Enzymes as Green Catalysts for Precision Macromolecular Synthesis.

The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.

Acute Poststroke Depression Is Associated with Thalamic Lesions and Clinical Outcomes: A Case-Control Study.

BACKGROUND: We investigated the role of acute-phase stroke lesions and patient characteristics in poststroke depression (PSD) and its effect on the clinical outcome. PATIENTS AND METHODS: Five and 30 days after admission, 175 patients self-reported their depressive symptoms on the Patient Health Questionnaire-9. We compared the clinical characteristics and outcomes in patients with (n = 41) and without PSD (n = 134). Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS); the modified Rankin Scale (mRS) was used to determine the functional outcome. RESULTS: There was no significant difference between patients with and without PSD in the age, gender ratio, lesion side, and the history of hypertension, diabetes mellitus, alcohol and tobacco use, and previous stroke. Thalamic lesions were significantly associated with PSD (P = .03), although there was no significant difference in both the NIHSS score and the final mRS score of patients with thalamic lesions. Backward stepwise logistic regression analysis showed that a higher NIHSS score and thalamic lesions were independent predictors of PSD. Total hospitalization was significantly longer in patients with PSD. At the time of admission, the NIHSS score was significantly higher in patients who developed moderate to severe PSD than in those with mild PSD or without PSD. CONCLUSIONS: PSD in the acute phase was associated with thalamic lesions and severe stroke. Hospitalization was significantly longer in patients with PSD and their functional disability was more severe, suggesting that PSD played a role in the unsatisfactory results of poststroke rehabilitation.

Adenosine A1 receptors measured with 11 C-MPDX PET in early Parkinson's disease.

Adenosine A1 receptors (A1 Rs) interact negatively with dopamine D1 receptors (D1 Rs) in neurons of the basal ganglia's direct pathway, while adenosine A2A receptors (A2A Rs) negatively interact with dopamine D2 receptors (D2 Rs) in indirect-pathway neurons. The aim of this study was to investigate the cerebral density of A1 Rs in Parkinson's disease (PD) in its early stages, using PET scans with the radioligand 8-dicyclopropylmethyl-1-11 C-methyl-3-propylxanthine (11 C-MPDX). We studied 10 drug-naïve patients with early PD. Each patient was also examined for dopamine transporters (DATs) and D2 Rs by PET using 11 C-2-ß-carbomethoxy-3-ß-(4-fluorophenyl)-tropane (11 C-CFT) and 11 C-raclopride (11 C-RAC), respectively. Ten elderly, healthy volunteers were recruited as controls for 11 C-MPDX PET scanning and eight elderly volunteers were recruited as controls for 11 C-CFT and 11 C-RAC PET scanning. The PET scans revealed a decrease in the uptake ratio index (URI) of 11 C-CFT and an increase in the URI of 11 C-RAC in patients. In the temporal lobe, the binding potential for 11 C-MPDX was higher in the patient group than in healthy subjects, but not in the other regions examined, including the striatum. In patients, we observed motor-symptom asymmetry and a relationship between parkinsonism and the striatal density of DATs, but not A1 R density. In the putamen of early PD, asymmetrical down-regulation of A2A Rs is likely a compensatory mechanism in response to a decrease in dopamine. However, our study suggests that A1 Rs are unaltered in the putamen of early PD.

Retrograde suction decompression of a large internal carotid aneurysm using a balloon guide catheter combined with a blood-returning circuit and STA-MCA bypass: a technical note.

