Sonographic analysis of rat submandibular glands in experimentally-induced sialadenitis

OBJECTIVES: To correlate the sonographic features of experimentally-induced obstructive sialadenitis in rat submandibular glands with the histopathological changes. MATERIALS AND METHODS: Changes in sonograms of ligated and non-ligated rat submandibular glands were compared with the wet weight and histopathology. Sonograms were obtained at 1, 2, 3, 4, 5, 7 and 21 days after duct ligation at 13 and 14 MHz for B-mode and for power Doppler mode respectively. Changes in gland size, echo intensity, distribution of internal echoes and vascularity were evaluated both qualitatively and quantitatively. RESULTS: Changes in size of the ligated glands were very similar to changes in wet weight. The ligated glands showed lower echo intensity than the non-ligated glands. The ligated glands showed higher echo intensity in the central portion at 4-7 days after duct ligation which resulted in heterogeneity of the glands. Vascularity of the ligated glands increased in the acute phase, and then decreased to the level of the non-ligated glands. CONCLUSIONS: The three phases in the changes in ligated glands identifiable histopathologically can be differentiated by B-mode sonography. Power Doppler can differentiate the acute phase. Sonography therefore appears useful for the diagnosis of the degree of gland damage.     

Magnetic resonance imaging of experimentally-induced sialadenitis in rat submandibular glands

OBJECTIVES: To correlate the features of magnetic resonance (MR) images of experimentally induced obstructive sialadenitis in rat submandibular glands with the histopathological changes. METHODS: Changes in MR images of ligated and non-ligated rat submandibular glands were compared with the histopathological changes and wet weight ratios. Spin echo T1 weighted images (SE T1WI), fast spin echo T2 weighted images (FSE T2WI), and gradient echo T2 weighted images (GE T2WI) were obtained at 1, 2, 3, 4, 5, 7 and 21 days after duct ligation with a 0.3 T MR imaging system. RESULTS: There was a significant difference (P<0.05) between the signal intensity ratios of both ligated and non-ligated glands on each day, except at 21 days on GE T2WI. On SE T1WI, small interval changes of signal intensity ratios were observed on both glands, whereas there were large interval changes at 1 - 2 days, 4 - 7 days and 21 days after duct ligation with FSE T2WI. These three periods correlated highly with three phases of histopathological changes, swelling of acinar cells at 1 - 2 days, atrophy of acinar cells and increase of duct-like structures at 3 - 7 days, and proliferation of connective tissue at 21 days, and the changes in wet weight ratios. A similar tendency was observed on GE T2WI to FSE T2WI. CONCLUSIONS: As FSE T2WI showed large changes in signal intensity that correlated highly with histopathological three phases, it is recommended as the MR sequence of choice for diagnosing the degree of damage in obstructive sialadenitis.     

Voluntary training in mice and submandibular lymphocyte response to acute exercise

INTRODUCTION: Submandibular lymph nodes (SLN) are important for immune responses to antigens in the eye and oral mucosa. Athletes and exercise participants may be at increased risk of ocular, oral, and upper respiratory tract infections. PURPOSE: This study was conducted to examine the effects of voluntary training on the distribution, number, and apoptotic status of SLN lymphocytes in response to an acute bout of strenuous exercise. METHODS: Female C57BL/6 mice were assigned to voluntary wheel-running (WR) exercise (N=20) or were sedentary (N=10) for 16 wk. SLN lymphocytes were examined immediately (EX+Imm) or 24 h (EX+24 h) following strenuous treadmill exercise, or exposure to treadmill conditions without running (NonEX). Intracellular glutathione (GSH), mitochondrial membrane potential (MMP), cell viability (propidium iodide uptake, PI), surface phosphatidylserine (Annexin V), T-lymphocyte (CD3, CD4, CD8), and B-lymphocyte (CD19) phenotype distribution and number were assessed. RESULTS: The WR mice had a higher number and percent CD8 SLN lymphocytes, higher MMP, and lower Annexin V/PI SLN lymphocytes than controls. Regardless of training status, an acute bout of strenuous exercise decreased the total and phenotype specific (CD3, CD4, CD8) number of cells, MMP, and GSH levels immediately after exercise. CONCLUSION: WR in mice improved some aspects of cell viability in SLN lymphocytes compared with controls, but did not prevent the transient cell loss after acute treadmill exercise. Given the depletion in intracellular GSH levels, oxidative stress may account for the decline in SLN lymphocyte numbers following acute exercise. Loss of SLN lymphocytes may have consequences for ocular, oral, and upper respiratory tract health in some exercise participants and athletes during periods of overtraining.     

