Plasma carotenoids and risk of acute myocardial infarction in the Singapore Chinese Health Study

Background and aim

Modification of low-density lipoprotein due to oxidative stress is essential in the development of coronary atherosclerosis. Data of specific carotenoids except β-carotene on cardioprotective effects in humans are limited.

Methods and results

This study examined the associations between plasma concentrations of specific carotenoids and incidence of acute myocardial infarction. The study included 280 incident cases of acute myocardial infarction and 560 matched controls nested within the Singapore Chinese Health Study, a prospective cohort of 63,257 Chinese men and women aged 45-74 years old enrolled in 1993-1998 in Singapore. Retinol and carotenoids in prediagnostic plasma were quantified using high-performance liquid chromatography. High levels of plasma β-cryptoxanthin and lutein were associated with decreased risk of acute myocardial infarction after adjustment for multiple risk factors for coronary heart disease. For β-cryptoxanthin, the odds ratio (95% confidence interval) for the highest (Q5) versus the lowest (Q1) quintile was 0.67 (0.37-1.21) (P for trend = 0.03). For lutein, the odds ratios (95% confidence intervals) for the combined Q2-Q3 and the combined Q4-Q5 versus Q1 were 0.71 (0.45-1.12) and 0.58 (0.35-0.94) respectively (P for trend = 0.03). There was no statistically significant association between other carotenoids or retinol and risk of acute myocardial infarction.

Conclusions

High plasma levels of β-cryptoxanthin and lutein were associated with decreased risk of acute myocardial infarction. The findings of this study support a cardioprotective role of these two carotenoids in humans.     

Long-term green tea catechin administration prevents spatial learning and memory impairment in senescence-accelerated mouse prone-8 mice by decreasing Aβ1-42 oligomers and upregulating synaptic plasticity–related proteins in the hippocampus

The senescence-accelerated mouse prone-8 (SAMP8) is characterized by early onset of learning and memory deficits along with spontaneous overproduction of soluble β-amyloid peptide (Aβ) in the brain. In our study, 4 month old male SAMP8 mice were orally administered 0.05% and 0.1% green tea catechins (GTC, w/v) in drinking water for 6 months. We found that a supplementation with 0.05% or 0.1% GTC prevented spatial learning and memory impairments of mice in the Morris water maze. Better performance of GTC-treated mice was associated with decreased levels of Aβ_1-42 oligomers in the hippocampus. The activity of the protein kinase A/cAMP-response element binding protein (PKA/CREB) pathway, one of the molecular targets of Aβ oligomers which is crucial for late long-term potentiation and long-term memory formation, was significantly increased after GTC administration. We also found that chronic 0.05% or 0.1% GTC consumption prevented the reductions of three representative proteins of synaptic function and synaptic structure, including brain-derived neurotrophic factor(BDNF), post-synaptic density protein-95 (PSD95) and Ca²⁺/calmodulin-dependent protein kinase II (CaMKII). These results demonstrated that long-term 0.05% or 0.1% green tea catechin administration may prevent spatial learning and memory decline of SAMP8 mice by decreasing Aβ_1-42 oligomers and upregulating synaptic plasticity–related proteins in the hippocampus.     

An effective dose of ketamine for eliminating pain during injection of propofol: A dose response study

Background and purpose

Ketamine can completely eliminate pain associated with propofol injection. However, the effective dose of ketamine to eliminate propofol injection pain has not been determined. The purpose of this study was to determine the effective dose of ketamine needed to eliminate pain in 50% and 95% of patients (ED50 and ED95, respectively) during propofol injections.

Methods

This study was conducted in a double-blinded fashion and included 50 patients scheduled for elective gynecological laparoscopy under general anesthesia. The initial dose of ketamine used in the first patient was 0.25 mg/kg. The dosing modifications were in increments or decrements of 0.025 mg/kg. Ketamine was administered 15 seconds before injecting propofol (2.5 mg/kg), which was injected at a rate of 1 mL/s. Patients were asked to rate their pain during propofol injection every 5 seconds using a 0–3 pain scale. The highest pain score was recorded. The ED50, ED95 and 95% confidence intervals (CI) were determined by probit analyses.

Results

The dose of ketamine ranged from 0.175 to 0.275 mg/kg. The ED50 and ED95 of ketamine for eliminating pain during propofol injection were 0.227 mg/kg and 0.283 mg/kg, respectively (95%CI: 0.211–0.243 mg/kg and 0.26–0.364 mg/kg, respectively).

Conclusion

Ketamine at an approximate dose of 0.3 mg/kg was effective in eliminating pain during propofol injection.     

