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H Tritthart

Publications and source records attributed to H Tritthart.

At least 19 recordsLinked to original sources
PubMed2000

IK.ACh activation by arachidonic acid occurs via a G-protein-independent pathway mediated by the GIRK1 subunit.

The molecular target of arachidonic-acid-derived metabolites, serving as second messengers that activate atrial acetylcholine-activated potassium current (IK.ACh) in addition to G-protein beta/gamma subunits (Gbeta/gamma), is unknown. Co-expression of two isoforms of G-protein-activated, inwardly rectifying potassium channels (GIRKs) in oocytes of Xenopus laevis revealed that these heterologous co-expressed GIRKs, which are responsible for the formation of IK.ACh in the atrium, are activated by arachidonic acid metabolites, like their counterparts in atrial cells. The expression of homooligomeric GIRK1(F137S) and GIRK4wt channels revealed that this activatory mechanism is specific to the GIRKI subunit. Sequestrating available Gbeta/gamma by overexpression of C-betaARK (a Gbeta/gamma binding protein) failed to abolish the activation of GIRK currents by arachidonic acid. From our experiments we conclude that the GIRKI subunit itself is the molecular target for regulation of GIRK channels by arachidonic acid metabolites.

Acetylcholine↗
PubMed1994

Sitting position for neurosurgery: experience with preoperative contrast echocardiography in 301 patients.

A persisting foramen ovale (PFO) is the most common cause of paradoxical air embolism. To detect right-to-left shunting, transthoracic contrast echocardiography was performed preoperatively in 301 patients scheduled for neurosurgical procedures in the sitting position. Echocardiography yielded evaluable results in 285 patients (94.7%). In 72 of 285 patients (25.2%), a PFO was diagnosed on the basis of contrast echo signals appearing in the left atrium or ventricle within 5 heart cycles after application of contrast medium via a peripheral vein. If echo signals appeared in the left heart after more than 5 heart cycles, an intrapulmonary right-to-left shunt was considered (11 patients, 3.9%). Venous air embolism (VAE) occurred in 27.4% of 226 patients operated on in the sitting position and in none of the 59 patients operated on in a nonsitting position. We conclude that the sitting position during neurosurgery should be avoided in patients with preoperative evidence of a right-to-left shunt at contrast echocardiography to reduce the risk of paradoxical air embolism (PAE).

Adolescent↗
PubMed1993

Primitive neuroectodermal tumor (PNET) extending into the cerebellopontine angle: case report.

The most common primary tumors of the cerebellopontine angle are growths of the 8th cranial nerve. The occurrence of other tumors in this area is very rare and may cause neuroradiological misinterpretation. We report the findings in a 37-year-old male patient suffering from a primitive neuroectodermal tumor (PNET) extending from the latero-basilar cerebellar hemisphere into the cerebellopontine angle (CPA) and causing cerebellar dysfunction as well as symptoms of typical cerebellopontine angle lesions. Differential diagnosis of tumors found in this area is given as well as a histological description of the tumor along with immunohistochemical findings and aspects of possible prognostic relevance.

Adult↗
PubMed1988

[Increase in intracranial pressure in monitoring brain stem auditory evoked potentials using headphones].

Ten measurements of intracranial pressure (ICP) (ventricular n = 5, epidural n = 3) in 8 patients (3 after aneurysm surgery, 5 with head trauma) were performed before and after application of conventional headphones for stimulating brainstem auditory evoked potentials (BAEP). The effects of miniature earphones and sound tubes on ICP were also studied. In 7 of 10 measurements after application of headphones a reversible increase of ICP (mean 26 +/- 19% in patients with ICP greater than 10 mmHg was recorded; in 3 patients (ICP less than or equal to 10 mgHg) no changes of ICP were seen. Using miniature earphones and sound tubes no increase of ICP was noted in any patient, and hence these can be recommended for stimulating BAEP in case of increased ICP.

Acoustic Stimulation↗
PubMed1981

[Intracranial germinoma; typical CT appearances and radiation therapy (author's transl)].

The typical CT appearances of intracranial germinomas are described in three cases. These consist of an isodense or hyperdense tumour in the mid-line, originating from the pineal body or infundibulum, with marked increase in density on contrast enhancement. Periventricular tumour expansion in relation to the entire supratentorial ventricular system is characteristic. The rapid tumour regression after small doses of radiation is stressed and complete regression of the tumour, as seen on CT, is a sign of its radio-curability.

Adolescent↗
PubMed1979

Shunt metastases in posterior fossa tumors.

Permanent (CSF-drainages for treatment of hydrocephalus in posterior fossa tumors have been used in the last few years, increasingly. The rare incidence of extracranial metastases and it's higher frequency in the same period of time has been remarkable. An additional case of metastasis via ventriculoperitoneal shunt is presented. Such deleterious complications of malignant CNS-tumors should be avoided, as progressively improving results with combined radio-chemotherapy have established a more encouraging prognosis.

Abdominal Neoplasms↗
PubMed1978

Azotaemia in severe head injury--central dysregulation or renal failure?

We have investigated serum urea, uric acid, and creatinin crealinine levels in 39 patients with craniocerebral trauma. The most impressive observation was a change in serum urea, which was found significantly increased up to 237 mg% on the seventh day (mean value) after severe injury, and turned out to be of great prognostic value. Patients with a serum urea above 100 mg% did not survive the acute stage. Uric acid and creatinine were only significantly increased in patients with lethal outcomes, the first being elevated by about 300% in the first week, the second remaining normal for four days increasing thereafter. It is concluded from these first data that a hypercatabolic state due to shock, central dysregulation, or both, is responsible for the dissociated behaviour of urea, uric acid and creatinine during the first four days, after which renal failure as a secondary change is shown by the rise in serum creatinine.

Brain↗
PubMed1978

[Extraneural metastasis of an oligodendroglioma in ventriculo-peritoneal shunt].

The clinical and pathological report presents a seven-week old girl suffering from signs of raised ICP. A ventriculo-atrial shunt was inserted and replaced by a ventriculo-abdominal shunt due to occlusion at 15 months of age. At 16 months, craniotomy and resection of an oligodendroglioma was performed and the shunt was preserved. The child died at 18 months due to extensive local recurrence. Autopsy revealed massive peritoneal metastases of the tumor. This is the eleventh published case of canalicular metastases of glioma.

Brain Neoplasms↗
PubMed1977

[External ventricular drainage--a new aspect in the operative treatment of head injury (author's transl)].

It is not only for CSF-removal in conservative treatment of oedema and control of the effectiveness of osmo-onco-therapy, contricosteroids, anticholinergics and aldosterone-antagonists, that external CSF drainage in severe cerebral trauma has proved of value. It has also made it possible to assess objectively the indications for bitemporal craniotomy in raised intracrainial pressure with an acute midbrain syndrome caused by tentorial herniation. Continuous monitoring of ICP permits an intervention at the right time and prevents one from operating too late, namely at a moment, when manifest neurological signs already indicate cerebral decompensaervative steps failing, a bitemporal craniectomy is indicated: in this way we lower intracranial pressure, liberate the rostral brain stem out of its strangulation and improve cerebral perfusion and metabolism.

Adolescent↗