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A new test of Eustachian tube function with otoadmittance meter: tubotympanometry.

A new method for testing Eustachian tube function using an otoadmittance meter (Tubotympanometry) is reported. The otoadmittance meter is set for the aural reflex test, namely in the position of Y-T- recording. The patient is asked to carry out deep breathing. Valsalva's maneuvre, normal breathing, and swallowing in succession. In normal 40 ears, three types of the tubotympanogram were classified. In type A, observed in 32 ears, the graph shows no changes during deep breathing, a sudden downward deflection with Valsalva's maneuvre, a return to a level after the maneuvre and on repeated swallowing the graph returns to the initial level in stepwise. In type B, observed in 5 ears, the graph returns to the initial level directly after Valsalva's maneuvre without swallowing. This indicates a slightly patent tube, even though in the normal range. Type C was observed in 3 ears of patients who failed to perform Valsalva's maneuvre correctly. In the case of a patent tube, the graph shows a remarkable fluctuation synchronizing with inspiration and expiration. In the case of an occluded tube, the graph shows slower recovery after Valsalva's maneuvre and no complete return to the initial level even after repeated swallowing. In another case of occluded tube, the graph was deflected upward by Valsalva's maneuvre and showed no change on deglutition. The greatest advantage of this test is the simplicity of the equipment and of the test procedure.

Acoustic Impedance Tests↗

[Acute sensorineural hearing loss at the Otorhinolaryngology Department of the General Hospital in Subotica 1991-1996].

INTRODUCTION: Sudden sensorineural hearing loss is an acute hearing loss of a perceptive type, of unknown etiology, in most cases one-sided, or, a every sudden sensorineural deafness that occurs in the period of three days or less. Modern scientific literature points to three possible etiological factors: viral cochleitis, vascular lesion of the labyrinth and unrecognized rupture of the membranous labyrinth. The therapy for this disease is extremely various. There are dozens of reported different (or similar) healing protocols, including vasodilators, Hydroxyethyl starch, low molecular dextran, diuretics, defibrinogenation, fibrmolytic therapy, steroids, prostacyclin, oxygen therapy, hyperbaric oxygen therapy, vitamins, etc. The aim of the study was to recapitulate in brief modern views of etiology and therapy of the sudden sensorineural hearing loss, to analyze cases of this illness within the period of 1991-1996 in our Otorhinolaryngology Department and to compare these data with the same or similar data of other authors. MATERIAL AND METHODS: In this study, medical records of patients admitted in the period of 1991-1996 in the Otorhinolaryngology Department of the Health Center in Subotica with a diagnosis of sudden sensorineural hearing loss were used. There were 53 patients with this diagnosis. All patients were treated in the hospital with infusions of rheoactive drugs. During the diagnostic procedure, all patients underwent a complete clinical otorhinolaryngologic examination, detailed anamnesis was taken, acoustic impedance tests (tympanometry) and tonal liminal audiometry were performed. Routine blood test was made (including complete blood picture, sedimentation rate, blood sugar) and a complete urine examination. Sometimes we demanded x-ray of the temporal bones (Schnller and Stenwers). A short increment sensitivity index (SISI) test and Carhart test were also made, if necessary. Function of the vestibular system was tested in cases when the vestibular symptoms were more strongly expressed. This test was made after passing an acute attack of vertiginous symptoms. Control audiometry was made on the seventh and on the fourteenth day after admission. This therapy consisted of an infusion of physiologic solution (NaCl) 250 or 500 ml twice daily to which 300 mg xanthinol nicotinate ampulla, paracetam 1 g ampulla, dipyridamole 10 mg ampulla and C-vitamin 10% 500 mg ampulla were applied. The number of paracetam and xanthinol nicotinate ampullas was raised on the 14/day, and then it fell to the starting value. The therapy lasted 17 days. Patients were given multivitamine peroral therapy, tranquilizers and diet without coffee, smoking and allergenic food. RESULTS AND DISCUSSION: The study included 53 patients, 27 (50.94%) female and 26 (49.06%) males (Graph 1). Their age (Graph 2) ranged between 16-71 years. The biggest group of patients was between 40-49 (39.62%) years of age. Distribution per year (Graph 3) shows that the incidence of the acute sensorineural hearing loss differs from the findings of other authors, especially in the period of 1991-1994, due to very few cases. Connection of this illness with seasons is shown in Graph 4. We had most cases during summer time (August, 16.98%). There is a mild rise in winter (December, 13.21%). The degree of the hearing loss in decibels is shown in the Graph 5. Most of the patients (75.47%) had mild or severely damaged hearing (40-85 dB). Period of the deafness before patients were admitted to the hospital, is shown in Graph 7. Most of them came in the first seven days after they experienced acute deafness (52.83%). Symptomatology of the persons with acute hearing loss is shown in Table 1. All of them had the feeling of deafness, and 50.94% also had tinnitus. Table 2 shows that only two patients had a pathologic finding (hypo function) on the vestibular caloric test. 57.14% of patients tested by this method showed a normal function of the vestibular apparatus. The recovery of he

