Biporous silica nanostructure-induced nanovortex in microfluidics for nucleic acid enrichment, isolation, and PCR-free detection

Efficient pathogen enrichment and nucleic acid isolation are critical for accurate and sensitive diagnosis of infectious diseases, especially those with low pathogen levels. Our study introduces a biporous silica nanofilms-embedded sample preparation chip for pathogen and nucleic acid enrichment/isolation. This chip features unique biporous nanostructures comprising large and small pore layers. Computational simulations confirm that these nanostructures enhance the surface area and promote the formation of nanovortex, resulting in improved capture efficiency. Notably, the chip demonstrates a 100-fold lower limit of detection compared to conventional methods used for nucleic acid detection. Clinical validations using patient samples corroborate the superior sensitivity of the chip when combined with the luminescence resonance energy transfer assay. The enhanced sample preparation efficiency of the chip, along with the facile and straightforward synthesis of the biporous nanostructures, offers a promising solution for polymer chain reaction-free detection of nucleic acids.

Programming Anisotropic Functionality of 3D Microdenticles by Staggered-Overlapped and Multilayered Microarchitectures

Natural sharkskin features staggered-overlapped and multilayered architectures of riblet-textured anisotropic microdenticles, exhibiting drag reduction and providing a flexible yet strong armor. However, the artificial fabrication of three-dimensional (3D) sharkskin with these unique functionalities and mechanical integrity is a challenge using conventional techniques. In this study, it is reported on the facile microfabrication of multilayered 3D sharkskin through the magnetic actuation of polymeric composites and subsequent chemical shape fixation by casting thin polymeric films. The fabricated hydrophobic sharkskin, with geometric symmetry breaking, achieves anisotropic drag reduction in frontal and backward flow directions against the riblet-textured microdenticles. For mechanical integrity, hard-on-soft multilayered mechanical properties are realized by coating the polymeric sharkskin with thin layers of zinc oxide and platinum, which have higher hardness and recovery behaviors than the polymer. This multilayered hard-on-soft sharkskin exhibits friction anisotropy, mechanical robustness, and structural recovery. Furthermore, coating the MXene nanosheets provides the fabricated sharkskin with a low electrical resistance of ≈5.3 Ω, which leads to high Joule heating (≈229.9 °C at 2.75 V). The proposed magnetomechanical actuation-assisted microfabrication strategy is expected to facilitate the development of devices requiring multifunctional microtextures.

Electroconvective viscous fingering in a single polyelectrolyte fluid on a charge selective surface

When a low-viscosity fluid displaces into a higher-viscosity fluid, the liquid-liquid interface becomes unstable causing finger-like patterns. This viscous fingering instability has been widely observed in nature and engineering systems with two adjoined fluids. Here, we demonstrate a hitherto-unrealizable viscous fingering in a single fluid-solid interface. In a single polyelectrolyte fluid on a charge selective surface, selective ion rejection through the surface initiates i) stepwise ion concentration and viscosity gradient boundaries in the fluid and ii) electroconvective vortices on the surface. As the vortices grow, the viscosity gradient boundary pushes away from the surface, resulting viscous fingering. Comparable to conventional one with two fluids, i) a viscosity ratio ([Formula: see text]) governs the onset of this electroconvective viscous fingering, and ii) the boundary properties (finger velocity and rheological effects) - represented by [Formula: see text], electric Rayleigh ([Formula: see text]), Schmidt ([Formula: see text]), and Deborah ([Formula: see text]) numbers - determine finger shapes (straight v.s. ramified, the onset length of fingering, and relative finger width). With controllable onset and shape, the mechanism of electroconvective viscous fingering offers new possibilities for manipulating ion transport and dendritic instability in electrochemical systems.

Induced-charge membrane capacitive deionization enables high-efficient desalination with polarized porous electrodes

Exposure of a conducting porous material to an electric field in electrolytes induces an electric dipole, which results in capacitive charging of cations and anions at opposite poles. In this letter, we investigate a novel desalination method using this induced-charge capacitive deionization (ICCDI). To do this, we devise a microscale ICCDI platform that can visualize in situ ion concentrations, pH shifts, and fluid flows, and study ion transport dynamics and desalination performances compared to conventional CDI with unipolar / bipolar connections. Similar ion concentration and fluid flow characteristics were observed in Ohmic, limiting, and over-limiting regimes, but variations in desalination performance trends were noted based on the number of stacks. In a single cell, ICCDI generates a higher electric field at the opposite poles of porous electrodes than simple conducted electrodes in CDIs with unipolar/bipolar connections, leading to superior salt removal and/or lower ionic current at a given applied voltage. This marks a clear contrast from CDI with bipolar connection, which lacks any advantage over CDI with unipolar connection in a single cell. These metrics of ICCDI however deteriorated as the stack number increased, likely due to short-circuiting between the dipoles. As a result, ICCDI in current form shows higher desalination efficient than conventional CDIs with low stack numbers (< 6), so we offer the scale-up module by repeating 4-stack ICCDI units. Our study enhances comprehension of ion transport dynamics and desalination performance in ICCDI, and the results could aid in the development of ICCDI for energy/cost-efficient desalination.

