Fate of nitrogen in French human excreta: Current waste and agronomic opportunities for the future

Nitrogen (N) is essential for plant growth and protein synthesis but global reactive N losses, mainly from food systems, induce strong environmental impacts. N losses after human excretion are often overlooked because, in Western societies, they partly occur as inert N2, following denitrification in wastewater treatment plants (WWTP), and losses in waters are often small compared to diffuse agricultural emissions. Yet N from human excretions could be used for crop fertilization, potentially with very high recycling rates via source separation. In this study we use unique operational data from the ∼20,000 French WWTPs to produce a N mass-balance of excretions in the French sanitation system. Even though 75 % of WWTPs' sludge is spread on crops, only 10 % of the excreted N is recycled and 50 % of N is lost to the atmosphere, mainly through WWTP nitrification-denitrification. The remaining 40 % ends up in water or in diffuse losses in the ground, of which about half is lost outside of the WWTPs' discharge system, through sewers storm water and individual autonomous systems. While WWTPs removal efficiency increased in the 2000s, it has been followed by a decade of stagnation, reaching 70 % at the national level. This national average hides regional discrepancies, from 60 to 85 % in the 6 French water agencies basins. These differences closely correlate with the classification as "N sensitive areas" and is mainly due to large WWTPs which handle most of the N load. Recycling all N in excretions could supply 10 % of domestic protein consumption in the current French food system, and up to 30 % if it is prioritized towards crop production for human consumption. Redesigning the food system (decrease of nutrient losses, more plant-based diets) could further increase this contribution.

Corneal First Surface Optical Aberrations and Visual Performance

PURPOSE

Wavefront analysis has demonstrated that refractive surgery-induced corneal first surface aberrations are large, are dominated by symmetric aberrations (spherical-like aberrations), and are correlated to measures of visual performance. It is not clear whether the correlation between corneal first surface aberrations and visual performance can be generalized to other corneal conditions where large asymmetric aberrations (coma-like aberrations) may dominate the aberration structure. The purpose of the research reported here was to determine the general utility of corneal first surface wavefront analysis in predicting visual performance.

METHODS

Patients were 13 normals and 78 patients with a variety of corneal conditions including surgically removed pterygia, penetrating keratoplasty, keratoconus, radial keratotomy, laser in situ keratomileusis, and others. Videokeratographs were taken for all patients and used to calculate corneal first surface wavefront variance for 3 and 7 mm pupils. Similarly, visual performance was quantified by measurements of contrast sensitivity and high and low contrast acuities through both 3 and 7 mm pupils.

RESULTS

Statistically significant correlations existed between all three measures of visual performance and the corneal wavefront variance. All relationships were stronger for the 7 mm diameter-pupil condition than the 3 mm pupil.

CONCLUSION

Regardless of the cause, corneas with increased wavefront variance showed a quantifiable decrease in visual performance that was pupil size dependent.

Saccular outpouchings of an ascending aortic aneurysm: transesophageal echocardiographic appearance

The differential diagnosis of cavities in the ascending aorta includes pseudoaneurysms, intimal flaps, and abscesses. We describe the transesophageal echocardiographic and pathologic appearance of a fusiform ascending aortic aneurysm that contained atypical outpouchings that were initially confused with an intimal flap. Awareness of this unreported abnormality and its echocardiographic features will avoid the misdiagnosis of more serious aortic pathology such as acute aortic dissection or infective endocarditis.

Low-dose intraocular tissue plasminogen activator treatment for traumatic total hyphema, postcataract, and penetrating keratoplasty fibrinous membranes

Tissue plasminogen activator (tPA) has been used to treat severe postcataract and vitrectomy fibrinous membranes, but intraocular bleeding has occurred with doses of 25 micrograms or higher. We report three patients, one with nonclearing total hyphema and uncontrollable intraocular pressure and two with severe fibrinous membrane formation, who had treatment with low-dose (4 micrograms to 6 micrograms) intraocular tPA. Although the fibrinous membranes or hyphema resolved in all three patients, they recurred and bleeding that required additional treatment occurred in one patient. Intraocular low-dose tPA may minimize the risk of corneal and retinal toxicity and may be considered an alternative treatment in intractable cases. However, secondary intraocular hemorrhage can occur, and the timing between the initial vascular injury, treatment with tPA, and subsequent bleeding may reduce the risk of further hemorrhaging.

Penetrating keratoplasty and anterior segment reconstruction for severe ocular trauma

The principles for management of acute ocular trauma are also applicable to the subsequent reconstruction of the anterior segment. As with the primary repair of ocular trauma, meticulous anatomical restoration during reconstructive surgery minimizes secondary complications and enhances the visual prognosis. Anterior segment reconstruction may then involve procedures such as stripping of corneal pannus, removal of lens and vitreous remnants, iris and angle reconstruction, intraocular lens implantation, and penetrating keratoplasty. A total of 39 consecutive cases of severe ocular trauma, which had undergone penetrating keratoplasty and anterior segment reconstruction, were evaluated for visual outcome, graft survival, and secondary complications. Post-operatively, 49% of eyes achieved > 20/100 as compared with 10% before surgery, and 72% improved by at least two Snellen lines. In all, 31 (80%) initial keratoplasties remained clear, as did all 4 subsequently regrafted corneas, for an overall keratoplasty success rate of 90%. Elevated intraocular pressure occurred postoperatively in 18 eyes (46%), and among these, 10 of 13 eyes (77%) had preoperative glaucoma, whereas 8 of 26 (31%) did not (P < 0.015). Peripheral anterior synechiae could be anatomically corrected at surgery in 80% of cases (24 of 30 eyes). Thus, despite major trauma and a high prevalence of glaucoma, both the visual and the anatomical improvements were highly satisfactory and without severe complications.

