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PubMed1962

Centrioles and the formation of rudimentary cilia by fibroblasts and smooth muscle cells.

Cells from a variety of sources, principally differentiating fibroblasts and smooth muscle cells from neonatal chicken and mammalian tissues and from organ cultures of chicken duodenum, were used as materials for an electron microscopic study on the formation of rudimentary cilia. Among the differentiating tissues many cells possessed a short, solitary cilium, which projected from one of the cell's pair of centrioles. Many stages evidently intermediate in the fashioning of cilium from centriole were encountered and furnished the evidence from which a reconstruction of ciliogenesis was attempted. The whole process may be divided into three phases. At first a solitary vesicle appears at one end of a centriole. The ciliary bud grows out from the same end of the centriole and invaginates the sac, which then becomes the temporary ciliary sheath. During the second phase the bud lengthens into a shaft, while the sheath enlarges to contain it. Enlargement of the sheath is effected by the repeated appearance of secondary vesicles nearby and their fusion with the sheath. Shaft and sheath reach the surface of the cell, where the sheath fuses with the plasma membrane during the third phase. Up to this point, formation of cilia follows the classical descriptions in outline. Subsequently, internal development of the shaft makes the rudimentary cilia of the investigated material more like certain non-motile centriolar derivatives than motile cilia. The pertinent literature is examined, and the cilia are tentatively assigned a non-motile status and a sensory function.

Animals↗

PubMed1996

Oxygen sensing by ion channels and chemotransduction in single glomus cells.

We have monitored cytosolic [Ca2+] and dopamine release in intact fura-2-loaded glomus cells with microfluoroimetry and a polarized carbon fiber electrode. Exposure to low PO2 produced a rise of cytosolic [Ca2+] with two distinguishable phases: an initial period (with PO2 values between 150 and approximately 70 mm Hg) during which the increase of [Ca2+] is very small and never exceeds 150-200 nM, and a second phase (with PO2 below approximately 70 mm Hg) characterized by a sharp rise of cytosolic [Ca2+]. Secretion occurs once cytosolic [Ca2+] reaches a threshold value of 180 +/- 43 nM. The results demonstrate a characteristic relationship between PO2 and transmitter secretion at the cellular level that is comparable with the relation described for the input (O2 tension)output (afferent neural discharges) variables in the carotid body. Thus, the properties of single glomus cells can explain the sensory functions of the entire organ. In whole-cell, patch-clamped cells, we have found that in addition to O2-sensitive K+ channels, there are Ca2+ channels whose activity is also regulated by PO2. Ca2+ channel activity is inhibited by hpoxia, although in a strongly voltage-dependent manner. The average hypoxic inhibition of the calcium current in 30% +/- 10% at -20 mV but only 2% +/- 2% at +30 mV. The differential inhibition of K+ and Ca2+ channels by hypoxia helps to explain why the secretory response of the cells is displaced toward PO2 values (below approximately 70 mm Hg) within the range of those normally existing in arterial blood. These data provide a conceptual framework for understanding the cellular mechanisms of O2 chemotransduction in the carotid body.

Action Potentials↗

PubMed1989

Respiratory patterns associated with swallowing: Part 2. Neurologically impaired dysphagic patients.

The co-ordination of respiration and swallowing was recorded electronically in three groups of patients who complained of dysphagia following a stroke, or associated with multiple sclerosis or motor neurone disease. The test used was simple and the equipment easily taken to the patient, in bed if necessary. All the patients showed differences from normal subjects and there were differences between each of the neurologically impaired groups. The technique appears to allow an assessment of the state of oropharyngeal motor and sensory functions separately during swallowing.

Adolescent↗

PubMed1978

The psychophysics of taste.

Modern psychophysical studies of sensory systems have produced new insight into sensory function and new techniques that have application to the clinical evaluation of taste. Most previous taste evaluation has been done with threshold measures that are subject to a variety of problems and that also fail to provide an accurate picture of suprathreshold sensitivity. The scaling of suprathreshold intensity reflects a patient's taste world more accurately than thresholds.

Citrates↗

PubMed2006

Treatment of alcoholic polyneuropathy with vitamin B complex: a randomised controlled trial.

