Splenic contraction during breath-hold diving in the Korean ama

Major increases of hemoglobin concentration and hematocrit, possibly secondary to splenic contraction, have been noted during diving in the Weddell seal. We sought to learn whether this component of the diving response could be present in professional human breath-hold divers. Splenic size was measured ultrasonically before and after repetitive breath-hold dives to approximately 6-m depth in ten Korean ama (diving women) and in three Japanese male divers who did not routinely practice breath-hold diving. Venous hemoglobin concentration and hematocrit were measured in nine of the ama and all Japanese divers. In the ama, splenic length and width were reduced after diving (P = 0.0007 and 0.0005, respectively) and calculated splenic volume decreased 19.5 +/- 8.7% (mean +/- SD, P = 0.0002). Hemoglobin concentration and hematocrit increased 9.5 +/- 5.9% (P = 0.0009) and 10.5 +/- 4% (P = 0.0001), respectively. In Japanese male divers, splenic size and hematocrit were unaffected by repetitive breath-hold diving and hemoglobin concentration increased only slightly over baseline (3.0 +/- 0.6%, P = 0.0198). Splenic contraction and increased hematocrit occur during breath-hold diving in the Korean ama.     

Changes in insulation of body tissue and wet suits during underwater exercise at various atmospheric pressures

To clarify the independent changes of insulations of body tissues (Itissue) and wet suit (Isuit) in the wet-suited subject during underwater exercise, overall heat flow from the skin (Htissue) and wet suit (Hsuit) and esophageal (Tes), skin (Tsk), and wet suit temperatures were measured at 1, 2, and 2.5 atmospheres absolute (ATA) at critical water temperature (Tcw). The average Tcw in nine wet-suited men (23-38 yr) was 22.3 +/- 0.2, 26.3 +/- 0.2, and 28.0 +/- 0.4 degrees C (SE) at 1, 2, and 2.5 ATA, respectively. At Tcw of each pressure male volunteers wearing 5-mm neoprene wet suits completed three 2-h experiments while immersed up to the neck. During one experiment the subjects remained at rest, and in the other two they exercised on an underwater ergometer at two different intensities (2 and 3 met). Tes significantly declined (P less than 0.05) over 2 h from 37.1 to 36.5 degrees C during rest in each pressure. The 2-met exercise prevented Tes from falling in all pressures, and the 3-met exercise elevated Tes by 0.2-0.3 degrees C. There was no exercise-dependent difference in Isuit, but a pressure-dependent difference was remarkable. The Itissue at rest was identical for all pressures; however, it progressively decreased as a function of exercise intensity. It is concluded that overall Itissue is entirely determined by work intensity at Tcw, but not by atmospheric pressure. On the contrary, Isuit at Tcw is solely dependent on the pressure, but not on the work intensity.     

Capture myopathy in wild turkeys (Meleagris gallopavo) following trapping, handling and transportation in Colorado

Sixty wild turkeys were necropsied following trapping, transporting and handling during the winters of 1980-1981, 1981-1982, and 1982-1983 in order to determine the incidence of subclinical capture myopathy. Gross lesions characterized by small to large patchy, pale white streaked areas within skeletal muscle were found in 13 of 27 birds trapped with a drop net in the winter of 1982-1983. Microscopic lesions within myocardium characterized by irregular areas of coagulative necrosis, collapse of intercellular stroma and myocardial nuclear proliferation were found in two of 14 birds in 1980-1981, five of 19 birds in 1981-1982 and 11 of 27 birds in 1982-1983. Microscopic lesions within skeletal muscle characterized by rhabdomyolysis were found in 16 of 19 birds in 1981-1982 and 25 of 27 birds in 1982-1983. These findings suggest that wild turkeys are susceptible to capture myopathy and particular caution should be exercised in capturing and handling these birds.     

Energetic cost of foraging in free-diving emperor penguins.

