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Biomedical subjects

A Ekblom

Publications and source records attributed to A Ekblom.

At least 55 records · Page 3Linked to original sources
PubMed1989

Some aspects of the experimental induction and measurement of itch.

Two different rating scales--a visual analogue scale (VAS) connected to a chart-recorder, and Pain-Track, a micro-computerized system with a 7-step-graded, fixed-point, non-verbal scale (FPNVS)--were evaluated for their capacity to assess experimental, histamine-induced itch continuously in 38 healthy subjects. The consequences for itch perception of using different injection sequences of various histamine concentrations were also investigated. A linear dose-response relationship was shown with random injection order for all subjective variables studied (itch latency and duration, maximal itch intensity, 'total itch index') with the VAS, but only for itch duration and 'total itch index' with the FPNVS. Using the VAS and injecting histamine solutions with increasing concentration, a significant dose-response curve was obtained for maximal itch intensity and 'total itch index', but when the same histamine stimuli were presented in the reverse (i.e. decreasing) order, there was no dose-response relationship. This indicates that central nervous system interaction may be unequally activated, depending on the order of different injected histamine stimuli. The objective variable flare was unaffected by the injection sequence. It is concluded that random injection order should be used in the assessment of itch sensation, in order to avoid systematic errors. The fact that the FPNVS did not discriminate as well as the VAS could indicate that our experimental stimuli were too weak to be properly discriminated with a 7-step-graded scale.

Adult↗
PubMed1988

Pain intensity measurements in patients with acute pain receiving afferent stimulation.

Six different pain rating scales, including a "pain relief scale", were compared in 80 patients suffering acute orofacial pain. Pain intensity measurements were made before and after a 30 min period of afferent stimulation (TENS/vibration and placebo). A good correlation was found between pain scores derived from the pain relief scale, visual analogue-, numerical- and graphic rating scales. The verbal rating scale did not perform well. The pain relief scale and the numerical rating scale are interesting alternatives to the established visual analogue scale.

Adolescent↗
PubMed1988

Does acute intraoral pain alter cutaneous sensibility?

Cutaneous sensibility was tested in eight patients suffering from acute postoperative intraoral pain. Tactile-, cold-, warm-, and heat-pain thresholds as well as reaction time to cold pulses were unaffected by the presence of pain. However, reaction time to warm pulses was increased in the painful area on the day of pain compared to a non-painful state. The findings are discussed in relation to (1) functional convergence of different sensory fibres on central neurons (2) the phenomenon of diffuse noxious inhibitory controls and (3) secondary hyperalgesia. The observed effect of clinical pain on the warm pathway could be explained as an intrasegmental noxious inhibitory effect.

Adolescent↗
PubMed1987

Is acupuncture sufficient as the sole analgesic in oral surgery?

Twenty-six patients who were undergoing operative removal of an impacted third molar were given acupuncture as an alternative to conventional local analgesia. Pain ratings during different stages of the surgical procedure showed that gingival and periosteal incisions were tolerated, with only minor pain experienced by 18 of the patients. During mucoperiosteal flap dissection 12 patients experienced unacceptable pain. In total, only 2 of the patients tolerated the entire procedure; however, they reported severe pain during the final part of the operation. In conclusion, it seems that acupuncture as performed in the present study could not subserve as a routine method for analgesia in this type of operative procedure.

Acupuncture Therapy↗
PubMed1987

Thermal sensitivity is not changed by acute pain or afferent stimulation.

The effect of conditioning stimulation on thermal sensitivity and clinical pain was studied in 40 patients and six healthy subjects. Thresholds regarding cold, warm and heat pain perception did not differ significantly between the painful and non-painful skin areas in patients or between patients and healthy subjects before stimulation. The patients received either 100 Hz TENS, 2 Hz TENS, 100 Hz vibration, or placebo. No significant changes in thermal sensitivity were observed during and after conditioning stimulation in any of the test groups, although 24/40 (60%) of the patients reported reduction of their clinical pain intensity. The results indicate that (a) thermal sensitivity is not influenced by the presence of clinical pain, (b) the effects of stimulation on thermal sensitivity (thresholds) and clinical pain are not closely related, (c) central inhibitory effects of TENS and vibration are crucial for their pain relieving capacity.

Adult↗
PubMed1986

Influence of naloxone on relief of acute oro-facial pain by transcutaneous electrical nerve stimulation (TENS) or vibration.

