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.

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 adaptive significance of mandibular symphyseal fusion in mammals.

The mandibular symphyseal joint is remarkably variable across major mammalian clades, ranging in adults from unfused (amphiarthrosis) to partially fused (synarthrosis) to completely ossified (synostosis). Experimental work conducted on primates suggests that greater ossification of the symphysis is a response to increased recruitment of the balancing-side (i.e. nonchewing side) jaw-adductor muscles during forceful unilateral biting and chewing, with increased fusion strengthening the symphysis against correspondingly elevated joint stresses. It is thus expected that species with diets composed primarily of foods that require high-magnitude bite forces and/or repetitive loading to process will be characterized by greater degrees of symphyseal ossification than species with relatively easy-to-process diets (i.e. food items typified by low toughness and/or low stiffness). However, comparative support for this idea is limited. We tested this hypothesis in four dietarily diverse mammalian clades characterized by variation in symphyseal fusion - the Strepsirrhini, Marsupialia, Feliformia, and Caniformia. We scored fusion in adult specimens of 292 species, assigned each to a dietary category based on literature accounts, and tested for an association between these two variables using Pagel's test for the correlated evolution of binary characters. Results indicate that greater fusion is associated with diets composed of resistant items in strepsirrhines, marsupials, and feliforms, providing some support for the hypothesis. However, no such relationship was detected in caniforms, suggesting that factors other than dietary mechanical properties influence symphyseal ossification. Future work should focus on such factors, as well as those that favour an unfused mandibular symphysis.

Further studies on metachromasia in cultured human fibroblasts. Staining of glycosaminoglycans (mucopolysaccharides) by Alcian blue in salt solutions.

Staining with Alcian blue in various concentrations of magnesium chloride (alcianophilia) has been found to be a useful supplement to metachromatic staining to detect increased cellular concentrations of glycosaminoglycans (mucopolysaccharides). In many instances alcianophilia at 0.3 M MgCl(2) is more specific than metachromasia and does not give "false positives" sometimes found in normal individuals and in those with cystic fibrosis, Gaucher's disease, familial amaurotic idiocy, and pseudoxanthoma elasticum. On the other hand, it gives a "false negative" reaction in the Sanfilippo syndrome (perhaps because the characteristically elevated glycosaminoglycan in this disease, heparan sulfate, is not synthesized by cultured skin fibroblasts), and in the Marfan syndrome. It detects the Maroteaux-Lamy syndrome, which metachromasia does not. The "false positives" given by metachromasia in all six families studied thus far are genuine, reproducible reactions that can be traced through at least three generations of normal individuals within a family. There is therefore, in these families, a genetic factor that causes such metachromasia, but it is not increased glycosaminoglycan concentration.

Oxygen and the connective tissues.

Avascular connective tissues (cartilage, discs, cornea) change with maturation and aging, particularly in large animals, where diffusion paths are longest. It is suggested that the changes in such tissues are responses to increasing difficulties in obtaining oxygen. Two almost identical structural polymers are made in these tissues: chondroitin sulphate, which requires large amounts of oxygen for biosynthesis and keratan sulphate, which requires relatively little. The observed balance of these polymers in the tissue is proposed to depend on the control of biosynthesis by the ambient oxygen tension, and/or selective breakdown.

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.

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.

Postoperative cognitive dysfunction and its relationship to cognitive reserve in elderly total joint replacement patients.

Whether total joint replacement (TJR) patients are susceptible to postoperative cognitive dysfunction (POCD) remains unclear due to inconsistencies in research methodologies. Moreover, cognitive reserve may moderate the development of POCD after TJR, but has not been investigated in this context. The current study investigated POCD after TJR, and its relationship with cognitive reserve, using a more rigorous methodology than has previously been utilized. Fifty-three older adults (aged 50+) scheduled for TJR were assessed pre and post surgery (6 months). Forty-five healthy controls matched for age, gender, and premorbid IQ were re-assessed after an equivalent interval. Cognition, cognitive reserve, and physical and mental health were all measured. Standardized regression-based methods were used to assess cognitive changes, while controlling for the confounding effect of repeated cognitive testing. TJR patients only demonstrated a significant decline in Trail Making Test Part B (TMT B) performance, compared to controls. Cognitive reserve only predicted change in TMT B scores among a subset of TJR patients. Specifically, patients who showed the most improvement pre to post surgery had significantly higher reserve than those who showed the greatest decline. The current study provides limited evidence of POCD after TJR when examined using a rigorous methodology, which controlled for practice effects. Cognitive reserve only predicted performance within a subset of the TJR sample. However, the role of reserve in more cognitively compromised patients remains to be determined.

