bluuebunny/crossref_metadata_2025 huggingface dataset:
Posttraumatic stress disorder in the family and friends of patients who have suffered spontaneous subarachnoid hemorrhage
Authors: Noble Adam J. , Schenk Thomas
Published: November 2008

Object

Significant others (SOs), such as spouses and life partners, of patients who have survived subarachnoid hemorrhage (SAH) can experience psychiatric symptoms and psychosocial disability. The cause of such symptoms has not been established. Authors of the present study analyzed whether posttraumatic stress disorder (PTSD) subsequent to a loved one's SAH is a plausible explanation for these symptoms.

Methods

The authors examined a large representative sample of 86 patient/SO pairs 3.5 months postictus. All SOs were evaluated using a diagnostic PTSD measure, and coping skills were assessed. The cognitive, physical, and emotional status of patients was comprehensively examined.

Results

Twenty-six percent of SOs met the diagnostic criteria for PTSD, which represents a 3-fold increase in the rate expected within the general population. To establish the cause of PTSD, a logistic regression was performed, and results of this test showed that the use of maladaptive coping strategies was the best predictor of the disorder. A patient's level of disability held no significant association with the development of PTSD in his or her SO.

Conclusions

The elevated incidence of PTSD in SOs helps to explain why these persons report concerning levels of psychiatric symptomatology and psychosocial disability. Greater attention must be given to an SO's adjustment to the experience of having a loved one suffer an SAH. This need is all the more pertinent given that SOs often act as informal caregivers and that PTSD could interfere with their ability to effectively minister. Because bad coping skills seem to be the main cause of PTSD, teaching SOs better strategies might prevent the disorder and any resulting psychosocial disability.
Spontaneous isolated convexity subarachnoid hemorrhage: presentation, radiological findings, differential diagnosis, and clinical course
Authors: Refai Daniel , Botros James A. , Strom Russell G. , Derdeyn Colin P. , Sharma Aseem , Zipfel Gregory J.
Published: November 2008

Object

The clinical characteristics and overall outcome in patients with spontaneous isolated convexity subarachnoid hemorrhage (SAH) are not well described in the literature. The purpose of this study was to examine the mode of presentation, common origins, radiographic findings, and clinical course in a large case series of such patients.

Methods

A retrospective single-center chart review of all patients in whom nontraumatic primary convexity SAH was diagnosed between 2002 and 2007 was performed. Twenty patients were identified and analyzed for presenting symptoms, radiological and laboratory findings, hospital course, and outcome.

Results

There were 15 women and 5 men in our series, and the mean age was 52 years (range 18–86 years). The most common presenting symptom was headache, with 15 patients experiencing it as a chief complaint. Other frequent manifestations included altered mental status (8 patients), focal neurological deficits (7), and seizure (4 patients). An underlying cause of the hemorrhage was identified in 13 cases, whereas the remainder went unresolved. Of the known causes, 5 were due to posterior reversible encephalopathy syndrome, 3 were caused by thrombocytopenia or anticoagulation, and the remainder were isolated cases of lupus vasculitis, drug-induced vasculopathy, postpartum cerebral angiopathy, hypertensive microangiopathy, and Call–Fleming syndrome. All patients with unknown disease origins had favorable outcomes, whereas 8 of 13 patients with an identifiable underlying disorder experienced favorable outcomes.

Conclusions

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.
Frequency and clinical impact of asymptomatic cerebral infarction due to vasospasm after subarachnoid hemorrhage
Authors: Schmidt J. Michael , Wartenberg Katja E. , Fernandez Andres , Claassen Jan , Rincon Fred , Ostapkovich Noeleen D. , Badjatia Neeraj , Parra Augusto , Connolly E. Sander , Mayer Stephan A.
Published: November 2008

Object

The authors sought to determine frequency, risk factors, and impact on outcome of asymptomatic cerebral infarction due to vasospasm after subarachnoid hemorrhage (SAH).

Methods

The authors prospectively studied 580 patients with SAH admitted to their center between July 1996 and May 2002. Delayed cerebral ischemia (DCI) from vasospasm was defined as 1) a new focal neurological deficit or decrease in level of consciousness, 2) a new infarct revealed by follow-up CT imaging, or both, after excluding causes other than vasospasm. Outcome at 3 months was assessed using the modified Rankin Scale.

Results

Delayed cerebral ischemia occurred in 121 (21%) of 580 patients. Of those with DCI, 36% (44 patients) experienced neurological deterioration without a corresponding infarct, 42% (51 patients) developed an infarct in conjunction with neurological deterioration, and 21% (26 patients) had a new infarct on CT without concurrent neurological deterioration. In a multivariate analysis, risk factors for asymptomatic DCI included coma on admission, placement of an external ventricular drain, and smaller volumes of SAH (all p ≤ 0.03). Patients with asymptomatic DCI were less likely to be treated with vasopressor agents than those with symptomatic DCI (64 vs 86%, p = 0.01). After adjusting for clinical grade, age, and aneurysm size, the authors found that there was a higher frequency of death or moderate-to-severe disability at 3 months (modified Rankin Scale Score 4–6) in patients with asymptomatic DCI than in patients with symptomatic DCI (73 vs 40%, adjusted odds ratio 3.9, 95% confidence interval 1.3–12.0, p = 0.017).

