Light and electron microscopic studies on localization of myoglobin in skeletal muscle cells in neuromuscular diseases

The localizations of myoglobin in skeletal muscle cells of patients with Duchenne muscular dystrophy (DMD), myotonic dystrophy (MyD), and amyotrophic lateral sclerosis (ALS) were studied by immunohistochemistry and immunoelectron microscopy. In normal skeletal muscle cells, myoglobin was localized mainly in the I-band region. In degenerating muscle cells of patients with DMD and MyD, myoglobin was also demonstrated in the distended lumen of the internal membrane system and in the intermyofibrillar space, through which it seemed to pass into the extracellular space. No myoglobin was detected in opaque fibers or in some of small-sized fibers in DMD muscle. In patients with ALS the staining intensities of myoglobin varied in different muscle cells, but myoglobin was restricted to the I-band region in many muscle cells. These findings suggest that changes in the localization of myoglobin in skeletal muscle cell sensitively reflect the pathologic status of muscle cells.     

Increased mucosal ornithine decarboxylase activity in human gastric cancer

The induction of ornithine decarboxylase (ODC), a key enzyme of polyamine biosynthesis, is an early and obligatory event in the tumor-promoting step in animal models. The enzyme activity is also elevated in some human premalignant lesions. We determined the ODC activity in human gastric cancer tissue and in the mucosa of cancer-bearing stomach. We concluded that gastric cancer tissue had significantly elevated ODC levels over those of mucosa (157.8 versus 45.7, respectively; P less than 0.05). Among mucosa of the stomach, that of the pyloric gland had higher ODC activity than that of the fundic gland (42.8 versus 21.6, respectively; P less than 0.05). Moreover, mucosa from the cancer-bearing stomach had high ODC activity compared with gastric mucosa without cancer. ODC activity in cancer tissue and mucosa from cancer-bearing stomach was activated by GTP. In rat experiments, the properties of ODC induced by gastric carcinogen were analyzed. Transiently induced ODC by a single gastric intubation of N-methyl-N'-nitro-N-nitrosoguanidine was not activated by GTP whereas constitutively expressed ODC of N-methyl-N'-nitro-N-nitrosoguanidine-induced cancer-bearing stomach was activated by GTP. These results suggest that some tumor-promoting stimuli may be concerned in human gastric carcinogenesis and that mucosal ODC activity may be a useful marker for assessing the risk of gastric malignancy.     

Allotransplantation of isolated pancreatic islets in diabetic rats. Effect of culture on islet rejection

Reduction of the immunogenicity of the tissue by tissue culture has been a controversial concept in transplantation immunology. In the present study, isolated islets were cultured prior to allotransplantation. The obtained results were compared in comparison with the results of the non-cultured islet allotransplantation group. Two kinds of rats differing from each other in histocompatibility antigen were used. WKA rats ( RT1k ) were donors, and LEJ rats ( RT1j ) recipients. No immunosuppressive agents were given. About 500 isolated islets of the donors were transplanted to the spleen of the recipients with streptozotocin induced diabetes mellitus. Although the mean survival time of non-cultured islet was 12.2 +/- 4.3 days, that of 7-day cultured islet increased significantly to 26.4 +/- 4.8 days. The response of the lymphocytes to the islets was also examined by mixed lymphocyte-islet culture. Response of lymphocytes to non-cultured islet was compared with that of lymphocytes to 7-day cultured islets. The response of lymphocytes to the 7-day cultured islets was significantly decreased. These results suggested that the cultured islet prolongs survival time and islet culture diminish the concentration or availability of stimulatory antigens on the cell surface membranes.     

USE OF SHORT NEEDLE KNIFE FOR ESOPHAGEAL ENDOSCOPIC SUBMUCOSAL DISSECTION

Background: The emergence of endoscopic submucosal dissection (ESD) has enabled en bloc resection of lesions, which were conventionally difficult. However, ESD has problems of technical difficulty and high incidence of complications. In order to improve the procedure of marking and submucosal dissection in the esophagus, we modified and adjusted the standard needle knife to a short needle knife having a tip portion with a projection length of 1.5 mm. Methods: We treated 20 esophageal lesions with ESD using the short needle knife. We marked around the lesion with the short needle knife and performed mucosal incision of the entire circumference with a needle knife and an IT knife, then dissected the submucosal layer with the short needle knife. A Hook knife was also used in situations where muscular layers were located in the front‐view Results: Complete en bloc resection was performed in all 20 cases. The diameter of lesions ranged from 3 to 65 mm (median, 20 mm), and that of resected specimens ranged from 28 to 90 mm (median, 47 mm). Submucosal dissection was completed with the short needle knife alone in 13 cases in 20 (65%), and in seven cases (35%), in combination with so‐called Hook knife. The procedure was complicated in one patient with mediastinal emphysema. Conclusions: The short needle knife proved to be useful and safe in clear marking and submucosal dissection of esophageal lesions. It allows greater flexibility in the angle of insertion, and enables more effective and safer procedures because its full length can be inserted into the submucosa and fixed.     

