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Biomedical subjects

M Behrend

Publications and source records attributed to M Behrend.

At least 19 recordsLinked to original sources
PubMed2006

Indications and results of surgery for incidentally found adrenal tumors.

INTRODUCTION: The accidental discovery of an adrenal mass called incidentaloma has become an increasingly frequent clinical problem with the question of a correct and appropriate therapeutic approach being the subject of controversial discussions. MATERIALS AND METHODS: Clinical charts of 52 patients (22 male, 30 female) who underwent adrenalectomy for an incidentaloma at our institution between 1987 and 2001 were reviewed. RESULTS: Median age was 56.4 years. Reasons for surgery were unclear significance in 22 patients, suspicion of malignancy in 5, increase in size in 8, maximum tumor diameter of more than 5 cm in 7, fear of malignancy in 1, and subclinical secretion of cortisol in 5 patients. No data were available for 4 patients. Surgical resection was performed using a conventional transabdominal approach in 28 patients, a conventional dorsal approach in 17 patients, and an endoscopic retroperitoneal approach in 7 patients. Histopathologic examination ruled out adrenal adenoma in 32 patients, adrenal myelolipoma in 12, unilateral nodular hyperplasia in 4, cystic lesion in 3, and adrenocortical carcinoma in 1 patient. The mean size of all lesions was 5.5 cm. Evaluating the criteria for surgical treatment regarding age of the patients and size of the lesions, 25 patients (48%), including the patient with the adrenocortical carcinoma, were younger than 60 years and had an adrenal lesion exceeding 4 cm in size. During postoperative follow-up that was available for 39 patients, 3 developed contralateral tumors that were treated by resection in 1 and by close follow-up in 2. CONCLUSIONS: Size should not be the sole criterion; treatment should be tailored to the individual patient. Especially in patients younger than 60 years with an adrenal lesion exceeding 4 cm in size, an adrenalectomy, predominantly via an endoscopic approach, should be carried out, because a repeated and life-long close follow-up of an anxious patient who has been informed of the diagnosis will in some cases exceed the cost of a single endoscopic operation.

Adrenal Gland Neoplasms↗
PubMed2005

[Early results of proximal interphalangeal joint replacement with pyrolytic carbon prosthesis (Ascension) in idiopathic and post-traumatic arthritis].

Surgical treatment of painful idiopathic and post-traumatic arthritis with joint replacement of the proximal interphalangeal joint has become increasingly important. Due to shortcomings of former constrained and partially constrained prostheses with regard to abrasion and durability we have been using an unconstrained prosthesis since April 2002. This model is an almost abrasion free, biocompatible 2-component prosthesis. The surface is shaped like the condyles and the position is secured in a press-fit technique. During October 2004 we reviewed the results of 20 out of 29 patients with idiopathic or post-traumatic arthritis who had been treated with a pyrolytic carbon proximal interphalangeal joint prosthesis from April 2002 to April 2004 retrospectively. Clinical, subjective and radiological parameters were studied. On follow-up after 0.5 to 2.5 years the patients were satisfied with the pain relief. The range of motion varied. However, with an average ROM of 50 degree it was equivalent to the results in literature. Signs of periprosthetic cysts, osteophytes and loosening of the proximal as well as of the distal component could be seen in the radiograms of some patients. There was no correlation between these radiological observations and range of motion, pain or grip strength. In three cases the joint prosthesis had to be converted to an arthrodesis of the proximal interphalangeal joint. Bearing in mind the correct indications (intact collateral ligaments, stable bone stock and sufficient extensor and flexor tendons), pyrocarbon prosthesis are a treatment option for idiopathic and posttraumatic arthritis preserving motion and reducing pain. Radiological results seem to indicate an absence of osteointegration and tension forces at the prosthesis/bone interface. Further investigation will be necessary to improve surface and design to increase radiological results in long-term follow-up. Additional surveys are required to improve indications, surgical approach and intraoperative control of correct component positioning.

Adult↗
PubMed2004

[Resistance to pressure of bronchial closures. Comparison of pressure resistance of manual and stapler bronchial closures depending on the angle to the cartilaginous rings].

