bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative investigation on the impact of polymeric substances on membrane fouling during sub-critical and critical flux operation of a municipal membrane bioreactor
Authors: Lyko S. , Wintgens T. , Melin T.
Published: November 2008

Soluble organic macromolecules are ubiquitous in activated sludge supernatant. For the operation of membrane bioreactors (MBR) this group of substances is considered as the dominant factor causing severe membrane fouling due to the concentration polarisation phenomenon. The well established critical flux concept for the characterisation of membrane bioreactor's operation limits is based on filtration data only. As there is an cause-and-effect relation between the partial retention of organic compounds and the limited flux according the critical flux concept the aim of this study was to draw a comparison between different permeate fluxes on the retention of organic macromolecules. Thus, a municipal pilot-scale MBR with three capillary hollow fibre membrane modules was operated in sub critical, critical and supercritical flux mode, respectively and the retention of macromolecules was quantified by size exclusion chromatography. Three permeate extraction pumps allow a simultaneous operation with different operational conditions for each membrane module and proved the crucial impact of permeate flux on the fouling rate. The interchange of these conditions gave evidence of an optimised start-up procedure for MBRs characterised by higher permeate fluxes. An increased flux causes both a higher retention of soluble macromolecules and subsequent a higher fouling rate.
Sustainable nitrogen removal from wastewater with the hybrid membrane biofilm process (HMBP): bench-scale studies
Authors: Downing Leon S. , Nerenberg Robert
Published: November 2008

The hybrid membrane biofilm process (HMBP) is a novel approach to achieving total nitrogen removal from wastewater. It incorporates air-supplying, hollow-fiber membranes into a conventional activated sludge tank, where bulk aeration is suppressed. A nitrifying biofilm grows on the membranes and exports nitrite and nitrate to the anoxic bulk liquid, where suspended heterotrophic bacteria denitrify using influent BOD as an electron donor. Bench scale tests were used to assess the performance of the HMBP for a variety of nitrogen and BOD loading rates. For a nitrogen loading of 1.6 gN m−2, the nitrification flux remained at approximately 1.0 gN m−2 d−1 for BOD loadings ranging from 4 to 17 gBOD m−2 d−1 day−1. Full denitrification was achieved when sufficient BOD was available in the influent. Microsensor measurements indicated nitrite was the dominant form of oxidized nitrogen produced by the biofilm, showing that shortcut nitrogen removal was taking place. Fluorescence in-situ hybridization (FISH) tests on the biofilm revealed a unique stratification, with three distinct regions: AOB and NOB near the membrane, strictly AOB at intermediate depths, and AOB and heterotrophs at the outer edge of the biofilm.
Use of RNA-based genotypic approaches for quantification of viable but non-culturable Salmonella sp. in biosolids
Authors: Dunaev T. , Alanya S. , Duran M.
Published: November 2008

Recent research efforts demonstrated an increase in fecal coliform counts in anaerobically digested biosolids after dewatering. Variety of bacteria enters viable but nonculturable (VNC) state as a survival response when exposed to environmental stress. Increase in coliform concentration after digestion and dewatering processes have been attributed to cells going into a viable but non-culturable state implying that traditional coliform enumeration methods are not sufficient to determine number of viable cells. Therefore, this research has been undertaken to develop a method for rapid and accurate quantification of viable but non-culturable pathogens in biosolids via monitoring and quantifying stress-related genes in Salmonella sp. The proposed method has the potential to allow accurate detection of pathogens in biosolids even when the cells are non-culturable due to environmental stress. The research proposed identification of stress related genes in Salmonella when cells are exposed to heat for different durations by using available Salmonella microarrays. In the context of this study the identified stress genes can be quantified through reverse transcription, complementary DNA (cDNA) synthesis, and amplification of cDNA via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Then quantity of mRNA can be correlated to cell viability and cells ability to grow, i.e., their culturability. Development of a novel approach to understand the pathogen behaviour in biosolids is key to ensure low public health risks from biosolids. Nevertheless, the initial results suggest that intact RNA isolation from biosolids is still challenging task.
Grid size effects on a distributed water quantity-quality model in a hilly watershed
Authors: Shivakoti Binaya Raj , Fujii Shigeo , Boontanon Suwanna Kitpati , Ihara Hirotaka , Moriya Masashi , Tanaka Shuhei
Published: November 2008

Effects of different grid sizes (50 m, 100 m, 150 m, … , 500 m) were analyzed for both watershed attributes and estimation by a distributed model for flow rate and water quality. Model was evaluated in terms of estimation differences and on the values of some parameters at different grid sizes. Grid resizing showed significant changes in the physical attributes related with topography, but attributes such as land cover and geology were not much affected. Model showed increasing flow rates estimation with increasing grid size when the same parameter values were used. Such increasing pattern was observed for root mean square error, magnitude of peak runoff points, and time for the peak recession. Observed differences did not show such variation patterns in case of water quality estimation at different grid sizes. The observed differences in the estimated value by the model could have been derived mainly from less number of grids required to travel, increased proportion of channel grids and smaller outlet height at coarser grid sizes. These estimated differences could be adjusted by changing values of some of the model parameters for each grid size within a narrow range.
Roles of IP3R and RyR Ca2+ Channels in Endoplasmic Reticulum Stress and β-Cell Death
Authors: Luciani Dan S. , Gwiazda Kamila S. , Yang Ting-Lin B. , Kalynyak Tatyana B. , Bychkivska Yaryna , Frey Matthew H.Z. , Jeffrey Kristin D. , Sampaio Arthur V. , Underhill T. Michael , Johnson James D.
Published: November 2008

OBJECTIVE—Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of diabetes, but the roles of specific ER Ca2+ release channels in the ER stress–associated apoptosis pathway remain unknown. Here, we examined the effects of stimulating or inhibiting the ER-resident inositol trisphosphate receptors (IP3Rs) and the ryanodine receptors (RyRs) on the induction of β-cell ER stress and apoptosis.

