bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural similarity of loops in protein families: toward the understanding of protein evolution
Authors: Panchenko Anna R , Madej Thomas
Published: February 2005

Background

Protein evolution and protein classification are usually inferred by comparing protein cores in their conserved aligned parts. Structurally aligned protein regions are separated by less conserved loop regions, where sequence and structure locally deviate from each other and do not superimpose well.

Results

Our results indicate that even longer protein loops can not be viewed as "random coils" and for the majority of protein families in our test set there exists a linear correlation between the measures of sequence similarity and loop structural similarity. Results suggest that distance matrices derived from the loop (dis)similarity measure may produce in some cases more reliable cluster trees compared to the distance matrices based on the conventional measures of sequence and structural (dis)similarity.

Conclusions

We show that by considering "dissimilar" loop regions rather than only conserved core regions it is possible to improve our understanding of protein evolution.
Phenotypic error threshold; additivity and epistasis in RNA evolution
Authors: Takeuchi Nobuto , Poorthuis Petrus H , Hogeweg Paulien
Published: February 2005

Background

The error threshold puts a limit on the amount of information maintainable in Darwinian evolution. The error threshold was first formulated in terms of genotypes. However, if a genotype-phenotype map involves redundancy ("mutational neutrality"), the error threshold should be formulated in terms of phenotypes since there is no unique fittest genotype. A previous study formulated the error threshold in terms of phenotypes, and their results showed that a rather low degree of mutational neutrality can increase the error threshold unlimitedly.

Results

We obtain an analytical formulation of the phenotypic error threshold by considering the "additive assumption", in which base substitutions do not influence each other (no epistasis). Our formulation shows that an increase of the error threshold due to mutational neutrality is limited. Computer simulations of RNA evolution are conducted to verify our formulation, and the results show a good agreement between the analytical prediction and the simulations. The comparison with the previous formulation illustrates that it is important for the prediction of the error threshold to consider that the number of base substitutions per replication is rather large near the error threshold. To examine the additive assumption, a detailed analysis of additivity and epistasis in RNA folding of a particular sequence is performed. The results show a high degree of epistasis in RNA folding; furthermore, the analysis also elucidates the reason of the success of the additive assumption.

Conclusions

We conclude that an increase of the error threshold by mutational neutrality is limited, and that the additive assumption achieves a good prediction of the error threshold in spite of a high degree of epistasis in RNA folding because the average number of base substitutions of sequences retaining the phenotype per replication is sufficiently small to avoid of the effect of epistasis.
Herpesvirus pan encodes a functional homologue of BHRF1, the Epstein-Barr virus v-Bcl-2
Authors: Howell Melanie , Williams Tracey , Hazlewood Sheila A
Published: February 2005

Background

Epstein-Barr virus (EBV) latently infects about 90% of the human population and is associated with benign and malignant diseases of lymphoid and epithelial origin. BHRF1, an early lytic cycle antigen, is an apoptosis suppressing member of the Bcl-2 family. In vitro studies imply that BHRF1 is dispensable for both virus replication and transformation. However, the fact that BHRF1 is highly conserved not only in all EBV isolates studied to date but also in the analogous viruses Herpesvirus papio and Herpesvirus pan that infect baboons and chimpanzees respectively, suggests BHRF1 may play an important role in vivo.

Results

Herpesvirus papio BHRF1 has been shown to function in an analogous manner to EBV BHRF1 in response to DNA damaging agents in human keratinocytes. In this study we show that the heterologous expression of the previously uncharacterised Herpesvirus pan BHRF1 in the human Burkitt's lymphoma cell line Ramos-BL provides similar anti-apoptotic functions to that of EBV BHRF1 in response to apoptosis triggered by serum withdrawal, etoposide treatment and ultraviolet (UV) radiation. We also map the amino acid changes onto the recently solved structure of the EBV BHRF1 and reveal that these changes are unlikely to alter the 3D structure of the protein.

Conclusions

These findings show that the functional conservation of BHRF1 extends to a lymphoid background, suggesting that the primate virus proteins interact with cellular proteins that are themselves highly conserved across the higher primates. Further weight is added to this suggestion when we show that the difference in amino acid sequences map to regions on the 3D structure of EBV BHRF1 that are unlikely to change the conformation of the protein.
Proteolytic cleavage of pertussis toxin S1 subunit is not essential for its activity in mammalian cells
Authors: Carbonetti Nicholas H , Mays R Michael , Artamonova Galina V , Plaut Roger D , Worthington Zoë EV
Published: February 2005

Background

Pertussis toxin (PT) is an exotoxin virulence factor produced by Bordetella pertussis, the causative agent of whooping cough. PT consists of an active subunit (S1) that ADP-ribosylates the alpha subunit of several mammalian G proteins, and a B oligomer (S2–S5) that binds glycoconjugate receptors on cells. PT appears to enter cells by endocytosis, and retrograde transport through the Golgi apparatus may be important for its cytotoxicity. A previous study demonstrated that proteolytic processing of S1 occurs after PT enters mammalian cells. We sought to determine whether this proteolytic processing of S1 is necessary for PT cytotoxicity.

