Disentangling the roles of chance, abiotic factors and biotic interactions among epiphytic bryophyte communities in a tropical rainforest (Yunnan, China).

Epiphytes offer an appealing framework to disentangle the contributions of chance, biotic and abiotic drivers of species distributions. In the context of the stress-gradient theory, we test the hypotheses that (i) deterministic (i.e., non-random) factors play an increasing role in communities from young to old trees, (ii) negative biotic interactions increase on older trees and towards the tree base, and (iii) positive interactions show the reverse pattern. Bryophyte species distributions and abiotic conditions were recorded on a 1.1 ha tropical rainforest canopy crane site. We analysed co-occurrence patterns in a niche modelling framework to disentangle the roles of chance, abiotic factors and putative biotic interactions among species pairs. 76% of species pairs resulted from chance. Abiotic factors explained 78% of non-randomly associated species pairs, and co-occurrences prevailed over non-coincidences in the remaining species pairs. Positive and negative interactions mostly involved species pairs from the same versus different communities (mosses versus liverworts) and life forms, respectively. There was an increase in randomly associated pairs from large to small trees. No increase in negative interactions from young to old trees or from the canopy to the base was observed. Our results suggest that epiphytic bryophyte community composition is primarily driven by environmental filtering, whose importance increases with niche complexity and diversity. Biotic interactions play a secondary role, with a very marginal contribution of competitive exclusion. Biotic interactions vary among communities (mosses versus liverworts) and life forms, facilitation prevailing among species from the same community and life form, and competition among species from different communities and life forms.

A Regional Decision Support Scheme for Pest Risk Analysis in Southeast Asia.

A key justification to support plant health regulations is the ability of quarantine services to conduct pest risk analyses (PRA). Despite the supranational nature of biological invasions and the close proximity and connectivity of Southeast Asian countries, PRAs are conducted at the national level. Furthermore, some countries have limited experience in the development of PRAs, which may result in inadequate phytosanitary responses that put their plant resources at risk to pests vectored via international trade. We review existing decision support schemes for PRAs and, following international standards for phytosanitary measures, propose new methods that adapt existing practices to suit the unique characteristics of Southeast Asia. Using a formal written expert elicitation survey, a panel of regional scientific experts was asked to identify and rate unique traits of Southeast Asia with respect to PRA. Subsequently, an expert elicitation workshop with plant protection officials was conducted to verify the potential applicability of the developed methods. Rich biodiversity, shortage of trained personnel, social vulnerability, tropical climate, agriculture-dependent economies, high rates of land-use change, and difficulties in implementing risk management options were identified as challenging Southeast Asian traits. The developed methods emphasize local Southeast Asian conditions and could help support authorities responsible for carrying out PRAs within the region. These methods could also facilitate the creation of other PRA schemes in low- and middle-income tropical countries.

Microsurgical free flaps at Kathmandu Model Hospital.

BACKGROUND: Microsurgery is an emerging subspecialty in Nepal. Microsurgery was started at Kathmandu Model Hospital in 2007 with the support from Interplast Australia and New Zealand. This study will be useful for establishing a baseline for future comparisons of outcome variables and for defining the challenges of performing microsurgical free flaps in Nepal. METHODS: A retrospective cross sectional study was conducted using the clinical records of all the microsurgical free flaps performed at Kathmandu Model Hospital from April 2007 to April 2014. RESULTS: Fifty-six free flaps were performed. The commonest indication was neoplasm followed by post-burn contracture, infection and trauma. Radial artery forearm flap was the commonest flap followed by fibula, antero-lateral thigh, rectus, tensor facia lata, lattisimus dorsi, deep inferior epigastric artery perforator, and deep circumflex iliac artery flap. Radial artery forearm flaps and anterolateral thigh flaps were mostly used for burn contracture reconstructions. Twelve of the 13 (92%) fibulae were used for mandibular reconstruction for oral cancer and ameloblastoma. Rectus flaps were used mainly for covering defects over tibia. Hospital stay ranged from six to 67 days with an average of fourteen. Fifteen patients (26%) developed complications. The duration of operation ranged from six hours to 10.5 hours with an average of nine hours. The longest follow up was for four years. CONCLUSIONS: Microsurgery can be started even in very resource-poor center if there is support from advanced centers and if there is commitment of the institution and surgical team.

Advanced imaging technologies for mapping cadaveric lymphatic anatomy: magnetic resonance and computed tomography lymphangiography.