Hypothesizing that emperor penguins (Aptenodytes forsteri) would have higher daily energy expenditures when foraging for their food than when being hand-fed and that the increased expenditure could represent their foraging cost, we measured field metabolic rates (FMR; using doubly labeled water) over 4-d periods when 10 penguins either foraged under sea ice or were not allowed to dive but were fed fish by hand. Surprisingly, penguins did not have higher rates of energy expenditure when they dove and captured their own food than when they did not forage but were given food. Analysis of time-activity and energy budgets indicated that FMR was about 1.7 x BMR (basal metabolic rate) during the 12 h d(-1) that penguins were lying on sea ice. During the remaining 12 h d(-1), which we termed their "foraging period" of the day, the birds were alert and active (standing, preening, walking, and either free diving or being hand-fed), and their FMR was about 4.1 x BMR. This is the lowest cost of foraging estimated to date among the eight penguin species studied. The calculated aerobic diving limit (ADL(C)), determined with the foraging period metabolic rate of 4.1 x BMR and known O(2) stores, was only 2.6 min, which is far less than the 6-min ADL previously measured with postdive lactate analyses in emperors diving under similar conditions. This indicates that calculating ADL(C) from an at-sea or foraging-period metabolic rate in penguins is not appropriate. The relatively low foraging cost for emperor penguins contributes to their relatively low total daily FMR (2.9 x BMR). The allometric relationship for FMR in eight penguin species, including the smallest and largest living representatives, is kJ d(-1)=1,185 kg(0.705).     

Nitrogen tensions in brachial vein blood of Korean ama divers.

Intravascular bubble formation and symptoms of decompression sickness have been reported during repetitive deep breath-hold diving. Therefore we examined the pattern of blood N2 kinetics during and after repetitive breath-hold diving. To study muscle N2 uptake and release, we measured brachial venous N2 partial pressure (PN2) in nine professional Korean breath-hold divers (ama) during a 3-h diving shift at approximately 4 m seawater depth and up to 4 h after diving. PN2 was determined with the manometric Van Slyke method. Diving time and depth were recorded using a backpack computer-assisted dive longer that allowed calculating the surface-to-depth time ratio to derive the effective depth. With the assumption that forearm muscle N2 kinetics follow the general Haldanian principles of compression and decompression, i.e., forearm muscle is a single compartment with a uniform tissue PN2 equal to venous PN2, PN2 data were fitted to monoexponential functions of time. In the early phase of the diving shift, PN2 rapidly increased to 640 Torr (half time = 6 min) and then slowly declined to baseline levels (half time = 36 min) after the work shift. Peak PN2 levels approximated the alveolar PN2 derived from the effective depth. We conclude that forearm muscle N2 kinetics are well described by a Haldanian single-compartment model. Decompression sickness is theoretically possible in the ama; it did not occur because the absolute PN2 remained low due to the shallow working depth of the ama we studied.     

Chemical evolution and the origin of life

This bibliography is the seventeenth annual supplement to the comprehensive bibliography on the same subject which was published in Space Life Sci. 2(1970), 225-295; 3(1972), 293-304; 4(1973), 309-329 and in Origins of Life 5(1974), 505-527; 6(1975), 285-300; 7(1976), 75-85; 8(1977), 59-66; 9(1978), 67-74; 10(1980), 69-87; 10(1980), 379-404; 11(1981), 273-288; 12(1982), 93-118; 13(1983), 61-80; 15(1984), 55-69; 17(1987), 171-184; 17(1987), 185-206.     