BACKGROUND: This study was aimed to determine the resistance to pressure of manual and stapled bronchial closures under ideal conditions (90 degrees to the bronchial tree) and parallel to the trachea (45 degrees). MATERIAL AND METHODS: An experimental study was done on 60 explanted pig tracheae which were alternatively closed with either double-layer, running sutures angled 90 degrees to the cartilaginous rings or an automatic stapling device. The closure line was placed exactly 90 degrees to the bronchial tree in 30 cases and parallel to the trachea (45 degrees) in 30. The sutures were placed under pressure until air leakage was observed. The leakage pressure was digitally recorded. RESULTS: A statistically significant difference existed between the two groups. Mechanical sutures proved more resistant to pressure (P=0.011). CONCLUSIONS: Under ideal conditions, the resistance to pressure of mechanical sutures is equal to if not better than that of manual sutures.

Animals↗
PubMed2004

Experience with the surgical treatment of adrenal cortical carcinoma.

UNLABELLED: We report on a series of 20 consecutive patients (10 males, 10 females) with adrenal cortical carcinoma (ACC) who were treated by surgery between 1987 and 2001. AIM: The aim of this study was to evaluate the outcome and the role of surgery in the management of this tumour. RESULT: One patient was at stage I, five patients at stage II, five patients at stage III and nine patients at stage IV of disease. Ten patients suffered from a functioning tumour, whilst ten patients revealed non-functioning tumours. In all patients a transabdominal approach was performed for the complete resection of the tumour, adjacent organs or metastases. The medium survival after surgical resection, calculated by the Kaplan-Meier method, was 45 months for the overall group, 65 months for patients at stage I or II, 38 months for patients at stage III and 19 months for patients at stage IV of disease. The 5-year survival rate for all patients was 23%, for patients at stage I or II 33%, for patients at stage III 20%, and for patients at stage IV around zero. CONCLUSION: Radical surgery with a complete resection of the tumour, adjacent organs, solitary metastases and loco-regional recurrence wherever possible improves survival, even at advanced stages of disease.

Adrenal Cortex Neoplasms↗
PubMed2002

Secretion of free and protein-bound leptin from subcutaneous adipose tissue of lean and obese women.

Leptin circulates as a free (FL) and a protein-bound (BL) form, with the soluble leptin receptor (LR) as an important binding compound. Here we measured these components of leptin in serum and in the incubation medium of sc adipose tissue in healthy lean (n = 10) and obese (n = 13) female subjects using recently developed specific RIA systems. In addition, immunostaining for FL, BL, and LR in adipose tissue was performed. Serum FL levels were increased in the obese subjects (P < 0.0001), whereas BL and LR concentrations in serum of lean and obese subjects were similar. Both FL and BL were secreted from human preadipocytes and increased in parallel to the differentiation of the cells. In sc fat cell explants LR antibodies predominantly stained the fat cell membrane, whereas FL and BL antibodies revealed intracytoplasmatic adipocyte staining. The release of FL, BL, and LR from adipose tissue was increased in obese compared with lean subjects (P < 0.005 for FL; P < 0.02 for BL, and P < 0.01 for LR). In summary, fat cells are capable of releasing not only FL, but also BL and LR.

Adipocytes↗
PubMed2001

[Spontaneous bleeding of focal nodular hyperplasia as a rare cause of acute abdomen].

Focal nodular hyperplasia (FNH) is a benign tumor of the liver. It is most frequently found in women of reproductive age. An association with oral contraceptives and sexual hormones is therefore possible. FNH lesions are frequently discovered incidentally. Spontaneous complications are rare. When the diagnosis is known with reasonable accuracy, a nonoperative approach is in common use. We report here the rare case of spontaneous intraabdominal bleeding from FNH.

Abdomen, Acute↗
PubMed2001

Tracheal reconstruction under tension: an experimental study in sheep.

AIMS: Invasion of the trachea by thyroid cancer is a difficult problem. Circumferential resection and end-to-end reconstruction is the treatment of choice. The objective of our study was to investigate the effect of tension on tracheal healing and stenosis formation, and to ascertain the maximum tolerable tension. METHODS: Tracheal resections of 3, 6 and 9 cm with end-to-end anastomosis were performed on 25 sheep. The intraoperative force required for approximation of the tracheal stumps was measured. Luminal stenosis was determined with the aid of computerized planimetry 1, 2, 4, 8 and 24 weeks post-operatively. RESULTS: A gradual increase of the stenosis rate occurred with increasing tension on the anastomosis. Acceptable results were achieved in the majority of cases without release techniques or tension suture. CONCLUSIONS: Tracheal anastomosis under tension does not always lead to disruption or separation of the anastomosis. With the additional use of release manoeuvres and tension sutures, tracheal anastomosis under tension are possible without severe stenosis. The additional use of temporary stenting needs to be elucidated.

