Role of estrogen deficiency in the formation and progression of cerebral aneurysms. Part I: experimental study of the effect of oophorectomy in rats

2005 ◽  
Vol 103 (6) ◽  
pp. 1046-1051 ◽  
Author(s):  
Mohammad A. Jamous ◽  
Shinji Nagahiro ◽  
Keiko T. Kitazato ◽  
Junichiro Satomi ◽  
Koichi Satoh
Keyword(s):  
Cerebral Aneurysm ◽  
Cerebral Aneurysms ◽  
Bilateral Oophorectomy ◽  
Gelatinase Activity ◽  
Content Type ◽  
Group Iii ◽  
Group I ◽  
Group Ii ◽  
Fine Print

Object. Estrogen has been shown to play a central role in vascular biology. Although it may exert beneficial vascular effects, its role in the pathogenesis of cerebral aneurysms remains to be determined. To elucidate the role of hormones further, the authors examined the effects of bilateral oophorectomy on the formation and progression of cerebral aneurysms in rats. Methods. Forty-five female, 7-week-old Sprague—Dawley rats were divided into three equal groups. Group I consisted of intact rats (controls). To induce cerebral aneurysms, the animals in Groups II and III were subjected to ligation of the right common carotid and bilateral posterior renal arteries. One month later, the rats in Group II underwent bilateral oophorectomy. Three months after the experiment began all animals were killed and cerebral vascular corrosion casts were prepared and screened for cerebral aneurysms by using a scanning electron microscope. Plasma was used to determine the level of estradiol and the gelatinase activity. Hypertension developed in all rats except those in the control group. The estradiol level was significantly lower in Group II than in the other groups (p < 0.01). The incidence of cerebral aneurysm formation in Group II (60%) was three times higher than that in Group III (20%), and the mean size of aneurysms in Group II (76 ± 27 µm, mean ± standard deviation) was larger than that in Group III (28 ± 4.6 µm) (p < 0.05). No aneurysm developed in control animals (Group I), and there was no significant difference in plasma gelatinase activity among the three groups. Conclusions. The cerebral aneurysm model was highly reproducible in rats. Bilateral oophorectomy increased the susceptibility of rats to aneurysm formation, indicating that hormones play a role in the pathogenesis of cerebral aneurysms.

Effect of initially limited resuscitation in a combined model of fluid-percussion brain injury and severe uncontrolled hemorrhagic shock

2000 ◽  
Vol 93 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Susan A. Stern ◽  
Brian J. Zink ◽  
Michelle Mertz ◽  
Xu Wang ◽  
Steven C. Dronen
Keyword(s):  
Brain Injury ◽  
Physiological Parameters ◽  
Content Type ◽  
Group Iii ◽  
Fluid Percussion ◽  
Group I ◽  
Group Ii ◽  
Goal Map ◽  
Uncontrolled Hemorrhage ◽  
Fine Print

Object. Studies of isolated uncontrolled hemorrhage have indicated that initial limited resuscitation improves survival. Limited resuscitation has not been studied in combined traumatic brain injury and uncontrolled hemorrhage. In this study the authors evaluated the effects of limited resuscitation on outcome in combined fluid-percussion injury (FPI) and uncontrolled hemorrhage.Methods. Twenty-four swine weighing 17 to 24 kg each underwent FPI (3 atm) and hemorrhage to a mean arterial pressure (MAP) of 30 mm Hg in the presence of a 4-mm aortic tear. Group I (nine animals) was initially resuscitated to a goal MAP of 60 mm Hg; Group II (nine animals) was resuscitated to a goal MAP of 80 mm Hg; and Group III (control; six animals) was not resuscitated. After 60 minutes, the aortic hemorrhage was controlled and the animals were resuscitated to baseline physiological parameters and observed for 150 minutes.Mortality rates were 11%, 50%, and 100% for Groups I, II, and III, respectively (Fisher's exact test; p = 0.002). The total hemorrhage volume was greater in Group II (69 ± 32 ml/kg), as compared with Group I (41 ± 18 ml/kg) and Group III (37 ± 3 ml/kg) according to analysis of variance (p < 0.05). In surviving animals, cerebral perfusion pressure, cerebral blood flow (CBF), cerebral venous O2 saturation (ScvO2), and cerebral metabolic rate of O2 did not differ among groups. Although CBF was approximately 50% of baseline during the period of limited resuscitation in Group I, ScvO2 remained greater than 60%, and arteriovenous O2 differences remained within normal limits.Conclusions. In this model of FPI and uncontrolled hemorrhage, early aggressive resuscitation, which is currently recommended, resulted in increased hemorrhage and failure to optimize cerebrovascular parameters. In addition, a 60-minute period of moderate hypotension (MAP = 60 mm Hg) was well tolerated and did not compromise cerebrovascular hemodynamics, as evidenced by physiological parameters that remained within the limits of cerebral autoregulation.

