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To examine the effectiveness of antithrombotic medications to prevent venous stent malfunction for iliocaval occlusive disease. A retrospective analysis was performed on 62 patients who underwent technically successful endovascular iliocaval stent placement between May 2008 and April 2017. Clinical records were reviewed for demographic information, procedure details, post-stenting antithrombotic prophylaxis and stent patency on follow-up. Stent malfunction was defined as > 50% stenosis or occlusion at follow-up. Risk factors for stent malfunction were assessed with univariable and multiple Cox proportional hazard models. The median follow-up period was 11.6 months (range 0.1–76.4). Overall primary and secondary cumulative patency rates at 12 months were 70.0% and 92.4%, respectively. After stent placement, 97% of patients received anticoagulation with warfarin, enoxaparin or a factor Xa inhibitor. In addition, 61% received antiplatelet prophylaxis with aspirin, clopidogrel or a combination. In multiple Cox regression analysis, post-stenting antiplatelet use remained significantly associated with primary stent patency (HR = 0.28, P = 0.022). After iliocaval venous stenting, stent patency was best predicted by concomitant antiplatelet and anticoagulation therapy rather than anticoagulation alone. This novel finding warrants further research underlying mechanisms leading to venous stent thrombosis, and has implications for optimal medical management after venous stenting.

in addressing the question of whether human prefrontal cortex (PFC) is “disproportionately larger in humans compared with nonhuman primates” in their article in PNAS, Donahue et al. (1) gloss over the distinction between proportional and relative size. Agreeing with previous work (2⇓–4), they show that PFC occupies a larger proportion of the cerebral cortex in humans than in chimpanzees and a larger proportion in chimpanzees than in macaques. Contrary to their presentation of the debate, this fact is uncontroversial. However, proportional size is often a misleading functional metric because of nonlinear, or allometric, scaling: A biological structure can differ across species as a proportion of overall size and yet be functionally equivalent (5) (Fig. 1). PFC volume proportion is predictable from overall brain size, even among nonhuman species (2⇓–4). This increase in volume proportions may be a scaling effect, with no consequences for functional influence exerted by PFC if there are different scaling constraints on different cortical regions (6). For example, disproportionate PFC white matter volume and cell size increases may be necessary to maintain long-range neural connectivity and neural transmission speed in larger brains and bodies (4, 6, 7). Indeed, this is consistent with Donahue et al.’s observation that white matter largely explains the species differences they observe in PFC proportional volume.

While the human brain is clearly large relative to body size, less is known about the timing of brain and brain component expansion within primates and the relative magnitude of volumetric increases. Using Bayesian phylogenetic comparative methods and data for both extant and fossil species, we identified that a distinct shift in brain-body scaling occurred as hominins diverged from other primates, and again as humans and Neanderthals diverged from other hominins. Within hominins, we detected a pattern of directional and accelerating evolution towards larger brains, consistent with a positive feedback process in the evolution of the human brain. Contrary to widespread assumptions, we found that the human neocortex is not exceptionally large relative to other brain structures. Instead, our analyses revealed a single increase in relative neocortex volume at the origin of haplorrhines, and an increase in relative cerebellar volume in apes., eLife digest Humans have much larger brains than other primates, but it is not clear exactly when and how this difference emerged during evolution. Some scientists believe that the expansion of a part of the brain called the neocortex – which handles sight, hearing, conscious decision-making and language – drove the increase in the size of the human brain. Newer studies have challenged that idea. One way to learn more about how humans evolved bigger brains is to compare the size of the brain, and specific parts of the brain, between humans and our closest relatives: non-human primates. To make accurate comparisons, scientists must account for many factors. Closely related primates may have more similar traits because they more recently shared a common ancestor. This means the evolutionary relationships between species need to be considered. Larger animals also tend to have larger brains so it is important to consider body size, too. Now, Miller at al. show that the human brain is much larger than expected even after accounting for these factors, and that increases in brain size accelerated over the course of early human evolution. In the analyses, the brain and skull sizes of different living primate species, like chimpanzees and gorillas, and fossils of extinct primates, including Neanderthals, were compared using mathematical models. These findings suggest that larger brains provided fitness advantages that led to large brain sizes in modern humans and Neanderthals. These increases in brain size were not driven by disproportionate growth in the neocortex alone, but rather by increases in the size of many parts of the brain. Increases in the relative size of the cerebellum, which is essential for balance and movement, were also important.

OBJECTIVE. Transjugular intrahepatic portosystemic shunt (TIPS) creation increases the risk of hepatic encephalopathy due to overshunting. Techniques exist to secondarily reduce the shunt for refractory encephalopathy. The purpose of this article is to describe a technique for primary TIPS restriction using a balloon-expandable stent within the transvenous hepatic track followed by deployment of a self-expanding polytetrafluoroethylene–lined stent-graft within the balloon-expandable stent to create the TIPS. CONCLUSION. This technique enables control over the degree of portosystemic shunting in elective TIPS creation.

