Effect of transplantation of the foetal testis to neonatal female rats on differentiation of the postpubertal secretory pattern of gonadotrophin.

Rat foetal testes (day 19 or 20 pregnancy) were transplanted into the neck of 3-day-old female rats. When testicular grafts were left in the recipients until autopsy (at 90 days of age), anovulatory persistent oestrous syndrome developed in most of the recipient females. These changes were not influenced by the removal at 45 days of age of the testicular grafts. However, the incidence of anovulatory sterility was significantly reduced when the foetal testicular grafts had been removed 5 days after transplantation. Treatment of these recipient females with 40 IU HCG from the day of the transplantation to the day before the removal of the transplants markedly increased the incidence of anovulatory sterility in the recipient females. In histological examinations of the testicular grafts upon their removal, a significant stimulation of Leydig cell elements was noted in the groups of rats treated with HCG. It is highly probable that if sufficient levels of gonadotrophin (GTH) are present in the recipient females, testicular tissues from day 18-20 foetuses can secrete sufficient amounts of androgen for masculinizing GTH regulation.     

Up‐regulation of Rac1 in the bronchial smooth muscle of murine experimental asthma

There has been considerable research on the involvement of RhoA/Rho kinase signalling in smooth muscle contractions. However, only a few reports have addressed the specific role of Rac1, which is a member of the Rho GTPase superfamily. Therefore, this study investigated the role of Rac1‐related pathways in bronchial smooth muscle (BSM) contractions. Bronchial rings isolated from mice were suspended in an organ bath, and the isometric contractions of circular smooth muscles were monitored. The phosphorylation of myosin light chains (MLCs) was analysed by immunoblotting. The Rac1 inhibitor EHT1864 inhibited carbachol (CCh)‐induced BSM contractions, although high K⁺ depolarization‐induced BSM contractions were not significantly attenuated by EHT1864. Moreover, high K⁺‐ and phorbol 12,13‐dibutyrate (PDBu; PKC activator)‐induced contractions were not attenuated by Rac1 inhibition, whereas sodium fluoride (NaF)‐induced force development was inhibited by EHT1864. The gene and protein expression of Rac1 was increased in the BSM of a murine model with antigen‐induced airway hyper‐responsiveness (AHR). In addition, an increased force of the BSM contractions in AHR was suppressed by EHT1864 treatment, suggesting that the up‐regulation of Rac1 is involved in AHR. These findings suggest that an increase in Rac1‐mediated signalling is involved in the augmented contractions of BSMs in antigen‐induced AHR mice.     

Interferential Electric Stimulation Applied to the Neck Increases Swallowing Frequency

Swallowing disorders are a common complaint among the elderly. Recently, surface electrical stimulation applied to the neck region has received increased attention as a new modality to treat pharyngeal dysphagia. Previous reports used pulsed current at a frequency range of 1-120 Hz. Kilohertz-frequency alternating currents (ACs) have not been tested for treating dysphagia. Therefore, we evaluated the effects of interferential currents (IFCs), the most popular modality of amplitude-modulated kilohertz-frequency ACs in clinical practice, on the swallowing reflex in healthy subjects. We found that IFC stimulation at the sensory threshold with 50-Hz modulation significantly increased the number of swallows without any discomfort, but pure AC stimulation at the carrier frequency did not have a significant effect. There was no statistically significant difference in the time course of the number of swallows among 1,000-, 2,000-, 4,000-, and 6,000-Hz carrier frequencies. The number of swallows remained increased during the 15-min IFC stimulation, suggesting that IFC stimulation facilitates the swallowing reflex without adaptation, at least during this stimulation period. We suggest that an IFC stimulation or a low-frequency, modulated kilohertz AC stimulation, which would be more comfortable than pulsed currents, is an alternative stimulation mode for treating pharyngeal dysphagia.     

Effects of bile-acid-binding resin (colestimide) on blood glucose and visceral fat in Japanese patients with type 2 diabetes mellitus and hypercholesterolemia: an open-label, randomized, case-control, crossover study

ObjectiveThe objective was to examine the effects of colestimide on blood glucose, visceral fat, adipocytokines, and bile acid conjugate fractions in Japanese patients.MethodsThis study was an open-label, randomized, case–control, crossover study of colestimide 3 g/day in 40 Japanese patients with type 2 diabetes mellitus (T2D) and hypercholesterolemia. Patients were assigned to the colestimide group in which pravastatin and colestimide were administered orally and to the statin group in which pravastatin alone was administered orally. The principal outcome measures were serum lipid levels, fasting plasma glucose level in the early morning, hemoglobin A1c (HbA_1c), visceral fat area (VFA), and serum 1,5-anhydroglucitol (1,5-AG) level.ResultsSerum low-density lipoprotein cholesterol levels significantly decreased from 113±38 mg/dl at baseline to 90±20 mg/dl (P=.009) at week 12 of colestimide administration. HbA_1c significantly decreased from 7.4%±0.9% at baseline to 6.9%±0.9% (P=.001) at week 12 of colestimide administration. Serum 1,5-AG levels increased from 9.4±10.1 μg/ml to 12.4±9.5 μg/ml (P=.05) at week 12 of colestimide administration. The statin group showed no significant changes in lipids and 1,5-AG. However, ΔVFA was inversely correlated with Δcholic acid, and multivariate analysis revealed that ΔVFA was a significant explanatory variable.ConclusionsColestimide holds promise not only for the treatment of hypercholesterolemia but also for the possible improvement of T2D and visceral fat obesity.     

