31P-magnetic resonance spectroscopy and 2H-magnetic resonance imaging studies of a panel of early-generation transplanted murine tumour models

The objective of this study was first to determine whether three slowly growing early-generation murine transplantable tumours, the T40 fibrosarcoma, T115 mammary carcinoma and T237 lung carcinoma, exhibit patterns of energetics and blood flow during growth that are different from those of the faster growing RIF-1 fibrosarcoma. Serial measurements were made with 31P-magnetic resonance spectroscopy (MRS), relating to nutritive blood flow and 2H-magnetic resonance imaging (MRI), which is sensitive to both nutritive and large-vessel (non-nutritive) flow. All four tumour lines showed a decrease in betaNTP/Pi and pH with growth; however, each line showed a different pattern of blood flow that did not correlate with the decrease in energetics. Qualitative histological analysis strongly correlated with the 2H-MRI. Second, their response to 5 mg kg(-1) hydralazine i.v. was monitored by 31P-MRS. A marked decrease in betaNTP/Pi and pH was observed in both the RIF-1 fibrosarcoma and the third-generation T115 mammary carcinoma after hydralazine challenge. In contrast, the fourth generation T40 fibrosarcoma and T237 lung carcinoma showed no change in 31P-MRS parameters. However, a fifth-generation T237 cohort, which grew approximately three times faster than fourth-generation T237 cohorts, exhibited a significant deterioration in betaNTP/Pi and pH in response to hydralazine. These data are consistent with a decoupling between large-vessel and nutritive blood flow and indicate that early-generation transplants that have a slow growth rate and vascular tone are more appropriate models of human tumour vasculature than more rapidly growing, repeatedly transplanted tumours.

The trypanocidal Cape buffalo serum protein is xanthine oxidase

Plasma and serum from Cape buffalo (Syncerus caffer) kill bloodstream stages of all species of African trypanosomes in vitro. The trypanocidal serum component was isolated by sequential chromatography on hydroxylapatite, protein A-G, Mono Q, and Superose 12. The purified trypanocidal protein had a molecular mass of 150 kDa, and activity correlated with the presence of a 146-kDa polypeptide detected upon reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid sequences of three peptide fragments of the 146-kDa reduced polypeptide, ligand affinity and immunoaffinity chromatography of the native protein, and sensitivity to pharmacological inhibitors, identified the trypanocidal material as xanthine oxidase (EC 1.1.3.22). Trypanocidal activity resulted in the inhibition of trypanosome glycolysis and was due to H2O2 produced during catabolism of extracellular xanthine and hypoxanthine by the purine catabolic enzyme.

DT-diaphorase and cytochrome B5 reductase in human lung and breast tumours

The level of expression of enzymes that can activate or detoxify bioreductive agents within tumours has emerged as an important feature in the development of these anti-tumour compounds. The levels of two such reductase enzymes have been determined in 19 human non-small-cell lung tumours and 20 human breast tumours, together with the corresponding normal tissue. DT-diaphorase (DTD) enzyme levels (both expression and activity) were determined in these samples. Cytochrome b5 reductase (Cytb5R) activity was also assessed. With the exception of six patients, the levels of DTD activity were below 45 nmol min(-1) mg(-1) in the normal tissues assayed. DTD tumour activity was extremely variable, distinguishing two different groups of patients, one with DTD activity above 79 nmol min(-1) mg(-1) and the other with levels that were in the same range as found for the normal tissues. In 53% of the lung tumour samples, DTD activity was increased with respect to the normal tissue by a factor of 2.4-90.3 (range 79-965 nmol min[-1] mg[-1]). In 70% of the breast tumour samples, DTD activity was over 80 nmol min(-1) mg(-1) (range 83-267 nmol min[-1] mg[-1]). DTD expression measured by Western blot correlated well with the enzyme activity measured in both tumour and normal tissues. The levels of the other reductase enzyme, Cytb5R, were not as variable as those for DTD, being in the same range in both tumour and normal tissue or slightly higher in the normal tissues. The heterogeneous nature of DTD activity and expression reinforces the need to measure enzyme levels in individual patients before therapy with DTD-activated bioreductive drugs.

