Diversification of ?T Cell Responses to Carboxy-terminal Determinants within the 65-kD Heat-shock Protein Is Involved in Regulation of Autoimmune Arthritis

The T cell response to the 65-kD mycobacterial heat-shock protein (Bhsp65) has been implicated in the pathogenesis of autoimmune arthritis. Adjuvant arthritis (AA) induced in the Lewis rat (RT-1^l) by injection of Mycobacterium tuberculosis serves as an experimental model for human rheumatoid arthritis (RA). However, the immunological basis of regulation of acute AA, or of susceptibility/resistance to AA is not known. We have defined the specificity of the proliferative T cell responses to Bhsp65 during the course of AA in the Lewis rat. During the early phase of the disease (6–9 d after onset of AA), Lewis rats raised T cell responses to many determinants within Bhsp65, spread throughout the molecule. Importantly, in the late phase of the disease (8–10 wk after onset of AA), there was evidence for diversification of the T cell responses toward Bhsp65 carboxy-terminal determinants (BCTD) (namely, 417–431, 441–455, 465–479, 513–527, and 521–535). Moreover, arthritic rats in the late phase of AA also raised vigorous T cell responses to those carboxy-terminal determinants within self(rat) hsp65 (Rhsp65) that correspond in position to the above BCTD. These results suggest that the observed diversification is possibly triggered in vivo by induction of self(Rhsp65)-reactive T cells. Interestingly, another strain of rat, the Wistar Kyoto (WKY/NHsd) rat (RT-1^l), with the same major histocompatibility complex class II molecules as the Lewis rat, was found to be resistant to AA. In WKY rats, vigorous responses to the BCTD, to which the Lewis rat responded only in the late phase of AA, were observed very early, 10 d after injection of M. tuberculosis. Strikingly, pretreatment with the peptides comprising the set of BCTD, but not its amino-terminal determinants, provided significant protection to naive Lewis rats from subsequent induction of AA. Thus, T cell responses to the BCTD are involved in regulating inflammatory arthritis in the Lewis rat and in conferring resistance to AA in the WKY rat. These results have important implications in understanding the pathogenesis of RA and in devising new immunotherapeutic strategies for this disease.Rheumatoid arthritis (RA)¹ is an autoimmune disease of unknown etiology (1, 2). In the past several years, considerable interest has been generated in the role of the 65-kD mycobacterial heat-shock protein (Bhsp65) in the pathogenesis of autoimmune arthritis both in experimental animals (3, 4) as well as in humans (5–7). In RA patients, an association between T cell responses to Bhsp65 and early stages of joint inflammation has been observed (8–10), suggesting that Bhsp65-reactive T cell responses are involved in the pathogenesis of this disease. Adjuvant arthritis (AA) can be induced in the inbred Lewis rat after immunization with Mycobacterium tuberculosis in oil (11–13). The disease can also be transferred to naive Lewis rats by T cell lines reactive to peptide 180–188 of Bhsp65 (3, 14). Although arthritic Lewis rats develop vigorous T cell responses to native Bhsp65 and to peptide 180–188 of Bhsp65, neither of these is arthritogenic when injected in protein or peptide form, respectively (15, 16). Interestingly, pretreatment with Bhsp65 can protect naive Lewis rats from development of arthritis upon subsequent immunization with M. tuberculosis (4, 17), suggesting that Bhsp65 contains protective as well as disease-inducing determinants. T cell lines specific for Bhsp65 have also been shown to protect against AA (14, 18). Similarly, Lewis rats afflicted with AA are resistant to reinduction of AA (13). Neither the mechanism of natural regulation of the acute inflammatory phase of AA nor the mechanism of protection from subsequent induction of AA is known. Likewise, the immunological basis of susceptibility or resistance to AA of different rat strains has not been revealed.In the present study, we have defined the changing pattern of specificity of the T cell responses of Lewis rats to determinants within Bhsp65 during the course of AA. Arthritic Lewis rats in the early and late phase of the disease revealed distinct patterns of T cell responses to Bhsp65. Importantly, with progression of the disease, there was evidence for diversification of the T cell responses toward Bhsp65 carboxy-terminal determinants (BCTD). (The phenomenon of spreading of the T cell responses to new determinants within an antigen, after priming with a single determinant of the same antigen, has been previously described as determinant spreading [19]. On the other hand, we have termed the induction of T cell responses to new determinants after priming with the whole, multideterminant antigen as diversification [20, 21]). Moreover, arthritic Lewis rats in the late phase of AA also raised significant responses to certain carboxy-terminal determinants within self(rat) hsp65 (Rhsp65). (Rat hsp60 [22] has been referred to as rat hsp65 in this study to emphasize its relationship with Bhsp65.) These self-determinants correspond in position precisely to that of the BCTD, suggesting that diversification of response to Bhsp65 observed in vitro, might be triggered in vivo by self-hsp65. In contrast with AA-susceptible Lewis rats, MHC class II–identical, Wistar Kyoto (WKY/NHsd = WKY) rats (23, 24) were found to be resistant to induction of AA after immunization with M. tuberculosis. In fact, M. tuberculosis-immunized WKY rats raised early and vigorous responses to the BCTD to which the Lewis rats only respond during the late phase of the disease. Pertinently, pretreatment of naive Lewis rats with peptides comprising the BCTD, but not its amino-terminal determinants (BNTD), induced significant protection from AA. These results suggest that T cell responses to the BCTD are involved in regulation of acute inflammatory arthritis. Our study suggests one of the immunological bases for natural regulation of acute AA, and of protection (resistance) from development of AA.     

