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Biomedical subjects

Russell Pokroy

Publications and source records attributed to Russell Pokroy.

17 recordsLinked to original sources

Cytomegalovirus-associated colitis causing diarrhea in an immunocompetent patient.

Cytomegalovirus (CMV) colitis rarely occurs in immunocompetent patients. We report a case of disabling and life threatening diarrhea in an immunocompetent elderly woman due to CMV colitis. The diagnosis of CMV was based on histological examination of tissues biopsied at colonoscopy, positive CMV antigen and high CMV-IgM titer in peripheral blood samples and a good response to systemic gancyclovir treatment. We conclude that CMV should be considered in the differential diagnosis of colitis in elderly immunocompetent patients.

Age Factors↗

Effect of G-force on bicuspid aortic valve in aviators.

BACKGROUND AND AIMS: Bicuspid aortic valve (BAV) is a common congenital cardiac malformation. The major complications are aortic stenosis (AS), aortic regurgitation (AR), infectious endocarditis and aortic dissection. This paper aims to assess the hemodynamic importance of incidentally-found BAV in military aviators and evaluate the effect of high G-force on disease progression. METHODS: Aviators with BAV were detected by reviewing all cardiac assessment records between 1987 and 2005. All aviators underwent annual flight surgeon examination. Echocardiography was performed as recommended by our cardiologists and flight surgeons. RESULTS: Eight newly diagnosed cases of BAV were found. All of the aviators continued active aviation throughout the study period. Repeat echocardiography demonstrated progressive widening of the aortic diameter in five of the eight aviators. No worsening of valve dysfunction was seen in those with mild aortic regurgitation at diagnosis. Left ventricular dimensions and function did not deteriorate. No new valve complications, including infectious endocarditis, were seen. The age at diagnosis strongly correlated with the root diameter change; both total (r = 0.74, p = 0.02) and annualized (r = 0.78, p = 0.02) change. Over a mean follow-up period of 12.1 years, no difference was seen in the progression of BAV in high-performance as compared to low-performance aviators. CONCLUSIONS: Exposure to G-force and anti-G maneuvers does not appear to worsen cardiac and valve function in aviators with BAV.

Adolescent↗

Intacs adjustment surgery for keratoconus.

PURPOSE: To describe the visual outcome of keratoconic eyes managed with Intacs (Addition Technology, Inc.) that required additional Intacs surgery (defined as any combination of removal, exchange, addition, or shifting of an Intacs segment). SETTING: Private refractive surgery center, Jerusalem, Israel. METHODS: This retrospective noncomparative interventional consecutive small case series studied all eyes of a cohort of 58 keratoconic eyes managed with Intacs that had additional Intacs surgery. The uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, manifest refraction, videokeratography, and patient questionnaires on visual function were assessed. These outcome measures were compared before Intacs implantation, before Intacs adjustment, and 1 year after the final Intacs adjustment. Eyes having any intervention other than Intacs surgery were excluded. RESULTS: Of 58 keratoconic eyes managed with Intacs, 7 had additional Intacs surgery. After the initial Intacs surgery, 6 of these eyes had UCVA < or =20/100 and 1 had UCVA of 20/50. After the final Intacs adjustment, 3 eyes achieved UCVA > or =20/40, 5 achieved UCVA > or =20/70, and 2 remained <20/200. The indications for Intacs adjustments were increased astigmatism in 4 eyes, induced hyperopia (overcorrection) in 3, and undercorrection in 1. One eye had both surgically induced astigmatism and hyperopia. Induced astigmatism and hyperopia were most often managed by removing the superior segment. The undercorrected eye, having initially received a single inferior segment, was treated by implanting a superior segment. CONCLUSIONS: Approximately 10% of keratoconic eyes managed with Intacs may require Intacs adjustment surgery, which often has a good outcome.

Adult↗

Apical hypertrophic cardiomyopathy and arrhythmia in military pilots.