Twenty-eight patients suffering acute pain following operative removal of impacted third molars took part in the present study. In 20 patients who reported pain reduction exceeding 25% of the initial pain intensity during vibratory stimulation (100 Hz) or TENS (2 or 100 Hz), only 1 patient (given 2 Hz TENS) reported pain increase after injection of 0.8 mg naloxone (i.v.). In 8 patients, not treated with afferent stimulation, 2 experienced increase in pain intensity after naloxone injection. The results show that pain relief using TENS or vibration is not influenced by naloxone.

Acute Disease↗
PubMed1986

Influence of stimulus frequency and probe size on vibration-induced alleviation of acute orofacial pain.

The pain-relieving effect of vibratory stimulation, using different stimulus parameters, and placebo stimulation in acute orofacial pain is reported. The influence of 10-, 100-, and 200-Hz vibrations on pain reduction was studied in 96 patients; two different probe sizes were used. 54 out of 76 patients, receiving vibrations at any of the above frequencies, reported relief of pain to some extent, while only 6 out of 20 patients receiving placebo treatment experienced pain alleviation. No significant differences were found between the different frequencies and probe sizes used regarding the pain-relieving effect. However, placebo stimulation was significantly less effective than any kind of vibratory stimulation. Induction time for pain relief was significantly shorter using the larger probe as compared to using the smaller probe, regardless of frequency. The results indicate that the vibratory frequency (10-200 Hz) for activation of pain-inhibitory mechanisms is not critical in acute orofacial pain. Also, spatial summation from vibration-sensitive afferents seems to be of importance for a fast activation of the inhibitory systems.

Adolescent↗
PubMed1985

The influence of extrasegmental mechanical vibratory stimulation and transcutaneous electrical nerve stimulation on histamine-induced itch.

The effect of peripheral conditioning stimulation on experimentally induced pruritus was studied in 12 healthy volunteers. Itch was induced by intradermal injections of histamine on the upper arms. Vibration at 100 Hz and transcutaneous electrical nerve stimulation (TENS) at 2 and 100 Hz were applied extrasegmentally (dorsal aspect of the lower part of the leg, ipsilateral to the injected arm) for a period of 5 min following induction of itch. The effect of a 5 and 30 min stimulation period before itch elicitation was also studied as well as the influence of placebo stimulation. No significant effects were obtained with 100 Hz vibration and 100 Hz TENS, and none with placebo stimulation, whereas significant itch reduction was seen using 2 Hz TENS. The local skin flare response following histamine injections was not altered following conditioning stimulation of any type.

Adult↗
PubMed1984

Single and joint actions of noise and sinusoidal whole body vibration on TTS2 values and low frequency upright posture sway in men.

In the present study the changes in the TTS2 values and body upright posture sway were examined after exposure of subjects (n = 10) to stable broadband (white) noise (90 dB) alone, to sinusoidal vibration alone [directed vertically at the whole body (Z axis)], and to simultaneous exposure combinations of noise and vibrations of the same type. The frequency of the vibration was 5 Hz, but its acceleration was either 2.12 or 2.44 m/s2. There were six exposure combinations, and subsequently 60 tests were carried out in an exposure chamber. One test consisted of a control period of 30 min, of three consecutive exposure periods of 16 min each and of a recovery period of 15 min. After the three exposure combinations which included noise, half of the subjects were exposed to vibration during the recovery period. Apart from indicating an increase in the temporary hearing threshold, the results showed that simultaneous exposure to noise and vibration increases the instability of the body upright posture. The TTS2 values at the 4 and 6 kHz frequencies increased considerably more rapidly when the subjects were exposed simultaneously to noise and vibration than when exposed to noise alone. Without exception, the TTS2 values increased most during the first exposure period. It was noteworthy that exposure to vibration during the recovery period accelerated the recursion of the TTS2 values, especially in cases where the subjects had been exposed to noise alone. The variance of the body sway amplitudes and the standard deviation increased within the frequency range 0.063-2.000 Hz owing to noise alone and simultaneous noise and vibration. In the directions X and Y, within the frequency ranges 0.063-0.100 Hz and 0.100-0.600 Hz, the means of the maximum amplitudes of body sway increased especially in connection with those tests in which the subjects had been simultaneously exposed to noise and vibration.

Adult↗
PubMed1984

A thin-section and freeze-fracture study of the pulp blood vessels in feline and human teeth.