Anastomosis, Surgical↗
PubMed2001

Adverse gastrointestinal effects of mycophenolate mofetil: aetiology, incidence and management.

Mycophenolate mofetil (MMF) is a relatively new immunosuppressive drug. It inhibits inosine monophosphate dehydrogenase, a key enzyme in the de novo pathway of purine synthesis, and thus causes lymphocyte-selective immunosuppression. Large clinical trials have revealed the efficacy of MMF in the prevention of allograft rejection when administered together with cyclosporin or tacrolimus and corticosteroids. Although the adverse effect profile of MMF is comparatively benign, gastrointestinal adverse effects are a major concern. These effects are partially explained by the increased immune suppression, by the mode of action and by interactions, particularly with other immunosuppressants. The aetiology of the rarest gastrointestinal adverse effects is still not completely clear. Therapy depends upon the clinical gravity of the adverse effects and is therefore a case of waiting and ob- serving. An adjustment of dosage of immunosuppressants according to the clinical situation and, particularly in the case of MMF, spreading the total dosage over more than 2 daily doses are often sufficient. Should adverse effects persist for a longer period of time and be of a more serious nature, a comprehensive invasive diagnostic process is necessary, including endoscopy and biopsy and the search for opportunistic infections. In this case, dosage reduction or the complete withdrawal of MMF seems to be unavoidable. Severe gastrointestinal complications with MMF are rare, but when they do occur they may require extensive diagnosis and treatment. In the future, therapeutic drug monitoring and, where necessary, pharmacological modifications of MMF could lead to a further reduction of adverse effects with an equal or even increased efficacy.

Adult↗
PubMed2001

Mycophenolate mofetil: suggested guidelines for use in kidney transplantation.

Mycophenolate mofetil (MMF) is an immunosuppressive drug designed to inhibit inosine monophosphate dehydrogenase (IMPDH). IMPDH is a key enzyme in the de novo purine synthesis of lymphocytes. It is crucially important for proliferative responses of human T and B lymphocytes. The inhibition of IMPDH thus leads to selective lymphocyte suppression. After successful use in various in vitro and animal models, MMF was brought to clinical trial in patients undergoing transplantation. The drug is rapidly and completely absorbed following oral administration. Pilot studies of administration with cyclosporin and corticosteroids suggested a significant reduction in the incidence of organ rejection at dosages of 1 to 3 g/day. As a result of these studies, 3 pivotal randomised double-blind multicentre trials, involving nearly 1500 patients, were designed to investigate the effects of addition of MMF to different standard immunosuppressive protocols on the prevention of acute renal allograft rejection. After 6 months, the rates of biopsy-proven rejection were significantly reduced in patients receiving MMF. In combination with cyclosporin and corticosteroids, the adverse effect profile resembled that of azathioprine. Most adverse effects were associated with the gastrointestinal tract, the blood system and opportunistic infections. MMF offers improved immunosuppressive therapy following renal and probably other solid organ transplantation. MMF has been licensed since 1995 for the prevention of acute renal allograft rejection in most countries. It has been used in different combinations of immunosuppressive drugs and in various dosages and regimens.

Animals↗
PubMed2000

Transplantation of H-2Kb-transgenic adrenocortical cells in the mouse having undergone an adrenalectomy: functional and morphological aspects.

