The exercise pressor reflex - a pressure-raising mechanism with a limited role in regulating leg perfusion during locomotion in young healthy men

We investigated the role of the exercise pressor reflex (EPR) in regulating the haemodynamic response to locomotor exercise. Eight healthy participants (23 ± 3 years,V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ : 49 ± 6 ml/kg/min) performed constant-load cycling exercise (∼36/43/52/98%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ; 4 min each) without (CTRL) and with (FENT) lumbar intrathecal fentanyl attenuating group III/IV locomotor muscle afferent feedback and, thus, the EPR. To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during FENT, subjects mimicked the ventilatory response recorded during CTRL. Arterial and leg perfusion pressure (femoral arterial and venous catheters), femoral blood flow (Doppler-ultrasound), microvascular quadriceps blood flow index (indocyanine green), cardiac output (inert gas breathing), and systemic and leg vascular conductance were quantified during exercise. There were no cardiovascular and ventilatory differences between conditions at rest. Pulmonary ventilation, arterial blood gases and oxyhaemoglobin saturation were not different during exercise. Furthermore, cardiac output (-2% to -12%), arterial pressure (-7% to -15%) and leg perfusion pressure (-8% to -22%) were lower, and systemic (up to 16%) and leg (up to 27%) vascular conductance were higher during FENT compared to CTRL. Leg blood flow, microvascular quadriceps blood flow index, and leg O2 -transport and utilization were not different between conditions (P > 0.5). These findings reflect a critical role of the EPR in the autonomic control of the heart, vasculature and, ultimately, arterial pressure during locomotor exercise. However, the lack of a net effect of the EPR on leg blood flow challenges the idea of this cardiovascular reflex as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals. KEY POINTS: The role of the exercise pressor reflex (EPR) in regulating leg O2 -transport during human locomotion remains uncertain. We investigated the influence of the EPR on the cardiovascular response to cycling exercise. Lumbar intrathecal fentanyl was used to block group III/IV leg muscle afferents and debilitate the EPR at intensities ranging from 30% to 100%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ . To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during exercise with blocked leg muscle afferents, subjects mimicked the ventilatory response recorded during control exercise. Afferent blockade increased leg and systemic vascular conductance, but reduced cardiac output and arterial-pressure, with no net effect on leg blood flow. The EPR influenced the cardiovascular response to cycling exercise by contributing to the autonomic control of the heart and vasculature, but did not affect leg blood flow. These findings challenge the idea of the EPR as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals.

Autonomic cardiovascular control during exercise

The cardiovascular response to exercise is largely determined by neurocirculatory control mechanisms that help to raise blood pressure and modulate vascular resistance which, in concert with regional vasodilatory mechanisms, promote blood flow to active muscle and organs. These neurocirculatory control mechanisms include a feedforward mechanism, known as central command, and three feedback mechanisms, namely, 1) the baroreflex, 2) the exercise pressor reflex, and 3) the arterial chemoreflex. The hemodynamic consequences of these control mechanisms result from their influence on the autonomic nervous system and subsequent alterations in cardiac output and vascular resistance. Although stimulation of the baroreflex inhibits sympathetic outflow and facilitates parasympathetic activity, central command, the exercise pressor reflex, and the arterial chemoreflex facilitate sympathetic activation and inhibit parasympathetic drive. Despite considerable understanding of the cardiovascular consequences of each of these mechanisms in isolation, the circulatory impact of their interaction, which occurs when various control systems are simultaneously activated (e.g., during exercise at altitude), has only recently been recognized. Although aging and cardiovascular disease (e.g., heart failure, hypertension) have both been recognized to alter the hemodynamic consequences of these regulatory systems, this review is limited to provide a brief overview on the action and interaction of neurocirculatory control mechanisms in health.

On the hemodynamic consequence of the chemoreflex and muscle mechanoreflex interaction in women and men: two tales, one story

KEY POINTS

The cardiovascular response resulting from the activation of the muscle mechanoreflex (MMR), or the chemoreflex (CR), was previously shown to be different between women and men; this study focused on the hemodynamic consequence of the interaction of these two sympathoexcitatory reflexes. MMR and CR were activated by passive leg movement and exposure to hypoxia (O₂ -CR), or hypercapnia (CO₂ -CR), respectively. Individual and interactive reflex effects on central and peripheral hemodynamics were quantified in healthy young women and men. In men, the MMR:O₂ -CR and MMR:CO₂ -CR interactions restricted peripheral hemodynamics, likely by potentiating sympathetic vasoconstriction. In women, the MMR:O₂ -CR interaction facilitated central and peripheral hemodynamics, likely by potentiating sympathetic vasodilation; however, the MMR:CO₂ -CR interaction was simply additive for the central and peripheral hemodynamics. The interaction between the MMR and the CR exerts a profound influence on the autonomic control of cardiovascular function in humans, with the hemodynamic consequences differing between women and men.