Computed tomography of the submandibular salivary glands

Computed tomography offers a convenient method for the evaluation of the submandibular salivary glands and their surroundings. Normal measurements were established based on 38 normal subjects. The visualization of the ductal system in the gland and the relationship of the gland to the platysma muscle were recorded. The CT scans of 12 patients with a tongue base carcinoma and 4 patients with a verified obstruction of the submandibular duct were also reviewed to establish how the glands are affected by extrinsic lesions. The normal glands measured 28 x 18 mm (+/- 5 mm) in the axial plane. Two patients with unilateral hypoplasia of the gland were found in the normal group. Visualization of the intraglandular duct is not a specific finding since it was observed in more than 25 per cent of the normal group. Displacement and bulging of the platysma muscle by the submandibular gland can be a sign of glandular enlargement. It was also seen in 9 out of 12 patients with carcinoma of the base of the tongue.     

Meal-induced thermogenesis following exercise training in the rat

The effects of treadmill exercise on the thermic effect of a meal were studied in male Sprague-Dawley rats (370 to 400 g, 4 to 5 months of age). Rats were exercised for 60 min, 5 d.wk-1 for 8 to 10 wk, at a speed of 27 m.min-1 and with a grade of 8%. Sedentary (N = 9) and exercised (N = 8) rats were given food and water ad libitum. Oxygen consumption was measured at rest and following the ingestion of a meal consisting of 81% carbohydrate, 9% protein, and 10% fat (by calories). In those animals that were exercised, oxygen consumption measurements were performed 24 h after the completion of an exercise bout. Although all animals gained weight during the experimental period, the exercised group gained significantly less than did the sedentary rats. Resting oxygen consumption [ml/(min X g body mass.67)] was not significantly different between the exercised and sedentary rats. The ingestion of the high carbohydrate meal significantly increased mass-independent oxygen consumption above resting values in both groups; the values for the exercised rats were greater than those for the sedentary rats. However, there were no differences between the exercised and sedentary rats in meal-induced oxygen consumption when the data were expressed as a function of lean body mass [ml/(min X g lean body mass)] or as mass-independent lean body mass [ml/(min X g lean body mass.67)]. These data suggest that exercise-trained rats have increased diet-induced thermogenesis and may be one factor in the loss of weight sometimes found in response to exercise.     

Effects of exercise training on plasminogen activator inhibitor activity.

Plasminogen activator inhibitor (PAI) activity, an important regulator within the fibrinolytic system, has been shown to be a risk indicator for venous and arterial thrombosis. The present study aimed to test the effects of exercise training on PAI activity, and to link possible changes in PAI activity to changes in cardiovascular fitness, body composition, and the lipid profile. Four groups of previously sedentary subjects were studied thrice in an 8-month period. A long-term training group (N = 11) trained during the entire 8-month period. A detraining group (N = 14) trained for 4 months and then reverted to sedentary habits. A postponed training group (N = 16) trained only during the second 4-month period, and a no-training control group (N = 9) remained untrained throughout the entire 8-month period. PAI activity always decreased in response to training, but the training effects were small and spontaneous seasonal shifts in PAI activity of the control groups clouded their interpretation. Furthermore, detraining failed to influence PAI activity and training-induced changes in PAI activity were not related to simultaneous changes in maximal oxygen consumption, diastolic blood pressure, triglycerides, or percentage body fat, and inconsistently related to the training-induced changes in LDL-cholesterol and HDL-cholesterol. The occurrence of simultaneous changes in body fat, blood pressure, and the lipid profile underscores the potential of regular exercise to protect against cardiovascular disease. Whether these beneficial effects are accompanied by changes in the fibrinolytic system remains to be proven.     

