Root colonization by the endophytic fungus Piriformospora indica shortens the juvenile phase of Piper nigrum L. by fine tuning the floral promotion pathways

Piriformospora indica, the mutualistic biotrophic root colonizing endosymbiotic fungus belonging to the order Sebacinales, offers host plants various benefits and enhances its growth and performance. The effect of colonization of P. indica in Piper nigrum L. cv. Panniyur1 on growth advantages, floral induction and evocation was investigated. Growth and yield benefits are credited to the alteration in the phytohormone levels fine-tuned by plants in response to the fungal colonization and perpetuation. The remarkable upregulation in the phytohormone levels, as estimated by LC- MS/MS and quantified by qRT-PCR, revealed the effectual contribution by the endophyte. qRT-PCR results revealed a significant shift in the expression of putative flowering regulatory genes in the photoperiod induction pathway (FLOWERING LOCUS T, LEAFY, APETALA1, AGAMOUS, SUPPRESSOR OF CONSTANS 1, GIGANTEA, PHYTOCHROMEA, and CRYPTOCHROME1) gibberellin biosynthetic pathway genes (GIBBERELLIN 20-OXIDASE2, GIBBERELLIN 2-OXIDASE, DELLA PROTEIN REPRESSOR OF GA1-3 1) autonomous (FLOWERING LOCUS C, FLOWERING LOCUS VE, FLOWERING LOCUS CA), and age pathway (SQUAMOSA PROMOTER LIKE9, APETALA2). The endophytic colonization had no effect on vernalization (FLOWERING LOCUS C) or biotic stress pathways (SALICYLIC ACID INDUCTION DEFICIENT 2, WRKY family transcription factor 22). The data suggest that P. nigrum responds positively to P. indica colonization, affecting preponement in floral induction as well as evocation, and thereby shortening the juvenile phase of the crop.

Primary Intracranial Spindle Cell Sarcoma, DICER1-Mutant, with MDM2 Amplification Diagnosed on the Basis of Extensive Molecular Profiling

Primary intracranial spindle cell sarcoma is an extremely rare mesenchymal tumor, the molecular pathogenesis of which is poorly understood. Because of the lack of specific markers, diagnosis sometimes relies on ruling out all possible differential diagnoses, often making it difficult to reach a definitive diagnosis. In this case study, we report a 69 year-old female patient for whom the integration of multi-layered molecular analyses contributed to making the diagnosis. The disease exhibited aggressive clinical behavior, requiring two sequential surgeries because of rapid regrowth within a short period. Primary and recurrent tumors exhibited similar histological features, in which spindle-shaped cells arranged in interlacing fascicles without any specific architectures, implicating sarcomatous tumors. In immunohistochemistry testing, tumor cells were immunopositive for vimentin but lacked any specific findings that contribute to narrowing down the differential diagnoses. Seeking further diagnostic clues, we performed DNA methylation-based analysis. The copy number analysis revealed MDM2 gene amplification and loss of heterozygosity of 22q. Moreover, dimension reduction clustering analysis implicated a methylation pattern comparable to aggressive types of sarcomas. In addition, an in-house next-generation sequencing panel ("Todai-OncoPanel") analysis identified somatic mutations in DICER1, NF2, and ATRX genes. Taken all together, we finally made the diagnosis of primary intracranial spindle cell sarcoma, DICER1-mutant, with MDM2 gene amplification. This case report suggests that even for the tumors with insufficient morphological and immuno-histological diagnostic clues, integration of multi-layered molecular analyses can contribute to making the diagnoses as well as to understanding the rare tumors by elucidating unexpected genetic and epigenetic features.

[Malignant Transformation of Cerebellopontine Angle Epidermoid Cyst:A Case Report]

Intracranial epidermoid cysts are benign cystic lesions that typically exhibit slow growth. Their malignant transformation into squamous cell carcinoma is rare. We report a 77-year-old woman who was admitted to our hospital because of a near-drowning incident due to a seizure sustained in her bathtub. Magnetic resonance imaging(MRI)revealed an extra-axial tumor occupying the right cerebellopontine angle. The lesion appeared hyperintense in diffusion-weighted images and exhibited contrast enhancement after gadolinium injection. Cerebrospinal fluid examination revealed noninfectious meningitis, presumably due to the ruptured epidermoid cyst. Tumor resection was performed and histopathological examination revealed squamous cell carcinoma, which was indicative of malignant transformation of the cyst. The patient underwent adjuvant radiotherapy and has no signs of recurrence 9 months postsurgery. Rapid neurological deterioration and contrast enhancement on MRI are key signs of malignant transformation of epidermoid cysts.

Resection of a lateral supratentorial endodermal cyst complicated by postoperative seizures: A case report

Background:

Endodermal cysts are uncommon cystic lesions usually located at the ventral aspects of the spine. A lateral supratentorial location of such cysts is extremely rare. A unique case of a lateral supratentorial endodermal cyst that required surgical intervention due to uncal herniation, complicated with postoperative seizures, is presented.

Case Description:

A 48-year-old man presented with transient motor aphasia and diplopia. Magnetic resonance imaging showed a cystic lesion occupying the left frontal and temporal convexity with midline shift and uncal herniation. Cyst resection was performed, and cyst contents with mucous-like components were aspirated. Histopathological examination showed an endodermal cyst. The patient showed no neurological deficits immediately after surgery but developed tonic-clonic seizures 9 h after surgery. Sedation and intubation were required to control the seizures. After administering multiple antiepileptic drugs, he was extubated on the 5^th day after surgery. He was discharged home in a month with mild impairment in dexterity of his right hand.

