Beneficial Effects of N-Acetyl Cysteine on Pancreas and Kidney Following Experimental Pancreatic Ischemia-Reperfusion in Rats

OBJECTIVE:

To evaluate the protective effects of N-acetyl cysteine on the pancreas and kidney after pancreatic ischemia reperfusion injury in a rat model.

METHODS AND MATERIALS:

Pancreatic ischemia reperfusion was performed in Wistar rats for 1 hour. Revascularization was achieved followed by 4 h of reperfusion. A total of 24 animals were divided into four groups: Group 1: sham; Group 2: pancreatic ischemia reperfusion without treatment; Group 3: pancreatic ischemia reperfusion plus N-acetyl cysteine intravenously; and Group 4: pancreatic ischemia reperfusion plus N-acetyl cysteine per os. Blood and tissue samples were collected after reperfusion.

RESULTS:

There were significant differences in amylase levels between Group 1 (6.11±0.55) and Group 2 (10.30±0.50) [p=0.0002] as well as between Group 2 (10.30±0.50) and Group 4 (7.82±0.38) [p=0.003]; creatinine levels between Group 1 (0.52 ± 0.07) and Group 2 (0.77±0.18) [p=0.035] as well as between Group 2 (0.77±0.18) and Group 3 (0.48±0.13) [p=0.012]; and pancreatic tissue thiobarbituric acid reactive substance levels between Group 1 (1.27±0.96) and Group 2 (2.60±3.01) [p=0.026] as well as between Group 2 (2.60±3.01) and Group 4 (0.52±0.56) [p=0.002]. A decrease in pancreatic tissue GST-α3 gene expression was observed in Group 2 in comparison to Group 1 (p =0.006), and an increase was observed in Groups 3 and 4 when compared to Group 2 (p= 0.025 and p=0.010, respectively).

CONCLUSION:

This study provides evidence that N-acetyl cysteine has a beneficial effect on pancreatic ischemia reperfusion injury and renal function in a rat model.     

Local and remote ischemic preconditioning protect against intestinal ischemic/reperfusion injury after supraceliac aortic clamping

OBJECTIVES:

This study tests the hypothesis that local or remote ischemic preconditioning may protect the intestinal mucosa against ischemia and reperfusion injuries resulting from temporary supraceliac aortic clamping.

METHODS:

Twenty-eight Wistar rats were divided into four groups: the sham surgery group, the supraceliac aortic occlusion group, the local ischemic preconditioning prior to supraceliac aortic occlusion group, and the remote ischemic preconditioning prior to supraceliac aortic occlusion group. Tissue samples from the small bowel were used for quantitative morphometric analysis of mucosal injury, and blood samples were collected for laboratory analyses.

RESULTS:

Supraceliac aortic occlusion decreased intestinal mucosal length by reducing villous height and elevated serum lactic dehydrogenase and lactate levels. Both local and remote ischemic preconditioning mitigated these histopathological and laboratory changes.

CONCLUSIONS:

Both local and remote ischemic preconditioning protect intestinal mucosa against ischemia and reperfusion injury following supraceliac aortic clamping.     

Preconditioning of the response to ischemia/ reperfusion-induced plasma leakage in hamster cheek pouch microcirculation

OBJECTIVE:

Ischemic preconditioning and some drugs can protect tissues from injury by preserving microcirculation. This study evaluated vascular permeability in a hamster cheek pouch preparation using either short ischemic periods or bradykinin as preconditioning stimuli followed by 30 min of ischemia/reperfusion.

METHOD:

Sixty-six male hamsters were divided into 11 groups: five combinations of different ischemic frequencies and durations (one, three or five shorts periods of ischemia, separated by one or five minutes) with 10 min intervals between the ischemic periods, followed by 30 min ischemia/reperfusion; three or five 1 min ischemic periods with 10 min intervals between them followed by the topical application of histamine (2 µM); bradykinin (400 nM) followed by 30 min of ischemia/reperfusion; and three control groups (30 min of ischemia/reperfusion or histamine or bradykinin by themselves). Macromolecular permeability was assessed by injection of fluorescein-labeled dextran (FITC-dextran, MW = 150 kDa; 250 mg/Kg body weight), and the number of leaks/cm2 was counted using an intravital microscope and fluorescent light in the cheek pouch.

RESULTS:

Plasma leakage (number of leaks/cm²) was significantly reduced by preconditioning with three and five 1 min ischemic periods, one and three 5 min ischemic periods and by bradykinin. Histamine-induced macromolecular permeability was also reduced after three periods of 5 min of ischemia.