Effects of short-term training on cardiac function during prolonged exercise

To determine the relationship between the training-induced increases in plasma volume (PV) and alterations in cardiac performance during prolonged submaximal cycle exercise, seven male subjects were studied prior to and following a short-term (3 d) training period (2 h.d-1 at 65% VO2max). Mean (range) VO2max was 3.42 l.min-1 (2.96-3.87). Training resulted in a 20% increase (P less than 0.05) in plasma volume (PV) and a 12% increase (P less than 0.05) in total blood volume (TBV). In contrast, training had no effect (P greater than 0.05) in altering exercise VO2, VCO2, VE BTPS, or RER. Cardiac output (Q) was higher (P less than 0.05) posttraining at all exercise sampling times (30, 60, 90, and 120 min). The elevations in Q were accompanied by an average decrease (P less than 0.05) in stroke volume (SV) of 22 ml. Arteriovenous O2 (a-v O2) difference was depressed (P less than 0.05) during exercise following the training. Although elevations (P less than 0.05) in core temperature (degrees C) occurred during the exercise, the training-induced PV increases did not affect thermoregulatory behavior. These results indicate that an early adaptive response to exercise training is an elevation in Q, an increase in SV, and a reduction in HR. These effects persist during prolonged exercise in spite of the progressive increase in body heat content. It is proposed that the increase in Q serves primarily to increase muscle blood flow and maintain arterial O2 delivery, while the altered cardiodynamic behavior serves to increase cardiac reserve, providing a greater tolerance to prolonged heavy exercise.     

Effects of chronic intense exercise training on the leukocyte response to acute exercise.

Circulatory leukocytes vary significantly in response to acute bouts of exercise. However, little is known concerning the adaptability of this response to chronic intense exercise training. We investigated the circulating leukocytic response to acute exercise in trained athletes during a 28-day intense exercise training program. On day 0, 14, 28 and two days after cessation of the increased training, eight trained male athletes (VO2max greater than 60 ml.kg-1.min-1) were subjected to a 20-km bicycle ergometer time trial. Blood samples were drawn before (PRE, for resting baseline values) and five minutes after (POST, response to acute exercise) the time trial. Beginning on day 0, athletes were instructed to increase the duration of their training 50%. The intense exercise training, which lasted 28 days, was verified weekly. Acute bouts of exercise caused a significant increase (p less than 0.05) in circulating white blood cells, lymphocytes, polymorphonuclear neutrophils and monocytes. The baseline resting values and the magnitude of the response to the acute bouts of exercise in the above parameters were not different during the 28 days of chronic intense exercise training or 2 days after cessation of training as compared to the values observed on day 0. Similarly there was a significant increase (p less than 0.05) in cortisol levels in response to the acute bouts of exercise during the chronic intense exercise training, but the increases were not different from that observed under baseline conditions. These results lead to the conclusion that chronic intense exercise training does not alter the circulating leukocytic response to acute exercise.     

Effects of resistive training on lipoprotein-lipid profiles: a comparison to aerobic exercise training

A recent surge of cross-sectional and longitudinal studies dealing with resistive training and lipid profiles have produced conflicting results. The majority of cross-sectional studies demonstrate a reduced HDL cholesterol level or elevated total cholesterol to HDL ratio in strength trained athletes as compared with endurance trained athletes. Because of selection biases from many of these studies, there is a lack of control for factors that may influence lipids and lipoproteins, such as age, body composition, diet, and anabolic-androgenic steroid use. Most investigators have reported improved lipoprotein-lipid profiles from resistive training programs. However, many of these studies have design flaws or limitations that make their conclusions questionable. The most serious design flaws include the combination of no control group and only one blood sample taken before and after training, the use of subjects who have low risk profiles, and the lack of control for dietary effects. In a recent study in which we attempted to control for these factors, no changes in lipid profiles were observed after 20 wk of resistive training among individuals at risk for coronary heart disease (CHD). A group serving as reference controls who participated in aerobic-type exercise training during the same time period reduced their plasma triglyceride levels but did not alter their cholesterol or lipoprotein levels. No changes in any lipids or lipoproteins were observed in a group of inactive controls. Thus, resistive training does not appear to alter lipoprotein-lipid profiles among individuals at risk for CHD.     

