The evolution of tail-length in widowbirds (Ploceidae): tests of alternatives to sexual selection

The long tails of male widowbirds (Euplectes , Ploceidae) have been used to test sexual selection theory, but alternatives to sexual selection have not been investigated. This study tests three alternative hypotheses for the evolution of tail-length in widowbirds: apose-matism, the unprofitable prey hypothesis and species recognition. Using museum specimens, geographic patterns of tail-length were examined for evidence of character convergence (as predicted by the aposematism and unprofitable prey hypotheses) or character divergence (as predicted by the species recognition hypothesis) in areas where two pairs of species were sympatric. There was no consistent trend: one species showed evidence of character convergence and the other some evidence of divergence. Experimental manipulation of tail-length in the Yellow-shouldered Widowbird Euplectes macrourus also failed to support the species recognition hypothesis: there was no preference for males with species-typical tail-lengths but only a slight and non-significant trend to favour short-tailed males. There was also no evidence that mistaken identity led to territory loss following these experimental manipulations. Tail-length of six Euplectes species did not correlate with unpalatability scores, as predicted by the aposematism hypothesis. These hypotheses do not appear to explain the evolution of long tails in widowbirds, suggesting that sexual selection is the sole factor favouring long tails. Interspecific variation in tail-length remains unexplained.     

Experimental evidence for female choice and energetic costs of male tail elongation in red-collared widowbirds

The black nuptial plumage of the highly polygynous male red‐collared widowbird (Euplectes ardens) comprises a red carotenoid‐based collar patch and a long graduated tail (c. 22 cm). Tail length was the strongest predictor of male mating success in a previous selection analysis, motivating this experimental test of the relative importance of tail plumes in male contest competition and female choice. Males were assigned to either a short (12.5 cm) or control (20 cm) tail manipulation prior to territory establishment. Male contest competition was unaffected by the tail treatments as the shortened‐ and control‐tailed males were equally successful in acquiring territories of similar size and quality. In contrast, however, although the longer‐tailed control males spent less time in flight and courtship displays, they attracted significantly more prospecting and nearly three times as many nesting females to their territories compared to the short‐tailed males. In further support of tail length as the primary mate choice cue, none of the other measured and potential female cues (e.g. body size, collar colorimetrics, territorial behaviours or territory quality) influenced male reproductive success. In addition to potentially increasing detectability (‘signal efficacy’), the long tail is also a likely indicator of male quality (‘signal content’). Despite the higher activities of short‐tailed males, control‐tailed males showed a steeper decline in condition (relative body mass) during the breeding season. Furthermore, both short‐ and control‐tailed residents lost more condition than did the short‐ and control‐treated floaters (males not establishing territories), suggesting an interaction between tail length and the costs of territory acquisition, defence and courtship displays. These results confirm the role of mate choice and honest quality advertising as the main selection pressures behind elongated tails in widowbirds. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86 , 35–43.     

Effects of an anabolic treatment before puberty with trenbolone acetate-oestradiol or oestradiol alone on growth rate, testicular development and luteinizing hormone and testosterone plasma concentrations

Scrotal circumference, growth and hormonal status after prepubertal anabolic treatments were studied in 18 conventional Belgian White Blue bulls from 3 to 13 mo of age. Young bulls were assigned into three groups: six untreated (control) bulls, six bulls implanted with 140 mg trenbolone acetate + 20 mg oestradiol (Revalor; TBA-E2) and six bulls treated with 45 mg oestradiol (Compudose; E2). Mean scrotal circumference was similar in the three groups at Day O (between 13.0 +/- 0.3 cm to 13.4 +/- 0.7 cm). From Days O to 230, scrotal circumference was strongly inhibited in implanted bulls, 23.2 +/- 1.4, 21.7 +/- 1.0 cm, respectively, for TBA-E2 and E2 at Day 210, as compared with 29.5 +/- 2.2 cm in control bulls (P < 0.001). Afterwards, differences lessened gradually and no significant divergence was observed between the three groups from Day 310. Average plasma luteinizing hormone (LH) concentrations were similar in the three groups throughout the assay. Mean testosterone levels remained extremely low upto Day 150 in TBA-E2 and E2 groups (0.6 +/- 0.6, 1.2 +/- 0.7 ng/ml, respectively) before they increased abruptly and reached values observed in control bulls at Day 180 (4.0 +/- 1.9 ng/ml). The pulsatil character of LH and testosterone profiles was abolished by the anabolic treatments. Luteinizing hormone-releasing hormone (LHRH) injection was followed by an immediate and sharp increase in plasma LH concentrations in all groups at Day 0. Anabolic treatments strongly reduced LH and testosterone responses to LHRH in treated groups.     

