Exchange of inulin and dextran between blood and cerebrospinal fluid

1961 ◽  
Vol 201 (6) ◽  
pp. 1145-1148 ◽  
Author(s):  
Arthur R. Rothman ◽  
Emil J. Freireich ◽  
James R. Gaskins ◽  
Clifford S. Patlak ◽  
David P. Rall
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Venous System ◽  
Bulk Flow ◽  
Entry Rate ◽  
Important Means ◽  
Subarachnoid Spaces

C14-labeled inulin (mol. wt. 5,000) and C14-labeled dextran (mol. wt. 12,800 and 77,700) were studied for entry rate into CSF and steady state ratio of drug in cerebrospinal fluid (CSF) to drug in plasma, in nephrectomized dogs. For all three of these compounds the entry rates and steady state ratios were very similar. Exit rates of C14-inulin and C14-dextran (mol. wt. 77,700) were studied in nephrectomized and nonnephrectomized dogs. The exit rates were rapid and very similar for the two compounds. Acetazolamide increased the steady state ratio and decreased the exit rates significantly. These data suggest the presence of leaks in the blood CSF barrier of at least 60 A in diameter and indicate that bulk flow of CSF from the subarachnoid spaces to the venous system is an important means of exit of substances present in the CSF. Compounds which enter the CSF slowly fail to achieve diffusion equilibrium because of their relatively rapid exit by means of bulk flow.

Resistance to Outflow of Cerebrospinal Fluid Determined by Bolus Injection Technique and Constant Rate Steady State Infusion in Humans

Neurosurgery ◽  
1985 ◽  
Vol 16 (3) ◽  
pp. 336-340 ◽  
Author(s):  
Michael Kosteljanetz
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Bolus Injection ◽  
Point Of View ◽  
Injection Technique ◽  
Communicating Hydrocephalus ◽  
Constant Rate ◽  
High Degree ◽  
Infusion Technique

Abstract Two methods for the determination of resistance to the outflow of cerebrospinal fluid, the bolus injection technique and the constant rate steady state infusion technique, were compared. Thirty-two patients with a variety of intracranial diseases (usually communicating hydrocephalus) were studied. There was a high degree of correlation between the resistance values obtained with the two methods, but values based on the bolus injection technique were systematically and statistically significantly lower than those obtained with the constant rate infusion test. From a practical point of view. both methods were found to be applicable in a clinical setting.

Drainage of cerebral interstitial fluid into deep cervical lymph of the rabbit

1981 ◽  
Vol 240 (4) ◽  
pp. F329-F336 ◽  
Author(s):  
M. W. Bradbury ◽  
H. F. Cserr ◽  
R. J. Westrop
Keyword(s):  
Cerebrospinal Fluid ◽  
Caudate Nucleus ◽  
Subarachnoid Space ◽  
Interstitial Fluid ◽  
Bulk Flow ◽  
Perivascular Spaces ◽  
Csf Analysis ◽  
Intraventricular Injections ◽  
Intracerebral Microinjection ◽  
Do So

Lymph from the jugular lymph trunks of anesthetized rabbits has been continuously collected and radioiodinated albumin (RISA) therein estimated after microinjection of 1 microliter of 131I-albumin into the caudate nucleus, after single intraventricular injections, and during intraventricular infusions. Comparison of lymph at 7 and 25 h after intracerebral microinjection with efflux of radioactivity from whole brain suggests that about 50% of cleared radioactivity goes through lymph. Concentrations, normalized to cerebrospinal fluid (CSF), were much higher in lymph and retropharyngeal nodes after brain injection than after CSF injection or infusion. Also after brain injection, lymph and nodes contained more activity on injected side in contrast to lack of laterality after CSF administration. Calculation suggests that less than 30% of RISA cleared from brain can do so via a pool of well-mixed CSF. Analysis of tissues is compatible with much RISA draining by bulk flow via cerebral perivascular spaces plus passage from subarachnoid space of olfactory lobes into submucous spaces of nose and thus to lymph.

scholarly journals “Bucket” cerebrospinal fluid bulk flow—is it a fact or a fiction?

2018 ◽  
Vol 161 (2) ◽  
pp. 257-258 ◽  
Author(s):  
Olivier Balédent ◽  
Zofia Czosnyka ◽  
Marek Czosnyka
Keyword(s):  
Cerebrospinal Fluid ◽  
Bulk Flow

Comparison of Fluconazole Pharmacokinetics in Serum, Aqueous Humor, Vitreous Humor, and Cerebrospinal Fluid Following a Single Dose and at Steady State

1998 ◽  
Vol 14 (5) ◽  
pp. 459-471 ◽  
Author(s):  
UMAR K. MIAN ◽  
MARTIN MAYERS ◽  
YOGENDER GARG ◽  
QING-FENG LIU ◽  
GIRARD NEWCOMER ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Single Dose ◽  
Steady State ◽  
Aqueous Humor ◽  
Vitreous Humor