CONCLUSION:

Short ischemic periods and bradykinin can function as preconditioning stimuli of the ischemia/reperfusion response in the hamster cheek pouch microcirculation. Short ischemic periods also reduced histamine-induced macromolecular permeability.     

Evaluation of the effects of ischemic preconditioning on the hematological parameters of rats subjected to intestinal ischemia and reperfusion

OBJECTIVES:

Intestinal ischemia/reperfusion often leads to acute lung injury and multiple organ failure. Ischemic preconditioning is protective in nature and reduces tissue injuries in animal and human models. Although hematimetric parameters are widely used as diagnostic tools, there is no report of the influence of intestinal ischemia/reperfusion and ischemic preconditioning on such parameters. We evaluated the hematological changes during ischemia/reperfusion and preconditioning in rats.

METHODS:

Forty healthy rats were divided into four groups: control, laparotomy, intestinal ischemia/reperfusion and ischemic preconditioning. The intestinal ischemia/reperfusion group received 45 min of superior mesenteric artery occlusion, while the ischemic preconditioning group received 10 min of short ischemia and reperfusion before 45 min of prolonged occlusion. A cell counter was used to analyze blood obtained from rats before and after the surgical procedures and the hematological results were compared among the groups.

RESULTS:

The results showed significant differences in hematimetric parameters among the groups. The parameters that showed significant differences included lymphocyte, white blood cells and granulocyte counts; hematocrit; mean corpuscular hemoglobin concentration; red cell deviation width; platelet count; mean platelet volume; plateletcrit and platelet distribution width.

CONCLUSION:

The most remarkable parameters were those related to leukocytes and platelets. Some of the data, including the lymphocyte and granulocytes counts, suggest that ischemic preconditioning attenuates the effect of intestinal ischemia/reperfusion on circulating blood cells. Our work contributes to a better understanding of the hematological responses after intestinal ischemia/reperfusion and IPC, and the present findings may also be used as predictive values.     

Ethyl pyruvate has anti-inflammatory and delayed myocardial protective effects after regional ischemia/reperfusion injury

Purpose

Ethyl pyruvate has anti-inflammatory properties and protects organs from ischemia/reperfusion (I/R)-induced tissue injury. The aim of this study was to determine whether ethyl pyruvate decreases the inflammatory response after regional I/R injury and whether ethyl pyruvate protects against delayed regional I/R injury in an in vivo rat heart model after a 24 hours reperfusion.

Materials and Methods

Rats were randomized to receive lactated Ringer''s solution or ethyl pyruvate dissolved in Ringer''s solution, which was given by intraperitoneal injection 1 hour prior to ischemia. Rats were subjected to 30 min of ischemia followed by reperfusion of the left coronary artery territory. After a 2 hours reperfusion, nuclear factor κB, myocardial myeloperoxidase activity, and inflammatory cytokine levels were determined. After the 24 hours reperfusion, the hemodynamic function and myocardial infarct size were evaluated.

Results

At 2 hours after I/R injury, ethyl pyruvate attenuated I/R-induced nuclear factor κB translocation and reduced myeloperoxidase activity in myocardium. The plasma circulating levels of inflammatory cytokines decreased significantly in the ethyl pyruvate-treated group. At 24 hours after I/R injury, ethyl pyruvate significantly improved cardiac function and reduced infarct size after regional I/R injury.

Conclusion

Ethyl pyruvate has the ability to inhibit neutrophil activation, inflammatory cytokine release, and nuclear factor κB translocation. Ethyl pyruvate is associated with a delayed myocardial protective effect after regional I/R injury in an in vivo rat heart model.     

Limb blood flow after class 4 laser therapy

Context:

Laser therapy is purported to improve blood flow in soft tissues. Modulating circulation would promote healing by controlling postinjury ischemia, hypoxia, edema, and secondary tissue damage. However, no studies have quantified these responses to laser therapy.

Objective:

To determine a therapeutic dose range for laser therapy for increasing blood flow to the forearm.

Design:

Crossover study.

Setting:

Controlled laboratory setting.

Patients or Other Participants:

Ten healthy, college-aged men (age = 20.80 ± 2.16 years, height = 177.93 ± 3.38 cm, weight = 73.64 ± 9.10 kg) with no current history of injury to the upper extremity or cardiovascular conditions.