The effects of pheromonal stimuli on estrus and peripheral plasma estradiol in female gray short-tailed opossums (Monodelphis domestica)

Exposure to male pheromones is associated with the activation of vaginal estrus in gray short-tailed opossums. The effects of such exposure on peripheral plasma estradiol-17 beta (E) levels in this marsupial species were examined in this study. Mean E levels of 27.8 pg/ml +/- 4.4 in diestrous females living in a room containing only females were similar to those seen in other marsupials. Direct naso/oral exposure to pheromonal cues provided by males resulted in vaginal estrus in 75% of these females within 4 11 days. None of the females exposed to clean cages came into vaginal estrus. Animals that were in estrus at the time of blood sampling or came into estrus over the experimental period had significantly higher E levels (58.1 +/- 12.6 pg/ml) than females in the pheromone-exposed and control groups that did not come into estrus (23.3 +/- 8.2 pg/ml). These findings are discussed with respect to other marsupial and eutherian species.     

云南云县黑喉山鹪莺繁殖生态初报

2016年3~9月对云南云县中岭岗村(24°15′42″N,100°02′42″E,平均海拔1 650 m)的黑喉山鹪莺(Prinia atrogularis)繁殖生态进行了研究。研究期间共发现42巢,主要位于杂草丛中(n=37)和灌木丛(茶树)中(n=5),筑巢期一般5~6 d,巢材有蜘蛛丝、苔藓植物、茅草花、茅草叶、铁线莲花、竹根须、枯枝、棕丝、干枯草穗等。巢呈球状,中上部侧方开口,巢重为(8.3±1.7)g,巢长为(13.2±0.9)cm,宽为(8.2±0.5)cm,巢口长(4.9±0.7)cm,巢口宽为(4.0±0.5)cm(n=25)。窝卵数为(3.9±0.4)枚(n=21,3~4枚)。卵的底色为白色、淡绿或者淡粉,遍布褐红色斑点,有的在钝端呈环状。卵重为(1.38±0.09)g,卵长为(17.3±0.7)mm,宽为(12.6±0.3)mm,卵体积为(1.4±0.1)cm3(n=65)。孵卵期(13.9±0.9)d(n=5,13~15 d),育雏期为(13.5±1.3)d(n=4,12~15 d)。利用Logistic曲线拟合雏鸟体重及外部器官增长,雏鸟的体重和嘴峰在5日龄左右增长最快,体长、翼长、跗跖在7日龄增长最快。对繁殖时间和地点较近的28巢进行连续观察,其中有7巢成功、21巢失败。造成繁殖失败的主要原因分别是巢捕食(62%)、亲鸟弃巢(14%)、人为破坏(14%)。     

Characterization of male killer whale (Orcinus orca) sexual maturation and reproductive seasonality

