Dextroamphetamine with morphine for the treatment of postoperative pain

In a double-blind, single-dose study, dextroamphetamine combined with morphine was compared with morphine alone to determine the relative efficacy of the combination given intramuscularly for postoperative pain. Each of 450 patients received one treatment of morphine sulfate (3, 6 or 12 mg) with dextroamphetamine (0, 5 or 10 mg). Analgesia, as measured by the patients' subjective responses to questions about relief of pain, was augmented when dextroamphetamine was given with morphine; the combination of dextroamphetamine, 10 mg, with morphine was twice as potent as morphine alone, and the combination with 5 mg was 1 1/2 times as potent as morphine. In simple performance tests, and in measures of side effects, dextroamphetamine generally offset undesirable effects of morphine (sedation and loss of alertness) while increasing analgesia. Effects on blood pressure, pulse and respiratory rate were minimal.

Island biogeography of the Anthropocene

For centuries, biogeographers have examined the factors that produce patterns of biodiversity across regions. The study of islands has proved particularly fruitful and has led to the theory that geographic area and isolation influence species colonization, extinction and speciation such that larger islands have more species and isolated islands have fewer species (that is, positive species-area and negative species-isolation relationships). However, experimental tests of this theory have been limited, owing to the difficulty in experimental manipulation of islands at the scales at which speciation and long-distance colonization are relevant. Here we have used the human-aided transport of exotic anole lizards among Caribbean islands as such a test at an appropriate scale. In accord with theory, as anole colonizations have increased, islands impoverished in native species have gained the most exotic species, the past influence of speciation on island biogeography has been obscured, and the species-area relationship has strengthened while the species-isolation relationship has weakened. Moreover, anole biogeography increasingly reflects anthropogenic rather than geographic processes. Unlike the island biogeography of the past that was determined by geographic area and isolation, in the Anthropocene--an epoch proposed for the present time interval--island biogeography is dominated by the economic isolation of human populations.

Testing the island effect in adaptive radiation: rates and patterns of morphological diversification in Caribbean and mainland Anolis lizards

Many of the classic examples of adaptive radiation, including Caribbean Anolis lizards, are found on islands. However, Anolis also exhibits substantial species richness and ecomorphological disparity on mainland Central and South America. We compared patterns and rates of morphological evolution to investigate whether, in fact, island Anolis are exceptionally diverse relative to their mainland counterparts. Quite the contrary, we found that rates and extent of diversification were comparable--Anolis adaptive radiation is not an island phenomenon. However, mainland and Caribbean anoles occupy different parts of morphological space; in independent colonizations of both island and mainland habitats, island anoles have evolved shorter limbs and better-developed toe pads. These patterns suggest that the two areas are on different evolutionary trajectories. The ecological causes of these differences are unknown, but may relate to differences in predation or competition among mainland and island communities.

Aplasia cutis congenita in two sibs discordant for pyloric atresia

We report two sibs who were the products of a consanguineous mating, and who had an extensive form of aplasia cutis congenita (ACC). In one of them the generalized skin disorder was manifested by slipping off of the epidermis and mucous membranes with the slightest trauma. This sib also had pyloric atresia and other congenital malformations. Two hypotheses are presented to explain the discordance between the siblings for the abnormalities other than the ACC. One hypothesis assumes varying degrees of severity of the same autosomal recessive disease. The second suggests linkage between the gene for ACC and the gene for an epidermolysis bullosa (EB)-like disorder and pyloric atresia. a recombination event involving the EB-pyloric atresia gene in one carrier parent would then lead to an offspring with only ACC. Prenatal diagnosis is suggested by monitoring alpha-fetoprotein levels in aminotic fluid.

