Depression and anxiety after total joint replacement among older adults: a meta-analysis

OBJECTIVE

Patients usually experience good physical recovery after total joint replacement (TJR); however, it is unclear whether mood also improves. The current meta-analysis examined changes in depression and anxiety following TJR in older (≥50 years) patients in order to address this gap in the literature.

METHODS

Data from 26 studies (4045 TJR, 55 controls) that assessed depression and/or anxiety pre- and post-surgery in TJR patients, with or without a control group, were analyzed. Prevalence rates and Cohen's d effect sizes were used to evaluate changes in the prevalence and severity of depression/anxiety, respectively.

RESULTS

Approximately 23% of TJR patients had clinically significant levels of depression prior to surgery, which decreased to 13% one year later. The prevalence of anxiety could not be evaluated due to the limited available data. TJR patients did not show any clinically meaningful reductions in symptoms of depression or anxiety, following surgery. Compared to controls, there was no difference in symptom progression over time; although only one study examined this.

CONCLUSIONS

TJR patients appear to have higher rates of clinically significant symptoms of depression before and after surgery, compared to the general population, however more research with adequate control groups is needed to confirm this. Only a modest improvement in the severity of depression and anxiety symptoms was noted post-surgery. However, existing research is limited; preventing definite conclusions regarding the impact of TJR on mood.

Incidence of delirium following total joint replacement in older adults: a meta-analysis

OBJECTIVE

Delirium is common in older adults following total joint replacement (TJR) of the hip and knee. However, reports of the incidence of delirium vary widely, limiting their usefulness. The current meta-analysis therefore examined (1) the incidence of delirium in older patients who underwent TJR and (2) whether these rates vary according to the (a) joint (hip/knee replacement), (b) inclusion/exclusion of patients who underwent simultaneous bilateral surgery, (c) inclusion/exclusion of patients with preexisting cognitive impairments, (d) type of anesthesia (regional/general), (e) method/frequency of assessment, and (f) postoperative interval.

METHOD

Data from 24 studies (2,895 patients) that measured postsurgical delirium following TJR were analyzed. Mean weighted proportions were calculated using a random-effects model to assess the overall incidence of delirium and whether the rate varied according to the aforementioned variables.

RESULTS

Overall, 17% of patients who underwent TJR developed delirium during hospital admission. Individual estimates varied from 0% to 82%, but this variability was not adequately explained by the variables that were examined.

CONCLUSIONS

Delirium is relatively common following TJR; however, it remains unclear why individual estimates vary so widely. Health professionals working with these patients should remain alert to the presentation, diagnosis and management of delirium to optimize postsurgical outcomes.

The ontogeny of the chin: an analysis of allometric and biomechanical scaling

The presence of a prominent chin in modern humans has been viewed by some researchers as an architectural adaptation to buttress the anterior corpus from bending stresses during mastication. In contrast, ontogenetic studies of mandibular symphyseal form suggest that a prominent chin results from the complex spatial interaction between the symphysis and surrounding soft tissue and skeletal anatomy during development. While variation in chin prominence is clearly influenced by differential growth and spatial constraints, it is unclear to what degree these developmental dynamics influence the mechanical properties of the symphysis. That is, do ontogenetic changes in symphyseal shape result in increased symphyseal bending resistance? We examined ontogenetic changes in the mechanical properties and shape of the symphysis using subjects from a longitudinal cephalometric growth study with ages ranging from 3 to 20+ years. We first examined whether ontogenetic changes in symphyseal shape were correlated with symphyseal vertical bending and wishboning resistance using multivariate regression. Secondly, we examined ontogenetic scaling of bending resistance relative to bending moment arm lengths. An ontogenetic increase in chin prominence was associated with decreased vertical bending resistance, while wishboning resistance was uncorrelated with ontogenetic development of the chin. Relative to bending moment arm lengths, vertical bending resistance scaled with significant negative allometry whereas wishboning resistance scaled isometrically. These results suggest a complex interaction between symphyseal ontogeny and bending resistance, and indicate that ontogenetic increases in chin projection do not provide greater bending resistance to the mandibular symphysis.

The effect of elevated dietary cholesterol on pulmonary surfactant function in adolescent mice

It has been established that phospholipids and cholesterol interact in films of pulmonary surfactant (PS). Generally it is thought that phospholipids increase film stability whereas cholesterol increases film fluidity. To study this further, we modified dietary cholesterol in mice which received either standard rodent lacking cholesterol (sd), or high cholesterol (2%) diet (hc) for 1 month. Phospholipid stability was investigated by a capillary surfactometer (CS), which measures airflow resistance and patency. PS was collected by bronchiolar lavage and centrifuged to obtain the surface-active film (SAF). Results showed that the hc-SAF had significantly more cholesterol than sd-SAF. CS analyses at 37 degrees C showed no significance differences in airflow resistance between hc-SAF and sd-SAF. However, at 37 degrees C, sd-SAF showed greater ability to maintain patency compared to hc-SAF, whereas at 42 degrees C hc-SAF showed patency ability similar to sd-SAF. The results suggested that increased cholesterol in hc-SAF induced less stability in the SAF possibly due to cholesterol's fluidizing effect on phospholipids at physiological temperatures.

In vitro dissolution of tritium-loaded particles from the JET fusion machine

With the experimental evolution of fusion power the levels of tritium used will increase as will the potential for human exposure. Tritium-loaded carbon particles produced during the experimental operation of the Joint European Torus fusion tokamak have been characterised in terms of size, elemental composition and specific activity of tritium elsewhere. The aim of this study was to characterise the dissolution of tritium from these particles in order to derive dose coefficients for this material and provide guidance on monitoring procedures should it be inhaled accidentally. The dissolution of tritium was measured for 100 d in lung serum simulant from two batches of materials, SG1 and SG2, which were obtained from carbon tiles originating from different positions in the reactor. Retention over this period followed a three-component exponential. About 1-5% dissolved within a minute, and up to a further 20% dissolved over 100 d for the SG1 materials but <1% for the SG2 materials. Dissolution between the SG1 materials varied greatly, whereas the SG2 materials were similar. As a result of this variability, the assessed dose from urinary excretion could be in error by up to two orders of magnitude depending on the material inhaled. It is recommended that (i) the dissolution is measured for a wider range of materials, preferably dusts collected in working areas, and (ii) in vivo studies are performed to characterise fully the urine excretion of tritium from these materials. This information could be used to provide improved guidance on dose assessment after special or routine monitoring, taking account of the likely variation of particle size and biological retention half times.

Secondary structures in hyaluronan solutions: chemical and biological implications

Hyaluronan behaves as an unusually stiff polymer in solution. Periodate oxidation of the hexuronic acid moiety is severely hindered, as is that of chondroitin 4-sulphates and 6-sulphates. On the basis of X-ray and computer studies a secondary structure was proposed which accounted for the known facts. NMR data obtained subsequently in dimethyl sulphoxide were completely compatible with these proposals. Results obtained in H2O suggested that the acetamido group could not be oriented in aqueous solution as it was in dimethyl sulphoxide solution. There is strong evidence that an H2O bridge between the acetamido and carboxylate groups is involved in the secondary structure in H2O. It is suggested that conversion of one structure (stable in the absence of H2O) to the other (in aqueous solution) might occur during biosynthesis, as part of the driving force that results in shedding from the H2O-poor environment of the membrane. The hydrogen-bonded secondary structures show quite large arrays of contiguous CH groups, giving a hydrophobic character to some parts of the polymer, which might be significant in self-association and for interactions with membranes.

