24 EFFECT OF CULTURE OF SEMEN IN A LOW PRESSURE CONDITION AT ROOM TEMPERATURE ON VIABILITY AND CAPACITATION STATUS OF BOAR SPERM

Sperm are affected by physical conditions, such as centrifugation and temperature. The objective of this study was to examine the effect of a low atmospheric pressure on viability and capacitation status of boar sperm during semen preservation at room temperature. Sperm-rich fraction from Berkshire boars was diluted at cells mL–1 with modified Modena containing 20% seminal fluid after washing with centrifugation (300 × g for 35 min at room temperature) in a Percoll gradient (45%/90%). The sperm suspension was stored at a pressure of 0.5 or 1.0 atmospheres in the dark at room temperature (25°C). Following storage for 4 h or 4 days, the semen samples were analysed for viability, intracellular calcium level, and acrosome status of the sperm. Viability and intracellular calcium level of sperm were assessed by flow cytometry following staining with SYBR-Green/PI and Furo-3/PL, respectively. Sperm status associated with capacitation and acrosome reaction was analysed by CTC-assay under fluorescence microscope. Statistical analyses of data from 4 or 5 replicated trials were carried out by ANOVA and with a Bonferroni-Dunn post hoc test (significance, P < 0.05). Viability of sperm was not different (P = 0.50) between 2 pressures (0.5 and 1.0 atm) 4 h and 4 days after the start of storage (94.6% v. 95.6% and 92.7% v. 94.3%, respectively). Although the percentage of live sperm with high intracellular calcium levels drastically increased (P < 0.01) 4 days after the start of storage (20.2% v. 23.4%) compared with 4 h of storage (5.5% v. 4.9%), there were no differences between sperm stored in 0.5 and 1.0 atm at 4 h (P = 0.80) and 4 days of storage (P = 0.40). After 4 h of storage, there were no differences in the percentage of intact (93.3% v. 94.7%), capacitated (5.5% v. 4.3%), and acrosome-reacted sperm (1.5% v. 1.5%) between sperm stored in 0.5 and 1.0 atm. After 4 days of storage, however, the percentage of intact sperm decreased when the sperm suspension was cultured in 0.5 atm (71.8%) compared with 1.0 atm (88.5%), and the incidence of capacitated sperm increased (14.3% v. 7.8%, respectively), whereas there was no difference in the acrosome-reacted cells. These results demonstrate that the status of sperm associated capacitation is stimulated in a low atmospheric pressure without any effects of the viability of sperm, during storage for 4 days.

Doping-dependent nodal fermi velocity of the high-temperature superconductor Bi2Sr2CaCu2O(8+δ) revealed using high-resolution angle-resolved photoemission spectroscopy

The improved resolution of laser-based angle-resolved photoemission spectroscopy (ARPES) allows reliable access to fine structures in the spectrum. We present a systematic, doping-dependent study of a recently discovered low-energy kink in the nodal dispersion of Bi2Sr2CaCu2O(8+δ) (Bi-2212), which demonstrates the ubiquity and robustness of this kink in underdoped Bi-2212. The renormalization of the nodal velocity due to this kink becomes stronger with underdoping, revealing that the nodal Fermi velocity is nonuniversal, in contrast with assumed phenomenology. This is used together with laser ARPES measurements of the gap velocity (v2) to resolve discrepancies with thermal conductivity measurements.

Neurodegenerative influence of oxidative stress in the retina of a murine model of diabetes

AIMS/HYPOTHESIS

Diabetic retinopathy is a progressive neurodegenerative disease, but the underlying mechanism is still obscure. Here, we focused on oxidative stress in the retina, and analysed its influence on retinal neurodegeneration, using an antioxidant, lutein.

METHODS

C57BL/6 mice with streptozotocin-induced diabetes were constantly fed either a lutein-supplemented diet or a control diet from the onset of diabetes, and their metabolic data were recorded. In 1-month-diabetic mice, reactive oxygen species (ROS) in the retina were measured using dihydroethidium and visual function was evaluated by electroretinograms. Levels of activated extracellular signal-regulated kinase (ERK), synaptophysin and brain-derived neurotrophic factor (BDNF) were also measured by immunoblotting in the retina of 1-month-diabetic mice. In the retinal sections of 4-month-diabetic mice, histological changes, cleaved caspase-3 and TUNEL staining were analysed.

