Biomedical subjects
Publications and source records attributed to C L Wells.
Pure cultures of anaerobic bacteria colonized the gastrointestinal tracts of germfree rats and induced an increase in the cellularity of intestinal tissue.
The capacity of a pure culture of anaerobic intestinal bacteria to influence the host's cellular and humoral immune systems was investigated with germfree, monoassociated, and conventionally reared rats. Monoassociation of germfree rats with Bacteroides fragilis stimulated the production of serum gamma globulin, agglutinating antibodies, and an apparent IgG (immunoelectrophoresis) band. A comparison of the in vitro blastogenic potential of lymphocytes (spleen cells and mesenteric lymph node cells) from germfree, monoassociated, and conventionally reared rats indicated the following: (1) the microbial flora had no obvious effect on the capacity of nonstimulated lymphocytes to incorporate [3H]thymidine; (2) spleen cells from conventionally reared rats responded to phytohemagglutinin, concanavalin A, or pokeweed mitogen better than splenocytes from germfree rats; (3) colonization of germfree rats with Fusobacterium necrophorum increased the responsiveness of splenocytes to photohemagglutinin and concanavalin A; and (4) monoassociation of germfree rats with B. fragilis, but not with F. necrophorum or propionibacterium acnes, increased splenocyte blastogenesis to homologous (i.e., colonizing) bacterial antigens. This study indicated that some intestinal bacteria can modulate the immune status of the host; the extent and nature of this modulation depended on the particular species of colonizing bacteria.
The purpose of this investigation was to observe differences in responses to work in a desert environment among males representing varying levels of acclimatization and physical training. Three groups of subjects were selected: 1) unacclimatized males (UM), VO2max = 46.8 ml . kg-1 . min-1, 2) acclimatized males (AM), VO2max = 49.6 ml . kg-1 . min-1, and 3) acclimatized-fit males (AFM) VO2max = 65.8 ml . kg-1 . min-1. Each subject sat for 40 min and then walked for 40 min at 3.5 miles/h on a grade which represented his 50% VO2max in a neutral indoor environment (WBGT = 18.1 DEGREES C) and in a desert (hot, dry and sunny) environment (WBGT = 29.9 DEGREES C). The UM experienced consistently higher HR during both rest and work in the heat than did the AM. The AFM exhibited lower HR than either AM or UM during both neutral and hot exposures, despite a higher workload. Both groups of acclimatized subjects possessed lower Tre's than the unacclimatized subjects in the heat. The superior fitness of the AFM gave an advantage in terms of increased sweating sensitivity since they had equal or greater SR at lower Tre. It was concluded that a high level of physical training is an additional and important variable in the ability to tolerate work in the desert.
In most studies of physiological responses of men and women to exercise in the heat, the subjects are unacclimatized and the females are unaccustomed to strenuous physical activity. In this investigation, 5 men and 6 women known to be physically active in an outdoor hot-dry environment were studied in a temperate environment (Tdb=23C, WBGT=18C) and in an outdoor desert environment (Tdb=39C, WBGT=29C) during rest and exercise at 50% Vo2max. No differences between the groups occurred in Vo2, HR or Tre in either environment. Of greatest interest was that no differences occurred in evaporative weight losses, sweating rates, or % body weight losses in the heat. It was concluded that (1) women accustomed to exercise in a desert climate are able to substantially increase their sudorific response, and (2) that acclimatized male and female subjects of similar aerobic capacity have comparable responses to rest and exercise in a desert environment.
Propionibacterium acnes (oral and/or parenteral administration) had a modulating effect on antibody-and cell-mediated immune responses of germfree (GF) and monoassociated (MA) rats. In conventionally reared rodents, parenteral injection of killed P. acnes stimulated the splenic plaque-forming cell response to sheep erythrocytes. However, in GF rats and in rats monoassociated with viable P. acnes, parenteral injection of killed P. acnes antigen inhibited the plaque-forming cell response to sheep erythrocytes. When compared with the responses of GF control rats, splenocytes from GF rats parenterally injected with P. acnes antigen had a decreased in vitro blastogenic response to phytohemagglutinin and concanavalin A and an increased blastogenic response to homologous bacterial antigens. Conversely, a parenteral injection of P. acnes antigen into P. acnes MA rats resulted in an increased splenocyte blastogenic response to phytohemagglutinin and concanavalin A but not to homologous (P. acnes) antigens. Thus the presence or absence of intestinal antigenic stimuli (in MA and GF rats) had a modulating effect on the immune response to a parenteral injection of P. acnes antigen.
