PubMed Health⌕ Search

Biomedical subjects

Markus Cybulla

Publications and source records attributed to Markus Cybulla.

10 recordsLinked to original sources
PubMed2006

Genetic and clinical investigation of pheochromocytoma: a 22-year experience, from Freiburg, Germany to international effort.

Although deceptively simple, the etio-pathogenesis of pheochromocytoma represents a clinical and molecular genetic investigative challenge. Here, we summarize, from a historical point of view, the 22-year-long studies initiated at the University of Freiburg, which developed from a local experience to a national and finally an international effort. All research activities are translational and clinical and hence, registry based and intended to improve the outcome of the patients, whether by improved detection, prevention, or treatment. Major clinical steps are the prospective study on hormone tests and imaging techniques for adrenal and extra-adrenal abdominal tumors as well as the concept of organ sparing and endoscopic tumor resection. Further, we introduced 18-fluoro-dopa positron emission tomography. Population-based registries were used in order to identify germline mutations in the susceptibility genes VHL, RET, SDHB, and SDHD in non-syndromic pheochromocytoma. We differentiated distinct clinical features of paraganglioma syndromes associated with SDHB and SDHD gene mutations. Finally, we identified predictors and prevalence of paraganglioma syndromes associated with mutations of the SDHC gene.

Adolescent↗
PubMed2005

Predictors and prevalence of paraganglioma syndrome associated with mutations of the SDHC gene.

CONTEXT: Paraganglioma syndrome includes inherited head and neck paragangliomas (HNPs) and adrenal or extra-adrenal pheochromocytomas and are classified according to the susceptibility genes SDHB, SDHC, and SDHD. In contrast with those with germline mutations of the SDHB and SDHD genes, clinical and genetic data on patients with mutations of SDHC are scarce. OBJECTIVE: To determine the prevalence and clinical characteristics of SDHC mutation carriers compared with patients with SDHB and SDHD mutations and with sporadic cases. DESIGN, SETTING, AND PATIENTS: Genetic screening for SDHC mutations in an international HNP registry of 121 unrelated index cases and in 371 sporadic cases from a pheochromocytoma registry, conducted January 1, 2001, until December 31, 2004. Identified index cases and affected relatives were clinically evaluated. MAIN OUTCOME MEASURES: Prevalence of and clinical findings for SDHC mutation-associated HNPs vs those with SDHB and SDHD mutations. RESULTS: The prevalence of SDHC carriers was 4% in HNP but 0% in pheochromocytoma index cases. None of the SDHC mutation carriers had signs of pheochromocytoma. We compared HNPs in 22 SDHC mutation carriers with the HNPs of SDHB (n = 15) and SDHD (n = 42) mutation carriers and with 90 patients with sporadic HNPs. Location, number of tumors, malignancy, and age were different: more carotid body tumors were found in SDHC (13/22 [59%]) than in sporadic HNPs (29/90 [32%], P = .03), as well as fewer instances of multiple tumors in SDHC (2/22) than in SDHD (24/42; P<.001), 0 malignant tumors in SDHC vs 6/15 in SDHB (P = .002), and younger age at diagnosis in SDHC than in sporadic HNPs (45 vs 52 years; P = .03). CONCLUSIONS: Patients with HNP, but not those with pheochromocytoma, harbor SDHC mutations in addition to those in SDHB and SDHD. In total, more than one quarter of HNP patients carry a mutation in 1 of these 3 genes. Head and neck paragangliomas associated with SDHC mutations are virtually exclusively benign and seldom multifocal. Analysis for germline mutations of SDHC is recommended in apparently sporadic HNP to identify risk of inheritance.

Adolescent↗
PubMed2005

Chronic renal failure and proteinuria in adulthood: Fabry disease predominantly affecting the kidneys.

The prognosis of Fabry disease has changed since enzyme-replacement treatment was introduced. Therefore, early diagnosis is instrumental. We describe a family presenting with chronic renal failure and proteinuria in which classic skin and neurological features were absent and the diagnosis of Fabry disease was difficult and not established until a second family member developed renal abnormalities. A 35-year-old man was admitted because he was overweight and had hypertension, with a serum creatinine level of 1.3 mg/dL (115 micromol/L) and protein excretion of 870 mg/d. Because 1 brother, who died years ago at the age of 32 years of acute myeloid leukemia, also had chronic renal failure and proteinuria, the diagnosis of Fabry disease was entertained. In the index patient, acroparesthesia, hypohidrosis, pain, angiokeratomas of the skin, and cornea verticillata suggesting Fabry disease were absent. Conversely, renal biopsy showed typical globotriaosylceramide deposits, and leukocyte alpha-galactosidase (alpha-GLA) A activity was decreased. Analysis of the alpha-GLA gene showed the mutation E66K. The mutation also was found in another asymptomatic 30-year-old brother who also had chronic renal failure and proteinuria, but normal extrarenal findings. In the brother who died, Fabry disease, missed at autopsy because of cancer-related findings, could be confirmed after repeated review of histological slides. Mutation carriers also included the mother, a sister (both without abnormalities), and a nephew (with episodic pains in his feet). We conclude that familial chronic renal failure combined with proteinuria is suggestive of Fabry disease, and such specific mutations as E66K predominantly may affect the kidneys.