RESEARCH DESIGN AND METHODS—Kinetics of β-cell death were tracked by imaging propidium iodide incorporation and caspase-3 activity in real time. ER stress and apoptosis were assessed by Western blot. Mitochondrial membrane potential was monitored by flow cytometry. Cytosolic Ca2+ was imaged using fura-2, and genetically encoded fluorescence resonance energy transfer (FRET)–based probes were used to measure Ca2+ in ER and mitochondria.

RESULTS—Neither RyR nor IP3R inhibition, alone or in combination, caused robust death within 24 h. In contrast, blocking sarco/endoplasmic reticulum ATPase (SERCA) pumps depleted ER Ca2+ and induced marked phosphorylation of PKR-like ER kinase (PERK) and eukaryotic initiation factor-2α (eIF2α), C/EBP homologous protein (CHOP)–associated ER stress, caspase-3 activation, and death. Notably, ER stress following SERCA inhibition was attenuated by blocking IP3Rs and RyRs. Conversely, stimulation of ER Ca2+ release channels accelerated thapsigargin-induced ER depletion and apoptosis. SERCA block also activated caspase-9 and induced perturbations of the mitochondrial membrane potential, resulting eventually in the loss of mitochondrial polarization.

CONCLUSIONS—This study demonstrates that the activity of ER Ca2+ channels regulates the susceptibility of β-cells to ER stress resulting from impaired SERCA function. Our results also suggest the involvement of mitochondria in β-cell apoptosis associated with dysfunctional β-cell ER Ca2+ homeostasis and ER stress.
Replication Study of Candidate Genes Associated With Type 2 Diabetes Based On Genome-Wide Screening
Authors: Tabara Yasuharu , Osawa Haruhiko , Kawamoto Ryuichi , Onuma Hiroshi , Shimizu Ikki , Miki Tetsuro , Kohara Katsuhiko , Makino Hideichi
Published: November 2008

OBJECTIVE—The present study was conducted to confirm possible associations between candidate genes from genome-wide association studies and type 2 diabetes in Japanese diabetic patients and a community-based general population. A total of 11 previously reported single-nucleotide polymorphisms (SNPs) from the TCF7L2, CDKAL1, HHEX, IGF2BP2, CDKN2A/B, SLC30A8, and KCNJ11 genes were analyzed.

RESEARCH DESIGN AND METHODS—Candidate SNPs were genotyped in 506 type 2 diabetic patients and 402 control subjects and meta-analyzed with six previous association studies in Japanese patients. Associations with fasting plasma insulin levels were investigated in a general population sample (n = 1,963, 61 ± 13 years).

RESULTS—In our case-control subjects, susceptibility to type 2 diabetes was replicated in TCF7L2 (rs12255372), CDKAL1 (rs7756992, rs7754840), HHEX (rs7923837), IGF2BP2 (rs4402960 and rs1470579), CDKN2A/B (rs10811661), and SLC30A8 (rs13266634). In addition to these polymorphisms, meta-analysis confirmed the association of type 2 diabetes susceptibility with KCNJ11 rs5219, TCF7L2 rs7903146, and HHEX rs1111875. The TCF7L2 rs12255372 polymorphism showed the highest odds ratio (OR) for type 2 diabetes (OR 1.714 [1.298–2.263]). Odds ratio of other polymorphisms ranged from 1.13 to 1.41. The risk allele of CDKAL1 rs7756992 was significantly associated with lower insulin levels in type 2 diabetic patients after adjustment for other confounding factors.

CONCLUSIONS—Type 2 diabetes susceptibility of seven candidate genes was confirmed in Japanese. Conservation of susceptible loci for type 2 diabetes was independent of ethnic background.
Feasibility of 10-Day Use of a Continuous Glucose-Monitoring System in Adults With Type 1 Diabetes
Authors: Garg Satish K. , Voelmle Mary K. , Gottlieb Peter
Published: November 2008

OBJECTIVE—The purpose of this pilot study was to evaluate the feasibility of 10-day use of a transcutaneous, real-time, continuous glucose-monitoring (CGM) system. All previous reports using different CGM systems were for 3-, 5-, or 7-day use.

RESEARCH DESIGN AND METHODS—On day 1, subjects received the CGM device (SEVEN System) and underwent training on proper use. Subjects returned to the clinic on days 2, 7, and 10 for in-clinic sessions. On days 2 and 7, half the subjects performed fingersticks every 15 min and the other half had Yellow Springs Instruments (YSI) samples drawn every 15 min. On day 10, all subjects participated in an 8-h in-clinic session with YSI and fingerstick testing.

RESULTS—The median absolute relative difference for CGM versus YSI was 12.6, 11.3, and 14.5% on days 2, 7, and 10, respectively (P = 0.63). CGM performed better on day 10 when compared with self-monitoring of blood glucose as compared with YSI.

