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Tropical Malaysians and temperate Koreans exhibit significant differences in sweating sensitivity in response to iontophoretically administered acetylcholine

Lee JB, Bae JS, Matsumoto T, Yang HM, Min YK

Int J Biometeorol, 2009 Mar;53(2):149-57.
PMID: 19048305 DOI: 10.1007/s00484-008-0197-9

Natives of the tropics are able to tolerate high ambient temperatures. This results from their long-term residence in hot and often humid tropical climates. This study was designed to compare the peripheral mechanisms of thermal sweating in tropical natives with that of their temperate counterparts. Fifty-five healthy male subjects including 20 native Koreans who live in the temperate Korean climate (Temperate-N) and 35 native tropical Malaysian men that have lived all of their lives in Malaysia (Tropical-N) were enrolled in this study after providing written informed consent to participate. Quantitative sudomotor axon reflex testing after iontophoresis (2 mA for 5 min) with 10% acetylcholine (ACh) was used to determine directly activated (DIR) and axon reflex-mediated (AXR) sweating during ACh iontophoresis. The sweat rate, activated sweat gland density, sweat gland output per single gland activated, and oral and skin temperature changes were measured. The sweat onset time of AXR (nicotinic-receptor-mediated) was 56 s shorter in the Temperate-N than in the Tropical-N subjects (P < 0.0001). The nicotinic-receptor-mediated sweating activity AXR (1), and the muscarinic-receptor-mediated sweating activity DIR, in terms of sweat volume, were 103% and 59% higher in the Temperate-N compared to the Tropical-N subjects (P < 0.0001). The Temperate-N group also had a 17.8% (P < 0.0001) higher active sweat gland density, 35.4% higher sweat output per gland, 0.24 degrees C higher resting oral temperature, and 0.62 degrees C higher resting forearm skin temperature compared to the Tropical-N subjects (P < 0.01). ACh iontophoresis did not influence oral temperature, but increased skin temperature near where the ACh was administered, in both groups. These results suggest that suppressed thermal sweating in the Tropical-N subjects was, at least in part, due to suppressed sweat gland sensitivity to ACh through both recruitment of active sweat glands and the sweat gland output per each gland. This physiological trait guarantees a more economical use of body fluids, thus ensuring more efficient protection against heat stress.
Shifts in mosquito diversity and abundance along a gradient from oil palm plantations to conterminous forests in Borneo

Young KI, Buenemann M, Vasilakis N, Perera D, Hanley KA

Ecosphere, 2021 Apr;12(4).
PMID: 33996190 DOI: 10.1002/ecs2.3463

Deforestation precipitates spillover of enzootic, vector-borne viruses into humans, but specific mechanisms for this effect have rarely been investigated. Expansion of oil palm cultivation is a major driver of deforestation. Here, we demonstrate that mosquito abundance decreased over ten stepwise distances from interior forest into conterminous palm plantations in Borneo. Diversity in interior plantation narrowed to one species, Aedes albopictus, a potential bridge vector for spillover of multiple viruses. A. albopictus was equally abundant across all distances in forests, forest-plantation edge, and plantations, while A. niveus, a known vector of sylvatic dengue virus, was found only in forests. A. albopictus collections were significantly female-biased in plantation but not in edge or forest. Our data reveal that the likelihood of encountering any mosquito is greater in interior forest and edge than plantation, while the likelihood of encountering A. albopictus is equivalent across the gradient sampled from interior plantation to interior forest.
Multivariate Prediction of Intraoperative Abandonment of Ileal Pouch Anal Anastomosis

Poh KS, Qureshi S, Hong YK, Moreno T, Stocchi L, Hull T, et al.