Adolescent↗

[In vivo blood histamine during anesthesia].

Assays of overal histaminaemia were carried out, in 150 patients anaesthetised according to three different techniques, apart from any surgical act. 119 anaesthesias took place without any incident, 33 were disturbed by the appearance of rashes or of bronchospasm. The overall histaminaemia varied according to three types of graphs (a flat graph, an ascending graph, or a descending graph) without it being possible to evoke any relationship between this course and the clinical signs. It seems that the presence of a background predisposing to histamine-liberation is however responsible for greater frequency of the descending graphs, and that the method of administration of the anaesthetic product is a factor which can intervene in the genesis of the phenomena of histamine-liberation during anaesthesia. An interpretation of the variations in the graphs of histaminaemia is attempted by the authors.

Adolescent↗

Good maps are straight.

This paper proposes a simplified approach to the assembly of large physical genome maps. The approach focuses on two key problems: (i) the integration of diverse forms of data from numerous sources, and (ii) the detection and removal of errors and anomalies in the data. The approach simplifies map assembly by dividing it into three phases-overlap, linkage and ordering. In the first phase, all forms of overlap data are integrated into a simple abstract structure, called clusters, where each cluster is a set of mutually-overlapping DNA segments. This phase filters out many questionable overlaps in the mapping data. In the second phase, clusters are linked together into a weighted intersection graph. False links between widely separated regions of the genome show up as crooked, branching structures in the graph. Removing these false links produces graphs that are straight, reflecting the linear structure of chromosomes. From these straight graphs, the third phase constructs a physical map. Graph algorithms and graph visualization play key roles in implementing the approach. At present, the approach is at an early stage of development: it has been tested on real and simulated mapping data, and the results look promising. This paper describes the first two phases of the approach in detail, and reports on our progress to date.

Chromosomes, Human, Pair 7↗

[The importance of time intervals between childbirth and anemia in pregnancy].

