Further data on the acute effect of intravenous steroids on canine CSF secretion and absorption

1979 ◽  
Vol 50 (4) ◽  
pp. 477-482 ◽  
Author(s):  
A. Richard Vela ◽  
Michael E. Carey ◽  
Bruce M. Thompson
Keyword(s):  
Acute Effect ◽  
Resistance Mechanisms ◽  
Outflow Resistance ◽  
Intravenous Methylprednisolone ◽  
Content Type ◽  
Difference Of Opinion ◽  
Ventriculocisternal Perfusion ◽  
Intravenous Steroids ◽  
Csf Production ◽  
Csf Absorption

✓ Considerable difference of opinion has arisen as to whether intravenously administered steroids affect cerebrospinal fluid (CSF) production in the acute laboratory animal undergoing ventriculocisternal perfusion. Our experiments with ventriculocisternal perfusion in dogs indicate that, when given intravenously, neither dexamethasone, methylprednisolone, hydrocortisone, nor aldosterone result in a significant, acute effect upon CSF production. Similarly, CSF absorption and outflow resistance mechanisms are not acutely affected by intravenous methylprednisolone, hydrocortisone, and aldosterone. Dexamethasone also probably does not produce an immediate effect upon CSF absorption.

Acute effect of glycerol on net cerebrospinal fluid production in dogs

1985 ◽  
Vol 63 (5) ◽  
pp. 759-762 ◽  
Author(s):  
Huda Y. Zoghbi ◽  
Sada Okumura ◽  
John P. Laurent ◽  
Marvin A. Fishman
Keyword(s):  
Cerebrospinal Fluid ◽  
Acute Effect ◽  
Serum Osmolality ◽  
Percentage Change ◽  
Perfusion Technique ◽  
Content Type ◽  
Ventriculocisternal Perfusion ◽  
Fluid Production ◽  
The Mean ◽  
Csf Production

✓ The effect of glycerol administration on cerebrospinal fluid (CSF) formation in dogs was studied by means of a ventriculocisternal perfusion technique. Net CSF production rate decreased after oral administration of glycerol (3 gm/kg) from a baseline level of 42.33 ± 6.68 µl/min (mean ± standard error) to a trough of 10.33 ± 4.88 µl/min at 90 minutes after administration (p < 0.025). Serum osmolality concomitantly increased from a baseline value of 296 ± 2.83 to 309 ± 4.7 mOsm/kg H2O at 90 minutes. The mean percentage change in CSF production inversely correlated to the mean percentage change in serum osmolality, r = −0.85. Thus, glycerol administration decreases net CSF formation, and this effect may be related in part to the rise in serum osmolality.

Compartmental analysis of compliance and outflow resistance of the cerebrospinal fluid system

1975 ◽  
Vol 43 (5) ◽  
pp. 523-534 ◽  
Author(s):  
Anthony Marmarou ◽  
Kenneth Shulman ◽  
James LaMorgese
Keyword(s):  
Cerebrospinal Fluid ◽  
Compartmental Analysis ◽  
Pressure Data ◽  
Outflow Resistance ◽  
Fluid System ◽  
Content Type ◽  
Spinal Axis ◽  
Pressure Dynamics ◽  
Total Compliance ◽  
Csf Absorption

✓ The distribution of compliance and outflow resistance between cerebral and spinal compartments was measured in anesthetized, ventilated cats by analysis of the cerebrospinal fluid (CSF) pressure response to changes in CSF volume. Cerebral and spinal compartments were isolated by inflating a balloon positioned epidurally at the level of C-6. The change of CSF volume per unit change in pressure (compliance) and change of CSF volume per unit of time (absorption) were evaluated by inserting pressure data from the experimental responses into a series of equations developed from a mathematical model. It was found that 68% of total compliance is contributed by the cerebral compartment while the remaining 32% is contained within the spinal axis. The cerebral compartment accounted for 84% of total CSF absorption. The mechanism for spinal absorption appears to be similar in that no differences were obvious on the basis of pressure dynamics.