AIMS: To evaluate the therapeutic efficacy and safety of BEFACT Forte 'new formulation' and BEFACT Forte 'old formulation' in the treatment of sensory symptoms of alcoholic polyneuropathy. METHODS: A multi-centre, randomised, double-blind, placebo-controlled study was conducted on 325 patients with sensory symptoms and signs of alcoholic polyneuropathy. Patients were randomised to the 'old formulation' (i.e. vitamins B1, B2, B6, and B12), 'new formulation' [i.e. identical to the 'old formulation' with additional folic acid (vitamin B9)], or placebo in a 1:1:1 ratio. One tablet of the study medication ('new formulation' or 'old formulation') or placebo was taken orally, three times a day, over a 12-week treatment period. RESULTS: Therapeutic efficacy was assessed in 253 patients by measuring vibration perception threshold (biothesiometry), intensity of pain, sensory function, co-ordination, and reflex responses. Patients treated with the 'new formulation' or 'old formulation' showed significant improvement in the primary efficacy endpoint (vibration perception threshold at the big toe) and secondary efficacy endpoints in comparison to placebo. The active treatment groups were comparable to placebo in terms of safety. CONCLUSIONS: A specific vitamin B complex (with and without folic acid) significantly improved symptoms of alcoholic polyneuropathy over a 12-week treatment period.

Alcoholic Neuropathy↗

PubMed1995

Weight judgment. The discrimination capacity of a deafferented subject.

A weight discrimination study was undertaken to test (i) the capacity of controls and a deafferented subject (deprived of large sensory myelinated fibres from nose down), to discriminate weights with and without vision; (ii) the capacities of observers to discriminate weights while watching the deafferented and control subjects' lifting movements; (iii) the contribution of supplementary sources of sensory information (e.g. vestibular afferents) to the deafferented subject's discrimination capacity. With vision, G.L.'s liminal discrimination of weights was similar to that of the controls. In contrast, precluding vision impaired massively, but not completely, G.L.'s discrimination capacity, so emphasizing the importance of visual kinaesthetic cues in G.L. and incidently the importance of large myelinated sensory function in weight discrimination in controls. Kinematics recordings of G.L.'s lifting movements with vision revealed a significant correlation between weight and peak velocity of the lifting movement. This reflects a specific strategy used by G.L. to generate movements, allowing her to judge the weight of a lifted object visually. Peak velocity rather than amplitude of movement appears to be the main cue for G.L. since there was a lack of correlation between amplitude and weight lifted. For controls, none of the correlations (weight versus amplitude or weight versus velocity) was significant, whether vision was available or not. When watching G.L.'s lifting performance, external observers were able to use similar cues to establish their judgments, but they were far less accurate in doing so when watching control subjects. This suggests that controls were using a strategy different from G.L.'s.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2004

Three exercise paradigms differentially improve sensory recovery after spinal cord contusion in rats.

Spinal cord injury (SCI) induces incapacitating neuropathic pain in the form of allodynia-a painful response to normally non-noxious stimuli. Unfortunately, the underlying mechanisms of these sensory changes are not well understood, and effective treatments for allodynia have proven elusive. We examined whether physical exercise can improve sensory function after experimental SCI by promoting neurotrophin expression in the spinal cord and periphery, which modulates synaptic transmission and function. Female rats with moderate spinal cord contusion participated in treadmill training, swim training, stand training or were untrained. Exercise training began 4 days post surgery, lasted 20-25 min per day, 5 days a week for 7 weeks. Allodynia, as measured using von Frey hairs of different bending forces to the plantar hind paw, developed in the untrained group 3 weeks after SCI. Treadmill training ameliorated allodynia and restored normal sensation by 5 weeks. Swim training had a transient beneficial effect, but allodynia returned by 7 weeks. Stand training had no effect. Resolution of allodynia after treadmill training was associated with normal mRNA levels of brain-derived neurotrophic factor (BDNF) in both the lumbar spinal cord and soleus muscle. No other exercise paradigm restored BDNF centrally and peripherally. Greater recovery from allodynia correlated significantly with the degree of normalization of central and peripheral BDNF levels. These findings suggest that rhythmic, weight-bearing exercise may be an effective intervention to counter SCI-induced allodynia.