UNLABELLED: During pregnancy some parameters have been studied in order to detect anaemia: amount of erythrocytes, haematocrits, haemoglobin and iron in the serum of 100 women-secundiparae. The greater group of pregnant women (68%) decided for the second pregnancy after two years, while the smaller group (32%) after four years at least. All parameters related to anaemia were present in the groups of shorter time intervals between births. Thus, in the first trimester anaemia was detected in 13.3% of pregnant patients, while only 7.1% in those with a longer interval between deliveries. In the second trimester 33.3% of pregnant women with shorter time intervals suffered from anaemia, and 14.3% of those with a longer interval. The difference is also significant in the third trimester. Namely, 50% of pregnant patients with a shorter interval were anaemic, in comparison to 21.4% of women with a longer interval between deliveries. INTRODUCTION: Anaemia is one of the most frequent illnesses in pregnant patients. The authors found different percentages of its presence in the range from 21 to 80 percent. Sideropenic anaemia is the most common in pregnancy. As Iron is being consumed and lost during delivery, it takes time for its restitution. Therefore Dazabarova advises another childbirth after three years. PURPOSE: Pregnancy and delivery exhaust the organism. It takes time for the recovery and a new pregnancy. Therefore, the purpose of this paper was to examine in what way the time-interval may affect anaemia. METHOD: This paper covers 100 randomized secondiparae. Laboratory examinations were carried out three times during pregnancy, in each trimester separately. The results are shown on the graph so that the difference and importance of the time-interval between deliveries regarding anaemia in pregnant patients, can be noticed. RESULTS: Pregnant women with a two-year interval between deliveries showed anaemia to a greater extent during pregnancy (Graph 1). This was confirmed by tests and was statistically significant (chi 2 = 14.275 and p < 0.001). In women with an interval of four years between deliveries, changes in number of erythrocytes were not statistically significant (chi 2 = 1.167 and p > 0.05). Thus, the difference among the analyzed groups was significant in all trimesters of pregnancy. The results of haematocrits are presented in Graph 2. The difference between the results of greater presence of anaemia in women with shorter time-interval between pregnancies may be statistically significant in the first and second trimesters. In the third trimester, however, the difference still existed, although it was not statistically significant. The results of haemoglobin indicating anaemia (Graph 3) were found in a greater number as pregnancy progressed in women with shorter time-interval between deliveries. This was statistically significant (chi 2 = 15.600 and p < 0.001). In women with greater time-interval between deliveries, a slight increase in haemoglobin was detected, indicating anaemia (chi 2 = 5.918 and p < 0.05). Iron concentrations in the serum indicating anaemia (Graph 4) were constantly decreasing during pregnancy (chi 2 = 7.251 and p < 0.01) in patients with shorter intervals between deliveries, whereas in women with greater time-intervals no significant changes were found (chi 2 = 1.838 and p > 0.05). In Graph 5 the prevalence of anaemia is presented according to the examined parameters. Anaemia was greater in a far larger number of women with shorter intervals between deliveries. This difference is at the limit of statistical significance in the first trimester, tending to become statistically highly significant in the second and third trimesters. DISCUSSION: Frequent pregnancies are one of the causes of anaemia. Namely, they are more often detected in multiparae with shorter time-intervals between deliveries. Our study has confirmed that pregnancy causes haemotopoietic changes (ABSTRACT TRUNCATED).

Anemia↗

An algorithm for constructing local regions in a phylogenetic network.

The groupings of taxa in a phylogenetic tree cannot represent all the conflicting signals that usually occur among site patterns in aligned homologous genetic sequences. Hence a tree-building program must compromise by reporting a subset of the patterns, using some discriminatory criterion. Thus, in the worst case, out of possibly a large number of equally good trees, only an arbitrarily chosen tree might be reported by the tree-building program as "The Tree." This tree might then be used as a basis for phylogenetic conclusions. One strategy to represent conflicting patterns in the data is to construct a network. The Buneman graph is a theoretically very attractive example of such a network. In particular, a characterization for when this network will be a tree is known. Also the Buneman graph contains each of the most parsimonious trees indicated by the data. In this paper we describe a new method for constructing the Buneman graph that can be used for a generalization of Hadamard conjugation to networks. This new method differs from previous methods by allowing us to focus on local regions of the graph without having to first construct the full graph. The construction is illustrated by an example.

Algorithms↗

Patient preferences: survival vs quality-of-life considerations.

OBJECTIVE: To assess whether patients can weigh risk comparisons involving mortality and quality of life in an understandable manner based on their willingness to accept risks of complications. DESIGN: Cross-sectional survey of patients. SETTING: University-based Department of Veterans Affairs Medical Center. PARTICIPANTS: 230 men patients seen in a general medicine clinic. MEASUREMENTS: Two survival graphs were used. Each graph contained survival curves for two alternative unidentified treatments for an unidentified medical condition. Graph 2 contained one curve that had a life expectancy that was 14% higher than the life expectancy of the corresponding curve in graph 1. Respondents were randomly assigned one of the two graphs and were asked to indicate which treatment they preferred and what risk of a change in their quality of life (urinary incontinence or importance) they were willing to accept to achieve longer survival. Patients were also asked whether they had a history of urinary incontinence or impotence. RESULTS AND CONCLUSIONS: Patients tended to be unwilling to accept worse quality of life to achieve increased survival over time. For both curve comparisons, significantly more (p < 0.01) patients accepted a treatment associated with higher mortality to avoid a 100% chance of incontinence than to avoid a 100% chance of impotence. Of the 75% (172/230) of patients reporting willingness to accept risk of either urinary incontinence or total impotence or both, 62% reported having at least some symptoms related to urinary incontinence or impotence. Of the 58 patients not willing to accept the complication risks, only 11% reported a history of urinary incontinence or impotence. The results show that patients are able to make distinctions about severity of morbidity, men are less willing to accept the risk of urinary incontinence than that of total impotence, and men patients who are symptomatic with urinary incontinence or impotence are more willing to accept the risks of treatment than are asymptomatic patients.

