Correlation of low CT attenuation and necrotic features of tumor in contrast-enhanced CT with nivolumab response

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Background: Anti-PD1/PD-L1 antibodies, including nivolumab, produce durable responses in non-small cell lung cancer (NSCLC), but the response rate is about 20% in unselected NSCLC. Identifying predictive markers of response is necessary. Although PD-L1 expression may be a potential biomarker, evaluating whole tumors based on a small sample is difficult. Identifying radiographic features of responders can be very useful. We hypothesized that low attenuation on computed tomography (CT), considered to represent necrosis, correlates with nivolumab response. Methods: We retrospectively evaluated contrast-enhanced CT images before treatment and tumor response in 60 patients receiving nivolumab. The largest tumor lesion was characterized in each patient. CT attenuation (CTA) of whole tumor areas was measured; the presence of radiological findings of necrosis (necrotic features), presenting cavitation or ring- or patchy-enhancement in tumors, were assessed. We evaluated the association between CT imaging characteristics and nivolumab response and that between CT imaging characteristics and PD-L1 expression in tumors. Results: Thirty-nine target lesions in lung, 12 in lymph node, and 9 in other organs were chosen. The mean CTA was 58.5 ± 15.3 HU. Necrotic feature were observed in 24 (40%) of 60 lesions.Twenty of 60 lesions (33%) shrank to > 30% with nivolumab treatment. Mean CTA in responding lesions was 48.6 HU, significantly lower than that in nonresponding lesions (63.4 HU) (p < 0.001). The response rate of lesions with/without necrotic features was 45% and 28%, respectively (p = 0.246).Systemic tumor response, assessed by RECIST v1.1, was confirmed in 20 (33%) patients. Mean CTA of target lesions was lower in responders than patients with stable disease or progressive disease (51.4 vs. 62.0 HU, p = 0.011). The systemic response rate of lesions with/without necrotic features was 50% and 25%, respectively (p = 0.081).Mean CTA of target lesions was lower in tumors with high PD-L1 expression than in tumors with low PD-L1 expression (54.8 vs. 64.4 HU, p = 0.045). Conclusions: Low CTA and necrotic features in CT may correlate with nivolumab response. Tumors with low CTA may have high PD-L1 expression.

Mechanical Thrombectomy Using the Trevo ProVue in 50 Consecutive Patients with Anterior Circulation Stroke: A Single-Center Experience after Approval of the Stent Retriever in Japan

Mechanical thrombectomy using the stent retriever has been proven to be effective for select patients with acute ischemic stroke. We evaluated our early experience using the device after its approval in 2014 in Japan, with a special emphasis on the occlusion site. Fifty consecutive endovascular revascularization procedures for treating anterior acute large vessel occlusion were performed using the Trevo ProVue as the first-line device at our institute between April 2015 and March 2016. Focusing on the involvement of the M1-M2 bifurcation with deployment or retrieval of the stent retriever, we regarded the middle cerebral artery M1 mid-portion as the boundary and divided the cases into proximal (n = 26) and distal (n = 24) groups. We assessed the overall clinical outcome and compared the outcome between the two groups. Among 50 patients (median age, 80 years; National Institutes of Health Stroke Scale score (NIHSS) score, 20), successful (modified Thrombolysis in Cerebral Infarction score (TICI) 2b or 3) or complete revascularization (TICI 3) was achieved in 41 patients (82%; 88% in the proximal group vs 75% in the distal group, P = 0.28) and in 27 patients (54%; 73% vs 33%, P = 0.01), respectively. Symptomatic intracranial hemorrhage occurred in three patients (6%; 4% vs 8%, P = 0.60). A good outcome (mRS score 0 to 2) was obtained in 25 patients at 90 days (50%; 54% vs 46%, P = 0.78). Mechanical thrombectomy using the Trevo ProVue was safe and effective in patients with acute cerebral artery occlusion, especially for proximal occlusions. The efficacy of the procedure for distal occlusions was somewhat inferior to those for proximal occlusions, which might be resolved by next generation devices.

