Identification of epicardial connections can improve the success rate of first-pass right pulmonary vein isolation.

Background: Epicardial connections between the right pulmonary vein (PV) and the right atrium have been reported. Objective: The purpose of this study was to evaluate the usefulness of our new pulmonary vein isolation (PVI) strategy with identification of these epicardial connections. Methods: Overall, 235 patients with atrial fibrillation were included. High-density mapping of the left atrium was performed to identify the earliest activation sites (EASs) before PVI in all patients. With our new strategy, if EASs around the right PV carina were identified, we ablated these sites and performed usual first-pass circumferential PVI. The patients were divided into 2 groups according to the ablation strategy. One hundred fifteen patients underwent first-pass PVI without information on EASs (nonanalyzed group), and 78 patients underwent ablation at EASs around the right PV carina in addition to PVI (analyzed group). After first-pass ablation around the PV antrum, remapping was performed. Results: High-density mapping before PVI showed that the prevalence of EASs around the right PV carina was 10.9% in all patients (9.6% in the nonanalyzed group, 12.8% in the analyzed group; P = .74. The first-pass right PVI success rate was higher in the analyzed group than in the nonanalyzed group (93.6% vs 82.6%; P = .04). The radiofrequency application time for PVI was significantly shorter in the analyzed group than in the nonanalyzed group (45.6 ± 1.0 minutes vs 51.2 ± 0.9 minutes; P <.05). Conclusion: Identification of epicardial connections before ablation could improve the success rate of first-pass right PVI.

Streamlined workflow including nurse recognition of conjugate gaze deviation for reduced door-to-puncture time in endovascular thrombectomy: A retrospective study.

BACKGROUND: Endovascular thrombectomy is recognized as a pivotal treatment for acute ischemic stroke due to large vessel occlusion. Prolonged door-to-puncture time correlates with decreased patient independence after acute ischemic stroke. This study aimed to assess whether a streamlined workflow, including nurse recognition of conjugate gaze deviation, could reduce door-to-puncture time in endovascular thrombectomy. METHODS: This study retrospectively reviewed patients with acute ischemic stroke who underwent endovascular thrombectomy between March 2017 and March 2022 and compared a previous workflow with a streamlined workflow implemented in April 2019. In the streamlined workflow, nurses recognized conjugate gaze deviation to identify patients with large vessel occlusions and played a more active role in reducing the door-to-puncture time. We compared time metrics and outcomes, including recanalization status, parenchymal hemorrhage type 2, and favorable outcomes (modified Rankin Scale score 0-2) at three months between the previous and streamlined workflow groups. RESULTS: After the application of the streamlined workflow, the door-to-puncture time was reduced from 76 min to 68 min (p = 0.014), and the number of patients with a door-to-puncture time of less than 60 min increased (15% vs. 36%, p = 0.002). Outcomes including modified thrombolysis in cerebral infarction ≥ 2b (73% vs. 71%, p = 1.000), parenchymal hemorrhage type 2 (7% vs. 2%, p = 0.281), and favorable outcome (33% vs. 34%, p = 1.000) were comparable between the two groups. CONCLUSION: Nurse recognition of conjugate gaze deviation contributed to an 8-minute reduction in the door-to-puncture time, demonstrating the potential benefits of an organized workflow in acute ischemic stroke.

Molecular functions of the double-sided and inverted ubiquitin-interacting motif found in Xenopus tropicalis cryptochrome 6.