Longitudinal serum testosterone concentrations (n=10 males) and semen production (n=2 males) in killer whales were evaluated to: (1) characterize fluctuations in serum testosterone concentrations with respect to reproductive maturity and season; (2) compare morphologic changes to estimated age of sexual maturity, based on changes in serum testosterone concentrations; and (3) evaluate seasonal changes in sperm production. Classification of reproductive status and age class was based on differences (P < 0.05) in serum testosterone concentrations according to age; juvenile males ranged from 1 to 7 years (mean+/-S.D. testosterone, 0.13+/-0.20 ng/mL), pubertal males from 8 to 12 years (2.88+/-3.20 ng/mL), and sexually mature animals were 13 years and older (5.57+/-2.90 ng/mL). For captive-born males, serum testosterone concentrations, total body length and height to width ratio of the dorsal fin were 0.7+/-0.7 ng/mL, 495.6+/-17.5 cm and 1.14+/-0.13c m, respectively, at puberty; at sexual maturity, these end points were 6.0+/-3.3 ng/mL, 548+/-20 cm and 1.36+/-0.1cm. Serum testosterone concentrations were higher (P<0.05) from March to June than from December to February in pubertal animals (4.2+/-3.4 ng/mL versus 1.4+/-2.6 ng/mL) and than from September to December in sexually mature animals (7.2+/-3.3 ng/mL versus 4.0+/-2.0 ng/mL). Ejaculates (n = 90) collected from two males had similar (P > 0.05) sperm concentrations across all months. These data represent the first comprehensive study on male testosterone concentrations during and after sexual maturation, and on reproductive seasonality in the killer whale.     

Final height in children with idiopathic growth hormone deficiency treated with recombinant human growth hormone: the Belgian experience

BACKGROUND: The growth response to recombinant hGH (rhGH) treatment and final height of 61 Belgian children (32 boys) with idiopathic growth hormone deficiency (GHD) were studied. PATIENTS/METHODS: Two patient groups were compared: Group 1 with spontaneous puberty (n = 49), Group 2 with induced puberty (n = 12). The patients were treated with daily subcutaneous injections of rhGH in a dose of 0.5-0.7 IU/kg/week (0.17-0.23 mg/kg/week) from the mean +/- SD age of 11.9 +/- 3.1 years during 5.1 +/- 2.1 years. RESULTS: rhGH treatment induced a doubling of the height velocity during the first year and resulted in a normalisation of height in 53 (87%) patients. Final height was -0.7 +/- 1.1 SDS, being 170.4 +/- 7.2 cm in boys and 158.0 +/- 6.4 cm in girls. Corrected for mid-parental height, final height was 0.0 +/- 1.1 SDS. Ninety-two percent of the patients attained an adult height within the genetically determined target height range. Although height gain during puberty was smaller in the patients with induced puberty (boys: 17.1 +/- 7.0 cm vs. 27.5 +/- 6.6 cm (p < 0.005); girls: 9.6 +/- 7.4 cm vs. 22.2 +/- 6.1 cm (p < 0.005)), no differences in final height after adjustment for mid-parental height were found between patients with spontaneous or induced puberty. CONCLUSIONS: We conclude that patients with idiopathic GHD treated with rhGH administered as daily subcutaneous injections in a dose of 0.5-0.7 IU/kg/week reach their genetic growth potential, resulting in a normalisation of height in the majority of them, irrespective of spontaneous or induced puberty.     

No difference in pubertal growth and final height between treated hypogonadal and non-hypogonadal thalassemic patients

BACKGROUND: Many factors can negatively affect growth in thalassemic patients, and hypogonadism has been considered as the main factor responsible for their pubertal growth failure. OBJECTIVE: To evaluate the influence of hypogonadism and its treatment on pubertal growth and final height in thalassemic patients. METHODS: We compared the growth of 28 hypogonadal thalassemic patients in whom puberty was induced to that of 25 patients in whom puberty occurred spontaneously. RESULTS: In both groups of patients we observed reduced peak height velocity (induced puberty: females 4.9 +/- 2.1, males 6.0 +/- 1.8 cm/year; spontaneous puberty: females 6.1 +/- 1.5, males 7.3 +/- 2.1 cm/year) and pubertal height gain (induced puberty: females 11.3 +/- 4.0, males 18.0 +/- 4.5 cm/year; spontaneous puberty: females 15.8 +/- 2.7, males 18.1 +/- 5.3 cm/year) and a short final height (induced puberty: females -1.8 +/- 0.7, males -2.1 +/- 1.0 SDS; spontaneous puberty: females -2.3 +/- 1.0, males -1.9 +/- 1.0 SDS). CONCLUSIONS: Poor pubertal growth is present in thalassemic patients regardless of hypogonadism. Other factors are responsible for the reduced growth spurt and the final short stature observed in these patients.     