Conclusions

Approximately 20% of episodes of DCI after SAH are characterized by cerebral infarction in the absence of clinical symptoms. Asymptomatic DCI is particularly common in comatose patients and is associated with poor outcome. Strategies directed at diagnosing and preventing asymptomatic infarction from vasospasm in patients with poor-grade SAH are needed.
Polymorphism rs42524 of COL1A2 and sporadic intracranial aneurysms in the Chinese population
Authors: Zhu Yufang , Li Weiju , Ge Mingxu , Xu Shangchen , Zhao Guangyu , Wang Hanbin , Qian Haiyan , Zhu Ningxi , Pang Qi
Published: November 2008

Object

The COL1A2 gene at 7q22.1 has been shown to be associated with familial intracranial aneurysms (IAs) in the Japanese population. In the present study, the authors investigated the correlation between the presence of the rs42524 polymorphism in COL1A2 and the occurrence of sporadic IAs in Chinese patients.

Methods

The polymorphism rs42524 of the COL1A2 gene was identified by polymerase chain reaction–based restriction analysis in genomic DNA from 226 patients with sporadic IAs (mean age 51.49 ± 11.47 years) and 326 control participants (mean age 52.33 ± 10.50 years). Neurological assessments were performed using the Hunt and Hess grading system, and differences in allelic and genotypic frequencies between the patient and control groups were evaluated with the chi-square test.

Results

There was a significant difference in either the genotype distribution (χ2 = 11.99, p = 0.002) or allelic frequencies (χ2 = 11.96, p = 0.001, odds ratio 2.579, 95% confidence interval 1.486–4.476) between patients with IAs and patients in the control group.

Conclusions

The rs42524 polymorphism of COL1A2 could be a genetic risk factor for sporadic IAs among individuals of Chinese Han ethnicity. This study is the first to confirm the association between COL1A2 and IAs.
A case of multiple pial arteriovenous fistulas associated with dural arteriovenous fistula
Authors: Saito Atsushi , Sugawara Takayuki , Mikawa Shigeki , Akamatsu Yousuke , Saito Heisuke , Seki Hirofumi
Published: November 2008

Pial arteriovenous fistulas (AVFs) are known as rare cerebrovascular lesions. They are composed of ≥ 1 arterial feeding vessels and a single draining vein that usually has high perfusion pressure and generally occur in infants. Cases involving adults are very rare and the developmental mechanisms and natural history of these lesions remain unknown. The authors present a case of multiple pial AVFs in an adult in whom the lesions developed after radiosurgical treatment of dural AVFs. Direct disconnection of pial arterial supplies was performed, and the abnormal shunts were successfully eliminated. The authors report the clinical course of this case and discuss the characteristics of and treatment strategy for multiple pial AVFs, reviewing the published literature.
Intravascular ultrasonography-guided stent angioplasty of an extracranial vertebral artery dissection
Authors: Yoon Won-Ki , Kim Young-Woo , Kim Sang-Don , Park Ik-Seong , Baik Min-Woo , Kim Seong-Rim
Published: November 2008

The authors report on a case of intravascular ultrasonography (IVUS)-guided stent angioplasty for iatrogenic extracranial vertebral artery (VA) dissection in a 49-year-old man after coil embolization for an unruptured aneurysm of the right posterior inferior cerebellar artery. Insignificant dissections occurred during the procedure. Postoperatively, the patient experienced gradually worsening posterior neck pain and headache, and follow-up angiography 8 months after the coil embolization revealed expansion of the dissection. The patient underwent stent angioplasty with IVUS guidance and his symptoms improved.

To the authors' knowledge, this is the first report of IVUS-guided stent angioplasty of an extracranial VA dissection. It was safe and feasible to treat extracranial VA dissections with stent placement under IVUS guidance. Intravascular environments are in real time with IVUS, and this technique is useful in the confirmation of a true lumen and evaluation of appropriate stent apposition. More clinical experience with this technique is necessary and mandatory, and devices with smaller diameters with improved trackability are essential for further introduction of IVUS into the field of endovascular neurosurgery.
Developmental venous anomaly with symptomatic thrombosis of the draining vein
Authors: Walsh Michael , Parmar Hemant , Mukherji Suresh K. , Mamourian Alexander
Published: November 2008

Developmental venous anomalies (DVAs) are generally considered a benign and asymptomatic finding on CT and MR imaging. The authors report 2 cases of spontaneous thrombosis of the draining vein of a DVA depicted on CT and MR imaging. One patient presented with a nonhemorrhagic transient ischemia, which was successfully treated with anticoagulant therapy. The second patient presented with ischemia complicated by hemorrhagic conversion.
Middle cerebral artery branch occlusion mimicking a saccular aneurysm on 3D digital subtraction angiography
Authors: Pearl Monica Smith , Tamargo Rafael , Gailloud Philippe
Published: November 2008

The angiographic appearance of an intracranial arterial occlusion is typically distinct from that of a saccular aneurysm, with only a few reported cases of occlusion simulating aneurysm. At the same time, a small percentage of symptomatic intracranial aneurysms present with a stroke. Accurate diagnosis of these conditions is crucial, as their treatment differs. The authors report on a case of middle cerebral artery occlusion that mimicked the appearance of an aneurysm on angiography in the setting of acute stroke. The true diagnosis was not elucidated until repeated angiography 6 months later revealed recanalization of the previously occluded middle cerebral artery branch. This angiographic pitfall is important to consider when acute stroke is suspected as the mode of presentation of a saccular aneurysm.
Hemodynamic effects of recombinant human erythropoietin on the central nervous system after subarachnoid hemorrhage: reduction of microcirculatory impairment and functional deficits in a rabbit model
Authors: Murphy Amanda M. , Xenocostas Anargyros , Pakkiri Pria , Lee Ting-Yim
Published: November 2008

Object

The authors investigated the hemodynamic effects of recombinant human erythropoietin (rhEPO) after subarachnoid hemorrhage (SAH) in rabbits.

