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PubMed1980

[Water as a vector of infection: waterborne bacteria (author's transl)].

The cholera and typhoid epidemics caused by drinking water were still characterized, at the beginning of the century by a high rate of morbidity and lethality. In addition to these micro-organisms, there are yet other pathogens which find their way into the drinking water. Therefore the pathogens causing infection and for which water can serve as a vector, are shown in a survey and for some of them their survival times in the various types of water are mentioned. The remedial measures which were adopted against the big drinking-water epidemics are represented and the course of the typhoid and the cholera epidemics during the period from 1850 to 1930 is also illustrated. The characteristics of drinking-water epidemics, especially in the case of contamination by S. typhi, are described and supplemented by an illustration. Also the problem of the water field and epidemic field as well as the quantitative spread of pathogens causing infection across all strata of the population are dealt with in detail. Extensive epidemiological data concerning the greatest dysentery drinking-water epidemics caused by Sh. sonnei at Ismaning near Munich give an insight into the genesis of this imported plague. It provides further evidence of the inadequacy into the genesis of this imported plague. It provides further evidence of the inadequacy of our laws which permit hygienic evaluation based on the analysis of samples submitted. No local inspections were carried out and this was ultimately the cause of these epidemics -the health officer in charge put his trust in the good bacteriological findings. Finally the paper deals with the bacteria for which water can also play the role of a vector. Mention is made of the cholera vibrio, vibrio parahaemolyticus, NAG vibrios, enteritis Salmonella in drinking and bathing water, as well as in the waste water-fish pond procedure, erysipelas bacteria, anthrax and field fever, as well as Mycobacterium tuberculosis and atypical mycobacteria.

Bacterial Infections↗
PubMed1994

Molecular characterization of human and bovine endothelin converting enzyme (ECE-1).

A membrane-bound protease activity that specifically converts Big endothelin-1 has been purified from bovine endothelial cells (FBHE). The enzyme was cleaved with trypsin and the peptide sequencing analysis confirmed it to be a zinc chelating metalloprotease containing the typical HEXXH (HELTH) motif. RT-PCR and cDNA screens were employed to isolate the complete cDNAs of the bovine and human enzymes. This human metalloprotease was expressed heterologously in cell culture and oocytes. The catalytic activity of the recombinant enzyme is the same as that determined for the natural enzyme. The data suggest that the characterized enzyme represents the functional human endothelin converting enzyme ECE-1.

Amino Acid Sequence↗
PubMed1993

The viroid: big punch in a small package.

Although viroids consist solely of short lengths of unencapsidated single-stranded circular RNA, they replicate autonomously in plants and cause diseases that are as varied and often as severe as those caused by plant viruses. All this, without ever serving as mRNAs. However, aside from some fascinating glimpses, the mechanisms of viroid pathogenesis remain largely enigmatic.

Base Sequence↗
PubMed1998

Expression of olfactory receptors, G-proteins and AxCAMs during the development and maturation of olfactory sensory neurons in the mouse.

Three mouse olfactory receptors have been cloned and sequenced and were found to be expressed in different zones of the olfactory epithelium. In situ hybridisation (ISH) results showed that each olfactory receptor was expressed at an early stage in development (E12), was not dependent on the maturation of the receptor neurons, and was present long before the onset of odour detection. Cells positive for these same olfactory receptors and the G-protein (Gbeta) were also found in non-neural regions of the nasal epithelium in the earlier stages of development (E12-16). Ncam, and Big-2 expression were, however, restricted to the region of developing olfactory neurons. Ncam expression appeared in advance of the olfactory receptor expression, while Big-2 appeared after olfactory receptor expression and neither were expressed in cells outside the olfactory epithelium. Both showed the highest number of positive cells in the early post-partum period when olfactory detection is functional. Ncam is known to be involved in guidance of the developing olfactory axons and was expressed earlier than any of the olfactory receptors, while Big-2 appears somewhat later (E14) at a time when developing axons reach the olfactory bulb. Moreover the highest periods of expression occur at post-natal day 7 when a proliferation of bulbar glomeruli are observed, suggesting the role of Big-2 to be primarily concerned with synaptogenesis.

Aging↗
PubMed1997

A novel splice variant of the cell adhesion molecule BIG-2 is expressed in the olfactory and vomeronasal neuroepithelia.