Apical hypertrophic cardiomyopathy (ApHCM), a subtype of hypertrophic cardiomyopathy, may be found incidentally in healthy young adults. Arrhythmias are poor prognostic signs, and are the most frequent cause of sudden cardiac death. We present two cases of military aviators with ApHCM. One was a high-performance jet weapon system operator, who had asymptomatic non-sustained ventricular tachycardia (NSVT) and subsequently a symptomatic episode of paroxysmal atrial fibrillation. The second was a helicopter pilot, who had asymptomatic NSVT. Both aviators continue their aviation duties without exposure to +Gz under a regime of regular thorough cardiac assessment.

Adult↗

Dental fractures on acute exposure to high altitude.

There is little in the literature on dental restoration breakage in the aviation environment since reports of problems in combat aviators in War World II. We report two cases of dental fractures during acute exposure to a hypobaric environment. Case 1 was a young officer who suffered an amalgam restoration breakage during a 25,000-ft decompression chamber simulation. Case 2 occurred in an experienced aviator who had a tooth cusp fracture in a molar with a defective amalgam restoration during an unpressurized helicopter flight to 18,000 ft. In both cases, after removing the defective fillings, deep secondary caries were found; both teeth were successfully restored. Because hard-tissue tooth fracture during a high-altitude flight is a rare event, few flight surgeons or dentists are familiar with this phenomenon. We recommend regular dental examinations with careful assessment of previous dental restorations in aircrew subject to decompression.

Adult↗

Asthma in military aviators: safe flying is possible.

INTRODUCTION: Asthma is considered relatively incompatible with aviation. Firstly, due to the risk of sudden incapacitation, and secondly, due to cold and dry air and other asthmogenic factors characteristic of the aviation environment. The medical requirements for flying fitness of asthmatic aviators are inconsistent between different air services, and many flight surgeons are unfamiliar with the recent developments in asthma management. This study aims to describe our experience with asthmatic aviators and to discuss the medical standards required for flying fitness in chronic asthma. METHODS: The records of all aviators diagnosed with asthma between January 1988 and September 2005 were reviewed. Pulmonary function tests and examination by a pulmonary disease specialist and flight surgeon were performed at least annually. RESULTS: Nineteen Israeli Air Force aviators with asthma were studied. Most were treated with inhaled long-acting beta agonists and corticosteroids. Disease control was satisfactory in more then 90%, with significant worsening in only one case. We had no cases of sudden incapacitation or any other safety breach. One aviator was grounded 23 yr after diagnosis due to deterioration in the severity of the disease, and another aviator was permanently grounded 1 yr after diagnosis. CONCLUSIONS: Adequate asthma control is readily feasible, even in the aviation environment. Long-term inhaled corticosteroids are effective and have few side effects in aviators. Our management approach to aviators with asthma appears to be safe and effective.

Adult↗

Keratoconus managed with intacs: one-year results.

OBJECTIVES: To describe the visual outcome of keratoconus managed with Intacs implantation (Addition Technology Inc, Fremont, Calif) and to define criteria that predict good outcome. METHODS: This retrospective, nonrandomized, comparative, consecutive case series studied 58 eyes of 43 patients with keratoconus managed by Intacs implantation. The outcome measures were analyzed pre-Intacs and 1 year post-Intacs. Preoperative parameters were correlated with outcome. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, videokeratography, and patient questionnaires. RESULTS: Intacs were implanted in all eyes with no intraoperative complications. Six eyes underwent additional Intacs surgery. Post-Intacs, the mean +/- SD UCVA improved from less than 20/200 +/- 0.1 line to 20/50(-3) +/- 3.1 lines, the mean +/- SD BSCVA was unchanged at 20/32 +/- 2.0 lines, the mean +/- SD spherical equivalent improved from -3.88 +/- 1.64 to -1.04 +/- 1.51 diopters (D), and the mean +/- SD astigmatism improved from 3.34 +/- 2.23 to 1.97 +/- 1.51 D. Twenty-five eyes had a good outcome (UCVA> or =20/40). Multiple regression selected BSCVA, astigmatism, and spherical myopia as the preoperative predictors of outcome. CONCLUSIONS: Intacs improve myopia and regular astigmatism in keratoconus. Milder keratoconus (BSCVA>20/32(-2) and astigmatism<3.50 D) and significant spherical myopia (>-1.75) predict better outcome.

