The complementary value of intraoperative fluorescence imaging and Raman spectroscopy for cancer surgery: combining the incompatibles.

A clear margin is an important prognostic factor for most solid tumours treated by surgery. Intraoperative fluorescence imaging using exogenous tumour-specific fluorescent agents has shown particular benefit in improving complete resection of tumour tissue. However, signal processing for fluorescence imaging is complex, and fluorescence signal intensity does not always perfectly correlate with tumour location. Raman spectroscopy has the capacity to accurately differentiate between malignant and healthy tissue based on their molecular composition. In Raman spectroscopy, specificity is uniquely high, but signal intensity is weak and Raman measurements are mainly performed in a point-wise manner on microscopic tissue volumes, making whole-field assessment temporally unfeasible. In this review, we describe the state-of-the-art of both optical techniques, paying special attention to the combined intraoperative application of fluorescence imaging and Raman spectroscopy in current clinical research. We demonstrate how these techniques are complementary and address the technical challenges that have traditionally led them to be considered mutually exclusive for clinical implementation. Finally, we present a novel strategy that exploits the optimal characteristics of both modalities to facilitate resection with clear surgical margins.

Glial cell line-derived neurotrophic factor in combination with insulin-like growth factor 1 and basic fibroblast growth factor promote in vitro culture of goat spermatogonial stem cells.

Growth factors are increasingly considered as important regulators of spermatogonial stem cells (SSCs). This study investigated the effects of various growth factors (GDNF, IGF1, bFGF, EGF and GFRalpha-1) on purification and colonization of undifferentiated goat SSCs under in vitro and in vivo conditions. Irrespective of the culture condition used, the first signs of developing colonies were observed from day 4 of culture onwards. The number of colonies developed in GDNF + IGF1 + bFGF culture condition was significantly higher than the other groups (p < 0.05). In contrast, the size of colonies developed in GDNF + EGF + LIF culture condition was significantly higher than the other groups (p < 0.05). Immunocytochemical stationing for specific biomarkers of somatic cells (vimentin, alpha-inhibin and α-SMA) and spermatogonial cells (PLZF, THY 1, VASA, alpha-1 integrin, bet-1 integrin and DBA) revealed that both cell types existed in developing colonies, irrespective of the culture condition used. Even though, the relative abundance of VASA, FGFR3, OCT4, PLZF, BCL6B and THY1 transcription factors in GDNF + IGF1 + bFGF treatment group was significantly higher than the other groups (p < 0.05). Additionally, goat SSCs developed in the latter culture condition could colonize within the seminiferous tubules of the germ-cell depleted recipient mice following xenotransplantation. Obtained results demonstrated that combination of GDNF with IGF1 and bFGF promote in vitro culture of goat SSCs while precludes uncontrolled proliferation of somatic cells.

Effect of varicocelectomy on sperm functional characteristics and DNA methylation.

In individuals with varicocele, DNA is damaged due to high level of oxidative stress, and varicocelectomy can overcome this effect. Damaged DNA is less liable to DNA methylation, and antioxidant therapy appears to have the potential to reduce sperm oxidative stress and DNA damage and thereby maintain DNA methylation, while effect of varicocelectomy on DNA methylation patterns has remained unclear. In the light of these considerations, we aimed to examine the effect of varicocelectomy on sperm DNA methylation and functional characteristics. Fifty-two men with left-sided varicocele (grade II &III) were included. Sperm parameters, DNA fragmentation, protamine deficiency, oxidative stress and global DNA methylation were evaluated before and 3 months after surgery. Our data show that sperm concentration, percentages of spermatozoon with abnormal morphology, DNA fragmentation, protamine deficiency and oxidative stress significantly improved after surgery. Percentage of sperm motility, global DNA methylation and intensity of DNA methylation also improved after surgery, although the differences were not significant when compared with before surgery. Categorisation of individuals to subgroups revealed that improvement of DNA methylation appears to take place in oligozoospermic individuals, which are more severely affected by state of varicocele. However, this is a preliminary study, and further studies are required to solidify this conclusion.

Effect of warm bupivacaine on the sensory onset of epidural anaesthesia in lower limb orthopaedic surgery: a double-blind randomized clinical trial.

