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PubMed2001

Structural evidence of human nuclear fiber compaction as a function of ageing and cataractogenesis.

This study was conducted to quantify structural change associated with human nuclear fiber compaction as a function of ageing and nuclear cataract formation. Normal donor lenses in three age ranges, young (15--25 years), middle-aged (36--46 years) and aged (59--81 years) were compared to each other and to age-related nuclear cataracts (55--81 years) surgically removed by extracapsular extraction. Several structural modifications which occurred as a manifestation of fiber compaction were noted. In the fetal nucleus (FN), the average anterior and posterior fiber angles decreased approximately 20% with age. Additionally, there was a reduction in the thickness of both the anterior and posterior segments of fetal fibers with age. On average, the anterior--posterior (A--P) axis in the embryonic nucleus (EN) decreased 33% with age. The average length of EN fibers decreased significantly (37%) as a function of age. This change in EN fiber length was accomplished by effecting compaction folds along fiber length. By comparison, in nuclear cataracts the anterior and posterior angles of FN fibers were about 12% smaller than comparably aged normal lenses. Similarly, the A--P axis and the length of EN fibers were 13% smaller than age-matched normals. Nuclear fiber compaction in early adulthood was significant and may contribute to the lens hardening and loss of accommodative ability symptomatic of presbyopia. 3D-CAD reconstructions of fiber compaction show how the reduction in the spacing of lateral interdigitations along fiber length causes an increase in the fiber membrane complexity along the A--P axis in relation to fiber cytoplasm as light passes through lenses. These results may explain, at least in part, how an increase in large particle scatter occurs as light is transmitted through fiber membranes, resulting in reduced lens optical quality as a function of age. By extrapolation, the significantly increased compaction of nuclear fibers in age-related nuclear cataracts may be a contributing factor for excessive scatter in nuclear opacification.

Adolescent↗
PubMed2007

Fiber laser using a microsphere resonator as a feedback element.

We show that a glass microsphere resonator can be used as a wavelength-selective mirror in fiber lasers. Due to their high quality factor (Q approximately 10(8)), microsphere resonators possess a narrow reflection bandwidth. This feature enables construction of single-frequency fiber lasers even when the laser cavity is long. Nonlinear effects (such as stimulated Raman lasing) were also observed in our setup at relatively low pump powers.

Journal Article↗
PubMed2004

Nutrient intake and diet quality in patients with systemic lupus erythematosus on a culturally sensitive cholesterol lowering dietary program.

OBJECTIVE: To evaluate the effect of a culturally sensitive cholesterol lowering dietary program on energy, protein, fiber, vitamin and mineral intake, diet quality, and hemoglobin levels in patients with systemic lupus erythematosus (SLE). METHODS: Seventeen patients with SLE were randomized to a Step II diet intervention group or a control group for 12 weeks. The diet intervention was made up of weekly group sessions during the first 6 weeks followed by telephone counseling every 2 weeks for the last 6 weeks. Food intake was assessed by 3-day food record at baseline, 6, and 12 weeks. Diet quality was assessed by expressing the nutrients as a percentage of the Dietary Reference Intakes of the US National Academy of Sciences, or as a percentage of the nutrient guidelines by the National Cholesterol Education Program, Adult Treatment Panel III. Between- and within-group changes in nutrient intakes were assessed by repeated measures ANOVA. RESULTS: The changes in nutrient intakes were not significantly different between the groups for any of the nonfat nutrients except vitamin B12 (p = 0.05), which decreased in the diet group and increased in the control group. Within-group analysis showed a significant reduction (p = 0.0003 to 0.02) in the diet group in energy and sodium intake at 6 and 12 weeks and B12 intake at 12 weeks compared to the respective baseline values (28-32%, 37-41%, and 43%, respectively). Sodium intake decreased to 66-71% of the total sodium allowance (< 2400 mg per day) in the diet group. The intervention was successful in maintaining adequate intakes or even increasing intakes of most nutrients except B12, dietary fiber, folate, calcium, and iron, which were slightly higher or below 67% of the Dietary Reference Intakes or other dietary guidelines. Anemia, as assessed by hemoglobin levels, was present throughout the study and did not correlate with iron intake. CONCLUSION: This culturally sensitive cholesterol reducing diet program was successful in decreasing sodium intake and maintaining adequate intakes of most nutrients except B12, dietary fiber, iron, calcium, and folate. Future intervention studies in patients with SLE need to pay special attention to these nutrients and the presence of anemia.