Conclusions:

Surgical intervention for endodermal cysts can be complicated by postoperative seizures caused by chemical irritation of brain cortex due to spillage of cyst contents. It is important to irrigate the cyst wall very well intraoperatively and pay attention not to spill the cyst fluid to unaffected locations. Preoperative administration of antiepileptic drugs should also be considered if endodermal cysts, not simple arachnoid cysts, are suspected preoperatively.

Anterior interhemispheric approach for clipping of subcallosal distal anterior cerebral artery aneurysms: case series and technical notes

Distal anterior cerebral artery (DACA) aneurysms are rare, accounting for 1-9% of all intracranial aneurysms. Previous systematic reviews have highlighted that given the markedly increased incidence of major complications after endovascular treatment, microsurgical clipping is the more attractive treatment option with generally excellent clinical outcomes. Subcallosal DACA aneurysms constitute a rare subset of these aneurysms, requiring special anatomic considerations-particularly with regard to the approach. The aim of this study is to review the technical nuances of microsurgical treatment of subcallosal DACA aneurysms, including review of contemporary techniques through presentation of a microneurosurgical operative video. This is a retrospective case series and intraoperative microsurgical videos review. Three subcallosal DACA aneurysms were identified via retrospective query of our institutional neurosurgical database from December 2017 to May 2018. Two were female; median age was 74 years (range 70-83); all 3 underwent bifrontal craniotomy via bicoronal skin incision for aneurysm clipping. Aneurysms were located in left pericallosal-callosomarginal artery junction, bifurcation of azygos A2, and pericallosal artery related with azygos A2, and the anterior interhemispheric approach was used in all 3 operations. No acute stroke, hemorrhage, or major complications occurred, and all patients remained neurologically intact at the time of last follow-up (median 3 months, range 1-6). Although DACA aneurysms are rare, they represent an important variant for cerebrovascular neurosurgeons where microsurgical clipping can have better angiographic outcomes than endovascular treatment. Detail-oriented anterior interhemispheric arachnoid dissection through bifrontal craniotomy with its lower margin sitting at the superior orbital rim maximizes safe and effective clipping of subcallosal DACA aneurysms.

Intramedullary and intratumoral hemorrhage in spinal hemangioblastoma: Case report and review of literature

Background:

Intramedullary hemorrhages involving spinal hemangioblastomas are rare. They are frequently associated with devastating neurologic outcomes, despite with emergent surgical intervention. Here, we presented an example of an intramedullary hemorrhage occurring in a spinal hemangioblastoma, where the patient markedly improved with surgery. Additionally, the appropriate literature was reviewed (including intraoperative video).

Case Description:

A 49-year-old female with a 4-year history of tingling in the left lower extremity presented with vomiting, stepwise worsening of bilateral scapular pain, new upper motor neuron signs, and severe sensory loss bilaterally below C4 on the left and T4 on the right. The magnetic resonance imaging demonstrated a well-circumscribed, uniformly enhancing intramedullary tumor at the C2 level with hyperintensity on the T2 study consistent with acute hemorrhage and cord edema. An urgent C2 laminectomy was performed for gross total tumor resection. Intraoperatively, intramedullary hemorrhage was identified anterior to the tumor mass and was confirmed histopathologically. Postoperatively, the patient had no new sensorimotor deficits and fully recovered within two postoperative months.

Conclusions:

Patients presenting with acute intramedullary hemorrhage within hemangioblastomas of the spinal cord may demonstrate significant postoperative neurological recovery.

The Method for Placement of an Intraoperative Continuous Facial Nerve Stimulating Electrode in Acoustic Neuroma Surgery: Technical Note

Preservation of facial nerve (FN) function is the most important goal in acoustic neuroma (AN) surgery. We have been using intraoperative continuous facial nerve monitoring (ICFNm) of evoked electromyography during AN surgery. ICFNm is very useful, and we can identify the real-time functions of the FN. Some surgeons have experienced difficulty with placing the ICFN stimulating electrode (SE). We therefore show how to place the ICFN SE. We mostly perform AN surgery with a retrosigmoid approach (RSA). A craniotomy with four burr holes is performed. We dissect the arachnoid membrane along the accessory nerve from the cisterna magna to the glossopharyngeal nerve. When we are able to identify the root exit zone (REZ) of the FN near the brainstem, we place the ICFN SE on it. However, when a large tumor covers the REZ, we have to debulk the tumor to create a space between the tumor and the glossopharyngeal nerve. After that, we can place the SE on the REZ. A method for placement of the ICFN SE is needed for some techniques of AN surgery. Once we learn how to place the SE, we can identify continuous FN function during AN surgery. This method is useful for the preservation of postoperative FN function in AN surgery.

Hypervascular Vestibular Schwannomas: Clinical Characteristics, Angiographical Classification, and Surgical Considerations

BACKGROUND

There is a rare type of vestibular schwannoma, scarcely discussed in the literature, known as a hypervascular vestibular schwannoma (HVS).

OBJECTIVE

To evaluate its biological characteristics, angiographical classification, surgical outcomes, and the significance for surgical consideration, using a large series of this clinical entity.