Water temperature and intensity of exercise in maintenance of thermal equilibrium

This study examined the thermal and metabolic responses of six men during exercise in water at critical temperature (Tcw, 31.2 +/- 0.5 degrees C), below Tcw (BTcw, 28.8 +/- 0.6 degrees C), at thermoneutrality (Ttn, 34 degrees C), and above Ttn (ATtn, 36 degrees C). At each water temperature (Tw) male volunteers wearing only swimming trunks completed four 1-h experiments while immersed up to the neck. During one experiment, subjects remained at rest (R), and the other three performed leg exercise (LE) at three different intensities (LE-1, 2 MET; LE-2, 3 MET; LE-3, 4 MET). In water warmer than Tcw, there was no difference in metabolic rate (M) during R. The M for each work load was independent of Tw. Esophageal temperature (Tes) remained unchanged during R in water of ATtn (36 degrees C). However, Tes significantly (P less than 0.05) declined over 1 h during R at Ttn (delta Tes = -0.39 degrees C), Tcw (delta Tes = -0.54 degrees C), and BTcw (delta Tes = -0.61 degrees C). All levels of underwater exercise elevated Tes and M compared with R at all Tw. In water colder than Tcw, the ratio of heat loss from limbs compared with the trunk became greater as LE intensity increased, indicating a preferential increase in heat loss from the limbs in cool water. Tissue insulation (Itissue) was lower during LE than at R and was inversely proportional to the increase in LE intensity. A linearly inverse relationship was established between Tw and M in maintaining thermal equilibrium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Finger dexterity, skin temperature, and blood flow during auxiliary heating in the cold.

The primary purpose of the present study was to compare the effectiveness of two forms of hand heating and to discuss specific trends that relate finger dexterity performance to variables such as finger skin temperature (T(fing)), finger blood flow (Q(fing)), forearm skin temperature (T(fsk)), forearm muscle temperature (Tfmus), mean weighted body skin temperature (Tsk), and change in body heat content (DeltaH(b)). These variables along with rate of body heat storage, toe skin temperature, and change in rectal temperature were measured during direct and indirect hand heating. Direct hand heating involved the use of electrically heated gloves to keep the fingers warm (heated gloves condition), whereas indirect hand heating involved warming the fingers indirectly by actively heating the torso with an electrically heated vest (heated vest condition). Seven men (age 35.6 +/- 5.6 yr) were subjected to each method of hand heating while they sat in a chair for 3 h during exposure to -25 degrees C air. Q(fing) was significantly (P < 0.05) higher during the heated vest condition compared with the heated gloves condition (234 +/- 28 and 33 +/- 4 perfusion units, respectively), despite a similar T(fing) (which ranged between 28 and 35 degrees C during the 3-h exposure). Despite the difference in Q(fing), there was no significant difference in finger dexterity performance. Therefore, finger dexterity can be maintained with direct hand heating despite a low Q(fing). DeltaH(b), Tsk, and T(fmus) reached a low of -472 +/- 18 kJ, 28.5 +/- 0.3 degrees C, and 29.8 +/- 0.5 degrees C, respectively, during the heated gloves condition, but the values were not low enough to affect finger dexterity.     

Lake restoration by biomanipulation: Round Lake, Minnesota, the first two years

SUMMARY. 1. Rotenone was applied to Round Lake in the autumn of 1980 in order to eliminate predominantly planktivorous and benthivorous fish. The lake was subsequently restocked with a higher population density of piscivores. The effect of this biomanipulation on the phytoplankton and zooplankton communities and on total nutrient concentrations was monitored at fortnightly intervals during the summers, from May 1980 to September 1982.
2. The abundance of phytoplankton was much lower after biomanipulation and was consistent with observed changes in Secchi disc transparency, total attenuation coefficient and chlorophyll a concentration. Zooplankters were also less abundant in 1981 and 1982 but the decrease in numbers was more than offset by the large increase in the mean sizes of the zooplankters present, so that the estimated grazing pressures in 1981 and 1982 were at least double the 1980 value.
3. Daphnia , rare in 1980, became the dominant genus in 1981 and 1982, and a shift to progressively larger-bodied Daphnia species was observed.
4. Although total nitrogen and total phosphorus levels were generally lower after biomanipulation, their decline could not explain the reduction in phytoplankton abundance which was attributed to the increased grazing pressure. Possible causes of the observed declines in nutrient concentrations are discussed.     