Effect of systemic arterial hypotension on the rate of cerebrospinal fluid formation in dogs

1974 ◽  
Vol 41 (3) ◽  
pp. 350-355 ◽  
Author(s):  
Michael E. Carey ◽  
A. Richard Vela
Keyword(s):  
Blood Pressure ◽  
Cerebrospinal Fluid ◽  
Mean Arterial Blood Pressure ◽  
Content Type ◽  
Arterial Blood ◽  
Ventriculocisternal Perfusion ◽  
Fluid Formation ◽  
The Mean ◽  
Csf Production ◽  
Fine Print

✓The rate of cerebrospinal fluid (CSF) production in dogs was measured by ventriculocisternal perfusion with artificial CSF containing inulin. In normotensive animals, the average CSF production was 36 ± 6 µl/min. When the mean arterial blood pressure was reduced to 62 ± 1 mm Hg, the CSF production fell to 22 ± 5 µl/min, a 39% reduction in fluid formation. The authors briefly discuss various hypotheses to explain this reduction.

CSF dynamics in patients with subarachnoid and/or intraventricular hemorrhage

1984 ◽  
Vol 60 (5) ◽  
pp. 940-946 ◽  
Author(s):  
Michael Kosteljanetz
Keyword(s):  
Intraventricular Hemorrhage ◽  
Bolus Injection ◽  
Outflow Resistance ◽  
Csf Dynamics ◽  
Content Type ◽  
Constant Rate ◽  
Acute Subarachnoid Hemorrhage ◽  
Csf Diversion ◽  
Csf Absorption ◽  
Fine Print

✓ The purpose of this study was to examine the extent to which reduction of cerebrospinal fluid (CSF) absorption contributes to raised intracranial pressure (ICP) in patients with acute subarachnoid hemorrhage (SAH). Seventeen patients suffering from SAH and/or intraventricular hemorrhage were studied; all were admitted in Grades II to V according to Hunt and Hess. Eleven patients had a proven aneurysm. The ICP, monitored via an intraventricular catheter, was above 15 mm Hg (2 kPa) during part of the monitoring period in all patients. B-waves at 1/min were noted in all patients. Resistance to outflow of CSF was determined by the following techniques: 1) bolus injection; 2) constant-rate steady-state infusion; or 3) controlled withdrawal (“inverse infusion”). Resistance to outflow of CSF was increased in all patients, ranging from 11.5 to 85 mm Hg/ml/min. The ICP was linearly correlated with outflow resistance. Four (50%) of the eight survivors required a shunt. Neither the presence of hydrocephalus on admission, nor the level of ICP, nor the magnitude of resistance to outflow of CSF was clearly related to the requirement of a permanent CSF diversion.

Effect of intrathecal fibrinolysis on cerebrospinal fluid absorption after experimental subarachnoid hemorrhage

1991 ◽  
Vol 74 (5) ◽  
pp. 789-793 ◽  
Author(s):  
Thomas Brinker ◽  
Volker Seifert ◽  
Dietmar Stolke
Keyword(s):  
Cerebrospinal Fluid ◽  
Subarachnoid Hemorrhage ◽  
Autologous Blood ◽  
Recombinant Tissue Plasminogen Activator ◽  
Outflow Resistance ◽  
Content Type ◽  
Experimental Subarachnoid Hemorrhage ◽  
Logarithmic Relationship ◽  
Subarachnoid Blood ◽  
Csf Absorption

✓ The effect of intrathecal fibrinolysis on cerebrospinal fluid (CSF) absorption was investigated after experimental subarachnoid hemorrhage (SAH). In 11 cats, SAH was induced by intracisternal application of 1 to 4 ml of fresh autologous blood. Thirty minutes after the experimental SAH, the CSF outflow resistance was found to be elevated from a median of 77 mm Hg/ml/min (range 41.3 to 109 mm Hg/ml/min) to a median of 580 mm Hg/ml/min (range 104 to 7000 mm Hg/ml/min). A logarithmic relationship could be demonstrated between the volume of subarachnoid blood and the elevation of the CSF outflow resistance. The intrathecal application of 2 mg of recombinant tissue plasminogen activator (rt-PA), which is a fibrinolytic substance suitable for lysis of subarachnoid blood clots in man, resulted in an almost total restoration of CSF absorption after experimental SAH. The CSF outflow resistance after SAH was lowered by application of rt-PA from a median of 1028.05 mm Hg/ml/min (range 394 to 7000 mm Hg/ml/min) to 79 mm Hg/ml/min (range 56.7 to 223 mm Hg/ml/min). It is concluded that the impairment of CSF absorption after SAH may play an important role in the pathogenesis of post-hemorrhagic vasospasm.

