Fat extrusion and septal reset in patients with the tear trough triad: a critical appraisal

Arcus marginalis release, fat extrusion, and septal reset were applied to 71 selected patients with a constellation of orbital deformities the authors term a "tear trough triad." Of the initial 71 patients, 59 had complete follow-up records. Evaluated by means of a proportional topographic scale, 95 percent of patients achieved significant improvement. Equally important, no incidence of middle lamella contracture occurred in the entire series. The authors conclude that the procedure is safe and effective in selected patients.     

Naturopathy: a critical appraisal

"Naturopathic medicine" is a recent manifestation of the field of naturopathy, a 19th-century health movement espousing "the healing power of nature." "Naturopathic physicians" now claim to be primary care physicians proficient in the practice of both "conventional" and "natural" medicine. Their training, however, amounts to a small fraction of that of medical doctors who practice primary care. An examination of their literature, moreover, reveals that it is replete with pseudoscientific, ineffective, unethical, and potentially dangerous practices. Despite this, naturopaths have achieved legal and political recognition, including licensure in 13 states and appointments to the US Medicare Coverage Advisory Committee. This dichotomy can be explained in part by erroneous representations of naturopathy offered by academic medical centers and popular medical Web sites.     

Taxonomy and fossils: a critical appraisal

Many compendia at the species, genus and family levels document the fossil record, but these are not standardized, nor usually critical in content, and few are available on the World Wide Web. The sampling of the available record is good for organisms with fossilizable parts, but preservational constraints on the entire morphology, life history and geographical distribution lead to difficulties in recognizing and naming species. We recommend abandoning some of the palaeontological species concepts such as chronospecies and stratospecies, and we advocate species recognition based on unique combinations of characters. The compilation of species lists is extremely time consuming, and given the inherent problems we suggest that compilation of generic lists is a more achievable goal because genera are recognized by definitive morphological characters. In calculating taxon duration, care must be taken to distinguish between mono-, para- and polyphyletic groups, the first being the only reliable unit for use in calculating diversity curves. We support the inclusion of fossils into classifications based on Recent organisms, but we recognize some of the problems this may pose for standard Linnaean classifications. Web-based taxonomy is the way forward, having the advantages of speed and currency of information dissemination, universal access with links to primary literature and increasingly sophisticated imagery. These advantages over conventional outlets will only be realized with careful Web design and a commitment to maintenance.     

Effectiveness of instruction in critical appraisal (evidence-based medicine) skills: a critical appraisal

OBJECTIVE: To examine the evidence that the teaching of critical appraisal (evidence-based medicine) skills to undergraduate medical students or residents will result in significant gains in knowledge and increased use of the literature in clinical decision-making. DATA SOURCES: Articles published from 1966 to 1995, retrieved through a MEDLINE search supplemented by manual searches; review of bibliographies maintained by individuals involved in teaching critical appraisal skills; and a previous methodological review. STUDY SELECTION: Articles were selected if the study involved some form of control group, although strict randomization was not required, and a measure of performance followed the intervention. Articles were excluded if they simply reported the process of teaching critical appraisal skills or used some form of "happiness index." DATA SYNTHESIS: There were 10 studies of the impact of teaching critical appraisal skills, 6 involving medical students and 4 involving residents. Results from 3 of the studies were nearly uninterpretable and thus were excluded; the remaining 7 were methodologically acceptable. Analysis showed that interventions implemented in undergraduate programs resulted in significant gains in knowledge, as assessed by a written test (mean gain 17.0%; standard deviation [SD] 4.0%). Conversely, studies at the residency level consistently showed a small change in knowledge (mean gain 1.3%; SD 1.7%). Two studies that examined residents'' use of the literature were unable to demonstrate any positive changes. CONCLUSIONS: Studies of the effect of teaching critical appraisal skills on gains in knowledge at the undergraduate level showed consistent improvement. By contrast, changes in knowledge at the residency level were small. Several suggestions from the educational literature are offered to increase effectiveness of critical appraisal interventions.     

