Biomedical subjects
Publications and source records attributed to L M Ryan.
We describe a 33-year-old woman with acute calcific periarthritis (ACP) of the interphalangeal joint of the thumb and review 42 reported cases of ACP involving the finger joints. A computer assisted literature search for reported cases of ACP involving the finger joints was performed. Clinical features of our case and those fulfilling the criteria for entry into this study were analyzed.
OBJECTIVE: To identify the morphology of a mineral-forming of adult porcine hyaline articular cartilage digest and characterize the mineral it forms. METHODS: Electron microscopy, Fourier transform infrared (FTIR) spectroscopy, x-ray microanalysis, compensated polarized light microscopy, and biochemical studies including 14C-labeled UDPG pyrophosphohydrolase radiometric assay. RESULTS: This fraction of articular cartilage digest contained membrane-limited vesicles resembling growth plate cartilage matrix vesicles and formed mineral after only 24 hours in physiologic salt solution containing 1 mM ATP: The mineral contained inorganic pyrophosphate, 95% of which derived from ATP, and phosphate, 93% of which derived from inorganic phosphate in the medium. The FTIR spectrum of this mineral closely resembled the spectrum of standard calcium pyrophosphate dihydrate (CPPD) crystals. Compensated polarized light microscopy showed positively birefringent, rod-shaped crystals morphologically identical to CPPD. Ca:P ratios, defined by energy-dispersive microanalysis, were also consistent with CPPD. CONCLUSION: The articular cartilage vesicle fraction of porcine hyaline cartilage is capable of generating mineral that strongly resembles CPPD.
OBJECTIVE: To determine whether adult articular cartilage mineralizes in the presence of ATP. METHODS: Intact adult porcine articular cartilage and monolayers of chondrocytes were cultured in physiologic media containing ATP, and mineralization was measured as retention of 45Ca. Cartilage was analyzed by electron microscopy. RESULTS: Articular cartilage sequestered 45Ca when incubated with 100 microM ATP: Use of the ATP analog alpha, beta-methylene ATP did not promote mineralization and addition of pyrophosphatase inhibited mineralization, indicating that hydrolysis of ATP to AMP and inorganic pyrophosphate is necessary for the process to occur. Mineral was concentrated in articular cartilage vesicles in the perichondral area. CONCLUSION: Adult articular cartilage mineralizes in the presence of ATP, in a manner similar to that found with isolated matrix or articular cartilage vesicles. This supports the notion that these structures have a role in chondrocalcinosis.
EST 2287 was a Phase II clinical trial conducted by the Eastern Cooperative Oncology Group (ECOG) designed to evaluate trimetrexate in patients with advanced, measurable, inoperable squamous cell carcinoma of the esophagus. The drug was given at a dose of 12 mg/m2 daily for 5 days every 21 days to patients with carcinoma of the esophagus. The purpose of this study was to evaluate treatment efficacy in terms of tumor response and to assess the toxicity. According to a two-stage stopping rule, the study closed after 15 patients had entered. There were no responses to treatment, and median survival from study entry was 4.3 months. There was one treatment-related death caused by infection. One patient experienced life-threatening hematologic toxicity. Overall severe or worse toxicity occurred in more than half of the patients. It is concluded that additional trials of trimetrexate at this dose and schedule in patients with carcinoma of the esophagus are not warranted.
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The overproduction of inorganic pyrophosphate (PPi) by cartilage is thought to be a key element in the formation of calcium pyrophosphate dihydrate (CPPD) crystals in joints, and the subsequent development of pseudogout or chondrocalcinosis. We report herein that transforming growth factor beta 1 (TGF beta 1), alone and in synergy with epidermal growth factor (EGF) or TGF alpha, markedly stimulates PPi elaboration by porcine articular cartilage in organ culture and monolayer culture. This effect is not seen with platelet-derived growth factor, basic fibroblast growth factor, or insulin-like growth factor types 1 and 2, substances which also affect chondrocyte metabolism or are mitogenic. TGF beta 1 produces only a modest increase in nucleoside triphosphate pyrophosphohydrolase (NTPPPH), a chondrocyte ectoenzyme that produces PPi; this implies the existence of other pathways for PPi elaboration. TGF beta 1 is present in joint fluid and cartilage. TGF beta 1, TGF alpha, and EGF are the first known physiologic modifiers of cartilage PPi production. They provide a novel model for the study of CPPD crystal formation in cartilage, as well as new insights into the pathogenesis of this common affliction of aging.
