Biomedical subjects

Matthias Behrend

Publications and source records attributed to Matthias Behrend.

At least 19 recordsLinked to original sources

PubMed2006

State of the art management of adrenal masses--"how to do it?".

By the frequent use of computed tomography or ultrasound the detection of incidentally found adrenal tumours has become a common problem. This is also reflected in the worldwide proliferation of literature over the past decades. Most incidentally-found adrenal tumours are benign non-functioning cortical adenomas. But benign functioning tumours producing aldosterone, cortisol or catecholamines, adrenocortical carcinoma or adrenal gland metastasis can also be found. Surgical therapy is always indicated in case of hormonal overproduction or in case of suspected adrenocortical carcinoma; in all other cases the correct and adequate therapeutic approach is still under debate and a controversial topic of discussion. This review deals with the different forms of adrenal tumours regarding the optimal diagnostic and therapeutic approach to give physicians an easy-to-follow guideline.

Adrenal Gland Neoplasms↗

PubMed2006

Basic immunosuppressive drugs outside solid organ transplantation.

Immunosuppressive drugs are the backbone of solid organ transplantation. The introduction of new immunosuppressive drugs led to improved patient and organ survival rates. Nowadays, acute rejection can be reduced to a minimum. Individualization and avoidance of drug-related adverse effects became a new goal to achieve. The potency of immunosuppressive drugs makes them attractive for use in various autoimmune diseases; therefore, the experience on immunosuppressive drugs outside the field of organ transplantation is analysed in this review.

Animals↗

PubMed2005

Surgical treatment of primary hyperparathyroidism.

BACKGROUND: With the use of routine calcium evaluation, the incidence of primary hyperparathyroidism (pHPT) has considerably increased. The aim of our study was the assessment of the morbidity and the outcome of surgically treated patients with pHPT. METHODS: The charts of 279 patients (204 female, 75 male, median age: 58 years) who underwent surgery for pHPT between 1989 and 1999 were retrospectively reviewed. A follow-up was carried out on 235 patients after a mean period of 3.6 years (0.2-10 years). RESULTS: In 148 patients a unilateral, and in 130 patients a bilateral approach was taken. Transplanted parathyroid tissue was removed from the left forearm of one patient. At follow-up persistent hypocalcemia was seen in 30 patients (20 after bilateral, 10 after unilateral exploration). 6 patients (1 after bilateral, 5 after unilateral exploration) revealed a newly developed persistent paresis of the recurrent laryngeal nerve. In 5 patients persistent (1 after unilateral, 4 after bilateral exploration) and in 5 patients recurrent (2 after unilateral, 3 after bilateral exploration) pHPT could be observed. CONCLUSION: Both unilateral and bilateral cervical exploration for pHPT have a high rate of success with a low morbidity. Therefore, patients with assumed asymptomatic pHPT with unspecific neuropsychological abnormalities should also be evaluated for surgical intervention.

Female↗

PubMed2005

Long-term follow-up after adrenalectomy for primary aldosteronism.

The objective of this study was to assess the long-term effects of adrenalectomy on the blood pressure and antihypertensive medication in patients with primary aldosteronism (PA). Twenty-four patients (15 female and 9 male) with a mean age of 48.3 +/- 10.8 years underwent surgery for PA in our institution between 1988 and 2001. All subjects were re-examined with a complete clinical work-up after a mean follow-up period of 86 +/- 48 months, including blood pressure readings (<140/90 mmHg defined as normal), endocrine adrenal function, and specific medication. All patients suffered from hypertension (onset 8.5 +/- 5.5 years prior to surgery). In 92% of the patients, hypokalemia was present (onset 2.0 +/- 2.6 years prior to surgery). The histopathologic examinations revealed unilateral adenomas in 23 patients and a bilateral hyperplasia in one patient. At follow-up, 33% (8) of the patients were completely cured (normal blood pressure and no antihypertensive treatment), with seven of these eight patients being under 50 years of age at the time of surgery. One patient revealed a contralateral aldosterone-secreting adrenal adenoma during the subsequent endocrine and imaging examination 44 months after the first operation. Despite normalized plasma-aldosterone concentration (PAC), plasma-renin-activity (PRA) and serum potassium levels, a long-lasting insufficiently treated hypertension due to the delayed diagnosis in patients with PA may explain the persistent blood pressure elevation, indicating the necessity of a life-long, regular control of the blood pressure and antihypertensive medication.

