bluuebunny/crossref_metadata_2025_split huggingface dataset:
The proliferative potential of human pituitary tumors in situ
Authors: Nagashima Tadashi , Murovic Judith A. , Hoshino Takao , Wilson Charles B. , DeArmond Stephen J. 
Published: May 2009

✓ At the start of transsphenoidal microsurgery for removal of various types of pituitary adenomas, 21 patients received a 1-hour intravenous infusion of 5-bromodeoxyuridine (BUdR, 200 mg/sq m) to label tumor cells in the deoxyribonucleic acid (DNA) synthesis phase (S-phase). Excised tumor specimens were fixed in 70% ethanol and stained by the indirect peroxidase method using anti-BUdR monoclonal antibody as the first antibody. The percentage of BUdR-labeled cells, or S-phase fraction, was calculated for each specimen. The S-phase fraction was less than 0.1% in nine cases, 0.1% to 0.5% in seven, and greater than 0.5% in five. Except in two cases of Nelson's syndrome, in which it was greater than 1%, the S-phase fraction did not correlate with any other variable, including patient age, tumor size, or the duration of signs and symptoms.
The small S-phase fraction of most of the pituitary adenomas correlates well with the clinical behavior of these tumors, which grow much more slowly than other kinds of brain tumors such as gliomas. However, the S-phase fractions varied by as much as one order of magnitude. The higher S-phase fractions may reflect aggressive and invasive growth. These results indicate that immunohistochemical studies of cell kinetics using BUdR and anti-BUdR monoclonal antibodies may provide information about the biological characteristics of pituitary adenomas which could lead to the design of appropriate treatment regimens (including surgery, radiation therapy, and chemotherapy) for individual patients.
Effect of naloxone on cerebral perfusion and cardiac performance during experimental cerebral ischemia
Authors: Hariri Robert J. , Supra Elizabeth L. , Roberts John Paul , Lavyne Michael H. 
Published: May 2009

✓ Transient global cerebral ischemia (TGI) was induced in awake rats using the “four-vessel” occlusion model of Pulsinelli and Brierley. Blood pressure, arterial blood gases, cerebral blood flow, and cardiac output were measured during the acute (up to 2 hours) and chronic (2 to 72 hours) postischemic time periods. Coincident with the onset of TGI, cardiac output and caudate blood flow were depressed. The former returned to baseline within 30 minutes after the conclusion of TGI, and the latter progressed to hyperemia at 12 hours (81.8 ± 4.9 vs 68.6 ± 3.9 ml/min/100 gm tissue (mean ± standard error of the mean)) and oligemia at 72 hours (45.5 ± 4.8 ml/min/100 gm tissue) post-TGI in the untreated control rats. Arterial blood gases and blood pressure were unchanged. Naloxone (1 mg/kg) given at the time of TGI or as late as 60 minutes post-TGI and every 2 hours thereafter for 24 hours or bilateral cervical vagotomy prevented the depression in cardiac output and blocked the hyperemic-oligemic cerebral blood flow pattern that was predictive of stroke in this rat model.
Changes in cardiac output after TGI in this model appear to be mediated by parasympathetic pathways to the heart from the brain stem. Opiate receptor blockade probably blocks endogenous opioid peptide stimulation of these brain-stem circulatory centers, which results in inhibition of parasympathetic activity and improvement in cardiac output. The usefulness of naloxone in the treatment of experimental stroke may be a function of its ability to improve cerebral perfusion in pressure-passive cerebrovascular territories. Variations in cardiac output during experimental stroke may explain the dissimilar responses to naloxone treatment reported by other investigators of experimental stroke.
Nuclear magnetic resonance imaging and spectroscopy in experimental brain edema in a rat model
Authors: Bederson Joshua B. , Bartkowski Henry M. , Moon Kirkland , Halks-Miller Meredith , Nishimura Merry C. , Brant-Zawadski Michael , Pitts Lawrence H. 
Published: May 2009