An epifluidic electronic patch with spiking sweat clearance for event-driven perspiration monitoring

Sensory neurons generate spike patterns upon receiving external stimuli and encode key information to the spike patterns, enabling energy-efficient external information processing. Herein, we report an epifluidic electronic patch with spiking sweat clearance using a sensor containing a vertical sweat-collecting channel for event-driven, energy-efficient, long-term wireless monitoring of epidermal perspiration dynamics. Our sweat sensor contains nanomesh electrodes on its inner wall of the channel and unique sweat-clearing structures. During perspiration, repeated filling and abrupt emptying of the vertical sweat-collecting channel generate electrical spike patterns with the sweat rate and ionic conductivity proportional to the spike frequency and amplitude over a wide dynamic range and long time (> 8 h). With such 'spiking' sweat clearance and corresponding electronic spike patterns, the epifluidic wireless patch successfully decodes epidermal perspiration dynamics in an event-driven manner at different skin locations during exercise, consuming less than 0.6% of the energy required for continuous data transmission. Our patch could integrate various on-skin sensors and emerging edge computing technologies for energy-efficient, intelligent digital healthcare.

Clinical and histologic features associated with lentigo maligna clearance after imiquimod treatment

BACKGROUND

Imiquimod cream may be used as a non-surgical treatment for lentigo maligna or as adjuvant therapy following excision to decrease the risk of recurrence.

OBJECTIVES

To evaluate histologic and clinical factors associated with clinical clearance of lentigo maligna treated with imiquimod.

METHODS

We performed a retrospective review of all patients diagnosed with lentigo maligna and treated with imiquimod between 1997 and 2019 at our academic institution.

RESULTS

We observed clinical clearance in 93% (66/71) of participants who received adjuvant imiquimod following surgery and 79% (19/24) in the primary non-surgical treatment group over a median of 38 months of follow-up. In the adjuvant therapy group, positive surgical margins were associated with a decreased rate of clinical clearance when compared to cases with close (<1 mm) margins or background melanocytic dysplasia (83.3 vs. 100%, p = .01). The presence of an inflammatory response during treatment was associated with increased clearance (94.1 vs. 66.7%, p = .02).

CONCLUSIONS

Adjuvant imiquimod treatment may decrease LM recurrence rates in cases with background melanocytic dysplasia or close margins. LM cases with positive surgical margins need close clinical follow-up given higher recurrence rates.

Pattern Formation of Three-Dimensional Electroconvection on a Charge Selective Surface

When a charge selective surface consumes or transports only cations or anions in the electrolyte, biased ion rejection initiates hydrodynamic instability, resulting in vortical fluid motions called electroconvection. In this Letter, we describe the first laboratory observation of three-dimensional electroconvection on a charge selective surface. Combining experiment and scaling analysis, we successfully categorized three distinct patterns of 3D electroconvection according to [(Ra_{E})/(Re^{2}Sc)] [electric Rayleigh number (Ra_{E}), Reynolds number (Re), Schmidt number (Sc)] as (i) polygonal, (ii) transverse, or (iii) longitudinal rolls. If Re increases or Ra_{E} decreases, pure longitudinal rolls are presented. On the other hand, transverse rolls are formed between longitudinal rolls, and two rolls are transformed as polygonal one at higher Ra_{E} or lower Re. In this pattern selection scenario, Sc determines the critical electric Rayleigh number (Ra_{E}^{*}) for the onset of each roll, resulting in Ra_{E}^{*}∼Re^{2}Sc. We also verify that convective ion flux by electroconvection (represented by an electric Nusselt number Nu_{E}) is fitted to a power law, Nu_{E}∼[(Ra_{E}-Ra_{E}^{*})/(Re^{2}Sc)]^{α_{1}}Re^{α_{2}}Pe^{α_{3}} [Péclet number (Pe)], where each term represents the characteristics of electroconvection, shear flow, and ion transport.