Adaptive radiation along a deeply conserved genetic line of least resistance in Anolis lizards

On microevolutionary timescales, adaptive evolution depends upon both natural selection and the underlying genetic architecture of traits under selection, which may constrain evolutionary outcomes. Whether such genetic constraints shape phenotypic diversity over macroevolutionary timescales is more controversial, however. One key prediction is that genetic constraints should bias the early stages of species divergence along “genetic lines of least resistance” defined by the genetic (co)variance matrix, G. This bias is expected to erode over time as species means and G matrices diverge, allowing phenotypes to evolve away from the major axis of variation. We tested for evidence of this signal in West Indian Anolis lizards, an iconic example of adaptive radiation. We found that the major axis of morphological evolution was well aligned with a major axis of genetic variance shared by all species despite separation times of 20–40 million years, suggesting that divergence occurred along a conserved genetic line of least resistance. Further, this signal persisted even as G itself evolved, apparently because the largest evolutionary changes in G were themselves aligned with the line of genetic least resistance. Our results demonstrate that the signature of genetic constraint may persist over much longer timescales than previously appreciated, even in the presence of evolving genetic architecture. This pattern may have arisen either because pervasive constraints have biased the course of adaptive evolution or because the G matrix itself has been shaped by selection to conform to the adaptive landscape.

Noninvasive diagnosis of pulmonary arterial hypertension in chronic obstructive pulmonary disease: right ventricular ejection fraction at rest

Because right ventricular ejection fraction (RVEF) depends on impedance to RV ejection, the hypothesis was tested that an abnormality in radionuclide-determined RVEF would be a useful noninvasive predictor of pulmonary artery (PA) hypertension in patients with chronic obstructive pulmonary disease (COPD). Simultaneous measurements of resting RVEF and PA pressure were made in 30 patients with COPD. All were stable and without clinical evidence of respiratory decompensation or congestive heart failure. Eleven patients had normal (less than 20 mm Hg) mean PA pressure and 19 patients had PA hypertension. The average RVEF was 41 +/- 7% (range 29 to 60%). Five patients had normal (greater than 45%) and 25 patients depressed RVEF. An inverse linear relation between mean PA pressure and RVEF was present (r = -0.74). In the group with normal PA pressure, RVEF averaged 48% (range 42 to 60%). In the group with PA hypertension, RVEF averaged 36% (range 29 to 44%). RVEF was significantly higher in the group with PA hypertension. Using RVEF less than 45% as an indicator of PA hypertension, the sensitivity was 100%, the specificity 55%, and the predictive accuracy of a positive result 79%. Using RVEF less than or equal to 40% as an indicator of PA hypertension, the sensitivity was 75%, the specificity 100%, and the predictive accuracy of a positive study 100%. Thus, radionuclide-determined RVEF using the first-pass technique and a multicrystal camera is a useful noninvasive test for diagnosing PA hypertension in patients with advanced COPD.

Retromammary versus retropectoral breast augmentation-a comparative study

Repeated postaugmentation capsular formation following retromammary silicone implantation led surgeons to seek an alternative procedure. In 1968 Dempsey and Latham first reported the "subpectoral" route for location of the implant. Since then little data has been published comparing retromammary and retropectoral breast augmentation. The aim of this study is to compare the two procedures in terms of various factors affecting the physical and emotional well-being of the breast-augmented patient; breast firmness (according to Baker's classification), patient approval, the surgeon's judgment, and the husband's or partner's evaluation are all weighed. The study included 40 patients, 20 of whom underwent retromammary augmentation, the remaining 20 retropectoral augmentation. All 40 responded to a questionnaire designed to elicit comparative data. A detailed analysis of the results was made, leading to the following conclusions: first, patient approval was largely the same in the two groups, although slightly higher in the retropectoral group. However, both surgeons and husbands preferred the retropectoral method of prosthesis insertion.

Response to dopamine hydrochloride in the hepatorenal syndrome

Functional renal failure accompanying advanced cirrhosis of the liver carries a grave prognosis. Seven patients with the hepatorenal syndrome and five patients with decompensated cirrhosis of the liver without renal failure were studied by the xenon Xe 133 washout technique. Mean renal blood flow and its cortical component were decreased in both groups compared to normal transplant donors, but to a significantly greater degree in hepatorenal syndrome. In hepatorenal patients, intra-arterial infusion of subpresor doses of dopamine hydrochloride improved the angiographic appearance of the renal cortical vasculatrue and the cortical blood flow rate. Urine flow rate and glomerular filtration rate did not consistently improve with 12- to 24-hour intravenous infusions, although two patients survived, temporally related to the study. These patients had shown signs of liver function recovery.

