Species variation in osmotic, cryoprotectant, and cooling rate tolerance in poultry, eagle, and peregrine falcon spermatozoa

Potential factors influencing spermatozoa survival to cryopreservation and thawing were analyzed across a range of the following avian species: domestic chicken (Gallus domesticus), domestic turkey (Meleagris gallopavo), golden eagle (Aquila chrysaetos), Bonelli's eagle (Hieraaetus fasciatus), imperial eagle (Aquila adalberti), and peregrine falcon (Falco peregrinus). Studies focused on spermatozoa tolerance to the following: 1) osmotic stress, 2) different extracellular concentrations of the cryoprotectant dimethylacetamide (DMA), 3) equilibration times of 1 versus 4 h, 4) equilibration temperature of 4 versus 21 degrees C, and 5) rapid versus slow cooling before cryopreservation and standard thawing. Sperm viability was assessed with the live/dead stain (SYBR-14/propidium iodine). Sperm viability at osmolalities >/=800 mOsm was higher (P: < 0.05) in raptor than poultry semen. Return to isotonicity after exposure to hypertonicity (3000 mOsm) decreased (P: < 0.05) number of viable spermatozoa in chicken, turkey, and golden and Bonelli's eagle spermatozoa but not in imperial eagle or peregrine falcon spermatozoa. Differences were found in spermatozoa resistance to hypotonic conditions, with eagle species demonstrating the most tolerance. Semen, equilibrated for 1 h (4 degrees C) in diluent containing DMA (> or =2.06 M), experienced decreased (P: < 0. 05) spermatozoa survival in all species, except the golden eagle and peregrine falcon. Number of surviving spermatozoa diminished progressively with increasing DMA concentrations in all species. Increased equilibration temperature (from 4 to 21 degrees C) markedly reduced (P: < 0.05) spermatozoa survival in all species except the Bonelli's eagle and turkey. Rapid cooling was detrimental (P: < 0.05) to spermatozoa from all species except the imperial eagle and the chicken. These results demonstrate that avian spermatozoa differ remarkably in response to osmotic changes, DMA concentrations, equilibration time, temperature, and survival after fast or slow freezing. These differences emphasize the need for species-specific studies in the development and enhancement of assisted breeding for poultry and endangered species.     

Comparison of estrogen concentrations, estrone sulfatase and aromatase activities in normal, and in cancerous, human breast tissues

In the present study, the concentrations of estrone (E(1)), estradiol (E(2)) and their sulfates (E(1)S and E(2)S), as well as the sulfatase and aromatase activities, were evaluated in post-menopausal patients with breast cancer. Comparative studies of the evaluation of these parameters were carried out in (a) tumor tissue, (b) areas surrounding the tumor, and (c) areas distant from the tumor (glandular tissue) which were considered as normal tissue. The levels (in pm/g; mean +/- SEM) were: for E(1) in the (a) area: 320+/-95; in (b): 232+/-86; and in (c): 203+/-71; for E(2) in the (a) area: 388+/-106; in (b): 224+/-48; and in (c): 172+/-80; for E(1)S in the (a) area: 454+/-110; in (b): 259+/-90; and in (c): 237+/-65; for E(2)S in the (a) area:318+/-67; in (b): 261+/-72; and in (c): 232+/-75, respectively. The values of E(1)S and E(2) were significantly higher in the tumor tissue than in the area considered as normal. In all the tissues studied, the sulfatase activity was much higher than aromatase (130-200). In addition, the sulfatase levels were significantly higher in the peripheral and in the tumor tissue than in the area considered as normal. The levels of aromatase were significantly higher in tumoral than in normal tissue. The present data extend the "intracrine concept" for breast cancer tumors. The physiopathology and clinical significance as promoter parameters in breast cancer is to be explored.     

