Effects of hypoxia and reoxygenation on regular contractions and postrest contraction in rat papillary muscles

The effects of hypoxia and reoxygenation on regular contractions and postrest contractions (PRC) of papillary muscle of rats were studied. Isometric tension was measured during two cycles of hypoxia and reoxygenation. Trains of 80 externally continuous stimulations at 40/min were applied. PRCs were evoked by a stimulus train after a 60 sec resting interval. After 90 min of hypoxia (the first hypoxia period), regular contractions and PRCs decreased to 5.6 +/- 2.0% and 23.4 +/- 2.4% of baseline values, respectively (p less than 0.001; n = 18). After 90 min of reoxygenation, the recovery of the PRCs (44.4 +/- 3.4%) was better than that of the regular contractions (23.3 +/- 3.3%) (p less than 0.01; n = 18). After 30 min of hypoxia (the second hypoxic period), regular contractions and PRCs decreased to 2.2 +/- 0.6% and 13.6 +/- 1.6% of baseline values, respectively (p less than 0.001; n = 18). However, the recovery from the second hypoxic injury was not significant for either regular contractions or PRCs. The % diastolic tension, which was normalized to the baseline for regular contractions, increased to 113.2 +/- 6.9% and 133.6 +/- 8.4% at the end of the first and the second hypoxic periods, respectively. There was statistically significant correlation between the % diastolic tension and the % hypoxic injury of PRCs (p less than 0.002; n = 18). There was no significant relationship between % diastolic tension and % hypoxic injury of regular contractions. There was no statistically significant correlation between % diastolic tension and % recovery from the hypoxic injury of either regular contractions or PRCs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Risk appraisal and endoscopic screening for esophageal squamous cell carcinoma in Japanese populations

Epidemiological studies have shown several strong predictors for selecting Japanese persons at high risk for esophageal squamous cell carcinoma (ESCC). (1) Alcohol consumption and tobacco smoking synergistically increase the risk, and a low intake of green and yellow vegetables or fruit and a low body mass index also increase the risk of ESCC. (2) The presence of esophageal distinct iodine-unstained lesions and melanosis are associated with an increased risk of ESCC. (3) The combination of alcohol consumption and inactive heterozygous aldehyde dehydrogenase-2 (ALDH2) and less-active homozygous alcohol dehydrogenase-1B (ADH1B) increases the risk of ESCC in a multiplicative fashion. (4) The results of a simple flushing questionnaire predict the ALDH2 phenotype with a high accuracy. (5) High mean corpuscular volume (MCV), which is induced by heavy drinking, high acetaldehyde exposure, heavy smoking, and poor nutrition, may be useful in identifying high-risk persons. Endoscopic screening with esophageal iodine staining in Japanese high-risk populations yields very high rates of early ESCC. Treatment of early ESCC by endoscopic mucosectomy has become a widespread practice in Japan and has succeeded in improving the outcome of this high-mortality cancer. New evidence concerning ALDH2/ADH1B/alcohol flushing/MCV-related cancer susceptibility has renewed interest in alcohol and acetaldehyde as important subjects for cancer research and has served as a powerful tool for cancer prevention and cancer screening of Japanese subjects. Review articles on this topic also appeared in the previous issue (Volume 4 Number 3). An editorial related to this article is available at .     

Pathways for the development of multiple epithelial types of intraductal papillary mucinous neoplasm of the pancreas

Journal of Gastroenterology - Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is categorized into four distinct types: the gastric, intestinal, pancreatobiliary, and oncocytic. Each...     

Microbiome composition comparison in oral and atherosclerotic plaque from patients with and without periodontitis

Odontology - There is no conclusive evidence regarding a causal relationship between periodontitis and atherosclerosis. In this study, we examined the microbiome in the oral cavity and atheromatous...     

In vivo pre- and postoperative three-dimensional knee kinematics in unicompartmental knee arthroplasty

Background

Pre- and postoperative knee kinematics in unicompartmental knee arthroplasty (UKA) can be theoretically related to clinical outcome and longevity after UKA with regard to ligament function and the degree of arthritic changes. However, the preoperative knee kinematics of patients indicated for UKA remain to be elucidated, and it is also unclear whether the preoperative kinematics can be maintained by the UKA procedure. The objective of this study was to examine the in vivo pre- and postoperative three-dimensional knee kinematics in UKA while referencing the normal knee kinematics reported in our previous study.

Methods

We analyzed the knee kinematics in 17 knees (14 patients) undergoing UKA via a three-dimensional to two-dimensional registration technique employing femoral condylar translation and femoral axial rotation. The pre- and postoperative knee kinematics during squat motion were evaluated in the same subjects, employing consistent evaluation parameters.

Results

On average, both pre- and postoperative knee kinematics in the range 10–100° of knee flexion demonstrated near-consistent femoral external rotation and anterior translation of the medial condyle and posterior translation of the lateral condyle. However, the mean femoral external rotation angle and the posterior translation of the lateral condyle postoperatively were significantly smaller than the values observed preoperatively.

Discussion

Although the patterns of preoperative knee motion were similar to those seen in normal knees, the magnitude of this motion varied widely between patients, so it was not necessarily representative of normal knees. These variations may be due to the varying degrees of arthritic changes caused by osteoarthritis. Although the patterns of knee kinematics were largely maintained by the UKA procedure, the causes of the significant reductions in the magnitude of motion upon performing the UKA procedure should be investigated in subsequent studies with a larger number of patients.     

Thoracoscopic esophagectomy while in a prone position for esophageal cancer: a preceding anterior approach method

Background

In 2009, the rate of thoracoscopic esophagectomy for esophageal cancer was about 20 % in Japan. This low rate may be due to the difficulty in maintaining a good surgical field and the meticulous procedures that are required. The purpose of this study was to establish and evaluate a new procedure for performing a thoracoscopic esophagectomy while the patient is in a prone position using a preceding anterior approach to make the esophagectomy easier to perform.

Methods

We have performed thoracoscopic esophagectomy using our new procedure in 60 patients with esophageal cancer. Each patient was placed in a prone position and five trocars were inserted; only the left lung was ventilated and a pneumothorax was maintained. The esophagus was mobilized from the anterior structure during the first step and from the posterior structure during the second step. The lymph nodes around the esophagus were also dissected anteriorly and posteriorly. The patients were sequentially divided into two groups and their clinical outcomes were evaluated.

Results

The mean operative time for the thoracoscopic procedure for the latter 30 cases (203 min) was shorter than that for the former 30 cases (260 min) (P = 0.001). Among the 52 cases without pleural adhesion, the mean blood loss in the latter 26 cases (18 mL) was also less than that in the former 26 cases (40 mL) (P = 0.027). There were no conversions to a thoracotomy and no operative deaths in this series. Postoperative complications related to the thoracoscopic procedure occurred in 8 cases (27 %) in the former group and in 4 cases (13 %) in the latter group.

Conclusions

Thoracoscopic esophagectomy with the patient in the prone position using a preceding anterior approach is a safe and feasible procedure. As experience performing the procedure increases, the performance of the procedure stabilizes. This method seems to make the esophagectomy easier to perform.