Is the development of desalination compatible with sustainable development of the Arabian Gulf?

The development of desalination has been essential to the rapid economic development of the countries bordering the Arabian Gulf. The current production capacity of sea water desalination plants drawing water from Gulf is over 20 million m3 day-1, which may rise to 80 million m3 day-1 by 2050. Whilst supporting aspects of sustainable development related to water and sanitation, desalination impacts the marine environment through impingement and entrainment of organisms in intakes, and through thermal, brine and chemical discharges. This may compromise other objectives for sustainable development related to sustainable use of the oceans. Under business as usual scenarios, by 2050, the impact of individual desalination plants will combine causing a regional scale impact. Without mitigating actions to avoid the business as usual scenario, by 2050, desalination in combination with climate change, will elevate coastal water temperatures across more than 50% of the Gulf by at least 3 °C, and a volume of water equivalent to more than a third of the total volume of water between 0 and 10 m deep will pass through desalination plants each year. This will adversely impact the coastal ecosystem of the Gulf, with impacts on biodiversity, fisheries and coastal communities and may cause potential loss of species and habitats from the Gulf. Given the significant implications of these preliminary findings, and in light of the precautionary approach to management, it is recommended that mitigating options addressing behavioural, regulatory and technological change are rapidly evaluated and implemented to avoid the development of desalination in the region along a business as usual pathway, and multidisciplinary research studies should be conducted to reduce uncertainty in predictions of future impacts.

Breast cancer after augmentation mammoplasty.

BACKGROUND: It is thought that implants interfere with breast cancer diagnosis and that cancers in women who have had breast augmentation carry a worse prognosis. METHODS: A prospective breast cancer database was reviewed, comparing augmented and nonaugmented patients for details of histology, palpability, tumor size, nodal status, mammographic status, receptor status, nuclear grade, stage, and outcome. RESULTS: Ninety-nine cancers in augmented women and 2857 cancers in nonaugmented women were identified. Among these women, mammography was normal in 43% of those who had had augmentation and in 5% of those who had not. Augmented women were more likely to have palpable cancers (83% vs. 59%) and nodal involvement (48% vs. 36%), and less likely to have ductal carcinoma in situ (DCIS) (18% vs. 28%). When comparing only women younger than 50, the differences in invasiveness and nodal status lost significance. Cancers diagnosed in the 1990s were more likely to be nonpalpable and noninvasive than those diagnosed in the 1980s. This trend was more pronounced in the augmented population. CONCLUSIONS: Augmented patients were more likely to have palpable cancers, although the overall stage and outcome were similar to those of nonaugmented women. Although there have been significant improvements in our ability to diagnose early breast cancer over the past two decades, mammography continues to be suboptimal in augmented women.

The use of 5% mafenide acetate solution in the postgraft treatment of necrotizing fasciitis.

Twenty-nine patients with necrotizing fasciitis who were treated with 5% mafenide acetate solution (MAS) as an adjunct after grafting were compared with 45 patients treated without MAS. Statistical analysis of differences was obtained through P values by chi2 testing. The MAS+ (M) and MAS- (C) groups were similar in percent skin deficit (M = 7.5%; C = 9.8%), with the extremity being the most common area of infection. Streptococcus was the most common single organism but polymicrobial infections were the most prevalent (M = 48%; C = 58%). Patients with necrotizing fasciitis treated with MAS had fewer debridements per patient (M = 3.7; C = 5.4), fewer closure procedures (average per patient: M = 1.2; C = 1.73) and a higher percent of first-time closures (83 vs 59%; chi2 = 4.26; P = 0.039). There is a trend toward a lower mortality rate (3.4 vs 13%; chi2 = 2.00; P = 0.158). We conclude that MAS is a useful adjunct in necrotizing fasciitis wound care protocols.

The Bloch equations in high-gradient magnetic resonance force microscopy: theory and experiment.

