A light-weight cooling vest enhances performance of athletes in the heat.

During the 1990s, emphasis on the health and safety of people who exercise in hot, humid conditions increased and many organizations became aware of the need for protection against heat-related disorders. A practical, pre-cooling strategy applicable to several sporting codes, which is low cost, easy to use, light-weight and which enhances cooling of the human body prior to and following exercise, was developed and tested. Eight males and eight females participated in a maximal oxygen consumption (VO2max) test and four trials: a control (without cooling) and wearing each of three different cooling vests (A, B, C). Vests were worn during the rest, stretch, warm-up (50% VO2max) and recovery stages of the protocol, but not during the 30 min run (70% VO2max). Core and skin temperatures during exercise were reduced (by approximately 0.5 degrees C, rectal; 0.1-1.4 degrees C, abdominal skin temperature) and sweat rates were lower (by approximately 10-23%). Endurance times for running at 95% of VO2max were increased by up to 49 s. Perceptions of the thermal state and skin wetness showed changes to greater levels of satisfaction. Physiological and sensory responses were related to design features of the vests.

Aniridia and optic nerve hypoplasia.

BACKGROUND: This study evaluates, in patients with aniridia, the prevalence of optic nerve hypoplasia and its association with foveal hypoplasia. METHODS: The medical records of 56 patients with aniridia (31 female, 25 male, mean age 33 years, range 2-74 years) were retrospectively evaluated for optic nerve and foveal hypoplasia. The difference in prevalence of foveal hypoplasia in patients with and without optic nerve hypoplasia was compared using Fisher's exact test. RESULTS: Six of 56 patients, 10.7% (95% CI: 4.8-21.5%), had optic nerve hypoplasia; hypoplasia was found in both eyes of five binocular patients and in one monocular patient. The prevalence of foveal hypoplasia was higher in aniridia patients with optic nerve hypoplasia than in those without (50.0 vs 6.0%); this difference did not achieve statistical significance (P=0.10). CONCLUSIONS: Clinically apparent optic nerve hypoplasia is found in roughly 10% of patients with aniridia and may occur independently or in association with foveal hypoplasia.

Helmet design to facilitate thermoneutrality during forest harvesting.

The purpose of this investigation was to evaluate the ventilatory characteristics of vented and non-vented helmets for use in forestry harvesting operations. A ventilation index developed by Birnbaum and Crockford (1978) was used to determine the ventilation capacity of twelve helmets varying in design and presence, location, and dimension of vents. Helmets with top vents had higher ventilation indices than non-vented, side and side/top-vented helmets. Ten physically fit men participated in a maximal oxygen consumption test and four trials wearing a non-vented, round-side-vented, round-top-vented or rectangulartop-vented helmet. Trials simulated typical summer environmental conditions (28 degrees C, 80% rh) and physiological work loads (40% VO(2)max) experienced during forest harvesting in New Zealand. The temperature and humidity under the helmet was typically lowest when the helmet with the largest vented area (288 mm(2)) in the crown was worn, although physiological responses (temperatures at the tympanum, ear and scalp; humidity at the centre of the helmet) of the participants to wearing the helmets differed significantly during some rest periods only. Top-vented helmets (in this experiment measured 288 mm(2)) should be worn to minimize temperature and humidity of the head during forest harvesting operations.

Oral acyclovir for the management of herpes simplex virus keratitis in children.

PURPOSE: To evaluate the use of oral acyclovir in pediatric patients with herpes simplex virus (HSV) keratitis. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Seven pediatric patients seen at the University of Minnesota Hospitals and Clinics with herpes simplex virus (HSV) infectious epithelial keratitis between January 1992 and October 1998. Patient ages ranged from 6 weeks to 5 years at time of presentation with a median of 1.7 and mean of 1.9 years. INTERVENTION: All patients received oral acyclovir; six of seven patients also received topical antiviral medications. Three of seven patients had topical antiviral therapy fail before being placed on oral acyclovir, and the remaining four patients were placed on oral acyclovir primarily. RESULTS: All patients showed resolution of HSV infectious epithelial keratitis. Three patients have been maintained on prophylactic dosage of oral acyclovir because of recurrent disease or because they have been chronically treated with topical corticosteroids for immune stromal keratitis. All patients tolerated acyclovir well, and there were no adverse reactions. CONCLUSIONS: Oral acyclovir is useful in treating HSV infectious epithelial keratitis in pediatric patients. It is beneficial in treating infectious epithelial keratitis and prophylactically either while treating with topical corticosteroids for immune stromal keratitis or for preventing recurrent infectious epithelial keratitis.

Development of sizing systems for protective clothing for the adult male.