METHODS

The definition for HVS in this study was the tumor stain from the vertebrobasilar system (VBS) in angiography. The authors conducted a retrospective analysis of 36 patients who were angiographically diagnosed with HVS and underwent surgery between 2008 and 2015. Their biological findings and their surgical outcomes were compared with non-HVS subjects. With regard to the tumor feeders and AV shunt, we classified HVS into 5 types.

RESULTS

HVS occurred more commonly in younger subjects (mean: 39.4 yr), as a larger solid tumor with multiple flow voids (mean: 34.1 mm), and involved higher levels of cerebrospinal fluid protein (mean: 202 mg/dl) and a higher MIB1-index (mean: 4.3%). The average resection rate for these 36 cases was 95.3%, and recurrence was seen in 6 cases (16.7%). Compared with non-HVS, the extent of tumor resection was significantly lower, and the recurrence rate was significantly higher. Especially in HVS type 2B (the tumor stain is fed by the VBS and the external carotid artery, with an arteriovenous shunt from the VBS), the recurrence-free survival duration was significantly shorter compared with other HVS types and non-HVS, and HVS type 2B exhibited an identifiable risk factor for recurrence.

CONCLUSION

HVS have the distinct clinical characteristics compared with those of non-HVS subjects.

Intelligent control of neurosurgical robot MM-3 using dynamic motion scaling

OBJECTIVE

Advanced and intelligent robotic control is necessary for neurosurgical robots, which require great accuracy and precision. In this article, the authors propose methods for dynamically and automatically controlling the motion-scaling ratio of a master-slave neurosurgical robotic system to reduce the task completion time.

METHODS

Three dynamic motion-scaling modes were proposed and compared with the conventional fixed motion-scaling mode. These 3 modes were defined as follows: 1) the distance between a target point and the tip of the slave manipulator, 2) the distance between the tips of the slave manipulators, and 3) the velocity of the master manipulator. Five test subjects, 2 of whom were neurosurgeons, sutured 0.3-mm artificial blood vessels using the MM-3 neurosurgical robot in each mode.

RESULTS

The task time, total path length, and helpfulness score were evaluated. Although no statistically significant differences were observed, the mode using the distance between the tips of the slave manipulators improves the suturing performance.

CONCLUSIONS

Dynamic motion scaling has great potential for the intelligent and accurate control of neurosurgical robots.

[An Endovascular Approach for Ruptured Aneurysms of the Basilar Trunk Perforating Artery]

Aneurysms of the basilar trunk perforating artery are rarely described in the literature. Only 13 cases have been reported previously. The recommended treatment for these aneurysms is usually direct surgery such as microsurgical clipping or proximal trapping;endovascular therapy is not preferred because of difficulty to access the aneurysm. Recently however, a case report of treatment of basilar trunk perforating aneurysm with a Pipeline Embolization Device was published. Microsurgical clipping or wrapping has the disadvantage of the deep and narrow operative area and the difficult skull-base technique. Here, we report a case of basilar trunk perforating rupture aneurysm and its treatment with endovascular coil embolization.

Cavernous sinus angioleiomyoma: case report and review of the literature

Cavernous sinus angioleiomyoma (ALM) is extremely rare. Only three cases have been reported to be cavernous sinus ALM, and very few reports described characteristic findings for intracranial ALMs in detail. We report a new case of cavernous sinus ALM, with detailed information on the clinical presentation, radiology, pathology, and surgical approach. A 52-year-old woman had a 6-month history of right eye discomfort. Magnetic resonance imaging showed a right cavernous sinus tumor with heterogenous blush enhancement. Enhanced computed tomography scans and angiography showed small nodular enhancement in the tumor. Complete tumor resection was achieved via an extradural temporopolar approach. ALM was identified based on histologic examination. Intracranial ALMs are different from the ALMs that occur in the extremities based on our review of the literature. Intracranial ALMs appear more frequently in men than women. The cavernous type was the most common pathologically, and they occur often in the epiperidural location. Because cavernous sinus ALM occurs in the interdural space, an epidural approach should be selected. Therefore, it is important to include cavernous sinus ALM into a differential diagnosis of a cavernous sinus tumor. The blush enhancement and nodular enhancement within this lesion may be useful to distinguish cavernous sinus ALM from other differential diagnoses.

Perioperative management of catecholamine-secreting glomus jugulare tumors

To treat patients with a catecholamine-secreting glomus jugulare tumor, perioperative management is important. Perioperative catecholamine hypersecretion causes severe problems in the treatment of a catecholamine-secreting glomus tumor. Therefore, a precise therapeutic strategy and perioperative management are required through collaboration of the endocrinology, anesthesiology, and endocrine surgery departments . We describe our perioperative management for catecholamine-secreting glomus jugulare tumor. The patient was a 31-year-old woman with a 50-mm glomus jugulare tumor and a significantly elevated plasma noradrenaline level of 21,165 pg/ml. Before the surgery, oral α − blocker administration was initiated for ∼ 3 months, and her body weight increased from 52 kg at the time of examination to 54.2 kg. Coil embolization of the tumor vessel was performed 1 week before surgery, and the intense tumor stain was reduced by 90%. The patient underwent almost total removal of the tumor via mastoidectomy with high cervical exposure via the transsigmoid approach. Postoperatively, plasma noradrenaline decreased markedly. Preoperative pharmacologic stabilization and peri- and postoperative anesthetic management are essential for the treatment of a catecholamine-secreting glomus jugulare tumor.