Computational study on the polymerization reaction of d-aminopeptidase for the synthesis of d-peptides

Almost all natural proteins are composed exclusively of l-amino acids, and this chirality influences their properties, functions, and selectivity. Proteases can recognize proteins composed of l-amino acids but display lower selectivity for their stereoisomers, d-amino acids. Taking this as an advantage, d-amino acids can be used to develop polypeptides or biobased materials with higher biostability. Chemoenzymatic peptide synthesis is a technique that uses proteases as biocatalysts to synthesize polypeptides, and d-stereospecific proteases can be used to synthesize polypeptides incorporating d-amino acids. However, engineered proteases with modified catalytic activities are required to allow the incorporation of d-amino acids with increased efficiency. To understand the stereospecificity presented by proteases and their involvement in polymerization reactions, we studied d-aminopeptidase. This enzyme displays the ability to efficiently synthesize poly d-alanine-based peptides under mild conditions. To elucidate the mechanisms involved in the unique specificity of d-aminopeptidase, we performed quantum mechanics/molecular mechanics simulations of its polymerization reaction and determined the energy barriers presented by the chiral substrates. The enzyme faces higher activation barriers for the acylation and aminolysis reactions with the l-stereoisomer than with the d-substrate (10.7 and 17.7 kcal mol⁻¹ higher, respectively). The simulation results suggest that changes in the interaction of the substrate with Asn155 influence the stereospecificity of the polymerization reaction.

We studied the molecular mechanism of d-aminopeptidase for the synthesis of polypeptides incorporating d-amino acids.     

Ultrasound-guided infraclavicular axillary vein puncture is effective to avoid pinch-off syndrome: a long-term follow-up study

Purpose

Pinch-off syndrome (POS) is a serious complication encountered during the long-term management of totally implantable access ports (TIAPs). The aim of this study was to examine the effect of ultrasound-guided infraclavicular axillary vein puncture to avoid POS in patients with long-term use of a TIAP.

Methods

This was a retrospective review of 207 consecutive TIAPs: one hundred devices implanted using an anatomical landmark technique were used as historical controls (Landmark group), while 107 devices were implanted using an ultrasound (US)-guided puncture method (US group). The pinch-off grade (POG) was determined using chest X-ray findings following the definition of Hinke, and the progression of POG during the follow-up period of the Landmark and US groups was compared.

Results

Sixteen cases in the Landmark group were POG-1 and 3 were POG-2, while all cases in the US group were POG-0 at the time of venipuncture (p < 0.001). Eleven patients in the Landmark group showed some degree of progression of the POG during the follow-up period. In contrast, there were no cases showing progression of the POG in the US group (p = 0.002).

Conclusions

US-guided infraclavicular axillary vein puncture was found to effectively make it possible to avoid POS for the long-term management of TIAPs, as well as at the time of implantation.     

Effect of the Volume of Fluid Ingested on Urine Concentrating Ability During Prolonged Heavy Exercise in a Hot Environment

This study examined the effect of the volume of fluid ingested on urine concentrating ability during prolonged heavy exercise in a hot environment at low levels of dehydration. Seven healthy males performed 105 min of intermittent cycle exercise at 70% maximum oxygen uptake (32°C, 60% relative humidity) while receiving no fluid ingestion (NF), voluntary fluid ingestion (VF), partial fluid ingestion equivalent to one-half of body mass loss (PF), and full fluid ingestion equivalent to body mass loss (FF). Fluid (5°C, 3.4% carbohydrate, 10.5 mmol·L^-1 sodium) was ingested just before commencing exercise and at 15, 33, 51, 69, and 87 min of exercise, and the total amount of fluid ingested in PF and FF was divided into six equal volumes. During exercise, body mass loss was 2.2 ± 0.2, 1.1 ± 0.5, 1.1 ± 0.2, and 0.1 ± 0.2% in NF, VF, PF, and FF, respectively, whereas total sweat loss was about 2% of body mass in each trial. Subjects in VF ingested 719 ± 240 ml of fluid during exercise; the volume of fluid ingested was 1.1 ± 0.4% of body mass. Creatinine clearance was significantly higher and free water clearance was significantly lower in FF than in NF during exercise. Urine flow rate during exercise decreased significantly in NF. There were significant decreases in creatinine and osmolar clearance and was a significant increase in free water clearance during exercise in NF and VF. Creatinine clearance decreased significantly and free water clearance increased significantly during exercise in PF. There was no statistical change in urinary indices of renal function during exercise in FF. The findings suggest that full fluid ingestion equivalent to body mass loss has attenuated the decline in urine concentrating ability during prolonged heavy exercise in a hot environment at low levels of dehydration.

Key points

• During prolonged heavy exercise in a hot environment at low levels of dehydration, fluid ingestion equivalent to body mass loss results in no changes in urinary indices of renal function.
• Fluid ingestion equivalent to body mass loss can attenuate the decline in urine concentrating ability during exercise.
• Ad libitum or voluntary fluid ingestion is ineffective in reducing the decline in urine concentrating ability during exercise.

Key words: Body fluid, dehydration, heat stress, rehydration, renal function     

Comparative analysis of LTR and structural genes in an equine infectious anemia virus strain isolated from a feral horse in Japan

Although equine infectious anemia virus (EIAV) poses a major threat to the equine industry worldwide, the molecular epidemiology of this virus is poorly understood. Recently, an EIAV strain (EIAV_{Miyazaki2011-A}) representing a new monophyletic group was discovered in feral horses in southern Japan. In the present study, the EIAV_{Miyazaki2011-A} proviral genome is compared with evolutionarily divergent EIAV isolates to investigate conservation of functional elements or motifs within the long terminal repeats (LTRs) and structural genes. This analysis represents a significant step forward in increasing understanding of the molecular conservation and variation between geographically distinct strains of this equine lentivirus.