Adult↗
PubMed2001

Self-rated quality of life measures: effect of change to a low-fat, high-fiber, fruit and vegetable enriched diet.

The Polyp Prevention Trial (PPT) was a multicenter, randomized clinical trial to determine the effect of a low-fat (20% of energy from fat), high-fiber (18 g/1,000 kcal/day), high-fruit/vegetable (3.5 servings/1,000 kcal/day) eatingplan on the recurrence of large bowel adenomatous polyps. The PPT provided an opportunity to examine the impact of dietary changes on quality of life. At baseline and annuallyfor 4 years, participants in the Quality of Life Substudy of PPT completed a Quality of Life Factors (QF) Questionnaire, a modified Block-National Cancer Institute Food Frequency Questionnaire, and a Health and Lifestyle Questionnaire. The 51-item QF Questionnaire assessed changes in nine domains: taste, convenience, cost, self-care, social, health assessment, health belief health action, and life satisfaction. The analysis compared annual changes in domain scores for intervention (n = 194) and control (n = 200) participants. At Year 1, 363 (92%) completed a questionnaire, and 325 (82%) participants completed a Year 4 questionnaire. There were no statistically significant differences between treatment groups in the change from baseline to Year 1 for the convenience, cost, taste, health assessment, and life satisfaction domains. At Year 1, intervention participants rated the self-care (p < .001), health belief (p = .021), and health action (p < .001) domains significantly higher and the social domain significantly lower (p <.001) than control participants. These changes were consistent through Years 2, 3, and 4. This study

Adenomatous Polyps↗
PubMed2006

Growth- and breed-related changes of muscle bundle structure in cattle.

The objective of this study was to investigate the changes in muscle fiber bundles of cattle of different breeds during growth. Different numbers of muscle fibers are surrounded by connective tissue to form bundles macroscopically visible as meat fibers or meat grain, a common meat quality trait. To determine the influence of breed and age on morphological characteristics of muscle fiber bundles, 4 cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus, a typical beef cattle; Galloway, a smaller beef type; Holstein Friesian, a dairy type; and double-muscled Belgian Blue, an extreme type for muscle growth, were used. Between 5 and 15 bulls of each breed were slaughtered at 2, 4, 6, 12, or 24 mo of age, and slices of semitendinosus muscle were removed. Muscle structure characteristics were determined by computerized image analysis. During growth, the muscle cross-sectional area enlarged (P < 0.001) about 5-fold in double-muscled Belgian Blue bulls and about 4-fold in the other breeds. This was a result of the enlargement (P < 0.001) of primary bundles and muscle fibers. The bundle size was similar (P > or = 0.15) in bulls of German Angus and Galloway in all age groups and was doubled (P < 0.001) in double-muscled Belgian Blue animals from 4 mo of age on. The Holstein Friesian bulls had the smallest (P < 0.001) muscle fiber bundles at 24 mo of age. The number of muscle fibers per bundle and the number of bundles per muscle remained nearly constant (P > 0.05) during growth. This supports the existing view that the structure of the muscle is already fixed in prenatal life. The double-muscled Belgian Blue bulls showed a more than 2.5-fold greater (P < 0.001) number of muscle fibers per primary bundle compared with the other breeds investigated. The larger muscle fiber bundles led to a smaller amount of connective tissue per muscle area in double-muscled cattle. The coarser grain of meat in double-muscled Belgian Blue bulls and in older animals was not related to greater shear force values.

Animals↗
PubMedDate not supplied

Visualization of fibrous and thread-like data.

Thread-like structures are becoming more common in modern volumetric data sets as our ability to image vascular and neural tissue at higher resolutions improves. The thread-like structures of neurons and micro-vessels pose a unique problem in visualization since they tend to be densely packed in small volumes of tissue. This makes it difficult for an observer to interpret useful patterns from the data or trace individual fibers. In this paper we describe several methods for dealing with large amounts of thread-like data, such as data sets collected using Knife-Edge Scanning Microscopy (KESM) and Serial Block-Face Scanning Electron Microscopy (SBF-SEM). These methods allow us to collect volumetric data from embedded samples of whole-brain tissue. The neuronal and microvascular data that we acquire consists of thin, branching structures extending over very large regions. Traditional visualization schemes are not sufficient to make sense of the large, dense, complex structures encountered. In this paper, we address three methods to allow a user to explore a fiber network effectively. We describe interactive techniques for rendering large sets of neurons using self-orienting surfaces implemented on the GPU. We also present techniques for rendering fiber networks in a way that provides useful information about flow and orientation. Third, a global illumination framework is used to create high-quality visualizations that emphasize the underlying fiber structure. Implementation details, performance, and advantages and disadvantages of each approach are discussed.

