Morphology of age-related cuneiform cortical cataracts: the case for mechanical stress

We evaluated the gross morphology, location, and fiber cell architecture of equatorial cortical opacities in the aging human lens. Using dark-field stereomicroscopy, we photographed donor lenses in toto and as thick slices. In addition, we investigated the details of the fiber cell architecture using fluorescent staining for membranes and by scanning electron microscopy. We then combined our data with data from recent studies on lens viscoelasticity. We found that small cortical and cuneiform opacities are accompanied by changes in fiber structure and architecture mainly in the equatorial border zone between the lens nucleus and cortex. Because the lens cortex and nucleus have different viscoelastic properties in young and old lenses, we hypothesize that external forces during accommodation cause shear stress predominantly in this border zone. The location of the described changes suggests that these mechanical forces may cause fiber disorganization, small cortical opacities, and ultimately, cuneiform cataracts.

Straylight effects with aging and lens extraction

PURPOSE

To assess possible gains and losses in straylight values among the population to consider straylight as added benefit of lens extraction.

DESIGN

In this cross-sectional design, data from a multicenter study on visual function in automobile drivers were analyzed.

METHODS

On both eyes of 2,422 subjects, visual acuity (logarithm of the minimum angle of resolution [logMAR] in steps of 0.02 log units), straylight on the retina (psychophysical compensation comparison method), and lens opacity (slit-lamp scoring using the Lens Opacities Classification System III [LOCS III] system) were determined. Three groups were defined: 220 pseudophakic eyes, 3,182 noncataractous eyes (average LOCS III score, <1.5), and 134 cataractous eyes (average LOCS III score, >3.0).

RESULTS

Noncataractous straylight values increases strongly with age as: log(s) = constant + log(1 + (age / 65)(4)), doubling by the age of 65 years, and tripling by the age of 77 years. Population standard deviation around this age norm was approximately 0.10 log units. The cataract eyes (in this active driver group) had relatively mild straylight increase. In pseudophakia, straylight values may be very good, better even than in the noncataract group. Visual acuity and straylight were found to vary quite independently.

CONCLUSIONS

Lens extraction holds promise not only to improve on the condition of the cataract eye, but also to improve on the age-normal eye. Lens extraction potentially reverses the strong age increase in straylight value, quite independently from visual acuity.

Human lens capsule thickness as a function of age and location along the sagittal lens perimeter

PURPOSE

To investigate the variation in the thickness of the human lens capsule along the lens perimeter, as well as its changes with age.

METHODS

Altogether, 26 human donor lenses, aged 12 to 103 years, were histologically processed. Sagittal sections were stained for collagen with periodic acid-Schiff (PAS). Serial images of the lens border were taken with a photomicroscope and 25x objective. Capsular thickness was measured every 250 microm along the entire lens perimeter.

RESULTS

All studied capsules were thicker anteriorly, continuously increasing with age from 11 to 15 microm in average at the anterior lens pole. Maximum thickness was located at the anterior midperiphery, increasing with age from 13.5 to 16 microm. In most cases, there was a local thinning at a pre-equatorial zone, recovering to approximately 7 microm at the equator. The latter value, as well as the minimal thickness at the posterior pole (mean 3.5 microm), did not change with age, whereas the average thickness at the posterior periphery decreased from 9 to 4 microm.

CONCLUSIONS

The human lens capsule thickness is at its maximum at the anterior midperiphery, which appears to be located central to the zonular insertion. It increases with age, especially at the anterior pole, while the midperipheral zone stabilizes or slightly decreases after the seventh decade. The anterior zonular insertion is actually related to a local pre-equatorial thinning, which remains unchanged with age. There was no posterior peripheral thickening, except in a few younger patients, with a modest relative maximum roughly at the equator. From here, the posterior capsule becomes progressively thinner and also diminishes with age, except for the thinnest, but stable posterior pole.

Successful Treatment of Sexual Disinhibition in Dementia with Carbamazepine

Sexual disinhibition is a disturbing behavioral symptom in dementia. At present, there are no treatment guidelines available. Here we present the successful use of carbamazepine in a 78-year old AD patient with hypersexual behavior. The efficacy of carbamazepine in this case is in parallels to its effects on aggression and agitation in dementia and supports the important role of anticonvulsants in the management of behavioral disturbances in demented patients.

