High frequency electrical stimulation attenuates progressive necrosis and cavitation following spinal cord injury

This study evaluates the influence of preconditioning by following electrical stimulation on primary and secondary lesion formation following spinal cord injury in rats. The dorsal surface of the spinal cord was stimulated (500 Hz. 10 pulses/train, inter train interval of 10 sec. for 2 hrs) at the T7 level 24 hrs before a right side hemisection, carried out immediately after injury and maintained every 24 hrs for 7 days. Preconditioning by electrical stimulation of the spinal cord activates reactive astrocytes and significantly attenuates edema and progressive necrosis and cavitation, concerning especially the primary (1, 3 weeks post injury) and secondary (24 hrs, 1, 3 weeks post injury) lesion volume. The results suggest that pre-conditioning by electrical stimulation prevents spinal cord secondary lesion formation after injury, and that the beneficial effect is provided by astroglial cells with regard to their ability to attenuate trauma induced cellular cascades.

Motor evoked potentials following transcranial magnetic stimulation after middle cerebral artery and/or basilar artery occlusions in rats

To clarify the significance of motor evoked potentials following transcranial magnetic stimulation (MMEPs) in acute stage of cerebral ischemia, MMEPs were recorded in rats with the right middle cerebral artery (MCA) and/or the basilar (BA) artery occlusions. MMEPs from bilateral forelimb muscle and regional cerebral blood flow (rCBF) of the pons were recorded simultaneously. After MCA occlusion, the amplitudes of MMEPs from left forelimb were increased up to approximately 184-221% of the pre-ischemic value for 60 min, though the latencies were unchanged. On the other hand, in the rats of BA occlusion and both BA and MCA occlusion groups, MMEPs amplitudes were decreased to 8-25% of the pre-ischemic value for 60 min. Pontine rCBF was decreased to 28-44% in both groups. As a mechanism of the facilitation of MMEPs after MCA occlusion, the affection of the inhibitory mechanism between the cerebral cortex and the generator of MMEPs by MCA occlusion is speculated.

Anxiety induced by repetitive transcranial magnetic stimulation is suppressed by chronic treatment of paroxetine in rats

Repetitive transcranial magnetic stimulation (rTMS) has been shown to have a therapeutic effect on affective disorder and anxiety disorders. However, some reports have linked rTMS to a significant increase in anxiety in normal volunteers. This study investigates the effect of rTMS on anxiety and the use of acute and chronic paroxetine treatment on this animal model of anxiety. In normal rats, rTMS for 10 days induced anxiety, as shown by elevated plus maze, black and white box, and conditioned fear tests. This anxiety was suppressed by chronic, but not acute, paroxetine. These results suggest that rats receiving chronic rTMS treatment can be used as a model of anxiety and that the anxiety induced by rTMS might involve the serotonergic system.

Serum level of cartilage oligomeric matrix protein (COMP) in equine osteoarthritis

This study was designed to assay and compare cartilage oligomeric matrix protein (COMP) in horse sera, in samples from normal and joint diseased horses, and to investigate the relationships between COMP in sera and synovial fluids (SF) with keratan sulphate (KS) data. Sera from 38 horses free of any joint pathology (controls) and from horses with aseptic joint disease (AJD horses, n = 40) were assayed for COMP and KS concentrations. Of the 78 horses in the study, 53 were also assayed for COMP and KS concentrations in SF. COMP and KS were measured by inhibition ELISA, using monoclonal antibodies 12C4 and 5D4, respectively. The COMP concentration in sera from AJD horses (mean +/- s.d. 10.7 +/- 7.4 microg/ml) was significantly (P<0.02) lower than in control sera (14.8 +/- 7.8 microg/ml). The joint disease sera also had significantly lower (P<0.01) KS levels (180.5 +/- 61.8 ng/ml) than controls (237.1 +/- 116.1 ng/ml). A significant correlation (r = 0.52, n = 53, P<0.001) was seen between serum and SF in COMP levels; no such relationship was seen in KS levels. It is possible that serum COMP concentration could be a more specific marker of equine joint disease than any other described to date.

