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K Voigt

Publications and source records attributed to K Voigt.

At least 19 recordsLinked to original sources
PubMed1992

Characterisation of the expression and post-translational processing of the preprotachykinin-I gene and the regulated release of tachykinins by the RINm5F cell-line.

Normal transcription and postranslational processing of the preprotachykinin (PPT)-I gene and regulated release of substance P and neurokinin A by the rat pancreatic endocrine cell-line, RINm5F, has been demonstrated, using radioimmunoassays (RIAs), reversed-phase (rp)HPLC and Northern blot analysis. This is the first stable cell-line found to express the PPT-I gene and provides an opportunity for investigating PPT-I gene expression and tachykinin biosynthesis. RIN5mF cells are a model for the pancreatic beta-cell, which is not known to exhibit PPT-I gene expression which may, therefore, be a feature of the transformed state of these cells. These data may imply that the tachykinins are important in pancreatic islet embryogenesis.

Animals↗
PubMed1992

MR imaging of experimental meningeal melanomatosis in nude rats.

MR imaging of the rat brain has become an increasingly frequently used method in experimental neuroradiology. On a generally available 1.5 T whole body tomograph, supplemented with an individually made small coil and a special SE sequence we obtained fairly fine images of the structures of the rat brain. With gadolinium-DTPA, we were able to visualize posterior fossa and cervical leptomeningeal growth of intrathecally injected B16 melanoma in nude rats. Using MRI to follow experimental leptomeningeal metastasis, may provide a new means for diagnostic evaluation and preclinical testing of treatment modalities.

Animals↗
PubMed1992

Hemodynamic responses to noxious stimuli in brain-dead organ donors.

The case report presents evidence for the spinal origin of the marked hypertensive responses to noxious stimuli that may occur in organ donors who fulfill the commonly accepted criteria of brain death. Cardiovascular spinal reflex activity does not invalidate these criteria. For the first time, the catecholamine plasma concentrations have been determined during spinal pressor reflex activity. Circulating epinephrine increased more markedly than norepinephrine in both cases, rising to 4.7 and 44 times the baseline concentration respectively. The relation between plasma norepinephrine and epinephrine suggests involvement of the adrenal medulla in the reflex arc. The literature on spinal hemodynamic reflexes is reviewed.

Adult↗
PubMed1992

Acute endocrine failure after brain death?

After brain death, 32 potential organ donors were studied to determine serum and plasma concentrations of hypothalamic-pituitary hormones, thyroid hormones, and cortisol over a period of up to 80 hr. Diagnosis of brain death was established either on the basis of clinical criteria (n = 16) or by angiography (n = 16). While 78% of the organ donors developed diabetes insipidus, none of the circulating hormones of the anterior pituitary gland showed a progressive decline in concentration according to their plasma half-lives. With the exception of arginine vasopressin (AVP), no hormone concentration was found to be subnormal due to the onset of brain death. The subnormal free triiodothyronine (FT3) values in 62% of cases (median FT3 of 2.2 pmol/L within the first 24 hr) and the cortisol concentration of 6.9 micrograms/dl correlate with the frequency of similar findings in patients with severe head injuries. While the adrenocorticotropic hormone (ACTH) concentrations of 10-53 pg/ml remained constant during the study period, thyroid-stimulating hormone (TSH) and human growth hormone (hGH) concentrations showed a 12- and 35-fold increase from baseline values after 30-40 hr. These results suggest that, despite the now generally accepted criteria of brain death, there is still some residual function, and thus also perfusion of the hypothalamic-pituitary neuroendocrine system. This residual function appears to be sufficient to maintain hormonal plasma levels at least in the low reference range in most donors. Hormonal depletion in organ donors subsequent to brain death, as suggested repeatedly in the literature, could not be confirmed. The analysis of serum or plasma concentration patterns of a number of hormonal parameters following brain death does not support the rationale for a routine replacement therapy of total triiodothyronine (TT3) or cortisol to maintain endocrine homeostasis prior to organ harvest. However, dexamethasone therapy may be followed by suppression of the adrenal cortex of the organ donor. In these cases, cortisol substitution may be indicated.

Adrenocorticotropic Hormone↗
PubMed1992

Effective suppression of luteinizing hormone and testosterone by single doses of the new gonadotropin-releasing hormone antagonist cetrorelix (SB-75) in normal men.