Serological survey for selected diseases in the endangered San Joaquin kit fox (Vulpes macrotis mutica)

Blood from endangered San Joaquin kit foxes (Vulpes macrotis mutica) inhabiting the Elk Hills Naval Petroleum Reserve, Kern County, and the Elkhorn Plain, San Luis Obispo County, California, was collected in 1981, 1982 and 1984 and sera were tested for antibodies against 10 selected pathogens. Proportions of kit fox sera containing antibodies against pathogens were: canine parvovirus, 100% in 1981-1982 and 67% in 1984; infectious canine hepatitis virus, 6% in 1981-1982 and 21% in 1984; canine distemper virus, none in 1981-1982 and 14% in 1984; Francisella tularensis, 8% in 1981-1982 and 31% in 1984; Brucella abortus, 8% in 1981-1982 and 3% in 1984; Brucella canis, 14% in 1981-1982 and none in 1984; Toxoplasma gondii, 6% in 1981-1982; Coccidioides immitis, 3% in 1981-1982; and Yersinia pestis and Leptospira interrogans serotypes canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona, none in 1981-1982. Although antibodies against selected pathogens were present, no clinical indications of disease were observed in these fox populations.     

Lyme disease in Wisconsin: epidemiologic, clinical, serologic, and entomologic findings

In 1980-82, 80 individuals (71 Wisconsin residents) had confirmed Lyme disease (LD-c) reported; 39 additional patients had probable or possible LD. All cases of LD-c occurred during May-November; 73 percent occurred during June-July; 54 (68 percent) occurred in males. The mean age was 38.7 years (range, 7-77 years). Among LD-c patients, likely exposure to the presumed vector Ixodes dammini (ID) occurred in 22 different Wisconsin counties. Antibodies to the ID spirochete that causes LD occurred in 33 of 49 LD-c cases versus 0 of 18 in ill controls (p less than .001) and in 13 of 26 LD-c cases treated with penicillin or tetracycline versus 16 of 19 LD-c cases not treated. Early antibiotic therapy appears to blunt the antibody response to the ID spirochete. Regional tick surveys conducted in Wisconsin during each November in 1979-82 have demonstrated regions of greater density of ID. Utilizing comparable tick collection in these surveys, increases were noted in the percentage of deer with ID from 24 percent (31/128) in 1979 to 38 percent (58/152) in 1981, in the standardized mean value of ID/deer from 1.0 in 1979 to 2.2 in 1981, in the percentage of ID of the total ticks collected from 13 percent in 1979 to 71 percent in 1981, or in the ratio of ID to Dermacentor albipictus ticks from 0.14 in 1979 to 2.44 in 1981. However, a reduction in the density of ID/deer was noted generally throughout Wisconsin in 1982 when compared to 1981. LD is widespread in Wisconsin, with ecologic and clinical features similar to those occurring along the eastern seaboard.     

Effect ofAzospirillum inoculation on nitrogen fixation and growth of several winter legumes

Summary Inoculation of naturally nodulatedPisum sativum L. (garden pea) withAzospirillum in the greenhouse caused a significant increase in nodule numbers above controls. Field inoculation of garden peas in the winter 1981–1982 andCicer arietinum L. (chick pea), in winter 1982–1983, withAzospirillum one week after plant emergence, produced a significant increase in seed yield, but did not affect plant dry matter yield. ForVicia sativa L. (vetch) grown in soil in the greenhouse and in the field for forage, winter 1980–1981, inoculation significantly increased dry matter yield, %N, N-content, and acetylene reduction (nitrogen fixation) activity. InHedysarum coronarium L. (sulla clover), winter 1981–1982, inoculated with both its specificRhizobium (by the slurry method) andAzospirillum, 7 days after emergence, there was an increase in acetylene reduction above controls inoculated withRhizobium alone. These results suggest that it is possible, under conditions tested in this work, to increase nodulation, nitrogen fixation, and crop yields of winter legumes by inoculation withAzospirillum.     