Genoprotective role of vitamin E and selenium in rabbits anaesthetized with sevoflurane

2004 ◽  
Vol 23 (8) ◽  
pp. 413-419 ◽  
Author(s):  
Cetin Kaymak ◽  
Ela Kadioglu ◽  
Hulya Basar ◽  
Semra Sardas
Keyword(s):  
Dna Damage ◽  
Vitamin E ◽  
Comet Assay ◽  
Antioxidant Supplementation ◽  
Group Iii ◽  
Sevoflurane Anaesthesia ◽  
Group I ◽  
The Mean ◽  
Group Ii

In this study, genotoxic effects of repeated sevoflurane anaesthesia were investigated in rabbits with or without antioxidant supplementation. Twenty-one New Zealand male rabbits were included in the study and randomized into three groups as: placebo treated (Group I), vitamin E supplemented (Group II) and selenium supplemented (Group III). Vitamin E and selenium were given intraperitoneally for 15 days before anaesthesia treatment. Anaesthesia was administered using 3% sevoflurane in 4 L/min oxygen for a 3-hour period and continued for 3 days. Blood samples were collected before anaesthesia (Sample 1), after the first, second and third days of sevoflurane administration (Sample 2, Sample 3 and Sample 4 respectively) and the last samples were taken 5 days after the last sevoflurane administration (Sample 5). Genotoxic damage was examined using the comet assay. The degree of damage is assessed by grading the cells into three categories of no migration (NM), low migration (LM) and high migration (HM) depending on the fraction of DNA pulled out into the tail under the influence of the electric field. The number of comets in each sample was calculated (1 × number of comets in category NM + 2 × number of comets in category LM + 3 ×number of comets in category HM) and expressed as the total comet score (TCS), which summarizes the damage frequencies. In Group I, a significant increase in the mean TCSs was observed for Samples 3 and 4 as compared with Sample 1. However, there were no significant differences between Samples 1, 2 and 5. The mean TCS of Sample 4 was significantly higher than Sample 1, 2 and 3 in Group II. Group III demonstrated no significant mean TCSs for any experimental conditions. Statistical differences were also observed between the groups with significant P values. This experimental study points out the presence of DNA damage with repeated sevoflurane anaesthesia and the genoprotective role of antioxidant supplementation on DNA damage in mononuclear leukocytes of rabbits by highly sensitive comet assay.

Endothelin effects in isolated, perfused lamb lungs: role of cyclooxygenase inhibition and vasomotor tone

1991 ◽  
Vol 261 (2) ◽  
pp. H443-H450 ◽  
Author(s):  
H. Toga ◽  
J. Usha Raj ◽  
R. Hillyard ◽  
B. Ku ◽  
J. Anderson
Keyword(s):  
Vasomotor Tone ◽  
Cyclooxygenase Inhibition ◽  
Group Iii ◽  
Group I ◽  
Before And After ◽  
Pulmonary Arterial ◽  
Group Ii ◽  
Sites Of Action ◽  
Arteries And Veins

We have determined the sites of action of endothelin-1 (ET) in the lamb pulmonary circulation. The influence of cyclooxygenase inhibition and baseline vasomotor tone on ET effects was also studied. Lungs of 14 lambs (6-9 wk of age, 12.1 +/- 0.6 kg body wt) were isolated and perfused with blood. Group I lungs (n = 5) were untreated, group II lungs (n = 5) were treated with indomethacin to inhibit cyclooxygenase, and group III lungs (n = 4) were treated with indomethacin and a thromboxane A2 analogue, U-46619, to elevate vasomotor tone. All lungs were perfused with constant flow in zone 3, with left atrial and airway pressures being 8 and 6 cmH2O, respectively. We measured pulmonary arterial pressure and, by the micropuncture servo-null method, pressures in 20- to 50-microns diameter subpleural venules, both before and after each dose of ET was infused (50, 100, 250, and 500 ng/kg). Group I lungs, with high baseline vasomotor tone, exhibited a biphasic response to ET; 50-100 ng/kg of ET dilated both arteries and veins, whereas 500 ng/kg of ET constricted both arteries and veins. In group II lungs with low vasomotor tone, all doses of ET caused constriction of arteries only. In group III lungs (indomethacin treated with elevated vasomotor tone), 50-100 ng/kg of ET caused dilation of arteries and veins, whereas 500 ng/kg of ET induced constriction, this time only in arteries. We conclude that ET has both dilator and constrictor effects in arteries and veins of isolated, perfused lamb lungs. ET-induced arterial and venous dilation is dependent on initial vasomotor tone but not on cyclooxygenase metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The prognostic role of inflammatory markers in COVID 19 patients – A retrospective analysis.