Development of a new compact intraoperative magnetic resonance imaging system: concept and initial experience

BACKGROUND

Magnetic resonance imaging (MRI) during surgery has been shown to improve surgical outcomes, but the current intraoperative MRI systems are too large to install in standard operating suites. Although 1 compact system is available, its imaging quality is not ideal.

OBJECTIVE

We developed a new compact intraoperative MRI system and evaluated its use for safety and efficacy.

METHODS

This new system has a magnetic gantry: a permanent magnet of 0.23 T and an interpolar distance of 32 cm. The gantry system weighs 2.8 tons and the 5-G line is within the circle of 2.6 m. We created a new field-of-view head coil and a canopy-style radiofrequency shield for this system. A clinical trial was initiated, and the system has been used in 44 patients.

RESULTS

This system is significantly smaller than previous intraoperative MRI systems. High-quality T2 images could discriminate tumor from normal brain tissue and identify anatomic landmarks for accurate surgery. The average imaging time was 45.5 minutes, and no clinical complications or MRI system failures occurred. Floating organisms or particles were minimal (1/200 L maximum).

CONCLUSION

This intraoperative, compact, low-magnetic-field MRI system can be installed in standard operating suites to provide relatively high-quality images without sacrificing safety. We believe that such a system facilitates the introduction of the intraoperative MRI.

Determination of the keyhole position in a lateral suboccipital retrosigmoid approach

Appropriate placement of the keyhole at the transverse and sigmoid sinus (T/S) junction is important for performance of safe and accurate lateral suboccipital craniotomy with minimum bone loss. Here, we report a method for predicting the position of the T/S junction and investigate the relationship between the T/S junction and asterion. The subjects were 88 patients treated surgically via a lateral suboccipital approach. These cases included 78 acoustic neuromas, 4 meningiomas, 1 trigeminal schwannoma, 1 epidermoid cyst, 2 trigeminal neuralgias, and 1 hemifacial spasm. To expose the T/S junction, we usually place the keyhole lateral to asterion by a half diameter of the burr hole. The distance of the T/S junction from asterion was investigated using three-dimensional computed tomography (3DCT) images. We investigated the differences between the actual and predicted positions of the T/S junction based on skull landmarks, and we compared our method with other literature methods. The mean distances were 5.7 mm caudal and 6.6 mm lateral. The difference between the actual and predicted positions was significantly smaller in our approach compared to other methods. Placing the keyhole lateral to a provisional burr hole just caudal to asterion and lateral by half the diameter of the burr hole was useful for exposure of the T/S junction. The best approach is to use preoperative 3DCT, but this may be limited by equipment problems, emergency cases, or allergy to contrast medium. Determination of the appropriate keyhole position with reference to skull landmarks is a universally useful method.

Hydrocephalus associated with vestibular schwannomas: perioperative changes in cerebrospinal fluid

BACKGROUND

Cerebrospinal fluid (CSF) protein levels are known to increase in patients with vestibular schwannomas (VS) with concomitant hydrocephalus, however the only information available on perioperative changes in CSF in these patients comes from case reports. Here, we investigated the relation between CSF protein and hydrocephalus in a large series of patients undergoing resection of VS.

METHOD

We classified 376 patients undergoing resection for VS at our institute into two groups, namely VS and no hydrocephalus (control, n = 319) and VS with concomitant hydrocephalus (n = 57), and compared clinical parameters. Among the 57 patients diagnosed with hydrocephalus, hydrocephalus status was examined by lumbar puncture in 20 patients with communicative hydrocephalus, and pre- and postoperative scores in CSF properties were compared.

RESULTS

Patients in the hydrocephalus group were significantly older than those in the control group (mean, 55.8 vs. 43.8 years), and had a longer disease duration (median, 76 vs. 12 months), larger tumors (median, 15.6 vs. 5.5 ml), and a higher protein concentration in CSF (median, 147.3 vs. 65.1 mg/dl). Perioperative CSF samples of hydrocephalus patients showed a significantly decrease in cerebrospinal pressure after tumor removal (median, -75mmH2O), followed by a decrease in CSF protein (median, -74.5 mg/dl). No patients required the placement of a shunt.

CONCLUSIONS

Extended disease duration and elevated CSF protein secondary to the presence of a tumor contribute to the occurrence of hydrocephalus. Primary maximal tumor removal for VS with coexisting hydrocephalus avoids an unnecessary shunt.

Master-slave robotic platform and its feasibility study for micro-neurosurgery

BACKGROUND

Microsurgery is a widely performed process in neurosurgery. However, it is difficult for surgeons because manipulating small and long instruments under a microscope often restricts dexterity. Hand tremors are also an issue, as the accuracy required for microsurgery is very high.

METHOD

A master-slave robotic platform has been developed for neurosurgery. A position-orientation decoupled design was employed to enhance positioning accuracy, and a smooth trajectory generation method was developed.

RESULT

The robotic tasks exhibited improved positioning accuracy compared to manual tasks. Anastomoses of 0.3 and 0.5 mm artificial vessels were successfully performed in end-to-end and end-to-side fashion.

CONCLUSION

With the robotic platform, the surgeon was able to perform a fine and complex task, which is very difficult with manual operation. The robotic system showed sufficient accuracy and dexterity, but with a longer task completion time. Further improvement of the dexterity and user interface is expected to realize better performance.