Lymphatic anatomy has become increasingly clinically important as surgical techniques evolve for investigating and treating cancer metastases. However, due to limited anatomical techniques available, research in this field has been insufficient. The techniques of computed tomography (CT) and magnetic resonance (MR) lymphangiography have not been described previously in the imaging of cadaveric lymphatic anatomy. This preliminary work describes the feasibility of these advanced imaging technologies for imaging lymphatic anatomy. A single, fresh cadaveric lower limb underwent lymphatic dissection and cannulation utilizing microsurgical techniques. Contrast materials for both CT and MR studies were chosen based on their suitability for subsequent clinical use, and imaging was undertaken with a view to mapping lymphatic anatomy. Microdissection studies were compared with imaging findings in each case. Both MR-based and CT-based contrast media in current clinical use were found to be suitable for demonstrating cadaveric lymphatic anatomy upon direct intralymphatic injection. MR lymphangiography and CT lymphangiography are feasible modalities for cadaveric anatomical research for lymphatic anatomy. Future studies including refinements in scanning techniques may offer these technologies to the clinical setting.

The role of the extensor digitorum communis muscle in lateral epicondylitis.

A common finding in tennis elbow is pain in the region of the lateral epicondyle during resisted extension of the middle finger (Maudsley's test). We hypothesized that the pain is due to disease in the extensor digitorum communis muscle, rather than to compression of the radial nerve or disease within extensor carpi radialis brevis. Thirteen human forearm specimens were examined. It was found that the extensor digitorum communis was separable into four parts. The part to the middle finger originated from the lateral epicondyle, but the muscle slips to the other fingers originated more distally. Pain ratings were measured in ten patients diagnosed with lateral epicondylitis during isometric finger and wrist extension tests. The results confirmed the high prevalence of a positive Maudsley's test in lateral epicondylitis, and also that the patients with tenderness at the site of origin of the extensor digitorum communis slip to the middle finger had the greatest pain during middle finger extension. These anatomical and clinical findings clarify the anatomy of extensor digitorum communis, and suggest that this muscle forms the basis for the Maudsley's test. The muscle may play a greater role in tennis elbow than previously appreciated.

Fig-eating by vertebrate frugivores: a global review.

The consumption of figs (the fruit of Ficus spp.: Moraceae) by vertebrates is reviewed using data from the literature, unpublished accounts and new field data from Borneo and Hong Kong. Records of frugivory from over 75 countries are presented for 260 Ficus species (approximately 30% of described species). Explanations are presented for geographical and taxonomic gaps in the otherwise extensive literature. In addition to a small number of reptiles and fishes, 1274 bird and mammal species in 523 genera and 92 families are known to eat figs. In terms of the number of species and genera of fig-eaters and the number of fig species eaten we identify the avian families interacting most with Ficus to be Columbidae, Psittacidae, Pycnonotidae, Bucerotidae, Sturnidae and Lybiidae. Among mammals, the major fig-eating families are Pteropodidae, Cercopithecidae, Sciuridae, Phyllostomidae and Cebidae. We assess the role these and other frugivores play in Ficus seed dispersal and identify fig-specialists. In most, but not all, cases fig specialists provide effective seed dispersal services to the Ficus species on which they feed. The diversity of fig-eaters is explained with respect to fig design and nutrient content, phenology of fig ripening and the diversity of fig presentation. Whilst at a gross level there exists considerable overlap between birds, arboreal mammals and fruit bats with regard to the fig species they consume, closer analysis, based on evidence from across the tropics, suggests that discrete guilds of Ficus species differentially attract subsets of sympatric frugivore communities. This dispersal guild structure is determined by interspecific differences in fig design and presentation. Throughout our examination of the fig-frugivore interaction we consider phylogenetic factors and make comparisons between large-scale biogeographical regions. Our dataset supports previous claims that Ficus is the most important plant genus for tropical frugivores. We explore the concept of figs as keystone resources and suggest criteria for future investigations of their dietary importance. Finally, fully referenced lists of frugivores recorded at each Ficus species and of Ficus species in the diet of each frugivore are presented as online appendices. In situations where ecological information is incomplete or its retrieval is impractical, this valuable resource will assist conservationists in evaluating the role of figs or their frugivores in tropical forest sites.

Genetic variation and structure in six Rhododendron species (Ericaceae) with contrasting local distribution patterns in Hong Kong, China.

Genetic variability of six rhododendrons with contrasting local distribution patterns in Hong Kong was assessed by starch gel electrophoresis. Rhododendron championiae, R. hongkongense and R. simiarum are locally rare with disjunct distributions, R. moulmainense is restricted and R. farrerae and R. simsii are common. For each species, 13-18 allozyme loci representing 12-16 enzyme systems were scored. The six species showed similar levels of genetic variations (HT ranged from 0.209 to 0.386 and AT ranged from 2.4 to 4.1) which are high compared to plants with similar life history traits. Genetic structure, in contrast, varied greatly between species, with FST ranging from 0.056 to 0.393. The three rarest species had high genetic differentiation (FST and FPT) and distinct geographical patterns, while the other three had low differentiation and little or no geographical structure. These differences are attributed to both present distributions and historical changes following deforestation within the last 1000 years. The conservation implications of these results are discussed.