Anatomy, Cross-Sectional↗
PubMed1998

NMR spectroscopy and MRI investigation of a potential bioartificial liver.

NMR feasibility was established for a coaxial hydrophobic-membrane bioreactor containing isolated rat hepatocytes with features designed to mimic the human liver. A novel triple-tuned NMR probe and a perfusion system controlling temperature, gas concentrations, flow-rate, and pH were used. We determined the optimum coaxial interfiber distance (i.e. diffusion distance) for maintaining hepatocyte viability in two bioreactor prototypes. Prototype no. 1 and no. 2 had diffusion distances of 500 microns and 200 microns, respectively. Cell viability was established by 31P NMR and trypan blue exclusion. Only prototype no. 2 maintained cell viability for more than 6 h, indicating the importance of diffusion distance. 31P spectra obtained over this 6 h time period were similar to in vivo spectra of rat liver. The 31P spectra were found to be more sensitive to subacute cell viability than trypan blue exclusion. In the 1H and 31P spectra, 1H2O and inorganic phosphate signals were split in two at all flow-rates, probably due to bulk magnetic susceptibility effects originating from the three bioreactor compartments. MRI was useful for quality control and determining flow dynamics, fiber integrity, and cell inoculate distribution. MRI revealed that the inner fibers were not centered in either prototype. Although an increased flow-rate did not influence spectral resolution or chemical shifts, significant degradation of MRI quality occurred above 50 mL/min. NMR spectroscopy and imaging provide valuable, real-time information on cell biochemistry and flow dynamics which can be used in development and monitoring of bioreactors designed as artificial livers.

Animals↗
PubMed2006

A systematic review of diagnostic studies in myasthenia gravis.

We performed a systematic review to identify studies that reported the accuracy of tests for the diagnosis of myasthenia gravis. We identified 20 studies of reasonable, although variable, methodological quality upon which to base estimates of the accuracy of the ice test, rest test, Tensilon test, acetylcholine receptor antibodies, repetitive nerve stimulation and single fiber electromyography for the diagnosis of myasthenia gravis. After examining inter-study heterogeneity for each diagnostic modality, we calculated pooled estimates of sensitivity and specificity as well as positive and negative likelihood ratios. Results are reported separately for ocular and generalized myasthenia. Studies that have examined the performance of anti-acetylcholine receptor antibody testing and single fiber electromyography were generally of better quality than those that examined other diagnostic modalities. We suggest that caution should be exercised in the interpretation of the diagnostic performance of these tests given the methodological limitations of the studies upon which test performance is based.

Cholinesterase Inhibitors↗
PubMed1998

Immunoelectrodes in protein detection: comparison between glassy carbon and a semimetallic Ni/P thin film as binding support. Biological applications.

Though immunoelectrodes can allow direct detection of very low protein amounts (about 0.1 pmol) in vitro and in vivo, they are not yet widely used because they need quality improvement. Based on a few works devoted to the basic electrochemical phenomenon occurring when antibodies are linked onto a solid support and during antigen/antibody complex formation, we have coated two different supports with antibodies: the classical glassy carbon fiber or an epoxy plate covered with an amorphous semimetallic (nickel/phosphorus) thin film obtained by means of an electrochemical deposit. The antibody/antigen complex formation induces direct and/or indirect ionic movements and a current flow through the conductive support toward a very low-noise and high-sensitivity preamplifier stage in an I/V configuration. The proposed electrochemical treatment (hydrophilization), applied to both carbon and Ni/P electrodes, improves antibody binding and reliability of the response to antigens. The Ni/P probes present several advantages when compared to carbon fiber: better conductivity, possibility of surface quality control, and semimetallic nature, making them unbreakable. Several applications were proposed: somatostatin-14 detection with both carbon fiber and Ni/P plate electrodes, and histamine detection in simple and complex fluid media. Dose-response curves and analysis of the results lead us to conclude that the obtained currents are directly related to the quantity of antigen.

Antigen-Antibody Reactions↗
PubMed1990

Differential passage rates and digestion of neutral detergent fiber from grain and forages in 30, 60 and 90% concentrate diets fed to steers.

