Heat shock protein 70 kDa chaperone/DnaJ cochaperone complex employs an unusual dynamic interface

The heat shock protein 70 kDa (Hsp70)/DnaJ/nucleotide exchange factor system assists in intracellular protein (re)folding. Using solution NMR, we obtained a three-dimensional structure for a 75-kDa Hsp70–DnaJ complex in the ADP state, loaded with substrate peptide. We establish that the J domain (residues 1–70) binds with its positively charged helix II to a negatively charged loop in the Hsp70 nucleotide-binding domain. The complex shows an unusual “tethered” binding mode which is stoichiometric and saturable, but which has a dynamic interface. The complex represents part of a triple complex of Hsp70 and DnaJ both bound to substrate protein. Mutagenesis data indicate that the interface is also of relevance for the interaction of Hsp70 and DnaJ in the ATP state. The solution complex is completely different from a crystal structure of a disulfide-linked complex of homologous proteins [Jiang, et al. (2007) Mol Cell 28:422–433].     

Crossing the divide: transition care services for young people with HIV-their views

Following the introduction of highly active antiretroviral therapy, an expanding cohort of adolescents with perinatally acquired HIV (PaHIV) is surviving and emerging from pediatric services with complex transition health care requirements. Transfer from pediatric to adult services has been associated with poorer health outcomes in other chronic diseases. Young people with HIV have the additional burden of stigma, secrecy, and the risk of transmitting HIV to partners and offspring. Maintaining engagement in health care during adolescence is critical. We compare reported satisfaction surveys of health care experiences and preferences of young people with PaHIV attending a U.K. transition outpatient service with young people attending a young persons' diabetes transition service in Australia. All 21 patients in the United Kingdom and 39 young people approached in Australia agreed to participate. The median age for both groups was 19 years, 67% of the PaHIV group were black African and 74% of diabetic group white Australian. Ninety-five percent (18/19) of those with PaHIV and 87% (34/39) with diabetes felt their transition was an easy process. Sixty-eight percent (13/19) of young people with PaHIV and 72% (28/39) of diabetic patients felt moving to their current service had a positive effect on their health. Being treated as an individual, comprehensive management explanations and encouragement to develop independence were cited as "strongly important" by over three quarters of participants with PaHIV. This service evaluation illustrates that careful transition can be a positive event for young people with PaHIV, comparable to that of a well-established diabetes services.     

A phase 2 study of the safety and efficacy of rituximab with plasma exchange in acute acquired thrombotic thrombocytopenic purpura

The safety and efficacy of weekly rituximab 375 mg/m(2) (×4), given within 3 days of acute TTP admission, with standard therapy (PEX and steroids) was evaluated. Clinical outcomes were compared to historical controls (n = 40) who had not received rituximab. Within the trial group, 15 of 40 required ICU admission and 15% of all cases with the highest troponin T levels on admission were ventilated. Before the second rituximab infusion, 68% of cases had a platelet count > 50 × 10(9)/L and 38% > 150 × 10(9)/L. Fewer PEX were required in whites compared to nonwhite in the rituximab group (mean 14 vs 21, P = .0095). Inpatient stay was reduced by 7 days in the non-ICU trial cases compared to historical controls (P = .04), especially in whites, with a mean reduction of 7 days (P = .05). Ten percent of trial cases relapsed, median, 27 months (17-31 months), compared to 57% in historical controls, median 18 months (3-60 months; P = .0011). There were no excess infections or serious adverse events with rituximab. In conclusion, rituximab appears a safe and effective therapy. Inpatient stay and relapse are significantly reduced in the rituximab cohort. Rituximab should be considered in conjunction with standard therapy on acute presentation of TTP. This study was registered at www.clinicaltrials.gov as NCT009-3713.     

Should oxyhaemoglobin saturation be monitored continuously during the 6-minute walk test?

Guidelines for conducting the 6-minute walk test (6MWT) indicate that oxyhaemoglobin saturation (SpO( 2)) should not be monitored constantly during the test. The aim of this study was to determine whether the nadir SpO(2) differs from the end-6MWT SpO(2) in patients with chronic respiratory disease. A total of 86 subjects underwent the 6MWT according to a standardized protocol with continuous monitoring of SpO(2) by pulse oximeter. Comparison of nadir SpO(2) and end SpO(2) was made and the proportion of subjects with important desaturation according to each measure was determined. The effect of resting during the 6MWT on the likelihood of a significant difference between nadir and end SpO(2) was evaluated. A total of 29 subjects with chronic obstructive pulmonary disease (COPD; mean [SD] forced expiratory volume in 1 second [FEV(1)] 51[21] % predicted) and 57 with interstitial lung disease (ILD; TLCO 49[18] % predicted) were studied. Nadir SpO(2) was slightly lower than end-test SpO(2) (median 87% vs. 88%, p < 0.001) with differences ranging from 1% to 10%. Those who rested during the test (n = 14) were more likely to have a significant difference between nadir SpO(2) and end SpO(2) (p = 0.04). End SpO(2) did not accurately identify desaturation in 21% of subjects. No differences between COPD and ILD were observed. For most patients with chronic respiratory disease, the end SpO(2) and the nadir SpO( 2) are similar during the 6MWT. However, the end SpO(2) does not give an accurate estimate of nadir SpO(2) in patients who rest. Consideration should be given to the constant monitoring of SpO(2) during the 6MWT.     