Pharyngeal cross-sectional area in normal men and women

Pharyngeal size and the dynamic behavior of the upper airway may be important factors in modulating respiratory airflow. Patients with obstructive sleep apnea are known to have reduced pharyngeal cross-sectional area. However, no systematic measurements of pharyngeal area in healthy asymptomatic subjects are available, in part due to the lack of simple, rapid, and noninvasive measurement techniques. We utilized the acoustic reflection technique to measure pharyngeal cross-sectional area in 24 healthy volunteers (14 males, 10 females). Pharyngeal area was measured during a continuous slow expiration from total lung capacity (TLC) to residual volume (RV). We compared pharyngeal cross-sectional areas in males and females at three lung volumes: TLC, 50% of vital capacity (VC), and RV. In males, pharyngeal areas (means +/- SD) were 6.4 +/- 1.3 cm2 at TLC, 5.4 +/- 0.9 cm2 at 50% VC, and 4.1 +/- 0.8 cm2 at RV. In females, pharyngeal areas were 4.8 +/- 0.6 cm2 at TLC, 4.2 +/- 0.5 cm2 at 50% VC, and 3.7 +/- 0.6 cm2 at RV. The difference in area between males and females was statistically significant at TLC and 50% VC but not at RV. However, when the pharyngeal cross-sectional area was normalized for body surface area, this difference was not significant. In males there was a negative correlation of pharyngeal area with age. We conclude that sex differences in pharyngeal area are related to body size, pharyngeal area shows a similar variation with lung volumes in males and females, and in males pharyngeal area reduces with age.     

Collection of oocytes from cattle via follicular aspiration aided by ultrasound with or without gonadotropin pretreatment and in different reproductive stages

Ultrasound-guided follicular aspiration was performed on 29 Holstein-Friesian cows/heifers twice weekly at 3- to 4-d intervals over a period of 2 consecutive estrous cycles (total 42 d). For visualization of the ovaries and guidance of the aspiration needle, a 6.5 MHz fingertip probe on a 62 cm probe carrier was inserted into the vagina. The disposable aspiration needle was connected to a permanent rinse tubing system, thus ensuring minimum death of oocytes in the aspiration processs. After penetration of the vaginal wall, the needle was inserted into a follicle of the rectally fixed ovary. Cumulus oocyte complexes (COC) were aspirated at a pressure of 100 mm Hg. In the first experiment, the effect of an additional gonadotropin treatment 4 d prior to aspiration was investigated in 8 lactating cows. Following FSH-treatment, the number of aspirated follicles was higher (P < 0.05) than in the nontreated animals (10.6 +/- 0.7 vs 8.9 +/- 0.5). The number of recovered COC (7.0 +/- 0.6 vs 5.8 +/- 0.5), the recovery rate (COC per aspirated follicle) (66.6% vs 65.4%), the percentage of viable COC (56.8% vs 52.1%), the cleavage rate upon in vitro maturation and in vitro fertilization (56.7% vs 59.8%) as well as the rate of morula/blastocyst formation (3.8% vs 2.9%) were similar in both groups. In the second experiment, follicles were aspirated in 4 lactating cows, 6 dry cows, 4 pregnant cows (first 35 d of pregnancy), and 4 heifers. The average number of aspirated follicles and recovered COC was higher (P < 0.05) in the first 2 groups (10.6 +/- 0.6 and 9.3 +/- 0.7 follicles; 7.2 +/- 0.5 and 6.9 +/- 0.7 oocytes) than in trie 2 other treatment groups (7.3 +/- 0.5 and 8.1 +/- 0.5 follicles; 5.0 +/- 0.4 and 5.7 +/- 0.5 oocytes). The percentage of viable COC was higher (P < 0.05; 68.3%) in lactating animals than in all the other groups (49.7, 52.5 and 57.4%, respectively). Similarly, upon in vitro fertilization, cleavage rate was higher (P < 0.05; 63.4%) in lactating cows than in the other groups (43.7, 50.5, 55.1%, respectively). A total of 21.5, 22.7, 11.9 and 13.5%, respectively, in the 4 groups of the in vitro fertilized oocytes reached the morula and blastocyst stages. After transfer of a total of 48 embryos 22 pregnancies (45.8%) were established as detected on Day 65. We conclude that 1) repeated aspiration of viable COC at short intervals is possible, 2) additional FSH-treatment does not increase oocyte yields, and 3) viable blastocysts can be produced from cattle at various reproductive phases irrespective of the reproductive phase.     

