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Biomedical subjects

A E Marlin

Publications and source records attributed to A E Marlin.

At least 37 records · Page 2Linked to original sources
PubMed1987

Intracranial pressure measurement from the anterior fontanelle utilizing a pneumoelectronic switch.

A newly developed infant cranial model shows that accurate, reproducible, and noninvasive measurements of intracranial pressure (ICP) can be made from the anterior fontanelle when fontanelle pressure is referenced from the bony margins adjacent to the fontanelle opening. Also, this model provides insight into the elastic properties of the fontanelle membrane and the pressure/volume relationships governing ICP transmission through the fontanelle window. An anterior fontanelle pressure monitor design based on data from the infant cranial model was used to monitor anterior fontanelle pressure in three infants with elevated ICP and previously inserted ventricular catheters. Measured anterior fontanelle pressure was highly correlated to ICP (r = 0.962) with high reproducibility after blind application and reapplication. Base line adjustment and in situ recalibration were easily achieved, with the monitor showing no sensitivity to patient movement and excellent frequency response.

Humans↗
PubMed1985

Coxsackievirus group B antibodies in the ventricular fluid of infants with severe anatomic defects in the central nervous system.

Ventricular fluids from four of 28 newborn infants who were initially seen with severe congenital anatomic defects in the central nervous system contained neutralizing antibody to at least one serotype of coxsackieviruses group B. Two of the four infants with anti-coxsackieviruses group B antibody in the ventricular fluid did not have a detectable level of the same antibody(ies) in their serum. The ventricular fluid of one of the infants had immunoglobulin M neutralizing antibody directed against coxsackievirus B6. Of 11 mother-infant pairs that had neutralizing antibody to coxsackieviruses group B in both sera, nearly half had antibodies directed against more than one serotype. These data suggest the possibility of an association between congenital infections with coxsackieviruses group B and rare severe CNS defects.

Antibodies, Viral↗
PubMed1983

Jefferson fractures in children. Case report.

Jefferson fractures in children are exceedingly rare. A case in a 2-year-old is reported, and the other only case in the literature is reprinted. The mechanism of fracture is probably separation of the lateral masses by a force transmitted from the vertex. Because these fractures are not usually associated with neurological deficits, and because of the poor detail obtained with conventional radiography in a child, these fractures may be overlooked. Computerized tomography provides superb definition of this lesion. The preferred mode of treatment is immobilization.

Cervical Atlas↗
PubMed1981

Furosemide and human head injury.

Intracranial pressure was maintained below 20 torr with the administration of intravenous furosemide (Lasix, Hoechst-Roussel) in addition to routine pharmacologic and mechanical procedures in 15 severely head-injured patients undergoing surgery for intracranial hematomas. Control of intracranial pressure in these patients was attributed to diuresis, carbonic anhydrase inhibition, decreased cerebrospinal fluid (CSF) production, and decreased central venous pressure. Furosemide may also improve cerebral microcirculation during continued administration at specific intervals by the inhibition of astroglial swelling.

Adult↗
PubMed1980

Effect of the dural application of Zenker's solution on the feline brain.

Zenker's solution is a tissue fixative containing mercuric chloride, potassium bichromate, sodium sulfate, and glacial acetic acid. In 1956, Anderson and Johnson reported its use in clinical neurosurgery. They applied the solution to the exposed dura after craniectomy. Delayed bone formation was thought to be due to the suppression of the osteoblastic activity of the outer layer of the dura. The fixative has since become a well-accepted adjuvant to the treatment of craniosynostosis. In 1972, Pawl and Sugar reported postoperative seizures in 6 of 34 patients treated with this solution. They assumed that the fixative penetrated the dura and irritated or damaged the cortex. To clarify the effect of Zenker's solution on the underlying brain, we performed bilateral parasagittal craniectomies in a group of kittens and adult cats. Zenker's solution was applied to one side and the other side served as a control. The animals were killed after periods varying from 24 hours to 2 months. We then examined the cortex under the craniectomies. There was immediate breakdown of the blood-brain barrier, as evidenced by the penetration of intravenous Evans blue. In the postoperative period investigated, an inflammatory response in the underlying brain with thickening of the arachnoid occurred. The results and implications of these experiments are presented. (Neurosurgery, 6: 45--48, 1980)

Acetates↗
PubMed1980

Protection of the cortical mantle in premature infants with posthemorrhagic hydrocephalus.