CONCLUSIONS—This is the first study to document 10-day use of a 7-day CGM system.
Comparison of endoscopic and microscopic removal of pituitary adenomas: single-surgeon experience and the learning curve
Authors: O'Malley Bert W. , Grady M. Sean , Gabel Brandon C. , Cohen Marc A. , Heuer Gregory G. , Pisapia Jared , Bohman Leif-Erik , Leibowitz Jason M.
Published: November 2008

Object

The endoscopic endonasal approach for resection of pituitary lesions is an effective surgical option for tumors of the sella turcica. In this study the authors compared outcomes after either purely endoscopic resection or traditional microscope-aided resection. They also attempted to determine the learning curve associated with a surgical team converting to endoscopic techniques.

Methods

Retrospective data were collected on patients who were surgically treated for a pituitary lesion at the Hospital of the University of Pennsylvania between July 2003 and May 2008. Age, sex, race, presenting symptoms, length of hospital stay, surgical approach, duration of surgery, tumor pathological features, gross-total resection (GTR) of tumor, recurrence of the lesion, and intraoperative and postoperative complications were noted. All procedures were performed by the same senior neurosurgeon, who was initially unfamiliar with the endoscopic endonasal approach.

Results

A total of 25 patients underwent microscopic resection and 25 patients underwent endoscopic resection performed by a single skull base team consisting of the same senior neurosurgeon and otorhinolaryngologist (M.S.G. and B.W.O.). In the microscopically treated cohort, there were 8 intra- or postoperative complications, 6 intraoperative CSF leaks, 17 (77%) of 22 patients had GTR on postoperative imaging, 5 patients underwent ≥ 2 operations, and 10 (59%) of 17 patients reported total symptom resolution at follow-up. The endoscopically treated group had 7 intraor postoperative complications and 7 intraoperative CSF leaks. Of the patients who had pre- and postoperative imaging studies, 14 (66%) of 21 endoscopically treated patients had GTR; 4 patients had ≥ 2 operations, and 10 (66%) of 15 patients reported complete symptom resolution at follow-up. The first 9 patients who were treated endoscopically had a mean surgical time of 3.42 hours and a mean hospital stay of 4.67 days. The next 8 patients treated had a mean surgical time of 3.11 hours and a mean hospital stay of 3.13 days. The final 8 patients treated endoscopically had a mean surgical time of 2.22 hours and a mean hospital stay of 3.88 days. The difference in length of operation between the first 9 and the last 8 patients treated endoscopically was significantly different. There was a trend toward decreased CSF leaks and other complications from the first 2 groups compared with the third group.

Conclusions

In this subset of patients, the use of endoscopic endonasal resection results in a similar complication and symptom resolution rate compared with traditional techniques. The authors postulate that the learning curve for endoscopic resection can be ≤ 17 procedures.
Dural relationships of Meckel cave and lateral wall of the cavernous sinus
Authors: Janjua Rashid M. , Al-Mefty Ossama , Densler Duane W. , Shields Christopher B.
Published: November 2008

Object

The purpose of this study was to elucidate the anatomy of the trigeminal nerve (cranial nerve [CN] V), Meckel cave (MC), and lateral wall of the cavernous sinus (CS).

Methods

Ten fresh cadaver heads (20 sides) and 2 middle fossa embalmed specimens were removed, decalcified, sectioned, stained, and studied microscopically.

Results

In the MC, the posterior fossa meningeal dura extended into the middle fossa surrounding CN V. The average medial length of the MC was 16.7 mm and the lateral length was 13.5 mm. The dural roof of MC was thicker than its floor and was covered by a paw-shaped fibrous tissue extending from the tentorium to the ganglion (in 100% of specimens). Between the dural sleeve of the MC and venous space of the CS, a separate fibrous wall could be identified in 45% (9 of 20) extending between the tentorium and the floor of the CS. The mean length of CN V in the MC proximal to the posterior margin of the Gasserian ganglion was 11.8 mm. The mean length of CN V1 was 19.4 mm; V2, 12.3 mm; and V3, 7.4 mm distal to the anterior margin of the ganglion. The periosteal dura followed the bone of the middle fossa and was continuous with the extracranial periosteum.

The lateral dural wall of the CS consisted of a medial (membranous) and a lateral wall. The latter was separated into a thin outer layer and a thicker fibrous inner layer that became thinner as it extended posterolaterally.

Conclusions

The MC is an extension of the posterior fossa dura with intricate relationships with the surrounding dural layers.
Surgical management of trigeminal schwannomas
Authors: Ramina Ricardo , Mattei Tobias A. , Sória Marília G. , da Silva Erasmo B. , Leal André G. , Neto Maurício C. , Fernandes Yvens B.
Published: November 2008

Object

The authors provide a detailed review of the surgical management of trigeminal schwannomas (TSs) and also discuss the best surgical approach based on the surgical anatomy and tumor extension.

Methods

A series of 17 patients with TSs who were surgically treated between 1987 and 2008 at the authors' institution is reported. The lesions were small (< 3 cm) in 2, medium (between 3 and 4 cm) in 5, large (> 4 cm) in 6, and giant (> 5 cm) in 4 cases. Preoperative symptoms included trigeminal hypesthesia (53%), facial pain (53%), headaches (35.3%), hearing impairment (17.6%), seizures (17.6%), diplopia (11.8%), ataxia (11.8%), and hemiparesis and increased intracranial pressure with papilledema (5.9%). The mean follow-up duration was 10.5 years (121.6 months), with an average of 0.8 patients per year.

Results

Total tumor excision was possible in 16 patients, with no surgery-related deaths. Postoperative trigeminal anesthesia was observed in 7; trigeminal motor function was preserved in 7. Two developed cerebrospinal fluid leakage, 2 presented with mild facial palsy, and 1 patient with neurofibromatosis Type 2 had recurrence of the tumor, which was uneventfully removed. Of the 9 who reported facial pain, only 1 remained symptomatic postoperatively.

