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PubMed1992

Presence of viable mould propagules in indoor air in relation to house damp and outdoor air.

The presence of viable mould propagules in indoor air was investigated using the N6-Andersen sampler in combination with DG18-agar, in relation to house damp (characterized with a checklist) and in relation to the presence of moulds in outdoor air. The first part of the study was conducted in 46 houses in the autumn of 1987, the second part in 84 houses in May 1989. Further, in the second part, the results obtained with settlement plates (OPD) were compared with those obtained with the N6-Andersen sampler. The number of CFU/m3 in the indoor and outdoor air varied widely. A large variety of mould genera and species was isolated. Species of Cladosporium, Penicillium and Wallemia predominated. The variability in time was high and the reproducibility of the measurements in terms of CFU/m3 and of species isolated was only moderate. The low predictive value of these measurements limits their use in epidemiological studies of the relationship between exposure to moulds and respiratory symptoms. Overall, the geometric mean concentration was somewhat higher outdoors than indoors. However, the clear differences found between the number of CFU/m3 belonging to different mould species in in- and outdoor air show that the presence of viable mould propagules in indoor air is not simply a reflection of the presence of moulds in outdoor air. The presence of moulds in indoor air was only weakly related to house damp as characterized by the checklist. High, statistically significant correlations were found between the CFU yield obtained with the OPD and the CFU/m3 yield obtained with the N6-Andersen sampler.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1991

The use of 4-diphenylacetoxy-N-(2-chloroethyl)-piperidine (4-DAMP mustard) for estimating the apparent affinities of some agonists acting at muscarinic receptors in guinea-pig ileum.

1. 4-Diphenylacetoxy-N-(2-chloroethyl)-piperidine (4-DAMP mustard), which is known to block muscarinic M3 receptors in preference to muscarinic M2 receptors, was used to estimate the apparent affinity constants of some agonists acting at muscarinic receptors in guinea-pig ileum. Estimates for carbachol and n-pentyl-trimethyl ammonium iodide were similar to published values obtained in similar conditions: those for n-hexyl-trimethyl ammonium iodide were slightly lower. 2. The results for the agonists, n-pentyl- and n-hexyl-trimethyl ammonium iodides and for the partial agonist, n-heptyl-trimethyl ammonium iodide were not as regular as was suggested by Stephenson, though there is an overall increase in apparent affinity with chain length. 3. Estimates of apparent affinity may be affected by hexamethonium, usually present in experiments on ileum. Its absence had little effect on the results with carbachol but reduced the estimates obtained with n-pentyl trimethyl ammonium, which has strong nicotinic effects compared with its muscarinic effects. On ileum treated with tetrodotoxin the values for n-pentyl trimethyl ammonium were similar to those obtained in the presence of hexamethonium (0.28 mM): slightly higher estimates of affinity were obtained in the presence of indomethacin (2.8 microM). The nicotinic effects of n-pentyl ammonium may involve the release of prostaglandins. 4. The estimates of apparent affinity did not depend on the method used to calculate them as the 'null' method and the 'operational' method give similar answers. Estimates of the transducer-ratio for the partial agonist, n-heptyl-trimethyl ammonium iodide, were numerically the same as those of its efficacy. 5. This work illustrates the use of 4-DAMP mustard as a tool for measuring the apparent affinity of agonists acting at muscarinic M3 receptors.

Animals↗
PubMed1992

The physical mechanisms of the perception of dampness in fabrics.

The detection of dampness in hygroscopic materials has been investigated both by subjective tests and by the application of a model of the physical mechanisms involved. Subjects were asked to rate the degree of dampness of a range of materials of different moisture contents after a short period of contact with the inner forearm. Skin and fabric inner surface temperatures were recorded. It was found that highly hygroscopic wool fabrics were perceived as being dryer and maintained a higher temperature at the skin surface than polyester, a less hygroscopic fabric, during fabric-skin contact. A physical model of the sorption/desorption process in hygroscopic materials has been developed from knowledge of fibre sorption kinetics and used to study the physical processes which take place at the skin-fabric interface during transient contact. These predictions agree well with the subjective responses and the measured temperatures.

