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PubMed2005

Laxatives for the treatment of hemorrhoids.

BACKGROUND: Symptomatic hemorrhoids are a common medical condition, which increase in prevalence in women during pregnancy and postpartum. Although the evidence appears to be inconclusive, narrative reviews and clinical practice guidelines recommend the use of laxatives (and fiber) for the treatment of hemorrhoids and relief of symptoms. This is due to their safety and low cost. OBJECTIVES: To evaluate the impact of laxatives on a wide range of symptoms in people with symptomatic hemorrhoids. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to 2005), EMBASE (1980 to 2005), CINAHL (1982 to 2005), BIOSIS, and AMED (Allied and Alternative Medicine Database), for eligible trials (including conference proceedings). We sought missing and additional information from authors, industry, and experts in the field. SELECTION CRITERIA: We selected all published and unpublished randomised controlled trials that compared any type of laxative to placebo or no therapy in any patient population. DATA COLLECTION AND ANALYSIS: Two authors independently screened studies for inclusion and retrieved all potentially relevant studies. Data were extracted from studies that met our selection criteria on study population, intervention used, pre-specified outcomes, and methodology. We extracted methodological information for the assessment of internal validity: existence and method of generation of the randomization schedule, and method of allocation concealment; blinding of caregivers and outcomes assessors; numbers of and reasons for participants lost to follow up; and use of validated outcome measures. MAIN RESULTS: Seven randomised trials enrolling a total of 378 participants to fiber or a non-fiber control were identified. Meta-analyses using random-effects models showed that laxatives in the form of fiber had a beneficial effect in the treatment of symptomatic hemorrhoids. The risk of not improving hemorrhoids and having persisting symptoms decreased by 53% in the fiber group (risk reduction (RR) 0.47, 95% CI 0.32 to 0.68). These results are compatible with large treatment effects regarding prolapse, pain, itching, although the pooled analyses showed a tendency toward no-effect for these parametres. The effect on bleeding showed a significant difference in favour of the fiber (RR 0.50, 95% CI 0.28 to 0.89). Studies including data on multiple follow ups (usually after six weeks and three months) showed consistent results over time. However, we have to stress two possible limitations of this review: the risk of publication bias, and only moderate study quality. AUTHORS' CONCLUSIONS: The use of fiber shows a consistent beneficial effect for relieving overall symptoms and bleeding in the treatment of symptomatic hemorrhoids.

Cathartics↗
PubMedDate not supplied

Neuron types, receptors, behavior, and taste quality.

Neurophysiological studies on chorda tympani (CT) single fibers and behavioral studies on generalization of learned aversions in hamsters (Mesocricetus auratus) are reviewed. The work on hamsters is compared to work on other species, including the laboratory rat and several primate species, including humans. This body of data demonstrates associations between response profiles of physiologically defined specialist CT neurons and behavioral stimulus generalizations on one hand, and characteristics of putative taste receptors, on the other. Response profiles of generalist CT neurons are similarly associated with receptor characteristics, but are not associated with specific behavioral discriminations. The associations of peripheral nerve data with both receptor and behavior strongly suggest specific codes for "sucrose-like" and "NaCl-like" taste qualities. Definitive conclusions regarding "patterns" or "labeled lines" requires an understanding of mechanisms of central neural processing of the several specialist and generalist taste-afferent inputs.

Animals↗
PubMed1995

[Possibilities for imaging the retinal nerve fiber layer with the scanning laser ophthalmoscope].

BACKGROUND: Documentation of the retinal nerve fiber layer using red free light is not established as a routine method. The reasons for this are the difficulties involved in taking the pictures and developing them, especially in glaucoma patients, and the need for maximum pupil dilation. The scanning laser ophthalmoscope (SLO) allows fast and easy documentation of the fundus with the possibility of simultaneous image control during the examination. PATIENTS AND METHODS: Nerve fiber layer images of 48 eyes of 25 patients taken with the argon blue light of the SLO were compared to conventional photographs of the nerve fiber layer with red-free light. In addition, we compared documentation of the nerve fiber layer using argon-blue or argon-green light in the SLO. RESULTS: The nerve fiber layer images obtained with the SLO were of good quality for all 48 eyes included in the study, whereas with conventional photography we could not obtain images in 9 eyes. There was a high correlation between the two methods in the detection of localized damage or zones with diffuse nerve fiber atrophy for the 39 eyes documented with both methods, and there was better image quality in some using the SLO. The use of blue light permits the nerve fiber layer to be seen more easily than with green light. CONCLUSIONS: The SLO allows nerve fiber bundle defects or diffuse atrophy to be detected similar to conventional fundus photographs using red free light sources. There is no further need to dilate the pupil maximally due to the confocal principle and the scanning technique. The smaller angle of view of the SLO requires fixation movements of the patient being examined for the detection of beginning peripheral nerve fiber bundle defects.