Conclusions

The best treatment for TSs is complete microsurgical removal. Postoperative preservation of trigeminal nerve function is possible when resection of the lesion is performed at well-established skull base neurosurgical centers. Although good results have been reported with radiosurgery, no cure can be obtained with this therapeutic modality. Instead, this treatment should be reserved only for nonresectable and residual tumors within the cavernous sinus.
Contralateral far-lateral approach for clipping of a ruptured vertebral artery–posterior inferior cerebellar artery aneurysm
Authors: Bragg Taryn McFadden , Duckworth Edward A. M.
Published: November 2008

Numerous nuanced approaches have been used to access posterior inferior cerebellar artery (PICA) aneurysms for microsurgical clipping. The authors report the case of a patient with a right vertebral artery (VA)–PICA aneurysm that was reached via a contralateral far-lateral approach. The wide-necked saccular/fusiform aneurysm arose from the lateral aspect of the right V4 segment just proximal to the PICA origin, anterior to the jugular tubercle at the level of the hypoglossal canal. Computed tomography angiograms demonstrated the size and configuration of the aneurysm, and 3D reconstructions revealed the tortuosity of the right VA, defining its location just left of the midline adjacent to the lower clivus.

A contralateral far-lateral approach to VA–PICA aneurysms should be considered when aneurysms cross the midline. Computed tomography angiography with volume rendering and interactive software capabilities can help identify the relationship of such an aneurysm to an individual's particular skull base osseous anatomy and is paramount in selecting the optimal microsurgical approach.
Conversion of external ventricular drains to ventriculoperitoneal shunts after aneurysmal subarachnoid hemorrhage: effects of site and protein/red blood cell counts on shunt infection and malfunction
Authors: Rammos Stylianos , Klopfenstein Jeffrey , Augsburger Lori , Wang Huan , Wagenbach Anne , Poston Jennifer , Lanzino Giuseppe
Published: November 2008

Object

The purpose of this study was to determine the incidence of shunt infection in patients with subarachnoid hemorrhage (SAH) after converting an external ventricular drain (EVD) to a ventriculoperitoneal (VP) shunt using the existing EVD site. The second purpose was to assess the risk of shunt malfunction after converting the EVD to a permanent shunt irrespective of the cerebrospinal fluid (CSF) protein and red blood cell (RBC) counts.

Methods

Data obtained in 80 consecutive adult patients (18 men and 62 women, mean age 60.8 years, range 33–85 years) who underwent direct conversion of an EVD to a VP shunt for post-SAH hydrocephalus between August 2002 and March 2007 were retrospectively reviewed. In each patient, the existing EVD site was used to pass the proximal shunt catheter. In no patient was VP shunt insertion delayed based on preoperative RBC or protein counts.

Results

The mean period of external ventricular drainage before VP shunt placement was 14.1 days (range 3–45 days). No patient suffered ventriculitis. The mean perioperative CSF protein level was 124 mg/dl (range 17–516 mg/dl). The mean and median perioperative RBC values in CSF were 14,203 RBCs/mm3 and 4600 RBCs/mm3 (range 119–290,000/mm3), respectively. No patient was lost to follow-up. The mean follow-up duration was 24 months (range 2–53 months). Three patients (3.8%) had shunt malfunction related to obstruction of the shunt system after 15 days, 2 months, and 18 months, respectively. There were no shunt-related infections. No patient suffered a clinically significant hemorrhage from ventricular catheter placement after VP shunt insertion.

Conclusions

In adult patients with aneurysmal SAH, conversion of an EVD to a VP shunt can be safely done using the same EVD site. In this defined patient population, protein and RBC counts in the CSF do not seem to affect shunt survival adversely. Thus, conversion of an EVD to VP shunt should not be delayed because of an elevated protein or RBC count.
Clipping of very large or giant unruptured intracranial aneurysms in the anterior circulation: an outcome study
Authors: Hauck Erik F. , Wohlfeld Bryan , Welch Babu Guai , White Jonathan A. , Samson Duke
Published: November 2008

Object

Patients with very large or giant unruptured intracranial aneurysms present with ischemic stroke and progressive disability. The aneurysm rupture risk in these patients is extreme—up to 50% in 5 years. In this study the authors investigated the outcome of surgical treatment for these very large aneurysms in the anterior circulation.

Methods

Clinical data on 62 patients who underwent surgery for unruptured aneurysms (20–60 mm) between 1998 and 2006 were reviewed.

Results

Complete aneurysm occlusion (100%) was achieved in 90% of cases, near complete occlusion (90–99%) in 5%. The surgical risk in patients younger than 50 years of age was 8% (Glasgow Outcome Scale score of 1 or 3 within 1 year after surgery). In older patients, the risk increased with advancing age.

