Knockout of ykcB, a Putative Glycosyltransferase, Leads to Reduced Susceptibility to Vancomycin in Bacillus subtilis.

Vancomycin resistance of Gram-positive bacteria poses a serious health concern around the world. In this study, we searched for vancomycin-tolerant mutants from a gene deletion library of a model Gram-positive bacterium, Bacillus subtilis, to elucidate the mechanism of vancomycin resistance. We found that knockout of ykcB, a glycosyltransferase that is expected to utilize C55-P-glucose to glycosylate cell surface components, caused reduced susceptibility to vancomycin in B. subtilis. Knockout of ykcB altered the susceptibility to multiple antibiotics, including sensitization to ß-lactams and increased the pathogenicity to silkworms. Furthermore, the ykcB-knockout mutant had (i) a decreased amount of lipoteichoic acid, (ii) decreased biofilm formation, and (iii) an increased content of diglucosyl diacylglycerol, a glycolipid that shares a precursor with C55-P-glucose. These phenotypes and vancomycin tolerance were abolished by knockout of ykcC, a gene in the same operon with ykcB probably involved in C55-P-glucose synthesis. Overexpression of ykcC enhanced vancomycin tolerance in both the parent strain and the ykcB-knockout mutant. These findings suggest that ykcB deficiency induces structural changes of cell surface molecules depending on the ykcC function, leading to reduced susceptibility to vancomycin, decreased biofilm formation, and increased pathogenicity to silkworms. IMPORTANCE Although vancomycin is effective against Gram-positive bacteria, vancomycin-resistant bacteria are a major public health concern. While the vancomycin-resistance mechanisms of clinically important bacteria such as Staphylococcus aureus, Enterococcus faecium, and Streptococcus pneumoniae are well studied, they remain unclear in other Gram-positive bacteria. In the present study, we searched for vancomycin-tolerant mutants from a gene deletion library of a model Gram-positive bacterium, Bacillus subtilis, and found that knockout of a putative glycosyltransferase, ykcB, caused vancomycin tolerance in B. subtilis. Notably, unlike the previously reported vancomycin-resistant bacterial strains, ykcB-deficient B. subtilis exhibited increased virulence while maintaining its growth rate. Our results broaden the fundamental understanding of vancomycin-resistance mechanisms in Gram-positive bacteria.

Deposits on Retinal Surface Seen on OCT in Ocular Amyloidosis.

PURPOSE: To investigate the tomographic features in patients with hereditary amyloidosis transthyretin (hATTR). DESIGN: Retrospective case series and analysis of B-scan OCT images. PARTICIPANTS: A total of 120 patients (240 eyes) diagnosed with hATTR. METHODS: We performed a retrospective review of the treatment history and retrospective analysis of the OCT images of patients with hATTR. The parameters analyzed were the age at which the last OCT was performed, presence of ocular amyloidosis, history of pars plana vitrectomy (PPV), systemic treatment, and genetic mutations. Two independent evaluators evaluated the OCT images for characteristic needle-shaped pattern deposits on the retinal surface, and a third evaluator resolved any differences in their evaluations. MAIN OUTCOME MEASURES: The frequency of characteristic needle-shaped deposits on the retinal surface seen on OCT. RESULTS: The mean age at the time of the last OCT was 56.5 ± 14.9 years. Ninety-nine patients had gene encoding transthyretin (TTR) with the Val30Met mutation, and 21 patients had other mutations. Of 240 eyes, 128 had signs of ocular amyloidosis. Fifty of 73 eyes (68.5%) with a history of PPV for vitreous opacities exhibited characteristic deposits on OCT. Four of 31 eyes with vitreous opacity but without a history of PPV showed deposits on the retinal surface. No eyes without a history of vitreous opacities revealed the characteristic needle-shaped deposits. CONCLUSIONS: Characteristic needle-shaped deposits on the retinal surface seen on OCT are significant because they are seen in most of the vitrectomized eyes presenting with ocular amyloidosis.

Cerebral circulation in aging.

Cerebral circulation is known to be protected by the regulatory function against the hypoperfusion that will affect the cognitive function as a result of brain ischemia and energy failure. The regulatory function includes cerebrovascular autoregulation, chemical control, metabolic control, and neurogenic control, and those compensatory mechanisms can be influenced by hypertension, atherosclerosis, cardiac diseases, cerebrovascular diseases and aging. On the other hand, large and/or small infarction, intracranial hemorrhage, subarachnoid hemorrhage, atherosclerosis, amylod angiopathy are also more directly associated with cognitive decline not only in those with vascular cognitive impairment or vascular dementia but also those with Alzheimer's disease.

High prevalence of gastroesophageal reflux disease in Parkinson's disease: a questionnaire-based study.