2021 ◽  
Author(s):  
Shivkumar Gopalakrishnan ◽  
sangeetha kandasamy ◽  
S.Malini ◽  
S.Peer Mohamed ◽  
k.velmurugan
Keyword(s):  
Inflammatory Markers ◽  
Severe Disease ◽  
Radiation Hazard ◽  
P Value ◽  
Binary Logistic Regression Analysis ◽  
Group Iii ◽  
Group I ◽  
Group Ii ◽  
D Dimer

Abstract Background. Approximately 5% of COVID-19 patients suffer near fatal disease. Clinical and radiologic features may predict severe disease albeit with limited specificity and radiation hazard. Laboratory biomarkers are eyed as simple, specific and point of care triage tools to optimize management decisions.This study aimed to study the role of inflammatory markers in prognosticating COVID-19 patients.Methodology. A hospital based retrospective study was conducted on COVID-19 adult inpatients classified into three groups as mild disease-recovered [Group I], severe disease-recovered [Group II] and dead [Group III]. Categorical outcomes were compared using Chi square test. Univariate binary logistic regression analysis was performed to test the association between the explanatory and outcome variables. Unadjusted OR along with 95% CI was calculated. The utility of lab parameters (Ferritin, LDH, D dimer, N/L ratio and PLT/L ratio) in predicting severity of COVID-19 was assessed by Receiver Operative Curve (ROC) analysis. P value < 0.05 was considered statistically significant.Results. The mean age was 49.32 +/- 17.1 years. Among study population, 378 were Group I, 66 Group II, and 56 Group III. Median levels of Ferritin among the 3 groups were 62ng/mL, 388.50 ng/mL and 1199.50 ng/mL. Median value of LDH were 95U/L, 720 and 982.50(p <0.001). D-dimer values of 3 groups were 23.20ng/mL, 104.30 ng/mL and 197.10 ng/mL (p <0.001). CRP done qualitatively was positive in 2 (0.53%), 30 (45.45%) and 53 (94.64%) of patients. The odds of patients suffering severe COVID-19 rose with rising values of ferritin, LDH and D-dimer [unadjusted OR 1.007, 1.004 &1.020]Conclusion. One time measurement of serum ferritin, LDH, D-dimer and CRP is promising to predict outcomes for COVID 19 inpatients. Single qualitative CRP was equally good but more cost effective than quantitative CRP. The most specific combination was NLR, Lymphocyte percentage and D-dimer levels done between 7th – 10th day of symptoms.

Microsurgical C-2 ganglionectomy for chronic intractable occipital pain

1998 ◽  
Vol 89 (3) ◽  
pp. 359-365 ◽  
Author(s):  
Andres M. Lozano ◽  
Graham Vanderlinden ◽  
Robert Bachoo ◽  
Peter Rothbart
Keyword(s):  
Axonal Regeneration ◽  
Excellent Result ◽  
Spontaneous Pain ◽  
Content Type ◽  
Group I ◽  
Experienced Pain ◽  
Pain Outcome ◽  
Group Ii ◽  
Fine Print