Conclusions

The treatment of very large or giant unruptured intracranial aneurysms is hazardous and complex and thus best performed only at major cerebrovascular centers with an experienced team of neurosurgeons, interventional neuroradiologists, neurologists, and neuroanesthesiologists. Surgery, with acceptable risks and excellent occlusion rates, is typically the treatment of choice in patients younger than 50 years of age. In older patients, the benefits of endovascular treatment versus surgery versus no treatment must be carefully weighed individually. Minimizing temporary occlusion and the consequent use of intraoperative angiography may help reduce surgical complications.
Brain oxygen tension and outcome in patients with aneurysmal subarachnoid hemorrhage
Authors: Ramakrishna Rohan , Stiefel Michael , Udoteuk Joshua , Spiotta Alejandro , Levine Joshua M. , Kofke W. Andrew , Zager Eric , Yang Wei , LeRoux Peter
Published: November 2008

Object

Poor outcome is common after aneurysmal subarachnoid hemorrhage (SAH). Clinical studies suggest that cerebral hypoxia after traumatic brain injury is associated with poor outcome. In this study we examined the relationship between brain oxygen tension (PbtO2) and death after aneurysmal SAH.

Methods

Forty-six patients, including 34 women and 12 men (Glasgow Coma Scale Score ≤ 8 and median age 58.5 years) who underwent PbtO2 monitoring were studied prospectively during a 2-year period in a neurosurgical intensive care unit at a University Level I Trauma Center. Brain oxygen tension, intracranial pressure (ICP), mean arterial pressure, cerebral perfusion pressure (CPP), and brain temperature were continuously monitored, and treatment was directed toward ICP, CPP, and PbtO2 targets. The relationship between PbtO2 and 1-month survival was examined.

Results

Data were available from 5424 hours of PbtO2 monitoring. For the entire cohort the mean ICP, CPP, and PbtO2 were 13.85 ± 2.40, 84.05 ± 3.41, and 30.79 ± 1.91 mm Hg, respectively. Twenty-five patients died (54%). The mean daily PbtO2 was higher in survivors than nonsurvivors (33.94 ± 2.74 vs 28.14 ± 2.59 mm Hg; p = 0.05). In addition, survivors had significantly shorter episodes of compromised PbtO2 (defined as 15–25 mm Hg) than nonsurvivors (125.85 ± 15.44 vs 271.14 ± 55.23 minutes; p < 0.01). Intracranial pressure was similar in survivors and nonsurvivors. In contrast, the average CPP was significantly lower in nonsurvivors than survivors (76.96 ± 5.50 vs 92.49 ± 2.75 mm Hg; p = 0.01). When PbtO2 was stratified according to CPP level, survivors had higher PbtO2 levels. Following logistic regression, the number of episodes of compromised PbtO2 (odds ratio 1.1, 95% confidence interval 1.003–1.2) and number of episodes of cerebral hypoxia (< 15 mm Hg; odds ratio 1.3, 95% confidence interval 1.0–1.7) were more frequent in those who died.

Conclusions

Patient deaths after SAH may be associated with a lower mean PbtO2 and longer periods of compromised cerebral oxygenation than in survivors. This knowledge may be used to help direct therapy.
A very unusual case of fibromuscular dysplasia with multiple aneurysms of the vertebral artery and posterior inferior cerebellar artery
Authors: Kimura Hidehito , Hosoda Kohkichi , Hara Yoshie , Kohmura Eiji
Published: November 2008

Fibromuscular dysplasia (FMD) is a noninflammatory and nonatheromatous arteriopathy that commonly affects the renal and cervical internal carotid arteries and sometimes the vertebral arteries (VAs). The association of FMD with intracranial aneurysms is widely known. The authors describe a rare case of FMD presenting with subarachnoid hemorrhage due to the rupture of 1 of 10 aneurysms located in the extra- and intracranial vertebral and posterior inferior cerebellar arteries. The FMD was treated successfully using flow reversal therapy, consisting of proximal occlusion of the VA with Guglielmi detachable coils, and was diagnosed histopathologically using a biopsy specimen of the distal superficial temporal artery. Originally FMD may be caused by a fragile arterial wall that may progress to the formation of an aneurysm due to hemodynamic stress. For this reason, FMD may be treatable by reducing this hemodynamic stress.
In vivo assessment of rapid cerebrovascular morphological adaptation following acute blood flow increase
Authors: Hoi Yiemeng , Gao Ling , Tremmel Markus , Paluch Rocco A. , Siddiqui Adnan H. , Meng Hui , Mocco J
Published: November 2008

Object

Pathological extremes in cerebrovascular remodeling may contribute to basilar artery (BA) dolichoectasia and fusiform aneurysm development. Factors regulating cerebrovascular remodeling are poorly understood. To better understand hemodynamic influences on cerebrovascular remodeling, we examined BA remodeling following common carotid artery (CCA) ligation in an animal model.

Methods

Rabbits were subjected to sham surgery (3 animals), unilateral CCA ligation (3 animals), or bilateral CCA ligation (5 animals). Transcranial Doppler ultrasonography and rotational angiography were used to compute BA flow, diameter, wall shear stress (WSS), and a tortuosity index on Days 0, 1, 4, 7, 14, 28, 56, and 84. Basilar artery tissues were stained and analyzed at Day 84. Statistical analysis was performed using orthogonal contrast analysis, repeated measures analysis of variance, or mixed regression analysis of repeated measures. Statistical significance was defined as a probability value < 0.05.

Results

Basilar artery flow and diameter increased significantly after the procedure in both ligation groups, but only the bilateral CCA ligation group demonstrated significant differences between groups. Wall shear stress significantly increased only in animals in the bilateral CCA ligation group and returned to baseline by Day 28, with 52% of WSS correction occurring by Day 7. Only the bilateral CCA ligation group developed significant BA tortuosity, occurring within 7 days postligation. Unlike the animals in the sham and unilateral CCA ligation groups, the animals in the bilateral CCA ligation group had histological staining results showing a substantial internal elastic lamina fragmentation.