The aim of this study is to investigate the frequency and clinical features of gastroesophageal reflex disease (GERD) in Parkinson's disease (PD). Consecutively recruited PD patients and controls were questioned about heartburn and GERD with a questionnaire. In PD patients, disease duration and severity, quality of life, and nonmotor symptoms were also examined and then the clinical features of GERD were analyzed. A total of 102 patients and 49 controls were enrolled and 21 patients and 4 controls had heartburn, significantly frequent in PD. The prevalence rate of GERD was 26.5% in PD and the odds ratio was 4.05. Heartburn, bent forward flexion, and wearing-off phenomenon were frequent, and scores of UPDRS, total and part II, PD questionnaire-39, and nonmotor symptom scale were significantly higher in PD patients with GERD than without GERD. Multiple logistic regression analysis revealed statistical significance in UPDRS part II and nonmotor symptom scale. This study suggests that GERD is prevalent in PD. Deterioration of daily living activities and other nonmotor symptoms can imply the presence of GERD. Because clinical symptoms of GERD are usually treatable, the management can improve the patient's quality of life. Increased attention should be given to detect GERD in PD.

Cerebrovascular lesions in elderly Japanese patients with Alzheimer's disease.

OBJECTIVE: Cerebrovascular lesions (CVLs) are known to play important roles in the pathophysiology underlying Alzheimer's disease (AD), especially in elderly AD cases. The present study was conducted to elucidate the relationship between the CVLs and vascular risk factors (VRFs) in elderly Japanese patients with AD. SUBJECTS AND METHODS: The CVLs such as lacunar infarcts, old microbleeds (OMBs), white matter lesions (WMLs), and occlusive vascular lesions on MRI were analyzed in relation to the risk factors in 120 Japanese patients with probable AD. Their mean age was 75.6 years. The subjects were divided into two age groups: young-old group (YOG) consisting of 55 cases being younger than 75 years and old-old group (OOG) consisting of 65 cases being 75 years or older. RESULTS: In overall analysis, 10 cases (8.3%) showed brain atrophy without CVLs on MRI, 46 cases (38.3%) showed WMLs in addition to the brain atrophy, 61 cases (50.8%) showed lacunar lesions, and 3 cases (2.5%) were diagnosed as having a superficial siderosis. Lacunar infarcts and OMBs were more frequently observed in OOG than in YOG, and were also more frequently observed in those with 2 or more VRFs than those with less than 2 VRFs (p<0.05). The WMLs were more pronounced in OOG, and in those with more VRFs. CONCLUSION: The CVLs including lacunes, WMLs, and OMBs were present more than 90% of elderly Japanese patients with AD. As the severity of CVLs was associated with VRFs and age, VRFs may modify clinical presentation of elderly AD patients.

Effects of yokukansan on behavioral and psychological symptoms of vascular dementia: an open-label trial.

Previous clinical trials suggest that the traditional Japanese medicine yokukansan has beneficial effects on the behavioral and psychological symptoms of dementia (BPSD). The present study was conducted to elucidate the efficacy of yokukansan on BPSD in patients with vascular dementia. Thirteen Japanese patients (9 men and 4 women) who were diagnosed as having vascular dementia (VaD) according to the diagnostic criteria of NINDS-AIREN were subjected to the open-label clinical trial in which yokukansan (7.5g/day) has been given for 4 weeks. Their mean age was 71.2±6.5 years. The BPSD was evaluated using the Neuropsychiatric Inventory (NPI), cognitive function was evaluated by the Mini-Mental State Examination (MMSE), the activities of daily living was evaluated by Barthel index (BI) and Disability Assessment for Dementia (DAD), and the extrapyramidal signs were evaluated by United Parkinson's Disease Rating Scale (UPDRS). The mean NPI was 33.0±17.3 and 23.6±13.9 for the baseline and after treatment, respectively. It was significantly improved after treatment (p<0.05). In the NPI-subcategories, there was a significant improvement in agitation and disinhibition after the treatment. There was no significant change in MMSE, BI, DAD or UPDRS before and after the treatment. There was no adverse effect during the treatment period. The present results suggest that yokukansan is beneficial for the treatment of BPSD in VaD patients.

Inhibition of the PI3 kinase/Akt pathway enhances doxorubicin-induced apoptotic cell death in tumor cells in a p53-dependent manner.

Constitutive activation of the PI3 kinase/Akt pathway is associated with the neoplastic phenotype of a large number of human tumor cells. As the anti-apoptotic role of the PI3 kinase/Akt pathway has been established, we have examined whether specific blockade of this pathway sensitizes tumor cells to DNA-damaging agent-induced cytotoxicity by enhancing apoptotic cell death. Although a PI3 kinase inhibitor, LY294002, by itself does not induce apoptotic cell death, LY294002 selectively and markedly enhances the apoptosis-inducing efficacy of doxorubicin: such an enhanced cell death is only detected in tumor cells in which the PI3 kinase/Akt pathway is constitutively activated, and it is totally dependent on the functional p53 pathway. These results suggest that the combination of a PI3 kinase/Akt pathway inhibitor and doxorubicin provides an efficient chemotherapeutic strategy for the treatment of tumor cells in which the PI3 kinase/Akt pathway is constitutively activated and the p53 pathway is functional.

Novel dysferlin mutations and characteristic muscle atrophy in late-onset Miyoshi myopathy.

Miyoshi myopathy is characterized by weakness of the calf muscles during early adulthood. We report a case of late-onset Miyoshi myopathy presenting at 48 years of age, with novel mutations in the dysferlin gene. Muscle computed tomography clearly revealed severe atrophy in the soleus and medial gastrocnemius muscles. Even older patients with atrophy in the posterior compartment of the distal lower extremities and a relatively high serum creatine kinase level should be examined for the dysferlin gene.