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PubMed2003

Dietary intake of the flower extracts of German chamomile (Matricaria recutita L.) inhibited compound 48/80-induced itch-scratch responses in mice.

The antipruritic effects of the diets containing German chamomile on the compound 48/80-induced scratching in ddY mice were examined. Since it is reported that an injection of compound 48/80, but not histamine, induced scratching behaviour due to itch but not to pain in ddY mice (Kuraishi et al., 1995), compound 48/80-induced scratching in ddY mice seems to be a suitable parameter for evaluating antipruritic agents independent of histamine receptor antagonism. In the mice fed the diet containing 1.2 w/w % of the ethyl acetate extract of dried flower of German chamomile (Matricaria recutita L.) for 11 days, the compound 48/80-induced scratching behaviour was significantly suppressed. The ethyl acetate extract of German chamomile dose dependently suppressed compound 48/80-induced scratching without affecting body weight increase. The ethyl acetate fraction of the ethanol extract and the ethanol extract of hot water extraction residue of German chamomile flower also showed strong inhibition on the compound 48/80-induced scratching. The inhibitory effects of the dietary intake of the German chamomile extracts on compound 48/80-induced itch-scratch response were comparable to oxatomide (10 mg/kg, p.o.), an anti-allergic agent.

Animals↗

PubMed1996

An infrared video camera system to observe nocturnal scratching in atopic dermatitis patients.

We used an infrared video camera and video tape recorder system to record and analyze nocturnal scratching in seven patients with atopic dermatitis (AD) and three non-itchy healthy controls. The patterns and the locations of scratching were successfully observed. Scratching bouts lasting more than 5 sec were counted, and the summation of the duration of all the scratching bouts (total scratching time, TST) was used as an index of nocturnal scratching. TST in patients with AD turned out to be some hundreds to ten thousands of seconds; the TST in controls was between zero and a hundred seconds. The infrared video camera system measured nocturnal scratching simply and reliably without disturbing the patients' sleep.

Adolescent↗

PubMed2006

Induction of scratching behaviour and dermatitis in various strains of mice cohabiting with NC/Nga mice with chronic dermatitis.

BACKGROUND: NC/Nga (NC) mice with similar pathological and behavioural features as seen in human atopic dermatitis are used as a model of the disease. Under normal circumstances, spontaneous and persistent scratching occurs in NC mice and this can lead to the onset of skin inflammation. OBJECTIVES: We examined the induction of scratching behaviour in NC, BALB/c, ICR and C3H/HeN mice, and of dermatitis in NC and BALB/c mice, by cohabitation with mice with dermatitis. METHODS: NC, BALB/c, ICR and C3H/HeN mice were kept together with NC mice with chronic dermatitis (CNV-NC) for 2 weeks, and the numbers of scratching episodes were counted. NC and BALB/c mice were also kept together with CNV-NC mice for 24 weeks and the skin severity score was assessed. The score was assessed for a further 8 weeks after separation of these mice. RESULTS: The number of scratching episodes in NC, BALB/c, ICR and C3H/HeN mice was increased by cohabitation with CNV-NC mice. Cohabitation with CNV-NC mice led to dermatitis in both NC and BALB/c mice. The number of scratching episodes and the skin severity score in BALB/c mice were about half of those in NC mice. When cohabitation with CNV-NC mice stopped, the number of scratching episodes and the skin severity score decreased in BALB/c mice, but not in NC mice. Changes in the histopathological data of BALB/c mice supported the severity of skin inflammation. CONCLUSIONS: Our study demonstrates that scratching behaviour and dermatitis can be induced in various strains of mice by cohabitation with CNV-NC mice, and that cessation of cohabitation leads to a recovery in BALB/c mice but not in NC mice.

Animals↗

PubMed1997

Chronic UVA (365-nm) irradiation induced scratching in hairless mice: dose-time dependency and the effect of ketanserin.

