Differential Lung Ventilation with Unilateral PEEP Following Unilateral Hydrochloric Acid Aspiration in the Dog

Differential lung ventilation with positive end expiratory pressure (PEEP) improves pulmonary gas exchange when used in the supportive care of patients with severe unilateral or asymmetrical lung disease. Once the provision of selective PEEP to the two lungs is accomplished, the best method of partitioning the tidal volume between the two lungs is unknown. Twelve mongrel dogs were given a unilateral hydrochloric acid (HCl) aspiration injury. A computer controlled differential lung ventilation system was used to ventilate four dogs with equal volumes to each lung, four dogs with equal driving pressure (end inspiratory pressure-PEEP) to each lung, and four dogs with equal end-tidal CO₂ fraction from each lung. The respiratory rate was feedback controlled to maintain Paco₂ at 4.67 kPa. The dogs were kept supine and ventilated with 30% O₂. Following injury, the PEEP was set at 0 kPa for 1 h. The dogs were then given 1.36 kPa and 2.72 kPa PEEP to the injured lung for 2 h in a cross-over fashion. The assignment of the tidal volume controller, the side of injury, and the PEEP sequence was random. Oxygen tension fell and pulmonary venous admixture increased after giving the HCl injury. In all three groups considered simultaneously, unilateral PEEP improved Pao₂ and venous admixture. The equal tidal volume distribution was the only group to show a significant improvement in Pao₂ at both PEEP increments (0 to 1.36 kPa and 2.72 kPa). There was a significant difference in tidal volume allocation between the three groups with the equal end-tidal and equal pause pressure groups only minimally ventilating the injured lung. With differential lung ventilation and unilateral PEEP, equal partitioning of tidal volume provides the highest Pao₂, compared to the other two methods of partitioning tidal volume.     

Discrepancy between training,competition and laboratory measures of maximum heart rate in NCAA division 2 distance runners

A percentage of either measured or predicted maximum heart rate is commonly used to prescribe and measure exercise intensity. However, maximum heart rate in athletes may be greater during competition or training than during laboratory exercise testing. Thus, the aim of the present investigation was to determine if endurance-trained runners train and compete at or above laboratory measures of ''maximum'' heart rate. Maximum heart rates were measured utilising a treadmill graded exercise test (GXT) in a laboratory setting using 10 female and 10 male National Collegiate Athletic Association (NCAA) division 2 cross-country and distance event track athletes. Maximum training and competition heart rates were measured during a high-intensity interval training day (TR HR) and during competition (COMP HR) at an NCAA meet. TR HR (207 ± 5.0 b·min^-1; means ± SEM) and COMP HR (206 ± 4 b·min^-1) were significantly (p < 0.05) higher than maximum heart rates obtained during the GXT (194 ± 2 b·min^-1). The heart rate at the ventilatory threshold measured in the laboratory occurred at 83.3 ± 2.5% of the heart rate at VO₂ max with no differences between the men and women. However, the heart rate at the ventilatory threshold measured in the laboratory was only 77% of the maximal COMP HR or TR HR. In order to optimize training-induced adaptation, training intensity for NCAA division 2 distance event runners should not be based on laboratory assessment of maximum heart rate, but instead on maximum heart rate obtained either during training or during competition.

Key points

• A percentage of maximum heart rate is commonly used to prescribe and measure exercise intensity. However, maximum heart rate may be greater during competition or training than during laboratory exercise testing.
• Heart rates during training and competition were significantly higher than maximum heart rates obtained during laboratory exercise testing.
• To optimize training-induced adaptation, training intensity for NCAA division 2 distance event runners should not be based on laboratory assessment of maximum heart rate, but instead on maximum heart rate measure obtained either during training or during competition.

Key words: Competition, heart rate, laboratory, performance, running, training     

The predictive value of serum myeloperoxidase for vasospasm in patients with aneurysmal subarachnoid hemorrhage

Vasospasm is a major contributor to morbidity and mortality in aneurysmal subarachnoid hemorrhage (SAH), with inflammation playing a key role in its pathophysiology. Myeloperoxidase (MPO), an inflammatory marker, was examined as a potential marker of vasospasm in patients with SAH. Daily serum samples from patients with aneurysmal SAH were assayed for MPO, and transcranial Doppler (TCDs) and neurological exams were assessed to determine vasospasm. Suspected vasospasm was confirmed by angiography. Peak MPO levels were then compared with timing of onset of vasospasm, based on clinical exams, TCDs and cerebral angiography. Patients with vasospasm had a mean MPO level of 115.5?ng/ml, compared to 59.4?ng/ml in those without vasospasm, 42.0?ng/ml in those with unruptured aneurysms, and 4.3?ng/ml in normal controls. In patients who experienced vasospasm, MPO was elevated above the threshold on the day of, or at any point prior to, vasospasm in 10 of 15 events (66.7%), and on the day of, or within 2?days prior to, vasospasm in 8 of 15 events (53.3%). Elevated serum MPO correlates with clinically evident vasospasm following aneurysmal SAH. The potential utility of MPO as a marker of vasospasm is discussed.     

