Nitrous oxide emissions from cow urine patches in an intensively managed grassland: Influence of nitrogen loading under contrasting soil moisture

In dairy grazing systems, livestock urine patches are hotspots that contribute to global warming, both directly through nitrous oxide (N₂O) emissions, and indirectly, through nitrate leaching. However, under warm-dry temperate environments, N₂O emission factors (EFs) have not been thoroughly evaluated, accounting for the influence of urinary nitrogen (N) concentration and urine volume, and emissions measurement approach through different urine application methods. Here we quantified and compared N₂O emissions and EFs on a moderately well-drained sandy loam soil from urine patches established in naturally expanding effective area (NEEA), representing urine volumes of 2, 3 and 4 L m^-2 (equivalent to urine -N loadings of 141, 211 and 282 kg N ha^-1), and using the uniformly wetted area (UWA) with urine applied at 10 L m^-2 (709 kg N ha^-1), under two different soil moistures (below field capacity, BFC; field capacity, FC). The results showed that cumulative N₂O emissions in the NEEA urine patches were 0.36-0.52 kg N₂O-N ha^-1 over 146 days (early-winter to late-spring). In the UWA urine patches, cumulative N₂O emissions were 2.3 times higher at FC (1.96 kg N₂O-N ha^-1) than BFC (0.87 kg N₂O-N ha^-1). The EFs were similar between UWA (0.09%) and NEEA (0.07-0.10%) at BFC but were significantly higher (P < 0.05-0.1) in UWA (0.26%) than NEEA (0.09-0.16%) at FC. The EFs in NEEA were not affected by urine-N loadings under BFC and FC, ranging between 0.07 and 0.16%. The relatively high versus low urine-N loadings in NEEA enhanced pasture herbage and N-uptake responses under both soil moistures. However, there were no differences in apparent N-use efficiency (ranging from 27 to 39%) across the treatments. The EFs observed in this study are much lower than the existing Australian cattle urine annual EF of 0.4%, and further examination to determine a more accurate EF for the industry is required.

A Global Perspective on Integrated Strategies to Manage Soil Phosphorus Status for Eutrophication Control without Limiting Land Productivity

Unnecessary accumulation of phosphorus (P) in agricultural soils continues to degrade water quality and linked ecosystem services. Managing both soil loss and soil P fertility status is therefore crucial for eutrophication control, but the relative environmental benefits of these two mitigation measures, and the timescales over which they occur, remain unclear. To support policies toward reduced P loadings from agricultural soils, we examined the impact of soil conservation and lowering of soil test P (STP) in different regions with intensive farming (Europe, the United States, and Australia). Relationships between STP and soluble reactive P concentrations in land runoff suggested that eutrophication control targets would be more achievable if STP concentrations were kept at or below the current recommended threshold values for fertilizer response. Simulations using the Annual P Loss Estimator (APLE) model in three contrasting catchments predicted total P losses ranging from 0.52 to 0.88 kg ha depending on soil P buffering and erosion vulnerability. Drawing down STP in all catchment soils to the threshold optimum for productivity reduced catchment P loss by between 18 and 40%, but this would take between 30 and 40+ years. In one catchment, STP drawdown was more effective in reducing P loss than erosion control, but combining both strategies was always the most effective and more rapid than erosion control alone. By accounting for both soil P buffering interactions and erosion vulnerability, the APLE model quickly provided reliable information on the magnitude and time frame of P loss reduction that can be realistically expected from soil and STP management. Greater precision in the sampling, analysis, and interpretation of STP, and more technical innovation to lower agronomic optimum STP concentrations on farms, is needed to foster long-term sustainable management of soil P fertility in the future.

Balancing water-quality threats from nutrients and production in Australian and New Zealand dairy farms under low profit margins

