Antioxidant effects of a dietary supplement: Reduction of indices of oxidative stress in normal subjects by water-soluble chitosan

The effect of water-soluble chitosan, a natural polymer derived from chitin, on indices of oxidative stress was investigated in normal volunteers. Treatment with chitosan for 4 weeks produced a significant decrease in levels of plasma glucose, atherogenic index and led to increase in high density lipoprotein cholesterol (HDL). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity (TPA). There was good correlation between TPA and oxidized albumin ratio. The results indicate that oxidized albumin ratio represents a potentially useful marker of oxidative stress. In in vitro studies, albumin carbonyls and hydroperoxides were significantly decreased in a time-dependent manner in the presence of chitosan, compared with controls (p < 0.05). Chitosan also reduced two stable radicals in a dose- and time-dependent manner. The results suggest that chitosan has a direct antioxidant activity in systemic circulation by lowering the indices of oxidative stress in both in vitro and in vivo studies. This may confer benefits additional to the reduction in plasma carbohydrate and increase in HDL levels. It may also inhibit oxidation of serum albumin commonly observed in patients undergoing hemodialysis, resulting in reduction of oxidative stress associated with uremia.     

Assessing multidimensional cognitions of drinking among alcohol-dependent patients: development and validation of a drinking-related cognitions scale (DRCS)

The aim of this study is to develop and validate the Drinking-Related Cognitions Scale (DRCS). The DRCS is a brief measure designed to assess multidimensional cognitions of drinking, including perception of drinking problems, perception of impaired drinking control, readiness to change, decisional balancing, and self-efficacy in alcohol-dependent patients. This study was carried out in Japan, with 132 alcohol-dependent patients (mean age (SD): 49.4 (7.5) years) admitted to an inpatient treatment program. On the basis of prior studies of the rating scales of drinking-related cognitions, DRCS items were selected. Factor analysis was carried out to assess the selection of DRCS items and the factor structure. The factor analysis of the 15 DRCS items showed three factors, "expectancy and resignation," "perception of impaired control," and "perception of drinking problem." The DRCS showed good reliability (Cronbach's alpha-coefficients for the entire scale and subscales were 0.80 or higher, and the analysis of variance intraclass correlation coefficient for the test-retest method was 0.81 for the total score). The total DRCS and subscale scores predicted abstinence status at a 3-month follow-up, and the DRCS was considered to have satisfactory predictive validity. It was suggested that the DRCS would be useful for the easy measurement of multidimensional cognitions of drinking in alcohol-dependent patients.     

Physiology and dynamics of uric acid in hyperuricemia

Gout is a type of inflammatory arthritis that is triggered by the crystallization of monosodium urate (MSU) within the joints and is often associated with hyperuricemia. Further understanding the physiology and dynamics of uric acid in human is required to make sure the disease mechanism of both gout and hyperuricemia in clinic. The amount of urate in the body consists urate pool, and which depends on the balance between dietary intake, synthesis, and excretion. Uric acid is a weak acid that exists largely as MSU, the ionized form, in urate pool at physiologic pH. But the solubility of MSU is influenced of pH, temperature and protein of blood and tissue.     

A novel beta-myosin heavy chain gene mutation, p.Met531Arg, identified in isolated left ventricular non-compaction in humans, results in left ventricular hypertrophy that progresses to dilation in a mouse model

Mutations in the betaMHC (beta-myosin heavy chain), a sarcomeric protein are responsible for hypertrophic and dilated cardiomyopathy. However, the mechanisms whereby distinct mutations in the betaMHC gene cause two kinds of cardiomyopathy are still unclear. In the present study we report a novel betaMHC mutation found in a patient with isolated LVNC [LV (left ventricular) non-compaction] and the phenotype of a mouse mutant model carrying the same mutation. To find the mutation responsible, we searched for genomic mutations in 99 unrelated probands with dilated cardiomyopathy and five probands with isolated LVNC, and identified a p.Met531Arg mutation in betaMHC in a 13-year-old girl with isolated LVNC. Next, we generated six lines of transgenic mice carrying a p.Met532Arg mutant alphaMHC gene, which was identical with the p.Met531Arg mutation in the human betaMHC. Among these, two lines with strong expression of the mutant alphaMHC gene were chosen for further studies. Although they did not exhibit the features characteristic of LVNC, approx. 50% and 70% of transgenic mice in each line displayed LVH (LV hypertrophy) by 2-3 months of age. Furthermore, LVD (LV dilation) developed in approx. 25% of transgenic mice by 18 months of age, demonstrating biphasic changes in LV wall thickness. The present study supports the idea that common mechanisms may be involved in LVH and LVD. The novel mouse model generated can provide important information for the understanding of the pathological processes and aetiology of cardiac dilation in humans.     

Baroreceptors mask sympathetic responses to high intraocular pressure in dogs

These experiments were designed to investigate whether increasing intraocular pressure (IOP) in anesthetized dogs produces differential control of sympathetic nerve activities to various organs (heart, kidney, liver, and spleen) and if these sympathetic responses are modified by baroreceptors. We performed simultaneous multi-recordings of cardiac, renal, hepatic and splenic sympathetic nerve activities (CNA, RNA, HNA and SpNA, respectively) during 2 min of increasing IOP to a mean pressure of 30 mmHg. After increasing IOP in dogs with the intact baroreceptors, all of measured nerve activities did not change significantly throughout the experiment. In dogs with denervation of baroreceptors (cervical vagotomy with denervation of the carotid sinus and aortic nerves), only RNA and CNA showed significant increases in response to the increased IOP. However, time course changes in HNA and SpNA did not show any significant differences as compared with the baseline or that of the control group. These results indicate that systemic sympathetic nerve responses to increasing IOP are masked by systemic baroreceptors. As animals were denervated of their systemic baroreceptors, the unidirectional sympathoexcitatory responses to increased IOP were observed on CNA and RNA, but not on HNA and SpNA. These sympathetic outflow, when systemic baroreceptors are impaired as observed in old age, may play an important role in management of glaucoma attack with the use of adrenolytic drugs.