Cryptochromes (CRYs) are multifunctional molecules that act as a circadian clock oscillating factor, a blue-light sensor, and a light-driven magnetoreceptor. Cry genes are classified into several groups based on the evolutionary relationships. Cryptochrome 6 gene (Cry6) is present in invertebrates and lower vertebrates such as amphibians and fishes. Here we identified a Cry6 ortholog in Xenopus tropicalis (XtCry6). XtCRY6 retains a conserved long N-terminal extension (termed CRY N-terminal extension; CNE) that is not found in any CRY in the other groups. A structural prediction suggested that CNE contained unique structures; a tetrahelical fold structure topologically related to KaiA/RbsU domain, overlapping nuclear- and nucleolar-localizing signals (NLS/NoLS), and a novel motif (termed DI-UIM) overlapping a double-sided ubiquitin-interacting motif (DUIM) and an inverted ubiquitin-interacting motif (IUIM). Potential activities of the NLS/NoLS and DI-UIM were examined to infer the molecular function of XtCRY6. GFP-NLS/NoLS fusion protein exogenously expressed in HEK293 cells was mostly observed in the nucleolus, while GFP-XtCRY6 was observed in the cytoplasm. A glutathione S-transferase (GST) pull-down assay suggested that the DI-UIM physically interacts with polyubiquitin. Consistently, protein docking simulations implied that XtCRY6 DI-UIM binds two ubiquitin molecules in a relationship of a twofold rotational symmetry with the symmetry axis parallel or perpendicular to the DI-UIM helix. These results strongly suggested that XtCRY6 does not function as a circadian transcriptional repressor and that it might have another function such as photoreceptive molecule regulating light-dependent protein degradation or gene expression through a CNE-mediated interaction with ubiquitinated proteins in the cytoplasm and/or nucleolus.

Endovascular treatment of an aneurysm arising from the minor limb of an upper basilar artery fenestration: illustrative case.

BACKGROUND: An aneurysm arising in an upper basilar artery (BA) fenestration is extremely rare. The authors reported a case involving successful endovascular treatment of an aneurysm arising from the minor limb of an upper BA fenestration. OBSERVATIONS: A 65-year-old woman presented with an incidentally detected upper BA aneurysm arising from the minor limb of an upper BA fenestration. The irregularly shaped aneurysm was 6.0 × 2.7 mm in diameter, and the minor limb had several perforators. The aneurysm was nearly completely occluded with a catheter-assisted technique. The authors preserved both limbs of the BA fenestration. The postoperative course was uneventful, and the patient had an excellent clinical course with no neurological deficits or aneurysmal recanalization. LESSONS: The case is the first report of an unruptured aneurysm arising at the minor limb of an upper BA fenestration. In this case, the authors preserved the minor limb with endovascular treatment. The authors believe catheter-assisted coil embolization to be a feasible endovascular technique in such cases.

Fibrosis-4 index reflects right ventricular function and prognosis in heart failure with preserved ejection fraction.

AIMS: Fibrosis-4 index (FIB-4 index), calculated by age, aspartate aminotransferase, alanine aminotransferase, and platelet count, is a simple marker to evaluate liver fibrosis and is associated with right-sided heart failure. However, the clinical relevance of FIB-4 in patients with heart failure with preserved ejection fraction (HFpEF) remains unclear. We investigated the prognostic implication of the FIB-4 index regarding right ventricular dysfunction in patients with HFpEF. METHODS AND RESULTS: This prospective study included 116 consecutive HFpEF patients (mean age 79 years, 43% male) hospitalized with acute decompensated heart failure. We evaluated the association of the FIB-4 index with right ventricular function determined by tricuspid annular plane systolic excursion (TAPSE) and tricuspid lateral annular systolic velocity (S') before discharge. Cox regression analysis was performed to evaluate the association between the FIB-4 index and major adverse cardiovascular events (MACE) defined as the composite of cardiovascular death, readmission for heart failure, nonfatal myocardial infarction, and nonfatal stroke. FIB-4 index before discharge was significantly lower than that at admission (2.62 [1.92-3.46] and 3.03 [2.05-4.67], median [interquartile range], P < 0.001). Left ventricular ejection fraction, TAPSE, and S' before discharge were 62.7 (55.9-68.6) %, 17.5 ± 4.6 mm (mean ± standard deviation), and 10.0 (8.0-12.0) cm/s, respectively. In multiple linear regression analysis, the FIB-4 index before discharge was inversely correlated with TAPSE (ß minus;0.244, P = 0.014) and S' (ß -0.266, P = 0.009). During a median follow-up of 736 days, 37 MACE occurred. Multivariate Cox regression analysis revealed that a high FIB-4 index before discharge (per 1 point) was a significant predictor of MACE (hazard ratio 1.270, 95% confidence interval 1.052-1.532) after adjustment for male, serum creatinine, and haemoglobin. Receiver operating characteristic analysis indicated that the optimal cut-off value of FIB-4 index before discharge to predict MACE was 3.11. Kaplan-Meier survival analysis showed that patients with a FIB-4 index before discharge ≥3.11 had a significantly poorer prognosis than patients with FIB-4 index before discharge <3.11 (P = 0.029). Patients with an FIB-4 index ≥3.11 had a 2.202-fold (95% confidence interval 1.110-4.368) increased risk of MACE compared with those with an FIB-4 index <3.11 after adjustment for male, serum creatinine, and haemoglobin. CONCLUSIONS: An increase in the FIB-4 index was associated with right ventricular dysfunction and a higher risk of future MACE in patients with HFpEF.