Results

Protease inhibitor studies suggested that S1 processing may involve a metalloprotease, and processing does not involve furin, a mammalian cell protease that cleaves several other bacterial toxins. However, inhibitor studies showed a general lack of correlation of S1 processing with PT cellular activity. A combination of replacement, insertion and deletion mutations in the C-terminal region of S1, as well as mass spectrometry data, suggested that the cleavage site is located around residue 203–204, but that cleavage is not strongly sequence-dependent. Processing of S1 was abolished by each of 3 overlapping 8 residue deletions just downstream of the putative cleavage site, but not by smaller deletions in the same region. Processing of the various mutant forms of PT did not correlate with cellular activity of the toxin, nor with the ability of the bacteria producing them to infect the mouse respiratory tract. In addition, S1 processing was not detected in transfected cells expressing S1, even though S1 was fully active in these cells.

Conclusions

S1 processing is not essential for the cellular activity of PT. This distinguishes it from the processing of various other bacterial toxins, which has been shown to be important for their cytotoxicity. S1 processing may be mediated primarily by a metalloprotease, but the cleavage site on S1 is not sequence-dependent and processing appears to depend on the general topology of the protein in that region, indicating that multiple proteases may contribute to this cleavage.
Role of Leishmania (Leishmania) chagasi amastigote cysteine protease in intracellular parasite survival: studies by gene disruption and antisense mRNA inhibition
Authors: Mundodi Vasanthakrishna , Kucknoor Ashwini S , Gedamu Lashitew
Published: February 2005

Background

The parasitic protozoa belonging to Leishmania (L.) donovani complex possess abundant, developmentally regulated cathepsin L-like cysteine proteases. Previously, we have reported the isolation of cysteine protease gene, Ldccys2 from Leishmania (L.) chagasi. Here, we have further characterized this cysteine protease gene and demonstrated its role during infection and survival of Leishmania (L.) chagasi within the U937 macrophage cells.

Results

The amastigote specific Ldccys2 genes of L. (L.) chagasi and L. (L.) donovani have identical gene organization, as determined by southern blots. In vivo expression analyses by Northern blots showed that Ldccys2 is amastigote specific. Western blot using anti-Ldccys2 antibody confirmed the amastigote specific protein expression. Recombinant expression of Ldccys2, a 30 kDA protein, was functionally active in a gelatin assay. Results from Ldccys2 heterozygous knockout mutants showed its role during macrophage infection and in intra-macrophage survival of the parasites. Since attempts to generate null mutants failed, we used antisense RNA inhibition to regulate Ldcccys2 gene expression. Not surprisingly, the results from antisense studies further confirmed the results from heterozygous knockout mutants, reiterating the importance of amastigote specific cysteine proteases in Leishmania infection and pathogenesis.

Conclusions

The study shows that Ldccys2 is a developmentally regulated gene and that Ldccys2 is expressed only in infectious amastigote stages of the parasite. The collective results from both the heterozygous knockout mutants and antisense mRNA inhibition studies shows that Ldccys2 helps in infection and survival of L. (L.) chagasi amastigotes within the macrophage cells. Finally, antisense RNA technique can be used as an alternate approach to gene knockout, for silencing gene expression in L. (L.) chagasi, especially in cases such as this, where a null mutant cannot be achieved by homologous recombination.
Nucleus accumbens core lesions retard instrumental learning and performance with delayed reinforcement in the rat
Authors: Cardinal Rudolf N , Cheung Timothy HC
Published: February 2005

Background

Delays between actions and their outcomes severely hinder reinforcement learning systems, but little is known of the neural mechanism by which animals overcome this problem and bridge such delays. The nucleus accumbens core (AcbC), part of the ventral striatum, is required for normal preference for a large, delayed reward over a small, immediate reward (self-controlled choice) in rats, but the reason for this is unclear. We investigated the role of the AcbC in learning a free-operant instrumental response using delayed reinforcement, performance of a previously-learned response for delayed reinforcement, and assessment of the relative magnitudes of two different rewards.

Results

Groups of rats with excitotoxic or sham lesions of the AcbC acquired an instrumental response with different delays (0, 10, or 20 s) between the lever-press response and reinforcer delivery. A second (inactive) lever was also present, but responding on it was never reinforced. As expected, the delays retarded learning in normal rats. AcbC lesions did not hinder learning in the absence of delays, but AcbC-lesioned rats were impaired in learning when there was a delay, relative to sham-operated controls. All groups eventually acquired the response and discriminated the active lever from the inactive lever to some degree. Rats were subsequently trained to discriminate reinforcers of different magnitudes. AcbC-lesioned rats were more sensitive to differences in reinforcer magnitude than sham-operated controls, suggesting that the deficit in self-controlled choice previously observed in such rats was a consequence of reduced preference for delayed rewards relative to immediate rewards, not of reduced preference for large rewards relative to small rewards. AcbC lesions also impaired the performance of a previously-learned instrumental response in a delay-dependent fashion.

Conclusions

These results demonstrate that the AcbC contributes to instrumental learning and performance by bridging delays between subjects' actions and the ensuing outcomes that reinforce behaviour.
Differences in need for antihypertensive drugs among those aware and unaware of their hypertensive status: a cross sectional survey
Authors: Khan Nadia A , Wardman Dennis , Campbell Norman RC
Published: February 2005

Background

Lack of antihypertensive use among hypertensive individuals is a major public health problem. It remains unclear as to how much of this lack of treatment is because of failure to diagnose hypertension or failure to initiate drug treatment for those with a diagnosis of hypertension. The primary aim of this study was to determine the proportion of those untreated individuals who would be recommended to start drug therapy for control of blood pressure among those aware or unaware of their diagnosis of hypertension.

