bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Early Cover Screw Exposure on Crestal Bone Loss Around Implants: Intraindividual Comparison of Bone Level at Exposed and Non‐Exposed Implants
Authors: Kim Tae‐Hyung , Lee Dong‐Won , Kim Chong‐Kwan , Park Kwang‐Ho , Moon Ik‐Sang
Published: June 2009

Background: The objective of this study was to evaluate the influence of early exposure of the cover screw on crestal bone loss around implants.

Methods: The study population consisted of 19 patients who were treated with dental implants placed using a two‐stage surgical protocol and had early exposed and non‐exposed implants (20 early exposed and 20 non‐exposed implants). The crestal bone loss at exposed and non‐exposed implants in each patient was evaluated with a periapical radiograph taken at the first surgery and at suprastructure insertion using a computerized image‐analysis system. The bone loss was compared using the Wilcoxon signed‐rank test.

Results: The mean crestal bone loss at exposed implants was 0.40 ± 0.53 mm, and it was 0.18 ± 0.26 mm at non‐exposed implants. The Wilcoxon signed‐rank test revealed a statistically significant difference in crestal bone loss between exposed and non‐exposed implants in the same patient (P = 0.02).

Conclusions: The early exposure of the cover screw that results in breakdown of the mucosal seal seems to accelerate early peri‐implant crestal bone loss. Periodic follow‐up after the first surgery may be critical for minimizing the influence of early exposure.
Short‐Term Effects of Non‐Surgical Periodontal Treatment on Plasma Level of Reactive Oxygen Metabolites in Patients With Chronic Periodontitis
Authors: Tamaki Naofumi , Tomofuji Takaaki , Ekuni Daisuke , Yamanaka Reiko , Yamamoto Tatsuo , Morita Manabu
Published: June 2009

Background: Elevated levels of blood reactive oxygen species (ROS) are associated with the severity of periodontitis. Therefore, improvement of periodontitis may result in a decrease in blood ROS. However, it is unclear how periodontal treatment affects blood ROS. Recently, reactive oxygen metabolites (ROMs) were recognized as a useful measure of blood ROS. The aim of this longitudinal study was to investigate the effect of non‐surgical periodontal treatment on plasma ROMs in patients with chronic periodontitis.

Methods: Nineteen subjects with chronic periodontitis (mean age: 46.8 years) were monitored at baseline (prior to scaling and root planing) and 1 and 2 months after therapy. Dental health parameters were evaluated, and plasma was obtained at these time points from patients and controls (19 subjects without periodontitis; mean age: 45.3 years). The plasma ROM level was determined using a spectrophotometric technique.

Results: At baseline, patients with chronic periodontitis had higher plasma ROM level (441.8 ± 71.1 Carratelli units) than the control subjects (324.4 ± 34.0 Carratelli units; P <0.01). Probing depth, clinical attachment level, and bleeding on probing in patients with chronic periodontitis showed a significant improvement 2 months after non‐surgical periodontal treatment, and this was accompanied by a significant reduction in plasma ROM level (P <0.01).

Conclusions: In patients with chronic periodontitis, non‐surgical periodontal treatment was effective at improving clinical parameters and reducing plasma ROMs. The improvement in chronic periodontitis by non‐surgical periodontal treatment might offer clinical benefits by decreasing blood ROS.
Significance of the Epithelial Collar on the Subepithelial Connective Tissue Graft
Authors: Byun Ho‐Young , Oh Tae‐Ju , Abuhussein Heba M. , Yamashita Junro , Soehren Stephen E. , Wang Hom‐Lay
Published: June 2009

Background: Most clinicians adopt two versions of the subepithelial connective tissue graft (SCTG) procedure, SCTG with or without the epithelial collar on the graft combined with a coronally advanced flap (CAF). However, limited evidence is available to determine whether a retained epithelial collar on an SCTG is needed for a better outcome. The goal of this study was to compare the clinical outcomes of the two SCTG techniques (i.e., SCTG with or without an epithelial collar).

Methods: Twenty patients with Miller Class I or II gingival defects ≥2.0 mm were recruited for the study. The patients were randomly assigned to receive an SCTG with a retained epithelial collar + CAF (SCTGE; n = 10) or an SCTG without an epithelial collar + CAF (SCTGN; n = 10). Clinical parameters, including recession depth, recession width (RW), width of keratinized gingiva (KW), clinical attachment level (CAL), probing depth (PD), gingival index (GI), and plaque index (PI), were assessed at baseline and 3 and 6 months after surgery.

Results: SCTGE and SCTGN groups exhibited significant root coverage at 3 and 6 months compared to baseline (P <0.05). The SCTGE group had mean root coverage of 97.50% ± 7.90% at 6 months compared to 89.10% ± 25.93% in the SCTGN group, with no significant difference between the groups. At 6 months, complete root coverage was seen in nine of 10 and seven of 10 subjects from SCTGE and SCTGN groups, respectively. Mean KW at 3 months for the SCTGE group was 4.10 ± 1.10 mm, whereas in the SCTGN group it was 2.75 ± 0.68 mm. Mean RW was 0 mm and 1.20 ± 1.60 mm for SCTGE and SCTGN groups, respectively. KW and RW were statistically significantly different between the two groups at 3 months; however, this significance was not seen at 6 months. Other clinical parameters (CAL, PD, thickness of the recipient gingival tissue, PI, GI, and the wound healing index) showed no significant differences between the groups at any time point.