Pharmacogenomics: a clinician's primer on emerging technologies for improved patient care

Pharmacogenomics is a term recently coined to embody the concept of individualized and rational drug selection based on the genotype of a particular patient. Customization of drug therapy offers the potential for optimal safety and efficacy in an individual patient. Such a process contrasts current prescribing practices, which use medications shown to be safe and effective in patient populations or based on anecdotal experiences. Within patient populations, medications vary in their efficacy among individual patients. More importantly, a medication that is safe and effective in one patient may be ineffective or even harmful in another. Underlying many of these phenotypic differences are genotypic variants (polymorphisms) of key enzymes and proteins that affect the safety and efficacy of a drug in an individual patient. An understanding of these polymorphisms has the potential to enhance patient care by allowing physicians to customize the selection of medication to meet individual patient needs. Pharmacogenomics may also lead to improved compliance and shorter time to optimal disease management, thereby reducing morbidity and mortality. Significant cost savings could result from reductions in polypharmacy as well as from fewer physician encounters and hospitalizations for exacerbations of underlying illness and because of adverse drug reactions.     

The influence of high versus normal impedance ventricular leads on pacemaker generator longevity

As pacemaker generator longevity is dependent on current consumption and resistance of the pacing lead, the use of a high impedance pacing lead theoretically results in an extension of battery longevity. Therefore, the effect of high versus standard impedance ventricular leads on generator longevity was studied. In 40 patients (21 women, age 73 +/- 13 years) with a standard dual chamber pacemaker indication, a bipolar standard impedance ventricular lead was implanted in 20 patients, the remaining patients received a bipolar high impedance lead in a randomized fashion. All patients received identical pacemaker generators and atrial leads. The estimated longevity of the generator was calculated automatically by a programmed pacemaker algorithm. After a mean follow-up of 39 +/- 4.8 months, no significant differences were observed with respect to mean pacing and sensing thresholds of the atrial and ventricular leads in both groups. However, the high impedance leads displayed a significantly higher impedance and a significantly lower current drain as compared to standard impedance leads (1,044 +/- 139 vs 585 +/- 90 Omega, and 2.2 +/- 0.4 vs 4.3 +/- 1.1 mA). The extrapolated generator longevity was significantly longer in the high impedance lead group, as compared to the standard impedance lead group (107.3 +/- 8.5 vs 97.6 +/- 9.0 months; P = 0.02). In conclusion, implantation of a high impedance lead for ventricular pacing results in a clinically relevant extension of generator longevity.     

Recurrence Rates of Premalignant Lesions after CO2 Laser Vaporization

Background: Use of the CO₂-Laser (λ = 10.6 μm, continuous wave, defocussed) is an established procedure for treatment of premalignant lesions. Through employment of the sp-mode as well as scanners, thermal laser effects can be reduced but, on the other hand, a lesser degree of destruction of dysplastic cells could lead to an increased recurrence rate. The purpose of this study was to evaluate prospectively the recurrence rates resulting from different methods of CO₂ laser vaporization.Methods: From May 1995 to May, 2002, 56 patients with a total of 68 premalignant lesions of the oral mucosa were treated in a prospective clinical study. Twenty-eight lesions were vaporized with the defocussed CO₂ laser (cw, 15 W, 5–15 s, mean output 2.12 Wcm⁻²). In a further 21 lesions, a scanner (Swiftlase) was additionally employed with all other parameters held constant (mean output 212.4 Wcm⁻²). In the remaining 19 lesions, vaporization was carried out in the sp-mode (pulse duration 80 μs, pulse energy 20 mJ, mean output 228 Wcm⁻²) in which, as above, a scanner was also used. Follow-up examinations were carried out according to a standard protocol. In May, 2002, the recurrence rate in the 3 groups was determined.Results: Clinically, use of the scanner in sp-mode resulted in the most irregular tissue resection. This can be accounted for by the irregular paths of the laser beam and the pulsed delivery of the laser energy. The lowest recurrence rates were yielded by the defocussed cw-technique followed by the cw-scanner and the sp-mode.Conclusions: These results indicate that for treatment of premalignant lesions of the oral mucosa, the best results can be achieved with the defocussed CO₂ laser. The incurrence of a deep thermal effect enhances destruction of deeper-lying dysplastic cells. Apparently, other methods with lesser penetration of thermal effects (e. g. sp, scanner) do not reach the deeper-lying cells and, consequently, render higher rates of recurrence.     