[Association of Deep Venous Thrombosis with D-dimer Values in Patients with Hemorrhagic Stroke]

Pulmonary embolism(PE)in the early phase of stroke worsens the prognosis. It is necessary to detect deep venous thrombosis(DVT)to avoid PE. We conducted the D-dimer screening in order to detect DVT at an earlier stage. We retrospectively analyzed the clinical data of patients with hemorrhagic stroke who were admitted to the local stroke center, and investigated the complication rates of DVT, PE, D-dimer values, and risk factors of DVT. From October 2012 to August 2014, 261 patients were included. DVT was detected in 46 patients(17.6%)and anticoagulant therapy was started in 5 patients with central DVT. PE did not occur during this observation period. The D-dimer cutoff value for estimating the presence of the DVT was 8.9μg/mL, and the risk factors for DVT were older age, severe neurological disability, prolonged hospital stays, and subarachnoid hemorrhage. D-dimer screening is very useful to make earlier diagnosis and treatment of DVT.

Anaplastic and meningothelial meningiomas in a single tumor: A "dedifferentiated meningioma"?

The patient was a 74-year-old man, who developed progressive cognitive impairment and gait instability. Neuroradiological examination demonstrated a large and predominantly extra-axial tumor spreading over the bilateral frontal base, indicative of olfactory groove meningioma. The greater part of the resected tumor consisted of a dense, patternless proliferation of large, round or polygonal cells, and compactly fascicular growth of spindle cells. Tumor cells showed markedly anaplastic cytological features. In small areas of the tumor, a typical meningothelial meningioma showing no cellular atypism was found. Both tumor components were closely juxtaposed and no pathological features of an intermediate grade (atypical meningioma) were noted. Shortly after the operation, the patient developed a local recurrence of the tumor and multiple metastases to the cerebrum, bone and skin. Anaplastic meningioma is a rare, highly malignant neoplasm which arises de novo or as a result of the progressive transformation of a low-grade meningioma. The coexistence of anaplastic and low-grade components in a single meningeal tumor has been rarely reported. This dimorphic appearance is reminiscent of "dedifferentiation", a phenomenon infrequently seen in various mesenchymal and salivary gland neoplasms. We think that the term "dedifferentiated meningioma" can be appropriately applied to tumors such as that reported herein.

Minimum Transpetrosal Retrolabyrinthine Approach for Revascularization of Posterior Cerebral Artery: Operative Nuance

BACKGROUND

Revascularization of the posterior cerebral artery (PCA) can be essential for treating complex cerebral aneurysms in the posterior circulation, and it is considered technically challenging. To help decrease the difficulty of this technique, we developed the minimum transpetrosal approach (MTPA).

OBJECTIVE

The technical nuances of the MTPA were innovated by cadaver head dissections and an actual clinical case.

METHODS

Four sides of the formalin-fixed cadaver heads were used to investigate if the posterior cerebral artery could be exposed with this minimum retraction of the temporal lobe in the subtemporal approach and the MTPA. By using the MTPA, 1 patient harboring a ruptured PCA aneurysm underwent superficial temporal artery-PCA anastomosis followed by isolation of the aneurysm.

RESULTS

In the cadaver head dissections, we noticed that the PCAs were difficult to expose with gentle retraction of the temporal lobe in the subtemporal approach. By performing an additional retrolabyrinthine mastoidectomy, performed as the MTPA, all 4 PCAs were easily exposed in the 4 wide surgical fields. The maximum widths of the surgical fields above and below the PCA could be successfully measured in 2 cases, which were 13.3 mm and 11.2 mm, respectively (mean, 12.3 mm). Additionally, in the actual live surgery using MTPA, the PCAs were relative easy to expose with a surgical field wide enough to perform PCA bypass, which was performed without complication.

