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PubMed1980

The normal suprasellar subarachnoid space in computed tomography.

Changes in visibility or configuration of the suprasellar cistern are often the only signs on a CT scan of a patient with a juxtasellar expansion. Normal variations of this subarachnoid space on a CT scan are side for anatomical and technical reasons. The ability to differentiate between normal and abnormal in this area is essential in interpreting computed axial tomograms. To determine normal variants of the suprasellar cistern, 456 consecutive standard tomograms interpreted as normal were reviewed. The cistern was visible in 73.7% of the scans and the shape of the cistern was found to be either hexagonal (71.5%) or tetragonal (28.5%). The visible content of the cistern included the anterior part of the third ventricle (55.5%), the optic nerves and/or chiasm (52%) and the dorsum sellae (34.9%). The content of the cistern could not be accurately defined in 24.8% of the scans. In about one-fourth of the scans the suprasellar subarachnoid space was not visualised at all. If any doubt exists as to the visibility and configuration of the suprasellar cistern when there is a clinical suspicion of a juxtasellar tumour, additional investigations must be performed.

Brain↗
PubMed1980

Distribution of marked perilymph to the subarachnoidal space.

In guinea pigs the tympanic perilymph of the basal turn was marked with fluorescing rhodamine. In the first series one drop of a 2% solution of the dye was applied onto the round window membrane. Since the perilymphatic space was not opened, the physiologic state of the communicating fluids perilymph and CSF was maintained. The dye appeared within 3-5 min via cochlear aqueduct in the subarachnoidal space. In the dead animal the speed of distribution was significantly less. This most probably indicates a weak physiologic flow of the perilymph through the aqueduct to the subarachnoidal space in living animals. In the second series, 2 ng of lyophilized rhodamine was instilled directly into the tympanic perilymph near the round window. Though hardly any additional volume was brought into the perilymph, the distribution of the dye was distinctly greater as a sign of the considerable sensitivity of the fluid system, even by the slightest manipulation.

Animals↗
PubMed1996

Evidence for rapid fluid flow from the subarachnoid space into the spinal cord central canal in the rat.

Horseradish peroxidase (HRP) was used as a CSF tracer in Sprague-Dawley rats. One group of rats received an injection of HRP in the cisterna magna and a second group was injected in the thoracic spinal subarachnoid space. The animals were sacrificed 0, 10 or 30 min after HRP injection by rapid perfusion with paraformaldehyde and glutaraldehyde. In both groups, there was rapid HRP labeling of brain and spinal cord perivascular spaces. HRP was present in the central canal in a pattern that was not consistent with flow from the fourth ventricle: in both groups there were segments of unlabeled central canal between the fourth ventricle and central canal segments containing HRP. HRP-labeled perivascular spaces were seen in the central gray matter adjacent to the central canal. There was a distinctive pattern of interstitial HRP between perivascular spaces and the central canal. The results suggest that there is a normal flow of fluid from the subarachnoid space, into the perivascular spaces, across the interstitial space and into the central canal. The function of this flow may be to clear metabolites from the interstitial space. The existence of such a flow would add considerable support to the theory that non-communicating syringomyelia develops in segments of central canal isolated by occlusion or stenosis at each end.

Animals↗
PubMed1989

Spinal fluid profile following surgery in the subarachnoid space.

Neurotologic and skull base procedures that include dissection within the subarachnoid space carry with them the potential for meningitis. Postoperative aseptic leptomeningitis occurs more frequently than purulent bacterial meningitis. Differentiation between these two conditions early in the postoperative period is important to avoid delay in or unnecessary treatment. The definitive diagnosis is made with cerebral spinal fluid culture. Early differentiation between postoperative aseptic leptomeningitis and purulent bacterial meningitis on the basis of results of cerebral spinal fluid profile before cerebral spinal fluid culture would result in earlier appropriate therapy.

Anti-Bacterial Agents↗
PubMed1979

Measurement of the normal ventricular system and supratentorial subarachnoid space in children with computed tomography.

The normal ventricular system and subarachnoid space were evaluated on the CT scans of 155 children chosen from 1,400 pediatric CT examinations, and linear measurements were made. The left septum-caudate distance was greater than the right, and the width of the left anterior horn and size of the skull were larger in boys. The interhemispheric and sylvian fissures, the third ventricle and Evans' ratio were larger in the younger group (less than 3 years) than in the older (greater than or equal to 3 years), while the opposite was found for the cella media index and size of the skull. The size of the lateral ventricles (expressed by anterior horn width, septum-caudate distance and width of cella media) was not different in the two age groups of children. Normal limits for the linear measurements and indices are given in Table 2.

Adolescent↗
PubMed1999

A method for increasing the viability of the external portion of lumbar catheters placed in the spinal subarachnoid space of rats.