Relative analgesic potencies of morphine and hydromorphone in postoperative pain

Because of discrepancies in the estimates of the relative analgesic potencies of hydromorphone and morphine, the drugs were compared in two four-point, double-blind bioassays. In the first study, hydromorphone, 1 and 2 mg, was compared with morphine, 5 and 10 mg, in 31 postoperative patients; in the second, hydromorphone, 0.5 and 1 mg, was compared with morphine, 5 and 10 mg, in 112 postoperative patients. Subjective responses to nurse-observer questions were used to quantitate analgesia for postoperative pain. Hydromorphone is more potent than commonly believed: approximately 0.9 to 1.2 mg is equianalgesic with 10 mg of morphine, with a similar incidence of side effects.

Effects of ouabain on myocardial oxygen supply and demand in patients with chronic coronary artery disease. A hemodynamic, volumetric, and metabolic study in patients without heart failure

The effects of digitalis glycosides on myocardial oxygen supply and demand are of particular interest in the presence of obstructive coronary artery disease, but have not been measured previously in man. We assessed the effects of ouabain (0.015 mg/kg body weight) on hemodynamic, volumetric, and metabolic parameters in 11 patients with severe chronic coronary artery disease without clinical congestive heart failure. Because the protocol was long and involved interventions which might affect the determinations, we also studied in nine patients using an identical protocol except that ouabain administration was omitted. Left ventricular end-diastolic pressure and left ventricular end-diastolic volume fell in each patient given ouabain, even though they were initially elevated in only two patients. Left ventricular end-diastolic pressure fell from 11.5+/-1.4 (mean+/-SE) to 5.6+/-0.9 mm Hg (P less than 0.001) and left ventricular end-diastolic volume fell from 100+/-17 to 82+/-12 ml/m2 (P less than 0.01) 1 h after ouabain infusion was completed. The maximum velocity of contractile element shortening increased from 1.68+/-0.11 ml/s to 2.18+/-0.21 muscle-lengths/s (P less than 0.05) and is consistent with an increase in contractility. No significant change in these parameters occurred in the control patients. No significant change in myocardial oxygen consumption occurred after ouabain administration but this may be related to a greater decrease in mean arterial pressure in the ouabain patients than in the control patients. We conclude that in patients with chronic coronary artery disease who are not in clinical congestive heart failure left ventricular end-diastolic volume falls after ouabain administration even when it is initially normal. Though this fall would be associated with a decrease in wall tension, and, therefore, of myocardial oxygen consumption, it may not be of sufficient magnitude to prevent a net increase in myocardial oxygen consumption. Nevertheless, compensatory mechanisms prevent a deterioration of resting myocardial metabolism.

Contrasting acute effects of vasodilators (nitroglycerin, nitroprusside, and hydralazine) on right ventricular performance in patients with chronic obstructive pulmonary disease and pulmonary hypertension: a combined radionuclide-hemodynamic study

Fourteen patients with chronic obstructive pulmonary disease, mild to moderate pulmonary hypertension, and diminished right ventricular (RV) ejection fraction were studied acutely with use of a combined radionuclide-hemodynamic approach to assess and contrast the effects of 3 vasodilators on RV performance and central hemodynamic function. Nitroglycerin significantly decreased mean right atrial pressure, RV end-diastolic volume index, mean pulmonary artery pressure, cardiac index, and arterial oxygen tension, but did not affect pulmonary vascular resistance index and increased RV ejection fraction. Nitroprusside had similar effects on mean right atrial pressure, RV end-diastolic volume index, mean pulmonary artery pressure, cardiac index, and arterial oxygen tension, but also mildly decreased pulmonary vascular resistance index and did not alter RV ejection fraction. In contrast, hydralazine decreased pulmonary vascular resistance index and increased cardiac index and RV ejection fraction. The increase in ejection fraction correlated well with the decrease in pulmonary vascular resistance. These data suggest that in patients with mild to moderate secondary pulmonary hypertension, acute administration of hydralazine results in a substantial improvement in RV performance by virtue of decreasing pulmonary vascular resistance. In contrast, nitroglycerin and nitroprusside demonstrate predominant effects that reduce preload, cardiac index, and arterial oxygen tension. Based on these data, afterload reduction with vasodilators such as hydralazine may be potentially useful in selected patients with pulmonary disease and secondary pulmonary hypertension and appear preferable to agents that primarily reduce preload. Further long-term studies are necessary to establish therapeutic efficacy.

