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PubMedDate not supplied

[Genetics of congenital color vision defects. I. Common types of color blindness].

Normal human colour vision is based on the presence of 3 kinds of cones containing 3 different visual pigments, sensitive to short (blue), middle (green) and long (red) wavelengths. Congenital defects of colour vision are based on handicap or total loss of these pigments' function, usually a result of changes in their coding genes. The common types of colour blindness, referred to red-green axis, are present in about 8% of males and 0.44% of females. 3/4 of them are deuteranopes or deuteranomalous trichromats and 1/4 of them are protanopes or protanomalous trichromats. All of them are inherited in X-linked recessive way. The genes have been already mapped and sequenced. The cause of the great majority of their changes is nonhomologous recombination, which produces a gene deletion or creates the red-green or green-red hybrid genes. The result of that is the production of visual pigment with partly or totally changed spectral sensitivity.

Color Vision Defects↗
PubMedDate not supplied

[Genetics of congenital color vision defects. II. Rare types of color blindness].

Between the rare types of colour blindness, the known best are defects of blue colour vision, which are called tritanopia or trinanomaly (tritanomalous trichromacy). Their incidence is 1 in 500 and they are inherited in autosomal dominant way with incomplete penetrance. The basis of them are mutations of the short (blue) wavelength sensitive visual pigment gene. The gene has been mapped on the chromosome 7 and has already been cloned and sequenced. However, the loci heterogeneity should not be excluded in that condition. Another rare type of colour blindness in blue cone monochromacy. It is based on the cone sensitivity to short (blue) wavelength only. The condition is inherited in X-linked recessive way and it is known, that it can be caused by 2 different mechanisms. The first one--two-step pathway--consists of green cone pigment gene deletion, and point mutation of red cone pigment gene. The second one--one-step pathway--arose by deletion of regulatory sequence of both genes of visual pigments, mapped on the X chromosome. Different types of total and partial achromatopsia are also described. The best known ones are: rod monochromacy, which is inherited in autosomal recessive way and consist of rod vision only, and cone dystrophy, usually inherited in X-linked recessive way.

Chromosome Mapping↗
PubMed1995

[Color-coded duplex ultrasound findings and transcranial color duplex ultrasound findings in patients with acute inner ear disorders--a preliminary observation].

A prospective investigation of 98 patients with acute loss of inner ear function showed that such patients display changes in the pulsatility of the basilar artery; however, the differences can be appreciated only by comparison with control sonograms during the course of the disease. Patients with sudden deafness or sudden loss of equilibrium generally showed unremarkable findings on duplex sonography of the cervical portions of vessels supplying the brain.

Acute Disease↗
PubMed1994

[Comparison of the results of conventional ultrasonography and color doppler analysis in the evaluation of the nature of adnexal tumors. II. Color duplex doppler ultrasonography].

The author evaluates the possibilities of coloured Doppler vaginosonography for prebioptic evaluation of the nature of ovarian tumours. He investigated the site of vascularization of tumours and qualitatively the blood flow by assessing the vascular resistance (PI, RI) and character of the flow velocity curve. The results revealed a statistically significant (p < or = 0.05) trend of central vascularization of malignant tumours. A new parameter with a 100% sensitivity and 89% specificity proved to be the notch at the beginning of the diastolic part of the velocity curve which was not observed in any carcinomas but was present in 89% of benign lesions. The vascular resistance was significantly lower in malignant tumours. The cut off value of malignity of the pulsatility index PI = 0.7 had a 86% sensitivity and 100% specificity. The cut off value of the resistance index RI is 0.6 with a 100% sensitivity and 75% specificity. Comparison of the predictive values of malignity of conventional and coloured duplex ultrasonography revealed that for evaluation of the nature of ovarian tumours coloured duplex sonography with several parameters is more suitable. PI and RI alone can be considered rather as indicators of active growth.

Adult↗
PubMed1994

[Color velocity imaging for diagnosis in kidney transplants. Methods for interpretation of color coding].

Colour velocity imaging is a new technique in the field of colour-coded sonographic flow measurement. It measures blood flow directly by analysing ultrasound pulses' running time and has advantages over colour Doppler systems. Colour velocity imaging's colour code detects changes in arterial blood flow. Therefore it can be used in the diagnosis of kidney allografts in the same way as duplex ultrasound. Using the presented methods of colour interpretation, sensitivity of 66.6-100% and specificity of 72.7-91.7% are attained. Thus colour velocity imaging combines the attributes of duplex ultrasound and colour Doppler ultrasound.

Blood Flow Velocity↗
PubMed1976

[Constancy of color perception in the gray toad (Bufo bufo L.): role of the surrounding background in recognition of stimulus color].

The paper continues the previous study (1) on some aspects of toad colour vision. It deals with signs which allow the visual system of toad to recognize blue stimuli. The behavioural experiments were performed during the breeding season when males exhibited the clasping of stationary blue stimuli. It is shown that in spite of some variety of spectral compositions of light sources males clasp only blue stimuli on white surrounding background. Under fixed illumination on white background males clasp blue stimuli, while on red and/or yellow background they clasp grey stimuli as well. These responses appear explicable if it is assumed that the surrounding background is the main sign of a spectral composition of illumination with "the simultaneous colour contrast" being a part of the constant colour perception mechanism (2).

Animals↗