Proteoglycan-collagen interactions

Among the most important events in connective tissue physiology are the nucleation, growth and calcification of collagen fibrils. It has been speculated that all are associated with, or even controlled by collagen-proteoglycan interactions. We therefore developed methods for investigating these associations in tissues, particularly for understanding their significance for type I collagen, the commonest form of collagen in the body, especially predominant in bone. Using an electron-dense dye, Cupromeronic blue, in the 'critical electrolyte concentration' mode, and digestion by hyaluronidase, chondroitinase ABC or keratanase, supported by biochemical analyses, we found that dermatan sulphate proteoglycan of soft connective tissue (skin, tendon, cornea) was regularly and orthogonally arrayed at the fibril surface, at the d or e band. Keratan sulphate proteoglycan in the cornea associates orthogonally at the a and c bands. Bone, demineralized by a non-aqueous technique which retains proteoglycans in the tissue, does not contain orthogonal arrays; the interfibrillar proteoglycan filaments are oriented parallel to the fibril axis. The main proteoglycan in bone is chondroitin sulphate-rich. There are thus four separate specific binding sites on type I collagen fibrils, each one associating with one particular proteoglycan, and apparently no other. This implies that there are two corresponding binding sites in each proteoglycan. Available evidence shows that there are two species of small dermatan sulphate and keratan sulphate proteoglycans. It is suggested that each species is specific for its own band (a, c, d or e). Hyaluronate and chondroitin sulphate are probably mainly interfibrillar, acting in a space-filling capacity.

DNA fragmentation in developing lung fibroblasts exposed to Stachybotrys chartarum (atra) toxins

Stachybotrys chartarum (atra) is a toxic mold that grows on water-damaged cellulose-based materials. Research has revealed also that inhalation of S. chartarum spores caused marked changes in respiratory epithelium, especially to developing lungs. We analyzed the epigenetic potential of S. chartarum spore toxins on developing rat lung fibroblasts using single cell gel electrophoresis (comet assay). Isolated fetal lung fibroblasts were exposed to S. chartarum spore toxins for 15 min, 3, 14, or 24 hr and control cells were exposed to saline under the same conditions. Cells were embedded in agarose, electrophoresed under alkaline conditions and silver stained. DNA damage was assessed in terms of fragmentation as measured by comet tail length (DNA migration) and intensity (% DNA contained within head and tail). Upon visual inspection, control fibroblasts showed no DNA fragmentation whereas S. chartarum-treated cells had definable comets of various degrees depending upon the time-course. Analyses of the comets revealed that exposure to S. chartarum spore toxins for at least 15 min to 14 hr, induced increased DNA fragmentation in a time-dependent manner. The fact that exposure to toxins for 24 hr showed less damage suggested that developing lung fibroblasts may have the capability of repairing DNA fragmentation.

Anti-Müllerian hormone inhibits initiation of growth of human primordial ovarian follicles in vitro

BACKGROUND

Anti-Müllerian hormone (AMH) inhibits the initiation of the development and early growth of mouse ovarian follicles. Furthermore, the ovarian follicle pool diminishes prematurely in AMH-knockout mice. In this study, we examined whether AMH plays a similar role in humans, controlling ovarian follicle growth.

METHODS

Human ovarian cortical tissue biopsy specimens were cut into small pieces and cultured for 7 days in medium containing rat recombinant AMH at 0, 10, 30 or 100 ng/ml. The developmental stages and viability of the follicles were evaluated from histological sections.

RESULTS

Similar to previous studies, significant initiation of follicle growth was observed in almost all culture media, as demonstrated by a significantly smaller proportion of primordial follicles (14-26%) compared with non-cultured control tissue (56%). The exception was tissue in medium supplemented with AMH at 100 ng/ml. Here, the proportion of primordial follicles was not significantly different from that in non-cultured tissue; furthermore, it was significantly greater than that in vehicle control cultures and cultures containing AMH at 10 ng/ml, indicating the inhibition of growth initiation. Viability was unaffected by the presence of AMH when compared with tissues in control media.

CONCLUSIONS

Recombinant AMH at a concentration of 100 ng/ml has an inhibitory effect on early human ovarian follicular development in vitro, suppressing the initiation of primordial follicle growth.

Doses from the consumption of Cardiff Bay flounder containing organically bound tritium

ICRP dose coefficients for the ingestion of organically bound tritium (OBT) by adults and children are intended for general application to unspecified forms in diet and may not be applicable to intakes of a specific form of OBT. To obtain information relating to OBT in fish from Cardiff Bay, the retention of tritium in adult rats was determined after administration as either tritiated water (HTO) or dried flounder flesh containing OBT. Two components of retention were obtained in each case. The first component, attributable to tritium equilibrating with body water, had a half-time of retention of 3 days in each case, and accounted for 97% of the intake as HTO and 70% after intake of OBT in flounder. Results were consistent with rapid catabolism of a large proportion of flounder OBT to HTO. The second component of retention, attributable to OBT in rat tissues, accounted for 3% of tritium intake as HTO and 30% after intake as flounder OBT; the half-times of retention were 10 days and 25 days, respectively. The results obtained after administration as HTO are consistent with published animal data and correlate with the ICRP assumptions for adult man of half-times of 10 days for 97% behaving as HTO in body tissues and 40 days for 3% incorporated into OBT in body tissues. The results obtained after administration of flounder OBT suggest that appropriate assumptions for retention in adult man are 70% with a 10 day half-time and 30% with a 100 day half-time. These assumptions result in an ingestion dose coefficient of 6 x 10(-11) Sv Bq(-1). This compares with the ICRP value for OBT ingestion by adults of 4.2 x 10(-11) Sv Bq(-1), based on half-times of 10 days and 40 days applied to equal proportions of retained tritium. It is proposed that a dose coefficient of 6 x 10(-11) Sv Bq(-1) should be applied to tritium in flounders from Cardiff Bay. It is further proposed that this dose coefficient should be applied to all ingestion intakes by adults relating to this source of exposure, unless specific information is available showing that a significant proportion of the intake is HTO. The same proposals apply to dose coefficients derived here for flounder OBT consumption by children.

Stachybotrys chartarum alters surfactant-related phospholipid synthesis and CTP:cholinephosphate cytidylyltransferase activity in isolated fetal rat type II cells

Stachybotry chartarum, a fungal contaminant of water-damaged buildings commonly grows on damp cellulose-containing materials. It produces a complex array of mycotoxins. Their mechanisms of action on the pulmonary system are not entirely clear. Previous studies suggest spore products may depress formation of disaturated phosphatidylcholine (DSPC), the major surface-active component of pulmonary surfactant (PS). If S. chartarum can indeed affect formation of this phospholipid, then mold exposure may be a significant issue for pulmonary function in both mature lung and developing fetal lung. To address this possibility, fetal rat type II cells, the principal source of DSPC, were used to assess effects of S. chartarum extract on formation of DSPC. Isolated fetal rat lung type II cells prelabeled with 3H-choline and incubated with spore extract showed decreased incorporation of 3H-choline into DSPC. The activity of CTP:cholinephosphate cytidylyltransferase (CPCT), the rate-limiting enzyme in phosphatidylcholine synthesis was reduced by approximately 50% by a 1:10 dilution of spore extract. Two different S. chartarum extracts (isolates from S. chartarum (Cleveland) and S. chartarum (Hawaiian)) were used to compare activity of CPCT in the presence of phosphatidylglycerol (PG), a known activator. PG produced an approximate two-fold increase in CPCT activity. The spore isolate from Hawaii did not alter enzyme activity. S. chartarum (Cleveland) eliminated the PG-induced activation of CPCT. These results support previous observations that mold products alter PS metabolism and may pose a risk in developing lung, inhibiting surfactant synthesis. Different isolates of the same species of fungus are not equivalent in terms of potential exposure risks.

