Effects of plant diversity on species-specific herbivory: patterns and mechanisms.

Invertebrate herbivory can shape plant communities when impacting growth and fitness of some plant species more than other species. Previous studies showed that herbivory varies among plant species and that species-specific herbivory is affected by the diversity of the surrounding plant community. However, mechanisms underlying this variation are still poorly understood. In this study, we investigate how plant traits and plant apparency explain differences in herbivory among plant species and we explore the effect of plant community diversity on these species-specific relationships. We found that species differed in the herbivory they experienced. Forbs were three times more damaged by herbivores than grasses. Variability within grasses was caused by differences in leaf dry matter content (LDMC). Furthermore, higher plant diversity increased herbivory on 15 plant species and decreased herbivory on nine species. Variation within forb and grass species in their response to changing plant diversity was best explained by species' physical resistance (LDMC, forbs) and biomass (grasses). Overall, our results show that herbivory and diversity effects on herbivory differ among species, and that, depending on the plant functional group, either species-specific traits or apparency are driving those differences. Thus, herbivores might selectively consume palatable forbs or abundant grasses with contrasting consequences for plant community composition in grasslands dominated by either forbs or grasses.

Plant functional trait response to environmental drivers across European temperate forest understorey communities.

Functional traits respond to environmental drivers, hence evaluating trait-environment relationships across spatial environmental gradients can help to understand how multiple drivers influence plant communities. Global-change drivers such as changes in atmospheric nitrogen deposition occur worldwide, but affect community trait distributions at the local scale, where resources (e.g. light availability) and conditions (e.g. soil pH) also influence plant communities. We investigate how multiple environmental drivers affect community trait responses related to resource acquisition (plant height, specific leaf area (SLA), woodiness, and mycorrhizal status) and regeneration (seed mass, lateral spread) of European temperate deciduous forest understoreys. We sampled understorey communities and derived trait responses across spatial gradients of global-change drivers (temperature, precipitation, nitrogen deposition, and past land use), while integrating in-situ plot measurements on resources and conditions (soil type, Olsen phosphorus (P), Ellenberg soil moisture, light, litter mass, and litter quality). Among the global-change drivers, mean annual temperature strongly influenced traits related to resource acquisition. Higher temperatures were associated with taller understoreys producing leaves with lower SLA, and a higher proportional cover of woody and obligate mycorrhizal (OM) species. Communities in plots with higher Ellenberg soil moisture content had smaller seeds and lower proportional cover of woody and OM species. Finally, plots with thicker litter layers hosted taller understoreys with larger seeds and a higher proportional cover of OM species. Our findings suggest potential community shifts in temperate forest understoreys with global warming, and highlight the importance of local resources and conditions as well as global-change drivers for community trait variation.

Patterns of telephone use among nursing home residents.

There is convincing evidence that nursing home residents who have more visitors fare better than those who have fewer visitors. However, as many as one third of all individuals living in nursing homes have virtually no visitors. The purpose of this study was to address this concern by examining telephone use in older adults living in nursing homes, and evaluating the potential of telephone communications as a means of social support for this at-risk group. Using a recording device activated each time the receiver was picked up, the research team "listened in" on the telephone conversations of three nursing home residents (aged 76, 79, and 92) for a period of 1 week. The transcripts revealed 56 minutes of actual conversation during the week (10, 21, and 25 minutes, respectively), most often with family or longtime friends living out of town. Each resident laughed aloud more than once per minute. The telephone conversations provided the residents with vivid glimpses of life outside the walls of their facility and appeared to help them stay connected with their family and friends. The findings support further study of the telephone as a way to sustain authentic social support in long-term care populations.

Cerebral sinovenous thrombosis in the idiopathic hypereosinophilic syndrome in childhood.

The idiopathic hypereosinophilic syndrome (HES) is a leukoproliferative disorder marked by a sustained overproduction of eosinophils and a distinct predilection to damage specific organs, especially the cardiovascular system. It is primarily a disease of middle-aged people. Occasional cases have been encountered in children. We report a case of an 11-year-old boy affected by idiopathic HES with an unusual rapidly fatal course. In addition to eosinophilic cellulitis, cerebral straight and superior sagittal sinus vein thrombosis (CVT) was evident on cranial CT. In our review of the English literature we were unable to find an association between idiopathic HES and CVT.

Ultrasound characteristics of breast carcinoma.