RESULTS

Lutein did not affect the metabolic status of the diabetic mice, but it prevented ROS generation in the retina and the visual impairment induced by diabetes. ERK activation, the subsequent synaptophysin reduction, and the BDNF depletion in the diabetic retina were all prevented by lutein. Later, in 4-month-diabetic mice, a decrease in the thickness of the inner plexiform and nuclear layers, and ganglion cell number, together with increase in cleaved caspase-3- and TUNEL-positive cells, were avoided in the retina of lutein-fed mice.

CONCLUSIONS/INTERPRETATION

The results indicated that local oxidative stress that has a neurodegenerative influence in the diabetic retina is prevented by constant intake of a lutein-supplemented diet. The antioxidant, lutein may be a potential therapeutic approach to protect visual function in diabetes.

Usefulness of the adenosine triphosphate with a sufficient observation period for detecting reconduction after pulmonary vein isolation

BACKGROUND

Although reconduction after pulmonary vein (PV) isolation is considered to play a key role in the recurrence of paroxysmal atrial fibrillation (AF), there have been few reports regarding the precise time course of early reconduction. Several studies have suggested that transient PV reconduction facilitated by adenosine may predict long-term AF recurrence. This study was designed to clarify the incidence and time course of early reconduction after PVI during the procedure and to confirm whether the use of ATP after a certain observation period was useful to detect early reconduction after PVI.

METHODS

In 21 patients (18 males, 56 +/- 11 years) with drug refractory AF, radiofrequency circumferential PV antrum ablation was performed in all 4 PVs. After the completion of isolation, electrograms in each PV were repeatedly recorded (1.98 +/- 0.57 times per PV) using a circular mapping catheter for an observation period of 87 +/- 29 minutes. After isolation of all 4 PVs, 30 mg of adenosine triphosphate (ATP) was administered during isoproterenol infusion.

RESULTS

PV electrical isolation was initially achieved in all 81 PVs. During the observation period, 12 (15%) PVs in 10 (48%) of 21 patients exhibited spontaneous reconduction. Among the remaining 69 PVs, 8 (12%) additional PVs had reconduction with the use of ATP. All PV reconduction was successfully eliminated by 4.5 +/- 2.2 additional radiofrequency applications.

CONCLUSION

A sufficient observation period and the use of ATP are useful to detect early reconduction after PV isolation.

Spin-related current suppression in a semiconductor quantum dot spin-diode structure

We experimentally study the transport features of electrons in a spin-diode structure consisting of a single semiconductor quantum dot (QD) weakly coupled to one nonmagnetic and one ferromagnetic (FM) lead, in which the QD has an artificial atomic nature. A Coulomb stability diamond shows asymmetric features with respect to the polarity of the bias voltage. For the regime of two-electron tunneling, we find anomalous suppression of the current for both forward and reverse bias. We discuss possible mechanisms of the anomalous current suppression in terms of spin blockade via the QD-FM interface at the ground state of a two-electron QD.

Relationship between hyperglycemia and coronary vascular resistance in non-diabetic patients

BACKGROUND

Hyperglycemia upon hospital admission in patients with acute myocardial infarction is associated with the no-reflow phenomenon after successful reperfusion, and increased mortality. However, the mechanism underlying this phenomenon remains unclear. Therefore, the aim of this study was to characterize coronary hemodynamics in a homogenous group of non-diabetic patients without coronary artery disease.

METHODS AND RESULTS

A total of 104 consecutive non-diabetic patients (mean age, 62+/-14 years) without coronary artery disease underwent Doppler flow study of the left anterior descending coronary artery. Vascular reactivity was examined by intra-coronary administration of papaverine, acetylcholine (Ach), and nitroglycerin using a Doppler guidewire. Coronary vascular resistance (CVR) was calculated as the mean arterial pressure divided by coronary blood flow (CBF). Baseline CVR was shown as CVR at control and minimal CVR was shown as CVR with papaverine administration. Fasting plasma glucose (FPG) level had a significant, positive correlation with baseline CVR and minimal CVR (r=0.24, p<0.02 and r=0.21, p<0.05, respectively). Hemoglobin A1c (HbA1c) also had a significant, positive correlation with baseline CVR and minimal CVR (r=0.31, p<0.01 and r=0.32, p<0.01, respectively). The percent change in CBF induced by Ach was inversely correlated with HbA1c but not with FPG (r=0.22, p<0.05 and r=0.06, p=0.57, respectively). By contrast, neither FPG nor HbA1c had significant correlation with coronary flow reserve to papaverine.