Methods

The authors used male New Zealand White rabbits in this study divided into the following groups: SAH plus saline (16 rabbits), SAH plus low-dose rhEPO (16 rabbits; 1500 IU/kg on Day 0 and 500 IU/kg on Days 2 and 4), SAH plus high-dose rhEPO (10 rabbits; 1500 IU/kg on Days 0, 2, 4, and 6), and sham (6 rabbits). Computed tomography perfusion studies and CT angiography were performed for 1 hour after SAH on Day 0, and once each on Days 2, 4, 7, 9, and 16 after SAH. Assessments of neurological function and tissue histology were also performed.

Results

The mortality rate was significantly lower after rhEPO treatment (12%) than after saline treatment (44%) (p < 0.05). Neurological outcomes in the low-dose and high-dose rhEPO groups were better than in the saline group after SAH (p < 0.05), and the cerebral blood flow in the high-dose rhEPO group was greater than that in the saline group (p < 0.05). The mean transit time was significantly lower on Days 2 and 4 in the low-dose and high-dose rhEPO groups than in the saline group, but increased significantly on Day 7 in both groups (p < 0.05). The hematocrit increased significantly from baseline values in the high-dose and low-dose rhEPO groups on Days 4 and 7, respectively (p < 0.05).

Conclusions

Treatment with rhEPO after experimental SAH is associated with improved cerebral blood flow and microcirculatory flow as reflected by lower mean transit times. Improved tissue perfusion correlated with reduced mortality and improved neurological outcomes. Further investigation of the impact of increasing hematocrit on hemodynamic changes is needed.
Atlantoaxial stabilization using multiaxial C-1 posterior arch screws
Authors: Donnellan Michael B. , Sergides Ioannis G. , Sears William R.
Published: November 2008

The authors present a novel technique of atlantoaxial fixation using multiaxial C-1 posterior arch screws. The technique involves the insertion of bilateral multiaxial C-1 posterior arch screws, which are connected by crosslinked rods to bilateral multiaxial C-2 pars screws. The clinical results are presented in 3 patients in whom anomalies of the vertebral arteries, C-1 lateral masses, and/or posterior arch of C-1 presented difficulty using existing fixation techniques with transarticular screws, C-1 lateral mass screws, or posterior wiring. The C-1 posterior arch screws achieved solid fixation and their insertion appeared to be technically less demanding than that of transarticular or C-1 lateral mass screws. This technique may reduce the risk of complications compared with existing techniques, especially in patients with anatomical variants of the vertebral artery, C-1 lateral masses, or C-1 posterior arch. This technique may prove to be an attractive fixation option in patients with normal anatomy.
Compensatory cerebral adaptations before and evolving changes after surgical decompression in cervical spondylotic myelopathy
Authors: Dong Yun , Holly Langston T. , Albistegui-Dubois Richard , Yan Xiaohong , Marehbian Jonathan , Newton Jennifer M. , Dobkin Bruce H.
Published: November 2008

Object

The goal of this study was to compare cortical sensorimotor adaptations associated with neurological deterioration and then recovery following surgical decompression for cervical spondylotic myelopathy (CSM).

Methods

Eight patients with CSM underwent functional MR (fMR) imaging during wrist extension and the 3-finger pinch task, along with behavioral assessments before and 3 and 6 months after surgery. Six healthy control volunteers were scanned twice.

Results

Cervical spine MR imaging demonstrated successful cord decompression. The patients improved after surgery on the modified Japanese Orthopaedic Association score for the upper extremity, which correlated with the changes in task-associated activation in specific sensorimotor regions of interest. Pinch-related activation in sensorimotor cortex contralateral to the movement paradigm was reduced before surgery then increased toward the extent of healthy controls after surgery. Before surgery, patients showed broader activation in ipsilateral sensorimotor cortex during wrist extension than during pinch, but activations became similar to those of healthy controls after surgery. Pinch-related activation volume in the ipsilateral sensorimotor cortex and the magnitude of activation in the contralateral dorsal premotor cortex evolved linearly across time after surgery, along with wrist extension–related activation magnitude in the contralateral supplementary motor area.

Conclusions

Serial fMR imaging studies in CSM can capture the adaptations in specific sensorimotor cortices that accompany clinical deterioration and postsurgical improvement in sensorimotor function associated with damage and partial recovery of conduction in corticospinal pathways. These adaptive regions can be monitored by serial fMR imaging to detect a critical loss of supraspinal reserve in compensatory plasticity, which might augment clinical information about the need for surgical decompression.
Thecal shunt placement for treatment of obstructive primary syringomyelia
Authors: Lam Sandi , Batzdorf Ulrich , Bergsneider Marvin
Published: November 2008

Object

The most commonly reported treatment of primary syringomyelia has been laminectomy with duraplasty or direct shunting from the syrinx cavity. Diversion of cerebrospinal fluid (CSF) from the spinal subarachnoid space to peritoneal, atrial, or pleural cavities has been described previously in only a few case reports. Shunting of the CSF from the subarachnoid space rostral to the level of myelographic blockage may reduce the filling force of the syrinx cavity and avoids myelotomy and manipulation of the spinal cord parenchyma. The authors report on 7 patients who underwent thecal shunt placement for primary spinal syringomyelia.

