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Biomedical subjects

D O Clegg

Publications and source records attributed to D O Clegg.

At least 73 records · Page 4Linked to original sources
PubMed1991

Early undifferentiated connective tissue disease. I. Early clinical manifestation in a large cohort of patients with undifferentiated connective tissue diseases compared with cohorts of well established connective tissue disease.

We identified a cohort of 410 patients with connective tissue disorders (CTD) of less than or equal to 1 year duration among the participating clinics of the Cooperative Systematic Studies of the Rheumatic Diseases Program. Fifty-seven had rheumatic arthritis (RA), 57 systemic lupus erythematosus, 37 poly/dermatomyositis, 46 scleroderma, and 213 early undifferentiated CTD, including patients with Raynaud's phenomenon, unexplained polyarthritis or at least 3 CTD manifestations such as rashes, myalgias, etc. Baseline clinical data are now being reported. The followup of these patients may prove to be valuable in understanding these diseases. To our knowledge no similar cohort of patients is available for further investigation.

Adolescent↗
PubMed1991

Early undifferentiated connective tissue disease. II. The frequency of circulating antinuclear antibodies in patients with early rheumatic diseases.

The presence of antinuclear antibodies (ANA) in the serum is a common finding in various connective tissue disorders, but usefulness of these antibodies in making diagnoses or prognoses is not known. We report the results of a panel of ANA determinations including ANA, anti-dsDNA, Sm, RNP, SSA, SSB, Jo-1, Scl-70 and PM-1 in 410 patients in a 5-year descriptive study of 410 patients with rheumatic disease symptoms of less than one year's duration. While some patients met diagnostic criteria for a specific rheumatologic diagnosis, others were classified as undifferentiated connective tissue disease (UCTD) and were subclassified by a constellation of symptoms. Our results show that ANA is sensitive in systemic lupus erythematosus (SLE) and progressive systemic sclerosis even in early disease but is not specific. Other "specific" autoantibodies were seen most frequently in SLE but were relatively insensitive and were seen in low frequency in UCTD. ANA have limited diagnostic value in patients with early disease. The prognostic value of these tests will be assessed as the prospective study of these cohorts progresses.

Antibodies, Antinuclear↗
PubMed1990

Identification and developmental expression of a chicken calsequestrin homolog.

Calsequestrin (CAL) is a calcium-binding protein whose primary function is thought to involve sequestration of calcium in the muscle sarcoplasmic reticulum (SR). Little is known about the mechanisms regulating CAL expression, or about the role of this protein in muscle development. In addition, CAL may regulate calcium localization in some nonmuscle cells. We have identified an avian calsequestrin homolog. The predicted amino acid sequence of the avian CAL, first described as a laminin binding protein, and named aspartactin, is 70-80% identical to mammalian CAL sequences. We have used affinity-purified antibodies and cDNA probes to investigate expression in developing and adult chicken tissues. In adult chickens, the avian CAL homolog was expressed in slow and fast twitch skeletal muscle as well as in cardiac muscle. Surprisingly high levels of CAL protein were also detected in cerebellum. During development, CAL mRNA and protein were detected in Embryonic Day 5 (E-5) limb primordia, well before the initiation of myoblast fusion. In leg skeletal muscle, CAL protein and mRNA increase approximately 10-fold from E-8 to E-18 with a time course that just precedes myoblast fusion. This early expression pattern was also observed in cultured chicken pectoral myoblasts, and appears to be regulated at the level of mRNA abundance. The developmental profile of CAL expression is compared to that of other muscle proteins and possible additional functions of CAL are discussed.

Amino Acid Sequence↗
PubMed1990

Efficient transfection and expression of heterologous genes in PC12 cells.

The PC12 pheochromocytoma cell line has been a favorite model system for cell and neurobiologists, but has proven relatively refractory to standard DNA transfection methods. We have found that the cationic lipid "lipofectin" provides a simple, gentle, and nontoxic procedure that vastly improves transfection efficiencies in PC12 cells. Transient expression of chloramphenicol acetyl transferase (CAT) driven by a Rous sarcoma virus long terminal repeat (LTR) is much more efficient using lipofectin when compared with calcium phosphate as a transfection procedure. Additionally, transient transfection of nerve growth factor (NGF)-differentiated PC12 cells proceeds with equal efficiency relative to naive, uninduced cells. Using the lipofectin procedure, the frequency of stable transfection is 100-fold higher than that reported with standard calcium phosphate precipitation protocols. To examine the effectiveness of different promoters for efficient expression of heterologous DNA in PC12 cells, three different promoter-bearing constructs were utilized. Each construct contains a different promoter sequence upstream from a chicken calsequestrin cDNA. A human cytomegalovirus (CMV) immediate early promoter construct produced the highest level of expression, followed by a human beta-actin promoter construct. Expression from a mouse Moloney sarcoma virus LTR construct could not be detected. These results overcome the previous transfection problems of low efficiency and low viability that have plagued many PC12 cell investigations.

Animals↗
PubMed1990

Liver histology in patients receiving low dose pulse methotrexate for the treatment of rheumatoid arthritis.