Aged↗

An algorithm for a decomposition of weighted digraphs: with applications to life cycle analysis in ecology.

In the analysis of organism life cycles in ecology, comparisons of life cycles between species or between different types of life cycles within species are frequently conducted. In matrix population models, partitioning of the elasticity matrix is used to quantify the separate contributions of different life cycles to the population growth rate. Such partition is equivalent to a decomposition of the life cycle graph of the population. A graph theoretic spanning tree method to carry out the decomposition was formalized by Wardle [Ecology 79(7), 2539-2549 (1998)]. However there are difficulties in realizing a suitable decomposition for complex life histories using the spanning-tree method. One of the problems is the occurrence of life cycles that contain contradictory directions that defy biological interpretation. We propose an algorithmic approach for decomposing a directed, weighted graph. The graph is to be decomposed into two parts. The first part is a set of simple cycles that contain no contradictory directions and that consist of edges of equal weight. The second part of the decomposition is a subgraph in which no such simple cycles are obtainable. When applied to life cycle analysis in ecology, the proposed method will guarantee a complete decomposition of the life cycle graph into individual life cycles containing no contradictory directions.

Algorithms↗

A method to determine which nutrient is limiting for plant growth in estuarine waters--at any salinity.

A method, utilising overlaid graphs for nutrients vs salinity, was developed in order to determine which nutrient is limiting for plant growth in estuarine waters-at any salinity. Dissolved inorganic nitrogen (DIN=NO(3)(-)+NO(2)(-)+NH(4)(+)) and o-phosphate (PO(4)(-)) are the main forms of N and P that are readily bio-available for plant growth in waters and these have a Redfield atomic ratio of N:P=16:1 (i.e. aquatic plants absorb N and P in the average ratio of 16 atoms of N to 1 atom of P). Graphs are prepared for (i) DIN vs salinity and (ii) o-phosphate vs salinity with the vertical scales for DIN and o-phosphate set at a ratio of N:P=16:1; when these graphs are overlaid on each other then the lowermost trendline denotes the limiting nutrient for plant/algal growth-at any salinity. The graphs also indicate the extent by which one or other of the nutrients is limiting--at any salinity. Furthermore, if there is a transition from P to N limitation somewhere along the salinity gradient, then this occurs at the salinity where the trendlines intersect. The concept was applied to three estuaries in the southeast of Ireland and the results show that, in all of these circumstances, P is the limiting nutrient throughout--except for the higher salinities (i.e. salinities 30 per thousand), where either (i) N and P may become equally limiting at salinity approximately 35 per thousand or (ii) N may become limiting at salinity 30 per thousand. Overlaid nutrients vs salinity graphs were also used to demonstrate that, in the estuaries in southeast Ireland, carbon (as dissolved inorganic carbon, DIC=CO(2)+H(2)CO(3)+HCO(3)(-)+CO(3)(2-)) is not the limiting nutrient--at any salinity.

Carbon↗

Schizophrenic speech as a disordered trajectory in a collapsed cognitive "Small-World".

New theoretical instruments, as goal-directed neural networks models and geometric representations based on semantic graphs, open new approaches for our understanding of the schizophrenic speech. The neuropathologic disorders of the schizophrenia can be simulated using neural models, and these models can eventually explain the origin of goal confusion and incoherence in the schizophrenic discourse trajectory. Moreover, these models are useful to evaluate the different hypothesis about the pathogenic mechanisms of the disease. At the same time, a geometric representation of the trajectory of the speech can be obtained from real data. Our conjecture is that a context-dependent graph can be constructed in order to explore if, when the disease became more severe, a transition from a quasi ordered graph to a nearly completely random graph occurs. Plausibly, there exists a wide region where the graph has the properties of a "small-world". This kind of analyses could be potentially carried out using data coming from the spontaneous speech of schizophrenic patients, and can help to evaluate the progress of the disease. At the same time, these geometrical representations could help to evaluate the effect of treatments.