Methods

This study is a retrospective review of a consecutive series. The authors reviewed the medical records and neuroimaging studies of 7 adult patients with posttraumatic, postsurgical, or postinflammatory syringomyelia treated with thecoperitoneal, thecopleural, or thecoatrial shunt placement at the University of California Los Angeles Medical Center. Myelographic evidence of partial or complete CSF flow obstruction was confirmed in the majority of patients. The mean duration of follow-up was 33 months (range 6–104 months).

Results

Six (86%) of 7 patients showed signs of clinical improvement, whereas 1 remained with stable clinical symptoms. Of the 6 patients with available postoperative imaging, each demonstrated a reduction in syrinx size. Three patients (43%) had ≥ 1 complication, including shunt-induced cerebellar tonsillar descent in 1 patient and infections in 2.

Conclusions

If laminectomy with duraplasty is not possible for the treatment of primary syringomyelia, placement of a thecoperitoneal shunt (or thecal shunt to another extrathecal cavity) should be considered. Although complications occurred in 3 of 7 patients, the complication rate was outweighed by a relatively high symptomatic and imaging improvement rate.
Risk factors for closure of lamina after open-door laminoplasty
Authors: Matsumoto Morio , Watanabe Kota , Tsuji Takashi , Ishii Ken , Takaishi Hironari , Nakamura Masaya , Toyama Yoshiaki , Chiba Kazuhiro
Published: November 2008

Object

This retrospective study was conducted to evaluate the prevalence and clinical consequences of postoperative lamina closure after open-door laminoplasty and to identify the risk factors.

Methods

Eighty-two consecutive patients with cervical myelopathy who underwent open-door laminoplasty without plates or spacers in the open side (Hirabayashi's original method) were included (62 men and 20 women with a mean age of 62 years and a mean follow-up of 1.8 years). In 67 patients the cause of cervical myelopathy was spondylotic myelopathy, and in 15 it was caused by ossification of posterior longitudinal ligament. Radiographic measurements were made of the anteroposterior diameters of the spinal canal and vertebral bodies from C3–6, and the presence of kyphosis were assessed. Lamina closure was defined as ≥ 10% decrease in the canal-to-body ratio at the final follow-up compared with that immediately after surgery at ≥ 1 vertebral level. The impact of lamina closure on neck pain, patient satisfaction, Japanese Orthopaedic Association scores, and recovery rates were also evaluated.

Results

The mean canal-to-body ratio at C3–6 was 0.69–0.72 preoperatively, 1.25–1.28 immediately after surgery, and 1.18–1.24 at the final follow-up examination. Lamina closure was observed in 34% of patients and was not associated with sex, age, or cause of myelopathy, but was significantly associated with the presence of preoperative kyphosis (p = 0.014). Between patients with and without lamina closure, there was no significant difference in preoperative (9.7 ± 3.1 vs 10.6 ± 2.5) and postoperative (13.7 ± 2.4 vs 13.1 ± 2.7) Japanese Orthopaedic Association scores, recovery rates (53.9 ± 29.9% vs 44.3 ± 29.5%), neck pain scores (3.5 ± 0.7 vs 3.3 ± 1.0), or patient satisfaction level (4.0 ± 1.4 vs 4.8 ± 1.0).

Conclusions

Lamina closure at ≥ 1 vertebral level occurred in 34% of patients. Although patients with lamina closure obtained equivalent recovery from myelopathy in a short-term follow-up, they tended to be less satisfied with surgery compared with those who did not have closure. The only significant risk factor identified was the presence of preoperative cervical kyphosis, and preventative methods for lamina closure, therefore, should be considered for patients with preoperative kyphosis.
Surgeon and patient radiation exposure in minimally invasive transforaminal lumbar interbody fusion
Authors: Bindal Rajesh K. , Glaze Sharon , Ognoskie Meghann , Tunner Van , Malone Robert , Ghosh Subrata
Published: November 2008

Object

Minimally invasive transforaminal lumbar interbody fusion (TLIF) is an increasingly popular procedure. The technique involves use of fluoroscopy to assist with pedicle screw (PS) placement. The potential exists for both the surgeon and the patient to become exposed to significant amounts of radiation. The authors undertook this study to quantify the radiation dose to the surgeon and patient during minimally invasive TLIF.

Methods

The authors undertook a prospective study of 24 consecutive patients who underwent minimally invasive TLIF. All surgeries were performed by the senior author (R.K.B.), who used techniques previously described. The surgeon wore a radiation monitor under an apron-style lead shield at waist level, at an unshielded collar location, and as a sterile ring badge containing a thermoluminescent dosimeter on the dominant (right) hand ring finger. Dosimeter readings were obtained for each case. A total of 33 spinal levels were treated in 24 patients. All treated levels were between L3–4 and L5–S1. In all cases of 1-level disease, 4 PSs were placed, and in all cases of 2-level disease, 6 screws were placed.

Results

. Mean fluoroscopy time was 1.69 minutes per case (range 3.73–0.82 minutes). Mean exposure per case to the surgeon on his dominant hand was 76 mRem, at the waist under a lead apron was 27 mRem, and at an unprotected thyroid level was 32 mRem. Mean exposure to the patient's skin was 59.5 mGy (range 8.3–252 mGy) in the posteroanterior plane and 78.8 mGy (range 6.3–269.5 mGy) in the lateral plane.