In rats and nonhuman primates the new GnRH antagonist cetrorelix (SB-75; [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Pal(3)3,D-Cit6,D-Ala10]GnR H) has been shown to suppress testosterone secretion effectively and persistently. A clinical phase I study was performed to assess the hormonal effects of this highly potent antagonist in normal men. After 2 control examinations 30 young male volunteers were randomly assigned to 6 treatment groups (n = 5/group), and single doses of 0 (placebo), 0.25, 0.5, 1.0, 2.0, and 5.0 mg cetrorelix were administered sc. Blood samples were obtained over the course of 7 days postinjection. After maximal cetrorelix serum levels were achieved 1 h postinjection, the GnRH antagonist serum levels decreased with a terminal t1/2 of 29.8 +/- 4.2 h (mean +/- SE). LH secretion was suppressed dose- and time-dependently; maximal suppression occurred 4-6 h postinjection. Suppression of FSH did not reach statistical significance. Doses of 1.0, 2.0, and 5.0 mg cetrorelix significantly suppressed testosterone secretion compared to that in the placebo group. After the administration of 1.0 mg cetrorelix, maximal suppression was seen 8 h after injection, with testosterone levels of 7.5 +/- 1.1 nmol/L compared to 15.8 +/- 2.2 nmol/L in the placebo group. Maximal testosterone suppression by 2.0 and 5.0 mg cetrorelix occurred 12 h after injection, with testosterone concentrations of 4.9 +/- 0.5 and 2.2 +/- 0.4 nmol/L, respectively, compared to 16.5 +/- 1.7 nmol/L in the placebo group. Twenty-four hours after the injection of 1.0 and 2.0 mg cetrorelix, testosterone values were no longer significantly different from those in the placebo group, whereas in the 5.0-mg dose group testosterone concentrations increased slightly and reached serum concentrations in the lower normal range after 48 h. The only side-effect observed after the administration of cetrorelix was a transient local erythema at the injection site that disappeared within 30 min. No local induration or pruritus, or any adverse systemic side-effect occurred in any volunteer. In conclusion, the new GnRH antagonist cetrorelix effectively decreases serum LH and testosterone concentrations in a dose- and time-dependent manner and, therefore, has potential for treatment of sex hormone-dependent diseases and male contraception.

Follicle Stimulating Hormone↗
PubMed1991

Different modulation of the perioperative stress hormone response under neurolept-anaesthesia or enflurane for cholecystectomy.

Two groups of 13 patients, randomly allocated to receive either enflurane or neurolept anaesthesia for cholecystectomy, were compared in their cardiovascular and neuroendocrine response to surgery and in the postoperative period. There were no significant differences in blood pressure or heart rate. Catecholamine values were higher under neurolept anaesthesia towards the end of surgery and postoperatively. Median values for adrenaline during suture of peritoneum were 342 pg/ml and 88 pg/ml, respectively, P less than 0.05. In contrast, ACTH and cortisol rose to higher levels in enflurane treated patients. At the end of surgery median ACTH values were 75 pg/ml in NLA patients and 322 pg/ml in enflurane patients (P less than 0.01). Vasopressin increments during surgery were similar under both regimens, while prolactin was higher following induction of neurolept anaesthesia. It is discussed whether the differences in stress hormone secretion patterns under either form of anaesthesia reflect different stress protective properties or direct pharmacological effects of certain anaesthetics. We conclude that the hormonal stress response to surgery is critically dependent on the type of anaesthesia and may be discordant in different hormonal systems.

Adrenocorticotropic Hormone↗
PubMed1979

[Techniques and results after embolization of meningiomas (author's transl)].

The different techniques and results are described for a total of 25 preoperative tumor embolizations in 21 patients with meningiomas of diverse localizations and extents. Transfemoral catheter techniques were superior to direct punctures of the carotid arteries because of the easier handling of the catheters, the better superselectivity of angiography, and, consequently, the more exact placement of the emboli. The results of the embolizations depended on the localization of the meningiomas. Meningiomas of the convexities (six patients) turned out to be particularly susceptible to complete embolizations. Satisfactory results were achieved operatively and histologically through embolization in meningiomas of the falx with large parasagittal expansion as well as in those of the lateral sphenoid wing, the sylvian fissure, and the cavum Meckeli (nine patients). Embolization of tumors which were localized exclusively at the falx, the tentorium, or of more medially situated meningiomas of the sphenoid wing were without beneficial effect, since these are predominantly vascularized by branches of the internal carotid arteries. Provided the localization and vascularization of a tumor are favourable the application of superselective angiography and preoperative embolization represents an important improvement of the basic conditions for a later operation.