A method for direct catheterization of the lumbar subarachnoid space has recently been developed by Storkson et al. (1996) (J Neurosci Methods 1996;65:167-172) that may potentially improve upon the widely used method of Yaksh and Rudy (1976) (Physiol Behav 1976;17:1031-1036). This 'catheter-through-a-needle' technique inserts the catheter between lumbar vertebrae 5 (L5) and 6 (L6), which has been shown to reduce neurological impairment and post-surgical deaths. However, employing this technique allows the external portion of the chronic indwelling catheters to be easily damaged, resulting in approximately 50% attrition within 4 days after surgery. Therefore, we developed an easy and inexpensive method for protecting the external portion of the catheter that enhances catheter viability beyond 14 days after catheter implantation while also maintaining a low injection volume (8 microl). Moreover, this modification does not significantly alter the implantation methods developed by Storkson et al. (1996) (J Neurosci Methods 1996;65:167-172) and allows for more optimal catheter materials to be incorporated. Chronically implanted catheters (n = 70) with the external portion of the catheter protected, resulted in 4% attrition 7 days after surgery and 11% attrition 14 days after surgery. Approximately 5.5% of animals implanted showed very mild and transient neurological impairment.

Animals↗
PubMed1993

Drainage of molecules from subarachnoid space to spinal nerve roots and peripheral nerve of the rat. A study based on Evans blue-albumin and lanthanum as tracers.

The purpose of the present investigation was to find out if a compound injected into the spinal subarachnoid space, after having entered ventral and dorsal nerve roots, can be traced to the epineurial-perineurial sheaths and the endoneurium of peripheral nerves. This would indicate a centrifugal movement of substances from the cerebrospinal fluid along nerves; one route of drainage of cerebrospinal fluid which in the past has been widely discussed. In vivo studies were made using Evans blue-albumin and lanthanum chloride as tracers. Evans blue-albumin is macromolecular in size and emits a red fluorescence after exposure to ultraviolet light. Lanthanum ions are small and easily visible in the electron microscope. The tracers were injected into the cervical subarachnoid space and 15 min to 24 h later samples from roots, dorsal root ganglia, proximal part of spinal nerves and the median nerves were taken and further processed for detection of tracers. Fluorescence microscopy from samples removed 15 min and 24 h after the injection of Evans blue-albumin showed a red fluorescence of low intensity in the endoneurium of nerve roots, ganglia and proximal spinal nerve. After 24 h also the median nerve elicited some fluorescence. The sheaths around these structures were also fluorescent. Lanthanum was detected between cell layers of the nerve root sheath as well as inside the nerve root parenchyma. In about 50% of the samples from dorsal root ganglia extracellular lanthanum was found in the capsule. The tracer was also found in the epineurium of 50% of the spinal nerves and occasionally in the perineurium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Fenestrated capillaries in subarachnoid space in the caudal spinal cord of the premature rat: an electron microscopic observation.

The fine structure of the conus medullaris of the spinal cord and surrounding structures were studied in postnatal developing rats, with special attention being paid to the vasculature. The most striking finding was the presence of fenestrae in the capillary endothelium of the subarachnoid space. These structures were not obvious in adult rats. The fenestrated capillaries may influence fluid dynamics in the subarachnoid space of the spinal cord at the level of the conus medullaris, during early stage of postnatal development.

Animals↗
PubMedDate not supplied

Transplantation of encapsulated bovine chromaffin cells in the sheep subarachnoid space: a preclinical study for the treatment of cancer pain.

Chromaffin cells have been shown to release a combination of pain-reducing neuroactive compounds including catecholamines and opioid peptides. The allogeneic transplantation of chromaffin cells in the subarachnoid space has been shown to alleviate pain in various rodent models and possibly in terminal cancer patients. Because of the shortage of human cadaver donor tissue, we are investigating the possibility of transplanting xenogeneic cells in polymer capsules. In this technique, cells are surrounded by a permselective synthetic membrane whose pores are suitably sized to allow diffusion of nutrients, neurotransmitters and growth factors, but restrict the diffusion of the large molecules of the immune system and prevent contact with immunocompetent cells. The encapsulation technique therefore allows transplantation of xenogeneic tissue between species as well as retrieval of transplanted cells. Previously we have reported that encapsulated bovine chromaffin cells survive and alleviate pain in various rodent models. The purpose of the present study was to assess the feasibility of implanting a human sized device in a large animal model. Adrenals from 5 calves were surgically removed; chromaffin cells were isolated from these glands using a collagenase-based digestion-filtration technique. Cells were loaded into acrylic-based tubular (5 cm long, 920 microns wide) permselective capsules attached to silicone tethers. The capsules were maintained in vitro for at least 7 days following the encapsulation procedure. Nicotine evoked release was analyzed in a defined subgroup from each batch. One capsule was then implanted using a guiding cannula system in the lumbar subarachnoid space of each sheep for 4 (n = 5) and 8 (n = 1) wk. All capsules were retrieved intact by gentle pulling on the silicone tether. Except for one capsule, the evoked catecholamine release of the retrieved capsules was in the same range as that of other capsules from the same cohort that had been maintained in vitro. All retrieved capsules were devoid of host cell reaction. Clusters of viable cells dispersed in an alginate immobilizing matrix were observed throughout all the implanted capsules. This study demonstrates the feasibility of transplanting functional encapsulated xenogeneic chromaffin cells into the cerebrospinal fluid of a large animal model using a capsule of appropriate dimensions for human implants. We believe that these results suggest the appropriateness of human clinical trials in patients suffering from refractory terminal cancer pain.