Intervention(s):

A class 4 laser device was used to treat the biceps brachii muscle. Each grid point was treated for 3 to 4 seconds, for a total of 4 minutes. Each participant received 4 doses of laser therapy: sham, 1 W, 3 W, and 6 W.

Main Outcome Measure(s):

The dependent variables were changes in blood flow, measured using venous occlusion plethysmography. We used a repeated-measures analysis of variance to analyze changes in blood flow for each dose at 2, 3, and 4 minutes and at 1, 2, 3, 4, and 5 minutes after treatment. The Huynh-Feldt test was conducted to examine differences over time.

Results:

Compared with baseline, blood flow increased over time with the 3-W treatment (F_3,9 = 3.468, P < .011) at minute 4 of treatment (2.417 ± 0.342 versus 2.794 ± 0.351 mL/min per 100 mL tissue, P = .032), and at 1 minute (2.767 ± 0.358 mL/min per 100 mL tissue, P < .01) and 2 minutes (2.657 ± 0.369 mL/min per 100 mL tissue, P = .022) after treatment. The sham, 1-W, and 6-W treatment doses did not change blood flow from baseline at any time point.

Conclusions:

Laser therapy at the 3-W (360-J) dose level was an effective treatment modality to increase blood flow in the soft tissues.     

Sweat Rates, Sweat Sodium Concentrations, and Sodium Losses in 3 Groups of Professional Football Players

Context:

Sweat sodium losses have never been reported in a large cohort of American football players.

Objective:

To compare sweat rates (SwtRs), sweat sodium concentrations (SwtNa⁺), and sodium losses in 3 groups of players (backs and receivers [BK], linebackers and quarterbacks [LB/QB], and linemen [LM]) to determine if positional differences and, therefore, size differences exist.

Design:

Observational study.

Setting:

Data were collected during practices in the second week of 2 consecutive training camps. The wet bulb globe temperature was 78.5°F ± 3.5°F (25.9°C ± 1.9°C).

Patients or Other Participants:

Eighteen BK, 12 LB/QB, and 14 LM volunteered.

Intervention(s):

Sterile sweat patches were applied to the right forearm after the skin was appropriately cleaned. The patches were removed during practice, placed in sterile tubes, centrifuged, frozen, and later analyzed by flame photometry.

Main Outcome Measure(s):

Sweat rate, SwtNa⁺, and sodium loss. We calculated SwtR by change in mass adjusted for urine produced and fluids consumed divided by practice time in hours.

Results:

Other than age, physical characteristics were different among groups (P < .001). The SwtR was different among groups (F_2,41  =  7.3, P  =  .002). It was lower in BK (1.42 ± 0.45 L/h) than in LB/QB (1.98 ± 0.49 L/h) (P < .05) and LM (2.16 ± 0.75 L/h) (P < .01), but we found no differences between SwtRs for LB/QB and LM. The SwtNa⁺ was not different among groups (BK  =  50 ± 16 mEq/L, LB/QB  =  48.2 ± 23 mEq/L, and LM  =  52.8 ± 25 mEq/L) and ranged from 15 to 99 mEq/L. Sweat sodium losses ranged from 642 mg/h to 6.7 g/h, and findings for group comparisons approached significance (P  =  .06). On days when players practiced 4.5 hours, calculated sodium losses ranged from 2.3 to 30 g/d.

Conclusions:

The BK sweated at lower rates than did the midsized LB/QB and large LM, but LB/QB sweated similarly to LM. Sweat sodium concentration and daily sodium losses ranged considerably. Heavy, salty sweaters require increased dietary consumption of sodium during preseason.     

Sex differences, hormone fluctuations, ankle stability, and dynamic postural control

Context:

Hormonal fluctuation as a risk factor in anterior cruciate ligament injury has been investigated with conflicting results. However, the influence of hormone fluctuations on ankle laxity and function has not been thoroughly examined.

Objective:

To examine the potential hormone contributions to ankle laxity and dynamic postural control during the preovulatory and postovulatory phases of the menstrual cycle using an ankle arthrometer and the Star Excursion Balance Test in healthy women. The cohort group consisted of male control participants.

Design:

Cohort study.

Setting:

Research laboratory.

Patients or Other Participants:

Twenty healthy women (age = 23.8 ± 6.50 years, height = 163.88 ± 8.28 cm, mass = 63.08 ± 12.38 kg) and 20 healthy men (age = 23.90 ± 4.15 years, height = 177.07 ± 7.60 cm, mass = 80.57 ± 12.20 kg).