The liver histology of 52 patients treated with intermittent low dose pulse methotrexate for rheumatoid arthritis was evaluated using a modification of the Roenigk grading system. Patients studied had had an average of 3.2 years of treatment or had received 1.7 g methotrexate. No patient had cirrhosis; 15 (29%) patients had evidence of mild fibrosis. Histological abnormalities were not predicted by liver function test changes, with the exception that hypoalbuminaemia occurred in 60% of those with grade IV (modified criteria) findings. The need for liver biopsy in patients with rheumatoid arthritis treated with methotrexate before two years or 1500 mg of treatment has not been established. Whether serial liver biopsies will be needed beyond this time has yet to be determined.

Adult↗
PubMed1990

Basic therapy of rheumatoid arthritis: nonsteroidal anti-inflammatory drugs.

Aspirin is recommended for initial therapy of RA. If aspirin is not tolerated, an NSAID is recommended. The choice of NSAID should be based on cost, convenience, safety, and the personal experience of the physician. An adequate trial of at least 2 weeks should be completed before changing to another NSAID. Therapy should be closely monitored for adverse reactions, particularly renal and gastrointestinal effects.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Regulation of nerve growth factor mRNA levels in developing rat heart ventricle is not altered by sympathectomy.

The survival of sympathetic and sensory neurons is known to be controlled by nerve growth factor (NGF) supplied by the targets of innervation, yet little is known about how target NGF synthesis is regulated. We have investigated the pattern of NGF mRNA expression in developing rat heart ventricle using a sensitive RNA blotting procedure. We find that the concentration of NGF mRNA increases steadily from Embryonic Day 17 to peak levels at 10-14 days postnatal and then declines about twofold and stabilizes at the level found in adults. The rise in NGF mRNA concentration correlates with the arrival and differentiation of sympathetic nerve terminals in the heart and the cessation of sympathetic cell death. To assess the role of innervating sympathetic neurons in regulating NGF mRNA expression, neonatal rats were sympathectomized by treatment with 6-hydroxydopamine and heart ventricles were assayed for NGF message. Although this treatment reduced ventricle norepinephrine content by 82%, no significant change in NGF mRNA concentration was observed. These results suggest that the developmental program of NGF mRNA production in the heart is not influenced by innervating sympathetic neurons.

Aging↗
PubMed1989

Amyloidosis and Reiter's syndrome: report of a case and review of the literature.

Reiter's syndrome is classically described as the triad of urethritis, conjunctivitis, and arthritis, It has many manifestations and has rarely been reported to occur in association with amyloidosis. Four cases of systemic amyloidosis have previously been reported. This case describes a patient who developed progressive renal amyloidosis after a 17-year history of severe Reiter's syndrome. Immunofluorescent staining of the renal biopsy was strongly positive for AA protein, the type of protein found in secondary amyloidosis. This is the first case in which amyloidosis has been proven to be secondary to Reiter's syndrome and not merely the coincidental occurrence of two rare diseases.

Amyloidosis↗
PubMed1989

Methotrexate therapy in rheumatoid arthritis: 2-year retrospective followup study.

Clinical and laboratory data in 124 patients with rheumatoid arthritis treated with methotrexate (MTX) were retrospectively reviewed over the initial 2 years after the start of treatment. Clinical improvement occurred in 103 (83%) patients after 12 weeks of treatment. At 2 years of followup, 60 patients (48%) continued to receive MTX with sustained clinical benefit. It has been discontinued in 64 (52%) patients (adverse drug reactions in 38, lack of clinical benefit in 15, and miscellaneous reasons in 11). Patients with adverse drug reactions had higher initial serum creatinine and blood urea nitrogen values than patients without adverse drug reactions.

Adult↗
PubMed1988

One-year experience in patients treated with auranofin following completion of a parallel, controlled trial comparing auranofin, gold sodium thiomalate, and placebo.

Following a 21-week double-blind trial that compared the effects of treatment with auranofin (AUR), gold sodium thiomalate, and placebo in 193 patients, 147 patients entered a 1-year, open-label study of treatment with AUR (6 mg/day). Results of this open-label study suggest that AUR has a long-term use profile similar to that of other slow-acting antirheumatic drugs. AUR appears to be capable of sustaining an initial response to gold sodium thiomalate. The withdrawal rate remains relatively high: Nearly half of the study patients had discontinued AUR by the end of 1 year.

Adolescent↗
PubMed1988

A controlled trial comparing sulfasalazine, gold sodium thiomalate, and placebo in rheumatoid arthritis.

One hundred eight-six patients with active rheumatoid arthritis were evaluated in a double-blind, randomized study that compared treatment with sulfasalazine (SSZ) (2 mg/day), gold sodium thiomalate (GST) (50 mg/week), and placebo (PBO). The 37-week course of therapy was completed by 109 patients. While marked improvement was seen in all 3 treatment groups, the only statistically significant differences between SSZ or GST and PBO were in a decreased erythrocyte sedimentation rate and increased grip strength in the right hand. GST is known to be superior to PBO, and the response of the GST-treated group was similar to that seen in other trials. The response of the PBO group, however, was much greater than in other placebo groups we have studied. SSZ was similar in efficacy to injectable gold, but was better tolerated. Because of adverse drug reactions (most commonly, rash, stomatitis, and proteinuria), 41% of patients were withdrawn from the GST treatment. Untoward drug effects (most frequently, rash and gastrointestinal distress) caused 16% of patients to be withdrawn from SSZ therapy.

