Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “THYMECTOMY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1993

Do thymic-neuroendocrine interactions play a role in the antihypertensive effect of neonatal thymectomy in Lyon hypertensive rats?

Previous studies showed that neonatal thymectomy prevented the spontaneous increase in blood pressure in genetically hypertensive rats (LH) of the Lyon strain, leaving untouched that of their normotensive controls (LN). As the thymus is connected to the neuroendocrine system through secretion of hormonal factors, we investigated the possible role played by these factors in hypertension of LH rats. To that end we studied, in sham-operated and neonatally thymectomized LH rats, the blood pressure effects of thymostimulin, a partially purified thymus extract and examined whether changes in major neuroendocrine factors of blood pressure regulation occurred in thymectomized LH rats. Thymostimulin (1 or 10 mg/kg/48 h) did not modify blood pressure in sham-operated LH rats and failed to consistently increase it in neonatally thymectomized animals. Urinary mineralocorticoids, catecholamines and their metabolites, and plasma renin levels were not altered by neonatal thymectomy. Plasma testosterone was decreased to a similar degree by neonatal thymectomy in LH and normotensive controls. These results do not favor a pressor role of thymic hormonal factors in LH rats and show that the antihypertensive effect of neonatal thymectomy is not secondary to a decreased secretion of catecholamines, renin, mineralocorticoids, and testosterone. They therefore suggest that the role of the thymus in genetically hypertensive LH rats is more likely mediated by cellular immune mechanisms than by hormonal processes.

Animals↗
PubMed1988

Modulation by neonatal thymectomy of the reproductive axis in male and female rats during development.

The effects of neonatal thymectomy, at 3 days of age, on parameters of the reproductive axis were examined in male and female Sprague-Dawley rats. Gonadal and accessory sex tissue (male: epididymis, seminal vesicle, and ventral prostate; female: uterus) weights as well as anterior pituitary, spleen, and adrenal weights were determined in the thymectomized and sham-thymectomized animals at 20, 30, 40, 50, 60, and 90 days of age. Plasma gonadotropin concentrations as well as pituitary content of the gonadotropins and prolactin were assessed at each of these time intervals. No significant difference in gonad and accessory sex tissue weights was detected in thymectomized versus sham-operated controls at each of these times. Adrenal weights were increased in thymectomized animals compared with controls at 50 days of age and older in male rats and at 90 days in females. Spleen weights were decreased in the thymectomized males at 50 and 60 days of age. Thymectomy did not affect the spleen weight of females. Plasma concentrations of gonadotropins were unaffected in thymectomized males but were altered in females during the pre- and peripubertal period (Days 20-40). Vaginal opening, however, occurred at the same time in the thymectomized and control females. Pituitary gonadotropin and prolactin content were unaffected by thymectomy of the females, except at 90 days when pituitary luteinizing hormone (LH) content was lower in thymectomized than in control animals. LH and prolactin content were significantly reduced in the males at 60 and 90 days of age. These results demonstrate that there are sexual differences in the effects of thymectomy on parameters of the reproductive axis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

The value of thymectomy in myasthenia gravis: a computer-assisted matched study.

In the absence of a prospective randomized study of patients treated conservatively or with thymectomy, a computer-assisted retrospective matches study was devised. Of 563 patients treated for myasthenia gravis without thymoma up to 1965, 104 had thymectomy. With computer assistance, each surgical patient was matched with a medical patient on the basis of age, sex, and severity and duration of disease. On this basis 80 of the 104 surgical patients could be matched satisfactorily. There were 16 males and 64 females in each of the matched surgically treated and medical control groups. A complete remission was experienced by 27 of the 78 patients in the surgical group as compared to 6 of the medical group. Improvement was noted by 26 of 78 surgically treated patients and 13 of 78 receiving medical treatment. Survival for patients having thymectomy. Thirty-four patients in the medical group had died as compared to 11 in the surgical group. Comparison of survival in relation to sex, duration of symptoms, or age (less than 30 or less than 30 years) did not show a significant difference. Until more effective treatment is available for myasthenia gravis, thymectomy deserves consideration for both sexes, and with increased age or long duration of symptoms.

Adolescent↗
PubMed1985

Thymectomy for myasthenia gravis: 14-year experience.

Forty-eight consecutive patients with myasthenia gravis (MG) attended by generalized weakness were treated by complete thymectomy, performed transsternally in 46 patients and through a left thoracotomy in two with thymomas. There were no operative deaths. A 12-year-old child with fulminating MG died of acute pneumonia shortly after hospital discharge. Of the remaining 47 evaluable patients, thymectomy resulted in complete remission in six, marked improvement with a reduced need for medication in 20, and mild improvement on the same dosage of medication in 18. Neither the age of the patient, nor the histopathology of the excised thymus, nor the postoperative change in acetylcholine receptor antibody titer were found to have a significant influence on the response to thymectomy. If the ten patients who were 20 years of age or younger were excluded, the patients with a shorter duration of MG achieved a better response to operation. The authors conclude that thymectomy is effective treatment for MG, regardless of the age of the patient or the type of thymic pathology.

