Successful treatment of focal epilepsy by fractionated stereotactic radiotherapy.
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Adult↗
Biomedical subjects
M Buchfelder
Publications and source records attributed to M Buchfelder.
[Aquaretic drugs--a new therapeutic principle in treatment of hyponatremia?].
The antidiuretic hormone (vasopressin) is involved, either directly or indirectly, in the pathogenesis of almost all forms of hyponatremia. This means that blockage of the ADH effect at the renal ADH receptor represents a rational approach in the treatment of hyponatremia, in particular in difficult-to-treat and symptomatic forms. Recently, orally absorbable, non-peptidergic competitive ADH antagonists (aquaretics) have been introduced, which bind with high affinity to renal ADH receptor subtypes. Initial investigations in humans show that the substance is well tolerated. Numerous studies on patients with hyponatremia of varying genesis have since been started. It is to be expected that the availability of this new dass of substances will result in marked improvements in the treatment of acute and chronic forms of hyponatremia.
Antidiuretic Hormone Receptor Antagonists↗
Multiple intracranial lipoma: a case report.
We report on a male epileptic patient, presently 27 years old, who has suffered complex-partial attacks for 19 years. Under treatment with carbamazepine the seizures were completely controlled. In addition, the patient exhibited partial hypopituitarism. CT and MRI revealed the presence of 2 lipomas, one located within the optico-chiasmatic cistern and the other one in the medial temporal lobe. To our knowledge, this combination of the generally rare lesions has not been described yet.
Adult↗
Relationship between invasiveness of pituitary somatotrophinomas and structural abnormalities of protein kinase C gene in human.
The potential role of the protein kinase C (PKC) transduction system in controlling proliferation of human pituitary somatotrophinomas was investigated. Twenty somatotrophinomas were studied using PCR and direct sequencing methods. No point mutation within the alpha PKC gene, previously thought to be associated with invasive pituitary tumors, was found in any of the 20 somatotrophinomas. It is concluded that PKC transduction system may play an important role in controlling pituitary somatotrophinoma proliferation, but there is no correlation between invasiveness and the previously reported alpha PKC gene mutation.
Adenoma↗
[Long-term results of pituitary irradiation in Cushing's disease].
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Adenoma↗
Lymphocytic and granulomatous hypophysitis: experience with nine cases.
OBJECTIVE: Lymphocytic hypophysitis and granulomatous hypophysitis are rarely encountered. The aim of this study was to demonstrate their clinical peculiarities among pituitary disorders and to provide an approach for their clinical management. METHODS: In a retrospective study, we reviewed our surgical experience with nine patients harboring hypophysitis. The series included six cases of lymphocytic hypophysitis, two cases of granulomatous hypophysitis, and one case with evidence of coexisting lymphocytic and granulomatous hypophysitis. RESULTS: A striking similarity of clinical signs was found for our nine patients. Headache or aseptic meningitis, thickening of the sphenoid sinus mucosa, pituitary stalk enlargement, and tongue-shaped extension of the lesion along the basal hypothalamus were characteristic signs. Lymphocytic hypophysitis was not associated with pregnancy in any of the seven cases. No recurrence has been observed in six cases with total removal of the inflammatory tissue. CONCLUSION: Lymphocytic hypophysitis and granulomatous hypophysitis represent related inflammatory disorders. Their conspicuous clinical features frequently allow preoperative diagnosis of hypophysitis. In view of their sometimes insidious clinical course, early surgical exploration is justified.
Adolescent↗
Evidence supporting surgery as treatment of choice for acromegaly.
Within a period of fourteen years 531 operations for growth hormone (GH)-secreting adenomas were carried out. In this consecutive series 73% of the 396 patients who underwent primary transsphenoidal surgery achieved basal GH levels below 5 micrograms/l, and 58% also had an adequate suppression following an oral glucose tolerance test (OGTT). Slightly less favourable results were found in patients requiring surgery following an initial therapy. However, 41% of 121 such patients, who had either been operated upon previously or who had received external or internal irradiation, nevertheless achieved basal GH levels below 5 micrograms/l after the surgical reintervention. Normal suppression of serum GH during an OGTT was observed in 23% of these patients. The overall complication rate was low and tumour recurrences were very rare. To facilitate easier tumour removal, octreotide was preoperatively administered in 53 patients undergoing primary surgery of large adenomas. Recurrences were documented in a few exceptional cases. These data support our previous experience that once a normal suppression of growth hormone has been documented following surgery of pituitary adenomas, the long-term outcome is favourable.
Acromegaly↗
Molecular biology of growth-hormone-secreting human pituitary tumours: biochemical consequences and potential clinical significance.