It is difficult to treat large internal carotid aneurysms with simple surgical clipping. Here, we present a retrograde suction decompression (RSD) procedure for large internal carotid aneurysms using a balloon guide catheter combined with a blood-returning circuit and a superficial temporal artery to middle cerebral artery (STA-MCA) bypass.All patients underwent an STA-MCA bypass before the temporary occlusion of the internal carotid artery (ICA). A 6-French sheath was inserted into the common carotid artery (CCA), and a 6-French Patrive balloon catheter was placed into the ICA 5 cm past the bifurcation. Aneurysm exposure was obtained; temporary clips were placed on the proximal M1, A1, and posterior communicating (Pcom) segments; and an extension tube was then connected to the balloon catheter. A three-way stopcock was placed, and aspiration was performed through the device to collapse the aneurysm. The aspirated blood was returned to a venous line with an added heparin to prevent anemia after aspiration. During the decompression, the blood flow to the cortical area was supplied through the STA-MCA bypass. After the aneurysm collapse, the surgeon carefully dissected the perforating artery from the aneurysm dome or neck, and permanent clips were then placed on the aneurysm neck. Our procedure has several advantages, such as STA-MCA bypass without external carotid artery occlusion for preventing ischemic complications of the cortical area, anemia may be avoided because of the return of the aspirated blood, and a hybrid operation room is not required to perform this method.

Olfactory preservation during anterior interhemispheric approach for anterior skull base lesions: technical note.

Anosmia is not a rare complication of surgeries that employ the anterior interhemispheric approach. Here, we present a fibrin-gelatin fixation method that provides reinforcement and moisture to help preserve the olfactory nerve when using the anterior interhemispheric approach and describe the results and outcomes of this technique. We analyze the outcomes with this technique in 45 patients who undergo surgery for aneurysms, brain tumors, or other pathologies via the anterior interhemispheric approach. Anosmia occurred in 4 patients (8.8%); it was transient in 2 (4.4%) and permanent in the remaining 2 (4.4%). Brain tumors clearly attached to the olfactory nerve were resected in the patients with permanent anosmia. We found a significant difference in the presence of anosmia between patients with or without lesions that were attaching the olfactory nerve (p = 0.011). Our results suggested that fibrin-gelatin fixation method can reduce the reported risk of anosmia. However, the possibility of olfactory nerve damage is relatively high when operating on brain tumors attaching olfactory nerve.

[Prospective Study of the Causes of Limb Numbness in Patients with Diabetes].

PURPOSE: Many patients with diabetes mellitus (DM) experience numbness in the extremities. This DM neuropathy may be complicated by peripheral entrapment neuropathy. We prospectively investigated the cause(s) of limb numbness in DM patients. MATERIALS AND METHODS: We enrolled 23 patients with uni- or bilateral limb numbness who were treated in our DM clinic. They were 10 men and 13 women; their average age was 63 years. The average duration of their neurological symptoms was 28.3 months. RESULTS: Numbness was located in the upper limb in 7 patients, the lower limb in 11, and both the upper and lower limbs in 5. Among the 12 patients with upper-limb numbness, 9 manifested carpal tunnel syndrome and one each cervical OPLL or cervical spondylosis. Of the 16 cases of lower limb numbness, 10 were attributable to tarsal tunnel syndrome, 7 to lumbar spinal disease, 3 to restless leg syndrome, 2 to piriformis syndrome, and 1 to peroneal nerve entrapment neuropathy. CONCLUSIONS: In 21 of the 23 patients with uni- or bilateral limb numbness, the cause was attributable to several kinds of etiology such as entrapment neuropathy. Consequently, other treatable peripheral nerve disorders, e.g. tarsal tunnel syndrome, must be considered when diagnosing DM patients with limb numbness. Our findings suggest that therapeutic intervention to address such diseases will affect the quality of life of DM patients with limb numbness.

Differential effects of age on human striatal adenosine A1 and A(2A) receptors.