Conclusions

Increased BA flow results in adaptive BA remodeling until WSS returns to physiological baseline levels. Morphological changes occur rapidly following flow alteration and do not require chronic insult to affect substantial and significant structural transformation. Additionally, it appears that there exists a flow-increase threshold that, when surpassed, results in significant tortuosity.
Endothelial molecular changes in a rodent model of arteriovenous malformation
Authors: Karunanyaka Athula , Tu Jian , Watling Amy , Storer Kingsley P. , Windsor Apsara , Stoodley Marcus A.
Published: November 2008

Object

The cellular and molecular processes underlying arteriovenous malformation (AVM) development and response to radiosurgery are largely unknown. An animal model mimicking the molecular properties of AVMs is required to examine these processses. This study was performed to determine whether the endothelial molecular changes in an animal model of arteriovenous fistula (AVF) are similar to those in human AVMs.

Methods

Arteriovenous fistulas were created in 18 Sprague–Dawley rats by end-to-side anastomosis of the left jugular vein to the common carotid artery creating a model “nidus” of arterialized branching veins that coalesce into a “draining vein” (sigmoid sinus). Six control animals underwent sham operations.

Results

After 1 or 3 days, or 1, 3, 6, or 12 weeks, fresh-frozen sections of the fistula, nidus vessels, and contralateral vessels were studied immunohistochemically for thrombomodulin, von Willebrand factor, E-selectin, P-selectin, and vascular endothelial growth factor.

Conclusions

The AVF model has a “nidus” with endothelial molecular changes similar to those observed in human AVMs, supporting its use as a model for studying the effects of radiosurgery on AVMs.
Surgical construction of a novel simulated carotid siphon in dogs
Authors: Tan Hua-Qiao , Li Ming-Hua , Zhu Yue-Qi , Fang Chun , Wu Chun-Geng , Cheng Ying-Sheng , Wang Jue , Xie Jian , Zhang He
Published: November 2008

Object

The development and preclinical assessment of new endovascular devices necessitate readily available and reproducible animal models. The purpose of this study was to develop an in vivo carotid siphon model for testing the properties of covered stents specially designed for the intracranial vasculature.

Methods

Six carotid siphon–shaped devices were created. Six dogs underwent surgery to expose and isolate both common carotid arteries (CCAs). The right CCA origin was ligated and incised distal to the ligation point after temporary constriction of the distal right CCA. The distal left CCA was ligated and incised proximal to the ligation point after the left CCA origin was temporarily clamped. The proximal isolated left CCA was passed through the shaped device and then anastomosed end-to-end to the distal isolated right CCA. Finally, the shaped device was fixed and embedded in the neck. Intraarterial digital subtraction angiography was performed at 7 days, 2 weeks, and 1 month postprocedure. All models underwent endovascular interventional simulation. The carotid siphon models were evaluated.

Results

The animals tolerated the surgical procedure well. The mean time for surgical construction of the model was 90 minutes. The morphology and endovascular manipulation of the siphon models were similar to those in humans. Stenosis of anastomotic stoma occurred in 2 models, and mural thrombosis of anastomotic stoma occurred in 1 model; however, all models were patent at postprocedural follow-up angiography.

Conclusions

Surgical construction of an in vivo carotid siphon model in dogs with carotid siphon–shaped devices is feasible and potentially useful for testing neurovascular devices.
Circumferential fusion for cervical kyphotic deformity
Authors: Mummaneni Praveen V. , Dhall Sanjay S. , Rodts Gerald E. , Haid Regis W.
Published: November 2008

Object

The treatment of cervical kyphotic deformity is challenging. Few prior reports have examined combined anterior/posterior correction methods, and fusion rates and standardized outcomes are rarely cited in literature examining these techniques. The authors present their midterm results with cervical kyphosis correction.

Methods

The authors retrospectively reviewed the charts of 30 patients with cervical kyphotic deformity who underwent circumferential spine surgery between 2001 and 2007. The causes of the deformity included chronic fracture in 17 patients, degenerative disease in 10, and tumor in 3. Anterior procedures included discectomies and corpectomies/osteotomies at 1 or more levels with fusion. Posterior operations included decompression and/or osteotomies with lateral mass or pedicle fixation. Preoperative and postoperative Ishihara kyphosis indices, modified Japanese Orthopaedic Association (mJOA) scores, and Nurick grades were analyzed. Arthrodesis was assessed via dynamic radiographs, and CT scans were used to assess fusion in questionable cases.

Results

One patient was lost to follow-up. Two patients died within 1 month of surgery. The follow-up period in the remaining 27 patients ranged from 1 to 6.4 years (mean 2.6 years). Ishihara indices improved from a preoperative mean of −17.7 to a postoperative mean of +11.4. The mean Nurick grades improved from 3.2 preoperatively to 1.3 postoperatively. The mJOA scores improved from a preoperative mean of 10 to 15 postoperatively. All surviving patients who underwent follow-up showed postoperative fusion except 1 patient with renal failure and osteoporosis (95% fusion rate). The overall rate of complications (major and minor) was 33.3%.