Adult↗
PubMed1992

[Pathogenic factor (Dampness-heat) of glomerulopathy].

Mesangial proliferative glomerulonephritis (MsPGN) induced by chronic serum sickness in rabbits coincide with the human chronic progressive glomerulonephritis resulted from repeated infection, which is similar to pathologic changes of Dampness-Heat Syndrome. The experimental model of MsPGN was treated by Abelmoschus manihot. which could remove the Dampness-Heat. The amount of proteinuria in treating and control group were 62.68mg/24hr and 121.94mg/24hr respectively (P < 0.05), the number of cells in glomeruli were 61.54 and 80.39 respectively (P < 0.01), and diameters of glomeruli were 102.43 microns and 121.13 microns respectively (P < 0.01). It suggested that the drug could alleviate circulating immune complex (CIC) mediated renal injury.

Adolescent↗
PubMed1977

[Damping of oscillations in arterial pressure in the internal carotid arteries].

In dogs, recording of fluctuations of the inlet and outlet pressure in the internal carotid artery showed a decrease of the amplitude of fluctuations along the artery, the damping index (Id) being about 60-90%. The Id was almost unchanged when the skull was either intact or largely opened. The amplitude of blood pressure fluctuations in the circle of Willis was always decreased after occlusion of the vertebral arteries, being evidently unrelated to superposition of the pulse waves that reach the circle of Willis through the internal carotid and the vertebral arteries. Therefore the decrease of the amplitude of pulsation was dependent on the damping of the pulsatile waves along the internal carotid arteries. The rise of the tone of the latter increased the Id, and vice cersa. The Id was almost independent of the size of amplitude and of the frequency of the fluctuations of the systemic arterial pressure, but decreased when the latter rised.

Animals↗
PubMed1976

The damped pendular rotation test in central vestibular disorders.

Nystagmic rhythm in the damped pendular rotation test (DPRT) was analysed electronystagmographically both in healthy subjects (control) and patients with peripheral and central vestibular lesions. The patients were tested in a semi-dark room with eyes open and, in addition, a serial subtraction task was performed to maintain the state of alertness throughout the rotation. In the controls 49 years of age and under dysrhythmia was found in 11%, while in persons 50 years of age and over the abnormal rate was 29%. In patients with acoustic tumors, who had undergone surgery in which the translabyrinthine and middle fossa approach had been utilized, dysrhthmia was present post-operatively in only a few cases. In patients 49 years of age and under, operated on through the suboccipital approach, dysrhythmia was found post-operatively, or was at least more remarkable than pre-operatively in most cases. Nystagmic rhythm was, on the other hand, regular with cerebellar degenerative process or atrophy. Pre-operative dysrhythmia in patients with cerebellar and cerebral tumors was in some cases post-operatively converted to regular rhythmic nystagmus in pendular stimulations. Therefore, in cerebellar and cerebral tumors, dysrhythmia was thought to be due to secondary effects in brainstem, as these tumors can cause intracranial hypertension and circulatory disturbances in surrounding brain tissues. In Menière's disease and sudden deafness, dysrhythmia and salvos in DPRT were found in the age groups, 49 years of age and under and 50 years and over, as frequently as in the healthy and control group. In one case with Menière's disease which showed dysrhythmia, labyrinthectomy was done. This surgical manipulation of the labyrinth did not eliminate dysrhythmia, though a temporary improvement was obtained. This result indicates that the dysrhythmia may be of central origin. These findings also suggest that nystagmic rhythm in DPRT with mental arithmetic is significant in assessing brainstem dysfunctions, when the age and state of alertness of the patient are taken into consideration, or when comparing the pre- and post-operative findings in intracranial lesions.

Adolescent↗
PubMed1979

A data analysis microcomputer package (DAMP) for biomedical signals.

