Further antinociceptive effects of myricitrin in chemical models of overt nociception in mice

The present work explored the antinociceptive effects of the flavonoid myricitrin in models of overt nociception triggered by intraplantar injection of chemical algogens into the hind paw of mice. The nociception induced by bradykinin (3 nmol/paw i.pl.) was abolished by prior treatment with myricitrin (10–100 mg/kg, i.p.) with ID₅₀ of 12.4 (8.5–18.1) mg/kg. In sharp contrast, myricitrin failed to affect the nociception elicited by prostaglandin E₂ (3 nmol/paw i.pl.). Cinnamaldehyde (10 nmol/paw i.pl.)-induced nociception was reduced by myricitrin (100 mg/kg, i.p.) and camphor (7.6 mg/kg, s.c.) in 43 ± 10% and 57 ± 8%, respectively. Myricitrin (30–100 mg/kg, i.p.) and amiloride (100 mg/kg, i.p.) inhibited nociceptive responses induced by acidified saline (pH 5/paw i.pl.), with ID₅₀ of 22.0 (16.1–30.0) mg/kg and inhibition of 71 ± 6% and 64 ± 5%, respectively. Moreover, myricitrin (10–30 mg/kg, i.p.) and ruthenium red (3 mg/kg, i.p.) significantly reduced the nociception induced by menthol (1.2 μmol/paw i.pl.) with the mean ID₅₀ of 2.4 (1.5–3.7) mg/kg and inhibition of 95 ± 3% and 51 ± 7%, respectively. In addition, myricitrin administration (30 and 100 mg/kg, i.p.) markedly reduced menthol-induced mechanical allodynia. However, myricitrin (100 mg/kg, i.p.) prevented (only in time of 60 min) cold allodynia induced by menthol. Collectively, the present results extend prior data and show that myricitrin promotes potent antinociception, an action that is likely mediated by an inhibition of the activation of nociceptors by bradykinin and TRPs agonist (i.e. cinnamaldehyde, acidified saline and menthol), probably via inhibition of PKC pathways. Thus, myricitrin could constitute an attractive molecule of interest for the development of new analgesic drugs.     

Genetic associations with acute stress-related changes in eating in the absence of hunger

Background

Acute psychological stress is associated with eating in the absence of hunger.

Objective

To investigate if BclI and FTO polymorphisms are associated with eating in the absence of hunger as a result of acute psychological stress.

Methods

FTO (rs9939609) and BclI were genotyped in 98 subjects (BMI = 23.9 ± 3.3 kg/m²). In a randomized crossover design, the ‘eating in absence of hunger’ protocol was measured as a function of acute stress vs. a control task and of STAI (State Trait Anxiety Index) state scores.

Results

In comparison with the FTO T allele, the A allele was associated with an increased feelings of hunger after food intake in the stress (11 ± 10 vs. 18 ± 15, p < 0.01) and control condition (12 ± 9 vs. 16 ± 12, p < 0.05), even though food intake was not different. For the first time, it was observed that in comparison to the BclI C/C genotype, the BclI G/G genotype was associated with higher STAI states scores at 0, 10, and 20 min after the stress condition (30.8 ± 6.4 vs. 36.3 ± 8.2; 28.3 ± 5.5 vs. 32.3 ± 7.5; 27.7 ± 6.1 vs. 31.2 ± 7.5, p < 0.05). Additionally, the BclI G/G genotype was associated with a larger difference in energy intake between the stress and control condition, in comparison with the BclI C/C genotype (136.6 ± 220.4 vs. 29.4 ± 176.3 kJ, p < 0.04).

Conclusion

In concordance with previous studies, the FTO A allele is related to a lower feeling of hunger after a standardized meal. For the first time, the BclI G/G genotype is shown to be associated with increased sensitivity to psychological stress, and increased eating in the absence of hunger after stress.

Practice implications

Interventions to reduce body weight should consider the subjects’ genetic background.     