Medium-term dexa analysis of an uncemented femoral component

We investigated the bone remodelling around the AML uncemented femoral component using DEXA analysis and plain radiography in 19 patients at a mean of 89 months from operation. All patients had previously been analysed at a mean of 32 months after surgery. We found a decrease in bone mineral density around the AML implant between the two scans in Gruen zones 1,2 and 6 of up to 8%, but an increase in zones 4,5 and 7 of up to 36%. The increase in zones 4 and 5 were statistically significant (P>0.05). The relative difference between the operated and unoperated hips also showed a reduction in the bone density ratio with time, except in zones 4 and 5 where an increase was seen. We confirm the results of previous studies of proximal stress shielding and distal loading around the AML implant and demonstrate that bone remodelling continues in the medium term. (Hip International 2004; 14: 182-8).

Elasticity in extracellular matrix 'shape modules' of tendon, cartilage, etc. A sliding proteoglycan-filament model

Connective tissues (CTs), which define bodily shape, must respond quickly, robustly and reversibly to deformations caused by internal and external stresses. Fibrillar (elastin, collagen) elasticity under tension depends on molecular and supramolecular mechanisms. A second intra-/inter-molecular pair, involving proteoglycans (PGs), is proposed to cope with compressive stresses. PG interfibrillar bridges ('shape modules'), supramolecular structures ubiquitously distributed throughout CT extracellular matrices (ECMs), are examined for potential elastic properties. L-iduronate residues in shape module decoran PGs are suggested to be molecular springs, cycling through alternative conformations. On a larger scale, anionic glycosaminoglycan (AGAG) interfibrillar bridges in shape modules are postulated to take part in a sliding filament (dashpot-like) process, which converts local compressions into disseminated tensile strains. The elasticity of fibrils and AGAGs, manifest at molecular and larger-scale levels, provides a graduated and smooth response to stresses of varying degrees. NMR and rheo NMR, computer modelling, electron histochemical, biophysical and chemical morphological evidence for the proposals is reviewed.

The first and second 'laws' of chemical morphology, exemplified in mammalian extracellular matrices

Tissues are supramolecular organisations. The permanent and semi-permanent biopolymers therein function collaboratively in specifically bonded frameworks of macromolecules according to the physico-chemical laws that govern the behaviour of all molecules. In this paper two 'laws' or principles are discussed which give insights into the development and function of tissues, particularly the extracellular matrices (ECMs) of connective tissues. The first 'law' is qualitative;- The shape of a tissue is implicit in the shapes of the biopolymers from which it is constructed. The tissue biopolymers are jigsaw pieces, if they don't fit precisely, there is no picture. The second 'law' is quantitative;-The composition of a tissue is determined by the stable, specific interactions between the macromolecules of which it is constructed. These basic ideas underlie the discipline of chemical morphology. The term chemical morphology implies both the chemistry of shape and the shape of chemicals. The first meaning is well exemplified in the ECMs of connective tissues, in which the shape of an organism is defined and maintained. Specific relationships between the fibrillar (collagenous) components and the soluble polymers (proteoglycans) are set in the context of the first law. Tissue electron histochemistry (the morphology of the tissue) and knowledge of secondary and tertiary structures of the participating biopolymers (the shapes of the chemicals) together provide a model susceptible to quantitative testing. Simple calculation shows that the amount of any ligand (e.g. a proteoglycan) specifically bound at a single binding site per unit of collagen fibril length (the D period) increases linearly with the fibril diameter. Given the amount of collagen (measured as hydroxyproline) and its density, the constant of proportionality is approximately 42. Comparisons of the quantitative relationship between collagen and proteoglycans predicted from the model agree well with those obtained by biochemical analyses of different tendons from three species at all stages of development. Thus, the second 'law' appears to hold in this case.

Tetrahydrocannabinol (THC) alters synthesis and release of surfactant-related material in isolated fetal rabbit type II cells

Over the years, there has been a great deal of interest in the biological consequences of marijuana use. While evidence indicates that cannabinoids may have therapeutic uses in alleviating certain disease discomfort, there is little recent information on potential health risks, particularly related to the developing fetus. The present study was undertaken to determine the effects of delta 9-tetrahydrocannabinol (THC), the major psychoactive component in marijuana on fetal lung development specifically related to surfactant production. The rationale for the choice of this model lies in the importance of adequate lung development and surfactant production for the successful transition of the fetus to an air-breathing environment. Lung type II cells, the source of pulmonary surfactant, were isolated from fetal rabbit lungs on the 24th gestational day and incubated concurrently with various concentrations of THC and [3H]choline to label disaturated phosphatidylcholine (DSPC) the major surface-active phospholipid of surfactant. Under these conditions THC significantly reduced radiolabelling of DSPC and at the highest concentration (10(-4) M) induced release of DSPC. Pulse-chase studies were also conducted. Cells were prelabelled with [3H]choline, removed to fresh medium with THC (10(-4) M) and incubated for various time periods. Aqueous- and organic-soluble intermediates of DSPC formation were isolated. THC induced a significant increase in radiolabelling of CDPcholine, the rate-limiting conversion in DSPC synthesis. Radiolabelling of total phosphatidylcholine and DSPC was also significantly increased. Assay of CTP: cholinephosphate cytidylyltransferase which enzymatically converts cholinephosphate to CDPcholine showed that THC and phosphatidylglycerol (PG) both induced activation of the enzyme in fetal lung cytosol but not in the membranes. This effect of THC and PG was not additive. THC activated the enzyme only in fetal and not adult rabbit lung. The ability of THC to induce release of surfactant related material was also examined. In cells prelabelled with [3H]choline, THC induced release of [3H]DSPC in both cultured and freshly isolated fetal type II cells. These results suggest THC reduces formation of surfactant DSPC, probably through alterations in membrane dynamics. However, intracellular THC may actually increase formation of DSPC through an effect on the rate-limiting enzyme. THC also increases release of previously formed surfactant-related material.

The influence of congenital heart disease on survival of infants with oesophageal atresia

OBJECTIVE

To examine the prevalence of congenital heart disease in babies with oesophageal atresia and its influence on outcome.

DESIGN

Retrospective analysis.

SETTING

The resident population of one health region.

RESULTS

A total of 153 babies with oesophageal atresia were identified from 509 975 live births (0.30 per 1000); 26 (17%) had cardiac defects. Survival of babies with normal hearts was 97%, 97%, and 95% at one week, one month, and one year. Survival of babies with congenital heart disease was 85%, 85%, and 67% at one week, one month, and one year, but only one of ten deaths was the result of the congenital heart disease. The remaining deaths were due to other congenital malformations, respiratory disease, or chromosome abnormalities.

CONCLUSIONS

There is a high prevalence of congenital heart disease in babies with oesophageal atresia. Congenital heart disease is associated with a higher mortality in oesophageal atresia but it is not the cause of it.