The advent of cheap, powerful microcomputer systems makes the analysis of data via sophisticated techniques available to the personnel who are non-specialists in computing systems. The DAMP package described here is intended for use on personal computers and has therefore been written in BASIC for portability. The analysis techniques are powerful, comprising algorithms to perform sample-data generation, plotting displays, digital data filtering, auto-correlation functions, fast Fourier transforms and autoregressive modelling. The last technique contains a number of options including the display of z-plane plots, frequency response of the model, residual plotting and auto-correlation of the residuals. Illustrative results are shown from psychological mood data and rat locomotor activity. The package is designed both to instruct a user in the techniques of spectral analysis, and also to provide a range of methods for investigating time and frequency behaviour of biomedical data.

Biomedical Engineering↗
PubMed2019

Increased acetylation of H3K14 in the genomic regions that encode trained immunity enzymes in lysophosphatidylcholine-activated human aortic endothelial cells - Novel qualification markers for chronic disease risk factors and conditional DAMPs.

To test our hypothesis that proatherogenic lysophosphatidylcholine (LPC) upregulates trained immunity pathways (TIPs) in human aortic endothelial cells (HAECs), we conducted an intensive analyses on our RNA-Seq data and histone 3 lysine 14 acetylation (H3K14ac)-CHIP-Seq data, both performed on HAEC treated with LPC. Our analysis revealed that: 1) LPC induces upregulation of three TIPs including glycolysis enzymes (GE), mevalonate enzymes (ME), and acetyl-CoA generating enzymes (ACE); 2) LPC induces upregulation of 29% of 31 histone acetyltransferases, three of which acetylate H3K14; 3) LPC induces H3K14 acetylation (H3K14ac) in the genomic DNA that encodes LPC-induced TIP genes (79%) in comparison to that of in LPC-induced effector genes (43%) including ICAM-1; 4) TIP pathways are significantly different from that of EC activation effectors including adhesion molecule ICAM-1; 5) reactive oxygen species generating enzyme NOX2 deficiency decreases, but antioxidant transcription factor Nrf2 deficiency increases, the expressions of a few TIP genes and EC activation effector genes; and 6) LPC induced TIP genes(81%) favor inter-chromosomal long-range interactions (CLRI, trans-chromatin interaction) while LPC induced effector genes (65%) favor intra-chromosomal CLRIs (cis-chromatin interaction). Our findings demonstrated that proatherogenic lipids upregulate TIPs in HAECs, which are a new category of qualification markers for chronic disease risk factors and conditional DAMPs and potential mechanisms for acute inflammation transition to chronic ones. These novel insights may lead to identifications of new cardiovascular risk factors in upregulating TIPs in cardiovascular cells and novel therapeutic targets for the treatment of metabolic cardiovascular diseases, inflammation, and cancers. (total words: 245).

Acetylation↗
PubMed1979

The undamped and damped series elastic components of a vascular smooth muscle.

Small arterial resistance vessels (internal diameter about 175 micrometer) have been mounted on a myograph that enabled their wall tension, T, and internal circumference, L, to be measured and controlled with a time resolution of about 4 ms. Maximally activated vessels were subjected to isometric releases (step changes in L) and isotonic releases (step changes in T) of varying extents and at two different temperatures (27 degree C and 37 degree C). The recovery from an isometric release was monotonic and did not include the two phases seen in skeletal muscles. The isotonic release response did, however, contain a velocity transient lasting about 150 ms: the velocity immediately after the release was about six times the steady shortening velocity. The form of both the isometric and isotonic release responses and their dependence on the extent of release can be explained in terms of a modified Hill model in which the "series elastic component" (SEC) is replaced by the series combination of an undamped-SED (that is, an undamped elastic element) and a damped-SEC (a Voigt element). Although the initial response to both types of release was independent of temperature, all stages of subsequent responses were temperature dependent, with Q10's in the range 1.5 - 2.0. The results suggest that the responses to isotonic and isometric releases may in part be due to active processes.

Animals↗
PubMedDate not supplied

Oculomotor localization relies on a damped representation of saccadic eye displacement in human and nonhuman primates.