Respiratory effects of expiratory flow-resistive loading in conscious and anesthetized humans

The response of breathing patterns to increased expiratory resistance is not only of physiologic interest, with respect to the control of breathing, but also of clinical interest because of its clinical relevance to obstructive diseases such as asthma and emphysema. To elucidate the response of breathing patterns to increased expiratory resistance during anesthesia, the respiratory effects of expiratory flow-resistive loading on breathing patterns were studied in 15 conscious and 10 lightly anesthetized subjects. Inspiratory time, expiratory time, respiratory frequency, inspiratory duty cycle, tidal volume, minute ventilation, and mean inspiratory flow rate were determined from a respiratory inductive plethysmograph. End-tidal CO2 was continuously recorded. In awake subjects, respiratory frequency was reduced without change in tidal volume or mean inspiratory flow rate, and minute ventilation was significantly decreased; the synchrony between rib cage and abdomen wall motion was well maintained during the loads. In contrast, in anesthetized subjects, respiratory frequency was reduced with remarkable increases in tidal volume, mean inspiratory flow rate, and minute ventilation, whereas coordination between rib cage and abdomen compartments was disturbed. End-tidal CO2 did not change in conscious subjects, but it increased in anesthetized subjects during the loads. These results indicate that there are differences between conscious and anesthetized subjects in breathing patterns during expiratory loading, and suggest that the ability to coordinate rib cage-abdomen wall motion is easily disturbed during anesthesia in patients with expiratory flow limitation.     

Upper Airway Reflexes during a Combination of Propofol and Fentanyl Anesthesia

Background: The effects of intravenous anesthetics on airway protective reflexes have not been fully explored. The purpose of the present study was to characterize respiratory and laryngeal responses to laryngeal irritation during increasing doses of fentanyl under propofol anesthesia.

Methods: Twenty-two female patients anesthetized with propofol and breathing through the laryngeal mask airway were randomly allocated to three groups: (1) eight patients who received cumulative total doses of 200 [micro sign]g fentanyl given in the form of two doses of 50 [micro sign]g and one dose of 100 [micro sign]g spaced 6 min under mechanical controlled ventilation while end-tidal carbon dioxide tension (PCO2) was maintained at 38 mmHg (fentanyl-controlled ventilation group), (2) eight patients who received cumulative total doses of 200 [micro sign]g fentanyl while breathing spontaneously while end-tidal PCO2 was allowed to increase spontaneously (fentanyl-spontaneous ventilation group), and (3) six spontaneously breathing patients who were anesthetized with propofol alone (propofol group). The laryngeal mucosa of each patient was stimulated by spraying the cord with distilled water, and the evoked responses were assessed by analyzing the respiratory variables and endoscopic images.

Results: Before administration of fentanyl, laryngeal stimulation caused vigorous reflex responses, such as expiration reflex spasmodic panting, cough reflex, and apnea with laryngospasm. Increasing doses of fentanyl reduced the incidences of all these responses, except for apnea with laryngospasm, in a dose-related manner in both the fentanyl-controlled ventilation and the fentanyl-spontaneous ventilation groups. Detailed analysis of endoscopic images revealed several characteristics of laryngeal behavior during the airway reflex responses.     

Sympathectomy does not alter the response of carotid chemoreceptors to hypoxemia during carboxyhemoglobinemia or anemia

We tested the effects of section of the sympathetic innervation to the carotid body on the responses of single carotid chemoreceptor fibers to carboxyhemoglobinemia (40-50%) and anemia (15-20% Hct) at various levels of paO2 (range: 20-450 Torr). Sympathectomy had virtually no effect on the steady-state response curves of carotid chemoreceptors to O2, either in normal cats or in those with reduced oxygen transport due to anemia or carboxyhemoglobinemia.