Dis Colon Rectum, 2020 05;63(5):639-645.
PMID: 32032200 DOI: 10.1097/DCR.0000000000001617

BACKGROUND: Restorative total proctocolectomy with IPAA may not be feasible in some patients because of technical intraoperative limitations.
OBJECTIVE: This study aimed to assess preoperative predictors for intraoperative IPAA and review management.
DESIGN: This is a retrospective review.
SETTING: This study was conducted at Cleveland Clinic between January 2010 and May 2018.
PATIENTS: Patients ≥18 years of age who underwent ileoanal pouch surgery were included. Patients with successful pouch creation as planned were grouped as "successful IPAA creation." Operative reports of patients who underwent alternative procedures were reviewed to identify cases when the pouch was preoperatively planned but intraoperatively abandoned (IPAA-abandoned group). Multivariate logistic regression models were developed to determine predictors of intraoperative pouch abandonment. We also reviewed the management of patients in whom the initial pouch creation failed.
MAIN OUTCOME MEASURES: The primary outcomes measured were preoperative predictors for intraoperative ileoanal pouch abandonment.
RESULTS: A total of 1438 patients were offered an ileoanal pouch; 21 (1.5%) experienced pouch abandonment due to inadequate reach (n = 17) and other technical reasons (n = 4). These patients underwent alternative procedures such as end or loop ileostomy with/without proctectomy. Multivariate logistic regression analysis indicated male sex (OR, 6.021; 95% CI, 1.540-23.534), BMI (OR, 1.217; 95% CI, 1.114-1.329), and a 2-stage procedure (OR, 14.510; 95% CI, 4.123-51.064) as independent factors associated with intraoperative abandonment of pouch creation. Alternative procedures were total proctocolectomy with end ileostomy (n = 14) and total abdominal colectomy with end ileostomy without proctectomy (n = 7). Ultimately, pouch creation was achieved in 6 of 21 patients after a median interval of 8.8 (range, 4.1-34.8) months. All patients had intentional weight loss before a reattempt and total abdominal colectomy with end ileostomy without proctectomy as their initial procedure.
LIMITATIONS: This study was limited by its retrospective nature.
CONCLUSIONS: Ileoanal pouch abandonment is rare and can be mitigated by initial total abdominal colectomy and weight loss. Male, obese patients are at a higher risk of failure. Intraoperative assessment of ileoanal pouch feasibility should occur before rectal dissection. See Video Abstract at http://links.lww.com/DCR/B156. PREDICCIÓN MULTIVARIANTE DEL ABANDONO INTRAOPERATORIO DE LA ANASTOMOSIS ANAL CON BOLSA ILEAL: La proctocolectomía total restaurativa con anastomosis de bolsa ileoanal puede no ser posible en algunos pacientes debido a limitaciones técnicas intraoperatorias.Evaluar los predictores preoperatorios para el abandono intraoperatorio de la bolsa ileoanal y revisar el manejo.Revisión retrospectiva.Cleveland Clinic entre Enero de 2010 y mayo de 2018.Pacientes > 18 años que se sometieron a cirugía de bolsa ileoanal. Los pacientes con una creación exitosa de la bolsa según lo planeado se agruparon como "creación exitosa de anastomosis de bolsa ileoanal". Se revisaron los informes operativos de los pacientes que se sometieron a procedimientos alternativos para identificar los casos en que la bolsa se planificó preoperatoriamente pero se abandonó intraoperatoriamente (grupo de "anastomosis anal de bolsa ileoanal abandonada"). Se desarrollaron modelos de regresión logística multivariante para determinar los predictores del abandono intraoperatorio de la bolsa. También revisamos el manejo de pacientes que fallaron en la creación inicial de la bolsa.Predictores preoperatorios para el abandono intraoperatorio de la bolsa ileoanal.A un total de 1438 pacientes se les ofreció una bolsa ileoanal; 21 (1.5%) experimentaron abandono de la bolsa debido a un alcance inadecuado (n = 17) y otras razones técnicas (n = 4). Estos pacientes se sometieron a procedimientos alternativos como ileostomía final o de asa con / sin proctectomía. El análisis de regresión logística multivariante indicó género masculino (OR, 6.021; IC 95%, 1.540-23.534), índice de masa corporal (OR, 1.217; IC 95%, 1.114-1.329) y procedimiento en 2 etapas (OR, 14.510; IC 95%, 4.123-51.064) como factores independientes asociados con el abandono intraoperatorio de la creación de la bolsa. Los procedimientos alternativos fueron la proctocolectomía total con ileostomía final (n = 14) y la colectomía abdominal total con ileostomía final sin proctectomía (n = 7). Finalmente, la creación de la bolsa se logró en 6/21 pacientes después de un intervalo medio de 8.8 (rango, 4.1-34.8) meses. Todos los pacientes tuvieron pérdida de peso intencional antes de la reintenta y colectomía abdominal total con ileostomía final sin proctectomía como procedimiento inicial.Naturaleza retrospectiva.El abandono de la bolsa ileoanal es raro y puede mitigarse mediante la colectomía abdominal total inicial y la pérdida de peso. Los pacientes masculinos y obesos tienen un mayor riesgo de fracaso. La evaluación intraoperatoria de la viabilidad de la bolsa ileoanal debe ocurrir antes de la disección rectal. Consulte Video Resumen en http://links.lww.com/DCR/B156. (Traducción-Dr. Yesenia Rojas-Kahlil).
Fulltext Abundance and distribution of sylvatic dengue virus vectors in three different land cover types in Sarawak, Malaysian Borneo