Intervention(s):

Ankle stability was assessed with anterior-posterior and inversion-eversion loading. Dynamic postural control was assessed with the posteromedial reaching distance of the Star Excursion Balance Test.

Main Outcome Measure(s):

Female participants used ovulation kits for 3 months to determine the time of ovulation; during their preovulatory and postovulatory phases, they were tested in the laboratory with an ankle arthrometer and the Star Excursion Balance Test. Male participants were tested on similar dates as controls. For each dependent variable, a time by side by sex repeated-measures analysis of variance was performed. Statistical significance was set a priori at P < .05.

Results:

For anterior-posterior laxity, a side main effect was noted (F_1,38 = 10.93, P = .002). For inversion-eversion laxity, a sex main effect was seen (F_1,38 = 10.75, P = .002). For the posteromedial reaching task, a sex main effect was demonstrated (F_1,38 = 8.72, P = .005). No influences of time on the dependent variables were evident.

Conclusions:

Although women presented with more ankle inversion-eversion laxity and less dynamic postural control, hormonal fluctuations during the menstrual cycle (preovulatory compared with postovulatory) did not affect ankle laxity or dynamic postural control, 2 factors that are associated with ankle instability.     

Olmesartan restores the protective effect of remote ischemic perconditioning against myocardial ischemia/reperfusion injury in spontaneously hypertensive rats

OBJECTIVES:Remote ischemic perconditioning is the newest technique used to lessen ischemia/reperfusion injury. However, its effect in hypertensive animals has not been investigated. This study aimed to examine the effect of remote ischemic perconditioning in spontaneously hypertensive rats and determine whether chronic treatment with Olmesartan could influence the effect of remote ischemic perconditioning.METHODS:Sixty rats were randomly divided into six groups: vehicle-sham, vehicle-ischemia/reperfusion injury, vehicle-remote ischemic perconditioning, olmesartan-sham, olmesartan-ischemia/reperfusion and olmesartan-remote ischemic perconditioning. The left ventricular mass index, creatine kinase concentration, infarct size, arrhythmia scores, HIF–1α mRNA expression, miR-21 expression and miR-210 expression were measured.RESULTS:Olmesartan significantly reduced the left ventricular mass index, decreased the creatine kinase concentration, limited the infarct size and reduced the arrhythmia score. The infarct size, creatine kinase concentration and arrhythmia score during reperfusion were similar for the vehicle-ischemia/reperfusion group and vehicle-remote ischemic perconditioning group. However, these values were significantly decreased in the olmesartan-remote ischemic perconditioning group compared to the olmesartan-ischemia/reperfusion injury group. HIF–1α, miR-21 and miR-210 expression were markedly down-regulated in the Olmesartan-sham group compared to the vehicle-sham group and significantly up-regulated in the olmesartan-remote ischemic perconditioning group compared to the olmesartan-ischemia/reperfusion injury group.CONCLUSION:The results indicate that ¹ the protective effect of remote ischemic perconditioning is lost in vehicle-treated rats and that chronic treatment with Olmesartan restores the protective effect of remote ischemic perconditioning; ² chronic treatment with Olmesartan down-regulates HIF–1α, miR-21 and miR-210 expression and reduces hypertrophy, thereby limiting ischemia/reperfusion injury; and ³ recovery of the protective effect of remote ischemic perconditioning is related to the up-regulation of HIF–1α, miR-21 and miR-210 expression.     

Two different fatigue protocols and lower extremity motion patterns during a stop-jump task

Context:

Altered neuromuscular control strategies during fatigue probably contribute to the increased incidence of non-contact anterior cruciate ligament injuries in female athletes.

Objective:

To determine biomechanical differences between 2 fatigue protocols (slow linear oxidative fatigue protocol [SLO-FP] and functional agility short-term fatigue protocol [FAST-FP]) when performing a running-stop-jump task.

Design:

Controlled laboratory study.

Setting:

Laboratory.

Patients or Other Participants:

A convenience sample of 15 female soccer players (age = 19.2 ±0.8 years, height = 1.67±0.05m, mass = 61.7 + 8.1 kg) without injury participated.

Intervention(s):

Five successful trials of a running–stop-jump task were obtained prefatigue and postfatigue during the 2 protocols. For the SLO-FP, a peak oxygen consumption (V˙o₂peak) test was conducted before the fatigue protocol. Five minutes after the conclusion of the V˙o₂peak test, participants started the fatigue protocol by performing a 30-minute interval run. The FAST-FP consisted of 4 sets of a functional circuit. Repeated 2 (fatigue protocol) × 2 (time) analyses of variance were conducted to assess differences between the 2 protocols and time (prefatigue, postfatigue).

