We examined the movement of an actin filament sliding on a mixture of normal and genetically modified myosin molecules that were attached to a glass surface. For this purpose, we used a Dictyostelium ...G680V mutant myosin II whose release rates of Pi and ADP were highly suppressed relative to normal myosin, leading to a significantly extended life-time of the strongly bound state with actin and virtually no motility. When the mixing ratio of G680V mutant myosin II to skeletal muscle HMM (heavy myosin) was 0.01%, the actin filaments moved intermittently. When they moved, their sliding velocities were about two-fold faster than the velocity of skeletal HMM alone. Furthermore, sliding movements were also faster when the actin filaments were allowed to slide on skeletal muscle HMM-coated glass surfaces in the motility buffer solution containing G680V HMM. In this case no intermittent movement was observed. When the actin filaments used were copolymerized with a fusion protein consisting of Dictyostelium actin and Dictyostelium G680V myosin II motor domain, similar faster sliding movements were observed on skeletal muscle HMM-coated surfaces. The filament sliding velocities were about two-fold greater than the velocities of normal actin filaments. We found that the velocity of actin filaments sliding on skeletal muscle myosin molecules increased in the presence of a non-motile G680V mutant myosin motor.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this study, we investigated the role of leptin and its receptors (Ob-R) in profibrogenic responses in the liver using Zucker (fa/fa) rats, a natural occurring Ob-R-deficient animal.
Male Zucker ...(fa/fa) rats and their lean (+/?) littermates were given intraperitoneal injections of thioacetamide (TAA) (200 mg/kg body wt, 3 times/wk) for 4–8 weeks, and progression of hepatic fibrosis was evaluated. In vitro transactivation of hepatic stellate cells (HSCs) isolated from Zucker rats was evaluated by Western blotting and immunocytochemistry for α-smooth muscle actin and type I collagen. Further, a long-form Ob-R (Ob-Rb) in sinusoidal endothelial cells (SECs) and Kupffer cells was identified by reverse-transcription polymerase chain reaction. Moreover, transforming growth factor (TGF)-β1. messenger RNA in LSE cells, a human SEC-derived cell line, was measured by Northern blotting.
Although the normal liver does not produce leptin, activated HSCs produced leptin in vivo during fibrogenesis caused by TAA. In Zucker rats, TAA-induced hepatic fibrosis was prevented almost completely, whereas induction of TGF-β1 and activation of HSCs were abolished. It is less likely, however, that leptin plays an essential role in the activation of HSCs as a strong autocrine regulator, because HSCs isolated from Zucker rats undergo normal transactivation process in vitro. In contrast, SECs and Kupffer cells contain Ob-Rb, through which leptin up-regulates the expression of matrix remodeling genes including TGF-β1.
Collectively, these findings indicated that leptin and its functional receptors (Ob-Rb) play a pivotal role in profibrogenic responses in the liver.
The movements of single actin filaments along a myosin-fixed glass surface were observed under a conventional fluorescence microscope. Although random at a low concentration, moving directions of ...filaments were aligned by the presence of over 1.0 mg/mL of unlabeled filaments. We found that actin filaments when at the intermediate concentrations ranging from 0.1 to 1.0 mg/mL, formed winding belt-like patterns and moved in a two-directional manner along the belts. These patterns were spread over a millimeter range and found to have bulged on the glass in a three-dimensional manner. Filaments did not get closer than about 37.5 nm to each other within each belt-pattern. The average width and the curvature radius of the pattern did not apparently change even when the range of actin concentrations was between 0.05 and 1.0 mg/mL or the sliding velocity between 1.2 and 3.2 μm/sec. However, when the length of filaments was shortened by ultrasonic treatments or the addition of gelsolin molecules, the curvature radius became small from 100 to 60 μm. These results indicate that this belt-forming nature of actin filaments may be due to some inter-filament interactions.
Background: Early detection of dementia will be important for implementation of disease-modifying treatments in the near future. We aimed to investigate the diagnostic validity and reliability of the ...Japanese version of the revised Addenbrooke's Cognitive Examination (ACE-R J) for identifying mild cognitive impairment (MCI) and dementia. Methods: We translated and adapted the original ACE-R for use with a Japanese population. Standard tests for evaluating cognitive decline and dementing disorders were applied. A total of 242 subjects (controls = 73, MCI = 39, dementia = 130) participated in this study. Results: The optimal cut-off scores of ACE-R J for detecting MCI and dementia were 88/89 (sensitivity 0.87, specificity 0.92) and 82/83 (sensitivity 0.99, specificity 0.99) respectively. ACE-R J was superior to the Mini-Mental State Examination in the detection of MCI (area under the curve (AUC): 0.952 vs. 0.868), while the accuracy of the two instruments did not differ significantly in identifying dementia (AUC: 0.999 vs. 0.993). The inter-rater reliability (ICC = 0.999), test-retest reliability (ICC = 0.883), and internal consistency (Cronbach's α = 0.903) of ACE-R J were excellent. Conclusion: ACE-R J proved to be an accurate cognitive instrument for detecting MCI and mild dementia. Further neuropsychological evaluation is required for the differential diagnosis of dementia subtypes.