ABSTRACT

The cardiovascular response resulting from the individual activation of the muscle mechanoreflex (MMR), or the chemoreflex (CR), is different between men and women. Whether the hemodynamic consequence resulting from the interaction of these sympathoexcitatory reflexes is also sex-dependent remains unknown. MMR and CR were activated by passive leg movement (LM) and exposure to hypoxia (O₂ -CR), or hypercapnia (CO₂ -CR), respectively. Twelve young men and 12 young women completed two experimental protocols: 1) resting in normoxia (P_ET O₂ : ∼83mmHg, P_ET CO₂ : ∼34mmHg), normocapnic hypoxia (P_ET O₂ : ∼48mmHg, P_ET CO₂ : ∼34mmHg), and hyperoxic hypercapnia (P_ET O₂ : ∼524mmHg, P_ET CO₂ : ∼44mmHg); 2) LM under the same gas conditions. During the MMR:O₂ -CR coactivation, in men, the observed blood pressure (MAP) and cardiac output (CO) were not different (additive effect), while the observed leg blood flow (LBF) and vascular conductance (LVC) were significantly lower (hypo-additive), compared with the sum of the responses elicited by each reflex alone. In women, the observed MAP was not different (additive) while the observed CO, LBF, and LVC were significantly greater (hyper-additive), compared with the summated responses. During the MMR:CO₂ -CR coactivation, in men, the observed MAP, CO, and LBF were not different (additive), while the observed LVC was significantly lower (hypo-additive), compared with the summated responses. In women, the observed MAP was significantly higher (hyper-additive), while the observed CO, LBF, and LVC were not different (additive), compared with the summated responses. The interaction of the MMR and CR has a pronounced influence on the autonomic cardiovascular control, with the hemodynamic consequences differing between men and women. Abstract figure legend The chemoreflex and the muscle mechanoreflex are sympathoexcitatory mechanisms which, via neural feedback to the cardiovascular centre in the medulla, mediate neurocirculatory responses during physical activity. The interaction of the peripheral chemoreflex and muscle mechanoreflex potentiates vasoconstriction in men, but potentiates vasodilatation in women (left panel). The interaction of the central chemoreflex and muscle mechanoreflex also potentiates vasoconstriction in men, whereas the reflex interaction is simply additive for the vasomotor tone in women (right panel). This article is protected by copyright. All rights reserved.

Impact of aging on the work of breathing during exercise in healthy men

This study examined the impact of aging on the elastic and resistive components of the work of breathing (W_b) during locomotor exercise at a given 1) ventilatory rate, 2) metabolic rate, and 3) operating lung volume. Eight healthy younger (25 ± 4 yr) and 8 older (72 ± 6 yr) participants performed incremental bicycle exercise, from which retrospective analyses identified similar ventilatory rates (approximately 40, 70, and 100 L·min^-1), similar metabolic rates (V̇o₂: approximately 1.2, 1.6, and 1.9 L·min^-1), and similar lung volumes [inspiratory and expiratory reserve volumes (IRV/ERV: approximately 25/34%, 16/33%, and 13-34% of vital capacity]. W_b at each level was quantified by integrating the averaged esophageal pressure-volume loop, which was then partitioned into elastic and resistive components of inspiratory and expiratory work using the modified Campbell diagram. IRV was smaller in the older participants during exercise at ventilations of 70 and 100 L·min^-1 and during exercise at the three metabolic rates (P < 0.05). Mainly because of a greater inspiratory elastic and resistive W_b in the older group (P < 0.05), total W_b was augmented by 40%-50% during exercise at matched ventilatory and matched metabolic rates. When examined during exercise evoking similar lung volumes, total W_b was not different between the groups (P = 0.86). Taken together, although aging exaggerates total W_b during locomotor exercise at a given ventilatory or a given metabolic rate, this difference is abolished during exercise at a given operating lung volume. These findings highlight the significance of operating lung volume in determining the age-related difference in W_b during locomotor exercise.NEW & NOTEWORTHY This study evaluated the impact of aging on the work of breathing (W_b) during locomotor exercise evoking similar ventilatory rates, metabolic rates, and operating lung volumes in young and older individuals. Mainly because of a greater inspiratory elastic and resistive W_b in older participants, total W_b was higher during exercise at any given ventilatory and metabolic rate with aging. However, this age-related difference was abolished during exercise evoking similar operating lung volumes in both age groups. These findings highlight the significance of lung volumes in determining the age-related difference in total W_b.

On the implication of dietary nitrate supplementation for the hemodynamic and fatigue response to cycling exercise

This study investigated the impact of dietary nitrate supplementation on peripheral hemodynamics, the development of neuromuscular fatigue, and time to task failure during cycling exercise. Eleven recreationally active male participants (27 ± 5 yr, V̇o2max: 42 ± 2 mL/kg/min) performed two experimental trials following 3 days of either dietary nitrate-rich beetroot juice (4.1 mmol NO3-/day; DNS) or placebo (PLA) supplementation in a blinded, counterbalanced order. Exercise consisted of constant-load cycling at 50, 75, and 100 W (4 min each) and, at ∼80% of peak power output (218 ± 12 W), to task-failure. All participants returned to repeat the shorter of the two trials performed to task failure, but with the opposite supplementation regime (iso-time comparison; ISO). Mean arterial pressure (MAP), leg blood flow (QL; Doppler ultrasound), leg vascular conductance (LVC), and pulmonary gas exchange were continuously assessed during exercise. Locomotor muscle fatigue was determined by the change in pre to postexercise quadriceps twitch-torque (ΔQtw) and voluntary activation (ΔVA; electrical femoral nerve stimulation). Following DNS, plasma [nitrite] (∼670 vs. ∼180 nmol) and [nitrate] (∼775 vs. ∼11 μmol) were significantly elevated compared with PLA. Unlike PLA, DNS lowered both QL and MAP by ∼8% (P < 0.05), but did not alter LVC (P = 0.31). V̇O2 across work rates, as well as cycling time to task-failure (∼7 min) and locomotor muscle fatigue following the ISO-time comparison were not different between the two conditions (ΔQtw ∼42%, ΔVA ∼4%). Thus, despite significant hemodynamic changes, DNS did not alter the development of locomotor muscle fatigue and, ultimately, cycling time to task failure.NEW & NOTEWORTHY This study sought to characterize the impact of dietary nitrate supplementation on the hemodynamic response, locomotor muscle fatigue, and time to task failure during cycling exercise. Although nitrate supplementation lowered mean arterial pressure and exercising leg blood flow, leg vascular conductance and oxygen utilization were unaffected. Despite significant hemodynamic changes, there was no effect of dietary nitrate on neuromuscular fatigue development and, ultimately, cycling time to task failure.