In a study on the dose-response relationship for longwave UVA (UVA1; 340-400 nm) carcinogenesis in hairless mice scratch marks appeared after months of daily exposure as an unwanted side effect. Tumor induction in the highest of the 4 tested dose groups (receiving a daily dose of 430 kJ/m2 of 365-nm radiation) could not be determined because extensive scarification occurred prior to the development of any tumors. The induction of scratch marks could be scored and quantified in all 4 dose groups tested. The UVA1 dose-dependencies for the induction of tumors and scratch marks were compared. We found that the induction of scratch marks depended mainly on the cumulative UVA1 exposure, whereas tumor induction showed a lesser dose-dependency. An attempt was made to prevent the apparent pruritogenic effect of UVA1 irradiation and to understand its mechanism. The influence of ketanserin, a serotonin/histamine antagonist, on the UVA1 induction of scratch marks was tested in groups of 8 mice daily irradiated with 430 kJ/m2. No difference was found between treated and untreated animals. Histological examination of skin biopsies from irradiated mice from the 430-kJ/m2 dose group from the UVA1 carcinogenic experiment, showed no changes in numbers of mast cells or other inflammatory features when compared to skin biopsies from unirradiated control mice. This indicated that UVA1-induced scratching is not mediated through mast cell release of serotonin and/or histamine. An adequate therapeutic treatment which can prevent UVA1-induced scratching would enable us to test tumor induction with UVA1 over a larger dose range, and may provide additional insight in how this radiation damages the skin. It remains conjectural whether there exists an analogous UVA-induced pruritus in human skin.

Animals↗

PubMed2005

Scratching behavior in spontaneous- or allergic contact-induced dermatitis in NC/Nga mice.

NC/Nga mice have pathological and behavioral features similar to those seen in human atopic dermatitis. There are two known dermatitis models in NC/Nga mice, one being spontaneous-induced dermatitis under conventional conditions and the other 2,4,6-trinitrochlorobenzene (TNCB)-induced allergic contact dermatitis. However, there are significant differences in time course on development of dermatitis. We studied the role of scratching behavior (sign of itch) on the development of dermatitis on spontaneous- and TNCB-induced dermatitis. We measured scratching counts, transepidermal water loss (TEWL), and skin inflammation score, under conventional conditions or by applying 5% TNCB once a week for 6 weeks in NC/Nga mice. In spontaneous-induced dermatitis, scratching counts increased with the passage of time. The scratching counts were significantly increased only 1 week after housing the mice under conventional conditions, but no changes were observed in cases of TNCB-induced dermatitis. In spontaneous-induced dermatitis, TEWL and skin-inflammation score were gradually increased, time-dependently. On the other hand, in TNCB-induced dermatitis, these dependent values rapidly increased and reached a maximum only after 24 h TNCB application. These data suggest that pathogenesis of spontaneous- and allergic contact-induced dermatitis was clearly different. It will be of major interest to identify the pruritic mediators causing profound scratching behavior and scratching-induced aggravation of inflammation in the spontaneous-induced dermatitis, as opposed to the inflammatory mediators that cause contact allergic dermatitis without major scratching.

Animals↗

PubMed2005

Activity of the motor cortex during scratching.

In awake cats sitting with the head restrained, scratching was evoked using stimulation of the ear. Cats scratched the shoulder area, consistently failing to reach the ear. Kinematics of the hind limb movements and the activity of ankle muscles, however, were similar to those reported earlier in unrestrained cats. The activity of single neurons in the hind limb representation of the motor cortex, including pyramidal tract neurons (PTNs), was examined. During the protraction stage of the scratch response, the activity in 35% of the neurons increased and in 50% decreased compared with rest. During the rhythmic stage, the motor cortex population activity was approximately two times higher compared with rest, because the activity of 53% of neurons increased and that of 33% decreased in this stage. The activity of 61% of neurons was modulated in the scratching rhythm. The average depth of frequency modulation was 12.1 +/- 5.3%, similar to that reported earlier for locomotion. The phases of activity of different neurons were approximately evenly distributed over the scratch cycle. There was no simple correlation between resting receptive field properties and the activity of neurons during the scratch response. We conclude that the motor cortex participates in both the protraction and the rhythmic stages of the scratch response.

Animals↗

PubMed1978

Generation of scratching. II. Nonregular regimes of generation.

