Effect of l-thyroxine administration before breakfast vs at bedtime on hypothyroidism: A meta-analysis

PURPOSE

To compare the effects of l-thyroxine (L-T4) administration before breakfast and administration at bedtime on hypothyroidism.

METHODS

The PubMed, EMBASE, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI) and Wanfang databases were searched to identify relevant articles. All prospective or randomized controlled studies (RCTs) comparing L-T4 administration before breakfast to the administration at bedtime in patients with hypothyroidism were included in the analysis.

RESULTS

Initially, 2884 articles were retrieved from the databases, and 10 articles were included in the quantitative analysis. The effect of L-T4 administration before breakfast compared with administration at bedtime had no statistically significant association with hormone thyrotropin (TSH) (Standardized mean differences [SMD] = 0.09, 95% confidence intervals (CI): -0.12, 0.30; P = .39), or free triiodothyronine (FT3) (SMD=-0.19, 95% CI: -0.53, 0.15; P = .28) in patients with hypothyroidism. However, the result of FT4 level was favourable for L-T4 bedtime administration group (SMD=-0.27, 95% CI: -0.52, -0.02; P = .03).

CONCLUSION

Our meta-analysis revealed that L-T4 administration at bedtime is as effective as administration before breakfast for patients with hypothyroidism. Taking L-T4 at bedtime may be an attractive option for patients with hypothyroidism.

The Combined Effects of Magnesium Oxide and Inulin on Intestinal Microbiota and Cecal Short-Chain Fatty Acids

Constipation is a common condition that occurs in many people worldwide. While magnesium oxide (MgO) is often used as the first-line drug for chronic constipation in Japan, dietary fiber intake is also recommended. Dietary fiber is fermented by microbiota to produce short-chain fatty acids (SCFAs). SCFAs are involved in regulating systemic physiological functions and circadian rhythm. We examined the effect of combining MgO and the water-soluble dietary fiber, inulin, on cecal SCFA concentration and microbiota in mice. We also examined the MgO administration timing effect on cecal SCFAs. The cecal SCFA concentrations were measured by gas chromatography, and the microbiota was determined using next-generation sequencing. Inulin intake decreased cecal pH and increased cecal SCFA concentrations while combining MgO increased the cecal pH lowered by inulin and decreased the cecal SCFA concentrations elevated by inulin. When inulin and MgO were combined, significant changes in the microbiota composition were observed compared with inulin alone. The MgO effect on the cecal acetic acid concentration was less when administered at ZT12 than at ZT0. In conclusion, this study suggests that MgO affects cecal SCFA and microbiota during inulin feeding, and the effect on acetic acid concentration is time-dependent.

Timing Matters: Time of Day Impacts the Ergogenic Effects of Caffeine-A Narrative Review

Caffeine has attracted significant attention from researchers in the sports field due to its well-documented ergogenic effects across various athletic disciplines. As research on caffeine continues to progress, there has been a growing emphasis on evaluating caffeine dosage and administration methods. However, investigations into the optimal timing of caffeine intake remain limited. Therefore, this narrative review aimed to assess the ergogenic effects of caffeine administration at different times during the morning (06:00 to 10:00) and evening (16:00 to 21:00). The review findings suggest that circadian rhythms play a substantial role in influencing sports performance, potentially contributing to a decline in morning performance. Caffeine administration has demonstrated effectiveness in mitigating this phenomenon, resulting in ergogenic effects and performance enhancement, even comparable to nighttime levels. While the specific mechanisms by which caffeine regulates circadian rhythms and influences sports performance remain unclear, this review also explores the mechanisms underlying caffeine's ergogenic effects, including the adenosine receptor blockade, increased muscle calcium release, and modulation of catecholamines. Additionally, the narrative review underscores caffeine's indirect impact on circadian rhythms by enhancing responsiveness to light-induced phase shifts. Although the precise mechanisms through which caffeine improves morning performance declines via circadian rhythm regulation necessitate further investigations, it is noteworthy that the timing of caffeine administration significantly affects its ergogenic effects during exercise. This emphasizes the importance of considering caffeine intake timing in future research endeavors to optimize its ergogenic potential and elucidate its mechanisms.

Influence of administration timing of San-Huang-Xie-Xin-Tang treatment on attenuating Salmonella enterica serovar Typhimurium infection

Salmonella infections are a serious global health concern, particularly in developing countries, and are further exacerbated by the emergence of antibiotic resistance. San-Huang-Xie-Xin-Tang (SHXXT), a traditional herbal medicine with potent anti-inflammatory properties, has recently gained attention as an alternative treatment. Our study emphasizes on the importance of precise timing in accordance with traditional Chinese medicine principles. A mouse infection model was established while different administration times of SHXXT were recorded for the body weight, clinical scores, bacterial counts in blood, and organs. Additionally, cytokine levels, fatty acids, and amino acids in the serum were also monitored. We found that administering SHXXT 1 day after Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infection (T1 group) leads to positive outcomes. This includes restoration of body weight, improved clinical scores, and reduced bacterial counts in blood and vital organs. Interferon-gamma levels remained consistently high across all treatment groups 6 days post-infection. However, the T1 group showed exclusive suppression of serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β). The timing of administration significantly influenced serum fatty acid concentrations, countering Salmonella-induced disruptions, aligning with TNF-α and IL-1β levels. SHXXT had also restored amino acid profiles disrupted by the infection, with notable effects when administered at the correct timing. Our research highlights SHXXT's potential in treating S. Typhimurium infection, emphasizing the importance of precise timing in line with traditional Chinese medicine principles for effective treatment at different disease stages.

[The Analgesic Effect of Aspirin on Inflammatory Pain in Rats Is Affected by Pain Intensity and Administration Timing]

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely known as painkillers. The analgesic action of NSAIDs is attributable to the inhibition of prostaglandin synthesis that occurs in response to blocking cyclooxygenase activity. The effective dose of NSAIDs can vary depending on pain intensity and administration timing; however, there are few studies on this. This study aimed to elucidate whether the analgesic effect of NSAIDs changes depending on the situation in which they are taken and we focused on the NSAID, aspirin (ASP). In a rat model of brewer's yeast-induced inflammation, pain caused by 20% (w/v) brewer's yeast-treatment was defined as "strong pain" and that caused by 2.5% (w/v) was defined as "weak pain". The analgesic effect of ASP (low-dose; 44 mg/kg or high-dose; 66 mg/kg) against strong pain was dose-dependent, but that against weak pain was the same. Furthermore, we defined drug administration after 3 h of brewer's yeast-treatment as "late administration" and that after 20 min as "early administration". In the case of strong pain, the analgesic effect of "late ASP administration" was dose-dependent, but that of "early ASP administration" was the same. These results suggest that low-dose NSAIDs have an analgesic effect against weak pain or when taken early.