Biomedical subjects
Publications and source records attributed to L Bakay.
The history of the arachnoid membrane from antiquity to the present time is presented, including its anatomy, histology, and role in the absorption of cerebrospinal fluid. Special regard is given to the pioneering work of Key and Retzius.
The early contribution of various authors to the pathologic anatomy and clinical symptoms of meningiomas is presented with special regard to the work of Jean Cruveilhier.
The contribution to the treatment of head injuries from Richard Wiseman, a Royalist surgeon during the English Civil War culminating in the battle of Worcester (1651), is presented. Wiseman's surgical surgical skill and vast experience was expressed in his book based on 600 personally treated patients.
The life and contributions to neurosurgery of Francois Quesnay, a French surgeon who was active during the mid-18th century, are presented. Quesnay, still famous as economist and as the founder of one of the earliest systems of economics, is largely forgotten as a surgeon, although he was the first to advocate cortical incision and exploration of the brain for abscesses and tumors.
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Olfactory meningiomas are benign, slow-growing intracranial tumors arising from the dura along the cribriform plate. The first clinical symptom is anosmia followed, usually after several years, by dementia and visual deterioration. A series of 36 patients are presented; in all cases but one, their conditions were diagnosed late and not until the tumor had reached a very large size. By the time the proper diagnosis was made and the tumors were surgically removed, mental or visual disability was often irreversible. Conditions of patients initially seen with anosmia should be investigated by presently available noninvasive diagnostic methods including computed tomographic scanning.
Fourteen cases of gunshot wounds of the brain, evaluated by CT scanning are presented. The results indicate that CT scanning is superior to other diagnostic tests in missile wounds of the brain. In individual patients it revealed gross injury to the skull, the location of the bullet or its fragments and indriven bone fragments, the track of the bullet, the gross injury suffered by the brain, the extent of oedema, the presence of any intracranial haematoma and late cerebral atrophy. Visualization of the missile track is of particular importance; this cannot be achieved by any other diagnostic method. It is essential for the planning of the surgical approach in these lesions.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
The activity of mitochondrial enzymes (succinic dehydrogenase and cytochrome oxidase) and enzymes associated with blood-brain barrier function (butyrylcholinesterase and alkaline phosphatase) in the CNS of rats was studied from 5 minutes to 62 hours after cerebral concussion. There was a transient increase in succinic dehydrogenase activity during the first hour after concussion in the neurons of the structures close to the impact. The alkaline phosphatase activity, strongly positive in the walls of normal blood vessels, decreased within five minutes after concussion; it virtually disappeared in 15 minutes but returned to normal level after 62 hours. These findings are in good correlation with previous electron microscopic observations. Their significance is discussed.
Four cases are presented of marked periventricular oedema associated with hydrocephalus on CT scan. In one of the patients oedema, as well as the hydrocephalus, subsided after successful re-establishment of CSF absorption. The most likely explanation of the periventricular oedema is increased absorption of CSF by periventricular brain tissue.
Five patients surgically treated for unusual intracranial foreign bodies are presented. They include representative cases of the three most commonly encountered types of these injuries: industrial accidents, suicidal attempts and the result of criminal assault. Immediate radiological examination is mandatory because the deceptively small entrance wound is usually in no way commensurate with the large size of the foreign body the presence of which is frequently not suspected. The surgical removal of these foreign bodies requires careful pre-operative assessment to avoid hemorrhages and undue injury to the surrounding normal brain tissue.
Cerebral concussion was produced in rats by an iron pendulum hitting the external occipital protuberance. This resulted in loss of consciousness lasting from 3 to 10 minutes with prompt recovery and no focal neurological signs. The energy absorbed by the head at the impact was calculated to be about 1450 gm/cm. Light microscopic survey showed only minor pathological changes. However, electron microscopic observation revealed considerable alteration which began at 30 minutes, reached a peak at 1 hour, and disappeared at 24 hours after concussion. The salient changes included severe swelling of the neuronal mitochondria at the point of impact (occipital cortex), and extracellular edema at the site of contre coup (frontal lobe). Topographically, the most severe alteration was seen in structures at the craniospinal junction (medulla oblongata and upper cervical cord), consisting of both mitochondrial and edematous changes. Although there was no visible opening of the capillary interendothelial junctions, extravasated ferritin particles were accumulated in the edematous regions, indicating a transient increase in the permeability of the blood-brain barrier.
The nmr relaxation rate results show unequivocally that there are at least two fractions of tissue water in both normal and edematous white matter which do not exchange on an nmr time scale (i.e. at times of the order of milli-seconds to fraction of a second). In conjunction with the electron microscopic determination of the extracellular volumes of normal and edematous white matter, the relaxation results can be interpreted in terms of the following model. The two slowly-exchanging water components giving rise to the non-exponential relaxation correspond to cellular and extracellular water; edema changes the relaxation rate of the extracellular component much more than that of the cellular component (the extracellular component becoming more "liquid-like" in its relaxation). Such behavior is consistent with the properties of the extracellular water being due to rapid exchange between motionally restricted water adsorbed at the surface of myelin sheaths, and relatively unrestricted, bulk water. Edema presumably increases the relative amount of the "bulk" water between the axons.
The clinical symptoms of thirty patients with surgically treated posterior fossa meningiomas were reviewed. These included 16 cerebellopontine (CPA), 7 cerebellar, 4 carrefour-falco-tentorial (CFT), 2 foramen magnum, and 1 clivus meningiomas. Careful attention to clinical findings is necessary in diagnosing these tumors. With rare exception they have an insidious onset and even after having reached considerable size, the ensuing neurological abnormalities might not be revealing. On occasion there are false localizing neurological findings. Neuroradiological localization is essential to obtain accurate diagnosis and to plan the best operative approach. Radioactive brain scanning offers the best screening method. Although air studies remain useful, angiography of vessels of the posterior foss is assuming a dominant role in diagnosis and surgical planning.
A peculiar abnormality of the precentral cerebellar vein seen only in cystic astrocytoma of the vermis is reported. Implications of this angiographic finding are discussed. The importance of posterior fossa angiography (especially venography) in the diagnosis of posterior fossa mass lesions is emphasized.