Conclusions: Both SCTG techniques (with or without the epithelial collar) provided predictable and successful root coverage (≥89%). This study suggests that a retained epithelial collar on the SCTG may not provide a significant benefit with regard to clinical parameters.
Fractional Flow Theory for Suspension Flow in Petroleum Reservoirs
Authors: Bedrikovetsky P. G. , Monteiro P. S. , Neto A. M. M. , Riente A. F.
Published: June 2009

Transport of particle suspensions in oil reservoirs occurs during sea or produced water injection with particle capture and consequent injectivity decline, produced water disposal in aquifers and subterranean water contamination, drilling fluid invasion causing formation damage, fines migration during production of heavy oils in low consolidated reservoirs resulting in productivity decline and during sand production control by gravel packs and sand screens.

Previous studies derive micro and macro scale equations for deep bed filtration in rocks. A finite size particle cannot enter smaller pore; it also cannot approach the wall of the larger pore closer that its radius. Therefore, mono dispersed suspension and clean water move in separate parts of porous space, and have different viscosities and densities. The suspension "saturation" is so-called accessibility factor. Relative permeabilities for each "phase" in modified Darcy's law depend on saturation and on deposited particle concentration. It closes system of equations for mono dispersed suspension transport in porous media. Finally, so-called flux reduction factor turned to be the fractional flow function. The closed macro scale system has fractional flow type. The developed model significantly differs from the classical filtration model.

In the current work, the laboratory data on injectivity impairment with suspension coreflood were treated. The model exhibits good agreement with experimental data.
The Interpretation and Application of Whole Core Analysis Data on Carbonate Reservoirs
Authors: Jenkins R.E. , Aufricht W.R.
Published: June 2009

In recent years, and particularly in the Rocky Mountain and West Texas areas, many commercially productive oil and gas reservoirs have been developed in low-permeability, often non-homogeneous, fractured and vuggy formations. In order to evaluate this non-homogeneous rock, whole core analysis techniques have been developed. The use of the whole core for analysis minimizes sampling errors and allows the inclusion of fractures and solution cavities in the test specimens.

Equipment and procedures used in whole core analysis methods are briefly discussed. Comparisons with conventional analysis methods are made to illustrate the type of formation where whole core analysis is desirable.

The major portion of this paper is devoted to examples of whole core analyses of reservoirs in the Rocky Mountain area and their interpretations. The interpretation of the data and its application are presented in terms of fluid contacts, probable production, and the estimation of oil-in-place and recoverable oil.

Introduction

During the last ten to fifteen years a large percentage of the oil and gas reservoirs discovered in the Rocky Mountain and West Texas areas have been in carbonate rocks. These carbonate formations are often characterized by erratic porosity and permeability development, and non-uniform lithology. In many cases, the porosity and permeability are due almost entirely to vugs and fractures.

The advent of diamond coring was of great benefit in the evaluation of carbonate reservoirs since it permitted faster penetration and much better recovery of dense, fractured formation. Another tool for the evaluation of these reservoirs which was developed to work hand-in-glove with the improved core recovery is whole core analysis.
Learning correction grammars
Authors: Carlucci Lorenzo , Case John , Jain Sanjay
Published: June 2009

We investigate a new paradigm in the context of learning in the limit, namely, learningcorrection grammarsfor classes ofcomputably enumerable (c.e.)languages. Knowing a language may feature a representation of it in terms oftwogrammars. The second grammar is used to make corrections to the first grammar. Such a pair of grammars can be seen as a single description of (or grammar for) the language. We call such grammarscorrection grammars. Correction grammars capture the observable fact that peopledocorrect their linguistic utterances during their usual linguistic activities.

We show that learning correction grammars for classes of c.e. languages in theTxtEx-mode(i.e., converging to a single correct correction grammar in the limit) is sometimes more powerful than learning ordinary grammars even in theTxtBc-model (where the learner is allowed to converge to infinitely many syntactically distinct but correct conjectures in the limit). For eachn≥ 0. there is a similar learning advantage, again in learning correction grammars for classes of c.e. languages, but where we compare learning correction grammars that maken+ 1 corrections to those that makencorrections.

The concept of a correction grammar can be extended into the constructive transfinite, using the idea of counting-down from notations for transfinite constructive ordinals. This transfinite extension can also be conceptualized as being about learning Ershov-descriptions for c.e. languages. Forua notation in Kleene's general system (O, <o) of ordinal notations for constructive ordinals, we introduce the concept of anu-correction grammar, whereuis used to bound the number of corrections that the grammar is allowed to make. We prove a general hierarchy result: ifuandvare notations for constructive ordinals such thatu<ov. then there are classes of c.e. languages that can beTxtEx-learned by conjecturingv-correction grammars but not by conjecturingu-correction grammars.

Surprisingly, we show that—above “ω-many” corrections—it is not possible to strengthen the hierarchy:TxtEx-learningu-correction grammars of classes of c.e. languages, whereuis a notation inOforanyordinal, can be simulated byTxtBc-learningw-correction grammars, wherewis any notation for the smallest infinite ordinalω.
The Dialectics of Multicultural Identity: Learning from Canada
Authors: Winter Elke
Published: June 2009

This paper theorizes the multiculturalization of national identity. Concentrating on the Canadian case, it examines newspaper discourses from the Globe and Mail and the Toronto Star during the 1990's. The analysis reveals that both Canada/USA comparisons and English Canada/Quebec comparisons play crucial roles for the construction of multicultural Canadian identity. The results from the empirical analysis are then used to nuance existing theories of multicultural nationalism.
Obesity Blunts Microvascular Recruitment in Human Forearm Muscle After a Mixed Meal
Authors: Keske Michelle A. , Clerk Lucy H. , Price Wendie J. , Jahn Linda A. , Barrett Eugene J.
Published: June 2009

OBJECTIVE

Ingestion of a mixed meal recruits flow to muscle capillaries and increases total forearm blood flow in healthy young lean people. We examined whether these vascular responses are blunted by obesity.

