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Biomedical subjects

J Coll

Publications and source records attributed to J Coll.

At least 55 records · Page 3Linked to original sources
PubMed1995

Further characterization of the human cell multiprotein DNA replication complex.

Evidence for multiprotein complexes playing a role in DNA replication has been growing over the years. We have previously reported on a replication-competent multiprotein form of DNA polymerase isolated from human (HeLa) cell extracts. The proteins that were found at that time to co-purify with the human cell multiprotein form of DNA polymerase included: DNA polymerase alpha, DNA primase, topoisomerase I, RNase H, PCNA, and a DNA-dependent ATPase. The multiprotein form of the human cell DNA polymerase was further purified by Q-Sepharose chromatography followed by glycerol gradient sedimentation and was shown to be fully competent to support origin-specific and large T-antigen dependent simian virus 40 (SV40) DNA replication in vitro [Malkas et al. (1990b): Biochemistry 29:6362-6374]. In this report we describe the further characterization of the human cell replication-competent multiprotein form of DNA polymerase designated MRC. Several additional DNA replication proteins that co-purify with the MRC have been identified. These proteins include: DNA polymerase delta, RF-C, topoisomerase II, DNA ligase I, DNA helicase, and RP-A. The replication requirements, replication initiation kinetics, and the ability of the MRC to utilize minichromosome structures for DNA synthesis have been determined. We also report on the results of experiments to determine whether nucleotide metabolism enzymes co-purify with the human cell MRC. We recently proposed a model to represent the MRC that was isolated from murine cells [Wu et al. (1994): J Cell Biochem 54:32-46]. We can now extend this model to include the human cell MRC based on the fractionation, chromatographic and sedimentation behavior of the human cell DNA replication proteins. A full description of the model is discussed. Our experimental results provide further evidence to suggest that DNA synthesis is mediated by a multiprotein complex in mammalian cells.

Blotting, Western↗
PubMed1995

Antibodies to human immunodeficiency virus (HIV-1) in autoimmune diseases: primary Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis and autoimmune thyroid diseases.

The aetiology of autoimmune diseases remains unknown. The relationship between virus, and more recently retrovirus, has been suggested with this group of diseases. Immunoblotting is a useful method for determining the presence of proteins coded by different retrovirus genes. Since the prevalence of these types of proteins in patients with primary Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and autoimmune thyroid diseases has not been fully established, the aim of this work was to determine the prevalence of antibodies to immunodeficiency human virus type 1 (HIV-1) proteins in these diseases and their possible relationship with the presence of anti-nuclear, anti-DNA, anti-SSA (Ro) and anti-SSB (La) autoantibodies. Antibodies to human immunodeficiency virus (HIV-1) were studied in a group of 341 patients with autoimmune diseases (77 SS, 98 SLE, 75 RA, 91 autoimmune thyroid diseases) and 126 blood donors as a control group. A Western blot was used to detect antibodies to HIV-1, and a double polymerase chain reaction (PCR) using nested primers in the gag and pol gene of HIV-1. Antinuclear antibodies, anti-DNA, anti-SSA (Ro) and anti-SSB (La) were determined by enzyme-linked immunosorbent assays. At least one band was shown on immunoblotting in 26% of patients with autoimmune diseases and 35% of controls. The presence of antibodies to p55 or p68 proteins in patients with SS or SLE proved to be the only statistically significant difference between the other autoimmune diseases studied and the control group. These antibodies were not associated with autoantibodies ANA, DNA, SSA (Ro) or SSB (La).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Desmin myopathy: a multisystem disorder involving skeletal, cardiac, and smooth muscle.

Myopathy associated with desmin-type intermediate filaments is an uncommon disorder of skeletal and/or cardiac muscle. The present study focuses on a 28-year-old man with generalized muscular atrophy, cardiomyopathy, and intestinal malabsorption and pseudo-obstruction. Abundant sarcoplasmic granular and filamentous aggregates that were ultrastructurally continuous with Z lines or dense bodies and exhibited intense immunostaining for desmin were present throughout the skeletal musculature, myocardium, and smooth muscle of the intestine. Moreover, neurofilament-immunoreactive axonal spheroids were identified in the spinal cord and roots. These widely distributed findings illustrate the multisystemic character of desmin myopathy, which in this instance first adds intestinal smooth muscle involvement to its already known skeletal and cardiac muscle manifestations. The additional presence of neurofilament aggregates in the spinal cord and roots constitutes an extremely rare conjunction of intermediate filament pathology of the neuromuscular system.

Adult↗
PubMed1995

The H19 gene is expressed within both epithelial and stromal components of human invasive adenocarcinomas.