Seed dispersal by long-tailed macaques.

We review here the methods by which long-tailed macaques (Macaca fascicularis fascicularis) process seeds in Bukit Timah Nature Reserve, Singapore, and the factors that influence this. Feeding observations have revealed that these macaques either destroy seeds in their mouth with their teeth, spit them out whole from the mouth after removing much of the flesh, or else clean the flesh off them at the front of the mouth and then drop them. Absence of these observed behaviors is associated with the presence of intact seeds in the feces, indicating that macaques swallow some seeds whole. All these options were exhibited by one group of macaques and were not random alternatives; evidence links their frequency to the type of fruit (fleshy vs. dry) and the size of the seed(s). Adaptations of the mouth of long-tailed macaques, such as gape and the presence of well-innervated cheek pouches and relatively large incisor and postcanine teeth, are predicted to influence these thresholds strongly. In a faunally depleted reserve like Bukit Timah, this dispersal is effective, but we see no evidence in this of coevolution between macaques and fruits. Many seeds in the macaque diet are probably dispersed more effectively by other vertebrates, such as birds, bats, gibbons, and civets, when these are present. However, in sites where large vertebrates have been eliminated, macaques may become important for dispersing large, large-seeded fruits.

Frugivory and seed dispersal by vertebrates in the Oriental (Indomalayan) Region.

Current knowledge of frugivory and seed dispersal by vertebrates in the Oriental Region is summarized. Some degree of frugivory has been reported for many fish and reptile species, almost half the genera of non-marine mammals and more than 40% of bird genera in the region. Highly frugivorous species, for which fruit dominates the diet for at least part of the year, occur in at least two families of reptiles, 12 families of mammals and 17 families of birds. Predation on seeds in fleshy fruits is much less widespread taxonomically: the major seed predators are colobine monkeys and rodents among the mammals, and parrots, some pigeons, and finches among the birds. Most seeds in the Oriental Region, except near its northern margins, are dispersed by vertebrate families which are endemic to the region or to the Old World. Small fruits and large, soft fruits with many small seeds are consumed by a wide range of potential seed dispersal agents, including species which thrive in small forest fragments and degraded landscapes. Larger, bigger-seeded fruits are consumed by progressively fewer dispersers, and the largest depend on a few species of mammals and birds which are highly vulnerable to hunting, fragmentation and habitat loss.

Focal tenosynovial amyloid deposition as a rare cause of median nerve compression at the wrist.

Although certain local and systemic aetiologies for the carpal-tunnel syndrome are known, a large number of cases of this syndrome do not have a conclusive aetiology. We present a case of histologically proven focal tenosynovial deposition of amyloid presenting as a rare cause of median nerve compression at the wrist.

The conservation value of small, isolated fragments of lowland tropical rain forest.

Deforestation is occurring at an alarming rate in the lowland tropics. In many tropical regions, rain forest is restricted to small (<100 ha), isolated fragments. While only the preservation of large areas of tropical rain forest can safeguard the complete biota, recent research has shown that a substantial number of forest species can persist for decades in fragmented forest, though large vertebrates are susceptible to habitat fragmentation. Inevitably, small fragments will become the last refuges of many rainforest species that are on the brink of extinction. In areas with little rain forest remaining, fragments can be the 'seeds' from which to re-establish extensive forest.

An anatomic review of the delay phenomenon: II. Clinical applications.

This paper applies the anatomic concepts and data obtained from our animal experimental studies of the delay phenomenon to a series of clinical cases. Similar clinical results were obtained to those seen in Part I of our study when skin flaps were raised with and without a delay, when a tissue expander was used, and when the delay technique was extended to musculocutaneous flaps. In each instance, the cutaneous perforators were identified with the Doppler probe to facilitate the delay of specific vessels rather than dividing those at random. Intraoperative arteriograms and venograms reveal that the choke arteries dilate and the anatomically unfavorable valved vein segments become regurgitant. The end result is the observation that at least one additional anatomic vascular territory can be added to the length of a flap with safety following a surgical delay.

Alternative seed-handling strategies in primates: seed-spitting by long-tailed macaques (Macaca fascicularis).

The seeds in fruits consumed by primates may be chewed and digested, swallowed and defecated intact, or separated from the flesh and spat out. We show by a combination of close field observations and experiments with caged animals, that long-tailed macaques (Macaca fascicularis) have a remarkably low threshold of 3-4 mm for swallowing seeds and also that wild macaques rarely break them. The seeds of 69% of the ripe fruit species eaten are spat out intact or cleaned outside the mouth and dropped. Seed-spitting significantly reduces the swallowed food bulk and may lessen the risk of releasing seed toxins during mastication. However, it requires that even small fruits are processed in the mouth one or a few at a time. We suggest that fruit storage in the cheek pouches of cercopithecine monkeys allows them to spit seeds individually without excessively slowing fruit intake while feeding on patchily distributed fruit. In contrast, Apes and New World monkeys apparently swallow and defecate most ripe seeds in their diet and colobine monkeys break and digest them, detoxifying seed defenses by bacterial fermentation.

