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  • Hymenoptera  (2)
  • Osteoporosis  (2)
  • Springer  (4)
  • Public Library of Science (PLoS)
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  • Springer  (4)
  • Public Library of Science (PLoS)
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  • 1
    Electronic Resource
    Electronic Resource
    Amylin increases bone volume but cannot ameliorate diabetic osteopenia (1995)
    Springer
    Calcified tissue international 56 (1995), S. 54-61 
    Details
    ISSN: 1432-0827
    Keywords: Diabetes mellitus ; Amylin ; Osteoporosis ; Bone mineral metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Amylin is normally secreted in a regulated fashion by the pancreatic β-cells in parallel with insulin and has been reported to have bone-conserving properties. Type I diabetes mellitus results in a low-turnover osteopenia in the presence of decreased amylin, which is in contrast to type II diabetes where less bone loss, in the presence of high amylin levels, occurs. We investigated the effects of amylin on bone mineral metabolism in normal and dibetic (streptozotocin-induced) rats, in order to ascertain whether amylin would modify the streptozotocin-induced diabetic osteopenia. Tenweek-old male Sprague-Dawley rats were randomized as follows: group A (n=18) received normal saline; group B (n=18) received amylin; group C, diabetic rats (n=23), received normal saline; and group D, diabetic rats (n=23), received amylin. Amylin (100 pmol/100 g b. w.) was administered by a daily subcutaneus injection. Double calceinlabeled tibiae were removed for histomorphometric analysis followed sacrifice on day 19. Results showed no difference in blood ionized calcium between groups. Blood glucose remained above 600 mg/dl in the diabetic animals and was not affected by the administration of amylin. Serum osteocalcin, insulin-like growth factor-1 (IGF-1), parathyroid hormone (PTH), and 1,25 dihydroxyvitamin D [1,25(OH)2D] were significantly lower in the diabetic rats compared with control group A by day 19. Amylin produced higher levels of serum osteocalcin in group B on day 9 (P〈0.05) compared with controls but returned to control values (group A) by day 19; no such change occurred in the diabetic group. Amylin administration did not influence IGF-1, 1,25(OH)2D or PTH levels compared with the untreated animals. Analysis of the bone histomorphometry showed a low-turnover osteopenia in the diabetic animals. Amylin administration resulted in a significant increase in bone volume in the normal rats, group B (P〈0.05), but was unable to significantly alter this parameter in the diabetic animals. In conclusion, amylin has a beneficial effect on the bone metabolism of the rat in vivo by increasing bone volume. It is, however, unable to overcome the osteopenia caused by streptozotocin-induced diabetes mellitus at the doses used in this study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298745
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  • 2
    Electronic Resource
    Electronic Resource
    When should bone density measurements be repeated? (1994)
    Springer
    Calcified tissue international 55 (1994), S. 243-248 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Bone density ; Longitudinal studies ; Statistical models ; Decision models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We calculated how long to wait before repeating bone mineral density (BMD) measurements to reassess fracture risk. Correlation results from serial measurements of 495 postmenopausal Japanese-American women were used to estimate 95% confidence intervals (CI) for future BMD. After 7 years of follow-up, BMD correlations with the initial measurement ranged between 0.81 and 0.94, depending on age group and measurement site. In this analysis, the period between measurements was defined as the time required for the lower 95% CI to fall below the BMD value corresponding to doubling of fracture risk. Progressive bone loss causes fracture risk to double after 10 years, on average. However, the 95% CIs indicate that a second BMD measurement will detect risk doubling after only 2 or 3 years for some women. For untreated, early postmenopausal women, the period between measurements was approximately 2–5 years for the radius and 4–6 years for the calcaneus, depending on the initial BMD level. The period was approximately 1 year longer for women age 60 and older. Treatments that halve the bone loss rate would increase the period by 1–3 years. In the absence of a second measurement of BMD, the CI will continue to expand with time, corresponding to a wider range in risk between individuals, and a greater proportion of women will be at increased fracture risk. Obtaining a second BMD measurement pinpoints the patient's status within the precision of the measurement. We conclude that repeated BMD measurements will provide a more accurate estimate of fracture risk than a single, baseline measurement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310399