Animals↗

PubMed2003

Creating a coherent set of indicators to monitor health across Europe: the Euro-REVES 2 project.

The Euro-REVES 2 project, 'Setting up of a coherent set of health expectancies for the European Union', was begun in 1998 under the European Health Monitoring Programme with the aim of selecting a concise set of instruments to simultaneously monitor mortality and the different facets of health. An in-depth analysis of the current health survey instruments in Europe together with a review of past research, found that, although harmonization in instruments appeared to exist superficially, major differences existed. Four instruments have been recommended (where necessary using existing instruments with modifications suggested by the research literature) covering physical and sensory functional limitations, activity restriction, self-perceived health and mental health. Additionally a new global activity limitation indicator (GALI) has been developed. These instruments are firmly anchored to past research and the health concepts behind the indicators and their relevance to policy and guidelines for implementation are explicitly made. The second phase of the project will recommend further instruments, leading to health expectancies that cover all the conceptual framework of population health measurement. This will allow assessment of health inequalities between the European Union countries, an appreciation of the causes and the production of profiles for each country in terms of the various facets of health.

Activities of Daily Living↗

PubMed1996

Integument and sensillum auriforme of the opisthosoma of Rhipicephalus appendiculatus (Acari:Ixodidae).

The opisthosomal integument and sensilla auriformia of Rhipicephalus appendiculatus Neumann larvae, nymphs, females and males, both unfed, fed, and during molt, were examined by light and electron microscopy in relation to semiochemical production. The integument consists of epidermis, endocuticle, exocuticle, epicuticle, a superficial wax layer and a variable additional deposit. The integument of immature instars and females grows greatly during feeding. The integument is traversed by pore canals from the epidermis to the outer wax canals. The epidermis can secrete material to the exterior by way of the pore canals and wax canals. The sensillum auriforme is a common disk-shaped organ, with a complex internal chamber open to the exterior by way of a pore. It has no apparent secretory capacity and is of presumed sensory function. It is located in the integument of scutum and alloscutum of all instars.

Animals↗

PubMed1999

Ultrastructure of taste receptor cells in active and hibernating ground squirrels.

Differences in taste bud ultrastructure between active and low-temperature hibernation states were investigated in the Siberian ground squirrel, Citellus undulatus. Compared to active summer animals, taste bud volume and the morphology of the taste pore showed little change while an animal was hibernating. However, impressive differences were observed in nuclei and cytoplasmic organelles of all cells within taste buds. In low-temperature hibernation the nucleoli of elongated, non-dark cells had few, but large, fibrillar centres, a sign of inactivity. In the cytoplasm, the number of free polyribosomes (polysomes) was sharply decreased; ribosomes were seen mainly as (non-synthesizing) monosomes and more seldom as membrane-associated ribosomes. Profiles of endoplasmic reticulum (ER) were reduced, to the extent that only separate and rare cisternae of smooth and rough ER remained. The large vacuoles, which are typically found in many taste cells of active animals, were absent during hibernation, and the Golgi apparatus appeared to be disassembled into numerous vesicles. Of these, many had small diameters near 60 nm, while a few had larger diameters near 300 nm. Secretory organelles (dense granules in dark cells and dense-cored vesicles in type III cells) were rare during hibernation, the lateral plasma membrane was smooth, and signs of exocytosis were not found. These changes suggest reduced protein synthesis and reduced sensory function during hibernation.

Animals↗

PubMed1977

Objective determinations of sensibility in the upper extremity. Part I. Median nerve sensory conduction velocities.

Distal sensory conduction velocities were determined in 109 normal median nerves. A significant decrease in sensory conduction velocity was noted with increasing age. Latencies increased with age but this relationship was not significant in men. Variables which contribute to the wide range of normal conduction velocities are discussed, and the need for each clinician to establish his own testing procedure is stressed. An additional method for assessing sensory function is suggested.

Adult↗

PubMed2005

Laryngeal and velopharyngeal sensory impairment in obstructive sleep apnea.