On the Influence of Group III/IV Muscle Afferent Feedback on Endurance Exercise Performance

This review discusses evidence suggesting that group III/IV muscle afferents affect locomotor performance by influencing neuromuscular fatigue. These neurons regulate the hemodynamic and ventilatory response to exercise and, thus, assure appropriate locomotor muscle O2 delivery, which optimizes peripheral fatigue development and facilitates endurance performance. In terms of central fatigue, group III/IV muscle afferents inhibit motoneuronal output and thereby limit exercise performance.

The muscle reflex and chemoreflex interaction: ventilatory implications for the exercising human

We examined the interactive influence of the muscle reflex (MR) and the chemoreflex (CR) on the ventilatory response to exercise. Eleven healthy subjects (5 women/6 men) completed three bouts of constant-load single-leg knee-extension exercise in a control trial and an identical trial conducted with lumbar intrathecal fentanyl to attenuate neural feedback from lower-limb group III/IV muscle afferents. The exercise during the two trials was performed while breathing ambient air ([Formula: see text] ~97%, [Formula: see text]~84 mmHg, [Formula: see text] ~32 mmHg, pH ~7.39), or under normocapnic hypoxia ([Formula: see text] ~79%, [Formula: see text] ~43 mmHg, [Formula: see text] ~33 mmHg, pH ~7.39) or normoxic hypercapnia ([Formula: see text] ~98%, [Formula: see text] ~105 mmHg, [Formula: see text] ~50 mmHg, pH ~7.26). During coactivation of the MR and the hypoxia-induced CR (O₂-CR), minute ventilation (V̇e) and tidal volume (V_T) were significantly greater compared with the sum of the responses to the activation of each reflex alone; there was no difference between the observed and summated responses in terms of breathing frequency (f_B; P = 0.4). During coactivation of the MR and the hypercapnia-induced CR (CO₂-CR), the observed ventilatory responses were similar to the summated responses of the reflexes (P ≥ 0.1). Therefore, the interaction between the MR and the O₂-CR exerts a hyperadditive effect on V̇e and V_T and an additive effect on f_B, whereas the interaction between the MR and the CO₂-CR is simply additive for all ventilatory parameters. These findings reveal that the MR:CR interaction further augments the ventilatory response to exercise in hypoxia.NEW & NOTEWORTHY Although the muscle reflex and the chemoreflex are recognized as independent feedback mechanisms regulating breathing during exercise, the ventilatory implications resulting from their interaction remain unclear. We quantified the individual and interactive effects of these reflexes during exercise and revealed differential modes of interaction. Importantly, the reflex interaction further amplifies the ventilatory response to exercise under hypoxemic conditions, highlighting a potential mechanism for optimizing arterial oxygenation in physically active humans at high altitude.

[An epidemiological survey on clinical features, self-management and cognitive level of elderly asthmatics in China]

Objective: To investigate the prevalence of asthma among the elderly people in China and to analyze the clinical features, self-management and cognitive level of elderly asthma patients. Methods: According to the multi-stage random cluster sampling methods, a total of 164 215 subjects were visited by a questionnaire in the last epidemiology survey from eight provinces (Beijing, Shanghai, Guangdong, Liaoning, Henan, Shanxi, Jiangsu, Sichuan provinces) and seven regions (north, northeast, southern china, east, south, southwest and northwest) in China from February 2010 to August 2012. 2 034 were diagnosed as asthma. The elderly patients aged ≥65 years were selected from the 2 034 asthma patients. The clinical characteristics, comorbidities, the status of asthma control and self-management and insights of the disease in elderly asthma patients were analyzed. Results: Among the 2 034 asthma patients, 584 (28.7%) were elderly asthmatics aged ≥65 years old and 1 450 (71.3%) were<65 years old. In the elderly asthma group, Early-onset asthma accounted for 439 (75.2%) and 145 (24.8%) were late-onset. The common clinical manifestations of elderly asthma patients were: chest distress 395 (67.6%), wheezing 304 (52.1%), cough 298 (51.0%). Common comorbidities of elderly asthmatics were: chronic obstructive pulmonary disease 144 (24.7%), allergic rhinitis 122(20.9%), gastroesopheal reflux disease (GERD) 114(19.5%), allergic conjunctivitis 86 (14.7%), eczema 82 (14.0%), chronic bronchitis 76 (13.0%). The Asthma Control Test (ACT) scores of elderly asthmatics and non-elderly asthmatics were (18.5±3.2) and (21.7±3.4) respectively. There was a significant difference between the two groups (P=0.042). Of the elderly asthmatics, only 13 (2.2%) patients monitored daily using a peak flow meter. 93 (15.9%) patients aware that asthma was characterized by chronic airway inflammation. 64 (11.0%) asthmatics understood that the treatment goal. Conclusions: The clinical manifestations of elderly asthmatics are atypical, especially paroxysmal wheezing. Asthma in elderly people causes more comorbidities and mortality. The self-management and cognitive level of patients with asthma needs to be improved.

[A survey on clinical characteristics and risk factors of severe asthma in China]

