model has been developed to assess the relative contributions of glomerular ultrafiltration and tubular reabsorption to overall urinary protein clearance. This model indicates that the increased urinary clearance seen with negatively charged bovine albumin derivatives was due to a large reduction in the amount of protein absorbed by the proximal tubular epithelium, which swamped the effects of a small decrease in glomerular ultrafiltration. Derivatives of bovine albumin with increasing negative charge were also cleared with correspondingly greater rapidity from the blood stream.

Hexokinase isoenzymes: antigenic cross-reactivities and amino acid compositional relatedness

Previously undetected antigenic cross-reactivities have been demonstrated between yeast and rat hexokinase isoenzymes using an enzyme-linked immune sorbent assay. The levels of structural homology between the isoenzymes have been assessed in terms of their relative antigenic cross-reactivities and their amino acid compositional relatedness. The three major rat hexokinases appear, despite their differing molecular sizes, to have a close evolutionary background and to share a common but distant ancestry with yeast and wheat-germ forms.

Antigenic cross-reactivities between mammalian hexokinases

Immunoelectrophoresis and gel diffusion techniques have demonstrated that, contrary to previous reports, antigenic cross-reactivity does exist between the three major rat hexokinase isoenzymes. Immune inhibition and immune precipitation assays performed in parallel generally failed to detect this cross-reactivity and possible reasons for this failure are discussed. The inability of the latter assay systems to detect cross-reactivity would seem to account for the discrepancies between the present results and those obtained in earlier studies.

A morphometric, biochemical and histochemical comparison of puromycin aminonucleoside and hyperalbuminaemic induced proteinurias in the female Wistar rat

Biochemical, immunological, histochemical and electron microscope morphometric techniques were used to monitor the changes in urinary protein composition, albumin clearance and glomerular ultrastructure induced in female Wistar rats following i.p. injection of puromycin aminonucleoside (PAN) or bovine albumin (BSA). BSA injected rats maintained a high degree of selectivity with albumin constituting 90 per cent. of the total protein excreted even when mean protein excretion was in the order of 500 mg/24 hr. A similar degree of selectivity was only evident in PAN nephrotic rats at low levels of proteinuria. Levels of 500 mg/24 hr only 57 per cent. of the total protein was albumin. These differences correlated well with the increased number of glomeruli from PAN nephrotics compared with hyperalbuminaemic rats which, at these high levels of proteinuria, had bare areas of glomerular basement membrane caused by epithelial cell detachment (88 and 7 per cent. respectively). Detailed electron microscope morphometric and immunohistochemical studies showed that there were also important quantitative differences in a number of superficially similar glomerular structural alterations. In PAN nephrotic rats all glomeruli showed very marked epithelial cell foot process loss and reduced staining with colloidal iron. In glomeruli from hyperalbuminaemic rats there was a wide variation in the extent of epithelial cell foot process loss and reduced colloidal iron staining was only demonstrable in those glomeruli which had swollen epithelial containing large numbers of vacuoles and protein droplets. Similarly, while protein droplets were smaller and less numerous in glomeruli from PAN-injected rats, they were present in most glomeruli whereas their distribution was much more variable in glomeruli from BSA-injected rats. All the data collected therefore indicated that there were important differences in the types of proteinuria and glomerular ultrastructural damage present in PAN nephrotic and hyperalbuminaemic rats and suggested that their induction may have involved entirely different mechanisms. Evidence gathered from one experimental model should thus only be used with extreme caution to aid in interpretation of data obtained from the other.

Studies on the relationship between proteinuria and glomerular ultrastructural change in hyperalbuminaemic female Wistar rats

Increased albumin filtration was shown to cause glomerular epithelial cell foot process loss in female Wistar rats made hyperalbuminaemic by means of a series of intraperitoneal bovine albumin injections. It appeared to act by stimulating glomerular epithelial cell endocytosis with the result that protein droplets and vacuoles accumulated within the epithelium causing marked cytoplasmic swelling which forced the foot processes to spread out and fuse. The severity of this glomerular ultrastructural damage rose with increasing bovine albumin dose and correlated well with induced proteinuria.

Rocket-borne instrument with a high-resolution microchannel plate detector for planetary UV spectroscopy

A telescope-spectrograph employing a photon-counting microchannel plate (MCP)-CODACON detector has been built, tested, and flown on a sounding rocket. The detector uses a curved-channel MCP proximity focused onto a coded anode array of 1024 channels spaced 25.4-mm center to center. High quantum efficiency is obtained by depositing a cesium iodide photocathode on the front surface of the MCP. The instrument has obtained an ultraviolet (1500-1800-A) spectrum of Jupiter with a spectral resolution of 8 A, which is higher than that of any previously reported observation in this wavelength range.