CONCLUSION

The MTPA may be the most favorable approach for PCA bypass that can be performed easily with minimal temporal lobe retraction.

Histidine-rich protein as a possible origin of free amino acids of stratum corneum

The origin of free amino acids and/or their metabolites of the stratum corneum was investigated by pulse-chase experiments using hairless mice. Two, 24, 48, and 72 hrs after the animals were pulse-chased with 3H-histidine or 3H-arginine, radioactivity was determined in the following three fractions of the epidermis: the 0.1 N HClO4 soluble, ethanol soluble fraction (Fr. I); the 0.1N NClO4 soluble, ethanol insoluble fraction (Fr. II); and the 0.1 N HClO4 insoluble, 8M urea soluble fraction (Fr. III). Radioactivity of the epidermal proteins was also determined in SDS-PAGE gels by the gel slicing method. At first, 3H-histidine and/or 3H-arginine were predominantly incorporated into Fr. III, especially into a certain epidermal protein which showed little mobility on SDS-PAGE. Subsequently, 3H, once incorporated into Fr. III, appeared to shift from Fr. III to Fr. II and, simultaneously, from the top band(s) to a band of 32,000 daltons. As a result of amino acid analysis, a protein of Fr. II was considered a histidine-rich protein corresponding to HRP-II of the new born rats of Ball et al. After 48 hrs, as the radioactivities of Fr. III and Fr. II decreased remarkably, Fr. I gradually increased in radioactivity. The major radioactive substances in Fr. I at 72 hrs were identified as 3H-histidine and 3H-urocanic acid when 3H-histidine was used as a tracer, and as 3H-arginine, 3H-ornithine, and 3H-citrulline in the case of 3H-arginine. The amino acid composition of the histidine-rich protein was very similar to that of the free amino acids of the stratum corneum in the hairless mouse, in which some amino acid metabolites were considered as their precursor amino acids. These results strongly suggest that the free amino acids and/or their metabolites of the stratum corneum might be the final products of a degradation of the histidine-rich protein.

The novel VEGF receptor antagonist, VGA1155, reduces edema, decreases infarct and improves neurological function after stroke in rats

Vascular endothelial growth factor (VEGF) is a major mediator of angiogenesis and also a strong vascular permeability factor. Blockade of VEGF may have a potential to treat cerebral edema after brain injury. We evaluated the effect of VGA1155 (5- [N-Methyl-N-(4-octadecyloxyphenyl)acetyl]amino-2- methylthiobenzoic acid), a novel binding antagonist of VEGF, on cerebral edema after transient focal cerebral ischemia. Focal cerebral ischemia was induced with the suture occlusion method for 2 h. In the treatment group, a single dose of VGA1155 (1 ~ 50 mg/kg i.p.) was administrated 30 min before the induction of focal ischemia, and the vehicle group received phosphate buffer only. The brain water content, Evans blue extravasation, infarct volumes and neurological score were determined. Physiological parameters were not influenced by the administration of VGA1155. The brain water content at 24 h after cerebral ischemia was significantly reduced by intraperitoneal administration of VGA1155 and the dose of 10 mg/kg showed the maximum effect on brain water content (81.8 ± 0.5% in non treated group vs. 80.2 ± 0.6% in treated group). With this dose, VGA1155 also reduced vascular permeability from 2.2 ± 0.8 µg/g to 1.2 ± 0.5 µg/g studied at 6 h after the ischemia by intravenous injection of Evans blue. VGA1155 administration significantly reduced infarct volume and improved neurological scores at 1 week after ischemic injury. The data suggested that VGA1155 has antiedematous effect in acute phase after transient focal cerebral ischemia and improves neurological and histological outcomes 1 week after ischemic injury.