Objective: To investigate the clinical characteristics and risk factors of severe bronchial asthma in Chinese people over 14 years old. Methods: According to the multi-stage random cluster sampling methods, a total of 164 215 subjects were visited by a questionnaire in the epidemiology survey from eight provinces (Beijing, Shanghai, Guangdong, Liaoning, Henan, Shanxi, Jiangsu, Sichuan provinces) located in seven regions (north, northeast, east, central China, south, southwest and northwest) of China from February 2010 to August 2012. A total of 2 034 were diagnosed as asthma. The clinical characteristics and related risk factors of patients with severe asthma in China were analyzed. Results: Among all asthma patients, 560 were newly diagnosed, accounting for 27.5% (560/2 034) and the percentage of previously confirmed patients was 72.5% (1 474/2 034). A total of 145 were eligible for severe asthma, accounting for 9.8% (145/1 474) of previously confirmed asthmatics and 7.1% (145/2 034) of all asthmatics. 83.5% (121/145) severe asthmatics had at least one trigger factor. Correlation analysis showed that the risk factors of severe asthma were: smoking (OR=1.543, 95%CI: 1.250-1.814), obesity (OR=2.186, 95%CI: 1.972-2.354), petting (OR=2.135, 95%CI: 1.904-2.283), combined with allergic rhinitis (OR=3.456, 95%CI: 2.721-4.326), gastroesophageal reflux disease (OR=1.842, 95%CI: 1.682-2.140), bronchiectasis (OR=1.665, 95%CI: 1.347-1.912) or chronic obstructive pulmonary disease (OR=1.312, 95%CI: 1.171-1.694). Conclusions: The most common comorbidities in severe asthmatics in China are allergic rhinitis and gastroesophageal reflux disease. The risk factors of severe asthma include obesity, allergic rhinitis, gastroesophageal reflux disease, chronic obstructive pulmonary disease, bronchiectasis, smoking and petting.

The exercise pressor reflex and chemoreflex interaction: cardiovascular implications for the exercising human

KEY POINTS

Although the exercise pressor reflex (EPR) and the chemoreflex (CR) are recognized for their sympathoexcitatory effect, the cardiovascular implication of their interaction remains elusive. We quantified the individual and interactive cardiovascular consequences of these reflexes during exercise and revealed various modes of interaction. The EPR and hypoxia-induced CR interaction is hyper-additive for blood pressure and heart rate (responses during co-activation of the two reflexes are greater than the summation of the responses evoked by each reflex) and hypo-additive for peripheral haemodynamics (responses during co-activation of the reflexes are smaller than the summated responses). The EPR and hypercapnia-induced CR interaction results in a simple addition of the individual responses to each reflex (i.e. additive interaction). Collectively, EPR:CR co-activation results in significant cardiovascular interactions with restriction in peripheral haemodynamics, resulting from the EPR:CR interaction in hypoxia, likely having the most crucial impact on the functional capacity of an exercising human.

ABSTRACT

We investigated the interactive effect of the exercise pressor reflex (EPR) and the chemoreflex (CR) on the cardiovascular response to exercise. Eleven healthy participants (5 females) completed a total of six bouts of single-leg knee-extension exercise (60% peak work rate, 4 min each) either with or without lumbar intrathecal fentanyl to attenuate group III/IV afferent feedback from lower limbs to modify the EPR, while breathing either ambient air, normocapnic hypoxia (S_a O₂ ∼79%, P_a O₂ ∼43 mmHg, P_a CO₂ ∼33 mmHg, pH ∼7.39), or normoxic hypercapnia (S_a O₂ ∼98%, P_a O₂ ∼105 mmHg, P_a CO₂ ∼50 mmHg, pH ∼7.26) to modify the CR. During co-activation of the EPR and the hypoxia-induced CR (O₂ -CR), mean arterial pressure and heart rate were significantly greater, whereas leg blood flow and leg vascular conductance were significantly lower than the summation of the responses evoked by each reflex alone. During co-activation of the EPR and the hypercapnia-induced CR (CO₂ -CR), the haemodynamic responses were not different from the summated responses to each reflex response alone (P ≥ 0.1). Therefore, while the interaction resulting from the EPR:O₂ -CR co-activation is hyper-additive for blood pressure and heart rate, and hypo-additive for peripheral haemodynamics, the interaction resulting from the EPR:CO₂ -CR co-activation is simply additive for all cardiovascular parameters. Thus, EPR:CR co-activation results in significant interactions between cardiovascular reflexes, with the impact differing when the CR activation is achieved by hypoxia or hypercapnia. Since the EPR:CR co-activation with hypoxia potentiates the pressor response and restricts blood flow to contracting muscles, this interaction entails the most functional impact on an exercising human.

Pharmacological attenuation of group III/IV muscle afferents improves endurance performance when oxygen delivery to locomotor muscles is preserved

We sought to investigate the role of group III/IV muscle afferents in limiting endurance exercise performance, independently of their role in optimizing locomotor muscle O₂ delivery. While breathing 100% O₂ to ensure a similar arterial O₂ content ([Formula: see text]) in both trials, eight male cyclists performed 5-km time trials under control conditions (H_CTRL) and with lumbar intrathecal fentanyl (H_FENT) impairing neural feedback from the lower limbs. After each time trial, common femoral artery blood flow (FBF) was quantified (Doppler ultrasound) during constant-load cycling performed at the average power of the preceding time trial. The assessment of end-tidal gases, hemoglobin content and saturation, and FBF facilitated the calculation of leg O₂ delivery. Locomotor muscle activation during cycling was estimated from vastus lateralis EMG. With electrical femoral nerve stimulation, peripheral and central fatigue were quantified by pre- to postexercise decreases in quadriceps twitch torque (ΔQ_tw) and voluntary activation (ΔVA), respectively. FBF (~16 mL·min^-1·W^-1; P = 0.6), [Formula: see text] (~24 mL O₂/dL; P = 0.9), and leg O₂ delivery (~0.38 mL O₂·min^-1·W^-1; P = 0.9) were not different during H_CTRL and H_FENT. Mean power output and time to completion were significantly improved by 9% (~310 W vs. ~288 W) and 3% (~479 s vs. ~463 s), respectively, during H_FENT compared with H_CTRL. Quadriceps muscle activation was 9 ± 7% higher during H_FENT compared with H_CTRL (P < 0.05). ΔQ_tw was significantly greater in H_FENT compared with H_CTRL (54 ± 8% vs. 39 ± 9%), whereas ΔVA was not different (~5%; P = 0.3) in both trials. These findings reveal that group III/IV muscle afferent feedback limits whole body endurance exercise performance and peripheral fatigue by restricting neural activation of locomotor muscle.NEW & NOTEWORTHY Group III/IV muscle afferent feedback facilitates endurance performance by optimizing locomotor muscle O₂ delivery but also limits performance by restricting neural drive to locomotor muscle. To isolate the performance-limiting effect of these sensory neurons, we pharmacologically attenuated their central projection during a cycling time trial while controlling for locomotor muscle O₂ delivery. With no difference in leg O₂ delivery, afferent blockade attenuated the centrally mediated restriction in motoneuronal output and improved cycling performance.