1. The activity of muscle nerves and that of spinal interneurons from the L4 and L5 segments was recorded during fictitious scratching (5), which was evoked in decerebrate curarized cats by stimulation of the cervical spinal cord. In some experiments, rhythmical generation was disturbed by stimulation of the fifth lumbar dorsal root (DL5). 2. Excluding the very beginning of scratching, rhythmical generation was usually rather regular: fluctuations of the cycle duration were less than +/-5%. But changes in the stimulation strength, in the stimulating electrode position, and in the hindlimb position led to changes of the generation regime. In different regimes, the mean value of the cycle duration could differ by 20-30%. No correlation was found between mean durations of flexor and extensor phases for different regimes. 3. Rhythmical generation was possible only if the hindlimb was put to "scratch posture," i.e., deflected forward. Generation immediately stopped when the limb was deflected backward, and immediately started when it was returned to scratch posture. 4. In some experiments, stimulation of the cervical spinal cord first resulted in generation of slow oscillations with the temporal pattern typical of stepping (cycle duration about 500 ms, flexor and extensor phases being almost equal to each other). Then, during 5-20 cycles, gradual transition to a normal scratch cycle (about 250 ms) occurred mainly due to considerable shortening (5-10 times) of the extensor phase. In some experiments, considerable spontaneous variations of the flexor phase were observed, while the extensor phase was constant. 5. A single stimulus applied to DL5 considerably affected the cycle duration. Repetitive DL5 stimulation,with a rhythm close to that of scratching, resulted in synchronization of the spinal generator by the stimuli. 6. Spinal interneurons recorded during transition from slow oscillations to a normal scratch cycle only slightly changed phases of their activity in relation to the activity of motoneurons. 7. A hypothesis is advanced that generation of different kinds of limb movements is produced by one and the same central spinal mechanism which can operate in different regimes. The role of sensory input for operation of this mechanism is discussed.

Afferent Pathways↗

PubMed1993

Multiple effects of morphine on facial scratching in monkeys.

The medullary dorsal horn (MDH), the medullary homolog of the spinal dorsal horn, is a site where opioid-receptor agonists can act at opioid receptors to produce pronounced facial scratching, the behavioral correlate of pruritus. In the present study, after a 10-min baseline period, morphine (5.0 micrograms) was micro-injected into the MDH of monkeys. Behavior was videotaped and facial scratches were counted by two independent raters. Morphine greatly increased facial scratching behavior, which is consistent with previous findings where mu-opioid receptor agonists microinjected into the MDH have been to induce dose-dependent, naloxone-reversible facial scratching in monkeys. In the current research, intramuscular (IM) administration of the opioid-receptor antagonist, naloxone (0.5 mg/kg), reversed this MDH morphine-induced scratching. Additionally, IM morphine (1.0 mg/kg) produced a substantial reduction in facial scratching behavior. Scratching behavior continued at a high rate after injection of saline (0.1 mL/kg, IM). These findings support the hypothesis that morphine has both pruragenic and antipruragenic activity, depending on the site of action.

Animals↗

PubMed1997

Hindleg targeting during scratching in the locust

Intact locusts (Schistocerca gregaria) respond to tactile stimulation of their folded wings with rhythmic scratching movements of the ipsilateral hindleg that are directed towards the site of stimulation. For example, sites near the base of a wing elicit anteriorly directed scratches, whereas sites near the distal end of a wing elicit posteriorly directed scratches. Locusts also scratch in response to tactile stimulation of a wing that is held outstretched in a posture similar to that normally adopted during flight, but they fail to alter their leg targeting to compensate for this changed position of the stimulus site. Instead, they scratch at an empty point in space near the abdomen, where the stimulus site would have been if the wing was folded in the resting posture. This inappropriate scratching does not result from mechanical constraints on the hindleg's movement, from stimulation of abdominal sensory receptors, or from an absence of sensory information from the outstretched wing. It also persists when the metathoracic ganglion that controls movements of the hindlegs is isolated from the remainder of the central nervous system (CNS). Targeted scratching of sites on the wings of locusts therefore appears to be fixed relative to body coordinates and does not take into account alterations of the target wing's position.

Journal Article↗

PubMed2000

A hip joint simulator study using new and physiologically scratched femoral heads with ultra-high molecular weight polyethylene acetabular cups.