PURPOSE OF THE STUDY: In this study we evaluated the effect of warm bupivacaine on the onset time of sensory block in patients undergoing lower limb surgery with epidural anaesthesia METHODS: After approval by the Ethics Committee and written informed consents, 60 ASA physical status I and II patients, aged 18 to 75 years, undergoing elective lower limb surgery were studied in this randomized double-blind clinical trial. The patients having spinal anesthesia were divided into two groups. Group 1 received warm bupivacaine and group 2 was given bupivacaine at room temperature. The onset time and the level of sensory block were evaluated by a blind observer. Side effects (nausea, vomiting, shivering, headache, low back pain) were evaluated during surgery and in the post-operative period. RESULTS: One patient was excluded from the study because of incomplete block; therefore 59 patients in two groups (29 patients in group 1 and 30 patients in group 2) were compared. The groups were matched on gender, age, weight and BMI. The onset time of sensory block at the levels of T12, L3 and L4 in group 1 was significantly shorter than in group 2 (p < 0.001). The difference in the onset time of sensory block at the upper levels of the spine between the two groups was not significant (p = 0.21). The incidence of side effects did not differ significantly (p = 0.18) between the two groups. CONCLUSIONS: Warming bupivacaine can decrease the onset time of sensory block in epidural anaesthesia without any side effects in patients undergoing lower limb orthopaedic surgery.

Role of Date Palm Pollen on Heifer's Puberty and Maturity in Iraq.

The use of herbal remedies has played a crucial role throughout medicine, and human beings have always used these valuable resources to treat their health problems and diseases. Phoenix dactylifera (Palm) is one of the most famous medicinal plants. Therefore, this study was designed to investigate the possible effects of date palm pollen supplementation on the heifer's puberty. This study was conducted in Najaf- Iraq, on 10 crossbred heifers 6 months old, from December 1st, 2021, to August 1st, 2022. The animals were divided randomly into two groups: T1 was supplemented with 2g of date palm pollen (DPP) plus the main ration, while T2 was supplemented only with the main ration. The results revealed a significant effect (P<0.05 and P<0.01) in T1 over T2, accelerating the heifer's puberty and sexual maturity. The results also showed a significant effect (P<0.01) between T1 and T2 at the level of the hormones FSH, LH and estrogen in the age of puberty, as well as the presence of a significant difference (P<0.01) and (P<0.05) between T1 and T2 at the level of the hormones FSH and estrogen in the age of sexual maturity. The results also showed a significant effect (P<0.05) for T1 and T2 in weight at puberty and maturity. This study aimed to accelerate puberty and sexual maturity in the heifers.

Cold plasma enamel surface treatment to increase fluoride varnish uptake.

Among the available methods of enamel strengthening, fluoride varnish (FV) treatment has relatively better results. On the other hand, cold plasma technology has shown promising capacities in sterilizing the environment, surface modification, and improving adhesion. Accordingly, this study aimed to increase the adhesion of FV to the enamel surface to prolong the enamel interaction with FV with subsequently increased fluoride uptake by enamel. Emphasizing that the change in adhesion is evidence-based and has not been explicitly measured. For this purpose, we randomly divided twenty bovine teeth into two groups A (consisting of four teeth) and B (composed of four subgroups, each containing four teeth). Samples of group A and one specimen of each subset B investigated the effect of using Helium-DBD (He-DBDJ), Argon (ArJ), and Air-DBD jet on the enamel surface. Other B specimens are devoted to studying the release of FV fluoride ions from processed enamel. Two diagnostic techniques, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), have been utilized to examine the samples' surface morphology and chemical analysis, respectively. Finally, the release of fluoride ions into distilled water was measured by an ion-selective electrode (ISE). SEM images showed that ArJ and Air-DBD significantly damaged enamel hexagonal structures, whereas, in the case of He-DBDJ, the hexagonal structures have only altered from convex to concave. EDX indicated an increase in calcium to phosphorus ratio and the amount of fluoride and sodium uptake on the enamel surface layer in the group processed with He-DBDJ plasma. The latter helps restore the damaged parts of the enamel. Analysis of fluoride released from the FV did not show a significant change owing to plasma processing (P ≤ 0.112). The combination of cold plasma and fluoride varnish treatment on the enamel surface might be considered as a more promising approach to increasing enamel resistance to tooth decay.

Zaditen (Ketotifen), as mast cell blocker, improves sperm quality, chromatin integrity and pregnancy rate after varicocelectomy.