Effects of inducible nitric oxide synthase and xanthine oxidase inhibitors on SEB-induced interstitial pneumonia in mice

The authors have previously reported that intratracheal instillation of staphylococcal enterotoxin-B (SEB) induced interstitial pneumonia (IP) in autoimmune-prone mice. SEB-reactive T-cells were critically involved in the development of IP in this model. Concern has arisen about the hazards of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the process of lung injury and fibrosis. Therefore, the involvement of nitric oxide (NO) and superoxide anion (O2-) in the pathogenesis of IP in this autoimmune-prone model has been investigated. Nitrite/nitrate levels were increased in bronchoalveolar lavage (BAL) fluid and serum from SEB-injected mice. The signal of the NO-(N-(dithiocarboxy) sarcosine)2-Fe2+ complex was detected in the SEB-injected lung and whole blood by electron paramagnetic resonance (EPR) spectroscopy. NO production was significantly decreased by aminoguanidine (AG) treatment. Xanthine oxidase (XO) activity in the lung, BAL fluid, and plasma was increased with instillation of SEB, and 4-amino-6-hydroxypyrazolo(3,4-d)-pyrimidine (AHPP) significantly inhibited XO activity. Moreover, both AG and AHPP significantly decreased production of pro-inflammatory cytokines, numbers of infiltrated cells in BAL fluid, and the area of thickened alveolar septa in the SEB-injected lung. In conclusion, the overproduction of nitric oxide and super oxide anion were implicated in the pathogenesis of interstitial pneumonia, and inducible nitric oxide synthase and xanthine oxidase inhibitors had protective effects against interstitial pneumonia in this model.

Interplay of the main chain, chiral side chains, and solvent in conformational transitions: poly([(R)-3,7-dimethyloctyl]-[(S)-3-methylpentyl]silylene)

Light scattering, sedimentation equilibrium, viscosity, circular dichroism (CD), and UV absorption (UV) measurements were made on dilute solutions of poly([(R)-3,7-dimethyloctyl]-[(S)-3-methylpentyl]silylene)(PRS) as functions of molecular weight. From light scattering and viscosity data, PRS is found to be a very stiff polymer of persistence length q as large as 103 nm at 25 degrees C, essentially a 7(3) helix found in the solid state; q increases only gradually with lowering temperature between -15 and 25 degrees C. The CD data show that PRS undergoes a conformational transition around 3 degrees C in isooctane (transition temperature T(c)). The CD signal is largely positive at low temperatures, passes through zero at T(c), and becomes largely negative at higher temperatures; T(c) is independent of sample's chain length N. This is a highly cooperative helix (M)-to-helix (P) transition depending remarkably on N, as PRS is substantially rodlike. The CD data are converted to the fraction f(P) of P helix as a function of N and analyzed successfully by a statistical mechanical theory based on a helix reversal model, where a polymer chain consists of M and P helices intervened by helix reversals, with the result that the free energy difference DeltaG(h) between P and M shows a temperature dependence similar to that of 2f(P) - 1, whereas the helix reversal energy is substantially constant at 1.2 x 10(4) J mol(-1); the latter value means that the helix reversal occurs only once in 100 Si units or less. This DeltaG(h) change and solvent dependence of T(c) are explained by a double-well potential for the rotation about Si-Si bonds, which incorporates into DeltaG(h) the solvent interactions with the helical grooves of side chains surrounding the main chain. Detailed features of UV absorption spectra at different temperature and molecular weights are also presented.

Nearly pure blue photoluminescent poly{2,7-[9-{3,5-bis[3,5-bis(benzyloxy)benzyloxy]benzyl}-9 -(3,6-dioxaoctyl)]fluorene} in filmElectronic supplementary information (ESI) available: characterization data for 2, 3, and 4, and measurement details of the quantum yield in THF solution. See http://www.rsc.org/suppdata/cc/b1/b108097k/

The first unsymmetrically substituted polyfluorene bearing a bulky poly(benzyl ether) dendron and less bulky 3,6-dioxaoctyl groups in the 9-position was designed and synthesized, which gives almost a pure bluish photoluminescence with negligible weak greenish excimer emission around 520 nm even in a thermally annealed thin solid film.