Life history is a robust correlate of relative brain size: large-brained mammals and birds have slower life histories and longer lifespans than smaller-brained species. One influential adaptive hypothesis to account for this finding is the Cognitive Buffer Hypothesis (CBH). The CBH proposes that large brains permit greater behavioural flexibility and thereby buffer the animal from unpredictable environmental challenges, allowing reduced mortality and increased lifespan. In contrast, the Developmental Costs Hypothesis (DCH) suggests that life-history correlates of brain size reflect the extension of maturational processes needed to accommodate the evolution of large brains. The hypotheses are not mutually exclusive but do make different predictions. Here we test novel predictions of the hypotheses in primates: examining how the volume of brain components with different developmental trajectories correlate with relevant phases of maternal investment, juvenile period and post-maturational lifespan. Consistent with the DCH, structures with different allocations of growth to pre-natal versus post-natal development exhibit predictably divergent correlations with the associated periods of maternal investment and pre-maturational lifespan. Contrary to the CBH, adult lifespan is uncorrelated with either whole brain size or the size of individual brain components once duration of maternal investment is accounted for. Our results substantiate and elaborate on the role of maternal investment and offspring development in brain evolution, suggest that brain components can evolve partly independently through modifications of distinct developmental mechanisms, and imply that postnatal maturational processes involving interaction with the environment may be particularly crucial for the development of cerebellar function. They also provide an explanation for why apes have relatively extended maturation times, which relate to the relative expansion of the cerebellum in this clade.

One of the most pervasive assumptions about human brain evolution is that it involved relative enlargement of the frontal lobes. We show that this assumption is without foundation. Analysis of five independent data sets using correctly scaled measures and phylogenetic methods reveals that the size of human frontal lobes, and of specific frontal regions, is as expected relative to the size of other brain structures. Recent claims for relative enlargement of human frontal white matter volume, and for relative enlargement shared by all great apes, seem to be mistaken. Furthermore, using a recently developed method for detecting shifts in evolutionary rates, we find that the rate of change in relative frontal cortex volume along the phylogenetic branch leading to humans was unremarkable and that other branches showed significantly faster rates of change. Although absolute and proportional frontal region size increased rapidly in humans, this change was tightly correlated with corresponding size increases in other areas and whole brain size, and with decreases in frontal neuron densities. The search for the neural basis of human cognitive uniqueness should therefore focus less on the frontal lobes in isolation and more on distributed neural networks.

Commentary on Herculano-Houzel S (2015): Decreasing Sleep Requirement with Increasing Numbers of Neurons as a Driver for Bigger Brains and Bodies in Mammalian Evolution. Proc Biol Sci 282:20151853

Purpose To describe the use of intravascular ultrasound (US) guidance for creation of transjugular intrahepatic portosystemic shunts (TIPSs) in humans. Materials and Methods The initial 25 cases of intravascular US–guided TIPS were retrospectively compared versus the last 75 conventional TIPS cases during the same time period at the same institution in terms of the number of needle passes required to establish portal vein (PV) access, fluoroscopy time, and needle pass–related complications. Results Intravascular US–guided TIPS creation was successful in all cases, and there was no statistically significant difference in number of needle passes, fluoroscopy time, or needle pass–related complications between TIPS techniques. Intravascular US–guided TIPS creation was successful in cases in which conventional TIPS creation had failed as a result of PV thrombosis or distorted anatomy. Intravascular US guidance for TIPS creation was additionally useful in a patient with Budd–Chiari syndrome and in a patient with intrahepatic tumors. Conclusions Intravascular US is a safe and reproducible means of real-time image guidance for TIPS creation, equivalent in efficacy to conventional fluoroscopic guidance. Real-time sonographic guidance with intravascular US may prove advantageous for cases in which there is PV thrombus, distorted anatomy, Budd–Chiari syndrome, or hepatic tumors.

Much attention has focused on the dramatic expansion of the forebrain, particularly the neocortex, as the neural substrate of cognitive evolution. However, though relatively small, the cerebellum contains about four times more neurons than the neocortex. I show that commonly used comparative measures such as neocortex ratio underestimate the contribution of the cerebellum to brain evolution. Once differences in the scaling of connectivity in neocortex and cerebellum are accounted for, a marked and general pattern of correlated evolution of the two structures is apparent. One deviation from this general pattern is a relative expansion of the cerebellum in apes and other extractive foragers. The confluence of these comparative patterns, studies of ape foraging skills and social learning, and recent evidence on the cognitive neuroscience of the cerebellum, suggest an important role for the cerebellum in the evolution of the capacity for planning, execution and understanding of complex behavioural sequences—including tool use and language. There is no clear separation between sensory–motor and cognitive specializations underpinning such skills, undermining the notion of executive control as a distinct process. Instead, I argue that cognitive evolution is most effectively understood as the elaboration of specialized systems for embodied adaptive control.

