Management of secondary Paget's disease of the vulva associated with transitional cell carcinoma.

PURPOSE: Secondary extramammary Paget's disease (EMPD) related to urothelial carcinoma is rare, with some cases presenting synchronously with either a primary neoplasm or recurrence of a neoplasm and other cases presenting up to 13 years prior to the detection of urothelial carcinoma. In this report, we will review the presentation, diagnosis, pathophysiology, management, and literature review of cases of secondary EPMD associated with urothelial carcinoma. METHODS: We reviewed the English literature for all cases of secondary EMPD presenting synchronously with or in patients with a history of urothelial carcinoma, as well as treatment data for secondary vulvar Paget's. RESULTS: We identified 16 case reports and case series with a total of 20 cases of vulvar EMPD associated with urothelial carcinoma. Twelve cases presented asynchronously and 8 had EMPD preceding the diagnosis of the underlying neoplasm. There is a paucity in the literature regarding management and surgical resection is a common treatment strategy; however, nonsurgical interventions may also be effective. CONCLUSION: There is a paucity in the literature regarding management of secondary EPMD of urothelial origin, but consideration of radiation and systemic chemotherapy may be a reasonable treatment approach.

Structural information from orientationally selective DEER spectroscopy.

Double electron-electron resonance (DEER) spectroscopy can determine, from measurement of the dipolar interaction, the distance and orientation between two paramagnetic centres in systems lacking long-range order such as powders or frozen solution samples. In spin systems with considerable anisotropy, the microwave pulses excite only a fraction of the electron paramagnetic resonance (EPR) spectrum and the resulting orientation selection needs to be explicitly taken into account if a meaningful distance and orientation is to be determined. Here, a general method is presented to analyze the dipolar interaction between two paramagnetic spin centres from a series of DEER traces recorded so that different orientations of the spin-spin vector are sampled. Delocalised spin density distributions and spin projection factors (as for example in iron-sulfur clusters), are explicitly included. Application of the analysis to a spin-labelled flavoprotein reductase/reduced iron-sulfur ferredoxin protein complex and a bi-radical with two Cu(ii) ions provides distance and orientation information between the radical centres. In the protein complex this enables the protein-protein binding geometry to be defined. Experimentally, orientationally selective DEER measurements are possible on paramagnetic systems where the resonator bandwidth allows the frequencies of pump and detection pulses to be separated sufficiently to excite enough orientations to define adequately the spin-spin vector.

Histological findings of the internal inguinal ring in patients having indirect inguinal hernia.

BACKGROUND: Aiming to deepen the understanding of the factors involved in the genesis of groin hernia, this study is focused on identifying the histological changes within the muscle fibers of the internal inguinal ring in patients having indirect inguinal hernia. METHODS: In eight patients with primary or recurrent bilateral indirect inguinal hernia who underwent a Stoppa open posterior inguinal hernia repair, a tissue specimen from the edge of the internal inguinal ring was biopsied and histologically examined. RESULTS: In all of the tissue samples, remarkable degenerative changes such as fibrohyaline degeneration of the muscle fibers, vascular congestion, and phlogistic infiltration through lymphohistiocytary elements was constantly detected. Also, in the patients with recurrent hernia, the key characteristic of the muscular change was that of fibrohyaline and, occasionally, myxoid degeneration of the myocytes. Nerve endings were frequently detected within the muscular structures of the internal inguinal ring. CONCLUSION: The degenerative fibrohyaline alteration, as well as the evidence of phlogistic elements within the examined structures, could represent a reason for a contractile incompetence of the internal inguinal ring. Consequently, the described findings lead the authors to depict this inflammatory degenerative structural weakness of the internal inguinal ring as a possible culprit of indirect inguinal hernia formation.

Sphincter-like motion following mechanical dilation of the internal inguinal ring during indirect inguinal hernia procedure.