Possible Protective Effect of Remote Ischemic Preconditioning on Acute Kidney Injury Following Elective Percutaneous Coronary Intervention: Secondary Analysis of a Multicenter, Randomized Study.

Remote ischemic preconditioning (RIPC) is a promising strategy for protecting against ischemic reperfusion injury. This study is a secondary analysis of a randomized study that aimed to evaluate the effect of RIPC on the early increase in serum creatinine (SCr) following percutaneous coronary intervention (PCI), which is associ-ated with contrast-induced acute kidney injury. Patients with stable angina undergoing elective PCI were assigned to control, RIPC, and continuous infusion of nicorandil (nicorandil) groups. The endpoint of this study was the incidence of the early increase in SCr, a predictor of contrast-induced acute kidney injury, which was defined as either a > 20% or absolute increase by 0.3 mg/dl of SCr levels after 24 h of PCI. This study included 220 patients for whom a dataset of SCr values was available. The incidence of the early increase in SCr was significantly lower in the RIPC than in the control (1.3% vs 10.8%, p = 0.03) group, but was not significantly different between the nicorandil and control groups. In multivariate analysis, RIPC remained a significant fac-tor associated with a reduction in the incidence of early increase in SCr. RIPC reduces the incidence of early increase in SCr in patients with stable angina following elective PCI.

Current status of a helicopter transportation system on remote islands for patients undergoing mechanical thrombectomy.

BACKGROUND: Mechanical thrombectomy (MT) is standard treatment for acute ischemic stroke (AIS) with large-vessel occlusion within 6 h of symptom onset to treatment initiation (OTP). Recent trials have extended the therapeutic time window for MT to within 24 h. However, MT treatment remains low in remote areas. Nagasaki Prefecture, Japan has many inhabited islands with no neurointerventionalists. Our hospital on the mainland is a regional hub for eight island hospitals. We evaluated clinical outcomes of MT for patients with AIS on these islands versus on the mainland. METHODS: During 2014-2019, we reviewed consecutive patients with AIS who received MT at our hospital. Patients comprised the Islands group and Mainland group. Patient characteristics and clinical outcomes were compared between groups. RESULTS: We included 91 patients (Islands group: 15 patients, Mainland group: 76 patients). Seven patients (46.7%) in the Islands group versus 43 (56.6%) in the Mainland group achieved favorable outcomes. Successful recanalization was obtained in 11 patients (73.3%) on the islands and 67 (88.2%) on the mainland. The median OTP time in the Islands was 365 min. In both the Islands and Mainland groups, the OTP time and successful recanalization were associated with functional outcome. The modified Rankin Scale (mRS) score at 90 days ≤2 was obtained in two patients and mRS = 3 in four patients among eight patients with OTP time >6 h. CONCLUSIONS: Few patients with AIS on remote islands have received MT. Although patients who underwent MT on the islands had longer OTP, the clinical outcomes were acceptable. OTP time on remote islands must be shortened, as this is related to functional outcome. In some cases with successful recanalization, a favorable outcome can still be obtained even after 6 h. Even if OTP exceeds 6 h, it is desirable to appropriately select patients and actively perform MT.