Recent advances in ultrasound technology, such as the use of high-frequency linear transducers, color flow Doppler, and computer-enhanced imaging, have improved the diagnostic utility of ultrasound. The following retrospective study was performed to evaluate the efficacy of sonographic signs of malignancy and to compare sonography to mammography in 157 patients with palpable, biopsy-proven breast carcinomas. The mammogram reports and sonograms were all reviewed. The grade of each mammogram was recorded using the American College of Radiology mammogram grading scale. All sonograms were reviewed and assigned a score using an adaptation of this scale. Of 157 lesions, 121 were read as suspicious or probable malignancies on mammogram. Thirty-three lesions were read as benign or normal on mammogram. Three patients did not receive mammograms. All 157 lesions were read as either suspicious or probably malignant on ultrasound. Using the 16 described criteria, high-definition sonography complements mammography and appears to be a sensitive modality in the evaluation of palpable biopsy-proven breast malignancies. The diagnostic utility of ultrasound will likely be most important in the evaluation of nonpalpable breast masses; however, a prospective randomized trial will need to be performed.

Glaucoma care and conformance with preferred practice patterns. Examination of the private, community-based ophthalmologist.

BACKGROUND: Practice guidelines are becoming more prominent in the provision of medical care. A previous study demonstrated a high rate of conformance with recommended patterns of care for patients with open-angle glaucoma in an academic, public clinic setting. This study seeks to examine conformance within the private, community-based setting in which the vast majority of healthcare is delivered. METHODS: One-hundred ninety-three charts (average, 24 charts each from 8 different practices) of patients who received diagnoses for at least 2 years of open-angle glaucoma were evaluated retrospectively for conformance with recommendations from the American Academy of Ophthalmology's Preferred Practice Pattern (PPP) for primary open-angle glaucoma. The criteria were evaluated in three areas: (1) the performance of specified examination steps at the initial visit; (2) the performance of specified examination steps at follow-up; and (3) the time interval between follow-up visits. RESULTS: In 56.4% of patients who had stable moderate to severe glaucomatous damage, documentation of examination findings on the initial visit ranged from 39.4% for a pupil examination to 100% for intraocular pressure. At the initial visit, visual fields were obtained or scheduled in 90.2% of eyes, gonioscopy was performed in 51.3%, and the disc/nerve fiber layer status was noted in 97.9%. On follow-up, 44% of patients had documentation concerning the status of their glaucoma, but only 23.3% of patients had an optic nerve head drawing or photograph within 15 months of the most recent visit. In addition, the authors found that 37.8% of patient charts had neither an optic nerve head drawing nor a photograph documented after the initial visit. Finally, although 92.2% of patients with glaucoma were scheduled for follow-up within the time intervals recommended by the PPP, patients with uncontrolled or unstable glaucoma were the least likely to be followed up within PPP-recommended time intervals. CONCLUSIONS: Chart reviews from private, community-based ophthalmologists show that some initial examination steps such as gonioscopy and pupil examination are performed to widely varying degrees. While patients are generally likely to be scheduled for follow-up within PPP-recommended intervals, patients with unstable glaucoma are the least likely to be so scheduled. In addition, the visual appearance of the optic nerve is recorded for a relatively low percentage of patients. Additional data are needed from other geographic areas and other practice settings and for other patterns of care to more fully assess provider behavior relative to PPPs.

Ablation rates and surface ultrastructure of 193 nm excimer laser keratectomies.

PURPOSE: To determine whether photorefractive keratectomy can be performed at lower energies than are currently employed in clinical trials. METHODS: Fresh pig corneas were ablated using a clinical excimer laser to study the effects of various energy densities (100-200 mJ/cm2) and beam diameters on ablation rates and on the surface ultrastructure of the ablated cornea. RESULTS: A 20-mJ increase in energy density was associated with a 0.03 micron per pulse increase in the ablation rate. A nearly linear increase in the pseudomembrane thickness occurred with increasing energy densities (r2 = 0.83) or decreasing ablation area diameter (r2 = 0.86). CONCLUSIONS: Our findings suggest that fluences less than those currently used in clinical trials (160-180 mJ) are capable of ablating tissue while producing thinner electron-dense pseudomembranes on the corneal surface. The relationship between pseudomembrane thickness and clinical factors such as reepithelialization and postoperative haze remains to be determined. Operating at lower fluences does have the advantages of allowing larger diameter ablations, reducing possible shockwave damage, and reducing the maintenance requirements for the laser.