A 90-day oral toxicity study on a new strain of Lactobacillus paracasei in rats

Lactobacillus paracasei is a species of bacteria that has been suggested to have probiotic benefits. To investigate the subchronic toxicity of L. paracasei GW080, a 90-feeding study was conducted in rats. Sprague-Dawley rats were randomly divided into four groups (10 rats/sex/group) and treated with 0, 1.25, 2.5, and 5.0 g/kg body weight (approximately equivalent to 0, 2.5 × 10⁹, 5.0 × 10⁹ and 1 × 10¹⁰ cfu/kg bw) of test material by gavage for 90 days. Daily clinical observations and weekly measurement of body weights and food consumption were conducted. Blood samples were obtained on day 46 and day 91 for the measurement of hematology and clinical chemistry parameters. Animals were euthanized for necropsy. Selected organs were weighted and recorded. Histological examination was performed on all tissues from animals in the control and high dose groups. No mortality, body weight, food consumption or treatment-related findings in clinical observations, macroscopic or microscopic examinations were observed. Differences between treated and control groups in some hematology and clinical chemistry parameters were not considered treatment-related. The no-observed-adverse-effect-level (NOAEL) for L. paracasei GM080 was considered to be 5.0 g/kg body weight (approximately equivalent to 1 × 10¹⁰ cfu/kg bw) for both genders, the highest dose tested.     

Prognosis evaluation in alpha-fetoprotein negative hepatocellular carcinoma after hepatectomy: Comparison of five staging systems

Aims

Alpha-fetoprotein (AFP) loses its potentials in treatment evaluation and prognosis prediction in patients with AFP negative (≤20 ng/ml) hepatocellular carcinoma (HCC). The present study was to identify the risk factors affecting postoperative survival of AFP negative patients and to determine the optimal staging system in predicting the survival of these patients.

Methods

The data of 306 in total and 98 AFP negative patients amongst were retrospectively reviewed. The risk factors affecting survivals of the patients were identified. And various staging systems were compared, including the sixth tumor node metastasis (TNM) system, Okuda staging, Cancer of the Liver Italian Program (CLIP) score, the Barcelona Clinic Liver Cancer (BCLC) staging system, and the Japan Integrated Staging (JIS) score.

Results

AFP negative patients tended to have intact tumor capsule and earlier staged tumor by TNM, CLIP and BCLC. The independent risk factors worsening overall survival of AFP negative patients were absence of tumor capsule, Child-Pugh classification B, hepatitis B surface antigen positive and BCLC stage B–C. The risk factors promoting tumor recurrence were tumor size of >3 cm, distribution in two lobes, Okuda stage B–C and BCLC stage B–C.

Conclusion

Normal AFP level implies earlier staged tumors. BCLC has the strongest potential in prognosis evaluation in AFP negative patients.     

Aging affects medial but not anterior frontal learning-related theta oscillations

Aging induces a decline in the ties that bind anatomical networks centered on the prefrontal cortex, which are critical for reinforcement learning and decision making. At the neurophysiological level, the prefrontal cortex may engage electrophysiological oscillatory synchronization to coordinate other brain systems during learning. We recorded scalp EEG from 21 older (mean age 69 years) and 20 young (mean age 22 years) healthy human adults while they learned stimulus–response mappings by trial-and-error using feedback. In young adults, theta-band (4–8 Hz) oscillatory power over medial frontal and anterior frontal cortex predicted learning after errors. Older adults demonstrated a decrease in the theta-band learning-predictive signals over medial frontal but not anterior frontal cortex. This age-related decrease in task-relevant medial frontal theta power may be related to the more general decrease in medial frontal theta power that we observed during rest. These results demonstrate a shift in cortical networks that support reinforcement learning in older adults, and shed new light on the changes in neurophysiological (oscillatory) mechanisms with neurocognitive aging.     

Effects of cementum–dentine junction and cementum on the mechanical response of tooth supporting structure

Objectives

The aim of the present work is to investigate the effects of cementum–dentine junction (CDJ) and cementum on the stress distribution in the periodontal ligament (PDL) and alveolar bone.

Methods

Based on the anatomical profiles and the recently reported theories about the tooth attachment mechanism, the finite element (FE) model of a mandibular second premolar along with its detailed supporting structures was developed. The effect of CDJ and cementum was evaluated by comparing the resulting stresses of FE models of the second mandibular premolar with and without CDJ and cementum in tooth supporting structure.

Results

The stress levels are higher in the structure without CDJ and cementum than that with CDJ and cementum. The function of CDJ and cementum is as a cushion pad decreasing the stress in the PDL and alveolar bone under loading.

Conclusions

As a major result of this study, it can be concluded that the CDJ and cementum significantly influence the stress distribution within the tooth supporting structure. However, most of the reported FE analysis did not take CDJ and cementum into account, which possibly resulted in overestimated stress values in the PDL and alveolar bone. From a bio-engineering perspective, the results of this study provide guidance for the design of dental implants and the application of orthodontic force system as well.