Attitude↗

On analytical approaches to epidemics on networks.

One way to describe the spread of an infection on a network is by approximating the network by a random graph. However, the usual way of constructing a random graph does not give any control over the number of triangles in the graph, while these triangles will naturally arise in many networks (e.g. in social networks). In this paper, random graphs with a given degree distribution and a given expected number of triangles are constructed. By using these random graphs we analyze the spread of two types of infection on a network: infections with a fixed infectious period and infections for which an infective individual will infect all of its susceptible neighbors or none. These two types of infection can be used to give upper and lower bounds for R(0), the probability of extinction and other measures of dynamics of infections with more general infectious periods.

Communicable Diseases↗

Schematic methods for probabilistic enzyme kinetics.

The theory of steady-state enzyme processes which avoids using the mass action law of chemical kinetics and consistently describes catalytic mechanisms by probabilistic concepts has recently been proposed (Mazur, 1991, J. theor. Biol. 148, 229-242). To facilitate the analysis of complex reaction graphs by this theory the possibility of constructing schematic rules similar to those used in classical kinetics is studied. It is found that due to the similarity of algebraic procedures the popular method of King & Altman can be applied in probabilistic kinetics in addition to the earlier proposed rule based on enumeration of cycles of the reaction graph. This similarity also allows one to adapt many other shortcut methods of classical kinetics for probabilistic reaction graphs. The paper considers separately the possibility of transforming reaction mechanisms so that the initial graph is replaced by a simpler but equivalent one. It is shown that there are few cases when a group of states can be replaced by one united state, with earlier known rules such as the rule of Cha for equilibrium stages being particular cases of a more general procedure. In addition a novel method is proposed which performs step-by-step reduction of any reaction graph. All the new methods can be adapted for traditional kinetics as well. The results obtained demonstrate that many schematic rules of classical kinetics are of probabilistic origin.

Enzymes↗

Effect of the compression ratio on properties of lung surfactant (bovine lipid extract surfactant) films.

Using axisymmetric drop shape analysis (ADSA) and a captive bubble technique, the properties of lung surfactant (BLES) films under different compression ratios (i.e. the ratio of maximum to minimum surface area of the bubble) were investigated. In particular, the effect of the compression ratio of the films on the shape of the volume area surface tension-time (VAST) graphs and on the shape of the surface tension relative area (gamma-A ) graphs was examined at the air-liquid interface. Under relatively low compression ratios of the films, the VAST and gamma-A graphs indicate that the cycling is reversible (i.e. the gamma-A graphs are identical for expansion and compression). When the compression ratio of the films increases, failure tends to occur when the surface film can not support the increasing surface pressure, causing a hysteresis loop in the gamma-A graph. It was also found that low surface tension (i.e. below 5 mJ/m2) at the interface could be attained with a 30% compression ratio and collapse of the films always occurs near or below 1 mJ/m2.

Adsorption↗

Computing wiener-type indices for virtual combinatorial libraries generated from heteroatom-containing building blocks.

The expensive and time-consuming process of drug lead discovery is significantly accelerated by efficiently screening molecular libraries with a high structural diversity and selecting subsets of molecules according to their similarity toward specific collections of active compounds. To characterize the molecular similarity/diversity or to quantify the drug-like character of compounds the process of screening virtual and synthetic combinatorial libraries uses various classes of structural descriptors, such as structure keys, fingerprints, graph invariants, and various topological indices computed from atomic connectivities or graph distances. In this paper we present efficient algorithms for the computation of several distance-based topological indices of a molecular graph from the distance invariants of its subgraphs. The procedures utilize vertex- and edge-weighted molecular graphs representing organic compounds containing heteroatoms and multiple bonds. These equations offer an effective way to compute for weighted molecular graphs the Wiener index, even/odd Wiener index, and resistance-distance index. The proposed algorithms are especially efficient in computing distance-based structural descriptors in combinatorial libraries without actually generating the compounds, because only distance-based indices of the building blocks are needed to generate the topological indices of any compound assembled from the building blocks.