The anatomical basis and adaptive function of the expansion in primate brain size have long been studied; however, we are only beginning to understand the genetic basis of these evolutionary changes. Genes linked to human primary microcephaly have received much attention as they have accelerated evolutionary rates along lineages leading to humans. However, these studies focus narrowly on apes, and the link between microcephaly gene evolution and brain evolution is disputed. We analyzed the molecular evolution of four genes associated with microcephaly (ASPM, CDK5RAP2, CENPJ, MCPH1) across 21 species representing all major clades of anthropoid primates. Contrary to prevailing assumptions, positive selection was not limited to or intensified along the lineage leading to humans. In fact we show that all four loci were subject to positive selection across the anthropoid primate phylogeny. We developed clearly defined hypotheses to explicitly test if selection on these loci was associated with the evolution of brain size. We found positive relationships between both CDK5RAP2 and ASPM and neonatal brain mass and somewhat weaker relationships between these genes and adult brain size. In contrast, there is no evidence linking CENPJ and MCPH1 to brain size evolution. The stronger association of ASPM and CDK5RAP2 evolution with neonatal brain size than with adult brain size is consistent with these loci having a direct effect on prenatal neuronal proliferation. These results suggest that primate brain size may have at least a partially conserved genetic basis. Our results contradict a previous study that linked adaptive evolution of ASPM to changes in relative cortex size; however, our analysis indicates that this conclusion is not robust. Our finding that the coding regions of two widely expressed loci has experienced pervasive positive selection in relation to a complex, quantitative developmental phenotype provides a notable counterexample to the commonly asserted hypothesis that cis-regulatory regions play a dominant role in phenotypic evolution.

Magnetic resonance imaging of hyperpolarized nuclei provides high image contrast with little or no background signal. To date, in-vivo applications of pre-hyperpolarized materials have been limited by relatively short nuclear spin relaxation times. Here, we investigate silicon nanoparticles as a new type of hyperpolarized magnetic resonance imaging agent. Nuclear spin relaxation times for a variety of Si nanoparticles are found to be remarkably long, ranging from many minutes to hours at room temperature, allowing hyperpolarized nanoparticles to be transported, administered, and imaged on practical time scales. Additionally, we demonstrate that Si nanoparticles can be surface functionalized using techniques common to other biologically targeted nanoparticle systems. These results suggest that Si nanoparticles can be used as a targetable, hyperpolarized magnetic resonance imaging agent with a large range of potential applications.

Purpose: To evaluate the safety of inferior vena cava (IVC) filter retrieval in therapeutically anticoagulated patients in comparison to prophylactically or not therapeutically anticoagulated patients with respect to retrieval-related hemorrhagic complications. Materials and methods: This was a retrospective study of 115 consecutive attempted IVC filter retrievals in 110 patients. Filter retrievals were stratified as performed in patients who were therapeutically anticoagulated (group 1), prophylactically anticoagulated (group 2), or not therapeutically anticoagulated (group 3). The collected data included anticoagulant and antiplatelet medications (type, form and duration of administration, dosage) at the time of retrieval. Phone interviews and chart review was performed for the international normalized ratio (INR), activated partial thromboplastin time, platelet count, infusion of blood products, and retrievalrelated hemorrhagic complications. Results: Group 1 included 65 attempted filter retrievals in 61 therapeutically anticoagulated patients by measured INR or dosing when receiving low-molecular-weight heparin (LMWH). Four retrievals were not successful. In patients receiving oral anticoagulation, the median INR was 2.35 (range, 2 to 8). Group 2 comprised 23 successful filter retrievals in 22 patients receiving a prophylactic dose of LMWH. Group 3 included 27 attempted filter retrievals in 27 patients not receiving therapeutic anticoagulation. Six retrievals were not successful. Five patients were receiving oral anticoagulation with a subtherapeutic INR (median, 1.49; range, 1.16 to 1.69). No anticoagulation medication was administered in 22 patients. In none of the groups were hemorrhagic complications related to the retrieval procedures identified. Conclusions: These results suggest that retrieval of vena cava filters in anticoagulated patients is safe. Interruption or reversal of anticoagulation for the retrieval of vena cava filters is not indicated. (CHEST 2007; 132:31–36)

Endoscopic surgical applications of erbium lasers have been limited due to the lack of a suitable mid-IR optical fiber delivery system. Germanium oxide fibers are used for noncontact tissue ablation, but are not recommended for contact tissue ablation applications typically required during endoscopic surgery. This study describes the assembly and characterization of hybrid mid-IR fibers consisting of germanium oxide trunk fibers and sapphire fiber tips, and side-firing germanium oxide fibers with either 45deg angled tips or micromirrors. Average powers up to 8.5 W (850 mJ at 10 Hz) and transmission up to 70% was demonstrated through 450-mum-core, 1.5-m-long fibers, sufficient for endoscopic laser ablation of soft and hard tissues in contact mode.

Prenatal androgens are responsible for sex differences in behaviour and morphology in many species, causing changes in neural structure and function that persist throughout life. Some variation in the expression of behaviour between individuals of the same sex can also be attributed to differences in exposure to prenatal sex hormones. The ratio of the second and fourth digits (2D:4D ratio) is a proposed biomarker for prenatal androgen effects (PAE). Through assessment of 2D:4D ratios, this study aimed to investigate the relationship between inferred PAE and social behaviours in female chacma baboons (Papio ursinus). We validated a new method to measure 2D:4D indirectly using digital photographs and computer-assisted image analysis software. There was a strong correlation between 2D:4D ratio and dominance rank amongst female baboons. Low 2D:4D ratios were associated with high rank, lower submission rates and higher rates of non-contact and contact aggression. This is consistent with the hypothesis that prenatal androgens are linked to the expression of these behaviours in female baboons, although it was not possible to separate the effects of PAE and dominance rank on some rank-related behaviours. The 2D:4D ratio did not correlate with interest in infants or with the rate of affiliative behaviours, possibly because these behaviours are more affected by ovarian hormones in adult life than by PAE. Finally, mean 2D:4D ratios were positively correlated in six mother/infant pairs, consistent with a heritable basis for the 2D:4D ratio in primates. We suggest that PAE contribute significantly to the patterning of social relationships in female primates.