Pollen,ovules, and pollination in pea: Success,failure, and resilience in heat

Field pea (Pisum sativum), a major grain legume crop, is autogamous and adapted to temperate climates. The objectives of this study were to investigate effects of high temperature stress on stamen chemical composition, anther dehiscence, pollen viability, pollen interactions with pistil and ovules, and ovule growth and viability. Two cultivars (“CDC Golden” and “CDC Sage”) were exposed to 24/18°C (day/night) continually or to 35/18°C for 4 or 7 days. Heat stress altered stamen chemical composition, with lipid composition of “CDC Sage” being more stable compared with “CDC Golden.” Heat stress reduced pollen viability and the proportion of ovules that received a pollen tube. After 4 days at 35°C, pollen viability in flower buds decreased in “CDC Golden,” but not in “CDC Sage.” After 7 days, partial to full failure of anthers to dehisce resulted in subnormal pollen loads on stigmas. Although growth (ovule size) of fertilized ovules was stimulated by 35°C, heat stress tended to decrease ovule viability. Pollen appears susceptible to stress, but not many grains are needed for successful fertilization. Ovule fertilization and embryos are less susceptible to heat, but further research is warranted to link the exact degree of resilience to stress intensity.     

Selenium,cadmium, lead,and mercury concentrations in human breast milk,in placenta,maternal blood,and the blood of the newborn

The concentrations of the trace elements Cd, Hg, Pb, and Se during the perinatal period in human placenta and in the blood of the mother and the newborn (cord blood) were determined. Breast milk (colostrum and mature milk) was also included to permit correlations between the different compartments. For Cd, a placental barrier exists, in accord with previous observations. For Pb, a strong correlation between the concentrations in the blood of the mother and of the newborn was found. The concentration of Hg was in most cases below low the detection limit. Its concentration in colostrum was higher than in the mature milk. The results for Se reflect the knowledge about an essential trace element. Strong positive correlations were noted between maternal blood and cord blood and maternal milk. Anodic stripping voltammetry (DPASV) was used for the determination of Cd and Pb, cold vapor AAS (CVAAS) for the determination of Hg, and instrumental neutron activation analysis (INAA) for the determination of Se.     

Molecular characterizations of Cryptosporidium, Giardia, and Enterocytozoon in humans in Kaduna State, Nigeria

The use of molecular diagnostic tools in epidemiological investigations of Cryptosporidium, Giardia, and Enterocytozoon has provided new insights into their diversity and transmission pathways. In this study, 157 stool specimens from 2-month to 70-year-old patients were collected, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the small subunit (SSU) rRNA gene was used to detect and differentiate Cryptosporidium species, and DNA sequence analysis of the 60 kDa glycoprotein (gp60) gene was used to subtype Cryptosporidium hominis and Cryptosporidium parvum. Giardia duodenalis, and Enterocytozoon bieneusi in the specimens were detected using PCR and sequence analysis of the triosephosphate isomerase (tpi) gene and internal transcribed spacer (ITS), respectively. C. hominis and C. parvum were found in two (1.3%) and one (0.6%) specimen respectively, comprising of Ia and IIe (with 8 nucleotide substitutions) subtype families. The G. duodenalis A2 subtype was detected in five (3.2%) specimens, while four genotypes of E. bieneusi, namely A, type IV, D and WL7 were found in 10 (6.4%) specimens. Children aged two years or younger had the highest occurrence of Cryptosporidium (4.4%) and Enterocytozoon (13.0%) while children of 6 to 17 years had the highest Giardia infection rate (40.0%). No Cryptosporidium, Giardia, and Enterocytozoon were detected in patients older than 60 years. Enterocytozoon had high infection rates in both HIV-positive (3.3%) and HIV-negative (8.3%) patients. Results of the study suggest that anthroponotic transmission may be important in the transmission of Cryptosporidium spp. and G. duodenalis while zoonotic transmissions may also play a role in the transmission of E. bieneusi in humans in Kaduna State, Nigeria.     