Work-related trauma: the experiences of perioperative nurses

Traumatic experiences in the workplace are an integral part of the role of the perioperative nurse. The atypical nature and characteristics of these experiences is such that perioperative nurses may suddenly encounter reactions and feelings that are very different and more intense than anything they will have encountered previously. Furthermore, these events may increase the risk of them experiencing subsequent trauma stress reactions and place them at risk of profound distress and significantly impaired functioning. A survey of 233 nurses working in rural and metropolitan operating theatres assessed the range and types of traumatic work experiences. Results showed that exposure to traumatic events was reported by 161 (69%) of all respondents and a wide range of traumatic experiences were reported to have affected their well-being. The findings have implications for the formulation of trauma management strategies, both at individual and organisational levels and suggest new directions for education and research in promoting a recovery environment in which perioperative nurses can work.

Estimation of safe exposure time from an ophthalmic operating microscope with regard to ultraviolet radiation and blue-light hazards to the eye

Hazards from the optical radiation of an operating microscope that cause damage at the corneal, lenticular, and retinal levels were investigated; we considered, in particular, ultraviolet radiation (UVR) and blue light. The spectral irradiance from a Zeiss operation microscope OPMI VISU 200 was measured in the corneal plane between 300 and 1100 nm. Effective irradiance and radiance were calculated with relative spectral effectiveness data from the American Conference for Governmental and Industrial Hygienists. Safe exposure time to avoid UVR injury to the lens and cornea was found to be 2 h without a filter, 4 h with a UVR filter, 200 a yellow filter, and 400 h with a filter combination. Safe exposure time to avoid retinal photochemical injury was found to be 3 min without a filter and with a UVR filter, 10 min with a yellow filter, and 49 min with a filter combination. The effective radiance limit for retinal thermal injury was not exceeded. The hazard due to the UVR component from the operating microscope is not critical, and operation time can be safely prolonged with the use of appropriate filters. The retinal photochemical hazard appears critical without appropriate filters, permitting only some minutes of safe exposure time. The calculated safe exposure times are for worst-case conditions and maximal light output and include a safety factor.

EFFECT OF ACUTE BRAIN DEATH ON RELEASE OF ATRIUM AND B-TYPE NATRIURETIC PEPTIDES IN AN ANIMAL MODEL

INTRODUCTION

Atrium and B-type natriuretic peptides (ANP and BNP) and big endothelin (ET)-1 are markers for severity of heart failure and may be used in the quality assessment of donor hearts. Elevated cardiac troponins predict early graft failure after heart transplantation. This study evaluated the effects of acute brain death (BD) on the release of ANP, BNP, big ET-1, and cardiac troponins in an animal model.

MATERIALS AND METHODS

Pigs were randomized into a BD group (n=5) and a control group (n=5). In the first group, acute BD was induced, and anesthesia was stopped. In the control animals, a sham operation was performed, and anesthesia was continued. Parameters were measured at baseline and for 13 hours postoperatively.

RESULTS

After acute BD, there were significant hemodynamic changes. In the control group, the BNP level was higher than in the BD group and decreased over time (P =0.016). There was no significant change in BNP release in the BD group up to 13 hours (P =0.1). ANP release remained stable over time in the control group (P =0.35) but decreased in the BD group (P =0.043). The big ET-1 levels were not different between groups. Cardiac troponin I was elevated in the BD group 5 hours after BD (P< 0.05) but remained under 1.5 mg/L throughout the study.

CONCLUSION

Acute BD did not lead to an increase of BNP and ANP levels. Moreover, intact brain function seems to augment the release of natriuretic peptides from the myocardium. Further clinical evaluation of prognostic values of natriuretic peptides for the assessment of donor hearts is necessary. Cardiac troponins are a useful additional tool in the evaluation of donor hearts.

Changes in the refractive index of lens fibre membranes during maturation--impact on lens transparency

PURPOSE

Local variations in refractive index are the physical cause of light scattering in a material or tissue and also induce phase changes of propagating light waves. The goal of this study was to analyse local differences in refractive index by phase contrast microscopy of sections of human lenses.

METHODS

Refractive index was estimated by immersion refractometry. Cryo-sections of quick-frozen human donor lenses were embedded in a graded series of bovine serum albumin solutions, and in immersion oil, ranging in refractive index from 1.34 to 1.52.

RESULTS

Fibre membranes in the lens cortex prove to have a refractive index considerably above that of fibre cytoplasm at the same location. Fibre membranes in the lens nucleus have a refractive index approximately the same as that of fibre cytoplasm at the same location.

CONCLUSION

In the lens cortex, transparency is obtained by a high spatial order of the lens fibre lattice to compensate for the light scattering caused by differences in refractive index between fibre membranes and cytoplasm. In the lens nucleus, high spatial order is less important, because the minor differences in the refractive index between fibre membranes and fibre cytoplasm lead only to minimal scattering.