Young KI, Mundis S, Widen SG, Wood TG, Tesh RB, Cardosa J, et al.

Parasit Vectors, 2017 Aug 31;10(1):406.
PMID: 28859676 DOI: 10.1186/s13071-017-2341-z

BACKGROUND: Mosquito-borne dengue virus (DENV) is maintained in a sylvatic, enzootic cycle of transmission between canopy-dwelling non-human primates and Aedes mosquitoes in Borneo. Sylvatic DENV can spill over into humans living in proximity to forest foci of transmission, in some cases resulting in severe dengue disease. The most likely vectors of such spillover (bridge vectors) in Borneo are Ae. albopictus and Ae. niveus. Borneo is currently experiencing extensive forest clearance. To gauge the effect of this change in forest cover on the likelihood of sylvatic DENV spillover, it is first necessary to characterize the distribution of bridge vectors in different land cover types. In the current study, we hypothesized that Ae. niveus and Ae. albopictus would show significantly different distributions in different land cover types; specifically, we predicted that Ae. niveus would be most abundant in forests whereas Ae. albopictus would have a more even distribution in the landscape.
RESULTS: Mosquitoes were collected from a total of 15 sites using gravid traps and a backpack aspirator around Kampong Puruh Karu, Sarawak, Malaysian Borneo, where sylvatic DENV spillover has been documented. A total of 2447 mosquitoes comprising 10 genera and 4 species of Aedes, were collected over the three years, 2013, 2014 and 2016, in the three major land cover types in the area, homestead, agriculture and forest. Mosquitoes were identified morphologically, pooled by species and gender, homogenized, and subject to DNA barcoding of each Aedes species and to arbovirus screening. As predicted, Ae. niveus was found almost exclusively in forests whereas Ae. albopictus was collected in all land cover types. Aedes albopictus was significantly (P = 0.04) more abundant in agricultural fields than forests. Sylvatic DENV was not detected in any Aedes mosquito pools, however genomes of 14 viruses were detected using next generation sequencing.
CONCLUSIONS: Land cover type affects the abundance and distribution of the most likely bridge vectors of sylvatic DENV in Malaysia Borneo. Conversion of forests to agriculture will likely decrease the range and abundance of Ae. niveus but enhance the abundance of Ae. albopictus.
Fulltext Characterization of Three New Insect-Specific Flaviviruses: Their Relationship to the Mosquito-Borne Flavivirus Pathogens

Guzman H, Contreras-Gutierrez MA, Travassos da Rosa APA, Nunes MRT, Cardoso JF, Popov VL, et al.

Am J Trop Med Hyg, 2018 02;98(2):410-419.
PMID: 29016330 DOI: 10.4269/ajtmh.17-0350

Three novel insect-specific flaviviruses, isolated from mosquitoes collected in Peru, Malaysia (Sarawak), and the United States, are characterized. The new viruses, designated La Tina, Kampung Karu, and Long Pine Key, respectively, are antigenically and phylogenetically more similar to the mosquito-borne flavivirus pathogens, than to the classical insect-specific viruses like cell fusing agent and Culex flavivirus. The potential implications of this relationship and the possible uses of these and other arbovirus-related insect-specific flaviviruses are reviewed.