Variations in arterioles in spontaneously hypertensive rats

Summary In the present study, the diameters of afferent and efferent arterioles of kidneys from spontaneously hypertensive rats (SHR) were evaluated and compared with those from Wistar Kyoto rats (WKY) using a vascular cast model. At 4 weeks of age, the blood pressure was slightly higher in SHR than in WKY (124±1 vs 116±7 mmHg, ns). The diameters of afferent arterioles in SHR were smaller than those in WKY (10.3±0.6 vs 12.3±0.7 µm,P<0.001), whereas the diameters of efferent arterioles were comparable in the two strains. At 20 weeks of age, the blood pressure was markedly elevated in SHR than in WKY (192±5 vs 140±4 mmHg,P<0.001). The diameters of afferent arterioles in SHR at this age were much smaller than those in WKY (14.3±0.5 vs 17.1±0.6 µm,P<0.01). The diameters of efferent arterioles in SHR were, however, larger than those in WKY (15.4±l.2 vs 12.9±0.4 µm,P< 0.05). The net effect of these changes in arteriolar size helps to maintain normal intraglomerular pressure and to protect glomeruli from damage due to hypertension.     

Stress augments food 'wanting' and energy intake in visceral overweight subjects in the absence of hunger

Stress may induce eating in the absence of hunger, possibly involving changes in food reward, i.e. ‘liking’ and ‘wanting’. The objective of this study was to assess the effects of acute psychological stress on food reward, and on energy intake, in visceral overweight (VO) vs. normal weight (NW) subjects. Subjects (27 NW, age = 26 ± 9 yrs, BMI = 22 ± 2 kg/m²; 15 VO, age = 36 ± 12 yrs, BMI = 28 ± 1 kg/m²) came to the university twice, fasted, for either a rest or stress condition (randomized cross-over design). Per test-session ‘liking’ and ‘wanting’ for 72 items divided in six categories (bread, filling, drinks, dessert, snacks, and stationery (control)) were measured twice, each time followed by a wanted meal. Appetite profile (visual analogue scales, VAS), heart rate, mood state and level of anxiety (POMS/STAI questionnaires) were measured.High hunger and low satiety (64 ± 19, 22 ± 20 mmVAS) confirmed the fasted state. Elevated heart rate, anger and confusion scores (p ≤ 0.03) confirmed the stress vs. rest condition. Consumption of the first meal decreased hunger, increased satiety, and decreased ranking of ‘liking’ of bread vs. increased ranking of ‘liking’ of the control (p < 0.001). ‘Wanting’ for dessert and snacks, energy intake, carbohydrate and fat intake for the second meal stress vs. rest relatively increased in VO vs. decreased in NW (p < 0.02). During stress vs. rest VO showed a 6 ± 9% increase in percentage of daily energy requirements consumed over the two meals (p = 0.01).To conclude, visceral overweight subjects showed stress-induced food intake in the absence of hunger, resulting in an increased energy intake.     

High interindividual variability in urinary fosfomycin concentrations in healthy female volunteers

ObjectivesFosfomycin is increasingly being prescribed for treatment of uncomplicated urinary tract infections in an era of emerging drug resistance. Surprisingly, little is known of the urinary concentrations of fosfomycin and its interindividual variation after the standard single 3-g oral dose. We aimed to gain more insight into urinary fosfomycin pharmacokinetics to evaluate its effectiveness.MethodsThree grams of fosfomycin trometamol was administered to 40 healthy female volunteers with an estimated mean glomerular filtration rate of >90 mL/min/1.73m². Urine samples were collected from every urination during 48 hours, and then twice daily for up to 7 days. Time, volume, and pH were recorded. Concentrations were quantified with UPLC-MS/MS. Effectiveness was evaluated based on urinary concentrations and the target MIC of E. coli, the most common uropathogen.ResultsA high interindividual variability was found. Peak concentration was 1982.0 ± 1257.4 mg/L, urinary half-life 12.4 ± 5.7 hours, and excretion rate over 48 hours 29.9 ± 7.1 mg/h. Recovery was 44.5 ± 12.6% after 48 hours and 47.0 ± 10.4% after 7 days. Concentrations remained above the EUCAST breakpoint of 32 mg/L in 100% of the volunteers over the first 24 hours, 67.5% for 48 hours, and 30% for 72 hours. A high urinary output was associated with low urinary concentrations and consequently reduced time > MIC, AUC_0-7days/MIC, and C_max/MIC values.ConclusionsConsiderable interindividual variability observed in the pharmacokinetics of fosfomycin signifies a risk for inadequate drug exposure in a significant proportion of the population. The current dosing regimen should therefore be reevaluated.     