Microscale electrodeionization: In situ concentration profiling and flow visualization

Electrodeionization (EDI) is membrane-based desalination utilizing ion exchange membranes and ion exchange resins. By combining Electrodialysis and Ion exchanger, EDI can produce ultrapure water in a continuous-flow manner. Although its theoretical mechanisms are well documented, there is no experimental platform that can provide microscopic details inside of the system. In this paper, we present microscale EDI that can visualize in situ ion concentration, pH, and fluid flows. The platform was fabricated by filling ion exchange resins as a monolayer in a transparent polydimethylsiloxane channel between cation and anion exchange membranes. According to operating voltages (0-15V), distinct behaviors of ion concentration profile, pH shift, and fluid flows were observed in Ohmic, limiting, and overlimiting regimes. It is noteworthy that overlimiting regimes can be sub-categorized as water-splitting and electroconvection regimes. In the early stage (4-8V), water-splitting is dominant with pH change near the membranes and resins; under a higher voltage (8-15V), electroconvection starts to occur even water-splitting tries to suppress the development of the extended space charge layer and corresponding electroconvective instability. Accelerated ionic migration by electroconvection can improve current efficiency up to 80%. This is a clear departure from overlimiting dynamics in electrodialysis (with electroconvection only), ion exchanger (with no distinct regime), and even from that in previous EDI experiments (with water splitting only).

Simultaneous electric production and sizing of emulsion droplets in microfluidics

Microscale emulsions are widely used in fundamental and applied sciences. To expand their utilization, various methods have been developed for manipulating and measuring the physical properties of fabricated emulsions inside microchannels. Herein, we present an electric emulsification platform that can produce emulsions and simultaneously detect their physical properties (size and production speed). The characterization of the emulsion properties during the fabrication process will broaden the application fields for microscale emulsions because it can avoid time-consuming post image processing and simplify the emulsification platform. To accomplish this, a "bottleneck" channel is implanted between two reservoirs of immiscible fluids (continuous and dispersion phases). This channel can not only confine one fluid within the other when the electric field is on, resulting in emulsification via electrohydrodynamically induced Rayleigh instability, but also act as a resistive pulse sensor (RPS). The fluctuation of the liquid/liquid interface during emulsification induces the fluctuation of the electric resistance in the bottleneck channel, as the two fluid phases have different electrical conductivities. With this simple but dual-functional channel, the emulsion size (radius of 5-10 μm) and production speed (7-12 Hz) can be controlled by adjusting the electric field and the channel-neck geometry. Additionally, the properties can be measured using the RPS; the data obtained through the RPS exhibit high correlations with the validated data obtained using a high-speed camera and microscopy (>95%). The proposed buffer-less electric emulsification with the embedded RPS is a simple and cost-effective emulsion production method that allows real-time emulsion characterization with a limited sample volume.

Corrigendum: Purification of High Salinity Brine by Multi-Stage Ion Concentration Polarization Desalination

This corrects the article DOI: 10.1038/srep31850.

Half-Cell Ion Concentration Polarization on Nafion-Coated Electrode

On ion-selective membranes, cation/anion-selective transport under electric field initiates ion concentration polarization (ICP); ion concentration increases at one side of the membrane (ion enrichment), whereas it decreases at the other side (ion depletion). This polarization always occurs as the pair of ion enrichment and ion depletion. Departing from such pair generation, we demonstrate that only half of ICP (either ion enrichment or ion depletion) can be solitary on a Nafion-coated electrode. Current-voltage-time responses and conductance measurement capture this half-cell ICP with qualitative in situ pH/ion concentration visualization. In this half-cell, ion depletion hinders an ion flux, whereas ion enrichment facilitates the flux, so a diode-like current rectification is observed even in high-voltage regime (<±200 V) with a rectification factor up to 500. The results in this work give us deeper understanding about ICP on the electrodes and also open the possibility to use half-cell ICP as a high-voltage ionic diode and related sensing/energy applications.

Transient Swell of a High Density Polyethylene Using Adjustable Gap Slit Die

A novel slit die with an adjustable gap is designed to perform transient swell measurements while changing the die gap dynamically. A generalized control model is developed to predict time-dependent swell using characteristic relaxation time and corresponding steady state swell as model parameters. Further, a series of slit dies are designed and used to measure steady state thickness swell of a high-molecular-weight blow-molding grade high density polyethylene resin under various operating and geometrical conditions. A generalized expression for steady state thickness swell is obtained by applying multi-variable nonlinear regression on thus obtained steady state thickness swell data, and is used in the empirical control model to predict transient extrudate swell.