Adrenal Glands↗
PubMed2005

The subarachnoid space develops early in the human embryonic period.

The anlage of the subarachnoid space is seen in embryos at stage 14 (33 days) in the innermost zone of the primary meninx as irregular spaces on the ventral surface of the spinal cord. At first this space is only on the ventral surface of the spinal cord. From stage 18 (44 days) on, when the dura mater proper is formed, the reticular tissue of the primary meninx and spaces are around the circumference of the spinal cord. These spaces gradually coalesce and contain many blood vessels.

Adult↗
PubMed1987

Influence of the spread and period of retention of Iotrolan in the subarachnoid space on the side effects rate in myelography.

Fifty patients underwent myelography with the newly developed CSF-isotonic, dimeric, non-ionic contrast medium Iotrolan. Repeat spinal and cranial computerised tomographic studies with measurement of the attenuation values were conducted to demonstrate the administered contrast medium in the spinal canal and intracranial subarachnoid space. The patients were examined neurologically, observed clinically and asked about concomitant symptoms. The period of retention and the spread of the contrast medium in the subarachnoid space was not found to have any influence on the side effects rate. In particular, no association was confirmed between intracranially demonstrable contrast medium and the occurrence of side effects.

Adult↗
PubMed1980

Respiratory effects of beta-endorphin, D-Ala2-met-enkephalinamide, and Met-enkephalin injected into the lateral ventricle and the pontomedullary subarachnoid space.

The respiratory effects of Met-enkephalin (900 microgram), D-Ala2-Met-enkephalinamide (10 microgram), and beta-endorphin (10 microgram) were studied and compared in lightly anesthetized cats, after injection into the lateral ventricle and into the pontomedullary subarachnoid space. The 3 peptides injected into the lateral ventricle induced equidepressant effects on respiration, but the duration of action and the involvement of either frequency or tidal volume varied considerably. Met-enkephalin was shorter-acting (45 min) than both D-Ala2-Met-enkephalinamide and beta-endorphin (over 5 h). The depression induced by beta-endorphin was preceded by a long-lasting stimulation of frequency. The effects were antagonized by i.v. naloxone, but the antagonism was not complete in one third of the animals. In the pontomedullary subarachnoid space, beta-endorphin failed to depress respiration significantly whereas Met-enkephalin induced an immediate and short-acting depression (15 min), and D-Ala2-Met-enkephalinamide depressed respiration for 2-4 h in a biphasic pattern. It is concluded that: (1) respiration is depressed by the 3 opiate peptides; (2) the effects of beta-endorphin on respiration, at the dose used in this study, are secondary to other actions on higher brain structures; and (3) Met-enkephalin and D-Ala2-Met-enkephalinamide seem to affect pontomedullary areas located near the ventral surface, although they may also interact with respiratory structures located more deeply in the brain stem.

Animals↗
PubMed1977

[Role of serum fibrinogen penetrating the subarachnoid space in the pathogenesis of brief cerebral arteriospasm].

A mixture of fibrinogen (4 ml in a 1 per cent solutions) and thrombin (10 I.U.) were instilled into the cisterma magna of 18 dogs which led to the formation of a fibrin clot in the subarachnoid space. This fibrin clot produced a spasm of the large cerebral arteries, which resulted in a narrowing to 84.8 +/- 1.8 per cent of the initial value. The subsequent administration of 400 units of fibrinolysin into the cisterna magna led to the dissolution of the fibrin clot and the dilatation of the arterie to 116.3 +/- 2.5 per cent of the initial value. Experiments carried out in 15 cats showed that, after being brought in the subarachnoid space, the spasmogenic factor of the clot, which consisted of all blood components, passes through the arachnoid into the subdural space. The penetration of the spasmogenic factor from the blood clot located on the surface of the arachnoid from the subdural to the subrarachnoid space was not observed. The arachnoid proves to be a membrane which can only be passed in one direction by the spasmogenic blood factor.

Animals↗
PubMed1988

A non-traumatic approach to ventral subarachnoid space near circle of Willis.