Adult↗

Heat stress and carbon monoxide exposure during C-130 vehicle transportation.

INTRODUCTION: Running gasoline engines in a confined space causes heat stress and carbon monoxide (CO) buildup. Loading the C-130 aircraft by driving the vehicles onto the platform may expose the C-130 cabin crew to these environmental hazards. This study was aimed at investigating heat stress and CO exposure in the C-130 cabin during vehicle airlift. METHODS: There were four summer flights (two two-vehicle, two three-vehicle; 2 d, 2 nights) studied. The cabin heat stress index (wet bulb globe temperature, WBGT) and CO levels before vehicle loading (control) were compared with those after vehicle loading. Furthermore, two- and three-vehicle transportations, as well as day and night transportations, were compared. RESULTS: Ground temperature ranged from 18.2 to 33.4 degrees C. Mean heat stress index was higher in vehicle transportation than control flights, the greatest difference being 5.9 degrees C (p < 0.001). The WBGT levels exceeded the recommended exposure limit in 28 of 38 measurements during day flights. The cabin heat stress increased sharply with vehicle loading, and continued to increase for a range of 60-140 min after loading. Elevated cabin CO levels were found in three-vehicle flights as compared with two, and in night flights as compared with day. CONCLUSIONS: In hot climates, C-130 vehicle transportation may exacerbate heat stress. The in-flight heat stress can be predicted by the ambient temperature, duration of the vehicle transportation, and number of transported vehicles. The cabin CO level is related to the number of transported vehicles. We recommend the use of effective environmental control systems during C-130 vehicle transportation in hot climates.

Adaptation, Physiological↗

Head-up tilt test for recurrent syncope in pilots.

Syncope is defined as a sudden temporary loss of consciousness and postural tone that is associated with spontaneous recovery. Vasovagal or neurocardiogenic syncope is a common and usually benign cause of syncope. The mechanism may be cardioinhibitory, vasodepressor, or both. Diagnosis is usually made by a typical patient history with a definite trigger. Although vasovagal syncope is considered a benign condition, its occurrence in an aviator is worrisome, especially if recurrent and without a definite trigger. The head-up tilt test (HUTT) is used as a vasovagal syncope challenge test. A drop in BP and asystole during HUTT suggest a tendency to recurrent vasovagal syncope. We describe two military aviators with recurrent episodes of vasovagal syncope, one with definite triggers and one without. Both had positive HUTTs. The aviator with trigger-defined vasovagal syncope was disqualified from high-performance platforms due to his positive HUTT. The second case was disqualified from all platforms, irrespective of his HUTT result, because a definite trigger was not definable for all his syncopal episodes.

Adult↗

Single Intacs segment for post-laser in situ keratomileusis keratectasia.

PURPOSE: To describe the visual outcome of implantation of a single Intacs segment (Addition Technology Inc.) in eyes with keratectasia after myopic laser in situ keratomileusis (LASIK). SETTING: Private refractive surgery center, Jerusalem, Israel. METHODS: This retrospective, noncomparative, interventional, consecutive, small case series studied 5 eyes of 5 patients with post-LASIK keratectasia from 3 refractive laser centers treated by Intacs implantation. Before and 9 months after Intacs implantation, the uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, keratometry, videokeratography, inferior-superior asymmetry, and patient questionnaires about visual function were assessed. RESULTS: Intacs implantation was performed 17 to 32 months post LASIK with no intraoperative complications and no loss of visual acuity. After implantation, the UCVA improved 8, 4, 3, 0.5, and 5 lines and the BSCVA, 2, 2.5, 1, 0.5, and 2 lines. The mean manifest refraction spherical equivalent improved from -1.60 diopters (D) +/- 1.67 (SD) to -0.80 +/- 1.05 D. The mean manifest astigmatic correction decreased from -3.9 +/- 2.96 to -2.46 +/- 2.77 D. Corneal topography showed improved inferior steepening and less irregular astigmatism. The mean inferior-superior asymmetry improved from 7.88 +/- 4.59 to 2.46 +/- 2.77 D. Self-reported visual symptoms improved significantly in Cases 1, 2, and 5 and slightly in Cases 3 and 4. CONCLUSIONS: Implantation of a single Intacs segment inferiorly appeared to improve progressive myopia and regular and irregular astigmatism in eyes with corneal ectasia after LASIK. With further study, this technique may prove to be an effective, relatively noninvasive approach.