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  • 3
    Electronic Resource
    Electronic Resource
    Neotropical ant gardens (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 1791-1816 
    Details
    ISSN: 1573-1561
    Keywords: Ant ; ant garden ; Hymenoptera ; Formicidae ; Camponotus ; chemical mimicry ; citronellol ; convergent evolution ; epiphyte ; mellein ; methyl 6-methylsalicylate ; Perú ; seed dispersal ; symbiosis ; tropical forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In ant gardens of lowland Amazonia, parabiotic ant speciesCamponotus femoratus andCrematogaster cf.limata parabiotica cultivate a taxonomically diverse group of epiphytic plants, whose establishment is restricted to arboreal carton ant nests. Epiphyte seeds are collected by workers ofCa. femoratus, the larger of the two ants, and stored unharmed in brood chambers where they subsequently germinate. Although seeds of some ant-garden epiphytes bear nutritional rewards, previous studies have shown that these rewards are not sufficient to explain the pattern of ant attraction to seeds. Five aromatic compounds occur frequently in and on the seeds of most ant-garden epiphytes and may be chemical cues by which ants recognize propagules of their symbiotic plants. The most widely distributed of these is methyl 6-methylsalicylate [6-MMS]1, previously reported as a major mandibular gland product in relatedCamponotus species and present in trace quantities inCa. femoratus males. (−)-Citronellol6 (previously unreported inCamponotus) was the principal volatile constituent in extracts of male heads, and (−)-mellein7 was present in small quantities. Discovery of 6-MMS inside the mandibular glands of maleCa. femoratus (and its presence in analogous glands of related ants) offers preliminary support for Ule's (1906) hypothesis that seeds attract ants by mimicking ant brood. In addition, the likely fungistatic activity of seed compounds suggests that they could retard microbial pathogens of ants and plants in the organic detritus of nest gardens. While the presence of identical seed compounds in so many unrelated plant lineages might represent a remarkable case of convergent evolution, other interpretations are possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01020495
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  • 4
    Electronic Resource
    Electronic Resource
    Neotropical ant gardens II. Bioassays of seed compounds (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 2993-3013 
    Details
    ISSN: 1573-1561
    Keywords: Ant ; ant-garden ; benzothiazole ; Camponotus ; Hymenoptera ; Formicidae ; chemical mimicry ; epiphyte ; 2-hydroxy-3-methoxybenzene-methanol ; 1-(2-hydroxy-4-methoxyphenyl)ethanone ; 2-hydroxy-6-methyl-benzoic acid ; methyl ester ; 1-(2-hydroxy-6-methylphenyl)ethanone ; 1-(2,4-dihydroxyphenyl)ethanone ; limonene ; 6-methyl-methylsalicylate ; 6-MMS ; seed dispersal ; symbiosis ; tropical forests ; vanillin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A number of volatile compounds occur on the seeds of taxonomically unrelated ant-garden epiphytes in western Amazonia. In field trials in southeastern Peru, we assayed the responses of ant-garden ants (Camponotus femoratus) to these and structurally similar compounds applied to artificial “seeds” made from zeolite molecular sieves. Benzothiazole,2, present on seeds of eight ant-garden epiphytes, repelled ants over the range of concentrations tested, as did 1-(2-hydroxy-6-methylphenyl)ethanone,3, occurring on seeds of six ant-garden epiphytes. 2-Hydroxy-6-methylbenzoic acid, methyl ester (methyl-6-methylsalicylate, 6-MMS),1, found on seeds of at least nine ant-garden epiphytes, was mildly repellent at high concentration, but stimulated excitement, seed handling, and (rarely) seed carrying at lower concentrations. Vanillin,5, a seed compound of four ant-garden epiphytes, and limonene,6, a monoterpene from seeds of three ant-garden epiphytes, both stimulated excitement, alarm, seed handling, and (rarely) seed carrying. Identified from seeds of seven ant-garden epiphytes, 1-(2,4-dihydroxyphenyl)ethanone,4, elicited little or no response. Among 70 compounds tested (mainly aromatic compounds), those found on seeds of ant-garden epiphytes or having structural features in common with such compounds were the most attractive to the ants. Although not present on epiphyte seeds, 2-hydroxy-3-methoxybenzenemethanol,10, consistently stimulated seed transport to the nest in one year, but did so only rarely in subsequent years. Some of the volatile compounds on seeds of ant-garden epiphytes probably play a role in ant attraction to epiphyte seeds, but evidence remains ambiguous. Finally,Ca. femoratus responded to one test compound [1-(2-hydroxy-4-methoxyphenyl)ethanone,60] (absent from epiphyte seeds) by descending from the vegetation to the ground.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00979490
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