[Task-shifting Carried out by an Emergency Department's Stroke Hotline and Medical Care Support Conducted by Nurse Practitioners].

Our hospital serves as the main hub for eight remote island hospitals(RIHs)in Nagasaki Prefecture, Japan. The shortage of stroke physicians, which has led to overwork, is a major concern. Several "task-shifting" systems were adopted to avoid physician burnout. First, the emergency department established a hotline system for receiving emergency calls regarding a stroke, and which managed initial care until the stroke physicians arrived(called the Nagasaki Medical Center stroke hotline system: N-SHOT)in 2014. The rt-PA administration rate increased from 3.3% in the Pre-N-SHOT group to 6.7% in the N-SHOT group. Second, the 'isolated islands stroke hotline system(I-SHOT)', with which physicians in RIHs participate in cooperation with N-SHOT, was started in 2017. After I-SHOT was introduced, the number of patients treated with the drip and ship method using teleradiology and 24-h helicopter transportation increased from 20(2010-2016)to 29 cases in 2017-2018. Additionally, new information and communication technology(ICT)using smart devices was introduced into the teleradiology system for task support. Third, on behalf of stroke physicians, nurse practitioners(NP)helped bedridden patients who had been delivered from RIHs and who had received acute treatment, and returned to their islands by helicopter or airplane as transitions of care. N-SHOT is smoothly operated by each hospital department without reducing the quality of the stroke hotline. It has contributed to an increase in rt-PA and mechanical thrombectomy cases; I-SHOT has had the same effect. Task-shifting and task support with N- & I-SHOT, the smooth transfer system by NP, and the new ICT are considered to be useful for reducing the overall burden of stroke physicians.

Rapid Oxidation Following Photoreduction in the Avian Cryptochrome4 Photocycle.

Avian magnetoreception is assumed to occur in the retina. Although its molecular mechanism is unclear, magnetic field-dependent formation and the stability of radical-containing photointermediate(s) are suggested to play key roles in a hypothesis called the radical pair mechanism. Chicken cryptochrome4 (cCRY4) has been identified as a candidate magnetoreceptive molecule due to its expression in the retina and its ability to form stable flavin neutral radicals (FADH●) upon blue light absorption. Herein, we used millisecond flash photolysis to investigate the cCRY4 photocycle, in both the presence and absence of dithiothreitol (DTT); detecting the anion radical form of FAD (FAD●-) under both conditions. Using spectral data obtained during flash photolysis and UV-visible photospectroscopy, we estimated the absolute absorbance spectra of the photointermediates, thus allowing us to decompose each spectrum into its individual components. Notably, in the absence of DTT, approximately 37% and 63% of FAD●- was oxidized to FADOX and protonated to form FADH●, respectively. Singular value decomposition analysis suggested the presence of two FAD●- molecular species, each of which was destined to be oxidized to FADOX or protonated to FADH●. A tyrosine neutral radical was also detected; however, it likely decayed concomitantly with the oxidation of FAD●-. On the basis of these results, we considered the occurrence of bifurcation prior to FAD●- generation, or during FAD●- oxidization, and discussed the potential role played by the tyrosine radical in the radical pair mechanism.

[Endovascular Treatment of a Ruptured Aneurysm of the Right Vertebral Artery with an Aberrant Right Subclavian Artery].