Adult↗
PubMed1975

X-ray fiber diffraction evidence for neighbor exclusion binding of a platinum metallointercalation reagent to DNA.

Good quality x-ray diffraction patterns have been obtained of polycrystalline fibers containing 2-hydroxyethanethiolato(2,2'2"-terpyridine)platinum(II) bound to calf thymus DNA by intercalation. The photographs strongly support the neighbor exclusion binding model in which electron-dense platinum atoms are regularly distributed at 10.2 A intervals, every other interbase pair site.

Animals↗
PubMed2006

Surface preparation and coupling in plastic scintillator dosimetry.

One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity.

Artifacts↗
PubMed1992

[International control of the quality of microscopic-numerical analysis of the levels of man-made mineral fibers (MMMF) in the air of the work area].

In the years 1986-1990 the Institute of Occupational Medicine in Lodz (Department of Aerosols) participated in seven exchanges of preparations within the WHO/Euro MMMF Reference Scheme programme. The number of persons analysing the preparations increased from three, during the first exchange, to seven in the sixth. Markings in the 1st and 3rd exchange constituted two thirds of the reference markings. In the 2nd, 5th and 7th exchange the markings were similar, and in the 6th exchange they were lower than in the reference markings. According to the accepted system, the markings of the standardized density in four exchanges (2nd, 5th, 6th and 7th) were determined as class I (0.70-1.40), and in the remaining exchanges (1st, 3rd and 4th) of class II (0.50-2.00).

Air Pollutants, Occupational↗
PubMed2000

Growth- and breed-related changes of muscle fiber characteristics in cattle.

The objective of this study was to investigate the growth- and breed-related changes of muscle fiber characteristics in cattle and their importance to meat quality. Four cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus as a beef type, Galloway as a hardy type, Holstein Friesian as a dairy type, and double-muscled Belgian Blue as an extreme type for muscle growth were used. Between 5 and 17 bulls of each breed were slaughtered at 0, 2, 4, 6, 12, 18, and 24 mo of age. Muscle fiber traits were determined and classified by computerized image analysis, and several measures of meat quality were also determined, including shear force value, meat color, and i.m. fat content. The postnatal growth of semitendinosus muscle in cattle was characterized by a nearly 10-fold increase of muscle fiber area from birth to 24 mo of age. In the first few months after birth, a transformation of type IIA fibers into IIB fibers was found, whereas type I fibers were nearly unaffected by age. The apparent total muscle fiber number of semitendinosus muscle did not increase during postnatal life. These results confirm that the fiber number is determined in embryonic development. Throughout the study, the double-muscled Belgian Blue (BBDM) bulls had almost twice the fiber number of the other breeds, emphasizing a more extensive hyperplasia of muscle fibers during embryonic development in BBDM compared with the other three breeds. The apparent number of type I fibers was, however, not affected by breed, which suggests that the additional fibers found in BBDM postnatally were type IIB and IIA fibers. We did not find significant differences in muscle fiber total number, muscle fiber type frequencies, or meat quality characteristics among breeds, with the exception of BBDM. Having pooled the four breeds, paler meat was related to a higher frequency of type IIB fibers, a lower area of type IIA and type I fiber, and a higher total muscle fiber number. These findings based on data of double muscling give us some hints for biological causes for the variation of meat quality. Further investigation, in particular within each breed, is necessary to identify the superior fiber traits for bovine meat production.

Animal Husbandry↗
PubMed2003

Slow fiber cluster pattern in pig longissimus thoracis muscle: implications for myogenesis.