Effects of prior concentric training on eccentric exercise induced muscle damage

BACKGROUND: Exercise induced muscle damage (EIMD) from strenuous unaccustomed eccentric exercise is well documented. So too is the observation that a prior bout of eccentric exercise reduces the severity of symptoms of EIMD. This has been attributed to an increase in sarcomeres in series. Recent studies have suggested that prior concentric training increases the susceptibility of muscle to EIMD following eccentric exercise. This has been attributed to a reduction of sarcomeres in series, which decreases muscle compliance and changes the length-tension relation of muscle contraction. OBJECTIVE: To assess the effects of prior concentric training on the severity of EIMD. METHODS: Four men and four women (mean (SD) age 21.1 (0.8) years) followed a four week concentric training programme. The elbow flexor musculature of the non-dominant arm was trained at 60% of one repetition maximum dynamic concentric strength performance, three times a week, increasing to 70% by week 3. After three days of rest, participants performed 50 maximal isokinetic eccentric contractions on both arms. All participants gave written informed consent before taking part in this study, which was approved by the school ethics committee. Strength, relaxed arm angle (RAA), arm circumference, and soreness on active extension and flexion were recorded immediately before eccentric exercise, one hour after, and at 24 hour intervals for three days. Data were analysed with fully repeated measures analyses of variance. RESULTS: Strength retention was significantly (p<0.01) greater in the control arm than the trained arm (84.0 (13.7)%, 90.4 (14.7)%, 95.2 (10.5)%, 103.5 (7.6)% v 75.5 (11.3)%, 77.6 (15.3)%, 80.1 (13.9)%, 80.9 (12.5)%) at one, 24, 48, and 72 hours respectively. Similarly, soreness was greater in the trained arm (0.7 (0.6), 3.1 (1.4), 3.0 (1.5), 1.9 (2.3)) than in the untrained arm (0 (0.2), 1.6 (1.3), 1.4 (0.6), 0.6 (0.4)) at one, 24, 48, and 72 hours respectively (p<0.05). Concentric training induced a significant reduction in RAA (165.2 (6.7) degrees v 157.3 (4.9) degrees ) before the eccentric exercise bout (p<0.01). This was further reduced and remained lower in the trained arm at all time points after the eccentric exercise (p<0.01). The arm circumference of the concentrically trained arm was significantly greater than baseline (p<0.05) at 72 hours (30.3 (2.9) v 29.8 (3.3) cm). CONCLUSIONS: These findings extend the understanding of the effects of prior concentric training in increasing the severity of EIMD to an upper limb exercise model. The inclusion of concentric conditioning in rehabilitation programmes tends to exacerbate the severity of EIMD in subsequent unaccustomed exercise. However, where concentric conditioning is indicated clinically, the net effect of conditioning outcome and EIMD may still confer enhanced strength performance and capability to dynamically stabilise a joint system.     

Effects of hyperoxic training on performance and cardiorespiratory response to exercise

PURPOSE: To determine whether training in a hyperoxic environment would result in greater increases in VO2max and performance at 90% VO2max as compared with training in normoxia. METHODS: In a single blind design nine athletes trained for 6 wk on a cycle ergometer 3 d.wk(-1), 1 h.d(-1) (10 x 4-min intervals, with 2 min of rest between intervals) at 90% HR(max). Training HR range was maintained by adjusting the power output. Subjects were randomly assigned to H (60% O2) or N (21% O2) breathing conditions for training. After 12 wk of detraining, a second 6-wk training protocol was completed with the breathing conditions reversed. VO2max, performance time at 90% VO2max and cardiorespiratory response to a steady-state exercise at 80% VO2max were measured pre- and posttraining. All pre- and posttraining tests were conducted under normoxic conditions. RESULTS: There were no significant differences between pretraining results for any of the parameters. Power output was 8.1% higher while training in H compared with N, to maintain training HR. Both H and N training resulted in increased performance time, with H being greater than N. Although there was a trend for a greater increase in VO2max after H versus N training, this difference was not significant. HR(max) did not change for H or N. HR VE at 80% VO2max decreased posttraining with no differences between H and N. CONCLUSION: The data showed that a higher power output was required to maintain HR during H training. This increased training intensity during H resulted in improved exercise performance whereas cycling at 90% VO2max in room air and may be due to peripheral factors because cardiorespiratory responses were similar.     