Histamine is not released in acute thermal injury in human skin in vivo: a microdialysis study

Background  Animal models have shown histamine to be released from the skin during the acute phase of a burn injury. The role of histamine during the early phase of thermal injuries in humans remains unclear. Purpose  The objectives of this trial were to study histamine release in human skin during the acute phase of a standardized thermal injury in healthy volunteers. Methods  Histamine concentrations in human skin were measured by skin microdialysis technique. Microdialysis fibers were inserted into the dermis in the lower leg in male healthy volunteers. A standardized superficial thermal injury was elicited by a heating thermode (49°C) applied to the skin for 5 min. Histamine in dialysate was analyzed for up to 2 h after the injury using two different analytical methods. Results  Spectrofluorometric assay of histamine showed no histamine release in separate studies using 2-min samples over 20 min (n = 6) and 5–10-min samples over 120 min (n = 8). The histamine values were at the limits of the quantification limit of the spectrofluorometric assay. Confirmatory studies using a sensitive radioimmunoassay confirmed no histamine release within the first hour of a thermal injury (baseline 11.6 ± 1.8 nM vs. post-burn values of 14.8 ± 1.8 nM, n = 8). Conclusions  Histamine is not released in human skin during the acute phase of a thermal injury.     

Changes in heart rate recovery after high-intensity training in well-trained cyclists

Heart rate recovery (HRR) after submaximal exercise improves after training. However, it is unknown if this also occurs in already well-trained cyclists. Therefore, 14 well-trained cyclists (VO_2max 60.3 ± 7.2 ml kg⁻¹ min⁻¹; relative peak power output 5.2 ± 0.6 W kg⁻¹) participated in a high-intensity training programme (eight sessions in 4 weeks). Before and after high-intensity training, performance was assessed with a peak power output test including respiratory gas analysis (VO_2max) and a 40-km time trial. HRR was measured after every high-intensity training session and 40-km time trial. After the training period peak power output, expressed as W kg⁻¹, improved by 4.7% (P = 0.000010) and 40-km time trial improved by 2.2% (P = 0.000007), whereas there was no change in VO_2max (P = 0.066571). Both HRR after the high intensity training sessions (7 ± 6 beats; P = 0.001302) and HRR after the 40-km time trials (6 ± 3 beats; P = 0.023101) improved significantly after the training period. Good relationships were found between improvements in HRR_40-km and improvements in peak power output (r = 0.73; P < 0.0001) and 40-km time trial time (r = 0.96; P < 0.0001). In conclusion, HRR is a sensitive marker which tracks changes in training status in already well-trained cyclists and has the potential to have an important role in monitoring and prescribing training.     

Comparison of serum enzyme activity in great sturgeon, Huso huso, cultured in brackish and freshwater earth ponds in Iran

Blood samples were collected from 60 great sturgeons, Huso huso, to establish the following serum enzyme activity: aspartate amino-transferase (AST), alanine amino-transferase (ALT), lactic acid dehydrogenase (LDH), creatine kinase (CK), and alkaline phosphatase (ALP) using an autoanalyzer, and acid phosphatase (ACP) by manual method. Thirty 5-year-old cultured fish were caught from each of two sites; a brackish-water earth pond in Bafgh and a freshwater pond in Gorgan in the centre and northeast of Iran, during May 2006. Results of the serum enzymes activity for H. huso samples from Bafgh and Gorgan were: AST, 502.9 ± 258.2 and 436.1 ± 186.8; ALT, 104.4 ± 35.1 and 53.1 ± 38.7; LDH, 3094.2 ± 1277.5 and 2486.3 ± 1393.3; CK, 3632.9 ± 2618.7 and 3967 ± 5054.9; ALP, 281.2 ± 112.7 and 762.2 ± 600.2; ACP, 13.3 ± 2.5 and 33 ± 6.8 IU/L. Mean values of ALT, ALP and ACP were significantly different in the fish from the two sites (p < 0.05). These results may be used to understand some biological (e.g., serum enzyme activity) and ecological characteristics of cultured H. huso.     