The oculomotor system has long been thought to rely on an accurate representation of eye displacement or position in a successful attempt to reconcile a stationary target's retinal instability (caused by motion of the eyes) with its corresponding spatial invariance. This is in stark contrast to perceptual localization, which has been shown to rely on a sluggish representation of eye displacement, achieving only partial compensation for the retinal displacement caused by saccadic eye movements. Recent studies, however, have begun to case doubt on the belief that the oculomotor system possess a signal of eye displacement superior to that of the perceptual system. To verify this, five humans and one monkey (Macaca nemestrina) served as subjects in this study of oculomotor localization abilities. Subjects were instructed to make eye movements, as accurately as possible, to the locations of three successive visual stimuli. Presentation of the third stimulus (2-ms duration) was timed so that it fell before, during, or after the subject's saccade from the first stimulus to the second. Localization errors in each subject (human and nonhuman) were consistent with the hypothesis that the oculomotor system has access to only a damped representation of eye displacement--a representation similar to that found in perceptual localization studies.

Animals↗
PubMed1991

Xeroderma pigmentosum variant cells are less likely than normal cells to incorporate dAMP opposite photoproducts during replication of UV-irradiated plasmids.

Xeroderma pigmentosum (XP) variant patients show the clinical characteristics of the disease, with increased frequencies of skin cancer, but their cells have a normal, or nearly normal, rate of nucleotide excision repair of UV-induced DNA damage and are only slightly more sensitive than normal cells to the cytotoxic effect of UV radiation. However, they are significantly more sensitive to its mutagenic effect. To examine the mechanisms responsible for this hypermutability, we transfected an XP variant cell line with a UV-irradiated (at 254 nm) shuttle vector carrying the supF gene as a target for mutations, allowed replication of the plasmid, determined the frequency and spectrum of mutations induced, and compared the results with those obtained previously when irradiated plasmids carrying the same target gene replicated in a normal cell line [Bredberg, A., Kraemer, K. H. & Seidman, M. M. (1986) Proc. Natl. Acad. Sci. USA 83, 8273-8277]. The frequency of mutants increased linearly with dose, but with a slope 5 times steeper than that seen with normal cells. Sequence analysis of the supF gene showed that 52 of 53 independent mutants generated in the XP variant cells contained base substitutions, with 62 of 64 of the substitutions involving a dipyrimidine. Twenty-eight percent of the mutations involved A.T base pairs, with the majority found at position 136, the middle of a run of three A.T base pairs. (In the normal cells, this value was only 11%.) If the rate of excision of lesions from supF in the two cell lines is equal, our data suggest that XP variant cells are less likely than normal cells to incorporate dAMP opposite bases involved in photo-products. If such incorporation also occurs during replication of chromosomal DNA, this could account for the hypermutability of XP variant cells with UV irradiation.

Bacterial Proteins↗
PubMed1992

Cytotoxic fungal spores in the indoor atmosphere of the damp domestic environment.

Eight-three fungal isolates collected and cultured from the air spora of damp public sector Scottish housing have been screened for cytotoxic properties. A bioassay procedure has been utilised for this purpose involving cytotoxic effects on human embryonic diploid fibroblast lung cells grown as monolayer cultures within the wells of microtitre plates. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] biochemical assay system employed has revealed that 39 (47%) of the moulds investigated possessed spore-associated cytotoxic properties; a value which emphasises the potential health hazards of the continual inhalation of toxigenic fungal propagules by occupants of mouldy houses. Penicillia, the most prevalent fungi found in the internal atmosphere of the domestic environment, accounted for the great majority of cytotoxic strains identified.

Air Microbiology↗
PubMed1979

Ultrastructure of the turkey's basilar papilla and the damping elements in the scala media.

The ultrastructure of the turkey's inner ear was investigated by use of scanning and transmission electron microscopes. It was shown that hair cells of the basilar papilla are separated from each other by microvilli of the supporting cells. Organized compartments in the lower surface of the tectorial membrane of the turkey are arranged in polarized fashion as are the hair bundles. Kinocilia were not identified in the hair bundles examined in this study. Well-organized filamentous elements were observed in the cutucular plates. The continuation of these filamentous elements into the stereocilia indicates that the theory of adjustable resistor in generating cochlear potential may be closely associated with these elements. Membrane bound homogeneous material was found in the scala media between the tegmentum vasculosum and the tectorial membrane. The presence of this homogeneous damping material is believed to be essential in offsetting the sensitivity and enhancing the time resolution ability of the relatively short avian cochlea.