We report theory and observations of paramagnetic resonance in a measured field gradient of 44,000 T per meter by the technique of magnetic resonance force microscopy (MRFM). Resonance was induced in a dilute solid solution of diphenylpicrylhydrazyl in polystyrene at 77 and 10 K by an amplitude-modulated microwave field. This modulated the force between resonant sample spins and a micrometer-scale SmCo magnetic tip on a force microscope cantilever. The force signals were typically of order 10 fN, and were detected above a thermal noise floor of 80 aN per root hertz at 10 K, equivalent to a magnetic moment noise of 200 micro(B) per root hertz of bandwidth. Resonance saturation was readily observed. Starting with the Bloch equations, we derived simple analytic expressions for the predicted cantilever signal amplitudes and T(1)-dependent phase lags, valid at low microwave power levels. For power levels below saturation, the data were in good agreement with the Bloch equation predictions, while above saturation the measured force increased more slowly with power than predicted. Several ESR mechanisms which might lead to non-Bloch dynamics in the MRFM environment are reviewed. Spin-relaxation mechanisms are also reviewed. A detailed description of the experimental apparatus is offered.

Duration of antibiotic prophylaxis in high-risk patients with penetrating abdominal trauma: a prospective randomized trial.

To evaluate the effect of varying durations of antibiotic prophylaxis in trauma patients with multiple risk factors for postoperative septic complications, a prospective randomized trial was undertaken at an urban level I trauma center. The inclusion criteria were full-thickness colon injury and one of the following: (1) Penetrating Abdominal Trauma Index > 25, (2) transfusion of 6 units or more of packed red blood cells, or (3) more than 4 hours from injury to operation. Patients were randomly assigned to a short course (24 hours) or a long course (5 days) of antibiotic therapy. All patients received 2 g cefoxitin en route to the operating room and 2 g intravenously piggyback every 6 hours for a total of 1 day vs. 5 days. Sixty-three patients were equally divided into short-course (n = 31) and long-course (n = 32) therapy. This was a high-risk patient population, as assessed by the mean Penetrating Abdominal Trauma Index (33), number of patients with multiple blood transfusions (51 of 63; 81%), number of patients with an Injury Severity Score greater than 15 (37 of 63; 59%), number of patients with destructive colon wounds requiring resection (27 of 63; 43%), and number of patients requiring postoperative critical care (37 of 63; 59%). Differences in intra-abdominal (1-day, 19%; 5-days, 38%) and extra-abdominal (1-day, 45%; 5-days, 25%) infection rates did not achieve statistical significance. There continues to be no evidence that extending antibiotic prophylaxis beyond 24 hours is of benefit, even among the highest risk patients with penetrating abdominal trauma. A large, multi-institutional trial will be necessary to condemn this common practice with statistical validity.

High-frequency percussive ventilation improves oxygenation in patients with ARDS.

STUDY OBJECTIVES: To evaluate changes in respiratory and hemodynamic function of patients with ARDS and requiring high-frequency percussive ventilation (HFPV) after failure of conventional ventilation (CV). DESIGN: Retrospective case series. SETTING: Surgical ICU (SICU) and medical ICU (MICU) of an academic county facility. MEASUREMENTS AND RESULTS: Thirty-two consecutive patients with ARDS (20 from SICU, 12 from MICU) who were unresponsive to at least 48 h of CV and were switched to HFPV were studied. Data on respiratory and hemodynamic parameters were collected during the 48 h preceding and the 48 h after institution of HFPV and compared. Between the period of CV and the period of HFPV, the ratio of PaO2 to the fraction of inspired oxygen (F(IO2)) increased ([mean+/-SE] 130+/-8 vs. 172+/-17; p = 0.027), peak inspiratory pressure (PIP) decreased (39.5+/-1.7 vs. 32.5+/-1.9 mm Hg; p = 0.002), and mean airway pressure(MAP) increased (19.2+/-1.2 vs. 27.5+/-1.4 mm Hg; p<0.001). The rate of change of PaO2/F(IO2) per hour was also significantly improved between the two periods. The same changes in PaO2/F(IO2), PIP, and MAP were observed when the last value recorded while the patients were on CV was compared with the first value recorded after 1 h of HFPV. This improvement was sustained but not amplified during the hours of HFPV. The patterns of improvement in these three parameters were similar in SICU and MICU patients as well as in volume-control and pressure-control patients. There were no changes in hemodynamic parameters. CONCLUSION: The HFPV improves oxygenation by increasing MAP and decreasing PIP. This improvement is achieved soon after institution of HFPV and is maintained without affecting hemodynamics.

Angiotensin II improves random-flap viability in a rat model.