Partially Cured Photopolymer with Gradient Bingham Plastic Behaviors as a Versatile Deformable Material

We present rheological and mechanical behaviors of a partially cured photopolymer. When an ultraviolet (UV)-curable resin is exposed to UV light in atmospheric conditions, a partially cured layer is formed on the top of the resin owing to inhibitory effects of oxygen. Interestingly, such a partially cured resin behaves like a Bingham plastic with a yield stress, being a rigid solid at low shear stress and a viscous liquid at high stress. Unlike typical Bingham plastic materials, however, deformation rate saturation is observed with an increase in applied stress, which is attributed to the gradient in the degree of photopolymerization of the resin (termed "gradient Bingham plastic"). This gradient Bingham plastic can be utilized for the robust fabrication of diverse 3D, multiscale structures.

Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone

The ion concentration polarization (ICP) phenomenon is one of the most prevailing methods to preconcentrate low-abundance biological samples. The ICP induces a noninvasive region for charged biomolecules (i.e., the ion depletion zone), and targets can be preconcentrated on this region boundary. Despite the high preconcentration performances with ICP, it is difficult to find the operating conditions of non-propagating ion depletion zones. To overcome this narrow operating window, we recently developed a new platform for spatiotemporally fixed preconcentration. Unlike preceding methods that only use ion depletion, this platform also uses the opposite polarity of the ICP (i.e., ion enrichment) to stop the propagation of the ion depletion zone. By confronting the enrichment zone with the depletion zone, the two zones merge together and stop. In this paper, we describe a detailed experimental protocol to build this spatiotemporally defined ICP platform and characterize the preconcentration dynamics of the new platform by comparing them with those of the conventional device. Qualitative ion concentration profiles and current-time responses successfully capture the different dynamics between the merged ICP and the stand-alone ICP. In contrast to the conventional one that can fix the preconcentration location at only ~5 V, the new platform can produce a target-condensed plug at a specific location in the broad ranges of operating conditions: voltage (0.5-100 V), ionic strength (1-100 mM), and pH (3.7-10.3).

Nanopore Sensing in Aqueous Two-Phase System: Simultaneous Enhancement of Signal and Translocation Time via Conformal Coating

Nanofluidic resistive pulse sensing (RPS) has been extensively used to measure the size, concentration, and surface charge of nanoparticles in electrically conducting solutions. Although various methods have been explored for improving detection performances, intrinsic problems including the extremely low particle-to-pore volume ratio (<0.01%) and fast nanoparticle translocation (10-1000 µs) still induce difficulties in detection, such as low signal magnitudes and short translocation times. Herein, we present an aqueous two-phase system (ATPS) in a nanofluidic RPS for amplifying translocation signals and decreasing translocation speeds simultaneously. Two immiscible aqueous liquids build a liquid-liquid interface inside nanopores. As particles translocate from a high-affinity liquid phase into a lower-affinity one, the high-affinity liquid forms a conformal coating on the particles, which increases the effective particle size and amplifies the current-blockage signal. The translocation time is also increased, as the ATPS interface impedes the particle translocation. For 20 nm particles, 7.92-fold and 5.82-fold enhancements of signal magnitude and translocation time can be achieved. To our knowledge, this is the first attempt to improve nanofluidic RPS by treating an interface of solution reservoirs for manipulating target particles rather than nanopores. This direct particle manipulation allows us to solve the two intrinsic problems all at once.

Purification of High Salinity Brine by Multi-Stage Ion Concentration Polarization Desalination

There is an increasing need for the desalination of high concentration brine (>TDS 35,000 ppm) efficiently and economically, either for the treatment of produced water from shale gas/oil development, or minimizing the environmental impact of brine from existing desalination plants. Yet, reverse osmosis (RO), which is the most widely used for desalination currently, is not practical for brine desalination. This paper demonstrates technical and economic feasibility of ICP (Ion Concentration Polarization) electrical desalination for the high saline water treatment, by adopting multi-stage operation with better energy efficiency. Optimized multi-staging configurations, dependent on the brine salinity values, can be designed based on experimental and numerical analysis. Such an optimization aims at achieving not just the energy efficiency but also (membrane) area efficiency, lowering the true cost of brine treatment. ICP electrical desalination is shown here to treat brine salinity up to 100,000 ppm of Total Dissolved Solids (TDS) with flexible salt rejection rate up to 70% which is promising in a various application treating brine waste. We also demonstrate that ICP desalination has advantage of removing both salts and diverse suspended solids simultaneously, and less susceptibility to membrane fouling/scaling, which is a significant challenge in the membrane processes.