In this study, we investigated hepatic fibrogenesis caused by long-term thioacetamide (TAA) administration in ob/ob mice, a naturally occurring leptin deficient animal. In the lean littermates, ...prominent hepatic fibrosis, as well as positive staining for α smooth muscle actin (α-SMA), was induced by treatment with TAA (200 μg/g, IP, 3 times per week) for 4 to 8 weeks as expected. In sharp contrast, almost no hepatic fibrosis developed in ob/ob mice given the equivalent doses of TAA, where specific staining for α-SMA barely was detected. Induction of α1(I) procollagen mRNA caused by TAA also was prevented in ob/ob mice almost completely. Further, transforming growth factor β (TGF-β) mRNA was increased in the liver after TAA treatment for 4 weeks in lean littermates, which also was prevented in ob/ob mice. Interestingly, fibrotic septa in the hepatic lobules, as well as increases in α1(I) procollagen mRNA, was observed in ob/ob mice, when they were injected with recombinant murine leptin (1 μg/g daily) in combination with TAA treatment. Leptin
per se did not cause any fibrotic changes in the liver in ob/ob mice. These findings clearly indicated that leptin deficiency is responsible for the resistance to TAA-induced profibrogenic responses in ob/ob mice. In conclusion, leptin appears to promote profibrogenic responses in the liver, in part, by up-regulation of TGF-β. (H
EPATOLOGY 2002;36:12-21.)
Depressive symptoms are common in patients with Alzheimer's disease (AD) and increase the caregiver burden, although the etiology and pathologic mechanism of depressive symptoms in AD patients remain ...unclear. In this study, we tried to clarify the cerebral blood flow (CBF) correlates of subjective depressive symptoms in AD.
Seventy-six consecutive patients with AD were recruited from outpatient units of the Memory Clinic of Okayama University Hospital. Subjective depressive symptoms were evaluated using the short version of the Geriatric Depression Scale (GDS). All patients underwent brain SPECT with 99mTc-ethylcysteinate dimer, and the SPECT images were analyzed by the Statistical Parametric Mapping 8 program.
No significant differences between groups with high and low GDS scores were found with respect to age, sex, years of education, and revised Addenbrooke's Cognitive Examination scores. Compared to patients with low scores on GDS, patients with high scores showed significant hypoperfusion in the left inferior frontal region.
The left inferior frontal region may be significantly involved in the pathogenesis of subjective depressive symptoms in AD. Subjective and objective depressive symptoms may have somewhat different neural substrates in AD.
Background: The frontal assessment battery (FAB) is reported to be a useful tool for assessing frontal dysfunction. However, the neural substrates involved in patients with Alzheimer's disease (AD) ...remain to be elucidated. The aim of the present study was to identify the regional perfusion patterns of the brain associated with performance scores on the FAB of patients with AD using brain perfusion assessed by single photon emission computed tomography (SPECT). Methods: Twenty-four AD patients with high scores and 24 age- and sex-matched AD patients with low scores on the FAB were selected from 470 consecutive Japanese patients of the Memory Clinic of Okayama University Hospital. All 48 participants underwent brain SPECT with 99mTc-ethylcysteinate dimer, and the SPECT images were analyzed by statistical parametric mapping. Results: No significant differences were found between high and low FAB scoring groups with respect to Addenbrooke's Cognitive Examination scores, Mini-Mental State Examination scores, or the depression score of the Neuropsychiatric Inventory subscale. Compared with patients with high scores on the FAB, AD patients with low scores showed significant hypoperfusion in the left middle frontal gyrus (MFG) and the right superior frontal gyrus (SFG) extending to the left SFG. Conclusion: Our results suggest that functional activity of the SFG and MFG is closely related to the FAB score. The FAB might be a promising strategy to detect early stages of AD with low SFG and MFG function.
Low‐dose blonanserin was effective for treating severe delusions in six patients with various types of dementia, and it was also well tolerated. Delusion and hallucination scores, as measured by the ...Neuropsychiatric Inventory, improved, and extrapyramidal symptom scores, as measured by the Drug‐Induced Extrapyramidal Symptoms Scale, were unchanged. Blonanserin has strong dopamine D2 receptor‐, 5‐hydroxytryptamine 2A receptor‐, and dopamine D3 receptor‐blocking activities and weak 5‐hydroxytryptamine‐2C, α1‐, histamine H1‐, and muscarinic M1‐blocking activities. Its unique characteristics may make it suitable for treating severe delusions and hallucination in patients with dementia.
Oligomerization of a peptide was attempted in a flow reactor that simulated a submarine hydrothermal system. When fluid containing glycine repeatedly circulated through the hot and cold regions in ...the reactor, oligopeptides were made from glycine. When divalent ions (such as copper ions) were added under acidic conditions, oligoglycine was elongated up to hexaglycine. This observation suggests that prebiotic monomers could have oligomerized in the vicinity of submarine hydrothermal vents on primitive Earth.
Aim
Artificial nutrition, including tube feeding, continues to be given to dementia patients in numerous geriatric facilities in Japan. However, the clinical characteristics of patients receiving ...artificial nutrition have not been fully investigated. Therefore, we tried to evaluate the clinical features of those patients in this study.
Methods
Various clinical characteristics of all inpatients at 18 of 20 psychiatric hospitals in Okayama Prefecture, Japan, with a percutaneous endoscopic gastrostomy tube, nasogastric tube, or total parenteral nutrition were evaluated.
Results
Two hundred twenty‐one patients (5.4% of all inpatients) had been receiving artificial nutrition for more than 1 month, and 187 (130 women, 57 men; 84.6% of 221 patients) were fully investigated. The mean age was 78.3 years old, and the mean duration of artificial nutrition was 29.8 months. Eighty‐four patients (44.7% of 187 patients) were receiving artificial nutrition for more than 2 years. Patients with Alzheimer's disease (n = 78) formed the biggest group, schizophrenia (n = 37) the second, and vascular dementia (n = 26) the third.
Conclusion
About one‐fifth of the subjects receiving artificial nutrition were in a vegetative state. More than a few patients with mental disorders, including schizophrenia, also received long‐term artificial nutrition. We should pay more attention to chronic dysphasia syndrome in mental disorders.
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