Surgical pitfalls of an ultrasonic bone curette (SONOPET) in spinal surgery

OBJECTIVE

We report our experience with the SONOPET ultrasonic bone curette.

METHODS

Between September 2001 and July 2005, 546 patients underwent microscopic spinal surgeries using a high-speed drill and the SONOPET instrument.

RESULTS

We encountered operative complications thought to be attributable to the use of the SONOPET in six patients (1.1%). There were five instances of dural puncture and one spinal cord injury. All dural tears occurred when the dura mater was aspirated into the tip of the SONOPET. None of the affected patients developed postoperative clinical complications because cerebrospinal fluid leakage was avoided by appropriate closure. We think that the transient spinal cord injury occurred because the vibration emanating from the SONOPET was transmitted directly to the spinal cord. Some patients experienced damage to the epidural venous plexus for reasons similar to those described above.

CONCLUSION

SONOPET facilitates the removal of bone in a narrow field, such as that encountered during keyhole surgery. It aids in the removal of the lateral edge of bone and is especially useful for expanding the foramen intervertebrale or opening the lateral recess. However, its use is not without risk. To prevent dural tears and venous plexus injury, we recommend that cotton be placed between the SONOPET and important structures. To avoid spinal cord injury, we suggest that the SONOPET be inserted horizontal with the dura mater to avoid the direct transmission of vibrations emanating from the instrument to the spinal cord. SONOPET is suitable for decompression on the lateral side, but not for decompression above the spinal cord.

Anterior decompression via a wide transvertebral approach and a ceramic insert in a patient with cervical degenerative disease

BACKGROUND

The transvertebral approach is useful for decompression in patients with cervical radiculopathy; because the intervertebral disk is preserved, moveability is retained. We performed wide deletion of the vertebral body to increase the patient population eligible for treatment with this approach and include patients with compression of the cervical spinal cord.

METHODS

In patients undergoing anterior decompression, we performed vertebrotomy (13 x 8 mm) at the midline of the cervical vertebral body at the upper level using a surgical saw. The resulting hole facilitates decompression of the cervical cord and nerve root; a ceramic insert is introduced in the area of deletion. To prevent graft extrusion, the bilateral wings of the bone graft are fastened with bioabsorbable screws.

RESULTS

We used this approach in 163 patients with several cervical diseases. Collapse of the vertebral body and fusion of the operated intervertebral disk were encountered in only 1 patient (0.61%). There was no significant difference between pre- and postoperative alignment. Reoperation was required in 7 patients whose symptoms did not improve, in 1 with disk hernia, in 5 with severe spondylosis, and in 1 with combined-type OPLL.

CONCLUSIONS

Although this approach is appropriate in patients undergoing cervical anterior decompression, the narrowness of the visual field may result in insufficient decompression, and its indication is restricted to patients with cervical disk hernia, mild cervical spondylosis, and segmental OPLL. In patients with segmental instability, continuous or combined OPLL, severe cervical spondylosis, and kyphosis, this approach should not be used.

Molecular Loops in the Galactic Center: Evidence for Magnetic Flotation

The central few hundred parsecs of the Milky Way host a massive black hole and exhibit very violent gas motion and high temperatures in molecular gas. The origin of these properties has been a mystery for the past four decades. Wide-field imaging of the (12)CO (rotational quantum number J = 1 to 0) 2.6-millimeter spectrum has revealed huge loops of dense molecular gas with strong velocity dispersions in the galactic center. We present a magnetic flotation model to explain that the formation of the loops is due to magnetic buoyancy caused by the Parker instability. The model has the potential to offer a coherent explanation for the origin of the violent motion and extensive heating of the molecular gas in the galactic center.

Utility of Preoperative Magnetic Resonance Imaging Myelography for Identifying Dural Defects in Patients with Spinal Extradural Arachnoid Cysts: Case Report

OBJECTIVE:

Preoperative magnetic resonance imaging (MRI) myelography scans demonstrated a dural defect in a 50-year-old man with an epidural arachnoid cyst who had a 29-year history of untreated weakness and numbness both lower limbs.