Age-related changes in song repertoire size and song type sharing in the Whinchat Saxicola rubetra

In many oscine passerines males’ songs, the repertoire size increases with age. At the same time it often remains unknown when and where males learn new songs. To infer the Whinchat Saxicola rubetra song learning strategy, we described and catalogued song-type repertoire, revealed age differences and examined song sharing strategies among neighbouring and distant males. We recorded song vocalizations of 40 males in a limited (104 ha) study plot during four years. Whinchats produce short and discrete songs with clear intersong pauses. In total 45 song types were allocated, the individual repertoire size averaged 23.5 ± 7.6 song types (range 9–34 song types). The males’ age significantly influenced the song-type repertoire size. The second calendar year (first breeding) males had a lower repertoire size than the older males. The majority of song types were shared by less than half of males in our sample. The Jaccard similarity indexes varied from 0.5 to 0.7. We could not find a relationship between males’ song sharing and geographic distances between their nests. We assume that Whinchat males learned new songs in the local population before territory establishment.     

Urinary androgen concentrations and social status in two species of free ranging zebra (Equus burchelli and E. grevyi)

In both species of zebra, breeding males had higher urinary androgen concentrations (ng androgens/mg Cr) than did non-breeding bachelor males (30.0 +/- 5.0 (N = 9) versus 11.4 +/- 2.8, (N = 7) in the plains zebra; 19.0 +/- 2.2 (N = 17) versus 10.7 +/- 1.2 (N = 14) in the Grevy's zebra). In the more stable family structure of the plains zebra (single male non-territorial groups) variations in androgen concentrations could not be ascribed to any measured variable. In the Grevy's zebra, androgen values were significantly lower in samples taken from territorial (breeding) males which had temporarily abandoned their territories (N = 4) and the urinary androgen concentration for a male on his territory was negatively correlated with the time since females last visited the territory.     

Abolition of the seasonal release of luteinizing hormone and testosterone in Alpine male goats (Capra hircus) by short photoperiodic cycles.

