Biomedical subjects

C G Helander

Publications and source records attributed to C G Helander.

15 recordsLinked to original sources

PubMed1992

Blunt basal head trauma: aspects of unconsciousness.

Two cases of street violence directed to the skull base level and transverse to the cervical axis are described. No skeletal damage. The violence resulted in the so-called "traumatic subarachnoid haemorrhage", an often used, unspecified forensic "diagnosis"; it was here revealed to be due to rupture of the wall of the posterior inferior cerebellar artery (p.i.c.a). However, this was only one of the possible explanations for the acute symptoms of unconsciousness (concussion) and almost immediate death. The careful examination of these two cases and of a series of control cases revealed that at the trauma, stress and strain may have occurred to arterial branches serving as feeding perforant vessels to the medulla oblongata; in these cases they were coursing directly from the p.i.c.a. region.--The type of direct impact has often been regarded as mild! However, its location suboccipitally as in these cases can become dangerous. The resulting direct or indirect deficit of brain stem functions are discussed in these cases as well as "concussion-related symptoms" resulting after other types of head and neck injury.

Adult↗

PubMed1992

Blunt basal head trauma: rupture of posterior inferior cerebellar artery.

Two cases are reported of rupture of posterior inferior cerebellar artery (PICA) from blunt basal head trauma. The anatomy at the site of rupture is discussed as a prerequisite for rupture. The rapid fatal course is also discussed. The authors propose that the forensic term "traumatic subarachnoid haemorrhage" ought to be abandoned and replaced by the nature and localization the source of bleeding, analogous to clinical practice at the spontaneous haemorrhage from rupture of aneurysm.

Adult↗

PubMed1991

Membrane lipids in the aging human brain.

The membrane lipid composition of human brain has been studied in 21 men and 18 women 60-97 years of age. This brain tissue series is unique, because it has been obtained only from individuals who lived a normal social life in their own homes and died suddenly and unexpectedly from arteriosclerotic heart disease or ruptured aortic aneurysms. They had no history of neurological or psychiatric disease. Macroscopic and microscopic examinations ruled out any signs of organic brain disorder. The percentage of solids diminished continuously during the whole period, but the marked individual differences suggested large variations in the hydration of the brain. The content of membrane lipids also diminished continuously up to 90 years of age, when a marked diminution in level of gangliosides and cerebrosides occurred, a result indicating a rapid reduction in amount of neuronal membranes and myelin. The clinical implications of the variation in brain hydration and the rapid loss of membrane lipids after 90 years of age are discussed.

Aged↗

PubMed1986

Aspects on pathology and neuropathology in head injury.

Some principal differences of the head injury materal available to clinicians, hospital pathologists and forensic pathologists are discussed with reference to the primary and secondary findings at focal and diffuse brain injury and intracranial injuries after trauma. The importance of cooperative understanding between the different disciplines is stressed in order to cover the whole head injury pattern. Examples are given. The importance of intracranial arterial hemorrhages is stressed and may also be the cause of a particular group of acute subdural hematomas; it may be of special prognostic importance because of their probable availability to successful surgery in the acute stage. The cause may be a tearing of arterial connections between the peripheral branches of the middle cerebral artery and the dura. The diagnosis of different types of primary diffuse brain injury is discussed with particular reference to the non-satisfactory common histological methods of investigation early after trauma. Diffuse brain injury due to hypoxia at the trauma can be serious but give few macroscopical findings; disseminated intravasal coagulation can appear isolated in the brain or be part of a systemic manifestation.

Brain↗

PubMed1979

Quantity of tomographic blurring.

A spiral tomographic movement gives rise to a lower quantity of blurring than does a circular movement with the same tomographic angle since in the former the focus comes nearer to the central point. It has been demonstrated that the transfer function may be used to express the quantity of blurring for different tomographic movements. For the sake of convenience the blurring quantity for every type of spiral movement may be expressed in terms of the tomographic angle of a circular movement giving rise to the same transfer function.

Technology, Radiologic↗

PubMed1978

Medichrome film as an alternative to silver-free recording systems.

A shortage of silver is forcing film manufacturers to lower the silver content of radiographic films. No further lowering seems possible without film quality being adversely affected. Various ways to solve the silver problem in the future are discussed and colour radiography is regarded as one solution since it makes possible a high degree of immediate recovery of silver. The feasibility and proper use of the only colour film available, Medichrome, is discussed. Suitable screens in order to compensate for the low sensitivity of the film without loss of image quality and a strong light source containing a monochromatic sodium lamp for inspection of dense areas are recommended.

Radiography↗

PubMed1977

Xerographic tomography.

Tomographic depiction using Xerox plates was compared with that of screen film tomography. The Xerox plates entail much higher demands as to the quality of tomographic blurring than screen film combinations. Circular or hypocycloid movements give rise to errors of depiction which are more disturbing in xerographic tomography due to the fact that the screen film combination has such properties as to be unable to record certain spurious signals present in the radiation relief, which appear in the higher-precision recording of the Xerox plates. This indicates that these plates are to be preferred if only the spurious signals can be eliminated. Suitable tomographic movements are described. To counteract the high radiation doses in xerotomography, it is suggested that specially constructed cassettes for simultaneous multisection tomography should be used.

Ear↗

PubMed1974