Pathology of testis and epididymis in native goats in southern Iran

A slaughterhouse-based survey was conducted to determine the type and the prevalence of lesions in the testis and epididymis of native bucks reared in southern Iran. Testis, epididymis, and tunica, which belonged to 425 bucks of various age groups, were inspected. The specimens were collected randomly during a 6-month period. Various abnormalities in testis and the epididymis were observed. Grossly, testicular mineralization was the most prevalent abnormality (n = 183, 45%) followed by degeneration or hypoplasia (n = 26, 6.4%), adhesion (n = 20, 4.9%), cryptorchidism (n = 12, 2.9%), congenital testicular cyst (n = 9, 2.2%), abscess (n = 4, 0.9%), and orchitis (n = 1, 0.2%). As the age of the bucks increased, the percentages of mineralization increased significantly (p < 0.05). Based on the results of the gross examination, congenital epididymal cysts were the most prevalent abnormality (n = 57, 14.4%) then followed by epididymal abscess (n = 12, 2.9%), melanosis (n = 10, 2.5%), and epididymitis (n = 3, 0.7%). Congenital epididymal cysts, 1 to 2 mm in diameter, were mostly located on the head of the epididymis. On histopathological examination, mineralization showed the highest prevalence rate in testis followed by hypoplasia and degeneration, besnoitiosis, orchitis, and edema. Besnoitiosis was also the predominant lesion in the head and tail of the epididymis followed by epididymitis, hypoplasia or degeneration, melanosis, and sperm granuloma. Besnoitia cysts were found in 11.3% of the testes, 14.1% of the epididymal heads, and 7.5% of the epididymal tails.     

Changes in plasma concentrations of interleukin-6 and interleukin-1 receptor antagonists in response to adrenaline infusion in humans

To investigate the possible role of adrenaline in the response of interleukin (IL)-6 and IL-1 receptor antagonists (ra) to extreme physiological conditions such as trauma and exercise, we examined the concentrations in the plasma of these cytokines during an adrenaline infusion. Given the fact that HIV infected patients have elevated levels of IL-6 in plasma, 12 HIV seropositive subjects and 6 HIV seronegative control subjects received a 1-h adrenaline infusion. Baseline concentrations of IL-6 and IL-1ra were higher in the HIV patients compared with the controls (P < 0.05 and P < 0.01, respectively), being most pronounced in the untreated subgroup of HIV infected patients (n=6). The plasma concentration of adrenaline had increased 24-fold after 15 min of adrenaline infusion. The plasma concentration of IL-6 had increased by two- to threefold after 45 min of adrenaline infusion (P < 0.01) and was still elevated 1 h after the infusion had ended (P < 0.001 and P < 0.05 in controls and HIV infected patients, respectively). The plasma concentration of IL-1ra had increased two- to threefold 1 h after ceasing the adrenaline infusion (P < 0.05 and P < 0.01 in controls and HIV infected patients, respectively). The relative increase in the cytokine levels was similar in controls and HIV infected patients. Thus, HIV infection did not influence the effect of adrenaline on IL-6 and IL-1ra. The present study supports the existence of a relationship between the plasma concentration of adrenaline and IL-6. It is possible that an increased adrenaline concentration in plasma induces a continued de novo synthesis of IL-6, thereby increasing plasma IL-6 in a time–dose dependent manner. Accepted: 16 April 2000     

Involvement of neuronal nitric oxide synthase in cognitive impairment in isoflurane-treated rats

The underlying causes of post-operative cognitive dysfunction (POCD) in elderly patients remain to be elucidated. In order to explore possible contributory mechanisms, we tested the effects of isoflurane anesthesia on (i) expression of hippocampal neuronal nitric oxide synthase (nNOS) and (ii) the relationship of changes in nNOS expression to cognitive dysfunction in isoflurane-treated aged rats. Our results indicate that isoflurane treatment leads to significant changes in correct reactions (F = 28.35, p < 0.001), initiative avoidances (F = 29.33, p < 0.001), and total reaction time (TRT) (F = 6.99, p < 0.05) of treated rats in the Y-maze test. Isoflurane-treated rats had fewer correct reactions and initiative avoidances in the Y-maze test 24 and 48 h after 2 h of isoflurane anesthesia compared with control group rats (p < 0.05). TRTs to complete 20 trials of the Y-maze test increased significantly 48 h after 2 h anesthesia. The number of nNOS-positive hippocampal neurons decreased 24 h after anesthesia, corresponding to an increased mean immunostaining grey-scale value. These data show that isoflurane causes a transient decrease in expression of hippocampal nNOS in aged rats during early post-anesthesia stages, and that the transient decrease of nNOS is closely correlated with cognitive impairment in isoflurane-treated aged rats.     