Adolescent↗
PubMed1996

Long-term outcome and quality of life after thymectomy for myasthenia gravis.

OBJECTIVE: The authors identify criteria suitable to predict long-term clinical improvement and evaluate quality of life after thymectomy for myasthenia. DESIGN: Retrospective analysis with long-term follow-up (mean 92 months) was conducted for 86 patients and questionnaire interviews were performed for 65 patients who underwent thymectomy between 1976 and 1993. MAIN OUTCOME MEASURES: The authors used the Osserman Score and the European Organization for Research and Treatment of Cancer quality-of-life questionnaire. RESULTS: After thymectomy, lasting benefits were achieved predominantly by patients with moderate and severe myasthenia, and this association was significant (p < 0.001) in both bivariable and multiple analyses. No correlation was observed between outcome and thymic pathology, patient age or gender, duration of disease, preoperative plasmapheresis, and medication. Restitution to normal was complete at most recent follow-up as to physical status, working ability, and cognitive and social functions, but some emotional and vegetative deficits remained. CONCLUSION: Future patient selection for thymectomy should-apart from those with suspected thymoma-concentrate on patients with moderate and severe myasthenia unresponsive to conservative management.

Adult↗
PubMed1983

Myasthenia gravis and pregnancy: a reappraisal of thymectomy.

A retrospective review of pregnancy in patients with myasthenia gravis at Duke University was conducted. Twelve new cases of pregnancy in eight myasthenic mothers are reported. In general, thymectomy was the primary treatment modality in these patients and preceded the gestational period in all cases. The clinical course of myasthenia gravis in these pregnancies prompted a literature review of previous case reports. Comparison of clinical symptomatology, course of disease, and maternal and perinatal morbidity and mortality revealed that the incidence of clinical exacerbation was less in the thymectomy than in the nonthymectomy group. The role of the thymus in the pathogenesis of myasthenia gravis is reviewed. The rationale for the use and timing of thymectomy in the treatment of the myasthenic patient is presented. This review supports the continued use of thymectomy for the initial treatment of the young, nonpregnant myasthenic female patient.

Adolescent↗
PubMed2003

Thymectomy for myasthenia gravis: analysis of controversies--patient management.

BACKGROUND: Debate continues regarding the effectiveness of thymectomy in the treatment of nonthymomatous autoimmune myasthenia gravis primarily because there have been no controlled prospective studies. The debate is compounded by the lack of recognition that all thymectomies are not equal in extent or effectiveness and by the fact that all the studies are retrospective without common definitions of myasthenia gravis manifestations or response to therapy. In addition, the analysis of data is often inappropriate. REVIEW SUMMARY: Evidence is presented demonstrating that the extent of the various thymic resectional techniques is very variable and often incomplete and that the more complete the thymic resection the better the results. The indications for thymectomy, the selection of the technique of the resection, the reoperations issue, the perioperative management of the myasthenia gravis patient, morbidity and mortality, and appropriate methods of outcome research are also reviewed. CONCLUSION: In view of the impressive results associated with a complete thymic resection in the treatment of myasthenia gravis, patients should not be denied this operation because of lack of prospective proof to-date, and when a thymectomy is performed a total resection is indicated.

Humans↗
PubMed1988

Mineralocorticoids are not involved in the antihypertensive effect of neonatal thymectomy in the genetically hypertensive LH rat.

1. In order to determine whether the antihypertensive effect of neonatal thymectomy in genetically hypertensive rats could be mediated through altered adrenal function, systolic blood pressure (SBP) and urinary excretion of deoxycorticosterone (DOC), corticosterone (B) and aldosterone were measured in thymectomized hypertensive (LH), normotensive (LN) and low-blood pressure (LL) rats of the Lyon strain. Sham-operated animals served as controls. 2. Neonatal thymectomy prevented the spontaneous increase of SBP in LH rats while it slightly decreased the SBP of LN and did not change that of LL rats. 3. Five week old sham-operated LH rats exhibited an increased urinary excretion of DOC and a decreased excretion of B compared with both LN and LL controls. Thymectomy did not alter the urinary excretion of adrenal steroids in LN and LL rats. The urinary excretion of B was markedly enhanced in thymectomized LH rats whereas that of DOC remained unmodified. 4. These data suggested that the thymus could be involved in the development of hypertension in LH rats. 5. The antihypertensive effect of thymectomy did not seem to be mediated by a decreased mineralocorticoid production in the genetically hypertensive rat of the Lyon strain.

Aldosterone↗
PubMed1976

Thymectomy for myasthenia gravis.