✓ Many aspects of the use of high-resolution nuclear magnetic resonance (NMR) imaging in the examination of brain edema have not been fully explored. These include the quantitation of edema fluid, the ability to distinguish between various types of edema, and the extent to which tissue changes other than a change in water content can affect NMR relaxation times. The authors have compared NMR relaxation times obtained by both in vivo magnetic resonance imaging (MRI) and in vitro NMR spectroscopy of brain-tissue samples from young adult rats with cold lesions, fluid-percussion injury, hypoxic-ischemic injury, bacterial cerebritis, and cerebral tumor. Changes in relaxation times were compared with changes in brain water content, cerebral blood volume, and the results of histological examination.
In general, both in vivo and in vitro longitudinal relaxation times (T1) and transverse relaxation times (T2) were prolonged in the injured hemispheres of all experimental groups. Water content of tissue from the injured hemispheres was increased in all groups. A linear correlation between T2 (but not T1) and water content was found. Changes in the values of T1 and T2 could be used to distinguish tumor from cold-injured tissue. Cerebral blood volume was reduced in the injured hemispheres and correlated inversely with prolongation of T1 and T2. The results of this study suggest that, in a clinical setting, prolongation of T2 is a better indicator of increased water content than prolongation of T1, yet quantitation of cerebral edema based solely upon prolongation of in vivo or in vitro T1 and T2 should be undertaken with caution.
Assessment of nutritional requirements of head-injured patients
Authors: Clifton Guy L. , Robertson Claudia S. , Choi Sung C. 
Published: May 2009

✓ A nomogram is presented for estimation of energy expenditure at the bedside in comatose patients during the first 2 weeks after brain injury. In analysis of 312 days of energy expenditure in 57 patients, a combination of Glasgow Coma Scale (GCS) score, heart rate (HR), and days since injury (DSI) was found with multiple regression analysis to provide good prediction of resting metabolic expenditure (RME) according to the following relationship: %RME = 152 − 14(GCS score) + 0.4(HR) + 7(DSI) (n = 111, r = 0.7, p < 0.001). In non-comatose patients, predictive ability was less strong due to inability to measure truly rested values, but HR and GCS score could be used to predict energy expenditure by this relationship: %RME = 90 − 3 (GCS score) + 0.9 (HR) (n = 135, r = 0.47, p < 0.001). In six patients, paralysis was found to decrease energy expenditure to between 100% and 125% of expected. Movement or stimulation had little effect on energy expenditure in patients who could localize stimuli but increased rested values by 20% in posturing patients.
Analysis of fasted balance periods of nitrogen excretion in 22 patients based on 273 days of measurement showed a significant relationship between creatinine-height index (an index of muscle mass) and nitrogen excretion, but no relationship between nitrogen excretion and weight, temperature, and RME. Levels of retention of nitrogen with feeding could not be predicted by any of these variables. Feeding of the individual comatose patient is best guided at present by estimation of energy expenditure using a nomogram and periodic measurement of urinary nitrogen excretion.
Cerebral effects of hypocapnia plus nitroglycerin-induced hypotension in dogs
Authors: Artru Alan A. , Wright Kim , Colley Peter S. 
Published: May 2009

✓ This study examined the effect of hypocapnia (PaCO2 20 mm Hg) on cerebral metabolism and the electroencephalogram (EEG) findings in 12 dogs during nitroglycerin (NTG)-induced hypotension. Previous studies suggest that NTG is a more potent cerebral vasodilator than sodium nitroprusside or trimethaphan. It was speculated that combining hypocapnia with NTG-induced hypotension would cause less disturbance of cerebral metabolism and the EEG than the disturbances previously reported when hypocapnia was combined with hypotension induced by sodium nitroprusside or trimethaphan.
All 12 dogs were examined at 1) normocapnia with normotension; 2) hypocapnia with normotension; and 3) hypocapnia combined with NTG-induced hypotension to mean arterial blood pressure (MABP) levels of 60, 50, and 40 mm Hg. In six dogs the cerebral metabolic rate of oxygen was determined, and the EEG was evaluated using compressed spectral analysis. Brain tissue metabolites were calculated in the other six dogs. During normotension, hypocapnia caused no deterioration of cerebral metabolism or of the EEG. Hypocapnia combined with NTG-induced hypotension caused a decrease of the power of the α and β2 spectra of the EEG at MABP's of 60 mm Hg or less. At an MABP of 40 mm Hg, brain tissue phosphocreatine and the cerebral energy charge decreased, while the brain tissue lactate:pyruvate ratio increased. Thirty minutes after restoration of normocapnia with normotension, cerebral metabolites returned to initial values, but the power of the EEG α and β2 spectra was decreased compared to baseline values.
The cerebral metabolic disturbances and EEG alterations seen here with hypocapnia plus NTG-induced hypotension were similar to those previously reported with hypocapnia plus sodium nitroprusside-induced hypotension, and less than those previously reported with hypocapnia plus trimethaphan-induced hypotension. For hyperventilated patients, administration of NTG may be a better hypotensive treatment than trimethaphan, but similar in effect to sodium nitroprusside.
Hormonal manipulation of meningiomas in vitro
Authors: Olson Jeffrey J. , Beck David W. , Schlechte Janet , Loh Pao-Min 
Published: May 2009