Nine national and world-class female pentathletes were assessed for body composition, maximal aerobic power (Vo2max), strength, and speed. The subjects averaged 175.4 cm in height, 65.4 kg in weight, 11.0% relative body fat, 45.9 ml kg min-1 in Vo2max, and 8.35 m/sec for maximal running speed. When compared with other athletic females, this group was tall and lean with good, but not exceptional, maximal aerobic power. Group means for one-repetition maximum lifts were 59.7 kg (power clean), 61.5 kg (horizontal bench press), 60.0 kg (pull down), 87.9 kg (squat), 44.9 kg (include bench press), and 36.3 kg (leg curl). Within this elite group the most successful performers were stronger and possessed a greater lean body weight which together suggest the importance of muscle mass for success in the pentathlon.
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Four male and three female physically fit, but untrained subjects performed a treadmill walking task in neutral (25 degrees C), warm (32 degrees C) and hot (40 degrees C) environments. The treadmill grade for each subject was based on 50% VO2 max as determined in a neutral environment. Environmental exposures were 2 h in duration divided into 40 min of rest, work, and recovery. No distinct sexual differences in rectal and skin temperature responses were observed in the three environments. The male subjects had higher heart rates and greater evaporative weight losses during exercise in all environments. The female subjects experienced less severe increases in metabolic requirements during work in the warm and hot environments than the male subjects. The greater percentage of increase in heart rates relative to changes in the metabolic cost of work in the females suggested a greater cardiovascular component of thermal regulation in the female than in the male subjects. The results of this study suggest that physically fit females are capable of working in the heat about as well as males when work load is relative to individual maximal aerobic capacity.
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Male and female "physically active" but untrained subjects walked on a treadmill grade approximating 58% vo2 max as determined in 25 degrees C under three environmental conditions. The environments represented thermal neutrality (Ta = 25 degrees C), a "warm" environment (Ta = 32 degrees C), and a "hot" environment (Ta = 40 degrees C). Relative humidity was 50 to 55%. Exercise vo2 values were significantly influenced by increased environmental temperature. In 40 degrees C, male and female vo2 increased 12% above values in 25 C. VE increase 25% for the female and 32% for the male subjects during exercise in 40 degrees C. In both male and female subjects, true O2 increased slightly in 32 degrees C. but decreased in 40 degrees C from values obtained in 25 degrees C. It was postulated that as Ta increased, blood flow was diverted from metabolically active muscle to nonmetabolically active tissue to enhance heat dissipation via conduction and convection. As a result, oxygen extraction declined, and an increased respiratory drive was incurred.
The long-chain fatty acids extracted from the whole cells of 12 clinically significant species of peptococci and peptostreptococci were characterized by gas-liquid chromatography. The resulting methylated fatty acid profiles (and some unidentified compounds) of 82 strains allowed the 12 species to be separated into four groups. Fifteen strains of Peptostreptococcus anaerobius were placed in group I because they had a unique, prominent compound that occurred in the area where a C8 to C10 fatty acid would be expected. Group II, consisting of Peptostreptococcus intermedius, Peptostreptococcus micros, Peptostreptococcus parvulus, Peptococcus morbillorum, and Peptococcus constellatus, produced C14, C16:1, C18:1, and C18 fatty acids. Peptococcus prevotii, Peptococcus variabilus, Peptococcus magnus, Peptococcus asaccharolyticus, and Peptostreptococcus productus were placed in group III because they contained three to six additional, unidentified compounds that strikingly differentiated them from group II. Peptococcus saccharolyticus was the single species assigned to group IV because it yielded C14, C16, C18:1, C18, and C20 fatty acids and a prominent unidentified peak that occurred between C14 and C16 fatty acids. This study indicated that cellular long-chain fatty acids may be an important tool in clarifying the taxonomy of the peptococci and peptostreptococci.
This study was designed to determine how aging and individual activity patterns affect females' response to maximal exercise. Two treadmill tests for maximal aerobic power (Vo2 max) were administered to 109 females, ages 10 to 68. Subjects were classified as above or below age group means for Vo2 max reported for Scandinavian and Canadian females. Aging effects on cardiovascular and respiratory variables were minimal within each group until age 50, although there was a significant linear decrement in Vo2 max (L/min) with increasing age for the low fitness group. VE max, oxygen debt, postexercise blood lactate, vital capacity, and maximal breathing capacity were also lower for these women. Aging patterns were similar for both groups for Vo2 max ml/kg times min- minus 1 and ml/kg (LBM) times min- minus 1. Responses to an Activity Questionnaire suggested that habitual levels of activity rather than age per se determines levels of Vo2 max for women in the 20-49 age range.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.