Main Outcome Measure(s):

Kinematic and kinetic measures of the hip and knee were obtained at different times while participants performed both protocols during prefatigue and postfatigue.

Results:

Internal adduction moment at initial contact (IC) was greater during FAST-FP (0.064 ±0.09 Nm/kgm) than SLO-FP (0.024±0.06 Nm/kgm) (F_1,14 = 5.610, P=.03). At IC, participants had less hip flexion postfatigue (44.7°±8.1°) than prefatigue (50.1°±9.5°) (F_1,14 = 16.229, P=.001). At peak vertical ground reaction force, participants had less hip flexion postfatigue (44.7°±8.4°) than prefatigue (50.4°±10.3°) (F_1,14 = 17.026, P=.001). At peak vertical ground reaction force, participants had less knee flexion postfatigue (−35.9°±6.5°) than prefatigue (−38.8°±5.03°) (F_1,14 = 11.537, P=.001).

Conclusions:

Our results demonstrated a more erect landing posture due to a decrease in hip and knee flexion angles in the postfatigue condition. The changes were similar between protocols; however, the FAST-FP was a clinically applicable 5-minute protocol, whereas the SLO-FP lasted approximately 45 minutes.     

Heat stress and cardiovascular, hormonal, and heat shock proteins in humans

Context:

Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases.

Objective:

To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extra-cellular protein responses of exercise.

Design:

Randomized controlled trial.

Setting:

University research laboratory.

Patients or Other Participants:

Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered.

Intervention(s):

Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress.

Main Outcome Measure(s):

Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception.

Results:

After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F_6,24 = 186, P < .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F_6,24 = 10.1, P < .001) and 5 mm Hg (F_6,24 = 5.4, P < .001), respectively. Norepinephrine (F_1,12 = 12.1, P = .004) and prolactin (F_1,12 = 30.2, P < .001) increased in the plasma (58% and 285%, respectively) (P < .05). The HSP72 (F_1,12 = 44.7, P < .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials.

Conclusions:

We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether carefully prescribed heat stress constitutes a method to augment or supplement exercise.     

Gastric emptying after pickle-juice ingestion in rested, euhydrated humans

Context:

Small volumes of pickle juice (PJ) relieve muscle cramps within 85 seconds of ingestion without significantly affecting plasma variables. This effect may be neurologic rather than metabolic. Understanding PJ''s gastric emptying would help to strengthen this theory.

Objective:

To compare gastric emptying and plasma variables after PJ and deionized water (DIW) ingestion.

Design:

Crossover study.

Setting:

Laboratory.

Patients or Other Participants:

Ten men (age  =  25.4 ± 0.7 years, height  =  177.1 ± 1.6 cm, mass  =  78.1 ± 3.6 kg).

Intervention(s):

Rested, euhydrated, and eunatremic participants ingested 7 mL·kg⁻¹ body mass of PJ or DIW on separate days.

Main Outcome Measure(s):

Gastric volume was measured at 0, 5, 10, 20, and 30 minutes postingestion (using the phenol red dilution technique). Percentage changes in plasma volume and plasma sodium concentration were measured preingestion (−45 minutes) and at 5, 10, 20, and 30 minutes postingestion.

Results:

Initial gastric volume was 624.5 ± 27.4 mL for PJ and 659.5 ± 43.8 mL for DIW (P > .05). Both fluids began to empty within the first 5 minutes (volume emptied: PJ  =  219.2 ± 39.1 mL, DIW  =  305.0 ± 40.5 mL, P < .05). Participants who ingested PJ did not empty further after the first 5 minutes (P > .05), whereas in those who ingested DIW, gastric volume decreased to 111.6 ± 39.9 mL by 30 minutes (P < .05). The DIW group emptied faster than the PJ group between 20 and 30 minutes postingestion (P < .05). Within 5 minutes of PJ ingestion, plasma volume decreased 4.8% ± 1.6%, whereas plasma sodium concentration increased 1.6 ± 0.5 mmol·L⁻¹ (P < .05). Similar changes occurred after DIW ingestion. Calculated plasma sodium content was unchanged for both fluids (P > .05).

Conclusions:

The initial decrease in gastric volume with both fluids is likely attributable to gastric distension. Failure of the PJ group to empty afterward is likely due to PJ''s osmolality and acidity. Cardiovascular reflexes resulting from gastric distension are likely responsible for the plasma volume shift and rise in plasma sodium concentration despite nonsignificant changes in plasma sodium content. These data support our theory that PJ does not relieve cramps via a metabolic mechanism.     