✓ Speculation that meningiomas are subject to endocrine influence is supported by their higher incidence in women, reports of exacerbation of symptoms during pregnancy, and the discovery that these tumors harbor progesterone- and estrogen-binding proteins. To evaluate if these properties could be exploited therapeutically, specimens from three convexity meningiomas were used for estrogen- and progesterone-binding protein assays and establishment of tissue cultures. Each tumor (designated A, B, and C, respectively) was grown in experimental media containing 7.5 × 10−5 to 10−12 M 17β-estradiol, 2.5 × 10−4 to 10−12 M progesterone, 10−7 to 10−9 M tamoxifen (an estrogen antagonist), and 10−6 to 10−10 M RU486 (a progesterone antagonist). After incubation, cell growth was compared to control preparations by counting the meningioma cells present in each medium.
Tumors A, B, and C contained estrogen-binding proteins of 8.45, 13.6, and 26.9 fmol/mg cytosol protein and progesterone-binding proteins of 210, 130, and 126 fmol/mg cytosol protein, respectively. The media containing 17β-estradiol and progesterone caused 21% to 36% growth stimulation in Tumors A and B. In Tumor A, the addition of tamoxifen stimulated growth by 35%, while it caused only transient stimulation in Tumor B and had no effect on Tumor C. RU486, the progesterone antagonist, caused inhibition of cell growth in all three tumors, ranging from 18% to 36%.
These data suggest that selected meningiomas are subject to hormonal influence in vitro. The inhibition of meningioma growth in vitro by the antiprogesterone, RU486, has not been previously reported, and serves to encourage further development of alternative modes of therapy for recurrent and unresectable meningiomas.
Neurotransmitters in the cerebral cortex
Authors: Jones Edward G. 
Published: May 2009

✓ This article surveys the conventional neurotransmitters and modulatory neuropeptides that are found in the cerebral cortex and attempts to place them into the perspective of both intracortical circuitry and cortical disease. The distribution of these substances is related, where possible, to particular types of cortical neuron or to afferent or efferent fibers. Their physiological actions, where known, on cortical neurons are surveyed, and their potential roles in disease states such as the dementias, epilepsy, and stroke are assessed.
Conventional transmitters that occur in afferent fibers to the cortex from brain-stem and basal forebrain sites are: serotonin, noradrenaline, dopamine, and acetylcholine. All of these except dopamine are distributed to all cortical areas: dopamine is distributed to frontal and cingulate areas only. The transmitter in thalamic afferent systems is unknown.
Gamma aminobutyric acid (GABA) is the transmitter used by the majority of cortical interneurons and has a profound effect upon the shaping of receptive field properties. The vast majority of the known cortical peptides are found in GABAergic neurons, and the possibility exists that they may act as trophic substances for other neurons. Levels of certain neuropeptides decline in cases of dementia of cortical origin. Acetylcholine is the only other known transmitter of cortical neurons. It, too, is contained in neurons that also contain a neuropeptide.
The transmitter(s) used by excitatory cortical interneurons and by the efferent pyramidal cells is unknown, but it may be glutamate or aspartate. It is possible that excitotoxins released in anoxic disease of the cortex may produce damage by acting on receptors for these or related transmitter agents.
Subtle deterioration in shunted childhood hydrocephalus
Authors: Fried Arno , Shapiro Kenneth 
Published: May 2009

✓ Eighteen hydrocephalic children who presented with subtle deterioration when their shunts malfunctioned were studied during shunt revision by means of the pressure-volume index (PVI) technique. Bolus manipulation of cerebrospinal fluid (CSF) was used to determine the PVI and the resistance to the absorption of CSF (Ro). Ventricular size was moderately to severely enlarged in all the children. Steady-state intracranial pressure (ICP) at the time of shunt revision was 17.5 ± 7.3 mm Hg (range 8 to 35 mm Hg). Pressure waves could not be induced by bolus injections in the 8- to 35-mm Hg range of ICP tested. The mean ± standard deviation (SD) of the predicted normal PVI for this group was 18.5 ± 2.7 ml. The mean ± standard error of the mean of the measured PVI was 35.5 ± 2.1 ml, which represented a 187% ± 33% (± SD) increase in volume-buffering capacity (p < 0.001). The ICP did not fall after bolus injections in three children, so that the Ro could not be measured. In the remaining 15 patients, Ro increased linearly as a function of ICP (r = 0.74, p < 0.001). At ICP's below 20 mm Hg, Ro ranged from 2.0 to 5.0 mm Hg/ml/min, but increased to as high as 21 mm Hg/ml/min when ICP was above 20 mm Hg.
This study documents that subtle deterioration in shunted hydrocephalic children is accompanied by abnormally compliant pressure-volume curves. These children develop ventricular enlargement and neurological deterioration without acute episodic pressure waves. The biomechanical profile of this group differs from other children with CSF shunts.
RG2 glioma growth in rat cerebellum after subdural implantation
Authors: Krajewski Stanislaw , Kiwit Jürgen C. W. , Wechsler Wolfgang 
Published: May 2009