The aim of the study was to obtain comprehensive anthropometric data from which to develop a sizing system appropriate for inclusion in specifications for protective clothing; and for purchases of other selected equipment. Fifty-five body dimensions on a male sample of the New Zealand Fire Services (n = 691, approximately 7% of employees) were obtained by direct measurement. Descriptive statistics and selected percentiles (5th, 50th, 95th) are given. The body dimensions accounting for most of the variance in the data were established by factor analysis and are reported here. Size groups for various body sections based on the relevant measurements of that section were established by cluster analysis around a control variable.

Conjunctival epithelial cells cultured on human amniotic membrane fail to transdifferentiate into corneal epithelial-type cells.

PURPOSE: Previous studies on the use of human amniotic membrane (HAM) in rabbit stem cell deficiency models have found the new epithelium growing over the HAM to express cornea-specific keratins (K3 and K12) in 40% of the cases, suggesting that HAM may have induced conjunctival epithelial cells to transdifferentiate into cornea-type epithelial cells. The current study was performed to determine whether HAM could induce transdifferentiation of conjunctival epithelia] cells when cultured in vitro. METHODS: Conjunctival grafts taken from the fornices of New Zealand white rabbits (6-12 weeks old) were placed over HAMs and lifted to an air-media interface using polypropylene double rings. These cultures were maintained in supplemented hormonal epithelial medium with and without 3T3 feeder cells. Rabbit corneal epithelial cells were cultured similarly using strips of keratolimbal grafts placed over HAM. The cultures were terminated at various times between the 8th and 15th day. The cultured epithelial cells were examined histologically and immunohistochemically using monoclonal antibodies AK-2 (to K12 keratin), AM-3 (to goblet cell mucin), and AE-5 (to K3 keratin). RESULTS: Both conjunctival and corneal epithelial cells cultured on HAMs showed multilayered, differentiated epithelial structures. On immunohistochemical examination, both epithelial cells stained positive for AE-5. None of the cultured conjunctival epithelial cells stained positively for AK-2, while the corneal epithelial cells showed positive staining with AK-2. There were no AM-3-positive goblet cells in either epithelial cell culture. There was no difference in the immunohistochemical patterns between cultures with or without 3T3 feeder cells. However, culture without feeder cells seemed to manifest a more degenerative appearance than those with feeders. CONCLUSION: HAM does not induce transdifferentiation of conjunctival epithelial cells into corneal-type epithelial cells under the in vitro culture conditions used in this study.

Classification of herpes simplex virus keratitis.

PURPOSE: We propose a nomenclature for classification of herpes simplex virus (HSV) keratitis. We hope that a more consistent classification system will lead to a better understanding of the disease processes, thus resulting in improved diagnosis, treatment, and patient outcomes. METHODS: A review of the literature was performed to evaluate current HSV classification systems. These systems were evaluated in the context of both current clinical and basic science studies and our own clinical observations. RESULTS: The proposed classification system is based on the anatomy and pathophysiology of the specific presentations of HSV keratitis. Anatomically, the primary level of corneal involvement, whether epithelium, stroma, or endothelium, must be elucidated. Pathophysiologically, the cause of the inflammation. whether immunologic, infectious, or neurotrophic, must be determined. There are four major categories of HSV keratitis. (1) Infectious epithelial keratitis, which is made up of cornea vesicles, dendritic ulcer, geographic ulcer, and marginal ulcer. (2) Neurotrophic keratopathy, which includes punctate epithelial erosions and neurotrophic ulcer. (3) Stromal keratitis, which is subdivided into necrotizing stromal keratitis and immune stromal keratitis. (4) Endotheliitis, which has three clinical presentations: disciform, diffuse, and linear. CONCLUSION: We believe that by categorizing cases of HSV keratitis by their primary anatomic and pathophysiologic etiologic characteristics, clinicians can better understand and therefore treat all types of HSV keratitis. The four main categories of HSV keratitis are infectious epithelial keratitis, neurotrophic keratopathy, stromal keratitis, and endotheliitis. Each of these is subdivided to more specific clinical presentations.

Ex vivo transduction of corneal epithelial progenitor cells using a retroviral vector.