The hypothesis that play behavior is more prevalent in larger-brained animals has recently been challenged. It may be, for example, that only certain brain structures are related to play. Here, we analyze social play behavior with regards to the cerebellum: a structure strongly implicated in motor-development, and possibly also in cognitive skills. We present an evolutionary analysis of social play and the cerebellum, using a phylogenetic comparative method. Social play frequency and relative cerebellum size are positively correlated. Hence, there appears to be a link between the evolutionary elaboration of social play and the cerebellum.

The United States (US) Environmental Protection Agency (EPA) estimated that the use of technical grade pentachlorophenol (PCP) between 1970 and 1995 to treat wood was approximately 400 000 metric tons in the US, and that between 4800 and 36 000 g of 2,3,7,8-tetrachlorodibenzo- p -dioxin toxic equivalents (TEQs) were incorporated annually in treated wood. The EPA has been unable, however, to estimate the rate of release of polychlorinated dibenzo -p- dioxins and dibenzofurans (CDD/Fs) from treated utility poles into the environment. There is some evidence that CDD/Fs leach from treated poles into the surrounding soils, but these studies do not allow for the calculation of a rate of release from this mechanism. Another possible release mechanism is the volatilization of dioxins into the atmosphere, but there are no data to demonstrate, much less quantify, this release. While not directly measuring the release of dioxins from treated utility poles into the environment, this study was designed to examine the potential for such release. The general approach taken was to collect PCP-treated poles of varying ages, to remove and analyze multiple samples from each pole cross-section, and to compare the spatial distribution of CDD/F congeners among poles of different ages. Evidence of concentration–depth profile changes over time may provide insight into the potential for dioxins to migrate through and then out of PCP-treated utility poles. It was found that the CDD/F concentrations were consistently higher in the outer portions of the poles than the center. This trend tends to be most marked in older poles and for the lower chlorinated congeners. The trend for dioxins to concentrate in the outer portions of the pole over time suggest migration within the poles, and this migration may result in some environmental release. Other possible explanations were also offered.

A previously healthy 27-year-old woman (gravida 2 para 1) presented in the 42nd week of an otherwise ordinary pregnancy with right flank pain radiating to the groin. Membranes were intact, the cervix was long and closed, and no uterine contractions were present. Fundal height was appropriate (40 cm) and fetal assessment was unremarkable. She was afebrile with mild tachycardia (117 bpm) and was extremely tender in the right flank. Routine laboratory tests were within normal limits except for the urinalysis, which revealed 31 RBC. She was admitted to the labor and delivery unit for intravenous hydration with a presumed diagnosis of right renal colic. Within a few hours of admission, the flank pain evolved into generalized abdominal pain and physical examination revealed marked abdominal tenderness. Simultaneously, fetal heart tracings began to show ominous decelerations and loss of variability, prompting an emergency delivery for suspected placental abruption. In the operating room, a live male fetus weighing 7 lb 14 oz. was delivered by cesarean section (APGAR, 7/9). Placental abruption was not confirmed. Rather, inspection of the maternal abdomen revealed a hemoperitoneum of approximately 200 cm which was clotted and dark in color. A retroperitoneal hematoma was identified inferior to the liver which appeared to be the source of the intraperitoneal blood. No active bleeding was observed, so the abdomen was closed. However, her postoperative hematocrit level of 16.8% was lower than anticipated for the combined operative blood loss and hemoperitoneum (her hematocrit level on admission was 32.8%). A total of six units of blood were transfused postoperatively as the patient’s hematocrit level decreased on two further occasions. Computed tomography (CT) of the abdomen was performed to confirm the presence of a retroperitoneal hemorrhage on the right side as seen at surgery.

Studies of postconflict behavior have focused on Old World primates, particularly on members of the cercopithecines and chimpanzees. We present data on patterns of reconciliation in two captive groups of spectacled leaf monkeys, members of the Colobinae. Reconciliation occurred at a high rate relative to that in other primate species and within the first minute following a conflict. Friendly postconflict contact was usually initiated by aggressors in one group, and by recipients in the other. But, there was no difference in postconflict initiative to contact in comparison with MCs. These two groups showed behavioral specificity in the context of postconflict reunions. Ventroventral embracing was a common, explicit (de Waal, 1993) form of reconciliation. The intensity of aggression and situations in which the victim responded aggressively had no effect on the likelihood of reconciliation occurring. The postconflict behavior of both groups lends further support to the relationship-quality hypothesis (Aureli et al., 1989). Kinship and rank distance and had no effect on reconciliation, though affiliation levels correlated positively with the tendency to reconcile. These results indicate that spectacled langurs are among the more tolerant of the species studied so far.