Closed recirculatory spinal subarachnoid perfusion for determining CSF dynamics

1982 ◽  
Vol 56 (3) ◽  
pp. 368-372 ◽  
Author(s):  
Alan A. Artru ◽  
Michael Nugent ◽  
John D. Michenfelder
Keyword(s):  
Nitrous Oxide ◽  
New Method ◽  
Csf Dynamics ◽  
Established Method ◽  
Content Type ◽  
Perfusion Method ◽  
Ventriculocisternal Perfusion ◽  
Nonsteady State ◽  
Csf Production

✓ A new method for determining rates of cerebrospinal fluid (CSF) production under nonsteady-state conditions, namely, closed recirculatory spinal subarachnoid perfusion, was used to determine the effect of enflurane on the rate of CSF production in dogs. Considerable variability in results was observed such that there was no statistical difference in rates of production among animals that received enflurane 2.2%, enflurane 2.2% and nitrous oxide 60% to 70%, enflurane 3.2% and nitrous oxide 60% to 70%, or nitrous oxide 60% to 70% (controls). Possible sources of variability were sought in additional studies using a modification of the new method, and in an in vitro model. The results were compared to those obtained using an established method for determining rates of CSF production, namely, open ventriculocisternal perfusion. It was concluded that the sources of variability in the closed recirculatory method relate in part to adherence of the fluorescein-conjugated albumin tracer to glass and other surfaces, and to uneven flow and distribution of the tracer in the recirculatory system. When the open ventriculocisternal perfusion method was used, consistent results were obtained, demonstrating that CSF production rate increased significantly in animals that received enflurane. The authors conclude that the new closed recirculatory method is less reliable than the classical open perfusion method.

scholarly journals Multicenter Clinical and Molecular Epidemiological Analysis of Bacteremia Due to Carbapenem-Resistant Enterobacteriaceae (CRE) in the CRE Epicenter of the United States

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Michael J. Satlin ◽  
Liang Chen ◽  
Gopi Patel ◽  
Angela Gomez-Simmonds ◽  
Gregory Weston ◽  
...  
Keyword(s):  
New York ◽  
Empirical Therapy ◽  
Carbapenem Resistance ◽  
The United States ◽  
Resistance Mechanisms ◽  
Rapid Diagnostics ◽  
Multicenter Studies ◽  
Content Type ◽  
Medical Centers ◽  
Carbapenem Resistant

ABSTRACT Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types (cps), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae, Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC-Kp). The wzi154 allele, corresponding to cps-2, was present in 93% of KPC-3-Kp, whereas KPC-2-Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3-Kp had an CAZ-AVI MIC of ≥4/4 μg/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3-Kp bacteremia (adjusted odds ratio [aOR], 2.58; P = 0.045), cancer (aOR, 3.61, P = 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P = 0.03) were independently associated with mortality. Active empirical therapy and combination therapy were not associated with survival. Despite a decade of experience with CRE, patients with CRE bacteremia have protracted delays in appropriate therapies and high mortality rates, highlighting the need for rapid diagnostics and evaluation of new therapeutics.

Surgical removal of bilateral papillomas of the choroid plexus of the lateral ventricles with resolution of hydrocephalus

1979 ◽  
Vol 50 (5) ◽  
pp. 677-681 ◽  
Author(s):  
Steven K. Gudeman ◽  
Humbert G. Sullivan ◽  
Michael J. Rosner ◽  
Donald P. Becker
Keyword(s):  
Cerebrospinal Fluid ◽  
Choroid Plexus ◽  
Large Volume ◽  
Surgical Removal ◽  
Tumor Removal ◽  
Content Type ◽  
Lateral Ventricles ◽  
Csf Diversion ◽  
Csf Production ◽  
Fine Print

✓ The authors report a patient with bilateral papillomas of the choroid plexus of the lateral ventricles with documentation of cerebrospinal fluid (CSF) hypersecretion causing hydrocephalus. Special attention is given to the large volume of CSF produced by these tumors (removal of one tumor reduced CSF outflow by one-half) and to the fact that CSF diversion was not required after both tumors were removed. Since tumor removal alone was sufficient to stop the progression of hydrocephalus, we feel that this case supports the concept that elevated CSF production by itself is sufficient to cause hydrocephalus in patients with papillomas of the choroid plexus.

