Laser in situ keratomileusis: literature review of a developing technique

We reviewed papers published in peer-reviewed journals describing techniques and results of laser in situ keratomileusis (LASIK) and summarized the instruments used, nomograms, preoperative and postoperative refractions, predictability, outcome, safety, and complications. We performed a similar review of abstracts published in the abstract books of the 1996 meeting of the International Society of Refractive Surgery, the 1997 meeting of the Association for Research in Vision and Ophthalmology, and the 1997 meeting of the American Society of Cataract and Refractive Surgery. The number of LASIK and photorefractive keratectomy (PRK) patients described in the abstracts were sorted by city. Mean weighted latitudes were calculated and compared for each procedure. The mean preoperative refraction in the papers was -12.59 diopters (D), which was statistically higher than that in the abstracts, -8.71 D (P < .001), and the mean postoperative refraction, -1.10 and + 0.93 D, respectively. The mean percentage of cases within +/- 1.00 D was 67.0% in the papers and 82.5% in the abstracts. Uncorrected visual acuity (UCVA) of 20/40 or better was achieved in 49.2% of eyes in the papers and 83.2% of those in the abstracts; a UCVA of 20/20 or better was achieved in 22.0 and 56.6%, respectively. The portion of eyes that lost two or more lines of best corrected visual was 8.0% in the papers and 0.9% in the abstracts. Complications in the papers included irregular flap (4.0%), incomplete cut (2.5%), free cap (4.9%), perforated lenticule (2.6%), short flap (3.0%), sliding flap (1.4%), interface debris (6.8%), central island (5.3%), decentration (4.7%), epithelial ingrowth (4.3%), induced astigmatism (5.1%), wrinkles (5.9%), haze (8.7%), night vision problems (14.0%), and reoperation (8.2%), Mean latitude for LASIK cases (27.00 degrees +/- 13.73 [SD] was significantly lower than that for PRK cases (42.85 +/- 11.7 degrees). Visual outcomes of LASIK surgery show significant improvements when recent abstracts are compared with published papers. This may reflect continued improvement in the surgical techniques, surgeons' skills, and visual outcomes.     

Models of community care for severe mental illness: a review of research on case management

We describe different models of community care for persons with severe mental illness and review the research literature on case management, including the results of 75 studies. Most research has been conducted on the assertive community treatment (ACT) or intensive case management (ICM) models. Controlled research on ACT and ICM indicates that these models reduce time in the hospital and improve housing stability, especially among patients who are high service users. ACT and ICM appear to have moderate effects on improving symptomatology and quality of life. Most studies suggest little effect of ACT and ICM on social functioning, arrests and time spent in jail, or vocational functioning. Studies on reducing or withdrawing ACT or ICM services suggest some deterioration in gains. Research on other models of community care is inconclusive. We discuss the implications of the findings in terms of the need for specialization of ACT or ICM teams to address social and vocational functioning and substance abuse. We suggest directions for future research on models of community care, including evaluating implementation fidelity, exploring patient predictors of improvement, and evaluating the role of the helping alliance in mediating outcome.     

Cloning of aas, a gene encoding a Staphylococcus saprophyticus surface protein with adhesive and autolytic properties

A gene encoding a novel cell wall-associated protein of Staphylococcus saprophyticus that binds fibronectin and to sheep erythrocytes has been cloned and sequenced. The 4392 bp open reading frame codes for an amino acid sequence that is quite similar to the Atl, an autolysin, of Staphylococcus aureus and to the AtlE of S. epidermidis. The two regions of most pronounced homology code for an N-acetyl-muramyl-L-alanine amidase and for an endo-beta-N-acetyl-D-glucosaminidase. The cloned protein lysed cells of S. saprophyticus and Micrococcus luteus exogenously. Subcloning localized the enzymatic activities to the regions of high homology and demonstrated that the interposed sequence is responsible for the adhesive activities. Two allelic replacement mutants were constructed that lacked autolytic activity and adhesive properties. The N-terminal portion of the protein contains seven highly conserved, contiguous repeats with no similarity to published sequences. It lacks the motifs typical of Gram-positive surface proteins and shows a different overall organization. This autolysin/adhesin of S. saprophyticus (Aas) appears to represent a new class of staphylococcal adhesins.     

Endothelial cell injury caused by Candida albicans is dependent on iron

MRL-lpr/lpr mice spontaneously develop manifestations of autoimmunity including arthritis, vasculitis, and glomerulonephritis. The paramagnetic molecule nitric oxide has been implicated as an effector molecule in initiation and propagation of these inflammatory conditions. In this study, we utilized electron paramagnetic resonance spectroscopy to directly detect nitrosylated protein complexes as products of nitric oxide in whole blood and in kidneys of MRL-lpr/lpr mice. Electron paramagnetic resonance spectra of blood samples from MRL-lpr/lpr mice showed nitrosyl hemoglobin species. Amounts of blood nitrosyl hemoglobin in MRL-lpr/lpr mice were significantly increased as compared to age-matched control mice. Electron paramagnetic resonance spectra of MRL-lpr/lpr kidney tissue exhibited a signal characteristic of a dinitrosyl-iron-dithiolate complex at g approximately 2.04. Formation of nitrosylated nonheme protein in diseased kidneys is associated with development of glomerulonephritis in the autoimmune mice. The presence of nitrosylated nonheme protein indicates the formation of nitric oxide within the kidneys of the diseased mice signifying in situ renal nitric oxide formation.     

