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Biomedical subjects

M M Behrens

Publications and source records attributed to M M Behrens.

16 recordsLinked to original sources
PubMed1992

Paramedian thalamopeduncular infarction: clinical syndromes and magnetic resonance imaging.

We prospectively examined 11 patients with magnetic resonance imaging-documented infarction in the paramedian thalamopeduncular region, which is supplied by the superior mesencephalic and posterior thalamosubthalamic arteries. Variations in the size and rostral-caudal extent of infarction correlated with the following three clinical patterns: (1) With unilateral paramedian mesencephalic infarction, an ipsilateral third nerve paresis was accompanied by mild contralateral hemiparesis or hemiataxia. Contralateral ptosis and impaired upgaze were observed in two patients; one of them showed additional damage to the posterior commissure. (2) With bilateral infarction in the thalamopeduncular junction, involving the mesencephalic reticular formation, supranuclear vertical gaze defects were accompanied by impaired consciousness or memory, and mild aphasia in some patients. Persistent amnesia was observed only when the dominant anterior nucleus or mamillothalamic tract was damaged. (3) With larger thalamopeduncular infarcts, partial or complete third nerve paresis was combined with supranuclear gaze disturbance and delayed contralateral tremor. An unusual gaze disorder, a variant of the vertical "one-and-a-half syndrome," occurred with a small strategically placed lesion at the thalamopeduncular junction, best explained by selective damage to supranuclear pathways or partial nuclear involvement. The primary cause of these infarctions was embolism to the basilar apex or local atheroma at the origin of the posterior cerebral artery.

Adult↗
PubMed1991

The sleep test for myasthenia gravis. A safe alternative to Tensilon.

The diagnosis of myasthenia gravis is usually confirmed by a Tensilon test, which can be complicated by cholinergic side effects that include cardiopulmonary arrest. An alternative, the Sleep test, based on the characteristic of myasthenia that symptoms and signs worsen with fatigue and improve after a period of rest, is safe, moderately sensitive, and specific. The diagnosis of myasthenia can be confirmed by observing resolution of ptosis or ophthalmoparesis immediately after a 30-minute period of sleep; the reappearance of the myasthenic signs over the next 30 seconds to 5 minutes adds further confirmation.

Blepharoptosis↗
PubMed1989

cAMP- and RAS-independent nutritional regulation of plasma-membrane H+-ATPase activity in Saccharomyces cerevisiae.

The plasma-membrane ATPase of Saccharomyces cerevisiae is a proton pump whose activity, essential fro proliferation, is subject to regulation by nutritional signals. The previous finding that the CDC25 gene product is required for the glucose-induced H+-ATPase activation suggested that H+-ATPase activity is regulated by cAMP. Analysis of starvation-induced inactivation and glucose-induced activation of the H+-ATPase in mutants affected in activity of the RAS proteins, adenylyl cyclase or cAMP-dependent protein kinase showed that nutritional regulation of H+-ATPase activity does not depend directly on any of these factors. We conclude that adenlyl cyclase does not mediate all nutritional responses. This also indicates that the specific CDC25 requirement for the glucose-induced activation of the H+-ATPase identifies a new function for the CDC25 gene product, a function that appears to be independent of CDC25-mediated modulation of the RAS/adenylyl cyclase/cAMP pathway.

Cell Cycle Proteins↗
PubMed1989

Ocular pseudomyasthenia or ocular myasthenia 'plus': a warning to clinicians.

Myasthenia gravis (MG) commonly presents with weakness and fatigability of the lids and extraocular muscles, which respond to treatment with anticholinesterase medication. However, certain intracranial mass lesions may mimic these features of MG; alternatively, MG may mask the signs of a coexistent intracranial mass. We describe 8 patients originally diagnosed as having MG by knowledgeable clinicians, in whom an intracranial lesion instead of, or in addition to, MG was later identified. The lesions included parasellar tumors and aneurysms. In patients presenting with clinical features of ocular MG, it is therefore essential to establish a definite diagnosis of MG, to exclude other possible causes of "pseudomyasthenia," and to exclude other diseases that might be masked by coexisting myasthenic weakness. We recommend that patients with clinical features of MG limited to the ocular or cranial musculature be thoroughly evaluated for intracranial mass lesions, using CT or MRI if warranted.

Adolescent↗
PubMed1988

Yeast cAMP-dependent protein kinase can be associated to the plasma membrane.

Using an anti-yeast regulatory subunit antibody and the synthetic peptide Kemptide as specific substrate we show in this work that purified preparations of yeast plasma membrane have an associated form of the regulatory subunit and cAMP-dependent protein kinase activity. Treatment of the plasma membrane "in vitro" with 1 microM cAMP releases cAMP-independent protein kinase activity while regulatory subunit remains on the membrane as revealed by immunoblotting. Incubation of the plasma membrane with [gamma-32P]ATP results in the phosphorylation of the regulatory subunit.

Carrier Proteins↗
PubMed1979

Orbitofacial angiomatosis.

Two patients with orbital vascular malformation ipsilateral facial nevus flammeus were studied. The literature contains one similar case that interestingly shares with our cases the lack of leptomeningeal angiomatosis. Orbitofacial angiomatosis seems to be a distinct entity from meningofacial angiomatosis because of its true vascular malformation of the orbit.

Angiomatosis↗
PubMed1978

Nystagmus.

Explore the source record for details and available documents.

Adult↗
PubMed1977

"Release hallucinations" as the major symptom of posterior cerebral artery occlusion: a report of 2 cases.

Visual hallucinations were the presenting symptoms in 2 patients with probable infarcts in the territory of a posterior cerebral artery. They occurred in areas of paracentral scotomas, right in Patient 1 and left in Patient 2. In Patient 1 they were formed, prolonged, and not apparently related to past experience. In Patient 2 they were at first paroxysmal and unformed, with more prolonged metamorphopsia; later there appeared to be palinoptic formed images, possibly postictal in nature. Such hallucinations appear to be of a "release" type, and may be more common than is generally appreciated in patients with posterior cerebral artery occlusion.

Adult↗
PubMed1975

Moebius syndrome in Kallmann syndrome.

A girl born with congenital paresis of cranial nerves III, IV, and VII (Moeblus syndrome) subsequently developed a progressive peripheral neuropathy. There was suggestive evidence of a familial neuropathy with autosomal dominant inheritance in three family members. The patient also had hypogonadotrophic hypogonadism and anosmia (Kallmann syndrome).

Abducens Nerve↗
PubMed1975

Homonymous hemianopia in multiple sclerosis. With report of bilateral case.

A patient with multiple sclerosis and bilateral retrochiasmal visual field defects is reported. Homonymous field defects are rare in multiple sclerosis despite the frequency of pathological involvement of the retrochiasmal visual pathways. A higher incidence might be found with a higher index of suspicion and careful visual field testing with qualitative confrontation technique. Other reasons for the infrequent clinical detection of retrochiasmal lesions are considered. Such lesions may exist without demonstrable defect. This may be explained by anatomical factors, for example, fibre arrangement, or physiological factors, such as, geniculate or retrogeniculate integration. Lesions producing demonstrable defects may be asymptomatic because they: affect only the peripheral field, are small scotomas that do not impair visual acuity, affect only one eye, or occur late in the course of disease when masked by optic nerve involvement.

Adrenocorticotropic Hormone↗