Gradient moment nulling for steady-state free precession MR imaging of cerebrospinal fluid

1991 ◽  
Vol 18 (5) ◽  
pp. 1038-1044 ◽  
Author(s):  
Michael L. Wood ◽  
Yuval Zur ◽  
Leo J. Neuringer
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Mr Imaging ◽  
Steady State Free Precession ◽  
Free Precession

scholarly journals Calcium Exchange and Contraction Strength of Guinea Pig Atrium in Normal and Hypertonic Media

1969 ◽  
Vol 54 (4) ◽  
pp. 494-511 ◽  
Author(s):  
Gerald R. Little ◽  
William W. Sleator
Keyword(s):  
Steady State ◽  
Ion Exchange ◽  
Guinea Pig ◽  
Extracellular Space ◽  
Entry Rate ◽  
Steady State Condition ◽  
Peak Tension ◽  
Guinea Pig Atrium ◽  
Calcium Exchange ◽  
The Difference

A Krebs-Henseleit (KH) medium made hypertonic by adding nonpermeant molecules substantially increased the isometric peak tension at steady-state contractions below 3 per sec in guinea pig atrium at 27°C. Action potential durations were decreased. KH plus 100 mM raffinose or sucrose resulted in similar and nearly maximal changes which were essentially reversible upon return to normal KH. When one active contracting atrium was used to passively stretch a second atrium, the difference in Ca ion exchange (1 min exchange with the extracellular space) between active and stretched atria significantly increased at 1 per sec and at 2 per sec in going from normal to 100 mM hypertonic KH. The calculated mean Ca ion cellular exchange per beat per 100 g of cells (a) doubled in changing from normal to 100 mM hypertonic KH, and (b) decreased slightly in changing from contractions of 1 per sec to 2 per sec in normal KH. These data are consistent with the hypothesis (a) that Ca ion entry per beat from the extracellular space is proportional to membrane depolarized time with a constant medium and a steady-state condition, and the hypothesis (b) that 100 mM hypertonicity doubles the Ca ion entry rate during depolarization. These data enable rejection of the hypothesis that the peak tension is proportional to the Ca ion entry per beat from the extracellular space under steady-state conditions, and suggest that any additional Ca ion involved in the larger contractions at higher frequencies comes from an increase in Ca ion available from intracellular stores.

scholarly journals Levofloxacin Disposition in Cerebrospinal Fluid in Patients with External Ventriculostomy

2003 ◽  
Vol 47 (10) ◽  
pp. 3104-3108 ◽  
Author(s):  
Federico Pea ◽  
Federica Pavan ◽  
Ennio Nascimben ◽  
Claudio Benetton ◽  
Pier Giorgio Scotton ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Bacterial Meningitis ◽  
Acute Bacterial Meningitis ◽  
Terminal Phase ◽  
Communicating Hydrocephalus ◽  
Synergistic Activity ◽  
Dosing Interval ◽  
Concentration Time ◽  
Meningeal Inflammation

ABSTRACT In vitro levofloxacin exhibits both potent or intermediate activity against most of the pathogens frequently responsible for acute bacterial meningitis and synergistic activity with some beta-lactams. Since levofloxacin was shown to penetrate the cerebrospinal fluid (CSF) during meningeal inflammation both in animals and in humans, the disposition of levofloxacin in CSF was studied in 10 inpatients with external ventriculostomy because of communicating hydrocephalus related to subarachnoid occlusion due to cerebral accidents who were treated with 500 mg of levofloxacin intravenously twice a day because of extracerebral infections. Plasma and CSF concentration-time profiles and pharmacokinetics were assessed at steady state. Plasma and CSF levofloxacin concentrations were analyzed by high-pressure liquid chromatography. The peak concentration of levofloxacin at steady state (C max ss)was 10.45 mg/liter in plasma and 4.06 mg/liter in CSF, respectively, with the ratio of the C max ss in CSF to the C max ss in plasma being 0.47. The areas under the concentration-time curves during the 12-h dosing interval (AUC0-τs) were 47.69 mg · h/liter for plasma and 33.42 mg · h/liter for CSF, with the ratio of the AUC0-τ for CSF to the AUC0-τ for plasma being 0.71. The terminal-phase half-life of levofloxacin in CSF was longer than that in plasma (7.02 ± 1.57 and 5.51 ± 1.36 h, respectively; P = 0.034). The ratio of the levofloxacin concentration in CSF to the concentration in plasma progressively increased with time, from 0.30 immediately after dosing to 0.99 at the end of the dosing interval. In the ventricular CSF of patients with uninflamed meninges, levofloxacin was shown to provide optimal exposure, which approximately corresponded to the level of exposure of the unbound drug in plasma. The findings provide support for trials of levofloxacin with twice-daily dosing in combination with a reference beta-lactam for the treatment of bacterial meningitis in adults. This cotreatment could be useful both for overcoming Streptococcus pneumoniae resistance and for enabling optimal exposure of the CSF to at least one antibacterial agent for the overall treatment period.

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