Resistance to nitrofurantoin is an indicator of extensive drug-resistant (XDR) Enterobacteriaceae

2021 ◽  
Vol 70 (4) ◽  
Author(s):  
Balaram Khamari ◽  
Prakash Kumar ◽  
Bulagonda Eswarappa Pradeep
Keyword(s):  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Treatment Options ◽  
Strong Association ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Content Type ◽  
Link Type

Introduction. Nitrofurantoin is one of the preferred antibiotics in the treatment of uropathogenic multidrug-resistant (MDR) infections. However, resistance to nitrofurantoin in extensively drug-resistant (XDR) bacteria has severely limited the treatment options. Gap statement. Information related to co-resistance or collateral sensitivity (CS) with reference to nitrofurantoin resistant bacteria is limited. Aim. To study the potential of nitrofurantoin resistance as an indicator of the XDR phenotype in Enterobacteriaceae . Methods. One hundred (45 nitrofurantoin-resistant, 21 intermediately resistant and 34 nitrofurantoin-susceptible) Enterobacteriaceae were analysed in this study. Antibiotic susceptibility testing (AST) against nitrofurantoin and 17 other antimicrobial agents across eight different classes was performed by using the Vitek 2.0 system. The isolates were screened for the prevalence of acquired antimicrobial resistance (AMR) and efflux pump genes by PCR. Results. In total, 51 % of nitrofurantoin-resistant and 28 % of intermediately nitrofurantoin resistant isolates exhibited XDR characteristics, while only 3 % of nitrofurantoin-sensitive isolates were XDR (P=0.0001). Significant co-resistance was observed between nitrofurantoin and other tested antibiotics (β-lactam, cephalosporin, carbapenem, aminoglycoside and tetracycline). Further, the prevalence of AMR and efflux pump genes was higher in the nitrofurantoin-resistant strains compared to the susceptible isolates. A strong association was observed between nitrofurantoin resistance and the presence of bla PER-1, bla NDM-1, bla OXA-48, ant(2) and oqxA-oqxB genes. Tigecycline (84 %) and colistin (95 %) were the only antibiotics to which the majority of the isolates were susceptible. Conclusion. Nitrofurantoin resistance could be an indicator of the XDR phenotype among Enterobacteriaceae , harbouring multiple AMR and efflux pump genes. Tigecycline and colistin are the only antibiotics that could be used in the treatment of such XDR infections. A deeper understanding of the co-resistance mechanisms in XDR pathogens and prescription of AST-based appropriate combination therapy may help mitigate this problem.

The effect of dexamethasone on the rate of formation of cerebrospinal fluid in the monkey

1974 ◽  
Vol 41 (5) ◽  
pp. 550-554 ◽  
Author(s):  
Albert N. Martins ◽  
Archimedes Ramirez ◽  
Lewis S. Solomon ◽  
G. Michael Wiese
Keyword(s):  
Formation Rate ◽  
Therapeutic Benefit ◽  
Intravenous Dose ◽  
Control Groups ◽  
Perfusion Technique ◽  
Content Type ◽  
Ventriculocisternal Perfusion ◽  
And Control ◽  
Csf Formation Rate ◽  
Fine Print

✓ The standard ventriculocisternal perfusion technique was used to determine what effect a single large intravenous dose of dexamethasone would have on CSF formation rate in the rhesus monkey over a 4-hour period. Three monkeys received 0.15 mg/kg, four received 0.4 mg/kg and five served as the untreated controls. With time, CSF formation rates decreased in both treated and control groups. The magnitude of the decrease in the treated and untreated controls did not differ significantly. We conclude that the therapeutic benefit of dexamethasone for intracranial spatial decompensation derives from a mechanism of action that leaves the rate of CSF formation unchanged.

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