Strontium increases vertebral bone volume in rats at a low dose that does not induce detectable mineralization defect

Low doses of strontium and fluoride were shown to increase bone formation and trabecular bone density in rodents. To assess whether strontium or fluoride affect the quality of the mineral at doses known to increase bone density, we have determined the effects of low doses of strontium and fluoride on bone formation and bone mineral characteristics in rats. Adult rats were given strontium alone (0.20%), fluoride alone (1 mg/kg per day), or the combined treatment for 8 weeks. Strontium levels in serum and femur were similar in groups treated with strontium alone or in combination, being about 5% of calcium levels. Biochemical and neutron activation analyses in femur showed that calcium and magnesium contents did not differ in the four group of rats, suggesting that strontium was incorporated in the apatite lattice of the bone minerals in the strontium-treated rats. The mineralized bone volume was significantly increased by 17% in the strontium-treated group, by 20% in the fluoride-treated group, and by 19% in rats given with the combined treatment. This was associated with increased osteoid surface, osteoblast surface, and double tetracycline labeled surfaces in the strontium-treated and fluoride-treated groups, showing that the number of bone forming sites was increased. However, the mineral apposition rate, the osteoid thickness, and the mineralization lag time were similar in controls and treated groups, reflecting the lack of deleterious effects of low doses of strontium and fluoride on bone mineralization. The density fractionation analysis measured in the femur also showed that neither strontium, nor fluoride at the low doses used, significantly altered the mineralization profile. The results indicate that treatment with low doses of strontium or fluoride increase the number of bone forming sites and vertebral bone volume in rats, but does not have detectable adverse effects on the mineral profile, bone mineral chemistry or bone matrix mineralization.

Hypoxia-selective agents derived from 2-quinoxalinecarbonitrile 1,4-di-N-oxides. 2

Hypoxic cells are an important target for antitumor therapy because tumors are typically characterized by such cells. Virtually all tumors which are present as solid masses contain hypoxic cells, while normal cells generally have an adequate supply of oxygen. Accordingly, antitumor agents can be made selective for tumors by virtue of high activity under hypoxic conditions. The initial purpose of this work was to determine the influence of different groups in position 3. Thus, the synthesis of some 3-NH-substituted derivatives (2a, 3a, 4a) starting from 3-amino-2-quinoxalinecarbonitrile 1,4-di-N-oxide (1a) is described. Reductive deamination of compounds 1a-k provides the 2-quinoxalinecarbonitriles 5a-k, which are more potent, while selectivity is maintained or increased in some derivatives. The compound 7-(4-nitrophenyl)-2-quinoxalinecarbonitrile 1,4-di-N-oxide (5k) is 150-fold more potent than tirapazamine (3-amino-1,2,4- benzotriazine 1,4-di-N-oxide), which has been used as a standard. Three derivatives (5g,i,k) show a hypoxic cytotoxicity ratio (HCR) > or = 200, better than that of tirapazamine (HCR = 75) in V79 cells. Replacement of the 3-amino group by chlorine affords the potent but nonselective 3-chloro derivatives 6a-k showing similar toxicities under both aerobic and hypoxic conditions. These compounds were used as intermediates for the synthesis of a new series of water-soluble compounds derived from 3-[[(N,N- dialkylamino)alkyl[amino]-2-quinoxalinecarbonitrile 1,4-di-N-oxides 10a-i and 11a-i. The 7-chloro and the 7-trifluoromethyl derivatives 10b,f have demonstrated high potency (0.4 and 0.3 microM) and excellent selectivity (HCR = 250 and 340). Several 7-chloro analogues, 12b, 13b.1,b.2, and 14b, and the dimer 16b have been prepared and evaluated in order to determine the optimum lateral chain in position 3, which appears to be the [(N,N-dimethylamino)propyl]amino moiety.

