Voriconazole in the treatment of fungal osteomyelitis of the orbit in the immunocompromised host

Scedosporium apiospermum is an uncommon cause of fungal infection in the orbit and sinus. Morbidity and mortality rates in immunocompromised patients are high. We review the first case of Scedosporium apiospermum orbito-sinus infection that was successfully treated with the new antifungal agent voriconazole. We highlight the efficacy of this drug, particularly in the treatment of osteomyelitis of the orbit and sinus, which may lead to an improvement in survival rates after Scedosporium infection.     

Errors in determining the direction of the visual axis in the presence of defocus

The visual axis is the ray path from the fixation point to the fovea by way of the nodal points. Such a ray path does not exist in unaccommodated vision when the fixation point does not coincide with the far point of the eye because of induced or natural defocus. Nevertheless an approximation to the visual axis can be obtained by the position of a small pupil close to the cornea for which a bichromatic vernier target appears correctly aligned. When the visual axis is determined, an eye rotation from the visual fixation position must occur, which is reversed upon removing the small pupil. Upon engaging in any experiments for which the visual axis is then used as a reference, there is an error in this reference position. We develop simple paraxial equations to estimate this error. We show that these equations have good accuracy. The error associated with locating the visual axis at the cornea is 0.002 mm per dioptre of defocus, which is small enough to be ignored.     

The role of the osmotic pressure of the blood in the pathogenesis of diabetic changes in the retina

Based on the regularities of circulation mechanics, the authors hypothesize the role of osmotic pressure in the development of diabetic changes in the retina. A mathematical model of tissue fluid movement based on this hypothesis shows that transmural pressure in choriocapillaries is higher than in exchange vessels of the retina, and therefore unidirectional fluid flow from choriocapillaries to these vessels develops. A sharp increase in glucose concentration is paralleled by an increase in osmotic pressure, which, in turn, creates a negative hydraulic pressure in retinal tissue and leads to overstretching of exchange vessels and appearance of microaneurysms. One of pathogenetically based therapeutic effects of laser coagulation in diabetic retinopathy is creation of "fenestrae" in the retinal pigmented epithelium, facilitating tissue fluid movement.     

Regulation of PO2 in the area of the optic papilla of the minipig in hyperoxia

PO2 measurements using a double barrelled recess type microelectrodes were measured in the optic nerve head of miniature pigs in normoxia and hyperoxia. Although periarteriolar PO2 increased markedly during systemic hyperoxia (100% oxygen breathing), the intervascular PO2 remained stable under hyperoxia. These results suggest a regulation of the tissue PO2 of the optic nerve head, as the retina does, at constant values during hyperoxia.     

Role of low and high spatial frequencies in the face-selective responses of neurons in the cortex in the superior temporal sulcus in the monkey

There are neurons in the cortex in the anterior part of the superior temporal sulcus of the macaque monkey with visual responses selective for faces. One aim of the present study was to analyze further the information which leads them to respond, by measuring their responses to parametrically filtered stimuli. The responses of 32 such single neurons were measured to faces which were digitized, lowpass filtered at spatial frequencies of 2, 4, 8,...128 cycles/face, highpass filtered at frequencies of 4, 8,...64 cycles/face, and presented in random sequence using a video framestore. It was found that many of the neurons could respond to blurred images of faces, with a mean frequency at half-maximum amplitude of the neuronal response to the series of lowpass filtered images of faces of 3.3 cycles/face. Almost all the neurons had lowpass cutoff frequencies defined in this way below 8 cycles/face. Many of the neurons could also respond to images of faces in which the only information remaining was a limited amount of high spatial frequency edge information. The mean frequency at half-maximum amplitude of the neuronal response to the series of highpass filtered images of faces was 29.7 cycles/face. Almost all the neurons had highpass cutoff frequencies above 8 cycles/face. Thus, many of the neurons could respond to a lowpass and a highpass filtered image of a face even when these had no spatial frequencies in common. The mean separation between the lowpass and highpass cutoff frequencies was 3.2 octaves. For comparison, face recognition in man can be performed with images which contain only information up to 8 cycles/face, or with highpass filtered images which contain only information down to 8 cycles/face. The response of the neurons was not always a smooth function of frequency, but could decrease as higher frequencies were included in the lowpass filtered images of faces, or as low frequencies were included in the highpass filtered images of faces. This indicates that information in certain frequency bands was able to inhibit these neurons. This was particularly likely to occur for the non-optimal face stimulus for a given neuron, indicating that the selectivity of these neurons to different faces was a combination of the excitation produced by some information in faces and inhibition produced by other.     

白血病抑制因子在眼科神经相关病变发病机制中的作用

白血病抑制因子(leukemia inhibitory factor,LIF)是一种广泛存在于生物体的多功能细胞因子,属于白介素-6家族的一员.在神经系统,LIF参与了众多的生理和病理过程.在眼部,LIF对视神经、神经视网膜及角膜神经等的保护作用逐渐受到重视.在青光眼中,LIF通过激活JAK/STAT3通路发挥对视神经的保护作用,并能在一定程度上刺激轴突再生.在年龄相关性黄斑变性和视网膜色素变性等疾病中,LIF也能通过诱导相关信号通路阻止光感受器细胞死亡,从而有效维持光感受器的功能.另外LIF也能在一定程度上修复角膜神经受损,加速角膜神经再生.LIF在神经保护以及神经损伤后再生过程中的作用日渐突出,可能成为治疗眼科神经病变的新手段.     

Current trends in the determination of the tasks in the surgical treatment of eye wounds

On the grounds of the analysis of literature data on the question of reception and rendering aid different conditions to sufferers from mainly of bullet wounds and on the basis of a many year experience of work at the Clinic of Eye Diseases of the Kirov Higher Army Medical College in this field a conclusion is made about the necessity to review the methods of a so-called surgical treatment of eye wounds. A high technical level of modern diagnostic methods allowing at early terms to rather precisely judge about the volume of the injury as well as very high possibilities of microsurgical technique of operation have created conditions for extending the rational volume of a specialized aid to the sufferers from a (primary) treatment, limited by the most urgent tasks, to an exhaustive one (ideally, conducted at one stage).