Inhibition of prostaglandin synthesis and its effect on uterine activity during established premature labor in sheep

OBJECTIVE

Continuous infusion of the selective prostaglandin synthase type-2 inhibitor nimesulide, together with the oxytocin receptor antagonist atosiban, inhibits glucocorticoid induction of labor in sheep. We evaluated the effectiveness of this treatment commencing after the onset of premature labor when prostaglandin concentrations are already significantly elevated.

METHODS

Premature labor was induced in chronically cannulated fetuses by constant fetal dexamethasone infusion. After the onset of active labor in each ewe, defined as uterine electromyographic (EMG) activity twice basal levels, ewes received combined nimesulide and atosiban (20.0 and 4.12 mg/kg per day, respectively; n = 6) or vehicle (n-methyl-2-pyrrolidone and saline each 1 mL/hour; n = 4) infusions for 48 hours. Maternal and fetal plasma PGFM (13,14-dihydro-15-keto PGF2alpha, the stable metabolite of prostaglandin (PG) F2alpha) and PGE2 concentrations were measured before, during, and after infusions.

RESULTS

Four nimesulide- and atosiban-treated ewes successfully completed the 48-hour infusion period with no deliveries occurring during inhibitor treatment, or up to 6 hours after inhibitor treatment. Delivery was delayed in two other ewes, compared with control animals. Uterine EMG activity in nimesulide- and atosiban-treated ewes (n = 4) was significantly reduced during the 48-hour inhibitor treatment period. Maternal and fetal prostaglandin concentrations were significantly decreased in inhibitor-treated ewes during and after the infusions.

CONCLUSIONS

The combination of nimesulide and atosiban treatment for 48 hours successfully inhibited the progression of active premature labor to delivery. This study further supports the potential value of this treatment regime for the inhibition of premature labor.

Development of an Internally Quenched Fluorescent Substrate and a Continuous Fluorimetric Assay for Streptococcus pneumoniae Signal Peptidase I

Signal peptidase (SPase) I is responsible for the cleavage of signal peptides of many secreted proteins in bacteria and serves as a potential target for the development of novel antibacterial agents due to its unique physiological and biochemical properties. In this paper, we describe a novel fluorogenic substrate, KLTFGTVK(Abz)PVQAIAGY(NO2)EWL, in which 2-aminobenzoic acid (Abz) and 3-nitrotyrosine (Y(NO2)) were used as the fluorescent donor and acceptor, respectively. The substrate can be cleaved by both Streptococcus pneumoniae and Escherichia coli SPase I. Upon cleavage of the fluorogenic substrate by SPase I, the fluorescent intensity increases and can be monitored continuously by spectrofluorometer. Kinetic analysis with S. pneumoniae SPase I demonstrated that the K(m) value for the substrate is 118.1 microM, and the k(cat) value is 0.032 s(-1). Mass spectrometric analysis and peptide sequencing of the two cleaved products confirmed that the cleavage occurs specifically at the predicted site. More interestingly, the positively charged lysine in the N-terminus of the substrate was demonstrated to be important for effective cleavage. Phospholipids were found to stimulate the cleavage reaction. This stimulation by phospholipids is dependent upon the N-terminal charge of the substrate, indicating that the interaction of the positively charged substrate with anionic phospholipids is important for maintaining the substrate in certain conformation for cleavage. The substrate and assay described here can be readily automated and utilized for the identification of potential antibacterial agents.

Structure and function in extracellular matrices depend on interactions between anionic glycosaminoglycans

Connective tissue extracellular matrices define and maintain shape. Collagen fibrils transmit and resist pulling forces and soluble interfibrillar carbohydrate-rich polymers (anionic glycosaminoglycans AGAGs) resist compressive forces. This article shows that AGAGs (chondroitin, dermochondan and keratan sulphates) form supramolecular organisations which take tensile stresses as well, helping to maintain shape as part of 'shape modules'. Specific interactions with collagen fibrils tie down the AGAGs but conversely they orientate and maintain the organisation of collagen fibrils by forming interfibrillar bridges. The shapes of the AGAG chains in solution, shown by NMR to be two-fold helices, are completely complementary, allowing duplexes and higher aggregates to form spontaneously, providing participating AGAGs are oriented head-to-head i.e. antiparallel to each other. These tertiary structures are exact analogues of the beta-sheets are the basic structure of the interfibrillar bridges in the shape modules. In the absence of key shape module components, in a genetic disorder, extracellular matrices do not form an ordered tissue.

Periprosthetic bone mineral density changes with femoral components of differing design philosophy

We measured the bone mineral density in 22 patients with the cylindrical stemmed cobalt-chrome AML prosthesis (collared) and in 22 patients with the tapered stem titanium CLS prosthesis (collarless). DEXA scanning was undertaken at a mean of 40 months in the AML and 52 months in the CLS group from the time of implant insertion. In both groups the greatest mean loss of BMD was found in Gruen zone 7 and the least change in Gruen zone 5. In all zones the BMD loss was greater in the AML group but only statistically significant in zones 6 (P<0.05) and 7 (P<0.01). Although numerous factors affect BMD changes around cementless implants, this study suggests that less bone loss can be associated with the titanium CLS stem.

Analysis of pulmonary surfactant by Fourier-transform infrared spectroscopy following exposure to Stachybotrys chartarum (atra) spores

Lung cells are among the first tissues of the body to be exposed to air-borne environmental contaminants. Consequently the function of these cells may be altered before other cells are affected. As gas exchange takes place in the lungs, changes in cellular function may have serious implications for the processes of oxygen uptake and carbon dioxide elimination. In order for these processes to occur, the lung must maintain a high degree of expandability. This latter function is accomplished in part by the pulmonary surfactant which is synthesized and released by alveolar type II cells. Earlier studies have shown that exposure to gas phase materials such as smoke or organic solvents can alter the composition and function of the surfactant. The present study examines the ability of highly toxigenic mold spores to alter surfactant composition. Stachybotrys chartarum spores suspended in saline were instilled into mouse trachea as described earlier. After 24 h, the lungs were lavaged and the different processing stages of surfactant isolated by repeated centrifugation. Intracellular surfactant was isolated from the homogenized lung tissue by centrifugation on a discontinuous sucrose gradient. Samples were extracted into chloroform-methanol, dried and analyzed by Fourier-Transform infrared spectroscopy (FTIR). Exposure to S. chartarum induced an overall reduction of phospholipid among the three surfactant subfractions. The intermediate and spent surfactant fractions in particular were reduced to about half of the values observed in the saline-treated group. The relative distribution of phospholipid was also altered by spore exposure. Within the intracellular surfactant pool, higher levels of phospholipid were detected after spore exposure. In addition, changes were observed in the nature of the phospholipids. In particular strong intramolecular hydrogen bonding, together with other changes, suggested that spore exposure was associated with absence of an acyl chain esterified on the glycerol backbone, resulting in elevated levels of lysophospholipid in the samples. This study shows that mold spores and their products induce changes in regulation of both secretion and synthesis of surfactant, as well as alterations in the pattern of phospholipid targeting to the pulmonary surfactant pools.

Antenatal renal pelvic measurements: what do they mean?

OBJECTIVE

To analyse data on cases with urological abnormalities recorded over a 15-year period (1984-98) by the Northern Region Congenital Abnormality Survey (NorCAS), with special reference to fetal renal pelvic measurements.

