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PubMed2004

Prediction of scratch resistance of cobalt chromium alloy bearing surface, articulating against ultra-high molecular weight polyethylene, due to third-body wear particles.

The entrapment of abrasive particles within the articulation between a cobalt chromium alloy (CoCrMo) femoral component and an ultra-high molecular weight polyethylene (UHMWPE) cup of artificial hip joints or tibial inserts of artificial knee joints usually scratches the metallic bearing surface and consequently increases the surface roughness. This has been recognized as one of the main causes of excessive polyethylene wear, leading to osteolysis and loosening of the prosthetic components. The purpose of this study was to use the finite element method to investigate the resistance of the cobalt chromium alloy bearing surface to plastic deformation, as a first approximation to causing scratches, due to various entrapped debris such as bone, CoCrMo and ZrO2 (contained in radiopaque polymethyl methacrylate cement). A simple axisymmetric micro contact mechanics model was developed, where a spherical third-body wear particle was indented between the two bearing surfaces, modelled as two solid cylinders of a given diameter, under the contact pressure determined from macro-models representing either hip or knee implants. The deformation of both the wear particle and the bearing surfaces was modelled and was treated as elastic-plastic. The indented peak-to-valley height on the CoCrMo bearing surface from the finite element model was found to be in good agreement with that reported in a previous study when the third-body wear particle was assumed to be rigid. Under the physiological contact pressure experienced in both hip and knee implants, ZrO2 wear particles were found to be fully embedded within the UHMWPE bearing surface, and the maximum von Mises stresses within the CoCrMo bearing surface reached the corresponding yield strength. Consequently, the CoCrMo bearing surface was deformed plastically and the corresponding peak-to-valley height (surface roughness) was found to increase with both the hardness and the size of the wear particle. Even in the case of CoCrMo wear particles, with similar mechanical properties to those of the CoCrMo bearing surface, a significant plastic deformation of the bearing surface was also noted; this highlighted the importance of considering the deformation of the wear particles. These findings support the hypotheses made by clinical studies on the contribution of entrapped debris to increased surface roughness of CoCrMo femoral bearing surfaces.

Compressive Strength↗

PubMed2000

Inhibitory effects of methanol extracts of herbal medicines on substance P-induced itch-scratch response.

In a search for new anti-pruritic drugs we screened methanol extracts of 33 herbal medicines which have been used for cutaneous diseases for their antipruritic activity using substance P (SP) as a pruritogen in mice. When administered perorally 30 min before SP injection, methanol extracts of 6 of these herbal medicines, the root of Scrophularia ningpoensis Hemsl., the root of Patrinia villosa (Thunb.) Juss, the fruit of Forsythia suspenna Vahl, the rhizome of Cimicifuga dahurica (Turcz.) Maxim., the aerial part of Schizonepeta tenuifolia Briq. and the fruit of Cnidium monnieri (L.) Cuss, inhibited SP-induced itch-scratch response at a dose of 200 mg/kg with-out affecting locomotor activity. Dose dependence of these 6 extracts (50-500 mg/kg) was investigated and all of them inhibited SP-induced itch-scratch response, with extracts from Scrophularia ningpoensis, Schizonepeta tenuifolia and Cnidium monnieri showing particularly significant inhibition. The results suggest that these 6 methanol extracts have inhibitory activity against SP-induced itching.

Animals↗

PubMed2006

Role of substance P on histamine H(3) antagonist-induced scratching behavior in mice.

The purpose of the present study was to investigate the involvement of chemical mediators, other than histamine, in the scratching behavior induced by H(3) antagonists. Scratching behavior was induced by the histamine H(3) antagonists iodophenpropit and clobenpropit (10 nmol/site) when they were injected intradermally into the rostral part of the back of mast-cell-deficient (WBB6F1 W/W(v)) and wild-type (WBB6F1 +/+) mice. Subsequently, the effect of spantide, a tachykinin NK(1) antagonist, was measured for 60 min. The effects of the H(3) antagonists on in vitro histamine release from rat peritoneal mast cells were also investigated. When spantide was injected intradermally at a dose of 0.5 nmol/site, it significantly inhibited the response. Furthermore, iodophenpropit and clobenpropit (10(-6)-10(-8) M) did not induce histamine release in isolated rat peritoneal mast cells. Our results indicate that substance P is involved in the skin responses elicited by the histamine H(3) antagonists. Moreover, the fact that these histamine H(3) antagonists did not induce significant increases in the histamine release from rat peritoneal mast cells suggests that the histamine H(3) receptor may not be present in the peripheral cells considered in this study.