This study validates a hip joint simulator configuration as compared with other machines and clinical wear rates using smooth metal and ceramic femoral heads and ultra-high molecular weight polyethylene (UHMWPE) acetabular cups. Secondly the wear rate of UHMWPE cups is measured in the simulator with deliberately scratched cobalt-chrome heads to represent the type of mild and severe scratch damage found on retrieved heads. Finally, the scratching processes are described and the resulting scratches compared with those found in retrieved cobalt-chrome heads. For smooth cobalt-chrome and zirconia heads the wear rates were found to be statistically similar to other simulator machines and within the normal range found from clinical studies. An increased wear rate was found with cobalt-chrome heads scratched using either the diamond stylus or the bead cobalt-chrome but the greatest increase was with the diamond scratched heads which generated scratches of similar dimensions to those on retrieved heads. A greater than twofold increase in wear rate is reported for these heads when compared with smooth heads. This increased wear rate is, however, still within the limits of data from clinical wear studies.

Acetabulum↗

PubMedDate not supplied

Differential effects of insulin-like growth factors on scratch wound repair in respiratory epithelial cells.

BACKGROUND: Insulin-like growth factors (IGFs) I and II, being potent promoters of cellular growth and differentiation, were investigated for their effectiveness in improving the rate of scratch closure in human respiratory epithelium in vitro. METHODS: Human epithelial cell lines from the nasal, bronchial, and tracheal regions were analyzed for their response to IGF-I and IGF-II, in a confluent monolayer scratch assay. IGF-binding proteins (IGFBPs) produced by certain cells are able to reduce the effectiveness of the IGFs. Consequently, the analogues LongR3 IGF-I, Des1-3 IGF-I and Arg3 IGF-I were investigated also because of their lower affinity for the IGFBPs, while still retaining unaffected affinity for the IGF-I receptor. RESULTS: All growth factors that were analyzed significantly improved the rate of scratch closure in bronchial and tracheal epithelial cells (p < or = 0.05). In comparison, scratch closure was markedly slower in nasal epithelial cells and IGF-I was the most effective growth factor at effecting scratch closure in these cells. The IGF-I analogues did not significantly improve scratch closure compared with IGF-I, despite the presence of IGFBP-3 in nasal, bronchial, and tracheal epithelial cells. CONCLUSION: Addition of IGF-I to wounded nasal epithelial cells increases the rate of scratch closure and therefore may have potential for improving the healing of the nasal mucosa.

Cell Line↗

PubMed2003

Scratch-patch and patch testing in drug allergy--an assessment of specificity.

BACKGROUND: Adverse drug reactions occur frequently in daily practice, but the identification of the eliciting drugs is difficult due to a lack of standardized procedures. The aim of this study was to evaluate and compare scratch-patch and patch tests prospectively with frequently used drugs in persons exposed or not exposed to the drug in order to define a nonirritating concentration. MATERIALS AND METHODS: Altogether, 23 different drugs, mainly antibiotics and analgesics, were evaluated. Any contraindications for patch tests were excluded by a questionnaire. Sixty-one healthy individuals were tested. They were divided into two groups: Group 1 consisted of individuals who hadn't been exposed to the drug; Group 2 was comprised of individuals who had been exposed to the drug, without side effects. Each individual was tested with 10-20 scratch-patch and patch tests. The tests were performed on the upper back. Freshly prepared drug solutions were applied, on one side after scarification of the epidermis, on the other side without. Scratch-patch tests were read at 24 and 48 h, patch tests after 48 and 72 h. In addition, we included 73 individuals with a drug allergy to illustrate that the chosen drug concentrations are able to elicit a positive reaction in truly sensitized individuals. RESULTS: A positive reaction in the non-exposed and nonallergic individuals was considered to be an irritant reaction (IR). In Group 1 (non-exposed individuals), 341 scratch-patch tests were performed, with 22 showing a reaction at the first reading, 3 at the second. Of the 341 patch tests performed in this group, 21 reactions were observed at the first reading, and 7 at the second. In Group 2 (exposed individuals), 141 scratch-patch tests were performed, with 5 IR at the first reading and 1 at the second. Of the 138 patch tests performed in this group, 6 individuals showed an IR at the first, 2 at the second reading. The majority of IR were four drugs, namely cefuroxim, acetylsalicylic acid, propyphenazone/drofenin-HCl, and celecoxib. Lowering the concentration did not reduce the unspecified irritant skin reaction, while a change of the solvent (petrolatum instead of PBS) did reduce the IR. CONCLUSIONS: Our data show concentrations of 23 drugs suitable for scratch-patch or patch tests, as they do not elicit IR. Fourteen of these test preparations elicited a positive reaction in truly sensitized individuals, demonstrating that the test preparation is suitable to identify sensitized persons. Scratch-patch tests are an interesting alternative to patch tests, as they do not elicit more IR than patch tests but can be evaluated earlier. Certain drugs solved in PBS are irritant over a wide dosage range and need to be applied in petrolatum.