INTRODUCTION: Even today, there is still great speculation as to the underlying pathogenesis of inguinal hernia. As a result, it could be extrapolated that the vast majority of repairs are based upon conjecture. Most current repairs are founded upon the principle of "closing the defect" in the anatomy, either by suturing closed under tension, covering with a mesh or obliterating the defect with a plug. Many variants of each method are refined to achieve better clinical outcomes. Yet few, if any, strive to understand a fundamental question: "What has gone wrong with the normal physiological and anatomical mechanisms that prevent abdominal structures protruding through the abdominal wall?" We consider, in the normal subject, the muscular structures that converge and wrap around the inguinal canal as a highly dynamic structure, which forms a reactive barrier to the augmentation of intra-abdominal pressures. In effect, the structures work together like a "striated sphincter complex." Through years of surgical experience, we have seen the formation of adhesions and fibrosis in these delicate and key structures, and hypothesised that they may impair its shuttering action, thus, creating a patency of this jammed inguinal ring leading to hernia. Based upon these observations, we have created a hernia repair variant that tries to "unblock" the muscles prior to repair, thus, hopefully restoring a degree of physiologic function. METHODS: A retrospective study describes the results of 47 patients operated for indirect inguinal hernia with a standardised procedure consisting of meticulous adhesiolysis of the hernia area and mechanical dilation (divulsion) of the inguinal orifice in order to break stiff fibres within the muscle, allowing viable muscle fibres to contract freely once more. After dilation, a proprietary lamellar-shaped implant was delivered into the canal. Its form and function are designed to eliminate impingement of the cord structures and give a gentle outwards force to induce a reactive contraction of the sphincter-like muscle complex during healing. This gentle contraction offers the possibility to eliminate fixation of the implant. RESULTS: The removal of scar tissue, dilation and the introduction of the implant into the internal inguinal ring induced a forceful "gripping" contraction by the sphincter complex in all patients. Even without fixation, it became almost impossible to pull the implant out of the canal. After obliterating the orifice with the lamellar implant, it was clear that there was no dilative compression upon the cord structures. CONCLUSION: The results of this combined procedure, scar removal, dilation and implant delivery, led to thoughtful suggestions regarding the anatomy and the physiology of the inguinal canal. The procedural adhesiolysis during indirect inguinal hernia repair has always shown the well described concentric muscular arrangement formed by the internal oblique and transversus muscles. This circular-shaped muscular structure is often recognised as a static barrier that, due to weakness and/or together with other causes, fails in its role and allows indirect inguinal hernia protrusion. According to the results of our observations, we consider this concentric muscular complex as a dynamic formation: we will use the term "striated sphincter complex." Its steady tightening motion after divulsion and the insertion of a lamellar implant is always accompanied by a strong gripping action, which is not seen prior to divulsion. This indicates that it could correspond to a sphincter: the "inguinal sphincter." The impairment of this sphincter could be the cause of the inguinal canal's patency and the development of hernia.

Engineering substrate recognition in catalysis by cytochrome P450cam.

We have a continuing interest in applying the current knowledge of cytochrome P450cam substrate recognition to engineer the enzyme for the biotransformation of unnatural substrates with the long-term aim of applications in the synthesis of fine chemicals and bioremediation of environmental contaminants. Comparisons of the structure of target substrates with that of camphor, the natural substrate, led to the design of active-site mutants with greatly enhanced activity for the oxidation of chlorinated benzenes and selectivity of (+)-alpha-pinene oxidation. The crystal structures of the F87W/Y96F/V247L mutant with 1,3,5-trichlorobenzene or (+)-alpha-pinene bound have revealed the enzyme-substrate contacts and provided insights into the activity and selectivity patterns. The structures have also provided a novel basis for further engineering of P450cam for increased activity in the oxidation of the highly inert pentachlorobenzene and hexachlorobenzene, and increased selectivity of (+)-alpha-pinene oxidation.

Engineering the CYP101 system for in vivo oxidation of unnatural substrates.