In a previous work, we have isolated the human H19 gene and shown accumulation of transcripts in various human tumors including breast carcinomas (Douc-Rasy et al (1993) Int J Oncol 2, 753-758). Questions arose, after Northern blot results, about the precise H19 mRNA location, specially in normal breast tissues and benign or malign primary breast tumors. Then we performed molecular in situ hybridization to get insight into tissue expression of the H19 gene. Examined resections included one normal tissue, one fibroadenoma and 13 cancers. Results obtained with the H19 probe can be summarized as follows: 1) in normal breast tissues signals were focally observed in epithelial cells, but more predominantly in the palleal tissue which is sensitive to hormones; 2) in the fibroadenoma, fibroblastic cells were extensively labeled at the stroma-epithelium boundary, but epithelial cells were negative; and 3) in primary cancers, eight specimens exhibited signals on stromal cells, one specimen on epithelial cells and four on both epithelial and stromal cells. Data provide the following evidence: 1) usually labeled cells are clustered, either within normal or pathological tissues; 2) the labeling pattern highly differs from one tumor to another; and 3) H19 probe displays very different signals from one cell to another in given compartment of a given tissue section. In conclusion, it seems that a high H19 expression matches the tumor invasion. Our results suggest that the expression of this gene is concerned by the relationships between epithelial and stromal cells, and can reflect peculiar physiological states of the cells. Furthermore, we discuss results showing an abundant expression of H19 gene in some adenocarcinomas of bad prognosis, in the context of the otherwise established tumor-suppressor role of this gene, or the strictly controlled gene dosage, which could be overridden in these particular cases.

Adenocarcinoma↗
PubMed1995

Bone remodelling in human immunodeficiency virus-1-infected patients. A histomorphometric study.

The aim of this study was to identify and describe possible alterations of bone histomorphometry in patients with human immunodeficiency virus (HIV-1) infection and to assess the relation between these alterations and disease severity. Forty-four HIV-1-infected patients seen successively at our hospital were evaluated for the study. In an attempt to avoid confounding factors as far as possible, we excluded patients who fulfilled any of the following criteria: age less than 18 or greater than 40 years; recent history of extended bed rest; previous diagnosis of metabolic bone disease, renal insufficiency, or hepatic failure; clinical or echographic signs of liver cirrhosis; diabetes mellitus or previous diagnosis of other endocrine diseases; drug therapy that could act on bone metabolism; and/or moderate to severe nutritional alteration. Twenty-two patients (13 men, 9 women; age: 27.9 +/- 4.1 years, mean +/- standard deviation) were included in the study. Plasma and urine biochemistry and calcium-regulating hormones were determined. Bone mineral content was measured on vertebrae L2 to L4 and on the neck and intertrochanteric areas of the femur by dual-photon absorptiometry. A transiliac bone biopsy was performed after double-tetracycline labelling, with histomorphometric study of undecalcified bone. Serum osteocalcin was found to be lower in patients who, according to the Centers for Disease Control (CDC) classification, had greater disease severity, and showed a positive correlation with the number of CD4+ T lymphocytes. No alterations in bone densitometry were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Classic Kaposi's sarcoma with pulmonary involvement in an HIV-negative woman.

Visceral involvement in HIV-negative patients with classical Kaposi's sarcoma (KS) has been described only rarely. An unusual case of a 75-year-old Jewish woman with the classical form of KS who presented with cutaneous and pulmonary involvement is presented. Results of several tests for HIV antibodies were negative.

Aged↗
PubMed1995

Interleukin-2 receptor expression in salivary glands of patients with Sjögren's syndrome.

OBJECTIVE: To study interleukin-2 receptor (IL-2R) expression in lymphocytic and epithelial cells in salivary glands of patients with Sjögren's syndrome (SS). METHODS: Minor salivary glands of 29 patients with primary SS, 28 with secondary SS, 19 with autoimmune diseases without SS, and 17 controls were studied using immunohistochemical techniques. Sections were analyzed with 3 different antibodies reacting with CD25 molecule. RESULTS: The presence of IL-2R (CD25) was observed in minor salivary gland lymphocytic infiltrate in 26 (89.6%) primary SS, 24 (85.7%) secondary SS, and 16 (84%) autoimmune diseases without SS. CD25 antibody was expressed in epithelial cells in 12 (41%) patients with primary SS and 11 (39%) with secondary SS, but was absent in the group of autoimmune diseases without SS and the control group. CONCLUSION: The lymphocytic infiltrate of minor salivary gland expressed IL-2R in patients with primary SS, secondary SS and autoimmune diseases without SS. IL-2R expression in epithelial cells was only present in patients with primary or secondary SS.