Computing handedness: quantized and superposed switch and dynamic memory of helical polysilylene

Two new conjugating helical polymers comprising a rodlike silicon backbone and enantiopure chiral pendants, poly[(R)-3,7-dimethyloctyl-(S)-3-methylpentylsilylene] (PS-1) and its diastereomeric poly[(S)-3,7-dimethyloctyl-(S)-3-methylpentylsilylene] (PS-2), were prepared. Molecular mechanics calculations of PS-1 and PS-2 model oligomers indicated a double well potential energy curve corresponding to almost enantiomeric helices with dihedral angles of 150-160 degrees (P-motif, global minimum) and 200-210 degrees (M-motif), regardless of their tacticity. Experimentally, it was found that PS-1 in dilute isooctane revealed switchable ambidextrous helicity on application of a thermal energy bias. Although PS-1 featured three distinct switching regions, viz. "region 1, between -80 and -10 degrees C", "region 2, between -10 and +10 degrees C", and "region 3, between +10 degrees C and +80 degrees C", the switching properties were interpreted as the result of superposed P- and M-helicities, undergoing dynamic pseudo-racemization or oscillation. Oscillating helicity in region 2 was roughly estimated to be about 13 cm(-)(1). The superposed helicity in region 2 was critical since it afforded molecular recognition ability with a dynamic memory function that was highly susceptible to solvent molecular topology and volume fraction. This could lead to potential as a molecular information processor to serve as a gauge of chemical properties. On the other hand, PS-2 could not switch its preferential screw-sense in the range of -80 to +80 degrees C. This may be related to greater differences the potential energy curve between P- and M-motifs.

Retro-odontoid soft tissue mass associated with atlantoaxial subluxation in an elderly patient: a case report

BACKGROUND

We present the case of an elderly patient with a retro-odontoid soft tissue mass associated with atlanto-axial subluxation.

CASE DESCRIPTION

A 74-year-old man was admitted to our hospital with progressive motor weakness in his right arm and neck pain. Radiological examinations revealed atlantoaxial subluxation and diffuse degenerative changes. Cervical MRI revealed a syrinx at the C1 level and a retro-odontoid soft tissue mass that severely compressed the spinal cord. The mass was of low signal intensity on both T1- and T2-weighted images. Conservative therapy could not stop the progression of his symptoms, so posterior decompression via a laminectomy of C1 and occipitocervical fixation was performed. These procedures resulted in an improvement of his neurological condition and in reduction of the mass and the compression of the spinal cord.

CONCLUSION

The patient lacked any specific conditions that might have caused chronic atlantoaxial subluxation. The degenerative changes alone might have provoked chronic atlantoaxial subluxation and a subsequent retro-odontoid soft tissue mass. In patients with this condition, posterior fixation without direct removal of the mass should be the first choice for surgical intervention.

Solvent and temperature effects on the chiral aggregation of poly(alkylarylsilane)s bearing remote chiral groups

Novel switchable chiroptical characteristics of poly(alkylarylsilane) microaggregates, controllable by the choice of good/poor solvent ratio (solvent polarity), solvent addition order, and sample temperature are described. The formation of stable chiral aggregates depends critically on the polysilane structure and stereochemistry. Poly[n-hexyl-(p-(S)-2-methylbutoxyphenyl)silane] (1), optically inactive in molecularly dispersed THF solution due to the existence of dynamically equivalent amounts of right (P)- and left (M)-handed screw sense helical main chain domains, shows a marked bisignate CD signal due to the formation of chiral aggregates in good/poor cosolvent systems. The sign and magnitude of the CD signals are dependent on solvent polarity, solvent addition order, and thermal effects. The less sterically hindered poly[methyl-(p-(S)-2-methylbutoxyphenyl)silane] (2) exhibits a weak, bisignate, nonswitchable CD signal in only the toluene/acetonitrile system, and no CD signals are evident in pure toluene or THF due to masking of the helicity. In contrast, although the even less sterically hindered, less polar poly[methyl-(m-(S)-2-methylbutoxyphenyl)silane] (3) does show optical activity in pure THF or toluene (negative CD signal at 310 nm), the CD signal disappears on formation of aggregates in good/poor cosolvent systems.

Evaluation of collagenase-induced mitral valve regurgitation in dogs

OBJECTIVE

To investigate the hemodynamic changes induced by injecting collagenase into the mitral valve to induce mitral valve regurgitation (MVR) in dogs.

ANIMALS

9 healthy Beagles.

PROCEDURE

Dogs were randomly assigned to 3 groups: control (saline [0.9% NaCl] solution; n = 3), single collagenase injection (C1; 3), and 2 collagenase injections (C2; 3). Open-heart surgery was performed, and saline or collagenase solutions were injected into the mitral valve. Before and weekly for 11 weeks after surgery, radiography, echocardiography, and phonocardiography were performed. Mean pulmonary arterial pressure and mean pulmonary arterial wedge pressure (mPAWP) were measured before and 11 weeks after surgery. Postmortem examinations were performed after dogs were euthanatized.

