跳至主要内容

Normal Pressure Hydrocephalus: A Simple Hypothesis

Normal pressure hydrocephalus (NPH) is a brain disorder in which excess cerebrospinal fluid (CSF) accumulates in the brain’s ventricle, while the pressure of the fluid is usually normal. It is usually characterized by abnormal gait, urinary incontinence, and (potentially reversible) dementia. It is most commonly seen in older adults, but it’s not easy to diagnose exactly and to be treated. The usual treatment is surgical installation of a ventriculoperitoneal shunt to drain excess CSF into the lining of the abdomen where the CSF will eventually be absorbed.

To better understand its pathophysiology, in this paper, in combination with many theories that have been published in recent years and the experience of diagnosing and operating on hydrocephalus patients, the authors presented a hypothesis, a model for observable but unexplained facts, but also “progressive focusing”, a qualitative method where some experimental facts were used in an effort to understand a disease that was not fully charted. The hypothesis had evolved during the search for a meaningful explanation to known problems regarding the normal pressure hydrocephalus diagnosis. And the authors mainly introduced the following parts: the ApoE3 theory, head size, arachnoid granulations and the subpial theory.

And the conclusion showed that the pathology regarding CSF absorption lied in the subpial spaces in the basal cisternas and along the great vessels entering the brain. Here the idiopathic NPH was caused by reduced pulse pressure, which was needed to press the CSF into the venules. Here the ApoE3/3 genotype with the largest head percentile seemed to be the most vulnerable. For the acquired type of NPH the disruption of the subpial space reduced the entrance and subsequent resorption of CSF. And the arachnoid granulations played no role in resorption of CSF, but were rather most likely sensory and secretory organs necessary to control intracranial venous pressure.

Article by Gardar Gudmundsson, from Uppsalir Medical Center, Reykjavik, Iceland.

Full access: http://mrw.so/1cs7iB

Image by Finda TopDoc, from Flickr-cc.

评论

此博客中的热门博文

Incorporation of High-Altitude Balloon Experiment in High School Science Classrooms

High-altitude balloon is a balloon, filled usually with helium or hydrogen that ascends into an area called “near space” or stratosphere. The most common type of high-altitude balloons are weather balloons. Other purposes include use as a platform for experiments in the upper atmosphere. Modern balloons generally contain electronic equipment such as radio transmitters, cameras, or satellite navigation systems, such as GPS receivers. The mission of the High-Altitude Balloon Experiment (HABE) is to acquire supporting data, validate enabling technologies, and resolve critical acquisition, tracking, and pointing (ATP) and fire control issues in support of future space-based precision pointing experiments. The use of high-altitude balloons offers a relatively low-cost, low-vibration test platform, a recoverable and reusable payload, worldwide launch capability, and a 'near- space' emulation of the future space systems operational scenarios. More recently, several university...

The Influence of Heated Soil in Crop of “Tamaris” Tomato Plants on the Biological Activity of the Rhizosphere Soil

Tomato is a plant with high heat requirements and sensitive to cold weather and frost. The optimum temperature for the growth of tomato plants is between 21˚C and 27˚C during the day and between 17˚C and 21˚C at night. The soil temperature is also very important for plant growth. The optimum soil temperature for tomato cultivation should be within the range 15˚C - 18˚C. Besides, the proper development of the root system depends on the optimal temperature of the soil. A temperature below 14˚C reduces and inhibits the growth of the root system and encourages the development of fungal and bacterial diseases. In this study, the authors aimed to evaluate the effect of heated soil on the population of bacteria, fungi and nematodes inhabiting the soil of tomato cultivar “Tamaris” growing in peat and coconut substrates. The experiment was carried out in 12 treatments and in 3 replications (one slab was one replication). The soils were tested in two different types of containers: cylinders...

Electron Spin and Proton Spin in the Hydrogen and Hydrogen-Like Atomic Systems

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=52202#.VIj7tMnQrzE Author(s) Stanisław Olszewski * Affiliation(s) Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland . ABSTRACT The mechanical angular momentum and magnetic moment of the electron and proton spin have been calculated semiclassically with the aid of the uncertainty principle for energy and time. The spin effects of both kinds of the elementary particles can be expressed in terms of similar formulae. The quantization of the spin motion has been done on the basis of the old quantum theory. It gives a quantum number n = 1/2 as the index of the spin state acceptable for both the electron and proton ...