MATERIALS AND METHODS

Data on all urological cases recorded in the NorCAS database and in notification documents forwarded from hospitals in the Northern Region were extracted and incorporated in a separate unattributable database for analysis. Specific fields for filing recorded fetal renal pelvic measurements with their corresponding gestational ages were inserted; it was ensured as far as possible that these measurements were made in the anteroposterior plane.

RESULTS

The total number of cases analysed was 2737; a measurement of the fetal renal pelvis was recorded in 813, and more than once in 468, giving 1301 measurement episodes with the corresponding gestational ages, pregnancy and postnatal outcome. The male/female (M/F) ratio was significantly higher in those cases which had a fetal renal pelvic measurement recorded than in those which had not. This was because there was a 12/1 M/F ratio in measured cases of vesico-ureteric reflux (VUR). Few cases of VUR had a fetal renal pelvic measurement recorded. The difference in the fetal renal pelvic measurements between those cases which were normal postnatally and those which had a structural abnormality, an obstructive lesion or VUR became significant at 7 mm and at 18 weeks of gestational age. Over the whole period the proportion of cases in which micturating cysto-urethrography was technically possible and might have contributed to the diagnosis was 28.5%; the highest was 44.1% in 1998.

CONCLUSIONS

Antenatal renal dilatation occurs infrequently in the presence of VUR and when it does, the fetus will probably be male. Antenatal ultrasonography is unlikely to contribute to detecting VUR in females, the gender in whom early diagnosis is particularly desirable. Other means of suspecting VUR antenatally, e.g. the family history or genetic coding, may be more valuable. A measurement of the fetal renal pelvis of > or = 7 mm at a gestational age of 18 weeks should prompt subsequent careful ultrasonography during the pregnancy and early postnatal investigation of the urinary tract. The diagnosis of VUR should not be excluded because the fetal renal pelvis is only minimally dilated if the fetus is female.

Interaction between herpes simplex virus type 1 IE63 protein and cellular protein p32

The herpes simplex virus type 1 (HSV-1) immediate-early gene IE63 (ICP27), the only HSV-1 regulatory gene with a homologue in every mammalian and avian herpesvirus sequenced so far, is a multifunctional protein which regulates transcriptional and posttranscriptional processes. One of its posttranscriptional effects is the inhibition of splicing of viral and cellular transcripts. We previously identified heterogeneous nuclear ribonucleoprotein (hnRNP) K and casein kinase 2 (CK2) as two protein partners of IE63 (H. Bryant et al., J. Biol. Chem. 274:28991-28998, 1999). Here, using a yeast two-hybrid assay, we identify another partner of IE63, the cellular protein p32. Confirmation of this interaction was provided by coimmunoprecipitation from virus-infected cells and recombinant p32 binding assays. A p32-hnRNP K-CK2 complex, which required IE63 to form, was isolated from HSV-1-infected cells, and coimmunoprecipitating p32 was phosphorylated by CK2. Expression of IE63 altered the cytoplasmic distribution of p32, with some now colocalizing with IE63 in the nuclei of infected and transfected cells. As p32 copurifies with splicing factors and can inhibit splicing, we propose that IE63 together with p32, possibly with other IE63 partner proteins, acts to disrupt or regulate pre-mRNA splicing. As well as contributing to host cell shutoff, this effect could facilitate splicing-independent nuclear export of viral transcripts.

Effects of Stachybotrys chartarum (atra) conidia and isolated toxin on lung surfactant production and homeostasis

This study evaluated the effects of Stachybotrys chartarum conidia and a trichothecene, isosatratoxin-F, on choline incorporation into DSPC by fetal rabbit alveolar type II cells and on alveolar surfactant subtypes in mice. Exposure of fetal rabbit type II cells to S. chartarum conidia at concentrations of 10(3) to 10(6) conidia ml(-1) significantly depressed [3H] choline incorporation after 24 h of exposure. Exposure of the rabbit cells to 10(5) to 10(6) conidia ml(-1) also resulted in significantly depressed [3H] choline uptake after 48 h. Additionally, fetal rabbit alveolar type II cells exposed to isosatratoxin-F in concentrations ranging from 10(-9) to 10(-4) M showed a significant reduction in [3H] choline incorporation into DSPC. Alveolar surfactant phospholipid concentrations in the different metabolic subfractions of lung lavage fluid of mice intratracheally exposed to either 50 microl of 10(7) ml(-1) S. chartarum conidia or 50 microl 10(-7) M isosatratoxin-F showed some significant changes at 12, 24, 48, and 72 h post-exposure, compared to the surfactant subfractions of control mice which were either untreated, exposed to saline or to 50 microl of 10(-7) ml(-1) Cladosporium cladosporioides conidia. In both the S. chartarum- and the isosatratoxin-F-treated mice, exposure significantly increased P10, P100, and S100 phospholipid concentrations, while the P60 phospholipid concentrations were depressed. In contrast, C. cladosporioides-treated mice showed only one significant change in subfraction phospholipid concentration: P60 was depressed at 48 h post-exposure. These results reveal that alveolar type II cells are sensitive to exposure to S. chartarum conidia and to isosatratoxin F. Sensitivity is manifest by alterations in the normal metabolic processing of alveolar surfactant. In exposed mice, this effect appears to involve a significant increase in newly secreted surfactant and an accumulation of the used surfactant forms.

The effect of epidermal growth factor on the fetal rabbit mandibular condyle and isolated condylar fibroblasts

The load-bearing surface of the mandibular condyle presents a unique arrangement of tissues consisting of an avascular layer composed largely of collagen bundles. Fibroblasts are interspersed amongst these bundles and are generally agreed to produce the collagen. The mechanisms controlling development of these tissues have not been determined. This study was conducted to explore the role of epidermal growth factor (EGF), which appears to be important in the development of many oral tissue types as well as in the growth and differentiation of the mandibular condyle. Superficial cells of the fibrous zone of the condyle were isolated from fetal rabbit condyles and [(3)H]thymidine incorporation into DNA measured. The application of EGF produced a significant increase in radiolabel incorporation after 2 days compared to 4 days in the controls, suggesting that EGF induced cells to enter S-phase more rapidly. Fetal condyles were also cultured on gelfoam surgical sponges for up to 21 days. Autoradiography of cultured condyles showed that cells of all three zones may potentially replicate, as indicated by incorporation of [(3)H]thymidine. All three regions displayed greater increases in cell numbers in samples exposed to EGF than in control samples. The measurement of zone thickness in condyles cultured on gelfoam sponges with or without EGF showed that this peptide was able to re-establish thickness, bringing it in line with the relation observed when the condyles were isolated initially, particularly of the intermediate zone over a period of 21 days. As very little autoradiographic labelling occurred at this time-point in any of the zones, the increase in thickness must primarily be due to matrix production. It is concluded that EGF is one factor potentially regulating both replication and differentiation in mandibular condyle and its associated cells.

Socioeconomic inequalities in risk of congenital anomaly

AIMS

To investigate socioeconomic inequalities in the risk of congenital anomalies, focusing on risk of specific anomaly subgroups.

METHODS

A total of 858 cases of congenital anomaly and 1764 non-malformed control births were collected between 1986 and 1993 from four UK congenital malformation registers, for the purposes of a European multicentre case control study on congenital anomaly risk near hazardous waste landfill sites. As a measure of socioeconomic status, cases and controls were given a value for the area level Carstairs deprivation index, by linking the postcode of residence at birth to census enumeration districts (areas of approximately 150 households).