Preoperative evaluation of unruptured cerebral aneurysms by fast imaging employing steady-state acquisition image

BACKGROUND

In aneurysm surgery, understanding the microanatomy around the aneurysm such as perforating arteries and cranial nerves is mandatory.

OBJECTIVE

To assess the usefulness in determining the microanatomy around the cerebral aneurysms by the use of fast imaging employing steady-state acquisition (FIESTA) images of magnetic resonance imaging preoperatively, in addition to computed tomography and digital subtraction angiography.

METHODS

Between October 2006 and June 2009, 123 patients with 140 unruptured cerebral aneurysms were treated in our institution. Eighty-two patients were assessed with FIESTA by the operators on the workstation of the magnetic resonance image before surgical clipping of the aneurysms. The small vessels and cranial nerves were confirmed intraoperatively before or after obliteration of the aneurysms.

RESULTS

Sensitivities and specificities of FIESTA imaging were 100% in detecting hypothalamic artery around anterior communicating artery aneurysms, oculomotor nerve attachment to the posterior communicating artery aneurysm domes, and anterior choroidal artery adhesion to the posterior communicating artery aneurysms. This technique was also useful for predicting adhesion between the aneurysm and adjacent main trunks or perforators. Although the specificity was 100%, sensitivity was 56% in detecting vessel adhesion around the middle cerebral aneurysms. This technique can provide limited information in large aneurysms or aneurysms located in minimal cerebrospinal fluid space. The overall outcomes of the patients included 120 excellent recoveries, 1 moderate deficit, 1 severe deficit, and 1 persistent vegetative state according to the Glasgow Outcome Scale.

CONCLUSION

By giving information on the minute anatomical structure around the aneurysm, FIESTA can contribute to thorough preoperative evaluations of cerebral aneurysms.

Intraoperative continuous monitoring of evoked facial nerve electromyograms in acoustic neuroma surgery

BACKGROUND

Preservation of facial nerve function is one of the most important goals in acoustic neuroma surgery. We have been using intraoperative continuous monitoring of evoked facial nerve electromyograms (EMGs) since 1997 in acoustic neuroma surgery. We therefore investigated surgically treated patients to clarify the usefulness of this monitoring, and to determine safety criteria for preserving facial nerve function.

METHODS

This intraoperative continuous monitoring of evoked facial nerve EMG is a method for checking the EMG evoked by continuous direct electrical stimulation of the facial nerve during tumor excision. The greatest advantage of this method is the ability to identify changes in EMG in real time. We retrospectively investigated 216 patients with surgically treated acoustic neuroma to identify correlations between parameters in this monitoring and postoperative facial nerve function immediately and 1 year after surgery.

RESULTS

In these patients, the functional preservation rate of the facial nerve (House and Brackmann grade 1 or 2 at 1 year after surgery) was 98.6% with a 98.2% mean tumor resection rate. Amplitude preservation ratio correlated significantly with facial nerve function both immediately and 1 year after surgery. To avoid severe facial nerve palsy, a warning criterion of amplitude preservation ratio >50% appears useful.

CONCLUSIONS

Postoperative course of facial nerve function appears predictable using intraoperative continuous monitoring of evoked facial nerve EMGs. This monitoring is useful to increase the tumor excision rate while avoiding severe postoperative facial nerve palsy in acoustic neuroma surgery.

Is an Acoustic Neuroma an Epiarachnoid or Subarachnoid Tumor?

BACKGROUND:

There are arguments about whether acoustic neuromas are epiarachnoid or subarachnoid tumors.

OBJECTIVE:

To retrospectively examine 118 consecutively operated-on patients with acoustic neuromas to clarify this point.

METHODS:

Epiarachnoid tumors are defined by the absence of an arachnoid membrane on the tumor surface after moving the arachnoid fold (double layers of the arachnoid membrane) toward the brainstem. In contrast, subarachnoid tumors are characterized by the arachnoid membrane remaining on the tumor surface after moving the arachnoid fold. Based on this hypothesis, we used intraoperative views and light and electron microscopy to confirm the existence of an arachnoid membrane after the arachnoid fold had been moved.

RESULTS:

The tumors were clearly judged to be subarachnoid tumors in 86 of 118 patients (73%), an epiarachnoid tumor in 2 patients (2%), whereas a clear judgment was difficult to make in the remaining 30 patients (25%).

CONCLUSION:

The majority of acoustic neuromas are subarachnoid tumors, with epiarachnoid tumors being considerably less common.

Microsurgical skill assessment: toward skill-based surgical robotic control

A surgical skill assessment system was developed to quantify microsurgical skills. Infrared optical makers, an inertial measurement unit, and strain gauges were mounted on tweezers to record surgical tasks. In preliminary experiments, the tool tip trajectory, acceleration, and applied force were measured and microsurgery videos were evaluated by three expert surgeons. The preliminary results indicated the feasibility of the system by showing the significant difference between unskilled and skilled surgeons.

Meiotic Diploid Progeny and Meiotic Nondisjunction in SACCHAROMYCES CEREVISIAE

Abnormalities in chromosome number that occurred during meiosis were evaluated with a specially-constructed diploid strain of Saccharomyces cerevisiae. The strain is heterozygous for six markers of the right arm of chromosome V and heterozygous for cyh2 (resistance to cycloheximide) on chromosome VII.-Selection of meiotic spores on a medium containing cycloheximide and required nutrilites-except those for the markers of the right arm of chromosome V-allows the growth of aberrant clones belonging only to two classes: a) diploid clones, caused by failure of the second meiotic division, with a frequency of 0.54 x 10(-4) per viable spore; and b) diplo V, aneuploids derived from nondisjunctions in meiosis I or meiosis II, with a total spontaneous frequency of 0.95 x 10(-4) per viable spore. About two-thirds of the aneuploids originated during meiosis I, the rest during meiosis II. An investigation of these events in control meioses and after treatment with MMS, Benomyl and Amphotericin B suggests that this assay system is suitable for screening environmental mutagens for their effects on meiotic segregation.