Contribution of Knee Flexor and Extensor Strength on Sex-Specific Energy Absorption and Torsional Joint Stiffness During Drop Jumping

Context:

Lower extremity injury often occurs during abrupt deceleration when attempting to change the body''s direction. Although sex-specific biomechanics have been implicated in the greater risk of acute knee injury in women than in men, it is unknown if sex differences in thigh strength affect sex-specific energy absorption and torsional joint stiffness patterns.

Objective:

To determine sex differences in energy absorption patterns and joint stiffnesses of the lower extremity during a drop jump and to determine if these sex differences were predicted by knee extensor and flexor strength.

Design:

Cross-sectional study.

Setting:

Laboratory environment.

Patients or Other Participants:

Recreationally active, college-aged students (41 women: age  =  22.1 ± 2.9 years, height  =  1.63 ± 0.07 m, mass  =  59.3 ± 8.0 kg; 40 men: age  =  22.4 ± 2.8 years, height  =  1.77 ± 0.1 m, mass  =  80.9 ± 14.1 kg).

Intervention(s):

Participants performed knee flexor and extensor maximal voluntary isometric contractions followed by double-leg drop-jump landings.

Main Outcome Measure(s):

Lower extremity joint energetics (J × N⁻¹ × m⁻¹) and torsional joint stiffnesses (Nm × N⁻¹ × m⁻¹ × degrees⁻¹) were calculated for the hip, knee, and ankle during the initial landing phase. Body weight was measured in newtons and height was measured in meters. Sex comparisons were made and sex-specific regressions determined if thigh muscle strength (Nm/kg) predicted sagittal-plane landing energetics and stiffnesses.

Results:

Women absorbed 69% more knee energy and had 36% less hip torsional stiffness than men. In women, greater knee extensor strength predicted greater knee energy absorption (R²  =  0.11, P  =  .04), and greater knee flexor strength predicted greater hip torsional stiffness (R²  =  0.12, P  =  .03).

Conclusions:

Sex-specific biomechanics during the deceleration phase of a drop jump revealed that women used a strategy to attempt to decrease system stiffness. Additionally, only female strength values were predictive of landing energetics and stiffnesses. These findings collectively demonstrated that the task may have been more difficult for women, resulting in a different movement strategy among those with different levels of thigh strength to safely complete the task. Future researchers should look at other predictive factors of observed sex differences.     

Craniofacial Phenotyping in Obstructive Sleep Apnea – A Novel Quantitative Photographic Approach

Study Objectives:

To compare the craniofacial morphological phenotype of subjects with and without obstructive sleep apnea (OSA) using a quantitative photographic analysis technique.

Design:

Case-control study; subgroup matched for body mass index (BMI) and sex.

Setting:

Sleep investigation unit in a university teaching hospital.

Patients:

114 subjects (93% Caucasian) with OSA (apnea-hypopnea index [AHI] ≥ 10/h) and 66 controls (AHI < 10/h).

Interventions:

Standardized frontal-profile craniofacial photographic imaging performed prior to polysomnography. Photographs were analyzed for the computation of linear, angular, area and polyhedral volume measurements representing dimensions and relationships of the various craniofacial regions.

Measurements and Results:

Photographic craniofacial phenotypic differences were demonstrated between OSA and control subjects, including a range of measurements of the face, mandible, maxilla, eyes, nose, head and neck. After 1-for-1 subgroup matching for BMI and sex (51 subjects in each group), mandibular length 1 (6.21 ± 0.08 [mean ± SEM] vs 6.58 ± 0.08 cm, P = 0.006), mandibular-nasion angle 1 (35.0 ± 0.48 vs 36.7 ± 0.37 degrees, P = 0.006) and anterior neck space area (10.2 ± 0.53 vs 12.2 ± 0.52 cm², P = 0.01) remained smaller in the OSA group. Mandibular width-length angle (88.0 ± 0.75 vs 85.3 ± 0.54 degrees, P = 0.005) and face width-midface depth angle (72.3 ± 0.44 vs 70.7 ± 0.39 degrees, P = 0.01) remained larger in the OSA group, whereas mandibular triangular area (39.2 ± 0.63 vs 41.7 ± 0.74 cm², P = 0.01) was smaller.

Conclusions:

Craniofacial phenotypic differences in OSA in Caucasian subjects can be demonstrated using a photographic analysis technique.