Cadmium transport, resistance, and toxicity in bacteria, algae, and fungi

Cadmium is an important environmental pollutant and a potent toxicant to bacteria, algae, and fungi. Mechanisms of Cd toxicity and resistance are variable, depending on the organism. It is very clear that the form of the metal and the environment it is studied in, play an important role in how Cd exerts its effect and how the organism(s) responds. A wide range of Cd concentrations have been used to designate resistance in organisms. To date, no concentration has been specified that is applicable to all species studied under standardized conditions. Cadmium exerts its toxic effect(s) over a wide range of concentrations. In most cases, algae and cyanobacteria are the most sensitive organisms, whereas bacteria and fungi appear to be more resistant. In some bacteria, plasmid-encoded resistance can lead to reduced Cd2+ uptake. However, some Gram-negative bacteria without plasmids are just as resistant to Cd as are bacteria containing plasmids encoding for Cd resistance. According to Silver and Misra (1984), there is no evidence for enzymatic or chemical transformations associated with Cd resistance. Insufficient information is available on the genetics of Cd uptake and resistance in cyanobacteria and algae. Mechanisms remain largely unknown at this point in time. Cadmium is toxic to these organisms, causing severe inhibition of such physiological processes as growth, photosynthesis, and nitrogen fixation at concentrations less than 2 ppm, and often in the ppb range (Tables 2 and 3). Cadmium also causes pronounced morphological aberrations in these organisms, which are probably related to deleterious effects on cell division. This may be direct or indirect, as a result of Cd effects on protein synthesis and cellular organelles such as mitochondria and chloroplasts. Cadmium is accumulated internally in algae (Table 4) as a result of a two-phase uptake process. The first phase involves a rapid physicochemical adsorption of Cd onto cell wall binding sites, which are probably proteins and (or) polysaccharides. This is followed by a lag period and then a slow, steady intracellular uptake. This latter phase is energy dependent and may involve transport systems used to accumulate other divalent cations, such as Mn2+ and Ca2+. Some data indicate that Cd resistance, and possibly uptake, in algae and cyanobacteria is controlled by a plasmid-encoded gene(s). Although considerable information is available on Cd toxicity to, and uptake in fungi, further work is clearly needed in several areas. There is little information about Cd uptake by filamentous fungi, and even in yeasts, information on the specificity, kinetics, and mechanisms of Cd uptake is limited.(ABSTRACT TRUNCATED AT 400 WORDS)     

Stress,anxiety, and depression in hospital consultants,general practitioners,and senior health service managers.

OBJECTIVE--To study stress, anxiety, and depression in a group of senior health service staff. DESIGN--Postal survey. SUBJECTS--81 hospital consultants, 322 general practitioners, and 121 senior hospital managers (total 524). MAIN OUTCOME MEASURES--Scores on the general health questionnaire and the hospital anxiety and depression scale. RESULTS--Sixty five (80%) consultants, 257 (80%) general practitioners, and 67 (56%) managers replied. Of all 389 subjects, 183 (47%) scored positively on the general health questionnaire, indicating high levels of stress. From scores on the hospital anxiety and depression scale only 178 (46%) would be regarded as free from anxiety, with 100 (25%) scoring as borderline cases and 111 (29%) likely to be experiencing clinically measurable symptoms. The findings for depression were also of some concern, especially for general practitioners, with 69 (27%) scoring as borderline or likely to be depressed. General practitioners were more likely to be depressed than managers (69 (27%) v 4 (6%) scored > or = 8 on hospital anxiety and depression scale-D; P = 0.004) with no significant difference between general practitioners and consultants. General practitioners were significantly more likely to show suicidal thinking than were consultants (36 (14%) v 3 (5%); P = 0.04) but not managers (9 (13%)). No significant difference could be found between the three groups on any other measure. CONCLUSIONS--The levels of stress, anxiety, and depression in senior doctors and managers in the NHS seem to be high and perhaps higher than expected.     