Molecular biological studies have revealed that 30-40% of GH-secreting human pituitary tumours, associated with acromegaly, harbour single-base missense mutations within the Gs alpha gene, termed gsp oncogenes. In addition, a large proportion of GH-secreting tumours inappropriately express the GH-releasing factor (GRF) gene. Gsp-oncogenes result in elevated adenylyl cyclase activity with consequent abnormally high cAMP production. In culture, GH-secreting tumours expressing gsp oncogenes respond more efficiently to the somatostatin analogue, octreotide (SMS), raising the possibility that acromegalics harbouring gsp-positive tumours may be those who optimally benefit from SMS therapy. Inappropriate expression of GRF may result in abnormal presence of a positive autocrine feedback loop, in which secreted GRF acts on the same cells to promote cellular proliferation and GH secretion. Blockade of GRF mRNA translation by means of anti-sense oligonucleotide approaches may prove to be of value in inhibiting tumour function.
Acromegaly↗
Proliferation parameters for pituitary adenomas.
In this review, the value of assessing proliferation parameters in surgically resected pituitary tumour tissue is analyzed. Histological examination of basal dura biopsies identifies invasive growth even when intraoperatively not apparent to the surgeon. Determination of DNA-polymerase activity, Ki-67 immunohistochemistry and DNA-flow-cytometry shows a clear difference in the proliferative potential of enclosed and invasive pituitary adenomas. Among the various endocrinologically differentiated groups ACTH-secreting adenomas associated with Nelson's syndrome and thyrotropinomas were the most rapidly proliferating. At present, however, our results reveal that the prognosis of an individual patient cannot be reliably predicted on the basis of such studies.
Adenoma↗
Acromegaly--the place of the neurosurgeon.
Over 12 years, we performed 498 operations for growth hormone (GH)-secreting pituitary adenomas (489 in acromegaly and nine for gigantism), with 479 by the trans-sphenoidal and 19 by the transcranial route. A consecutive series of 224 patients had an overall cure rate of 56%, with normalization in 71% when the criterion was only basal GH. Endocrine remission occurred in 72% of microadenomas, 50% of macroadenomas, and only 17% of giant adenomas. Seventy-three percent of the patients with preoperative GH levels less than 10 ng/mL were cured, but only 33% with GH greater than 100 ng/mL. Our cure rate for invasive adenomas was 38%. Surgical reexploration can lead to a 50% cure rate. Overall morbidity was low. Pretreatment of large adenomas with octreotide may soften them and facilitate their removal, and one third shrink. It also relieves the symptoms of acromegaly and improves the patient's general condition for surgery. Octreotide as first-line therapy is indicated in patients with risk factors for surgery, and it is becoming an alternative to radiotherapy after surgery. It is more potent than dopamine agonists in lowering GH levels. We recommend postoperative radiotherapy (+/- octreotide) if GH levels are fairly high after surgery or if the adenoma shows major invasiveness. Surgery is still the initial therapy of choice in acromegaly due to its high cure rate and low morbidity.
Acromegaly↗
Recovery from severe osteoporosis following cure from ectopic ACTH syndrome caused by an appendix carcinoid.
It is well established that endogenous overproduction of glucocorticoids may cause osteoporosis. However, knowledge about potential recovery of the skeleton after cessation of corticosteroid excess is limited. We describe a 34-year-old female patient and discuss the complex diagnostic workup that led to the rare diagnosis of carcinoid of the appendix as the cause of Cushing's syndrome. The patient experienced multiple spontaneous rip fractures, and at that time, the bone mineral density of the lumbar spine was 4.3 SD below values for age-matched healthy controls. After removal of the tumour, the patient completely recovered. Measurements at the lumbar spine showed an increase in area bone density of 79% equivalent to 4 SD over a subsequent 3-year observation period. This first case of documented bone mass recovery in a patient cured of ectopic ACTH syndrome suggests a potential for excellent reversibility of steroid-induced osteoporosis and should be considered in the management of such patients.
Adult↗
Pituitary adenylate cyclase-activating polypeptide directly stimulates LH and FSH secretion by human pituitary gonadotrophinomas.
The effect of pituitary adenylate cyclase-activating polypeptide (PACAP) on LH and FSH secretion by human pituitary gonadotrophinomas in cell culture was studied. PACAP (1-38 peptide, 0.2-20 nmol/L) dose-dependently stimulated both LH and FSH secretion after 24 hours incubation. Of 11 tumours studied, PACAP (20 nmol/L) stimulated LH and/or FSH secretion by 1.7-4 fold in 9 cases. Two tumours did not respond to PACAP, although LHRH was stimulatory in these. None of the 11 tumours contained gsp mutations, excluding the possibility that these were the cause of the occassionally observed non-responsiveness to PACAP. A combination of PACAP (20 nmol/L) together with TRH (25 nmol/L) resulted in greater stimulatory effects on LH and FSH secretion than exerted by either peptide alone, but this was not observed with LHRH. In 3 tumours tested, PACAP stimulated cAMP production 2-3 fold by cultured human pituitary gonadotrophinomas but had no effect on rate of phosphatidylinositol (PI) turnover. These results indicate that PACAP can directly stimulate LH and FSH secretion by human pituitary gonadotrophs and that PACAP-receptors in gonadotrophin-secreting tumours are coupled with adenylate cyclase but not the PI second messenger system. We conclude that PACAP may play a role in controlling gonadotroph function in the human pituitary gland.