Methods

The Canadian Heart Health Surveys (1986 – 1992), a national, cross-sectional descriptive survey (n = 23 129), was used to determine the proportion of individuals who were untreated, yet satisfied the 2004 Canadian hypertension guidelines for initiating drug therapy. Patients were divided into subgroups of those aware and unaware of having a diagnosis of hypertension according to self reported awareness from the survey.

Results

Of those with untreated hypertension (= 140/90 mmHg), only 37% were aware of their diagnosis. 74% of untreated individuals aware of their diagnosis of hypertension would require drug therapy, compared to 57% of those who were unaware. Of those >65 years of age, 52% of aware individuals needed drug therapy whereas only 34% of unaware elderly would need drug treatment.

Conclusion

In both unaware and aware subgroups, the majority of patients with untreated hypertension would benefit from antihypertensive drug therapy according to the 2004 Canadian Hypertension recommendations. The proportion of untreated patients that still need drug therapy was higher among those who were aware compared to those who were unaware. This finding suggests that the major gap in hypertension control may be in initiating drug therapy rather than in diagnosing hypertension. Further studies are needed to confirm these results to ultimately help strategize public health efforts in controlling hypertension.
International outbreak of SalmonellaOranienburg due to German chocolate
Authors: Werber Dirk , Dreesman Johannes , Feil Fabian , van Treeck Ulrich , Fell Gerhard , Ethelberg Steen , Hauri Anja M , Roggentin Peter , Prager Rita , Fisher Ian ST , Behnke Susanne C , Bartelt Edda , Weise Ekkehard , Ellis Andrea , Siitonen Anja , Andersson Yvonne , Tschäpe Helmut , Kramer Michael H , Ammon Andrea
Published: February 2005

Background

This report describes a large international chocolate-associated Salmonella outbreak originating from Germany.

Methods

We conducted epidemiologic investigations including a case-control study, and food safety investigations. Salmonella (S.) Oranienburg isolates were subtyped by the use of pulsed-field gel electrophoresis (PFGE).

Results

From 1 October 2001 through 24 March 2002, an estimated excess of 439 S. Oranienburg notifications was registered in Germany. Simultaneously, an increase in S. Oranienburg infections was noted in other European countries in the Enter-net surveillance network. In a multistate matched case-control study in Germany, daily consumption of chocolate (matched odds ratio [MOR]: 4.8; 95% confidence interval [CI]: 1.3–26.5), having shopped at a large chain of discount grocery stores (MOR: 4.2; CI: 1.2–23.0), and consumption of chocolate purchased there (MOR: 5.0; CI: 1.1–47.0) were associated with illness. Subsequently, two brands from the same company, one exclusively produced for that chain, tested positive for S. Oranienburg. In two other European countries and in Canada chocolate from company A was ascertained that also contained S. Oranienburg. Isolates from humans and from chocolates had indistinguishable PFGE profiles. No source or point of contamination was identified. Epidemiological identification of chocolate as a vehicle of infections required two months, and was facilitated by proxy measures.

Conclusions

Despite the use of improved production technologies, the chocolate industry continues to carry a small risk of manufacturing Salmonella-containing products. Particularly in diffuse outbreak-settings, clear associations with surrogates of exposure should suffice to trigger public health action. Networks such as Enter-net have become invaluable for facilitating rapid and appropriate management of international outbreaks.
Association between fetal growth restriction and polymorphisms at sites -1 and +3 of pituitary growth hormone: a case-control study
Authors: Adkins Ronald M , Campese Caroline , Vaidya Rehana , Boyd Theonia K
Published: February 2005

Background

Fetal growth restriction is associated with significantly increased risks of neonatal death and morbidity and with susceptibility to hypertension, cardiovascular disease and NIDDM later in life. Human birth weight has a substantial genetic component, with at least a quarter of the variation attributable to additive genetic effects.

Methods

One hundred twenty-five subjects (83 control and 42 case) were selected using stringent inclusion/exclusion criteria. DNA sequencing was used to identify 26 single nucleotide polymorphisms in the pituitary growth hormone gene (GH1) at which all subjects were genotyped. Association with fetal growth restriction was tested by logistic regression for all sites with minor allele frequencies greater than 5%.

Results

Logistic regression identified significant association with fetal growth restriction of C alleles at sites -1 and +3 (relative to the start of transcription) that are in complete linkage disequilibrium. These alleles are present at higher frequency (6% vs. 0.4%) in fetal growth restricted subjects and are associated with an average reduction in birth weight of 152 g in normal birth weight and 97 g in low birth weight subjects.

Conclusions

There is suggestive association between fetal growth restriction and the presence of C alleles at sites -1 and +3 of the pituitary growth hormone gene.
Psychometric properties and clinical utility of the Scale for Suicidal Ideation (SSI) in adolescents
Authors: Holi Matti M , Pelkonen Mirjami , Karlsson Linnea , Kiviruusu Olli , Ruuttu Titta , Heilä Hannele , Tuisku Virpi , Marttunen Mauri
Published: February 2005

Background

Accurate assessment of suicidality is of major importance in both clinical and research settings. The Scale for Suicidal Ideation (SSI) is a well-established clinician-rating scale but its suitability to adolescents has not been studied. The aim of this study was to evaluate the reliability and validity, and to test an appropriate cutoff threshold for the SSI in a depressed adolescent outpatient population and controls.