METHODS:

MRI scans showed a dorsal intraspinal extradural cystic lesion at the level from Th11 to L1. Although preoperative cine-MRI scans failed to display the dural defect, an MRI myelography scan showed cerebrospinal fluid in the subarachnoid space containing a cyst.

RESULTS:

The site of shunting between the subarachnoid space and the cyst was visualized as a pulsating flow void to the right of Th12. We removed the cyst wall and closed the dural defect via laminectomy.

CONCLUSION:

Because the preoperative MRI myelography scan correctly identified the existence and location of the dural defect, we conclude that MRI myelography is helpful for detecting dural defects in patients with epidural arachnoid cysts.

Identification of basophils by a mAb directed against pro-major basic protein 1

BACKGROUND

Basophils possess characteristics of both mast cells and eosinophils, and all 3 cell types often are found together, particularly during allergic reactions. A mAb (J175-7D4) generated against the recombinant pro-form of human eosinophil granule major basic protein 1 (rproMBP1) appeared to stain only basophils in tissue specimens.

OBJECTIVE

We investigated J175-7D4 to characterize its specificity for basophils.

METHODS

Fluid-phase immunoprecipitation, Western blotting, and immunocytochemistry and immunohistochemistry were used to establish the specificity of J175-7D4.

RESULTS

First, J175-7D4 binds to various glycosylated and proteolytically processed forms of rproMBP1, but not to major basic protein. Second, cells transfected with the rproMBP1 gene and human placental tissue (known to express the pro-form of major basic protein 1 [proMBP1]) stain specifically with J175-7D4. In contrast, although mature eosinophils contain substantial major basic protein, they lack proMBP1 and do not stain. Neutrophils, lymphocytes, monocytes, and skin mast cells also are not stained. However, blood basophils are stained by J175-7D4, anti-IgE, Wright-Giemsa (metachromatically), and a previously characterized basophil-specific mAb, 2D7. Finally, formaldehyde-fixed, paraffin-embedded basophils are identically detected by J175-7D4 and 2D7, and J175-7D4 also recognizes putative basophils in formaldehyde-fixed, paraffin-embedded tissue specimens from inflammatory dermatoses, such as atopic dermatitis and delayed pressure urticaria.

CONCLUSION

The J175-7D4 mAb recognizes proMBP1 as a novel marker for human basophils. J175-7D4 should prove useful for characterizing basophil involvement in human health and disease.

Ictal monoparesis associated with lesions in the primary somatosensory area

Reported are three patients with ictal monoparesis of an arm. In the hemisphere contralateral to the monoparesis, ictal and interictal epileptiform discharges were observed in the centroparietal area, and a well-circumscribed lesion was commonly present in the primary arm somatosensory area (SI). In the presence of an SI lesion, the epileptic activity at the sensorimotor area could lead to selective or predominant activation of the inhibitory motor system.

Angiotensin converting enzyme inhibitor prevents left ventricular remodelling after myocardial infarction in angiotensin II type 1 receptor knockout mice

BACKGROUND

It is well known that angiotensin converting enzyme (ACE) inhibitors and angiotensin II type 1 (AT1) receptor blockers (ARBs) prevent left ventricular (LV) remodelling after myocardial infarction (MI). However, it is still not clear whether inhibition of the AT1 receptor is enough to prevent LV remodelling after MI.

OBJECTIVE

To elucidate the effects of ACE inhibitors that are not mediated by the AT1 receptor on LV remodelling, MI was experimentally induced in wild-type (WT-MI) mice and AT1 receptor knockout (KO-MI) mice.

METHODS

Mice were divided into six groups: WT-control, KO-control, WT-MI, KO-MI, WT-MI treated with an ACE inhibitor, and KO-MI treated with an ACE inhibitor. Four weeks after MI, cardiac function was assessed by Doppler echocardiography and non-infarcted myocardial mRNA expression by northern blot analysis.