We have cloned a mouse cDNA encoding a novel truncated form of the gene BIG-2 from the vomeronasal organ. The related proteins BIG-2 and BIG-1 possess a C-terminal glycosylphosphatidylinositol anchor, six immunoglobulin domains and four fibronectin type III repeats. They are related to certain axonal-associated cell adhesion molecules (AxCAMs) exhibiting most similarity to the TAG-1/F3 subgroup of neural cell adhesion molecules. The cDNA we have identified, termed BIG-2A, appears to represent a novel splice variant of BIG-2 possessing six Ig-like domains, a single fibronectin repeat and lacking the glycosylphosphatidylinositol-anchoring domain (GPI). To determine the expression of this gene, in situ hybridization analysis was performed in adult and developing mice using a riboprobe specific for BIG-2A. Maximum expression was observed in mature sensory cells of the vomeronasal neuroepithelium and a less intense signal was also evident in the olfactory neuroepithelium. These results suggest that alternative splicing of the BIG-2 gene transcript may play an important role in the organization of the vomeronasal and olfactory neuroepithelia.

Alternative Splicing↗
PubMed1996

Distribution of lead, copper and zinc in size-fractionated river bed sediment in two agricultural catchments of southern Ontario, Canada.

Metal (Pb, Cu and Zn) partitioning in six separated sediment size fractions (<8, 8-12, 12-19, 19-31, 31-42, 42-60 microm) of river bed sediment have been analyzed by sequential extraction. The concentrations of some major elements (Si, Al, Ca, Mg, K, Na, Fe, Mn and P), and organic and inorganic C were determined to correlate the elemental composition of the sediment with metal speciation and grain size. Results show that Zn and Pb concentrations increase with decreasing grain size. For Big Creek and Big Otter Creek, respectively, the highest concentrations of Zn (326 and 230 mg kg(-1)) and Pb (158 and 67 mg kg(-1)) were found in the smallest (<8 microm) fraction, whereas the Cu levels (619 and 1281 mg kg(-1)) were most abundant in the second smallest (8-12 microm) fraction. The major accumulative phases for Cu, Zn and Pb were carbonates, Fe/Mn oxides and organic matter, but the relative importance of each phase varied for individual metals and grain sizes. The extraction data show increasing potential bioavailability of metals with decreasing grain size. Estimates of metal yields in the study catchments suggest that over 80% of the metal yield in sediment smaller than 63 microm is associated with solids smaller than 31 microm.

Journal Article↗
PubMed2003

Uses of enthalpy-entropy compensation in protein research.

Cooperative systems of proteins and small molecules form most of biology but are so weakly linked that conventional mass-law formalism requiring exact stoichiometry is inapplicable. The weaknesses cannot be eliminated but using selected families of reactions useful fragmentation of those quantities is often possible. Extra-thermodynamic treatments based on linear-free-energy relationships (LFE) are developed to utilize enthalpy, entropy and volume information not otherwise reliable Linkage systems build around mesophilic proteins are well suited to enforced marriage of linear equations and scaled molecule detail because the ratio of substructure sizes on which folded stability depends is independent of total number of amino-acid residues. Conformational changes in physiological function usually no greater than 0.5 A closely scale to linear thermodynamic changes. The formalisms for use of LFE and compensation relationships are modified to eliminate complications that have previously arisen from incorrect inclusion of the thermal parts of enthalpy and entropy changes in free energy changes. The results are used to remove current confusion about the basis of folded stability in proteins and to minimize the quantitative errors arising from classical treatments of denaturation data. The enthalpy to entropy ratio given by the slope of a compensation plot (its 'compensation temperature') is used to characterize protein construction and function so as to extract machine descriptions of protein linkage systems. In this way the 'fragile' nature of the free-energy surfaces of the myoglobin proteins and the 'strong' character of those surfaces of most other mesophiles can be deduced very simply from the Debye-Waller factors obtained in diffraction studies. The major evolutionary achievement in making proteins big is their crystallike phase behavior. That makes entropy exactly as important as enthalpy so the scalar quantities of small-molecule chemistry can be replaced by the vector quantities that appear necessary to make biology possible.

Entropy↗
PubMed2003

Unified risk analysis of fatigue failure in ductile alloy components during all three stages of fatigue crack evolution process.