A non-traumatic approach to the subarachnoid space near the circle of Willis is demonstrated in this study. The approach is made between the olfactory bulb and frontal lobe. Following perfusion with Evans blue dye no leakage was observed into the parenchyma indicating no tissue damage had occurred. No gross bleeding or cerebral vasospasm was visible in the middle meningeal artery (dural), the surface pial blood vessels and the vessels of the circle of Willis. In conclusion, this technique can be successfully used for studies on experimental subarachnoid hemorrhage simulated on the ventral aspect of the brain near the circle of Willis without causing technique-associated cerebrovascular and parenchymal injury.

Animals↗
PubMed1980

Depression of reserpine-induced muscular rigidity in rats after administration of lisuride into the spinal subarachnoid space.

Muscular rigidity was induced by reserpine (10 mg/kg) in rats and the tonic activity of the gastrocnemius muscle was recorded in the electromyogram. Systemic administration of lisuride, an ergoline, resulted in a dose-dependent depression of rigidity. To examine the spinal cord as a site of action for lisuride to depress reserpine-induced rigidity, a method for the chronic catheterization of the lumbar spinal subarachnoid space was used, which allowed the administration of drugs to reserpinized, intact rats without anaesthesia. Lisuride injected into the lumbar spinal subarachnoid space resulted in a longlasting depression of rigidity. These results suggest that the spinal cord is an important site of action of lisuride.

Animals↗
PubMedDate not supplied

[Extra-cerebral intracranial fluid collections in childhood: differentiation between benign subarachnoid space enlargement and subdural effusion using color-coded duplex ultrasound].

BACKGROUND: Extracerebral fluid collections in infancy are a common diagnostic problem, because by noninvasive imaging studies (including cranial ultrasonography, CT and NMR), no definite differentiation between two distinct pathological conditions can be found until today: An enlargement of the subarachnoid spaces in children with macrocephaly is a frequent observation of mostly unknown etiology but is known to be associated with a good prognosis. If surgery is necessary in these patients, ventricular shunting is required. On the other hand subdural effusions are often of traumatic origin and require frequently neurosurgical intervention (subdural shunting). Most reports on extracerebral fluid collections in infancy have not differentiated between both pathological conditions and therefore reveal confusing results. Recent studies using magnetic resonance imaging have shown that vascular flow phenomena in the arachnoid space can be used to a reliable diagnosis, whereas previous noninvasive neuroimaging attempts including high resolution computerized tomography (CT) have been useless. PATIENTS AND METHODS: We investigated a cohort of 20 patients aged 4 mths to 30 mths (mean 10.5 +/- 6.6 months) 16 with the history of macrocephaly and normal neurological development and 4 patients after head trauma and symptoms of an elevated intracranial pressure. RESULTS: In all 16 patients with the clinical diagnosis of benign subarachnoid space enlargement colour coded Doppler sonography detected archnoid vessels within the fluid collection, furthermore high resolution ultrasound demonstrated the dural border of of the arachnoidea as an echogenic membrane, an observation useful as a further sign of the subarachnoid location of the fluid collection. In the 4 patients with subdural hematoma the fluid collection showed an increased echogenity, no vascular structures and no surrounding border. CONCLUSION: Out of these observations we conclude that high resolution ultrasound and colour-Doppler sonography are able to reliably differentiate between a subdural and a subarachnoid fluid collection. An NMR investigation with its higher risks (sedation, anesthesia) focused on this target only seems therefore to be not necessary in these patients.

Blood Flow Velocity↗
PubMed1997

Magnetic resonance imaging contrast media in the subarachnoid space. A comparison between gadodiamide injection and gadopentetate dimeglumine in an experimental study in pigs.

RATIONALE AND OBJECTIVES: The authors studied the neural tolerance and contrast enhancement of a nonionic, gadodiamide injection (gadolinium [Gd]-DTPA-BMA), and an ionic, gadopentetate dimeglumine (Gd-DTPA), contrast medium in the subarachnoid space of the pig. METHODS: Sixteen experiments were performed in eight pigs. Lumbar and lateral C1-C2 punctures were performed. Ten milliliters of Gd-DTPA-BMA or Gd-DTPA with Gd concentrations varying from of 500 mmol/L to 0.625 mmol/L were injected, in four experiments via the lumbar route and in 12 experiments via the C1-C2 puncture. RESULTS: Four pigs injected via the C1-C2 puncture with a Gd concentration of 500 mmol/L had signs of somatomotor irritation and all were paretic after 24 hours. No somatomotor effects were observed in the other experiments, where lower concentrations of Gd were used. Marked enhancement of the cerebrospinal fluid with no visible signal differences was obtained with concentrations from 10 to 0.625 mmol/L. CONCLUSIONS: Both Gd-DTPA-BMA and Gd-DTPA are remarkably well tolerated in the subarachnoid space. In doses relevant for imaging purposes no adverse effects were seen.

Animals↗