A group of 71 patients with myasthenia gravis is reviewed. All were initially managed medically, and 18 underwent thymectomy. Twenty-three responded poorly to drug treatment, and seven died from respiratory failure. In contrast, thymectomy was beneficial in 16 of the 18 who were subjected to operation. Seven patients had significant postoperative respiratory complications, and nine required a tracheostomy. Thymectomy appears to be effective and safe and to be indicated in young patients with early disease, and in patients who do not respond to drug treatment. The transcervical approach to thymectomy was satisfactory on two occasions.

Adolescent↗
PubMed2004

Associated conditions in myasthenia gravis: response to thymectomy.

To compare the response of thymectomy in patients with associated conditions (PWAC) and without associated conditions (PWOAC). Comparative, retrospective. 198 patients with the established diagnosis of myasthenia gravis who had a thymectomy between 1987 and 2000, and who were folowed up for at least 3 years. We formed two groups, one with associated conditions and the second without associated conditions. The patients were divided into four groups: (i) patients in remission, (ii) patients with improvement, (iii) patients without changes, and (iv) patients whose condition worsened. Associated conditions (AC) were found in 49 patients (26%). The main associated conditions were hyperthyroidism in 16 patients (33%) hypothyroidism in seven (14%), rheumatoid arthritis in five (10%) and hypothyroidism and Sjogren syndrome in three (6%). Concerning the response of thymectomy, 13 patients WAC showed remission (27%), vs. 54 patients WOAC (39%). Twenty patients WAC showed improvement (41%) vs. 46 WOAC (33%). Thirteen patients WAC had no changes (27%) vs. 37 WOAC (26%). Finally, in three patients WAC their condition worsened (6%) vs. three WOAC (2%). The response to thymectomy was high (69%) in both groups. We did not identify significant differences.

Adult↗
PubMed2005

Inhibition of IL-6 overproduction by steroid treatment before transsternal thymectomy for myasthenia gravis: does it help stabilize perioperative condition?

Overproduction of interleukin (IL)-6 plays an important role in the pathophysiology of myasthenia gravis (MG), and thymectomy can cause myasthenic crisis because of surgically induced overproduction of IL-6. Preoperative steroid therapy is beneficial in preventing MG crisis during the perioperative period. The purpose of this study was to clarify the effect of preoperative steroid therapy on proinflammatory mediators during the perioperative period of transsternal thymectomy for MG. The study group comprised 20 consecutive MG patients undergoing transsternal thymectomy during the period March 2002 through March 2004. Seventeen of these patients received dose-escalated steroid therapy before thymectomy (steroid treatment group) and three did not (non-steroid treatment group). Serum concentrations of C-reactive protein (CRP) and IL-6 were determined during the perioperative period; clinical outcomes were reviewed, and the results were compared between the two groups. Peak serum IL-6 and CRP concentrations were significantly lower in the steroid treatment group than in the non-steroid treatment group. Amongst perioperative variables subjected to multiple regression analysis, preoperative steroid treatment were found to be the most significant independent predictor of inhibited IL-6 production on postoperative day 1. No postoperative respiratory failure occurred in the steroid treatment group, but it did occur in the non-steroid treatment group. Preoperative steroid therapy can ameliorate IL-6 overproduction and may help stabilize the patient's postoperative condition.

Aged↗
PubMed1992

Remission rate after thymectomy in myasthenia gravis when the bias of immunosuppressive therapy is eliminated.

The clinical course of all 86 myasthenia gravis (MG) patients who were thymectomized at Sahlgrenska Hospital between 1955 and 1980 was evaluated in order to estimate what the rate of complete clinical remission (with or without anticholinesterase medication) would be without immunosuppressive (IS) therapy; 19 of 73 patients without thymoma received IS therapy. A suitable way of dissociating the course after thymectomy from the influence of IS therapy is the Markov method. The calculated probability of remission was 0.18, 0.35, 0.43, 0.53 and 0.56 in the 0-1, 2-3, 4-5, 5-10 and more than 10-year periods after thymectomy. A similar result (53 +/- 7%) was obtained by a life-table method with censoring of IS-treated patients when they received such therapy. Time to remission was significantly shorter for patients with age of MG onset before 35 years. Timing of IS therapy after thymectomy is discussed, considering the post-thymectomy remission rate.

Adult↗
PubMed1998

Thymectomy for myasthenia gravis.

The pathophysiological role of the thymus in myasthenia gravis, and the mechanism of therapeutic effect of thymectomy, are incompletely understood. Nevertheless, thymectomy is a valuable treatment modality in selected patients with generalised myasthenia gravis. There are several types of thymectomy operation, but no one operative approach is clearly superior to the others. Total removal of the thymus gland is essential. Additional excision of associated mediastinal and cervical tissue, that may harbor ectopic thymic rests, is a controversial surgical issue. Surgeons that advocate thymectomy through small, cosmetically favourable, incisions usually believe that simple removal of the thymus gland is an adequate operation. Surgeons that emphasise the importance of removing extrathymic tissue, in addition to the thymus gland, usually favour greater operative exposure through a median sternotomy. To minimise operative morbidity, surgery for myasthenia gravis requires a multidisciplinary (neurology, surgery, anaesthesia) approach to peri-operative care.