Methods

218 adolescent psychiatric outpatient clinic patients suffering from depressive disorders and 200 age- and sex-matched school-attending controls were evaluated by the SSI for presence and severity of suicidal ideation. Internal consistency, discriminative-, concurrent-, and construct validity as well as the screening properties of the SSI were evaluated.

Results

Cronbach's α for the whole SSI was 0.95. The SSI total score differentiated patients and controls, and increased statistically significantly in classes with increasing severity of suicidality derived from the suicidality items of the K-SADS-PL diagnostic interview. Varimax-rotated principal component analysis of the SSI items yielded three theoretically coherent factors suggesting construct validity. Area under the receiver operating characteristic (ROC) curve was 0.84 for the whole sample and 0.80 for the patient sample. The optimal cutoff threshold for the SSI total score was 3/4 yielding sensitivity of 75% and specificity of 88.9% in this population.

Conclusions

SSI appears to be a reliable and a valid measure of suicidal ideation for depressed adolescents.
Patient characteristics and clinical management of patients with shoulder pain in U.S. primary care settings: Secondary data analysis of the National Ambulatory Medical Care Survey
Authors: Wofford James L , Mansfield Richard J , Watkins Raquel S
Published: February 2005

Background

Although shoulder pain is a commonly encountered problem in primary care, there are few studies examining its presenting characteristics and clinical management in this setting.

Methods

We performed secondary data analysis of 692 office visits for shoulder pain collected through the National Ambulatory Medical Care Survey (Survey years 1993–2000). Information on demographic characteristics, history and place of injury, and clinical management (physician order of imaging, physiotherapy, and steroid intraarticular injection) were examined.

Results

Shoulder pain was associated with an injury in one third (33.2% (230/692)) of office visits in this population of US primary care physicians. Males, and younger adults (age ≤ 52) more often associated their shoulder pain with previous injury, but there were no racial differences in injury status. Injury-related shoulder pain was related to work in over one-fifth (21.3% (43/202)) of visits.

An x-ray was performed in 29.0% (164/566) of office visits, a finding that did not differ by gender, race, or by age status. Other imaging (CT scan, MRI, or ultrasound) was infrequently performed (6.5%, 37/566).

Physiotherapy was ordered in 23.9% (135/566) of visits for shoulder pain. Younger adults and patients with a history of injury more often had physiotherapy ordered, but there was no significant difference in the ordering of physiotherapy by gender or race. Examination of the use of intraarticular injection was not possible with this data set.

Conclusion

These data from the largest sample of patients with shoulder pain presenting to primary care settings offer insights into the presenting characteristics and clinical management of shoulder pain at the primary care level. The National Ambulatory Medical Care Survey is a useful resource for examining the clinical management of specific symptoms in U.S. primary care offices.
A novel surgical procedure for bridging of massive bone defects
Authors: Knothe Ulf R , Springfield Dempsey S
Published: February 2005

Background

Bony defects arising from tumor resection or debridement after infection, non-union or trauma present a challenging problem to orthopedic surgeons, as well as patients due to compliance issues. Current treatment options are time intensive, require more than one operation and are associated with high rate of complications. For this reason, we developed a new surgical procedure to bridge a massive long bone defect.

Methods

To bridge the gap, an in situ periosteal sleeve is elevated circumferentially off of healthy diaphyseal bone adjacent to the bone defect. Then, the adjacent bone is osteotomized and the transport segment is moved along an intramedullary nail, out of the periosteal sleeve and into the original diaphyseal defect, where it is docked. Vascularity is maintained through retention of the soft tissue attachments to the in situ periosteal sleeve. In addition, periosteal osteogenesis can be augmented through utilization of cancellous bone graft or in situ cortical bone adherent to the periosteal sleeve.

Results

The proposed procedure is novel in that it exploits the osteogenic potential of the periosteum by replacing the defect arising from resection of tissue out of a pathological area with a defect in a healthy area of tissue, through transport of the adjacent bone segment. Furthermore, the proposed procedure has several advantages over the current standard of care including ease of implementation, rapid patient mobilization, and no need for specialized implants (intramedullary nails are standard inventory for surgical oncology and trauma departments) or costly orthobiologics.

Conclusions

The proposed procedure offers a viable and potentially preferable alternative to the current standard treatment modalities, particularly in areas of the world where few surgeons are trained for procedures such as distraction osteogenesis (e.g. the Ilizarov procedure) as well as areas of the world where surgeons have little access to expensive, complex devices and orthobiologics.
TPO/Mpl Studies in Agnogenic Myeloid Metaplasia
Authors: Hemavathy Kirugaval C , Suppiah Kathir , Hashmi Gazala , Novetsky Allan D , Wang Jen C
Published: February 2005

Background

Agnogenic myeloid metaplasia (AMM) is one of the Philadelphia chromosome negative myeloproliferative disorder and is diagnosed by hyperplasia of atypical megakaryocytes, hepatosplenomegaly, extramedullary hematopoiesis and bone marrow fibrosis. Fibrosis is considered to be a secondary consequence of enhanced levels of fibrogenic growth factors such as TGF β1, bFGF and PDGF produced by enhanced numbers of megakaryocytes, while the primary cause is considered to be the enhanced proliferation of a defective stem cell. We have previously reported that thrombopoietin (TPO) is elevated in patients with AMM. Others have reported that Mpl protein is decreased in these patients. Since TPO is essential for the development of megakaryocytes, and Mpl protein is the receptor for TPO, we extended the study of TPO/Mpl to in vitro and in vivo cell culture systems to better understand the mechanism that leads to reduced Mpl protein in AMM patients.