[Photorefractive keratectomy for correction of myopic astigmatism]. / Photorefraktive Keratektomie zur Korrektur von myopem Astigmatismus.

Nine eyes underwent superficial ablation with excimer laser for treatment of compound myopic astigmatism. In eight of the eyes, corneal cylinder was naturally-occurring, and in one eye the astigmatism had developed following retinal detachment surgery. All patients have been followed for 9 months. The pre- and postoperative cylinder was -2.7 +/- 0.4 diopters and -1.3 +/- 0.4 diopters, respectively, while the pre- and postoperative spherical equivalent was -4.7 +/- 0.4 diopters and -1.3 +/- 0.4 diopters, respectively. Uncorrected acuity improved from a preoperative mean of 20/300 to a postoperative mean of 20/40. Patients with a residual refractive error often demonstrated reasonably good unaided acuity. Toric ablations with the excimer laser can be performed at the same time as ablations for myopia, and appear to represent a promising strategy for correction of compound myopic astigmatism; the relative safety and efficacy of this procedure, and of combined radial and astigmatic keratotomy remain to be determined.

Photorefractive keratectomy for severe postkeratoplasty astigmatism.

We performed cylindric corneal ablations with the excimer laser on 12 patients to correct severe, disabling astigmatism after keratoplasty. In some patients, an additional ablation was performed to correct myopia. Patients were followed up for an average of eight months (range, six to 14 months). Uncorrected visual acuity improved in nine patients, and nine of the 12 patients had a decrease in refractive cylinder at last follow-up. The mean preoperative refractive cylinder was 7.0 +/- 3.6 diopters, which decreased to a mean of 3.1 +/- 2.6 diopters at one month (P = .0003) and 4.3 +/- 2.9 diopters at last follow-up (P = .03). Keratometric astigmatism decreased from 7.5 +/- 3.9 diopters preoperatively to 5.2 +/- 3.9 diopters at the last follow-up (P = .001). Mean spherical equivalent was reduced from -7.4 +/- 4.2 diopters preoperatively to -3.3 +/- 4.4 diopters postoperatively (P = .003). Postoperative corneal haze, when present, did not reduce visual acuity. Excimer laser superficial keratectomy thus appears to be safe when used for postkeratoplasty ametropia, although substantial regression may limit its effectiveness in some patients.

Corneal surface after deepithelialization using a sharp and a dull instrument.

Manual removal of the corneal epithelium currently precedes excimer laser photorefractive keratectomy. To assess the smoothness of the corneal surface following this procedure, six paired human eye-bank eyes (12 eyes) were manually deepithelialized using a blunt instrument (Paton spatula) on one eye and a sharp instrument (surgical blade) on the contralateral eye; all deepithelializations were done by the same surgeon. The 12 corneas were then resected and processed in an identical fashion for scanning electron microscopy. The microphotographs obtained showed that among the corneas deepithelialized with the blunt spatula, two had a smooth surface, and four had variable amounts of residual epithelial cells and basement membrane, confirmed by light microscopy. The surface of five corneas deepithelialized with the sharp instrument were slightly rougher than the former, with occasional linear scratches; one cornea retained a small amount of basement membrane. Removal of epithelium appears to be more complete when a sharp instrument is used. These findings may have clinical relevance, since residual epithelium and basement membrane after deepithelialization may influence the depth of ablation subsequently achieved with the excimer laser.

Corneal sensitivity after photorefractive keratectomy.

Corneal anesthesia or hypesthesia can complicate refractive surgical procedures such as epikeratophakia and radial keratotomy. An esthesiometer was used to measure the corneal sensitivity in unoperated-on corneas and fellow corneas after excimer laser photorefractive keratectomy. Decrease in corneal sensitivity was noted within six postoperative weeks, with mean sensitivity being 75.2% +/- 13.3% of normal. Within the first three postoperative months, the patients operated on for correction of compound astigmatism recovered 95.7% +/- 5.3% of the corneal sensitivity, whereas the patients operated on for correction of severe myopia recovered 86.2% +/- 11.2% (P = .07). None of the patients had delayed epithelial healing or recurrent corneal erosions during the time of decreased corneal sensitivity. In otherwise normal myopic eyes, photorefractive keratectomy measurably reduced corneal sensitivity for several postoperative weeks.