RESEARCH DESIGN AND METHODS

We fed eight middle-aged lean and eight obese overnight-fasted volunteers a liquid mixed meal (480 kcal). Plasma glucose and insulin were measured every 30 min, and brachial artery flow and muscle microvascular recruitment (contrast ultrasound) were assessed every 60 min over 2 h after the meal.

RESULTS

By 30 min, plasma glucose rose in both the lean (5.1 ± 0.1 vs. 6.7 ± 0.4 mmol/l, P < 0.05) and the obese groups (5.4 ± 0.2 vs. 6.7 ± 0.4 mmol/l, P < 0.05). Plasma insulin rose (28 ± 4 vs. 241 ± 30 pmol/l, P < 0.05) by 30 min in the lean group and remained elevated for 2 h. The obese group had higher fasting plasma insulin levels (65 ± 8 pmol/l, P < 0.001) and a greater postmeal area under the insulin-time curve (P < 0.05). Brachial artery flow was increased at 120 min after the meal in the lean group (38 ± 6 vs. 83 ± 16 ml/min, P < 0.05) but not in the obese group. Muscle microvascular blood volume rose by 120 min in the lean group (14.4 ± 2.2 vs. 24.4 ± 4.2 units, P < 0.05) but not in the obese group.

CONCLUSIONS

A mixed meal recruits muscle microvasculature in lean subjects, and this effect is blunted by obesity. This impaired vascular recruitment lessens the endothelial surface available and may thereby impair postprandial glucose disposal.
Effects of Acute Insulin-Induced Hypoglycemia on Spatial Abilities in Adults With Type 1 Diabetes
Authors: Wright Rohana J. , Frier Brian M. , Deary Ian J.
Published: June 2009

OBJECTIVE

To examine the effects of acute insulin-induced hypoglycemia on spatial cognitive abilities in adult humans with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Sixteen adults with type 1 diabetes underwent two counterbalanced experimental sessions: euglycemia (blood glucose 4.5 mmol/l [81 mg/dl]) and hypoglycemia (2.5 mmol/l [45 mg/dl]). Arterialized blood glucose levels were maintained using a hyperinsulinemic glucose clamp technique. During each session, subjects underwent detailed assessment of spatial abilities from the Kit of Factor-Referenced Cognitive Tests and two tests of general cognitive function.

RESULTS

Spatial ability performance deteriorated significantly during hypoglycemia. Results for the Hidden Patterns, Card Rotations, Paper Folding, and Maze Tracing tests were all impaired significantly (P ≤ 0.001) during hypoglycemia, as were results for the Cube Comparisons Test (P = 0.03). The Map Memory Test was not significantly affected by hypoglycemia.

CONCLUSIONS

Hypoglycemia is a common side effect of insulin therapy in individuals with type 1 diabetes, and spatial abilities are of critical importance in day-to-day functioning. The deterioration in spatial abilities observed during modest experimental hypoglycemia provides novel information on the cerebral hazards of hypoglycemia that has potential relevance to everyday activities.
Five-Year Change in Visceral Adipose Tissue Quantity in a Minority Cohort: The Insulin Resistance Atherosclerosis Study (IRAS) Family Study
Authors: Hairston Kristen G. , Scherzinger Ann , Foy Capri , Hanley Anthony J. , McCorkle Orita , Haffner Steven , Norris Jill M. , Bryer-Ash Michael , Wagenknecht Lynne E.
Published: June 2009

OBJECTIVE

To describe the 5-year change in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas.

RESEARCH DESIGN AND METHODS

Absolute change in VAT and SAT measured by abdominal computed tomography scans has been obtained at a 5-year interval from African Americans (n = 389) and Hispanic Americans (n = 844), aged 20–69 years, in 10-year age-groups.

RESULTS

Mean 5-year increases in VAT areas in women were 18, 7, 4, 0.4, and −3 cm2 for African Americans and 13, 7, 3, 1, and −15 cm2 for Hispanics, across the 5 age decades (trend not significant). Mean 5-year increases in SAT areas in women were 88, 46, 19, 17, and 14 cm2 for African Americans and 53, 20, 17, 12, and 1 cm2 for Hispanics, across the 5 age decades (P < 0.05 for both). Similar trends have been observed in men.

CONCLUSIONS

Accumulation of abdominal fat is greatest in young adulthood. These data may be useful in identifying subgroups at risk of type 2 diabetes.
Prevalence and Risk Factors for Urinary Incontinence in Overweight and Obese Diabetic Women
Authors: Phelan Suzanne , Kanaya Alka M. , Subak Leslee L. , Hogan Patricia E. , Espeland Mark A. , Wing Rena R. , Burgio Kathryn L. , DiLillo Vicki , Gorin Amy A. , West Delia S. , Brown Jeanette S.
Published: June 2009

OBJECTIVE

To determine the prevalence and risk factors for urinary incontinence among different racial/ethnic groups of overweight and obese women with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Cross-sectional analysis of baseline data from the Action for Health in Diabetes (Look AHEAD) study, a randomized clinical trial with 2,994 overweight/obese women with type 2 diabetes.