Exposure to developmental toxicants may cause fetal malformations, increase prenatal death rates and reduce fetal weight at term. However, there has been little formal study of the relationship among these effects. Certainly, no statistical methods are currently available to jointly analyze these effects of exposure. As a preliminary step in developing such methods, simple exploratory analyses were conducted using a series of ten studies conducted for the National Toxicology Program. Because fetal weight and malformation status were both reported for all live fetuses, the data permitted an exploration of the correlation between these two outcomes. The data show a clear pattern wherein malformed fetuses tended to be lighter at term than nonmalformed fetuses. While these patterns cannot be used to draw inferences regarding the biological relationship between fetal weight and malformation, they do suggest the potential value in developing statistical models for the joint effect of exposure on fetal weight and malformations.
Ascorbate (0-500 microM) stimulates synthesis and secretion of collagen by cartilage explants in a dose-dependent fashion as estimated by [3H]proline incorporation. Concurrent elaboration of inorganic pyrophosphate (PPi) parallels [3H]proline incorporation (less than 0.001, Wilcoxon rank sum). The effect on proline and PPi is abolished by ascorbate oxidase. Another reducing agent, Vitamin E, did not promote PPi accumulation about cartilage. Inhibitors of collagen synthesis, including monensin, tumor necrosis factor alpha, and 2',2'dipyridyl also inhibited PPi elaboration. Cycloheximide (1 micrograms/ml) inhibited the ascorbate stimulated PPi elaboration 54% but did not attenuate the secretion of PPi by unstimulated cartilage. Cosecretion of collagen and PPi by chondrocytes may explain these results. Moreover, at least two pathways exist for PPi elaboration, a cycloheximide sensitive path and another independent of new protein synthesis.
Twenty-three patients with advanced inoperable squamous cell carcinoma of the esophagus were treated with aminothiadiazole (A-TD) 125 mg/m2 weekly plus allopurinol daily in a phase II cooperative group trial. No patients responded to treatment; 17 patients progressed, three showed stable disease, and three were unevaluable. There were no life-threatening hematologic or metabolic toxicities. The median survival from study entry was 5 months. A-TD is not active in advanced squamous cell carcinoma of the esophagus.
The enzyme nucleoside triphosphate pyrophosphohydrolase (NTPPPH) is present in all joint fluids and on intraarticular cells. It generates inorganic pyrophosphate (PPi) from nucleoside triphosphate substrate, thus serving as a potential source of the PPi which forms in the cartilages of patients with calcium pyrophosphate dihydrate (CPPD) crystal deposition. NTPPPH is also important in matrix vesicle induced calcification with basic calcium phosphate (BCP) crystals. An articular substrate for this enzyme was sought. ATP was measured in the joint fluids from 107 patients with various forms of arthritis. Synovial fluid ATP levels were higher in patients with CPPD deposits than in osteoarthritis (p less than 0.02) or rheumatoid arthritis (p less than 0.002). ATP also correlated with PPi concentration (p less than 0.05) and with the presence of BCP crystals (p less than 0.05), but not with cellularity of the fluid, NTPPPH activity, or age of the donor. This substrate for NTPPPH may contribute to CPPD crystal deposition by generating PPi and may stimulate matrix vesicle induced formation of BCP crystals in several forms of arthritis.