Enhancement of 5-aminolaevulinic acid-induced photodynamic therapy in normal rat colon using hydroxypyridinone iron-chelating agents

Currently, the clinical use of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PPIX) for photodynamic therapy (PDT) is limited by the maximum tolerated oral ALA dose (60 mg kg(-1)). This study investigates whether hydroxypyridinone iron-chelating agents can be used to enhance the tissue levels of PPIX, without increasing the administered dose of ALA. Quantitative charge-coupled device (CCD) fluorescence microscopy was employed to study PPIX fluorescence pharmacokinetics in the colon of normal Wistar rats. The iron chelator, CP94, when administered with ALA was found to produce double the PPIX fluorescence in the colonic mucosa, compared with the same dose of ALA given alone and to be more effective than the other iron chelator studied, CP20. Microspectrofluorimetric studies demonstrated that PPIX was the predominant porphyrin species present. PDT studies conducted on the colonic mucosa showed that the simultaneous administration of 100 mg kg(-1) CP94 i.v. and 50 mg kg(-1) ALA i.v. produced an area of necrosis three times larger than similar parameters without the iron-chelating agent with the same light dose. It is possible, therefore, to increase the amount of necrosis produced by ALA-induced PDT substantially, without increasing the administered dose of ALA, through the simultaneous administration of the iron-chelating agent, CP94.     

Magnetic resonance angiography of mesenteric arteries. A review

There has been continued development of MRI techniques for evaluating mesenteric vascular disease. Contrast-enhanced magnetic resonance angiography (MRA) can provide reproducible high resolution, high contrast images of the arterial and venous mesenteric vasculature and may allow detection of segmental ischemia by detection of segmental delayed mesenteric or bowel wall enhancement. Cine phase-contrast MRA can provide additional information about the rate and volume of flow within the major mesenteric arteries and veins. Real-time MRI can provide interactive visualization of the mesenteric vessels in any plane, and with suitable bowel contrast, it can be used to monitor global and segmental small bowel motility. With in vivo MR oximetry, flow independent measurements of the T2 relaxation of blood allow the oxygen saturation of the mesenteric circulation to be determined. These MR techniques can be combined for evaluating both anatomic and functional aspects of the mesenteric circulation.     

Kidney transplantation after a severe form of pseudotumor cerebri

Pseudotumor cerebri is a syndrome characterized by intracranial hypertension (intracranial pressure >200 mmH2O) and a normal ventricular system. The diagnosis should be made as early as possible to prevent impairment of vision. Several diseases have been reported in association with pseudotumor cerebri in pediatric patients, and have been occasionally also noted with chronic renal failure, heart and renal transplantation. We report a 7-year-old boy who complained of severe headaches and visual impairment 2 years after hemodialysis for renal hypoplasia. Pseudotumor cerebri was suspected and, despite treatment with corticosteroids, acetazolamide, and lumboperitoneal diversion, visual impairment worsened. Bilateral optic nerve sheath decompression (ONSD) was performed without success and the child completely lost his vision within 2 weeks. He was successfully transplanted 2 months later. Two years post transplantation, the blind child has a normal renal function and school performance. Pseudotumor cerebri must be rapidly suspected in a child with renal failure suffering from headaches and papilledema. Visual loss may progress rapidly and ONSD seems to be the best surgical treatment when medical treatment fails. In this patient renal transplantation was well tolerated, with no deterioration in the neurological status over 2 years of follow-up.     

Changes in physical activity, mortality, and incidence of coronary heart disease in older men

BACKGROUND: We studied the relations between physical activity and changes in physical activity, all-cause mortality, and incidence of major coronary-heart-disease events in older men. METHODS: In 1978-80 (Q1), 7735 men aged 40-59 were selected from general practices in 24 British towns, and enrolled in a prospective study of cardiovascular disease, which included physical activity data. In 1992 (Q92), 12-14 years later, 5934 of the men (91% of available survivors, mean age 63 years) gave further information on physical activity and were then followed up for a further 4 years. The main endpoints were all-cause mortality during 4 years of follow-up from Q92, and major fatal and non-fatal coronary-heart-disease events during 3 years of follow-up from Q92. FINDINGS: Among 4311 men with no history of coronary heart disease, stroke, or "other heart trouble" by Q92 and who did not report "poor health", there were 219 deaths. In the inactive/occasionally active, light, moderate, and moderately vigorous/vigorous activity groups there were 101 (18.5/1000 person-years) 48 (11.4), 23 (7.3), and 47 (9.1) deaths, respectively (adjusted risk ratios 1.00, 0.61 [95% CI 0.48-0.86], 0.50 [0.31-0.79], 0.65 [0.45-0.94]). Men who were sedentary at Q1 and who began at least light activity by Q92 had significantly lower all-cause mortality than those who remained sedentary, even after adjustment for potential confounders (risk ratio=0.55 [0.36-0.84]). Physical activity improved both cardiovascular mortality (0.66 [0.35-1.23]) and non-cardiovascular mortality (0.48 [0.27-0.85]). The relation between physical activity at Q92, changes in physical activity, and mortality were similar for men with pre-existing cardiovascular disease. INTERPRETATION: Maintaining or taking up light or moderate physical activity reduces mortality and heart attacks in older men with and without diagnosed cardiovascular disease. Our results support public-health recommendations for older sedentary people to increase physical activity, and for active middle-aged people to continue their activity into old age.