We report a rare case of the endovascular treatment of a ruptured aneurysm of the right vertebral artery with an aberrant right subclavian artery(ARSA). A 60-year-old woman was urgently admitted because of consciousness disturbance. Brain CT showed subarachnoid hemorrhage, and CT angiography showed a right vertebral ruptured aneurysm. Endovascular treatment of the aneurysm was performed via a transfemoral approach. During the endovascular treatment, the right subclavian artery was found to diverge from the descending aorta on the periphery of the left subclavian artery. An ARSA was detected, and the right vertebral artery(VA)originated from the ARSA. The guiding catheter was passed through the right VA via an ARSA, and the aneurysm was completely embolized. The patient was transferred to another hospital on day 44 without any motor weakness. To our knowledge, this is the first case of an ARSA with a ruptured aneurysm in the right VA for which endovascular treatment was successfully performed via the ARSA. In patients with an ARSA or aberrant left subclavian artery, the artery could merge with Kommerell's diverticulum(KD)at its origin and be histologically fragile. Thus, in patients with an ARSA, attention should be paid to catheterization to avoid injuring the KD. CT angiography of the aortic arch might be considered before endovascular treatment.

Efficacy of the Drip and Ship Method in 24-h Helicopter Transportation and Teleradiology for Isolated Islands.

Our hospital, located on the mainland, serves as a hub center for nine hospitals on the remote islands of Nagasaki Prefecture, Japan. There are no stroke specialists on these islands. We can transfer emergency patients from these islands to our hospital at any time, using a teleradiology system and three types of helicopter transport. We examined the efficacy of the drip and ship (DS) method for treating patients with acute ischemic stroke (AIS) on these islands, in comparison with patients on the mainland. From 2010 to 2017, we reviewed 98 consecutive patients with AIS who received intravenous recombinant tissue plasminogen activator (IV rt-PA) in our hospital or were transported to our hospital after IV rt-PA. Patients were divided into the Islands group (received IV rt-PA on the islands, DS; 31 cases) and the Mainland group (67 cases). The median transport distance from the islands was 112 km. The rate of patients achieving favorable outcomes was 54.8% in the Islands group and 64.2% in the Mainland group, with no significant differences. Multivariate analysis revealed that patients living on isolated islands did not have increased risks of unfavorable outcomes. Endovascular therapy (EVT), as part of the drip, ship, and retrieve method, was performed in 22.6% of patients in the Islands group and EVT in 38.8% of those in the Mainland group. The DS method seems feasible and safe for patients living on isolated islands with the use of 24-h helicopter transportation and teleradiology.

Serum malondialdehyde-modified low-density lipoprotein levels on admission predict prognosis in patients with acute coronary syndrome undergoing percutaneous coronary intervention.

BACKGROUND: Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is a predictive marker of cardiovascular events in patients with stable angina pectoris. However, little is known about this marker in patients with acute coronary syndrome (ACS). We investigated the prognostic relevance of MDA-LDL to cardiovascular outcomes in patients with ACS. METHODS: A total of 370 consecutive patients with ACS who underwent primary percutaneous coronary intervention (PCI) were enrolled from October 2009 to September 2014 at Mitoyo General Hospital. Serum MDA-LDL levels were measured at admission. The patients were divided into three tertile groups according to serum MDA-LDL levels. The primary outcomes were cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, revascularization, and heart failure requiring hospital admission. RESULTS: MDA-LDL levels in patients with acute myocardial infarction were significantly greater than those in patients with unstable angina pectoris (mean±standard deviation: 133±48U/L vs. 157±69U/L, p=0.001). During follow-up [472 (195-920) days], 82 (22%) events occurred. Kaplan-Meier analysis showed that patients in the highest MDA-LDL tertile had the worst prognosis (log-rank, p<0.001). Cox regression analysis showed that serum MDA-LDL levels were an independent predictor of cardiovascular events after PCI in patients with ACS, even after adjustment for age, sex, body mass index, conventional cardiovascular risk factors, other lipid biomarkers, statin use on admission, cardiac biomarkers, and presence or absence of multivessel disease (hazard ratio: 1.80 per 1 standard deviation U/L increase, 95% confidence interval: 1.07-3.16, p=0.027). CONCLUSION: Serum MDA-LDL levels on admission are a significant prognostic marker in patients with ACS who undergo successful PCI.

Thyroid Storm Precipitated by Diabetic Ketoacidosis and Influenza A: A Case Report and Literature Review.