Surgery is considered the most common choice for the treatment of male infertility with clinical varicocele. Increased numbers of mast cells (MCs) have been associated with different types of infertility, including varicocele. Despite there being different reports on improved fertility following administration of MC blockers, there is no report on the effect of a MC blocker on varicocele or after varicocelectomy. Therefore, the aim of this study was to evaluate the effect of Zaditen on semen quality, protamine content, DNA damage and fertility post-surgery. The study included 103 infertile men who were referred to Isfahan Fertility and Infertility Center for varicocelectomy. Varicocele individuals were randomly divided into control (52) and treatment groups (51). Semen parameters, WBC/mL, protamine content (chromomycin A3 staining) and DNA integrity (sperm chromatin dispersion test) were assessed before and 3 months after surgery. Comparison of the aforesaid parameters between the two groups revealed significant improvement in the treatment group compared with the control group, with the exception of DNA integrity. In addition, the cumulative pregnancy significantly improved by 9 months post-surgery in the treatment group (41.17%) compared with the control group (21.15%). The results of this study, for the first time, reveal that MC blockers such as Zaditen improve semen parameters, chromatin integrity and pregnancy rates when administered as adjunct therapy post-varicocelectomy.

Comparison of plaque removal efficacy of new and 3-month-old toothbrushes in children.

The cost of replacing toothbrushes at frequent intervals may be prohibitive in underdeveloped countries. The objective of this study in Tehran was to compare the plaque removal efficacy of new and 3-month-old toothbrushes in children. In a randomized, crossover study, 93 children aged 7-9 years old received a new manual toothbrush to use twice per day for 3 months. Plaque scores were measured using the modified Quigley-Hein plaque index after children had brushed for 60 seconds with either a new or their used toothbrush. Bristle wear of worn brushes was assessed by measuring brushing surface areas on digital images. Compared with new brushes in the same subjects, no statistically significant differences were found for plaque score reductions for 3-month-old toothbrushes exhibiting various degrees of wear. Worn toothbrushes are equally effective as new ones for children.

Effect of biosal®, deltamethrin and lambda-cyhalothrin on the activity of GOT, GPT and total protein contents in two fodder pests Hermolaus modestus and Hermolaus ocimumi.

The assessment of the comparative effect of biosal (phytopesticide), deltamethrin, and lambda-cyhalothrin (pyrethroids) were made against two fodder pests, Hermolaus modestus and Hermolaus ocimumi by filter paper impregnation method. The activity of total protein contents, GPT (glutamic-pyruvic transaminase) and GOT (glutamic oxaloacetate transaminase) were affected in Hermolaus modestus and Hermolaus ocimumi against biosal, deltamethrin, and lambda cyhalothrin. The activity of total protein contents in H. modestus was 31.053%, 4.607%, and 24.575%, against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The activity of total protein contents was observed as 24.202%, 15.25%, and 56.036% against deltamethrin, lambda-cyhalothrin, and biosal, respectively in H. ocimumi. The activity of GOT was observed as 98.675% for biosal 33.95% for deltamethrin and 83.619% for lambda-cyhalothrin in H. modestus. The GOT activity was estimated in H. ocimumi as 78.831%, 47.645%, and 71.287% against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The efficacy of GPT enzyme against biosal, deltamethrin, and lambda-cyhalothrin was calculated as 89.26%, 73.07%, and 47.58%, respectively in H. modestus. The H. ocimumi showed GPT activity as 77.58% for biosal, 68.84% for deltamethrin, and 52.67% for lambda-cyhalothrin, respectively.

Effect of biosal®, deltamethrin and lambda-cyhalothrin on the activity of GOT, GPT and total protein contents in two fodder pests Hermolaus modestus and Hermolaus ocimumi

Abstract The assessment of the comparative effect of biosal (phytopesticide), deltamethrin, and lambda-cyhalothrin (pyrethroids) were made against two fodder pests, Hermolaus modestus and Hermolaus ocimumi by filter paper impregnation method. The activity of total protein contents, GPT (glutamic-pyruvic transaminase) and GOT (glutamic oxaloacetate transaminase) were affected in Hermolaus modestus and Hermolaus ocimumi against biosal, deltamethrin, and lambda cyhalothrin. The activity of total protein contents in H. modestus was 31.053%, 4.607%, and 24.575%, against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The activity of total protein contents was observed as 24.202%, 15.25%, and 56.036% against deltamethrin, lambda-cyhalothrin, and biosal, respectively in H. ocimumi. The activity of GOT was observed as 98.675% for biosal 33.95% for deltamethrin and 83.619% for lambda-cyhalothrin in H. modestus. The GOT activity was estimated in H. ocimumi as 78.831%, 47.645%, and 71.287% against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The efficacy of GPT enzyme against biosal, deltamethrin, and lambda-cyhalothrin was calculated as 89.26%, 73.07%, and 47.58%, respectively in H. modestus. The H. ocimumi showed GPT activity as 77.58% for biosal, 68.84% for deltamethrin, and 52.67% for lambda-cyhalothrin, respectively.

