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Biomedical subjects

A Harmsen

Publications and source records attributed to A Harmsen.

At least 37 records · Page 2Linked to original sources
PubMed1984

Serial measurement of regional cerebral blood flow in patients with SAH using 133Xe inhalation and emission computerized tomography.

A noninvasive three-dimensional method for measuring cerebral blood flow (CBF), xenon-133 inhalation and emission computerized tomography, was used to investigate the CBF changes accompanying delayed neurological deterioration following subarachnoid hemorrhage (SAH). A total of 67 measurements were performed on 20 patients in Hunt and Hess' clinical Grades I to III in the first 21 days post SAH. Five patients with normal CBF tomograms on admission developed delayed neurological deficits in the 2nd week after hemorrhage, at which time repeat CBF tomograms in four patients revealed large areas of well defined regional flow decrease in the vascular territories of the anterior or middle cerebral arteries. Severe vasospasm was noted in three of these patients in whom arteriography was performed in the 2nd week post SAH. Diffuse bihemispheric CBF decreases were noted later in the course of delayed neurological deficits; however, measurements obtained soon after the onset of focal symptoms suggest that the only CBF decreases directly produced by vasospasm in Grade III patients are regional changes.

Adult↗
PubMed1983

Controlled hypotension with sodium nitroprusside: effects on cerebral blood flow and cerebral venous blood gases in patients operated for cerebral aneurysms.

The effect on cerebral haemodynamics of arterial hypotension induced by sodium nitroprusside infusion was studied in nine patients at the end of operations for intracranial aneurysms under N2O-O2-halothane anaesthesia. Cerebral blood flow (CBF), using the intraarterial 133Xe injection method, and cerebral jugular venous blood gases were monitored before, during and after the induced hypotension. CBF and jugular venous oxygen tension (PvO2) remained constant during the hypotensive period. Following its termination, a 13% increase in CBF occurred (P less than 0.05) and PvO2 showed the same trend, a 5% increase (P less than 0.30). Regional CBF recordings (rCBF) in 16 small areas within the cerebral hemisphere were obtained at each measurement. In four of the patients, rCBF abnormalities were present in the form of hyperaemic regions, probably induced by the operation or the disease itself. The focal abnormalities were not accentuated during hypotension nor were ischaemic regions disclosed. It is concluded that sodium nitroprusside has only a minor influence on cerebral haemodynamics in the anaesthetized state.

Adolescent↗
PubMed1983

Cerebral abscess. A long-term follow-up.

During the period 1935-1976, 200 cases of brain abscess were treated in the University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. 119 patients survived. Out of 40 deaths during the follow-up period, 37 were unrelated to the previous brain abscess. 12 patients emigrated and were lost to follow-up. History and neurologic examination of the remaining 67 surviving patients with follow-up periods of between 3 and 40 years (mean 18 years) showed no sequelae in 23, unrestricted working capacity in 46, epilepsy in 37, neurologic deficit in 18, and intellectual impairment in 13 patients. The most serious sequelae, incapacitating epilepsy and severe mental reduction, were seen in patients with brain abscess during childhood.

Adolescent↗
PubMed1982

Cerebral abscess. Aetiology and pathogenesis, symptoms, diagnosis and treatment. A review of 200 cases from 1935-1976.

From 1935-1976 a total of 200 patients with cerebral abscesses were referred to the University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. The primary source of infection could be established in 169 cases (85%). Bacteria could be cultured in 58% of the cases. From 1935-1957 nearly all patients were subjected to ventriculography (107/129). Cerebral angiography was the dominating diagnostic method from 1958-1974. Since then, 30 patients with a suspected intracranial abscess have been examined by computed tomography. The overall mortality has been 40%, but for the period 1958-1976 17%.

Adolescent↗
PubMed1980

X-ray kinetic studies of microtubule assembly using synchrotron radiation.

The assembly of microtubules has been investigated by time-resolved X-ray diffraction using synchrotron radiation. The small-angle scattering becomes visible within seconds and thus enables study of the structural transitions of the protein aggregates during assembly from their subunits in solution. The X-ray pattern at 4 degrees C arises from a mixture of tubulin rings, dimers and some other species. Raising the temperature to 36 degrees C induces the breakdown of rings, followed by the growth of microtubules. The results suggest that microtubules may be formed from tubulin oligomers smaller than rings.

Animals↗
PubMed1980

Intracranial Saccular Aneurysms. Results of treatment in 851 patients.