[Association of CYP19A1 gene rs7176005 single nucleotide polymorphism with breast cancer risk and clinicopathologic features of tumor]

Objective: The aim of this study was to investigate the association of the CYP19A1 rs7176005 single nucleotide polymorphism (SNP) with breast cancer risk and with clinicopathologic features of tumors. Methods: This study was conducted by including 138 patients with breast cancer (cancer group), those who diagnosed as primary breast cancer after operation by pathology. There were 293 cases in the group of benign breast disease which was presented as a solid mass by the color ultrasound and pathologically diagnosed as "fibroadenoma or adenosis" (benign breast disease group), the cases were paired with breast cancer patients by age±5 in the same period, and there were 259 cases in the group of healthy control who received routine physical examination during the same period and were paired with breast cancer patients by age±5 without any detection of breast related diseases (healthy control group) at West China hospital between September 2012 and November 2016. The CYP19A1 rs7176005 SNP was detected by a direct sequencing method. Hardy-Weinberg test was used to analyze the genetic balance of the 3 groups. Chi square test was used to compare the distribution of rs7176005 genotypes between the 3 groups, and the differences of clinicopathological features in breast cancer patients carrying different genotypes. Results: The ages of the breast cancer cases, the benign breast disease group and the healthy control group were (44.69±8.09), (42.33±11.44) and (41.92±9.61) years old, respectively. Hardy-Weinberg equilibrium test identified that the composition ratios of alleles C and T in breast cancer group, benign breast disease group and healthy group were not statistically significant (χ(2) values were 0.83, 0.34 and 0.04, respectively, P values were 0.363, 0.561, and 0.852, respectively). All the three groups met the genetic balance, had consistency and could represent the population. Among the 138 cases of breast cancer, the CYP19A1 rs7176005 SNP was significantly associated with the diameter of the tumor (P=0.031). The majority of tumor size was <2 cm in patients who carrying TT and CT genotypes, and the proportion was 75% (12/16) and 58% (40/69), respectively. While those patients with TT genotype were mainly >2 cm and ≤5 cm, and the proportion was 51% (27/53). The distribution of TNM stage among patients with different genotypes was also statistically significant (χ(2)=11.19, P=0.025). The most common stage was Ⅱ in Patients who carrying CC and CT genotypes, and the proportion was 45.3% (24/53) and 52.2% (36/69), respectively. While those patients with TT genotype was mainly in stage Ⅰ and the proportion was 56.3% (9/16). Conclusion: Though the CYP19A1 rs7176005 SNP is not associated with breast cancer development, breast cancer patients with the C allele exhibit a high tumor growth rate and large diameters.

Acute modulation in dietary behavior following glycogen depletion and postexercise supplementation in trained cyclists

We investigated the influence of immediate postexercise dietary supplementation on the subsequent food consumption pattern and endurance exercise performance in physically trained individuals. On 2 occasions, trained male cyclists performed a glycogen-depleting exercise bout followed by a 2-h nutritional supplementation period, 28 h of free-living recovery, and a subsequent 40-km cycling time trial. During the 2-h postexercise supplementation, the subjects consumed equal volumes of reduced-fat chocolate milk (CM) or a sports beverage (SB) in a single-blind, randomized design. Thereafter, the cyclists maintained a food log during the free-living recovery period. Dietary and exercise performance parameters were compared between the treatment beverage visits. No differences in total caloric and macronutrient intakes were detected between the CM and SB trials over the course of the free-living recovery. However, a significant interaction (treatment × time) was detected for caloric and macronutrient intakes during the early phase of free-living recovery, such that significantly larger proportions were consumed shortly after SB as compared with CM. No difference was observed in completion time of the 40-km cycling time trial (CM: 66.9 ± 4.1 vs SB: 66.9 ± 3.7 min). Hence, the cyclists achieved similar levels of recovery during the prolonged, free-living period despite the different acute, postexercise nutrient intake rates. We suggest that given adequate time, athletes appear to subconsciously modify their food consumption in response to varied postexercise supplementation such that subsequent-day exercise performance is equivalent.

[The relationship between smoking status and epidermiology of asthma in people aged over 14 years in China]

Objective: To study the relationship between bronchial asthma and smoking status in Chinese people. Methods: Asthma epidemiological survey and stratified-cluster-random method survey were performed in residents over 14 years in 8 provinces (cities) of China from February 2010 to August 2012. Asthma was diagnosed based upon case history, clinical signs and lung function test. Smoking status was investigated by questionnaire. Results: Sampling population was 180 099 and 164 215 were valid. A total of 2 034 subjects were diagnosed as asthma including 79 692 men and 84 523 women. The overall prevalence rate of asthma was 1.24% (2 034/164 215). Smokers were 23.8% (39 137/164 215) in the whole population. Smokers were 34.5% (702/2 034) in asthmatic patients, compared with 23.7% (38 435/162 181) in no-asthmatic population. The incidence of asthma was 1.79% and 1.06% in smokers and non-smokers respectively (P<0.001), suggesting that OR of smoking was 1.70 (95% CI 1.55-1.86, P<0.001). According to asthma control test (ACT) score, the level of asthma control in non smoking group was higher than that in smoking group(43.2% vs 35.3%). The times of hospitalization due to acute exacerbations(0.51 vs 0.41 events/person/year), total hospitalization rate(27.35% vs 20.12%), annual emergency room visits (0.80 vs 0.60 events/person/year) and emergency room visit rate (31.77% vs 24.47%) were all much higher in smoking asthmatic patients than those in non smoking asthmatic patients, indicating that the level of asthma control in smoking patients was significantly worse than in non smoking patients. Conclusions: The smoking rate in Chinese people over 14 years is still high. The prevalence rate of asthma in smokers is significantly higher than that of non-smokers. The level of asthma control in smokers is significantly worse than that in non smokers.