RESULTS

No changes were detected in the control group during the 11-week follow-up period. A systolic murmur and MVR developed 1 week after surgery in groups C1 and C2. The murmur changed from a protosystolic to a pansystolic murmur, and left atrial diameter and the left atrial-to-aortic root diameter ratio increased with time. Mean pulmonary arterial pressure and mPAWP were greater 11 weeks after surgery in groups C1 and C2, compared with presurgery values. During necropsy, tissue loss was detected in the mitral valve at the site of collagenase injection. Degree of regurgitation corresponded to lesion size.

CONCLUSIONS AND CLINICAL RELEVANCE

Injection of collagenase into the mitral valve of healthy dogs induced MVR, and dogs with MVR developed progressive hemodynamic changes without acute overload. Collagenase-induced MVR may be an appropriate model for evaluation of prognostic markers of idiopathic MVR in dogs.

Uterine horn torsion in two non-gravid bitches

Uterine torsion secondary to sacculation of the uterine horns was diagnosed in two non-gravid bitches which were presented with anorexia, polydipsia and an acutely swollen abdomen. On the basis of the radiological and ultrasonographic findings, which indicated the presence of an enlarged spherical or tubular structure filled with hypoechoic material in the caudal abdomen, a tentative diagnosis of pyometra was made. Exploratory laparotomy revealed unilateral uterine horn torsion along the longitudinal axis, with bilateral fluid-filled sacculations. Ovariohysterectomy was performed in both cases. Pathological examination of the uteri demonstrated haematometra in one dog and pyometra in the other.

Arabinogalactan protein and wall-associated kinase in a plasmalemmal reticulum with specialized vertices

Arabinogalactan protein and wall-associated kinase (WAK) are suspected to be regulatory players at the interface between cytoplasm and cell wall. Both WAK(s) and arabinogalactan shown likely to represent arabinogalactan protein(s) have been visualized there with computational optical-sectioning microscopy. The arabinogalactan occurs in a polyhedral array at the external face of the cell membrane. WAK, and other proteins as yet unidentified, appear to fasten the membrane to the wall at vertices of the array. Evidence is presented that the array bears an important part of the mechanical stress experienced by the membrane, and it is speculated that the architectural organization of arabinogalactan protein, WAK, and other components of the array is critical for coordination of endomembrane activities, growth, and differentiation. The array has been named the plasmalemmal reticulum.

Bacterial superantigen staphylococcal enterotoxin B induces interstitial pneumonia in SCID mice reconstituted with peripheral blood mononuclear cells from collagen vascular disease patients

To investigate whether superantigens induce interstitial pneumonia associated with collagen vascular disease (CVD), staphylococcal enterotoxin B (SEB) was intratracheally administered to SCID mice reconstituted with peripheral blood mononuclear cells (PBMCs) from CVD patients that suffered lung complications. Although a slight accumulation of inflammatory cells into the perivascular area was seen in the lungs of SCID mice injected with PBMCs from CVD patients or healthy donors, SEB administration significantly increased the severity of inflammation in the lungs of SCID mice that received CVD patient PBMCs. Furthermore, human leukocytes were detected by immunohistochemistry in the lungs of SCID mice that received SEB after reconstitution with PBMCs from CVD patients but not in other groups of SCID mice. CD45RO(+) memory T cells comprised the majority of infiltrating human leukocytes. These results suggest the possibility that external superantigens may induce the development of interstitial pneumonia in patients that have a genetic background predisposition to autoimmune disease.

Near-UV, circular dichroism, and fluorescence spectra of a rigid rodlike helical polysilane bearing trietheral moiety in ethanol/water

An optically active, rigid rodlike helical polysilane with 6, 9, 12-trioxatetradecyl and (S)-2-methylbutyl substituents (1) was newly obtained as a very high molecular weight polymer of several million. Due to the presence of trietheral substituent, 1 was readily soluble in a polar solvent such as ethanol and a mixture of ethanol and water, but was insoluble in pure water. Polysilane 1 in pure ethanol at room temperature exhibited an intense and narrow ultraviolet (UV) and circular dichroism (CD) absorptions at 323 nm, associated with an almost mirror imaged fluorescence (FL) at 328 nm, that are characteristics of rigid rodlike, single-screw-sense helical polysilanes reported previously. When solution temperature was changed from 60 degrees C to -104 degrees C, a global shape of 1 expanded associated with an increase of segment length, whereas a screw pitch tended to be wound tightly. On the other hand, as a solvent polarity became poor, a global shape of 1 shrunk associated with an decrease of segment length and formed a chiral motif with an M-helicity between two helical segments with a kink. At a ratio of 50% of ethanol/water of 50:50 (v/v), 1 became insoluble and formed aggregates.