Results

Plasma TPO levels were significantly elevated and Mpl protein levels were significantly reduced in AMM patients in concordance with previous studies. Platelet Mpl transcripts in AMM were however similar to those in controls. We also cloned Mpl cDNA from AMM patients and tested for their ability to make functional proteins in vitro and in the in vivo system of 293 T human embryonic kidney cells. Their expression including the glycosylated forms was similar to those from the controls. We also measured the level of translation initiation factor, eIF4E and found it to be increased in patients with AMM demonstrating that the reduced Mpl protein may not be due to translation defects.

Conclusions

Our studies using the in vitro and in vivo systems further confirm that reduced Mpl protein levels are not due to defects in its transcription/translation. Reduced Mpl protein could be due to its increased internalisation owing to enhanced plasma TPO or in vivo intrinsic defects in patients with AMM.
The Cut Flow Index: An Intraoperative Predictor of the Success of Extracranial-Intracranial Bypass for Occlusive Cerebrovascular Disease
Authors: Amin-Hanjani Sepideh , Du Xinjian , Mlinarevich Nada , Meglio Guido , Zhao Meide , Charbel Fady T.
Published: February 2005

OBJECTIVE:

There has been a resurgence of interest in selective extracranial-intracranial bypass for revascularization of cerebrovascular occlusive disease. We evaluated the usefulness of intraoperative blood flow measurements in predicting graft success after extracranial-intracranial bypass.

METHODS:

A retrospective review of 51 cases of extracranial-intracranial bypass for purposes of flow augmentation in the setting of cerebrovascular occlusive disease was performed. In all cases, free flow from the cut end of the donor vessel, termed cut flow, was measured. The cut flow index (CFI) (bypass flow [ml/min] / cut flow [ml/min]) was derived and correlated with bypass patency, postoperative bypass flow, cerebrovascular reserve testing, and clinical outcome.

RESULTS:

The CFI was a significant predictor of bypass patency (P = 0.002). Using a CFI of 0.5 as a threshold, the bypass patency rate was 92% in cases with a CFI greater than 0.5 compared with 50% in cases with a CFI less than 0.5. Intraoperative bypass flow correlated well with postoperative measurements obtained from quantitative phase-contrast magnetic resonance imaging. An analysis of cases with a poor CFI indicated that a logical interpretation of bypass function can be performed during surgery.

CONCLUSION:

A poor CFI can alert surgeons to potential difficulties with the donor vessel, anastomosis, or recipient vessel during surgery. Furthermore, a CFI closely approximating 1.0 provides physiological confirmation of impaired cerebrovascular reserve in the recipient bed.
Surgical Exposure of the Sciatic Nerve in the Gluteal Region: Anatomic and Historical Comparison of Two Approaches
Authors: Patil Parag G. , Friedman Allan H.
Published: February 2005

OBJECTIVE:

To increase awareness among neurosurgeons of alternative surgical approaches to lesions of the sciatic nerve in the gluteal region.

METHODS:

The dominant surgical approach to lesions of the proximal sciatic nerve involves detachment and medial reflection of the gluteus maximus through a question-mark incision. An alternative to this infragluteal exposure is a transgluteal approach, which provides access to the sciatic nerve by splitting the gluteus maximus through a curvilinear incision. We explored the anatomy and surgical history of these approaches through cadaveric study, our own case series, and a literature review.

RESULTS:

The infragluteal approach uses a larger incision, extensive dissection, and postoperative bracing while allowing wide exposure of the nerve inferiorly into the thigh. By contrast, the transgluteal approach minimizes dissection and spares muscle attachments but requires meticulous attention to hemostasis and provides a more focal exposure of the sciatic nerve. During the past century, the infragluteal approach has been described more frequently and has become increasingly popular among peripheral-nerve surgeons. For comparison, we present three patients in whom the transgluteal approach was used to treat substantial lesions of the proximal sciatic nerve.

CONCLUSION:

At the present time, the majority of peripheral nerve surgeons use an infragluteal approach to the proximal sciatic nerve. However, for select patients with well-defined and localized lesions, the transgluteal approach may provide sufficient nerve exposure with lowered operative complexity and postoperative morbidity.
Using Dermabond for Wound Closure in Lumbar and Cervical Neurosurgical Procedures
Authors: Hall Lance T. , Bailes Julian E.
Published: February 2005

OBJECTIVE:

2-Octylcyanoacrylate (Dermabond; Ethicon, Inc., Somerville, NJ) is a liquid adhesive being used with increasing frequency for the closure of lacerations and surgical incisions. Dermabond provides excellent cosmetic closure, and recent studies have demonstrated very low infection risks when it is properly applied. There are no published studies using Dermabond on lumbar or cervical procedures. This study was undertaken to determine whether Dermabond is safe and efficacious to use in these common neurosurgical procedures.