Impact of age and sex in ultraviolet radiation cataract in the rat

PURPOSE

The purpose of this study was to determine the influence of age and sex on the development of ultraviolet radiation (UVR) cataract in rats. Current safety limits for lens damage due to UVR do not consider age or sex.

METHODS

Four age groups of Sprague-Dawley rats (3, 6, 17, and 52 weeks) were exposed to 300-nm UVR at either 5 or 8 kJ/m(2), delivered during 15 minutes. The interval between irradiation and cataract assessment was 1 or 8 weeks. Moreover, two groups of 6-week-old male and female rats were exposed to 5 kJ/m(2) UVR, with cataract assessment after 1 week. The severity of cataract was quantified by measurement of forward light-scattering in isolated lenses.

RESULTS

The youngest age group showed development of anterior subcapsular, equatorial, and nuclear cataract, whereas the three older groups exhibited the first two types. The two younger age groups had significantly more cataract than the other groups. The degree of cataract increased from 1 to 8 weeks after irradiation. There was no difference in cataract severity between sexes.

CONCLUSIONS

Young rats are more sensitive to UVR than old rats. Nuclear UVR cataract develops in young rats but not in adult rats. With the chosen waveband and dose, the time for maximum cataract development to occur is longer than 1 week. There is no difference in UVR sensitivity between the sexes.

Maximum acceptable dose of ultraviolet radiation: a safety limit for cataract

PURPOSE

To develop a method for experimental estimation of toxicity for continuous dose-response relationships. To apply this method to cataract induced by ultraviolet radiation (UVR) in young rats.

METHODS

After establishing experimentally the frequency distribution of light scattering of normal physiologically clear lenses, the lower limit of pathological light scattering is defined such that a certain fraction, for example 97.5%, of normal lenses scatter less light.

RESULTS

The dose-response function for UVR and cataract is determined experimentally. With this function, the dose corresponding to the lower limit of pathological light scattering may be determined as the maximum acceptable dose (MAD). The MAD0.975 for UVR 300 nm was determined to be 2.2 kJ/m2.

CONCLUSIONS

The method can serve as a basis for establishing safety standards for UVR-induced cataract and probably other continuous dose-response functions.

Uvulopalatopharyngoplasty for sleep apnea in mentally retarded obese 14-year-old: an anaesthetic challenge

Anaesthetic management of patients with obstructive sleep apnea for upper airway surgery has always been a challenging task. We report our anaesthetic approach for a young, mentally retarded obese patient with documented obstructive sleep apnea undergoing uvulopalatopharyngoplasty. The therapeutic intervention before, during and after operation is discussed.

Epidural buprenorphine in management of pain in multiple rib fractures

BACKGROUND

Pain from multiple rib fractures may affect pulmonary function, morbidity, and length of stay in the intensive care units. This study describes some clinical characteristics of epidural buprenorphine, a lipophilic and partial opiate agonist with a higher micro receptor affinity than morphine, in combating the pain in multiple rib fractures.

METHODS

The study was conducted prospectively over a 15-month period. A total of 27 patients admitted to the hospital with multiple rib fractures were studied. Buprenorphine at a concentration of 0.3 mg in 5-10 ml normal saline was administered epidurally, twice daily the first 24 h, thereafter once daily. Ventilatory function tests (including vital capacity, tidal volume, respiratory rate, and minute volume) and assessment of pain intensity using a simple, categorical, verbal rating scale were obtained before and after institution of analgesia. Any nausea, vomiting, hypotension, urinary retention, respiratory depression or pruritus were recorded.

RESULTS

We found a significant improvement in ventilatory function tests during the 1st, 2nd, and 3rd day after epidural analgesia when compared with the preanalgesia levels (P < 0.001). Changes in the verbal rating scale demonstrated that epidural buprenorphine was associated with marked improvement in pain at rest and pain during coughing and deep breathing. None of our patients developed hypotension (<10% of the baseline), urinary retention or respiratory depression. Nausea, vomiting, and mild pruritus were the only reported complications.

CONCLUSIONS

Epidurally introduced narcotic, like buprenorphine in saline, has been found to be effective in our study to achieve adequate analgesia in treatment of patients with multiple rib fractures. In addition, this methodology of pain relief eliminates the costly delivery system and early discharge, and allows walking epidurals and follow-up on outpatient basis.