Journal Article↗

On the structure of protein-protein interaction networks.

We present a simple model for the underlying structure of protein-protein pairwise interaction graphs that is based on the way in which proteins attach to each other in experiments such as yeast two-hybrid assays. We show that data on the interactions of human proteins lend support to this model. The frequency of the number of connections per protein under this model does not follow a power law, in contrast to the reported behaviour of data from large-scale yeast two-hybrid screens of yeast protein-protein interactions. Sampling sub-graphs from the underlying graphs generated with our model, in a way analogous to the sampling performed in large-scale yeast two-hybrid searches, gives degree distributions that differ subtly from the power law and that fit the observed data better than the power law itself. Our results show that the observation of approximate power law behaviour in a sampled sub-graph does not imply that the underlying graph follows a power law.

Models, Theoretical↗

Synchronization in power-law networks.

We consider realistic power-law graphs, for which the power-law holds only for a certain range of degrees. We show that synchronizability of such networks depends on the expected average and expected maximum degree. In particular, we find that networks with realistic power-law graphs are less synchronizable than classical random networks. Finally, we consider hybrid graphs, which consist of two parts: a global graph and a local graph. We show that hybrid networks, for which the number of global edges is proportional to the number of total edges, almost surely synchronize.

Algorithms↗

Detecting conserved interaction patterns in biological networks.

Molecular interaction data plays an important role in understanding biological processes at a modular level by providing a framework for understanding cellular organization, functional hierarchy, and evolutionary conservation. As the quality and quantity of network and interaction data increases rapidly, the problem of effectively analyzing this data becomes significant. Graph theoretic formalisms, commonly used for these analysis tasks, often lead to computationally hard problems due to their relation to subgraph isomorphism. This paper presents an innovative new algorithm, MULE, for detecting frequently occurring patterns and modules in biological networks. Using an innovative graph simplification technique based on ortholog contraction, which is ideally suited to biological networks, our algorithm renders these problems computationally tractable and scalable to large numbers of networks. We show, experimentally, that our algorithm can extract frequently occurring patterns in metabolic pathways and protein interaction networks from the KEGG, DIP, and BIND databases within seconds. When compared to existing approaches, our graph simplification technique can be viewed either as a pruning heuristic, or a closely related, but computationally simpler task. When used as a pruning heuristic, we show that our technique reduces effective graph sizes significantly, accelerating existing techniques by several orders of magnitude! Indeed, for most of the test cases, existing techniques could not even be applied without our pruning step. When used as a stand-alone analysis technique, MULE is shown to convey significant biological insights at near-interactive rates. The software, sample input graphs, and detailed results for comprehensive analysis of nine eukaryotic PPI networks are available at www.cs.purdue.edu/homes/koyuturk/mule.

Algorithms↗

A note on algorithms for genotype and allele elimination in complex pedigrees with incomplete genotype data.

Elimination of genotypes or alleles for each individual or meiosis, which are inconsistent with observed genotypes, is a component of various genetic analyses of complex pedigrees. Computational efficiency of the elimination algorithm is critical in some applications such as genotype sampling via descent graph Markov chains. We present an allele elimination algorithm and two genotype elimination algorithms for complex pedigrees with incomplete genotype data. We modify all three algorithms to incorporate inheritance restrictions imposed by a complete or incomplete descent graph such that every inconsistent complete descent graph is detected in any pedigree, and every inconsistent incomplete descent graph is detected in any pedigree without loops with the genotype elimination algorithms. Allele elimination requires less CPU time and memory, but does not always eliminate all inconsistent alleles, even in pedigrees without loops. The first genotype algorithm produces genotype lists for each individual, which are identical to those obtained from the Lange-Goradia algorithm, but exploits the half-sib structure of some populations and reduces CPU time. The second genotype elimination algorithm deletes more inconsistent genotypes in pedigrees with loops and detects more illegal, incomplete descent graphs in such pedigrees.

Adult↗