The aim of this study was to investigate the effect of age on the distribution of adenosine A1 receptors (A1Rs) and adenosine A(2A) receptors (A(2A)Rs) in the striatum of healthy subjects using PET imaging with 8-dicyclopropylmethyl-1-[¹¹C]methyl-3-propylxanthine ([¹¹C]MPDX) and [7-methyl-¹¹C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine ([¹¹C]TMSX), respectively. We recruited 8 young (22.0 ± 1.7 years) and 10 elderly (65.4 ± 7.6 years) volunteers to undergo [¹¹C]MPDX PET scanning, and 11 young (22.7 ± 2.7 years) and six elderly (60.7 ± 8.5 years) volunteers to undergo [¹¹C]TMSX PET scanning. A dynamic series of decay-corrected PET scans was performed for 60 min following injection of [¹¹C]MPDX or [¹¹C]TMSX. We calculated the binding potential (BP(ND) ) of [¹¹C]MPDX and distribution volume ratio (DVR) of [¹¹C]TMSX in the striatum. The BP(ND) of [¹¹C]MPDX was significantly lower in elderly than in young subjects, both in the putamen and head of the caudate nucleus. The BP(ND) was negatively correlated with age in both the putamen and the head of the caudate nucleus. However, no difference was found between the DVR of [¹¹C]TMSX in the striata of young and elderly subjects, nor was there a correlation between age and the DVR of [¹¹C]TMSX. The effect of age on the distribution of A1Rs in the human striatum described herein is similar to previous reports of age-related decreases in dopamine D1 and D2 receptors. Unlike A1Rs, however, this study suggests that the distribution of A(2A) Rs does not change with age.

Biobased polymers: synthesis of graft copolymers and comb polymers using lactic acid macromonomer and properties of the product polymers.

For developing broader application of biobased polymers, graft copolymers and comb polymers having poly(lactic acid) (PLA) side chains have been synthesized by using a macromonomer technique. PLA macromonomers (MMm) having a methacryloyl polymerizable group with different PLA chain length with an average length m = 4, 6, 8, 12, 18, and 30 were prepared via ring-opening polymerization of l-lactide using hydroxyethyl methacrylate (HEMA) initiator catalyzed by Sn(Oct)(2). Radical polymerization behaviors of these macromonomers were examined. Radical copolymerization of MMm (m = 4, 6, and 8), with vinyl monomers like n-butyl methacrylate (BMA) and n-butyl acrylate (BA) in water as the reaction medium, gave stable miniemulsions of poly[n-butyl (meth)acrylate-graft-lactic acid]s [PB(M)A-g-PLAm]. MMm with m value higher than 12, however, gave aggregate products in a minor amount besides miniemulsions in a major amount, producing not a stable emulsion system of graft copolymers. The solution copolymerization, on the other hand, produced a wider variety of the graft copolymers, where a wider range of MMm (even m ≥ 12) can be employed. In a 1,4-dioxane solution, the radical copolymerization of MMm with BMA and methyl methacrylate (MMA) gave various graft copolymers [PB(M)MA-g-PLAm]. A new type of comb polymers (PMMm) having PLAm as pendant side chains were obtained by radical homopolymerization of MMm in a 1,4-dioxane solution. The graft copolymers and comb polymers obtained here are amorphous. Physical properties of the polymers from miniemulsions suggested them to be applicable for coatings or elastic materials which are environmentally desirable as a new class of biobased polymers. In addition, the present approach provided fundamental information on relationships between the length of PLA side chain and the bulk properties of the product polymers.

Preoperative liquid embolization of cerebeller hemangioblastomas using N-butyl cyanoacrylate.

INTRODUCTION: We aim to present and discuss clinical outcomes of preoperative liquid embolization of hemangioblastomas (HB) using N-butyl cyanoacrylate (NBCA). METHODS: From 1999 through 2010, 19 patients presenting with symptoms of vertigo and/or headaches were diagnosed with HB based on preoperative magnetic resonance imaging and cerebral angiographic findings at our institution. Preoperative embolization with NBCA was performed on tumors in 10 of 21 operations for 19 patients. For each of these patients, the lesion was pathologically confirmed as HB. RESULTS: Embolization had a favorable outcome in all patients. No permanent neurological complications were observed after preoperative embolization using NBCA. However, thalamic infarction and minor hemorrhage were observed in two patients with cerebellar HB. CONCLUSION: The authors recommend NBCA as an embolization material for large cerebellar HB.

Superficial temporal arteriovenous fistula as a complication of rhytidectomy.