Resumo A avaliação do efeito comparativo do biosal (fitopesticida), deltametrina e lambda-cialotrina (piretróides) foi feita contra duas pragas forrageiras, Hermolaus modestus e Hermolaus ocimumi, pelo método de impregnação com papel de filtro. A atividade do conteúdo de proteína total, GPT (transaminase glutâmico-pirúvica) e GOT (oxaloacetato transaminase glutâmico) foram afetados em Hermolaus modestus e Hermolaus ocimumi contra biosal, deltametrina e lambda cialotrina. A atividade do conteúdo de proteína total em H. modestus foi 31.053%, 4.607% e 24.575%, contra biosal, deltametrina e lambda-cialotrina, respectivamente. A atividade do conteúdo de proteína total foi observada como 24.202%, 15.25% e 56,036% contra deltametrina, lambda-cialotrina e biosal, respectivamente em H. ocimumi. A atividade do GOT foi observada em 98.675% para o biosal, 33,95% para a deltametrina e 83.619% para a lambda-cialotrina em H. modestus. A atividade do GOT foi estimada em H. ocimumi como 78.831%, 47.645% e 71.287% contra biosal, deltametrina e lambda-cialotrina, respectivamente. A eficácia da enzima GPT contra biosal, deltametrina e lambda-cialotrina foi calculada como 89.26%, 73.07% e 47.58%, respectivamente em H. modestus. A H. ocimumi apresentou atividade GPT de 77.58% para biosal, 68.84% para deltametrina e 52.67% para lambda-cialotrina, respectivamente.

Effect of biosal®, deltamethrin and lambda-cyhalothrin on the activity of GOT, GPT and total protein contents in two fodder pests Hermolaus modestus and Hermolaus ocimumi / Efeito do biosal®, deltametrina e lambda-cialotrina na atividade do GOT, GPT e conteúdo de proteína total em duas pragas forrageiras Hermolaus modestus e Hermolaus ocimumi

Abstract The assessment of the comparative effect of biosal (phytopesticide), deltamethrin, and lambda-cyhalothrin (pyrethroids) were made against two fodder pests, Hermolaus modestus and Hermolaus ocimumi by filter paper impregnation method. The activity of total protein contents, GPT (glutamic-pyruvic transaminase) and GOT (glutamic oxaloacetate transaminase) were affected in Hermolaus modestus and Hermolaus ocimumi against biosal, deltamethrin, and lambda cyhalothrin. The activity of total protein contents in H. modestus was 31.053%, 4.607%, and 24.575%, against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The activity of total protein contents was observed as 24.202%, 15.25%, and 56.036% against deltamethrin, lambda-cyhalothrin, and biosal, respectively in H. ocimumi. The activity of GOT was observed as 98.675% for biosal 33.95% for deltamethrin and 83.619% for lambda-cyhalothrin in H. modestus. The GOT activity was estimated in H. ocimumi as 78.831%, 47.645%, and 71.287% against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The efficacy of GPT enzyme against biosal, deltamethrin, and lambda-cyhalothrin was calculated as 89.26%, 73.07%, and 47.58%, respectively in H. modestus. The H. ocimumi showed GPT activity as 77.58% for biosal, 68.84% for deltamethrin, and 52.67% for lambda-cyhalothrin, respectively.