PURPOSE: To transduce corneal epithelial progenitor cells with a reporter gene using a retroviral vector and follow their progeny in vitro and in vivo. METHODS: Using a lacZ-producing retroviral vector, rabbit keratolimbal explants were transduced ex vivo, autografted onto their original sites, and assessed for lacZ-producing cells in the cornea throughout a 6-month period. Four autografts served as control samples, having received no vector. Experimental and control rabbits were euthanized and corneas with scleral rims harvested, weekly for 4 weeks and then monthly for 6 months. The corneas were first stained with 5-bromo-4-chloro-3-indolyl galactopyranoside (X-gal) as wholemounts and then sectioned for histology and immunohistochemistry to examine lacZ-positive cell outgrowth. Three additional transduced explants were observed in culture. These explants were transferred to new culture dishes every week for 9 weeks. The previously occupied culture dish was stained for lacZ to detect transduced epithelial cells, and the number of lacZ-positive cells was quantitated. RESULTS: LacZ-positive cells were found in the corneas of 18 of 20 eyes in which virally transduced keratolimbal autografts had been implanted. The cells were epithelial in nature, originated from the limbus, and were found in colonies throughout the epithelial layer of the cornea. The appearance of lacZ-positive cells in four of five corneas harvested after 6 months showed long-term transgene expression consistent with transduction of corneal epithelial stem cells. In vitro, the number of lacZ-positive cells migrating from the keratolimbal autografts decreased rapidly during the first 4 weeks and then remained stable through week 9. CONCLUSIONS: This study shows that a retroviral vector can effectively transduce corneal epithelial progenitor cells, shown by the long-term appearance of transduced cells on the cornea in vivo and the stable production of lacZ-positive cells in vitro. The appearance and disappearance of labeled cells is consistent with the initial transduction of stem cells and transient amplifying cells.

Keratolimbal allograft: recommendations for tissue procurement and preparation by eye banks, and standard surgical technique.

PURPOSE: To facilitate increased use of keratolimbal allograft transplantation (KLAL) for severe ocular surface disease (OSD) by informing clinicians and eye banks of differences in tissue requirements and preparation for the procedure and to describe the surgical technique of KLAL transplantation. METHODS: The protocol of the Minnesota Lions Eye Bank is described for procuring and preparing tissue for KLAL transplantation. The surgical technique is described in detail. RESULTS: Over the last several years, we have modified our eye-banking procedures as well as our surgical technique to improve the success of KLAL transplantation. CONCLUSION: KLAL transplantation for patients with severe ocular-surface disease is an important management option. Success is influenced by the ability to obtain appropriate tissue; this requires clinicians and eye banks to expand current procurement guidelines.

The association between ocular cicatricial pemphigoid and rheumatoid arthritis.

PURPOSE: To assess the pathogenesis, symptomatology, and severity of rheumatoid arthritis (RA) in patient's with concomitant ocular cicatricial pemphigoid (OCP). METHODS: We retrospectively analyzed the charts of eight patients seen at a single institution between the years 1972 and 1997 with concomitant RA and OCP. Patients with OCP secondary to medical therapy, radiation, or chemical burns, or Stevens-Johnson syndrome were excluded. RESULTS: The female-to-male ratio was 7:1. All patients had positive serum rheumatoid factors and immunohistochemical confirmation of OCP. The mean number of years of RA prior to OCP diagnosis was 19. The number of patients with stage II OCP was three of eight (37.5%). The number of patients with stage III OCP was five of eight (62.5%). All patients had radiologic evidence of degenerative joint disease and synovial thickening. All eight patients had keratoconjunctivitis sicca, five of eight patients (62.5%) had Sjögren's syndrome, and five of eight patients (62.5%) developed rheumatoid cornea necrosis leading to corneal perforation. CONCLUSIONS: The implication exists that RA and OCP may be linked via an immunologically mediated mechanism and that patients with severe extraarticular symptoms associated with RA may be more likely to develop OCP. Prompt recognition of overlying symptoms may facilitate proper therapy for control of both diseases.

Long-term results of transsclerally sutured posterior chamber lenses in penetrating keratoplasty.

PURPOSE: To evaluate the long-term safety and efficacy of transsclerally sutured posterior chamber lenses in penetrating keratoplasty. METHODS: This was a retrospective review of 130 patients who underwent penetrating keratoplasty and placement of a transsclerally sutured posterior chamber lens with at least 1 year of follow-up. The mean follow-up period was 38.8 months. There were 61 patients who had been followed for at least 3 years (mean, 59 months). RESULTS: At follow-up the visual acuity was 20/40 or better in 40 patients (31%) and 20/50 to 20/200 in 48 patients (36%). The primary reasons for decreased visual acuity were age-related macular degeneration (18%) and graft failure (13%). New-onset glaucoma was found in 19 of 82 patients (23%). In the 48 patients who had elevated intraocular pressures preoperatively, the pressure improved in 13 patients (27%) and worsened in 12 patients (25%). Exposure of the haptic suture through the conjunctiva occurred in 14 patients (11%) at an average of 12 months after surgery. Of these, seven (19%) occurred in patients with conjunctival flaps, and seven (16%) in patients who had scleral flaps covering the haptic suture. No erosions occurred in the cases in which the suture was rotated inside the eye. CONCLUSION: Improvements in the surgical technique have made transsclerally sutured posterior chamber lenses safer in patients with inadequate capsular support. The long-term visual results in penetrating keratoplasty are acceptable and comparable to those of other techniques.

In vivo confocal microscopic analysis of corneal allograft rejection in rabbits.