RESULTS

Cardiac function decreased significantly in the MI groups compared with the sham operated groups. Additionally, in the MI groups end diastolic dimension, E wave velocity, the ratio of peak velocity of E wave to A wave, deceleration rate of E wave, and mRNA expression of atrial natriuretic peptide, brain natriuretic peptide, and collagens I and III increased significantly compared with the sham groups. LV remodelling after MI was prevented in KO-MI mice compared with WT-MI mice. ACE inhibitor administration significantly attenuated progressive LV remodelling in both WT and KO-MI groups.

CONCLUSION

ACE inhibitors can prevent the LV remodelling process that accompanies cardiac dysfunction after MI, even in AT1 KO mice. These findings suggest that ACE inhibitors prevent LV remodelling after MI by mechanisms other than inhibition of angiotensin AT1 receptor mediated effects.

Development of prostaglandin D2 receptor antagonist: discovery of highly potent antagonists

The process of discovery for highly potent prostaglandin D(2) (PGD(2)) receptor antagonists is reported. A series of N-(p-alkoxy)benzoyl-2-methylindole-4-acetic acids were synthesized and identified as a new class of selective PGD(2) receptor antagonists. Most of them exhibited strong PGD(2) receptor antagonism in binding studies and the cAMP formation assay. The structure-activity relationships (SAR), including subtype selectivity of the synthesized compounds, are also discussed.

Microbubble destruction with ultrasound augments neovascularisation by bone marrow cell transplantation in rat hind limb ischaemia

OBJECTIVE

To examine the effects of microbubble destruction with ultrasound (MB) combined with bone marrow derived mononuclear cell transplantation (BMT) into ischaemic tissues in rat hind limb ischaemia.

METHODS AND RESULTS

Unilateral hind limb ischaemia was surgically induced in Lewis rats. At postoperative day 7, rats were randomly divided into three groups: a vehicle treated group, an ultrasound treated group, and an MB treated group. MB treatment increased vascular endothelial growth factor mRNA as assessed by real time polymerase chain reaction (3.0-fold, p < 0.05). At four weeks, the MB group had increases in laser Doppler blood flow index (LDBFI; 1.2-fold, p < 0.05), angiographically detectable collateral vessels (angiographic score: 1.4-fold, p < 0.01), and capillary to muscle fibre ratio (1.4-fold, p < 0.01) in ischaemic limbs compared with the vehicle treated group. No differences were seen between the vehicle and ultrasound treated groups. Secondly, rats were allocated to vehicle treatment, BMT (5 x 10(6) cells/rat), or a combination of MB and BMT (MB+BMT) at seven days after hind limb ischaemia. BMT treatment significantly increased LDBFI, angiographic score, and capillary to muscle fibre ratio compared with vehicle treatment. Interestingly, MB+BMT treatment produced significantly greater LDBFI (1.2-fold, p < 0.01), angiographic score (1.5-fold, p < 0.01), and capillary to muscle fibre ratio (1.5-fold, p < 0.05) than BMT treatment alone.

CONCLUSIONS

MB may be a useful technique to enhance BMT induced neovascularisation.

Effects of eplerenone on transcriptional factors and mRNA expression related to cardiac remodelling after myocardial infarction

OBJECTIVE

To examine the effects of eplerenone, a selective aldosterone blocker, on cardiac function after myocardial infarction (MI) and myocardial remodelling related transcriptional factors and mRNA expression in non-infarcted myocardium.

METHODS

MI was induced by ligation of the coronary artery in Wistar rats. Rats were randomly assigned to a vehicle treated group or an eplerenone treated group (100 mg/kg/day).

RESULTS

At four weeks after MI, left ventricular (LV) end diastolic pressure, LV weight, and LV end diastolic dimension were increased in MI rats. Eplerenone significantly reduced the increase in LV end diastolic pressure, LV weight, and LV end diastolic dimension. In the MI rats the decreased ejection fraction indicated systolic dysfunction and the increased E wave to A wave ratio and E deceleration rate indicated diastolic dysfunction. Eplerenone significantly attenuated this systolic and diastolic dysfunction. Myocardial interstitial fibrosis, transcriptional activities of activator protein 1 and nuclear factor kappaB, and mRNA expression of monocyte chemoattractant protein 1, plasminogen activator inhibitor 1, atrial natriuretic peptide, brain natriuretic peptide, and collagen types I and III were significantly increased at four weeks after MI. Eplerenone significantly attenuated interstitial fibrosis and suppressed transcriptional activity and mRNA expression of these genes.