Simulation of and training for cerebral aneurysm clipping with 3-dimensional models

OBJECTIVE

With improvements in endovascular techniques, fewer aneurysms are treated by surgical clipping, and those aneurysms targeted for open surgery are often complex and difficult to treat. We devised a hollow, 3-dimensional (3D) model of individual cerebral aneurysms for preoperative simulation and surgical training. The methods and initial experience with this model system are presented.

METHODS

The 3D hollow aneurysm models of 3 retrospective and 8 prospective cases were made with a prototyping technique according to data from 3D computed tomographic angiograms of each patient. Commercially available titanium clips used in our routine surgery were applied, and the internal lumen was observed with an endoscope to confirm the patency of parent vessels. The actual surgery was performed later.

RESULTS

In the 8 prospective cases, the clips were applied during surgery in the same direction and configuration as in the preoperative simulation. Fine adjustments were necessary in each case, and 2 patients needed additional clips to occlude the atherosclerotic aneurysmal wall. With these 3D models, it was easy for neurosurgical trainees to grasp the vascular configuration and the concept of neck occlusion. Practicing surgery with these models also improved their handling of the instruments used during aneurysm surgery, such as clips and appliers.

CONCLUSION

Using the hollow 3D models to simulate clipping preoperatively, we could treat the aneurysms confidently during live surgery. These models allow easy and concrete recognition of the 3D configuration of aneurysms and parent vessels.

Microsurgical robotic system for the deep surgical field: development of a prototype and feasibility studies in animal and cadaveric models

Object. To enhance the surgeon's dexterity and maneuverability in the deep surgical field, the authors developed a master—slave microsurgical robotic system. This concept and the results of preliminary experiments are reported in this paper.

Methods. The system has a master control unit, which conveys motion commands in six degrees of freedom (X, Y, and Z directions; rotation; tip flexion; and grasping) to two arms. The slave manipulator has a hanging base with an additional six degrees of freedom; it holds a motorized operating unit with two manipulators (5 mm in diameter, 18 cm in length). The accuracy of the prototype in both shallow and deep surgical fields was compared with routine freehand microsurgery. Closure of a partial arteriotomy and complete end-to-end anastomosis of the carotid artery (CA) in the deep operative field were performed in 20 Wistar rats. Three routine surgical procedures were also performed in cadavers.

The accuracy of pointing with the nondominant hand in the deep surgical field was significantly improved through the use of robotics. The authors successfully closed the partial arteriotomy and completely anastomosed the rat CAs in the deep surgical field. The time needed for stitching was significantly shortened over the course of the first 10 rat experiments. The robotic instruments also moved satisfactorily in cadavers, but the manipulators still need to be smaller to fit into the narrow intracranial space.

Conclusions. Computer-controlled surgical manipulation will be an important tool for neurosurgery, and preliminary experiments involving this robotic system demonstrate its promising maneuverability.

Diagnosis of acute ischemic stroke based on time-to-peak and diffusion-weighted magnetic resonance imaging

Rapid and accurate diagnosis of the hemodynamics of the brain is essential for the treatment of acute ischemic stroke. This study investigated whether time-to-peak and diffusion-weighted magnetic resonance (MR) imaging are useful for predicting the course of stroke. Fourteen patients with non-lacunar acute ischemic stroke underwent emergent MR imaging within 24 hours from the onset followed by cerebral angiography and xenon-enhanced computed tomography (CT). Serial CT was obtained to monitor changes in the size and nature of the infarct. Volumes of the abnormal lesions demonstrated on time-to-peak (VT) or diffusion-weighted (VD) images were measured, and the ratio of VT to VD was calculated. Based on this ratio, patients were classified into three groups: Group 1 (VT/VD 0.5-1.5, n = 9), Group 2 (VT/VD > 1.5, n = 3), and Group 3 (VT/VD < 0.5, n = 2). The size of the infarct detected as a low-density area on serial CT scans did not change significantly throughout the course in Group 1 patients, but showed enlargement in all three patients in Group 2. Two patients in Group 3 had major trunk occlusion followed by spontaneous reperfusion, and both developed hemorrhagic transformation. Our study showed that classification of ischemic stroke based on the VT/VD ratio was predictive of the time course of the infarct, and may be useful in selecting the initial therapeutic procedure immediately after the onset of stroke.

Incidence of von Hippel-Lindau disease in hemangioblastoma patients: the University of Tokyo Hospital experience from 1954-1998

BACKGROUND

Incidence of von Hippel-Lindau disease among hemangioblastomas is important clinical information affecting the management of hemangioblastomas. Studies from Western countries reported 36-40% for the incidence, but no report has been made on the Japanese population.

METHOD

To investigate the incidence in Japan, we retrospectively analyzed all hemangioblastoma patients treated at The University of Tokyo Hospital from 1954 to 1998. By reviewing medical records and imaging studies, von Hippel-Lindau disease was diagnosed clinically following the currently suggested diagnostic criteria.