Adult↗
PubMed1979

[The angiographic demonstration of infra-tentorial tumors with identical manifestations, localisation and histology in identical twins (author's transl)].

The angiographic diagnostic features of concordant tumors of the posterior fossa in monozygotic twins are described. In both cotwins cranio-spinal subependymomas were found which had grown through the foramen magnum and reached from the fourth ventricle down to the second cervical vertebra. Thereby, the conformity of the clinical mainifestation, symptomotology and the course of the disease, the localisation and extent of the tumors as well as the neuroradiologic findings and the histologic features of the tumors were particularly striking. After a review and critical summary of the few cases of concordant affections with brain tumors in identical twins published in the literature at present our couple is discussed under the question of the possible influence of genetic factors or a hereditary disposition on the development of cerebral tumors.

Adult↗
PubMed1979

[The neuro-radiological anatomy of the normal and abnormal rat brain. I. Radiological techniques for normal anatomy (author's transl)].

In vivo and post mortem techniques for the radiological examination of normal brains have been developed, using 66 white adult rats. Aortic arch injections for survey angiograms (10 animals), selective catheterisation of the internal carotid artery (16 animals) and ventriculography by percutaneous needle puncture (20 animals) were performed in vivo; the animals survived and the examinations could be repeated. The techniques proved useful and accurate methods for the radiological demonstration of the topography and morphology of cerebral vessels and chambers; they also provided information on the function of the cerebral circulation and C.S.F. dynamics. The findings were checked and correlated by post mortem studies (20 animals) using contact radiography, micro-angiography and casts of the ventricles. As a result, extensive topographic and anatomic information concerning the cerebral vessels in the rat was obtained, including some microscopic-radiological findings. The combined use of these methods provided a basis for studying the growth of experimentally induced brain tumours and the effect of various types of treatment.

Angiography↗
PubMed1979

[Cerebral angiography with ioglicinate (Rayvist). A double blind study of image quality and clinical side effects (author's transl)].

The image contrast quality and the patient tolerance of two osmotically active water-soluble contrast agents were examined and compared in double blind study cerebral angiography: Rayvist (an Ioglicinate developed recently) and Telebrix (AN Ioxithalamate). In 100 direct carotid or retrograde brachial angiograms the tolerance of Rayvist was significantly better, primarily because of less subjective patient side effects and less frequent cardiovascular reactions. However, there was no significant difference in neurological complications or deterioriation of EEG-findings, both quite rare anyway.

Adult↗
PubMed1978

[Neuroradiological diagnosis and treatment of dural carotid-cavernous sinus fistulae (author's transl)].

The neuroradiological diagnostic and therapeutic procedure in seven patients with nine dural fistulae between distal branches of the external carotid artery and the cavernous sinus is described. All patients had proptosis, signs of increased orbital venous pressure, and different degrees of pareses of the ocular muscles. During the diagnostic investigations selective angiographies of the internal and external carotid arteries and of the vertebral arteries were performed on both sides in order to exclude or to demonstrate branches of these vessels supplying the shunts. Subsequently those branches of the external carotid arteries feeding the fistulae were angiographied superselectively and embolized by repeated Gelfoam-injections during this same examination. Finally, the embolization of the shunts was proved by control angiographies in all cases. Following embolization, a pulse-synchronous bruit preexisting in four patients had disappeared. In all patients there was a complete remission of proptosis, signs of increased orbital venous pressure and blepharoedema within 2 weeks, and of the pareses of the ocular muscles within 4 to 6 weeks. After periodical control examinations at intervals of 4 to 6 weeks and during a period of 6 to 15 months none of the patients showed neurological deficits or signs of recurrence of the embolized fistulae. Superselective angiography and simultaneous embolization of dural carotid-cavernous sinus fistulae is therefore proposed as the current therapeutic procedure of choice for the treatment of these vascular malformations.

Adult↗
PubMed1978

[Long-term follow-up study of the absorption of gas after encephalography in dilated intracranial cerebrospinal fluid spaces (author's transl)].