CONCLUSION

These data demonstrate that elevated glucose levels are associated with increases in baseline and minimal coronary vascular resistance. These changes may contribute to unfavorable coronary hemodynamics in non-diabetic patients without coronary heart disease.

Toll-like receptor 2 expression level on monocytes in patients with viral infections: monitoring infection severity

For viral infectious diseases, reliable biomarkers capable of monitoring recovery and therapeutic effects and that simultaneously discriminate between viral and bacterial infection are necessary. In this study, by using flow-cytometric quantification system, Toll-like receptor 2 (TLR2) expression levels on monocytes of influenza patients (n=47) were compared with those of healthy volunteers (n=50). Subsequently, throughout their acute, convalescent and healed phases, TLR2, C-reactive protein (CRP), serum amyroid A (SAA), and neopterin levels were followed. Additionally, TLR2 levels in other viral infectious diseases were assayed. The results showed that TLR2 level in influenza patients was remarkably up-regulated in acute phase compared to healthy volunteers (p<0.001). Thereafter, TLR2 levels normalized in good accordance with their recovery processes. CRP and neopterin levels were relatively widely distributed from normal to abnormally high levels in acute phase in spite of similar disease severity among the patients. SAA levels did not necessarily reflect the patients' clinical course during their recovery. Clinical observations of other viral infections also indicated that TLR2 levels were compatible with infection severity. TLR2 expression level on monocytes might serve as a unique biomarker useful in viral infectious diseases.

A technique for diagnosis of accessory pathway using the H-H and A-A intervals of the first entrained cycle during ventricular overdrive pacing

Although advancement of succeeding atrial activation by a ventricular extrastimulus (VES) on His refractoriness during supraventricular tachycardia (SVT) has been used as evidence of an accessory pathway (AP), the sensitivity of this method is suboptimal. This study was designed to compare the His-His (H-H) and atrial-atrial (A-A) intervals of the first entrained cycle during ventricular overdrive pacing (VOD) for the diagnosis of AP, in comparison to the conventional VES method. In 55 patients with SVT, a VES was elicited on His refractoriness during SVT. VOD was subsequently performed at cycle lengths 30 to 40 ms shorter than SVT cycle lengths. When the A-A interval became equal to the pacing cycle length after some beats of VOD, the cycle was considered the first entrained cycle and the H-H interval preceding the A-A interval was measured. VES advanced the next atrial activation in 16 patients (52%) with an AP, but in no patient without an AP. The H-H interval of the first entrained cycle was longer than the pacing cycle length by > or =15 ms in all patients with an AP, but was equal to the pacing cycle length in all patients without an AP. The criterion of H-H greater than A-A by > or =15 ms for the first entrained cycle provided higher diagnostic yield for AP compared with the VES method(100% vs 52%, p <0.001). In conclusion, this new criterion reliably diagnoses the presence of an AP in patients with SVT, with higher sensitivity compared with the VES method.

Time-course of Toll-like receptor 2 expression, as a predictor of recurrence in patients with bacterial infectious diseases

The clinical course of bacterial infectious diseases is often variable, especially in elderly patients. Thus, new biological markers have been sought to predict the disease outcome. Recent studies have revealed that Toll-like receptor (TLR) 2 and/or TLR4 on circulating monocytes are significantly up-regulated in bacterial infections. However, the lack of reliable quantification methods hampers extensive study on the modulation of these molecules in response to the patient's clinical condition. In this study, we developed a new quantitative flow cytometric analysis system for TLR2. We then carried out a longitudinal study on TLR2 expression levels on monocytes from patients suffering from bacterial infectious diseases during and after antibiotic treatment. The clinical outcome divided 37 patients into 'cure' (n = 24) and 'recurrence' (n = 13) groups. A significant difference between the two groups was recognized in the TLR2 levels just after antibiotic treatment (antibody-binding sites/cell, 4395 +/- 784 versus 5794 +/- 1484, P < 0.001). The risk of recurrence was associated significantly with TLR2 (P < 0.001), but not C-reactive protein (P = 0.351) levels assayed during the first remission. Furthermore, antibiotic effectiveness was associated inversely with TLR2 levels during antibiotic administration (P < 0.001). Taken together, TLR2 expression levels on monocytes provide critical information for planning treatment against bacterial infectious diseases.