Resumo A avaliação do efeito comparativo do biosal (fitopesticida), deltametrina e lambda-cialotrina (piretróides) foi feita contra duas pragas forrageiras, Hermolaus modestus e Hermolaus ocimumi, pelo método de impregnação com papel de filtro. A atividade do conteúdo de proteína total, GPT (transaminase glutâmico-pirúvica) e GOT (oxaloacetato transaminase glutâmico) foram afetados em Hermolaus modestus e Hermolaus ocimumi contra biosal, deltametrina e lambda cialotrina. A atividade do conteúdo de proteína total em H. modestus foi 31.053%, 4.607% e 24.575%, contra biosal, deltametrina e lambda-cialotrina, respectivamente. A atividade do conteúdo de proteína total foi observada como 24.202%, 15.25% e 56,036% contra deltametrina, lambda-cialotrina e biosal, respectivamente em H. ocimumi. A atividade do GOT foi observada em 98.675% para o biosal, 33,95% para a deltametrina e 83.619% para a lambda-cialotrina em H. modestus. A atividade do GOT foi estimada em H. ocimumi como 78.831%, 47.645% e 71.287% contra biosal, deltametrina e lambda-cialotrina, respectivamente. A eficácia da enzima GPT contra biosal, deltametrina e lambda-cialotrina foi calculada como 89.26%, 73.07% e 47.58%, respectivamente em H. modestus. A H. ocimumi apresentou atividade GPT de 77.58% para biosal, 68.84% para deltametrina e 52.67% para lambda-cialotrina, respectivamente.

Comparative dynamics of 5-methylcytosine reprogramming and TET family expression during preimplantation mammalian development in mouse and sheep.

Despite previous assumption that paternal active DNA demethylation is an evolutionary conserved phenomenon in mammals, emerging studies in other species, particularly sheep, do not support this issue. Recently, ten eleven translocation (TET) enzymes have been suggested as intermediates in genome-wide DNA demethylation through the iterative conversion of five methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC)/5-formylcytosine/5-carboxylcytosine (5caC) derivatives. This study investigated whether TET enzymes and 5mC derivatives are also involved in dynamic reprogramming of early sheep embryos derived by fertilization. Mouse zygotes and developing embryos were considered as control. Obtained results reported substantial differences in dynamics of parent-of-origin-specific patterns of 5mC reprogramming and generation/dilution of 5mC derivatives (5hmC and 5caC) between mouse and sheep early zygotes. Sheep zygotes reported a gradual and insignificant decrease pattern of parental pronucleus 5mC, which was notably replication independent, coincided with gradual generation of 5hmC and 5caC. Although the expression profiles of TET family of enzymes (Tet1, Tet2, and Tet3), with the main exception being Tet2 at later developmental stages, were similar between mouse and sheep developing embryos. In addition, although the expression level of Tet3 was higher than Tet1 and Tet2 in MII oocytes and zygotes in both mouse and sheep, the expression of Tet3 in mouse was higher than sheep in both MII oocytes and zygotes. The contrasting dynamics of 5mC reprogramming between these two species may be associated with the particular evolutionary differences that exist between developmental program of rodents and ruminants, particularly during peri-implantation stages.

Determination of germanium by AAS in chloride-containing matrices.

Interference effects of NaCl on the ET-AAS determination of Ge have been studied. The use of several matrix modifiers to alleviate this problem such as Ni and Zn perchlorates and nitrates, nitric acid, ammonium nitrate are reported. The stabilizing effect of Zn and Ni perchlorates allows the use of high pretreatment temperatures. NaCl is thus thermally volatilized from the atomizer by employing pretreatment temperatures higher than 1500 degrees C resulting in an improved sensitivity. Germanium levels in zinc plant slag samples, have been determined and compared to those obtained for the same samples spiked with NaCl with platform and wall atomization using nickel perchlorate as a matrix modifier. The results were compared with those from a hydride generation system equipped with a liquid nitrogen trap. The recoveries for germanium have been almost complete and amount to 99% for the original slag samples and 80% for 15% (w/w) NaCl containing spiked samples.

Interaction of a relativistic soliton with a nonuniform plasma.

By using a relativistic fluid model, a nonlinear theory for the propagation of an intense laser pulse in an inhomogeneous cold plasma is developed. Assuming that the radiation spot size is larger than the plasma wavelength, we derive an envelope equation for the momentum of the electron fluid, taking into account relativistic electron mass variation and finite amplitude electron density perturbations that are driven by the relativistic ponderomotive force of light. Localized solutions of the envelope equation are discussed from an energy integral containing an effective potential. Numerical results for envelope solitons are obtained in a quasistationary approximation. The dependency of these localized solutions on the amplitude and the group velocity of the laser pulse is discussed. Also derived is an equation that governs the dynamics of the pulse center.

The effect of vertical dimension and mandibular position on isometric strength of the cervical flexors.