Six ruminally cannulated steers were used to determine the effects of altering dietary concentrates on fiber digestion. Diets contained 30, 60 or 90% of a concentrate based on flaked sorghum grain plus a 50:50 mixture of wheat straw and alfalfa hay. Total tract digestibility of NDF was not altered, but digestibility of potentially digested NDF (PDF) decreased (P less than .05) from 92 to 48% as concentrates increased from 30 to 90% of diet DM. Ruminal passage rate for straw (3.4 and 3.0%/h) and for hay (4.6 and 4.7%/h) was unchanged when concentrate was increased from 30 to 60%, but it decreased by 28 (2.2%/h) and 13% (4.1%/h), respectively (P less than .05), when concentrates were increased to 90%. Passage rate for grain (5.3, 5.1 and 4.4%/h) and fluid (9.3, 10.0 and 8.2%/h) was not influenced by concentrate percentage. Calculated ruminal digestibilities of NDF in individual ingredients did not differ between 30 and 60% concentrates, but they decreased (P less than .05) by 72, 57 and 34% for straw, hay and grain when concentrate was increased to 90%. Because of their relative contribution to total diet NDF, straw, hay and grain accounted for 28, 18 and 54% of the total decrease in estimated fiber digestion. It is concluded that PDF as well as NDF should be evaluated in studies of concentrate effects on fiber digestion, and that dietary concentrate level has more influence on passage rate of low-quality forage than on passage rate of grain or high-quality forage. In 90% concentrate diets, although fiber digestibility was depressed more for forage than for grain, grain accounted for most of the depression in fiber digestion because grain was the primary source of dietary fiber.

Animal Feed↗
PubMedDate not supplied

International survey on dietary fiber: definition, analysis, and reference materials.

An international survey was conducted to get the views of 147 professionals in the field on the definition of dietary fiber. The survey also solicited opinions on analytical methods for nutrition labeling, quality control, and nutrition research. The survey finds that dietary fiber is generally defined as polysaccharides and lignin that are not hydrolyzed by human alimentary enzymes. Support is strong for expansion of the definition to include oligosaccharides that are resistant to hydrolysis by human alimentary enzymes. Among techniques for nutrition labeling and quality control, enzymatic-gravimetric methods get the highest support. For nutrition research, more detailed methods such as gas-liquid chromatography and liquid chromatography were considered more appropriate. Respondents support labeling of total, soluble, and insoluble dietary fiber or total dietary fiber alone as sufficient for nutrition labeling of food packages. However, for nutrition research, detailed analytical methods, improvements in accuracy (i.e., closer simulation of in vitro techniques to conditions of human gastrointestinal tract), and improvements in precision and simplicity are suggested. Less than 20% of the participants use reference materials for dietary fiber analysis.

Animal Nutritional Physiological Phenomena↗
PubMed2005

Overview on the analytical tools for quality control of natural product-based supplements: a case study of ginseng.

The quality of pharmaceutical products like ginseng is important for ensuring consumer safety and efficacy. Many ginseng products sold today are in various formulations such as powder, capsules, tablets, soft-gels, liquid extracts, and tea. This renders ginseng less identifiable by smell, taste, or physical appearance. Furthermore, as ginseng is expensive, adulteration with other cheaper products occurs. Hence quality assurance of ginseng is needed. This paper reviews the major techniques for ascertaining the level of ginsenosides, the primary active ingredients for ginseng, and covers high-performance liquid, gas, and thin-layer chromatographies, infrared and nuclear magnetic resonance spectroscopies, enzyme immunoassays, and other molecular methods. Supporting techniques such as ultraviolet, fluorescence, diode array and evaporative light scattering detections, and mass spectrometry will also be touched upon. This review also discusses the principles and applications of biosensors-in particular fiber optic-based sensors-and their feasibility in ginseng analysis based on preliminary studies. Despite their potential, there is currently no or limited commercial exploitation of fiber optic-based sensors to perform ginseng quality analysis. The opportunity for biosensors to be used for the rapid quality surveillance of ginseng is appealing, but several key issues still need to be addressed before they find widespread applications in the traditional Chinese medicine industry.

Biosensing Techniques↗
PubMed2002

Sense of taste in a new world monkey, the common marmoset: recordings from the chorda tympani and glossopharyngeal nerves.