We studied the postconflict interactions with group members other than the former opponent in two groups of spectacled leaf monkeys. We found no evidence of redirection of aggression towards other group members. Victims and aggressors sought affiliative contacts with uninvolved third parties. There was no evidence for consolation—affiliative contact initiated by an uninvolved third party, directed towards victims of aggression—in either group when all affiliative behaviors were considered. However, embracing was a characteristic first-contact interaction between individuals involved in aggression and third parties. This finding mirrors the results concerning reconciliation in spectacled leaf monkeys. Accordingly, embracing may be a true consolatory behavior in this species. When contacts with third parties occurred before or in the absence of reconciliation, the timing of such contacts fell within the time window during which reconciliation normally occurs. These contacts also resulted in affiliation levels twice that of baseline levels, supporting the idea that these contacts may function as a form of substitute reconciliation. We discuss these results in light of recent theories concerning postconflict behavior in primates.

The mammalian brain comprises a number of functionally distinct systems. It might therefore be expected that natural selection on particular behavioural capacities would have caused size changes selectively, in the systems mediating those capacities. It has been claimed, however, that developmental constraints limited such mosaic evolution, causing co-ordinated size change among individual brain components. Here we analyse comparative data to demonstrate that mosaic change has been an important factor in brain structure evolution. First, the neocortex shows about a fivefold difference in volume between primates and insectivores even after accounting for its scaling relationship with the rest of the brain. Second, brain structures with major anatomical and functional links evolved together independently of evolutionary change in other structures. This is true at the level of both basic brain subdivisions and more fine-grained functional systems. Hence, brain evolution in these groups involved complex relationships among individual brain components.

Several theories have been proposed to explain the evolution of species differences in brain size, but no consensus has emerged. One unresolved question is whether brain size differences are a result of neural specializations or of biological constraints affecting the whole brain. Here I show that, among primates, brain size variation is associated with visual specialization. Primates with large brains for their body size have relatively expanded visual brain areas, including the primary visual cortex and lateral geniculate nucleus. Within the visual system, it is, in particular, one functionally specialized pathway upon which selection has acted: evolutionary changes in the number of neurons in parvocellular, but not magnocellular, layers of the lateral geniculate nucleus are correlated with changes in both brain size and ecological variables (diet and social group size). Given the known functions of the parvocellular pathway, these results suggest that the relatively large brains of frugivorous species are products of selection on the ability to perceive and select fruits using specific visual cues such as colour. The separate correlation between group size and visual brain evolution, on the other hand, may indicate the visual basis of social information processing in the primate brain.

An inadvertent case of pericardial placement of a central venous catheter was successfully treated by direct thrombin injection.

To prospectively evaluate the clinical efficacy of polyethylene-covered metallic Z-stents in treatment of dysphagia secondary to malignant esophageal obstruction and esophagorespiratory fistula.Thirty-five patients with dysphagia due to malignant esophageal obstruction (n = 32) and esophagorespiratory fistula (n = 3) were treated with polyethylene-covered Gianturco-Rösch Z-stents.Thirty-nine stents were placed in 35 patients. Stent placement was technically successful in all patients. Improvement in dysphagia was achieved in 34 of 35 patients. The average dysphagia score decreased from 3.1 (dysphagia to liquids) to 0.6 (essentially normal diet). An esophagorespiratory fistula was completely sealed in two of three patients. All 35 patients were followed up clinically at 1 day and 1 week and at 3-month intervals (range, 1 week to 18 1/2 months; mean, 4.8 months). Recurrent dysphagia or aspiration occurred in only three of 34 (9%) patients whose disease was initially palliated and was easily treated in all cases. Nine complications occurred in eight patients (23%) and included chest pain that required analgesia (n = 3), food impaction (n = 1), stent migration (n = 2), and upper gastrointestinal tract hemorrhage (n = 3).Polyethylene-covered stents are a relatively safe and effective means of long-term palliation in patients with severe malignant esophageal obstruction and esophagorespiratory fistula. These stents are easily deployed, and the rate of stent migration is relatively low.

We describe two cases of airway foreign bodies (FB) consisting of a dental crown. The shape and composition of dental crowns complicate their extraction from the tracheobronchial tree, sometimes necessitating thoracotomy. We describe the use of a multidisciplinary approach involving rigid and flexible bronchoscopy in concert with the use of wire snares under fluoroscopic guidance for extraction of these challenging FB. These cases illustrate that this multidisciplinary approach can allow successful extraction of the difficult FB from much of the tracheobronchial tree and the avoidance of thoracotomy.

Background: Mediastinal malignancies may involve the esophagus, leading to esophageal stenosis and dysphagia. Rigid and self-expanding esophageal stents have been used for effective palliation, but their use in extrinsic, compressive lesions is controversial. Methods: A retrospective review of self-expanding Gianturco-Rosch Z-stents that were successfully placed in 13 patients with malignant esophageal obstruction due to extrinsic lesions. Results: All patients had an improvement in dysphagia of at least two dysphagia grades. The mean dysphagia grade fell from 3.15 to 0.62. Mean survival was 2.2 months. Early (within 48 hours) procedure-related complications occurred in 4 of 13 patients and consisted of minor, transient chest pain that resolved within 6 hours (3 patients) and endoscopic stent dislodgment into the stomach (1 patient). Late complications (>48 hours) occurred in 2 patients and consisted of a partial proximal stent migration and the development of a benign stricture proximal to the stent. There was no procedural or stent related mortality. Conclusions: Esophageal obstruction and malignant dysphagia from extrinsic, compressive mediastinal malignancies can be effectively and safely palliated with self-expanding Gianturco-Rosch Z-stents. (Gastrointest Endosc 1996;43:483-9.)

