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- Elmendorf, Sarah C., et al.
(author)
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Global assessment of experimental climate warming on tundra vegetation : heterogeneity over space and time
- 2012
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In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 15:2, s. 164-175
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Research review (peer-reviewed)abstract
- Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation and associated ecosystem consequences have the potential to be much greater than we have observed to date.
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| 2. |
- Samuk, Inbal, et al.
(author)
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Anorectal malformations and perineal hemangiomas : The Arm-Net Consortium experience
- 2019
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In: Journal of Pediatric Surgery. - : Elsevier BV. - 0022-3468. ; 54:10, s. 1993-1997
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Journal article (peer-reviewed)abstract
- Aim: Perineal hemangiomas rarely occur in patients with anorectal malformations (ARMs), but they can pose a significant challenge and warrant special attention. Surgical incision of posterior sagittal anorectoplasty (PSARP) may involve the hemangioma site resulting in hemorrhage, damage to blood supply, leading to complications and adversely affecting outcome. The aim of this study was to review the experience of the ARM-Net Consortium in the management of perineal hemangioma associated with ARM and evaluate treatment strategies. Materials and methods: Data on all patients with ARM and a perineal hemangioma located in the planes of the PSARP dissection who were managed at participating ARM-Net centers were collected retrospectively by questionnaire, as follows: ARM type, hemangioma distribution and penetration, imaging findings, medical/surgical management, timing of definitive repair, complications and outcome. Results: Ten patients from eight centers were included. Three patients each had a rectobulbar or rectovestibular fistula, 2 had a rectoperineal fistula, and one had a rectoprostatic fistula; in one patient, the hemangioma was too disfiguring to determine malformation type. Mean follow-up time was 36.6 months (median 29 months). Colostomies were performed before definitive repair in 8 patients. Five patients received systemic beta-blockers before PSARP: 3 were operated uneventfully following partial/complete involution of the hemangioma, and 2 are awaiting surgery. The two patients with rectoperineal fistula were managed expectantly. The remaining 3 patients underwent surgery with no preoperative medical treatment, and all had complications: mislocated neoanus in three and complete perineal dehiscence in one. Conclusion: Attempting PSARP in the presence of a perineal hemangioma may lead to complications and adversely affect outcome. This study confirms the benefits of beta blocker treatment before surgical reconstruction. Level of evidence: Treatment study, level III.
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| 3. |
- Samuk, Inbal, et al.
(author)
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Perineal Groove : An Anorectal Malformation Network, Consortium Study
- 2020
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In: Journal of Pediatrics. - : Elsevier BV. - 0022-3476. ; 222, s. 207-212
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Journal article (peer-reviewed)abstract
- Objective: To review the Anorectal Malformation Network experience with perineal groove (PG) focusing on its clinical characteristics and management. Study design: Data on patients with PG managed at 10 participating Anorectal Malformation Network centers in 1999-2019 were collected retrospectively by questionnaire. Results: The cohort included 66 patients (65 females) of median age 1.4 months at diagnosis. The leading referral diagnosis was anal fissure (n = 20 [30.3%]): 23 patients (34.8%) had anorectal malformations. Expectant management was practiced in 47 patients (71.2%). Eight (17%) were eventually operated for local complications. The median time to surgery was 14 months (range, 3.0-48.6 months), and the median age at surgery was 18.3 months (range, 4.8-58.0 months). In the 35 patients available for follow-up of the remaining 39 managed expectantly, 23 (65.7%) showed complete or near-complete self-epithelization by a mean age 15.3 months (range, 1-72 months) and 4 (11.4%) showed partial self-epithelization by a mean age 21 months (range, 3-48 months). Eight patients showed no resolution (5 were followed for ≤3 months). Nineteen patients (28.7%) were primarily treated with surgery. In total, 27 patients were operated. Dehiscence occurred in 3 of 27 operated patients (11.1%). Conclusions: PG seems to be an underestimated anomaly, frequently associated with anorectal malformations. Most cases heal spontaneously; therefore, expectant management is recommended. When associated with anorectal malformations requiring reconstruction, PG should be excised in conjunction with the anorectoplasty.
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