[Chinese expert consensus for non-antiinfective effects and clinical use of macrolides]

Important/potential value of macrolides has been proved in the management of chronic respiratory diseases by increasing basic and clinical trials.Through three face-to-face discussions, 10 experts examined important data and drafted this consensus related to macrolides: (1) mechanism of non-antiinfective effects; (2) clinical use in chronic respiratory diseases; (3) cautions of long-term use.The mechanism out of non-antiinfective effects includes anti-inflammatory effect, modifying airway secretion, immune-regulation related to antibacterial effect, corticoid saving effect and anti-viral effect.The efficacy of long-term use of low-dose macrolides is definitely confirmed in diffuse panbronchiolitis, chronic rhinosinusitis. It is considerably used in bronchiectasia, cystic fibrosis, severe asthma and chronic obstructive pulmonary disease. Further studies should be conducted in cryptogenic organizing pneumonia and respiratory viral infection. It should be paid attention to its possible adverse effects (including drug interactions, cardiac toxicity, ototoxicity and disturbance of intestinal flora) and drug resistance in long-term use.A Chinese consensus for non-antiinfective effects and clinical use of macrolides is developed for the first time, which aims to expand their rational use and the further research.

[A cross-section study of severe asthma in eight provinces of China]

Objective: To analyze the prevalence of severe asthmain China. Methods: The epidemiological data was collected from 2 034 asthmatics who were diagnosed in the last epidemiological survey from 2009 to 2010 in 8 provinces. Results: According to the questionnaire survey, among the 2 034 patients, the previously diagnosed patients accounted for 72.47% (1 474/2 034) and the percentage of newly-diagnosed patients was 27.53% (560/2 034). In those 1 474 previously diagnosed asthmatics, 122 (8.28%) were classified into severe asthma, while 6.00% (122/2 034) of all asthmatics and 0.07% (122/164 215) of total respondents presented as severe cases. Statistically, there was no difference in the prevalence of severe patients between men and women. The morbidity rate of severe asthma was the lowest in the 21-30 year old group and the highest in 61-70 year old group (0.85% and 8.31% respectively). The difference among ages was statistically significant (χ²=18.791, P=0.005). In addition, the prevalence rates of severe asthma were also significantly diverged among patients with different education background(χ²=24.639, P<0.000 1). A negative relation was found between education level and the proportion of severe cases. Moreover, the morbidity of severe asthma in smoking patients and non-smoking patients were significantly different as well (χ²=7.447, P<0.05). Compared with asthma patients who do not smoke, smokers were more likely to suffer severe asthma (OR=1.663, 95% CI 1.150-2.404). Conclusions: The prevalence rate of severe asthma in China is similar to that in other countries.Elderly patients have higher risk of severe asthma. Smoking is considered as a risk factor for severe asthma.

Immunotolerant indoleamine-2,3-dioxygenase is increased in condyloma acuminata

BACKGROUND

The tryptophan-depleting enzyme indoleamine-2,3-dioxygenase (IDO) is critical for the regulation of immunotolerance and plays an important role in immune-associated skin diseases.

OBJECTIVES

To analyse the level of IDO in condyloma acuminata (CA) and its role in this condition.

METHODS

IDO expression was assessed in the skin and peripheral blood of healthy controls and patients with CA. To assess the role of skin IDO in immunity, the ability of isolated epidermal cells to metabolize tryptophan and the influence on polyclonal T-cell mitogen (PHA)-stimulated T-cell proliferation were explored.

RESULTS

IDO median fluorescence intensities in peripheral blood mononuclear cells from patients with CA were similar to those from healthy controls. Immunohistochemistry showed that IDO⁺ cells were rare in normal skin and the control skin of patients with CA, but were greatly accumulated in wart tissue. Most fluorescence signals of IDO⁺ cells did not overlap with those of CD1a⁺ Langerhans cells. Human papillomavirus (HPV) DNA probe in situ hybridization showed a large number of IDO⁺ cells in the HPV^- site. Keratinocytes in the skin of healthy controls and the circumcised skin of patients with CA could minimally transform tryptophan into kynurenine, but IDO-competent epidermal cells from warts could transform tryptophan. In addition, these IDO-competent epidermal cells could inhibit PHA-stimulated T-cell proliferation. The addition of an IDO inhibitor, 1-methyl-d-tryptophan, restored the inhibited T-cell proliferation.

CONCLUSIONS

Abnormally localized high IDO expression might be involved in the formation of a local immunotolerant microenvironment.

[Gene typing and antibiotic resistance of methicillin-resistant Staphylococcus aureus isolated from lower respiratory tract at two hospitals in Shanghai]

OBJECTIVE

To study the genotyping characteristics and antibiotic resistance of methicillin-resistant Staphylococcus aureus(MRSA) isolated from lower respiratory tract at 2 different level hospitals in Shanghai.

METHODS

The subjects included 155 patients at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014, including 108 males and 47 females, with a mean age of 67.8±16.5. The 155 MRSA strains were isolated from lower respiratory tract specimens and multilocus sequence typing (MLST) and spa typing were analyzed by the PCR method. The antimicrobial resistance of MRSA was tested by VITEK-32. Fisher's exact test was used for statistical analysis.