Citation:

Lee RWW; Chan ASL; Grunstein RR; Cistulli PA. Craniofacial phenotyping in obstructive sleep apnea – a novel quantitative photographic approach. SLEEP 2009;32(1):37–45.     

Comparison of lung preservation solutions in human lungs using an ex vivo lung perfusion experimental model

OBJECTIVE:

Experimental studies on lung preservation have always been performed using animal models. We present ex vivo lung perfusion as a new model for the study of lung preservation. Using human lungs instead of animal models may bring the results of experimental studies closer to what could be expected in clinical practice.

METHOD:

Brain-dead donors whose lungs had been declined by transplantation teams were used. The cases were randomized into two groups. In Group 1, Perfadex® was used for pulmonary preservation, and in Group 2, LPDnac, a solution manufactured in Brazil, was used. An ex vivo lung perfusion system was used, and the lungs were ventilated and perfused after 10 hours of cold ischemia. The extent of ischemic-reperfusion injury was measured using functional and histological parameters.

RESULTS:

After reperfusion, the mean oxygenation capacity was 405.3 mmHg in Group 1 and 406.0 mmHg in Group 2 (p = 0.98). The mean pulmonary vascular resistance values were 697.6 and 378.3 dyn·s·cm^-5, respectively (p = 0.035). The mean pulmonary compliance was 46.8 cm H₂O in Group 1 and 49.3 ml/cm H₂O in Group 2 (p = 0.816). The mean wet/dry weight ratios were 2.06 and 2.02, respectively (p = 0.87). The mean Lung Injury Scores for the biopsy performed after reperfusion were 4.37 and 4.37 in Groups 1 and 2, respectively (p = 1.0), and the apoptotic cell counts were 118.75/mm² and 137.50/mm², respectively (p = 0.71).

CONCLUSION:

The locally produced preservation solution proved to be as good as Perfadex®. The clinical use of LPDnac may reduce costs in our centers. Therefore, it is important to develop new models to study lung preservation.     

Tibiofemoral Joint Positioning for the Valgus Stress Test

Context:

Recommendations on the positioning of the tibiofemoral joint during a valgus stress test to optimize isolation of the medial collateral ligament (MCL) from other medial joint structures vary in the literature. If a specific amount of flexion could be identified as optimally isolating the MCL, teaching and using the technique would be more consistent in clinical application.

Objective:

To determine the angle of tibiofemoral joint flexion between 0° and 20° that causes a difference in the slope of the force-strain line when measuring the resistance to a valgus force applied to the joint.

Design:

Cross-sectional study.

Setting:

University research laboratory.

Patients or Other Participants:

Twelve healthy volunteers (6 men, 6 women: age  =  26.4 ± 5.6 years, height  =  170.9 ± 8.4 cm, mass  =  75.01 ± 14.6 kg).

Intervention(s):

Using an arthrometer, we applied a valgus force, over a range of 60 N, to the tibiofemoral joint in 0°, 5°, 10°, 15°, and 20° of flexion.

Main Outcome Measure(s):

Force-strain measurements were obtained for 5 positions of tibiofemoral joint flexion.

Results:

As knee flexion angle increased, slope values decreased (F_4,44  =  17.6, P < .001). The slope at full extension was not different from that at 5° of flexion, but it was different from the slopes at angles greater than 10° of flexion. Similarly, the slope at 5° of flexion was not different from that at 10° of flexion, but it was different from the slopes at 15° and 20° of flexion. Further, the slope at 10° of flexion was not different from that at 15° or 20° of flexion. Finally, the slope at 15° of flexion was not different from that at 20° of flexion.

Conclusions:

When performing the manual valgus stress test, the clinician should fully extend the tibiofemoral joint or flex it to 5° to assess all resisting medial tibiofemoral joint structures and again at 15° to 20° of joint flexion to further assess the MCL.     

Effects of Urtica dioica on hepatic ischemia-reperfusion injury in rats

OBJECTIVES:

To evaluate the effects of Urtica dioica on hepatic ischemia‐reperfusion injury.

METHODS:

Thirty adult male Wistar albino rats were divided into three groups: sham group (group 1), control group (group 2), and Urtica dioica group (group 3). All the rats were exposed to hepatic ischemia for 60 min, followed by 60 min of reperfusion. In group 2, a total of 2 ml/kg 0.9% saline solution was given intraperitoneally. In group 3, a total of 2 ml/kg Urtica dioica was given intraperitoneally. At the end of the procedure, liver tissue and blood samples were taken from all rats. Serum aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, ceruloplasmin, catalase, paraoxonase, arylesterase, and lipid hydroperoxide levels were measured. Liver tissue histopathologies were also evaluated by light microscopy.