Carnitine,carnitine acetyltransferase,and glutathione in Alzheimer brain

Glutathione and total carnitine (i.e., free carnitine plus acid-soluble carnitine esters) were measured in an affected (superior frontal gyrus; SFG) and unaffected (cerebellum: CBL) region of Alzheimer disease (AD) and control brains. Average glutathione content in AD SFG (n=13) and AD CBL (n=7) (7.9±2.1 and 11.9±4.0 nmol/mg protein, respectively (mean ±S.D.)) was similar to that in control SFG (n=13) and CBL (n=6) (7.7±2.0 and 11.6±2.6 nmol/mg protein, respectively). However, glutathione increased significantly with age in AD brain (p=0.003) but not in control brain. Average total carnitine in AD SFG (84±47 pmol/mg protein; n=10) and AD CBL (108±86 pmol/mg protein; n=7) was not significantly different from that in the corresponding regions of control brain (148±97 (n=10) and 144±107 (n=6) pmol/mg protein, respectively). However, a significant decline of total carnitine with age in both regions was noted for AD brain, but not for control brain. Carnitine acetyltransferase activity in the AD SFG (n=13) was not significantly different from that of control SFG (n=13) (1.83±1.05 and 2.04±0.82 nmol/min/mg protein, respectively). However, carnitine acetyltransferase activity of AD CBL (n=7) was significantly lower than that of control CBL (n=6) (1.33±0.88 versus 2.26±0.66 nmol/min/mg protein; p=0.05).     

Big-game,small-game,and gamebird hunting in New Zealand: Hunting effort,harvest, and expenditure in 1988

Abstract

A postal survey of 8639 licensed firearm owners in 1989 indicated that an estimated 117 200 ± 6300 New Zealanders (3.5% of the total population) did some hunting in 1988. An estimated 33 100 former hunters did not hunt in 1988 but thought it likely that they would hunt again in future. The survey provided useful estimates of 1988 national totals for hunting effort (4.4 million hunter days), gross expenditure ($NZ100 million), and harvest (6.5 million animals).

Small-game hunting dominated, involving 81% of hunters, 59% of total hunting effort, and 86% of total numerical harvest: rabbits (Oryctolagus cuniculus) and possums (Trichosurus vulpecula) each comprised 40% of the national bag. Gamebird hunting involved 48% of hunters, 19% of effort, and 11% of total harvest: ducks comprised 73% of the gamebird harvest. Although big-game hunting attracted the fewest hunters (42%) it ranked second for hunting effort (21%). Big game formed 3% of the total numerical harvest: pigs (Sus scrofa), goats (Capra hircus), and red deer (Cervus elaphus scoticus) were the most commonly taken. Big-game were estimated to comprise 49% of total harvest biomass, followed by small-game (47%), and gamebirds (4%). Most deer (nearly 60%) were taken for recreation, with helicopter-based hunting accounting for only one-third the total deer harvest.

A quarter of those people hunting in 1988 hunted on five or fewer days that year, and a relatively small group of mainly professional hunters accounted for a disproportionately large share of the overall harvest Hunters reported spending an average of $851 each on hunting in 1988. Expenditure on big-game comprised 44% of the total, small-game 23%, and gamebirds 33%. Expenditure per animal harvested or per day hunted was greater for big-game animals (other than goats) than for gamebirds, which were more expensive to hunt than small-game. Total hunting effort was inversely related to the average expenditure per animal harvested, regardless of the type of game.     