茶多酚拮抗放射性颌下腺细胞凋亡的实验研究

目的 探讨茶多酚(TP)对放射性颌下腺损伤的防护作用。方法 将Wistar大鼠60只随机分为照射组(R)、茶多酚+照射组(TPR),照射前14 d至标本提取当天分别予以生理盐水和茶多酚灌胃,采用⁶⁰Co γ射线15 Gy 一次性照射大鼠头颈部。照射结束后3、6和30 d,每组各取10只大鼠颌下腺,原位末端标记法(TUNEL法)检测腺体细胞和导管细胞凋亡,免疫组织化学方法检测腺体Bcl-2﹑Bax的表达,透射电镜观察组织细胞超微结构改变。结果 茶多酚可以使照射后3﹑6和30 d 的颌下腺腺泡细胞及导管细胞凋亡指数降低,与照射组相比,差异有统计学意义(F =56.383, P <0.01);Bcl-2和Bax的表达组间差异无统计学意义;电镜下TPR组损伤较轻,细胞核凋亡改变不典型。结论 茶多酚可以对放射性颌下腺损伤起到一定防护作用,其机制可能是通过拮抗细胞凋亡实现的。     

Effects of endurance training on the androgenic response to exercise in man

Six healthy subjects, aged 35.8 +/- 4.4 years, volunteered to participate in a 40-week training program on a bicycle ergometer [three 60-min sessions per week at 80%-85% of maximal oxygen uptake (VO2 max)]. Before training and at the 10th, 20th, 30th, and 40th weeks of the training program, plasma testosterone, cortisol, and androstenedione concentrations were measured at rest (t0) and at the end (t60) of a 1-h endurance exercise requiring 85%-90% of VO2 max. Training resulted in significant increases of anaerobic threshold (12.6%) and VO2 max (7.3%). The training program did not significantly alter the resting values of plasma testosterone, androstenedione, and cortisol; in contrast, the exercise responses (delta = t60-t0) of testosterone, androstenedione, and cortisol were increased. The highest amplitude of these responses was reached at the 30th week for cortisol and androstenedione and at the 40th for testosterone. These results suggest that long-term training enhances both testicular adrenal and responses to endurance exercise. The possible role of hormonal changes in the mobilization of energy substrates during exercise is discussed.     

Effects of exercise training on the menstrual cycle: existence and mechanisms

This review evaluates the status of the evidence that exercise training affects the menstrual cycle beginning with evidence for the existence of delayed menarche, amenorrhea, and luteal suppression in athletes. A later age of menarche and a higher prevalence of amenorrhea and luteal suppression have been observed in athletes, but there is no experimental evidence that athletic training delays menarche, and alternative sociological and statistical explanations for delayed menarche have been offered. Cross-sectional studies of amenorrheic athletes have revealed abnormal reproductive hormone patterns, suggesting that the GnRH pulse generator in the hypothalamus is failing to initiate normal hypothalamic-pituitary-ovarian function. Longitudinal data show that the abrupt initiation of a high volume of aerobic training can disrupt the menstrual cycle in at least some women, but these women may be more susceptible to reproductive disruption than others, and some aspect of athletic training other than exercise (such as caloric deficiency) may be responsible for the observed disruption. Luteal suppression may be an intermediate condition between menstrual regularity and amenorrhea in athletes, or it may be the endpoint of a successful acclimation to exercise training. A potential endocrine mechanism of menstrual disruption in athletes involving the hypothalamic-pituitary-adrenal axis is discussed. Finally, promising future directions for research on this topic are described.     

Effects of training at simulated high altitude on exercise at sea level

Nine healthy men trained one leg under normobaric (N) conditions (N-leg), the other leg under hypobaric (H; 572 mmHg) conditions (H-leg) each one 30 min, 3–4 times per week for 4 weeks at 65% of the one-legged maximal work load that could be performed for 2 min ( W _max). They performed one-legged exercise tests to fatigue before and after the training period under N conditions at a load corresponding to 80% of one-legged W _max. Muscle biopsies were taken before training from one leg and after training both from the N-leg and the H-leg at rest and after 15-min exercise and analysed for high-energy phosphates and glycogen and their degradation products. Training under N as well as under H conditions improved local energy balance in the leg (less lactate and inosine monophosphate accumulation). However, a discrepancy was found between the previously demonstrated greater increase in local oxidative potential in the H-leg than in the N-leg and the local energy balance during submaximal exercise, which improved less in the H-leg than in the N-leg (lower energy charge and higher adenosine monophosphate content). Despite less improved local energy balance after 15 min of exercise, the time to fatigue was somewhat longer in the H-leg.     