The series studied comprises all 851 patients with symptom-producing intracranial saccular aneurysms admitted to the departments of neurosurgery in Denmark in the five-year period of 1970-1974. The series was divided into seven clinical stages according to Hunt's classification. More than half of the patients were grouped in stages IV and V (Hunt grade 2-3). Of the patients, 76% were found primarily suitable for operation. The mortality within the individual stages was to a great extent independent of the time of operation. A total of 94% of the aneurysms were localized within the region of the carotid artery, with a roughly equal distribution among the internal carotid, anterior communicating, and middle cerebral arteries. Multiple aneurysms were found in 19% of the patients subjected to panangiography. There was a distinct correlation between the severity of the spasms and the clinical condition. The course of operation was complicated in 49% of the patients, the complications being equally distributed within the various clinical stages. The mortality for the patients who underwent operation (total 567) was 32%, and 80% of the deaths were due to direct or indirect consequences of aneurysmal bleeding. At the follow-up performed two to seven years after operation, 52% of the survivors were fully capacitated, 20% were partly capacitated, and 28% were incapacitated. Based on a retrospective analysis, we have started a comprehensive prospective study with registration of available parameters in patients with saccular aneurysms admitted to all departments of neurosurgery in Denmark.

Adolescent↗
PubMed1978

Incidence and long term survival of children with intracranial tumours treated in Denmark 1935-1959.

The total number of children under 15 years of age with intracranial tumours in Denmark during the years 1935-1959 was found to be 533. The average incidence was 21 new cases/10(6) children/year during the 25-year period in question, and 25/10(6) children/year during the first 17 years of Danish cancer registration. The sex ratio (290 boys to 243 girls) was not significantly different from that of the child population in Denmark. In 219 cases the tumour was located in the supratentorial and in 314 in the infratentorial space. 93% of the tumours were histologically verified, with the following order of frequency for the most usual types: astrocytomas (all grades), medulloblastomas, ependymomas, and craniopharyngiomas. Follow-up was 100%. For the 345 children who survived for more than one month after operation or diagnosis, 36% were alive after 15 years. 119 patients were alive in April 1974 and these were all observed between 15-40 years after diagnosis and operation. Of these 44 had tumours in the supratentorial and 75 in the infratentorial space. 66% of the survivors with supratentorial and 90% with infratentorial tumours led a normal life. Most of the survivors had had a cerebellar astrocytoma, a supratentorial astrocytoma, an apendymoma or oligodendroglioma, but other histological diagnoses were also represented, especially in the supratentorial group. The long-term prognosis was especially bad for children with brain-stem tumours, infratentorial ependymomas and medulloblastomas.

Adolescent↗
PubMed1978

Intellectual development and brain size in 13 shunted hydrocephalic children.

A group of 13 successfully treated hydrocephalic children living a normal social life according to their ages has been examined to evaluate the possible correlation between their brain size, intellectual development and physical disability. The brain size was assesed by ventriculography prior to initial surgery and by computer tomography (CT-scanning) at the time of investigation 6--11 years after operation. The intellectural development was evaluated by psychological investigation of the children and by evaluation of their social adaptation. The physical disability was investigated by neurological examination. Significant improvement in ventricular size was demonstrated from pneumoencephalographic examinations prior to surgery and to the CT investigations. No prediction of the intellectual development could be based on the ventriculographies prior to initial surgery. In spite of positive trends, correlation trends, correlation between the ventricular size as determined by CT-scans and the IQ was not significant, possibly due to the small number of cases available for study.

Cerebral Ventriculography↗
PubMed1977

Ultrastructure of muscle biopsies in recent, short-term and long-term juvenile diabetes.

Muscle biopsies from juvenile diabetics were studied by electron microscopy and the results correlated to earlier published light microscopical abnormalities of the same biopsies. A total of 32 striated muscle biopsies from 29 juvenile recent, short-term and long-term diabetes were examined. The ages ranged from 16 to 43 years with a diabetes duration from 1 week to 32 years. The material was compared with biopsies from healthy persons of the same ages. The electron microscopy revealed degenerative changes of the striated muscle fibres which signify a neurogenic atrophy. No myopathic alterations were found. The capillaries in both the recent and long-term diabetics showed an extremely pronounced pinocytosis indicating an increased metabolic activity. In the long-term group the intramuscular capillaries both from upper and lower extremities displayed a definitely thickened basement membrane. In the recent and short-term group the capillary wall alterations were debatable. The motor end plate in the recent diabetics revealed minimal alterations. Contrary to this the long-term group showed severe alterations with occasional disappearance of the nerve fibres.

Adolescent↗
PubMed1977

Surgery of acoustic neuromas. Preliminary experience with a translabyrinthine approach.

Inspired by the works of William House, the authors formed an otoneurosurgical team in order to improve the results after surgery for acoustic neuromas. This paper deals with the preliminary results obtained with the translabyrinthine approach in 13 patients with acoustic neuromas. In 9 patients it was possible to remove the tumor totally with this approach, in 4 patients a second suboccipital operation was necessary to secure total removal. One small, 7 medium and 5 large tumors were encountered. The facial nerve was preserved in 83 per cent of the patients. One patient with a large tumor died after the second suboccipital operation. The relation between size of the tumor and the outcome of the operation is stressed, and in order to reduce the number of large tumors it is suggested that all patients with unilateral hearing loss should be suspected of having a neuroma, until the diagnosis has been disproved. It is concluded that the surgery for acoustic neuromas is otologic-neurosurgical teamwork, and that the treatment should be centralized.

Adult↗