Object. The authors evaluated the effectiveness of microsurgical C-2 ganglionectomy in 39 patients with medically refractory chronic occipital pain. In this procedure the neurons transmitting sensory inputs from the occiput are removed and, unlike peripheral nerve ablation, axonal regeneration is not possible. Methods. The patients in this series had symptoms for 1 to 43 years. In 22 patients the occipital pain was caused by trauma; in 17 patients the pain was spontaneous. Pain relief failed in 17 patients who had undergone a previous occipital neurectomy or C-2 rhizolysis. Twenty-three patients experienced pain that was described as shocklike, electric, shooting, jabbing, stabbing, sharp, or exploding (Group I). Eight patients described their pain as dull, pounding, aching, throbbing, or pressurelike (Group II). The patients underwent unilateral or bilateral C-2 open microsurgical ganglionectomies. The postoperative follow-up period ranged from 19 to 48 months. Nineteen patients experienced an excellent result (> 90% reduction in pain). Pain caused by trauma or that described using Group I terms responded best to ganglionectomy (80% good or excellent response). In contrast, the majority of the patients with nontraumatic pain or those described using Group II descriptors did not achieve favorable results. Conclusions. The authors conclude that: 1) patients who suffer from chronic occipital pain after having sustained injury obtain worthwhile benefit from microsurgical C-2 ganglionectomy; 2) patients suffering from migraine, tension, and vascular headaches involving the occipital area are most often not helped by this operation; and 3) terms such as “shock,” “electric,” “shooting,” “jabbing,” and “sharp” used to describe occipital pain predict a favorable pain outcome following a C-2 ganglionectomy.

Exposure of energy-depleted rat trabeculae to low pH improves contractile recovery: role of calcium

1995 ◽  
Vol 268 (4) ◽  
pp. H1510-H1520 ◽  
Author(s):  
C. van Hardeveld ◽  
V. J. Schouten ◽  
A. Muller ◽  
E. T. van der Meulen ◽  
G. Elzinga
Keyword(s):  
Recovery Period ◽  
Muscle Tension ◽  
Low Ph ◽  
Tyrode Solution ◽  
Normal Medium ◽  
Group Iii ◽  
Group I ◽  
Group Ii ◽  
Saving Effect

The beneficial effect of low pH during cardiac ischemia on reperfusion injury has often been attributed to its energy-saving effect due to inhibition of contraction. The role of low pH on Ca2+ accumulation and muscle tension was assessed in energy-depleted tissue by changing the pH of the medium from 7.4 to 6.2 at onset of rigor development during metabolic inhibition (MI), i.e., in the energy-depleted phase. Cytosolic free Ca2+ ([Ca2+]i) and intracellular H+ (pHi) were measured in rat trabeculae at 20 degrees C with fura 2 and 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, respectively, and tension was recorded. The preparations were energy depleted by stimulation at 1 Hz in glucose-free Tyrode solution with 2 mM NaCN. Rigor developed within 20 min, indicating energy depletion. Resting [Ca2+]i was followed during 50 min (group I) or 100 min (group II) of rigor, and recovery was followed for 60 min in glucose-containing Tyrode solution at 0.2-Hz stimulation. Resting [Ca2+]i rose within 50 min (group I) but stabilized in the 50- to 100-min period (group II). All preparations from group I (n = 5) resumed contraction in the recovery period but in group II (n = 10) 70% failed to recover, and [Ca2+]i remained elevated compared with those that recovered. An extracellular pH of 6.2, resulting in similar pHi, from onset of rigor development (group III) led to only a modest rise in [Ca2+]i during the 100-min rigor period, and all preparations resumed contraction after approximately 3 min in normal medium. ATP was very low in all groups at the end of MI but was still significantly lower in group II than in groups I and III. A beneficial energy-sparing effect of low pH during the rigor phase can therefore not be excluded. We conclude that 1) the capacity of trabeculae to recover from MI depends on the time period and magnitude of the [Ca2+]i rise in the energy-depleted phase and 2) low pH in energy-depleted trabeculae protects against Ca overload, improving recovery after normalization of perfusion conditions.

Forearm muscle insulin resistance during hypoglycemia: role of adrenergic mechanisms and hypoglycemia per se

1995 ◽  
Vol 268 (2) ◽  
pp. E248-E254 ◽  
Author(s):  
B. Capaldo ◽  
R. Napoli ◽  
R. Guida ◽  
P. Di Bonito ◽  
S. Antoniello ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Muscle Metabolism ◽  
Mass Effect ◽  
Mean Value ◽  
Adrenergic Stimulation ◽  
Group Iii ◽  
Group I ◽  
Extreme Insulin Resistance ◽  
Group Ii