Effects of obesity on insulin sensitivity and responsiveness in sheep.

To assess the mechanisms of insulin resistance in the ruminant, severe and adult-onset obesity was produced in Dorset ewes by overfeeding a high-energy ration over a 1- to 2-yr period. Body weights increased to 100 kg compared with 50 kg in lean control sheep; significant hyperinsulinemia (40 +/- 4 vs 10 +/- 1 microU/ml) also developed as did a moderate hyperglycemia (62 +/- 2 vs. 52 +/- 1 mg/100 ml). Tissue sensitivity and responsiveness to insulin were then determined in both obese and lean sheep by the euglycemic glucose-clamp technique. Insulin was infused at eight different rates from 0.2 to 50 mU.kg-1.min-1 and [6-3H]-glucose was infused for measurement of glucose kinetics. The mean dose-response curves for glucose utilization and clearance rates were displaced to the right in obese compared with lean sheep. As a result, the half-maximally effective insulin concentrations usually were elevated two- to fourfold, indicating decreased insulin sensitivity in obese sheep, and this is consistent with decreased insulin receptors in peripheral tissues. On the basis of fat-free body weight, the maximal glucose responses, however, were not significantly different between obese and lean sheep, indicating that postreceptor defects do not exist in muscle tissue. Furthermore, lean ruminants are more resistant to insulin than are humans, but this resistance seems only because of the sheep's decreased responsiveness to insulin and thus only because of postreceptor insulin effects in peripheral tissues.

The anterior tibial vessels and their role in epiphyseal and diaphyseal transfer of the fibula: experimental study and clinical applications.

The blood supply to the fibula from the anterior tibial and peroneal arteries was investigated in 66 fresh cadaver limbs by India ink injection and radiographic studies. These studies revealed a reliable blood supply to the proximal epiphysis and the proximal two-thirds of the diaphysis of the fibula from the anterior tibial artery. Although the peroneal artery provided the dominant supply to the shaft of the bone, its contribution to the head of the fibula was scanty. The cutaneous supply of each vessel was defined and correlated with the territories of the other vessels supplying the leg. The vascular anatomy of the leg was examined in 100 clinical angiograms, revealing 21 limbs with anomalies. This reinforces the case for preoperative angiogram studies where transfer of the fibula is contemplated. The technique of harvesting the proximal growth plate and the shaft of the fibula on the anterior tibial vessels alone is described and illustrated with two successful clinical cases, each followed for 4 years. The growth rate of the transferred epiphysis averaged 1 cm per year.

Patterns of immunoenhancement and suppression induced by Chlamydia trachomatis in vivo and in vitro.

We investigated the cycle of immune enhancement and suppression seen in mice infected with Chlamydia trachomatis by using in vivo and in vitro model systems. BALB/c mice injected intravenously with chlamydia reveal a three- to seven-fold increase in numbers of plaque-forming cells producing antibodies against sheep red blood cells (SRBC), when immunized with SRBC 0 to 5 days after chlamydia infection. When mice are injected with SRBC 10 to 15 days after initial chlamydia infection, the specific anti-SRBC plaque-forming cell response is suppressed two- to three-fold. In vitro, low numbers (2 to 5 X 10(6) bacteria/ml) of chlamydia stimulate potent proliferative responses by B lymphocytes while high numbers (25 X 10(6) bacteria/ml) of bacteria generate strong, general T suppressor activity. This model has important implications for regulation of immune responses that arise at different times during chlamydial infections, as well as for the potential effectiveness of chlamydial vaccines.

The versatile deep inferior epigastric (inferior rectus abdominis) flap.

The deep inferior epigastric vascular system nourishes a vast area of the anterior abdominal wall and offers a versatile variety of tissue combinations to the reconstructive surgeon for local or free flap transfer. Its supply to and beyond the rectus abdominis muscle provides the basis for flap design. Eighteen cases are presented to illustrate various muscle, myocutaneous and myosubcutaneous flaps that have been used to date to repair defects in the extremities and in the head and neck. The ease of dissection, coupled with the large calibre and length of the vascular stem, are key factors which combine to offer a speedy and a reliable technique. The donor site scar has been improved by the use of a suprapubic transverse incision to dissect the pedicle and this exposure provides access to the iliac crest for bone grafts where indicated. Time will evaluate this technique and further designs and modifications will undoubtedly be forthcoming. Meanwhile the initial results have been most promising.