On the role of calcium diffusion and its rapid buffering in intraflagellar signaling.

We have considered the realistic mechanism of rapid Ca2+ (calcium ion) buffering within the wave of calcium ions progressing along the flagellar axoneme. This buffering is an essential part of the Ca2+ signaling pathway aimed at controlling the bending dynamics of flagella. It is primarily achieved by the mobile region of calmodulin molecules and by stationary calaxin, as well as by the part of calmodulin bound to calcium/calmodulin-dependent kinase II and kinase C. We derived and elaborated a model of Ca2+ diffusion within a signaling wave in the presence of these molecules which rapidly buffer Ca2+. This approach has led to a single nonlinear transport equation for the Ca2+ wave that contains the effects brought about by both as necessary buffers for signaling. The presence of mobile buffer calmodulin gives rise to a transport equation that is not strictly diffusive but also exhibits a sink-like effect. We solved straightforwardly the final transport equation in an analytical framework and obtained the implied function of calcium concentration. The effective diffusion coefficient depends on local Ca2+ concentration. It is plausible that these buffers' presence can impact Ca2+ wave speed and shape, which are essential for decoding Ca2+ signaling in flagella. We present the solution of the transport equation for a few specified cases with physiologically reasonable sets of parameters involved.

Calcium signal transmission by axonemal microtubules as an optimized information pathway in cilia and flagella.

Calcium plays a key role in signal transduction in eukaryotic cells. Besides controlling local functions of cells calcium ions are responsible for the generation of global signals such as waves and spikes. Pulsatile increases of calcium concentrations are generally considered to have a much higher fidelity of information transfer than simple tonic changes, since they are much less prone to noisy fluctuations. In that respect, it was clearly revealed that Ca2+ has very crucial involvement in many signaling pathways in cilia and flagella. We earlier established a model in which axonemal microtubules exhibit the features of nonlinear polyelectrolitic electric transmissions lines for efficient transport of cations, primarily Ca2+. These microtubules guide accumulated "ionic clods" which serve as the pulsatile signals aimed to regulate pertaining motor proteins, dyneins and kinesis. We here consider such Ca2+ signals in axoneme in the context of Shannon's and Fisher's information theories. It appears that the fast drift of these "ionic clouds" represents the optimized calcium signaling for control of "flagellary beats" as well as intraflagellary transport of proteins essential for the construction, elongation and maintenance of eukaryotic cilia and flagella themselves.

Random coincidence and angular correlation corrections in the sum-peak method using Monte Carlo simulations.

The sum-peak method is a technique for measuring the absolute activity of gamma cascade emitting sources with a single gamma spectrometer. The effects of angular correlations and random coincidences, if not taken into account, can significantly reduce the accuracy of the method. However, we show that Monte Carlo simulations can reproduce the spectral data with a sufficient quality to perform the required corrections. In this work, we introduced a novel approach for data corrections for angular correlations and pile-up using Monte Carlo simulations. Furthermore, the new method for forming the count rate equations leads to a new formula for the sum-peak method, including random coincidences of any order.

Calcium signaling modulates the dynamics of cilia and flagella.

To adapt to changing environments cells must signal and signaling requires messengers whose concentration varies with time in space. We here consider the messenger role of calcium ions implicated in regulation of the wave-like bending dynamics of cilia and flagella. The emphasis is on microtubules as polyelectrolytes serving as transmission lines for the flow of Ca2+ signals in the axoneme. This signaling is superimposed with a geometric clutch mechanism for the regulation of flagella bending dynamics and our modeling produces results in agreement with experimental data.

An improved formula for determination of the activity via the sum-peak method.

The sum-peak method principally enables determination of the absolute activity of gamma cascade emitting sources based only on the use of spectral data, without knowledge of the detector efficiencies. However, to achieve better accuracy of the activity results, corrections due to pile-up, accidental coincidences, electronic noise and angular correlations must be introduced into the proposed method. Such corrections usually require the collection of a few gamma spectra and additional extrapolations, thereby further complicating the experimental procedures. In this paper, it is shown that by using pile-up peaks for corrections of accidental coincidences, Monte Carlo techniques for angular correlation, and LLD corrections, the source activity can be measured with accuracy and reproducibility below 1% using only one gamma spectrum, without any additional extrapolations.

[Genetic background of rheumatoid arthritis in connection with a family tree]. / A rheumatoid arthritis genetikai hátteréról egy családfa kapcsán.

Authors present a rare history of a family with accumulation of autoimmune diseases. From eight siblings four had rheumatoid arthritis, one systemic lupus erythematodes, one primary Sjögren syndrome, and one Reiter disease. Interestingly, neither the parents nor the offsprings were affected. Because of the possible genetic background, the authors performed HLA serologic and DNA investigations in nine members of the family. The results showed, in agreement with data from the literature, the accumulation of HLA-DQ7 (DQB1*0301), DR4, B27 and DR6 (DR13) risk factors. This observation confirms, that the clinical and immunogenetic features are different in familiar and sporadic forms of rheumatoid arthritis. Authors summarize the genetic background of rheumatoid arthritis in connection with this family tree.

A simple method for measuring lateral flexion of the dorsolumbar spine.

A simple method for measurement of spinal dorsolumbar lateral flexion is described. Measurements performed on 200 healthy 19-year-old men showed that normal lateral flexion was about 10% of body height. The method which requires only a measuring tape correlates well with that recorded by the more sophisticated inclinometer.

[Diagnostic and treatment possibilities in cochleovestibular syndromes]. / Posibilitati de diagnostic si de tratament în sindroamele cohleovestibulare.

The cases of cochleovestibular syndromes admitted into the O.R.L. ward during one year are statistically processed. 81 cases of hypoacusis of perception and vertiginous syndromes were admitted between January 1 and December 31, 1987. 42 of them were males and 29 females. 31 were pure cochlear syndromes, 32 vestibular syndromes without affecting the cochlea, and 15 were cochleovestibular syndromes. The paper surveys the available ways of investigation, by which a topographic and etiologic diagnosis can be determined, within certain limits and an adequate treatment can be recommended.

[Allergic gastric hemorrhage in a case of milk hypersensitivity]. / Allergische Magenblutung bei einer Uberempfindlichkeit gegen Milch

In a 50-year-old patient who was repeatedly hospitalised on account of melaena and twice operated without finding an ulcer the cause of the haemorrhage was first unknown. In the sixth massive haemorrhage endoscopically was established a haemorrhagic erosive gastritis which underwent a spontaneous retrogression (gastroscopic control). Since the skin test on milk was positive, it was not thought of an allergic gastritis by milk and a provocation test was carried out twice which had a positive result (haemorrhagic erosive gastritis after instillation of milk into the stomach). With the publication of this case the attention shall be turned to the gastric haemorrhage caused by a nutritive allergy as well as to the diagnostic value of the simply producible provocation test.