Kinetic study of free radicals trapped in dental resins stored in different environments

In this work, we used electron paramagnetic resonance to follow the decrease kinetics of free radicals trapped in an experimental resin (ER) and in a commercial composite (Charisma^® (Ch)) stored under different conditions (in air at 25 and 37 °C; in argon, oxygen and water at 25 °C). During the first day, the decay was fast (0–24 h—rate of decay of allylic radical: 1700–1000 a.u. for Ch, 1700–1500 a.u. for ER) and the storage conditions had no influence on the kinetics. This phase was ascribed to a post-polymerization phenomenon. From 1 day to 1 month, the rate of decay depended on the storage environment. In argon, free radicals were quite stable (1 day to 1 month—rate of decay of allylic radical: 1200–1000 a.u. for Ch, 1400–1200 a.u. for ER). For the other storage environments, in ER, the rate of decay was higher in water than in oxygen and in air (1 day to 1 month—rate of decay of allyl radical: 1400 a.u. to 100, 500 and 800 a.u., respectively). In Ch, free radicals faded quicker than in ER, as undetectable levels were reached before 1 month, which attests to the influence of fillers on radical decrease kinetics. Heating experiments were also performed, and free radical concentrations decreased faster at higher temperatures, especially above the glass transition temperature. In conclusion, ambient oxygen is mainly involved in the termination process of free radicals. Therefore, conditions influencing oxygen diffusion have an impact on radical kinetics as well.     

Alterations in the expression and activity of creatine kinase-M and mitochondrial creatine kinase subunits in skeletal muscle following prolonged intense exercise in rats

Creatine kinase (CK) isoenzymes are important structural and energy metabolism components in skeletal muscle. In this study, CK isoenzyme alterations were examined in male rats, with an 8% body mass weight attached to their tail. The rats were either forced to swim for 5 h (5S, n = 51), or were pre-trained for 8 days and then forced to swim for 5 h (T5S, n = 48). Rats were sacrificed either immediately (0 h PS), 3 h (3 h PS), or 48 h post-swimming (48 h PS). Serum CK was increased significantly (P < 0.01) 6.2- and 2.0-fold at 0 h PS following the 5S and T5S protocols, respectively. However, training (T5S protocol) significantly (P < 0.01) decreased CK release. Soleus and white gastrocnemius (WG) CK activity was significantly decreased following the 5S protocol (P < 0.05), but not following the T5S protocol. The CK-M activity of the soleus muscle was significantly (P < 0.05) decreased at 0 h PS following both the 5S and T5S protocols, and returned to control values at 3 h PS. The CK-M activity of the WG was significantly (P < 0.05) decreased at 0 h PS following the 5S protocol. Sarcomeric mitochondrial CK (sCK-Mit) was decreased significantly (P < 0.01) at 0 h PS (20%), 3 h PS (14%), 24 h PS (22%), and 48 h PS (15%) following the 5S protocol. However, sCK-Mit was decreased significantly (P < 0.01) only at 0 h PS (7%) following the T5S. The results of this study demonstrate that prolonged intense exercise causes a loss of skeletal muscle CK-M and sCK-Mit activity and that training prior to the prolonged intense exercise attenuates the exercise-induced CK-M and sCK-Mit loss in both red and white skeletal muscles. Accepted: 18 July 1999     

Exercise-induced shear stress is associated with changes in plasma von Willebrand factor in older humans

Shear stress is the frictional force of blood against the endothelium, a stimulus for endothelial activation and the release of von Willebrand factor (vWF). This study tested the hypothesis that the increase in shear stress associated with exercise correlates with plasma vWF. Young (n = 14, 25.7 ± 5.4 years) and older (n = 13, 65.6 ± 10.7 years) individuals participated in 30 min of dynamic handgrip exercise at a moderate intensity. Brachial artery diameter and blood flow were measured using ultrasound Doppler and blood samples were collected before, immediately after, and following 30 min of recovery from exercise with plasma levels of vWF. Plasma levels of vWF increased (P < 0.05) by 6 ± 2% in young individuals and 4 ± 1% in older individuals immediately after exercise. The change in plasma vWF was linearly correlated with the increase in shear stress during exercise in older individuals (post-exercise: r = 0.78, 30 min recovery: r = 0.77, P < 0.01), but no association was found in the young individuals. These changes in plasma levels of vWF in humans suggest that aging influences endothelial activation and hemostasis.     