Penetrating keratoplasty and anterior segment reconstruction for severe ocular trauma

The authors reviewed 39 consecutive cases of severe ocular trauma that had undergone penetrating keratoplasty plus anterior segment reconstruction and evaluated visual outcome, graft survival, and secondary complications. Postoperatively, 49% of eyes achieved visual acuity of 20/100 or better compared with 10% before surgery, and 72% improved at least 2 Snellen lines. With a mean follow-up of 23 months, 31 (80%) initial keratoplasties remained clear, and all 4 subsequently re-grafted corneas maintained clarity, for an overall keratoplasty success rate of 90%. Elevated intraocular pressure occurred postoperatively in 18 eyes (46%), and, among these, 10 of 13 eyes (77%) had preoperative glaucoma, whereas 8 of 26 (31%) did not (P less than or equal to 0.015). Preoperative anterior synechiae could be anatomically corrected at surgery in 80% of cases (24 of 30 eyes). In 7 cases with persistent synechiae, 6 (86%) were associated with glaucoma (P less than or equal to 0.025). Retinal detachment occurred in one case. Thus, despite major trauma and a high prevalence of glaucoma, both the visual restoration and anatomic reconstruction achieved were satisfactory and without severe complications.

Microbial contamination of in-use ocular medications

Two hundred twenty in-use medications from 101 patients with nonmicrobial ocular surface disease were studied by culturing the bottle caps, a drop produced by simple inversion, and the interior contents removed sterilely. Conjunctival cultures were taken from these patients and 50 age-matched controls. Pathogenic organisms were harvested from conjunctivae significantly more frequently (P less than .01) from cases (34 of 101) than from controls (five of 50). Sixty-four medications (29%) had microorganisms cultured from at least one medication site. Gram-negative organisms were significantly more likely (P less than .00001) to be isolated from all medication sites than gram-positive organisms. Additionally, when isolated from medication sites, the gram-negative organisms were highly likely to be cultured from the conjunctiva as well. This was not true for pathogenic gram-positive organisms. We conclude that a cycle of contamination between in-use medications and conjunctivae may represent an important risk factor for microbial keratitis in patients with ocular surface disease.

Clinical and histopathologic studies of two families with lattice corneal dystrophy and familial systemic amyloidosis (Meretoja syndrome)

Lattice corneal dystrophy associated with familial systemic amyloidosis (Meretoja syndrome) has rarely been described other than in patients of Finnish origin. The authors report two North American patients with this disease who manifest blepharochalasis, lattice corneal dystrophy, open-angle glaucoma, and cranial neuropathy. In one patient, a corneal intraepithelial and subepithelial pseudodendrite was managed by superficial keratectomy, and this same patient benefited from surgical brow suspension for facial muscular weakness. In the second patient, penetrating keratoplasty was complicated by a neurotrophic persistent epithelial defect. Corneal tissue from both superficial keratectomy and penetrating keratoplasty exhibited ultrastructurally characteristic amyloid filaments and associated elastoid material. Transmission electron microscopy of conjunctiva and skin biopsies similarly revealed amyloid deposits associated with most basement membranes, the perineurium and endoneurium of most peripheral nerves, and the intima and media of arteries. By immunoperoxidase staining, the corneal amyloid deposits were positive for the amyloid P-component protein but negative for the nonimmunoglobulin amyloid A protein and prealbumin. Serum prealbumin and amyloid A related protein were normal.

Conjunctival autograft for primary and recurrent pterygia: surgical technique and problem management

The surgical technique and postoperative problem management of conjunctival autograft transplantation for advanced primary and recurrent pterygium are reviewed. Problems such as graft edema, corneoscleral dellen, and epithelial inclusion cysts infrequently occur. Corneal astigmatism, Tenon's granuloma, retraction and/or necrosis of the graft, and muscular disinsertion are even less frequently encountered. Limbal-conjunctival autograft for recalcitrant recurrent cases is proposed.

Corneal surface irregularities and episodic pain in a patient with mucolipidosis IV

Mucolipidosis IV is a lysosomal storage disease characterized by prominent involvement of the corneal epithelium. A 5-year-old boy with mucolipidosis IV experienced recurrent episodes of severe ocular pain, tearing, and ipsilateral facial flushing. This was suggestive of reflex sympathetic dystrophy, a syndrome of pain and sympathetic hyperactivity. The examination revealed marked corneal surface irregularities, corresponding to massive accumulations of intracytoplasmic storage material in the epithelium. Episodic pain in patients with mucolipidosis IV is an important symptom, presumably reflecting the distinctive corneal ultrastructural abnormality in this disease.

Surgical treatment of human bites of the upper eyelid

Human bites of the upper eyelid are extremely rare. Few reports have been published on the surgical management of such injuries, and they have dealt mainly with those cases in which the avulsed tissue segment is available for reconstructive surgery. This article reports on a case of human bite injury of the upper eyelid with more than 50% full-thickness loss of tissue, in which the missing segment was not available for reconstruction.