RESULTS

Risk of non-chromosomal anomalies increased with increasing socioeconomic deprivation. The risk in the most deprived quintile of the deprivation index was 40% higher than in the most affluent quintile. Some malformation subgroups also showed increasing risk with increasing deprivation: all cardiac defects, malformations of the cardiac septa, malformations of the digestive system, and multiple malformations. No evidence for socioeconomic variation was found for other non-chromosomal malformation groups, including neural tube defects and oral clefts. A decreasing risk with increasing deprivation found for all chromosomal malformations and Down's syndrome in unadjusted analyses, occurred mainly as a result of differences in the maternal age distribution between social classes.

CONCLUSION

Our data, although based on limited numbers of cases and geographical coverage, suggest that more deprived populations have a higher risk of congenital anomalies of non-chromosomal origin and some specific anomalies. Larger studies are needed to confirm these findings and to explore their aetiological implications.

The multifunctional herpes simplex virus IE63 protein interacts with heterogeneous ribonucleoprotein K and with casein kinase 2

Herpes simplex virus type 1 (HSV-1), the prototype alpha-herpesvirus, causes several prominent diseases. The HSV-1 immediate early (IE) protein IE63 (ICP27) is the only regulatory gene with a homologue in every mammalian and avian herpesvirus sequenced so far. IE63 is a multifunctional protein affecting transcriptional and post-transcriptional processes, and it can shuttle from the nucleus to the cytoplasm. To identify interacting cellular proteins, a HeLa cDNA library was screened in the yeast two-hybrid system using IE63 as bait. Several interacting proteins were identified including heterogeneous nuclear ribonucleoprotein K (hnRNP K), a multifunctional protein like IE63, and the beta subunit of casein kinase 2 (CK2), a protein kinase, and interacting regions were mapped. Confirmation of interactions was provided by fusion protein binding assays, co-immunoprecipitation from infected cells, and CK2 activity assays. hnRNP K co-immunoprecipitated from infected cells with anti-IE63 serum was a more rapidly migrating subfraction than hnRNP K immunoprecipitated by anti-hnRNP K serum. Using anti-IE63 serum, both IE63 and hnRNP K were phosphorylated in vitro by CK2, while in immunoprecipitates using anti-hnRNP K serum, IE63 but not hnRNP K was phosphorylated by CK2. These data provide important new insights into how this key viral regulatory protein exerts its functions.

Screening for fetal urological abnormalities: how effective?

OBJECTIVE

To analyse urological cases registered with the Northern Congenital Abnormality Survey (NorCAS) and thus assess antenatal diagnostic sensitivity, measure regional interhospital variation and determine whether antenatal ultrasonography has contributed to the prevention of urinary tract disease in childhood.

METHODS

All notification documents forwarded to NorCAS from its inception in 1984 until 31 December 1996 were inspected and those relating to urological abnormalities were abstracted. Information about postnatal progress was often missing. Twenty-three hospitals delivering maternity services were identified and randomly allocated a code letter a-w. Data were analysed in two periods, 1984-90 and 1991-96. To quantify hospital performance an 'expected number' for each hospital was calculated from the overall incidence per 1000 births and the number of births in each hospital.

RESULTS

There was a clear improvement in antenatal diagnostic sensitivity for the major urological abnormalities in the second period, but there was considerable variation among hospitals in the number of cases notified; this applied particularly to antenatal renal dilatation. Two hospitals notified significantly more cases in this category than all the others. The difference in notification rates among hospitals was caused by diagnoses such as vesico-ureteric reflux (VUR), pelvi-ureteric junction obstruction and megaureter, which often produce antenatal renal dilatation. Hospitals which notified more of these cases performed more micturating cystograms and identified more children with VUR. Measurements of the fetal renal pelvis were regularly made by only seven hospitals; one of these had difficulties with postnatal follow-up. There was evidence that moderate degrees of antenatal renal dilatation (4-10 mm) were associated with VUR; 8.5% of the children in whom VUR was diagnosed had fetal renal dilatation of this order.

CONCLUSION

Antenatal renal dilatation and its significance are either not being recognized or not appreciated in some hospitals. The high incidence of VUR in cases with moderate antenatal renal dilatation indicates that children with this condition may be escaping diagnosis.

Severe polyethylene wear in uncemented acetabular cup system components: a report of 5 cases

We report 5 cases of severe failure of the polyethylene liner at 4 to 7.4 years after uncemented anatomic medullary locking (AML) total hip arthroplasty, using the acetabular cup system (ACS). The mode of failure was by a combination of wear-through to the metal backing and liner fracture. Four of the 5 cases were associated with a 32-mm head. The ACS design is flawed because of a lack of hemispherical geometry resulting in rim loading on a region of the liner that has the thinnest polyethylene. All patients with this type of implant should be monitored for evidence of excessive polyethylene wear.

Hyaluronan forms specific stable tertiary structures in aqueous solution: a 13C NMR study

13C NMR spectra of aqueous solutions of hyaluronan (HA) of high molecular mass, before and after digestion with testicular hyaluronidase, and of hyaluronan methyl ester were obtained at 125.8 MHz. Carbonyl peaks were assigned by using selective decoupling techniques. Spectra of digested and undigested HA showed sharp signals, except for that assigned to the acetamido carbonyl carbon in the high polymer, which was much broadened. The decreased mobility of this C==O, thus demonstrated, was caused by restricted rotation. As part of the rigid CO---NH unit, rotation of NH was therefore similarly restricted, probably because of an intermolecular H bond from NH to carboxylate groups on neighbouring HA molecules. This bond was confirmed by comparing esterified HA with unmodified HA. Methyl esterification of carboxylates was accompanied by changes in acetamido C==O resonances consistent with increased mobility of CO---NH groups. Ester C==O resonances were sharp, proving that they did not participate in sterically restricted structures such as the proposed H bonds involving unesterified carboxylate groups. C==O resonances report on the environments and on the interrelationships of amide and carboxylate groups. A detailed structure suggested for high-molecular-mass HA in aqueous solution takes account of NMR and x-ray fiber diffraction data. Antiparallel HA chains overlap in meshworks stabilized by specific H bonds and hydrophobic bonds. This highly cooperative structure, formally equivalent to beta-sheets seen in proteins, is not stable in low-molecular-mass HA solution. The results relate to structures proposed for shape modules in extracellular matrix involving chondroitin and keratan sulfates, which resemble HA in their stereochemistry.

A survey of state insurance mandates covering alcohol and other drug treatment

This article reports the results of a survey of health insurance mandate legislation for alcohol and other drug treatment in the 50 states through spring 1991. A total of 23 states (including the District of Columbia) requires insurance carriers to provide coverage for alcohol and other drug treatment. This paper compares the provisions in these states at the present time and contrasts these provisions with those in effect in 1981. The paper concludes with a discussion of the policy objectives states pursue through enactment of such legislation and the outcomes brought about by the mandates.

How rational histochemistry produced order out of chaos in the "amorphous ground substance" (with a little help from biochemistry, biophysics etc.)

From an amorphous ground substance containing polymers of unknown composition arranged in no particular pattern we have in about 50 years arrived at a proposal where the very shape of the tissue and hence of the organism is determined by newly discovered structures, the shape modules, in the ground substance, which were demonstrated by histochemical techniques interpreted on rational biophysical and chemical principles.