The protein engineering of CYP enzymes for structure-activity studies and the oxidation of unnatural substrates for biotechnological applications will be greatly facilitated by the availability of functional, whole-cell systems for substrate oxidation. We report the construction of a tricistronic plasmid that expresses the CYP101 monooxygenase from Pseudomonas putida, and its physiological electron transfer co-factor proteins putidaredoxin reductase and putidaredoxin in Escherichia coli, giving a functional in vivo catalytic system. Wild-type CYP101 expressed in this system efficiently transforms camphor to 5-exo-hydroxycamphor without further oxidation to 5-oxo-camphor until >95% of camphor has been consumed. CYP101 mutants with increased activity for the oxidation of diphenylmethane (the Y96F-I395G mutant), styrene and ethylbenzene (the Y96F-V247L mutant) have been engineered. In particular, the Y96F-V247L mutant shows coupling efficiency of approximately 60% for styrene and ethylbenzene oxidation, with substrate oxidation rates of approximately 100/min. Escherichia coli cells transformed with tricistronic plasmids expressing these mutants readily gave 100-mg quantities of 4-hydroxydiphenylmethane and 1-phenylethanol in 24-72 h. This new in vivo system can be used for preparative scale reactions for product characterization, and will greatly facilitate directed evolution of the CYP101 enzyme for enhanced activity and selectivity of substrate oxidation.

Analysis of cyanobacterial toxins by physicochemical and biochemical methods.

Cyanobacteria (blue-green algae) produce a wide range of low molecular weight metabolites that include potent neurotoxins, hepatotoxins, and cytotoxins. The accumulation of such toxins in freshwaters, and in brackish and marine waters presents hazards to human and animal health by a range of exposure routes. A review is presented of developments in the detection and analysis of cyanobacterial toxins, other than bioassays, including application of physicochemical, immunoassays, and enzyme-based methods. Analytical requirements are considered with reference to recently derived guideline levels for the protection of health and to the availability, or otherwise, of purified, quantitative cyanobacterial toxin standards.

Colorimetric immuno-protein phosphatase inhibition assay for specific detection of microcystins and nodularins of cyanobacteria.

A novel immunoassay was developed for specific detection of cyanobacterial cyclic peptide hepatotoxins which inhibit protein phosphatases. Immunoassay methods currently used for microcystin and nodularin detection and analysis do not provide information on the toxicity of microcystin and/or nodularin variants. Furthermore, protein phosphatase inhibition-based assays for these toxins are not specific and respond to other environmental protein phosphatase inhibitors, such as okadaic acid, calyculin A, and tautomycin. We addressed the problem of specificity in the analysis of protein phosphatase inhibitors by combining immunoassay-based detection of the toxins with a colorimetric protein phosphatase inhibition system in a single assay, designated the colorimetric immuno-protein phosphatase inhibition assay (CIPPIA). Polyclonal antibodies against microcystin-LR were used in conjunction with protein phosphatase inhibition, which enabled seven purified microcystin variants (microcystin-LR, -D-Asp3-RR, -LA, -LF, -LY, -LW, and -YR) and nodularin to be distinguished from okadaic acid, calyculin A, and tautomycin. A range of microcystin- and nodularin-containing laboratory strains and environmental samples of cyanobacteria were assayed by CIPPIA, and the results showed good correlation (R2 = 0.94, P < 0.00001) with the results of high-performance liquid chromatography with diode array detection for toxin analysis. The CIPPIA procedure combines ease of use and detection of low concentrations with toxicity assessment and specificity for analysis of microcystins and nodularins.

An introduction to hemoglobin physiology.

Hemoglobin plays an important physiologic role, one that begins early in fetal development. The focus of this article is hemoglobin physiology. Developmental erythropoiesis, developmental stages of hemoglobin, and postnatal erythropoiesis and hemoglobin production are discussed. The function of hemoglobin, its affinity for oxygen, and the clinical significance of the oxyhemoglobin dissociation curve are also explored.