This study was performed to determine whether rapid alternation between long and short days abolished seasonal variations in the activity of the hypothalamo-pituitary-testis axis observed normally in Alpine and Saanen male goats during the year. Three groups of 6 males were used: group 1 remained in open sheds under the natural annual change in daylength from 16 h of light (long day) to 8 h of light (short day). Group 2 was exposed to 1 month of long days alternated with 1 month of short days; and group 3 to 2 months of long days alternated with 2 months of short days. In group 1, blood samples were taken in December, February and June; in groups 2 and 3, samples were obtained once during short and long days for the melatonin assay. For luteinizing hormone and testosterone determinations monthly samples from group 1 were obtained from September to August while, in groups 2 and 3, blood samples were taken on 4 occasions during long and short days. Weekly blood samples were taken from all groups during the whole of the experiment to measure prolactin and testosterone concentrations. Melatonin profiles indicated that secretion by the pineal gland of male goats from the treated groups adapted to rapid changes in daylength: duration of nocturnal secretion was close to that of the dark period. Treated goats were also able to transduce this signal adequately and always responded to long days by increasing their prolactin concentration (mean +/- s.e.m.; group 2: 62.4 +/- 6.8 ng/ml; group 3: 102.3 +/- 15.7 ng/ml) and to short days with a decrease in prolactin concentrations (35.0 +/- 3.6 and 46.1 +/- 9.5 ng/ml, respectively). In the treated groups, luteinizing hormone pulse frequency varied with day length. In group 2, it was higher in long days (1.1 +/- 0.3 pulses in 8 hours) than in short days (0.7 +/- 0.3) while, in group 3, this frequency was higher in short days (1.9 +/- 0.3) than in long days (0.5 +/- 0.2). Testosterone secretion also varied with daylength; in group 2, the testosterone concentrations were maximum during long days (5.8 +/- 1.4 ng/ml) while in group 3 the maximum testosterone concentrations occurred during short days (6.4 +/- 1.2 ng/ml). These results lead to the conclusion that rapid alternation of long and short days either attenuated (group 3) or prevented (group 2) seasonal changes in the activity of the hypothalamo-pituitary axis.(ABSTRACT TRUNCATED AT 400 WORDS)     

Synchronisation of ovarian follicular waves in the dromedary camel (Camelus dromedarius)

This study was designed to compare the efficacy of various treatments intended to synchronise follicular wave cycles in dromedary camels by removing the existing follicle of unknown size and replacing it with a follicle capable of ovulating at a known time. Camels were randomly assigned to one of five groups and treated with either (1) 5mg oestradiol benzoate (i.m.) and 100mg progesterone (i.m.; E/P, n=15), (2) 20 icrog GnRH analogue, buserelin (i.m.; GnRH, n=15), (3) 20 microg buserelin (i.m.) on Day 0 (T=0) and 500 microg prostaglandin on Day T+7 (GnRH/PG n=15), (4) transvaginal ultrasound-guided follicle ablation of all follicles > or =0.5 cm (ABL, n=15) or (5) 5 ml saline (i.m; Controls n=15). All camels were subsequently injected with 20 microg buserelin 14 days after the first treatment was given. The ovarian response was monitored daily by transrectal ultrasonography and the intervals from treatment to follicular wave emergence and also the day on which the new dominant follicle reached 1.3 cm was recorded. Amongst the treatment groups the mean interval from treatment to new follicle wave emergence and treatment to time taken for the new dominant follicle to reach 1.3 cm in diameter was shortest in the ABL group (2.3+/-0.5 days and 8.8+/-1.1 days respectively, P=0.044) and longest in the E/P group (6.4+/-0.8 days and 12.2+/-1.0 days respectively, P<0.001) whereas the GnRH and GnRH/PG groups were intermediate (3.0+/-0.5 days and 11.1+/-0.8 days GnRH; and 4.5+/-0.5 days and 10.7+/-0.7 days GnRH/PG). A total of 11/15 camels in both the GnRH and GnRH/PG groups had dominant follicles between 1.3 and 1.9 cm 14 days post treatment, of which 21 of the 22 follicles ovulated after GnRH injection on T+14. The ABL, E/P and control groups however, showed greater variability in follicle size with less camels having dominant follicles between 1.3 and 1.9 cm than the GnRH and GnRH/PG groups and more in the > or =2.0 cm or follicle regressing groups, therefore fewer of these camels ovulated (ABL n=7; E/P n=9; Control n=6) after GnRH injection on Day T+14. In conclusion, two GnRH injections 14 days apart or two GnRH injections 14 days apart and PG on Day 7 after the first GnRH were the most effective methods to synchronise ovulation rate in dromedary camels at a fixed time interval of 14 days after treatment.     