The forearm perfusion technique was used 1) to quantify the muscle metabolism of glucose and gluconeogenic precursors in response to insulin-induced hypoglycemia and 2) to assess the role of catecholamines and glucose concentration, pe se. Insulin (0.5 mU.kg-1.min-1) was infused for 4 h in three groups of healthy volunteers. In group I (n = 6), blood glucose (BG) was maintained at its basal level (4.5 +/- 0.1 mmol/l). In group II (n = 7), BG was allowed to fall to approximately 3 mmol/l. Group III (n = 6) was similar to group II except that propranolol was infused also. In addition, at 240 min, hypoglycemia was locally corrected by intrabrachial glucose infusion while maintaining the systemic milieu unperturbed. In group I, forearm glucose uptake (FGU) increased from 4.7 +/- 1.3 to a mean value of 37.8 +/- 5.0 mumol.l-1.min-1, whereas in group II it remained unchanged (8.3 +/- 2.0 mumol.l-1.min-1). In group III, propranolol partially prevented the suppression of FGU that increased to 21.6 +/- 5.2 mumol.l-1.min-1 (P < 0.05 vs. group II). Local correction of hypoglycemia normalized the FGU response (36.5 +/- 8.0 mumol.l-1.min-1). Muscle release of lactate, but not of alanine, was slightly higher during hypoglycemia (P = not significant). Forearm blood flow remained unchanged in groups I and III, whereas it increased by approximately 40% in group II (P < 0.05). It is concluded that, during mild hypoglycemia 1) extreme insulin resistance develops in the skeletal muscle, mediated by beta-adrenergic stimulation and reduced glucose mass effect and 2) mobilization of gluconeogenic precursors is only weakly activated.

Failure of third ventriculostomy in the treatment of aqueductal stenosis in children

1999 ◽  
Vol 90 (3) ◽  
pp. 448-454 ◽  
Author(s):  
Giuseppe Cinalli ◽  
Christian Sainte-Rose ◽  
Paul Chumas ◽  
Michel Zerah ◽  
Francis Brunelle ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Aqueductal Stenosis ◽  
Third Ventriculostomy ◽  
Content Type ◽  
Group I ◽  
Endoscopic Guidance ◽  
Group Ii ◽  
Fine Print

Object. The goal of this study was to analyze the types of failure and long-term efficacy of third ventriculostomy in children.Methods. The authors retrospectively analyzed clinical data obtained in 213 children affected by obstructive triventricular hydrocephalus who were treated by third ventriculostomy between 1973 and 1997. There were 120 boys and 93 girls. The causes of the hydrocephalus included: aqueductal stenosis in 126 cases; toxoplasmosis in 23 cases, pineal, mesencephalic, or tectal tumor in 42 cases; and other causes in 22 cases. In 94 cases, the procedure was performed using ventriculographic guidance (Group I) and in 119 cases by using endoscopic guidance (Group II). In 19 cases (12 in Group I and seven in Group II) failure was related to the surgical technique. Three deaths related to the technique were observed in Group I. For the remaining patients, Kaplan—Meier survival analysis showed a functioning third ventriculostomy rate of 72% at 6 years with a mean follow-up period of 45.5 months (range 4 days–17 years). No significant differences were found during long-term follow up between the two groups. In Group I, a significantly higher failure rate was seen in children younger than 6 months of age, but this difference was not observed in Group II. Thirty-eight patients required reoperation (21 in Group I and 17 in Group II) because of persistent or recurrent intracranial hypertension. In 29 patients shunt placement was necessary. In nine patients in whom there was radiologically confirmed obstruction of the stoma, the third ventriculostomy was repeated; this was successful in seven cases. Cine phase-contrast (PC) magnetic resonance (MR) imaging studies were performed in 15 patients in Group I at least 10 years after they had undergone third ventriculostomy (range 10–17 years, median 14.3 years); this confirmed long-term patency of the stoma in all cases.Conclusions. Third ventriculostomy effectively controls obstructive triventricular hydrocephalus in more than 70% of children and should be preferred to placement of extracranial cerebrospinal shunts in this group of patients. When performed using ventriculographic guidance, the technique has a higher mortality rate and a higher failure rate in children younger than 6 months of age and is, therefore, no longer preferred. When third ventriculostomy is performed using endoscopic guidance, the same long-term results are achieved in children younger than 6 months of age as in older children and, thus, patient age should no longer be considered as a contraindication to using the technique. Delayed failures are usually secondary to obstruction of the stoma and often can be managed by repeating the procedure. Midline sagittal T2-weighted MR imaging sequences combined with cine PC MR imaging flow measurements provide a reliable tool for diagnosis of aqueductal stenosis and for ascertaining the patency of the stoma during follow-up evaluation.