Adult↗
Serum leptin levels following hypothalamic surgery.
To study a potential alteration of hypothalamic centers involved in the negative feedback action of leptin on body weight, serum leptin levels were measured in relation to BMI in 18 patients following surgery for a hypothalamic craniopharyngioma (Ctx), and were compared to levels found in 21 patients operated for a pituitary adenoma (Ptx) or in healthy control subjects. All subjects with Ptx received rhGH replacement therapy (0.5 to 2 IU/m2/d), and serum leptin levels were followed in 3 months intervals over 24 months. Serum leptin levels in patients with Ptx were comparable to controls, whereas 7 of the 18 patients with Ctx had higher than expected concentrations for their BMI. GH treatment in Ptx subjects did not alter serum leptin levels. In 5 Ctx patients where preoperative samples were available, weight gain in parallel to an increase in serum leptin levels was observed but only minimal changes in 4 others. Our data support the role of leptin as an important marker of body weight. The rapid increase in serum leptin levels observed in some Ctx subjects suggests that early postoperative measurement of serum leptin levels may help to identify patients at risk of weight gain following hypothalamic destruction.
Adenoma↗
Relationship between protein kinase C and adenylyl cyclase activity in the regulation of growth hormone secretion by human pituitary somatotrophinomas.
OBJECTIVE: To determine the potential role of protein kinase C (PKC) and its relationship to adenylyl cyclase activity in controlling growth hormone (GH) secretion by human pituitary somatotrophinomas. METHODS: Twenty-eight somatotrophinomas were placed into cell culture, and the in vitro effects of the PKC activator 12-O-tetradecanoylphorbol 13-acetate (TPA) and the PKC inhibitor staurosporine on basal and GH-releasing hormone (GHRH)-stimulated GH secretion were examined. In addition, the influence of chronic exposure of cultured somatotrophinoma cells to TPA on the rate of inositol 1,4,5-trisphosphate production was determined. Each tumor was assessed for the presence of gsp oncogenes, and thus constitutive adenylyl cyclase activity, by direct sequence analysis of polymerase chain reaction-generated deoxyribonucleic acid. GH secretory responses of tumors with and without these oncogenes were compared. RESULTS: TPA consistently stimulated GH secretion by cultured somatotrophinoma cells. There was no difference in response between somatotrophinomas with and without gsp oncogenes, and the effects did not correlate with the variable stimulation exerted by GHRH. Tumors in which GHRH had no significant effect nevertheless responded to TPA. In combination, TPA and GHRH exerted additive stimulation. TPA treatment of cultured somatotrophinoma cells eventually resulted in suppression of inositol 1,4,5-trisphosphate production, probably reflecting down-regulation of membrane phosphatidylinositol hydrolysis, a second messenger system that also generates the endogenous PKC activator diacylglycerol. GHRH had no effect on phosphatidylinositol hydrolysis. In contrast to the effects of TPA, the PKC inhibitor staurosporine tended to reduce GH secretion, although this effect was not observed in all tumors examined. As with TPA, the effects of staurosporine did not correlate with presence or absence of gsp oncogenes. Furthermore, staurosporine did not reduce the stimulatory effects exerted by GHRH on GH secretion. CONCLUSION: These results demonstrate a role for the phosphatidylinositol-PKC second messenger cascade in controlling GH secretion by human pituitary somatotrophinomas. The results also show that the system operates relatively independent of intracellular adenylyl cyclase and, thus, protein kinase A.
Adenoma↗
Protein kinase C-dependent growth hormone releasing peptides stimulate cyclic adenosine 3',5'-monophosphate production by human pituitary somatotropinomas expressing gsp oncogenes: evidence for crosstalk between transduction pathways.