METHODS:

Records of 200 consecutive patients with Dermabond closure after anterior cervical discectomy, microlumbar discectomy, or lumbar laminectomy by the senior author (JEB) with a mean follow-up time of 5.42 months were retrospectively reviewed. Suspected infections with or without confirmatory cultures, erythema, and incisional drainage were documented.

RESULTS:

Of 200 patients, 85 underwent microlumbar discectomy, 22 lumbar laminectomy, and 93 anterior cervical discectomy. There was only 1 definitive infection, which was a culture-proven discitis in a microlumbar discectomy patient. Of the remaining 85 microlumbar discectomies, there was 1 transient incisional erythema. Of the 22 lumbar laminectomies, there was 1 patient with clinical superficial wound infection with negative cultures and 4 patients with transient incisional drainage without infection. Of the 93 anterior cervical discectomies, 2 had transient incisional drainage without infection.

CONCLUSION:

This study demonstrates that Dermabond is safe to use in neurosurgery patients undergoing lumbar or cervical procedures, with only 1 patient of 200 having a proven infection. Patients are able to shower and do not have sutures or staples to remove. Patient responses are overwhelmingly positive.
Pars Screw Fixation of a Hangman's Fracture: Technical Case Report
Authors: Bristol Ruth , Henn Jeffrey S. , Dickman Curtis A.
Published: February 2005

OBJECTIVE AND IMPORTANCE:

Traumatic spondylolisthesis of the axis may be treated by external immobilization or surgical fixation.

CLINICAL PRESENTATION:

We report the case of a 23-year-old man who sustained an Effendi Type II fracture of the axis, for which halo immobilization did not provide adequate stability.

INTERVENTION:

The unstable fracture was treated by placing lag screws in the pars interarticularis of C2, which reduced the fracture directly but sacrificed no normal spinal motion. The patient developed a solid fusion, and cervical alignment was normal at his 6-month follow-up examination.

CONCLUSION:

Although this technique has been reported previously, it is more commonly used in multilevel cervical fusions than for stand-alone repair of C2. Management options, anatomy, and technical considerations for the treatment of traumatic spondylolisthesis are reviewed.
Cervicothoracic Junction Arthroplasty after Previous Fusion Surgery for Adjacent Segment Degeneration: Case Report
Authors: Sekhon Lali H.S.
Published: February 2005

OBJECTIVE AND IMPORTANCE:

This is the first reported case of cervical arthroplasty using the Bryan Cervical Disc Prosthesis System (Medtronic Sofamor Danek, Inc., Memphis, TN) in the management of adjacent segment degeneration associated with previous fusion surgery and surgery at the cervicothoracic junction.

CLINICAL PRESENTATION:

This case report describes a 25-year-old woman who initially underwent a two-level anterior cervical fusion in 1998, 2 years after being involved in a motor vehicle accident. She was well until 18 months before presentation, when she developed bilateral shoulder pain, mechanical neck pain worse on flexion, and bilateral C8 distribution arm pain and paresthesia. On clinical examination, no focal deficits were found, although the range of motion was reduced. Preoperative cervical spine x-rays and magnetic resonance scanning confirmed accelerated degeneration of the C4–C5 and C7–T1 disc spaces, with evidence of neural compression at those levels.

INTERVENTION:

After careful consideration of various treatment options and failure of all conservative measures, the patient underwent an anterior C4–C5 and C7–T1 decompression with removal of the anterior cervical plate and placement of two artificial disc prostheses. After surgery, her course was uncomplicated and she was discharged from hospital well. There was complete resolution of the arm symptoms and reduction of the neck pain, with a reduction in the amount of analgesia she was taking. Seven months after surgery, she remains well with repeat x-rays confirming motion at the operated levels.

CONCLUSION:

This case demonstrates that cervical arthroplasty is a reasonable treatment option for patients who have had previous surgery in which interbody fusion has been performed and who have developed degeneration of adjacent levels. Despite the altered biomechanics at the cervicothoracic junction, no adverse features were noted with arthroplasty at this level.
Exposure of Midline Cranial Base without a Facial Incision through a Combined Craniofacial-Transfacial Procedure
Authors: Feiz-Erfan Iman , Han Patrick P. , Spetzler Robert F. , Porter Randall W. , Klopfenstein Jeffrey D. , Ferreira Mauro A.T. , Beals Stephen P. , Joganic Edward F.
Published: February 2005

OBJECTIVE:

A single-stage combined craniofacial-transfacial approach that exposes the midline cranial base without visible facial incisions is described.

METHODS:

Between 1992 and 1998, eight patients underwent surgery for five different anterior cranial base pathological findings: four angiofibromas, one mesenchymal chondrosarcoma, one esthesioneuroblastoma, one odontogenic myxoma, and one encephalocele. In all cases, the surgical exposure consisted of a bicoronal scalp incision with a bifrontal craniotomy and fronto-orbitonasal osteotomy, and then a sublabial incision for transmaxillary exposure.

RESULTS:

Gross total resection was achieved in five cases. The encephalocele was resected with complete reconstruction of the bony defect. Seven patients developed complications, primarily wound infections, cerebrospinal fluid leaks, and anemia. Postoperative Karnofsky Performance Scale scores ranged between 80 and 100 (mean, 92.5). Long-term follow-up information (mean, 56 mo; median, 59.5 mo; range, 5–108 mo) was available for all patients.