Humans↗
PubMed2003

Thymectomy in nonthymoma early-onset myasthenia gravis in correlation with disease severity and muscle autoantibodies.

OBJECTIVE: To study the clinical effect of thymectomy in a well-defined early-onset MG subgroup and to correlate it to MG severity, the presence of circulating muscle autoantibodies, and the need for pharmacological treatment in a long-term setting. METHODS: Fifty-two consecutive AChR antibody-positive early-onset MG patients (34 thymectomized and 18 nonthymectomized) were included. Severity was assessed and the pharmacological treatment monitored on a yearly basis, starting from the year of MG onset, for 5, 10, 15, and 20 consecutive years; AChR, titin, and RyR antibodies were assayed. RESULTS: In the four follow-up groups, MG severity was significantly higher in nonthymectomized compared to thymectomized MG patients. The postthymectomy MG improvement was significant and persistent. There were 21/34 remissions in thymectomized patients and only 4/18 in the nonthymectomized group. Patients with initially high or low AChR antibody concentration had a similar thymectomy outcome. Only 6 patients had titin antibodies, and none had RyR antibodies. CONCLUSION: The present study indicates a benefit of thymectomy in early-onset MG. The muscle autoantibody concentration does not influence the outcome of thymectomy in early-onset MG.

Acetylcholine↗
PubMed1978

Relationships between IgE antibody production and other immune responses. II. Effect of thymectomy at various times after birth.

Mice were subjected to thymectomy at various times after birth and immunized with ovalbumin in aluminum hydroxide gel at 4 or 8 weeks of age. The capacities to produce IgE, IgM and IgG antibodies were abolished by thymectomy carried out within 48 h after birth. The capacity to produce IgE antibody was not affected by thymectomy at 7 days or later, whereas the capacities to produce IgM and IgG antibodies were reduced by thymectomy carried out at 4 weeks of age.

Animals↗
PubMed2003

Thymectomy for myasthenia gravis: 12-year experience.

Thymectomy has been shown to be effective in the treatment of myasthenia gravis. The logical goal of operation is the complete removal of the thymus, but there is no consensus on the selection criteria of patients for surgery and the choice of surgical approach. We retrospectively reviewed 56 patients with myasthenia gravis who had been treated surgically by transsternal radical thymectomy between January 1990 and March 2002. The patients were symptomatically grouped according to the modified Osserman clinical classification. There was 1 hospital death, and 53 patients had been followed up for between 1 month and 12 years. Improvement after thymectomy was observed in 1 of 4 patients (25%) in Osserman group I, 25 of 34 patients (74%) in Osserman group IIA, and 16 of 18 patients (89%) in combined Osserman groups IIB and IIC. Transsternal radical thymectomy is an effective therapy for myasthenia gravis. Sustained improvement is achievable in female patients with moderate to severe symptoms and in patients with thymic hyperplasia.

Adolescent↗
PubMed2003

Development of a thymectomy trial in nonthymomatous myasthenia gravis patients receiving immunosuppressive therapy.

Thymectomy has been regularly used in the management of nonthymomatous autoimmune myasthenia gravis (MG), but its benefits have not been established in a randomized, controlled trial. The widespread use of thymectomy in MG patients without thymoma is largely based on retrospective, nonrandomized case series that have produced a consensus that the procedure is sometimes beneficial. Still, the benefits and utilization of thymectomy are actively debated among MG experts. In this paper, we describe the development of a multicenter, international trial to determine whether extended transsternal thymectomy reduces corticosteroid requirements for patients with generalized AChR antibody-positive nonthymomatous MG.

Adolescent↗
PubMed2003

Thymectomy and antimuscle antibodies in nonthymomatous myasthenia gravis.

The clinical effect of thymectomy in early- and late-onset myasthenia gravis (MG) and the correlation to MG severity, pharmacological treatment, and antimuscle antibodies were examined in two series of consecutive acetylcholine receptor (AChR) antibody-positive nonthymoma MG patients. The results indicate a benefit of thymectomy in early-onset MG, but no obvious clinical benefit in late-onset MG. The presence of muscle autoantibodies did not influence the outcome of thymectomy in early-onset MG. In late-onset MG, improvement is least likely in patients with titin and/or RyR antibodies. Thymectomy should always be considered shortly after MG onset in early-onset MG patients and might only be considered in late-onset patients who have early-onset-like immunological characteristics.

Adult↗