The effects of the synthetic GH-releasing peptides, GHRP-2 and GHRP-6, on phosphatidylinositol (PI) hydrolysis and cAMP production have been examined in human pituitary somatotropinomas with and without adenylyl cyclase-activating gsp oncogenes. Both peptides dose-dependently stimulated the rate of PI hydrolysis and GH secretion by cell cultures of both types of somatotropinoma. GHRP-2 was considerably more potent than GHRP-6. The effects on GH secretion were reduced or abolished by phloretin, an inhibitor of protein kinase C, and W7, an inhibitor of calmodulin. However, antagonism of the GHRH-receptor and of protein kinase A with (N-Ac-Tyr1,D-Arg2)GRF-(1-29)-NH2 and Rp-adenosine-3',5'-cyclic monophosphothioate, respectively, did not alter the stimulatory effects of GHRP-2 and GHRP-6 on GH secretion. The effect of GHRP-2 and/or GHRP-6 on cAMP production was studied in 15 tumors, seven of which possessed constitutive adenylyl cyclase activity as evidenced by presence of gsp oncogenes. Both peptides stimulated cAMP production in the latter but not former types of tumor. Moreover, GHRP-2 and GHRP-6 potentiated the stimulation of cAMP production induced by GHRH and pituitary adenylate cyclase-activating polypeptide in tumors without gsp oncogenes. These results demonstrate that GHRP-2 and GHRP-6 exert identical effects on human pituitary somatotropinomas, except for differences in potency. Additionally, under conditions of adenylyl cyclase activity above basal levels (i.e. through stimulation of G2-protein coupled receptors or because of gsp oncogene expression), cAMP production can be increased even further by GHRP, providing evidence for cross-talk between the PI and adenylyl cyclase transduction systems in pituitary cells.
Base Sequence↗
[Hormonally inactive hypophyseal adenomas: the results and late sequelae after surgery and radiotherapy].
PURPOSE: External radiation therapy for non functioning pituitary adenomas is clearly indicated in inoperable patients, after incomplete transsphenoidal microsurgery and in case of tumor progression. This retrospective analysis gives results and toxicity following surgery and postoperative radiotherapy of non-functioning pituitary adenomas. PATIENTS AND METHODS: Between 1983 and 1990, 50 patients with non-functioning pituitary adenomas received combined treatment at our institutions. Surgical approaches were transsphenoidal (61%), transcranial (24%) or a combination of both (15%) in short intervals. All 50 patients received a full-dose radiotherapy with single fractions between 1.9 and 2.1 Gy (median 1.9 Gy) and total doses between 46 and 63 Gy (median 48 Gy). Field sizes ranged between 20 and 72 cm2 (median 30 cm2). Endpoints of this study were: progression-free survival, late effects of brain, optic nerve and intracranial vessels, visual impairment and hypothalamic-pituitary dysfunction. Median follow-up was 54 months. RESULTS: Forty-seven of the 50 patients remained progression-free. Patients over age 60 years progressed more frequently (3/17) as compared to younger patients (0/33, p = 0.034). Following radiotherapy vision improved in 8 patients (16%), 14 patients (28%) experienced a visual impairment between 10% and 60% (according to the grading system of the German Ophthalmologic Society). In multivariate analysis no influence of age (p = 0.097) or biologically effective dose (BED) (p = 0.11) was seen on visual impairment. Three patients (6%) experienced late effects with optic neuropathy in 2 cases and temporal lobe necrosis in 1 case. Only the BED had a significant impact on late effects (p = 0.0094). Adrenal, thyroid and gonadal function abnormalities were present in 58%, 66% and 96% of the patients at last follow-up, respectively. CONCLUSIONS: Radiotherapy after incomplete transsphenoidal or transcranial surgery of non-functioning pituitary adenoma is an effective treatment. Future perspectives must include the better defining of high-risk patients and the reduction of late morbidity.
Adenoma↗
["Tailoring" resections in drug refractory temporal lobe epilepsy].
On the basis of results obtained from extensive pre- and intraoperative diagnostic investigations of 69 patients, minimalisation of epileptogenic brain tissue resection was strived for. The extent of resection ranged from selective amygdalohippocampectomy up to "en bloc" standard resections, and in rare cases even beyond these. In the majority of cases however, tailoring allowed smaller resections than the standard "en bloc" resections. The outcome of tailoring in regard to seizure control as well as verbal memory and visual performance show that this method should be favoured in epilepsy surgery of temporal lobe epilepsies.
Adolescent↗
The growth hormone secretagogue, L-692,429, induces phosphatidylinositol hydrolysis and hormone secretion by human pituitary tumors.
L-692,429 is a non-peptidyl GH secretagogue. We examined the effects of L-692,429 on cultured human pituitary tumors removed from patients with acromegaly. Dose-dependent stimulation of GH secretion was observed, with 1 mumol/L leading to 2 or 3-fold increases. Prolactin (PRL) secretion by a mixed somatotrophic-lactotrophic tumor was also stimulated. The effects of L-692,429 were abolished by phloretin and W7 but not Rp-cAMPS. Rate of phosphatidylinositol turnover was markedly increased up to 3-fold by L-692,429. These results show that L-692,429 increases hormone secretion by human pituitary cells via a protein kinase C and Ca2+ dependent mechanism.
Acromegaly↗