Risk factors for syngeneic graft-versus-host disease after adult hematopoietic cell transplantation

Syngeneic graft-versus-host disease (sGVHD) has been described after hematopoietic cell transplantation (HCT) but remains poorly defined. We retrospectively reviewed adult syngeneic HCTs at our center (1980-2002) for sGVHD to investigate incidence, morbidity, and risk factors with a primary focus on parity. Among 119 transplantations, there were 21 cases of biopsy-proven sGVHD. The cumulative incidence was 18%, with multiorgan involvement in 6 cases and 1 death. sGVHD was more frequent when the donor was parous (32%) than nulliparous (9%) or male (13%; P = .03) and when the recipient was parous (31%) than nulliparous (7%) or male (13%; P = .02). Other univariable risk factors included older age (P < .01), busulfan/melphalan/thiotepa conditioning (P < .01), interleukin-2 (P = .02), HLA-A26 (P = .03), and more recent transplantation year (P < .01). Overall, risk factors were similar to those described in GVHD. Although an independent effect of parity could not be completely separated from other factors, donor and recipient pregnancy history merits further investigation.      

Distinct MHC class I and II alleles are associated with hepatitis C viral clearance, originating from a single source

The role of cytotoxic T lymphocyte responses, restricted by human leukocyte antigen (HLA) class I alleles, is recognized as highly significant in the successful clearance of hepatitis C virus (HCV). The frequency of class I alleles in females inoculated with HCV genotype 1b from a single source was examined for an association with outcome. Class I typing was performed using polymerase chain reaction sequence-specific primers in 227 female subjects: 141 had chronic infection and 86 had viral clearance. Statistical analysis included chi(2) testing and multiple logistic regression analysis. A*03, B*27, and Cw*01 occurred more frequently in those with viral clearance (39.5%, 14%, and 9.3%, respectively) compared with those with chronic infection (19.1%, 2.1%, and 1.4%, respectively; P < or = .005). B*08 occurred more often in those with chronic infection compared with viral clearance (39.7% vs. 19.8%; P =.002). In combination with previously reported class II allele associations, over 75% that successfully eliminate HCV carry either A*03, DRB1*0101, or *0401, compared with only 37% of those with chronic infection (P <.0001). The haplotypes A*03-B*07-DRB1*15-DQB1*0602 and A*02-B*27-Cw*01-DRB1*0101-DQB1*0501 are associated with viral clearance (P =.004 and.01, respectively). By multiple logistic regression analysis, the alleles A*03, B*27, DRB1*0101, *0401, and *15 are associated with viral clearance, and B*27 has the strongest association (odds ratio [OR] 7.99). The haplotype A*01-B*08-Cw*07-DRB1*03011-DQB1*0201 is associated with chronic infection (P =.002), being independent for DQB1*0201 (OR 0.27). In conclusion, certain class I alleles are associated with outcome in this homogeneous cohort. More significantly, either HLA-A*03, -DRB1*0101, or -*0401 are carried by an overwhelming majority of those subjects who successfully clear HCV.     

Factors influencing the development of Barrett's epithelium in the esophageal remnant postesophagectomy