Prostacyclin Reversal of Lethal Endotoxemia in Dogs

Severe endotoxemia, a condition where microembolization and intravascular coagulation are thought to play important roles, was treated experimentally with prostacyclin (PGI₂). In a study of 24 dogs, 8 control animals injected with 1.75 mg·kg⁻¹ of endotoxin died within 24 h. Six animals given intravenous aspirin 100 mg/kg, 30 min after endotoxin died. 9 of 10 dogs infused with 100 ng PGI₂·kg⁻¹·min⁻¹ for 3 h, given 30 min after the injection of endotoxin survived 24 h (P < 0.025). Injection of endotoxin resulted in a: (a) maximal 62% fall in mean arterial pressure (P < 0.001); (b) transient doubling of mean pulmonary arterial pressure (P < 0.001); (c) initial 70% drop in cardiac index (P < 0.001); (d) decline in blood platelets from 213,700 to 13,700/mm³ (P < 0.001), and leukocytes from 7,719 to < 750/mm³ (P < 0.001); (e) depressed urine output (P < 0.001); (f) 34% decrease in blood fibrinogen (P < 0.01) and an increase in fibrin degradation products > 50 μg/ml (P < 0.001); (g) fivefold increase in circulating cathepsin D titer (P < 0.005) and (h) increase in blood norepinephrine (P < 0.005), dopamine (P < 0.005), and epinephrine (P < 0.001). Aspirin treatment led to an increase in mean arterial pressure (P < 0.001) and mean pulmonary arterial pressure (P < 0.005), but cardiac index, urine flow, platelets, leukocytes, fibrin degradation products, and cathepsin D levels remained similar to untreated controls. After infusion of PGI₂ there was a: (a) prompt increase of cardiac index to base-line levels; (b) late increase in mean arterial pressure (P < 0.005) after the discontinuation of PGI₂ treatment (c) restoration of urine output; (d) increase in circulating platelets to levels still below base line but above untreated control animals (P < 0.05); (e) no effect on circulating leukocyte levels; (f) fall in fibrin degradation products to 11.2 μg/ml (P < 0.05); (g) decline in cathepsin D levels to values 60% lower than the untreated controls (P < 0.025); and (h) reduction in plasma norepinephrine levels to base line at 4 h (P < 0.005). Although the mode of PGI₂ action is not clear, it is effective in the treatment of experimental endotoxemia.     

Four weeks of daily stretch has little or no effect on wrist contracture after stroke: a randomised controlled trial

QUESTIONS: In adults undergoing rehabilitation after stroke, does 30 minutes of daily stretch of the wrist and finger flexors for four weeks prevent or reverse contracture, decrease pain, or improve upper-limb activity? Are any gains maintained one week and five weeks after the cessation of stretching? DESIGN: Randomised controlled trial with concealed randomisation, assessor blinding, and intention-to-treat analysis. PARTICIPANTS: 40 adults undergoing rehabilitation after stroke or stroke-like brain injury, who were unable to actively extend the affected wrist. INTERVENTION: Both groups received routine upper-limb retraining five days a week. In addition, the experimental group received 30 minutes daily stretch of the wrist and finger flexors five days a week for four weeks. OUTCOME MEASURES: The primary outcome was contracture, measured as torque-controlled passive wrist extension with the fingers extended. Secondary outcomes were pain at rest measured on a 10-cm visual analogue scale, and upper-limb activity measured using the Motor Assessment Scale. Outcomes were collected at baseline, post-intervention, and one and five weeks after cessation of intervention. Results: The mean effect on passive range of wrist extension was 3.8 [corrected] degrees (95% CI -2.5 to 10.1) [corrected] after 4 weeks of daily stretch, 4.1 degrees (95% CI -4.0 to 12.3) after a week of no stretch, and 3.5 degrees (95% CI -4.6 to 11.7) after a further four weeks. CONCLUSION: These data suggest that four weeks of regular stretching has little or no effect on wrist contracture after stroke. However the estimate of the size of this effect is not sufficiently precise to rule out the possibility of a marginally worthwhile effect. The stretch had no significant effect on upper-limb pain, and did not result in significantly improved upper-limb activity.     

