Single-shot calibration of soft x-ray mirrors using a sinusoidal transmission grating.

Calibration of soft x-ray diagnostics is a challenge due to the lack of laboratory-size calibrated sources. An in situ calibration method for newly developed x-ray mirrors, is presented. The x-ray source is produced by laser-matter interaction, and twin transmission gratings which create two identical dispersion lines. The gratings have a sinusoidal transmission function, which produces a highly precise high-orders free spectrum. An x-ray mirror interacts with one of the dispersion lines, and the mirror efficiency curve as a function of wavelength is extracted. Mirror efficiency shows good agreement with the literature, and evidence of water layer may justify the need of in situ calibration.

Biological glue in pterygium surgery with a rotational flap or sliding flaps.

PURPOSE: To compare 2 surgical approaches to conjunctival flap placement during pterygium surgery using a biologic adhesive: single rotational flap and double sliding flaps. METHODS: Thirty-three consecutive patients (34 eyes) with primary pterygium were assigned prospectively and randomly to receive pterygium surgery with either 1 rotational flap (group A, 19 eyes) or double sliding flaps (group B, 15 eyes) by using a biologic adhesive to secure the flaps. The patients were followed for 24 weeks. RESULTS: In group A, 1 (5.3%) flap was lost because of ischemia, whereas all the others remained in position and became fully integrated. In group B, 4 (26%) flaps did not retain their primary position. In 2 (13%) eyes, the superior and inferior flaps partially dehisced, resulting in a 2- to 3-mm gap; in 1 (6.5%) eye, the inferior flap dehisced completely and retracted to the lower fornix; and in 1 (6.5%) eye, both flaps completely dehisced and retracted, leaving an area of bare sclera. CONCLUSIONS: The use of tissue adhesive is a promising technique in pterygium surgery. In this study, gluing 1 rotational flap resulted in excellent postoperative results, but it seemed less suitable for use with double sliding flaps.

Screening and treating amblyopia: are we making a difference?

PURPOSE: To determine the rate of amblyopia in native Jewish Israelis compared with those who immigrated from the former Soviet Union (U.S.S.R.) after they were 10 years of age. METHODS: Health records of all 16-year-old subjects examined in the Israel Defense Forces Recruitment Center between 1998 and 2003 were analyzed. The number of subjects with best corrected visual acuity (BCVA) of 6/12 or less in at least one eye among native Israelis and among those who immigrated to Israel from the U.S.S.R. after they were 10 years of age was determined. Subjects who had any ocular disease except cataract, corneal opacity, strabismus, or ptosis were excluded. RESULTS: Of 305,712 subjects examined between 1998 and 2003, 292,255 were enrolled in the study. Of those, 260,186 (89%) were born in Israel and 32,069 (11%) were born in the U.S.S.R. and immigrated to Israel after they were 10 years of age. There were 2565 (0.98%) native Israelis and 483 (1.5%) immigrants who had BCVA of 6/12 or less in at least one eye (chi(2) test, P < 0.00001). The rate of amblyopia among subjects who had refractive errors was 14.6% among immigrants, as opposed to 8.0% among native Israelis (P < 0.0001), whereas amblyopia rates among those with strabismus, cataract, or ptosis were similar in native Israelis and immigrants (34.4%, 38.6%, 12.8% as opposed to 34%, 37.5%, 15.4%, respectively, P = 0.5-0.61). CONCLUSIONS: The difference in the rate of refractive amblyopia as opposed to strabismic and deprivation amblyopia may be due to the difference in vision screening methods between both countries.

Israel: a comparison of army personnel satisfaction rates in different primary healthcare settings.

The Israeli medical corps has recently been examining different primary healthcare settings for home-front career army personnel. This study compares the satisfaction rates of this unique population in different primary healthcare settings. Previously validated patient-satisfaction surveys were conducted 4 months apart in 10 large primary care clinics that treat home-front army career personneL. Satisfaction was highest in a civilian hospital-based primary care clinic. The specialized military career personnel clinics produced less satisfaction than the hospital setting, according to the survey; however, the differences were not statistically significant. Patient satisfaction was significantly lower in the classic military-based general practices. The hospital setting of civilian primary care created higher satisfaction in aspects of accessibility, availability, and interpersonal relationships. However, the patients' perception of quality of care was lower than in the other settings.

Benign opsoclonus in preterm infants.

Opsoclonus is a rare childhood ocular motility disorder characterized by irregular, chaotic, involuntary bursts of high amplitude, back-and-forth oscillations of the eyes,without pause intervals. Although this disorder is associated with neuroblastoma and other neural crest tumors, as well as with other neurologic abnormalities, it was also reported in healthy infants. The purpose of this study was to prospectively investigate the prevalence of opsoclonus in preterm infants, and to find any conditions associated with this disorder. Between August 2000 and April 2003, 528 consecutive preterm infants with gestation of less than 33 weeks or birth weight of less than 1500 gm were examined in accordance with our medical centers' retinopathy of prematurity screening policy. Opsoclonus was identified in three patients (0.6%), who were all otherwise physically and neurologically intact. One patient developed threshold retinopathy of prematurity that resolved after laser treatment. On follow-up examinations, the opsoclonus gradually disappeared by the age of 6 months in all infants,with no other complications. This study suggests that opsoclonus can be a benign, self-limiting phenomenon in preterm infants as was previously reported in term infants. However, because of the risk of severe associated illnesses, it is prudent to perform several diagnostic procedures and to continue careful follow-up until this phenomenon spontaneously resolves.