Whole nerve, as well as single fiber, responses in the chorda tympani proper (CT) and glossopharyngeal (NG) nerves of common marmosets were recorded during taste stimulation with three salts, four acids, six bitter compounds and more than 30 sweeteners. We recorded responses of 49 CT and 41 NG taste fibers. The hierarchical cluster analysis distinguished three major clusters in both CT and NG: S, Q, and H. The S(CT) fibers, 38% of all CT fibers, responded only to sweeteners. The S(CT) fibers did not respond during stimulation with salts, acids, and bitter compounds but exhibited OFF responses after citric and ascorbic acids, quinine hydrochloride (QHCl), and salts (in 80% of S(CT) fibers). S(NG) fibers, 50% of all NG fibers, also responded to sweeteners but not to stimuli of other taste qualities (except for citric acid, which stimulated 70% of the S(NG) fibers). Some sweeteners, including natural (the sweet proteins brazzein, monellin) and artificial [cyclamate, neohesperidin dihydrochalcone (NHDHC), N-3,5-dichlorophenyl-N'-(S)-alpha-methylbenzylguanidineacetate (DMGA), N-4-cyanophenylcarbamoyl-(R,S)-3-amino-3-(3,4-methylenedioxyphenyl) propionic acid (CAMPA)] did not elicit responses in the S fibers. In general, the response profiles of the S(CT) and S(NG) clusters were very similar, the correlation coefficient between the responses to sweeteners in these clusters was 0.94. Both the Q(CT) and the Q(NG) fibers (40 and 46% of all fibers) were predominantly responsive to bitter compounds, although their responses to the same set of bitter compounds were quite different. Sweeteners with sweet/bitter taste for humans also stimulated the Q clusters. The H clusters (22 and 3% of all fibers) were predominantly responsive to acids and did not respond to stimuli of other taste qualities. However, bitter stimuli, mainly QHCl, inhibited activity in 70% of H(CT) fibers. Among a total of 90 fibers from both nerves there was only 1 NaCl-best fiber in CT. We found, however, that 35% of the CT fibers reacted to salts with inhibition of activity during stimulation, followed by an OFF response. This OFF response was diminished or eliminated by amiloride. These characteristics indicate that amiloride-sensitive sodium channels are involved in salt transduction in marmosets. In the two NG fibers responding to NaCl, we recorded neither suppression by amiloride nor OFF responses. Comparison of marmoset data with those of other nonhuman primates studied, rhesus and chimpanzee, demonstrates phylogenetic trends in the organization of taste system. This can help to uncover pathways of primate evolution.

Animals↗
PubMed2005

Improved hollow-core photonic crystal fiber design for delivery of nanosecond pulses in laser micromachining applications.

We report the delivery of high-energy nanosecond pulses (approximately 65 ns pulse width) from a high-repetition-rate (up to 100 kHz) Q-switched Nd:YAG laser through the fundamental mode of a hollow-core photonic crystal fiber (HC-PCF) at 1064 nm. The guided mode in the HC-PCF has a low overlap with the glass, allowing delivery of pulses with energies above those attainable with other fibers. Energies greater than 0.5 mJ were delivered in a single spatial mode through the hollow-core fiber, providing the pulse energy and high beam quality required for micromachining of metals. Practical micromachining of a metal sheet by fiber delivery has been demonstrated.

Crystallization↗
PubMed1995

Intestinal anastomosis healing in rat: collagen concentration and histochemical characterization by Picrosirius red staining and polarizing microscopy.

The study was designed to characterize collagen fibers in the healing intestinal anastomosis of rat by examining collagen concentration and recording the polarization colors of the collagen fibers in Picrosirius red-stained tissue sections. No significant changes in collagen concentration expressed by hydroxyproline content were noted at the anastomotic site at various postoperative time points. In the normal intestine, the predominant polarization colors were in the yellow to yellow-orange range, signifying tightly packed, matured collagen. During the first postoperative week, collagen fibers at the anastomotic region exhibited mainly polarization colors in the green to green-yellow range, implying less packed intermediate collagen fibers. After 2 weeks, collagen fibers at the anastomotic region gradually reacquired their preoperative polarizing texture. These findings strongly suggest that the "quality" rather than the quantity of collagen fibers plays an important role in maintaining the tensile strength of the healing intestinal anastomosis.

Anastomosis, Surgical↗
PubMed2007

Safety evaluation of large external fixation clamps and frames in a magnetic resonance environment.

