Recurrent mammary hyperplasia: current concepts

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the factors leading to undesirable long-term reduction mammaplasty results. 2. Delineate the differential diagnosis of recurrent hypermastia. 3. Understand the significance of preoperative counseling, particularly with regard to expected postoperative outcome. 4. Understand short-term and long-term expected and undesirable postoperative results. 5. Understand safe and effective surgical planning for revision reduction mammaplasty. A large majority of patients who undergo reduction mammaplasty are satisfied with their aesthetic outcome and resolution of preoperative symptoms. Occasionally, patients present with postoperative concerns; these are usually aesthetic in nature and caused by breast scarring, breast asymmetry, and/or breast shape. Inadequate excision and recurrent hypermastia are more complex concerns, which require careful evaluation and treatment. Analysis of both the presenting deformity and the original surgical approach is critical in determining an operative plan. This article discusses the safe approach to revision reduction mammaplasty. Current concepts are discussed and presented. An algorithm for decision-making is presented and discussed.     

Polyglandular autoimmune syndrome: current concepts.

The polyglandular autoimmune syndrome (PGAS) is characterized by the association of two or more endocrine disorders that are mediated by autoimmune mechanisms and usually lead to a hypofunctional state. In this review we classify the various types of PGAS and discuss their clinical features and the pathophysiologic autoimmune mechanisms that are thought to play an important role. Circulating organ- and cell-specific autoantibodies are frequently detected in patients with the syndrome and may be a marker of future organ failure. PGAS should be considered in patients with one or more of the disorders constituting the syndrome; this should facilitate early diagnosis and perhaps even prevention of other components of the disease. Early recognition and replacement therapy can be life-saving, particularly when there is adrenal or thyroid insufficiency.     

Vaginitis: current microbiologic and clinical concepts.

Infectious vaginitis occurs when the normal vaginal flora is disrupted; it may arise when saprophytes overwhelm the host immune response, when pathogenic organisms are introduced into the vagina or when changes in substrate allow an imbalance of microorganisms to develop. Examples of these types of vaginitis include the presence of chronic fungal infection in women with an inadequate cellular immune response to the yeast, the introduction of trichomonads into vaginal epithelium that has a sufficient supply of glycogen, and the alteration in bacterial flora, normally dominated by Lactobacillus spp., and its metabolites that is characteristic of "nonspecific vaginitis". The authors review microbiologic and clinical aspects of the fungal, protozoal and bacterial infections, including the interactions of bacteria thought to produce nonspecific vaginitis, that are now recognized as causing vaginitis. Other causes of vaginitis are also discussed.     

Cellulose biosynthesis: current views and evolving concepts

* AIMS: To outline the current state of knowledge and discuss the evolution of various viewpoints put forth to explain the mechanism of cellulose biosynthesis. * SCOPE: Understanding the mechanism of cellulose biosynthesis is one of the major challenges in plant biology. The simplicity in the chemical structure of cellulose belies the complexities that are associated with the synthesis and assembly of this polysaccharide. Assembly of cellulose microfibrils in most organisms is visualized as a multi-step process involving a number of proteins with the key protein being the cellulose synthase catalytic sub-unit. Although genes encoding this protein have been identified in almost all cellulose synthesizing organisms, it has been a challenge in general, and more specifically in vascular plants, to demonstrate cellulose synthase activity in vitro. The assembly of glucan chains into cellulose microfibrils of specific dimensions, viewed as a spontaneous process, necessitates the assembly of synthesizing sites unique to most groups of organisms. The steps of polymerization (requiring the specific arrangement and activity of the cellulose synthase catalytic sub-units) and crystallization (directed self-assembly of glucan chains) are certainly interlinked in the formation of cellulose microfibrils. Mutants affected in cellulose biosynthesis have been identified in vascular plants. Studies on these mutants and herbicide-treated plants suggest an interesting link between the steps of polymerization and crystallization during cellulose biosynthesis. * CONCLUSIONS: With the identification of a large number of genes encoding cellulose synthases and cellulose synthase-like proteins in vascular plants and the supposed role of a number of other proteins in cellulose biosynthesis, a complete understanding of this process will necessitate a wider variety of research tools and approaches than was thought to be required a few years back.     

Mutagens as carcinogens: development of current concepts

The earliest work on reactions of mutagenic carcinogens with DNA, in which the author participated, is recalled in a personal reminiscence. Some significant consequences of this approach for studies of the mode of action of mutagenic carcinogens are briefly discussed, with regard to the types of mutation induced, and to current concepts of the involvement of somatic mutation in experimental cancer and in the aetiology of human cancer.     

Tick-host interaction: a synthesis of current concepts

Ixodid ticks are recognized world-wide as major vectors of arboviruses, rickettsiae, spirochaetes and parasitic protozoa of man and domestic animals. Some ticks also inject a debilitating, sometimes fatal, paralytic toxin in their saliva. All these factors are transmitted via the salivary glands and mouthparts of the feeding tick. Tick feeding is a prolonged and complex process. Major developmental events occurring within the tick during feeding, as well as extensive tick-host interactions, all influence the likelihood of pathogen transmission. In this review, Reuben Kaufman discusses the sequence and complexity of these interactions.     