Amphetamines↗

PubMedDate not supplied

A method for predicting critical load evaluating adhesion of coatings in scratch testing.

In this paper based on the experiment principle of evaluating adhesion property by scratch testing, the peeling mechanism of thin films is discussed by applying contact theory and surface physics theory. A mathematical model predicting the critical load is proposed for calculating critical load as determined by scratch testing. The factors for correctly evaluating adhesion of coatings according to the experimental data are discussed.

Ceramics↗

PubMed1992

Capnocytophaga canimorsus septicemia associated with cat scratch.

A case is reported of Capnocytophaga canimorsus (formerly CDC group DF-2) septicemia following cat scratch in a patient with congenital asplenia. The case is of interest in that (1) the clinical presentation provided no indication as to the cause of the patient's illness. (2) C. canimorsus infection following cat bite or scratch has been reported far less frequently than following dog bite. (3) The clinical course of the illness may have been modified by previous and concurrent warfarin therapy.

Animals↗

PubMed1989

Toe scratches cause scabby hip syndrome lesions.

Scabs and scratches in the hip region of chicken carcasses have become the single most common cause of downgrading and required trimming at processing in some areas of the United States. Repeatable correlations with microbiological agents, environment, and nutrition have not been observed. The present report provides evidence that scabs and scratches, present at processing, are the result of injuries inflicted by toenails of birds as they climb on one another. Onychectomy (removal of approximately two-thirds of the distal phalanx) of all four digits of each foot prior to chick placement resulted in 3.7 and 4.8-fold reduction in subjective lesion scores and 7 to 10-fold increases in the percentage of USDA Grade A carcasses at a commercial processing plant.

Animals↗

PubMed2002

[Usefulness of ultrasonography in the study of superficial lymph nodes. A case of cat scratch disease].

Ultrasonography is a wide spread, non-invasive and repeatable imaging methodology. It is able to evidence any type of lesion and to describe its extent, its site and its content. The ultrasound role in the diagnosis of a case of cat scratch disease in a 44 year old man is described. Symptoms included intermittent fever, pain and palpable tumefactions in right armpit and elbow. The patient underwent routine and lymphoadenopathy specific laboratory data. Ultrasound examination and echo-guided fine-needle biopsy of the evident lesions were performed. These exams, related to pathological clinical presentation, have shown a chronic granulomatous lymphadenopathy like cat scratch disease. This case provides further evidence that ultrasound procedures might play an important role in differential diagnosis of palpable lesions.

Adult↗

PubMedDate not supplied

[The morphology of scratches].

On the basis of experimental and practical material it was determined that scratches were formed as a result of sliding of rough surface or sharp point along the body. In case of slight pressing narrow almost linear injuries occur in the form of chains which consist presumably of angle-shaped tears of epidermis with the bases directed to movement side. Considerable pressing results in continuous groove-shaped narrow scratches with projections of rough edges oriented to the beginning of movement.

Autopsy↗

PubMed1987

[Changes in presynaptic processes during tonic subthreshold activation of the spinal center of scratching movements in the cat].

In immobilized intercollicularly decerebrated cats tonic underthreshold activation of the spinal scratching generator (after application of tubocurarine or bicuculline on C1-C2 segments) is accompanied by an increase in primary different terminal depolarization, decrease in N1-component of cord dorsum potential evoked by stimulation of cutaneous afferents, decrease in the amplitude of DRP and early polysynaptic responses of motoneurons evoked by stimulation of cutaneous and muscle afferents; a respective rise and reduction in activity of intermediate nucleus interneurons which are mono- and di (oligo)-synaptically connected with afferent terminals. Spinalization of animal led to reverse changes. Injection of DOPA into spinal animals allowed comparing changes in the state of lumbar segmental apparatus during tonic underthreshold activation of spinal scratching and locomotor generators.

Animals↗

PubMed1986

[Relation between parameters of efferent activity and limb position during fictive scratching in the decerebrate cat].