The absorption of gas after encephalography in different groups of patients was investigated in a long-term follow-up study. Group I (11 patients) showed no pathological findings in the encephalogram. Group II (8 patients) had encephalographic signs of diffuse cerebral atrophy. Group III (7 patients) demonstrated in the encephalogram characteristics of normal pressure hydrocephalus with variously located blocks of air in the subarachnoid space. In group I the gas located in the subarachnoid space had usually disappeared after 24 h, in some cases after 72 h. In group II the pattern of resorption was basically similar, although in one case cortical air could be seen at 96 h. In group III the absorption of air from the subarachnoid space began after 72 h in radiological relevant amounts. In none of the cases of group III could similar short times of resorption be seen in comparison to group I. It is considered that these two groups can be clearly distinguished from each other in the duration of resorption of air from the subarachnoid space. The importance of encephalography as a pathophysiological tool for investigation of both the disturbed resorption and circulation of the cerebrospinal fluid in normal pressure hydrocephalus is stressed.

Absorption↗
PubMed1978

Prenatal neuroradiology: comparative radiological investigations of the embryonal and fetal brain.

In 400 embryos and fetuses of domestic animals and men, prenatal development of the cerebral vessels and ventricles was examined by postmortem arteriography, phlebography, microradiography, and ventriculography. In the ventricular system, qualitative and quantitative changes could be demonstrated and developmental diagrams of the growing ventricular spaces and angles were elaborated. The differentiation of the aortic arches into the major cranial arteries and the complex transformations of the cerebral venous system were documented by angiography within a period of gestation of 4 weeks up to term. Intrauterine angiography was also carried out in living fetuses of cats as preliminary studies of the development of cerebrovascular malformations.

Animals↗
PubMed1978

Angiographic, operative, and histologic findings after embolization of craniofacial angiomas.

After pre- or intraoperative angiography and Gelfoam embolization in patients with deforming vascular malformations in the craniofacial region, the angiographic findings and the results of embolization were controlled by operation and histology. In arteriovenous hemangiomas the disfigurations of the craniofacial region originate from the shunt vessels themselves, in capillary hemangiomas exclusively from neoplastic, pathologically dilated and convoluted veins which could be demonstrated only by percutaneous punctures. Lymphatic hemangiomas also could be radiologically shown only after direct punctures and without any feeding or draining vessels. During operation vast necrosis of the fatty tissue in the region of embolization and massive phlebolithiasis in the draining veins were found. Histologically, arterial obliterations could be shown in the former shunt area. The reconstructive operations could be done in bloodless surgical regions and always showed good cosmetic results, which were regarded as constant because of the embolization of the shunt area.

Adolescent↗
PubMed1978

Techniques and results of neuroradiologic investigations of experimentally induced brain tumors in rats.

In two comparable groups of 12 adult rats at a time, the normal anatomy of the cerebral arteries and the pathologic vascular pattern of experimentally induced brain tumors was investigated angiographically. These tumors were malignant mixed gliomas which were inoculated by percutaneous puncture through the vault with a suspension of 10,000 tumor cells. The neuroradiologic examinations consisted of selective angiographies of the internal carotid artery in vivo, postmortem radiographies of cerebrovascular casts of isolated brains as well as of microangiographic and comparative histologic investigations of the tumor. The juxtaventricular localization and the extension of the tumors in the basal ganglia could be angiographically demonstrated approximately 3 to 4 weeks after the implantation of the tumor cells. Moreover, qualitative and quantitative vascular criteria of malignancy could be shown microangiographically which correlated well with the histologic findings. The effects of several therapeutic procedures such as radiotherapy, pharmacoangiography and various techniques of embolization are being studied with this experimental tumor model in order to explore the prerequisites for appropriate treatment of cerebral lesions in man.

Animals↗
PubMed1978

Comparative microangiographic and histologic studies of the embryonal development of intracerebral capillaries.

In 69 embryos and fetuses of cattle and pigs with an age of gestation of 4 weeks to 4 months the development of intracerebral capillaries was studied comparatively by microangiography and controlled by histologic slices. The first invasion of blood vessels into the wall of the neural tube takes place in the brain stem and colliculus ganglionaris at an age of gestation of 4 weeks. After that, specific and different angioarchitectonic patterns of capillary development can be demonstrated within the telencephalon, basal ganglia, and brain stem. The telencephalic vessels show concentrically arranged areas of ramification which interrupt their longitudinal course towards the ventricular cavity. The branchings are related topographically to the projection fibers from the internal capsule and to the subependymal matrix layer. In the basal ganglia, the developing internal capsule interrupts the blood supply of the caudate nucleus from the periphery, and a new central system is established mainly running radially towards the ventricular canal. Thus, it could be shown in consecutive stages of cerebral development that the angioarchitectonic pattern of a certain embryonal stage and brain area depends on the histologic structure of the neural tissue and its specific metabolic demands.

Animals↗