Adiponectin is a better predictor of endothelial function of the coronary artery than HOMA-R, body mass index, immunoreactive insulin, or triglycerides

BACKGROUND

Previous studies have demonstrated that decreased levels of circulating adiponectin correlate with endothelial dysfunction in peripheral arteries. However, the relationship between adiponectin levels and endothelial function in coronary arteries remains unclear. The goal of the present study was to determine whether circulating adiponectin concentrations are a useful predictor of coronary endothelial function.

METHODS

Thirty-six consecutive non-diabetic patients with normal or mildly diseased coronary arteries were enrolled in this study. Coronary endothelial function was evaluated by coronary vascular response to acetylcholine (Ach). The relationship between coronary vasoreactivity and adiponectin or other biochemical or anthropometric parameters was investigated. The predictive value of adiponectin level for assessment of coronary endothelial dysfunction was assessed at the best cut-off point.

RESULTS

In a simple regression analysis, log-transformed adiponectin concentrations positively correlated with the percent change in coronary blood flow (CBF) and coronary artery diameter (CAD) induced by Ach (r=0.62, p<0.0001; r=0.63, p<0.0001, respectively). Insulin resistance index (HOMA-R), body mass index, immunoreactive insulin, and triglycerides concentrations also significantly correlated with the percent change in CBF and CAD. However, in a multiple regression analysis, log-transformed adiponectin concentration was the only independent predictor of the percent change in CBF and CAD (p<0.0001; p<0.0001, respectively). Furthermore, patients with adiponectin concentrations <6.3 mg/L demonstrated coronary endothelial dysfunction with high specificity both in terms of CBF and CAD response (85%; 88%, respectively).

CONCLUSIONS

Adiponectin is a better predictor of coronary endothelial function than other factors such as HOMA-R, body mass index, immunoreactive insulin, and triglycerides.

Prevalence of antibody to hepatitis E virus among wild sika deer, Cervus nippon, in Japan

We examined 976 sika deer serum samples, 159 liver tissue samples and 88 stool samples collected from 16 prefectures in Japan, and performed ELISA and RT-PCR assays to detect antibodies to HEV and HEV RNA, respectively. Although 25 (2.6%) of 976 samples were positive for anti-HEV IgG, the antibody titers were very low. The OD values ranged between 0.018 and 0.486, forming a single distribution rather than a bimodal distribution, suggesting that the antibody detected in this study was not induced by HEV infection, or that deer have low sensitivity to HEV. HEV RNA was not detected in these samples, also suggesting that deer may not play a role as an HEV reservoir.

Association between Toll-like receptors and the extent and severity of coronary artery disease in patients with stable angina

OBJECTIVES

Toll-like receptors mediate the innate immune response triggered by pathogen-associated molecular patterns, and atherosclerosis can be considered a state of chronic inflammation whereby immune system cells accumulate within the intima of the arterial wall. The goal of this study was to determine the relation of Toll-like receptors to the extent and severity of coronary artery disease.

METHODS

Angiographic vessel score and Gensini score were used to evaluate the extent and severity of coronary atherosclerosis. Sixty-two consecutive patients with stable angina were grouped as follows: those with insignificant (<50%) coronary stenosis (group 1), and those with 1 (group 2), 2 (group 3), or 3-vessel disease (group 4). The expression of Toll-like receptor 1, 2, and 4 on circulating CD14+ monocytes was analyzed by flow-cytometry in all patients.

RESULTS

Toll-like receptor 2 had a positive correlation with the vessel score and Gensini score (r=0.46, P<0.001; r=0.32, P<0.02, respectively). Toll-like receptor 4 also positively correlated with the vessel score and Gensini score (r=0.47, P<0.001; r=0.29, P<0.05, respectively). No significant correlation existed between the expression of Toll-like receptor 1 and the vessel score or Gensini score. Further, there was no significant correlation between high-sensitivity C-reactive protein and the vessel score or Gensini score.

CONCLUSION

These data suggest that Toll-like receptor 2 and 4 expression correlates with the extent and severity of coronary artery disease.