A 46-year-old woman with a history of Graves' disease presented with the chief complaints of appetite loss, weight loss, fatigue, nausea, and sweating. She was diagnosed with diabetic ketoacidosis (DKA), thyroid storm, and influenza A. She was treated with an intravenous insulin drip, intravenous fluid therapy, intravenous hydrocortisone, oral potassium iodine, and oral methimazole. As methimazole-induced neutropenia was suspected, the patient underwent thyroidectomy. It is important to maintain awareness that thyroid storm and DKA can coexist. Furthermore, even patients who have relatively preserved insulin secretion can develop DKA if thyroid storm and infection develop simultaneously.

[A Case of Ruptured Internal Carotid-Posterior Communicating Artery Aneurysm Associated with Acute Subdural Hematoma, Extending from the Interhemispheric Space to the Posterior Fossa].

A 69-year-old woman was admitted to our hospital because of a sudden severe headache without a history of head trauma. CT and MRI revealed an acute subdural hematoma (ASDH) extending from the right interhemispheric space to the posterior fossa bilaterally, with a small amount of subarachnoid hemorrhage that was predominantly localized to the left side of the basal cistern. CT angiogram demonstrated a long protruding ruptured aneurysm at the junction of the right internal carotid and posterior communicating arteries (IC/PC AN) with a posteroinferior projection, associated with a small bleb located near the tentorial edge close to the ipsilateral posterior clinoid process, for which she received clipping surgery. Though rare, IC/PC AN could cause pure or nearly pure ASDH in the above-mentioned distribution. Therefore, in patients with such ASDH, especially without a history of head injury or precise information regarding the situation at the time of onset, urgent imaging evaluation and early intervention are essential to prevent devastating re-rupture events.

An increase in the coronary calcification score is associated with an increased risk of heart failure in patients without a history of coronary artery disease.

BACKGROUND: The presence of coronary artery calcification (CAC) and its severity predict future cardiovascular events and is used for risk stratification. However, the association of CAC with heart failure (HF) in patients without a history of coronary artery disease (CAD) remains unclear. This study aimed to determine the correlations of CAC with N-terminal pro-B-type natriuretic peptide (NT-proBNP) and HF events in patients without a history of CAD or HF. METHODS: From June 2010 to June 2013, a total of 487 patients without a history of CAD and HF were enrolled. All of the patients underwent plane multi-detector computed tomography. They were divided into four categories according to CAC scores: ≤10, 11-100, 101-400, and ≥401. RESULTS: The proportion of patients with high NT-proBNP levels increased with CAC categories (p<0.0001). The CAC score was associated with NT-proBNP levels ≥400pg/ml, with an odds ratio of 2.901 (95% confidence interval: 1.368-6.151, p=0.0055) for CAC scores ≥401 compared with CAC scores of 0-10 after adjustment for confounding factors. During the follow-up period of 497±315 days, nine patients were admitted for HF. Kaplan-Meier analysis showed that patients with CAC scores ≥401 had a lower rate of freedom from admission for HF with cumulative incidences of 0.4%, 1%, 2%, and 8% for CAC scores of 0-10, 11-100, 101-400, and ≥401, respectively (p<0.0001). Increasing CAC scores were associated with an increase in incidence of admission for HF, with a hazard ratio of 10.371 for CAC scores ≥401 (95% CI: 1.062-101.309, p=0.0443) compared with CAC scores of 0-10 after adjustment for risk factors. CONCLUSION: Severe CAC is an independent determinant of high NT-proBNP levels and a predictor of admission for HF in a population without a history of CAD or HF.

Serum cystatin C level is associated with left atrial enlargement, left ventricular hypertrophy and impaired left ventricular relaxation in patients with stage 2 or 3 chronic kidney disease.