A critical appraisal of the use of microRNA data in phylogenetics

Recent progress in resolving the tree of life continues to expose relationships that resist resolution, which drives the search for novel sources of information to solve these difficult phylogenetic problems. A recent example, the presence and absence of microRNA families, has been vigorously promoted as an ideal source of phylogenetic data and has been applied to several perennial phylogenetic problems. The utility of such data for phylogenetic inference hinges critically both on developing stochastic models that provide a reasonable description of the process that give rise to these data, and also on the careful validation of those models in real inference scenarios. Remarkably, however, the statistical behavior and phylogenetic utility of microRNA data have not yet been rigorously characterized. Here we explore the behavior and performance of microRNA presence/absence data under a variety of evolutionary models and reexamine datasets from several previous studies. We find that highly heterogeneous rates of microRNA gain and loss, pervasive secondary loss, and sampling error collectively render microRNA-based inference of phylogeny difficult. Moreover, our reanalyses fundamentally alter the conclusions for four of the five studies that we reexamined. Our results indicate that the capacity of miRNA data to resolve the tree of life has been overstated, and we urge caution in their application and interpretation.

Amber fossils demonstrate deep-time stability of Caribbean lizard communities

Whether the structure of ecological communities can exhibit stability over macroevolutionary timescales has long been debated. The similarity of independently evolved Anolis lizard communities on environmentally similar Greater Antillean islands supports the notion that community evolution is deterministic. However, a dearth of Caribbean Anolis fossils--only three have been described to date--has precluded direct investigation of the stability of anole communities through time. Here we report on an additional 17 fossil anoles in Dominican amber dating to 15-20 My before the present. Using data collected primarily by X-ray microcomputed tomography (X-ray micro-CT), we demonstrate that the main elements of Hispaniolan anole ecomorphological diversity were in place in the Miocene. Phylogenetic analysis yields results consistent with the hypothesis that the ecomorphs that evolved in the Miocene are members of the same ecomorph clades extant today. The primary axes of ecomorphological diversity in the Hispaniolan anole fauna appear to have changed little between the Miocene and the present, providing evidence for the stability of ecological communities over macroevolutionary timescales.

Thermal niche evolution across replicated Anolis lizard adaptive radiations

Elucidating how ecological and evolutionary mechanisms interact to produce and maintain biodiversity is a fundamental problem in evolutionary ecology. Here, we focus on how physiological evolution affects performance and species coexistence along the thermal niche axis in replicated radiations of Anolis lizards best known for resource partitioning based on morphological divergence. We find repeated divergence in thermal physiology within these radiations, and that this divergence significantly affects performance within natural thermal environments. Morphologically similar species that co-occur invariably differ in their thermal physiology, providing evidence that physiological divergence facilitates species coexistence within anole communities. Despite repeated divergence, phylogenetic comparative analyses indicate that physiological traits have evolved more slowly than key morphological traits related to the structural niche. Phylogenetic analyses also reveal that physiological divergence is correlated with divergence in broad-scale habitat climatic features commonly used to estimate thermal niche evolution, but that the latter incompletely predicts variation in the former. We provide comprehensive evidence for repeated adaptive evolution of physiological divergence within Anolis adaptive radiations, including the complementary roles of physiological and morphological divergence in promoting community-level diversity. We recommend greater integration of performance-based traits into analyses of climatic niche evolution, as they facilitate a more complete understanding of the phenotypic and ecological consequences of climatic divergence.