Statistical fatigue life of a ductile alloy specimen is traditionally divided into three stages, namely, crack nucleation, small crack growth, and large crack growth. Crack nucleation and small crack growth show a wide variation and hence a big spread on cycles versus crack length graph. Relatively, large crack growth shows a lesser variation. Therefore, different models are fitted to the different stages of the fatigue evolution process, thus treating different stages as different phenomena. With these independent models, it is impossible to predict one phenomenon based on the information available about the other phenomenon. Experimentally, it is easier to carry out crack length measurements of large cracks compared to nucleating cracks and small cracks. Thus, it is easier to collect statistical data for large crack growth compared to the painstaking effort it would take to collect statistical data for crack nucleation and small crack growth. This article presents a fracture mechanics-based stochastic model of fatigue crack growth in ductile alloys that are commonly encountered in mechanical structures and machine components. The model has been validated by Ray (1998) for crack propagation by various statistical fatigue data. Based on the model, this article proposes a technique to predict statistical information of fatigue crack nucleation and small crack growth properties that uses the statistical properties of large crack growth under constant amplitude stress excitation. The statistical properties of large crack growth under constant amplitude stress excitation can be obtained via experiments.

Journal Article↗
PubMed1997

How big is a Gabor patch, and why should we care?

We propose a two-parameter model for the perceived size (spatial extent) of a Gaussian-windowed, drifting sinusoidal luminance pattern (a Gabor patch) based on the simple assumption that perceived size is determined by detection threshold for the sinusoidal carrier. Psychophysical measures of perceived size vary with peak contrast, Gaussian standard deviation, and carrier spatial frequency in a manner predicted by the model. At suprathreshold peak contrasts Gabor perceived size is relatively unaffected by systemic noise but varies in a manner that is consistent with the influence of local contrast gain control. However, at and near threshold, systemic noise plays a major role in determining perceived size. The data and the model indicate that measures of contrast threshold using Gaussian-windowed stimuli (or any other nonflat contrast window) are determined not just by contrast response of the neurons activated by the stimulus but also by integration of that activation over a noisy, contrast-dependent extent of the stimulus in space and time. Thus, when we wish to measure precisely the influence of spatial and temporal integration on threshold, we cannot do so by combining contrast threshold measures with Gaussian-windowed stimuli.

Contrast Sensitivity↗
PubMed2002

An experimental and theoretical study on the dissolution of mural fibrin clots by tissue-type plasminogen activator.

During thrombolytic therapy and after recanalization is achieved, reduction in the volume of mural thrombi is desirable. Mural thrombi are known to contribute to rethrombosis and reocclusion. The lysis rate of mural thrombi has been demonstrated to increase with fluid flow in different experimental models, but the mechanisms responsible are unknown. An experimental and a theoretical study were developed to determine the contribution of outer convective transport to the lysis of mural fibrin clots. Normal human plasma containing recombinant tissue-type plasminogen activator (tPA; 0.5 microg/mL) was (re)perfused over mural fibrin clots with fluorescently labeled fibrin at low arterial, arterial, or higher wall shear stresses (4, 18, or 41 dyn/cm(2), respectively) and lysis was monitored in real time. Flow accelerated lysis, but significantly only at the highest shear stress: The average lysis front velocity was 3 x 10(-5) cm/s at 41 dyn/cm(2) vs. almost half of that at the lower shear stresses. Confocal microscopy showed fibrin fibers dissolving only in a narrow region close to the surface when permeation velocity was predicted to be low. A heterogeneous transport-reaction finite element model was used to describe mural fibrinolysis. After scaling the effects of outer and inner convection, inner diffusion, and chemical reactions, a simplified inner diffusion/reaction model was used. Correlation to fibrin lysis data in purified systems dictated higher rates of plasmin(ogen) and tPA adsorption onto fibrin and a decreased catalytic rate of plasmin-mediated fibrin degradation, compared with published parameters. At each shear stress, the model predicted a temporal pattern of lysis of mural fibrin (similar to that observed experimentally), and protease accumulation in a narrow fibrin region and significant lysis inhibition by plasma alpha(2)-antiplasmin (according to the literature). Increasing outer convection accelerated mural fibrinolysis, but the model did not predict the big increase in lysis rate at the highest shear stress. At higher than arterial flows, additional mechanisms not accounted for in the current model, such as fibrin collapse at the fibrin front, may regulate the lysis of mural clots and determine the outcome of thrombolytic therapy.