Recent evidence implicates fiber type proportions as playing a role in meat eating quality, and in pigs it has been suggested that the slow oxidative fibers contribute to both juiciness and tenderness. The fiber distribution in pigs is different from that found in most other species, in which the various types of skeletal muscle fiber are distributed in a "checkerboard" pattern, because in pigs the slow oxidative fibers have a clustered distribution. The initial processes leading to fiber clustering are likely to occur during myogenesis, but the precise mechanistic aetiology of this patterning and whether the slow oxidative fiber clusters occur in a random or ordered fashion is unknown. In the present study longissimus thoracis muscle from Large White crossbred pigs was sampled at the 10th rib, 48 h postmortem. Transverse cryo-sections were cut and histochemically stained to allow the identification of the main muscle fiber types: slow oxidative, fast glycolytic, and fast oxidative glycolytic. Images of the sections were captured and analyzed using point processes and Voronoi Tesselations to examine the randomness and spatial distribution of the clusters of slow oxidative fibers found in pig longissimus thoracis muscle. The results showed that an assumption of complete spatial randomness can be rejected and that a mathematical model incorporating a minimum distance of 1.7 to 2.0 microm between cluster centers produced fiber patterns similar to those observed in the original transverse sections of the muscle. In addition, if it assumed that the central fiber in each cluster is derived from primary myoblast progenitors, these results suggest that there may be some degree of repulsion between the primary fibers during the initial stages of cluster formation. The mechanistic basis of such repulsion is not clear, but it is speculated that secreted factors, such as sonic hedgehog or myostatin may play a role.

Algorithms↗
PubMed1983

Differences in muscle spindle structure between pigeon muscles used in aerial and terrestrial locomotion.

Muscle spindle density (number of spindles per gram of muscle) of all 29 muscles of the forearm and leg of the domestic pigeon was evaluated by counting receptors in van Gieson-stained serial cross sections. Extra- and intra-fusal fiber-type profiles were determined from histochemical preparations. Muscles of the leg had on the average significantly more avian slow-twitch oxidative extrafusal fibers (22.5 vs. 0.8%) and slower contraction times than muscles of the forearm, but fiber-type profiles and gross actions of muscles showed no consistent relation to the relative abundance of receptors. Differences in intrafusal fiber-type composition among spindles were sought because of their potential effect on the quality of the afferent discharge. The number of intrafusal fibers per spindle was on the average significantly less (4.57 vs 5.99) in the muscles of the leg than in those of the forearm; and of spindles with the same number of intrafusal fibers, those in the leg had smaller periaxial spaces. Distribution of intrafusal fiber types identified with the myofibrillar adenosine triphosphatase reaction differed among spindles of varying sizes. An acid- and alkali-labile type occurred most frequently (P = 0.05) in spindles with one to three intrafusal fibers, and an acid-labile and alkali-stable type was most often seen (P = 0.05) in spindles with 4 to 7 intrafusal fibers. The smaller receptors were more abundant in the leg, while the larger ones were about equally distributed between the two extremities. Muscle fibers with dimensions that sometimes approached small extrafusal fibers were present in about 3% of the axial bundles examined, most of them in the forearm. The selective morphological variation of avian muscle spindles may represent the structural basis for qualitatively different afferent discharges that relate to the characteristic types of locomotion served by the two extremities.

Animals↗
PubMed2004

Nerves and sensations from the eye surface.

Because vision plays a critical role in obtaining information from the external world, evolutionary development has provided the structures that sustain this function with special protection against injury. Thus, the cornea possesses the richest sensory innervation of the body to detect noxious stimuli. The trigeminal sensory neurons that innervate the eye vary in their chemical composition and electrophysiological properties, and can be classified according to the stimuli that activate them preferentially: mechanical forces, temperature, or irritant chemicals. Different classes of noxious stimuli (mechanical injuries, heat, extreme cold) activate to a different degree the various populations of sensory fibers of the ocular surface and evoke unpleasant sensations of distinct quality. When injured either accidentally or following ocular surgery, sensory nerve fibers of the ocular surface may form neuromas that develop abnormal activity and become the source of unpleasant sensations, such as pain, dryness, grittiness, etc. In parallel, their response to natural stimuli is diminished. The possibility of hypesthesia and dysaesthesias must be considered in the assessment of the risks of therapeutic procedures that involve damage to ocular sensory nerves.