STUDY OBJECTIVE: To determine whether mucosal sensory dysfunction is present at multiple upper-airway sites in patients with obstructive sleep apnea (OSA). DESIGN: Physiologic testing of consecutive patients with OSA and nonsnoring controls. SETTING: University hospital sleep center. PARTICIPANTS: Thirty-nine subjects with OSA and 17 controls. INTERVENTIONS: Endoscopic testing was used to determine sensory detection thresholds for air-pressure pulses delivered to the oropharynx, velopharynx, hypopharynx, and larynx (aryepiglottic eminence). The air-pulse stimulus intensity required to elicit the protective laryngeal adductor reflex was also determined. MEASUREMENTS AND RESULTS: There was a significant impairment in sensory detection threshold for OSA versus control subjects in the oropharynx, as previously described by ourselves using other techniques, as well as at the velopharynx (median 11 mm Hg [confidence interval 9-11] for subjects with OSA vs 8 mm Hg [confidence interval 4-11] for controls, P = .03) and, at the larynx, 4 mm Hg [confidence interval 2-9] for subjects with OSA vs 2 mm Hg [confidence interval 2-3] for controls, P < .001). The threshold stimulus intensity for the laryngeal adductor reflex was also significantly higher for OSA subjects. For OSA patients with abnormal laryngeal sensation (61% of OSA subjects), there were significant correlations between laryngeal sensory values and measures of apnea severity, including apnea-hypopnea index (r = 0.82, P < .001) and nadir SaO2 (r = -0.48, P < .05). CONCLUSION: Mucosal sensory function is impaired at multiple upper-airway sites in OSA.

Adult↗

PubMed1990

Disorder of the inhibitory glycine receptor: inherited myoclonus in Poll Hereford calves.

Inherited congenital myoclonus in Poll Hereford calves is characterized by hyperesthesia and myoclonic jerks of the skeletal musculature that occur spontaneously and in response to sensory stimuli. The symptoms of the disorder suggest a failure of spinal inhibition and are similar to those in subconvulsive strychnine poisoning. Strychnine is a high-affinity antagonist of the synaptic actions of glycine. Our recent biochemical studies revealed a specific and marked deficit in [3H]strychnine binding sites in brain stem and spinal cord membranes from myoclonic calves compared with unaffected controls, reflecting a decrease in inhibitory glycine receptors. Glycine is a major inhibitory neurotransmitter in the mammalian central nervous system, and glycinergic transmission is important for the control of both motor and sensory functions in the spinal cord. In other studies, synaptosomes prepared from affected spinal cord showed a significantly increased ability to accumulate [3H]glycine, indicating an increased capacity of the high-affinity neuronal reuptake system for glycine. In contrast, spinal cord glycine concentrations and stimulus-induced release of endogenous glycine, measured in vitro, were unaltered. The major clinical signs of this myoclonic disorder can be explained by the reported deficiency of inhibitory glycine receptors in brain stem and spinal cord, and future research will be directed toward identifying the nature of the genetic alteration responsible for this deficiency. The characteristics of this bovine receptor abnormality are similar to those described for the mutant spastic mouse.

Animals↗

PubMed1996

Motor and sensory disability has a strong relationship to induction dose of thiopental in patients with the hypertropic variety of Charcot-Marie-Tooth syndrome.

In a prospective study, we determined the anesthetic induction dose of thiopental and the clinical variables influencing the appropriate induction dose of thiopental in 20 patients with the hypertrophic variety of Charcot-Marie-Tooth syndrome (CMT). As controls we chose 50 patients without CMT. Motor disturbance was evaluated in terms of muscle weakness of the distal lower and upper extremities. We examined sensory disturbance by evaluating loss of sensation in the index finger and great toe. The preinduction cardiac output was measured by echocardiography. Anesthesia was induced with repeated injections of 50 mg thiopental. The minimum induction dose of thiopental (MID) was confirmed when the eyelash reflex ceased. We maintained anesthesia with enflurane and nitrous oxide. The 95% confidence interval of the MID in patients used as the controls was 2.5-4.9 mg/kg. The MID in 11 patients with CMT was less than 2.5 mg/kg. MIDs in the patients with CMT were significantly smaller than those of the control patients (P < 0.0001). Also we found a strong relationship between the MID and the severity of both motor and sensory disturbances (P = 0.003 and 0.002, respectively). There was no relationship between the MID and other clinical variables, such as age, gender, inherited type, body weight, and preinduction cardiac output. Because delay in the recovery from anesthesia can be caused by an inappropriate dose of thiopental in CMT patients in whom motor and sensory function is seriously impaired, the dose of thiopental probably should be reduced and based on the individual patient's response.