✓ The nitrosourea-induced rat glioma clone RG2 was tested for its capacity to form multicellular tumor spheroids (MTS's). Resulting spheroids were investigated by light and electron microscopy with regard to their proliferation patterns and morphological features. Using microsurgical techniques and avoiding mechanical injury of the brain tissue, the authors successfully transplanted avascular MTS's under the dura of the cerebellum, above the vermis, in 43 adult syngeneic Fischer CD rats. The rate of tumor establishment was 93%, and the tumors that were solid and spheroid in shape grew exponentially. Neovascularization could be observed at 3 days after implantation, and invasion of the cerebellum occurred by 3 to 5 days. Neurological deterioration, including ataxia, impairment of walking, and apathy, could be observed after 10 days. The mean survival time was approximately 16 days. The subdural cerebellar tumors were studied by histological techniques, and two morphometric methods were applied to check the growth of implanted spheroids. All tumors were deeply stained with the Evans blue dye-albumin complex, demonstrating disturbance of the blood-brain barrier.
The easy accessibility of the cerebellar vermis in rats, the microsurgical implantation of glioma spheroids under the dura avoiding nerve tissue disruption, and the high percentage of reproducible establishment of tumors favor this experimental brain-tumor model. This should be an excellent model for study of experimental therapies.
Effects of steroids and nonsteroid anti-inflammatory agents on vascular permeability in a rat glioma model
Authors: Reichman Howard R. , Farrell Catherine L. , Del Maestro Rolando F. 
Published: May 2009

✓ Cerebral edema produced by brain tumors is clinically and experimentally reduced by steroid therapy. Nonsteroid anti-inflammatory drugs (NSAID's) which have been used to treat non-neural inflammation and swelling have not been evaluated for their ability to affect edema produced by brain tumors. The authors have used the rat C6 glioma spheroid implantation model to compare the effects of two steroids (dexamethasone and methylprednisolone) and two NSAID's (ibuprofen and indomethacin) on protein extravasation caused by intracranial gliomas. Evans blue dye was used as a marker for serum albumin extravasation. The concentration of Evans blue dye was measured in the tumor and peritumoral and contralateral brain tissue 1 hour after intravenous injection.
Extravasation of Evans blue dye within the tumor was decreased in all treatment groups when compared to placebo-injected control animals. The differences between the control specimens and those treated with dexamethasone, methylprednisolone, and indomethacin were highly significant (p < 0.005). The Evans blue staining was also decreased in the peritumoral and contralateral brain. These results indicate that NSAID's compare favorably with steroids in diminishing tumor-induced protein extravasation. It is suggested that NSAID's may prove to be beneficial in clinical instances used either in conjunction with steroid therapy or alone when steroids are contraindicated.
Aneurysm of the ICA petrous segment treated by balloon entrapment after EC-IC bypass
Authors: McGrail Kevin M. , Heros Roberto C. , Debrun Gerard , Beyerl Brian D. 
Published: May 2009

✓ A 44-year-old man experienced the sudden onset of horizontal diplopia and hemifacial numbness. Arteriography demonstrated a left intrapetrous carotid artery aneurysm. The patient was successfully treated with a left superficial temporal artery to middle cerebral artery bypass followed by balloon entrapment of the aneurysm.
There have been at least 40 previously reported cases of aneurysms of the petrous portion of the carotid artery. These aneurysms can be mycotic, traumatic, or developmental in origin. They can present with massive otorrhagia or epistaxis from acute rupture or with decreased hearing and paresis of the fifth through eighth cranial nerves and, less frequently, of the ninth, 10th, and 12th cranial nerves caused by direct pressure. They can also produce pulsatile tinnitus, and sometimes they are discovered as a retrotympanic vascular mass during otological examination. The treatment of choice is carotid artery occlusion. Trapping of the aneurysm by detachable balloons eliminates immediately the risk of hemorrhage, offers the possibility of test occlusion of the internal carotid artery with the patient awake prior to permanent occlusion, and should also reduce the risk of thromboembolism. It should be preceded by a bypass procedure when preliminary evaluation indicates that the patient will not tolerate internal carotid artery occlusion.
Evaluation of cerebral AVM's using transcranial Doppler ultrasound
Authors: Lindegaard Karl-Fredrik , Grolimund Peter , Aaslid Rune , Nornes Helge 
Published: May 2009