RESULTS:

Serum aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase levels were significantly higher in group 2 than in group 1, and significantly lower in group 3 than in group 2. Also, group 2 had higher serum lipid hydroperoxides and ceruloplasmin levels but lower catalase, paraoxonase, and arylesterase levels than group 1.In group 3, serum lipid hydroperoxides and ceruloplasmin levels were significantly lower, and catalase, paraoxonase, and arylesterase levels were higher than those in group 2. Histopathological examination showed that liver tissue damage was significantly decreased in group 3 compared with group 2.

CONCLUSIONS:

Urtica dioica has a protective effect on the liver in hepatic ischemia‐reperfusion‐injured rats.     

The clinical features of drug-induced liver injury observed through liver biopsy: focus on relevancy to autoimmune hepatitis

Background/Aims

Accurate diagnosis of drug-induced liver injury (DILI) is difficult without considering the possibility of underlying diseases, especially autoimmune hepatitis (AIH). We investigated the clinical patterns in patients with a history of medication, liver-function abnormalities, and in whom liver biopsy was conducted, focusing on accompaniment by AIH.

Methods

The clinical, serologic, and histologic findings of 29 patients were compared and analyzed. The patients were aged 46.2±12.8 years (mean±SD), and 72.4% of patient were female. The most common symptom and causal drug were jaundice (58.6%) and herbal medications (55.2%), respectively.

Results

Aspartate aminotransferase (AST), alanine aminotransferase, total bilirubin, alkaline phosphatase, and γ-glutamyl transpeptidase levels were 662.2±574.8 U/L, 905.4±794.9 U/L, 12.9±10.8 mg/dL, 195.8±123.3 U/L, and 255.3±280.8 U/L, respectively. According to serologic and histologic findings, 21 cases were diagnosed with DILI and 8 with AIH. The AIH group exhibited significantly higher AST levels (537.1±519.1 vs. 1043.3±600.5 U/L), globulin levels (2.7±0.4 vs. 3.3±0.5 g/dL), and prothrombin time (12.9±2.4 vs. 15.2±3.9 s; P<0.05). Antinuclear antibody was positive in 7 of 21 cases of DILI and all 8 cases of AIH (P=0.002). The simplified AIH score was 3.7±0.9 in the DILI group and 6.5±0.9 in the AIH group (P<0.001).

Conclusions

Accurate diagnosis is necessary for patients with a history of medication and visits for liver-function abnormalities; in particular, the possibility of AIH should be considered.     

An assessment of burnout in graduate assistant certified athletic trainers

Context:

Graduate assistant athletic trainers (GAATs) must balance the demands of clinical care and the academic load of graduate-level students.

Objective:

To examine burnout among GAATs with clinical assistantships at National Collegiate Athletic Association (NCAA) Division I institutions and to identify the personal and situational variables that are related to burnout.

Design:

Cross-sectional study.

Setting:

Division I universities offering graduate assistantship programs.

Patients or Other Participants:

Two hundred one GAATs enrolled at NCAA Division I universities with graduate assistantship positions.

Main Outcome Measures(s):

The Athletic Training Burnout Inventory, which assesses stress and burnout among ATs through 4 constructs: emotional exhaustion and depersonalization, administrative responsibility, time commitment, and organizational support. The 6-point Likert scale is anchored by 1 (never true) and 6 (always true).

Results:

The GAATs who traveled with athletic teams (4.051 ± 0.895) and those who provided classroom instruction (4.333 ± 1.16) reported higher levels of stress due to time commitment than those who did not travel (3.713 ± 1.22) or teach (3.923 ± 0.929). We also found a difference in administrative responsibility across clinical settings (F_6,194  =  3.507, P  =  .003). The results showed that GAATs in NCAA Division I clinical settings (44.55 ± 13.17 hours) worked more hours than those in NCAA Division III clinical settings (33.69 ± 12.07 hours) and those in high school settings (30.51 ± 9.934 hours).

Conclusions:

Graduate assistant ATs are at risk for burnout because of the time necessary to complete their clinical and academic responsibilities and their additional administrative responsibilities. Graduate assistants who work in the Division I clinical setting are at greater risk for burnout than those in the secondary school setting because of the large number of hours required.