A 67-year-old woman who had undergone rhytidectomy 5 years before her presentation experienced increasing pulsatile tinnitus on the left side that had begun 2 years earlier. Angiography revealed a direct arteriovenous fistula between the superficial temporal artery and superficial temporal vein in front of her left ear. There was a scar from the earlier cosmetic surgery at the site. The fistula was embolized with N-butyl cyanoacrylate, and her tinnitus disappeared. We posit that the fistula was a complication of rhytidectomy and that a small arteriovenous fistula formed at the time of surgery and enlarged over time. This case indicates that arteriovenous fistulae can occur as a delayed complication of cosmetic surgery.

Preparation of pH-Responsive Poly(γ-glutamic acid) Hydrogels by Enzymatic Cross-Linking.

pH-responsive hydrogels are important for oral drug release applications, and they are increasingly demanded to reduce the adverse side effects of drug release and improve drug absorption. In this study, a new type of pH-responsive hydrogel comprised of poly(γ-glutamic acid) modified with tyramine (PGA-Tyr) was developed through enzymatic cross-linking in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). The gelation rate, stiffness, swelling behavior, and pore size of the resulting hydrogels were tuned by changing the concentrations of HRP and H2O2 or the degree of substitution (DS) of PGA-Tyr. The pH responsiveness of the hydrogels was evaluated by the swelling ratio in solutions with various pH values, and their pH responsiveness exhibited a good reversibility in pH 2.0 and 7.0 solutions. The degradation rate of the hydrogels in simulated intestinal fluid (SIF) was faster than that in simulated gastric fluid (SGF). Moreover, indomethacin (IM), a hydrophobic drug model, was encapsulated in the hydrogels by rapid in situ gelation, and the pH-dependent drug release of IM-loaded hydrogels was achieved in SGF and SIF. Importantly, when IM was entrapped in pluronic F-127 to form drug micelles, the burst release of the IM-micelle-loaded hydrogels with a high DS of PGA-Tyr was remarkably decreased in SGF, and sustained drug release was presented in SIF. Thus, pH-responsive PGA-based hydrogels have tremendous promise for biomedical applications, especially oral drug delivery.

Radial artery grafts for symptomatic cavernous carotid aneurysms in elderly patients.

BACKGROUND: Radial artery grafts (RAG) have been used in the treatment of complex vascular lesions, but not for symptomatic cavernous carotid aneurysms in elderly patients. AIM: To investigate the safety, usefulness, and perioperative complications of RAGs for symptomatic cavernous carotid aneurysms in elderly patients. MATERIAL AND METHODS: Of the 74 consecutive patients, in whom RAGs were used, we retrospectively investigated the postoperative outcomes and complications in eight elderly patients aged over 70 years with symptomatic internal carotid artery aneurysms in cavernous sinus. RESULTS: Postoperative complications included one case of cerebral infarction, one case of symptomatic seizures, and one case of delayed cranial nerve palsy. OUTCOME: Seven patients had an mRS score of 0, and one patient had a score of 2. Postoperatively there was improvement in cranial nerve palsy in seven patients and the patients who had symptoms for one year and eight months had residual deficits. Although it cannot be stated that the frequency of perioperative complications was low, the final outcomes were favorable. CONCLUSION: Even in carotid disease that is difficult to treat among the elderly, RAG would appear to be a useful and safe treatment.

[Treatment of spontaneous spinal epidural hematoma].

OBJECTIVE: Spontaneous spinal epidural hematoma (SSEH) is rare. There was not enough information about diagnosis and treatment of SSEH, although they require emergency surgery and some surgeons may hesitate to use alternative treatments. We report our six cases SSEH and discuss treatment of SSEH from the literature. MATERIALS AND METHODS: We encountered six cases of SSEH. They were 4 female and 2 male cases and age ranged from 61 to 75 years (averaging 67.3 years). The SSEH were located in the cervical (n=3), cervicothoracic (n=3) regions. In 4 cases, there were hematomas at the right side of the spinal epidural space, and 2 cases were at the left side. RESULTS: All cases experienced severe neck or shoulder pain. In five cases, hemiparesis was noted. Cervical MRI showed that epidural hematoma had compressed the spinal cord posterolateraly. In all cases, cervical CT scans also revealed epidural hematoma, too. Five cases were operated on by removal of the hematoma with hemilaminectomy and one case was operated on with laminectomy because of severe paresis. The mean time since the start of the operation was 11 hours (ranging from 7 to 20 hours). Only one case who had only severe pain without paresis was treated conservatively. All except two patients completely recovered neurologically. The two cases continued to have sensory disturbance. CONCLUSIONS: We successfully treated 6 cases of SSEH. MRI is useful for diagnosis of SSEH, and CT scan can also diagnose it as in our cases. Cases with severe neurological deficit would be considered as needing surgical treatment at an appropriate time and the cases without neurological deficit should be kept under observation until surgery becomes necessary.