Antibodies, Monoclonal↗
PubMed1995

Autoimmune sialadenitis: a form of onset of Sjögren's syndrome?

We analyzed phenotype, activation factors and adhesion molecules in minor salivary glands of patients with incomplete Sjögren's syndrome (SS) criteria and those with autoimmune diseases without defined SS criteria who presented non-specific sialadenitis. These data were correlated with those observed in patients with established SS. A total of 76 minor salivary gland biopsies were analyzed. Twenty-five patients had defined SS, 23 probable SS and 28 had diffuse infiltrates without forming foci (12 had probable SS and 16 had autoimmune disease without associated SS). When a group of 23 patients with focal infiltrates ("focal sialadenitis") and probable SS was compared with another of 25 with defined SS, no significant differences were detected in the phenotype, activation or adhesion molecules studied or in HLA-DR expression in epithelium. In patients with diffuse infiltrate ("non-specific sialadenitis"), no differences were found in phenotype cell activation molecules expression was observed in the lymphocytes of some biopsies of patients with autoimmune disease without SS, though without statistical significance. Statistically significant differences were found in HLA-DR expression in epithelium.

Autoimmune Diseases↗
PubMed1995

Central nervous system disease in Sjögren's syndrome.

Our prospective study consisted of a general and neurological evaluation in 48 patients (41 females, 7 males; mean age: 58.2 years) with primary Sjögren's syndrome (PSS). We performed serologic studies and cranial magnetic resonance imaging (MRI). Main extraglandular features were arthralgias and non-erosive arthritis (37.5%). Raynaud (21%) and pulmonary fibrosis (12.5%). Antinuclear antibodies were positive in 42.5% and anti-SS-A (Ro) in 20%. Migraine (52%), neuropsychiatric disease (29%) and a past history of focal acute neurological deficits (23%), were the central nervous system (CNS) manifestations more frequently observed. Cranial MRI examination detected hyperintense small subcortical lesions in 51.3% of patients and in 36.6% of age and sex matched controls (P < 0.001). CNS disease was not serious concerning vital prognosis, but produced significant morbidity in some patients. Late onset "migraine-like" episodes with prolonged sensoromotor deficits and coexisting neuropsychiatric disease emerged as a characteristic clinical spectrum in those patients diagnosed in a neurological setting. Cranial MRI was frequently abnormal, but findings were not specific. Neurologic manifestations reminiscent of multiple sclerosis were rarely seen.

Aged↗
PubMed1994

The Ets family of proteins: weak modulators of gene expression in quest for transcriptional partners.

Members of the Ets family of transcriptional regulators play pivotal roles in physiological processes, such as embryonic development or immune response. The Ets family proteins possess unique regulatory features because they bind DNA as monomers and their respective activities rely more on their ability to interact with other transcription factors than on their specific binding to a cognate DNA sequence. This review focuses on such interactions and also explores dysregulated expression of the Ets proteins in human cancers.

Amino Acid Sequence↗
PubMed1993

Preliminary criteria for the classification of Sjögren's syndrome. Results of a prospective concerted action supported by the European Community.

OBJECTIVE: Different sets of diagnostic criteria have been proposed for Sjögren's syndrome (SS), but none have been validated with a large series of patients or in a multicenter study. We conducted the present study involving 26 centers from 12 countries (11 in Europe, plus Israel), with the goals of reaching a consensus on the diagnostic procedures for SS and defining classification criteria to be used in epidemiologic surveys and adopted by the scientific community. METHODS: The study protocol was subdivided into two parts. For part I, questionnaires regarding both ocular and oral involvement were developed; they included 13 questions and 7 questions, respectively. For part II a limited set of diagnostic tests was selected, and the exact procedure to be followed in performing these tests was defined. Part I of the study included 240 patients with primary SS and 240 age- and sex-matched controls. Two hundred forty-six patients with primary SS, 201 with secondary SS, 113 with connective tissue diseases but without associated SS, and 133 control patients were studied in part II. RESULTS: The study resulted in (a) the validation of a simple 6-item questionnaire for determination of dry eyes and dry mouth, which showed good discriminant power between patients and controls, to be used in the initial screening for sicca syndrome; and (b) the definition of a new set of criteria for the classification of SS. The sensitivity and specificity of the criteria in correctly identifying patients with either the primary or the secondary variant of SS were also determined. CONCLUSION: Using the findings of this prospective multicenter European study, general agreement can be reached on the diagnostic procedures to be used for patients with SS. Final validation of the preliminary classification criteria for SS is underway.

Connective Tissue Diseases↗