Influence of protein kinase C activation by 4 beta-phorbol ester or 1-oleoyl-2-acetylglycerol on disaturated phosphatidylcholine synthesis and secretion, and protein phosphorylation in differentiating fetal rabbit type II alveolar cells.

Undifferentiated type II alveolar cells were isolated from the fetal rabbit lung on the 24th gestational day, grown in vitro for 2-3 days, and used to test the hypothesis that activation of protein kinase C by 4 beta-phorbol ester (TPA) or the diacylglycerol analogue, sn-1-oleoyl-2-acetylglycerol (OAG), stimulates disaturated phosphatidylcholine (DSPC) synthesis and secretion. To measure secretion, cells were prelabelled with [3H]choline in serum-free medium or medium with 10% carbon-stripped fetal bovine serum for 24 h. The radiolabel was removed and TPA (10(-6)-10(-9) M) or OAG (125, 250 or 500 microM) was incubated with the cells for 2 h. The medium was removed and filtered. Fresh medium with the same compound was added for an additional 16 h. To measure synthesis, cells were incubated with [3H]choline and concurrently TPA or OAG was added. Cells were removed at 2 or 18 h. After 2 h at concentrations of 10(-8) M, TPA augmented the release of 3H-labelled DSPC, the major component of the surfactant, by cells incubated in serum-free medium. In the presence of carbon-stripped fetal bovine serum, TPA (10(-7) and 10(-6) M) induced release of DSPC. The incorporation of [3H]choline into intracellular DSPC was increased after 2 or 18 h in fetal alveolar cells exposed to TPA at 10(-9) M or higher. OAG also significantly significantly stimulated the release of labelled DSPC after 2 h at all concentrations tested. In contrast, OAG-exposed cells displayed a reduction of [3H]choline incorporation into cellular DSPC. Characterization of radioactive material released by prelabelled fetal type II cells showed that phorbol ester stimulation increased the release of material which co-migrated with adult rabbit lung lamellar bodies on a sucrose gradient. Electrophoretic examination of [gamma-32P]ATP phosphorylation sites in fetal type II cells cells showed that TPA and OAG induced an increase in phosphorylation of a group of proteins with apparent molecular masses of 45, 50 and 55 kDa. Addition of phosphatidylserine to the incubations produced substantial increase in the phosphorylation of these proteins, particularly in the presence of TPA. Fetal type II cells also displayed a phosphorylation product with an apparent molecular mass of 97 kDa. This protein as well as two high-molecular-mass products appeared to be particular to cells incubated with TPA plus phosphatidylserine and may in part account for the different action of TPA compared to OAG with regard to synthesis and secretion of DSPC by the fetal type II cells.

Alveolar pre-type II cells from the fetal rabbit lung. Isolation and characterization.

A method for preparing a homogeneous population of undifferentiated cells from the fetal rabbit lung is described. This method utilizes enzymatic digestion, differential adhesion to remove fibroblasts and centrifugation on a discontinuous metrizamide gradient. Cells isolated by this procedure replicate in vitro in medium supplemented with carbon-stripped fetal bovine serum. Mitosis can also be stimulated by heat-inactivated medium conditioned by fetal lung fibroblasts. After confluence, exposure of these cells to 0.55 or 55 nM dexamethasone significantly increased the incorporation of [14C]choline into phosphatidylcholine. Lower concentrations of the drug also increased incorporation, but not significantly so. Addition of heat-inactivated fibroblast-conditioned medium produced a 25% increase in choline incorporation, but this was not significant. Furthermore, the presence of conditioned medium tended to reduced the response of the cells to dexamethasone. After confluence, lamellar inclusion bodies were present in more than 90% of those cells exposed to dexamethasone. These organelles were not observed in cell monolayers not exposed to the steroid. These cells did contain a few small electron-dense bodies. The latter may be immature multivesicular bodies.

Alveolar pre-type II cells from the fetal rabbit lung: effect of confluence on the production of disaturated phosphatidylcholine.