Energy expenditure, insulin, and VLDL-triglyceride production in humans

Hypertriglyceridemia is considered a cardiovascular risk factor in diabetic and nondiabetic subjects. In this study, we aimed to determine potential regulators of very low density lipoprotein-triglyceride (TG) production. VLDL-TG kinetics were measured in 13 men and 12 women [body mass index [mean (range)]: 24.8 (20.2-35.6) kg/m(2)]. VLDL-TG production was assessed from the plasma decay of a bolus injection of ex vivo labeled VLDL particles ([1-(14)C]triolein-VLDL-TG). Similar VLDL-TG production (micromol/min) was found in men and women. VLDL-TG production was not significantly correlated with palmitate flux ([9,10-(3)H]palmitate) (r = 0.09, P = 0.67) or palmitate concentration (r = -0.29, P = 0.2) but was correlated significantly with fasting insulin concentration (r = 0.46, P < 0.05) and resting energy expenditure (REE) (r = 0.45, P < 0.05). The latter correlation improved when adjusted for sex. The best multivariate model with VLDL-TG production as the dependent variable and REE, body composition, hormones, and substrate levels as independent variables included fasting insulin (P = 0.02) and REE (P = 0.02) (r(2) = 0.32, P < 0.001). We conclude that VLDL kinetics are similar in men and women and that REE and plasma insulin are significant independent predictors of VLDL-TG production. FFA availability and body fat distribution are unrelated to VLDL production. We suggest that REE plays a greater role in VLDL-TG production than previously anticipated. REE and insulin should be taken into account when VLDL-TG production comparisons between groups are made.     

Metrology in physics,chemistry, and biology

The association of physics and chemistry with metrology (the science of measurements) is well documented. For practical purposes, basic metrological measurements in physics are governed by two components, namely, the measure (i.e., the unit of measurement) and the measurand (i.e., the entity measured), which fully account for the integrity of a measurement process. In simple words, in the case of measuring the length of a room (the measurand), the SI unit meter (the measure) provides a direct answer sustained by metrological concepts. Metrology in chemistry, as observed through physical chemistry (measures used to express molar relationships, volume, pressure, temperature, surface tension, among others) follows the same principles of metrology as in physics. The same basis percolates to classical analytical chemistry (gravimetry for preparing high-purity standards, related definitive analytical techniques, among others). However, certain transition takes place in extending the metrological principles to chemical measurements in complex chemical matrices (e.g., food samples), as it adds a third component, namely, indirect measurements (e.g., AAS determination of Zn in foods). This is a practice frequently used in field assays, and calls for additional steps to account for traceability of such chemical measurements for safeguarding reliability concerns. Hence, the assessment that chemical metrology is still evolving.     

Capture,Movement, Trade,and Consumption of Mammals in Madagascar

Wild meat trade constitutes a threat to many animal species. Understanding the commodity chain of wild animals (hunting, transportation, trade, consumption) can help target conservation initiatives. Wild meat commodity chain research has focused on the formal trade and less on informal enterprises, although informal enterprises contribute to a large portion of the wild meat trade in sub-Saharan Africa. We aimed to provide a more comprehensive understanding of the formal and informal components of these commodity chains by focusing on the mammalian wild meat trade in Madagascar. Our objectives were to: (1) identify hunting strategies used to capture different wild mammals; (2) analyze patterns of movement of wild meat from the capture location to the final consumer; (3) examine wild meat prices, volumes, and venues of sale; and (4) estimate the volume of wild meat consumption. Data were collected in May-August 2013 using semi-structured interviews with consumers (n = 1343 households, 21 towns), meat-sellers (n = 520 restaurants, open-air markets stalls, and supermarkets, 9 towns), and drivers of inter-city transit vehicles (n = 61, 5 towns). We found that: (1) a wide range of hunting methods were used, though prevalence of use differed by animal group; (2) wild meat was transported distances of up to 166 km to consumers, though some animal groups were hunted locally (<10 km) in rural areas; (3) most wild meat was procured from free sources (hunting, gifts), though urban respondents who consumed bats and wild pigs were more likely to purchase those meats; and (4) wild meat was consumed at lower rates than domestic meat, though urban respondents consumed wild meat twice as much per year compared to rural respondents. Apart from the hunting stage, the consumption and trade of wild meat in Madagascar is also likely more formalized than previously thought.     

