Intraocular lens performance in air, in water, and in situ: a computer study

Computer analysis is used to predict performance of four intraocular lenses with assigned values of aberration. Cylinder error and asphericity error are used as examples of possible manufacturing errors. Three measures of performance are calculated: maximum optical path difference, root mean square optical path difference, and modulation transfer function. For evaluation in air these standard test conditions are assumed: collimated green light incident on the convex surface of a plano-convex lens, with a 3 mm aperture. All four lenses show substantially improved performance in water compared to air, and a further improvement in the simulated eye (i.e., in situ). However, an aberrated 30 diopter (D) lens with performance in air comparable to an aberrated 20 D lens, performs worse in situ than does the 20 D lens. This suggests that a performance test in air that is suitable for a 20 D lens (e.g., 100 line pairs per millimeter resolution) may not be adequate for a 30 D lens. A test in air at 30% resolution efficiency may be more suitable.     

A REVIEW OF THE CTRETACEOUS FORMATIONS IN THE ARABIAN PENINSULA AND GULF: PARTII. MID-CRETACEOUS (WASIA GROUP) STRATIGRAPHY AND PALEOGEOGRAPHY

The stratigraphic sequence of the "Middle" Cretaceus Wasia Group in the Arabian Gulf, and the terminology used, is reviewed. Type sections and synonyms are established for the succession in the United Arab Emirates. An historical introduction provides a key to the understanding of the varied formational and member names in currnet use.
Facies distribution maps show tha shallow-water, predomantly carbonate belts extend across the whole region. Two clastic-carbonate cycles are apparent in the NE part of the Gulf, the lower Nahr Umr-Mauddud cycle and an upper Wara-Mishrif cycle. The Upper cycle is surrounds a slightly deeper intracratonic basin which developed in late Albian-Earllly Cenomanian time.     

Apoptosis: molecular regulation of cell death

This article focuses on the few disorders that produce chronic cholestasis in infants and children. Cholestasis is defined, and a framework for thinking about pathophysiology is provided. Medical management is discussed in the context of the consequences and complications of chronic cholestasis. The limited differential for chronic cholestasis is discussed, and approaches to diagnosis and management of specific disorders are provided.     

Prevention of traffic accidents

To inform nursing professionals about their role in the prevention of traffic accidents, a grave health-related problem, is the purpose of this article. To begin with, factors which can deteriorate one's capacity to drive vehicles, and over which nursing professionals can intervene, will be presented. These factors include alcohol, other drugs, medicines, individual morbidity, the factor of aging and the use of security devices. A special reference will be made about widely used medicines. Finally the role that a nurse can fulfill will be explained. This role can be directed to various sections of the general public, be of varying natures, be exercised with greater or lesser ease, and lastly can have more or less effect upon those to whom it is destined.     

Unintegrated circular HIV-1 DNA in the peripheral mononuclear cells of HIV-1-infected subjects: association with high levels of plasma HIV-1 RNA, rapid decline in CD4 count, and clinical progression to AIDS

We observed 36 HIV-infected patients to evaluate whether the presence of tandem 2-long terminal repeat circular unintegrated HIV-1 DNA (2-LTR) in peripheral blood mononuclear cells (PBMC) at baseline was associated with acceleration of HIV disease. Detection of 2-LTR at baseline correlated with high plasma HIV-1 RNA levels (p < .01), recovery of culturable HIV-1 from plasma (p = .02), and progression to AIDS during follow-up (p = .01). More patients with 2-LTR (68%) than without 2-LTR (31%) had a decline in CD4 levels of >50 cells/mm3 over the first 18 months of follow-up (p = .04), and the average annual CD4 decline was 35% in patients with 2-LTR compared with 16% in those without 2-LTR (p = 0.06). Detection of 2-LTR in PBMC at baseline was an independent predictor of high plasma HIV-1 RNA levels and subsequent CD4 cell decline in this cohort of patients with predominantly nonsyncytium-inducing (NSI) isolates at baseline. The presence of 2-LTR in PBMC appears to be reflective of ongoing HIV-1 replication, as measured by plasma HIV-1 RNA levels, and identifies persons at risk for immunologic and clinical decline.     

