Capsule thickness of cataractous lenses with and without exfoliation syndrome

Lens capsule thickness was measured in 105 cataractous lenses with and without exfoliation syndrome. The lenses were removed by intracapsular cryoextraction. Forty lenses (38%) showed exfoliation, while 65 (62%) were exfoliation negative. Thickness values were measured by light microscopy from the central anterior capsule, central posterior capsule and from the equator. The mean thickness values were for the central anterior capsule 8.2 +/- 3.2 mu, for the central posterior capsule 3.2 +/- 1.4 and for the equator 3.9 +/- 1.3. There was no statistical difference between the exfoliation-positive and exfoliation-negative lenses. The capsule thickness varied greatly throughout the present material. The highest value, 22.4 mu, was measured from an exfoliation-negative central anterior lens capsule of a male patient aged 33 years. The lowest value, 0.6 mu, was measured from an exfoliation-positive central posterior capsule of a male patient aged 64 years. The central posterior capsule is the thinnest area of the lens capsule. The findings call for great caution in polishing the posterior capsule during extracapsular cataract surgery. The higher complication rate in eyes with exfoliation syndrome cannot be explained by thinner lens capsules but rather on the more friable zonules.     

Bilateral absolute phakolytic glaucoma. A clinical and ultrasonographic case study

We describe an unusual case of absolute bilateral phakolytic glaucoma. On admission for cataract surgery the 75-year-old patient was found to be totally blind, no light perception in either eye. The ocular tensions were about 75 mmHg in both eyes, corneas hazy, the fundi could not be seen. The swollen lens of the right eye had slightly subluxated downwards. In the left eye the ultrasound showed a luxated swollen lens in the vitreous space. The ultrasound also revealed totally excavated optic discs. This patient had been on the waiting list for 8 months. Information of the stage of the cataracts of patients on the waiting lists for operation is of paramount importance in the prevention of lens induced problems which may lead to irreversible visual deterioration.     

Vascular endothelial growth factor C is required for sprouting of the first lymphatic vessels from embryonic veins

Lymphatic vessels are essential for immune surveillance, tissue fluid homeostasis and fat absorption. Defects in lymphatic vessel formation or function cause lymphedema. Here we show that the vascular endothelial growth factor C (VEGF-C) is required for the initial steps in lymphatic development. In Vegfc-/- mice, endothelial cells commit to the lymphatic lineage but do not sprout to form lymph vessels. Sprouting was rescued by VEGF-C and VEGF-D but not by VEGF, indicating VEGF receptor 3 specificity. The lack of lymphatic vessels resulted in prenatal death due to fluid accumulation in tissues, and Vegfc+/- mice developed cutaneous lymphatic hypoplasia and lymphedema. Our results indicate that VEGF-C is the paracrine factor essential for lymphangiogenesis, and show that both Vegfc alleles are required for normal lymphatic development.     

Weighted expectation maximization reconstruction algorithms with application to gated megavoltage tomography

We propose and investigate weighted expectation maximization (EM) algorithms for image reconstruction in x-ray tomography. The development of the algorithms is motivated by the respiratory-gated megavoltage tomography problem, in which the acquired asymmetric cone-beam projections are limited in number and unevenly sampled over view angle. In these cases, images reconstructed by use of the conventional EM algorithm can contain ring- and streak-like artefacts that are attributable to a combination of data inconsistencies and truncation of the projection data. By use of computer-simulated and clinical gated fan-beam megavoltage projection data, we demonstrate that the proposed weighted EM algorithms effectively mitigate such image artefacts.     

Sleep-wake rhythm in an irregular shift system

Sleep in shift work has been studied extensively in regular shift systems but to a lesser degree in irregular shifts. Our main aim was to examine the sleep-wake rhythm in shift combinations ending with the night or the morning shift in two irregular shift systems. Three weeks' sleep/work shift diary data, collected from 126 randomly selected train drivers and 104 traffic controllers, were used in statistical analyses including a linear mixed model and a generalized linear model for repeated measurements. The results showed that the sleep-wake rhythm was significantly affected by the shift combinations. The main sleep period before the first night shift shortened by about 2 h when the morning shift immediately preceded the night shift as compared with the combination containing at least 36 h of free time before the night shift (reference combination). The main sleep period before the night shift was most curtailed between two night shifts, on average by 2.9 and 3.5 h among the drivers and the controllers, respectively, as compared with the reference combination. Afternoon napping increased when the morning or the day shift immediately preceded the night shift, the odds being 4.35-4.84 in comparison with the reference combination. The main sleep period before the morning shift became 0.5 h shorter when the evening shift preceded the morning shift in comparison with the sleep period after a free day. The risk for dozing off during the shift was associated only with the shift length, increasing by 17 and 35% for each working hour in the morning and the night shift, respectively. The results demonstrate advantageous and disadvantageous shift combinations in relation to sleep and make it possible to improve the ergonomy of irregular shift systems.     

Inhibition of Hedgehog signaling by direct binding of cyclopamine to Smoothened

The steroidal alkaloid cyclopamine has both teratogenic and antitumor activities arising from its ability to specifically block cellular responses to vertebrate Hedgehog signaling. We show here, using photoaffinity and fluorescent derivatives, that this inhibitory effect is mediated by direct binding of cyclopamine to the heptahelical bundle of Smoothened (Smo). Cyclopamine also can reverse the retention of partially misfolded Smo in the endoplasmic reticulum, presumably through binding-mediated effects on protein conformation. These observations reveal the mechanism of cyclopamine's teratogenic and antitumor activities and further suggest a role for small molecules in the physiological regulation of Smo.     

Difference in cytokine production and cell activation between adenoidal lymphocytes and peripheral blood lymphocytes of children with otitis media

We evaluated the immunological potential of adenoidal lymphocytes from children with recurrent otitis media. Interleukin-4 release and CD69 expression were lower in adenoidal lymphocytes than in peripheral blood lymphocytes (PBL). Our results suggest that there may be a difference between the immunological potential of adenoidal lymphocytes and that of PBL in children with otitis.