Angiotensin II (AII) is a naturally occurring peptide that has been shown to be angiogenic, cause the proliferation of several primary cell types (including endothelial cells), accelerate the repair of dermal injuries, and increase production of growth factors and extracellular matrix. The effect of a single administration of AII on the viability and vascularity of a random flap was assessed in a rat model. In the control model, the viability of the distal portion of the flap was reduced consistently by postoperative day 8. Initially, AII was administered in an aqueous vehicle (phosphate-buffered saline [PBS]) and a viscous vehicle (10% carboxymethyl cellulose [CMC]). Administration of 1 mg per milliliter AII in PBS did not affect the viability of random flaps (1.2 x 7 cm) in this animal model. However, a single administration of a higher dose of AII in PBS (10 mg per milliliter) or 1 mg per milliliter AII in the CMC vehicle resulted in 67% of the grafts being fully viable at postsurgical day 12, in contrast to vehicle-treated control flaps, none of which were fully viable at day 12. Furthermore, the portion of the flap that was viable was increased significantly (p < or = 0.05). Subsequently, a study was conducted to assess the dose-response curve for AII in a CMC vehicle in this rat model. As the dose of AII was reduced, the percentage of animals with fully viable flaps and the percentage of the flap that was viable decreased correspondingly. Administration of 0.03 mg per milliliter AII and greater increased significantly (p < or = 0.05) the viability of the flaps. In conclusion, AII appears to be highly efficacious in increasing the percentage of distal flap surface area survival when administered as a single topical dose to the wound bed.

Cold injury from pressurized liquid ammonia: a report of two cases.

Patients exposed to pressurized liquids or gases present unique diagnostic and treatment challenges to the Emergency Physician. The potential for injury depends upon the properties of the chemical in addition to the thermodynamic effects from exposure to a pressurized substance. We present two cases of exposure to pressurized ammonia during an industrial accident. One patient's symptoms were consistent with an ammonia alkali burn, whereas the other patient's symptoms were more characteristic of a significant thermal injury caused by the rapid expansion and evaporation of a pressurized liquid.

Black-pigmented bacteria in coronal and apical segments of infected root canals.

Black-pigmented bacteria (BPB) have been associated with infections of endodontic origin. The purpose of this study was to culture and identify BPB from the apical and coronal segments of infected root canals to understand better their ecological relationships. Teeth with a periapical radiolucency were extracted and immediately placed in reduced transport fluid for transport to an anaerobic chamber. Of 18 sampled roots, 12 were positive for the growth of BPB. Eight of the 12 roots with BPB had a carious exposure of the pulp chamber. Seven roots had Prevotella nigrescens in both the apical and the coronal segments. Six of these seven teeth had carious exposures of the pulp chamber. Of the 12 roots infected with BPB, six roots had two different species of BPB, with P. nigrescens always being one of the species. P. nigrescens was the most often isolated BPB from both the coronal and apical segments of infected root canals.

Multicenter study of noninvasive monitoring systems as alternatives to invasive monitoring of acutely ill emergency patients.

BACKGROUND: Recent reports showed lack of effectiveness of pulmonary artery catheterization in critically ill medical patients and relatively late-stage surgical patients with organ failure. Since invasive monitoring requires critical care environments, the early hemodynamic patterns may have been missed. Ideally, early noninvasive hemodynamic monitoring systems, if reliable, could be used as the "front end" of invasive monitoring to supply more complete descriptions of circulatory pathophysiology. OBJECTIVES: To evaluate the accuracy and reliability of noninvasive hemodynamic monitoring consisting of a new bioimpedance method for estimating cardiac output combined with arterial BP, pulse oximetry, and transcutaneous PO2 and PCO2; we compared this system of noninvasive monitoring with simultaneous invasive measurements to evaluate circulatory deficiencies in acutely ill patients shortly after hospital admission where invasive monitoring was not readily available. We also preliminarily explored early differences in temporal hemodynamic patterns of survivors and nonsurvivors. DESIGN AND SETTING: Prospective comparison of simultaneous invasive and noninvasive measurements of circulatory function with retrospective analysis of data in university-run county hospitals, university hospitals and affiliated teaching hospitals, and a community private hospital. PATIENTS: We studied 680 patients, including 139 severely injured or hemorrhaging patients in the emergency department (ED), 129 medical (nontrauma) patients on admission to the ED, 274 high-risk surgical patients intraoperatively, and 138 patients recently admitted to the ICU. RESULTS: A new noninvasive impedance device provided cardiac output estimations under conditions in which invasive thermodilution measurements were not usually applied. There were 2,192 simultaneous bioimpedance and thermodilution cardiac index measurements; the correlation coefficient, r = 0.85, r2 = 0.73, p < 0.001. The precision and bias was -0.124+/-0.75 L/min/m2. Both invasive and noninvasive monitoring systems provide similar information and identified episodes of hypotension, low cardiac index, arterial hemoglobin desaturation, low transcutaneous O2, high transcutaneous CO2, and low oxygen consumption before and during initial resuscitation. The limitations of noninvasive systems were described. CONCLUSIONS: Noninvasive monitoring systems gave continuous displays of physiologic data that provided information allowing early recognition of low flow and poor tissue perfusion that were more pronounced in the nonsurvivors. Noninvasive systems may be acceptable alternatives where invasive monitoring is not available.