BACKGROUND: A new model of cellular adrenocortical transplantation after bilateral adrenalectomy in the mouse was established. This model was used to study the effects of the expression of the transgenic MHC class I molecule H-2K(b) (Kb) on graft survival and morphologic features, corticosterone secretion, and the possibility of tolerance induction in the recipient. METHOD: A single cell suspension of purified adrenocortical cells was grafted under the kidney capsule of B10.Br (H-2k) mice having adrenalectomies. Syngeneic, fully MHC-mismatched, and MHC class I-incompatible Kb-transgenic mice served as donor strains. To analyze graft function, urinary excretion and serum levels of corticosterone were monitored over 100 days. Tolerance induction in the graft recipients of Kb-transgenic and third party skin grafts was tested on day 50 after adrenocortical transplantation. Histological sections of the adrenocortical grafts were obtained on day 100. RESULTS: Recipients of syngeneic and Kb-transgenic grafts displayed pretransplant corticosterone levels on days 20, 50, and 100 and ACTH-stimulated serum corticosterone levels similar to those of controls on day 100 after adrenocortical transplantation. In contrast, in recipients of fully MHC-mismatched grafts, corticosterone excretion was significantly reduced. In this group, 4 of 7 mice did not survive. Syngeneic skin grafts survived indefinitely in recipients of syngeneic and Kb-transgenic adrenocortical grafts, whereas Kb-transgenic and fully MHC-mismatched skin grafts were acutely rejected. Tissue sections of the adrenocortical grafts revealed vascularized cell conglomerates in syngeneic and Kb-transgenic grafts without infiltrations of mononuclear cells. Furthermore, a differentiation similar to adrenocortical organization was partly found. CONCLUSION: In conclusion, a model of cellular adrenocortical transplantation was established. The results show that syngeneic transplantation resulted in physiological corticosterone levels early after transplantation, whereas fully MHC-incompatible grafts were rejected. Recipients of Kb-transgenic grafts showed unimpaired adrenocortical function, but did not tolerize toward Kb-transgenic skin grafts. Possible mechanisms include a local immunomodulatory effect of glucocorticoids secreted by the graft and a low immunogenicity of the relatively small numbers of transplanted cells.

Adrenal Cortex↗
PubMed2000

[Development of obstructive jaundice after hemorrhage into a benign, non-parasitic liver cyst].

Benign, non-parasitic liver cysts are usually asymptomatic and found incidentally by abdominal ultrasound or CT scan. We present the case of a 68-year-old patient who showed obstructive jaundice due to a hemorrhagic liver cyst compressing the choledochal duct. Due to the location of the cyst in the porta hepatis with partial compression of central liver vessels and the meanwhile organized hematoma, operative therapy was preferred in order to prevent secondary complications such as portal vein thrombosis and to exclude a malignant neoplasm.

Aged↗
PubMed2000

Immune-adhesion molecules in the prevention of allograft rejection and reperfusion injury.

Control of the immune system is of indispensable importance for graft acceptance and function. Immunological changes in the graft before and after organ harvesting, the transplantation procedure itself and the organ recipients clinical state contribute to the immune response. Leukocyte trafficking [1] into a graft is regulated by various signal transducing molecules, which have been characterised during the past years. Ligand molecules on endothelial cells and in the organ parenchyma are the counterparts for leukocyte adhesion and tissue infiltration. The expression of these ligand molecules is regulated by soluble factors and cell-cell interactions [2]. The regulation of tissue inflammation and repair mechanisms involving components of the immune system therefore depends on a number of cell-surface interactions. The processes of intravascular adhesion, transmigration and infiltration by leukocytes and platelets are mainly mediated by receptor ligand interactions with target cells (cell-cell) and extracellular matrix proteins (cell-matrix). The main molecular families of adhesion receptor/ligand molecules have been identified. Today, we are still far from understanding this network of interactions. The numbers of molecules and factors involved are still increasing. This review summarises the currently available knowledge on the intervention in this system by monoclonal antibodies (mAbs), peptides and blocking agents. From this review, it is evident that further investigations are justified.

Animals↗
PubMed1999

Bednet impregnation for Chagas disease control: a new perspective.

BACKGROUND: To determine the efficacy and acceptability of deltamethrin-impregnated bednets in controlling Chagas disease in South America. METHODS: In three endemic departments of Colombia, a qualitative study on people's knowledge about Chagas disease, vectors, preventive measures and their willingness for collaboration in control operations was undertaken. Additionally, in an entomological study with 100 laboratory-bred Chagas vectors (Rhodnius prolixus), vectors were released for 5 nights (20 each night) in an experimental room, with the human bait protected for one night by an unimpregnated and for four nights by a deltamethrin-impregnated bednet (13 mg/m2). Vectors were stained with fluorescent powder for observation, collected after 10 h exposure in the experimental room and observed for a further 72 h. RESULTS: The study population did not know anything about Chagas disease, but believed the vector to transmit cutaneous leishmaniasis. Therefore willingness to take part in control operations was high. The experimental hut study showed a vector mortality rate of 95% in a room with impregnated nets and of 10% in a room with unimpregnated nets. CONCLUSION: This study opens a new perspective for Chagas disease control in integrated vector borne disease prevention programmes.