The influence of tonic afferent inflow conditioned by ipsilateral hindlimb position on the spinal generator of scratching efferent activity parameters was investigated in immobilized decerebrated cats. When the afferent inflow was absent (after the hindlimb deafferentation) strong correlation between the motor activity parameters of successive "scratch" cycles was observed. In case of the intact afferentation this correlation was somewhat weaker and decreased with shifting the hindlimb from the aimed position to overaimed or deflecting backward. The discovered statistically significant correlations between the parameters of different motor activity phases and their dependence on the hindlimb position are organized in such a way that they can provide stability of the aimed position of the hindlimb carrying out oscillatory movements. According to the parameters of the efferent activity and their correlation type, the hindlimb deafferentation is most similar to the aimed position of the hindlimb.

Animals↗

PubMed1979

[Activity of cerebellar fastigial nucleus neurons during the fictive scratching reflex in cats].

The activity of neurons in the rostral part of the fastigial nucleus was recorded during fictious scratch reflex (FSR) in immobilized cats. During FSR the discharge frequency of many fastigial neurons was rhythmically modulated in relation to the scratch cycle: most of them fired in bursts at the end of the flexor phase or at the extensor phase of the cycle. The firing pattern of fastigial neurons was similar during both ipsilateral and contralateral FSR. Therefore the fastigial nuclei exert bilateral influences on the brain stem structures during one-sided motor activity.

Animals↗

PubMed1984

Human bubonic plague transmitted by a domestic cat scratch.

Bubonic plague was transmitted to a 10-year-old girl in Oregon by a scratch wound inflicted by a domestic cat. The cat probably was infected by contact with infected wild rodents or their fleas. Yersinia pestis was identified in Diamanus montanus fleas collected from an abandoned burrow near the patient's home. Domestic cats may infect humans with Y pestis by inoculation from a scratch.

Animals↗

PubMed1981

[Activity of propriospinal neurons of the ventral horn of the superior lumbar segments during fictive scratch reflexes].

Activity of propriospinal neurons from the ventral horn of segments L4 and L3 was recorded during fictitious scratch reflex in decerebrated cats. Neurons were identified by their antidromic response to stimulation of the ventral surface of the L7 segment. Most neurons were not active during scratching. This finding suggests that this group of neurons does not participate in the control of motoneurons during the activity of intrinsic spinal networks but rather participates in the transmission of supraspinal commands to motoneurons.

Animals↗

PubMed1994

Scratching and ultraviolet irradiation: an experimental animal model.

The purpose of the study was to establish a useful animal model for quantification of itching and to examine whether the wavelengths inducing itching were identical to those inducing erythema. Four groups of hairless mice were irradiated with 4 different light sources in order to provoke itch. The light sources were adjusted to give equal erythrogenic doses. The groups were treated 5 times weekly for a year. For the first 16 weeks the daily dose was 0.6 minimal erythema dose (MED) and for the following 36 weeks 1.2 MED. The severity of the itching in the 4 groups and in a control group of untreated mice was compared. The chosen parameters were the number of scratch-sequences and the summarized time of scratching during an observation period of 1 h. Ultraviolet irradiation provoked itching. Especially the wavelengths 315-330 nm were more itch-provoking than erythemogenic. The difference between the control group and a group treated with Philips TL12 combined with a Tempax filter was significant. An action spectrum of itching does not seem to be identical to the erythema action spectrum. The animal model described is usable to quantify itch but has to be simplified. Of the lamps used, Philips TL01 was the least itch-provoking lamp type and may be preferred in the treatment of itching diseases.

Animals↗

PubMed1983

Cat-scratch disease associated with an osteolytic lesion.

Lytic bone involvement accompanying cat-scratch disease has been described previously in three patients. I observed a fourth patient with this pathologic condition and noted variations among the four patients. To my knowledge, this patient is the first in whom extension from an involved lymph node to a bone was direct.

Bone Resorption↗

PubMedDate not supplied

Gray-scale sonographic evaluation of cervical lymphadenopathy in cat-scratch disease.