Adenoma↗

PubMed2005

Presentation and therapy of myelolipoma.

BACKGROUND: Adrenal myelolipoma is a rare and benign, hormonally inactive tumor frequently discovered incidentally. Because of the increasing rate of detection of adrenal myelolipoma, use of the correct diagnostic examination and treatment, with respect to surgical excision or regular controls, is continually gaining importance. We report herein on the largest series of surgically treated patients with adrenal myelolipoma from a single institute. METHODS: The clinical charts of 12 patients who underwent adrenal surgery for myelolipoma were reviewed. Follow up was carried out by means of re-examination or by personal contact with the primary physician. It was possible to perform a re-examination on eight of the 12 patients 6.9 years after the operation: one patient had died 5.2 years after surgery. RESULTS: Diagnosis of adrenal myelolipoma was made incidentally in seven patients, and during examination for reasons of unspecific abdominal or flank pain in five patients. A transabdominal approach was taken in five patients, a subcostal approach was taken in three patients and a translumbal approach was taken in four patients. At the follow up, all formerly symptomatic patients were free of symptoms. No recurrence could be seen; however, in one patient a contralateral adrenal myelolipoma had developed. CONCLUSIONS: Symptomatic tumors, growing tumors or tumors larger than 10 cm should be excised surgically by means of an endoscopic or conventional approach, depending on the size. Surgical indication should not be liberalized by the introduction of more gentle operative techniques such as the translumbal or the endoscopic approach. A close follow up should be maintained in the case of patients free of symptoms, and for those with a definite diagnosis from imaging procedures.

Adrenal Gland Neoplasms↗

PubMed2005

Enteric-coated mycophenolate sodium: tolerability profile compared with mycophenolate mofetil.

Mycophenolate mofetil is one of the most frequently used immunosuppressive drugs in solid organ transplantation. Although the adverse effect profile of mycophenolate mofetil is comparatively benign, gastrointestinal adverse effects are a major concern. The adverse effects may require a dose reduction or discontinuation, thus limiting its clinical efficacy. Enteric-coated (EC) mycophenolate sodium is a new formulation of mycophenolic acid (MPA) that delivers the active moiety MPA, the same active moiety delivered by mycophenolate mofetil. It has been developed to help protect the upper gastrointestinal tract. It is implied that a reduction of adverse drug effects as well as a reduction of dose may improve efficacy and compliance. Noncompliance is often underestimated in solid organ transplant recipients, and adverse drug effects increase medication nonadherence. Recent clinical trials comparing EC mycophenolate sodium and mycophenolate mofetil in kidney recipients reported similar rates of efficacy and adverse effects. It is noteworthy that systemic MPA exposure is higher with EC mycophenolate sodium than with mycophenolate mofetil, without increased gastrointestinal toxicity. This finding is quite surprising, because part of MPA-associated gastrointestinal toxicity is related to its antiproliferative effect on enterocytes. However, enteric coating of MPA did not markedly reduce the number of gastrointestinal adverse effects. Further studies focusing on dosage, therapeutic drug monitoring and immunosuppressive regimens may reveal benefits of EC mycophenolate sodium for optimal individualised immunosuppression and improved compliance. At present, EC mycophenolate sodium is an alternative immunosuppressant to mycophenolate mofetil in kidney transplant recipients with an almost identical efficacy and safety profile.

Biological Availability↗

PubMed2004

Cushing's syndrome: adrenalectomy and long-term results.

