Dysbiosis of Gut Microbiome Is Associated With Rupture of Cerebral Aneurysms.

BACKGROUND AND PURPOSE: Environmental factors are important with respect to the rupture of cerebral aneurysms. However, the relationship between the gut microbiome, an environmental factor, and aneurysm rupture is unclear. Therefore, we compared the gut microbiome in patients with unruptured intracranial aneurysms (UIAs) and ruptured aneurysms (RAs) to identify the specific bacteria causing the rupture of cerebral aneurysms. METHODS: A multicenter, prospective case-control study was conducted over one year from 2019 to 2020. The fecal samples of patients with stable UIAs and RAs immediately after onset were collected. Their gut microbiomes were analyzed using 16S rRNA sequencing. Subsequently, a phylogenetic tree was constructed, and polymerase chain reaction was performed to identify the specific species. RESULTS: A total of 28 RAs and 33 UIAs were included in this study. There was no difference in patient characteristics between RAs and UIAs: age, sex, hypertension, dyslipidemia, diabetes status, body mass index, and smoking. No difference was observed in alpha diversity; however, beta diversity was significantly different in the unweighted UniFrac distances. At the phylum level, the relative abundance of Campylobacter in the RA group was larger than that in the UIA group. Furthermore, the gut microbiome in the RA and UIA groups exhibited significantly different taxonomies. However, Campylobacter was focused on because it is widely known as pathogenic among these bacteria. Then, a phylogenetic tree of operational taxonomic units related to Campylobacter was constructed and 4 species were identified. Polymerase chain reaction for these species identified that the abundance of the genus Campylobacter and Campylobacter ureolyticus was significantly higher in the RA group. CONCLUSIONS: The gut microbiome profile of patients with stable UIAs and RAs were significantly different. The genus Campylobacter and Campylobacter ureolyticus may be associated with the rupture of cerebral aneurysms.

[Carotid Artery Stenting in a Tortuous Artery Results:A Case Report].

BACKGROUND: After carotid artery stenting(CAS)in a tortuous artery, the geometrics and elongation of the carotid artery sometimes change. It is not clear whether these changes induce post stent re-stenosis. We report a case of re-stenosis that occurred two years after CAS in a tortuous artery that required carotid endarterectomy with removal of the stent. CASE PRESENTATION: CAS was performed on a 78-year-old male who presented with symptoms of severe stenosis of a tortuous internal carotid artery. Eighteen months after stenting, the echogram revealed moderate stenosis at the distal end of the stent. Six months later, this developed into severe stenosis. Carotid angiography showed that the end of the stent was touching the wall of the internal carotid artery, and blood was passing through the stent wall. A re-CAS was difficult to perform;hence carotid endarterectomy with removal of the stent was performed successfully. He was discharged without any new neurological deficits. CONCLUSION: CAS on a tortuous carotid artery sometimes results in changes to the geometry and elongation of the artery. Potentially, this can lead to changes in the positional relationship between the stent and the artery, alteration of the wall shear stress and re-stenosis. Careful follow-up is needed after CAS on a tortuous artery.

[Ruptured Dissecting Distal Superior Cerebellar Artery Aneurysm Successfully Treated with Coil Embolization: A Case Report].

BACKGROUND: Ruptured dissecting superior cerebellar artery aneurysms are rare, and only 12 cases have been reported. We report a case of dissecting aneurysm of the distal superior cerebellar artery presenting with subarachnoid hemorrhage. CASE PRESENTATION: An 80-year-old man presented with a three-day history of headache and diplopia. CT revealed slight subarachnoid hemorrhage and CT angiography demonstrated a dissecting aneurysm located in the distal portion of the left superior cerebellar artery. Initially, we chose conservative therapy. Ten days later, the patient became drowsy. Repeat CT showed that the amount of the subarachnoid hematoma increased and the aneurysm enlarged. Emergent endovascular coil embolization with parent artery occlusion was performed successfully. Postoperative MRI revealed no infarction in the cerebellum or brain stem. Delayed ischemic deficits were not observed after treatment. CONCLUSION: Endovascular parent artery occlusion of the distal superior cerebellar artery is an effective method with low morbidity for treatment of ruptured dissecting distal superior cerebellar artery aneurysms.