Large orthopedic external fixation clamps and related components were evaluated for force, torque, and heating response when subjected to the strong electromagnetic fields of magnetic-resonance (MR) imaging devices. Forces induced by a 3-Tesla (T) MR scanner were compiled for newly designed nonmagnetic clamps and older clamps that contained ferromagnetic components. Heating trials were performed in a 1.5 and in a 3 T MR scanner with two assembled external fixation frames. Forces of the newly designed clamps were more than a factor 2 lower as the gravitational force on the device whereas, magnetic forces on the older devices showed over 10 times the force induced by earth acceleration of gravity. No torque effects could be found for the newly designed clamps. Temperature measurements at the tips of Schanz screws in the 1.5 T MR scanner showed a rise of 0.7 degrees C for a pelvic frame and of 2.1 degrees C for a diamond knee bridge frame when normalized to a specific absorption rate (SAR) of 2 W/kg. The normalized temperature increases in the 3 T MR scanner were 0.9 degrees C for the pelvic frame and 1.1 degrees C for the knee bridge frame. Large external fixation frames assembled with the newly designed clamps (390 Series Clamps), carbon fiber reinforced rods, and implant quality 316L stainless steel Schanz screws met prevailing force and torque limits when tested in a 3-T field, and demonstrated temperature increase that met IEC-60601 guidelines for extremities. The influence of frame-induced eddy currents on the risk of peripheral nerve stimulation was not investigated.

External Fixators↗
PubMed1997

[Lacrimal duct endoscopy. Report of initial experiences].

BACKGROUND: Until recently, we have had to depend on digital dacryocystography and on clinical examinations such as the fluorescein dye test, lacrimal probing and irrigation for diagnosis of disorders of the lacrimal system. Now the lacrimal system and its mucuos membranes can be viewed directly with a lacrimal endoscope. While the first endoscopes were rigid and limited by poor picture quality in axial illuminations, the new generation of endoscopes are a great leap forward for new diagnostic and therapeutic approaches. MATERIALS AND METHODS: A new lacrimal endoscopic system has been in used at the University Eye Clinic in Graz since January 1996. The outer diameter of the endoscopes are 0.5 and 0.3 mm. The endoscope produces high-quality images with 3000 picture fibers and 200 light fibers. The unit consits of xenon light sources, a three-chip videocamera and a monitor. RESULTS: Diagnostic endoscopic lacrimal probing was performed on 38 patients whose ages ranged from 8 months to 73 years. Canaliculus scars and strictures, obstructions at the entrance and exit of the lacrimal sac, and scars and structures of the lacrimal sac and nasolacrimal duct were diagnosed. CONCLUSION: Lacrimal endoscopy offers a new approach to the diagnosis of lacrimal disorders. Scars and relative obstructions can be identified more easily and can be directly opened with a laser or through mechanical probing. Perforations and massive mucosal injuries can be avoided. Further development of various types of lasers could allow for intracanalicular dacryocystorhinostomy, help prevent complications and increase the result.

Adolescent↗
PubMed1986

Reinnervation and recovery of cat muscle receptors after long-term denervation.

After nerve injury muscles remain denervated until axons return to begin reinnervation and recovery. The delay between injury and recovery in human limb nerves averages 13 weeks after crush, and 16 weeks after transection and suture. In order to assess the effects of such long denervation periods on the recovery of cat muscle receptors, we crushed the common peroneal nerve and denervated peroneus brevis for 10 to 134 days; 39 days were allowed for reinnervation in each experiment. After 50 days denervation, the mean number of terminal bands in the regenerated spindle primary endings was 10.3 compared with a normal mean of 29.0. After 134 days, the mean was 0.6 and spindles were severely atrophied. Despite this most spindle afferent fibers continued to respond normally to ramp-and-hold stretch, abnormal responses being recognized as those that failed to maintain firing during the held phase of the ramp. After 50 days, 21% of spindle afferent fibers responded abnormally and about this proportion did so after all the longer denervation periods. Maximum afferent firing rates were all significantly lower than normal, and many afferent fibers fatigued more rapidly. Tendon organs were atrophied after 113 and 134 days and received fewer terminals, but their afferents fired apparently normally during muscle twitch. These results imply that the consequences of long-term denervation on human muscle spindles would be unlikely to affect the overall pattern of response to stretch of any Ia or II afferent fibers reinnervating them, though the quality of their response might be impaired.

Afferent Pathways↗