Conclusions

To the authors' knowledge, this is the first study of radiation exposure to the surgeon or patient in minimally invasive TLIF. Patient exposures were low and compare favorably with exposures involving other common interventional fluoroscopically guided procedures. Surgeon exposures are limited but require careful monitoring. Annual dose limits could be exceeded if a large number of these and other fluoroscopically guided procedures were performed.
Traumatic lateral spondylolisthesis of the lumbar spine with a unilateral locked facet: description of an unusual injury, probable mechanism, and management
Authors: Reddy Sangala Jaypal , Al-Holou Wajd N. , Leveque Jean-Christophe , La Marca Frank , Park Paul
Published: November 2008

Primary traumatic facet dislocations are unusual in the lumbar spine. Most occurrences have been reported at the lumbosacral junction associated with anterior subluxation. The authors describe 2 cases in which a high impact trauma resulted in lateral subluxation with a unilateral locked facet involving the lumbar spine. In their review of the literature, the authors found no previously reported cases of this type of injury. Both cases described in this report involved significant spinal stenosis, neurological injury, and spinal instability. A posterior surgical approach, with at least partial resection of the locked facet joint in conjunction with pedicle screw fixation, allowed successful reduction and stabilization of the injury.
The preservation of methanesulphonic acid in frozen ice-core samples
Authors: Abram Nerilie J. , Curran Mark A.J. , Mulvaney Robert , Vance Tessa
Published: November 2008

Ice-core records of methanesulphonic acid (MSA) provide a potentially powerful tool for producing proxy records of sea ice, a critical but poorly understood component of the Earth’s climate system. However, MSA is able to diffuse through solid ice, and here we examine the effect of two different methods of frozen storage on the preservation of MSA in archived ice-core samples. Re-analysis of archived ice sticks confirms that MSA diffuses out of ice cores archived in this manner. Despite MSA losses of up to 39% after 7 years storage, the ice sticks studied here preserve much of the variability of the original MSA record, suggesting that useful proxy records can be obtained from archived ice sticks. Furthermore, re-analysis of ice-core samples that had been refrozen into discrete bottled samples for storage demonstrates that it is possible to archive ice samples in a way that prevents MSA loss. In this case, accurate records of MSA variability and concentration were preserved even over storage periods of 15 years. This has important implications for the storage of ice cores and subsequent determination of MSA, and demonstrates that ice storage history needs to be considered when interpreting MSA records.
Sensitivity Modeling Study for an Ozone Occurrence during the 1996 Paso Del Norte Ozone Campaign
Authors: Lu Duanjun , Reddy Remata S. , Fitzgerald Rosa , Stockwell William R. , Williams Quinton L. , Tchounwou Paul B.
Published: November 2008

Surface ozone pollution has been a persistent environmental problem in the US and Europe as well as the developing countries. A key prerequisite to find effective alternatives to meeting an ozone air quality standard is to understand the importance of local anthropogenic emissions, the significance of biogenic emissions, and the contribution of long-range transport. In this study, an air quality modeling system that includes chemistry and transport, CMAQ, an emission processing model, SMOKE, and a mesoscale numerical meteorological model, WRF, has been applied to investigate an ozone event occurring during the period of the 1996 Paso del Norte Ozone Campaign. The results show that the modeling system exhibits the capability to simulate this high ozone occurrence by providing a comparable temporal variation of surface ozone concentration at one station and to capture the spatial evolution of the event. Several sensitivity tests were also conducted to identify the contributions to high surface ozone concentration from eight VOC subspecies, biogenic VOCs, anthropogenic VOCs and long-range transportation of ozone and its precursors. It is found that the reductions of ETH, ISOP, PAR, OLE and FORM help to mitigate the surface ozone concentration, and like anthropogenic VOCs, biogenic VOC plays a nonnegligible role in ozone formation. But for this case, long-range transport of ozone and its precursors appears to produce an insignificant contribution.
Cytotoxic Steroidal Saponins from the Flowers of Allium leucanthum
Authors: Mskhiladze Lasha , Legault Jean , Lavoie Serge , Mshvildadze Vakhtang , Kuchukhidze Jumber , Elias Riad , Pichette André
Published: November 2008

Allium leucanthum C. Koch is an endemic Caucasian species that grows in Georgia. The flowers are used in traditional medicine. Phytochemical investigation allowed the isolation of seven spirostanol type saponins from the flowers. Their structures were elucidated on the base of NMR and HRESIMS spectrometry data. A new compound, which we have named leucospiroside A (5), has been identified as (25R)-5α-spirostane-2α,3β,6β-triol 3-O-β-glucopyranosyl-(1→3)-β-glucopyranosyl-(1→2)-[β-glucopyranosyl-(1→3)]-β-glucopyranosyl-(1→4)-β-galactopyranoside. The six others were known substances, but are described in this plant for the first time. The crude extract, spirostanol and furostanol fractions, as well as isolated compounds, were evaluated for their in vitro cytotoxic activity. Compounds 1-3 and 5 were found to be the most active, with relatively similar IC50 values ranging from 3.7 to 5.8 μM for a lung cancer cell line (A549) and 5.6 to 8.2 μM for a colon cancer cell line (DLD-1).
Cognitive‐Performance Recovery of Alzheimer's Disease Model Mice by Modulation of Early Soluble Amyloidal Assemblies
Authors: Frydman‐Marom Anat , Rechter Meirav , Shefler Irit , Bram Yaron , Shalev Deborah E. , Gazit Ehud
Published: November 2008

Ein gezielt entworfener Oligomerisierungshemmer wechselwirkt mit frühen intermediären Aβ‐Aggregaten (Aβ=Amyloid‐β‐Polypeptid) und inhibiert so die Bildung der toxischen Oligomere, die die Alzheimer‐Krankheit verursachen. Das Bild zeigt das elektrostatische Potential der niederenergetischen Konformation des Dipeptid‐Inhibitors im Komplex mit Aβ.