BACKGROUND: Cystatin C is an endogenous marker of kidney function that overcomes the limitations of serum creatinine. High serum cystatin C levels have been associated with increased cardiovascular mortality and morbidity. In this cross-sectional study, we aimed to determine the associations between serum cystatin C levels and structural and functional cardiac changes in patients with stage 2 or 3 chronic kidney disease (CKD). METHODS AND RESULTS: We enrolled 429 consecutive patients (aged 24-97 years) with CKD stage 2 or 3 and left ventricular (LV) ejection fraction (LVEF)>40%. Echocardiographic parameters, including LV mass index (LVMI), early diastolic mitral annulus velocity (e' velocity), left atrial volume index (LAVI), and N-terminal of the prohormone brain natriuretic peptide (NT-proBNP) were measured. Patients were categorized into quartiles according to serum cystatin C levels. Cystatin C was associated with LAVI (p=0.0055), LVEF (p=0.0432), LVMI (p=0.0409), e' (p=0.0051), E/e' (p=0.0027), and log-transformed NT-proBNP (p<0.0001) according to multivariate linear regression analysis, after adjustment for confounding factors including creatinine-based estimated glomerular filtration rate (eGFRcreat) and urinary albumin to creatinine ratio. Incidence of eccentric and concentric hypertrophy increased with increasing cystatin C (Q1, 38%; Q2 49%; Q3, 51%; Q4, 66%, p=0.0008), mainly because of increasing concentric hypertrophy (Q1, 30%; Q2, 39%; Q3, 39%; Q4, 51%, p=0.0187). CONCLUSION: A high serum cystatin C is strongly associated with structural cardiac abnormalities such as LVH and left atrial enlargement, impaired LV relaxation, and an increased NT-proBNP, independently of eGFRcreat in patients with stage 2 or 3 CKD.

Structural elements responsible for the glucosidic linkage-selectivity of a glycoside hydrolase family 13 exo-glucosidase.

Glycoside hydrolase family 13 contains exo-glucosidases specific for α-(1→4)- and α-(1→6)-linkages including α-glucosidase, oligo-1,6-glucosidase, and dextran glucosidase. The α-(1→6)-linkage selectivity of Streptococcus mutans dextran glucosidase was altered to α-(1→4)-linkage selectivity through site-directed mutations at Val195, Lys275, and Glu371. V195A showed 1300-fold higher kcat/Km for maltose than wild-type, but its kcat/Km for isomaltose remained 2-fold higher than for maltose. K275A and E371A combined with V195A mutation only decreased isomaltase activity. V195A/K275A, V195A/E371A, and V195A/K275A/E371A showed 27-, 26-, and 73-fold higher kcat/Km for maltose than for isomaltose, respectively. Consequently, the three residues are structural elements for recognition of the α-(1→6)-glucosidic linkage.

Analysis of risk factors associated with complications of hyperbaric oxygen therapy.

PURPOSE: The aim of this study was to verify independent risk factors of pressure equalization problems associated with hyperbaric oxygen (HBO(2)) therapy. METHODS: We reviewed a single-institutional study of 1609 patients with 17604 treatments who had HBO(2) therapy in a multiplace chamber, in which the factors examined and their relationship to complications were assessed, using multivariate analyses, to determine the significantly independent risk factors of complications related to HBO(2) therapy. RESULTS: The compression rate was 0.067 atmospheres absolute/min (6.8 kPa/min). Pressure equalization problems of the middle ear, expressed as pain or discomfort, such as cranial sinus pain, and teeth pain were observed in 156 patients (9.7%). Sixty-six of them could not continue HBO(2) therapy because of these problems. Peripheral circulatory disorders with refractory ulcers or nonhealing wounds and the interval between clinical symptoms and the first day of HBO(2) therapy were independent risk factors of pressure equalization problems. Independent risk factors of cessation due to pressure equalization problems were identified as age more than 61 years, female sex, and interval between symptoms and the first day of HBO(2) therapy. CONCLUSION: It is suggested that chamber compression must be performed with particular care when patients have peripheral circulatory disorders and have short interval between clinical symptoms and the first day of HBO(2) therapy.