Risk factors for surgical site infection in the patient with spinal injury.

STUDY DESIGN: A retrospective chart review of 1561 patients with spinal injury was conducted over a 4-year period. OBJECTIVES: To determine the rate of surgical site infection in the spinal trauma population, to compare infection rates after spinal operations for elective and traumatic indications, and to identify risk factors for postoperative wound infections in the traumatic subpopulation. SUMMARY OF BACKGROUND DATA: Surgical site infection after spinal operations is a dreaded complication. Risk factors have been investigated previously, but the subset of patients with acute traumatic spinal injury may be distinct. METHODS: The hospital's infection control program was used to identify surgical site infections after spinal operations, and infection rates were calculated. Data including patient characteristics, severity of injury indicators, surgical factors, and perioperative management factors were collected for the patients presenting with acute spinal injury over a 4-year period. RESULTS: Postoperative wound infections developed in 24 of 256 patients. This infection rate of 9.4% was significantly (P < 0.001) higher than for elective spinal operations during the same period (3.7%). Risk factors found to be independently significant included delay until operation, increased postoperative intensive care unit stay, single (neurosurgical or orthopedic) versus combined operative team. CONCLUSIONS: Risk factors for surgical site infection in the acute trauma setting are identified. Two surgical teams may be involved without causing a higher rate of infection.

Efficiency of P-glycoprotein-mediated exclusion of rhodamine dyes from multidrug-resistant cells is determined by their passive transmembrane movement rate.

The aim of the present study was to examine the relationship between the rate of the passive transmembrane movement of multidrug resistance (MDR)-type substrates and the ability of P-glycoprotein to extrude them from MDR cells. For this purpose, seven rhodamine dyes were examined for their P-glycoprotein-mediated exclusion from MDR cells, their localization in wild-type drug-sensitive cells, their capacity to stimulate the ATPase activity of P-glycoprotein reconstituted in proteoliposomes, and their transmembrane movement rate in artificial liposomes. All these rhodamine dyes were accumulated in wild-type drug-sensitive cells and were localized mainly in the mitochondria. All the dyes tested were substrates of reconstituted P-glycoprotein and cellular P-glycoprotein and were excluded to a variable degree from MDR cells. The transmembrane movement rate proved the major factor determining the efficacy of the P-glycoprotein-mediated exclusion of rhodamine dyes from MDR cells. Thus, rhodamine B, the poorest cellular P-glycoprotein substrate, exhibited a high affinity toward reconstituted P-glycoprotein, but was the fastest membrane-traversing dye. In contrast, tetramethylrosamine, the best cellular MDR probe, exhibited high affinity toward reconstituted P-glycoprotein and slow transmembrane movement rate. Therefore, an anticancer drug with a fast transmembrane movement rate is expected to overcome the MDR phenomenon. Furthermore, the widely used MDR marker, rhodamine 123, was a poor cellular MDR substrate compared with other rhodamine dyes, especially tetramethylrosamine, which was a superior cellular MDR substrate for functional dye-exclusion studies.

The role of passive transbilayer drug movement in multidrug resistance and its modulation.

The successful lowering of the intracellular concentration of multidrug resistance (MDR)-type drugs by P-glycoprotein (Pgp) relies on its ability to overcome the passive influx rate of each MDR-type drug. Thus, the aim of the present work was to study the effect of passive transbilayer drug movement on the multidrug resistance and its modulation. Fluorescence quenching studies indicated that whereas the Pgp substrate rhodamine 123 traverses an artificial lipid membrane with a lifetime of 3 min, the transbilayer movement rate of the MDR modulators, quinidine and quinine, was too fast to be detected with present methods. Transbilayer movement rates of drugs and modulators were estimated from their equilibration rate throughout artificial multilamellar vesicles. The equilibration rate of five selected modulators was faster than the equilibration rate of five representative MDR-type drugs tested, which was comparable with the rate of rhodamine 123 equilibration. Moreover, the carrier-type peptide ionophore, valinomycin, which is freely mobile in the membrane, inhibited Pgp-mediated efflux of rhodamine 123 from MDR cells. In contrast, the channel-forming ionophore gramicidin D, a Pgp substrate that flip-flops slowly across the membrane, did not modulate cellular Pgp activity. Pgp, with a turnover number of about 900 min-1 can keep pace with the influx of an MDR-drug like rhodamine 123 exhibiting a transbilayer movement with a lifetime of minutes. On the other hand, Pgp would fail to protect MDR cells against cytotoxic drugs that are freely mobile through biological membranes and that re-enter cells faster than their Pgp-mediated active efflux rate. The relatively fast transbilayer movement exhibited by MDR modulators suggest that in contrast to MDR-type drugs, MDR modulators traverse the plasma membrane faster than the maximal expulsion rate of Pgp.