Modification of tumour glucose metabolism for therapeutic benefit

Tumours have a much greater dependence than normal tissues on anaerobic glycolysis for energy generation. We have studied the effects of glycolysis inhibition on tumour cells in vitro. Cellular ATP fell during exposure of cells in air to 2-deoxy glucose or to the lactate dehydrogenase inhibitor oxamate. Glycolysis inhibition alone did not alter clonogenic cell survival over 6 h, but a 6-h exposure to oxamate combined with doxorubicin (Dox) gave greater than additive cell killing. This effect was greatest when oxamate was dosed after Dox, suggesting that oxamate inhibited repair of Dox-induced damage. Oxamate also gave greater than additive cell killing in multicellular spheroids when combined with Dox and there was a greater than additive growth delay in spheroids dosed with Dox plus oxamate. These data demonstrate that inhibition of anaerobic glycolysis might be used to obtain a significant therapeutic gain in combination treatments with cytotoxic drugs or radiotherapy.

Perinatal research and its support. Corporate contributions at McGill University

Three technologic projects with potentially patentable end results are slowly evolving in the Department of Obstetrics and Gynecology, McGill University and Royal Victoria Hospital. A tax shelter infusion of a significant amount of venture capital developed opportunities for all three projects over two years. The three projects--fetal heart rate tracing analysis related to fetal outcome, a distributed and intelligent data acquisition system and selected ultrasonic three dimensional imaging--were advanced considerably, and their results are expressed in outline. The effects of such infusions of business support into an environment of sparse research grant support have been extremely encouraging to the investigators, but the department, with its obligations of ongoing research, teaching and patient care, must develop the next steps with care, although one of the projects has been extended by an interested corporation.

Hepatic hypertrophic osteoarthropathy and liver transplantation

OBJECTIVES

To document the variety of liver diseases and the clinical picture of hepatic hypertrophic osteoarthropathy (HOA) complicated by arthritis and to report the effects of successful liver transplantation on this disabling condition.

METHODS

Seven patients with severe liver disease (two biliary atresia, two primary sclerosing cholangitis, one Wilson's disease, one primary biliary cirrhosis (PBC) and one alcoholic cirrhosis) complicated by radiologically proven hepatic HOA and suffering from arthritis are described.

RESULTS

In four of the six patients who required hepatic transplantation for inadequate liver function successful grafting was achieved with complete clinical remission of the painful arthritis. This occurred three days to 18 months later.

CONCLUSIONS

Hepatic HOA with arthritis occurs in a variety of liver diseases. Despite resistance of this arthritis to conventional therapies, successful liver transplantation was associated with complete clinical remission in four of the cases reported.

Association of radiographic changes of osteoarthritis, symptoms, and synovial fluid particles in 300 knees

Associations between compartmental distribution of radiographic changes of osteoarthritis (OA), individual features of OA (joint space loss, sclerosis, cyst, osteophyte; each scored 0-3), and presence of synovial fluid calcium particles (calcium pyrophosphate dihydrate (CPPD) crystals identified by polarised light microscopy and other calcium particles by alizarin red positivity (ARP) were sought in 300 osteoarthritic knees (178 patients; mean age 72, range 33-96 years). Patients whose knees were symptom free as well as those with symptoms were included. Osteoarthritis of two or three compartments but not unicompartmental OA was associated with the presence of CPPD or ARP. Involvement of any compartment (not just patellofemoral), and higher mean scores for both total and individual osteoarthritis changes (except cysts) was associated with CPPD and ARP; CPPD, but not ARP, was associated with symptoms: knees reported as having symptoms had higher mean total OA scores. Femoral cortical erosion, found more often in women, was associated with higher mean total OA score at the patellofemoral compartment but not with the presence of particles. Attrition, remodelling, and chondrocalcinosis (each scored as present or absent) occurred more often in knees with CPPD. Age did not correlate with any aspect of the OA score. This study confirms the association of calcium particles with the process of OA. Unlike previous studies confined to symptomatic knees, a radiographic pattern specific to CPPD ('pyrophosphate arthropathy') did not emerge.