Conclusions

In cases of cervical kyphosis, management with decompression, osteotomy, and stabilization from both anterior and posterior approaches can restore cervical lordosis. Furthermore, such surgical techniques can produce measurable improvements in neurological function (as measured with Nurick grades and mJOA scores) and achieve high fusion rates. However, there is a significant rate of complications.
Spatially distributed temperatures at the base of two mountain snowpacks measured with fiber-optic sensors
Authors: Tyler Scott W. , Burak Susan A. , McNamara James P. , Lamontagne Aurele , Selker John S. , Dozier Jeff
Published: November 2008

Snowpack base temperatures vary during accumulation and diurnally. Their measurement provides insight into physical, biological and chemical processes occurring at the snow/soil interface. Recent advances in Raman-spectra instruments, which use the scattered light in a standard telecommunications fiber-optic cable to infer absolute temperature along the entire length of the fiber, offer a unique opportunity to obtain basal snow temperatures at resolutions of 1 m, 10 s and 0.1°C. Measurements along a 330 m fiber over 24 hours during late-spring snowmelt at Mammoth Mountain, California, USA, showed basal snow temperatures of 0 ± 0.2°C using 10 s averages. Where the fiber-optic cable traversed bare ground, surface temperatures approached 40°C during midday. The durability of the fiber optic was excellent; no major damage or breaks occurred through the winter of burial. Data from the Dry Creek experimental watershed in Idaho across a small stream valley showed little variability of temperature on the northeast-facing, snow-covered slope, but clearly showed melting patterns and the effects of solar heating on southwest-facing slopes. These proof-of-concept experiments show that the technology enables more detailed spatial and temporal coverage than traditional point measurements of temperature.
Synchronous retreat and acceleration of southeast Greenland outlet glaciers 2000–06: ice dynamics and coupling to climate
Authors: Howat Ian M. , Joughin Ian , Fahnestock Mark , Smith Benjamin E. , Scambos Ted A.
Published: November 2008

A large portion of the recent increase in the rate of mass loss from the Greenland ice sheet is from increased outlet glacier discharge along its southeastern margin. While previous investigations of the region’s two largest glaciers suggest that acceleration is a dynamic response to thinning and retreat of the calving front, it is unknown whether this mechanism can explain regional acceleration and what forcing is responsible for initiating rapid thinning and retreat. We examine seasonal and interannual changes in ice-front position, surface elevation and flow speed for 32 glaciers along the southeastern coast between 2000 and 2006. While substantial seasonality in front position and speed is apparent, nearly all the observed glaciers show net retreat, thinning and acceleration, with speed-up corresponding to retreat. The ratio of retreat to the along-flow stress-coupling length is proportional to the relative increase in speed, consistent with typical ice-flow and sliding laws. This affirms that speed-up results from loss of resistive stress at the front during retreat, which leads to along-flow stress transfer. Large retreats were often preceded by the formation of a flat or reverse-sloped surface near the front, indicating that subsequent retreats were influenced by the reversed bed slope. Many retreats began with an increase in thinning rates near the front in the summer of 2003, a year of record high coastal-air and sea-surface temperatures. This anomaly was driven in part by recent warming, suggesting that episodes of speed-up and retreat may become more common in a warmer climate.
Different Magnitudes of Tensile Strain Induce Human Osteoblasts Differentiation Associated with the Activation of ERK1/2 Phosphorylation
Authors: Zhu Junfeng , Zhang Xiaoling , Wang Chengtao , Peng Xiaochun , Zhang Xianlong
Published: November 2008

Mechanical factors are related to periprosthetic osseointegration following total hip arthroplasty. However, osteoblast response to strain in implanted femurs is unclear because of the absence of accurate stress-measuring methods. In our study, finite element analysis was performed to calculate strain distribution in implanted femurs. 0.8- 3.2% tensile strain was then applied to human osteoblasts. Higher magnitudes of strain enhanced the expression of osteocalcin, type I collagen, and Cbfa1/Runx2. Lower magnitudes significantly increased ALP activity. Among these, type I collagen expression increased with the activation of ERK1/2 phosphorylation in a strainmagnitude-dependent manner. Our study marks the first investigation of osteoblast response at different magnitudes of periprosthetic strain. The results indicate that the functional status of human osteoblasts is determined by strain magnitude. The strain distribution in the proximal region of implanted femur should be improved for osseointegration.
Recognition Properties and Competitive Assays of a Dual Dopamine/Serotonin Selective Molecularly Imprinted Polymer
Authors: Suedee Roongnapa , Seechamnanturakit Vatcharee , Suksuwan Acharee , Canyuk Bhutorn
Published: November 2008

A molecularly imprinted polymer (MIP) with dual dopamine/serotonin-like binding sites (DS-MIP) was synthesized for use as a receptor model of study the druginteraction of biological mixed receptors at a molecular level. The polymer material was produced using methacrylic acid (MAA) and acrylamide (ACM) as functional monomers, N,N′-methylene bisacrylamide (MBAA) as cross-linker, methanol/water mixture (4:1, v/v) as porogen and a mixture of dopamine (D) and serotonin (S) as templates. The prepared DS-MIP exhibited the greatest rebinding of the template(s) in aqueous methanol solution with decreased recognition in acetonitrile, water and methanol solvent. The binding affinity and binding capacity of DS-MIP with S were found to be higher than those of DS-MIP with D. The selectivity profiles of DS-MIP suggest that the D binding site of DS-MIP has sufficient integrity to discriminate between species of non-optimal functional group orientation, whilst the S binding site of DS-MIP is less selective toward species having structural features and functional group orientations different from S. The ligand binding activities of a series of ergot derivatives (ergocryptine, ergocornine, ergocristine, ergonovine, agroclavine, pergolide and terguride) have been studied with the DS-MIP using a competitive ligand binding assay protocol. The binding affinities of DSMIP were demonstrated in the micro- or submicro-molar range for a series of ergot derivatives, whereas the binding affinities were considerably greater to natural receptors derived from the rat hypothalamus. The DS-MIP afforded the same pattern of differentiation as the natural receptors, i.e. affinity for the clavines > lysergic acid derivatives > ergopeptines. The results suggest that the discrimination for the ergot derivatives by the dopamine and serotonin sites of DS-MIP is due to the structural features and functional orientation of the phenylethylamine and indolylethylamine entities at the binding sites, and the fidelity of the dopamine and serotonin imprinted cavities.
Genome scan in sibling pairs with juvenile‐onset mood disorders: Evidence for linkage to 13q and Xq
Authors: Wigg Karen , Feng Yu , Gomez Lissette , Kiss Eniko , Kapornai Krisztina , Tamás Zsuzsa , Mayer László , Baji Ildikó , Daróczi Gabriella , Benák István , Osváth Viola Kothencné , Dombovári Edit , Kaczvinszk Emília , Besnyő Márta , Gádoros Julia , King Nicole , Székely Judit , Kovacs Maria , Vetró Ágnes , Kennedy James L. , Barr Cathy L.
Published: November 2008