CONCLUSIONS

When administered after MI, eplerenone prevents cardiac remodelling accompanied by systolic and diastolic dysfunction and inhibits abnormal myocardial transcriptional activities and gene expression.

Discovery of orally active prostaglandin D2 receptor antagonists

A series of N-(p-alkoxy)benzoyl-2-methylindole-4-acetic acids were synthesized and evaluated for prostaglandin D(2) (DP) receptor affinity and antagonist activity. Some of them exhibited strong receptor binding and were potent in the cAMP formation assays. These antagonists also suppressed allergic inflammatory responses such as the PGD(2)-induced increase of microvascular permeability. Structure-activity relationship (SAR) data are presented.

Discovery of a new class of potent, selective, and orally active prostaglandin D2 receptor antagonists

The process of discovering a series of N-(p-alkoxy)benzoyl-2-methylindole-4-acetic acid analogs is presented since these compounds represent a new class of potent, selective, and orally active prostaglandin D2 (PGD2) receptor antagonists. Most of these compounds exhibit strong PGD2 receptor binding and PGD2 receptor antagonism in cAMP formation assays. When given orally, these new antagonists dramatically suppress allergic inflammatory responses, such as the PGD2-induced or OVA-induced increase of vascular permeability. Structure-activity relationship (SAR) data are also discussed.

Subregions of human MT complex revealed by comparative MEG and direct electrocorticographic recordings

OBJECTIVE

To locate the visual motion complex (MT+) and study its response properties in an epilepsy surgery patient.

METHODS

A 17-year-old epilepsy patient underwent invasive monitoring with subdural electrodes in the right temporo-parieto-occipital area. MT+ was investigated by cortical electric stimulation and by epicortical visual evoked potentials time-locked to motion onset of sinusoidal gratings (motion VEP). Motion-related visual evoked magnetic field (motion VEF) was also recorded before the electrode implantation to complement the invasive recording.

RESULTS

Motion VEPs revealed two subregions within MT+, generating early and late potentials respectively. The early activity with a peak around 130 ms was localized at a single electrode situated immediately caudal to the initial portion of the ascending limb of the superior temporal sulcus (AL-STS). The late activity, peaking at 242-274 ms, was located ventro-rostrally over three electrodes. Among the four electrodes with motion VEPs, cortical stimulation at the most caudal pair elicited motion-in-depth perception involving the whole visual field. In addition to two subregions revealed on the gyral crown, magnetoencephalography (MEG) demonstrated another subregion with a late motion VEF in AL-STS immediately rostral to the electrode with the early motion VEP.

CONCLUSIONS

In combination with MEG recording, the present invasive exploration demonstrated human MT+ in a focal area of the temporo-parieto-occipital junction and delineated possible three subregions as indicated by the different latencies and distributions of the motion VEP/VEFs.

SIGNIFICANCE

Comparative MEG and direct electrocorticographic recordings delineated possible subregions within the human MT complex.

Intracarotid propofol test for speech and memory dominance in man

OBJECTIVE

To evaluate the usefulness of propofol as an alternative drug to amobarbital for the Wada test.

METHODS

The authors analyzed 67 right-handed patients out of 123 patients who were candidates for neurosurgical therapy and thus underwent the Wada test as a preoperative evaluation. Twelve were tested with propofol and 55 were tested with amobarbital. Test conditions of the Wada test, recovery time of muscle power to manual muscle testing (MMT) Grade 3 (T3/5) and Grade 5 (T5/5), onset time of the first verbal response (Tverb) after injection and that of the first nonverbal response (Tnon-verb), were compared between the two groups. Power spectrum analysis of EEG background activity during the Wada test was performed and the time and spatial distribution of polymorphic slow activities were also compared in three cases.