RESULTS

Among the 155 strains, 28 MLST-spa molecular types were identified, of which ST764-t002(41.29%), ST239-t037(17.42%) and ST239-t030(10.32%) were the most predominant types. The MRSA strains were susceptible to linezolid, vancomycin and teicoplanin, and also had a lower resistance to trimethoprim-sulfamethoxazole and rifampin, with a susceptible rate of 83.9% and 83.2% respectively, but were highly resistant to other antibiotics. The resistance rate of ST239-t037 to trimethoprim-sulfamethoxazole was higher than that of other types, and the resistance rate of ST239-t030 to rifampin was higher than that of other types, the differences being significant(P<0.001). The mean length of hospital stay of the 155 patients was (97±84) days, and mechanical ventilation were used in 78(50.3%) patients, while 108(69.7%))patients received invasive procedures. Broad-spectrum antibiotics were used in 136 (87.1%) patients. There were differences in age, hospitalization days, smoking history, history of COPD, mechanical ventilation, and operation between the 2 hospitals(P<0.05).

CONCLUSION

Most of the MRSA strains at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014 were multi-drug resistant, and the susceptibility spectrum of different genotypes was different.

Obvious emphysema on computed tomography during an acute exacerbation of chronic obstructive pulmonary disease predicts a poor prognosis

BACKGROUND

Emphysematous change on computed tomography (CT) during the stable phase of chronic obstructive pulmonary disease (COPD) is reported to correlate with COPD prognosis. Acute exacerbation of COPD (AECOPD) is associated with a high risk of mortality and a poor prognosis.

AIMS

This study aims to study the relationship between prognosis and emphysematous changes on CT during an AECOPD.

METHODS

Histories were recorded, and CT acquired for 106 patients who visited the emergency department for an AECOPD. Emphysematous change was quantified by measuring the percentage of low-attenuation areas (LAA%) in the entire lung on CT images with a threshold of -950 Hounsfield units. Other factors that could influence AECOPD prognosis were also recorded on admission and analysed. At follow ups conducted in 1 year, patient survival, the modified Medical Research Council (mMRC) Dyspnoea Scale, and performance status (PS) were evaluated, and a COPD Assessment Test (CAT) was completed.

RESULTS

The 1-year follow up was completed by 103 of 106 patients. The median LAA% was significantly higher in non-survivors (11%, n = 16) than in survivors (5.69%, n = 87) (P = 0.006) at the 1-year follow up. LAA% was significantly correlated with mMRC grade (r = 0.285, P = 0.008), PS (r = 0.397, P < 0.001) and CAT score (r = 0.27, P = 0.017) at the 3-month follow up, and with mMRC grade (r = 0.405, P < 0.001) and PS (r = 0.377, P < 0.001) at the 1-year follow up. LAA% > 7.5% was a significant predictor of 1-year mortality, higher mMRC and PS at the 3-month and 1-year follow ups, after adjustment for other prognostic predictors.

CONCLUSION

Obvious emphysematous changes on CT (LAA% > 7.5%) during an AECOPD predicts a poor prognosis independent of other known indicators.

Hypoxia induces dysregulation of local renin-angiotensin system in mouse Lewis lung carcinoma cells

The renin-angiotensin system (RAS) influences cancer biology and is frequently dysregulated in malignancy. However, regulation of tumor local RAS remains poorly understood. Hypoxia is a hallmark of solid tumors and affects nearly every major aspect of cancer biology. Previous studies have shown that hypoxia can regulate RAS expression in somatic tissues and cells. The aim of this study was to investigate the influence of hypoxia on local RAS expression in mouse Lewis lung carcinoma (LLC) cells. For hypoxia treatment, LLC cells were cultured in a hypoxia incubator or treated with hypoxia-mimetic cobalt chloride. Hypoxia up-regulated angiotensin II, angiotensin-converting enzyme (ACE), and angiotensin II type 1 receptor (AT1R), and down-regulated ACE2 and angiotensin II type 2 receptor in LLC cells. Captopril, an ACE inhibitor, and losartan, an AT1R blocker, decreased expression of ACE and AT1R, but increased expression of ACE2 and angiotensin II type 2 receptor in LLC cells under hypoxia. Captopril and losartan also suppressed vascular endothelial growth factor-A expression in LLC cells under hypoxia. These findings suggest that hypoxia induces dysregulation of local RAS in LLC cells. The pathophysiological importance of hypoxia-induced RAS dysregulation and potentially therapeutic effects of RAS inhibitors on hypoxic tumor cells should be further examined.

Meta-analysis demonstrates lack of association between the ACE gene I/D polymorphism and obstructive sleep apnea-hypopnea syndrome occurrence and severity

Published data on a possible association between the angiotensin-converting enzyme (ACE) gene I/D polymorphism and obstructive sleep apnea-hypopnea syndrome (OSAHS) occurrence and its severity risk are inconclusive. We performed a meta-analysis of case-control studies published in English or Chinese. Thirteen studies, totaling 1361 cases and 1373 controls, were investigated for association of the ACE I/D polymorphism with OSAHS. We also made a study of ACE I/D with OSAHS severity risk, including 879 mild/moderate OSAHS patients and 357 severe OSAHS patients. A random-effects model was used, irrespective of between-study heterogeneity. Study quality was assessed in duplicate. Overall, the ACE I/D polymorphism was not significantly associated with an increase in OSAHS risk [odds ratio (OR) = 1.21; 95% confidence interval (95%CI) = 0.88-1.65; P = 0.24]. In subgroup analysis by ethnicity, comparison of alleles I with D demonstrated a 58% (nonsignificantly) increased risk for OSAHS in Chinese (OR = 1.58; 95%CI = 0.92-2.70; P = 0.09). We also found that there was no significant association between ACE I/D and OSAHS severity risk. No publication biases were observed. This meta-analysis suggests that there is no significantly increased risk for OSAHS occurrence or severity associated with the ACE I/D polymorphism.

[Preventive effect of cardiomyopeptidin on rat heart injured by ischemia-reperfusion]

OBJECTIVE

To investigate the preventive effect of cardiomyopeptidin of small molecular weight polypeptide on rat hearts injured by ischemia-reperfusion.