Blood Flow Velocity↗
PubMedDate not supplied

[Mental retardation and psychiatric pathology. Statistical investigation and follow-up].

The Authors describe the organization and aims of the rehabilitation institute "G. Ferrero" of Alba, Cuneo district, Italy. Afterwards they present, analyse and compare 34 items regarding patients over 14 years of age that were present on the 30 November 1978 and 1988. The most important data are: 1) a large rise in average age and stay at the institute; 2) a similar rise in the mental retardation level; 3) the lack of link between handicap level and possibility for the subject to go back to the original family; 4) a considerable increase in the subjects with psychosis or cerebropathia; 5) the poor prognosis for psychotic subjects, that are affected 10 years after and almost never succeed in going back to their original family or in finding a job; 6) big changes that changing types of patients produced in the institute's aims and in treatment, with partial renunciation to rehabilitation and development of nursing and ergotherapy.

Adolescent↗
PubMed2002

[Evaluation of satisfaction of patients hospitalized at the Kairouan Hospital].

The patients' satisfaction studies are more and more utilized to underline the health centers' deficiencies and consequently set improvement action plans. Our survey aims to measure inpatients' satisfaction in its different dimensions. A survey centered around a transversal inquiry has been conducted during a period going from February to April 2000 and reached a total number of 817 patients hospitalized in six service units at kairouan hospital. The data has been gathered by structured interviews led by a previously trained social worker. The investigation tool was a standardized questionnaire prepared by a group of experts from WHO in the Oriental Mediterranean region. The main results are as follow: High satisfaction level concerning the global evaluation of the hospital service units was recorded (score = 70%). The patient who are more satisfied are those who have the feeling that their health situation has considerably improved, and who will probably recommend this hospital to their surroundings. Big proportion of the patients (77%) was expecting better services. The main reason behind their unhappiness is the information emanated whether from the nurses or the doctors, the comfort and the cleanness of waiting room, linen, room comfort, food and the emergency. These results showed that the quality of care improvements priorities, according to patient expectations are especially in relation with the quality of information, the relational aspects and the hospital stay conditions.

Adult↗
PubMedDate not supplied

cDNA cloning, tissue distribution, and subcellular localization of horseshoe crab big defensin.

A full-length cDNA for horseshoe crab big defensin with a strong antimicrobial activity was obtained from a hemocyte cDNA library. The open reading frame of the cDNA coded for an NH2-terminal signal sequence followed by a propeptide and the mature big defensin. The propeptide is linked to the mature protein through an -Arg-X-Lys/Arg-Arg- motif, the processing site for Kex2-like proteases. Northern blot analysis revealed that big defensin is expressed in all the tissues tested, suggesting that big defensin plays an important role not only in hemocytes but also in other tissues for host defense. The subcellular localization, determined by immunocytochemistry at ultrastructural level, confirmed the previous findings obtained by biochemical analysis that big defensin locates in both small and large granules in hemocytes. Big defensin is the first example to demonstrate the existence of broad tissue distribution in horseshoe crab.

Amino Acid Sequence↗
PubMed2007

Some data-driven reflections on priorities in AIDS network research.

Risk networks can transmit HIV or other infections; social networks can transmit social influence and thus help shape norms and behaviors. This primarily-theoretical paper starts with a review of network concepts, and then presents data from a New York network study to study patterns of sexual and injection linkages among IDUs and other drug users and nonusers, men who have sex with men, women who have sex with women, other men and other women in a high-risk community and the distribution of HIV, sex at group sex events, and health intravention behaviors in this network. It then discusses how risk network microstructures might influence HIV epidemics and urban vulnerability to epidemics; what social and other forces (such as "Big Events" like wars or ecological disasters) might shape networks and their associated norms, intraventions, practices and behaviors; and how network theory and research have and may continue to contribute to developing interventions against HIV epidemics.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Mathematical modelling of digesta passage rate, mean retention time and in vivo apparent digestibility of two different lengths of hay and big-bale grass silage in ponies.