The neocortex is widely held to have been the focus of mammalian brain evolution, but what selection pressures explain the observed diversity in its size and structure? Among primates, comparative studies suggest that neocortical evolution is related to the cognitive demands of sociality, and here I confirm that neocortex size and social group size are positively correlated once phylogenetic associations and overall brain size are taken into account. This association holds within haplorhine but not strepsirhine primates. In addition, the neocortex is larger in diurnal than in nocturnal primates, and among diurnal haplorhines its size is positively correlated with the degree of frugivory. These ecological correlates reflect the diverse sensory-cognitive functions of the neocortex.

Purpose To evaluate expandable metallic Gianturco-Rosch Z (GRZ) stents for treatment of benign and malignant tracheobronchial stenoses. Patients and Methods Six patients, ages 45–73 years, were treated for severe dyspnea with placement of GRZ stents. Three patients had benign tracheal lesions (one tracheomalacia, two postoperative) and received uncovered GRZ stents. Three patients had malignant stenoses at the level of the carina; one received an uncovered stent and the other two received silicone-covered GRZ stents. Results Two patients with benign lesions responded well to stent placement. One was asymptomatic for a year and then was lost to follow-up; the other improved substantially but died of end-stage lung disease 5 months after stent placement. A third patient with a benign high tracheal lesion did poorly; symptoms recurred secondary to inferior migration of a stent, which was removed surgically at 4 months. All patients with malignant lesions improved symptomatically after stent placement and remained without significant dyspnea until death (from 1 to 6 months). Conclusion Expandable GRZ stents are promising devices for treatment of benign lesions and offer effective palliation of malignant tracheobronchial stenoses.

Esophagogastric malignancies often are manifested with progressive dysphagia or esophagorespiratory fistulas. Palliative modalities currently available have significant limitations. A modified Gianturco-Rosch silicone-covered self-expanding metallic Z stent was used in 32 consecutive patients with malignant esophageal obstruction (n =24) or esophagorespiratory fistulas (n = 8). The stent was placed successfully in all patients. Dysphagia improved by at least two grades in 21 of the 24 patients (87.5%); the mean dysphagia grade fell from 3.21 to 1.08. Six of the 8 patients with fistulas were able to resume a normal diet, and the other 2 were able to eat solids without symptoms of aspiration. Complications occurred in 10/32 patients (31%) and included stent migration (4 patients), food impaction (2 patients), membrane disruption with tumor ingrowth (1 patient), tumor overgrowth (1 patient), early pressure necrosis with hemorrhage (1 patient), and late pressure necrosis with sepsis (1 patient). The latter 2 patients died, giving a mortality rate of 6.3%. Many complications were managed with endoscopic or interventional radiologic techniques. Although randomized prospective clinical trials are needed, the silicone-covered Gianturco-Rosch Z stent offers promise for the effective palliation of malignant esophageal obstruction and esophagorespiratory fistulas. (Gastrontest Endosc 1994;40:22-33.)

Brain size variation in mammals correlates with life histories: larger-brained species have longer gestations, mature later, and have increased lifespans. These patterns have been explained in terms of developmental costs (larger brains take longer to grow) and cognitive benefits (large brains enhance survival and increase lifespan). In support of the developmental cost hypothesis, we show that evolutionary changes in pre- and postnatal brain growth correlate specifically with duration of the relevant phases of maternal investment (gestation and lactation, respectively). We also find support for the hypothesis that the rate of fetal brain growth is related to the energy turnover of the mother. In contrast, we find no support for hypotheses proposing that costs are accommodated through direct tradeoffs between brain and body growth, or between brain growth and litter size. When the duration of maternal investment is taken into account, adult brain size is uncorrelated with other life history traits such as lifespan. Hence, the general pattern of slower life histories in large-brained species appears to be a direct consequence of developmental costs.

The evolution of cognitive and sensory specializations must involve concomitant modifications of neural substrates. Ecological correlates of species differences in brain structure are intriguing sources of evidence about such evolutionary specialization but, to date, these have been identified only for gross parameters, such as overall brain size and the size of major brain regions. Here we show that a behavioural specialization in mammals, predation, is associated with species differences in the fine structure of a single neural pathway, the tectospinal tract. Both the relative number of neurons in this pathway and the relative size of their cell bodies were greater in more predatory species than in their less predatory counterparts within each of four separate mammalian orders. Expansion of these analyses to consider comparisons between taxa at a variety of taxonomic levels gave further support to the idea of a relation between predatory habits and the evolution of the tectospinal tract. In addition, within the primates, the number of neurons in the tectospinal tract was significantly correlated with the proportion of prey in the diet. These results therefore appear to provide an example of correlated evolution between a specific neural system and behaviour which applies generally within the mammals. They also help to unify findings from physiological and anatomical studies on a wider range of vertebrate taxa, including reptiles and amphibians.