CONCLUSION:

Large anterior cranial base lesions can be resected and excellent cosmetic outcomes can be achieved with a single-stage combined transfacial-craniofacial approach that exposes the entire midline cranial base and requires no facial incisions.
Reconstruction Options for Complex Middle Cerebral Artery Aneurysms
Authors: Sekhar Laligam N. , Stimac Dinko , Bakir Abdurrahman , Rak Ramin
Published: February 2005

OBJECTIVE:

To describe techniques of reconstruction for unclippable and uncoilable middle cerebral artery aneurysms.

METHODS:

A retrospective review was performed of seven patients who underwent eight operations during a 9-year period to treat complex middle cerebral artery bifurcation aneurysms not amenable to direct clipping or endovascular coiling. All preoperative and postoperative clinical and imaging data were reviewed. Follow-up was obtained for all patients via clinic visit and/or telephone.

RESULTS:

The operative techniques used included saphenous vein graft bypass (n = 1), radial artery graft interposition (n = 2), radial artery patch (n = 1), superficial temporal artery interposition graft (n = 1), superior thyroid artery interposition graft (n = 1), direct reimplantation of branch (n = 1), and reconstruction of trifurcation (n = 1). There was no mortality. Six patients had excellent outcomes with Glasgow Outcome Scale scores of 5, and one patient had a good outcome with a Glasgow Outcome Scale score of 4.

CONCLUSION:

Techniques for middle cerebral artery reconstruction may remain important and useful in the age of endovascular aneurysm treatment.
Sequential Visualization of Brain and Fiber Tract Deformation during Intracranial Surgery with Three-dimensional Ultrasound: An Approach to Evaluate the Effect of Brain Shift
Authors: Coenen Volker A. , Krings Timo , Weidemann Jürgen , Hans Franz-Josef , Reinacher Peter , Gilsbach Joachim M. , Rohde Veit
Published: February 2005

OBJECTIVE:

We present a technique that allows intraoperative display of brain shift and its effects on fiber tracts.

METHODS:

Three patients had intracranial lesions (one malignant glioma, one metastasis, and one cavernoma) in contact with either the corticospinal or the geniculostriate tract that were removed microneurosurgically. Preoperatively, magnetic resonance diffusion-weighted imaging (DWI) was performed to visualize the fiber tract at risk. DWI data were fused with those obtained from anatomic T1-weighted magnetic resonance imaging. A single-rack three-dimensional ultrasound neuronavigation system, which simultaneously displays the MRI scan and the corresponding ultrasound image, was used intraoperatively for 1) navigation; 2) definition of fixed and potentially shifting ultrasound landmarks near the fiber tract; and 3) sequential image updating at different steps of resection. The result was time-dependent brain deformation data. With a standard personal computer equipped with standard image software, the brain shift-associated fiber tract deformation was assessed by use of sequential landmark registration. After surgery, DWI was performed to confirm the predicted fiber tract deformation.

RESULTS:

The lesions were removed without morbidity. Comparison of three-dimensional ultrasound with DWI and T1-weighted magnetic resonance imaging data allowed us to define fixed and potentially shifting landmarks close to the respective fiber tract. Postoperative DWI confirmed that the actual fiber tract position at the conclusion of surgery corresponded to the sonographically predicted fiber tract position.

CONCLUSION:

By definition and sequential intraoperative registration of ultrasound landmarks near the fiber tract, brain shift-associated deformation of a tract that is not visible sonographically can be assessed correctly. This approach seems to help identify and avoid eloquent brain areas during intracranial surgery.
Waterjet Dissection versus Ultrasonic Aspiration in Epilepsy Surgery
Authors: Oertel Joachim , Gaab Michael Robert , Runge Uwe , Schroeder Henry Werner Siegfried , Piek Juergen
Published: February 2005

OBJECTIVE:

Waterjet dissection is currently under close investigation in neurosurgery. Experimentally, precise brain parenchyma dissection with vessel preservation has been demonstrated. Clinically, the safety of the instrument has already been proved. However, precise data demonstrating that waterjet dissection indeed reduces surgical blood loss are still missing.

METHODS:

The authors applied the waterjet device in a prospective randomized study in comparison with the ultrasonic aspirator. Because there is little variability in the procedure, 30 patients with temporal lobe epilepsy receiving a tailored temporal lobe resection between December 1999 and October 2002 were selected for this study. Intraoperative vessel preservation, intraoperative blood loss, surgical complications, and epilepsy outcome were evaluated. All patients were followed at 3-month intervals.

RESULTS:

During surgery, both instruments were easy to handle. Only with the waterjet dissector, however, were even small intraparenchymal blood vessels preserved. Intraoperative blood loss was significantly reduced with the waterjet (mean, 70 ± 46 ml) compared with the ultrasonic aspirator (mean, 121 ± 48 ml). However, no difference in the necessity for blood transfusion occurred. No difference was observed with respect to operation time (238.6 ± 37.0 min with the waterjet, 247.5 ± 41.5 min with the ultrasonic aspirator), surgical complications, and outcome.