✓Blood flow velocities in basal cerebral arteries were recorded noninvasively in 28 patients with cerebral arteriovenous malformations (AVM's) and were correlated with the angiographic findings. In normal arteries remote from the AVM, flow velocities ranged from 44 to 94 cm/sec (median 65 cm/sec) with pulsatility indexes from 0.65 to 1.10 (median 0.87). This is consistent with findings in normal individuals. Arteries feeding the AVM's were identified by the high flow velocities (ranging from 75 to 237 cm/sec, median 124 cm/sec). The pulsatility index ranged from 0.22 to 0.74 (median 0.48). The difference of these results from findings in normal remote arteries was highly significant (p < 0.001). Hyperventilation tests illustrated the hemodynamic difference between an AVM and normal cerebrovascular beds.
Flow velocity measurements permitted noninvasive diagnosis of AVM's in 26 of the 28 patients. Furthermore, the identification of individual feeding arteries permitted good definition of the anatomical localization of individual AVM's. Flow velocity measurements combined with computerized tomography scans are useful in the diagnosis of AVM's. With the feeding artery's configuration identified on angiography, flow velocity measurements permit a new insight into the “hemodynamic dimension” of an AVM and its possible effects on adjacent normal brain-tissue perfusion in the individual patient.
Study of the posterior circulation in moyamoya disease
Authors: Miyamoto Susumu , Kikuchi Haruhiko , Karasawa Jun , Nagata Izumi , Ihara Ikuo , Yamagata Sen 
Published: May 2009

✓ The involvement of the posterior circulation in moyamoya disease was studied in 178 patients. Forty-three had several types of disturbance such as visual field defect, decreased visual acuity, episodes of blindness, and scintillating scotomata. Most of these symptoms were attributed to occlusive lesions in the posterior circulation. Visual disturbances were seen more often in patients with a juvenile onset than in cases of adult onset.
Superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis and encephalomyosynangiosis (EMS) improved the cerebral perfusion both in the anterior and posterior circulation by redistribution of blood. In most cases, the visual symptoms subsided or were stabilized after STA-MCA anastomosis and EMS. These surgical procedures did not, however, lead to direct revascularization in cases of ischemia in the visual cortex. In five patients with impending blindness, transplantation of the omentum to the occipital lobe led to improved vision.
Surgical anatomy of the arteries of the posterior fossa
Authors: Shrontz Carl , Dujovny Manuel , Ausman James I. , Diaz Fernando G. , Pearce Jeffrey E. , Berman S. Kim , Hirsch Ellyn , Mirchandani Haresh G. 
Published: May 2009

✓ The development of revascularization for vertebrobasilar ischemic events has created a need to identify the best sites at which to perform bypass procedures. Since the occlusive process may selectively affect various levels of the vertebrobasilar tree, sites in different vessels must be used to reestablish flow distal to the area of occlusion. Twenty-seven unfixed human brains were obtained 4 to 8 hours post mortem, and the vertebrobasilar system was injected with polyester resin. Under a surgical microscope the outer diameter, length, and site of origin of major branches were recorded for the following arteries: vertebral, basilar, posterior inferior cerebellar (PICA), anterior inferior cerebellar (AICA), superior cerebellar (SCA), and posterior cerebral (PCA).
The ideal sites for an anastomosis were identified as the pretonsillar segment of the PICA, the second portion of the AICA, the perimesencephalic segment of the SCA, and the perimesencephalic part of the PCA. Based on the anatomical observations reported here, these were the best sites because of their outer diameter, degree of mobility, least number of branches, and frequency of occurrence. Use of two of these arteries, however, may pose potential problems: although the PCA has an ideal outer diameter, it also has numerous branches to the brain stem in its most accessible site in the perimesencephalic area; and the PICA is not consistently present, being found in only 75% of the 27 specimens studied.