The risk of contrast media-induced ventricular fibrillation is low in canine coronary arteriography with ioxilan

Previous studies have proposed that sodium supplement to nonionic contrast media (CM) can decrease the risk of ventricular fibrillation (VF). This study was designed to compare the occurence of VF induced by ioxilan (containing 9 mmol/LNa+) with other nonionic CMs. After wedging a catheter in the right coronary artery, test solutions including ioxilan, ioversol, iomeprol, and iopromide were infused for 30 sec at the rate of 0.4 ml/sec or until VF occurred. Then, incidence of VF, contact time (i.e. the time required to produce VF), and QTc were measured. Also, the CMs other than ioxilan were investigated at sodium levels adjusted to 9 and 20 mmol/L Na+. The incidence of VF with ioxilan (0%) was the lowest of all. In the other CMs, the incidence decreased in accordance with increase of sodium. Iomeprol and iopromide showed significant reduction of VF incidence at the sodium level of 20 mmol/L. The higher sodium supplements also prolonged the contact times. The increase of QTc was the greatest in ioxilan. Ioxilan has the least arrythmogenic property among the current low-osmolality nonionic CMs. This property might be attributable to an optimal sodium concentration of 9 mmol/L in the CM.

Role of T cells in bronchoalveolar space in the development of interstitial pneumonia induced by superantigen in autoimmune-prone mice

To study the mechanisms underlying the development of interstitial pneumonia in autoimmune disease, we analyzed bronchoalveolar lavage fluid (BALF) in an animal model of interstitial pneumonia in which an intratracheal instillation of staphylococcal enterotoxin B (SEB) induced interstitial pneumonia in autoimmune-prone mice. Increases in the numbers of total cells, macrophages, lymphocytes, and neutrophils were observed in BALF from SEB-treated MRL +/+ mice, and peaked at 3 d after SEB administration (Day 3). Flow cytometric analyses revealed increases in SEB-reactive Vbeta8(+) T cells, indicating that SEB-reactive cells play an important role in bronchoalveolar space. The expressions of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, JE/monocyte chemoattractant protein-1, regulated on activation, normal T cells expressed and secreted, and KC/gro messenger RNA (mRNA) in BALF cells from SEB-treated mice peaked at Day 3. Increased expression of TNF-alpha mRNA was observed mainly in macrophages and CD8(+) T cells, and the increase in IFN-gamma mRNA was observed mainly in CD8(+) T cells in BALF at Day 3. The expression of platelet-derived growth factor mRNA was very weak at Day 3 but strongly expressed at Day 14. An immunosuppressant, FK506, but not corticosteroid, suppressed SEB-induced T-cell expansion in BALF as well as increased cytokine and chemokine production in the bronchoalveolar space of SEB-treated mice. Histologically, FK506 but not corticosteroid significantly reduced both the cell infiltration to alveolar septal walls and the synthesis of pulmonary collagen fibers. Further, transfer of T cells of MRL +/+ mice with SEB into SCID mice gave rise to interstitial pneumonia. These results suggest that superantigen-reactive T cells in the bronchoalveolar space may trigger the development of interstitial pneumonia in this model.

Cloning of feline cDNA encoding the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4)

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a CD28 homologue which down-modulate T cell responses rather than augment them. To investigate its biological role in feline immune system, we cloned and sequenced full-length feline CTLA-4 (fCTLA-4) cDNA by RT-PCR from pokeweed mitogen stimulated peripheral blood lymphocytes. The fCTLA-4 contains an open reading frame of 669 nucleotides, coding for a polypeptide of 223 amino acids. The predicted fCTLA-4 amino acids sequence shows the homology of 86.6%, 87.0%, and 76.2% with human, bovine, and murine molecules respectively. The hexapeptide motif (MYPPPY) within the extra-cellular domain of CTLA-4 molecule, which is believed to be responsible for interaction with the B7 family members, is completely conserved in all the species.