Microfluidic paper-based biomolecule preconcentrator based on ion concentration polarization

Microfluidic paper-based analytical devices (μPADs) for molecular detection have great potential in the field of point-of-care diagnostics. Currently, a critical problem being faced by μPADs is improving their detection sensitivity. Various preconcentration processes have been developed, but they still have complicated structures and fabrication processes to integrate into μPADs. To address this issue, we have developed a novel paper-based preconcentrator utilizing ion concentration polarization (ICP) with minimal addition on lateral-flow paper. The cation selective membrane (i.e., Nafion) is patterned on adhesive tape, and this tape is then attached to paper-based channels. When an electric field is applied across the Nafion, ICP is initiated to preconcentrate the biomolecules in the paper channel. Departing from previous paper-based preconcentrators, we maintain steady lateral fluid flow with the separated Nafion layer; as a result, fluorescent dyes and proteins (FITC-albumin and bovine serum albumin) are continuously delivered to the preconcentration zone, achieving high preconcentration performance up to 1000-fold. In addition, we demonstrate that the Nafion-patterned tape can be integrated with various geometries (multiplexed preconcentrator) and platforms (string and polymer microfluidic channel). This work would facilitate integration of various ICP devices, including preconcentrators, pH/concentration modulators, and micro mixers, with steady lateral flows in paper-based platforms.

Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination

Chloride ion, the majority salt in nature, is ∼52% faster than sodium ion (DNa+ = 1.33, DCl- = 2.03[10(-9)m(2)s(-1)]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ∼(D- - D+)/(D- + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ∼50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

Shear flow of an electrically charged fluid by ion concentration polarization: scaling laws for electroconvective vortices

We consider electroconvective fluid flows initiated by ion concentration polarization (ICP) under pressure-driven shear flow, a scenario often found in many electrochemical devices and systems. Combining scaling analysis, experiment, and numerical modeling, we reveal unique behaviors of ICP under shear flow: a unidirectional vortex structure, its height selection, and vortex advection. Determined by both the external pressure gradient and the electric body force, the dimensionless height of the sheared electroconvective vortex is shown to scale as (ϕ(2)/U(HP))(1/3), which is a clear departure from the previous diffusion-drift model prediction. To the best of our knowledge, this is the first microscopic characterization of ion concentration polarization under shear flow, and it firmly establishes electroconvection as the mechanism for an overlimiting current in realistic, large-area ion exchange membrane systems such as electrodialysis. The new scaling law has significant implications on the optimization of electrodialysis and other electrochemical systems.

Multi-vortical flow inducing electrokinetic instability in ion concentration polarization layer

In this work, we investigated multiple vortical flows inside the ion concentration polarization (ICP) layer that forms due to a coupling of applied electric fields and the semipermeable nanoporous junction between microchannels. While only a primary vortex near perm-selective membrane is traditionally known to lead to electrokinetic instability, multiple vortexes induced by the primary vortex were found to play a major role in the electrokinetic instability. The existence of multiple vortexes was directly confirmed by experiments using particle tracers and interdigitated electrodes were used to measure the local concentration profile inside the ICP layer. At larger applied electric fields, we observed aperiodic fluid motion due to electrokinetic instabilities which develop from a coupling of applied electric fields and electrical conductivity gradients induced by the ICP. The electrokinetic instability at micro-nanofluidic interfaces is important in the development of various electro-chemical-mechanical applications such as fuel cells, bio-analytical preconcentration methods, water purification/desalination and the fundamental study of ion electromigration through nanochannels and nonporous perm-selective membranes.

UV-assisted capillary force lithography for engineering biomimetic multiscale hierarchical structures: From lotus leaf to gecko foot hairs

This feature article provides an overview of the recently developed two-step UV-assisted capillary force lithography and its application to fabricating well-defined micro/nanoscale hierarchical structures. This method utilizes an oxygen inhibition effect in the course of UV irradiation curing and a two-step moulding process, to form multiscale hierarchical or suspended nanobridge structures in a rapid and reproducible manner. After a brief description of the fabrication principles, several examples of the two-step UV-assisted moulding technique are presented. In addition, emerging applications of the multiscale hierarchical structures are briefly described.