PURPOSE: The aim of this study was to characterize the gray-scale sonographic findings in the lymph nodes of patients with cat-scratch disease (CSD). METHODS: We analyzed the sonograms of cervical lymph nodes in 41 patients with proven CSD between January 1997 and October 1999. RESULTS: A total of 222 involved lymph nodes were detected. Involved nodes were most commonly found in the middle cervical (58%), parotid (37%), upper cervical (37%), and submandibular (17%) regions. We found acute, chronic, or abscessed lymphadenopathy in 63%, 12%, and 24% of patients, respectively. The size of involved lymph nodes ranged from 12 x 4 mm to 35 x 26 mm. The largest involved node had a short axis/long axis ratio of 0.5 or more in 61% of patients. Useful features for the differential diagnosis included markedly decreased echogenicity (100%), normal surrounding tissues (100%), and the presence of an echogenic hilum (76%). Posterior sound enhancement was significantly associated with larger and abscessed lymph nodes. CONCLUSIONS: Despite the absence of a specific sonographic finding for CSD, gray-scale sonography can provide clues to the diagnosis of CSD in the proper clinical setting.

Adolescent↗

PubMed2005

Cat-scratch disease-associated arthropathy.

OBJECTIVE: To characterize the articular manifestations of cat-scratch disease (CSD) and to evaluate the long-term clinical outcome of those manifestations. METHODS: A community- and hospital-based surveillance study of CSD was conducted in Israel between 1991 and 2002. CSD was defined as present in a patient when a compatible clinical syndrome and a positive confirmatory finding of Bartonella henselae (by serology and/or polymerase chain reaction) were identified. CSD patients with arthropathy (arthritis/arthralgia) that limited or precluded usual activities of daily living constituted the study group. Patients were followed up until > or =6 weeks after resolution of symptoms, or if symptoms persisted, for >/=12 months. CSD patients without arthropathy served as controls. RESULTS: Among 841 CSD patients, 24 (2.9%) had rheumatoid factor-negative arthropathy that was often severe and disabling. Both univariate and multivariate analyses identified female sex (67% of arthropathy patients versus 40% of controls; relative risk [RR] 2.5, P = 0.047), age older than 20 years (100% of arthropathy patients versus 43% of controls; RR 4.9, P = 0.001), and erythema nodosum (21% of arthropathy patients versus 2% of controls; RR 7.9, P = 0.001) as variables significantly associated with arthropathy. Knee, wrist, ankle, and elbow joints were most frequently affected. Ten patients (42%) had severe arthropathy in the weight-bearing joints, which substantially limited their ability to walk, and 4 of these patients were hospitalized. All of the patients had regional lymphadenopathy, 37.5% had nocturnal joint pain, and 25% had morning stiffness. Nineteen patients (79.2%) recovered after a median duration of 6 weeks (range 1-24 weeks), whereas 5 patients (20.8%) developed chronic disease persisting 16-53 months (median 30 months) after the onset of arthropathy. CONCLUSION: This is the first comprehensive study of arthropathy in CSD. CSD-associated arthropathy is an uncommon syndrome affecting mostly young and middle-age women. It is often severe and disabling, and may take a chronic course.

Adolescent↗

PubMed1995

Cytologic diagnosis of cat scratch disease (CSD) by fine-needle aspiration.

Cat scratch disease (CSD) is usually a benign, self-limited lymphadenitis, characterized by suppurative granulomas. It can, however, produce a wide spectrum of clinical symptoms and cytologic changes and be the source of diagnostic dilemmas. Identification of pleomorphic bacilli (PB) with silver impregnation stains aids in the diagnosis, but this has not been well documented in cytologic preparations or in cases without the classic morphologic changes. We reviewed 13 aspirations from eight patients (aged 13-36 yr) occurring over a 15 mo time period, all clinically or cytologically suspicious for CSD. Sites included: axilla (6), parotid (3), epitrochlear (1), neck (1), submental (1), and intraclavicular (1) nodes. Neoplasia was initially suspected clinically in 38% of the cases. All but two patients had cat exposure on subsequent interview. The cytologic differential included bacterial abscess and lymphoproliferative disorders in 31%. Neither granulomas nor suppurative inflammation were seen in all cases. Changes included: granulomas (77%), PMNs (62%), dispersed epithelioid histiocytes (46%), and suppurative granulomas (38%). A modified silver stain (Modified Steiner, Sigma Diagnostics, St. Louis, MO) was performed on all specimens. Silver positive organisms were seen in 69% of cases and were not limited to those preparations with suppurative granulomas. Fine-needle aspiration biopsy (FNAB) is an effective method for diagnosing CSD despite its heterogeneous appearance; and, when combined with clinical information and silver staining, may obviate the need for excision.

Adolescent↗