Inorganic pyrophosphate (PPi), a product of glycosaminoglycan synthesis, may be cosecreted with matrix proteoglycan to reach the extracellular site where calcium pyrophosphate dihydrate crystals form. To test this hypothesis, sulfated glycosaminoglycan synthesis by articular cartilage in culture was stimulated or inhibited while the effect on extracellular PPi was measured. When stimulated by 0.8 mM xyloside to increase 35SO4 incorporation (mean +/- SEM % of control 183 +/- 16, n = 5), PPi accumulation changed little (from 54 +/- 6 pmoles/mg to 63 +/- 8 pmoles/mg of cartilage wet weight). Inhibition of sulfation with monensin or diethylcarbamazine disproportionately lowered 35SO4 incorporation compared with PPi elaboration. Using 60 mM diethylcarbamazine, PPi production was preserved (105 +/- 8% mean +/- SEM) compared with control cultures, while sulfation was markedly inhibited (7 +/- 1%). This dissociation of sulfate incorporation and PPi secretion indicates that it is not likely that glycosaminoglycan sulfation is the source of the PPi that escapes from chondrocytes to participate in the formation of extracellular crystals.
The disordered production of extracellular inorganic pyrophosphate (PPi) by cartilage contributes to calcium pyrophosphate dihydrate crystal formation and associated diseases. We have previously shown that a factor(s) derived from human platelets markedly stimulates the accumulation of PPi in the media of porcine articular cartilage in organ culture. This is the first known physiologic modifier of PPi production by cartilage. We report herein that platelet derived growth factor (PDGF) is not the platelet factor responsible for PPi stimulation and that the active factor is not mitogenic for chondrocytes. PDGF added to the media of articular cartilage explants in the presence of 0.5% (platelet-poor) plasma (PPP) produces 3.92 +/- 1.6 mumol/L PPi compared with 2.85 +/- 0.7 mumol/L PPi in cartilage exposed to PPP alone. The platelet extract (PE) and PDGF are mitogenic for adult articular chondrocytes in high-density monolayer cultures. Anti-PDGF antibodies block the mitogenic effects of PDGF and PE. The uptake of thymidine labeled with tritium is 157% of control in cells exposed to PE, PPP, and polyclonal goat immunoglobulin G (IgG); 114% of control in cells exposed to PE, PPP, and anti-PDGF antibody; 148% of control in cells treated with PDGF, PPP, and goat IgG; and 98% of control in cells treated with PDGF, PPP, and anti-PDGF antibody. However, anti-PDGF antibody has no effect on PPi accumulation. PPi levels are 17.22 +/- 1.6 mumol/L in media from cartilage treated with PPP, goat IgG, and PE and 17.62 +/- 2.2 mumol/L in cartilage exposed to PE, PPP, and anti-PDGF antibody. We have further characterized the platelet factor responsible for the stimulation of PPi by cartilage. It is not mitogenic for chondrocytes, and it is not PDGF.
The disordered production of inorganic pyrophosphate (PPi) by articular cartilage is thought to have an important role in the pathogenesis of calcium pyrophosphate dihydrate deposition disease and perhaps osteoarthritis. We have previously shown that fetal calf serum added to the culture media of porcine articular cartilage explants increases the elaboration of PPi into the ambient media. We have examined this PPi stimulatory activity by studying the effects of adult human serum (HS), serum derived from adult human plasma (HP), and an acid-alcohol extract of human platelets (PE) on PPi production in cartilage organ culture. Ten percent HS produces a 1.4-fold increase in PPi production after 48 h of culture, while cartilage incubated in media containing 10% HP produces no more PPi than that incubated in media alone. PE stimulates a mean 2-fold increase in PPi production at 48 h in the presence of low concentrations of HP, and has no effect alone. It does not appear to up-regulate the activity of the ectoenzyme nucleoside triphosphate pyrophosphohydrolase (NTPPPH), nor does it promote the release of enzyme substrate into the extracellular space. Cartilage exposed to 0.5% HP and PE has 1.51 +/- 0.36 units of NTPPPH activity whereas cartilage exposed to 0.5% HP alone has 1.52 +/- 0.41 units of enzyme activity. PE does not increase the release of [14C]adenine-labeled compounds into the media. Approximately 13% of soluble 14C counts was found in the media of chondrocytes treated with PE while 18% of counts was released in the presence of HP alone. We have demonstrated a factor or factors present in FCS, HS, and an acid-ethanol extract of human platelets which represent(s) the first known physiologic modulators of PPi production in articular cartilage and may increase PPi production without affecting NTPPPH activity.