Transdural spread of glioblastoma through the foramen ovale with presentation as a masticator space mass

Direct extension of a glioblastoma through the dura at the skull base is an uncommon occurrence. We report an unusual case of recurrent glioblastoma that spread transdurally through the foramen ovale and presented primarily as a masticator space mass. There was mandibular denervation and a relative paucity of intracranial disease.

[Intracranial physiological calcification on computed tomography (Part 2): Calcification in the choroid plexus of the lateral ventricles]

In this paper, we describe calcification in the choroid plexus of lateral ventricles with a discussion of the frequency of occurrence in categories of age, sex, and laterality, and its correlation with pineal calcification. The study was conducted on 2877 consecutive cases (1450 males and 1427 females) that had plain CT scanning. Three types of CT scanners (SCN-200, Somatom 2 and TCT-10 A) were used. This series included only calcification of the choroid plexus in the trigone of the lateral ventricles (glomus). Calcification was found in none of the cases aged under 9 years, 5.9% aged from 10 to 14 years and 17.4% aged from 15 to 19 years. The calcification rate strikingly increased with increasing age of the cases. It was 51.5% of cases between 30 and 39 years of age. After that, the increasing rate of calcification gradually decreased, however calcification was found in 74.4% of cases aged over 80 years. The calcification rate was 64.7% in our total series of cases aged over 20 years, 66.5% aged over 30 years and 70.7% aged over 50 years. The calcification rate of male cases was greater than that of females in the age group of over 15 years. However, there was a significant difference only in the cases ranging from 60 to 79 years of age. The initial incidence of male cases was found at the age of 12 years and that of females at the age of 16 years. There was no difference in calcification on right and left sides.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intracranial physiological calcification on computed tomography (Part 1): Calcification of the pineal region]

Of intracranial physiological calcification, common calcification of pineal region, choroid plexus of lateral ventricles and of basal ganglia was examined based on the frequency of occurrence of age and sex and type of CT scanners. Consecutive cases of 2877 (1450 males and 1427 females) underwent plain CT scanning were studied. Pathological calcification was excluded from this study. Three types of CT scanners (SCN-200, Somatom 2 and TCT-10 A) were used. As a whole, calcification was shown in 67.7% in pineal region, 57.6% in choroid plexus of lateral ventricles and 7.5% in basal ganglia. First, we reported in detail the calcification of pineal region, in which calcification occurred most frequently. Calcification in pineal region had a close relation with age by increasing with aging. The youngest patient was 8 years old. There was a striking increase in number of patients aged from 10 to 39 years. There was a gradual increase in those aged over 40 years. Of patients aged from 70 to 79 years, calcification was found in 81.5%. The incidence was noted no changes in patients aged over 80 years. As for patients aged over 20 years, calcification was observed in 75.1% (82.6% males and 68.0% females). In patients aged from 20 to 79 years, the calcification was significantly higher in male than female. Although there was a different incidence of calcification examined by three types of CT scanners, it was not significant. There was no significant difference between thickness of 8 mm section and 10 mm.

[Effect of septal lesions on the hippocampal EEG and behavior during DRL learning in the rabbit]

We had reported that hippocampal high frequent activity at 8-10 Hz (alpha-burst) appeared during approach and lever press with the progress of DRL learning. In this study, effect of bilateral septal lesions on hippocampal EEG (especially on alpha-burst) and behavior during 10 second DRL learning was investigated in thirteen rabbits. Using the atlas of Sawyer et al., bipolar electrodes were implanted chronically in bilateral septum at coordinates of A 1-2, L 1 and D 10-11 and dorsal hippocampus at P 3-5, L 4-6 and D 7-8. Septal lesion was made by using 8-mA DC currents for 15-50-sec period enough to abolish hippocampal theta activity. DRL learning was performed after septal lesions in five rabbits. In this group, acquisition of learning was disturbed and rhythmic slow activity of the hippocampus was markedly reduced. However, movement itself was not disturbed. Although hippocampal activity recovered gradually with the progress of session, alpha-burst was not observed by the 70th session. In eight rabbits, septal lesions were made after completion of DRL learning which required 40-50 sessions. In this group, the preservation of DRL learning was disturbed and relearning was not completed by the 30th session after septal lesions. Hippocampal rhythmic activity was remarkably reduced and alpha-burst was disappeared. But, voluntary movement itself was not altered. There are several theories concerning with hippocampal rhythmic slow activity. Some author emphasized that hippocampal rhythmic activity appeared at the time of voluntary movement and it had close relation to voluntary movement.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aplasia of the posterior arch of the atlas--report on two cases]

Two cases of aplasia of the posterior arch of the atlas incidentally found are reported. Case 1: A 37-year-old man hit the forehead and the right mandible against the front glass at a head-on collision of his car and was brought to the emergency room. He was alert and neurologically normal except for multiple incision wounds with glass fragments in the face. CT, and cervical X-rays revealed total absence of the posterior arch of the atlas. Case 2: A 73-year-old woman, who sustained whip lash injury at an automobile accident, was admitted several hours after injury, complaining of neck and occipital pain. No neurological deficit was seen. CT demonstrated hemi-aplasia of the posterior arch of the atlas and isolated rudimentary posterior tubercle. Review of the literature and discussions were made on the incidence and genesis of this anomaly.

