Effects of reduced muscle temperature on the oxygen uptake kinetics at the start of exercise

SHIOJIRI, T., SHIBASAKI, M., AOKI, K., KONDO, N. & KOGA, S. 1997. Effects of reduced muscle temperature on the oxygen uptake kinetics at the start of exercise. Acta Physiol Scand 159 , 327–333. Received 25 September 1995, accepted 5 November 1996. ISSN 0001–6772. Laboratory of Exercise and Sports Science, Yokohama City University; Division of Intelligence Science, Graduate School and Technology, Division of Education, Graduate School, Faculty of Human Development, Kobe University; and Applied Physiology Laboratory, Kobe Design University, Japan. The purpose of this study was to examine the effects of reduced muscle temperature (T_m ) on gas exchange kinetics and haemodynamics at the start of exercise. Six male subjects performed moderate cycle exercise under reduced (C) and normal (N) T_m conditions. T_m and rectal temperature were significantly reduced by immersion in cold water (by 6.6 °C and 1.8 °C, respectively). The increases in oxygen uptake (V˙o ₂) and oxygen pulse (V˙o ₂/HR) during phase 1 (abrupt increase after the start of exercise) were significantly lower under C than under N. The time constant for O₂ under C (36.0 ± 7.7 (SD) s) was significantly greater than under N (27.5 ± 4.4 s); however, the time constants of cardiac output under C (38.3 ± 16.6 s) and N (33.7 ± 18.5 s) were similar. These results suggest that the slower V˙o ₂ on-response under reduced T_m conditions is caused by decreased O₂ extraction in working muscle and/or by impairment of oxidative reactions by reduced muscle temperature.     

Improvement of food-sensitive atopic dermatitis accompanied by reduced lymphocyte responses to food antigen following natural measles virus infection

Five patients with atopic dermatitis (AD) who were sensitive to hen's egg were observed before and after natural measles virus infection. Within 4 weeks of natural measles virus infection, the eczematous lesions clearly improved in four of the five patients in whom neither offending foods were eliminated, nor anti-allergic drugs, systemic steroids and steroid ointment administered. This was accompanied by reduced proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA). Another patient showed a transient improvement of AD symptoms, from severe to mild, and thereafter returned to severe accompanied by increased proliferative responses of PBMCs to OA. Radioallergosorbent test (RAST) scores for hen's egg in all five patients did not change in each level in each patient, except the transiently decreased RAST scores for hen's egg in one patient, after the infection. Thus, in patients with AD who are sensitive to food, the improvement of AD symptoms that appeared within 4 weeks of natural measles virus infection was related to reduced proliferative responses of PBMCs to the food antigen following the infection.     

Higher cerebral dysfunction in a case with atypical multiple sclerosis with concentric lesions

Abstract A patient with atypical multiple sclerosis (MS) with clear concentric structure was studied using high field magnetic resonance imaging (MRI). This case was considered to be Balo's concentric sclerosis. Magnetic resonance imaging showed diffuse multiple concentric demyelinating lesions in the bilateral centrum semiovales, which finally regressed with the necrotic lesions remaining when the patient was discharged. During his clinical course, he showed some higher cerebral dysfunctions, such as memory disturbance, constructual apraxia and acalculia. He was treated with glycerin, prednisone and rehabilitation; all of which were effective in his recovery. Over a 4 month period, the patient recoveredclinically, but some intellectual impairment remained.     

Protective effects of a prostaglandin E1 oligomer on taurocholate-induced rat pancreatitis

Effects of prostaglandin E (PGE) on acute pancreatitis have been controversial. This study shows the effects of PGE1 oligomer, MR-356, on trypsin-taurocholate-induced acute pancreatitis in rats. Divided intraperitoneal doses of 0.6 mg/rat were administered, which increased 24 h survival rates when the oligomer was given both at 1 h before and after (group A) and immediately and 3 h after (group B) induction of pancreatitis. In group A MR-356 significantly improved the survival rates at 18 h (94 vs 61%, P < 0.05) and 24 h (68 vs 33%, P < 0.05) when compared with controls. MR-356 improved the survival rates dose-dependently up to 0.6 mg/rat when given by the same protocol of group A. In group B MR-356 also improved the survival rate (72 vs 39%, P < 0.05) only at 24 h, while other parameters failed to improve. The present results suggest that the PGE1 oligomer may play a beneficial role in bile-induced pancreatitis, probably through its proposed effects of stabilization of lysosomal membranes, maintenance of microcirculation and inhibition of protease in the pancreas.     

Differences in the width of the intercellular spaces in the epithelial basal infolding and the renal glomerular filtration site between freeze-substitution and conventional fixation

After aldehyde prefixation, pretreatment with cryoprotectant and subsequent freeze-substitution with OsO₄ in acetone (AC-FS), extensive gap junction-like close membrane appositions are frequently found in the basal infolding of the salivary gland epithelium, although the desmosomal intercellular space had the same width as with conventional electron microscopy. The intercellular space between podocyte pedicles and endothelial cells at the renal glomerular filtration site was narrower by the total width of 2 laminae lucidae following AC-FS than with conventional electron microscopy and was occupied by a homogeneous lamina densa without a lamina lucida, although no marked difference was discernable in the thickness of the lamina densa itself between the 2 preparative procedures. In addition, a decrease in the thickness of the glycocalyx was evident in the intestinal epithelial microvilli following AC-FS. It is thus likely that osmication in acetone at freezing temperatures remove the glycocalyx and related structures to a variable extent, and that this loss is responsible for reducing the intercellular spaces at some of the simple appositions narrower to the dimensions of the gap junction. It is also responsible for disappearance of the lamina lucida of the basement membrane.     

Effects of landiolol on the cardiovascular response during tracheal extubation

The objective of this study was to investigate the effect of landiolol on the cardiovascular responses to emergence from anesthesia and tracheal extubation. Fifty-nine patients without cardiovascular disorders who were scheduled for tympanoplasty were randomly allocated to receive a loading dose of landiolol at 0.125 mg x kg(-1) x min(-1) for 1 min, followed by an infusion at 0.01 mg x kg(-1) x min(-1) (group L1), 0.02 mg x kg(-1) x min(-1) (group L2), 0.03 mg x kg(-1) x min(-1) (group L3), or 0.04 mg x kg(-1) x min(-1) (group L4). At the end of surgery, sevoflurane and nitrous oxide were discontinued, and landiolol was started. The mean arterial pressure (MAP), heart rate (HR), and rate pressure product (RPP) in the four groups were compared before anesthesia induction, just after extubation, 5 min after extubation, 10 min after extubation, and at discharge from the operating room. Just after extubation compared with the baseline, the MAP increased significantly in all groups; the HR increased in groups L1 and L2; and the RPP increased in all groups, except for group L4. Continuous administration of landiolol, at 0.03 or 0.04 mg x kg(-1) x min(-1), may prevent the increases in HR and RPP, respectively, that occur at the emergence from anesthesia and tracheal extubation.