Animals↗
PubMed1976

[Damping method of traction].

Damping of the system of skeletal extension with steel coil springs, ball bearing blocks and capron fishing-line was shown by the authors to be a necessity, since the routinely used "rigid" systems proved to be less effective. The authors have elaborated a new method of elimination of angular deviations of fragments and dislocations in width.

Femoral Fractures↗
PubMedDate not supplied

Cardiac damage produced by transchest damped sine wave shocks.

High-energy transchest damped wave sine defibrillation shocks have been shown to produce cardiac damage when applied in rapid sequence. However, there are no reports as to whether single, threshold-intensity shocks produce damage. In this study, nonfibrillating dogs were subjected either to a single, threshold-intensity (1 A/kg) shock, or to a series of 6 shocks with high intensity (3 to 4.8 A/kg). Electrodes of 8 cm diameter were used to apply the shock through the chest wall. Dogs receiving shocks of adequate (but not excessive) strength to defibrillate showed no cardiac damage, although they exhibited transient ventricular arrhythmias after the shock was applied. All dogs receiving the higher intensity, multiple shocks showed gross and microscopic evidence of cardiac damage. Ventricular lesions were observed in both right and left ventricular free walls and were sometimes transmural in extent. ECG analysis of the records from the dogs receiving multiple, high-intensity shocks showed second and third degree A-V block, ventricular ectopic beats, ventricular tachycardia, S-T segment changes, and T-wave inversion. Although multiple, high-energy, high-current defibrillation shocks produce permanent cardiac damage in dogs, threshold shocks do not produce morphologic changes.

Animals↗
PubMedDate not supplied

Evaluation of the operating internal resistance, inductance, and capacitance of intact damped sine wave defibrillators.

A method is developed for determing actual values of circuit elements in a damped sine wave (Lown waveform) defibrillator solely from measurements of the output, using two or more power resistors and a storage oscilloscope. If a defibrillator containing capacitance C, inductance L, and internal resistance RI, is discharged into increasing 5- to 100-ohm resistive loads R, it is shown for underdamped output waveforms that â = RI/2L + R/2L and ĉ = CRI + CR, where â = pi[t2tan(pit1/t2)], ĉ = 2â/[â2 + (pi/t2)2], t1 = time from onset to peak, and t2 = time from onset to first zero crossing of the output waveform on the oscilloscope trace. Linear plots of â vs R are constructed for seven defibrillators, and values of RI and L computed as intercept/slope and 1/(2 slope) respectively. C is given by the slope of a linear plot of ĉ vs R. Delivered energy is accurately predicted as stored energy X R/(RI + R).

Electric Conductivity↗
PubMed1976

Damped pendular rotation nystagmus after unilateral labyrinthectomy or unilateral lateral semicircular canal block in squirrel monkeys.

Using a damped pendular rotation table, which provided an oscillation of 15.5 sec, per-rotatory nystagmus, was evaluated in six squirrel monkeys that underwent unilateral labyrinthectomy and five that underwent unilateral lateral semicircular canal block, both pre- and postoperatively. The bidirectional summation of the nystagmic slow-phase eye speed after unilateral labyrinthectomy and after unilateral lateral semicircular canal block showed similar reduction to about 60 per cent of the values obtained in the pre-operative status. Under the present test situation, both slow-phase eye speed and number of nystagmic beats in the monkeys after unilateral lateral semicircular canal block were larger by the ampullopetal stimulation than those evoked by ampullofugal stimulation. The relation between slow-phase eye speed and number of beats showed similar tendency when we compared pre-operative controls and the group after unilateral lateral semicircular canal block, but the monkeys after unilateral labyrinthectomy depicted different tendencies.

Animals↗