印度地鼠的性成熟和窝仔数

为有效地进行有害脊椎动物的控制 ,研究了栖息于巴基斯坦Punjab中部的 348只印度地鼠的繁殖模式。在所捕捉到的 10 7雄鼠和 2 4 1只雌鼠中 ,分别有 75只和 179只是性成熟的个体。性比偏雌。使用被捕个体标本的体重和体长作为指标 ,发现最小的性成熟的雄性个体体重为 70 - 89g ,体长 13 1- 14 0cm ;一窝仔里面的平均胚胎数为 2 74± 0 15 (范围 ,1- 5 ) ,而平均胎斑数为 4 2 9± 0 19(1- 11) .体重似乎对窝仔数有显著影响 ,而体长和估计的年龄对窝仔数没影响。当老鼠繁殖不活跃和不繁殖时 ,控制害兽最有效     

Host sexual selection and cuckoo parasitism: an analysis of nest size in sympatric and allopatric magpie Pica pica populations parasitized by the great spotted cuckoo Clamator glandarius

Magpies (Pica pica) build large nests that are the target of sexual selection, since males of early breeding pairs provide many sticks for nests and females mated to such males enjoy a material fitness benefit in terms of better quality territory and parental care of superior quality. Great spotted cuckoos (Clamator glandarius) preferentially parasitize large magpie nests and sexual selection for large nests is thus opposed by natural selection due to brood parasitism. Consistent with the hypothesized opposing selection pressures, in a comparative analysis of 14 magpie populations in Europe we found that nest volume was consistently smaller in sympatry than in allopatry with the great spotted cuckoo, in particular in areas with a high parasitism rate and high rates of rejection of mimetic model cuckoo eggs. These observations are consistent with the suggestion that magpies have evolved a smaller nest size in areas where cuckoos have exerted strong selection pressures on them in the recent past.     

Effects of high altitude and water deprivation on arginine vasopressin release in men

High-altitude exposure changes the distribution of body water and electrolytes. Arginine vasopressin (AVP) may influence these alterations. The purpose of this study was to examine the effect of a 24-h water deprivation trial (WDT) on AVP release after differing altitude exposures. Seven healthy males (age 22 +/- 1 yr, height 176 +/- 2 cm, mass 75.3 +/- 1.8 kg) completed three WDTs: at sea level (SL), after acute altitude exposure (2 days) to 4,300 m (AA), and after prolonged altitude exposure (20 days) to 4,300 m (PA). Body mass, standing and supine blood pressures, plasma osmolality (Posm), and plasma AVP (PAVP) were measured at 0, 12, 16, and 24 h of each WDT. Urine volume was measured at each void throughout testing. Baseline Posm increased from SL to altitude (SL 291.7 +/- 0.8 mosmol/kgH2O, AA 299.6 +/- 2.2 mosmol/kgH2O, PA 302.3 +/- 1.5 mosmol/kgH2O, P < 0.05); however, baseline PAVP measurements were similar. Despite similar Posm values, the maximal PAVP response during the WDT (at 16 h) was greater at altitude than at SL (SL 1.7 +/- 0.5 pg/ml, AA 6.4 +/- 0.7 pg/ml, PA 8.7 +/- 0.9 pg/ml, P < 0.05). In conclusion, hypoxia appeared to alter AVP regulation by raising the osmotic threshold and increasing AVP responsiveness above that threshold.     

Nesting behavior of Podium denticulatum Smith (Hymenoptera: Sphecidae)

The nesting behavior of Podium denticulatum Smith was studied on the campus of Ribeir?o Preto of the Universidade de S?o Paulo, SP, Brazil, from September 2003 to August 2005. The wasps established their nests in bamboo canes ranging from 11.4 cm to 26.2 cm in length and from 0.7 cm to 1.8 cm in internal diameter. Podium denticulatum nested almost exclusively in the hot and wet season (September-April), producing at least five generations per year. The cell provisioning was made with adult and nymphal cockroaches (Blattellidae) which were arranged venter-up and with the head inward toward the inner end of the cell. The construction of a temporary closure occurred in cells that took more than one day to be provisioned. The cells provisioned with a greater number of prey were more likely to produce females than males. The nests included 1-6 brood cells separated by mud partitions and arranged in a linear series. The innermost cells of the nests produced females, and the outermost cells produced males. Nests were parasitized by Eulophidae (Melittobia sp.), Chrysididae and Tachinidae.     