This study compared the peak isometric strength of the cervical flexors in deep bite temporomandibular dysfunction (TMD) patients while biting in four bite positions: habitual occlusion, edge-to-edge, lateral shift and retruded. These values were then compared to those of the same subjects' bite positions elevated to a functional criterion (maximum isometric strength of the deltoid muscles). The mean height increase was 2.4 mm with a range of 1.5-3.8 mm. Fifteen of eighteen deep bite subjects met an inclusionary criterion, at least 13.3 Newtons (N) stronger cervical muscle strength with mandible relaxed open than habitual bite. Peak strength biting edge-to-edge was significantly greater than biting in habitual occlusion. Strength was found to increase significantly when biting in each of four mandibular positions when the bite was elevated to the functional criterion. The greatest strength was obtained from elevated habitual and edge-to-edge positions. The findings are of clinical significance, suggesting that cervical muscle isometric strength is affected by bite position and vertical dimension of occlusion. The results suggest that when biting, individuals with deep bite may be functioning at about 60% of their potential cervical flexor, isometric strength. The interaction between occlusal position, vertical dimension and cervical muscle function suggests a craniomandibular-cervical masticatory system.

Telepathology in neurosurgery.

In most tumor cases of neurosurgery, we need to have a rapid section diagnostic of the tumor during the course of surgery. When we have received the results that diagnose the exact dignity of the tumor, we devise the operation strategy for the continuing course of surgery. The tissue sample is sent by taxi to the pathological institute in Heidelberg. It takes approximately 45-60 min until we receive the results by telephone. Many centers are far away from a pathological institute and the patient may need to be re-operated on there. In stereotaxy it is still more important. We need approximately 15-25 specimens during a stereotaxy, so we can be sure we have a sample with some of the tumor tissue present. With direct contact to a pathological institute we could reduce this dramatically. We prepared a methylen blue slide and used a histological microscope with a video camera attached to it and a digitizer interface for digitized pictures. By use of a modem we send the pictures by telephone line to the pathological institute, where they are assessed. We currently have direct contact with a pathologist so they can tell us from which part of the tumor we should send the other histological pictures. The procedure takes about twenty minutes. By using this procedure the distance to the pathological institute is irrelevant. The system costs approximately $10,000, covering the cost mostly of the microscope and the camera (but we already had the microscope) and can be built by anybody with minimal requirements.

A comparative statistical analysis of neuronavigation systems in a clinical setting.

The use of neuronavigation (NN) in neurosurgery has become ubiquitous. A growing number of neurosurgeons are utilizing NN for a wide variety of purposes, including optimizing the surgical approach (macrosurgery) and locating small areas of interest (microsurgery). The goal of our team is to apply rapid advances in hardware and software technology to the field of NN, challenging and ultimately updating current NN assumptions. To identify possible areas in which new technology may improve the surgical applications of NN, we have assessed the accuracy of neuronavigational measurements in the Radionics and BrainLab systems. Using a phantom skull, we measured how accurate the visualization of a navigational probe's tip was in these systems, taking a total of 2180 measurements. We found that, despite current NN tenets, error is maximal at the six marker count and minimal in the spreaded marker setting; that is, placing less markers around the area of interest maximizes accuracy and active tracking does not necessarily increase accuracy. Comparing the two systems, we also found that accuracy of NN machines differs both overall and in different axes. As researchers continue to apply technological advances to the NN field, an increasing number of currently held tenets will be revised, making NN an even more useful tool in neurosurgery.

Quantification of the gravity-dependent change in the C-arm image center for image compensation in fluoroscopic spinal neuronavigation.

In the quest to develop a viable, frameless spinal navigation system, many researchers are utilizing the C-arm fluoroscope. However, there is a significant problem with the C-arm that must be quantified: the gravity-dependent sag effect resulting from the geometry of the C-arm and aggravated by the inequity of weight at each end of the C-arm. This study quantified the C-arm sag effect, giving researchers the protocol and data needed to develop a program that accounts for this distortion. The development of spinal navigation algorithms that account for the C-arm sag effect should produce a more accurate spinal navigation system.

Neuronavigational epilepsy focus mapping.

The localization of a seizure focus for resective surgery often requires invasive monitoring for precise localization of the target as well as structures to avoid. We report on the use of intra-operative surgical navigation to precisely localize and co-register subdural electrodes to regions of know radiographic pathology. Additionally, the navigation system was used to develop intra-operative electrode maps. These maps were subsequently used in the sub-acute recording phase to assign electrographic pathology and function (e.g. speech) to a specific cortical surface anatomy. This permitted for more precise planning of surgery and better assessment of potential risk, based on functional as well as anatomical criterion.