Calcium-PS-dependent protein kinase C and surfactant protein A in isolated fetal rabbit type II alveolar cells and surfactant-related material

The fetal lung secretes significant quantities of surfactant during late gestation to prepare for initiation of respiration at birth. However, the mechanism by which this occurs has not been determined. Since Ca2+-phosphatidylserine (PS)-dependent protein kinase C has been implicated in surfactant secretion in adult lung, the present study was done to determine whether this enzyme is also involved in the initiation of surfactant release from fetal type II cells. Type II cells isolated from gestational day-24 fetal rabbits were used. Cells were prelabelled with [32P] and [3H]choline and exposed to 4beta phorbol ester (10(-5) M) for 2 h. Secretion product and subcellular fractions were isolated by removing the culture medium, mixing with homogenate from adult rabbit lung, and subfractionating by centrifugation on a sucrose gradient. Samples of secretion product were also prepared for electron microscopy. Ca2+-PS-dependent protein kinase C was also assayed in some samples, and an add-back technique was used to determine whether enzyme activity in the intracellularly stored surfactant fraction was due to contamination. The results showed that material released by fetal type II cells after exposure to phorbol ester coprecipitated with adult rabbit lung lamellar bodies and microsomes. Morphologically, a range of forms, including lamellar-body-like structures, was detected. The released material originated largely from the lamellar body compartment of the fetal type II cells and displayed immunoreactivity with antibody to surfactant protein A (SP-A) at 35 and 70 kDa apparent molecular mass. Assay of protein kinase C in fetal type II cells showed that exposure to conditioned medium, which induces differentiation, increased activity. Incubation with phorbol ester induced translocation of activity to the microsomal fraction. Add-back assays suggested that protein kinase C activation by treatment with phorbol ester induced translocation of enzyme activity to the lamellar body fraction; none was detected prior to treatment. These results support a role for Ca2+-PS-dependent protein kinase C in initiation of surfactant release by interaction with the developing lamellar body compartment in fetal type II cells.

The blistering diseases

The intent and purpose of the authors is to familiarize the reader with the principles that govern the diagnosis and management of autoimmune mucocutaneous blistering diseases. The purpose was not to be all-inclusive but illustrative. There are several other blistering diseases that have not been discussed because of the limited scope of this article. Of these, toxic epidermal necrolysis, erythema multiforme, and the like warrant the same attention and early recognition. These are covered in different articles. For the same reasons, certain genetically linked blistering diseases have not been discussed.

Human cells unable to express decoron produced disorganized extracellular matrix lacking "shape modules" (interfibrillar proteoglycan bridges)

The shapes of extracellular matrices are determined by positioning collagen fibrils in the right places, oriented and maintained viv-à-vis each other. The fibrils are linked orthogonally by dermatan/chondroitin sulfates or keratan sulfate (in small proteoglycans) attached every approximately 65 nm via their protein moieties to collagen fibrils at specific binding sites. These regular repeating structures are the "shape modules." The characteristic arrays of orthogonal interfibrillar bridges were missing and the extracellular matrix was totally disorganized in matrices produced by fibroblasts taken postmortem from skin of an electively aborted fetus which did not express decoron in culture, thus supporting the shape module hypothesis. Biglycon, dermatan sulfate, heparan sulfate, collagen, and hyaluronan were produced by these cells but did not contribute to a normal extracellular matrix. A similar electron histochemical and biochemical survey of extracellular matrices produced by seven normal and eight osteogenesis imperfecta cell lines from donors of different ages and both sexes showed no comparable disruptions of their matrices. This investigation appears to be the first to demonstrate systematically proteoglycan:collagen interactions in matrices produced by cultured human cells.

Risk of congenital anomalies near hazardous-waste landfill sites in Europe: the EUROHAZCON study

BACKGROUND

Waste-disposal sites are a potential hazard to health. This study is a multicentre case-control study of the risk of congenital anomalies associated with residence near hazardous-waste landfill sites in Europe.

METHODS

We used data from seven regional registers of congenital anomalies in five countries. We studied 1089 livebirths, stillbirths, and terminations of pregnancy with non-chromosomal congenital anomalies and 2366 control births without malformation, whose mothers resided within 7 km of a landfill site; 21 sites were included. A zone within 3 km radius of each site was defined as the "proximate zone" of most likely exposure to teratogens.

FINDINGS

Residence within 3 km of a landfill site was associated with a significantly raised risk of congenital anomaly (295 cases/511 controls living 0-3 km from sites, 794/1855 living 3-7 km from sites; combined odds ratio 1.33 [95% CI 1.11-1.59], adjusted for maternal age and socioeconomic status). There was a fairly consistent decrease in risk with distance away from the sites. A significantly raised odds ratio for residence within 3 km of a landfill site was found for neural-tube defects (odds ratio 1.86 [1.24-2.79]), malformations of the cardiac septa (1.49 [1.09-2.04]), and anomalies of great arteries and veins (1.81 [1.02-3.20]). Odds ratios of borderline significance were found for tracheo-oesophageal anomalies (2.25 [0.96-5.26]), hypospadias (1.96 [0.98-3.92]), and gastroschisis (3.19 [0.95-10.77]). There was little evidence of differences in risk between landfill sites but power to detect such differences was low.

INTERPRETATION

This study shows a raised risk of congenital anomaly in babies whose mothers live close to landfill sites that handle hazardous chemical wastes, although there is a need for further investigation of whether the association of raised risk of congenital anomaly and residence near landfill sites is a causal one. Apparent differences between malformation subgroups should be interpreted cautiously.

The structure of interfibrillar proteoglycan bridges (shape modules') in extracellular matrix of fibrous connective tissues and their stability in various chemical environments

Collagen fibrils in extracellular matrices of connective tissues (tendon, cornea, etc.) are bridged and linked by the anionic glycosaminoglycans (AGAGs) of the small proteoglycans (decoron, etc.). It was proposed that these bridges and ties maintain the collagen fibril dispositions in relation to each other, helping to define tissue shape, and hence called shape modules. This investigation describes chemical and physicochemical conditions in which these structures are stable and what treatments cause their disruption. The effects on fixed and unfixed sections of tendon, cornea, lung and ear from rat, mouse and rabbit of pH, electrolyte concentration, EDTA, mercaptoethanol, hydrogen peroxide, free radicals, periodate, acetylation, urea, nonionic detergent and organic solvents were assessed by staining with Cupromeronic blue or Alcec blue in CEC techniques to localise AGAG bridges or their disintegration products. Ca2+ was not involved in the structures, oxidation/reduction had no effect and Triton X100, a nonionic detergent did not damage them. They were stable between pH 4.5 and 9.5. Periodate as a glycol-cleaving reagent did not affect them. High concentrations of urea (> 2.0 M) and MgCl2 (0.5 M) disrupted the tissues. The combination of Triton and urea at concentrations too low to cause damage separately was disruptive. Free radicals in periodate solutions were damaging. Organic solvents caused collapse and rearrangements of the AGAG filaments. Acetylation caused considerable disruption of shape modules. Dermochondan but not keratan sulphate AGAGs were removed by treatment with NaOH. After fixing with glutaraldehyde only free radical and NaOH treatments were severely disruptive of shape modules. The results are compatible with a previously proposed structure for the shape modules, stabilised by hydrophobic and hydrogen bonding.