运动训练诱导自发性高血压大鼠生理性心脏肥大

 目的 观察规律运动训练对自发性高血压大鼠(SHR)心脏肥大的影响,探讨运动发挥心脏保护效应的可能机制。方法 30只SHR随机分为高血压运动组(SHR-Ex)和高血压对照组(SHR-C),15只健康Wistar大鼠作为正常血压对照组(NC)。SHR-Ex组大鼠进行8周游泳运动(每天60 min,5 d/周),SHR-C组和NC组在鼠笼内安静饲养。实验后,利用智能无创血压测试仪测量尾动脉血压,超声心动图监测心脏结构与功能,分离左心室并称重,HE和Masson染色分别获取心肌细胞横截面积(CSA)和胶原容积分数(CVF),Western Blot检测胚胎基因和心脏肥大信号途径蛋白表达量。结果 实验过程中,由于拒跑、死亡等原因共剔除7只大鼠,最终纳入38只,其中NC组15只、SHR-C组12只和SHR-Ex组11只。与NC组比较,SHR-C组大鼠出现向心性心脏肥大,心肌纤维化(CVF升高,P<0.05),心钠素(ANF)、肌球蛋白轻链-2(MLC-2)、钙调神经磷酸酶Aβ亚基(CNAβ)、PI3激酶p110α亚基[PI3-K(p110α)]和磷酸化Akt(p-Akt)蛋白表达量上调(P<0.05);与SHR-C组比较,SHR-Ex组发生离心性心脏肥大,心肌纤维化减轻(CVF下降,P<0.05),心功能增强(P<0.05),ANF、MLC-2和CNAβ蛋白表达量下调(P<0.05),PI3-K(p110α)和p-Akt的变化无统计学意义。结论 长期运动训练能够促进SHR由病理性心脏肥大向生理性心脏肥大转变,其机制可能与钙调神经磷酸酶信号途径活性下降有关。     

Effects of exercise training on cardiovagal and sympathetic responses to Valsalva's maneuver

PURPOSE: We tested the hypothesis that a strictly-controlled program of aerobic conditioning would increase vagal and decrease sympathetic responses to Valsalva straining. METHODS: Eleven young men performed a maximal aerobic capacity test, controlled frequency breathing (0.25 Hz), and three Valsalva maneuvers before and after 4 wk of exercise training on a cycle ergometer (30 min at > or = 70% max heart rate, 3 sessions. week-1). During controlled breathing and Valsalva straining, we recorded the electrocardiogram, noninvasive beat-by-beat arterial pressure, and peroneal nerve muscle sympathetic traffic at the popliteal fossa (pre- and postexercise sympathetic recordings were obtainable in 7 of 11 subjects). Vagal-cardiac tone was estimated from R-R interval standard deviations during controlled frequency breathing. Cardiovagal baroreflex sensitivity was derived from increases of R-R intervals as functions of increases in systolic pressures with linear regression analysis during phase IV pressure increases, and sympathetic sensitivity was derived from the quotient of total muscle sympathetic nerve activity and diastolic pressure changes during phase II pressure reductions. RESULTS: Exercise training increased VO2 max (3.38 +/- 0.10 pre-, and 3.64 +/- 0.11 L. min-1 postexercise; mean +/- SE; P = 0.04), R-R interval standard deviations (75 +/- 0.12 pre- and 94 +/- 0.14 ms postexercise; mean +/- SE; P = 0.03), and cardiovagal baroreflex sensitivity (15.0 +/- 1.1 pre-, and 25.0 ms. mm Hg-1 +/- 4.0 postexercise; mean +/- SE; P = 0.03). Exercise training did not change baseline sympathetic traffic (P = 0.31) or sympathetic nerve responses to diastolic pressure reductions (P = 0.12). CONCLUSIONS: Exercise training affects vagal and sympathetic mechanisms differently: cardiovagal baroreflex sensitivity is increased, but sympathetic responses to arterial pressure decreases are unchanged.