Articular manifestations of Scheie's syndrome

A patient with the clinical and biochemical features of Scheie's syndrome is reported. Radiological investigation has shown severe progressive juxta-articular cystic lesions, which have not, to our knowledge, previously been described in Scheie's syndrome.

Inorganic pyrophosphate in metabolic diseases predisposing to calcium pyrophosphate dihydrate crystal deposition

Inorganic pyrophosphate (PPi) levels were estimated by radiometric assay in urine and in synovial fluid (SF) from asymptomatic, nonarthritic knees of patients with untreated metabolic disease and normal controls. SF PPi was significantly elevated in patients with hyperparathyroidism (mean +/- SEM 19 +/- 3 microM; n = 9), hemochromatosis (23 +/- 5 microM; n = 6), and hypomagnesemia (27 +/- 0.1 microM; n = 2) compared with normal subjects (10 +/- 0.5 microM, n = 50), and was low in patients with hypothyroidism (4.2 +/- 2.3 microM; n = 11) (P less than 0.05 all comparisons). Urinary PPi was elevated only in those with hypophosphatasia. Local elevation of ionic PPi may be relevant to the mechanism of crystal formation in metabolic diseases predisposing to calcium pyrophosphate dihydrate (CPPD) crystal deposition. The finding of low SF PPi levels in patients with hypothyroidism further questions the association between this condition and CPPD.

Inorganic pyrophosphate, nucleoside triphosphate pyrophosphatase, and cartilage fragments in normal human synovial fluid

The association between calcium pyrophosphate dihydrate (CPPD) crystal deposition and ageing is unexplained. Levels of inorganic pyrophosphate (PPi) and activity of nucleoside triphosphate pyrophosphatase (NTPP) were estimated in synovial fluid from 91 asymptomatic normal knees, including five with isolated CPPD crystal deposition (70 subjects; median age 47, range 22-83 years). In non-crystal fluids, PPi levels and NTPP activities were low (median, interquartile range: 9.5, 7.6-12.3 microM, and 1, 0.4-2 microM/30 min/mg protein, respectively: n = 50) and a generalized increase with age was not demonstrated. Higher values for PPi and NTPP in all five subjects with isolated CPPD deposition supports involvement of altered PPi metabolism, unrelated to ageing per se, in crystal formation. Presumed cartilage fragments were identified by morphological characteristics in 70% of normal fluids: metachromatic staining and electron microscopy, undertaken in a limited number, supported identification of such particles as cartilage. This finding supports dynamic turnover of healthy matrix, and questions the usefulness of identification, without quantification, cartilage fragments as a measure of cartilage damage.

Synovial fluid pyrophosphate and nucleoside triphosphate pyrophosphatase: comparison between normal and diseased and between inflamed and non-inflamed joints

Deposition of intra-articular calcium pyrophosphate is associated with both aging and arthropathy; increased concentrations of free pyrophosphate (PPi) may contribute to such deposition. Free pyrophosphate and nucleoside triphosphate pyrophosphatase (NTPase) were estimated in synovial fluids from 50 subjects with normal knees and from 44 patients with rheumatoid arthritis, 61 with pyrophosphate arthropathy, and 59 with osteoarthritis. For arthropathic knees clinically assessed inflammation was classified as active or inactive using a summated score of six clinical features. The order of PPi (mumol/l) and NTPase (mumol PPi/30 min/mg protein) was pyrophosphate arthropathy greater than osteoarthritis greater than rheumatoid arthritis (median PPi, NTPase respectively: for pyrophosphate arthropathy 15.9, 0.45; for osteoarthritis 9.3, 0.25; for rheumatoid arthritis 4.4, 0.18), with significant differences between all groups. In pyrophosphate arthropathy both PPi (mumol/l) and NTPase (mumol PPi/30 min/mg protein) were higher than normal (15.9, 0.45 v 8.6, 0.2 respectively), but findings in osteoarthritis did not differ from normal. The inflammatory state of the knee had a distinct but variable effect on synovial fluid findings in rheumatoid arthritis and pyrophosphate arthropathy, but not in osteoarthritis. There was no correlation of either PPi or NTPase with age, or between PPi and NTPase in any group. This study provides in vivo data for synovial fluid PPi and NTPase. It suggests that factors other than PPi need to be considered in a study of crystal associated arthropathy. Clinical inflammation, as well as diagnosis, is important in synovial fluid studies.