Adult↗

PubMed1981

[Central program for activation of hindlimb muscles during scratching in cats].

Electrical activity in nerves of different hindlimb muscles was investigated during fictitious scratching in decerebrated and decapitated cats. Phases of motor discharges could be distinguished corresponding to the phases of real scratching: aiming (flexion in the thigh and ankle joints and extension in the knee joint) and scratching (opposite movements in the same joints). According to the pattern of the discharges the hindlimb muscles were divided into three groups. In the nerves to the muscles of the 1st group the activity was observed during "initial aiming" period and during rhythmic "aiming phases". It was reciprocal to the activity in the nerves to the muscles of the 2nd group appearing during "scratching phases". In the nerves to the muscles of the 3d group the activity was observed both in "initial aiming" period and in rhythmic "aiming and scratching phases". Passive forward deflexion of the limb intensified the "scratching phases" and decreased the intensity of the discharges during "initial aiming" and "aiming phases". Physiological significance of such an organization of central program and structure of spinal scratching generator are discussed.

Animals↗

PubMed1996

Scratch resistance of rigid contact lens materials.

Practitioners have long recognised the importance of determining the extent of scratching on the surface of rigid contact lenses when deciding on lens replacement. Despite this, little research has been undertaken to define this problem. The extent of scratching of rigid contact lens materials was evaluated and this property was related to material oxygen permeability and refractive index. One hundred and forty lenses made from 28 different rigid materials were evaluated in a masked and randomised manner. Scratches were created on the front surface of the lenses using an apparatus that was specifically designed and constructed for this experiment. The extent of scratching was quantitatively evaluated using a computer-based scanning and image analysis system. The oxygen permeability of all materials was measured using the polarographic method. An Atago N3000 hand-held refractometer was used to measure the refractive index of these materials. Three significant correlations were revealed: an inverse relationship (r = -0.813, P < 0.0001) between oxygen permeability and refractive index; a positive relationship (r = 0.511, P < 0.008) between oxygen permeability and the extent of scratching; and an inverse relationship (r = -0.539, P < 0.0058) between refractive index and the extent of scratching. The information generated in this study concerning scratch resistance of rigid contact-lens materials may assist the contact lens industry and contact lens practitioners in developing and prescribing rigid lenses with optimal performance characteristics.

Contact Lenses↗

PubMed1997

[Scratching for the itch in eczema; a psychodermatologic approach].

Atopic dermatitis patients often complain of intense itching and excessive scratching. Apart from standard therapies of antihistamines with sedative side effects, there are patients who appear not to respond satisfactorily to standard medical treatments. As itching can be a skin manifestation of psychological disturbance, these patients may benefit from behaviour treatment of scratch behaviour which can have a beneficial effect on the course of atopic eczema. The scratch response is considered a classical conditioned habit and special attention was given to the function of behaviour. Two patients, a man of 27 and a girl of 11, were suffering from intractable atopic eczema. The first patient was required to record his own scratching in a diary which is part of awareness training regarding scratch situations. In the second patient impaired parent-child relationships were the main discriminative stimuli to provoke scratch behaviour. It was shown that behaviour therapy helps patients who scratch repeatedly to exercise voluntary control over it.