CONCLUSION:

The waterjet dissector enables a significant reduction of intraoperative blood loss in the investigated setting. However, further studies are needed to confirm these results with a larger number of patients. Studies also are needed to prove that the reduction of blood loss is of clinical relevance for the outcome of the patients.
Orbitozygomatic Approach to Basilar Apex Aneurysms
Authors: Hsu Frank P.K. , Clatterbuck Richard E. , Spetzler Robert F.
Published: February 2005

BASILAR APEX REGION aneurysms are among the most complex cerebral aneurysms. They are not, however, among the most common aneurysms, and increased use of endovascular treatment has further decreased the number of patients with these lesions who undergo surgery. Nonetheless, not all basilar apex aneurysms are amenable to coil embolization, and neurosurgeons must be prepared to treat patients with basilar apex aneurysms surgically. We prefer an orbitozygomatic craniotomy and transsylvian approach. Meticulous exercise of the basic tenets of aneurysm surgery (proximal vascular control, sharp dissection, and preservation of perforating vessels) is crucial to optimal patient outcomes.
Superficial Temporal Artery-to-Middle Cerebral Artery Bypass
Authors: Charbel Fady T. , Meglio Guido , Amin-Hanjani Sepideh
Published: February 2005

THE SUPERFICIAL TEMPORAL artery-to-middle cerebral artery bypass represents the mainstay of bypass operations for cerebral revascularization. The role of this operation in the setting of cerebrovascular occlusive disease, with compromised cerebral hemodynamic reserve, is a topic of current investigation. In this report, we describe technical nuances to avert potential pitfalls in the performance of this procedure. The use of intraoperative quantitative blood flow measurements as a reliable method of assessing the success of the bypass is also described.
Ideal Suture Diameter is Critical for Consistent Middle Cerebral Artery Occlusion in Mice
Authors: Türeyen Kudret , Vemuganti Raghu , Sailor Kurt A. , Dempsey Robert J.
Published: February 2005

OBJECTIVE:

The use of transgenic and knockout mice has led to a need for a consistent model of mouse transient focal cerebral ischemia. In a great majority of the published mouse middle cerebral artery (MCA) occlusion studies, the methods indicated the type of intraluminal suture used without indicating the actual suture diameter after modification. We attempted to determine the ideal suture diameter to produce consistent occlusion in the MCA of adult male C57BL/6 mice.

METHODS:

Suture tips were coated to a depth 4 mm with glue, and 6-0 sutures of eight different, precisely measured diameters were produced. The coated 6-0 sutures in different diameters were introduced 10 mm into the internal carotid artery via the external carotid artery of the mice to produce MCA occlusion (n = 40; five animals for each diameter), and the mice (22–24 g) were transaortically perfused with saline. The base of the brain was exposed, and photographs of the vessels were obtained before and after transaortic injection of Evans blue dye to determine the consistency of MCA occlusion for each suture diameter. Cerebral blood flow was measured 10 minutes before occlusion and 20 minutes after reperfusion, and 2,3,5-triphenyltetrazolium chloride staining was performed to demonstrate the ischemic damage in additional animals with 110-μm (n = 5) and 180-μm (n = 8) diameter sutures.

RESULTS:

Sutures measuring 170 μm and 180 μm in diameter consistently occluded the MCA of C57BL/6 mice. In addition, 2,3,5-triphenyltetrazolium chloride staining demonstrated consistent infarction with180-μm diameter sutures. The infarct volume was 36.3 ± 4.2 mm3.

CONCLUSION:

Small changes in the diameter of the occlusion suture tip affect consistency in the mouse MCA occlusion model.
Awake Craniotomy for Microsurgical Obliteration of Mycotic Aneurysms: Technical Report of Three Cases
Authors: Lüders Jürgen C. , Steinmetz Michael P. , Mayberg Marc R.
Published: February 2005

OBJECTIVE AND IMPORTANCE:

Infectious (mycotic) aneurysms that do not resolve with medical treatment require surgical obliteration, usually requiring sacrifice of the parent artery. In addition, patients with mycotic aneurysms frequently need subsequent cardiac valve repair, which often necessitates anticoagulation. Three cases of awake craniotomy for microsurgical clipping of mycotic aneurysms are presented. Awake minimally invasive craniotomy using frameless stereotactic guidance on the basis of computed tomographic angiography enables temporary occlusion of the parent artery with neurological assessment before obliteration of the aneurysm.

CLINICAL PRESENTATION:

A 56-year-old woman presented with progressively worsening mitral valve disease and a history of subacute bacterial endocarditis and subarachnoid hemorrhage 30 years previously. A cerebral angiogram revealed a 4-mm left middle cerebral artery (MCA) angular branch aneurysm, which required obliteration before mitral valve replacement. The second patient, a 64-year-old woman with a history of rheumatic fever, had an 8-mm right distal MCA aneurysm diagnosed in the setting of pulmonary abscess and worsening cardiac function as a result of mitral valve disease. The third patient, a 57-year-old man with a history of fevers, night sweats, and progressive mitral valve disease, had an enlarging left MCA angular branch aneurysm despite the administration of antibiotics. Because of their location on distal MCA branches, none of the aneurysms were amenable to preoperative test balloon occlusion.

INTERVENTION:

After undergoing stereotactic computed tomographic angiography with fiducial markers, the patients underwent a minimally invasive awake craniotomy with frameless stereotactic navigation. In all cases, the results of the neurological examination were unchanged during temporary parent artery occlusion and the aneurysms were successfully obliterated.

CONCLUSION:

Awake minimally invasive craniotomy for an infectious aneurysm located in eloquent brain enables awake testing before permanent clipping or vessel sacrifice. Combining frameless stereotactic navigation with computed tomographic angiography allowed us to perform the operation quickly through a small craniotomy with minimal exploration.