Pre-type II alveolar cells isolated from the fetal rabbit lung on the 24th gestational day have been maintained in vitro for 14 days in a chemically defined medium supplemented with hormone-stripped serum. These cells replicate in culture. Measurement of the incorporation of [14C]choline into cellular disaturated phospholipid indicated that those cells grown in vitro under standard conditions for 8 days (pre-confluent) incorporate the radioactive precursor at a similar rate to cells maintained for 14 days (post-confluent). Both dexamethasone and serum-free medium conditioned by monolayer cultures of fetal rabbit lung fibroblasts stimulated [14C]choline incorporation into disaturated phosphatidylcholine (PC) by the pre- and post-confluent cultures after 24 or 48 h of exposure: the conditioned medium was more effective than the steroid. These treatments had little effect on choline incorporation into disaturated phosphatidylcholine of preconfluent cells during the first 12 h. A marked response occurred by 24 h after which the labelling of disaturated phosphatidylcholine plateaued. In contrast, with post-confluent cells labelling of disaturated PC increased in a more linear fashion and only plateaued after 72 h. Determination of the ratio of incorporation of [14C]choline into disaturated versus unsaturated phospholipid indicated that serum-free medium conditioned by monolayer cultures of fetal lung fibroblasts specifically increased the level of radioactive precursor in the disaturated phospholipid in both the pre- and post-confluent cell monolayers.

Profile of phospholipase A2 activity in subcellular fractions and lamellar bodies of developing, neonatal and adult rabbit lung. Correlation with intracellular levels of disaturated phosphatidylcholine.

Phospholipase A2 activity was determined in subcellular fractions and lamellar bodies of fetal, neonatal and adult rabbit lungs. Specific activity in most fractions decreased from the 24th to the 28th day of gestation. All fractions except the mitochondrial and the nuclear fractions exhibited a sharp increase in activity in the newborn lung. Specific activity in the adult lung generally declined in comparison to neonatal values. During gestation total enzyme activity per gram of lung was concentrated in the cytosolic fraction. With the exception of the lamellar body fraction, the total content of phospholipase A2 activity increased dramatically in all fractions from the neonatal lung. The lamellar body fractions displayed both low specific activity and low total enzyme activity during gestation. Specific activity increased dramatically in the neonatal and adult lung but still accounted for only a small fraction of the activity in comparison to the other subcellular fractions. The subcellular content of disaturated phosphatidylcholine (PC) appeared to correlate well with the activity of phospholipase A2 in the neonatal mitochondrial, microsomal and cytosolic fractions. Since decreasing prenatal enzyme levels are associated with increasing disaturated PC content, the alkaline and calcium-dependent phospholipase A2 may not be directly involved in disaturated PC synthesis in the fetus. However, postnatally, the correlation between the pattern of production of disaturated PC and the activity of the phospholipase A2 indicates a role for this enzyme in surfactant-related disaturated PC synthesis.

Effect of oxygen tension and lactate concentration on keratan sulphate and chondroitin sulphate biosynthesis in bovine cornea.

Calf cornea slices were incubated with [U-14C]glucose, in varying pO2 or lactate concentrations. Acid glycosaminoglycans were separated by ion-exchange chromatography after papain digestion. The percentage radioactivity incorporated into keratan sulphate increased markedly with decreased oxygen tension, whereas a concomitant relative decrease of the biosynthesis of glycosaminoglycuronans occurred. Similar results were obtained with increased lactate concentration. Our findings support the idea that keratan sulphate is a functional substitute for chondroitin sulphate in conditions of oxygen lack (Scott, J.E. and Haigh, M. (1988) J. Anat. 158, 95-108).

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.

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.

Stimulation of signal transduction pathways in osteoblasts by mechanical strain potentiated by parathyroid hormone.