RESULTS

Weekly incontinence (27%) was reported more often than other diabetes-associated complications, including retinopathy (7.5%), microalbuminuria (2.2%), and neuropathy (1.5%). The prevalence of weekly incontinence was highest among non-Hispanic whites (32%) and lowest among African Americans (18%), and Asians (12%) (P < 0.001). Asian and African American women had lower odds of weekly incontinence compared with non-Hispanic whites (75 and 55% lower, respectively; P < 0.001). Women with a BMI of ≥35 kg/m2 had a higher odds of overall and stress incontinence (55–85% higher; P < 0.03) compared with that for nonobese women. Risk factors for overall incontinence, as well as for stress and urgency incontinence, included prior hysterectomy (40–80% increased risk; P < 0.01) and urinary tract infection in the prior year (55–90% increased risk; P < 0.001).

CONCLUSIONS

Among overweight and obese women with type 2 diabetes, urinary incontinence is highly prevalent and far exceeds the prevalence of other diabetes complications. Racial/ethnic differences in incontinence prevalence are similar to those in women without diabetes, affecting non-Hispanic whites more than Asians and African Americans. Increasing obesity (BMI ≥35 kg/m2) was the strongest modifiable risk factor for overall incontinence and stress incontinence in this diverse cohort.
Circulating Fibroblast Growth Factor-21 Is Elevated in Impaired Glucose Tolerance and Type 2 Diabetes and Correlates With Muscle and Hepatic Insulin Resistance
Authors: Chavez Alberto O. , Molina-Carrion Marjorie , Abdul-Ghani Muhammad A. , Folli Franco , DeFronzo Ralph A. , Tripathy Devjit
Published: June 2009

OBJECTIVE

Fibroblast growth factor (FGF)-21 is highly expressed in the liver and regulates hepatic glucose production and lipid metabolism in rodents. However, its role in the pathogenesis of type 2 diabetes in humans remains to be defined. The aim of this study was to quantitate circulating plasma FGF-21 levels and examine their relationship with insulin sensitivity in subjects with varying degrees of obesity and glucose tolerance.

RESEARCH DESIGN AND METHODS

Forty-one subjects (8 lean with normal glucose tolerance [NGT], 9 obese with NGT, 12 with impaired fasting glucose [IFG]/impaired glucose tolerance [IGT], and 12 type 2 diabetic subjects) received an oral glucose tolerance test (OGTT) and a hyperinsulinemic-euglycemic clamp (80 mU/m2 per min) combined with 3-[3H] glucose infusion.

RESULTS

Subjects with type 2 diabetes, subjects with IGT, and obese subjects with NGT were insulin resistant compared with lean subjects with NGT. Plasma FGF-21 levels progressively increased from 3.9 ± 0.3 ng/ml in lean subjects with NGT to 4.9 ± 0.2 in obese subjects with NGT to 5.2 ± 0.2 in subjects with IGT and to 5.3 ± 0.2 in type 2 diabetic subjects. FGF-21 levels correlated inversely with whole-body (primarily reflects muscle) insulin sensitivity (r = −0.421, P = 0.007) and directly with the hepatic insulin resistance index (r = 0.344, P = 0.034). FGF-21 levels also correlated with measures of glycemia (fasting plasma glucose [r = 0.312, P = 0.05], 2-h plasma glucose [r = 0.414, P = 0.01], and A1C [r = 0.325, P = 0.04]).

CONCLUSIONS

Plasma FGF-21 levels are increased in insulin-resistant states and correlate with hepatic and whole-body (muscle) insulin resistance. FGF-21 may play a role in pathogenesis of hepatic and whole-body insulin resistance in type 2 diabetes.
A critical appraisal of drainage in syringomyelia
Authors: Sgouros Spiros , Williams Bernard
Published: June 2009

✓ The use of drains in the treatment of syringomyelia has a simple and immediate appeal and has been practiced widely since the report of Abbe and Coley over 100 years ago. Good short-term results have been claimed in the past, but long-term outcome is largely unknown. An experience in Birmingham, England is reviewed in which 73 patients who had had some form of syrinx drainage procedure performed were subsequently followed up. In these cases, a total of 56 syringopleural and 14 syringosubarachnoid shunts had been inserted. Ten years after the operations, only 53.5% and 50% of the patients, respectively, continued to remain clinically stable. A 15.7% complication rate was recorded, including fatal hemorrhage, infection, and displacement of the drain from the pleural and syrinx cavities. At second operation or necropsy, at least 5% of shunts were discovered to be blocked. The effect of other drainage procedures that do not use artificial tubing, such as syringotomy and terminal ventriculostomy, was analyzed but found not to offer any substantial benefit. These results indicate that drainage procedures are not an effective solution to remedying the progressive, destructive nature of syringomyelia. It is suggested that, rather than attempting to drain the syrinx cavity, disabling the filling mechanism of the syrinx is more appropriate. Most forms of syringomyelia have a blockage at the level of the foramen magnum or in the subarachnoid space of the spine. Surgical measures that aim to reconstruct the continuity of the subarachnoid space at the site of the block are strongly recommended. Lowering the overall pressure of the cerebrospinal fluid is advocated when reestablishment of the pathways proves impossible.

