Effects of Urethan on Fish Epithelial and Fibroblast Cells in Vitro

The effects of urethan on RTG-2 and FHM cells were studied in vitro, by using the mitotic index, it was determined that 0.3 percent urethan caused an increase in the rate of cell division while higher concentrations (0.6, 0.9, 1.2, and 1.5 percent) caused either a decrease in the rate or a cessation of cell division. Concentrations of urethan higher than 1.5 percent killed the cells. The mitotic index data also indicated that epithelial cells continued to divide at a higher concentration of urethan than did the fibroblast cells. The morphological effects of urethan on the two cell lines were also investigated. These effects included vacuolization of the cytoplasm, lobed and enlarged nuclei, and in some cells the cytoplasm almost completely disappeared and the nucleus developed a thick membrane oround it so that the cells resembled small lymphocytes

Physiological Studies of Heat Stress Acclimation During a Specific Exercise Regimen

Eleven subjects were used to determine if the exercise regimen of racquetball could be used as a heat stress acclimator. Core temperature, skin temperature, sweat production, and weight loss were recorded during a racquetball match. Skin and core temperatures were determined by using thermistors. Sweat was collected with modified stress electrodes. Weight loss was recorded by comparing nude weights at the beginning and end of a match. The results indicated that an hour of strenuous racquetball play caused a significant increase in core temperature with subsequent sweating which resulted in a significant decrease in skin temperature and weight loss. The exercise regimen of racquetball can act as a good heat stress acclimator because it produces sufficiently high levels of hyperthermia

Histological Study of Liver on Channel Catfish, Ictalurus punctatus

Histologically the liver of the channel catfish, Ictalurus punctatus, was found to consist of many lobules. Though not surrounded by a connective tissue sheath as they are in some animals, the lobules were discernable because all the hepatic cells in a particular area radiated from a central vein. Portal triads were scattered throughout the liver. The lobule tissue consisted of radiating cords of cells alternating with sinusoids. Glycogen was condensed into large vacuoles within these cells. Pancreatic tissue was found in the liver, always surrounding a capillary or venule. Morphologically the pancreatic cells were exocrine. Functionally, however, they may be endocrine cells because no ducts were found leading away from them. Connective tissue in the liver was scanty

Relationship Between Physical Conditioning and Plasma High Density Lipoprotein-Cholesterol Concentration

Five subjects (three females and two males) took part in an exercise regimen in order to determine if aerobic exercise results in an increase in high-density lipoprotein-cholesterol levels (HDL-C) in the plasma. The exercise regimen consisted of running three miles a day, five days per week for six months. Running speed was at such a pace that the subjects attained a minimum of 60% of their maximal heart rate reserve (MHRR). Before the training program began the following parameters were measured in all of the subjects: height, weight, percent body fat, maximal oxygen consumption (Vₒ₂ max), vital capacity, resting heart rate, resting blood pressure, HDL-C, plasma triglycerides (TG), and plasma cholesterol (TC). These same measurements were retaken every two months and at the conclusion of the study. The exercise protocol produced significant changes in Vₒ₂ max and resting heart rate. None of the other parameters were significantly changed. The results of this study have shown that aerobic exercise does not cause significant changes in HDL-C levels

Microscopic Anatomy of the Digestive Tract of the White Amur, Ctenopharyngodon idella Val.

The digestive tract of the amur is like that of other vertebrates in that it is composed of four layers: mucosa, submucosa, muscularis externa and serosa. The mucosa is composed of pseudostratified epithelial tissue and an extremely thin lamina propria and muscularis mucosa. Goblet cells are found throughout this layer of the gut, being most numerous In the posterior part. The submucosa is composed of dense irregular connective tissue. The muscularis externa consists of an inner and an outer layer of smooth muscle fibers. However, in the esophageal region this layer also contains some striated muscle. The serosa is composed of a thin layer of dense irregular connective tissue and a single layer of simple squamous mesothelium

Some Physiological and Morphological Adaptations for Underwater Survival in Natrix rhombifera and Elaphe obsoleta

The submergence times of the diamondback water snake (Natrix rhombifera) and black rat snake (Elaphe obsoleta) were compared. Both species could easily survive underwater for periods greater than one hour. Furthermore, there was no difference in time of underwater survival in the two species. Some physiological and morphological parameters which may contribute to the ability of N. rhombifera and E. obsoleta to remain submerged were also examined. E. obsoleta was found to have a greater lung volume and larger and more numerous alveoli than N. rhombifera. Both species demonstrated a bradycardia upon submergence but it was less pronounced than the bradycardia of the true diving animals. It is concluded that N. rhombifera has few physiological adaptations for diving and that some of the physiological attributes for an aquatic existence have already developed in E. obsoleta