Detection of the carrier state of X-linked retinoschisis

We determined the extent of suppressive rod-cone interaction in 11 obligate carriers and eight potential carriers of X-linked retinoschisis from eight families. Despite otherwise normal ophthalmoscopic and functional testing, all of the obligate heterozygous carriers demonstrated a complete absence of normal rod-cone interaction. Of the potential heterozygous carriers, three had normal rod-cone interactions, two had no detectable interaction, and two yielded technically unsatisfactory results. This lack of rod-cone interactions allows heterozygous individuals to be identified clinically and has implications concerning the origin of this inherited disorder.     

Separable evoked retinal and cortical potentials from each major visual pathway: preliminary results.

Single cell experiments in primates show that there are two major parallel pathways named after the lamination in the lateral geniculate nucleus. Each of these systems can be preferentially excited by appropriate stimuli. Here we report that in man the polarity of the evoked potentials both in retina and in cortex depends on which of these pathways is stimulated. The identification of the resulting waveforms is thereby simplified--a matter of practical importance. The fact that at retina and cortex there are characteristic potentials may reflect the different cell biology of the two pathways.     

2-甲酰(乙酰)取代喹啉缩氨基硫脲的合成

缩氨基硫脲类化合物有抗肿瘤、抗病毒和抗菌等多种药理活性。Barret等首次报道了乙二醛二缩氨基硫脲(Ⅰ)的抗疟活性。Klayman等研究了缩     

A comparison of the behaviour to ions of the P3 component of the pigeon cone and rat rod electroretinogram

1. Isolated pigeon and rat retinas were incubated in various media and the effect of changing ions on the P III component of the electroretinogram was studied, with particular regard to the influence of calcium on other ions.2. In pigeon, without calcium, reduction of sodium and chloride both reduce P III. This behaviour continues in the presence of calcium but only if the retina has been treated with ouabain. Under these conditions, the effect of calcium is to prevent the appearance of inverted responses.3. Under other conditions, calcium renders the pigeon P III insensitive to change in chloride. Sensitivity is rapidly restored by the use of ouabain, 2,4-DNP, or by cooling.4. Calcium does not alter the linear relationship between sodium and response amplitude.5. In pigeon, increasing potassium increases P III amplitude, though the exact relationship is altered by calcium.6. In the rat retina treated with ouabain, increasing sodium increases P III, and increasing potassium decreases P III. This result is similar to that of Sillman, Ito & Tomita (1969b). If calcium is absent, inverted P IIIs can be obtained.7. If calcium is present in the medium, reducing sodium also reduces rat P III.8. If calcium is reduced below 10(-7)M, then reducing sodium increases P III, and large responses are obtainable from solutions which contain almost no ions. These responses vanish very rapidly if the retina is cooled or treated with ouabain.     

Co-detection and discrimination of six human herpesviruses by multiplex PCR-ELAHA.

BACKGROUND: Herpesviruses are a significant cause of human morbidity. Traditional approaches to the identification of these viruses require infectious or at least antigenic virus. Multiplex PCR (mPCR) is capable of simultaneously amplifying a range of targets from a single preparation of nucleic acids and when combined with a suitable detection assay, it is capable of discriminating each of the amplicons. OBJECTIVES: Several methods have been described in the literature, however, they lack one or more significant design features required to suitably control a routinely applied nucleic acid amplification assay. We aimed to design a multiplex herpesvirus PCR that could co-amplify eight human herpesvirus targets plus an internal control (IC) molecule in a single tube. STUDY DESIGN: Primers were designed to target the DNA polymerase genes of each of the human herpesviruses. Synthetic controls were developed to act as templates for the evaluation of assay sensitivity and specificity and for development of an in-house competitive quantitative PCR. Amplicon was discriminated using a simplified enzyme linked amplicon hybridisation assay (ELAHA). RESULTS AND CONCLUSIONS: For routine diagnostic use we reduced the number of herpesviral targets from 8 to 6 in order to maintain adequate clinical sensitivity. The ELAHA proved more sensitive than agarose gel electrophoresis. Additionally, 36 cytomegalovirus positive patients were examined with an in-house quantitative PCR-ELAHA which was developed to confirm that that the mPCR's co-detection limit of 10(2) copy of synthetic template per millilitre was relevant for use in detecting virus from clinical samples. The mPCR-ELAHA was then applied to the screening of 174 patient specimens resulting in a specificity of 98% and a sensitivity of 93%. This preliminary study demonstrated that the mPCR-ELAHA was a complete approach to the detection of herpesviruses from a range of clinical samples and disease states.     

Immunology of DNA. II. The effect of size and structure of the antigen on the Farr assay.

The Farr assay for the detecton of antibodies to double stranded (ds) DNA is influenced by the DNA preparations used as antigen. To elucidate this the molecular weight of the antigen preparation, contamination with proteins and presence or absence of single stranded (ss) regions were studied with the following conclusions: 1) The degree of DNA binding by antibodies is linearly dependent on the molecular weight of the DNA, provided that this does not exceed 10 X 10(6). 2) Deproteinization of E. coli DNA by chromatography on methylated albumin-kieselguhr(MAK) columns results in lower binding by most sera. 3) ds DNA preparations sometimes contain ss regions which bind antibodies to ss DNA. The difference in behaviour of different ds DNA preparations may be ascribed entirely to these factors and not to differences in antigenic determinants. We have standardized the Farr assay and enhanced its specificity by the use of circular DNA isolated from bacteriophage PM2.     

Prospective Recruitment of Women Receiving Prenatal Care from Diverse Provider Arrangements: A Potential Strategy

Objectives: This study describes the use of a Medicaid managed care list to prospectively recruit into a research project pregnant women receiving care from a variety of providers. Method: A list of women enrolled in Medicaid managed care was used to recruit pregnant African-American and Latina women into a study of prenatal care satisfaction. Due to privacy concerns, the researchers were not able to directly access names from the list. Instead, a managed care contract agency sent recruitment letters to 1009 pregnant African-American and Latina Medicaid recipients. Response rates by ethnicity and several other key variables are calculated. The biases associated with this method of recruiting pregnant women from a variety of providers are discussed. Results: Thirty-five percent of the women contacted returned consent forms and agreed to have researchers approach them; the response rate for African-American women was 43% and for Latinas was 29% (p < 0.0001). Respondents were younger and later in their pregnancies than nonrespondents, but did not differ from them by zip code of residence. The women recruited into the study obtained prenatal care from a diverse group of providers. Conclusions: While the use of a prospectively generated list of pregnant Medicaid recipients to recruit low-income pregnant women into a research study may be associated with some selection bias, the potential cost savings, decreased effort, and diminished recall bias may make their use a feasible sampling alternative, particularly when the researcher desires to recruit women seeking care from a variety of provider arrangements.