Familial chondrocalcinosis due to calcium pyrophosphate dihydrate crystal deposition in English families

Familial predisposition to chondrocalcinosis (CC) due to calcium pyrophosphate dihydrate (CPPD) crystal deposition is described in five English kindreds. Two families were characterized by premature-onset polyarticular CC with little associated structural arthropathy. In one of these families, recurrent childhood fits were strongly associated with subsequent development of CC. Affected members of the other three families resembled sporadic disease in showing predominantly late-onset, oligoarticular CC with mild arthritis and destructive change in only one case. Knee synovial fluid levels of inorganic pyrophosphate (PPi) and nucleoside triphosphate pyrophosphate (NTPP) did not differ from those of 59 sporadic cases of CC due to CPPD, although PPi and NTPP levels in both groups were higher than in normal knee synovial fluid (P less than 0.0001). Urinary PPi levels were not different from normal controls. Screening for other metabolic abnormality was negative in all cases. This is the first report of familial CC in the UK, and the first to associate this condition with childhood fits. Absence of overt primary abnormality of PPi metabolism suggests that other factors relating to crystal nucleation/growth may be more relevant to predisposition in these cases.

Synovial fluid calcium pyrophosphate dihydrate crystals and alizarin red positivity: analysis of 3000 samples

Three thousand synovial fluids (1312 patients: chronic pyrophosphate arthropathy (CPA), 41%; osteoarthritis (OA), 12%; rheumatoid arthritis (RA), 16%) were examined for crystals, including calcium pyrophosphate dihydrate (CPPD), by polarized microscopy (score 0-3); calcific particles, by alizarin red positivity (ARP; 0-3); and total cell count. For 1150 fluids, local joint inflammation was assessed as 'active' or 'inactive' using a summated score of six clinical variables. CPPD and ARP scores did not correlate, but each showed positive correlation with age (P less than 0.01, P less than 0.02 respectively). Pseudogout had the highest mean CPPD score (P less than 0.001); intermittent CPPD positivity (range 8-100%) was seen in serially aspirated CPA joints, and there was no difference in CPPD positivity or score between active and inactive CPA. ARP was most frequent in OA subsets (72% of CPA, 46% of OA, 31% of RA; P less than 0.001). ARP was more frequent in active than inactive OA (P less than 0.05) but showed no association with inflammation in CPA or RA. Cell counts were higher in RA and pseudogout compared to OA and CPA, and in active compared to inactive RA. No correlation was found between ARP or CPPD scores and cell count. Cholesterol crystals were uncommon (0.2%) and showed no disease or joint predilection. In arthritic joints, CPPD and calcific particles particularly associate with the OA process and ageing. CPPD may contribute to acute and other calcific particles to chronic inflammation in OA.

A controlled study of hand function in nodal and erosive osteoarthritis

Hand function using a standardised test of activities of daily living was assessed in (a) 57 patients (53 female, four male; mean age 69 years) with established (that is, symptom onset greater than 10 years before) nodal generalised osteoarthritis (NGOA); (b) 10 patients (nine female, one male; mean age 70 years) with established erosive osteoarthritis (EOA); and (c) 52 matched controls (48 female, four male; mean age 71 years) with asymptomatic, clinically normal hands. Although significant differences between controls and patient groups were observed for individual tasks, only minor global impairment was seen, the worst function occurring in patients with EOA. There was no consistent correlation between tested aspects of hand function and extent of radiographic change assessed by summated graded score for separate osteoarthritic features in individual joints. In controls increasing age correlated with longer time to complete all tasks and weaker power grip; a similar, less pronounced correlation occurred in patients. Differences between controls and patients with NGOA were most apparent in younger subjects; in the elderly (greater than 80 years) hand function was essentially the same. This study shows good functional outcome for patients with NGOA, and suggests that the OA process is of little functional importance to the aging hand.