Neonatal cardiovascular pharmacology.

Neonates present with a variety of cardiovascular problems that require pharmacologic intervention. Pharmacologic manipulation of the ductus arteriosus and pharmacologic augmentation of cardiac output are the focus of this article. Guidelines for nursing assessment and clinical monitoring of neonates receiving cardiovascular drugs are included.

Cyanobacterial toxins: occurrence, modes of action, health effects and exposure routes.

Cyanobacterial toxins are produced by terrestrial- fresh-, brackish- and sea-water cyanobacteria of cosmopolitan occurrence. These toxins present acute and chronic hazards to human and animal health and are responsible for isolated, sporadic animal fatalities (mammals, fish, birds) each year. Human health problems are associated with the ingestion of, and contact with cyanobacterial blooms and their toxins. Modes of action of cyanobacterial neurotoxins, hepatotoxins and skin irritants are considered. Recent indications of the accumulation of cyanobacterial toxins in fish, their effect on crop plants and their association with the deaths of human dialysis patients are discussed. These findings and events indicate an incomplete understanding of the exposure routes of these natural toxins and the need for greater awareness of their occurrence and properties among users of waterbodies which are prone to cyanobacterial bloom development.

Recombinant tissue plasminogen activator.

The widespread use of indwelling intravascular catheters, such as central venous lines and umbilical vessel catheters, has resulted in an increased number of thrombotic complications and subsequently a growing need for specific thrombolytic therapy. The use of thrombolytic agents that have a high incidence of systemic fibrinolysis is of concern, however, especially in premature neonates. Tissue plasminogen activator is a locally acting thrombolytic agent that occurs naturally in the body. Tissue plasminogen activator can now be mass-produced through recombinant DNA technology. Reports of recombinant tissue plasminogen activator use in neonates are beginning to appear in the literature. This thrombolytic agent appears to be promising for the local lysis of clots within systemic coagulopathy. However, there is a need for controlled studies of thrombolytic agents in the neonatal population.

The national pain management guideline: implications for neonatal intensive care. Agency for Health Care Policy and Research.

A wide range of acute pain management strategies is used in various patient populations throughout the United States. A guideline, developed by an interdisciplinary panel convened by the Agency for Health Care Policy and Research, offers health care providers a "coherent yet flexible approach to pain assessment and management for use in daily practice." The goal of the guideline and application to daily practice in the NICU are described.

Relationship between inspiratory effort and breathlessness in pregnancy.

Using open-magnitude scaling, we compared the relationships between breathlessness, inspiratory esophageal pressure swing (delta Pes), and ventilation in pregnancy and postpartum. Thirteen healthy women performed progressive cycle exercise tests at 33 +/- 2 wk gestation and 12 +/- 3 wk postpartum. Pulmonary function and maximal transdiaphragmatic pressure did not change. Minute ventilation (VE) was greater in the third trimester. This increase was entirely due to the increase in tidal volume (VT; 0.74 +/- 0.18 vs. 0.54 +/- 0.18 liters at rest, P less than 0.01; 1.56 +/- 0.3 vs. 1.24 +/- 0.24 liters at 48 W, P less than 0.001). delta Pes (15.3 +/- 3.0 vs. 11.9 +/- 3.5 cmH2O at 48 W, P less than 0.01) and breathlessness (1.8 +/- 1.4 vs. 1.0 +/- 0.9 at 48 W, P less than 0.05) were greater in the third trimester. However, the relationships between VT and delta Pes and between delta Pes and breathlessness were identical in the two conditions. The VT-tidal abdominal volume (Vab) and Vab-tidal gastric pressure swing (delta Pga) relationships were similar in the two conditions. In conclusion, the relationship between delta Pes and breathlessness is the same in the third trimester and postpartum. The increased VE is responsible for the breathlessness in the third trimester. Despite progressive abdominal distension by the gravid uterus, the VT-Vab and Vab-delta Pga relationships were the same in the two conditions.