Early apoptosis largely accounts for functional impairment of CD34+ cells in frozen-thawed stem cell grafts

Quality assessment of stem cell grafts is usually performed by flow cytometric CD34(+) enumeration or assessment of clonogenic output of fresh material. Previously, we identified the occurrence of early apoptosis, not detectable with the permeability marker 7-amino actinomycin D (7-AAD), in purified frozen-thawed CD34(+) cells, using the vital stain Syto16. Syto(high)/7-AAD(-) cells were defined as viable, Syto16(low)/7-AAD(-) cells as early apoptotic and Syto16(low)/7-AAD(+) as dead. This was confirmed in a subsequent study using frozen-thawed transplants of lymphoma patients. In the present study on grafts from multiple myeloma and lymphoma patients, we investigated the functional consequences of the early apoptotic process. The mean Syto16-defined viability was 41 and 42%, respectively, for both graft groups, compared to 78% and 72%, respectively, using 7-AAD only. The established early apoptosis marker annexin V missed roughly 50% of the early apoptosis detected with Syto16. In contrast, viability of CD34(+) cells in nonmanipulated whole blood transplants from a matched group of lymphoma patients, after 72 h of storage at 4 degrees C, was more than 90%, even with the Syto16 assay. CFU recovery (median 26-33%) after cryopreservation matched CD34(+) recovery after Syto16, but not 7-AAD correction. In contrast, colony-forming unit (CFU) recovery in the whole blood transplant was close to 100%. Furthermore, early apoptotic CD34(+) cells had lost migratory ability toward stromal cell derived factor-1alpha (SDF-1alpha). The establishment of a Syto16(high)/7-AAD(-) proportion of CD34(+) cells offers a new approach for a more correct determination of the number of viable nonapoptotic CD34(+) cells in stem cell grafts. Further development of this assay should allow its incorporation into the routine CD34(+) assessment of post-thawed samples in clinical flow cytometry laboratories.     

Estimation of Vmax in auxotonic systoles from the rate of relative increase of isovolumic pressure: (dP/dt)kP

High speed oscilloscopic recordings (4000 mm/sec) of left ventricular pressure (micromanometer) and its first derivative were used to calculate contractile element velocity (Vce) during the isovolumic period of auxotonic beats in anesthetized dogs. At 0.5-2.0 msec intervals of isovolumic systole, Vce was derived as (dP/dt)/kP, where k = 24 cm(-1). Plots of Vce and P yielded inverse curves from peak Vce to aortic valve opening pressure which averaged 27 msec in controls, and 11 msec during norepinephrine administration. Extrapolated Vmax, in muscle lengths/second, averaged 3.6 (controls), 3.6 (volume load), and 6.6 (norepinephrine). In each experimental state, Vmax was also determined from force-velocity relations of isovolumic beats (abrupt aortic occlusion) analyzed at 10 msec intervals from conventional pressure recordings. Vmax by both methods correlated well (r = 0.88). While good correlations were also noted between Vmax and maximum dP/dt, (max dP/dt)/integrated isovolumic pressure, (max dP/dt)/peak isovolumic pressure, and (max dP/dt)/kP, only the last two of these successfully distinguished changes between volume load and inotropic stimulation. Thus, assuming an unchanged series elasticity, the contractile state of the auxotonic ventricle may be determined utilizing a single high-fidelity catheter system and high speed recordings of isovolumic pressure.     

Horizontal violence among nurses in the operating room

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MANY NURSES report that sabotage is a common event in the OR, and the level of sabotage present in the OR may have an effect on overall job satisfaction among perioperative nurses.

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THIS STUDY looked at the relationship between the presence of sabotage in the OR and job satisfaction levels reported by a group of perioperative nurses in New Jersey.

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STUDY RESULTS found that although sabotage is reported as common in the OR, the presence of sabotage is not significantly associated with reported job satisfaction. AORN J 78 (December 2003) 977-988.

     

X‐linked intellectual disability update 2017

The X‐chromosome comprises only about 5% of the human genome but accounts for about 15% of the genes currently known to be associated with intellectual disability. The early progress in identifying the X‐linked intellectual disability (XLID)‐associated genes through linkage analysis and candidate gene sequencing has been accelerated with the use of high‐throughput technologies. In the 10 years since the last update, the number of genes associated with XLID has increased by 96% from 72 to 141 and duplications of all 141 XLID genes have been described, primarily through the application of high‐resolution microarrays and next generation sequencing. The progress in identifying genetic and genomic alterations associated with XLID has not been matched with insights that improve the clinician's ability to form differential diagnoses, that bring into view the possibility of curative therapies for patients, or that inform scientists of the impact of the genetic alterations on cell organization and function.