Lung volume, chest size, and hematological variation in low-, medium-, and high-altitude central Asian populations

To evaluate adaptive responses to high-altitude environment, we examined three groups of healthy adult males from Central Asia: 94 high-altitude (HA) Kirghiz subjects (3,200 m above sea level); 114 middle-altitude (MA) Kazakh subjects (2,100 m), and 90 low-altitude (LA) Kirghiz subjects (900 m). Data on chest size (chest perimeter and chest diameter), lung volume (forced expiratory volume (FEV) and forced expiratory volume in 1 sec (FEV1)), and hematological parameters (hemoglobin, erythrocytes, hematocrit, and SaO(2)) are discussed. The results show that 1) chest shape is less flat in the samples living at higher altitude. In the HA sample, chest perimeter is lower but chest excursion is high. 2) In the highlanders, forced vital capacity (FVC) and FEV1 are no higher than in the other samples, even when corrected for stature and body weight. The negative correlation between FVC-FEV1 and age decreases with increasing altitude. 3) The HA and MA samples have higher values of hemoglobin, erythrocytes, and hematocrit. The HA sample has lower SaO(2) and higher arterial oxygen content than the LA sample. No association between hematocrit and age was detected in the four samples. The results indicate that the high-altitude Kirghiz present features of developmental acclimatization to hypobaric hypoxia which are also strongly influenced by other major high-altitude environmental stresses.     

Ethics, Economics, and Aids in Africa

AIDS in the Twenty-First Century: Disease and Globalization , by Tony Barnett and Alan Whiteside. New York: Palgrave Macmillan. 2002. 416 pp. US$19.95 (paperback)
The Moral Economy of AIDS in South Africa , by Nicoli Nattrass. Cambridge, UK: Cambridge University Press. 2004. 222 pp. US$30.00 (paperback)     

Serum protein binding characteristics of cyproterone acetate, gestodene, levonorgestrel and norethisterone in rat, rabbit, dog, monkey and man

Protein binding characteristics including percentage of total binding, total binding capacity (pmol/mg protein), degree of specific binding, competition with dihydrotestosterone (DHT) and estradiol (E2) binding sites and dissociation constants (Kd) of low and high affinity binding sites were investigated for the progestins cyproterone acetate (CPA), gestodene (G), norethisterone (NET) and levonorgestrel (LN) in serum or plasma pools from man and four laboratory animal species (rat, rabbit, dog and monkey). Serum pools from animals were constructed from samples obtained either prior to or 1 day after pretreatment with ethinyl estradiol (EE2) (5 micrograms/kg/day for 7 days). Human plasma pools differed by SHBG levels (normal/induced). All serum pools were characterized by protein content and distribution. Equilibrium dialysis or dextran-coated charcoal (DCC) methods were used to separate bound and free steroids labelled with tritium. All progestins were highly (greater than 80%) bound to proteins in all undiluted samples. Total binding capacity was highest in rat and lowest in monkey. Human plasma showed a capacity of 1.5-2.1 microgram steroid/ml. In man, monkey and rabbit LN and G were specifically bound to the same degree as DHT, whereas NET binding was 50% lower. Specific binding of CPA to dog serum was 2-3 times higher than for other steroids. Two (high and low affinity) binding sites were found for LN, G and NET in man, monkey and rabbit and in dog for LN. Kd values for high affinity binding ranged from 3.5 (G in man) to 23 (NET in man) x 10(-9)M. Kd values of low affinity binding varied from 0.5 (CPA in dog) to 4 (NET in man) x 10(-6)M. E2 and DHT competition experiments confirmed the concept of SHBG as a carrier protein of 19-nor-progestins and DHT and its occurrence in man, monkey and rabbit. A sex hormone binding protein (SBP) in the dog seems to be responsible for the relatively high specific binding of CPA. SHBG is inducible by means of EE2 in man and monkey, but not in rabbit. EE2 may induce SBP in the dog. Comparison of in vitro Kds (high affinity binding) and in vivo metabolic clearance rates showed the same rankings for LN, G and NET in man, monkey and rabbit.     