Decline in genomic DNA methylation through aging in a cohort of elderly subjects

Loss of genomic DNA methylation has been found in a variety of common human age-related diseases. Whether DNA methylation decreases over time as individuals age is unresolved. We measured DNA methylation in 1097 blood DNA samples from 718 elderly subjects between 55 and 92 years of age (1-3 samples/subjects), who have been repeatedly evaluated over an 8-year time span in the Boston area Normative Aging Study. DNA methylation was measured using quantitative PCR-Pyrosequencing analysis in Alu and LINE-1 repetitive elements, heavily methylated sequences with high representation throughout the human genome.Age at the visit was negatively associated with Alu element methylation (β = −0.12 %5 mC/year, p = 0.0005). A weaker association was observed with LINE-1 elements (β = −0.06 %5 mC/year, p = 0.049). We observed a significant decrease in average Alu methylation over time, with a −0.2 %5 mC change (p = 0.012) compared to blood samples collected up to 8 years earlier. The longitudinal decline in Alu methylation was linear and highly correlated with time since the first measurement (β = −0.089 %5 mC/year, p < 0.0001). In contrast, average LINE-1 methylation did not vary over time [p = 0.51]. Our results demonstrate a progressive loss of DNA methylation in repetitive elements dispersed throughout the genome.     

Autoregulative function in the brain in an endotoxic rat shock model

Objective and design:  Autoregulative function in the brain gets relevant in hypodynamic conditions of a sepsis syndrome. We investigated the temporal pattern and dose dependent effects of LPS-induced shock on autoregulative function in rats. Material and subjects:  Chloralose-anesthetized and mechanically ventilated male CD-rats (n = 30). Treatment:  Animals were subjected to vehicle, 1 or 5 mg/kg b.w. lipopolysaccharide (LPS) from E. coli given intravenously. Methods:  Autoregulative function was tested repeatedly with a carotid compression technique assessing the transient hyperemic response ratio (THRR) in the cortex with laser Doppler flowmetry up to 270 min. THRR data from exsanguination experiments served as controls. Results:  Despite lower blood pressure levels in the high dose group (control: 114 ± 7 mmHg; 1 mg/kg LPS group: 82 ± 16 mmHg; 5 mg/kg LPS group: 62 ± 16 mmHg; p < 0.05) progressive cerebral hyperemia occurred similarly in both groups. Compared to exsanguinations experiments autoregulative compensation for lower blood pressure levels was lacking in the high LPS dose group at the end of experiments. Conclusions:  Cerebral autoregulation was affected by LPS-induced shock supporting the notion of vasoregulative failure in endotoxic shock Received 22 October 2007; returned for revision 20 February 2008; received from final revision 23 May 2008; accepted by K. Visvanathan 8 July 2008     

Dyspnea on exertion in obese men

Recently, we reported that dyspnea on exertion is strongly associated with an increased oxygen cost of breathing in otherwise healthy obese women; the mechanism of dyspnea on exertion in obese men is unknown. Obese men underwent measurements of body composition, fat distribution, pulmonary function, steady state and maximal graded cycle ergometry, and oxygen cost of breathing. Nine men (34 ± 8 years, 35 ± 4 BMI) with ratings of perceived breathlessness of ≤2 during cycling, and ten men (36 ± 9 years, 38 ± 5 BMI) with ratings of perceived breathlessness ≥4 were studied (ratings of perceived breathlessness: 1.8 ± 0.4 vs. 4.7 ± 0.8, respectively; p < 0.0001). Groups had only minor differences in fat distribution, pulmonary function, and steady state exercise. There was no association between ratings of perceived breathlessness and oxygen cost of breathing; but ratings of perceived breathlessness was strongly correlated with ratings of perceived exertion (RPE, rho = 0.87, p < 0.0001). The differences in exercise intensity, ventilatory demand, cardiovascular conditioning and/or the quality of respiratory sensation did not appear to play a role in the development of dyspnea on exertion. The mechanism of dyspnea on exertion in obese men seems unrelated to the oxygen cost of breathing.     