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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

Ausgehend vom (−)‐Hajos‐Parrish‐Keton gelang eine hoch diastereoselektive Synthese des ABC‐Ringsystems von (−)‐Norzoanthamin (siehe Schema). Die drei quartären Kohlenstoffstereozentren am C‐Ring wurden durch eine 1,4‐Addition eingeführt, und eine intramolekulare Diels‐Alder‐Reaktion erzeugte das trans‐Decalin‐Gerüst für das AB‐Ringsystem.

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Cognitive‐Performance Recovery of Alzheimer's Disease Model Mice by Modulation of Early Soluble Amyloidal Assemblies
Authors: Frydman‐Marom Anat , Rechter Meirav , Shefler Irit , Bram Yaron , Shalev Deborah E. , Gazit Ehud
Published: November 2008

A rationally designed oligomerization inhibitor interacts with early intermediate assemblies of amyloid‐β polypeptide (Aβ) through the aromatic elements and inhibits their assembly into the toxic oligomers that cause Alzheimer's disease by a unique Cα‐methylation β‐breakage strategy. The electrostatic potential of the low‐energy conformation of the dipeptide inhibitor bound to Aβ is shown.

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Incidence and risk factors of prosthetic joint infection after total hip or knee replacement in patients with rheumatoid arthritis
Authors: Bongartz Tim , Halligan Christine S. , Osmon Douglas R. , Reinalda Megan S. , Bamlet William R. , Crowson Cynthia S. , Hanssen Arlen D. , Matteson Eric L.
Published: November 2008

Objective

Prosthetic joint infection is one of the most dreaded complications after total joint arthroplasty, a common procedure in patients with rheumatoid arthritis (RA). We conducted a study to evaluate potential risk factors of prosthetic joint infection and to clarify if RA is an independent predictor of this complication.

Methods

This study included all patients with RA who underwent total hip or knee replacement at the Mayo Clinic Rochester between January 1996 and June 2004. The association of potential risk factors with prosthetic joint infection was examined using Cox models. A matched cohort of patients with osteoarthritis (OA) was assembled to determine whether RA is an independent risk factor for prosthetic joint infection.

Results

We identified 462 patients with RA who underwent a total of 657 hip or knee replacements. Overall, 23 (3.7%) joint arthroplasties were complicated by an infection during a mean ± SD followup of 4.3 ± 2.4 years. Revision arthroplasty (hazard ratio [HR] 2.99, 95% confidence interval [95% CI] 1.02–8.75) and a previous prosthetic joint infection of the replaced joint (HR 5.49, 95% CI 1.87–16.14) were significant predictors of postoperative prosthetic joint infection. Comparison of RA patients with a matched cohort of OA patients identified an increased risk of prosthetic joint infections (HR 4.08, 95% CI 1.35–12.33) in patients with RA.

Conclusion

Patients with RA who undergo total hip or knee replacement are at increased risk of prosthetic joint infection, which is further increased in the setting of revision arthroplasty and a previous prosthetic joint infection. These findings highlight the importance of perioperative prophylactic measures and vigilance during the postoperative period.
Risk of cardiovascular mortality in patients with rheumatoid arthritis: A meta‐analysis of observational studies
Authors: Aviña‐Zubieta J. Antonio , Choi Hyon K. , Sadatsafavi Mohsen , Etminan Mahyar , Esdaile John M. , Lacaille Diane
Published: November 2008

Objective

To determine the magnitude of risk of cardiovascular mortality in patients with rheumatoid arthritis (RA) compared with the general population through a meta‐analysis of observational studies.

Methods

We searched Medline, EMBase, and Lilacs databases from their inception to July 2005. Observational studies that met the following criteria were assessed by 2 researchers: 1) prespecified RA definition, 2) clearly defined cardiovascular disease (CVD) outcome, including ischemic heart disease (IHD) and cerebrovascular accidents (CVAs), and 3) reported standardized mortality ratios (SMRs) and 95% confidence intervals (95% CIs). We calculated weighted–pooled summary estimates of SMRs (meta‐SMRs) for CVD, IHD, and CVAs using the random‐effects model, and tested for heterogeneity using the I2 statistic.

Results

Twenty‐four studies met the inclusion criteria, comprising 111,758 patients with 22,927 cardiovascular events. Overall, there was a 50% increased risk of CVD death in patients with RA (meta‐SMR 1.50, 95% CI 1.39–1.61). Mortality risks for IHD and CVA were increased by 59% and 52%, respectively (meta‐SMR 1.59, 95% CI 1.46–1.73 and meta‐SMR 1.52, 95% CI 1.40–1.67, respectively). We identified asymmetry in the funnel plot (Egger's test P = 0.002), as well as significant heterogeneity in all main analyses (P < 0.0001). Subgroup analyses showed that inception cohort studies (n = 4, comprising 2,175 RA cases) were the only group that did not show a significantly increased risk for CVD (meta‐SMR 1.19, 95% CI 0.86–1.68).