Comparative biochemistry and physiology in Brazil: a critical appraisal

Brazil stood out as the country with the highest number of submissions to the editorial project dedicated to Latin America by the journal Comparative Biochemistry and Physiology. Therefore, we felt that it was important to critically discuss the state of comparative biochemistry and physiology in this country. Our study is based on data collected from the ISI Web-of-Science. We analyzed publication trends through time, availability of novel approaches and techniques, patterns of collaboration among different geographical regions, patterns of collaboration with researchers abroad, and relative efforts dedicated to the study of biochemical and physiological adaptation of native fauna representing different terrestrial Brazilian biomes. Overall, our data shows that comparative biochemistry and physiology is a lively and productive discipline, but that some biases limit the scope of the field in Brazil. Some important limitations are the very heterogeneous distribution of research nuclei throughout the country and the absence of some important approaches, such as remote sensing and the use of molecular biology techniques in a comparative or evolutionary context. We also noticed that international collaboration far surpasses interregional collaboration, and discuss the possible causes and consequences of this situation. Finally, we found that Brazilian comparative biochemistry and physiology is biome-biased, as the Amazonian fauna has received far more attention than the whole pool of fauna representing other terrestrial biomes. We discuss the possible causes of these biases, and propose some directions that may contribute to invigorate the field in the country.     

Microbial biosynthesis and applications of gentamicin: a critical appraisal

Gentamicin is an aminoglycoside antibiotic produced by various species of the genus Micromonospora and has received much attention in the recent years as a broad-spectrum antibiotic for treatment of various infections. It exists as a complex of closely related aminoglycoside structures and the clinically significant one is the gentamicin C complex. This review article focuses attention on the present status of knowledge and the main advancements achieved in the last few decades on the subject of gentamicin with regard to its production, biosynthetic pathway, mode of action, and uses. The various nutritional and environmental parameters affecting gentamicin production and the factors affecting the release of bound gentamicin are discussed. Further, strain improvement using UV and/or chemical mutagenesis can be applied to augment the efficiency of the producer strain and a number of case studies are presented. Different detection and quantitative methods for gentamicin estimation and the mode of action of gentamicin are discussed in detail. This antibiotic finds extensive use in combination chemotherapy and as a drug for different delivery agents for treatment of osteomyelitis and other recent applications in gene therapy.     

Sixty consecutive breast reconstructions with the inflatable expander: a critical appraisal

Breast reconstruction using inflatable expanders has become an established and preferred technique. Although our knowledge of the biomechanical changes occurring in expanded skin has increased greatly, little information is available regarding average aesthetic results achieved with this technique. In order to eliminate the bias of best case selection reports, this study of 60 consecutive patients undergoing skin-expansion breast reconstruction was undertaken. Results of the study demonstrated a significant frequency and diversity of complications. In particular, immediate breast reconstruction with skin expanders was identified as a high-risk procedure because of its association with skin necrosis and delayed wound healing. Although two procedures--insertion and replacement--had been anticipated, patients from both the Boston and New York groups required approximately three operations to complete the expansion process. Average aesthetic results, often characterized by problems of symmetry, ptosis, and contour, need to be recognized and improved.     

Studies on leukocyte beta-adrenergic receptors in depression: a critical appraisal

Alterations in beta-adrenergic receptors (BAR) of human mononuclear leukocytes (MNL) are considered to reflect changes in central noradrenergic function and have been studied in a number of diseases. This paper critically reviews the results of recent studies on MNL-BAR in depression, with particular emphasis on the biochemical and clinical methodologies used. Despite considerable differences in these methods, a number of laboratories report consistent decreases in MNL-BAR density and significantly reduced functional response in patients as compared to controls. These studies used MNL, isolated from patients who had a greater than 14 day drug washout, and BAR-densities were measured in membrane preparations, using full Scatchard analyses, and 125I-ICYP or 3H-DHA as the ligand. Functional response of MNL-BARs was assessed by the determination of isoproterenol-stimulated cyclic AMP accumulation. A comparison of methods used by these groups further indicates that additional biochemical parameters such as lymphocyte preparation and standardized experimental conditions for the binding assays are also important for obtaining consistent results. The clinical methods in rigorous study designs also include clearly stated inclusion/exclusion criteria for patients, and age-, and gender-matched patient-control populations. Whether the reduced MNL-BAR density and function is an inherited abnormality in depressed patients, or results from downregulation by elevated catecholamines is at present not known. Studies are needed to characterize further the changes in MNL-BARs in depression and to evaluate the effects of caetcholamines and hormones on this system. Based on critical assessment of the methods reviewed we propose specific biochemical and clinical guidelines, and recommend, that these be followed in future studies on MNL-BARs in this disease.     

The presence of actin in nuclei: a critical appraisal.