Mood disorders (bipolar and depressive disorders) in children and adolescents are associated with significant morbidity and mortality. Twin and family studies, for the most part, indicate higher familiality and heritability for mood disorders that onset in childhood/adolescence than those that onset in adulthood. To identify the genetic contribution to mood disorders that onset in childhood/adolescence, we performed a genome scan on 146 nuclear families from Hungary containing an affected proband and affected siblings. In total, the pedigrees contained 303 affected children: 146 probands, 137 siblings with a first episode of mood disorder before 14.9 years of age, and 20 siblings with onset of their first episode after 14.9 years of age but before the age of 18. The results of the genome scan using 405 microsatellite markers did not provide evidence for linkage at the recommended genome wide significance level for any novel loci. However, markers on two chromosomes, 13q and Xq, provided evidence for linkage in regions previously identified as linked to bipolar disorder in multiple studies. For the marker on chromosome 13q the peak non‐parametric multipoint LOD score was at the marker D13S779 (LOD = 1.5, P = 0.004). On chromosome Xq, evidence for linkage was observed across a large region spanning two regions previously linked to bipolar disorder; Xq24 to Xq28, with a peak at marker TTTA062 (LOD 2.10, P = 0.0009) in Xq28. Results for these regions exceed the recommended P‐value for a replication study of P < 0.01 and thus provide evidence for these two loci as contributing to mood disorders with juvenile onset. © 2008 Wiley‐Liss, Inc.
Evidence supporting a role for the calcium‐sensing receptor in Alzheimer disease
Authors: Conley Yvette P. , Mukherjee Ankur , Kammerer Candace , DeKosky Steven T. , Kamboh M. Ilyas , Finegold David N. , Ferrell Robert E.
Published: November 2008

The calcium‐sensing receptor (CASR) is a G‐protein coupled, transmembrane receptor that responds to changes in Ca2+ levels. We hypothesized that the CASR could have a role in Alzheimer disease (AD) given expression of the CASR in brain, knowledge that calcium dysregulation promotes susceptibility to neuronal cell damage, the important role that the CASR plays in calcium regulation, and the fact that systemic calcium homeostasis and G‐protein signal transduction are altered in AD patients. To investigate the association of CASR variation in AD susceptibility, we genotyped a polymorphic dinucleotide repeat marker within intron 4, one SNP within the promoter region and three non‐synonymous SNPs within exon 7 of the CASR gene and tested for association analysis, using a well‐characterized cohort of AD cases (n = 692) and controls (n = 435). The dinucleotide repeat polymorphism was significantly associated with AD status (OR = 1.62; 95% CI: 1.27–2.07, P = 0.00037, Bonferroni corrected P = 0.0011) and the three non‐synonymous SNP haplotype was boarderline associated with AD status (P = 0.032, Bonferroni corrected P = 0.096). Stratifying by APOE4 allele carrier status revealed that the significant association was only in non‐APOE4 carriers (OR of 1.90; 95% CI: 1.37–2.62, P = 0.0001). We also investigated whether apoE or β amyloid could activate the calcium‐sensing receptor. The receptor activation assays revealed that apoE as well as β amyloid activated the CASR and that the level of activation appeared to be isoform dependent for apoE. These data support our hypothesis that the CASR has a role in AD susceptibility, particularly in individuals without an APOE4 allele. © 2008 Wiley‐Liss, Inc.
Synthetic Study of (−)‐Norzoanthamine: Construction of the ABC Ring Moiety
Authors: Murata Yoshihisa , Yamashita Daisuke , Kitahara Katsushi , Minasako Yohei , Nakazaki Atsuo , Kobayashi Susumu
Published: November 2008

Throw your hat in the ring: A highly diastereoselective synthesis of the ABC rings of (−)‐norzoanthamine has been achieved starting from the (−)‐Hajos–Parrish ketone (see scheme). Three asymmetric quaternary carbon centers on the C ring were constructed by a 1,4‐addition, and an intramolecular Diels–Alder reaction provided a trans‐decalin scaffold on the AB rings.

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A Phosphine‐Mediated Conversion of Azides into Diazo Compounds
Authors: Myers Eddie L. , Raines Ronald T.
Published: November 2008

N2 the mild: Diazo compounds are extremely versatile intermediates for synthetic organic chemistry, but their synthesis can be challenging in the presence of delicate functional groups. The Staudinger ligation has inspired a mild method for the conversion of a broad range of azides into their diazo compound derivatives through an acyl triazene intermediate.

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