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Results for “THYMUS HYPERPLASIA”

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At least 199 records · Page 11Linked to original sources
PubMed1993

Clinical implementation of anti-acetylcholine receptor antibodies.

A multivariate analysis of anti-acetylcholine receptor (AChR) antibodies and clinical parameters other than treatment (modified Osserman groups, age, type of onset, sex, and thymus pathology) was performed for all incident (n = 366) myasthenia gravis (MG) cases in its white population in Denmark during the past 15 years. Sera from 244 healthy individuals and from 295 patients with diseases other than MG were analysed as controls. Formal statistics for the anti-AChR antibodies assay (immunoprecipitation RIA using crude human AChR extract) were calculated. The distribution of antibodies titres greater than 0.1 nMole/l was found to be approximately lognormal. For MG patients the 95% reference interval was 0.2-1549 nMoles/l, and in control sera the range was 0.0-0.4 nMole/l. Using 0.5 nMole/l as the cut-off level and regarding all results less than this value as normal titres, it appeared that the assay was highly specific (> 99.99%) for MG. In a population of MG patients significance should be attributed to values in the range 0.3-0.4 nMole/l. The overall diagnostic sensitivity was found to be 88%. The sensitivity appeared to be proportionate to clinical severity of MG. The percentage with a normal titre was higher (16%) for early onset of MG, compared with 7% for late onset. No significant difference in relation to the frequency of "negative titre" was found in relation to sex. Anti-AChR antibodies titre was found to correlate with clinical severity, female or male gender, and pathology of thymus. The groups of MG patients were not matched for the various clinical parameters but multiple regression analysis controlling for these variables revealed independent effects of clinical severity and sex though not of age. Normal thymus (including involuted gland) and thymoma were correlated with low to intermediate tires, and hyperplastic thymus with high level of antibodies. The clinical implementation of anti-AchR antibodies is reviewed from 1976 and up to the present. The problems with false positive results are thoroughly expounded.

Antibodies↗
PubMed1986

Myasthenia gravis: monoclonal antihuman acetylcholine receptor antibodies used to analyze antibody specificities and responses to treatment.

We investigated the heterogeneity of serum antibodies to acetylcholine receptor (AChR) by competition with nine antihuman monoclonal antibodies in a cross-sectional study of 36 patients with myasthenia gravis (MG), and in three who showed clinical improvement associated with decrease in total anti-AChR following immunologic treatment. Two specificities were more prevalent in patients without thymoma, an done of these was more prevalent in cases beginning before age 40. Some specificities were stable during serial studies, whereas other fluctuated. We found evidence of three groups of antibody specificities that had different control mechanisms and may define different regions of the receptor.

Adult↗
PubMed1976

Thymic diseases as revealed by a series of consecutive thymectomies and biopsies from the thymus.

A series of 85 thymis biopsies and specimens from thymectomies were re-examined. Forty-five of these were taken from patients with myasthenia gravis. A relatively low frequency of thymitis (57%) was found in these patients, while the frequency of thymoma (9%) was as expected. Two cases of thymitis in thyrotoxicosis were included in the material. In all, 22 thymomas of various kinds (18% of the total material) were diagnosed. A fairly low proportion of these thymomas (18%) were from patients with myasthenia gravis.

Adolescent↗
PubMed1999

[Determination of prognostic factors in surgical treatment of myasthenia gravis].

The authors evaluated, using statistical analysis, the importance of prognostic factors in patients subjected to thymectomy on account of myasthenia gravis. The results revealed a better prognosis of the disease, if the history was less than 6 months, preoperative treatment less than 1.5 years, a histological finding of thymus hyperplasia, second clinical stage according to Ossermann and the patients age below 30 years. From the statistical analysis ensues that the prognosis of myasthenia gravis is more favourable when the case-history is shorter as a result of rapid diagnosis and when preoperative treatment is reduced to a minimum.

Adult↗
PubMed1999

Thymic disorders and myasthenia gravis: genetic aspects.