Mitochondrial respiratory chain succinate-cytochrome-c oxidoreductase deficiency and hepatic cirrhosis

OBJECTIVES: The current need to evaluate necessity and cost of diagnostic and therapeutic procedures extends to transplant services. We reviewed our experience over the past 3 years as we have moved away from routine post-transplant nuclear medicine scans, ultrasounds, and cystograms. METHODS: From January 1, 1992 to December 31, 1994, 252 kidney transplants were performed at Virginia Mason Medical Center. There were 74 live donor and 178 cadaver donor kidneys transplanted. The records of these patients were reviewed for the type and number of post-transplant imaging done during their initial hospitalization. RESULTS: During the study period, the number of post-transplant imaging studies per patient decreased from 2.7 to 1.4 (P = 0.000), the percentage of patients discharged without any studies rose from 2.8% to 24.4% (P = 0.001), and the trend in 1-year actual graft survival increased from 84.7% to 93.0% (P = 0.187). CONCLUSIONS: Post-transplant imaging studies can be safely reduced. Many patients with good initial graft function can avoid having any studies.     

Penile vibratory stimulation in spinal cord injured men: optimized vibration parameters and prognostic factors

OBJECTIVE: To study the efficacy of penile vibratory stimulation (PVS) with optimized vibration parameters in spinal cord injured (SCI) men and to examine prognostic factors for success. DESIGN: Case series. SETTING: University hospital outpatient clinic. PATIENTS: Thirty-four consecutive SCI men seeking fertility treatment. INTERVENTION: PVS with optimized vibration parameters to induce reflex ejaculation. MAIN OUTCOME MEASURES: Ejaculatory response; semen analysis. RESULTS: Antegrade ejaculation was seen in 65% of patients. High rates were seen in lesions above T10 (81%) and in presence of hip flexion and bulbocavernosus reflexes (77%). Of men with lesions above T10, those with a penile prosthesis had lower ejaculation rates (40% vs 90%). Average total sperm counts were 968 million, with 26% motility. CONCLUSIONS: High rates of ejaculation are seen with optimized vibration parameters, especially in men with lesions above T10 and intact lower spinal reflexes. A penile prosthesis may impair success with PVS.     

Conformational changes of the yeast mitochondrial adenosine diphosphate/adenosine triphosphate carrier studied through its intrinsic fluorescence. 1. Tryptophanyl residues of the carrier can be mutated without impairing protein activity

During the transport process the mitochondrial adenine nucleotide carrier (Ancp) undergoes conformational changes which result in modifications of the intrinsic fluorescence of the carrier. To further study these changes by a fluorometric approach, the three tryptophanyl residues (Trp87, Trp126, and Trp235) of the Saccharomyces cerevisiae Anc2p were individually mutated to their tyrosine counterparts. The resulting mutated genes (two-Trp, one-Trp or Trp-less variants) were integrated at the ANC2 locus. A prerequisite for such studies is that all the engineered carrier molecules are still able to catalyze ADP/ATP exchange. The cellular characteristics of the strains expressing the mutated Anc2p and the biochemical properties of the variant Anc2p in mitochondria were examined. Although Trp87 is absolutely conserved in all 30 available Ancp sequences, none of the tryptophanyl residues is essential to the carrier protein folding and the transport activity. The mutated and wild-type Anc2p were expressed to the same level, as evidenced by both ligand binding and immunochemical analyses. When isolated in the presence of detergent, all the variant Anc2p preparations contained ergosterol in similar amounts (9 mol/mol of 35 kDa Anc2p) but no specific interaction was revealed. Our results show that the tryptophanmutated Anc2p are suitable for fluorescence studies, which are reported in the accompanying paper by Roux et al. [(1996) Biochemistry 35, 16125-16131].