Loss of bone mass and vitamin D deficiency after hematopoietic stem cell transplantation: standard prophylactic measures fail to prevent osteoporosis

Bone mineral density (BMD) and biochemical markers of bone metabolism were analyzed in 67 adults with ALL (n = 27), AML (n = 14), MDS (n = 6) and CML (n = 20) before and after allogeneic stem cell transplantation (SCT). Median age was 36 years (17-56). Twenty-six out of 53 patients (49%) had osteopenia and osteoporosis before SCT, 21/26 had acute leukemias and 5/26 had chronic myeloid leukemia (CML). T-score before SCTwas -1.23 in patients with acute leukemias and 0.62 in CML patients (P = 0.001). After SCT, a significant loss of BMD was observed in all patients. After 6 months, 24 of 36 evaluable patients (67%) had pathologic BMD, 11 of them (30%) had developed osteoporosis. After 12 months, 20 of 32 evaluable patients (62%) had BMD values below normal and nine of them (28%) had osteoporosis. Increased pyridinium excretion was observed in 12/20 patients (60%) with acute leukemias, but only in 3/13 (23%) with CML (P = 0.014). A prolonged vitamin D deficiency for more than 6 months developed early after SCT in all patients. Patients with acute leukemias frequently have osteopenia and osteoporosis before SCT. After SCT, a further loss of BMD occurs independent from the underlying disease. Standard prophylactic measures are not sufficient to prevent loss of bone mass. Studies on prophylactic interventions are needed to prevent severe osteoporosis in long-term survivors of SCT.

Continuous thoracic epidural anesthesia with 0.2% ropivacaine versus general anesthesia for perioperative management of modified radical mastectomy

We evaluated in this prospective study the effectiveness of continuous thoracic epidural anesthesia (TEA) and postoperative analgesia with ropivacaine and compared it with general anesthesia (GA) and opioids for pain relief, side effects, postanesthesia recovery, and hospital discharge after modified radical mastectomy. Sixty ASA physical status II and III patients undergoing mastectomy were randomly assigned to two study groups of 30 patients each. In the TEA group, an epidural catheter was inserted at T6-7, and 5--10 mL of 0.2% ropivacaine was injected to maintain anesthesia and to continuously administer adequate analgesia for 48 h. GA was induced with IV 1--2 mg of midazolam or 50--100 microg/mL of fentanyl followed by 50--150 mg of propofol and was maintained with sevoflurane and 50% N(2)O in oxygen. The Aldrete score system was used to evaluate postanesthesia recovery, a verbal rating scale was used for assessment of pain intensity, and a postanesthesia discharge scoring system was used for discharge home. The demographic data and side effects (except for nausea and vomiting) (GA 43%, TEA 10%, P = 0.0074) and discharge home were similar in both groups. However, the number of patients ready for discharge from the recovery room during the first postanesthesia hour (Aldrete score of 10) was significantly larger after TEA (80%) than after GA (33%) (P = 0.0006). GA patients experienced significantly more (P < 0.001) substantial pain than TEA patients on Day 0 (70%), Day 1 (53%), and Day 2 (27%) after the surgery. Patient satisfaction was greater with TEA (70%) than with GA (30%) (P < 0.001). We conclude that TEA with ropivacaine provides better postoperative pain relief and less nausea and vomiting, facilitates postanesthesia recovery, and gives greater patient satisfaction than GA.

Lens growth and protein density in the rat lens after in vivo exposure to ultraviolet radiation

PURPOSE

To investigate lens growth after different doses of ultraviolet radiation (UVR) and to investigate the long-term effect of a near-threshold UVR dose on the refractive index distribution in the lens.

METHODS

Sprague-Dawley rats received UVR (lambda(MAX) = 300 nm) unilaterally during a 15-minute period. The exposure dose ranged from 0.1 to 20 kJ/m(2), and the rats were kept for up to 32 weeks after exposure. Intact lenses were photographed and lens wet and dry masses were measured. The protein density was estimated by quantitative microradiography. Freeze-dried lens sections were used for contact x-ray photographs. From the transmission of the microradiographs, protein density and refractive index profiles were calculated along the lens radius with a resolution of 2.5 microm.

RESULTS

Lens dry mass in exposed eyes was lower than in nonexposed eyes at one week after exposure. Lens water content was decreased after low UVR doses but increased after high doses. The difference between exposed and nonexposed lenses in dry mass and water content increased with time after exposure. No significant difference was found for the mean protein density in exposed and nonexposed lenses. The protein density increased linearly in the lens cortex, from a minimum in the superficial cortex of 0.26 g/cm(3) to a maximum in the deep cortex of 0.81 g/cm(3). This corresponded to a refractive index of 1.38 and 1.48, respectively.

CONCLUSIONS

Lenses exposed to UVR grew more slowly than their nonexposed contralaterals. This growth inhibition was dose dependent. Near-threshold doses led to decreased water content in the lens whereas high doses led to swelling. Six months after near-threshold UVR exposure, no global change of the refractive index was found. However, local variations of the refractive index caused a subtle cortical light scattering.