Anterior osteophytectomy for cervical spondylotic myelopathy in developmentally narrow canal

The authors present 19 cases of cervical spondylotic myelopathy in patients with developmentally narrow canal treated by microsurgical anterior osteophytectomy with interbody fusion, with follow-up periods of 1 to 8 years (mean 38 months). Postoperatively, the lower limb function, evaluated by Nurick's six-grade classification, improved two or three grades in 16 cases, one grade in two cases, and remained unchanged in one case. The upper limb function, evaluated by the authors' own four-grade classification, improved two or three grades in 11 cases, one grade in seven cases, and remained unchanged in one case. No deterioration caused by the osteophytectomy was seen. During the follow-up period, spondylolisthesis appeared 31 months postoperatively in one patient and soft disc hernia occurred 66 months postoperatively in another; these two patients were treated by a second operation and cervical traction, respectively. The authors conclude that anterior osteophytectomy with interbody fusion is applicable as a surgical treatment of cervical spondylotic myelopathy even where developmental canal stenosis is present.

[A case report of intracerebral tuberculoma during antituberculous therapy]

A case of multiple intracerebral tuberculoma occurred in the course of anti-tuberculous therapy is reported. A 16-year-old high school boy had been treated with isoniagid, streptomycin and paramino-salicylic acid on the tuberculous pleulitis for 3 months previously. He was admitted to our hospital because of progressive headache associated with vomiting. Neurological examination revealed bilateral full papilledema and incomplete bilateral abducens palsy. An immediate CT study with contrast enhancement demonstrated two small ring-like mass with considerable perifocal edema in the left temporal and occipital lobe, respectively. Intracerebral tuberculoma was considered to be most likely, so the patient was given antituberculous therapy with steroid and mannitol. However, despite of medical decompression, he developed intracranial hypertension aggravated, leading to removal of tumor 7 days after admission. Initially left temporal tuberculoma, which had more extensive and prominent perifocal edema, was successfully excised. The specimen was a walnut-sized granuloma with hard capsule including pus inside. Numerous tuberculous bacilli were identified with Ziel-Nielsen staining technique from the pus. Postoperative course was gratifying, and other tumor in the left occipital lobe, which was also diagnosed as tuberculoma, was treated with continuing administration of isoniagid, ethanbutol and rifampicin. However, the former two drugs were forced to be discontinued because of agranulocytosis. Only rifampicin was maintained for 2 months thereafter but no decrease of the size was observed in serial CT studies. Then left occipital tuberculoma was removed. The pathology was tuberculoma with positive bacilli staining. He discharged 1 month later without any neurological deficit but was on antituberculous therapy (rifampisin) as an outpatient for 3 years.(ABSTRACT TRUNCATED AT 250 WORDS)

[Trigeminal neurinoma presenting abducens nerve palsy as initial symptom: a report of two cases]

Two cases of trigeminal neurinoma presenting abducens nerve palsy as initial symptom are reported. Case 1. A 33-year-old female was admitted because of double vision of two months duration. Neurological examination revealed left abducens nerve palsy. CT scan disclosed a left parasellar tumor with a homogeneous enhancement effect. The tumor was subtotally resected by left extradural subtemporal approach, and diagnosed as trigeminal neurinoma. Case 2. A 18-year-old female was admitted because of double vision of one month duration. Neurological examination revealed left mydriasis and left abducens nerve palsy. CT scan disclosed a low density mass in the left cerebellopontine angle region and enhanced parasellar mass. The cystic mass located at the posterior fossa was removed by left retromastoid suboccipital approach, and diagnosed as trigeminal neurinoma. In these two cases, the abducens nerve palsy disappeared within two months postoperatively. The trigeminal neurinoma presenting abducens nerve palsy as initial symptoms is rare. We were able to collect six similar cases from the literature. All of them, including present two cases, were classified as ganglion type. It was suspected that the abducens nerve was compressed by the trigeminal neurinoma at the cavernous sinus, the petrous apex or the posterior fossa.