Cerebral protection by intermittent reperfusion during temporary focal ischemia in the rat

1996 ◽  
Vol 85 (5) ◽  
pp. 923-928 ◽  
Author(s):  
Carlos A. David ◽  
Ricardo Prado ◽  
W. Dalton Dietrich
Keyword(s):  
Arterial Occlusion ◽  
Focal Ischemia ◽  
Global Ischemia ◽  
Cerebral Injury ◽  
Histopathological Analysis ◽  
Content Type ◽  
Group I ◽  
Group Ii ◽  
Temporary Clipping ◽  
Fine Print

✓ Temporary arterial occlusion has been routinely used as an adjunct in intracranial aneurysm surgery. This has commonly been performed using a protocol of multiple short periods of occlusion alternating with periods of restoration of normal circulation. Recently, the logical basis of this method has come under scrutiny. There is extensive experimental evidence to suggest that repetitive, brief periods of global ischemia may cause more severe cerebral injury than an equivalent single period of global ischemia. Only recently has this issue begun to be addressed with regard to focal ischemia. Hence, despite the common use of temporary clipping, little experimental data are available regarding the ischemic consequences of temporary arterial occlusion with periods of reperfusion versus uninterrupted temporary occlusion. To investigate this issue, a protocol of occlusion/reperfusion that simulates the temporal profile that occurs during surgery was performed in a rat model of focal ischemia. Sixteen anesthetized Sprague—Dawley rats were divided into two groups. The animals in Group I underwent 60 minutes of uninterrupted middle cerebral artery occlusion and the animals in Group II were subjected to six separate 10-minute occlusion periods with 5 minutes of reperfusion between occlusions. Histopathological analysis was performed 72 hours postischemia. Group I had significantly increased mean infarction volumes (50.0 ± 12.1 mm3) compared to Group II (8.7 ± 3.1 mm3) (p = 0.008). Injuries in Group I occurred in both the cortex and striatum, whereas Group II showed only striatal injuries. Furthermore, the extent of the injuries in Group II was less severe, characterized by ischemic neuronal injury rather than frank infarction. The results indicate that intermittent reperfusion is neuroprotective during temporary focal ischemia and support the hypothesis that intermittent reperfusion is beneficial if temporary clipping is required during aneurysm repair.

Changes in CSF pressure after mannitol in patients with and without elevated CSF pressure

1988 ◽  
Vol 69 (6) ◽  
pp. 869-876 ◽  
Author(s):  
Patrick Ravussin ◽  
Mounir Abou-Madi ◽  
David Archer ◽  
René Chiolero ◽  
James Freeman ◽  
...  
Keyword(s):  
Intracranial Hypertension ◽  
Venous Pressure ◽  
Tumor Resection ◽  
Fluid Pressure ◽  
Content Type ◽  
Csf Pressure ◽  
Arterial Blood ◽  
Group I ◽  
Group Ii ◽  
Fine Print

✓ In view of the current concern that rapid infusion of mannitol might initially aggravate intracranial hypertension, the effects of a mannitol infusion on lumbar cerebrospinal fluid pressure (CSFP) were investigated in 49 patients. The studies were performed when the patients were under general anesthesia prior to elective craniotomy for tumor resection or intracerebral aneurysm clipping. The patients were divided into two groups: 24 patients with normal CSFP (Group I, mean CSFP 10.5 mm Hg) and 25 with raised CSFP (Group II, mean CSFP 20.8 mm Hg). Measurements of CSFP, mean arterial blood pressure (MABP), and central venous pressure (CVP) were made serially during and after the infusion of 20% mannitol (1 gm ⋅ kg−1 infused over a 10-minute interval). In both groups, mannitol infusion provoked a fall in MABP and an increase in CVP. An immediate increase in CSFP was observed in Group II, whereas CSFP increased transiently but significantly in Group I. Analysis of the arterial and venous driving pressures which contribute to CSFP suggests that the transient increase in CSFP after mannitol in Group I was partly due to the increase in CVP. The presence of intracranial hypertension may thus alter the CSFP response to arterial and venous pressure changes. Cerebral blood volume (CBV) was measured in dogs in a separate study analogous to the human protocol. The CBV increased approximately 25% over control values after mannitol infusion both in the normal animals and in those with CSFP raised by an epidural balloon. The response of the CSFP to mannitol infusion differed between both groups in a fashion similar to that observed in the human subjects. Thus, differences in CBV changes after mannitol do not account for the difference in CSFP response between normal subjects and those with raised CSFP.

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