Distribution of the longevity gene product, SIRT1, in developing mouse organs

A longevity gene product, Sir2 (silent information regulator 2) is a NAD-dependent histone deacetylase involved in longevity in yeasts, worms and flies. The mammalian homolog of Sir2, SIRT1(sirtuin 1), has been shown to play important roles related to anti-aging effects (regulating apoptosis, stress tolerance, insulin resistance, and fat metabolism). Recently, SIRT1 expression has been demonstrated to occur at as early as embryonic day 10.5 in mice. SIRT1 during developing period may be involved in the mechanism of developmental origins of adult diseases, such as diabetes and cardiovascular disease. To investigate the contribution of SIRT1, it is important to reveal the distribution of this protein during development. In the present study, we demonstrated the distribution of immunoreactivity of SIRT1 in mouse organs during prenatal and neonatal development by staining a wide variety of serial sections. The SIRT1 immunoreactivity was strongly observed in the neuroepithelial layer, dorsal root ganglion, trigeminal ganglion, eyes, roots of whiskers, and internal organs, including the testis, liver, heart, kidney, and lung during the fetal period. Neurons which had finished migrating still showed relatively strong immunoreactivity. The immunoreactivity was completely absorbed by the blocking peptide in an absorption test. During the postnatal period, the immunoreactivities in most of these organs, except the heart and testis weakened, with the liver most dramatically affected. As SIRT1 expression was demonstrated in a wide variety of developing organs, further study to investigate prenatal factors which affect SIRT1 expression and its activity is important.     

Effects of a low-fat meal on the oral bioavailability of UFT and leucovorin in patients with colorectal cancer

Background

UFT is composed of tegafur, a prodrug of 5-fluorouracil, and uracil, at a fixed ratio of 1: 4. UFT is widely used with leucovorin as adjuvant chemotherapy in patients with colon cancer. As reported, UFT/leucovorin should not be taken simultaneously with food because a high fat content will reduce the systemic exposure to the active cytotoxic moiety of UFT. In this single-dose, randomized, two-way crossover study, we investigated the effects of a low-fat Japanese meal on the pharmacokinetics and oral bioavailability of UFT (2 × 100-mg capsules; dose in terms of tegafur) and leucovorin (1 × 25-mg tablet).

Methods

Patients (n = 12) were randomly assigned to receive both drugs after an overnight fast or 5 min after eating a standard Japanese breakfast (641 kcal), with a 3-day washout period between treatments. Pharmacokinetics (n = 12) were determined for tegafur, 5-fluorouracil, uracil, leucovorin, and 5-methyltetrahydrofolate (an active metabolite of leucovorin).

Results

For 5-fluorouracil pharmacokinetics, the maximum plasma concentration and the area under the curve were reduced by 73.7% and 47.4%, respectively, when UFT was taken postprandially, and the maximum plasma concentration and the area under the curve for uracil were reduced by 84.1% and 68.9%, respectively, compared with dosing on an empty stomach. These decreases in the systemic exposure to 5-fluorouracil were quite marked and may have an impact on its antitumor effect.

Conclusion

A low-fat meal affects the pharmacokinetics of UFT similarly to a high-fat meal.     

Immunohistochemical assessment of proliferative activity in mammary adenomyoepithelioma

Aims : Two cases of adenomyoepithelioma of the breast were examined by immunohistochemistry to evaluate proliferative activity of epithelial and myoepithelial components. Methods and results : The tumours showed a bicellular pattern of gland-forming epithelial cells and proliferative myoepithelial cells with clear cytoplasm. They showed foci of monotonous growth of myoepithelial cells devoid of glands with low mitotic rate (1 ∼ 2/10 high-power fields) and mild cytological atypia. Immunohistochemically, the glandular cells were positive for epithelial membrane antigen, cytokeratin (KL-1 and CAM5.2) and carcinoembryonic antigen, whereas tumour cells with clear cytoplasm were reactive with muscle-specific actin (MSA), alpha smooth muscle actin, vimentin, and S100 protein but negative for desmin. Proliferative activities assessed by MIB-1(Ki-67)/MSA positive cell index were greater in myoepithelial cells in both cases (19.2% and 17.7%) as compared to those in epithelial cells (MIB-1/CAM5.2 index: 10.2% and 9.5%). Conclusions : These results might account for the previous findings that myoepithelial components predominate over the epithelial ones in an advanced stage of this tumour as well as in recurrent or metastatic lesions.     