A biochemical and immunological investigation into the physiological basis of the increased albumin filtration induced in hyperalbuminaemic female Wistar rats

1. The level of proteinuria induced in female Wistar rats after bovine albumin injection intraperitoneally was highly dose dependent. 2. The proteinuria remained highly selective, with albumin constituting approximately 90% of the total protein excreted, even in the most severely affected rats. 3. Calculations relating the amount of bovine albumin available in the serum for filtration to the amount excreted in the urine indicated that complete saturation of the reticuloendothelial and tubular protein reabsorption systems may have occurred during the course of the 5 day injection period in rats given more than 3.5 mg of bovine albumin day-1 g-1 body wt. 4. When this situation was attained there appeared to be no further increase in glomerular permeability to either rat or bovine albumin and an equilibrium state seemed to exist where, when serum albumin levels were raised above the normal level, all the excess albumin passed across the glomerular filter to be excreted in the urine. 5. The passage of these large quantities of albumin across the glomerular filter may have resulted not from ultrastructural damage to the filter itself but rather from the generation of vastly increased concentration gradients across the glomerular basement membrane, which were sufficiently large to overcome the electrostatic repulsive forces which normally severely restrict albumin filtration.

Effect of strain and sex on the induction of hyperalbuminaemic proteinuria in the rat

1. Male and female rats representing the four inbred strains [Wistar (albino), Sprague-Dawley (albino), DA (brown) and PVG (hooded) rats] were injected intraperitoneally with 4 . 5-5 . 5 mg of Cohn V bovine albumin day-1 g-1 body wt. 2. The levels of proteinuria and glomerular ultrastructural damage induced in response to hyperalbuminaemia varied widely with the strain and sex of rat studied, being highest in the male Wistar and lowest in the male Sprague-Dawley. 3. A survey of the relevant literature shows that these results probably explain most of the reported inconsistencies and anomalies concerning the effect of parenteral protein injection in the rat.

Normal urinary protein composition in the female Wistar rat and its relationship to the proteinuria induced by intraperitoneal bovine albumin

1. Normal female Wistar rats showed a wide range of baseline protein excretion and albuminuria and could be divided into two distinct groups: (a) low-to-intermediate excretors, where daily baseline albumin excretion was below 1.8 mg/24 h and (b) high excretors, where daily baseline albumin excretion was 1.8-22 mg/24 h. 2. In low-to-intermediate excretors "sex-associated' by urinary specific proteins, supposedly present only in male rat urine, were excreted in larger quantities than albumin which constituted only 10-15% of the total urinary protein. 3. In high excretors up to 50% of the urinary protein was albumin and other serum proteins were also present in relatively larger quantities than the urinary specific proteins. 4. Baseline albumin excretion appeared to be a good indicator of the inherent efficiency of the glomerular filter and this was reflected in the response to intraperitoneal injection of heterologous serum albumin since, during periods where no significant glomerular epithelial cell foot-process loss had been incurred, the levels of proteinuria induced correlated well with baseline albuminuria.

Abortion experiences among New Zealand women

In May 1976 the incidence of abortion among New Zealand women was surveyed over a national random probability sample of 1200 women aged 15 years and over. Of the respondents who had ever been pregnant, 16.6 percent had at some stage considered terminating their pregnancy, and one-third of them subsequently attempted to obtain an abortion with 84 percent success. Single women and/or women in the 15-24 year age group were more likely than married or older women to have considered abortion when pregnant, and were more likely to have followed through with an abortion attempt after considering abortion. Prior to 1974, 62 percent of the abortion attempts involved an unqualified operator, in contrast to only 5 percent of those attempted or obtained from 1974-1976. Women with abortion experiences shifted from a low incidence of contraception and reliance on inadequate methods prior to the abortion attempt, to a higher incidence and use of more adequate methods subsequent to the abortion attempt. Extrapolation from the survey data yielded a median estimated incidence of 8000 abortions per annum on New Zealand women.

Contraceptive practice among New Zealand women

In May 1976 the contraceptive practices of New Zealand women were surveyed among a national random probability sample of 1200 women aged 15 years and over. The survey found 93 percent of women aged 15-44 years considered themselves at risk of pregnancy. Of all women surveyed, almost half (two-thirds of those at risk) currently practised contraception. The highest incidence was among women aged 25-44 years. Single women at risk contracepted less frequently than did married women. The most frequently used method was the contraceptive pill, favoured particularly by younger women. It was followed by sterilisation of either partner, which was most frequent among women aged 25-44 years.

Excitation of the Venus Night Airglow

The strongest spectral features in the Venus night airglow between 3000 and 8000 angstroms are identified as the Herzberg. II (c(1)Sigma(-)(u) - X(3)Sigma(-)(a)) bands of molecular oxygen. These bands have been produced in a laboratory afterglow by the recombination of oxygen atoms in the presence of carbon dioxide molecules. It is hypothesized that the same mechanism produces this emission in the upper atmosphere of Venus.

Determination of the line shapes of atomic nitrogen resonance lines by magnetic scans

A technique is given for calibrating an atomic nitrogen resonance lamp for use in determining column densities of atoms in specific states. A discharge lamp emitting the NI multiplets at 1200 A and 1493 A is studied by obtaining absorption by atoms in a magnetic field (0-2.5 T). This magnetic scanning technique enables the determination of the absorbing atom column density, and an empirical curve of growth is obtained because the atomic f-value is known. Thus, the calibrated lamp can be used in the determination of atomic column densities.