BACKGROUND: The objective of this study was to assess the preoperative symptoms, intra- and postoperative complications and follow-up in patients after uni- or bilateral adrenalectomy due to Cushing's syndrome (CS), independent of etiology. METHODS: Clinical charts of 42 patients (5 with ACTH-dependent, 37 with ACTH-independent CS) were reviewed, and follow-up data were obtained from re-examination of the patients. RESULTS: The symptoms most frequently seen were hypertension, changes of the skin and obesity. Eight bilateral and 36 unilateral adrenalectomies were carried out without any intraoperative complications. Postoperative complications occurred in 5 patients, 1 patient died on the fourth postoperative day. After a mean duration of 4.6 years 28 of 41 patients could be re-examined, 5 patients had died. One patient showed recurrence 4.3 years after unilateral adrenalectomy due to nodular hyperplasia, contralateral adrenalectomy again revealed nodular hyperplasia. CONCLUSION: Early diagnosis is essential in order to decrease the rate of pre-, intra- and postoperative complications. Endoscopic approach should be taken in a specialized center due to poor patient's condition. Recurrent disease on the contralateral side may represent bilateral adrenal hyperplasia with sequential tumor formation, demonstrating the importance of extensive preoperative biochemical and imaging testing and close follow-up.

Adenoma↗

PubMed2004

Prognostic value of cytotoxic T-lymphocytes and CD40 in biopsies with early renal allograft rejection.

After renal transplantation, different immunological and non-immunological factors lead to long-term allograft deterioration. Acute rejection episodes are one risk factor for chronic renal allograft dysfunction (CRAD). Following the current Banff classification the histological grade in acute rejection episodes is of limited prognostic value, therefore, additional morphological surrogate markers would be helpful. We investigated the biopsies of 91 patients with early acute rejection episodes for the immunohistochemical expression of key molecules (perforin, granzyme B, TIA-1, CD40) in the T cell-mediated rejection process. Staining results were correlated to long-term allograft outcome. Patients with greater than 2% of granzyme B or greater than 25% of CD40-positive cells in the interstitial infiltrate showed significantly shorter allograft survival. Patients with a CD40-positive vascular rejection or greater than 2% of granzyme B-positive cells in the interstitial infiltrate were significantly correlated with an earlier onset of CRAD. Our findings provide potential morphological surrogate markers in biopsies with early acute rejection episodes after renal transplantation. These could become part of combined clinical and histological algorithms, allowing patient-specific risk estimation and customized therapy options to be made.

Acute Disease↗

PubMed2004

Bilateral endoscopic adrenalectomy for Cushing's syndrome in a patient with polycystic liver and kidney disease.

Microadenomectomy via a transsphenoidal approach is today's treatment of choice to achieve normal cortisol blood levels in patients with ACTH-secreting pituitary tumors. Should neurosurgery fail, bilateral adrenalectomy is recommended. Today the endoscopic, transabdominal or retroperitoneal adrenalectomy is regarded as the gold standard for the operation of endocrine-active adrenal tumors. Therefore, in principle, the question of the indication for the endoscopic operation no longer arises but only the question of the technical feasibility in individual cases. We report on a patient with a pituitary-dependent Cushing's syndrome after a twice-repeated unsuccessful transsphenoidal adenomectomy and with additional polycystic kidney and liver disease, who underwent bilateral retroperitoneoscopic adrenalectomy. Despite the massive enlargement of both kidneys, it was possible to safely perform a bilateral retroperitoneoscopic adrenalectomy. In the case of marked bilateral cystic kidneys, a bilateral retroperitoneoscopic adrenalectomy in Cushing's syndrome is technical possible and a safe and effective method of treatment.

Adenoma↗

PubMed2003

Benign retroperitoneal schwannoma mimicking an adrenal mass.

Adrenal tumors are frequently incidental discoveries, and the therapy for them is the subject of controversial discussions. We report herein on such an incidentaloma, which proved to be a benign retroperitoneal schwannoma. A 48-year-old female with an unclear adrenal mass underwent retroperitoneoscopic tumor extirpation. A well-defined tumor that displaced the adrenal gland and adhered firmly to only one retroperitoneal nerve was discovered. The en bloc resection was performed without problem. The histopathologic examination revealed a benign schwannoma. Retroperitoneal schwannomas can mimic a multitude of different conditions. Because imaging methods frequently do not yield distinct results, quite often only the operative exploration can establish a definitive diagnosis. In a case of unclear retroperitoneal findings, an endoscopic extirpation should be considered.