Anti-VEGF receptor antagonist (VGA1155) reduces infarction in rat permanent focal brain ischemia

BACKGROUND AND PURPOSE

Vascular endothelial growth factor (VEGF) is a major mediator of angiogenesis and a strong vascular permeability factor. VEGF is known to open the blood-brain barrier (BBB) and induce cerebral edema. Experimental studies of VEGF antagonism have shown it reduces cerebral edema after ischemia, indicating its potential for prevention of secondary brain damage. We examined the therapeutic effect of VGA1155 (5- [N-Methyl-N- (4-octadecyloxyphenyl) acetyl] amino-2-methyl-thiobenzoic acid), a novel small molecule antagonist of VEGF, on rat permanent focal cerebral ischemia.

METHODS

Permanent middle cerebral artery occlusion (MCAO) was induced with the suture occlusion method. A single dose of VGA1155 (10mg/kg, i.p.) was administered 30 minutes before the induction of MCAO after which brain water content, Evans blue extravasation, neurological score, infarct volumes and VEGF expression determined by means of ELISA were compared with corresponding values for vehicle injected control rats.

RESULTS

Brain water content and Evans Blue extravasation 24 hours after ischemia were not significantly reduced, but, compared with control group, VGA1155 significantly reduced infarct volume (32.0% for VGA1155 vs. 46.7% for control; % volume of hemisphere volume) and improved neurological function 7 days after ischemia, when tissue content of the VEGF group markedly increased to nine times that of the vehicle-treated animals.

CONCLUSION

VGA1155 was found to protect against secondary ischemic brain damage after permanent focal cerebral ischemia, although it did not reduce vasogenic edema at 24 hours. Changes in endogenous VEGF may be related to the therapeutic effect of VGA1155.

Long-term survival with non-functioning pituitary carcinoma - case report -

A 35-year-old woman presented with a non-functioning pituitary adenoma manifesting as amenorrhea and impaired visual acuity in 1984. The tumor was grossly totally resected through a right frontotemporal craniotomy. The patient underwent surgery for three recurrences in the next 5 years. She was treated with gamma knife surgery for the residual tumor in 1994. Follow-up magnetic resonance (MR) imaging revealed a tumor in the right frontal base in 1999, and the left middle fossa in 2002. Total removal of these tumors was performed. Follow-up MR imaging showed regrowth of the primary pituitary tumor in 2003, which was partially excised. Histological examination of the specimens from the last three surgeries revealed typical pituitary adenoma without malignant transformation. Pituitary carcinomas have a poor prognosis. However, the present patient survived for 22 years from onset and 6 years from the first dural metastasis. Distant lesions should be removed for histological evaluation to assist the subsequent management.

Telecontrolled micromanipulator system (NeuRobot) for minimally invasive neurosurgery

BACKGROUND

To perform less invasive neurosurgery, a telecontrolled micromanipulator system has been developed and applied to clinical situations. Basic experiments for telesurgery have also been conducted.

METHOD

A cadaver head was used to carry out surgical simulation of the opening of the sylvian fissure and third ventriculostomy. After obtaining permission from the Ethical Committee of Shinshu University School of Medicine, part of the recurrent meningioma in a 45-year-old man was removed. As basic experiment for telesurgery, surgical simulation was also conducted in a rat brain with the operating console transported to a hospital 40 km distant from the University.

FINDINGS

Opening of the sylvian fissure and third ventriculostomy were accurately performed. Tumour removal in a patient with recurrent meningioma was safely achieved. Surgical simulation in the rat brain was accurately and correctly carried out, operated on from a hospital 40 km distant.

CONCLUSIONS

The NeuRobot, telecontrolled micromanipulator system, can be used as a tool for less invasive neurosurgery.

Four cases of thrombotic events associated with neuro-endovascular therapy: heparin resistance and aspirin resistance

SUMMARY

Thrombotic events are caused by insufficient antithrombotic treatment in endovascular surgery. We experienced four cases of thrombotic events and consider the factors from the point of view of heparin resistance and aspirin resistance. The proportion of these features is quite high and appropriate management is important.