PURPOSE: To demonstrate in vivo confocal microscopic features of corneal allograft rejection that may be useful for differentiating graft rejection from other conditions. METHODS: Corneal donor buttons from Dutch Belted (DB) pigmented rabbits were transplanted orthotopically into New Zealand White (NZW) recipient corneal beds. Slit-lamp and confocal microscopic examinations were performed every 3 days thereafter until the time of graft failure. RESULTS: Allograft-rejection signs began to appear during the fourth postoperative week. In epithelial rejection, small inflammatory cells were visualized forming a linear rejection line mixed with larger damaged epithelial cells. Subepithelial infiltrates (SEIs) could be discerned as aggregates of small and highly refractile inflammatory cells within the extracellular matrix. An area of stromal rejection showed increased reflectivity of stromal edema with numerous small infiltrated inflammatory cells. Keratic precipitate (KP) was visualized to be protruding into the anterior chamber with surrounding normal polygonal endothelial cells at its base. Endothelial rejection lines were formed by cellular aggregates of small inflammatory cells and damaged larger endothelial cells with pyknotic highly reflective nuclei. With the progression of endothelial rejection, damaged endothelial cells decreased in number, increased in size, and extended pseudopod-like cytoplasmic structures. CONCLUSION: In vivo confocal microscopy can provide us with detailed histopathology of corneal graft rejection, which might be useful for differentiating immune rejection from other graft conditions and may provide a technique for early diagnosis of rejection before slit-lamp findings.

Etiology of immune stromal (interstitial) keratitis.

PURPOSE: We compared the etiologies of immune stromal keratitis (ISK), also known as interstitial keratitis (IK), in a recent group of patients with active and inactive ISK. METHODS: We reviewed the charts of 97 patients seen in the cornea clinic at the University of Minnesota from 1985 through 1994. Fifty-five patients were classified as having active ISK, defined by stromal inflammation without ulceration within 1 year of presentation. Forty-two patients were identified as having inactive ISK, defined by evidence of past stromal inflammation including stromal scarring, stromal thinning, ghost vessels, and reduplication of Descemet's membrane without active inflammation for the 1 year before presentation. We determined the etiology of the ISK by careful review of the patient's ocular examination, as well as medical and laboratory workup. Patients were labeled with the diagnosis of idiopathic ISK if no identifiable etiology was found. RESULTS: Herpes simplex virus (HSV) accounted for 71.4% of unilateral active ISK. Idiopathic accounted for 14.3%, and varicella-zoster virus accounted for 8.6% in this group. HSV was the etiologic factor of 50.0% of inactive unilateral cases, whereas 33.3% were idiopathic. Sixty percent of cases of bilateral, active ISK were from idiopathic causes. Syphilis was the cause of 48.5% of bilateral inactive cases. In this group, 33.3% were from idiopathic causes. CONCLUSION: Although syphilis has been recognized for many years as the cause of 90% of cases of ISK, this is no longer true. We demonstrated that active ISK is most commonly caused by HSV or is idiopathic and that, although syphilis is the leading cause of inactive, bilateral ISK, it is responsible for only 18.6% of total cases.

Iatrogenic limbal stem cell deficiency.

PURPOSE: To describe a group of patients with limbal stem cell (SC) deficiency without prior diagnosis of a specific disease entity known to be causative of SC deficiency. METHODS: We performed a retrospective review of the records of all patients with ocular surface disease seen at the University of Minnesota between 1987 and 1996. Patients were categorized according to origin of limbal deficiency. Patients who did not have a specific diagnosis previously described as being causative of limbal deficiency were analyzed. Risk factors, clinical findings, and sequelae were evaluated. RESULTS: Fourteen eyes of 12 patients with SC deficiency not caused by a known diagnosis were described. All eyes had prior ocular surgery involving the corneoscleral limbus. Eleven eyes had been receiving long-term topical medications, and all eyes had concurrent external disease such as pterygium, keratoconjunctivitis sicca, rosacea, herpes simplex virus keratitis, or aphakic or pseudophakic corneal edema. All eyes had superior quadrants affected, corresponding to areas of prior limbal surgery. Sequelae of disease included corneal scarring and neovascularization, with seven eyes having visual acuity of 20/150 or worse. CONCLUSION: Because the epitheliopathy started peripherally and extended centrally in all patients, we believe it represents an SC deficiency. The fact that all patients were affected superiorly, at sites of a prior limbal surgical incision, points to surgical trauma to the SC as the likely major etiologic factor for the deficiency. The surgical trauma to the limbal SC probably made these cells more susceptible to damage from other external disease influences and toxicity from long-term topical medications. Because the SC deficiency is the result of prior ocular surgery and long-term topical medications, we propose the term "iatrogenic limbal stem cell deficiency."