Concentrations of copper, zinc, manganese, rubidium, and magnesium in thoracic empyemata and corresponding sera

In this study, a number of selected trace elements and clinically relevant parameters were compared between thoracic empyemata and the corresponding sera for a better understanding of the trace element distribution between these two compartments. Serum-empyema pairs were obtained from 13 patients and quantified for selected and essential trace elements, namely copper (Cu), zinc (Zn), manganese (Mn), rubidium (Rb), and magnesium (Mg), by inductively coupled plasma-mass spectrometry (ICP-MS). In addition, the concentrations of the following clinical laboratory parameters were analyzed by standard methods: total protein, leukocyte count, lactate dehydrogenase, glucose, pH, and the C-reactive protein. Individual concentrations of the elements determined in the empyemata were frequently higher than in pleural effusions of any other benign or malignant condition except for Cu. Serum Cu exceeded the normal range (600–1400 μg/kg) in 6 out of 13 patients (median 1410 μg/kg). In the empyemata, Zn concentrations (median 2000 μg/kg) were characteristically higher than in the sera (median 450 μg/kg) and exceeded the upper limit for serum (1200 μg/kg) in 8 of the 13 patients. Manganese concentrations in the empyemata (median 2.7 μg/kg) were also higher compared to corresponding sera, although they stayed within the limits considered normal for serum of healthy adults (upper limit 2.9 μg/kg). Rubidium was also moderately higher in most empyemata (median 290 μg/kg) and exceeded the upper limit for serum (560 μg/kg) in two patients. The median concentration of the essential element magnesium was higher in the empyemata (23 mg/kg) than in the sera (21 mg/kg). However, all serum Mg concentrations except three remained within the normal range (17–22 mg/kg). Removal of large amounts of empyematous fluid may deprive the body of trace elements and can cause suboptimal or deficient trace element status and homeostasis. Recuperation will be accelerated by compensatory supplementation of trace elements. Therefore, selective medication with adequate trace element compounds in patients with thoracic empyema can be generally recommended for zinc. The other elements need not necessarily be monitored or substituted, because of their stable concentrations in the serum. Rb may have a biological impact, but deficiency symptoms in man are not clearly defined. Deceased.     

Power output,mechanomyographic, and electromyographic responses to maximal,concentric, isokinetic muscle actions in men and women

The purpose of this study was to examine the responses of peak torque (PT), mean power output (MP), mechanomyographic (MMG) and electromyographic (EMG) amplitudes, and mean power frequencies (MPFs) of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) in men and women during dynamic muscle actions. Twelve women (mean +/- SD age = 22 +/- 3 years) and 11 men (22 +/- 3 years) performed maximal, concentric, isokinetic leg extensions at velocities of 60, 120, 180, 240, and 300 degrees x s(-1) on a Cybex 6000 dynamometer. Piezoelectric MMG-recording sensors and bipolar surface EMG electrodes were placed over the VL, RF, and VM muscles. No sex-related differences were found among the velocity-related patterns for PT, MP, MMG amplitude, MMG MPF, or EMG MPF. There were, however, sex-related differences in the patterns of EMG amplitude across velocity. The results indicated similar velocity-related patterns of increase of MP and MMG amplitude for all 3 muscles and of EMG amplitude for the VL and VM in the women. Velocity-related decreases (p 0.05) across velocity. MMG MPF increased (p < or = 0.05) only between 240 and 300 degrees x s(-1). Overall, these findings suggested that there were sex- and muscle-specific, velocity-related differences in the associations among motor unit activation strategies (EMG amplitude and MPF) and the mechanical aspects of muscular activity (MMG amplitude and MPF). With additional examination and validation, however, MMG may prove useful to practitioners for monitoring training-induced changes in muscle power output.     