Paradoxical Worsening of Cerebral Venous Sinus Thrombosis Due to Heparin-Induced Thrombocytopenia: A Case Report and Literature Review.

Development of cerebral venous sinus thrombosis (CVST) is a rare manifestation of heparin-induced thrombocytopenia (HIT). Herein, we present a case in which heparin administration for primary CVST caused paradoxical worsening of CVST secondary to HIT. A 53-year-old woman diagnosed with CVST was provided with intravenous unfractionated heparin therapy. After 12 days, the patient presented tonic convulsive seizures (TCS). Subsequent magnetic resonance image (MRI) scans revealed an exacerbation of cerebral edema with a subcortical hemorrhage on the left parietal lobe. Laboratory test results revealed a significant decline in platelet count. Heparin was immediately discontinued and replaced with argatroban. The definitive diagnosis of HIT was made through the presence of HIT antibodies. The present case, in which HIT caused the secondary CVST exacerbation, is distinctly rare. Our case provides an instructive example by highlighting the potential of TCS as the first sign of HIT development during CVST treatment.

Technique for Recanalization of Sheath Introducer Occlusion due to Captured Thrombus during Mechanical Thrombectomy for Acute Ischemic Stroke: A Technical Note.

Objective: Mechanical thrombectomy (MT) is the gold standard treatment for acute ischemic stroke. During these interventions, a thrombus frequently obstructs a guiding catheter. The obstructed guiding catheter should be withdrawn before distal embolism occurs; however, albeit infrequently, the thrombus occludes even a sheath introducer (SI). While conventionally new SI placement is required for continuation of treatment, we propose a viable alternative for recanalization of the occluded SI, termed vacuum-assisted delivery of thrombus (VADT), with a clinical report of our cases. The usefulness of this technique was also evaluated in simulation experiments. Case Presentations: The VADT procedure is as follows: 1) insert a peel-away sheath, originally attached to a balloon-guiding catheter (BGC), into the SI to continuously open the hemostatic valve; 2) advance the BGC into the peel-away sheath while applying mechanical aspiration; and 3) remove the peel-away sheath/BGC assembly slowly. In a simulation environment using an artificial thrombus, we repeated the VADT procedure five times and reproducibly achieved SI reopening within only 10-20 seconds. From March 2013 to September 2022, 204 patients were treated with MT at our stroke center and SI occlusion occurred in three patients (1.5%). These events occurred exclusively in patients with extracranial internal carotid artery occlusion. All three patients with SI occlusion underwent successfully thrombus extraction in the SI using the VADT on the first try. Conclusion: The results of clinical experience and simulation experiments strongly support VADT as a reliable option for recanalization of an occluded SI.

An anomalous hyperplastic anterior choroidal artery associated with an unruptured internal carotid-posterior communicating artery aneurysm.

The anterior choroidal artery (AChA) injuries can result in severe neurologic deficits, so requiring careful observation to avoid inadvertent damage during neuroendovascular procedures. In this case report, we present the unusual case of an anomalous hyperplastic AChA associated with a fetal-type posterior communicating artery (PCoA), and an unruptured internal carotid artery (ICA) -PCoA aneurysm. A 54-year-old woman presented with persistent headache. Brain magnetic resonance imaging (MRI) showed an unruptured cerebral aneurysm in the right ICA, and cerebral angiography revealed a proximal fetal-type PComA and a distal anomalous hyperplastic AChA. Coil embolization was performed with no neurologic deficits and the target lesion was embolized with a total of 6 coils. An anomalous hyperplastic AchA has a lengthy course with numerous choroidal and perforating branches, and therefore, an abundant perfusion region. Thorough knowledge of the development and anatomy of anomalous arteries is important for safely performing endovascular procedures without causing any ischemic complications.

Efficacy of transcutaneous cardiac pacing for transient asystole caused by trigeminocardiac reflex: illustrative case.