Adult↗
PubMed2005

New genetic causes of pheochromocytoma: current concepts and the clinical relevance.

Pheochromocytoma and paraganglioma are tumors of the autonomous nervous system mainly occurring in the adrenal medulla, but also in the extraadrenal paraganglias of the abdomen, thorax, neck and skull basis. The etiology comprises germline mutations of now 6 genes. About 10 years known are the RET gene susceptible for multiple endocrine neoplasia type 2, the VHL gene for von Hippel-Lindau Disease, and the NF 1 gene for neurofibromatosis Recklinghausen (neuro- fibromatosis type 1). Since 2000 the genes for succinatedehydrogenase subunits SDHB, SDHC, and SDHD have been identified for paraganglioma syndromes type 4, type 3, and type 1 respectively. Investigations of series of pheochromocytoma patients identified germline mutations in one of the genes SDHB, SDHD, VHL and RET in 24% to 50% of the patients. Multifocal tumors, young age and positive family history, known features associated with inheritence, have not been present in all patients. Therefore, analyses of blood DNA for mutations in these genes are recommended. Positive tests provide the patients and their relatives with essential platforms for clinical care. Experiences in this field of medicine have shown that optimal management of patients with pheochromocytoma-associated syndromes is a high challenge. National registries may be instrumental in order to provide with adequate facilities.

Adrenal Gland Neoplasms↗
PubMed2004

When to look for Von Hippel-Lindau disease in gastroenteropancreatic neuroendocrine tumors?

Von Hippel-Lindau (VHL) disease is a progressive autosomal dominant multisystem disorder that is associated with a germ line mutation of the VHL gene on the short arm of chromosome 3. A variety of benign and malignant diseases, including eye and CNS hemangioblastomas, renal cell carcinoma and pheochromocytoma are the major components. Gastroenteropancreatic neuroendocrine tumors are also listed among the typical complications, although these occur seldom. Virtually all such tumors are pancreatic islet cell tumors. VHL-associated islet cell tumors are mostly hormone-inactive. They can be detected during screening investigations according to the multidisciplinary disorder or by workup of space-occupying lesions. There are no specific predictors for malignancy in VHL-associated islet cell neoplasias, but tumors smaller than 3 cm in diameter are believed to be always benign. Gadolinium-enhanced MRI is currently the imaging method of choice, but contrast-enhanced CT is also a diagnostic option. The spectrum of manifestations is illustrated by selected cases.

Adenoma, Islet Cell↗
PubMed2004

Renal toxicity after radionuclide therapy.

During the past 10 years, a variety of radiolabeled monoclonal antibodies, antibody fragments, and low-molecular- weight oncophilic peptides have been used to deliver radioactivity to target cells for therapeutic purposes. The high and persistent localization of several of these radiolabeled molecules in the kidneys raised concern about potential renal radiation toxicity compromising therapeutic effectiveness. In particular, radiolabeled peptides, such as yttrium-90-labeled synthetic somatostatin analogues, have initiated a discussion on the safety profiles of the various somatostatin derivatives in recent clinical trials. In general, the toxicity risk seems to depend on the characteristics of the oncophilic molecule, such as the molecular weight, electric charges and clearance pathways as well as the chemical and physical characteristics of the applied radionuclide. Encouraging results for the prevention of radiation-induced renal damage by radiolabeled peptides have been obtained by co-infusion of positively charged amino acids. The available literature on nephrotoxicity after radiolabeled peptide therapy is reviewed, and therapeutic options that have become available as a result of greater insights into putative pathogenic mechanisms are discussed.

Humans↗
PubMed2001

Effect of ibandronate on bone loss and renal function after kidney transplantation.

Severe osteoporosis frequently is observed after organ transplantation. In kidney transplantation, it adds to pre-existing renal bone disease and strategies to prevent osteoporosis are not established. Eighty kidney recipients were included in a randomized controlled prospective intervention trial. Treated patients (n = 40) received an injection of ibandronate, a bisphosphonate, immediately before and at 3, 6, and 9 mo after transplantation. The primary outcome measured was the change in bone mineral density. Secondary measures included graft outcome, spinal deformities, fracture rate, body height, and hormonal and metabolic data. Loss of spongy and cortical bone after transplantation was prevented by ibandronate. Changes of bone mineral density (ibandronate versus controls) were as follows: lumbar spine, -0.9 +/- 6.1% versus -6.5 +/- 5.4% (P < 0.0001); femoral neck, +0.5 +/- 5.2% versus -7.7 +/- 6.5% (P < 0.0001); and midfemoral shaft, +2.7 +/- 12.2% versus -4.0 +/- 10.9% (P = 0.024). Fewer spinal deformities developed with ibandronate (7 patients with 7 deformities versus 12 patients with 23 deformities; P = 0.047). Loss of body height was 0.5 +/- 1.0 cm versus 1.1 +/- 1.0 cm in control subjects (P = 0.040). Two bone fractures occurred in each group. There were fewer acute rejection episodes with ibandronate (11 versus 22; P = 0.009). Graft function after 1 yr was comparable. Bone loss, spinal deformation, and loss of body height during the first year after kidney transplantation are prevented by injection of ibandronate at intervals of 3 mo. The smaller number of rejection episodes of the ibandronate-treated group should be confirmed and its mechanism should be explored in additional studies.

Adult↗