Adrenal Gland Neoplasms↗

PubMed2002

Late embolization of an unfractured port catheter into the heart: report of a case.

This case report describes the embolization of an unfractured venous port catheter, 18 months after its implantation into the heart. To our knowledge, this complication has never been documented before. A 33-year-old woman underwent placement of a totally implantable venous access port for chemotherapy to treat advanced gastric cancer. The catheter tip was repositioned by a transfemoral sling after dislocation into the right jugular vein 2 months before embolization. After embolization into the heart, the catheter was successfully removed by a percutaneous femoral vein approach using a dormia basket. As totally implantable venous access ports become used more frequently, problems associated with their extended use will be encountered.

Adult↗

PubMed2002

Failure of airway healing in an ovine autotransplantation model that includes basic fibroblast growth factor.

OBJECTIVE: Basic fibroblast growth factor is among the most potent promoters of angiogenesis. Its ability to enhance the blood supply to ischemic airways or nonvascularized tracheal autograft has been demonstrated. Its cumulative effect with muscular wrapping and its efficacy in a noncanine large animal model remain unknown. Treatment with basic fibroblast growth factor and muscular wrapping were compared with no special treatment and with muscular wrapping alone in an ovine tracheal autotransplantation model. METHODS: All sheep underwent orthotopic tracheal transplantation with 5 to 8 ring autografts in the cervical trachea. Fifteen sheep were classified randomly into the following three groups: no treatment (group A, n = 5), muscular wrapping with the right sternomastoid muscle (group B, n = 5), and topical administration of fibrin glue enriched with 2 microg/cm(2) basic fibroblast growth factor (group C, n = 5). RESULTS: Devascularized tracheal autografts were unable to maintain their structural integrity without other treatment (group A). However, the grafts were surrounded by well-vascularized connective tissue. In the muscular wrapping group (group B), infections occurred around the grafts, and the muscular wrapping was subject to necrosis. No neovascularization of the grafts occurred. Therapy with basic fibroblast growth factor (group C) led to improved muscular wrapping circulation and to adherence to the tracheal stumps. However, no success was achieved in validating the circulation in the grafts. CONCLUSIONS: In contrast to the results achieved by other authors with canine models, the neovascularization of tracheal autografts was not achieved in sheep with the topical administration of basic fibroblast growth factor. Cranially pediculated muscular wrapping led to poorer circulation in the tissue around the graft than did no therapy at all.

Anastomosis, Surgical↗

PubMed2002

25 years experience of the surgical treatment of phaeochromocytoma.

OBJECTIVE: To assess the outcome of the surgical treatment of patients who had adrenalectomy for phaeochromocytoma. DESIGN: Retrospective clinical study. SETTINGS: University hospital, Germany. SUBJECTS: 87 consecutive patients with phaeochromocytoma who were operated on. INTERVENTIONS: 29 flank and 58 transabdominal adrenalectomies between 1974 and 2000. RESULTS: The mean tumour diameter was 5 cm (range 2-13), and the mean weight 91 g (range 7-550). The postoperative hospital stay was 11 days. The flank incision entailed the shortest operating time (95 minutes). Two of the phaeochromocytomas were malignant. There were two wound infections but no deaths. With a correct selection of patients, a flank incision is safe. Endoscopic retroperitoneal adrenalectomies should be preferred.

Adolescent↗

PubMed2002

A comparison of interrupted and continuous sutures for tracheal anastomoses in sheep.

OBJECTIVE: To study the tensile strength of tracheal anastomoses. DESIGN: Experimental study. SETTING: University medical school laboratory, Germany. ANIMALS: 15 sheep. INTERVENTIONS: Tracheal anastomoses with three different suturing techniques: a continuous suture and interrupted sutures with either a monofilament or a polyfilament material. Anastomoses were tested to breaking after being in place for 1, 2, 4, 8 or 24 weeks. RESULTS: After one week, with all three materials, the trachea broke at the anastomosis. In animals that survived longer, the trachea broke further away from the anastomosis. There was no significant difference between the mean values of the breaking force for continuous sutures and single interrupted sutures (p = 0.9). CONCLUSION: The suturing technique (continuous or interrupted) has less relevance for the tensile strength of the anastomosis than in vitro experiments suggest.