Syrinx drainage as an adjuvant to more physiological surgery may have a place in the treatment of syringomyelia. If two procedures are done at the same time, however, it is difficult to ascribe with certainty a success or failure, and it is suggested that the drainage procedure be reserved for a later attempt if the elective first operation fails.
Spinal cord stimulation in the treatment of paraplegic pain
Authors: Cioni Beatrice , Meglio Mario , Pentimalli Luigi , Visocchi Massimiliano
Published: June 2009

✓ Twenty-five patients suffering from intractable pain due to a chronic spinal cord lesion underwent a percutaneous test of spinal cord stimulation. At the end of the test period, 40.9% of the patients reported a mean of 65% pain relief and these patients were selected for ongoing stimulation. At a mean follow-up time of 37.2 months the success rate, based on the number of patients with more than 50% pain relief, had fallen to 18.2%. Pain relief rates were analyzed in relation to quality of pain, neurological status, level and extent of the lesion, and electrode level to identify prognostic factors that could improve the clinical usefulness of spinal cord stimulation. Patients experiencing painful spasms or a constrictive type of pain and with incomplete thoracic lesions were found to be the best candidates for spinal cord stimulation.
Coagulopathy with the use of hetastarch in the treatment of vasospasm
Authors: Trumble Eric R. , Muizelaar J. Paul , Myseros John S. , Choi Sung C. , Warren Brian B.
Published: June 2009

✓ The use of colloid agents to achieve hypervolemia in the prevention and treatment of postsubarachnoid hemorrhage (post-SAH) vasospasm is included in the standard of care at many institutions. Risk profiles are necessary to ensure appropriate use of these agents. In a series of 85 patients with recent aneurysmal SAH, 26 developed clinical symptoms of vasospasm. Fourteen of the 26 were treated with hetastarch for volume expansion while the other 12 received plasma protein fraction (PPF). Clinically significant bleeding pathologies were noted in six patients who received hetastarch as a continuous intravenous infusion. Hetastarch increased partial thromboplastin time from a mean of 23.9 seconds to a mean of 33.1 seconds (p < 0.001) in all patients who received infusions of this agent, while no effect was noted in the 12 patients who received PPF infusions. No other coagulation parameters were altered. This study shows an increase in coagulopathy with the use of hetastarch as compared with the use of PPF for the treatment of postaneurysmal vasospasm.
Endothelin concentrations in patients with aneurysmal subarachnoid hemorrhage
Authors: Seifert Volker , Löffler Bernd-Michael , Zimmermann Michael , Roux Sébastiên , Stolke Dietmar
Published: June 2009

✓ Plasma and cerebrospinal fluid (CSF) concentrations of endothelin (ET)-1, ET-3, and big ET-1 in patients with aneurysmal rupture were measured serially for 2 weeks after the onset of aneurysmal subarachnoid hemorrhage (SAH) and compared with levels of ETs in patients without SAH and the plasma concentrations of ETs in normal volunteers. Big ET-1 was the predominant peptide present in the CSF of SAH patients. The CSF concentrations of big ET-1, ET-1, and ET-3 were significantly higher in older patients than in younger patients. In SAH patients with cerebral vasospasm (CVS) documented by transcranial Doppler sonography and clinical signs, postoperative concentrations of ETs in the CSF remained at or were increased above levels measured before surgery. In SAH patients without CVS, the concentrations of ETs in the CSF decreased with time, whereas the time course of CVS coincided with the increase in concentrations of big ET-1 and ET-1. The temporal dependence of concentrations of big ET-1 and ET-1 in SAH patients with and without CVS were significantly different. The volume of hematoma in the basal cisterns as detected by computerized tomography was predictive of the concentrations of ETs in the CSF. Plasma concentrations of ETs were not correlated wtih CVS. The possible role of ETs in the pathogenesis of CVS associated with SAH and the controversial data reported to date are discussed.
Adenovirally mediated gene transfer into experimental solid brain tumors and leptomeningeal cancer cells
Authors: Viola John J. , Ram Zvi , Walbridge Stuart , Oshiro Eric M. , Trapnell Bruce , Tao-Cheng Jung-Hwa , Oldfield Edward H.
Published: June 2009

✓ Among the appealing features of adenoviruses as vectors for transfer of genes into the central nervous system (CNS) are that they are not neurotoxic, they can accommodate the insertion of several large genes, they are not associated with the hazards of insertional mutagenesis, and they can be concentrated to a high-titer preparation. The authors evaluated the feasibility of using adenovirally mediated gene transfer into cultured human glioma cells and in rat models of solid brain tumors and meningeal cancer. Replication-deficient adenoviral vector particles carrying a nuclear-localizing lacZ gene were injected into established 9L cerebral gliomas in Fischer rats. In addition, the adenoviral vector was injected into the subarachnoid space, either simultaneously with intrathecal tumor inoculation or after establishing leptomeningeal cancer. The brains and spinal cords were removed at various intervals for histochemical evaluation for β-galactosidase activity using X-Gal staining. Additional rats received a stereotactic intracerebral injection of the vector into normal brain. No clinical abnormalities were observed in the injected rats. Injection of the adenoviral vector into normal brain resulted in diffuse transduction of astrocytes, microglia, neurons, and endothelial cells at the injection site. Injection of a high-concentration vector preparation into cerebral gliomas resulted in effective tumor transduction. Intrathecal injection of the vector in rats with meningeal cancer resulted in transduction of the infiltrating tumor in the subarachnoid space when injections were given simultaneously with, or 7 days after, tumor inoculation. Transduction rates of both solid and leptomeningeal tumors correlated with the number of injected particles. These results suggest that adenoviral vectors can efficiently transduce solid brain tumors and that the vectors survive in the cerebrospinal fluid for a sufficient period of time to allow leptomeningeal tumor transduction. Adenoviral vector should be evaluated for its potential use in therapeutic gene transfer approaches in malignancies of the CNS.
Primary peripheral—postthymic T-cell lymphoma in the central nervous system: immunological and molecular approaches to diagnosis
Authors: Nitta Taizo , Uda Ken , Ebato Michimasa , Ikezaki Kiyonobu , Fukui Masashi , Sato Kiyoshi
Published: June 2009