Premature infants weighing under 1500 g are now surviving because of technical and medical advances in the field of neonatology. Up to 70% of these babies will have intracranial hemorrhages. The management of posthemorrhagic hydrocephalus in these children with multiple other medical problems has thus become quite significant. This paper reports the results of the placement of a subcutaneous ventricular reservoir in 12 of these low birth weight infants in an attempt to protect their cortical mantle until their medical problems resolve and the risks and complications of shunting are acceptable. The infants were selected on the basis of clinically progressive hydrocephalus, multiple medical problems, and the failure of lumbar punctures to control the hydrocephalus. The placement of the reservoir was carried out in the neonatal intensive care unit and there were daily aspirations of cerebrospinal fluid. In all of the patients the hydrocephalus and increased intracranial pressure were controlled, with a stabilization of or an increase in the cortical mantle. Seven infants died from other problems associated with their prematurity. Seven required shunts when their medical problems resolved; one, now 1 year of age, has not required a shunting procedure.

Catheterization↗
PubMed1979

Subclavian steal syndrome. Part 1: Proximal vertebral to common carotid artery transposition in three patients, and historical review.

Three patients with central nervous system symptoms due to subclavian steal syndrome were treated with proximal vertebral to common carotid artery transposition. Neurological symptoms were relieved or improved in all three, with no decrease in blood pressure or pulse in the ipsilateral upper extremity. The colorful history of this syndrome is reviewed, and the various surgical approaches to its treatment are discussed. Although the literature suggests that the commonly used carotid to subclavian artery bypass graft and other similar extrathoracic procedures are generally safe and effective for relief of symptoms of the steal, there is also evidence that these bypasses may fail to restore antegrade flow in the vertebral artery, and, in fact, may steal from the carotid artery. Thus, the blood flow provided to the brain by these procedure may be hardly more than that provided by vertebral artery ligation, whereas the principal effect is to restore blood flow into the upper extremity. Vertebral artery ligation alone has been used in 20 patients, with neurological improvement in all cases and production of persistent intermittent brachial claudication in only one. These considerations and our patient experience suggest that a relatively simple operation, proximal vertebral to common carotid artery transposition, which emphasizes restoration of flow to the brain rather than to the upper extremity, may be preferable for most patients with neurological symptoms of subclavian steal syndrome.

Adult↗
PubMed1979

Subclavian steal syndrome. Part 2: Intraoperative vertebral artery blood flow measurement.

Intraoperative vertebral artery blood flow was measured in two patients with symptomatic subclavian steal syndrome, before and after proximal end-to-side vertebral to common carotid artery transposition. This confirmed retrograde flow in the vertebral artery before transposition, and antegrade flow after transposition. The measured flow rates were compared to values in other series involving different operative procedures for correction of symptomatic subclavian steal. The greatest mean antegrade flow rates in the vertebral artery were restored by proximal end-to-side vertebral to common carotid artery transposition.

Collateral Circulation↗
PubMed1978

Kaolin-induced hydrocephalus impairs CSF secretion by the choroid plexus.

CSF volume flow and sodium (Na+)-influx rates in normal and kaolin-induced hydrocephalic cats were measured during ventricular perfusion with anisotonic sucrose solutions. When ventricular fluid osmolality was 120 mOsm, CSF volume flow ceased for both groups of cats. As ventricular fluid osmolality was increased, the CSF volume flow rate of normal cats increased to 70 microliter per minute, and in hydrocephalic cats to 40 microliter per minute. In normal cats, for ventricular fluid osmolality between 50 and 350 mOsm, Na+-influx was constant and thought to occur by diffusion; while for higher osmolalities, Na+-influx increased. In hydrocephalic cats, Na+-influx increased over the entire range of ventricular osmolality but was less than in normal cats. Acetazolamide decreased the CSF volume flow in normal cats by 40 percent, but was ineffective in hydrocephalic cats. These results suggest that CSF secretion by the choroid plexus of cats with kaolin-induced hydrocephalus is impaired.

Animals↗
PubMed1977

Sodium exchange between blood, brain, and CSF in normal and hydrocephalic cats.

The exchange of sodium between blood, brain, and cerebrospinal fluid was studied in normal and kaolin-induced hydrocephalic cats. The ventricles were perfused to measure fluid formation and Na+ exchange rates. 22Na was added to the perfusion fluid or injected intravenously as a tracer for Na+ movement. Na+ and 22Na were also measured in cortical gray and white matter. Na+ relative specific activities were calculated for brain, effluent fluid, and serum. With 22Na in the perfusion fluid, Na+ exchange was not different from nascent Na+ influx for both normal and hydrocephalic cats. Na+ relative specific activities of cortical gray and white matter were 10 times greater in hydrocephalic than in normal cats. This difference in Na+ relative specific activity for brain may be due to a higher diffusion constant or to a lower brain capillary permeability. When 22Na was given intravenously, the Na+ diffusional exchange for normal cats was less than that measured when 22Na+ was in the perfusion fluid. In hydrocephalic cats, the Na+ diffusional exchange was effectively zero. Na+ relative specific activities of cortical gray and white matter were the same for normal and hydrocephalic cats. These findings suggest that the impaired Na+ diffusional exchange may be due to pathological changes in the choroid plexus.