Adolescent↗

PubMed1997

Neurologic evaluation of infant and adult rats before and after sciatic nerve blockade.

BACKGROUND: Only limited data exist comparing differences in sensory function and responses to neural blockade in infant and adult rats. Therefore, the authors sought (1) to compare baseline thermal, proprioceptive, and postural responses in infant, adolescent, and adult rats; and (2) to compare the effects of sciatic nerve blockade on thermal, proprioceptive, and postural responses in infant, adolescent, and adult rats. METHODS: Infant, adolescent, and adult rats were evaluated for proprioceptive, thermal, and mechanical nociceptive and motor function before and after sciatic blockade using a detailed neurologic examination. RESULTS: Mechanical and thermal nociception were present in all rats, starting from age 1 day. The withdrawal reflex latency to pinch was rapid at all ages, whereas that reaction to thermal stimulus depended on both age and temperature. In contrast, the tactile placing response and hopping response were absent at birth and developed completely during the first 10 days of life. The extensor postural thrust was absent in the first 2 weeks of life and developed variably during the first 50 days of life. Sciatic blockade duration is shorter in infant rats than in adult rats receiving the same dose per kilogram. A brief halothane general anesthetic at the time of sciatic injection in infant or adult rats does not alter the duration of blockade. CONCLUSIONS: Infant rats show increased sensitivity to noxious thermal stimuli and similar response to deep mechanical stimuli compared with adult rats. Their proprioceptive and motor responses develop during the first 2 weeks of life. When doses are scaled by body weight, block duration is shorter in infant than in adult rats.

Age Factors↗

PubMed1989

Nerve endings in palm skin grafts.

We examined regeneration of Meissner corpuscles in palm skin grafts. In only one of the specimens (split-thickness skin graft from the sole of the foot), numerous regenerated Meissner corpuscles were found in the dermal papilla. This suggests that the nerve pattern of the graft depends on reinnervation from the recipient site and the regeneration of encapsulated nerve endings contained in the graft. It is recommended that skin grafts containing the encapsulated nerve endings be used in digits to obtain a satisfactory recovery of the sensory function.

Adolescent↗

PubMed1995

Treatment of hyperesthetic neuropathic pain in diabetics. Decompression of the tarsal tunnel.

OBJECTIVE: The authors evaluated the causal relationship between entrapment of the posterior tibial nerve and neuropathic pain and describe the results of nerve decompression in a selected group of patients with intractable pain. SUMMARY BACKGROUND DATA: Painful metabolic neuropathy has, until recently, been thought to be an irreversible and essentially untreatable complication of diabetes. Recent studies have shown that metabolic deterioration is only one component of the disease process. METHODS: A group of patients with intractable painful neuropathy and a positive percussion sign underwent posterior tibial nerve decompression. RESULTS: Nerve decompression relieved the pain in the majority of treated patients. Return of other sensory function also was noted. CONCLUSIONS: Painful diabetic neuropathy of the lower extremities is potentially reversible. It appears to be caused partially by nerve entrapment and can be reversed by decompression.

Adult↗

PubMed2002

Reinnervation of a single vibrissa after nerve excision in the adult rat.

After a survival time of 180 days following the excision of a 2 mm segment of the vibrissal nerve to the gamma straddler vibrissa in the adult rat, a retrograde fluorescent single-labelling experiment revealed that 46% of the injured vibrissal sensory neurones had regenerated their peripheral processes. Peripheral collateral sprouting was not involved in the reinnervation of the denervated gamma vibrissa, as proved by a retrograde fluorescent double-labelling experiment. The regenerating nerve fibres did not invade the intact neighbouring vibrissae of the gamma vibrissa, and the sensory nerve fibres of the intact vibrissae were not translocated to the denervated gamma vibrissa. Thus, the sensory function of the denervated gamma vibrissa was restored exclusively by the regeneration of the damaged vibrissal nerve.

Animals↗