The role of calnexin in NK-target cell interaction

In this study, a relationship between target cell sensitivity to natural killing and target cell expression of the molecular chaperone++ calnexin was assessed. The NK-resistant cell line NKR was originally derived from the NK-sensitive, human T-cell line CEM and does not synthesize calnexin protein or mRNA. The cell lines CEM, NKR and 1B9 (NKR transfected with a calnexin cDNA) were compared in a number of assays. All the lines but CEM were resistant to NK in conventional 4 h cytotoxicity assay, but were highly sensitive to IL-2 activated NK. Incubation of NK cells with CEM but not with the other two lines led to increased expression of the NK cell activation marker CD69. Treatment of effector cells with PGE2 and TGF-beta resulted in an inhibition of NK activity and CD69 expression. The calnexin transfected clone 1B9 clone had intermediate ability to block cytotoxicity in cold target inhibition assay compared to CEM and NKR. Expression of the adhesion molecules CD44 and LFA-1alpha was significantly higher on both calnexin positive cell lines compared to NKR. These data suggest that calnexin controls the expression of some, but not all, target structures that are necessary for binding and activation of NK cells.

Postscript on possum cartilage and oxygen; what is keratan sulphate? A corrigendum to the addendum

The recent exchange on cartilage ultrastructure, the localisation of keratan sulphate (KS) therein and the influence of oxygen tension on both (Stockwell & Scott, 1997; Archer et al. 1997; Caterson, 1997) raised important issues which need clarification and extension. We wish to correct certain statements and to examine more rigorously principles which will establish a foundation for future discussion.

Osteogenesis imperfecta mutations may probe vital functional domains (e.g. proteoglycan binding sites) of type 1 collagen fibrils

Osteogenesis imperfecta (OI) is a disease characterized by bone malformations caused by mutations in type 1 collagen. Since many of the 338 possible glycine mutations have not been observed in clinical practice, is this due to chance alone? Because only 83 mutations have been reported in 126 patients, we conclude that many mutations are absent from clinical data for non-random causes. Mutations affecting vital intermolecular interactions in the extracellular matrix (e.g. potential collagen binding sites for proteoglycans) may result in non-viable fetuses that do not progress to clinical status. Some mutations may be silent because they do not significantly affect normal function. The total number of clinically active mutations that will be observed may be far fewer than the potential 338 maximum.

Methylmercury-induced alterations in lung and pulmonary surfactant properties of adult mice

Exposure to methylmercuric chloride (MMC) has been shown to significantly affect development of the lung and pulmonary surfactant system of the fetus. Preliminary results suggest it may also affect adult lung and associated bronchoalveolar lavage (BAL), which represents the extracellular surfactant pool. To determine if mercury exposure has the potential to alter surfactant function, adult mice were treated with MMC, 15 mg/kg by intragastric intubation on 4 successive days. BAL was collected by repeated intratracheal lavage 24 h after the last treatment. Nucleated cell numbers in lavage were determined. Tissue was prepared for scanning electron microscopy (SEM). Lavage fluid was extracted into chloroform:methanol and phospholipid concentration determined. A sample of the extract was used at a constant phospholipid concentration to measure surface activity on a bubble surfactometer. Lung weight to body weight ratio increased whereas total numbers of nucleated cells in BAL were not altered by MMC. SEM of samples from lungs of animals exposed to MMC showed normal architecture. Surface tension measurements suggest that the mean time to minimum surface tension and the minimum surface tension were greater in BAL from mice exposed to MMC for 4 days. In addition samples of BAL were prepared for Fourier-transform infrared spectrophotometry (FT-IR). Spectra showed changes in both lipid and protein components of BAL. Morphometric analyses of micrographs showed that mean alveolar diameter was reduced and wall thickness increased after mercury exposure. These results suggest that methylmercury exposure may significantly affect surface tension characteristics and composition of BAL, possibly through leakage of edematous interstitial tissue.

Screening of newborn babies for familial ureteric reflux

BACKGROUND

Vesicoureteric reflux (VUR) is not usually diagnosed until it is complicated by urinary infection. Prevention probably requires diagnosis in a newborn baby before urinary infection occurs because the peak incidence for infection is in early infancy. VUR is a familial disorder. We sought to find out whether an at-risk group of newborn babies could be identified on the basis of the parents' family history.

METHODS

Over a 3-year period, pregnant women attending the antenatal clinics of three hospitals in the northeast of England were screened for evidence of urinary-tract disease in themselves or their families with a view to eliciting a history of VUR. When a woman, her partner, or a member of either family had a definite (by cystography records) or probable positive history, we recruited the mother to our study. Renal ultrasonography and cystography were done on the newborn babies soon after delivery, and a dimercaptosuccinic acid (DMSA) radioisotope scan at 3 months was done on those with VUR.

FINDINGS

The estimated number of deliveries during the study period was 34,555; 20,891 women were screened; and 211 were recruited and delivered. The index cases were identified from a wide range of family relationships, though over half consisted of mothers and siblings, 19 babies had more than one index case and in 21 families there was one index for more than one baby or a link between families. Cystography was carried out on 186 newborn babies; 38 (20.4%) had VUR. The proportion of newborn babies with VUR among linked index families was 31%. Mothers and siblings amounted to 71% of the index cases for newborn babies with VUR. The difference between confirmed and assumed index cases in VUR prediction was not significant. The female/male sex ratio among index cases was more than 4, but among newborn babies with VUR it was 1.5. Renal ultrasound showed no correlation with VUR, and all DMSA scans but one were normal. No newborn baby developed complications resulting from cystography.

INTERPRETATION

The screening of pregnant women for familial VUR is worthwhile because the frequency of VUR among the newborn babies of those with such a history is significantly higher than in the general population (frequency of VUR 1-2%), particularly if the family history involves more than one member, or more than one generation.

Modification of the Staphylococcus aureus fibronectin binding phenotype by V8 protease

The amount of cell surface fibronectin (Fn)-binding protein (FnBP) adhesin expressed by Staphylococcus aureus is maximal during exponential growth but disappears rapidly as the culture progresses into stationary phase. To identify factors responsible for the loss of cell surface FnBP, a culture of S. aureus L170, which shows high levels of Fn binding, was supplemented at the time of inoculation with concentrated stationary-phase supernatant from S. aureus L530, a strain which binds Fn poorly. The resulting exponential-phase cells were devoid of FnBP. The factor responsible for this activity was purified from the culture supernatant and identified as V8 protease. When cultured with 375 ng of exogenous V8 protease ml(-1), exponential-phase cells of S. aureus L170 were devoid of cell surface FnBP, and concentrations as low as 23 ng x ml(-1) resulted in reduced amounts of FnBP. Addition of the protease inhibitor alpha2-macroglobulin to the culture medium prevented the growth-phase-dependent loss of cell surface FnBP, whereas growth with exogenous V8 protease resulted in reduced adherence to the solid-phase N-terminal fragment of Fn and to the extracellular matrix synthesized by fetal rabbit lung fibroblasts. Although FnBP was extremely sensitive to V8 protease, exogenous protease did not exert a significant influence on the amount of cell surface protein A. However, a limited number of other high-molecular-weight cell surface proteins were also sensitive to V8 protease. Therefore, both the adhesive phenotype and cell surface protein profile of S. aureus can be modified by V8 protease activity.