Animals↗
PubMed1976

On the movement of fluid through the brain of hydrocephalic cats.

The effects of changes in serum osmolality on the volume flow of fluid into the cerebral ventricles and on brain water content was examined in cats with kaolin-induced hydrocephalus. Slopes of the regression lines relating volume flow and serum osmolality for both normal and hydrocephalic cats are the same. The constant difference in flow rates between the two lines, 7 mul per minute, is probably due to impaired choroid plexuow rates between the two lines, 7 mul per minute, is probably due to impaired choroid plexus function of the hydrocephalic cats. The osmotic pressure gradient that causes the flow of fluid is therefore probably between blood and brain. Under these conditions changes in brain water content of hydrocephalic cats were smaller than in normals and can be related to the edema present in this disorder. Despite the inflammatory response to kaolin, the blood-brain barrier remains intact. From the calculated filtration coefficient, it can be inferred that the flow of water from serum through brain and into cerebrospinal fluid is limited by the resistance of fluid flow through the brain.

Animals↗
PubMed1975

Changes in regional blood-flow and water content of brain and spinal cord in acute and chronic experimental hydrocephalus.

The effects of kaolin-induced hydrocephalus on regional blood-flow and water content of cat brain and spinal cord were measured. The role of the central canal of the spinal cord as an alternative pathway for cerebrospinal fluid in experimental hydrocephalus was also studied by positive contrast ventriculography. In comparison with normal cats, blood-flow in the cerebrum, cerebellum and brain stem of cats with acute hydrocephalus was reduced by more than 20 per cent: in those with chronic hydrocephalus it was reduced by only 12 per cent. There was an absolute increase of 1-5 per cent in water content of the brain in cats with acute hydrocephalus. Water content in the spinal cord was increased by 6 per cent in cats with acute hydrocephalus and by 8 per cent in those with chronic hydrocephalus. When the increased water-content was taken into account, hydrocephalus caused no significant change in blood-flow in the cervical, thoracic or lumbar spinal cord. Contrast material perfused through the ventricles of hydrocephalic cats flowed directly into the enlarged central canal of the spinal cord. Kaolin-induced arachnoiditis completely obstructed communication between the ventricles and the cranial subarachnoid space. The contrast material in the central canal communicated both with the cavities extending into the dorsal columns and with the spinal subarachnoid space. When kaolin was injected directly into the spinal subarachnoid space there was an increase in spinal water-content, without an enlarged central canal. These results suggest that in addition to kaolin-induced arachnoiditis, increased intraluminal pressure is necessary to enlarge the central canal.

Acute Disease↗
PubMedDate not supplied

Custom fitted thermoplastic Minerva jackets in the treatment of cervical spine instability in preschool age children.

The options for cervical spine stabilization have traditionally been the Minerva jacket (MJ) or the halo brace. In the preschool age child both of these devices have significant drawbacks; the halo brace because of its erosion and difficulty providing adequate fixation due to the thin calvarium of the young child and the MJ because of its bulk and weight. With the advent of polyethylene plastics, MJs are a more viable option without the disadvantages noted above. Six cases of cervical spine instability in preschool age children treated with a custom-molded MJ are presented. All patients achieved cervical spine stability with minimal morbidity. This technique is recommended as an alternative to the halo brace, as it provides reliable and satisfactory treatment of these difficult problems in preschool children.

Casts, Surgical↗
PubMedDate not supplied

Continuous external drainage in the treatment of subdural hematomas of infancy.

A series of 16 patients with chronic or subacute subdural hematomas treated with continuous external drainage of the subdural space is reviewed. Of these only 44% went on to require subdural-peritoneal shunt placement. There were no complications in treatment and no clinical or laboratory evidence of infection in any case. The outcome, measured by neurological examination, was not different between the shunted and nonshunted groups. In conclusion, continuous external drainage of the subdural space in chronic and subacute hematomas of infancy frequently is an effective, definitive treatment. This approach should be considered as the initial procedure prior to subdural-peritoneal shunting.

Catheters, Indwelling↗
PubMedDate not supplied

Transient eye closure after posterior fossa tumor surgery in children.

Transient cerebellar eye closure following posterior fossa tumor surgery in children has recently been observed. This phenomenon is characterized by a transient inability to open the eyes postoperatively with complete resolution within 4-6 days. Presented are four cases of transient cerebellar eye closure after posterior fossa tumor surgery in children. Possible mechanisms are reviewed with regard to historical works of cerebellar stimulation in man, and anatomical structures and pathways which might be involved.

Adolescent↗