FINDINGS

There were 82 hemangioblastoma patients recorded during the period, and 14 cases (17%) were compatible with von Hippel-Lindau disease. However, when the incidence was calculated for each of the three 15-year periods, which are 1954-1968 (first), 1969-1984 (second), and 1985-1998 (third), the number increased dramatically in the later periods: 2 of 33 (6%) during the first, 4 of 26 (15%) during the second, and 8 of 22 (36%) during the third period. Such increase occurred after the introduction of whole body CT to our institution in 1981, suggesting that improvement of imaging techniques contributed to the sensitivity of diagnosis. In addition, one recent patient with multiple hemangioblastomas was found to harbor germline mutation of the VHL, thereby being diagnosed as von Hippel-Lindau disease on the basis of molecular genetics.

INTERPRETATION

The 40% incidence of von Hippel-Lindau disease in hemangioblastomas suggests that extensive screening for von Hippel-Lindau disease associated neoplasms, and probably molecular genetic examination, is indicated for all patients with hemangioblastomas, which should aim for earlier diagnosis and better management of this devastating hereditary disease.

[A case of sacral meningeal cyst with Marfan syndrome]

A rare case of sacral meningeal cyst Marfan syndrome is reported. A 40-year-old male who had a past history of Marfan syndrome was admitted to Tokyo Metropolitan Ebara Hospital due to sensory disturbance in the right S1-2 nerve root area on October 1998. On admission, neurological deficits were sensory disturbance and decrease right Achilles reflex. Plain sacral X-ray was normal. Magnetic resonance imaging revealed a cystic mass in the intrasacral space. MR myelography showed the cyst followed the thecal sac. Signal intensity of the cystic mass was the same as the cerebrospinal fluid. In the prone position, laminectomy of the sacrum was carried out. The neck of the meningeal cyst was ligated with the help of an aneurysmal needle. The patient's sensory disturbance disappeared postoperatively. As MRI becomes more frequently used in Marfan syndrome, it is important to keep the presence of such an entity in mind. MR myelography made it easy to diagnose the meningeal cyst.

Precocious puberty in a girl with an hCG-secreting suprasellar immature teratoma. Case report

Although precocious puberty is common in boys with human chorionic gonadotropin (hCG)-secreting brain tumors, it is extremely rare in girls. The authors describe a 6-year-old girl with an hCG-secreting suprasellar immature teratoma who presented with diabetes insipidus, increased intracranial pressure, and precocious puberty. On admission, breast budding was observed. The serum hCG level was 1230 mIU/ml. Both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) remained below detectable levels, even after gonadotropin-releasing hormone stimulation. Serum estrogen and androgen were moderately elevated. After chemotherapy, breast budding disappeared with normalization of serum hCG. It has been believed that hCG does not produce precocious puberty in girls in the absence of FSH, and this has been used as an explanation for the rarity of precocious puberty in girls with hCG-secreting brain tumors. However, it has also been reported that hCG has not only LH activity but also intrinsic, although weak, FSH-like activity. In the present case, this FSH-like activity was considered to have played a role in the development of precocious puberty. It is speculated that a very high level of serum hCG can produce precocious puberty in girls. The rarity of intracranial germ-cell tumors with a high potential of hCG secretion may be one of the reasons why hCG-induced precocious puberty is uncommon in girls.

Preparation of high molecular weight plant DNA and its use for artificial chromosome construction

The availability of a substantial amount of high molecular weight DNA is an essential prerequisite for the construction of yeast artificial chromosome (YAC) libraries. Parameters concerning protoplast isolation and DNA extraction have been systematically analyzed. Conditions have been established for the obtainment of high molecular weight DNA from Arabidopsis thaliana and Nicotiana plumbaginifolia protoplasts either embedded in agarose plugs or in liquid suspension. Restriction fragments were obtained by partial and total digestion with different endonucleases, and separated by pulsed-field gel electrophoresis. Ligation of partially EcoRI-digested DNA (range 30-300 kbp) followed by transformation of yeast spheroplasts gave rise to YACs with an average size of 60 kbp. The introduction of a DNA size-selection step before ligation led to production of YACs in the range of 100-200 kbp. Clones of up to 460 kbp were obtained by blunt-end ligation of pre-selected unrestricted DNA.

A gene tightly linked to CEN6 is important for growth of Saccharomyces cerevisiae

Transcriptional analysis of the region flanking the left boundary of the centromere of chromosome VI revealed the presence of a gene immediately adjacent to CEN6. The transcription of the gene is directed toward the centromere, and nucleotide sequence analysis showed that the coding region terminates only 50 bp away from CEN6. Our results extend to chromosome VI the observation that centromere-flanking regions of S. cerevisiae are transcriptionally active. Disruption of the coding region of the gene showed that its product, whilst not essential for cell viability, is important for normal cell growth. The gene has been termed DEG1 (DEpressed Growth rate). Comparison of the deduced amino acid sequence of DEG1 with a protein sequence databank revealed homology with the enzyme tRNA pseudouridine synthase I of E. coli.

Induction of meiotic chromosomal malsegregation in yeast

A system to detect chromosome number abnormalities occurring during meiosis in Saccharomyces cerevisiae is described. It is based on selection of spores carrying 2 multi-marked chromosomes V. Each step of the technical procedure is critically analyzed and the origin of some biases discussed. Selection and subsequent genetic analysis allow the estimation of the frequency of spontaneous and induced diploid and aneuploid n + 1 (diplo-V) spores. Data are reported concerning the effect of 53 chemical compounds. The great majority of active chemicals induce diploid clones while a minority cause non-disjunction of chromosome V.