The mammalian placenta exhibits striking interspecific morphological variation, yet the implications of such diversity for reproductive strategies and fetal development remain obscure. More invasive hemochorial placentas, in which fetal tissues directly contact the maternal blood supply, are believed to facilitate nutrient transfer, resulting in higher fetal growth rates, and to be a state of relative fetal advantage in the evolution of maternal-offspring conflict. The extent of interdigitation between maternal and fetal tissues has received less attention than invasiveness but is also potentially important because it influences the surface area for exchange. We show that although increased placental invasiveness and interdigitation are both associated with shorter gestations, interdigitation is the key variable. Gestation times associated with highly interdigitated labyrinthine placentas are 44% of those associated with less interdigitated villous and trabecular placentas. There is, however, no relationship between placental traits and neonatal body and brain size. Hence, species with more interdigitated placentas produce neonates of similar body and brain size but in less than half the time. We suggest that the effects of placental interdigitation on growth rates and the way that these are traded off against gestation length may be promising avenues for understanding the evolutionary dynamics of parentoffspring conflict.\ud \ud Keywords: placenta, parent-offspring conflict, life history, brain evolution, reproductive strategies, gestation.

Summary 1. Mammalian sleep is composed of two distinct states ‐ rapid-eye-movement (REM) and nonREM (NREM) sleep ‐ that alternate in cycles over a sleep bout. The duration of these cycles varies extensively across mammalian species. Because the end of a sleep cycle is often followed by brief arousals to waking, a shorter sleep cycle has been proposed to function as an anti-predator strategy. Similarly, higher predation risk could explain why many species exhibit a polyphasic sleep pattern (division of sleep into several bouts per day), as having multiple sleep bouts avoids long periods of unconsciousness, potentially reducing vulnerability. 2. Using phylogenetic comparative methods, we tested these predictions in mammals, and also investigated the relationships among sleep phasing, sleep-cycle length, sleep durations and body mass. 3. Neither sleep-cycle length nor phasing of sleep was significantly associated with three different measures of predation risk, undermining the idea that they represent anti-predator adaptations. 4. Polyphasic sleep was associated with small body size, shorter sleep cycles and longer sleep durations. The correlation with size may reflect energetic constraints: small animals need to feed more frequently, preventing them from consolidating sleep into a single bout. The reduced daily sleep quotas in monophasic species suggests that the consolidation of sleep into one bout per day may deliver the benefits of sleep more efficiently and, since early mammals were small-bodied and polyphasic, a more efficient monophasic sleep pattern could be a hitherto unrecognized advantage of larger size.

WHEN Ehrlich introduced arsphenamine (N. N. R.) in 1909 it was his sincere hope that syphilis could be cured with a single injection of the drug. It soon became apparent that one injection was woefully inadequate and, moreover, that three, six or even more injections failed to yield the desired result. With the introduction of bismuth as a powerful ally, the campaign against syphilis moved closer to its goal. Two decades after Ehrlich's discovery, following the admirable work of the Clinical Cooperative Group, 1 it was generally recognized that the use of alternating courses of the arsenicals and bismuth preparations, given continuously over a period of approximately twelve to eighteen months, in a large percentage of cases, gave the result which Ehrlich had sought in vain. In the early 1930's, a group of physicians 2 once again envisioned the possibility of eradicating syphilis in a short time by utilizing an

EVER since 1905, when Donovan 1 described the peculiar intracellular and extracellular encapsulated organisms which he found in fresh spreads taken from ulcerative lesions of granuloma inguinale, the nature of the Donovan body has excited great interest. Though Donovan himself expressed the opinion that the organism is a protozoan, its position in the field of toxonomy was a moot point, eliciting much labor but little light, until Anderson, DeMonbreun and Goodpasture 2 successfully cultivated the Donovan body in the yolk of chick embryos. According to these investigators the organism is a bacillus, for which they proposed the generic name "Donovania" and the specific name "granulomatis." The therapy of the disease was ineffective until 1913, when intravenous administration of antimony and potassium tartrate was introduced by de Beaurepaire, Aragao and Vianna. 3 This drug was enthusiastically acclaimed by Low and Newham, 4 Pardo, 5 and Randall, Small and Belk. 6 Fraser

TWO REPORTS have been published recently, 1 showing spectacularly favorable results in the prevention of prenatal syphilis with the use of penicillin in the treatment of syphilitic pregnant women. It is well known that mothers with syphilis which is beyond the infectious state may deliver normal nonsyphilitic children in a varying but large percentage of cases. Transmission of syphilis to the fetus occurs much more frequently when pregnant women have syphilis in the early infectious stages than in the later stages of the disease. The efficacy of any therapeutic procedure in preventing prenatal syphilis, therefore, will be evaluated most reliably by the effect on the offspring of mothers who during pregnancy had indisputable early infectious syphilis. When rigidly selected, the number of patients whom we saw who had proved infectious syphilis during pregnancy was limited. To obtain a satisfactory number of cases for evaluation it is necessary to compile the

Gianturco-Rösch expandable Z-stents were used in 22 patients with superior vena cava syndrome (SVCS). Stents were placed in all patients in the SVC and in 17 patients, also into the innominate veins. Stent placement resulted in complete relief of symptoms in all patients. Twenty-one patients had no SVCS recurrence from 1 to 16 months, to their death, or to the present time. SVCS recurred only in 1 patient 9 months after stent placement due to tumor ingrowth and secondary thrombosis. Based on ours and on other reported experiences, expandable metallic stents are effective devices for treatment of the SVCS which is difficult to manage by other means.