✓ Primary intracranial T-cell lymphoma is a very rare clinical entity, and only limited biological studies of this disease have been undertaken. A tumor specimen from a patient with a primary leptomeningeal and perivascular presentation of a T-cell lymphoma was analyzed using cellular and molecular techniques. Frozen sections of the sample were examined by immunohistochemical techniques using monoclonal antibodies to phenotypic marker antigens expressed on human lymphoid cells. Intercellular adhesion molecules expressed on the tumor were studied, as was expression of messenger ribonucleic acid (mRNA) transcripts of the T-cell receptor variable α and β chain genes. The immunophenotypical analysis of lymphoma revealed that the tumor expressed CD2, CD3, CD4, CD5, CD25 and HLA-DR. In addition, all of the adhesion molecules studied (ICAM-1, LFA-3, VLA-1, CD11a, CD11b, and CD11c) were detected on the cell surface. Polymerase chain reaction amplification of mRNA from the tumor demonstrated 10 Vα and three Vβ T-cell receptor subfamilies, indicating that this tumor was a low-grade well-differentiated helper type of peripheral T-cell lymphoma of the central nervous system. In addition, the tumor was derived from multiple T-cell lineages.
Focal brain injury and upregulation of a developmentally regulated extracellular matrix protein
Authors: Brodkey Jason A. , Laywell Eric D. , O'Brien Thomas F. , Faissner Andreas , Stefansson Kari , Dörries H. Ulrich , Schachner Melitta , Steindler Dennis A.
Published: June 2009

✓ Tenascin is an extracellular matrix glycoprotein expressed during both normal development and neoplastic growth in both neural and nonneural tissues. During development of the central nervous system (CNS), tenascin is synthesized by glial cells, in particular by immature astrocytes, and is concentrated in transient boundaries around emerging groups of functionally distinct neurons. In the mature CNS, only low levels of the glycoprotein can be detected. The present study demonstrates that following trauma to the adult human cerebral cortex, discrete populations of reactive astrocytes upregulate their expression of tenascin and dramatically increase their transcription of the tenascin gene. The enhanced expression of tenascin may be involved in CNS wound healing, and may also affect neurite growth within and around a brain lesion.
Delayed occurrence of cerebellar pleomorphic xanthoastrocytoma after supratentorial pleomorphic xanthoastrocytoma removal
Authors: Glasser Ryan S. , Rojiani Amyn M. , Mickle J. Parker , Eskin Thomas A.
Published: June 2009

✓ The authors report the case of a 36-year-old woman who underwent gross total resection of a right cerebellar pleomorphic xanthoastrocytoma with atypical features. She had undergone surgery 16 years previously for what was thought to be a right frontal glioblastoma multiforme. In retrospect, based on the histopathology and the clinical course, both lesions were considered to represent atypical variants of pleomorphic xanthoastrocytoma. This report examines the histological and clinical characteristics of this posterior fossa lesion, which exhibited histologically malignant features but has run a relatively indolent course.
Spinal cord compression due to Masson's vegetant intravascular hemangioendothelioma
Authors: Porter David G. , Martin Andrew J. , Mallucci Conor L. , Makunura Catherine N. , Sabin H. Ian
Published: June 2009

✓ The authors present the case of spinal cord compression in a 16-year-old boy due to the rare vascular lesion, Masson's vegetant hemangioendothelioma.
Herniation of the spinal cord
Authors: Kumar Rakesh , Taha Jamal , Greiner Alson Lee
Published: June 2009

✓ Herniation of the spinal cord, or displacement of the cord outside the dura, is so rare that only 13 cases have been reported in the literature. The authors report a new case of spontaneous herniation of the spinal cord in a 38-year-old man who presented with lower left limb paresis and Brown-Séquard syndrome, with a T-8 sensory level. Displacement of the spinal cord was noted on computerized tomography following myelography and on magnetic resonance imaging. The herniated cord was confirmed at operation and reduced intradurally. Postoperatively, the patient showed complete neurological recovery.

Based on a review of the literature, herniation of the spinal cord may be classified as spontaneous, iatrogenic, or traumatic. At cervical levels, the spinal cord has herniated into an iatrogenic pseudomeningocele located dorsally. At thoracic levels, spinal cord herniations were reported to be in a preexisting extradural arachnoid cyst located ventrally. The authors propose a pathogenesis for spinal cord herniation based on abnormal positioning of the spinal cord in the dural sleeve and the known anteroposterior movements of the cord that occur with cardiac and respiratory pulsations. The presence of a dural defect situated on the concavity of the spinal curvature is a prerequisite for this rare condition. As adhesions develop between the cord and the edges of the dural defect, cerebrospinal fluid pulsations push the cord into a preexisting cyst. The authors suggest modifying the classification by Nabors, et al., of spinal meningeal cysts to include this mechanism of spinal cord herniation. This diagnosis should also be considered in the differential diagnosis of myelopathy in the absence of a mass lesion.
Treatment of vertebral artery dissecting aneurysm by aneurysm trapping and posterior inferior cerebellar artery reimplantation
Authors: Durward Quentin J.
Published: June 2009

✓ The author presents the case of a patient with a ruptured vertebral artery dissecting aneurysm in which the posterior inferior cerebellar artery (PICA) arose from the wall of the aneurysm. The aneurysm was treated by trapping and the PICA was anastomosed to the vertebral artery proximal to the dissection. This technique allows intraoperative obliteration of the aneurysm while maintaining normal blood flow to the PICA.
Microvascular decompression for hemifacial spasm
Authors: Barker Fred G. , Jannetta Peter J. , Bissonette David J. , Shields Philip T. , Larkins Mark V. , Jho Hae Dong
Published: June 2009

✓ The authors report the results of 782 microvascular decompression procedures for hemifacial spasm in 703 patients (705 sides), with follow-up study from 1 to 20 years (mean 8 years). Of 648 patients who had not undergone prior intracranial procedures for hemifacial spasm, 65% were women; their mean age was 52 years, and the mean preoperative duration of symptoms was 7 years. The onset of symptoms was typical in 92% and atypical in 8%. An additional 57 patients who had undergone prior microvascular decompression elsewhere were analyzed as a separate group. Patients were followed prospectively with annual questionnaires.