Caffeine interactions with methyl methanesulphonate, hycanthone, benlate, and cadmium chloride in chromosomal meiotic segregation of Saccharomyces cerevisiae

Interactions of caffeine with chemicals known for their effects on chromosomal segregation during meiosis of Saccharomyces cerevisiae were studied. It appears that caffeine does interfere with the action of other compounds during the different phases of meiosis. Treatments with methyl methanesulphonate (MMS) and cadmium chloride (CdCl2) resulted in a synergistic effect consisting of an increase in the frequency of recombination. The greatest effects were found on the induction of diploid spores: MMS, hycanthone, and distamycin demonstrated strong, benlate little synergistic action. CdCl2 demonstrated antagonism to caffeine by counter-inhibiting its effect on the induction of diploids. Concerning disomic induction: caffeine reduced (or left unchanged) the effect on non-disjunction when MMS and hycanthone were used. Simple additive effects were caused in conjunction with distamycin, benlate, and (in small doses) CdCl2. 2 mg of caffeine/ml in treatments with CdCl2 resulted in a very high frequency of disomic clones.

Disomic and diploid meiotic products induced in Saccharomyces cerevisiae by the salts of 27 elements

The effects of salts of 27 elements on recombination and on the production of disomic and/or diploid spores during meiosis of Saccharomyces cerevisiae has been investigated. Be(NO3)2, MgSO4, FeSO4, CuSO4, AgNO3, Na2HAsO4 were inactive on the events studied during meiotic cell division. AuCl4, CdCl2, C4H6O4Pb, SnCl2, K2Cr2O7, RbCl induced both disomic and diploid spores. LiCl acted similarly and also affected recombination. Activity in the induction of disomic spores was shown by MnSO4, HgCl2 and SrCl2. CsCl, CaCl2, Na2MoO4, NiCl2, K2PtCl4 increased the frequency of diploid spores, while NaWO4, VOSO4, KCl, BaCl2 already increased recombination frequency. NaBiO3 showed an effect on meiotic recombination only. A decrease in the occurrence of both diploid and disomic spores was suggested by the data obtained with CoCl2.

Effects of some DNA-ligands and of some mutagenic compounds on the induction of meiotic disomic or diploid yeast products

Data were collected following the administration of various compounds to meiotic yeast cultures to investigate their effects on disomic or diploid induction. Epi chlorohydrin, actinomycin D, and 9-aminoacridine were unable to induce either diploidy or disomy. Ethyl methanesulphonate was active in inducing diploids, while hycanthone induced disomics. beta-Propiolactone, N-methyl-N'-nitro-N-nitro-soguanidine, and beta-naphtylamine were able to increase both disomy and diploidy.

Drug synergism or antagonism in the induction of diploid meiotic products in Saccharomyces cerevisiae

The induction of yeast diploid meiotic products by treatment with bleomycin and mitomycin C is reduced when sporulating cells are treated in combination with propranolol, and increased when they are treated in combination with caffeine. We show that bleomycin and mitomycin C act by blocking the second meiotic division. The frequency of this event appears to be directly related to the intracellular cAMP concentration which is known to be influenced in opposite ways by caffeine and propranolol.

Disomic and diploid meiotic products in Saccharomyces cerevisiae. Effect of vincristine, vinblastine, adriamycin, bleomycin, mitomycin C and cyclophosphamide

The effect of some antineoplastic drugs on the induction of disomic and diploid meiotic products in Saccharomyces cerevisiae was evaluated. Vincristine and vinblastine turned out not to be effective on any of the four genetic phenomena studied (sporulation, recombination, disomic induction and diploid induction). Adriamycin showed only slight activity in inducing diploids, particularly during the first meiotic division. Cyclophosphamide was active on both phenomena leading to the formation of disomic and diploid spores. Mitomycin C and bleomycin were effective on the induction of diploids. In all of these inductions, the origin of diploids was due to failure of the second meiotic division. No significant effects were found on recombination frequency. As a general conclusion, one may assume that formation of aneuploid and diploid gametes are two distinct phenomena, not necessarily correlated from the point of view of the mechanism and of the specificity of induction.

Propranolol, atenolol, and trifluoperazine reduce the spontaneous occurrence of meiotic diploid products in Saccharomyces cerevisiae

The effect of atenolol, propranolol, trifluoperazine, and caffeine on the occurrence of meiotic diploid and disomic products in Saccharomyces cerevisiae was investigated. We demonstrated that atenolol, propranolol, and trifluoperazine reduce the occurrence of meiotic diploid products and that propranolol also slightly decreases the spontaneous frequency of disomics. On the other hand, caffeine appears to be a powerful inducer of diploid meiotic products, but also shows a lesser effect on disomic induction. Since spontaneous or caffeine-induced diploids arise from a failure of the second meiotic division, it appears that the target of these drugs is at the beginning of the second meiotic division. The only common effect of trifluoperazine and propranolol, mainly investigated in mammals, was an inhibition of calmodulin activity via direct interaction. We tend, therefore, to believe that calmodulin activity must be a crucial point for the second meiotic division to begin. The increased induction of diploids, due to caffeine, may be interpreted as a consequence of an increased cyclic AMP level.