RESULTS

With propofol injection, lateralities of language and memory function were identified in 12 and 9 of 12 patients in comparison to amobarbital (52 and 41 of 55 patients detection in language and memory function). No complications with direct intracarotid injection of propofol were observed. T3/5 and T5/5 with propofol injection were shorter while Tverb and Tnon-verb were longer compared to amobarbital. Absolute power of polymorphic slow EEG waves gradually increased and then rapidly decreased with propofol, which was in contrast to amobarbital injection.

CONCLUSIONS

With direct intracarotid propofol injection, the Wada test was satisfactorily performed in all 12 patients and 2 more patients with left-handedness or with different injection dose for each side without any complications. Clinical usefulness of propofol as an alternative drug to amobarbital for the Wada test was indicated.

Molecular characterization of a 10-kDa buckwheat molecule reactive to allergic patients' IgE

BACKGROUND

Using the sera from buckwheat (BW)-allergic patients, several putative causative molecules were reported. However, few molecules were determined on the molecular structure. We demonstrated in 2000 that the major allergen with 24 kDa (BW24KD) is a legumin-like storage protein.

OBJECTIVE

The aim of this study was to isolate and characterize further a major allergen with 10 kDa by molecular cloning.

METHODS AND RESULTS

Buckwheat allergens were identified by immunoblotting analysis using sera from 14 allergic and two nonallergic individuals. We identified a protein with 10 kDa (BW10KD) that reacted with immunoglobulin E (IgE) more strongly than with IgG and IgA in 57% of the allergic patients but not with IgE in nonallergic individuals. Analyses were performed by N-terminal amino acid sequencing and molecular cloning. Physiological significance was assessed by an immunoblotting experiment showing that the reactivity of an allergic patient's serum IgE to BW10KD was competitively inhibited by natural BW extracts.

CONCLUSION

Molecular cloning experiments indicated that BW10KD as a BW allergen was a member of the 2S-albumin multigene family.

Seizures arising from the inferior parietal lobule can show ictal semiology of the second sensory seizure (SII seizure)

A 52-year-old right handed man presented with medically intractable partial seizures consisting of numbness on the left upper back spreading to the left upper as well as lower limbs. Head computed tomography and magnetic resonance imaging showed a round calcified lesion in the depth of the superior ramus of the right sylvian fissure. Ictal electrocorticographic recording with chronically implanted subdural electrodes showed low voltage fast activities starting exclusively from an electrode located on the right inferior parietal lobule. No apparent ictal activities were observed from the depth electrodes inserted in the parietal operculum. Somatosensory evoked potentials of 75 ms to 145 ms latency were recorded from the ictal onset zone, which was 2 cm caudal to the perisylvian area corresponding to the second somatosensory area. Seizures arising from the inferior parietal lobule including the angular and supuramarginal gyri can produce partial seizures whose ictal semiology and scalp electroencephalography are indistinguishable from the ones originating from the second somatosensory area.

Effect of Ca2+-dependent cell death on the release of herpes simplex virus

The effect of a variety of cell death-inducing reagents on the release of herpes simplex virus type 1 (HSV-1) was examined. Ionomycin was found to increase the release of HSV-1, whereas no significant increase was observed by the treatment with TNF-alpha, anti-Fas antibody, C2-ceramide, sphingosine, H-7, tyrphostin and camptothecin. Ionomycin induced an immediate early peak and a subsequent long-lasting elevation of intracellular Ca(2+) concentration ([Ca(2+)]i). In the absence of extracellular Ca(2+), ionomycin neither elevated [Ca(2+)]i nor increased the release of HSV-1 from the infected cells, indicating that Ca(2+) influx play an important role in the release of HSV-1. Studies with trypan blue and annexin V staining revealed that the ionomycin-induced alteration of [Ca(2+)]i was accompanied by cell death of the infected cells. Disintegration of cell membrane, cytoplasmic vacuole formation and the leakage of virus particles from the cell surface were observed by electron microscopy. These results indicate that Ca(2+)-dependent cell death showing necrotic alteration is responsible for the enhanced release of HSV-1. The data also give some initial insights into the functional importance of cell death during the late stages of HSV-1 infection.