Anastomosis, Surgical↗

PubMed2002

The mechanical stability under load of tracheal anastomoses after various phases in vivo.

OBJECTIVE: The objective of our study was to postoperatively examine the mechanical stability under load of tracheal anastomoses over different periods in time and to compare these with native tracheae. STUDY DESIGN: A randomized experimental study on animals. METHOD: We performed tracheal anastomoses on sheep with three different suturing techniques and different resection lengths (3, 6, and 9 cm): These anastomoses were subjected to a breaking test at different intervals in vivo (1, 2, 4, 8, and 24 wk) and compared with the tracheae of healthy sheep. RESULTS: After 1 week in vivo, the anastomosis itself tore off from the remaining trachea under tension, regardless of the suturing technique used and the length of resection. With all animals that survived for a longer period, the trachea broke a greater distance away from the anastomosis. The necessary breaking forces were only minimally lower than those required for breaking healthy tracheae and the difference is statistically insignificant. When all operated tracheae are combined and the forces compared with native tracheae, this reveals that the operated tracheae are significantly more stable (P =.015) and present a lower longitudinal elasticity (P =.004). CONCLUSION: During the first postoperative days, the stability under load of tracheal anastomoses is slightly lower than that of healthy trachea. This difference is, however, far from those values that can be measured intraoperatively on tracheal anastomoses. Thus, supplementary measures for the mechanical protection against suture line separation do not seem necessary.

Anastomosis, Surgical↗

PubMed2002

The sheep as an experimental animal for tracheal surgery.

Resection and end-to-end anastomosis of the trachea are the preferred treatments for various benign and malignant diseases involving the trachea. Various suture techniques and suture materials have been reported; however, some basic questions are still unsolved. Most basic work has been done in dogs, but they are expensive to acquire and keep. Therefore, we evaluated the sheep as an experimental animal for tracheal surgery. We report on our results with sheep regarding anaesthesia, surgical procedure, and tracheal cross-sectional area. Sheep proved to be excellent experimental animals for surgical research regarding tracheal resections and end-to-end anastomosis.

Anastomosis, Surgical↗

PubMedDate not supplied

The mechanical influence of tissue engineering techniques on tracheal strength: an experimental study on sheep trachea.

Tissue engineering is an attractive concept for facilitating the transplantation of different tissue types with a low immunogeneity and a well-preserved tissue structure. We examined the influence of treatment with trypsin/ethylenediamine tetraacetic acid (EDTA) on the mechanical properties of tracheae. Fresh sheep tracheae were stored in a trypsin/EDTA solution for various periods of time (24, 46, and 72 h) and their breaking strength was subsequently examined. The results were compared with native trachea. The treatment with trypsin/EDTA results in a considerable reduction of the mechanical stability under load, in this case compared with the tensile strength, that does not correlate with the results obtained from light-optical microscopy. The results from this study reveal that tissue preparation with trypsin/EDTA does not seem to be a suitable method of preparatory treatment of tracheae intended for transplantation.

Animals↗

PubMedDate not supplied

A comparison of bronchial closure with the aid of staples or suture: an experimental study on pig tracheae.

The objective of this study was to determine the resistance to pressure of a bronchial stump depending upon the closure technique. For the experimental study, 30 pig tracheae were alternatively closed either by a double-layer running suture at 90 degrees to the cartilaginous rings or with an automatic stapling device. Sutures were placed under pressure until air leakage was observed. The air leakage pressure was digitally recorded. A statistically significant difference existed between the two groups. The mechanical suture proved more resistant to pressure (p =.011). Thus, under ideal conditions, the resistance to pressure of a mechanical suture is equal to, if not better than, that of the manual suture.

Air↗