Variation in energy expenditure among black-legged kittiwakes: effects of activity-specific metabolic rates and activity budgets

We sought to determine the effect of variation in time-activity budgets (TABs) and foraging behavior on energy expenditure rates of parent black-legged kittiwakes (Rissa tridactyla). We quantified TABs using direct observations of radio-tagged adults and simultaneously measured field metabolic rates (FMR) of these same individuals (n=20) using the doubly labeled water technique. Estimated metabolic rates of kittiwakes attending their brood at the nest or loafing near the colony were similar (ca. 1.3 x basal metabolic rate [BMR]), although loafing during foraging trips was more costly (2.9 x BMR). Metabolic rates during commuting flight (7.3 x BMR) and prey-searching flight (6.2 x BMR) were similar, while metabolic rates during plunge diving were much higher (ca. 47 x BMR). The proportion of the measurement interval spent foraging had a positive effect on FMR (R2=0.68), while the combined proportion of time engaged in nest attendance and loafing near the colony had a negative effect on FMR (R2=0.72). Thus, more than two-thirds of the variation in kittiwake FMR could be explained by the allocation of time among various activities. The high energetic cost of plunge diving relative to straight flight and searching flight suggests that kittiwakes can optimize their foraging strategy under conditions of low food availability by commuting long distances to feed in areas where gross foraging efficiency is high.     

Is there evidence for an age-related reduction in metabolic rate?

To determinewhether the age-related reduction in basal metabolic rate (BMR) isexplained by a quantitative and/or qualitative change in thecomponents of lean tissue, we conducted a cross-sectional study ingroups of young (n = 38, 18-35yr) and older (n = 24, 50-77 yr)healthy individuals. BMR was measured by indirect calorimetry. Bodycomposition was obtained by using dual-energy X-ray absorptiometry (DEXA), which permitted four compartments to be quantified [bone mineral mass, fat mass (FM), appendicular lean tissue mass(A_LTM), and nonappendicular leantissue mass (NA_LTM)].Absolute BMR and A_LTM were lower,whereas FM was significantly higher in the older, compared with young,subjects. BMR, adjusted for differences in FM,A_LTM, andNA_LTM, was significantly lower inthe older subjects by 644 kJ/day. In separate regression analyses ofBMR on body compartments, older subjects had significantly lowerregression coefficients for A_LTMand NA_LTM, compared with youngsubjects. Hence, the age-related decline in BMR is partly explained bya reduction in the quantity, as well as the metabolic activity, ofDEXA-derived lean tissue components.

     

Metabolic and ventilatory acclimatization to cold stress in house sparrows (Passer domesticus)

Passerines that overwinter in temperate climates undergo seasonal acclimatization that is characterized by metabolic adjustments that may include increased basal metabolic rate (BMR) and cold-induced summit metabolism (M(sum)) in winter relative to summer. Metabolic changes must be supported by equivalent changes in oxygen transport. While much is known about the morphology of the avian respiratory system, little is known about respiratory function under extreme cold stress. We examined seasonal variation in BMR, M(sum), and ventilation in seasonally acclimatized house sparrows from Wisconsin. BMR and M(sum) increased significantly in winter compared with summer. In winter, BMR increased 64%, and M(sum) increased 29% over summer values. The 64% increase in winter BMR is the highest recorded for birds. Metabolic expansibility (M(sum)/BMR) was 9.0 in summer and 6.9 in winter birds. The metabolic expansibility of 9.0 in summer is the highest yet recorded for birds. Ventilatory accommodation under helox cold stress was due to changes in breathing frequency (f), tidal volume, and oxygen extraction efficiency in both seasons. However, the only significant difference between summer and winter ventilation measures in helox cold stress was f. Mean f in helox cold stress for winter birds was 1.23 times summer values.     