Conclusion

Published data indicate that CVD mortality is increased by ∼50% in RA patients compared with the general population. However, we found that study characteristics may influence the estimate.
Short‐term improvement of endothelial function in rituximab‐treated rheumatoid arthritis patients refractory to tumor necrosis factor α blocker therapy
Authors: Gonzalez‐Juanatey Carlos , Llorca Javier , Vazquez‐Rodriguez Tomas R. , Diaz‐Varela Nicolas , Garcia‐Quiroga Hermitas , Gonzalez‐Gay Miguel A.
Published: November 2008

Objective

Cardiovascular disease is the major cause of excessive mortality in rheumatoid arthritis (RA) and endothelial dysfunction plays a key role in atherosclerosis. The aim of the present study was to assess whether rituximab therapy was able to improve endothelial function in RA patients refractory to tumor necrosis factor α (TNFα) blockers.

Methods

Six consecutive RA patients (5 women; age range 55–79 years) with active disease refractory to TNFα inhibitor therapy were studied. Patients received intravenous rituximab (1 course, consisting of 2 infusions of 1,000 mg each separated by 2 weeks). Flow‐mediated endothelium‐dependent vasodilatation (FMD%) and endothelium‐independent vasodilatation (postnitroglycerin) were measured at day 0 prior to the first rituximab infusion, at week 2 (before the second infusion), and at month 6.

Results

At week 2, a dramatic increase in FMD% values was observed in all patients (mean ± SD 7.02 ± 2.31%, median 7.29%, range 3.2–9.75%) compared with those observed before the first infusion (mean ± SD 3.35 ± 1.58%, median 3.04%, range 1.69–5.89%). In addition, at month 6, FMD% values in all patients (mean ± SD 7.66 ± 1.73%, median 7.64%, range 5.61–9.98%) were greater than those found before the first infusion (P = 0.03). The dramatic improvement of FMD% was associated with a significant decrease in C‐reactive protein level and Disease Activity Score in 28 joints.

Conclusion

Our study demonstrates an active effect of rituximab on endothelial function in RA patients refractory to TNFα blockers.
Brain transport of neurotoxin‐I with PLA nanoparticles through intranasal administration in rats: a microdialysis study
Authors: Cheng Qiaoyuan , Feng Jian , Chen Jianming , Zhu Xuan , Li Fanzhu
Published: November 2008

The purpose of this study was to encapsulate neurotoxin‐I (NT‐I) within polylactic acid (PLA) nanoparticles (NPs) and to evaluate their transport into the brain after intranasal administration (i.n.) using a microdialysis sampling technique. NT‐I‐NPs (NT‐I radiolabeled with sodium [125I]iodide) were prepared and characterized. Then, NT‐I‐NPs were administered i.n. or i.v. to rats and the radioactivities in the olfactory bulbs were monitored for up to 240 min. The nanoparticles prepared were spherical with a homogenous size distribution. The mean particle size, zeta potential and entrapment efficiency were −28.6±2.3 mV, 65 nm and 35.5±2.8%, respectively. The brain transport results showed that the time to reach the peak level (Tmax) of NT‐I‐NPs (i.n.) was 65 min, shorter than NT‐I‐NPs (i.v.) (95 min) or NT‐I (i.v.) (145 min). The concentration at peak level (Cmax) and the total area under the concentration–time curves from zero to 4 h (AUC0–4 h) of each group followed the following order: NT‐I‐NPs (i.n.)>NT‐I‐NPs (i.v.)>NT‐I (i.v.). The corresponding absolute bioavailabilities (Fabs) of NT‐I‐NPs (i.n.) were about 160%, 196% with NT‐I‐NPs (i.v.) and NT‐I (i.v.) as reference preparations, respectively. The brain delivery of NT‐I could be enhanced with PLA nanoparticles either through i.n. or i.v. administration. Furthermore, the enhancement was more significant for i.n. than for i.v. administration. Nanoparticles as carriers would be a potential way to improve the brain transport for centrally active peptides. Copyright © 2008 John Wiley & Sons, Ltd.
The Biochemistry of Drug Metabolism – An Introduction
Authors: Testa Bernard , Krämer Stefanie D.
Published: November 2008

This review continues a general presentation of the metabolism of drugs and other xenobiotics begun in three recent issues ofChemistry & Biodiversity.The presentPartis dedicated to reactions of conjugation, namely methylation, sulfonation, and phosphorylation, glucuronidation and other glycosidations, acetylation and other acylations, the formation and fate of coenzyme A conjugates, glutathione conjugation, and the reaction of amines with carbonyl compounds. It presents the many transferases involved, their nomenclature, relevant biochemical properties, catalytic mechanisms, and the reactions they catalyze. Nonenzymatic reactions, mainly of glutathione conjugation, also receive due attention. A number of medicinally, environmentally, and toxicologically relevant examples are presented and discussed.
Tetrathiafulvalene Porphyrins
Authors: Nielsen Kent A. , Levillain Eric , Lynch Vincent M. , Sessler Jonathan L. , Jeppesen Jan O.
Published: November 2008

Four tetrathiafulvalene (TTF)‐annulated porphyrins 1–4 were synthesized and characterized. All contain a tetraphenylporphyrin (TPP) core onto which four, two, or one TTF subunits were annulated. Absorption and fluorescence spectroscopic studies together with electrochemical investigations reveal that interactions between the porphyrin system and the annulated TTF units take place in solution. The annulation of one or more TTF units to the porphyrin core has a profound effect on the reduction potentials associated with this latter framework, with positive shifts in the range of 0.105 to 0.355 V and 0.200 to 0.370 V for the first and second reduction potential, respectively, compared to the corresponding processes in the model compound TPP, 18. The redox potentials for the first oxidation of the TTF units are considerably shifted in 4 (ΔEox1=+0.285 V) and 2 (ΔEox1=−0.140 V), whereas for 1 and 3 these potentials remain within the region expected for a normal TTF unit. Considerable changes in the second oxidation potential associated with the TTF subunits were seen for 2 (ΔEox1=−0.085) and 3 (ΔEox1=−0.175). The emission spectra of 1–4 revealed that the porphyrin fluorescence is almost quenched in the neutral state of the TTF‐annulated porphyrins, a finding that is consistent with substantial electron transfer taking place from the TTF subunits to the porphyrin core. Oxidation of the TTF unit(s) (TTF→TTF.+) present in 1–4 leads to the emission intensity being restored.
Which Properties of a Spanning Network of Hydration Water Enable Biological Functions?
Authors: Brovchenko Ivan , Oleinikova Alla
Published: November 2008