Sleep is a pervasive characteristic of mammalian species, yet its purpose remains obscure. It is often proposed that ‘sleep is for the brain’, a view that is supported by experimental studies showing that sleep improves cognitive processes such as memory consolidation. Some comparative studies have also reported that mammalian sleep durations are higher among more encephalized species. However, no study has assessed the relationship between sleep and the brain structures that are implicated in specific cognitive processes across species. The hippocampus, neocortex and amygdala are important for memory consolidation and learning and are also in a highly actived state during sleep. We therefore investigated the evolutionary relationship between mammalian sleep and the size of these brain structures using phylogenetic comparative methods. We found that evolutionary increases in the size of the amygdala are associated with corresponding increases in NREM sleep durations. These results are consistent with the hypothesis that NREM sleep is functionally linked with specializations of the amygdala, including perhaps memory processing.

Changes in neocortex size were a prominent feature of mammalian brain evolution, but the implications for cortical structure, and consequently for the functional significance of such changes in overall cortical size, are poorly understood. A basic question is whether functionally differentiated cortical areas evolved independently of one another (adaptive specialization) or were allometrically constrained to co-vary tightly with the size of the whole. Here, I provide comparative evidence for adaptive specialization of cortical structure. First, the sizes of individual areas differ significantly between taxa after controlling for overall cortical size. Second, an analysis of separate visual cortical areas reveals that these exhibit statistically correlated evolution, independent of variation in nonvisual areas. Third, visual cortex size exhibits correlated evolution with peripheral visual adaptations (eye morphology and optic nerve size) and with photic niche. Thus, the evolution of mammalian cortical structure was closely associated with specialization for different sensory niches.

Background Social and competitive demands often differ between the sexes in mammals. These differing demands should be expected to produce variation in the relative sizes of various brain structures. Sexual selection on males can be predicted to influence brain components handling sensory-motor skills that are important for physical competition or neural pathways involving aggression. Conversely, because female fitness is more closely linked to ecological factors and social interactions that enable better acquisition of resources, social selection on females should select for brain components important for navigating social networks. Sexual and social selection acting on one sex could produce sexual dimorphism in brain structures, which would result in larger species averages for those same brain structures. Alternatively, sex-specific selection pressures could produce correlated effects in the other sex, resulting in larger brain structures for both males and females of a species. Data are presently unavailable for the sex-specific sizes of brain structures for anthropoid primates, but under either scenario, the effects of sexual and social selection should leave a detectable signal in average sizes of brain structures for different species. Results The degree of male intra-sexual selection was positively correlated with several structures involved in autonomic functions and sensory-motor skills, and in pathways relating to aggression and aggression control. The degree of male intra-sexual selection was not correlated with relative neocortex size, which instead was significantly positively correlated with female social group size, but negatively correlated with male group size. Conclusion Sexual selection on males and social selection on females have exerted different effects on primate brain architecture. Species with a higher degree of male intra-sexual selection carry a neural signature of an evolutionary history centered on physical conflicts, but no traces of increased demands on sociocognitive tasks. Conversely, female sociality is indicated to have driven the evolution of socio-cognitive skills. Primate brain architecture is therefore likely to be a product of ecological and species-specific social factors as well as different sex-specific selection pressures. Our results also highlight the need for acquisition and analysis of sex-specific brain components in mammals.

Purpose To retrospectively review the indications and outcomes of transjugular liver biopsy (TJLB) with the left internal jugular vein (IJV) approach. Materials and methods A retrospective review of all TJLBs performed at one institution was performed. From August 1995 to October 2004, 293 liver biopsies were performed. Nineteen of the 293 procedures (6.5%) were performed from the left IJV in 17 patients. There were 11 men and six women aged 36–59 years (mean, 49.3 years). All patients were suspected of having diffuse hepatic parenchymal disease and had contraindications to conventional percutaneous liver biopsy. The stiff metal biopsy cannula was advanced across the mediastinum and through the heart over a stiff guide wire. Biopsy was performed from the right hepatic vein in 15 procedures, the middle hepatic vein in two, and the intrahepatic IVC in two. Results The indications for using the left IJV approach were nonusable right IJV in 12 procedures, difficult previous catheterization of the hepatic veins from the right IJV due to distorted hepatic anatomy in six procedures, and the operator’s predilection for this approach in one procedure (the patient had previously undergone liver transplantation). All biopsies were successful, with diagnostic tissue obtained in 100% of cases. Two patients had chest pain during the procedure associated with placement of the rigid cannula through the mediastinal veins. One patient had a vaso-vagal episode that necessitated the use of intravenous atropine but subsequently underwent successful biopsy. All episodes of chest pain resolved after the cannula was removed. There were no recorded hemorrhagic or cardiac complications. Conclusion TJLB can be safely and repeatedly performed from the left IJV when the right IJV is not available or the hepatic anatomy prevents catheterization of the hepatic veins from the right IJV.