Adolescent↗
PubMed1988

Hepatic ultrastructure after methotrexate therapy for rheumatoid arthritis.

Twenty-six patients receiving long-term oral methotrexate (MTX) therapy for rheumatoid arthritis (24 patients) or psoriasis (2 patients) were prospectively evaluated for alterations in liver morphology by light microscopy, electron microscopy, and immunofluorescence microscopy. Although only 4 MTX-treated patients had light microscopic evidence of mild fibrosis, all had evidence of collagen deposition in the space of Disse near Ito cells and changes in hepatocyte lysosomes on electron microscopy. These findings were absent from control livers. Fibrinogen, fibronectin, and type IV collagen were identified by immunofluorescence in both MTX-treated patients and controls. We conclude that long-term MTX therapy for rheumatoid arthritis is associated with alterations in hepatic ultrastructure, including collagen deposition in the space of Disse and changes in hepatocyte lysosomes.

Adult↗
PubMed1988

Amino acid sequence and distribution of mRNA encoding a major skeletal muscle laminin binding protein: an extracellular matrix-associated protein with an unusual COOH-terminal polyaspartate domain.

Two cDNAs encoding an abundant chicken muscle extracellular matrix (ECM)-associated laminin-binding protein (LBP) have been isolated and sequenced. The predicted primary amino acid sequence includes a probable signal peptide and a site for N-linked glycosylation, but lacks a hydrophobic segment long enough to span the membrane. The COOH terminus consists of an unusual repeat of 33 consecutive aspartate residues. Comparison with other sequences indicates that this protein is different from previously described LBPs and ECM receptors. RNA blot analysis of LBP gene expression showed that LBP mRNA was abundant in skeletal and heart muscle, but barely detectable in other tissues. Blots of chicken genomic DNA suggest that a single gene encodes this LBP. The amino acid sequence and mRNA distribution are consistent with the biochemical characterization described by Hall and co-workers (Hall, D. E., K. A. Frazer, B. C. Hahn, and L. F. Reichardt. 1988. J. Cell Biol. 107:687-697). These analyses indicate that LBP is an abundant ECM-associated muscle protein with an unusually high negative charge that interacts with both membranes and laminin, and has properties of a peripheral, not integral membrane protein. Taken together, our studies show that muscle LBP is a secreted, peripheral membrane protein with an unusual polyaspartate domain. Its laminin and membrane binding properties suggest that it may help mediate muscle cell interactions with the extracellular matrix. We propose the name "aspartactin" for this LBP.

Amino Acid Sequence↗
PubMed1987

Lack of association between HLA-DR2 and clinical response to methotrexate in patients with rheumatoid arthritis.

Recent studies have indicated an association between the HLA-DR2 phenotype and substantial response to methrotrexate in patients with rheumatoid arthritis (RA). To further resolve this issue, we analyzed this relationship. Our data, obtained from a multicenter, double-blind study of rigorously assessed patients with RA, demonstrated that neither HLA-DR2 nor any other HLA-DR specificity is significantly associated with a substantial clinical response to methotrexate in patients with RA.

Arthritis, Rheumatoid↗
PubMed1987

Low dose pulse methotrexate in rheumatoid arthritis: an 8-year experience with hepatotoxicity.

The clinical utility of standard liver function tests for monitoring low dose pulse methotrexate therapy is reviewed in 163 rheumatoid arthritis patients over an eight-year period. Abnormalities of hepatic enzymes were seen in 58% of patients but led to cessation of therapy in only 5%. Moderate alcohol intake did not affect the frequency of liver test abnormalities. Abnormalities were seen more frequently in patients with longer duration of methotrexate therapy and in those with higher total dose. There was no correlation between liver test abnormalities and day of serum sampling relative to day of methotrexate dosing, nor was a correlation seen between liver test abnormalities and total weekly dose of methotrexate. Methotrexate has been demonstrated to be an effective drug in the treatment of rheumatoid arthritis. The clinical utility of standard liver tests to predict the potential for hepatotoxicity is questionable.

Adult↗
PubMed1987

Pulmonary disease during the treatment of rheumatoid arthritis with low dose pulse methotrexate.

Methotrexate therapy has been effective in the treatment of RA with short term experience suggesting little serious adverse reactions. Our review of 168 patients receiving methotrexate has identified nine patients with probable or possible methotrexate-induced pulmonary toxicity, giving a prevalence of 5% and an incidence of 3.9 per 100 patients per year. No clinical or laboratory features showed an association that could potentially predict the development of pulmonary disease. All patients experienced complete recovery with supportive care and/or corticosteroid therapy. Clinical monitoring for this complication is warranted in all patients receiving long term methotrexate therapy for RA.

Adult↗