Application of TEV Protease in Protein Production.

In many cases, the analysis of a specific protein is impeded by the inability to purify large amounts of it from a native source. Proteins of interest may be present in minute quantities and/or purification may be plagued with technical problems. Recombinant DNA methodologies have enabled researchers to circumvent some of these limitations by producing and purifying large quantities of protein in a nonnative system. Various systems and strategies have been successfully employed, depending on the specific protein of interest and the desired use of the final end product (antibody production, crystallography studies etc.). This chapter reviews some common methods for the production of recombinant fusion proteins and specifically describes a versatrle method for the removal of affinity tags from recombinant fusions using a highly purified proteinase with an unparalleled degree of specificity. This proteinase, from the genome of tobacco etch virus (TEV), demonstrates specific proteolytic activity under a wide range of parameters (salt, temperature, pH), making it an excellent choice for cleavage of fusion proteins (1,2).

Histologic alterations in dermal repair after thermal injury effects of topical angiotensin II.

Previously, we determined that quantitative assessment of epithelialization of the burn site could be performed using quantitative immunohistochemistry with an antibody to the protein cyclin. In this study, the effect of administration of angiotensin II (AII) on two histologic parameters of healing-the number of vascular channels at the burn site and the number of cells proliferating in hair follicles at the edge of the burn and within the burn-were evaluated. Beginning on day 4, vascular channels were noted within the burn site. Significantly more channels were noted in the burns treated with AII than those treated with placebo. With the exception of 3 postinjury days, this increase continued through day 17. Thereafter, the number of vascular channels peaked, and no differences were noted between control and treated burns. The number of cells proliferating in the hair follicle was also evaluated. At the edge of the burn, on average, 126 cells per microscope field (10x) were undergoing proliferation in the AII-treated burn on days 1 through 16 after burn injury. This is approximately a 50% increase over the number of cells proliferating in the placebo-treated burns. On day 12 (approximately 5 days before that observed in control burns), this AII-dependent proliferative response began to increase and peaked on day 19 at a level comparable to control. Thereafter, the proliferative response remained at this level through day 28. Within the area of the burn on days 1 through 15, 21 cells per medium power field on average (approximately 50% more than control) were undergoing proliferation. As on the edge of the burn, an AII-dependent increase in the number of cells proliferating in the hair follicles was observed during the latter phase of healing (on day 16 after the initiation of injury). However, unlike the edge of the burn, administration of AII led to a continued increase (approximately 50%) in the number of cells per field undergoing proliferation. AII increased neovascularization and cellular proliferation after burn injury. Through an increase in these two cellular events, AII may in turn accelerate healing of tissues after thermal injury.

Necrotizing fasciitis of the face.

Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with high morbidity and mortality rates. Its occurrence in the head and neck region is uncommon, the majority of reported cases being limited to involvement of the neck, usually from infections of dental or pharyngeal origin. Involvement of the face from NF is rare; only 35 such cases have been reported in the literature since 1960. It is not only associated with a high mortality but can also result in severe disfigurement of the face, posing challenging reconstructive problems. Successful management of facial NF requires early diagnosis, prompt institution of broad spectrum antibiotics, aggressive surgical debridement to control the infection, and reconstruction of the resultant soft tissue defects. This report describes four additional cases of facial necrotizing fasciitis. One of the four patients died as a result of sepsis and multi-organ system failure. Two of the three surviving patients had significant facial disfigurement. A comprehensive review of the facial NF cases reported in the literature is also provided. Based on our experience with facial NF and the results of all previous case reports, the clinical manifestations, pathogenesis, and management of this disease are discussed.

Expression of cyclin protein after thermal skin injury in a guinea pig model.