Welsh-cross pony geldings (about 300 kg live weight) were used in a 4x4 Latin square experiment to determine the rate of passage and apparent digestibility of unchopped big-bale grass silage (BBL), chopped big-bale grass silage (BBS), unchopped grass hay (HL) and chopped grass hay (HS) offered at approximately 15 g/kg live weight per d. On day 1 of collection weeks, ponies were fed 85 g ytterbium chloride hexahydrate-marked feed 1.5 h after the morning meal. Total faecal collections commenced 8 h later and continued for 168 h. Apparent digestibilities of feed DM, organic matter (OM), crude protein (CP, Nx6.25), acid-detergent fibre (ADF) and neutral-detergent fibre (NDF) were also determined. Faecal excretion data were subjected to the models of Pond et al. (1988) and digesta mean retention time (MRT) calculated from these models and using the algebraic method of Thielmans et al. (1978). Silage had significantly (P<0.05) higher digestibilities of DM, OM, CP, ADF and NDF than hay; however, chop length had no effect. All the models of Pond et al. (1988) accurately described (R(2)>0.8) the pattern of faecal marker excretion. MRT of BBL (29.0 h)>BBS(27 h)>HS and HL (26 h). Compartmental analysis using the G3 model of Pond et al. (1988) showed BBL and HS diets had longer MRT in the time-dependent compartment, whereas BBS and HL had longer MRT in the time-independent compartment. Results from this experiment indicate that BBL and BBS are readily accepted and digested by ponies. While Yb is a successful external marker for determining total tract MRT and for modelling faecal excretion curves in horses, the results did not allow any definite conclusions to be drawn on digesta MRT within the different compartments of the equid gut.

Animal Feed↗
PubMed2004

Modeling the population dynamics of Culex quinquefasciatus (Diptera: Culicidae), along an elevational gradient in Hawaii.

We present a population model to understand the effects of temperature and rainfall on the population dynamics of the southern house mosquito, Culex quinquefasciatus Say, along an elevational gradient in Hawaii. We use a novel approach to model the effects of temperature on population growth by dynamically incorporating developmental rate into the transition matrix, by using physiological ages of immatures instead of chronological age or stages. We also model the effects of rainfall on survival of immatures as the cumulative number of days below a certain rain threshold. Finally, we incorporate density dependence into the model as competition between immatures within breeding sites. Our model predicts the upper altitudinal distributions of Cx. quinquefasciatus on the Big Island of Hawaii for self-sustaining mosquito and migrating summer sink populations at 1,475 and 1,715 m above sea level, respectively. Our model predicts that mosquitoes at lower elevations can grow under a broader range of rainfall parameters than middle and high elevation populations. Density dependence in conjunction with the seasonal forcing imposed by temperature and rain creates cycles in the dynamics of the population that peak in the summer and early fall. The model provides a reasonable fit to the available data on mosquito abundance for the east side of Mauna Loa, Hawaii. The predictions of our model indicate the importance of abiotic conditions on mosquito dynamics and have important implications for the management of diseases transmitted by Cx. quinquefasciatus in Hawaii and elsewhere.

Altitude↗
PubMed2004

Virtual reality and psychotherapy.

Virtual Reality (VR) is a new technology consisting on a graphic environment in which the user, not only has the feeling of being physically present in a virtual world, but he/she can interact with it. The first VR workstations were designed for big companies in order to create environments that simulate certain situations to train professionals. However, at this moment a great expansion of this technology is taking place in several fields, including the area of health. Especially interesting for us is the use of VR as a therapeutic tool in the treatment of psychological disorders. Compared to the traditional treatments, VR has many advantages (e.g., it is a protected environment for the patient, he/she can re-experience many times the feared situation, etc.). There are already data on the effectiveness of this technology in the treatment of different psychological disorders; here anxiety disorders, eating disorders and sexual disorders are reviewed. Finally, this chapter ends with some words about the limitations of VR and future perspectives.

Humans↗
PubMed1995

Big deal. Can United HealthCare make a silk purse out of a sow's ear?

On the surface, United HealthCare Corp.'s purchase of The MetraHealth Cos. two months ago looks like a great deal. But United's grand strategy is fraught with obstacles, and the move seems sure to heat up the competition and consolidation taking place in health care coverage.

Antitrust Laws↗