The loss of nitrogen (N) and phosphorus (P) from dairy-farmed land can impair water quality. Efforts to curtail these losses in Australia and New Zealand (Australasia) have involved a mixture of voluntary and regulatory approaches. In the present paper, we summarise the losses of N and P from Australasian dairy farms, examine the policy drivers used for mitigating losses and evaluate the effectiveness of contrasting approaches to implementing mitigations. Median losses for N and P were 27 and 1.6 kg/ha.year respectively, with a wide range of variation (3–153 kg N/ha.year and 0.3–69 kg P/ha.year) caused by a complex array of climate, soil types, flow paths, nutrient surpluses and land management factors. This complexity, coupled with the variable implementation of measures to mitigate losses, means that many voluntary programs to decrease losses have had uncertain or limited success. Although there is little or no formal regulation in Australia, regulation exists in New Zealand that requires regional authorities to implement the best strategy to improve water quality according to regional-specific characteristics. In testing a generalised approach to mitigation (priority given to those that are easy to implement) in four regions in New Zealand, we found that P could be mitigated quite cheaply, but N reductions required more measures, some of which are costly. Conversely, prioritising on the basis of mitigation cost-effectiveness for a specific nutrient will lead to more rapid reductions in losses of the target nutrient, but with fewer co-benefits for the non-target nutrient or other water pollutants, such as faecal microorganisms and sediment. This information will assist farmers in deciding how to meet a catchment target at least cost.

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.

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.

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.

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.

The impact of a dedicated trauma program on outcome in severely injured patients

BACKGROUND

In recent years, many trauma centers have been closing or scaling down their operations because of financial losses and lack of commitment by the relevant authorities.

OBJECTIVE

To investigate the effect of commitment to trauma and the establishment of a dedicated trauma program on injury outcome.

DESIGN

In 1992, a well-funded dedicated trauma program was implemented at the Los Angeles County--University of Southern California Medical Center, Los Angeles. We analyzed the outcome in severely injured patients (Injury Severity Score [ISS] > 15) before and after implementation of the program (1991 and 1993).

SETTING

Large, urban, level 1 trauma center.

PATIENTS

Patients with trauma and an ISS higher than 15.

RESULTS

There were 737 patients with an ISS higher than 15 in 1991 and 812 patients with an ISS higher than 15 in 1993. The overall mortality rate was 30% in 1991 and 24.5% in 1993 (P = .018), which is a reduction by 18.3%. In patients with blunt trauma and an ISS higher than 15, mortality was reduced by 33% (mortality rate of 31.1% in 1991 vs 20.8% in 1993) (P < .002). Mortality in patients with penetrating trauma and an ISS higher than 30 was reduced by 42.7% (mortality rate of 59.3% in 1991 vs 34% in 1993) (P = .019). There was also a trend toward lower permanent disabilities among survivors with an ISS higher than 15 (14.7% in 1991 vs 11.3% in 1993).

CONCLUSION

Commitment of financial and human resources for the establishment of a dedicated trauma program is a sound investment in terms of improved survival and fewer permanent disabilities in critically injured patients.

Cranioplasty with the Medpor porous polyethylene flexblock implant. Technical note

The authors describe the use of a porous polyethylene Flexblock implant for cosmetic cranioplasty. The implant may be used to cover any small- or medium-sized (< 8 cm) cranial defect, offering similar cosmetic results to standard alloplast cranioplasty while decreasing operation time. The porous implant design permits ingrowth of soft tissue and bone to increase implant strength and decrease the risk of infection. The Flexblock alloplast has been utilized in 25 cases with excellent cosmetic results and no implant-related complications.

The role of alloplastic skeletal modification in the reconstruction of facial burns

The external appearance of the face is largely dictated by its supporting facial skeleton. After an extensive thermal injury, the underlying facial skeleton may need to be either augmented or restored to maintain the functional and aesthetic appearance of the face. The factors that make a structural reconstruction difficult are poor vascularity and compliance of the scar tissue, extreme contractile forces of the scar, and unstable skin coverage. The use of an alloplast in the setting of facial burn scars may be one of the greatest challenges for an implant material. We reviewed our experience with the use of the Medpor porous polyethylene implant in facial burn reconstruction. This biomaterial has structural characteristics that allow for tissue ingrowth, yet it resists deformation by contractile forces. A total of 57 consecutive implants were placed in 24 patients with facial burns. Implants were used for the chin, the nose, the malar region, and as an ear framework. Patient follow-up ranged from 6 months to 3 years. Although 4 implants became exposed and 1 was thought to become infected, only 1 of the implants was removed. There were no other implant-related complications. We believe that skeletal modification is an important step for a successful facial burn reconstruction. Porous polyethylene offers a promising solution for the complex reconstructive problem of using an alloplast in the environment of a facial burn.