Lipase-catalyzed oligomerization and hydrolysis of alkyl lactates: direct evidence in the catalysis mechanism that enantioselection is governed by a deacylation step.

Lipase-catalyzed oligomerization of alkyl d- and l-lactate monomers (RDLa and RLLa, respectively) was studied for the first time. It has been found that the oligomerization occurs enantioselectively only for d-lactates to give oligomers up to heptamers of lactic acid (LA) in good to high yields by using primary C1 to C8 alkyl groups and sec-butyl group for d-lactate monomers. No reaction happened for all l-lactates in similar conditions. Lipase-catalyzed hydrolysis of alkyl d- and l-lactates was also examined, revealing that the hydrolysis took place for both d- and l-lactates, although l-lactates proceeded a couple of times slower. The hydrolysis results clearly demonstrate that the lipase catalysis mechanism involves an acyl-enzyme intermediate (EM) formation via the acylation step from both d- and l-lactates as a rate-determining step, and the subsequent deacylation step, a nucleophilic attack of water to the EM, takes place to produce free LA. On the other hand, in the oligomerization of d-lactates, the deacylation step, in which a sec-alcohol group of the monomer or of the propagating chain-end attacks to the EM, is only allowed for the sec-d-alcohol group to give a one-LA-unit-elongated oligomer. l-Lactates form the EM; however, the subsequent deacylation reaction with both the sec-l- and sec-d-alcohol groups does not take place, failing in the oligomerization to occur. These results provide with the first direct evidence in the lipase catalysis that the enantioselection is governed by the deacylation step. In the co-oligomerization between l- and d-lactates, the l-isomer retarded the reaction rate of the d-isomer, which was found due to the function of the former as a competitive inhibitor in the acylation step toward the latter.

Lipase-catalyzed polyester synthesis--a green polymer chemistry.

This article is a short comprehensive review describing in vitro polyester synthesis catalyzed by a hydrolysis enzyme of lipase, most of which has been developed for these two decades. Polyesters are prepared by repeated ester bond-formation reactions; they include two major modes, ring-opening polymerization (ROP) of cyclic monomers such as cyclic esters (lactones) and condensation polymerization via the reaction between a carboxylic acid or its ester group and an alcohol group. Polyester synthesis is, therefore, a reaction in reverse way of in vivo lipase catalysis of ester bond-cleavage with hydrolysis. The lipase-catalyzed polymerizations show very high chemo-, regio-, and enantio-selectivities and involve various advantageous characteristics. Lipase is robust and compatible with other chemical catalysts, which allows novel chemoenzymatic processes. New syntheses of a variety of functional polyesters and a plausible reaction mechanism of lipase catalysis are mentioned. The polymerization characteristics are of green nature currently demanded for sustainable society, and hence, desirable for conducting 'green polymer chemistry'.

Biobased polymer system: miniemulsion of poly(alkyl methacrylate-graft-lactic acid)s.

To broaden the application scope of lactic acid polymers, a new miniemulsion of poly(alkyl methacrylate-graft-lactic acid)s has been developed. The graft copolymer synthesis was based on a poly(lactic acid) macromonomer having a methacryloyl polymerizable group. The macromonomer and a comonomer of n-butyl methacrylate together with a suitable surfactant formed a miniemulsion of the comonomers in water. A radical copolymerization of the comonomers took place to produce the graft copolymer as a stable miniemulsion. The copolymer showed elastic polymer properties. The miniemulsion system may find useful applications as a new biobased polymer material that is environmentally desirable.