Inorganic pyrophosphate elaboration by articular cartilage may favor calcium pyrophosphate dihydrate crystal deposition. Frequently crystal deposits form in persons affected with metabolic diseases. The cartilage organ culture system was used to model these metabolic conditions while measuring the influence on extracellular pyrophosphate elaboration. Alterations of ambient pH, thyroid stimulating hormone levels, and parathyroid hormone levels did not change pyrophosphate accumulation in the media. However, subphysiologic ambient calcium concentrations (25, 100, 500 microM) increased pyrophosphate accumulation about chondrocytes 3- to 10-fold. Low calcium also induced release of [14C]adenine-labeled nucleotides from chondrocytes, potential substrates for generation of extracellular pyrophosphate by ectoenzymes. Exposing cartilage to 10% fetal bovine serum also enhanced by 50% the egress of inorganic pyrophosphate from the tissue.
Deoxyadenosine metabolism was investigated in rabbit growth plate and articular cartilage to elucidate the biochemical basis for the chondro-osseous dysplasia observed in adenosine deaminase (ADA) deficiency. Models of ADA deficiency, the combination of deoxy-adenosine and either of 2 ADA inhibitors, were selectively toxic to immature cartilage, supporting the hypothesis that the chondro-osseous dysplasia of ADA deficiency is the consequence of the enzyme deficiency. Depletion of ATP may play a role in the altered chondrocyte viability and function observed in this model.
Twenty-six patients were referred to the adult sarcoma clinic of the authors' institution between 1979 and 1986. The diagnosis was not confirmed in four patients. The median age of the 22 confirmed patients was 37. Twelve patients had central skeletal primaries; of these 12, seven had metastatic or unresectable disease. Six patients were treated with complete resection of tumor followed by adjuvant chemotherapy; of these six, four remained continuously disease-free at 25+, 29+, 72+, and 75+ months. Eight patients received no adjuvant chemotherapy following complete resection. Four have remained disease-free for more than two years (31, 33, 44, 44+ months); however, only one remains continuously disease-free. Adults tolerated chemotherapy well and should be considered appropriate candidates for adjuvant trials. Many, however, will have advanced-stage, poor-prognosis lesions and require alternative approaches for treatment.
Associations between patient characteristics and survival were investigated in 432 patients with hepatocellular carcinoma. Those patients were prospectively studied by the Eastern Cooperative Oncology Group, and each had his or her diagnosis reconfirmed by a pathology review panel. There were 301 North American and 131 South African patients. Sixty-nine % of the North American patients and 82% of the South African patients were male. There were 187 Black patients, 62 of whom were from North America. The study population is unique among hepatocellular carcinoma patients in that eligibility, evaluability, and endpoint definitions were standardized, and patients from both North America and South Africa received similar treatments at a similar time. Factors with the most significant adverse effect on survival are impaired performance status, male sex, older age, and disease symptoms (jaundice and reduced appetite). There is no apparent difference in survival between White and Black patients within North America, but North American patients survived longer than South African patients. Among the different therapies, p.o. 5-fluorouracil was associated with the poorest median survival time (6 wk), and i.v. 5-fluorouracil plus semustine with the best median survival time (24 wk).
We report a case of calcium oxalate arthropathy in a woman undergoing intermittent peritoneal dialysis who was not receiving pharmacologic doses of ascorbic acid. She developed acute arthritis, with calcium oxalate crystals in Heberden's and Bouchard's nodes, a phenomenon previously described in gout. Intermittent peritoneal dialysis may be less efficient than hemodialysis in clearing oxalate, and physicians should now consider calcium oxalate-associated arthritis in patients undergoing peritoneal dialysis who are not receiving large doses of ascorbic acid.