Kaplan-Meier methods showed that among patients without prior microvascular decompression elsewhere, 84% had excellent results and 7% had partial success 10 years postoperatively. Subgroup analyses (Cox proportional hazards model) showed that men had better results than women, and patients with typical onset of symptoms had better results than those with atypical onset. Nearly all failures occurred within 24 months of operation; 9% of patients underwent reoperation for recurrent symptoms. Second microvascular decompression procedures were less successful, whether the first procedure was performed at Presbyterian-University Hospital or elsewhere, unless the procedure was performed within 30 days after the first microvascular decompression. Patient age, side and preoperative duration of symptoms, history of Bell's palsy, preoperative presence of facial weakness or synkinesis, and implant material used had no influence on postoperative results.

Complications after the first microvascular decompression for hemifacial spasm included ipsilateral deaf ear in 2.6% and ipsilateral permanent, severe facial weakness in 0.9% of patients. Complications were more frequent in reoperated patients. In all, one operative death (0.1%) and two brainstem infarctions (0.3%) occurred. Microvascular decompression is a safe and definitive treatment for hemifacial spasm with proven long-term efficacy.
Influence of the type of initial precipitating injury and at what age it occurs on course and outcome in patients with temporal lobe seizures
Authors: Mathern Gary W. , Pretorius James K. , Babb Thomas L.
Published: June 2009

✓ The type of initial precipitating injury and the age at which it occurred in 20 patients with nonlesional temporal lobe epilepsy (TLE) were related to clinical features, presurgical neuroimaging, quantified hippocampal pathologies, and seizure outcomes. Clinical data, neuroimaging records, and seizure outcomes were abstracted from medical records and confirmed with patient and family contacts. Hippocampal neuron losses and mossy fiber reactive synaptogenesis were quantified independently. Results showed that the type of initial precipitating injury and the patient's age at which it occurred were related to the clinicopathological features of TLE. An initial precipitating injury occurred in 18 patients (90%), all of whom had mesial temporal sclerosis (MTS). Patients with a prolonged initial seizure or a nonseizure initial precipitating injury before age 5 years were significantly more likely to have unilateral hippocampal atrophy (p < 0.05) shown on magnetic resonance (MR) imaging, and had significantly greater inner molecular layer mossy fiber puncta densities (p < 0.001) than patients with nonprolonged childhood initial precipitating injuries and/or seizures after age 5 years. Furthermore, nonseizure injuries in patients before age 5 years had significantly longer latent periods (p < 0.05), and the patients did not respond to surgical treatment as well as other MTS patients. Those with an initial precipitating injury after age 5 years had MTS but showed significantly less inner molecular layer mossy fiber sprouting (p < 0.05) than patients whose injuries appeared before age 5 years. Patients without an initial precipitating injury (idiopathic TLE) had significantly fewer neuron losses (p < 0.05) and inner molecular layer mossy fiber puncta densities (p < 0.05) and had worse outcomes following en bloc temporal lobectomy compared to patients with MTS who had experienced initial precipitating injuries. Patients with unilateral hippocampal abnormalities on MR imaging did not show significant differences in neuron losses or aberrant mossy fiber puncta densities compared to patients without asymmetry. These results support the hypothesis that the type of initial precipitating injury and the age at which the injury occurred initiates and influences the pathophysiological process that eventually develops into MTS. These data support the notion that the pathophysiology of hippocampal damage and mossy fiber sprouting after an initial precipitating injury may be a progressive process.
Unilateral hippocampal mossy fiber sprouting and bilateral asymmetric neuron loss with episodic postictal psychosis
Authors: Mathern Gary W. , Pretorius James K. , Babb Thomas L. , Quinn Bruce
Published: June 2009

✓ Rarely are both sides of the hippocampus available for pathological study in a patient with intractable temporal lobe epilepsy (TLE). The authors report a patient with TLE investigated with bilateral depth electrodes who had an episode of postictal psychosis. The patient died 4 weeks after temporal lobectomy of unknown reasons, despite complete postmortem examination and clinical evidence of postsurgery seizure control. Pathological examination of surgical and autopsy hippocampal specimens found bilateral asymmetric neuron losses. However, only the resected epileptogenic hippocampus showed the profile of neuron loss typical of mesial temporal sclerosis (MTS) and abnormal mossy fiber synaptic reorganization. Quantitative depth electroencephalographic (EEG) analysis of the postictal psychotic event showed that it was not associated with a cluster of seizures, increased postictal depth EEG spike activity, or insufficient antiepileptic medication. These results support the hypothesis that ipsilateral hippocampal epileptogenesis is associated with MTS and mossy fiber sprouting. The results also suggest that the etiology of postictal psychosis in this patient was initiated by an ictal event and the behavior apparently depended on seizure propagation outside the hippocampus. The relevance of these two findings to the literature is discussed.
Insulin reduction of cerebral infarction due to transient focal ischemia
Authors: Hamilton Mark G. , Tranmer Bruce I. , Auer Roland N.
Published: June 2009