Treatment of cervical OPLL by cervical anterior fusion using autologous vertebral bone grafts.

BACKGROUND: In anterior fusion, we use autologous bone grafts from cervical vertebral bodies and bioabsorptive screws to prevent graft extrusion (Williams-Isu method). We report the application of and indication for the Williams-Isu method for OPLL and present our clinical and radiological results. METHODS: Using the Williams-Isu method, we treated 17 patients with cervical OPLL; 15 had segmental- and 2 had continuous-type OPLL. The median follow-up term was 24 months. The patients underwent anterior decompression and fusion at a single level (n = 8) or at two levels (n = 9). As a control, 17 patients with cervical spondylosis underwent anterior single-level decompression and fusion using the Williams-Isu method. Pre- and postoperative radiographs of the cervical spine were obtained in all patients, and the alignment of the whole cervical and fused segment and the height of the fused segment were compared. RESULTS: All but one patient experienced alleviation of clinical symptoms without deterioration during the follow-up period. The recovery rate on the JOA score was 71.7%. The patient with continuous-type OPLL suffered postoperative neurological deterioration because of a remnant of the upper-level OPLL. Radiological studies confirmed the absence of bone graft dislocation and fracture, and of satisfactory bone fusion in all patients. There was no significant difference between the two patient groups with respect to whole spine alignment and the alignment and height of the fused segment. CONCLUSIONS: The Williams-Isu method is useful for treating not only cervical spondylosis but also cervical segmental OPLL at one or two levels.

[Cerebral salt wasting syndrome and traumatic vasospasm after head trauma: report of two cases].

While patients with cerebral salt wasting syndrome and traumatic cerebral arterial spasms have been reported, the underlying pathogenesis of these events remains unclear. We encountered 2 patients with head trauma and cerebral infarction who presented with cerebral salt-wasting syndrome and cerebral arterial spasms. Our findings suggested hypothalamic dysfunction due to venous congestion around the hypothalamus caused cerebral salt wasting syndrome and traumatic cerebral arterial spasms.

The Ivy Sign on Fluid Attenuated Inversion Recovery Images Related to Single-Photon Emission Computed Tomography Cerebral Blood Flow in Moyamoya Disease: A Case Report.

Moyamoya disease is an idiopathic progressive cerebrovascular steno-occlusive disorder characterized by the formation of numerous collaterals called Moyamoya vessels. Accurate evaluation of vascular status and cerebral blood flow (CBF) is needed for prompt treatment to prevent ischemic and/or hemorrhagic events. The pathogenesis of the ivy sign on fluid attenuated inversion recovery (FLAIR) images of Moyamoya disease patients is unclear. We report a Moyamoya disease case wherein the ivy sign changed in relation to single-photon emission computed tomography (SPECT)-measured CBF during progression and following treatment. A 49-year-old female presented with slight aphasia and right hemiparesis. Magnetic resonance imaging (MRI) diffusionweighted image revealed cerebral infarction in the left frontal lobe. Cerebral angiography images showed bilateral distal internal carotid artery stenosis and Moyamoya vessels. FLAIR images exhibited the ivy sign. We performed superficial temporal arteryâ€" middle cerebral artery (STA-MCA) bypass surgery with encephalogaleosynangiosis (EGS) and encephalomyosynangiosis (EMS) on the left side 6 months after first presentation. After operation, left-side resting CBF gradually improved on SPECT and the ivy sign decreased. On the other hand, right-side CBF gradually deteriorated at rest, and the ivy sign increased. Therefore, we performed STAâˆ'MCA bypass with EGS and EMS on the right side 4 years after first presentation. After the operation, the resting CBF increased and the ivy sign decreased. The FLAIR ivy sign may be a useful indicator of both deterioration and improvement of CBF status without the need for CBF imaging using contrast material.