Involvement of basal metabolic rate in determination of type of cold tolerance

This study aimed to assess the relationship between basal metabolic rate (BMR) and metabolic heat production, and to clarify the involvement of BMR in determining the phenotype of cold tolerance. Measurements of BMR, maximum oxygen uptake, and cold exposure test were conducted on ten males. In the cold exposure test, rectal (T(rec)) and mean skin temperatures (T(ms)), oxygen uptake, and blood flow at forearm (BF(arm)) were measured during exposure to cold (10 degrees C) for 90 min. Significant correlations were observed between BMR and increasing rate of oxygen uptake, as well as between decreasing rate of BF(arm) and increasing rate of oxygen uptake at the end of cold exposure. These findings suggested that individuals with a lower BMR were required to increase their metabolic heat production during cold exposure, and that those with a higher BMR were able to moderate increased metabolic heat production during cold exposure because they were able to reduce heat loss. This study showed that BMR is an important factor in determining the phenotype of cold tolerance, and that individuals with a low BMR showed calorigenic-type cold adaptation, whereas subjects with a high BMR exhibited adiabatic-type cold adaptation by peripheral vasoconstriction.     

The human spleen as an erythrocyte reservoir in diving-related interventions.

Twelve subjects without and ten subjects with diving experience performed short diving-related interventions. After labeling of erythrocytes, scintigraphic measurements were continuously performed during these interventions. All interventions elicited a graduated and reproducible splenic contraction, depending on the type, severity, and duration of the interventions. The splenic contraction varied between approximately 10% for "apnea" (breath holding for 30 s) and "cold clothes" (cold and wet clothes applied on the face with no breath holding for 30 s) and approximately 30-40% for "simulated diving" (simulated breath-hold diving for 30 s), "maximal apnea" (breath holding for maximal duration), and "maximal simulated diving" (simulated breath-hold diving for maximal duration). The strongest interventions (simulated diving, maximal apnea, and maximal simulated diving) elicited modest but significant increases in hemoglobin concentration (0.1-0.3 mmol/l) and hematocrit (0.3-1%). By an indirect method, the splenic venous hematocrit was calculated to 79%. No major differences were observed between the two groups. The splenic contraction should, therefore, be included in the diving response on equal terms with bradycardia, decreased peripheral blood flow, and increased blood pressure.     

长爪沙鼠的代谢率与器官的关系

我们测定了野生长爪沙鼠（Meriones unguiculatus)的基础代谢率和冷诱导的最大代谢率,分析了动物体内11种器官或组织的大小与代谢率的关系。长爪沙鼠的基础代谢率为118.10mlO2/h,最大代谢率为659.83mlO2/h。经过残差分析表明,基础代谢率并不与任何一种器官或组织相关,而最大代谢率与小肠湿重（n=20,r=-0.478,P=0.033)和消化道全长（n=20,r=-0.487,P=0.030)显著相关,表明体内器官重量的差别并不是造成种内基础代谢率差别的原因;体内存在着与最大代谢率相关的“代谢机器”,消化系统（特别是小肠）是这一代谢机器的重要组成部分,但代谢机器的大小并不能通过基础代谢率反映出来。基础代谢率与最大代谢率不相关,因此不支持“较高的基础代谢率能够产生较高的非基础代谢率（最大代谢率等）”的假设。     

Place of muscular exercise test in screening in asymptomatic smokers

The diagnosis of smoking-related chronic obstructive pulmonary disease (COPD) is often made too late. Could the study of breathing pattern during exercise testing help in earlier detection. In order to test this hypothesis, we studied 34 asymptomatic smokers (S) compared to 55 nonsmoking controls (NS). The subjects, divided into 3 age groups (30-60 yr), were comparable in terms of anthropometric and spirometric characteristics. The smokers from 30-50 yr had a lower VO2max than the controls (p less than 0.01) whereas the older smokers (50-60 yr) had a VO2max comparable to that of the controls. The study of breathing pattern indicated rapid, shallow breathing by all smokers. Thus exercise testing, and the abnormalities observed in breathing pattern, would seem to help in early detection of COPD in asymptomatic smokers.