To assess the significance of actin associations with nuclei, we have examined Amoeba proteus nuclei for the presence of labeled actin under a variety of circumstances without (in most instances) isolating nuclei or breaking up cytoplasms prior to the extraction of proteins.We first established that: the 42,000 dalton proteins (presumed to be actin) present in cytoplasm and non-isolated nuclei are identical electrophoretically; the putative actin of amebas has the same size and almost the same isoelectric point as rat muscle actin; and the peptide “fingerprints” of putative ameba actin and rat actin are very similar after tryptic digestion. We therefore concluded that the 42,000 dalton protein of ameba is actin.We determined that: the concentrations of actin in the cytoplasm and nucleus of amebas are the same; actin is readily lost from nuclei that are released from lysed cells; shortly after a ³⁵S-labeled nucleus is transplanted into unlabeled cytoplasm, or an unlabeled nucleus is transplanted into ³⁵S-labeled cytoplasm, the concentration of ³⁵S-actin in nucleus and cytoplasm is the same; and when cells containing ³⁵S-actin are subjected to long chase periods on unlabeled food, the concentrations of ³⁵S-actin in nucleus and cytoplasm fall in parallel. These observations taken together suggest that actin is not tightly associated with nuclei. Rather, actin may associate with nuclei for the trivial reason that the nuclear envelope is no barrier to free movement of that protein between the two compartments.We conclude that the mere presence of actin in nuclei is insufficient grounds for assuming that it has any role in nuclear functions, such as, for example, chromosome condensation.     

The role of the septal reset in creating a youthful eyelid-cheek complex in facial rejuvenation

Resetting of the septum orbitale over the orbital rim, or "septal reset," is the latest step in achieving periorbital rejuvenation in composite rhytidectomy. The first significant step was the addition of orbicularis repositioning to conventional lateral vector deep plane rhytidectomy, followed by orbital fat preservation using the arcus marginalis release and fat transposition over the orbital rim. Those early procedures have been further refined to include the zygomaticus muscles with the orbicularis oculi in the composite flap, or zygorbicular cheek flap, and a septal reset. The septum orbitale reset has distinct advantages over transposition of orbital fat alone, as it creates a firmer undersurface for the lower eyelid. This maneuver will create a truly youthful lower eyelid-cheek complex, as the normal concave aging skeletonization of the periorbit is transformed to a convex contour of youth. The effectiveness of this operation can be demonstrated in most variations of human anatomy, whether congenital or iatrogenic, allowing the plastic surgeon to utilize the septal reset in virtually every patient undergoing and desiring a harmonious facial rejuvenation.     

Using marine macroalgae for carbon sequestration: a critical appraisal

There has been a good deal of interest in the potential of marine vegetation as a sink for anthropogenic C emissions (“Blue Carbon”). Marine primary producers contribute at least 50% of the world’s carbon fixation and may account for as much as 71% of all carbon storage. In this paper, we analyse the current rate of harvesting of both commercially grown and wild-grown macroalgae, as well as their capacity for photosynthetically driven CO₂ assimilation and growth. We suggest that CO₂ acquisition by marine macroalgae can represent a considerable sink for anthropogenic CO₂ emissions and that harvesting and appropriate use of macroalgal primary production could play a significant role in C sequestration and amelioration of greenhouse gas emissions.     

Elemental and molecular detection for Quantum Dots-based immunoassays: a critical appraisal

A critical comparison between Elemental Mass Spectrometry (ICP-MS) and molecular fluorescence, as detection techniques for CdSe/ZnS Quantum Dots (QDs)-based immunoassays is presented here. Using a QDs-based progesterone immunoassay as "model" analytical system the features of both detection modes has been investigated. Minimal changes, compared to the previously developed fluorescent approach, were necessary to build the corresponding inhibition curve for the progesterone immunoassay using ICP-MS detection of cadmium (contained in the QDs core). Adequate agreement between results obtained using both elemental and molecular techniques for the determination of progesterone in cow milk has been obtained. Moreover, results from the comparison showed that fluorescence detection of the QDs is simpler, less time consuming and less expensive, but ICP-MS detection affords alternative and useful information unattainable using luminescence detection. First of all, ICP-MS allowed mass balances to be carried out (all along the sample preparation) providing an internal validation of the immunoassay procedure. Secondly, matrix-independent quantification as provided by ICP-MS enabled a direct determination of progesterone in raw milk without any further sample preparation (dilution) step. As a matter of fact, ICP-MS results showed that the quenching matrix effect suffered on bioconjugated QDs fluorescence emission (e.g. when the immunoassay was carried out directly in whole milk without any dilution) could be unequivocally attributed to nonspecific interactions between the matrix of the whole milk and the QDs surface. Finally, better sensitivity could be obtained with ICP-MS detection, IC(10)=0.028 ng/mL, versus 0.11 ng/mL using conventional fluorimetric detection, just by using lower reagents concentrations.     