Obesity Surgery in the Philippines: Experience in a Private Tertiary Care Hospital for Years 2002 to 2004

Background Information on experience in bariatric surgery in the Asia-Pacific region is minimal: hence the need for more reports from this area. Methods The procedures of bariatric surgery and outcome as part of a weight management program in a tertiary care private hospital in the Philippines is reported from years 2002 to 2004. 50 patients were included, of which 60% underwent laparoscopic adjustable gastric banding (LAGB) and 40% Roux-en- Y gastric bypass (RYGBP). Results There were more females than males (64% vs 36%) with the mean age 38 ± 13.1 years. Initial mean BMI was 46.2 kg/m2, which decreased to 27.0 kg/m² in 1 year. Initial mean weight was 126.7 ± 25.4 kg, of which the 1 year weight loss was 32.3 kg for the morbidly obese and 58.0 kg for the super obese. %EWL at 1 year was 30.2%. There was greater weight loss with RYGBP compared to LAGB at 1 year (43.5 kg vs 30.2 kg). There was no mortality, and early complications were: wound infection (2/50 or 4%), and 1/50 or 2% each for pneumonia, dehydration, gastritis, and leakage. Late complications were: band slippage (2/20 or 10%), stomal stenosis (1/20 or 5%), and ventral hernia (1/5 or 20%). Conclusion Bariatric surgery is safe with a low complication rate and the outcome was similar to the reported data from Asia and the western world.     

鞘内注射miR-212反义锁核酸对骨癌小鼠痛行为的影响

目的研究骨癌痛发展和维持过程中小鼠脊髓水平miR-212表达的变化规律及连续鞘内注射miR-212反义锁核酸LNA．anti—miR-212对骨癌痛小鼠痛行为的影响。方法本实验分为两个部分：（一）骨癌痛小鼠脊髓水平miR-212表达的变化规律：C3H／HeJ雄性小鼠36只,随机分为假手术组（sham组,n=18）和肿瘤组（T组,n=18）。sham组小鼠在右侧股骨远端骨髓腔注射不含肿瘤细胞的仪一MEM,T组小鼠在右侧股骨远端骨髓腔注射纤维肉瘤细胞NCTC2472,建立骨癌痛模型。在术前1d,术后4d、7d、10d、14d、21d,sham组和T组各随机取三只小鼠处死,取脊髓腰膨大标本,用Real-timePCR的方法检测脊髓水平miR一212的表达情况。（二）连续鞘内注射LNA—anti-miR-212对骨癌痛小鼠痛行为的影响：C3H／HeJ雄性小鼠24只,随机分为四组：L组（鞘内注射LNA-anti—miR一212,n=6）、L’组（鞘内注射LNA＇-negativecontrol,n=6）、C组（鞘内注射溶媒无核酸酶水,n=6）和S组（假手术处理,n=6）。L组、L’组和C组小鼠在右侧股骨远端注射纤维肉瘤细胞NCTC2472,S组小鼠在右侧股骨远端骨髓腔注射不含肿瘤细胞的仪一MEM。所有小鼠于术前1d、术后4d、7d、10d、14d测小鼠痛行为指标,包括自发抬足次数和机械缩足阈值（PWMT）,术后14d,L组、L’组、C组小鼠分别鞘内注射LNA—anti—miR-21212pmol／5山、LNA＇-negativecontrol12pmol／5I＊1和无核酸酶水5I＊1,连续鞘内注射7d,1次／d,每天测小鼠痛行为指标,至术后第21天。结果miR-212的表达变化表现为：与基础值相比,sham组和T组小鼠在术后第4天,脊髓水平miR一212明显升高（P〈0．05）;与基础值和sham组相比,T组小鼠脊髓水平miR-212在术后7d、10d、14d、21d均明显升高（P〈0．05）。连续鞘内注射LNA—anti—miR-212改善骨癌痛小鼠痛行为：术后19d至21d,与L’组和c组相比,L组小鼠PWMT[19d（1．07-4-0．16）g,20d（1．13±0．21）g,21d（1．27±0．21）g）]明显升高（P〈0．05）,自发抬足次数明显降低[19d（6．674-1．04）,20d（6．62±1．39）,21d（6．47±1．17）]（P〈0．05）。与14d给药前相比,L组小鼠术后19d至21d的PWMT明显升高（P〈0．05）,自发抬足次数明显降低（P〈0．05）。结论骨癌痛发展过程中,脊髓水平miR-212表达量升高。连续鞘内注射LNA-anti—miR一212可以缓解骨癌小鼠痛行为。     

Clinically relevant pretraining is all you need

Clinical notes present a wealth of information for applications in the clinical domain, but heterogeneity across clinical institutions and settings presents challenges for their processing. The clinical natural language processing field has made strides in overcoming domain heterogeneity, while pretrained deep learning models present opportunities to transfer knowledge from one task to another. Pretrained models have performed well when transferred to new tasks; however, it is not well understood if these models generalize across differences in institutions and settings within the clinical domain. We explore if institution or setting specific pretraining is necessary for pretrained models to perform well when transferred to new tasks. We find no significant performance difference between models pretrained across institutions and settings, indicating that clinically pretrained models transfer well across such boundaries. Given a clinically pretrained model, clinical natural language processing researchers may forgo the time-consuming pretraining step without a significant performance drop.