Adult↗

PubMed1993

Cat scratch disease in Connecticut. Epidemiology, risk factors, and evaluation of a new diagnostic test.

BACKGROUND: Although cat scratch disease is commonly diagnosed in patients who have unexplained regional lymphadenopathy after encounters with cats, its epidemiology and the risk factors for disease are not clearly defined, and there is no generally accepted diagnostic test. METHODS: We conducted a physician survey to identify cases of cat scratch disease occurring over a 13-month period in cat owners in Connecticut. We interviewed both the patients (or their parents) and controls matched for age who owned cats. Serum from the patients was tested for antibodies to Rochalimaea henselae with a new, indirect fluorescent-antibody test. RESULTS: We identified 60 patients with cat scratch disease and 56 age-matched subjects. Patients were more likely than controls to have at least one pet kitten 12 months old or younger (odds ratio, 15), to have been scratched or bitten by a kitten (odds ratio, 27), and to have had at least one kitten with fleas (odds ratio, 29). A conditional logistic-regression analysis found that in kitten-owning households, patients were more likely than controls to have been scratched or bitten by a cat or kitten (odds ratio, 12.4; 95 percent confidence interval, 1.0 to 150). Of 45 patients, 38 had serum samples with titers of 1:64 or higher for antibody to R. henselae, as compared with 4 of 112 samples from controls (P < 0.001). The positive predictive value of the serologic test was 91 percent. Of 48 serum samples from patients' cats, 39 were positive for antibodies to R. henselae, as compared with positive samples from 11 of 29 control cats (P < 0.001). CONCLUSIONS: Cat scratch disease is strongly associated with owning a kitten, and fleas may be involved in its transmission. The serologic test for rochalimaea may be useful diagnostically, and our results suggest an etiologic role for this genus.

Adolescent↗

PubMedDate not supplied

Optic neuropathy secondary to cat scratch disease: distinguishing MR imaging features from other types of optic neuropathies.

BACKGROUND AND PURPOSE: MR imaging characteristics of optic neuropathy caused by cat scratch disease have not yet been described; this lack of information may result in incorrect diagnosis and may contribute to initiation of inappropriate therapy. Our study was based on the hypothesis that cat scratch disease-related optic neuropathy has distinct MR imaging features compared with those of other types of optic neuropathies. METHODS: Eighty-two patients with various causes of optic neuropathy and available MR imaging examinations were included in this study. Two readers blinded to the diagnosis reviewed the MR images independently in regard to presence, location, and extent of optic nerve enhancement. The MR imaging findings were correlated with the final diagnosis. RESULTS: Eleven percent (9/82) of the patients received a final diagnosis of cat scratch disease. Optic nerve enhancement in patients with cat scratch disease (5/37) was localized to a 3- to 4-mm segment at the optic nerve-globe junction. All other patients with optic neuropathy (31/37) with one exception showed enhancement away from the optic nerve-globe junction or a long-segment enhancement when the optic nerve-globe junction was also involved. Four patients with cat scratch disease did not show any optic nerve MR abnormalities. CONCLUSION: Unilateral, short-segment enhancement localized to the optic nerve-globe junction is highly specific for cat scratch disease as the underlying cause of optic neuropathy and may help in establishing the diagnosis of this condition.

Adolescent↗

PubMed1991

Cat scratch encephalopathy.

Cat scratch disease is usually benign, self-limited and without sequelae. Margileth has established four clinical criteria, three of which must be satisfied to make the diagnosis: 1) a history of animal exposure, usually kitten, with primary skin or ocular lesions; 2) regional chronic adenopathy without other apparent cause; 3) a positive cat scratch disease antigen skin test; and 4) lymph node biopsy demonstrating noncaseating granulomas and germinal center hyperplasia. Central nervous system involvement in cat scratch disease has been previously reported, although it is extremely uncommon. In a several-month period, we encountered two cases of cat scratch disease complicated by encephalopathy. The intents of this paper are twofold: 1) to briefly review the current literature on cat scratch disease, 2) to demonstrate that cat scratch disease complicated by encephalopathy presents acutely with seizures, posturing and coma and resolves rapidly with supportive care.

Cat-Scratch Disease↗