✓ Insulin has recently been shown to ameliorate damage in models of global brain ischemia. To determine whether insulin is also neuroprotective in focal ischemia, 20 rats were given 2 to 3 IU/kg insulin and 10 did not receive treatment prior to normothermic transient middle cerebral artery occlusion for 2 hours at a blood pressure of 60 mm Hg. To further elucidate whether infarction volume is influenced by variations in blood glucose levels within the physiological range, blood glucose was raised in 10 of the insulin-treated animals to levels comparable with the untreated controls. At 1-week survival, damage was assessed using quantitative neuropathological examination of 25 coronal planes. It was found that preischemic insulin lowered the mean intraischemic blood glucose level from 8.4 ± 0.2 mM (µ ± standard error of the mean) in the control group to 3.4 ± 0.2 mM and reduced total damage (atrophy plus cortical and striatal necrosis), expressed as the percentage of the normal hemisphere, from a control of 28.5% ± 2.9% to 14.5% ± 1.6% (p < 0.005). Coadministration of glucose and insulin resulted in a mean intraischemic blood glucose level of 10.1 ± 0.5 mM, with 27.0% ± 2.4% total damage (p = 0.96, compared with control). Total ischemic damage showed an independent correlation with blood glucose levels (r = 0.67, p = 0.0018).

The findings indicate that insulin benefits transient focal ischemia and that reducing the blood glucose from 8 to 9 mM to the low-normal range of 3 to 4 mM with insulin dramatically reduces subsequent infarction. The data suggest that the neuroprotective mechanism of insulin action in focal middle cerebral artery occlusion is mediated predominantly via alterations in blood glucose levels. In comparison to global ischemia, focal ischemia appears to show only a minor direct central nervous system effect of insulin. In clinical situations in which transient focal ischemia to the hemisphere can be anticipated, insulin-induced hypoglycemia of a mild degree may be beneficial.
Limited protective effects of etomidate during brainstem ischemia in dogs
Authors: Guo Jing , White Jonathan A. , Batjer H. Hunt
Published: June 2009

✓ To evaluate etomidate as a neuroprotective agent in the brain stem, 33 dogs were divided into seven groups and were exposed to isolated, reversible brainstem ischemia in the presence or absence of etomidate using a newly developed canine model of brainstem ischemia. Brainstem auditory evoked potentials (BAEP) and regional cerebral blood flow were measured during ischemia and for 5 hours after reperfusion. This model provides a potential physiological environment in which to test the efficacy of putative brainstem ischemic protective strategies.

During ischemia, BAEP were abolished in all animals. Without etomidate 10 minutes of ischemia was of short enough duration to allow complete recovery of BAEP. Ischemia of 20 or 30 minutes' duration resulted in minimal recovery. The dose of etomidate administered did not suppress BAEP or brainstem cardiovascular response to ischemia. In animals receiving etomidate and rendered ischemic for 20 minutes, a significant but only temporary recovery in BAEP was seen. Etomidate failed to have a significant effect in animals rendered ischemic for 30 minutes.

The minimal effect of etomidate on the current measures of brainstem function is in contrast to etomidate's known suppressive effect on cortical electroencephalogram and predicts that etomidate does little to alter brainstem metabolism. Etomidate's failure to provide for permanent recovery of BAEP suggests that the drug does not give sufficient protection from ischemia to the brainstem neurons in the auditory pathway. If these auditory neurons reflect brainstem function as a whole, etomidate may not be the protective agent of choice during temporary arterial occlusion of posterior circulation.
An additional therapeutic effect of adequate hyperventilation in severe acute brain trauma: normalization of cerebral glucose uptake
Authors: Cruz Julio
Published: June 2009

✓ In a total of 309 frequent serial studies, arteriojugular differences in glucose and oxygen levels were concurrently evaluated in 33 adult patients who were experiencing the most acute phase of severe brain trauma.

Hyperventilation therapy was optimized to maintain both normalized intracranial pressure and cerebral extraction of oxygen. Under these circumstances, global cerebral glucose extraction was found to be closest to normal during profound optimized hyperventilation, with PaCO2 levels below 25 mm Hg. In contrast, during normocapnia global cerebral glucose extraction dropped below normal range, indicating impairment of cerebral glucose uptake.

Findings from this study show that in severe acute brain injury, optimized hyperventilation exerts an additional metabolic effect with respect to cerebral glucose uptake.
A clinicopathological study of collagen sponge as a dural graft in neurosurgery
Authors: Narotam Pradeep K. , van Dellen James R. , Bhoola Keshavlal D.
Published: June 2009

✓ There is frequently a need for dural grafts to cover defects resulting from retraction, shrinkage, or excision following neurosurgical procedures. Several materials have been evaluated both experimentally and clinically, and then discarded. Collagen, in its various forms, continues to be an area of intense interest. In this study the authors examined the suitability of collagen sponge to effect dural repair.

In a 5-year clinical study 102 collagen sponge implants were examined macroscopically and histologically. Graft encapsulation, neomembrane formation, delayed hemorrhage, and foreign body reactions were not found. The porous nature of the collagen sponge encouraged fibroblastic ingrowth and dural repair. Meningocerebral adhesions were present in 11 patients, all of whom had required significant cortical resection or had pia-arachnoid disruption during the initial surgery. Inflammatory cells were seen only in response to infection.

Postoperative cerebrospinal fluid leaks developed in only three of 67 patients who underwent an intradural posterior fossa procedure. In a prospective arm of the study involving 459 patients, the wound infection rate using collagen sponge was 6.1%, which compared favorably (p = 0.67) with the 5.7% rate in a similar group of 637 patients in whom collagen sponge had not been used.