Salt water promotes hypertension in Dahl-S rats

Hypertension was induced in Dahl-salt-sensitive (Dahl-S) rats by administering salt in drinking water. Control rats receiving tap water did not show a significant change in blood pressure or abnormalities in the kidney. Rats receiving 0.5% NaCl solution developed moderate hypertension and renal lesions. Rats receiving 1.0% NaCl solution showed prominent and increasing hypertension and severe renal damage. This method of salt administration should be simpler than administration in the diet as a means of promoting renal hypertension. The lower concentration salt water caused chronic mild hypertension in Dahl-S rats, and may serve as a useful model for progressive hypertension.

Genetic approaches to neurotrauma research: opportunities and potential pitfalls of murine models

Genetic strategies provide new ways to define the molecular cascades that regulate the responses of the mammalian nervous system to injury. Genetic interventions also provide opportunities to manipulate and control key molecular steps in these cascades, so as to modify the outcome of CNS injury. Most current genetic strategies involve the use of mice, an animal that has not heretofore been used extensively for neurotrauma research. Therefore, one purpose of the present review is to consider how mice respond to neural trauma, focusing especially on recent information that reveals important differences between mice and rats, and between different inbred strains of mice. The second aim of this review is to provide a brief introduction to the opportunities, caveats, and potential pitfalls of studies that use genetically modified animals for neurotrauma research.

Circulatory arrest under hypothermic anesthesia using abdominal cavity cooling

The purpose of this study was to investigate the potential for circulatory arrest during surgery under systemic hypothermic anesthesia, using the abdominal cavity cooling method. Eighteen beagles, each weighing 10.5 +/- 2.3 kg, were cooled by filling the abdominal cavity with crushed ice. Just after the esophageal temperature reached 30 degrees C, the heart was exposed, and a left-heart bypass from the left atrium to the aortic root was created. At 20-23 degrees C, the heart was arrested by infusing cooled Young's solution into the aortic root. After a period of cardiac arrest, resuscitation and rewarming were initiated simultaneously. Throughout these procedures, an electrocardiogram (ECG) and the arterial blood pressure (ABP) were monitored continuously. Hematocrit (Ht), total protein (TP), and arterial blood pH and gases were measured every 30 min. The recoveries after surgery were divided into three types as follows, 1) recovery without any complications-11 dogs, 2) not extubated with spontaneous breathing-4 dogs, 3) no reappearance of heart beat-3 dogs. PaO2 during resuscitation was significantly higher in dogs which recovered completely than in the rest of the dogs. These results suggest that hypothermia induced by the abdominal cavity cooling method could be useful for organ-protection during open-heart surgery, and that successful recovery may be attained through protection of the lung as well as the myocardium.

Participation in cooperative learning activities by children with specific language impairment

This study examined the involvement of children with specific language impairment (SLI) in a cooperative group task. Subjects consisted of 6 target children with SLI (ages 8;10 to 12;5), 6 target children matched for chronological age (CA), and 6 target children with similar language skills (LS). Each target subject interacted with 2 peers of the same age and gender. This resulted in 54 subjects participating in 18 triadic interactions (each involving 1 target subject and 2 partners). Each triad of children worked together to build a cardboard periscope. Verbal and nonverbal collaborative activity were analyzed during the interactions. All members of the CA and LS triads were highly collaborative and worked and talked together while assembling the periscope. Four of the children with SLI played very minor roles in the cooperative work within their triads. Their verbal contributions were limited, and their nonverbal activity was minimal. When children with SLI did collaborate in building the periscope, they performed less specialized tasks than did their partners.

Negotiation skills of children with specific language impairment

This study examined the ability of 6 children with specific language impairment (SLI), ages 8; 10 to 12;5 (yr; mon) to participate in a negotiation sequence with 2 same-age peers in triadic interactions. Negotiation sequences were analyzed using a system based on Selman's interpersonal negotiation strategies (INS) model (Selman, 1981). The negotiation skills of children with SLI were compared to those of 6 children matched for chronological age (CA) and 6 children of similar language (LS) abilities, participating in the same task. Children with SLI did not produce significantly fewer utterances than the partners with whom they interacted. However, they did produce a significantly smaller percentage of the negotiation strategies produced by their triads. They also used developmentally lower level strategies than either of the partners in their triads. Children interacting within the CA and LS triads did not produce similar differences.