In this study, an immunohistochemical stain for cyclin was used to quantitate proliferating elements in hair follicles at the edge of and within thermal burn areas. Biopsy specimens from thermal injury in the guinea pig (day 1 through day 28) were sectioned and stained with MIB-1 antibody, which recognizes cyclin, a protein expressed during epithelial cell proliferation. At the edge of the burn, 89 +/- 6.1 (SD) cells per medium power field (x 10, mpf) were MIB-1-positive on days 1 through 16. On day 17, the number of positive cells increased, reaching peak values on days 20 to 28 (271 +/- 12.7 cells/mpf). Within the burn, minimal staining was observed from day 1 to day 15 (12.7 +/- 1.6 cells/mpf). Thereafter the number of MIB-1-positive cells increased and plateaued with an average of 96.4 +/- 9.0 cells/mpf on days 20 through 28. In conclusion, immunohistochemical staining of dermal biopsy specimens with MIB-1 antibody may provide a quantitative method for the evaluation of tissue damage and healing after thermal injury.

Reconstruction of the skull base and cranium adjacent to sinuses with porous polyethylene implant: preliminary report.

Surgical reconstruction of the skull base and cranium adjacent to open paranasal sinuses with alloplastic materials is problematic secondary to an increased risk of implant infection in these locations. The authors report their initial experience with the use of a porous polyethylene implant for closure of defects in these locations in 20 patients, in 14 of these with the implant placed in direct contact with the mastoid or paranasal simuses. The implant is flexible, which facilitates surgical reconstruction of the cranial base, and porous in nature, which enhances soft tissue and bone ingrowth in decrease the risk of infection. The implant is radiolucent on plain roentgenograms and CT, and produces no imaging artifact on MRI. The implant was utilized for a variety of skull base of cranium adjacent to sinus reconstructive applications with no infectious complications, with a follow-up period ranging from 8 to 50 months. This preliminary experience suggests that the alloplast may be a useful adjunct in skull base reconstruction, and further evaluation of its use in this application is warranted.

Multiple viral determinants affect seed transmission of pea seedborne mosaic virus in Pisum sativum.

Two pea seedborne mosaic potyvirus (PSbMV) isolates, P-1 DPD1 (P-1), which is highly seed-transmitted, and P-4 NY (P-4), which is rarely seed-transmitted, and chimeras between P-1 and P-4 were analysed to map the viral genetic determinants of seed transmission. Infectivity of chimeric viruses was evaluated by inoculating Pisum sativum with RNA transcribed in vitro from recombinant full-length cDNA clones. The chimeric viruses that were used demonstrated that a genomic segment encoding the 49 kDa protease and putative RNA polymerase was responsible for symptom induction. Attempts to determine transmission of the chimeric viruses in P. sativum cultivars known to transmit P1 at high frequencies showed that seed transmission is a quantitative character influenced by multiple viral determinants. Seed transmission frequency did not correlate with accumulation of virus in vegetative tissue. The 5' 2.5 kb of the 10 kb PSbMV genome had a major influence on the seed transmission frequency and was analysed further. This showed that, while the helper-component protease was a major determinant of seed transmission, the potyviral P1 -protease exerted no measurable influence.

Left renal vein hypertension as a cause of persistent gross hematuria.

Left renal vein hypertension as a source of persistent gross hematuria has been described in the literature. This type of hematuria is postulated to result from an elevation of left renal vein pressure leading to calyceal-venous communications. We report a case of left renal vein hypertension in which surgical and radiologic findings identify the cause of the hypertension as an aberrant peripheral nerve. To our knowledge, this etiology has never been described. A review of the literature with emphasis on the pathophysiology of renal-vein hypertension is also presented.

The complexities of managing severe burns with associated trauma.

A high incidence of severe inhalation injuries can be expected in the combined injury patient. The initial management remains attention to the ATLS priorities of airway, breathing, and circulation, with prompt and safe transfer to a regional center of excellence. The treatment of either the burn or the associated injuries may be compromised by their combined presence, and a team approach is essential to their optimal management. Circulatory management goals based on oxygen consumption and delivery allow greater understanding and control of the physiologic demands placed on the patient by the disease process. The management of inhalation injury and ARDS is at an exciting turning point in history, and we now have in hand and use many techniques that allow salvage of these mortal conditions. Pain management is essential to humane care and requires frequent assessment and patient control to be effective. Rehabilitation of the burn and trauma patient starts on the day of injury and requires team dedication to the areas of greatest morbidity early in the planning of surgical priorities and physical therapy.