Maintenance for healed erosive esophagitis: Phase Ⅲ comparison of vonoprazan with lansoprazole

AIM To compare vonoprazan 10 and 20 mg vs lansoprazole 15 mg as maintenance therapy in healed erosive esophagitis(EE).METHODS A total of 607 patients aged ≥ 20 years, with endoscopically-confirmed healed EE following 8 wk of treatment with vonoprazan 20 mg once daily, were randomized 1:1:1 to receive lansoprazole 15 mg(n = 201), vonoprazan 10 mg(n = 202), or vonoprazan 20 mg(n = 204), once daily. The primary endpoint of the study was the rate of endoscopically-confirmed EE recurrence during a 24-wk maintenance period. The secondary endpoint was the EE recurrence rate at Week 12 during maintenance treatment. Additional efficacy endpoints included the incidence of heartburn and acid reflux, and the EE healing rate 4 wk after the initiation of maintenance treatment. Safety endpoints comprised adverse events(AEs), vital signs, electrocardiogram findings, clinical laboratory results, serum gastrin and pepsinogen Ⅰ/Ⅱ levels, and gastric mucosa histopathology results.RESULTS Rates of EE recurrence during the 24-wk maintenance period were 16.8%, 5.1%, and 2.0% with lansoprazole 15 mg, vonoprazan 10 mg, and vonoprazan 20 mg, respectively. Vonoprazan was shown to be non-inferior to lansoprazole 15 mg(P 0.0001 for both doses). In a post-hoc analysis, EE recurrence at Week 24 was significantly reduced with vonoprazan at both the 10 mg and the 20 mg dose vs lansoprazole 15 mg(5.1% vs 16.8%, P = 0.0002, and 2.0% vs 16.8%, P 0.0001, respectively); by contrast, the EE recurrence rate did not differ significantly between the two doses of vonoprazan(P = 0.1090). The safety profiles of vonoprazan 10 and 20 mg were similar to that of lansoprazole 15 mg in patients with healed EE. Treatment-related AEs were reported in 11.4%, 10.4%, and 10.3% of patients in the lansoprazole 15 mg, vonoprazan 10 mg, and vonoprazan 20 mg arms, respectively.CONCLUSION Our findings confirm the non-inferiority of vonoprazan 10 and 20 mg to lansoprazole 15 mg as maintenance therapy for patients with healed EE.     

Routine use of the intubating laryngeal mask airway results in increased upper airway morbidity

PURPOSE: The classic laryngeal mask airway (LMA) has a soft, silicone tube and the intubating laryngeal mask airway (ILM) has a rigid, silicone-coated steel tube. We compare postoperative pharyngolaryngeal morbidity in patients randomised to receive either device. METHODS: Sixty-five female patients (ASA physical status class I or II, aged 18-80 yr) undergoing balanced regional anesthesia for gynecological laparotomy expected to last one to two hours were randomly assigned for airway management with the LMA or ILM. Intracuff pressure was maintained at 60 cm H20. Postoperative pharyngolaryngeal morbidity (sore throat, difficulty swallowing, sore mouth, sore neck/jaw, hoarseness) was assessed at two, 24 and 48 hr by blinded investigators. RESULTS: The number of insertion attempts and duration of anesthesia was similar between groups. Sore throat was more common for the ILM at two hours (44 vs 15%, P=0.01), 24 hr (59 vs 21%, P=0.008) and 48 hr (34 vs 3%, P=0.005). Sore mouth was more common for the ILM at two hours (16 vs 0%, P=0.02) and 24 hr (12 vs 0%, P=0.04), but not at 48 hr (6 vs 3%). Difficulty swallowing was more common for the ILM at two hours (25 vs 0%, P=0.04), but not at 24 hr (31 vs 3%) and 48 hr (12 vs 9%). There were no differences in the incidence of sore jaw/neck (ILM, 3-12%; LMA, 0-3%) and hoarseness (ILM, 12-31%; LMA, 16-18%). There was no correlation between postoperative pharyngolaryngeal morbidity and duration of anesthesia. CONCLUSION: Pharyngolaryngeal morbidity is more common with the ILM than the LMA following anesthesia lasting one to two hours.     

Syntaxin 1A occludes GABA(B) receptor-induced inhibition of exocytosis downstream of Ca(2+) entry in mouse hippocampal neurons

The mechanisms underlying gamma-amino butyric acid (GABA(B)) receptor-mediated inhibition of exocytosis have been characterized in a variety of synapses. Using patch-clamp recording methods, we attempted to clarify the intracellular mechanisms underlying presynaptic inhibition in autaptic synapses of isolated mouse hippocampal neurons. Baclofen, a selective GABA(B) receptor agonist, decreased the frequency of glutamatergic miniature excitatory postsynaptic currents (mEPSCs) without changing their amplitude in Ca(2+)-free extracellular solution, suggesting that baclofen inhibits exocytosis downstream of Ca(2+) entry. Syntaxin 1A is known to modulate exocytosis and suppress neuronal sprouting. Antisense oligonucleotide-mediated knockdown of syntaxin 1A increased the frequency of mEPSCs under Ca(2+)-free condition. Estimation of the number of functional release sites by staining with FM1-43 indicated that the increased frequency of mEPSCs was induced by facilitation of exocytosis at each site, rather than by an increased number of release sites due to neuronal sprouting. Baclofen reduced mEPSC frequency in syntaxin 1A-knockdown neurons to the same level as that in nonsense oligonucleotide transfected neurons under Ca(2+)-free condition. These results suggest that the GABA(B) receptor- and syntaxin 1A-induced inhibitions of exocytosis occlude one another and that the GABA(B) receptor shares a common intracellular pathway with syntaxin 1A in inhibiting transmitter release downstream of Ca(2+) entry.