EMF and current cancer concepts

Exposure to power frequency electric and magnetic fields (EMF) is ubiquitous, and a body of epidemiologic studies has produced evidence suggestive of a possible link between EMF exposure and cancer of several types. This paper provides a perspective that holds key findings in the EMF literature against the background of important models and established principles in cancer biology. It is intended primarily for scientists whose expertise lies outside of cancer biology and animal bioassays. Current thinking holds that carcinogenesis is a multistep process that requires at least two genotoxic events in its critical path but that is facilitated by nongenotoxic proliferative effects on target cells. EMF, which itself is not believed to be genotoxic, could influence carcinogenesis if it exerted either direct or indirect effects on target cell turnover. Such effects could operate through receptor-mediated or nonreceptor-mediated pathways. However, effects relevant to carcinogenesis have not been confirmed, and a mode of action for EMF has not been determined. Chronic bioassays in rodents are in progress to examine the potential carcinogenicity of EMFs. EMF research has the opportunity to capitalize on the recent major advances in our understanding of carcinogenic processes. © 1996 Wiley-Liss, Inc.     

Digitalis use in acute myocardial infarction: current concepts

Digitalis is one of the oldest and most commonly prescribed medications. There has been continuing controversy regarding its use in acute myocardial infarction. Recent information from animal experiments and clinical investigation serves as a guide for its appropriate use in this situation. When it is used appropriately and judiciously there is no increase in toxicity or cardiac arrhythmias. In fact, there is benefit to the patient who has a failing myocardium associated with acute myocardial infarction.     

Ecology of glacier-fed rivers: current status and concepts

1. This paper is an introduction to a special issue of Freshwater Biology containing papers dealing with various aspects of the ecology of glacier-fed rivers.
2. Using similar field protocols, a wide range of glacier-fed systems were studied across Europe from the French Pyrenees to Svalbard within the framework of the European Commission project, Arctic and Alpine Stream Ecosystem Research (AASER). Recent investigations from other parts of Europe together with New Zealand and Greenland are also reported. This work has advanced our knowledge of the functioning of these types of rivers and has led to the modification and quantification of the conceptual model of Milner & Petts (1994) .
3. Glacier-fed rivers, by virtue of the dominance of physical variables in shaping macroinvertebrate communities, are not only good indicators of climate change, but also may be suitable testing grounds for examining ecological concepts.     

Airway inflammation and remodeling in asthma: current concepts

Asthma is a chronic inflammatory disorder of the airways interacting with altered structure and function of the formed elements including smooth muscle. While atopy and polarization of the airway T-cell response toward a Th-2 phenotype are important factors in asthma pathogenesis, there is increasing realization that remodeling events are also important. Evidence is presented that inflammation and altered airway structure in asthma interact through the epithelium and underlying mesenchyme. As in other chronic inflammatory disorders, a dynamic interplay between mediators, cytokines, and growth factors provides a broader base on which to identify novel preventative and therapeutic strategies in asthma.     

Catecholaminergic regulation of ovarian function in mammals: current concepts

A review of the rapidly accumulating data in the literature continues to support the notion that catecholamines regulate ovarian function, and extends the complexity of catecholaminergic effects on the ovary via interactions with pituitary and adrenal hormones. It is clear that catecholamines affect growth and differentiation of ovarian follicles, but their role in follicular rupture during ovulation and in corpus luteum function remains unclear. The effects of catecholamines (mediated by membrane receptors) on ovarian function probably should be considered paracrine but classic endocrine regulation of ovarian function cannot be ruled out. Myogenic tonus of ovarian vasculature appears to be regulated by catecholamines, and estrogens may enhance adrenergic receptors in ovarian smooth muscle cells.     

Cellular fatty acid-binding proteins: current concepts and future directions

Summary At least three different proteins are implicated in the cellular transport of fatty acid moieties: a plasmalemmal membrane and a cytoplasmic fatty acid-binding protein (FABP_PM and FABP_C, respectively) and cytoplasmic acyl-CoA binding protein (ACBP). Their putative main physiological significance is the assurance that long-chain fatty acids and derivatives, either in transit through membranes or present in intracellular compartments, are largely complexed to proteins. FABP_C distinguishes from the other proteins in that distinct types of FABP_C are found in remarkable abundance in the cytoplasmic compartment of a variety of tissues. Although their mechanism of action is not yet fully elucidated, current knowledge suggests that the function of this set of proteins reaches beyond simply aiding cytoplasmic solubilization of hydrophobic ligands, but that they can be assigned several regulatory roles in cellular lipid homeostasis.     

Embolic protection: limitations of current technology and novel concepts

Distal embolic event is one of the major limitations of coronary and non-coronary vascular interventions. Balloon and filter-based Embolic Protection Devices (EPDs) are a new class of interventional devices, used to prevent consequential morbidity and mortality of the distal embolic events. Data from first generation EPD supply proof of concept and show approximately 40% reduction in mortality and morbidity, when EPDs are used during saphenous vein grafts (SVGs) interventions. Current limitations of all first generation EPD technology taper their penetration. With breakthroughs in embolic protection technology, it is estimated that, in the near future, EPDs will be used with stenting in all high-risk lesions (SVGs, carotid arteries and acute coronary syndromes), become the standard of care and even be used in low risk cases.