[Risk factors of cerebral aneurysm re-rupture during angiography]

Although re-rupture of cerebral aneurysm during angiography has been reported occasionally, we have encountered 13 such patients during eight years since 1974, the incidence corresponding to 4.4 percent of 295 consecutive aneurysm patients on whom a total of 467 angiographies were performed. Extravasation on angiogram was noticed in 10 of these patients. We carefully analyzed the following factors to determine which one is significantly related to aneurysm re-rupture during cerebral angiography. The factors we investigated were sex, age, sites of ruptured aneurysm, surgical risk grade and time interval between the latest rupture of aneurysm and angiography. Our procedures of angiography were standardized as such that contrast material was injected by means of power injector and the injection pressure was adjusted at 2.5 kg/cm2 in vertebral angiography, 3 kg/cm2 in carotid angiography and 4 kg/cm2 in retrograde brachial angiography. Volume of contrast material was 6-8 ml, 10-12 ml and 30-32 ml, respectively. An incidence of re-rupture during angiography when performed within the initial 24 hours after the latest bleeding episode was 12 out of 123 angiographies (9.8%), whereas 1 out of 344 angiographies (0.3%) which were performed later than 24 hours. This difference was significant (p less than 0.001). These data were further analyzed every one hour period. It was learned that re-rupture rate was significantly high, 9 out of 45 patients (20.0%) when angiography was done within 5 hours after the latest aneurysm rupture (p less than 0.01), particularly, 8 out of 27 patients (29.6%) within 3 hours (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of moyamoya disease associated with a peripheral artery aneurysm of the thalamus]

The authors report a case of moyamoya disease associated with a peripheral artery aneurysm in the thalamus of a 54-year-old woman. Plain CT scans revealed the right thalamic hemorrhage with ventricular penetration. Cerebral angiography demonstrated the characteristic appearance of moyamoya disease with a peripheral artery aneurysm in the territory of the right medial posterior choroidal artery. This aneurysm ruptured three times during 8 days since onset and the thalamic hemorrhage became larger on each occasion. Although the clinical symptoms and signs and plain CT scans disclosed thalamic hemorrhage, it was difficult to explain the cause of the hemorrhage. The authors emphasize that cerebral angiography and enhanced CT scans are quite necessary to clarify the genesis of cerebrovascular disease.

[A case report of post-traumatic syringomyelia]

A case of posttraumatic syringomyelia which appeared 26 years after the injury was presented. A patient was 61 year old female, who sustained thoraco-lumbar spine injuries rendering her to paraplegic in 1954. Eleven months later she had an operation of T6-T9 and L1-L2 laminectomies and regained motor and sensory functions of the both lower extremities. She was ambulatory with crutches till 1979. In 1980, burning pain was noticed in the left scapular region, and thereafter, extended to the ulnar side of the left forearm. The pain became progressively worse and intractable. Analgesics were ineffective. Two years later muscle atrophies and weakness in the left finger intrinsic muscles appeared. Absent deep tendon reflexes in the left upper extremity, dissociated sensory loss (in the left C2-S1 and right T5-T12 dermatomes) and paraparesis were also documented. Metrizamide CT scan performed 24 hours after the intrathecal injection disclosed an intramedullary syrinx between C2 and L1 vertebral levels. No communication with the fourth ventricle was seen. A syringoperitoneal shunt with low pressure valve was placed. The pain subsided immediately after this procedure. However, no improvement in motor and sensory functions were observed. Pathophysiological mechanisms involved in post-traumatic syrinx formation and its development were discussed. We prefer hypothesis proposed by Ball and Dayan to Gardner's hydrodynamic theory regarding to development of the syrinx secondary to spinal cord injury.

A microsurgical anterior osteophytectomy for cervical spondylotic myelopathy

Cervical spondylotic myelopathy was treated by a microsurgical anterior approach removing osteophytes completely. Follow-up results of 43 patients showed that 39 patients (91%) exhibited overall improvements of either 1, 2, or 3 grades on Nurick's grading. Four (9%) remained unchanged. Even severely affected myelopathic patients exhibited neurologic recovery. Cases that also had narrow cervical canals were treated by the same anterior osteophytectomy, and they showed similar responses. Six out of ten patients who had osteophytectomies without fusion developed neck and arm pain postoperatively, although the presence or absence of an interbody fusion did not affect the postoperative recovery from myelopathy.