The central role of water in biological functions is well‐recognized, but numerous questions concerning the physical mechanisms behind the importance of water for life remain unanswered. Water in biosystems exists mainly as hydration water. Analysis of the phase diagram of hydration water shows that biological functions are possible only when the surfaces of biomolecules are covered by spanning hydrogen‐bonded networks of hydration water. The comparative studies of the various properties of hydrated biosystems in the presence and in the absence of a spanning water network should clarify its specific physical properties, which are crucial for biological functions. Herein, we summarize the recent progress in these studies. The biological activity of the living organisms is maximal in a narrow temperature interval, where the spanning network of hydration water breaks up with heating via a percolation transition. The entropy of the hydration water related to the diversity of cluster size diverges at this percolation threshold. The possible role of this phenomenon in life processes is discussed.
Relating streamflow characteristics to specialized insectivores in the Tennessee River Valley: a regional approach
Authors: Knight Rodney R. , Brian Gregory M. , Wales Amy K.
Published: November 2008

Analysis of hydrologic time series and fish community data across the Tennessee River Valley identified three hydrologic metrics essential to habitat suitability and food availability for insectivorous fish communities in streams of the Tennessee River Valley: constancy (flow stability or temporal invariance), frequency of moderate flooding (frequency of habitat disturbance), and rate of streamflow recession. Initial datasets included 1100 fish community sites and 300 streamgages. Reduction of these datasets to sites with coexisting data yielded 33 sites with streamflow and fish community data for analysis. Identification of critical hydrologic metrics was completed using a multivariate correlation procedure that maximizes the rank correlation between the hydrologic metrics and fish community resemblance matrices. Quantile regression was used to define thresholds of potential ranges of insectivore scores for given values of the hydrologic metrics. Increased values of constancy and insectivore scores were positively correlated. Constancy of streamflow maintains wetted perimeter, which is important for providing habitat for fish spawning and increased surface area for invertebrate colonization and reproduction. Site scores for insectivorous fish increased as the frequency of moderate flooding (3 times the median annual streamflow) decreased, suggesting that insectivorous fish communities respond positively to less frequent disturbance and a more stable habitat. Increased streamflow recession rates were associated with decreased insectivore scores. Increased streamflow recession can strand fish in pools and other areas that are disconnected from flowing water and remove invertebrates as food sources that were suspended during high‐streamflow events. Copyright © 2008 John Wiley & Sons, Ltd.
A dam problem: simulated upstream impacts for a Searsville‐like watershed
Authors: Heppner Christopher S. , Loague Keith
Published: November 2008

The integrated hydrology model (InHM), a physics‐based hydrologic‐response model with sediment‐transport capabilities, was used to simulate upstream impacts from dam construction/removal for a generalized approximation of the Searsville watershed in Portola Valley, California. Four 10‐year simulation scenarios (pre‐dam, early dam, current and post‐dam) were considered. Each scenario was simulated using the same sequence of synthetically generated rainfall and evapotranspiration. For each scenario the boundary‐value problem was constructed based on the available watershed information (e.g. topography, soils, geology, reservoir bathymetry and land use). The results from the simulations are presented in terms of the temporal and spatial characteristics of hydrologic response and sediment transport. The commonalities/differences between the four Searsville‐like watershed scenarios are discussed. The effort demonstrates that heuristic physics‐based simulation can be a useful tool for the characterization of dam‐related impacts at the watershed scale. Copyright © 2008 John Wiley & Sons, Ltd.
Rapid determination of sterols in vegetable oils by CEC using methacrylate ester‐based monolithic columns
Authors: Lerma‐García María Jesús , Simó‐Alfonso Ernesto F. , Ramis‐Ramos Guillermo , Herrero‐Martínez José M.
Published: November 2008

A method for the determination of sterols in vegetable oils by CEC with UV–Vis detection, using methacrylate ester‐based monolithic columns, has been developed. To prepare the columns, polymerization mixtures containing monomers of different hydrophobicities were tried. The influence of composition of polymerization mixture was optimized in terms of porogenic solvent, monomers/porogens and monomer/crosslinker ratios. The composition of the mobile phase was also studied. The optimum monolith was obtained with lauryl methacrylate monomer at 60:40% (wt:wt) lauryl methacrylate/ethylene dimethacrylate ratio and 60 wt% porogens with 20 wt% of 1,4‐butanediol (12 wt% 1,4‐butanediol in the polymerization mixture). Excellent resolution between sterols was achieved in less than 7 min with an 85:10:5 v/v/v ACN–2‐propanol–water buffer containing 5 mM Tris at pH 8.0. The limits of detection were lower than 0.04 mM, and inter‐day and column‐to‐column reproducibilities at 0.75 mM were better than 6.2%. The method was applied to the determination of sterols in vegetable oils with different botanical origins and to detect olive oil adulteration with sunflower and soybean oils.