Biomedical subjects

C H Meyer

Publications and source records attributed to C H Meyer.

90 records · Page 5Linked to original sources

PubMed1983

Progressive change in cerebral blood flow during the first three weeks after subarachnoid hemorrhage.

Cerebral blood flow (CBF) was estimated from each cerebral hemisphere by the 133Xe inhalation method. Daily estimates were made during the first 3 weeks after subarachnoid hemorrhage (1265 studies in 116 patients). Some of the patients were taking adrenergic blocking drugs (propranolol and phentolamine), others were taking tranexamic acid, and the rest were taking no drugs. CBF was also studied in 67 normal subjects. The resting CBF was related inversely to age not only for normal subjects but also for patients after subarachnoid hemorrhage (SAH). The CBF fell progressively during the first 2 weeks after SAH and was abnormally low throughout the 3 weeks after hemorrhage. For any 1 day after SAH, those patients who were fully alert had the smallest reduction in CBF. The progressive changes in CBF occurred whether or not an aneurysm was present on angiograms. For aneurysms situated to one side of the midline, the changes in CBF affected both sides of the brain. The progressive decline in CBF was least in those patients who subsequently made the best clinical recovery. Arterial pCO2 seemed to influence CBF throughout the 3 weeks after SAH. During the 2nd week, CBF was especially low in SAH patients treated with tranexamic acid. The serial changes in CBF are discussed in relation to current views concerning the timing of operation for ruptured aneurysms.

Adult↗

PubMed1982

Subarachnoid haemorrhage: older patients have low cerebral blood flow.

Daily estimations of hemispheral cerebral blood flow using the xenon-133 inhalation technique was made in 116 patients during the first three weeks after subarachnoid haemorrhage. The patients' cerebral perfusion on average remained less than the normal perfusion expected for their age (based on a single estimation of cerebral blood flow in 67 volunteers). On each separate day after subarachnoid haemorrhage cerebral blood flow was inversely related to the patient's age. Older patients seem especially at risk of developing cerebral ischaemia after subarachnoid haemorrhage. The clinical outcome was more often unfavourable in older patients--that is, in those who tended to have the lowest cerebral blood flow. Present results support the view that episodes of low cerebral blood flow lead to a poor outcome after subarachnoid haemorrhage. Because of the risk of inducing cerebral ischaemia great care should be exercised by physicians administering hypotensive drugs to older patients after subarachnoid haemorrhage.

Adult↗

PubMed1982

Cardiac sequelae of acute head injury.

An intensive 72 hour study of the cardiovascular effects of severe diffuse brain injury was made in seven patients. No other major injury was present. Patients received optimal care very rapidly after injury and intracranial pressure, which was continuously monitored, was maintained at or just above normal by elective positive pressure ventilation techniques. Three patients showed evidence of progressive myocardial ischaemia on continuous electrocardiographic monitoring. Two of these patients died. Ventricular arrhythmias were uncommon but one of the patients with ischaemia developed ventricular tachycardia. Heart rate patterns were very abnormal but did not predict complications. Blood pressure did not vary greatly and cardiac outputs were usually normal. Pronounced excesses of urinary catecholamines and serum creatine kinase 2 isoenzyme (CK MB) as well as total creatine kinase were found. Histological evidence of myocardial damage could be shown at necropsy in the one case whose heart was available for study. This study shows that the cardiac effects of isolated diffuse cerebral injury may be harmful and even fatal despite correction of secondary factors such as anoxia and raised intracranial pressure. The findings suggest that evaluation of the potential benefits of sympathetic blockade is warranted. Cardiac complications of cerebral damage deserve wider recognition by intensive care personnel, neurologists, and neurosurgeons.

Adolescent↗

PubMed1982

Akinesia in Parkinsonism. Relation between spontaneous movement (other than tremor) and voluntary movements made on command.

In eleven patients with Parkinsonism there was a strong inverse relationship between the frequency of spontaneous activity of the arms and the degree of fatiguing of repetitive finger movements made upon command. The prevalence of spontaneous arm movement was related inversely (but more weakly) to the time taken to complete a pegboard test or to move clothespegs by hand; it had little association with the speed of linear movement or with simple motor reaction time involving the arm.

Adult↗

PubMed1981

Bilateral improvement in voluntary movement after unilateral diencephalic lesions for parkinsonism.

In 14 patients with parkinsonism a unilateral ablation at the lower border of the ventrolateral thalamus relieved tremor and rigidity in the contralateral arm but not in the ipsilateral arm. Voluntary movement improved in both arms for three single-handed tasks, each involving the proximal and distal parts of the limb. For one task (a ballistic drawing movement) the postoperative change in one arm was correlated with that in the other arm. The lesion also improved repetitive voluntary movement of the fingers, but only in the contralateral hand.

Adult↗

PubMed1981

Cellolite (Merocel): a new form of neurosurgical patty. Evaluation of histological responses in rats.

Cellolite and cottonoid were compared with regard to histological reactions provoked when they were left in contact with the rat brain. Pieces of each material were implanted in 27 rats either extra- or intracerebrally for 48 hours or 28 days. Histological findings suggest that the use of Cellolite for neurosurgery would be unlikely to cause adverse reactions any worse than those caused by cottonoid.

Animals↗

PubMed1980

Parkinsonism: If surgery is necessary, can it help spontaneous movement and motor fatiguing?

Eleven patients with Parkinsonism had unilateral sterotaxic lesions made in the vicinity of the ventrolateral thalamus to reduce contralateral tremor and rigidity. The results indicate that a lesion of this sort allows motor fatiguing to improve in those limbs in which rigidity is reduced. It increases contraletral spontaneous movement if it relieves rigidity by a sufficient amount. Otherwise spontaneous movement is reduced. The lesion affects the spontaneous movement of the ipsilateral arm in parellel with its effect on the contralateral one.

Adult↗

PubMed1977

The microstructure of isotropic vapor-deposited carbon films.

The structure of thin, vapor-deposited carbon films was characterized by transmission electron microscopy and electron diffraction. Selected area electron diffraction showed very weak and broad peaks, indicating that these carbons contain extremely small crystallites whose dimension in the crystallographic c-direction is about 8 to 10 a. The observed diffraction bands are (h, k, 1 = 0) type reflections, which suggests that individual crystallites consist of graphitic layer planes stacked in parallel groups but with no order between atoms in adjacent planes (turbostratic). The carbon films exhibit no preferred orientation, indicating that the small crystallites are randomly oriented in the film and that the films are therefore isotropic. The measured density (1.8 g/cm3) and the structure of the vapor-deposited carbons are accordingly similar to those of low-temperature isotropic (LTI) pyrolytic carbons.

Carbon↗

PubMed1977

[Neuropathies following hand surgery under supraclavicular plexus anesthesia].

15 cases with pain in the shoulder girdle following an operation in supraclavicular brachial plexus anesthesia are reported. The pain developped after an interval of several days. According to the neurological findings the diagnosis is regarded as neuralgic amyotrophy. Possible causes are discussed.

Anesthesia, Conduction↗

PubMed1974