Hormone action in plant development: A critical appraisal

Book Review

Hormone action in plant development: A critical appraisalG.V. Hoad, J.R. Lenton, M.B. Jackson and R.K. Atkin (Eds.), London: Butterworths, 1987. 315 pages. £21.00. ISBN 0408 007966     

Nasal cavity carcinogenesis by N-nitrosamines: a critical appraisal

This review is a critical appraisal of our current knowledge on nasal cavity carcinogenesis by nitrosamines. The pathology and pathogenesis of nitrosamine-induced tumors in the nasal cavity of rodents is summarized while controversies on the underlying molecular mechanisms are discussed in more detail. Investigations on the distribution of metabolically competent cell types, the cellular site(s) of nitrosamine metabolism, as well as reports on the cellular distribution and persistence of DNA-adducts strongly suggest that DNA-adducts formed from reactive metabolites are not immediately responsible for the genesis of nasal cavity tumors. A preexisting high proliferative ability has also been suggested as a factor rendering certain cell types more susceptible to the carcinogenic actions of nitrosamines in the nasal cavity. However, this hypothesis has been clearly rejected by more recent investigations. Recent studies have shown that nitrosamines can stimulate the secretion of growth factors via interaction with neurotransmitter receptors in the lungs and that this molecular mechanism is an important factor in determining the histological phenotype of the developing lung tumors. In light of the fact that secretory cells are the main sites of DNA-adduct accumulation and toxic lesions in the nasal cavities of nitrosamine treated rodents, it is suggested that similar mechanisms may mediate the genesis of nitrosamine-induced nasal cavity tumors.     

p57(Kip2) and cancer: time for a critical appraisal

p57(Kip2) is a cyclin-dependent kinase inhibitor belonging to the Cip/Kip family, which also includes p21(Cip1) and p27(Kip1). So far, p57(Kip2) is the least-studied Cip/Kip protein, and for a long time its relevance has been related mainly to its unique role in embryogenesis. Moreover, genetic and molecular studies on animal models and patients with Beckwith-Wiedemann syndrome have shown that alterations in CDKN1C (the p57(Kip2) encoding gene) have functional relevance in the pathogenesis of this disease. Recently, a number of investigations have identified and characterized heretofore unexpected roles for p57(Kip2). The protein appears to be critically involved in initial steps of cell and tissue differentiation, and particularly in neuronal development and erythropoiesis. Intriguingly, p27(Kip1), the Cip/Kip member that is most homologous to p57(Kip2), is primarily involved in the process of cell cycle exit. p57(Kip2) also plays a critical role in controlling cytoskeletal organization and cell migration through its interaction with LIMK-1. Furthermore, p57(Kip2) appears to modulate genome expression. Finally, accumulating evidence indicates that p57(Kip2) protein is frequently downregulated in different types of human epithelial and nonepithelial cancers as a consequence of genetic and epigenetic events. In summary, the emerging picture is that several aspects of p57(Kip2)'s functions are only poorly clarified. This review represents an appraisal of the data available on the p57(Kip2) gene and protein structure, and its role in human physiology and pathology. We particularly focus our attention on p57(Kip2) changes in cancers and pharmacological approaches for modulating p57(Kip2) levels.     

Begomovirus research in India: A critical appraisal and the way ahead

Begomoviruses are a large group of whitefly-transmitted plant viruses containing single-stranded circular DNA encapsidated in geminate particles. They are responsible for significant yield losses in a wide variety of crops in India. Research on begomoviruses has focussed on the molecular characterization of the viruses, their phylogenetic analyses, infectivities on host plants, DNA replication, transgenic resistance, promoter analysis and development of virus-based gene silencing vectors. There have been a number of reports of satellite molecules associated with begomoviruses. This article aims to summarize the major developments in begomoviral research in India in the last approximately 15 years and identifies future areas that need more attention.