Second-messenger systems have been implicated to transmit mechanical stimulation into cellular signals; however, there is no information on how mechanical stimulation is affected by such systemic factors as parathyroid hormone (PTH). Regulation of adenylyl cyclase and phosphatidylinositol pathways in rat dentoalveolar bone cells by mechanical strain and PTH was investigated. Two different cell populations were isolated after sequential enzyme digestions from dentoalveolar bone (group I and group II) to study potential differences in response. Mechanical strain was applied with 20 kPa of vacuum intermittently at 0.05 Hz for periods of 0.5, 1, 5, 10, and 30 minutes and 1, 3, and 7 days using the Flexercell system. Levels of cAMP, measured by RIA, and levels of inositol 1,4,5-triphosphate (IP3) and protein kinase C activity (PKC), measured by assay systems, increased with mechanical strain. When PTH was added to the cells, there was a significant increase in levels of all the intracellular signals, which appeared to potentiate the response to mechanical strain. IP3 levels (0.5 minute) peaked before those of PKC activity (5 minutes), which in turn peaked before those of cAMP (10 minutes). Group II cells showed higher levels of cAMP and IP3 than the group I cells. This suggests that the former may ultimately play the predominant roles in skeletal remodeling in response to strain. Immunolocalization of the cytoskeleton proteins vimentin and alpha-actinin, focal contact protein vinculin, and PKC showed a marked difference between strained and nonstrained cells. However, the addition of PTH did not cause any significant effect in cytoskeleton reorganization. Staining of PKC and vimentin, alpha-actinin, and vinculin suggests that PKC participates actively in the transduction of mechanical signals to the cell through focal adhesions and the cytoskeleton, although only PKC seemed to change with short time periods of strain. In conclusion, dentoalveolar osteoblasts responded to mechanical strain initially through increases in levels of IP3, PKC activity, and later cAMP, and this response was potentiated when PTH was applied together with mechanical strain.

A passive agglutination method using collagen-coated tanned sheep erythrocytes to demonstrate collagen-glycosaminoglycan interaction.

A haemagglutination method originally designed to detect and measure antibody has been shown to be capable of monitoring interactions of glycosaminoglycans and collagen in vitro under physiological conditions of pH and ionic strength. In this system, dermatan sulphate and chondroitin 4-sulphate interact at higher dilutions ('higher titres') with collagen than do chondroitin 6-sulphate or keratan sulphate. The results are relevant to studies of anti-collagen antibodies in connective tissue fluids and extracts, as well as to connective tissue physiology.

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.

An 'affinity' method for preparing polypeptides enriched in the collagen-associated Ehrlich chromogen.

The collagen-associated compound which reacts at room temperature with acid dimethylaminobenzaldehyde (Ehrlichs reagent) also reacts in acid with aryl-diazonium reagents. We have developed a convenient method for isolating polypeptides associated with the Ehrlich chromogen from collagen digests utilizing diazotized arylamino-cellulose supports. These peptides, in which the Ehrlich chromogen is 'labeled' with yellow diazo color, constitute less than 0.5% of the collagen, and have amino acid patterns similar to those around the cross link regions. The chromogen is not identical with pyridinoline, also thought to be a polyvalent cross link.

The chemical morphology of extracellular matrix in experimental rat liver fibrosis resembles that of normal developing connective tissue.

The time course of development of extracellular matrix (ECM) in experimentally induced fibrosis (thioacetamide administration followed for 12 weeks or bile duct ligation for 8 weeks) in adult rats was examined by light and electron microscopy, using Alcian blue or Cupromeronic blue staining for sulphated proteoglycans (PGs) in critical electrolyte concentration techniques. Proteodermatan sulphate (PDS) was regularly observed at the gap zone of the collagen fibrils. Morphometry of uranyl acetate-stained collagen fibrils, polarity of their banding patterns (a-e), statistics of d/e band occupancies by PDS, and lengths and thicknesses of PG filaments were quantified. Biochemical analyses showed that the ECM components collagen, hyaluronan, chondroitin and dermatan sulphates increased by 5-10 fold, roughly in parallel, as did heparan sulphate and DNA. Water and lipid contents also increased sharply. Thioacetamide treatment was much slower than bile duct ligation in producing fibrotic changes of equal severity. Sulphation of anionic glycosaminoglycans (AGAGs) decreased with increasing severity of fibrosis. Biochemical and ultrastructural methods correlated well. The large increase in dermatan sulphate was quantitatively as expected, given that it is collagen fibril surface-associated, and there was an increase of collagen content together with a decrease in fibril thicknesses. The increase in DNA reflected the marked increase in cell numbers in fibrotic livers. The chemical morphology of the new connective tissue closely resembled that in e.g. developing young tendon, in that fibrils were thinner, and AGAG levels were higher. The collagen fibrils were often disarranged, rather than ordered and parallel as in normal ECM. No other indication of abnormality in the new ECM was obtained.