Journal Article↗
PubMed1993

A simplified method for selecting a carbon-fiber electrode in pulse voltammetry.

A method for selecting a usable carbon-fiber electrode using the equivalent resistance and capacitance is presented. This method uses an instrument with a PC-based look-up table for measuring the electrical characteristics of a carbon-fiber electrode in pulse voltammetry. Using this instrument, the equivalent resistance and capacitance of the carbon-fiber electrode in saturated sodium chloride solution can be obtained. This instrument includes a decade resistance box, a peak current detection and hold circuit, a half peak comparator and a decay duration counter. A look-up table is established by using RC circuits to emulate the electrochemical reaction of the carbon-fiber electrode in pulse voltammetry. The equivalent resistance is obtained from the decade resistance box according to Kirchhoff's law. Then the equivalent capacitance is determined from the decay duration counter reading and equivalent resistance with the look-up table via a PC interpolation program. After obtaining the equivalent resistance and capacitance of an electrode, the values are compared with the usable thresholds. This method provides an effective quality evaluation index of carbon-fiber electrode for the user in order to reduce electrode-induced experimental failure. The method is also available for other kinds of carbon-fiber electrodes as long as their look-up table and desired thresholds are established.

Electric Conductivity↗
PubMed1978

Recent progress in dietary fiber (plantix) in human nutrition.

Dietary fiber was extensively discussed in an article by G.A. Spiller and R.J. Amen in this journal in 1975 (Volume 7 Issue 1). The progress in this field has been tremendous in the past 2 years. What was an uncertain field in 1975 and what at that time to some investigators still appeared as a hypothesis or fad without much proof has turned into a much more respected part of nutritional sciences. The scientific quality of recent studies on dietary fiber in human nutrition shows a great deal of sophistication and care. Improved analytical methodologies are being used more extensively. Many nutritionists and clinicians have accepted the fact that a reasonable increase in the dietary fiber intake in the U.S. and U.K would be advisable. In this article, the possible beneficial effects of dietary fiber on health, the possible harmful side effects, and the food science aspects are carefully discussed after an update on chemistry, analytical procedures, and nomenclature. Undoubtedly, dietary fiber has found a new niche in the sciences of nutrition, medicine, epidemiology, and foods.

Adult↗
PubMed2004

Laser ablation of dental tissues with picosecond pulses of 1.06-microm radiation transmitted through a hollow-core photonic-crystal fiber.

Sequences of picosecond pulses of 1.06-microm Nd:YAG laser radiation with a total energy of approximately 2 mJ are transmitted through a hollow-core photonic-crystal fiber with a core diameter of approximately 14 microm and are focused onto a tooth's surface in vitro to ablate dental tissue. The hollow-core photonic-crystal fiber is shown to support the single-fundamental-mode regime for 1.06-microm laser radiation, serving as a spatial filter and allowing the laser beam's quality to be substantially improved. The same fiber is used to transmit emission from plasmas produced by laser pulses onto the tooth's surface in the backward direction for detection and optical diagnostics.

Dental Enamel↗
PubMed2005

Design principles of multifiber resonant directional couplers with hollow Bragg fibers: example of a 3 x 3 coupler.

When several hollow photonic crystal fibers (HPCFs) are placed in proximity to each other, radiation-induced interfiber coupling between their core guided modes is observed. Under certain conditions coupling between the core modes of two touching collinear fibers can have a resonant increase via excitation of a low-quality intermirror cavity resonant state. Such coupling, however, decreases dramatically within the first micrometer of intermirror separation. Moreover, when fibers are touching, in the frequency domain a large number of accidental degeneracies with fiber surface and mirror states complicate the design of a stable 2 x 2 coupler. To alleviate these problems we consider coupling among three hollow Bragg fibers. When placed in the vertices of an isosceles triangle, even for a finite separation between fibers, triangular interfiber cavity forms a high-quality resonator that can be tuned via additional structural elements to a particular frequency of interest. Interfiber surface states are suppressed by keeping the fiber separation finite, thus allowing stable coupling conditions in a 3 x 3 HPCF coupler configuration.