Ethnic and sex differences in visceral,subcutaneous, and total body fat in children and adolescents

Objective: This study investigated ethnic and sex differences in the distribution of fat during childhood and adolescence. Design and Methods : A cross‐sectional sample (n = 382), aged 5–18 years, included African American males (n = 84), White males (n = 96), African American females (n = 118), and White females (n = 84). Measures for total body fat (TBF) mass and abdominal adipose tissue (total volume and L4‐L5 cross‐sectional area) for both subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) depots were assessed by dual‐energy X‐ray absorptiometry and magnetic resonance image, respectively. Analyses of covariance (ANCOVAs) were used to determine ethnic and sex differences in TBF (adjusted for age) and ethnic and sex differences in SAT and VAT (adjusted for both age and TBF). Results: Age‐adjusted TBF was greater in African Americans (P = 0.017) and females (P < 0.0001) compared with Whites and males, respectively. In age‐ and TBF‐adjusted ANCOVAs, no differences were found in the SAT. The VAT volume was, however, greater in Whites (P < 0.0001) and males (P < 0.0001) compared with African Americans and females, respectively. Similar patterns were observed in SAT and VAT area at L4‐L5. Conclusions: The demonstrated ethnic and sex differences are important confounders in the prevalence of obesity and in the assignment of disease risk in children and adolescents.     

Carboxyhemoglobinemia, polycythemia, cardiomegaly, and cardiovascular function in the anesthetized rat

The effects of carbon monoxide (CO), polycythemia (PC), and cardiomegaly (CM) on cardiovascular function were investigated in adult rats in which the latter two conditions were induced by 500 ppm CO inhalation for 5-6 weeks. Using an anesthetized open-chest preparation, these rats were compared with normal rats. With CO + PC + CM present, resting cardiac index, stroke index, stroke work, and minute work were elevated (heart rate also in the conscious state), while left ventricle end-diastolic pressure (LVDP) was normal. With PC + CM after CO washout, cardiac index and stroke index returned to normal at normal LVDP. Minute work, peripheral resistance, heart rate, and blood pressure, however, remained above normal. With CM alone, minute work, +dP/dtmax, +dF/dtmax, peripheral resistance, blood pressure, and LVDP declined from the condition with PC + CM. Although most cardiovascular parameters increased in the three conditions above with acutely increased LVDP, only with CM alone was performance augmentation normal. The results (i) reveal several characteristics of the hemodynamic response to chronic carboxyhemoglobinemia, (ii) suggest that the transient hypertension attending CO elimination in the presence of PC results from rapid reversal of peripheral vasodilatation, (iii) demonstrate decreased cardiac functional reserve with CO and (or) polycythemia upon preload challenge, and (iv) provide evidence for the benign nature of CO-induced cardiomegaly alone, on heart function.     

Bacteriochlorophyll c monomers,dimers, and higher aggregates in dichloromethane,chloroform, and carbon tetrachloride

Bacteriochlorophyll c in vivo is a mixture of at least 5 homologs, all of which form aggregates in CH₂Cl₂, CHCl₃ and CCl₄. Three homologs exist mainly in the 2-R-(1-hydroxyethyl) configuration, whereas the other two homologs, 4-isobutyl-5-ethyl and 4-isobutyl-5-methyl farnesyl bacteriochlorophyll c, exist mainly in the 2-S-(1-hydroxyethyl) configuration (Smith KM, Craig GW, Kehres LA and Pfennig N (1983) J. Chromatograph. 281: 209–223). In CCl₄ the S-homologs form an aggregate of 2–3 molecules whose absorption (747 nm maximum) and circular dichroism spectra resemble those of the chlorosome. In CH₂Cl₂, CHCl₃ and CCl₄ the 4-n-propyl homolog (R-configuration) forms dimers absorbing at ca. 680 nm and higher aggregates absorbing at 705–710 nm. In CCl₄ the dimerization constant is approx. 10 µM^–1 (1000 times that for chlorophyll a). The difference between the types of aggregates formed by the 4-n-propyl and 4-isobutyl homologs is attributed to the difference between the R- and S-configurations of the 2-(1-hydroxyethyl) groups in each chlorophyll.Abbreviations BChl bacteriochlorophyll - CD circular dichroism - Chl chlorophyll - DNS data not shown - EEF 4-ethyl-5-ethyl farnesyl - iBM/EF 4-isobutyl-5-methyl/ethyl farnesyl - MEF 4-methyl-5-ethyl farnesyl - PEP 4-n-propyl-5-ethyl farnesyl