BACKGROUND: Trigeminocardiac reflex (TCR) is a brainstem reflex caused by stimulation of the trigeminal nerve, which results in bradycardia, hypotension, and asystole. TCR can occur during any neurosurgical procedure. Initially, it is managed via the immediate removal of the stimulus from the trigeminal nerve. If asystole persists after intravenous atropine or glycopyrrolate, chest compression or transcutaneous cardiac pacing may be considered. The authors present the first case of TCR that was successfully managed with transcutaneous cardiac pacing. OBSERVATIONS: A 51-year-old man presented with aneurysmal subarachnoid hemorrhage. Although he had no history of cardiac disease and there were no abnormal findings on electrocardiography, transient asystole due to TCR occurred during craniotomy. The patient's heart rate spontaneously recovered after the immediate discontinuation of the procedure. The authors completed aneurysm clipping with transcutaneous cardiac pacing because intravenous atropine was not effective in preventing TCR. There were no complications associated with intraoperative asystole or transcutaneous cardiac pacing, and the patient was discharged without neurological deficits. LESSONS: TCR can be appropriately managed with the immediate discontinuation of intraoperative procedures. Furthermore, transcutaneous cardiac pacing may be considered for persistent TCR with poor response to intravenous atropine or glycopyrrolate.

Physiological changes in circulating mannose levels in normal, glucose-intolerant, and diabetic subjects.

Mannose is an essential hexose that is required for glycoprotein synthesis. Although circulating mannose levels are known to be influenced by metabolic disorders, how physiological levels of mannose fluctuate in normal and diabetic subjects is largely unknown. We describe a new accurate and sensitive assay for determining circulating mannose levels, which we used to measure plasma mannose levels in 273 normal and diabetic (DM) subjects. Our results revealed a clear correlation (r = 0.754) between fasting plasma mannose (FPM) and fasting plasma glucose (FPG) levels. Our mannose assay showed sensitivity and specificity comparable to that seen for hemoglobin A(1c) (HbA(1c)) assay in subjects with impaired glucose tolerance (IGT) or DM whose FPG levels were normal. Mannose levels were found to increase less than glucose levels in response to an oral glucose tolerance test (OGTT). Furthermore, plasma mannose levels did not significantly change following a meal and more closely correlated with the coefficient of variation (CV) of daily glucose levels than did glucose itself. In conclusion, the close correlation between FPM and FPG levels taken together with the small fluctuations seen in plasma mannose in response to glucose suggests that the measurement of mannose using our assay could potentially play a supplementary role in the diagnosis and screening of patients with mild DM.

Fairly marked enantioselectivity for the hydrolysis of amino acid esters by chemically modified enzymes.

The hydrolysis (deacylation) of enantiomeric substrates by the chemically modified enzymes decanoyl-alpha-chymotrypsin and decanoyl-trypsin was studied. Reaction activity for decanoyl-alpha-chymotrypsin was lower than that for the native enzyme, although intriguingly the enantioselectivity was markedly enhanced as compared with the native enzyme. In particular, the apparently complete enantioselective catalysis was attained for the hydrolytic cleavage of p-nitrophenyl N-dodecanoyl-D(L)-phenylalaninates. The enhancement of enantioselectivity, however, was not observed for decanoyl-trypsin. These results suggest that the chemically modified alpha-chymotrypsin by addition of hydrophobic groups has promoted enantioselectivity for the hydrolysis of hydrophobic esters.

Catalytic specificity exhibited by p-sulfonatocalix[n]arenes in the methanolysis of N-acetyl-l-amino acids.

Specific acid catalysis of p-sulfonatocalix[n]arenes (n = 4, Calix-S4; n = 6, Calix-S6; n = 8, Calix-S8) was observed in the alcoholysis of N-acetyl-l-amino acids in methanol. The methanolysis rates of basic amino acid substrates (His, Lys, and Arg) were markedly enhanced in the presence of Calix-Sn, as compared with rates observed with p-hydroxybenzenesulfonic acid (pHBS), which is a noncyclic analogue of Calix-Sn. This catalytic effect of Calix-Sn was not observed for the methanolysis of Phe, Tyr, and Trp substrates. On the other hand, (1)H NMR experiments following the effect of Calix-Sn on N-acetyl-l-amino acid substrates in CD(3)OD showed that the spectrum of a mixture of the His substrate with Calix-Sn was significantly different from the combined spectra of the respective compounds. These changes in spectra support the formation of an inclusion complex of Calix-Sn with basic amino acids. Furthermore, it was obvious that methanolysis of the His substrate catalyzed by Calix-S4 and Calix-S6 obeyed Michaelis-Menten kinetics. These results indicate that the catalytic activity of Calix-Sn originates from its forming a complex with specific substrates (basic amino acids), similar to enzymatic reactions.