METHODS

In a rat model injured by ischemia-reperfusion in the heart, observation was made on the influence of cardiomyopeptidin on the activities of creatine kinase (CK) and lactate dehydrogenase(LDH), as well as on the content of MDA in plasma after the preventive drug was used.

RESULTS

Cardiomyopeptidin could obviously prevent the injury caused by ischemia-reperfusion, reduce the activities of CK and LDH and the content of MDA in a dose-dependent manner.

CONCLUSION

Cardiomyopeptidin has a preventive effect on myocardium injured by ischemia-reperfusion and this may be related to its reducing the release of myocardial enzyme and anti-lipoperoxidation.

Coexisting sharp ductal angulation with intrahepatic biliary strictures in right hepatolithiasis

OBJECTIVE

To investigate the clinical characteristics of a coexisting sharp ductal angulation (< 90 degrees) with biliary stricture and to evaluate the difficulties it imposes in the management of retained or recurrent hepatolithiasis.

DESIGN

Case-controlled study.

SETTING

A referral center.

PATIENTS

Eighteen consecutive patients having right-sided hepatolithiasis and a coexisting sharp ductal angulation associated with biliary stricture (group 1) were compared with 84 patients matched with sex, age, and conditions of hepatolithiasis and intrahepatic biliary stricture(s) but no sharp angulated duct (group 2).

INTERVENTION

Postoperative cholangioscopic management (electrohydraulic lithotripsy or other lithotripsy, lithotomy, balloon dilation, biopsy, etc, via T-tube tract or percutaneous transhepatic route).

MAIN OUTCOME MEASURES

Sessions of manipulations, incidence of complications associated with interventions or disease, and mortality were compared.

RESULTS

Patients of group 1 needed more sessions of postoperative manipulation of stones and strictures (13.7 +/- 4.2 vs 8.0 +/- 2.3; P < .001). During management, there was a significantly increased vulnerability of severe and/or recurrent cholangitis (66.7% vs 9.5%; P < .001), septic shock (77.8% vs 11.9%; P < .001), liver abscess (55.6% vs 7.1%; P < .001), or massive hemobilia (33.3% vs 7.4%) in group 1 than in group 2. Their risks of coexisting secondary biliary cirrhosis (55.6% vs 9.5%; P < .001) and/or cholangiocarcinoma (16.6% vs 2.4%; P < .04) and mortality (27.8% vs 4.8%; P < .01) were also significantly higher in group 1.

CONCLUSION

Our results suggest that the coexisting sharp ductal angulation with biliary strictures in right-sided hepatolithiasis is a distinct difficult clinical entity in the field of biliary tract calculi.

[Lung biopsies with light microscopic and ultrastructural observations in 34 cases of diffuse pulmonary diseases]

Lung biopsies with light microscopic and ultrastructural observations were performed in 34 cases of diffuse pulmonary diseases. Open lung biopsy 2 cases, transfiberoptic bronchoscopy lung biopsy 32 cases. There were 19 (56%) idiopathic interstitial fibrosis, 3 (9%) pulmonary alveolar proteinosis, 3 (9%) pulmonary sarcoidosis, 1 (3%) idiopathic pulmonary hemosiderosis, 2 (6%) pulmonary mycosis, 1 (3%) alveolar cell carcinoma, 2 (6%) pulmonary tuberculosis and 3 (9%) pulmonary collagen diseases. Diagnosis was based on clinical data and pathologic manifestation. Lung biopsy with light and electronic microscopic examination is useful in etiologic diagnosis and differential diagnosis for diffuse pulmonary diseases.

New insights into the regulation of megakaryocytopoiesis by haematopoietic and fibroblastic growth factors and transforming growth factor beta 1

Effects of cytokines on murine megakaryocyte (MK) colony formation from either unfractionated marrow cells or purified early haematopoietic cells were studied. Recombinant interleukin-3 (IL3), interleukin-6 (IL6), granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin (Epo) and acidic and basic fibroblast growth factor (aFGF and bFGF) each was able to stimulate MK colony growth although they varied somewhat in their potential. IL6 and FGFs, in addition to their effect on MK colony growth, increased the size of individual MK. The combination of IL3 with IL6 or FGF resulted in an additive action. Monoclonal anti-IL6 antibody completely neutralized the activity of mouse IL6 and FGFs but had no effect on human IL6, mouse IL3 and GM-CSF. When using purified lineage negative marrow cells, only IL3 and IL6 promoted MK colony formation. Transforming growth factor beta 1 (TGF-beta 1) at 10-200 pg/ml selectively inhibited IL3-induced MK colony formation, and at 0.2-0.5 ng/ml it still had no obvious effect on the activity of IL6 or GM-CSF but caused an inhibition of FGF-induced MK colony formation. These data suggest that differential mechanisms are involved in the regulation of megakaryocytopoiesis by IL3, IL6, FGFs and GM-CSF, and that TGF-beta 1 negatively regulates MK development mainly by interfering with the action of IL3.

Studies on monoclonal antibodies against human platelets--a monoclonal antibody to human platelet glycoprotein I--SZ-2

A monoclonal antibody, SZ-2, reacts specifically on human platelets and megakaryocytes. The platelets from 10 normal donors are bound to 15,200 +/- 4,100 SZ-2 molecules/platelet. The antigen recognized by SZ-2 is chymotrypsin-sensitive but neuraminidase-insensitive, and has been identified as glycoprotein Ib (GPIb) by an affinity chromatography technique. SZ-2 is different from other monoclonal antibodies to GPIb. It inhibits not only platelet aggregation induced by ristocetin, but also platelet aggregation induced by collagen (type I) and by PAF. SZ-2 also inhibits platelet serotonin and beta-thromboglobulin release in response to these stimuli.