Esophageal tone in patients with total aperistalsis: gastroesophageal reflux disease versus achalasia

We have evaluated esophageal tone in two different conditions that, in some cases, similarly impair phasic esophageal motility. Studies were performed in 14 healthy volunteers, 10 patients with total esophageal aperistalsis secondary to gastroesophageal reflux disease (GERD), and 25 untreated achalasia patients. We quantified esophageal compliance and relaxation induced by a nitric oxide donor using a barostat. Intraesophageal volume at a minimal distending pressure (2 mmHg) was not significantly different among all three groups (4.1 +/- 0.7, 3.8 +/- 0.7, and 4.2 +/- 1.2 ml for healthy, GERD, and achalasia groups, respectively). Esophageal compliance was significantly increased (P < 0.05 vs. healthy group) in the two groups of patients with aperistalsis (1.9 +/- 0.2, 3.0 +/- 0.2, and 3.1 +/- 0.3 ml/mmHg for healthy, GERD, and achalasia groups, respectively). Esophageal relaxation was decreased in GERD patients (Delta diameter: 0.4 +/- 0.1 cm) and increased in achalasia patients (Delta diameter: 1.3 +/- 0.4 cm) relative to healthy subjects (Delta diameter: 0.9 +/- 0.2 cm) (P < 0.05 for GERD vs. achalasia and healthy groups). Our results indicate that diseases that similarly impair phasic esophageal motility may affect esophageal tone differently.     

Insulin-like growth factor I (IGF-I) and insulin binding to erythrocytes of normal prepubertal children and adults.

Erythrocyte insulin-like growth factor I (IGF-I) and insulin receptors were characterized in 10 normal prepubertal children (5 girls and 5 boys) aged 4-11 yrs and 10 normal adults (4 women and 6 men) aged 32-47 yrs. erythrocytes were purified from 5 ml of blood by Ficoll-Paque gradient centrifugation. Reticulocytes count in the erythrocyte suspensions were lower than 1%. Insulin and IGF-I binding assays were performed simultaneously. Maximal percent binding of [125I] labelled IGF-I was significantly higher in prepubertal children than in adults (8.7 +/- 0.7% versus 6.2 +/- 0.5% at a concentration of 5 x 10(9) erythrocytes/ml). Scatchard analysis revealed the high affinity constant was better in prepubertal children (Ka = 4.6 +/- 1.3 nM-1 versus 1.8 +/- 0.2 nM-1), whereas the binding capacity was similar (5.8 +/- 1.1 versus 7.7 +/- 0.8 high affinity binding sites/cell). In both groups, unlabelled IGF-I inhibited tracer-binding half maximally at about 1 nM. Insulin was 100-fold less potent. In adults, specific binding of [125I] labelled IGF-I was higher in women (7.6 +/- 0.7%) than in men (5.3 +/- 0.4%). No significant difference was observed in maximal specific binding of [125I] labelled insulin between prepubertal children (8.2 +/- 0.5%) and adults (7.2 +/- 0.7%). In both groups, competition by unlabelled insulin for [125I] labelled insulin binding gave 50% displacement for approximately 0.25 nM and IGF-I was about 80-fold less potent. Both IGF-I and insulin binding parameters were not significantly correlated with plasma hormone levels. In prepubertal children, the high-affinity IGF-I receptors number decreased with increasing high-affinity insulin receptors number.(ABSTRACT TRUNCATED AT 250 WORDS)