Adult↗

Occurrence and progression of diabetic retinopathy after phacoemulsification cataract surgery.

PURPOSE: To evaluate the risk factors associated with the occurrence and progression of diabetic retinopathy (DR) after phacoemulsification cataract surgery. SETTING: Department of Ophthalmology, Kaplan Medical Center, Rehovot, Israel. METHODS: The medical charts of 52 eyes of 48 consecutive patients who had phacoemulsification were retrospectively reviewed. The occurrence of DR (new development of any DR) and progression (DR requiring laser treatment) were correlated with patients' age, sex, duration of diabetes, control of diabetes, hypertension, ischemic heart disease, and surgical technique. Exclusion criteria were significant ocular conditions and a follow-up shorter than 6 months. RESULTS: The occurrence of DR was associated with male sex, and among males, with the duration of the disease. An analysis including all patients showed that postoperative progression of preexisting DR was not associated with any factor except poor blood sugar control. Neither the occurrence nor progression of DR was associated with reduced visual acuity CONCLUSIONS: The occurrence and progression of DR after phacoemulsification were associated with different factors. Poor systemic control of diabetes increases the risk.

Aged↗

Self-inflicted (factitious) conjunctivitis.

PURPOSE: To describe the diagnosis and management of self-inflicted factitious conjunctivitis in conscripted soldiers. DESIGN: Prospective, noncomparative, consecutive case series. PARTICIPANTS: Seventeen conscripted soldiers. METHODS: Soldiers with chronic conjunctivitis (>3 weeks) were referred by ophthalmologists, and cases of shorter duration were referred by primary-care physicians. All cases underwent thorough ophthalmic and systemic history and examination, as well as questioning regarding their military units, military duties, and social background. Exclusion criteria were any condition that may cause conjunctivitis. Inferior fornix specimen microscopy and culture and eye photography were performed in most cases. In cases suspected of self-inflicted conjunctivitis all medication, besides lubricant drops, was stopped. Underlying psychosocial problems were investigated and managed. Cases were followed for at least 3 months after resolution of the conjunctivitis, at which point the diagnosis was confirmed, and the case entered the analysis. MAIN OUTCOME MEASURES: Resolution of the conjunctivitis. RESULTS: Seventeen consecutive cases of self-inflicted conjunctivitis, 8 of long duration and 9 of short duration, were studied. All cases demonstrated inconsistent clinical findings. The ocular signs most suggestive of self-inflicted conjunctivitis were purulent discharge purposely left on the lashes and periorbital skin, discharge more severe than in conjunctival hyperemia, less conjunctival chemosis than in hyperemia, mainly inferior conjunctival involvement, and an uninvolved cornea. Five of the 8 chronic cases had significant underlying psychologic or social problems. Their conjunctivitis resolved only after their underlying problems were addressed. Two cases admitted introducing freshly scraped dental plaque into the lower conjunctival sac. In the remaining 15 the similarity of the clinical findings suggested that a similar method was used. CONCLUSIONS: In the context of a subject standing to gain by assuming the sick role and after exclusion of ocular pathology, self-inflicted conjunctivitis can be reliably diagnosed by noting the characteristic clinical profile. Effective management includes addressing the underlying psychologic and social problems.