Journal Article↗
PubMed2003

Liquid light guides versus fiber light guides in clinical near-infrared spectroscopy.

New commercial liquid light guides have an advantage over fiberoptic bundles regarding breakage during clinical handling. We investigate the quality of clinical data collection using liquid versus fiber bundles as receivers. A four-wavelength NIRO-500 near-IR spectrophotometer is used with single-terminal fiber bundles, multiterminal fiber bundles, or a single-terminal liquid light guide as receivers. Repeated 3-min trials are done using a stable phantom, an unstable phantom, and the human forearm. A least-squares linear best-fit line and its root mean square error (RMSE), a measure of signal noise, are derived for each wavelength of each trial. The mean and standard deviations for the RMSEs of the single-terminal fiber optic receiving cable are derived for comparison standards. The liquid light guides have 51 to 174% greater signal noise with RMSEs 2 to 12 standard deviations above the mean of the single-terminal fiber bundle. The multiterminal fiber bundles have 49% less to 32% greater signal noise and had RMSEs within 1 to 4 standard deviations above the mean of the single-terminal fiber bundle. These comparisons suggest fiber optic bundles are preferable for clinical near-IR spectroscopy (NIRS) applications requiring low signal noise.

Blood Volume↗
PubMed1994

Reproducibility of retinal nerve fiber layer evaluation by dynamics scanning laser ophthalmoscopy.

Scanning laser ophthalmoscopy is a laser-based image acquisition technique, which greatly improves the quality of the examination of the fundus and the retinal nerve fiber layer. To assess retinal nerve fiber layer imaging by scanning laser ophthalmoscopy and evaluate intra- and interobserver reproducibility in the classification of retinal nerve fiber layer defects, three independent observers evaluated on two separate occasions the videotaped images of 150 eyes of 80 consecutive patients with ocular hypertension or glaucoma. Ophthalmoscopy was performed using argon blue light (488 nm), confocal apertures of 3 to 1 mm, and 40-degree and 20-degree field angles. Of 150 eyes, 20 (13.3%) were excluded from the study because of the poor quality of the images (clinically significant cataract or myopic peripapillary atrophy). The retinal nerve fiber layer was evaluated qualitatively according to a standard classification: normal pattern, slit, wedge, and diffuse defects. Intraobserver reproducibility, evaluated by kappa statistic, was excellent (> or = 0.75): observer A = 0.78 (95% confidence limits, 0.67-0.88); observer B = 0.84 (95% confidence limits, 0.72-0.96); and observer C = 0.79 (95% confidence limits, 0.67-0.91). Interobserver reproducibility was also excellent in all cases: observers A-B = 0.84 (95% confidence limits, 0.71-0.98); observers A-C = 0.76 (95% confidence limits, 0.65-0.87); and observers B-C = 0.80 (95% confidence limits, 0.69-0.92). Kappa values ranged between 0.59 and 0.69 for intraobserver reproducibility and between 0.55 and 0.69 for interobserver reproducibility when using only those eyes in which abnormalities were noted by at least one observer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Improvement of the digestibility of the proteins of the red alga Palmaria palmata by physical processes and fermentation.

Palmaria palmata (dulse) is an edible red alga constituting a potential protein source in human diet. However, previous studies showed that the digestibility of dulse proteins is bad because of the cell-wall encapsulating cytoplasmic proteins and the presence of fibers. The water-soluble xylan, present in high proportions in dulse, could be involved to explain the weak digestibility of proteins. To limit the influence of fibers and to improve the nutritional quality of these proteins, we have treated dulse by physical processes or by fermentation by moulds. After a 30 min predigestion by pepsin followed by a 6 h digestion into a cell dialysis containing porcine pancreatin, the corrected in vitro digestibility of crude dulse was very low (about 1.5% after correction by digestibility blank). The in vitro protein digestibility was estimated to 58% of that of casein for dulse samples obtained after washing in demineralized water and grinding in liquid nitrogen. The in vitro protein digestibility of fermented samples was 45%-65% of that of casein. After physical treatment, the digestibility improvement was related to the elimination of soluble molecules such as xylan and mineral salts. The improvement observed after fermentations seemed due to the degradation of insoluble fibers.

Aspergillus↗