Myasthenia gravis (MG) is an autoimmune disease characterized by production of antibodies to acetylcholine receptor at the motor end-plate responsible for impairment of neuromuscular transmission. There is general agreement about the involvement of the thymus in the pathogenesis of MG, and thymic pathological changes are commonly found in MG patients. Genetic factors seem to play an important role in susceptibility to MG. As with other autoimmune diseases, genetic predisposition to MG probably involves multiple genes. Ample evidence suggests that genes within the major histocompatibility complex (MHC) are involved in susceptibility to autoimmune diseases. Both data from the literature and our findings indicate that different genes within the MHC could predispose to various forms of MG, and that particularly the tumour necrosis factor genes may play a role in the association between the different thymic disorders and MG.

Case-Control Studies↗
PubMed1976

Myasthenia gravis: mitotic activity of thymus-dependent and blood-lymphocytes.

The thymus and blood lymphocytes of 20 thymectomized patients with myasthenia gravis, including 3 cases of thymoma, have been studied for mitotic activity (spontaneous mitotic activity of native thymocytes, responsiveness of cultured cells to PHA, DNA-polymerase specific activity). The myasthenic thymus gland was found to be the site of a spontaneous DNA-synthesis of similar intensity as the mitotic activity of the thymus in infancy. This was also reflected by the DNA-polymerase activity of the cells. While the thymocyte cultures responded well to PHA stimulation in 50% of the cases, the blood-lymphocytes were found unresponsive. There was a partial correlation between the individual parameters of mitotic activity, but practically none between the mitotic activity and the clinical severity of myasthenia or the histological features of the thymus or of thymoma. Except in the latter cases, a correlation was found between mitotic activity and preoperative immunosuppressive treatment. It is suggested that the T-lymphocytes are not directly involved in the pathomechanism of myasthenia gravis.

Adolescent↗
PubMed2001

The thymus. Pediatric surgical aspects.

Since the original description of thymic death in an infant 400 years ago, the thymus has been recognized as an important structure to practitioners caring for infants and children. The source of many cysts, masses, and tumors in the neck and mediastinum, the thymus gland merits the pediatric surgeon's attention. The thymus is clearly an important lymphoid organ, the removal of which may be therapeutic in MG, but congenital absence leads to profound cell-mediated immunodeficiency. The immunologic sequelae of its neonatal extirpation remains obscure. It is apparent that further research is needed to clarify the functional role of the thymus gland in the developing immune system. Until better elucidated, a conservative approach to neonatal thymectomy may be justified.

Child↗
PubMed2001

Imaging of the thymus.

Technologic advances in imaging, particularly CT and MR imaging, have revolutionized the ability to noninvasively image the thymus. Increasing knowledge of the normal and pathologic states of the thymus has been accompanied by an increasing ability to depict morphologic alterations in this gland with fine spatial resolution and can even provide functional information. This article discusses the role of various imaging modalities in identifying suspected thymic disease, which historically required surgery to visualize. The role of imaging is best understood with an appreciation of the embryology, anatomy, and pathology of the thymus.

Adult↗
PubMed2002

A comparative study of ocular and generalized myasthenia gravis.

We compared the relations and therapeutic outcomes of ocular and generalized types of myasthenia gravis (MG) and used retrospective analysis for 65 patients with myasthenia gravis during a mean follow-up time of 30.4 months. There were 35 ocular and 30 generalized MG patients. Items of comparison included sex, age, clinical presentations, serum antibody titer, the association with thymus status, and therapeutic outcome. Of the patients with generalized MG, males were significantly older than females. Ptosis and diplopia were the most common symptoms in patients with MG, but there were no significant differences between the two types of MG. The eyelid levator muscle and lateral rectus muscle were the most commonly involved extraocular muscles in patients with MG. The associations with thymoma or thymus hyperplasia were more common in generalized MG than in ocular MG, and more common in younger than in older patients. The result of positive neostigmine test was 93.8% in all patients, but there were no significant differences between the two types of MG. Acetylcholine receptor antibody (AchRAb) presented an 81.1% positive rate and was significantly higher in generalized MG than that in ocular MG (96.2% vs 66.7%). There were no significant differences between the two types of MG regarding successful treatment strategies in both initial therapy and maintenance therapy. Only two of 16 patients had complete remissions after thymectomy. From the viewpoint of clinical presentations or from the therapeutic strategy outcome, the boundary between both types of MG seems to be vague. Both types of MG probably share the same entity in nature and the difference is just a matter of degree of severity. The benefit of thymectomy in treatment of MG needs further investigation.

Adolescent↗