Effectiveness of Varicella Vaccination Program in Preventing Laboratory-Confirmed Cases in Children in Seoul,Korea

A universal one-dose varicella vaccination program was introduced in 2005 in Republic of Korea. However, the incidence of varicella in Korea has tripled over the last decade. We conducted a community based 1:1 matched case-control study to assess the effectiveness of one MAV strain-based vaccine and three Oka strain-based vaccines licensed for use in Korea. All cases were children in Seoul, Korea with varicella who were reported to the National Notifiable Disease Surveillance System in Seoul during 2013. The controls were age-matched children with mumps or scarlet fever but no history of varicella. We included 537 cases and 537 controls. The overall effectiveness of one dose of varicella vaccination was 13% (95% confidence interval [CI], −17.3–35.6). Of the four licensed varicella vaccines, only one was highly effective (88.9%; 95% CI, 52.1–97.4). The vaccine effectiveness for the other vaccines were 71.4% (95% CI, −37.5–94.1), −5% (95% CI, −61.9–31.9), and −100% (95% CI, −700–50.0). The overall effectiveness of vaccination was 75.8% (95% CI, 22.8–92.4) in the first year after vaccination and decreased thereafter; the effectiveness became −7.2% (95% CI, −130.9–59.2) in the fourth year after vaccination. Further studies are warranted to investigate reduced effectiveness of varicella vaccines in Korea.     

The relationship between monocarboxylate transporters 1 and 4 expression in skeletal muscle and endurance performance in athletes

The purpose of this study was to examine the relationship between skeletal muscle monocarboxylate transporters 1 and 4 (MCT1 and MCT4) expression, skeletal muscle oxidative capacity and endurance performance in trained cyclists. Ten well-trained cyclists (mean ± SD; age 24.4 ± 2.8 years, body mass 73.2 ± 8.3 kg, VO_2max 58 ± 7 ml kg⁻¹ min⁻¹) completed three endurance performance tasks [incremental exercise test to exhaustion, 2 and 10 min time trial (TT)]. In addition, a muscle biopsy sample from the vastus lateralis muscle was analysed for MCT1 and MCT4 expression levels together with the activity of citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD). There was a tendency for VO_2max and peak power output obtained in the incremental exercise test to be correlated with MCT1 (r = −0.71 to −0.74; P < 0.06), but not MCT4. The average power output (P _average) in the 2 min TT was significantly correlated with MCT4 (r = −0.74; P < 0.05) and HAD (r = −0.92; P < 0.01). The P _average in the 10 min TT was only correlated with CS activity (r = 0.68; P < 0.05). These results indicate the relationship between MCT1 and MCT4 as well as cycle TT performance may be influenced by the length and intensity of the task.     

Skin microvascular reactivity in trained adolescents

Whilst endothelial dysfunction is associated with a sedentary lifestyle, enhanced endothelial function has been documented in the skin of trained individuals. The purpose of this study was to investigate whether highly trained adolescent males possess enhanced skin microvascular endothelial function compared to their untrained peers. Seventeen highly and predominantly soccer trained boys ( [(V)\dot]\textO_2 \textpeak \dot{V}{\text{O}}_{{2\,{\text{peak}}}} : 55 ± 6 mL kg⁻¹ min⁻¹) and nine age- and maturation-matched untrained controls ( [(V)\dot]\textO_2 \textpeak \dot{V}{\text{O}}_{{2\,{\text{peak}}}} : 43 ± 5 mL kg⁻¹ min⁻¹) aged 13–15 years had skin microvascular endothelial function assessed using laser Doppler flowmetry. Baseline and maximal thermally stimulated skin blood flow (SkBF) responses were higher in forearms of trained subjects compared to untrained participants [baseline SkBF: 11 ± 4 vs. 9 ± 3 perfusion units (PU), p < 0.05; SkBF_max: 282 ± 120 vs. 204 ± 68 PU, p < 0.05]. Similarly, cutaneous vascular conductance (CVC) during local heating was superior in the forearm skin of trained versus untrained individuals (CVC_max: 3 ± 1 vs. 2 ± 1 PU mmHg⁻¹, p < 0.05). Peak hyperaemia following arterial occlusion and area under the reactive hyperaemia curve were also greater in forearm skin of the trained group (peak hyperaemia: 51 ± 21 vs. 35 ± 15 PU, p < 0.05; area under curve: 1596 ± 739 vs. 962 ± 796 PUs, p < 0.05). These results suggest that chronic exercise training in adolescents is associated with enhanced microvascular endothelial vasodilation in non-glabrous skin.