BACKGROUND: Barrett's esophagus results from chronic reflux of both acid and bile. Reflux of gastric and duodenal contents is facilitated through the denervated stomach following esophagectomy, but the development of Barrett's changes in this model and the relationship to gastric and esophageal physiology is poorly understood. AIMS: To document the development of new Barrett's changes, i.e., columnar metaplasia or specialized intestinal metaplasia (SIM) above the anastomosis, and relate this to the recovery of gastric acid production, acid and bile reflux, manometry, and symptoms. PATIENTS AND METHODS: Forty-eight patients at a median follow-up of 26 months (range = 12-67) postesophagectomy underwent endoscopy with biopsies taken 1-2 cm above the anastomosis. The indication for esophagectomy had been adenocarcinoma (n = 27), high-grade dysplasia (n = 2), and squamous cell cancer (n = 19). Physiology studies were performed in 27 patients and included manometry (n = 25), intraluminal gastric pH (n = 24), as well as simultaneous 24-hour esophageal pH (n = 27) and bile monitoring (n = 20). RESULTS: Duodenogastric reflux increased over time, with differences between patients greater than and less than 3 years postesophagectomy for acid (p = 0.04) and bile (p = 0.02). Twenty-four patients (50%) developed columnar metaplasia and of these 13 had SIM. The prevalence of columnar metaplasia did not relate to the magnitude of acid or bile reflux, to preoperative neoadjuvant therapies, or to the original tumor histology. The duration of reflux was most significant, with increasing prevalence over time, with SIM in 13 patients at a median of 61 months postesophagectomy compared with 20 months in the 35 patients who were SIM-negative (p < 0.006). Supine reflux correlated with symptoms. CONCLUSIONS: The development of Barrett's epithelium is frequent after esophagectomy, is time-related, reflecting chronic acid and bile exposure, and is not specific for adenocarcinoma or the presence of previous Barrett's epithelium. This model may represent a useful in vivo model of the pathogenesis of Barrett's metaplasia and tumorigenesis.     

Chronic granulocytic leukaemia with Ph 1 negative cells in bone marrow and a ten year remission after busulphan hypoplasia

Summary. Following busulphan-induced bone marrow insufficiency a patient with chronic granulocytic leukaemia has had a remission lasting 10 yr. During this time repeated chromosome studies on bone marrow have shown the persistence of a majority of Ph¹ negative cells. The relationship of this finding to the unusually long remission is discussed.     

The effect of root canal preparation on microleakage within endodontically treated teeth: an in vitro study

AIM: The purpose of this study was to evaluate the effects of smear layer and canal instrumentation on leakage in root-filled teeth. METHODOLOGY: Six groups (n = 12) of freshly extracted human canines and premolars with closed apices and single roots were used. Groups A, B, C, and D were instrumented with engine-driven rotary nickel-titanium MCXIM files and Groups E and F were instrumented with conventional stainless steel hand files. Groups A, C, and E were flushed with 3.0 mL of 17.0% REDTA to remove the smear layer prior to obturation. All teeth were flushed with 5.25% NaOCl, then obturated with AH-26 sealer and either the lateral condensation (Groups C-E) or thermomechanical compaction technique (Groups A and B). Copper wire was placed coronally in contact with the gutta-percha in each tooth and, after immersion in 0.9% NaCl solution, a 10 volt dc voltage was connected between each tooth and a stainless steel electrode. The current flow in the circuit was observed for 45 days. One way ANOVA and Duncan's Multiple Range Test were used to compare Groups A-F at time intervals of 10, 20, 30 and 45 days and identify statistically significant differences. RESULTS: Significantly less microleakage occurred when the smear layer was removed and when the canals were obturated with thermoplasticized gutta-percha. Canals instrumented with engine-driven NiTi files exhibited less leakage than hand-instrumented canals irrespective of obturation method. CONCLUSIONS: Smear layer removal is beneficial to root canal sealing. Obturation with thermoplasticized gutta-percha provides a superior seal whilst canal instrumentation with engine-driven NiTi files reduces the extent of microleakage in root canals.     

Pall eBDS: an enhanced bacterial detection system for screening platelet concentrates

summary .   Bacterial contamination of blood components remains a significant problem in transfusion medicine. The Pall enhanced bacterial detection system (Pall eBDS) detects the presence of bacteria in leucodepleted platelet concentrates by measuring the reduction of oxygen in the sample, due to aerobic bacterial growth. Pooled platelet concentrates were spiked at 10 cfu mL⁻¹ with 10 organisms (one species per bag). Pall eBDS pouches were inoculated with the spiked platelet concentrates. After 24 and 30 h of incubation, the oxygen level was measured. A further set of pouches were taken from the inoculated platelet concentrates at 24 h. Incubation and reading intervals were as for the initial set of pouches. A sensitivity study was also performed comparing the Pall eBDS with the BacT/ALERT system. Spiking at 10 cfu mL⁻¹ and immediately sampling into Pall eBDS pouches resulted in 97·6 and 100% detection after an incubation period of 24 and 30 h, respectively. After 24 h of incubation of the spiked platelet concentrates and then sampling into Pall eBDS pouches, 99·1% detection was obtained after incubation for both 24 and 30 h. The sensitivity of the Pall eBDS and BacT/ALERT is similar and in the order of 1 cfu mL⁻¹. Implementation of either BacT/ALERT or Pall eBDS for routine screening of platelet concentrates has the potential to further increase the safety of the blood supply.