Adolescent↗

Retinal detachment in eyes with vitreous loss and an anterior chamber or a posterior chamber intraocular lens: comparison of the incidence.

PURPOSE: To compare the incidence of retinal detachment within 6 months of cataract surgery complicated by vitreous loss in eyes with a posterior chamber intraocular lens (PC IOL) or an anterior chamber IOL (AC IOL). SETTING: Department of Ophthalmology, Kaplan Medical Center, Rehovot, Israel. METHODS: In this retrospective consecutive nonrandomized comparative case series, all cases of cataract surgery complicated by vitreous loss between January 1991 and March 1998 were reviewed. Included were patients who had thorough anterior vitrectomy and primary IOL implantation and at least 6 months follow-up. Exclusion criteria were congenital and traumatic cataract, previous intraocular surgery, and previous retinal detachment. Patients receiving an unsutured single-piece poly(methyl methacrylate) (PMMA) PC IOL formed the PC group, while those receiving flexible open-loop single-piece PMMA AC IOLs formed the AC group. The incidence of postoperative retinal detachment in the 2 groups was compared. RESULTS: Of the 151 eyes of 149 patients, 66 received a PC IOL and 85 received an AC IOL. Two eyes (3.0%) in the PC group and 2 (2.4%) in the AC group developed retinal detachment; the difference between groups was not statistically significant (P = 1.00, Fisher exact test). CONCLUSIONS: In eyes that have vitreous loss and thorough anterior vitrectomy, AC IOL implantation did not appear to increase the incidence of retinal detachment.

Aged↗

p53 expression in the normal murine eye.

PURPOSE: The tumor-suppressor gene p53 encodes a phosphoprotein involved in the control of cell growth. Its expression and function have been documented in malignancy, apoptosis, and other abnormal cell proliferation processes. Recently, expression of p53 has been demonstrated in certain normal tissues, including whole eye. The purpose of the study was to map and to characterize expression of p53 in the normal murine eye. METHODS: Eyes of adult C57BL/6 mice were enucleated after death by CO2 narcosis. Expression of p53 in frozen sections of whole cryoprotected eyes was mapped by indirect immunofluorescence microscopy using the anti-p53 monoclonal antibodies 248 and 421 and the polyclonal antibody FL-393. Additionally, eyes were freshly dissected to separate the various ocular tissues. In these ocular tissues, expression of p53 was quantitated with ELISA and Western blot analyses. RESULTS: Strong expression of p53 was observed in various normal ocular tissues. The corneal and conjunctival epithelium exhibited very high cytoplasmic p53 protein levels. High nuclear p53 protein staining was seen in the lens epithelial cells of the central and pre-equatorial zones and in the lens fiber nuclear bow, situated posterior to the epithelial germinative zone. Cells of the actual lens germinative zone did not stain for p53 protein. Low levels of p53 protein were expressed in retinal tissue. CONCLUSIONS: High levels of p53 protein are found in various normal murine ocular tissues, especially the corneal and conjunctival structures and the lens epithelium. Each of these tissues demonstrate unique patterns of staining.

Animals↗

Evaluation of systemic allergy in a jet aviator.

Cholinergic urticaria and exercise-induced anaphylaxis (EIA) are related conditions. Cholinergic urticaria is caused by a rise in body core temperature and usually results in pruritus, skin lesions and, rarely, in serious respiratory and cardiovascular compromise. EIA can result in a cardiovascular compromise and syncope. Ingestion of certain foods may be associated with EIA. A 41-year-old jet pilot complained of 3-month onset of pruritus and urticaria during treadmill exercise. On one occasion, after a routine exercise bout, albeit with pruritus and urticaria, he experienced two short episodes of syncope. Treatment with a nonsedating H1-receptor antagonist was started. He underwent a unique challenge test that we designed. This included passive warming as well as exercising in a hot (temperature of 40 degrees C at 40% humidity) environment. After passing this test uneventfully, the pilot was returned to jet flight with a copilot and, subsequently, to full active duty.

Adult↗