Animals↗
PubMed1999

Invasive differentiated thyroid carcinoma: tracheal resection and reconstruction procedures in the hands of the endocrine surgeon.

BACKGROUND: Although differentiated carcinoma of the thyroid gland is a relatively benign tumor, up to 20% of patients are endangered by potentially fatal complications resulting from infiltrating tumor growth into the upper aerodigestive tract. METHODS: This study included 33 patients who underwent 34 tracheal or laryngotracheal procedures for invasive differentiated thyroid carcinoma under the direction of a single surgeon (G.F.W.S.). From 1990 to 1994, radical tumor extirpation was performed by "window" resection, and from 1995 to 1998, radical surgery consisted of either circumferential sleeve resection or laryngotracheal "step" resection--a novel method of reconstruction in cases of unilateral tumor infiltration into the larynx and trachea. Resection was limited to laminar ablation in 17 cases. The mean follow-up of 16 patients who survived was 42.5 months (range, 2 months to 8.9 years). RESULTS: Procedures resulting in primary end-to-end anastomosis of the upper airways were associated with lower perioperative morbidity and improved recurrence-free survival when compared with "window" resections with muscle flap reconstruction. In cases of superficial tracheal tumor infiltration, laminar ablations were sufficient for local tumor control. CONCLUSIONS: Radical eradication of differentiated thyroid carcinoma infiltrating the upper airways followed by radioiodine application should be considered the treatment of choice. Laryngotracheal "step" resection allows tumor extirpation with preservation of neural and muscular structures of the larynx.

Adult↗
PubMed1999

The endothelin receptor antagonist TAK-044 in the treatment of reperfusion injury in organ transplantation.

Ischaemia and reperfusion are complex interrelated events that involve the vascular endothelium. The endothelium produces endothelin (ET), the most potent vasoconstrictor identified to date. During ischaemia, endothelial transcription of ET is increased, leading to strong and sustained vasoconstriction. Ischaemia and reperfusion are indispensable parts of solid organ transplantation. Various experimental data discussed in this review show an efficacy of the mixed ET(A/B) antagonist TAK-044 in the treatment of reperfusion injury. The overall safety and tolerability of TAK-044 in humans seems to be excellent. Large clinical randomised trials on the use of TAK-044 in the treatment of reperfusion injury in different clinical situations are missing, nevertheless, the future for ET antagonists is promising.

Journal Article↗
PubMed1998

Pronounced renal vasoconstriction and systemic hypertension in renal transplant patients treated with cyclosporin A versus FK 506.

This prospective study investigated hypertension and renal vasoconstriction developing during the 1st year after renal transplantation in patients randomly allocated to treatment with FK 506 (n = 28) or CyA (n = 13). Starting doses were 0.2-0.3 mg/kg per day for FK 506 and 5-8 mg/kg per day for CyA: doses were subsequently adjusted to trough levels (5-15 ng/ml for FK 506 and 100-150 ng/ml for CyA). We compared 24-h ambulatory blood pressure measurement, antihypertensive treatment, serum creatinine, and resistance index (RI), measured by Doppler ultrasound at the level of the interlobar artery. Until month 2 of treatment, FK 506-treated patients had a significantly lower RI (8%) and better renal graft function, as evidenced by significantly lower serum creatinine values. Some 13% of FK 506-treated patients, compared to 70% of CyA-treated patients (P < 0.01), needed additional antihypertensive drugs after transplantation to keep blood pressure stable. FK 506 treatment, at the above-mentioned dosages, was associated with a significantly higher number of infections (urinary tract infection, pyelonephritis, and pneumonia). We conclude that CyA produces greater renal vasoconstriction and systemic hypertension than FK 506, as reflected in higher renal interlobar artery RI values and a greater need for antihypertensive treatment. After 2 months of treatment and a reduction in CyA trough levels, the renal effects (i.e., lower RI and lower creatinine values), but not the systemic hypertensive effects, disappear.

Adult↗