The fine structure of blood vessels with a diameter of less than 50 micrometers, i.e. small arterioles, capillaries and postcapillary venules were studied. The number of pinocytotic vesicles was greater in capillary endothelium than in arterioles and venules. There was regional variation in vesicle frequency in capillary endothelial cells (arteriolar and venule cells not studied). Fenestrations and pinocytotic vesicles were closely associated in some capillary-endothelial membrane areas and segmental differentiation of tight junctions (zonula occludens) in the vascular endothelium. The arteriolar tight junctions were classified as relatively tight, capillary junctions as leaky and venule junctions as very leaky. No nexuses (gap junctions) were found in the endothelium. Only four nexuses were found in the arteriolar smooth-muscle cells. Perivascular fibrocytes were frequently interconnected with nexuses. Nerve fibres in the vicinity of blood vessels contained granular and clear vesicles. The narrowest gap between vesicle-containing nerves and smooth-muscle cells was 0.3 micrometer. No specialized contacts were found between nerve fibres and vascular cells. Solitary cilia with a 9 + 0 pattern were occasional in capillary endothelial cells fibroblasts and odontoblasts. Only one arterio-venous anastomosis was found.

Adolescent↗
PubMed1984

The influence of mechanical vibratory stimulation and transcutaneous electrical nerve stimulation on experimental pruritus induced by histamine.

The effect of conditioning mechanical vibratory stimulation and transcutaneous electrical nerve stimulation (TENS) on experimentally induced pruritus was studied on 12 healthy subjects. Pruritus was provoked by intradermal injection of histamine on the upper arm. Vibration at 10, 100 and 200 Hz and TENS at 2 and 100 Hz were applied (i) over or (ii) proximal (in the same dermatome) to the pruritic area for a period of 5 min following itch elicitation. In addition the influence of a 5 min pre-stimulatory regimen of the injection area was investigated (iii). The results obtained were compared with unconditioned values and with those obtained following a placebo conditioning procedure (i, ii). It was found that vibratory as well as electrical stimulation, for all frequencies used, reduced subjective itch intensity. Vibration at 100 Hz was the most effective mode of stimulation especially when applied directly to the pruritic area. Conditioning with 100 Hz vibration was also the most effective mode for reducing the duration of the itch response as well as the total experience of pruritus (estimated as a total itch index). Induction time to partial and maximal itch alleviation was shortest for 100 Hz vibration. The results indicate that treatment of pruritic conditions with conditioning stimulation, especially vibration, may be of therapeutic interest.

Adult↗
PubMed1983

Transcutaneous electrical nerve stimulation (TENS) as compared to placebo TENS for the relief of acute oro-facial pain.

The present paper describes the effect of high frequency, low frequency and placebo TENS on acute oro-facial pain in 62 patients, attending to an emergency clinic for dental surgery; they had all suffered pain for 1-4 days. The patients were randomly assigned to one of three groups receiving either high frequency (100 Hz), low frequency (2 Hz) or placebo TENS. In the two groups receiving TENS (42 patients) 16 patients reported a reduction in pain intensity exceeding 50%; out of these 16 patients, 4 patients reported complete relief of pain. In the placebo group (20 patients) 2 patients reported a pain reduction of more than 50%; out of these 2 patients, none reported a complete pain relief. Mechanical vibratory stimulation augmented the pain reduction obtained by TENS in 5 out of 10 patients.

Adult↗
PubMed1982

Effects of conditioning vibratory stimulation on pain threshold of the human tooth.

The effect of mechanical vibratory stimulation on the human tooth pain threshold has been studied in 4 healthy naïve subjects. Vibration at 10 and 100 Hz was applied to a maxillary incisor and the electrical pain threshold was measured in an adjacent tooth. During the conditioning stimulation the pain threshold increased 1.2-1.8 times the unconditioned values. The present study indicates that mechanical vibratory stimulation applied to human teeth elevates the pain threshold in adjacent teeth.

Adult↗
PubMedDate not supplied

Ultrastructural and electrophysiological changes in the olfactory epithelium following exposure to organic solvents.

The present study describes some effects on frog olfactory mucosa following acute exposure to styrene and toluene, two organic solvents. The olfactory summed receptor potential (EOG) was recorded in order to monitor the functional effect. The olfactory epithelium was examined with transmission electron microscopy, using both thin section and freeze-fracture technique. The ultrastructural changes in the olfactory epithelium following exposure to the solvents were mainly of two types: (1) an increased secretion from the sustentacular cells, (2) membrane fusion of the cilia, sometimes with a loosening of the ciliary membrane. The tight junctional complex between the receptor and sustentacular cells at the epithelial surface remained intact. The EOG amplitude generally showed some degree of reduction following exposure, with a gradual recovery towards pre-exposure values.

Animals↗