Craniofacial applications for the Medpor porous polyethylene flexblock implant

We describe use of flexblock, a newly designed Medpor porous polyethylene implant. This implant is ideally suited for repair of small to medium-sized cranial defects and correction of contour deformities. Medpor is used for a wide variety of maxillofacial procedures, and its properties make it an excellent choice for the cranium. It is a highly stable and somewhat flexible porous alloplast that has been shown to exhibit rapid soft-tissue and bone ingrowth. Flexblock, which was designed as an onlay for calvarial bone graft donor sites, has a smooth exterior surface and a series of conical ridges on its undersurface that enable easy bending, good contour adaptability, and suitable strength. We used the Medpor flexblock implant in 12 patients over 2 years for correction of contour deformities, cranial defects, and reconstruction of the supraorbital rim. There were no complications. Larger cranial defects and complex reconstructions can be performed using customized Medpor implants. The properties of Medpor and the flexblock design make this implant an excellent alternative to the existing methods of cranioplasty and cranial contour correction.

Coverage of bilateral lower extremity calcaneal fractures with osteomyelitis using a single split free gracilis muscle transfer

A case is presented in which a single gracilis muscle was split and used for free-tissue coverage of two sites in a patient with bilateral calcaneal fractures and posttraumatic osteomyelitis. Muscle-flap coverage of osteomyelitis and the use of the gracilis muscle for free-tissue transfer are discussed.

Increased fetoplacental active renin production in pregnancy-induced hypertension

Since pregnancy-induced hypertension is associated with impaired uteroplacental blood flow, we studied fetoplacental and maternal renin production in controls and subjects with pregnancy-induced hypertension. We measured total, active, and inactive (pro-) renin in maternal serum, fetal arterial and venous blood, and chorion homogenate in eight normotensive term patients and 18 patients with pregnancy-induced hypertension. No differences in active or prorenin were found in maternal blood from normal women or patients with pregnancy-induced hypertension. In contrast, fetal artery and vein, as well as chorionic tissue, contained significantly higher active renin in pregnancy-induced hypertension compared with normal subjects. No difference in fetal or chorionic prorenin was seen in the two groups. Thus active to total renin ratio was higher in the fetus and chorion of subjects with pregnancy-induced hypertension, which suggests enhanced active renin production. These results suggest that pregnancy-induced hypertension is associated with increased activity of the renin-angiotensin system in the fetoplacental unit, which is not reflected in the maternal circulation. This may be an attempt by the fetus and chorionic membranes to maintain vascular homeostasis in the face of altered uteroplacental blood flow.

The effect of mitoxantrone treatment in beagle dogs previously treated with minimally cardiotoxic doses of doxorubicin

Low-grade chronic cardiotoxicity as determined by myocardial biopsy specimens was induced in beagle dogs after four courses of doxorubicin hydrochloride (1.64 mg/kg, 34.0 mg/sq m) given intravenously once every 3 weeks. After this initial treatment, these dogs were separated into three groups. Two groups received six courses of mitoxantrone (0.25 mg/kg, 5 mg/sq m) commencing at 7 weeks or 19 weeks after the final doxorubicin treatment. The third group was treated with six additional courses of doxorubicin after an interval of 7 weeks. Up to seven sequential endomyocardial biopsies were performed to monitor the myocardial changes which were observed after the initial doxorubicin treatment. The low-grade cardiotoxic changes progressed for at least 7-11 weeks without any additional doxorubicin treatment, and stabilized or even partially reversed after 19 weeks of a treatment-free period. Dogs that received additional doxorubicin demonstrated progressive cardiotoxicity, associated with clinical signs, that resulted in death after a total of seven to ten courses of treatment (12-16 mg/kg, 238-340 mg/sq m cumulative dose). In dogs treated with doxorubicin followed by mitoxantrone after a 19-week treatment-free period, myocardial changes were shown to have stabilized and/or partially regressed. This study indicated that in beagle dogs four courses of doxorubicin (7 mg/kg, 136 mg/sq m cumulative dose) are the threshold dose at which non-life-threatening cardiotoxicity occurs. Residual toxic effects of doxorubicin may be erroneously interpreted as adverse findings attributable to other agents given subsequently during the susceptible period, ie, prior to stabilization of the myocardium. Mitoxantrone given after stabilization of doxorubicin-induced low-grade myocardial changes did not show additive or synergistic effects.